1 /* $OpenBSD: ssh.c,v 1.324 2009/02/12 03:00:56 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * Ssh client program. This program can be used to log into a remote machine. 7 * The software supports strong authentication, encryption, and forwarding 8 * of X11, TCP/IP, and authentication connections. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * Copyright (c) 1999 Niels Provos. All rights reserved. 17 * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved. 18 * 19 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu> 20 * in Canada (German citizen). 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 32 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 34 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 41 */ 42 43 #include "includes.h" 44 45 #include <sys/types.h> 46 #ifdef HAVE_SYS_STAT_H 47 # include <sys/stat.h> 48 #endif 49 #include <sys/resource.h> 50 #include <sys/ioctl.h> 51 #include <sys/socket.h> 52 53 #include <ctype.h> 54 #include <errno.h> 55 #include <fcntl.h> 56 #include <netdb.h> 57 #ifdef HAVE_PATHS_H 58 #include <paths.h> 59 #endif 60 #include <pwd.h> 61 #include <signal.h> 62 #include <stdarg.h> 63 #include <stddef.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <unistd.h> 68 69 #include <netinet/in.h> 70 #include <arpa/inet.h> 71 72 #include <openssl/evp.h> 73 #include <openssl/err.h> 74 #include "openbsd-compat/openssl-compat.h" 75 #include "openbsd-compat/sys-queue.h" 76 77 #include "xmalloc.h" 78 #include "ssh.h" 79 #include "ssh1.h" 80 #include "ssh2.h" 81 #include "compat.h" 82 #include "cipher.h" 83 #include "packet.h" 84 #include "buffer.h" 85 #include "channels.h" 86 #include "key.h" 87 #include "authfd.h" 88 #include "authfile.h" 89 #include "pathnames.h" 90 #include "dispatch.h" 91 #include "clientloop.h" 92 #include "log.h" 93 #include "readconf.h" 94 #include "sshconnect.h" 95 #include "misc.h" 96 #include "kex.h" 97 #include "mac.h" 98 #include "sshpty.h" 99 #include "match.h" 100 #include "msg.h" 101 #include "uidswap.h" 102 #include "version.h" 103 104 #ifdef SMARTCARD 105 #include "scard.h" 106 #endif 107 108 extern char *__progname; 109 110 /* Flag indicating whether debug mode is on. May be set on the command line. */ 111 int debug_flag = 0; 112 113 /* Flag indicating whether a tty should be allocated */ 114 int tty_flag = 0; 115 int no_tty_flag = 0; 116 int force_tty_flag = 0; 117 118 /* don't exec a shell */ 119 int no_shell_flag = 0; 120 121 /* 122 * Flag indicating that nothing should be read from stdin. This can be set 123 * on the command line. 124 */ 125 int stdin_null_flag = 0; 126 127 /* 128 * Flag indicating that ssh should fork after authentication. This is useful 129 * so that the passphrase can be entered manually, and then ssh goes to the 130 * background. 131 */ 132 int fork_after_authentication_flag = 0; 133 134 /* 135 * General data structure for command line options and options configurable 136 * in configuration files. See readconf.h. 137 */ 138 Options options; 139 140 /* optional user configfile */ 141 char *config = NULL; 142 143 /* 144 * Name of the host we are connecting to. This is the name given on the 145 * command line, or the HostName specified for the user-supplied name in a 146 * configuration file. 147 */ 148 char *host; 149 150 /* socket address the host resolves to */ 151 struct sockaddr_storage hostaddr; 152 153 /* Private host keys. */ 154 Sensitive sensitive_data; 155 156 /* Original real UID. */ 157 uid_t original_real_uid; 158 uid_t original_effective_uid; 159 160 /* command to be executed */ 161 Buffer command; 162 163 /* Should we execute a command or invoke a subsystem? */ 164 int subsystem_flag = 0; 165 166 /* # of replies received for global requests */ 167 static int remote_forward_confirms_received = 0; 168 169 /* pid of proxycommand child process */ 170 pid_t proxy_command_pid = 0; 171 172 /* mux.c */ 173 extern int muxserver_sock; 174 extern u_int muxclient_command; 175 176 /* Prints a help message to the user. This function never returns. */ 177 178 static void 179 usage(void) 180 { 181 fprintf(stderr, 182 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" 183 " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n" 184 " [-i identity_file] [-L [bind_address:]port:host:hostport]\n" 185 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n" 186 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n" 187 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n" 188 ); 189 exit(255); 190 } 191 192 static int ssh_session(void); 193 static int ssh_session2(void); 194 static void load_public_identity_files(void); 195 196 /* from muxclient.c */ 197 void muxclient(const char *); 198 void muxserver_listen(void); 199 200 /* 201 * Main program for the ssh client. 202 */ 203 int 204 main(int ac, char **av) 205 { 206 int i, opt, exit_status, use_syslog; 207 char *p, *cp, *line, buf[256]; 208 struct stat st; 209 struct passwd *pw; 210 int dummy, timeout_ms; 211 extern int optind, optreset; 212 extern char *optarg; 213 struct servent *sp; 214 Forward fwd; 215 216 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 217 sanitise_stdfd(); 218 219 __progname = ssh_get_progname(av[0]); 220 init_rng(); 221 222 /* 223 * Save the original real uid. It will be needed later (uid-swapping 224 * may clobber the real uid). 225 */ 226 original_real_uid = getuid(); 227 original_effective_uid = geteuid(); 228 229 /* 230 * Use uid-swapping to give up root privileges for the duration of 231 * option processing. We will re-instantiate the rights when we are 232 * ready to create the privileged port, and will permanently drop 233 * them when the port has been created (actually, when the connection 234 * has been made, as we may need to create the port several times). 235 */ 236 PRIV_END; 237 238 #ifdef HAVE_SETRLIMIT 239 /* If we are installed setuid root be careful to not drop core. */ 240 if (original_real_uid != original_effective_uid) { 241 struct rlimit rlim; 242 rlim.rlim_cur = rlim.rlim_max = 0; 243 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 244 fatal("setrlimit failed: %.100s", strerror(errno)); 245 } 246 #endif 247 /* Get user data. */ 248 pw = getpwuid(original_real_uid); 249 if (!pw) { 250 logit("You don't exist, go away!"); 251 exit(255); 252 } 253 /* Take a copy of the returned structure. */ 254 pw = pwcopy(pw); 255 256 /* 257 * Set our umask to something reasonable, as some files are created 258 * with the default umask. This will make them world-readable but 259 * writable only by the owner, which is ok for all files for which we 260 * don't set the modes explicitly. 261 */ 262 umask(022); 263 264 /* 265 * Initialize option structure to indicate that no values have been 266 * set. 267 */ 268 initialize_options(&options); 269 270 /* Parse command-line arguments. */ 271 host = NULL; 272 use_syslog = 0; 273 274 again: 275 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 276 "ACD:F:I:KL:MNO:PR:S:TVw:XYy")) != -1) { 277 switch (opt) { 278 case '1': 279 options.protocol = SSH_PROTO_1; 280 break; 281 case '2': 282 options.protocol = SSH_PROTO_2; 283 break; 284 case '4': 285 options.address_family = AF_INET; 286 break; 287 case '6': 288 options.address_family = AF_INET6; 289 break; 290 case 'n': 291 stdin_null_flag = 1; 292 break; 293 case 'f': 294 fork_after_authentication_flag = 1; 295 stdin_null_flag = 1; 296 break; 297 case 'x': 298 options.forward_x11 = 0; 299 break; 300 case 'X': 301 options.forward_x11 = 1; 302 break; 303 case 'y': 304 use_syslog = 1; 305 break; 306 case 'Y': 307 options.forward_x11 = 1; 308 options.forward_x11_trusted = 1; 309 break; 310 case 'g': 311 options.gateway_ports = 1; 312 break; 313 case 'O': 314 if (strcmp(optarg, "check") == 0) 315 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; 316 else if (strcmp(optarg, "exit") == 0) 317 muxclient_command = SSHMUX_COMMAND_TERMINATE; 318 else 319 fatal("Invalid multiplex command."); 320 break; 321 case 'P': /* deprecated */ 322 options.use_privileged_port = 0; 323 break; 324 case 'a': 325 options.forward_agent = 0; 326 break; 327 case 'A': 328 options.forward_agent = 1; 329 break; 330 case 'k': 331 options.gss_deleg_creds = 0; 332 break; 333 case 'K': 334 options.gss_authentication = 1; 335 options.gss_deleg_creds = 1; 336 break; 337 case 'i': 338 if (stat(optarg, &st) < 0) { 339 fprintf(stderr, "Warning: Identity file %s " 340 "not accessible: %s.\n", optarg, 341 strerror(errno)); 342 break; 343 } 344 if (options.num_identity_files >= 345 SSH_MAX_IDENTITY_FILES) 346 fatal("Too many identity files specified " 347 "(max %d)", SSH_MAX_IDENTITY_FILES); 348 options.identity_files[options.num_identity_files++] = 349 xstrdup(optarg); 350 break; 351 case 'I': 352 #ifdef SMARTCARD 353 options.smartcard_device = xstrdup(optarg); 354 #else 355 fprintf(stderr, "no support for smartcards.\n"); 356 #endif 357 break; 358 case 't': 359 if (tty_flag) 360 force_tty_flag = 1; 361 tty_flag = 1; 362 break; 363 case 'v': 364 if (debug_flag == 0) { 365 debug_flag = 1; 366 options.log_level = SYSLOG_LEVEL_DEBUG1; 367 } else { 368 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 369 options.log_level++; 370 break; 371 } 372 /* FALLTHROUGH */ 373 case 'V': 374 fprintf(stderr, "%s, %s\n", 375 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); 376 if (opt == 'V') 377 exit(0); 378 break; 379 case 'w': 380 if (options.tun_open == -1) 381 options.tun_open = SSH_TUNMODE_DEFAULT; 382 options.tun_local = a2tun(optarg, &options.tun_remote); 383 if (options.tun_local == SSH_TUNID_ERR) { 384 fprintf(stderr, 385 "Bad tun device '%s'\n", optarg); 386 exit(255); 387 } 388 break; 389 case 'q': 390 options.log_level = SYSLOG_LEVEL_QUIET; 391 break; 392 case 'e': 393 if (optarg[0] == '^' && optarg[2] == 0 && 394 (u_char) optarg[1] >= 64 && 395 (u_char) optarg[1] < 128) 396 options.escape_char = (u_char) optarg[1] & 31; 397 else if (strlen(optarg) == 1) 398 options.escape_char = (u_char) optarg[0]; 399 else if (strcmp(optarg, "none") == 0) 400 options.escape_char = SSH_ESCAPECHAR_NONE; 401 else { 402 fprintf(stderr, "Bad escape character '%s'.\n", 403 optarg); 404 exit(255); 405 } 406 break; 407 case 'c': 408 if (ciphers_valid(optarg)) { 409 /* SSH2 only */ 410 options.ciphers = xstrdup(optarg); 411 options.cipher = SSH_CIPHER_INVALID; 412 } else { 413 /* SSH1 only */ 414 options.cipher = cipher_number(optarg); 415 if (options.cipher == -1) { 416 fprintf(stderr, 417 "Unknown cipher type '%s'\n", 418 optarg); 419 exit(255); 420 } 421 if (options.cipher == SSH_CIPHER_3DES) 422 options.ciphers = "3des-cbc"; 423 else if (options.cipher == SSH_CIPHER_BLOWFISH) 424 options.ciphers = "blowfish-cbc"; 425 else 426 options.ciphers = (char *)-1; 427 } 428 break; 429 case 'm': 430 if (mac_valid(optarg)) 431 options.macs = xstrdup(optarg); 432 else { 433 fprintf(stderr, "Unknown mac type '%s'\n", 434 optarg); 435 exit(255); 436 } 437 break; 438 case 'M': 439 if (options.control_master == SSHCTL_MASTER_YES) 440 options.control_master = SSHCTL_MASTER_ASK; 441 else 442 options.control_master = SSHCTL_MASTER_YES; 443 break; 444 case 'p': 445 options.port = a2port(optarg); 446 if (options.port <= 0) { 447 fprintf(stderr, "Bad port '%s'\n", optarg); 448 exit(255); 449 } 450 break; 451 case 'l': 452 options.user = optarg; 453 break; 454 455 case 'L': 456 if (parse_forward(&fwd, optarg, 0, 0)) 457 add_local_forward(&options, &fwd); 458 else { 459 fprintf(stderr, 460 "Bad local forwarding specification '%s'\n", 461 optarg); 462 exit(255); 463 } 464 break; 465 466 case 'R': 467 if (parse_forward(&fwd, optarg, 0, 1)) { 468 add_remote_forward(&options, &fwd); 469 } else { 470 fprintf(stderr, 471 "Bad remote forwarding specification " 472 "'%s'\n", optarg); 473 exit(255); 474 } 475 break; 476 477 case 'D': 478 if (parse_forward(&fwd, optarg, 1, 0)) { 479 add_local_forward(&options, &fwd); 480 } else { 481 fprintf(stderr, 482 "Bad dynamic forwarding specification " 483 "'%s'\n", optarg); 484 exit(255); 485 } 486 break; 487 488 case 'C': 489 options.compression = 1; 490 break; 491 case 'N': 492 no_shell_flag = 1; 493 no_tty_flag = 1; 494 break; 495 case 'T': 496 no_tty_flag = 1; 497 break; 498 case 'o': 499 dummy = 1; 500 line = xstrdup(optarg); 501 if (process_config_line(&options, host ? host : "", 502 line, "command-line", 0, &dummy) != 0) 503 exit(255); 504 xfree(line); 505 break; 506 case 's': 507 subsystem_flag = 1; 508 break; 509 case 'S': 510 if (options.control_path != NULL) 511 free(options.control_path); 512 options.control_path = xstrdup(optarg); 513 break; 514 case 'b': 515 options.bind_address = optarg; 516 break; 517 case 'F': 518 config = optarg; 519 break; 520 default: 521 usage(); 522 } 523 } 524 525 ac -= optind; 526 av += optind; 527 528 if (ac > 0 && !host && **av != '-') { 529 if (strrchr(*av, '@')) { 530 p = xstrdup(*av); 531 cp = strrchr(p, '@'); 532 if (cp == NULL || cp == p) 533 usage(); 534 options.user = p; 535 *cp = '\0'; 536 host = ++cp; 537 } else 538 host = *av; 539 if (ac > 1) { 540 optind = optreset = 1; 541 goto again; 542 } 543 ac--, av++; 544 } 545 546 /* Check that we got a host name. */ 547 if (!host) 548 usage(); 549 550 SSLeay_add_all_algorithms(); 551 ERR_load_crypto_strings(); 552 553 /* Initialize the command to execute on remote host. */ 554 buffer_init(&command); 555 556 /* 557 * Save the command to execute on the remote host in a buffer. There 558 * is no limit on the length of the command, except by the maximum 559 * packet size. Also sets the tty flag if there is no command. 560 */ 561 if (!ac) { 562 /* No command specified - execute shell on a tty. */ 563 tty_flag = 1; 564 if (subsystem_flag) { 565 fprintf(stderr, 566 "You must specify a subsystem to invoke.\n"); 567 usage(); 568 } 569 } else { 570 /* A command has been specified. Store it into the buffer. */ 571 for (i = 0; i < ac; i++) { 572 if (i) 573 buffer_append(&command, " ", 1); 574 buffer_append(&command, av[i], strlen(av[i])); 575 } 576 } 577 578 /* Cannot fork to background if no command. */ 579 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 580 !no_shell_flag) 581 fatal("Cannot fork into background without a command " 582 "to execute."); 583 584 /* Allocate a tty by default if no command specified. */ 585 if (buffer_len(&command) == 0) 586 tty_flag = 1; 587 588 /* Force no tty */ 589 if (no_tty_flag) 590 tty_flag = 0; 591 /* Do not allocate a tty if stdin is not a tty. */ 592 if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) { 593 if (tty_flag) 594 logit("Pseudo-terminal will not be allocated because " 595 "stdin is not a terminal."); 596 tty_flag = 0; 597 } 598 599 /* 600 * Initialize "log" output. Since we are the client all output 601 * actually goes to stderr. 602 */ 603 log_init(av[0], 604 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 605 SYSLOG_FACILITY_USER, !use_syslog); 606 607 /* 608 * Read per-user configuration file. Ignore the system wide config 609 * file if the user specifies a config file on the command line. 610 */ 611 if (config != NULL) { 612 if (!read_config_file(config, host, &options, 0)) 613 fatal("Can't open user config file %.100s: " 614 "%.100s", config, strerror(errno)); 615 } else { 616 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, 617 _PATH_SSH_USER_CONFFILE); 618 (void)read_config_file(buf, host, &options, 1); 619 620 /* Read systemwide configuration file after use config. */ 621 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, 622 &options, 0); 623 } 624 625 /* Fill configuration defaults. */ 626 fill_default_options(&options); 627 628 channel_set_af(options.address_family); 629 630 /* reinit */ 631 log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 632 633 seed_rng(); 634 635 if (options.user == NULL) 636 options.user = xstrdup(pw->pw_name); 637 638 /* Get default port if port has not been set. */ 639 if (options.port == 0) { 640 sp = getservbyname(SSH_SERVICE_NAME, "tcp"); 641 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; 642 } 643 644 if (options.local_command != NULL) { 645 char thishost[NI_MAXHOST]; 646 647 if (gethostname(thishost, sizeof(thishost)) == -1) 648 fatal("gethostname: %s", strerror(errno)); 649 snprintf(buf, sizeof(buf), "%d", options.port); 650 debug3("expanding LocalCommand: %s", options.local_command); 651 cp = options.local_command; 652 options.local_command = percent_expand(cp, "d", pw->pw_dir, 653 "h", options.hostname? options.hostname : host, 654 "l", thishost, "n", host, "r", options.user, "p", buf, 655 "u", pw->pw_name, (char *)NULL); 656 debug3("expanded LocalCommand: %s", options.local_command); 657 xfree(cp); 658 } 659 660 if (options.hostname != NULL) 661 host = options.hostname; 662 663 /* Find canonic host name. */ 664 if (strchr(host, '.') == 0) { 665 struct addrinfo hints; 666 struct addrinfo *ai = NULL; 667 int errgai; 668 memset(&hints, 0, sizeof(hints)); 669 hints.ai_family = options.address_family; 670 hints.ai_flags = AI_CANONNAME; 671 hints.ai_socktype = SOCK_STREAM; 672 errgai = getaddrinfo(host, NULL, &hints, &ai); 673 if (errgai == 0) { 674 if (ai->ai_canonname != NULL) 675 host = xstrdup(ai->ai_canonname); 676 freeaddrinfo(ai); 677 } 678 } 679 680 /* force lowercase for hostkey matching */ 681 if (options.host_key_alias != NULL) { 682 for (p = options.host_key_alias; *p; p++) 683 if (isupper(*p)) 684 *p = (char)tolower(*p); 685 } 686 687 if (options.proxy_command != NULL && 688 strcmp(options.proxy_command, "none") == 0) { 689 xfree(options.proxy_command); 690 options.proxy_command = NULL; 691 } 692 if (options.control_path != NULL && 693 strcmp(options.control_path, "none") == 0) { 694 xfree(options.control_path); 695 options.control_path = NULL; 696 } 697 698 if (options.control_path != NULL) { 699 char thishost[NI_MAXHOST]; 700 701 if (gethostname(thishost, sizeof(thishost)) == -1) 702 fatal("gethostname: %s", strerror(errno)); 703 snprintf(buf, sizeof(buf), "%d", options.port); 704 cp = tilde_expand_filename(options.control_path, 705 original_real_uid); 706 xfree(options.control_path); 707 options.control_path = percent_expand(cp, "p", buf, "h", host, 708 "r", options.user, "l", thishost, (char *)NULL); 709 xfree(cp); 710 } 711 if (muxclient_command != 0 && options.control_path == NULL) 712 fatal("No ControlPath specified for \"-O\" command"); 713 if (options.control_path != NULL) 714 muxclient(options.control_path); 715 716 timeout_ms = options.connection_timeout * 1000; 717 718 /* Open a connection to the remote host. */ 719 if (ssh_connect(host, &hostaddr, options.port, 720 options.address_family, options.connection_attempts, &timeout_ms, 721 options.tcp_keep_alive, 722 #ifdef HAVE_CYGWIN 723 options.use_privileged_port, 724 #else 725 original_effective_uid == 0 && options.use_privileged_port, 726 #endif 727 options.proxy_command) != 0) 728 exit(255); 729 730 if (timeout_ms > 0) 731 debug3("timeout: %d ms remain after connect", timeout_ms); 732 733 /* 734 * If we successfully made the connection, load the host private key 735 * in case we will need it later for combined rsa-rhosts 736 * authentication. This must be done before releasing extra 737 * privileges, because the file is only readable by root. 738 * If we cannot access the private keys, load the public keys 739 * instead and try to execute the ssh-keysign helper instead. 740 */ 741 sensitive_data.nkeys = 0; 742 sensitive_data.keys = NULL; 743 sensitive_data.external_keysign = 0; 744 if (options.rhosts_rsa_authentication || 745 options.hostbased_authentication) { 746 sensitive_data.nkeys = 3; 747 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 748 sizeof(Key)); 749 750 PRIV_START; 751 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 752 _PATH_HOST_KEY_FILE, "", NULL, NULL); 753 sensitive_data.keys[1] = key_load_private_type(KEY_DSA, 754 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 755 sensitive_data.keys[2] = key_load_private_type(KEY_RSA, 756 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 757 PRIV_END; 758 759 if (options.hostbased_authentication == 1 && 760 sensitive_data.keys[0] == NULL && 761 sensitive_data.keys[1] == NULL && 762 sensitive_data.keys[2] == NULL) { 763 sensitive_data.keys[1] = key_load_public( 764 _PATH_HOST_DSA_KEY_FILE, NULL); 765 sensitive_data.keys[2] = key_load_public( 766 _PATH_HOST_RSA_KEY_FILE, NULL); 767 sensitive_data.external_keysign = 1; 768 } 769 } 770 /* 771 * Get rid of any extra privileges that we may have. We will no 772 * longer need them. Also, extra privileges could make it very hard 773 * to read identity files and other non-world-readable files from the 774 * user's home directory if it happens to be on a NFS volume where 775 * root is mapped to nobody. 776 */ 777 if (original_effective_uid == 0) { 778 PRIV_START; 779 permanently_set_uid(pw); 780 } 781 782 /* 783 * Now that we are back to our own permissions, create ~/.ssh 784 * directory if it doesn't already exist. 785 */ 786 snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, 787 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 788 if (stat(buf, &st) < 0) 789 if (mkdir(buf, 0700) < 0) 790 error("Could not create directory '%.200s'.", buf); 791 792 /* load options.identity_files */ 793 load_public_identity_files(); 794 795 /* Expand ~ in known host file names. */ 796 /* XXX mem-leaks: */ 797 options.system_hostfile = 798 tilde_expand_filename(options.system_hostfile, original_real_uid); 799 options.user_hostfile = 800 tilde_expand_filename(options.user_hostfile, original_real_uid); 801 options.system_hostfile2 = 802 tilde_expand_filename(options.system_hostfile2, original_real_uid); 803 options.user_hostfile2 = 804 tilde_expand_filename(options.user_hostfile2, original_real_uid); 805 806 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 807 808 /* Log into the remote system. Never returns if the login fails. */ 809 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 810 pw, timeout_ms); 811 812 /* We no longer need the private host keys. Clear them now. */ 813 if (sensitive_data.nkeys != 0) { 814 for (i = 0; i < sensitive_data.nkeys; i++) { 815 if (sensitive_data.keys[i] != NULL) { 816 /* Destroys contents safely */ 817 debug3("clear hostkey %d", i); 818 key_free(sensitive_data.keys[i]); 819 sensitive_data.keys[i] = NULL; 820 } 821 } 822 xfree(sensitive_data.keys); 823 } 824 for (i = 0; i < options.num_identity_files; i++) { 825 if (options.identity_files[i]) { 826 xfree(options.identity_files[i]); 827 options.identity_files[i] = NULL; 828 } 829 if (options.identity_keys[i]) { 830 key_free(options.identity_keys[i]); 831 options.identity_keys[i] = NULL; 832 } 833 } 834 835 exit_status = compat20 ? ssh_session2() : ssh_session(); 836 packet_close(); 837 838 if (options.control_path != NULL && muxserver_sock != -1) 839 unlink(options.control_path); 840 841 /* 842 * Send SIGHUP to proxy command if used. We don't wait() in 843 * case it hangs and instead rely on init to reap the child 844 */ 845 if (proxy_command_pid > 1) 846 kill(proxy_command_pid, SIGHUP); 847 848 return exit_status; 849 } 850 851 /* Callback for remote forward global requests */ 852 static void 853 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 854 { 855 Forward *rfwd = (Forward *)ctxt; 856 857 /* XXX verbose() on failure? */ 858 debug("remote forward %s for: listen %d, connect %s:%d", 859 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 860 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 861 if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) { 862 logit("Allocated port %u for remote forward to %s:%d", 863 packet_get_int(), 864 rfwd->connect_host, rfwd->connect_port); 865 } 866 867 if (type == SSH2_MSG_REQUEST_FAILURE) { 868 if (options.exit_on_forward_failure) 869 fatal("Error: remote port forwarding failed for " 870 "listen port %d", rfwd->listen_port); 871 else 872 logit("Warning: remote port forwarding failed for " 873 "listen port %d", rfwd->listen_port); 874 } 875 if (++remote_forward_confirms_received == options.num_remote_forwards) { 876 debug("All remote forwarding requests processed"); 877 if (fork_after_authentication_flag) { 878 fork_after_authentication_flag = 0; 879 if (daemon(1, 1) < 0) 880 fatal("daemon() failed: %.200s", 881 strerror(errno)); 882 } 883 } 884 } 885 886 static void 887 ssh_init_forwarding(void) 888 { 889 int success = 0; 890 int i; 891 892 /* Initiate local TCP/IP port forwardings. */ 893 for (i = 0; i < options.num_local_forwards; i++) { 894 debug("Local connections to %.200s:%d forwarded to remote " 895 "address %.200s:%d", 896 (options.local_forwards[i].listen_host == NULL) ? 897 (options.gateway_ports ? "*" : "LOCALHOST") : 898 options.local_forwards[i].listen_host, 899 options.local_forwards[i].listen_port, 900 options.local_forwards[i].connect_host, 901 options.local_forwards[i].connect_port); 902 success += channel_setup_local_fwd_listener( 903 options.local_forwards[i].listen_host, 904 options.local_forwards[i].listen_port, 905 options.local_forwards[i].connect_host, 906 options.local_forwards[i].connect_port, 907 options.gateway_ports); 908 } 909 if (i > 0 && success != i && options.exit_on_forward_failure) 910 fatal("Could not request local forwarding."); 911 if (i > 0 && success == 0) 912 error("Could not request local forwarding."); 913 914 /* Initiate remote TCP/IP port forwardings. */ 915 for (i = 0; i < options.num_remote_forwards; i++) { 916 debug("Remote connections from %.200s:%d forwarded to " 917 "local address %.200s:%d", 918 (options.remote_forwards[i].listen_host == NULL) ? 919 "LOCALHOST" : options.remote_forwards[i].listen_host, 920 options.remote_forwards[i].listen_port, 921 options.remote_forwards[i].connect_host, 922 options.remote_forwards[i].connect_port); 923 if (channel_request_remote_forwarding( 924 options.remote_forwards[i].listen_host, 925 options.remote_forwards[i].listen_port, 926 options.remote_forwards[i].connect_host, 927 options.remote_forwards[i].connect_port) < 0) { 928 if (options.exit_on_forward_failure) 929 fatal("Could not request remote forwarding."); 930 else 931 logit("Warning: Could not request remote " 932 "forwarding."); 933 } 934 client_register_global_confirm(ssh_confirm_remote_forward, 935 &options.remote_forwards[i]); 936 } 937 938 /* Initiate tunnel forwarding. */ 939 if (options.tun_open != SSH_TUNMODE_NO) { 940 if (client_request_tun_fwd(options.tun_open, 941 options.tun_local, options.tun_remote) == -1) { 942 if (options.exit_on_forward_failure) 943 fatal("Could not request tunnel forwarding."); 944 else 945 error("Could not request tunnel forwarding."); 946 } 947 } 948 } 949 950 static void 951 check_agent_present(void) 952 { 953 if (options.forward_agent) { 954 /* Clear agent forwarding if we don't have an agent. */ 955 if (!ssh_agent_present()) 956 options.forward_agent = 0; 957 } 958 } 959 960 static int 961 ssh_session(void) 962 { 963 int type; 964 int interactive = 0; 965 int have_tty = 0; 966 struct winsize ws; 967 char *cp; 968 const char *display; 969 970 /* Enable compression if requested. */ 971 if (options.compression) { 972 debug("Requesting compression at level %d.", 973 options.compression_level); 974 975 if (options.compression_level < 1 || 976 options.compression_level > 9) 977 fatal("Compression level must be from 1 (fast) to " 978 "9 (slow, best)."); 979 980 /* Send the request. */ 981 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 982 packet_put_int(options.compression_level); 983 packet_send(); 984 packet_write_wait(); 985 type = packet_read(); 986 if (type == SSH_SMSG_SUCCESS) 987 packet_start_compression(options.compression_level); 988 else if (type == SSH_SMSG_FAILURE) 989 logit("Warning: Remote host refused compression."); 990 else 991 packet_disconnect("Protocol error waiting for " 992 "compression response."); 993 } 994 /* Allocate a pseudo tty if appropriate. */ 995 if (tty_flag) { 996 debug("Requesting pty."); 997 998 /* Start the packet. */ 999 packet_start(SSH_CMSG_REQUEST_PTY); 1000 1001 /* Store TERM in the packet. There is no limit on the 1002 length of the string. */ 1003 cp = getenv("TERM"); 1004 if (!cp) 1005 cp = ""; 1006 packet_put_cstring(cp); 1007 1008 /* Store window size in the packet. */ 1009 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1010 memset(&ws, 0, sizeof(ws)); 1011 packet_put_int((u_int)ws.ws_row); 1012 packet_put_int((u_int)ws.ws_col); 1013 packet_put_int((u_int)ws.ws_xpixel); 1014 packet_put_int((u_int)ws.ws_ypixel); 1015 1016 /* Store tty modes in the packet. */ 1017 tty_make_modes(fileno(stdin), NULL); 1018 1019 /* Send the packet, and wait for it to leave. */ 1020 packet_send(); 1021 packet_write_wait(); 1022 1023 /* Read response from the server. */ 1024 type = packet_read(); 1025 if (type == SSH_SMSG_SUCCESS) { 1026 interactive = 1; 1027 have_tty = 1; 1028 } else if (type == SSH_SMSG_FAILURE) 1029 logit("Warning: Remote host failed or refused to " 1030 "allocate a pseudo tty."); 1031 else 1032 packet_disconnect("Protocol error waiting for pty " 1033 "request response."); 1034 } 1035 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1036 display = getenv("DISPLAY"); 1037 if (options.forward_x11 && display != NULL) { 1038 char *proto, *data; 1039 /* Get reasonable local authentication information. */ 1040 client_x11_get_proto(display, options.xauth_location, 1041 options.forward_x11_trusted, &proto, &data); 1042 /* Request forwarding with authentication spoofing. */ 1043 debug("Requesting X11 forwarding with authentication " 1044 "spoofing."); 1045 x11_request_forwarding_with_spoofing(0, display, proto, data); 1046 1047 /* Read response from the server. */ 1048 type = packet_read(); 1049 if (type == SSH_SMSG_SUCCESS) { 1050 interactive = 1; 1051 } else if (type == SSH_SMSG_FAILURE) { 1052 logit("Warning: Remote host denied X11 forwarding."); 1053 } else { 1054 packet_disconnect("Protocol error waiting for X11 " 1055 "forwarding"); 1056 } 1057 } 1058 /* Tell the packet module whether this is an interactive session. */ 1059 packet_set_interactive(interactive); 1060 1061 /* Request authentication agent forwarding if appropriate. */ 1062 check_agent_present(); 1063 1064 if (options.forward_agent) { 1065 debug("Requesting authentication agent forwarding."); 1066 auth_request_forwarding(); 1067 1068 /* Read response from the server. */ 1069 type = packet_read(); 1070 packet_check_eom(); 1071 if (type != SSH_SMSG_SUCCESS) 1072 logit("Warning: Remote host denied authentication agent forwarding."); 1073 } 1074 1075 /* Initiate port forwardings. */ 1076 ssh_init_forwarding(); 1077 1078 /* Execute a local command */ 1079 if (options.local_command != NULL && 1080 options.permit_local_command) 1081 ssh_local_cmd(options.local_command); 1082 1083 /* 1084 * If requested and we are not interested in replies to remote 1085 * forwarding requests, then let ssh continue in the background. 1086 */ 1087 if (fork_after_authentication_flag && 1088 (!options.exit_on_forward_failure || 1089 options.num_remote_forwards == 0)) { 1090 fork_after_authentication_flag = 0; 1091 if (daemon(1, 1) < 0) 1092 fatal("daemon() failed: %.200s", strerror(errno)); 1093 } 1094 1095 /* 1096 * If a command was specified on the command line, execute the 1097 * command now. Otherwise request the server to start a shell. 1098 */ 1099 if (buffer_len(&command) > 0) { 1100 int len = buffer_len(&command); 1101 if (len > 900) 1102 len = 900; 1103 debug("Sending command: %.*s", len, 1104 (u_char *)buffer_ptr(&command)); 1105 packet_start(SSH_CMSG_EXEC_CMD); 1106 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1107 packet_send(); 1108 packet_write_wait(); 1109 } else { 1110 debug("Requesting shell."); 1111 packet_start(SSH_CMSG_EXEC_SHELL); 1112 packet_send(); 1113 packet_write_wait(); 1114 } 1115 1116 /* Enter the interactive session. */ 1117 return client_loop(have_tty, tty_flag ? 1118 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1119 } 1120 1121 /* request pty/x11/agent/tcpfwd/shell for channel */ 1122 static void 1123 ssh_session2_setup(int id, void *arg) 1124 { 1125 extern char **environ; 1126 const char *display; 1127 int interactive = tty_flag; 1128 1129 display = getenv("DISPLAY"); 1130 if (options.forward_x11 && display != NULL) { 1131 char *proto, *data; 1132 /* Get reasonable local authentication information. */ 1133 client_x11_get_proto(display, options.xauth_location, 1134 options.forward_x11_trusted, &proto, &data); 1135 /* Request forwarding with authentication spoofing. */ 1136 debug("Requesting X11 forwarding with authentication " 1137 "spoofing."); 1138 x11_request_forwarding_with_spoofing(id, display, proto, data); 1139 interactive = 1; 1140 /* XXX wait for reply */ 1141 } 1142 1143 check_agent_present(); 1144 if (options.forward_agent) { 1145 debug("Requesting authentication agent forwarding."); 1146 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1147 packet_send(); 1148 } 1149 1150 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1151 NULL, fileno(stdin), &command, environ); 1152 1153 packet_set_interactive(interactive); 1154 } 1155 1156 /* open new channel for a session */ 1157 static int 1158 ssh_session2_open(void) 1159 { 1160 Channel *c; 1161 int window, packetmax, in, out, err; 1162 1163 if (stdin_null_flag) { 1164 in = open(_PATH_DEVNULL, O_RDONLY); 1165 } else { 1166 in = dup(STDIN_FILENO); 1167 } 1168 out = dup(STDOUT_FILENO); 1169 err = dup(STDERR_FILENO); 1170 1171 if (in < 0 || out < 0 || err < 0) 1172 fatal("dup() in/out/err failed"); 1173 1174 /* enable nonblocking unless tty */ 1175 if (!isatty(in)) 1176 set_nonblock(in); 1177 if (!isatty(out)) 1178 set_nonblock(out); 1179 if (!isatty(err)) 1180 set_nonblock(err); 1181 1182 window = CHAN_SES_WINDOW_DEFAULT; 1183 packetmax = CHAN_SES_PACKET_DEFAULT; 1184 if (tty_flag) { 1185 window >>= 1; 1186 packetmax >>= 1; 1187 } 1188 c = channel_new( 1189 "session", SSH_CHANNEL_OPENING, in, out, err, 1190 window, packetmax, CHAN_EXTENDED_WRITE, 1191 "client-session", /*nonblock*/0); 1192 1193 debug3("ssh_session2_open: channel_new: %d", c->self); 1194 1195 channel_send_open(c->self); 1196 if (!no_shell_flag) 1197 channel_register_open_confirm(c->self, 1198 ssh_session2_setup, NULL); 1199 1200 return c->self; 1201 } 1202 1203 static int 1204 ssh_session2(void) 1205 { 1206 int id = -1; 1207 1208 /* XXX should be pre-session */ 1209 ssh_init_forwarding(); 1210 1211 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1212 id = ssh_session2_open(); 1213 1214 /* If we don't expect to open a new session, then disallow it */ 1215 if (options.control_master == SSHCTL_MASTER_NO && 1216 (datafellows & SSH_NEW_OPENSSH)) { 1217 debug("Requesting no-more-sessions@openssh.com"); 1218 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1219 packet_put_cstring("no-more-sessions@openssh.com"); 1220 packet_put_char(0); 1221 packet_send(); 1222 } 1223 1224 /* Execute a local command */ 1225 if (options.local_command != NULL && 1226 options.permit_local_command) 1227 ssh_local_cmd(options.local_command); 1228 1229 /* Start listening for multiplex clients */ 1230 muxserver_listen(); 1231 1232 /* If requested, let ssh continue in the background. */ 1233 if (fork_after_authentication_flag) { 1234 fork_after_authentication_flag = 0; 1235 if (daemon(1, 1) < 0) 1236 fatal("daemon() failed: %.200s", strerror(errno)); 1237 } 1238 1239 return client_loop(tty_flag, tty_flag ? 1240 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1241 } 1242 1243 static void 1244 load_public_identity_files(void) 1245 { 1246 char *filename, *cp, thishost[NI_MAXHOST]; 1247 char *pwdir = NULL, *pwname = NULL; 1248 int i = 0; 1249 Key *public; 1250 struct passwd *pw; 1251 #ifdef SMARTCARD 1252 Key **keys; 1253 1254 if (options.smartcard_device != NULL && 1255 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1256 (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) { 1257 int count = 0; 1258 for (i = 0; keys[i] != NULL; i++) { 1259 count++; 1260 memmove(&options.identity_files[1], 1261 &options.identity_files[0], 1262 sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1)); 1263 memmove(&options.identity_keys[1], 1264 &options.identity_keys[0], 1265 sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1)); 1266 options.num_identity_files++; 1267 options.identity_keys[0] = keys[i]; 1268 options.identity_files[0] = sc_get_key_label(keys[i]); 1269 } 1270 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES) 1271 options.num_identity_files = SSH_MAX_IDENTITY_FILES; 1272 i = count; 1273 xfree(keys); 1274 } 1275 #endif /* SMARTCARD */ 1276 if ((pw = getpwuid(original_real_uid)) == NULL) 1277 fatal("load_public_identity_files: getpwuid failed"); 1278 pwname = xstrdup(pw->pw_name); 1279 pwdir = xstrdup(pw->pw_dir); 1280 if (gethostname(thishost, sizeof(thishost)) == -1) 1281 fatal("load_public_identity_files: gethostname: %s", 1282 strerror(errno)); 1283 for (; i < options.num_identity_files; i++) { 1284 cp = tilde_expand_filename(options.identity_files[i], 1285 original_real_uid); 1286 filename = percent_expand(cp, "d", pwdir, 1287 "u", pwname, "l", thishost, "h", host, 1288 "r", options.user, (char *)NULL); 1289 xfree(cp); 1290 public = key_load_public(filename, NULL); 1291 debug("identity file %s type %d", filename, 1292 public ? public->type : -1); 1293 xfree(options.identity_files[i]); 1294 options.identity_files[i] = filename; 1295 options.identity_keys[i] = public; 1296 } 1297 bzero(pwname, strlen(pwname)); 1298 xfree(pwname); 1299 bzero(pwdir, strlen(pwdir)); 1300 xfree(pwdir); 1301 } 1302