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 __RCSID("$FreeBSD$"); 45 46 #include <sys/types.h> 47 #ifdef HAVE_SYS_STAT_H 48 # include <sys/stat.h> 49 #endif 50 #include <sys/resource.h> 51 #include <sys/ioctl.h> 52 #include <sys/param.h> 53 #include <sys/socket.h> 54 55 #include <ctype.h> 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <netdb.h> 59 #ifdef HAVE_PATHS_H 60 #include <paths.h> 61 #endif 62 #include <pwd.h> 63 #include <signal.h> 64 #include <stdarg.h> 65 #include <stddef.h> 66 #include <stdio.h> 67 #include <stdlib.h> 68 #include <string.h> 69 #include <unistd.h> 70 71 #include <netinet/in.h> 72 #include <arpa/inet.h> 73 74 #include <openssl/evp.h> 75 #include <openssl/err.h> 76 #include "openbsd-compat/openssl-compat.h" 77 #include "openbsd-compat/sys-queue.h" 78 79 #include "xmalloc.h" 80 #include "ssh.h" 81 #include "ssh1.h" 82 #include "ssh2.h" 83 #include "compat.h" 84 #include "cipher.h" 85 #include "packet.h" 86 #include "buffer.h" 87 #include "channels.h" 88 #include "key.h" 89 #include "authfd.h" 90 #include "authfile.h" 91 #include "pathnames.h" 92 #include "dispatch.h" 93 #include "clientloop.h" 94 #include "log.h" 95 #include "readconf.h" 96 #include "sshconnect.h" 97 #include "misc.h" 98 #include "kex.h" 99 #include "mac.h" 100 #include "sshpty.h" 101 #include "match.h" 102 #include "msg.h" 103 #include "uidswap.h" 104 #include "version.h" 105 106 #ifdef SMARTCARD 107 #include "scard.h" 108 #endif 109 110 extern char *__progname; 111 112 /* Flag indicating whether debug mode is on. May be set on the command line. */ 113 int debug_flag = 0; 114 115 /* Flag indicating whether a tty should be allocated */ 116 int tty_flag = 0; 117 int no_tty_flag = 0; 118 int force_tty_flag = 0; 119 120 /* don't exec a shell */ 121 int no_shell_flag = 0; 122 123 /* 124 * Flag indicating that nothing should be read from stdin. This can be set 125 * on the command line. 126 */ 127 int stdin_null_flag = 0; 128 129 /* 130 * Flag indicating that ssh should fork after authentication. This is useful 131 * so that the passphrase can be entered manually, and then ssh goes to the 132 * background. 133 */ 134 int fork_after_authentication_flag = 0; 135 136 /* 137 * General data structure for command line options and options configurable 138 * in configuration files. See readconf.h. 139 */ 140 Options options; 141 142 /* optional user configfile */ 143 char *config = NULL; 144 145 /* 146 * Name of the host we are connecting to. This is the name given on the 147 * command line, or the HostName specified for the user-supplied name in a 148 * configuration file. 149 */ 150 char *host; 151 152 /* socket address the host resolves to */ 153 struct sockaddr_storage hostaddr; 154 155 /* Private host keys. */ 156 Sensitive sensitive_data; 157 158 /* Original real UID. */ 159 uid_t original_real_uid; 160 uid_t original_effective_uid; 161 162 /* command to be executed */ 163 Buffer command; 164 165 /* Should we execute a command or invoke a subsystem? */ 166 int subsystem_flag = 0; 167 168 /* # of replies received for global requests */ 169 static int remote_forward_confirms_received = 0; 170 171 /* pid of proxycommand child process */ 172 pid_t proxy_command_pid = 0; 173 174 /* mux.c */ 175 extern int muxserver_sock; 176 extern u_int muxclient_command; 177 178 /* Prints a help message to the user. This function never returns. */ 179 180 static void 181 usage(void) 182 { 183 fprintf(stderr, 184 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" 185 " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n" 186 " [-i identity_file] [-L [bind_address:]port:host:hostport]\n" 187 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n" 188 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n" 189 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n" 190 ); 191 exit(255); 192 } 193 194 static int ssh_session(void); 195 static int ssh_session2(void); 196 static void load_public_identity_files(void); 197 198 /* from muxclient.c */ 199 void muxclient(const char *); 200 void muxserver_listen(void); 201 202 /* 203 * Main program for the ssh client. 204 */ 205 int 206 main(int ac, char **av) 207 { 208 int i, r, opt, exit_status, use_syslog; 209 char *p, *cp, *line, *argv0, buf[MAXPATHLEN]; 210 struct stat st; 211 struct passwd *pw; 212 int dummy, timeout_ms; 213 extern int optind, optreset; 214 extern char *optarg; 215 struct servent *sp; 216 Forward fwd; 217 218 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 219 sanitise_stdfd(); 220 221 __progname = ssh_get_progname(av[0]); 222 init_rng(); 223 224 /* 225 * Save the original real uid. It will be needed later (uid-swapping 226 * may clobber the real uid). 227 */ 228 original_real_uid = getuid(); 229 original_effective_uid = geteuid(); 230 231 /* 232 * Use uid-swapping to give up root privileges for the duration of 233 * option processing. We will re-instantiate the rights when we are 234 * ready to create the privileged port, and will permanently drop 235 * them when the port has been created (actually, when the connection 236 * has been made, as we may need to create the port several times). 237 */ 238 PRIV_END; 239 240 #ifdef HAVE_SETRLIMIT 241 /* If we are installed setuid root be careful to not drop core. */ 242 if (original_real_uid != original_effective_uid) { 243 struct rlimit rlim; 244 rlim.rlim_cur = rlim.rlim_max = 0; 245 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 246 fatal("setrlimit failed: %.100s", strerror(errno)); 247 } 248 #endif 249 /* Get user data. */ 250 pw = getpwuid(original_real_uid); 251 if (!pw) { 252 logit("You don't exist, go away!"); 253 exit(255); 254 } 255 /* Take a copy of the returned structure. */ 256 pw = pwcopy(pw); 257 258 /* 259 * Set our umask to something reasonable, as some files are created 260 * with the default umask. This will make them world-readable but 261 * writable only by the owner, which is ok for all files for which we 262 * don't set the modes explicitly. 263 */ 264 umask(022); 265 266 /* 267 * Initialize option structure to indicate that no values have been 268 * set. 269 */ 270 initialize_options(&options); 271 272 /* Parse command-line arguments. */ 273 host = NULL; 274 use_syslog = 0; 275 argv0 = av[0]; 276 277 again: 278 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 279 "ACD:F:I:KL:MNO:PR:S:TVw:XYy")) != -1) { 280 switch (opt) { 281 case '1': 282 options.protocol = SSH_PROTO_1; 283 break; 284 case '2': 285 options.protocol = SSH_PROTO_2; 286 break; 287 case '4': 288 options.address_family = AF_INET; 289 break; 290 case '6': 291 options.address_family = AF_INET6; 292 break; 293 case 'n': 294 stdin_null_flag = 1; 295 break; 296 case 'f': 297 fork_after_authentication_flag = 1; 298 stdin_null_flag = 1; 299 break; 300 case 'x': 301 options.forward_x11 = 0; 302 break; 303 case 'X': 304 options.forward_x11 = 1; 305 break; 306 case 'y': 307 use_syslog = 1; 308 break; 309 case 'Y': 310 options.forward_x11 = 1; 311 options.forward_x11_trusted = 1; 312 break; 313 case 'g': 314 options.gateway_ports = 1; 315 break; 316 case 'O': 317 if (strcmp(optarg, "check") == 0) 318 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; 319 else if (strcmp(optarg, "exit") == 0) 320 muxclient_command = SSHMUX_COMMAND_TERMINATE; 321 else 322 fatal("Invalid multiplex command."); 323 break; 324 case 'P': /* deprecated */ 325 options.use_privileged_port = 0; 326 break; 327 case 'a': 328 options.forward_agent = 0; 329 break; 330 case 'A': 331 options.forward_agent = 1; 332 break; 333 case 'k': 334 options.gss_deleg_creds = 0; 335 break; 336 case 'K': 337 options.gss_authentication = 1; 338 options.gss_deleg_creds = 1; 339 break; 340 case 'i': 341 if (stat(optarg, &st) < 0) { 342 fprintf(stderr, "Warning: Identity file %s " 343 "not accessible: %s.\n", optarg, 344 strerror(errno)); 345 break; 346 } 347 if (options.num_identity_files >= 348 SSH_MAX_IDENTITY_FILES) 349 fatal("Too many identity files specified " 350 "(max %d)", SSH_MAX_IDENTITY_FILES); 351 options.identity_files[options.num_identity_files++] = 352 xstrdup(optarg); 353 break; 354 case 'I': 355 #ifdef SMARTCARD 356 options.smartcard_device = xstrdup(optarg); 357 #else 358 fprintf(stderr, "no support for smartcards.\n"); 359 #endif 360 break; 361 case 't': 362 if (tty_flag) 363 force_tty_flag = 1; 364 tty_flag = 1; 365 break; 366 case 'v': 367 if (debug_flag == 0) { 368 debug_flag = 1; 369 options.log_level = SYSLOG_LEVEL_DEBUG1; 370 } else { 371 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 372 options.log_level++; 373 break; 374 } 375 /* FALLTHROUGH */ 376 case 'V': 377 fprintf(stderr, "%s, %s\n", 378 SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); 379 if (opt == 'V') 380 exit(0); 381 break; 382 case 'w': 383 if (options.tun_open == -1) 384 options.tun_open = SSH_TUNMODE_DEFAULT; 385 options.tun_local = a2tun(optarg, &options.tun_remote); 386 if (options.tun_local == SSH_TUNID_ERR) { 387 fprintf(stderr, 388 "Bad tun device '%s'\n", optarg); 389 exit(255); 390 } 391 break; 392 case 'q': 393 options.log_level = SYSLOG_LEVEL_QUIET; 394 break; 395 case 'e': 396 if (optarg[0] == '^' && optarg[2] == 0 && 397 (u_char) optarg[1] >= 64 && 398 (u_char) optarg[1] < 128) 399 options.escape_char = (u_char) optarg[1] & 31; 400 else if (strlen(optarg) == 1) 401 options.escape_char = (u_char) optarg[0]; 402 else if (strcmp(optarg, "none") == 0) 403 options.escape_char = SSH_ESCAPECHAR_NONE; 404 else { 405 fprintf(stderr, "Bad escape character '%s'.\n", 406 optarg); 407 exit(255); 408 } 409 break; 410 case 'c': 411 if (ciphers_valid(optarg)) { 412 /* SSH2 only */ 413 options.ciphers = xstrdup(optarg); 414 options.cipher = SSH_CIPHER_INVALID; 415 } else { 416 /* SSH1 only */ 417 options.cipher = cipher_number(optarg); 418 if (options.cipher == -1) { 419 fprintf(stderr, 420 "Unknown cipher type '%s'\n", 421 optarg); 422 exit(255); 423 } 424 if (options.cipher == SSH_CIPHER_3DES) 425 options.ciphers = "3des-cbc"; 426 else if (options.cipher == SSH_CIPHER_BLOWFISH) 427 options.ciphers = "blowfish-cbc"; 428 else 429 options.ciphers = (char *)-1; 430 } 431 break; 432 case 'm': 433 if (mac_valid(optarg)) 434 options.macs = xstrdup(optarg); 435 else { 436 fprintf(stderr, "Unknown mac type '%s'\n", 437 optarg); 438 exit(255); 439 } 440 break; 441 case 'M': 442 if (options.control_master == SSHCTL_MASTER_YES) 443 options.control_master = SSHCTL_MASTER_ASK; 444 else 445 options.control_master = SSHCTL_MASTER_YES; 446 break; 447 case 'p': 448 options.port = a2port(optarg); 449 if (options.port <= 0) { 450 fprintf(stderr, "Bad port '%s'\n", optarg); 451 exit(255); 452 } 453 break; 454 case 'l': 455 options.user = optarg; 456 break; 457 458 case 'L': 459 if (parse_forward(&fwd, optarg, 0, 0)) 460 add_local_forward(&options, &fwd); 461 else { 462 fprintf(stderr, 463 "Bad local forwarding specification '%s'\n", 464 optarg); 465 exit(255); 466 } 467 break; 468 469 case 'R': 470 if (parse_forward(&fwd, optarg, 0, 1)) { 471 add_remote_forward(&options, &fwd); 472 } else { 473 fprintf(stderr, 474 "Bad remote forwarding specification " 475 "'%s'\n", optarg); 476 exit(255); 477 } 478 break; 479 480 case 'D': 481 if (parse_forward(&fwd, optarg, 1, 0)) { 482 add_local_forward(&options, &fwd); 483 } else { 484 fprintf(stderr, 485 "Bad dynamic forwarding specification " 486 "'%s'\n", optarg); 487 exit(255); 488 } 489 break; 490 491 case 'C': 492 options.compression = 1; 493 break; 494 case 'N': 495 no_shell_flag = 1; 496 no_tty_flag = 1; 497 break; 498 case 'T': 499 no_tty_flag = 1; 500 break; 501 case 'o': 502 dummy = 1; 503 line = xstrdup(optarg); 504 if (process_config_line(&options, host ? host : "", 505 line, "command-line", 0, &dummy) != 0) 506 exit(255); 507 xfree(line); 508 break; 509 case 's': 510 subsystem_flag = 1; 511 break; 512 case 'S': 513 if (options.control_path != NULL) 514 free(options.control_path); 515 options.control_path = xstrdup(optarg); 516 break; 517 case 'b': 518 options.bind_address = optarg; 519 break; 520 case 'F': 521 config = optarg; 522 break; 523 default: 524 usage(); 525 } 526 } 527 528 ac -= optind; 529 av += optind; 530 531 if (ac > 0 && !host && **av != '-') { 532 if (strrchr(*av, '@')) { 533 p = xstrdup(*av); 534 cp = strrchr(p, '@'); 535 if (cp == NULL || cp == p) 536 usage(); 537 options.user = p; 538 *cp = '\0'; 539 host = ++cp; 540 } else 541 host = *av; 542 if (ac > 1) { 543 optind = optreset = 1; 544 goto again; 545 } 546 ac--, av++; 547 } 548 549 /* Check that we got a host name. */ 550 if (!host) 551 usage(); 552 553 SSLeay_add_all_algorithms(); 554 ERR_load_crypto_strings(); 555 556 /* Initialize the command to execute on remote host. */ 557 buffer_init(&command); 558 559 /* 560 * Save the command to execute on the remote host in a buffer. There 561 * is no limit on the length of the command, except by the maximum 562 * packet size. Also sets the tty flag if there is no command. 563 */ 564 if (!ac) { 565 /* No command specified - execute shell on a tty. */ 566 tty_flag = 1; 567 if (subsystem_flag) { 568 fprintf(stderr, 569 "You must specify a subsystem to invoke.\n"); 570 usage(); 571 } 572 } else { 573 /* A command has been specified. Store it into the buffer. */ 574 for (i = 0; i < ac; i++) { 575 if (i) 576 buffer_append(&command, " ", 1); 577 buffer_append(&command, av[i], strlen(av[i])); 578 } 579 } 580 581 /* Cannot fork to background if no command. */ 582 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 583 !no_shell_flag) 584 fatal("Cannot fork into background without a command " 585 "to execute."); 586 587 /* Allocate a tty by default if no command specified. */ 588 if (buffer_len(&command) == 0) 589 tty_flag = 1; 590 591 /* Force no tty */ 592 if (no_tty_flag) 593 tty_flag = 0; 594 /* Do not allocate a tty if stdin is not a tty. */ 595 if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) { 596 if (tty_flag) 597 logit("Pseudo-terminal will not be allocated because " 598 "stdin is not a terminal."); 599 tty_flag = 0; 600 } 601 602 /* 603 * Initialize "log" output. Since we are the client all output 604 * actually goes to stderr. 605 */ 606 log_init(argv0, 607 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 608 SYSLOG_FACILITY_USER, !use_syslog); 609 610 /* 611 * Read per-user configuration file. Ignore the system wide config 612 * file if the user specifies a config file on the command line. 613 */ 614 if (config != NULL) { 615 if (!read_config_file(config, host, &options, 0)) 616 fatal("Can't open user config file %.100s: " 617 "%.100s", config, strerror(errno)); 618 } else { 619 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, 620 _PATH_SSH_USER_CONFFILE); 621 if (r > 0 && (size_t)r < sizeof(buf)) 622 (void)read_config_file(buf, host, &options, 1); 623 624 /* Read systemwide configuration file after use config. */ 625 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, 626 &options, 0); 627 } 628 629 /* Fill configuration defaults. */ 630 fill_default_options(&options); 631 632 channel_set_af(options.address_family); 633 634 /* reinit */ 635 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 636 637 seed_rng(); 638 639 if (options.user == NULL) 640 options.user = xstrdup(pw->pw_name); 641 642 /* Get default port if port has not been set. */ 643 if (options.port == 0) { 644 sp = getservbyname(SSH_SERVICE_NAME, "tcp"); 645 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; 646 } 647 648 if (options.local_command != NULL) { 649 char thishost[NI_MAXHOST]; 650 651 if (gethostname(thishost, sizeof(thishost)) == -1) 652 fatal("gethostname: %s", strerror(errno)); 653 snprintf(buf, sizeof(buf), "%d", options.port); 654 debug3("expanding LocalCommand: %s", options.local_command); 655 cp = options.local_command; 656 options.local_command = percent_expand(cp, "d", pw->pw_dir, 657 "h", options.hostname? options.hostname : host, 658 "l", thishost, "n", host, "r", options.user, "p", buf, 659 "u", pw->pw_name, (char *)NULL); 660 debug3("expanded LocalCommand: %s", options.local_command); 661 xfree(cp); 662 } 663 664 if (options.hostname != NULL) 665 host = options.hostname; 666 667 /* Find canonic host name. */ 668 if (strchr(host, '.') == 0) { 669 struct addrinfo hints; 670 struct addrinfo *ai = NULL; 671 int errgai; 672 memset(&hints, 0, sizeof(hints)); 673 hints.ai_family = options.address_family; 674 hints.ai_flags = AI_CANONNAME; 675 hints.ai_socktype = SOCK_STREAM; 676 errgai = getaddrinfo(host, NULL, &hints, &ai); 677 if (errgai == 0) { 678 if (ai->ai_canonname != NULL) 679 host = xstrdup(ai->ai_canonname); 680 freeaddrinfo(ai); 681 } 682 } 683 684 /* force lowercase for hostkey matching */ 685 if (options.host_key_alias != NULL) { 686 for (p = options.host_key_alias; *p; p++) 687 if (isupper(*p)) 688 *p = (char)tolower(*p); 689 } 690 691 if (options.proxy_command != NULL && 692 strcmp(options.proxy_command, "none") == 0) { 693 xfree(options.proxy_command); 694 options.proxy_command = NULL; 695 } 696 if (options.control_path != NULL && 697 strcmp(options.control_path, "none") == 0) { 698 xfree(options.control_path); 699 options.control_path = NULL; 700 } 701 702 if (options.control_path != NULL) { 703 char thishost[NI_MAXHOST]; 704 705 if (gethostname(thishost, sizeof(thishost)) == -1) 706 fatal("gethostname: %s", strerror(errno)); 707 snprintf(buf, sizeof(buf), "%d", options.port); 708 cp = tilde_expand_filename(options.control_path, 709 original_real_uid); 710 xfree(options.control_path); 711 options.control_path = percent_expand(cp, "p", buf, "h", host, 712 "r", options.user, "l", thishost, (char *)NULL); 713 xfree(cp); 714 } 715 if (muxclient_command != 0 && options.control_path == NULL) 716 fatal("No ControlPath specified for \"-O\" command"); 717 if (options.control_path != NULL) 718 muxclient(options.control_path); 719 720 timeout_ms = options.connection_timeout * 1000; 721 722 /* Open a connection to the remote host. */ 723 if (ssh_connect(host, &hostaddr, options.port, 724 options.address_family, options.connection_attempts, &timeout_ms, 725 options.tcp_keep_alive, 726 #ifdef HAVE_CYGWIN 727 options.use_privileged_port, 728 #else 729 original_effective_uid == 0 && options.use_privileged_port, 730 #endif 731 options.proxy_command) != 0) 732 exit(255); 733 734 if (timeout_ms > 0) 735 debug3("timeout: %d ms remain after connect", timeout_ms); 736 737 /* 738 * If we successfully made the connection, load the host private key 739 * in case we will need it later for combined rsa-rhosts 740 * authentication. This must be done before releasing extra 741 * privileges, because the file is only readable by root. 742 * If we cannot access the private keys, load the public keys 743 * instead and try to execute the ssh-keysign helper instead. 744 */ 745 sensitive_data.nkeys = 0; 746 sensitive_data.keys = NULL; 747 sensitive_data.external_keysign = 0; 748 if (options.rhosts_rsa_authentication || 749 options.hostbased_authentication) { 750 sensitive_data.nkeys = 3; 751 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 752 sizeof(Key)); 753 754 PRIV_START; 755 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 756 _PATH_HOST_KEY_FILE, "", NULL, NULL); 757 sensitive_data.keys[1] = key_load_private_type(KEY_DSA, 758 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 759 sensitive_data.keys[2] = key_load_private_type(KEY_RSA, 760 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 761 PRIV_END; 762 763 if (options.hostbased_authentication == 1 && 764 sensitive_data.keys[0] == NULL && 765 sensitive_data.keys[1] == NULL && 766 sensitive_data.keys[2] == NULL) { 767 sensitive_data.keys[1] = key_load_public( 768 _PATH_HOST_DSA_KEY_FILE, NULL); 769 sensitive_data.keys[2] = key_load_public( 770 _PATH_HOST_RSA_KEY_FILE, NULL); 771 sensitive_data.external_keysign = 1; 772 } 773 } 774 /* 775 * Get rid of any extra privileges that we may have. We will no 776 * longer need them. Also, extra privileges could make it very hard 777 * to read identity files and other non-world-readable files from the 778 * user's home directory if it happens to be on a NFS volume where 779 * root is mapped to nobody. 780 */ 781 if (original_effective_uid == 0) { 782 PRIV_START; 783 permanently_set_uid(pw); 784 } 785 786 /* 787 * Now that we are back to our own permissions, create ~/.ssh 788 * directory if it doesn't already exist. 789 */ 790 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 791 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 792 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) 793 if (mkdir(buf, 0700) < 0) 794 error("Could not create directory '%.200s'.", buf); 795 796 /* load options.identity_files */ 797 load_public_identity_files(); 798 799 /* Expand ~ in known host file names. */ 800 /* XXX mem-leaks: */ 801 options.system_hostfile = 802 tilde_expand_filename(options.system_hostfile, original_real_uid); 803 options.user_hostfile = 804 tilde_expand_filename(options.user_hostfile, original_real_uid); 805 options.system_hostfile2 = 806 tilde_expand_filename(options.system_hostfile2, original_real_uid); 807 options.user_hostfile2 = 808 tilde_expand_filename(options.user_hostfile2, original_real_uid); 809 810 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 811 812 /* Log into the remote system. Never returns if the login fails. */ 813 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 814 pw, timeout_ms); 815 816 /* We no longer need the private host keys. Clear them now. */ 817 if (sensitive_data.nkeys != 0) { 818 for (i = 0; i < sensitive_data.nkeys; i++) { 819 if (sensitive_data.keys[i] != NULL) { 820 /* Destroys contents safely */ 821 debug3("clear hostkey %d", i); 822 key_free(sensitive_data.keys[i]); 823 sensitive_data.keys[i] = NULL; 824 } 825 } 826 xfree(sensitive_data.keys); 827 } 828 for (i = 0; i < options.num_identity_files; i++) { 829 if (options.identity_files[i]) { 830 xfree(options.identity_files[i]); 831 options.identity_files[i] = NULL; 832 } 833 if (options.identity_keys[i]) { 834 key_free(options.identity_keys[i]); 835 options.identity_keys[i] = NULL; 836 } 837 } 838 839 exit_status = compat20 ? ssh_session2() : ssh_session(); 840 packet_close(); 841 842 if (options.control_path != NULL && muxserver_sock != -1) 843 unlink(options.control_path); 844 845 /* 846 * Send SIGHUP to proxy command if used. We don't wait() in 847 * case it hangs and instead rely on init to reap the child 848 */ 849 if (proxy_command_pid > 1) 850 kill(proxy_command_pid, SIGHUP); 851 852 return exit_status; 853 } 854 855 /* Callback for remote forward global requests */ 856 static void 857 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 858 { 859 Forward *rfwd = (Forward *)ctxt; 860 861 /* XXX verbose() on failure? */ 862 debug("remote forward %s for: listen %d, connect %s:%d", 863 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 864 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 865 if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) { 866 logit("Allocated port %u for remote forward to %s:%d", 867 packet_get_int(), 868 rfwd->connect_host, rfwd->connect_port); 869 } 870 871 if (type == SSH2_MSG_REQUEST_FAILURE) { 872 if (options.exit_on_forward_failure) 873 fatal("Error: remote port forwarding failed for " 874 "listen port %d", rfwd->listen_port); 875 else 876 logit("Warning: remote port forwarding failed for " 877 "listen port %d", rfwd->listen_port); 878 } 879 if (++remote_forward_confirms_received == options.num_remote_forwards) { 880 debug("All remote forwarding requests processed"); 881 if (fork_after_authentication_flag) { 882 fork_after_authentication_flag = 0; 883 if (daemon(1, 1) < 0) 884 fatal("daemon() failed: %.200s", 885 strerror(errno)); 886 } 887 } 888 } 889 890 static void 891 ssh_init_forwarding(void) 892 { 893 int success = 0; 894 int i; 895 896 /* Initiate local TCP/IP port forwardings. */ 897 for (i = 0; i < options.num_local_forwards; i++) { 898 debug("Local connections to %.200s:%d forwarded to remote " 899 "address %.200s:%d", 900 (options.local_forwards[i].listen_host == NULL) ? 901 (options.gateway_ports ? "*" : "LOCALHOST") : 902 options.local_forwards[i].listen_host, 903 options.local_forwards[i].listen_port, 904 options.local_forwards[i].connect_host, 905 options.local_forwards[i].connect_port); 906 success += channel_setup_local_fwd_listener( 907 options.local_forwards[i].listen_host, 908 options.local_forwards[i].listen_port, 909 options.local_forwards[i].connect_host, 910 options.local_forwards[i].connect_port, 911 options.gateway_ports); 912 } 913 if (i > 0 && success != i && options.exit_on_forward_failure) 914 fatal("Could not request local forwarding."); 915 if (i > 0 && success == 0) 916 error("Could not request local forwarding."); 917 918 /* Initiate remote TCP/IP port forwardings. */ 919 for (i = 0; i < options.num_remote_forwards; i++) { 920 debug("Remote connections from %.200s:%d forwarded to " 921 "local address %.200s:%d", 922 (options.remote_forwards[i].listen_host == NULL) ? 923 "LOCALHOST" : options.remote_forwards[i].listen_host, 924 options.remote_forwards[i].listen_port, 925 options.remote_forwards[i].connect_host, 926 options.remote_forwards[i].connect_port); 927 if (channel_request_remote_forwarding( 928 options.remote_forwards[i].listen_host, 929 options.remote_forwards[i].listen_port, 930 options.remote_forwards[i].connect_host, 931 options.remote_forwards[i].connect_port) < 0) { 932 if (options.exit_on_forward_failure) 933 fatal("Could not request remote forwarding."); 934 else 935 logit("Warning: Could not request remote " 936 "forwarding."); 937 } 938 client_register_global_confirm(ssh_confirm_remote_forward, 939 &options.remote_forwards[i]); 940 } 941 942 /* Initiate tunnel forwarding. */ 943 if (options.tun_open != SSH_TUNMODE_NO) { 944 if (client_request_tun_fwd(options.tun_open, 945 options.tun_local, options.tun_remote) == -1) { 946 if (options.exit_on_forward_failure) 947 fatal("Could not request tunnel forwarding."); 948 else 949 error("Could not request tunnel forwarding."); 950 } 951 } 952 } 953 954 static void 955 check_agent_present(void) 956 { 957 if (options.forward_agent) { 958 /* Clear agent forwarding if we don't have an agent. */ 959 if (!ssh_agent_present()) 960 options.forward_agent = 0; 961 } 962 } 963 964 static int 965 ssh_session(void) 966 { 967 int type; 968 int interactive = 0; 969 int have_tty = 0; 970 struct winsize ws; 971 char *cp; 972 const char *display; 973 974 /* Enable compression if requested. */ 975 if (options.compression) { 976 debug("Requesting compression at level %d.", 977 options.compression_level); 978 979 if (options.compression_level < 1 || 980 options.compression_level > 9) 981 fatal("Compression level must be from 1 (fast) to " 982 "9 (slow, best)."); 983 984 /* Send the request. */ 985 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 986 packet_put_int(options.compression_level); 987 packet_send(); 988 packet_write_wait(); 989 type = packet_read(); 990 if (type == SSH_SMSG_SUCCESS) 991 packet_start_compression(options.compression_level); 992 else if (type == SSH_SMSG_FAILURE) 993 logit("Warning: Remote host refused compression."); 994 else 995 packet_disconnect("Protocol error waiting for " 996 "compression response."); 997 } 998 /* Allocate a pseudo tty if appropriate. */ 999 if (tty_flag) { 1000 debug("Requesting pty."); 1001 1002 /* Start the packet. */ 1003 packet_start(SSH_CMSG_REQUEST_PTY); 1004 1005 /* Store TERM in the packet. There is no limit on the 1006 length of the string. */ 1007 cp = getenv("TERM"); 1008 if (!cp) 1009 cp = ""; 1010 packet_put_cstring(cp); 1011 1012 /* Store window size in the packet. */ 1013 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1014 memset(&ws, 0, sizeof(ws)); 1015 packet_put_int((u_int)ws.ws_row); 1016 packet_put_int((u_int)ws.ws_col); 1017 packet_put_int((u_int)ws.ws_xpixel); 1018 packet_put_int((u_int)ws.ws_ypixel); 1019 1020 /* Store tty modes in the packet. */ 1021 tty_make_modes(fileno(stdin), NULL); 1022 1023 /* Send the packet, and wait for it to leave. */ 1024 packet_send(); 1025 packet_write_wait(); 1026 1027 /* Read response from the server. */ 1028 type = packet_read(); 1029 if (type == SSH_SMSG_SUCCESS) { 1030 interactive = 1; 1031 have_tty = 1; 1032 } else if (type == SSH_SMSG_FAILURE) 1033 logit("Warning: Remote host failed or refused to " 1034 "allocate a pseudo tty."); 1035 else 1036 packet_disconnect("Protocol error waiting for pty " 1037 "request response."); 1038 } 1039 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1040 display = getenv("DISPLAY"); 1041 if (options.forward_x11 && display != NULL) { 1042 char *proto, *data; 1043 /* Get reasonable local authentication information. */ 1044 client_x11_get_proto(display, options.xauth_location, 1045 options.forward_x11_trusted, &proto, &data); 1046 /* Request forwarding with authentication spoofing. */ 1047 debug("Requesting X11 forwarding with authentication " 1048 "spoofing."); 1049 x11_request_forwarding_with_spoofing(0, display, proto, data); 1050 1051 /* Read response from the server. */ 1052 type = packet_read(); 1053 if (type == SSH_SMSG_SUCCESS) { 1054 interactive = 1; 1055 } else if (type == SSH_SMSG_FAILURE) { 1056 logit("Warning: Remote host denied X11 forwarding."); 1057 } else { 1058 packet_disconnect("Protocol error waiting for X11 " 1059 "forwarding"); 1060 } 1061 } 1062 /* Tell the packet module whether this is an interactive session. */ 1063 packet_set_interactive(interactive); 1064 1065 /* Request authentication agent forwarding if appropriate. */ 1066 check_agent_present(); 1067 1068 if (options.forward_agent) { 1069 debug("Requesting authentication agent forwarding."); 1070 auth_request_forwarding(); 1071 1072 /* Read response from the server. */ 1073 type = packet_read(); 1074 packet_check_eom(); 1075 if (type != SSH_SMSG_SUCCESS) 1076 logit("Warning: Remote host denied authentication agent forwarding."); 1077 } 1078 1079 /* Initiate port forwardings. */ 1080 ssh_init_forwarding(); 1081 1082 /* Execute a local command */ 1083 if (options.local_command != NULL && 1084 options.permit_local_command) 1085 ssh_local_cmd(options.local_command); 1086 1087 /* 1088 * If requested and we are not interested in replies to remote 1089 * forwarding requests, then let ssh continue in the background. 1090 */ 1091 if (fork_after_authentication_flag && 1092 (!options.exit_on_forward_failure || 1093 options.num_remote_forwards == 0)) { 1094 fork_after_authentication_flag = 0; 1095 if (daemon(1, 1) < 0) 1096 fatal("daemon() failed: %.200s", strerror(errno)); 1097 } 1098 1099 /* 1100 * If a command was specified on the command line, execute the 1101 * command now. Otherwise request the server to start a shell. 1102 */ 1103 if (buffer_len(&command) > 0) { 1104 int len = buffer_len(&command); 1105 if (len > 900) 1106 len = 900; 1107 debug("Sending command: %.*s", len, 1108 (u_char *)buffer_ptr(&command)); 1109 packet_start(SSH_CMSG_EXEC_CMD); 1110 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1111 packet_send(); 1112 packet_write_wait(); 1113 } else { 1114 debug("Requesting shell."); 1115 packet_start(SSH_CMSG_EXEC_SHELL); 1116 packet_send(); 1117 packet_write_wait(); 1118 } 1119 1120 /* Enter the interactive session. */ 1121 return client_loop(have_tty, tty_flag ? 1122 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1123 } 1124 1125 /* request pty/x11/agent/tcpfwd/shell for channel */ 1126 static void 1127 ssh_session2_setup(int id, void *arg) 1128 { 1129 extern char **environ; 1130 const char *display; 1131 int interactive = tty_flag; 1132 1133 display = getenv("DISPLAY"); 1134 if (options.forward_x11 && display != NULL) { 1135 char *proto, *data; 1136 /* Get reasonable local authentication information. */ 1137 client_x11_get_proto(display, options.xauth_location, 1138 options.forward_x11_trusted, &proto, &data); 1139 /* Request forwarding with authentication spoofing. */ 1140 debug("Requesting X11 forwarding with authentication " 1141 "spoofing."); 1142 x11_request_forwarding_with_spoofing(id, display, proto, data); 1143 interactive = 1; 1144 /* XXX wait for reply */ 1145 } 1146 1147 check_agent_present(); 1148 if (options.forward_agent) { 1149 debug("Requesting authentication agent forwarding."); 1150 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1151 packet_send(); 1152 } 1153 1154 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1155 NULL, fileno(stdin), &command, environ); 1156 1157 packet_set_interactive(interactive); 1158 } 1159 1160 /* open new channel for a session */ 1161 static int 1162 ssh_session2_open(void) 1163 { 1164 Channel *c; 1165 int window, packetmax, in, out, err; 1166 1167 if (stdin_null_flag) { 1168 in = open(_PATH_DEVNULL, O_RDONLY); 1169 } else { 1170 in = dup(STDIN_FILENO); 1171 } 1172 out = dup(STDOUT_FILENO); 1173 err = dup(STDERR_FILENO); 1174 1175 if (in < 0 || out < 0 || err < 0) 1176 fatal("dup() in/out/err failed"); 1177 1178 /* enable nonblocking unless tty */ 1179 if (!isatty(in)) 1180 set_nonblock(in); 1181 if (!isatty(out)) 1182 set_nonblock(out); 1183 if (!isatty(err)) 1184 set_nonblock(err); 1185 1186 window = CHAN_SES_WINDOW_DEFAULT; 1187 packetmax = CHAN_SES_PACKET_DEFAULT; 1188 if (tty_flag) { 1189 window >>= 1; 1190 packetmax >>= 1; 1191 } 1192 c = channel_new( 1193 "session", SSH_CHANNEL_OPENING, in, out, err, 1194 window, packetmax, CHAN_EXTENDED_WRITE, 1195 "client-session", /*nonblock*/0); 1196 1197 debug3("ssh_session2_open: channel_new: %d", c->self); 1198 1199 channel_send_open(c->self); 1200 if (!no_shell_flag) 1201 channel_register_open_confirm(c->self, 1202 ssh_session2_setup, NULL); 1203 1204 return c->self; 1205 } 1206 1207 static int 1208 ssh_session2(void) 1209 { 1210 int id = -1; 1211 1212 /* XXX should be pre-session */ 1213 ssh_init_forwarding(); 1214 1215 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1216 id = ssh_session2_open(); 1217 1218 /* If we don't expect to open a new session, then disallow it */ 1219 if (options.control_master == SSHCTL_MASTER_NO && 1220 (datafellows & SSH_NEW_OPENSSH)) { 1221 debug("Requesting no-more-sessions@openssh.com"); 1222 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1223 packet_put_cstring("no-more-sessions@openssh.com"); 1224 packet_put_char(0); 1225 packet_send(); 1226 } 1227 1228 /* Execute a local command */ 1229 if (options.local_command != NULL && 1230 options.permit_local_command) 1231 ssh_local_cmd(options.local_command); 1232 1233 /* Start listening for multiplex clients */ 1234 muxserver_listen(); 1235 1236 /* If requested, let ssh continue in the background. */ 1237 if (fork_after_authentication_flag) { 1238 fork_after_authentication_flag = 0; 1239 if (daemon(1, 1) < 0) 1240 fatal("daemon() failed: %.200s", strerror(errno)); 1241 } 1242 1243 return client_loop(tty_flag, tty_flag ? 1244 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1245 } 1246 1247 static void 1248 load_public_identity_files(void) 1249 { 1250 char *filename, *cp, thishost[NI_MAXHOST]; 1251 char *pwdir = NULL, *pwname = NULL; 1252 int i = 0; 1253 Key *public; 1254 struct passwd *pw; 1255 #ifdef SMARTCARD 1256 Key **keys; 1257 1258 if (options.smartcard_device != NULL && 1259 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1260 (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL) { 1261 int count = 0; 1262 for (i = 0; keys[i] != NULL; i++) { 1263 count++; 1264 memmove(&options.identity_files[1], 1265 &options.identity_files[0], 1266 sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1)); 1267 memmove(&options.identity_keys[1], 1268 &options.identity_keys[0], 1269 sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1)); 1270 options.num_identity_files++; 1271 options.identity_keys[0] = keys[i]; 1272 options.identity_files[0] = sc_get_key_label(keys[i]); 1273 } 1274 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES) 1275 options.num_identity_files = SSH_MAX_IDENTITY_FILES; 1276 i = count; 1277 xfree(keys); 1278 } 1279 #endif /* SMARTCARD */ 1280 if ((pw = getpwuid(original_real_uid)) == NULL) 1281 fatal("load_public_identity_files: getpwuid failed"); 1282 pwname = xstrdup(pw->pw_name); 1283 pwdir = xstrdup(pw->pw_dir); 1284 if (gethostname(thishost, sizeof(thishost)) == -1) 1285 fatal("load_public_identity_files: gethostname: %s", 1286 strerror(errno)); 1287 for (; i < options.num_identity_files; i++) { 1288 cp = tilde_expand_filename(options.identity_files[i], 1289 original_real_uid); 1290 filename = percent_expand(cp, "d", pwdir, 1291 "u", pwname, "l", thishost, "h", host, 1292 "r", options.user, (char *)NULL); 1293 xfree(cp); 1294 public = key_load_public(filename, NULL); 1295 debug("identity file %s type %d", filename, 1296 public ? public->type : -1); 1297 xfree(options.identity_files[i]); 1298 options.identity_files[i] = filename; 1299 options.identity_keys[i] = public; 1300 } 1301 bzero(pwname, strlen(pwname)); 1302 xfree(pwname); 1303 bzero(pwdir, strlen(pwdir)); 1304 xfree(pwdir); 1305 } 1306