1 /* $OpenBSD: ssh.c,v 1.327 2009/10/24 11:23:42 andreas 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 <sys/types.h> 44 #include <sys/ioctl.h> 45 #include <sys/param.h> 46 #include <sys/queue.h> 47 #include <sys/resource.h> 48 #include <sys/socket.h> 49 #include <sys/stat.h> 50 #include <sys/types.h> 51 #include <sys/time.h> 52 53 #include <ctype.h> 54 #include <errno.h> 55 #include <fcntl.h> 56 #include <netdb.h> 57 #include <paths.h> 58 #include <pwd.h> 59 #include <signal.h> 60 #include <stddef.h> 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <string.h> 64 #include <unistd.h> 65 66 #include <openssl/evp.h> 67 #include <openssl/err.h> 68 69 #include "xmalloc.h" 70 #include "ssh.h" 71 #include "ssh1.h" 72 #include "ssh2.h" 73 #include "compat.h" 74 #include "cipher.h" 75 #include "packet.h" 76 #include "buffer.h" 77 #include "channels.h" 78 #include "key.h" 79 #include "authfd.h" 80 #include "authfile.h" 81 #include "pathnames.h" 82 #include "dispatch.h" 83 #include "clientloop.h" 84 #include "log.h" 85 #include "readconf.h" 86 #include "sshconnect.h" 87 #include "misc.h" 88 #include "kex.h" 89 #include "mac.h" 90 #include "sshpty.h" 91 #include "match.h" 92 #include "msg.h" 93 #include "uidswap.h" 94 #include "roaming.h" 95 #include "version.h" 96 97 #ifdef SMARTCARD 98 #include "scard.h" 99 #endif 100 101 extern char *__progname; 102 103 /* Flag indicating whether debug mode is on. May be set on the command line. */ 104 int debug_flag = 0; 105 106 /* Flag indicating whether a tty should be allocated */ 107 int tty_flag = 0; 108 int no_tty_flag = 0; 109 int force_tty_flag = 0; 110 111 /* don't exec a shell */ 112 int no_shell_flag = 0; 113 114 /* 115 * Flag indicating that nothing should be read from stdin. This can be set 116 * on the command line. 117 */ 118 int stdin_null_flag = 0; 119 120 /* 121 * Flag indicating that ssh should fork after authentication. This is useful 122 * so that the passphrase can be entered manually, and then ssh goes to the 123 * background. 124 */ 125 int fork_after_authentication_flag = 0; 126 127 /* 128 * General data structure for command line options and options configurable 129 * in configuration files. See readconf.h. 130 */ 131 Options options; 132 133 /* optional user configfile */ 134 char *config = NULL; 135 136 /* 137 * Name of the host we are connecting to. This is the name given on the 138 * command line, or the HostName specified for the user-supplied name in a 139 * configuration file. 140 */ 141 char *host; 142 143 /* socket address the host resolves to */ 144 struct sockaddr_storage hostaddr; 145 146 /* Private host keys. */ 147 Sensitive sensitive_data; 148 149 /* Original real UID. */ 150 uid_t original_real_uid; 151 uid_t original_effective_uid; 152 153 /* command to be executed */ 154 Buffer command; 155 156 /* Should we execute a command or invoke a subsystem? */ 157 int subsystem_flag = 0; 158 159 /* # of replies received for global requests */ 160 static int remote_forward_confirms_received = 0; 161 162 /* pid of proxycommand child process */ 163 pid_t proxy_command_pid = 0; 164 165 /* mux.c */ 166 extern int muxserver_sock; 167 extern u_int muxclient_command; 168 169 170 /* Prints a help message to the user. This function never returns. */ 171 172 static void 173 usage(void) 174 { 175 fprintf(stderr, 176 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" 177 " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n" 178 " [-i identity_file] [-L [bind_address:]port:host:hostport]\n" 179 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n" 180 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n" 181 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n" 182 ); 183 exit(255); 184 } 185 186 static int ssh_session(void); 187 static int ssh_session2(void); 188 static void load_public_identity_files(void); 189 190 /* from muxclient.c */ 191 void muxclient(const char *); 192 void muxserver_listen(void); 193 194 /* 195 * Main program for the ssh client. 196 */ 197 int 198 main(int ac, char **av) 199 { 200 int i, r, opt, exit_status, use_syslog; 201 char *p, *cp, *line, *argv0, buf[MAXPATHLEN]; 202 struct stat st; 203 struct passwd *pw; 204 int dummy, timeout_ms; 205 extern int optind, optreset; 206 extern char *optarg; 207 struct servent *sp; 208 Forward fwd; 209 210 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 211 sanitise_stdfd(); 212 213 /* 214 * Save the original real uid. It will be needed later (uid-swapping 215 * may clobber the real uid). 216 */ 217 original_real_uid = getuid(); 218 original_effective_uid = geteuid(); 219 220 /* 221 * Use uid-swapping to give up root privileges for the duration of 222 * option processing. We will re-instantiate the rights when we are 223 * ready to create the privileged port, and will permanently drop 224 * them when the port has been created (actually, when the connection 225 * has been made, as we may need to create the port several times). 226 */ 227 PRIV_END; 228 229 /* If we are installed setuid root be careful to not drop core. */ 230 if (original_real_uid != original_effective_uid) { 231 struct rlimit rlim; 232 rlim.rlim_cur = rlim.rlim_max = 0; 233 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 234 fatal("setrlimit failed: %.100s", strerror(errno)); 235 } 236 /* Get user data. */ 237 pw = getpwuid(original_real_uid); 238 if (!pw) { 239 logit("You don't exist, go away!"); 240 exit(255); 241 } 242 /* Take a copy of the returned structure. */ 243 pw = pwcopy(pw); 244 245 /* 246 * Set our umask to something reasonable, as some files are created 247 * with the default umask. This will make them world-readable but 248 * writable only by the owner, which is ok for all files for which we 249 * don't set the modes explicitly. 250 */ 251 umask(022); 252 253 /* 254 * Initialize option structure to indicate that no values have been 255 * set. 256 */ 257 initialize_options(&options); 258 259 /* Parse command-line arguments. */ 260 host = NULL; 261 use_syslog = 0; 262 argv0 = av[0]; 263 264 again: 265 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 266 "ACD:F:I:KL:MNO:PR:S:TVw:XYy")) != -1) { 267 switch (opt) { 268 case '1': 269 options.protocol = SSH_PROTO_1; 270 break; 271 case '2': 272 options.protocol = SSH_PROTO_2; 273 break; 274 case '4': 275 options.address_family = AF_INET; 276 break; 277 case '6': 278 options.address_family = AF_INET6; 279 break; 280 case 'n': 281 stdin_null_flag = 1; 282 break; 283 case 'f': 284 fork_after_authentication_flag = 1; 285 stdin_null_flag = 1; 286 break; 287 case 'x': 288 options.forward_x11 = 0; 289 break; 290 case 'X': 291 options.forward_x11 = 1; 292 break; 293 case 'y': 294 use_syslog = 1; 295 break; 296 case 'Y': 297 options.forward_x11 = 1; 298 options.forward_x11_trusted = 1; 299 break; 300 case 'g': 301 options.gateway_ports = 1; 302 break; 303 case 'O': 304 if (strcmp(optarg, "check") == 0) 305 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; 306 else if (strcmp(optarg, "exit") == 0) 307 muxclient_command = SSHMUX_COMMAND_TERMINATE; 308 else 309 fatal("Invalid multiplex command."); 310 break; 311 case 'P': /* deprecated */ 312 options.use_privileged_port = 0; 313 break; 314 case 'a': 315 options.forward_agent = 0; 316 break; 317 case 'A': 318 options.forward_agent = 1; 319 break; 320 case 'k': 321 options.gss_deleg_creds = 0; 322 break; 323 case 'K': 324 options.gss_authentication = 1; 325 options.gss_deleg_creds = 1; 326 break; 327 case 'i': 328 if (stat(optarg, &st) < 0) { 329 fprintf(stderr, "Warning: Identity file %s " 330 "not accessible: %s.\n", optarg, 331 strerror(errno)); 332 break; 333 } 334 if (options.num_identity_files >= 335 SSH_MAX_IDENTITY_FILES) 336 fatal("Too many identity files specified " 337 "(max %d)", SSH_MAX_IDENTITY_FILES); 338 options.identity_files[options.num_identity_files++] = 339 xstrdup(optarg); 340 break; 341 case 'I': 342 #ifdef SMARTCARD 343 options.smartcard_device = xstrdup(optarg); 344 #else 345 fprintf(stderr, "no support for smartcards.\n"); 346 #endif 347 break; 348 case 't': 349 if (tty_flag) 350 force_tty_flag = 1; 351 tty_flag = 1; 352 break; 353 case 'v': 354 if (debug_flag == 0) { 355 debug_flag = 1; 356 options.log_level = SYSLOG_LEVEL_DEBUG1; 357 } else { 358 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 359 options.log_level++; 360 break; 361 } 362 /* FALLTHROUGH */ 363 case 'V': 364 fprintf(stderr, "%s, %s\n", 365 SSH_VERSION, SSLeay_version(SSLEAY_VERSION)); 366 if (opt == 'V') 367 exit(0); 368 break; 369 case 'w': 370 if (options.tun_open == -1) 371 options.tun_open = SSH_TUNMODE_DEFAULT; 372 options.tun_local = a2tun(optarg, &options.tun_remote); 373 if (options.tun_local == SSH_TUNID_ERR) { 374 fprintf(stderr, 375 "Bad tun device '%s'\n", optarg); 376 exit(255); 377 } 378 break; 379 case 'q': 380 options.log_level = SYSLOG_LEVEL_QUIET; 381 break; 382 case 'e': 383 if (optarg[0] == '^' && optarg[2] == 0 && 384 (u_char) optarg[1] >= 64 && 385 (u_char) optarg[1] < 128) 386 options.escape_char = (u_char) optarg[1] & 31; 387 else if (strlen(optarg) == 1) 388 options.escape_char = (u_char) optarg[0]; 389 else if (strcmp(optarg, "none") == 0) 390 options.escape_char = SSH_ESCAPECHAR_NONE; 391 else { 392 fprintf(stderr, "Bad escape character '%s'.\n", 393 optarg); 394 exit(255); 395 } 396 break; 397 case 'c': 398 if (ciphers_valid(optarg)) { 399 /* SSH2 only */ 400 options.ciphers = xstrdup(optarg); 401 options.cipher = SSH_CIPHER_INVALID; 402 } else { 403 /* SSH1 only */ 404 options.cipher = cipher_number(optarg); 405 if (options.cipher == -1) { 406 fprintf(stderr, 407 "Unknown cipher type '%s'\n", 408 optarg); 409 exit(255); 410 } 411 if (options.cipher == SSH_CIPHER_3DES) 412 options.ciphers = "3des-cbc"; 413 else if (options.cipher == SSH_CIPHER_BLOWFISH) 414 options.ciphers = "blowfish-cbc"; 415 else 416 options.ciphers = (char *)-1; 417 } 418 break; 419 case 'm': 420 if (mac_valid(optarg)) 421 options.macs = xstrdup(optarg); 422 else { 423 fprintf(stderr, "Unknown mac type '%s'\n", 424 optarg); 425 exit(255); 426 } 427 break; 428 case 'M': 429 if (options.control_master == SSHCTL_MASTER_YES) 430 options.control_master = SSHCTL_MASTER_ASK; 431 else 432 options.control_master = SSHCTL_MASTER_YES; 433 break; 434 case 'p': 435 options.port = a2port(optarg); 436 if (options.port <= 0) { 437 fprintf(stderr, "Bad port '%s'\n", optarg); 438 exit(255); 439 } 440 break; 441 case 'l': 442 options.user = optarg; 443 break; 444 445 case 'L': 446 if (parse_forward(&fwd, optarg, 0, 0)) 447 add_local_forward(&options, &fwd); 448 else { 449 fprintf(stderr, 450 "Bad local forwarding specification '%s'\n", 451 optarg); 452 exit(255); 453 } 454 break; 455 456 case 'R': 457 if (parse_forward(&fwd, optarg, 0, 1)) { 458 add_remote_forward(&options, &fwd); 459 } else { 460 fprintf(stderr, 461 "Bad remote forwarding specification " 462 "'%s'\n", optarg); 463 exit(255); 464 } 465 break; 466 467 case 'D': 468 if (parse_forward(&fwd, optarg, 1, 0)) { 469 add_local_forward(&options, &fwd); 470 } else { 471 fprintf(stderr, 472 "Bad dynamic forwarding specification " 473 "'%s'\n", optarg); 474 exit(255); 475 } 476 break; 477 478 case 'C': 479 options.compression = 1; 480 break; 481 case 'N': 482 no_shell_flag = 1; 483 no_tty_flag = 1; 484 break; 485 case 'T': 486 no_tty_flag = 1; 487 break; 488 case 'o': 489 dummy = 1; 490 line = xstrdup(optarg); 491 if (process_config_line(&options, host ? host : "", 492 line, "command-line", 0, &dummy) != 0) 493 exit(255); 494 xfree(line); 495 break; 496 case 's': 497 subsystem_flag = 1; 498 break; 499 case 'S': 500 if (options.control_path != NULL) 501 free(options.control_path); 502 options.control_path = xstrdup(optarg); 503 break; 504 case 'b': 505 options.bind_address = optarg; 506 break; 507 case 'F': 508 config = optarg; 509 break; 510 default: 511 usage(); 512 } 513 } 514 515 ac -= optind; 516 av += optind; 517 518 if (ac > 0 && !host && **av != '-') { 519 if (strrchr(*av, '@')) { 520 p = xstrdup(*av); 521 cp = strrchr(p, '@'); 522 if (cp == NULL || cp == p) 523 usage(); 524 options.user = p; 525 *cp = '\0'; 526 host = ++cp; 527 } else 528 host = *av; 529 if (ac > 1) { 530 optind = optreset = 1; 531 goto again; 532 } 533 ac--, av++; 534 } 535 536 /* Check that we got a host name. */ 537 if (!host) 538 usage(); 539 540 SSLeay_add_all_algorithms(); 541 ERR_load_crypto_strings(); 542 543 /* Initialize the command to execute on remote host. */ 544 buffer_init(&command); 545 546 /* 547 * Save the command to execute on the remote host in a buffer. There 548 * is no limit on the length of the command, except by the maximum 549 * packet size. Also sets the tty flag if there is no command. 550 */ 551 if (!ac) { 552 /* No command specified - execute shell on a tty. */ 553 tty_flag = 1; 554 if (subsystem_flag) { 555 fprintf(stderr, 556 "You must specify a subsystem to invoke.\n"); 557 usage(); 558 } 559 } else { 560 /* A command has been specified. Store it into the buffer. */ 561 for (i = 0; i < ac; i++) { 562 if (i) 563 buffer_append(&command, " ", 1); 564 buffer_append(&command, av[i], strlen(av[i])); 565 } 566 } 567 568 /* Cannot fork to background if no command. */ 569 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 570 !no_shell_flag) 571 fatal("Cannot fork into background without a command " 572 "to execute."); 573 574 /* Allocate a tty by default if no command specified. */ 575 if (buffer_len(&command) == 0) 576 tty_flag = 1; 577 578 /* Force no tty */ 579 if (no_tty_flag) 580 tty_flag = 0; 581 /* Do not allocate a tty if stdin is not a tty. */ 582 if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) { 583 if (tty_flag) 584 logit("Pseudo-terminal will not be allocated because " 585 "stdin is not a terminal."); 586 tty_flag = 0; 587 } 588 589 /* 590 * Initialize "log" output. Since we are the client all output 591 * actually goes to stderr. 592 */ 593 log_init(argv0, 594 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 595 SYSLOG_FACILITY_USER, !use_syslog); 596 597 /* 598 * Read per-user configuration file. Ignore the system wide config 599 * file if the user specifies a config file on the command line. 600 */ 601 if (config != NULL) { 602 if (!read_config_file(config, host, &options, 0)) 603 fatal("Can't open user config file %.100s: " 604 "%.100s", config, strerror(errno)); 605 } else { 606 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, 607 _PATH_SSH_USER_CONFFILE); 608 if (r > 0 && (size_t)r < sizeof(buf)) 609 (void)read_config_file(buf, host, &options, 1); 610 611 /* Read systemwide configuration file after use config. */ 612 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, 613 &options, 0); 614 } 615 616 /* Fill configuration defaults. */ 617 fill_default_options(&options); 618 619 channel_set_af(options.address_family); 620 621 /* reinit */ 622 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 623 624 if (options.user == NULL) 625 options.user = xstrdup(pw->pw_name); 626 627 /* Get default port if port has not been set. */ 628 if (options.port == 0) { 629 sp = getservbyname(SSH_SERVICE_NAME, "tcp"); 630 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; 631 } 632 633 if (options.local_command != NULL) { 634 char thishost[NI_MAXHOST]; 635 636 if (gethostname(thishost, sizeof(thishost)) == -1) 637 fatal("gethostname: %s", strerror(errno)); 638 snprintf(buf, sizeof(buf), "%d", options.port); 639 debug3("expanding LocalCommand: %s", options.local_command); 640 cp = options.local_command; 641 options.local_command = percent_expand(cp, "d", pw->pw_dir, 642 "h", options.hostname? options.hostname : host, 643 "l", thishost, "n", host, "r", options.user, "p", buf, 644 "u", pw->pw_name, (char *)NULL); 645 debug3("expanded LocalCommand: %s", options.local_command); 646 xfree(cp); 647 } 648 649 if (options.hostname != NULL) 650 host = options.hostname; 651 652 /* force lowercase for hostkey matching */ 653 if (options.host_key_alias != NULL) { 654 for (p = options.host_key_alias; *p; p++) 655 if (isupper(*p)) 656 *p = (char)tolower(*p); 657 } 658 659 if (options.proxy_command != NULL && 660 strcmp(options.proxy_command, "none") == 0) { 661 xfree(options.proxy_command); 662 options.proxy_command = NULL; 663 } 664 if (options.control_path != NULL && 665 strcmp(options.control_path, "none") == 0) { 666 xfree(options.control_path); 667 options.control_path = NULL; 668 } 669 670 if (options.control_path != NULL) { 671 char thishost[NI_MAXHOST]; 672 673 if (gethostname(thishost, sizeof(thishost)) == -1) 674 fatal("gethostname: %s", strerror(errno)); 675 snprintf(buf, sizeof(buf), "%d", options.port); 676 cp = tilde_expand_filename(options.control_path, 677 original_real_uid); 678 xfree(options.control_path); 679 options.control_path = percent_expand(cp, "p", buf, "h", host, 680 "r", options.user, "l", thishost, (char *)NULL); 681 xfree(cp); 682 } 683 if (muxclient_command != 0 && options.control_path == NULL) 684 fatal("No ControlPath specified for \"-O\" command"); 685 if (options.control_path != NULL) 686 muxclient(options.control_path); 687 688 timeout_ms = options.connection_timeout * 1000; 689 690 /* Open a connection to the remote host. */ 691 if (ssh_connect(host, &hostaddr, options.port, 692 options.address_family, options.connection_attempts, &timeout_ms, 693 options.tcp_keep_alive, 694 original_effective_uid == 0 && options.use_privileged_port, 695 options.proxy_command) != 0) 696 exit(255); 697 698 if (timeout_ms > 0) 699 debug3("timeout: %d ms remain after connect", timeout_ms); 700 701 /* 702 * If we successfully made the connection, load the host private key 703 * in case we will need it later for combined rsa-rhosts 704 * authentication. This must be done before releasing extra 705 * privileges, because the file is only readable by root. 706 * If we cannot access the private keys, load the public keys 707 * instead and try to execute the ssh-keysign helper instead. 708 */ 709 sensitive_data.nkeys = 0; 710 sensitive_data.keys = NULL; 711 sensitive_data.external_keysign = 0; 712 if (options.rhosts_rsa_authentication || 713 options.hostbased_authentication) { 714 sensitive_data.nkeys = 3; 715 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 716 sizeof(Key)); 717 718 PRIV_START; 719 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 720 _PATH_HOST_KEY_FILE, "", NULL, NULL); 721 sensitive_data.keys[1] = key_load_private_type(KEY_DSA, 722 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 723 sensitive_data.keys[2] = key_load_private_type(KEY_RSA, 724 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 725 PRIV_END; 726 727 if (options.hostbased_authentication == 1 && 728 sensitive_data.keys[0] == NULL && 729 sensitive_data.keys[1] == NULL && 730 sensitive_data.keys[2] == NULL) { 731 sensitive_data.keys[1] = key_load_public( 732 _PATH_HOST_DSA_KEY_FILE, NULL); 733 sensitive_data.keys[2] = key_load_public( 734 _PATH_HOST_RSA_KEY_FILE, NULL); 735 sensitive_data.external_keysign = 1; 736 } 737 } 738 /* 739 * Get rid of any extra privileges that we may have. We will no 740 * longer need them. Also, extra privileges could make it very hard 741 * to read identity files and other non-world-readable files from the 742 * user's home directory if it happens to be on a NFS volume where 743 * root is mapped to nobody. 744 */ 745 if (original_effective_uid == 0) { 746 PRIV_START; 747 permanently_set_uid(pw); 748 } 749 750 /* 751 * Now that we are back to our own permissions, create ~/.ssh 752 * directory if it doesn't already exist. 753 */ 754 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 755 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 756 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) 757 if (mkdir(buf, 0700) < 0) 758 error("Could not create directory '%.200s'.", buf); 759 760 /* load options.identity_files */ 761 load_public_identity_files(); 762 763 /* Expand ~ in known host file names. */ 764 /* XXX mem-leaks: */ 765 options.system_hostfile = 766 tilde_expand_filename(options.system_hostfile, original_real_uid); 767 options.user_hostfile = 768 tilde_expand_filename(options.user_hostfile, original_real_uid); 769 options.system_hostfile2 = 770 tilde_expand_filename(options.system_hostfile2, original_real_uid); 771 options.user_hostfile2 = 772 tilde_expand_filename(options.user_hostfile2, original_real_uid); 773 774 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 775 776 /* Log into the remote system. Never returns if the login fails. */ 777 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 778 pw, timeout_ms); 779 780 /* We no longer need the private host keys. Clear them now. */ 781 if (sensitive_data.nkeys != 0) { 782 for (i = 0; i < sensitive_data.nkeys; i++) { 783 if (sensitive_data.keys[i] != NULL) { 784 /* Destroys contents safely */ 785 debug3("clear hostkey %d", i); 786 key_free(sensitive_data.keys[i]); 787 sensitive_data.keys[i] = NULL; 788 } 789 } 790 xfree(sensitive_data.keys); 791 } 792 for (i = 0; i < options.num_identity_files; i++) { 793 if (options.identity_files[i]) { 794 xfree(options.identity_files[i]); 795 options.identity_files[i] = NULL; 796 } 797 if (options.identity_keys[i]) { 798 key_free(options.identity_keys[i]); 799 options.identity_keys[i] = NULL; 800 } 801 } 802 803 exit_status = compat20 ? ssh_session2() : ssh_session(); 804 packet_close(); 805 806 if (options.control_path != NULL && muxserver_sock != -1) 807 unlink(options.control_path); 808 809 /* 810 * Send SIGHUP to proxy command if used. We don't wait() in 811 * case it hangs and instead rely on init to reap the child 812 */ 813 if (proxy_command_pid > 1) 814 kill(proxy_command_pid, SIGHUP); 815 816 return exit_status; 817 } 818 819 /* Callback for remote forward global requests */ 820 static void 821 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 822 { 823 Forward *rfwd = (Forward *)ctxt; 824 825 /* XXX verbose() on failure? */ 826 debug("remote forward %s for: listen %d, connect %s:%d", 827 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 828 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 829 if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) { 830 logit("Allocated port %u for remote forward to %s:%d", 831 packet_get_int(), 832 rfwd->connect_host, rfwd->connect_port); 833 } 834 835 if (type == SSH2_MSG_REQUEST_FAILURE) { 836 if (options.exit_on_forward_failure) 837 fatal("Error: remote port forwarding failed for " 838 "listen port %d", rfwd->listen_port); 839 else 840 logit("Warning: remote port forwarding failed for " 841 "listen port %d", rfwd->listen_port); 842 } 843 if (++remote_forward_confirms_received == options.num_remote_forwards) { 844 debug("All remote forwarding requests processed"); 845 if (fork_after_authentication_flag) { 846 fork_after_authentication_flag = 0; 847 if (daemon(1, 1) < 0) 848 fatal("daemon() failed: %.200s", 849 strerror(errno)); 850 } 851 } 852 } 853 854 static void 855 ssh_init_forwarding(void) 856 { 857 int success = 0; 858 int i; 859 860 /* Initiate local TCP/IP port forwardings. */ 861 for (i = 0; i < options.num_local_forwards; i++) { 862 debug("Local connections to %.200s:%d forwarded to remote " 863 "address %.200s:%d", 864 (options.local_forwards[i].listen_host == NULL) ? 865 (options.gateway_ports ? "*" : "LOCALHOST") : 866 options.local_forwards[i].listen_host, 867 options.local_forwards[i].listen_port, 868 options.local_forwards[i].connect_host, 869 options.local_forwards[i].connect_port); 870 success += channel_setup_local_fwd_listener( 871 options.local_forwards[i].listen_host, 872 options.local_forwards[i].listen_port, 873 options.local_forwards[i].connect_host, 874 options.local_forwards[i].connect_port, 875 options.gateway_ports); 876 } 877 if (i > 0 && success != i && options.exit_on_forward_failure) 878 fatal("Could not request local forwarding."); 879 if (i > 0 && success == 0) 880 error("Could not request local forwarding."); 881 882 /* Initiate remote TCP/IP port forwardings. */ 883 for (i = 0; i < options.num_remote_forwards; i++) { 884 debug("Remote connections from %.200s:%d forwarded to " 885 "local address %.200s:%d", 886 (options.remote_forwards[i].listen_host == NULL) ? 887 "LOCALHOST" : options.remote_forwards[i].listen_host, 888 options.remote_forwards[i].listen_port, 889 options.remote_forwards[i].connect_host, 890 options.remote_forwards[i].connect_port); 891 if (channel_request_remote_forwarding( 892 options.remote_forwards[i].listen_host, 893 options.remote_forwards[i].listen_port, 894 options.remote_forwards[i].connect_host, 895 options.remote_forwards[i].connect_port) < 0) { 896 if (options.exit_on_forward_failure) 897 fatal("Could not request remote forwarding."); 898 else 899 logit("Warning: Could not request remote " 900 "forwarding."); 901 } 902 client_register_global_confirm(ssh_confirm_remote_forward, 903 &options.remote_forwards[i]); 904 } 905 906 /* Initiate tunnel forwarding. */ 907 if (options.tun_open != SSH_TUNMODE_NO) { 908 if (client_request_tun_fwd(options.tun_open, 909 options.tun_local, options.tun_remote) == -1) { 910 if (options.exit_on_forward_failure) 911 fatal("Could not request tunnel forwarding."); 912 else 913 error("Could not request tunnel forwarding."); 914 } 915 } 916 } 917 918 static void 919 check_agent_present(void) 920 { 921 if (options.forward_agent) { 922 /* Clear agent forwarding if we don't have an agent. */ 923 if (!ssh_agent_present()) 924 options.forward_agent = 0; 925 } 926 } 927 928 static int 929 ssh_session(void) 930 { 931 int type; 932 int interactive = 0; 933 int have_tty = 0; 934 struct winsize ws; 935 char *cp; 936 const char *display; 937 938 /* Enable compression if requested. */ 939 if (options.compression) { 940 debug("Requesting compression at level %d.", 941 options.compression_level); 942 943 if (options.compression_level < 1 || 944 options.compression_level > 9) 945 fatal("Compression level must be from 1 (fast) to " 946 "9 (slow, best)."); 947 948 /* Send the request. */ 949 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 950 packet_put_int(options.compression_level); 951 packet_send(); 952 packet_write_wait(); 953 type = packet_read(); 954 if (type == SSH_SMSG_SUCCESS) 955 packet_start_compression(options.compression_level); 956 else if (type == SSH_SMSG_FAILURE) 957 logit("Warning: Remote host refused compression."); 958 else 959 packet_disconnect("Protocol error waiting for " 960 "compression response."); 961 } 962 /* Allocate a pseudo tty if appropriate. */ 963 if (tty_flag) { 964 debug("Requesting pty."); 965 966 /* Start the packet. */ 967 packet_start(SSH_CMSG_REQUEST_PTY); 968 969 /* Store TERM in the packet. There is no limit on the 970 length of the string. */ 971 cp = getenv("TERM"); 972 if (!cp) 973 cp = ""; 974 packet_put_cstring(cp); 975 976 /* Store window size in the packet. */ 977 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 978 memset(&ws, 0, sizeof(ws)); 979 packet_put_int((u_int)ws.ws_row); 980 packet_put_int((u_int)ws.ws_col); 981 packet_put_int((u_int)ws.ws_xpixel); 982 packet_put_int((u_int)ws.ws_ypixel); 983 984 /* Store tty modes in the packet. */ 985 tty_make_modes(fileno(stdin), NULL); 986 987 /* Send the packet, and wait for it to leave. */ 988 packet_send(); 989 packet_write_wait(); 990 991 /* Read response from the server. */ 992 type = packet_read(); 993 if (type == SSH_SMSG_SUCCESS) { 994 interactive = 1; 995 have_tty = 1; 996 } else if (type == SSH_SMSG_FAILURE) 997 logit("Warning: Remote host failed or refused to " 998 "allocate a pseudo tty."); 999 else 1000 packet_disconnect("Protocol error waiting for pty " 1001 "request response."); 1002 } 1003 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1004 display = getenv("DISPLAY"); 1005 if (options.forward_x11 && display != NULL) { 1006 char *proto, *data; 1007 /* Get reasonable local authentication information. */ 1008 client_x11_get_proto(display, options.xauth_location, 1009 options.forward_x11_trusted, &proto, &data); 1010 /* Request forwarding with authentication spoofing. */ 1011 debug("Requesting X11 forwarding with authentication " 1012 "spoofing."); 1013 x11_request_forwarding_with_spoofing(0, display, proto, data); 1014 1015 /* Read response from the server. */ 1016 type = packet_read(); 1017 if (type == SSH_SMSG_SUCCESS) { 1018 interactive = 1; 1019 } else if (type == SSH_SMSG_FAILURE) { 1020 logit("Warning: Remote host denied X11 forwarding."); 1021 } else { 1022 packet_disconnect("Protocol error waiting for X11 " 1023 "forwarding"); 1024 } 1025 } 1026 /* Tell the packet module whether this is an interactive session. */ 1027 packet_set_interactive(interactive); 1028 1029 /* Request authentication agent forwarding if appropriate. */ 1030 check_agent_present(); 1031 1032 if (options.forward_agent) { 1033 debug("Requesting authentication agent forwarding."); 1034 auth_request_forwarding(); 1035 1036 /* Read response from the server. */ 1037 type = packet_read(); 1038 packet_check_eom(); 1039 if (type != SSH_SMSG_SUCCESS) 1040 logit("Warning: Remote host denied authentication agent forwarding."); 1041 } 1042 1043 /* Initiate port forwardings. */ 1044 ssh_init_forwarding(); 1045 1046 /* Execute a local command */ 1047 if (options.local_command != NULL && 1048 options.permit_local_command) 1049 ssh_local_cmd(options.local_command); 1050 1051 /* 1052 * If requested and we are not interested in replies to remote 1053 * forwarding requests, then let ssh continue in the background. 1054 */ 1055 if (fork_after_authentication_flag && 1056 (!options.exit_on_forward_failure || 1057 options.num_remote_forwards == 0)) { 1058 fork_after_authentication_flag = 0; 1059 if (daemon(1, 1) < 0) 1060 fatal("daemon() failed: %.200s", strerror(errno)); 1061 } 1062 1063 /* 1064 * If a command was specified on the command line, execute the 1065 * command now. Otherwise request the server to start a shell. 1066 */ 1067 if (buffer_len(&command) > 0) { 1068 int len = buffer_len(&command); 1069 if (len > 900) 1070 len = 900; 1071 debug("Sending command: %.*s", len, 1072 (u_char *)buffer_ptr(&command)); 1073 packet_start(SSH_CMSG_EXEC_CMD); 1074 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1075 packet_send(); 1076 packet_write_wait(); 1077 } else { 1078 debug("Requesting shell."); 1079 packet_start(SSH_CMSG_EXEC_SHELL); 1080 packet_send(); 1081 packet_write_wait(); 1082 } 1083 1084 /* Enter the interactive session. */ 1085 return client_loop(have_tty, tty_flag ? 1086 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1087 } 1088 1089 /* request pty/x11/agent/tcpfwd/shell for channel */ 1090 static void 1091 ssh_session2_setup(int id, void *arg) 1092 { 1093 extern char **environ; 1094 const char *display; 1095 int interactive = tty_flag; 1096 1097 display = getenv("DISPLAY"); 1098 if (options.forward_x11 && display != NULL) { 1099 char *proto, *data; 1100 /* Get reasonable local authentication information. */ 1101 client_x11_get_proto(display, options.xauth_location, 1102 options.forward_x11_trusted, &proto, &data); 1103 /* Request forwarding with authentication spoofing. */ 1104 debug("Requesting X11 forwarding with authentication " 1105 "spoofing."); 1106 x11_request_forwarding_with_spoofing(id, display, proto, data); 1107 interactive = 1; 1108 /* XXX wait for reply */ 1109 } 1110 1111 check_agent_present(); 1112 if (options.forward_agent) { 1113 debug("Requesting authentication agent forwarding."); 1114 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1115 packet_send(); 1116 } 1117 1118 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1119 NULL, fileno(stdin), &command, environ); 1120 1121 packet_set_interactive(interactive); 1122 } 1123 1124 /* open new channel for a session */ 1125 static int 1126 ssh_session2_open(void) 1127 { 1128 Channel *c; 1129 int window, packetmax, in, out, err; 1130 1131 if (stdin_null_flag) { 1132 in = open(_PATH_DEVNULL, O_RDONLY); 1133 } else { 1134 in = dup(STDIN_FILENO); 1135 } 1136 out = dup(STDOUT_FILENO); 1137 err = dup(STDERR_FILENO); 1138 1139 if (in < 0 || out < 0 || err < 0) 1140 fatal("dup() in/out/err failed"); 1141 1142 /* enable nonblocking unless tty */ 1143 if (!isatty(in)) 1144 set_nonblock(in); 1145 if (!isatty(out)) 1146 set_nonblock(out); 1147 if (!isatty(err)) 1148 set_nonblock(err); 1149 1150 window = CHAN_SES_WINDOW_DEFAULT; 1151 packetmax = CHAN_SES_PACKET_DEFAULT; 1152 if (tty_flag) { 1153 window >>= 1; 1154 packetmax >>= 1; 1155 } 1156 c = channel_new( 1157 "session", SSH_CHANNEL_OPENING, in, out, err, 1158 window, packetmax, CHAN_EXTENDED_WRITE, 1159 "client-session", /*nonblock*/0); 1160 1161 debug3("ssh_session2_open: channel_new: %d", c->self); 1162 1163 channel_send_open(c->self); 1164 if (!no_shell_flag) 1165 channel_register_open_confirm(c->self, 1166 ssh_session2_setup, NULL); 1167 1168 return c->self; 1169 } 1170 1171 static int 1172 ssh_session2(void) 1173 { 1174 int id = -1; 1175 1176 /* XXX should be pre-session */ 1177 ssh_init_forwarding(); 1178 1179 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1180 id = ssh_session2_open(); 1181 1182 /* If we don't expect to open a new session, then disallow it */ 1183 if (options.control_master == SSHCTL_MASTER_NO && 1184 (datafellows & SSH_NEW_OPENSSH)) { 1185 debug("Requesting no-more-sessions@openssh.com"); 1186 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1187 packet_put_cstring("no-more-sessions@openssh.com"); 1188 packet_put_char(0); 1189 packet_send(); 1190 } 1191 1192 /* Execute a local command */ 1193 if (options.local_command != NULL && 1194 options.permit_local_command) 1195 ssh_local_cmd(options.local_command); 1196 1197 /* Start listening for multiplex clients */ 1198 muxserver_listen(); 1199 1200 /* If requested, let ssh continue in the background. */ 1201 if (fork_after_authentication_flag) { 1202 fork_after_authentication_flag = 0; 1203 if (daemon(1, 1) < 0) 1204 fatal("daemon() failed: %.200s", strerror(errno)); 1205 } 1206 1207 if (options.use_roaming) 1208 request_roaming(); 1209 1210 return client_loop(tty_flag, tty_flag ? 1211 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1212 } 1213 1214 static void 1215 load_public_identity_files(void) 1216 { 1217 char *filename, *cp, thishost[NI_MAXHOST]; 1218 char *pwdir = NULL, *pwname = NULL; 1219 int i = 0; 1220 Key *public; 1221 struct passwd *pw; 1222 #ifdef SMARTCARD 1223 Key **keys; 1224 1225 if (options.smartcard_device != NULL && 1226 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1227 (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) { 1228 int count = 0; 1229 for (i = 0; keys[i] != NULL; i++) { 1230 count++; 1231 memmove(&options.identity_files[1], 1232 &options.identity_files[0], 1233 sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1)); 1234 memmove(&options.identity_keys[1], 1235 &options.identity_keys[0], 1236 sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1)); 1237 options.num_identity_files++; 1238 options.identity_keys[0] = keys[i]; 1239 options.identity_files[0] = sc_get_key_label(keys[i]); 1240 } 1241 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES) 1242 options.num_identity_files = SSH_MAX_IDENTITY_FILES; 1243 i = count; 1244 xfree(keys); 1245 } 1246 #endif /* SMARTCARD */ 1247 if ((pw = getpwuid(original_real_uid)) == NULL) 1248 fatal("load_public_identity_files: getpwuid failed"); 1249 pwname = xstrdup(pw->pw_name); 1250 pwdir = xstrdup(pw->pw_dir); 1251 if (gethostname(thishost, sizeof(thishost)) == -1) 1252 fatal("load_public_identity_files: gethostname: %s", 1253 strerror(errno)); 1254 for (; i < options.num_identity_files; i++) { 1255 cp = tilde_expand_filename(options.identity_files[i], 1256 original_real_uid); 1257 filename = percent_expand(cp, "d", pwdir, 1258 "u", pwname, "l", thishost, "h", host, 1259 "r", options.user, (char *)NULL); 1260 xfree(cp); 1261 public = key_load_public(filename, NULL); 1262 debug("identity file %s type %d", filename, 1263 public ? public->type : -1); 1264 xfree(options.identity_files[i]); 1265 options.identity_files[i] = filename; 1266 options.identity_keys[i] = public; 1267 } 1268 bzero(pwname, strlen(pwname)); 1269 xfree(pwname); 1270 bzero(pwdir, strlen(pwdir)); 1271 xfree(pwdir); 1272 } 1273