1 /* $OpenBSD: sshd.c,v 1.516 2018/09/21 12:23:17 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * 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 int test_flag = 0; 137 138 /* Flag indicating that the daemon is being started from inetd. */ 139 int inetd_flag = 0; 140 141 /* Flag indicating that sshd should not detach and become a daemon. */ 142 int no_daemon_flag = 0; 143 144 /* debug goes to stderr unless inetd_flag is set */ 145 int log_stderr = 0; 146 147 /* Saved arguments to main(). */ 148 char **saved_argv; 149 150 /* re-exec */ 151 int rexeced_flag = 0; 152 int rexec_flag = 1; 153 int rexec_argc = 0; 154 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 int listen_socks[MAX_LISTEN_SOCKS]; 162 int num_listen_socks = 0; 163 164 /* 165 * the client's version string, passed by sshd2 in compat mode. if != NULL, 166 * sshd will skip the version-number exchange 167 */ 168 char *client_version_string = NULL; 169 char *server_version_string = NULL; 170 171 /* Daemon's agent connection */ 172 int auth_sock = -1; 173 int have_agent = 0; 174 175 /* 176 * Any really sensitive data in the application is contained in this 177 * structure. The idea is that this structure could be locked into memory so 178 * that the pages do not get written into swap. However, there are some 179 * problems. The private key contains BIGNUMs, and we do not (in principle) 180 * have access to the internals of them, and locking just the structure is 181 * not very useful. Currently, memory locking is not implemented. 182 */ 183 struct { 184 struct sshkey **host_keys; /* all private host keys */ 185 struct sshkey **host_pubkeys; /* all public host keys */ 186 struct sshkey **host_certificates; /* all public host certificates */ 187 int have_ssh2_key; 188 } sensitive_data; 189 190 /* This is set to true when a signal is received. */ 191 static volatile sig_atomic_t received_sighup = 0; 192 static volatile sig_atomic_t received_sigterm = 0; 193 194 /* session identifier, used by RSA-auth */ 195 u_char session_id[16]; 196 197 /* same for ssh2 */ 198 u_char *session_id2 = NULL; 199 u_int session_id2_len = 0; 200 201 /* record remote hostname or ip */ 202 u_int utmp_len = HOST_NAME_MAX+1; 203 204 /* options.max_startup sized array of fd ints */ 205 int *startup_pipes = NULL; 206 int startup_pipe; /* in child */ 207 208 /* variables used for privilege separation */ 209 int use_privsep = -1; 210 struct monitor *pmonitor = NULL; 211 int privsep_is_preauth = 1; 212 213 /* global authentication context */ 214 Authctxt *the_authctxt = NULL; 215 216 /* global key/cert auth options. XXX move to permanent ssh->authctxt? */ 217 struct sshauthopt *auth_opts = NULL; 218 219 /* sshd_config buffer */ 220 struct sshbuf *cfg; 221 222 /* message to be displayed after login */ 223 struct sshbuf *loginmsg; 224 225 /* Prototypes for various functions defined later in this file. */ 226 void destroy_sensitive_data(void); 227 void demote_sensitive_data(void); 228 static void do_ssh2_kex(void); 229 230 /* 231 * Close all listening sockets 232 */ 233 static void 234 close_listen_socks(void) 235 { 236 int i; 237 238 for (i = 0; i < num_listen_socks; i++) 239 close(listen_socks[i]); 240 num_listen_socks = -1; 241 } 242 243 static void 244 close_startup_pipes(void) 245 { 246 int i; 247 248 if (startup_pipes) 249 for (i = 0; i < options.max_startups; i++) 250 if (startup_pipes[i] != -1) 251 close(startup_pipes[i]); 252 } 253 254 /* 255 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; 256 * the effect is to reread the configuration file (and to regenerate 257 * the server key). 258 */ 259 260 /*ARGSUSED*/ 261 static void 262 sighup_handler(int sig) 263 { 264 int save_errno = errno; 265 266 received_sighup = 1; 267 errno = save_errno; 268 } 269 270 /* 271 * Called from the main program after receiving SIGHUP. 272 * Restarts the server. 273 */ 274 static void 275 sighup_restart(void) 276 { 277 logit("Received SIGHUP; restarting."); 278 if (options.pid_file != NULL) 279 unlink(options.pid_file); 280 close_listen_socks(); 281 close_startup_pipes(); 282 alarm(0); /* alarm timer persists across exec */ 283 signal(SIGHUP, SIG_IGN); /* will be restored after exec */ 284 execv(saved_argv[0], saved_argv); 285 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], 286 strerror(errno)); 287 exit(1); 288 } 289 290 /* 291 * Generic signal handler for terminating signals in the master daemon. 292 */ 293 /*ARGSUSED*/ 294 static void 295 sigterm_handler(int sig) 296 { 297 received_sigterm = sig; 298 } 299 300 /* 301 * SIGCHLD handler. This is called whenever a child dies. This will then 302 * reap any zombies left by exited children. 303 */ 304 /*ARGSUSED*/ 305 static void 306 main_sigchld_handler(int sig) 307 { 308 int save_errno = errno; 309 pid_t pid; 310 int status; 311 312 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 313 (pid < 0 && errno == EINTR)) 314 ; 315 errno = save_errno; 316 } 317 318 /* 319 * Signal handler for the alarm after the login grace period has expired. 320 */ 321 /*ARGSUSED*/ 322 static void 323 grace_alarm_handler(int sig) 324 { 325 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) 326 kill(pmonitor->m_pid, SIGALRM); 327 328 /* 329 * Try to kill any processes that we have spawned, E.g. authorized 330 * keys command helpers. 331 */ 332 if (getpgid(0) == getpid()) { 333 signal(SIGTERM, SIG_IGN); 334 kill(0, SIGTERM); 335 } 336 337 /* Log error and exit. */ 338 sigdie("Timeout before authentication for %s port %d", 339 ssh_remote_ipaddr(active_state), ssh_remote_port(active_state)); 340 } 341 342 static void 343 sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out) 344 { 345 u_int i; 346 int remote_major, remote_minor; 347 char *s; 348 char buf[256]; /* Must not be larger than remote_version. */ 349 char remote_version[256]; /* Must be at least as big as buf. */ 350 351 xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s\r\n", 352 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION, 353 *options.version_addendum == '\0' ? "" : " ", 354 options.version_addendum); 355 356 /* Send our protocol version identification. */ 357 if (atomicio(vwrite, sock_out, server_version_string, 358 strlen(server_version_string)) 359 != strlen(server_version_string)) { 360 logit("Could not write ident string to %s port %d", 361 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 362 cleanup_exit(255); 363 } 364 365 /* Read other sides version identification. */ 366 memset(buf, 0, sizeof(buf)); 367 for (i = 0; i < sizeof(buf) - 1; i++) { 368 if (atomicio(read, sock_in, &buf[i], 1) != 1) { 369 logit("Did not receive identification string " 370 "from %s port %d", 371 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 372 cleanup_exit(255); 373 } 374 if (buf[i] == '\r') { 375 buf[i] = 0; 376 /* Kludge for F-Secure Macintosh < 1.0.2 */ 377 if (i == 12 && 378 strncmp(buf, "SSH-1.5-W1.0", 12) == 0) 379 break; 380 continue; 381 } 382 if (buf[i] == '\n') { 383 buf[i] = 0; 384 break; 385 } 386 } 387 buf[sizeof(buf) - 1] = 0; 388 client_version_string = xstrdup(buf); 389 390 /* 391 * Check that the versions match. In future this might accept 392 * several versions and set appropriate flags to handle them. 393 */ 394 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", 395 &remote_major, &remote_minor, remote_version) != 3) { 396 s = "Protocol mismatch.\n"; 397 (void) atomicio(vwrite, sock_out, s, strlen(s)); 398 logit("Bad protocol version identification '%.100s' " 399 "from %s port %d", client_version_string, 400 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 401 close(sock_in); 402 close(sock_out); 403 cleanup_exit(255); 404 } 405 debug("Client protocol version %d.%d; client software version %.100s", 406 remote_major, remote_minor, remote_version); 407 408 ssh->compat = compat_datafellows(remote_version); 409 410 if ((ssh->compat & SSH_BUG_PROBE) != 0) { 411 logit("probed from %s port %d with %s. Don't panic.", 412 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 413 client_version_string); 414 cleanup_exit(255); 415 } 416 if ((ssh->compat & SSH_BUG_SCANNER) != 0) { 417 logit("scanned from %s port %d with %s. Don't panic.", 418 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 419 client_version_string); 420 cleanup_exit(255); 421 } 422 if ((ssh->compat & SSH_BUG_RSASIGMD5) != 0) { 423 logit("Client version \"%.100s\" uses unsafe RSA signature " 424 "scheme; disabling use of RSA keys", remote_version); 425 } 426 427 chop(server_version_string); 428 debug("Local version string %.200s", server_version_string); 429 430 if (remote_major != 2 && 431 !(remote_major == 1 && remote_minor == 99)) { 432 s = "Protocol major versions differ.\n"; 433 (void) atomicio(vwrite, sock_out, s, strlen(s)); 434 close(sock_in); 435 close(sock_out); 436 logit("Protocol major versions differ for %s port %d: " 437 "%.200s vs. %.200s", 438 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 439 server_version_string, client_version_string); 440 cleanup_exit(255); 441 } 442 } 443 444 /* Destroy the host and server keys. They will no longer be needed. */ 445 void 446 destroy_sensitive_data(void) 447 { 448 u_int i; 449 450 for (i = 0; i < options.num_host_key_files; i++) { 451 if (sensitive_data.host_keys[i]) { 452 sshkey_free(sensitive_data.host_keys[i]); 453 sensitive_data.host_keys[i] = NULL; 454 } 455 if (sensitive_data.host_certificates[i]) { 456 sshkey_free(sensitive_data.host_certificates[i]); 457 sensitive_data.host_certificates[i] = NULL; 458 } 459 } 460 } 461 462 /* Demote private to public keys for network child */ 463 void 464 demote_sensitive_data(void) 465 { 466 struct sshkey *tmp; 467 u_int i; 468 int r; 469 470 for (i = 0; i < options.num_host_key_files; i++) { 471 if (sensitive_data.host_keys[i]) { 472 if ((r = sshkey_from_private( 473 sensitive_data.host_keys[i], &tmp)) != 0) 474 fatal("could not demote host %s key: %s", 475 sshkey_type(sensitive_data.host_keys[i]), 476 ssh_err(r)); 477 sshkey_free(sensitive_data.host_keys[i]); 478 sensitive_data.host_keys[i] = tmp; 479 } 480 /* Certs do not need demotion */ 481 } 482 } 483 484 static void 485 privsep_preauth_child(void) 486 { 487 gid_t gidset[1]; 488 struct passwd *pw; 489 490 /* Enable challenge-response authentication for privilege separation */ 491 privsep_challenge_enable(); 492 493 #ifdef GSSAPI 494 /* Cache supported mechanism OIDs for later use */ 495 ssh_gssapi_prepare_supported_oids(); 496 #endif 497 498 /* Demote the private keys to public keys. */ 499 demote_sensitive_data(); 500 501 /* Demote the child */ 502 if (getuid() == 0 || geteuid() == 0) { 503 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) 504 fatal("Privilege separation user %s does not exist", 505 SSH_PRIVSEP_USER); 506 pw = pwcopy(pw); /* Ensure mutable */ 507 endpwent(); 508 freezero(pw->pw_passwd, strlen(pw->pw_passwd)); 509 510 /* Change our root directory */ 511 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) 512 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, 513 strerror(errno)); 514 if (chdir("/") == -1) 515 fatal("chdir(\"/\"): %s", strerror(errno)); 516 517 /* 518 * Drop our privileges 519 * NB. Can't use setusercontext() after chroot. 520 */ 521 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, 522 (u_int)pw->pw_gid); 523 gidset[0] = pw->pw_gid; 524 if (setgroups(1, gidset) < 0) 525 fatal("setgroups: %.100s", strerror(errno)); 526 permanently_set_uid(pw); 527 } 528 } 529 530 static int 531 privsep_preauth(Authctxt *authctxt) 532 { 533 int status, r; 534 pid_t pid; 535 struct ssh_sandbox *box = NULL; 536 537 /* Set up unprivileged child process to deal with network data */ 538 pmonitor = monitor_init(); 539 /* Store a pointer to the kex for later rekeying */ 540 pmonitor->m_pkex = &active_state->kex; 541 542 if (use_privsep == PRIVSEP_ON) 543 box = ssh_sandbox_init(); 544 pid = fork(); 545 if (pid == -1) { 546 fatal("fork of unprivileged child failed"); 547 } else if (pid != 0) { 548 debug2("Network child is on pid %ld", (long)pid); 549 550 pmonitor->m_pid = pid; 551 if (have_agent) { 552 r = ssh_get_authentication_socket(&auth_sock); 553 if (r != 0) { 554 error("Could not get agent socket: %s", 555 ssh_err(r)); 556 have_agent = 0; 557 } 558 } 559 if (box != NULL) 560 ssh_sandbox_parent_preauth(box, pid); 561 monitor_child_preauth(authctxt, pmonitor); 562 563 /* Wait for the child's exit status */ 564 while (waitpid(pid, &status, 0) < 0) { 565 if (errno == EINTR) 566 continue; 567 pmonitor->m_pid = -1; 568 fatal("%s: waitpid: %s", __func__, strerror(errno)); 569 } 570 privsep_is_preauth = 0; 571 pmonitor->m_pid = -1; 572 if (WIFEXITED(status)) { 573 if (WEXITSTATUS(status) != 0) 574 fatal("%s: preauth child exited with status %d", 575 __func__, WEXITSTATUS(status)); 576 } else if (WIFSIGNALED(status)) 577 fatal("%s: preauth child terminated by signal %d", 578 __func__, WTERMSIG(status)); 579 if (box != NULL) 580 ssh_sandbox_parent_finish(box); 581 return 1; 582 } else { 583 /* child */ 584 close(pmonitor->m_sendfd); 585 close(pmonitor->m_log_recvfd); 586 587 /* Arrange for logging to be sent to the monitor */ 588 set_log_handler(mm_log_handler, pmonitor); 589 590 privsep_preauth_child(); 591 setproctitle("%s", "[net]"); 592 if (box != NULL) 593 ssh_sandbox_child(box); 594 595 return 0; 596 } 597 } 598 599 static void 600 privsep_postauth(Authctxt *authctxt) 601 { 602 if (authctxt->pw->pw_uid == 0) { 603 /* File descriptor passing is broken or root login */ 604 use_privsep = 0; 605 goto skip; 606 } 607 608 /* New socket pair */ 609 monitor_reinit(pmonitor); 610 611 pmonitor->m_pid = fork(); 612 if (pmonitor->m_pid == -1) 613 fatal("fork of unprivileged child failed"); 614 else if (pmonitor->m_pid != 0) { 615 verbose("User child is on pid %ld", (long)pmonitor->m_pid); 616 sshbuf_reset(loginmsg); 617 monitor_clear_keystate(pmonitor); 618 monitor_child_postauth(pmonitor); 619 620 /* NEVERREACHED */ 621 exit(0); 622 } 623 624 /* child */ 625 626 close(pmonitor->m_sendfd); 627 pmonitor->m_sendfd = -1; 628 629 /* Demote the private keys to public keys. */ 630 demote_sensitive_data(); 631 632 /* Drop privileges */ 633 do_setusercontext(authctxt->pw); 634 635 skip: 636 /* It is safe now to apply the key state */ 637 monitor_apply_keystate(pmonitor); 638 639 /* 640 * Tell the packet layer that authentication was successful, since 641 * this information is not part of the key state. 642 */ 643 packet_set_authenticated(); 644 } 645 646 static void 647 append_hostkey_type(struct sshbuf *b, const char *s) 648 { 649 int r; 650 651 if (match_pattern_list(s, options.hostkeyalgorithms, 0) != 1) { 652 debug3("%s: %s key not permitted by HostkeyAlgorithms", 653 __func__, s); 654 return; 655 } 656 if ((r = sshbuf_putf(b, "%s%s", sshbuf_len(b) > 0 ? "," : "", s)) != 0) 657 fatal("%s: sshbuf_putf: %s", __func__, ssh_err(r)); 658 } 659 660 static char * 661 list_hostkey_types(void) 662 { 663 struct sshbuf *b; 664 struct sshkey *key; 665 char *ret; 666 u_int i; 667 668 if ((b = sshbuf_new()) == NULL) 669 fatal("%s: sshbuf_new failed", __func__); 670 for (i = 0; i < options.num_host_key_files; i++) { 671 key = sensitive_data.host_keys[i]; 672 if (key == NULL) 673 key = sensitive_data.host_pubkeys[i]; 674 if (key == NULL) 675 continue; 676 switch (key->type) { 677 case KEY_RSA: 678 /* for RSA we also support SHA2 signatures */ 679 append_hostkey_type(b, "rsa-sha2-512"); 680 append_hostkey_type(b, "rsa-sha2-256"); 681 /* FALLTHROUGH */ 682 case KEY_DSA: 683 case KEY_ECDSA: 684 case KEY_ED25519: 685 case KEY_XMSS: 686 append_hostkey_type(b, sshkey_ssh_name(key)); 687 break; 688 } 689 /* If the private key has a cert peer, then list that too */ 690 key = sensitive_data.host_certificates[i]; 691 if (key == NULL) 692 continue; 693 switch (key->type) { 694 case KEY_RSA_CERT: 695 /* for RSA we also support SHA2 signatures */ 696 append_hostkey_type(b, 697 "rsa-sha2-512-cert-v01@openssh.com"); 698 append_hostkey_type(b, 699 "rsa-sha2-256-cert-v01@openssh.com"); 700 /* FALLTHROUGH */ 701 case KEY_DSA_CERT: 702 case KEY_ECDSA_CERT: 703 case KEY_ED25519_CERT: 704 case KEY_XMSS_CERT: 705 append_hostkey_type(b, sshkey_ssh_name(key)); 706 break; 707 } 708 } 709 if ((ret = sshbuf_dup_string(b)) == NULL) 710 fatal("%s: sshbuf_dup_string failed", __func__); 711 sshbuf_free(b); 712 debug("%s: %s", __func__, ret); 713 return ret; 714 } 715 716 static struct sshkey * 717 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh) 718 { 719 u_int i; 720 struct sshkey *key; 721 722 for (i = 0; i < options.num_host_key_files; i++) { 723 switch (type) { 724 case KEY_RSA_CERT: 725 case KEY_DSA_CERT: 726 case KEY_ECDSA_CERT: 727 case KEY_ED25519_CERT: 728 case KEY_XMSS_CERT: 729 key = sensitive_data.host_certificates[i]; 730 break; 731 default: 732 key = sensitive_data.host_keys[i]; 733 if (key == NULL && !need_private) 734 key = sensitive_data.host_pubkeys[i]; 735 break; 736 } 737 if (key != NULL && key->type == type && 738 (key->type != KEY_ECDSA || key->ecdsa_nid == nid)) 739 return need_private ? 740 sensitive_data.host_keys[i] : key; 741 } 742 return NULL; 743 } 744 745 struct sshkey * 746 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh) 747 { 748 return get_hostkey_by_type(type, nid, 0, ssh); 749 } 750 751 struct sshkey * 752 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh) 753 { 754 return get_hostkey_by_type(type, nid, 1, ssh); 755 } 756 757 struct sshkey * 758 get_hostkey_by_index(int ind) 759 { 760 if (ind < 0 || (u_int)ind >= options.num_host_key_files) 761 return (NULL); 762 return (sensitive_data.host_keys[ind]); 763 } 764 765 struct sshkey * 766 get_hostkey_public_by_index(int ind, struct ssh *ssh) 767 { 768 if (ind < 0 || (u_int)ind >= options.num_host_key_files) 769 return (NULL); 770 return (sensitive_data.host_pubkeys[ind]); 771 } 772 773 int 774 get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh) 775 { 776 u_int i; 777 778 for (i = 0; i < options.num_host_key_files; i++) { 779 if (sshkey_is_cert(key)) { 780 if (key == sensitive_data.host_certificates[i] || 781 (compare && sensitive_data.host_certificates[i] && 782 sshkey_equal(key, 783 sensitive_data.host_certificates[i]))) 784 return (i); 785 } else { 786 if (key == sensitive_data.host_keys[i] || 787 (compare && sensitive_data.host_keys[i] && 788 sshkey_equal(key, sensitive_data.host_keys[i]))) 789 return (i); 790 if (key == sensitive_data.host_pubkeys[i] || 791 (compare && sensitive_data.host_pubkeys[i] && 792 sshkey_equal(key, sensitive_data.host_pubkeys[i]))) 793 return (i); 794 } 795 } 796 return (-1); 797 } 798 799 /* Inform the client of all hostkeys */ 800 static void 801 notify_hostkeys(struct ssh *ssh) 802 { 803 struct sshbuf *buf; 804 struct sshkey *key; 805 u_int i, nkeys; 806 int r; 807 char *fp; 808 809 /* Some clients cannot cope with the hostkeys message, skip those. */ 810 if (datafellows & SSH_BUG_HOSTKEYS) 811 return; 812 813 if ((buf = sshbuf_new()) == NULL) 814 fatal("%s: sshbuf_new", __func__); 815 for (i = nkeys = 0; i < options.num_host_key_files; i++) { 816 key = get_hostkey_public_by_index(i, ssh); 817 if (key == NULL || key->type == KEY_UNSPEC || 818 sshkey_is_cert(key)) 819 continue; 820 fp = sshkey_fingerprint(key, options.fingerprint_hash, 821 SSH_FP_DEFAULT); 822 debug3("%s: key %d: %s %s", __func__, i, 823 sshkey_ssh_name(key), fp); 824 free(fp); 825 if (nkeys == 0) { 826 packet_start(SSH2_MSG_GLOBAL_REQUEST); 827 packet_put_cstring("hostkeys-00@openssh.com"); 828 packet_put_char(0); /* want-reply */ 829 } 830 sshbuf_reset(buf); 831 if ((r = sshkey_putb(key, buf)) != 0) 832 fatal("%s: couldn't put hostkey %d: %s", 833 __func__, i, ssh_err(r)); 834 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf)); 835 nkeys++; 836 } 837 debug3("%s: sent %u hostkeys", __func__, nkeys); 838 if (nkeys == 0) 839 fatal("%s: no hostkeys", __func__); 840 packet_send(); 841 sshbuf_free(buf); 842 } 843 844 /* 845 * returns 1 if connection should be dropped, 0 otherwise. 846 * dropping starts at connection #max_startups_begin with a probability 847 * of (max_startups_rate/100). the probability increases linearly until 848 * all connections are dropped for startups > max_startups 849 */ 850 static int 851 drop_connection(int startups) 852 { 853 int p, r; 854 855 if (startups < options.max_startups_begin) 856 return 0; 857 if (startups >= options.max_startups) 858 return 1; 859 if (options.max_startups_rate == 100) 860 return 1; 861 862 p = 100 - options.max_startups_rate; 863 p *= startups - options.max_startups_begin; 864 p /= options.max_startups - options.max_startups_begin; 865 p += options.max_startups_rate; 866 r = arc4random_uniform(100); 867 868 debug("drop_connection: p %d, r %d", p, r); 869 return (r < p) ? 1 : 0; 870 } 871 872 static void 873 usage(void) 874 { 875 fprintf(stderr, "%s, %s\n", 876 SSH_VERSION, 877 #ifdef WITH_OPENSSL 878 SSLeay_version(SSLEAY_VERSION) 879 #else 880 "without OpenSSL" 881 #endif 882 ); 883 fprintf(stderr, 884 "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n" 885 " [-E log_file] [-f config_file] [-g login_grace_time]\n" 886 " [-h host_key_file] [-o option] [-p port] [-u len]\n" 887 ); 888 exit(1); 889 } 890 891 static void 892 send_rexec_state(int fd, struct sshbuf *conf) 893 { 894 struct sshbuf *m; 895 int r; 896 897 debug3("%s: entering fd = %d config len %zu", __func__, fd, 898 sshbuf_len(conf)); 899 900 /* 901 * Protocol from reexec master to child: 902 * string configuration 903 */ 904 if ((m = sshbuf_new()) == NULL) 905 fatal("%s: sshbuf_new failed", __func__); 906 if ((r = sshbuf_put_stringb(m, conf)) != 0) 907 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 908 if (ssh_msg_send(fd, 0, m) == -1) 909 fatal("%s: ssh_msg_send failed", __func__); 910 911 sshbuf_free(m); 912 913 debug3("%s: done", __func__); 914 } 915 916 static void 917 recv_rexec_state(int fd, struct sshbuf *conf) 918 { 919 struct sshbuf *m; 920 u_char *cp, ver; 921 size_t len; 922 int r; 923 924 debug3("%s: entering fd = %d", __func__, fd); 925 926 if ((m = sshbuf_new()) == NULL) 927 fatal("%s: sshbuf_new failed", __func__); 928 if (ssh_msg_recv(fd, m) == -1) 929 fatal("%s: ssh_msg_recv failed", __func__); 930 if ((r = sshbuf_get_u8(m, &ver)) != 0) 931 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 932 if (ver != 0) 933 fatal("%s: rexec version mismatch", __func__); 934 if ((r = sshbuf_get_string(m, &cp, &len)) != 0) 935 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 936 if (conf != NULL && (r = sshbuf_put(conf, cp, len))) 937 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 938 939 free(cp); 940 sshbuf_free(m); 941 942 debug3("%s: done", __func__); 943 } 944 945 /* Accept a connection from inetd */ 946 static void 947 server_accept_inetd(int *sock_in, int *sock_out) 948 { 949 int fd; 950 951 startup_pipe = -1; 952 if (rexeced_flag) { 953 close(REEXEC_CONFIG_PASS_FD); 954 *sock_in = *sock_out = dup(STDIN_FILENO); 955 if (!debug_flag) { 956 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); 957 close(REEXEC_STARTUP_PIPE_FD); 958 } 959 } else { 960 *sock_in = dup(STDIN_FILENO); 961 *sock_out = dup(STDOUT_FILENO); 962 } 963 /* 964 * We intentionally do not close the descriptors 0, 1, and 2 965 * as our code for setting the descriptors won't work if 966 * ttyfd happens to be one of those. 967 */ 968 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 969 dup2(fd, STDIN_FILENO); 970 dup2(fd, STDOUT_FILENO); 971 if (!log_stderr) 972 dup2(fd, STDERR_FILENO); 973 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO)) 974 close(fd); 975 } 976 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); 977 } 978 979 /* 980 * Listen for TCP connections 981 */ 982 static void 983 listen_on_addrs(struct listenaddr *la) 984 { 985 int ret, listen_sock; 986 struct addrinfo *ai; 987 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 988 989 for (ai = la->addrs; ai; ai = ai->ai_next) { 990 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 991 continue; 992 if (num_listen_socks >= MAX_LISTEN_SOCKS) 993 fatal("Too many listen sockets. " 994 "Enlarge MAX_LISTEN_SOCKS"); 995 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, 996 ntop, sizeof(ntop), strport, sizeof(strport), 997 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { 998 error("getnameinfo failed: %.100s", 999 ssh_gai_strerror(ret)); 1000 continue; 1001 } 1002 /* Create socket for listening. */ 1003 listen_sock = socket(ai->ai_family, ai->ai_socktype, 1004 ai->ai_protocol); 1005 if (listen_sock < 0) { 1006 /* kernel may not support ipv6 */ 1007 verbose("socket: %.100s", strerror(errno)); 1008 continue; 1009 } 1010 if (set_nonblock(listen_sock) == -1) { 1011 close(listen_sock); 1012 continue; 1013 } 1014 if (fcntl(listen_sock, F_SETFD, FD_CLOEXEC) == -1) { 1015 verbose("socket: CLOEXEC: %s", strerror(errno)); 1016 close(listen_sock); 1017 continue; 1018 } 1019 /* Socket options */ 1020 set_reuseaddr(listen_sock); 1021 if (la->rdomain != NULL && 1022 set_rdomain(listen_sock, la->rdomain) == -1) { 1023 close(listen_sock); 1024 continue; 1025 } 1026 1027 debug("Bind to port %s on %s.", strport, ntop); 1028 1029 /* Bind the socket to the desired port. */ 1030 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1031 error("Bind to port %s on %s failed: %.200s.", 1032 strport, ntop, strerror(errno)); 1033 close(listen_sock); 1034 continue; 1035 } 1036 listen_socks[num_listen_socks] = listen_sock; 1037 num_listen_socks++; 1038 1039 /* Start listening on the port. */ 1040 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) 1041 fatal("listen on [%s]:%s: %.100s", 1042 ntop, strport, strerror(errno)); 1043 logit("Server listening on %s port %s%s%s.", 1044 ntop, strport, 1045 la->rdomain == NULL ? "" : " rdomain ", 1046 la->rdomain == NULL ? "" : la->rdomain); 1047 } 1048 } 1049 1050 static void 1051 server_listen(void) 1052 { 1053 u_int i; 1054 1055 for (i = 0; i < options.num_listen_addrs; i++) { 1056 listen_on_addrs(&options.listen_addrs[i]); 1057 freeaddrinfo(options.listen_addrs[i].addrs); 1058 free(options.listen_addrs[i].rdomain); 1059 memset(&options.listen_addrs[i], 0, 1060 sizeof(options.listen_addrs[i])); 1061 } 1062 free(options.listen_addrs); 1063 options.listen_addrs = NULL; 1064 options.num_listen_addrs = 0; 1065 1066 if (!num_listen_socks) 1067 fatal("Cannot bind any address."); 1068 } 1069 1070 /* 1071 * The main TCP accept loop. Note that, for the non-debug case, returns 1072 * from this function are in a forked subprocess. 1073 */ 1074 static void 1075 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) 1076 { 1077 fd_set *fdset; 1078 int i, j, ret, maxfd; 1079 int startups = 0; 1080 int startup_p[2] = { -1 , -1 }; 1081 struct sockaddr_storage from; 1082 socklen_t fromlen; 1083 pid_t pid; 1084 1085 /* setup fd set for accept */ 1086 fdset = NULL; 1087 maxfd = 0; 1088 for (i = 0; i < num_listen_socks; i++) 1089 if (listen_socks[i] > maxfd) 1090 maxfd = listen_socks[i]; 1091 /* pipes connected to unauthenticated childs */ 1092 startup_pipes = xcalloc(options.max_startups, sizeof(int)); 1093 for (i = 0; i < options.max_startups; i++) 1094 startup_pipes[i] = -1; 1095 1096 /* 1097 * Stay listening for connections until the system crashes or 1098 * the daemon is killed with a signal. 1099 */ 1100 for (;;) { 1101 if (received_sighup) 1102 sighup_restart(); 1103 free(fdset); 1104 fdset = xcalloc(howmany(maxfd + 1, NFDBITS), 1105 sizeof(fd_mask)); 1106 1107 for (i = 0; i < num_listen_socks; i++) 1108 FD_SET(listen_socks[i], fdset); 1109 for (i = 0; i < options.max_startups; i++) 1110 if (startup_pipes[i] != -1) 1111 FD_SET(startup_pipes[i], fdset); 1112 1113 /* Wait in select until there is a connection. */ 1114 ret = select(maxfd+1, fdset, NULL, NULL, NULL); 1115 if (ret < 0 && errno != EINTR) 1116 error("select: %.100s", strerror(errno)); 1117 if (received_sigterm) { 1118 logit("Received signal %d; terminating.", 1119 (int) received_sigterm); 1120 close_listen_socks(); 1121 if (options.pid_file != NULL) 1122 unlink(options.pid_file); 1123 exit(received_sigterm == SIGTERM ? 0 : 255); 1124 } 1125 if (ret < 0) 1126 continue; 1127 1128 for (i = 0; i < options.max_startups; i++) 1129 if (startup_pipes[i] != -1 && 1130 FD_ISSET(startup_pipes[i], fdset)) { 1131 /* 1132 * the read end of the pipe is ready 1133 * if the child has closed the pipe 1134 * after successful authentication 1135 * or if the child has died 1136 */ 1137 close(startup_pipes[i]); 1138 startup_pipes[i] = -1; 1139 startups--; 1140 } 1141 for (i = 0; i < num_listen_socks; i++) { 1142 if (!FD_ISSET(listen_socks[i], fdset)) 1143 continue; 1144 fromlen = sizeof(from); 1145 *newsock = accept(listen_socks[i], 1146 (struct sockaddr *)&from, &fromlen); 1147 if (*newsock < 0) { 1148 if (errno != EINTR && errno != EWOULDBLOCK && 1149 errno != ECONNABORTED) 1150 error("accept: %.100s", 1151 strerror(errno)); 1152 if (errno == EMFILE || errno == ENFILE) 1153 usleep(100 * 1000); 1154 continue; 1155 } 1156 if (unset_nonblock(*newsock) == -1) { 1157 close(*newsock); 1158 continue; 1159 } 1160 if (drop_connection(startups) == 1) { 1161 char *laddr = get_local_ipaddr(*newsock); 1162 char *raddr = get_peer_ipaddr(*newsock); 1163 1164 verbose("drop connection #%d from [%s]:%d " 1165 "on [%s]:%d past MaxStartups", startups, 1166 raddr, get_peer_port(*newsock), 1167 laddr, get_local_port(*newsock)); 1168 free(laddr); 1169 free(raddr); 1170 close(*newsock); 1171 continue; 1172 } 1173 if (pipe(startup_p) == -1) { 1174 close(*newsock); 1175 continue; 1176 } 1177 1178 if (rexec_flag && socketpair(AF_UNIX, 1179 SOCK_STREAM, 0, config_s) == -1) { 1180 error("reexec socketpair: %s", 1181 strerror(errno)); 1182 close(*newsock); 1183 close(startup_p[0]); 1184 close(startup_p[1]); 1185 continue; 1186 } 1187 1188 for (j = 0; j < options.max_startups; j++) 1189 if (startup_pipes[j] == -1) { 1190 startup_pipes[j] = startup_p[0]; 1191 if (maxfd < startup_p[0]) 1192 maxfd = startup_p[0]; 1193 startups++; 1194 break; 1195 } 1196 1197 /* 1198 * Got connection. Fork a child to handle it, unless 1199 * we are in debugging mode. 1200 */ 1201 if (debug_flag) { 1202 /* 1203 * In debugging mode. Close the listening 1204 * socket, and start processing the 1205 * connection without forking. 1206 */ 1207 debug("Server will not fork when running in debugging mode."); 1208 close_listen_socks(); 1209 *sock_in = *newsock; 1210 *sock_out = *newsock; 1211 close(startup_p[0]); 1212 close(startup_p[1]); 1213 startup_pipe = -1; 1214 pid = getpid(); 1215 if (rexec_flag) { 1216 send_rexec_state(config_s[0], cfg); 1217 close(config_s[0]); 1218 } 1219 break; 1220 } 1221 1222 /* 1223 * Normal production daemon. Fork, and have 1224 * the child process the connection. The 1225 * parent continues listening. 1226 */ 1227 if ((pid = fork()) == 0) { 1228 /* 1229 * Child. Close the listening and 1230 * max_startup sockets. Start using 1231 * the accepted socket. Reinitialize 1232 * logging (since our pid has changed). 1233 * We break out of the loop to handle 1234 * the connection. 1235 */ 1236 startup_pipe = startup_p[1]; 1237 close_startup_pipes(); 1238 close_listen_socks(); 1239 *sock_in = *newsock; 1240 *sock_out = *newsock; 1241 log_init(__progname, 1242 options.log_level, 1243 options.log_facility, 1244 log_stderr); 1245 if (rexec_flag) 1246 close(config_s[0]); 1247 break; 1248 } 1249 1250 /* Parent. Stay in the loop. */ 1251 if (pid < 0) 1252 error("fork: %.100s", strerror(errno)); 1253 else 1254 debug("Forked child %ld.", (long)pid); 1255 1256 close(startup_p[1]); 1257 1258 if (rexec_flag) { 1259 send_rexec_state(config_s[0], cfg); 1260 close(config_s[0]); 1261 close(config_s[1]); 1262 } 1263 close(*newsock); 1264 } 1265 1266 /* child process check (or debug mode) */ 1267 if (num_listen_socks < 0) 1268 break; 1269 } 1270 } 1271 1272 /* 1273 * If IP options are supported, make sure there are none (log and 1274 * return an error if any are found). Basically we are worried about 1275 * source routing; it can be used to pretend you are somebody 1276 * (ip-address) you are not. That itself may be "almost acceptable" 1277 * under certain circumstances, but rhosts authentication is useless 1278 * if source routing is accepted. Notice also that if we just dropped 1279 * source routing here, the other side could use IP spoofing to do 1280 * rest of the interaction and could still bypass security. So we 1281 * exit here if we detect any IP options. 1282 */ 1283 static void 1284 check_ip_options(struct ssh *ssh) 1285 { 1286 int sock_in = ssh_packet_get_connection_in(ssh); 1287 struct sockaddr_storage from; 1288 u_char opts[200]; 1289 socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from); 1290 char text[sizeof(opts) * 3 + 1]; 1291 1292 memset(&from, 0, sizeof(from)); 1293 if (getpeername(sock_in, (struct sockaddr *)&from, 1294 &fromlen) < 0) 1295 return; 1296 if (from.ss_family != AF_INET) 1297 return; 1298 /* XXX IPv6 options? */ 1299 1300 if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts, 1301 &option_size) >= 0 && option_size != 0) { 1302 text[0] = '\0'; 1303 for (i = 0; i < option_size; i++) 1304 snprintf(text + i*3, sizeof(text) - i*3, 1305 " %2.2x", opts[i]); 1306 fatal("Connection from %.100s port %d with IP opts: %.800s", 1307 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text); 1308 } 1309 return; 1310 } 1311 1312 /* Set the routing domain for this process */ 1313 static void 1314 set_process_rdomain(struct ssh *ssh, const char *name) 1315 { 1316 int rtable, ortable = getrtable(); 1317 const char *errstr; 1318 1319 if (name == NULL) 1320 return; /* default */ 1321 1322 if (strcmp(name, "%D") == 0) { 1323 /* "expands" to routing domain of connection */ 1324 if ((name = ssh_packet_rdomain_in(ssh)) == NULL) 1325 return; 1326 } 1327 1328 rtable = (int)strtonum(name, 0, 255, &errstr); 1329 if (errstr != NULL) /* Shouldn't happen */ 1330 fatal("Invalid routing domain \"%s\": %s", name, errstr); 1331 if (rtable != ortable && setrtable(rtable) != 0) 1332 fatal("Unable to set routing domain %d: %s", 1333 rtable, strerror(errno)); 1334 debug("%s: set routing domain %d (was %d)", __func__, rtable, ortable); 1335 } 1336 1337 static void 1338 accumulate_host_timing_secret(struct sshbuf *server_cfg, 1339 const struct sshkey *key) 1340 { 1341 static struct ssh_digest_ctx *ctx; 1342 u_char *hash; 1343 size_t len; 1344 struct sshbuf *buf; 1345 int r; 1346 1347 if (ctx == NULL && (ctx = ssh_digest_start(SSH_DIGEST_SHA512)) == NULL) 1348 fatal("%s: ssh_digest_start", __func__); 1349 if (key == NULL) { /* finalize */ 1350 /* add server config in case we are using agent for host keys */ 1351 if (ssh_digest_update(ctx, sshbuf_ptr(server_cfg), 1352 sshbuf_len(server_cfg)) != 0) 1353 fatal("%s: ssh_digest_update", __func__); 1354 len = ssh_digest_bytes(SSH_DIGEST_SHA512); 1355 hash = xmalloc(len); 1356 if (ssh_digest_final(ctx, hash, len) != 0) 1357 fatal("%s: ssh_digest_final", __func__); 1358 options.timing_secret = PEEK_U64(hash); 1359 freezero(hash, len); 1360 ssh_digest_free(ctx); 1361 ctx = NULL; 1362 return; 1363 } 1364 if ((buf = sshbuf_new()) == NULL) 1365 fatal("%s could not allocate buffer", __func__); 1366 if ((r = sshkey_private_serialize(key, buf)) != 0) 1367 fatal("sshkey_private_serialize: %s", ssh_err(r)); 1368 if (ssh_digest_update(ctx, sshbuf_ptr(buf), sshbuf_len(buf)) != 0) 1369 fatal("%s: ssh_digest_update", __func__); 1370 sshbuf_reset(buf); 1371 sshbuf_free(buf); 1372 } 1373 1374 /* 1375 * Main program for the daemon. 1376 */ 1377 int 1378 main(int ac, char **av) 1379 { 1380 struct ssh *ssh = NULL; 1381 extern char *optarg; 1382 extern int optind; 1383 int r, opt, on = 1, already_daemon, remote_port; 1384 int sock_in = -1, sock_out = -1, newsock = -1; 1385 const char *remote_ip, *rdomain; 1386 char *fp, *line, *laddr, *logfile = NULL; 1387 int config_s[2] = { -1 , -1 }; 1388 u_int i, j; 1389 u_int64_t ibytes, obytes; 1390 mode_t new_umask; 1391 struct sshkey *key; 1392 struct sshkey *pubkey; 1393 int keytype; 1394 Authctxt *authctxt; 1395 struct connection_info *connection_info = NULL; 1396 1397 ssh_malloc_init(); /* must be called before any mallocs */ 1398 /* Save argv. */ 1399 saved_argv = av; 1400 rexec_argc = ac; 1401 1402 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1403 sanitise_stdfd(); 1404 1405 /* Initialize configuration options to their default values. */ 1406 initialize_server_options(&options); 1407 1408 /* Parse command-line arguments. */ 1409 while ((opt = getopt(ac, av, 1410 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) { 1411 switch (opt) { 1412 case '4': 1413 options.address_family = AF_INET; 1414 break; 1415 case '6': 1416 options.address_family = AF_INET6; 1417 break; 1418 case 'f': 1419 config_file_name = optarg; 1420 break; 1421 case 'c': 1422 servconf_add_hostcert("[command-line]", 0, 1423 &options, optarg); 1424 break; 1425 case 'd': 1426 if (debug_flag == 0) { 1427 debug_flag = 1; 1428 options.log_level = SYSLOG_LEVEL_DEBUG1; 1429 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) 1430 options.log_level++; 1431 break; 1432 case 'D': 1433 no_daemon_flag = 1; 1434 break; 1435 case 'E': 1436 logfile = optarg; 1437 /* FALLTHROUGH */ 1438 case 'e': 1439 log_stderr = 1; 1440 break; 1441 case 'i': 1442 inetd_flag = 1; 1443 break; 1444 case 'r': 1445 rexec_flag = 0; 1446 break; 1447 case 'R': 1448 rexeced_flag = 1; 1449 inetd_flag = 1; 1450 break; 1451 case 'Q': 1452 /* ignored */ 1453 break; 1454 case 'q': 1455 options.log_level = SYSLOG_LEVEL_QUIET; 1456 break; 1457 case 'b': 1458 /* protocol 1, ignored */ 1459 break; 1460 case 'p': 1461 options.ports_from_cmdline = 1; 1462 if (options.num_ports >= MAX_PORTS) { 1463 fprintf(stderr, "too many ports.\n"); 1464 exit(1); 1465 } 1466 options.ports[options.num_ports++] = a2port(optarg); 1467 if (options.ports[options.num_ports-1] <= 0) { 1468 fprintf(stderr, "Bad port number.\n"); 1469 exit(1); 1470 } 1471 break; 1472 case 'g': 1473 if ((options.login_grace_time = convtime(optarg)) == -1) { 1474 fprintf(stderr, "Invalid login grace time.\n"); 1475 exit(1); 1476 } 1477 break; 1478 case 'k': 1479 /* protocol 1, ignored */ 1480 break; 1481 case 'h': 1482 servconf_add_hostkey("[command-line]", 0, 1483 &options, optarg); 1484 break; 1485 case 't': 1486 test_flag = 1; 1487 break; 1488 case 'T': 1489 test_flag = 2; 1490 break; 1491 case 'C': 1492 connection_info = get_connection_info(0, 0); 1493 if (parse_server_match_testspec(connection_info, 1494 optarg) == -1) 1495 exit(1); 1496 break; 1497 case 'u': 1498 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL); 1499 if (utmp_len > HOST_NAME_MAX+1) { 1500 fprintf(stderr, "Invalid utmp length.\n"); 1501 exit(1); 1502 } 1503 break; 1504 case 'o': 1505 line = xstrdup(optarg); 1506 if (process_server_config_line(&options, line, 1507 "command-line", 0, NULL, NULL) != 0) 1508 exit(1); 1509 free(line); 1510 break; 1511 case '?': 1512 default: 1513 usage(); 1514 break; 1515 } 1516 } 1517 if (rexeced_flag || inetd_flag) 1518 rexec_flag = 0; 1519 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) 1520 fatal("sshd re-exec requires execution with an absolute path"); 1521 if (rexeced_flag) 1522 closefrom(REEXEC_MIN_FREE_FD); 1523 else 1524 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); 1525 1526 #ifdef WITH_OPENSSL 1527 OpenSSL_add_all_algorithms(); 1528 #endif 1529 1530 /* If requested, redirect the logs to the specified logfile. */ 1531 if (logfile != NULL) 1532 log_redirect_stderr_to(logfile); 1533 /* 1534 * Force logging to stderr until we have loaded the private host 1535 * key (unless started from inetd) 1536 */ 1537 log_init(__progname, 1538 options.log_level == SYSLOG_LEVEL_NOT_SET ? 1539 SYSLOG_LEVEL_INFO : options.log_level, 1540 options.log_facility == SYSLOG_FACILITY_NOT_SET ? 1541 SYSLOG_FACILITY_AUTH : options.log_facility, 1542 log_stderr || !inetd_flag); 1543 1544 sensitive_data.have_ssh2_key = 0; 1545 1546 /* 1547 * If we're not doing an extended test do not silently ignore connection 1548 * test params. 1549 */ 1550 if (test_flag < 2 && connection_info != NULL) 1551 fatal("Config test connection parameter (-C) provided without " 1552 "test mode (-T)"); 1553 1554 /* Fetch our configuration */ 1555 if ((cfg = sshbuf_new()) == NULL) 1556 fatal("%s: sshbuf_new failed", __func__); 1557 if (rexeced_flag) 1558 recv_rexec_state(REEXEC_CONFIG_PASS_FD, cfg); 1559 else if (strcasecmp(config_file_name, "none") != 0) 1560 load_server_config(config_file_name, cfg); 1561 1562 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, 1563 cfg, NULL); 1564 1565 /* Fill in default values for those options not explicitly set. */ 1566 fill_default_server_options(&options); 1567 1568 /* challenge-response is implemented via keyboard interactive */ 1569 if (options.challenge_response_authentication) 1570 options.kbd_interactive_authentication = 1; 1571 1572 /* Check that options are sensible */ 1573 if (options.authorized_keys_command_user == NULL && 1574 (options.authorized_keys_command != NULL && 1575 strcasecmp(options.authorized_keys_command, "none") != 0)) 1576 fatal("AuthorizedKeysCommand set without " 1577 "AuthorizedKeysCommandUser"); 1578 if (options.authorized_principals_command_user == NULL && 1579 (options.authorized_principals_command != NULL && 1580 strcasecmp(options.authorized_principals_command, "none") != 0)) 1581 fatal("AuthorizedPrincipalsCommand set without " 1582 "AuthorizedPrincipalsCommandUser"); 1583 1584 /* 1585 * Check whether there is any path through configured auth methods. 1586 * Unfortunately it is not possible to verify this generally before 1587 * daemonisation in the presence of Match block, but this catches 1588 * and warns for trivial misconfigurations that could break login. 1589 */ 1590 if (options.num_auth_methods != 0) { 1591 for (i = 0; i < options.num_auth_methods; i++) { 1592 if (auth2_methods_valid(options.auth_methods[i], 1593 1) == 0) 1594 break; 1595 } 1596 if (i >= options.num_auth_methods) 1597 fatal("AuthenticationMethods cannot be satisfied by " 1598 "enabled authentication methods"); 1599 } 1600 1601 /* Check that there are no remaining arguments. */ 1602 if (optind < ac) { 1603 fprintf(stderr, "Extra argument %s.\n", av[optind]); 1604 exit(1); 1605 } 1606 1607 debug("sshd version %s, %s", SSH_VERSION, 1608 #ifdef WITH_OPENSSL 1609 SSLeay_version(SSLEAY_VERSION) 1610 #else 1611 "without OpenSSL" 1612 #endif 1613 ); 1614 1615 /* load host keys */ 1616 sensitive_data.host_keys = xcalloc(options.num_host_key_files, 1617 sizeof(struct sshkey *)); 1618 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files, 1619 sizeof(struct sshkey *)); 1620 1621 if (options.host_key_agent) { 1622 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME)) 1623 setenv(SSH_AUTHSOCKET_ENV_NAME, 1624 options.host_key_agent, 1); 1625 if ((r = ssh_get_authentication_socket(NULL)) == 0) 1626 have_agent = 1; 1627 else 1628 error("Could not connect to agent \"%s\": %s", 1629 options.host_key_agent, ssh_err(r)); 1630 } 1631 1632 for (i = 0; i < options.num_host_key_files; i++) { 1633 if (options.host_key_files[i] == NULL) 1634 continue; 1635 if ((r = sshkey_load_private(options.host_key_files[i], "", 1636 &key, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR) 1637 error("Error loading host key \"%s\": %s", 1638 options.host_key_files[i], ssh_err(r)); 1639 if ((r = sshkey_load_public(options.host_key_files[i], 1640 &pubkey, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR) 1641 error("Error loading host key \"%s\": %s", 1642 options.host_key_files[i], ssh_err(r)); 1643 if (pubkey == NULL && key != NULL) 1644 if ((r = sshkey_from_private(key, &pubkey)) != 0) 1645 fatal("Could not demote key: \"%s\": %s", 1646 options.host_key_files[i], ssh_err(r)); 1647 sensitive_data.host_keys[i] = key; 1648 sensitive_data.host_pubkeys[i] = pubkey; 1649 1650 if (key == NULL && pubkey != NULL && have_agent) { 1651 debug("will rely on agent for hostkey %s", 1652 options.host_key_files[i]); 1653 keytype = pubkey->type; 1654 } else if (key != NULL) { 1655 keytype = key->type; 1656 accumulate_host_timing_secret(cfg, key); 1657 } else { 1658 error("Could not load host key: %s", 1659 options.host_key_files[i]); 1660 sensitive_data.host_keys[i] = NULL; 1661 sensitive_data.host_pubkeys[i] = NULL; 1662 continue; 1663 } 1664 1665 switch (keytype) { 1666 case KEY_RSA: 1667 case KEY_DSA: 1668 case KEY_ECDSA: 1669 case KEY_ED25519: 1670 case KEY_XMSS: 1671 if (have_agent || key != NULL) 1672 sensitive_data.have_ssh2_key = 1; 1673 break; 1674 } 1675 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash, 1676 SSH_FP_DEFAULT)) == NULL) 1677 fatal("sshkey_fingerprint failed"); 1678 debug("%s host key #%d: %s %s", 1679 key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp); 1680 free(fp); 1681 } 1682 accumulate_host_timing_secret(cfg, NULL); 1683 if (!sensitive_data.have_ssh2_key) { 1684 logit("sshd: no hostkeys available -- exiting."); 1685 exit(1); 1686 } 1687 1688 /* 1689 * Load certificates. They are stored in an array at identical 1690 * indices to the public keys that they relate to. 1691 */ 1692 sensitive_data.host_certificates = xcalloc(options.num_host_key_files, 1693 sizeof(struct sshkey *)); 1694 for (i = 0; i < options.num_host_key_files; i++) 1695 sensitive_data.host_certificates[i] = NULL; 1696 1697 for (i = 0; i < options.num_host_cert_files; i++) { 1698 if (options.host_cert_files[i] == NULL) 1699 continue; 1700 if ((r = sshkey_load_public(options.host_cert_files[i], 1701 &key, NULL)) != 0) { 1702 error("Could not load host certificate \"%s\": %s", 1703 options.host_cert_files[i], ssh_err(r)); 1704 continue; 1705 } 1706 if (!sshkey_is_cert(key)) { 1707 error("Certificate file is not a certificate: %s", 1708 options.host_cert_files[i]); 1709 sshkey_free(key); 1710 continue; 1711 } 1712 /* Find matching private key */ 1713 for (j = 0; j < options.num_host_key_files; j++) { 1714 if (sshkey_equal_public(key, 1715 sensitive_data.host_keys[j])) { 1716 sensitive_data.host_certificates[j] = key; 1717 break; 1718 } 1719 } 1720 if (j >= options.num_host_key_files) { 1721 error("No matching private key for certificate: %s", 1722 options.host_cert_files[i]); 1723 sshkey_free(key); 1724 continue; 1725 } 1726 sensitive_data.host_certificates[j] = key; 1727 debug("host certificate: #%u type %d %s", j, key->type, 1728 sshkey_type(key)); 1729 } 1730 1731 if (use_privsep) { 1732 struct stat st; 1733 1734 if (getpwnam(SSH_PRIVSEP_USER) == NULL) 1735 fatal("Privilege separation user %s does not exist", 1736 SSH_PRIVSEP_USER); 1737 endpwent(); 1738 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || 1739 (S_ISDIR(st.st_mode) == 0)) 1740 fatal("Missing privilege separation directory: %s", 1741 _PATH_PRIVSEP_CHROOT_DIR); 1742 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) 1743 fatal("%s must be owned by root and not group or " 1744 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); 1745 } 1746 1747 if (test_flag > 1) { 1748 /* 1749 * If no connection info was provided by -C then use 1750 * use a blank one that will cause no predicate to match. 1751 */ 1752 if (connection_info == NULL) 1753 connection_info = get_connection_info(0, 0); 1754 parse_server_match_config(&options, connection_info); 1755 dump_config(&options); 1756 } 1757 1758 /* Configuration looks good, so exit if in test mode. */ 1759 if (test_flag) 1760 exit(0); 1761 1762 if (rexec_flag) { 1763 if (rexec_argc < 0) 1764 fatal("rexec_argc %d < 0", rexec_argc); 1765 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); 1766 for (i = 0; i < (u_int)rexec_argc; i++) { 1767 debug("rexec_argv[%d]='%s'", i, saved_argv[i]); 1768 rexec_argv[i] = saved_argv[i]; 1769 } 1770 rexec_argv[rexec_argc] = "-R"; 1771 rexec_argv[rexec_argc + 1] = NULL; 1772 } 1773 1774 /* Ensure that umask disallows at least group and world write */ 1775 new_umask = umask(0077) | 0022; 1776 (void) umask(new_umask); 1777 1778 /* Initialize the log (it is reinitialized below in case we forked). */ 1779 if (debug_flag && (!inetd_flag || rexeced_flag)) 1780 log_stderr = 1; 1781 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1782 1783 /* 1784 * If not in debugging mode, not started from inetd and not already 1785 * daemonized (eg re-exec via SIGHUP), disconnect from the controlling 1786 * terminal, and fork. The original process exits. 1787 */ 1788 already_daemon = daemonized(); 1789 if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) { 1790 1791 if (daemon(0, 0) < 0) 1792 fatal("daemon() failed: %.200s", strerror(errno)); 1793 1794 disconnect_controlling_tty(); 1795 } 1796 /* Reinitialize the log (because of the fork above). */ 1797 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1798 1799 /* Chdir to the root directory so that the current disk can be 1800 unmounted if desired. */ 1801 if (chdir("/") == -1) 1802 error("chdir(\"/\"): %s", strerror(errno)); 1803 1804 /* ignore SIGPIPE */ 1805 signal(SIGPIPE, SIG_IGN); 1806 1807 /* Get a connection, either from inetd or a listening TCP socket */ 1808 if (inetd_flag) { 1809 server_accept_inetd(&sock_in, &sock_out); 1810 } else { 1811 server_listen(); 1812 1813 signal(SIGHUP, sighup_handler); 1814 signal(SIGCHLD, main_sigchld_handler); 1815 signal(SIGTERM, sigterm_handler); 1816 signal(SIGQUIT, sigterm_handler); 1817 1818 /* 1819 * Write out the pid file after the sigterm handler 1820 * is setup and the listen sockets are bound 1821 */ 1822 if (options.pid_file != NULL && !debug_flag) { 1823 FILE *f = fopen(options.pid_file, "w"); 1824 1825 if (f == NULL) { 1826 error("Couldn't create pid file \"%s\": %s", 1827 options.pid_file, strerror(errno)); 1828 } else { 1829 fprintf(f, "%ld\n", (long) getpid()); 1830 fclose(f); 1831 } 1832 } 1833 1834 /* Accept a connection and return in a forked child */ 1835 server_accept_loop(&sock_in, &sock_out, 1836 &newsock, config_s); 1837 } 1838 1839 /* This is the child processing a new connection. */ 1840 setproctitle("%s", "[accepted]"); 1841 1842 /* 1843 * Create a new session and process group since the 4.4BSD 1844 * setlogin() affects the entire process group. We don't 1845 * want the child to be able to affect the parent. 1846 */ 1847 if (!debug_flag && !inetd_flag && setsid() < 0) 1848 error("setsid: %.100s", strerror(errno)); 1849 1850 if (rexec_flag) { 1851 int fd; 1852 1853 debug("rexec start in %d out %d newsock %d pipe %d sock %d", 1854 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 1855 dup2(newsock, STDIN_FILENO); 1856 dup2(STDIN_FILENO, STDOUT_FILENO); 1857 if (startup_pipe == -1) 1858 close(REEXEC_STARTUP_PIPE_FD); 1859 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) { 1860 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); 1861 close(startup_pipe); 1862 startup_pipe = REEXEC_STARTUP_PIPE_FD; 1863 } 1864 1865 dup2(config_s[1], REEXEC_CONFIG_PASS_FD); 1866 close(config_s[1]); 1867 1868 execv(rexec_argv[0], rexec_argv); 1869 1870 /* Reexec has failed, fall back and continue */ 1871 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); 1872 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); 1873 log_init(__progname, options.log_level, 1874 options.log_facility, log_stderr); 1875 1876 /* Clean up fds */ 1877 close(REEXEC_CONFIG_PASS_FD); 1878 newsock = sock_out = sock_in = dup(STDIN_FILENO); 1879 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1880 dup2(fd, STDIN_FILENO); 1881 dup2(fd, STDOUT_FILENO); 1882 if (fd > STDERR_FILENO) 1883 close(fd); 1884 } 1885 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", 1886 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 1887 } 1888 1889 /* Executed child processes don't need these. */ 1890 fcntl(sock_out, F_SETFD, FD_CLOEXEC); 1891 fcntl(sock_in, F_SETFD, FD_CLOEXEC); 1892 1893 /* 1894 * Disable the key regeneration alarm. We will not regenerate the 1895 * key since we are no longer in a position to give it to anyone. We 1896 * will not restart on SIGHUP since it no longer makes sense. 1897 */ 1898 alarm(0); 1899 signal(SIGALRM, SIG_DFL); 1900 signal(SIGHUP, SIG_DFL); 1901 signal(SIGTERM, SIG_DFL); 1902 signal(SIGQUIT, SIG_DFL); 1903 signal(SIGCHLD, SIG_DFL); 1904 1905 /* 1906 * Register our connection. This turns encryption off because we do 1907 * not have a key. 1908 */ 1909 packet_set_connection(sock_in, sock_out); 1910 packet_set_server(); 1911 ssh = active_state; /* XXX */ 1912 1913 check_ip_options(ssh); 1914 1915 /* Prepare the channels layer */ 1916 channel_init_channels(ssh); 1917 channel_set_af(ssh, options.address_family); 1918 process_permitopen(ssh, &options); 1919 1920 /* Set SO_KEEPALIVE if requested. */ 1921 if (options.tcp_keep_alive && packet_connection_is_on_socket() && 1922 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) 1923 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 1924 1925 if ((remote_port = ssh_remote_port(ssh)) < 0) { 1926 debug("ssh_remote_port failed"); 1927 cleanup_exit(255); 1928 } 1929 1930 /* 1931 * The rest of the code depends on the fact that 1932 * ssh_remote_ipaddr() caches the remote ip, even if 1933 * the socket goes away. 1934 */ 1935 remote_ip = ssh_remote_ipaddr(ssh); 1936 1937 rdomain = ssh_packet_rdomain_in(ssh); 1938 1939 /* Log the connection. */ 1940 laddr = get_local_ipaddr(sock_in); 1941 verbose("Connection from %s port %d on %s port %d%s%s%s", 1942 remote_ip, remote_port, laddr, ssh_local_port(ssh), 1943 rdomain == NULL ? "" : " rdomain \"", 1944 rdomain == NULL ? "" : rdomain, 1945 rdomain == NULL ? "" : "\""); 1946 free(laddr); 1947 1948 /* 1949 * We don't want to listen forever unless the other side 1950 * successfully authenticates itself. So we set up an alarm which is 1951 * cleared after successful authentication. A limit of zero 1952 * indicates no limit. Note that we don't set the alarm in debugging 1953 * mode; it is just annoying to have the server exit just when you 1954 * are about to discover the bug. 1955 */ 1956 signal(SIGALRM, grace_alarm_handler); 1957 if (!debug_flag) 1958 alarm(options.login_grace_time); 1959 1960 sshd_exchange_identification(ssh, sock_in, sock_out); 1961 packet_set_nonblocking(); 1962 1963 /* allocate authentication context */ 1964 authctxt = xcalloc(1, sizeof(*authctxt)); 1965 1966 /* XXX global for cleanup, access from other modules */ 1967 the_authctxt = authctxt; 1968 1969 /* Set default key authentication options */ 1970 if ((auth_opts = sshauthopt_new_with_keys_defaults()) == NULL) 1971 fatal("allocation failed"); 1972 1973 /* prepare buffer to collect messages to display to user after login */ 1974 if ((loginmsg = sshbuf_new()) == NULL) 1975 fatal("%s: sshbuf_new failed", __func__); 1976 auth_debug_reset(); 1977 1978 if (use_privsep) { 1979 if (privsep_preauth(authctxt) == 1) 1980 goto authenticated; 1981 } else if (have_agent) { 1982 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { 1983 error("Unable to get agent socket: %s", ssh_err(r)); 1984 have_agent = 0; 1985 } 1986 } 1987 1988 /* perform the key exchange */ 1989 /* authenticate user and start session */ 1990 do_ssh2_kex(); 1991 do_authentication2(authctxt); 1992 1993 /* 1994 * If we use privilege separation, the unprivileged child transfers 1995 * the current keystate and exits 1996 */ 1997 if (use_privsep) { 1998 mm_send_keystate(pmonitor); 1999 packet_clear_keys(); 2000 exit(0); 2001 } 2002 2003 authenticated: 2004 /* 2005 * Cancel the alarm we set to limit the time taken for 2006 * authentication. 2007 */ 2008 alarm(0); 2009 signal(SIGALRM, SIG_DFL); 2010 authctxt->authenticated = 1; 2011 if (startup_pipe != -1) { 2012 close(startup_pipe); 2013 startup_pipe = -1; 2014 } 2015 2016 if (options.routing_domain != NULL) 2017 set_process_rdomain(ssh, options.routing_domain); 2018 2019 /* 2020 * In privilege separation, we fork another child and prepare 2021 * file descriptor passing. 2022 */ 2023 if (use_privsep) { 2024 privsep_postauth(authctxt); 2025 /* the monitor process [priv] will not return */ 2026 } 2027 2028 packet_set_timeout(options.client_alive_interval, 2029 options.client_alive_count_max); 2030 2031 /* Try to send all our hostkeys to the client */ 2032 notify_hostkeys(ssh); 2033 2034 /* Start session. */ 2035 do_authenticated(ssh, authctxt); 2036 2037 /* The connection has been terminated. */ 2038 packet_get_bytes(&ibytes, &obytes); 2039 verbose("Transferred: sent %llu, received %llu bytes", 2040 (unsigned long long)obytes, (unsigned long long)ibytes); 2041 2042 verbose("Closing connection to %.500s port %d", remote_ip, remote_port); 2043 packet_close(); 2044 2045 if (use_privsep) 2046 mm_terminate(); 2047 2048 exit(0); 2049 } 2050 2051 int 2052 sshd_hostkey_sign(struct sshkey *privkey, struct sshkey *pubkey, 2053 u_char **signature, size_t *slenp, const u_char *data, size_t dlen, 2054 const char *alg, u_int flag) 2055 { 2056 int r; 2057 2058 if (privkey) { 2059 if (PRIVSEP(sshkey_sign(privkey, signature, slenp, data, dlen, 2060 alg, datafellows)) < 0) 2061 fatal("%s: key_sign failed", __func__); 2062 } else if (use_privsep) { 2063 if (mm_sshkey_sign(pubkey, signature, slenp, data, dlen, 2064 alg, datafellows) < 0) 2065 fatal("%s: pubkey_sign failed", __func__); 2066 } else { 2067 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slenp, 2068 data, dlen, alg, datafellows)) != 0) 2069 fatal("%s: ssh_agent_sign failed: %s", 2070 __func__, ssh_err(r)); 2071 } 2072 return 0; 2073 } 2074 2075 /* SSH2 key exchange */ 2076 static void 2077 do_ssh2_kex(void) 2078 { 2079 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER }; 2080 struct kex *kex; 2081 int r; 2082 2083 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 2084 options.kex_algorithms); 2085 myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal( 2086 options.ciphers); 2087 myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal( 2088 options.ciphers); 2089 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 2090 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 2091 2092 if (options.compression == COMP_NONE) { 2093 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2094 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; 2095 } 2096 2097 if (options.rekey_limit || options.rekey_interval) 2098 packet_set_rekey_limits(options.rekey_limit, 2099 options.rekey_interval); 2100 2101 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal( 2102 list_hostkey_types()); 2103 2104 /* start key exchange */ 2105 if ((r = kex_setup(active_state, myproposal)) != 0) 2106 fatal("kex_setup: %s", ssh_err(r)); 2107 kex = active_state->kex; 2108 #ifdef WITH_OPENSSL 2109 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 2110 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 2111 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server; 2112 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server; 2113 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server; 2114 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 2115 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 2116 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 2117 #endif 2118 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 2119 kex->server = 1; 2120 kex->client_version_string=client_version_string; 2121 kex->server_version_string=server_version_string; 2122 kex->load_host_public_key=&get_hostkey_public_by_type; 2123 kex->load_host_private_key=&get_hostkey_private_by_type; 2124 kex->host_key_index=&get_hostkey_index; 2125 kex->sign = sshd_hostkey_sign; 2126 2127 ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done); 2128 2129 session_id2 = kex->session_id; 2130 session_id2_len = kex->session_id_len; 2131 2132 #ifdef DEBUG_KEXDH 2133 /* send 1st encrypted/maced/compressed message */ 2134 packet_start(SSH2_MSG_IGNORE); 2135 packet_put_cstring("markus"); 2136 packet_send(); 2137 packet_write_wait(); 2138 #endif 2139 debug("KEX done"); 2140 } 2141 2142 /* server specific fatal cleanup */ 2143 void 2144 cleanup_exit(int i) 2145 { 2146 struct ssh *ssh = active_state; /* XXX */ 2147 2148 if (the_authctxt) { 2149 do_cleanup(ssh, the_authctxt); 2150 if (use_privsep && privsep_is_preauth && 2151 pmonitor != NULL && pmonitor->m_pid > 1) { 2152 debug("Killing privsep child %d", pmonitor->m_pid); 2153 if (kill(pmonitor->m_pid, SIGKILL) != 0 && 2154 errno != ESRCH) 2155 error("%s: kill(%d): %s", __func__, 2156 pmonitor->m_pid, strerror(errno)); 2157 } 2158 } 2159 _exit(i); 2160 } 2161