1 /* $OpenBSD: ssh.c,v 1.410 2014/11/18 20:54:28 krw 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 <sys/types.h> 44 #include <sys/ioctl.h> 45 #include <sys/param.h> 46 #include <sys/queue.h> 47 #include <sys/resource.h> 48 #include <sys/socket.h> 49 #include <sys/stat.h> 50 #include <sys/time.h> 51 #include <sys/wait.h> 52 53 #include <ctype.h> 54 #include <errno.h> 55 #include <fcntl.h> 56 #include <netdb.h> 57 #include <paths.h> 58 #include <pwd.h> 59 #include <signal.h> 60 #include <stddef.h> 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <string.h> 64 #include <unistd.h> 65 66 #ifdef WITH_OPENSSL 67 #include <openssl/evp.h> 68 #include <openssl/err.h> 69 #endif 70 71 #include "xmalloc.h" 72 #include "ssh.h" 73 #include "ssh1.h" 74 #include "ssh2.h" 75 #include "canohost.h" 76 #include "compat.h" 77 #include "cipher.h" 78 #include "digest.h" 79 #include "packet.h" 80 #include "buffer.h" 81 #include "channels.h" 82 #include "key.h" 83 #include "authfd.h" 84 #include "authfile.h" 85 #include "pathnames.h" 86 #include "dispatch.h" 87 #include "clientloop.h" 88 #include "log.h" 89 #include "misc.h" 90 #include "readconf.h" 91 #include "sshconnect.h" 92 #include "kex.h" 93 #include "mac.h" 94 #include "sshpty.h" 95 #include "match.h" 96 #include "msg.h" 97 #include "uidswap.h" 98 #include "roaming.h" 99 #include "version.h" 100 101 #ifdef ENABLE_PKCS11 102 #include "ssh-pkcs11.h" 103 #endif 104 105 extern char *__progname; 106 107 /* Flag indicating whether debug mode is on. May be set on the command line. */ 108 int debug_flag = 0; 109 110 /* Flag indicating whether a tty should be requested */ 111 int tty_flag = 0; 112 113 /* don't exec a shell */ 114 int no_shell_flag = 0; 115 116 /* 117 * Flag indicating that nothing should be read from stdin. This can be set 118 * on the command line. 119 */ 120 int stdin_null_flag = 0; 121 122 /* 123 * Flag indicating that the current process should be backgrounded and 124 * a new slave launched in the foreground for ControlPersist. 125 */ 126 int need_controlpersist_detach = 0; 127 128 /* Copies of flags for ControlPersist foreground slave */ 129 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty; 130 131 /* 132 * Flag indicating that ssh should fork after authentication. This is useful 133 * so that the passphrase can be entered manually, and then ssh goes to the 134 * background. 135 */ 136 int fork_after_authentication_flag = 0; 137 138 /* forward stdio to remote host and port */ 139 char *stdio_forward_host = NULL; 140 int stdio_forward_port = 0; 141 142 /* 143 * General data structure for command line options and options configurable 144 * in configuration files. See readconf.h. 145 */ 146 Options options; 147 148 /* optional user configfile */ 149 char *config = NULL; 150 151 /* 152 * Name of the host we are connecting to. This is the name given on the 153 * command line, or the HostName specified for the user-supplied name in a 154 * configuration file. 155 */ 156 char *host; 157 158 /* socket address the host resolves to */ 159 struct sockaddr_storage hostaddr; 160 161 /* Private host keys. */ 162 Sensitive sensitive_data; 163 164 /* Original real UID. */ 165 uid_t original_real_uid; 166 uid_t original_effective_uid; 167 168 /* command to be executed */ 169 Buffer command; 170 171 /* Should we execute a command or invoke a subsystem? */ 172 int subsystem_flag = 0; 173 174 /* # of replies received for global requests */ 175 static int remote_forward_confirms_received = 0; 176 177 /* mux.c */ 178 extern int muxserver_sock; 179 extern u_int muxclient_command; 180 181 /* Prints a help message to the user. This function never returns. */ 182 183 static void 184 usage(void) 185 { 186 fprintf(stderr, 187 "usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" 188 " [-D [bind_address:]port] [-E log_file] [-e escape_char]\n" 189 " [-F configfile] [-I pkcs11] [-i identity_file]\n" 190 " [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec]\n" 191 " [-O ctl_cmd] [-o option] [-p port]\n" 192 " [-Q cipher | cipher-auth | mac | kex | key]\n" 193 " [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port]\n" 194 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n" 195 ); 196 exit(255); 197 } 198 199 static int ssh_session(void); 200 static int ssh_session2(void); 201 static void load_public_identity_files(void); 202 static void main_sigchld_handler(int); 203 204 /* from muxclient.c */ 205 void muxclient(const char *); 206 void muxserver_listen(void); 207 208 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */ 209 static void 210 tilde_expand_paths(char **paths, u_int num_paths) 211 { 212 u_int i; 213 char *cp; 214 215 for (i = 0; i < num_paths; i++) { 216 cp = tilde_expand_filename(paths[i], original_real_uid); 217 free(paths[i]); 218 paths[i] = cp; 219 } 220 } 221 222 /* 223 * Attempt to resolve a host name / port to a set of addresses and 224 * optionally return any CNAMEs encountered along the way. 225 * Returns NULL on failure. 226 * NB. this function must operate with a options having undefined members. 227 */ 228 static struct addrinfo * 229 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen) 230 { 231 char strport[NI_MAXSERV]; 232 struct addrinfo hints, *res; 233 int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1; 234 235 if (port <= 0) 236 port = default_ssh_port(); 237 238 snprintf(strport, sizeof strport, "%u", port); 239 memset(&hints, 0, sizeof(hints)); 240 hints.ai_family = options.address_family == -1 ? 241 AF_UNSPEC : options.address_family; 242 hints.ai_socktype = SOCK_STREAM; 243 if (cname != NULL) 244 hints.ai_flags = AI_CANONNAME; 245 if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) { 246 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA)) 247 loglevel = SYSLOG_LEVEL_ERROR; 248 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s", 249 __progname, name, ssh_gai_strerror(gaierr)); 250 return NULL; 251 } 252 if (cname != NULL && res->ai_canonname != NULL) { 253 if (strlcpy(cname, res->ai_canonname, clen) >= clen) { 254 error("%s: host \"%s\" cname \"%s\" too long (max %lu)", 255 __func__, name, res->ai_canonname, (u_long)clen); 256 if (clen > 0) 257 *cname = '\0'; 258 } 259 } 260 return res; 261 } 262 263 /* 264 * Check whether the cname is a permitted replacement for the hostname 265 * and perform the replacement if it is. 266 * NB. this function must operate with a options having undefined members. 267 */ 268 static int 269 check_follow_cname(char **namep, const char *cname) 270 { 271 int i; 272 struct allowed_cname *rule; 273 274 if (*cname == '\0' || options.num_permitted_cnames == 0 || 275 strcmp(*namep, cname) == 0) 276 return 0; 277 if (options.canonicalize_hostname == SSH_CANONICALISE_NO) 278 return 0; 279 /* 280 * Don't attempt to canonicalize names that will be interpreted by 281 * a proxy unless the user specifically requests so. 282 */ 283 if (!option_clear_or_none(options.proxy_command) && 284 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS) 285 return 0; 286 debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname); 287 for (i = 0; i < options.num_permitted_cnames; i++) { 288 rule = options.permitted_cnames + i; 289 if (match_pattern_list(*namep, rule->source_list, 290 strlen(rule->source_list), 1) != 1 || 291 match_pattern_list(cname, rule->target_list, 292 strlen(rule->target_list), 1) != 1) 293 continue; 294 verbose("Canonicalized DNS aliased hostname " 295 "\"%s\" => \"%s\"", *namep, cname); 296 free(*namep); 297 *namep = xstrdup(cname); 298 return 1; 299 } 300 return 0; 301 } 302 303 /* 304 * Attempt to resolve the supplied hostname after applying the user's 305 * canonicalization rules. Returns the address list for the host or NULL 306 * if no name was found after canonicalization. 307 * NB. this function must operate with a options having undefined members. 308 */ 309 static struct addrinfo * 310 resolve_canonicalize(char **hostp, int port) 311 { 312 int i, ndots; 313 char *cp, *fullhost, cname_target[NI_MAXHOST]; 314 struct addrinfo *addrs; 315 316 if (options.canonicalize_hostname == SSH_CANONICALISE_NO) 317 return NULL; 318 319 /* 320 * Don't attempt to canonicalize names that will be interpreted by 321 * a proxy unless the user specifically requests so. 322 */ 323 if (!option_clear_or_none(options.proxy_command) && 324 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS) 325 return NULL; 326 327 /* Don't apply canonicalization to sufficiently-qualified hostnames */ 328 ndots = 0; 329 for (cp = *hostp; *cp != '\0'; cp++) { 330 if (*cp == '.') 331 ndots++; 332 } 333 if (ndots > options.canonicalize_max_dots) { 334 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)", 335 __func__, *hostp, options.canonicalize_max_dots); 336 return NULL; 337 } 338 /* Attempt each supplied suffix */ 339 for (i = 0; i < options.num_canonical_domains; i++) { 340 *cname_target = '\0'; 341 xasprintf(&fullhost, "%s.%s.", *hostp, 342 options.canonical_domains[i]); 343 debug3("%s: attempting \"%s\" => \"%s\"", __func__, 344 *hostp, fullhost); 345 if ((addrs = resolve_host(fullhost, port, 0, 346 cname_target, sizeof(cname_target))) == NULL) { 347 free(fullhost); 348 continue; 349 } 350 /* Remove trailing '.' */ 351 fullhost[strlen(fullhost) - 1] = '\0'; 352 /* Follow CNAME if requested */ 353 if (!check_follow_cname(&fullhost, cname_target)) { 354 debug("Canonicalized hostname \"%s\" => \"%s\"", 355 *hostp, fullhost); 356 } 357 free(*hostp); 358 *hostp = fullhost; 359 return addrs; 360 } 361 if (!options.canonicalize_fallback_local) 362 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp); 363 debug2("%s: host %s not found in any suffix", __func__, *hostp); 364 return NULL; 365 } 366 367 /* 368 * Read per-user configuration file. Ignore the system wide config 369 * file if the user specifies a config file on the command line. 370 */ 371 static void 372 process_config_files(const char *host_arg, struct passwd *pw, int post_canon) 373 { 374 char buf[MAXPATHLEN]; 375 int r; 376 377 if (config != NULL) { 378 if (strcasecmp(config, "none") != 0 && 379 !read_config_file(config, pw, host, host_arg, &options, 380 SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 0))) 381 fatal("Can't open user config file %.100s: " 382 "%.100s", config, strerror(errno)); 383 } else { 384 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, 385 _PATH_SSH_USER_CONFFILE); 386 if (r > 0 && (size_t)r < sizeof(buf)) 387 (void)read_config_file(buf, pw, host, host_arg, 388 &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF | 389 (post_canon ? SSHCONF_POSTCANON : 0)); 390 391 /* Read systemwide configuration file after user config. */ 392 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, 393 host, host_arg, &options, 394 post_canon ? SSHCONF_POSTCANON : 0); 395 } 396 } 397 398 /* Rewrite the port number in an addrinfo list of addresses */ 399 static void 400 set_addrinfo_port(struct addrinfo *addrs, int port) 401 { 402 struct addrinfo *addr; 403 404 for (addr = addrs; addr != NULL; addr = addr->ai_next) { 405 switch (addr->ai_family) { 406 case AF_INET: 407 ((struct sockaddr_in *)addr->ai_addr)-> 408 sin_port = htons(port); 409 break; 410 case AF_INET6: 411 ((struct sockaddr_in6 *)addr->ai_addr)-> 412 sin6_port = htons(port); 413 break; 414 } 415 } 416 } 417 418 /* 419 * Main program for the ssh client. 420 */ 421 int 422 main(int ac, char **av) 423 { 424 int i, r, opt, exit_status, use_syslog, config_test = 0; 425 char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg, *logfile; 426 char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV]; 427 char cname[NI_MAXHOST]; 428 struct stat st; 429 struct passwd *pw; 430 int timeout_ms; 431 extern int optind, optreset; 432 extern char *optarg; 433 struct Forward fwd; 434 struct addrinfo *addrs = NULL; 435 struct ssh_digest_ctx *md; 436 u_char conn_hash[SSH_DIGEST_MAX_LENGTH]; 437 char *conn_hash_hex; 438 439 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 440 sanitise_stdfd(); 441 442 /* 443 * Discard other fds that are hanging around. These can cause problem 444 * with backgrounded ssh processes started by ControlPersist. 445 */ 446 closefrom(STDERR_FILENO + 1); 447 448 /* 449 * Save the original real uid. It will be needed later (uid-swapping 450 * may clobber the real uid). 451 */ 452 original_real_uid = getuid(); 453 original_effective_uid = geteuid(); 454 455 /* 456 * Use uid-swapping to give up root privileges for the duration of 457 * option processing. We will re-instantiate the rights when we are 458 * ready to create the privileged port, and will permanently drop 459 * them when the port has been created (actually, when the connection 460 * has been made, as we may need to create the port several times). 461 */ 462 PRIV_END; 463 464 /* If we are installed setuid root be careful to not drop core. */ 465 if (original_real_uid != original_effective_uid) { 466 struct rlimit rlim; 467 rlim.rlim_cur = rlim.rlim_max = 0; 468 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 469 fatal("setrlimit failed: %.100s", strerror(errno)); 470 } 471 /* Get user data. */ 472 pw = getpwuid(original_real_uid); 473 if (!pw) { 474 logit("No user exists for uid %lu", (u_long)original_real_uid); 475 exit(255); 476 } 477 /* Take a copy of the returned structure. */ 478 pw = pwcopy(pw); 479 480 /* 481 * Set our umask to something reasonable, as some files are created 482 * with the default umask. This will make them world-readable but 483 * writable only by the owner, which is ok for all files for which we 484 * don't set the modes explicitly. 485 */ 486 umask(022); 487 488 /* 489 * Initialize option structure to indicate that no values have been 490 * set. 491 */ 492 initialize_options(&options); 493 494 /* Parse command-line arguments. */ 495 host = NULL; 496 use_syslog = 0; 497 logfile = NULL; 498 argv0 = av[0]; 499 500 again: 501 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 502 "ACD:E:F:GI:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) { 503 switch (opt) { 504 case '1': 505 options.protocol = SSH_PROTO_1; 506 break; 507 case '2': 508 options.protocol = SSH_PROTO_2; 509 break; 510 case '4': 511 options.address_family = AF_INET; 512 break; 513 case '6': 514 options.address_family = AF_INET6; 515 break; 516 case 'n': 517 stdin_null_flag = 1; 518 break; 519 case 'f': 520 fork_after_authentication_flag = 1; 521 stdin_null_flag = 1; 522 break; 523 case 'x': 524 options.forward_x11 = 0; 525 break; 526 case 'X': 527 options.forward_x11 = 1; 528 break; 529 case 'y': 530 use_syslog = 1; 531 break; 532 case 'E': 533 logfile = xstrdup(optarg); 534 break; 535 case 'G': 536 config_test = 1; 537 break; 538 case 'Y': 539 options.forward_x11 = 1; 540 options.forward_x11_trusted = 1; 541 break; 542 case 'g': 543 options.fwd_opts.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 fprintf(stderr, "%s, %s\n", 635 SSH_VERSION, 636 #ifdef WITH_OPENSSL 637 SSLeay_version(SSLEAY_VERSION) 638 #else 639 "without OpenSSL" 640 #endif 641 ); 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, 787 host ? host : "", host ? host : "", line, 788 "command-line", 0, NULL, SSHCONF_USERCONF) != 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 #ifdef WITH_OPENSSL 839 OpenSSL_add_all_algorithms(); 840 ERR_load_crypto_strings(); 841 #endif 842 843 /* Initialize the command to execute on remote host. */ 844 buffer_init(&command); 845 846 /* 847 * Save the command to execute on the remote host in a buffer. There 848 * is no limit on the length of the command, except by the maximum 849 * packet size. Also sets the tty flag if there is no command. 850 */ 851 if (!ac) { 852 /* No command specified - execute shell on a tty. */ 853 if (subsystem_flag) { 854 fprintf(stderr, 855 "You must specify a subsystem to invoke.\n"); 856 usage(); 857 } 858 } else { 859 /* A command has been specified. Store it into the buffer. */ 860 for (i = 0; i < ac; i++) { 861 if (i) 862 buffer_append(&command, " ", 1); 863 buffer_append(&command, av[i], strlen(av[i])); 864 } 865 } 866 867 /* Cannot fork to background if no command. */ 868 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 869 !no_shell_flag) 870 fatal("Cannot fork into background without a command " 871 "to execute."); 872 873 /* 874 * Initialize "log" output. Since we are the client all output 875 * goes to stderr unless otherwise specified by -y or -E. 876 */ 877 if (use_syslog && logfile != NULL) 878 fatal("Can't specify both -y and -E"); 879 if (logfile != NULL) { 880 log_redirect_stderr_to(logfile); 881 free(logfile); 882 } 883 log_init(argv0, 884 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 885 SYSLOG_FACILITY_USER, !use_syslog); 886 887 if (debug_flag) 888 logit("%s, %s", SSH_VERSION, 889 #ifdef WITH_OPENSSL 890 SSLeay_version(SSLEAY_VERSION) 891 #else 892 "without OpenSSL" 893 #endif 894 ); 895 896 /* Parse the configuration files */ 897 process_config_files(host_arg, pw, 0); 898 899 /* Hostname canonicalisation needs a few options filled. */ 900 fill_default_options_for_canonicalization(&options); 901 902 /* If the user has replaced the hostname then take it into use now */ 903 if (options.hostname != NULL) { 904 /* NB. Please keep in sync with readconf.c:match_cfg_line() */ 905 cp = percent_expand(options.hostname, 906 "h", host, (char *)NULL); 907 free(host); 908 host = cp; 909 free(options.hostname); 910 options.hostname = xstrdup(host); 911 } 912 913 /* If canonicalization requested then try to apply it */ 914 lowercase(host); 915 if (options.canonicalize_hostname != SSH_CANONICALISE_NO) 916 addrs = resolve_canonicalize(&host, options.port); 917 918 /* 919 * If CanonicalizePermittedCNAMEs have been specified but 920 * other canonicalization did not happen (by not being requested 921 * or by failing with fallback) then the hostname may still be changed 922 * as a result of CNAME following. 923 * 924 * Try to resolve the bare hostname name using the system resolver's 925 * usual search rules and then apply the CNAME follow rules. 926 * 927 * Skip the lookup if a ProxyCommand is being used unless the user 928 * has specifically requested canonicalisation for this case via 929 * CanonicalizeHostname=always 930 */ 931 if (addrs == NULL && options.num_permitted_cnames != 0 && 932 (option_clear_or_none(options.proxy_command) || 933 options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) { 934 if ((addrs = resolve_host(host, options.port, 935 option_clear_or_none(options.proxy_command), 936 cname, sizeof(cname))) == NULL) { 937 /* Don't fatal proxied host names not in the DNS */ 938 if (option_clear_or_none(options.proxy_command)) 939 cleanup_exit(255); /* logged in resolve_host */ 940 } else 941 check_follow_cname(&host, cname); 942 } 943 944 /* 945 * If canonicalisation is enabled then re-parse the configuration 946 * files as new stanzas may match. 947 */ 948 if (options.canonicalize_hostname != 0) { 949 debug("Re-reading configuration after hostname " 950 "canonicalisation"); 951 free(options.hostname); 952 options.hostname = xstrdup(host); 953 process_config_files(host_arg, pw, 1); 954 /* 955 * Address resolution happens early with canonicalisation 956 * enabled and the port number may have changed since, so 957 * reset it in address list 958 */ 959 if (addrs != NULL && options.port > 0) 960 set_addrinfo_port(addrs, options.port); 961 } 962 963 /* Fill configuration defaults. */ 964 fill_default_options(&options); 965 966 if (options.port == 0) 967 options.port = default_ssh_port(); 968 channel_set_af(options.address_family); 969 970 /* Tidy and check options */ 971 if (options.host_key_alias != NULL) 972 lowercase(options.host_key_alias); 973 if (options.proxy_command != NULL && 974 strcmp(options.proxy_command, "-") == 0 && 975 options.proxy_use_fdpass) 976 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible"); 977 if (original_effective_uid != 0) 978 options.use_privileged_port = 0; 979 980 /* reinit */ 981 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 982 983 if (options.request_tty == REQUEST_TTY_YES || 984 options.request_tty == REQUEST_TTY_FORCE) 985 tty_flag = 1; 986 987 /* Allocate a tty by default if no command specified. */ 988 if (buffer_len(&command) == 0) 989 tty_flag = options.request_tty != REQUEST_TTY_NO; 990 991 /* Force no tty */ 992 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0) 993 tty_flag = 0; 994 /* Do not allocate a tty if stdin is not a tty. */ 995 if ((!isatty(fileno(stdin)) || stdin_null_flag) && 996 options.request_tty != REQUEST_TTY_FORCE) { 997 if (tty_flag) 998 logit("Pseudo-terminal will not be allocated because " 999 "stdin is not a terminal."); 1000 tty_flag = 0; 1001 } 1002 1003 if (options.user == NULL) 1004 options.user = xstrdup(pw->pw_name); 1005 1006 if (gethostname(thishost, sizeof(thishost)) == -1) 1007 fatal("gethostname: %s", strerror(errno)); 1008 strlcpy(shorthost, thishost, sizeof(shorthost)); 1009 shorthost[strcspn(thishost, ".")] = '\0'; 1010 snprintf(portstr, sizeof(portstr), "%d", options.port); 1011 1012 if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL || 1013 ssh_digest_update(md, thishost, strlen(thishost)) < 0 || 1014 ssh_digest_update(md, host, strlen(host)) < 0 || 1015 ssh_digest_update(md, portstr, strlen(portstr)) < 0 || 1016 ssh_digest_update(md, options.user, strlen(options.user)) < 0 || 1017 ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0) 1018 fatal("%s: mux digest failed", __func__); 1019 ssh_digest_free(md); 1020 conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1)); 1021 1022 if (options.local_command != NULL) { 1023 debug3("expanding LocalCommand: %s", options.local_command); 1024 cp = options.local_command; 1025 options.local_command = percent_expand(cp, 1026 "C", conn_hash_hex, 1027 "L", shorthost, 1028 "d", pw->pw_dir, 1029 "h", host, 1030 "l", thishost, 1031 "n", host_arg, 1032 "p", portstr, 1033 "r", options.user, 1034 "u", pw->pw_name, 1035 (char *)NULL); 1036 debug3("expanded LocalCommand: %s", options.local_command); 1037 free(cp); 1038 } 1039 1040 if (options.control_path != NULL) { 1041 cp = tilde_expand_filename(options.control_path, 1042 original_real_uid); 1043 free(options.control_path); 1044 options.control_path = percent_expand(cp, 1045 "C", conn_hash_hex, 1046 "L", shorthost, 1047 "h", host, 1048 "l", thishost, 1049 "n", host_arg, 1050 "p", portstr, 1051 "r", options.user, 1052 "u", pw->pw_name, 1053 (char *)NULL); 1054 free(cp); 1055 } 1056 free(conn_hash_hex); 1057 1058 if (config_test) { 1059 dump_client_config(&options, host); 1060 exit(0); 1061 } 1062 1063 if (muxclient_command != 0 && options.control_path == NULL) 1064 fatal("No ControlPath specified for \"-O\" command"); 1065 if (options.control_path != NULL) 1066 muxclient(options.control_path); 1067 1068 /* 1069 * If hostname canonicalisation was not enabled, then we may not 1070 * have yet resolved the hostname. Do so now. 1071 */ 1072 if (addrs == NULL && options.proxy_command == NULL) { 1073 if ((addrs = resolve_host(host, options.port, 1, 1074 cname, sizeof(cname))) == NULL) 1075 cleanup_exit(255); /* resolve_host logs the error */ 1076 } 1077 1078 timeout_ms = options.connection_timeout * 1000; 1079 1080 /* Open a connection to the remote host. */ 1081 if (ssh_connect(host, addrs, &hostaddr, options.port, 1082 options.address_family, options.connection_attempts, 1083 &timeout_ms, options.tcp_keep_alive, 1084 options.use_privileged_port) != 0) 1085 exit(255); 1086 1087 if (addrs != NULL) 1088 freeaddrinfo(addrs); 1089 1090 packet_set_timeout(options.server_alive_interval, 1091 options.server_alive_count_max); 1092 1093 if (timeout_ms > 0) 1094 debug3("timeout: %d ms remain after connect", timeout_ms); 1095 1096 /* 1097 * If we successfully made the connection, load the host private key 1098 * in case we will need it later for combined rsa-rhosts 1099 * authentication. This must be done before releasing extra 1100 * privileges, because the file is only readable by root. 1101 * If we cannot access the private keys, load the public keys 1102 * instead and try to execute the ssh-keysign helper instead. 1103 */ 1104 sensitive_data.nkeys = 0; 1105 sensitive_data.keys = NULL; 1106 sensitive_data.external_keysign = 0; 1107 if (options.rhosts_rsa_authentication || 1108 options.hostbased_authentication) { 1109 sensitive_data.nkeys = 9; 1110 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 1111 sizeof(Key)); 1112 1113 PRIV_START; 1114 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 1115 _PATH_HOST_KEY_FILE, "", NULL, NULL); 1116 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA, 1117 _PATH_HOST_DSA_KEY_FILE, "", NULL); 1118 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA, 1119 _PATH_HOST_ECDSA_KEY_FILE, "", NULL); 1120 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA, 1121 _PATH_HOST_RSA_KEY_FILE, "", NULL); 1122 sensitive_data.keys[4] = key_load_private_cert(KEY_ED25519, 1123 _PATH_HOST_ED25519_KEY_FILE, "", NULL); 1124 sensitive_data.keys[5] = key_load_private_type(KEY_DSA, 1125 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 1126 sensitive_data.keys[6] = key_load_private_type(KEY_ECDSA, 1127 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL); 1128 sensitive_data.keys[7] = key_load_private_type(KEY_RSA, 1129 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 1130 sensitive_data.keys[8] = key_load_private_type(KEY_ED25519, 1131 _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL); 1132 PRIV_END; 1133 1134 if (options.hostbased_authentication == 1 && 1135 sensitive_data.keys[0] == NULL && 1136 sensitive_data.keys[5] == NULL && 1137 sensitive_data.keys[6] == NULL && 1138 sensitive_data.keys[7] == NULL && 1139 sensitive_data.keys[8] == NULL) { 1140 sensitive_data.keys[1] = key_load_cert( 1141 _PATH_HOST_DSA_KEY_FILE); 1142 sensitive_data.keys[2] = key_load_cert( 1143 _PATH_HOST_ECDSA_KEY_FILE); 1144 sensitive_data.keys[3] = key_load_cert( 1145 _PATH_HOST_RSA_KEY_FILE); 1146 sensitive_data.keys[4] = key_load_cert( 1147 _PATH_HOST_ED25519_KEY_FILE); 1148 sensitive_data.keys[5] = key_load_public( 1149 _PATH_HOST_DSA_KEY_FILE, NULL); 1150 sensitive_data.keys[6] = key_load_public( 1151 _PATH_HOST_ECDSA_KEY_FILE, NULL); 1152 sensitive_data.keys[7] = key_load_public( 1153 _PATH_HOST_RSA_KEY_FILE, NULL); 1154 sensitive_data.keys[8] = key_load_public( 1155 _PATH_HOST_ED25519_KEY_FILE, NULL); 1156 sensitive_data.external_keysign = 1; 1157 } 1158 } 1159 /* 1160 * Get rid of any extra privileges that we may have. We will no 1161 * longer need them. Also, extra privileges could make it very hard 1162 * to read identity files and other non-world-readable files from the 1163 * user's home directory if it happens to be on a NFS volume where 1164 * root is mapped to nobody. 1165 */ 1166 if (original_effective_uid == 0) { 1167 PRIV_START; 1168 permanently_set_uid(pw); 1169 } 1170 1171 /* 1172 * Now that we are back to our own permissions, create ~/.ssh 1173 * directory if it doesn't already exist. 1174 */ 1175 if (config == NULL) { 1176 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 1177 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 1178 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) 1179 if (mkdir(buf, 0700) < 0) 1180 error("Could not create directory '%.200s'.", 1181 buf); 1182 } 1183 1184 /* load options.identity_files */ 1185 load_public_identity_files(); 1186 1187 /* Expand ~ in known host file names. */ 1188 tilde_expand_paths(options.system_hostfiles, 1189 options.num_system_hostfiles); 1190 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles); 1191 1192 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 1193 signal(SIGCHLD, main_sigchld_handler); 1194 1195 /* Log into the remote system. Never returns if the login fails. */ 1196 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 1197 options.port, pw, timeout_ms); 1198 1199 if (packet_connection_is_on_socket()) { 1200 verbose("Authenticated to %s ([%s]:%d).", host, 1201 get_remote_ipaddr(), get_remote_port()); 1202 } else { 1203 verbose("Authenticated to %s (via proxy).", host); 1204 } 1205 1206 /* We no longer need the private host keys. Clear them now. */ 1207 if (sensitive_data.nkeys != 0) { 1208 for (i = 0; i < sensitive_data.nkeys; i++) { 1209 if (sensitive_data.keys[i] != NULL) { 1210 /* Destroys contents safely */ 1211 debug3("clear hostkey %d", i); 1212 key_free(sensitive_data.keys[i]); 1213 sensitive_data.keys[i] = NULL; 1214 } 1215 } 1216 free(sensitive_data.keys); 1217 } 1218 for (i = 0; i < options.num_identity_files; i++) { 1219 free(options.identity_files[i]); 1220 options.identity_files[i] = NULL; 1221 if (options.identity_keys[i]) { 1222 key_free(options.identity_keys[i]); 1223 options.identity_keys[i] = NULL; 1224 } 1225 } 1226 1227 exit_status = compat20 ? ssh_session2() : ssh_session(); 1228 packet_close(); 1229 1230 if (options.control_path != NULL && muxserver_sock != -1) 1231 unlink(options.control_path); 1232 1233 /* Kill ProxyCommand if it is running. */ 1234 ssh_kill_proxy_command(); 1235 1236 return exit_status; 1237 } 1238 1239 static void 1240 control_persist_detach(void) 1241 { 1242 pid_t pid; 1243 int devnull; 1244 1245 debug("%s: backgrounding master process", __func__); 1246 1247 /* 1248 * master (current process) into the background, and make the 1249 * foreground process a client of the backgrounded master. 1250 */ 1251 switch ((pid = fork())) { 1252 case -1: 1253 fatal("%s: fork: %s", __func__, strerror(errno)); 1254 case 0: 1255 /* Child: master process continues mainloop */ 1256 break; 1257 default: 1258 /* Parent: set up mux slave to connect to backgrounded master */ 1259 debug2("%s: background process is %ld", __func__, (long)pid); 1260 stdin_null_flag = ostdin_null_flag; 1261 options.request_tty = orequest_tty; 1262 tty_flag = otty_flag; 1263 close(muxserver_sock); 1264 muxserver_sock = -1; 1265 options.control_master = SSHCTL_MASTER_NO; 1266 muxclient(options.control_path); 1267 /* muxclient() doesn't return on success. */ 1268 fatal("Failed to connect to new control master"); 1269 } 1270 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { 1271 error("%s: open(\"/dev/null\"): %s", __func__, 1272 strerror(errno)); 1273 } else { 1274 if (dup2(devnull, STDIN_FILENO) == -1 || 1275 dup2(devnull, STDOUT_FILENO) == -1) 1276 error("%s: dup2: %s", __func__, strerror(errno)); 1277 if (devnull > STDERR_FILENO) 1278 close(devnull); 1279 } 1280 daemon(1, 1); 1281 setproctitle("%s [mux]", options.control_path); 1282 } 1283 1284 /* Do fork() after authentication. Used by "ssh -f" */ 1285 static void 1286 fork_postauth(void) 1287 { 1288 if (need_controlpersist_detach) 1289 control_persist_detach(); 1290 debug("forking to background"); 1291 fork_after_authentication_flag = 0; 1292 if (daemon(1, 1) < 0) 1293 fatal("daemon() failed: %.200s", strerror(errno)); 1294 } 1295 1296 /* Callback for remote forward global requests */ 1297 static void 1298 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 1299 { 1300 struct Forward *rfwd = (struct Forward *)ctxt; 1301 1302 /* XXX verbose() on failure? */ 1303 debug("remote forward %s for: listen %s%s%d, connect %s:%d", 1304 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 1305 rfwd->listen_path ? rfwd->listen_path : 1306 rfwd->listen_host ? rfwd->listen_host : "", 1307 (rfwd->listen_path || rfwd->listen_host) ? ":" : "", 1308 rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path : 1309 rfwd->connect_host, rfwd->connect_port); 1310 if (rfwd->listen_path == NULL && rfwd->listen_port == 0) { 1311 if (type == SSH2_MSG_REQUEST_SUCCESS) { 1312 rfwd->allocated_port = packet_get_int(); 1313 logit("Allocated port %u for remote forward to %s:%d", 1314 rfwd->allocated_port, 1315 rfwd->connect_host, rfwd->connect_port); 1316 channel_update_permitted_opens(rfwd->handle, 1317 rfwd->allocated_port); 1318 } else { 1319 channel_update_permitted_opens(rfwd->handle, -1); 1320 } 1321 } 1322 1323 if (type == SSH2_MSG_REQUEST_FAILURE) { 1324 if (options.exit_on_forward_failure) { 1325 if (rfwd->listen_path != NULL) 1326 fatal("Error: remote port forwarding failed " 1327 "for listen path %s", rfwd->listen_path); 1328 else 1329 fatal("Error: remote port forwarding failed " 1330 "for listen port %d", rfwd->listen_port); 1331 } else { 1332 if (rfwd->listen_path != NULL) 1333 logit("Warning: remote port forwarding failed " 1334 "for listen path %s", rfwd->listen_path); 1335 else 1336 logit("Warning: remote port forwarding failed " 1337 "for listen port %d", rfwd->listen_port); 1338 } 1339 } 1340 if (++remote_forward_confirms_received == options.num_remote_forwards) { 1341 debug("All remote forwarding requests processed"); 1342 if (fork_after_authentication_flag) 1343 fork_postauth(); 1344 } 1345 } 1346 1347 static void 1348 client_cleanup_stdio_fwd(int id, void *arg) 1349 { 1350 debug("stdio forwarding: done"); 1351 cleanup_exit(0); 1352 } 1353 1354 static void 1355 ssh_stdio_confirm(int id, int success, void *arg) 1356 { 1357 if (!success) 1358 fatal("stdio forwarding failed"); 1359 } 1360 1361 static void 1362 ssh_init_stdio_forwarding(void) 1363 { 1364 Channel *c; 1365 int in, out; 1366 1367 if (stdio_forward_host == NULL) 1368 return; 1369 if (!compat20) 1370 fatal("stdio forwarding require Protocol 2"); 1371 1372 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port); 1373 1374 if ((in = dup(STDIN_FILENO)) < 0 || 1375 (out = dup(STDOUT_FILENO)) < 0) 1376 fatal("channel_connect_stdio_fwd: dup() in/out failed"); 1377 if ((c = channel_connect_stdio_fwd(stdio_forward_host, 1378 stdio_forward_port, in, out)) == NULL) 1379 fatal("%s: channel_connect_stdio_fwd failed", __func__); 1380 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0); 1381 channel_register_open_confirm(c->self, ssh_stdio_confirm, NULL); 1382 } 1383 1384 static void 1385 ssh_init_forwarding(void) 1386 { 1387 int success = 0; 1388 int i; 1389 1390 /* Initiate local TCP/IP port forwardings. */ 1391 for (i = 0; i < options.num_local_forwards; i++) { 1392 debug("Local connections to %.200s:%d forwarded to remote " 1393 "address %.200s:%d", 1394 (options.local_forwards[i].listen_path != NULL) ? 1395 options.local_forwards[i].listen_path : 1396 (options.local_forwards[i].listen_host == NULL) ? 1397 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") : 1398 options.local_forwards[i].listen_host, 1399 options.local_forwards[i].listen_port, 1400 (options.local_forwards[i].connect_path != NULL) ? 1401 options.local_forwards[i].connect_path : 1402 options.local_forwards[i].connect_host, 1403 options.local_forwards[i].connect_port); 1404 success += channel_setup_local_fwd_listener( 1405 &options.local_forwards[i], &options.fwd_opts); 1406 } 1407 if (i > 0 && success != i && options.exit_on_forward_failure) 1408 fatal("Could not request local forwarding."); 1409 if (i > 0 && success == 0) 1410 error("Could not request local forwarding."); 1411 1412 /* Initiate remote TCP/IP port forwardings. */ 1413 for (i = 0; i < options.num_remote_forwards; i++) { 1414 debug("Remote connections from %.200s:%d forwarded to " 1415 "local address %.200s:%d", 1416 (options.remote_forwards[i].listen_path != NULL) ? 1417 options.remote_forwards[i].listen_path : 1418 (options.remote_forwards[i].listen_host == NULL) ? 1419 "LOCALHOST" : options.remote_forwards[i].listen_host, 1420 options.remote_forwards[i].listen_port, 1421 (options.remote_forwards[i].connect_path != NULL) ? 1422 options.remote_forwards[i].connect_path : 1423 options.remote_forwards[i].connect_host, 1424 options.remote_forwards[i].connect_port); 1425 options.remote_forwards[i].handle = 1426 channel_request_remote_forwarding( 1427 &options.remote_forwards[i]); 1428 if (options.remote_forwards[i].handle < 0) { 1429 if (options.exit_on_forward_failure) 1430 fatal("Could not request remote forwarding."); 1431 else 1432 logit("Warning: Could not request remote " 1433 "forwarding."); 1434 } else { 1435 client_register_global_confirm(ssh_confirm_remote_forward, 1436 &options.remote_forwards[i]); 1437 } 1438 } 1439 1440 /* Initiate tunnel forwarding. */ 1441 if (options.tun_open != SSH_TUNMODE_NO) { 1442 if (client_request_tun_fwd(options.tun_open, 1443 options.tun_local, options.tun_remote) == -1) { 1444 if (options.exit_on_forward_failure) 1445 fatal("Could not request tunnel forwarding."); 1446 else 1447 error("Could not request tunnel forwarding."); 1448 } 1449 } 1450 } 1451 1452 static void 1453 check_agent_present(void) 1454 { 1455 if (options.forward_agent) { 1456 /* Clear agent forwarding if we don't have an agent. */ 1457 if (!ssh_agent_present()) 1458 options.forward_agent = 0; 1459 } 1460 } 1461 1462 static int 1463 ssh_session(void) 1464 { 1465 int type; 1466 int interactive = 0; 1467 int have_tty = 0; 1468 struct winsize ws; 1469 char *cp; 1470 const char *display; 1471 1472 /* Enable compression if requested. */ 1473 if (options.compression) { 1474 debug("Requesting compression at level %d.", 1475 options.compression_level); 1476 1477 if (options.compression_level < 1 || 1478 options.compression_level > 9) 1479 fatal("Compression level must be from 1 (fast) to " 1480 "9 (slow, best)."); 1481 1482 /* Send the request. */ 1483 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 1484 packet_put_int(options.compression_level); 1485 packet_send(); 1486 packet_write_wait(); 1487 type = packet_read(); 1488 if (type == SSH_SMSG_SUCCESS) 1489 packet_start_compression(options.compression_level); 1490 else if (type == SSH_SMSG_FAILURE) 1491 logit("Warning: Remote host refused compression."); 1492 else 1493 packet_disconnect("Protocol error waiting for " 1494 "compression response."); 1495 } 1496 /* Allocate a pseudo tty if appropriate. */ 1497 if (tty_flag) { 1498 debug("Requesting pty."); 1499 1500 /* Start the packet. */ 1501 packet_start(SSH_CMSG_REQUEST_PTY); 1502 1503 /* Store TERM in the packet. There is no limit on the 1504 length of the string. */ 1505 cp = getenv("TERM"); 1506 if (!cp) 1507 cp = ""; 1508 packet_put_cstring(cp); 1509 1510 /* Store window size in the packet. */ 1511 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1512 memset(&ws, 0, sizeof(ws)); 1513 packet_put_int((u_int)ws.ws_row); 1514 packet_put_int((u_int)ws.ws_col); 1515 packet_put_int((u_int)ws.ws_xpixel); 1516 packet_put_int((u_int)ws.ws_ypixel); 1517 1518 /* Store tty modes in the packet. */ 1519 tty_make_modes(fileno(stdin), NULL); 1520 1521 /* Send the packet, and wait for it to leave. */ 1522 packet_send(); 1523 packet_write_wait(); 1524 1525 /* Read response from the server. */ 1526 type = packet_read(); 1527 if (type == SSH_SMSG_SUCCESS) { 1528 interactive = 1; 1529 have_tty = 1; 1530 } else if (type == SSH_SMSG_FAILURE) 1531 logit("Warning: Remote host failed or refused to " 1532 "allocate a pseudo tty."); 1533 else 1534 packet_disconnect("Protocol error waiting for pty " 1535 "request response."); 1536 } 1537 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1538 display = getenv("DISPLAY"); 1539 if (options.forward_x11 && display != NULL) { 1540 char *proto, *data; 1541 /* Get reasonable local authentication information. */ 1542 client_x11_get_proto(display, options.xauth_location, 1543 options.forward_x11_trusted, 1544 options.forward_x11_timeout, 1545 &proto, &data); 1546 /* Request forwarding with authentication spoofing. */ 1547 debug("Requesting X11 forwarding with authentication " 1548 "spoofing."); 1549 x11_request_forwarding_with_spoofing(0, display, proto, 1550 data, 0); 1551 /* Read response from the server. */ 1552 type = packet_read(); 1553 if (type == SSH_SMSG_SUCCESS) { 1554 interactive = 1; 1555 } else if (type == SSH_SMSG_FAILURE) { 1556 logit("Warning: Remote host denied X11 forwarding."); 1557 } else { 1558 packet_disconnect("Protocol error waiting for X11 " 1559 "forwarding"); 1560 } 1561 } 1562 /* Tell the packet module whether this is an interactive session. */ 1563 packet_set_interactive(interactive, 1564 options.ip_qos_interactive, options.ip_qos_bulk); 1565 1566 /* Request authentication agent forwarding if appropriate. */ 1567 check_agent_present(); 1568 1569 if (options.forward_agent) { 1570 debug("Requesting authentication agent forwarding."); 1571 auth_request_forwarding(); 1572 1573 /* Read response from the server. */ 1574 type = packet_read(); 1575 packet_check_eom(); 1576 if (type != SSH_SMSG_SUCCESS) 1577 logit("Warning: Remote host denied authentication agent forwarding."); 1578 } 1579 1580 /* Initiate port forwardings. */ 1581 ssh_init_stdio_forwarding(); 1582 ssh_init_forwarding(); 1583 1584 /* Execute a local command */ 1585 if (options.local_command != NULL && 1586 options.permit_local_command) 1587 ssh_local_cmd(options.local_command); 1588 1589 /* 1590 * If requested and we are not interested in replies to remote 1591 * forwarding requests, then let ssh continue in the background. 1592 */ 1593 if (fork_after_authentication_flag) { 1594 if (options.exit_on_forward_failure && 1595 options.num_remote_forwards > 0) { 1596 debug("deferring postauth fork until remote forward " 1597 "confirmation received"); 1598 } else 1599 fork_postauth(); 1600 } 1601 1602 /* 1603 * If a command was specified on the command line, execute the 1604 * command now. Otherwise request the server to start a shell. 1605 */ 1606 if (buffer_len(&command) > 0) { 1607 int len = buffer_len(&command); 1608 if (len > 900) 1609 len = 900; 1610 debug("Sending command: %.*s", len, 1611 (u_char *)buffer_ptr(&command)); 1612 packet_start(SSH_CMSG_EXEC_CMD); 1613 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1614 packet_send(); 1615 packet_write_wait(); 1616 } else { 1617 debug("Requesting shell."); 1618 packet_start(SSH_CMSG_EXEC_SHELL); 1619 packet_send(); 1620 packet_write_wait(); 1621 } 1622 1623 /* Enter the interactive session. */ 1624 return client_loop(have_tty, tty_flag ? 1625 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1626 } 1627 1628 /* request pty/x11/agent/tcpfwd/shell for channel */ 1629 static void 1630 ssh_session2_setup(int id, int success, void *arg) 1631 { 1632 extern char **environ; 1633 const char *display; 1634 int interactive = tty_flag; 1635 1636 if (!success) 1637 return; /* No need for error message, channels code sens one */ 1638 1639 display = getenv("DISPLAY"); 1640 if (options.forward_x11 && display != NULL) { 1641 char *proto, *data; 1642 /* Get reasonable local authentication information. */ 1643 client_x11_get_proto(display, options.xauth_location, 1644 options.forward_x11_trusted, 1645 options.forward_x11_timeout, &proto, &data); 1646 /* Request forwarding with authentication spoofing. */ 1647 debug("Requesting X11 forwarding with authentication " 1648 "spoofing."); 1649 x11_request_forwarding_with_spoofing(id, display, proto, 1650 data, 1); 1651 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); 1652 /* XXX exit_on_forward_failure */ 1653 interactive = 1; 1654 } 1655 1656 check_agent_present(); 1657 if (options.forward_agent) { 1658 debug("Requesting authentication agent forwarding."); 1659 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1660 packet_send(); 1661 } 1662 1663 /* Tell the packet module whether this is an interactive session. */ 1664 packet_set_interactive(interactive, 1665 options.ip_qos_interactive, options.ip_qos_bulk); 1666 1667 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1668 NULL, fileno(stdin), &command, environ); 1669 } 1670 1671 /* open new channel for a session */ 1672 static int 1673 ssh_session2_open(void) 1674 { 1675 Channel *c; 1676 int window, packetmax, in, out, err; 1677 1678 if (stdin_null_flag) { 1679 in = open(_PATH_DEVNULL, O_RDONLY); 1680 } else { 1681 in = dup(STDIN_FILENO); 1682 } 1683 out = dup(STDOUT_FILENO); 1684 err = dup(STDERR_FILENO); 1685 1686 if (in < 0 || out < 0 || err < 0) 1687 fatal("dup() in/out/err failed"); 1688 1689 /* enable nonblocking unless tty */ 1690 if (!isatty(in)) 1691 set_nonblock(in); 1692 if (!isatty(out)) 1693 set_nonblock(out); 1694 if (!isatty(err)) 1695 set_nonblock(err); 1696 1697 window = CHAN_SES_WINDOW_DEFAULT; 1698 packetmax = CHAN_SES_PACKET_DEFAULT; 1699 if (tty_flag) { 1700 window >>= 1; 1701 packetmax >>= 1; 1702 } 1703 c = channel_new( 1704 "session", SSH_CHANNEL_OPENING, in, out, err, 1705 window, packetmax, CHAN_EXTENDED_WRITE, 1706 "client-session", /*nonblock*/0); 1707 1708 debug3("ssh_session2_open: channel_new: %d", c->self); 1709 1710 channel_send_open(c->self); 1711 if (!no_shell_flag) 1712 channel_register_open_confirm(c->self, 1713 ssh_session2_setup, NULL); 1714 1715 return c->self; 1716 } 1717 1718 static int 1719 ssh_session2(void) 1720 { 1721 int id = -1; 1722 1723 /* XXX should be pre-session */ 1724 if (!options.control_persist) 1725 ssh_init_stdio_forwarding(); 1726 ssh_init_forwarding(); 1727 1728 /* Start listening for multiplex clients */ 1729 muxserver_listen(); 1730 1731 /* 1732 * If we are in control persist mode and have a working mux listen 1733 * socket, then prepare to background ourselves and have a foreground 1734 * client attach as a control slave. 1735 * NB. we must save copies of the flags that we override for 1736 * the backgrounding, since we defer attachment of the slave until 1737 * after the connection is fully established (in particular, 1738 * async rfwd replies have been received for ExitOnForwardFailure). 1739 */ 1740 if (options.control_persist && muxserver_sock != -1) { 1741 ostdin_null_flag = stdin_null_flag; 1742 ono_shell_flag = no_shell_flag; 1743 orequest_tty = options.request_tty; 1744 otty_flag = tty_flag; 1745 stdin_null_flag = 1; 1746 no_shell_flag = 1; 1747 tty_flag = 0; 1748 if (!fork_after_authentication_flag) 1749 need_controlpersist_detach = 1; 1750 fork_after_authentication_flag = 1; 1751 } 1752 /* 1753 * ControlPersist mux listen socket setup failed, attempt the 1754 * stdio forward setup that we skipped earlier. 1755 */ 1756 if (options.control_persist && muxserver_sock == -1) 1757 ssh_init_stdio_forwarding(); 1758 1759 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1760 id = ssh_session2_open(); 1761 else { 1762 packet_set_interactive( 1763 options.control_master == SSHCTL_MASTER_NO, 1764 options.ip_qos_interactive, options.ip_qos_bulk); 1765 } 1766 1767 /* If we don't expect to open a new session, then disallow it */ 1768 if (options.control_master == SSHCTL_MASTER_NO && 1769 (datafellows & SSH_NEW_OPENSSH)) { 1770 debug("Requesting no-more-sessions@openssh.com"); 1771 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1772 packet_put_cstring("no-more-sessions@openssh.com"); 1773 packet_put_char(0); 1774 packet_send(); 1775 } 1776 1777 /* Execute a local command */ 1778 if (options.local_command != NULL && 1779 options.permit_local_command) 1780 ssh_local_cmd(options.local_command); 1781 1782 /* 1783 * If requested and we are not interested in replies to remote 1784 * forwarding requests, then let ssh continue in the background. 1785 */ 1786 if (fork_after_authentication_flag) { 1787 if (options.exit_on_forward_failure && 1788 options.num_remote_forwards > 0) { 1789 debug("deferring postauth fork until remote forward " 1790 "confirmation received"); 1791 } else 1792 fork_postauth(); 1793 } 1794 1795 if (options.use_roaming) 1796 request_roaming(); 1797 1798 return client_loop(tty_flag, tty_flag ? 1799 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1800 } 1801 1802 static void 1803 load_public_identity_files(void) 1804 { 1805 char *filename, *cp, thishost[NI_MAXHOST]; 1806 char *pwdir = NULL, *pwname = NULL; 1807 int i = 0; 1808 Key *public; 1809 struct passwd *pw; 1810 u_int n_ids; 1811 char *identity_files[SSH_MAX_IDENTITY_FILES]; 1812 Key *identity_keys[SSH_MAX_IDENTITY_FILES]; 1813 #ifdef ENABLE_PKCS11 1814 Key **keys; 1815 int nkeys; 1816 #endif /* PKCS11 */ 1817 1818 n_ids = 0; 1819 memset(identity_files, 0, sizeof(identity_files)); 1820 memset(identity_keys, 0, sizeof(identity_keys)); 1821 1822 #ifdef ENABLE_PKCS11 1823 if (options.pkcs11_provider != NULL && 1824 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1825 (pkcs11_init(!options.batch_mode) == 0) && 1826 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL, 1827 &keys)) > 0) { 1828 for (i = 0; i < nkeys; i++) { 1829 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1830 key_free(keys[i]); 1831 continue; 1832 } 1833 identity_keys[n_ids] = keys[i]; 1834 identity_files[n_ids] = 1835 xstrdup(options.pkcs11_provider); /* XXX */ 1836 n_ids++; 1837 } 1838 free(keys); 1839 } 1840 #endif /* ENABLE_PKCS11 */ 1841 if ((pw = getpwuid(original_real_uid)) == NULL) 1842 fatal("load_public_identity_files: getpwuid failed"); 1843 pwname = xstrdup(pw->pw_name); 1844 pwdir = xstrdup(pw->pw_dir); 1845 if (gethostname(thishost, sizeof(thishost)) == -1) 1846 fatal("load_public_identity_files: gethostname: %s", 1847 strerror(errno)); 1848 for (i = 0; i < options.num_identity_files; i++) { 1849 if (n_ids >= SSH_MAX_IDENTITY_FILES || 1850 strcasecmp(options.identity_files[i], "none") == 0) { 1851 free(options.identity_files[i]); 1852 continue; 1853 } 1854 cp = tilde_expand_filename(options.identity_files[i], 1855 original_real_uid); 1856 filename = percent_expand(cp, "d", pwdir, 1857 "u", pwname, "l", thishost, "h", host, 1858 "r", options.user, (char *)NULL); 1859 free(cp); 1860 public = key_load_public(filename, NULL); 1861 debug("identity file %s type %d", filename, 1862 public ? public->type : -1); 1863 free(options.identity_files[i]); 1864 identity_files[n_ids] = filename; 1865 identity_keys[n_ids] = public; 1866 1867 if (++n_ids >= SSH_MAX_IDENTITY_FILES) 1868 continue; 1869 1870 /* Try to add the certificate variant too */ 1871 xasprintf(&cp, "%s-cert", filename); 1872 public = key_load_public(cp, NULL); 1873 debug("identity file %s type %d", cp, 1874 public ? public->type : -1); 1875 if (public == NULL) { 1876 free(cp); 1877 continue; 1878 } 1879 if (!key_is_cert(public)) { 1880 debug("%s: key %s type %s is not a certificate", 1881 __func__, cp, key_type(public)); 1882 key_free(public); 1883 free(cp); 1884 continue; 1885 } 1886 identity_keys[n_ids] = public; 1887 /* point to the original path, most likely the private key */ 1888 identity_files[n_ids] = xstrdup(filename); 1889 n_ids++; 1890 } 1891 options.num_identity_files = n_ids; 1892 memcpy(options.identity_files, identity_files, sizeof(identity_files)); 1893 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys)); 1894 1895 explicit_bzero(pwname, strlen(pwname)); 1896 free(pwname); 1897 explicit_bzero(pwdir, strlen(pwdir)); 1898 free(pwdir); 1899 } 1900 1901 static void 1902 main_sigchld_handler(int sig) 1903 { 1904 int save_errno = errno; 1905 pid_t pid; 1906 int status; 1907 1908 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 1909 (pid < 0 && errno == EINTR)) 1910 ; 1911 1912 signal(sig, main_sigchld_handler); 1913 errno = save_errno; 1914 } 1915