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 45 #include <openssl/evp.h> 46 #include <openssl/err.h> 47 48 #include "ssh.h" 49 #include "ssh1.h" 50 #include "ssh2.h" 51 #include "compat.h" 52 #include "cipher.h" 53 #include "xmalloc.h" 54 #include "packet.h" 55 #include "buffer.h" 56 #include "channels.h" 57 #include "key.h" 58 #include "authfd.h" 59 #include "authfile.h" 60 #include "pathnames.h" 61 #include "clientloop.h" 62 #include "log.h" 63 #include "readconf.h" 64 #include "sshconnect.h" 65 #include "tildexpand.h" 66 #include "dispatch.h" 67 #include "misc.h" 68 #include "kex.h" 69 #include "mac.h" 70 #include "sshtty.h" 71 72 #ifdef SMARTCARD 73 #include "scard.h" 74 #endif 75 76 extern char *__progname; 77 78 /* Flag indicating whether debug mode is on. This can be set on the command line. */ 79 int debug_flag = 0; 80 81 /* Flag indicating whether a tty should be allocated */ 82 int tty_flag = 0; 83 int no_tty_flag = 0; 84 int force_tty_flag = 0; 85 86 /* don't exec a shell */ 87 int no_shell_flag = 0; 88 89 /* 90 * Flag indicating that nothing should be read from stdin. This can be set 91 * on the command line. 92 */ 93 int stdin_null_flag = 0; 94 95 /* 96 * Flag indicating that ssh should fork after authentication. This is useful 97 * so that the passphrase can be entered manually, and then ssh goes to the 98 * background. 99 */ 100 int fork_after_authentication_flag = 0; 101 102 /* 103 * General data structure for command line options and options configurable 104 * in configuration files. See readconf.h. 105 */ 106 Options options; 107 108 /* optional user configfile */ 109 char *config = NULL; 110 111 /* 112 * Name of the host we are connecting to. This is the name given on the 113 * command line, or the HostName specified for the user-supplied name in a 114 * configuration file. 115 */ 116 char *host; 117 118 /* socket address the host resolves to */ 119 struct sockaddr_storage hostaddr; 120 121 /* Private host keys. */ 122 Sensitive sensitive_data; 123 124 /* Original real UID. */ 125 uid_t original_real_uid; 126 uid_t original_effective_uid; 127 128 /* command to be executed */ 129 Buffer command; 130 131 /* Should we execute a command or invoke a subsystem? */ 132 int subsystem_flag = 0; 133 134 /* # of replies received for global requests */ 135 static int client_global_request_id = 0; 136 137 /* pid of proxycommand child process */ 138 pid_t proxy_command_pid = 0; 139 140 /* Prints a help message to the user. This function never returns. */ 141 142 static void 143 usage(void) 144 { 145 fprintf(stderr, "Usage: %s [options] host [command]\n", __progname); 146 fprintf(stderr, "Options:\n"); 147 fprintf(stderr, " -l user Log in using this user name.\n"); 148 fprintf(stderr, " -n Redirect input from " _PATH_DEVNULL ".\n"); 149 fprintf(stderr, " -F config Config file (default: ~/%s).\n", 150 _PATH_SSH_USER_CONFFILE); 151 fprintf(stderr, " -A Enable authentication agent forwarding.\n"); 152 fprintf(stderr, " -a Disable authentication agent forwarding (default).\n"); 153 fprintf(stderr, " -X Enable X11 connection forwarding.\n"); 154 fprintf(stderr, " -Y Enable trusted X11 connection forwarding.\n"); 155 fprintf(stderr, " -x Disable X11 connection forwarding (default).\n"); 156 fprintf(stderr, " -i file Identity for public key authentication " 157 "(default: ~/.ssh/identity)\n"); 158 #ifdef SMARTCARD 159 fprintf(stderr, " -I reader Set smartcard reader.\n"); 160 #endif 161 fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n"); 162 fprintf(stderr, " -T Do not allocate a tty.\n"); 163 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); 164 fprintf(stderr, " Multiple -v increases verbosity.\n"); 165 fprintf(stderr, " -V Display version number only.\n"); 166 fprintf(stderr, " -q Quiet; don't display any warning messages.\n"); 167 fprintf(stderr, " -f Fork into background after authentication.\n"); 168 fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n"); 169 170 fprintf(stderr, " -c cipher Select encryption algorithm\n"); 171 fprintf(stderr, " -m macs Specify MAC algorithms for protocol version 2.\n"); 172 fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n"); 173 fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n"); 174 fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n"); 175 fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname); 176 fprintf(stderr, " forward them to the other side by connecting to host:port.\n"); 177 fprintf(stderr, " -D port Enable dynamic application-level port forwarding.\n"); 178 fprintf(stderr, " -C Enable compression.\n"); 179 fprintf(stderr, " -N Do not execute a shell or command.\n"); 180 fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n"); 181 fprintf(stderr, " -1 Force protocol version 1.\n"); 182 fprintf(stderr, " -2 Force protocol version 2.\n"); 183 fprintf(stderr, " -4 Use IPv4 only.\n"); 184 fprintf(stderr, " -6 Use IPv6 only.\n"); 185 fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n"); 186 fprintf(stderr, " -s Invoke command (mandatory) as SSH2 subsystem.\n"); 187 fprintf(stderr, " -b addr Local IP address.\n"); 188 exit(1); 189 } 190 191 static int ssh_session(void); 192 static int ssh_session2(void); 193 static void load_public_identity_files(void); 194 195 /* 196 * Main program for the ssh client. 197 */ 198 int 199 main(int ac, char **av) 200 { 201 int i, opt, exit_status; 202 u_short fwd_port, fwd_host_port; 203 char sfwd_port[6], sfwd_host_port[6]; 204 char *p, *cp, *line, buf[256]; 205 struct stat st; 206 struct passwd *pw; 207 int dummy; 208 extern int optind, optreset; 209 extern char *optarg; 210 211 /* 212 * Save the original real uid. It will be needed later (uid-swapping 213 * may clobber the real uid). 214 */ 215 original_real_uid = getuid(); 216 original_effective_uid = geteuid(); 217 218 /* 219 * Use uid-swapping to give up root privileges for the duration of 220 * option processing. We will re-instantiate the rights when we are 221 * ready to create the privileged port, and will permanently drop 222 * them when the port has been created (actually, when the connection 223 * has been made, as we may need to create the port several times). 224 */ 225 PRIV_END; 226 227 /* If we are installed setuid root be careful to not drop core. */ 228 if (original_real_uid != original_effective_uid) { 229 struct rlimit rlim; 230 rlim.rlim_cur = rlim.rlim_max = 0; 231 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 232 fatal("setrlimit failed: %.100s", strerror(errno)); 233 } 234 /* Get user data. */ 235 pw = getpwuid(original_real_uid); 236 if (!pw) { 237 logit("You don't exist, go away!"); 238 exit(1); 239 } 240 /* Take a copy of the returned structure. */ 241 pw = pwcopy(pw); 242 243 /* 244 * Set our umask to something reasonable, as some files are created 245 * with the default umask. This will make them world-readable but 246 * writable only by the owner, which is ok for all files for which we 247 * don't set the modes explicitly. 248 */ 249 umask(022); 250 251 /* Initialize option structure to indicate that no values have been set. */ 252 initialize_options(&options); 253 254 /* Parse command-line arguments. */ 255 host = NULL; 256 257 again: 258 while ((opt = getopt(ac, av, 259 "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:NPR:TVXY")) != -1) { 260 switch (opt) { 261 case '1': 262 options.protocol = SSH_PROTO_1; 263 break; 264 case '2': 265 options.protocol = SSH_PROTO_2; 266 break; 267 case '4': 268 options.address_family = AF_INET; 269 break; 270 case '6': 271 options.address_family = AF_INET6; 272 break; 273 case 'n': 274 stdin_null_flag = 1; 275 break; 276 case 'f': 277 fork_after_authentication_flag = 1; 278 stdin_null_flag = 1; 279 break; 280 case 'x': 281 options.forward_x11 = 0; 282 break; 283 case 'X': 284 options.forward_x11 = 1; 285 break; 286 case 'Y': 287 options.forward_x11 = 1; 288 options.forward_x11_trusted = 1; 289 break; 290 case 'g': 291 options.gateway_ports = 1; 292 break; 293 case 'P': /* deprecated */ 294 options.use_privileged_port = 0; 295 break; 296 case 'a': 297 options.forward_agent = 0; 298 break; 299 case 'A': 300 options.forward_agent = 1; 301 break; 302 case 'k': 303 options.gss_deleg_creds = 0; 304 break; 305 case 'i': 306 if (stat(optarg, &st) < 0) { 307 fprintf(stderr, "Warning: Identity file %s " 308 "does not exist.\n", optarg); 309 break; 310 } 311 if (options.num_identity_files >= 312 SSH_MAX_IDENTITY_FILES) 313 fatal("Too many identity files specified " 314 "(max %d)", SSH_MAX_IDENTITY_FILES); 315 options.identity_files[options.num_identity_files++] = 316 xstrdup(optarg); 317 break; 318 case 'I': 319 #ifdef SMARTCARD 320 options.smartcard_device = xstrdup(optarg); 321 #else 322 fprintf(stderr, "no support for smartcards.\n"); 323 #endif 324 break; 325 case 't': 326 if (tty_flag) 327 force_tty_flag = 1; 328 tty_flag = 1; 329 break; 330 case 'v': 331 if (debug_flag == 0) { 332 debug_flag = 1; 333 options.log_level = SYSLOG_LEVEL_DEBUG1; 334 } else { 335 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 336 options.log_level++; 337 break; 338 } 339 /* fallthrough */ 340 case 'V': 341 fprintf(stderr, 342 "%s, SSH protocols %d.%d/%d.%d, %s\n", 343 SSH_VERSION, 344 PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1, 345 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, 346 SSLeay_version(SSLEAY_VERSION)); 347 if (opt == 'V') 348 exit(0); 349 break; 350 case 'q': 351 options.log_level = SYSLOG_LEVEL_QUIET; 352 break; 353 case 'e': 354 if (optarg[0] == '^' && optarg[2] == 0 && 355 (u_char) optarg[1] >= 64 && 356 (u_char) optarg[1] < 128) 357 options.escape_char = (u_char) optarg[1] & 31; 358 else if (strlen(optarg) == 1) 359 options.escape_char = (u_char) optarg[0]; 360 else if (strcmp(optarg, "none") == 0) 361 options.escape_char = SSH_ESCAPECHAR_NONE; 362 else { 363 fprintf(stderr, "Bad escape character '%s'.\n", 364 optarg); 365 exit(1); 366 } 367 break; 368 case 'c': 369 if (ciphers_valid(optarg)) { 370 /* SSH2 only */ 371 options.ciphers = xstrdup(optarg); 372 options.cipher = SSH_CIPHER_ILLEGAL; 373 } else { 374 /* SSH1 only */ 375 options.cipher = cipher_number(optarg); 376 if (options.cipher == -1) { 377 fprintf(stderr, 378 "Unknown cipher type '%s'\n", 379 optarg); 380 exit(1); 381 } 382 if (options.cipher == SSH_CIPHER_3DES) 383 options.ciphers = "3des-cbc"; 384 else if (options.cipher == SSH_CIPHER_BLOWFISH) 385 options.ciphers = "blowfish-cbc"; 386 else 387 options.ciphers = (char *)-1; 388 } 389 break; 390 case 'm': 391 if (mac_valid(optarg)) 392 options.macs = xstrdup(optarg); 393 else { 394 fprintf(stderr, "Unknown mac type '%s'\n", 395 optarg); 396 exit(1); 397 } 398 break; 399 case 'p': 400 options.port = a2port(optarg); 401 if (options.port == 0) { 402 fprintf(stderr, "Bad port '%s'\n", optarg); 403 exit(1); 404 } 405 break; 406 case 'l': 407 options.user = optarg; 408 break; 409 410 case 'L': 411 case 'R': 412 if (sscanf(optarg, "%5[0-9]:%255[^:]:%5[0-9]", 413 sfwd_port, buf, sfwd_host_port) != 3 && 414 sscanf(optarg, "%5[0-9]/%255[^/]/%5[0-9]", 415 sfwd_port, buf, sfwd_host_port) != 3) { 416 fprintf(stderr, 417 "Bad forwarding specification '%s'\n", 418 optarg); 419 usage(); 420 /* NOTREACHED */ 421 } 422 if ((fwd_port = a2port(sfwd_port)) == 0 || 423 (fwd_host_port = a2port(sfwd_host_port)) == 0) { 424 fprintf(stderr, 425 "Bad forwarding port(s) '%s'\n", optarg); 426 exit(1); 427 } 428 if (opt == 'L') 429 add_local_forward(&options, fwd_port, buf, 430 fwd_host_port); 431 else if (opt == 'R') 432 add_remote_forward(&options, fwd_port, buf, 433 fwd_host_port); 434 break; 435 436 case 'D': 437 fwd_port = a2port(optarg); 438 if (fwd_port == 0) { 439 fprintf(stderr, "Bad dynamic port '%s'\n", 440 optarg); 441 exit(1); 442 } 443 add_local_forward(&options, fwd_port, "socks", 0); 444 break; 445 446 case 'C': 447 options.compression = 1; 448 break; 449 case 'N': 450 no_shell_flag = 1; 451 no_tty_flag = 1; 452 break; 453 case 'T': 454 no_tty_flag = 1; 455 break; 456 case 'o': 457 dummy = 1; 458 line = xstrdup(optarg); 459 if (process_config_line(&options, host ? host : "", 460 line, "command-line", 0, &dummy) != 0) 461 exit(1); 462 xfree(line); 463 break; 464 case 's': 465 subsystem_flag = 1; 466 break; 467 case 'b': 468 options.bind_address = optarg; 469 break; 470 case 'F': 471 config = optarg; 472 break; 473 default: 474 usage(); 475 } 476 } 477 478 ac -= optind; 479 av += optind; 480 481 if (ac > 0 && !host && **av != '-') { 482 if (strrchr(*av, '@')) { 483 p = xstrdup(*av); 484 cp = strrchr(p, '@'); 485 if (cp == NULL || cp == p) 486 usage(); 487 options.user = p; 488 *cp = '\0'; 489 host = ++cp; 490 } else 491 host = *av; 492 if (ac > 1) { 493 optind = optreset = 1; 494 goto again; 495 } 496 ac--, av++; 497 } 498 499 /* Check that we got a host name. */ 500 if (!host) 501 usage(); 502 503 SSLeay_add_all_algorithms(); 504 ERR_load_crypto_strings(); 505 506 /* Initialize the command to execute on remote host. */ 507 buffer_init(&command); 508 509 /* 510 * Save the command to execute on the remote host in a buffer. There 511 * is no limit on the length of the command, except by the maximum 512 * packet size. Also sets the tty flag if there is no command. 513 */ 514 if (!ac) { 515 /* No command specified - execute shell on a tty. */ 516 tty_flag = 1; 517 if (subsystem_flag) { 518 fprintf(stderr, 519 "You must specify a subsystem to invoke.\n"); 520 usage(); 521 } 522 } else { 523 /* A command has been specified. Store it into the buffer. */ 524 for (i = 0; i < ac; i++) { 525 if (i) 526 buffer_append(&command, " ", 1); 527 buffer_append(&command, av[i], strlen(av[i])); 528 } 529 } 530 531 /* Cannot fork to background if no command. */ 532 if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag) 533 fatal("Cannot fork into background without a command to execute."); 534 535 /* Allocate a tty by default if no command specified. */ 536 if (buffer_len(&command) == 0) 537 tty_flag = 1; 538 539 /* Force no tty */ 540 if (no_tty_flag) 541 tty_flag = 0; 542 /* Do not allocate a tty if stdin is not a tty. */ 543 if (!isatty(fileno(stdin)) && !force_tty_flag) { 544 if (tty_flag) 545 logit("Pseudo-terminal will not be allocated because stdin is not a terminal."); 546 tty_flag = 0; 547 } 548 549 /* 550 * Initialize "log" output. Since we are the client all output 551 * actually goes to stderr. 552 */ 553 log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 554 SYSLOG_FACILITY_USER, 1); 555 556 /* 557 * Read per-user configuration file. Ignore the system wide config 558 * file if the user specifies a config file on the command line. 559 */ 560 if (config != NULL) { 561 if (!read_config_file(config, host, &options)) 562 fatal("Can't open user config file %.100s: " 563 "%.100s", config, strerror(errno)); 564 } else { 565 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, 566 _PATH_SSH_USER_CONFFILE); 567 (void)read_config_file(buf, host, &options); 568 569 /* Read systemwide configuration file after use config. */ 570 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, &options); 571 } 572 573 /* Fill configuration defaults. */ 574 fill_default_options(&options); 575 576 channel_set_af(options.address_family); 577 578 /* reinit */ 579 log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1); 580 581 if (options.user == NULL) 582 options.user = xstrdup(pw->pw_name); 583 584 if (options.hostname != NULL) 585 host = options.hostname; 586 587 /* force lowercase for hostkey matching */ 588 if (options.host_key_alias != NULL) { 589 for (p = options.host_key_alias; *p; p++) 590 if (isupper(*p)) 591 *p = tolower(*p); 592 } 593 594 if (options.proxy_command != NULL && 595 strcmp(options.proxy_command, "none") == 0) 596 options.proxy_command = NULL; 597 598 /* Open a connection to the remote host. */ 599 if (ssh_connect(host, &hostaddr, options.port, 600 options.address_family, options.connection_attempts, 601 original_effective_uid == 0 && options.use_privileged_port, 602 options.proxy_command) != 0) 603 exit(1); 604 605 /* 606 * If we successfully made the connection, load the host private key 607 * in case we will need it later for combined rsa-rhosts 608 * authentication. This must be done before releasing extra 609 * privileges, because the file is only readable by root. 610 * If we cannot access the private keys, load the public keys 611 * instead and try to execute the ssh-keysign helper instead. 612 */ 613 sensitive_data.nkeys = 0; 614 sensitive_data.keys = NULL; 615 sensitive_data.external_keysign = 0; 616 if (options.rhosts_rsa_authentication || 617 options.hostbased_authentication) { 618 sensitive_data.nkeys = 3; 619 sensitive_data.keys = xmalloc(sensitive_data.nkeys * 620 sizeof(Key)); 621 622 PRIV_START; 623 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 624 _PATH_HOST_KEY_FILE, "", NULL); 625 sensitive_data.keys[1] = key_load_private_type(KEY_DSA, 626 _PATH_HOST_DSA_KEY_FILE, "", NULL); 627 sensitive_data.keys[2] = key_load_private_type(KEY_RSA, 628 _PATH_HOST_RSA_KEY_FILE, "", NULL); 629 PRIV_END; 630 631 if (options.hostbased_authentication == 1 && 632 sensitive_data.keys[0] == NULL && 633 sensitive_data.keys[1] == NULL && 634 sensitive_data.keys[2] == NULL) { 635 sensitive_data.keys[1] = key_load_public( 636 _PATH_HOST_DSA_KEY_FILE, NULL); 637 sensitive_data.keys[2] = key_load_public( 638 _PATH_HOST_RSA_KEY_FILE, NULL); 639 sensitive_data.external_keysign = 1; 640 } 641 } 642 /* 643 * Get rid of any extra privileges that we may have. We will no 644 * longer need them. Also, extra privileges could make it very hard 645 * to read identity files and other non-world-readable files from the 646 * user's home directory if it happens to be on a NFS volume where 647 * root is mapped to nobody. 648 */ 649 seteuid(original_real_uid); 650 setuid(original_real_uid); 651 652 /* 653 * Now that we are back to our own permissions, create ~/.ssh 654 * directory if it doesn\'t already exist. 655 */ 656 snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 657 if (stat(buf, &st) < 0) 658 if (mkdir(buf, 0700) < 0) 659 error("Could not create directory '%.200s'.", buf); 660 661 /* load options.identity_files */ 662 load_public_identity_files(); 663 664 /* Expand ~ in known host file names. */ 665 /* XXX mem-leaks: */ 666 options.system_hostfile = 667 tilde_expand_filename(options.system_hostfile, original_real_uid); 668 options.user_hostfile = 669 tilde_expand_filename(options.user_hostfile, original_real_uid); 670 options.system_hostfile2 = 671 tilde_expand_filename(options.system_hostfile2, original_real_uid); 672 options.user_hostfile2 = 673 tilde_expand_filename(options.user_hostfile2, original_real_uid); 674 675 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 676 677 /* Log into the remote system. This never returns if the login fails. */ 678 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw); 679 680 /* We no longer need the private host keys. Clear them now. */ 681 if (sensitive_data.nkeys != 0) { 682 for (i = 0; i < sensitive_data.nkeys; i++) { 683 if (sensitive_data.keys[i] != NULL) { 684 /* Destroys contents safely */ 685 debug3("clear hostkey %d", i); 686 key_free(sensitive_data.keys[i]); 687 sensitive_data.keys[i] = NULL; 688 } 689 } 690 xfree(sensitive_data.keys); 691 } 692 for (i = 0; i < options.num_identity_files; i++) { 693 if (options.identity_files[i]) { 694 xfree(options.identity_files[i]); 695 options.identity_files[i] = NULL; 696 } 697 if (options.identity_keys[i]) { 698 key_free(options.identity_keys[i]); 699 options.identity_keys[i] = NULL; 700 } 701 } 702 703 exit_status = compat20 ? ssh_session2() : ssh_session(); 704 packet_close(); 705 706 /* 707 * Send SIGHUP to proxy command if used. We don't wait() in 708 * case it hangs and instead rely on init to reap the child 709 */ 710 if (proxy_command_pid > 1) 711 kill(proxy_command_pid, SIGHUP); 712 713 return exit_status; 714 } 715 716 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 717 718 static void 719 x11_get_proto(char **_proto, char **_data) 720 { 721 char cmd[1024]; 722 char line[512]; 723 char xdisplay[512]; 724 static char proto[512], data[512]; 725 FILE *f; 726 int got_data = 0, generated = 0, do_unlink = 0, i; 727 char *display, *xauthdir, *xauthfile; 728 struct stat st; 729 730 xauthdir = xauthfile = NULL; 731 *_proto = proto; 732 *_data = data; 733 proto[0] = data[0] = '\0'; 734 735 if (!options.xauth_location || 736 (stat(options.xauth_location, &st) == -1)) { 737 debug("No xauth program."); 738 } else { 739 if ((display = getenv("DISPLAY")) == NULL) { 740 debug("x11_get_proto: DISPLAY not set"); 741 return; 742 } 743 /* 744 * Handle FamilyLocal case where $DISPLAY does 745 * not match an authorization entry. For this we 746 * just try "xauth list unix:displaynum.screennum". 747 * XXX: "localhost" match to determine FamilyLocal 748 * is not perfect. 749 */ 750 if (strncmp(display, "localhost:", 10) == 0) { 751 snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 752 display + 10); 753 display = xdisplay; 754 } 755 if (options.forward_x11_trusted == 0) { 756 xauthdir = xmalloc(MAXPATHLEN); 757 xauthfile = xmalloc(MAXPATHLEN); 758 strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); 759 if (mkdtemp(xauthdir) != NULL) { 760 do_unlink = 1; 761 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile", 762 xauthdir); 763 snprintf(cmd, sizeof(cmd), 764 "%s -f %s generate %s " SSH_X11_PROTO 765 " untrusted timeout 120 2>" _PATH_DEVNULL, 766 options.xauth_location, xauthfile, display); 767 debug2("x11_get_proto: %s", cmd); 768 if (system(cmd) == 0) 769 generated = 1; 770 } 771 } 772 snprintf(cmd, sizeof(cmd), 773 "%s %s%s list %s . 2>" _PATH_DEVNULL, 774 options.xauth_location, 775 generated ? "-f " : "" , 776 generated ? xauthfile : "", 777 display); 778 debug2("x11_get_proto: %s", cmd); 779 f = popen(cmd, "r"); 780 if (f && fgets(line, sizeof(line), f) && 781 sscanf(line, "%*s %511s %511s", proto, data) == 2) 782 got_data = 1; 783 if (f) 784 pclose(f); 785 } 786 787 if (do_unlink) { 788 unlink(xauthfile); 789 rmdir(xauthdir); 790 } 791 if (xauthdir) 792 xfree(xauthdir); 793 if (xauthfile) 794 xfree(xauthfile); 795 796 /* 797 * If we didn't get authentication data, just make up some 798 * data. The forwarding code will check the validity of the 799 * response anyway, and substitute this data. The X11 800 * server, however, will ignore this fake data and use 801 * whatever authentication mechanisms it was using otherwise 802 * for the local connection. 803 */ 804 if (!got_data) { 805 u_int32_t rand = 0; 806 807 logit("Warning: No xauth data; " 808 "using fake authentication data for X11 forwarding."); 809 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 810 for (i = 0; i < 16; i++) { 811 if (i % 4 == 0) 812 rand = arc4random(); 813 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 814 rand & 0xff); 815 rand >>= 8; 816 } 817 } 818 } 819 820 static void 821 ssh_init_forwarding(void) 822 { 823 int success = 0; 824 int i; 825 826 /* Initiate local TCP/IP port forwardings. */ 827 for (i = 0; i < options.num_local_forwards; i++) { 828 debug("Connections to local port %d forwarded to remote address %.200s:%d", 829 options.local_forwards[i].port, 830 options.local_forwards[i].host, 831 options.local_forwards[i].host_port); 832 success += channel_setup_local_fwd_listener( 833 options.local_forwards[i].port, 834 options.local_forwards[i].host, 835 options.local_forwards[i].host_port, 836 options.gateway_ports); 837 } 838 if (i > 0 && success == 0) 839 error("Could not request local forwarding."); 840 841 /* Initiate remote TCP/IP port forwardings. */ 842 for (i = 0; i < options.num_remote_forwards; i++) { 843 debug("Connections to remote port %d forwarded to local address %.200s:%d", 844 options.remote_forwards[i].port, 845 options.remote_forwards[i].host, 846 options.remote_forwards[i].host_port); 847 channel_request_remote_forwarding( 848 options.remote_forwards[i].port, 849 options.remote_forwards[i].host, 850 options.remote_forwards[i].host_port); 851 } 852 } 853 854 static void 855 check_agent_present(void) 856 { 857 if (options.forward_agent) { 858 /* Clear agent forwarding if we don\'t have an agent. */ 859 if (!ssh_agent_present()) 860 options.forward_agent = 0; 861 } 862 } 863 864 static int 865 ssh_session(void) 866 { 867 int type; 868 int interactive = 0; 869 int have_tty = 0; 870 struct winsize ws; 871 char *cp; 872 873 /* Enable compression if requested. */ 874 if (options.compression) { 875 debug("Requesting compression at level %d.", options.compression_level); 876 877 if (options.compression_level < 1 || options.compression_level > 9) 878 fatal("Compression level must be from 1 (fast) to 9 (slow, best)."); 879 880 /* Send the request. */ 881 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 882 packet_put_int(options.compression_level); 883 packet_send(); 884 packet_write_wait(); 885 type = packet_read(); 886 if (type == SSH_SMSG_SUCCESS) 887 packet_start_compression(options.compression_level); 888 else if (type == SSH_SMSG_FAILURE) 889 logit("Warning: Remote host refused compression."); 890 else 891 packet_disconnect("Protocol error waiting for compression response."); 892 } 893 /* Allocate a pseudo tty if appropriate. */ 894 if (tty_flag) { 895 debug("Requesting pty."); 896 897 /* Start the packet. */ 898 packet_start(SSH_CMSG_REQUEST_PTY); 899 900 /* Store TERM in the packet. There is no limit on the 901 length of the string. */ 902 cp = getenv("TERM"); 903 if (!cp) 904 cp = ""; 905 packet_put_cstring(cp); 906 907 /* Store window size in the packet. */ 908 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 909 memset(&ws, 0, sizeof(ws)); 910 packet_put_int(ws.ws_row); 911 packet_put_int(ws.ws_col); 912 packet_put_int(ws.ws_xpixel); 913 packet_put_int(ws.ws_ypixel); 914 915 /* Store tty modes in the packet. */ 916 tty_make_modes(fileno(stdin), NULL); 917 918 /* Send the packet, and wait for it to leave. */ 919 packet_send(); 920 packet_write_wait(); 921 922 /* Read response from the server. */ 923 type = packet_read(); 924 if (type == SSH_SMSG_SUCCESS) { 925 interactive = 1; 926 have_tty = 1; 927 } else if (type == SSH_SMSG_FAILURE) 928 logit("Warning: Remote host failed or refused to allocate a pseudo tty."); 929 else 930 packet_disconnect("Protocol error waiting for pty request response."); 931 } 932 /* Request X11 forwarding if enabled and DISPLAY is set. */ 933 if (options.forward_x11 && getenv("DISPLAY") != NULL) { 934 char *proto, *data; 935 /* Get reasonable local authentication information. */ 936 x11_get_proto(&proto, &data); 937 /* Request forwarding with authentication spoofing. */ 938 debug("Requesting X11 forwarding with authentication spoofing."); 939 x11_request_forwarding_with_spoofing(0, proto, data); 940 941 /* Read response from the server. */ 942 type = packet_read(); 943 if (type == SSH_SMSG_SUCCESS) { 944 interactive = 1; 945 } else if (type == SSH_SMSG_FAILURE) { 946 logit("Warning: Remote host denied X11 forwarding."); 947 } else { 948 packet_disconnect("Protocol error waiting for X11 forwarding"); 949 } 950 } 951 /* Tell the packet module whether this is an interactive session. */ 952 packet_set_interactive(interactive); 953 954 /* Request authentication agent forwarding if appropriate. */ 955 check_agent_present(); 956 957 if (options.forward_agent) { 958 debug("Requesting authentication agent forwarding."); 959 auth_request_forwarding(); 960 961 /* Read response from the server. */ 962 type = packet_read(); 963 packet_check_eom(); 964 if (type != SSH_SMSG_SUCCESS) 965 logit("Warning: Remote host denied authentication agent forwarding."); 966 } 967 968 /* Initiate port forwardings. */ 969 ssh_init_forwarding(); 970 971 /* If requested, let ssh continue in the background. */ 972 if (fork_after_authentication_flag) 973 if (daemon(1, 1) < 0) 974 fatal("daemon() failed: %.200s", strerror(errno)); 975 976 /* 977 * If a command was specified on the command line, execute the 978 * command now. Otherwise request the server to start a shell. 979 */ 980 if (buffer_len(&command) > 0) { 981 int len = buffer_len(&command); 982 if (len > 900) 983 len = 900; 984 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command)); 985 packet_start(SSH_CMSG_EXEC_CMD); 986 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 987 packet_send(); 988 packet_write_wait(); 989 } else { 990 debug("Requesting shell."); 991 packet_start(SSH_CMSG_EXEC_SHELL); 992 packet_send(); 993 packet_write_wait(); 994 } 995 996 /* Enter the interactive session. */ 997 return client_loop(have_tty, tty_flag ? 998 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 999 } 1000 1001 static void 1002 client_subsystem_reply(int type, u_int32_t seq, void *ctxt) 1003 { 1004 int id, len; 1005 1006 id = packet_get_int(); 1007 len = buffer_len(&command); 1008 if (len > 900) 1009 len = 900; 1010 packet_check_eom(); 1011 if (type == SSH2_MSG_CHANNEL_FAILURE) 1012 fatal("Request for subsystem '%.*s' failed on channel %d", 1013 len, (u_char *)buffer_ptr(&command), id); 1014 } 1015 1016 void 1017 client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt) 1018 { 1019 int i; 1020 1021 i = client_global_request_id++; 1022 if (i >= options.num_remote_forwards) 1023 return; 1024 debug("remote forward %s for: listen %d, connect %s:%d", 1025 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 1026 options.remote_forwards[i].port, 1027 options.remote_forwards[i].host, 1028 options.remote_forwards[i].host_port); 1029 if (type == SSH2_MSG_REQUEST_FAILURE) 1030 logit("Warning: remote port forwarding failed for listen port %d", 1031 options.remote_forwards[i].port); 1032 } 1033 1034 /* request pty/x11/agent/tcpfwd/shell for channel */ 1035 static void 1036 ssh_session2_setup(int id, void *arg) 1037 { 1038 int len; 1039 int interactive = 0; 1040 struct termios tio; 1041 1042 debug2("ssh_session2_setup: id %d", id); 1043 1044 if (tty_flag) { 1045 struct winsize ws; 1046 char *cp; 1047 cp = getenv("TERM"); 1048 if (!cp) 1049 cp = ""; 1050 /* Store window size in the packet. */ 1051 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1052 memset(&ws, 0, sizeof(ws)); 1053 1054 channel_request_start(id, "pty-req", 0); 1055 packet_put_cstring(cp); 1056 packet_put_int(ws.ws_col); 1057 packet_put_int(ws.ws_row); 1058 packet_put_int(ws.ws_xpixel); 1059 packet_put_int(ws.ws_ypixel); 1060 tio = get_saved_tio(); 1061 tty_make_modes(/*ignored*/ 0, &tio); 1062 packet_send(); 1063 interactive = 1; 1064 /* XXX wait for reply */ 1065 } 1066 if (options.forward_x11 && 1067 getenv("DISPLAY") != NULL) { 1068 char *proto, *data; 1069 /* Get reasonable local authentication information. */ 1070 x11_get_proto(&proto, &data); 1071 /* Request forwarding with authentication spoofing. */ 1072 debug("Requesting X11 forwarding with authentication spoofing."); 1073 x11_request_forwarding_with_spoofing(id, proto, data); 1074 interactive = 1; 1075 /* XXX wait for reply */ 1076 } 1077 1078 check_agent_present(); 1079 if (options.forward_agent) { 1080 debug("Requesting authentication agent forwarding."); 1081 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1082 packet_send(); 1083 } 1084 1085 len = buffer_len(&command); 1086 if (len > 0) { 1087 if (len > 900) 1088 len = 900; 1089 if (subsystem_flag) { 1090 debug("Sending subsystem: %.*s", len, (u_char *)buffer_ptr(&command)); 1091 channel_request_start(id, "subsystem", /*want reply*/ 1); 1092 /* register callback for reply */ 1093 /* XXX we assume that client_loop has already been called */ 1094 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply); 1095 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply); 1096 } else { 1097 debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command)); 1098 channel_request_start(id, "exec", 0); 1099 } 1100 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1101 packet_send(); 1102 } else { 1103 channel_request_start(id, "shell", 0); 1104 packet_send(); 1105 } 1106 1107 packet_set_interactive(interactive); 1108 } 1109 1110 /* open new channel for a session */ 1111 static int 1112 ssh_session2_open(void) 1113 { 1114 Channel *c; 1115 int window, packetmax, in, out, err; 1116 1117 if (stdin_null_flag) { 1118 in = open(_PATH_DEVNULL, O_RDONLY); 1119 } else { 1120 in = dup(STDIN_FILENO); 1121 } 1122 out = dup(STDOUT_FILENO); 1123 err = dup(STDERR_FILENO); 1124 1125 if (in < 0 || out < 0 || err < 0) 1126 fatal("dup() in/out/err failed"); 1127 1128 /* enable nonblocking unless tty */ 1129 if (!isatty(in)) 1130 set_nonblock(in); 1131 if (!isatty(out)) 1132 set_nonblock(out); 1133 if (!isatty(err)) 1134 set_nonblock(err); 1135 1136 window = CHAN_SES_WINDOW_DEFAULT; 1137 packetmax = CHAN_SES_PACKET_DEFAULT; 1138 if (tty_flag) { 1139 window >>= 1; 1140 packetmax >>= 1; 1141 } 1142 c = channel_new( 1143 "session", SSH_CHANNEL_OPENING, in, out, err, 1144 window, packetmax, CHAN_EXTENDED_WRITE, 1145 "client-session", /*nonblock*/0); 1146 1147 debug3("ssh_session2_open: channel_new: %d", c->self); 1148 1149 channel_send_open(c->self); 1150 if (!no_shell_flag) 1151 channel_register_confirm(c->self, ssh_session2_setup); 1152 1153 return c->self; 1154 } 1155 1156 static int 1157 ssh_session2(void) 1158 { 1159 int id = -1; 1160 1161 /* XXX should be pre-session */ 1162 ssh_init_forwarding(); 1163 1164 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1165 id = ssh_session2_open(); 1166 1167 /* If requested, let ssh continue in the background. */ 1168 if (fork_after_authentication_flag) 1169 if (daemon(1, 1) < 0) 1170 fatal("daemon() failed: %.200s", strerror(errno)); 1171 1172 return client_loop(tty_flag, tty_flag ? 1173 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1174 } 1175 1176 static void 1177 load_public_identity_files(void) 1178 { 1179 char *filename; 1180 int i = 0; 1181 Key *public; 1182 #ifdef SMARTCARD 1183 Key **keys; 1184 1185 if (options.smartcard_device != NULL && 1186 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1187 (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL ) { 1188 int count = 0; 1189 for (i = 0; keys[i] != NULL; i++) { 1190 count++; 1191 memmove(&options.identity_files[1], &options.identity_files[0], 1192 sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1)); 1193 memmove(&options.identity_keys[1], &options.identity_keys[0], 1194 sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1)); 1195 options.num_identity_files++; 1196 options.identity_keys[0] = keys[i]; 1197 options.identity_files[0] = sc_get_key_label(keys[i]); 1198 } 1199 if (options.num_identity_files > SSH_MAX_IDENTITY_FILES) 1200 options.num_identity_files = SSH_MAX_IDENTITY_FILES; 1201 i = count; 1202 xfree(keys); 1203 } 1204 #endif /* SMARTCARD */ 1205 for (; i < options.num_identity_files; i++) { 1206 filename = tilde_expand_filename(options.identity_files[i], 1207 original_real_uid); 1208 public = key_load_public(filename, NULL); 1209 debug("identity file %s type %d", filename, 1210 public ? public->type : -1); 1211 xfree(options.identity_files[i]); 1212 options.identity_files[i] = filename; 1213 options.identity_keys[i] = public; 1214 } 1215 } 1216