1 /* $OpenBSD: ssh.c,v 1.336 2010/04/10 00:00:16 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * Ssh client program. This program can be used to log into a remote machine. 7 * The software supports strong authentication, encryption, and forwarding 8 * of X11, TCP/IP, and authentication connections. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * Copyright (c) 1999 Niels Provos. All rights reserved. 17 * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved. 18 * 19 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu> 20 * in Canada (German citizen). 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 32 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 34 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 41 */ 42 43 #include <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 ENABLE_PKCS11 98 #include "ssh-pkcs11.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 /* forward stdio to remote host and port */ 128 char *stdio_forward_host = NULL; 129 int stdio_forward_port = 0; 130 131 /* 132 * General data structure for command line options and options configurable 133 * in configuration files. See readconf.h. 134 */ 135 Options options; 136 137 /* optional user configfile */ 138 char *config = NULL; 139 140 /* 141 * Name of the host we are connecting to. This is the name given on the 142 * command line, or the HostName specified for the user-supplied name in a 143 * configuration file. 144 */ 145 char *host; 146 147 /* socket address the host resolves to */ 148 struct sockaddr_storage hostaddr; 149 150 /* Private host keys. */ 151 Sensitive sensitive_data; 152 153 /* Original real UID. */ 154 uid_t original_real_uid; 155 uid_t original_effective_uid; 156 157 /* command to be executed */ 158 Buffer command; 159 160 /* Should we execute a command or invoke a subsystem? */ 161 int subsystem_flag = 0; 162 163 /* # of replies received for global requests */ 164 static int remote_forward_confirms_received = 0; 165 166 /* pid of proxycommand child process */ 167 pid_t proxy_command_pid = 0; 168 169 /* mux.c */ 170 extern int muxserver_sock; 171 extern u_int muxclient_command; 172 173 174 /* Prints a help message to the user. This function never returns. */ 175 176 static void 177 usage(void) 178 { 179 fprintf(stderr, 180 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" 181 " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n" 182 " [-I pkcs11] [-i identity_file]\n" 183 " [-L [bind_address:]port:host:hostport]\n" 184 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n" 185 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n" 186 " [-W host:port] [-w local_tun[:remote_tun]]\n" 187 " [user@]hostname [command]\n" 188 ); 189 exit(255); 190 } 191 192 static int ssh_session(void); 193 static int ssh_session2(void); 194 static void load_public_identity_files(void); 195 196 /* from muxclient.c */ 197 void muxclient(const char *); 198 void muxserver_listen(void); 199 200 /* 201 * Main program for the ssh client. 202 */ 203 int 204 main(int ac, char **av) 205 { 206 int i, r, opt, exit_status, use_syslog; 207 char *p, *cp, *line, *argv0, buf[MAXPATHLEN]; 208 struct stat st; 209 struct passwd *pw; 210 int dummy, timeout_ms; 211 extern int optind, optreset; 212 extern char *optarg; 213 struct servent *sp; 214 Forward fwd; 215 216 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 217 sanitise_stdfd(); 218 219 /* 220 * Save the original real uid. It will be needed later (uid-swapping 221 * may clobber the real uid). 222 */ 223 original_real_uid = getuid(); 224 original_effective_uid = geteuid(); 225 226 /* 227 * Use uid-swapping to give up root privileges for the duration of 228 * option processing. We will re-instantiate the rights when we are 229 * ready to create the privileged port, and will permanently drop 230 * them when the port has been created (actually, when the connection 231 * has been made, as we may need to create the port several times). 232 */ 233 PRIV_END; 234 235 /* If we are installed setuid root be careful to not drop core. */ 236 if (original_real_uid != original_effective_uid) { 237 struct rlimit rlim; 238 rlim.rlim_cur = rlim.rlim_max = 0; 239 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 240 fatal("setrlimit failed: %.100s", strerror(errno)); 241 } 242 /* Get user data. */ 243 pw = getpwuid(original_real_uid); 244 if (!pw) { 245 logit("You don't exist, go away!"); 246 exit(255); 247 } 248 /* Take a copy of the returned structure. */ 249 pw = pwcopy(pw); 250 251 /* 252 * Set our umask to something reasonable, as some files are created 253 * with the default umask. This will make them world-readable but 254 * writable only by the owner, which is ok for all files for which we 255 * don't set the modes explicitly. 256 */ 257 umask(022); 258 259 /* 260 * Initialize option structure to indicate that no values have been 261 * set. 262 */ 263 initialize_options(&options); 264 265 /* Parse command-line arguments. */ 266 host = NULL; 267 use_syslog = 0; 268 argv0 = av[0]; 269 270 again: 271 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 272 "ACD:F:I:KL:MNO:PR:S:TVw:W:XYy")) != -1) { 273 switch (opt) { 274 case '1': 275 options.protocol = SSH_PROTO_1; 276 break; 277 case '2': 278 options.protocol = SSH_PROTO_2; 279 break; 280 case '4': 281 options.address_family = AF_INET; 282 break; 283 case '6': 284 options.address_family = AF_INET6; 285 break; 286 case 'n': 287 stdin_null_flag = 1; 288 break; 289 case 'f': 290 fork_after_authentication_flag = 1; 291 stdin_null_flag = 1; 292 break; 293 case 'x': 294 options.forward_x11 = 0; 295 break; 296 case 'X': 297 options.forward_x11 = 1; 298 break; 299 case 'y': 300 use_syslog = 1; 301 break; 302 case 'Y': 303 options.forward_x11 = 1; 304 options.forward_x11_trusted = 1; 305 break; 306 case 'g': 307 options.gateway_ports = 1; 308 break; 309 case 'O': 310 if (stdio_forward_host != NULL) 311 fatal("Cannot specify multiplexing " 312 "command with -W"); 313 else if (muxclient_command != 0) 314 fatal("Multiplexing command already specified"); 315 if (strcmp(optarg, "check") == 0) 316 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; 317 else if (strcmp(optarg, "exit") == 0) 318 muxclient_command = SSHMUX_COMMAND_TERMINATE; 319 else 320 fatal("Invalid multiplex command."); 321 break; 322 case 'P': /* deprecated */ 323 options.use_privileged_port = 0; 324 break; 325 case 'a': 326 options.forward_agent = 0; 327 break; 328 case 'A': 329 options.forward_agent = 1; 330 break; 331 case 'k': 332 options.gss_deleg_creds = 0; 333 break; 334 case 'K': 335 options.gss_authentication = 1; 336 options.gss_deleg_creds = 1; 337 break; 338 case 'i': 339 if (stat(optarg, &st) < 0) { 340 fprintf(stderr, "Warning: Identity file %s " 341 "not accessible: %s.\n", optarg, 342 strerror(errno)); 343 break; 344 } 345 if (options.num_identity_files >= 346 SSH_MAX_IDENTITY_FILES) 347 fatal("Too many identity files specified " 348 "(max %d)", SSH_MAX_IDENTITY_FILES); 349 options.identity_files[options.num_identity_files++] = 350 xstrdup(optarg); 351 break; 352 case 'I': 353 #ifdef ENABLE_PKCS11 354 options.pkcs11_provider = xstrdup(optarg); 355 #else 356 fprintf(stderr, "no support for PKCS#11.\n"); 357 #endif 358 break; 359 case 't': 360 if (tty_flag) 361 force_tty_flag = 1; 362 tty_flag = 1; 363 break; 364 case 'v': 365 if (debug_flag == 0) { 366 debug_flag = 1; 367 options.log_level = SYSLOG_LEVEL_DEBUG1; 368 } else { 369 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 370 options.log_level++; 371 break; 372 } 373 /* FALLTHROUGH */ 374 case 'V': 375 fprintf(stderr, "%s, %s\n", 376 SSH_VERSION, SSLeay_version(SSLEAY_VERSION)); 377 if (opt == 'V') 378 exit(0); 379 break; 380 case 'w': 381 if (options.tun_open == -1) 382 options.tun_open = SSH_TUNMODE_DEFAULT; 383 options.tun_local = a2tun(optarg, &options.tun_remote); 384 if (options.tun_local == SSH_TUNID_ERR) { 385 fprintf(stderr, 386 "Bad tun device '%s'\n", optarg); 387 exit(255); 388 } 389 break; 390 case 'W': 391 if (stdio_forward_host != NULL) 392 fatal("stdio forward already specified"); 393 if (muxclient_command != 0) 394 fatal("Cannot specify stdio forward with -O"); 395 if (parse_forward(&fwd, optarg, 1, 0)) { 396 stdio_forward_host = fwd.listen_host; 397 stdio_forward_port = fwd.listen_port; 398 xfree(fwd.connect_host); 399 } else { 400 fprintf(stderr, 401 "Bad stdio forwarding specification '%s'\n", 402 optarg); 403 exit(255); 404 } 405 no_tty_flag = 1; 406 no_shell_flag = 1; 407 options.clear_forwardings = 1; 408 options.exit_on_forward_failure = 1; 409 break; 410 case 'q': 411 options.log_level = SYSLOG_LEVEL_QUIET; 412 break; 413 case 'e': 414 if (optarg[0] == '^' && optarg[2] == 0 && 415 (u_char) optarg[1] >= 64 && 416 (u_char) optarg[1] < 128) 417 options.escape_char = (u_char) optarg[1] & 31; 418 else if (strlen(optarg) == 1) 419 options.escape_char = (u_char) optarg[0]; 420 else if (strcmp(optarg, "none") == 0) 421 options.escape_char = SSH_ESCAPECHAR_NONE; 422 else { 423 fprintf(stderr, "Bad escape character '%s'.\n", 424 optarg); 425 exit(255); 426 } 427 break; 428 case 'c': 429 if (ciphers_valid(optarg)) { 430 /* SSH2 only */ 431 options.ciphers = xstrdup(optarg); 432 options.cipher = SSH_CIPHER_INVALID; 433 } else { 434 /* SSH1 only */ 435 options.cipher = cipher_number(optarg); 436 if (options.cipher == -1) { 437 fprintf(stderr, 438 "Unknown cipher type '%s'\n", 439 optarg); 440 exit(255); 441 } 442 if (options.cipher == SSH_CIPHER_3DES) 443 options.ciphers = "3des-cbc"; 444 else if (options.cipher == SSH_CIPHER_BLOWFISH) 445 options.ciphers = "blowfish-cbc"; 446 else 447 options.ciphers = (char *)-1; 448 } 449 break; 450 case 'm': 451 if (mac_valid(optarg)) 452 options.macs = xstrdup(optarg); 453 else { 454 fprintf(stderr, "Unknown mac type '%s'\n", 455 optarg); 456 exit(255); 457 } 458 break; 459 case 'M': 460 if (options.control_master == SSHCTL_MASTER_YES) 461 options.control_master = SSHCTL_MASTER_ASK; 462 else 463 options.control_master = SSHCTL_MASTER_YES; 464 break; 465 case 'p': 466 options.port = a2port(optarg); 467 if (options.port <= 0) { 468 fprintf(stderr, "Bad port '%s'\n", optarg); 469 exit(255); 470 } 471 break; 472 case 'l': 473 options.user = optarg; 474 break; 475 476 case 'L': 477 if (parse_forward(&fwd, optarg, 0, 0)) 478 add_local_forward(&options, &fwd); 479 else { 480 fprintf(stderr, 481 "Bad local forwarding specification '%s'\n", 482 optarg); 483 exit(255); 484 } 485 break; 486 487 case 'R': 488 if (parse_forward(&fwd, optarg, 0, 1)) { 489 add_remote_forward(&options, &fwd); 490 } else { 491 fprintf(stderr, 492 "Bad remote forwarding specification " 493 "'%s'\n", optarg); 494 exit(255); 495 } 496 break; 497 498 case 'D': 499 if (parse_forward(&fwd, optarg, 1, 0)) { 500 add_local_forward(&options, &fwd); 501 } else { 502 fprintf(stderr, 503 "Bad dynamic forwarding specification " 504 "'%s'\n", optarg); 505 exit(255); 506 } 507 break; 508 509 case 'C': 510 options.compression = 1; 511 break; 512 case 'N': 513 no_shell_flag = 1; 514 no_tty_flag = 1; 515 break; 516 case 'T': 517 no_tty_flag = 1; 518 break; 519 case 'o': 520 dummy = 1; 521 line = xstrdup(optarg); 522 if (process_config_line(&options, host ? host : "", 523 line, "command-line", 0, &dummy) != 0) 524 exit(255); 525 xfree(line); 526 break; 527 case 's': 528 subsystem_flag = 1; 529 break; 530 case 'S': 531 if (options.control_path != NULL) 532 free(options.control_path); 533 options.control_path = xstrdup(optarg); 534 break; 535 case 'b': 536 options.bind_address = optarg; 537 break; 538 case 'F': 539 config = optarg; 540 break; 541 default: 542 usage(); 543 } 544 } 545 546 ac -= optind; 547 av += optind; 548 549 if (ac > 0 && !host) { 550 if (strrchr(*av, '@')) { 551 p = xstrdup(*av); 552 cp = strrchr(p, '@'); 553 if (cp == NULL || cp == p) 554 usage(); 555 options.user = p; 556 *cp = '\0'; 557 host = ++cp; 558 } else 559 host = *av; 560 if (ac > 1) { 561 optind = optreset = 1; 562 goto again; 563 } 564 ac--, av++; 565 } 566 567 /* Check that we got a host name. */ 568 if (!host) 569 usage(); 570 571 SSLeay_add_all_algorithms(); 572 ERR_load_crypto_strings(); 573 574 /* Initialize the command to execute on remote host. */ 575 buffer_init(&command); 576 577 /* 578 * Save the command to execute on the remote host in a buffer. There 579 * is no limit on the length of the command, except by the maximum 580 * packet size. Also sets the tty flag if there is no command. 581 */ 582 if (!ac) { 583 /* No command specified - execute shell on a tty. */ 584 tty_flag = 1; 585 if (subsystem_flag) { 586 fprintf(stderr, 587 "You must specify a subsystem to invoke.\n"); 588 usage(); 589 } 590 } else { 591 /* A command has been specified. Store it into the buffer. */ 592 for (i = 0; i < ac; i++) { 593 if (i) 594 buffer_append(&command, " ", 1); 595 buffer_append(&command, av[i], strlen(av[i])); 596 } 597 } 598 599 /* Cannot fork to background if no command. */ 600 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 601 !no_shell_flag) 602 fatal("Cannot fork into background without a command " 603 "to execute."); 604 605 /* Allocate a tty by default if no command specified. */ 606 if (buffer_len(&command) == 0) 607 tty_flag = 1; 608 609 /* Force no tty */ 610 if (no_tty_flag || muxclient_command != 0) 611 tty_flag = 0; 612 /* Do not allocate a tty if stdin is not a tty. */ 613 if ((!isatty(fileno(stdin)) || stdin_null_flag) && !force_tty_flag) { 614 if (tty_flag) 615 logit("Pseudo-terminal will not be allocated because " 616 "stdin is not a terminal."); 617 tty_flag = 0; 618 } 619 620 /* 621 * Initialize "log" output. Since we are the client all output 622 * actually goes to stderr. 623 */ 624 log_init(argv0, 625 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 626 SYSLOG_FACILITY_USER, !use_syslog); 627 628 /* 629 * Read per-user configuration file. Ignore the system wide config 630 * file if the user specifies a config file on the command line. 631 */ 632 if (config != NULL) { 633 if (!read_config_file(config, host, &options, 0)) 634 fatal("Can't open user config file %.100s: " 635 "%.100s", config, strerror(errno)); 636 } else { 637 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, 638 _PATH_SSH_USER_CONFFILE); 639 if (r > 0 && (size_t)r < sizeof(buf)) 640 (void)read_config_file(buf, host, &options, 1); 641 642 /* Read systemwide configuration file after use config. */ 643 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, 644 &options, 0); 645 } 646 647 /* Fill configuration defaults. */ 648 fill_default_options(&options); 649 650 channel_set_af(options.address_family); 651 652 /* reinit */ 653 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 654 655 if (options.user == NULL) 656 options.user = xstrdup(pw->pw_name); 657 658 /* Get default port if port has not been set. */ 659 if (options.port == 0) { 660 sp = getservbyname(SSH_SERVICE_NAME, "tcp"); 661 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; 662 } 663 664 if (options.local_command != NULL) { 665 char thishost[NI_MAXHOST]; 666 667 if (gethostname(thishost, sizeof(thishost)) == -1) 668 fatal("gethostname: %s", strerror(errno)); 669 snprintf(buf, sizeof(buf), "%d", options.port); 670 debug3("expanding LocalCommand: %s", options.local_command); 671 cp = options.local_command; 672 options.local_command = percent_expand(cp, "d", pw->pw_dir, 673 "h", options.hostname? options.hostname : host, 674 "l", thishost, "n", host, "r", options.user, "p", buf, 675 "u", pw->pw_name, (char *)NULL); 676 debug3("expanded LocalCommand: %s", options.local_command); 677 xfree(cp); 678 } 679 680 if (options.hostname != NULL) 681 host = options.hostname; 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 original_effective_uid == 0 && options.use_privileged_port, 726 options.proxy_command) != 0) 727 exit(255); 728 729 if (timeout_ms > 0) 730 debug3("timeout: %d ms remain after connect", timeout_ms); 731 732 /* 733 * If we successfully made the connection, load the host private key 734 * in case we will need it later for combined rsa-rhosts 735 * authentication. This must be done before releasing extra 736 * privileges, because the file is only readable by root. 737 * If we cannot access the private keys, load the public keys 738 * instead and try to execute the ssh-keysign helper instead. 739 */ 740 sensitive_data.nkeys = 0; 741 sensitive_data.keys = NULL; 742 sensitive_data.external_keysign = 0; 743 if (options.rhosts_rsa_authentication || 744 options.hostbased_authentication) { 745 sensitive_data.nkeys = 3; 746 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 747 sizeof(Key)); 748 749 PRIV_START; 750 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 751 _PATH_HOST_KEY_FILE, "", NULL, NULL); 752 sensitive_data.keys[1] = key_load_private_type(KEY_DSA, 753 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 754 sensitive_data.keys[2] = key_load_private_type(KEY_RSA, 755 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 756 PRIV_END; 757 758 if (options.hostbased_authentication == 1 && 759 sensitive_data.keys[0] == NULL && 760 sensitive_data.keys[1] == NULL && 761 sensitive_data.keys[2] == NULL) { 762 sensitive_data.keys[1] = key_load_public( 763 _PATH_HOST_DSA_KEY_FILE, NULL); 764 sensitive_data.keys[2] = key_load_public( 765 _PATH_HOST_RSA_KEY_FILE, NULL); 766 sensitive_data.external_keysign = 1; 767 } 768 } 769 /* 770 * Get rid of any extra privileges that we may have. We will no 771 * longer need them. Also, extra privileges could make it very hard 772 * to read identity files and other non-world-readable files from the 773 * user's home directory if it happens to be on a NFS volume where 774 * root is mapped to nobody. 775 */ 776 if (original_effective_uid == 0) { 777 PRIV_START; 778 permanently_set_uid(pw); 779 } 780 781 /* 782 * Now that we are back to our own permissions, create ~/.ssh 783 * directory if it doesn't already exist. 784 */ 785 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 786 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 787 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) 788 if (mkdir(buf, 0700) < 0) 789 error("Could not create directory '%.200s'.", buf); 790 791 /* load options.identity_files */ 792 load_public_identity_files(); 793 794 /* Expand ~ in known host file names. */ 795 /* XXX mem-leaks: */ 796 options.system_hostfile = 797 tilde_expand_filename(options.system_hostfile, original_real_uid); 798 options.user_hostfile = 799 tilde_expand_filename(options.user_hostfile, original_real_uid); 800 options.system_hostfile2 = 801 tilde_expand_filename(options.system_hostfile2, original_real_uid); 802 options.user_hostfile2 = 803 tilde_expand_filename(options.user_hostfile2, original_real_uid); 804 805 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 806 807 /* Log into the remote system. Never returns if the login fails. */ 808 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 809 pw, timeout_ms); 810 811 /* We no longer need the private host keys. Clear them now. */ 812 if (sensitive_data.nkeys != 0) { 813 for (i = 0; i < sensitive_data.nkeys; i++) { 814 if (sensitive_data.keys[i] != NULL) { 815 /* Destroys contents safely */ 816 debug3("clear hostkey %d", i); 817 key_free(sensitive_data.keys[i]); 818 sensitive_data.keys[i] = NULL; 819 } 820 } 821 xfree(sensitive_data.keys); 822 } 823 for (i = 0; i < options.num_identity_files; i++) { 824 if (options.identity_files[i]) { 825 xfree(options.identity_files[i]); 826 options.identity_files[i] = NULL; 827 } 828 if (options.identity_keys[i]) { 829 key_free(options.identity_keys[i]); 830 options.identity_keys[i] = NULL; 831 } 832 } 833 834 exit_status = compat20 ? ssh_session2() : ssh_session(); 835 packet_close(); 836 837 if (options.control_path != NULL && muxserver_sock != -1) 838 unlink(options.control_path); 839 840 /* 841 * Send SIGHUP to proxy command if used. We don't wait() in 842 * case it hangs and instead rely on init to reap the child 843 */ 844 if (proxy_command_pid > 1) 845 kill(proxy_command_pid, SIGHUP); 846 847 return exit_status; 848 } 849 850 /* Callback for remote forward global requests */ 851 static void 852 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 853 { 854 Forward *rfwd = (Forward *)ctxt; 855 856 /* XXX verbose() on failure? */ 857 debug("remote forward %s for: listen %d, connect %s:%d", 858 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 859 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 860 if (type == SSH2_MSG_REQUEST_SUCCESS && rfwd->listen_port == 0) { 861 logit("Allocated port %u for remote forward to %s:%d", 862 packet_get_int(), 863 rfwd->connect_host, rfwd->connect_port); 864 } 865 866 if (type == SSH2_MSG_REQUEST_FAILURE) { 867 if (options.exit_on_forward_failure) 868 fatal("Error: remote port forwarding failed for " 869 "listen port %d", rfwd->listen_port); 870 else 871 logit("Warning: remote port forwarding failed for " 872 "listen port %d", rfwd->listen_port); 873 } 874 if (++remote_forward_confirms_received == options.num_remote_forwards) { 875 debug("All remote forwarding requests processed"); 876 if (fork_after_authentication_flag) { 877 fork_after_authentication_flag = 0; 878 if (daemon(1, 1) < 0) 879 fatal("daemon() failed: %.200s", 880 strerror(errno)); 881 } 882 } 883 } 884 885 static void 886 client_cleanup_stdio_fwd(int id, void *arg) 887 { 888 debug("stdio forwarding: done"); 889 cleanup_exit(0); 890 } 891 892 static int 893 client_setup_stdio_fwd(const char *host_to_connect, u_short port_to_connect) 894 { 895 Channel *c; 896 int in, out; 897 898 debug3("client_setup_stdio_fwd %s:%d", host_to_connect, 899 port_to_connect); 900 901 in = dup(STDIN_FILENO); 902 out = dup(STDOUT_FILENO); 903 if (in < 0 || out < 0) 904 fatal("channel_connect_stdio_fwd: dup() in/out failed"); 905 906 if ((c = channel_connect_stdio_fwd(host_to_connect, port_to_connect, 907 in, out)) == NULL) 908 return 0; 909 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0); 910 return 1; 911 } 912 913 static void 914 ssh_init_forwarding(void) 915 { 916 int success = 0; 917 int i; 918 919 if (stdio_forward_host != NULL) { 920 if (!compat20) { 921 fatal("stdio forwarding require Protocol 2"); 922 } 923 if (!client_setup_stdio_fwd(stdio_forward_host, 924 stdio_forward_port)) 925 fatal("Failed to connect in stdio forward mode."); 926 } 927 928 /* Initiate local TCP/IP port forwardings. */ 929 for (i = 0; i < options.num_local_forwards; i++) { 930 debug("Local connections to %.200s:%d forwarded to remote " 931 "address %.200s:%d", 932 (options.local_forwards[i].listen_host == NULL) ? 933 (options.gateway_ports ? "*" : "LOCALHOST") : 934 options.local_forwards[i].listen_host, 935 options.local_forwards[i].listen_port, 936 options.local_forwards[i].connect_host, 937 options.local_forwards[i].connect_port); 938 success += channel_setup_local_fwd_listener( 939 options.local_forwards[i].listen_host, 940 options.local_forwards[i].listen_port, 941 options.local_forwards[i].connect_host, 942 options.local_forwards[i].connect_port, 943 options.gateway_ports); 944 } 945 if (i > 0 && success != i && options.exit_on_forward_failure) 946 fatal("Could not request local forwarding."); 947 if (i > 0 && success == 0) 948 error("Could not request local forwarding."); 949 950 /* Initiate remote TCP/IP port forwardings. */ 951 for (i = 0; i < options.num_remote_forwards; i++) { 952 debug("Remote connections from %.200s:%d forwarded to " 953 "local address %.200s:%d", 954 (options.remote_forwards[i].listen_host == NULL) ? 955 "LOCALHOST" : options.remote_forwards[i].listen_host, 956 options.remote_forwards[i].listen_port, 957 options.remote_forwards[i].connect_host, 958 options.remote_forwards[i].connect_port); 959 if (channel_request_remote_forwarding( 960 options.remote_forwards[i].listen_host, 961 options.remote_forwards[i].listen_port, 962 options.remote_forwards[i].connect_host, 963 options.remote_forwards[i].connect_port) < 0) { 964 if (options.exit_on_forward_failure) 965 fatal("Could not request remote forwarding."); 966 else 967 logit("Warning: Could not request remote " 968 "forwarding."); 969 } 970 client_register_global_confirm(ssh_confirm_remote_forward, 971 &options.remote_forwards[i]); 972 } 973 974 /* Initiate tunnel forwarding. */ 975 if (options.tun_open != SSH_TUNMODE_NO) { 976 if (client_request_tun_fwd(options.tun_open, 977 options.tun_local, options.tun_remote) == -1) { 978 if (options.exit_on_forward_failure) 979 fatal("Could not request tunnel forwarding."); 980 else 981 error("Could not request tunnel forwarding."); 982 } 983 } 984 } 985 986 static void 987 check_agent_present(void) 988 { 989 if (options.forward_agent) { 990 /* Clear agent forwarding if we don't have an agent. */ 991 if (!ssh_agent_present()) 992 options.forward_agent = 0; 993 } 994 } 995 996 static int 997 ssh_session(void) 998 { 999 int type; 1000 int interactive = 0; 1001 int have_tty = 0; 1002 struct winsize ws; 1003 char *cp; 1004 const char *display; 1005 1006 /* Enable compression if requested. */ 1007 if (options.compression) { 1008 debug("Requesting compression at level %d.", 1009 options.compression_level); 1010 1011 if (options.compression_level < 1 || 1012 options.compression_level > 9) 1013 fatal("Compression level must be from 1 (fast) to " 1014 "9 (slow, best)."); 1015 1016 /* Send the request. */ 1017 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 1018 packet_put_int(options.compression_level); 1019 packet_send(); 1020 packet_write_wait(); 1021 type = packet_read(); 1022 if (type == SSH_SMSG_SUCCESS) 1023 packet_start_compression(options.compression_level); 1024 else if (type == SSH_SMSG_FAILURE) 1025 logit("Warning: Remote host refused compression."); 1026 else 1027 packet_disconnect("Protocol error waiting for " 1028 "compression response."); 1029 } 1030 /* Allocate a pseudo tty if appropriate. */ 1031 if (tty_flag) { 1032 debug("Requesting pty."); 1033 1034 /* Start the packet. */ 1035 packet_start(SSH_CMSG_REQUEST_PTY); 1036 1037 /* Store TERM in the packet. There is no limit on the 1038 length of the string. */ 1039 cp = getenv("TERM"); 1040 if (!cp) 1041 cp = ""; 1042 packet_put_cstring(cp); 1043 1044 /* Store window size in the packet. */ 1045 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1046 memset(&ws, 0, sizeof(ws)); 1047 packet_put_int((u_int)ws.ws_row); 1048 packet_put_int((u_int)ws.ws_col); 1049 packet_put_int((u_int)ws.ws_xpixel); 1050 packet_put_int((u_int)ws.ws_ypixel); 1051 1052 /* Store tty modes in the packet. */ 1053 tty_make_modes(fileno(stdin), NULL); 1054 1055 /* Send the packet, and wait for it to leave. */ 1056 packet_send(); 1057 packet_write_wait(); 1058 1059 /* Read response from the server. */ 1060 type = packet_read(); 1061 if (type == SSH_SMSG_SUCCESS) { 1062 interactive = 1; 1063 have_tty = 1; 1064 } else if (type == SSH_SMSG_FAILURE) 1065 logit("Warning: Remote host failed or refused to " 1066 "allocate a pseudo tty."); 1067 else 1068 packet_disconnect("Protocol error waiting for pty " 1069 "request response."); 1070 } 1071 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1072 display = getenv("DISPLAY"); 1073 if (options.forward_x11 && display != NULL) { 1074 char *proto, *data; 1075 /* Get reasonable local authentication information. */ 1076 client_x11_get_proto(display, options.xauth_location, 1077 options.forward_x11_trusted, &proto, &data); 1078 /* Request forwarding with authentication spoofing. */ 1079 debug("Requesting X11 forwarding with authentication " 1080 "spoofing."); 1081 x11_request_forwarding_with_spoofing(0, display, proto, data); 1082 1083 /* Read response from the server. */ 1084 type = packet_read(); 1085 if (type == SSH_SMSG_SUCCESS) { 1086 interactive = 1; 1087 } else if (type == SSH_SMSG_FAILURE) { 1088 logit("Warning: Remote host denied X11 forwarding."); 1089 } else { 1090 packet_disconnect("Protocol error waiting for X11 " 1091 "forwarding"); 1092 } 1093 } 1094 /* Tell the packet module whether this is an interactive session. */ 1095 packet_set_interactive(interactive); 1096 1097 /* Request authentication agent forwarding if appropriate. */ 1098 check_agent_present(); 1099 1100 if (options.forward_agent) { 1101 debug("Requesting authentication agent forwarding."); 1102 auth_request_forwarding(); 1103 1104 /* Read response from the server. */ 1105 type = packet_read(); 1106 packet_check_eom(); 1107 if (type != SSH_SMSG_SUCCESS) 1108 logit("Warning: Remote host denied authentication agent forwarding."); 1109 } 1110 1111 /* Initiate port forwardings. */ 1112 ssh_init_forwarding(); 1113 1114 /* Execute a local command */ 1115 if (options.local_command != NULL && 1116 options.permit_local_command) 1117 ssh_local_cmd(options.local_command); 1118 1119 /* 1120 * If requested and we are not interested in replies to remote 1121 * forwarding requests, then let ssh continue in the background. 1122 */ 1123 if (fork_after_authentication_flag && 1124 (!options.exit_on_forward_failure || 1125 options.num_remote_forwards == 0)) { 1126 fork_after_authentication_flag = 0; 1127 if (daemon(1, 1) < 0) 1128 fatal("daemon() failed: %.200s", strerror(errno)); 1129 } 1130 1131 /* 1132 * If a command was specified on the command line, execute the 1133 * command now. Otherwise request the server to start a shell. 1134 */ 1135 if (buffer_len(&command) > 0) { 1136 int len = buffer_len(&command); 1137 if (len > 900) 1138 len = 900; 1139 debug("Sending command: %.*s", len, 1140 (u_char *)buffer_ptr(&command)); 1141 packet_start(SSH_CMSG_EXEC_CMD); 1142 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1143 packet_send(); 1144 packet_write_wait(); 1145 } else { 1146 debug("Requesting shell."); 1147 packet_start(SSH_CMSG_EXEC_SHELL); 1148 packet_send(); 1149 packet_write_wait(); 1150 } 1151 1152 /* Enter the interactive session. */ 1153 return client_loop(have_tty, tty_flag ? 1154 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1155 } 1156 1157 /* request pty/x11/agent/tcpfwd/shell for channel */ 1158 static void 1159 ssh_session2_setup(int id, void *arg) 1160 { 1161 extern char **environ; 1162 const char *display; 1163 int interactive = tty_flag; 1164 1165 display = getenv("DISPLAY"); 1166 if (options.forward_x11 && display != NULL) { 1167 char *proto, *data; 1168 /* Get reasonable local authentication information. */ 1169 client_x11_get_proto(display, options.xauth_location, 1170 options.forward_x11_trusted, &proto, &data); 1171 /* Request forwarding with authentication spoofing. */ 1172 debug("Requesting X11 forwarding with authentication " 1173 "spoofing."); 1174 x11_request_forwarding_with_spoofing(id, display, proto, data); 1175 interactive = 1; 1176 /* XXX wait for reply */ 1177 } 1178 1179 check_agent_present(); 1180 if (options.forward_agent) { 1181 debug("Requesting authentication agent forwarding."); 1182 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1183 packet_send(); 1184 } 1185 1186 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1187 NULL, fileno(stdin), &command, environ); 1188 1189 packet_set_interactive(interactive); 1190 } 1191 1192 /* open new channel for a session */ 1193 static int 1194 ssh_session2_open(void) 1195 { 1196 Channel *c; 1197 int window, packetmax, in, out, err; 1198 1199 if (stdin_null_flag) { 1200 in = open(_PATH_DEVNULL, O_RDONLY); 1201 } else { 1202 in = dup(STDIN_FILENO); 1203 } 1204 out = dup(STDOUT_FILENO); 1205 err = dup(STDERR_FILENO); 1206 1207 if (in < 0 || out < 0 || err < 0) 1208 fatal("dup() in/out/err failed"); 1209 1210 /* enable nonblocking unless tty */ 1211 if (!isatty(in)) 1212 set_nonblock(in); 1213 if (!isatty(out)) 1214 set_nonblock(out); 1215 if (!isatty(err)) 1216 set_nonblock(err); 1217 1218 window = CHAN_SES_WINDOW_DEFAULT; 1219 packetmax = CHAN_SES_PACKET_DEFAULT; 1220 if (tty_flag) { 1221 window >>= 1; 1222 packetmax >>= 1; 1223 } 1224 c = channel_new( 1225 "session", SSH_CHANNEL_OPENING, in, out, err, 1226 window, packetmax, CHAN_EXTENDED_WRITE, 1227 "client-session", /*nonblock*/0); 1228 1229 debug3("ssh_session2_open: channel_new: %d", c->self); 1230 1231 channel_send_open(c->self); 1232 if (!no_shell_flag) 1233 channel_register_open_confirm(c->self, 1234 ssh_session2_setup, NULL); 1235 1236 return c->self; 1237 } 1238 1239 static int 1240 ssh_session2(void) 1241 { 1242 int id = -1; 1243 1244 /* XXX should be pre-session */ 1245 ssh_init_forwarding(); 1246 1247 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1248 id = ssh_session2_open(); 1249 1250 /* If we don't expect to open a new session, then disallow it */ 1251 if (options.control_master == SSHCTL_MASTER_NO && 1252 (datafellows & SSH_NEW_OPENSSH)) { 1253 debug("Requesting no-more-sessions@openssh.com"); 1254 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1255 packet_put_cstring("no-more-sessions@openssh.com"); 1256 packet_put_char(0); 1257 packet_send(); 1258 } 1259 1260 /* Execute a local command */ 1261 if (options.local_command != NULL && 1262 options.permit_local_command) 1263 ssh_local_cmd(options.local_command); 1264 1265 /* Start listening for multiplex clients */ 1266 muxserver_listen(); 1267 1268 /* If requested, let ssh continue in the background. */ 1269 if (fork_after_authentication_flag) { 1270 fork_after_authentication_flag = 0; 1271 if (daemon(1, 1) < 0) 1272 fatal("daemon() failed: %.200s", strerror(errno)); 1273 } 1274 1275 if (options.use_roaming) 1276 request_roaming(); 1277 1278 return client_loop(tty_flag, tty_flag ? 1279 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1280 } 1281 1282 static void 1283 load_public_identity_files(void) 1284 { 1285 char *filename, *cp, thishost[NI_MAXHOST]; 1286 char *pwdir = NULL, *pwname = NULL; 1287 int i = 0; 1288 Key *public; 1289 struct passwd *pw; 1290 u_int n_ids; 1291 char *identity_files[SSH_MAX_IDENTITY_FILES]; 1292 Key *identity_keys[SSH_MAX_IDENTITY_FILES]; 1293 #ifdef ENABLE_PKCS11 1294 Key **keys; 1295 int nkeys; 1296 #endif /* PKCS11 */ 1297 1298 n_ids = 0; 1299 bzero(identity_files, sizeof(identity_files)); 1300 bzero(identity_keys, sizeof(identity_keys)); 1301 1302 #ifdef ENABLE_PKCS11 1303 if (options.pkcs11_provider != NULL && 1304 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1305 (pkcs11_init(!options.batch_mode) == 0) && 1306 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL, 1307 &keys)) > 0) { 1308 for (i = 0; i < nkeys; i++) { 1309 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1310 key_free(keys[i]); 1311 continue; 1312 } 1313 identity_keys[n_ids] = keys[i]; 1314 identity_files[n_ids] = 1315 xstrdup(options.pkcs11_provider); /* XXX */ 1316 n_ids++; 1317 } 1318 xfree(keys); 1319 } 1320 #endif /* ENABLE_PKCS11 */ 1321 if ((pw = getpwuid(original_real_uid)) == NULL) 1322 fatal("load_public_identity_files: getpwuid failed"); 1323 pwname = xstrdup(pw->pw_name); 1324 pwdir = xstrdup(pw->pw_dir); 1325 if (gethostname(thishost, sizeof(thishost)) == -1) 1326 fatal("load_public_identity_files: gethostname: %s", 1327 strerror(errno)); 1328 for (i = 0; i < options.num_identity_files; i++) { 1329 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1330 xfree(options.identity_files[i]); 1331 continue; 1332 } 1333 cp = tilde_expand_filename(options.identity_files[i], 1334 original_real_uid); 1335 filename = percent_expand(cp, "d", pwdir, 1336 "u", pwname, "l", thishost, "h", host, 1337 "r", options.user, (char *)NULL); 1338 xfree(cp); 1339 public = key_load_public(filename, NULL); 1340 debug("identity file %s type %d", filename, 1341 public ? public->type : -1); 1342 xfree(options.identity_files[i]); 1343 identity_files[n_ids] = filename; 1344 identity_keys[n_ids] = public; 1345 1346 if (++n_ids >= SSH_MAX_IDENTITY_FILES) 1347 continue; 1348 1349 /* Try to add the certificate variant too */ 1350 xasprintf(&cp, "%s-cert", filename); 1351 public = key_load_public(cp, NULL); 1352 debug("identity file %s type %d", cp, 1353 public ? public->type : -1); 1354 if (public == NULL) { 1355 xfree(cp); 1356 continue; 1357 } 1358 if (!key_is_cert(public)) { 1359 debug("%s: key %s type %s is not a certificate", 1360 __func__, cp, key_type(public)); 1361 key_free(public); 1362 xfree(cp); 1363 continue; 1364 } 1365 identity_keys[n_ids] = public; 1366 /* point to the original path, most likely the private key */ 1367 identity_files[n_ids] = xstrdup(filename); 1368 n_ids++; 1369 } 1370 options.num_identity_files = n_ids; 1371 memcpy(options.identity_files, identity_files, sizeof(identity_files)); 1372 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys)); 1373 1374 bzero(pwname, strlen(pwname)); 1375 xfree(pwname); 1376 bzero(pwdir, strlen(pwdir)); 1377 xfree(pwdir); 1378 } 1379