openssh/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 1.209 2004/03/11 10:21:17 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 "channels.h"
  57 #include "key.h"
  58 #include "authfd.h"
  59 #include "authfile.h"
  60 #include "pathnames.h"
  61 #include "clientloop.h"
  62 #include "log.h"
  63 #include "readconf.h"
  64 #include "sshconnect.h"
  65 #include "tildexpand.h"
  66 #include "dispatch.h"
  67 #include "misc.h"
  68 #include "kex.h"
  69 #include "mac.h"
  70 #include "sshtty.h"
  71
  72 #ifdef SMARTCARD
  73 #include "scard.h"
  74 #endif
  75
  76 #ifdef HAVE___PROGNAME
  77 extern char *__progname;
  78 #else
  79 char *__progname;
  80 #endif
  81
  82 /* Flag indicating whether debug mode is on.  This can be set on the command line. */
  83 int debug_flag = 0;
  84
  85 /* Flag indicating whether a tty should be allocated */
  86 int tty_flag = 0;
  87 int no_tty_flag = 0;
  88 int force_tty_flag = 0;
  89
  90 /* don't exec a shell */
  91 int no_shell_flag = 0;
  92
  93 /*
  94  * Flag indicating that nothing should be read from stdin.  This can be set
  95  * on the command line.
  96  */
  97 int stdin_null_flag = 0;
  98
  99 /*
 100  * Flag indicating that ssh should fork after authentication.  This is useful
 101  * so that the passphrase can be entered manually, and then ssh goes to the
 102  * background.
 103  */
 104 int fork_after_authentication_flag = 0;
 105
 106 /*
 107  * General data structure for command line options and options configurable
 108  * in configuration files.  See readconf.h.
 109  */
 110 Options options;
 111
 112 /* optional user configfile */
 113 char *config = NULL;
 114
 115 /*
 116  * Name of the host we are connecting to.  This is the name given on the
 117  * command line, or the HostName specified for the user-supplied name in a
 118  * configuration file.
 119  */
 120 char *host;
 121
 122 /* socket address the host resolves to */
 123 struct sockaddr_storage hostaddr;
 124
 125 /* Private host keys. */
 126 Sensitive sensitive_data;
 127
 128 /* Original real UID. */
 129 uid_t original_real_uid;
 130 uid_t original_effective_uid;
 131
 132 /* command to be executed */
 133 Buffer command;
 134
 135 /* Should we execute a command or invoke a subsystem? */
 136 int subsystem_flag = 0;
 137
 138 /* # of replies received for global requests */
 139 static int client_global_request_id = 0;
 140
 141 /* pid of proxycommand child process */
 142 pid_t proxy_command_pid = 0;
 143
 144 /* Prints a help message to the user.  This function never returns. */
 145
 146 static void
 147 usage(void)
 148 {
 149         fprintf(stderr,
 150 "usage: ssh [-1246AaCfghkNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n"
 151 "           [-D port] [-e escape_char] [-F configfile] [-i identity_file]\n"
 152 "           [-L port:host:hostport] [-l login_name] [-m mac_spec] [-o option]\n"
 153 "           [-p port] [-R port:host:hostport] [user@]hostname [command]\n"
 154         );
 155         exit(1);
 156 }
 157
 158 static int ssh_session(void);
 159 static int ssh_session2(void);
 160 static void load_public_identity_files(void);
 161
 162 /*
 163  * Main program for the ssh client.
 164  */
 165 int
 166 main(int ac, char **av)
 167 {
 168         int i, opt, exit_status;
 169         u_short fwd_port, fwd_host_port;
 170         char sfwd_port[6], sfwd_host_port[6];
 171         char *p, *cp, *line, buf[256];
 172         struct stat st;
 173         struct passwd *pw;
 174         int dummy;
 175         extern int optind, optreset;
 176         extern char *optarg;
 177
 178         __progname = ssh_get_progname(av[0]);
 179         init_rng();
 180
 181         /*
 182          * Save the original real uid.  It will be needed later (uid-swapping
 183          * may clobber the real uid).
 184          */
 185         original_real_uid = getuid();
 186         original_effective_uid = geteuid();
 187
 188         /*
 189          * Use uid-swapping to give up root privileges for the duration of
 190          * option processing.  We will re-instantiate the rights when we are
 191          * ready to create the privileged port, and will permanently drop
 192          * them when the port has been created (actually, when the connection
 193          * has been made, as we may need to create the port several times).
 194          */
 195         PRIV_END;
 196
 197 #ifdef HAVE_SETRLIMIT
 198         /* If we are installed setuid root be careful to not drop core. */
 199         if (original_real_uid != original_effective_uid) {
 200                 struct rlimit rlim;
 201                 rlim.rlim_cur = rlim.rlim_max = 0;
 202                 if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 203                         fatal("setrlimit failed: %.100s", strerror(errno));
 204         }
 205 #endif
 206         /* Get user data. */
 207         pw = getpwuid(original_real_uid);
 208         if (!pw) {
 209                 logit("You don't exist, go away!");
 210                 exit(1);
 211         }
 212         /* Take a copy of the returned structure. */
 213         pw = pwcopy(pw);
 214
 215         /*
 216          * Set our umask to something reasonable, as some files are created
 217          * with the default umask.  This will make them world-readable but
 218          * writable only by the owner, which is ok for all files for which we
 219          * don't set the modes explicitly.
 220          */
 221         umask(022);
 222
 223         /* Initialize option structure to indicate that no values have been set. */
 224         initialize_options(&options);
 225
 226         /* Parse command-line arguments. */
 227         host = NULL;
 228
 229 again:
 230         while ((opt = getopt(ac, av,
 231             "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:NPR:TVXY")) != -1) {
 232                 switch (opt) {
 233                 case '1':
 234                         options.protocol = SSH_PROTO_1;
 235                         break;
 236                 case '2':
 237                         options.protocol = SSH_PROTO_2;
 238                         break;
 239                 case '4':
 240                         options.address_family = AF_INET;
 241                         break;
 242                 case '6':
 243                         options.address_family = AF_INET6;
 244                         break;
 245                 case 'n':
 246                         stdin_null_flag = 1;
 247                         break;
 248                 case 'f':
 249                         fork_after_authentication_flag = 1;
 250                         stdin_null_flag = 1;
 251                         break;
 252                 case 'x':
 253                         options.forward_x11 = 0;
 254                         break;
 255                 case 'X':
 256                         options.forward_x11 = 1;
 257                         break;
 258                 case 'Y':
 259                         options.forward_x11 = 1;
 260                         options.forward_x11_trusted = 1;
 261                         break;
 262                 case 'g':
 263                         options.gateway_ports = 1;
 264                         break;
 265                 case 'P':       /* deprecated */
 266                         options.use_privileged_port = 0;
 267                         break;
 268                 case 'a':
 269                         options.forward_agent = 0;
 270                         break;
 271                 case 'A':
 272                         options.forward_agent = 1;
 273                         break;
 274                 case 'k':
 275                         options.gss_deleg_creds = 0;
 276                         break;
 277                 case 'i':
 278                         if (stat(optarg, &st) < 0) {
 279                                 fprintf(stderr, "Warning: Identity file %s "
 280                                     "does not exist.\n", optarg);
 281                                 break;
 282                         }
 283                         if (options.num_identity_files >=
 284                             SSH_MAX_IDENTITY_FILES)
 285                                 fatal("Too many identity files specified "
 286                                     "(max %d)", SSH_MAX_IDENTITY_FILES);
 287                         options.identity_files[options.num_identity_files++] =
 288                             xstrdup(optarg);
 289                         break;
 290                 case 'I':
 291 #ifdef SMARTCARD
 292                         options.smartcard_device = xstrdup(optarg);
 293 #else
 294                         fprintf(stderr, "no support for smartcards.\n");
 295 #endif
 296                         break;
 297                 case 't':
 298                         if (tty_flag)
 299                                 force_tty_flag = 1;
 300                         tty_flag = 1;
 301                         break;
 302                 case 'v':
 303                         if (debug_flag == 0) {
 304                                 debug_flag = 1;
 305                                 options.log_level = SYSLOG_LEVEL_DEBUG1;
 306                         } else {
 307                                 if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 308                                         options.log_level++;
 309                                 break;
 310                         }
 311                         /* fallthrough */
 312                 case 'V':
 313                         fprintf(stderr, "%s, %s\n",
 314                             SSH_VERSION, SSLeay_version(SSLEAY_VERSION));
 315                         if (opt == 'V')
 316                                 exit(0);
 317                         break;
 318                 case 'q':
 319                         options.log_level = SYSLOG_LEVEL_QUIET;
 320                         break;
 321                 case 'e':
 322                         if (optarg[0] == '^' && optarg[2] == 0 &&
 323                             (u_char) optarg[1] >= 64 &&
 324                             (u_char) optarg[1] < 128)
 325                                 options.escape_char = (u_char) optarg[1] & 31;
 326                         else if (strlen(optarg) == 1)
 327                                 options.escape_char = (u_char) optarg[0];
 328                         else if (strcmp(optarg, "none") == 0)
 329                                 options.escape_char = SSH_ESCAPECHAR_NONE;
 330                         else {
 331                                 fprintf(stderr, "Bad escape character '%s'.\n",
 332                                     optarg);
 333                                 exit(1);
 334                         }
 335                         break;
 336                 case 'c':
 337                         if (ciphers_valid(optarg)) {
 338                                 /* SSH2 only */
 339                                 options.ciphers = xstrdup(optarg);
 340                                 options.cipher = SSH_CIPHER_ILLEGAL;
 341                         } else {
 342                                 /* SSH1 only */
 343                                 options.cipher = cipher_number(optarg);
 344                                 if (options.cipher == -1) {
 345                                         fprintf(stderr,
 346                                             "Unknown cipher type '%s'\n",
 347                                             optarg);
 348                                         exit(1);
 349                                 }
 350                                 if (options.cipher == SSH_CIPHER_3DES)
 351                                         options.ciphers = "3des-cbc";
 352                                 else if (options.cipher == SSH_CIPHER_BLOWFISH)
 353                                         options.ciphers = "blowfish-cbc";
 354                                 else
 355                                         options.ciphers = (char *)-1;
 356                         }
 357                         break;
 358                 case 'm':
 359                         if (mac_valid(optarg))
 360                                 options.macs = xstrdup(optarg);
 361                         else {
 362                                 fprintf(stderr, "Unknown mac type '%s'\n",
 363                                     optarg);
 364                                 exit(1);
 365                         }
 366                         break;
 367                 case 'p':
 368                         options.port = a2port(optarg);
 369                         if (options.port == 0) {
 370                                 fprintf(stderr, "Bad port '%s'\n", optarg);
 371                                 exit(1);
 372                         }
 373                         break;
 374                 case 'l':
 375                         options.user = optarg;
 376                         break;
 377
 378                 case 'L':
 379                 case 'R':
 380                         if (sscanf(optarg, "%5[0123456789]:%255[^:]:%5[0123456789]",
 381                             sfwd_port, buf, sfwd_host_port) != 3 &&
 382                             sscanf(optarg, "%5[0123456789]/%255[^/]/%5[0123456789]",
 383                             sfwd_port, buf, sfwd_host_port) != 3) {
 384                                 fprintf(stderr,
 385                                     "Bad forwarding specification '%s'\n",
 386                                     optarg);
 387                                 usage();
 388                                 /* NOTREACHED */
 389                         }
 390                         if ((fwd_port = a2port(sfwd_port)) == 0 ||
 391                             (fwd_host_port = a2port(sfwd_host_port)) == 0) {
 392                                 fprintf(stderr,
 393                                     "Bad forwarding port(s) '%s'\n", optarg);
 394                                 exit(1);
 395                         }
 396                         if (opt == 'L')
 397                                 add_local_forward(&options, fwd_port, buf,
 398                                     fwd_host_port);
 399                         else if (opt == 'R')
 400                                 add_remote_forward(&options, fwd_port, buf,
 401                                     fwd_host_port);
 402                         break;
 403
 404                 case 'D':
 405                         fwd_port = a2port(optarg);
 406                         if (fwd_port == 0) {
 407                                 fprintf(stderr, "Bad dynamic port '%s'\n",
 408                                     optarg);
 409                                 exit(1);
 410                         }
 411                         add_local_forward(&options, fwd_port, "socks", 0);
 412                         break;
 413
 414                 case 'C':
 415                         options.compression = 1;
 416                         break;
 417                 case 'N':
 418                         no_shell_flag = 1;
 419                         no_tty_flag = 1;
 420                         break;
 421                 case 'T':
 422                         no_tty_flag = 1;
 423                         break;
 424                 case 'o':
 425                         dummy = 1;
 426                         line = xstrdup(optarg);
 427                         if (process_config_line(&options, host ? host : "",
 428                             line, "command-line", 0, &dummy) != 0)
 429                                 exit(1);
 430                         xfree(line);
 431                         break;
 432                 case 's':
 433                         subsystem_flag = 1;
 434                         break;
 435                 case 'b':
 436                         options.bind_address = optarg;
 437                         break;
 438                 case 'F':
 439                         config = optarg;
 440                         break;
 441                 default:
 442                         usage();
 443                 }
 444         }
 445
 446         ac -= optind;
 447         av += optind;
 448
 449         if (ac > 0 && !host && **av != '-') {
 450                 if (strrchr(*av, '@')) {
 451                         p = xstrdup(*av);
 452                         cp = strrchr(p, '@');
 453                         if (cp == NULL || cp == p)
 454                                 usage();
 455                         options.user = p;
 456                         *cp = '\0';
 457                         host = ++cp;
 458                 } else
 459                         host = *av;
 460                 if (ac > 1) {
 461                         optind = optreset = 1;
 462                         goto again;
 463                 }
 464                 ac--, av++;
 465         }
 466
 467         /* Check that we got a host name. */
 468         if (!host)
 469                 usage();
 470
 471         SSLeay_add_all_algorithms();
 472         ERR_load_crypto_strings();
 473
 474         /* Initialize the command to execute on remote host. */
 475         buffer_init(&command);
 476
 477         /*
 478          * Save the command to execute on the remote host in a buffer. There
 479          * is no limit on the length of the command, except by the maximum
 480          * packet size.  Also sets the tty flag if there is no command.
 481          */
 482         if (!ac) {
 483                 /* No command specified - execute shell on a tty. */
 484                 tty_flag = 1;
 485                 if (subsystem_flag) {
 486                         fprintf(stderr,
 487                             "You must specify a subsystem to invoke.\n");
 488                         usage();
 489                 }
 490         } else {
 491                 /* A command has been specified.  Store it into the buffer. */
 492                 for (i = 0; i < ac; i++) {
 493                         if (i)
 494                                 buffer_append(&command, " ", 1);
 495                         buffer_append(&command, av[i], strlen(av[i]));
 496                 }
 497         }
 498
 499         /* Cannot fork to background if no command. */
 500         if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag)
 501                 fatal("Cannot fork into background without a command to execute.");
 502
 503         /* Allocate a tty by default if no command specified. */
 504         if (buffer_len(&command) == 0)
 505                 tty_flag = 1;
 506
 507         /* Force no tty */
 508         if (no_tty_flag)
 509                 tty_flag = 0;
 510         /* Do not allocate a tty if stdin is not a tty. */
 511         if (!isatty(fileno(stdin)) && !force_tty_flag) {
 512                 if (tty_flag)
 513                         logit("Pseudo-terminal will not be allocated because stdin is not a terminal.");
 514                 tty_flag = 0;
 515         }
 516
 517         /*
 518          * Initialize "log" output.  Since we are the client all output
 519          * actually goes to stderr.
 520          */
 521         log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
 522             SYSLOG_FACILITY_USER, 1);
 523
 524         /*
 525          * Read per-user configuration file.  Ignore the system wide config
 526          * file if the user specifies a config file on the command line.
 527          */
 528         if (config != NULL) {
 529                 if (!read_config_file(config, host, &options))
 530                         fatal("Can't open user config file %.100s: "
 531                             "%.100s", config, strerror(errno));
 532         } else  {
 533             /*
 534              * Since the config file parsing code aborts if it sees
 535              * options it doesn't recognize, allow users to put
 536              * options specific to compile-time add-ons in alternate
 537              * config files so their primary config file will
 538              * interoperate SSH versions that don't support those
 539              * options.
 540              */
 541 #ifdef GSSAPI
 542                 snprintf(buf, sizeof buf, "%.100s/%.100s.gssapi", pw->pw_dir,
 543                     _PATH_SSH_USER_CONFFILE);
 544                 (void)read_config_file(buf, host, &options);
 545 #ifdef GSI
 546                 snprintf(buf, sizeof buf, "%.100s/%.100s.gsi", pw->pw_dir,
 547                     _PATH_SSH_USER_CONFFILE);
 548                 (void)read_config_file(buf, host, &options);
 549 #endif
 550 #if defined(KRB5)
 551                 snprintf(buf, sizeof buf, "%.100s/%.100s.krb", pw->pw_dir,
 552                     _PATH_SSH_USER_CONFFILE);
 553                 (void)read_config_file(buf, host, &options);
 554 #endif
 555 #endif
 556                 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir,
 557                     _PATH_SSH_USER_CONFFILE);
 558                 (void)read_config_file(buf, host, &options);
 559
 560                 /* Read systemwide configuration file after use config. */
 561                 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, &options);
 562         }
 563
 564         /* Fill configuration defaults. */
 565         fill_default_options(&options);
 566
 567         channel_set_af(options.address_family);
 568
 569         /* reinit */
 570         log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1);
 571
 572         seed_rng();
 573
 574         if (options.user == NULL) {
 575                 options.user = xstrdup(pw->pw_name);
 576                 options.implicit = 1;
 577         }
 578         else options.implicit = 0;
 579
 580         if (options.hostname != NULL)
 581                 host = options.hostname;
 582
 583         /* force lowercase for hostkey matching */
 584         if (options.host_key_alias != NULL) {
 585                 for (p = options.host_key_alias; *p; p++)
 586                         if (isupper(*p))
 587                                 *p = tolower(*p);
 588         }
 589
 590         if (options.proxy_command != NULL &&
 591             strcmp(options.proxy_command, "none") == 0)
 592                 options.proxy_command = NULL;
 593
 594         /* Open a connection to the remote host. */
 595         if (ssh_connect(host, &hostaddr, options.port,
 596             options.address_family, options.connection_attempts,
 597 #ifdef HAVE_CYGWIN
 598             options.use_privileged_port,
 599 #else
 600             original_effective_uid == 0 && options.use_privileged_port,
 601 #endif
 602             options.proxy_command) != 0)
 603                 exit(1);
 604
 605         /*
 606          * If we successfully made the connection, load the host private key
 607          * in case we will need it later for combined rsa-rhosts
 608          * authentication. This must be done before releasing extra
 609          * privileges, because the file is only readable by root.
 610          * If we cannot access the private keys, load the public keys
 611          * instead and try to execute the ssh-keysign helper instead.
 612          */
 613         sensitive_data.nkeys = 0;
 614         sensitive_data.keys = NULL;
 615         sensitive_data.external_keysign = 0;
 616         if (options.rhosts_rsa_authentication ||
 617             options.hostbased_authentication) {
 618                 sensitive_data.nkeys = 3;
 619                 sensitive_data.keys = xmalloc(sensitive_data.nkeys *
 620                     sizeof(Key));
 621
 622                 PRIV_START;
 623                 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
 624                     _PATH_HOST_KEY_FILE, "", NULL);
 625                 sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
 626                     _PATH_HOST_DSA_KEY_FILE, "", NULL);
 627                 sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
 628                     _PATH_HOST_RSA_KEY_FILE, "", NULL);
 629                 PRIV_END;
 630
 631                 if (options.hostbased_authentication == 1 &&
 632                     sensitive_data.keys[0] == NULL &&
 633                     sensitive_data.keys[1] == NULL &&
 634                     sensitive_data.keys[2] == NULL) {
 635                         sensitive_data.keys[1] = key_load_public(
 636                             _PATH_HOST_DSA_KEY_FILE, NULL);
 637                         sensitive_data.keys[2] = key_load_public(
 638                             _PATH_HOST_RSA_KEY_FILE, NULL);
 639                         sensitive_data.external_keysign = 1;
 640                 }
 641         }
 642         /*
 643          * Get rid of any extra privileges that we may have.  We will no
 644          * longer need them.  Also, extra privileges could make it very hard
 645          * to read identity files and other non-world-readable files from the
 646          * user's home directory if it happens to be on a NFS volume where
 647          * root is mapped to nobody.
 648          */
 649         seteuid(original_real_uid);
 650         setuid(original_real_uid);
 651
 652         /*
 653          * Now that we are back to our own permissions, create ~/.ssh
 654          * directory if it doesn\'t already exist.
 655          */
 656         snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR);
 657         if (stat(buf, &st) < 0)
 658                 if (mkdir(buf, 0700) < 0)
 659                         error("Could not create directory '%.200s'.", buf);
 660
 661         /* load options.identity_files */
 662         load_public_identity_files();
 663
 664         /* Expand ~ in known host file names. */
 665         /* XXX mem-leaks: */
 666         options.system_hostfile =
 667             tilde_expand_filename(options.system_hostfile, original_real_uid);
 668         options.user_hostfile =
 669             tilde_expand_filename(options.user_hostfile, original_real_uid);
 670         options.system_hostfile2 =
 671             tilde_expand_filename(options.system_hostfile2, original_real_uid);
 672         options.user_hostfile2 =
 673             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 674
 675         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 676
 677         /* Log into the remote system.  This never returns if the login fails. */
 678         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw);
 679
 680         /* We no longer need the private host keys.  Clear them now. */
 681         if (sensitive_data.nkeys != 0) {
 682                 for (i = 0; i < sensitive_data.nkeys; i++) {
 683                         if (sensitive_data.keys[i] != NULL) {
 684                                 /* Destroys contents safely */
 685                                 debug3("clear hostkey %d", i);
 686                                 key_free(sensitive_data.keys[i]);
 687                                 sensitive_data.keys[i] = NULL;
 688                         }
 689                 }
 690                 xfree(sensitive_data.keys);
 691         }
 692         for (i = 0; i < options.num_identity_files; i++) {
 693                 if (options.identity_files[i]) {
 694                         xfree(options.identity_files[i]);
 695                         options.identity_files[i] = NULL;
 696                 }
 697                 if (options.identity_keys[i]) {
 698                         key_free(options.identity_keys[i]);
 699                         options.identity_keys[i] = NULL;
 700                 }
 701         }
 702
 703         exit_status = compat20 ? ssh_session2() : ssh_session();
 704         packet_close();
 705
 706         /*
 707          * Send SIGHUP to proxy command if used. We don't wait() in
 708          * case it hangs and instead rely on init to reap the child
 709          */
 710         if (proxy_command_pid > 1)
 711                 kill(proxy_command_pid, SIGHUP);
 712
 713         return exit_status;
 714 }
 715
 716 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
 717
 718 static void
 719 x11_get_proto(char **_proto, char **_data)
 720 {
 721         char cmd[1024];
 722         char line[512];
 723         char xdisplay[512];
 724         static char proto[512], data[512];
 725         FILE *f;
 726         int got_data = 0, generated = 0, do_unlink = 0, i;
 727         char *display, *xauthdir, *xauthfile;
 728         struct stat st;
 729
 730         xauthdir = xauthfile = NULL;
 731         *_proto = proto;
 732         *_data = data;
 733         proto[0] = data[0] = '\0';
 734
 735         if (!options.xauth_location ||
 736             (stat(options.xauth_location, &st) == -1)) {
 737                 debug("No xauth program.");
 738         } else {
 739                 if ((display = getenv("DISPLAY")) == NULL) {
 740                         debug("x11_get_proto: DISPLAY not set");
 741                         return;
 742                 }
 743                 /*
 744                  * Handle FamilyLocal case where $DISPLAY does
 745                  * not match an authorization entry.  For this we
 746                  * just try "xauth list unix:displaynum.screennum".
 747                  * XXX: "localhost" match to determine FamilyLocal
 748                  *      is not perfect.
 749                  */
 750                 if (strncmp(display, "localhost:", 10) == 0) {
 751                         snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
 752                             display + 10);
 753                         display = xdisplay;
 754                 }
 755                 if (options.forward_x11_trusted == 0) {
 756                         xauthdir = xmalloc(MAXPATHLEN);
 757                         xauthfile = xmalloc(MAXPATHLEN);
 758                         strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
 759                         if (mkdtemp(xauthdir) != NULL) {
 760                                 do_unlink = 1;
 761                                 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile",
 762                                     xauthdir);
 763                                 snprintf(cmd, sizeof(cmd),
 764                                     "%s -f %s generate %s " SSH_X11_PROTO
 765                                     " untrusted timeout 1200 2>" _PATH_DEVNULL,
 766                                     options.xauth_location, xauthfile, display);
 767                                 debug2("x11_get_proto: %s", cmd);
 768                                 if (system(cmd) == 0)
 769                                         generated = 1;
 770                         }
 771                 }
 772                 snprintf(cmd, sizeof(cmd),
 773                     "%s %s%s list %s . 2>" _PATH_DEVNULL,
 774                     options.xauth_location,
 775                     generated ? "-f " : "" ,
 776                     generated ? xauthfile : "",
 777                     display);
 778                 debug2("x11_get_proto: %s", cmd);
 779                 f = popen(cmd, "r");
 780                 if (f && fgets(line, sizeof(line), f) &&
 781                     sscanf(line, "%*s %511s %511s", proto, data) == 2)
 782                         got_data = 1;
 783                 if (f)
 784                         pclose(f);
 785         }
 786
 787         if (do_unlink) {
 788                 unlink(xauthfile);
 789                 rmdir(xauthdir);
 790         }
 791         if (xauthdir)
 792                 xfree(xauthdir);
 793         if (xauthfile)
 794                 xfree(xauthfile);
 795
 796         /*
 797          * If we didn't get authentication data, just make up some
 798          * data.  The forwarding code will check the validity of the
 799          * response anyway, and substitute this data.  The X11
 800          * server, however, will ignore this fake data and use
 801          * whatever authentication mechanisms it was using otherwise
 802          * for the local connection.
 803          */
 804         if (!got_data) {
 805                 u_int32_t rand = 0;
 806
 807                 logit("Warning: No xauth data; "
 808                     "using fake authentication data for X11 forwarding.");
 809                 strlcpy(proto, SSH_X11_PROTO, sizeof proto);
 810                 for (i = 0; i < 16; i++) {
 811                         if (i % 4 == 0)
 812                                 rand = arc4random();
 813                         snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
 814                             rand & 0xff);
 815                         rand >>= 8;
 816                 }
 817         }
 818 }
 819
 820 static void
 821 ssh_init_forwarding(void)
 822 {
 823         int success = 0;
 824         int i;
 825
 826         /* Initiate local TCP/IP port forwardings. */
 827         for (i = 0; i < options.num_local_forwards; i++) {
 828                 debug("Connections to local port %d forwarded to remote address %.200s:%d",
 829                     options.local_forwards[i].port,
 830                     options.local_forwards[i].host,
 831                     options.local_forwards[i].host_port);
 832                 success += channel_setup_local_fwd_listener(
 833                     options.local_forwards[i].port,
 834                     options.local_forwards[i].host,
 835                     options.local_forwards[i].host_port,
 836                     options.gateway_ports);
 837         }
 838         if (i > 0 && success == 0)
 839                 error("Could not request local forwarding.");
 840
 841         /* Initiate remote TCP/IP port forwardings. */
 842         for (i = 0; i < options.num_remote_forwards; i++) {
 843                 debug("Connections to remote port %d forwarded to local address %.200s:%d",
 844                     options.remote_forwards[i].port,
 845                     options.remote_forwards[i].host,
 846                     options.remote_forwards[i].host_port);
 847                 channel_request_remote_forwarding(
 848                     options.remote_forwards[i].port,
 849                     options.remote_forwards[i].host,
 850                     options.remote_forwards[i].host_port);
 851         }
 852 }
 853
 854 static void
 855 check_agent_present(void)
 856 {
 857         if (options.forward_agent) {
 858                 /* Clear agent forwarding if we don\'t have an agent. */
 859                 if (!ssh_agent_present())
 860                         options.forward_agent = 0;
 861         }
 862 }
 863
 864 static int
 865 ssh_session(void)
 866 {
 867         int type;
 868         int interactive = 0;
 869         int have_tty = 0;
 870         struct winsize ws;
 871         char *cp;
 872
 873         /* Enable compression if requested. */
 874         if (options.compression) {
 875                 debug("Requesting compression at level %d.", options.compression_level);
 876
 877                 if (options.compression_level < 1 || options.compression_level > 9)
 878                         fatal("Compression level must be from 1 (fast) to 9 (slow, best).");
 879
 880                 /* Send the request. */
 881                 packet_start(SSH_CMSG_REQUEST_COMPRESSION);
 882                 packet_put_int(options.compression_level);
 883                 packet_send();
 884                 packet_write_wait();
 885                 type = packet_read();
 886                 if (type == SSH_SMSG_SUCCESS)
 887                         packet_start_compression(options.compression_level);
 888                 else if (type == SSH_SMSG_FAILURE)
 889                         logit("Warning: Remote host refused compression.");
 890                 else
 891                         packet_disconnect("Protocol error waiting for compression response.");
 892         }
 893         /* Allocate a pseudo tty if appropriate. */
 894         if (tty_flag) {
 895                 debug("Requesting pty.");
 896
 897                 /* Start the packet. */
 898                 packet_start(SSH_CMSG_REQUEST_PTY);
 899
 900                 /* Store TERM in the packet.  There is no limit on the
 901                    length of the string. */
 902                 cp = getenv("TERM");
 903                 if (!cp)
 904                         cp = "";
 905                 packet_put_cstring(cp);
 906
 907                 /* Store window size in the packet. */
 908                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
 909                         memset(&ws, 0, sizeof(ws));
 910                 packet_put_int(ws.ws_row);
 911                 packet_put_int(ws.ws_col);
 912                 packet_put_int(ws.ws_xpixel);
 913                 packet_put_int(ws.ws_ypixel);
 914
 915                 /* Store tty modes in the packet. */
 916                 tty_make_modes(fileno(stdin), NULL);
 917
 918                 /* Send the packet, and wait for it to leave. */
 919                 packet_send();
 920                 packet_write_wait();
 921
 922                 /* Read response from the server. */
 923                 type = packet_read();
 924                 if (type == SSH_SMSG_SUCCESS) {
 925                         interactive = 1;
 926                         have_tty = 1;
 927                 } else if (type == SSH_SMSG_FAILURE)
 928                         logit("Warning: Remote host failed or refused to allocate a pseudo tty.");
 929                 else
 930                         packet_disconnect("Protocol error waiting for pty request response.");
 931         }
 932         /* Request X11 forwarding if enabled and DISPLAY is set. */
 933         if (options.forward_x11 && getenv("DISPLAY") != NULL) {
 934                 char *proto, *data;
 935                 /* Get reasonable local authentication information. */
 936                 x11_get_proto(&proto, &data);
 937                 /* Request forwarding with authentication spoofing. */
 938                 debug("Requesting X11 forwarding with authentication spoofing.");
 939                 x11_request_forwarding_with_spoofing(0, proto, data);
 940
 941                 /* Read response from the server. */
 942                 type = packet_read();
 943                 if (type == SSH_SMSG_SUCCESS) {
 944                         interactive = 1;
 945                 } else if (type == SSH_SMSG_FAILURE) {
 946                         logit("Warning: Remote host denied X11 forwarding.");
 947                 } else {
 948                         packet_disconnect("Protocol error waiting for X11 forwarding");
 949                 }
 950         }
 951         /* Tell the packet module whether this is an interactive session. */
 952         packet_set_interactive(interactive);
 953
 954         /* Request authentication agent forwarding if appropriate. */
 955         check_agent_present();
 956
 957         if (options.forward_agent) {
 958                 debug("Requesting authentication agent forwarding.");
 959                 auth_request_forwarding();
 960
 961                 /* Read response from the server. */
 962                 type = packet_read();
 963                 packet_check_eom();
 964                 if (type != SSH_SMSG_SUCCESS)
 965                         logit("Warning: Remote host denied authentication agent forwarding.");
 966         }
 967
 968         /* Initiate port forwardings. */
 969         ssh_init_forwarding();
 970
 971         /* If requested, let ssh continue in the background. */
 972         if (fork_after_authentication_flag)
 973                 if (daemon(1, 1) < 0)
 974                         fatal("daemon() failed: %.200s", strerror(errno));
 975
 976         /*
 977          * If a command was specified on the command line, execute the
 978          * command now. Otherwise request the server to start a shell.
 979          */
 980         if (buffer_len(&command) > 0) {
 981                 int len = buffer_len(&command);
 982                 if (len > 900)
 983                         len = 900;
 984                 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
 985                 packet_start(SSH_CMSG_EXEC_CMD);
 986                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
 987                 packet_send();
 988                 packet_write_wait();
 989         } else {
 990                 debug("Requesting shell.");
 991                 packet_start(SSH_CMSG_EXEC_SHELL);
 992                 packet_send();
 993                 packet_write_wait();
 994         }
 995
 996         /* Enter the interactive session. */
 997         return client_loop(have_tty, tty_flag ?
 998             options.escape_char : SSH_ESCAPECHAR_NONE, 0);
 999 }
1000
1001 static void
1002 client_subsystem_reply(int type, u_int32_t seq, void *ctxt)
1003 {
1004         int id, len;
1005
1006         id = packet_get_int();
1007         len = buffer_len(&command);
1008         if (len > 900)
1009                 len = 900;
1010         packet_check_eom();
1011         if (type == SSH2_MSG_CHANNEL_FAILURE)
1012                 fatal("Request for subsystem '%.*s' failed on channel %d",
1013                     len, (u_char *)buffer_ptr(&command), id);
1014 }
1015
1016 void
1017 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt)
1018 {
1019         int i;
1020
1021         i = client_global_request_id++;
1022         if (i >= options.num_remote_forwards)
1023                 return;
1024         debug("remote forward %s for: listen %d, connect %s:%d",
1025             type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
1026             options.remote_forwards[i].port,
1027             options.remote_forwards[i].host,
1028             options.remote_forwards[i].host_port);
1029         if (type == SSH2_MSG_REQUEST_FAILURE)
1030                 logit("Warning: remote port forwarding failed for listen port %d",
1031                     options.remote_forwards[i].port);
1032 }
1033
1034 /* request pty/x11/agent/tcpfwd/shell for channel */
1035 static void
1036 ssh_session2_setup(int id, void *arg)
1037 {
1038         int len;
1039         int interactive = 0;
1040         struct termios tio;
1041
1042         debug2("ssh_session2_setup: id %d", id);
1043
1044         if (tty_flag) {
1045                 struct winsize ws;
1046                 char *cp;
1047                 cp = getenv("TERM");
1048                 if (!cp)
1049                         cp = "";
1050                 /* Store window size in the packet. */
1051                 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
1052                         memset(&ws, 0, sizeof(ws));
1053
1054                 channel_request_start(id, "pty-req", 0);
1055                 packet_put_cstring(cp);
1056                 packet_put_int(ws.ws_col);
1057                 packet_put_int(ws.ws_row);
1058                 packet_put_int(ws.ws_xpixel);
1059                 packet_put_int(ws.ws_ypixel);
1060                 tio = get_saved_tio();
1061                 tty_make_modes(/*ignored*/ 0, &tio);
1062                 packet_send();
1063                 interactive = 1;
1064                 /* XXX wait for reply */
1065         }
1066         if (options.forward_x11 &&
1067             getenv("DISPLAY") != NULL) {
1068                 char *proto, *data;
1069                 /* Get reasonable local authentication information. */
1070                 x11_get_proto(&proto, &data);
1071                 /* Request forwarding with authentication spoofing. */
1072                 debug("Requesting X11 forwarding with authentication spoofing.");
1073                 x11_request_forwarding_with_spoofing(id, proto, data);
1074                 interactive = 1;
1075                 /* XXX wait for reply */
1076         }
1077
1078         check_agent_present();
1079         if (options.forward_agent) {
1080                 debug("Requesting authentication agent forwarding.");
1081                 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1082                 packet_send();
1083         }
1084
1085         len = buffer_len(&command);
1086         if (len > 0) {
1087                 if (len > 900)
1088                         len = 900;
1089                 if (subsystem_flag) {
1090                         debug("Sending subsystem: %.*s", len, (u_char *)buffer_ptr(&command));
1091                         channel_request_start(id, "subsystem", /*want reply*/ 1);
1092                         /* register callback for reply */
1093                         /* XXX we assume that client_loop has already been called */
1094                         dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply);
1095                         dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply);
1096                 } else {
1097                         debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
1098                         channel_request_start(id, "exec", 0);
1099                 }
1100                 packet_put_string(buffer_ptr(&command), buffer_len(&command));
1101                 packet_send();
1102         } else {
1103                 channel_request_start(id, "shell", 0);
1104                 packet_send();
1105         }
1106
1107         packet_set_interactive(interactive);
1108 }
1109
1110 /* open new channel for a session */
1111 static int
1112 ssh_session2_open(void)
1113 {
1114         Channel *c;
1115         int window, packetmax, in, out, err;
1116
1117         if (stdin_null_flag) {
1118                 in = open(_PATH_DEVNULL, O_RDONLY);
1119         } else {
1120                 in = dup(STDIN_FILENO);
1121         }
1122         out = dup(STDOUT_FILENO);
1123         err = dup(STDERR_FILENO);
1124
1125         if (in < 0 || out < 0 || err < 0)
1126                 fatal("dup() in/out/err failed");
1127
1128         /* enable nonblocking unless tty */
1129         if (!isatty(in))
1130                 set_nonblock(in);
1131         if (!isatty(out))
1132                 set_nonblock(out);
1133         if (!isatty(err))
1134                 set_nonblock(err);
1135
1136         window = CHAN_SES_WINDOW_DEFAULT;
1137         packetmax = CHAN_SES_PACKET_DEFAULT;
1138         if (tty_flag) {
1139                 window >>= 1;
1140                 packetmax >>= 1;
1141         }
1142         c = channel_new(
1143             "session", SSH_CHANNEL_OPENING, in, out, err,
1144             window, packetmax, CHAN_EXTENDED_WRITE,
1145             "client-session", /*nonblock*/0);
1146
1147         debug3("ssh_session2_open: channel_new: %d", c->self);
1148
1149         channel_send_open(c->self);
1150         if (!no_shell_flag)
1151                 channel_register_confirm(c->self, ssh_session2_setup);
1152
1153         return c->self;
1154 }
1155
1156 static int
1157 ssh_session2(void)
1158 {
1159         int id = -1;
1160
1161         /* XXX should be pre-session */
1162         ssh_init_forwarding();
1163
1164         if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN))
1165                 id = ssh_session2_open();
1166
1167         /* If requested, let ssh continue in the background. */
1168         if (fork_after_authentication_flag)
1169                 if (daemon(1, 1) < 0)
1170                         fatal("daemon() failed: %.200s", strerror(errno));
1171
1172         return client_loop(tty_flag, tty_flag ?
1173             options.escape_char : SSH_ESCAPECHAR_NONE, id);
1174 }
1175
1176 static void
1177 load_public_identity_files(void)
1178 {
1179         char *filename;
1180         int i = 0;
1181         Key *public;
1182 #ifdef SMARTCARD
1183         Key **keys;
1184
1185         if (options.smartcard_device != NULL &&
1186             options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
1187             (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL ) {
1188                 int count = 0;
1189                 for (i = 0; keys[i] != NULL; i++) {
1190                         count++;
1191                         memmove(&options.identity_files[1], &options.identity_files[0],
1192                             sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
1193                         memmove(&options.identity_keys[1], &options.identity_keys[0],
1194                             sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
1195                         options.num_identity_files++;
1196                         options.identity_keys[0] = keys[i];
1197                         options.identity_files[0] = sc_get_key_label(keys[i]);
1198                 }
1199                 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
1200                         options.num_identity_files = SSH_MAX_IDENTITY_FILES;
1201                 i = count;
1202                 xfree(keys);
1203         }
1204 #endif /* SMARTCARD */
1205         for (; i < options.num_identity_files; i++) {
1206                 filename = tilde_expand_filename(options.identity_files[i],
1207                     original_real_uid);
1208                 public = key_load_public(filename, NULL);
1209                 debug("identity file %s type %d", filename,
1210                     public ? public->type : -1);
1211                 xfree(options.identity_files[i]);
1212                 options.identity_files[i] = filename;
1213                 options.identity_keys[i] = public;
1214         }
1215 }