1 /* 2 * Author: Tatu Ylonen <ylo@cs.hut.fi> 3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4 * All rights reserved 5 * Ssh client program. This program can be used to log into a remote machine. 6 * The software supports strong authentication, encryption, and forwarding 7 * of X11, TCP/IP, and authentication connections. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * Copyright (c) 1999 Niels Provos. All rights reserved. 16 * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved. 17 * 18 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu> 19 * in Canada (German citizen). 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include "includes.h" 43 RCSID("$OpenBSD: ssh.c,v 1.206 2003/12/16 15:49:51 markus Exp $"); 44 RCSID("$FreeBSD$"); 45 46 #include <openssl/evp.h> 47 #include <openssl/err.h> 48 49 #include "ssh.h" 50 #include "ssh1.h" 51 #include "ssh2.h" 52 #include "compat.h" 53 #include "cipher.h" 54 #include "xmalloc.h" 55 #include "packet.h" 56 #include "buffer.h" 57 #include "channels.h" 58 #include "key.h" 59 #include "authfd.h" 60 #include "authfile.h" 61 #include "pathnames.h" 62 #include "clientloop.h" 63 #include "log.h" 64 #include "readconf.h" 65 #include "sshconnect.h" 66 #include "tildexpand.h" 67 #include "dispatch.h" 68 #include "misc.h" 69 #include "kex.h" 70 #include "mac.h" 71 #include "sshtty.h" 72 73 #ifdef SMARTCARD 74 #include "scard.h" 75 #endif 76 77 #ifdef HAVE___PROGNAME 78 extern char *__progname; 79 #else 80 char *__progname; 81 #endif 82 83 /* Flag indicating whether debug mode is on. This can be set on the command line. */ 84 int debug_flag = 0; 85 86 /* Flag indicating whether a tty should be allocated */ 87 int tty_flag = 0; 88 int no_tty_flag = 0; 89 int force_tty_flag = 0; 90 91 /* don't exec a shell */ 92 int no_shell_flag = 0; 93 94 /* 95 * Flag indicating that nothing should be read from stdin. This can be set 96 * on the command line. 97 */ 98 int stdin_null_flag = 0; 99 100 /* 101 * Flag indicating that ssh should fork after authentication. This is useful 102 * so that the passphrase can be entered manually, and then ssh goes to the 103 * background. 104 */ 105 int fork_after_authentication_flag = 0; 106 107 /* 108 * General data structure for command line options and options configurable 109 * in configuration files. See readconf.h. 110 */ 111 Options options; 112 113 /* optional user configfile */ 114 char *config = NULL; 115 116 /* 117 * Name of the host we are connecting to. This is the name given on the 118 * command line, or the HostName specified for the user-supplied name in a 119 * configuration file. 120 */ 121 char *host; 122 123 /* socket address the host resolves to */ 124 struct sockaddr_storage hostaddr; 125 126 /* Private host keys. */ 127 Sensitive sensitive_data; 128 129 /* Original real UID. */ 130 uid_t original_real_uid; 131 uid_t original_effective_uid; 132 133 /* command to be executed */ 134 Buffer command; 135 136 /* Should we execute a command or invoke a subsystem? */ 137 int subsystem_flag = 0; 138 139 /* # of replies received for global requests */ 140 static int client_global_request_id = 0; 141 142 /* pid of proxycommand child process */ 143 pid_t proxy_command_pid = 0; 144 145 /* Prints a help message to the user. This function never returns. */ 146 147 static void 148 usage(void) 149 { 150 fprintf(stderr, "Usage: %s [options] host [command]\n", __progname); 151 fprintf(stderr, "Options:\n"); 152 fprintf(stderr, " -l user Log in using this user name.\n"); 153 fprintf(stderr, " -n Redirect input from " _PATH_DEVNULL ".\n"); 154 fprintf(stderr, " -F config Config file (default: ~/%s).\n", 155 _PATH_SSH_USER_CONFFILE); 156 fprintf(stderr, " -A Enable authentication agent forwarding.\n"); 157 fprintf(stderr, " -a Disable authentication agent forwarding (default).\n"); 158 fprintf(stderr, " -X Enable X11 connection forwarding.\n"); 159 fprintf(stderr, " -Y Enable trusted X11 connection forwarding.\n"); 160 fprintf(stderr, " -x Disable X11 connection forwarding (default).\n"); 161 fprintf(stderr, " -i file Identity for public key authentication " 162 "(default: ~/.ssh/identity)\n"); 163 #ifdef SMARTCARD 164 fprintf(stderr, " -I reader Set smartcard reader.\n"); 165 #endif 166 fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n"); 167 fprintf(stderr, " -T Do not allocate a tty.\n"); 168 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); 169 fprintf(stderr, " Multiple -v increases verbosity.\n"); 170 fprintf(stderr, " -V Display version number only.\n"); 171 fprintf(stderr, " -q Quiet; don't display any warning messages.\n"); 172 fprintf(stderr, " -f Fork into background after authentication.\n"); 173 fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n"); 174 175 fprintf(stderr, " -c cipher Select encryption algorithm\n"); 176 fprintf(stderr, " -m macs Specify MAC algorithms for protocol version 2.\n"); 177 fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n"); 178 fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n"); 179 fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n"); 180 fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname); 181 fprintf(stderr, " forward them to the other side by connecting to host:port.\n"); 182 fprintf(stderr, " -D port Enable dynamic application-level port forwarding.\n"); 183 fprintf(stderr, " -C Enable compression.\n"); 184 fprintf(stderr, " -N Do not execute a shell or command.\n"); 185 fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n"); 186 fprintf(stderr, " -1 Force protocol version 1.\n"); 187 fprintf(stderr, " -2 Force protocol version 2.\n"); 188 fprintf(stderr, " -4 Use IPv4 only.\n"); 189 fprintf(stderr, " -6 Use IPv6 only.\n"); 190 fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n"); 191 fprintf(stderr, " -s Invoke command (mandatory) as SSH2 subsystem.\n"); 192 fprintf(stderr, " -b addr Local IP address.\n"); 193 exit(1); 194 } 195 196 static int ssh_session(void); 197 static int ssh_session2(void); 198 static void load_public_identity_files(void); 199 200 /* 201 * Main program for the ssh client. 202 */ 203 int 204 main(int ac, char **av) 205 { 206 int i, opt, exit_status; 207 u_short fwd_port, fwd_host_port; 208 char sfwd_port[6], sfwd_host_port[6]; 209 char *p, *cp, *line, buf[256]; 210 struct stat st; 211 struct passwd *pw; 212 int dummy; 213 extern int optind, optreset; 214 extern char *optarg; 215 216 __progname = ssh_get_progname(av[0]); 217 init_rng(); 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 #ifdef HAVE_SETRLIMIT 236 /* If we are installed setuid root be careful to not drop core. */ 237 if (original_real_uid != original_effective_uid) { 238 struct rlimit rlim; 239 rlim.rlim_cur = rlim.rlim_max = 0; 240 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 241 fatal("setrlimit failed: %.100s", strerror(errno)); 242 } 243 #endif 244 /* Get user data. */ 245 pw = getpwuid(original_real_uid); 246 if (!pw) { 247 logit("You don't exist, go away!"); 248 exit(1); 249 } 250 /* Take a copy of the returned structure. */ 251 pw = pwcopy(pw); 252 253 /* 254 * Set our umask to something reasonable, as some files are created 255 * with the default umask. This will make them world-readable but 256 * writable only by the owner, which is ok for all files for which we 257 * don't set the modes explicitly. 258 */ 259 umask(022); 260 261 /* Initialize option structure to indicate that no values have been set. */ 262 initialize_options(&options); 263 264 /* Parse command-line arguments. */ 265 host = NULL; 266 267 again: 268 while ((opt = getopt(ac, av, 269 "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:NPR:TVXY")) != -1) { 270 switch (opt) { 271 case '1': 272 options.protocol = SSH_PROTO_1; 273 break; 274 case '2': 275 options.protocol = SSH_PROTO_2; 276 break; 277 case '4': 278 options.address_family = AF_INET; 279 break; 280 case '6': 281 options.address_family = AF_INET6; 282 break; 283 case 'n': 284 stdin_null_flag = 1; 285 break; 286 case 'f': 287 fork_after_authentication_flag = 1; 288 stdin_null_flag = 1; 289 break; 290 case 'x': 291 options.forward_x11 = 0; 292 break; 293 case 'X': 294 options.forward_x11 = 1; 295 break; 296 case 'Y': 297 options.forward_x11 = 1; 298 options.forward_x11_trusted = 1; 299 break; 300 case 'g': 301 options.gateway_ports = 1; 302 break; 303 case 'P': /* deprecated */ 304 options.use_privileged_port = 0; 305 break; 306 case 'a': 307 options.forward_agent = 0; 308 break; 309 case 'A': 310 options.forward_agent = 1; 311 break; 312 case 'k': 313 options.gss_deleg_creds = 0; 314 break; 315 case 'i': 316 if (stat(optarg, &st) < 0) { 317 fprintf(stderr, "Warning: Identity file %s " 318 "does not exist.\n", optarg); 319 break; 320 } 321 if (options.num_identity_files >= 322 SSH_MAX_IDENTITY_FILES) 323 fatal("Too many identity files specified " 324 "(max %d)", SSH_MAX_IDENTITY_FILES); 325 options.identity_files[options.num_identity_files++] = 326 xstrdup(optarg); 327 break; 328 case 'I': 329 #ifdef SMARTCARD 330 options.smartcard_device = xstrdup(optarg); 331 #else 332 fprintf(stderr, "no support for smartcards.\n"); 333 #endif 334 break; 335 case 't': 336 if (tty_flag) 337 force_tty_flag = 1; 338 tty_flag = 1; 339 break; 340 case 'v': 341 if (debug_flag == 0) { 342 debug_flag = 1; 343 options.log_level = SYSLOG_LEVEL_DEBUG1; 344 } else { 345 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 346 options.log_level++; 347 break; 348 } 349 /* fallthrough */ 350 case 'V': 351 fprintf(stderr, 352 "%s, SSH protocols %d.%d/%d.%d, %s\n", 353 SSH_VERSION, 354 PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1, 355 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, 356 SSLeay_version(SSLEAY_VERSION)); 357 if (opt == 'V') 358 exit(0); 359 break; 360 case 'q': 361 options.log_level = SYSLOG_LEVEL_QUIET; 362 break; 363 case 'e': 364 if (optarg[0] == '^' && optarg[2] == 0 && 365 (u_char) optarg[1] >= 64 && 366 (u_char) optarg[1] < 128) 367 options.escape_char = (u_char) optarg[1] & 31; 368 else if (strlen(optarg) == 1) 369 options.escape_char = (u_char) optarg[0]; 370 else if (strcmp(optarg, "none") == 0) 371 options.escape_char = SSH_ESCAPECHAR_NONE; 372 else { 373 fprintf(stderr, "Bad escape character '%s'.\n", 374 optarg); 375 exit(1); 376 } 377 break; 378 case 'c': 379 if (ciphers_valid(optarg)) { 380 /* SSH2 only */ 381 options.ciphers = xstrdup(optarg); 382 options.cipher = SSH_CIPHER_ILLEGAL; 383 } else { 384 /* SSH1 only */ 385 options.cipher = cipher_number(optarg); 386 if (options.cipher == -1) { 387 fprintf(stderr, 388 "Unknown cipher type '%s'\n", 389 optarg); 390 exit(1); 391 } 392 if (options.cipher == SSH_CIPHER_3DES) 393 options.ciphers = "3des-cbc"; 394 else if (options.cipher == SSH_CIPHER_BLOWFISH) 395 options.ciphers = "blowfish-cbc"; 396 else 397 options.ciphers = (char *)-1; 398 } 399 break; 400 case 'm': 401 if (mac_valid(optarg)) 402 options.macs = xstrdup(optarg); 403 else { 404 fprintf(stderr, "Unknown mac type '%s'\n", 405 optarg); 406 exit(1); 407 } 408 break; 409 case 'p': 410 options.port = a2port(optarg); 411 if (options.port == 0) { 412 fprintf(stderr, "Bad port '%s'\n", optarg); 413 exit(1); 414 } 415 break; 416 case 'l': 417 options.user = optarg; 418 break; 419 420 case 'L': 421 case 'R': 422 if (sscanf(optarg, "%5[0123456789]:%255[^:]:%5[0123456789]", 423 sfwd_port, buf, sfwd_host_port) != 3 && 424 sscanf(optarg, "%5[0123456789]/%255[^/]/%5[0123456789]", 425 sfwd_port, buf, sfwd_host_port) != 3) { 426 fprintf(stderr, 427 "Bad forwarding specification '%s'\n", 428 optarg); 429 usage(); 430 /* NOTREACHED */ 431 } 432 if ((fwd_port = a2port(sfwd_port)) == 0 || 433 (fwd_host_port = a2port(sfwd_host_port)) == 0) { 434 fprintf(stderr, 435 "Bad forwarding port(s) '%s'\n", optarg); 436 exit(1); 437 } 438 if (opt == 'L') 439 add_local_forward(&options, fwd_port, buf, 440 fwd_host_port); 441 else if (opt == 'R') 442 add_remote_forward(&options, fwd_port, buf, 443 fwd_host_port); 444 break; 445 446 case 'D': 447 fwd_port = a2port(optarg); 448 if (fwd_port == 0) { 449 fprintf(stderr, "Bad dynamic port '%s'\n", 450 optarg); 451 exit(1); 452 } 453 add_local_forward(&options, fwd_port, "socks", 0); 454 break; 455 456 case 'C': 457 options.compression = 1; 458 break; 459 case 'N': 460 no_shell_flag = 1; 461 no_tty_flag = 1; 462 break; 463 case 'T': 464 no_tty_flag = 1; 465 break; 466 case 'o': 467 dummy = 1; 468 line = xstrdup(optarg); 469 if (process_config_line(&options, host ? host : "", 470 line, "command-line", 0, &dummy) != 0) 471 exit(1); 472 xfree(line); 473 break; 474 case 's': 475 subsystem_flag = 1; 476 break; 477 case 'b': 478 options.bind_address = optarg; 479 break; 480 case 'F': 481 config = optarg; 482 break; 483 default: 484 usage(); 485 } 486 } 487 488 ac -= optind; 489 av += optind; 490 491 if (ac > 0 && !host && **av != '-') { 492 if (strrchr(*av, '@')) { 493 p = xstrdup(*av); 494 cp = strrchr(p, '@'); 495 if (cp == NULL || cp == p) 496 usage(); 497 options.user = p; 498 *cp = '\0'; 499 host = ++cp; 500 } else 501 host = *av; 502 if (ac > 1) { 503 optind = optreset = 1; 504 goto again; 505 } 506 ac--, av++; 507 } 508 509 /* Check that we got a host name. */ 510 if (!host) 511 usage(); 512 513 SSLeay_add_all_algorithms(); 514 ERR_load_crypto_strings(); 515 516 /* Initialize the command to execute on remote host. */ 517 buffer_init(&command); 518 519 /* 520 * Save the command to execute on the remote host in a buffer. There 521 * is no limit on the length of the command, except by the maximum 522 * packet size. Also sets the tty flag if there is no command. 523 */ 524 if (!ac) { 525 /* No command specified - execute shell on a tty. */ 526 tty_flag = 1; 527 if (subsystem_flag) { 528 fprintf(stderr, 529 "You must specify a subsystem to invoke.\n"); 530 usage(); 531 } 532 } else { 533 /* A command has been specified. Store it into the buffer. */ 534 for (i = 0; i < ac; i++) { 535 if (i) 536 buffer_append(&command, " ", 1); 537 buffer_append(&command, av[i], strlen(av[i])); 538 } 539 } 540 541 /* Cannot fork to background if no command. */ 542 if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag) 543 fatal("Cannot fork into background without a command to execute."); 544 545 /* Allocate a tty by default if no command specified. */ 546 if (buffer_len(&command) == 0) 547 tty_flag = 1; 548 549 /* Force no tty */ 550 if (no_tty_flag) 551 tty_flag = 0; 552 /* Do not allocate a tty if stdin is not a tty. */ 553 if (!isatty(fileno(stdin)) && !force_tty_flag) { 554 if (tty_flag) 555 logit("Pseudo-terminal will not be allocated because stdin is not a terminal."); 556 tty_flag = 0; 557 } 558 559 /* 560 * Initialize "log" output. Since we are the client all output 561 * actually goes to stderr. 562 */ 563 log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 564 SYSLOG_FACILITY_USER, 1); 565 566 /* 567 * Read per-user configuration file. Ignore the system wide config 568 * file if the user specifies a config file on the command line. 569 */ 570 if (config != NULL) { 571 if (!read_config_file(config, host, &options)) 572 fatal("Can't open user config file %.100s: " 573 "%.100s", config, strerror(errno)); 574 } else { 575 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, 576 _PATH_SSH_USER_CONFFILE); 577 (void)read_config_file(buf, host, &options); 578 579 /* Read systemwide configuration file after use config. */ 580 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, &options); 581 } 582 583 /* Fill configuration defaults. */ 584 fill_default_options(&options); 585 586 channel_set_af(options.address_family); 587 588 /* reinit */ 589 log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1); 590 591 seed_rng(); 592 593 if (options.user == NULL) 594 options.user = xstrdup(pw->pw_name); 595 596 if (options.hostname != NULL) 597 host = options.hostname; 598 599 /* Find canonic host name. */ 600 if (strchr(host, '.') == 0) { 601 struct addrinfo hints; 602 struct addrinfo *ai = NULL; 603 int errgai; 604 memset(&hints, 0, sizeof(hints)); 605 hints.ai_family = options.address_family; 606 hints.ai_flags = AI_CANONNAME; 607 hints.ai_socktype = SOCK_STREAM; 608 errgai = getaddrinfo(host, NULL, &hints, &ai); 609 if (errgai == 0) { 610 if (ai->ai_canonname != NULL) 611 host = xstrdup(ai->ai_canonname); 612 freeaddrinfo(ai); 613 } 614 } 615 616 /* force lowercase for hostkey matching */ 617 if (options.host_key_alias != NULL) { 618 for (p = options.host_key_alias; *p; p++) 619 if (isupper(*p)) 620 *p = tolower(*p); 621 } 622 623 if (options.proxy_command != NULL && 624 strcmp(options.proxy_command, "none") == 0) 625 options.proxy_command = NULL; 626 627 /* Open a connection to the remote host. */ 628 if (ssh_connect(host, &hostaddr, options.port, 629 options.address_family, options.connection_attempts, 630 #ifdef HAVE_CYGWIN 631 options.use_privileged_port, 632 #else 633 original_effective_uid == 0 && options.use_privileged_port, 634 #endif 635 options.proxy_command) != 0) 636 exit(1); 637 638 /* 639 * If we successfully made the connection, load the host private key 640 * in case we will need it later for combined rsa-rhosts 641 * authentication. This must be done before releasing extra 642 * privileges, because the file is only readable by root. 643 * If we cannot access the private keys, load the public keys 644 * instead and try to execute the ssh-keysign helper instead. 645 */ 646 sensitive_data.nkeys = 0; 647 sensitive_data.keys = NULL; 648 sensitive_data.external_keysign = 0; 649 if (options.rhosts_rsa_authentication || 650 options.hostbased_authentication) { 651 sensitive_data.nkeys = 3; 652 sensitive_data.keys = xmalloc(sensitive_data.nkeys * 653 sizeof(Key)); 654 655 PRIV_START; 656 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 657 _PATH_HOST_KEY_FILE, "", NULL); 658 sensitive_data.keys[1] = key_load_private_type(KEY_DSA, 659 _PATH_HOST_DSA_KEY_FILE, "", NULL); 660 sensitive_data.keys[2] = key_load_private_type(KEY_RSA, 661 _PATH_HOST_RSA_KEY_FILE, "", NULL); 662 PRIV_END; 663 664 if (options.hostbased_authentication == 1 && 665 sensitive_data.keys[0] == NULL && 666 sensitive_data.keys[1] == NULL && 667 sensitive_data.keys[2] == NULL) { 668 sensitive_data.keys[1] = key_load_public( 669 _PATH_HOST_DSA_KEY_FILE, NULL); 670 sensitive_data.keys[2] = key_load_public( 671 _PATH_HOST_RSA_KEY_FILE, NULL); 672 sensitive_data.external_keysign = 1; 673 } 674 } 675 /* 676 * Get rid of any extra privileges that we may have. We will no 677 * longer need them. Also, extra privileges could make it very hard 678 * to read identity files and other non-world-readable files from the 679 * user's home directory if it happens to be on a NFS volume where 680 * root is mapped to nobody. 681 */ 682 seteuid(original_real_uid); 683 setuid(original_real_uid); 684 685 /* 686 * Now that we are back to our own permissions, create ~/.ssh 687 * directory if it doesn\'t already exist. 688 */ 689 snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 690 if (stat(buf, &st) < 0) 691 if (mkdir(buf, 0700) < 0) 692 error("Could not create directory '%.200s'.", buf); 693 694 /* load options.identity_files */ 695 load_public_identity_files(); 696 697 /* Expand ~ in known host file names. */ 698 /* XXX mem-leaks: */ 699 options.system_hostfile = 700 tilde_expand_filename(options.system_hostfile, original_real_uid); 701 options.user_hostfile = 702 tilde_expand_filename(options.user_hostfile, original_real_uid); 703 options.system_hostfile2 = 704 tilde_expand_filename(options.system_hostfile2, original_real_uid); 705 options.user_hostfile2 = 706 tilde_expand_filename(options.user_hostfile2, original_real_uid); 707 708 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 709 710 /* Log into the remote system. This never returns if the login fails. */ 711 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw); 712 713 /* We no longer need the private host keys. Clear them now. */ 714 if (sensitive_data.nkeys != 0) { 715 for (i = 0; i < sensitive_data.nkeys; i++) { 716 if (sensitive_data.keys[i] != NULL) { 717 /* Destroys contents safely */ 718 debug3("clear hostkey %d", i); 719 key_free(sensitive_data.keys[i]); 720 sensitive_data.keys[i] = NULL; 721 } 722 } 723 xfree(sensitive_data.keys); 724 } 725 for (i = 0; i < options.num_identity_files; i++) { 726 if (options.identity_files[i]) { 727 xfree(options.identity_files[i]); 728 options.identity_files[i] = NULL; 729 } 730 if (options.identity_keys[i]) { 731 key_free(options.identity_keys[i]); 732 options.identity_keys[i] = NULL; 733 } 734 } 735 736 exit_status = compat20 ? ssh_session2() : ssh_session(); 737 packet_close(); 738 739 /* 740 * Send SIGHUP to proxy command if used. We don't wait() in 741 * case it hangs and instead rely on init to reap the child 742 */ 743 if (proxy_command_pid > 1) 744 kill(proxy_command_pid, SIGHUP); 745 746 return exit_status; 747 } 748 749 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 750 751 static void 752 x11_get_proto(char **_proto, char **_data) 753 { 754 char cmd[1024]; 755 char line[512]; 756 char xdisplay[512]; 757 static char proto[512], data[512]; 758 FILE *f; 759 int got_data = 0, generated = 0, do_unlink = 0, i; 760 char *display, *xauthdir, *xauthfile; 761 struct stat st; 762 763 xauthdir = xauthfile = NULL; 764 *_proto = proto; 765 *_data = data; 766 proto[0] = data[0] = '\0'; 767 768 if (!options.xauth_location || 769 (stat(options.xauth_location, &st) == -1)) { 770 debug("No xauth program."); 771 } else { 772 if ((display = getenv("DISPLAY")) == NULL) { 773 debug("x11_get_proto: DISPLAY not set"); 774 return; 775 } 776 /* 777 * Handle FamilyLocal case where $DISPLAY does 778 * not match an authorization entry. For this we 779 * just try "xauth list unix:displaynum.screennum". 780 * XXX: "localhost" match to determine FamilyLocal 781 * is not perfect. 782 */ 783 if (strncmp(display, "localhost:", 10) == 0) { 784 snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 785 display + 10); 786 display = xdisplay; 787 } 788 if (options.forward_x11_trusted == 0) { 789 xauthdir = xmalloc(MAXPATHLEN); 790 xauthfile = xmalloc(MAXPATHLEN); 791 strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); 792 if (mkdtemp(xauthdir) != NULL) { 793 do_unlink = 1; 794 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile", 795 xauthdir); 796 snprintf(cmd, sizeof(cmd), 797 "%s -f %s generate %s " SSH_X11_PROTO 798 " untrusted timeout 120 2>" _PATH_DEVNULL, 799 options.xauth_location, xauthfile, display); 800 debug2("x11_get_proto: %s", cmd); 801 if (system(cmd) == 0) 802 generated = 1; 803 } 804 } 805 snprintf(cmd, sizeof(cmd), 806 "%s %s%s list %s . 2>" _PATH_DEVNULL, 807 options.xauth_location, 808 generated ? "-f " : "" , 809 generated ? xauthfile : "", 810 display); 811 debug2("x11_get_proto: %s", cmd); 812 f = popen(cmd, "r"); 813 if (f && fgets(line, sizeof(line), f) && 814 sscanf(line, "%*s %511s %511s", proto, data) == 2) 815 got_data = 1; 816 if (f) 817 pclose(f); 818 } 819 820 if (do_unlink) { 821 unlink(xauthfile); 822 rmdir(xauthdir); 823 } 824 if (xauthdir) 825 xfree(xauthdir); 826 if (xauthfile) 827 xfree(xauthfile); 828 829 /* 830 * If we didn't get authentication data, just make up some 831 * data. The forwarding code will check the validity of the 832 * response anyway, and substitute this data. The X11 833 * server, however, will ignore this fake data and use 834 * whatever authentication mechanisms it was using otherwise 835 * for the local connection. 836 */ 837 if (!got_data) { 838 u_int32_t rand = 0; 839 840 logit("Warning: No xauth data; " 841 "using fake authentication data for X11 forwarding."); 842 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 843 for (i = 0; i < 16; i++) { 844 if (i % 4 == 0) 845 rand = arc4random(); 846 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 847 rand & 0xff); 848 rand >>= 8; 849 } 850 } 851 } 852 853 static void 854 ssh_init_forwarding(void) 855 { 856 int success = 0; 857 int i; 858 859 /* Initiate local TCP/IP port forwardings. */ 860 for (i = 0; i < options.num_local_forwards; i++) { 861 debug("Connections to local port %d forwarded to remote address %.200s:%d", 862 options.local_forwards[i].port, 863 options.local_forwards[i].host, 864 options.local_forwards[i].host_port); 865 success += channel_setup_local_fwd_listener( 866 options.local_forwards[i].port, 867 options.local_forwards[i].host, 868 options.local_forwards[i].host_port, 869 options.gateway_ports); 870 } 871 if (i > 0 && success == 0) 872 error("Could not request local forwarding."); 873 874 /* Initiate remote TCP/IP port forwardings. */ 875 for (i = 0; i < options.num_remote_forwards; i++) { 876 debug("Connections to remote port %d forwarded to local address %.200s:%d", 877 options.remote_forwards[i].port, 878 options.remote_forwards[i].host, 879 options.remote_forwards[i].host_port); 880 channel_request_remote_forwarding( 881 options.remote_forwards[i].port, 882 options.remote_forwards[i].host, 883 options.remote_forwards[i].host_port); 884 } 885 } 886 887 static void 888 check_agent_present(void) 889 { 890 if (options.forward_agent) { 891 /* Clear agent forwarding if we don\'t have an agent. */ 892 if (!ssh_agent_present()) 893 options.forward_agent = 0; 894 } 895 } 896 897 static int 898 ssh_session(void) 899 { 900 int type; 901 int interactive = 0; 902 int have_tty = 0; 903 struct winsize ws; 904 char *cp; 905 906 /* Enable compression if requested. */ 907 if (options.compression) { 908 debug("Requesting compression at level %d.", options.compression_level); 909 910 if (options.compression_level < 1 || options.compression_level > 9) 911 fatal("Compression level must be from 1 (fast) to 9 (slow, best)."); 912 913 /* Send the request. */ 914 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 915 packet_put_int(options.compression_level); 916 packet_send(); 917 packet_write_wait(); 918 type = packet_read(); 919 if (type == SSH_SMSG_SUCCESS) 920 packet_start_compression(options.compression_level); 921 else if (type == SSH_SMSG_FAILURE) 922 logit("Warning: Remote host refused compression."); 923 else 924 packet_disconnect("Protocol error waiting for compression response."); 925 } 926 /* Allocate a pseudo tty if appropriate. */ 927 if (tty_flag) { 928 debug("Requesting pty."); 929 930 /* Start the packet. */ 931 packet_start(SSH_CMSG_REQUEST_PTY); 932 933 /* Store TERM in the packet. There is no limit on the 934 length of the string. */ 935 cp = getenv("TERM"); 936 if (!cp) 937 cp = ""; 938 packet_put_cstring(cp); 939 940 /* Store window size in the packet. */ 941 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 942 memset(&ws, 0, sizeof(ws)); 943 packet_put_int(ws.ws_row); 944 packet_put_int(ws.ws_col); 945 packet_put_int(ws.ws_xpixel); 946 packet_put_int(ws.ws_ypixel); 947 948 /* Store tty modes in the packet. */ 949 tty_make_modes(fileno(stdin), NULL); 950 951 /* Send the packet, and wait for it to leave. */ 952 packet_send(); 953 packet_write_wait(); 954 955 /* Read response from the server. */ 956 type = packet_read(); 957 if (type == SSH_SMSG_SUCCESS) { 958 interactive = 1; 959 have_tty = 1; 960 } else if (type == SSH_SMSG_FAILURE) 961 logit("Warning: Remote host failed or refused to allocate a pseudo tty."); 962 else 963 packet_disconnect("Protocol error waiting for pty request response."); 964 } 965 /* Request X11 forwarding if enabled and DISPLAY is set. */ 966 if (options.forward_x11 && getenv("DISPLAY") != NULL) { 967 char *proto, *data; 968 /* Get reasonable local authentication information. */ 969 x11_get_proto(&proto, &data); 970 /* Request forwarding with authentication spoofing. */ 971 debug("Requesting X11 forwarding with authentication spoofing."); 972 x11_request_forwarding_with_spoofing(0, proto, data); 973 974 /* Read response from the server. */ 975 type = packet_read(); 976 if (type == SSH_SMSG_SUCCESS) { 977 interactive = 1; 978 } else if (type == SSH_SMSG_FAILURE) { 979 logit("Warning: Remote host denied X11 forwarding."); 980 } else { 981 packet_disconnect("Protocol error waiting for X11 forwarding"); 982 } 983 } 984 /* Tell the packet module whether this is an interactive session. */ 985 packet_set_interactive(interactive); 986 987 /* Request authentication agent forwarding if appropriate. */ 988 check_agent_present(); 989 990 if (options.forward_agent) { 991 debug("Requesting authentication agent forwarding."); 992 auth_request_forwarding(); 993 994 /* Read response from the server. */ 995 type = packet_read(); 996 packet_check_eom(); 997 if (type != SSH_SMSG_SUCCESS) 998 logit("Warning: Remote host denied authentication agent forwarding."); 999 } 1000 1001 /* Initiate port forwardings. */ 1002 ssh_init_forwarding(); 1003 1004 /* If requested, let ssh continue in the background. */ 1005 if (fork_after_authentication_flag) 1006 if (daemon(1, 1) < 0) 1007 fatal("daemon() failed: %.200s", strerror(errno)); 1008 1009 /* 1010 * If a command was specified on the command line, execute the 1011 * command now. Otherwise request the server to start a shell. 1012 */ 1013 if (buffer_len(&command) > 0) { 1014 int len = buffer_len(&command); 1015 if (len > 900) 1016 len = 900; 1017 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command)); 1018 packet_start(SSH_CMSG_EXEC_CMD); 1019 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1020 packet_send(); 1021 packet_write_wait(); 1022 } else { 1023 debug("Requesting shell."); 1024 packet_start(SSH_CMSG_EXEC_SHELL); 1025 packet_send(); 1026 packet_write_wait(); 1027 } 1028 1029 /* Enter the interactive session. */ 1030 return client_loop(have_tty, tty_flag ? 1031 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1032 } 1033 1034 static void 1035 client_subsystem_reply(int type, u_int32_t seq, void *ctxt) 1036 { 1037 int id, len; 1038 1039 id = packet_get_int(); 1040 len = buffer_len(&command); 1041 if (len > 900) 1042 len = 900; 1043 packet_check_eom(); 1044 if (type == SSH2_MSG_CHANNEL_FAILURE) 1045 fatal("Request for subsystem '%.*s' failed on channel %d", 1046 len, (u_char *)buffer_ptr(&command), id); 1047 } 1048 1049 void 1050 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt) 1051 { 1052 int i; 1053 1054 i = client_global_request_id++; 1055 if (i >= options.num_remote_forwards) 1056 return; 1057 debug("remote forward %s for: listen %d, connect %s:%d", 1058 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 1059 options.remote_forwards[i].port, 1060 options.remote_forwards[i].host, 1061 options.remote_forwards[i].host_port); 1062 if (type == SSH2_MSG_REQUEST_FAILURE) 1063 logit("Warning: remote port forwarding failed for listen port %d", 1064 options.remote_forwards[i].port); 1065 } 1066 1067 /* request pty/x11/agent/tcpfwd/shell for channel */ 1068 static void 1069 ssh_session2_setup(int id, void *arg) 1070 { 1071 int len; 1072 int interactive = 0; 1073 struct termios tio; 1074 1075 debug2("ssh_session2_setup: id %d", id); 1076 1077 if (tty_flag) { 1078 struct winsize ws; 1079 char *cp; 1080 cp = getenv("TERM"); 1081 if (!cp) 1082 cp = ""; 1083 /* Store window size in the packet. */ 1084 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1085 memset(&ws, 0, sizeof(ws)); 1086 1087 channel_request_start(id, "pty-req", 0); 1088 packet_put_cstring(cp); 1089 packet_put_int(ws.ws_col); 1090 packet_put_int(ws.ws_row); 1091 packet_put_int(ws.ws_xpixel); 1092 packet_put_int(ws.ws_ypixel); 1093 tio = get_saved_tio(); 1094 tty_make_modes(/*ignored*/ 0, &tio); 1095 packet_send(); 1096 interactive = 1; 1097 /* XXX wait for reply */ 1098 } 1099 if (options.forward_x11 && 1100 getenv("DISPLAY") != NULL) { 1101 char *proto, *data; 1102 /* Get reasonable local authentication information. */ 1103 x11_get_proto(&proto, &data); 1104 /* Request forwarding with authentication spoofing. */ 1105 debug("Requesting X11 forwarding with authentication spoofing."); 1106 x11_request_forwarding_with_spoofing(id, proto, data); 1107 interactive = 1; 1108 /* XXX wait for reply */ 1109 } 1110 1111 check_agent_present(); 1112 if (options.forward_agent) { 1113 debug("Requesting authentication agent forwarding."); 1114 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1115 packet_send(); 1116 } 1117 1118 len = buffer_len(&command); 1119 if (len > 0) { 1120 if (len > 900) 1121 len = 900; 1122 if (subsystem_flag) { 1123 debug("Sending subsystem: %.*s", len, (u_char *)buffer_ptr(&command)); 1124 channel_request_start(id, "subsystem", /*want reply*/ 1); 1125 /* register callback for reply */ 1126 /* XXX we assume that client_loop has already been called */ 1127 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply); 1128 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply); 1129 } else { 1130 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command)); 1131 channel_request_start(id, "exec", 0); 1132 } 1133 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1134 packet_send(); 1135 } else { 1136 channel_request_start(id, "shell", 0); 1137 packet_send(); 1138 } 1139 1140 packet_set_interactive(interactive); 1141 } 1142 1143 /* open new channel for a session */ 1144 static int 1145 ssh_session2_open(void) 1146 { 1147 Channel *c; 1148 int window, packetmax, in, out, err; 1149 1150 if (stdin_null_flag) { 1151 in = open(_PATH_DEVNULL, O_RDONLY); 1152 } else { 1153 in = dup(STDIN_FILENO); 1154 } 1155 out = dup(STDOUT_FILENO); 1156 err = dup(STDERR_FILENO); 1157 1158 if (in < 0 || out < 0 || err < 0) 1159 fatal("dup() in/out/err failed"); 1160 1161 /* enable nonblocking unless tty */ 1162 if (!isatty(in)) 1163 set_nonblock(in); 1164 if (!isatty(out)) 1165 set_nonblock(out); 1166 if (!isatty(err)) 1167 set_nonblock(err); 1168 1169 window = CHAN_SES_WINDOW_DEFAULT; 1170 packetmax = CHAN_SES_PACKET_DEFAULT; 1171 if (tty_flag) { 1172 window >>= 1; 1173 packetmax >>= 1; 1174 } 1175 c = channel_new( 1176 "session", SSH_CHANNEL_OPENING, in, out, err, 1177 window, packetmax, CHAN_EXTENDED_WRITE, 1178 "client-session", /*nonblock*/0); 1179 1180 debug3("ssh_session2_open: channel_new: %d", c->self); 1181 1182 channel_send_open(c->self); 1183 if (!no_shell_flag) 1184 channel_register_confirm(c->self, ssh_session2_setup); 1185 1186 return c->self; 1187 } 1188 1189 static int 1190 ssh_session2(void) 1191 { 1192 int id = -1; 1193 1194 /* XXX should be pre-session */ 1195 ssh_init_forwarding(); 1196 1197 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1198 id = ssh_session2_open(); 1199 1200 /* If requested, let ssh continue in the background. */ 1201 if (fork_after_authentication_flag) 1202 if (daemon(1, 1) < 0) 1203 fatal("daemon() failed: %.200s", strerror(errno)); 1204 1205 return client_loop(tty_flag, tty_flag ? 1206 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1207 } 1208 1209 static void 1210 load_public_identity_files(void) 1211 { 1212 char *filename; 1213 int i = 0; 1214 Key *public; 1215 #ifdef SMARTCARD 1216 Key **keys; 1217 1218 if (options.smartcard_device != NULL && 1219 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1220 (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL ) { 1221 int count = 0; 1222 for (i = 0; keys[i] != NULL; i++) { 1223 count++; 1224 memmove(&options.identity_files[1], &options.identity_files[0], 1225 sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1)); 1226 memmove(&options.identity_keys[1], &options.identity_keys[0], 1227 sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1)); 1228 options.num_identity_files++; 1229 options.identity_keys[0] = keys[i]; 1230 options.identity_files[0] = sc_get_key_label(keys[i]); 1231 } 1232 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES) 1233 options.num_identity_files = SSH_MAX_IDENTITY_FILES; 1234 i = count; 1235 xfree(keys); 1236 } 1237 #endif /* SMARTCARD */ 1238 for (; i < options.num_identity_files; i++) { 1239 filename = tilde_expand_filename(options.identity_files[i], 1240 original_real_uid); 1241 public = key_load_public(filename, NULL); 1242 debug("identity file %s type %d", filename, 1243 public ? public->type : -1); 1244 xfree(options.identity_files[i]); 1245 options.identity_files[i] = filename; 1246 options.identity_keys[i] = public; 1247 } 1248 } 1249