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 1.224 2004/07/28 09:40:29 markus 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
  75 #ifdef SMARTCARD
  76 #include "scard.h"
  77 #endif
  78
  79 extern char *__progname;
  80
  81 /* Flag indicating whether debug mode is on.  This can be set on the command line. */
  82 int debug_flag = 0;
  83
  84 /* Flag indicating whether a tty should be allocated */
  85 int tty_flag = 0;
  86 int no_tty_flag = 0;
  87 int force_tty_flag = 0;
  88
  89 /* don't exec a shell */
  90 int no_shell_flag = 0;
  91
  92 /*
  93  * Flag indicating that nothing should be read from stdin.  This can be set
  94  * on the command line.
  95  */
  96 int stdin_null_flag = 0;
  97
  98 /*
  99  * Flag indicating that ssh should fork after authentication.  This is useful
 100  * so that the passphrase can be entered manually, and then ssh goes to the
 101  * background.
 102  */
 103 int fork_after_authentication_flag = 0;
 104
 105 /*
 106  * General data structure for command line options and options configurable
 107  * in configuration files.  See readconf.h.
 108  */
 109 Options options;
 110
 111 /* optional user configfile */
 112 char *config = NULL;
 113
 114 /*
 115  * Name of the host we are connecting to.  This is the name given on the
 116  * command line, or the HostName specified for the user-supplied name in a
 117  * configuration file.
 118  */
 119 char *host;
 120
 121 /* socket address the host resolves to */
 122 struct sockaddr_storage hostaddr;
 123
 124 /* Private host keys. */
 125 Sensitive sensitive_data;
 126
 127 /* Original real UID. */
 128 uid_t original_real_uid;
 129 uid_t original_effective_uid;
 130
 131 /* command to be executed */
 132 Buffer command;
 133
 134 /* Should we execute a command or invoke a subsystem? */
 135 int subsystem_flag = 0;
 136
 137 /* # of replies received for global requests */
 138 static int client_global_request_id = 0;
 139
 140 /* pid of proxycommand child process */
 141 pid_t proxy_command_pid = 0;
 142
 143 /* fd to control socket */
 144 int control_fd = -1;
 145
 146 /* Only used in control client mode */
 147 volatile sig_atomic_t control_client_terminate = 0;
 148 u_int control_server_pid = 0;
 149
 150 /* Prints a help message to the user.  This function never returns. */
 151
 152 static void
 153 usage(void)
 154 {
 155         fprintf(stderr,
 156 "usage: ssh [-1246AaCfghkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
 157 "           [-D port] [-e escape_char] [-F configfile] [-i identity_file]\n"
 158 "           [-L port:host:hostport] [-l login_name] [-m mac_spec] [-o option]\n"
 159 "           [-p port] [-R port:host:hostport] [-S ctl] [user@]hostname [command]\n"
 160         );
 161         exit(1);
 162 }
 163
 164 static int ssh_session(void);
 165 static int ssh_session2(void);
 166 static void load_public_identity_files(void);
 167 static void control_client(const char *path);
 168
 169 /*
 170  * Main program for the ssh client.
 171  */
 172 int
 173 main(int ac, char **av)
 174 {
 175         int i, opt, exit_status;
 176         u_short fwd_port, fwd_host_port;
 177         char sfwd_port[6], sfwd_host_port[6];
 178         char *p, *cp, *line, buf[256];
 179         struct stat st;
 180         struct passwd *pw;
 181         int dummy;
 182         extern int optind, optreset;
 183         extern char *optarg;
 184
 185         __progname = ssh_get_progname(av[0]);
 186         init_rng();
 187
 188         /*
 189          * Save the original real uid.  It will be needed later (uid-swapping
 190          * may clobber the real uid).
 191          */
 192         original_real_uid = getuid();
 193         original_effective_uid = geteuid();
 194
 195         /*
 196          * Use uid-swapping to give up root privileges for the duration of
 197          * option processing.  We will re-instantiate the rights when we are
 198          * ready to create the privileged port, and will permanently drop
 199          * them when the port has been created (actually, when the connection
 200          * has been made, as we may need to create the port several times).
 201          */
 202         PRIV_END;
 203
 204 #ifdef HAVE_SETRLIMIT
 205         /* If we are installed setuid root be careful to not drop core. */
 206         if (original_real_uid != original_effective_uid) {
 207                 struct rlimit rlim;
 208                 rlim.rlim_cur = rlim.rlim_max = 0;
 209                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 210                         fatal("setrlimit failed: %.100s", strerror(errno));
 211         }
 212 #endif
 213         /* Get user data. */
 214         pw = getpwuid(original_real_uid);
 215         if (!pw) {
 216                 logit("You don't exist, go away!");
 217                 exit(1);
 218         }
 219         /* Take a copy of the returned structure. */
 220         pw = pwcopy(pw);
 221
 222         /*
 223          * Set our umask to something reasonable, as some files are created
 224          * with the default umask.  This will make them world-readable but
 225          * writable only by the owner, which is ok for all files for which we
 226          * don't set the modes explicitly.
 227          */
 228         umask(022);
 229
 230         /* Initialize option structure to indicate that no values have been set. */
 231         initialize_options(&options);
 232
 233         /* Parse command-line arguments. */
 234         host = NULL;
 235
 236 again:
 237         while ((opt = getopt(ac, av,
 238             "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNPR:S:TVXY")) != -1) {
 239                 switch (opt) {
 240                 case '1':
 241                         options.protocol = SSH_PROTO_1;
 242                         break;
 243                 case '2':
 244                         options.protocol = SSH_PROTO_2;
 245                         break;
 246                 case '4':
 247                         options.address_family = AF_INET;
 248                         break;
 249                 case '6':
 250                         options.address_family = AF_INET6;
 251                         break;
 252                 case 'n':
 253                         stdin_null_flag = 1;
 254                         break;
 255                 case 'f':
 256                         fork_after_authentication_flag = 1;
 257                         stdin_null_flag = 1;
 258                         break;
 259                 case 'x':
 260                         options.forward_x11 = 0;
 261                         break;
 262                 case 'X':
 263                         options.forward_x11 = 1;
 264                         break;
 265                 case 'Y':
 266                         options.forward_x11 = 1;
 267                         options.forward_x11_trusted = 1;
 268                         break;
 269                 case 'g':
 270                         options.gateway_ports = 1;
 271                         break;
 272                 case 'P':       /* deprecated */
 273                         options.use_privileged_port = 0;
 274                         break;
 275                 case 'a':
 276                         options.forward_agent = 0;
 277                         break;
 278                 case 'A':
 279                         options.forward_agent = 1;
 280                         break;
 281                 case 'k':
 282                         options.gss_deleg_creds = 0;
 283                         break;
 284                 case 'i':
 285                         if (stat(optarg, &st) < 0) {
 286                                 fprintf(stderr, "Warning: Identity file %s "
 287                                     "does not exist.\n", optarg);
 288                                 break;
 289                         }
 290                         if (options.num_identity_files >=
 291                             SSH_MAX_IDENTITY_FILES)
 292                                 fatal("Too many identity files specified "
 293                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
 294                         options.identity_files[options.num_identity_files++] =
 295                             xstrdup(optarg);
 296                         break;
 297                 case 'I':
 298 #ifdef SMARTCARD
 299                         options.smartcard_device = xstrdup(optarg);
 300 #else
 301                         fprintf(stderr, "no support for smartcards.\n");
 302 #endif
 303                         break;
 304                 case 't':
 305                         if (tty_flag)
 306                                 force_tty_flag = 1;
 307                         tty_flag = 1;
 308                         break;
 309                 case 'v':
 310                         if (debug_flag == 0) {
 311                                 debug_flag = 1;
 312                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 313                         } else {
 314                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 315                                         options.log_level++;
 316                                 break;
 317                         }
 318                         /* fallthrough */
 319                 case 'V':
 320                         fprintf(stderr, "%s, %s\n",
 321                             SSH_VERSION, SSLeay_version(SSLEAY_VERSION));
 322                         if (opt == 'V')
 323                                 exit(0);
 324                         break;
 325                 case 'q':
 326                         options.log_level = SYSLOG_LEVEL_QUIET;
 327                         break;
 328                 case 'e':
 329                         if (optarg[0] == '^' && optarg[2] == 0 &&
 330                             (u_char) optarg[1] >= 64 &&
 331                             (u_char) optarg[1] < 128)
 332                                 options.escape_char = (u_char) optarg[1] & 31;
 333                         else if (strlen(optarg) == 1)
 334                                 options.escape_char = (u_char) optarg[0];
 335                         else if (strcmp(optarg, "none") == 0)
 336                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 337                         else {
 338                                 fprintf(stderr, "Bad escape character '%s'.\n",
 339                                     optarg);
 340                                 exit(1);
 341                         }
 342                         break;
 343                 case 'c':
 344                         if (ciphers_valid(optarg)) {
 345                                 /* SSH2 only */
 346                                 options.ciphers = xstrdup(optarg);
 347                                 options.cipher = SSH_CIPHER_INVALID;
 348                         } else {
 349                                 /* SSH1 only */
 350                                 options.cipher = cipher_number(optarg);
 351                                 if (options.cipher == -1) {
 352                                         fprintf(stderr,
 353                                             "Unknown cipher type '%s'\n",
 354                                             optarg);
 355                                         exit(1);
 356                                 }
 357                                 if (options.cipher == SSH_CIPHER_3DES)
 358                                         options.ciphers = "3des-cbc";
 359                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 360                                         options.ciphers = "blowfish-cbc";
 361                                 else
 362                                         options.ciphers = (char *)-1;
 363                         }
 364                         break;
 365                 case 'm':
 366                         if (mac_valid(optarg))
 367                                 options.macs = xstrdup(optarg);
 368                         else {
 369                                 fprintf(stderr, "Unknown mac type '%s'\n",
 370                                     optarg);
 371                                 exit(1);
 372                         }
 373                         break;
 374                 case 'M':
 375                         options.control_master =
 376                             (options.control_master >= 1) ? 2 : 1;
 377                         break;
 378                 case 'p':
 379                         options.port = a2port(optarg);
 380                         if (options.port == 0) {
 381                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 382                                 exit(1);
 383                         }
 384                         break;
 385                 case 'l':
 386                         options.user = optarg;
 387                         break;
 388
 389                 case 'L':
 390                 case 'R':
 391                         if (sscanf(optarg, "%5[0123456789]:%255[^:]:%5[0123456789]",
 392                             sfwd_port, buf, sfwd_host_port) != 3 &&
 393                             sscanf(optarg, "%5[0123456789]/%255[^/]/%5[0123456789]",
 394                             sfwd_port, buf, sfwd_host_port) != 3) {
 395                                 fprintf(stderr,
 396                                     "Bad forwarding specification '%s'\n",
 397                                     optarg);
 398                                 usage();
 399                                 /* NOTREACHED */
 400                         }
 401                         if ((fwd_port = a2port(sfwd_port)) == 0 ||
 402                             (fwd_host_port = a2port(sfwd_host_port)) == 0) {
 403                                 fprintf(stderr,
 404                                     "Bad forwarding port(s) '%s'\n", optarg);
 405                                 exit(1);
 406                         }
 407                         if (opt == 'L')
 408                                 add_local_forward(&options, fwd_port, buf,
 409                                     fwd_host_port);
 410                         else if (opt == 'R')
 411                                 add_remote_forward(&options, fwd_port, buf,
 412                                     fwd_host_port);
 413                         break;
 414
 415                 case 'D':
 416                         fwd_port = a2port(optarg);
 417                         if (fwd_port == 0) {
 418                                 fprintf(stderr, "Bad dynamic port '%s'\n",
 419                                     optarg);
 420                                 exit(1);
 421                         }
 422                         add_local_forward(&options, fwd_port, "socks", 0);
 423                         break;
 424
 425                 case 'C':
 426                         options.compression = 1;
 427                         break;
 428                 case 'N':
 429                         no_shell_flag = 1;
 430                         no_tty_flag = 1;
 431                         break;
 432                 case 'T':
 433                         no_tty_flag = 1;
 434                         break;
 435                 case 'o':
 436                         dummy = 1;
 437                         line = xstrdup(optarg);
 438                         if (process_config_line(&options, host ? host : "",
 439                             line, "command-line", 0, &dummy) != 0)
 440                                 exit(1);
 441                         xfree(line);
 442                         break;
 443                 case 's':
 444                         subsystem_flag = 1;
 445                         break;
 446                 case 'S':
 447                         if (options.control_path != NULL)
 448                                 free(options.control_path);
 449                         options.control_path = xstrdup(optarg);
 450                         break;
 451                 case 'b':
 452                         options.bind_address = optarg;
 453                         break;
 454                 case 'F':
 455                         config = optarg;
 456                         break;
 457                 default:
 458                         usage();
 459                 }
 460         }
 461
 462         ac -= optind;
 463         av += optind;
 464
 465         if (ac > 0 && !host && **av != '-') {
 466                 if (strrchr(*av, '@')) {
 467                         p = xstrdup(*av);
 468                         cp = strrchr(p, '@');
 469                         if (cp == NULL || cp == p)
 470                                 usage();
 471                         options.user = p;
 472                         *cp = '\0';
 473                         host = ++cp;
 474                 } else
 475                         host = *av;
 476                 if (ac > 1) {
 477                         optind = optreset = 1;
 478                         goto again;
 479                 }
 480                 ac--, av++;
 481         }
 482
 483         /* Check that we got a host name. */
 484         if (!host)
 485                 usage();
 486
 487         SSLeay_add_all_algorithms();
 488         ERR_load_crypto_strings();
 489
 490         /* Initialize the command to execute on remote host. */
 491         buffer_init(&command);
 492
 493         /*
 494          * Save the command to execute on the remote host in a buffer. There
 495          * is no limit on the length of the command, except by the maximum
 496          * packet size.  Also sets the tty flag if there is no command.
 497          */
 498         if (!ac) {
 499                 /* No command specified - execute shell on a tty. */
 500                 tty_flag = 1;
 501                 if (subsystem_flag) {
 502                         fprintf(stderr,
 503                             "You must specify a subsystem to invoke.\n");
 504                         usage();
 505                 }
 506         } else {
 507                 /* A command has been specified.  Store it into the buffer. */
 508                 for (i = 0; i < ac; i++) {
 509                         if (i)
 510                                 buffer_append(&command, " ", 1);
 511                         buffer_append(&command, av[i], strlen(av[i]));
 512                 }
 513         }
 514
 515         /* Cannot fork to background if no command. */
 516         if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
 517                 fatal("Cannot fork into background without a command to execute.");
 518
 519         /* Allocate a tty by default if no command specified. */
 520         if (buffer_len(&command) == 0)
 521                 tty_flag = 1;
 522
 523         /* Force no tty */
 524         if (no_tty_flag)
 525                 tty_flag = 0;
 526         /* Do not allocate a tty if stdin is not a tty. */
 527         if (!isatty(fileno(stdin)) && !force_tty_flag) {
 528                 if (tty_flag)
 529                         logit("Pseudo-terminal will not be allocated because stdin is not a terminal.");
 530                 tty_flag = 0;
 531         }
 532
 533         /*
 534          * Initialize "log" output.  Since we are the client all output
 535          * actually goes to stderr.
 536          */
 537         log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 538             SYSLOG_FACILITY_USER, 1);
 539
 540         /*
 541          * Read per-user configuration file.  Ignore the system wide config
 542          * file if the user specifies a config file on the command line.
 543          */
 544         if (config != NULL) {
 545                 if (!read_config_file(config, host, &options, 0))
 546                         fatal("Can't open user config file %.100s: "
 547                             "%.100s", config, strerror(errno));
 548         } else  {
 549                 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
 550                     _PATH_SSH_USER_CONFFILE);
 551                 (void)read_config_file(buf, host, &options, 1);
 552
 553                 /* Read systemwide configuration file after use config. */
 554                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
 555                     &options, 0);
 556         }
 557
 558         /* Fill configuration defaults. */
 559         fill_default_options(&options);
 560
 561         channel_set_af(options.address_family);
 562
 563         /* reinit */
 564         log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
 565
 566         seed_rng();
 567
 568         if (options.user == NULL)
 569                 options.user = xstrdup(pw->pw_name);
 570
 571         if (options.hostname != NULL)
 572                 host = options.hostname;
 573
 574         /* force lowercase for hostkey matching */
 575         if (options.host_key_alias != NULL) {
 576                 for (p = options.host_key_alias; *p; p++)
 577                         if (isupper(*p))
 578                                 *p = tolower(*p);
 579         }
 580
 581         if (options.proxy_command != NULL &&
 582             strcmp(options.proxy_command, "none") == 0)
 583                 options.proxy_command = NULL;
 584
 585         if (options.control_path != NULL) {
 586                 options.control_path = tilde_expand_filename(
 587                    options.control_path, original_real_uid);
 588         }
 589         if (options.control_path != NULL && options.control_master == 0)
 590                 control_client(options.control_path); /* This doesn't return */
 591
 592         /* Open a connection to the remote host. */
 593         if (ssh_connect(host, &hostaddr, options.port,
 594             options.address_family, options.connection_attempts,
 595 #ifdef HAVE_CYGWIN
 596             options.use_privileged_port,
 597 #else
 598             original_effective_uid == 0 && options.use_privileged_port,
 599 #endif
 600             options.proxy_command) != 0)
 601                 exit(1);
 602
 603         /*
 604          * If we successfully made the connection, load the host private key
 605          * in case we will need it later for combined rsa-rhosts
 606          * authentication. This must be done before releasing extra
 607          * privileges, because the file is only readable by root.
 608          * If we cannot access the private keys, load the public keys
 609          * instead and try to execute the ssh-keysign helper instead.
 610          */
 611         sensitive_data.nkeys = 0;
 612         sensitive_data.keys = NULL;
 613         sensitive_data.external_keysign = 0;
 614         if (options.rhosts_rsa_authentication ||
 615             options.hostbased_authentication) {
 616                 sensitive_data.nkeys = 3;
 617                 sensitive_data.keys = xmalloc(sensitive_data.nkeys *
 618                     sizeof(Key));
 619
 620                 PRIV_START;
 621                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
 622                     _PATH_HOST_KEY_FILE, "", NULL);
 623                 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
 624                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
 625                 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
 626                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
 627                 PRIV_END;
 628
 629                 if (options.hostbased_authentication == 1 &&
 630                     sensitive_data.keys[0] == NULL &&
 631                     sensitive_data.keys[1] == NULL &&
 632                     sensitive_data.keys[2] == NULL) {
 633                         sensitive_data.keys[1] = key_load_public(
 634                             _PATH_HOST_DSA_KEY_FILE, NULL);
 635                         sensitive_data.keys[2] = key_load_public(
 636                             _PATH_HOST_RSA_KEY_FILE, NULL);
 637                         sensitive_data.external_keysign = 1;
 638                 }
 639         }
 640         /*
 641          * Get rid of any extra privileges that we may have.  We will no
 642          * longer need them.  Also, extra privileges could make it very hard
 643          * to read identity files and other non-world-readable files from the
 644          * user's home directory if it happens to be on a NFS volume where
 645          * root is mapped to nobody.
 646          */
 647         seteuid(original_real_uid);
 648         setuid(original_real_uid);
 649
 650         /*
 651          * Now that we are back to our own permissions, create ~/.ssh
 652          * directory if it doesn\'t already exist.
 653          */
 654         snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
 655         if (stat(buf, &st) < 0)
 656                 if (mkdir(buf, 0700) < 0)
 657                         error("Could not create directory '%.200s'.", buf);
 658
 659         /* load options.identity_files */
 660         load_public_identity_files();
 661
 662         /* Expand ~ in known host file names. */
 663         /* XXX mem-leaks: */
 664         options.system_hostfile =
 665             tilde_expand_filename(options.system_hostfile, original_real_uid);
 666         options.user_hostfile =
 667             tilde_expand_filename(options.user_hostfile, original_real_uid);
 668         options.system_hostfile2 =
 669             tilde_expand_filename(options.system_hostfile2, original_real_uid);
 670         options.user_hostfile2 =
 671             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 672
 673         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 674
 675         /* Log into the remote system.  This never returns if the login fails. */
 676         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw);
 677
 678         /* We no longer need the private host keys.  Clear them now. */
 679         if (sensitive_data.nkeys != 0) {
 680                 for (i = 0; i < sensitive_data.nkeys; i++) {
 681                         if (sensitive_data.keys[i] != NULL) {
 682                                 /* Destroys contents safely */
 683                                 debug3("clear hostkey %d", i);
 684                                 key_free(sensitive_data.keys[i]);
 685                                 sensitive_data.keys[i] = NULL;
 686                         }
 687                 }
 688                 xfree(sensitive_data.keys);
 689         }
 690         for (i = 0; i < options.num_identity_files; i++) {
 691                 if (options.identity_files[i]) {
 692                         xfree(options.identity_files[i]);
 693                         options.identity_files[i] = NULL;
 694                 }
 695                 if (options.identity_keys[i]) {
 696                         key_free(options.identity_keys[i]);
 697                         options.identity_keys[i] = NULL;
 698                 }
 699         }
 700
 701         exit_status = compat20 ? ssh_session2() : ssh_session();
 702         packet_close();
 703
 704         if (options.control_path != NULL && control_fd != -1)
 705                 unlink(options.control_path);
 706
 707         /*
 708          * Send SIGHUP to proxy command if used. We don't wait() in
 709          * case it hangs and instead rely on init to reap the child
 710          */
 711         if (proxy_command_pid > 1)
 712                 kill(proxy_command_pid, SIGHUP);
 713
 714         return exit_status;
 715 }
 716
 717 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
 718
 719 static void
 720 x11_get_proto(char **_proto, char **_data)
 721 {
 722         char cmd[1024];
 723         char line[512];
 724         char xdisplay[512];
 725         static char proto[512], data[512];
 726         FILE *f;
 727         int got_data = 0, generated = 0, do_unlink = 0, i;
 728         char *display, *xauthdir, *xauthfile;
 729         struct stat st;
 730
 731         xauthdir = xauthfile = NULL;
 732         *_proto = proto;
 733         *_data = data;
 734         proto[0] = data[0] = '\0';
 735
 736         if (!options.xauth_location ||
 737             (stat(options.xauth_location, &st) == -1)) {
 738                 debug("No xauth program.");
 739         } else {
 740                 if ((display = getenv("DISPLAY")) == NULL) {
 741                         debug("x11_get_proto: DISPLAY not set");
 742                         return;
 743                 }
 744                 /*
 745                  * Handle FamilyLocal case where $DISPLAY does
 746                  * not match an authorization entry.  For this we
 747                  * just try "xauth list unix:displaynum.screennum".
 748                  * XXX: "localhost" match to determine FamilyLocal
 749                  *      is not perfect.
 750                  */
 751                 if (strncmp(display, "localhost:", 10) == 0) {
 752                         snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
 753                             display + 10);
 754                         display = xdisplay;
 755                 }
 756                 if (options.forward_x11_trusted == 0) {
 757                         xauthdir = xmalloc(MAXPATHLEN);
 758                         xauthfile = xmalloc(MAXPATHLEN);
 759                         strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
 760                         if (mkdtemp(xauthdir) != NULL) {
 761                                 do_unlink = 1;
 762                                 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile",
 763                                     xauthdir);
 764                                 snprintf(cmd, sizeof(cmd),
 765                                     "%s -f %s generate %s " SSH_X11_PROTO
 766                                     " untrusted timeout 1200 2>" _PATH_DEVNULL,
 767                                     options.xauth_location, xauthfile, display);
 768                                 debug2("x11_get_proto: %s", cmd);
 769                                 if (system(cmd) == 0)
 770                                         generated = 1;
 771                         }
 772                 }
 773                 snprintf(cmd, sizeof(cmd),
 774                     "%s %s%s list %s . 2>" _PATH_DEVNULL,
 775                     options.xauth_location,
 776                     generated ? "-f " : "" ,
 777                     generated ? xauthfile : "",
 778                     display);
 779                 debug2("x11_get_proto: %s", cmd);
 780                 f = popen(cmd, "r");
 781                 if (f && fgets(line, sizeof(line), f) &&
 782                     sscanf(line, "%*s %511s %511s", proto, data) == 2)
 783                         got_data = 1;
 784                 if (f)
 785                         pclose(f);
 786         }
 787
 788         if (do_unlink) {
 789                 unlink(xauthfile);
 790                 rmdir(xauthdir);
 791         }
 792         if (xauthdir)
 793                 xfree(xauthdir);
 794         if (xauthfile)
 795                 xfree(xauthfile);
 796
 797         /*
 798          * If we didn't get authentication data, just make up some
 799          * data.  The forwarding code will check the validity of the
 800          * response anyway, and substitute this data.  The X11
 801          * server, however, will ignore this fake data and use
 802          * whatever authentication mechanisms it was using otherwise
 803          * for the local connection.
 804          */
 805         if (!got_data) {
 806                 u_int32_t rnd = 0;
 807
 808                 logit("Warning: No xauth data; "
 809                     "using fake authentication data for X11 forwarding.");
 810                 strlcpy(proto, SSH_X11_PROTO, sizeof proto);
 811                 for (i = 0; i < 16; i++) {
 812                         if (i % 4 == 0)
 813                                 rnd = arc4random();
 814                         snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
 815                             rnd & 0xff);
 816                         rnd >>= 8;
 817                 }
 818         }
 819 }
 820
 821 static void
 822 ssh_init_forwarding(void)
 823 {
 824         int success = 0;
 825         int i;
 826
 827         /* Initiate local TCP/IP port forwardings. */
 828         for (i = 0; i < options.num_local_forwards; i++) {
 829                 debug("Connections to local port %d forwarded to remote address %.200s:%d",
 830                     options.local_forwards[i].port,
 831                     options.local_forwards[i].host,
 832                     options.local_forwards[i].host_port);
 833                 success += channel_setup_local_fwd_listener(
 834                     options.local_forwards[i].port,
 835                     options.local_forwards[i].host,
 836                     options.local_forwards[i].host_port,
 837                     options.gateway_ports);
 838         }
 839         if (i > 0 && success == 0)
 840                 error("Could not request local forwarding.");
 841
 842         /* Initiate remote TCP/IP port forwardings. */
 843         for (i = 0; i < options.num_remote_forwards; i++) {
 844                 debug("Connections to remote port %d forwarded to local address %.200s:%d",
 845                     options.remote_forwards[i].port,
 846                     options.remote_forwards[i].host,
 847                     options.remote_forwards[i].host_port);
 848                 channel_request_remote_forwarding(
 849                     options.remote_forwards[i].port,
 850                     options.remote_forwards[i].host,
 851                     options.remote_forwards[i].host_port);
 852         }
 853 }
 854
 855 static void
 856 check_agent_present(void)
 857 {
 858         if (options.forward_agent) {
 859                 /* Clear agent forwarding if we don\'t have an agent. */
 860                 if (!ssh_agent_present())
 861                         options.forward_agent = 0;
 862         }
 863 }
 864
 865 static int
 866 ssh_session(void)
 867 {
 868         int type;
 869         int interactive = 0;
 870         int have_tty = 0;
 871         struct winsize ws;
 872         char *cp;
 873
 874         /* Enable compression if requested. */
 875         if (options.compression) {
 876                 debug("Requesting compression at level %d.", options.compression_level);
 877
 878                 if (options.compression_level < 1 || options.compression_level > 9)
 879                         fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
 880
 881                 /* Send the request. */
 882                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
 883                 packet_put_int(options.compression_level);
 884                 packet_send();
 885                 packet_write_wait();
 886                 type = packet_read();
 887                 if (type == SSH_SMSG_SUCCESS)
 888                         packet_start_compression(options.compression_level);
 889                 else if (type == SSH_SMSG_FAILURE)
 890                         logit("Warning: Remote host refused compression.");
 891                 else
 892                         packet_disconnect("Protocol error waiting for compression response.");
 893         }
 894         /* Allocate a pseudo tty if appropriate. */
 895         if (tty_flag) {
 896                 debug("Requesting pty.");
 897
 898                 /* Start the packet. */
 899                 packet_start(SSH_CMSG_REQUEST_PTY);
 900
 901                 /* Store TERM in the packet.  There is no limit on the
 902                    length of the string. */
 903                 cp = getenv("TERM");
 904                 if (!cp)
 905                         cp = "";
 906                 packet_put_cstring(cp);
 907
 908                 /* Store window size in the packet. */
 909                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
 910                         memset(&ws, 0, sizeof(ws));
 911                 packet_put_int(ws.ws_row);
 912                 packet_put_int(ws.ws_col);
 913                 packet_put_int(ws.ws_xpixel);
 914                 packet_put_int(ws.ws_ypixel);
 915
 916                 /* Store tty modes in the packet. */
 917                 tty_make_modes(fileno(stdin), NULL);
 918
 919                 /* Send the packet, and wait for it to leave. */
 920                 packet_send();
 921                 packet_write_wait();
 922
 923                 /* Read response from the server. */
 924                 type = packet_read();
 925                 if (type == SSH_SMSG_SUCCESS) {
 926                         interactive = 1;
 927                         have_tty = 1;
 928                 } else if (type == SSH_SMSG_FAILURE)
 929                         logit("Warning: Remote host failed or refused to allocate a pseudo tty.");
 930                 else
 931                         packet_disconnect("Protocol error waiting for pty request response.");
 932         }
 933         /* Request X11 forwarding if enabled and DISPLAY is set. */
 934         if (options.forward_x11 && getenv("DISPLAY") != NULL) {
 935                 char *proto, *data;
 936                 /* Get reasonable local authentication information. */
 937                 x11_get_proto(&proto, &data);
 938                 /* Request forwarding with authentication spoofing. */
 939                 debug("Requesting X11 forwarding with authentication spoofing.");
 940                 x11_request_forwarding_with_spoofing(0, proto, data);
 941
 942                 /* Read response from the server. */
 943                 type = packet_read();
 944                 if (type == SSH_SMSG_SUCCESS) {
 945                         interactive = 1;
 946                 } else if (type == SSH_SMSG_FAILURE) {
 947                         logit("Warning: Remote host denied X11 forwarding.");
 948                 } else {
 949                         packet_disconnect("Protocol error waiting for X11 forwarding");
 950                 }
 951         }
 952         /* Tell the packet module whether this is an interactive session. */
 953         packet_set_interactive(interactive);
 954
 955         /* Request authentication agent forwarding if appropriate. */
 956         check_agent_present();
 957
 958         if (options.forward_agent) {
 959                 debug("Requesting authentication agent forwarding.");
 960                 auth_request_forwarding();
 961
 962                 /* Read response from the server. */
 963                 type = packet_read();
 964                 packet_check_eom();
 965                 if (type != SSH_SMSG_SUCCESS)
 966                         logit("Warning: Remote host denied authentication agent forwarding.");
 967         }
 968
 969         /* Initiate port forwardings. */
 970         ssh_init_forwarding();
 971
 972         /* If requested, let ssh continue in the background. */
 973         if (fork_after_authentication_flag)
 974                 if (daemon(1, 1) < 0)
 975                         fatal("daemon() failed: %.200s", strerror(errno));
 976
 977         /*
 978          * If a command was specified on the command line, execute the
 979          * command now. Otherwise request the server to start a shell.
 980          */
 981         if (buffer_len(&command) > 0) {
 982                 int len = buffer_len(&command);
 983                 if (len > 900)
 984                         len = 900;
 985                 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
 986                 packet_start(SSH_CMSG_EXEC_CMD);
 987                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
 988                 packet_send();
 989                 packet_write_wait();
 990         } else {
 991                 debug("Requesting shell.");
 992                 packet_start(SSH_CMSG_EXEC_SHELL);
 993                 packet_send();
 994                 packet_write_wait();
 995         }
 996
 997         /* Enter the interactive session. */
 998         return client_loop(have_tty, tty_flag ?
 999             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1000 }
1001
1002 static void
1003 ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt)
1004 {
1005         int id, len;
1006
1007         id = packet_get_int();
1008         len = buffer_len(&command);
1009         if (len > 900)
1010                 len = 900;
1011         packet_check_eom();
1012         if (type == SSH2_MSG_CHANNEL_FAILURE)
1013                 fatal("Request for subsystem '%.*s' failed on channel %d",
1014                     len, (u_char *)buffer_ptr(&command), id);
1015 }
1016
1017 void
1018 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
1019 {
1020         int i;
1021
1022         i = client_global_request_id++;
1023         if (i >= options.num_remote_forwards)
1024                 return;
1025         debug("remote forward %s for: listen %d, connect %s:%d",
1026             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1027             options.remote_forwards[i].port,
1028             options.remote_forwards[i].host,
1029             options.remote_forwards[i].host_port);
1030         if (type == SSH2_MSG_REQUEST_FAILURE)
1031                 logit("Warning: remote port forwarding failed for listen port %d",
1032                     options.remote_forwards[i].port);
1033 }
1034
1035 static void
1036 ssh_control_listener(void)
1037 {
1038         struct sockaddr_un addr;
1039         mode_t old_umask;
1040         int addr_len;
1041
1042         if (options.control_path == NULL || options.control_master <= 0)
1043                 return;
1044
1045         memset(&addr, '\0', sizeof(addr));
1046         addr.sun_family = AF_UNIX;
1047         addr_len = offsetof(struct sockaddr_un, sun_path) +
1048             strlen(options.control_path) + 1;
1049
1050         if (strlcpy(addr.sun_path, options.control_path,
1051             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1052                 fatal("ControlPath too long");
1053
1054         if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1055                 fatal("%s socket(): %s\n", __func__, strerror(errno));
1056
1057         old_umask = umask(0177);
1058         if (bind(control_fd, (struct sockaddr*)&addr, addr_len) == -1) {
1059                 control_fd = -1;
1060                 if (errno == EINVAL)
1061                         fatal("ControlSocket %s already exists",
1062                             options.control_path);
1063                 else
1064                         fatal("%s bind(): %s\n", __func__, strerror(errno));
1065         }
1066         umask(old_umask);
1067
1068         if (listen(control_fd, 64) == -1)
1069                 fatal("%s listen(): %s\n", __func__, strerror(errno));
1070
1071         set_nonblock(control_fd);
1072 }
1073
1074 /* request pty/x11/agent/tcpfwd/shell for channel */
1075 static void
1076 ssh_session2_setup(int id, void *arg)
1077 {
1078         extern char **environ;
1079
1080         int interactive = tty_flag;
1081         if (options.forward_x11 && getenv("DISPLAY") != NULL) {
1082                 char *proto, *data;
1083                 /* Get reasonable local authentication information. */
1084                 x11_get_proto(&proto, &data);
1085                 /* Request forwarding with authentication spoofing. */
1086                 debug("Requesting X11 forwarding with authentication spoofing.");
1087                 x11_request_forwarding_with_spoofing(id, proto, data);
1088                 interactive = 1;
1089                 /* XXX wait for reply */
1090         }
1091
1092         check_agent_present();
1093         if (options.forward_agent) {
1094                 debug("Requesting authentication agent forwarding.");
1095                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1096                 packet_send();
1097         }
1098
1099         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1100             NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply);
1101
1102         packet_set_interactive(interactive);
1103 }
1104
1105 /* open new channel for a session */
1106 static int
1107 ssh_session2_open(void)
1108 {
1109         Channel *c;
1110         int window, packetmax, in, out, err;
1111
1112         if (stdin_null_flag) {
1113                 in = open(_PATH_DEVNULL, O_RDONLY);
1114         } else {
1115                 in = dup(STDIN_FILENO);
1116         }
1117         out = dup(STDOUT_FILENO);
1118         err = dup(STDERR_FILENO);
1119
1120         if (in < 0 || out < 0 || err < 0)
1121                 fatal("dup() in/out/err failed");
1122
1123         /* enable nonblocking unless tty */
1124         if (!isatty(in))
1125                 set_nonblock(in);
1126         if (!isatty(out))
1127                 set_nonblock(out);
1128         if (!isatty(err))
1129                 set_nonblock(err);
1130
1131         window = CHAN_SES_WINDOW_DEFAULT;
1132         packetmax = CHAN_SES_PACKET_DEFAULT;
1133         if (tty_flag) {
1134                 window >>= 1;
1135                 packetmax >>= 1;
1136         }
1137         c = channel_new(
1138             "session", SSH_CHANNEL_OPENING, in, out, err,
1139             window, packetmax, CHAN_EXTENDED_WRITE,
1140             "client-session", /*nonblock*/0);
1141
1142         debug3("ssh_session2_open: channel_new: %d", c->self);
1143
1144         channel_send_open(c->self);
1145         if (!no_shell_flag)
1146                 channel_register_confirm(c->self, ssh_session2_setup, NULL);
1147
1148         return c->self;
1149 }
1150
1151 static int
1152 ssh_session2(void)
1153 {
1154         int id = -1;
1155
1156         /* XXX should be pre-session */
1157         ssh_init_forwarding();
1158         ssh_control_listener();
1159
1160         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1161                 id = ssh_session2_open();
1162
1163         /* If requested, let ssh continue in the background. */
1164         if (fork_after_authentication_flag)
1165                 if (daemon(1, 1) < 0)
1166                         fatal("daemon() failed: %.200s", strerror(errno));
1167
1168         return client_loop(tty_flag, tty_flag ?
1169             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1170 }
1171
1172 static void
1173 load_public_identity_files(void)
1174 {
1175         char *filename;
1176         int i = 0;
1177         Key *public;
1178 #ifdef SMARTCARD
1179         Key **keys;
1180
1181         if (options.smartcard_device != NULL &&
1182             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1183             (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL ) {
1184                 int count = 0;
1185                 for (i = 0; keys[i] != NULL; i++) {
1186                         count++;
1187                         memmove(&options.identity_files[1], &options.identity_files[0],
1188                             sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1189                         memmove(&options.identity_keys[1], &options.identity_keys[0],
1190                             sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1191                         options.num_identity_files++;
1192                         options.identity_keys[0] = keys[i];
1193                         options.identity_files[0] = sc_get_key_label(keys[i]);
1194                 }
1195                 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1196                         options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1197                 i = count;
1198                 xfree(keys);
1199         }
1200 #endif /* SMARTCARD */
1201         for (; i < options.num_identity_files; i++) {
1202                 filename = tilde_expand_filename(options.identity_files[i],
1203                     original_real_uid);
1204                 public = key_load_public(filename, NULL);
1205                 debug("identity file %s type %d", filename,
1206                     public ? public->type : -1);
1207                 xfree(options.identity_files[i]);
1208                 options.identity_files[i] = filename;
1209                 options.identity_keys[i] = public;
1210         }
1211 }
1212
1213 static void
1214 control_client_sighandler(int signo)
1215 {
1216         control_client_terminate = signo;
1217 }
1218
1219 static void
1220 control_client_sigrelay(int signo)
1221 {
1222         if (control_server_pid > 1)
1223                 kill(control_server_pid, signo);
1224 }
1225
1226 static int
1227 env_permitted(char *env)
1228 {
1229         int i;
1230         char name[1024], *cp;
1231
1232         strlcpy(name, env, sizeof(name));
1233         if ((cp = strchr(name, '=')) == NULL)
1234                 return (0);
1235
1236         *cp = '\0';
1237
1238         for (i = 0; i < options.num_send_env; i++)
1239                 if (match_pattern(name, options.send_env[i]))
1240                         return (1);
1241
1242         return (0);
1243 }
1244
1245 static void
1246 control_client(const char *path)
1247 {
1248         struct sockaddr_un addr;
1249         int i, r, sock, exitval, num_env, addr_len;
1250         Buffer m;
1251         char *cp;
1252         extern char **environ;
1253
1254         memset(&addr, '\0', sizeof(addr));
1255         addr.sun_family = AF_UNIX;
1256         addr_len = offsetof(struct sockaddr_un, sun_path) +
1257             strlen(path) + 1;
1258
1259         if (strlcpy(addr.sun_path, path,
1260             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1261                 fatal("ControlPath too long");
1262
1263         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1264                 fatal("%s socket(): %s", __func__, strerror(errno));
1265
1266         if (connect(sock, (struct sockaddr*)&addr, addr_len) == -1)
1267                 fatal("Couldn't connect to %s: %s", path, strerror(errno));
1268
1269         if ((cp = getenv("TERM")) == NULL)
1270                 cp = "";
1271
1272         buffer_init(&m);
1273
1274         /* Get PID of controlee */
1275         if (ssh_msg_recv(sock, &m) == -1)
1276                 fatal("%s: msg_recv", __func__);
1277         if (buffer_get_char(&m) != 0)
1278                 fatal("%s: wrong version", __func__);
1279         /* Connection allowed? */
1280         if (buffer_get_int(&m) != 1)
1281                 fatal("Connection to master denied");
1282         control_server_pid = buffer_get_int(&m);
1283
1284         buffer_clear(&m);
1285         buffer_put_int(&m, tty_flag);
1286         buffer_put_int(&m, subsystem_flag);
1287         buffer_put_cstring(&m, cp);
1288
1289         buffer_append(&command, "\0", 1);
1290         buffer_put_cstring(&m, buffer_ptr(&command));
1291
1292         if (options.num_send_env == 0 || environ == NULL) {
1293                 buffer_put_int(&m, 0);
1294         } else {
1295                 /* Pass environment */
1296                 num_env = 0;
1297                 for (i = 0; environ[i] != NULL; i++)
1298                         if (env_permitted(environ[i]))
1299                                 num_env++; /* Count */
1300
1301                 buffer_put_int(&m, num_env);
1302
1303                 for (i = 0; environ[i] != NULL && num_env >= 0; i++)
1304                         if (env_permitted(environ[i])) {
1305                                 num_env--;
1306                                 buffer_put_cstring(&m, environ[i]);
1307                         }
1308         }
1309
1310         if (ssh_msg_send(sock, /* version */0, &m) == -1)
1311                 fatal("%s: msg_send", __func__);
1312
1313         mm_send_fd(sock, STDIN_FILENO);
1314         mm_send_fd(sock, STDOUT_FILENO);
1315         mm_send_fd(sock, STDERR_FILENO);
1316
1317         /* Wait for reply, so master has a chance to gather ttymodes */
1318         buffer_clear(&m);
1319         if (ssh_msg_recv(sock, &m) == -1)
1320                 fatal("%s: msg_recv", __func__);
1321         if (buffer_get_char(&m) != 0)
1322                 fatal("%s: master returned error", __func__);
1323         buffer_free(&m);
1324
1325         signal(SIGINT, control_client_sighandler);
1326         signal(SIGTERM, control_client_sighandler);
1327         signal(SIGWINCH, control_client_sigrelay);
1328
1329         if (tty_flag)
1330                 enter_raw_mode();
1331
1332         /* Stick around until the controlee closes the client_fd */
1333         exitval = 0;
1334         for (;!control_client_terminate;) {
1335                 r = read(sock, &exitval, sizeof(exitval));
1336                 if (r == 0) {
1337                         debug2("Received EOF from master");
1338                         break;
1339                 }
1340                 if (r > 0)
1341                         debug2("Received exit status from master %d", exitval);
1342                 if (r == -1 && errno != EINTR)
1343                         fatal("%s: read %s", __func__, strerror(errno));
1344         }
1345
1346         if (control_client_terminate)
1347                 debug2("Exiting on signal %d", control_client_terminate);
1348
1349         close(sock);
1350
1351         leave_raw_mode();
1352
1353         if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1354                 fprintf(stderr, "Connection to master closed.\r\n");
1355
1356         exit(exitval);
1357 }