1 /* $OpenBSD: sshd.c,v 1.444 2015/02/20 22:17:21 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 if ((buf = sshbuf_new()) == NULL) 950 fatal("%s: sshbuf_new", __func__); 951 for (i = nkeys = 0; i < options.num_host_key_files; i++) { 952 key = get_hostkey_public_by_index(i, ssh); 953 if (key == NULL || key->type == KEY_UNSPEC || 954 key->type == KEY_RSA1 || sshkey_is_cert(key)) 955 continue; 956 fp = sshkey_fingerprint(key, options.fingerprint_hash, 957 SSH_FP_DEFAULT); 958 debug3("%s: key %d: %s %s", __func__, i, 959 sshkey_ssh_name(key), fp); 960 free(fp); 961 if (nkeys == 0) { 962 packet_start(SSH2_MSG_GLOBAL_REQUEST); 963 packet_put_cstring("hostkeys-00@openssh.com"); 964 packet_put_char(0); /* want-reply */ 965 } 966 sshbuf_reset(buf); 967 if ((r = sshkey_putb(key, buf)) != 0) 968 fatal("%s: couldn't put hostkey %d: %s", 969 __func__, i, ssh_err(r)); 970 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf)); 971 nkeys++; 972 } 973 debug3("%s: sent %d hostkeys", __func__, nkeys); 974 if (nkeys == 0) 975 fatal("%s: no hostkeys", __func__); 976 packet_send(); 977 sshbuf_free(buf); 978 } 979 980 /* 981 * returns 1 if connection should be dropped, 0 otherwise. 982 * dropping starts at connection #max_startups_begin with a probability 983 * of (max_startups_rate/100). the probability increases linearly until 984 * all connections are dropped for startups > max_startups 985 */ 986 static int 987 drop_connection(int startups) 988 { 989 int p, r; 990 991 if (startups < options.max_startups_begin) 992 return 0; 993 if (startups >= options.max_startups) 994 return 1; 995 if (options.max_startups_rate == 100) 996 return 1; 997 998 p = 100 - options.max_startups_rate; 999 p *= startups - options.max_startups_begin; 1000 p /= options.max_startups - options.max_startups_begin; 1001 p += options.max_startups_rate; 1002 r = arc4random_uniform(100); 1003 1004 debug("drop_connection: p %d, r %d", p, r); 1005 return (r < p) ? 1 : 0; 1006 } 1007 1008 static void 1009 usage(void) 1010 { 1011 if (options.version_addendum && *options.version_addendum != '\0') 1012 fprintf(stderr, "%s %s, %s\n", 1013 SSH_RELEASE, 1014 options.version_addendum, OPENSSL_VERSION); 1015 else 1016 fprintf(stderr, "%s, %s\n", 1017 SSH_RELEASE, OPENSSL_VERSION); 1018 fprintf(stderr, 1019 "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n" 1020 " [-E log_file] [-f config_file] [-g login_grace_time]\n" 1021 " [-h host_key_file] [-k key_gen_time] [-o option] [-p port]\n" 1022 " [-u len]\n" 1023 ); 1024 exit(1); 1025 } 1026 1027 static void 1028 send_rexec_state(int fd, Buffer *conf) 1029 { 1030 Buffer m; 1031 1032 debug3("%s: entering fd = %d config len %d", __func__, fd, 1033 buffer_len(conf)); 1034 1035 /* 1036 * Protocol from reexec master to child: 1037 * string configuration 1038 * u_int ephemeral_key_follows 1039 * bignum e (only if ephemeral_key_follows == 1) 1040 * bignum n " 1041 * bignum d " 1042 * bignum iqmp " 1043 * bignum p " 1044 * bignum q " 1045 * string rngseed (only if OpenSSL is not self-seeded) 1046 */ 1047 buffer_init(&m); 1048 buffer_put_cstring(&m, buffer_ptr(conf)); 1049 1050 #ifdef WITH_SSH1 1051 if (sensitive_data.server_key != NULL && 1052 sensitive_data.server_key->type == KEY_RSA1) { 1053 buffer_put_int(&m, 1); 1054 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); 1055 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); 1056 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); 1057 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); 1058 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); 1059 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); 1060 } else 1061 #endif 1062 buffer_put_int(&m, 0); 1063 1064 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 1065 rexec_send_rng_seed(&m); 1066 #endif 1067 1068 if (ssh_msg_send(fd, 0, &m) == -1) 1069 fatal("%s: ssh_msg_send failed", __func__); 1070 1071 buffer_free(&m); 1072 1073 debug3("%s: done", __func__); 1074 } 1075 1076 static void 1077 recv_rexec_state(int fd, Buffer *conf) 1078 { 1079 Buffer m; 1080 char *cp; 1081 u_int len; 1082 1083 debug3("%s: entering fd = %d", __func__, fd); 1084 1085 buffer_init(&m); 1086 1087 if (ssh_msg_recv(fd, &m) == -1) 1088 fatal("%s: ssh_msg_recv failed", __func__); 1089 if (buffer_get_char(&m) != 0) 1090 fatal("%s: rexec version mismatch", __func__); 1091 1092 cp = buffer_get_string(&m, &len); 1093 if (conf != NULL) 1094 buffer_append(conf, cp, len + 1); 1095 free(cp); 1096 1097 if (buffer_get_int(&m)) { 1098 #ifdef WITH_SSH1 1099 if (sensitive_data.server_key != NULL) 1100 key_free(sensitive_data.server_key); 1101 sensitive_data.server_key = key_new_private(KEY_RSA1); 1102 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); 1103 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); 1104 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); 1105 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); 1106 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); 1107 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); 1108 if (rsa_generate_additional_parameters( 1109 sensitive_data.server_key->rsa) != 0) 1110 fatal("%s: rsa_generate_additional_parameters " 1111 "error", __func__); 1112 #else 1113 fatal("ssh1 not supported"); 1114 #endif 1115 } 1116 1117 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 1118 rexec_recv_rng_seed(&m); 1119 #endif 1120 1121 buffer_free(&m); 1122 1123 debug3("%s: done", __func__); 1124 } 1125 1126 /* Accept a connection from inetd */ 1127 static void 1128 server_accept_inetd(int *sock_in, int *sock_out) 1129 { 1130 int fd; 1131 1132 startup_pipe = -1; 1133 if (rexeced_flag) { 1134 close(REEXEC_CONFIG_PASS_FD); 1135 *sock_in = *sock_out = dup(STDIN_FILENO); 1136 if (!debug_flag) { 1137 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); 1138 close(REEXEC_STARTUP_PIPE_FD); 1139 } 1140 } else { 1141 *sock_in = dup(STDIN_FILENO); 1142 *sock_out = dup(STDOUT_FILENO); 1143 } 1144 /* 1145 * We intentionally do not close the descriptors 0, 1, and 2 1146 * as our code for setting the descriptors won't work if 1147 * ttyfd happens to be one of those. 1148 */ 1149 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1150 dup2(fd, STDIN_FILENO); 1151 dup2(fd, STDOUT_FILENO); 1152 if (!log_stderr) 1153 dup2(fd, STDERR_FILENO); 1154 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO)) 1155 close(fd); 1156 } 1157 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); 1158 } 1159 1160 /* 1161 * Listen for TCP connections 1162 */ 1163 static void 1164 server_listen(void) 1165 { 1166 int ret, listen_sock, on = 1; 1167 struct addrinfo *ai; 1168 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 1169 int socksize; 1170 socklen_t len; 1171 1172 for (ai = options.listen_addrs; ai; ai = ai->ai_next) { 1173 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 1174 continue; 1175 if (num_listen_socks >= MAX_LISTEN_SOCKS) 1176 fatal("Too many listen sockets. " 1177 "Enlarge MAX_LISTEN_SOCKS"); 1178 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, 1179 ntop, sizeof(ntop), strport, sizeof(strport), 1180 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { 1181 error("getnameinfo failed: %.100s", 1182 ssh_gai_strerror(ret)); 1183 continue; 1184 } 1185 /* Create socket for listening. */ 1186 listen_sock = socket(ai->ai_family, ai->ai_socktype, 1187 ai->ai_protocol); 1188 if (listen_sock < 0) { 1189 /* kernel may not support ipv6 */ 1190 verbose("socket: %.100s", strerror(errno)); 1191 continue; 1192 } 1193 if (set_nonblock(listen_sock) == -1) { 1194 close(listen_sock); 1195 continue; 1196 } 1197 /* 1198 * Set socket options. 1199 * Allow local port reuse in TIME_WAIT. 1200 */ 1201 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, 1202 &on, sizeof(on)) == -1) 1203 error("setsockopt SO_REUSEADDR: %s", strerror(errno)); 1204 1205 /* Only communicate in IPv6 over AF_INET6 sockets. */ 1206 if (ai->ai_family == AF_INET6) 1207 sock_set_v6only(listen_sock); 1208 1209 debug("Bind to port %s on %s.", strport, ntop); 1210 1211 len = sizeof(socksize); 1212 getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, &socksize, &len); 1213 debug("Server TCP RWIN socket size: %d", socksize); 1214 1215 /* Bind the socket to the desired port. */ 1216 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1217 error("Bind to port %s on %s failed: %.200s.", 1218 strport, ntop, strerror(errno)); 1219 close(listen_sock); 1220 continue; 1221 } 1222 listen_socks[num_listen_socks] = listen_sock; 1223 num_listen_socks++; 1224 1225 /* Start listening on the port. */ 1226 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) 1227 fatal("listen on [%s]:%s: %.100s", 1228 ntop, strport, strerror(errno)); 1229 logit("Server listening on %s port %s.", ntop, strport); 1230 } 1231 freeaddrinfo(options.listen_addrs); 1232 1233 if (!num_listen_socks) 1234 fatal("Cannot bind any address."); 1235 } 1236 1237 /* 1238 * The main TCP accept loop. Note that, for the non-debug case, returns 1239 * from this function are in a forked subprocess. 1240 */ 1241 static void 1242 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) 1243 { 1244 fd_set *fdset; 1245 int i, j, ret, maxfd; 1246 int key_used = 0, startups = 0; 1247 int startup_p[2] = { -1 , -1 }; 1248 struct sockaddr_storage from; 1249 socklen_t fromlen; 1250 pid_t pid; 1251 u_char rnd[256]; 1252 1253 /* setup fd set for accept */ 1254 fdset = NULL; 1255 maxfd = 0; 1256 for (i = 0; i < num_listen_socks; i++) 1257 if (listen_socks[i] > maxfd) 1258 maxfd = listen_socks[i]; 1259 /* pipes connected to unauthenticated childs */ 1260 startup_pipes = xcalloc(options.max_startups, sizeof(int)); 1261 for (i = 0; i < options.max_startups; i++) 1262 startup_pipes[i] = -1; 1263 1264 /* 1265 * Stay listening for connections until the system crashes or 1266 * the daemon is killed with a signal. 1267 */ 1268 for (;;) { 1269 if (received_sighup) 1270 sighup_restart(); 1271 if (fdset != NULL) 1272 free(fdset); 1273 fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), 1274 sizeof(fd_mask)); 1275 1276 for (i = 0; i < num_listen_socks; i++) 1277 FD_SET(listen_socks[i], fdset); 1278 for (i = 0; i < options.max_startups; i++) 1279 if (startup_pipes[i] != -1) 1280 FD_SET(startup_pipes[i], fdset); 1281 1282 /* Wait in select until there is a connection. */ 1283 ret = select(maxfd+1, fdset, NULL, NULL, NULL); 1284 if (ret < 0 && errno != EINTR) 1285 error("select: %.100s", strerror(errno)); 1286 if (received_sigterm) { 1287 logit("Received signal %d; terminating.", 1288 (int) received_sigterm); 1289 close_listen_socks(); 1290 if (options.pid_file != NULL) 1291 unlink(options.pid_file); 1292 exit(received_sigterm == SIGTERM ? 0 : 255); 1293 } 1294 if (key_used && key_do_regen) { 1295 generate_ephemeral_server_key(); 1296 key_used = 0; 1297 key_do_regen = 0; 1298 } 1299 if (ret < 0) 1300 continue; 1301 1302 for (i = 0; i < options.max_startups; i++) 1303 if (startup_pipes[i] != -1 && 1304 FD_ISSET(startup_pipes[i], fdset)) { 1305 /* 1306 * the read end of the pipe is ready 1307 * if the child has closed the pipe 1308 * after successful authentication 1309 * or if the child has died 1310 */ 1311 close(startup_pipes[i]); 1312 startup_pipes[i] = -1; 1313 startups--; 1314 } 1315 for (i = 0; i < num_listen_socks; i++) { 1316 if (!FD_ISSET(listen_socks[i], fdset)) 1317 continue; 1318 fromlen = sizeof(from); 1319 *newsock = accept(listen_socks[i], 1320 (struct sockaddr *)&from, &fromlen); 1321 if (*newsock < 0) { 1322 if (errno != EINTR && errno != EWOULDBLOCK && 1323 errno != ECONNABORTED && errno != EAGAIN) 1324 error("accept: %.100s", 1325 strerror(errno)); 1326 if (errno == EMFILE || errno == ENFILE) 1327 usleep(100 * 1000); 1328 continue; 1329 } 1330 if (unset_nonblock(*newsock) == -1) { 1331 close(*newsock); 1332 continue; 1333 } 1334 if (drop_connection(startups) == 1) { 1335 debug("drop connection #%d", startups); 1336 close(*newsock); 1337 continue; 1338 } 1339 if (pipe(startup_p) == -1) { 1340 close(*newsock); 1341 continue; 1342 } 1343 1344 if (rexec_flag && socketpair(AF_UNIX, 1345 SOCK_STREAM, 0, config_s) == -1) { 1346 error("reexec socketpair: %s", 1347 strerror(errno)); 1348 close(*newsock); 1349 close(startup_p[0]); 1350 close(startup_p[1]); 1351 continue; 1352 } 1353 1354 for (j = 0; j < options.max_startups; j++) 1355 if (startup_pipes[j] == -1) { 1356 startup_pipes[j] = startup_p[0]; 1357 if (maxfd < startup_p[0]) 1358 maxfd = startup_p[0]; 1359 startups++; 1360 break; 1361 } 1362 1363 /* 1364 * Got connection. Fork a child to handle it, unless 1365 * we are in debugging mode. 1366 */ 1367 if (debug_flag) { 1368 /* 1369 * In debugging mode. Close the listening 1370 * socket, and start processing the 1371 * connection without forking. 1372 */ 1373 debug("Server will not fork when running in debugging mode."); 1374 close_listen_socks(); 1375 *sock_in = *newsock; 1376 *sock_out = *newsock; 1377 close(startup_p[0]); 1378 close(startup_p[1]); 1379 startup_pipe = -1; 1380 pid = getpid(); 1381 if (rexec_flag) { 1382 send_rexec_state(config_s[0], 1383 &cfg); 1384 close(config_s[0]); 1385 } 1386 break; 1387 } 1388 1389 /* 1390 * Normal production daemon. Fork, and have 1391 * the child process the connection. The 1392 * parent continues listening. 1393 */ 1394 platform_pre_fork(); 1395 if ((pid = fork()) == 0) { 1396 /* 1397 * Child. Close the listening and 1398 * max_startup sockets. Start using 1399 * the accepted socket. Reinitialize 1400 * logging (since our pid has changed). 1401 * We break out of the loop to handle 1402 * the connection. 1403 */ 1404 platform_post_fork_child(); 1405 startup_pipe = startup_p[1]; 1406 close_startup_pipes(); 1407 close_listen_socks(); 1408 *sock_in = *newsock; 1409 *sock_out = *newsock; 1410 log_init(__progname, 1411 options.log_level, 1412 options.log_facility, 1413 log_stderr); 1414 if (rexec_flag) 1415 close(config_s[0]); 1416 break; 1417 } 1418 1419 /* Parent. Stay in the loop. */ 1420 platform_post_fork_parent(pid); 1421 if (pid < 0) 1422 error("fork: %.100s", strerror(errno)); 1423 else 1424 debug("Forked child %ld.", (long)pid); 1425 1426 close(startup_p[1]); 1427 1428 if (rexec_flag) { 1429 send_rexec_state(config_s[0], &cfg); 1430 close(config_s[0]); 1431 close(config_s[1]); 1432 } 1433 1434 /* 1435 * Mark that the key has been used (it 1436 * was "given" to the child). 1437 */ 1438 if ((options.protocol & SSH_PROTO_1) && 1439 key_used == 0) { 1440 /* Schedule server key regeneration alarm. */ 1441 signal(SIGALRM, key_regeneration_alarm); 1442 alarm(options.key_regeneration_time); 1443 key_used = 1; 1444 } 1445 1446 close(*newsock); 1447 1448 /* 1449 * Ensure that our random state differs 1450 * from that of the child 1451 */ 1452 arc4random_stir(); 1453 arc4random_buf(rnd, sizeof(rnd)); 1454 #ifdef WITH_OPENSSL 1455 RAND_seed(rnd, sizeof(rnd)); 1456 #endif 1457 explicit_bzero(rnd, sizeof(rnd)); 1458 } 1459 1460 /* child process check (or debug mode) */ 1461 if (num_listen_socks < 0) 1462 break; 1463 } 1464 } 1465 1466 1467 /* 1468 * Main program for the daemon. 1469 */ 1470 int 1471 main(int ac, char **av) 1472 { 1473 extern char *optarg; 1474 extern int optind; 1475 int r, opt, i, j, on = 1; 1476 int sock_in = -1, sock_out = -1, newsock = -1; 1477 const char *remote_ip; 1478 int remote_port; 1479 char *fp, *line, *logfile = NULL; 1480 int config_s[2] = { -1 , -1 }; 1481 u_int n; 1482 u_int64_t ibytes, obytes; 1483 mode_t new_umask; 1484 Key *key; 1485 Key *pubkey; 1486 int keytype; 1487 Authctxt *authctxt; 1488 struct connection_info *connection_info = get_connection_info(0, 0); 1489 1490 #ifdef HAVE_SECUREWARE 1491 (void)set_auth_parameters(ac, av); 1492 #endif 1493 __progname = ssh_get_progname(av[0]); 1494 1495 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ 1496 saved_argc = ac; 1497 rexec_argc = ac; 1498 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); 1499 for (i = 0; i < ac; i++) 1500 saved_argv[i] = xstrdup(av[i]); 1501 saved_argv[i] = NULL; 1502 1503 #ifndef HAVE_SETPROCTITLE 1504 /* Prepare for later setproctitle emulation */ 1505 compat_init_setproctitle(ac, av); 1506 av = saved_argv; 1507 #endif 1508 1509 if (geteuid() == 0 && setgroups(0, NULL) == -1) 1510 debug("setgroups(): %.200s", strerror(errno)); 1511 1512 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1513 sanitise_stdfd(); 1514 1515 /* Initialize configuration options to their default values. */ 1516 initialize_server_options(&options); 1517 1518 /* Parse command-line arguments. */ 1519 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:C:dDeE:iqrtQRT46")) != -1) { 1520 switch (opt) { 1521 case '4': 1522 options.address_family = AF_INET; 1523 break; 1524 case '6': 1525 options.address_family = AF_INET6; 1526 break; 1527 case 'f': 1528 config_file_name = optarg; 1529 break; 1530 case 'c': 1531 if (options.num_host_cert_files >= MAX_HOSTCERTS) { 1532 fprintf(stderr, "too many host certificates.\n"); 1533 exit(1); 1534 } 1535 options.host_cert_files[options.num_host_cert_files++] = 1536 derelativise_path(optarg); 1537 break; 1538 case 'd': 1539 if (debug_flag == 0) { 1540 debug_flag = 1; 1541 options.log_level = SYSLOG_LEVEL_DEBUG1; 1542 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) 1543 options.log_level++; 1544 break; 1545 case 'D': 1546 no_daemon_flag = 1; 1547 break; 1548 case 'E': 1549 logfile = xstrdup(optarg); 1550 /* FALLTHROUGH */ 1551 case 'e': 1552 log_stderr = 1; 1553 break; 1554 case 'i': 1555 inetd_flag = 1; 1556 break; 1557 case 'r': 1558 rexec_flag = 0; 1559 break; 1560 case 'R': 1561 rexeced_flag = 1; 1562 inetd_flag = 1; 1563 break; 1564 case 'Q': 1565 /* ignored */ 1566 break; 1567 case 'q': 1568 options.log_level = SYSLOG_LEVEL_QUIET; 1569 break; 1570 case 'b': 1571 options.server_key_bits = (int)strtonum(optarg, 256, 1572 32768, NULL); 1573 break; 1574 case 'p': 1575 options.ports_from_cmdline = 1; 1576 if (options.num_ports >= MAX_PORTS) { 1577 fprintf(stderr, "too many ports.\n"); 1578 exit(1); 1579 } 1580 options.ports[options.num_ports++] = a2port(optarg); 1581 if (options.ports[options.num_ports-1] <= 0) { 1582 fprintf(stderr, "Bad port number.\n"); 1583 exit(1); 1584 } 1585 break; 1586 case 'g': 1587 if ((options.login_grace_time = convtime(optarg)) == -1) { 1588 fprintf(stderr, "Invalid login grace time.\n"); 1589 exit(1); 1590 } 1591 break; 1592 case 'k': 1593 if ((options.key_regeneration_time = convtime(optarg)) == -1) { 1594 fprintf(stderr, "Invalid key regeneration interval.\n"); 1595 exit(1); 1596 } 1597 break; 1598 case 'h': 1599 if (options.num_host_key_files >= MAX_HOSTKEYS) { 1600 fprintf(stderr, "too many host keys.\n"); 1601 exit(1); 1602 } 1603 options.host_key_files[options.num_host_key_files++] = 1604 derelativise_path(optarg); 1605 break; 1606 case 't': 1607 test_flag = 1; 1608 break; 1609 case 'T': 1610 test_flag = 2; 1611 break; 1612 case 'C': 1613 if (parse_server_match_testspec(connection_info, 1614 optarg) == -1) 1615 exit(1); 1616 break; 1617 case 'u': 1618 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL); 1619 if (utmp_len > HOST_NAME_MAX+1) { 1620 fprintf(stderr, "Invalid utmp length.\n"); 1621 exit(1); 1622 } 1623 break; 1624 case 'o': 1625 line = xstrdup(optarg); 1626 if (process_server_config_line(&options, line, 1627 "command-line", 0, NULL, NULL) != 0) 1628 exit(1); 1629 free(line); 1630 break; 1631 case '?': 1632 default: 1633 usage(); 1634 break; 1635 } 1636 } 1637 if (rexeced_flag || inetd_flag) 1638 rexec_flag = 0; 1639 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) 1640 fatal("sshd re-exec requires execution with an absolute path"); 1641 if (rexeced_flag) 1642 closefrom(REEXEC_MIN_FREE_FD); 1643 else 1644 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); 1645 1646 #ifdef WITH_OPENSSL 1647 OpenSSL_add_all_algorithms(); 1648 #endif 1649 1650 /* If requested, redirect the logs to the specified logfile. */ 1651 if (logfile != NULL) { 1652 log_redirect_stderr_to(logfile); 1653 free(logfile); 1654 } 1655 /* 1656 * Force logging to stderr until we have loaded the private host 1657 * key (unless started from inetd) 1658 */ 1659 log_init(__progname, 1660 options.log_level == SYSLOG_LEVEL_NOT_SET ? 1661 SYSLOG_LEVEL_INFO : options.log_level, 1662 options.log_facility == SYSLOG_FACILITY_NOT_SET ? 1663 SYSLOG_FACILITY_AUTH : options.log_facility, 1664 log_stderr || !inetd_flag); 1665 1666 /* 1667 * Unset KRB5CCNAME, otherwise the user's session may inherit it from 1668 * root's environment 1669 */ 1670 if (getenv("KRB5CCNAME") != NULL) 1671 (void) unsetenv("KRB5CCNAME"); 1672 1673 #ifdef _UNICOS 1674 /* Cray can define user privs drop all privs now! 1675 * Not needed on PRIV_SU systems! 1676 */ 1677 drop_cray_privs(); 1678 #endif 1679 1680 sensitive_data.server_key = NULL; 1681 sensitive_data.ssh1_host_key = NULL; 1682 sensitive_data.have_ssh1_key = 0; 1683 sensitive_data.have_ssh2_key = 0; 1684 1685 /* 1686 * If we're doing an extended config test, make sure we have all of 1687 * the parameters we need. If we're not doing an extended test, 1688 * do not silently ignore connection test params. 1689 */ 1690 if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0) 1691 fatal("user, host and addr are all required when testing " 1692 "Match configs"); 1693 if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0) 1694 fatal("Config test connection parameter (-C) provided without " 1695 "test mode (-T)"); 1696 1697 /* Fetch our configuration */ 1698 buffer_init(&cfg); 1699 if (rexeced_flag) 1700 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); 1701 else 1702 load_server_config(config_file_name, &cfg); 1703 1704 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, 1705 &cfg, NULL); 1706 1707 seed_rng(); 1708 1709 /* Fill in default values for those options not explicitly set. */ 1710 fill_default_server_options(&options); 1711 1712 /* challenge-response is implemented via keyboard interactive */ 1713 if (options.challenge_response_authentication) 1714 options.kbd_interactive_authentication = 1; 1715 1716 /* Check that options are sensible */ 1717 if (options.authorized_keys_command_user == NULL && 1718 (options.authorized_keys_command != NULL && 1719 strcasecmp(options.authorized_keys_command, "none") != 0)) 1720 fatal("AuthorizedKeysCommand set without " 1721 "AuthorizedKeysCommandUser"); 1722 1723 /* 1724 * Check whether there is any path through configured auth methods. 1725 * Unfortunately it is not possible to verify this generally before 1726 * daemonisation in the presence of Match block, but this catches 1727 * and warns for trivial misconfigurations that could break login. 1728 */ 1729 if (options.num_auth_methods != 0) { 1730 if ((options.protocol & SSH_PROTO_1)) 1731 fatal("AuthenticationMethods is not supported with " 1732 "SSH protocol 1"); 1733 for (n = 0; n < options.num_auth_methods; n++) { 1734 if (auth2_methods_valid(options.auth_methods[n], 1735 1) == 0) 1736 break; 1737 } 1738 if (n >= options.num_auth_methods) 1739 fatal("AuthenticationMethods cannot be satisfied by " 1740 "enabled authentication methods"); 1741 } 1742 1743 /* set default channel AF */ 1744 channel_set_af(options.address_family); 1745 1746 /* Check that there are no remaining arguments. */ 1747 if (optind < ac) { 1748 fprintf(stderr, "Extra argument %s.\n", av[optind]); 1749 exit(1); 1750 } 1751 1752 debug("sshd version %s, %s", SSH_VERSION, 1753 #ifdef WITH_OPENSSL 1754 SSLeay_version(SSLEAY_VERSION) 1755 #else 1756 "without OpenSSL" 1757 #endif 1758 ); 1759 1760 /* Store privilege separation user for later use if required. */ 1761 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { 1762 if (use_privsep || options.kerberos_authentication) 1763 fatal("Privilege separation user %s does not exist", 1764 SSH_PRIVSEP_USER); 1765 } else { 1766 explicit_bzero(privsep_pw->pw_passwd, 1767 strlen(privsep_pw->pw_passwd)); 1768 privsep_pw = pwcopy(privsep_pw); 1769 free(privsep_pw->pw_passwd); 1770 privsep_pw->pw_passwd = xstrdup("*"); 1771 } 1772 endpwent(); 1773 1774 /* load host keys */ 1775 sensitive_data.host_keys = xcalloc(options.num_host_key_files, 1776 sizeof(Key *)); 1777 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files, 1778 sizeof(Key *)); 1779 1780 if (options.host_key_agent) { 1781 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME)) 1782 setenv(SSH_AUTHSOCKET_ENV_NAME, 1783 options.host_key_agent, 1); 1784 if ((r = ssh_get_authentication_socket(NULL)) == 0) 1785 have_agent = 1; 1786 else 1787 error("Could not connect to agent \"%s\": %s", 1788 options.host_key_agent, ssh_err(r)); 1789 } 1790 1791 for (i = 0; i < options.num_host_key_files; i++) { 1792 if (options.host_key_files[i] == NULL) 1793 continue; 1794 key = key_load_private(options.host_key_files[i], "", NULL); 1795 pubkey = key_load_public(options.host_key_files[i], NULL); 1796 if (pubkey == NULL && key != NULL) 1797 pubkey = key_demote(key); 1798 sensitive_data.host_keys[i] = key; 1799 sensitive_data.host_pubkeys[i] = pubkey; 1800 1801 if (key == NULL && pubkey != NULL && pubkey->type != KEY_RSA1 && 1802 have_agent) { 1803 debug("will rely on agent for hostkey %s", 1804 options.host_key_files[i]); 1805 keytype = pubkey->type; 1806 } else if (key != NULL) { 1807 keytype = key->type; 1808 } else { 1809 error("Could not load host key: %s", 1810 options.host_key_files[i]); 1811 sensitive_data.host_keys[i] = NULL; 1812 sensitive_data.host_pubkeys[i] = NULL; 1813 continue; 1814 } 1815 1816 switch (keytype) { 1817 case KEY_RSA1: 1818 sensitive_data.ssh1_host_key = key; 1819 sensitive_data.have_ssh1_key = 1; 1820 break; 1821 case KEY_RSA: 1822 case KEY_DSA: 1823 case KEY_ECDSA: 1824 case KEY_ED25519: 1825 if (have_agent || key != NULL) 1826 sensitive_data.have_ssh2_key = 1; 1827 break; 1828 } 1829 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash, 1830 SSH_FP_DEFAULT)) == NULL) 1831 fatal("sshkey_fingerprint failed"); 1832 debug("%s host key #%d: %s %s", 1833 key ? "private" : "agent", i, keytype == KEY_RSA1 ? 1834 sshkey_type(pubkey) : sshkey_ssh_name(pubkey), fp); 1835 free(fp); 1836 } 1837 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { 1838 logit("Disabling protocol version 1. Could not load host key"); 1839 options.protocol &= ~SSH_PROTO_1; 1840 } 1841 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { 1842 logit("Disabling protocol version 2. Could not load host key"); 1843 options.protocol &= ~SSH_PROTO_2; 1844 } 1845 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { 1846 logit("sshd: no hostkeys available -- exiting."); 1847 exit(1); 1848 } 1849 1850 /* 1851 * Load certificates. They are stored in an array at identical 1852 * indices to the public keys that they relate to. 1853 */ 1854 sensitive_data.host_certificates = xcalloc(options.num_host_key_files, 1855 sizeof(Key *)); 1856 for (i = 0; i < options.num_host_key_files; i++) 1857 sensitive_data.host_certificates[i] = NULL; 1858 1859 for (i = 0; i < options.num_host_cert_files; i++) { 1860 if (options.host_cert_files[i] == NULL) 1861 continue; 1862 key = key_load_public(options.host_cert_files[i], NULL); 1863 if (key == NULL) { 1864 error("Could not load host certificate: %s", 1865 options.host_cert_files[i]); 1866 continue; 1867 } 1868 if (!key_is_cert(key)) { 1869 error("Certificate file is not a certificate: %s", 1870 options.host_cert_files[i]); 1871 key_free(key); 1872 continue; 1873 } 1874 /* Find matching private key */ 1875 for (j = 0; j < options.num_host_key_files; j++) { 1876 if (key_equal_public(key, 1877 sensitive_data.host_keys[j])) { 1878 sensitive_data.host_certificates[j] = key; 1879 break; 1880 } 1881 } 1882 if (j >= options.num_host_key_files) { 1883 error("No matching private key for certificate: %s", 1884 options.host_cert_files[i]); 1885 key_free(key); 1886 continue; 1887 } 1888 sensitive_data.host_certificates[j] = key; 1889 debug("host certificate: #%d type %d %s", j, key->type, 1890 key_type(key)); 1891 } 1892 1893 #ifdef WITH_SSH1 1894 /* Check certain values for sanity. */ 1895 if (options.protocol & SSH_PROTO_1) { 1896 if (options.server_key_bits < 512 || 1897 options.server_key_bits > 32768) { 1898 fprintf(stderr, "Bad server key size.\n"); 1899 exit(1); 1900 } 1901 /* 1902 * Check that server and host key lengths differ sufficiently. This 1903 * is necessary to make double encryption work with rsaref. Oh, I 1904 * hate software patents. I dont know if this can go? Niels 1905 */ 1906 if (options.server_key_bits > 1907 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - 1908 SSH_KEY_BITS_RESERVED && options.server_key_bits < 1909 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1910 SSH_KEY_BITS_RESERVED) { 1911 options.server_key_bits = 1912 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1913 SSH_KEY_BITS_RESERVED; 1914 debug("Forcing server key to %d bits to make it differ from host key.", 1915 options.server_key_bits); 1916 } 1917 } 1918 #endif 1919 1920 if (use_privsep) { 1921 struct stat st; 1922 1923 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || 1924 (S_ISDIR(st.st_mode) == 0)) 1925 fatal("Missing privilege separation directory: %s", 1926 _PATH_PRIVSEP_CHROOT_DIR); 1927 1928 #ifdef HAVE_CYGWIN 1929 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && 1930 (st.st_uid != getuid () || 1931 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) 1932 #else 1933 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) 1934 #endif 1935 fatal("%s must be owned by root and not group or " 1936 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); 1937 } 1938 1939 if (test_flag > 1) { 1940 if (server_match_spec_complete(connection_info) == 1) 1941 parse_server_match_config(&options, connection_info); 1942 dump_config(&options); 1943 } 1944 1945 /* Configuration looks good, so exit if in test mode. */ 1946 if (test_flag) 1947 exit(0); 1948 1949 /* 1950 * Clear out any supplemental groups we may have inherited. This 1951 * prevents inadvertent creation of files with bad modes (in the 1952 * portable version at least, it's certainly possible for PAM 1953 * to create a file, and we can't control the code in every 1954 * module which might be used). 1955 */ 1956 if (setgroups(0, NULL) < 0) 1957 debug("setgroups() failed: %.200s", strerror(errno)); 1958 1959 if (rexec_flag) { 1960 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); 1961 for (i = 0; i < rexec_argc; i++) { 1962 debug("rexec_argv[%d]='%s'", i, saved_argv[i]); 1963 rexec_argv[i] = saved_argv[i]; 1964 } 1965 rexec_argv[rexec_argc] = "-R"; 1966 rexec_argv[rexec_argc + 1] = NULL; 1967 } 1968 1969 /* Ensure that umask disallows at least group and world write */ 1970 new_umask = umask(0077) | 0022; 1971 (void) umask(new_umask); 1972 1973 /* Initialize the log (it is reinitialized below in case we forked). */ 1974 if (debug_flag && (!inetd_flag || rexeced_flag)) 1975 log_stderr = 1; 1976 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1977 1978 /* 1979 * If not in debugging mode, and not started from inetd, disconnect 1980 * from the controlling terminal, and fork. The original process 1981 * exits. 1982 */ 1983 if (!(debug_flag || inetd_flag || no_daemon_flag)) { 1984 #ifdef TIOCNOTTY 1985 int fd; 1986 #endif /* TIOCNOTTY */ 1987 if (daemon(0, 0) < 0) 1988 fatal("daemon() failed: %.200s", strerror(errno)); 1989 1990 /* Disconnect from the controlling tty. */ 1991 #ifdef TIOCNOTTY 1992 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); 1993 if (fd >= 0) { 1994 (void) ioctl(fd, TIOCNOTTY, NULL); 1995 close(fd); 1996 } 1997 #endif /* TIOCNOTTY */ 1998 } 1999 /* Reinitialize the log (because of the fork above). */ 2000 log_init(__progname, options.log_level, options.log_facility, log_stderr); 2001 2002 /* Avoid killing the process in high-pressure swapping environments. */ 2003 if (!inetd_flag && madvise(NULL, 0, MADV_PROTECT) != 0) 2004 debug("madvise(): %.200s", strerror(errno)); 2005 2006 /* Chdir to the root directory so that the current disk can be 2007 unmounted if desired. */ 2008 if (chdir("/") == -1) 2009 error("chdir(\"/\"): %s", strerror(errno)); 2010 2011 /* ignore SIGPIPE */ 2012 signal(SIGPIPE, SIG_IGN); 2013 2014 /* Get a connection, either from inetd or a listening TCP socket */ 2015 if (inetd_flag) { 2016 server_accept_inetd(&sock_in, &sock_out); 2017 } else { 2018 platform_pre_listen(); 2019 server_listen(); 2020 2021 if (options.protocol & SSH_PROTO_1) 2022 generate_ephemeral_server_key(); 2023 2024 signal(SIGHUP, sighup_handler); 2025 signal(SIGCHLD, main_sigchld_handler); 2026 signal(SIGTERM, sigterm_handler); 2027 signal(SIGQUIT, sigterm_handler); 2028 2029 /* 2030 * Write out the pid file after the sigterm handler 2031 * is setup and the listen sockets are bound 2032 */ 2033 if (options.pid_file != NULL && !debug_flag) { 2034 FILE *f = fopen(options.pid_file, "w"); 2035 2036 if (f == NULL) { 2037 error("Couldn't create pid file \"%s\": %s", 2038 options.pid_file, strerror(errno)); 2039 } else { 2040 fprintf(f, "%ld\n", (long) getpid()); 2041 fclose(f); 2042 } 2043 } 2044 2045 /* Accept a connection and return in a forked child */ 2046 server_accept_loop(&sock_in, &sock_out, 2047 &newsock, config_s); 2048 } 2049 2050 /* This is the child processing a new connection. */ 2051 setproctitle("%s", "[accepted]"); 2052 2053 /* 2054 * Create a new session and process group since the 4.4BSD 2055 * setlogin() affects the entire process group. We don't 2056 * want the child to be able to affect the parent. 2057 */ 2058 #if !defined(SSHD_ACQUIRES_CTTY) 2059 /* 2060 * If setsid is called, on some platforms sshd will later acquire a 2061 * controlling terminal which will result in "could not set 2062 * controlling tty" errors. 2063 */ 2064 if (!debug_flag && !inetd_flag && setsid() < 0) 2065 error("setsid: %.100s", strerror(errno)); 2066 #endif 2067 2068 if (rexec_flag) { 2069 int fd; 2070 2071 debug("rexec start in %d out %d newsock %d pipe %d sock %d", 2072 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 2073 dup2(newsock, STDIN_FILENO); 2074 dup2(STDIN_FILENO, STDOUT_FILENO); 2075 if (startup_pipe == -1) 2076 close(REEXEC_STARTUP_PIPE_FD); 2077 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) { 2078 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); 2079 close(startup_pipe); 2080 startup_pipe = REEXEC_STARTUP_PIPE_FD; 2081 } 2082 2083 dup2(config_s[1], REEXEC_CONFIG_PASS_FD); 2084 close(config_s[1]); 2085 2086 execv(rexec_argv[0], rexec_argv); 2087 2088 /* Reexec has failed, fall back and continue */ 2089 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); 2090 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); 2091 log_init(__progname, options.log_level, 2092 options.log_facility, log_stderr); 2093 2094 /* Clean up fds */ 2095 close(REEXEC_CONFIG_PASS_FD); 2096 newsock = sock_out = sock_in = dup(STDIN_FILENO); 2097 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 2098 dup2(fd, STDIN_FILENO); 2099 dup2(fd, STDOUT_FILENO); 2100 if (fd > STDERR_FILENO) 2101 close(fd); 2102 } 2103 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", 2104 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 2105 } 2106 2107 /* Executed child processes don't need these. */ 2108 fcntl(sock_out, F_SETFD, FD_CLOEXEC); 2109 fcntl(sock_in, F_SETFD, FD_CLOEXEC); 2110 2111 /* 2112 * Disable the key regeneration alarm. We will not regenerate the 2113 * key since we are no longer in a position to give it to anyone. We 2114 * will not restart on SIGHUP since it no longer makes sense. 2115 */ 2116 alarm(0); 2117 signal(SIGALRM, SIG_DFL); 2118 signal(SIGHUP, SIG_DFL); 2119 signal(SIGTERM, SIG_DFL); 2120 signal(SIGQUIT, SIG_DFL); 2121 signal(SIGCHLD, SIG_DFL); 2122 signal(SIGINT, SIG_DFL); 2123 2124 #ifdef __FreeBSD__ 2125 /* 2126 * Initialize the resolver. This may not happen automatically 2127 * before privsep chroot(). 2128 */ 2129 if ((_res.options & RES_INIT) == 0) { 2130 debug("res_init()"); 2131 res_init(); 2132 } 2133 #ifdef GSSAPI 2134 /* 2135 * Force GSS-API to parse its configuration and load any 2136 * mechanism plugins. 2137 */ 2138 { 2139 gss_OID_set mechs; 2140 OM_uint32 minor_status; 2141 gss_indicate_mechs(&minor_status, &mechs); 2142 gss_release_oid_set(&minor_status, &mechs); 2143 } 2144 #endif 2145 #endif 2146 2147 /* 2148 * Register our connection. This turns encryption off because we do 2149 * not have a key. 2150 */ 2151 packet_set_connection(sock_in, sock_out); 2152 packet_set_server(); 2153 2154 /* Set SO_KEEPALIVE if requested. */ 2155 if (options.tcp_keep_alive && packet_connection_is_on_socket() && 2156 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) 2157 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 2158 2159 if ((remote_port = get_remote_port()) < 0) { 2160 debug("get_remote_port failed"); 2161 cleanup_exit(255); 2162 } 2163 2164 /* 2165 * We use get_canonical_hostname with usedns = 0 instead of 2166 * get_remote_ipaddr here so IP options will be checked. 2167 */ 2168 (void) get_canonical_hostname(0); 2169 /* 2170 * The rest of the code depends on the fact that 2171 * get_remote_ipaddr() caches the remote ip, even if 2172 * the socket goes away. 2173 */ 2174 remote_ip = get_remote_ipaddr(); 2175 2176 #ifdef SSH_AUDIT_EVENTS 2177 audit_connection_from(remote_ip, remote_port); 2178 #endif 2179 #ifdef LIBWRAP 2180 allow_severity = options.log_facility|LOG_INFO; 2181 deny_severity = options.log_facility|LOG_WARNING; 2182 /* Check whether logins are denied from this host. */ 2183 if (packet_connection_is_on_socket()) { 2184 struct request_info req; 2185 2186 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); 2187 fromhost(&req); 2188 2189 if (!hosts_access(&req)) { 2190 debug("Connection refused by tcp wrapper"); 2191 refuse(&req); 2192 /* NOTREACHED */ 2193 fatal("libwrap refuse returns"); 2194 } 2195 } 2196 #endif /* LIBWRAP */ 2197 2198 /* Log the connection. */ 2199 verbose("Connection from %s port %d on %s port %d", 2200 remote_ip, remote_port, 2201 get_local_ipaddr(sock_in), get_local_port()); 2202 2203 /* 2204 * We don't want to listen forever unless the other side 2205 * successfully authenticates itself. So we set up an alarm which is 2206 * cleared after successful authentication. A limit of zero 2207 * indicates no limit. Note that we don't set the alarm in debugging 2208 * mode; it is just annoying to have the server exit just when you 2209 * are about to discover the bug. 2210 */ 2211 signal(SIGALRM, grace_alarm_handler); 2212 if (!debug_flag) 2213 alarm(options.login_grace_time); 2214 2215 sshd_exchange_identification(sock_in, sock_out); 2216 2217 /* In inetd mode, generate ephemeral key only for proto 1 connections */ 2218 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) 2219 generate_ephemeral_server_key(); 2220 2221 packet_set_nonblocking(); 2222 2223 /* allocate authentication context */ 2224 authctxt = xcalloc(1, sizeof(*authctxt)); 2225 2226 authctxt->loginmsg = &loginmsg; 2227 2228 /* XXX global for cleanup, access from other modules */ 2229 the_authctxt = authctxt; 2230 2231 /* prepare buffer to collect messages to display to user after login */ 2232 buffer_init(&loginmsg); 2233 auth_debug_reset(); 2234 2235 if (use_privsep) { 2236 if (privsep_preauth(authctxt) == 1) 2237 goto authenticated; 2238 } else if (compat20 && have_agent) { 2239 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { 2240 error("Unable to get agent socket: %s", ssh_err(r)); 2241 have_agent = 0; 2242 } 2243 } 2244 2245 /* perform the key exchange */ 2246 /* authenticate user and start session */ 2247 if (compat20) { 2248 do_ssh2_kex(); 2249 do_authentication2(authctxt); 2250 } else { 2251 #ifdef WITH_SSH1 2252 do_ssh1_kex(); 2253 do_authentication(authctxt); 2254 #else 2255 fatal("ssh1 not supported"); 2256 #endif 2257 } 2258 /* 2259 * If we use privilege separation, the unprivileged child transfers 2260 * the current keystate and exits 2261 */ 2262 if (use_privsep) { 2263 mm_send_keystate(pmonitor); 2264 exit(0); 2265 } 2266 2267 authenticated: 2268 /* 2269 * Cancel the alarm we set to limit the time taken for 2270 * authentication. 2271 */ 2272 alarm(0); 2273 signal(SIGALRM, SIG_DFL); 2274 authctxt->authenticated = 1; 2275 if (startup_pipe != -1) { 2276 close(startup_pipe); 2277 startup_pipe = -1; 2278 } 2279 2280 #ifdef SSH_AUDIT_EVENTS 2281 audit_event(SSH_AUTH_SUCCESS); 2282 #endif 2283 2284 #ifdef GSSAPI 2285 if (options.gss_authentication) { 2286 temporarily_use_uid(authctxt->pw); 2287 ssh_gssapi_storecreds(); 2288 restore_uid(); 2289 } 2290 #endif 2291 #ifdef USE_PAM 2292 if (options.use_pam) { 2293 do_pam_setcred(1); 2294 do_pam_session(); 2295 } 2296 #endif 2297 2298 /* 2299 * In privilege separation, we fork another child and prepare 2300 * file descriptor passing. 2301 */ 2302 if (use_privsep) { 2303 privsep_postauth(authctxt); 2304 /* the monitor process [priv] will not return */ 2305 if (!compat20) 2306 destroy_sensitive_data(); 2307 } 2308 2309 packet_set_timeout(options.client_alive_interval, 2310 options.client_alive_count_max); 2311 2312 /* Try to send all our hostkeys to the client */ 2313 if (compat20) 2314 notify_hostkeys(active_state); 2315 2316 /* Start session. */ 2317 do_authenticated(authctxt); 2318 2319 /* The connection has been terminated. */ 2320 packet_get_bytes(&ibytes, &obytes); 2321 verbose("Transferred: sent %llu, received %llu bytes", 2322 (unsigned long long)obytes, (unsigned long long)ibytes); 2323 2324 verbose("Closing connection to %.500s port %d", remote_ip, remote_port); 2325 2326 #ifdef USE_PAM 2327 if (options.use_pam) 2328 finish_pam(); 2329 #endif /* USE_PAM */ 2330 2331 #ifdef SSH_AUDIT_EVENTS 2332 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); 2333 #endif 2334 2335 packet_close(); 2336 2337 if (use_privsep) 2338 mm_terminate(); 2339 2340 exit(0); 2341 } 2342 2343 #ifdef WITH_SSH1 2344 /* 2345 * Decrypt session_key_int using our private server key and private host key 2346 * (key with larger modulus first). 2347 */ 2348 int 2349 ssh1_session_key(BIGNUM *session_key_int) 2350 { 2351 int rsafail = 0; 2352 2353 if (BN_cmp(sensitive_data.server_key->rsa->n, 2354 sensitive_data.ssh1_host_key->rsa->n) > 0) { 2355 /* Server key has bigger modulus. */ 2356 if (BN_num_bits(sensitive_data.server_key->rsa->n) < 2357 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 2358 SSH_KEY_BITS_RESERVED) { 2359 fatal("do_connection: %s: " 2360 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", 2361 get_remote_ipaddr(), 2362 BN_num_bits(sensitive_data.server_key->rsa->n), 2363 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 2364 SSH_KEY_BITS_RESERVED); 2365 } 2366 if (rsa_private_decrypt(session_key_int, session_key_int, 2367 sensitive_data.server_key->rsa) != 0) 2368 rsafail++; 2369 if (rsa_private_decrypt(session_key_int, session_key_int, 2370 sensitive_data.ssh1_host_key->rsa) != 0) 2371 rsafail++; 2372 } else { 2373 /* Host key has bigger modulus (or they are equal). */ 2374 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < 2375 BN_num_bits(sensitive_data.server_key->rsa->n) + 2376 SSH_KEY_BITS_RESERVED) { 2377 fatal("do_connection: %s: " 2378 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", 2379 get_remote_ipaddr(), 2380 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 2381 BN_num_bits(sensitive_data.server_key->rsa->n), 2382 SSH_KEY_BITS_RESERVED); 2383 } 2384 if (rsa_private_decrypt(session_key_int, session_key_int, 2385 sensitive_data.ssh1_host_key->rsa) != 0) 2386 rsafail++; 2387 if (rsa_private_decrypt(session_key_int, session_key_int, 2388 sensitive_data.server_key->rsa) != 0) 2389 rsafail++; 2390 } 2391 return (rsafail); 2392 } 2393 2394 /* 2395 * SSH1 key exchange 2396 */ 2397 static void 2398 do_ssh1_kex(void) 2399 { 2400 int i, len; 2401 int rsafail = 0; 2402 BIGNUM *session_key_int, *fake_key_int, *real_key_int; 2403 u_char session_key[SSH_SESSION_KEY_LENGTH]; 2404 u_char fake_key_bytes[4096 / 8]; 2405 size_t fake_key_len; 2406 u_char cookie[8]; 2407 u_int cipher_type, auth_mask, protocol_flags; 2408 2409 /* 2410 * Generate check bytes that the client must send back in the user 2411 * packet in order for it to be accepted; this is used to defy ip 2412 * spoofing attacks. Note that this only works against somebody 2413 * doing IP spoofing from a remote machine; any machine on the local 2414 * network can still see outgoing packets and catch the random 2415 * cookie. This only affects rhosts authentication, and this is one 2416 * of the reasons why it is inherently insecure. 2417 */ 2418 arc4random_buf(cookie, sizeof(cookie)); 2419 2420 /* 2421 * Send our public key. We include in the packet 64 bits of random 2422 * data that must be matched in the reply in order to prevent IP 2423 * spoofing. 2424 */ 2425 packet_start(SSH_SMSG_PUBLIC_KEY); 2426 for (i = 0; i < 8; i++) 2427 packet_put_char(cookie[i]); 2428 2429 /* Store our public server RSA key. */ 2430 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); 2431 packet_put_bignum(sensitive_data.server_key->rsa->e); 2432 packet_put_bignum(sensitive_data.server_key->rsa->n); 2433 2434 /* Store our public host RSA key. */ 2435 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 2436 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); 2437 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); 2438 2439 /* Put protocol flags. */ 2440 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); 2441 2442 /* Declare which ciphers we support. */ 2443 packet_put_int(cipher_mask_ssh1(0)); 2444 2445 /* Declare supported authentication types. */ 2446 auth_mask = 0; 2447 if (options.rhosts_rsa_authentication) 2448 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; 2449 if (options.rsa_authentication) 2450 auth_mask |= 1 << SSH_AUTH_RSA; 2451 if (options.challenge_response_authentication == 1) 2452 auth_mask |= 1 << SSH_AUTH_TIS; 2453 if (options.password_authentication) 2454 auth_mask |= 1 << SSH_AUTH_PASSWORD; 2455 packet_put_int(auth_mask); 2456 2457 /* Send the packet and wait for it to be sent. */ 2458 packet_send(); 2459 packet_write_wait(); 2460 2461 debug("Sent %d bit server key and %d bit host key.", 2462 BN_num_bits(sensitive_data.server_key->rsa->n), 2463 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 2464 2465 /* Read clients reply (cipher type and session key). */ 2466 packet_read_expect(SSH_CMSG_SESSION_KEY); 2467 2468 /* Get cipher type and check whether we accept this. */ 2469 cipher_type = packet_get_char(); 2470 2471 if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) 2472 packet_disconnect("Warning: client selects unsupported cipher."); 2473 2474 /* Get check bytes from the packet. These must match those we 2475 sent earlier with the public key packet. */ 2476 for (i = 0; i < 8; i++) 2477 if (cookie[i] != packet_get_char()) 2478 packet_disconnect("IP Spoofing check bytes do not match."); 2479 2480 debug("Encryption type: %.200s", cipher_name(cipher_type)); 2481 2482 /* Get the encrypted integer. */ 2483 if ((real_key_int = BN_new()) == NULL) 2484 fatal("do_ssh1_kex: BN_new failed"); 2485 packet_get_bignum(real_key_int); 2486 2487 protocol_flags = packet_get_int(); 2488 packet_set_protocol_flags(protocol_flags); 2489 packet_check_eom(); 2490 2491 /* Setup a fake key in case RSA decryption fails */ 2492 if ((fake_key_int = BN_new()) == NULL) 2493 fatal("do_ssh1_kex: BN_new failed"); 2494 fake_key_len = BN_num_bytes(real_key_int); 2495 if (fake_key_len > sizeof(fake_key_bytes)) 2496 fake_key_len = sizeof(fake_key_bytes); 2497 arc4random_buf(fake_key_bytes, fake_key_len); 2498 if (BN_bin2bn(fake_key_bytes, fake_key_len, fake_key_int) == NULL) 2499 fatal("do_ssh1_kex: BN_bin2bn failed"); 2500 2501 /* Decrypt real_key_int using host/server keys */ 2502 rsafail = PRIVSEP(ssh1_session_key(real_key_int)); 2503 /* If decryption failed, use the fake key. Else, the real key. */ 2504 if (rsafail) 2505 session_key_int = fake_key_int; 2506 else 2507 session_key_int = real_key_int; 2508 2509 /* 2510 * Extract session key from the decrypted integer. The key is in the 2511 * least significant 256 bits of the integer; the first byte of the 2512 * key is in the highest bits. 2513 */ 2514 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); 2515 len = BN_num_bytes(session_key_int); 2516 if (len < 0 || (u_int)len > sizeof(session_key)) { 2517 error("do_ssh1_kex: bad session key len from %s: " 2518 "session_key_int %d > sizeof(session_key) %lu", 2519 get_remote_ipaddr(), len, (u_long)sizeof(session_key)); 2520 rsafail++; 2521 } else { 2522 explicit_bzero(session_key, sizeof(session_key)); 2523 BN_bn2bin(session_key_int, 2524 session_key + sizeof(session_key) - len); 2525 2526 derive_ssh1_session_id( 2527 sensitive_data.ssh1_host_key->rsa->n, 2528 sensitive_data.server_key->rsa->n, 2529 cookie, session_id); 2530 /* 2531 * Xor the first 16 bytes of the session key with the 2532 * session id. 2533 */ 2534 for (i = 0; i < 16; i++) 2535 session_key[i] ^= session_id[i]; 2536 } 2537 2538 /* Destroy the private and public keys. No longer. */ 2539 destroy_sensitive_data(); 2540 2541 if (use_privsep) 2542 mm_ssh1_session_id(session_id); 2543 2544 /* Destroy the decrypted integer. It is no longer needed. */ 2545 BN_clear_free(real_key_int); 2546 BN_clear_free(fake_key_int); 2547 2548 /* Set the session key. From this on all communications will be encrypted. */ 2549 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); 2550 2551 /* Destroy our copy of the session key. It is no longer needed. */ 2552 explicit_bzero(session_key, sizeof(session_key)); 2553 2554 debug("Received session key; encryption turned on."); 2555 2556 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ 2557 packet_start(SSH_SMSG_SUCCESS); 2558 packet_send(); 2559 packet_write_wait(); 2560 } 2561 #endif 2562 2563 int 2564 sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen, 2565 const u_char *data, size_t dlen, u_int flag) 2566 { 2567 int r; 2568 u_int xxx_slen, xxx_dlen = dlen; 2569 2570 if (privkey) { 2571 if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen) < 0)) 2572 fatal("%s: key_sign failed", __func__); 2573 if (slen) 2574 *slen = xxx_slen; 2575 } else if (use_privsep) { 2576 if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen) < 0) 2577 fatal("%s: pubkey_sign failed", __func__); 2578 if (slen) 2579 *slen = xxx_slen; 2580 } else { 2581 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen, 2582 data, dlen, datafellows)) != 0) 2583 fatal("%s: ssh_agent_sign failed: %s", 2584 __func__, ssh_err(r)); 2585 } 2586 return 0; 2587 } 2588 2589 /* 2590 * SSH2 key exchange: diffie-hellman-group1-sha1 2591 */ 2592 static void 2593 do_ssh2_kex(void) 2594 { 2595 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER }; 2596 struct kex *kex; 2597 int r; 2598 2599 if (options.ciphers != NULL) { 2600 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 2601 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 2602 } 2603 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 2604 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 2605 myproposal[PROPOSAL_ENC_ALGS_STOC] = 2606 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 2607 2608 if (options.macs != NULL) { 2609 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 2610 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 2611 } 2612 if (options.compression == COMP_NONE) { 2613 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2614 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; 2615 } else if (options.compression == COMP_DELAYED) { 2616 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2617 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; 2618 } 2619 if (options.kex_algorithms != NULL) 2620 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 2621 2622 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 2623 myproposal[PROPOSAL_KEX_ALGS]); 2624 2625 if (options.rekey_limit || options.rekey_interval) 2626 packet_set_rekey_limits((u_int32_t)options.rekey_limit, 2627 (time_t)options.rekey_interval); 2628 2629 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal( 2630 list_hostkey_types()); 2631 2632 /* start key exchange */ 2633 if ((r = kex_setup(active_state, myproposal)) != 0) 2634 fatal("kex_setup: %s", ssh_err(r)); 2635 kex = active_state->kex; 2636 #ifdef WITH_OPENSSL 2637 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 2638 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 2639 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 2640 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 2641 # ifdef OPENSSL_HAS_ECC 2642 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 2643 # endif 2644 #endif 2645 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 2646 kex->server = 1; 2647 kex->client_version_string=client_version_string; 2648 kex->server_version_string=server_version_string; 2649 kex->load_host_public_key=&get_hostkey_public_by_type; 2650 kex->load_host_private_key=&get_hostkey_private_by_type; 2651 kex->host_key_index=&get_hostkey_index; 2652 kex->sign = sshd_hostkey_sign; 2653 2654 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state); 2655 2656 session_id2 = kex->session_id; 2657 session_id2_len = kex->session_id_len; 2658 2659 #ifdef DEBUG_KEXDH 2660 /* send 1st encrypted/maced/compressed message */ 2661 packet_start(SSH2_MSG_IGNORE); 2662 packet_put_cstring("markus"); 2663 packet_send(); 2664 packet_write_wait(); 2665 #endif 2666 debug("KEX done"); 2667 } 2668 2669 /* server specific fatal cleanup */ 2670 void 2671 cleanup_exit(int i) 2672 { 2673 if (the_authctxt) { 2674 do_cleanup(the_authctxt); 2675 if (use_privsep && privsep_is_preauth && 2676 pmonitor != NULL && pmonitor->m_pid > 1) { 2677 debug("Killing privsep child %d", pmonitor->m_pid); 2678 if (kill(pmonitor->m_pid, SIGKILL) != 0 && 2679 errno != ESRCH) 2680 error("%s: kill(%d): %s", __func__, 2681 pmonitor->m_pid, strerror(errno)); 2682 } 2683 } 2684 #ifdef SSH_AUDIT_EVENTS 2685 /* done after do_cleanup so it can cancel the PAM auth 'thread' */ 2686 if (!use_privsep || mm_is_monitor()) 2687 audit_event(SSH_CONNECTION_ABANDON); 2688 #endif 2689 _exit(i); 2690 } 2691