1 /* $OpenBSD: ssh.c,v 1.326 2009/07/02 02:11:47 dtucker 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/param.h> 52 #include <sys/socket.h> 53 54 #include <ctype.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <netdb.h> 58 #ifdef HAVE_PATHS_H 59 #include <paths.h> 60 #endif 61 #include <pwd.h> 62 #include <signal.h> 63 #include <stdarg.h> 64 #include <stddef.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <unistd.h> 69 70 #include <netinet/in.h> 71 #include <arpa/inet.h> 72 73 #include <openssl/evp.h> 74 #include <openssl/err.h> 75 #include "openbsd-compat/openssl-compat.h" 76 #include "openbsd-compat/sys-queue.h" 77 78 #include "xmalloc.h" 79 #include "ssh.h" 80 #include "ssh1.h" 81 #include "ssh2.h" 82 #include "compat.h" 83 #include "cipher.h" 84 #include "packet.h" 85 #include "buffer.h" 86 #include "channels.h" 87 #include "key.h" 88 #include "authfd.h" 89 #include "authfile.h" 90 #include "pathnames.h" 91 #include "dispatch.h" 92 #include "clientloop.h" 93 #include "log.h" 94 #include "readconf.h" 95 #include "sshconnect.h" 96 #include "misc.h" 97 #include "kex.h" 98 #include "mac.h" 99 #include "sshpty.h" 100 #include "match.h" 101 #include "msg.h" 102 #include "uidswap.h" 103 #include "version.h" 104 105 #ifdef SMARTCARD 106 #include "scard.h" 107 #endif 108 109 extern char *__progname; 110 111 /* Flag indicating whether debug mode is on. May be set on the command line. */ 112 int debug_flag = 0; 113 114 /* Flag indicating whether a tty should be allocated */ 115 int tty_flag = 0; 116 int no_tty_flag = 0; 117 int force_tty_flag = 0; 118 119 /* don't exec a shell */ 120 int no_shell_flag = 0; 121 122 /* 123 * Flag indicating that nothing should be read from stdin. This can be set 124 * on the command line. 125 */ 126 int stdin_null_flag = 0; 127 128 /* 129 * Flag indicating that ssh should fork after authentication. This is useful 130 * so that the passphrase can be entered manually, and then ssh goes to the 131 * background. 132 */ 133 int fork_after_authentication_flag = 0; 134 135 /* 136 * General data structure for command line options and options configurable 137 * in configuration files. See readconf.h. 138 */ 139 Options options; 140 141 /* optional user configfile */ 142 char *config = NULL; 143 144 /* 145 * Name of the host we are connecting to. This is the name given on the 146 * command line, or the HostName specified for the user-supplied name in a 147 * configuration file. 148 */ 149 char *host; 150 151 /* socket address the host resolves to */ 152 struct sockaddr_storage hostaddr; 153 154 /* Private host keys. */ 155 Sensitive sensitive_data; 156 157 /* Original real UID. */ 158 uid_t original_real_uid; 159 uid_t original_effective_uid; 160 161 /* command to be executed */ 162 Buffer command; 163 164 /* Should we execute a command or invoke a subsystem? */ 165 int subsystem_flag = 0; 166 167 /* # of replies received for global requests */ 168 static int remote_forward_confirms_received = 0; 169 170 /* pid of proxycommand child process */ 171 pid_t proxy_command_pid = 0; 172 173 /* mux.c */ 174 extern int muxserver_sock; 175 extern u_int muxclient_command; 176 177 /* Prints a help message to the user. This function never returns. */ 178 179 static void 180 usage(void) 181 { 182 fprintf(stderr, 183 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" 184 " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n" 185 " [-i identity_file] [-L [bind_address:]port:host:hostport]\n" 186 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n" 187 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n" 188 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n" 189 ); 190 exit(255); 191 } 192 193 static int ssh_session(void); 194 static int ssh_session2(void); 195 static void load_public_identity_files(void); 196 197 /* from muxclient.c */ 198 void muxclient(const char *); 199 void muxserver_listen(void); 200 201 /* 202 * Main program for the ssh client. 203 */ 204 int 205 main(int ac, char **av) 206 { 207 int i, r, opt, exit_status, use_syslog; 208 char *p, *cp, *line, *argv0, buf[MAXPATHLEN]; 209 struct stat st; 210 struct passwd *pw; 211 int dummy, timeout_ms; 212 extern int optind, optreset; 213 extern char *optarg; 214 struct servent *sp; 215 Forward fwd; 216 217 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 218 sanitise_stdfd(); 219 220 __progname = ssh_get_progname(av[0]); 221 init_rng(); 222 223 /* 224 * Save the original real uid. It will be needed later (uid-swapping 225 * may clobber the real uid). 226 */ 227 original_real_uid = getuid(); 228 original_effective_uid = geteuid(); 229 230 /* 231 * Use uid-swapping to give up root privileges for the duration of 232 * option processing. We will re-instantiate the rights when we are 233 * ready to create the privileged port, and will permanently drop 234 * them when the port has been created (actually, when the connection 235 * has been made, as we may need to create the port several times). 236 */ 237 PRIV_END; 238 239 #ifdef HAVE_SETRLIMIT 240 /* If we are installed setuid root be careful to not drop core. */ 241 if (original_real_uid != original_effective_uid) { 242 struct rlimit rlim; 243 rlim.rlim_cur = rlim.rlim_max = 0; 244 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 245 fatal("setrlimit failed: %.100s", strerror(errno)); 246 } 247 #endif 248 /* Get user data. */ 249 pw = getpwuid(original_real_uid); 250 if (!pw) { 251 logit("You don't exist, go away!"); 252 exit(255); 253 } 254 /* Take a copy of the returned structure. */ 255 pw = pwcopy(pw); 256 257 /* 258 * Set our umask to something reasonable, as some files are created 259 * with the default umask. This will make them world-readable but 260 * writable only by the owner, which is ok for all files for which we 261 * don't set the modes explicitly. 262 */ 263 umask(022); 264 265 /* 266 * Initialize option structure to indicate that no values have been 267 * set. 268 */ 269 initialize_options(&options); 270 271 /* Parse command-line arguments. */ 272 host = NULL; 273 use_syslog = 0; 274 argv0 = av[0]; 275 276 again: 277 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 278 "ACD:F:I:KL:MNO:PR:S:TVw:XYy")) != -1) { 279 switch (opt) { 280 case '1': 281 options.protocol = SSH_PROTO_1; 282 break; 283 case '2': 284 options.protocol = SSH_PROTO_2; 285 break; 286 case '4': 287 options.address_family = AF_INET; 288 break; 289 case '6': 290 options.address_family = AF_INET6; 291 break; 292 case 'n': 293 stdin_null_flag = 1; 294 break; 295 case 'f': 296 fork_after_authentication_flag = 1; 297 stdin_null_flag = 1; 298 break; 299 case 'x': 300 options.forward_x11 = 0; 301 break; 302 case 'X': 303 options.forward_x11 = 1; 304 break; 305 case 'y': 306 use_syslog = 1; 307 break; 308 case 'Y': 309 options.forward_x11 = 1; 310 options.forward_x11_trusted = 1; 311 break; 312 case 'g': 313 options.gateway_ports = 1; 314 break; 315 case 'O': 316 if (strcmp(optarg, "check") == 0) 317 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; 318 else if (strcmp(optarg, "exit") == 0) 319 muxclient_command = SSHMUX_COMMAND_TERMINATE; 320 else 321 fatal("Invalid multiplex command."); 322 break; 323 case 'P': /* deprecated */ 324 options.use_privileged_port = 0; 325 break; 326 case 'a': 327 options.forward_agent = 0; 328 break; 329 case 'A': 330 options.forward_agent = 1; 331 break; 332 case 'k': 333 options.gss_deleg_creds = 0; 334 break; 335 case 'K': 336 options.gss_authentication = 1; 337 options.gss_deleg_creds = 1; 338 break; 339 case 'i': 340 if (stat(optarg, &st) < 0) { 341 fprintf(stderr, "Warning: Identity file %s " 342 "not accessible: %s.\n", optarg, 343 strerror(errno)); 344 break; 345 } 346 if (options.num_identity_files >= 347 SSH_MAX_IDENTITY_FILES) 348 fatal("Too many identity files specified " 349 "(max %d)", SSH_MAX_IDENTITY_FILES); 350 options.identity_files[options.num_identity_files++] = 351 xstrdup(optarg); 352 break; 353 case 'I': 354 #ifdef SMARTCARD 355 options.smartcard_device = xstrdup(optarg); 356 #else 357 fprintf(stderr, "no support for smartcards.\n"); 358 #endif 359 break; 360 case 't': 361 if (tty_flag) 362 force_tty_flag = 1; 363 tty_flag = 1; 364 break; 365 case 'v': 366 if (debug_flag == 0) { 367 debug_flag = 1; 368 options.log_level = SYSLOG_LEVEL_DEBUG1; 369 } else { 370 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 371 options.log_level++; 372 break; 373 } 374 /* FALLTHROUGH */ 375 case 'V': 376 fprintf(stderr, "%s, %s\n", 377 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); 378 if (opt == 'V') 379 exit(0); 380 break; 381 case 'w': 382 if (options.tun_open == -1) 383 options.tun_open = SSH_TUNMODE_DEFAULT; 384 options.tun_local = a2tun(optarg, &options.tun_remote); 385 if (options.tun_local == SSH_TUNID_ERR) { 386 fprintf(stderr, 387 "Bad tun device '%s'\n", optarg); 388 exit(255); 389 } 390 break; 391 case 'q': 392 options.log_level = SYSLOG_LEVEL_QUIET; 393 break; 394 case 'e': 395 if (optarg[0] == '^' && optarg[2] == 0 && 396 (u_char) optarg[1] >= 64 && 397 (u_char) optarg[1] < 128) 398 options.escape_char = (u_char) optarg[1] & 31; 399 else if (strlen(optarg) == 1) 400 options.escape_char = (u_char) optarg[0]; 401 else if (strcmp(optarg, "none") == 0) 402 options.escape_char = SSH_ESCAPECHAR_NONE; 403 else { 404 fprintf(stderr, "Bad escape character '%s'.\n", 405 optarg); 406 exit(255); 407 } 408 break; 409 case 'c': 410 if (ciphers_valid(optarg)) { 411 /* SSH2 only */ 412 options.ciphers = xstrdup(optarg); 413 options.cipher = SSH_CIPHER_INVALID; 414 } else { 415 /* SSH1 only */ 416 options.cipher = cipher_number(optarg); 417 if (options.cipher == -1) { 418 fprintf(stderr, 419 "Unknown cipher type '%s'\n", 420 optarg); 421 exit(255); 422 } 423 if (options.cipher == SSH_CIPHER_3DES) 424 options.ciphers = "3des-cbc"; 425 else if (options.cipher == SSH_CIPHER_BLOWFISH) 426 options.ciphers = "blowfish-cbc"; 427 else 428 options.ciphers = (char *)-1; 429 } 430 break; 431 case 'm': 432 if (mac_valid(optarg)) 433 options.macs = xstrdup(optarg); 434 else { 435 fprintf(stderr, "Unknown mac type '%s'\n", 436 optarg); 437 exit(255); 438 } 439 break; 440 case 'M': 441 if (options.control_master == SSHCTL_MASTER_YES) 442 options.control_master = SSHCTL_MASTER_ASK; 443 else 444 options.control_master = SSHCTL_MASTER_YES; 445 break; 446 case 'p': 447 options.port = a2port(optarg); 448 if (options.port <= 0) { 449 fprintf(stderr, "Bad port '%s'\n", optarg); 450 exit(255); 451 } 452 break; 453 case 'l': 454 options.user = optarg; 455 break; 456 457 case 'L': 458 if (parse_forward(&fwd, optarg, 0, 0)) 459 add_local_forward(&options, &fwd); 460 else { 461 fprintf(stderr, 462 "Bad local forwarding specification '%s'\n", 463 optarg); 464 exit(255); 465 } 466 break; 467 468 case 'R': 469 if (parse_forward(&fwd, optarg, 0, 1)) { 470 add_remote_forward(&options, &fwd); 471 } else { 472 fprintf(stderr, 473 "Bad remote forwarding specification " 474 "'%s'\n", optarg); 475 exit(255); 476 } 477 break; 478 479 case 'D': 480 if (parse_forward(&fwd, optarg, 1, 0)) { 481 add_local_forward(&options, &fwd); 482 } else { 483 fprintf(stderr, 484 "Bad dynamic forwarding specification " 485 "'%s'\n", optarg); 486 exit(255); 487 } 488 break; 489 490 case 'C': 491 options.compression = 1; 492 break; 493 case 'N': 494 no_shell_flag = 1; 495 no_tty_flag = 1; 496 break; 497 case 'T': 498 no_tty_flag = 1; 499 break; 500 case 'o': 501 dummy = 1; 502 line = xstrdup(optarg); 503 if (process_config_line(&options, host ? host : "", 504 line, "command-line", 0, &dummy) != 0) 505 exit(255); 506 xfree(line); 507 break; 508 case 's': 509 subsystem_flag = 1; 510 break; 511 case 'S': 512 if (options.control_path != NULL) 513 free(options.control_path); 514 options.control_path = xstrdup(optarg); 515 break; 516 case 'b': 517 options.bind_address = optarg; 518 break; 519 case 'F': 520 config = optarg; 521 break; 522 default: 523 usage(); 524 } 525 } 526 527 ac -= optind; 528 av += optind; 529 530 if (ac > 0 && !host && **av != '-') { 531 if (strrchr(*av, '@')) { 532 p = xstrdup(*av); 533 cp = strrchr(p, '@'); 534 if (cp == NULL || cp == p) 535 usage(); 536 options.user = p; 537 *cp = '\0'; 538 host = ++cp; 539 } else 540 host = *av; 541 if (ac > 1) { 542 optind = optreset = 1; 543 goto again; 544 } 545 ac--, av++; 546 } 547 548 /* Check that we got a host name. */ 549 if (!host) 550 usage(); 551 552 SSLeay_add_all_algorithms(); 553 ERR_load_crypto_strings(); 554 555 /* Initialize the command to execute on remote host. */ 556 buffer_init(&command); 557 558 /* 559 * Save the command to execute on the remote host in a buffer. There 560 * is no limit on the length of the command, except by the maximum 561 * packet size. Also sets the tty flag if there is no command. 562 */ 563 if (!ac) { 564 /* No command specified - execute shell on a tty. */ 565 tty_flag = 1; 566 if (subsystem_flag) { 567 fprintf(stderr, 568 "You must specify a subsystem to invoke.\n"); 569 usage(); 570 } 571 } else { 572 /* A command has been specified. Store it into the buffer. */ 573 for (i = 0; i < ac; i++) { 574 if (i) 575 buffer_append(&command, " ", 1); 576 buffer_append(&command, av[i], strlen(av[i])); 577 } 578 } 579 580 /* Cannot fork to background if no command. */ 581 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 582 !no_shell_flag) 583 fatal("Cannot fork into background without a command " 584 "to execute."); 585 586 /* Allocate a tty by default if no command specified. */ 587 if (buffer_len(&command) == 0) 588 tty_flag = 1; 589 590 /* Force no tty */ 591 if (no_tty_flag) 592 tty_flag = 0; 593 /* Do not allocate a tty if stdin is not a tty. */ 594 if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) { 595 if (tty_flag) 596 logit("Pseudo-terminal will not be allocated because " 597 "stdin is not a terminal."); 598 tty_flag = 0; 599 } 600 601 /* 602 * Initialize "log" output. Since we are the client all output 603 * actually goes to stderr. 604 */ 605 log_init(argv0, 606 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 607 SYSLOG_FACILITY_USER, !use_syslog); 608 609 /* 610 * Read per-user configuration file. Ignore the system wide config 611 * file if the user specifies a config file on the command line. 612 */ 613 if (config != NULL) { 614 if (!read_config_file(config, host, &options, 0)) 615 fatal("Can't open user config file %.100s: " 616 "%.100s", config, strerror(errno)); 617 } else { 618 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, 619 _PATH_SSH_USER_CONFFILE); 620 if (r > 0 && (size_t)r < sizeof(buf)) 621 (void)read_config_file(buf, host, &options, 1); 622 623 /* Read systemwide configuration file after use config. */ 624 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, 625 &options, 0); 626 } 627 628 /* Fill configuration defaults. */ 629 fill_default_options(&options); 630 631 channel_set_af(options.address_family); 632 633 /* reinit */ 634 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 635 636 seed_rng(); 637 638 if (options.user == NULL) 639 options.user = xstrdup(pw->pw_name); 640 641 /* Get default port if port has not been set. */ 642 if (options.port == 0) { 643 sp = getservbyname(SSH_SERVICE_NAME, "tcp"); 644 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; 645 } 646 647 if (options.local_command != NULL) { 648 char thishost[NI_MAXHOST]; 649 650 if (gethostname(thishost, sizeof(thishost)) == -1) 651 fatal("gethostname: %s", strerror(errno)); 652 snprintf(buf, sizeof(buf), "%d", options.port); 653 debug3("expanding LocalCommand: %s", options.local_command); 654 cp = options.local_command; 655 options.local_command = percent_expand(cp, "d", pw->pw_dir, 656 "h", options.hostname? options.hostname : host, 657 "l", thishost, "n", host, "r", options.user, "p", buf, 658 "u", pw->pw_name, (char *)NULL); 659 debug3("expanded LocalCommand: %s", options.local_command); 660 xfree(cp); 661 } 662 663 if (options.hostname != NULL) 664 host = options.hostname; 665 666 /* Find canonic host name. */ 667 if (strchr(host, '.') == 0) { 668 struct addrinfo hints; 669 struct addrinfo *ai = NULL; 670 int errgai; 671 memset(&hints, 0, sizeof(hints)); 672 hints.ai_family = options.address_family; 673 hints.ai_flags = AI_CANONNAME; 674 hints.ai_socktype = SOCK_STREAM; 675 errgai = getaddrinfo(host, NULL, &hints, &ai); 676 if (errgai == 0) { 677 if (ai->ai_canonname != NULL) 678 host = xstrdup(ai->ai_canonname); 679 freeaddrinfo(ai); 680 } 681 } 682 683 /* force lowercase for hostkey matching */ 684 if (options.host_key_alias != NULL) { 685 for (p = options.host_key_alias; *p; p++) 686 if (isupper(*p)) 687 *p = (char)tolower(*p); 688 } 689 690 if (options.proxy_command != NULL && 691 strcmp(options.proxy_command, "none") == 0) { 692 xfree(options.proxy_command); 693 options.proxy_command = NULL; 694 } 695 if (options.control_path != NULL && 696 strcmp(options.control_path, "none") == 0) { 697 xfree(options.control_path); 698 options.control_path = NULL; 699 } 700 701 if (options.control_path != NULL) { 702 char thishost[NI_MAXHOST]; 703 704 if (gethostname(thishost, sizeof(thishost)) == -1) 705 fatal("gethostname: %s", strerror(errno)); 706 snprintf(buf, sizeof(buf), "%d", options.port); 707 cp = tilde_expand_filename(options.control_path, 708 original_real_uid); 709 xfree(options.control_path); 710 options.control_path = percent_expand(cp, "p", buf, "h", host, 711 "r", options.user, "l", thishost, (char *)NULL); 712 xfree(cp); 713 } 714 if (muxclient_command != 0 && options.control_path == NULL) 715 fatal("No ControlPath specified for \"-O\" command"); 716 if (options.control_path != NULL) 717 muxclient(options.control_path); 718 719 timeout_ms = options.connection_timeout * 1000; 720 721 /* Open a connection to the remote host. */ 722 if (ssh_connect(host, &hostaddr, options.port, 723 options.address_family, options.connection_attempts, &timeout_ms, 724 options.tcp_keep_alive, 725 #ifdef HAVE_CYGWIN 726 options.use_privileged_port, 727 #else 728 original_effective_uid == 0 && options.use_privileged_port, 729 #endif 730 options.proxy_command) != 0) 731 exit(255); 732 733 if (timeout_ms > 0) 734 debug3("timeout: %d ms remain after connect", timeout_ms); 735 736 /* 737 * If we successfully made the connection, load the host private key 738 * in case we will need it later for combined rsa-rhosts 739 * authentication. This must be done before releasing extra 740 * privileges, because the file is only readable by root. 741 * If we cannot access the private keys, load the public keys 742 * instead and try to execute the ssh-keysign helper instead. 743 */ 744 sensitive_data.nkeys = 0; 745 sensitive_data.keys = NULL; 746 sensitive_data.external_keysign = 0; 747 if (options.rhosts_rsa_authentication || 748 options.hostbased_authentication) { 749 sensitive_data.nkeys = 3; 750 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 751 sizeof(Key)); 752 753 PRIV_START; 754 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 755 _PATH_HOST_KEY_FILE, "", NULL, NULL); 756 sensitive_data.keys[1] = key_load_private_type(KEY_DSA, 757 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 758 sensitive_data.keys[2] = key_load_private_type(KEY_RSA, 759 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 760 PRIV_END; 761 762 if (options.hostbased_authentication == 1 && 763 sensitive_data.keys[0] == NULL && 764 sensitive_data.keys[1] == NULL && 765 sensitive_data.keys[2] == NULL) { 766 sensitive_data.keys[1] = key_load_public( 767 _PATH_HOST_DSA_KEY_FILE, NULL); 768 sensitive_data.keys[2] = key_load_public( 769 _PATH_HOST_RSA_KEY_FILE, NULL); 770 sensitive_data.external_keysign = 1; 771 } 772 } 773 /* 774 * Get rid of any extra privileges that we may have. We will no 775 * longer need them. Also, extra privileges could make it very hard 776 * to read identity files and other non-world-readable files from the 777 * user's home directory if it happens to be on a NFS volume where 778 * root is mapped to nobody. 779 */ 780 if (original_effective_uid == 0) { 781 PRIV_START; 782 permanently_set_uid(pw); 783 } 784 785 /* 786 * Now that we are back to our own permissions, create ~/.ssh 787 * directory if it doesn't already exist. 788 */ 789 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 790 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 791 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) 792 if (mkdir(buf, 0700) < 0) 793 error("Could not create directory '%.200s'.", buf); 794 795 /* load options.identity_files */ 796 load_public_identity_files(); 797 798 /* Expand ~ in known host file names. */ 799 /* XXX mem-leaks: */ 800 options.system_hostfile = 801 tilde_expand_filename(options.system_hostfile, original_real_uid); 802 options.user_hostfile = 803 tilde_expand_filename(options.user_hostfile, original_real_uid); 804 options.system_hostfile2 = 805 tilde_expand_filename(options.system_hostfile2, original_real_uid); 806 options.user_hostfile2 = 807 tilde_expand_filename(options.user_hostfile2, original_real_uid); 808 809 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 810 811 /* Log into the remote system. Never returns if the login fails. */ 812 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 813 pw, timeout_ms); 814 815 /* We no longer need the private host keys. Clear them now. */ 816 if (sensitive_data.nkeys != 0) { 817 for (i = 0; i < sensitive_data.nkeys; i++) { 818 if (sensitive_data.keys[i] != NULL) { 819 /* Destroys contents safely */ 820 debug3("clear hostkey %d", i); 821 key_free(sensitive_data.keys[i]); 822 sensitive_data.keys[i] = NULL; 823 } 824 } 825 xfree(sensitive_data.keys); 826 } 827 for (i = 0; i < options.num_identity_files; i++) { 828 if (options.identity_files[i]) { 829 xfree(options.identity_files[i]); 830 options.identity_files[i] = NULL; 831 } 832 if (options.identity_keys[i]) { 833 key_free(options.identity_keys[i]); 834 options.identity_keys[i] = NULL; 835 } 836 } 837 838 exit_status = compat20 ? ssh_session2() : ssh_session(); 839 packet_close(); 840 841 if (options.control_path != NULL && muxserver_sock != -1) 842 unlink(options.control_path); 843 844 /* 845 * Send SIGHUP to proxy command if used. We don't wait() in 846 * case it hangs and instead rely on init to reap the child 847 */ 848 if (proxy_command_pid > 1) 849 kill(proxy_command_pid, SIGHUP); 850 851 return exit_status; 852 } 853 854 /* Callback for remote forward global requests */ 855 static void 856 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 857 { 858 Forward *rfwd = (Forward *)ctxt; 859 860 /* XXX verbose() on failure? */ 861 debug("remote forward %s for: listen %d, connect %s:%d", 862 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 863 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 864 if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) { 865 logit("Allocated port %u for remote forward to %s:%d", 866 packet_get_int(), 867 rfwd->connect_host, rfwd->connect_port); 868 } 869 870 if (type == SSH2_MSG_REQUEST_FAILURE) { 871 if (options.exit_on_forward_failure) 872 fatal("Error: remote port forwarding failed for " 873 "listen port %d", rfwd->listen_port); 874 else 875 logit("Warning: remote port forwarding failed for " 876 "listen port %d", rfwd->listen_port); 877 } 878 if (++remote_forward_confirms_received == options.num_remote_forwards) { 879 debug("All remote forwarding requests processed"); 880 if (fork_after_authentication_flag) { 881 fork_after_authentication_flag = 0; 882 if (daemon(1, 1) < 0) 883 fatal("daemon() failed: %.200s", 884 strerror(errno)); 885 } 886 } 887 } 888 889 static void 890 ssh_init_forwarding(void) 891 { 892 int success = 0; 893 int i; 894 895 /* Initiate local TCP/IP port forwardings. */ 896 for (i = 0; i < options.num_local_forwards; i++) { 897 debug("Local connections to %.200s:%d forwarded to remote " 898 "address %.200s:%d", 899 (options.local_forwards[i].listen_host == NULL) ? 900 (options.gateway_ports ? "*" : "LOCALHOST") : 901 options.local_forwards[i].listen_host, 902 options.local_forwards[i].listen_port, 903 options.local_forwards[i].connect_host, 904 options.local_forwards[i].connect_port); 905 success += channel_setup_local_fwd_listener( 906 options.local_forwards[i].listen_host, 907 options.local_forwards[i].listen_port, 908 options.local_forwards[i].connect_host, 909 options.local_forwards[i].connect_port, 910 options.gateway_ports); 911 } 912 if (i > 0 && success != i && options.exit_on_forward_failure) 913 fatal("Could not request local forwarding."); 914 if (i > 0 && success == 0) 915 error("Could not request local forwarding."); 916 917 /* Initiate remote TCP/IP port forwardings. */ 918 for (i = 0; i < options.num_remote_forwards; i++) { 919 debug("Remote connections from %.200s:%d forwarded to " 920 "local address %.200s:%d", 921 (options.remote_forwards[i].listen_host == NULL) ? 922 "LOCALHOST" : options.remote_forwards[i].listen_host, 923 options.remote_forwards[i].listen_port, 924 options.remote_forwards[i].connect_host, 925 options.remote_forwards[i].connect_port); 926 if (channel_request_remote_forwarding( 927 options.remote_forwards[i].listen_host, 928 options.remote_forwards[i].listen_port, 929 options.remote_forwards[i].connect_host, 930 options.remote_forwards[i].connect_port) < 0) { 931 if (options.exit_on_forward_failure) 932 fatal("Could not request remote forwarding."); 933 else 934 logit("Warning: Could not request remote " 935 "forwarding."); 936 } 937 client_register_global_confirm(ssh_confirm_remote_forward, 938 &options.remote_forwards[i]); 939 } 940 941 /* Initiate tunnel forwarding. */ 942 if (options.tun_open != SSH_TUNMODE_NO) { 943 if (client_request_tun_fwd(options.tun_open, 944 options.tun_local, options.tun_remote) == -1) { 945 if (options.exit_on_forward_failure) 946 fatal("Could not request tunnel forwarding."); 947 else 948 error("Could not request tunnel forwarding."); 949 } 950 } 951 } 952 953 static void 954 check_agent_present(void) 955 { 956 if (options.forward_agent) { 957 /* Clear agent forwarding if we don't have an agent. */ 958 if (!ssh_agent_present()) 959 options.forward_agent = 0; 960 } 961 } 962 963 static int 964 ssh_session(void) 965 { 966 int type; 967 int interactive = 0; 968 int have_tty = 0; 969 struct winsize ws; 970 char *cp; 971 const char *display; 972 973 /* Enable compression if requested. */ 974 if (options.compression) { 975 debug("Requesting compression at level %d.", 976 options.compression_level); 977 978 if (options.compression_level < 1 || 979 options.compression_level > 9) 980 fatal("Compression level must be from 1 (fast) to " 981 "9 (slow, best)."); 982 983 /* Send the request. */ 984 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 985 packet_put_int(options.compression_level); 986 packet_send(); 987 packet_write_wait(); 988 type = packet_read(); 989 if (type == SSH_SMSG_SUCCESS) 990 packet_start_compression(options.compression_level); 991 else if (type == SSH_SMSG_FAILURE) 992 logit("Warning: Remote host refused compression."); 993 else 994 packet_disconnect("Protocol error waiting for " 995 "compression response."); 996 } 997 /* Allocate a pseudo tty if appropriate. */ 998 if (tty_flag) { 999 debug("Requesting pty."); 1000 1001 /* Start the packet. */ 1002 packet_start(SSH_CMSG_REQUEST_PTY); 1003 1004 /* Store TERM in the packet. There is no limit on the 1005 length of the string. */ 1006 cp = getenv("TERM"); 1007 if (!cp) 1008 cp = ""; 1009 packet_put_cstring(cp); 1010 1011 /* Store window size in the packet. */ 1012 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1013 memset(&ws, 0, sizeof(ws)); 1014 packet_put_int((u_int)ws.ws_row); 1015 packet_put_int((u_int)ws.ws_col); 1016 packet_put_int((u_int)ws.ws_xpixel); 1017 packet_put_int((u_int)ws.ws_ypixel); 1018 1019 /* Store tty modes in the packet. */ 1020 tty_make_modes(fileno(stdin), NULL); 1021 1022 /* Send the packet, and wait for it to leave. */ 1023 packet_send(); 1024 packet_write_wait(); 1025 1026 /* Read response from the server. */ 1027 type = packet_read(); 1028 if (type == SSH_SMSG_SUCCESS) { 1029 interactive = 1; 1030 have_tty = 1; 1031 } else if (type == SSH_SMSG_FAILURE) 1032 logit("Warning: Remote host failed or refused to " 1033 "allocate a pseudo tty."); 1034 else 1035 packet_disconnect("Protocol error waiting for pty " 1036 "request response."); 1037 } 1038 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1039 display = getenv("DISPLAY"); 1040 if (options.forward_x11 && display != NULL) { 1041 char *proto, *data; 1042 /* Get reasonable local authentication information. */ 1043 client_x11_get_proto(display, options.xauth_location, 1044 options.forward_x11_trusted, &proto, &data); 1045 /* Request forwarding with authentication spoofing. */ 1046 debug("Requesting X11 forwarding with authentication " 1047 "spoofing."); 1048 x11_request_forwarding_with_spoofing(0, display, proto, data); 1049 1050 /* Read response from the server. */ 1051 type = packet_read(); 1052 if (type == SSH_SMSG_SUCCESS) { 1053 interactive = 1; 1054 } else if (type == SSH_SMSG_FAILURE) { 1055 logit("Warning: Remote host denied X11 forwarding."); 1056 } else { 1057 packet_disconnect("Protocol error waiting for X11 " 1058 "forwarding"); 1059 } 1060 } 1061 /* Tell the packet module whether this is an interactive session. */ 1062 packet_set_interactive(interactive); 1063 1064 /* Request authentication agent forwarding if appropriate. */ 1065 check_agent_present(); 1066 1067 if (options.forward_agent) { 1068 debug("Requesting authentication agent forwarding."); 1069 auth_request_forwarding(); 1070 1071 /* Read response from the server. */ 1072 type = packet_read(); 1073 packet_check_eom(); 1074 if (type != SSH_SMSG_SUCCESS) 1075 logit("Warning: Remote host denied authentication agent forwarding."); 1076 } 1077 1078 /* Initiate port forwardings. */ 1079 ssh_init_forwarding(); 1080 1081 /* Execute a local command */ 1082 if (options.local_command != NULL && 1083 options.permit_local_command) 1084 ssh_local_cmd(options.local_command); 1085 1086 /* 1087 * If requested and we are not interested in replies to remote 1088 * forwarding requests, then let ssh continue in the background. 1089 */ 1090 if (fork_after_authentication_flag && 1091 (!options.exit_on_forward_failure || 1092 options.num_remote_forwards == 0)) { 1093 fork_after_authentication_flag = 0; 1094 if (daemon(1, 1) < 0) 1095 fatal("daemon() failed: %.200s", strerror(errno)); 1096 } 1097 1098 /* 1099 * If a command was specified on the command line, execute the 1100 * command now. Otherwise request the server to start a shell. 1101 */ 1102 if (buffer_len(&command) > 0) { 1103 int len = buffer_len(&command); 1104 if (len > 900) 1105 len = 900; 1106 debug("Sending command: %.*s", len, 1107 (u_char *)buffer_ptr(&command)); 1108 packet_start(SSH_CMSG_EXEC_CMD); 1109 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1110 packet_send(); 1111 packet_write_wait(); 1112 } else { 1113 debug("Requesting shell."); 1114 packet_start(SSH_CMSG_EXEC_SHELL); 1115 packet_send(); 1116 packet_write_wait(); 1117 } 1118 1119 /* Enter the interactive session. */ 1120 return client_loop(have_tty, tty_flag ? 1121 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1122 } 1123 1124 /* request pty/x11/agent/tcpfwd/shell for channel */ 1125 static void 1126 ssh_session2_setup(int id, void *arg) 1127 { 1128 extern char **environ; 1129 const char *display; 1130 int interactive = tty_flag; 1131 1132 display = getenv("DISPLAY"); 1133 if (options.forward_x11 && display != NULL) { 1134 char *proto, *data; 1135 /* Get reasonable local authentication information. */ 1136 client_x11_get_proto(display, options.xauth_location, 1137 options.forward_x11_trusted, &proto, &data); 1138 /* Request forwarding with authentication spoofing. */ 1139 debug("Requesting X11 forwarding with authentication " 1140 "spoofing."); 1141 x11_request_forwarding_with_spoofing(id, display, proto, data); 1142 interactive = 1; 1143 /* XXX wait for reply */ 1144 } 1145 1146 check_agent_present(); 1147 if (options.forward_agent) { 1148 debug("Requesting authentication agent forwarding."); 1149 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1150 packet_send(); 1151 } 1152 1153 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1154 NULL, fileno(stdin), &command, environ); 1155 1156 packet_set_interactive(interactive); 1157 } 1158 1159 /* open new channel for a session */ 1160 static int 1161 ssh_session2_open(void) 1162 { 1163 Channel *c; 1164 int window, packetmax, in, out, err; 1165 1166 if (stdin_null_flag) { 1167 in = open(_PATH_DEVNULL, O_RDONLY); 1168 } else { 1169 in = dup(STDIN_FILENO); 1170 } 1171 out = dup(STDOUT_FILENO); 1172 err = dup(STDERR_FILENO); 1173 1174 if (in < 0 || out < 0 || err < 0) 1175 fatal("dup() in/out/err failed"); 1176 1177 /* enable nonblocking unless tty */ 1178 if (!isatty(in)) 1179 set_nonblock(in); 1180 if (!isatty(out)) 1181 set_nonblock(out); 1182 if (!isatty(err)) 1183 set_nonblock(err); 1184 1185 window = CHAN_SES_WINDOW_DEFAULT; 1186 packetmax = CHAN_SES_PACKET_DEFAULT; 1187 if (tty_flag) { 1188 window >>= 1; 1189 packetmax >>= 1; 1190 } 1191 c = channel_new( 1192 "session", SSH_CHANNEL_OPENING, in, out, err, 1193 window, packetmax, CHAN_EXTENDED_WRITE, 1194 "client-session", /*nonblock*/0); 1195 1196 debug3("ssh_session2_open: channel_new: %d", c->self); 1197 1198 channel_send_open(c->self); 1199 if (!no_shell_flag) 1200 channel_register_open_confirm(c->self, 1201 ssh_session2_setup, NULL); 1202 1203 return c->self; 1204 } 1205 1206 static int 1207 ssh_session2(void) 1208 { 1209 int id = -1; 1210 1211 /* XXX should be pre-session */ 1212 ssh_init_forwarding(); 1213 1214 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1215 id = ssh_session2_open(); 1216 1217 /* If we don't expect to open a new session, then disallow it */ 1218 if (options.control_master == SSHCTL_MASTER_NO && 1219 (datafellows & SSH_NEW_OPENSSH)) { 1220 debug("Requesting no-more-sessions@openssh.com"); 1221 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1222 packet_put_cstring("no-more-sessions@openssh.com"); 1223 packet_put_char(0); 1224 packet_send(); 1225 } 1226 1227 /* Execute a local command */ 1228 if (options.local_command != NULL && 1229 options.permit_local_command) 1230 ssh_local_cmd(options.local_command); 1231 1232 /* Start listening for multiplex clients */ 1233 muxserver_listen(); 1234 1235 /* If requested, let ssh continue in the background. */ 1236 if (fork_after_authentication_flag) { 1237 fork_after_authentication_flag = 0; 1238 if (daemon(1, 1) < 0) 1239 fatal("daemon() failed: %.200s", strerror(errno)); 1240 } 1241 1242 return client_loop(tty_flag, tty_flag ? 1243 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1244 } 1245 1246 static void 1247 load_public_identity_files(void) 1248 { 1249 char *filename, *cp, thishost[NI_MAXHOST]; 1250 char *pwdir = NULL, *pwname = NULL; 1251 int i = 0; 1252 Key *public; 1253 struct passwd *pw; 1254 #ifdef SMARTCARD 1255 Key **keys; 1256 1257 if (options.smartcard_device != NULL && 1258 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1259 (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) { 1260 int count = 0; 1261 for (i = 0; keys[i] != NULL; i++) { 1262 count++; 1263 memmove(&options.identity_files[1], 1264 &options.identity_files[0], 1265 sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1)); 1266 memmove(&options.identity_keys[1], 1267 &options.identity_keys[0], 1268 sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1)); 1269 options.num_identity_files++; 1270 options.identity_keys[0] = keys[i]; 1271 options.identity_files[0] = sc_get_key_label(keys[i]); 1272 } 1273 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES) 1274 options.num_identity_files = SSH_MAX_IDENTITY_FILES; 1275 i = count; 1276 xfree(keys); 1277 } 1278 #endif /* SMARTCARD */ 1279 if ((pw = getpwuid(original_real_uid)) == NULL) 1280 fatal("load_public_identity_files: getpwuid failed"); 1281 pwname = xstrdup(pw->pw_name); 1282 pwdir = xstrdup(pw->pw_dir); 1283 if (gethostname(thishost, sizeof(thishost)) == -1) 1284 fatal("load_public_identity_files: gethostname: %s", 1285 strerror(errno)); 1286 for (; i < options.num_identity_files; i++) { 1287 cp = tilde_expand_filename(options.identity_files[i], 1288 original_real_uid); 1289 filename = percent_expand(cp, "d", pwdir, 1290 "u", pwname, "l", thishost, "h", host, 1291 "r", options.user, (char *)NULL); 1292 xfree(cp); 1293 public = key_load_public(filename, NULL); 1294 debug("identity file %s type %d", filename, 1295 public ? public->type : -1); 1296 xfree(options.identity_files[i]); 1297 options.identity_files[i] = filename; 1298 options.identity_keys[i] = public; 1299 } 1300 bzero(pwname, strlen(pwname)); 1301 xfree(pwname); 1302 bzero(pwdir, strlen(pwdir)); 1303 xfree(pwdir); 1304 } 1305