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 1.249 2005/07/30 01:26:16 djm Exp $"); 44 RCSID("$FreeBSD$"); 45 46 #include <openssl/evp.h> 47 #include <openssl/err.h> 48 49 #include "ssh.h" 50 #include "ssh1.h" 51 #include "ssh2.h" 52 #include "compat.h" 53 #include "cipher.h" 54 #include "xmalloc.h" 55 #include "packet.h" 56 #include "buffer.h" 57 #include "bufaux.h" 58 #include "channels.h" 59 #include "key.h" 60 #include "authfd.h" 61 #include "authfile.h" 62 #include "pathnames.h" 63 #include "dispatch.h" 64 #include "clientloop.h" 65 #include "log.h" 66 #include "readconf.h" 67 #include "sshconnect.h" 68 #include "misc.h" 69 #include "kex.h" 70 #include "mac.h" 71 #include "sshpty.h" 72 #include "match.h" 73 #include "msg.h" 74 #include "monitor_fdpass.h" 75 #include "uidswap.h" 76 77 #ifdef SMARTCARD 78 #include "scard.h" 79 #endif 80 81 extern char *__progname; 82 83 /* Flag indicating whether debug mode is on. This can be set on the command line. */ 84 int debug_flag = 0; 85 86 /* Flag indicating whether a tty should be allocated */ 87 int tty_flag = 0; 88 int no_tty_flag = 0; 89 int force_tty_flag = 0; 90 91 /* don't exec a shell */ 92 int no_shell_flag = 0; 93 94 /* 95 * Flag indicating that nothing should be read from stdin. This can be set 96 * on the command line. 97 */ 98 int stdin_null_flag = 0; 99 100 /* 101 * Flag indicating that ssh should fork after authentication. This is useful 102 * so that the passphrase can be entered manually, and then ssh goes to the 103 * background. 104 */ 105 int fork_after_authentication_flag = 0; 106 107 /* 108 * General data structure for command line options and options configurable 109 * in configuration files. See readconf.h. 110 */ 111 Options options; 112 113 /* optional user configfile */ 114 char *config = NULL; 115 116 /* 117 * Name of the host we are connecting to. This is the name given on the 118 * command line, or the HostName specified for the user-supplied name in a 119 * configuration file. 120 */ 121 char *host; 122 123 /* socket address the host resolves to */ 124 struct sockaddr_storage hostaddr; 125 126 /* Private host keys. */ 127 Sensitive sensitive_data; 128 129 /* Original real UID. */ 130 uid_t original_real_uid; 131 uid_t original_effective_uid; 132 133 /* command to be executed */ 134 Buffer command; 135 136 /* Should we execute a command or invoke a subsystem? */ 137 int subsystem_flag = 0; 138 139 /* # of replies received for global requests */ 140 static int client_global_request_id = 0; 141 142 /* pid of proxycommand child process */ 143 pid_t proxy_command_pid = 0; 144 145 /* fd to control socket */ 146 int control_fd = -1; 147 148 /* Multiplexing control command */ 149 static u_int mux_command = 0; 150 151 /* Only used in control client mode */ 152 volatile sig_atomic_t control_client_terminate = 0; 153 u_int control_server_pid = 0; 154 155 /* Prints a help message to the user. This function never returns. */ 156 157 static void 158 usage(void) 159 { 160 fprintf(stderr, 161 "usage: ssh [-1246AaCfgkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n" 162 " [-D port] [-e escape_char] [-F configfile]\n" 163 " [-i identity_file] [-L [bind_address:]port:host:hostport]\n" 164 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n" 165 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n" 166 " [user@]hostname [command]\n" 167 ); 168 exit(1); 169 } 170 171 static int ssh_session(void); 172 static int ssh_session2(void); 173 static void load_public_identity_files(void); 174 static void control_client(const char *path); 175 176 /* 177 * Main program for the ssh client. 178 */ 179 int 180 main(int ac, char **av) 181 { 182 int i, opt, exit_status; 183 char *p, *cp, *line, buf[256]; 184 struct stat st; 185 struct passwd *pw; 186 int dummy; 187 extern int optind, optreset; 188 extern char *optarg; 189 struct servent *sp; 190 Forward fwd; 191 192 __progname = ssh_get_progname(av[0]); 193 init_rng(); 194 195 /* 196 * Save the original real uid. It will be needed later (uid-swapping 197 * may clobber the real uid). 198 */ 199 original_real_uid = getuid(); 200 original_effective_uid = geteuid(); 201 202 /* 203 * Use uid-swapping to give up root privileges for the duration of 204 * option processing. We will re-instantiate the rights when we are 205 * ready to create the privileged port, and will permanently drop 206 * them when the port has been created (actually, when the connection 207 * has been made, as we may need to create the port several times). 208 */ 209 PRIV_END; 210 211 #ifdef HAVE_SETRLIMIT 212 /* If we are installed setuid root be careful to not drop core. */ 213 if (original_real_uid != original_effective_uid) { 214 struct rlimit rlim; 215 rlim.rlim_cur = rlim.rlim_max = 0; 216 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 217 fatal("setrlimit failed: %.100s", strerror(errno)); 218 } 219 #endif 220 /* Get user data. */ 221 pw = getpwuid(original_real_uid); 222 if (!pw) { 223 logit("You don't exist, go away!"); 224 exit(1); 225 } 226 /* Take a copy of the returned structure. */ 227 pw = pwcopy(pw); 228 229 /* 230 * Set our umask to something reasonable, as some files are created 231 * with the default umask. This will make them world-readable but 232 * writable only by the owner, which is ok for all files for which we 233 * don't set the modes explicitly. 234 */ 235 umask(022); 236 237 /* Initialize option structure to indicate that no values have been set. */ 238 initialize_options(&options); 239 240 /* Parse command-line arguments. */ 241 host = NULL; 242 243 again: 244 while ((opt = getopt(ac, av, 245 "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNO:PR:S:TVXY")) != -1) { 246 switch (opt) { 247 case '1': 248 options.protocol = SSH_PROTO_1; 249 break; 250 case '2': 251 options.protocol = SSH_PROTO_2; 252 break; 253 case '4': 254 options.address_family = AF_INET; 255 break; 256 case '6': 257 options.address_family = AF_INET6; 258 break; 259 case 'n': 260 stdin_null_flag = 1; 261 break; 262 case 'f': 263 fork_after_authentication_flag = 1; 264 stdin_null_flag = 1; 265 break; 266 case 'x': 267 options.forward_x11 = 0; 268 break; 269 case 'X': 270 options.forward_x11 = 1; 271 break; 272 case 'Y': 273 options.forward_x11 = 1; 274 options.forward_x11_trusted = 1; 275 break; 276 case 'g': 277 options.gateway_ports = 1; 278 break; 279 case 'O': 280 if (strcmp(optarg, "check") == 0) 281 mux_command = SSHMUX_COMMAND_ALIVE_CHECK; 282 else if (strcmp(optarg, "exit") == 0) 283 mux_command = SSHMUX_COMMAND_TERMINATE; 284 else 285 fatal("Invalid multiplex command."); 286 break; 287 case 'P': /* deprecated */ 288 options.use_privileged_port = 0; 289 break; 290 case 'a': 291 options.forward_agent = 0; 292 break; 293 case 'A': 294 options.forward_agent = 1; 295 break; 296 case 'k': 297 options.gss_deleg_creds = 0; 298 break; 299 case 'i': 300 if (stat(optarg, &st) < 0) { 301 fprintf(stderr, "Warning: Identity file %s " 302 "not accessible: %s.\n", optarg, 303 strerror(errno)); 304 break; 305 } 306 if (options.num_identity_files >= 307 SSH_MAX_IDENTITY_FILES) 308 fatal("Too many identity files specified " 309 "(max %d)", SSH_MAX_IDENTITY_FILES); 310 options.identity_files[options.num_identity_files++] = 311 xstrdup(optarg); 312 break; 313 case 'I': 314 #ifdef SMARTCARD 315 options.smartcard_device = xstrdup(optarg); 316 #else 317 fprintf(stderr, "no support for smartcards.\n"); 318 #endif 319 break; 320 case 't': 321 if (tty_flag) 322 force_tty_flag = 1; 323 tty_flag = 1; 324 break; 325 case 'v': 326 if (debug_flag == 0) { 327 debug_flag = 1; 328 options.log_level = SYSLOG_LEVEL_DEBUG1; 329 } else { 330 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 331 options.log_level++; 332 break; 333 } 334 /* FALLTHROUGH */ 335 case 'V': 336 fprintf(stderr, "%s, %s\n", 337 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); 338 if (opt == 'V') 339 exit(0); 340 break; 341 case 'q': 342 options.log_level = SYSLOG_LEVEL_QUIET; 343 break; 344 case 'e': 345 if (optarg[0] == '^' && optarg[2] == 0 && 346 (u_char) optarg[1] >= 64 && 347 (u_char) optarg[1] < 128) 348 options.escape_char = (u_char) optarg[1] & 31; 349 else if (strlen(optarg) == 1) 350 options.escape_char = (u_char) optarg[0]; 351 else if (strcmp(optarg, "none") == 0) 352 options.escape_char = SSH_ESCAPECHAR_NONE; 353 else { 354 fprintf(stderr, "Bad escape character '%s'.\n", 355 optarg); 356 exit(1); 357 } 358 break; 359 case 'c': 360 if (ciphers_valid(optarg)) { 361 /* SSH2 only */ 362 options.ciphers = xstrdup(optarg); 363 options.cipher = SSH_CIPHER_INVALID; 364 } else { 365 /* SSH1 only */ 366 options.cipher = cipher_number(optarg); 367 if (options.cipher == -1) { 368 fprintf(stderr, 369 "Unknown cipher type '%s'\n", 370 optarg); 371 exit(1); 372 } 373 if (options.cipher == SSH_CIPHER_3DES) 374 options.ciphers = "3des-cbc"; 375 else if (options.cipher == SSH_CIPHER_BLOWFISH) 376 options.ciphers = "blowfish-cbc"; 377 else 378 options.ciphers = (char *)-1; 379 } 380 break; 381 case 'm': 382 if (mac_valid(optarg)) 383 options.macs = xstrdup(optarg); 384 else { 385 fprintf(stderr, "Unknown mac type '%s'\n", 386 optarg); 387 exit(1); 388 } 389 break; 390 case 'M': 391 if (options.control_master == SSHCTL_MASTER_YES) 392 options.control_master = SSHCTL_MASTER_ASK; 393 else 394 options.control_master = SSHCTL_MASTER_YES; 395 break; 396 case 'p': 397 options.port = a2port(optarg); 398 if (options.port == 0) { 399 fprintf(stderr, "Bad port '%s'\n", optarg); 400 exit(1); 401 } 402 break; 403 case 'l': 404 options.user = optarg; 405 break; 406 407 case 'L': 408 if (parse_forward(&fwd, optarg)) 409 add_local_forward(&options, &fwd); 410 else { 411 fprintf(stderr, 412 "Bad local forwarding specification '%s'\n", 413 optarg); 414 exit(1); 415 } 416 break; 417 418 case 'R': 419 if (parse_forward(&fwd, optarg)) { 420 add_remote_forward(&options, &fwd); 421 } else { 422 fprintf(stderr, 423 "Bad remote forwarding specification " 424 "'%s'\n", optarg); 425 exit(1); 426 } 427 break; 428 429 case 'D': 430 cp = p = xstrdup(optarg); 431 memset(&fwd, '\0', sizeof(fwd)); 432 fwd.connect_host = "socks"; 433 if ((fwd.listen_host = hpdelim(&cp)) == NULL) { 434 fprintf(stderr, "Bad dynamic forwarding " 435 "specification '%.100s'\n", optarg); 436 exit(1); 437 } 438 if (cp != NULL) { 439 fwd.listen_port = a2port(cp); 440 fwd.listen_host = cleanhostname(fwd.listen_host); 441 } else { 442 fwd.listen_port = a2port(fwd.listen_host); 443 fwd.listen_host = NULL; 444 } 445 446 if (fwd.listen_port == 0) { 447 fprintf(stderr, "Bad dynamic port '%s'\n", 448 optarg); 449 exit(1); 450 } 451 add_local_forward(&options, &fwd); 452 xfree(p); 453 break; 454 455 case 'C': 456 options.compression = 1; 457 break; 458 case 'N': 459 no_shell_flag = 1; 460 no_tty_flag = 1; 461 break; 462 case 'T': 463 no_tty_flag = 1; 464 break; 465 case 'o': 466 dummy = 1; 467 line = xstrdup(optarg); 468 if (process_config_line(&options, host ? host : "", 469 line, "command-line", 0, &dummy) != 0) 470 exit(1); 471 xfree(line); 472 break; 473 case 's': 474 subsystem_flag = 1; 475 break; 476 case 'S': 477 if (options.control_path != NULL) 478 free(options.control_path); 479 options.control_path = xstrdup(optarg); 480 break; 481 case 'b': 482 options.bind_address = optarg; 483 break; 484 case 'F': 485 config = optarg; 486 break; 487 default: 488 usage(); 489 } 490 } 491 492 ac -= optind; 493 av += optind; 494 495 if (ac > 0 && !host && **av != '-') { 496 if (strrchr(*av, '@')) { 497 p = xstrdup(*av); 498 cp = strrchr(p, '@'); 499 if (cp == NULL || cp == p) 500 usage(); 501 options.user = p; 502 *cp = '\0'; 503 host = ++cp; 504 } else 505 host = *av; 506 if (ac > 1) { 507 optind = optreset = 1; 508 goto again; 509 } 510 ac--, av++; 511 } 512 513 /* Check that we got a host name. */ 514 if (!host) 515 usage(); 516 517 SSLeay_add_all_algorithms(); 518 ERR_load_crypto_strings(); 519 520 /* Initialize the command to execute on remote host. */ 521 buffer_init(&command); 522 523 /* 524 * Save the command to execute on the remote host in a buffer. There 525 * is no limit on the length of the command, except by the maximum 526 * packet size. Also sets the tty flag if there is no command. 527 */ 528 if (!ac) { 529 /* No command specified - execute shell on a tty. */ 530 tty_flag = 1; 531 if (subsystem_flag) { 532 fprintf(stderr, 533 "You must specify a subsystem to invoke.\n"); 534 usage(); 535 } 536 } else { 537 /* A command has been specified. Store it into the buffer. */ 538 for (i = 0; i < ac; i++) { 539 if (i) 540 buffer_append(&command, " ", 1); 541 buffer_append(&command, av[i], strlen(av[i])); 542 } 543 } 544 545 /* Cannot fork to background if no command. */ 546 if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag) 547 fatal("Cannot fork into background without a command to execute."); 548 549 /* Allocate a tty by default if no command specified. */ 550 if (buffer_len(&command) == 0) 551 tty_flag = 1; 552 553 /* Force no tty */ 554 if (no_tty_flag) 555 tty_flag = 0; 556 /* Do not allocate a tty if stdin is not a tty. */ 557 if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) { 558 if (tty_flag) 559 logit("Pseudo-terminal will not be allocated because stdin is not a terminal."); 560 tty_flag = 0; 561 } 562 563 /* 564 * Initialize "log" output. Since we are the client all output 565 * actually goes to stderr. 566 */ 567 log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 568 SYSLOG_FACILITY_USER, 1); 569 570 /* 571 * Read per-user configuration file. Ignore the system wide config 572 * file if the user specifies a config file on the command line. 573 */ 574 if (config != NULL) { 575 if (!read_config_file(config, host, &options, 0)) 576 fatal("Can't open user config file %.100s: " 577 "%.100s", config, strerror(errno)); 578 } else { 579 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, 580 _PATH_SSH_USER_CONFFILE); 581 (void)read_config_file(buf, host, &options, 1); 582 583 /* Read systemwide configuration file after use config. */ 584 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, 585 &options, 0); 586 } 587 588 /* Fill configuration defaults. */ 589 fill_default_options(&options); 590 591 channel_set_af(options.address_family); 592 593 /* reinit */ 594 log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1); 595 596 seed_rng(); 597 598 if (options.user == NULL) 599 options.user = xstrdup(pw->pw_name); 600 601 if (options.hostname != NULL) 602 host = options.hostname; 603 604 /* Find canonic host name. */ 605 if (strchr(host, '.') == 0) { 606 struct addrinfo hints; 607 struct addrinfo *ai = NULL; 608 int errgai; 609 memset(&hints, 0, sizeof(hints)); 610 hints.ai_family = options.address_family; 611 hints.ai_flags = AI_CANONNAME; 612 hints.ai_socktype = SOCK_STREAM; 613 errgai = getaddrinfo(host, NULL, &hints, &ai); 614 if (errgai == 0) { 615 if (ai->ai_canonname != NULL) 616 host = xstrdup(ai->ai_canonname); 617 freeaddrinfo(ai); 618 } 619 } 620 621 /* force lowercase for hostkey matching */ 622 if (options.host_key_alias != NULL) { 623 for (p = options.host_key_alias; *p; p++) 624 if (isupper(*p)) 625 *p = tolower(*p); 626 } 627 628 /* Get default port if port has not been set. */ 629 if (options.port == 0) { 630 sp = getservbyname(SSH_SERVICE_NAME, "tcp"); 631 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; 632 } 633 634 if (options.proxy_command != NULL && 635 strcmp(options.proxy_command, "none") == 0) 636 options.proxy_command = NULL; 637 if (options.control_path != NULL && 638 strcmp(options.control_path, "none") == 0) 639 options.control_path = NULL; 640 641 if (options.control_path != NULL) { 642 snprintf(buf, sizeof(buf), "%d", options.port); 643 cp = tilde_expand_filename(options.control_path, 644 original_real_uid); 645 options.control_path = percent_expand(cp, "p", buf, "h", host, 646 "r", options.user, (char *)NULL); 647 xfree(cp); 648 } 649 if (mux_command != 0 && options.control_path == NULL) 650 fatal("No ControlPath specified for \"-O\" command"); 651 if (options.control_path != NULL) 652 control_client(options.control_path); 653 654 /* Open a connection to the remote host. */ 655 if (ssh_connect(host, &hostaddr, options.port, 656 options.address_family, options.connection_attempts, 657 #ifdef HAVE_CYGWIN 658 options.use_privileged_port, 659 #else 660 original_effective_uid == 0 && options.use_privileged_port, 661 #endif 662 options.proxy_command) != 0) 663 exit(1); 664 665 /* 666 * If we successfully made the connection, load the host private key 667 * in case we will need it later for combined rsa-rhosts 668 * authentication. This must be done before releasing extra 669 * privileges, because the file is only readable by root. 670 * If we cannot access the private keys, load the public keys 671 * instead and try to execute the ssh-keysign helper instead. 672 */ 673 sensitive_data.nkeys = 0; 674 sensitive_data.keys = NULL; 675 sensitive_data.external_keysign = 0; 676 if (options.rhosts_rsa_authentication || 677 options.hostbased_authentication) { 678 sensitive_data.nkeys = 3; 679 sensitive_data.keys = xmalloc(sensitive_data.nkeys * 680 sizeof(Key)); 681 682 PRIV_START; 683 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 684 _PATH_HOST_KEY_FILE, "", NULL); 685 sensitive_data.keys[1] = key_load_private_type(KEY_DSA, 686 _PATH_HOST_DSA_KEY_FILE, "", NULL); 687 sensitive_data.keys[2] = key_load_private_type(KEY_RSA, 688 _PATH_HOST_RSA_KEY_FILE, "", NULL); 689 PRIV_END; 690 691 if (options.hostbased_authentication == 1 && 692 sensitive_data.keys[0] == NULL && 693 sensitive_data.keys[1] == NULL && 694 sensitive_data.keys[2] == NULL) { 695 sensitive_data.keys[1] = key_load_public( 696 _PATH_HOST_DSA_KEY_FILE, NULL); 697 sensitive_data.keys[2] = key_load_public( 698 _PATH_HOST_RSA_KEY_FILE, NULL); 699 sensitive_data.external_keysign = 1; 700 } 701 } 702 /* 703 * Get rid of any extra privileges that we may have. We will no 704 * longer need them. Also, extra privileges could make it very hard 705 * to read identity files and other non-world-readable files from the 706 * user's home directory if it happens to be on a NFS volume where 707 * root is mapped to nobody. 708 */ 709 if (original_effective_uid == 0) { 710 PRIV_START; 711 permanently_set_uid(pw); 712 } 713 714 /* 715 * Now that we are back to our own permissions, create ~/.ssh 716 * directory if it doesn\'t already exist. 717 */ 718 snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 719 if (stat(buf, &st) < 0) 720 if (mkdir(buf, 0700) < 0) 721 error("Could not create directory '%.200s'.", buf); 722 723 /* load options.identity_files */ 724 load_public_identity_files(); 725 726 /* Expand ~ in known host file names. */ 727 /* XXX mem-leaks: */ 728 options.system_hostfile = 729 tilde_expand_filename(options.system_hostfile, original_real_uid); 730 options.user_hostfile = 731 tilde_expand_filename(options.user_hostfile, original_real_uid); 732 options.system_hostfile2 = 733 tilde_expand_filename(options.system_hostfile2, original_real_uid); 734 options.user_hostfile2 = 735 tilde_expand_filename(options.user_hostfile2, original_real_uid); 736 737 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 738 739 /* Log into the remote system. This never returns if the login fails. */ 740 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw); 741 742 /* We no longer need the private host keys. Clear them now. */ 743 if (sensitive_data.nkeys != 0) { 744 for (i = 0; i < sensitive_data.nkeys; i++) { 745 if (sensitive_data.keys[i] != NULL) { 746 /* Destroys contents safely */ 747 debug3("clear hostkey %d", i); 748 key_free(sensitive_data.keys[i]); 749 sensitive_data.keys[i] = NULL; 750 } 751 } 752 xfree(sensitive_data.keys); 753 } 754 for (i = 0; i < options.num_identity_files; i++) { 755 if (options.identity_files[i]) { 756 xfree(options.identity_files[i]); 757 options.identity_files[i] = NULL; 758 } 759 if (options.identity_keys[i]) { 760 key_free(options.identity_keys[i]); 761 options.identity_keys[i] = NULL; 762 } 763 } 764 765 exit_status = compat20 ? ssh_session2() : ssh_session(); 766 packet_close(); 767 768 if (options.control_path != NULL && control_fd != -1) 769 unlink(options.control_path); 770 771 /* 772 * Send SIGHUP to proxy command if used. We don't wait() in 773 * case it hangs and instead rely on init to reap the child 774 */ 775 if (proxy_command_pid > 1) 776 kill(proxy_command_pid, SIGHUP); 777 778 return exit_status; 779 } 780 781 static void 782 ssh_init_forwarding(void) 783 { 784 int success = 0; 785 int i; 786 787 /* Initiate local TCP/IP port forwardings. */ 788 for (i = 0; i < options.num_local_forwards; i++) { 789 debug("Local connections to %.200s:%d forwarded to remote " 790 "address %.200s:%d", 791 (options.local_forwards[i].listen_host == NULL) ? 792 (options.gateway_ports ? "*" : "LOCALHOST") : 793 options.local_forwards[i].listen_host, 794 options.local_forwards[i].listen_port, 795 options.local_forwards[i].connect_host, 796 options.local_forwards[i].connect_port); 797 success += channel_setup_local_fwd_listener( 798 options.local_forwards[i].listen_host, 799 options.local_forwards[i].listen_port, 800 options.local_forwards[i].connect_host, 801 options.local_forwards[i].connect_port, 802 options.gateway_ports); 803 } 804 if (i > 0 && success == 0) 805 error("Could not request local forwarding."); 806 807 /* Initiate remote TCP/IP port forwardings. */ 808 for (i = 0; i < options.num_remote_forwards; i++) { 809 debug("Remote connections from %.200s:%d forwarded to " 810 "local address %.200s:%d", 811 (options.remote_forwards[i].listen_host == NULL) ? 812 (options.gateway_ports ? "*" : "LOCALHOST") : 813 options.remote_forwards[i].listen_host, 814 options.remote_forwards[i].listen_port, 815 options.remote_forwards[i].connect_host, 816 options.remote_forwards[i].connect_port); 817 channel_request_remote_forwarding( 818 options.remote_forwards[i].listen_host, 819 options.remote_forwards[i].listen_port, 820 options.remote_forwards[i].connect_host, 821 options.remote_forwards[i].connect_port); 822 } 823 } 824 825 static void 826 check_agent_present(void) 827 { 828 if (options.forward_agent) { 829 /* Clear agent forwarding if we don\'t have an agent. */ 830 if (!ssh_agent_present()) 831 options.forward_agent = 0; 832 } 833 } 834 835 static int 836 ssh_session(void) 837 { 838 int type; 839 int interactive = 0; 840 int have_tty = 0; 841 struct winsize ws; 842 char *cp; 843 const char *display; 844 845 /* Enable compression if requested. */ 846 if (options.compression) { 847 debug("Requesting compression at level %d.", options.compression_level); 848 849 if (options.compression_level < 1 || options.compression_level > 9) 850 fatal("Compression level must be from 1 (fast) to 9 (slow, best)."); 851 852 /* Send the request. */ 853 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 854 packet_put_int(options.compression_level); 855 packet_send(); 856 packet_write_wait(); 857 type = packet_read(); 858 if (type == SSH_SMSG_SUCCESS) 859 packet_start_compression(options.compression_level); 860 else if (type == SSH_SMSG_FAILURE) 861 logit("Warning: Remote host refused compression."); 862 else 863 packet_disconnect("Protocol error waiting for compression response."); 864 } 865 /* Allocate a pseudo tty if appropriate. */ 866 if (tty_flag) { 867 debug("Requesting pty."); 868 869 /* Start the packet. */ 870 packet_start(SSH_CMSG_REQUEST_PTY); 871 872 /* Store TERM in the packet. There is no limit on the 873 length of the string. */ 874 cp = getenv("TERM"); 875 if (!cp) 876 cp = ""; 877 packet_put_cstring(cp); 878 879 /* Store window size in the packet. */ 880 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 881 memset(&ws, 0, sizeof(ws)); 882 packet_put_int(ws.ws_row); 883 packet_put_int(ws.ws_col); 884 packet_put_int(ws.ws_xpixel); 885 packet_put_int(ws.ws_ypixel); 886 887 /* Store tty modes in the packet. */ 888 tty_make_modes(fileno(stdin), NULL); 889 890 /* Send the packet, and wait for it to leave. */ 891 packet_send(); 892 packet_write_wait(); 893 894 /* Read response from the server. */ 895 type = packet_read(); 896 if (type == SSH_SMSG_SUCCESS) { 897 interactive = 1; 898 have_tty = 1; 899 } else if (type == SSH_SMSG_FAILURE) 900 logit("Warning: Remote host failed or refused to allocate a pseudo tty."); 901 else 902 packet_disconnect("Protocol error waiting for pty request response."); 903 } 904 /* Request X11 forwarding if enabled and DISPLAY is set. */ 905 display = getenv("DISPLAY"); 906 if (options.forward_x11 && display != NULL) { 907 char *proto, *data; 908 /* Get reasonable local authentication information. */ 909 client_x11_get_proto(display, options.xauth_location, 910 options.forward_x11_trusted, &proto, &data); 911 /* Request forwarding with authentication spoofing. */ 912 debug("Requesting X11 forwarding with authentication spoofing."); 913 x11_request_forwarding_with_spoofing(0, display, proto, data); 914 915 /* Read response from the server. */ 916 type = packet_read(); 917 if (type == SSH_SMSG_SUCCESS) { 918 interactive = 1; 919 } else if (type == SSH_SMSG_FAILURE) { 920 logit("Warning: Remote host denied X11 forwarding."); 921 } else { 922 packet_disconnect("Protocol error waiting for X11 forwarding"); 923 } 924 } 925 /* Tell the packet module whether this is an interactive session. */ 926 packet_set_interactive(interactive); 927 928 /* Request authentication agent forwarding if appropriate. */ 929 check_agent_present(); 930 931 if (options.forward_agent) { 932 debug("Requesting authentication agent forwarding."); 933 auth_request_forwarding(); 934 935 /* Read response from the server. */ 936 type = packet_read(); 937 packet_check_eom(); 938 if (type != SSH_SMSG_SUCCESS) 939 logit("Warning: Remote host denied authentication agent forwarding."); 940 } 941 942 /* Initiate port forwardings. */ 943 ssh_init_forwarding(); 944 945 /* If requested, let ssh continue in the background. */ 946 if (fork_after_authentication_flag) 947 if (daemon(1, 1) < 0) 948 fatal("daemon() failed: %.200s", strerror(errno)); 949 950 /* 951 * If a command was specified on the command line, execute the 952 * command now. Otherwise request the server to start a shell. 953 */ 954 if (buffer_len(&command) > 0) { 955 int len = buffer_len(&command); 956 if (len > 900) 957 len = 900; 958 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command)); 959 packet_start(SSH_CMSG_EXEC_CMD); 960 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 961 packet_send(); 962 packet_write_wait(); 963 } else { 964 debug("Requesting shell."); 965 packet_start(SSH_CMSG_EXEC_SHELL); 966 packet_send(); 967 packet_write_wait(); 968 } 969 970 /* Enter the interactive session. */ 971 return client_loop(have_tty, tty_flag ? 972 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 973 } 974 975 static void 976 ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt) 977 { 978 int id, len; 979 980 id = packet_get_int(); 981 len = buffer_len(&command); 982 if (len > 900) 983 len = 900; 984 packet_check_eom(); 985 if (type == SSH2_MSG_CHANNEL_FAILURE) 986 fatal("Request for subsystem '%.*s' failed on channel %d", 987 len, (u_char *)buffer_ptr(&command), id); 988 } 989 990 void 991 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt) 992 { 993 int i; 994 995 i = client_global_request_id++; 996 if (i >= options.num_remote_forwards) 997 return; 998 debug("remote forward %s for: listen %d, connect %s:%d", 999 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 1000 options.remote_forwards[i].listen_port, 1001 options.remote_forwards[i].connect_host, 1002 options.remote_forwards[i].connect_port); 1003 if (type == SSH2_MSG_REQUEST_FAILURE) 1004 logit("Warning: remote port forwarding failed for listen " 1005 "port %d", options.remote_forwards[i].listen_port); 1006 } 1007 1008 static void 1009 ssh_control_listener(void) 1010 { 1011 struct sockaddr_un addr; 1012 mode_t old_umask; 1013 int addr_len; 1014 1015 if (options.control_path == NULL || 1016 options.control_master == SSHCTL_MASTER_NO) 1017 return; 1018 1019 debug("setting up multiplex master socket"); 1020 1021 memset(&addr, '\0', sizeof(addr)); 1022 addr.sun_family = AF_UNIX; 1023 addr_len = offsetof(struct sockaddr_un, sun_path) + 1024 strlen(options.control_path) + 1; 1025 1026 if (strlcpy(addr.sun_path, options.control_path, 1027 sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) 1028 fatal("ControlPath too long"); 1029 1030 if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) 1031 fatal("%s socket(): %s\n", __func__, strerror(errno)); 1032 1033 old_umask = umask(0177); 1034 if (bind(control_fd, (struct sockaddr*)&addr, addr_len) == -1) { 1035 control_fd = -1; 1036 if (errno == EINVAL || errno == EADDRINUSE) 1037 fatal("ControlSocket %s already exists", 1038 options.control_path); 1039 else 1040 fatal("%s bind(): %s\n", __func__, strerror(errno)); 1041 } 1042 umask(old_umask); 1043 1044 if (listen(control_fd, 64) == -1) 1045 fatal("%s listen(): %s\n", __func__, strerror(errno)); 1046 1047 set_nonblock(control_fd); 1048 } 1049 1050 /* request pty/x11/agent/tcpfwd/shell for channel */ 1051 static void 1052 ssh_session2_setup(int id, void *arg) 1053 { 1054 extern char **environ; 1055 const char *display; 1056 int interactive = tty_flag; 1057 1058 display = getenv("DISPLAY"); 1059 if (options.forward_x11 && display != NULL) { 1060 char *proto, *data; 1061 /* Get reasonable local authentication information. */ 1062 client_x11_get_proto(display, options.xauth_location, 1063 options.forward_x11_trusted, &proto, &data); 1064 /* Request forwarding with authentication spoofing. */ 1065 debug("Requesting X11 forwarding with authentication spoofing."); 1066 x11_request_forwarding_with_spoofing(id, display, proto, data); 1067 interactive = 1; 1068 /* XXX wait for reply */ 1069 } 1070 1071 check_agent_present(); 1072 if (options.forward_agent) { 1073 debug("Requesting authentication agent forwarding."); 1074 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1075 packet_send(); 1076 } 1077 1078 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1079 NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply); 1080 1081 packet_set_interactive(interactive); 1082 } 1083 1084 /* open new channel for a session */ 1085 static int 1086 ssh_session2_open(void) 1087 { 1088 Channel *c; 1089 int window, packetmax, in, out, err; 1090 1091 if (stdin_null_flag) { 1092 in = open(_PATH_DEVNULL, O_RDONLY); 1093 } else { 1094 in = dup(STDIN_FILENO); 1095 } 1096 out = dup(STDOUT_FILENO); 1097 err = dup(STDERR_FILENO); 1098 1099 if (in < 0 || out < 0 || err < 0) 1100 fatal("dup() in/out/err failed"); 1101 1102 /* enable nonblocking unless tty */ 1103 if (!isatty(in)) 1104 set_nonblock(in); 1105 if (!isatty(out)) 1106 set_nonblock(out); 1107 if (!isatty(err)) 1108 set_nonblock(err); 1109 1110 window = CHAN_SES_WINDOW_DEFAULT; 1111 packetmax = CHAN_SES_PACKET_DEFAULT; 1112 if (tty_flag) { 1113 window >>= 1; 1114 packetmax >>= 1; 1115 } 1116 c = channel_new( 1117 "session", SSH_CHANNEL_OPENING, in, out, err, 1118 window, packetmax, CHAN_EXTENDED_WRITE, 1119 "client-session", /*nonblock*/0); 1120 1121 debug3("ssh_session2_open: channel_new: %d", c->self); 1122 1123 channel_send_open(c->self); 1124 if (!no_shell_flag) 1125 channel_register_confirm(c->self, ssh_session2_setup, NULL); 1126 1127 return c->self; 1128 } 1129 1130 static int 1131 ssh_session2(void) 1132 { 1133 int id = -1; 1134 1135 /* XXX should be pre-session */ 1136 ssh_init_forwarding(); 1137 ssh_control_listener(); 1138 1139 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1140 id = ssh_session2_open(); 1141 1142 /* If requested, let ssh continue in the background. */ 1143 if (fork_after_authentication_flag) 1144 if (daemon(1, 1) < 0) 1145 fatal("daemon() failed: %.200s", strerror(errno)); 1146 1147 return client_loop(tty_flag, tty_flag ? 1148 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1149 } 1150 1151 static void 1152 load_public_identity_files(void) 1153 { 1154 char *filename; 1155 int i = 0; 1156 Key *public; 1157 #ifdef SMARTCARD 1158 Key **keys; 1159 1160 if (options.smartcard_device != NULL && 1161 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1162 (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL ) { 1163 int count = 0; 1164 for (i = 0; keys[i] != NULL; i++) { 1165 count++; 1166 memmove(&options.identity_files[1], &options.identity_files[0], 1167 sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1)); 1168 memmove(&options.identity_keys[1], &options.identity_keys[0], 1169 sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1)); 1170 options.num_identity_files++; 1171 options.identity_keys[0] = keys[i]; 1172 options.identity_files[0] = sc_get_key_label(keys[i]); 1173 } 1174 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES) 1175 options.num_identity_files = SSH_MAX_IDENTITY_FILES; 1176 i = count; 1177 xfree(keys); 1178 } 1179 #endif /* SMARTCARD */ 1180 for (; i < options.num_identity_files; i++) { 1181 filename = tilde_expand_filename(options.identity_files[i], 1182 original_real_uid); 1183 public = key_load_public(filename, NULL); 1184 debug("identity file %s type %d", filename, 1185 public ? public->type : -1); 1186 xfree(options.identity_files[i]); 1187 options.identity_files[i] = filename; 1188 options.identity_keys[i] = public; 1189 } 1190 } 1191 1192 static void 1193 control_client_sighandler(int signo) 1194 { 1195 control_client_terminate = signo; 1196 } 1197 1198 static void 1199 control_client_sigrelay(int signo) 1200 { 1201 if (control_server_pid > 1) 1202 kill(control_server_pid, signo); 1203 } 1204 1205 static int 1206 env_permitted(char *env) 1207 { 1208 int i; 1209 char name[1024], *cp; 1210 1211 strlcpy(name, env, sizeof(name)); 1212 if ((cp = strchr(name, '=')) == NULL) 1213 return (0); 1214 1215 *cp = '\0'; 1216 1217 for (i = 0; i < options.num_send_env; i++) 1218 if (match_pattern(name, options.send_env[i])) 1219 return (1); 1220 1221 return (0); 1222 } 1223 1224 static void 1225 control_client(const char *path) 1226 { 1227 struct sockaddr_un addr; 1228 int i, r, fd, sock, exitval, num_env, addr_len; 1229 Buffer m; 1230 char *term; 1231 extern char **environ; 1232 u_int flags; 1233 1234 if (mux_command == 0) 1235 mux_command = SSHMUX_COMMAND_OPEN; 1236 1237 switch (options.control_master) { 1238 case SSHCTL_MASTER_AUTO: 1239 case SSHCTL_MASTER_AUTO_ASK: 1240 debug("auto-mux: Trying existing master"); 1241 /* FALLTHROUGH */ 1242 case SSHCTL_MASTER_NO: 1243 break; 1244 default: 1245 return; 1246 } 1247 1248 memset(&addr, '\0', sizeof(addr)); 1249 addr.sun_family = AF_UNIX; 1250 addr_len = offsetof(struct sockaddr_un, sun_path) + 1251 strlen(path) + 1; 1252 1253 if (strlcpy(addr.sun_path, path, 1254 sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) 1255 fatal("ControlPath too long"); 1256 1257 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) 1258 fatal("%s socket(): %s", __func__, strerror(errno)); 1259 1260 if (connect(sock, (struct sockaddr*)&addr, addr_len) == -1) { 1261 if (mux_command != SSHMUX_COMMAND_OPEN) { 1262 fatal("Control socket connect(%.100s): %s", path, 1263 strerror(errno)); 1264 } 1265 if (errno == ENOENT) 1266 debug("Control socket \"%.100s\" does not exist", path); 1267 else { 1268 error("Control socket connect(%.100s): %s", path, 1269 strerror(errno)); 1270 } 1271 close(sock); 1272 return; 1273 } 1274 1275 if (stdin_null_flag) { 1276 if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1277 fatal("open(/dev/null): %s", strerror(errno)); 1278 if (dup2(fd, STDIN_FILENO) == -1) 1279 fatal("dup2: %s", strerror(errno)); 1280 if (fd > STDERR_FILENO) 1281 close(fd); 1282 } 1283 1284 term = getenv("TERM"); 1285 1286 flags = 0; 1287 if (tty_flag) 1288 flags |= SSHMUX_FLAG_TTY; 1289 if (subsystem_flag) 1290 flags |= SSHMUX_FLAG_SUBSYS; 1291 if (options.forward_x11) 1292 flags |= SSHMUX_FLAG_X11_FWD; 1293 if (options.forward_agent) 1294 flags |= SSHMUX_FLAG_AGENT_FWD; 1295 1296 buffer_init(&m); 1297 1298 /* Send our command to server */ 1299 buffer_put_int(&m, mux_command); 1300 buffer_put_int(&m, flags); 1301 if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1) 1302 fatal("%s: msg_send", __func__); 1303 buffer_clear(&m); 1304 1305 /* Get authorisation status and PID of controlee */ 1306 if (ssh_msg_recv(sock, &m) == -1) 1307 fatal("%s: msg_recv", __func__); 1308 if (buffer_get_char(&m) != SSHMUX_VER) 1309 fatal("%s: wrong version", __func__); 1310 if (buffer_get_int(&m) != 1) 1311 fatal("Connection to master denied"); 1312 control_server_pid = buffer_get_int(&m); 1313 1314 buffer_clear(&m); 1315 1316 switch (mux_command) { 1317 case SSHMUX_COMMAND_ALIVE_CHECK: 1318 fprintf(stderr, "Master running (pid=%d)\r\n", 1319 control_server_pid); 1320 exit(0); 1321 case SSHMUX_COMMAND_TERMINATE: 1322 fprintf(stderr, "Exit request sent.\r\n"); 1323 exit(0); 1324 case SSHMUX_COMMAND_OPEN: 1325 /* continue below */ 1326 break; 1327 default: 1328 fatal("silly mux_command %d", mux_command); 1329 } 1330 1331 /* SSHMUX_COMMAND_OPEN */ 1332 buffer_put_cstring(&m, term ? term : ""); 1333 buffer_append(&command, "\0", 1); 1334 buffer_put_cstring(&m, buffer_ptr(&command)); 1335 1336 if (options.num_send_env == 0 || environ == NULL) { 1337 buffer_put_int(&m, 0); 1338 } else { 1339 /* Pass environment */ 1340 num_env = 0; 1341 for (i = 0; environ[i] != NULL; i++) 1342 if (env_permitted(environ[i])) 1343 num_env++; /* Count */ 1344 1345 buffer_put_int(&m, num_env); 1346 1347 for (i = 0; environ[i] != NULL && num_env >= 0; i++) 1348 if (env_permitted(environ[i])) { 1349 num_env--; 1350 buffer_put_cstring(&m, environ[i]); 1351 } 1352 } 1353 1354 if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1) 1355 fatal("%s: msg_send", __func__); 1356 1357 mm_send_fd(sock, STDIN_FILENO); 1358 mm_send_fd(sock, STDOUT_FILENO); 1359 mm_send_fd(sock, STDERR_FILENO); 1360 1361 /* Wait for reply, so master has a chance to gather ttymodes */ 1362 buffer_clear(&m); 1363 if (ssh_msg_recv(sock, &m) == -1) 1364 fatal("%s: msg_recv", __func__); 1365 if (buffer_get_char(&m) != SSHMUX_VER) 1366 fatal("%s: wrong version", __func__); 1367 buffer_free(&m); 1368 1369 signal(SIGHUP, control_client_sighandler); 1370 signal(SIGINT, control_client_sighandler); 1371 signal(SIGTERM, control_client_sighandler); 1372 signal(SIGWINCH, control_client_sigrelay); 1373 1374 if (tty_flag) 1375 enter_raw_mode(); 1376 1377 /* Stick around until the controlee closes the client_fd */ 1378 exitval = 0; 1379 for (;!control_client_terminate;) { 1380 r = read(sock, &exitval, sizeof(exitval)); 1381 if (r == 0) { 1382 debug2("Received EOF from master"); 1383 break; 1384 } 1385 if (r > 0) 1386 debug2("Received exit status from master %d", exitval); 1387 if (r == -1 && errno != EINTR) 1388 fatal("%s: read %s", __func__, strerror(errno)); 1389 } 1390 1391 if (control_client_terminate) 1392 debug2("Exiting on signal %d", control_client_terminate); 1393 1394 close(sock); 1395 1396 leave_raw_mode(); 1397 1398 if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET) 1399 fprintf(stderr, "Connection to master closed.\r\n"); 1400 1401 exit(exitval); 1402 } 1403