crypto/openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.436 2016/02/15 09:47:49 dtucker 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 "version.h"
 110 #include "ssherr.h"
 111 #include "myproposal.h"
 112
 113 #ifdef ENABLE_PKCS11
 114 #include "ssh-pkcs11.h"
 115 #endif
 116
 117 extern char *__progname;
 118
 119 /* Saves a copy of argv for setproctitle emulation */
 120 #ifndef HAVE_SETPROCTITLE
 121 static char **saved_av;
 122 #endif
 123
 124 /* Flag indicating whether debug mode is on.  May be set on the command line. */
 125 int debug_flag = 0;
 126
 127 /* Flag indicating whether a tty should be requested */
 128 int tty_flag = 0;
 129
 130 /* don't exec a shell */
 131 int no_shell_flag = 0;
 132
 133 /*
 134  * Flag indicating that nothing should be read from stdin.  This can be set
 135  * on the command line.
 136  */
 137 int stdin_null_flag = 0;
 138
 139 /*
 140  * Flag indicating that the current process should be backgrounded and
 141  * a new slave launched in the foreground for ControlPersist.
 142  */
 143 int need_controlpersist_detach = 0;
 144
 145 /* Copies of flags for ControlPersist foreground slave */
 146 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty;
 147
 148 /*
 149  * Flag indicating that ssh should fork after authentication.  This is useful
 150  * so that the passphrase can be entered manually, and then ssh goes to the
 151  * background.
 152  */
 153 int fork_after_authentication_flag = 0;
 154
 155 /* forward stdio to remote host and port */
 156 char *stdio_forward_host = NULL;
 157 int stdio_forward_port = 0;
 158
 159 /*
 160  * General data structure for command line options and options configurable
 161  * in configuration files.  See readconf.h.
 162  */
 163 Options options;
 164
 165 /* optional user configfile */
 166 char *config = NULL;
 167
 168 /*
 169  * Name of the host we are connecting to.  This is the name given on the
 170  * command line, or the HostName specified for the user-supplied name in a
 171  * configuration file.
 172  */
 173 char *host;
 174
 175 /* socket address the host resolves to */
 176 struct sockaddr_storage hostaddr;
 177
 178 /* Private host keys. */
 179 Sensitive sensitive_data;
 180
 181 /* Original real UID. */
 182 uid_t original_real_uid;
 183 uid_t original_effective_uid;
 184
 185 /* command to be executed */
 186 Buffer command;
 187
 188 /* Should we execute a command or invoke a subsystem? */
 189 int subsystem_flag = 0;
 190
 191 /* # of replies received for global requests */
 192 static int remote_forward_confirms_received = 0;
 193
 194 /* mux.c */
 195 extern int muxserver_sock;
 196 extern u_int muxclient_command;
 197
 198 /* Prints a help message to the user.  This function never returns. */
 199
 200 static void
 201 usage(void)
 202 {
 203         fprintf(stderr,
 204 "usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n"
 205 "           [-D [bind_address:]port] [-E log_file] [-e escape_char]\n"
 206 "           [-F configfile] [-I pkcs11] [-i identity_file] [-L address]\n"
 207 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 208 "           [-Q query_option] [-R address] [-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, "%d", 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  * Attempt to resolve a numeric host address / port to a single address.
 280  * Returns a canonical address string.
 281  * Returns NULL on failure.
 282  * NB. this function must operate with a options having undefined members.
 283  */
 284 static struct addrinfo *
 285 resolve_addr(const char *name, int port, char *caddr, size_t clen)
 286 {
 287         char addr[NI_MAXHOST], strport[NI_MAXSERV];
 288         struct addrinfo hints, *res;
 289         int gaierr;
 290
 291         if (port <= 0)
 292                 port = default_ssh_port();
 293         snprintf(strport, sizeof strport, "%u", port);
 294         memset(&hints, 0, sizeof(hints));
 295         hints.ai_family = options.address_family == -1 ?
 296             AF_UNSPEC : options.address_family;
 297         hints.ai_socktype = SOCK_STREAM;
 298         hints.ai_flags = AI_NUMERICHOST|AI_NUMERICSERV;
 299         if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) {
 300                 debug2("%s: could not resolve name %.100s as address: %s",
 301                     __func__, name, ssh_gai_strerror(gaierr));
 302                 return NULL;
 303         }
 304         if (res == NULL) {
 305                 debug("%s: getaddrinfo %.100s returned no addresses",
 306                  __func__, name);
 307                 return NULL;
 308         }
 309         if (res->ai_next != NULL) {
 310                 debug("%s: getaddrinfo %.100s returned multiple addresses",
 311                     __func__, name);
 312                 goto fail;
 313         }
 314         if ((gaierr = getnameinfo(res->ai_addr, res->ai_addrlen,
 315             addr, sizeof(addr), NULL, 0, NI_NUMERICHOST)) != 0) {
 316                 debug("%s: Could not format address for name %.100s: %s",
 317                     __func__, name, ssh_gai_strerror(gaierr));
 318                 goto fail;
 319         }
 320         if (strlcpy(caddr, addr, clen) >= clen) {
 321                 error("%s: host \"%s\" addr \"%s\" too long (max %lu)",
 322                     __func__, name,  addr, (u_long)clen);
 323                 if (clen > 0)
 324                         *caddr = '\0';
 325  fail:
 326                 freeaddrinfo(res);
 327                 return NULL;
 328         }
 329         return res;
 330 }
 331
 332 /*
 333  * Check whether the cname is a permitted replacement for the hostname
 334  * and perform the replacement if it is.
 335  * NB. this function must operate with a options having undefined members.
 336  */
 337 static int
 338 check_follow_cname(char **namep, const char *cname)
 339 {
 340         int i;
 341         struct allowed_cname *rule;
 342
 343         if (*cname == '\0' || options.num_permitted_cnames == 0 ||
 344             strcmp(*namep, cname) == 0)
 345                 return 0;
 346         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 347                 return 0;
 348         /*
 349          * Don't attempt to canonicalize names that will be interpreted by
 350          * a proxy unless the user specifically requests so.
 351          */
 352         if (!option_clear_or_none(options.proxy_command) &&
 353             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 354                 return 0;
 355         debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname);
 356         for (i = 0; i < options.num_permitted_cnames; i++) {
 357                 rule = options.permitted_cnames + i;
 358                 if (match_pattern_list(*namep, rule->source_list, 1) != 1 ||
 359                     match_pattern_list(cname, rule->target_list, 1) != 1)
 360                         continue;
 361                 verbose("Canonicalized DNS aliased hostname "
 362                     "\"%s\" => \"%s\"", *namep, cname);
 363                 free(*namep);
 364                 *namep = xstrdup(cname);
 365                 return 1;
 366         }
 367         return 0;
 368 }
 369
 370 /*
 371  * Attempt to resolve the supplied hostname after applying the user's
 372  * canonicalization rules. Returns the address list for the host or NULL
 373  * if no name was found after canonicalization.
 374  * NB. this function must operate with a options having undefined members.
 375  */
 376 static struct addrinfo *
 377 resolve_canonicalize(char **hostp, int port)
 378 {
 379         int i, ndots;
 380         char *cp, *fullhost, newname[NI_MAXHOST];
 381         struct addrinfo *addrs;
 382
 383         if (options.canonicalize_hostname == SSH_CANONICALISE_NO)
 384                 return NULL;
 385
 386         /*
 387          * Don't attempt to canonicalize names that will be interpreted by
 388          * a proxy unless the user specifically requests so.
 389          */
 390         if (!option_clear_or_none(options.proxy_command) &&
 391             options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS)
 392                 return NULL;
 393
 394         /* Try numeric hostnames first */
 395         if ((addrs = resolve_addr(*hostp, port,
 396             newname, sizeof(newname))) != NULL) {
 397                 debug2("%s: hostname %.100s is address", __func__, *hostp);
 398                 if (strcasecmp(*hostp, newname) != 0) {
 399                         debug2("%s: canonicalised address \"%s\" => \"%s\"",
 400                             __func__, *hostp, newname);
 401                         free(*hostp);
 402                         *hostp = xstrdup(newname);
 403                 }
 404                 return addrs;
 405         }
 406
 407         /* If domain name is anchored, then resolve it now */
 408         if ((*hostp)[strlen(*hostp) - 1] == '.') {
 409                 debug3("%s: name is fully qualified", __func__);
 410                 fullhost = xstrdup(*hostp);
 411                 if ((addrs = resolve_host(fullhost, port, 0,
 412                     newname, sizeof(newname))) != NULL)
 413                         goto found;
 414                 free(fullhost);
 415                 goto notfound;
 416         }
 417
 418         /* Don't apply canonicalization to sufficiently-qualified hostnames */
 419         ndots = 0;
 420         for (cp = *hostp; *cp != '\0'; cp++) {
 421                 if (*cp == '.')
 422                         ndots++;
 423         }
 424         if (ndots > options.canonicalize_max_dots) {
 425                 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)",
 426                     __func__, *hostp, options.canonicalize_max_dots);
 427                 return NULL;
 428         }
 429         /* Attempt each supplied suffix */
 430         for (i = 0; i < options.num_canonical_domains; i++) {
 431                 *newname = '\0';
 432                 xasprintf(&fullhost, "%s.%s.", *hostp,
 433                     options.canonical_domains[i]);
 434                 debug3("%s: attempting \"%s\" => \"%s\"", __func__,
 435                     *hostp, fullhost);
 436                 if ((addrs = resolve_host(fullhost, port, 0,
 437                     newname, sizeof(newname))) == NULL) {
 438                         free(fullhost);
 439                         continue;
 440                 }
 441  found:
 442                 /* Remove trailing '.' */
 443                 fullhost[strlen(fullhost) - 1] = '\0';
 444                 /* Follow CNAME if requested */
 445                 if (!check_follow_cname(&fullhost, newname)) {
 446                         debug("Canonicalized hostname \"%s\" => \"%s\"",
 447                             *hostp, fullhost);
 448                 }
 449                 free(*hostp);
 450                 *hostp = fullhost;
 451                 return addrs;
 452         }
 453  notfound:
 454         if (!options.canonicalize_fallback_local)
 455                 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp);
 456         debug2("%s: host %s not found in any suffix", __func__, *hostp);
 457         return NULL;
 458 }
 459
 460 /*
 461  * Read per-user configuration file.  Ignore the system wide config
 462  * file if the user specifies a config file on the command line.
 463  */
 464 static void
 465 process_config_files(const char *host_arg, struct passwd *pw, int post_canon)
 466 {
 467         char buf[PATH_MAX];
 468         int r;
 469
 470         if (config != NULL) {
 471                 if (strcasecmp(config, "none") != 0 &&
 472                     !read_config_file(config, pw, host, host_arg, &options,
 473                     SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 0)))
 474                         fatal("Can't open user config file %.100s: "
 475                             "%.100s", config, strerror(errno));
 476         } else {
 477                 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir,
 478                     _PATH_SSH_USER_CONFFILE);
 479                 if (r > 0 && (size_t)r < sizeof(buf))
 480                         (void)read_config_file(buf, pw, host, host_arg,
 481                             &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF |
 482                             (post_canon ? SSHCONF_POSTCANON : 0));
 483
 484                 /* Read systemwide configuration file after user config. */
 485                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw,
 486                     host, host_arg, &options,
 487                     post_canon ? SSHCONF_POSTCANON : 0);
 488         }
 489 }
 490
 491 /* Rewrite the port number in an addrinfo list of addresses */
 492 static void
 493 set_addrinfo_port(struct addrinfo *addrs, int port)
 494 {
 495         struct addrinfo *addr;
 496
 497         for (addr = addrs; addr != NULL; addr = addr->ai_next) {
 498                 switch (addr->ai_family) {
 499                 case AF_INET:
 500                         ((struct sockaddr_in *)addr->ai_addr)->
 501                             sin_port = htons(port);
 502                         break;
 503                 case AF_INET6:
 504                         ((struct sockaddr_in6 *)addr->ai_addr)->
 505                             sin6_port = htons(port);
 506                         break;
 507                 }
 508         }
 509 }
 510
 511 /*
 512  * Main program for the ssh client.
 513  */
 514 int
 515 main(int ac, char **av)
 516 {
 517         int i, r, opt, exit_status, use_syslog, config_test = 0;
 518         char *p, *cp, *line, *argv0, buf[PATH_MAX], *host_arg, *logfile;
 519         char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV];
 520         char cname[NI_MAXHOST], uidstr[32], *conn_hash_hex;
 521         struct stat st;
 522         struct passwd *pw;
 523         int timeout_ms;
 524         extern int optind, optreset;
 525         extern char *optarg;
 526         struct Forward fwd;
 527         struct addrinfo *addrs = NULL;
 528         struct ssh_digest_ctx *md;
 529         u_char conn_hash[SSH_DIGEST_MAX_LENGTH];
 530
 531         ssh_malloc_init();      /* must be called before any mallocs */
 532         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 533         sanitise_stdfd();
 534
 535         __progname = ssh_get_progname(av[0]);
 536
 537 #ifndef HAVE_SETPROCTITLE
 538         /* Prepare for later setproctitle emulation */
 539         /* Save argv so it isn't clobbered by setproctitle() emulation */
 540         saved_av = xcalloc(ac + 1, sizeof(*saved_av));
 541         for (i = 0; i < ac; i++)
 542                 saved_av[i] = xstrdup(av[i]);
 543         saved_av[i] = NULL;
 544         compat_init_setproctitle(ac, av);
 545         av = saved_av;
 546 #endif
 547
 548         /*
 549          * Discard other fds that are hanging around. These can cause problem
 550          * with backgrounded ssh processes started by ControlPersist.
 551          */
 552         closefrom(STDERR_FILENO + 1);
 553
 554         /*
 555          * Save the original real uid.  It will be needed later (uid-swapping
 556          * may clobber the real uid).
 557          */
 558         original_real_uid = getuid();
 559         original_effective_uid = geteuid();
 560
 561         /*
 562          * Use uid-swapping to give up root privileges for the duration of
 563          * option processing.  We will re-instantiate the rights when we are
 564          * ready to create the privileged port, and will permanently drop
 565          * them when the port has been created (actually, when the connection
 566          * has been made, as we may need to create the port several times).
 567          */
 568         PRIV_END;
 569
 570 #ifdef HAVE_SETRLIMIT
 571         /* If we are installed setuid root be careful to not drop core. */
 572         if (original_real_uid != original_effective_uid) {
 573                 struct rlimit rlim;
 574                 rlim.rlim_cur = rlim.rlim_max = 0;
 575                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 576                         fatal("setrlimit failed: %.100s", strerror(errno));
 577         }
 578 #endif
 579         /* Get user data. */
 580         pw = getpwuid(original_real_uid);
 581         if (!pw) {
 582                 logit("No user exists for uid %lu", (u_long)original_real_uid);
 583                 exit(255);
 584         }
 585         /* Take a copy of the returned structure. */
 586         pw = pwcopy(pw);
 587
 588         /*
 589          * Set our umask to something reasonable, as some files are created
 590          * with the default umask.  This will make them world-readable but
 591          * writable only by the owner, which is ok for all files for which we
 592          * don't set the modes explicitly.
 593          */
 594         umask(022);
 595
 596         /*
 597          * Initialize option structure to indicate that no values have been
 598          * set.
 599          */
 600         initialize_options(&options);
 601
 602         /* Parse command-line arguments. */
 603         host = NULL;
 604         use_syslog = 0;
 605         logfile = NULL;
 606         argv0 = av[0];
 607
 608  again:
 609         while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx"
 610             "ACD:E:F:GI:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) {
 611                 switch (opt) {
 612                 case '1':
 613                         options.protocol = SSH_PROTO_1;
 614                         break;
 615                 case '2':
 616                         options.protocol = SSH_PROTO_2;
 617                         break;
 618                 case '4':
 619                         options.address_family = AF_INET;
 620                         break;
 621                 case '6':
 622                         options.address_family = AF_INET6;
 623                         break;
 624                 case 'n':
 625                         stdin_null_flag = 1;
 626                         break;
 627                 case 'f':
 628                         fork_after_authentication_flag = 1;
 629                         stdin_null_flag = 1;
 630                         break;
 631                 case 'x':
 632                         options.forward_x11 = 0;
 633                         break;
 634                 case 'X':
 635                         options.forward_x11 = 1;
 636                         break;
 637                 case 'y':
 638                         use_syslog = 1;
 639                         break;
 640                 case 'E':
 641                         logfile = optarg;
 642                         break;
 643                 case 'G':
 644                         config_test = 1;
 645                         break;
 646                 case 'Y':
 647                         options.forward_x11 = 1;
 648                         options.forward_x11_trusted = 1;
 649                         break;
 650                 case 'g':
 651                         options.fwd_opts.gateway_ports = 1;
 652                         break;
 653                 case 'O':
 654                         if (stdio_forward_host != NULL)
 655                                 fatal("Cannot specify multiplexing "
 656                                     "command with -W");
 657                         else if (muxclient_command != 0)
 658                                 fatal("Multiplexing command already specified");
 659                         if (strcmp(optarg, "check") == 0)
 660                                 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK;
 661                         else if (strcmp(optarg, "forward") == 0)
 662                                 muxclient_command = SSHMUX_COMMAND_FORWARD;
 663                         else if (strcmp(optarg, "exit") == 0)
 664                                 muxclient_command = SSHMUX_COMMAND_TERMINATE;
 665                         else if (strcmp(optarg, "stop") == 0)
 666                                 muxclient_command = SSHMUX_COMMAND_STOP;
 667                         else if (strcmp(optarg, "cancel") == 0)
 668                                 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD;
 669                         else
 670                                 fatal("Invalid multiplex command.");
 671                         break;
 672                 case 'P':       /* deprecated */
 673                         options.use_privileged_port = 0;
 674                         break;
 675                 case 'Q':
 676                         cp = NULL;
 677                         if (strcmp(optarg, "cipher") == 0)
 678                                 cp = cipher_alg_list('\n', 0);
 679                         else if (strcmp(optarg, "cipher-auth") == 0)
 680                                 cp = cipher_alg_list('\n', 1);
 681                         else if (strcmp(optarg, "mac") == 0)
 682                                 cp = mac_alg_list('\n');
 683                         else if (strcmp(optarg, "kex") == 0)
 684                                 cp = kex_alg_list('\n');
 685                         else if (strcmp(optarg, "key") == 0)
 686                                 cp = key_alg_list(0, 0);
 687                         else if (strcmp(optarg, "key-cert") == 0)
 688                                 cp = key_alg_list(1, 0);
 689                         else if (strcmp(optarg, "key-plain") == 0)
 690                                 cp = key_alg_list(0, 1);
 691                         else if (strcmp(optarg, "protocol-version") == 0) {
 692 #ifdef WITH_SSH1
 693                                 cp = xstrdup("1\n2");
 694 #else
 695                                 cp = xstrdup("2");
 696 #endif
 697                         }
 698                         if (cp == NULL)
 699                                 fatal("Unsupported query \"%s\"", optarg);
 700                         printf("%s\n", cp);
 701                         free(cp);
 702                         exit(0);
 703                         break;
 704                 case 'a':
 705                         options.forward_agent = 0;
 706                         break;
 707                 case 'A':
 708                         options.forward_agent = 1;
 709                         break;
 710                 case 'k':
 711                         options.gss_deleg_creds = 0;
 712                         break;
 713                 case 'K':
 714                         options.gss_authentication = 1;
 715                         options.gss_deleg_creds = 1;
 716                         break;
 717                 case 'i':
 718                         p = tilde_expand_filename(optarg, original_real_uid);
 719                         if (stat(p, &st) < 0)
 720                                 fprintf(stderr, "Warning: Identity file %s "
 721                                     "not accessible: %s.\n", p,
 722                                     strerror(errno));
 723                         else
 724                                 add_identity_file(&options, NULL, p, 1);
 725                         free(p);
 726                         break;
 727                 case 'I':
 728 #ifdef ENABLE_PKCS11
 729                         free(options.pkcs11_provider);
 730                         options.pkcs11_provider = xstrdup(optarg);
 731 #else
 732                         fprintf(stderr, "no support for PKCS#11.\n");
 733 #endif
 734                         break;
 735                 case 't':
 736                         if (options.request_tty == REQUEST_TTY_YES)
 737                                 options.request_tty = REQUEST_TTY_FORCE;
 738                         else
 739                                 options.request_tty = REQUEST_TTY_YES;
 740                         break;
 741                 case 'v':
 742                         if (debug_flag == 0) {
 743                                 debug_flag = 1;
 744                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 745                         } else {
 746                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 747                                         options.log_level++;
 748                         }
 749                         break;
 750                 case 'V':
 751                         if (options.version_addendum &&
 752                             *options.version_addendum != '\0')
 753                                 fprintf(stderr, "%s %s, %s\n", SSH_RELEASE,
 754                                     options.version_addendum,
 755                                     OPENSSL_VERSION);
 756                         else
 757                                 fprintf(stderr, "%s, %s\n", SSH_RELEASE,
 758                                     OPENSSL_VERSION);
 759                         if (opt == 'V')
 760                                 exit(0);
 761                         break;
 762                 case 'w':
 763                         if (options.tun_open == -1)
 764                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 765                         options.tun_local = a2tun(optarg, &options.tun_remote);
 766                         if (options.tun_local == SSH_TUNID_ERR) {
 767                                 fprintf(stderr,
 768                                     "Bad tun device '%s'\n", optarg);
 769                                 exit(255);
 770                         }
 771                         break;
 772                 case 'W':
 773                         if (stdio_forward_host != NULL)
 774                                 fatal("stdio forward already specified");
 775                         if (muxclient_command != 0)
 776                                 fatal("Cannot specify stdio forward with -O");
 777                         if (parse_forward(&fwd, optarg, 1, 0)) {
 778                                 stdio_forward_host = fwd.listen_host;
 779                                 stdio_forward_port = fwd.listen_port;
 780                                 free(fwd.connect_host);
 781                         } else {
 782                                 fprintf(stderr,
 783                                     "Bad stdio forwarding specification '%s'\n",
 784                                     optarg);
 785                                 exit(255);
 786                         }
 787                         options.request_tty = REQUEST_TTY_NO;
 788                         no_shell_flag = 1;
 789                         options.clear_forwardings = 1;
 790                         options.exit_on_forward_failure = 1;
 791                         break;
 792                 case 'q':
 793                         options.log_level = SYSLOG_LEVEL_QUIET;
 794                         break;
 795                 case 'e':
 796                         if (optarg[0] == '^' && optarg[2] == 0 &&
 797                             (u_char) optarg[1] >= 64 &&
 798                             (u_char) optarg[1] < 128)
 799                                 options.escape_char = (u_char) optarg[1] & 31;
 800                         else if (strlen(optarg) == 1)
 801                                 options.escape_char = (u_char) optarg[0];
 802                         else if (strcmp(optarg, "none") == 0)
 803                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 804                         else {
 805                                 fprintf(stderr, "Bad escape character '%s'.\n",
 806                                     optarg);
 807                                 exit(255);
 808                         }
 809                         break;
 810                 case 'c':
 811                         if (ciphers_valid(*optarg == '+' ?
 812                             optarg + 1 : optarg)) {
 813                                 /* SSH2 only */
 814                                 free(options.ciphers);
 815                                 options.ciphers = xstrdup(optarg);
 816                                 options.cipher = SSH_CIPHER_INVALID;
 817                                 break;
 818                         }
 819                         /* SSH1 only */
 820                         options.cipher = cipher_number(optarg);
 821                         if (options.cipher == -1) {
 822                                 fprintf(stderr, "Unknown cipher type '%s'\n",
 823                                     optarg);
 824                                 exit(255);
 825                         }
 826                         if (options.cipher == SSH_CIPHER_3DES)
 827                                 options.ciphers = xstrdup("3des-cbc");
 828                         else if (options.cipher == SSH_CIPHER_BLOWFISH)
 829                                 options.ciphers = xstrdup("blowfish-cbc");
 830                         else
 831                                 options.ciphers = xstrdup(KEX_CLIENT_ENCRYPT);
 832                         break;
 833                 case 'm':
 834                         if (mac_valid(optarg)) {
 835                                 free(options.macs);
 836                                 options.macs = xstrdup(optarg);
 837                         } else {
 838                                 fprintf(stderr, "Unknown mac type '%s'\n",
 839                                     optarg);
 840                                 exit(255);
 841                         }
 842                         break;
 843                 case 'M':
 844                         if (options.control_master == SSHCTL_MASTER_YES)
 845                                 options.control_master = SSHCTL_MASTER_ASK;
 846                         else
 847                                 options.control_master = SSHCTL_MASTER_YES;
 848                         break;
 849                 case 'p':
 850                         options.port = a2port(optarg);
 851                         if (options.port <= 0) {
 852                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 853                                 exit(255);
 854                         }
 855                         break;
 856                 case 'l':
 857                         options.user = optarg;
 858                         break;
 859
 860                 case 'L':
 861                         if (parse_forward(&fwd, optarg, 0, 0))
 862                                 add_local_forward(&options, &fwd);
 863                         else {
 864                                 fprintf(stderr,
 865                                     "Bad local forwarding specification '%s'\n",
 866                                     optarg);
 867                                 exit(255);
 868                         }
 869                         break;
 870
 871                 case 'R':
 872                         if (parse_forward(&fwd, optarg, 0, 1)) {
 873                                 add_remote_forward(&options, &fwd);
 874                         } else {
 875                                 fprintf(stderr,
 876                                     "Bad remote forwarding specification "
 877                                     "'%s'\n", optarg);
 878                                 exit(255);
 879                         }
 880                         break;
 881
 882                 case 'D':
 883                         if (parse_forward(&fwd, optarg, 1, 0)) {
 884                                 add_local_forward(&options, &fwd);
 885                         } else {
 886                                 fprintf(stderr,
 887                                     "Bad dynamic forwarding specification "
 888                                     "'%s'\n", optarg);
 889                                 exit(255);
 890                         }
 891                         break;
 892
 893                 case 'C':
 894                         options.compression = 1;
 895                         break;
 896                 case 'N':
 897                         no_shell_flag = 1;
 898                         options.request_tty = REQUEST_TTY_NO;
 899                         break;
 900                 case 'T':
 901                         options.request_tty = REQUEST_TTY_NO;
 902                         break;
 903                 case 'o':
 904                         line = xstrdup(optarg);
 905                         if (process_config_line(&options, pw,
 906                             host ? host : "", host ? host : "", line,
 907                             "command-line", 0, NULL, SSHCONF_USERCONF) != 0)
 908                                 exit(255);
 909                         free(line);
 910                         break;
 911                 case 's':
 912                         subsystem_flag = 1;
 913                         break;
 914                 case 'S':
 915                         free(options.control_path);
 916                         options.control_path = xstrdup(optarg);
 917                         break;
 918                 case 'b':
 919                         options.bind_address = optarg;
 920                         break;
 921                 case 'F':
 922                         config = optarg;
 923                         break;
 924                 default:
 925                         usage();
 926                 }
 927         }
 928
 929         ac -= optind;
 930         av += optind;
 931
 932         if (ac > 0 && !host) {
 933                 if (strrchr(*av, '@')) {
 934                         p = xstrdup(*av);
 935                         cp = strrchr(p, '@');
 936                         if (cp == NULL || cp == p)
 937                                 usage();
 938                         options.user = p;
 939                         *cp = '\0';
 940                         host = xstrdup(++cp);
 941                 } else
 942                         host = xstrdup(*av);
 943                 if (ac > 1) {
 944                         optind = optreset = 1;
 945                         goto again;
 946                 }
 947                 ac--, av++;
 948         }
 949
 950         /* Check that we got a host name. */
 951         if (!host)
 952                 usage();
 953
 954         host_arg = xstrdup(host);
 955
 956 #ifdef WITH_OPENSSL
 957         OpenSSL_add_all_algorithms();
 958         ERR_load_crypto_strings();
 959 #endif
 960
 961         /* Initialize the command to execute on remote host. */
 962         buffer_init(&command);
 963
 964         /*
 965          * Save the command to execute on the remote host in a buffer. There
 966          * is no limit on the length of the command, except by the maximum
 967          * packet size.  Also sets the tty flag if there is no command.
 968          */
 969         if (!ac) {
 970                 /* No command specified - execute shell on a tty. */
 971                 if (subsystem_flag) {
 972                         fprintf(stderr,
 973                             "You must specify a subsystem to invoke.\n");
 974                         usage();
 975                 }
 976         } else {
 977                 /* A command has been specified.  Store it into the buffer. */
 978                 for (i = 0; i < ac; i++) {
 979                         if (i)
 980                                 buffer_append(&command, " ", 1);
 981                         buffer_append(&command, av[i], strlen(av[i]));
 982                 }
 983         }
 984
 985         /* Cannot fork to background if no command. */
 986         if (fork_after_authentication_flag && buffer_len(&command) == 0 &&
 987             !no_shell_flag)
 988                 fatal("Cannot fork into background without a command "
 989                     "to execute.");
 990
 991         /*
 992          * Initialize "log" output.  Since we are the client all output
 993          * goes to stderr unless otherwise specified by -y or -E.
 994          */
 995         if (use_syslog && logfile != NULL)
 996                 fatal("Can't specify both -y and -E");
 997         if (logfile != NULL)
 998                 log_redirect_stderr_to(logfile);
 999         log_init(argv0,
1000             options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
1001             SYSLOG_FACILITY_USER, !use_syslog);
1002
1003         if (debug_flag)
1004                 /* version_addendum is always NULL at this point */
1005                 logit("%s, %s", SSH_RELEASE, OPENSSL_VERSION);
1006
1007         /* Parse the configuration files */
1008         process_config_files(host_arg, pw, 0);
1009
1010         /* Hostname canonicalisation needs a few options filled. */
1011         fill_default_options_for_canonicalization(&options);
1012
1013         /* If the user has replaced the hostname then take it into use now */
1014         if (options.hostname != NULL) {
1015                 /* NB. Please keep in sync with readconf.c:match_cfg_line() */
1016                 cp = percent_expand(options.hostname,
1017                     "h", host, (char *)NULL);
1018                 free(host);
1019                 host = cp;
1020                 free(options.hostname);
1021                 options.hostname = xstrdup(host);
1022         }
1023
1024         /* If canonicalization requested then try to apply it */
1025         lowercase(host);
1026         if (options.canonicalize_hostname != SSH_CANONICALISE_NO)
1027                 addrs = resolve_canonicalize(&host, options.port);
1028
1029         /*
1030          * If CanonicalizePermittedCNAMEs have been specified but
1031          * other canonicalization did not happen (by not being requested
1032          * or by failing with fallback) then the hostname may still be changed
1033          * as a result of CNAME following.
1034          *
1035          * Try to resolve the bare hostname name using the system resolver's
1036          * usual search rules and then apply the CNAME follow rules.
1037          *
1038          * Skip the lookup if a ProxyCommand is being used unless the user
1039          * has specifically requested canonicalisation for this case via
1040          * CanonicalizeHostname=always
1041          */
1042         if (addrs == NULL && options.num_permitted_cnames != 0 &&
1043             (option_clear_or_none(options.proxy_command) ||
1044             options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) {
1045                 if ((addrs = resolve_host(host, options.port,
1046                     option_clear_or_none(options.proxy_command),
1047                     cname, sizeof(cname))) == NULL) {
1048                         /* Don't fatal proxied host names not in the DNS */
1049                         if (option_clear_or_none(options.proxy_command))
1050                                 cleanup_exit(255); /* logged in resolve_host */
1051                 } else
1052                         check_follow_cname(&host, cname);
1053         }
1054
1055         /*
1056          * If canonicalisation is enabled then re-parse the configuration
1057          * files as new stanzas may match.
1058          */
1059         if (options.canonicalize_hostname != 0) {
1060                 debug("Re-reading configuration after hostname "
1061                     "canonicalisation");
1062                 free(options.hostname);
1063                 options.hostname = xstrdup(host);
1064                 process_config_files(host_arg, pw, 1);
1065                 /*
1066                  * Address resolution happens early with canonicalisation
1067                  * enabled and the port number may have changed since, so
1068                  * reset it in address list
1069                  */
1070                 if (addrs != NULL && options.port > 0)
1071                         set_addrinfo_port(addrs, options.port);
1072         }
1073
1074         /* Fill configuration defaults. */
1075         fill_default_options(&options);
1076
1077         if (options.port == 0)
1078                 options.port = default_ssh_port();
1079         channel_set_af(options.address_family);
1080
1081         /* Tidy and check options */
1082         if (options.host_key_alias != NULL)
1083                 lowercase(options.host_key_alias);
1084         if (options.proxy_command != NULL &&
1085             strcmp(options.proxy_command, "-") == 0 &&
1086             options.proxy_use_fdpass)
1087                 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible");
1088         if (options.control_persist &&
1089             options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
1090                 debug("UpdateHostKeys=ask is incompatible with ControlPersist; "
1091                     "disabling");
1092                 options.update_hostkeys = 0;
1093         }
1094         if (options.connection_attempts <= 0)
1095                 fatal("Invalid number of ConnectionAttempts");
1096 #ifndef HAVE_CYGWIN
1097         if (original_effective_uid != 0)
1098                 options.use_privileged_port = 0;
1099 #endif
1100
1101         /* reinit */
1102         log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog);
1103
1104         if (options.request_tty == REQUEST_TTY_YES ||
1105             options.request_tty == REQUEST_TTY_FORCE)
1106                 tty_flag = 1;
1107
1108         /* Allocate a tty by default if no command specified. */
1109         if (buffer_len(&command) == 0)
1110                 tty_flag = options.request_tty != REQUEST_TTY_NO;
1111
1112         /* Force no tty */
1113         if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0)
1114                 tty_flag = 0;
1115         /* Do not allocate a tty if stdin is not a tty. */
1116         if ((!isatty(fileno(stdin)) || stdin_null_flag) &&
1117             options.request_tty != REQUEST_TTY_FORCE) {
1118                 if (tty_flag)
1119                         logit("Pseudo-terminal will not be allocated because "
1120                             "stdin is not a terminal.");
1121                 tty_flag = 0;
1122         }
1123
1124         seed_rng();
1125
1126         if (options.user == NULL)
1127                 options.user = xstrdup(pw->pw_name);
1128
1129         if (gethostname(thishost, sizeof(thishost)) == -1)
1130                 fatal("gethostname: %s", strerror(errno));
1131         strlcpy(shorthost, thishost, sizeof(shorthost));
1132         shorthost[strcspn(thishost, ".")] = '\0';
1133         snprintf(portstr, sizeof(portstr), "%d", options.port);
1134         snprintf(uidstr, sizeof(uidstr), "%d", pw->pw_uid);
1135
1136         /* Find canonic host name. */
1137         if (strchr(host, '.') == 0) {
1138                 struct addrinfo hints;
1139                 struct addrinfo *ai = NULL;
1140                 int errgai;
1141                 memset(&hints, 0, sizeof(hints));
1142                 hints.ai_family = options.address_family;
1143                 hints.ai_flags = AI_CANONNAME;
1144                 hints.ai_socktype = SOCK_STREAM;
1145                 errgai = getaddrinfo(host, NULL, &hints, &ai);
1146                 if (errgai == 0) {
1147                         if (ai->ai_canonname != NULL)
1148                                 host = xstrdup(ai->ai_canonname);
1149                         freeaddrinfo(ai);
1150                 }
1151         }
1152
1153         if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL ||
1154             ssh_digest_update(md, thishost, strlen(thishost)) < 0 ||
1155             ssh_digest_update(md, host, strlen(host)) < 0 ||
1156             ssh_digest_update(md, portstr, strlen(portstr)) < 0 ||
1157             ssh_digest_update(md, options.user, strlen(options.user)) < 0 ||
1158             ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0)
1159                 fatal("%s: mux digest failed", __func__);
1160         ssh_digest_free(md);
1161         conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1));
1162
1163         if (options.local_command != NULL) {
1164                 debug3("expanding LocalCommand: %s", options.local_command);
1165                 cp = options.local_command;
1166                 options.local_command = percent_expand(cp,
1167                     "C", conn_hash_hex,
1168                     "L", shorthost,
1169                     "d", pw->pw_dir,
1170                     "h", host,
1171                     "l", thishost,
1172                     "n", host_arg,
1173                     "p", portstr,
1174                     "r", options.user,
1175                     "u", pw->pw_name,
1176                     (char *)NULL);
1177                 debug3("expanded LocalCommand: %s", options.local_command);
1178                 free(cp);
1179         }
1180
1181         if (options.control_path != NULL) {
1182                 cp = tilde_expand_filename(options.control_path,
1183                     original_real_uid);
1184                 free(options.control_path);
1185                 options.control_path = percent_expand(cp,
1186                     "C", conn_hash_hex,
1187                     "L", shorthost,
1188                     "h", host,
1189                     "l", thishost,
1190                     "n", host_arg,
1191                     "p", portstr,
1192                     "r", options.user,
1193                     "u", pw->pw_name,
1194                     "i", uidstr,
1195                     (char *)NULL);
1196                 free(cp);
1197         }
1198         free(conn_hash_hex);
1199
1200         if (config_test) {
1201                 dump_client_config(&options, host);
1202                 exit(0);
1203         }
1204
1205         if (muxclient_command != 0 && options.control_path == NULL)
1206                 fatal("No ControlPath specified for \"-O\" command");
1207         if (options.control_path != NULL)
1208                 muxclient(options.control_path);
1209
1210         /*
1211          * If hostname canonicalisation was not enabled, then we may not
1212          * have yet resolved the hostname. Do so now.
1213          */
1214         if (addrs == NULL && options.proxy_command == NULL) {
1215                 debug2("resolving \"%s\" port %d", host, options.port);
1216                 if ((addrs = resolve_host(host, options.port, 1,
1217                     cname, sizeof(cname))) == NULL)
1218                         cleanup_exit(255); /* resolve_host logs the error */
1219         }
1220
1221         timeout_ms = options.connection_timeout * 1000;
1222
1223         /* Open a connection to the remote host. */
1224         if (ssh_connect(host, addrs, &hostaddr, options.port,
1225             options.address_family, options.connection_attempts,
1226             &timeout_ms, options.tcp_keep_alive,
1227             options.use_privileged_port) != 0)
1228                 exit(255);
1229
1230         if (addrs != NULL)
1231                 freeaddrinfo(addrs);
1232
1233         packet_set_timeout(options.server_alive_interval,
1234             options.server_alive_count_max);
1235
1236         if (timeout_ms > 0)
1237                 debug3("timeout: %d ms remain after connect", timeout_ms);
1238
1239         /*
1240          * If we successfully made the connection, load the host private key
1241          * in case we will need it later for combined rsa-rhosts
1242          * authentication. This must be done before releasing extra
1243          * privileges, because the file is only readable by root.
1244          * If we cannot access the private keys, load the public keys
1245          * instead and try to execute the ssh-keysign helper instead.
1246          */
1247         sensitive_data.nkeys = 0;
1248         sensitive_data.keys = NULL;
1249         sensitive_data.external_keysign = 0;
1250         if (options.rhosts_rsa_authentication ||
1251             options.hostbased_authentication) {
1252                 sensitive_data.nkeys = 9;
1253                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
1254                     sizeof(Key));
1255                 for (i = 0; i < sensitive_data.nkeys; i++)
1256                         sensitive_data.keys[i] = NULL;
1257
1258                 PRIV_START;
1259 #if WITH_SSH1
1260                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
1261                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
1262 #endif
1263 #ifdef OPENSSL_HAS_ECC
1264                 sensitive_data.keys[1] = key_load_private_cert(KEY_ECDSA,
1265                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL);
1266 #endif
1267                 sensitive_data.keys[2] = key_load_private_cert(KEY_ED25519,
1268                     _PATH_HOST_ED25519_KEY_FILE, "", NULL);
1269                 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA,
1270                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
1271                 sensitive_data.keys[4] = key_load_private_cert(KEY_DSA,
1272                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
1273 #ifdef OPENSSL_HAS_ECC
1274                 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA,
1275                     _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL);
1276 #endif
1277                 sensitive_data.keys[6] = key_load_private_type(KEY_ED25519,
1278                     _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL);
1279                 sensitive_data.keys[7] = key_load_private_type(KEY_RSA,
1280                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
1281                 sensitive_data.keys[8] = key_load_private_type(KEY_DSA,
1282                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
1283                 PRIV_END;
1284
1285                 if (options.hostbased_authentication == 1 &&
1286                     sensitive_data.keys[0] == NULL &&
1287                     sensitive_data.keys[5] == NULL &&
1288                     sensitive_data.keys[6] == NULL &&
1289                     sensitive_data.keys[7] == NULL &&
1290                     sensitive_data.keys[8] == NULL) {
1291 #ifdef OPENSSL_HAS_ECC
1292                         sensitive_data.keys[1] = key_load_cert(
1293                             _PATH_HOST_ECDSA_KEY_FILE);
1294 #endif
1295                         sensitive_data.keys[2] = key_load_cert(
1296                             _PATH_HOST_ED25519_KEY_FILE);
1297                         sensitive_data.keys[3] = key_load_cert(
1298                             _PATH_HOST_RSA_KEY_FILE);
1299                         sensitive_data.keys[4] = key_load_cert(
1300                             _PATH_HOST_DSA_KEY_FILE);
1301 #ifdef OPENSSL_HAS_ECC
1302                         sensitive_data.keys[5] = key_load_public(
1303                             _PATH_HOST_ECDSA_KEY_FILE, NULL);
1304 #endif
1305                         sensitive_data.keys[6] = key_load_public(
1306                             _PATH_HOST_ED25519_KEY_FILE, NULL);
1307                         sensitive_data.keys[7] = key_load_public(
1308                             _PATH_HOST_RSA_KEY_FILE, NULL);
1309                         sensitive_data.keys[8] = key_load_public(
1310                             _PATH_HOST_DSA_KEY_FILE, NULL);
1311                         sensitive_data.external_keysign = 1;
1312                 }
1313         }
1314         /*
1315          * Get rid of any extra privileges that we may have.  We will no
1316          * longer need them.  Also, extra privileges could make it very hard
1317          * to read identity files and other non-world-readable files from the
1318          * user's home directory if it happens to be on a NFS volume where
1319          * root is mapped to nobody.
1320          */
1321         if (original_effective_uid == 0) {
1322                 PRIV_START;
1323                 permanently_set_uid(pw);
1324         }
1325
1326         /*
1327          * Now that we are back to our own permissions, create ~/.ssh
1328          * directory if it doesn't already exist.
1329          */
1330         if (config == NULL) {
1331                 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir,
1332                     strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
1333                 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) {
1334 #ifdef WITH_SELINUX
1335                         ssh_selinux_setfscreatecon(buf);
1336 #endif
1337                         if (mkdir(buf, 0700) < 0)
1338                                 error("Could not create directory '%.200s'.",
1339                                     buf);
1340 #ifdef WITH_SELINUX
1341                         ssh_selinux_setfscreatecon(NULL);
1342 #endif
1343                 }
1344         }
1345         /* load options.identity_files */
1346         load_public_identity_files();
1347
1348         /* Expand ~ in known host file names. */
1349         tilde_expand_paths(options.system_hostfiles,
1350             options.num_system_hostfiles);
1351         tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles);
1352
1353         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
1354         signal(SIGCHLD, main_sigchld_handler);
1355
1356         /* Log into the remote system.  Never returns if the login fails. */
1357         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
1358             options.port, pw, timeout_ms);
1359
1360         if (packet_connection_is_on_socket()) {
1361                 verbose("Authenticated to %s ([%s]:%d).", host,
1362                     get_remote_ipaddr(), get_remote_port());
1363         } else {
1364                 verbose("Authenticated to %s (via proxy).", host);
1365         }
1366
1367         /* We no longer need the private host keys.  Clear them now. */
1368         if (sensitive_data.nkeys != 0) {
1369                 for (i = 0; i < sensitive_data.nkeys; i++) {
1370                         if (sensitive_data.keys[i] != NULL) {
1371                                 /* Destroys contents safely */
1372                                 debug3("clear hostkey %d", i);
1373                                 key_free(sensitive_data.keys[i]);
1374                                 sensitive_data.keys[i] = NULL;
1375                         }
1376                 }
1377                 free(sensitive_data.keys);
1378         }
1379         for (i = 0; i < options.num_identity_files; i++) {
1380                 free(options.identity_files[i]);
1381                 options.identity_files[i] = NULL;
1382                 if (options.identity_keys[i]) {
1383                         key_free(options.identity_keys[i]);
1384                         options.identity_keys[i] = NULL;
1385                 }
1386         }
1387         for (i = 0; i < options.num_certificate_files; i++) {
1388                 free(options.certificate_files[i]);
1389                 options.certificate_files[i] = NULL;
1390         }
1391
1392         exit_status = compat20 ? ssh_session2() : ssh_session();
1393         packet_close();
1394
1395         if (options.control_path != NULL && muxserver_sock != -1)
1396                 unlink(options.control_path);
1397
1398         /* Kill ProxyCommand if it is running. */
1399         ssh_kill_proxy_command();
1400
1401         return exit_status;
1402 }
1403
1404 static void
1405 control_persist_detach(void)
1406 {
1407         pid_t pid;
1408         int devnull;
1409
1410         debug("%s: backgrounding master process", __func__);
1411
1412         /*
1413          * master (current process) into the background, and make the
1414          * foreground process a client of the backgrounded master.
1415          */
1416         switch ((pid = fork())) {
1417         case -1:
1418                 fatal("%s: fork: %s", __func__, strerror(errno));
1419         case 0:
1420                 /* Child: master process continues mainloop */
1421                 break;
1422         default:
1423                 /* Parent: set up mux slave to connect to backgrounded master */
1424                 debug2("%s: background process is %ld", __func__, (long)pid);
1425                 stdin_null_flag = ostdin_null_flag;
1426                 options.request_tty = orequest_tty;
1427                 tty_flag = otty_flag;
1428                 close(muxserver_sock);
1429                 muxserver_sock = -1;
1430                 options.control_master = SSHCTL_MASTER_NO;
1431                 muxclient(options.control_path);
1432                 /* muxclient() doesn't return on success. */
1433                 fatal("Failed to connect to new control master");
1434         }
1435         if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
1436                 error("%s: open(\"/dev/null\"): %s", __func__,
1437                     strerror(errno));
1438         } else {
1439                 if (dup2(devnull, STDIN_FILENO) == -1 ||
1440                     dup2(devnull, STDOUT_FILENO) == -1)
1441                         error("%s: dup2: %s", __func__, strerror(errno));
1442                 if (devnull > STDERR_FILENO)
1443                         close(devnull);
1444         }
1445         daemon(1, 1);
1446         setproctitle("%s [mux]", options.control_path);
1447 }
1448
1449 /* Do fork() after authentication. Used by "ssh -f" */
1450 static void
1451 fork_postauth(void)
1452 {
1453         if (need_controlpersist_detach)
1454                 control_persist_detach();
1455         debug("forking to background");
1456         fork_after_authentication_flag = 0;
1457         if (daemon(1, 1) < 0)
1458                 fatal("daemon() failed: %.200s", strerror(errno));
1459 }
1460
1461 /* Callback for remote forward global requests */
1462 static void
1463 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
1464 {
1465         struct Forward *rfwd = (struct Forward *)ctxt;
1466
1467         /* XXX verbose() on failure? */
1468         debug("remote forward %s for: listen %s%s%d, connect %s:%d",
1469             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1470             rfwd->listen_path ? rfwd->listen_path :
1471             rfwd->listen_host ? rfwd->listen_host : "",
1472             (rfwd->listen_path || rfwd->listen_host) ? ":" : "",
1473             rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
1474             rfwd->connect_host, rfwd->connect_port);
1475         if (rfwd->listen_path == NULL && rfwd->listen_port == 0) {
1476                 if (type == SSH2_MSG_REQUEST_SUCCESS) {
1477                         rfwd->allocated_port = packet_get_int();
1478                         logit("Allocated port %u for remote forward to %s:%d",
1479                             rfwd->allocated_port,
1480                             rfwd->connect_host, rfwd->connect_port);
1481                         channel_update_permitted_opens(rfwd->handle,
1482                             rfwd->allocated_port);
1483                 } else {
1484                         channel_update_permitted_opens(rfwd->handle, -1);
1485                 }
1486         }
1487
1488         if (type == SSH2_MSG_REQUEST_FAILURE) {
1489                 if (options.exit_on_forward_failure) {
1490                         if (rfwd->listen_path != NULL)
1491                                 fatal("Error: remote port forwarding failed "
1492                                     "for listen path %s", rfwd->listen_path);
1493                         else
1494                                 fatal("Error: remote port forwarding failed "
1495                                     "for listen port %d", rfwd->listen_port);
1496                 } else {
1497                         if (rfwd->listen_path != NULL)
1498                                 logit("Warning: remote port forwarding failed "
1499                                     "for listen path %s", rfwd->listen_path);
1500                         else
1501                                 logit("Warning: remote port forwarding failed "
1502                                     "for listen port %d", rfwd->listen_port);
1503                 }
1504         }
1505         if (++remote_forward_confirms_received == options.num_remote_forwards) {
1506                 debug("All remote forwarding requests processed");
1507                 if (fork_after_authentication_flag)
1508                         fork_postauth();
1509         }
1510 }
1511
1512 static void
1513 client_cleanup_stdio_fwd(int id, void *arg)
1514 {
1515         debug("stdio forwarding: done");
1516         cleanup_exit(0);
1517 }
1518
1519 static void
1520 ssh_stdio_confirm(int id, int success, void *arg)
1521 {
1522         if (!success)
1523                 fatal("stdio forwarding failed");
1524 }
1525
1526 static void
1527 ssh_init_stdio_forwarding(void)
1528 {
1529         Channel *c;
1530         int in, out;
1531
1532         if (stdio_forward_host == NULL)
1533                 return;
1534         if (!compat20)
1535                 fatal("stdio forwarding require Protocol 2");
1536
1537         debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port);
1538
1539         if ((in = dup(STDIN_FILENO)) < 0 ||
1540             (out = dup(STDOUT_FILENO)) < 0)
1541                 fatal("channel_connect_stdio_fwd: dup() in/out failed");
1542         if ((c = channel_connect_stdio_fwd(stdio_forward_host,
1543             stdio_forward_port, in, out)) == NULL)
1544                 fatal("%s: channel_connect_stdio_fwd failed", __func__);
1545         channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0);
1546         channel_register_open_confirm(c->self, ssh_stdio_confirm, NULL);
1547 }
1548
1549 static void
1550 ssh_init_forwarding(void)
1551 {
1552         int success = 0;
1553         int i;
1554
1555         /* Initiate local TCP/IP port forwardings. */
1556         for (i = 0; i < options.num_local_forwards; i++) {
1557                 debug("Local connections to %.200s:%d forwarded to remote "
1558                     "address %.200s:%d",
1559                     (options.local_forwards[i].listen_path != NULL) ?
1560                     options.local_forwards[i].listen_path :
1561                     (options.local_forwards[i].listen_host == NULL) ?
1562                     (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
1563                     options.local_forwards[i].listen_host,
1564                     options.local_forwards[i].listen_port,
1565                     (options.local_forwards[i].connect_path != NULL) ?
1566                     options.local_forwards[i].connect_path :
1567                     options.local_forwards[i].connect_host,
1568                     options.local_forwards[i].connect_port);
1569                 success += channel_setup_local_fwd_listener(
1570                     &options.local_forwards[i], &options.fwd_opts);
1571         }
1572         if (i > 0 && success != i && options.exit_on_forward_failure)
1573                 fatal("Could not request local forwarding.");
1574         if (i > 0 && success == 0)
1575                 error("Could not request local forwarding.");
1576
1577         /* Initiate remote TCP/IP port forwardings. */
1578         for (i = 0; i < options.num_remote_forwards; i++) {
1579                 debug("Remote connections from %.200s:%d forwarded to "
1580                     "local address %.200s:%d",
1581                     (options.remote_forwards[i].listen_path != NULL) ?
1582                     options.remote_forwards[i].listen_path :
1583                     (options.remote_forwards[i].listen_host == NULL) ?
1584                     "LOCALHOST" : options.remote_forwards[i].listen_host,
1585                     options.remote_forwards[i].listen_port,
1586                     (options.remote_forwards[i].connect_path != NULL) ?
1587                     options.remote_forwards[i].connect_path :
1588                     options.remote_forwards[i].connect_host,
1589                     options.remote_forwards[i].connect_port);
1590                 options.remote_forwards[i].handle =
1591                     channel_request_remote_forwarding(
1592                     &options.remote_forwards[i]);
1593                 if (options.remote_forwards[i].handle < 0) {
1594                         if (options.exit_on_forward_failure)
1595                                 fatal("Could not request remote forwarding.");
1596                         else
1597                                 logit("Warning: Could not request remote "
1598                                     "forwarding.");
1599                 } else {
1600                         client_register_global_confirm(ssh_confirm_remote_forward,
1601                             &options.remote_forwards[i]);
1602                 }
1603         }
1604
1605         /* Initiate tunnel forwarding. */
1606         if (options.tun_open != SSH_TUNMODE_NO) {
1607                 if (client_request_tun_fwd(options.tun_open,
1608                     options.tun_local, options.tun_remote) == -1) {
1609                         if (options.exit_on_forward_failure)
1610                                 fatal("Could not request tunnel forwarding.");
1611                         else
1612                                 error("Could not request tunnel forwarding.");
1613                 }
1614         }
1615 }
1616
1617 static void
1618 check_agent_present(void)
1619 {
1620         int r;
1621
1622         if (options.forward_agent) {
1623                 /* Clear agent forwarding if we don't have an agent. */
1624                 if ((r = ssh_get_authentication_socket(NULL)) != 0) {
1625                         options.forward_agent = 0;
1626                         if (r != SSH_ERR_AGENT_NOT_PRESENT)
1627                                 debug("ssh_get_authentication_socket: %s",
1628                                     ssh_err(r));
1629                 }
1630         }
1631 }
1632
1633 static int
1634 ssh_session(void)
1635 {
1636         int type;
1637         int interactive = 0;
1638         int have_tty = 0;
1639         struct winsize ws;
1640         char *cp;
1641         const char *display;
1642         char *proto = NULL, *data = NULL;
1643
1644         /* Enable compression if requested. */
1645         if (options.compression) {
1646                 debug("Requesting compression at level %d.",
1647                     options.compression_level);
1648
1649                 if (options.compression_level < 1 ||
1650                     options.compression_level > 9)
1651                         fatal("Compression level must be from 1 (fast) to "
1652                             "9 (slow, best).");
1653
1654                 /* Send the request. */
1655                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
1656                 packet_put_int(options.compression_level);
1657                 packet_send();
1658                 packet_write_wait();
1659                 type = packet_read();
1660                 if (type == SSH_SMSG_SUCCESS)
1661                         packet_start_compression(options.compression_level);
1662                 else if (type == SSH_SMSG_FAILURE)
1663                         logit("Warning: Remote host refused compression.");
1664                 else
1665                         packet_disconnect("Protocol error waiting for "
1666                             "compression response.");
1667         }
1668         /* Allocate a pseudo tty if appropriate. */
1669         if (tty_flag) {
1670                 debug("Requesting pty.");
1671
1672                 /* Start the packet. */
1673                 packet_start(SSH_CMSG_REQUEST_PTY);
1674
1675                 /* Store TERM in the packet.  There is no limit on the
1676                    length of the string. */
1677                 cp = getenv("TERM");
1678                 if (!cp)
1679                         cp = "";
1680                 packet_put_cstring(cp);
1681
1682                 /* Store window size in the packet. */
1683                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1684                         memset(&ws, 0, sizeof(ws));
1685                 packet_put_int((u_int)ws.ws_row);
1686                 packet_put_int((u_int)ws.ws_col);
1687                 packet_put_int((u_int)ws.ws_xpixel);
1688                 packet_put_int((u_int)ws.ws_ypixel);
1689
1690                 /* Store tty modes in the packet. */
1691                 tty_make_modes(fileno(stdin), NULL);
1692
1693                 /* Send the packet, and wait for it to leave. */
1694                 packet_send();
1695                 packet_write_wait();
1696
1697                 /* Read response from the server. */
1698                 type = packet_read();
1699                 if (type == SSH_SMSG_SUCCESS) {
1700                         interactive = 1;
1701                         have_tty = 1;
1702                 } else if (type == SSH_SMSG_FAILURE)
1703                         logit("Warning: Remote host failed or refused to "
1704                             "allocate a pseudo tty.");
1705                 else
1706                         packet_disconnect("Protocol error waiting for pty "
1707                             "request response.");
1708         }
1709         /* Request X11 forwarding if enabled and DISPLAY is set. */
1710         display = getenv("DISPLAY");
1711         if (display == NULL && options.forward_x11)
1712                 debug("X11 forwarding requested but DISPLAY not set");
1713         if (options.forward_x11 && client_x11_get_proto(display,
1714             options.xauth_location, options.forward_x11_trusted,
1715             options.forward_x11_timeout, &proto, &data) == 0) {
1716                 /* Request forwarding with authentication spoofing. */
1717                 debug("Requesting X11 forwarding with authentication "
1718                     "spoofing.");
1719                 x11_request_forwarding_with_spoofing(0, display, proto,
1720                     data, 0);
1721                 /* Read response from the server. */
1722                 type = packet_read();
1723                 if (type == SSH_SMSG_SUCCESS) {
1724                         interactive = 1;
1725                 } else if (type == SSH_SMSG_FAILURE) {
1726                         logit("Warning: Remote host denied X11 forwarding.");
1727                 } else {
1728                         packet_disconnect("Protocol error waiting for X11 "
1729                             "forwarding");
1730                 }
1731         }
1732         /* Tell the packet module whether this is an interactive session. */
1733         packet_set_interactive(interactive,
1734             options.ip_qos_interactive, options.ip_qos_bulk);
1735
1736         /* Request authentication agent forwarding if appropriate. */
1737         check_agent_present();
1738
1739         if (options.forward_agent) {
1740                 debug("Requesting authentication agent forwarding.");
1741                 auth_request_forwarding();
1742
1743                 /* Read response from the server. */
1744                 type = packet_read();
1745                 packet_check_eom();
1746                 if (type != SSH_SMSG_SUCCESS)
1747                         logit("Warning: Remote host denied authentication agent forwarding.");
1748         }
1749
1750         /* Initiate port forwardings. */
1751         ssh_init_stdio_forwarding();
1752         ssh_init_forwarding();
1753
1754         /* Execute a local command */
1755         if (options.local_command != NULL &&
1756             options.permit_local_command)
1757                 ssh_local_cmd(options.local_command);
1758
1759         /*
1760          * If requested and we are not interested in replies to remote
1761          * forwarding requests, then let ssh continue in the background.
1762          */
1763         if (fork_after_authentication_flag) {
1764                 if (options.exit_on_forward_failure &&
1765                     options.num_remote_forwards > 0) {
1766                         debug("deferring postauth fork until remote forward "
1767                             "confirmation received");
1768                 } else
1769                         fork_postauth();
1770         }
1771
1772         /*
1773          * If a command was specified on the command line, execute the
1774          * command now. Otherwise request the server to start a shell.
1775          */
1776         if (buffer_len(&command) > 0) {
1777                 int len = buffer_len(&command);
1778                 if (len > 900)
1779                         len = 900;
1780                 debug("Sending command: %.*s", len,
1781                     (u_char *)buffer_ptr(&command));
1782                 packet_start(SSH_CMSG_EXEC_CMD);
1783                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1784                 packet_send();
1785                 packet_write_wait();
1786         } else {
1787                 debug("Requesting shell.");
1788                 packet_start(SSH_CMSG_EXEC_SHELL);
1789                 packet_send();
1790                 packet_write_wait();
1791         }
1792
1793         /* Enter the interactive session. */
1794         return client_loop(have_tty, tty_flag ?
1795             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1796 }
1797
1798 /* request pty/x11/agent/tcpfwd/shell for channel */
1799 static void
1800 ssh_session2_setup(int id, int success, void *arg)
1801 {
1802         extern char **environ;
1803         const char *display;
1804         int interactive = tty_flag;
1805         char *proto = NULL, *data = NULL;
1806
1807         if (!success)
1808                 return; /* No need for error message, channels code sens one */
1809
1810         display = getenv("DISPLAY");
1811         if (display == NULL && options.forward_x11)
1812                 debug("X11 forwarding requested but DISPLAY not set");
1813         if (options.forward_x11 && client_x11_get_proto(display,
1814             options.xauth_location, options.forward_x11_trusted,
1815             options.forward_x11_timeout, &proto, &data) == 0) {
1816                 /* Request forwarding with authentication spoofing. */
1817                 debug("Requesting X11 forwarding with authentication "
1818                     "spoofing.");
1819                 x11_request_forwarding_with_spoofing(id, display, proto,
1820                     data, 1);
1821                 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1822                 /* XXX exit_on_forward_failure */
1823                 interactive = 1;
1824         }
1825
1826         check_agent_present();
1827         if (options.forward_agent) {
1828                 debug("Requesting authentication agent forwarding.");
1829                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1830                 packet_send();
1831         }
1832
1833         /* Tell the packet module whether this is an interactive session. */
1834         packet_set_interactive(interactive,
1835             options.ip_qos_interactive, options.ip_qos_bulk);
1836
1837         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1838             NULL, fileno(stdin), &command, environ);
1839 }
1840
1841 /* open new channel for a session */
1842 static int
1843 ssh_session2_open(void)
1844 {
1845         Channel *c;
1846         int window, packetmax, in, out, err;
1847
1848         if (stdin_null_flag) {
1849                 in = open(_PATH_DEVNULL, O_RDONLY);
1850         } else {
1851                 in = dup(STDIN_FILENO);
1852         }
1853         out = dup(STDOUT_FILENO);
1854         err = dup(STDERR_FILENO);
1855
1856         if (in < 0 || out < 0 || err < 0)
1857                 fatal("dup() in/out/err failed");
1858
1859         /* enable nonblocking unless tty */
1860         if (!isatty(in))
1861                 set_nonblock(in);
1862         if (!isatty(out))
1863                 set_nonblock(out);
1864         if (!isatty(err))
1865                 set_nonblock(err);
1866
1867         window = CHAN_SES_WINDOW_DEFAULT;
1868         packetmax = CHAN_SES_PACKET_DEFAULT;
1869         if (tty_flag) {
1870                 window >>= 1;
1871                 packetmax >>= 1;
1872         }
1873         c = channel_new(
1874             "session", SSH_CHANNEL_OPENING, in, out, err,
1875             window, packetmax, CHAN_EXTENDED_WRITE,
1876             "client-session", /*nonblock*/0);
1877
1878         debug3("ssh_session2_open: channel_new: %d", c->self);
1879
1880         channel_send_open(c->self);
1881         if (!no_shell_flag)
1882                 channel_register_open_confirm(c->self,
1883                     ssh_session2_setup, NULL);
1884
1885         return c->self;
1886 }
1887
1888 static int
1889 ssh_session2(void)
1890 {
1891         int id = -1;
1892
1893         /* XXX should be pre-session */
1894         if (!options.control_persist)
1895                 ssh_init_stdio_forwarding();
1896         ssh_init_forwarding();
1897
1898         /* Start listening for multiplex clients */
1899         muxserver_listen();
1900
1901         /*
1902          * If we are in control persist mode and have a working mux listen
1903          * socket, then prepare to background ourselves and have a foreground
1904          * client attach as a control slave.
1905          * NB. we must save copies of the flags that we override for
1906          * the backgrounding, since we defer attachment of the slave until
1907          * after the connection is fully established (in particular,
1908          * async rfwd replies have been received for ExitOnForwardFailure).
1909          */
1910         if (options.control_persist && muxserver_sock != -1) {
1911                 ostdin_null_flag = stdin_null_flag;
1912                 ono_shell_flag = no_shell_flag;
1913                 orequest_tty = options.request_tty;
1914                 otty_flag = tty_flag;
1915                 stdin_null_flag = 1;
1916                 no_shell_flag = 1;
1917                 tty_flag = 0;
1918                 if (!fork_after_authentication_flag)
1919                         need_controlpersist_detach = 1;
1920                 fork_after_authentication_flag = 1;
1921         }
1922         /*
1923          * ControlPersist mux listen socket setup failed, attempt the
1924          * stdio forward setup that we skipped earlier.
1925          */
1926         if (options.control_persist && muxserver_sock == -1)
1927                 ssh_init_stdio_forwarding();
1928
1929         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1930                 id = ssh_session2_open();
1931         else {
1932                 packet_set_interactive(
1933                     options.control_master == SSHCTL_MASTER_NO,
1934                     options.ip_qos_interactive, options.ip_qos_bulk);
1935         }
1936
1937         /* If we don't expect to open a new session, then disallow it */
1938         if (options.control_master == SSHCTL_MASTER_NO &&
1939             (datafellows & SSH_NEW_OPENSSH)) {
1940                 debug("Requesting no-more-sessions@openssh.com");
1941                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
1942                 packet_put_cstring("no-more-sessions@openssh.com");
1943                 packet_put_char(0);
1944                 packet_send();
1945         }
1946
1947         /* Execute a local command */
1948         if (options.local_command != NULL &&
1949             options.permit_local_command)
1950                 ssh_local_cmd(options.local_command);
1951
1952         /*
1953          * If requested and we are not interested in replies to remote
1954          * forwarding requests, then let ssh continue in the background.
1955          */
1956         if (fork_after_authentication_flag) {
1957                 if (options.exit_on_forward_failure &&
1958                     options.num_remote_forwards > 0) {
1959                         debug("deferring postauth fork until remote forward "
1960                             "confirmation received");
1961                 } else
1962                         fork_postauth();
1963         }
1964
1965         return client_loop(tty_flag, tty_flag ?
1966             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1967 }
1968
1969 /* Loads all IdentityFile and CertificateFile keys */
1970 static void
1971 load_public_identity_files(void)
1972 {
1973         char *filename, *cp, thishost[NI_MAXHOST];
1974         char *pwdir = NULL, *pwname = NULL;
1975         Key *public;
1976         struct passwd *pw;
1977         int i;
1978         u_int n_ids, n_certs;
1979         char *identity_files[SSH_MAX_IDENTITY_FILES];
1980         Key *identity_keys[SSH_MAX_IDENTITY_FILES];
1981         char *certificate_files[SSH_MAX_CERTIFICATE_FILES];
1982         struct sshkey *certificates[SSH_MAX_CERTIFICATE_FILES];
1983 #ifdef ENABLE_PKCS11
1984         Key **keys;
1985         int nkeys;
1986 #endif /* PKCS11 */
1987
1988         n_ids = n_certs = 0;
1989         memset(identity_files, 0, sizeof(identity_files));
1990         memset(identity_keys, 0, sizeof(identity_keys));
1991         memset(certificate_files, 0, sizeof(certificate_files));
1992         memset(certificates, 0, sizeof(certificates));
1993
1994 #ifdef ENABLE_PKCS11
1995         if (options.pkcs11_provider != NULL &&
1996             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1997             (pkcs11_init(!options.batch_mode) == 0) &&
1998             (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL,
1999             &keys)) > 0) {
2000                 for (i = 0; i < nkeys; i++) {
2001                         if (n_ids >= SSH_MAX_IDENTITY_FILES) {
2002                                 key_free(keys[i]);
2003                                 continue;
2004                         }
2005                         identity_keys[n_ids] = keys[i];
2006                         identity_files[n_ids] =
2007                             xstrdup(options.pkcs11_provider); /* XXX */
2008                         n_ids++;
2009                 }
2010                 free(keys);
2011         }
2012 #endif /* ENABLE_PKCS11 */
2013         if ((pw = getpwuid(original_real_uid)) == NULL)
2014                 fatal("load_public_identity_files: getpwuid failed");
2015         pwname = xstrdup(pw->pw_name);
2016         pwdir = xstrdup(pw->pw_dir);
2017         if (gethostname(thishost, sizeof(thishost)) == -1)
2018                 fatal("load_public_identity_files: gethostname: %s",
2019                     strerror(errno));
2020         for (i = 0; i < options.num_identity_files; i++) {
2021                 if (n_ids >= SSH_MAX_IDENTITY_FILES ||
2022                     strcasecmp(options.identity_files[i], "none") == 0) {
2023                         free(options.identity_files[i]);
2024                         options.identity_files[i] = NULL;
2025                         continue;
2026                 }
2027                 cp = tilde_expand_filename(options.identity_files[i],
2028                     original_real_uid);
2029                 filename = percent_expand(cp, "d", pwdir,
2030                     "u", pwname, "l", thishost, "h", host,
2031                     "r", options.user, (char *)NULL);
2032                 free(cp);
2033                 public = key_load_public(filename, NULL);
2034                 debug("identity file %s type %d", filename,
2035                     public ? public->type : -1);
2036                 free(options.identity_files[i]);
2037                 identity_files[n_ids] = filename;
2038                 identity_keys[n_ids] = public;
2039
2040                 if (++n_ids >= SSH_MAX_IDENTITY_FILES)
2041                         continue;
2042
2043                 /*
2044                  * If no certificates have been explicitly listed then try
2045                  * to add the default certificate variant too.
2046                  */
2047                 if (options.num_certificate_files != 0)
2048                         continue;
2049                 xasprintf(&cp, "%s-cert", filename);
2050                 public = key_load_public(cp, NULL);
2051                 debug("identity file %s type %d", cp,
2052                     public ? public->type : -1);
2053                 if (public == NULL) {
2054                         free(cp);
2055                         continue;
2056                 }
2057                 if (!key_is_cert(public)) {
2058                         debug("%s: key %s type %s is not a certificate",
2059                             __func__, cp, key_type(public));
2060                         key_free(public);
2061                         free(cp);
2062                         continue;
2063                 }
2064                 identity_keys[n_ids] = public;
2065                 identity_files[n_ids] = cp;
2066                 n_ids++;
2067         }
2068
2069         if (options.num_certificate_files > SSH_MAX_CERTIFICATE_FILES)
2070                 fatal("%s: too many certificates", __func__);
2071         for (i = 0; i < options.num_certificate_files; i++) {
2072                 cp = tilde_expand_filename(options.certificate_files[i],
2073                     original_real_uid);
2074                 filename = percent_expand(cp, "d", pwdir,
2075                     "u", pwname, "l", thishost, "h", host,
2076                     "r", options.user, (char *)NULL);
2077                 free(cp);
2078
2079                 public = key_load_public(filename, NULL);
2080                 debug("certificate file %s type %d", filename,
2081                     public ? public->type : -1);
2082                 free(options.certificate_files[i]);
2083                 options.certificate_files[i] = NULL;
2084                 if (public == NULL) {
2085                         free(filename);
2086                         continue;
2087                 }
2088                 if (!key_is_cert(public)) {
2089                         debug("%s: key %s type %s is not a certificate",
2090                             __func__, filename, key_type(public));
2091                         key_free(public);
2092                         free(filename);
2093                         continue;
2094                 }
2095                 certificate_files[n_certs] = filename;
2096                 certificates[n_certs] = public;
2097                 ++n_certs;
2098         }
2099
2100         options.num_identity_files = n_ids;
2101         memcpy(options.identity_files, identity_files, sizeof(identity_files));
2102         memcpy(options.identity_keys, identity_keys, sizeof(identity_keys));
2103
2104         options.num_certificate_files = n_certs;
2105         memcpy(options.certificate_files,
2106             certificate_files, sizeof(certificate_files));
2107         memcpy(options.certificates, certificates, sizeof(certificates));
2108
2109         explicit_bzero(pwname, strlen(pwname));
2110         free(pwname);
2111         explicit_bzero(pwdir, strlen(pwdir));
2112         free(pwdir);
2113 }
2114
2115 static void
2116 main_sigchld_handler(int sig)
2117 {
2118         int save_errno = errno;
2119         pid_t pid;
2120         int status;
2121
2122         while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
2123             (pid < 0 && errno == EINTR))
2124                 ;
2125
2126         signal(sig, main_sigchld_handler);
2127         errno = save_errno;
2128 }