1 /* $OpenBSD: ssh.c,v 1.409 2014/10/09 06:21:31 jmc 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/types.h> 51 #include <sys/time.h> 52 #include <sys/wait.h> 53 54 #include <ctype.h> 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <netdb.h> 58 #include <paths.h> 59 #include <pwd.h> 60 #include <signal.h> 61 #include <stddef.h> 62 #include <stdio.h> 63 #include <stdlib.h> 64 #include <string.h> 65 #include <unistd.h> 66 67 #ifdef WITH_OPENSSL 68 #include <openssl/evp.h> 69 #include <openssl/err.h> 70 #endif 71 72 #include "xmalloc.h" 73 #include "ssh.h" 74 #include "ssh1.h" 75 #include "ssh2.h" 76 #include "canohost.h" 77 #include "compat.h" 78 #include "cipher.h" 79 #include "digest.h" 80 #include "packet.h" 81 #include "buffer.h" 82 #include "channels.h" 83 #include "key.h" 84 #include "authfd.h" 85 #include "authfile.h" 86 #include "pathnames.h" 87 #include "dispatch.h" 88 #include "clientloop.h" 89 #include "log.h" 90 #include "misc.h" 91 #include "readconf.h" 92 #include "sshconnect.h" 93 #include "kex.h" 94 #include "mac.h" 95 #include "sshpty.h" 96 #include "match.h" 97 #include "msg.h" 98 #include "uidswap.h" 99 #include "roaming.h" 100 #include "version.h" 101 102 #ifdef ENABLE_PKCS11 103 #include "ssh-pkcs11.h" 104 #endif 105 106 extern char *__progname; 107 108 /* Flag indicating whether debug mode is on. May be set on the command line. */ 109 int debug_flag = 0; 110 111 /* Flag indicating whether a tty should be requested */ 112 int tty_flag = 0; 113 114 /* don't exec a shell */ 115 int no_shell_flag = 0; 116 117 /* 118 * Flag indicating that nothing should be read from stdin. This can be set 119 * on the command line. 120 */ 121 int stdin_null_flag = 0; 122 123 /* 124 * Flag indicating that the current process should be backgrounded and 125 * a new slave launched in the foreground for ControlPersist. 126 */ 127 int need_controlpersist_detach = 0; 128 129 /* Copies of flags for ControlPersist foreground slave */ 130 int ostdin_null_flag, ono_shell_flag, otty_flag, orequest_tty; 131 132 /* 133 * Flag indicating that ssh should fork after authentication. This is useful 134 * so that the passphrase can be entered manually, and then ssh goes to the 135 * background. 136 */ 137 int fork_after_authentication_flag = 0; 138 139 /* forward stdio to remote host and port */ 140 char *stdio_forward_host = NULL; 141 int stdio_forward_port = 0; 142 143 /* 144 * General data structure for command line options and options configurable 145 * in configuration files. See readconf.h. 146 */ 147 Options options; 148 149 /* optional user configfile */ 150 char *config = NULL; 151 152 /* 153 * Name of the host we are connecting to. This is the name given on the 154 * command line, or the HostName specified for the user-supplied name in a 155 * configuration file. 156 */ 157 char *host; 158 159 /* socket address the host resolves to */ 160 struct sockaddr_storage hostaddr; 161 162 /* Private host keys. */ 163 Sensitive sensitive_data; 164 165 /* Original real UID. */ 166 uid_t original_real_uid; 167 uid_t original_effective_uid; 168 169 /* command to be executed */ 170 Buffer command; 171 172 /* Should we execute a command or invoke a subsystem? */ 173 int subsystem_flag = 0; 174 175 /* # of replies received for global requests */ 176 static int remote_forward_confirms_received = 0; 177 178 /* mux.c */ 179 extern int muxserver_sock; 180 extern u_int muxclient_command; 181 182 /* Prints a help message to the user. This function never returns. */ 183 184 static void 185 usage(void) 186 { 187 fprintf(stderr, 188 "usage: ssh [-1246AaCfGgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec]\n" 189 " [-D [bind_address:]port] [-E log_file] [-e escape_char]\n" 190 " [-F configfile] [-I pkcs11] [-i identity_file]\n" 191 " [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec]\n" 192 " [-O ctl_cmd] [-o option] [-p port]\n" 193 " [-Q cipher | cipher-auth | mac | kex | key]\n" 194 " [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port]\n" 195 " [-w local_tun[:remote_tun]] [user@]hostname [command]\n" 196 ); 197 exit(255); 198 } 199 200 static int ssh_session(void); 201 static int ssh_session2(void); 202 static void load_public_identity_files(void); 203 static void main_sigchld_handler(int); 204 205 /* from muxclient.c */ 206 void muxclient(const char *); 207 void muxserver_listen(void); 208 209 /* ~/ expand a list of paths. NB. assumes path[n] is heap-allocated. */ 210 static void 211 tilde_expand_paths(char **paths, u_int num_paths) 212 { 213 u_int i; 214 char *cp; 215 216 for (i = 0; i < num_paths; i++) { 217 cp = tilde_expand_filename(paths[i], original_real_uid); 218 free(paths[i]); 219 paths[i] = cp; 220 } 221 } 222 223 /* 224 * Attempt to resolve a host name / port to a set of addresses and 225 * optionally return any CNAMEs encountered along the way. 226 * Returns NULL on failure. 227 * NB. this function must operate with a options having undefined members. 228 */ 229 static struct addrinfo * 230 resolve_host(const char *name, int port, int logerr, char *cname, size_t clen) 231 { 232 char strport[NI_MAXSERV]; 233 struct addrinfo hints, *res; 234 int gaierr, loglevel = SYSLOG_LEVEL_DEBUG1; 235 236 if (port <= 0) 237 port = default_ssh_port(); 238 239 snprintf(strport, sizeof strport, "%u", port); 240 memset(&hints, 0, sizeof(hints)); 241 hints.ai_family = options.address_family == -1 ? 242 AF_UNSPEC : options.address_family; 243 hints.ai_socktype = SOCK_STREAM; 244 if (cname != NULL) 245 hints.ai_flags = AI_CANONNAME; 246 if ((gaierr = getaddrinfo(name, strport, &hints, &res)) != 0) { 247 if (logerr || (gaierr != EAI_NONAME && gaierr != EAI_NODATA)) 248 loglevel = SYSLOG_LEVEL_ERROR; 249 do_log2(loglevel, "%s: Could not resolve hostname %.100s: %s", 250 __progname, name, ssh_gai_strerror(gaierr)); 251 return NULL; 252 } 253 if (cname != NULL && res->ai_canonname != NULL) { 254 if (strlcpy(cname, res->ai_canonname, clen) >= clen) { 255 error("%s: host \"%s\" cname \"%s\" too long (max %lu)", 256 __func__, name, res->ai_canonname, (u_long)clen); 257 if (clen > 0) 258 *cname = '\0'; 259 } 260 } 261 return res; 262 } 263 264 /* 265 * Check whether the cname is a permitted replacement for the hostname 266 * and perform the replacement if it is. 267 * NB. this function must operate with a options having undefined members. 268 */ 269 static int 270 check_follow_cname(char **namep, const char *cname) 271 { 272 int i; 273 struct allowed_cname *rule; 274 275 if (*cname == '\0' || options.num_permitted_cnames == 0 || 276 strcmp(*namep, cname) == 0) 277 return 0; 278 if (options.canonicalize_hostname == SSH_CANONICALISE_NO) 279 return 0; 280 /* 281 * Don't attempt to canonicalize names that will be interpreted by 282 * a proxy unless the user specifically requests so. 283 */ 284 if (!option_clear_or_none(options.proxy_command) && 285 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS) 286 return 0; 287 debug3("%s: check \"%s\" CNAME \"%s\"", __func__, *namep, cname); 288 for (i = 0; i < options.num_permitted_cnames; i++) { 289 rule = options.permitted_cnames + i; 290 if (match_pattern_list(*namep, rule->source_list, 291 strlen(rule->source_list), 1) != 1 || 292 match_pattern_list(cname, rule->target_list, 293 strlen(rule->target_list), 1) != 1) 294 continue; 295 verbose("Canonicalized DNS aliased hostname " 296 "\"%s\" => \"%s\"", *namep, cname); 297 free(*namep); 298 *namep = xstrdup(cname); 299 return 1; 300 } 301 return 0; 302 } 303 304 /* 305 * Attempt to resolve the supplied hostname after applying the user's 306 * canonicalization rules. Returns the address list for the host or NULL 307 * if no name was found after canonicalization. 308 * NB. this function must operate with a options having undefined members. 309 */ 310 static struct addrinfo * 311 resolve_canonicalize(char **hostp, int port) 312 { 313 int i, ndots; 314 char *cp, *fullhost, cname_target[NI_MAXHOST]; 315 struct addrinfo *addrs; 316 317 if (options.canonicalize_hostname == SSH_CANONICALISE_NO) 318 return NULL; 319 320 /* 321 * Don't attempt to canonicalize names that will be interpreted by 322 * a proxy unless the user specifically requests so. 323 */ 324 if (!option_clear_or_none(options.proxy_command) && 325 options.canonicalize_hostname != SSH_CANONICALISE_ALWAYS) 326 return NULL; 327 328 /* Don't apply canonicalization to sufficiently-qualified hostnames */ 329 ndots = 0; 330 for (cp = *hostp; *cp != '\0'; cp++) { 331 if (*cp == '.') 332 ndots++; 333 } 334 if (ndots > options.canonicalize_max_dots) { 335 debug3("%s: not canonicalizing hostname \"%s\" (max dots %d)", 336 __func__, *hostp, options.canonicalize_max_dots); 337 return NULL; 338 } 339 /* Attempt each supplied suffix */ 340 for (i = 0; i < options.num_canonical_domains; i++) { 341 *cname_target = '\0'; 342 xasprintf(&fullhost, "%s.%s.", *hostp, 343 options.canonical_domains[i]); 344 debug3("%s: attempting \"%s\" => \"%s\"", __func__, 345 *hostp, fullhost); 346 if ((addrs = resolve_host(fullhost, port, 0, 347 cname_target, sizeof(cname_target))) == NULL) { 348 free(fullhost); 349 continue; 350 } 351 /* Remove trailing '.' */ 352 fullhost[strlen(fullhost) - 1] = '\0'; 353 /* Follow CNAME if requested */ 354 if (!check_follow_cname(&fullhost, cname_target)) { 355 debug("Canonicalized hostname \"%s\" => \"%s\"", 356 *hostp, fullhost); 357 } 358 free(*hostp); 359 *hostp = fullhost; 360 return addrs; 361 } 362 if (!options.canonicalize_fallback_local) 363 fatal("%s: Could not resolve host \"%s\"", __progname, *hostp); 364 debug2("%s: host %s not found in any suffix", __func__, *hostp); 365 return NULL; 366 } 367 368 /* 369 * Read per-user configuration file. Ignore the system wide config 370 * file if the user specifies a config file on the command line. 371 */ 372 static void 373 process_config_files(const char *host_arg, struct passwd *pw, int post_canon) 374 { 375 char buf[MAXPATHLEN]; 376 int r; 377 378 if (config != NULL) { 379 if (strcasecmp(config, "none") != 0 && 380 !read_config_file(config, pw, host, host_arg, &options, 381 SSHCONF_USERCONF | (post_canon ? SSHCONF_POSTCANON : 0))) 382 fatal("Can't open user config file %.100s: " 383 "%.100s", config, strerror(errno)); 384 } else { 385 r = snprintf(buf, sizeof buf, "%s/%s", pw->pw_dir, 386 _PATH_SSH_USER_CONFFILE); 387 if (r > 0 && (size_t)r < sizeof(buf)) 388 (void)read_config_file(buf, pw, host, host_arg, 389 &options, SSHCONF_CHECKPERM | SSHCONF_USERCONF | 390 (post_canon ? SSHCONF_POSTCANON : 0)); 391 392 /* Read systemwide configuration file after user config. */ 393 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, 394 host, host_arg, &options, 395 post_canon ? SSHCONF_POSTCANON : 0); 396 } 397 } 398 399 /* Rewrite the port number in an addrinfo list of addresses */ 400 static void 401 set_addrinfo_port(struct addrinfo *addrs, int port) 402 { 403 struct addrinfo *addr; 404 405 for (addr = addrs; addr != NULL; addr = addr->ai_next) { 406 switch (addr->ai_family) { 407 case AF_INET: 408 ((struct sockaddr_in *)addr->ai_addr)-> 409 sin_port = htons(port); 410 break; 411 case AF_INET6: 412 ((struct sockaddr_in6 *)addr->ai_addr)-> 413 sin6_port = htons(port); 414 break; 415 } 416 } 417 } 418 419 /* 420 * Main program for the ssh client. 421 */ 422 int 423 main(int ac, char **av) 424 { 425 int i, r, opt, exit_status, use_syslog, config_test = 0; 426 char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg, *logfile; 427 char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV]; 428 char cname[NI_MAXHOST]; 429 struct stat st; 430 struct passwd *pw; 431 int timeout_ms; 432 extern int optind, optreset; 433 extern char *optarg; 434 struct Forward fwd; 435 struct addrinfo *addrs = NULL; 436 struct ssh_digest_ctx *md; 437 u_char conn_hash[SSH_DIGEST_MAX_LENGTH]; 438 char *conn_hash_hex; 439 440 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 441 sanitise_stdfd(); 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 /* If we are installed setuid root be careful to not drop core. */ 466 if (original_real_uid != original_effective_uid) { 467 struct rlimit rlim; 468 rlim.rlim_cur = rlim.rlim_max = 0; 469 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 470 fatal("setrlimit failed: %.100s", strerror(errno)); 471 } 472 /* Get user data. */ 473 pw = getpwuid(original_real_uid); 474 if (!pw) { 475 logit("No user exists for uid %lu", (u_long)original_real_uid); 476 exit(255); 477 } 478 /* Take a copy of the returned structure. */ 479 pw = pwcopy(pw); 480 481 /* 482 * Set our umask to something reasonable, as some files are created 483 * with the default umask. This will make them world-readable but 484 * writable only by the owner, which is ok for all files for which we 485 * don't set the modes explicitly. 486 */ 487 umask(022); 488 489 /* 490 * Initialize option structure to indicate that no values have been 491 * set. 492 */ 493 initialize_options(&options); 494 495 /* Parse command-line arguments. */ 496 host = NULL; 497 use_syslog = 0; 498 logfile = NULL; 499 argv0 = av[0]; 500 501 again: 502 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 503 "ACD:E:F:GI:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) { 504 switch (opt) { 505 case '1': 506 options.protocol = SSH_PROTO_1; 507 break; 508 case '2': 509 options.protocol = SSH_PROTO_2; 510 break; 511 case '4': 512 options.address_family = AF_INET; 513 break; 514 case '6': 515 options.address_family = AF_INET6; 516 break; 517 case 'n': 518 stdin_null_flag = 1; 519 break; 520 case 'f': 521 fork_after_authentication_flag = 1; 522 stdin_null_flag = 1; 523 break; 524 case 'x': 525 options.forward_x11 = 0; 526 break; 527 case 'X': 528 options.forward_x11 = 1; 529 break; 530 case 'y': 531 use_syslog = 1; 532 break; 533 case 'E': 534 logfile = xstrdup(optarg); 535 break; 536 case 'G': 537 config_test = 1; 538 break; 539 case 'Y': 540 options.forward_x11 = 1; 541 options.forward_x11_trusted = 1; 542 break; 543 case 'g': 544 options.fwd_opts.gateway_ports = 1; 545 break; 546 case 'O': 547 if (stdio_forward_host != NULL) 548 fatal("Cannot specify multiplexing " 549 "command with -W"); 550 else if (muxclient_command != 0) 551 fatal("Multiplexing command already specified"); 552 if (strcmp(optarg, "check") == 0) 553 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; 554 else if (strcmp(optarg, "forward") == 0) 555 muxclient_command = SSHMUX_COMMAND_FORWARD; 556 else if (strcmp(optarg, "exit") == 0) 557 muxclient_command = SSHMUX_COMMAND_TERMINATE; 558 else if (strcmp(optarg, "stop") == 0) 559 muxclient_command = SSHMUX_COMMAND_STOP; 560 else if (strcmp(optarg, "cancel") == 0) 561 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD; 562 else 563 fatal("Invalid multiplex command."); 564 break; 565 case 'P': /* deprecated */ 566 options.use_privileged_port = 0; 567 break; 568 case 'Q': 569 cp = NULL; 570 if (strcmp(optarg, "cipher") == 0) 571 cp = cipher_alg_list('\n', 0); 572 else if (strcmp(optarg, "cipher-auth") == 0) 573 cp = cipher_alg_list('\n', 1); 574 else if (strcmp(optarg, "mac") == 0) 575 cp = mac_alg_list('\n'); 576 else if (strcmp(optarg, "kex") == 0) 577 cp = kex_alg_list('\n'); 578 else if (strcmp(optarg, "key") == 0) 579 cp = key_alg_list(0, 0); 580 else if (strcmp(optarg, "key-cert") == 0) 581 cp = key_alg_list(1, 0); 582 else if (strcmp(optarg, "key-plain") == 0) 583 cp = key_alg_list(0, 1); 584 if (cp == NULL) 585 fatal("Unsupported query \"%s\"", optarg); 586 printf("%s\n", cp); 587 free(cp); 588 exit(0); 589 break; 590 case 'a': 591 options.forward_agent = 0; 592 break; 593 case 'A': 594 options.forward_agent = 1; 595 break; 596 case 'k': 597 options.gss_deleg_creds = 0; 598 break; 599 case 'K': 600 options.gss_authentication = 1; 601 options.gss_deleg_creds = 1; 602 break; 603 case 'i': 604 if (stat(optarg, &st) < 0) { 605 fprintf(stderr, "Warning: Identity file %s " 606 "not accessible: %s.\n", optarg, 607 strerror(errno)); 608 break; 609 } 610 add_identity_file(&options, NULL, optarg, 1); 611 break; 612 case 'I': 613 #ifdef ENABLE_PKCS11 614 options.pkcs11_provider = xstrdup(optarg); 615 #else 616 fprintf(stderr, "no support for PKCS#11.\n"); 617 #endif 618 break; 619 case 't': 620 if (options.request_tty == REQUEST_TTY_YES) 621 options.request_tty = REQUEST_TTY_FORCE; 622 else 623 options.request_tty = REQUEST_TTY_YES; 624 break; 625 case 'v': 626 if (debug_flag == 0) { 627 debug_flag = 1; 628 options.log_level = SYSLOG_LEVEL_DEBUG1; 629 } else { 630 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 631 options.log_level++; 632 } 633 break; 634 case 'V': 635 fprintf(stderr, "%s, %s\n", 636 SSH_VERSION, 637 #ifdef WITH_OPENSSL 638 SSLeay_version(SSLEAY_VERSION) 639 #else 640 "without OpenSSL" 641 #endif 642 ); 643 if (opt == 'V') 644 exit(0); 645 break; 646 case 'w': 647 if (options.tun_open == -1) 648 options.tun_open = SSH_TUNMODE_DEFAULT; 649 options.tun_local = a2tun(optarg, &options.tun_remote); 650 if (options.tun_local == SSH_TUNID_ERR) { 651 fprintf(stderr, 652 "Bad tun device '%s'\n", optarg); 653 exit(255); 654 } 655 break; 656 case 'W': 657 if (stdio_forward_host != NULL) 658 fatal("stdio forward already specified"); 659 if (muxclient_command != 0) 660 fatal("Cannot specify stdio forward with -O"); 661 if (parse_forward(&fwd, optarg, 1, 0)) { 662 stdio_forward_host = fwd.listen_host; 663 stdio_forward_port = fwd.listen_port; 664 free(fwd.connect_host); 665 } else { 666 fprintf(stderr, 667 "Bad stdio forwarding specification '%s'\n", 668 optarg); 669 exit(255); 670 } 671 options.request_tty = REQUEST_TTY_NO; 672 no_shell_flag = 1; 673 options.clear_forwardings = 1; 674 options.exit_on_forward_failure = 1; 675 break; 676 case 'q': 677 options.log_level = SYSLOG_LEVEL_QUIET; 678 break; 679 case 'e': 680 if (optarg[0] == '^' && optarg[2] == 0 && 681 (u_char) optarg[1] >= 64 && 682 (u_char) optarg[1] < 128) 683 options.escape_char = (u_char) optarg[1] & 31; 684 else if (strlen(optarg) == 1) 685 options.escape_char = (u_char) optarg[0]; 686 else if (strcmp(optarg, "none") == 0) 687 options.escape_char = SSH_ESCAPECHAR_NONE; 688 else { 689 fprintf(stderr, "Bad escape character '%s'.\n", 690 optarg); 691 exit(255); 692 } 693 break; 694 case 'c': 695 if (ciphers_valid(optarg)) { 696 /* SSH2 only */ 697 options.ciphers = xstrdup(optarg); 698 options.cipher = SSH_CIPHER_INVALID; 699 } else { 700 /* SSH1 only */ 701 options.cipher = cipher_number(optarg); 702 if (options.cipher == -1) { 703 fprintf(stderr, 704 "Unknown cipher type '%s'\n", 705 optarg); 706 exit(255); 707 } 708 if (options.cipher == SSH_CIPHER_3DES) 709 options.ciphers = "3des-cbc"; 710 else if (options.cipher == SSH_CIPHER_BLOWFISH) 711 options.ciphers = "blowfish-cbc"; 712 else 713 options.ciphers = (char *)-1; 714 } 715 break; 716 case 'm': 717 if (mac_valid(optarg)) 718 options.macs = xstrdup(optarg); 719 else { 720 fprintf(stderr, "Unknown mac type '%s'\n", 721 optarg); 722 exit(255); 723 } 724 break; 725 case 'M': 726 if (options.control_master == SSHCTL_MASTER_YES) 727 options.control_master = SSHCTL_MASTER_ASK; 728 else 729 options.control_master = SSHCTL_MASTER_YES; 730 break; 731 case 'p': 732 options.port = a2port(optarg); 733 if (options.port <= 0) { 734 fprintf(stderr, "Bad port '%s'\n", optarg); 735 exit(255); 736 } 737 break; 738 case 'l': 739 options.user = optarg; 740 break; 741 742 case 'L': 743 if (parse_forward(&fwd, optarg, 0, 0)) 744 add_local_forward(&options, &fwd); 745 else { 746 fprintf(stderr, 747 "Bad local forwarding specification '%s'\n", 748 optarg); 749 exit(255); 750 } 751 break; 752 753 case 'R': 754 if (parse_forward(&fwd, optarg, 0, 1)) { 755 add_remote_forward(&options, &fwd); 756 } else { 757 fprintf(stderr, 758 "Bad remote forwarding specification " 759 "'%s'\n", optarg); 760 exit(255); 761 } 762 break; 763 764 case 'D': 765 if (parse_forward(&fwd, optarg, 1, 0)) { 766 add_local_forward(&options, &fwd); 767 } else { 768 fprintf(stderr, 769 "Bad dynamic forwarding specification " 770 "'%s'\n", optarg); 771 exit(255); 772 } 773 break; 774 775 case 'C': 776 options.compression = 1; 777 break; 778 case 'N': 779 no_shell_flag = 1; 780 options.request_tty = REQUEST_TTY_NO; 781 break; 782 case 'T': 783 options.request_tty = REQUEST_TTY_NO; 784 break; 785 case 'o': 786 line = xstrdup(optarg); 787 if (process_config_line(&options, pw, 788 host ? host : "", host ? host : "", line, 789 "command-line", 0, NULL, SSHCONF_USERCONF) != 0) 790 exit(255); 791 free(line); 792 break; 793 case 's': 794 subsystem_flag = 1; 795 break; 796 case 'S': 797 if (options.control_path != NULL) 798 free(options.control_path); 799 options.control_path = xstrdup(optarg); 800 break; 801 case 'b': 802 options.bind_address = optarg; 803 break; 804 case 'F': 805 config = optarg; 806 break; 807 default: 808 usage(); 809 } 810 } 811 812 ac -= optind; 813 av += optind; 814 815 if (ac > 0 && !host) { 816 if (strrchr(*av, '@')) { 817 p = xstrdup(*av); 818 cp = strrchr(p, '@'); 819 if (cp == NULL || cp == p) 820 usage(); 821 options.user = p; 822 *cp = '\0'; 823 host = xstrdup(++cp); 824 } else 825 host = xstrdup(*av); 826 if (ac > 1) { 827 optind = optreset = 1; 828 goto again; 829 } 830 ac--, av++; 831 } 832 833 /* Check that we got a host name. */ 834 if (!host) 835 usage(); 836 837 host_arg = xstrdup(host); 838 839 #ifdef WITH_OPENSSL 840 OpenSSL_add_all_algorithms(); 841 ERR_load_crypto_strings(); 842 #endif 843 844 /* Initialize the command to execute on remote host. */ 845 buffer_init(&command); 846 847 /* 848 * Save the command to execute on the remote host in a buffer. There 849 * is no limit on the length of the command, except by the maximum 850 * packet size. Also sets the tty flag if there is no command. 851 */ 852 if (!ac) { 853 /* No command specified - execute shell on a tty. */ 854 if (subsystem_flag) { 855 fprintf(stderr, 856 "You must specify a subsystem to invoke.\n"); 857 usage(); 858 } 859 } else { 860 /* A command has been specified. Store it into the buffer. */ 861 for (i = 0; i < ac; i++) { 862 if (i) 863 buffer_append(&command, " ", 1); 864 buffer_append(&command, av[i], strlen(av[i])); 865 } 866 } 867 868 /* Cannot fork to background if no command. */ 869 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 870 !no_shell_flag) 871 fatal("Cannot fork into background without a command " 872 "to execute."); 873 874 /* 875 * Initialize "log" output. Since we are the client all output 876 * goes to stderr unless otherwise specified by -y or -E. 877 */ 878 if (use_syslog && logfile != NULL) 879 fatal("Can't specify both -y and -E"); 880 if (logfile != NULL) { 881 log_redirect_stderr_to(logfile); 882 free(logfile); 883 } 884 log_init(argv0, 885 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 886 SYSLOG_FACILITY_USER, !use_syslog); 887 888 if (debug_flag) 889 logit("%s, %s", SSH_VERSION, 890 #ifdef WITH_OPENSSL 891 SSLeay_version(SSLEAY_VERSION) 892 #else 893 "without OpenSSL" 894 #endif 895 ); 896 897 /* Parse the configuration files */ 898 process_config_files(host_arg, pw, 0); 899 900 /* Hostname canonicalisation needs a few options filled. */ 901 fill_default_options_for_canonicalization(&options); 902 903 /* If the user has replaced the hostname then take it into use now */ 904 if (options.hostname != NULL) { 905 /* NB. Please keep in sync with readconf.c:match_cfg_line() */ 906 cp = percent_expand(options.hostname, 907 "h", host, (char *)NULL); 908 free(host); 909 host = cp; 910 free(options.hostname); 911 options.hostname = xstrdup(host); 912 } 913 914 /* If canonicalization requested then try to apply it */ 915 lowercase(host); 916 if (options.canonicalize_hostname != SSH_CANONICALISE_NO) 917 addrs = resolve_canonicalize(&host, options.port); 918 919 /* 920 * If CanonicalizePermittedCNAMEs have been specified but 921 * other canonicalization did not happen (by not being requested 922 * or by failing with fallback) then the hostname may still be changed 923 * as a result of CNAME following. 924 * 925 * Try to resolve the bare hostname name using the system resolver's 926 * usual search rules and then apply the CNAME follow rules. 927 * 928 * Skip the lookup if a ProxyCommand is being used unless the user 929 * has specifically requested canonicalisation for this case via 930 * CanonicalizeHostname=always 931 */ 932 if (addrs == NULL && options.num_permitted_cnames != 0 && 933 (option_clear_or_none(options.proxy_command) || 934 options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) { 935 if ((addrs = resolve_host(host, options.port, 936 option_clear_or_none(options.proxy_command), 937 cname, sizeof(cname))) == NULL) { 938 /* Don't fatal proxied host names not in the DNS */ 939 if (option_clear_or_none(options.proxy_command)) 940 cleanup_exit(255); /* logged in resolve_host */ 941 } else 942 check_follow_cname(&host, cname); 943 } 944 945 /* 946 * If canonicalisation is enabled then re-parse the configuration 947 * files as new stanzas may match. 948 */ 949 if (options.canonicalize_hostname != 0) { 950 debug("Re-reading configuration after hostname " 951 "canonicalisation"); 952 free(options.hostname); 953 options.hostname = xstrdup(host); 954 process_config_files(host_arg, pw, 1); 955 /* 956 * Address resolution happens early with canonicalisation 957 * enabled and the port number may have changed since, so 958 * reset it in address list 959 */ 960 if (addrs != NULL && options.port > 0) 961 set_addrinfo_port(addrs, options.port); 962 } 963 964 /* Fill configuration defaults. */ 965 fill_default_options(&options); 966 967 if (options.port == 0) 968 options.port = default_ssh_port(); 969 channel_set_af(options.address_family); 970 971 /* Tidy and check options */ 972 if (options.host_key_alias != NULL) 973 lowercase(options.host_key_alias); 974 if (options.proxy_command != NULL && 975 strcmp(options.proxy_command, "-") == 0 && 976 options.proxy_use_fdpass) 977 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible"); 978 if (original_effective_uid != 0) 979 options.use_privileged_port = 0; 980 981 /* reinit */ 982 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 983 984 if (options.request_tty == REQUEST_TTY_YES || 985 options.request_tty == REQUEST_TTY_FORCE) 986 tty_flag = 1; 987 988 /* Allocate a tty by default if no command specified. */ 989 if (buffer_len(&command) == 0) 990 tty_flag = options.request_tty != REQUEST_TTY_NO; 991 992 /* Force no tty */ 993 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0) 994 tty_flag = 0; 995 /* Do not allocate a tty if stdin is not a tty. */ 996 if ((!isatty(fileno(stdin)) || stdin_null_flag) && 997 options.request_tty != REQUEST_TTY_FORCE) { 998 if (tty_flag) 999 logit("Pseudo-terminal will not be allocated because " 1000 "stdin is not a terminal."); 1001 tty_flag = 0; 1002 } 1003 1004 if (options.user == NULL) 1005 options.user = xstrdup(pw->pw_name); 1006 1007 if (gethostname(thishost, sizeof(thishost)) == -1) 1008 fatal("gethostname: %s", strerror(errno)); 1009 strlcpy(shorthost, thishost, sizeof(shorthost)); 1010 shorthost[strcspn(thishost, ".")] = '\0'; 1011 snprintf(portstr, sizeof(portstr), "%d", options.port); 1012 1013 if ((md = ssh_digest_start(SSH_DIGEST_SHA1)) == NULL || 1014 ssh_digest_update(md, thishost, strlen(thishost)) < 0 || 1015 ssh_digest_update(md, host, strlen(host)) < 0 || 1016 ssh_digest_update(md, portstr, strlen(portstr)) < 0 || 1017 ssh_digest_update(md, options.user, strlen(options.user)) < 0 || 1018 ssh_digest_final(md, conn_hash, sizeof(conn_hash)) < 0) 1019 fatal("%s: mux digest failed", __func__); 1020 ssh_digest_free(md); 1021 conn_hash_hex = tohex(conn_hash, ssh_digest_bytes(SSH_DIGEST_SHA1)); 1022 1023 if (options.local_command != NULL) { 1024 debug3("expanding LocalCommand: %s", options.local_command); 1025 cp = options.local_command; 1026 options.local_command = percent_expand(cp, 1027 "C", conn_hash_hex, 1028 "L", shorthost, 1029 "d", pw->pw_dir, 1030 "h", host, 1031 "l", thishost, 1032 "n", host_arg, 1033 "p", portstr, 1034 "r", options.user, 1035 "u", pw->pw_name, 1036 (char *)NULL); 1037 debug3("expanded LocalCommand: %s", options.local_command); 1038 free(cp); 1039 } 1040 1041 if (options.control_path != NULL) { 1042 cp = tilde_expand_filename(options.control_path, 1043 original_real_uid); 1044 free(options.control_path); 1045 options.control_path = percent_expand(cp, 1046 "C", conn_hash_hex, 1047 "L", shorthost, 1048 "h", host, 1049 "l", thishost, 1050 "n", host_arg, 1051 "p", portstr, 1052 "r", options.user, 1053 "u", pw->pw_name, 1054 (char *)NULL); 1055 free(cp); 1056 } 1057 free(conn_hash_hex); 1058 1059 if (config_test) { 1060 dump_client_config(&options, host); 1061 exit(0); 1062 } 1063 1064 if (muxclient_command != 0 && options.control_path == NULL) 1065 fatal("No ControlPath specified for \"-O\" command"); 1066 if (options.control_path != NULL) 1067 muxclient(options.control_path); 1068 1069 /* 1070 * If hostname canonicalisation was not enabled, then we may not 1071 * have yet resolved the hostname. Do so now. 1072 */ 1073 if (addrs == NULL && options.proxy_command == NULL) { 1074 if ((addrs = resolve_host(host, options.port, 1, 1075 cname, sizeof(cname))) == NULL) 1076 cleanup_exit(255); /* resolve_host logs the error */ 1077 } 1078 1079 timeout_ms = options.connection_timeout * 1000; 1080 1081 /* Open a connection to the remote host. */ 1082 if (ssh_connect(host, addrs, &hostaddr, options.port, 1083 options.address_family, options.connection_attempts, 1084 &timeout_ms, options.tcp_keep_alive, 1085 options.use_privileged_port) != 0) 1086 exit(255); 1087 1088 if (addrs != NULL) 1089 freeaddrinfo(addrs); 1090 1091 packet_set_timeout(options.server_alive_interval, 1092 options.server_alive_count_max); 1093 1094 if (timeout_ms > 0) 1095 debug3("timeout: %d ms remain after connect", timeout_ms); 1096 1097 /* 1098 * If we successfully made the connection, load the host private key 1099 * in case we will need it later for combined rsa-rhosts 1100 * authentication. This must be done before releasing extra 1101 * privileges, because the file is only readable by root. 1102 * If we cannot access the private keys, load the public keys 1103 * instead and try to execute the ssh-keysign helper instead. 1104 */ 1105 sensitive_data.nkeys = 0; 1106 sensitive_data.keys = NULL; 1107 sensitive_data.external_keysign = 0; 1108 if (options.rhosts_rsa_authentication || 1109 options.hostbased_authentication) { 1110 sensitive_data.nkeys = 9; 1111 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 1112 sizeof(Key)); 1113 1114 PRIV_START; 1115 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 1116 _PATH_HOST_KEY_FILE, "", NULL, NULL); 1117 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA, 1118 _PATH_HOST_DSA_KEY_FILE, "", NULL); 1119 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA, 1120 _PATH_HOST_ECDSA_KEY_FILE, "", NULL); 1121 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA, 1122 _PATH_HOST_RSA_KEY_FILE, "", NULL); 1123 sensitive_data.keys[4] = key_load_private_cert(KEY_ED25519, 1124 _PATH_HOST_ED25519_KEY_FILE, "", NULL); 1125 sensitive_data.keys[5] = key_load_private_type(KEY_DSA, 1126 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 1127 sensitive_data.keys[6] = key_load_private_type(KEY_ECDSA, 1128 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL); 1129 sensitive_data.keys[7] = key_load_private_type(KEY_RSA, 1130 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 1131 sensitive_data.keys[8] = key_load_private_type(KEY_ED25519, 1132 _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL); 1133 PRIV_END; 1134 1135 if (options.hostbased_authentication == 1 && 1136 sensitive_data.keys[0] == NULL && 1137 sensitive_data.keys[5] == NULL && 1138 sensitive_data.keys[6] == NULL && 1139 sensitive_data.keys[7] == NULL && 1140 sensitive_data.keys[8] == NULL) { 1141 sensitive_data.keys[1] = key_load_cert( 1142 _PATH_HOST_DSA_KEY_FILE); 1143 sensitive_data.keys[2] = key_load_cert( 1144 _PATH_HOST_ECDSA_KEY_FILE); 1145 sensitive_data.keys[3] = key_load_cert( 1146 _PATH_HOST_RSA_KEY_FILE); 1147 sensitive_data.keys[4] = key_load_cert( 1148 _PATH_HOST_ED25519_KEY_FILE); 1149 sensitive_data.keys[5] = key_load_public( 1150 _PATH_HOST_DSA_KEY_FILE, NULL); 1151 sensitive_data.keys[6] = key_load_public( 1152 _PATH_HOST_ECDSA_KEY_FILE, NULL); 1153 sensitive_data.keys[7] = key_load_public( 1154 _PATH_HOST_RSA_KEY_FILE, NULL); 1155 sensitive_data.keys[8] = key_load_public( 1156 _PATH_HOST_ED25519_KEY_FILE, NULL); 1157 sensitive_data.external_keysign = 1; 1158 } 1159 } 1160 /* 1161 * Get rid of any extra privileges that we may have. We will no 1162 * longer need them. Also, extra privileges could make it very hard 1163 * to read identity files and other non-world-readable files from the 1164 * user's home directory if it happens to be on a NFS volume where 1165 * root is mapped to nobody. 1166 */ 1167 if (original_effective_uid == 0) { 1168 PRIV_START; 1169 permanently_set_uid(pw); 1170 } 1171 1172 /* 1173 * Now that we are back to our own permissions, create ~/.ssh 1174 * directory if it doesn't already exist. 1175 */ 1176 if (config == NULL) { 1177 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 1178 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 1179 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) 1180 if (mkdir(buf, 0700) < 0) 1181 error("Could not create directory '%.200s'.", 1182 buf); 1183 } 1184 1185 /* load options.identity_files */ 1186 load_public_identity_files(); 1187 1188 /* Expand ~ in known host file names. */ 1189 tilde_expand_paths(options.system_hostfiles, 1190 options.num_system_hostfiles); 1191 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles); 1192 1193 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 1194 signal(SIGCHLD, main_sigchld_handler); 1195 1196 /* Log into the remote system. Never returns if the login fails. */ 1197 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 1198 options.port, pw, timeout_ms); 1199 1200 if (packet_connection_is_on_socket()) { 1201 verbose("Authenticated to %s ([%s]:%d).", host, 1202 get_remote_ipaddr(), get_remote_port()); 1203 } else { 1204 verbose("Authenticated to %s (via proxy).", host); 1205 } 1206 1207 /* We no longer need the private host keys. Clear them now. */ 1208 if (sensitive_data.nkeys != 0) { 1209 for (i = 0; i < sensitive_data.nkeys; i++) { 1210 if (sensitive_data.keys[i] != NULL) { 1211 /* Destroys contents safely */ 1212 debug3("clear hostkey %d", i); 1213 key_free(sensitive_data.keys[i]); 1214 sensitive_data.keys[i] = NULL; 1215 } 1216 } 1217 free(sensitive_data.keys); 1218 } 1219 for (i = 0; i < options.num_identity_files; i++) { 1220 free(options.identity_files[i]); 1221 options.identity_files[i] = NULL; 1222 if (options.identity_keys[i]) { 1223 key_free(options.identity_keys[i]); 1224 options.identity_keys[i] = NULL; 1225 } 1226 } 1227 1228 exit_status = compat20 ? ssh_session2() : ssh_session(); 1229 packet_close(); 1230 1231 if (options.control_path != NULL && muxserver_sock != -1) 1232 unlink(options.control_path); 1233 1234 /* Kill ProxyCommand if it is running. */ 1235 ssh_kill_proxy_command(); 1236 1237 return exit_status; 1238 } 1239 1240 static void 1241 control_persist_detach(void) 1242 { 1243 pid_t pid; 1244 int devnull; 1245 1246 debug("%s: backgrounding master process", __func__); 1247 1248 /* 1249 * master (current process) into the background, and make the 1250 * foreground process a client of the backgrounded master. 1251 */ 1252 switch ((pid = fork())) { 1253 case -1: 1254 fatal("%s: fork: %s", __func__, strerror(errno)); 1255 case 0: 1256 /* Child: master process continues mainloop */ 1257 break; 1258 default: 1259 /* Parent: set up mux slave to connect to backgrounded master */ 1260 debug2("%s: background process is %ld", __func__, (long)pid); 1261 stdin_null_flag = ostdin_null_flag; 1262 options.request_tty = orequest_tty; 1263 tty_flag = otty_flag; 1264 close(muxserver_sock); 1265 muxserver_sock = -1; 1266 options.control_master = SSHCTL_MASTER_NO; 1267 muxclient(options.control_path); 1268 /* muxclient() doesn't return on success. */ 1269 fatal("Failed to connect to new control master"); 1270 } 1271 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { 1272 error("%s: open(\"/dev/null\"): %s", __func__, 1273 strerror(errno)); 1274 } else { 1275 if (dup2(devnull, STDIN_FILENO) == -1 || 1276 dup2(devnull, STDOUT_FILENO) == -1) 1277 error("%s: dup2: %s", __func__, strerror(errno)); 1278 if (devnull > STDERR_FILENO) 1279 close(devnull); 1280 } 1281 daemon(1, 1); 1282 setproctitle("%s [mux]", options.control_path); 1283 } 1284 1285 /* Do fork() after authentication. Used by "ssh -f" */ 1286 static void 1287 fork_postauth(void) 1288 { 1289 if (need_controlpersist_detach) 1290 control_persist_detach(); 1291 debug("forking to background"); 1292 fork_after_authentication_flag = 0; 1293 if (daemon(1, 1) < 0) 1294 fatal("daemon() failed: %.200s", strerror(errno)); 1295 } 1296 1297 /* Callback for remote forward global requests */ 1298 static void 1299 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 1300 { 1301 struct Forward *rfwd = (struct Forward *)ctxt; 1302 1303 /* XXX verbose() on failure? */ 1304 debug("remote forward %s for: listen %s%s%d, connect %s:%d", 1305 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 1306 rfwd->listen_path ? rfwd->listen_path : 1307 rfwd->listen_host ? rfwd->listen_host : "", 1308 (rfwd->listen_path || rfwd->listen_host) ? ":" : "", 1309 rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path : 1310 rfwd->connect_host, rfwd->connect_port); 1311 if (rfwd->listen_path == NULL && rfwd->listen_port == 0) { 1312 if (type == SSH2_MSG_REQUEST_SUCCESS) { 1313 rfwd->allocated_port = packet_get_int(); 1314 logit("Allocated port %u for remote forward to %s:%d", 1315 rfwd->allocated_port, 1316 rfwd->connect_host, rfwd->connect_port); 1317 channel_update_permitted_opens(rfwd->handle, 1318 rfwd->allocated_port); 1319 } else { 1320 channel_update_permitted_opens(rfwd->handle, -1); 1321 } 1322 } 1323 1324 if (type == SSH2_MSG_REQUEST_FAILURE) { 1325 if (options.exit_on_forward_failure) { 1326 if (rfwd->listen_path != NULL) 1327 fatal("Error: remote port forwarding failed " 1328 "for listen path %s", rfwd->listen_path); 1329 else 1330 fatal("Error: remote port forwarding failed " 1331 "for listen port %d", rfwd->listen_port); 1332 } else { 1333 if (rfwd->listen_path != NULL) 1334 logit("Warning: remote port forwarding failed " 1335 "for listen path %s", rfwd->listen_path); 1336 else 1337 logit("Warning: remote port forwarding failed " 1338 "for listen port %d", rfwd->listen_port); 1339 } 1340 } 1341 if (++remote_forward_confirms_received == options.num_remote_forwards) { 1342 debug("All remote forwarding requests processed"); 1343 if (fork_after_authentication_flag) 1344 fork_postauth(); 1345 } 1346 } 1347 1348 static void 1349 client_cleanup_stdio_fwd(int id, void *arg) 1350 { 1351 debug("stdio forwarding: done"); 1352 cleanup_exit(0); 1353 } 1354 1355 static void 1356 ssh_stdio_confirm(int id, int success, void *arg) 1357 { 1358 if (!success) 1359 fatal("stdio forwarding failed"); 1360 } 1361 1362 static void 1363 ssh_init_stdio_forwarding(void) 1364 { 1365 Channel *c; 1366 int in, out; 1367 1368 if (stdio_forward_host == NULL) 1369 return; 1370 if (!compat20) 1371 fatal("stdio forwarding require Protocol 2"); 1372 1373 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port); 1374 1375 if ((in = dup(STDIN_FILENO)) < 0 || 1376 (out = dup(STDOUT_FILENO)) < 0) 1377 fatal("channel_connect_stdio_fwd: dup() in/out failed"); 1378 if ((c = channel_connect_stdio_fwd(stdio_forward_host, 1379 stdio_forward_port, in, out)) == NULL) 1380 fatal("%s: channel_connect_stdio_fwd failed", __func__); 1381 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0); 1382 channel_register_open_confirm(c->self, ssh_stdio_confirm, NULL); 1383 } 1384 1385 static void 1386 ssh_init_forwarding(void) 1387 { 1388 int success = 0; 1389 int i; 1390 1391 /* Initiate local TCP/IP port forwardings. */ 1392 for (i = 0; i < options.num_local_forwards; i++) { 1393 debug("Local connections to %.200s:%d forwarded to remote " 1394 "address %.200s:%d", 1395 (options.local_forwards[i].listen_path != NULL) ? 1396 options.local_forwards[i].listen_path : 1397 (options.local_forwards[i].listen_host == NULL) ? 1398 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") : 1399 options.local_forwards[i].listen_host, 1400 options.local_forwards[i].listen_port, 1401 (options.local_forwards[i].connect_path != NULL) ? 1402 options.local_forwards[i].connect_path : 1403 options.local_forwards[i].connect_host, 1404 options.local_forwards[i].connect_port); 1405 success += channel_setup_local_fwd_listener( 1406 &options.local_forwards[i], &options.fwd_opts); 1407 } 1408 if (i > 0 && success != i && options.exit_on_forward_failure) 1409 fatal("Could not request local forwarding."); 1410 if (i > 0 && success == 0) 1411 error("Could not request local forwarding."); 1412 1413 /* Initiate remote TCP/IP port forwardings. */ 1414 for (i = 0; i < options.num_remote_forwards; i++) { 1415 debug("Remote connections from %.200s:%d forwarded to " 1416 "local address %.200s:%d", 1417 (options.remote_forwards[i].listen_path != NULL) ? 1418 options.remote_forwards[i].listen_path : 1419 (options.remote_forwards[i].listen_host == NULL) ? 1420 "LOCALHOST" : options.remote_forwards[i].listen_host, 1421 options.remote_forwards[i].listen_port, 1422 (options.remote_forwards[i].connect_path != NULL) ? 1423 options.remote_forwards[i].connect_path : 1424 options.remote_forwards[i].connect_host, 1425 options.remote_forwards[i].connect_port); 1426 options.remote_forwards[i].handle = 1427 channel_request_remote_forwarding( 1428 &options.remote_forwards[i]); 1429 if (options.remote_forwards[i].handle < 0) { 1430 if (options.exit_on_forward_failure) 1431 fatal("Could not request remote forwarding."); 1432 else 1433 logit("Warning: Could not request remote " 1434 "forwarding."); 1435 } else { 1436 client_register_global_confirm(ssh_confirm_remote_forward, 1437 &options.remote_forwards[i]); 1438 } 1439 } 1440 1441 /* Initiate tunnel forwarding. */ 1442 if (options.tun_open != SSH_TUNMODE_NO) { 1443 if (client_request_tun_fwd(options.tun_open, 1444 options.tun_local, options.tun_remote) == -1) { 1445 if (options.exit_on_forward_failure) 1446 fatal("Could not request tunnel forwarding."); 1447 else 1448 error("Could not request tunnel forwarding."); 1449 } 1450 } 1451 } 1452 1453 static void 1454 check_agent_present(void) 1455 { 1456 if (options.forward_agent) { 1457 /* Clear agent forwarding if we don't have an agent. */ 1458 if (!ssh_agent_present()) 1459 options.forward_agent = 0; 1460 } 1461 } 1462 1463 static int 1464 ssh_session(void) 1465 { 1466 int type; 1467 int interactive = 0; 1468 int have_tty = 0; 1469 struct winsize ws; 1470 char *cp; 1471 const char *display; 1472 1473 /* Enable compression if requested. */ 1474 if (options.compression) { 1475 debug("Requesting compression at level %d.", 1476 options.compression_level); 1477 1478 if (options.compression_level < 1 || 1479 options.compression_level > 9) 1480 fatal("Compression level must be from 1 (fast) to " 1481 "9 (slow, best)."); 1482 1483 /* Send the request. */ 1484 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 1485 packet_put_int(options.compression_level); 1486 packet_send(); 1487 packet_write_wait(); 1488 type = packet_read(); 1489 if (type == SSH_SMSG_SUCCESS) 1490 packet_start_compression(options.compression_level); 1491 else if (type == SSH_SMSG_FAILURE) 1492 logit("Warning: Remote host refused compression."); 1493 else 1494 packet_disconnect("Protocol error waiting for " 1495 "compression response."); 1496 } 1497 /* Allocate a pseudo tty if appropriate. */ 1498 if (tty_flag) { 1499 debug("Requesting pty."); 1500 1501 /* Start the packet. */ 1502 packet_start(SSH_CMSG_REQUEST_PTY); 1503 1504 /* Store TERM in the packet. There is no limit on the 1505 length of the string. */ 1506 cp = getenv("TERM"); 1507 if (!cp) 1508 cp = ""; 1509 packet_put_cstring(cp); 1510 1511 /* Store window size in the packet. */ 1512 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1513 memset(&ws, 0, sizeof(ws)); 1514 packet_put_int((u_int)ws.ws_row); 1515 packet_put_int((u_int)ws.ws_col); 1516 packet_put_int((u_int)ws.ws_xpixel); 1517 packet_put_int((u_int)ws.ws_ypixel); 1518 1519 /* Store tty modes in the packet. */ 1520 tty_make_modes(fileno(stdin), NULL); 1521 1522 /* Send the packet, and wait for it to leave. */ 1523 packet_send(); 1524 packet_write_wait(); 1525 1526 /* Read response from the server. */ 1527 type = packet_read(); 1528 if (type == SSH_SMSG_SUCCESS) { 1529 interactive = 1; 1530 have_tty = 1; 1531 } else if (type == SSH_SMSG_FAILURE) 1532 logit("Warning: Remote host failed or refused to " 1533 "allocate a pseudo tty."); 1534 else 1535 packet_disconnect("Protocol error waiting for pty " 1536 "request response."); 1537 } 1538 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1539 display = getenv("DISPLAY"); 1540 if (options.forward_x11 && display != NULL) { 1541 char *proto, *data; 1542 /* Get reasonable local authentication information. */ 1543 client_x11_get_proto(display, options.xauth_location, 1544 options.forward_x11_trusted, 1545 options.forward_x11_timeout, 1546 &proto, &data); 1547 /* Request forwarding with authentication spoofing. */ 1548 debug("Requesting X11 forwarding with authentication " 1549 "spoofing."); 1550 x11_request_forwarding_with_spoofing(0, display, proto, 1551 data, 0); 1552 /* Read response from the server. */ 1553 type = packet_read(); 1554 if (type == SSH_SMSG_SUCCESS) { 1555 interactive = 1; 1556 } else if (type == SSH_SMSG_FAILURE) { 1557 logit("Warning: Remote host denied X11 forwarding."); 1558 } else { 1559 packet_disconnect("Protocol error waiting for X11 " 1560 "forwarding"); 1561 } 1562 } 1563 /* Tell the packet module whether this is an interactive session. */ 1564 packet_set_interactive(interactive, 1565 options.ip_qos_interactive, options.ip_qos_bulk); 1566 1567 /* Request authentication agent forwarding if appropriate. */ 1568 check_agent_present(); 1569 1570 if (options.forward_agent) { 1571 debug("Requesting authentication agent forwarding."); 1572 auth_request_forwarding(); 1573 1574 /* Read response from the server. */ 1575 type = packet_read(); 1576 packet_check_eom(); 1577 if (type != SSH_SMSG_SUCCESS) 1578 logit("Warning: Remote host denied authentication agent forwarding."); 1579 } 1580 1581 /* Initiate port forwardings. */ 1582 ssh_init_stdio_forwarding(); 1583 ssh_init_forwarding(); 1584 1585 /* Execute a local command */ 1586 if (options.local_command != NULL && 1587 options.permit_local_command) 1588 ssh_local_cmd(options.local_command); 1589 1590 /* 1591 * If requested and we are not interested in replies to remote 1592 * forwarding requests, then let ssh continue in the background. 1593 */ 1594 if (fork_after_authentication_flag) { 1595 if (options.exit_on_forward_failure && 1596 options.num_remote_forwards > 0) { 1597 debug("deferring postauth fork until remote forward " 1598 "confirmation received"); 1599 } else 1600 fork_postauth(); 1601 } 1602 1603 /* 1604 * If a command was specified on the command line, execute the 1605 * command now. Otherwise request the server to start a shell. 1606 */ 1607 if (buffer_len(&command) > 0) { 1608 int len = buffer_len(&command); 1609 if (len > 900) 1610 len = 900; 1611 debug("Sending command: %.*s", len, 1612 (u_char *)buffer_ptr(&command)); 1613 packet_start(SSH_CMSG_EXEC_CMD); 1614 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1615 packet_send(); 1616 packet_write_wait(); 1617 } else { 1618 debug("Requesting shell."); 1619 packet_start(SSH_CMSG_EXEC_SHELL); 1620 packet_send(); 1621 packet_write_wait(); 1622 } 1623 1624 /* Enter the interactive session. */ 1625 return client_loop(have_tty, tty_flag ? 1626 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1627 } 1628 1629 /* request pty/x11/agent/tcpfwd/shell for channel */ 1630 static void 1631 ssh_session2_setup(int id, int success, void *arg) 1632 { 1633 extern char **environ; 1634 const char *display; 1635 int interactive = tty_flag; 1636 1637 if (!success) 1638 return; /* No need for error message, channels code sens one */ 1639 1640 display = getenv("DISPLAY"); 1641 if (options.forward_x11 && display != NULL) { 1642 char *proto, *data; 1643 /* Get reasonable local authentication information. */ 1644 client_x11_get_proto(display, options.xauth_location, 1645 options.forward_x11_trusted, 1646 options.forward_x11_timeout, &proto, &data); 1647 /* Request forwarding with authentication spoofing. */ 1648 debug("Requesting X11 forwarding with authentication " 1649 "spoofing."); 1650 x11_request_forwarding_with_spoofing(id, display, proto, 1651 data, 1); 1652 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); 1653 /* XXX exit_on_forward_failure */ 1654 interactive = 1; 1655 } 1656 1657 check_agent_present(); 1658 if (options.forward_agent) { 1659 debug("Requesting authentication agent forwarding."); 1660 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1661 packet_send(); 1662 } 1663 1664 /* Tell the packet module whether this is an interactive session. */ 1665 packet_set_interactive(interactive, 1666 options.ip_qos_interactive, options.ip_qos_bulk); 1667 1668 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1669 NULL, fileno(stdin), &command, environ); 1670 } 1671 1672 /* open new channel for a session */ 1673 static int 1674 ssh_session2_open(void) 1675 { 1676 Channel *c; 1677 int window, packetmax, in, out, err; 1678 1679 if (stdin_null_flag) { 1680 in = open(_PATH_DEVNULL, O_RDONLY); 1681 } else { 1682 in = dup(STDIN_FILENO); 1683 } 1684 out = dup(STDOUT_FILENO); 1685 err = dup(STDERR_FILENO); 1686 1687 if (in < 0 || out < 0 || err < 0) 1688 fatal("dup() in/out/err failed"); 1689 1690 /* enable nonblocking unless tty */ 1691 if (!isatty(in)) 1692 set_nonblock(in); 1693 if (!isatty(out)) 1694 set_nonblock(out); 1695 if (!isatty(err)) 1696 set_nonblock(err); 1697 1698 window = CHAN_SES_WINDOW_DEFAULT; 1699 packetmax = CHAN_SES_PACKET_DEFAULT; 1700 if (tty_flag) { 1701 window >>= 1; 1702 packetmax >>= 1; 1703 } 1704 c = channel_new( 1705 "session", SSH_CHANNEL_OPENING, in, out, err, 1706 window, packetmax, CHAN_EXTENDED_WRITE, 1707 "client-session", /*nonblock*/0); 1708 1709 debug3("ssh_session2_open: channel_new: %d", c->self); 1710 1711 channel_send_open(c->self); 1712 if (!no_shell_flag) 1713 channel_register_open_confirm(c->self, 1714 ssh_session2_setup, NULL); 1715 1716 return c->self; 1717 } 1718 1719 static int 1720 ssh_session2(void) 1721 { 1722 int id = -1; 1723 1724 /* XXX should be pre-session */ 1725 if (!options.control_persist) 1726 ssh_init_stdio_forwarding(); 1727 ssh_init_forwarding(); 1728 1729 /* Start listening for multiplex clients */ 1730 muxserver_listen(); 1731 1732 /* 1733 * If we are in control persist mode and have a working mux listen 1734 * socket, then prepare to background ourselves and have a foreground 1735 * client attach as a control slave. 1736 * NB. we must save copies of the flags that we override for 1737 * the backgrounding, since we defer attachment of the slave until 1738 * after the connection is fully established (in particular, 1739 * async rfwd replies have been received for ExitOnForwardFailure). 1740 */ 1741 if (options.control_persist && muxserver_sock != -1) { 1742 ostdin_null_flag = stdin_null_flag; 1743 ono_shell_flag = no_shell_flag; 1744 orequest_tty = options.request_tty; 1745 otty_flag = tty_flag; 1746 stdin_null_flag = 1; 1747 no_shell_flag = 1; 1748 tty_flag = 0; 1749 if (!fork_after_authentication_flag) 1750 need_controlpersist_detach = 1; 1751 fork_after_authentication_flag = 1; 1752 } 1753 /* 1754 * ControlPersist mux listen socket setup failed, attempt the 1755 * stdio forward setup that we skipped earlier. 1756 */ 1757 if (options.control_persist && muxserver_sock == -1) 1758 ssh_init_stdio_forwarding(); 1759 1760 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1761 id = ssh_session2_open(); 1762 else { 1763 packet_set_interactive( 1764 options.control_master == SSHCTL_MASTER_NO, 1765 options.ip_qos_interactive, options.ip_qos_bulk); 1766 } 1767 1768 /* If we don't expect to open a new session, then disallow it */ 1769 if (options.control_master == SSHCTL_MASTER_NO && 1770 (datafellows & SSH_NEW_OPENSSH)) { 1771 debug("Requesting no-more-sessions@openssh.com"); 1772 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1773 packet_put_cstring("no-more-sessions@openssh.com"); 1774 packet_put_char(0); 1775 packet_send(); 1776 } 1777 1778 /* Execute a local command */ 1779 if (options.local_command != NULL && 1780 options.permit_local_command) 1781 ssh_local_cmd(options.local_command); 1782 1783 /* 1784 * If requested and we are not interested in replies to remote 1785 * forwarding requests, then let ssh continue in the background. 1786 */ 1787 if (fork_after_authentication_flag) { 1788 if (options.exit_on_forward_failure && 1789 options.num_remote_forwards > 0) { 1790 debug("deferring postauth fork until remote forward " 1791 "confirmation received"); 1792 } else 1793 fork_postauth(); 1794 } 1795 1796 if (options.use_roaming) 1797 request_roaming(); 1798 1799 return client_loop(tty_flag, tty_flag ? 1800 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1801 } 1802 1803 static void 1804 load_public_identity_files(void) 1805 { 1806 char *filename, *cp, thishost[NI_MAXHOST]; 1807 char *pwdir = NULL, *pwname = NULL; 1808 int i = 0; 1809 Key *public; 1810 struct passwd *pw; 1811 u_int n_ids; 1812 char *identity_files[SSH_MAX_IDENTITY_FILES]; 1813 Key *identity_keys[SSH_MAX_IDENTITY_FILES]; 1814 #ifdef ENABLE_PKCS11 1815 Key **keys; 1816 int nkeys; 1817 #endif /* PKCS11 */ 1818 1819 n_ids = 0; 1820 memset(identity_files, 0, sizeof(identity_files)); 1821 memset(identity_keys, 0, sizeof(identity_keys)); 1822 1823 #ifdef ENABLE_PKCS11 1824 if (options.pkcs11_provider != NULL && 1825 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1826 (pkcs11_init(!options.batch_mode) == 0) && 1827 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL, 1828 &keys)) > 0) { 1829 for (i = 0; i < nkeys; i++) { 1830 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1831 key_free(keys[i]); 1832 continue; 1833 } 1834 identity_keys[n_ids] = keys[i]; 1835 identity_files[n_ids] = 1836 xstrdup(options.pkcs11_provider); /* XXX */ 1837 n_ids++; 1838 } 1839 free(keys); 1840 } 1841 #endif /* ENABLE_PKCS11 */ 1842 if ((pw = getpwuid(original_real_uid)) == NULL) 1843 fatal("load_public_identity_files: getpwuid failed"); 1844 pwname = xstrdup(pw->pw_name); 1845 pwdir = xstrdup(pw->pw_dir); 1846 if (gethostname(thishost, sizeof(thishost)) == -1) 1847 fatal("load_public_identity_files: gethostname: %s", 1848 strerror(errno)); 1849 for (i = 0; i < options.num_identity_files; i++) { 1850 if (n_ids >= SSH_MAX_IDENTITY_FILES || 1851 strcasecmp(options.identity_files[i], "none") == 0) { 1852 free(options.identity_files[i]); 1853 continue; 1854 } 1855 cp = tilde_expand_filename(options.identity_files[i], 1856 original_real_uid); 1857 filename = percent_expand(cp, "d", pwdir, 1858 "u", pwname, "l", thishost, "h", host, 1859 "r", options.user, (char *)NULL); 1860 free(cp); 1861 public = key_load_public(filename, NULL); 1862 debug("identity file %s type %d", filename, 1863 public ? public->type : -1); 1864 free(options.identity_files[i]); 1865 identity_files[n_ids] = filename; 1866 identity_keys[n_ids] = public; 1867 1868 if (++n_ids >= SSH_MAX_IDENTITY_FILES) 1869 continue; 1870 1871 /* Try to add the certificate variant too */ 1872 xasprintf(&cp, "%s-cert", filename); 1873 public = key_load_public(cp, NULL); 1874 debug("identity file %s type %d", cp, 1875 public ? public->type : -1); 1876 if (public == NULL) { 1877 free(cp); 1878 continue; 1879 } 1880 if (!key_is_cert(public)) { 1881 debug("%s: key %s type %s is not a certificate", 1882 __func__, cp, key_type(public)); 1883 key_free(public); 1884 free(cp); 1885 continue; 1886 } 1887 identity_keys[n_ids] = public; 1888 /* point to the original path, most likely the private key */ 1889 identity_files[n_ids] = xstrdup(filename); 1890 n_ids++; 1891 } 1892 options.num_identity_files = n_ids; 1893 memcpy(options.identity_files, identity_files, sizeof(identity_files)); 1894 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys)); 1895 1896 explicit_bzero(pwname, strlen(pwname)); 1897 free(pwname); 1898 explicit_bzero(pwdir, strlen(pwdir)); 1899 free(pwdir); 1900 } 1901 1902 static void 1903 main_sigchld_handler(int sig) 1904 { 1905 int save_errno = errno; 1906 pid_t pid; 1907 int status; 1908 1909 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 1910 (pid < 0 && errno == EINTR)) 1911 ; 1912 1913 signal(sig, main_sigchld_handler); 1914 errno = save_errno; 1915 } 1916