1 /* $OpenBSD: sshd.c,v 1.534 2019/04/18 18:56:16 dtucker 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 * This program is the ssh daemon. It listens for connections from clients, 7 * and performs authentication, executes use commands or shell, and forwards 8 * information to/from the application to the user client over an encrypted 9 * connection. This can also handle forwarding of X11, TCP/IP, and 10 * authentication agent connections. 11 * 12 * As far as I am concerned, the code I have written for this software 13 * can be used freely for any purpose. Any derived versions of this 14 * software must be clearly marked as such, and if the derived work is 15 * incompatible with the protocol description in the RFC file, it must be 16 * called by a name other than "ssh" or "Secure Shell". 17 * 18 * SSH2 implementation: 19 * Privilege Separation: 20 * 21 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. 22 * Copyright (c) 2002 Niels Provos. All rights reserved. 23 * 24 * Redistribution and use in source and binary forms, with or without 25 * modification, are permitted provided that the following conditions 26 * are met: 27 * 1. Redistributions of source code must retain the above copyright 28 * notice, this list of conditions and the following disclaimer. 29 * 2. Redistributions in binary form must reproduce the above copyright 30 * notice, this list of conditions and the following disclaimer in the 31 * documentation and/or other materials provided with the distribution. 32 * 33 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 34 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 36 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 37 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 39 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 40 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 42 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 43 */ 44 45 #include <sys/types.h> 46 #include <sys/ioctl.h> 47 #include <sys/wait.h> 48 #include <sys/tree.h> 49 #include <sys/stat.h> 50 #include <sys/socket.h> 51 #include <sys/time.h> 52 #include <sys/queue.h> 53 54 #include <errno.h> 55 #include <fcntl.h> 56 #include <netdb.h> 57 #include <paths.h> 58 #include <pwd.h> 59 #include <signal.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <unistd.h> 64 #include <limits.h> 65 66 #ifdef WITH_OPENSSL 67 #include <openssl/bn.h> 68 #endif 69 70 #include "xmalloc.h" 71 #include "ssh.h" 72 #include "ssh2.h" 73 #include "sshpty.h" 74 #include "packet.h" 75 #include "log.h" 76 #include "sshbuf.h" 77 #include "misc.h" 78 #include "match.h" 79 #include "servconf.h" 80 #include "uidswap.h" 81 #include "compat.h" 82 #include "cipher.h" 83 #include "digest.h" 84 #include "sshkey.h" 85 #include "kex.h" 86 #include "myproposal.h" 87 #include "authfile.h" 88 #include "pathnames.h" 89 #include "atomicio.h" 90 #include "canohost.h" 91 #include "hostfile.h" 92 #include "auth.h" 93 #include "authfd.h" 94 #include "msg.h" 95 #include "dispatch.h" 96 #include "channels.h" 97 #include "session.h" 98 #include "monitor.h" 99 #ifdef GSSAPI 100 #include "ssh-gss.h" 101 #endif 102 #include "monitor_wrap.h" 103 #include "ssh-sandbox.h" 104 #include "auth-options.h" 105 #include "version.h" 106 #include "ssherr.h" 107 108 /* Re-exec fds */ 109 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) 110 #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) 111 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) 112 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) 113 114 extern char *__progname; 115 116 /* Server configuration options. */ 117 ServerOptions options; 118 119 /* Name of the server configuration file. */ 120 char *config_file_name = _PATH_SERVER_CONFIG_FILE; 121 122 /* 123 * Debug mode flag. This can be set on the command line. If debug 124 * mode is enabled, extra debugging output will be sent to the system 125 * log, the daemon will not go to background, and will exit after processing 126 * the first connection. 127 */ 128 int debug_flag = 0; 129 130 /* 131 * Indicating that the daemon should only test the configuration and keys. 132 * If test_flag > 1 ("-T" flag), then sshd will also dump the effective 133 * configuration, optionally using connection information provided by the 134 * "-C" flag. 135 */ 136 static int test_flag = 0; 137 138 /* Flag indicating that the daemon is being started from inetd. */ 139 static int inetd_flag = 0; 140 141 /* Flag indicating that sshd should not detach and become a daemon. */ 142 static int no_daemon_flag = 0; 143 144 /* debug goes to stderr unless inetd_flag is set */ 145 static int log_stderr = 0; 146 147 /* Saved arguments to main(). */ 148 static char **saved_argv; 149 150 /* re-exec */ 151 static int rexeced_flag = 0; 152 static int rexec_flag = 1; 153 static int rexec_argc = 0; 154 static char **rexec_argv; 155 156 /* 157 * The sockets that the server is listening; this is used in the SIGHUP 158 * signal handler. 159 */ 160 #define MAX_LISTEN_SOCKS 16 161 static int listen_socks[MAX_LISTEN_SOCKS]; 162 static int num_listen_socks = 0; 163 164 /* Daemon's agent connection */ 165 int auth_sock = -1; 166 static int have_agent = 0; 167 168 /* 169 * Any really sensitive data in the application is contained in this 170 * structure. The idea is that this structure could be locked into memory so 171 * that the pages do not get written into swap. However, there are some 172 * problems. The private key contains BIGNUMs, and we do not (in principle) 173 * have access to the internals of them, and locking just the structure is 174 * not very useful. Currently, memory locking is not implemented. 175 */ 176 struct { 177 struct sshkey **host_keys; /* all private host keys */ 178 struct sshkey **host_pubkeys; /* all public host keys */ 179 struct sshkey **host_certificates; /* all public host certificates */ 180 int have_ssh2_key; 181 } sensitive_data; 182 183 /* This is set to true when a signal is received. */ 184 static volatile sig_atomic_t received_sighup = 0; 185 static volatile sig_atomic_t received_sigterm = 0; 186 187 /* session identifier, used by RSA-auth */ 188 u_char session_id[16]; 189 190 /* same for ssh2 */ 191 u_char *session_id2 = NULL; 192 u_int session_id2_len = 0; 193 194 /* record remote hostname or ip */ 195 u_int utmp_len = HOST_NAME_MAX+1; 196 197 /* 198 * startup_pipes/flags are used for tracking children of the listening sshd 199 * process early in their lifespans. This tracking is needed for three things: 200 * 201 * 1) Implementing the MaxStartups limit of concurrent unauthenticated 202 * connections. 203 * 2) Avoiding a race condition for SIGHUP processing, where child processes 204 * may have listen_socks open that could collide with main listener process 205 * after it restarts. 206 * 3) Ensuring that rexec'd sshd processes have received their initial state 207 * from the parent listen process before handling SIGHUP. 208 * 209 * Child processes signal that they have completed closure of the listen_socks 210 * and (if applicable) received their rexec state by sending a char over their 211 * sock. Child processes signal that authentication has completed by closing 212 * the sock (or by exiting). 213 */ 214 static int *startup_pipes = NULL; 215 static int *startup_flags = NULL; /* Indicates child closed listener */ 216 static int startup_pipe = -1; /* in child */ 217 218 /* variables used for privilege separation */ 219 int use_privsep = -1; 220 struct monitor *pmonitor = NULL; 221 int privsep_is_preauth = 1; 222 223 /* global connection state and authentication contexts */ 224 Authctxt *the_authctxt = NULL; 225 struct ssh *the_active_state; 226 227 /* global key/cert auth options. XXX move to permanent ssh->authctxt? */ 228 struct sshauthopt *auth_opts = NULL; 229 230 /* sshd_config buffer */ 231 struct sshbuf *cfg; 232 233 /* message to be displayed after login */ 234 struct sshbuf *loginmsg; 235 236 /* Prototypes for various functions defined later in this file. */ 237 void destroy_sensitive_data(void); 238 void demote_sensitive_data(void); 239 static void do_ssh2_kex(struct ssh *); 240 241 /* 242 * Close all listening sockets 243 */ 244 static void 245 close_listen_socks(void) 246 { 247 int i; 248 249 for (i = 0; i < num_listen_socks; i++) 250 close(listen_socks[i]); 251 num_listen_socks = -1; 252 } 253 254 static void 255 close_startup_pipes(void) 256 { 257 int i; 258 259 if (startup_pipes) 260 for (i = 0; i < options.max_startups; i++) 261 if (startup_pipes[i] != -1) 262 close(startup_pipes[i]); 263 } 264 265 /* 266 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; 267 * the effect is to reread the configuration file (and to regenerate 268 * the server key). 269 */ 270 271 /*ARGSUSED*/ 272 static void 273 sighup_handler(int sig) 274 { 275 int save_errno = errno; 276 277 received_sighup = 1; 278 errno = save_errno; 279 } 280 281 /* 282 * Called from the main program after receiving SIGHUP. 283 * Restarts the server. 284 */ 285 static void 286 sighup_restart(void) 287 { 288 logit("Received SIGHUP; restarting."); 289 if (options.pid_file != NULL) 290 unlink(options.pid_file); 291 close_listen_socks(); 292 close_startup_pipes(); 293 alarm(0); /* alarm timer persists across exec */ 294 signal(SIGHUP, SIG_IGN); /* will be restored after exec */ 295 execv(saved_argv[0], saved_argv); 296 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], 297 strerror(errno)); 298 exit(1); 299 } 300 301 /* 302 * Generic signal handler for terminating signals in the master daemon. 303 */ 304 /*ARGSUSED*/ 305 static void 306 sigterm_handler(int sig) 307 { 308 received_sigterm = sig; 309 } 310 311 /* 312 * SIGCHLD handler. This is called whenever a child dies. This will then 313 * reap any zombies left by exited children. 314 */ 315 /*ARGSUSED*/ 316 static void 317 main_sigchld_handler(int sig) 318 { 319 int save_errno = errno; 320 pid_t pid; 321 int status; 322 323 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 324 (pid < 0 && errno == EINTR)) 325 ; 326 errno = save_errno; 327 } 328 329 /* 330 * Signal handler for the alarm after the login grace period has expired. 331 */ 332 /*ARGSUSED*/ 333 static void 334 grace_alarm_handler(int sig) 335 { 336 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) 337 kill(pmonitor->m_pid, SIGALRM); 338 339 /* 340 * Try to kill any processes that we have spawned, E.g. authorized 341 * keys command helpers. 342 */ 343 if (getpgid(0) == getpid()) { 344 signal(SIGTERM, SIG_IGN); 345 kill(0, SIGTERM); 346 } 347 348 /* XXX pre-format ipaddr/port so we don't need to access active_state */ 349 /* Log error and exit. */ 350 sigdie("Timeout before authentication for %s port %d", 351 ssh_remote_ipaddr(the_active_state), 352 ssh_remote_port(the_active_state)); 353 } 354 355 /* Destroy the host and server keys. They will no longer be needed. */ 356 void 357 destroy_sensitive_data(void) 358 { 359 u_int i; 360 361 for (i = 0; i < options.num_host_key_files; i++) { 362 if (sensitive_data.host_keys[i]) { 363 sshkey_free(sensitive_data.host_keys[i]); 364 sensitive_data.host_keys[i] = NULL; 365 } 366 if (sensitive_data.host_certificates[i]) { 367 sshkey_free(sensitive_data.host_certificates[i]); 368 sensitive_data.host_certificates[i] = NULL; 369 } 370 } 371 } 372 373 /* Demote private to public keys for network child */ 374 void 375 demote_sensitive_data(void) 376 { 377 struct sshkey *tmp; 378 u_int i; 379 int r; 380 381 for (i = 0; i < options.num_host_key_files; i++) { 382 if (sensitive_data.host_keys[i]) { 383 if ((r = sshkey_from_private( 384 sensitive_data.host_keys[i], &tmp)) != 0) 385 fatal("could not demote host %s key: %s", 386 sshkey_type(sensitive_data.host_keys[i]), 387 ssh_err(r)); 388 sshkey_free(sensitive_data.host_keys[i]); 389 sensitive_data.host_keys[i] = tmp; 390 } 391 /* Certs do not need demotion */ 392 } 393 } 394 395 static void 396 privsep_preauth_child(void) 397 { 398 gid_t gidset[1]; 399 struct passwd *pw; 400 401 /* Enable challenge-response authentication for privilege separation */ 402 privsep_challenge_enable(); 403 404 #ifdef GSSAPI 405 /* Cache supported mechanism OIDs for later use */ 406 ssh_gssapi_prepare_supported_oids(); 407 #endif 408 409 /* Demote the private keys to public keys. */ 410 demote_sensitive_data(); 411 412 /* Demote the child */ 413 if (getuid() == 0 || geteuid() == 0) { 414 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) 415 fatal("Privilege separation user %s does not exist", 416 SSH_PRIVSEP_USER); 417 pw = pwcopy(pw); /* Ensure mutable */ 418 endpwent(); 419 freezero(pw->pw_passwd, strlen(pw->pw_passwd)); 420 421 /* Change our root directory */ 422 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) 423 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, 424 strerror(errno)); 425 if (chdir("/") == -1) 426 fatal("chdir(\"/\"): %s", strerror(errno)); 427 428 /* 429 * Drop our privileges 430 * NB. Can't use setusercontext() after chroot. 431 */ 432 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, 433 (u_int)pw->pw_gid); 434 gidset[0] = pw->pw_gid; 435 if (setgroups(1, gidset) < 0) 436 fatal("setgroups: %.100s", strerror(errno)); 437 permanently_set_uid(pw); 438 } 439 } 440 441 static int 442 privsep_preauth(struct ssh *ssh) 443 { 444 int status, r; 445 pid_t pid; 446 struct ssh_sandbox *box = NULL; 447 448 /* Set up unprivileged child process to deal with network data */ 449 pmonitor = monitor_init(); 450 /* Store a pointer to the kex for later rekeying */ 451 pmonitor->m_pkex = &ssh->kex; 452 453 if (use_privsep == PRIVSEP_ON) 454 box = ssh_sandbox_init(); 455 pid = fork(); 456 if (pid == -1) { 457 fatal("fork of unprivileged child failed"); 458 } else if (pid != 0) { 459 debug2("Network child is on pid %ld", (long)pid); 460 461 pmonitor->m_pid = pid; 462 if (have_agent) { 463 r = ssh_get_authentication_socket(&auth_sock); 464 if (r != 0) { 465 error("Could not get agent socket: %s", 466 ssh_err(r)); 467 have_agent = 0; 468 } 469 } 470 if (box != NULL) 471 ssh_sandbox_parent_preauth(box, pid); 472 monitor_child_preauth(ssh, pmonitor); 473 474 /* Wait for the child's exit status */ 475 while (waitpid(pid, &status, 0) < 0) { 476 if (errno == EINTR) 477 continue; 478 pmonitor->m_pid = -1; 479 fatal("%s: waitpid: %s", __func__, strerror(errno)); 480 } 481 privsep_is_preauth = 0; 482 pmonitor->m_pid = -1; 483 if (WIFEXITED(status)) { 484 if (WEXITSTATUS(status) != 0) 485 fatal("%s: preauth child exited with status %d", 486 __func__, WEXITSTATUS(status)); 487 } else if (WIFSIGNALED(status)) 488 fatal("%s: preauth child terminated by signal %d", 489 __func__, WTERMSIG(status)); 490 if (box != NULL) 491 ssh_sandbox_parent_finish(box); 492 return 1; 493 } else { 494 /* child */ 495 close(pmonitor->m_sendfd); 496 close(pmonitor->m_log_recvfd); 497 498 /* Arrange for logging to be sent to the monitor */ 499 set_log_handler(mm_log_handler, pmonitor); 500 501 privsep_preauth_child(); 502 setproctitle("%s", "[net]"); 503 if (box != NULL) 504 ssh_sandbox_child(box); 505 506 return 0; 507 } 508 } 509 510 static void 511 privsep_postauth(struct ssh *ssh, Authctxt *authctxt) 512 { 513 if (authctxt->pw->pw_uid == 0) { 514 /* File descriptor passing is broken or root login */ 515 use_privsep = 0; 516 goto skip; 517 } 518 519 /* New socket pair */ 520 monitor_reinit(pmonitor); 521 522 pmonitor->m_pid = fork(); 523 if (pmonitor->m_pid == -1) 524 fatal("fork of unprivileged child failed"); 525 else if (pmonitor->m_pid != 0) { 526 verbose("User child is on pid %ld", (long)pmonitor->m_pid); 527 sshbuf_reset(loginmsg); 528 monitor_clear_keystate(ssh, pmonitor); 529 monitor_child_postauth(ssh, pmonitor); 530 531 /* NEVERREACHED */ 532 exit(0); 533 } 534 535 /* child */ 536 537 close(pmonitor->m_sendfd); 538 pmonitor->m_sendfd = -1; 539 540 /* Demote the private keys to public keys. */ 541 demote_sensitive_data(); 542 543 /* Drop privileges */ 544 do_setusercontext(authctxt->pw); 545 546 skip: 547 /* It is safe now to apply the key state */ 548 monitor_apply_keystate(ssh, pmonitor); 549 550 /* 551 * Tell the packet layer that authentication was successful, since 552 * this information is not part of the key state. 553 */ 554 ssh_packet_set_authenticated(ssh); 555 } 556 557 static void 558 append_hostkey_type(struct sshbuf *b, const char *s) 559 { 560 int r; 561 562 if (match_pattern_list(s, options.hostkeyalgorithms, 0) != 1) { 563 debug3("%s: %s key not permitted by HostkeyAlgorithms", 564 __func__, s); 565 return; 566 } 567 if ((r = sshbuf_putf(b, "%s%s", sshbuf_len(b) > 0 ? "," : "", s)) != 0) 568 fatal("%s: sshbuf_putf: %s", __func__, ssh_err(r)); 569 } 570 571 static char * 572 list_hostkey_types(void) 573 { 574 struct sshbuf *b; 575 struct sshkey *key; 576 char *ret; 577 u_int i; 578 579 if ((b = sshbuf_new()) == NULL) 580 fatal("%s: sshbuf_new failed", __func__); 581 for (i = 0; i < options.num_host_key_files; i++) { 582 key = sensitive_data.host_keys[i]; 583 if (key == NULL) 584 key = sensitive_data.host_pubkeys[i]; 585 if (key == NULL) 586 continue; 587 switch (key->type) { 588 case KEY_RSA: 589 /* for RSA we also support SHA2 signatures */ 590 append_hostkey_type(b, "rsa-sha2-512"); 591 append_hostkey_type(b, "rsa-sha2-256"); 592 /* FALLTHROUGH */ 593 case KEY_DSA: 594 case KEY_ECDSA: 595 case KEY_ED25519: 596 case KEY_XMSS: 597 append_hostkey_type(b, sshkey_ssh_name(key)); 598 break; 599 } 600 /* If the private key has a cert peer, then list that too */ 601 key = sensitive_data.host_certificates[i]; 602 if (key == NULL) 603 continue; 604 switch (key->type) { 605 case KEY_RSA_CERT: 606 /* for RSA we also support SHA2 signatures */ 607 append_hostkey_type(b, 608 "rsa-sha2-512-cert-v01@openssh.com"); 609 append_hostkey_type(b, 610 "rsa-sha2-256-cert-v01@openssh.com"); 611 /* FALLTHROUGH */ 612 case KEY_DSA_CERT: 613 case KEY_ECDSA_CERT: 614 case KEY_ED25519_CERT: 615 case KEY_XMSS_CERT: 616 append_hostkey_type(b, sshkey_ssh_name(key)); 617 break; 618 } 619 } 620 if ((ret = sshbuf_dup_string(b)) == NULL) 621 fatal("%s: sshbuf_dup_string failed", __func__); 622 sshbuf_free(b); 623 debug("%s: %s", __func__, ret); 624 return ret; 625 } 626 627 static struct sshkey * 628 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh) 629 { 630 u_int i; 631 struct sshkey *key; 632 633 for (i = 0; i < options.num_host_key_files; i++) { 634 switch (type) { 635 case KEY_RSA_CERT: 636 case KEY_DSA_CERT: 637 case KEY_ECDSA_CERT: 638 case KEY_ED25519_CERT: 639 case KEY_XMSS_CERT: 640 key = sensitive_data.host_certificates[i]; 641 break; 642 default: 643 key = sensitive_data.host_keys[i]; 644 if (key == NULL && !need_private) 645 key = sensitive_data.host_pubkeys[i]; 646 break; 647 } 648 if (key != NULL && key->type == type && 649 (key->type != KEY_ECDSA || key->ecdsa_nid == nid)) 650 return need_private ? 651 sensitive_data.host_keys[i] : key; 652 } 653 return NULL; 654 } 655 656 struct sshkey * 657 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh) 658 { 659 return get_hostkey_by_type(type, nid, 0, ssh); 660 } 661 662 struct sshkey * 663 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh) 664 { 665 return get_hostkey_by_type(type, nid, 1, ssh); 666 } 667 668 struct sshkey * 669 get_hostkey_by_index(int ind) 670 { 671 if (ind < 0 || (u_int)ind >= options.num_host_key_files) 672 return (NULL); 673 return (sensitive_data.host_keys[ind]); 674 } 675 676 struct sshkey * 677 get_hostkey_public_by_index(int ind, struct ssh *ssh) 678 { 679 if (ind < 0 || (u_int)ind >= options.num_host_key_files) 680 return (NULL); 681 return (sensitive_data.host_pubkeys[ind]); 682 } 683 684 int 685 get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh) 686 { 687 u_int i; 688 689 for (i = 0; i < options.num_host_key_files; i++) { 690 if (sshkey_is_cert(key)) { 691 if (key == sensitive_data.host_certificates[i] || 692 (compare && sensitive_data.host_certificates[i] && 693 sshkey_equal(key, 694 sensitive_data.host_certificates[i]))) 695 return (i); 696 } else { 697 if (key == sensitive_data.host_keys[i] || 698 (compare && sensitive_data.host_keys[i] && 699 sshkey_equal(key, sensitive_data.host_keys[i]))) 700 return (i); 701 if (key == sensitive_data.host_pubkeys[i] || 702 (compare && sensitive_data.host_pubkeys[i] && 703 sshkey_equal(key, sensitive_data.host_pubkeys[i]))) 704 return (i); 705 } 706 } 707 return (-1); 708 } 709 710 /* Inform the client of all hostkeys */ 711 static void 712 notify_hostkeys(struct ssh *ssh) 713 { 714 struct sshbuf *buf; 715 struct sshkey *key; 716 u_int i, nkeys; 717 int r; 718 char *fp; 719 720 /* Some clients cannot cope with the hostkeys message, skip those. */ 721 if (ssh->compat & SSH_BUG_HOSTKEYS) 722 return; 723 724 if ((buf = sshbuf_new()) == NULL) 725 fatal("%s: sshbuf_new", __func__); 726 for (i = nkeys = 0; i < options.num_host_key_files; i++) { 727 key = get_hostkey_public_by_index(i, ssh); 728 if (key == NULL || key->type == KEY_UNSPEC || 729 sshkey_is_cert(key)) 730 continue; 731 fp = sshkey_fingerprint(key, options.fingerprint_hash, 732 SSH_FP_DEFAULT); 733 debug3("%s: key %d: %s %s", __func__, i, 734 sshkey_ssh_name(key), fp); 735 free(fp); 736 if (nkeys == 0) { 737 /* 738 * Start building the request when we find the 739 * first usable key. 740 */ 741 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 742 (r = sshpkt_put_cstring(ssh, "hostkeys-00@openssh.com")) != 0 || 743 (r = sshpkt_put_u8(ssh, 0)) != 0) /* want reply */ 744 sshpkt_fatal(ssh, r, "%s: start request", __func__); 745 } 746 /* Append the key to the request */ 747 sshbuf_reset(buf); 748 if ((r = sshkey_putb(key, buf)) != 0) 749 fatal("%s: couldn't put hostkey %d: %s", 750 __func__, i, ssh_err(r)); 751 if ((r = sshpkt_put_stringb(ssh, buf)) != 0) 752 sshpkt_fatal(ssh, r, "%s: append key", __func__); 753 nkeys++; 754 } 755 debug3("%s: sent %u hostkeys", __func__, nkeys); 756 if (nkeys == 0) 757 fatal("%s: no hostkeys", __func__); 758 if ((r = sshpkt_send(ssh)) != 0) 759 sshpkt_fatal(ssh, r, "%s: send", __func__); 760 sshbuf_free(buf); 761 } 762 763 /* 764 * returns 1 if connection should be dropped, 0 otherwise. 765 * dropping starts at connection #max_startups_begin with a probability 766 * of (max_startups_rate/100). the probability increases linearly until 767 * all connections are dropped for startups > max_startups 768 */ 769 static int 770 drop_connection(int startups) 771 { 772 int p, r; 773 774 if (startups < options.max_startups_begin) 775 return 0; 776 if (startups >= options.max_startups) 777 return 1; 778 if (options.max_startups_rate == 100) 779 return 1; 780 781 p = 100 - options.max_startups_rate; 782 p *= startups - options.max_startups_begin; 783 p /= options.max_startups - options.max_startups_begin; 784 p += options.max_startups_rate; 785 r = arc4random_uniform(100); 786 787 debug("drop_connection: p %d, r %d", p, r); 788 return (r < p) ? 1 : 0; 789 } 790 791 static void 792 usage(void) 793 { 794 fprintf(stderr, "%s, %s\n", 795 SSH_VERSION, 796 #ifdef WITH_OPENSSL 797 OpenSSL_version(OPENSSL_VERSION) 798 #else 799 "without OpenSSL" 800 #endif 801 ); 802 fprintf(stderr, 803 "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n" 804 " [-E log_file] [-f config_file] [-g login_grace_time]\n" 805 " [-h host_key_file] [-o option] [-p port] [-u len]\n" 806 ); 807 exit(1); 808 } 809 810 static void 811 send_rexec_state(int fd, struct sshbuf *conf) 812 { 813 struct sshbuf *m; 814 int r; 815 816 debug3("%s: entering fd = %d config len %zu", __func__, fd, 817 sshbuf_len(conf)); 818 819 /* 820 * Protocol from reexec master to child: 821 * string configuration 822 */ 823 if ((m = sshbuf_new()) == NULL) 824 fatal("%s: sshbuf_new failed", __func__); 825 if ((r = sshbuf_put_stringb(m, conf)) != 0) 826 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 827 if (ssh_msg_send(fd, 0, m) == -1) 828 fatal("%s: ssh_msg_send failed", __func__); 829 830 sshbuf_free(m); 831 832 debug3("%s: done", __func__); 833 } 834 835 static void 836 recv_rexec_state(int fd, struct sshbuf *conf) 837 { 838 struct sshbuf *m; 839 u_char *cp, ver; 840 size_t len; 841 int r; 842 843 debug3("%s: entering fd = %d", __func__, fd); 844 845 if ((m = sshbuf_new()) == NULL) 846 fatal("%s: sshbuf_new failed", __func__); 847 if (ssh_msg_recv(fd, m) == -1) 848 fatal("%s: ssh_msg_recv failed", __func__); 849 if ((r = sshbuf_get_u8(m, &ver)) != 0) 850 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 851 if (ver != 0) 852 fatal("%s: rexec version mismatch", __func__); 853 if ((r = sshbuf_get_string(m, &cp, &len)) != 0) 854 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 855 if (conf != NULL && (r = sshbuf_put(conf, cp, len))) 856 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 857 858 free(cp); 859 sshbuf_free(m); 860 861 debug3("%s: done", __func__); 862 } 863 864 /* Accept a connection from inetd */ 865 static void 866 server_accept_inetd(int *sock_in, int *sock_out) 867 { 868 int fd; 869 870 if (rexeced_flag) { 871 close(REEXEC_CONFIG_PASS_FD); 872 *sock_in = *sock_out = dup(STDIN_FILENO); 873 } else { 874 *sock_in = dup(STDIN_FILENO); 875 *sock_out = dup(STDOUT_FILENO); 876 } 877 /* 878 * We intentionally do not close the descriptors 0, 1, and 2 879 * as our code for setting the descriptors won't work if 880 * ttyfd happens to be one of those. 881 */ 882 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 883 dup2(fd, STDIN_FILENO); 884 dup2(fd, STDOUT_FILENO); 885 if (!log_stderr) 886 dup2(fd, STDERR_FILENO); 887 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO)) 888 close(fd); 889 } 890 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); 891 } 892 893 /* 894 * Listen for TCP connections 895 */ 896 static void 897 listen_on_addrs(struct listenaddr *la) 898 { 899 int ret, listen_sock; 900 struct addrinfo *ai; 901 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 902 903 for (ai = la->addrs; ai; ai = ai->ai_next) { 904 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 905 continue; 906 if (num_listen_socks >= MAX_LISTEN_SOCKS) 907 fatal("Too many listen sockets. " 908 "Enlarge MAX_LISTEN_SOCKS"); 909 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, 910 ntop, sizeof(ntop), strport, sizeof(strport), 911 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { 912 error("getnameinfo failed: %.100s", 913 ssh_gai_strerror(ret)); 914 continue; 915 } 916 /* Create socket for listening. */ 917 listen_sock = socket(ai->ai_family, ai->ai_socktype, 918 ai->ai_protocol); 919 if (listen_sock < 0) { 920 /* kernel may not support ipv6 */ 921 verbose("socket: %.100s", strerror(errno)); 922 continue; 923 } 924 if (set_nonblock(listen_sock) == -1) { 925 close(listen_sock); 926 continue; 927 } 928 if (fcntl(listen_sock, F_SETFD, FD_CLOEXEC) == -1) { 929 verbose("socket: CLOEXEC: %s", strerror(errno)); 930 close(listen_sock); 931 continue; 932 } 933 /* Socket options */ 934 set_reuseaddr(listen_sock); 935 if (la->rdomain != NULL && 936 set_rdomain(listen_sock, la->rdomain) == -1) { 937 close(listen_sock); 938 continue; 939 } 940 941 debug("Bind to port %s on %s.", strport, ntop); 942 943 /* Bind the socket to the desired port. */ 944 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { 945 error("Bind to port %s on %s failed: %.200s.", 946 strport, ntop, strerror(errno)); 947 close(listen_sock); 948 continue; 949 } 950 listen_socks[num_listen_socks] = listen_sock; 951 num_listen_socks++; 952 953 /* Start listening on the port. */ 954 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) 955 fatal("listen on [%s]:%s: %.100s", 956 ntop, strport, strerror(errno)); 957 logit("Server listening on %s port %s%s%s.", 958 ntop, strport, 959 la->rdomain == NULL ? "" : " rdomain ", 960 la->rdomain == NULL ? "" : la->rdomain); 961 } 962 } 963 964 static void 965 server_listen(void) 966 { 967 u_int i; 968 969 for (i = 0; i < options.num_listen_addrs; i++) { 970 listen_on_addrs(&options.listen_addrs[i]); 971 freeaddrinfo(options.listen_addrs[i].addrs); 972 free(options.listen_addrs[i].rdomain); 973 memset(&options.listen_addrs[i], 0, 974 sizeof(options.listen_addrs[i])); 975 } 976 free(options.listen_addrs); 977 options.listen_addrs = NULL; 978 options.num_listen_addrs = 0; 979 980 if (!num_listen_socks) 981 fatal("Cannot bind any address."); 982 } 983 984 /* 985 * The main TCP accept loop. Note that, for the non-debug case, returns 986 * from this function are in a forked subprocess. 987 */ 988 static void 989 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) 990 { 991 fd_set *fdset; 992 int i, j, ret, maxfd; 993 int startups = 0, listening = 0, lameduck = 0; 994 int startup_p[2] = { -1 , -1 }; 995 char c = 0; 996 struct sockaddr_storage from; 997 socklen_t fromlen; 998 pid_t pid; 999 1000 /* setup fd set for accept */ 1001 fdset = NULL; 1002 maxfd = 0; 1003 for (i = 0; i < num_listen_socks; i++) 1004 if (listen_socks[i] > maxfd) 1005 maxfd = listen_socks[i]; 1006 /* pipes connected to unauthenticated childs */ 1007 startup_pipes = xcalloc(options.max_startups, sizeof(int)); 1008 startup_flags = xcalloc(options.max_startups, sizeof(int)); 1009 for (i = 0; i < options.max_startups; i++) 1010 startup_pipes[i] = -1; 1011 1012 /* 1013 * Stay listening for connections until the system crashes or 1014 * the daemon is killed with a signal. 1015 */ 1016 for (;;) { 1017 if (received_sighup) { 1018 if (!lameduck) { 1019 debug("Received SIGHUP; waiting for children"); 1020 close_listen_socks(); 1021 lameduck = 1; 1022 } 1023 if (listening <= 0) 1024 sighup_restart(); 1025 } 1026 free(fdset); 1027 fdset = xcalloc(howmany(maxfd + 1, NFDBITS), 1028 sizeof(fd_mask)); 1029 1030 for (i = 0; i < num_listen_socks; i++) 1031 FD_SET(listen_socks[i], fdset); 1032 for (i = 0; i < options.max_startups; i++) 1033 if (startup_pipes[i] != -1) 1034 FD_SET(startup_pipes[i], fdset); 1035 1036 /* Wait in select until there is a connection. */ 1037 ret = select(maxfd+1, fdset, NULL, NULL, NULL); 1038 if (ret < 0 && errno != EINTR) 1039 error("select: %.100s", strerror(errno)); 1040 if (received_sigterm) { 1041 logit("Received signal %d; terminating.", 1042 (int) received_sigterm); 1043 close_listen_socks(); 1044 if (options.pid_file != NULL) 1045 unlink(options.pid_file); 1046 exit(received_sigterm == SIGTERM ? 0 : 255); 1047 } 1048 if (ret < 0) 1049 continue; 1050 1051 for (i = 0; i < options.max_startups; i++) { 1052 if (startup_pipes[i] == -1 || 1053 !FD_ISSET(startup_pipes[i], fdset)) 1054 continue; 1055 switch (read(startup_pipes[i], &c, sizeof(c))) { 1056 case -1: 1057 if (errno == EINTR || errno == EAGAIN) 1058 continue; 1059 if (errno != EPIPE) { 1060 error("%s: startup pipe %d (fd=%d): " 1061 "read %s", __func__, i, 1062 startup_pipes[i], strerror(errno)); 1063 } 1064 /* FALLTHROUGH */ 1065 case 0: 1066 /* child exited or completed auth */ 1067 close(startup_pipes[i]); 1068 startup_pipes[i] = -1; 1069 startups--; 1070 if (startup_flags[i]) 1071 listening--; 1072 break; 1073 case 1: 1074 /* child has finished preliminaries */ 1075 if (startup_flags[i]) { 1076 listening--; 1077 startup_flags[i] = 0; 1078 } 1079 break; 1080 } 1081 } 1082 for (i = 0; i < num_listen_socks; i++) { 1083 if (!FD_ISSET(listen_socks[i], fdset)) 1084 continue; 1085 fromlen = sizeof(from); 1086 *newsock = accept(listen_socks[i], 1087 (struct sockaddr *)&from, &fromlen); 1088 if (*newsock < 0) { 1089 if (errno != EINTR && errno != EWOULDBLOCK && 1090 errno != ECONNABORTED) 1091 error("accept: %.100s", 1092 strerror(errno)); 1093 if (errno == EMFILE || errno == ENFILE) 1094 usleep(100 * 1000); 1095 continue; 1096 } 1097 if (unset_nonblock(*newsock) == -1) { 1098 close(*newsock); 1099 continue; 1100 } 1101 if (drop_connection(startups) == 1) { 1102 char *laddr = get_local_ipaddr(*newsock); 1103 char *raddr = get_peer_ipaddr(*newsock); 1104 1105 verbose("drop connection #%d from [%s]:%d " 1106 "on [%s]:%d past MaxStartups", startups, 1107 raddr, get_peer_port(*newsock), 1108 laddr, get_local_port(*newsock)); 1109 free(laddr); 1110 free(raddr); 1111 close(*newsock); 1112 continue; 1113 } 1114 if (pipe(startup_p) == -1) { 1115 close(*newsock); 1116 continue; 1117 } 1118 1119 if (rexec_flag && socketpair(AF_UNIX, 1120 SOCK_STREAM, 0, config_s) == -1) { 1121 error("reexec socketpair: %s", 1122 strerror(errno)); 1123 close(*newsock); 1124 close(startup_p[0]); 1125 close(startup_p[1]); 1126 continue; 1127 } 1128 1129 for (j = 0; j < options.max_startups; j++) 1130 if (startup_pipes[j] == -1) { 1131 startup_pipes[j] = startup_p[0]; 1132 if (maxfd < startup_p[0]) 1133 maxfd = startup_p[0]; 1134 startups++; 1135 startup_flags[j] = 1; 1136 break; 1137 } 1138 1139 /* 1140 * Got connection. Fork a child to handle it, unless 1141 * we are in debugging mode. 1142 */ 1143 if (debug_flag) { 1144 /* 1145 * In debugging mode. Close the listening 1146 * socket, and start processing the 1147 * connection without forking. 1148 */ 1149 debug("Server will not fork when running in debugging mode."); 1150 close_listen_socks(); 1151 *sock_in = *newsock; 1152 *sock_out = *newsock; 1153 close(startup_p[0]); 1154 close(startup_p[1]); 1155 startup_pipe = -1; 1156 pid = getpid(); 1157 if (rexec_flag) { 1158 send_rexec_state(config_s[0], cfg); 1159 close(config_s[0]); 1160 } 1161 return; 1162 } 1163 1164 /* 1165 * Normal production daemon. Fork, and have 1166 * the child process the connection. The 1167 * parent continues listening. 1168 */ 1169 listening++; 1170 if ((pid = fork()) == 0) { 1171 /* 1172 * Child. Close the listening and 1173 * max_startup sockets. Start using 1174 * the accepted socket. Reinitialize 1175 * logging (since our pid has changed). 1176 * We return from this function to handle 1177 * the connection. 1178 */ 1179 startup_pipe = startup_p[1]; 1180 close_startup_pipes(); 1181 close_listen_socks(); 1182 *sock_in = *newsock; 1183 *sock_out = *newsock; 1184 log_init(__progname, 1185 options.log_level, 1186 options.log_facility, 1187 log_stderr); 1188 if (rexec_flag) 1189 close(config_s[0]); 1190 else { 1191 /* 1192 * Signal parent that the preliminaries 1193 * for this child are complete. For the 1194 * re-exec case, this happens after the 1195 * child has received the rexec state 1196 * from the server. 1197 */ 1198 (void)atomicio(vwrite, startup_pipe, 1199 "\0", 1); 1200 } 1201 return; 1202 } 1203 1204 /* Parent. Stay in the loop. */ 1205 if (pid < 0) 1206 error("fork: %.100s", strerror(errno)); 1207 else 1208 debug("Forked child %ld.", (long)pid); 1209 1210 close(startup_p[1]); 1211 1212 if (rexec_flag) { 1213 send_rexec_state(config_s[0], cfg); 1214 close(config_s[0]); 1215 close(config_s[1]); 1216 } 1217 close(*newsock); 1218 } 1219 } 1220 } 1221 1222 /* 1223 * If IP options are supported, make sure there are none (log and 1224 * return an error if any are found). Basically we are worried about 1225 * source routing; it can be used to pretend you are somebody 1226 * (ip-address) you are not. That itself may be "almost acceptable" 1227 * under certain circumstances, but rhosts authentication is useless 1228 * if source routing is accepted. Notice also that if we just dropped 1229 * source routing here, the other side could use IP spoofing to do 1230 * rest of the interaction and could still bypass security. So we 1231 * exit here if we detect any IP options. 1232 */ 1233 static void 1234 check_ip_options(struct ssh *ssh) 1235 { 1236 int sock_in = ssh_packet_get_connection_in(ssh); 1237 struct sockaddr_storage from; 1238 u_char opts[200]; 1239 socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from); 1240 char text[sizeof(opts) * 3 + 1]; 1241 1242 memset(&from, 0, sizeof(from)); 1243 if (getpeername(sock_in, (struct sockaddr *)&from, 1244 &fromlen) < 0) 1245 return; 1246 if (from.ss_family != AF_INET) 1247 return; 1248 /* XXX IPv6 options? */ 1249 1250 if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts, 1251 &option_size) >= 0 && option_size != 0) { 1252 text[0] = '\0'; 1253 for (i = 0; i < option_size; i++) 1254 snprintf(text + i*3, sizeof(text) - i*3, 1255 " %2.2x", opts[i]); 1256 fatal("Connection from %.100s port %d with IP opts: %.800s", 1257 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text); 1258 } 1259 return; 1260 } 1261 1262 /* Set the routing domain for this process */ 1263 static void 1264 set_process_rdomain(struct ssh *ssh, const char *name) 1265 { 1266 int rtable, ortable = getrtable(); 1267 const char *errstr; 1268 1269 if (name == NULL) 1270 return; /* default */ 1271 1272 if (strcmp(name, "%D") == 0) { 1273 /* "expands" to routing domain of connection */ 1274 if ((name = ssh_packet_rdomain_in(ssh)) == NULL) 1275 return; 1276 } 1277 1278 rtable = (int)strtonum(name, 0, 255, &errstr); 1279 if (errstr != NULL) /* Shouldn't happen */ 1280 fatal("Invalid routing domain \"%s\": %s", name, errstr); 1281 if (rtable != ortable && setrtable(rtable) != 0) 1282 fatal("Unable to set routing domain %d: %s", 1283 rtable, strerror(errno)); 1284 debug("%s: set routing domain %d (was %d)", __func__, rtable, ortable); 1285 } 1286 1287 static void 1288 accumulate_host_timing_secret(struct sshbuf *server_cfg, 1289 const struct sshkey *key) 1290 { 1291 static struct ssh_digest_ctx *ctx; 1292 u_char *hash; 1293 size_t len; 1294 struct sshbuf *buf; 1295 int r; 1296 1297 if (ctx == NULL && (ctx = ssh_digest_start(SSH_DIGEST_SHA512)) == NULL) 1298 fatal("%s: ssh_digest_start", __func__); 1299 if (key == NULL) { /* finalize */ 1300 /* add server config in case we are using agent for host keys */ 1301 if (ssh_digest_update(ctx, sshbuf_ptr(server_cfg), 1302 sshbuf_len(server_cfg)) != 0) 1303 fatal("%s: ssh_digest_update", __func__); 1304 len = ssh_digest_bytes(SSH_DIGEST_SHA512); 1305 hash = xmalloc(len); 1306 if (ssh_digest_final(ctx, hash, len) != 0) 1307 fatal("%s: ssh_digest_final", __func__); 1308 options.timing_secret = PEEK_U64(hash); 1309 freezero(hash, len); 1310 ssh_digest_free(ctx); 1311 ctx = NULL; 1312 return; 1313 } 1314 if ((buf = sshbuf_new()) == NULL) 1315 fatal("%s could not allocate buffer", __func__); 1316 if ((r = sshkey_private_serialize(key, buf)) != 0) 1317 fatal("sshkey_private_serialize: %s", ssh_err(r)); 1318 if (ssh_digest_update(ctx, sshbuf_ptr(buf), sshbuf_len(buf)) != 0) 1319 fatal("%s: ssh_digest_update", __func__); 1320 sshbuf_reset(buf); 1321 sshbuf_free(buf); 1322 } 1323 1324 /* 1325 * Main program for the daemon. 1326 */ 1327 int 1328 main(int ac, char **av) 1329 { 1330 struct ssh *ssh = NULL; 1331 extern char *optarg; 1332 extern int optind; 1333 int r, opt, on = 1, already_daemon, remote_port; 1334 int sock_in = -1, sock_out = -1, newsock = -1; 1335 const char *remote_ip, *rdomain; 1336 char *fp, *line, *laddr, *logfile = NULL; 1337 int config_s[2] = { -1 , -1 }; 1338 u_int i, j; 1339 u_int64_t ibytes, obytes; 1340 mode_t new_umask; 1341 struct sshkey *key; 1342 struct sshkey *pubkey; 1343 int keytype; 1344 Authctxt *authctxt; 1345 struct connection_info *connection_info = NULL; 1346 1347 ssh_malloc_init(); /* must be called before any mallocs */ 1348 /* Save argv. */ 1349 saved_argv = av; 1350 rexec_argc = ac; 1351 1352 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1353 sanitise_stdfd(); 1354 1355 /* Initialize configuration options to their default values. */ 1356 initialize_server_options(&options); 1357 1358 /* Parse command-line arguments. */ 1359 while ((opt = getopt(ac, av, 1360 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) { 1361 switch (opt) { 1362 case '4': 1363 options.address_family = AF_INET; 1364 break; 1365 case '6': 1366 options.address_family = AF_INET6; 1367 break; 1368 case 'f': 1369 config_file_name = optarg; 1370 break; 1371 case 'c': 1372 servconf_add_hostcert("[command-line]", 0, 1373 &options, optarg); 1374 break; 1375 case 'd': 1376 if (debug_flag == 0) { 1377 debug_flag = 1; 1378 options.log_level = SYSLOG_LEVEL_DEBUG1; 1379 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) 1380 options.log_level++; 1381 break; 1382 case 'D': 1383 no_daemon_flag = 1; 1384 break; 1385 case 'E': 1386 logfile = optarg; 1387 /* FALLTHROUGH */ 1388 case 'e': 1389 log_stderr = 1; 1390 break; 1391 case 'i': 1392 inetd_flag = 1; 1393 break; 1394 case 'r': 1395 rexec_flag = 0; 1396 break; 1397 case 'R': 1398 rexeced_flag = 1; 1399 inetd_flag = 1; 1400 break; 1401 case 'Q': 1402 /* ignored */ 1403 break; 1404 case 'q': 1405 options.log_level = SYSLOG_LEVEL_QUIET; 1406 break; 1407 case 'b': 1408 /* protocol 1, ignored */ 1409 break; 1410 case 'p': 1411 options.ports_from_cmdline = 1; 1412 if (options.num_ports >= MAX_PORTS) { 1413 fprintf(stderr, "too many ports.\n"); 1414 exit(1); 1415 } 1416 options.ports[options.num_ports++] = a2port(optarg); 1417 if (options.ports[options.num_ports-1] <= 0) { 1418 fprintf(stderr, "Bad port number.\n"); 1419 exit(1); 1420 } 1421 break; 1422 case 'g': 1423 if ((options.login_grace_time = convtime(optarg)) == -1) { 1424 fprintf(stderr, "Invalid login grace time.\n"); 1425 exit(1); 1426 } 1427 break; 1428 case 'k': 1429 /* protocol 1, ignored */ 1430 break; 1431 case 'h': 1432 servconf_add_hostkey("[command-line]", 0, 1433 &options, optarg, 1); 1434 break; 1435 case 't': 1436 test_flag = 1; 1437 break; 1438 case 'T': 1439 test_flag = 2; 1440 break; 1441 case 'C': 1442 connection_info = get_connection_info(ssh, 0, 0); 1443 if (parse_server_match_testspec(connection_info, 1444 optarg) == -1) 1445 exit(1); 1446 break; 1447 case 'u': 1448 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL); 1449 if (utmp_len > HOST_NAME_MAX+1) { 1450 fprintf(stderr, "Invalid utmp length.\n"); 1451 exit(1); 1452 } 1453 break; 1454 case 'o': 1455 line = xstrdup(optarg); 1456 if (process_server_config_line(&options, line, 1457 "command-line", 0, NULL, NULL) != 0) 1458 exit(1); 1459 free(line); 1460 break; 1461 case '?': 1462 default: 1463 usage(); 1464 break; 1465 } 1466 } 1467 if (rexeced_flag || inetd_flag) 1468 rexec_flag = 0; 1469 if (!test_flag && rexec_flag && !path_absolute(av[0])) 1470 fatal("sshd re-exec requires execution with an absolute path"); 1471 if (rexeced_flag) 1472 closefrom(REEXEC_MIN_FREE_FD); 1473 else 1474 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); 1475 1476 #ifdef WITH_OPENSSL 1477 OpenSSL_add_all_algorithms(); 1478 #endif 1479 1480 /* If requested, redirect the logs to the specified logfile. */ 1481 if (logfile != NULL) 1482 log_redirect_stderr_to(logfile); 1483 /* 1484 * Force logging to stderr until we have loaded the private host 1485 * key (unless started from inetd) 1486 */ 1487 log_init(__progname, 1488 options.log_level == SYSLOG_LEVEL_NOT_SET ? 1489 SYSLOG_LEVEL_INFO : options.log_level, 1490 options.log_facility == SYSLOG_FACILITY_NOT_SET ? 1491 SYSLOG_FACILITY_AUTH : options.log_facility, 1492 log_stderr || !inetd_flag); 1493 1494 sensitive_data.have_ssh2_key = 0; 1495 1496 /* 1497 * If we're not doing an extended test do not silently ignore connection 1498 * test params. 1499 */ 1500 if (test_flag < 2 && connection_info != NULL) 1501 fatal("Config test connection parameter (-C) provided without " 1502 "test mode (-T)"); 1503 1504 /* Fetch our configuration */ 1505 if ((cfg = sshbuf_new()) == NULL) 1506 fatal("%s: sshbuf_new failed", __func__); 1507 if (rexeced_flag) { 1508 recv_rexec_state(REEXEC_CONFIG_PASS_FD, cfg); 1509 if (!debug_flag) { 1510 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); 1511 close(REEXEC_STARTUP_PIPE_FD); 1512 /* 1513 * Signal parent that this child is at a point where 1514 * they can go away if they have a SIGHUP pending. 1515 */ 1516 (void)atomicio(vwrite, startup_pipe, "\0", 1); 1517 } 1518 } 1519 else if (strcasecmp(config_file_name, "none") != 0) 1520 load_server_config(config_file_name, cfg); 1521 1522 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, 1523 cfg, NULL); 1524 1525 /* Fill in default values for those options not explicitly set. */ 1526 fill_default_server_options(&options); 1527 1528 /* challenge-response is implemented via keyboard interactive */ 1529 if (options.challenge_response_authentication) 1530 options.kbd_interactive_authentication = 1; 1531 1532 /* Check that options are sensible */ 1533 if (options.authorized_keys_command_user == NULL && 1534 (options.authorized_keys_command != NULL && 1535 strcasecmp(options.authorized_keys_command, "none") != 0)) 1536 fatal("AuthorizedKeysCommand set without " 1537 "AuthorizedKeysCommandUser"); 1538 if (options.authorized_principals_command_user == NULL && 1539 (options.authorized_principals_command != NULL && 1540 strcasecmp(options.authorized_principals_command, "none") != 0)) 1541 fatal("AuthorizedPrincipalsCommand set without " 1542 "AuthorizedPrincipalsCommandUser"); 1543 1544 /* 1545 * Check whether there is any path through configured auth methods. 1546 * Unfortunately it is not possible to verify this generally before 1547 * daemonisation in the presence of Match block, but this catches 1548 * and warns for trivial misconfigurations that could break login. 1549 */ 1550 if (options.num_auth_methods != 0) { 1551 for (i = 0; i < options.num_auth_methods; i++) { 1552 if (auth2_methods_valid(options.auth_methods[i], 1553 1) == 0) 1554 break; 1555 } 1556 if (i >= options.num_auth_methods) 1557 fatal("AuthenticationMethods cannot be satisfied by " 1558 "enabled authentication methods"); 1559 } 1560 1561 /* Check that there are no remaining arguments. */ 1562 if (optind < ac) { 1563 fprintf(stderr, "Extra argument %s.\n", av[optind]); 1564 exit(1); 1565 } 1566 1567 debug("sshd version %s, %s", SSH_VERSION, 1568 #ifdef WITH_OPENSSL 1569 OpenSSL_version(OPENSSL_VERSION) 1570 #else 1571 "without OpenSSL" 1572 #endif 1573 ); 1574 1575 /* load host keys */ 1576 sensitive_data.host_keys = xcalloc(options.num_host_key_files, 1577 sizeof(struct sshkey *)); 1578 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files, 1579 sizeof(struct sshkey *)); 1580 1581 if (options.host_key_agent) { 1582 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME)) 1583 setenv(SSH_AUTHSOCKET_ENV_NAME, 1584 options.host_key_agent, 1); 1585 if ((r = ssh_get_authentication_socket(NULL)) == 0) 1586 have_agent = 1; 1587 else 1588 error("Could not connect to agent \"%s\": %s", 1589 options.host_key_agent, ssh_err(r)); 1590 } 1591 1592 for (i = 0; i < options.num_host_key_files; i++) { 1593 int ll = options.host_key_file_userprovided[i] ? 1594 SYSLOG_LEVEL_ERROR : SYSLOG_LEVEL_DEBUG1; 1595 1596 if (options.host_key_files[i] == NULL) 1597 continue; 1598 if ((r = sshkey_load_private(options.host_key_files[i], "", 1599 &key, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR) 1600 do_log2(ll, "Unable to load host key \"%s\": %s", 1601 options.host_key_files[i], ssh_err(r)); 1602 if ((r = sshkey_load_public(options.host_key_files[i], 1603 &pubkey, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR) 1604 do_log2(ll, "Unable to load host key \"%s\": %s", 1605 options.host_key_files[i], ssh_err(r)); 1606 if (pubkey == NULL && key != NULL) 1607 if ((r = sshkey_from_private(key, &pubkey)) != 0) 1608 fatal("Could not demote key: \"%s\": %s", 1609 options.host_key_files[i], ssh_err(r)); 1610 sensitive_data.host_keys[i] = key; 1611 sensitive_data.host_pubkeys[i] = pubkey; 1612 1613 if (key == NULL && pubkey != NULL && have_agent) { 1614 debug("will rely on agent for hostkey %s", 1615 options.host_key_files[i]); 1616 keytype = pubkey->type; 1617 } else if (key != NULL) { 1618 keytype = key->type; 1619 accumulate_host_timing_secret(cfg, key); 1620 } else { 1621 do_log2(ll, "Unable to load host key: %s", 1622 options.host_key_files[i]); 1623 sensitive_data.host_keys[i] = NULL; 1624 sensitive_data.host_pubkeys[i] = NULL; 1625 continue; 1626 } 1627 1628 switch (keytype) { 1629 case KEY_RSA: 1630 case KEY_DSA: 1631 case KEY_ECDSA: 1632 case KEY_ED25519: 1633 case KEY_XMSS: 1634 if (have_agent || key != NULL) 1635 sensitive_data.have_ssh2_key = 1; 1636 break; 1637 } 1638 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash, 1639 SSH_FP_DEFAULT)) == NULL) 1640 fatal("sshkey_fingerprint failed"); 1641 debug("%s host key #%d: %s %s", 1642 key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp); 1643 free(fp); 1644 } 1645 accumulate_host_timing_secret(cfg, NULL); 1646 if (!sensitive_data.have_ssh2_key) { 1647 logit("sshd: no hostkeys available -- exiting."); 1648 exit(1); 1649 } 1650 1651 /* 1652 * Load certificates. They are stored in an array at identical 1653 * indices to the public keys that they relate to. 1654 */ 1655 sensitive_data.host_certificates = xcalloc(options.num_host_key_files, 1656 sizeof(struct sshkey *)); 1657 for (i = 0; i < options.num_host_key_files; i++) 1658 sensitive_data.host_certificates[i] = NULL; 1659 1660 for (i = 0; i < options.num_host_cert_files; i++) { 1661 if (options.host_cert_files[i] == NULL) 1662 continue; 1663 if ((r = sshkey_load_public(options.host_cert_files[i], 1664 &key, NULL)) != 0) { 1665 error("Could not load host certificate \"%s\": %s", 1666 options.host_cert_files[i], ssh_err(r)); 1667 continue; 1668 } 1669 if (!sshkey_is_cert(key)) { 1670 error("Certificate file is not a certificate: %s", 1671 options.host_cert_files[i]); 1672 sshkey_free(key); 1673 continue; 1674 } 1675 /* Find matching private key */ 1676 for (j = 0; j < options.num_host_key_files; j++) { 1677 if (sshkey_equal_public(key, 1678 sensitive_data.host_keys[j])) { 1679 sensitive_data.host_certificates[j] = key; 1680 break; 1681 } 1682 } 1683 if (j >= options.num_host_key_files) { 1684 error("No matching private key for certificate: %s", 1685 options.host_cert_files[i]); 1686 sshkey_free(key); 1687 continue; 1688 } 1689 sensitive_data.host_certificates[j] = key; 1690 debug("host certificate: #%u type %d %s", j, key->type, 1691 sshkey_type(key)); 1692 } 1693 1694 if (use_privsep) { 1695 struct stat st; 1696 1697 if (getpwnam(SSH_PRIVSEP_USER) == NULL) 1698 fatal("Privilege separation user %s does not exist", 1699 SSH_PRIVSEP_USER); 1700 endpwent(); 1701 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || 1702 (S_ISDIR(st.st_mode) == 0)) 1703 fatal("Missing privilege separation directory: %s", 1704 _PATH_PRIVSEP_CHROOT_DIR); 1705 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) 1706 fatal("%s must be owned by root and not group or " 1707 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); 1708 } 1709 1710 if (test_flag > 1) { 1711 /* 1712 * If no connection info was provided by -C then use 1713 * use a blank one that will cause no predicate to match. 1714 */ 1715 if (connection_info == NULL) 1716 connection_info = get_connection_info(ssh, 0, 0); 1717 connection_info->test = 1; 1718 parse_server_match_config(&options, connection_info); 1719 dump_config(&options); 1720 } 1721 1722 /* Configuration looks good, so exit if in test mode. */ 1723 if (test_flag) 1724 exit(0); 1725 1726 if (rexec_flag) { 1727 if (rexec_argc < 0) 1728 fatal("rexec_argc %d < 0", rexec_argc); 1729 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); 1730 for (i = 0; i < (u_int)rexec_argc; i++) { 1731 debug("rexec_argv[%d]='%s'", i, saved_argv[i]); 1732 rexec_argv[i] = saved_argv[i]; 1733 } 1734 rexec_argv[rexec_argc] = "-R"; 1735 rexec_argv[rexec_argc + 1] = NULL; 1736 } 1737 1738 /* Ensure that umask disallows at least group and world write */ 1739 new_umask = umask(0077) | 0022; 1740 (void) umask(new_umask); 1741 1742 /* Initialize the log (it is reinitialized below in case we forked). */ 1743 if (debug_flag && (!inetd_flag || rexeced_flag)) 1744 log_stderr = 1; 1745 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1746 1747 /* 1748 * If not in debugging mode, not started from inetd and not already 1749 * daemonized (eg re-exec via SIGHUP), disconnect from the controlling 1750 * terminal, and fork. The original process exits. 1751 */ 1752 already_daemon = daemonized(); 1753 if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) { 1754 1755 if (daemon(0, 0) < 0) 1756 fatal("daemon() failed: %.200s", strerror(errno)); 1757 1758 disconnect_controlling_tty(); 1759 } 1760 /* Reinitialize the log (because of the fork above). */ 1761 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1762 1763 /* Chdir to the root directory so that the current disk can be 1764 unmounted if desired. */ 1765 if (chdir("/") == -1) 1766 error("chdir(\"/\"): %s", strerror(errno)); 1767 1768 /* ignore SIGPIPE */ 1769 signal(SIGPIPE, SIG_IGN); 1770 1771 /* Get a connection, either from inetd or a listening TCP socket */ 1772 if (inetd_flag) { 1773 server_accept_inetd(&sock_in, &sock_out); 1774 } else { 1775 server_listen(); 1776 1777 signal(SIGHUP, sighup_handler); 1778 signal(SIGCHLD, main_sigchld_handler); 1779 signal(SIGTERM, sigterm_handler); 1780 signal(SIGQUIT, sigterm_handler); 1781 1782 /* 1783 * Write out the pid file after the sigterm handler 1784 * is setup and the listen sockets are bound 1785 */ 1786 if (options.pid_file != NULL && !debug_flag) { 1787 FILE *f = fopen(options.pid_file, "w"); 1788 1789 if (f == NULL) { 1790 error("Couldn't create pid file \"%s\": %s", 1791 options.pid_file, strerror(errno)); 1792 } else { 1793 fprintf(f, "%ld\n", (long) getpid()); 1794 fclose(f); 1795 } 1796 } 1797 1798 /* Accept a connection and return in a forked child */ 1799 server_accept_loop(&sock_in, &sock_out, 1800 &newsock, config_s); 1801 } 1802 1803 /* This is the child processing a new connection. */ 1804 setproctitle("%s", "[accepted]"); 1805 1806 /* 1807 * Create a new session and process group since the 4.4BSD 1808 * setlogin() affects the entire process group. We don't 1809 * want the child to be able to affect the parent. 1810 */ 1811 if (!debug_flag && !inetd_flag && setsid() < 0) 1812 error("setsid: %.100s", strerror(errno)); 1813 1814 if (rexec_flag) { 1815 int fd; 1816 1817 debug("rexec start in %d out %d newsock %d pipe %d sock %d", 1818 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 1819 dup2(newsock, STDIN_FILENO); 1820 dup2(STDIN_FILENO, STDOUT_FILENO); 1821 if (startup_pipe == -1) 1822 close(REEXEC_STARTUP_PIPE_FD); 1823 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) { 1824 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); 1825 close(startup_pipe); 1826 startup_pipe = REEXEC_STARTUP_PIPE_FD; 1827 } 1828 1829 dup2(config_s[1], REEXEC_CONFIG_PASS_FD); 1830 close(config_s[1]); 1831 1832 execv(rexec_argv[0], rexec_argv); 1833 1834 /* Reexec has failed, fall back and continue */ 1835 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); 1836 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); 1837 log_init(__progname, options.log_level, 1838 options.log_facility, log_stderr); 1839 1840 /* Clean up fds */ 1841 close(REEXEC_CONFIG_PASS_FD); 1842 newsock = sock_out = sock_in = dup(STDIN_FILENO); 1843 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1844 dup2(fd, STDIN_FILENO); 1845 dup2(fd, STDOUT_FILENO); 1846 if (fd > STDERR_FILENO) 1847 close(fd); 1848 } 1849 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", 1850 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 1851 } 1852 1853 /* Executed child processes don't need these. */ 1854 fcntl(sock_out, F_SETFD, FD_CLOEXEC); 1855 fcntl(sock_in, F_SETFD, FD_CLOEXEC); 1856 1857 /* 1858 * Disable the key regeneration alarm. We will not regenerate the 1859 * key since we are no longer in a position to give it to anyone. We 1860 * will not restart on SIGHUP since it no longer makes sense. 1861 */ 1862 alarm(0); 1863 signal(SIGALRM, SIG_DFL); 1864 signal(SIGHUP, SIG_DFL); 1865 signal(SIGTERM, SIG_DFL); 1866 signal(SIGQUIT, SIG_DFL); 1867 signal(SIGCHLD, SIG_DFL); 1868 1869 /* 1870 * Register our connection. This turns encryption off because we do 1871 * not have a key. 1872 */ 1873 if ((ssh = ssh_packet_set_connection(NULL, sock_in, sock_out)) == NULL) 1874 fatal("Unable to create connection"); 1875 the_active_state = ssh; 1876 ssh_packet_set_server(ssh); 1877 1878 check_ip_options(ssh); 1879 1880 /* Prepare the channels layer */ 1881 channel_init_channels(ssh); 1882 channel_set_af(ssh, options.address_family); 1883 process_permitopen(ssh, &options); 1884 1885 /* Set SO_KEEPALIVE if requested. */ 1886 if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) && 1887 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) 1888 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 1889 1890 if ((remote_port = ssh_remote_port(ssh)) < 0) { 1891 debug("ssh_remote_port failed"); 1892 cleanup_exit(255); 1893 } 1894 1895 /* 1896 * The rest of the code depends on the fact that 1897 * ssh_remote_ipaddr() caches the remote ip, even if 1898 * the socket goes away. 1899 */ 1900 remote_ip = ssh_remote_ipaddr(ssh); 1901 1902 rdomain = ssh_packet_rdomain_in(ssh); 1903 1904 /* Log the connection. */ 1905 laddr = get_local_ipaddr(sock_in); 1906 verbose("Connection from %s port %d on %s port %d%s%s%s", 1907 remote_ip, remote_port, laddr, ssh_local_port(ssh), 1908 rdomain == NULL ? "" : " rdomain \"", 1909 rdomain == NULL ? "" : rdomain, 1910 rdomain == NULL ? "" : "\""); 1911 free(laddr); 1912 1913 /* 1914 * We don't want to listen forever unless the other side 1915 * successfully authenticates itself. So we set up an alarm which is 1916 * cleared after successful authentication. A limit of zero 1917 * indicates no limit. Note that we don't set the alarm in debugging 1918 * mode; it is just annoying to have the server exit just when you 1919 * are about to discover the bug. 1920 */ 1921 signal(SIGALRM, grace_alarm_handler); 1922 if (!debug_flag) 1923 alarm(options.login_grace_time); 1924 1925 if (kex_exchange_identification(ssh, -1, options.version_addendum) != 0) 1926 cleanup_exit(255); /* error already logged */ 1927 1928 ssh_packet_set_nonblocking(ssh); 1929 1930 /* allocate authentication context */ 1931 authctxt = xcalloc(1, sizeof(*authctxt)); 1932 ssh->authctxt = authctxt; 1933 1934 /* XXX global for cleanup, access from other modules */ 1935 the_authctxt = authctxt; 1936 1937 /* Set default key authentication options */ 1938 if ((auth_opts = sshauthopt_new_with_keys_defaults()) == NULL) 1939 fatal("allocation failed"); 1940 1941 /* prepare buffer to collect messages to display to user after login */ 1942 if ((loginmsg = sshbuf_new()) == NULL) 1943 fatal("%s: sshbuf_new failed", __func__); 1944 auth_debug_reset(); 1945 1946 if (use_privsep) { 1947 if (privsep_preauth(ssh) == 1) 1948 goto authenticated; 1949 } else if (have_agent) { 1950 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { 1951 error("Unable to get agent socket: %s", ssh_err(r)); 1952 have_agent = 0; 1953 } 1954 } 1955 1956 /* perform the key exchange */ 1957 /* authenticate user and start session */ 1958 do_ssh2_kex(ssh); 1959 do_authentication2(ssh); 1960 1961 /* 1962 * If we use privilege separation, the unprivileged child transfers 1963 * the current keystate and exits 1964 */ 1965 if (use_privsep) { 1966 mm_send_keystate(ssh, pmonitor); 1967 ssh_packet_clear_keys(ssh); 1968 exit(0); 1969 } 1970 1971 authenticated: 1972 /* 1973 * Cancel the alarm we set to limit the time taken for 1974 * authentication. 1975 */ 1976 alarm(0); 1977 signal(SIGALRM, SIG_DFL); 1978 authctxt->authenticated = 1; 1979 if (startup_pipe != -1) { 1980 close(startup_pipe); 1981 startup_pipe = -1; 1982 } 1983 1984 if (options.routing_domain != NULL) 1985 set_process_rdomain(ssh, options.routing_domain); 1986 1987 /* 1988 * In privilege separation, we fork another child and prepare 1989 * file descriptor passing. 1990 */ 1991 if (use_privsep) { 1992 privsep_postauth(ssh, authctxt); 1993 /* the monitor process [priv] will not return */ 1994 } 1995 1996 ssh_packet_set_timeout(ssh, options.client_alive_interval, 1997 options.client_alive_count_max); 1998 1999 /* Try to send all our hostkeys to the client */ 2000 notify_hostkeys(ssh); 2001 2002 /* Start session. */ 2003 do_authenticated(ssh, authctxt); 2004 2005 /* The connection has been terminated. */ 2006 ssh_packet_get_bytes(ssh, &ibytes, &obytes); 2007 verbose("Transferred: sent %llu, received %llu bytes", 2008 (unsigned long long)obytes, (unsigned long long)ibytes); 2009 2010 verbose("Closing connection to %.500s port %d", remote_ip, remote_port); 2011 ssh_packet_close(ssh); 2012 2013 if (use_privsep) 2014 mm_terminate(); 2015 2016 exit(0); 2017 } 2018 2019 int 2020 sshd_hostkey_sign(struct ssh *ssh, struct sshkey *privkey, 2021 struct sshkey *pubkey, u_char **signature, size_t *slenp, 2022 const u_char *data, size_t dlen, const char *alg) 2023 { 2024 int r; 2025 2026 if (use_privsep) { 2027 if (privkey) { 2028 if (mm_sshkey_sign(ssh, privkey, signature, slenp, 2029 data, dlen, alg, ssh->compat) < 0) 2030 fatal("%s: privkey sign failed", __func__); 2031 } else { 2032 if (mm_sshkey_sign(ssh, pubkey, signature, slenp, 2033 data, dlen, alg, ssh->compat) < 0) 2034 fatal("%s: pubkey sign failed", __func__); 2035 } 2036 } else { 2037 if (privkey) { 2038 if (sshkey_sign(privkey, signature, slenp, data, dlen, 2039 alg, ssh->compat) < 0) 2040 fatal("%s: privkey sign failed", __func__); 2041 } else { 2042 if ((r = ssh_agent_sign(auth_sock, pubkey, 2043 signature, slenp, data, dlen, alg, 2044 ssh->compat)) != 0) { 2045 fatal("%s: agent sign failed: %s", 2046 __func__, ssh_err(r)); 2047 } 2048 } 2049 } 2050 return 0; 2051 } 2052 2053 /* SSH2 key exchange */ 2054 static void 2055 do_ssh2_kex(struct ssh *ssh) 2056 { 2057 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER }; 2058 struct kex *kex; 2059 int r; 2060 2061 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 2062 options.kex_algorithms); 2063 myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal( 2064 options.ciphers); 2065 myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal( 2066 options.ciphers); 2067 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 2068 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 2069 2070 if (options.compression == COMP_NONE) { 2071 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2072 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; 2073 } 2074 2075 if (options.rekey_limit || options.rekey_interval) 2076 ssh_packet_set_rekey_limits(ssh, options.rekey_limit, 2077 options.rekey_interval); 2078 2079 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal( 2080 list_hostkey_types()); 2081 2082 /* start key exchange */ 2083 if ((r = kex_setup(ssh, myproposal)) != 0) 2084 fatal("kex_setup: %s", ssh_err(r)); 2085 kex = ssh->kex; 2086 #ifdef WITH_OPENSSL 2087 kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server; 2088 kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server; 2089 kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server; 2090 kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server; 2091 kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server; 2092 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 2093 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 2094 kex->kex[KEX_ECDH_SHA2] = kex_gen_server; 2095 #endif 2096 kex->kex[KEX_C25519_SHA256] = kex_gen_server; 2097 kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_server; 2098 kex->load_host_public_key=&get_hostkey_public_by_type; 2099 kex->load_host_private_key=&get_hostkey_private_by_type; 2100 kex->host_key_index=&get_hostkey_index; 2101 kex->sign = sshd_hostkey_sign; 2102 2103 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &kex->done); 2104 2105 session_id2 = kex->session_id; 2106 session_id2_len = kex->session_id_len; 2107 2108 #ifdef DEBUG_KEXDH 2109 /* send 1st encrypted/maced/compressed message */ 2110 packet_start(SSH2_MSG_IGNORE); 2111 packet_put_cstring("markus"); 2112 packet_send(); 2113 packet_write_wait(); 2114 #endif 2115 debug("KEX done"); 2116 } 2117 2118 /* server specific fatal cleanup */ 2119 void 2120 cleanup_exit(int i) 2121 { 2122 if (the_active_state != NULL && the_authctxt != NULL) { 2123 do_cleanup(the_active_state, the_authctxt); 2124 if (use_privsep && privsep_is_preauth && 2125 pmonitor != NULL && pmonitor->m_pid > 1) { 2126 debug("Killing privsep child %d", pmonitor->m_pid); 2127 if (kill(pmonitor->m_pid, SIGKILL) != 0 && 2128 errno != ESRCH) 2129 error("%s: kill(%d): %s", __func__, 2130 pmonitor->m_pid, strerror(errno)); 2131 } 2132 } 2133 _exit(i); 2134 } 2135