ssh.c

   1 /* $OpenBSD: ssh.c,v 1.279 2006/07/06 16:03:53 stevesk Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Ssh client program.  This program can be used to log into a remote machine.
   7  * The software supports strong authentication, encryption, and forwarding
   8  * of X11, TCP/IP, and authentication connections.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  18  *
  19  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
  20  * in Canada (German citizen).
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  * 1. Redistributions of source code must retain the above copyright
  26  *    notice, this list of conditions and the following disclaimer.
  27  * 2. Redistributions in binary form must reproduce the above copyright
  28  *    notice, this list of conditions and the following disclaimer in the
  29  *    documentation and/or other materials provided with the distribution.
  30  *
  31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  32  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  33  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  34  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  41  */
  42
  43 #include "includes.h"
  44
  45 #include <sys/types.h>
  46 #ifdef HAVE_SYS_STAT_H
  47 # include <sys/stat.h>
  48 #endif
  49 #include <sys/resource.h>
  50 #include <sys/ioctl.h>
  51 #include <sys/un.h>
  52
  53 #include <ctype.h>
  54 #ifdef HAVE_PATHS_H
  55 #include <paths.h>
  56 #endif
  57 #include <pwd.h>
  58 #include <signal.h>
  59
  60 #include <openssl/evp.h>
  61 #include <openssl/err.h>
  62
  63 #include "ssh.h"
  64 #include "ssh1.h"
  65 #include "ssh2.h"
  66 #include "compat.h"
  67 #include "cipher.h"
  68 #include "xmalloc.h"
  69 #include "packet.h"
  70 #include "buffer.h"
  71 #include "bufaux.h"
  72 #include "channels.h"
  73 #include "key.h"
  74 #include "authfd.h"
  75 #include "authfile.h"
  76 #include "pathnames.h"
  77 #include "dispatch.h"
  78 #include "clientloop.h"
  79 #include "log.h"
  80 #include "readconf.h"
  81 #include "sshconnect.h"
  82 #include "misc.h"
  83 #include "kex.h"
  84 #include "mac.h"
  85 #include "sshpty.h"
  86 #include "match.h"
  87 #include "msg.h"
  88 #include "monitor_fdpass.h"
  89 #include "uidswap.h"
  90 #include "version.h"
  91
  92 #ifdef SMARTCARD
  93 #include "scard.h"
  94 #endif
  95
  96 extern char *__progname;
  97
  98 /* Flag indicating whether debug mode is on.  This can be set on the command line. */
  99 int debug_flag = 0;
 100
 101 /* Flag indicating whether a tty should be allocated */
 102 int tty_flag = 0;
 103 int no_tty_flag = 0;
 104 int force_tty_flag = 0;
 105
 106 /* don't exec a shell */
 107 int no_shell_flag = 0;
 108
 109 /*
 110  * Flag indicating that nothing should be read from stdin.  This can be set
 111  * on the command line.
 112  */
 113 int stdin_null_flag = 0;
 114
 115 /*
 116  * Flag indicating that ssh should fork after authentication.  This is useful
 117  * so that the passphrase can be entered manually, and then ssh goes to the
 118  * background.
 119  */
 120 int fork_after_authentication_flag = 0;
 121
 122 /*
 123  * General data structure for command line options and options configurable
 124  * in configuration files.  See readconf.h.
 125  */
 126 Options options;
 127
 128 /* optional user configfile */
 129 char *config = NULL;
 130
 131 /*
 132  * Name of the host we are connecting to.  This is the name given on the
 133  * command line, or the HostName specified for the user-supplied name in a
 134  * configuration file.
 135  */
 136 char *host;
 137
 138 /* socket address the host resolves to */
 139 struct sockaddr_storage hostaddr;
 140
 141 /* Private host keys. */
 142 Sensitive sensitive_data;
 143
 144 /* Original real UID. */
 145 uid_t original_real_uid;
 146 uid_t original_effective_uid;
 147
 148 /* command to be executed */
 149 Buffer command;
 150
 151 /* Should we execute a command or invoke a subsystem? */
 152 int subsystem_flag = 0;
 153
 154 /* # of replies received for global requests */
 155 static int client_global_request_id = 0;
 156
 157 /* pid of proxycommand child process */
 158 pid_t proxy_command_pid = 0;
 159
 160 /* fd to control socket */
 161 int control_fd = -1;
 162
 163 /* Multiplexing control command */
 164 static u_int mux_command = 0;
 165
 166 /* Only used in control client mode */
 167 volatile sig_atomic_t control_client_terminate = 0;
 168 u_int control_server_pid = 0;
 169
 170 /* Prints a help message to the user.  This function never returns. */
 171
 172 static void
 173 usage(void)
 174 {
 175         fprintf(stderr,
 176 "usage: ssh [-1246AaCfgkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
 177 "           [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
 178 "           [-i identity_file] [-L [bind_address:]port:host:hostport]\n"
 179 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 180 "           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
 181 "           [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
 182         );
 183         exit(255);
 184 }
 185
 186 static int ssh_session(void);
 187 static int ssh_session2(void);
 188 static void load_public_identity_files(void);
 189 static void control_client(const char *path);
 190
 191 /*
 192  * Main program for the ssh client.
 193  */
 194 int
 195 main(int ac, char **av)
 196 {
 197         int i, opt, exit_status;
 198         char *p, *cp, *line, buf[256];
 199         struct stat st;
 200         struct passwd *pw;
 201         int dummy;
 202         extern int optind, optreset;
 203         extern char *optarg;
 204         struct servent *sp;
 205         Forward fwd;
 206
 207         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 208         sanitise_stdfd();
 209
 210         __progname = ssh_get_progname(av[0]);
 211         init_rng();
 212
 213         /*
 214          * Save the original real uid.  It will be needed later (uid-swapping
 215          * may clobber the real uid).
 216          */
 217         original_real_uid = getuid();
 218         original_effective_uid = geteuid();
 219
 220         /*
 221          * Use uid-swapping to give up root privileges for the duration of
 222          * option processing.  We will re-instantiate the rights when we are
 223          * ready to create the privileged port, and will permanently drop
 224          * them when the port has been created (actually, when the connection
 225          * has been made, as we may need to create the port several times).
 226          */
 227         PRIV_END;
 228
 229 #ifdef HAVE_SETRLIMIT
 230         /* If we are installed setuid root be careful to not drop core. */
 231         if (original_real_uid != original_effective_uid) {
 232                 struct rlimit rlim;
 233                 rlim.rlim_cur = rlim.rlim_max = 0;
 234                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 235                         fatal("setrlimit failed: %.100s", strerror(errno));
 236         }
 237 #endif
 238         /* Get user data. */
 239         pw = getpwuid(original_real_uid);
 240         if (!pw) {
 241                 logit("You don't exist, go away!");
 242                 exit(255);
 243         }
 244         /* Take a copy of the returned structure. */
 245         pw = pwcopy(pw);
 246
 247         /*
 248          * Set our umask to something reasonable, as some files are created
 249          * with the default umask.  This will make them world-readable but
 250          * writable only by the owner, which is ok for all files for which we
 251          * don't set the modes explicitly.
 252          */
 253         umask(022);
 254
 255         /* Initialize option structure to indicate that no values have been set. */
 256         initialize_options(&options);
 257
 258         /* Parse command-line arguments. */
 259         host = NULL;
 260
 261  again:
 262         while ((opt = getopt(ac, av,
 263             "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNO:PR:S:TVw:XY")) != -1) {
 264                 switch (opt) {
 265                 case '1':
 266                         options.protocol = SSH_PROTO_1;
 267                         break;
 268                 case '2':
 269                         options.protocol = SSH_PROTO_2;
 270                         break;
 271                 case '4':
 272                         options.address_family = AF_INET;
 273                         break;
 274                 case '6':
 275                         options.address_family = AF_INET6;
 276                         break;
 277                 case 'n':
 278                         stdin_null_flag = 1;
 279                         break;
 280                 case 'f':
 281                         fork_after_authentication_flag = 1;
 282                         stdin_null_flag = 1;
 283                         break;
 284                 case 'x':
 285                         options.forward_x11 = 0;
 286                         break;
 287                 case 'X':
 288                         options.forward_x11 = 1;
 289                         break;
 290                 case 'Y':
 291                         options.forward_x11 = 1;
 292                         options.forward_x11_trusted = 1;
 293                         break;
 294                 case 'g':
 295                         options.gateway_ports = 1;
 296                         break;
 297                 case 'O':
 298                         if (strcmp(optarg, "check") == 0)
 299                                 mux_command = SSHMUX_COMMAND_ALIVE_CHECK;
 300                         else if (strcmp(optarg, "exit") == 0)
 301                                 mux_command = SSHMUX_COMMAND_TERMINATE;
 302                         else
 303                                 fatal("Invalid multiplex command.");
 304                         break;
 305                 case 'P':       /* deprecated */
 306                         options.use_privileged_port = 0;
 307                         break;
 308                 case 'a':
 309                         options.forward_agent = 0;
 310                         break;
 311                 case 'A':
 312                         options.forward_agent = 1;
 313                         break;
 314                 case 'k':
 315                         options.gss_deleg_creds = 0;
 316                         break;
 317                 case 'i':
 318                         if (stat(optarg, &st) < 0) {
 319                                 fprintf(stderr, "Warning: Identity file %s "
 320                                     "not accessible: %s.\n", optarg,
 321                                     strerror(errno));
 322                                 break;
 323                         }
 324                         if (options.num_identity_files >=
 325                             SSH_MAX_IDENTITY_FILES)
 326                                 fatal("Too many identity files specified "
 327                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
 328                         options.identity_files[options.num_identity_files++] =
 329                             xstrdup(optarg);
 330                         break;
 331                 case 'I':
 332 #ifdef SMARTCARD
 333                         options.smartcard_device = xstrdup(optarg);
 334 #else
 335                         fprintf(stderr, "no support for smartcards.\n");
 336 #endif
 337                         break;
 338                 case 't':
 339                         if (tty_flag)
 340                                 force_tty_flag = 1;
 341                         tty_flag = 1;
 342                         break;
 343                 case 'v':
 344                         if (debug_flag == 0) {
 345                                 debug_flag = 1;
 346                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 347                         } else {
 348                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 349                                         options.log_level++;
 350                                 break;
 351                         }
 352                         /* FALLTHROUGH */
 353                 case 'V':
 354                         fprintf(stderr, "%s, %s\n",
 355                             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
 356                         if (opt == 'V')
 357                                 exit(0);
 358                         break;
 359                 case 'w':
 360                         if (options.tun_open == -1)
 361                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 362                         options.tun_local = a2tun(optarg, &options.tun_remote);
 363                         if (options.tun_local == SSH_TUNID_ERR) {
 364                                 fprintf(stderr, "Bad tun device '%s'\n", optarg);
 365                                 exit(255);
 366                         }
 367                         break;
 368                 case 'q':
 369                         options.log_level = SYSLOG_LEVEL_QUIET;
 370                         break;
 371                 case 'e':
 372                         if (optarg[0] == '^' && optarg[2] == 0 &&
 373                             (u_char) optarg[1] >= 64 &&
 374                             (u_char) optarg[1] < 128)
 375                                 options.escape_char = (u_char) optarg[1] & 31;
 376                         else if (strlen(optarg) == 1)
 377                                 options.escape_char = (u_char) optarg[0];
 378                         else if (strcmp(optarg, "none") == 0)
 379                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 380                         else {
 381                                 fprintf(stderr, "Bad escape character '%s'.\n",
 382                                     optarg);
 383                                 exit(255);
 384                         }
 385                         break;
 386                 case 'c':
 387                         if (ciphers_valid(optarg)) {
 388                                 /* SSH2 only */
 389                                 options.ciphers = xstrdup(optarg);
 390                                 options.cipher = SSH_CIPHER_INVALID;
 391                         } else {
 392                                 /* SSH1 only */
 393                                 options.cipher = cipher_number(optarg);
 394                                 if (options.cipher == -1) {
 395                                         fprintf(stderr,
 396                                             "Unknown cipher type '%s'\n",
 397                                             optarg);
 398                                         exit(255);
 399                                 }
 400                                 if (options.cipher == SSH_CIPHER_3DES)
 401                                         options.ciphers = "3des-cbc";
 402                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 403                                         options.ciphers = "blowfish-cbc";
 404                                 else
 405                                         options.ciphers = (char *)-1;
 406                         }
 407                         break;
 408                 case 'm':
 409                         if (mac_valid(optarg))
 410                                 options.macs = xstrdup(optarg);
 411                         else {
 412                                 fprintf(stderr, "Unknown mac type '%s'\n",
 413                                     optarg);
 414                                 exit(255);
 415                         }
 416                         break;
 417                 case 'M':
 418                         if (options.control_master == SSHCTL_MASTER_YES)
 419                                 options.control_master = SSHCTL_MASTER_ASK;
 420                         else
 421                                 options.control_master = SSHCTL_MASTER_YES;
 422                         break;
 423                 case 'p':
 424                         options.port = a2port(optarg);
 425                         if (options.port == 0) {
 426                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 427                                 exit(255);
 428                         }
 429                         break;
 430                 case 'l':
 431                         options.user = optarg;
 432                         break;
 433
 434                 case 'L':
 435                         if (parse_forward(&fwd, optarg))
 436                                 add_local_forward(&options, &fwd);
 437                         else {
 438                                 fprintf(stderr,
 439                                     "Bad local forwarding specification '%s'\n",
 440                                     optarg);
 441                                 exit(255);
 442                         }
 443                         break;
 444
 445                 case 'R':
 446                         if (parse_forward(&fwd, optarg)) {
 447                                 add_remote_forward(&options, &fwd);
 448                         } else {
 449                                 fprintf(stderr,
 450                                     "Bad remote forwarding specification "
 451                                     "'%s'\n", optarg);
 452                                 exit(255);
 453                         }
 454                         break;
 455
 456                 case 'D':
 457                         cp = p = xstrdup(optarg);
 458                         memset(&fwd, '\0', sizeof(fwd));
 459                         fwd.connect_host = "socks";
 460                         if ((fwd.listen_host = hpdelim(&cp)) == NULL) {
 461                                 fprintf(stderr, "Bad dynamic forwarding "
 462                                     "specification '%.100s'\n", optarg);
 463                                 exit(255);
 464                         }
 465                         if (cp != NULL) {
 466                                 fwd.listen_port = a2port(cp);
 467                                 fwd.listen_host = cleanhostname(fwd.listen_host);
 468                         } else {
 469                                 fwd.listen_port = a2port(fwd.listen_host);
 470                                 fwd.listen_host = NULL;
 471                         }
 472
 473                         if (fwd.listen_port == 0) {
 474                                 fprintf(stderr, "Bad dynamic port '%s'\n",
 475                                     optarg);
 476                                 exit(255);
 477                         }
 478                         add_local_forward(&options, &fwd);
 479                         xfree(p);
 480                         break;
 481
 482                 case 'C':
 483                         options.compression = 1;
 484                         break;
 485                 case 'N':
 486                         no_shell_flag = 1;
 487                         no_tty_flag = 1;
 488                         break;
 489                 case 'T':
 490                         no_tty_flag = 1;
 491                         break;
 492                 case 'o':
 493                         dummy = 1;
 494                         line = xstrdup(optarg);
 495                         if (process_config_line(&options, host ? host : "",
 496                             line, "command-line", 0, &dummy) != 0)
 497                                 exit(255);
 498                         xfree(line);
 499                         break;
 500                 case 's':
 501                         subsystem_flag = 1;
 502                         break;
 503                 case 'S':
 504                         if (options.control_path != NULL)
 505                                 free(options.control_path);
 506                         options.control_path = xstrdup(optarg);
 507                         break;
 508                 case 'b':
 509                         options.bind_address = optarg;
 510                         break;
 511                 case 'F':
 512                         config = optarg;
 513                         break;
 514                 default:
 515                         usage();
 516                 }
 517         }
 518
 519         ac -= optind;
 520         av += optind;
 521
 522         if (ac > 0 && !host && **av != '-') {
 523                 if (strrchr(*av, '@')) {
 524                         p = xstrdup(*av);
 525                         cp = strrchr(p, '@');
 526                         if (cp == NULL || cp == p)
 527                                 usage();
 528                         options.user = p;
 529                         *cp = '\0';
 530                         host = ++cp;
 531                 } else
 532                         host = *av;
 533                 if (ac > 1) {
 534                         optind = optreset = 1;
 535                         goto again;
 536                 }
 537                 ac--, av++;
 538         }
 539
 540         /* Check that we got a host name. */
 541         if (!host)
 542                 usage();
 543
 544         SSLeay_add_all_algorithms();
 545         ERR_load_crypto_strings();
 546
 547         /* Initialize the command to execute on remote host. */
 548         buffer_init(&command);
 549
 550         /*
 551          * Save the command to execute on the remote host in a buffer. There
 552          * is no limit on the length of the command, except by the maximum
 553          * packet size.  Also sets the tty flag if there is no command.
 554          */
 555         if (!ac) {
 556                 /* No command specified - execute shell on a tty. */
 557                 tty_flag = 1;
 558                 if (subsystem_flag) {
 559                         fprintf(stderr,
 560                             "You must specify a subsystem to invoke.\n");
 561                         usage();
 562                 }
 563         } else {
 564                 /* A command has been specified.  Store it into the buffer. */
 565                 for (i = 0; i < ac; i++) {
 566                         if (i)
 567                                 buffer_append(&command, " ", 1);
 568                         buffer_append(&command, av[i], strlen(av[i]));
 569                 }
 570         }
 571
 572         /* Cannot fork to background if no command. */
 573         if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
 574                 fatal("Cannot fork into background without a command to execute.");
 575
 576         /* Allocate a tty by default if no command specified. */
 577         if (buffer_len(&command) == 0)
 578                 tty_flag = 1;
 579
 580         /* Force no tty */
 581         if (no_tty_flag)
 582                 tty_flag = 0;
 583         /* Do not allocate a tty if stdin is not a tty. */
 584         if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
 585                 if (tty_flag)
 586                         logit("Pseudo-terminal will not be allocated because stdin is not a terminal.");
 587                 tty_flag = 0;
 588         }
 589
 590         /*
 591          * Initialize "log" output.  Since we are the client all output
 592          * actually goes to stderr.
 593          */
 594         log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 595             SYSLOG_FACILITY_USER, 1);
 596
 597         /*
 598          * Read per-user configuration file.  Ignore the system wide config
 599          * file if the user specifies a config file on the command line.
 600          */
 601         if (config != NULL) {
 602                 if (!read_config_file(config, host, &options, 0))
 603                         fatal("Can't open user config file %.100s: "
 604                             "%.100s", config, strerror(errno));
 605         } else  {
 606                 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
 607                     _PATH_SSH_USER_CONFFILE);
 608                 (void)read_config_file(buf, host, &options, 1);
 609
 610                 /* Read systemwide configuration file after use config. */
 611                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
 612                     &options, 0);
 613         }
 614
 615         /* Fill configuration defaults. */
 616         fill_default_options(&options);
 617
 618         channel_set_af(options.address_family);
 619
 620         /* reinit */
 621         log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
 622
 623         seed_rng();
 624
 625         if (options.user == NULL)
 626                 options.user = xstrdup(pw->pw_name);
 627
 628         if (options.hostname != NULL)
 629                 host = options.hostname;
 630
 631         /* force lowercase for hostkey matching */
 632         if (options.host_key_alias != NULL) {
 633                 for (p = options.host_key_alias; *p; p++)
 634                         if (isupper(*p))
 635                                 *p = (char)tolower(*p);
 636         }
 637
 638         /* Get default port if port has not been set. */
 639         if (options.port == 0) {
 640                 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
 641                 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
 642         }
 643
 644         if (options.proxy_command != NULL &&
 645             strcmp(options.proxy_command, "none") == 0)
 646                 options.proxy_command = NULL;
 647         if (options.control_path != NULL &&
 648             strcmp(options.control_path, "none") == 0)
 649                 options.control_path = NULL;
 650
 651         if (options.control_path != NULL) {
 652                 char thishost[NI_MAXHOST];
 653
 654                 if (gethostname(thishost, sizeof(thishost)) == -1)
 655                         fatal("gethostname: %s", strerror(errno));
 656                 snprintf(buf, sizeof(buf), "%d", options.port);
 657                 cp = tilde_expand_filename(options.control_path,
 658                     original_real_uid);
 659                 options.control_path = percent_expand(cp, "p", buf, "h", host,
 660                     "r", options.user, "l", thishost, (char *)NULL);
 661                 xfree(cp);
 662         }
 663         if (mux_command != 0 && options.control_path == NULL)
 664                 fatal("No ControlPath specified for \"-O\" command");
 665         if (options.control_path != NULL)
 666                 control_client(options.control_path);
 667
 668         /* Open a connection to the remote host. */
 669         if (ssh_connect(host, &hostaddr, options.port,
 670             options.address_family, options.connection_attempts,
 671 #ifdef HAVE_CYGWIN
 672             options.use_privileged_port,
 673 #else
 674             original_effective_uid == 0 && options.use_privileged_port,
 675 #endif
 676             options.proxy_command) != 0)
 677                 exit(255);
 678
 679         /*
 680          * If we successfully made the connection, load the host private key
 681          * in case we will need it later for combined rsa-rhosts
 682          * authentication. This must be done before releasing extra
 683          * privileges, because the file is only readable by root.
 684          * If we cannot access the private keys, load the public keys
 685          * instead and try to execute the ssh-keysign helper instead.
 686          */
 687         sensitive_data.nkeys = 0;
 688         sensitive_data.keys = NULL;
 689         sensitive_data.external_keysign = 0;
 690         if (options.rhosts_rsa_authentication ||
 691             options.hostbased_authentication) {
 692                 sensitive_data.nkeys = 3;
 693                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
 694                     sizeof(Key));
 695
 696                 PRIV_START;
 697                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
 698                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
 699                 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
 700                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
 701                 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
 702                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
 703                 PRIV_END;
 704
 705                 if (options.hostbased_authentication == 1 &&
 706                     sensitive_data.keys[0] == NULL &&
 707                     sensitive_data.keys[1] == NULL &&
 708                     sensitive_data.keys[2] == NULL) {
 709                         sensitive_data.keys[1] = key_load_public(
 710                             _PATH_HOST_DSA_KEY_FILE, NULL);
 711                         sensitive_data.keys[2] = key_load_public(
 712                             _PATH_HOST_RSA_KEY_FILE, NULL);
 713                         sensitive_data.external_keysign = 1;
 714                 }
 715         }
 716         /*
 717          * Get rid of any extra privileges that we may have.  We will no
 718          * longer need them.  Also, extra privileges could make it very hard
 719          * to read identity files and other non-world-readable files from the
 720          * user's home directory if it happens to be on a NFS volume where
 721          * root is mapped to nobody.
 722          */
 723         if (original_effective_uid == 0) {
 724                 PRIV_START;
 725                 permanently_set_uid(pw);
 726         }
 727
 728         /*
 729          * Now that we are back to our own permissions, create ~/.ssh
 730          * directory if it doesn't already exist.
 731          */
 732         snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
 733         if (stat(buf, &st) < 0)
 734                 if (mkdir(buf, 0700) < 0)
 735                         error("Could not create directory '%.200s'.", buf);
 736
 737         /* load options.identity_files */
 738         load_public_identity_files();
 739
 740         /* Expand ~ in known host file names. */
 741         /* XXX mem-leaks: */
 742         options.system_hostfile =
 743             tilde_expand_filename(options.system_hostfile, original_real_uid);
 744         options.user_hostfile =
 745             tilde_expand_filename(options.user_hostfile, original_real_uid);
 746         options.system_hostfile2 =
 747             tilde_expand_filename(options.system_hostfile2, original_real_uid);
 748         options.user_hostfile2 =
 749             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 750
 751         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 752
 753         /* Log into the remote system.  This never returns if the login fails. */
 754         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw);
 755
 756         /* We no longer need the private host keys.  Clear them now. */
 757         if (sensitive_data.nkeys != 0) {
 758                 for (i = 0; i < sensitive_data.nkeys; i++) {
 759                         if (sensitive_data.keys[i] != NULL) {
 760                                 /* Destroys contents safely */
 761                                 debug3("clear hostkey %d", i);
 762                                 key_free(sensitive_data.keys[i]);
 763                                 sensitive_data.keys[i] = NULL;
 764                         }
 765                 }
 766                 xfree(sensitive_data.keys);
 767         }
 768         for (i = 0; i < options.num_identity_files; i++) {
 769                 if (options.identity_files[i]) {
 770                         xfree(options.identity_files[i]);
 771                         options.identity_files[i] = NULL;
 772                 }
 773                 if (options.identity_keys[i]) {
 774                         key_free(options.identity_keys[i]);
 775                         options.identity_keys[i] = NULL;
 776                 }
 777         }
 778
 779         exit_status = compat20 ? ssh_session2() : ssh_session();
 780         packet_close();
 781
 782         if (options.control_path != NULL && control_fd != -1)
 783                 unlink(options.control_path);
 784
 785         /*
 786          * Send SIGHUP to proxy command if used. We don't wait() in
 787          * case it hangs and instead rely on init to reap the child
 788          */
 789         if (proxy_command_pid > 1)
 790                 kill(proxy_command_pid, SIGHUP);
 791
 792         return exit_status;
 793 }
 794
 795 static void
 796 ssh_init_forwarding(void)
 797 {
 798         int success = 0;
 799         int i;
 800
 801         /* Initiate local TCP/IP port forwardings. */
 802         for (i = 0; i < options.num_local_forwards; i++) {
 803                 debug("Local connections to %.200s:%d forwarded to remote "
 804                     "address %.200s:%d",
 805                     (options.local_forwards[i].listen_host == NULL) ?
 806                     (options.gateway_ports ? "*" : "LOCALHOST") :
 807                     options.local_forwards[i].listen_host,
 808                     options.local_forwards[i].listen_port,
 809                     options.local_forwards[i].connect_host,
 810                     options.local_forwards[i].connect_port);
 811                 success += channel_setup_local_fwd_listener(
 812                     options.local_forwards[i].listen_host,
 813                     options.local_forwards[i].listen_port,
 814                     options.local_forwards[i].connect_host,
 815                     options.local_forwards[i].connect_port,
 816                     options.gateway_ports);
 817         }
 818         if (i > 0 && success == 0)
 819                 error("Could not request local forwarding.");
 820
 821         /* Initiate remote TCP/IP port forwardings. */
 822         for (i = 0; i < options.num_remote_forwards; i++) {
 823                 debug("Remote connections from %.200s:%d forwarded to "
 824                     "local address %.200s:%d",
 825                     (options.remote_forwards[i].listen_host == NULL) ?
 826                     "LOCALHOST" : options.remote_forwards[i].listen_host,
 827                     options.remote_forwards[i].listen_port,
 828                     options.remote_forwards[i].connect_host,
 829                     options.remote_forwards[i].connect_port);
 830                 channel_request_remote_forwarding(
 831                     options.remote_forwards[i].listen_host,
 832                     options.remote_forwards[i].listen_port,
 833                     options.remote_forwards[i].connect_host,
 834                     options.remote_forwards[i].connect_port);
 835         }
 836 }
 837
 838 static void
 839 check_agent_present(void)
 840 {
 841         if (options.forward_agent) {
 842                 /* Clear agent forwarding if we don't have an agent. */
 843                 if (!ssh_agent_present())
 844                         options.forward_agent = 0;
 845         }
 846 }
 847
 848 static int
 849 ssh_session(void)
 850 {
 851         int type;
 852         int interactive = 0;
 853         int have_tty = 0;
 854         struct winsize ws;
 855         char *cp;
 856         const char *display;
 857
 858         /* Enable compression if requested. */
 859         if (options.compression) {
 860                 debug("Requesting compression at level %d.", options.compression_level);
 861
 862                 if (options.compression_level < 1 || options.compression_level > 9)
 863                         fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
 864
 865                 /* Send the request. */
 866                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
 867                 packet_put_int(options.compression_level);
 868                 packet_send();
 869                 packet_write_wait();
 870                 type = packet_read();
 871                 if (type == SSH_SMSG_SUCCESS)
 872                         packet_start_compression(options.compression_level);
 873                 else if (type == SSH_SMSG_FAILURE)
 874                         logit("Warning: Remote host refused compression.");
 875                 else
 876                         packet_disconnect("Protocol error waiting for compression response.");
 877         }
 878         /* Allocate a pseudo tty if appropriate. */
 879         if (tty_flag) {
 880                 debug("Requesting pty.");
 881
 882                 /* Start the packet. */
 883                 packet_start(SSH_CMSG_REQUEST_PTY);
 884
 885                 /* Store TERM in the packet.  There is no limit on the
 886                    length of the string. */
 887                 cp = getenv("TERM");
 888                 if (!cp)
 889                         cp = "";
 890                 packet_put_cstring(cp);
 891
 892                 /* Store window size in the packet. */
 893                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
 894                         memset(&ws, 0, sizeof(ws));
 895                 packet_put_int((u_int)ws.ws_row);
 896                 packet_put_int((u_int)ws.ws_col);
 897                 packet_put_int((u_int)ws.ws_xpixel);
 898                 packet_put_int((u_int)ws.ws_ypixel);
 899
 900                 /* Store tty modes in the packet. */
 901                 tty_make_modes(fileno(stdin), NULL);
 902
 903                 /* Send the packet, and wait for it to leave. */
 904                 packet_send();
 905                 packet_write_wait();
 906
 907                 /* Read response from the server. */
 908                 type = packet_read();
 909                 if (type == SSH_SMSG_SUCCESS) {
 910                         interactive = 1;
 911                         have_tty = 1;
 912                 } else if (type == SSH_SMSG_FAILURE)
 913                         logit("Warning: Remote host failed or refused to allocate a pseudo tty.");
 914                 else
 915                         packet_disconnect("Protocol error waiting for pty request response.");
 916         }
 917         /* Request X11 forwarding if enabled and DISPLAY is set. */
 918         display = getenv("DISPLAY");
 919         if (options.forward_x11 && display != NULL) {
 920                 char *proto, *data;
 921                 /* Get reasonable local authentication information. */
 922                 client_x11_get_proto(display, options.xauth_location,
 923                     options.forward_x11_trusted, &proto, &data);
 924                 /* Request forwarding with authentication spoofing. */
 925                 debug("Requesting X11 forwarding with authentication spoofing.");
 926                 x11_request_forwarding_with_spoofing(0, display, proto, data);
 927
 928                 /* Read response from the server. */
 929                 type = packet_read();
 930                 if (type == SSH_SMSG_SUCCESS) {
 931                         interactive = 1;
 932                 } else if (type == SSH_SMSG_FAILURE) {
 933                         logit("Warning: Remote host denied X11 forwarding.");
 934                 } else {
 935                         packet_disconnect("Protocol error waiting for X11 forwarding");
 936                 }
 937         }
 938         /* Tell the packet module whether this is an interactive session. */
 939         packet_set_interactive(interactive);
 940
 941         /* Request authentication agent forwarding if appropriate. */
 942         check_agent_present();
 943
 944         if (options.forward_agent) {
 945                 debug("Requesting authentication agent forwarding.");
 946                 auth_request_forwarding();
 947
 948                 /* Read response from the server. */
 949                 type = packet_read();
 950                 packet_check_eom();
 951                 if (type != SSH_SMSG_SUCCESS)
 952                         logit("Warning: Remote host denied authentication agent forwarding.");
 953         }
 954
 955         /* Initiate port forwardings. */
 956         ssh_init_forwarding();
 957
 958         /* If requested, let ssh continue in the background. */
 959         if (fork_after_authentication_flag)
 960                 if (daemon(1, 1) < 0)
 961                         fatal("daemon() failed: %.200s", strerror(errno));
 962
 963         /*
 964          * If a command was specified on the command line, execute the
 965          * command now. Otherwise request the server to start a shell.
 966          */
 967         if (buffer_len(&command) > 0) {
 968                 int len = buffer_len(&command);
 969                 if (len > 900)
 970                         len = 900;
 971                 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
 972                 packet_start(SSH_CMSG_EXEC_CMD);
 973                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
 974                 packet_send();
 975                 packet_write_wait();
 976         } else {
 977                 debug("Requesting shell.");
 978                 packet_start(SSH_CMSG_EXEC_SHELL);
 979                 packet_send();
 980                 packet_write_wait();
 981         }
 982
 983         /* Enter the interactive session. */
 984         return client_loop(have_tty, tty_flag ?
 985             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
 986 }
 987
 988 static void
 989 ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt)
 990 {
 991         int id, len;
 992
 993         id = packet_get_int();
 994         len = buffer_len(&command);
 995         if (len > 900)
 996                 len = 900;
 997         packet_check_eom();
 998         if (type == SSH2_MSG_CHANNEL_FAILURE)
 999                 fatal("Request for subsystem '%.*s' failed on channel %d",
1000                     len, (u_char *)buffer_ptr(&command), id);
1001 }
1002
1003 void
1004 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
1005 {
1006         int i;
1007
1008         i = client_global_request_id++;
1009         if (i >= options.num_remote_forwards)
1010                 return;
1011         debug("remote forward %s for: listen %d, connect %s:%d",
1012             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1013             options.remote_forwards[i].listen_port,
1014             options.remote_forwards[i].connect_host,
1015             options.remote_forwards[i].connect_port);
1016         if (type == SSH2_MSG_REQUEST_FAILURE)
1017                 logit("Warning: remote port forwarding failed for listen "
1018                     "port %d", options.remote_forwards[i].listen_port);
1019 }
1020
1021 static void
1022 ssh_control_listener(void)
1023 {
1024         struct sockaddr_un addr;
1025         mode_t old_umask;
1026         int addr_len;
1027
1028         if (options.control_path == NULL ||
1029             options.control_master == SSHCTL_MASTER_NO)
1030                 return;
1031
1032         debug("setting up multiplex master socket");
1033
1034         memset(&addr, '\0', sizeof(addr));
1035         addr.sun_family = AF_UNIX;
1036         addr_len = offsetof(struct sockaddr_un, sun_path) +
1037             strlen(options.control_path) + 1;
1038
1039         if (strlcpy(addr.sun_path, options.control_path,
1040             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1041                 fatal("ControlPath too long");
1042
1043         if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1044                 fatal("%s socket(): %s", __func__, strerror(errno));
1045
1046         old_umask = umask(0177);
1047         if (bind(control_fd, (struct sockaddr *)&addr, addr_len) == -1) {
1048                 control_fd = -1;
1049                 if (errno == EINVAL || errno == EADDRINUSE)
1050                         fatal("ControlSocket %s already exists",
1051                             options.control_path);
1052                 else
1053                         fatal("%s bind(): %s", __func__, strerror(errno));
1054         }
1055         umask(old_umask);
1056
1057         if (listen(control_fd, 64) == -1)
1058                 fatal("%s listen(): %s", __func__, strerror(errno));
1059
1060         set_nonblock(control_fd);
1061 }
1062
1063 /* request pty/x11/agent/tcpfwd/shell for channel */
1064 static void
1065 ssh_session2_setup(int id, void *arg)
1066 {
1067         extern char **environ;
1068         const char *display;
1069         int interactive = tty_flag;
1070
1071         display = getenv("DISPLAY");
1072         if (options.forward_x11 && display != NULL) {
1073                 char *proto, *data;
1074                 /* Get reasonable local authentication information. */
1075                 client_x11_get_proto(display, options.xauth_location,
1076                     options.forward_x11_trusted, &proto, &data);
1077                 /* Request forwarding with authentication spoofing. */
1078                 debug("Requesting X11 forwarding with authentication spoofing.");
1079                 x11_request_forwarding_with_spoofing(id, display, proto, data);
1080                 interactive = 1;
1081                 /* XXX wait for reply */
1082         }
1083
1084         check_agent_present();
1085         if (options.forward_agent) {
1086                 debug("Requesting authentication agent forwarding.");
1087                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1088                 packet_send();
1089         }
1090
1091         if (options.tun_open != SSH_TUNMODE_NO) {
1092                 Channel *c;
1093                 int fd;
1094
1095                 debug("Requesting tun.");
1096                 if ((fd = tun_open(options.tun_local,
1097                     options.tun_open)) >= 0) {
1098                         c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1099                             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1100                             0, "tun", 1);
1101                         c->datagram = 1;
1102 #if defined(SSH_TUN_FILTER)
1103                         if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
1104                                 channel_register_filter(c->self, sys_tun_infilter,
1105                                     sys_tun_outfilter);
1106 #endif
1107                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1108                         packet_put_cstring("tun@openssh.com");
1109                         packet_put_int(c->self);
1110                         packet_put_int(c->local_window_max);
1111                         packet_put_int(c->local_maxpacket);
1112                         packet_put_int(options.tun_open);
1113                         packet_put_int(options.tun_remote);
1114                         packet_send();
1115                 }
1116         }
1117
1118         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1119             NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply);
1120
1121         packet_set_interactive(interactive);
1122 }
1123
1124 /* open new channel for a session */
1125 static int
1126 ssh_session2_open(void)
1127 {
1128         Channel *c;
1129         int window, packetmax, in, out, err;
1130
1131         if (stdin_null_flag) {
1132                 in = open(_PATH_DEVNULL, O_RDONLY);
1133         } else {
1134                 in = dup(STDIN_FILENO);
1135         }
1136         out = dup(STDOUT_FILENO);
1137         err = dup(STDERR_FILENO);
1138
1139         if (in < 0 || out < 0 || err < 0)
1140                 fatal("dup() in/out/err failed");
1141
1142         /* enable nonblocking unless tty */
1143         if (!isatty(in))
1144                 set_nonblock(in);
1145         if (!isatty(out))
1146                 set_nonblock(out);
1147         if (!isatty(err))
1148                 set_nonblock(err);
1149
1150         window = CHAN_SES_WINDOW_DEFAULT;
1151         packetmax = CHAN_SES_PACKET_DEFAULT;
1152         if (tty_flag) {
1153                 window >>= 1;
1154                 packetmax >>= 1;
1155         }
1156         c = channel_new(
1157             "session", SSH_CHANNEL_OPENING, in, out, err,
1158             window, packetmax, CHAN_EXTENDED_WRITE,
1159             "client-session", /*nonblock*/0);
1160
1161         debug3("ssh_session2_open: channel_new: %d", c->self);
1162
1163         channel_send_open(c->self);
1164         if (!no_shell_flag)
1165                 channel_register_confirm(c->self, ssh_session2_setup, NULL);
1166
1167         return c->self;
1168 }
1169
1170 static int
1171 ssh_session2(void)
1172 {
1173         int id = -1;
1174
1175         /* XXX should be pre-session */
1176         ssh_init_forwarding();
1177         ssh_control_listener();
1178
1179         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1180                 id = ssh_session2_open();
1181
1182         /* Execute a local command */
1183         if (options.local_command != NULL &&
1184             options.permit_local_command)
1185                 ssh_local_cmd(options.local_command);
1186
1187         /* If requested, let ssh continue in the background. */
1188         if (fork_after_authentication_flag)
1189                 if (daemon(1, 1) < 0)
1190                         fatal("daemon() failed: %.200s", strerror(errno));
1191
1192         return client_loop(tty_flag, tty_flag ?
1193             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1194 }
1195
1196 static void
1197 load_public_identity_files(void)
1198 {
1199         char *filename, *cp, thishost[NI_MAXHOST];
1200         int i = 0;
1201         Key *public;
1202         struct passwd *pw;
1203 #ifdef SMARTCARD
1204         Key **keys;
1205
1206         if (options.smartcard_device != NULL &&
1207             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1208             (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL ) {
1209                 int count = 0;
1210                 for (i = 0; keys[i] != NULL; i++) {
1211                         count++;
1212                         memmove(&options.identity_files[1], &options.identity_files[0],
1213                             sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1214                         memmove(&options.identity_keys[1], &options.identity_keys[0],
1215                             sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1216                         options.num_identity_files++;
1217                         options.identity_keys[0] = keys[i];
1218                         options.identity_files[0] = sc_get_key_label(keys[i]);
1219                 }
1220                 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1221                         options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1222                 i = count;
1223                 xfree(keys);
1224         }
1225 #endif /* SMARTCARD */
1226         if ((pw = getpwuid(original_real_uid)) == NULL)
1227                 fatal("load_public_identity_files: getpwuid failed");
1228         if (gethostname(thishost, sizeof(thishost)) == -1)
1229                 fatal("load_public_identity_files: gethostname: %s",
1230                     strerror(errno));
1231         for (; i < options.num_identity_files; i++) {
1232                 cp = tilde_expand_filename(options.identity_files[i],
1233                     original_real_uid);
1234                 filename = percent_expand(cp, "d", pw->pw_dir,
1235                     "u", pw->pw_name, "l", thishost, "h", host,
1236                     "r", options.user, (char *)NULL);
1237                 xfree(cp);
1238                 public = key_load_public(filename, NULL);
1239                 debug("identity file %s type %d", filename,
1240                     public ? public->type : -1);
1241                 xfree(options.identity_files[i]);
1242                 options.identity_files[i] = filename;
1243                 options.identity_keys[i] = public;
1244         }
1245 }
1246
1247 static void
1248 control_client_sighandler(int signo)
1249 {
1250         control_client_terminate = signo;
1251 }
1252
1253 static void
1254 control_client_sigrelay(int signo)
1255 {
1256         if (control_server_pid > 1)
1257                 kill(control_server_pid, signo);
1258 }
1259
1260 static int
1261 env_permitted(char *env)
1262 {
1263         int i;
1264         char name[1024], *cp;
1265
1266         if (strlcpy(name, env, sizeof(name)) >= sizeof(name))
1267                 fatal("env_permitted: name too long");
1268         if ((cp = strchr(name, '=')) == NULL)
1269                 return (0);
1270
1271         *cp = '\0';
1272
1273         for (i = 0; i < options.num_send_env; i++)
1274                 if (match_pattern(name, options.send_env[i]))
1275                         return (1);
1276
1277         return (0);
1278 }
1279
1280 static void
1281 control_client(const char *path)
1282 {
1283         struct sockaddr_un addr;
1284         int i, r, fd, sock, exitval, num_env, addr_len;
1285         Buffer m;
1286         char *term;
1287         extern char **environ;
1288         u_int  flags;
1289
1290         if (mux_command == 0)
1291                 mux_command = SSHMUX_COMMAND_OPEN;
1292
1293         switch (options.control_master) {
1294         case SSHCTL_MASTER_AUTO:
1295         case SSHCTL_MASTER_AUTO_ASK:
1296                 debug("auto-mux: Trying existing master");
1297                 /* FALLTHROUGH */
1298         case SSHCTL_MASTER_NO:
1299                 break;
1300         default:
1301                 return;
1302         }
1303
1304         memset(&addr, '\0', sizeof(addr));
1305         addr.sun_family = AF_UNIX;
1306         addr_len = offsetof(struct sockaddr_un, sun_path) +
1307             strlen(path) + 1;
1308
1309         if (strlcpy(addr.sun_path, path,
1310             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1311                 fatal("ControlPath too long");
1312
1313         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1314                 fatal("%s socket(): %s", __func__, strerror(errno));
1315
1316         if (connect(sock, (struct sockaddr *)&addr, addr_len) == -1) {
1317                 if (mux_command != SSHMUX_COMMAND_OPEN) {
1318                         fatal("Control socket connect(%.100s): %s", path,
1319                             strerror(errno));
1320                 }
1321                 if (errno == ENOENT)
1322                         debug("Control socket \"%.100s\" does not exist", path);
1323                 else {
1324                         error("Control socket connect(%.100s): %s", path,
1325                             strerror(errno));
1326                 }
1327                 close(sock);
1328                 return;
1329         }
1330
1331         if (stdin_null_flag) {
1332                 if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1333                         fatal("open(/dev/null): %s", strerror(errno));
1334                 if (dup2(fd, STDIN_FILENO) == -1)
1335                         fatal("dup2: %s", strerror(errno));
1336                 if (fd > STDERR_FILENO)
1337                         close(fd);
1338         }
1339
1340         term = getenv("TERM");
1341
1342         flags = 0;
1343         if (tty_flag)
1344                 flags |= SSHMUX_FLAG_TTY;
1345         if (subsystem_flag)
1346                 flags |= SSHMUX_FLAG_SUBSYS;
1347         if (options.forward_x11)
1348                 flags |= SSHMUX_FLAG_X11_FWD;
1349         if (options.forward_agent)
1350                 flags |= SSHMUX_FLAG_AGENT_FWD;
1351
1352         buffer_init(&m);
1353
1354         /* Send our command to server */
1355         buffer_put_int(&m, mux_command);
1356         buffer_put_int(&m, flags);
1357         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1358                 fatal("%s: msg_send", __func__);
1359         buffer_clear(&m);
1360
1361         /* Get authorisation status and PID of controlee */
1362         if (ssh_msg_recv(sock, &m) == -1)
1363                 fatal("%s: msg_recv", __func__);
1364         if (buffer_get_char(&m) != SSHMUX_VER)
1365                 fatal("%s: wrong version", __func__);
1366         if (buffer_get_int(&m) != 1)
1367                 fatal("Connection to master denied");
1368         control_server_pid = buffer_get_int(&m);
1369
1370         buffer_clear(&m);
1371
1372         switch (mux_command) {
1373         case SSHMUX_COMMAND_ALIVE_CHECK:
1374                 fprintf(stderr, "Master running (pid=%d)\r\n",
1375                     control_server_pid);
1376                 exit(0);
1377         case SSHMUX_COMMAND_TERMINATE:
1378                 fprintf(stderr, "Exit request sent.\r\n");
1379                 exit(0);
1380         case SSHMUX_COMMAND_OPEN:
1381                 /* continue below */
1382                 break;
1383         default:
1384                 fatal("silly mux_command %d", mux_command);
1385         }
1386
1387         /* SSHMUX_COMMAND_OPEN */
1388         buffer_put_cstring(&m, term ? term : "");
1389         buffer_append(&command, "\0", 1);
1390         buffer_put_cstring(&m, buffer_ptr(&command));
1391
1392         if (options.num_send_env == 0 || environ == NULL) {
1393                 buffer_put_int(&m, 0);
1394         } else {
1395                 /* Pass environment */
1396                 num_env = 0;
1397                 for (i = 0; environ[i] != NULL; i++)
1398                         if (env_permitted(environ[i]))
1399                                 num_env++; /* Count */
1400
1401                 buffer_put_int(&m, num_env);
1402
1403                 for (i = 0; environ[i] != NULL && num_env >= 0; i++)
1404                         if (env_permitted(environ[i])) {
1405                                 num_env--;
1406                                 buffer_put_cstring(&m, environ[i]);
1407                         }
1408         }
1409
1410         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1411                 fatal("%s: msg_send", __func__);
1412
1413         mm_send_fd(sock, STDIN_FILENO);
1414         mm_send_fd(sock, STDOUT_FILENO);
1415         mm_send_fd(sock, STDERR_FILENO);
1416
1417         /* Wait for reply, so master has a chance to gather ttymodes */
1418         buffer_clear(&m);
1419         if (ssh_msg_recv(sock, &m) == -1)
1420                 fatal("%s: msg_recv", __func__);
1421         if (buffer_get_char(&m) != SSHMUX_VER)
1422                 fatal("%s: wrong version", __func__);
1423         buffer_free(&m);
1424
1425         signal(SIGHUP, control_client_sighandler);
1426         signal(SIGINT, control_client_sighandler);
1427         signal(SIGTERM, control_client_sighandler);
1428         signal(SIGWINCH, control_client_sigrelay);
1429
1430         if (tty_flag)
1431                 enter_raw_mode();
1432
1433         /* Stick around until the controlee closes the client_fd */
1434         exitval = 0;
1435         for (;!control_client_terminate;) {
1436                 r = read(sock, &exitval, sizeof(exitval));
1437                 if (r == 0) {
1438                         debug2("Received EOF from master");
1439                         break;
1440                 }
1441                 if (r > 0)
1442                         debug2("Received exit status from master %d", exitval);
1443                 if (r == -1 && errno != EINTR)
1444                         fatal("%s: read %s", __func__, strerror(errno));
1445         }
1446
1447         if (control_client_terminate)
1448                 debug2("Exiting on signal %d", control_client_terminate);
1449
1450         close(sock);
1451
1452         leave_raw_mode();
1453
1454         if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1455                 fprintf(stderr, "Connection to master closed.\r\n");
1456
1457         exit(exitval);
1458 }