1 /* $OpenBSD: sshd.c,v 1.450 2015/05/24 23:39:16 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 "includes.h" 46 __RCSID("$FreeBSD$"); 47 48 #include <sys/types.h> 49 #include <sys/ioctl.h> 50 #include <sys/mman.h> 51 #include <sys/socket.h> 52 #ifdef HAVE_SYS_STAT_H 53 # include <sys/stat.h> 54 #endif 55 #ifdef HAVE_SYS_TIME_H 56 # include <sys/time.h> 57 #endif 58 #include "openbsd-compat/sys-tree.h" 59 #include "openbsd-compat/sys-queue.h" 60 #include <sys/wait.h> 61 62 #include <errno.h> 63 #include <fcntl.h> 64 #include <netdb.h> 65 #ifdef HAVE_PATHS_H 66 #include <paths.h> 67 #endif 68 #include <grp.h> 69 #include <pwd.h> 70 #include <signal.h> 71 #include <stdarg.h> 72 #include <stdio.h> 73 #include <stdlib.h> 74 #include <string.h> 75 #include <unistd.h> 76 #include <limits.h> 77 78 #ifdef WITH_OPENSSL 79 #include <openssl/dh.h> 80 #include <openssl/bn.h> 81 #include <openssl/rand.h> 82 #include "openbsd-compat/openssl-compat.h" 83 #endif 84 85 #ifdef HAVE_SECUREWARE 86 #include <sys/security.h> 87 #include <prot.h> 88 #endif 89 90 #ifdef __FreeBSD__ 91 #include <resolv.h> 92 #if defined(GSSAPI) && defined(HAVE_GSSAPI_GSSAPI_H) 93 #include <gssapi/gssapi.h> 94 #elif defined(GSSAPI) && defined(HAVE_GSSAPI_H) 95 #include <gssapi.h> 96 #endif 97 #endif 98 99 #include "xmalloc.h" 100 #include "ssh.h" 101 #include "ssh1.h" 102 #include "ssh2.h" 103 #include "rsa.h" 104 #include "sshpty.h" 105 #include "packet.h" 106 #include "log.h" 107 #include "buffer.h" 108 #include "misc.h" 109 #include "servconf.h" 110 #include "uidswap.h" 111 #include "compat.h" 112 #include "cipher.h" 113 #include "digest.h" 114 #include "key.h" 115 #include "kex.h" 116 #include "myproposal.h" 117 #include "authfile.h" 118 #include "pathnames.h" 119 #include "atomicio.h" 120 #include "canohost.h" 121 #include "hostfile.h" 122 #include "auth.h" 123 #include "authfd.h" 124 #include "msg.h" 125 #include "dispatch.h" 126 #include "channels.h" 127 #include "session.h" 128 #include "monitor_mm.h" 129 #include "monitor.h" 130 #ifdef GSSAPI 131 #include "ssh-gss.h" 132 #endif 133 #include "monitor_wrap.h" 134 #include "roaming.h" 135 #include "ssh-sandbox.h" 136 #include "version.h" 137 #include "ssherr.h" 138 139 #ifdef LIBWRAP 140 #include <tcpd.h> 141 #include <syslog.h> 142 int allow_severity; 143 int deny_severity; 144 #endif /* LIBWRAP */ 145 146 #ifndef O_NOCTTY 147 #define O_NOCTTY 0 148 #endif 149 150 /* Re-exec fds */ 151 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) 152 #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) 153 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) 154 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) 155 156 extern char *__progname; 157 158 /* Server configuration options. */ 159 ServerOptions options; 160 161 /* Name of the server configuration file. */ 162 char *config_file_name = _PATH_SERVER_CONFIG_FILE; 163 164 /* 165 * Debug mode flag. This can be set on the command line. If debug 166 * mode is enabled, extra debugging output will be sent to the system 167 * log, the daemon will not go to background, and will exit after processing 168 * the first connection. 169 */ 170 int debug_flag = 0; 171 172 /* Flag indicating that the daemon should only test the configuration and keys. */ 173 int test_flag = 0; 174 175 /* Flag indicating that the daemon is being started from inetd. */ 176 int inetd_flag = 0; 177 178 /* Flag indicating that sshd should not detach and become a daemon. */ 179 int no_daemon_flag = 0; 180 181 /* debug goes to stderr unless inetd_flag is set */ 182 int log_stderr = 0; 183 184 /* Saved arguments to main(). */ 185 char **saved_argv; 186 int saved_argc; 187 188 /* re-exec */ 189 int rexeced_flag = 0; 190 int rexec_flag = 1; 191 int rexec_argc = 0; 192 char **rexec_argv; 193 194 /* 195 * The sockets that the server is listening; this is used in the SIGHUP 196 * signal handler. 197 */ 198 #define MAX_LISTEN_SOCKS 16 199 int listen_socks[MAX_LISTEN_SOCKS]; 200 int num_listen_socks = 0; 201 202 /* 203 * the client's version string, passed by sshd2 in compat mode. if != NULL, 204 * sshd will skip the version-number exchange 205 */ 206 char *client_version_string = NULL; 207 char *server_version_string = NULL; 208 209 /* Daemon's agent connection */ 210 int auth_sock = -1; 211 int have_agent = 0; 212 213 /* 214 * Any really sensitive data in the application is contained in this 215 * structure. The idea is that this structure could be locked into memory so 216 * that the pages do not get written into swap. However, there are some 217 * problems. The private key contains BIGNUMs, and we do not (in principle) 218 * have access to the internals of them, and locking just the structure is 219 * not very useful. Currently, memory locking is not implemented. 220 */ 221 struct { 222 Key *server_key; /* ephemeral server key */ 223 Key *ssh1_host_key; /* ssh1 host key */ 224 Key **host_keys; /* all private host keys */ 225 Key **host_pubkeys; /* all public host keys */ 226 Key **host_certificates; /* all public host certificates */ 227 int have_ssh1_key; 228 int have_ssh2_key; 229 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; 230 } sensitive_data; 231 232 /* 233 * Flag indicating whether the RSA server key needs to be regenerated. 234 * Is set in the SIGALRM handler and cleared when the key is regenerated. 235 */ 236 static volatile sig_atomic_t key_do_regen = 0; 237 238 /* This is set to true when a signal is received. */ 239 static volatile sig_atomic_t received_sighup = 0; 240 static volatile sig_atomic_t received_sigterm = 0; 241 242 /* session identifier, used by RSA-auth */ 243 u_char session_id[16]; 244 245 /* same for ssh2 */ 246 u_char *session_id2 = NULL; 247 u_int session_id2_len = 0; 248 249 /* record remote hostname or ip */ 250 u_int utmp_len = HOST_NAME_MAX+1; 251 252 /* options.max_startup sized array of fd ints */ 253 int *startup_pipes = NULL; 254 int startup_pipe; /* in child */ 255 256 /* variables used for privilege separation */ 257 int use_privsep = -1; 258 struct monitor *pmonitor = NULL; 259 int privsep_is_preauth = 1; 260 261 /* global authentication context */ 262 Authctxt *the_authctxt = NULL; 263 264 /* sshd_config buffer */ 265 Buffer cfg; 266 267 /* message to be displayed after login */ 268 Buffer loginmsg; 269 270 /* Unprivileged user */ 271 struct passwd *privsep_pw = NULL; 272 273 /* Prototypes for various functions defined later in this file. */ 274 void destroy_sensitive_data(void); 275 void demote_sensitive_data(void); 276 277 #ifdef WITH_SSH1 278 static void do_ssh1_kex(void); 279 #endif 280 static void do_ssh2_kex(void); 281 282 /* 283 * Close all listening sockets 284 */ 285 static void 286 close_listen_socks(void) 287 { 288 int i; 289 290 for (i = 0; i < num_listen_socks; i++) 291 close(listen_socks[i]); 292 num_listen_socks = -1; 293 } 294 295 static void 296 close_startup_pipes(void) 297 { 298 int i; 299 300 if (startup_pipes) 301 for (i = 0; i < options.max_startups; i++) 302 if (startup_pipes[i] != -1) 303 close(startup_pipes[i]); 304 } 305 306 /* 307 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; 308 * the effect is to reread the configuration file (and to regenerate 309 * the server key). 310 */ 311 312 /*ARGSUSED*/ 313 static void 314 sighup_handler(int sig) 315 { 316 int save_errno = errno; 317 318 received_sighup = 1; 319 signal(SIGHUP, sighup_handler); 320 errno = save_errno; 321 } 322 323 /* 324 * Called from the main program after receiving SIGHUP. 325 * Restarts the server. 326 */ 327 static void 328 sighup_restart(void) 329 { 330 logit("Received SIGHUP; restarting."); 331 platform_pre_restart(); 332 close_listen_socks(); 333 close_startup_pipes(); 334 alarm(0); /* alarm timer persists across exec */ 335 signal(SIGHUP, SIG_IGN); /* will be restored after exec */ 336 execv(saved_argv[0], saved_argv); 337 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], 338 strerror(errno)); 339 exit(1); 340 } 341 342 /* 343 * Generic signal handler for terminating signals in the master daemon. 344 */ 345 /*ARGSUSED*/ 346 static void 347 sigterm_handler(int sig) 348 { 349 received_sigterm = sig; 350 } 351 352 /* 353 * SIGCHLD handler. This is called whenever a child dies. This will then 354 * reap any zombies left by exited children. 355 */ 356 /*ARGSUSED*/ 357 static void 358 main_sigchld_handler(int sig) 359 { 360 int save_errno = errno; 361 pid_t pid; 362 int status; 363 364 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 365 (pid < 0 && errno == EINTR)) 366 ; 367 368 signal(SIGCHLD, main_sigchld_handler); 369 errno = save_errno; 370 } 371 372 /* 373 * Signal handler for the alarm after the login grace period has expired. 374 */ 375 /*ARGSUSED*/ 376 static void 377 grace_alarm_handler(int sig) 378 { 379 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) 380 kill(pmonitor->m_pid, SIGALRM); 381 382 /* 383 * Try to kill any processes that we have spawned, E.g. authorized 384 * keys command helpers. 385 */ 386 if (getpgid(0) == getpid()) { 387 signal(SIGTERM, SIG_IGN); 388 kill(0, SIGTERM); 389 } 390 391 /* Log error and exit. */ 392 sigdie("Timeout before authentication for %s", get_remote_ipaddr()); 393 } 394 395 /* 396 * Signal handler for the key regeneration alarm. Note that this 397 * alarm only occurs in the daemon waiting for connections, and it does not 398 * do anything with the private key or random state before forking. 399 * Thus there should be no concurrency control/asynchronous execution 400 * problems. 401 */ 402 static void 403 generate_ephemeral_server_key(void) 404 { 405 verbose("Generating %s%d bit RSA key.", 406 sensitive_data.server_key ? "new " : "", options.server_key_bits); 407 if (sensitive_data.server_key != NULL) 408 key_free(sensitive_data.server_key); 409 sensitive_data.server_key = key_generate(KEY_RSA1, 410 options.server_key_bits); 411 verbose("RSA key generation complete."); 412 413 arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); 414 } 415 416 /*ARGSUSED*/ 417 static void 418 key_regeneration_alarm(int sig) 419 { 420 int save_errno = errno; 421 422 signal(SIGALRM, SIG_DFL); 423 errno = save_errno; 424 key_do_regen = 1; 425 } 426 427 static void 428 sshd_exchange_identification(int sock_in, int sock_out) 429 { 430 u_int i; 431 int mismatch; 432 int remote_major, remote_minor; 433 int major, minor; 434 char *s, *newline = "\n"; 435 char buf[256]; /* Must not be larger than remote_version. */ 436 char remote_version[256]; /* Must be at least as big as buf. */ 437 438 if ((options.protocol & SSH_PROTO_1) && 439 (options.protocol & SSH_PROTO_2)) { 440 major = PROTOCOL_MAJOR_1; 441 minor = 99; 442 } else if (options.protocol & SSH_PROTO_2) { 443 major = PROTOCOL_MAJOR_2; 444 minor = PROTOCOL_MINOR_2; 445 newline = "\r\n"; 446 } else { 447 major = PROTOCOL_MAJOR_1; 448 minor = PROTOCOL_MINOR_1; 449 } 450 451 xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s", 452 major, minor, SSH_VERSION, 453 *options.version_addendum == '\0' ? "" : " ", 454 options.version_addendum, newline); 455 456 /* Send our protocol version identification. */ 457 if (roaming_atomicio(vwrite, sock_out, server_version_string, 458 strlen(server_version_string)) 459 != strlen(server_version_string)) { 460 logit("Could not write ident string to %s", get_remote_ipaddr()); 461 cleanup_exit(255); 462 } 463 464 /* Read other sides version identification. */ 465 memset(buf, 0, sizeof(buf)); 466 for (i = 0; i < sizeof(buf) - 1; i++) { 467 if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) { 468 logit("Did not receive identification string from %s", 469 get_remote_ipaddr()); 470 cleanup_exit(255); 471 } 472 if (buf[i] == '\r') { 473 buf[i] = 0; 474 /* Kludge for F-Secure Macintosh < 1.0.2 */ 475 if (i == 12 && 476 strncmp(buf, "SSH-1.5-W1.0", 12) == 0) 477 break; 478 continue; 479 } 480 if (buf[i] == '\n') { 481 buf[i] = 0; 482 break; 483 } 484 } 485 buf[sizeof(buf) - 1] = 0; 486 client_version_string = xstrdup(buf); 487 488 /* 489 * Check that the versions match. In future this might accept 490 * several versions and set appropriate flags to handle them. 491 */ 492 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", 493 &remote_major, &remote_minor, remote_version) != 3) { 494 s = "Protocol mismatch.\n"; 495 (void) atomicio(vwrite, sock_out, s, strlen(s)); 496 logit("Bad protocol version identification '%.100s' " 497 "from %s port %d", client_version_string, 498 get_remote_ipaddr(), get_remote_port()); 499 close(sock_in); 500 close(sock_out); 501 cleanup_exit(255); 502 } 503 debug("Client protocol version %d.%d; client software version %.100s", 504 remote_major, remote_minor, remote_version); 505 506 active_state->compat = compat_datafellows(remote_version); 507 508 if ((datafellows & SSH_BUG_PROBE) != 0) { 509 logit("probed from %s with %s. Don't panic.", 510 get_remote_ipaddr(), client_version_string); 511 cleanup_exit(255); 512 } 513 if ((datafellows & SSH_BUG_SCANNER) != 0) { 514 logit("scanned from %s with %s. Don't panic.", 515 get_remote_ipaddr(), client_version_string); 516 cleanup_exit(255); 517 } 518 if ((datafellows & SSH_BUG_RSASIGMD5) != 0) { 519 logit("Client version \"%.100s\" uses unsafe RSA signature " 520 "scheme; disabling use of RSA keys", remote_version); 521 } 522 if ((datafellows & SSH_BUG_DERIVEKEY) != 0) { 523 fatal("Client version \"%.100s\" uses unsafe key agreement; " 524 "refusing connection", remote_version); 525 } 526 527 mismatch = 0; 528 switch (remote_major) { 529 case 1: 530 if (remote_minor == 99) { 531 if (options.protocol & SSH_PROTO_2) 532 enable_compat20(); 533 else 534 mismatch = 1; 535 break; 536 } 537 if (!(options.protocol & SSH_PROTO_1)) { 538 mismatch = 1; 539 break; 540 } 541 if (remote_minor < 3) { 542 packet_disconnect("Your ssh version is too old and " 543 "is no longer supported. Please install a newer version."); 544 } else if (remote_minor == 3) { 545 /* note that this disables agent-forwarding */ 546 enable_compat13(); 547 } 548 break; 549 case 2: 550 if (options.protocol & SSH_PROTO_2) { 551 enable_compat20(); 552 break; 553 } 554 /* FALLTHROUGH */ 555 default: 556 mismatch = 1; 557 break; 558 } 559 chop(server_version_string); 560 debug("Local version string %.200s", server_version_string); 561 562 if (mismatch) { 563 s = "Protocol major versions differ.\n"; 564 (void) atomicio(vwrite, sock_out, s, strlen(s)); 565 close(sock_in); 566 close(sock_out); 567 logit("Protocol major versions differ for %s: %.200s vs. %.200s", 568 get_remote_ipaddr(), 569 server_version_string, client_version_string); 570 cleanup_exit(255); 571 } 572 } 573 574 /* Destroy the host and server keys. They will no longer be needed. */ 575 void 576 destroy_sensitive_data(void) 577 { 578 int i; 579 580 if (sensitive_data.server_key) { 581 key_free(sensitive_data.server_key); 582 sensitive_data.server_key = NULL; 583 } 584 for (i = 0; i < options.num_host_key_files; i++) { 585 if (sensitive_data.host_keys[i]) { 586 key_free(sensitive_data.host_keys[i]); 587 sensitive_data.host_keys[i] = NULL; 588 } 589 if (sensitive_data.host_certificates[i]) { 590 key_free(sensitive_data.host_certificates[i]); 591 sensitive_data.host_certificates[i] = NULL; 592 } 593 } 594 sensitive_data.ssh1_host_key = NULL; 595 explicit_bzero(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); 596 } 597 598 /* Demote private to public keys for network child */ 599 void 600 demote_sensitive_data(void) 601 { 602 Key *tmp; 603 int i; 604 605 if (sensitive_data.server_key) { 606 tmp = key_demote(sensitive_data.server_key); 607 key_free(sensitive_data.server_key); 608 sensitive_data.server_key = tmp; 609 } 610 611 for (i = 0; i < options.num_host_key_files; i++) { 612 if (sensitive_data.host_keys[i]) { 613 tmp = key_demote(sensitive_data.host_keys[i]); 614 key_free(sensitive_data.host_keys[i]); 615 sensitive_data.host_keys[i] = tmp; 616 if (tmp->type == KEY_RSA1) 617 sensitive_data.ssh1_host_key = tmp; 618 } 619 /* Certs do not need demotion */ 620 } 621 622 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ 623 } 624 625 static void 626 privsep_preauth_child(void) 627 { 628 u_int32_t rnd[256]; 629 gid_t gidset[1]; 630 631 /* Enable challenge-response authentication for privilege separation */ 632 privsep_challenge_enable(); 633 634 #ifdef GSSAPI 635 /* Cache supported mechanism OIDs for later use */ 636 if (options.gss_authentication) 637 ssh_gssapi_prepare_supported_oids(); 638 #endif 639 640 arc4random_stir(); 641 arc4random_buf(rnd, sizeof(rnd)); 642 #ifdef WITH_OPENSSL 643 RAND_seed(rnd, sizeof(rnd)); 644 #endif 645 explicit_bzero(rnd, sizeof(rnd)); 646 647 /* Demote the private keys to public keys. */ 648 demote_sensitive_data(); 649 650 /* Change our root directory */ 651 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) 652 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, 653 strerror(errno)); 654 if (chdir("/") == -1) 655 fatal("chdir(\"/\"): %s", strerror(errno)); 656 657 /* Drop our privileges */ 658 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, 659 (u_int)privsep_pw->pw_gid); 660 #if 0 661 /* XXX not ready, too heavy after chroot */ 662 do_setusercontext(privsep_pw); 663 #else 664 gidset[0] = privsep_pw->pw_gid; 665 if (setgroups(1, gidset) < 0) 666 fatal("setgroups: %.100s", strerror(errno)); 667 permanently_set_uid(privsep_pw); 668 #endif 669 } 670 671 static int 672 privsep_preauth(Authctxt *authctxt) 673 { 674 int status, r; 675 pid_t pid; 676 struct ssh_sandbox *box = NULL; 677 678 /* Set up unprivileged child process to deal with network data */ 679 pmonitor = monitor_init(); 680 /* Store a pointer to the kex for later rekeying */ 681 pmonitor->m_pkex = &active_state->kex; 682 683 if (use_privsep == PRIVSEP_ON) 684 box = ssh_sandbox_init(pmonitor); 685 pid = fork(); 686 if (pid == -1) { 687 fatal("fork of unprivileged child failed"); 688 } else if (pid != 0) { 689 debug2("Network child is on pid %ld", (long)pid); 690 691 pmonitor->m_pid = pid; 692 if (have_agent) { 693 r = ssh_get_authentication_socket(&auth_sock); 694 if (r != 0) { 695 error("Could not get agent socket: %s", 696 ssh_err(r)); 697 have_agent = 0; 698 } 699 } 700 if (box != NULL) 701 ssh_sandbox_parent_preauth(box, pid); 702 monitor_child_preauth(authctxt, pmonitor); 703 704 /* Sync memory */ 705 monitor_sync(pmonitor); 706 707 /* Wait for the child's exit status */ 708 while (waitpid(pid, &status, 0) < 0) { 709 if (errno == EINTR) 710 continue; 711 pmonitor->m_pid = -1; 712 fatal("%s: waitpid: %s", __func__, strerror(errno)); 713 } 714 privsep_is_preauth = 0; 715 pmonitor->m_pid = -1; 716 if (WIFEXITED(status)) { 717 if (WEXITSTATUS(status) != 0) 718 fatal("%s: preauth child exited with status %d", 719 __func__, WEXITSTATUS(status)); 720 } else if (WIFSIGNALED(status)) 721 fatal("%s: preauth child terminated by signal %d", 722 __func__, WTERMSIG(status)); 723 if (box != NULL) 724 ssh_sandbox_parent_finish(box); 725 return 1; 726 } else { 727 /* child */ 728 close(pmonitor->m_sendfd); 729 close(pmonitor->m_log_recvfd); 730 731 /* Arrange for logging to be sent to the monitor */ 732 set_log_handler(mm_log_handler, pmonitor); 733 734 /* Demote the child */ 735 if (getuid() == 0 || geteuid() == 0) 736 privsep_preauth_child(); 737 setproctitle("%s", "[net]"); 738 if (box != NULL) 739 ssh_sandbox_child(box); 740 741 return 0; 742 } 743 } 744 745 static void 746 privsep_postauth(Authctxt *authctxt) 747 { 748 u_int32_t rnd[256]; 749 750 #ifdef DISABLE_FD_PASSING 751 if (1) { 752 #else 753 if (authctxt->pw->pw_uid == 0 || options.use_login) { 754 #endif 755 /* File descriptor passing is broken or root login */ 756 use_privsep = 0; 757 goto skip; 758 } 759 760 /* New socket pair */ 761 monitor_reinit(pmonitor); 762 763 pmonitor->m_pid = fork(); 764 if (pmonitor->m_pid == -1) 765 fatal("fork of unprivileged child failed"); 766 else if (pmonitor->m_pid != 0) { 767 verbose("User child is on pid %ld", (long)pmonitor->m_pid); 768 buffer_clear(&loginmsg); 769 monitor_child_postauth(pmonitor); 770 771 /* NEVERREACHED */ 772 exit(0); 773 } 774 775 /* child */ 776 777 close(pmonitor->m_sendfd); 778 pmonitor->m_sendfd = -1; 779 780 /* Demote the private keys to public keys. */ 781 demote_sensitive_data(); 782 783 arc4random_stir(); 784 arc4random_buf(rnd, sizeof(rnd)); 785 #ifdef WITH_OPENSSL 786 RAND_seed(rnd, sizeof(rnd)); 787 #endif 788 explicit_bzero(rnd, sizeof(rnd)); 789 790 /* Drop privileges */ 791 do_setusercontext(authctxt->pw); 792 793 skip: 794 /* It is safe now to apply the key state */ 795 monitor_apply_keystate(pmonitor); 796 797 /* 798 * Tell the packet layer that authentication was successful, since 799 * this information is not part of the key state. 800 */ 801 packet_set_authenticated(); 802 } 803 804 static char * 805 list_hostkey_types(void) 806 { 807 Buffer b; 808 const char *p; 809 char *ret; 810 int i; 811 Key *key; 812 813 buffer_init(&b); 814 for (i = 0; i < options.num_host_key_files; i++) { 815 key = sensitive_data.host_keys[i]; 816 if (key == NULL) 817 key = sensitive_data.host_pubkeys[i]; 818 if (key == NULL) 819 continue; 820 switch (key->type) { 821 case KEY_RSA: 822 case KEY_DSA: 823 case KEY_ECDSA: 824 case KEY_ED25519: 825 if (buffer_len(&b) > 0) 826 buffer_append(&b, ",", 1); 827 p = key_ssh_name(key); 828 buffer_append(&b, p, strlen(p)); 829 break; 830 } 831 /* If the private key has a cert peer, then list that too */ 832 key = sensitive_data.host_certificates[i]; 833 if (key == NULL) 834 continue; 835 switch (key->type) { 836 case KEY_RSA_CERT_V00: 837 case KEY_DSA_CERT_V00: 838 case KEY_RSA_CERT: 839 case KEY_DSA_CERT: 840 case KEY_ECDSA_CERT: 841 case KEY_ED25519_CERT: 842 if (buffer_len(&b) > 0) 843 buffer_append(&b, ",", 1); 844 p = key_ssh_name(key); 845 buffer_append(&b, p, strlen(p)); 846 break; 847 } 848 } 849 buffer_append(&b, "\0", 1); 850 ret = xstrdup(buffer_ptr(&b)); 851 buffer_free(&b); 852 debug("list_hostkey_types: %s", ret); 853 return ret; 854 } 855 856 static Key * 857 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh) 858 { 859 int i; 860 Key *key; 861 862 for (i = 0; i < options.num_host_key_files; i++) { 863 switch (type) { 864 case KEY_RSA_CERT_V00: 865 case KEY_DSA_CERT_V00: 866 case KEY_RSA_CERT: 867 case KEY_DSA_CERT: 868 case KEY_ECDSA_CERT: 869 case KEY_ED25519_CERT: 870 key = sensitive_data.host_certificates[i]; 871 break; 872 default: 873 key = sensitive_data.host_keys[i]; 874 if (key == NULL && !need_private) 875 key = sensitive_data.host_pubkeys[i]; 876 break; 877 } 878 if (key != NULL && key->type == type && 879 (key->type != KEY_ECDSA || key->ecdsa_nid == nid)) 880 return need_private ? 881 sensitive_data.host_keys[i] : key; 882 } 883 return NULL; 884 } 885 886 Key * 887 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh) 888 { 889 return get_hostkey_by_type(type, nid, 0, ssh); 890 } 891 892 Key * 893 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh) 894 { 895 return get_hostkey_by_type(type, nid, 1, ssh); 896 } 897 898 Key * 899 get_hostkey_by_index(int ind) 900 { 901 if (ind < 0 || ind >= options.num_host_key_files) 902 return (NULL); 903 return (sensitive_data.host_keys[ind]); 904 } 905 906 Key * 907 get_hostkey_public_by_index(int ind, struct ssh *ssh) 908 { 909 if (ind < 0 || ind >= options.num_host_key_files) 910 return (NULL); 911 return (sensitive_data.host_pubkeys[ind]); 912 } 913 914 int 915 get_hostkey_index(Key *key, int compare, struct ssh *ssh) 916 { 917 int i; 918 919 for (i = 0; i < options.num_host_key_files; i++) { 920 if (key_is_cert(key)) { 921 if (key == sensitive_data.host_certificates[i] || 922 (compare && sensitive_data.host_certificates[i] && 923 sshkey_equal(key, 924 sensitive_data.host_certificates[i]))) 925 return (i); 926 } else { 927 if (key == sensitive_data.host_keys[i] || 928 (compare && sensitive_data.host_keys[i] && 929 sshkey_equal(key, sensitive_data.host_keys[i]))) 930 return (i); 931 if (key == sensitive_data.host_pubkeys[i] || 932 (compare && sensitive_data.host_pubkeys[i] && 933 sshkey_equal(key, sensitive_data.host_pubkeys[i]))) 934 return (i); 935 } 936 } 937 return (-1); 938 } 939 940 /* Inform the client of all hostkeys */ 941 static void 942 notify_hostkeys(struct ssh *ssh) 943 { 944 struct sshbuf *buf; 945 struct sshkey *key; 946 int i, nkeys, r; 947 char *fp; 948 949 /* Some clients cannot cope with the hostkeys message, skip those. */ 950 if (datafellows & SSH_BUG_HOSTKEYS) 951 return; 952 953 if ((buf = sshbuf_new()) == NULL) 954 fatal("%s: sshbuf_new", __func__); 955 for (i = nkeys = 0; i < options.num_host_key_files; i++) { 956 key = get_hostkey_public_by_index(i, ssh); 957 if (key == NULL || key->type == KEY_UNSPEC || 958 key->type == KEY_RSA1 || sshkey_is_cert(key)) 959 continue; 960 fp = sshkey_fingerprint(key, options.fingerprint_hash, 961 SSH_FP_DEFAULT); 962 debug3("%s: key %d: %s %s", __func__, i, 963 sshkey_ssh_name(key), fp); 964 free(fp); 965 if (nkeys == 0) { 966 packet_start(SSH2_MSG_GLOBAL_REQUEST); 967 packet_put_cstring("hostkeys-00@openssh.com"); 968 packet_put_char(0); /* want-reply */ 969 } 970 sshbuf_reset(buf); 971 if ((r = sshkey_putb(key, buf)) != 0) 972 fatal("%s: couldn't put hostkey %d: %s", 973 __func__, i, ssh_err(r)); 974 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf)); 975 nkeys++; 976 } 977 debug3("%s: sent %d hostkeys", __func__, nkeys); 978 if (nkeys == 0) 979 fatal("%s: no hostkeys", __func__); 980 packet_send(); 981 sshbuf_free(buf); 982 } 983 984 /* 985 * returns 1 if connection should be dropped, 0 otherwise. 986 * dropping starts at connection #max_startups_begin with a probability 987 * of (max_startups_rate/100). the probability increases linearly until 988 * all connections are dropped for startups > max_startups 989 */ 990 static int 991 drop_connection(int startups) 992 { 993 int p, r; 994 995 if (startups < options.max_startups_begin) 996 return 0; 997 if (startups >= options.max_startups) 998 return 1; 999 if (options.max_startups_rate == 100) 1000 return 1; 1001 1002 p = 100 - options.max_startups_rate; 1003 p *= startups - options.max_startups_begin; 1004 p /= options.max_startups - options.max_startups_begin; 1005 p += options.max_startups_rate; 1006 r = arc4random_uniform(100); 1007 1008 debug("drop_connection: p %d, r %d", p, r); 1009 return (r < p) ? 1 : 0; 1010 } 1011 1012 static void 1013 usage(void) 1014 { 1015 if (options.version_addendum && *options.version_addendum != '\0') 1016 fprintf(stderr, "%s %s, %s\n", 1017 SSH_RELEASE, 1018 options.version_addendum, OPENSSL_VERSION); 1019 else 1020 fprintf(stderr, "%s, %s\n", 1021 SSH_RELEASE, OPENSSL_VERSION); 1022 fprintf(stderr, 1023 "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n" 1024 " [-E log_file] [-f config_file] [-g login_grace_time]\n" 1025 " [-h host_key_file] [-k key_gen_time] [-o option] [-p port]\n" 1026 " [-u len]\n" 1027 ); 1028 exit(1); 1029 } 1030 1031 static void 1032 send_rexec_state(int fd, Buffer *conf) 1033 { 1034 Buffer m; 1035 1036 debug3("%s: entering fd = %d config len %d", __func__, fd, 1037 buffer_len(conf)); 1038 1039 /* 1040 * Protocol from reexec master to child: 1041 * string configuration 1042 * u_int ephemeral_key_follows 1043 * bignum e (only if ephemeral_key_follows == 1) 1044 * bignum n " 1045 * bignum d " 1046 * bignum iqmp " 1047 * bignum p " 1048 * bignum q " 1049 * string rngseed (only if OpenSSL is not self-seeded) 1050 */ 1051 buffer_init(&m); 1052 buffer_put_cstring(&m, buffer_ptr(conf)); 1053 1054 #ifdef WITH_SSH1 1055 if (sensitive_data.server_key != NULL && 1056 sensitive_data.server_key->type == KEY_RSA1) { 1057 buffer_put_int(&m, 1); 1058 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); 1059 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); 1060 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); 1061 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); 1062 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); 1063 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); 1064 } else 1065 #endif 1066 buffer_put_int(&m, 0); 1067 1068 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 1069 rexec_send_rng_seed(&m); 1070 #endif 1071 1072 if (ssh_msg_send(fd, 0, &m) == -1) 1073 fatal("%s: ssh_msg_send failed", __func__); 1074 1075 buffer_free(&m); 1076 1077 debug3("%s: done", __func__); 1078 } 1079 1080 static void 1081 recv_rexec_state(int fd, Buffer *conf) 1082 { 1083 Buffer m; 1084 char *cp; 1085 u_int len; 1086 1087 debug3("%s: entering fd = %d", __func__, fd); 1088 1089 buffer_init(&m); 1090 1091 if (ssh_msg_recv(fd, &m) == -1) 1092 fatal("%s: ssh_msg_recv failed", __func__); 1093 if (buffer_get_char(&m) != 0) 1094 fatal("%s: rexec version mismatch", __func__); 1095 1096 cp = buffer_get_string(&m, &len); 1097 if (conf != NULL) 1098 buffer_append(conf, cp, len + 1); 1099 free(cp); 1100 1101 if (buffer_get_int(&m)) { 1102 #ifdef WITH_SSH1 1103 if (sensitive_data.server_key != NULL) 1104 key_free(sensitive_data.server_key); 1105 sensitive_data.server_key = key_new_private(KEY_RSA1); 1106 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); 1107 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); 1108 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); 1109 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); 1110 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); 1111 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); 1112 if (rsa_generate_additional_parameters( 1113 sensitive_data.server_key->rsa) != 0) 1114 fatal("%s: rsa_generate_additional_parameters " 1115 "error", __func__); 1116 #endif 1117 } 1118 1119 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 1120 rexec_recv_rng_seed(&m); 1121 #endif 1122 1123 buffer_free(&m); 1124 1125 debug3("%s: done", __func__); 1126 } 1127 1128 /* Accept a connection from inetd */ 1129 static void 1130 server_accept_inetd(int *sock_in, int *sock_out) 1131 { 1132 int fd; 1133 1134 startup_pipe = -1; 1135 if (rexeced_flag) { 1136 close(REEXEC_CONFIG_PASS_FD); 1137 *sock_in = *sock_out = dup(STDIN_FILENO); 1138 if (!debug_flag) { 1139 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); 1140 close(REEXEC_STARTUP_PIPE_FD); 1141 } 1142 } else { 1143 *sock_in = dup(STDIN_FILENO); 1144 *sock_out = dup(STDOUT_FILENO); 1145 } 1146 /* 1147 * We intentionally do not close the descriptors 0, 1, and 2 1148 * as our code for setting the descriptors won't work if 1149 * ttyfd happens to be one of those. 1150 */ 1151 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1152 dup2(fd, STDIN_FILENO); 1153 dup2(fd, STDOUT_FILENO); 1154 if (!log_stderr) 1155 dup2(fd, STDERR_FILENO); 1156 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO)) 1157 close(fd); 1158 } 1159 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); 1160 } 1161 1162 /* 1163 * Listen for TCP connections 1164 */ 1165 static void 1166 server_listen(void) 1167 { 1168 int ret, listen_sock, on = 1; 1169 struct addrinfo *ai; 1170 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 1171 int socksize; 1172 socklen_t len; 1173 1174 for (ai = options.listen_addrs; ai; ai = ai->ai_next) { 1175 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 1176 continue; 1177 if (num_listen_socks >= MAX_LISTEN_SOCKS) 1178 fatal("Too many listen sockets. " 1179 "Enlarge MAX_LISTEN_SOCKS"); 1180 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, 1181 ntop, sizeof(ntop), strport, sizeof(strport), 1182 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { 1183 error("getnameinfo failed: %.100s", 1184 ssh_gai_strerror(ret)); 1185 continue; 1186 } 1187 /* Create socket for listening. */ 1188 listen_sock = socket(ai->ai_family, ai->ai_socktype, 1189 ai->ai_protocol); 1190 if (listen_sock < 0) { 1191 /* kernel may not support ipv6 */ 1192 verbose("socket: %.100s", strerror(errno)); 1193 continue; 1194 } 1195 if (set_nonblock(listen_sock) == -1) { 1196 close(listen_sock); 1197 continue; 1198 } 1199 /* 1200 * Set socket options. 1201 * Allow local port reuse in TIME_WAIT. 1202 */ 1203 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, 1204 &on, sizeof(on)) == -1) 1205 error("setsockopt SO_REUSEADDR: %s", strerror(errno)); 1206 1207 /* Only communicate in IPv6 over AF_INET6 sockets. */ 1208 if (ai->ai_family == AF_INET6) 1209 sock_set_v6only(listen_sock); 1210 1211 debug("Bind to port %s on %s.", strport, ntop); 1212 1213 len = sizeof(socksize); 1214 getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, &socksize, &len); 1215 debug("Server TCP RWIN socket size: %d", socksize); 1216 1217 /* Bind the socket to the desired port. */ 1218 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1219 error("Bind to port %s on %s failed: %.200s.", 1220 strport, ntop, strerror(errno)); 1221 close(listen_sock); 1222 continue; 1223 } 1224 listen_socks[num_listen_socks] = listen_sock; 1225 num_listen_socks++; 1226 1227 /* Start listening on the port. */ 1228 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) 1229 fatal("listen on [%s]:%s: %.100s", 1230 ntop, strport, strerror(errno)); 1231 logit("Server listening on %s port %s.", ntop, strport); 1232 } 1233 freeaddrinfo(options.listen_addrs); 1234 1235 if (!num_listen_socks) 1236 fatal("Cannot bind any address."); 1237 } 1238 1239 /* 1240 * The main TCP accept loop. Note that, for the non-debug case, returns 1241 * from this function are in a forked subprocess. 1242 */ 1243 static void 1244 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) 1245 { 1246 fd_set *fdset; 1247 int i, j, ret, maxfd; 1248 int key_used = 0, startups = 0; 1249 int startup_p[2] = { -1 , -1 }; 1250 struct sockaddr_storage from; 1251 socklen_t fromlen; 1252 pid_t pid; 1253 u_char rnd[256]; 1254 1255 /* setup fd set for accept */ 1256 fdset = NULL; 1257 maxfd = 0; 1258 for (i = 0; i < num_listen_socks; i++) 1259 if (listen_socks[i] > maxfd) 1260 maxfd = listen_socks[i]; 1261 /* pipes connected to unauthenticated childs */ 1262 startup_pipes = xcalloc(options.max_startups, sizeof(int)); 1263 for (i = 0; i < options.max_startups; i++) 1264 startup_pipes[i] = -1; 1265 1266 /* 1267 * Stay listening for connections until the system crashes or 1268 * the daemon is killed with a signal. 1269 */ 1270 for (;;) { 1271 if (received_sighup) 1272 sighup_restart(); 1273 if (fdset != NULL) 1274 free(fdset); 1275 fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), 1276 sizeof(fd_mask)); 1277 1278 for (i = 0; i < num_listen_socks; i++) 1279 FD_SET(listen_socks[i], fdset); 1280 for (i = 0; i < options.max_startups; i++) 1281 if (startup_pipes[i] != -1) 1282 FD_SET(startup_pipes[i], fdset); 1283 1284 /* Wait in select until there is a connection. */ 1285 ret = select(maxfd+1, fdset, NULL, NULL, NULL); 1286 if (ret < 0 && errno != EINTR) 1287 error("select: %.100s", strerror(errno)); 1288 if (received_sigterm) { 1289 logit("Received signal %d; terminating.", 1290 (int) received_sigterm); 1291 close_listen_socks(); 1292 if (options.pid_file != NULL) 1293 unlink(options.pid_file); 1294 exit(received_sigterm == SIGTERM ? 0 : 255); 1295 } 1296 if (key_used && key_do_regen) { 1297 generate_ephemeral_server_key(); 1298 key_used = 0; 1299 key_do_regen = 0; 1300 } 1301 if (ret < 0) 1302 continue; 1303 1304 for (i = 0; i < options.max_startups; i++) 1305 if (startup_pipes[i] != -1 && 1306 FD_ISSET(startup_pipes[i], fdset)) { 1307 /* 1308 * the read end of the pipe is ready 1309 * if the child has closed the pipe 1310 * after successful authentication 1311 * or if the child has died 1312 */ 1313 close(startup_pipes[i]); 1314 startup_pipes[i] = -1; 1315 startups--; 1316 } 1317 for (i = 0; i < num_listen_socks; i++) { 1318 if (!FD_ISSET(listen_socks[i], fdset)) 1319 continue; 1320 fromlen = sizeof(from); 1321 *newsock = accept(listen_socks[i], 1322 (struct sockaddr *)&from, &fromlen); 1323 if (*newsock < 0) { 1324 if (errno != EINTR && errno != EWOULDBLOCK && 1325 errno != ECONNABORTED && errno != EAGAIN) 1326 error("accept: %.100s", 1327 strerror(errno)); 1328 if (errno == EMFILE || errno == ENFILE) 1329 usleep(100 * 1000); 1330 continue; 1331 } 1332 if (unset_nonblock(*newsock) == -1) { 1333 close(*newsock); 1334 continue; 1335 } 1336 if (drop_connection(startups) == 1) { 1337 debug("drop connection #%d", startups); 1338 close(*newsock); 1339 continue; 1340 } 1341 if (pipe(startup_p) == -1) { 1342 close(*newsock); 1343 continue; 1344 } 1345 1346 if (rexec_flag && socketpair(AF_UNIX, 1347 SOCK_STREAM, 0, config_s) == -1) { 1348 error("reexec socketpair: %s", 1349 strerror(errno)); 1350 close(*newsock); 1351 close(startup_p[0]); 1352 close(startup_p[1]); 1353 continue; 1354 } 1355 1356 for (j = 0; j < options.max_startups; j++) 1357 if (startup_pipes[j] == -1) { 1358 startup_pipes[j] = startup_p[0]; 1359 if (maxfd < startup_p[0]) 1360 maxfd = startup_p[0]; 1361 startups++; 1362 break; 1363 } 1364 1365 /* 1366 * Got connection. Fork a child to handle it, unless 1367 * we are in debugging mode. 1368 */ 1369 if (debug_flag) { 1370 /* 1371 * In debugging mode. Close the listening 1372 * socket, and start processing the 1373 * connection without forking. 1374 */ 1375 debug("Server will not fork when running in debugging mode."); 1376 close_listen_socks(); 1377 *sock_in = *newsock; 1378 *sock_out = *newsock; 1379 close(startup_p[0]); 1380 close(startup_p[1]); 1381 startup_pipe = -1; 1382 pid = getpid(); 1383 if (rexec_flag) { 1384 send_rexec_state(config_s[0], 1385 &cfg); 1386 close(config_s[0]); 1387 } 1388 break; 1389 } 1390 1391 /* 1392 * Normal production daemon. Fork, and have 1393 * the child process the connection. The 1394 * parent continues listening. 1395 */ 1396 platform_pre_fork(); 1397 if ((pid = fork()) == 0) { 1398 /* 1399 * Child. Close the listening and 1400 * max_startup sockets. Start using 1401 * the accepted socket. Reinitialize 1402 * logging (since our pid has changed). 1403 * We break out of the loop to handle 1404 * the connection. 1405 */ 1406 platform_post_fork_child(); 1407 startup_pipe = startup_p[1]; 1408 close_startup_pipes(); 1409 close_listen_socks(); 1410 *sock_in = *newsock; 1411 *sock_out = *newsock; 1412 log_init(__progname, 1413 options.log_level, 1414 options.log_facility, 1415 log_stderr); 1416 if (rexec_flag) 1417 close(config_s[0]); 1418 break; 1419 } 1420 1421 /* Parent. Stay in the loop. */ 1422 platform_post_fork_parent(pid); 1423 if (pid < 0) 1424 error("fork: %.100s", strerror(errno)); 1425 else 1426 debug("Forked child %ld.", (long)pid); 1427 1428 close(startup_p[1]); 1429 1430 if (rexec_flag) { 1431 send_rexec_state(config_s[0], &cfg); 1432 close(config_s[0]); 1433 close(config_s[1]); 1434 } 1435 1436 /* 1437 * Mark that the key has been used (it 1438 * was "given" to the child). 1439 */ 1440 if ((options.protocol & SSH_PROTO_1) && 1441 key_used == 0) { 1442 /* Schedule server key regeneration alarm. */ 1443 signal(SIGALRM, key_regeneration_alarm); 1444 alarm(options.key_regeneration_time); 1445 key_used = 1; 1446 } 1447 1448 close(*newsock); 1449 1450 /* 1451 * Ensure that our random state differs 1452 * from that of the child 1453 */ 1454 arc4random_stir(); 1455 arc4random_buf(rnd, sizeof(rnd)); 1456 #ifdef WITH_OPENSSL 1457 RAND_seed(rnd, sizeof(rnd)); 1458 #endif 1459 explicit_bzero(rnd, sizeof(rnd)); 1460 } 1461 1462 /* child process check (or debug mode) */ 1463 if (num_listen_socks < 0) 1464 break; 1465 } 1466 } 1467 1468 1469 /* 1470 * Main program for the daemon. 1471 */ 1472 int 1473 main(int ac, char **av) 1474 { 1475 extern char *optarg; 1476 extern int optind; 1477 int r, opt, i, j, on = 1; 1478 int sock_in = -1, sock_out = -1, newsock = -1; 1479 const char *remote_ip; 1480 int remote_port; 1481 char *fp, *line, *laddr, *logfile = NULL; 1482 int config_s[2] = { -1 , -1 }; 1483 u_int n; 1484 u_int64_t ibytes, obytes; 1485 mode_t new_umask; 1486 Key *key; 1487 Key *pubkey; 1488 int keytype; 1489 Authctxt *authctxt; 1490 struct connection_info *connection_info = get_connection_info(0, 0); 1491 1492 #ifdef HAVE_SECUREWARE 1493 (void)set_auth_parameters(ac, av); 1494 #endif 1495 __progname = ssh_get_progname(av[0]); 1496 1497 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ 1498 saved_argc = ac; 1499 rexec_argc = ac; 1500 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); 1501 for (i = 0; i < ac; i++) 1502 saved_argv[i] = xstrdup(av[i]); 1503 saved_argv[i] = NULL; 1504 1505 #ifndef HAVE_SETPROCTITLE 1506 /* Prepare for later setproctitle emulation */ 1507 compat_init_setproctitle(ac, av); 1508 av = saved_argv; 1509 #endif 1510 1511 if (geteuid() == 0 && setgroups(0, NULL) == -1) 1512 debug("setgroups(): %.200s", strerror(errno)); 1513 1514 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1515 sanitise_stdfd(); 1516 1517 /* Initialize configuration options to their default values. */ 1518 initialize_server_options(&options); 1519 1520 /* Parse command-line arguments. */ 1521 while ((opt = getopt(ac, av, 1522 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) { 1523 switch (opt) { 1524 case '4': 1525 options.address_family = AF_INET; 1526 break; 1527 case '6': 1528 options.address_family = AF_INET6; 1529 break; 1530 case 'f': 1531 config_file_name = optarg; 1532 break; 1533 case 'c': 1534 if (options.num_host_cert_files >= MAX_HOSTCERTS) { 1535 fprintf(stderr, "too many host certificates.\n"); 1536 exit(1); 1537 } 1538 options.host_cert_files[options.num_host_cert_files++] = 1539 derelativise_path(optarg); 1540 break; 1541 case 'd': 1542 if (debug_flag == 0) { 1543 debug_flag = 1; 1544 options.log_level = SYSLOG_LEVEL_DEBUG1; 1545 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) 1546 options.log_level++; 1547 break; 1548 case 'D': 1549 no_daemon_flag = 1; 1550 break; 1551 case 'E': 1552 logfile = xstrdup(optarg); 1553 /* FALLTHROUGH */ 1554 case 'e': 1555 log_stderr = 1; 1556 break; 1557 case 'i': 1558 inetd_flag = 1; 1559 break; 1560 case 'r': 1561 rexec_flag = 0; 1562 break; 1563 case 'R': 1564 rexeced_flag = 1; 1565 inetd_flag = 1; 1566 break; 1567 case 'Q': 1568 /* ignored */ 1569 break; 1570 case 'q': 1571 options.log_level = SYSLOG_LEVEL_QUIET; 1572 break; 1573 case 'b': 1574 options.server_key_bits = (int)strtonum(optarg, 256, 1575 32768, NULL); 1576 break; 1577 case 'p': 1578 options.ports_from_cmdline = 1; 1579 if (options.num_ports >= MAX_PORTS) { 1580 fprintf(stderr, "too many ports.\n"); 1581 exit(1); 1582 } 1583 options.ports[options.num_ports++] = a2port(optarg); 1584 if (options.ports[options.num_ports-1] <= 0) { 1585 fprintf(stderr, "Bad port number.\n"); 1586 exit(1); 1587 } 1588 break; 1589 case 'g': 1590 if ((options.login_grace_time = convtime(optarg)) == -1) { 1591 fprintf(stderr, "Invalid login grace time.\n"); 1592 exit(1); 1593 } 1594 break; 1595 case 'k': 1596 if ((options.key_regeneration_time = convtime(optarg)) == -1) { 1597 fprintf(stderr, "Invalid key regeneration interval.\n"); 1598 exit(1); 1599 } 1600 break; 1601 case 'h': 1602 if (options.num_host_key_files >= MAX_HOSTKEYS) { 1603 fprintf(stderr, "too many host keys.\n"); 1604 exit(1); 1605 } 1606 options.host_key_files[options.num_host_key_files++] = 1607 derelativise_path(optarg); 1608 break; 1609 case 't': 1610 test_flag = 1; 1611 break; 1612 case 'T': 1613 test_flag = 2; 1614 break; 1615 case 'C': 1616 if (parse_server_match_testspec(connection_info, 1617 optarg) == -1) 1618 exit(1); 1619 break; 1620 case 'u': 1621 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL); 1622 if (utmp_len > HOST_NAME_MAX+1) { 1623 fprintf(stderr, "Invalid utmp length.\n"); 1624 exit(1); 1625 } 1626 break; 1627 case 'o': 1628 line = xstrdup(optarg); 1629 if (process_server_config_line(&options, line, 1630 "command-line", 0, NULL, NULL) != 0) 1631 exit(1); 1632 free(line); 1633 break; 1634 case '?': 1635 default: 1636 usage(); 1637 break; 1638 } 1639 } 1640 if (rexeced_flag || inetd_flag) 1641 rexec_flag = 0; 1642 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) 1643 fatal("sshd re-exec requires execution with an absolute path"); 1644 if (rexeced_flag) 1645 closefrom(REEXEC_MIN_FREE_FD); 1646 else 1647 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); 1648 1649 #ifdef WITH_OPENSSL 1650 OpenSSL_add_all_algorithms(); 1651 #endif 1652 1653 /* If requested, redirect the logs to the specified logfile. */ 1654 if (logfile != NULL) { 1655 log_redirect_stderr_to(logfile); 1656 free(logfile); 1657 } 1658 /* 1659 * Force logging to stderr until we have loaded the private host 1660 * key (unless started from inetd) 1661 */ 1662 log_init(__progname, 1663 options.log_level == SYSLOG_LEVEL_NOT_SET ? 1664 SYSLOG_LEVEL_INFO : options.log_level, 1665 options.log_facility == SYSLOG_FACILITY_NOT_SET ? 1666 SYSLOG_FACILITY_AUTH : options.log_facility, 1667 log_stderr || !inetd_flag); 1668 1669 /* 1670 * Unset KRB5CCNAME, otherwise the user's session may inherit it from 1671 * root's environment 1672 */ 1673 if (getenv("KRB5CCNAME") != NULL) 1674 (void) unsetenv("KRB5CCNAME"); 1675 1676 #ifdef _UNICOS 1677 /* Cray can define user privs drop all privs now! 1678 * Not needed on PRIV_SU systems! 1679 */ 1680 drop_cray_privs(); 1681 #endif 1682 1683 sensitive_data.server_key = NULL; 1684 sensitive_data.ssh1_host_key = NULL; 1685 sensitive_data.have_ssh1_key = 0; 1686 sensitive_data.have_ssh2_key = 0; 1687 1688 /* 1689 * If we're doing an extended config test, make sure we have all of 1690 * the parameters we need. If we're not doing an extended test, 1691 * do not silently ignore connection test params. 1692 */ 1693 if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0) 1694 fatal("user, host and addr are all required when testing " 1695 "Match configs"); 1696 if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0) 1697 fatal("Config test connection parameter (-C) provided without " 1698 "test mode (-T)"); 1699 1700 /* Fetch our configuration */ 1701 buffer_init(&cfg); 1702 if (rexeced_flag) 1703 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); 1704 else if (strcasecmp(config_file_name, "none") != 0) 1705 load_server_config(config_file_name, &cfg); 1706 1707 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, 1708 &cfg, NULL); 1709 1710 seed_rng(); 1711 1712 /* Fill in default values for those options not explicitly set. */ 1713 fill_default_server_options(&options); 1714 1715 /* challenge-response is implemented via keyboard interactive */ 1716 if (options.challenge_response_authentication) 1717 options.kbd_interactive_authentication = 1; 1718 1719 /* Check that options are sensible */ 1720 if (options.authorized_keys_command_user == NULL && 1721 (options.authorized_keys_command != NULL && 1722 strcasecmp(options.authorized_keys_command, "none") != 0)) 1723 fatal("AuthorizedKeysCommand set without " 1724 "AuthorizedKeysCommandUser"); 1725 if (options.authorized_principals_command_user == NULL && 1726 (options.authorized_principals_command != NULL && 1727 strcasecmp(options.authorized_principals_command, "none") != 0)) 1728 fatal("AuthorizedPrincipalsCommand set without " 1729 "AuthorizedPrincipalsCommandUser"); 1730 1731 /* 1732 * Check whether there is any path through configured auth methods. 1733 * Unfortunately it is not possible to verify this generally before 1734 * daemonisation in the presence of Match block, but this catches 1735 * and warns for trivial misconfigurations that could break login. 1736 */ 1737 if (options.num_auth_methods != 0) { 1738 if ((options.protocol & SSH_PROTO_1)) 1739 fatal("AuthenticationMethods is not supported with " 1740 "SSH protocol 1"); 1741 for (n = 0; n < options.num_auth_methods; n++) { 1742 if (auth2_methods_valid(options.auth_methods[n], 1743 1) == 0) 1744 break; 1745 } 1746 if (n >= options.num_auth_methods) 1747 fatal("AuthenticationMethods cannot be satisfied by " 1748 "enabled authentication methods"); 1749 } 1750 1751 /* set default channel AF */ 1752 channel_set_af(options.address_family); 1753 1754 /* Check that there are no remaining arguments. */ 1755 if (optind < ac) { 1756 fprintf(stderr, "Extra argument %s.\n", av[optind]); 1757 exit(1); 1758 } 1759 1760 debug("sshd version %s, %s", SSH_VERSION, 1761 #ifdef WITH_OPENSSL 1762 SSLeay_version(SSLEAY_VERSION) 1763 #else 1764 "without OpenSSL" 1765 #endif 1766 ); 1767 1768 /* Store privilege separation user for later use if required. */ 1769 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { 1770 if (use_privsep || options.kerberos_authentication) 1771 fatal("Privilege separation user %s does not exist", 1772 SSH_PRIVSEP_USER); 1773 } else { 1774 explicit_bzero(privsep_pw->pw_passwd, 1775 strlen(privsep_pw->pw_passwd)); 1776 privsep_pw = pwcopy(privsep_pw); 1777 free(privsep_pw->pw_passwd); 1778 privsep_pw->pw_passwd = xstrdup("*"); 1779 } 1780 endpwent(); 1781 1782 /* load host keys */ 1783 sensitive_data.host_keys = xcalloc(options.num_host_key_files, 1784 sizeof(Key *)); 1785 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files, 1786 sizeof(Key *)); 1787 1788 if (options.host_key_agent) { 1789 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME)) 1790 setenv(SSH_AUTHSOCKET_ENV_NAME, 1791 options.host_key_agent, 1); 1792 if ((r = ssh_get_authentication_socket(NULL)) == 0) 1793 have_agent = 1; 1794 else 1795 error("Could not connect to agent \"%s\": %s", 1796 options.host_key_agent, ssh_err(r)); 1797 } 1798 1799 for (i = 0; i < options.num_host_key_files; i++) { 1800 if (options.host_key_files[i] == NULL) 1801 continue; 1802 key = key_load_private(options.host_key_files[i], "", NULL); 1803 pubkey = key_load_public(options.host_key_files[i], NULL); 1804 if (pubkey == NULL && key != NULL) 1805 pubkey = key_demote(key); 1806 sensitive_data.host_keys[i] = key; 1807 sensitive_data.host_pubkeys[i] = pubkey; 1808 1809 if (key == NULL && pubkey != NULL && pubkey->type != KEY_RSA1 && 1810 have_agent) { 1811 debug("will rely on agent for hostkey %s", 1812 options.host_key_files[i]); 1813 keytype = pubkey->type; 1814 } else if (key != NULL) { 1815 keytype = key->type; 1816 } else { 1817 error("Could not load host key: %s", 1818 options.host_key_files[i]); 1819 sensitive_data.host_keys[i] = NULL; 1820 sensitive_data.host_pubkeys[i] = NULL; 1821 continue; 1822 } 1823 1824 switch (keytype) { 1825 case KEY_RSA1: 1826 sensitive_data.ssh1_host_key = key; 1827 sensitive_data.have_ssh1_key = 1; 1828 break; 1829 case KEY_RSA: 1830 case KEY_DSA: 1831 case KEY_ECDSA: 1832 case KEY_ED25519: 1833 if (have_agent || key != NULL) 1834 sensitive_data.have_ssh2_key = 1; 1835 break; 1836 } 1837 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash, 1838 SSH_FP_DEFAULT)) == NULL) 1839 fatal("sshkey_fingerprint failed"); 1840 debug("%s host key #%d: %s %s", 1841 key ? "private" : "agent", i, keytype == KEY_RSA1 ? 1842 sshkey_type(pubkey) : sshkey_ssh_name(pubkey), fp); 1843 free(fp); 1844 } 1845 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { 1846 logit("Disabling protocol version 1. Could not load host key"); 1847 options.protocol &= ~SSH_PROTO_1; 1848 } 1849 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { 1850 logit("Disabling protocol version 2. Could not load host key"); 1851 options.protocol &= ~SSH_PROTO_2; 1852 } 1853 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { 1854 logit("sshd: no hostkeys available -- exiting."); 1855 exit(1); 1856 } 1857 1858 /* 1859 * Load certificates. They are stored in an array at identical 1860 * indices to the public keys that they relate to. 1861 */ 1862 sensitive_data.host_certificates = xcalloc(options.num_host_key_files, 1863 sizeof(Key *)); 1864 for (i = 0; i < options.num_host_key_files; i++) 1865 sensitive_data.host_certificates[i] = NULL; 1866 1867 for (i = 0; i < options.num_host_cert_files; i++) { 1868 if (options.host_cert_files[i] == NULL) 1869 continue; 1870 key = key_load_public(options.host_cert_files[i], NULL); 1871 if (key == NULL) { 1872 error("Could not load host certificate: %s", 1873 options.host_cert_files[i]); 1874 continue; 1875 } 1876 if (!key_is_cert(key)) { 1877 error("Certificate file is not a certificate: %s", 1878 options.host_cert_files[i]); 1879 key_free(key); 1880 continue; 1881 } 1882 /* Find matching private key */ 1883 for (j = 0; j < options.num_host_key_files; j++) { 1884 if (key_equal_public(key, 1885 sensitive_data.host_keys[j])) { 1886 sensitive_data.host_certificates[j] = key; 1887 break; 1888 } 1889 } 1890 if (j >= options.num_host_key_files) { 1891 error("No matching private key for certificate: %s", 1892 options.host_cert_files[i]); 1893 key_free(key); 1894 continue; 1895 } 1896 sensitive_data.host_certificates[j] = key; 1897 debug("host certificate: #%d type %d %s", j, key->type, 1898 key_type(key)); 1899 } 1900 1901 #ifdef WITH_SSH1 1902 /* Check certain values for sanity. */ 1903 if (options.protocol & SSH_PROTO_1) { 1904 if (options.server_key_bits < 512 || 1905 options.server_key_bits > 32768) { 1906 fprintf(stderr, "Bad server key size.\n"); 1907 exit(1); 1908 } 1909 /* 1910 * Check that server and host key lengths differ sufficiently. This 1911 * is necessary to make double encryption work with rsaref. Oh, I 1912 * hate software patents. I dont know if this can go? Niels 1913 */ 1914 if (options.server_key_bits > 1915 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - 1916 SSH_KEY_BITS_RESERVED && options.server_key_bits < 1917 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1918 SSH_KEY_BITS_RESERVED) { 1919 options.server_key_bits = 1920 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1921 SSH_KEY_BITS_RESERVED; 1922 debug("Forcing server key to %d bits to make it differ from host key.", 1923 options.server_key_bits); 1924 } 1925 } 1926 #endif 1927 1928 if (use_privsep) { 1929 struct stat st; 1930 1931 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || 1932 (S_ISDIR(st.st_mode) == 0)) 1933 fatal("Missing privilege separation directory: %s", 1934 _PATH_PRIVSEP_CHROOT_DIR); 1935 1936 #ifdef HAVE_CYGWIN 1937 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && 1938 (st.st_uid != getuid () || 1939 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) 1940 #else 1941 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) 1942 #endif 1943 fatal("%s must be owned by root and not group or " 1944 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); 1945 } 1946 1947 if (test_flag > 1) { 1948 if (server_match_spec_complete(connection_info) == 1) 1949 parse_server_match_config(&options, connection_info); 1950 dump_config(&options); 1951 } 1952 1953 /* Configuration looks good, so exit if in test mode. */ 1954 if (test_flag) 1955 exit(0); 1956 1957 /* 1958 * Clear out any supplemental groups we may have inherited. This 1959 * prevents inadvertent creation of files with bad modes (in the 1960 * portable version at least, it's certainly possible for PAM 1961 * to create a file, and we can't control the code in every 1962 * module which might be used). 1963 */ 1964 if (setgroups(0, NULL) < 0) 1965 debug("setgroups() failed: %.200s", strerror(errno)); 1966 1967 if (rexec_flag) { 1968 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); 1969 for (i = 0; i < rexec_argc; i++) { 1970 debug("rexec_argv[%d]='%s'", i, saved_argv[i]); 1971 rexec_argv[i] = saved_argv[i]; 1972 } 1973 rexec_argv[rexec_argc] = "-R"; 1974 rexec_argv[rexec_argc + 1] = NULL; 1975 } 1976 1977 /* Ensure that umask disallows at least group and world write */ 1978 new_umask = umask(0077) | 0022; 1979 (void) umask(new_umask); 1980 1981 /* Initialize the log (it is reinitialized below in case we forked). */ 1982 if (debug_flag && (!inetd_flag || rexeced_flag)) 1983 log_stderr = 1; 1984 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1985 1986 /* 1987 * If not in debugging mode, and not started from inetd, disconnect 1988 * from the controlling terminal, and fork. The original process 1989 * exits. 1990 */ 1991 if (!(debug_flag || inetd_flag || no_daemon_flag)) { 1992 #ifdef TIOCNOTTY 1993 int fd; 1994 #endif /* TIOCNOTTY */ 1995 if (daemon(0, 0) < 0) 1996 fatal("daemon() failed: %.200s", strerror(errno)); 1997 1998 /* Disconnect from the controlling tty. */ 1999 #ifdef TIOCNOTTY 2000 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); 2001 if (fd >= 0) { 2002 (void) ioctl(fd, TIOCNOTTY, NULL); 2003 close(fd); 2004 } 2005 #endif /* TIOCNOTTY */ 2006 } 2007 /* Reinitialize the log (because of the fork above). */ 2008 log_init(__progname, options.log_level, options.log_facility, log_stderr); 2009 2010 /* Avoid killing the process in high-pressure swapping environments. */ 2011 if (!inetd_flag && madvise(NULL, 0, MADV_PROTECT) != 0) 2012 debug("madvise(): %.200s", strerror(errno)); 2013 2014 /* Chdir to the root directory so that the current disk can be 2015 unmounted if desired. */ 2016 if (chdir("/") == -1) 2017 error("chdir(\"/\"): %s", strerror(errno)); 2018 2019 /* ignore SIGPIPE */ 2020 signal(SIGPIPE, SIG_IGN); 2021 2022 /* Get a connection, either from inetd or a listening TCP socket */ 2023 if (inetd_flag) { 2024 server_accept_inetd(&sock_in, &sock_out); 2025 } else { 2026 platform_pre_listen(); 2027 server_listen(); 2028 2029 if (options.protocol & SSH_PROTO_1) 2030 generate_ephemeral_server_key(); 2031 2032 signal(SIGHUP, sighup_handler); 2033 signal(SIGCHLD, main_sigchld_handler); 2034 signal(SIGTERM, sigterm_handler); 2035 signal(SIGQUIT, sigterm_handler); 2036 2037 /* 2038 * Write out the pid file after the sigterm handler 2039 * is setup and the listen sockets are bound 2040 */ 2041 if (options.pid_file != NULL && !debug_flag) { 2042 FILE *f = fopen(options.pid_file, "w"); 2043 2044 if (f == NULL) { 2045 error("Couldn't create pid file \"%s\": %s", 2046 options.pid_file, strerror(errno)); 2047 } else { 2048 fprintf(f, "%ld\n", (long) getpid()); 2049 fclose(f); 2050 } 2051 } 2052 2053 /* Accept a connection and return in a forked child */ 2054 server_accept_loop(&sock_in, &sock_out, 2055 &newsock, config_s); 2056 } 2057 2058 /* This is the child processing a new connection. */ 2059 setproctitle("%s", "[accepted]"); 2060 2061 /* 2062 * Create a new session and process group since the 4.4BSD 2063 * setlogin() affects the entire process group. We don't 2064 * want the child to be able to affect the parent. 2065 */ 2066 #if !defined(SSHD_ACQUIRES_CTTY) 2067 /* 2068 * If setsid is called, on some platforms sshd will later acquire a 2069 * controlling terminal which will result in "could not set 2070 * controlling tty" errors. 2071 */ 2072 if (!debug_flag && !inetd_flag && setsid() < 0) 2073 error("setsid: %.100s", strerror(errno)); 2074 #endif 2075 2076 if (rexec_flag) { 2077 int fd; 2078 2079 debug("rexec start in %d out %d newsock %d pipe %d sock %d", 2080 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 2081 dup2(newsock, STDIN_FILENO); 2082 dup2(STDIN_FILENO, STDOUT_FILENO); 2083 if (startup_pipe == -1) 2084 close(REEXEC_STARTUP_PIPE_FD); 2085 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) { 2086 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); 2087 close(startup_pipe); 2088 startup_pipe = REEXEC_STARTUP_PIPE_FD; 2089 } 2090 2091 dup2(config_s[1], REEXEC_CONFIG_PASS_FD); 2092 close(config_s[1]); 2093 2094 execv(rexec_argv[0], rexec_argv); 2095 2096 /* Reexec has failed, fall back and continue */ 2097 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); 2098 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); 2099 log_init(__progname, options.log_level, 2100 options.log_facility, log_stderr); 2101 2102 /* Clean up fds */ 2103 close(REEXEC_CONFIG_PASS_FD); 2104 newsock = sock_out = sock_in = dup(STDIN_FILENO); 2105 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 2106 dup2(fd, STDIN_FILENO); 2107 dup2(fd, STDOUT_FILENO); 2108 if (fd > STDERR_FILENO) 2109 close(fd); 2110 } 2111 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", 2112 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 2113 } 2114 2115 /* Executed child processes don't need these. */ 2116 fcntl(sock_out, F_SETFD, FD_CLOEXEC); 2117 fcntl(sock_in, F_SETFD, FD_CLOEXEC); 2118 2119 /* 2120 * Disable the key regeneration alarm. We will not regenerate the 2121 * key since we are no longer in a position to give it to anyone. We 2122 * will not restart on SIGHUP since it no longer makes sense. 2123 */ 2124 alarm(0); 2125 signal(SIGALRM, SIG_DFL); 2126 signal(SIGHUP, SIG_DFL); 2127 signal(SIGTERM, SIG_DFL); 2128 signal(SIGQUIT, SIG_DFL); 2129 signal(SIGCHLD, SIG_DFL); 2130 signal(SIGINT, SIG_DFL); 2131 2132 #ifdef __FreeBSD__ 2133 /* 2134 * Initialize the resolver. This may not happen automatically 2135 * before privsep chroot(). 2136 */ 2137 if ((_res.options & RES_INIT) == 0) { 2138 debug("res_init()"); 2139 res_init(); 2140 } 2141 #ifdef GSSAPI 2142 /* 2143 * Force GSS-API to parse its configuration and load any 2144 * mechanism plugins. 2145 */ 2146 { 2147 gss_OID_set mechs; 2148 OM_uint32 minor_status; 2149 gss_indicate_mechs(&minor_status, &mechs); 2150 gss_release_oid_set(&minor_status, &mechs); 2151 } 2152 #endif 2153 #endif 2154 2155 /* 2156 * Register our connection. This turns encryption off because we do 2157 * not have a key. 2158 */ 2159 packet_set_connection(sock_in, sock_out); 2160 packet_set_server(); 2161 2162 /* Set SO_KEEPALIVE if requested. */ 2163 if (options.tcp_keep_alive && packet_connection_is_on_socket() && 2164 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) 2165 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 2166 2167 if ((remote_port = get_remote_port()) < 0) { 2168 debug("get_remote_port failed"); 2169 cleanup_exit(255); 2170 } 2171 2172 /* 2173 * We use get_canonical_hostname with usedns = 0 instead of 2174 * get_remote_ipaddr here so IP options will be checked. 2175 */ 2176 (void) get_canonical_hostname(0); 2177 /* 2178 * The rest of the code depends on the fact that 2179 * get_remote_ipaddr() caches the remote ip, even if 2180 * the socket goes away. 2181 */ 2182 remote_ip = get_remote_ipaddr(); 2183 2184 #ifdef SSH_AUDIT_EVENTS 2185 audit_connection_from(remote_ip, remote_port); 2186 #endif 2187 #ifdef LIBWRAP 2188 allow_severity = options.log_facility|LOG_INFO; 2189 deny_severity = options.log_facility|LOG_WARNING; 2190 /* Check whether logins are denied from this host. */ 2191 if (packet_connection_is_on_socket()) { 2192 struct request_info req; 2193 2194 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); 2195 fromhost(&req); 2196 2197 if (!hosts_access(&req)) { 2198 debug("Connection refused by tcp wrapper"); 2199 refuse(&req); 2200 /* NOTREACHED */ 2201 fatal("libwrap refuse returns"); 2202 } 2203 } 2204 #endif /* LIBWRAP */ 2205 2206 /* Log the connection. */ 2207 laddr = get_local_ipaddr(sock_in); 2208 verbose("Connection from %s port %d on %s port %d", 2209 remote_ip, remote_port, laddr, get_local_port()); 2210 free(laddr); 2211 2212 /* 2213 * We don't want to listen forever unless the other side 2214 * successfully authenticates itself. So we set up an alarm which is 2215 * cleared after successful authentication. A limit of zero 2216 * indicates no limit. Note that we don't set the alarm in debugging 2217 * mode; it is just annoying to have the server exit just when you 2218 * are about to discover the bug. 2219 */ 2220 signal(SIGALRM, grace_alarm_handler); 2221 if (!debug_flag) 2222 alarm(options.login_grace_time); 2223 2224 sshd_exchange_identification(sock_in, sock_out); 2225 2226 /* In inetd mode, generate ephemeral key only for proto 1 connections */ 2227 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) 2228 generate_ephemeral_server_key(); 2229 2230 packet_set_nonblocking(); 2231 2232 /* allocate authentication context */ 2233 authctxt = xcalloc(1, sizeof(*authctxt)); 2234 2235 authctxt->loginmsg = &loginmsg; 2236 2237 /* XXX global for cleanup, access from other modules */ 2238 the_authctxt = authctxt; 2239 2240 /* prepare buffer to collect messages to display to user after login */ 2241 buffer_init(&loginmsg); 2242 auth_debug_reset(); 2243 2244 if (use_privsep) { 2245 if (privsep_preauth(authctxt) == 1) 2246 goto authenticated; 2247 } else if (compat20 && have_agent) { 2248 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { 2249 error("Unable to get agent socket: %s", ssh_err(r)); 2250 have_agent = 0; 2251 } 2252 } 2253 2254 /* perform the key exchange */ 2255 /* authenticate user and start session */ 2256 if (compat20) { 2257 do_ssh2_kex(); 2258 do_authentication2(authctxt); 2259 } else { 2260 #ifdef WITH_SSH1 2261 do_ssh1_kex(); 2262 do_authentication(authctxt); 2263 #else 2264 fatal("ssh1 not supported"); 2265 #endif 2266 } 2267 /* 2268 * If we use privilege separation, the unprivileged child transfers 2269 * the current keystate and exits 2270 */ 2271 if (use_privsep) { 2272 mm_send_keystate(pmonitor); 2273 exit(0); 2274 } 2275 2276 authenticated: 2277 /* 2278 * Cancel the alarm we set to limit the time taken for 2279 * authentication. 2280 */ 2281 alarm(0); 2282 signal(SIGALRM, SIG_DFL); 2283 authctxt->authenticated = 1; 2284 if (startup_pipe != -1) { 2285 close(startup_pipe); 2286 startup_pipe = -1; 2287 } 2288 2289 #ifdef SSH_AUDIT_EVENTS 2290 audit_event(SSH_AUTH_SUCCESS); 2291 #endif 2292 2293 #ifdef GSSAPI 2294 if (options.gss_authentication) { 2295 temporarily_use_uid(authctxt->pw); 2296 ssh_gssapi_storecreds(); 2297 restore_uid(); 2298 } 2299 #endif 2300 #ifdef USE_PAM 2301 if (options.use_pam) { 2302 do_pam_setcred(1); 2303 do_pam_session(); 2304 } 2305 #endif 2306 2307 /* 2308 * In privilege separation, we fork another child and prepare 2309 * file descriptor passing. 2310 */ 2311 if (use_privsep) { 2312 privsep_postauth(authctxt); 2313 /* the monitor process [priv] will not return */ 2314 if (!compat20) 2315 destroy_sensitive_data(); 2316 } 2317 2318 packet_set_timeout(options.client_alive_interval, 2319 options.client_alive_count_max); 2320 2321 /* Try to send all our hostkeys to the client */ 2322 if (compat20) 2323 notify_hostkeys(active_state); 2324 2325 /* Start session. */ 2326 do_authenticated(authctxt); 2327 2328 /* The connection has been terminated. */ 2329 packet_get_bytes(&ibytes, &obytes); 2330 verbose("Transferred: sent %llu, received %llu bytes", 2331 (unsigned long long)obytes, (unsigned long long)ibytes); 2332 2333 verbose("Closing connection to %.500s port %d", remote_ip, remote_port); 2334 2335 #ifdef USE_PAM 2336 if (options.use_pam) 2337 finish_pam(); 2338 #endif /* USE_PAM */ 2339 2340 #ifdef SSH_AUDIT_EVENTS 2341 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); 2342 #endif 2343 2344 packet_close(); 2345 2346 if (use_privsep) 2347 mm_terminate(); 2348 2349 exit(0); 2350 } 2351 2352 #ifdef WITH_SSH1 2353 /* 2354 * Decrypt session_key_int using our private server key and private host key 2355 * (key with larger modulus first). 2356 */ 2357 int 2358 ssh1_session_key(BIGNUM *session_key_int) 2359 { 2360 int rsafail = 0; 2361 2362 if (BN_cmp(sensitive_data.server_key->rsa->n, 2363 sensitive_data.ssh1_host_key->rsa->n) > 0) { 2364 /* Server key has bigger modulus. */ 2365 if (BN_num_bits(sensitive_data.server_key->rsa->n) < 2366 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 2367 SSH_KEY_BITS_RESERVED) { 2368 fatal("do_connection: %s: " 2369 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", 2370 get_remote_ipaddr(), 2371 BN_num_bits(sensitive_data.server_key->rsa->n), 2372 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 2373 SSH_KEY_BITS_RESERVED); 2374 } 2375 if (rsa_private_decrypt(session_key_int, session_key_int, 2376 sensitive_data.server_key->rsa) != 0) 2377 rsafail++; 2378 if (rsa_private_decrypt(session_key_int, session_key_int, 2379 sensitive_data.ssh1_host_key->rsa) != 0) 2380 rsafail++; 2381 } else { 2382 /* Host key has bigger modulus (or they are equal). */ 2383 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < 2384 BN_num_bits(sensitive_data.server_key->rsa->n) + 2385 SSH_KEY_BITS_RESERVED) { 2386 fatal("do_connection: %s: " 2387 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", 2388 get_remote_ipaddr(), 2389 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 2390 BN_num_bits(sensitive_data.server_key->rsa->n), 2391 SSH_KEY_BITS_RESERVED); 2392 } 2393 if (rsa_private_decrypt(session_key_int, session_key_int, 2394 sensitive_data.ssh1_host_key->rsa) != 0) 2395 rsafail++; 2396 if (rsa_private_decrypt(session_key_int, session_key_int, 2397 sensitive_data.server_key->rsa) != 0) 2398 rsafail++; 2399 } 2400 return (rsafail); 2401 } 2402 2403 /* 2404 * SSH1 key exchange 2405 */ 2406 static void 2407 do_ssh1_kex(void) 2408 { 2409 int i, len; 2410 int rsafail = 0; 2411 BIGNUM *session_key_int, *fake_key_int, *real_key_int; 2412 u_char session_key[SSH_SESSION_KEY_LENGTH]; 2413 u_char fake_key_bytes[4096 / 8]; 2414 size_t fake_key_len; 2415 u_char cookie[8]; 2416 u_int cipher_type, auth_mask, protocol_flags; 2417 2418 /* 2419 * Generate check bytes that the client must send back in the user 2420 * packet in order for it to be accepted; this is used to defy ip 2421 * spoofing attacks. Note that this only works against somebody 2422 * doing IP spoofing from a remote machine; any machine on the local 2423 * network can still see outgoing packets and catch the random 2424 * cookie. This only affects rhosts authentication, and this is one 2425 * of the reasons why it is inherently insecure. 2426 */ 2427 arc4random_buf(cookie, sizeof(cookie)); 2428 2429 /* 2430 * Send our public key. We include in the packet 64 bits of random 2431 * data that must be matched in the reply in order to prevent IP 2432 * spoofing. 2433 */ 2434 packet_start(SSH_SMSG_PUBLIC_KEY); 2435 for (i = 0; i < 8; i++) 2436 packet_put_char(cookie[i]); 2437 2438 /* Store our public server RSA key. */ 2439 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); 2440 packet_put_bignum(sensitive_data.server_key->rsa->e); 2441 packet_put_bignum(sensitive_data.server_key->rsa->n); 2442 2443 /* Store our public host RSA key. */ 2444 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 2445 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); 2446 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); 2447 2448 /* Put protocol flags. */ 2449 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); 2450 2451 /* Declare which ciphers we support. */ 2452 packet_put_int(cipher_mask_ssh1(0)); 2453 2454 /* Declare supported authentication types. */ 2455 auth_mask = 0; 2456 if (options.rhosts_rsa_authentication) 2457 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; 2458 if (options.rsa_authentication) 2459 auth_mask |= 1 << SSH_AUTH_RSA; 2460 if (options.challenge_response_authentication == 1) 2461 auth_mask |= 1 << SSH_AUTH_TIS; 2462 if (options.password_authentication) 2463 auth_mask |= 1 << SSH_AUTH_PASSWORD; 2464 packet_put_int(auth_mask); 2465 2466 /* Send the packet and wait for it to be sent. */ 2467 packet_send(); 2468 packet_write_wait(); 2469 2470 debug("Sent %d bit server key and %d bit host key.", 2471 BN_num_bits(sensitive_data.server_key->rsa->n), 2472 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 2473 2474 /* Read clients reply (cipher type and session key). */ 2475 packet_read_expect(SSH_CMSG_SESSION_KEY); 2476 2477 /* Get cipher type and check whether we accept this. */ 2478 cipher_type = packet_get_char(); 2479 2480 if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) 2481 packet_disconnect("Warning: client selects unsupported cipher."); 2482 2483 /* Get check bytes from the packet. These must match those we 2484 sent earlier with the public key packet. */ 2485 for (i = 0; i < 8; i++) 2486 if (cookie[i] != packet_get_char()) 2487 packet_disconnect("IP Spoofing check bytes do not match."); 2488 2489 debug("Encryption type: %.200s", cipher_name(cipher_type)); 2490 2491 /* Get the encrypted integer. */ 2492 if ((real_key_int = BN_new()) == NULL) 2493 fatal("do_ssh1_kex: BN_new failed"); 2494 packet_get_bignum(real_key_int); 2495 2496 protocol_flags = packet_get_int(); 2497 packet_set_protocol_flags(protocol_flags); 2498 packet_check_eom(); 2499 2500 /* Setup a fake key in case RSA decryption fails */ 2501 if ((fake_key_int = BN_new()) == NULL) 2502 fatal("do_ssh1_kex: BN_new failed"); 2503 fake_key_len = BN_num_bytes(real_key_int); 2504 if (fake_key_len > sizeof(fake_key_bytes)) 2505 fake_key_len = sizeof(fake_key_bytes); 2506 arc4random_buf(fake_key_bytes, fake_key_len); 2507 if (BN_bin2bn(fake_key_bytes, fake_key_len, fake_key_int) == NULL) 2508 fatal("do_ssh1_kex: BN_bin2bn failed"); 2509 2510 /* Decrypt real_key_int using host/server keys */ 2511 rsafail = PRIVSEP(ssh1_session_key(real_key_int)); 2512 /* If decryption failed, use the fake key. Else, the real key. */ 2513 if (rsafail) 2514 session_key_int = fake_key_int; 2515 else 2516 session_key_int = real_key_int; 2517 2518 /* 2519 * Extract session key from the decrypted integer. The key is in the 2520 * least significant 256 bits of the integer; the first byte of the 2521 * key is in the highest bits. 2522 */ 2523 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); 2524 len = BN_num_bytes(session_key_int); 2525 if (len < 0 || (u_int)len > sizeof(session_key)) { 2526 error("do_ssh1_kex: bad session key len from %s: " 2527 "session_key_int %d > sizeof(session_key) %lu", 2528 get_remote_ipaddr(), len, (u_long)sizeof(session_key)); 2529 rsafail++; 2530 } else { 2531 explicit_bzero(session_key, sizeof(session_key)); 2532 BN_bn2bin(session_key_int, 2533 session_key + sizeof(session_key) - len); 2534 2535 derive_ssh1_session_id( 2536 sensitive_data.ssh1_host_key->rsa->n, 2537 sensitive_data.server_key->rsa->n, 2538 cookie, session_id); 2539 /* 2540 * Xor the first 16 bytes of the session key with the 2541 * session id. 2542 */ 2543 for (i = 0; i < 16; i++) 2544 session_key[i] ^= session_id[i]; 2545 } 2546 2547 /* Destroy the private and public keys. No longer. */ 2548 destroy_sensitive_data(); 2549 2550 if (use_privsep) 2551 mm_ssh1_session_id(session_id); 2552 2553 /* Destroy the decrypted integer. It is no longer needed. */ 2554 BN_clear_free(real_key_int); 2555 BN_clear_free(fake_key_int); 2556 2557 /* Set the session key. From this on all communications will be encrypted. */ 2558 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); 2559 2560 /* Destroy our copy of the session key. It is no longer needed. */ 2561 explicit_bzero(session_key, sizeof(session_key)); 2562 2563 debug("Received session key; encryption turned on."); 2564 2565 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ 2566 packet_start(SSH_SMSG_SUCCESS); 2567 packet_send(); 2568 packet_write_wait(); 2569 } 2570 #endif 2571 2572 int 2573 sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen, 2574 const u_char *data, size_t dlen, u_int flag) 2575 { 2576 int r; 2577 u_int xxx_slen, xxx_dlen = dlen; 2578 2579 if (privkey) { 2580 if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen) < 0)) 2581 fatal("%s: key_sign failed", __func__); 2582 if (slen) 2583 *slen = xxx_slen; 2584 } else if (use_privsep) { 2585 if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen) < 0) 2586 fatal("%s: pubkey_sign failed", __func__); 2587 if (slen) 2588 *slen = xxx_slen; 2589 } else { 2590 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen, 2591 data, dlen, datafellows)) != 0) 2592 fatal("%s: ssh_agent_sign failed: %s", 2593 __func__, ssh_err(r)); 2594 } 2595 return 0; 2596 } 2597 2598 /* 2599 * SSH2 key exchange: diffie-hellman-group1-sha1 2600 */ 2601 static void 2602 do_ssh2_kex(void) 2603 { 2604 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER }; 2605 struct kex *kex; 2606 int r; 2607 2608 if (options.ciphers != NULL) { 2609 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 2610 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 2611 } 2612 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 2613 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 2614 myproposal[PROPOSAL_ENC_ALGS_STOC] = 2615 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 2616 2617 if (options.macs != NULL) { 2618 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 2619 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 2620 } 2621 if (options.compression == COMP_NONE) { 2622 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2623 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; 2624 } else if (options.compression == COMP_DELAYED) { 2625 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2626 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; 2627 } 2628 if (options.kex_algorithms != NULL) 2629 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 2630 2631 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 2632 myproposal[PROPOSAL_KEX_ALGS]); 2633 2634 if (options.rekey_limit || options.rekey_interval) 2635 packet_set_rekey_limits((u_int32_t)options.rekey_limit, 2636 (time_t)options.rekey_interval); 2637 2638 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal( 2639 list_hostkey_types()); 2640 2641 /* start key exchange */ 2642 if ((r = kex_setup(active_state, myproposal)) != 0) 2643 fatal("kex_setup: %s", ssh_err(r)); 2644 kex = active_state->kex; 2645 #ifdef WITH_OPENSSL 2646 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 2647 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 2648 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 2649 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 2650 # ifdef OPENSSL_HAS_ECC 2651 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 2652 # endif 2653 #endif 2654 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 2655 kex->server = 1; 2656 kex->client_version_string=client_version_string; 2657 kex->server_version_string=server_version_string; 2658 kex->load_host_public_key=&get_hostkey_public_by_type; 2659 kex->load_host_private_key=&get_hostkey_private_by_type; 2660 kex->host_key_index=&get_hostkey_index; 2661 kex->sign = sshd_hostkey_sign; 2662 2663 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state); 2664 2665 session_id2 = kex->session_id; 2666 session_id2_len = kex->session_id_len; 2667 2668 #ifdef DEBUG_KEXDH 2669 /* send 1st encrypted/maced/compressed message */ 2670 packet_start(SSH2_MSG_IGNORE); 2671 packet_put_cstring("markus"); 2672 packet_send(); 2673 packet_write_wait(); 2674 #endif 2675 debug("KEX done"); 2676 } 2677 2678 /* server specific fatal cleanup */ 2679 void 2680 cleanup_exit(int i) 2681 { 2682 if (the_authctxt) { 2683 do_cleanup(the_authctxt); 2684 if (use_privsep && privsep_is_preauth && 2685 pmonitor != NULL && pmonitor->m_pid > 1) { 2686 debug("Killing privsep child %d", pmonitor->m_pid); 2687 if (kill(pmonitor->m_pid, SIGKILL) != 0 && 2688 errno != ESRCH) 2689 error("%s: kill(%d): %s", __func__, 2690 pmonitor->m_pid, strerror(errno)); 2691 } 2692 } 2693 #ifdef SSH_AUDIT_EVENTS 2694 /* done after do_cleanup so it can cancel the PAM auth 'thread' */ 2695 if (!use_privsep || mm_is_monitor()) 2696 audit_event(SSH_CONNECTION_ABANDON); 2697 #endif 2698 _exit(i); 2699 } 2700