openssh/ssh.c

   1 /* $OpenBSD: ssh.c,v 1.309 2008/01/19 20:51:26 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * Ssh client program.  This program can be used to log into a remote machine.
   7  * The software supports strong authentication, encryption, and forwarding
   8  * of X11, TCP/IP, and authentication connections.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * Copyright (c) 1999 Niels Provos.  All rights reserved.
  17  * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl.  All rights reserved.
  18  *
  19  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
  20  * in Canada (German citizen).
  21  *
  22  * Redistribution and use in source and binary forms, with or without
  23  * modification, are permitted provided that the following conditions
  24  * are met:
  25  * 1. Redistributions of source code must retain the above copyright
  26  *    notice, this list of conditions and the following disclaimer.
  27  * 2. Redistributions in binary form must reproduce the above copyright
  28  *    notice, this list of conditions and the following disclaimer in the
  29  *    documentation and/or other materials provided with the distribution.
  30  *
  31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  32  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  33  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  34  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  35  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  36  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  37  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  38  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  39  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  40  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  41  */
  42
  43 #include "includes.h"
  44
  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/socket.h>
  52 #include <sys/un.h>
  53
  54 #include <ctype.h>
  55 #include <errno.h>
  56 #include <fcntl.h>
  57 #include <netdb.h>
  58 #ifdef HAVE_PATHS_H
  59 #include <paths.h>
  60 #endif
  61 #include <pwd.h>
  62 #include <signal.h>
  63 #include <stdarg.h>
  64 #include <stddef.h>
  65 #include <stdio.h>
  66 #include <stdlib.h>
  67 #include <string.h>
  68 #include <unistd.h>
  69
  70 #include <netinet/in.h>
  71 #include <arpa/inet.h>
  72
  73 #include <openssl/evp.h>
  74 #include <openssl/err.h>
  75 #include "openbsd-compat/openssl-compat.h"
  76
  77 #include "xmalloc.h"
  78 #include "ssh.h"
  79 #include "ssh1.h"
  80 #include "ssh2.h"
  81 #include "compat.h"
  82 #include "cipher.h"
  83 #include "packet.h"
  84 #include "buffer.h"
  85 #include "channels.h"
  86 #include "key.h"
  87 #include "authfd.h"
  88 #include "authfile.h"
  89 #include "pathnames.h"
  90 #include "dispatch.h"
  91 #include "clientloop.h"
  92 #include "log.h"
  93 #include "readconf.h"
  94 #include "sshconnect.h"
  95 #include "misc.h"
  96 #include "kex.h"
  97 #include "mac.h"
  98 #include "sshpty.h"
  99 #include "match.h"
 100 #include "msg.h"
 101 #include "monitor_fdpass.h"
 102 #include "uidswap.h"
 103 #include "version.h"
 104
 105 #ifdef SMARTCARD
 106 #include "scard.h"
 107 #endif
 108
 109 extern char *__progname;
 110
 111 /* Flag indicating whether debug mode is on.  This can be set on the command line. */
 112 int debug_flag = 0;
 113
 114 /* Flag indicating whether a tty should be allocated */
 115 int tty_flag = 0;
 116 int no_tty_flag = 0;
 117 int force_tty_flag = 0;
 118
 119 /* don't exec a shell */
 120 int no_shell_flag = 0;
 121
 122 /*
 123  * Flag indicating that nothing should be read from stdin.  This can be set
 124  * on the command line.
 125  */
 126 int stdin_null_flag = 0;
 127
 128 /*
 129  * Flag indicating that ssh should fork after authentication.  This is useful
 130  * so that the passphrase can be entered manually, and then ssh goes to the
 131  * background.
 132  */
 133 int fork_after_authentication_flag = 0;
 134
 135 /*
 136  * General data structure for command line options and options configurable
 137  * in configuration files.  See readconf.h.
 138  */
 139 Options options;
 140
 141 /* optional user configfile */
 142 char *config = NULL;
 143
 144 /*
 145  * Name of the host we are connecting to.  This is the name given on the
 146  * command line, or the HostName specified for the user-supplied name in a
 147  * configuration file.
 148  */
 149 char *host;
 150
 151 /* socket address the host resolves to */
 152 struct sockaddr_storage hostaddr;
 153
 154 /* Private host keys. */
 155 Sensitive sensitive_data;
 156
 157 /* Original real UID. */
 158 uid_t original_real_uid;
 159 uid_t original_effective_uid;
 160
 161 /* command to be executed */
 162 Buffer command;
 163
 164 /* Should we execute a command or invoke a subsystem? */
 165 int subsystem_flag = 0;
 166
 167 /* # of replies received for global requests */
 168 static int client_global_request_id = 0;
 169
 170 /* pid of proxycommand child process */
 171 pid_t proxy_command_pid = 0;
 172
 173 /* fd to control socket */
 174 int control_fd = -1;
 175
 176 /* Multiplexing control command */
 177 static u_int mux_command = 0;
 178
 179 /* Only used in control client mode */
 180 volatile sig_atomic_t control_client_terminate = 0;
 181 u_int control_server_pid = 0;
 182
 183 /* Prints a help message to the user.  This function never returns. */
 184
 185 static void
 186 usage(void)
 187 {
 188         fprintf(stderr,
 189 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
 190 "           [-D [bind_address:]port] [-e escape_char] [-F configfile]\n"
 191 "           [-i identity_file] [-L [bind_address:]port:host:hostport]\n"
 192 "           [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n"
 193 "           [-R [bind_address:]port:host:hostport] [-S ctl_path]\n"
 194 "           [-w local_tun[:remote_tun]] [user@]hostname [command]\n"
 195         );
 196         exit(255);
 197 }
 198
 199 static int ssh_session(void);
 200 static int ssh_session2(void);
 201 static void load_public_identity_files(void);
 202 static void control_client(const char *path);
 203
 204 /*
 205  * Main program for the ssh client.
 206  */
 207 int
 208 main(int ac, char **av)
 209 {
 210         int i, opt, exit_status;
 211         char *p, *cp, *line, buf[256];
 212         struct stat st;
 213         struct passwd *pw;
 214         int dummy, timeout_ms;
 215         extern int optind, optreset;
 216         extern char *optarg;
 217         struct servent *sp;
 218         Forward fwd;
 219
 220         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 221         sanitise_stdfd();
 222
 223         __progname = ssh_get_progname(av[0]);
 224         init_rng();
 225
 226         /*
 227          * Save the original real uid.  It will be needed later (uid-swapping
 228          * may clobber the real uid).
 229          */
 230         original_real_uid = getuid();
 231         original_effective_uid = geteuid();
 232
 233         /*
 234          * Use uid-swapping to give up root privileges for the duration of
 235          * option processing.  We will re-instantiate the rights when we are
 236          * ready to create the privileged port, and will permanently drop
 237          * them when the port has been created (actually, when the connection
 238          * has been made, as we may need to create the port several times).
 239          */
 240         PRIV_END;
 241
 242 #ifdef HAVE_SETRLIMIT
 243         /* If we are installed setuid root be careful to not drop core. */
 244         if (original_real_uid != original_effective_uid) {
 245                 struct rlimit rlim;
 246                 rlim.rlim_cur = rlim.rlim_max = 0;
 247                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 248                         fatal("setrlimit failed: %.100s", strerror(errno));
 249         }
 250 #endif
 251         /* Get user data. */
 252         pw = getpwuid(original_real_uid);
 253         if (!pw) {
 254                 logit("You don't exist, go away!");
 255                 exit(255);
 256         }
 257         /* Take a copy of the returned structure. */
 258         pw = pwcopy(pw);
 259
 260         /*
 261          * Set our umask to something reasonable, as some files are created
 262          * with the default umask.  This will make them world-readable but
 263          * writable only by the owner, which is ok for all files for which we
 264          * don't set the modes explicitly.
 265          */
 266         umask(022);
 267
 268         /* Initialize option structure to indicate that no values have been set. */
 269         initialize_options(&options);
 270
 271         /* Parse command-line arguments. */
 272         host = NULL;
 273
 274  again:
 275         while ((opt = getopt(ac, av,
 276             "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:KL:MNO:PR:S:TVw:XY")) != -1) {
 277                 switch (opt) {
 278                 case '1':
 279                         options.protocol = SSH_PROTO_1;
 280                         break;
 281                 case '2':
 282                         options.protocol = SSH_PROTO_2;
 283                         break;
 284                 case '4':
 285                         options.address_family = AF_INET;
 286                         break;
 287                 case '6':
 288                         options.address_family = AF_INET6;
 289                         break;
 290                 case 'n':
 291                         stdin_null_flag = 1;
 292                         break;
 293                 case 'f':
 294                         fork_after_authentication_flag = 1;
 295                         stdin_null_flag = 1;
 296                         break;
 297                 case 'x':
 298                         options.forward_x11 = 0;
 299                         break;
 300                 case 'X':
 301                         options.forward_x11 = 1;
 302                         break;
 303                 case 'Y':
 304                         options.forward_x11 = 1;
 305                         options.forward_x11_trusted = 1;
 306                         break;
 307                 case 'g':
 308                         options.gateway_ports = 1;
 309                         break;
 310                 case 'O':
 311                         if (strcmp(optarg, "check") == 0)
 312                                 mux_command = SSHMUX_COMMAND_ALIVE_CHECK;
 313                         else if (strcmp(optarg, "exit") == 0)
 314                                 mux_command = SSHMUX_COMMAND_TERMINATE;
 315                         else
 316                                 fatal("Invalid multiplex command.");
 317                         break;
 318                 case 'P':       /* deprecated */
 319                         options.use_privileged_port = 0;
 320                         break;
 321                 case 'a':
 322                         options.forward_agent = 0;
 323                         break;
 324                 case 'A':
 325                         options.forward_agent = 1;
 326                         break;
 327                 case 'k':
 328                         options.gss_deleg_creds = 0;
 329                         break;
 330                 case 'K':
 331                         options.gss_authentication = 1;
 332                         options.gss_deleg_creds = 1;
 333                         break;
 334                 case 'i':
 335                         if (stat(optarg, &st) < 0) {
 336                                 fprintf(stderr, "Warning: Identity file %s "
 337                                     "not accessible: %s.\n", optarg,
 338                                     strerror(errno));
 339                                 break;
 340                         }
 341                         if (options.num_identity_files >=
 342                             SSH_MAX_IDENTITY_FILES)
 343                                 fatal("Too many identity files specified "
 344                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
 345                         options.identity_files[options.num_identity_files++] =
 346                             xstrdup(optarg);
 347                         break;
 348                 case 'I':
 349 #ifdef SMARTCARD
 350                         options.smartcard_device = xstrdup(optarg);
 351 #else
 352                         fprintf(stderr, "no support for smartcards.\n");
 353 #endif
 354                         break;
 355                 case 't':
 356                         if (tty_flag)
 357                                 force_tty_flag = 1;
 358                         tty_flag = 1;
 359                         break;
 360                 case 'v':
 361                         if (debug_flag == 0) {
 362                                 debug_flag = 1;
 363                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 364                         } else {
 365                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 366                                         options.log_level++;
 367                                 break;
 368                         }
 369                         /* FALLTHROUGH */
 370                 case 'V':
 371                         fprintf(stderr, "%s, %s\n",
 372                             SSH_RELEASE, SSLeay_version(SSLEAY_VERSION));
 373                         if (opt == 'V')
 374                                 exit(0);
 375                         break;
 376                 case 'w':
 377                         if (options.tun_open == -1)
 378                                 options.tun_open = SSH_TUNMODE_DEFAULT;
 379                         options.tun_local = a2tun(optarg, &options.tun_remote);
 380                         if (options.tun_local == SSH_TUNID_ERR) {
 381                                 fprintf(stderr, "Bad tun device '%s'\n", optarg);
 382                                 exit(255);
 383                         }
 384                         break;
 385                 case 'q':
 386                         options.log_level = SYSLOG_LEVEL_QUIET;
 387                         break;
 388                 case 'e':
 389                         if (optarg[0] == '^' && optarg[2] == 0 &&
 390                             (u_char) optarg[1] >= 64 &&
 391                             (u_char) optarg[1] < 128)
 392                                 options.escape_char = (u_char) optarg[1] & 31;
 393                         else if (strlen(optarg) == 1)
 394                                 options.escape_char = (u_char) optarg[0];
 395                         else if (strcmp(optarg, "none") == 0)
 396                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 397                         else {
 398                                 fprintf(stderr, "Bad escape character '%s'.\n",
 399                                     optarg);
 400                                 exit(255);
 401                         }
 402                         break;
 403                 case 'c':
 404                         if (ciphers_valid(optarg)) {
 405                                 /* SSH2 only */
 406                                 options.ciphers = xstrdup(optarg);
 407                                 options.cipher = SSH_CIPHER_INVALID;
 408                         } else {
 409                                 /* SSH1 only */
 410                                 options.cipher = cipher_number(optarg);
 411                                 if (options.cipher == -1) {
 412                                         fprintf(stderr,
 413                                             "Unknown cipher type '%s'\n",
 414                                             optarg);
 415                                         exit(255);
 416                                 }
 417                                 if (options.cipher == SSH_CIPHER_3DES)
 418                                         options.ciphers = "3des-cbc";
 419                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 420                                         options.ciphers = "blowfish-cbc";
 421                                 else
 422                                         options.ciphers = (char *)-1;
 423                         }
 424                         break;
 425                 case 'm':
 426                         if (mac_valid(optarg))
 427                                 options.macs = xstrdup(optarg);
 428                         else {
 429                                 fprintf(stderr, "Unknown mac type '%s'\n",
 430                                     optarg);
 431                                 exit(255);
 432                         }
 433                         break;
 434                 case 'M':
 435                         if (options.control_master == SSHCTL_MASTER_YES)
 436                                 options.control_master = SSHCTL_MASTER_ASK;
 437                         else
 438                                 options.control_master = SSHCTL_MASTER_YES;
 439                         break;
 440                 case 'p':
 441                         options.port = a2port(optarg);
 442                         if (options.port == 0) {
 443                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 444                                 exit(255);
 445                         }
 446                         break;
 447                 case 'l':
 448                         options.user = optarg;
 449                         break;
 450
 451                 case 'L':
 452                         if (parse_forward(&fwd, optarg))
 453                                 add_local_forward(&options, &fwd);
 454                         else {
 455                                 fprintf(stderr,
 456                                     "Bad local forwarding specification '%s'\n",
 457                                     optarg);
 458                                 exit(255);
 459                         }
 460                         break;
 461
 462                 case 'R':
 463                         if (parse_forward(&fwd, optarg)) {
 464                                 add_remote_forward(&options, &fwd);
 465                         } else {
 466                                 fprintf(stderr,
 467                                     "Bad remote forwarding specification "
 468                                     "'%s'\n", optarg);
 469                                 exit(255);
 470                         }
 471                         break;
 472
 473                 case 'D':
 474                         cp = p = xstrdup(optarg);
 475                         memset(&fwd, '\0', sizeof(fwd));
 476                         fwd.connect_host = "socks";
 477                         if ((fwd.listen_host = hpdelim(&cp)) == NULL) {
 478                                 fprintf(stderr, "Bad dynamic forwarding "
 479                                     "specification '%.100s'\n", optarg);
 480                                 exit(255);
 481                         }
 482                         if (cp != NULL) {
 483                                 fwd.listen_port = a2port(cp);
 484                                 fwd.listen_host = cleanhostname(fwd.listen_host);
 485                         } else {
 486                                 fwd.listen_port = a2port(fwd.listen_host);
 487                                 fwd.listen_host = NULL;
 488                         }
 489
 490                         if (fwd.listen_port == 0) {
 491                                 fprintf(stderr, "Bad dynamic port '%s'\n",
 492                                     optarg);
 493                                 exit(255);
 494                         }
 495                         add_local_forward(&options, &fwd);
 496                         xfree(p);
 497                         break;
 498
 499                 case 'C':
 500                         options.compression = 1;
 501                         break;
 502                 case 'N':
 503                         no_shell_flag = 1;
 504                         no_tty_flag = 1;
 505                         break;
 506                 case 'T':
 507                         no_tty_flag = 1;
 508                         /* ensure that the user doesn't try to backdoor a */
 509                         /* null cipher switch on an interactive session */
 510                         /* so explicitly disable it no matter what */
 511                         options.none_switch=0;
 512                         break;
 513                 case 'o':
 514                         dummy = 1;
 515                         line = xstrdup(optarg);
 516                         if (process_config_line(&options, host ? host : "",
 517                             line, "command-line", 0, &dummy) != 0)
 518                                 exit(255);
 519                         xfree(line);
 520                         break;
 521                 case 's':
 522                         subsystem_flag = 1;
 523                         break;
 524                 case 'S':
 525                         if (options.control_path != NULL)
 526                                 free(options.control_path);
 527                         options.control_path = xstrdup(optarg);
 528                         break;
 529                 case 'b':
 530                         options.bind_address = optarg;
 531                         break;
 532                 case 'F':
 533                         config = optarg;
 534                         break;
 535                 default:
 536                         usage();
 537                 }
 538         }
 539
 540         ac -= optind;
 541         av += optind;
 542
 543         if (ac > 0 && !host && **av != '-') {
 544                 if (strrchr(*av, '@')) {
 545                         p = xstrdup(*av);
 546                         cp = strrchr(p, '@');
 547                         if (cp == NULL || cp == p)
 548                                 usage();
 549                         options.user = p;
 550                         *cp = '\0';
 551                         host = ++cp;
 552                 } else
 553                         host = *av;
 554                 if (ac > 1) {
 555                         optind = optreset = 1;
 556                         goto again;
 557                 }
 558                 ac--, av++;
 559         }
 560
 561         /* Check that we got a host name. */
 562         if (!host)
 563                 usage();
 564
 565         SSLeay_add_all_algorithms();
 566         ERR_load_crypto_strings();
 567
 568         /* Initialize the command to execute on remote host. */
 569         buffer_init(&command);
 570
 571         /*
 572          * Save the command to execute on the remote host in a buffer. There
 573          * is no limit on the length of the command, except by the maximum
 574          * packet size.  Also sets the tty flag if there is no command.
 575          */
 576         if (!ac) {
 577                 /* No command specified - execute shell on a tty. */
 578                 tty_flag = 1;
 579                 if (subsystem_flag) {
 580                         fprintf(stderr,
 581                             "You must specify a subsystem to invoke.\n");
 582                         usage();
 583                 }
 584         } else {
 585                 /* A command has been specified.  Store it into the buffer. */
 586                 for (i = 0; i < ac; i++) {
 587                         if (i)
 588                                 buffer_append(&command, " ", 1);
 589                         buffer_append(&command, av[i], strlen(av[i]));
 590                 }
 591         }
 592
 593         /* Cannot fork to background if no command. */
 594         if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
 595                 fatal("Cannot fork into background without a command to execute.");
 596
 597         /* Allocate a tty by default if no command specified. */
 598         if (buffer_len(&command) == 0)
 599                 tty_flag = 1;
 600
 601         /* Force no tty */
 602         if (no_tty_flag)
 603                 tty_flag = 0;
 604         /* Do not allocate a tty if stdin is not a tty. */
 605         if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) {
 606                 if (tty_flag)
 607                         logit("Pseudo-terminal will not be allocated because stdin is not a terminal.");
 608                 tty_flag = 0;
 609         }
 610
 611         /*
 612          * Initialize "log" output.  Since we are the client all output
 613          * actually goes to stderr.
 614          */
 615         log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 616             SYSLOG_FACILITY_USER, 1);
 617
 618         /*
 619          * Read per-user configuration file.  Ignore the system wide config
 620          * file if the user specifies a config file on the command line.
 621          */
 622         if (config != NULL) {
 623                 if (!read_config_file(config, host, &options, 0))
 624                         fatal("Can't open user config file %.100s: "
 625                             "%.100s", config, strerror(errno));
 626         } else {
 627             /*
 628              * Since the config file parsing code aborts if it sees
 629              * options it doesn't recognize, allow users to put
 630              * options specific to compile-time add-ons in alternate
 631              * config files so their primary config file will
 632              * interoperate SSH versions that don't support those
 633              * options.
 634              */
 635 #ifdef GSSAPI
 636                 snprintf(buf, sizeof buf, "%.100s/%.100s.gssapi", pw->pw_dir,
 637                     _PATH_SSH_USER_CONFFILE);
 638                 (void)read_config_file(buf, host, &options, 1);
 639 #ifdef GSI
 640                 snprintf(buf, sizeof buf, "%.100s/%.100s.gsi", pw->pw_dir,
 641                     _PATH_SSH_USER_CONFFILE);
 642                 (void)read_config_file(buf, host, &options, 1);
 643 #endif
 644 #if defined(KRB5)
 645                 snprintf(buf, sizeof buf, "%.100s/%.100s.krb", pw->pw_dir,
 646                     _PATH_SSH_USER_CONFFILE);
 647                 (void)read_config_file(buf, host, &options, 1);
 648 #endif
 649 #endif
 650                 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
 651                     _PATH_SSH_USER_CONFFILE);
 652                 (void)read_config_file(buf, host, &options, 1);
 653
 654                 /* Read systemwide configuration file after use config. */
 655                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host,
 656                     &options, 0);
 657         }
 658
 659         /* Fill configuration defaults. */
 660         fill_default_options(&options);
 661
 662         channel_set_af(options.address_family);
 663
 664         /* reinit */
 665         log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
 666
 667         seed_rng();
 668
 669         if (options.user == NULL) {
 670                 options.user = xstrdup(pw->pw_name);
 671                 options.implicit = 1;
 672         }
 673         else options.implicit = 0;
 674
 675         if (options.hostname != NULL)
 676                 host = options.hostname;
 677
 678         /* force lowercase for hostkey matching */
 679         if (options.host_key_alias != NULL) {
 680                 for (p = options.host_key_alias; *p; p++)
 681                         if (isupper(*p))
 682                                 *p = (char)tolower(*p);
 683         }
 684
 685         /* Get default port if port has not been set. */
 686         if (options.port == 0) {
 687                 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
 688                 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT;
 689         }
 690
 691         if (options.proxy_command != NULL &&
 692             strcmp(options.proxy_command, "none") == 0) {
 693                 xfree(options.proxy_command);
 694                 options.proxy_command = NULL;
 695         }
 696         if (options.control_path != NULL &&
 697             strcmp(options.control_path, "none") == 0) {
 698                 xfree(options.control_path);
 699                 options.control_path = NULL;
 700         }
 701
 702         if (options.control_path != NULL) {
 703                 char thishost[NI_MAXHOST];
 704
 705                 if (gethostname(thishost, sizeof(thishost)) == -1)
 706                         fatal("gethostname: %s", strerror(errno));
 707                 snprintf(buf, sizeof(buf), "%d", options.port);
 708                 cp = tilde_expand_filename(options.control_path,
 709                     original_real_uid);
 710                 xfree(options.control_path);
 711                 options.control_path = percent_expand(cp, "p", buf, "h", host,
 712                     "r", options.user, "l", thishost, (char *)NULL);
 713                 xfree(cp);
 714         }
 715         if (mux_command != 0 && options.control_path == NULL)
 716                 fatal("No ControlPath specified for \"-O\" command");
 717         if (options.control_path != NULL)
 718                 control_client(options.control_path);
 719
 720         timeout_ms = options.connection_timeout * 1000;
 721
 722         /* Open a connection to the remote host. */
 723         if (ssh_connect(host, &hostaddr, options.port,
 724             options.address_family, options.connection_attempts, &timeout_ms,
 725             options.tcp_keep_alive,
 726 #ifdef HAVE_CYGWIN
 727             options.use_privileged_port,
 728 #else
 729             original_effective_uid == 0 && options.use_privileged_port,
 730 #endif
 731             options.proxy_command) != 0)
 732                 exit(255);
 733
 734         if (timeout_ms > 0)
 735                 debug3("timeout: %d ms remain after connect", timeout_ms);
 736
 737         /*
 738          * If we successfully made the connection, load the host private key
 739          * in case we will need it later for combined rsa-rhosts
 740          * authentication. This must be done before releasing extra
 741          * privileges, because the file is only readable by root.
 742          * If we cannot access the private keys, load the public keys
 743          * instead and try to execute the ssh-keysign helper instead.
 744          */
 745         sensitive_data.nkeys = 0;
 746         sensitive_data.keys = NULL;
 747         sensitive_data.external_keysign = 0;
 748         if (options.rhosts_rsa_authentication ||
 749             options.hostbased_authentication) {
 750                 sensitive_data.nkeys = 3;
 751                 sensitive_data.keys = xcalloc(sensitive_data.nkeys,
 752                     sizeof(Key));
 753
 754                 PRIV_START;
 755                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
 756                     _PATH_HOST_KEY_FILE, "", NULL, NULL);
 757                 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
 758                     _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL);
 759                 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
 760                     _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL);
 761                 PRIV_END;
 762
 763                 if (options.hostbased_authentication == 1 &&
 764                     sensitive_data.keys[0] == NULL &&
 765                     sensitive_data.keys[1] == NULL &&
 766                     sensitive_data.keys[2] == NULL) {
 767                         sensitive_data.keys[1] = key_load_public(
 768                             _PATH_HOST_DSA_KEY_FILE, NULL);
 769                         sensitive_data.keys[2] = key_load_public(
 770                             _PATH_HOST_RSA_KEY_FILE, NULL);
 771                         sensitive_data.external_keysign = 1;
 772                 }
 773         }
 774         /*
 775          * Get rid of any extra privileges that we may have.  We will no
 776          * longer need them.  Also, extra privileges could make it very hard
 777          * to read identity files and other non-world-readable files from the
 778          * user's home directory if it happens to be on a NFS volume where
 779          * root is mapped to nobody.
 780          */
 781         if (original_effective_uid == 0) {
 782                 PRIV_START;
 783                 permanently_set_uid(pw);
 784         }
 785
 786         /*
 787          * Now that we are back to our own permissions, create ~/.ssh
 788          * directory if it doesn't already exist.
 789          */
 790         snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
 791         if (stat(buf, &st) < 0)
 792                 if (mkdir(buf, 0700) < 0)
 793                         error("Could not create directory '%.200s'.", buf);
 794
 795         /* load options.identity_files */
 796         load_public_identity_files();
 797
 798         /* Expand ~ in known host file names. */
 799         /* XXX mem-leaks: */
 800         options.system_hostfile =
 801             tilde_expand_filename(options.system_hostfile, original_real_uid);
 802         options.user_hostfile =
 803             tilde_expand_filename(options.user_hostfile, original_real_uid);
 804         options.system_hostfile2 =
 805             tilde_expand_filename(options.system_hostfile2, original_real_uid);
 806         options.user_hostfile2 =
 807             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 808
 809         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 810
 811         /* Log into the remote system.  This never returns if the login fails. */
 812         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
 813             pw, timeout_ms);
 814
 815         /* We no longer need the private host keys.  Clear them now. */
 816         if (sensitive_data.nkeys != 0) {
 817                 for (i = 0; i < sensitive_data.nkeys; i++) {
 818                         if (sensitive_data.keys[i] != NULL) {
 819                                 /* Destroys contents safely */
 820                                 debug3("clear hostkey %d", i);
 821                                 key_free(sensitive_data.keys[i]);
 822                                 sensitive_data.keys[i] = NULL;
 823                         }
 824                 }
 825                 xfree(sensitive_data.keys);
 826         }
 827         for (i = 0; i < options.num_identity_files; i++) {
 828                 if (options.identity_files[i]) {
 829                         xfree(options.identity_files[i]);
 830                         options.identity_files[i] = NULL;
 831                 }
 832                 if (options.identity_keys[i]) {
 833                         key_free(options.identity_keys[i]);
 834                         options.identity_keys[i] = NULL;
 835                 }
 836         }
 837
 838         exit_status = compat20 ? ssh_session2() : ssh_session();
 839         packet_close();
 840
 841         if (options.control_path != NULL && control_fd != -1)
 842                 unlink(options.control_path);
 843
 844         /*
 845          * Send SIGHUP to proxy command if used. We don't wait() in
 846          * case it hangs and instead rely on init to reap the child
 847          */
 848         if (proxy_command_pid > 1)
 849                 kill(proxy_command_pid, SIGHUP);
 850
 851         return exit_status;
 852 }
 853
 854 static void
 855 ssh_init_forwarding(void)
 856 {
 857         int success = 0;
 858         int i;
 859
 860         /* Initiate local TCP/IP port forwardings. */
 861         for (i = 0; i < options.num_local_forwards; i++) {
 862                 debug("Local connections to %.200s:%d forwarded to remote "
 863                     "address %.200s:%d",
 864                     (options.local_forwards[i].listen_host == NULL) ?
 865                     (options.gateway_ports ? "*" : "LOCALHOST") :
 866                     options.local_forwards[i].listen_host,
 867                     options.local_forwards[i].listen_port,
 868                     options.local_forwards[i].connect_host,
 869                     options.local_forwards[i].connect_port);
 870                 success += channel_setup_local_fwd_listener(
 871                     options.local_forwards[i].listen_host,
 872                     options.local_forwards[i].listen_port,
 873                     options.local_forwards[i].connect_host,
 874                     options.local_forwards[i].connect_port,
 875                     options.gateway_ports, options.hpn_disabled,
 876                     options.hpn_buffer_size);
 877         }
 878         if (i > 0 && success != i && options.exit_on_forward_failure)
 879                 fatal("Could not request local forwarding.");
 880         if (i > 0 && success == 0)
 881                 error("Could not request local forwarding.");
 882
 883         /* Initiate remote TCP/IP port forwardings. */
 884         for (i = 0; i < options.num_remote_forwards; i++) {
 885                 debug("Remote connections from %.200s:%d forwarded to "
 886                     "local address %.200s:%d",
 887                     (options.remote_forwards[i].listen_host == NULL) ?
 888                     "LOCALHOST" : options.remote_forwards[i].listen_host,
 889                     options.remote_forwards[i].listen_port,
 890                     options.remote_forwards[i].connect_host,
 891                     options.remote_forwards[i].connect_port);
 892                 if (channel_request_remote_forwarding(
 893                     options.remote_forwards[i].listen_host,
 894                     options.remote_forwards[i].listen_port,
 895                     options.remote_forwards[i].connect_host,
 896                     options.remote_forwards[i].connect_port) < 0) {
 897                         if (options.exit_on_forward_failure)
 898                                 fatal("Could not request remote forwarding.");
 899                         else
 900                                 logit("Warning: Could not request remote "
 901                                     "forwarding.");
 902                 }
 903         }
 904
 905         /* Initiate tunnel forwarding. */
 906         if (options.tun_open != SSH_TUNMODE_NO) {
 907                 if (client_request_tun_fwd(options.tun_open,
 908                     options.tun_local, options.tun_remote) == -1) {
 909                         if (options.exit_on_forward_failure)
 910                                 fatal("Could not request tunnel forwarding.");
 911                         else
 912                                 error("Could not request tunnel forwarding.");
 913                 }
 914         }
 915 }
 916
 917 static void
 918 check_agent_present(void)
 919 {
 920         if (options.forward_agent) {
 921                 /* Clear agent forwarding if we don't have an agent. */
 922                 if (!ssh_agent_present())
 923                         options.forward_agent = 0;
 924         }
 925 }
 926
 927 static int
 928 ssh_session(void)
 929 {
 930         int type;
 931         int interactive = 0;
 932         int have_tty = 0;
 933         struct winsize ws;
 934         char *cp;
 935         const char *display;
 936
 937         /* Enable compression if requested. */
 938         if (options.compression) {
 939                 debug("Requesting compression at level %d.", options.compression_level);
 940
 941                 if (options.compression_level < 1 || options.compression_level > 9)
 942                         fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
 943
 944                 /* Send the request. */
 945                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
 946                 packet_put_int(options.compression_level);
 947                 packet_send();
 948                 packet_write_wait();
 949                 type = packet_read();
 950                 if (type == SSH_SMSG_SUCCESS)
 951                         packet_start_compression(options.compression_level);
 952                 else if (type == SSH_SMSG_FAILURE)
 953                         logit("Warning: Remote host refused compression.");
 954                 else
 955                         packet_disconnect("Protocol error waiting for compression response.");
 956         }
 957         /* Allocate a pseudo tty if appropriate. */
 958         if (tty_flag) {
 959                 debug("Requesting pty.");
 960
 961                 /* Start the packet. */
 962                 packet_start(SSH_CMSG_REQUEST_PTY);
 963
 964                 /* Store TERM in the packet.  There is no limit on the
 965                    length of the string. */
 966                 cp = getenv("TERM");
 967                 if (!cp)
 968                         cp = "";
 969                 packet_put_cstring(cp);
 970
 971                 /* Store window size in the packet. */
 972                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
 973                         memset(&ws, 0, sizeof(ws));
 974                 packet_put_int((u_int)ws.ws_row);
 975                 packet_put_int((u_int)ws.ws_col);
 976                 packet_put_int((u_int)ws.ws_xpixel);
 977                 packet_put_int((u_int)ws.ws_ypixel);
 978
 979                 /* Store tty modes in the packet. */
 980                 tty_make_modes(fileno(stdin), NULL);
 981
 982                 /* Send the packet, and wait for it to leave. */
 983                 packet_send();
 984                 packet_write_wait();
 985
 986                 /* Read response from the server. */
 987                 type = packet_read();
 988                 if (type == SSH_SMSG_SUCCESS) {
 989                         interactive = 1;
 990                         have_tty = 1;
 991                 } else if (type == SSH_SMSG_FAILURE)
 992                         logit("Warning: Remote host failed or refused to allocate a pseudo tty.");
 993                 else
 994                         packet_disconnect("Protocol error waiting for pty request response.");
 995         }
 996         /* Request X11 forwarding if enabled and DISPLAY is set. */
 997         display = getenv("DISPLAY");
 998         if (options.forward_x11 && display != NULL) {
 999                 char *proto, *data;
1000                 /* Get reasonable local authentication information. */
1001                 client_x11_get_proto(display, options.xauth_location,
1002                     options.forward_x11_trusted, &proto, &data);
1003                 /* Request forwarding with authentication spoofing. */
1004                 debug("Requesting X11 forwarding with authentication spoofing.");
1005                 x11_request_forwarding_with_spoofing(0, display, proto, data);
1006
1007                 /* Read response from the server. */
1008                 type = packet_read();
1009                 if (type == SSH_SMSG_SUCCESS) {
1010                         interactive = 1;
1011                 } else if (type == SSH_SMSG_FAILURE) {
1012                         logit("Warning: Remote host denied X11 forwarding.");
1013                 } else {
1014                         packet_disconnect("Protocol error waiting for X11 forwarding");
1015                 }
1016         }
1017         /* Tell the packet module whether this is an interactive session. */
1018         packet_set_interactive(interactive);
1019
1020         /* Request authentication agent forwarding if appropriate. */
1021         check_agent_present();
1022
1023         if (options.forward_agent) {
1024                 debug("Requesting authentication agent forwarding.");
1025                 auth_request_forwarding();
1026
1027                 /* Read response from the server. */
1028                 type = packet_read();
1029                 packet_check_eom();
1030                 if (type != SSH_SMSG_SUCCESS)
1031                         logit("Warning: Remote host denied authentication agent forwarding.");
1032         }
1033
1034         /* Initiate port forwardings. */
1035         ssh_init_forwarding();
1036
1037         /* Execute a local command */
1038         if (options.local_command != NULL &&
1039             options.permit_local_command)
1040                 ssh_local_cmd(options.local_command);
1041
1042         /* If requested, let ssh continue in the background. */
1043         if (fork_after_authentication_flag)
1044                 if (daemon(1, 1) < 0)
1045                         fatal("daemon() failed: %.200s", strerror(errno));
1046
1047         /*
1048          * If a command was specified on the command line, execute the
1049          * command now. Otherwise request the server to start a shell.
1050          */
1051         if (buffer_len(&command) > 0) {
1052                 int len = buffer_len(&command);
1053                 if (len > 900)
1054                         len = 900;
1055                 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
1056                 packet_start(SSH_CMSG_EXEC_CMD);
1057                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1058                 packet_send();
1059                 packet_write_wait();
1060         } else {
1061                 debug("Requesting shell.");
1062                 packet_start(SSH_CMSG_EXEC_SHELL);
1063                 packet_send();
1064                 packet_write_wait();
1065         }
1066
1067         /* Enter the interactive session. */
1068         return client_loop(have_tty, tty_flag ?
1069             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
1070 }
1071
1072 static void
1073 ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt)
1074 {
1075         int id, len;
1076
1077         id = packet_get_int();
1078         len = buffer_len(&command);
1079         if (len > 900)
1080                 len = 900;
1081         packet_check_eom();
1082         if (type == SSH2_MSG_CHANNEL_FAILURE)
1083                 fatal("Request for subsystem '%.*s' failed on channel %d",
1084                     len, (u_char *)buffer_ptr(&command), id);
1085 }
1086
1087 void
1088 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
1089 {
1090         int i;
1091
1092         i = client_global_request_id++;
1093         if (i >= options.num_remote_forwards)
1094                 return;
1095         debug("remote forward %s for: listen %d, connect %s:%d",
1096             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1097             options.remote_forwards[i].listen_port,
1098             options.remote_forwards[i].connect_host,
1099             options.remote_forwards[i].connect_port);
1100         if (type == SSH2_MSG_REQUEST_FAILURE) {
1101                 if (options.exit_on_forward_failure)
1102                         fatal("Error: remote port forwarding failed for "
1103                             "listen port %d",
1104                             options.remote_forwards[i].listen_port);
1105                 else
1106                         logit("Warning: remote port forwarding failed for "
1107                             "listen port %d",
1108                             options.remote_forwards[i].listen_port);
1109         }
1110 }
1111
1112 static void
1113 ssh_control_listener(void)
1114 {
1115         struct sockaddr_un addr;
1116         mode_t old_umask;
1117         int addr_len;
1118
1119         if (options.control_path == NULL ||
1120             options.control_master == SSHCTL_MASTER_NO)
1121                 return;
1122
1123         debug("setting up multiplex master socket");
1124
1125         memset(&addr, '\0', sizeof(addr));
1126         addr.sun_family = AF_UNIX;
1127         addr_len = offsetof(struct sockaddr_un, sun_path) +
1128             strlen(options.control_path) + 1;
1129
1130         if (strlcpy(addr.sun_path, options.control_path,
1131             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1132                 fatal("ControlPath too long");
1133
1134         if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1135                 fatal("%s socket(): %s", __func__, strerror(errno));
1136
1137         old_umask = umask(0177);
1138         if (bind(control_fd, (struct sockaddr *)&addr, addr_len) == -1) {
1139                 control_fd = -1;
1140                 if (errno == EINVAL || errno == EADDRINUSE)
1141                         fatal("ControlSocket %s already exists",
1142                             options.control_path);
1143                 else
1144                         fatal("%s bind(): %s", __func__, strerror(errno));
1145         }
1146         umask(old_umask);
1147
1148         if (listen(control_fd, 64) == -1)
1149                 fatal("%s listen(): %s", __func__, strerror(errno));
1150
1151         set_nonblock(control_fd);
1152 }
1153
1154 /* request pty/x11/agent/tcpfwd/shell for channel */
1155 static void
1156 ssh_session2_setup(int id, void *arg)
1157 {
1158         extern char **environ;
1159         const char *display;
1160         int interactive = tty_flag;
1161
1162         display = getenv("DISPLAY");
1163         if (options.forward_x11 && display != NULL) {
1164                 char *proto, *data;
1165                 /* Get reasonable local authentication information. */
1166                 client_x11_get_proto(display, options.xauth_location,
1167                     options.forward_x11_trusted, &proto, &data);
1168                 /* Request forwarding with authentication spoofing. */
1169                 debug("Requesting X11 forwarding with authentication spoofing.");
1170                 x11_request_forwarding_with_spoofing(id, display, proto, data);
1171                 interactive = 1;
1172                 /* XXX wait for reply */
1173         }
1174
1175         check_agent_present();
1176         if (options.forward_agent) {
1177                 debug("Requesting authentication agent forwarding.");
1178                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1179                 packet_send();
1180         }
1181
1182         client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"),
1183             NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply);
1184
1185         packet_set_interactive(interactive);
1186 }
1187
1188 /* open new channel for a session */
1189 static int
1190 ssh_session2_open(void)
1191 {
1192         Channel *c;
1193         int window, packetmax, in, out, err;
1194         int sock;
1195         int socksize;
1196         int socksizelen = sizeof(int);
1197
1198         if (stdin_null_flag) {
1199                 in = open(_PATH_DEVNULL, O_RDONLY);
1200         } else {
1201                 in = dup(STDIN_FILENO);
1202         }
1203         out = dup(STDOUT_FILENO);
1204         err = dup(STDERR_FILENO);
1205
1206         if (in < 0 || out < 0 || err < 0)
1207                 fatal("dup() in/out/err failed");
1208
1209         /* enable nonblocking unless tty */
1210         if (!isatty(in))
1211                 set_nonblock(in);
1212         if (!isatty(out))
1213                 set_nonblock(out);
1214         if (!isatty(err))
1215                 set_nonblock(err);
1216
1217         /* we need to check to see if what they want to do about buffer */
1218         /* sizes here. In a hpn to nonhpn connection we want to limit */
1219         /* the window size to something reasonable in case the far side */
1220         /* has the large window bug. In hpn to hpn connection we want to */
1221         /* use the max window size but allow the user to override it */
1222         /* lastly if they disabled hpn then use the ssh std window size */
1223
1224         /* so why don't we just do a getsockopt() here and set the */
1225         /* ssh window to that? In the case of a autotuning receive */
1226         /* window the window would get stuck at the initial buffer */
1227         /* size generally less than 96k. Therefore we need to set the */
1228         /* maximum ssh window size to the maximum hpn buffer size */
1229         /* unless the user has specifically set the tcprcvbufpoll */
1230         /* to no. In which case we *can* just set the window to the */
1231         /* minimum of the hpn buffer size and tcp receive buffer size */
1232
1233         if(options.hpn_disabled)
1234         {
1235                 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT;
1236         }
1237         else if (datafellows & SSH_BUG_LARGEWINDOW)
1238         {
1239                 debug("HPN to Non-HPN Connection");
1240                 if (options.hpn_buffer_size < 0)
1241                         options.hpn_buffer_size = 2*1024*1024;
1242         }
1243         else
1244         {
1245                 if (options.hpn_buffer_size < 0)
1246                         options.hpn_buffer_size = BUFFER_MAX_LEN_HPN;
1247
1248                 /*create a socket but don't connect it */
1249                 /* we use that the get the rcv socket size */
1250                 sock = socket(AF_INET, SOCK_STREAM, 0);
1251                 /* if they are using the tcp_rcv_buf option */
1252                 /* attempt to set the buffer size to that */
1253                 if (options.tcp_rcv_buf)
1254                         setsockopt(sock, SOL_SOCKET, SO_RCVBUF, (void *)&options.tcp_rcv_buf,
1255                                    sizeof(options.tcp_rcv_buf));
1256                 getsockopt(sock, SOL_SOCKET, SO_RCVBUF,
1257                            &socksize, &socksizelen);
1258                 close(sock);
1259                 debug("socksize %d", socksize);
1260                 if (options.tcp_rcv_buf_poll <= 0)
1261                 {
1262                         options.hpn_buffer_size = MIN(socksize,options.hpn_buffer_size);
1263                         debug ("MIN of TCP RWIN and HPNBufferSize: %d", options.hpn_buffer_size);
1264                 }
1265                 else
1266                 {
1267                         if (options.tcp_rcv_buf > 0)
1268                                 options.hpn_buffer_size = MIN(options.tcp_rcv_buf, options.hpn_buffer_size);
1269                                 debug ("MIN of TCPRcvBuf and HPNBufferSize: %d", options.hpn_buffer_size);
1270                 }
1271
1272         }
1273
1274         debug("Final hpn_buffer_size = %d", options.hpn_buffer_size);
1275
1276         window = options.hpn_buffer_size;
1277
1278         packetmax = CHAN_SES_PACKET_DEFAULT;
1279         if (tty_flag) {
1280                 window = 4*CHAN_SES_PACKET_DEFAULT;
1281                 window >>= 1;
1282                 packetmax >>= 1;
1283         }
1284         c = channel_new(
1285             "session", SSH_CHANNEL_OPENING, in, out, err,
1286             window, packetmax, CHAN_EXTENDED_WRITE,
1287             "client-session", /*nonblock*/0);
1288
1289         if ((options.tcp_rcv_buf_poll > 0) && (!options.hpn_disabled)) {
1290                 c->dynamic_window = 1;
1291                 debug ("Enabled Dynamic Window Scaling\n");
1292         }
1293         debug3("ssh_session2_open: channel_new: %d", c->self);
1294
1295         channel_send_open(c->self);
1296         if (!no_shell_flag)
1297                 channel_register_confirm(c->self, ssh_session2_setup, NULL);
1298
1299         return c->self;
1300 }
1301
1302 static int
1303 ssh_session2(void)
1304 {
1305         int id = -1;
1306
1307         /* XXX should be pre-session */
1308         ssh_init_forwarding();
1309
1310         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1311                 id = ssh_session2_open();
1312
1313         /* Execute a local command */
1314         if (options.local_command != NULL &&
1315             options.permit_local_command)
1316                 ssh_local_cmd(options.local_command);
1317
1318         /* Start listening for multiplex clients */
1319         ssh_control_listener();
1320
1321         /* If requested, let ssh continue in the background. */
1322         if (fork_after_authentication_flag)
1323                 if (daemon(1, 1) < 0)
1324                         fatal("daemon() failed: %.200s", strerror(errno));
1325
1326         return client_loop(tty_flag, tty_flag ?
1327             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1328 }
1329
1330 static void
1331 load_public_identity_files(void)
1332 {
1333         char *filename, *cp, thishost[NI_MAXHOST];
1334         char *pwdir = NULL, *pwname = NULL;
1335         int i = 0;
1336         Key *public;
1337         struct passwd *pw;
1338 #ifdef SMARTCARD
1339         Key **keys;
1340
1341         if (options.smartcard_device != NULL &&
1342             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1343             (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) {
1344                 int count = 0;
1345                 for (i = 0; keys[i] != NULL; i++) {
1346                         count++;
1347                         memmove(&options.identity_files[1], &options.identity_files[0],
1348                             sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1349                         memmove(&options.identity_keys[1], &options.identity_keys[0],
1350                             sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1351                         options.num_identity_files++;
1352                         options.identity_keys[0] = keys[i];
1353                         options.identity_files[0] = sc_get_key_label(keys[i]);
1354                 }
1355                 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1356                         options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1357                 i = count;
1358                 xfree(keys);
1359         }
1360 #endif /* SMARTCARD */
1361         if ((pw = getpwuid(original_real_uid)) == NULL)
1362                 fatal("load_public_identity_files: getpwuid failed");
1363         pwname = xstrdup(pw->pw_name);
1364         pwdir = xstrdup(pw->pw_dir);
1365         if (gethostname(thishost, sizeof(thishost)) == -1)
1366                 fatal("load_public_identity_files: gethostname: %s",
1367                     strerror(errno));
1368         for (; i < options.num_identity_files; i++) {
1369                 cp = tilde_expand_filename(options.identity_files[i],
1370                     original_real_uid);
1371                 filename = percent_expand(cp, "d", pwdir,
1372                     "u", pwname, "l", thishost, "h", host,
1373                     "r", options.user, (char *)NULL);
1374                 xfree(cp);
1375                 public = key_load_public(filename, NULL);
1376                 debug("identity file %s type %d", filename,
1377                     public ? public->type : -1);
1378                 xfree(options.identity_files[i]);
1379                 options.identity_files[i] = filename;
1380                 options.identity_keys[i] = public;
1381         }
1382         bzero(pwname, strlen(pwname));
1383         xfree(pwname);
1384         bzero(pwdir, strlen(pwdir));
1385         xfree(pwdir);
1386 }
1387
1388 static void
1389 control_client_sighandler(int signo)
1390 {
1391         control_client_terminate = signo;
1392 }
1393
1394 static void
1395 control_client_sigrelay(int signo)
1396 {
1397         int save_errno = errno;
1398
1399         if (control_server_pid > 1)
1400                 kill(control_server_pid, signo);
1401
1402         errno = save_errno;
1403 }
1404
1405 static int
1406 env_permitted(char *env)
1407 {
1408         int i, ret;
1409         char name[1024], *cp;
1410
1411         if ((cp = strchr(env, '=')) == NULL || cp == env)
1412                 return (0);
1413         ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
1414         if (ret <= 0 || (size_t)ret >= sizeof(name))
1415                 fatal("env_permitted: name '%.100s...' too long", env);
1416
1417         for (i = 0; i < options.num_send_env; i++)
1418                 if (match_pattern(name, options.send_env[i]))
1419                         return (1);
1420
1421         return (0);
1422 }
1423
1424 static void
1425 control_client(const char *path)
1426 {
1427         struct sockaddr_un addr;
1428         int i, r, fd, sock, exitval[2], num_env, addr_len;
1429         Buffer m;
1430         char *term;
1431         extern char **environ;
1432         u_int  flags;
1433
1434         if (mux_command == 0)
1435                 mux_command = SSHMUX_COMMAND_OPEN;
1436
1437         switch (options.control_master) {
1438         case SSHCTL_MASTER_AUTO:
1439         case SSHCTL_MASTER_AUTO_ASK:
1440                 debug("auto-mux: Trying existing master");
1441                 /* FALLTHROUGH */
1442         case SSHCTL_MASTER_NO:
1443                 break;
1444         default:
1445                 return;
1446         }
1447
1448         memset(&addr, '\0', sizeof(addr));
1449         addr.sun_family = AF_UNIX;
1450         addr_len = offsetof(struct sockaddr_un, sun_path) +
1451             strlen(path) + 1;
1452
1453         if (strlcpy(addr.sun_path, path,
1454             sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
1455                 fatal("ControlPath too long");
1456
1457         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1458                 fatal("%s socket(): %s", __func__, strerror(errno));
1459
1460         if (connect(sock, (struct sockaddr *)&addr, addr_len) == -1) {
1461                 if (mux_command != SSHMUX_COMMAND_OPEN) {
1462                         fatal("Control socket connect(%.100s): %s", path,
1463                             strerror(errno));
1464                 }
1465                 if (errno == ENOENT)
1466                         debug("Control socket \"%.100s\" does not exist", path);
1467                 else {
1468                         error("Control socket connect(%.100s): %s", path,
1469                             strerror(errno));
1470                 }
1471                 close(sock);
1472                 return;
1473         }
1474
1475         if (stdin_null_flag) {
1476                 if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1477                         fatal("open(/dev/null): %s", strerror(errno));
1478                 if (dup2(fd, STDIN_FILENO) == -1)
1479                         fatal("dup2: %s", strerror(errno));
1480                 if (fd > STDERR_FILENO)
1481                         close(fd);
1482         }
1483
1484         term = getenv("TERM");
1485
1486         flags = 0;
1487         if (tty_flag)
1488                 flags |= SSHMUX_FLAG_TTY;
1489         if (subsystem_flag)
1490                 flags |= SSHMUX_FLAG_SUBSYS;
1491         if (options.forward_x11)
1492                 flags |= SSHMUX_FLAG_X11_FWD;
1493         if (options.forward_agent)
1494                 flags |= SSHMUX_FLAG_AGENT_FWD;
1495
1496         signal(SIGPIPE, SIG_IGN);
1497
1498         buffer_init(&m);
1499
1500         /* Send our command to server */
1501         buffer_put_int(&m, mux_command);
1502         buffer_put_int(&m, flags);
1503         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1504                 fatal("%s: msg_send", __func__);
1505         buffer_clear(&m);
1506
1507         /* Get authorisation status and PID of controlee */
1508         if (ssh_msg_recv(sock, &m) == -1)
1509                 fatal("%s: msg_recv", __func__);
1510         if (buffer_get_char(&m) != SSHMUX_VER)
1511                 fatal("%s: wrong version", __func__);
1512         if (buffer_get_int(&m) != 1)
1513                 fatal("Connection to master denied");
1514         control_server_pid = buffer_get_int(&m);
1515
1516         buffer_clear(&m);
1517
1518         switch (mux_command) {
1519         case SSHMUX_COMMAND_ALIVE_CHECK:
1520                 fprintf(stderr, "Master running (pid=%d)\r\n",
1521                     control_server_pid);
1522                 exit(0);
1523         case SSHMUX_COMMAND_TERMINATE:
1524                 fprintf(stderr, "Exit request sent.\r\n");
1525                 exit(0);
1526         case SSHMUX_COMMAND_OPEN:
1527                 /* continue below */
1528                 break;
1529         default:
1530                 fatal("silly mux_command %d", mux_command);
1531         }
1532
1533         /* SSHMUX_COMMAND_OPEN */
1534         buffer_put_cstring(&m, term ? term : "");
1535         buffer_append(&command, "\0", 1);
1536         buffer_put_cstring(&m, buffer_ptr(&command));
1537
1538         if (options.num_send_env == 0 || environ == NULL) {
1539                 buffer_put_int(&m, 0);
1540         } else {
1541                 /* Pass environment */
1542                 num_env = 0;
1543                 for (i = 0; environ[i] != NULL; i++)
1544                         if (env_permitted(environ[i]))
1545                                 num_env++; /* Count */
1546
1547                 buffer_put_int(&m, num_env);
1548
1549                 for (i = 0; environ[i] != NULL && num_env >= 0; i++)
1550                         if (env_permitted(environ[i])) {
1551                                 num_env--;
1552                                 buffer_put_cstring(&m, environ[i]);
1553                         }
1554         }
1555
1556         if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1)
1557                 fatal("%s: msg_send", __func__);
1558
1559         if (mm_send_fd(sock, STDIN_FILENO) == -1 ||
1560             mm_send_fd(sock, STDOUT_FILENO) == -1 ||
1561             mm_send_fd(sock, STDERR_FILENO) == -1)
1562                 fatal("%s: send fds failed", __func__);
1563
1564         /* Wait for reply, so master has a chance to gather ttymodes */
1565         buffer_clear(&m);
1566         if (ssh_msg_recv(sock, &m) == -1)
1567                 fatal("%s: msg_recv", __func__);
1568         if (buffer_get_char(&m) != SSHMUX_VER)
1569                 fatal("%s: wrong version", __func__);
1570         buffer_free(&m);
1571
1572         signal(SIGHUP, control_client_sighandler);
1573         signal(SIGINT, control_client_sighandler);
1574         signal(SIGTERM, control_client_sighandler);
1575         signal(SIGWINCH, control_client_sigrelay);
1576
1577         if (tty_flag)
1578                 enter_raw_mode();
1579
1580         /*
1581          * Stick around until the controlee closes the client_fd.
1582          * Before it does, it is expected to write this process' exit
1583          * value (one int). This process must read the value and wait for
1584          * the closure of the client_fd; if this one closes early, the
1585          * multiplex master will terminate early too (possibly losing data).
1586          */
1587         exitval[0] = 0;
1588         for (i = 0; !control_client_terminate && i < (int)sizeof(exitval);) {
1589                 r = read(sock, (char *)exitval + i, sizeof(exitval) - i);
1590                 if (r == 0) {
1591                         debug2("Received EOF from master");
1592                         break;
1593                 }
1594                 if (r == -1) {
1595                         if (errno == EINTR)
1596                                 continue;
1597                         fatal("%s: read %s", __func__, strerror(errno));
1598                 }
1599                 i += r;
1600         }
1601
1602         close(sock);
1603         leave_raw_mode();
1604         if (i > (int)sizeof(int))
1605                 fatal("%s: master returned too much data (%d > %lu)",
1606                     __func__, i, sizeof(int));
1607         if (control_client_terminate) {
1608                 debug2("Exiting on signal %d", control_client_terminate);
1609                 exitval[0] = 255;
1610         } else if (i < (int)sizeof(int)) {
1611                 debug2("Control master terminated unexpectedly");
1612                 exitval[0] = 255;
1613         } else
1614                 debug2("Received exit status from master %d", exitval[0]);
1615
1616         if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1617                 fprintf(stderr, "Shared connection to %s closed.\r\n", host);
1618
1619         exit(exitval[0]);
1620 }