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 * 17 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu> 18 * in Canada (German citizen). 19 * 20 * Redistribution and use in source and binary forms, with or without 21 * modification, are permitted provided that the following conditions 22 * are met: 23 * 1. Redistributions of source code must retain the above copyright 24 * notice, this list of conditions and the following disclaimer. 25 * 2. Redistributions in binary form must reproduce the above copyright 26 * notice, this list of conditions and the following disclaimer in the 27 * documentation and/or other materials provided with the distribution. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 */ 40 41 #include "includes.h" 42 RCSID("$OpenBSD: ssh.c,v 1.138 2001/08/11 22:51:27 jakob Exp $"); 43 44 #include <openssl/evp.h> 45 #include <openssl/err.h> 46 47 #include "ssh.h" 48 #include "ssh1.h" 49 #include "ssh2.h" 50 #include "compat.h" 51 #include "cipher.h" 52 #include "xmalloc.h" 53 #include "packet.h" 54 #include "buffer.h" 55 #include "uidswap.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 <openssl/engine.h> 74 #include "scard.h" 75 #endif 76 77 extern char *__progname; 78 79 /* Flag indicating whether IPv4 or IPv6. This can be set on the command line. 80 Default value is AF_UNSPEC means both IPv4 and IPv6. */ 81 int IPv4or6 = AF_UNSPEC; 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 pasphrase 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 /* 114 * Name of the host we are connecting to. This is the name given on the 115 * command line, or the HostName specified for the user-supplied name in a 116 * configuration file. 117 */ 118 char *host; 119 120 /* socket address the host resolves to */ 121 struct sockaddr_storage hostaddr; 122 123 /* 124 * Flag to indicate that we have received a window change signal which has 125 * not yet been processed. This will cause a message indicating the new 126 * window size to be sent to the server a little later. This is volatile 127 * because this is updated in a signal handler. 128 */ 129 volatile int received_window_change_signal = 0; 130 131 /* Private host keys. */ 132 struct { 133 Key **keys; 134 int nkeys; 135 } sensitive_data; 136 137 /* Original real UID. */ 138 uid_t original_real_uid; 139 140 /* command to be executed */ 141 Buffer command; 142 143 /* Should we execute a command or invoke a subsystem? */ 144 int subsystem_flag = 0; 145 146 /* Prints a help message to the user. This function never returns. */ 147 148 static void 149 usage(void) 150 { 151 fprintf(stderr, "Usage: %s [options] host [command]\n", __progname); 152 fprintf(stderr, "Options:\n"); 153 fprintf(stderr, " -l user Log in using this user name.\n"); 154 fprintf(stderr, " -n Redirect input from " _PATH_DEVNULL ".\n"); 155 fprintf(stderr, " -A Enable authentication agent forwarding.\n"); 156 fprintf(stderr, " -a Disable authentication agent forwarding (default).\n"); 157 #ifdef AFS 158 fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n"); 159 #endif /* AFS */ 160 fprintf(stderr, " -X Enable X11 connection forwarding.\n"); 161 fprintf(stderr, " -x Disable X11 connection forwarding (default).\n"); 162 fprintf(stderr, " -i file Identity for public key authentication " 163 "(default: ~/.ssh/identity)\n"); 164 #ifdef SMARTCARD 165 fprintf(stderr, " -I reader Set smartcard reader.\n"); 166 #endif 167 fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n"); 168 fprintf(stderr, " -T Do not allocate a tty.\n"); 169 fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); 170 fprintf(stderr, " Multiple -v increases verbosity.\n"); 171 fprintf(stderr, " -V Display version number only.\n"); 172 fprintf(stderr, " -P Don't allocate a privileged port.\n"); 173 fprintf(stderr, " -q Quiet; don't display any warning messages.\n"); 174 fprintf(stderr, " -f Fork into background after authentication.\n"); 175 fprintf(stderr, " -e char Set escape character; ``none'' = disable (default: ~).\n"); 176 177 fprintf(stderr, " -c cipher Select encryption algorithm\n"); 178 fprintf(stderr, " -m macs Specify MAC algorithms for protocol version 2.\n"); 179 fprintf(stderr, " -p port Connect to this port. Server must be on the same port.\n"); 180 fprintf(stderr, " -L listen-port:host:port Forward local port to remote address\n"); 181 fprintf(stderr, " -R listen-port:host:port Forward remote port to local address\n"); 182 fprintf(stderr, " These cause %s to listen for connections on a port, and\n", __progname); 183 fprintf(stderr, " forward them to the other side by connecting to host:port.\n"); 184 fprintf(stderr, " -C Enable compression.\n"); 185 fprintf(stderr, " -N Do not execute a shell or command.\n"); 186 fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n"); 187 fprintf(stderr, " -1 Force protocol version 1.\n"); 188 fprintf(stderr, " -2 Force protocol version 2.\n"); 189 fprintf(stderr, " -4 Use IPv4 only.\n"); 190 fprintf(stderr, " -6 Use IPv6 only.\n"); 191 fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n"); 192 fprintf(stderr, " -s Invoke command (mandatory) as SSH2 subsystem.\n"); 193 fprintf(stderr, " -b addr Local IP address.\n"); 194 exit(1); 195 } 196 197 /* 198 * Connects to the given host using rsh (or prints an error message and exits 199 * if rsh is not available). This function never returns. 200 */ 201 static void 202 rsh_connect(char *host, char *user, Buffer * command) 203 { 204 char *args[10]; 205 int i; 206 207 log("Using rsh. WARNING: Connection will not be encrypted."); 208 /* Build argument list for rsh. */ 209 i = 0; 210 args[i++] = _PATH_RSH; 211 /* host may have to come after user on some systems */ 212 args[i++] = host; 213 if (user) { 214 args[i++] = "-l"; 215 args[i++] = user; 216 } 217 if (buffer_len(command) > 0) { 218 buffer_append(command, "\0", 1); 219 args[i++] = buffer_ptr(command); 220 } 221 args[i++] = NULL; 222 if (debug_flag) { 223 for (i = 0; args[i]; i++) { 224 if (i != 0) 225 fprintf(stderr, " "); 226 fprintf(stderr, "%s", args[i]); 227 } 228 fprintf(stderr, "\n"); 229 } 230 execv(_PATH_RSH, args); 231 perror(_PATH_RSH); 232 exit(1); 233 } 234 235 static int ssh_session(void); 236 static int ssh_session2(void); 237 static void load_public_identity_files(void); 238 239 /* 240 * Main program for the ssh client. 241 */ 242 int 243 main(int ac, char **av) 244 { 245 int i, opt, exit_status, cerr; 246 u_short fwd_port, fwd_host_port; 247 char *p, *cp, buf[256]; 248 struct stat st; 249 struct passwd *pw; 250 int dummy; 251 uid_t original_effective_uid; 252 253 /* 254 * Save the original real uid. It will be needed later (uid-swapping 255 * may clobber the real uid). 256 */ 257 original_real_uid = getuid(); 258 original_effective_uid = geteuid(); 259 260 /* If we are installed setuid root be careful to not drop core. */ 261 if (original_real_uid != original_effective_uid) { 262 struct rlimit rlim; 263 rlim.rlim_cur = rlim.rlim_max = 0; 264 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 265 fatal("setrlimit failed: %.100s", strerror(errno)); 266 } 267 /* Get user data. */ 268 pw = getpwuid(original_real_uid); 269 if (!pw) { 270 log("You don't exist, go away!"); 271 exit(1); 272 } 273 /* Take a copy of the returned structure. */ 274 pw = pwcopy(pw); 275 276 /* 277 * Use uid-swapping to give up root privileges for the duration of 278 * option processing. We will re-instantiate the rights when we are 279 * ready to create the privileged port, and will permanently drop 280 * them when the port has been created (actually, when the connection 281 * has been made, as we may need to create the port several times). 282 */ 283 temporarily_use_uid(pw); 284 285 /* 286 * Set our umask to something reasonable, as some files are created 287 * with the default umask. This will make them world-readable but 288 * writable only by the owner, which is ok for all files for which we 289 * don't set the modes explicitly. 290 */ 291 umask(022); 292 293 /* Initialize option structure to indicate that no values have been set. */ 294 initialize_options(&options); 295 296 /* Parse command-line arguments. */ 297 host = NULL; 298 299 again: 300 while ((opt = getopt(ac, av, 301 "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:I:L:NPR:TVX")) != -1) { 302 switch (opt) { 303 case '1': 304 options.protocol = SSH_PROTO_1; 305 break; 306 case '2': 307 options.protocol = SSH_PROTO_2; 308 break; 309 case '4': 310 IPv4or6 = AF_INET; 311 break; 312 case '6': 313 IPv4or6 = AF_INET6; 314 break; 315 case 'n': 316 stdin_null_flag = 1; 317 break; 318 case 'f': 319 fork_after_authentication_flag = 1; 320 stdin_null_flag = 1; 321 break; 322 case 'x': 323 options.forward_x11 = 0; 324 break; 325 case 'X': 326 options.forward_x11 = 1; 327 break; 328 case 'g': 329 options.gateway_ports = 1; 330 break; 331 case 'P': 332 options.use_privileged_port = 0; 333 break; 334 case 'a': 335 options.forward_agent = 0; 336 break; 337 case 'A': 338 options.forward_agent = 1; 339 break; 340 #ifdef AFS 341 case 'k': 342 options.kerberos_tgt_passing = 0; 343 options.afs_token_passing = 0; 344 break; 345 #endif 346 case 'i': 347 if (stat(optarg, &st) < 0) { 348 fprintf(stderr, "Warning: Identity file %s " 349 "does not exist.\n", optarg); 350 break; 351 } 352 if (options.num_identity_files >= 353 SSH_MAX_IDENTITY_FILES) 354 fatal("Too many identity files specified " 355 "(max %d)", SSH_MAX_IDENTITY_FILES); 356 options.identity_files[options.num_identity_files++] = 357 xstrdup(optarg); 358 break; 359 case 'I': 360 #ifdef SMARTCARD 361 options.smartcard_device = xstrdup(optarg); 362 #else 363 fprintf(stderr, "no support for smartcards.\n"); 364 #endif 365 break; 366 case 't': 367 if (tty_flag) 368 force_tty_flag = 1; 369 tty_flag = 1; 370 break; 371 case 'v': 372 if (0 == debug_flag) { 373 debug_flag = 1; 374 options.log_level = SYSLOG_LEVEL_DEBUG1; 375 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) { 376 options.log_level++; 377 break; 378 } else 379 fatal("Too high debugging level."); 380 /* fallthrough */ 381 case 'V': 382 fprintf(stderr, 383 "%s, SSH protocols %d.%d/%d.%d, OpenSSL 0x%8.8lx\n", 384 SSH_VERSION, 385 PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1, 386 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, 387 SSLeay()); 388 if (opt == 'V') 389 exit(0); 390 break; 391 case 'q': 392 options.log_level = SYSLOG_LEVEL_QUIET; 393 break; 394 case 'e': 395 if (optarg[0] == '^' && optarg[2] == 0 && 396 (u_char) optarg[1] >= 64 && 397 (u_char) optarg[1] < 128) 398 options.escape_char = (u_char) optarg[1] & 31; 399 else if (strlen(optarg) == 1) 400 options.escape_char = (u_char) optarg[0]; 401 else if (strcmp(optarg, "none") == 0) 402 options.escape_char = SSH_ESCAPECHAR_NONE; 403 else { 404 fprintf(stderr, "Bad escape character '%s'.\n", 405 optarg); 406 exit(1); 407 } 408 break; 409 case 'c': 410 if (ciphers_valid(optarg)) { 411 /* SSH2 only */ 412 options.ciphers = xstrdup(optarg); 413 options.cipher = SSH_CIPHER_ILLEGAL; 414 } else { 415 /* SSH1 only */ 416 options.cipher = cipher_number(optarg); 417 if (options.cipher == -1) { 418 fprintf(stderr, 419 "Unknown cipher type '%s'\n", 420 optarg); 421 exit(1); 422 } 423 if (options.cipher == SSH_CIPHER_3DES) 424 options.ciphers = "3des-cbc"; 425 else if (options.cipher == SSH_CIPHER_BLOWFISH) 426 options.ciphers = "blowfish-cbc"; 427 else 428 options.ciphers = (char *)-1; 429 } 430 break; 431 case 'm': 432 if (mac_valid(optarg)) 433 options.macs = xstrdup(optarg); 434 else { 435 fprintf(stderr, "Unknown mac type '%s'\n", 436 optarg); 437 exit(1); 438 } 439 break; 440 case 'p': 441 options.port = a2port(optarg); 442 if (options.port == 0) { 443 fprintf(stderr, "Bad port '%s'\n", optarg); 444 exit(1); 445 } 446 break; 447 case 'l': 448 options.user = optarg; 449 break; 450 case 'R': 451 if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf, 452 &fwd_host_port) != 3 && 453 sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf, 454 &fwd_host_port) != 3) { 455 fprintf(stderr, 456 "Bad forwarding specification '%s'.\n", 457 optarg); 458 usage(); 459 /* NOTREACHED */ 460 } 461 add_remote_forward(&options, fwd_port, buf, 462 fwd_host_port); 463 break; 464 case 'L': 465 if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf, 466 &fwd_host_port) != 3 && 467 sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf, 468 &fwd_host_port) != 3) { 469 fprintf(stderr, 470 "Bad forwarding specification '%s'.\n", 471 optarg); 472 usage(); 473 /* NOTREACHED */ 474 } 475 add_local_forward(&options, fwd_port, buf, 476 fwd_host_port); 477 break; 478 479 case 'D': 480 fwd_port = a2port(optarg); 481 if (fwd_port == 0) { 482 fprintf(stderr, "Bad dynamic port '%s'\n", 483 optarg); 484 exit(1); 485 } 486 add_local_forward(&options, fwd_port, "socks4", 0); 487 break; 488 489 case 'C': 490 options.compression = 1; 491 break; 492 case 'N': 493 no_shell_flag = 1; 494 no_tty_flag = 1; 495 break; 496 case 'T': 497 no_tty_flag = 1; 498 break; 499 case 'o': 500 dummy = 1; 501 if (process_config_line(&options, host ? host : "", 502 optarg, "command-line", 0, &dummy) != 0) 503 exit(1); 504 break; 505 case 's': 506 subsystem_flag = 1; 507 break; 508 case 'b': 509 options.bind_address = optarg; 510 break; 511 default: 512 usage(); 513 } 514 } 515 516 ac -= optind; 517 av += optind; 518 519 if (ac > 0 && !host && **av != '-') { 520 if (strchr(*av, '@')) { 521 p = xstrdup(*av); 522 cp = strchr(p, '@'); 523 if (cp == NULL || cp == p) 524 usage(); 525 options.user = p; 526 *cp = '\0'; 527 host = ++cp; 528 } else 529 host = *av; 530 ac--, av++; 531 if (ac > 0) { 532 optind = 0; 533 optreset = 1; 534 goto again; 535 } 536 } 537 538 /* Check that we got a host name. */ 539 if (!host) 540 usage(); 541 542 SSLeay_add_all_algorithms(); 543 ERR_load_crypto_strings(); 544 545 /* Initialize the command to execute on remote host. */ 546 buffer_init(&command); 547 548 /* 549 * Save the command to execute on the remote host in a buffer. There 550 * is no limit on the length of the command, except by the maximum 551 * packet size. Also sets the tty flag if there is no command. 552 */ 553 if (!ac) { 554 /* No command specified - execute shell on a tty. */ 555 tty_flag = 1; 556 if (subsystem_flag) { 557 fprintf(stderr, 558 "You must specify a subsystem to invoke.\n"); 559 usage(); 560 } 561 } else { 562 /* A command has been specified. Store it into the buffer. */ 563 for (i = 0; i < ac; i++) { 564 if (i) 565 buffer_append(&command, " ", 1); 566 buffer_append(&command, av[i], strlen(av[i])); 567 } 568 } 569 570 /* Cannot fork to background if no command. */ 571 if (fork_after_authentication_flag && buffer_len(&command) == 0 && !no_shell_flag) 572 fatal("Cannot fork into background without a command to execute."); 573 574 /* Allocate a tty by default if no command specified. */ 575 if (buffer_len(&command) == 0) 576 tty_flag = 1; 577 578 /* Force no tty*/ 579 if (no_tty_flag) 580 tty_flag = 0; 581 /* Do not allocate a tty if stdin is not a tty. */ 582 if (!isatty(fileno(stdin)) && !force_tty_flag) { 583 if (tty_flag) 584 log("Pseudo-terminal will not be allocated because stdin is not a terminal."); 585 tty_flag = 0; 586 } 587 588 /* 589 * Initialize "log" output. Since we are the client all output 590 * actually goes to stderr. 591 */ 592 log_init(av[0], options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 593 SYSLOG_FACILITY_USER, 1); 594 595 /* Read per-user configuration file. */ 596 snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE); 597 read_config_file(buf, host, &options); 598 599 /* Read systemwide configuration file. */ 600 read_config_file(_PATH_HOST_CONFIG_FILE, host, &options); 601 602 /* Fill configuration defaults. */ 603 fill_default_options(&options); 604 605 /* reinit */ 606 log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 1); 607 608 if (options.user == NULL) 609 options.user = xstrdup(pw->pw_name); 610 611 if (options.hostname != NULL) 612 host = options.hostname; 613 614 /* Disable rhosts authentication if not running as root. */ 615 if (original_effective_uid != 0 || !options.use_privileged_port) { 616 debug("Rhosts Authentication disabled, " 617 "originating port will not be trusted."); 618 options.rhosts_authentication = 0; 619 } 620 /* 621 * If using rsh has been selected, exec it now (without trying 622 * anything else). Note that we must release privileges first. 623 */ 624 if (options.use_rsh) { 625 /* 626 * Restore our superuser privileges. This must be done 627 * before permanently setting the uid. 628 */ 629 restore_uid(); 630 631 /* Switch to the original uid permanently. */ 632 permanently_set_uid(pw); 633 634 /* Execute rsh. */ 635 rsh_connect(host, options.user, &command); 636 fatal("rsh_connect returned"); 637 } 638 /* Restore our superuser privileges. */ 639 restore_uid(); 640 641 /* Open a connection to the remote host. */ 642 643 cerr = ssh_connect(host, &hostaddr, options.port, 644 options.connection_attempts, 645 original_effective_uid != 0 || !options.use_privileged_port, 646 pw, options.proxy_command); 647 648 /* 649 * If we successfully made the connection, load the host private key 650 * in case we will need it later for combined rsa-rhosts 651 * authentication. This must be done before releasing extra 652 * privileges, because the file is only readable by root. 653 */ 654 sensitive_data.nkeys = 0; 655 sensitive_data.keys = NULL; 656 if (!cerr && (options.rhosts_rsa_authentication || 657 options.hostbased_authentication)) { 658 sensitive_data.nkeys = 3; 659 sensitive_data.keys = xmalloc(sensitive_data.nkeys*sizeof(Key)); 660 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 661 _PATH_HOST_KEY_FILE, "", NULL); 662 sensitive_data.keys[1] = key_load_private_type(KEY_DSA, 663 _PATH_HOST_DSA_KEY_FILE, "", NULL); 664 sensitive_data.keys[2] = key_load_private_type(KEY_RSA, 665 _PATH_HOST_RSA_KEY_FILE, "", NULL); 666 } 667 /* 668 * Get rid of any extra privileges that we may have. We will no 669 * longer need them. Also, extra privileges could make it very hard 670 * to read identity files and other non-world-readable files from the 671 * user's home directory if it happens to be on a NFS volume where 672 * root is mapped to nobody. 673 */ 674 675 /* 676 * Note that some legacy systems need to postpone the following call 677 * to permanently_set_uid() until the private hostkey is destroyed 678 * with RSA_free(). Otherwise the calling user could ptrace() the 679 * process, read the private hostkey and impersonate the host. 680 * OpenBSD does not allow ptracing of setuid processes. 681 */ 682 permanently_set_uid(pw); 683 684 /* 685 * Now that we are back to our own permissions, create ~/.ssh 686 * directory if it doesn\'t already exist. 687 */ 688 snprintf(buf, sizeof buf, "%.100s%s%.100s", pw->pw_dir, strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 689 if (stat(buf, &st) < 0) 690 if (mkdir(buf, 0700) < 0) 691 error("Could not create directory '%.200s'.", buf); 692 693 /* Check if the connection failed, and try "rsh" if appropriate. */ 694 if (cerr) { 695 if (!options.fallback_to_rsh) 696 exit(1); 697 if (options.port != 0) 698 log("Secure connection to %.100s on port %hu refused; " 699 "reverting to insecure method", 700 host, options.port); 701 else 702 log("Secure connection to %.100s refused; " 703 "reverting to insecure method.", host); 704 705 rsh_connect(host, options.user, &command); 706 fatal("rsh_connect returned"); 707 } 708 /* load options.identity_files */ 709 load_public_identity_files(); 710 711 /* Expand ~ in known host file names. */ 712 /* XXX mem-leaks: */ 713 options.system_hostfile = 714 tilde_expand_filename(options.system_hostfile, original_real_uid); 715 options.user_hostfile = 716 tilde_expand_filename(options.user_hostfile, original_real_uid); 717 options.system_hostfile2 = 718 tilde_expand_filename(options.system_hostfile2, original_real_uid); 719 options.user_hostfile2 = 720 tilde_expand_filename(options.user_hostfile2, original_real_uid); 721 722 /* Log into the remote system. This never returns if the login fails. */ 723 ssh_login(sensitive_data.keys, sensitive_data.nkeys, 724 host, (struct sockaddr *)&hostaddr, pw); 725 726 /* We no longer need the private host keys. Clear them now. */ 727 if (sensitive_data.nkeys != 0) { 728 for (i = 0; i < sensitive_data.nkeys; i++) { 729 if (sensitive_data.keys[i] != NULL) { 730 /* Destroys contents safely */ 731 debug3("clear hostkey %d", i); 732 key_free(sensitive_data.keys[i]); 733 sensitive_data.keys[i] = NULL; 734 } 735 } 736 xfree(sensitive_data.keys); 737 } 738 for (i = 0; i < options.num_identity_files; i++) { 739 if (options.identity_files[i]) { 740 xfree(options.identity_files[i]); 741 options.identity_files[i] = NULL; 742 } 743 if (options.identity_keys[i]) { 744 key_free(options.identity_keys[i]); 745 options.identity_keys[i] = NULL; 746 } 747 } 748 749 exit_status = compat20 ? ssh_session2() : ssh_session(); 750 packet_close(); 751 return exit_status; 752 } 753 754 static void 755 x11_get_proto(char *proto, int proto_len, char *data, int data_len) 756 { 757 char line[512]; 758 FILE *f; 759 int got_data = 0, i; 760 761 if (options.xauth_location) { 762 /* Try to get Xauthority information for the display. */ 763 snprintf(line, sizeof line, "%.100s list %.200s 2>" _PATH_DEVNULL, 764 options.xauth_location, getenv("DISPLAY")); 765 f = popen(line, "r"); 766 if (f && fgets(line, sizeof(line), f) && 767 sscanf(line, "%*s %s %s", proto, data) == 2) 768 got_data = 1; 769 if (f) 770 pclose(f); 771 } 772 /* 773 * If we didn't get authentication data, just make up some 774 * data. The forwarding code will check the validity of the 775 * response anyway, and substitute this data. The X11 776 * server, however, will ignore this fake data and use 777 * whatever authentication mechanisms it was using otherwise 778 * for the local connection. 779 */ 780 if (!got_data) { 781 u_int32_t rand = 0; 782 783 strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len); 784 for (i = 0; i < 16; i++) { 785 if (i % 4 == 0) 786 rand = arc4random(); 787 snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff); 788 rand >>= 8; 789 } 790 } 791 } 792 793 static void 794 ssh_init_forwarding(void) 795 { 796 int success = 0; 797 int i; 798 799 /* Initiate local TCP/IP port forwardings. */ 800 for (i = 0; i < options.num_local_forwards; i++) { 801 debug("Connections to local port %d forwarded to remote address %.200s:%d", 802 options.local_forwards[i].port, 803 options.local_forwards[i].host, 804 options.local_forwards[i].host_port); 805 success += channel_request_local_forwarding( 806 options.local_forwards[i].port, 807 options.local_forwards[i].host, 808 options.local_forwards[i].host_port, 809 options.gateway_ports); 810 } 811 if (i > 0 && success == 0) 812 error("Could not request local forwarding."); 813 814 /* Initiate remote TCP/IP port forwardings. */ 815 for (i = 0; i < options.num_remote_forwards; i++) { 816 debug("Connections to remote port %d forwarded to local address %.200s:%d", 817 options.remote_forwards[i].port, 818 options.remote_forwards[i].host, 819 options.remote_forwards[i].host_port); 820 channel_request_remote_forwarding( 821 options.remote_forwards[i].port, 822 options.remote_forwards[i].host, 823 options.remote_forwards[i].host_port); 824 } 825 } 826 827 static void 828 check_agent_present(void) 829 { 830 if (options.forward_agent) { 831 /* Clear agent forwarding if we don\'t have an agent. */ 832 int authfd = ssh_get_authentication_socket(); 833 if (authfd < 0) 834 options.forward_agent = 0; 835 else 836 ssh_close_authentication_socket(authfd); 837 } 838 } 839 840 static int 841 ssh_session(void) 842 { 843 int type; 844 int plen; 845 int interactive = 0; 846 int have_tty = 0; 847 struct winsize ws; 848 char *cp; 849 850 /* Enable compression if requested. */ 851 if (options.compression) { 852 debug("Requesting compression at level %d.", options.compression_level); 853 854 if (options.compression_level < 1 || options.compression_level > 9) 855 fatal("Compression level must be from 1 (fast) to 9 (slow, best)."); 856 857 /* Send the request. */ 858 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 859 packet_put_int(options.compression_level); 860 packet_send(); 861 packet_write_wait(); 862 type = packet_read(&plen); 863 if (type == SSH_SMSG_SUCCESS) 864 packet_start_compression(options.compression_level); 865 else if (type == SSH_SMSG_FAILURE) 866 log("Warning: Remote host refused compression."); 867 else 868 packet_disconnect("Protocol error waiting for compression response."); 869 } 870 /* Allocate a pseudo tty if appropriate. */ 871 if (tty_flag) { 872 debug("Requesting pty."); 873 874 /* Start the packet. */ 875 packet_start(SSH_CMSG_REQUEST_PTY); 876 877 /* Store TERM in the packet. There is no limit on the 878 length of the string. */ 879 cp = getenv("TERM"); 880 if (!cp) 881 cp = ""; 882 packet_put_cstring(cp); 883 884 /* Store window size in the packet. */ 885 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 886 memset(&ws, 0, sizeof(ws)); 887 packet_put_int(ws.ws_row); 888 packet_put_int(ws.ws_col); 889 packet_put_int(ws.ws_xpixel); 890 packet_put_int(ws.ws_ypixel); 891 892 /* Store tty modes in the packet. */ 893 tty_make_modes(fileno(stdin), NULL); 894 895 /* Send the packet, and wait for it to leave. */ 896 packet_send(); 897 packet_write_wait(); 898 899 /* Read response from the server. */ 900 type = packet_read(&plen); 901 if (type == SSH_SMSG_SUCCESS) { 902 interactive = 1; 903 have_tty = 1; 904 } else if (type == SSH_SMSG_FAILURE) 905 log("Warning: Remote host failed or refused to allocate a pseudo tty."); 906 else 907 packet_disconnect("Protocol error waiting for pty request response."); 908 } 909 /* Request X11 forwarding if enabled and DISPLAY is set. */ 910 if (options.forward_x11 && getenv("DISPLAY") != NULL) { 911 char proto[512], data[512]; 912 /* Get reasonable local authentication information. */ 913 x11_get_proto(proto, sizeof proto, data, sizeof data); 914 /* Request forwarding with authentication spoofing. */ 915 debug("Requesting X11 forwarding with authentication spoofing."); 916 x11_request_forwarding_with_spoofing(0, proto, data); 917 918 /* Read response from the server. */ 919 type = packet_read(&plen); 920 if (type == SSH_SMSG_SUCCESS) { 921 interactive = 1; 922 } else if (type == SSH_SMSG_FAILURE) { 923 log("Warning: Remote host denied X11 forwarding."); 924 } else { 925 packet_disconnect("Protocol error waiting for X11 forwarding"); 926 } 927 } 928 /* Tell the packet module whether this is an interactive session. */ 929 packet_set_interactive(interactive); 930 931 /* Request authentication agent forwarding if appropriate. */ 932 check_agent_present(); 933 934 if (options.forward_agent) { 935 debug("Requesting authentication agent forwarding."); 936 auth_request_forwarding(); 937 938 /* Read response from the server. */ 939 type = packet_read(&plen); 940 packet_integrity_check(plen, 0, type); 941 if (type != SSH_SMSG_SUCCESS) 942 log("Warning: Remote host denied authentication agent forwarding."); 943 } 944 945 /* Initiate port forwardings. */ 946 ssh_init_forwarding(); 947 948 /* If requested, let ssh continue in the background. */ 949 if (fork_after_authentication_flag) 950 if (daemon(1, 1) < 0) 951 fatal("daemon() failed: %.200s", strerror(errno)); 952 953 /* 954 * If a command was specified on the command line, execute the 955 * command now. Otherwise request the server to start a shell. 956 */ 957 if (buffer_len(&command) > 0) { 958 int len = buffer_len(&command); 959 if (len > 900) 960 len = 900; 961 debug("Sending command: %.*s", len, buffer_ptr(&command)); 962 packet_start(SSH_CMSG_EXEC_CMD); 963 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 964 packet_send(); 965 packet_write_wait(); 966 } else { 967 debug("Requesting shell."); 968 packet_start(SSH_CMSG_EXEC_SHELL); 969 packet_send(); 970 packet_write_wait(); 971 } 972 973 /* Enter the interactive session. */ 974 return client_loop(have_tty, tty_flag ? 975 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 976 } 977 978 static void 979 client_subsystem_reply(int type, int plen, void *ctxt) 980 { 981 int id, len; 982 983 id = packet_get_int(); 984 len = buffer_len(&command); 985 if (len > 900) 986 len = 900; 987 packet_done(); 988 if (type == SSH2_MSG_CHANNEL_FAILURE) 989 fatal("Request for subsystem '%.*s' failed on channel %d", 990 len, buffer_ptr(&command), id); 991 } 992 993 static void 994 ssh_session2_callback(int id, void *arg) 995 { 996 int len; 997 int interactive = 0; 998 struct termios tio; 999 1000 debug("client_init id %d arg %ld", id, (long)arg); 1001 1002 if (tty_flag) { 1003 struct winsize ws; 1004 char *cp; 1005 cp = getenv("TERM"); 1006 if (!cp) 1007 cp = ""; 1008 /* Store window size in the packet. */ 1009 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1010 memset(&ws, 0, sizeof(ws)); 1011 1012 channel_request_start(id, "pty-req", 0); 1013 packet_put_cstring(cp); 1014 packet_put_int(ws.ws_col); 1015 packet_put_int(ws.ws_row); 1016 packet_put_int(ws.ws_xpixel); 1017 packet_put_int(ws.ws_ypixel); 1018 tio = get_saved_tio(); 1019 tty_make_modes(/*ignored*/ 0, &tio); 1020 packet_send(); 1021 interactive = 1; 1022 /* XXX wait for reply */ 1023 } 1024 if (options.forward_x11 && 1025 getenv("DISPLAY") != NULL) { 1026 char proto[512], data[512]; 1027 /* Get reasonable local authentication information. */ 1028 x11_get_proto(proto, sizeof proto, data, sizeof data); 1029 /* Request forwarding with authentication spoofing. */ 1030 debug("Requesting X11 forwarding with authentication spoofing."); 1031 x11_request_forwarding_with_spoofing(id, proto, data); 1032 interactive = 1; 1033 /* XXX wait for reply */ 1034 } 1035 1036 check_agent_present(); 1037 if (options.forward_agent) { 1038 debug("Requesting authentication agent forwarding."); 1039 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1040 packet_send(); 1041 } 1042 1043 len = buffer_len(&command); 1044 if (len > 0) { 1045 if (len > 900) 1046 len = 900; 1047 if (subsystem_flag) { 1048 debug("Sending subsystem: %.*s", len, buffer_ptr(&command)); 1049 channel_request_start(id, "subsystem", /*want reply*/ 1); 1050 /* register callback for reply */ 1051 /* XXX we asume that client_loop has already been called */ 1052 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply); 1053 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply); 1054 } else { 1055 debug("Sending command: %.*s", len, buffer_ptr(&command)); 1056 channel_request_start(id, "exec", 0); 1057 } 1058 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1059 packet_send(); 1060 } else { 1061 channel_request(id, "shell", 0); 1062 } 1063 /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */ 1064 1065 /* register different callback, etc. XXX */ 1066 packet_set_interactive(interactive); 1067 } 1068 1069 static int 1070 ssh_session2_command(void) 1071 { 1072 Channel *c; 1073 int window, packetmax, in, out, err; 1074 1075 if (stdin_null_flag) { 1076 in = open(_PATH_DEVNULL, O_RDONLY); 1077 } else { 1078 in = dup(STDIN_FILENO); 1079 } 1080 out = dup(STDOUT_FILENO); 1081 err = dup(STDERR_FILENO); 1082 1083 if (in < 0 || out < 0 || err < 0) 1084 fatal("dup() in/out/err failed"); 1085 1086 /* enable nonblocking unless tty */ 1087 if (!isatty(in)) 1088 set_nonblock(in); 1089 if (!isatty(out)) 1090 set_nonblock(out); 1091 if (!isatty(err)) 1092 set_nonblock(err); 1093 1094 window = CHAN_SES_WINDOW_DEFAULT; 1095 packetmax = CHAN_SES_PACKET_DEFAULT; 1096 if (!tty_flag) { 1097 window *= 2; 1098 packetmax *=2; 1099 } 1100 c = channel_new( 1101 "session", SSH_CHANNEL_OPENING, in, out, err, 1102 window, packetmax, CHAN_EXTENDED_WRITE, 1103 xstrdup("client-session"), /*nonblock*/0); 1104 if (c == NULL) 1105 fatal("ssh_session2_command: channel_new failed"); 1106 1107 debug3("ssh_session2_command: channel_new: %d", c->self); 1108 1109 channel_send_open(c->self); 1110 channel_register_callback(c->self, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, 1111 ssh_session2_callback, (void *)0); 1112 1113 return c->self; 1114 } 1115 1116 static int 1117 ssh_session2(void) 1118 { 1119 int id; 1120 1121 /* XXX should be pre-session */ 1122 ssh_init_forwarding(); 1123 1124 id = no_shell_flag ? -1 : ssh_session2_command(); 1125 1126 /* If requested, let ssh continue in the background. */ 1127 if (fork_after_authentication_flag) 1128 if (daemon(1, 1) < 0) 1129 fatal("daemon() failed: %.200s", strerror(errno)); 1130 1131 return client_loop(tty_flag, tty_flag ? 1132 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1133 } 1134 1135 static void 1136 load_public_identity_files(void) 1137 { 1138 char *filename; 1139 Key *public; 1140 int i = 0; 1141 1142 #ifdef SMARTCARD 1143 if (options.smartcard_device != NULL && 1144 options.num_identity_files + 1 < SSH_MAX_IDENTITY_FILES && 1145 (public = sc_get_key(options.smartcard_device)) != NULL ) { 1146 Key *new; 1147 1148 if (options.num_identity_files + 2 > SSH_MAX_IDENTITY_FILES) 1149 options.num_identity_files = SSH_MAX_IDENTITY_FILES - 2; 1150 memmove(&options.identity_files[2], &options.identity_files[0], 1151 sizeof(char *) * options.num_identity_files); 1152 options.num_identity_files += 2; 1153 i = 2; 1154 1155 /* XXX ssh1 vs ssh2 */ 1156 new = key_new(KEY_RSA); 1157 new->flags = KEY_FLAG_EXT; 1158 BN_copy(new->rsa->n, public->rsa->n); 1159 BN_copy(new->rsa->e, public->rsa->e); 1160 RSA_set_method(new->rsa, sc_get_engine()); 1161 options.identity_keys[0] = new; 1162 options.identity_files[0] = xstrdup("smartcard rsa key");; 1163 1164 new = key_new(KEY_RSA1); 1165 new->flags = KEY_FLAG_EXT; 1166 BN_copy(new->rsa->n, public->rsa->n); 1167 BN_copy(new->rsa->e, public->rsa->e); 1168 RSA_set_method(new->rsa, sc_get_engine()); 1169 options.identity_keys[1] = new; 1170 options.identity_files[1] = xstrdup("smartcard rsa1 key"); 1171 1172 key_free(public); 1173 } 1174 #endif /* SMARTCARD */ 1175 for (; i < options.num_identity_files; i++) { 1176 filename = tilde_expand_filename(options.identity_files[i], 1177 original_real_uid); 1178 public = key_load_public(filename, NULL); 1179 debug("identity file %s type %d", filename, 1180 public ? public->type : -1); 1181 xfree(options.identity_files[i]); 1182 options.identity_files[i] = filename; 1183 options.identity_keys[i] = public; 1184 } 1185 } 1186