ssh.c revision 294693
1/* $OpenBSD: ssh.c,v 1.401 2014/02/26 20:18:37 djm Exp $ */ 2/* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * Ssh client program. This program can be used to log into a remote machine. 7 * The software supports strong authentication, encryption, and forwarding 8 * of X11, TCP/IP, and authentication connections. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * Copyright (c) 1999 Niels Provos. All rights reserved. 17 * Copyright (c) 2000, 2001, 2002, 2003 Markus Friedl. All rights reserved. 18 * 19 * Modified to work with SSL by Niels Provos <provos@citi.umich.edu> 20 * in Canada (German citizen). 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 32 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 34 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 41 */ 42 43#include "includes.h" 44__RCSID("$FreeBSD: stable/10/crypto/openssh/ssh.c 294693 2016-01-24 22:28:18Z des $"); 45 46#include <sys/types.h> 47#ifdef HAVE_SYS_STAT_H 48# include <sys/stat.h> 49#endif 50#include <sys/resource.h> 51#include <sys/ioctl.h> 52#include <sys/param.h> 53#include <sys/socket.h> 54#include <sys/wait.h> 55 56#include <ctype.h> 57#include <errno.h> 58#include <fcntl.h> 59#include <netdb.h> 60#ifdef HAVE_PATHS_H 61#include <paths.h> 62#endif 63#include <pwd.h> 64#include <signal.h> 65#include <stdarg.h> 66#include <stddef.h> 67#include <stdio.h> 68#include <stdlib.h> 69#include <string.h> 70#include <unistd.h> 71 72#include <netinet/in.h> 73#include <arpa/inet.h> 74 75#include <openssl/evp.h> 76#include <openssl/err.h> 77#include "openbsd-compat/openssl-compat.h" 78#include "openbsd-compat/sys-queue.h" 79 80#include "xmalloc.h" 81#include "ssh.h" 82#include "ssh1.h" 83#include "ssh2.h" 84#include "canohost.h" 85#include "compat.h" 86#include "cipher.h" 87#include "packet.h" 88#include "buffer.h" 89#include "channels.h" 90#include "key.h" 91#include "authfd.h" 92#include "authfile.h" 93#include "pathnames.h" 94#include "dispatch.h" 95#include "clientloop.h" 96#include "log.h" 97#include "readconf.h" 98#include "sshconnect.h" 99#include "misc.h" 100#include "kex.h" 101#include "mac.h" 102#include "sshpty.h" 103#include "match.h" 104#include "msg.h" 105#include "uidswap.h" 106#include "roaming.h" 107#include "version.h" 108 109#ifdef ENABLE_PKCS11 110#include "ssh-pkcs11.h" 111#endif 112 113extern char *__progname; 114 115/* Saves a copy of argv for setproctitle emulation */ 116#ifndef HAVE_SETPROCTITLE 117static char **saved_av; 118#endif 119 120/* Flag indicating whether debug mode is on. May be set on the command line. */ 121int debug_flag = 0; 122 123/* Flag indicating whether a tty should be requested */ 124int tty_flag = 0; 125 126/* don't exec a shell */ 127int no_shell_flag = 0; 128 129/* 130 * Flag indicating that nothing should be read from stdin. This can be set 131 * on the command line. 132 */ 133int stdin_null_flag = 0; 134 135/* 136 * Flag indicating that the current process should be backgrounded and 137 * a new slave launched in the foreground for ControlPersist. 138 */ 139int need_controlpersist_detach = 0; 140 141/* Copies of flags for ControlPersist foreground slave */ 142int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty; 143 144/* 145 * Flag indicating that ssh should fork after authentication. This is useful 146 * so that the passphrase can be entered manually, and then ssh goes to the 147 * background. 148 */ 149int fork_after_authentication_flag = 0; 150 151/* forward stdio to remote host and port */ 152char *stdio_forward_host = NULL; 153int stdio_forward_port = 0; 154 155/* 156 * General data structure for command line options and options configurable 157 * in configuration files. See readconf.h. 158 */ 159Options options; 160 161/* optional user configfile */ 162char *config = NULL; 163 164/* 165 * Name of the host we are connecting to. This is the name given on the 166 * command line, or the HostName specified for the user-supplied name in a 167 * configuration file. 168 */ 169char *host; 170 171/* socket address the host resolves to */ 172struct sockaddr_storage hostaddr; 173 174/* Private host keys. */ 175Sensitive sensitive_data; 176 177/* Original real UID. */ 178uid_t original_real_uid; 179uid_t original_effective_uid; 180 181/* command to be executed */ 182Buffer command; 183 184/* Should we execute a command or invoke a subsystem? */ 185int subsystem_flag = 0; 186 187/* # of replies received for global requests */ 188static int remote_forward_confirms_received = 0; 189 190/* mux.c */ 191extern int muxserver_sock; 192extern u_int muxclient_command; 193 194/* Prints a help message to the user. This function never returns. */ 195 196static void 197usage(void) 198{ 199 fprintf(stderr, 200"usage: ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" 201" [-D [bind_address:]port] [-E log_file] [-e escape_char]\n" 202" [-F configfile] [-I pkcs11] [-i identity_file]\n" 203" [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec]\n" 204" [-O ctl_cmd] [-o option] [-p port]\n" 205" [-Q cipher | cipher-auth | mac | kex | key]\n" 206" [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port]\n" 207" [-w local_tun[:remote_tun]] [user@]hostname [command]\n" 208 ); 209 exit(255); 210} 211 212static int ssh_session(void); 213static int ssh_session2(void); 214static void load_public_identity_files(void); 215static void main_sigchld_handler(int); 216 217/* from muxclient.c */ 218void muxclient(const char *); 219void muxserver_listen(void); 220 221/* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */ 222static void 223tilde_expand_paths(char **paths, u_int num_paths) 224{ 225 u_int i; 226 char *cp; 227 228 for (i = 0; i < num_paths; i++) { 229 cp = tilde_expand_filename(paths[i], original_real_uid); 230 free(paths[i]); 231 paths[i] = cp; 232 } 233} 234 235/* 236 * Attempt to resolve a host name / port to a set of addresses and 237 * optionally return any CNAMEs encountered along the way. 238 * Returns NULL on failure. 239 * NB. this function must operate with a options having undefined members. 240 */ 241static struct addrinfo * 242resolve_host(const char *name, int port, int logerr, char *cname, size_t clen) 243{ 244 char strport[NI_MAXSERV]; 245 struct addrinfo hints, *res; 246 int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1; 247 248 if (port <= 0) 249 port = default_ssh_port(); 250 251 snprintf(strport, sizeof strport, "%u", port); 252 memset(&hints, 0, sizeof(hints)); 253 hints.ai_family = options.address_family == -1 ? 254 AF_UNSPEC : options.address_family; 255 hints.ai_socktype = SOCK_STREAM; 256 if (cname != NULL) 257 hints.ai_flags = AI_CANONNAME; 258 if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) { 259 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA)) 260 loglevel = SYSLOG_LEVEL_ERROR; 261 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s", 262 __progname, name, ssh_gai_strerror(gaierr)); 263 return NULL; 264 } 265 if (cname != NULL && res->ai_canonname != NULL) { 266 if (strlcpy(cname, res->ai_canonname, clen) >= clen) { 267 error("%s: host \"%s\" cname \"%s\" too long (max %lu)", 268 __func__, name, res->ai_canonname, (u_long)clen); 269 if (clen > 0) 270 *cname = '\0'; 271 } 272 } 273 return res; 274} 275 276/* 277 * Check whether the cname is a permitted replacement for the hostname 278 * and perform the replacement if it is. 279 * NB. this function must operate with a options having undefined members. 280 */ 281static int 282check_follow_cname(char **namep, const char *cname) 283{ 284 int i; 285 struct allowed_cname *rule; 286 287 if (*cname == '\0' || options.num_permitted_cnames == 0 || 288 strcmp(*namep, cname) == 0) 289 return 0; 290 if (options.canonicalize_hostname == SSH_CANONICALISE_NO) 291 return 0; 292 /* 293 * Don't attempt to canonicalize names that will be interpreted by 294 * a proxy unless the user specifically requests so. 295 */ 296 if (!option_clear_or_none(options.proxy_command) && 297 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS) 298 return 0; 299 debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname); 300 for (i = 0; i < options.num_permitted_cnames; i++) { 301 rule = options.permitted_cnames + i; 302 if (match_pattern_list(*namep, rule->source_list, 303 strlen(rule->source_list), 1) != 1 || 304 match_pattern_list(cname, rule->target_list, 305 strlen(rule->target_list), 1) != 1) 306 continue; 307 verbose("Canonicalized DNS aliased hostname " 308 "\"%s\" => \"%s\"", *namep, cname); 309 free(*namep); 310 *namep = xstrdup(cname); 311 return 1; 312 } 313 return 0; 314} 315 316/* 317 * Attempt to resolve the supplied hostname after applying the user's 318 * canonicalization rules. Returns the address list for the host or NULL 319 * if no name was found after canonicalization. 320 * NB. this function must operate with a options having undefined members. 321 */ 322static struct addrinfo * 323resolve_canonicalize(char **hostp, int port) 324{ 325 int i, ndots; 326 char *cp, *fullhost, cname_target[NI_MAXHOST]; 327 struct addrinfo *addrs; 328 329 if (options.canonicalize_hostname == SSH_CANONICALISE_NO) 330 return NULL; 331 332 /* 333 * Don't attempt to canonicalize names that will be interpreted by 334 * a proxy unless the user specifically requests so. 335 */ 336 if (!option_clear_or_none(options.proxy_command) && 337 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS) 338 return NULL; 339 340 /* Don't apply canonicalization to sufficiently-qualified hostnames */ 341 ndots = 0; 342 for (cp = *hostp; *cp != '\0'; cp++) { 343 if (*cp == '.') 344 ndots++; 345 } 346 if (ndots > options.canonicalize_max_dots) { 347 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)", 348 __func__, *hostp, options.canonicalize_max_dots); 349 return NULL; 350 } 351 /* Attempt each supplied suffix */ 352 for (i = 0; i < options.num_canonical_domains; i++) { 353 *cname_target = '\0'; 354 xasprintf(&fullhost, "%s.%s.", *hostp, 355 options.canonical_domains[i]); 356 debug3("%s: attempting \"%s\" => \"%s\"", __func__, 357 *hostp, fullhost); 358 if ((addrs = resolve_host(fullhost, port, 0, 359 cname_target, sizeof(cname_target))) == NULL) { 360 free(fullhost); 361 continue; 362 } 363 /* Remove trailing '.' */ 364 fullhost[strlen(fullhost) - 1] = '\0'; 365 /* Follow CNAME if requested */ 366 if (!check_follow_cname(&fullhost, cname_target)) { 367 debug("Canonicalized hostname \"%s\" => \"%s\"", 368 *hostp, fullhost); 369 } 370 free(*hostp); 371 *hostp = fullhost; 372 return addrs; 373 } 374 if (!options.canonicalize_fallback_local) 375 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp); 376 debug2("%s: host %s not found in any suffix", __func__, *hostp); 377 return NULL; 378} 379 380/* 381 * Read per-user configuration file. Ignore the system wide config 382 * file if the user specifies a config file on the command line. 383 */ 384static void 385process_config_files(struct passwd *pw) 386{ 387 char buf[MAXPATHLEN]; 388 int r; 389 390 if (config != NULL) { 391 if (strcasecmp(config, "none") != 0 && 392 !read_config_file(config, pw, host, &options, 393 SSHCONF_USERCONF)) 394 fatal("Can't open user config file %.100s: " 395 "%.100s", config, strerror(errno)); 396 } else { 397 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, 398 _PATH_SSH_USER_CONFFILE); 399 if (r > 0 && (size_t)r < sizeof(buf)) 400 (void)read_config_file(buf, pw, host, &options, 401 SSHCONF_CHECKPERM|SSHCONF_USERCONF); 402 403 /* Read systemwide configuration file after user config. */ 404 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, host, 405 &options, 0); 406 } 407} 408 409/* 410 * Main program for the ssh client. 411 */ 412int 413main(int ac, char **av) 414{ 415 int i, r, opt, exit_status, use_syslog; 416 char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg, *logfile; 417 char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV]; 418 char cname[NI_MAXHOST]; 419 struct stat st; 420 struct passwd *pw; 421 int timeout_ms; 422 extern int optind, optreset; 423 extern char *optarg; 424 Forward fwd; 425 struct addrinfo *addrs = NULL; 426 427 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 428 sanitise_stdfd(); 429 430 __progname = ssh_get_progname(av[0]); 431 432#ifndef HAVE_SETPROCTITLE 433 /* Prepare for later setproctitle emulation */ 434 /* Save argv so it isn't clobbered by setproctitle() emulation */ 435 saved_av = xcalloc(ac + 1, sizeof(*saved_av)); 436 for (i = 0; i < ac; i++) 437 saved_av[i] = xstrdup(av[i]); 438 saved_av[i] = NULL; 439 compat_init_setproctitle(ac, av); 440 av = saved_av; 441#endif 442 443 /* 444 * Discard other fds that are hanging around. These can cause problem 445 * with backgrounded ssh processes started by ControlPersist. 446 */ 447 closefrom(STDERR_FILENO + 1); 448 449 /* 450 * Save the original real uid. It will be needed later (uid-swapping 451 * may clobber the real uid). 452 */ 453 original_real_uid = getuid(); 454 original_effective_uid = geteuid(); 455 456 /* 457 * Use uid-swapping to give up root privileges for the duration of 458 * option processing. We will re-instantiate the rights when we are 459 * ready to create the privileged port, and will permanently drop 460 * them when the port has been created (actually, when the connection 461 * has been made, as we may need to create the port several times). 462 */ 463 PRIV_END; 464 465#ifdef HAVE_SETRLIMIT 466 /* If we are installed setuid root be careful to not drop core. */ 467 if (original_real_uid != original_effective_uid) { 468 struct rlimit rlim; 469 rlim.rlim_cur = rlim.rlim_max = 0; 470 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 471 fatal("setrlimit failed: %.100s", strerror(errno)); 472 } 473#endif 474 /* Get user data. */ 475 pw = getpwuid(original_real_uid); 476 if (!pw) { 477 logit("No user exists for uid %lu", (u_long)original_real_uid); 478 exit(255); 479 } 480 /* Take a copy of the returned structure. */ 481 pw = pwcopy(pw); 482 483 /* 484 * Set our umask to something reasonable, as some files are created 485 * with the default umask. This will make them world-readable but 486 * writable only by the owner, which is ok for all files for which we 487 * don't set the modes explicitly. 488 */ 489 umask(022); 490 491 /* 492 * Initialize option structure to indicate that no values have been 493 * set. 494 */ 495 initialize_options(&options); 496 497 /* Parse command-line arguments. */ 498 host = NULL; 499 use_syslog = 0; 500 logfile = NULL; 501 argv0 = av[0]; 502 503 again: 504 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 505 "ACD:E:F:I:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) { 506 switch (opt) { 507 case '1': 508 options.protocol = SSH_PROTO_1; 509 break; 510 case '2': 511 options.protocol = SSH_PROTO_2; 512 break; 513 case '4': 514 options.address_family = AF_INET; 515 break; 516 case '6': 517 options.address_family = AF_INET6; 518 break; 519 case 'n': 520 stdin_null_flag = 1; 521 break; 522 case 'f': 523 fork_after_authentication_flag = 1; 524 stdin_null_flag = 1; 525 break; 526 case 'x': 527 options.forward_x11 = 0; 528 break; 529 case 'X': 530 options.forward_x11 = 1; 531 break; 532 case 'y': 533 use_syslog = 1; 534 break; 535 case 'E': 536 logfile = xstrdup(optarg); 537 break; 538 case 'Y': 539 options.forward_x11 = 1; 540 options.forward_x11_trusted = 1; 541 break; 542 case 'g': 543 options.gateway_ports = 1; 544 break; 545 case 'O': 546 if (stdio_forward_host != NULL) 547 fatal("Cannot specify multiplexing " 548 "command with -W"); 549 else if (muxclient_command != 0) 550 fatal("Multiplexing command already specified"); 551 if (strcmp(optarg, "check") == 0) 552 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; 553 else if (strcmp(optarg, "forward") == 0) 554 muxclient_command = SSHMUX_COMMAND_FORWARD; 555 else if (strcmp(optarg, "exit") == 0) 556 muxclient_command = SSHMUX_COMMAND_TERMINATE; 557 else if (strcmp(optarg, "stop") == 0) 558 muxclient_command = SSHMUX_COMMAND_STOP; 559 else if (strcmp(optarg, "cancel") == 0) 560 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD; 561 else 562 fatal("Invalid multiplex command."); 563 break; 564 case 'P': /* deprecated */ 565 options.use_privileged_port = 0; 566 break; 567 case 'Q': 568 cp = NULL; 569 if (strcmp(optarg, "cipher") == 0) 570 cp = cipher_alg_list('\n', 0); 571 else if (strcmp(optarg, "cipher-auth") == 0) 572 cp = cipher_alg_list('\n', 1); 573 else if (strcmp(optarg, "mac") == 0) 574 cp = mac_alg_list('\n'); 575 else if (strcmp(optarg, "kex") == 0) 576 cp = kex_alg_list('\n'); 577 else if (strcmp(optarg, "key") == 0) 578 cp = key_alg_list(0, 0); 579 else if (strcmp(optarg, "key-cert") == 0) 580 cp = key_alg_list(1, 0); 581 else if (strcmp(optarg, "key-plain") == 0) 582 cp = key_alg_list(0, 1); 583 if (cp == NULL) 584 fatal("Unsupported query \"%s\"", optarg); 585 printf("%s\n", cp); 586 free(cp); 587 exit(0); 588 break; 589 case 'a': 590 options.forward_agent = 0; 591 break; 592 case 'A': 593 options.forward_agent = 1; 594 break; 595 case 'k': 596 options.gss_deleg_creds = 0; 597 break; 598 case 'K': 599 options.gss_authentication = 1; 600 options.gss_deleg_creds = 1; 601 break; 602 case 'i': 603 if (stat(optarg, &st) < 0) { 604 fprintf(stderr, "Warning: Identity file %s " 605 "not accessible: %s.\n", optarg, 606 strerror(errno)); 607 break; 608 } 609 add_identity_file(&options, NULL, optarg, 1); 610 break; 611 case 'I': 612#ifdef ENABLE_PKCS11 613 options.pkcs11_provider = xstrdup(optarg); 614#else 615 fprintf(stderr, "no support for PKCS#11.\n"); 616#endif 617 break; 618 case 't': 619 if (options.request_tty == REQUEST_TTY_YES) 620 options.request_tty = REQUEST_TTY_FORCE; 621 else 622 options.request_tty = REQUEST_TTY_YES; 623 break; 624 case 'v': 625 if (debug_flag == 0) { 626 debug_flag = 1; 627 options.log_level = SYSLOG_LEVEL_DEBUG1; 628 } else { 629 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 630 options.log_level++; 631 } 632 break; 633 case 'V': 634 if (options.version_addendum && 635 *options.version_addendum != '\0') 636 fprintf(stderr, "%s %s, %s\n", SSH_RELEASE, 637 options.version_addendum, 638 SSLeay_version(SSLEAY_VERSION)); 639 else 640 fprintf(stderr, "%s, %s\n", SSH_RELEASE, 641 SSLeay_version(SSLEAY_VERSION)); 642 if (opt == 'V') 643 exit(0); 644 break; 645 case 'w': 646 if (options.tun_open == -1) 647 options.tun_open = SSH_TUNMODE_DEFAULT; 648 options.tun_local = a2tun(optarg, &options.tun_remote); 649 if (options.tun_local == SSH_TUNID_ERR) { 650 fprintf(stderr, 651 "Bad tun device '%s'\n", optarg); 652 exit(255); 653 } 654 break; 655 case 'W': 656 if (stdio_forward_host != NULL) 657 fatal("stdio forward already specified"); 658 if (muxclient_command != 0) 659 fatal("Cannot specify stdio forward with -O"); 660 if (parse_forward(&fwd, optarg, 1, 0)) { 661 stdio_forward_host = fwd.listen_host; 662 stdio_forward_port = fwd.listen_port; 663 free(fwd.connect_host); 664 } else { 665 fprintf(stderr, 666 "Bad stdio forwarding specification '%s'\n", 667 optarg); 668 exit(255); 669 } 670 options.request_tty = REQUEST_TTY_NO; 671 no_shell_flag = 1; 672 options.clear_forwardings = 1; 673 options.exit_on_forward_failure = 1; 674 break; 675 case 'q': 676 options.log_level = SYSLOG_LEVEL_QUIET; 677 break; 678 case 'e': 679 if (optarg[0] == '^' && optarg[2] == 0 && 680 (u_char) optarg[1] >= 64 && 681 (u_char) optarg[1] < 128) 682 options.escape_char = (u_char) optarg[1] & 31; 683 else if (strlen(optarg) == 1) 684 options.escape_char = (u_char) optarg[0]; 685 else if (strcmp(optarg, "none") == 0) 686 options.escape_char = SSH_ESCAPECHAR_NONE; 687 else { 688 fprintf(stderr, "Bad escape character '%s'.\n", 689 optarg); 690 exit(255); 691 } 692 break; 693 case 'c': 694 if (ciphers_valid(optarg)) { 695 /* SSH2 only */ 696 options.ciphers = xstrdup(optarg); 697 options.cipher = SSH_CIPHER_INVALID; 698 } else { 699 /* SSH1 only */ 700 options.cipher = cipher_number(optarg); 701 if (options.cipher == -1) { 702 fprintf(stderr, 703 "Unknown cipher type '%s'\n", 704 optarg); 705 exit(255); 706 } 707 if (options.cipher == SSH_CIPHER_3DES) 708 options.ciphers = "3des-cbc"; 709 else if (options.cipher == SSH_CIPHER_BLOWFISH) 710 options.ciphers = "blowfish-cbc"; 711 else 712 options.ciphers = (char *)-1; 713 } 714 break; 715 case 'm': 716 if (mac_valid(optarg)) 717 options.macs = xstrdup(optarg); 718 else { 719 fprintf(stderr, "Unknown mac type '%s'\n", 720 optarg); 721 exit(255); 722 } 723 break; 724 case 'M': 725 if (options.control_master == SSHCTL_MASTER_YES) 726 options.control_master = SSHCTL_MASTER_ASK; 727 else 728 options.control_master = SSHCTL_MASTER_YES; 729 break; 730 case 'p': 731 options.port = a2port(optarg); 732 if (options.port <= 0) { 733 fprintf(stderr, "Bad port '%s'\n", optarg); 734 exit(255); 735 } 736 break; 737 case 'l': 738 options.user = optarg; 739 break; 740 741 case 'L': 742 if (parse_forward(&fwd, optarg, 0, 0)) 743 add_local_forward(&options, &fwd); 744 else { 745 fprintf(stderr, 746 "Bad local forwarding specification '%s'\n", 747 optarg); 748 exit(255); 749 } 750 break; 751 752 case 'R': 753 if (parse_forward(&fwd, optarg, 0, 1)) { 754 add_remote_forward(&options, &fwd); 755 } else { 756 fprintf(stderr, 757 "Bad remote forwarding specification " 758 "'%s'\n", optarg); 759 exit(255); 760 } 761 break; 762 763 case 'D': 764 if (parse_forward(&fwd, optarg, 1, 0)) { 765 add_local_forward(&options, &fwd); 766 } else { 767 fprintf(stderr, 768 "Bad dynamic forwarding specification " 769 "'%s'\n", optarg); 770 exit(255); 771 } 772 break; 773 774 case 'C': 775 options.compression = 1; 776 break; 777 case 'N': 778 no_shell_flag = 1; 779 options.request_tty = REQUEST_TTY_NO; 780 break; 781 case 'T': 782 options.request_tty = REQUEST_TTY_NO; 783 break; 784 case 'o': 785 line = xstrdup(optarg); 786 if (process_config_line(&options, pw, host ? host : "", 787 line, "command-line", 0, NULL, SSHCONF_USERCONF) 788 != 0) 789 exit(255); 790 free(line); 791 break; 792 case 's': 793 subsystem_flag = 1; 794 break; 795 case 'S': 796 if (options.control_path != NULL) 797 free(options.control_path); 798 options.control_path = xstrdup(optarg); 799 break; 800 case 'b': 801 options.bind_address = optarg; 802 break; 803 case 'F': 804 config = optarg; 805 break; 806 default: 807 usage(); 808 } 809 } 810 811 ac -= optind; 812 av += optind; 813 814 if (ac > 0 && !host) { 815 if (strrchr(*av, '@')) { 816 p = xstrdup(*av); 817 cp = strrchr(p, '@'); 818 if (cp == NULL || cp == p) 819 usage(); 820 options.user = p; 821 *cp = '\0'; 822 host = xstrdup(++cp); 823 } else 824 host = xstrdup(*av); 825 if (ac > 1) { 826 optind = optreset = 1; 827 goto again; 828 } 829 ac--, av++; 830 } 831 832 /* Check that we got a host name. */ 833 if (!host) 834 usage(); 835 836 host_arg = xstrdup(host); 837 838 OpenSSL_add_all_algorithms(); 839 ERR_load_crypto_strings(); 840 841 /* Initialize the command to execute on remote host. */ 842 buffer_init(&command); 843 844 /* 845 * Save the command to execute on the remote host in a buffer. There 846 * is no limit on the length of the command, except by the maximum 847 * packet size. Also sets the tty flag if there is no command. 848 */ 849 if (!ac) { 850 /* No command specified - execute shell on a tty. */ 851 if (subsystem_flag) { 852 fprintf(stderr, 853 "You must specify a subsystem to invoke.\n"); 854 usage(); 855 } 856 } else { 857 /* A command has been specified. Store it into the buffer. */ 858 for (i = 0; i < ac; i++) { 859 if (i) 860 buffer_append(&command, " ", 1); 861 buffer_append(&command, av[i], strlen(av[i])); 862 } 863 } 864 865 /* Cannot fork to background if no command. */ 866 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 867 !no_shell_flag) 868 fatal("Cannot fork into background without a command " 869 "to execute."); 870 871 /* 872 * Initialize "log" output. Since we are the client all output 873 * goes to stderr unless otherwise specified by -y or -E. 874 */ 875 if (use_syslog && logfile != NULL) 876 fatal("Can't specify both -y and -E"); 877 if (logfile != NULL) { 878 log_redirect_stderr_to(logfile); 879 free(logfile); 880 } 881 log_init(argv0, 882 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 883 SYSLOG_FACILITY_USER, !use_syslog); 884 885 if (debug_flag) 886 logit("%s, %s", SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); 887 888 /* Parse the configuration files */ 889 process_config_files(pw); 890 891 /* Hostname canonicalisation needs a few options filled. */ 892 fill_default_options_for_canonicalization(&options); 893 894 /* If the user has replaced the hostname then take it into use now */ 895 if (options.hostname != NULL) { 896 /* NB. Please keep in sync with readconf.c:match_cfg_line() */ 897 cp = percent_expand(options.hostname, 898 "h", host, (char *)NULL); 899 free(host); 900 host = cp; 901 } 902 903 /* If canonicalization requested then try to apply it */ 904 lowercase(host); 905 if (options.canonicalize_hostname != SSH_CANONICALISE_NO) 906 addrs = resolve_canonicalize(&host, options.port); 907 908 /* 909 * If CanonicalizePermittedCNAMEs have been specified but 910 * other canonicalization did not happen (by not being requested 911 * or by failing with fallback) then the hostname may still be changed 912 * as a result of CNAME following. 913 * 914 * Try to resolve the bare hostname name using the system resolver's 915 * usual search rules and then apply the CNAME follow rules. 916 * 917 * Skip the lookup if a ProxyCommand is being used unless the user 918 * has specifically requested canonicalisation for this case via 919 * CanonicalizeHostname=always 920 */ 921 if (addrs == NULL && options.num_permitted_cnames != 0 && 922 (option_clear_or_none(options.proxy_command) || 923 options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) { 924 if ((addrs = resolve_host(host, options.port, 1, 925 cname, sizeof(cname))) == NULL) 926 cleanup_exit(255); /* resolve_host logs the error */ 927 check_follow_cname(&host, cname); 928 } 929 930 /* 931 * If the target hostname has changed as a result of canonicalisation 932 * then re-parse the configuration files as new stanzas may match. 933 */ 934 if (strcasecmp(host_arg, host) != 0) { 935 debug("Hostname has changed; re-reading configuration"); 936 process_config_files(pw); 937 } 938 939 /* Fill configuration defaults. */ 940 fill_default_options(&options); 941 942 if (options.port == 0) 943 options.port = default_ssh_port(); 944 channel_set_af(options.address_family); 945 946 /* Tidy and check options */ 947 if (options.host_key_alias != NULL) 948 lowercase(options.host_key_alias); 949 if (options.proxy_command != NULL && 950 strcmp(options.proxy_command, "-") == 0 && 951 options.proxy_use_fdpass) 952 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible"); 953#ifndef HAVE_CYGWIN 954 if (original_effective_uid != 0) 955 options.use_privileged_port = 0; 956#endif 957 958 /* reinit */ 959 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 960 961 if (options.request_tty == REQUEST_TTY_YES || 962 options.request_tty == REQUEST_TTY_FORCE) 963 tty_flag = 1; 964 965 /* Allocate a tty by default if no command specified. */ 966 if (buffer_len(&command) == 0) 967 tty_flag = options.request_tty != REQUEST_TTY_NO; 968 969 /* Force no tty */ 970 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0) 971 tty_flag = 0; 972 /* Do not allocate a tty if stdin is not a tty. */ 973 if ((!isatty(fileno(stdin)) || stdin_null_flag) && 974 options.request_tty != REQUEST_TTY_FORCE) { 975 if (tty_flag) 976 logit("Pseudo-terminal will not be allocated because " 977 "stdin is not a terminal."); 978 tty_flag = 0; 979 } 980 981 seed_rng(); 982 983 if (options.user == NULL) 984 options.user = xstrdup(pw->pw_name); 985 986 if (gethostname(thishost, sizeof(thishost)) == -1) 987 fatal("gethostname: %s", strerror(errno)); 988 strlcpy(shorthost, thishost, sizeof(shorthost)); 989 shorthost[strcspn(thishost, ".")] = '\0'; 990 snprintf(portstr, sizeof(portstr), "%d", options.port); 991 992 /* Find canonic host name. */ 993 if (strchr(host, '.') == 0) { 994 struct addrinfo hints; 995 struct addrinfo *ai = NULL; 996 int errgai; 997 memset(&hints, 0, sizeof(hints)); 998 hints.ai_family = options.address_family; 999 hints.ai_flags = AI_CANONNAME; 1000 hints.ai_socktype = SOCK_STREAM; 1001 errgai = getaddrinfo(host, NULL, &hints, &ai); 1002 if (errgai == 0) { 1003 if (ai->ai_canonname != NULL) 1004 host = xstrdup(ai->ai_canonname); 1005 freeaddrinfo(ai); 1006 } 1007 } 1008 1009 if (options.local_command != NULL) { 1010 debug3("expanding LocalCommand: %s", options.local_command); 1011 cp = options.local_command; 1012 options.local_command = percent_expand(cp, "d", pw->pw_dir, 1013 "h", host, "l", thishost, "n", host_arg, "r", options.user, 1014 "p", portstr, "u", pw->pw_name, "L", shorthost, 1015 (char *)NULL); 1016 debug3("expanded LocalCommand: %s", options.local_command); 1017 free(cp); 1018 } 1019 1020 if (options.control_path != NULL) { 1021 cp = tilde_expand_filename(options.control_path, 1022 original_real_uid); 1023 free(options.control_path); 1024 options.control_path = percent_expand(cp, "h", host, 1025 "l", thishost, "n", host_arg, "r", options.user, 1026 "p", portstr, "u", pw->pw_name, "L", shorthost, 1027 (char *)NULL); 1028 free(cp); 1029 } 1030 if (muxclient_command != 0 && options.control_path == NULL) 1031 fatal("No ControlPath specified for \"-O\" command"); 1032 if (options.control_path != NULL) 1033 muxclient(options.control_path); 1034 1035 /* 1036 * If hostname canonicalisation was not enabled, then we may not 1037 * have yet resolved the hostname. Do so now. 1038 */ 1039 if (addrs == NULL && options.proxy_command == NULL) { 1040 if ((addrs = resolve_host(host, options.port, 1, 1041 cname, sizeof(cname))) == NULL) 1042 cleanup_exit(255); /* resolve_host logs the error */ 1043 } 1044 1045 timeout_ms = options.connection_timeout * 1000; 1046 1047 /* Open a connection to the remote host. */ 1048 if (ssh_connect(host, addrs, &hostaddr, options.port, 1049 options.address_family, options.connection_attempts, 1050 &timeout_ms, options.tcp_keep_alive, 1051 options.use_privileged_port) != 0) 1052 exit(255); 1053 1054 if (addrs != NULL) 1055 freeaddrinfo(addrs); 1056 1057 packet_set_timeout(options.server_alive_interval, 1058 options.server_alive_count_max); 1059 1060 if (timeout_ms > 0) 1061 debug3("timeout: %d ms remain after connect", timeout_ms); 1062 1063 /* 1064 * If we successfully made the connection, load the host private key 1065 * in case we will need it later for combined rsa-rhosts 1066 * authentication. This must be done before releasing extra 1067 * privileges, because the file is only readable by root. 1068 * If we cannot access the private keys, load the public keys 1069 * instead and try to execute the ssh-keysign helper instead. 1070 */ 1071 sensitive_data.nkeys = 0; 1072 sensitive_data.keys = NULL; 1073 sensitive_data.external_keysign = 0; 1074 if (options.rhosts_rsa_authentication || 1075 options.hostbased_authentication) { 1076 sensitive_data.nkeys = 9; 1077 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 1078 sizeof(Key)); 1079 for (i = 0; i < sensitive_data.nkeys; i++) 1080 sensitive_data.keys[i] = NULL; 1081 1082 PRIV_START; 1083 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 1084 _PATH_HOST_KEY_FILE, "", NULL, NULL); 1085 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA, 1086 _PATH_HOST_DSA_KEY_FILE, "", NULL); 1087#ifdef OPENSSL_HAS_ECC 1088 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA, 1089 _PATH_HOST_ECDSA_KEY_FILE, "", NULL); 1090#endif 1091 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA, 1092 _PATH_HOST_RSA_KEY_FILE, "", NULL); 1093 sensitive_data.keys[4] = key_load_private_cert(KEY_ED25519, 1094 _PATH_HOST_ED25519_KEY_FILE, "", NULL); 1095 sensitive_data.keys[5] = key_load_private_type(KEY_DSA, 1096 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 1097#ifdef OPENSSL_HAS_ECC 1098 sensitive_data.keys[6] = key_load_private_type(KEY_ECDSA, 1099 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL); 1100#endif 1101 sensitive_data.keys[7] = key_load_private_type(KEY_RSA, 1102 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 1103 sensitive_data.keys[8] = key_load_private_type(KEY_ED25519, 1104 _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL); 1105 PRIV_END; 1106 1107 if (options.hostbased_authentication == 1 && 1108 sensitive_data.keys[0] == NULL && 1109 sensitive_data.keys[5] == NULL && 1110 sensitive_data.keys[6] == NULL && 1111 sensitive_data.keys[7] == NULL && 1112 sensitive_data.keys[8] == NULL) { 1113 sensitive_data.keys[1] = key_load_cert( 1114 _PATH_HOST_DSA_KEY_FILE); 1115#ifdef OPENSSL_HAS_ECC 1116 sensitive_data.keys[2] = key_load_cert( 1117 _PATH_HOST_ECDSA_KEY_FILE); 1118#endif 1119 sensitive_data.keys[3] = key_load_cert( 1120 _PATH_HOST_RSA_KEY_FILE); 1121 sensitive_data.keys[4] = key_load_cert( 1122 _PATH_HOST_ED25519_KEY_FILE); 1123 sensitive_data.keys[5] = key_load_public( 1124 _PATH_HOST_DSA_KEY_FILE, NULL); 1125#ifdef OPENSSL_HAS_ECC 1126 sensitive_data.keys[6] = key_load_public( 1127 _PATH_HOST_ECDSA_KEY_FILE, NULL); 1128#endif 1129 sensitive_data.keys[7] = key_load_public( 1130 _PATH_HOST_RSA_KEY_FILE, NULL); 1131 sensitive_data.keys[8] = key_load_public( 1132 _PATH_HOST_ED25519_KEY_FILE, NULL); 1133 sensitive_data.external_keysign = 1; 1134 } 1135 } 1136 /* 1137 * Get rid of any extra privileges that we may have. We will no 1138 * longer need them. Also, extra privileges could make it very hard 1139 * to read identity files and other non-world-readable files from the 1140 * user's home directory if it happens to be on a NFS volume where 1141 * root is mapped to nobody. 1142 */ 1143 if (original_effective_uid == 0) { 1144 PRIV_START; 1145 permanently_set_uid(pw); 1146 } 1147 1148 /* 1149 * Now that we are back to our own permissions, create ~/.ssh 1150 * directory if it doesn't already exist. 1151 */ 1152 if (config == NULL) { 1153 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 1154 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 1155 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) { 1156#ifdef WITH_SELINUX 1157 ssh_selinux_setfscreatecon(buf); 1158#endif 1159 if (mkdir(buf, 0700) < 0) 1160 error("Could not create directory '%.200s'.", 1161 buf); 1162#ifdef WITH_SELINUX 1163 ssh_selinux_setfscreatecon(NULL); 1164#endif 1165 } 1166 } 1167 /* load options.identity_files */ 1168 load_public_identity_files(); 1169 1170 /* Expand ~ in known host file names. */ 1171 tilde_expand_paths(options.system_hostfiles, 1172 options.num_system_hostfiles); 1173 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles); 1174 1175 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 1176 signal(SIGCHLD, main_sigchld_handler); 1177 1178 /* Log into the remote system. Never returns if the login fails. */ 1179 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 1180 options.port, pw, timeout_ms); 1181 1182 if (packet_connection_is_on_socket()) { 1183 verbose("Authenticated to %s ([%s]:%d).", host, 1184 get_remote_ipaddr(), get_remote_port()); 1185 } else { 1186 verbose("Authenticated to %s (via proxy).", host); 1187 } 1188 1189 /* We no longer need the private host keys. Clear them now. */ 1190 if (sensitive_data.nkeys != 0) { 1191 for (i = 0; i < sensitive_data.nkeys; i++) { 1192 if (sensitive_data.keys[i] != NULL) { 1193 /* Destroys contents safely */ 1194 debug3("clear hostkey %d", i); 1195 key_free(sensitive_data.keys[i]); 1196 sensitive_data.keys[i] = NULL; 1197 } 1198 } 1199 free(sensitive_data.keys); 1200 } 1201 for (i = 0; i < options.num_identity_files; i++) { 1202 free(options.identity_files[i]); 1203 options.identity_files[i] = NULL; 1204 if (options.identity_keys[i]) { 1205 key_free(options.identity_keys[i]); 1206 options.identity_keys[i] = NULL; 1207 } 1208 } 1209 1210 exit_status = compat20 ? ssh_session2() : ssh_session(); 1211 packet_close(); 1212 1213 if (options.control_path != NULL && muxserver_sock != -1) 1214 unlink(options.control_path); 1215 1216 /* Kill ProxyCommand if it is running. */ 1217 ssh_kill_proxy_command(); 1218 1219 return exit_status; 1220} 1221 1222static void 1223control_persist_detach(void) 1224{ 1225 pid_t pid; 1226 int devnull; 1227 1228 debug("%s: backgrounding master process", __func__); 1229 1230 /* 1231 * master (current process) into the background, and make the 1232 * foreground process a client of the backgrounded master. 1233 */ 1234 switch ((pid = fork())) { 1235 case -1: 1236 fatal("%s: fork: %s", __func__, strerror(errno)); 1237 case 0: 1238 /* Child: master process continues mainloop */ 1239 break; 1240 default: 1241 /* Parent: set up mux slave to connect to backgrounded master */ 1242 debug2("%s: background process is %ld", __func__, (long)pid); 1243 stdin_null_flag = ostdin_null_flag; 1244 options.request_tty = orequest_tty; 1245 tty_flag = otty_flag; 1246 close(muxserver_sock); 1247 muxserver_sock = -1; 1248 options.control_master = SSHCTL_MASTER_NO; 1249 muxclient(options.control_path); 1250 /* muxclient() doesn't return on success. */ 1251 fatal("Failed to connect to new control master"); 1252 } 1253 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { 1254 error("%s: open(\"/dev/null\"): %s", __func__, 1255 strerror(errno)); 1256 } else { 1257 if (dup2(devnull, STDIN_FILENO) == -1 || 1258 dup2(devnull, STDOUT_FILENO) == -1) 1259 error("%s: dup2: %s", __func__, strerror(errno)); 1260 if (devnull > STDERR_FILENO) 1261 close(devnull); 1262 } 1263 daemon(1, 1); 1264 setproctitle("%s [mux]", options.control_path); 1265} 1266 1267/* Do fork() after authentication. Used by "ssh -f" */ 1268static void 1269fork_postauth(void) 1270{ 1271 if (need_controlpersist_detach) 1272 control_persist_detach(); 1273 debug("forking to background"); 1274 fork_after_authentication_flag = 0; 1275 if (daemon(1, 1) < 0) 1276 fatal("daemon() failed: %.200s", strerror(errno)); 1277} 1278 1279/* Callback for remote forward global requests */ 1280static void 1281ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 1282{ 1283 Forward *rfwd = (Forward *)ctxt; 1284 1285 /* XXX verbose() on failure? */ 1286 debug("remote forward %s for: listen %d, connect %s:%d", 1287 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 1288 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 1289 if (rfwd->listen_port == 0) { 1290 if (type == SSH2_MSG_REQUEST_SUCCESS) { 1291 rfwd->allocated_port = packet_get_int(); 1292 logit("Allocated port %u for remote forward to %s:%d", 1293 rfwd->allocated_port, 1294 rfwd->connect_host, rfwd->connect_port); 1295 channel_update_permitted_opens(rfwd->handle, 1296 rfwd->allocated_port); 1297 } else { 1298 channel_update_permitted_opens(rfwd->handle, -1); 1299 } 1300 } 1301 1302 if (type == SSH2_MSG_REQUEST_FAILURE) { 1303 if (options.exit_on_forward_failure) 1304 fatal("Error: remote port forwarding failed for " 1305 "listen port %d", rfwd->listen_port); 1306 else 1307 logit("Warning: remote port forwarding failed for " 1308 "listen port %d", rfwd->listen_port); 1309 } 1310 if (++remote_forward_confirms_received == options.num_remote_forwards) { 1311 debug("All remote forwarding requests processed"); 1312 if (fork_after_authentication_flag) 1313 fork_postauth(); 1314 } 1315} 1316 1317static void 1318client_cleanup_stdio_fwd(int id, void *arg) 1319{ 1320 debug("stdio forwarding: done"); 1321 cleanup_exit(0); 1322} 1323 1324static void 1325ssh_init_stdio_forwarding(void) 1326{ 1327 Channel *c; 1328 int in, out; 1329 1330 if (stdio_forward_host == NULL) 1331 return; 1332 if (!compat20) 1333 fatal("stdio forwarding require Protocol 2"); 1334 1335 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port); 1336 1337 if ((in = dup(STDIN_FILENO)) < 0 || 1338 (out = dup(STDOUT_FILENO)) < 0) 1339 fatal("channel_connect_stdio_fwd: dup() in/out failed"); 1340 if ((c = channel_connect_stdio_fwd(stdio_forward_host, 1341 stdio_forward_port, in, out)) == NULL) 1342 fatal("%s: channel_connect_stdio_fwd failed", __func__); 1343 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0); 1344} 1345 1346static void 1347ssh_init_forwarding(void) 1348{ 1349 int success = 0; 1350 int i; 1351 1352 /* Initiate local TCP/IP port forwardings. */ 1353 for (i = 0; i < options.num_local_forwards; i++) { 1354 debug("Local connections to %.200s:%d forwarded to remote " 1355 "address %.200s:%d", 1356 (options.local_forwards[i].listen_host == NULL) ? 1357 (options.gateway_ports ? "*" : "LOCALHOST") : 1358 options.local_forwards[i].listen_host, 1359 options.local_forwards[i].listen_port, 1360 options.local_forwards[i].connect_host, 1361 options.local_forwards[i].connect_port); 1362 success += channel_setup_local_fwd_listener( 1363 options.local_forwards[i].listen_host, 1364 options.local_forwards[i].listen_port, 1365 options.local_forwards[i].connect_host, 1366 options.local_forwards[i].connect_port, 1367 options.gateway_ports); 1368 } 1369 if (i > 0 && success != i && options.exit_on_forward_failure) 1370 fatal("Could not request local forwarding."); 1371 if (i > 0 && success == 0) 1372 error("Could not request local forwarding."); 1373 1374 /* Initiate remote TCP/IP port forwardings. */ 1375 for (i = 0; i < options.num_remote_forwards; i++) { 1376 debug("Remote connections from %.200s:%d forwarded to " 1377 "local address %.200s:%d", 1378 (options.remote_forwards[i].listen_host == NULL) ? 1379 "LOCALHOST" : options.remote_forwards[i].listen_host, 1380 options.remote_forwards[i].listen_port, 1381 options.remote_forwards[i].connect_host, 1382 options.remote_forwards[i].connect_port); 1383 options.remote_forwards[i].handle = 1384 channel_request_remote_forwarding( 1385 options.remote_forwards[i].listen_host, 1386 options.remote_forwards[i].listen_port, 1387 options.remote_forwards[i].connect_host, 1388 options.remote_forwards[i].connect_port); 1389 if (options.remote_forwards[i].handle < 0) { 1390 if (options.exit_on_forward_failure) 1391 fatal("Could not request remote forwarding."); 1392 else 1393 logit("Warning: Could not request remote " 1394 "forwarding."); 1395 } else { 1396 client_register_global_confirm(ssh_confirm_remote_forward, 1397 &options.remote_forwards[i]); 1398 } 1399 } 1400 1401 /* Initiate tunnel forwarding. */ 1402 if (options.tun_open != SSH_TUNMODE_NO) { 1403 if (client_request_tun_fwd(options.tun_open, 1404 options.tun_local, options.tun_remote) == -1) { 1405 if (options.exit_on_forward_failure) 1406 fatal("Could not request tunnel forwarding."); 1407 else 1408 error("Could not request tunnel forwarding."); 1409 } 1410 } 1411} 1412 1413static void 1414check_agent_present(void) 1415{ 1416 if (options.forward_agent) { 1417 /* Clear agent forwarding if we don't have an agent. */ 1418 if (!ssh_agent_present()) 1419 options.forward_agent = 0; 1420 } 1421} 1422 1423static int 1424ssh_session(void) 1425{ 1426 int type; 1427 int interactive = 0; 1428 int have_tty = 0; 1429 struct winsize ws; 1430 char *cp; 1431 const char *display; 1432 1433 /* Enable compression if requested. */ 1434 if (options.compression) { 1435 debug("Requesting compression at level %d.", 1436 options.compression_level); 1437 1438 if (options.compression_level < 1 || 1439 options.compression_level > 9) 1440 fatal("Compression level must be from 1 (fast) to " 1441 "9 (slow, best)."); 1442 1443 /* Send the request. */ 1444 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 1445 packet_put_int(options.compression_level); 1446 packet_send(); 1447 packet_write_wait(); 1448 type = packet_read(); 1449 if (type == SSH_SMSG_SUCCESS) 1450 packet_start_compression(options.compression_level); 1451 else if (type == SSH_SMSG_FAILURE) 1452 logit("Warning: Remote host refused compression."); 1453 else 1454 packet_disconnect("Protocol error waiting for " 1455 "compression response."); 1456 } 1457 /* Allocate a pseudo tty if appropriate. */ 1458 if (tty_flag) { 1459 debug("Requesting pty."); 1460 1461 /* Start the packet. */ 1462 packet_start(SSH_CMSG_REQUEST_PTY); 1463 1464 /* Store TERM in the packet. There is no limit on the 1465 length of the string. */ 1466 cp = getenv("TERM"); 1467 if (!cp) 1468 cp = ""; 1469 packet_put_cstring(cp); 1470 1471 /* Store window size in the packet. */ 1472 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1473 memset(&ws, 0, sizeof(ws)); 1474 packet_put_int((u_int)ws.ws_row); 1475 packet_put_int((u_int)ws.ws_col); 1476 packet_put_int((u_int)ws.ws_xpixel); 1477 packet_put_int((u_int)ws.ws_ypixel); 1478 1479 /* Store tty modes in the packet. */ 1480 tty_make_modes(fileno(stdin), NULL); 1481 1482 /* Send the packet, and wait for it to leave. */ 1483 packet_send(); 1484 packet_write_wait(); 1485 1486 /* Read response from the server. */ 1487 type = packet_read(); 1488 if (type == SSH_SMSG_SUCCESS) { 1489 interactive = 1; 1490 have_tty = 1; 1491 } else if (type == SSH_SMSG_FAILURE) 1492 logit("Warning: Remote host failed or refused to " 1493 "allocate a pseudo tty."); 1494 else 1495 packet_disconnect("Protocol error waiting for pty " 1496 "request response."); 1497 } 1498 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1499 display = getenv("DISPLAY"); 1500 if (options.forward_x11 && display != NULL) { 1501 char *proto, *data; 1502 /* Get reasonable local authentication information. */ 1503 client_x11_get_proto(display, options.xauth_location, 1504 options.forward_x11_trusted, 1505 options.forward_x11_timeout, 1506 &proto, &data); 1507 /* Request forwarding with authentication spoofing. */ 1508 debug("Requesting X11 forwarding with authentication " 1509 "spoofing."); 1510 x11_request_forwarding_with_spoofing(0, display, proto, 1511 data, 0); 1512 /* Read response from the server. */ 1513 type = packet_read(); 1514 if (type == SSH_SMSG_SUCCESS) { 1515 interactive = 1; 1516 } else if (type == SSH_SMSG_FAILURE) { 1517 logit("Warning: Remote host denied X11 forwarding."); 1518 } else { 1519 packet_disconnect("Protocol error waiting for X11 " 1520 "forwarding"); 1521 } 1522 } 1523 /* Tell the packet module whether this is an interactive session. */ 1524 packet_set_interactive(interactive, 1525 options.ip_qos_interactive, options.ip_qos_bulk); 1526 1527 /* Request authentication agent forwarding if appropriate. */ 1528 check_agent_present(); 1529 1530 if (options.forward_agent) { 1531 debug("Requesting authentication agent forwarding."); 1532 auth_request_forwarding(); 1533 1534 /* Read response from the server. */ 1535 type = packet_read(); 1536 packet_check_eom(); 1537 if (type != SSH_SMSG_SUCCESS) 1538 logit("Warning: Remote host denied authentication agent forwarding."); 1539 } 1540 1541 /* Initiate port forwardings. */ 1542 ssh_init_stdio_forwarding(); 1543 ssh_init_forwarding(); 1544 1545 /* Execute a local command */ 1546 if (options.local_command != NULL && 1547 options.permit_local_command) 1548 ssh_local_cmd(options.local_command); 1549 1550 /* 1551 * If requested and we are not interested in replies to remote 1552 * forwarding requests, then let ssh continue in the background. 1553 */ 1554 if (fork_after_authentication_flag) { 1555 if (options.exit_on_forward_failure && 1556 options.num_remote_forwards > 0) { 1557 debug("deferring postauth fork until remote forward " 1558 "confirmation received"); 1559 } else 1560 fork_postauth(); 1561 } 1562 1563 /* 1564 * If a command was specified on the command line, execute the 1565 * command now. Otherwise request the server to start a shell. 1566 */ 1567 if (buffer_len(&command) > 0) { 1568 int len = buffer_len(&command); 1569 if (len > 900) 1570 len = 900; 1571 debug("Sending command: %.*s", len, 1572 (u_char *)buffer_ptr(&command)); 1573 packet_start(SSH_CMSG_EXEC_CMD); 1574 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1575 packet_send(); 1576 packet_write_wait(); 1577 } else { 1578 debug("Requesting shell."); 1579 packet_start(SSH_CMSG_EXEC_SHELL); 1580 packet_send(); 1581 packet_write_wait(); 1582 } 1583 1584 /* Enter the interactive session. */ 1585 return client_loop(have_tty, tty_flag ? 1586 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1587} 1588 1589/* request pty/x11/agent/tcpfwd/shell for channel */ 1590static void 1591ssh_session2_setup(int id, int success, void *arg) 1592{ 1593 extern char **environ; 1594 const char *display; 1595 int interactive = tty_flag; 1596 1597 if (!success) 1598 return; /* No need for error message, channels code sens one */ 1599 1600 display = getenv("DISPLAY"); 1601 if (options.forward_x11 && display != NULL) { 1602 char *proto, *data; 1603 /* Get reasonable local authentication information. */ 1604 client_x11_get_proto(display, options.xauth_location, 1605 options.forward_x11_trusted, 1606 options.forward_x11_timeout, &proto, &data); 1607 /* Request forwarding with authentication spoofing. */ 1608 debug("Requesting X11 forwarding with authentication " 1609 "spoofing."); 1610 x11_request_forwarding_with_spoofing(id, display, proto, 1611 data, 1); 1612 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); 1613 /* XXX exit_on_forward_failure */ 1614 interactive = 1; 1615 } 1616 1617 check_agent_present(); 1618 if (options.forward_agent) { 1619 debug("Requesting authentication agent forwarding."); 1620 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1621 packet_send(); 1622 } 1623 1624 /* Tell the packet module whether this is an interactive session. */ 1625 packet_set_interactive(interactive, 1626 options.ip_qos_interactive, options.ip_qos_bulk); 1627 1628 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1629 NULL, fileno(stdin), &command, environ); 1630} 1631 1632/* open new channel for a session */ 1633static int 1634ssh_session2_open(void) 1635{ 1636 Channel *c; 1637 int window, packetmax, in, out, err; 1638 1639 if (stdin_null_flag) { 1640 in = open(_PATH_DEVNULL, O_RDONLY); 1641 } else { 1642 in = dup(STDIN_FILENO); 1643 } 1644 out = dup(STDOUT_FILENO); 1645 err = dup(STDERR_FILENO); 1646 1647 if (in < 0 || out < 0 || err < 0) 1648 fatal("dup() in/out/err failed"); 1649 1650 /* enable nonblocking unless tty */ 1651 if (!isatty(in)) 1652 set_nonblock(in); 1653 if (!isatty(out)) 1654 set_nonblock(out); 1655 if (!isatty(err)) 1656 set_nonblock(err); 1657 1658 window = CHAN_SES_WINDOW_DEFAULT; 1659 packetmax = CHAN_SES_PACKET_DEFAULT; 1660 if (tty_flag) { 1661 window >>= 1; 1662 packetmax >>= 1; 1663 } 1664 c = channel_new( 1665 "session", SSH_CHANNEL_OPENING, in, out, err, 1666 window, packetmax, CHAN_EXTENDED_WRITE, 1667 "client-session", /*nonblock*/0); 1668 1669 debug3("ssh_session2_open: channel_new: %d", c->self); 1670 1671 channel_send_open(c->self); 1672 if (!no_shell_flag) 1673 channel_register_open_confirm(c->self, 1674 ssh_session2_setup, NULL); 1675 1676 return c->self; 1677} 1678 1679static int 1680ssh_session2(void) 1681{ 1682 int id = -1; 1683 1684 /* XXX should be pre-session */ 1685 if (!options.control_persist) 1686 ssh_init_stdio_forwarding(); 1687 ssh_init_forwarding(); 1688 1689 /* Start listening for multiplex clients */ 1690 muxserver_listen(); 1691 1692 /* 1693 * If we are in control persist mode and have a working mux listen 1694 * socket, then prepare to background ourselves and have a foreground 1695 * client attach as a control slave. 1696 * NB. we must save copies of the flags that we override for 1697 * the backgrounding, since we defer attachment of the slave until 1698 * after the connection is fully established (in particular, 1699 * async rfwd replies have been received for ExitOnForwardFailure). 1700 */ 1701 if (options.control_persist && muxserver_sock != -1) { 1702 ostdin_null_flag = stdin_null_flag; 1703 ono_shell_flag = no_shell_flag; 1704 orequest_tty = options.request_tty; 1705 otty_flag = tty_flag; 1706 stdin_null_flag = 1; 1707 no_shell_flag = 1; 1708 tty_flag = 0; 1709 if (!fork_after_authentication_flag) 1710 need_controlpersist_detach = 1; 1711 fork_after_authentication_flag = 1; 1712 } 1713 /* 1714 * ControlPersist mux listen socket setup failed, attempt the 1715 * stdio forward setup that we skipped earlier. 1716 */ 1717 if (options.control_persist && muxserver_sock == -1) 1718 ssh_init_stdio_forwarding(); 1719 1720 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1721 id = ssh_session2_open(); 1722 else { 1723 packet_set_interactive( 1724 options.control_master == SSHCTL_MASTER_NO, 1725 options.ip_qos_interactive, options.ip_qos_bulk); 1726 } 1727 1728 /* If we don't expect to open a new session, then disallow it */ 1729 if (options.control_master == SSHCTL_MASTER_NO && 1730 (datafellows & SSH_NEW_OPENSSH)) { 1731 debug("Requesting no-more-sessions@openssh.com"); 1732 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1733 packet_put_cstring("no-more-sessions@openssh.com"); 1734 packet_put_char(0); 1735 packet_send(); 1736 } 1737 1738 /* Execute a local command */ 1739 if (options.local_command != NULL && 1740 options.permit_local_command) 1741 ssh_local_cmd(options.local_command); 1742 1743 /* 1744 * If requested and we are not interested in replies to remote 1745 * forwarding requests, then let ssh continue in the background. 1746 */ 1747 if (fork_after_authentication_flag) { 1748 if (options.exit_on_forward_failure && 1749 options.num_remote_forwards > 0) { 1750 debug("deferring postauth fork until remote forward " 1751 "confirmation received"); 1752 } else 1753 fork_postauth(); 1754 } 1755 1756 if (options.use_roaming) 1757 request_roaming(); 1758 1759 return client_loop(tty_flag, tty_flag ? 1760 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1761} 1762 1763static void 1764load_public_identity_files(void) 1765{ 1766 char *filename, *cp, thishost[NI_MAXHOST]; 1767 char *pwdir = NULL, *pwname = NULL; 1768 int i = 0; 1769 Key *public; 1770 struct passwd *pw; 1771 u_int n_ids; 1772 char *identity_files[SSH_MAX_IDENTITY_FILES]; 1773 Key *identity_keys[SSH_MAX_IDENTITY_FILES]; 1774#ifdef ENABLE_PKCS11 1775 Key **keys; 1776 int nkeys; 1777#endif /* PKCS11 */ 1778 1779 n_ids = 0; 1780 memset(identity_files, 0, sizeof(identity_files)); 1781 memset(identity_keys, 0, sizeof(identity_keys)); 1782 1783#ifdef ENABLE_PKCS11 1784 if (options.pkcs11_provider != NULL && 1785 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1786 (pkcs11_init(!options.batch_mode) == 0) && 1787 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL, 1788 &keys)) > 0) { 1789 for (i = 0; i < nkeys; i++) { 1790 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1791 key_free(keys[i]); 1792 continue; 1793 } 1794 identity_keys[n_ids] = keys[i]; 1795 identity_files[n_ids] = 1796 xstrdup(options.pkcs11_provider); /* XXX */ 1797 n_ids++; 1798 } 1799 free(keys); 1800 } 1801#endif /* ENABLE_PKCS11 */ 1802 if ((pw = getpwuid(original_real_uid)) == NULL) 1803 fatal("load_public_identity_files: getpwuid failed"); 1804 pwname = xstrdup(pw->pw_name); 1805 pwdir = xstrdup(pw->pw_dir); 1806 if (gethostname(thishost, sizeof(thishost)) == -1) 1807 fatal("load_public_identity_files: gethostname: %s", 1808 strerror(errno)); 1809 for (i = 0; i < options.num_identity_files; i++) { 1810 if (n_ids >= SSH_MAX_IDENTITY_FILES || 1811 strcasecmp(options.identity_files[i], "none") == 0) { 1812 free(options.identity_files[i]); 1813 continue; 1814 } 1815 cp = tilde_expand_filename(options.identity_files[i], 1816 original_real_uid); 1817 filename = percent_expand(cp, "d", pwdir, 1818 "u", pwname, "l", thishost, "h", host, 1819 "r", options.user, (char *)NULL); 1820 free(cp); 1821 public = key_load_public(filename, NULL); 1822 debug("identity file %s type %d", filename, 1823 public ? public->type : -1); 1824 free(options.identity_files[i]); 1825 identity_files[n_ids] = filename; 1826 identity_keys[n_ids] = public; 1827 1828 if (++n_ids >= SSH_MAX_IDENTITY_FILES) 1829 continue; 1830 1831 /* Try to add the certificate variant too */ 1832 xasprintf(&cp, "%s-cert", filename); 1833 public = key_load_public(cp, NULL); 1834 debug("identity file %s type %d", cp, 1835 public ? public->type : -1); 1836 if (public == NULL) { 1837 free(cp); 1838 continue; 1839 } 1840 if (!key_is_cert(public)) { 1841 debug("%s: key %s type %s is not a certificate", 1842 __func__, cp, key_type(public)); 1843 key_free(public); 1844 free(cp); 1845 continue; 1846 } 1847 identity_keys[n_ids] = public; 1848 /* point to the original path, most likely the private key */ 1849 identity_files[n_ids] = xstrdup(filename); 1850 n_ids++; 1851 } 1852 options.num_identity_files = n_ids; 1853 memcpy(options.identity_files, identity_files, sizeof(identity_files)); 1854 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys)); 1855 1856 explicit_bzero(pwname, strlen(pwname)); 1857 free(pwname); 1858 explicit_bzero(pwdir, strlen(pwdir)); 1859 free(pwdir); 1860} 1861 1862static void 1863main_sigchld_handler(int sig) 1864{ 1865 int save_errno = errno; 1866 pid_t pid; 1867 int status; 1868 1869 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 1870 (pid < 0 && errno == EINTR)) 1871 ; 1872 1873 signal(sig, main_sigchld_handler); 1874 errno = save_errno; 1875} 1876