ssh.c

   1 /*
   2  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   3  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   4  *                    All rights reserved
   5  * Ssh client program.  This program can be used to log into a remote machine.
   6  * The software supports strong authentication, encryption, and forwarding
   7  * of X11, TCP/IP, and authentication connections.
   8  *
   9  * As far as I am concerned, the code I have written for this software
  10  * can be used freely for any purpose.  Any derived versions of this
  11  * software must be clearly marked as such, and if the derived work is
  12  * incompatible with the protocol description in the RFC file, it must be
  13  * called by a name other than "ssh" or "Secure Shell".
  14  *
  15  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  16  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  17  *
  18  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
  19  * in Canada (German citizen).
  20  *
  21  * Redistribution and use in source and binary forms, with or without
  22  * modification, are permitted provided that the following conditions
  23  * are met:
  24  * 1. Redistributions of source code must retain the above copyright
  25  *    notice, this list of conditions and the following disclaimer.
  26  * 2. Redistributions in binary form must reproduce the above copyright
  27  *    notice, this list of conditions and the following disclaimer in the
  28  *    documentation and/or other materials provided with the distribution.
  29  *
  30  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  31  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  32  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  33  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  34  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  35  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  36  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  37  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  38  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  39  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  40  */
  41
  42 #include "includes.h"
  43 RCSID("$OpenBSD: ssh.c,v 1.243 2005/06/16 03:38:36 djm Exp $");
  44
  45 #include <openssl/evp.h>
  46 #include <openssl/err.h>
  47
  48 #include "ssh.h"
  49 #include "ssh1.h"
  50 #include "ssh2.h"
  51 #include "compat.h"
  52 #include "cipher.h"
  53 #include "xmalloc.h"
  54 #include "packet.h"
  55 #include "buffer.h"
  56 #include "bufaux.h"
  57 #include "channels.h"
  58 #include "key.h"
  59 #include "authfd.h"
  60 #include "authfile.h"
  61 #include "pathnames.h"
  62 #include "dispatch.h"
  63 #include "clientloop.h"
  64 #include "log.h"
  65 #include "readconf.h"
  66 #include "sshconnect.h"
  67 #include "misc.h"
  68 #include "kex.h"
  69 #include "mac.h"
  70 #include "sshpty.h"
  71 #include "match.h"
  72 #include "msg.h"
  73 #include "monitor_fdpass.h"
  74 #include "uidswap.h"
  75
  76 #ifdef SMARTCARD
  77 #include "scard.h"
  78 #endif
  79
  80 extern char *__progname;
  81
  82 /* Flag indicating whether debug mode is on.  This can be set on the command line. */
  83 int debug_flag = 0;
  84
  85 /* Flag indicating whether a tty should be allocated */
  86 int tty_flag = 0;
  87 int no_tty_flag = 0;
  88 int force_tty_flag = 0;
  89
  90 /* don't exec a shell */
  91 int no_shell_flag = 0;
  92
  93 /*
  94  * Flag indicating that nothing should be read from stdin.  This can be set
  95  * on the command line.
  96  */
  97 int stdin_null_flag = 0;
  98
  99 /*
 100  * Flag indicating that ssh should fork after authentication.  This is useful
 101  * so that the passphrase can be entered manually, and then ssh goes to the
 102  * background.
 103  */
 104 int fork_after_authentication_flag = 0;
 105
 106 /*
 107  * General data structure for command line options and options configurable
 108  * in configuration files.  See readconf.h.
 109  */
 110 Options options;
 111
 112 /* optional user configfile */
 113 char *config = NULL;
 114
 115 /*
 116  * Name of the host we are connecting to.  This is the name given on the
 117  * command line, or the HostName specified for the user-supplied name in a
 118  * configuration file.
 119  */
 120 char *host;
 121
 122 /* socket address the host resolves to */
 123 struct sockaddr_storage hostaddr;
 124
 125 /* Private host keys. */
 126 Sensitive sensitive_data;
 127
 128 /* Original real UID. */
 129 uid_t original_real_uid;
 130 uid_t original_effective_uid;
 131
 132 /* command to be executed */
 133 Buffer command;
 134
 135 /* Should we execute a command or invoke a subsystem? */
 136 int subsystem_flag = 0;
 137
 138 /* # of replies received for global requests */
 139 static int client_global_request_id = 0;
 140
 141 /* pid of proxycommand child process */
 142 pid_t proxy_command_pid = 0;
 143
 144 /* fd to control socket */
 145 int control_fd = -1;
 146
 147 /* Multiplexing control command */
 148 static u_int mux_command = 0;
 149
 150 /* Only used in control client mode */
 151 volatile sig_atomic_t control_client_terminate = 0;
 152 u_int control_server_pid = 0;
 153
 154 /* Prints a help message to the user.  This function never returns. */
 155
 156 static void
 157 usage(void)
 158 {
 159         fprintf(stderr,
 160 "usage: ssh [-1246AaCfgkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
 161 "           [-D port] [-e escape_char] [-F configfile]\n"
 162 "           [-i identity_file] [-L [bind_address:]port:host:hostport]\n"
 163 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 164 "           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
 165 "           [user@]hostname [command]\n"
 166         );
 167         exit(1);
 168 }
 169
 170 static int ssh_session(void);
 171 static int ssh_session2(void);
 172 static void load_public_identity_files(void);
 173 static void control_client(const char *path);
 174
 175 /*
 176  * Main program for the ssh client.
 177  */
 178 int
 179 main(int ac, char **av)
 180 {
 181         int i, opt, exit_status;
 182         char *p, *cp, *line, buf[256];
 183         struct stat st;
 184         struct passwd *pw;
 185         int dummy;
 186         extern int optind, optreset;
 187         extern char *optarg;
 188         Forward fwd;
 189
 190         __progname = ssh_get_progname(av[0]);
 191         init_rng();
 192
 193         /*
 194          * Save the original real uid.  It will be needed later (uid-swapping
 195          * may clobber the real uid).
 196          */
 197         original_real_uid = getuid();
 198         original_effective_uid = geteuid();
 199
 200         /*
 201          * Use uid-swapping to give up root privileges for the duration of
 202          * option processing.  We will re-instantiate the rights when we are
 203          * ready to create the privileged port, and will permanently drop
 204          * them when the port has been created (actually, when the connection
 205          * has been made, as we may need to create the port several times).
 206          */
 207         PRIV_END;
 208
 209 #ifdef HAVE_SETRLIMIT
 210         /* If we are installed setuid root be careful to not drop core. */
 211         if (original_real_uid != original_effective_uid) {
 212                 struct rlimit rlim;
 213                 rlim.rlim_cur = rlim.rlim_max = 0;
 214                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 215                         fatal("setrlimit failed: %.100s", strerror(errno));
 216         }
 217 #endif
 218         /* Get user data. */
 219         pw = getpwuid(original_real_uid);
 220         if (!pw) {
 221                 logit("You don't exist, go away!");
 222                 exit(1);
 223         }
 224         /* Take a copy of the returned structure. */
 225         pw = pwcopy(pw);
 226
 227         /*
 228          * Set our umask to something reasonable, as some files are created
 229          * with the default umask.  This will make them world-readable but
 230          * writable only by the owner, which is ok for all files for which we
 231          * don't set the modes explicitly.
 232          */
 233         umask(022);
 234
 235         /* Initialize option structure to indicate that no values have been set. */
 236         initialize_options(&options);
 237
 238         /* Parse command-line arguments. */
 239         host = NULL;
 240
 241 again:
 242         while ((opt = getopt(ac, av,
 243             "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNO:PR:S:TVXY")) != -1) {
 244                 switch (opt) {
 245                 case '1':
 246                         options.protocol = SSH_PROTO_1;
 247                         break;
 248                 case '2':
 249                         options.protocol = SSH_PROTO_2;
 250                         break;
 251                 case '4':
 252                         options.address_family = AF_INET;
 253                         break;
 254                 case '6':
 255                         options.address_family = AF_INET6;
 256                         break;
 257                 case 'n':
 258                         stdin_null_flag = 1;
 259                         break;
 260                 case 'f':
 261                         fork_after_authentication_flag = 1;
 262                         stdin_null_flag = 1;
 263                         break;
 264                 case 'x':
 265                         options.forward_x11 = 0;
 266                         break;
 267                 case 'X':
 268                         options.forward_x11 = 1;
 269                         break;
 270                 case 'Y':
 271                         options.forward_x11 = 1;
 272                         options.forward_x11_trusted = 1;
 273                         break;
 274                 case 'g':
 275                         options.gateway_ports = 1;
 276                         break;
 277                 case 'O':
 278                         if (strcmp(optarg, "check") == 0)
 279                                 mux_command = SSHMUX_COMMAND_ALIVE_CHECK;
 280                         else if (strcmp(optarg, "exit") == 0)
 281                                 mux_command = SSHMUX_COMMAND_TERMINATE;
 282                         else
 283                                 fatal("Invalid multiplex command.");
 284                         break;
 285                 case 'P':       /* deprecated */
 286                         options.use_privileged_port = 0;
 287                         break;
 288                 case 'a':
 289                         options.forward_agent = 0;
 290                         break;
 291                 case 'A':
 292                         options.forward_agent = 1;
 293                         break;
 294                 case 'k':
 295                         options.gss_deleg_creds = 0;
 296                         break;
 297                 case 'i':
 298                         if (stat(optarg, &st) < 0) {
 299                                 fprintf(stderr, "Warning: Identity file %s "
 300                                     "not accessible: %s.\n", optarg,
 301                                     strerror(errno));
 302                                 break;
 303                         }
 304                         if (options.num_identity_files >=
 305                             SSH_MAX_IDENTITY_FILES)
 306                                 fatal("Too many identity files specified "
 307                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
 308                         options.identity_files[options.num_identity_files++] =
 309                             xstrdup(optarg);
 310                         break;
 311                 case 'I':
 312 #ifdef SMARTCARD
 313                         options.smartcard_device = xstrdup(optarg);
 314 #else
 315                         fprintf(stderr, "no support for smartcards.\n");
 316 #endif
 317                         break;
 318                 case 't':
 319                         if (tty_flag)
 320                                 force_tty_flag = 1;
 321                         tty_flag = 1;
 322                         break;
 323                 case 'v':
 324                         if (debug_flag == 0) {
 325                                 debug_flag = 1;
 326                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 327                         } else {
 328                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 329                                         options.log_level++;
 330                                 break;
 331                         }
 332                         /* FALLTHROUGH */
 333                 case 'V':
 334                         fprintf(stderr, "%s, %s\n",
 335                             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
 336                         if (opt == 'V')
 337                                 exit(0);
 338                         break;
 339                 case 'q':
 340                         options.log_level = SYSLOG_LEVEL_QUIET;
 341                         break;
 342                 case 'e':
 343                         if (optarg[0] == '^' && optarg[2] == 0 &&
 344                             (u_char) optarg[1] >= 64 &&
 345                             (u_char) optarg[1] < 128)
 346                                 options.escape_char = (u_char) optarg[1] & 31;
 347                         else if (strlen(optarg) == 1)
 348                                 options.escape_char = (u_char) optarg[0];
 349                         else if (strcmp(optarg, "none") == 0)
 350                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 351                         else {
 352                                 fprintf(stderr, "Bad escape character '%s'.\n",
 353                                     optarg);
 354                                 exit(1);
 355                         }
 356                         break;
 357                 case 'c':
 358                         if (ciphers_valid(optarg)) {
 359                                 /* SSH2 only */
 360                                 options.ciphers = xstrdup(optarg);
 361                                 options.cipher = SSH_CIPHER_INVALID;
 362                         } else {
 363                                 /* SSH1 only */
 364                                 options.cipher = cipher_number(optarg);
 365                                 if (options.cipher == -1) {
 366                                         fprintf(stderr,
 367                                             "Unknown cipher type '%s'\n",
 368                                             optarg);
 369                                         exit(1);
 370                                 }
 371                                 if (options.cipher == SSH_CIPHER_3DES)
 372                                         options.ciphers = "3des-cbc";
 373                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 374                                         options.ciphers = "blowfish-cbc";
 375                                 else
 376                                         options.ciphers = (char *)-1;
 377                         }
 378                         break;
 379                 case 'm':
 380                         if (mac_valid(optarg))
 381                                 options.macs = xstrdup(optarg);
 382                         else {
 383                                 fprintf(stderr, "Unknown mac type '%s'\n",
 384                                     optarg);
 385                                 exit(1);
 386                         }
 387                         break;
 388                 case 'M':
 389                         if (options.control_master == SSHCTL_MASTER_YES)
 390                                 options.control_master = SSHCTL_MASTER_ASK;
 391                         else
 392                                 options.control_master = SSHCTL_MASTER_YES;
 393                         break;
 394                 case 'p':
 395                         options.port = a2port(optarg);
 396                         if (options.port == 0) {
 397                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 398                                 exit(1);
 399                         }
 400                         break;
 401                 case 'l':
 402                         options.user = optarg;
 403                         break;
 404
 405                 case 'L':
 406                         if (parse_forward(&fwd, optarg))
 407                                 add_local_forward(&options, &fwd);
 408                         else {
 409                                 fprintf(stderr,
 410                                     "Bad local forwarding specification '%s'\n",
 411                                     optarg);
 412                                 exit(1);
 413                         }
 414                         break;
 415
 416                 case 'R':
 417                         if (parse_forward(&fwd, optarg)) {
 418                                 add_remote_forward(&options, &fwd);
 419                         } else {
 420                                 fprintf(stderr,
 421                                     "Bad remote forwarding specification "
 422                                     "'%s'\n", optarg);
 423                                 exit(1);
 424                         }
 425                         break;
 426
 427                 case 'D':
 428                         cp = p = xstrdup(optarg);
 429                         memset(&fwd, '\0', sizeof(fwd));
 430                         fwd.connect_host = "socks";
 431                         if ((fwd.listen_host = hpdelim(&cp)) == NULL) {
 432                                 fprintf(stderr, "Bad dynamic forwarding "
 433                                     "specification '%.100s'\n", optarg);
 434                                 exit(1);
 435                         }
 436                         if (cp != NULL) {
 437                                 fwd.listen_port = a2port(cp);
 438                                 fwd.listen_host = cleanhostname(fwd.listen_host);
 439                         } else {
 440                                 fwd.listen_port = a2port(fwd.listen_host);
 441                                 fwd.listen_host = "";
 442                         }
 443
 444                         if (fwd.listen_port == 0) {
 445                                 fprintf(stderr, "Bad dynamic port '%s'\n",
 446                                     optarg);
 447                                 exit(1);
 448                         }
 449                         add_local_forward(&options, &fwd);
 450                         xfree(p);
 451                         break;
 452
 453                 case 'C':
 454                         options.compression = 1;
 455                         break;
 456                 case 'N':
 457                         no_shell_flag = 1;
 458                         no_tty_flag = 1;
 459                         break;
 460                 case 'T':
 461                         no_tty_flag = 1;
 462                         break;
 463                 case 'o':
 464                         dummy = 1;
 465                         line = xstrdup(optarg);
 466                         if (process_config_line(&options, host ? host : "",
 467                             line, "command-line", 0, &dummy) != 0)
 468                                 exit(1);
 469                         xfree(line);
 470                         break;
 471                 case 's':
 472                         subsystem_flag = 1;
 473                         break;
 474                 case 'S':
 475                         if (options.control_path != NULL)
 476                                 free(options.control_path);
 477                         options.control_path = xstrdup(optarg);
 478                         break;
 479                 case 'b':
 480                         options.bind_address = optarg;
 481                         break;
 482                 case 'F':
 483                         config = optarg;
 484                         break;
 485                 default:
 486                         usage();
 487                 }
 488         }
 489
 490         ac -= optind;
 491         av += optind;
 492
 493         if (ac > 0 && !host && **av != '-') {
 494                 if (strrchr(*av, '@')) {
 495                         p = xstrdup(*av);
 496                         cp = strrchr(p, '@');
 497                         if (cp == NULL || cp == p)
 498                                 usage();
 499                         options.user = p;
 500                         *cp = '\0';
 501                         host = ++cp;
 502                 } else
 503                         host = *av;
 504                 if (ac > 1) {
 505                         optind = optreset = 1;
 506                         goto again;
 507                 }
 508                 ac--, av++;
 509         }
 510
 511         /* Check that we got a host name. */
 512         if (!host)
 513                 usage();
 514
 515         SSLeay_add_all_algorithms();
 516         ERR_load_crypto_strings();
 517
 518         /* Initialize the command to execute on remote host. */
 519         buffer_init(&command);
 520
 521         /*
 522          * Save the command to execute on the remote host in a buffer. There
 523          * is no limit on the length of the command, except by the maximum
 524          * packet size.  Also sets the tty flag if there is no command.
 525          */
 526         if (!ac) {
 527                 /* No command specified - execute shell on a tty. */
 528                 tty_flag = 1;
 529                 if (subsystem_flag) {
 530                         fprintf(stderr,
 531                             "You must specify a subsystem to invoke.\n");
 532                         usage();
 533                 }
 534         } else {
 535                 /* A command has been specified.  Store it into the buffer. */
 536                 for (i = 0; i < ac; i++) {
 537                         if (i)
 538                                 buffer_append(&command, " ", 1);
 539                         buffer_append(&command, av[i], strlen(av[i]));
 540                 }
 541         }
 542
 543         /* Cannot fork to background if no command. */
 544         if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
 545                 fatal("Cannot fork into background without a command to execute.");
 546
 547         /* Allocate a tty by default if no command specified. */
 548         if (buffer_len(&command) == 0)
 549                 tty_flag = 1;
 550
 551         /* Force no tty */
 552         if (no_tty_flag)
 553                 tty_flag = 0;
 554         /* Do not allocate a tty if stdin is not a tty. */
 555         if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
 556                 if (tty_flag)
 557                         logit("Pseudo-terminal will not be allocated because stdin is not a terminal.");
 558                 tty_flag = 0;
 559         }
 560
 561         /*
 562          * Initialize "log" output.  Since we are the client all output
 563          * actually goes to stderr.
 564          */
 565         log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 566             SYSLOG_FACILITY_USER, 1);
 567
 568         /*
 569          * Read per-user configuration file.  Ignore the system wide config
 570          * file if the user specifies a config file on the command line.
 571          */
 572         if (config != NULL) {
 573                 if (!read_config_file(config, host, &options, 0))
 574                         fatal("Can't open user config file %.100s: "
 575                             "%.100s", config, strerror(errno));
 576         } else  {
 577                 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
 578                     _PATH_SSH_USER_CONFFILE);
 579                 (void)read_config_file(buf, host, &options, 1);
 580
 581                 /* Read systemwide configuration file after use config. */
 582                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
 583                     &options, 0);
 584         }
 585
 586         /* Fill configuration defaults. */
 587         fill_default_options(&options);
 588
 589         channel_set_af(options.address_family);
 590
 591         /* reinit */
 592         log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
 593
 594         seed_rng();
 595
 596         if (options.user == NULL)
 597                 options.user = xstrdup(pw->pw_name);
 598
 599         if (options.hostname != NULL)
 600                 host = options.hostname;
 601
 602         /* force lowercase for hostkey matching */
 603         if (options.host_key_alias != NULL) {
 604                 for (p = options.host_key_alias; *p; p++)
 605                         if (isupper(*p))
 606                                 *p = tolower(*p);
 607         }
 608
 609         if (options.proxy_command != NULL &&
 610             strcmp(options.proxy_command, "none") == 0)
 611                 options.proxy_command = NULL;
 612
 613         if (options.control_path != NULL) {
 614                 snprintf(buf, sizeof(buf), "%d", options.port);
 615                 cp = tilde_expand_filename(options.control_path,
 616                     original_real_uid);
 617                 options.control_path = percent_expand(cp, "p", buf, "h", host,
 618                     "r", options.user, (char *)NULL);
 619                 xfree(cp);
 620         }
 621         if (mux_command != 0 && options.control_path == NULL)
 622                 fatal("No ControlPath specified for \"-O\" command");
 623         if (options.control_path != NULL)
 624                 control_client(options.control_path);
 625
 626         /* Open a connection to the remote host. */
 627         if (ssh_connect(host, &hostaddr, options.port,
 628             options.address_family, options.connection_attempts,
 629 #ifdef HAVE_CYGWIN
 630             options.use_privileged_port,
 631 #else
 632             original_effective_uid == 0 && options.use_privileged_port,
 633 #endif
 634             options.proxy_command) != 0)
 635                 exit(1);
 636
 637         /*
 638          * If we successfully made the connection, load the host private key
 639          * in case we will need it later for combined rsa-rhosts
 640          * authentication. This must be done before releasing extra
 641          * privileges, because the file is only readable by root.
 642          * If we cannot access the private keys, load the public keys
 643          * instead and try to execute the ssh-keysign helper instead.
 644          */
 645         sensitive_data.nkeys = 0;
 646         sensitive_data.keys = NULL;
 647         sensitive_data.external_keysign = 0;
 648         if (options.rhosts_rsa_authentication ||
 649             options.hostbased_authentication) {
 650                 sensitive_data.nkeys = 3;
 651                 sensitive_data.keys = xmalloc(sensitive_data.nkeys *
 652                     sizeof(Key));
 653
 654                 PRIV_START;
 655                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
 656                     _PATH_HOST_KEY_FILE, "", NULL);
 657                 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
 658                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
 659                 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
 660                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
 661                 PRIV_END;
 662
 663                 if (options.hostbased_authentication == 1 &&
 664                     sensitive_data.keys[0] == NULL &&
 665                     sensitive_data.keys[1] == NULL &&
 666                     sensitive_data.keys[2] == NULL) {
 667                         sensitive_data.keys[1] = key_load_public(
 668                             _PATH_HOST_DSA_KEY_FILE, NULL);
 669                         sensitive_data.keys[2] = key_load_public(
 670                             _PATH_HOST_RSA_KEY_FILE, NULL);
 671                         sensitive_data.external_keysign = 1;
 672                 }
 673         }
 674         /*
 675          * Get rid of any extra privileges that we may have.  We will no
 676          * longer need them.  Also, extra privileges could make it very hard
 677          * to read identity files and other non-world-readable files from the
 678          * user's home directory if it happens to be on a NFS volume where
 679          * root is mapped to nobody.
 680          */
 681         if (original_effective_uid == 0) {
 682                 PRIV_START;
 683                 permanently_set_uid(pw);
 684         }
 685
 686         /*
 687          * Now that we are back to our own permissions, create ~/.ssh
 688          * directory if it doesn\'t already exist.
 689          */
 690         snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
 691         if (stat(buf, &st) < 0)
 692                 if (mkdir(buf, 0700) < 0)
 693                         error("Could not create directory '%.200s'.", buf);
 694
 695         /* load options.identity_files */
 696         load_public_identity_files();
 697
 698         /* Expand ~ in known host file names. */
 699         /* XXX mem-leaks: */
 700         options.system_hostfile =
 701             tilde_expand_filename(options.system_hostfile, original_real_uid);
 702         options.user_hostfile =
 703             tilde_expand_filename(options.user_hostfile, original_real_uid);
 704         options.system_hostfile2 =
 705             tilde_expand_filename(options.system_hostfile2, original_real_uid);
 706         options.user_hostfile2 =
 707             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 708
 709         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 710
 711         /* Log into the remote system.  This never returns if the login fails. */
 712         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw);
 713
 714         /* We no longer need the private host keys.  Clear them now. */
 715         if (sensitive_data.nkeys != 0) {
 716                 for (i = 0; i < sensitive_data.nkeys; i++) {
 717                         if (sensitive_data.keys[i] != NULL) {
 718                                 /* Destroys contents safely */
 719                                 debug3("clear hostkey %d", i);
 720                                 key_free(sensitive_data.keys[i]);
 721                                 sensitive_data.keys[i] = NULL;
 722                         }
 723                 }
 724                 xfree(sensitive_data.keys);
 725         }
 726         for (i = 0; i < options.num_identity_files; i++) {
 727                 if (options.identity_files[i]) {
 728                         xfree(options.identity_files[i]);
 729                         options.identity_files[i] = NULL;
 730                 }
 731                 if (options.identity_keys[i]) {
 732                         key_free(options.identity_keys[i]);
 733                         options.identity_keys[i] = NULL;
 734                 }
 735         }
 736
 737         exit_status = compat20 ? ssh_session2() : ssh_session();
 738         packet_close();
 739
 740         if (options.control_path != NULL && control_fd != -1)
 741                 unlink(options.control_path);
 742
 743         /*
 744          * Send SIGHUP to proxy command if used. We don't wait() in
 745          * case it hangs and instead rely on init to reap the child
 746          */
 747         if (proxy_command_pid > 1)
 748                 kill(proxy_command_pid, SIGHUP);
 749
 750         return exit_status;
 751 }
 752
 753 static void
 754 ssh_init_forwarding(void)
 755 {
 756         int success = 0;
 757         int i;
 758
 759         /* Initiate local TCP/IP port forwardings. */
 760         for (i = 0; i < options.num_local_forwards; i++) {
 761                 debug("Local connections to %.200s:%d forwarded to remote "
 762                     "address %.200s:%d",
 763                     (options.local_forwards[i].listen_host == NULL) ?
 764                     (options.gateway_ports ? "*" : "LOCALHOST") :
 765                     options.local_forwards[i].listen_host,
 766                     options.local_forwards[i].listen_port,
 767                     options.local_forwards[i].connect_host,
 768                     options.local_forwards[i].connect_port);
 769                 success += channel_setup_local_fwd_listener(
 770                     options.local_forwards[i].listen_host,
 771                     options.local_forwards[i].listen_port,
 772                     options.local_forwards[i].connect_host,
 773                     options.local_forwards[i].connect_port,
 774                     options.gateway_ports);
 775         }
 776         if (i > 0 && success == 0)
 777                 error("Could not request local forwarding.");
 778
 779         /* Initiate remote TCP/IP port forwardings. */
 780         for (i = 0; i < options.num_remote_forwards; i++) {
 781                 debug("Remote connections from %.200s:%d forwarded to "
 782                     "local address %.200s:%d",
 783                     (options.remote_forwards[i].listen_host == NULL) ?
 784                     (options.gateway_ports ? "*" : "LOCALHOST") :
 785                     options.remote_forwards[i].listen_host,
 786                     options.remote_forwards[i].listen_port,
 787                     options.remote_forwards[i].connect_host,
 788                     options.remote_forwards[i].connect_port);
 789                 channel_request_remote_forwarding(
 790                     options.remote_forwards[i].listen_host,
 791                     options.remote_forwards[i].listen_port,
 792                     options.remote_forwards[i].connect_host,
 793                     options.remote_forwards[i].connect_port);
 794         }
 795 }
 796
 797 static void
 798 check_agent_present(void)
 799 {
 800         if (options.forward_agent) {
 801                 /* Clear agent forwarding if we don\'t have an agent. */
 802                 if (!ssh_agent_present())
 803                         options.forward_agent = 0;
 804         }
 805 }
 806
 807 static int
 808 ssh_session(void)
 809 {
 810         int type;
 811         int interactive = 0;
 812         int have_tty = 0;
 813         struct winsize ws;
 814         char *cp;
 815         const char *display;
 816
 817         /* Enable compression if requested. */
 818         if (options.compression) {
 819                 debug("Requesting compression at level %d.", options.compression_level);
 820
 821                 if (options.compression_level < 1 || options.compression_level > 9)
 822                         fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
 823
 824                 /* Send the request. */
 825                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
 826                 packet_put_int(options.compression_level);
 827                 packet_send();
 828                 packet_write_wait();
 829                 type = packet_read();
 830                 if (type == SSH_SMSG_SUCCESS)
 831                         packet_start_compression(options.compression_level);
 832                 else if (type == SSH_SMSG_FAILURE)
 833                         logit("Warning: Remote host refused compression.");
 834                 else
 835                         packet_disconnect("Protocol error waiting for compression response.");
 836         }
 837         /* Allocate a pseudo tty if appropriate. */
 838         if (tty_flag) {
 839                 debug("Requesting pty.");
 840
 841                 /* Start the packet. */
 842                 packet_start(SSH_CMSG_REQUEST_PTY);
 843
 844                 /* Store TERM in the packet.  There is no limit on the
 845                    length of the string. */
 846                 cp = getenv("TERM");
 847                 if (!cp)
 848                         cp = "";
 849                 packet_put_cstring(cp);
 850
 851                 /* Store window size in the packet. */
 852                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
 853                         memset(&ws, 0, sizeof(ws));
 854                 packet_put_int(ws.ws_row);
 855                 packet_put_int(ws.ws_col);
 856                 packet_put_int(ws.ws_xpixel);
 857                 packet_put_int(ws.ws_ypixel);
 858
 859                 /* Store tty modes in the packet. */
 860                 tty_make_modes(fileno(stdin), NULL);
 861
 862                 /* Send the packet, and wait for it to leave. */
 863                 packet_send();
 864                 packet_write_wait();
 865
 866                 /* Read response from the server. */
 867                 type = packet_read();
 868                 if (type == SSH_SMSG_SUCCESS) {
 869                         interactive = 1;
 870                         have_tty = 1;
 871                 } else if (type == SSH_SMSG_FAILURE)
 872                         logit("Warning: Remote host failed or refused to allocate a pseudo tty.");
 873                 else
 874                         packet_disconnect("Protocol error waiting for pty request response.");
 875         }
 876         /* Request X11 forwarding if enabled and DISPLAY is set. */
 877         display = getenv("DISPLAY");
 878         if (options.forward_x11 && display != NULL) {
 879                 char *proto, *data;
 880                 /* Get reasonable local authentication information. */
 881                 client_x11_get_proto(display, options.xauth_location,
 882                     options.forward_x11_trusted, &proto, &data);
 883                 /* Request forwarding with authentication spoofing. */
 884                 debug("Requesting X11 forwarding with authentication spoofing.");
 885                 x11_request_forwarding_with_spoofing(0, display, proto, data);
 886
 887                 /* Read response from the server. */
 888                 type = packet_read();
 889                 if (type == SSH_SMSG_SUCCESS) {
 890                         interactive = 1;
 891                 } else if (type == SSH_SMSG_FAILURE) {
 892                         logit("Warning: Remote host denied X11 forwarding.");
 893                 } else {
 894                         packet_disconnect("Protocol error waiting for X11 forwarding");
 895                 }
 896         }
 897         /* Tell the packet module whether this is an interactive session. */
 898         packet_set_interactive(interactive);
 899
 900         /* Request authentication agent forwarding if appropriate. */
 901         check_agent_present();
 902
 903         if (options.forward_agent) {
 904                 debug("Requesting authentication agent forwarding.");
 905                 auth_request_forwarding();
 906
 907                 /* Read response from the server. */
 908                 type = packet_read();
 909                 packet_check_eom();
 910                 if (type != SSH_SMSG_SUCCESS)
 911                         logit("Warning: Remote host denied authentication agent forwarding.");
 912         }
 913
 914         /* Initiate port forwardings. */
 915         ssh_init_forwarding();
 916
 917         /* If requested, let ssh continue in the background. */
 918         if (fork_after_authentication_flag)
 919                 if (daemon(1, 1) < 0)
 920                         fatal("daemon() failed: %.200s", strerror(errno));
 921
 922         /*
 923          * If a command was specified on the command line, execute the
 924          * command now. Otherwise request the server to start a shell.
 925          */
 926         if (buffer_len(&command) > 0) {
 927                 int len = buffer_len(&command);
 928                 if (len > 900)
 929                         len = 900;
 930                 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
 931                 packet_start(SSH_CMSG_EXEC_CMD);
 932                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
 933                 packet_send();
 934                 packet_write_wait();
 935         } else {
 936                 debug("Requesting shell.");
 937                 packet_start(SSH_CMSG_EXEC_SHELL);
 938                 packet_send();
 939                 packet_write_wait();
 940         }
 941
 942         /* Enter the interactive session. */
 943         return client_loop(have_tty, tty_flag ?
 944             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
 945 }
 946
 947 static void
 948 ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt)
 949 {
 950         int id, len;
 951
 952         id = packet_get_int();
 953         len = buffer_len(&command);
 954         if (len > 900)
 955                 len = 900;
 956         packet_check_eom();
 957         if (type == SSH2_MSG_CHANNEL_FAILURE)
 958                 fatal("Request for subsystem '%.*s' failed on channel %d",
 959                     len, (u_char *)buffer_ptr(&command), id);
 960 }
 961
 962 void
 963 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
 964 {
 965         int i;
 966
 967         i = client_global_request_id++;
 968         if (i >= options.num_remote_forwards)
 969                 return;
 970         debug("remote forward %s for: listen %d, connect %s:%d",
 971             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
 972             options.remote_forwards[i].listen_port,
 973             options.remote_forwards[i].connect_host,
 974             options.remote_forwards[i].connect_port);
 975         if (type == SSH2_MSG_REQUEST_FAILURE)
 976                 logit("Warning: remote port forwarding failed for listen "
 977                     "port %d", options.remote_forwards[i].listen_port);
 978 }
 979
 980 static void
 981 ssh_control_listener(void)
 982 {
 983         struct sockaddr_un addr;
 984         mode_t old_umask;
 985         int addr_len;
 986
 987         if (options.control_path == NULL ||
 988             options.control_master == SSHCTL_MASTER_NO)
 989                 return;
 990
 991         debug("setting up multiplex master socket");
 992
 993         memset(&addr, '\0', sizeof(addr));
 994         addr.sun_family = AF_UNIX;
 995         addr_len = offsetof(struct sockaddr_un, sun_path) +
 996             strlen(options.control_path) + 1;
 997
 998         if (strlcpy(addr.sun_path, options.control_path,
 999             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1000                 fatal("ControlPath too long");
1001
1002         if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1003                 fatal("%s socket(): %s\n", __func__, strerror(errno));
1004
1005         old_umask = umask(0177);
1006         if (bind(control_fd, (struct sockaddr*)&addr, addr_len) == -1) {
1007                 control_fd = -1;
1008                 if (errno == EINVAL || errno == EADDRINUSE)
1009                         fatal("ControlSocket %s already exists",
1010                             options.control_path);
1011                 else
1012                         fatal("%s bind(): %s\n", __func__, strerror(errno));
1013         }
1014         umask(old_umask);
1015
1016         if (listen(control_fd, 64) == -1)
1017                 fatal("%s listen(): %s\n", __func__, strerror(errno));
1018
1019         set_nonblock(control_fd);
1020 }
1021
1022 /* request pty/x11/agent/tcpfwd/shell for channel */
1023 static void
1024 ssh_session2_setup(int id, void *arg)
1025 {
1026         extern char **environ;
1027         const char *display;
1028         int interactive = tty_flag;
1029
1030         display = getenv("DISPLAY");
1031         if (options.forward_x11 && display != NULL) {
1032                 char *proto, *data;
1033                 /* Get reasonable local authentication information. */
1034                 client_x11_get_proto(display, options.xauth_location,
1035                     options.forward_x11_trusted, &proto, &data);
1036                 /* Request forwarding with authentication spoofing. */
1037                 debug("Requesting X11 forwarding with authentication spoofing.");
1038                 x11_request_forwarding_with_spoofing(id, display, proto, data);
1039                 interactive = 1;
1040                 /* XXX wait for reply */
1041         }
1042
1043         check_agent_present();
1044         if (options.forward_agent) {
1045                 debug("Requesting authentication agent forwarding.");
1046                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1047                 packet_send();
1048         }
1049
1050         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1051             NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply);
1052
1053         packet_set_interactive(interactive);
1054 }
1055
1056 /* open new channel for a session */
1057 static int
1058 ssh_session2_open(void)
1059 {
1060         Channel *c;
1061         int window, packetmax, in, out, err;
1062
1063         if (stdin_null_flag) {
1064                 in = open(_PATH_DEVNULL, O_RDONLY);
1065         } else {
1066                 in = dup(STDIN_FILENO);
1067         }
1068         out = dup(STDOUT_FILENO);
1069         err = dup(STDERR_FILENO);
1070
1071         if (in < 0 || out < 0 || err < 0)
1072                 fatal("dup() in/out/err failed");
1073
1074         /* enable nonblocking unless tty */
1075         if (!isatty(in))
1076                 set_nonblock(in);
1077         if (!isatty(out))
1078                 set_nonblock(out);
1079         if (!isatty(err))
1080                 set_nonblock(err);
1081
1082         window = CHAN_SES_WINDOW_DEFAULT;
1083         packetmax = CHAN_SES_PACKET_DEFAULT;
1084         if (tty_flag) {
1085                 window >>= 1;
1086                 packetmax >>= 1;
1087         }
1088         c = channel_new(
1089             "session", SSH_CHANNEL_OPENING, in, out, err,
1090             window, packetmax, CHAN_EXTENDED_WRITE,
1091             "client-session", /*nonblock*/0);
1092
1093         debug3("ssh_session2_open: channel_new: %d", c->self);
1094
1095         channel_send_open(c->self);
1096         if (!no_shell_flag)
1097                 channel_register_confirm(c->self, ssh_session2_setup, NULL);
1098
1099         return c->self;
1100 }
1101
1102 static int
1103 ssh_session2(void)
1104 {
1105         int id = -1;
1106
1107         /* XXX should be pre-session */
1108         ssh_init_forwarding();
1109         ssh_control_listener();
1110
1111         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1112                 id = ssh_session2_open();
1113
1114         /* If requested, let ssh continue in the background. */
1115         if (fork_after_authentication_flag)
1116                 if (daemon(1, 1) < 0)
1117                         fatal("daemon() failed: %.200s", strerror(errno));
1118
1119         return client_loop(tty_flag, tty_flag ?
1120             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1121 }
1122
1123 static void
1124 load_public_identity_files(void)
1125 {
1126         char *filename;
1127         int i = 0;
1128         Key *public;
1129 #ifdef SMARTCARD
1130         Key **keys;
1131
1132         if (options.smartcard_device != NULL &&
1133             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1134             (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL ) {
1135                 int count = 0;
1136                 for (i = 0; keys[i] != NULL; i++) {
1137                         count++;
1138                         memmove(&options.identity_files[1], &options.identity_files[0],
1139                             sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1140                         memmove(&options.identity_keys[1], &options.identity_keys[0],
1141                             sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1142                         options.num_identity_files++;
1143                         options.identity_keys[0] = keys[i];
1144                         options.identity_files[0] = sc_get_key_label(keys[i]);
1145                 }
1146                 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1147                         options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1148                 i = count;
1149                 xfree(keys);
1150         }
1151 #endif /* SMARTCARD */
1152         for (; i < options.num_identity_files; i++) {
1153                 filename = tilde_expand_filename(options.identity_files[i],
1154                     original_real_uid);
1155                 public = key_load_public(filename, NULL);
1156                 debug("identity file %s type %d", filename,
1157                     public ? public->type : -1);
1158                 xfree(options.identity_files[i]);
1159                 options.identity_files[i] = filename;
1160                 options.identity_keys[i] = public;
1161         }
1162 }
1163
1164 static void
1165 control_client_sighandler(int signo)
1166 {
1167         control_client_terminate = signo;
1168 }
1169
1170 static void
1171 control_client_sigrelay(int signo)
1172 {
1173         if (control_server_pid > 1)
1174                 kill(control_server_pid, signo);
1175 }
1176
1177 static int
1178 env_permitted(char *env)
1179 {
1180         int i;
1181         char name[1024], *cp;
1182
1183         strlcpy(name, env, sizeof(name));
1184         if ((cp = strchr(name, '=')) == NULL)
1185                 return (0);
1186
1187         *cp = '\0';
1188
1189         for (i = 0; i < options.num_send_env; i++)
1190                 if (match_pattern(name, options.send_env[i]))
1191                         return (1);
1192
1193         return (0);
1194 }
1195
1196 static void
1197 control_client(const char *path)
1198 {
1199         struct sockaddr_un addr;
1200         int i, r, fd, sock, exitval, num_env, addr_len;
1201         Buffer m;
1202         char *term;
1203         extern char **environ;
1204         u_int  flags;
1205
1206         if (mux_command == 0)
1207                 mux_command = SSHMUX_COMMAND_OPEN;
1208
1209         switch (options.control_master) {
1210         case SSHCTL_MASTER_AUTO:
1211         case SSHCTL_MASTER_AUTO_ASK:
1212                 debug("auto-mux: Trying existing master");
1213                 /* FALLTHROUGH */
1214         case SSHCTL_MASTER_NO:
1215                 break;
1216         default:
1217                 return;
1218         }
1219
1220         memset(&addr, '\0', sizeof(addr));
1221         addr.sun_family = AF_UNIX;
1222         addr_len = offsetof(struct sockaddr_un, sun_path) +
1223             strlen(path) + 1;
1224
1225         if (strlcpy(addr.sun_path, path,
1226             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1227                 fatal("ControlPath too long");
1228
1229         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1230                 fatal("%s socket(): %s", __func__, strerror(errno));
1231
1232         if (connect(sock, (struct sockaddr*)&addr, addr_len) == -1) {
1233                 if (mux_command != SSHMUX_COMMAND_OPEN) {
1234                         fatal("Control socket connect(%.100s): %s", path,
1235                             strerror(errno));
1236                 }
1237                 if (errno == ENOENT)
1238                         debug("Control socket \"%.100s\" does not exist", path);
1239                 else {
1240                         error("Control socket connect(%.100s): %s", path,
1241                             strerror(errno));
1242                 }
1243                 close(sock);
1244                 return;
1245         }
1246
1247         if (stdin_null_flag) {
1248                 if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1249                         fatal("open(/dev/null): %s", strerror(errno));
1250                 if (dup2(fd, STDIN_FILENO) == -1)
1251                         fatal("dup2: %s", strerror(errno));
1252                 if (fd > STDERR_FILENO)
1253                         close(fd);
1254         }
1255
1256         if ((term = getenv("TERM")) == NULL)
1257                 term = "";
1258
1259         flags = 0;
1260         if (tty_flag)
1261                 flags |= SSHMUX_FLAG_TTY;
1262         if (subsystem_flag)
1263                 flags |= SSHMUX_FLAG_SUBSYS;
1264
1265         buffer_init(&m);
1266
1267         /* Send our command to server */
1268         buffer_put_int(&m, mux_command);
1269         buffer_put_int(&m, flags);
1270         if (ssh_msg_send(sock, /* version */1, &m) == -1)
1271                 fatal("%s: msg_send", __func__);
1272         buffer_clear(&m);
1273
1274         /* Get authorisation status and PID of controlee */
1275         if (ssh_msg_recv(sock, &m) == -1)
1276                 fatal("%s: msg_recv", __func__);
1277         if (buffer_get_char(&m) != 1)
1278                 fatal("%s: wrong version", __func__);
1279         if (buffer_get_int(&m) != 1)
1280                 fatal("Connection to master denied");
1281         control_server_pid = buffer_get_int(&m);
1282
1283         buffer_clear(&m);
1284
1285         switch (mux_command) {
1286         case SSHMUX_COMMAND_ALIVE_CHECK:
1287                 fprintf(stderr, "Master running (pid=%d)\r\n",
1288                     control_server_pid);
1289                 exit(0);
1290         case SSHMUX_COMMAND_TERMINATE:
1291                 fprintf(stderr, "Exit request sent.\r\n");
1292                 exit(0);
1293         case SSHMUX_COMMAND_OPEN:
1294                 /* continue below */
1295                 break;
1296         default:
1297                 fatal("silly mux_command %d", mux_command);
1298         }
1299
1300         /* SSHMUX_COMMAND_OPEN */
1301         buffer_put_cstring(&m, term);
1302         buffer_append(&command, "\0", 1);
1303         buffer_put_cstring(&m, buffer_ptr(&command));
1304
1305         if (options.num_send_env == 0 || environ == NULL) {
1306                 buffer_put_int(&m, 0);
1307         } else {
1308                 /* Pass environment */
1309                 num_env = 0;
1310                 for (i = 0; environ[i] != NULL; i++)
1311                         if (env_permitted(environ[i]))
1312                                 num_env++; /* Count */
1313
1314                 buffer_put_int(&m, num_env);
1315
1316                 for (i = 0; environ[i] != NULL && num_env >= 0; i++)
1317                         if (env_permitted(environ[i])) {
1318                                 num_env--;
1319                                 buffer_put_cstring(&m, environ[i]);
1320                         }
1321         }
1322
1323         if (ssh_msg_send(sock, /* version */1, &m) == -1)
1324                 fatal("%s: msg_send", __func__);
1325
1326         mm_send_fd(sock, STDIN_FILENO);
1327         mm_send_fd(sock, STDOUT_FILENO);
1328         mm_send_fd(sock, STDERR_FILENO);
1329
1330         /* Wait for reply, so master has a chance to gather ttymodes */
1331         buffer_clear(&m);
1332         if (ssh_msg_recv(sock, &m) == -1)
1333                 fatal("%s: msg_recv", __func__);
1334         if (buffer_get_char(&m) != 1)
1335                 fatal("%s: wrong version", __func__);
1336         buffer_free(&m);
1337
1338         signal(SIGHUP, control_client_sighandler);
1339         signal(SIGINT, control_client_sighandler);
1340         signal(SIGTERM, control_client_sighandler);
1341         signal(SIGWINCH, control_client_sigrelay);
1342
1343         if (tty_flag)
1344                 enter_raw_mode();
1345
1346         /* Stick around until the controlee closes the client_fd */
1347         exitval = 0;
1348         for (;!control_client_terminate;) {
1349                 r = read(sock, &exitval, sizeof(exitval));
1350                 if (r == 0) {
1351                         debug2("Received EOF from master");
1352                         break;
1353                 }
1354                 if (r > 0)
1355                         debug2("Received exit status from master %d", exitval);
1356                 if (r == -1 && errno != EINTR)
1357                         fatal("%s: read %s", __func__, strerror(errno));
1358         }
1359
1360         if (control_client_terminate)
1361                 debug2("Exiting on signal %d", control_client_terminate);
1362
1363         close(sock);
1364
1365         leave_raw_mode();
1366
1367         if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1368                 fprintf(stderr, "Connection to master closed.\r\n");
1369
1370         exit(exitval);
1371 }