1 /* $OpenBSD: ssh.c,v 1.370 2012/07/06 01:47:38 djm 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 if (options.num_identity_files >= 411 SSH_MAX_IDENTITY_FILES) 412 fatal("Too many identity files specified " 413 "(max %d)", SSH_MAX_IDENTITY_FILES); 414 options.identity_files[options.num_identity_files++] = 415 xstrdup(optarg); 416 break; 417 case 'I': 418 #ifdef ENABLE_PKCS11 419 options.pkcs11_provider = xstrdup(optarg); 420 #else 421 fprintf(stderr, "no support for PKCS#11.\n"); 422 #endif 423 break; 424 case 't': 425 if (options.request_tty == REQUEST_TTY_YES) 426 options.request_tty = REQUEST_TTY_FORCE; 427 else 428 options.request_tty = REQUEST_TTY_YES; 429 break; 430 case 'v': 431 if (debug_flag == 0) { 432 debug_flag = 1; 433 options.log_level = SYSLOG_LEVEL_DEBUG1; 434 } else { 435 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 436 options.log_level++; 437 break; 438 } 439 /* FALLTHROUGH */ 440 case 'V': 441 if (options.version_addendum && 442 *options.version_addendum != '\0') 443 fprintf(stderr, "%s%s %s, %s\n", SSH_RELEASE, 444 options.hpn_disabled ? "" : SSH_VERSION_HPN, 445 options.version_addendum, 446 SSLeay_version(SSLEAY_VERSION)); 447 else 448 fprintf(stderr, "%s%s, %s\n", SSH_RELEASE, 449 options.hpn_disabled ? "" : SSH_VERSION_HPN, 450 SSLeay_version(SSLEAY_VERSION)); 451 if (opt == 'V') 452 exit(0); 453 break; 454 case 'w': 455 if (options.tun_open == -1) 456 options.tun_open = SSH_TUNMODE_DEFAULT; 457 options.tun_local = a2tun(optarg, &options.tun_remote); 458 if (options.tun_local == SSH_TUNID_ERR) { 459 fprintf(stderr, 460 "Bad tun device '%s'\n", optarg); 461 exit(255); 462 } 463 break; 464 case 'W': 465 if (stdio_forward_host != NULL) 466 fatal("stdio forward already specified"); 467 if (muxclient_command != 0) 468 fatal("Cannot specify stdio forward with -O"); 469 if (parse_forward(&fwd, optarg, 1, 0)) { 470 stdio_forward_host = fwd.listen_host; 471 stdio_forward_port = fwd.listen_port; 472 xfree(fwd.connect_host); 473 } else { 474 fprintf(stderr, 475 "Bad stdio forwarding specification '%s'\n", 476 optarg); 477 exit(255); 478 } 479 options.request_tty = REQUEST_TTY_NO; 480 no_shell_flag = 1; 481 options.clear_forwardings = 1; 482 options.exit_on_forward_failure = 1; 483 break; 484 case 'q': 485 options.log_level = SYSLOG_LEVEL_QUIET; 486 break; 487 case 'e': 488 if (optarg[0] == '^' && optarg[2] == 0 && 489 (u_char) optarg[1] >= 64 && 490 (u_char) optarg[1] < 128) 491 options.escape_char = (u_char) optarg[1] & 31; 492 else if (strlen(optarg) == 1) 493 options.escape_char = (u_char) optarg[0]; 494 else if (strcmp(optarg, "none") == 0) 495 options.escape_char = SSH_ESCAPECHAR_NONE; 496 else { 497 fprintf(stderr, "Bad escape character '%s'.\n", 498 optarg); 499 exit(255); 500 } 501 break; 502 case 'c': 503 if (ciphers_valid(optarg)) { 504 /* SSH2 only */ 505 options.ciphers = xstrdup(optarg); 506 options.cipher = SSH_CIPHER_INVALID; 507 } else { 508 /* SSH1 only */ 509 options.cipher = cipher_number(optarg); 510 if (options.cipher == -1) { 511 fprintf(stderr, 512 "Unknown cipher type '%s'\n", 513 optarg); 514 exit(255); 515 } 516 if (options.cipher == SSH_CIPHER_3DES) 517 options.ciphers = "3des-cbc"; 518 else if (options.cipher == SSH_CIPHER_BLOWFISH) 519 options.ciphers = "blowfish-cbc"; 520 else 521 options.ciphers = (char *)-1; 522 } 523 break; 524 case 'm': 525 if (mac_valid(optarg)) 526 options.macs = xstrdup(optarg); 527 else { 528 fprintf(stderr, "Unknown mac type '%s'\n", 529 optarg); 530 exit(255); 531 } 532 break; 533 case 'M': 534 if (options.control_master == SSHCTL_MASTER_YES) 535 options.control_master = SSHCTL_MASTER_ASK; 536 else 537 options.control_master = SSHCTL_MASTER_YES; 538 break; 539 case 'p': 540 options.port = a2port(optarg); 541 if (options.port <= 0) { 542 fprintf(stderr, "Bad port '%s'\n", optarg); 543 exit(255); 544 } 545 break; 546 case 'l': 547 options.user = optarg; 548 break; 549 550 case 'L': 551 if (parse_forward(&fwd, optarg, 0, 0)) 552 add_local_forward(&options, &fwd); 553 else { 554 fprintf(stderr, 555 "Bad local forwarding specification '%s'\n", 556 optarg); 557 exit(255); 558 } 559 break; 560 561 case 'R': 562 if (parse_forward(&fwd, optarg, 0, 1)) { 563 add_remote_forward(&options, &fwd); 564 } else { 565 fprintf(stderr, 566 "Bad remote forwarding specification " 567 "'%s'\n", optarg); 568 exit(255); 569 } 570 break; 571 572 case 'D': 573 if (parse_forward(&fwd, optarg, 1, 0)) { 574 add_local_forward(&options, &fwd); 575 } else { 576 fprintf(stderr, 577 "Bad dynamic forwarding specification " 578 "'%s'\n", optarg); 579 exit(255); 580 } 581 break; 582 583 case 'C': 584 options.compression = 1; 585 break; 586 case 'N': 587 no_shell_flag = 1; 588 options.request_tty = REQUEST_TTY_NO; 589 break; 590 case 'T': 591 options.request_tty = REQUEST_TTY_NO; 592 #ifdef NONE_CIPHER_ENABLED 593 /* 594 * Ensure that the user does not try to backdoor a 595 * NONE cipher switch on an interactive session by 596 * explicitly disabling it if the user asks for a 597 * session without a tty. 598 */ 599 options.none_switch = 0; 600 #endif 601 break; 602 case 'o': 603 dummy = 1; 604 line = xstrdup(optarg); 605 if (process_config_line(&options, host ? host : "", 606 line, "command-line", 0, &dummy) != 0) 607 exit(255); 608 xfree(line); 609 break; 610 case 's': 611 subsystem_flag = 1; 612 break; 613 case 'S': 614 if (options.control_path != NULL) 615 free(options.control_path); 616 options.control_path = xstrdup(optarg); 617 break; 618 case 'b': 619 options.bind_address = optarg; 620 break; 621 case 'F': 622 config = optarg; 623 break; 624 default: 625 usage(); 626 } 627 } 628 629 ac -= optind; 630 av += optind; 631 632 if (ac > 0 && !host) { 633 if (strrchr(*av, '@')) { 634 p = xstrdup(*av); 635 cp = strrchr(p, '@'); 636 if (cp == NULL || cp == p) 637 usage(); 638 options.user = p; 639 *cp = '\0'; 640 host = ++cp; 641 } else 642 host = *av; 643 if (ac > 1) { 644 optind = optreset = 1; 645 goto again; 646 } 647 ac--, av++; 648 } 649 650 /* Check that we got a host name. */ 651 if (!host) 652 usage(); 653 654 OpenSSL_add_all_algorithms(); 655 ERR_load_crypto_strings(); 656 657 /* Initialize the command to execute on remote host. */ 658 buffer_init(&command); 659 660 /* 661 * Save the command to execute on the remote host in a buffer. There 662 * is no limit on the length of the command, except by the maximum 663 * packet size. Also sets the tty flag if there is no command. 664 */ 665 if (!ac) { 666 /* No command specified - execute shell on a tty. */ 667 if (subsystem_flag) { 668 fprintf(stderr, 669 "You must specify a subsystem to invoke.\n"); 670 usage(); 671 } 672 } else { 673 /* A command has been specified. Store it into the buffer. */ 674 for (i = 0; i < ac; i++) { 675 if (i) 676 buffer_append(&command, " ", 1); 677 buffer_append(&command, av[i], strlen(av[i])); 678 } 679 } 680 681 /* Cannot fork to background if no command. */ 682 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 683 !no_shell_flag) 684 fatal("Cannot fork into background without a command " 685 "to execute."); 686 687 /* 688 * Initialize "log" output. Since we are the client all output 689 * actually goes to stderr. 690 */ 691 log_init(argv0, 692 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 693 SYSLOG_FACILITY_USER, !use_syslog); 694 695 /* 696 * Read per-user configuration file. Ignore the system wide config 697 * file if the user specifies a config file on the command line. 698 */ 699 if (config != NULL) { 700 if (!read_config_file(config, host, &options, 0)) 701 fatal("Can't open user config file %.100s: " 702 "%.100s", config, strerror(errno)); 703 } else { 704 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, 705 _PATH_SSH_USER_CONFFILE); 706 if (r > 0 && (size_t)r < sizeof(buf)) 707 (void)read_config_file(buf, host, &options, 1); 708 709 /* Read systemwide configuration file after user config. */ 710 (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, 711 &options, 0); 712 } 713 714 /* Fill configuration defaults. */ 715 fill_default_options(&options); 716 717 channel_set_af(options.address_family); 718 719 /* reinit */ 720 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 721 722 if (options.request_tty == REQUEST_TTY_YES || 723 options.request_tty == REQUEST_TTY_FORCE) 724 tty_flag = 1; 725 726 /* Allocate a tty by default if no command specified. */ 727 if (buffer_len(&command) == 0) 728 tty_flag = options.request_tty != REQUEST_TTY_NO; 729 730 /* Force no tty */ 731 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0) 732 tty_flag = 0; 733 /* Do not allocate a tty if stdin is not a tty. */ 734 if ((!isatty(fileno(stdin)) || stdin_null_flag) && 735 options.request_tty != REQUEST_TTY_FORCE) { 736 if (tty_flag) 737 logit("Pseudo-terminal will not be allocated because " 738 "stdin is not a terminal."); 739 tty_flag = 0; 740 } 741 742 seed_rng(); 743 744 if (options.user == NULL) 745 options.user = xstrdup(pw->pw_name); 746 747 /* Get default port if port has not been set. */ 748 if (options.port == 0) { 749 sp = getservbyname(SSH_SERVICE_NAME, "tcp"); 750 options.port = sp ? ntohs(sp->s_port) : SSH_DEFAULT_PORT; 751 } 752 753 /* preserve host name given on command line for %n expansion */ 754 host_arg = host; 755 if (options.hostname != NULL) { 756 host = percent_expand(options.hostname, 757 "h", host, (char *)NULL); 758 } 759 760 if (gethostname(thishost, sizeof(thishost)) == -1) 761 fatal("gethostname: %s", strerror(errno)); 762 strlcpy(shorthost, thishost, sizeof(shorthost)); 763 shorthost[strcspn(thishost, ".")] = '\0'; 764 snprintf(portstr, sizeof(portstr), "%d", options.port); 765 766 if (options.local_command != NULL) { 767 debug3("expanding LocalCommand: %s", options.local_command); 768 cp = options.local_command; 769 options.local_command = percent_expand(cp, "d", pw->pw_dir, 770 "h", host, "l", thishost, "n", host_arg, "r", options.user, 771 "p", portstr, "u", pw->pw_name, "L", shorthost, 772 (char *)NULL); 773 debug3("expanded LocalCommand: %s", options.local_command); 774 xfree(cp); 775 } 776 777 /* Find canonic host name. */ 778 if (strchr(host, '.') == 0) { 779 struct addrinfo hints; 780 struct addrinfo *ai = NULL; 781 int errgai; 782 memset(&hints, 0, sizeof(hints)); 783 hints.ai_family = options.address_family; 784 hints.ai_flags = AI_CANONNAME; 785 hints.ai_socktype = SOCK_STREAM; 786 errgai = getaddrinfo(host, NULL, &hints, &ai); 787 if (errgai == 0) { 788 if (ai->ai_canonname != NULL) 789 host = xstrdup(ai->ai_canonname); 790 freeaddrinfo(ai); 791 } 792 } 793 794 /* force lowercase for hostkey matching */ 795 if (options.host_key_alias != NULL) { 796 for (p = options.host_key_alias; *p; p++) 797 if (isupper(*p)) 798 *p = (char)tolower(*p); 799 } 800 801 if (options.proxy_command != NULL && 802 strcmp(options.proxy_command, "none") == 0) { 803 xfree(options.proxy_command); 804 options.proxy_command = NULL; 805 } 806 if (options.control_path != NULL && 807 strcmp(options.control_path, "none") == 0) { 808 xfree(options.control_path); 809 options.control_path = NULL; 810 } 811 812 if (options.control_path != NULL) { 813 cp = tilde_expand_filename(options.control_path, 814 original_real_uid); 815 xfree(options.control_path); 816 options.control_path = percent_expand(cp, "h", host, 817 "l", thishost, "n", host_arg, "r", options.user, 818 "p", portstr, "u", pw->pw_name, "L", shorthost, 819 (char *)NULL); 820 xfree(cp); 821 } 822 if (muxclient_command != 0 && options.control_path == NULL) 823 fatal("No ControlPath specified for \"-O\" command"); 824 if (options.control_path != NULL) 825 muxclient(options.control_path); 826 827 timeout_ms = options.connection_timeout * 1000; 828 829 /* Open a connection to the remote host. */ 830 if (ssh_connect(host, &hostaddr, options.port, 831 options.address_family, options.connection_attempts, &timeout_ms, 832 options.tcp_keep_alive, 833 #ifdef HAVE_CYGWIN 834 options.use_privileged_port, 835 #else 836 original_effective_uid == 0 && options.use_privileged_port, 837 #endif 838 options.proxy_command) != 0) 839 exit(255); 840 841 if (timeout_ms > 0) 842 debug3("timeout: %d ms remain after connect", timeout_ms); 843 844 /* 845 * If we successfully made the connection, load the host private key 846 * in case we will need it later for combined rsa-rhosts 847 * authentication. This must be done before releasing extra 848 * privileges, because the file is only readable by root. 849 * If we cannot access the private keys, load the public keys 850 * instead and try to execute the ssh-keysign helper instead. 851 */ 852 sensitive_data.nkeys = 0; 853 sensitive_data.keys = NULL; 854 sensitive_data.external_keysign = 0; 855 if (options.rhosts_rsa_authentication || 856 options.hostbased_authentication) { 857 sensitive_data.nkeys = 7; 858 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 859 sizeof(Key)); 860 for (i = 0; i < sensitive_data.nkeys; i++) 861 sensitive_data.keys[i] = NULL; 862 863 PRIV_START; 864 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 865 _PATH_HOST_KEY_FILE, "", NULL, NULL); 866 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA, 867 _PATH_HOST_DSA_KEY_FILE, "", NULL); 868 #ifdef OPENSSL_HAS_ECC 869 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA, 870 _PATH_HOST_ECDSA_KEY_FILE, "", NULL); 871 #endif 872 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA, 873 _PATH_HOST_RSA_KEY_FILE, "", NULL); 874 sensitive_data.keys[4] = key_load_private_type(KEY_DSA, 875 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 876 #ifdef OPENSSL_HAS_ECC 877 sensitive_data.keys[5] = key_load_private_type(KEY_ECDSA, 878 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL); 879 #endif 880 sensitive_data.keys[6] = key_load_private_type(KEY_RSA, 881 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 882 PRIV_END; 883 884 if (options.hostbased_authentication == 1 && 885 sensitive_data.keys[0] == NULL && 886 sensitive_data.keys[4] == NULL && 887 sensitive_data.keys[5] == NULL && 888 sensitive_data.keys[6] == NULL) { 889 sensitive_data.keys[1] = key_load_cert( 890 _PATH_HOST_DSA_KEY_FILE); 891 #ifdef OPENSSL_HAS_ECC 892 sensitive_data.keys[2] = key_load_cert( 893 _PATH_HOST_ECDSA_KEY_FILE); 894 #endif 895 sensitive_data.keys[3] = key_load_cert( 896 _PATH_HOST_RSA_KEY_FILE); 897 sensitive_data.keys[4] = key_load_public( 898 _PATH_HOST_DSA_KEY_FILE, NULL); 899 #ifdef OPENSSL_HAS_ECC 900 sensitive_data.keys[5] = key_load_public( 901 _PATH_HOST_ECDSA_KEY_FILE, NULL); 902 #endif 903 sensitive_data.keys[6] = key_load_public( 904 _PATH_HOST_RSA_KEY_FILE, NULL); 905 sensitive_data.external_keysign = 1; 906 } 907 } 908 /* 909 * Get rid of any extra privileges that we may have. We will no 910 * longer need them. Also, extra privileges could make it very hard 911 * to read identity files and other non-world-readable files from the 912 * user's home directory if it happens to be on a NFS volume where 913 * root is mapped to nobody. 914 */ 915 if (original_effective_uid == 0) { 916 PRIV_START; 917 permanently_set_uid(pw); 918 } 919 920 /* 921 * Now that we are back to our own permissions, create ~/.ssh 922 * directory if it doesn't already exist. 923 */ 924 if (config == NULL) { 925 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 926 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 927 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) { 928 #ifdef WITH_SELINUX 929 ssh_selinux_setfscreatecon(buf); 930 #endif 931 if (mkdir(buf, 0700) < 0) 932 error("Could not create directory '%.200s'.", 933 buf); 934 #ifdef WITH_SELINUX 935 ssh_selinux_setfscreatecon(NULL); 936 #endif 937 } 938 } 939 /* load options.identity_files */ 940 load_public_identity_files(); 941 942 /* Expand ~ in known host file names. */ 943 tilde_expand_paths(options.system_hostfiles, 944 options.num_system_hostfiles); 945 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles); 946 947 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 948 signal(SIGCHLD, main_sigchld_handler); 949 950 /* Log into the remote system. Never returns if the login fails. */ 951 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 952 options.port, pw, timeout_ms); 953 954 if (packet_connection_is_on_socket()) { 955 verbose("Authenticated to %s ([%s]:%d).", host, 956 get_remote_ipaddr(), get_remote_port()); 957 } else { 958 verbose("Authenticated to %s (via proxy).", host); 959 } 960 961 /* We no longer need the private host keys. Clear them now. */ 962 if (sensitive_data.nkeys != 0) { 963 for (i = 0; i < sensitive_data.nkeys; i++) { 964 if (sensitive_data.keys[i] != NULL) { 965 /* Destroys contents safely */ 966 debug3("clear hostkey %d", i); 967 key_free(sensitive_data.keys[i]); 968 sensitive_data.keys[i] = NULL; 969 } 970 } 971 xfree(sensitive_data.keys); 972 } 973 for (i = 0; i < options.num_identity_files; i++) { 974 if (options.identity_files[i]) { 975 xfree(options.identity_files[i]); 976 options.identity_files[i] = NULL; 977 } 978 if (options.identity_keys[i]) { 979 key_free(options.identity_keys[i]); 980 options.identity_keys[i] = NULL; 981 } 982 } 983 984 exit_status = compat20 ? ssh_session2() : ssh_session(); 985 packet_close(); 986 987 if (options.control_path != NULL && muxserver_sock != -1) 988 unlink(options.control_path); 989 990 /* Kill ProxyCommand if it is running. */ 991 ssh_kill_proxy_command(); 992 993 return exit_status; 994 } 995 996 static void 997 control_persist_detach(void) 998 { 999 pid_t pid; 1000 int devnull; 1001 1002 debug("%s: backgrounding master process", __func__); 1003 1004 /* 1005 * master (current process) into the background, and make the 1006 * foreground process a client of the backgrounded master. 1007 */ 1008 switch ((pid = fork())) { 1009 case -1: 1010 fatal("%s: fork: %s", __func__, strerror(errno)); 1011 case 0: 1012 /* Child: master process continues mainloop */ 1013 break; 1014 default: 1015 /* Parent: set up mux slave to connect to backgrounded master */ 1016 debug2("%s: background process is %ld", __func__, (long)pid); 1017 stdin_null_flag = ostdin_null_flag; 1018 options.request_tty = orequest_tty; 1019 tty_flag = otty_flag; 1020 close(muxserver_sock); 1021 muxserver_sock = -1; 1022 options.control_master = SSHCTL_MASTER_NO; 1023 muxclient(options.control_path); 1024 /* muxclient() doesn't return on success. */ 1025 fatal("Failed to connect to new control master"); 1026 } 1027 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { 1028 error("%s: open(\"/dev/null\"): %s", __func__, 1029 strerror(errno)); 1030 } else { 1031 if (dup2(devnull, STDIN_FILENO) == -1 || 1032 dup2(devnull, STDOUT_FILENO) == -1) 1033 error("%s: dup2: %s", __func__, strerror(errno)); 1034 if (devnull > STDERR_FILENO) 1035 close(devnull); 1036 } 1037 setproctitle("%s [mux]", options.control_path); 1038 } 1039 1040 /* Do fork() after authentication. Used by "ssh -f" */ 1041 static void 1042 fork_postauth(void) 1043 { 1044 if (need_controlpersist_detach) 1045 control_persist_detach(); 1046 debug("forking to background"); 1047 fork_after_authentication_flag = 0; 1048 if (daemon(1, 1) < 0) 1049 fatal("daemon() failed: %.200s", strerror(errno)); 1050 } 1051 1052 /* Callback for remote forward global requests */ 1053 static void 1054 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 1055 { 1056 Forward *rfwd = (Forward *)ctxt; 1057 1058 /* XXX verbose() on failure? */ 1059 debug("remote forward %s for: listen %d, connect %s:%d", 1060 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 1061 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 1062 if (rfwd->listen_port == 0) { 1063 if (type == SSH2_MSG_REQUEST_SUCCESS) { 1064 rfwd->allocated_port = packet_get_int(); 1065 logit("Allocated port %u for remote forward to %s:%d", 1066 rfwd->allocated_port, 1067 rfwd->connect_host, rfwd->connect_port); 1068 channel_update_permitted_opens(rfwd->handle, 1069 rfwd->allocated_port); 1070 } else { 1071 channel_update_permitted_opens(rfwd->handle, -1); 1072 } 1073 } 1074 1075 if (type == SSH2_MSG_REQUEST_FAILURE) { 1076 if (options.exit_on_forward_failure) 1077 fatal("Error: remote port forwarding failed for " 1078 "listen port %d", rfwd->listen_port); 1079 else 1080 logit("Warning: remote port forwarding failed for " 1081 "listen port %d", rfwd->listen_port); 1082 } 1083 if (++remote_forward_confirms_received == options.num_remote_forwards) { 1084 debug("All remote forwarding requests processed"); 1085 if (fork_after_authentication_flag) 1086 fork_postauth(); 1087 } 1088 } 1089 1090 static void 1091 client_cleanup_stdio_fwd(int id, void *arg) 1092 { 1093 debug("stdio forwarding: done"); 1094 cleanup_exit(0); 1095 } 1096 1097 static void 1098 ssh_init_stdio_forwarding(void) 1099 { 1100 Channel *c; 1101 int in, out; 1102 1103 if (stdio_forward_host == NULL) 1104 return; 1105 if (!compat20) 1106 fatal("stdio forwarding require Protocol 2"); 1107 1108 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port); 1109 1110 if ((in = dup(STDIN_FILENO)) < 0 || 1111 (out = dup(STDOUT_FILENO)) < 0) 1112 fatal("channel_connect_stdio_fwd: dup() in/out failed"); 1113 if ((c = channel_connect_stdio_fwd(stdio_forward_host, 1114 stdio_forward_port, in, out)) == NULL) 1115 fatal("%s: channel_connect_stdio_fwd failed", __func__); 1116 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0); 1117 } 1118 1119 static void 1120 ssh_init_forwarding(void) 1121 { 1122 int success = 0; 1123 int i; 1124 1125 /* Initiate local TCP/IP port forwardings. */ 1126 for (i = 0; i < options.num_local_forwards; i++) { 1127 debug("Local connections to %.200s:%d forwarded to remote " 1128 "address %.200s:%d", 1129 (options.local_forwards[i].listen_host == NULL) ? 1130 (options.gateway_ports ? "*" : "LOCALHOST") : 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 success += channel_setup_local_fwd_listener( 1136 options.local_forwards[i].listen_host, 1137 options.local_forwards[i].listen_port, 1138 options.local_forwards[i].connect_host, 1139 options.local_forwards[i].connect_port, 1140 options.gateway_ports); 1141 } 1142 if (i > 0 && success != i && options.exit_on_forward_failure) 1143 fatal("Could not request local forwarding."); 1144 if (i > 0 && success == 0) 1145 error("Could not request local forwarding."); 1146 1147 /* Initiate remote TCP/IP port forwardings. */ 1148 for (i = 0; i < options.num_remote_forwards; i++) { 1149 debug("Remote connections from %.200s:%d forwarded to " 1150 "local address %.200s:%d", 1151 (options.remote_forwards[i].listen_host == NULL) ? 1152 "LOCALHOST" : options.remote_forwards[i].listen_host, 1153 options.remote_forwards[i].listen_port, 1154 options.remote_forwards[i].connect_host, 1155 options.remote_forwards[i].connect_port); 1156 options.remote_forwards[i].handle = 1157 channel_request_remote_forwarding( 1158 options.remote_forwards[i].listen_host, 1159 options.remote_forwards[i].listen_port, 1160 options.remote_forwards[i].connect_host, 1161 options.remote_forwards[i].connect_port); 1162 if (options.remote_forwards[i].handle < 0) { 1163 if (options.exit_on_forward_failure) 1164 fatal("Could not request remote forwarding."); 1165 else 1166 logit("Warning: Could not request remote " 1167 "forwarding."); 1168 } else { 1169 client_register_global_confirm(ssh_confirm_remote_forward, 1170 &options.remote_forwards[i]); 1171 } 1172 } 1173 1174 /* Initiate tunnel forwarding. */ 1175 if (options.tun_open != SSH_TUNMODE_NO) { 1176 if (client_request_tun_fwd(options.tun_open, 1177 options.tun_local, options.tun_remote) == -1) { 1178 if (options.exit_on_forward_failure) 1179 fatal("Could not request tunnel forwarding."); 1180 else 1181 error("Could not request tunnel forwarding."); 1182 } 1183 } 1184 } 1185 1186 static void 1187 check_agent_present(void) 1188 { 1189 if (options.forward_agent) { 1190 /* Clear agent forwarding if we don't have an agent. */ 1191 if (!ssh_agent_present()) 1192 options.forward_agent = 0; 1193 } 1194 } 1195 1196 static int 1197 ssh_session(void) 1198 { 1199 int type; 1200 int interactive = 0; 1201 int have_tty = 0; 1202 struct winsize ws; 1203 char *cp; 1204 const char *display; 1205 1206 /* Enable compression if requested. */ 1207 if (options.compression) { 1208 debug("Requesting compression at level %d.", 1209 options.compression_level); 1210 1211 if (options.compression_level < 1 || 1212 options.compression_level > 9) 1213 fatal("Compression level must be from 1 (fast) to " 1214 "9 (slow, best)."); 1215 1216 /* Send the request. */ 1217 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 1218 packet_put_int(options.compression_level); 1219 packet_send(); 1220 packet_write_wait(); 1221 type = packet_read(); 1222 if (type == SSH_SMSG_SUCCESS) 1223 packet_start_compression(options.compression_level); 1224 else if (type == SSH_SMSG_FAILURE) 1225 logit("Warning: Remote host refused compression."); 1226 else 1227 packet_disconnect("Protocol error waiting for " 1228 "compression response."); 1229 } 1230 /* Allocate a pseudo tty if appropriate. */ 1231 if (tty_flag) { 1232 debug("Requesting pty."); 1233 1234 /* Start the packet. */ 1235 packet_start(SSH_CMSG_REQUEST_PTY); 1236 1237 /* Store TERM in the packet. There is no limit on the 1238 length of the string. */ 1239 cp = getenv("TERM"); 1240 if (!cp) 1241 cp = ""; 1242 packet_put_cstring(cp); 1243 1244 /* Store window size in the packet. */ 1245 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1246 memset(&ws, 0, sizeof(ws)); 1247 packet_put_int((u_int)ws.ws_row); 1248 packet_put_int((u_int)ws.ws_col); 1249 packet_put_int((u_int)ws.ws_xpixel); 1250 packet_put_int((u_int)ws.ws_ypixel); 1251 1252 /* Store tty modes in the packet. */ 1253 tty_make_modes(fileno(stdin), NULL); 1254 1255 /* Send the packet, and wait for it to leave. */ 1256 packet_send(); 1257 packet_write_wait(); 1258 1259 /* Read response from the server. */ 1260 type = packet_read(); 1261 if (type == SSH_SMSG_SUCCESS) { 1262 interactive = 1; 1263 have_tty = 1; 1264 } else if (type == SSH_SMSG_FAILURE) 1265 logit("Warning: Remote host failed or refused to " 1266 "allocate a pseudo tty."); 1267 else 1268 packet_disconnect("Protocol error waiting for pty " 1269 "request response."); 1270 } 1271 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1272 display = getenv("DISPLAY"); 1273 if (options.forward_x11 && display != NULL) { 1274 char *proto, *data; 1275 /* Get reasonable local authentication information. */ 1276 client_x11_get_proto(display, options.xauth_location, 1277 options.forward_x11_trusted, 1278 options.forward_x11_timeout, 1279 &proto, &data); 1280 /* Request forwarding with authentication spoofing. */ 1281 debug("Requesting X11 forwarding with authentication " 1282 "spoofing."); 1283 x11_request_forwarding_with_spoofing(0, display, proto, 1284 data, 0); 1285 /* Read response from the server. */ 1286 type = packet_read(); 1287 if (type == SSH_SMSG_SUCCESS) { 1288 interactive = 1; 1289 } else if (type == SSH_SMSG_FAILURE) { 1290 logit("Warning: Remote host denied X11 forwarding."); 1291 } else { 1292 packet_disconnect("Protocol error waiting for X11 " 1293 "forwarding"); 1294 } 1295 } 1296 /* Tell the packet module whether this is an interactive session. */ 1297 packet_set_interactive(interactive, 1298 options.ip_qos_interactive, options.ip_qos_bulk); 1299 1300 /* Request authentication agent forwarding if appropriate. */ 1301 check_agent_present(); 1302 1303 if (options.forward_agent) { 1304 debug("Requesting authentication agent forwarding."); 1305 auth_request_forwarding(); 1306 1307 /* Read response from the server. */ 1308 type = packet_read(); 1309 packet_check_eom(); 1310 if (type != SSH_SMSG_SUCCESS) 1311 logit("Warning: Remote host denied authentication agent forwarding."); 1312 } 1313 1314 /* Initiate port forwardings. */ 1315 ssh_init_stdio_forwarding(); 1316 ssh_init_forwarding(); 1317 1318 /* Execute a local command */ 1319 if (options.local_command != NULL && 1320 options.permit_local_command) 1321 ssh_local_cmd(options.local_command); 1322 1323 /* 1324 * If requested and we are not interested in replies to remote 1325 * forwarding requests, then let ssh continue in the background. 1326 */ 1327 if (fork_after_authentication_flag) { 1328 if (options.exit_on_forward_failure && 1329 options.num_remote_forwards > 0) { 1330 debug("deferring postauth fork until remote forward " 1331 "confirmation received"); 1332 } else 1333 fork_postauth(); 1334 } 1335 1336 /* 1337 * If a command was specified on the command line, execute the 1338 * command now. Otherwise request the server to start a shell. 1339 */ 1340 if (buffer_len(&command) > 0) { 1341 int len = buffer_len(&command); 1342 if (len > 900) 1343 len = 900; 1344 debug("Sending command: %.*s", len, 1345 (u_char *)buffer_ptr(&command)); 1346 packet_start(SSH_CMSG_EXEC_CMD); 1347 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1348 packet_send(); 1349 packet_write_wait(); 1350 } else { 1351 debug("Requesting shell."); 1352 packet_start(SSH_CMSG_EXEC_SHELL); 1353 packet_send(); 1354 packet_write_wait(); 1355 } 1356 1357 /* Enter the interactive session. */ 1358 return client_loop(have_tty, tty_flag ? 1359 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1360 } 1361 1362 /* request pty/x11/agent/tcpfwd/shell for channel */ 1363 static void 1364 ssh_session2_setup(int id, int success, void *arg) 1365 { 1366 extern char **environ; 1367 const char *display; 1368 int interactive = tty_flag; 1369 1370 if (!success) 1371 return; /* No need for error message, channels code sens one */ 1372 1373 display = getenv("DISPLAY"); 1374 if (options.forward_x11 && display != NULL) { 1375 char *proto, *data; 1376 /* Get reasonable local authentication information. */ 1377 client_x11_get_proto(display, options.xauth_location, 1378 options.forward_x11_trusted, 1379 options.forward_x11_timeout, &proto, &data); 1380 /* Request forwarding with authentication spoofing. */ 1381 debug("Requesting X11 forwarding with authentication " 1382 "spoofing."); 1383 x11_request_forwarding_with_spoofing(id, display, proto, 1384 data, 1); 1385 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); 1386 /* XXX exit_on_forward_failure */ 1387 interactive = 1; 1388 } 1389 1390 check_agent_present(); 1391 if (options.forward_agent) { 1392 debug("Requesting authentication agent forwarding."); 1393 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1394 packet_send(); 1395 } 1396 1397 /* Tell the packet module whether this is an interactive session. */ 1398 packet_set_interactive(interactive, 1399 options.ip_qos_interactive, options.ip_qos_bulk); 1400 1401 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1402 NULL, fileno(stdin), &command, environ); 1403 } 1404 1405 /* open new channel for a session */ 1406 static int 1407 ssh_session2_open(void) 1408 { 1409 Channel *c; 1410 int window, packetmax, in, out, err; 1411 1412 if (stdin_null_flag) { 1413 in = open(_PATH_DEVNULL, O_RDONLY); 1414 } else { 1415 in = dup(STDIN_FILENO); 1416 } 1417 out = dup(STDOUT_FILENO); 1418 err = dup(STDERR_FILENO); 1419 1420 if (in < 0 || out < 0 || err < 0) 1421 fatal("dup() in/out/err failed"); 1422 1423 /* enable nonblocking unless tty */ 1424 if (!isatty(in)) 1425 set_nonblock(in); 1426 if (!isatty(out)) 1427 set_nonblock(out); 1428 if (!isatty(err)) 1429 set_nonblock(err); 1430 1431 /* 1432 * We need to check to see what to do about buffer sizes here. 1433 * - In an HPN to non-HPN connection we want to limit the window size to 1434 * something reasonable in case the far side has the large window bug. 1435 * - In an HPN to HPN connection we want to use the max window size but 1436 * allow the user to override it. 1437 * - Lastly if HPN is disabled then use the ssh standard window size. 1438 * 1439 * We cannot just do a getsockopt() here and set the ssh window to that 1440 * as in case of autotuning of socket buffers the window would get stuck 1441 * at the initial buffer size, generally less than 96k. Therefore we 1442 * need to set the maximum ssh window size to the maximum HPN buffer 1443 * size unless the user has set TcpRcvBufPoll to no. In that case we 1444 * can just set the window to the minimum of HPN buffer size and TCP 1445 * receive buffer size. 1446 */ 1447 if (tty_flag) 1448 options.hpn_buffer_size = CHAN_SES_WINDOW_DEFAULT; 1449 else 1450 options.hpn_buffer_size = CHAN_HPN_MIN_WINDOW_DEFAULT; 1451 1452 if (datafellows & SSH_BUG_LARGEWINDOW) { 1453 debug("HPN to Non-HPN Connection"); 1454 } else if (options.tcp_rcv_buf_poll <= 0) { 1455 sock_get_rcvbuf(&options.hpn_buffer_size, 0); 1456 debug("HPNBufferSize set to TCP RWIN: %d", 1457 options.hpn_buffer_size); 1458 } else if (options.tcp_rcv_buf > 0) { 1459 sock_get_rcvbuf(&options.hpn_buffer_size, 1460 options.tcp_rcv_buf); 1461 debug("HPNBufferSize set to user TCPRcvBuf: %d", 1462 options.hpn_buffer_size); 1463 } 1464 debug("Final hpn_buffer_size = %d", options.hpn_buffer_size); 1465 channel_set_hpn(options.hpn_disabled, options.hpn_buffer_size); 1466 window = options.hpn_buffer_size; 1467 1468 packetmax = CHAN_SES_PACKET_DEFAULT; 1469 if (tty_flag) { 1470 window = CHAN_SES_WINDOW_DEFAULT; 1471 window >>= 1; 1472 packetmax >>= 1; 1473 } 1474 c = channel_new( 1475 "session", SSH_CHANNEL_OPENING, in, out, err, 1476 window, packetmax, CHAN_EXTENDED_WRITE, 1477 "client-session", /*nonblock*/0); 1478 if (!options.hpn_disabled && options.tcp_rcv_buf_poll > 0) { 1479 c->dynamic_window = 1; 1480 debug("Enabled Dynamic Window Scaling\n"); 1481 } 1482 1483 debug3("ssh_session2_open: channel_new: %d", c->self); 1484 1485 channel_send_open(c->self); 1486 if (!no_shell_flag) 1487 channel_register_open_confirm(c->self, 1488 ssh_session2_setup, NULL); 1489 1490 return c->self; 1491 } 1492 1493 static int 1494 ssh_session2(void) 1495 { 1496 int id = -1; 1497 1498 /* XXX should be pre-session */ 1499 if (!options.control_persist) 1500 ssh_init_stdio_forwarding(); 1501 ssh_init_forwarding(); 1502 1503 /* Start listening for multiplex clients */ 1504 muxserver_listen(); 1505 1506 /* 1507 * If we are in control persist mode and have a working mux listen 1508 * socket, then prepare to background ourselves and have a foreground 1509 * client attach as a control slave. 1510 * NB. we must save copies of the flags that we override for 1511 * the backgrounding, since we defer attachment of the slave until 1512 * after the connection is fully established (in particular, 1513 * async rfwd replies have been received for ExitOnForwardFailure). 1514 */ 1515 if (options.control_persist && muxserver_sock != -1) { 1516 ostdin_null_flag = stdin_null_flag; 1517 ono_shell_flag = no_shell_flag; 1518 orequest_tty = options.request_tty; 1519 otty_flag = tty_flag; 1520 stdin_null_flag = 1; 1521 no_shell_flag = 1; 1522 tty_flag = 0; 1523 if (!fork_after_authentication_flag) 1524 need_controlpersist_detach = 1; 1525 fork_after_authentication_flag = 1; 1526 } 1527 /* 1528 * ControlPersist mux listen socket setup failed, attempt the 1529 * stdio forward setup that we skipped earlier. 1530 */ 1531 if (options.control_persist && muxserver_sock == -1) 1532 ssh_init_stdio_forwarding(); 1533 1534 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1535 id = ssh_session2_open(); 1536 1537 /* If we don't expect to open a new session, then disallow it */ 1538 if (options.control_master == SSHCTL_MASTER_NO && 1539 (datafellows & SSH_NEW_OPENSSH)) { 1540 debug("Requesting no-more-sessions@openssh.com"); 1541 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1542 packet_put_cstring("no-more-sessions@openssh.com"); 1543 packet_put_char(0); 1544 packet_send(); 1545 } 1546 1547 /* Execute a local command */ 1548 if (options.local_command != NULL && 1549 options.permit_local_command) 1550 ssh_local_cmd(options.local_command); 1551 1552 /* 1553 * If requested and we are not interested in replies to remote 1554 * forwarding requests, then let ssh continue in the background. 1555 */ 1556 if (fork_after_authentication_flag) { 1557 if (options.exit_on_forward_failure && 1558 options.num_remote_forwards > 0) { 1559 debug("deferring postauth fork until remote forward " 1560 "confirmation received"); 1561 } else 1562 fork_postauth(); 1563 } 1564 1565 if (options.use_roaming) 1566 request_roaming(); 1567 1568 return client_loop(tty_flag, tty_flag ? 1569 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1570 } 1571 1572 static void 1573 load_public_identity_files(void) 1574 { 1575 char *filename, *cp, thishost[NI_MAXHOST]; 1576 char *pwdir = NULL, *pwname = NULL; 1577 int i = 0; 1578 Key *public; 1579 struct passwd *pw; 1580 u_int n_ids; 1581 char *identity_files[SSH_MAX_IDENTITY_FILES]; 1582 Key *identity_keys[SSH_MAX_IDENTITY_FILES]; 1583 #ifdef ENABLE_PKCS11 1584 Key **keys; 1585 int nkeys; 1586 #endif /* PKCS11 */ 1587 1588 n_ids = 0; 1589 bzero(identity_files, sizeof(identity_files)); 1590 bzero(identity_keys, sizeof(identity_keys)); 1591 1592 #ifdef ENABLE_PKCS11 1593 if (options.pkcs11_provider != NULL && 1594 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1595 (pkcs11_init(!options.batch_mode) == 0) && 1596 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL, 1597 &keys)) > 0) { 1598 for (i = 0; i < nkeys; i++) { 1599 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1600 key_free(keys[i]); 1601 continue; 1602 } 1603 identity_keys[n_ids] = keys[i]; 1604 identity_files[n_ids] = 1605 xstrdup(options.pkcs11_provider); /* XXX */ 1606 n_ids++; 1607 } 1608 xfree(keys); 1609 } 1610 #endif /* ENABLE_PKCS11 */ 1611 if ((pw = getpwuid(original_real_uid)) == NULL) 1612 fatal("load_public_identity_files: getpwuid failed"); 1613 pwname = xstrdup(pw->pw_name); 1614 pwdir = xstrdup(pw->pw_dir); 1615 if (gethostname(thishost, sizeof(thishost)) == -1) 1616 fatal("load_public_identity_files: gethostname: %s", 1617 strerror(errno)); 1618 for (i = 0; i < options.num_identity_files; i++) { 1619 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1620 xfree(options.identity_files[i]); 1621 continue; 1622 } 1623 cp = tilde_expand_filename(options.identity_files[i], 1624 original_real_uid); 1625 filename = percent_expand(cp, "d", pwdir, 1626 "u", pwname, "l", thishost, "h", host, 1627 "r", options.user, (char *)NULL); 1628 xfree(cp); 1629 public = key_load_public(filename, NULL); 1630 debug("identity file %s type %d", filename, 1631 public ? public->type : -1); 1632 xfree(options.identity_files[i]); 1633 identity_files[n_ids] = filename; 1634 identity_keys[n_ids] = public; 1635 1636 if (++n_ids >= SSH_MAX_IDENTITY_FILES) 1637 continue; 1638 1639 /* Try to add the certificate variant too */ 1640 xasprintf(&cp, "%s-cert", filename); 1641 public = key_load_public(cp, NULL); 1642 debug("identity file %s type %d", cp, 1643 public ? public->type : -1); 1644 if (public == NULL) { 1645 xfree(cp); 1646 continue; 1647 } 1648 if (!key_is_cert(public)) { 1649 debug("%s: key %s type %s is not a certificate", 1650 __func__, cp, key_type(public)); 1651 key_free(public); 1652 xfree(cp); 1653 continue; 1654 } 1655 identity_keys[n_ids] = public; 1656 /* point to the original path, most likely the private key */ 1657 identity_files[n_ids] = xstrdup(filename); 1658 n_ids++; 1659 } 1660 options.num_identity_files = n_ids; 1661 memcpy(options.identity_files, identity_files, sizeof(identity_files)); 1662 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys)); 1663 1664 bzero(pwname, strlen(pwname)); 1665 xfree(pwname); 1666 bzero(pwdir, strlen(pwdir)); 1667 xfree(pwdir); 1668 } 1669 1670 static void 1671 main_sigchld_handler(int sig) 1672 { 1673 int save_errno = errno; 1674 pid_t pid; 1675 int status; 1676 1677 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 1678 (pid < 0 && errno == EINTR)) 1679 ; 1680 1681 signal(sig, main_sigchld_handler); 1682 errno = save_errno; 1683 } 1684 1685