1 /* $OpenBSD: ssh.c,v 1.402 2014/04/29 18:01:49 markus 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 "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 "readconf.h" 90 #include "sshconnect.h" 91 #include "misc.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; 180 181 182 /* 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 [-1246AaCfgKkMNnqsTtVvXxYy] [-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(struct passwd *pw) 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, &options, 381 SSHCONF_USERCONF)) 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, &options, 389 SSHCONF_CHECKPERM|SSHCONF_USERCONF); 390 391 /* Read systemwide configuration file after user config. */ 392 (void)read_config_file(_PATH_HOST_CONFIG_FILE, pw, host, 393 &options, 0); 394 } 395 } 396 397 /* 398 * Main program for the ssh client. 399 */ 400 int 401 main(int ac, char **av) 402 { 403 int i, r, opt, exit_status, use_syslog; 404 char *p, *cp, *line, *argv0, buf[MAXPATHLEN], *host_arg, *logfile; 405 char thishost[NI_MAXHOST], shorthost[NI_MAXHOST], portstr[NI_MAXSERV]; 406 char cname[NI_MAXHOST]; 407 struct stat st; 408 struct passwd *pw; 409 int timeout_ms; 410 extern int optind, optreset; 411 extern char *optarg; 412 Forward fwd; 413 struct addrinfo *addrs = NULL; 414 415 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 416 sanitise_stdfd(); 417 418 /* 419 * Discard other fds that are hanging around. These can cause problem 420 * with backgrounded ssh processes started by ControlPersist. 421 */ 422 closefrom(STDERR_FILENO + 1); 423 424 /* 425 * Save the original real uid. It will be needed later (uid-swapping 426 * may clobber the real uid). 427 */ 428 original_real_uid = getuid(); 429 original_effective_uid = geteuid(); 430 431 /* 432 * Use uid-swapping to give up root privileges for the duration of 433 * option processing. We will re-instantiate the rights when we are 434 * ready to create the privileged port, and will permanently drop 435 * them when the port has been created (actually, when the connection 436 * has been made, as we may need to create the port several times). 437 */ 438 PRIV_END; 439 440 /* If we are installed setuid root be careful to not drop core. */ 441 if (original_real_uid != original_effective_uid) { 442 struct rlimit rlim; 443 rlim.rlim_cur = rlim.rlim_max = 0; 444 if (setrlimit(RLIMIT_CORE, &rlim) < 0) 445 fatal("setrlimit failed: %.100s", strerror(errno)); 446 } 447 /* Get user data. */ 448 pw = getpwuid(original_real_uid); 449 if (!pw) { 450 logit("No user exists for uid %lu", (u_long)original_real_uid); 451 exit(255); 452 } 453 /* Take a copy of the returned structure. */ 454 pw = pwcopy(pw); 455 456 /* 457 * Set our umask to something reasonable, as some files are created 458 * with the default umask. This will make them world-readable but 459 * writable only by the owner, which is ok for all files for which we 460 * don't set the modes explicitly. 461 */ 462 umask(022); 463 464 /* 465 * Initialize option structure to indicate that no values have been 466 * set. 467 */ 468 initialize_options(&options); 469 470 /* Parse command-line arguments. */ 471 host = NULL; 472 use_syslog = 0; 473 logfile = NULL; 474 argv0 = av[0]; 475 476 again: 477 while ((opt = getopt(ac, av, "1246ab:c:e:fgi:kl:m:no:p:qstvx" 478 "ACD:E:F:I:KL:MNO:PQ:R:S:TVw:W:XYy")) != -1) { 479 switch (opt) { 480 case '1': 481 options.protocol = SSH_PROTO_1; 482 break; 483 case '2': 484 options.protocol = SSH_PROTO_2; 485 break; 486 case '4': 487 options.address_family = AF_INET; 488 break; 489 case '6': 490 options.address_family = AF_INET6; 491 break; 492 case 'n': 493 stdin_null_flag = 1; 494 break; 495 case 'f': 496 fork_after_authentication_flag = 1; 497 stdin_null_flag = 1; 498 break; 499 case 'x': 500 options.forward_x11 = 0; 501 break; 502 case 'X': 503 options.forward_x11 = 1; 504 break; 505 case 'y': 506 use_syslog = 1; 507 break; 508 case 'E': 509 logfile = xstrdup(optarg); 510 break; 511 case 'Y': 512 options.forward_x11 = 1; 513 options.forward_x11_trusted = 1; 514 break; 515 case 'g': 516 options.gateway_ports = 1; 517 break; 518 case 'O': 519 if (stdio_forward_host != NULL) 520 fatal("Cannot specify multiplexing " 521 "command with -W"); 522 else if (muxclient_command != 0) 523 fatal("Multiplexing command already specified"); 524 if (strcmp(optarg, "check") == 0) 525 muxclient_command = SSHMUX_COMMAND_ALIVE_CHECK; 526 else if (strcmp(optarg, "forward") == 0) 527 muxclient_command = SSHMUX_COMMAND_FORWARD; 528 else if (strcmp(optarg, "exit") == 0) 529 muxclient_command = SSHMUX_COMMAND_TERMINATE; 530 else if (strcmp(optarg, "stop") == 0) 531 muxclient_command = SSHMUX_COMMAND_STOP; 532 else if (strcmp(optarg, "cancel") == 0) 533 muxclient_command = SSHMUX_COMMAND_CANCEL_FWD; 534 else 535 fatal("Invalid multiplex command."); 536 break; 537 case 'P': /* deprecated */ 538 options.use_privileged_port = 0; 539 break; 540 case 'Q': 541 cp = NULL; 542 if (strcmp(optarg, "cipher") == 0) 543 cp = cipher_alg_list('\n', 0); 544 else if (strcmp(optarg, "cipher-auth") == 0) 545 cp = cipher_alg_list('\n', 1); 546 else if (strcmp(optarg, "mac") == 0) 547 cp = mac_alg_list('\n'); 548 else if (strcmp(optarg, "kex") == 0) 549 cp = kex_alg_list('\n'); 550 else if (strcmp(optarg, "key") == 0) 551 cp = key_alg_list(0, 0); 552 else if (strcmp(optarg, "key-cert") == 0) 553 cp = key_alg_list(1, 0); 554 else if (strcmp(optarg, "key-plain") == 0) 555 cp = key_alg_list(0, 1); 556 if (cp == NULL) 557 fatal("Unsupported query \"%s\"", optarg); 558 printf("%s\n", cp); 559 free(cp); 560 exit(0); 561 break; 562 case 'a': 563 options.forward_agent = 0; 564 break; 565 case 'A': 566 options.forward_agent = 1; 567 break; 568 case 'k': 569 options.gss_deleg_creds = 0; 570 break; 571 case 'K': 572 options.gss_authentication = 1; 573 options.gss_deleg_creds = 1; 574 break; 575 case 'i': 576 if (stat(optarg, &st) < 0) { 577 fprintf(stderr, "Warning: Identity file %s " 578 "not accessible: %s.\n", optarg, 579 strerror(errno)); 580 break; 581 } 582 add_identity_file(&options, NULL, optarg, 1); 583 break; 584 case 'I': 585 #ifdef ENABLE_PKCS11 586 options.pkcs11_provider = xstrdup(optarg); 587 #else 588 fprintf(stderr, "no support for PKCS#11.\n"); 589 #endif 590 break; 591 case 't': 592 if (options.request_tty == REQUEST_TTY_YES) 593 options.request_tty = REQUEST_TTY_FORCE; 594 else 595 options.request_tty = REQUEST_TTY_YES; 596 break; 597 case 'v': 598 if (debug_flag == 0) { 599 debug_flag = 1; 600 options.log_level = SYSLOG_LEVEL_DEBUG1; 601 } else { 602 if (options.log_level < SYSLOG_LEVEL_DEBUG3) 603 options.log_level++; 604 } 605 break; 606 case 'V': 607 fprintf(stderr, "%s, %s\n", 608 SSH_VERSION, 609 #ifdef WITH_OPENSSL 610 SSLeay_version(SSLEAY_VERSION) 611 #else 612 "without OpenSSL" 613 #endif 614 ); 615 if (opt == 'V') 616 exit(0); 617 break; 618 case 'w': 619 if (options.tun_open == -1) 620 options.tun_open = SSH_TUNMODE_DEFAULT; 621 options.tun_local = a2tun(optarg, &options.tun_remote); 622 if (options.tun_local == SSH_TUNID_ERR) { 623 fprintf(stderr, 624 "Bad tun device '%s'\n", optarg); 625 exit(255); 626 } 627 break; 628 case 'W': 629 if (stdio_forward_host != NULL) 630 fatal("stdio forward already specified"); 631 if (muxclient_command != 0) 632 fatal("Cannot specify stdio forward with -O"); 633 if (parse_forward(&fwd, optarg, 1, 0)) { 634 stdio_forward_host = fwd.listen_host; 635 stdio_forward_port = fwd.listen_port; 636 free(fwd.connect_host); 637 } else { 638 fprintf(stderr, 639 "Bad stdio forwarding specification '%s'\n", 640 optarg); 641 exit(255); 642 } 643 options.request_tty = REQUEST_TTY_NO; 644 no_shell_flag = 1; 645 options.clear_forwardings = 1; 646 options.exit_on_forward_failure = 1; 647 break; 648 case 'q': 649 options.log_level = SYSLOG_LEVEL_QUIET; 650 break; 651 case 'e': 652 if (optarg[0] == '^' && optarg[2] == 0 && 653 (u_char) optarg[1] >= 64 && 654 (u_char) optarg[1] < 128) 655 options.escape_char = (u_char) optarg[1] & 31; 656 else if (strlen(optarg) == 1) 657 options.escape_char = (u_char) optarg[0]; 658 else if (strcmp(optarg, "none") == 0) 659 options.escape_char = SSH_ESCAPECHAR_NONE; 660 else { 661 fprintf(stderr, "Bad escape character '%s'.\n", 662 optarg); 663 exit(255); 664 } 665 break; 666 case 'c': 667 if (ciphers_valid(optarg)) { 668 /* SSH2 only */ 669 options.ciphers = xstrdup(optarg); 670 options.cipher = SSH_CIPHER_INVALID; 671 } else { 672 /* SSH1 only */ 673 options.cipher = cipher_number(optarg); 674 if (options.cipher == -1) { 675 fprintf(stderr, 676 "Unknown cipher type '%s'\n", 677 optarg); 678 exit(255); 679 } 680 if (options.cipher == SSH_CIPHER_3DES) 681 options.ciphers = "3des-cbc"; 682 else if (options.cipher == SSH_CIPHER_BLOWFISH) 683 options.ciphers = "blowfish-cbc"; 684 else 685 options.ciphers = (char *)-1; 686 } 687 break; 688 case 'm': 689 if (mac_valid(optarg)) 690 options.macs = xstrdup(optarg); 691 else { 692 fprintf(stderr, "Unknown mac type '%s'\n", 693 optarg); 694 exit(255); 695 } 696 break; 697 case 'M': 698 if (options.control_master == SSHCTL_MASTER_YES) 699 options.control_master = SSHCTL_MASTER_ASK; 700 else 701 options.control_master = SSHCTL_MASTER_YES; 702 break; 703 case 'p': 704 options.port = a2port(optarg); 705 if (options.port <= 0) { 706 fprintf(stderr, "Bad port '%s'\n", optarg); 707 exit(255); 708 } 709 break; 710 case 'l': 711 options.user = optarg; 712 break; 713 714 case 'L': 715 if (parse_forward(&fwd, optarg, 0, 0)) 716 add_local_forward(&options, &fwd); 717 else { 718 fprintf(stderr, 719 "Bad local forwarding specification '%s'\n", 720 optarg); 721 exit(255); 722 } 723 break; 724 725 case 'R': 726 if (parse_forward(&fwd, optarg, 0, 1)) { 727 add_remote_forward(&options, &fwd); 728 } else { 729 fprintf(stderr, 730 "Bad remote forwarding specification " 731 "'%s'\n", optarg); 732 exit(255); 733 } 734 break; 735 736 case 'D': 737 if (parse_forward(&fwd, optarg, 1, 0)) { 738 add_local_forward(&options, &fwd); 739 } else { 740 fprintf(stderr, 741 "Bad dynamic forwarding specification " 742 "'%s'\n", optarg); 743 exit(255); 744 } 745 break; 746 747 case 'C': 748 options.compression = 1; 749 break; 750 case 'N': 751 no_shell_flag = 1; 752 options.request_tty = REQUEST_TTY_NO; 753 break; 754 case 'T': 755 options.request_tty = REQUEST_TTY_NO; 756 break; 757 case 'o': 758 line = xstrdup(optarg); 759 if (process_config_line(&options, pw, host ? host : "", 760 line, "command-line", 0, NULL, SSHCONF_USERCONF) 761 != 0) 762 exit(255); 763 free(line); 764 break; 765 case 's': 766 subsystem_flag = 1; 767 break; 768 case 'S': 769 if (options.control_path != NULL) 770 free(options.control_path); 771 options.control_path = xstrdup(optarg); 772 break; 773 case 'b': 774 options.bind_address = optarg; 775 break; 776 case 'F': 777 config = optarg; 778 break; 779 default: 780 usage(); 781 } 782 } 783 784 ac -= optind; 785 av += optind; 786 787 if (ac > 0 && !host) { 788 if (strrchr(*av, '@')) { 789 p = xstrdup(*av); 790 cp = strrchr(p, '@'); 791 if (cp == NULL || cp == p) 792 usage(); 793 options.user = p; 794 *cp = '\0'; 795 host = xstrdup(++cp); 796 } else 797 host = xstrdup(*av); 798 if (ac > 1) { 799 optind = optreset = 1; 800 goto again; 801 } 802 ac--, av++; 803 } 804 805 /* Check that we got a host name. */ 806 if (!host) 807 usage(); 808 809 host_arg = xstrdup(host); 810 811 #ifdef WITH_OPENSSL 812 OpenSSL_add_all_algorithms(); 813 ERR_load_crypto_strings(); 814 #endif 815 816 /* Initialize the command to execute on remote host. */ 817 buffer_init(&command); 818 819 /* 820 * Save the command to execute on the remote host in a buffer. There 821 * is no limit on the length of the command, except by the maximum 822 * packet size. Also sets the tty flag if there is no command. 823 */ 824 if (!ac) { 825 /* No command specified - execute shell on a tty. */ 826 if (subsystem_flag) { 827 fprintf(stderr, 828 "You must specify a subsystem to invoke.\n"); 829 usage(); 830 } 831 } else { 832 /* A command has been specified. Store it into the buffer. */ 833 for (i = 0; i < ac; i++) { 834 if (i) 835 buffer_append(&command, " ", 1); 836 buffer_append(&command, av[i], strlen(av[i])); 837 } 838 } 839 840 /* Cannot fork to background if no command. */ 841 if (fork_after_authentication_flag && buffer_len(&command) == 0 && 842 !no_shell_flag) 843 fatal("Cannot fork into background without a command " 844 "to execute."); 845 846 /* 847 * Initialize "log" output. Since we are the client all output 848 * goes to stderr unless otherwise specified by -y or -E. 849 */ 850 if (use_syslog && logfile != NULL) 851 fatal("Can't specify both -y and -E"); 852 if (logfile != NULL) { 853 log_redirect_stderr_to(logfile); 854 free(logfile); 855 } 856 log_init(argv0, 857 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level, 858 SYSLOG_FACILITY_USER, !use_syslog); 859 860 if (debug_flag) 861 logit("%s, %s", SSH_VERSION, 862 #ifdef WITH_OPENSSL 863 SSLeay_version(SSLEAY_VERSION) 864 #else 865 "without OpenSSL" 866 #endif 867 ); 868 869 /* Parse the configuration files */ 870 process_config_files(pw); 871 872 /* Hostname canonicalisation needs a few options filled. */ 873 fill_default_options_for_canonicalization(&options); 874 875 /* If the user has replaced the hostname then take it into use now */ 876 if (options.hostname != NULL) { 877 /* NB. Please keep in sync with readconf.c:match_cfg_line() */ 878 cp = percent_expand(options.hostname, 879 "h", host, (char *)NULL); 880 free(host); 881 host = cp; 882 } 883 884 /* If canonicalization requested then try to apply it */ 885 lowercase(host); 886 if (options.canonicalize_hostname != SSH_CANONICALISE_NO) 887 addrs = resolve_canonicalize(&host, options.port); 888 889 /* 890 * If CanonicalizePermittedCNAMEs have been specified but 891 * other canonicalization did not happen (by not being requested 892 * or by failing with fallback) then the hostname may still be changed 893 * as a result of CNAME following. 894 * 895 * Try to resolve the bare hostname name using the system resolver's 896 * usual search rules and then apply the CNAME follow rules. 897 * 898 * Skip the lookup if a ProxyCommand is being used unless the user 899 * has specifically requested canonicalisation for this case via 900 * CanonicalizeHostname=always 901 */ 902 if (addrs == NULL && options.num_permitted_cnames != 0 && 903 (option_clear_or_none(options.proxy_command) || 904 options.canonicalize_hostname == SSH_CANONICALISE_ALWAYS)) { 905 if ((addrs = resolve_host(host, options.port, 1, 906 cname, sizeof(cname))) == NULL) 907 cleanup_exit(255); /* resolve_host logs the error */ 908 check_follow_cname(&host, cname); 909 } 910 911 /* 912 * If the target hostname has changed as a result of canonicalisation 913 * then re-parse the configuration files as new stanzas may match. 914 */ 915 if (strcasecmp(host_arg, host) != 0) { 916 debug("Hostname has changed; re-reading configuration"); 917 process_config_files(pw); 918 } 919 920 /* Fill configuration defaults. */ 921 fill_default_options(&options); 922 923 if (options.port == 0) 924 options.port = default_ssh_port(); 925 channel_set_af(options.address_family); 926 927 /* Tidy and check options */ 928 if (options.host_key_alias != NULL) 929 lowercase(options.host_key_alias); 930 if (options.proxy_command != NULL && 931 strcmp(options.proxy_command, "-") == 0 && 932 options.proxy_use_fdpass) 933 fatal("ProxyCommand=- and ProxyUseFDPass are incompatible"); 934 if (original_effective_uid != 0) 935 options.use_privileged_port = 0; 936 937 /* reinit */ 938 log_init(argv0, options.log_level, SYSLOG_FACILITY_USER, !use_syslog); 939 940 if (options.request_tty == REQUEST_TTY_YES || 941 options.request_tty == REQUEST_TTY_FORCE) 942 tty_flag = 1; 943 944 /* Allocate a tty by default if no command specified. */ 945 if (buffer_len(&command) == 0) 946 tty_flag = options.request_tty != REQUEST_TTY_NO; 947 948 /* Force no tty */ 949 if (options.request_tty == REQUEST_TTY_NO || muxclient_command != 0) 950 tty_flag = 0; 951 /* Do not allocate a tty if stdin is not a tty. */ 952 if ((!isatty(fileno(stdin)) || stdin_null_flag) && 953 options.request_tty != REQUEST_TTY_FORCE) { 954 if (tty_flag) 955 logit("Pseudo-terminal will not be allocated because " 956 "stdin is not a terminal."); 957 tty_flag = 0; 958 } 959 960 if (options.user == NULL) 961 options.user = xstrdup(pw->pw_name); 962 963 if (gethostname(thishost, sizeof(thishost)) == -1) 964 fatal("gethostname: %s", strerror(errno)); 965 strlcpy(shorthost, thishost, sizeof(shorthost)); 966 shorthost[strcspn(thishost, ".")] = '\0'; 967 snprintf(portstr, sizeof(portstr), "%d", options.port); 968 969 if (options.local_command != NULL) { 970 debug3("expanding LocalCommand: %s", options.local_command); 971 cp = options.local_command; 972 options.local_command = percent_expand(cp, "d", pw->pw_dir, 973 "h", host, "l", thishost, "n", host_arg, "r", options.user, 974 "p", portstr, "u", pw->pw_name, "L", shorthost, 975 (char *)NULL); 976 debug3("expanded LocalCommand: %s", options.local_command); 977 free(cp); 978 } 979 980 if (options.control_path != NULL) { 981 cp = tilde_expand_filename(options.control_path, 982 original_real_uid); 983 free(options.control_path); 984 options.control_path = percent_expand(cp, "h", host, 985 "l", thishost, "n", host_arg, "r", options.user, 986 "p", portstr, "u", pw->pw_name, "L", shorthost, 987 (char *)NULL); 988 free(cp); 989 } 990 if (muxclient_command != 0 && options.control_path == NULL) 991 fatal("No ControlPath specified for \"-O\" command"); 992 if (options.control_path != NULL) 993 muxclient(options.control_path); 994 995 /* 996 * If hostname canonicalisation was not enabled, then we may not 997 * have yet resolved the hostname. Do so now. 998 */ 999 if (addrs == NULL && options.proxy_command == NULL) { 1000 if ((addrs = resolve_host(host, options.port, 1, 1001 cname, sizeof(cname))) == NULL) 1002 cleanup_exit(255); /* resolve_host logs the error */ 1003 } 1004 1005 timeout_ms = options.connection_timeout * 1000; 1006 1007 /* Open a connection to the remote host. */ 1008 if (ssh_connect(host, addrs, &hostaddr, options.port, 1009 options.address_family, options.connection_attempts, 1010 &timeout_ms, options.tcp_keep_alive, 1011 options.use_privileged_port) != 0) 1012 exit(255); 1013 1014 if (addrs != NULL) 1015 freeaddrinfo(addrs); 1016 1017 packet_set_timeout(options.server_alive_interval, 1018 options.server_alive_count_max); 1019 1020 if (timeout_ms > 0) 1021 debug3("timeout: %d ms remain after connect", timeout_ms); 1022 1023 /* 1024 * If we successfully made the connection, load the host private key 1025 * in case we will need it later for combined rsa-rhosts 1026 * authentication. This must be done before releasing extra 1027 * privileges, because the file is only readable by root. 1028 * If we cannot access the private keys, load the public keys 1029 * instead and try to execute the ssh-keysign helper instead. 1030 */ 1031 sensitive_data.nkeys = 0; 1032 sensitive_data.keys = NULL; 1033 sensitive_data.external_keysign = 0; 1034 if (options.rhosts_rsa_authentication || 1035 options.hostbased_authentication) { 1036 sensitive_data.nkeys = 9; 1037 sensitive_data.keys = xcalloc(sensitive_data.nkeys, 1038 sizeof(Key)); 1039 1040 PRIV_START; 1041 sensitive_data.keys[0] = key_load_private_type(KEY_RSA1, 1042 _PATH_HOST_KEY_FILE, "", NULL, NULL); 1043 sensitive_data.keys[1] = key_load_private_cert(KEY_DSA, 1044 _PATH_HOST_DSA_KEY_FILE, "", NULL); 1045 sensitive_data.keys[2] = key_load_private_cert(KEY_ECDSA, 1046 _PATH_HOST_ECDSA_KEY_FILE, "", NULL); 1047 sensitive_data.keys[3] = key_load_private_cert(KEY_RSA, 1048 _PATH_HOST_RSA_KEY_FILE, "", NULL); 1049 sensitive_data.keys[4] = key_load_private_cert(KEY_ED25519, 1050 _PATH_HOST_ED25519_KEY_FILE, "", NULL); 1051 sensitive_data.keys[5] = key_load_private_type(KEY_DSA, 1052 _PATH_HOST_DSA_KEY_FILE, "", NULL, NULL); 1053 sensitive_data.keys[6] = key_load_private_type(KEY_ECDSA, 1054 _PATH_HOST_ECDSA_KEY_FILE, "", NULL, NULL); 1055 sensitive_data.keys[7] = key_load_private_type(KEY_RSA, 1056 _PATH_HOST_RSA_KEY_FILE, "", NULL, NULL); 1057 sensitive_data.keys[8] = key_load_private_type(KEY_ED25519, 1058 _PATH_HOST_ED25519_KEY_FILE, "", NULL, NULL); 1059 PRIV_END; 1060 1061 if (options.hostbased_authentication == 1 && 1062 sensitive_data.keys[0] == NULL && 1063 sensitive_data.keys[5] == NULL && 1064 sensitive_data.keys[6] == NULL && 1065 sensitive_data.keys[7] == NULL && 1066 sensitive_data.keys[8] == NULL) { 1067 sensitive_data.keys[1] = key_load_cert( 1068 _PATH_HOST_DSA_KEY_FILE); 1069 sensitive_data.keys[2] = key_load_cert( 1070 _PATH_HOST_ECDSA_KEY_FILE); 1071 sensitive_data.keys[3] = key_load_cert( 1072 _PATH_HOST_RSA_KEY_FILE); 1073 sensitive_data.keys[4] = key_load_cert( 1074 _PATH_HOST_ED25519_KEY_FILE); 1075 sensitive_data.keys[5] = key_load_public( 1076 _PATH_HOST_DSA_KEY_FILE, NULL); 1077 sensitive_data.keys[6] = key_load_public( 1078 _PATH_HOST_ECDSA_KEY_FILE, NULL); 1079 sensitive_data.keys[7] = key_load_public( 1080 _PATH_HOST_RSA_KEY_FILE, NULL); 1081 sensitive_data.keys[8] = key_load_public( 1082 _PATH_HOST_ED25519_KEY_FILE, NULL); 1083 sensitive_data.external_keysign = 1; 1084 } 1085 } 1086 /* 1087 * Get rid of any extra privileges that we may have. We will no 1088 * longer need them. Also, extra privileges could make it very hard 1089 * to read identity files and other non-world-readable files from the 1090 * user's home directory if it happens to be on a NFS volume where 1091 * root is mapped to nobody. 1092 */ 1093 if (original_effective_uid == 0) { 1094 PRIV_START; 1095 permanently_set_uid(pw); 1096 } 1097 1098 /* 1099 * Now that we are back to our own permissions, create ~/.ssh 1100 * directory if it doesn't already exist. 1101 */ 1102 if (config == NULL) { 1103 r = snprintf(buf, sizeof buf, "%s%s%s", pw->pw_dir, 1104 strcmp(pw->pw_dir, "/") ? "/" : "", _PATH_SSH_USER_DIR); 1105 if (r > 0 && (size_t)r < sizeof(buf) && stat(buf, &st) < 0) 1106 if (mkdir(buf, 0700) < 0) 1107 error("Could not create directory '%.200s'.", 1108 buf); 1109 } 1110 1111 /* load options.identity_files */ 1112 load_public_identity_files(); 1113 1114 /* Expand ~ in known host file names. */ 1115 tilde_expand_paths(options.system_hostfiles, 1116 options.num_system_hostfiles); 1117 tilde_expand_paths(options.user_hostfiles, options.num_user_hostfiles); 1118 1119 signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */ 1120 signal(SIGCHLD, main_sigchld_handler); 1121 1122 /* Log into the remote system. Never returns if the login fails. */ 1123 ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, 1124 options.port, pw, timeout_ms); 1125 1126 if (packet_connection_is_on_socket()) { 1127 verbose("Authenticated to %s ([%s]:%d).", host, 1128 get_remote_ipaddr(), get_remote_port()); 1129 } else { 1130 verbose("Authenticated to %s (via proxy).", host); 1131 } 1132 1133 /* We no longer need the private host keys. Clear them now. */ 1134 if (sensitive_data.nkeys != 0) { 1135 for (i = 0; i < sensitive_data.nkeys; i++) { 1136 if (sensitive_data.keys[i] != NULL) { 1137 /* Destroys contents safely */ 1138 debug3("clear hostkey %d", i); 1139 key_free(sensitive_data.keys[i]); 1140 sensitive_data.keys[i] = NULL; 1141 } 1142 } 1143 free(sensitive_data.keys); 1144 } 1145 for (i = 0; i < options.num_identity_files; i++) { 1146 free(options.identity_files[i]); 1147 options.identity_files[i] = NULL; 1148 if (options.identity_keys[i]) { 1149 key_free(options.identity_keys[i]); 1150 options.identity_keys[i] = NULL; 1151 } 1152 } 1153 1154 exit_status = compat20 ? ssh_session2() : ssh_session(); 1155 packet_close(); 1156 1157 if (options.control_path != NULL && muxserver_sock != -1) 1158 unlink(options.control_path); 1159 1160 /* Kill ProxyCommand if it is running. */ 1161 ssh_kill_proxy_command(); 1162 1163 return exit_status; 1164 } 1165 1166 static void 1167 control_persist_detach(void) 1168 { 1169 pid_t pid; 1170 int devnull; 1171 1172 debug("%s: backgrounding master process", __func__); 1173 1174 /* 1175 * master (current process) into the background, and make the 1176 * foreground process a client of the backgrounded master. 1177 */ 1178 switch ((pid = fork())) { 1179 case -1: 1180 fatal("%s: fork: %s", __func__, strerror(errno)); 1181 case 0: 1182 /* Child: master process continues mainloop */ 1183 break; 1184 default: 1185 /* Parent: set up mux slave to connect to backgrounded master */ 1186 debug2("%s: background process is %ld", __func__, (long)pid); 1187 stdin_null_flag = ostdin_null_flag; 1188 options.request_tty = orequest_tty; 1189 tty_flag = otty_flag; 1190 close(muxserver_sock); 1191 muxserver_sock = -1; 1192 options.control_master = SSHCTL_MASTER_NO; 1193 muxclient(options.control_path); 1194 /* muxclient() doesn't return on success. */ 1195 fatal("Failed to connect to new control master"); 1196 } 1197 if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) { 1198 error("%s: open(\"/dev/null\"): %s", __func__, 1199 strerror(errno)); 1200 } else { 1201 if (dup2(devnull, STDIN_FILENO) == -1 || 1202 dup2(devnull, STDOUT_FILENO) == -1) 1203 error("%s: dup2: %s", __func__, strerror(errno)); 1204 if (devnull > STDERR_FILENO) 1205 close(devnull); 1206 } 1207 daemon(1, 1); 1208 setproctitle("%s [mux]", options.control_path); 1209 } 1210 1211 /* Do fork() after authentication. Used by "ssh -f" */ 1212 static void 1213 fork_postauth(void) 1214 { 1215 if (need_controlpersist_detach) 1216 control_persist_detach(); 1217 debug("forking to background"); 1218 fork_after_authentication_flag = 0; 1219 if (daemon(1, 1) < 0) 1220 fatal("daemon() failed: %.200s", strerror(errno)); 1221 } 1222 1223 /* Callback for remote forward global requests */ 1224 static void 1225 ssh_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 1226 { 1227 Forward *rfwd = (Forward *)ctxt; 1228 1229 /* XXX verbose() on failure? */ 1230 debug("remote forward %s for: listen %d, connect %s:%d", 1231 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 1232 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 1233 if (rfwd->listen_port == 0) { 1234 if (type == SSH2_MSG_REQUEST_SUCCESS) { 1235 rfwd->allocated_port = packet_get_int(); 1236 logit("Allocated port %u for remote forward to %s:%d", 1237 rfwd->allocated_port, 1238 rfwd->connect_host, rfwd->connect_port); 1239 channel_update_permitted_opens(rfwd->handle, 1240 rfwd->allocated_port); 1241 } else { 1242 channel_update_permitted_opens(rfwd->handle, -1); 1243 } 1244 } 1245 1246 if (type == SSH2_MSG_REQUEST_FAILURE) { 1247 if (options.exit_on_forward_failure) 1248 fatal("Error: remote port forwarding failed for " 1249 "listen port %d", rfwd->listen_port); 1250 else 1251 logit("Warning: remote port forwarding failed for " 1252 "listen port %d", rfwd->listen_port); 1253 } 1254 if (++remote_forward_confirms_received == options.num_remote_forwards) { 1255 debug("All remote forwarding requests processed"); 1256 if (fork_after_authentication_flag) 1257 fork_postauth(); 1258 } 1259 } 1260 1261 static void 1262 client_cleanup_stdio_fwd(int id, void *arg) 1263 { 1264 debug("stdio forwarding: done"); 1265 cleanup_exit(0); 1266 } 1267 1268 static void 1269 ssh_init_stdio_forwarding(void) 1270 { 1271 Channel *c; 1272 int in, out; 1273 1274 if (stdio_forward_host == NULL) 1275 return; 1276 if (!compat20) 1277 fatal("stdio forwarding require Protocol 2"); 1278 1279 debug3("%s: %s:%d", __func__, stdio_forward_host, stdio_forward_port); 1280 1281 if ((in = dup(STDIN_FILENO)) < 0 || 1282 (out = dup(STDOUT_FILENO)) < 0) 1283 fatal("channel_connect_stdio_fwd: dup() in/out failed"); 1284 if ((c = channel_connect_stdio_fwd(stdio_forward_host, 1285 stdio_forward_port, in, out)) == NULL) 1286 fatal("%s: channel_connect_stdio_fwd failed", __func__); 1287 channel_register_cleanup(c->self, client_cleanup_stdio_fwd, 0); 1288 } 1289 1290 static void 1291 ssh_init_forwarding(void) 1292 { 1293 int success = 0; 1294 int i; 1295 1296 /* Initiate local TCP/IP port forwardings. */ 1297 for (i = 0; i < options.num_local_forwards; i++) { 1298 debug("Local connections to %.200s:%d forwarded to remote " 1299 "address %.200s:%d", 1300 (options.local_forwards[i].listen_host == NULL) ? 1301 (options.gateway_ports ? "*" : "LOCALHOST") : 1302 options.local_forwards[i].listen_host, 1303 options.local_forwards[i].listen_port, 1304 options.local_forwards[i].connect_host, 1305 options.local_forwards[i].connect_port); 1306 success += channel_setup_local_fwd_listener( 1307 options.local_forwards[i].listen_host, 1308 options.local_forwards[i].listen_port, 1309 options.local_forwards[i].connect_host, 1310 options.local_forwards[i].connect_port, 1311 options.gateway_ports); 1312 } 1313 if (i > 0 && success != i && options.exit_on_forward_failure) 1314 fatal("Could not request local forwarding."); 1315 if (i > 0 && success == 0) 1316 error("Could not request local forwarding."); 1317 1318 /* Initiate remote TCP/IP port forwardings. */ 1319 for (i = 0; i < options.num_remote_forwards; i++) { 1320 debug("Remote connections from %.200s:%d forwarded to " 1321 "local address %.200s:%d", 1322 (options.remote_forwards[i].listen_host == NULL) ? 1323 "LOCALHOST" : options.remote_forwards[i].listen_host, 1324 options.remote_forwards[i].listen_port, 1325 options.remote_forwards[i].connect_host, 1326 options.remote_forwards[i].connect_port); 1327 options.remote_forwards[i].handle = 1328 channel_request_remote_forwarding( 1329 options.remote_forwards[i].listen_host, 1330 options.remote_forwards[i].listen_port, 1331 options.remote_forwards[i].connect_host, 1332 options.remote_forwards[i].connect_port); 1333 if (options.remote_forwards[i].handle < 0) { 1334 if (options.exit_on_forward_failure) 1335 fatal("Could not request remote forwarding."); 1336 else 1337 logit("Warning: Could not request remote " 1338 "forwarding."); 1339 } else { 1340 client_register_global_confirm(ssh_confirm_remote_forward, 1341 &options.remote_forwards[i]); 1342 } 1343 } 1344 1345 /* Initiate tunnel forwarding. */ 1346 if (options.tun_open != SSH_TUNMODE_NO) { 1347 if (client_request_tun_fwd(options.tun_open, 1348 options.tun_local, options.tun_remote) == -1) { 1349 if (options.exit_on_forward_failure) 1350 fatal("Could not request tunnel forwarding."); 1351 else 1352 error("Could not request tunnel forwarding."); 1353 } 1354 } 1355 } 1356 1357 static void 1358 check_agent_present(void) 1359 { 1360 if (options.forward_agent) { 1361 /* Clear agent forwarding if we don't have an agent. */ 1362 if (!ssh_agent_present()) 1363 options.forward_agent = 0; 1364 } 1365 } 1366 1367 static int 1368 ssh_session(void) 1369 { 1370 int type; 1371 int interactive = 0; 1372 int have_tty = 0; 1373 struct winsize ws; 1374 char *cp; 1375 const char *display; 1376 1377 /* Enable compression if requested. */ 1378 if (options.compression) { 1379 debug("Requesting compression at level %d.", 1380 options.compression_level); 1381 1382 if (options.compression_level < 1 || 1383 options.compression_level > 9) 1384 fatal("Compression level must be from 1 (fast) to " 1385 "9 (slow, best)."); 1386 1387 /* Send the request. */ 1388 packet_start(SSH_CMSG_REQUEST_COMPRESSION); 1389 packet_put_int(options.compression_level); 1390 packet_send(); 1391 packet_write_wait(); 1392 type = packet_read(); 1393 if (type == SSH_SMSG_SUCCESS) 1394 packet_start_compression(options.compression_level); 1395 else if (type == SSH_SMSG_FAILURE) 1396 logit("Warning: Remote host refused compression."); 1397 else 1398 packet_disconnect("Protocol error waiting for " 1399 "compression response."); 1400 } 1401 /* Allocate a pseudo tty if appropriate. */ 1402 if (tty_flag) { 1403 debug("Requesting pty."); 1404 1405 /* Start the packet. */ 1406 packet_start(SSH_CMSG_REQUEST_PTY); 1407 1408 /* Store TERM in the packet. There is no limit on the 1409 length of the string. */ 1410 cp = getenv("TERM"); 1411 if (!cp) 1412 cp = ""; 1413 packet_put_cstring(cp); 1414 1415 /* Store window size in the packet. */ 1416 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 1417 memset(&ws, 0, sizeof(ws)); 1418 packet_put_int((u_int)ws.ws_row); 1419 packet_put_int((u_int)ws.ws_col); 1420 packet_put_int((u_int)ws.ws_xpixel); 1421 packet_put_int((u_int)ws.ws_ypixel); 1422 1423 /* Store tty modes in the packet. */ 1424 tty_make_modes(fileno(stdin), NULL); 1425 1426 /* Send the packet, and wait for it to leave. */ 1427 packet_send(); 1428 packet_write_wait(); 1429 1430 /* Read response from the server. */ 1431 type = packet_read(); 1432 if (type == SSH_SMSG_SUCCESS) { 1433 interactive = 1; 1434 have_tty = 1; 1435 } else if (type == SSH_SMSG_FAILURE) 1436 logit("Warning: Remote host failed or refused to " 1437 "allocate a pseudo tty."); 1438 else 1439 packet_disconnect("Protocol error waiting for pty " 1440 "request response."); 1441 } 1442 /* Request X11 forwarding if enabled and DISPLAY is set. */ 1443 display = getenv("DISPLAY"); 1444 if (options.forward_x11 && display != NULL) { 1445 char *proto, *data; 1446 /* Get reasonable local authentication information. */ 1447 client_x11_get_proto(display, options.xauth_location, 1448 options.forward_x11_trusted, 1449 options.forward_x11_timeout, 1450 &proto, &data); 1451 /* Request forwarding with authentication spoofing. */ 1452 debug("Requesting X11 forwarding with authentication " 1453 "spoofing."); 1454 x11_request_forwarding_with_spoofing(0, display, proto, 1455 data, 0); 1456 /* Read response from the server. */ 1457 type = packet_read(); 1458 if (type == SSH_SMSG_SUCCESS) { 1459 interactive = 1; 1460 } else if (type == SSH_SMSG_FAILURE) { 1461 logit("Warning: Remote host denied X11 forwarding."); 1462 } else { 1463 packet_disconnect("Protocol error waiting for X11 " 1464 "forwarding"); 1465 } 1466 } 1467 /* Tell the packet module whether this is an interactive session. */ 1468 packet_set_interactive(interactive, 1469 options.ip_qos_interactive, options.ip_qos_bulk); 1470 1471 /* Request authentication agent forwarding if appropriate. */ 1472 check_agent_present(); 1473 1474 if (options.forward_agent) { 1475 debug("Requesting authentication agent forwarding."); 1476 auth_request_forwarding(); 1477 1478 /* Read response from the server. */ 1479 type = packet_read(); 1480 packet_check_eom(); 1481 if (type != SSH_SMSG_SUCCESS) 1482 logit("Warning: Remote host denied authentication agent forwarding."); 1483 } 1484 1485 /* Initiate port forwardings. */ 1486 ssh_init_stdio_forwarding(); 1487 ssh_init_forwarding(); 1488 1489 /* Execute a local command */ 1490 if (options.local_command != NULL && 1491 options.permit_local_command) 1492 ssh_local_cmd(options.local_command); 1493 1494 /* 1495 * If requested and we are not interested in replies to remote 1496 * forwarding requests, then let ssh continue in the background. 1497 */ 1498 if (fork_after_authentication_flag) { 1499 if (options.exit_on_forward_failure && 1500 options.num_remote_forwards > 0) { 1501 debug("deferring postauth fork until remote forward " 1502 "confirmation received"); 1503 } else 1504 fork_postauth(); 1505 } 1506 1507 /* 1508 * If a command was specified on the command line, execute the 1509 * command now. Otherwise request the server to start a shell. 1510 */ 1511 if (buffer_len(&command) > 0) { 1512 int len = buffer_len(&command); 1513 if (len > 900) 1514 len = 900; 1515 debug("Sending command: %.*s", len, 1516 (u_char *)buffer_ptr(&command)); 1517 packet_start(SSH_CMSG_EXEC_CMD); 1518 packet_put_string(buffer_ptr(&command), buffer_len(&command)); 1519 packet_send(); 1520 packet_write_wait(); 1521 } else { 1522 debug("Requesting shell."); 1523 packet_start(SSH_CMSG_EXEC_SHELL); 1524 packet_send(); 1525 packet_write_wait(); 1526 } 1527 1528 /* Enter the interactive session. */ 1529 return client_loop(have_tty, tty_flag ? 1530 options.escape_char : SSH_ESCAPECHAR_NONE, 0); 1531 } 1532 1533 /* request pty/x11/agent/tcpfwd/shell for channel */ 1534 static void 1535 ssh_session2_setup(int id, int success, void *arg) 1536 { 1537 extern char **environ; 1538 const char *display; 1539 int interactive = tty_flag; 1540 1541 if (!success) 1542 return; /* No need for error message, channels code sens one */ 1543 1544 display = getenv("DISPLAY"); 1545 if (options.forward_x11 && display != NULL) { 1546 char *proto, *data; 1547 /* Get reasonable local authentication information. */ 1548 client_x11_get_proto(display, options.xauth_location, 1549 options.forward_x11_trusted, 1550 options.forward_x11_timeout, &proto, &data); 1551 /* Request forwarding with authentication spoofing. */ 1552 debug("Requesting X11 forwarding with authentication " 1553 "spoofing."); 1554 x11_request_forwarding_with_spoofing(id, display, proto, 1555 data, 1); 1556 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); 1557 /* XXX exit_on_forward_failure */ 1558 interactive = 1; 1559 } 1560 1561 check_agent_present(); 1562 if (options.forward_agent) { 1563 debug("Requesting authentication agent forwarding."); 1564 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1565 packet_send(); 1566 } 1567 1568 /* Tell the packet module whether this is an interactive session. */ 1569 packet_set_interactive(interactive, 1570 options.ip_qos_interactive, options.ip_qos_bulk); 1571 1572 client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), 1573 NULL, fileno(stdin), &command, environ); 1574 } 1575 1576 /* open new channel for a session */ 1577 static int 1578 ssh_session2_open(void) 1579 { 1580 Channel *c; 1581 int window, packetmax, in, out, err; 1582 1583 if (stdin_null_flag) { 1584 in = open(_PATH_DEVNULL, O_RDONLY); 1585 } else { 1586 in = dup(STDIN_FILENO); 1587 } 1588 out = dup(STDOUT_FILENO); 1589 err = dup(STDERR_FILENO); 1590 1591 if (in < 0 || out < 0 || err < 0) 1592 fatal("dup() in/out/err failed"); 1593 1594 /* enable nonblocking unless tty */ 1595 if (!isatty(in)) 1596 set_nonblock(in); 1597 if (!isatty(out)) 1598 set_nonblock(out); 1599 if (!isatty(err)) 1600 set_nonblock(err); 1601 1602 window = CHAN_SES_WINDOW_DEFAULT; 1603 packetmax = CHAN_SES_PACKET_DEFAULT; 1604 if (tty_flag) { 1605 window >>= 1; 1606 packetmax >>= 1; 1607 } 1608 c = channel_new( 1609 "session", SSH_CHANNEL_OPENING, in, out, err, 1610 window, packetmax, CHAN_EXTENDED_WRITE, 1611 "client-session", /*nonblock*/0); 1612 1613 debug3("ssh_session2_open: channel_new: %d", c->self); 1614 1615 channel_send_open(c->self); 1616 if (!no_shell_flag) 1617 channel_register_open_confirm(c->self, 1618 ssh_session2_setup, NULL); 1619 1620 return c->self; 1621 } 1622 1623 static int 1624 ssh_session2(void) 1625 { 1626 int id = -1; 1627 1628 /* XXX should be pre-session */ 1629 if (!options.control_persist) 1630 ssh_init_stdio_forwarding(); 1631 ssh_init_forwarding(); 1632 1633 /* Start listening for multiplex clients */ 1634 muxserver_listen(); 1635 1636 /* 1637 * If we are in control persist mode and have a working mux listen 1638 * socket, then prepare to background ourselves and have a foreground 1639 * client attach as a control slave. 1640 * NB. we must save copies of the flags that we override for 1641 * the backgrounding, since we defer attachment of the slave until 1642 * after the connection is fully established (in particular, 1643 * async rfwd replies have been received for ExitOnForwardFailure). 1644 */ 1645 if (options.control_persist && muxserver_sock != -1) { 1646 ostdin_null_flag = stdin_null_flag; 1647 ono_shell_flag = no_shell_flag; 1648 orequest_tty = options.request_tty; 1649 otty_flag = tty_flag; 1650 stdin_null_flag = 1; 1651 no_shell_flag = 1; 1652 tty_flag = 0; 1653 if (!fork_after_authentication_flag) 1654 need_controlpersist_detach = 1; 1655 fork_after_authentication_flag = 1; 1656 } 1657 /* 1658 * ControlPersist mux listen socket setup failed, attempt the 1659 * stdio forward setup that we skipped earlier. 1660 */ 1661 if (options.control_persist && muxserver_sock == -1) 1662 ssh_init_stdio_forwarding(); 1663 1664 if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) 1665 id = ssh_session2_open(); 1666 else { 1667 packet_set_interactive( 1668 options.control_master == SSHCTL_MASTER_NO, 1669 options.ip_qos_interactive, options.ip_qos_bulk); 1670 } 1671 1672 /* If we don't expect to open a new session, then disallow it */ 1673 if (options.control_master == SSHCTL_MASTER_NO && 1674 (datafellows & SSH_NEW_OPENSSH)) { 1675 debug("Requesting no-more-sessions@openssh.com"); 1676 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1677 packet_put_cstring("no-more-sessions@openssh.com"); 1678 packet_put_char(0); 1679 packet_send(); 1680 } 1681 1682 /* Execute a local command */ 1683 if (options.local_command != NULL && 1684 options.permit_local_command) 1685 ssh_local_cmd(options.local_command); 1686 1687 /* 1688 * If requested and we are not interested in replies to remote 1689 * forwarding requests, then let ssh continue in the background. 1690 */ 1691 if (fork_after_authentication_flag) { 1692 if (options.exit_on_forward_failure && 1693 options.num_remote_forwards > 0) { 1694 debug("deferring postauth fork until remote forward " 1695 "confirmation received"); 1696 } else 1697 fork_postauth(); 1698 } 1699 1700 if (options.use_roaming) 1701 request_roaming(); 1702 1703 return client_loop(tty_flag, tty_flag ? 1704 options.escape_char : SSH_ESCAPECHAR_NONE, id); 1705 } 1706 1707 static void 1708 load_public_identity_files(void) 1709 { 1710 char *filename, *cp, thishost[NI_MAXHOST]; 1711 char *pwdir = NULL, *pwname = NULL; 1712 int i = 0; 1713 Key *public; 1714 struct passwd *pw; 1715 u_int n_ids; 1716 char *identity_files[SSH_MAX_IDENTITY_FILES]; 1717 Key *identity_keys[SSH_MAX_IDENTITY_FILES]; 1718 #ifdef ENABLE_PKCS11 1719 Key **keys; 1720 int nkeys; 1721 #endif /* PKCS11 */ 1722 1723 n_ids = 0; 1724 memset(identity_files, 0, sizeof(identity_files)); 1725 memset(identity_keys, 0, sizeof(identity_keys)); 1726 1727 #ifdef ENABLE_PKCS11 1728 if (options.pkcs11_provider != NULL && 1729 options.num_identity_files < SSH_MAX_IDENTITY_FILES && 1730 (pkcs11_init(!options.batch_mode) == 0) && 1731 (nkeys = pkcs11_add_provider(options.pkcs11_provider, NULL, 1732 &keys)) > 0) { 1733 for (i = 0; i < nkeys; i++) { 1734 if (n_ids >= SSH_MAX_IDENTITY_FILES) { 1735 key_free(keys[i]); 1736 continue; 1737 } 1738 identity_keys[n_ids] = keys[i]; 1739 identity_files[n_ids] = 1740 xstrdup(options.pkcs11_provider); /* XXX */ 1741 n_ids++; 1742 } 1743 free(keys); 1744 } 1745 #endif /* ENABLE_PKCS11 */ 1746 if ((pw = getpwuid(original_real_uid)) == NULL) 1747 fatal("load_public_identity_files: getpwuid failed"); 1748 pwname = xstrdup(pw->pw_name); 1749 pwdir = xstrdup(pw->pw_dir); 1750 if (gethostname(thishost, sizeof(thishost)) == -1) 1751 fatal("load_public_identity_files: gethostname: %s", 1752 strerror(errno)); 1753 for (i = 0; i < options.num_identity_files; i++) { 1754 if (n_ids >= SSH_MAX_IDENTITY_FILES || 1755 strcasecmp(options.identity_files[i], "none") == 0) { 1756 free(options.identity_files[i]); 1757 continue; 1758 } 1759 cp = tilde_expand_filename(options.identity_files[i], 1760 original_real_uid); 1761 filename = percent_expand(cp, "d", pwdir, 1762 "u", pwname, "l", thishost, "h", host, 1763 "r", options.user, (char *)NULL); 1764 free(cp); 1765 public = key_load_public(filename, NULL); 1766 debug("identity file %s type %d", filename, 1767 public ? public->type : -1); 1768 free(options.identity_files[i]); 1769 identity_files[n_ids] = filename; 1770 identity_keys[n_ids] = public; 1771 1772 if (++n_ids >= SSH_MAX_IDENTITY_FILES) 1773 continue; 1774 1775 /* Try to add the certificate variant too */ 1776 xasprintf(&cp, "%s-cert", filename); 1777 public = key_load_public(cp, NULL); 1778 debug("identity file %s type %d", cp, 1779 public ? public->type : -1); 1780 if (public == NULL) { 1781 free(cp); 1782 continue; 1783 } 1784 if (!key_is_cert(public)) { 1785 debug("%s: key %s type %s is not a certificate", 1786 __func__, cp, key_type(public)); 1787 key_free(public); 1788 free(cp); 1789 continue; 1790 } 1791 identity_keys[n_ids] = public; 1792 /* point to the original path, most likely the private key */ 1793 identity_files[n_ids] = xstrdup(filename); 1794 n_ids++; 1795 } 1796 options.num_identity_files = n_ids; 1797 memcpy(options.identity_files, identity_files, sizeof(identity_files)); 1798 memcpy(options.identity_keys, identity_keys, sizeof(identity_keys)); 1799 1800 explicit_bzero(pwname, strlen(pwname)); 1801 free(pwname); 1802 explicit_bzero(pwdir, strlen(pwdir)); 1803 free(pwdir); 1804 } 1805 1806 static void 1807 main_sigchld_handler(int sig) 1808 { 1809 int save_errno = errno; 1810 pid_t pid; 1811 int status; 1812 1813 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 1814 (pid < 0 && errno == EINTR)) 1815 ; 1816 1817 signal(sig, main_sigchld_handler); 1818 errno = save_errno; 1819 } 1820