1 /* $OpenBSD: ssh.c,v 1.371 2013/02/17 23:16:57 dtucker Exp $ */ 2 /* $FreeBSD$ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * Ssh client program. This program can be used to log into a remote machine. 8 * The software supports strong authentication, encryption, and forwarding 9 * of X11, TCP/IP, and authentication connections. 10 * 11 * As far as I am concerned, the code I have written for this software 12 * can be used freely for any purpose. Any derived versions of this 13 * software must be clearly marked as such, and if the derived work is 14 * incompatible with the protocol description in the RFC file, it must be 15 * called by a name other than "ssh" or "Secure Shell". 16 * 17 * Copyright (c) 1999 Niels Provos. All rights reserved. 18 * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved. 19 * 20 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu> 21 * in Canada (German citizen). 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the above copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 33 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 34 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 35 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 36 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 38 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 39 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 41 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 42 */ 43 44 #include "includes.h" 45 __RCSID("$FreeBSD$"); 46 47 #include <sys/types.h> 48 #ifdef HAVE_SYS_STAT_H 49 # include <sys/stat.h> 50 #endif 51 #include <sys/resource.h> 52 #include <sys/ioctl.h> 53 #include <sys/param.h> 54 #include <sys/socket.h> 55 #include <sys/wait.h> 56 57 #include <ctype.h> 58 #include <errno.h> 59 #include <fcntl.h> 60 #include <netdb.h> 61 #ifdef HAVE_PATHS_H 62 #include <paths.h> 63 #endif 64 #include <pwd.h> 65 #include <signal.h> 66 #include <stdarg.h> 67 #include <stddef.h> 68 #include <stdio.h> 69 #include <stdlib.h> 70 #include <string.h> 71 #include <unistd.h> 72 73 #include <netinet/in.h> 74 #include <arpa/inet.h> 75 76 #include <openssl/evp.h> 77 #include <openssl/err.h> 78 #include "openbsd-compat/openssl-compat.h" 79 #include "openbsd-compat/sys-queue.h" 80 81 #include "xmalloc.h" 82 #include "ssh.h" 83 #include "ssh1.h" 84 #include "ssh2.h" 85 #include "canohost.h" 86 #include "compat.h" 87 #include "cipher.h" 88 #include "packet.h" 89 #include "buffer.h" 90 #include "channels.h" 91 #include "key.h" 92 #include "authfd.h" 93 #include "authfile.h" 94 #include "pathnames.h" 95 #include "dispatch.h" 96 #include "clientloop.h" 97 #include "log.h" 98 #include "readconf.h" 99 #include "sshconnect.h" 100 #include "misc.h" 101 #include "kex.h" 102 #include "mac.h" 103 #include "sshpty.h" 104 #include "match.h" 105 #include "msg.h" 106 #include "uidswap.h" 107 #include "roaming.h" 108 #include "version.h" 109 110 #ifdef ENABLE_PKCS11 111 #include "ssh-pkcs11.h" 112 #endif 113 114 extern char *__progname; 115 116 /* Saves a copy of argv for setproctitle emulation */ 117 #ifndef HAVE_SETPROCTITLE 118 static char **saved_av; 119 #endif 120 121 /* Flag indicating whether debug mode is on. May be set on the command line. */ 122 int debug_flag = 0; 123 124 /* Flag indicating whether a tty should be requested */ 125 int tty_flag = 0; 126 127 /* don't exec a shell */ 128 int no_shell_flag = 0; 129 130 /* 131 * Flag indicating that nothing should be read from stdin. This can be set 132 * on the command line. 133 */ 134 int stdin_null_flag = 0; 135 136 /* 137 * Flag indicating that the current process should be backgrounded and 138 * a new slave launched in the foreground for ControlPersist. 139 */ 140 int need_controlpersist_detach = 0; 141 142 /* Copies of flags for ControlPersist foreground slave */ 143 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty; 144 145 /* 146 * Flag indicating that ssh should fork after authentication. This is useful 147 * so that the passphrase can be entered manually, and then ssh goes to the 148 * background. 149 */ 150 int fork_after_authentication_flag = 0; 151 152 /* forward stdio to remote host and port */ 153 char *stdio_forward_host = NULL; 154 int stdio_forward_port = 0; 155 156 /* 157 * General data structure for command line options and options configurable 158 * in configuration files. See readconf.h. 159 */ 160 Options options; 161 162 /* optional user configfile */ 163 char *config = NULL; 164 165 /* 166 * Name of the host we are connecting to. This is the name given on the 167 * command line, or the HostName specified for the user-supplied name in a 168 * configuration file. 169 */ 170 char *host; 171 172 /* socket address the host resolves to */ 173 struct sockaddr_storage hostaddr; 174 175 /* Private host keys. */ 176 Sensitive sensitive_data; 177 178 /* Original real UID. */ 179 uid_t original_real_uid; 180 uid_t original_effective_uid; 181 182 /* command to be executed */ 183 Buffer command; 184 185 /* Should we execute a command or invoke a subsystem? */ 186 int subsystem_flag = 0; 187 188 /* # of replies received for global requests */ 189 static int remote_forward_confirms_received = 0; 190 191 /* mux.c */ 192 extern int muxserver_sock; 193 extern u_int muxclient_command; 194 195 /* Prints a help message to the user. This function never returns. */ 196 197 static void 198 usage(void) 199 { 200 fprintf(stderr, 201 "usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" 202 " [-D [bind_address:]port] [-e escape_char] [-F configfile]\n" 203 " [-I pkcs11] [-i identity_file]\n" 204 " [-L [bind_address:]port:host:hostport]\n" 205 " [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n" 206 " [-R [bind_address:]port:host:hostport] [-S ctl_path]\n" 207 " [-W host:port] [-w local_tun[:remote_tun]]\n" 208 " [user@]hostname [command]\n" 209 ); 210 exit(255); 211 } 212 213 static int ssh_session(void); 214 static int ssh_session2(void); 215 static void load_public_identity_files(void); 216 static void main_sigchld_handler(int); 217 218 /* from muxclient.c */ 219 void muxclient(const char *); 220 void muxserver_listen(void); 221 222 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */ 223 static void 224 tilde_expand_paths(char **paths, u_int num_paths) 225 { 226 u_int i; 227 char *cp; 228 229 for (i = 0; i < num_paths; i++) { 230 cp = tilde_expand_filename(paths[i], original_real_uid); 231 xfree(paths[i]); 232 paths[i] = cp; 233 } 234 } 235 236 /* 237 * Main program for the ssh client. 238 */ 239 int 240 main(int ac, char **av) 241 { 242 int i, r, opt, exit_status, use_syslog; 243 char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg; 244 char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV]; 245 struct stat st; 246 struct passwd *pw; 247 int dummy, timeout_ms; 248 extern int optind, optreset; 249 extern char *optarg; 250 251 struct servent *sp; 252 Forward fwd; 253 254 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 255 sanitise_stdfd(); 256 257 __progname = ssh_get_progname(av[0]); 258 259 #ifndef HAVE_SETPROCTITLE 260 /* Prepare for later setproctitle emulation */ 261 /* Save argv so it isn't clobbered by setproctitle() emulation */ 262 saved_av = xcalloc(ac + 1, sizeof(*saved_av)); 263 for (i = 0; i < ac; i++) 264 saved_av[i] = xstrdup(av[i]); 265 saved_av[i] = NULL; 266 compat_init_setproctitle(ac, av); 267 av = saved_av; 268 #endif 269 270 /* 271 * Discard other fds that are hanging around. These can cause problem 272 * with backgrounded ssh processes started by ControlPersist. 273 */ 274 closefrom(STDERR_FILENO + 1); 275 276 /* 277 * Save the original real uid. It will be needed later (uid-swapping 278 * may clobber the real uid). 279 */ 280 original_real_uid = getuid(); 281 original_effective_uid = geteuid(); 282 283 /* 284 * Use uid-swapping to give up root privileges for the duration of 285 * option processing. We will re-instantiate the rights when we are 286 * ready to create the privileged port, and will permanently drop 287 * them when the port has been created (actually, when the connection 288 * has been made, as we may need to create the port several times). 289 */ 290 PRIV_END; 291 292 #ifdef HAVE_SETRLIMIT 293 /* If we are installed setuid root be careful to not drop core. */ 294 if (original_real_uid != original_effective_uid) { 295 struct rlimit rlim; 296 rlim.rlim_cur = rlim.rlim_max = 0; 297 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 298 fatal("setrlimit failed: %.100s", strerror(errno)); 299 } 300 #endif 301 /* Get user data. */ 302 pw = getpwuid(original_real_uid); 303 if (!pw) { 304 logit("You don't exist, go away!"); 305 exit(255); 306 } 307 /* Take a copy of the returned structure. */ 308 pw = pwcopy(pw); 309 310 /* 311 * Set our umask to something reasonable, as some files are created 312 * with the default umask. This will make them world-readable but 313 * writable only by the owner, which is ok for all files for which we 314 * don't set the modes explicitly. 315 */ 316 umask(022); 317 318 /* 319 * Initialize option structure to indicate that no values have been 320 * set. 321 */ 322 initialize_options(&options); 323 324 /* Parse command-line arguments. */ 325 host = NULL; 326 use_syslog = 0; 327 argv0 = av[0]; 328 329 again: 330 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 331 "ACD:F:I:KL:MNO:PR:S:TVw:W:XYy")) != -1) { 332 switch (opt) { 333 case '1': 334 options.protocol = SSH_PROTO_1; 335 break; 336 case '2': 337 options.protocol = SSH_PROTO_2; 338 break; 339 case '4': 340 options.address_family = AF_INET; 341 break; 342 case '6': 343 options.address_family = AF_INET6; 344 break; 345 case 'n': 346 stdin_null_flag = 1; 347 break; 348 case 'f': 349 fork_after_authentication_flag = 1; 350 stdin_null_flag = 1; 351 break; 352 case 'x': 353 options.forward_x11 = 0; 354 break; 355 case 'X': 356 options.forward_x11 = 1; 357 break; 358 case 'y': 359 use_syslog = 1; 360 break; 361 case 'Y': 362 options.forward_x11 = 1; 363 options.forward_x11_trusted = 1; 364 break; 365 case 'g': 366 options.gateway_ports = 1; 367 break; 368 case 'O': 369 if (stdio_forward_host != NULL) 370 fatal("Cannot specify multiplexing " 371 "command with -W"); 372 else if (muxclient_command != 0) 373 fatal("Multiplexing command already specified"); 374 if (strcmp(optarg, "check") == 0) 375 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; 376 else if (strcmp(optarg, "forward") == 0) 377 muxclient_command = SSHMUX_COMMAND_FORWARD; 378 else if (strcmp(optarg, "exit") == 0) 379 muxclient_command = SSHMUX_COMMAND_TERMINATE; 380 else if (strcmp(optarg, "stop") == 0) 381 muxclient_command = SSHMUX_COMMAND_STOP; 382 else if (strcmp(optarg, "cancel") == 0) 383 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD; 384 else 385 fatal("Invalid multiplex command."); 386 break; 387 case 'P': /* deprecated */ 388 options.use_privileged_port = 0; 389 break; 390 case 'a': 391 options.forward_agent = 0; 392 break; 393 case 'A': 394 options.forward_agent = 1; 395 break; 396 case 'k': 397 options.gss_deleg_creds = 0; 398 break; 399 case 'K': 400 options.gss_authentication = 1; 401 options.gss_deleg_creds = 1; 402 break; 403 case 'i': 404 if (stat(optarg, &st) < 0) { 405 fprintf(stderr, "Warning: Identity file %s " 406 "not accessible: %s.\n", optarg, 407 strerror(errno)); 408 break; 409 } 410 add_identity_file(&options, NULL, optarg, 1); 411 break; 412 case 'I': 413 #ifdef ENABLE_PKCS11 414 options.pkcs11_provider = xstrdup(optarg); 415 #else 416 fprintf(stderr, "no support for PKCS#11.\n"); 417 #endif 418 break; 419 case 't': 420 if (options.request_tty == REQUEST_TTY_YES) 421 options.request_tty = REQUEST_TTY_FORCE; 422 else 423 options.request_tty = REQUEST_TTY_YES; 424 break; 425 case 'v': 426 if (debug_flag == 0) { 427 debug_flag = 1; 428 options.log_level = SYSLOG_LEVEL_DEBUG1; 429 } else { 430 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 431 options.log_level++; 432 break; 433 } 434 /* FALLTHROUGH */ 435 case 'V': 436 if (options.version_addendum && 437 *options.version_addendum != '\0') 438 fprintf(stderr, "%s%s %s, %s\n", SSH_RELEASE, 439 options.hpn_disabled ? "" : SSH_VERSION_HPN, 440 options.version_addendum, 441 SSLeay_version(SSLEAY_VERSION)); 442 else 443 fprintf(stderr, "%s%s, %s\n", SSH_RELEASE, 444 options.hpn_disabled ? "" : SSH_VERSION_HPN, 445 SSLeay_version(SSLEAY_VERSION)); 446 if (opt == 'V') 447 exit(0); 448 break; 449 case 'w': 450 if (options.tun_open == -1) 451 options.tun_open = SSH_TUNMODE_DEFAULT; 452 options.tun_local = a2tun(optarg, &options.tun_remote); 453 if (options.tun_local == SSH_TUNID_ERR) { 454 fprintf(stderr, 455 "Bad tun device '%s'\n", optarg); 456 exit(255); 457 } 458 break; 459 case 'W': 460 if (stdio_forward_host != NULL) 461 fatal("stdio forward already specified"); 462 if (muxclient_command != 0) 463 fatal("Cannot specify stdio forward with -O"); 464 if (parse_forward(&fwd, optarg, 1, 0)) { 465 stdio_forward_host = fwd.listen_host; 466 stdio_forward_port = fwd.listen_port; 467 xfree(fwd.connect_host); 468 } else { 469 fprintf(stderr, 470 "Bad stdio forwarding specification '%s'\n", 471 optarg); 472 exit(255); 473 } 474 options.request_tty = REQUEST_TTY_NO; 475 no_shell_flag = 1; 476 options.clear_forwardings = 1; 477 options.exit_on_forward_failure = 1; 478 break; 479 case 'q': 480 options.log_level = SYSLOG_LEVEL_QUIET; 481 break; 482 case 'e': 483 if (optarg[0] == '^' && optarg[2] == 0 && 484 (u_char) optarg[1] >= 64 && 485 (u_char) optarg[1] < 128) 486 options.escape_char = (u_char) optarg[1] & 31; 487 else if (strlen(optarg) == 1) 488 options.escape_char = (u_char) optarg[0]; 489 else if (strcmp(optarg, "none") == 0) 490 options.escape_char = SSH_ESCAPECHAR_NONE; 491 else { 492 fprintf(stderr, "Bad escape character '%s'.\n", 493 optarg); 494 exit(255); 495 } 496 break; 497 case 'c': 498 if (ciphers_valid(optarg)) { 499 /* SSH2 only */ 500 options.ciphers = xstrdup(optarg); 501 options.cipher = SSH_CIPHER_INVALID; 502 } else { 503 /* SSH1 only */ 504 options.cipher = cipher_number(optarg); 505 if (options.cipher == -1) { 506 fprintf(stderr, 507 "Unknown cipher type '%s'\n", 508 optarg); 509 exit(255); 510 } 511 if (options.cipher == SSH_CIPHER_3DES) 512 options.ciphers = "3des-cbc"; 513 else if (options.cipher == SSH_CIPHER_BLOWFISH) 514 options.ciphers = "blowfish-cbc"; 515 else 516 options.ciphers = (char *)-1; 517 } 518 break; 519 case 'm': 520 if (mac_valid(optarg)) 521 options.macs = xstrdup(optarg); 522 else { 523 fprintf(stderr, "Unknown mac type '%s'\n", 524 optarg); 525 exit(255); 526 } 527 break; 528 case 'M': 529 if (options.control_master == SSHCTL_MASTER_YES) 530 options.control_master = SSHCTL_MASTER_ASK; 531 else 532 options.control_master = SSHCTL_MASTER_YES; 533 break; 534 case 'p': 535 options.port = a2port(optarg); 536 if (options.port <= 0) { 537 fprintf(stderr, "Bad port '%s'\n", optarg); 538 exit(255); 539 } 540 break; 541 case 'l': 542 options.user = optarg; 543 break; 544 545 case 'L': 546 if (parse_forward(&fwd, optarg, 0, 0)) 547 add_local_forward(&options, &fwd); 548 else { 549 fprintf(stderr, 550 "Bad local forwarding specification '%s'\n", 551 optarg); 552 exit(255); 553 } 554 break; 555 556 case 'R': 557 if (parse_forward(&fwd, optarg, 0, 1)) { 558 add_remote_forward(&options, &fwd); 559 } else { 560 fprintf(stderr, 561 "Bad remote forwarding specification " 562 "'%s'\n", optarg); 563 exit(255); 564 } 565 break; 566 567 case 'D': 568 if (parse_forward(&fwd, optarg, 1, 0)) { 569 add_local_forward(&options, &fwd); 570 } else { 571 fprintf(stderr, 572 "Bad dynamic forwarding specification " 573 "'%s'\n", optarg); 574 exit(255); 575 } 576 break; 577 578 case 'C': 579 options.compression = 1; 580 break; 581 case 'N': 582 no_shell_flag = 1; 583 options.request_tty = REQUEST_TTY_NO; 584 break; 585 case 'T': 586 options.request_tty = REQUEST_TTY_NO; 587 #ifdef NONE_CIPHER_ENABLED 588 /* 589 * Ensure that the user does not try to backdoor a 590 * NONE cipher switch on an interactive session by 591 * explicitly disabling it if the user asks for a 592 * session without a tty. 593 */ 594 options.none_switch = 0; 595 #endif 596 break; 597 case 'o': 598 dummy = 1; 599 line = xstrdup(optarg); 600 if (process_config_line(&options, host ? host : "", 601 line, "command-line", 0, &dummy) != 0) 602 exit(255); 603 xfree(line); 604 break; 605 case 's': 606 subsystem_flag = 1; 607 break; 608 case 'S': 609 if (options.control_path != NULL) 610 free(options.control_path); 611 options.control_path = xstrdup(optarg); 612 break; 613 case 'b': 614 options.bind_address = optarg; 615 break; 616 case 'F': 617 config = optarg; 618 break; 619 default: 620 usage(); 621 } 622 } 623 624 ac -= optind; 625 av += optind; 626 627 if (ac > 0 && !host) { 628 if (strrchr(*av, '@')) { 629 p = xstrdup(*av); 630 cp = strrchr(p, '@'); 631 if (cp == NULL || cp == p) 632 usage(); 633 options.user = p; 634 *cp = '\0'; 635 host = ++cp; 636 } else 637 host = *av; 638 if (ac > 1) { 639 optind = optreset = 1; 640 goto again; 641 } 642 ac--, av++; 643 } 644 645 /* Check that we got a host name. */ 646 if (!host) 647 usage(); 648 649 OpenSSL_add_all_algorithms(); 650 ERR_load_crypto_strings(); 651 652 /* Initialize the command to execute on remote host. */ 653 buffer_init(&command); 654 655 /* 656 * Save the command to execute on the remote host in a buffer. There 657 * is no limit on the length of the command, except by the maximum 658 * packet size. Also sets the tty flag if there is no command. 659 */ 660 if (!ac) { 661 /* No command specified - execute shell on a tty. */ 662 if (subsystem_flag) { 663 fprintf(stderr, 664 "You must specify a subsystem to invoke.\n"); 665 usage(); 666 } 667 } else { 668 /* A command has been specified. Store it into the buffer. */ 669 for (i = 0; i < ac; i++) { 670 if (i) 671 buffer_append(&command, " ", 1); 672 buffer_append(&command, av[i], strlen(av[i])); 673 } 674 } 675 676 /* Cannot fork to background if no command. */ 677 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 678 !no_shell_flag) 679 fatal("Cannot fork into background without a command " 680 "to execute."); 681 682 /* 683 * Initialize "log" output. Since we are the client all output 684 * actually goes to stderr. 685 */ 686 log_init(argv0, 687 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 688 SYSLOG_FACILITY_USER, !use_syslog); 689 690 /* 691 * Read per-user configuration file. Ignore the system wide config 692 * file if the user specifies a config file on the command line. 693 */ 694 if (config != NULL) { 695 if (!read_config_file(config, host, &options, 0)) 696 fatal("Can't open user config file %.100s: " 697 "%.100s", config, strerror(errno)); 698 } else { 699 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, 700 _PATH_SSH_USER_CONFFILE); 701 if (r > 0 && (size_t)r < sizeof(buf)) 702 (void)read_config_file(buf, host, &options, 1); 703 704 /* Read systemwide configuration file after user config. */ 705 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, 706 &options, 0); 707 } 708 709 /* Fill configuration defaults. */ 710 fill_default_options(&options); 711 712 channel_set_af(options.address_family); 713 714 /* reinit */ 715 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 716 717 if (options.request_tty == REQUEST_TTY_YES || 718 options.request_tty == REQUEST_TTY_FORCE) 719 tty_flag = 1; 720 721 /* Allocate a tty by default if no command specified. */ 722 if (buffer_len(&command) == 0) 723 tty_flag = options.request_tty != REQUEST_TTY_NO; 724 725 /* Force no tty */ 726 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0) 727 tty_flag = 0; 728 /* Do not allocate a tty if stdin is not a tty. */ 729 if ((!isatty(fileno(stdin)) || stdin_null_flag) && 730 options.request_tty != REQUEST_TTY_FORCE) { 731 if (tty_flag) 732 logit("Pseudo-terminal will not be allocated because " 733 "stdin is not a terminal."); 734 tty_flag = 0; 735 } 736 737 seed_rng(); 738 739 if (options.user == NULL) 740 options.user = xstrdup(pw->pw_name); 741 742 /* Get default port if port has not been set. */ 743 if (options.port == 0) { 744 sp = getservbyname(SSH_SERVICE_NAME, "tcp"); 745 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; 746 } 747 748 /* preserve host name given on command line for %n expansion */ 749 host_arg = host; 750 if (options.hostname != NULL) { 751 host = percent_expand(options.hostname, 752 "h", host, (char *)NULL); 753 } 754 755 if (gethostname(thishost, sizeof(thishost)) == -1) 756 fatal("gethostname: %s", strerror(errno)); 757 strlcpy(shorthost, thishost, sizeof(shorthost)); 758 shorthost[strcspn(thishost, ".")] = '\0'; 759 snprintf(portstr, sizeof(portstr), "%d", options.port); 760 761 if (options.local_command != NULL) { 762 debug3("expanding LocalCommand: %s", options.local_command); 763 cp = options.local_command; 764 options.local_command = percent_expand(cp, "d", pw->pw_dir, 765 "h", host, "l", thishost, "n", host_arg, "r", options.user, 766 "p", portstr, "u", pw->pw_name, "L", shorthost, 767 (char *)NULL); 768 debug3("expanded LocalCommand: %s", options.local_command); 769 xfree(cp); 770 } 771 772 /* Find canonic host name. */ 773 if (strchr(host, '.') == 0) { 774 struct addrinfo hints; 775 struct addrinfo *ai = NULL; 776 int errgai; 777 memset(&hints, 0, sizeof(hints)); 778 hints.ai_family = options.address_family; 779 hints.ai_flags = AI_CANONNAME; 780 hints.ai_socktype = SOCK_STREAM; 781 errgai = getaddrinfo(host, NULL, &hints, &ai); 782 if (errgai == 0) { 783 if (ai->ai_canonname != NULL) 784 host = xstrdup(ai->ai_canonname); 785 freeaddrinfo(ai); 786 } 787 } 788 789 /* force lowercase for hostkey matching */ 790 if (options.host_key_alias != NULL) { 791 for (p = options.host_key_alias; *p; p++) 792 if (isupper(*p)) 793 *p = (char)tolower(*p); 794 } 795 796 if (options.proxy_command != NULL && 797 strcmp(options.proxy_command, "none") == 0) { 798 xfree(options.proxy_command); 799 options.proxy_command = NULL; 800 } 801 if (options.control_path != NULL && 802 strcmp(options.control_path, "none") == 0) { 803 xfree(options.control_path); 804 options.control_path = NULL; 805 } 806 807 if (options.control_path != NULL) { 808 cp = tilde_expand_filename(options.control_path, 809 original_real_uid); 810 xfree(options.control_path); 811 options.control_path = percent_expand(cp, "h", host, 812 "l", thishost, "n", host_arg, "r", options.user, 813 "p", portstr, "u", pw->pw_name, "L", shorthost, 814 (char *)NULL); 815 xfree(cp); 816 } 817 if (muxclient_command != 0 && options.control_path == NULL) 818 fatal("No ControlPath specified for \"-O\" command"); 819 if (options.control_path != NULL) 820 muxclient(options.control_path); 821 822 timeout_ms = options.connection_timeout * 1000; 823 824 /* Open a connection to the remote host. */ 825 if (ssh_connect(host, &hostaddr, options.port, 826 options.address_family, options.connection_attempts, &timeout_ms, 827 options.tcp_keep_alive, 828 #ifdef HAVE_CYGWIN 829 options.use_privileged_port, 830 #else 831 original_effective_uid == 0 && options.use_privileged_port, 832 #endif 833 options.proxy_command) != 0) 834 exit(255); 835 836 if (timeout_ms > 0) 837 debug3("timeout: %d ms remain after connect", timeout_ms); 838 839 /* 840 * If we successfully made the connection, load the host private key 841 * in case we will need it later for combined rsa-rhosts 842 * authentication. This must be done before releasing extra 843 * privileges, because the file is only readable by root. 844 * If we cannot access the private keys, load the public keys 845 * instead and try to execute the ssh-keysign helper instead. 846 */ 847 sensitive_data.nkeys = 0; 848 sensitive_data.keys = NULL; 849 sensitive_data.external_keysign = 0; 850 if (options.rhosts_rsa_authentication || 851 options.hostbased_authentication) { 852 sensitive_data.nkeys = 7; 853 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 854 sizeof(Key)); 855 for (i = 0; i < sensitive_data.nkeys; i++) 856 sensitive_data.keys[i] = NULL; 857 858 PRIV_START; 859 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 860 _PATH_HOST_KEY_FILE, "", NULL, NULL); 861 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA, 862 _PATH_HOST_DSA_KEY_FILE, "", NULL); 863 #ifdef OPENSSL_HAS_ECC 864 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA, 865 _PATH_HOST_ECDSA_KEY_FILE, "", NULL); 866 #endif 867 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA, 868 _PATH_HOST_RSA_KEY_FILE, "", NULL); 869 sensitive_data.keys[4] = key_load_private_type(KEY_DSA, 870 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 871 #ifdef OPENSSL_HAS_ECC 872 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA, 873 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL); 874 #endif 875 sensitive_data.keys[6] = key_load_private_type(KEY_RSA, 876 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 877 PRIV_END; 878 879 if (options.hostbased_authentication == 1 && 880 sensitive_data.keys[0] == NULL && 881 sensitive_data.keys[4] == NULL && 882 sensitive_data.keys[5] == NULL && 883 sensitive_data.keys[6] == NULL) { 884 sensitive_data.keys[1] = key_load_cert( 885 _PATH_HOST_DSA_KEY_FILE); 886 #ifdef OPENSSL_HAS_ECC 887 sensitive_data.keys[2] = key_load_cert( 888 _PATH_HOST_ECDSA_KEY_FILE); 889 #endif 890 sensitive_data.keys[3] = key_load_cert( 891 _PATH_HOST_RSA_KEY_FILE); 892 sensitive_data.keys[4] = key_load_public( 893 _PATH_HOST_DSA_KEY_FILE, NULL); 894 #ifdef OPENSSL_HAS_ECC 895 sensitive_data.keys[5] = key_load_public( 896 _PATH_HOST_ECDSA_KEY_FILE, NULL); 897 #endif 898 sensitive_data.keys[6] = key_load_public( 899 _PATH_HOST_RSA_KEY_FILE, NULL); 900 sensitive_data.external_keysign = 1; 901 } 902 } 903 /* 904 * Get rid of any extra privileges that we may have. We will no 905 * longer need them. Also, extra privileges could make it very hard 906 * to read identity files and other non-world-readable files from the 907 * user's home directory if it happens to be on a NFS volume where 908 * root is mapped to nobody. 909 */ 910 if (original_effective_uid == 0) { 911 PRIV_START; 912 permanently_set_uid(pw); 913 } 914 915 /* 916 * Now that we are back to our own permissions, create ~/.ssh 917 * directory if it doesn't already exist. 918 */ 919 if (config == NULL) { 920 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 921 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 922 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) { 923 #ifdef WITH_SELINUX 924 ssh_selinux_setfscreatecon(buf); 925 #endif 926 if (mkdir(buf, 0700) < 0) 927 error("Could not create directory '%.200s'.", 928 buf); 929 #ifdef WITH_SELINUX 930 ssh_selinux_setfscreatecon(NULL); 931 #endif 932 } 933 } 934 /* load options.identity_files */ 935 load_public_identity_files(); 936 937 /* Expand ~ in known host file names. */ 938 tilde_expand_paths(options.system_hostfiles, 939 options.num_system_hostfiles); 940 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles); 941 942 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 943 signal(SIGCHLD, main_sigchld_handler); 944 945 /* Log into the remote system. Never returns if the login fails. */ 946 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 947 options.port, pw, timeout_ms); 948 949 if (packet_connection_is_on_socket()) { 950 verbose("Authenticated to %s ([%s]:%d).", host, 951 get_remote_ipaddr(), get_remote_port()); 952 } else { 953 verbose("Authenticated to %s (via proxy).", host); 954 } 955 956 /* We no longer need the private host keys. Clear them now. */ 957 if (sensitive_data.nkeys != 0) { 958 for (i = 0; i < sensitive_data.nkeys; i++) { 959 if (sensitive_data.keys[i] != NULL) { 960 /* Destroys contents safely */ 961 debug3("clear hostkey %d", i); 962 key_free(sensitive_data.keys[i]); 963 sensitive_data.keys[i] = NULL; 964 } 965 } 966 xfree(sensitive_data.keys); 967 } 968 for (i = 0; i < options.num_identity_files; i++) { 969 if (options.identity_files[i]) { 970 xfree(options.identity_files[i]); 971 options.identity_files[i] = NULL; 972 } 973 if (options.identity_keys[i]) { 974 key_free(options.identity_keys[i]); 975 options.identity_keys[i] = NULL; 976 } 977 } 978 979 exit_status = compat20 ? ssh_session2() : ssh_session(); 980 packet_close(); 981 982 if (options.control_path != NULL && muxserver_sock != -1) 983 unlink(options.control_path); 984 985 /* Kill ProxyCommand if it is running. */ 986 ssh_kill_proxy_command(); 987 988 return exit_status; 989 } 990 991 static void 992 control_persist_detach(void) 993 { 994 pid_t pid; 995 int devnull; 996 997 debug("%s: backgrounding master process", __func__); 998 999 /* 1000 * master (current process) into the background, and make the 1001 * foreground process a client of the backgrounded master. 1002 */ 1003 switch ((pid = fork())) { 1004 case -1: 1005 fatal("%s: fork: %s", __func__, strerror(errno)); 1006 case 0: 1007 /* Child: master process continues mainloop */ 1008 break; 1009 default: 1010 /* Parent: set up mux slave to connect to backgrounded master */ 1011 debug2("%s: background process is %ld", __func__, (long)pid); 1012 stdin_null_flag = ostdin_null_flag; 1013 options.request_tty = orequest_tty; 1014 tty_flag = otty_flag; 1015 close(muxserver_sock); 1016 muxserver_sock = -1; 1017 options.control_master = SSHCTL_MASTER_NO; 1018 muxclient(options.control_path); 1019 /* muxclient() doesn't return on success. */ 1020 fatal("Failed to connect to new control master"); 1021 } 1022 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { 1023 error("%s: open(\"/dev/null\"): %s", __func__, 1024 strerror(errno)); 1025 } else { 1026 if (dup2(devnull, STDIN_FILENO) == -1 || 1027 dup2(devnull, STDOUT_FILENO) == -1) 1028 error("%s: dup2: %s", __func__, strerror(errno)); 1029 if (devnull > STDERR_FILENO) 1030 close(devnull); 1031 } 1032 setproctitle("%s [mux]", options.control_path); 1033 } 1034 1035 /* Do fork() after authentication. Used by "ssh -f" */ 1036 static void 1037 fork_postauth(void) 1038 { 1039 if (need_controlpersist_detach) 1040 control_persist_detach(); 1041 debug("forking to background"); 1042 fork_after_authentication_flag = 0; 1043 if (daemon(1, 1) < 0) 1044 fatal("daemon() failed: %.200s", strerror(errno)); 1045 } 1046 1047 /* Callback for remote forward global requests */ 1048 static void 1049 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 1050 { 1051 Forward *rfwd = (Forward *)ctxt; 1052 1053 /* XXX verbose() on failure? */ 1054 debug("remote forward %s for: listen %d, connect %s:%d", 1055 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 1056 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 1057 if (rfwd->listen_port == 0) { 1058 if (type == SSH2_MSG_REQUEST_SUCCESS) { 1059 rfwd->allocated_port = packet_get_int(); 1060 logit("Allocated port %u for remote forward to %s:%d", 1061 rfwd->allocated_port, 1062 rfwd->connect_host, rfwd->connect_port); 1063 channel_update_permitted_opens(rfwd->handle, 1064 rfwd->allocated_port); 1065 } else { 1066 channel_update_permitted_opens(rfwd->handle, -1); 1067 } 1068 } 1069 1070 if (type == SSH2_MSG_REQUEST_FAILURE) { 1071 if (options.exit_on_forward_failure) 1072 fatal("Error: remote port forwarding failed for " 1073 "listen port %d", rfwd->listen_port); 1074 else 1075 logit("Warning: remote port forwarding failed for " 1076 "listen port %d", rfwd->listen_port); 1077 } 1078 if (++remote_forward_confirms_received == options.num_remote_forwards) { 1079 debug("All remote forwarding requests processed"); 1080 if (fork_after_authentication_flag) 1081 fork_postauth(); 1082 } 1083 } 1084 1085 static void 1086 client_cleanup_stdio_fwd(int id, void *arg) 1087 { 1088 debug("stdio forwarding: done"); 1089 cleanup_exit(0); 1090 } 1091 1092 static void 1093 ssh_init_stdio_forwarding(void) 1094 { 1095 Channel *c; 1096 int in, out; 1097 1098 if (stdio_forward_host == NULL) 1099 return; 1100 if (!compat20) 1101 fatal("stdio forwarding require Protocol 2"); 1102 1103 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port); 1104 1105 if ((in = dup(STDIN_FILENO)) < 0 || 1106 (out = dup(STDOUT_FILENO)) < 0) 1107 fatal("channel_connect_stdio_fwd: dup() in/out failed"); 1108 if ((c = channel_connect_stdio_fwd(stdio_forward_host, 1109 stdio_forward_port, in, out)) == NULL) 1110 fatal("%s: channel_connect_stdio_fwd failed", __func__); 1111 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0); 1112 } 1113 1114 static void 1115 ssh_init_forwarding(void) 1116 { 1117 int success = 0; 1118 int i; 1119 1120 /* Initiate local TCP/IP port forwardings. */ 1121 for (i = 0; i < options.num_local_forwards; i++) { 1122 debug("Local connections to %.200s:%d forwarded to remote " 1123 "address %.200s:%d", 1124 (options.local_forwards[i].listen_host == NULL) ? 1125 (options.gateway_ports ? "*" : "LOCALHOST") : 1126 options.local_forwards[i].listen_host, 1127 options.local_forwards[i].listen_port, 1128 options.local_forwards[i].connect_host, 1129 options.local_forwards[i].connect_port); 1130 success += channel_setup_local_fwd_listener( 1131 options.local_forwards[i].listen_host, 1132 options.local_forwards[i].listen_port, 1133 options.local_forwards[i].connect_host, 1134 options.local_forwards[i].connect_port, 1135 options.gateway_ports); 1136 } 1137 if (i > 0 && success != i && options.exit_on_forward_failure) 1138 fatal("Could not request local forwarding."); 1139 if (i > 0 && success == 0) 1140 error("Could not request local forwarding."); 1141 1142 /* Initiate remote TCP/IP port forwardings. */ 1143 for (i = 0; i < options.num_remote_forwards; i++) { 1144 debug("Remote connections from %.200s:%d forwarded to " 1145 "local address %.200s:%d", 1146 (options.remote_forwards[i].listen_host == NULL) ? 1147 "LOCALHOST" : options.remote_forwards[i].listen_host, 1148 options.remote_forwards[i].listen_port, 1149 options.remote_forwards[i].connect_host, 1150 options.remote_forwards[i].connect_port); 1151 options.remote_forwards[i].handle = 1152 channel_request_remote_forwarding( 1153 options.remote_forwards[i].listen_host, 1154 options.remote_forwards[i].listen_port, 1155 options.remote_forwards[i].connect_host, 1156 options.remote_forwards[i].connect_port); 1157 if (options.remote_forwards[i].handle < 0) { 1158 if (options.exit_on_forward_failure) 1159 fatal("Could not request remote forwarding."); 1160 else 1161 logit("Warning: Could not request remote " 1162 "forwarding."); 1163 } else { 1164 client_register_global_confirm(ssh_confirm_remote_forward, 1165 &options.remote_forwards[i]); 1166 } 1167 } 1168 1169 /* Initiate tunnel forwarding. */ 1170 if (options.tun_open != SSH_TUNMODE_NO) { 1171 if (client_request_tun_fwd(options.tun_open, 1172 options.tun_local, options.tun_remote) == -1) { 1173 if (options.exit_on_forward_failure) 1174 fatal("Could not request tunnel forwarding."); 1175 else 1176 error("Could not request tunnel forwarding."); 1177 } 1178 } 1179 } 1180 1181 static void 1182 check_agent_present(void) 1183 { 1184 if (options.forward_agent) { 1185 /* Clear agent forwarding if we don't have an agent. */ 1186 if (!ssh_agent_present()) 1187 options.forward_agent = 0; 1188 } 1189 } 1190 1191 static int 1192 ssh_session(void) 1193 { 1194 int type; 1195 int interactive = 0; 1196 int have_tty = 0; 1197 struct winsize ws; 1198 char *cp; 1199 const char *display; 1200 1201 /* Enable compression if requested. */ 1202 if (options.compression) { 1203 debug("Requesting compression at level %d.", 1204 options.compression_level); 1205 1206 if (options.compression_level < 1 || 1207 options.compression_level > 9) 1208 fatal("Compression level must be from 1 (fast) to " 1209 "9 (slow, best)."); 1210 1211 /* Send the request. */ 1212 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 1213 packet_put_int(options.compression_level); 1214 packet_send(); 1215 packet_write_wait(); 1216 type = packet_read(); 1217 if (type == SSH_SMSG_SUCCESS) 1218 packet_start_compression(options.compression_level); 1219 else if (type == SSH_SMSG_FAILURE) 1220 logit("Warning: Remote host refused compression."); 1221 else 1222 packet_disconnect("Protocol error waiting for " 1223 "compression response."); 1224 } 1225 /* Allocate a pseudo tty if appropriate. */ 1226 if (tty_flag) { 1227 debug("Requesting pty."); 1228 1229 /* Start the packet. */ 1230 packet_start(SSH_CMSG_REQUEST_PTY); 1231 1232 /* Store TERM in the packet. There is no limit on the 1233 length of the string. */ 1234 cp = getenv("TERM"); 1235 if (!cp) 1236 cp = ""; 1237 packet_put_cstring(cp); 1238 1239 /* Store window size in the packet. */ 1240 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1241 memset(&ws, 0, sizeof(ws)); 1242 packet_put_int((u_int)ws.ws_row); 1243 packet_put_int((u_int)ws.ws_col); 1244 packet_put_int((u_int)ws.ws_xpixel); 1245 packet_put_int((u_int)ws.ws_ypixel); 1246 1247 /* Store tty modes in the packet. */ 1248 tty_make_modes(fileno(stdin), NULL); 1249 1250 /* Send the packet, and wait for it to leave. */ 1251 packet_send(); 1252 packet_write_wait(); 1253 1254 /* Read response from the server. */ 1255 type = packet_read(); 1256 if (type == SSH_SMSG_SUCCESS) { 1257 interactive = 1; 1258 have_tty = 1; 1259 } else if (type == SSH_SMSG_FAILURE) 1260 logit("Warning: Remote host failed or refused to " 1261 "allocate a pseudo tty."); 1262 else 1263 packet_disconnect("Protocol error waiting for pty " 1264 "request response."); 1265 } 1266 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1267 display = getenv("DISPLAY"); 1268 if (options.forward_x11 && display != NULL) { 1269 char *proto, *data; 1270 /* Get reasonable local authentication information. */ 1271 client_x11_get_proto(display, options.xauth_location, 1272 options.forward_x11_trusted, 1273 options.forward_x11_timeout, 1274 &proto, &data); 1275 /* Request forwarding with authentication spoofing. */ 1276 debug("Requesting X11 forwarding with authentication " 1277 "spoofing."); 1278 x11_request_forwarding_with_spoofing(0, display, proto, 1279 data, 0); 1280 /* Read response from the server. */ 1281 type = packet_read(); 1282 if (type == SSH_SMSG_SUCCESS) { 1283 interactive = 1; 1284 } else if (type == SSH_SMSG_FAILURE) { 1285 logit("Warning: Remote host denied X11 forwarding."); 1286 } else { 1287 packet_disconnect("Protocol error waiting for X11 " 1288 "forwarding"); 1289 } 1290 } 1291 /* Tell the packet module whether this is an interactive session. */ 1292 packet_set_interactive(interactive, 1293 options.ip_qos_interactive, options.ip_qos_bulk); 1294 1295 /* Request authentication agent forwarding if appropriate. */ 1296 check_agent_present(); 1297 1298 if (options.forward_agent) { 1299 debug("Requesting authentication agent forwarding."); 1300 auth_request_forwarding(); 1301 1302 /* Read response from the server. */ 1303 type = packet_read(); 1304 packet_check_eom(); 1305 if (type != SSH_SMSG_SUCCESS) 1306 logit("Warning: Remote host denied authentication agent forwarding."); 1307 } 1308 1309 /* Initiate port forwardings. */ 1310 ssh_init_stdio_forwarding(); 1311 ssh_init_forwarding(); 1312 1313 /* Execute a local command */ 1314 if (options.local_command != NULL && 1315 options.permit_local_command) 1316 ssh_local_cmd(options.local_command); 1317 1318 /* 1319 * If requested and we are not interested in replies to remote 1320 * forwarding requests, then let ssh continue in the background. 1321 */ 1322 if (fork_after_authentication_flag) { 1323 if (options.exit_on_forward_failure && 1324 options.num_remote_forwards > 0) { 1325 debug("deferring postauth fork until remote forward " 1326 "confirmation received"); 1327 } else 1328 fork_postauth(); 1329 } 1330 1331 /* 1332 * If a command was specified on the command line, execute the 1333 * command now. Otherwise request the server to start a shell. 1334 */ 1335 if (buffer_len(&command) > 0) { 1336 int len = buffer_len(&command); 1337 if (len > 900) 1338 len = 900; 1339 debug("Sending command: %.*s", len, 1340 (u_char *)buffer_ptr(&command)); 1341 packet_start(SSH_CMSG_EXEC_CMD); 1342 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1343 packet_send(); 1344 packet_write_wait(); 1345 } else { 1346 debug("Requesting shell."); 1347 packet_start(SSH_CMSG_EXEC_SHELL); 1348 packet_send(); 1349 packet_write_wait(); 1350 } 1351 1352 /* Enter the interactive session. */ 1353 return client_loop(have_tty, tty_flag ? 1354 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1355 } 1356 1357 /* request pty/x11/agent/tcpfwd/shell for channel */ 1358 static void 1359 ssh_session2_setup(int id, int success, void *arg) 1360 { 1361 extern char **environ; 1362 const char *display; 1363 int interactive = tty_flag; 1364 1365 if (!success) 1366 return; /* No need for error message, channels code sens one */ 1367 1368 display = getenv("DISPLAY"); 1369 if (options.forward_x11 && display != NULL) { 1370 char *proto, *data; 1371 /* Get reasonable local authentication information. */ 1372 client_x11_get_proto(display, options.xauth_location, 1373 options.forward_x11_trusted, 1374 options.forward_x11_timeout, &proto, &data); 1375 /* Request forwarding with authentication spoofing. */ 1376 debug("Requesting X11 forwarding with authentication " 1377 "spoofing."); 1378 x11_request_forwarding_with_spoofing(id, display, proto, 1379 data, 1); 1380 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); 1381 /* XXX exit_on_forward_failure */ 1382 interactive = 1; 1383 } 1384 1385 check_agent_present(); 1386 if (options.forward_agent) { 1387 debug("Requesting authentication agent forwarding."); 1388 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1389 packet_send(); 1390 } 1391 1392 /* Tell the packet module whether this is an interactive session. */ 1393 packet_set_interactive(interactive, 1394 options.ip_qos_interactive, options.ip_qos_bulk); 1395 1396 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1397 NULL, fileno(stdin), &command, environ); 1398 } 1399 1400 /* open new channel for a session */ 1401 static int 1402 ssh_session2_open(void) 1403 { 1404 Channel *c; 1405 int window, packetmax, in, out, err; 1406 1407 if (stdin_null_flag) { 1408 in = open(_PATH_DEVNULL, O_RDONLY); 1409 } else { 1410 in = dup(STDIN_FILENO); 1411 } 1412 out = dup(STDOUT_FILENO); 1413 err = dup(STDERR_FILENO); 1414 1415 if (in < 0 || out < 0 || err < 0) 1416 fatal("dup() in/out/err failed"); 1417 1418 /* enable nonblocking unless tty */ 1419 if (!isatty(in)) 1420 set_nonblock(in); 1421 if (!isatty(out)) 1422 set_nonblock(out); 1423 if (!isatty(err)) 1424 set_nonblock(err); 1425 1426 /* 1427 * We need to check to see what to do about buffer sizes here. 1428 * - In an HPN to non-HPN connection we want to limit the window size to 1429 * something reasonable in case the far side has the large window bug. 1430 * - In an HPN to HPN connection we want to use the max window size but 1431 * allow the user to override it. 1432 * - Lastly if HPN is disabled then use the ssh standard window size. 1433 * 1434 * We cannot just do a getsockopt() here and set the ssh window to that 1435 * as in case of autotuning of socket buffers the window would get stuck 1436 * at the initial buffer size, generally less than 96k. Therefore we 1437 * need to set the maximum ssh window size to the maximum HPN buffer 1438 * size unless the user has set TcpRcvBufPoll to no. In that case we 1439 * can just set the window to the minimum of HPN buffer size and TCP 1440 * receive buffer size. 1441 */ 1442 if (tty_flag) 1443 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT; 1444 else 1445 options.hpn_buffer_size = CHAN_HPN_MIN_WINDOW_DEFAULT; 1446 1447 if (datafellows & SSH_BUG_LARGEWINDOW) { 1448 debug("HPN to Non-HPN Connection"); 1449 } else if (options.tcp_rcv_buf_poll <= 0) { 1450 sock_get_rcvbuf(&options.hpn_buffer_size, 0); 1451 debug("HPNBufferSize set to TCP RWIN: %d", 1452 options.hpn_buffer_size); 1453 } else if (options.tcp_rcv_buf > 0) { 1454 sock_get_rcvbuf(&options.hpn_buffer_size, 1455 options.tcp_rcv_buf); 1456 debug("HPNBufferSize set to user TCPRcvBuf: %d", 1457 options.hpn_buffer_size); 1458 } 1459 debug("Final hpn_buffer_size = %d", options.hpn_buffer_size); 1460 channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size); 1461 window = options.hpn_buffer_size; 1462 1463 packetmax = CHAN_SES_PACKET_DEFAULT; 1464 if (tty_flag) { 1465 window = CHAN_SES_WINDOW_DEFAULT; 1466 window >>= 1; 1467 packetmax >>= 1; 1468 } 1469 c = channel_new( 1470 "session", SSH_CHANNEL_OPENING, in, out, err, 1471 window, packetmax, CHAN_EXTENDED_WRITE, 1472 "client-session", /*nonblock*/0); 1473 if (!options.hpn_disabled && options.tcp_rcv_buf_poll > 0) { 1474 c->dynamic_window = 1; 1475 debug("Enabled Dynamic Window Scaling\n"); 1476 } 1477 1478 debug3("ssh_session2_open: channel_new: %d", c->self); 1479 1480 channel_send_open(c->self); 1481 if (!no_shell_flag) 1482 channel_register_open_confirm(c->self, 1483 ssh_session2_setup, NULL); 1484 1485 return c->self; 1486 } 1487 1488 static int 1489 ssh_session2(void) 1490 { 1491 int id = -1; 1492 1493 /* XXX should be pre-session */ 1494 if (!options.control_persist) 1495 ssh_init_stdio_forwarding(); 1496 ssh_init_forwarding(); 1497 1498 /* Start listening for multiplex clients */ 1499 muxserver_listen(); 1500 1501 /* 1502 * If we are in control persist mode and have a working mux listen 1503 * socket, then prepare to background ourselves and have a foreground 1504 * client attach as a control slave. 1505 * NB. we must save copies of the flags that we override for 1506 * the backgrounding, since we defer attachment of the slave until 1507 * after the connection is fully established (in particular, 1508 * async rfwd replies have been received for ExitOnForwardFailure). 1509 */ 1510 if (options.control_persist && muxserver_sock != -1) { 1511 ostdin_null_flag = stdin_null_flag; 1512 ono_shell_flag = no_shell_flag; 1513 orequest_tty = options.request_tty; 1514 otty_flag = tty_flag; 1515 stdin_null_flag = 1; 1516 no_shell_flag = 1; 1517 tty_flag = 0; 1518 if (!fork_after_authentication_flag) 1519 need_controlpersist_detach = 1; 1520 fork_after_authentication_flag = 1; 1521 } 1522 /* 1523 * ControlPersist mux listen socket setup failed, attempt the 1524 * stdio forward setup that we skipped earlier. 1525 */ 1526 if (options.control_persist && muxserver_sock == -1) 1527 ssh_init_stdio_forwarding(); 1528 1529 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1530 id = ssh_session2_open(); 1531 1532 /* If we don't expect to open a new session, then disallow it */ 1533 if (options.control_master == SSHCTL_MASTER_NO && 1534 (datafellows & SSH_NEW_OPENSSH)) { 1535 debug("Requesting no-more-sessions@openssh.com"); 1536 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1537 packet_put_cstring("no-more-sessions@openssh.com"); 1538 packet_put_char(0); 1539 packet_send(); 1540 } 1541 1542 /* Execute a local command */ 1543 if (options.local_command != NULL && 1544 options.permit_local_command) 1545 ssh_local_cmd(options.local_command); 1546 1547 /* 1548 * If requested and we are not interested in replies to remote 1549 * forwarding requests, then let ssh continue in the background. 1550 */ 1551 if (fork_after_authentication_flag) { 1552 if (options.exit_on_forward_failure && 1553 options.num_remote_forwards > 0) { 1554 debug("deferring postauth fork until remote forward " 1555 "confirmation received"); 1556 } else 1557 fork_postauth(); 1558 } 1559 1560 if (options.use_roaming) 1561 request_roaming(); 1562 1563 return client_loop(tty_flag, tty_flag ? 1564 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1565 } 1566 1567 static void 1568 load_public_identity_files(void) 1569 { 1570 char *filename, *cp, thishost[NI_MAXHOST]; 1571 char *pwdir = NULL, *pwname = NULL; 1572 int i = 0; 1573 Key *public; 1574 struct passwd *pw; 1575 u_int n_ids; 1576 char *identity_files[SSH_MAX_IDENTITY_FILES]; 1577 Key *identity_keys[SSH_MAX_IDENTITY_FILES]; 1578 #ifdef ENABLE_PKCS11 1579 Key **keys; 1580 int nkeys; 1581 #endif /* PKCS11 */ 1582 1583 n_ids = 0; 1584 bzero(identity_files, sizeof(identity_files)); 1585 bzero(identity_keys, sizeof(identity_keys)); 1586 1587 #ifdef ENABLE_PKCS11 1588 if (options.pkcs11_provider != NULL && 1589 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1590 (pkcs11_init(!options.batch_mode) == 0) && 1591 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL, 1592 &keys)) > 0) { 1593 for (i = 0; i < nkeys; i++) { 1594 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1595 key_free(keys[i]); 1596 continue; 1597 } 1598 identity_keys[n_ids] = keys[i]; 1599 identity_files[n_ids] = 1600 xstrdup(options.pkcs11_provider); /* XXX */ 1601 n_ids++; 1602 } 1603 xfree(keys); 1604 } 1605 #endif /* ENABLE_PKCS11 */ 1606 if ((pw = getpwuid(original_real_uid)) == NULL) 1607 fatal("load_public_identity_files: getpwuid failed"); 1608 pwname = xstrdup(pw->pw_name); 1609 pwdir = xstrdup(pw->pw_dir); 1610 if (gethostname(thishost, sizeof(thishost)) == -1) 1611 fatal("load_public_identity_files: gethostname: %s", 1612 strerror(errno)); 1613 for (i = 0; i < options.num_identity_files; i++) { 1614 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1615 xfree(options.identity_files[i]); 1616 continue; 1617 } 1618 cp = tilde_expand_filename(options.identity_files[i], 1619 original_real_uid); 1620 filename = percent_expand(cp, "d", pwdir, 1621 "u", pwname, "l", thishost, "h", host, 1622 "r", options.user, (char *)NULL); 1623 xfree(cp); 1624 public = key_load_public(filename, NULL); 1625 debug("identity file %s type %d", filename, 1626 public ? public->type : -1); 1627 xfree(options.identity_files[i]); 1628 identity_files[n_ids] = filename; 1629 identity_keys[n_ids] = public; 1630 1631 if (++n_ids >= SSH_MAX_IDENTITY_FILES) 1632 continue; 1633 1634 /* Try to add the certificate variant too */ 1635 xasprintf(&cp, "%s-cert", filename); 1636 public = key_load_public(cp, NULL); 1637 debug("identity file %s type %d", cp, 1638 public ? public->type : -1); 1639 if (public == NULL) { 1640 xfree(cp); 1641 continue; 1642 } 1643 if (!key_is_cert(public)) { 1644 debug("%s: key %s type %s is not a certificate", 1645 __func__, cp, key_type(public)); 1646 key_free(public); 1647 xfree(cp); 1648 continue; 1649 } 1650 identity_keys[n_ids] = public; 1651 /* point to the original path, most likely the private key */ 1652 identity_files[n_ids] = xstrdup(filename); 1653 n_ids++; 1654 } 1655 options.num_identity_files = n_ids; 1656 memcpy(options.identity_files, identity_files, sizeof(identity_files)); 1657 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys)); 1658 1659 bzero(pwname, strlen(pwname)); 1660 xfree(pwname); 1661 bzero(pwdir, strlen(pwdir)); 1662 xfree(pwdir); 1663 } 1664 1665 static void 1666 main_sigchld_handler(int sig) 1667 { 1668 int save_errno = errno; 1669 pid_t pid; 1670 int status; 1671 1672 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 1673 (pid < 0 && errno == EINTR)) 1674 ; 1675 1676 signal(sig, main_sigchld_handler); 1677 errno = save_errno; 1678 } 1679 1680