1 /* $OpenBSD: sshd.c,v 1.457 2015/07/30 00:01:34 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 "match.h" 110 #include "servconf.h" 111 #include "uidswap.h" 112 #include "compat.h" 113 #include "cipher.h" 114 #include "digest.h" 115 #include "key.h" 116 #include "kex.h" 117 #include "myproposal.h" 118 #include "authfile.h" 119 #include "pathnames.h" 120 #include "atomicio.h" 121 #include "canohost.h" 122 #include "hostfile.h" 123 #include "auth.h" 124 #include "authfd.h" 125 #include "msg.h" 126 #include "dispatch.h" 127 #include "channels.h" 128 #include "session.h" 129 #include "monitor_mm.h" 130 #include "monitor.h" 131 #ifdef GSSAPI 132 #include "ssh-gss.h" 133 #endif 134 #include "monitor_wrap.h" 135 #include "roaming.h" 136 #include "ssh-sandbox.h" 137 #include "version.h" 138 #include "ssherr.h" 139 140 #ifdef LIBWRAP 141 #include <tcpd.h> 142 #include <syslog.h> 143 int allow_severity; 144 int deny_severity; 145 #endif /* LIBWRAP */ 146 147 #ifndef O_NOCTTY 148 #define O_NOCTTY 0 149 #endif 150 151 /* Re-exec fds */ 152 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) 153 #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) 154 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) 155 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) 156 157 extern char *__progname; 158 159 /* Server configuration options. */ 160 ServerOptions options; 161 162 /* Name of the server configuration file. */ 163 char *config_file_name = _PATH_SERVER_CONFIG_FILE; 164 165 /* 166 * Debug mode flag. This can be set on the command line. If debug 167 * mode is enabled, extra debugging output will be sent to the system 168 * log, the daemon will not go to background, and will exit after processing 169 * the first connection. 170 */ 171 int debug_flag = 0; 172 173 /* Flag indicating that the daemon should only test the configuration and keys. */ 174 int test_flag = 0; 175 176 /* Flag indicating that the daemon is being started from inetd. */ 177 int inetd_flag = 0; 178 179 /* Flag indicating that sshd should not detach and become a daemon. */ 180 int no_daemon_flag = 0; 181 182 /* debug goes to stderr unless inetd_flag is set */ 183 int log_stderr = 0; 184 185 /* Saved arguments to main(). */ 186 char **saved_argv; 187 int saved_argc; 188 189 /* re-exec */ 190 int rexeced_flag = 0; 191 int rexec_flag = 1; 192 int rexec_argc = 0; 193 char **rexec_argv; 194 195 /* 196 * The sockets that the server is listening; this is used in the SIGHUP 197 * signal handler. 198 */ 199 #define MAX_LISTEN_SOCKS 16 200 int listen_socks[MAX_LISTEN_SOCKS]; 201 int num_listen_socks = 0; 202 203 /* 204 * the client's version string, passed by sshd2 in compat mode. if != NULL, 205 * sshd will skip the version-number exchange 206 */ 207 char *client_version_string = NULL; 208 char *server_version_string = NULL; 209 210 /* Daemon's agent connection */ 211 int auth_sock = -1; 212 int have_agent = 0; 213 214 /* 215 * Any really sensitive data in the application is contained in this 216 * structure. The idea is that this structure could be locked into memory so 217 * that the pages do not get written into swap. However, there are some 218 * problems. The private key contains BIGNUMs, and we do not (in principle) 219 * have access to the internals of them, and locking just the structure is 220 * not very useful. Currently, memory locking is not implemented. 221 */ 222 struct { 223 Key *server_key; /* ephemeral server key */ 224 Key *ssh1_host_key; /* ssh1 host key */ 225 Key **host_keys; /* all private host keys */ 226 Key **host_pubkeys; /* all public host keys */ 227 Key **host_certificates; /* all public host certificates */ 228 int have_ssh1_key; 229 int have_ssh2_key; 230 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; 231 } sensitive_data; 232 233 /* 234 * Flag indicating whether the RSA server key needs to be regenerated. 235 * Is set in the SIGALRM handler and cleared when the key is regenerated. 236 */ 237 static volatile sig_atomic_t key_do_regen = 0; 238 239 /* This is set to true when a signal is received. */ 240 static volatile sig_atomic_t received_sighup = 0; 241 static volatile sig_atomic_t received_sigterm = 0; 242 243 /* session identifier, used by RSA-auth */ 244 u_char session_id[16]; 245 246 /* same for ssh2 */ 247 u_char *session_id2 = NULL; 248 u_int session_id2_len = 0; 249 250 /* record remote hostname or ip */ 251 u_int utmp_len = HOST_NAME_MAX+1; 252 253 /* options.max_startup sized array of fd ints */ 254 int *startup_pipes = NULL; 255 int startup_pipe; /* in child */ 256 257 /* variables used for privilege separation */ 258 int use_privsep = -1; 259 struct monitor *pmonitor = NULL; 260 int privsep_is_preauth = 1; 261 262 /* global authentication context */ 263 Authctxt *the_authctxt = NULL; 264 265 /* sshd_config buffer */ 266 Buffer cfg; 267 268 /* message to be displayed after login */ 269 Buffer loginmsg; 270 271 /* Unprivileged user */ 272 struct passwd *privsep_pw = NULL; 273 274 /* Prototypes for various functions defined later in this file. */ 275 void destroy_sensitive_data(void); 276 void demote_sensitive_data(void); 277 278 #ifdef WITH_SSH1 279 static void do_ssh1_kex(void); 280 #endif 281 static void do_ssh2_kex(void); 282 283 /* 284 * Close all listening sockets 285 */ 286 static void 287 close_listen_socks(void) 288 { 289 int i; 290 291 for (i = 0; i < num_listen_socks; i++) 292 close(listen_socks[i]); 293 num_listen_socks = -1; 294 } 295 296 static void 297 close_startup_pipes(void) 298 { 299 int i; 300 301 if (startup_pipes) 302 for (i = 0; i < options.max_startups; i++) 303 if (startup_pipes[i] != -1) 304 close(startup_pipes[i]); 305 } 306 307 /* 308 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; 309 * the effect is to reread the configuration file (and to regenerate 310 * the server key). 311 */ 312 313 /*ARGSUSED*/ 314 static void 315 sighup_handler(int sig) 316 { 317 int save_errno = errno; 318 319 received_sighup = 1; 320 signal(SIGHUP, sighup_handler); 321 errno = save_errno; 322 } 323 324 /* 325 * Called from the main program after receiving SIGHUP. 326 * Restarts the server. 327 */ 328 static void 329 sighup_restart(void) 330 { 331 logit("Received SIGHUP; restarting."); 332 platform_pre_restart(); 333 close_listen_socks(); 334 close_startup_pipes(); 335 alarm(0); /* alarm timer persists across exec */ 336 signal(SIGHUP, SIG_IGN); /* will be restored after exec */ 337 execv(saved_argv[0], saved_argv); 338 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], 339 strerror(errno)); 340 exit(1); 341 } 342 343 /* 344 * Generic signal handler for terminating signals in the master daemon. 345 */ 346 /*ARGSUSED*/ 347 static void 348 sigterm_handler(int sig) 349 { 350 received_sigterm = sig; 351 } 352 353 /* 354 * SIGCHLD handler. This is called whenever a child dies. This will then 355 * reap any zombies left by exited children. 356 */ 357 /*ARGSUSED*/ 358 static void 359 main_sigchld_handler(int sig) 360 { 361 int save_errno = errno; 362 pid_t pid; 363 int status; 364 365 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 366 (pid < 0 && errno == EINTR)) 367 ; 368 369 signal(SIGCHLD, main_sigchld_handler); 370 errno = save_errno; 371 } 372 373 /* 374 * Signal handler for the alarm after the login grace period has expired. 375 */ 376 /*ARGSUSED*/ 377 static void 378 grace_alarm_handler(int sig) 379 { 380 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) 381 kill(pmonitor->m_pid, SIGALRM); 382 383 /* 384 * Try to kill any processes that we have spawned, E.g. authorized 385 * keys command helpers. 386 */ 387 if (getpgid(0) == getpid()) { 388 signal(SIGTERM, SIG_IGN); 389 kill(0, SIGTERM); 390 } 391 392 /* Log error and exit. */ 393 sigdie("Timeout before authentication for %s", get_remote_ipaddr()); 394 } 395 396 /* 397 * Signal handler for the key regeneration alarm. Note that this 398 * alarm only occurs in the daemon waiting for connections, and it does not 399 * do anything with the private key or random state before forking. 400 * Thus there should be no concurrency control/asynchronous execution 401 * problems. 402 */ 403 static void 404 generate_ephemeral_server_key(void) 405 { 406 verbose("Generating %s%d bit RSA key.", 407 sensitive_data.server_key ? "new " : "", options.server_key_bits); 408 if (sensitive_data.server_key != NULL) 409 key_free(sensitive_data.server_key); 410 sensitive_data.server_key = key_generate(KEY_RSA1, 411 options.server_key_bits); 412 verbose("RSA key generation complete."); 413 414 arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); 415 } 416 417 /*ARGSUSED*/ 418 static void 419 key_regeneration_alarm(int sig) 420 { 421 int save_errno = errno; 422 423 signal(SIGALRM, SIG_DFL); 424 errno = save_errno; 425 key_do_regen = 1; 426 } 427 428 static void 429 sshd_exchange_identification(int sock_in, int sock_out) 430 { 431 u_int i; 432 int mismatch; 433 int remote_major, remote_minor; 434 int major, minor; 435 char *s, *newline = "\n"; 436 char buf[256]; /* Must not be larger than remote_version. */ 437 char remote_version[256]; /* Must be at least as big as buf. */ 438 439 if ((options.protocol & SSH_PROTO_1) && 440 (options.protocol & SSH_PROTO_2)) { 441 major = PROTOCOL_MAJOR_1; 442 minor = 99; 443 } else if (options.protocol & SSH_PROTO_2) { 444 major = PROTOCOL_MAJOR_2; 445 minor = PROTOCOL_MINOR_2; 446 newline = "\r\n"; 447 } else { 448 major = PROTOCOL_MAJOR_1; 449 minor = PROTOCOL_MINOR_1; 450 } 451 452 xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s", 453 major, minor, SSH_VERSION, 454 *options.version_addendum == '\0' ? "" : " ", 455 options.version_addendum, newline); 456 457 /* Send our protocol version identification. */ 458 if (roaming_atomicio(vwrite, sock_out, server_version_string, 459 strlen(server_version_string)) 460 != strlen(server_version_string)) { 461 logit("Could not write ident string to %s", get_remote_ipaddr()); 462 cleanup_exit(255); 463 } 464 465 /* Read other sides version identification. */ 466 memset(buf, 0, sizeof(buf)); 467 for (i = 0; i < sizeof(buf) - 1; i++) { 468 if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) { 469 logit("Did not receive identification string from %s", 470 get_remote_ipaddr()); 471 cleanup_exit(255); 472 } 473 if (buf[i] == '\r') { 474 buf[i] = 0; 475 /* Kludge for F-Secure Macintosh < 1.0.2 */ 476 if (i == 12 && 477 strncmp(buf, "SSH-1.5-W1.0", 12) == 0) 478 break; 479 continue; 480 } 481 if (buf[i] == '\n') { 482 buf[i] = 0; 483 break; 484 } 485 } 486 buf[sizeof(buf) - 1] = 0; 487 client_version_string = xstrdup(buf); 488 489 /* 490 * Check that the versions match. In future this might accept 491 * several versions and set appropriate flags to handle them. 492 */ 493 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", 494 &remote_major, &remote_minor, remote_version) != 3) { 495 s = "Protocol mismatch.\n"; 496 (void) atomicio(vwrite, sock_out, s, strlen(s)); 497 logit("Bad protocol version identification '%.100s' " 498 "from %s port %d", client_version_string, 499 get_remote_ipaddr(), get_remote_port()); 500 close(sock_in); 501 close(sock_out); 502 cleanup_exit(255); 503 } 504 debug("Client protocol version %d.%d; client software version %.100s", 505 remote_major, remote_minor, remote_version); 506 507 active_state->compat = compat_datafellows(remote_version); 508 509 if ((datafellows & SSH_BUG_PROBE) != 0) { 510 logit("probed from %s with %s. Don't panic.", 511 get_remote_ipaddr(), client_version_string); 512 cleanup_exit(255); 513 } 514 if ((datafellows & SSH_BUG_SCANNER) != 0) { 515 logit("scanned from %s with %s. Don't panic.", 516 get_remote_ipaddr(), client_version_string); 517 cleanup_exit(255); 518 } 519 if ((datafellows & SSH_BUG_RSASIGMD5) != 0) { 520 logit("Client version \"%.100s\" uses unsafe RSA signature " 521 "scheme; disabling use of RSA keys", remote_version); 522 } 523 if ((datafellows & SSH_BUG_DERIVEKEY) != 0) { 524 fatal("Client version \"%.100s\" uses unsafe key agreement; " 525 "refusing connection", remote_version); 526 } 527 528 mismatch = 0; 529 switch (remote_major) { 530 case 1: 531 if (remote_minor == 99) { 532 if (options.protocol & SSH_PROTO_2) 533 enable_compat20(); 534 else 535 mismatch = 1; 536 break; 537 } 538 if (!(options.protocol & SSH_PROTO_1)) { 539 mismatch = 1; 540 break; 541 } 542 if (remote_minor < 3) { 543 packet_disconnect("Your ssh version is too old and " 544 "is no longer supported. Please install a newer version."); 545 } else if (remote_minor == 3) { 546 /* note that this disables agent-forwarding */ 547 enable_compat13(); 548 } 549 break; 550 case 2: 551 if (options.protocol & SSH_PROTO_2) { 552 enable_compat20(); 553 break; 554 } 555 /* FALLTHROUGH */ 556 default: 557 mismatch = 1; 558 break; 559 } 560 chop(server_version_string); 561 debug("Local version string %.200s", server_version_string); 562 563 if (mismatch) { 564 s = "Protocol major versions differ.\n"; 565 (void) atomicio(vwrite, sock_out, s, strlen(s)); 566 close(sock_in); 567 close(sock_out); 568 logit("Protocol major versions differ for %s: %.200s vs. %.200s", 569 get_remote_ipaddr(), 570 server_version_string, client_version_string); 571 cleanup_exit(255); 572 } 573 } 574 575 /* Destroy the host and server keys. They will no longer be needed. */ 576 void 577 destroy_sensitive_data(void) 578 { 579 int i; 580 581 if (sensitive_data.server_key) { 582 key_free(sensitive_data.server_key); 583 sensitive_data.server_key = NULL; 584 } 585 for (i = 0; i < options.num_host_key_files; i++) { 586 if (sensitive_data.host_keys[i]) { 587 key_free(sensitive_data.host_keys[i]); 588 sensitive_data.host_keys[i] = NULL; 589 } 590 if (sensitive_data.host_certificates[i]) { 591 key_free(sensitive_data.host_certificates[i]); 592 sensitive_data.host_certificates[i] = NULL; 593 } 594 } 595 sensitive_data.ssh1_host_key = NULL; 596 explicit_bzero(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); 597 } 598 599 /* Demote private to public keys for network child */ 600 void 601 demote_sensitive_data(void) 602 { 603 Key *tmp; 604 int i; 605 606 if (sensitive_data.server_key) { 607 tmp = key_demote(sensitive_data.server_key); 608 key_free(sensitive_data.server_key); 609 sensitive_data.server_key = tmp; 610 } 611 612 for (i = 0; i < options.num_host_key_files; i++) { 613 if (sensitive_data.host_keys[i]) { 614 tmp = key_demote(sensitive_data.host_keys[i]); 615 key_free(sensitive_data.host_keys[i]); 616 sensitive_data.host_keys[i] = tmp; 617 if (tmp->type == KEY_RSA1) 618 sensitive_data.ssh1_host_key = tmp; 619 } 620 /* Certs do not need demotion */ 621 } 622 623 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ 624 } 625 626 static void 627 privsep_preauth_child(void) 628 { 629 u_int32_t rnd[256]; 630 gid_t gidset[1]; 631 632 /* Enable challenge-response authentication for privilege separation */ 633 privsep_challenge_enable(); 634 635 #ifdef GSSAPI 636 /* Cache supported mechanism OIDs for later use */ 637 if (options.gss_authentication) 638 ssh_gssapi_prepare_supported_oids(); 639 #endif 640 641 arc4random_stir(); 642 arc4random_buf(rnd, sizeof(rnd)); 643 #ifdef WITH_OPENSSL 644 RAND_seed(rnd, sizeof(rnd)); 645 #endif 646 explicit_bzero(rnd, sizeof(rnd)); 647 648 /* Demote the private keys to public keys. */ 649 demote_sensitive_data(); 650 651 /* Change our root directory */ 652 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) 653 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, 654 strerror(errno)); 655 if (chdir("/") == -1) 656 fatal("chdir(\"/\"): %s", strerror(errno)); 657 658 /* Drop our privileges */ 659 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, 660 (u_int)privsep_pw->pw_gid); 661 #if 0 662 /* XXX not ready, too heavy after chroot */ 663 do_setusercontext(privsep_pw); 664 #else 665 gidset[0] = privsep_pw->pw_gid; 666 if (setgroups(1, gidset) < 0) 667 fatal("setgroups: %.100s", strerror(errno)); 668 permanently_set_uid(privsep_pw); 669 #endif 670 } 671 672 static int 673 privsep_preauth(Authctxt *authctxt) 674 { 675 int status, r; 676 pid_t pid; 677 struct ssh_sandbox *box = NULL; 678 679 /* Set up unprivileged child process to deal with network data */ 680 pmonitor = monitor_init(); 681 /* Store a pointer to the kex for later rekeying */ 682 pmonitor->m_pkex = &active_state->kex; 683 684 if (use_privsep == PRIVSEP_ON) 685 box = ssh_sandbox_init(pmonitor); 686 pid = fork(); 687 if (pid == -1) { 688 fatal("fork of unprivileged child failed"); 689 } else if (pid != 0) { 690 debug2("Network child is on pid %ld", (long)pid); 691 692 pmonitor->m_pid = pid; 693 if (have_agent) { 694 r = ssh_get_authentication_socket(&auth_sock); 695 if (r != 0) { 696 error("Could not get agent socket: %s", 697 ssh_err(r)); 698 have_agent = 0; 699 } 700 } 701 if (box != NULL) 702 ssh_sandbox_parent_preauth(box, pid); 703 monitor_child_preauth(authctxt, pmonitor); 704 705 /* Sync memory */ 706 monitor_sync(pmonitor); 707 708 /* Wait for the child's exit status */ 709 while (waitpid(pid, &status, 0) < 0) { 710 if (errno == EINTR) 711 continue; 712 pmonitor->m_pid = -1; 713 fatal("%s: waitpid: %s", __func__, strerror(errno)); 714 } 715 privsep_is_preauth = 0; 716 pmonitor->m_pid = -1; 717 if (WIFEXITED(status)) { 718 if (WEXITSTATUS(status) != 0) 719 fatal("%s: preauth child exited with status %d", 720 __func__, WEXITSTATUS(status)); 721 } else if (WIFSIGNALED(status)) 722 fatal("%s: preauth child terminated by signal %d", 723 __func__, WTERMSIG(status)); 724 if (box != NULL) 725 ssh_sandbox_parent_finish(box); 726 return 1; 727 } else { 728 /* child */ 729 close(pmonitor->m_sendfd); 730 close(pmonitor->m_log_recvfd); 731 732 /* Arrange for logging to be sent to the monitor */ 733 set_log_handler(mm_log_handler, pmonitor); 734 735 /* Demote the child */ 736 if (getuid() == 0 || geteuid() == 0) 737 privsep_preauth_child(); 738 setproctitle("%s", "[net]"); 739 if (box != NULL) 740 ssh_sandbox_child(box); 741 742 return 0; 743 } 744 } 745 746 static void 747 privsep_postauth(Authctxt *authctxt) 748 { 749 u_int32_t rnd[256]; 750 751 #ifdef DISABLE_FD_PASSING 752 if (1) { 753 #else 754 if (authctxt->pw->pw_uid == 0 || options.use_login) { 755 #endif 756 /* File descriptor passing is broken or root login */ 757 use_privsep = 0; 758 goto skip; 759 } 760 761 /* New socket pair */ 762 monitor_reinit(pmonitor); 763 764 pmonitor->m_pid = fork(); 765 if (pmonitor->m_pid == -1) 766 fatal("fork of unprivileged child failed"); 767 else if (pmonitor->m_pid != 0) { 768 verbose("User child is on pid %ld", (long)pmonitor->m_pid); 769 buffer_clear(&loginmsg); 770 monitor_child_postauth(pmonitor); 771 772 /* NEVERREACHED */ 773 exit(0); 774 } 775 776 /* child */ 777 778 close(pmonitor->m_sendfd); 779 pmonitor->m_sendfd = -1; 780 781 /* Demote the private keys to public keys. */ 782 demote_sensitive_data(); 783 784 arc4random_stir(); 785 arc4random_buf(rnd, sizeof(rnd)); 786 #ifdef WITH_OPENSSL 787 RAND_seed(rnd, sizeof(rnd)); 788 #endif 789 explicit_bzero(rnd, sizeof(rnd)); 790 791 /* Drop privileges */ 792 do_setusercontext(authctxt->pw); 793 794 skip: 795 /* It is safe now to apply the key state */ 796 monitor_apply_keystate(pmonitor); 797 798 /* 799 * Tell the packet layer that authentication was successful, since 800 * this information is not part of the key state. 801 */ 802 packet_set_authenticated(); 803 } 804 805 static char * 806 list_hostkey_types(void) 807 { 808 Buffer b; 809 const char *p; 810 char *ret; 811 int i; 812 Key *key; 813 814 buffer_init(&b); 815 for (i = 0; i < options.num_host_key_files; i++) { 816 key = sensitive_data.host_keys[i]; 817 if (key == NULL) 818 key = sensitive_data.host_pubkeys[i]; 819 if (key == NULL || key->type == KEY_RSA1) 820 continue; 821 /* Check that the key is accepted in HostkeyAlgorithms */ 822 if (match_pattern_list(sshkey_ssh_name(key), 823 options.hostkeyalgorithms, 0) != 1) { 824 debug3("%s: %s key not permitted by HostkeyAlgorithms", 825 __func__, sshkey_ssh_name(key)); 826 continue; 827 } 828 switch (key->type) { 829 case KEY_RSA: 830 case KEY_DSA: 831 case KEY_ECDSA: 832 case KEY_ED25519: 833 if (buffer_len(&b) > 0) 834 buffer_append(&b, ",", 1); 835 p = key_ssh_name(key); 836 buffer_append(&b, p, strlen(p)); 837 break; 838 } 839 /* If the private key has a cert peer, then list that too */ 840 key = sensitive_data.host_certificates[i]; 841 if (key == NULL) 842 continue; 843 switch (key->type) { 844 case KEY_RSA_CERT: 845 case KEY_DSA_CERT: 846 case KEY_ECDSA_CERT: 847 case KEY_ED25519_CERT: 848 if (buffer_len(&b) > 0) 849 buffer_append(&b, ",", 1); 850 p = key_ssh_name(key); 851 buffer_append(&b, p, strlen(p)); 852 break; 853 } 854 } 855 buffer_append(&b, "\0", 1); 856 ret = xstrdup(buffer_ptr(&b)); 857 buffer_free(&b); 858 debug("list_hostkey_types: %s", ret); 859 return ret; 860 } 861 862 static Key * 863 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh) 864 { 865 int i; 866 Key *key; 867 868 for (i = 0; i < options.num_host_key_files; i++) { 869 switch (type) { 870 case KEY_RSA_CERT: 871 case KEY_DSA_CERT: 872 case KEY_ECDSA_CERT: 873 case KEY_ED25519_CERT: 874 key = sensitive_data.host_certificates[i]; 875 break; 876 default: 877 key = sensitive_data.host_keys[i]; 878 if (key == NULL && !need_private) 879 key = sensitive_data.host_pubkeys[i]; 880 break; 881 } 882 if (key != NULL && key->type == type && 883 (key->type != KEY_ECDSA || key->ecdsa_nid == nid)) 884 return need_private ? 885 sensitive_data.host_keys[i] : key; 886 } 887 return NULL; 888 } 889 890 Key * 891 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh) 892 { 893 return get_hostkey_by_type(type, nid, 0, ssh); 894 } 895 896 Key * 897 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh) 898 { 899 return get_hostkey_by_type(type, nid, 1, ssh); 900 } 901 902 Key * 903 get_hostkey_by_index(int ind) 904 { 905 if (ind < 0 || ind >= options.num_host_key_files) 906 return (NULL); 907 return (sensitive_data.host_keys[ind]); 908 } 909 910 Key * 911 get_hostkey_public_by_index(int ind, struct ssh *ssh) 912 { 913 if (ind < 0 || ind >= options.num_host_key_files) 914 return (NULL); 915 return (sensitive_data.host_pubkeys[ind]); 916 } 917 918 int 919 get_hostkey_index(Key *key, int compare, struct ssh *ssh) 920 { 921 int i; 922 923 for (i = 0; i < options.num_host_key_files; i++) { 924 if (key_is_cert(key)) { 925 if (key == sensitive_data.host_certificates[i] || 926 (compare && sensitive_data.host_certificates[i] && 927 sshkey_equal(key, 928 sensitive_data.host_certificates[i]))) 929 return (i); 930 } else { 931 if (key == sensitive_data.host_keys[i] || 932 (compare && sensitive_data.host_keys[i] && 933 sshkey_equal(key, sensitive_data.host_keys[i]))) 934 return (i); 935 if (key == sensitive_data.host_pubkeys[i] || 936 (compare && sensitive_data.host_pubkeys[i] && 937 sshkey_equal(key, sensitive_data.host_pubkeys[i]))) 938 return (i); 939 } 940 } 941 return (-1); 942 } 943 944 /* Inform the client of all hostkeys */ 945 static void 946 notify_hostkeys(struct ssh *ssh) 947 { 948 struct sshbuf *buf; 949 struct sshkey *key; 950 int i, nkeys, r; 951 char *fp; 952 953 /* Some clients cannot cope with the hostkeys message, skip those. */ 954 if (datafellows & SSH_BUG_HOSTKEYS) 955 return; 956 957 if ((buf = sshbuf_new()) == NULL) 958 fatal("%s: sshbuf_new", __func__); 959 for (i = nkeys = 0; i < options.num_host_key_files; i++) { 960 key = get_hostkey_public_by_index(i, ssh); 961 if (key == NULL || key->type == KEY_UNSPEC || 962 key->type == KEY_RSA1 || sshkey_is_cert(key)) 963 continue; 964 fp = sshkey_fingerprint(key, options.fingerprint_hash, 965 SSH_FP_DEFAULT); 966 debug3("%s: key %d: %s %s", __func__, i, 967 sshkey_ssh_name(key), fp); 968 free(fp); 969 if (nkeys == 0) { 970 packet_start(SSH2_MSG_GLOBAL_REQUEST); 971 packet_put_cstring("hostkeys-00@openssh.com"); 972 packet_put_char(0); /* want-reply */ 973 } 974 sshbuf_reset(buf); 975 if ((r = sshkey_putb(key, buf)) != 0) 976 fatal("%s: couldn't put hostkey %d: %s", 977 __func__, i, ssh_err(r)); 978 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf)); 979 nkeys++; 980 } 981 debug3("%s: sent %d hostkeys", __func__, nkeys); 982 if (nkeys == 0) 983 fatal("%s: no hostkeys", __func__); 984 packet_send(); 985 sshbuf_free(buf); 986 } 987 988 /* 989 * returns 1 if connection should be dropped, 0 otherwise. 990 * dropping starts at connection #max_startups_begin with a probability 991 * of (max_startups_rate/100). the probability increases linearly until 992 * all connections are dropped for startups > max_startups 993 */ 994 static int 995 drop_connection(int startups) 996 { 997 int p, r; 998 999 if (startups < options.max_startups_begin) 1000 return 0; 1001 if (startups >= options.max_startups) 1002 return 1; 1003 if (options.max_startups_rate == 100) 1004 return 1; 1005 1006 p = 100 - options.max_startups_rate; 1007 p *= startups - options.max_startups_begin; 1008 p /= options.max_startups - options.max_startups_begin; 1009 p += options.max_startups_rate; 1010 r = arc4random_uniform(100); 1011 1012 debug("drop_connection: p %d, r %d", p, r); 1013 return (r < p) ? 1 : 0; 1014 } 1015 1016 static void 1017 usage(void) 1018 { 1019 if (options.version_addendum && *options.version_addendum != '\0') 1020 fprintf(stderr, "%s %s, %s\n", 1021 SSH_RELEASE, 1022 options.version_addendum, OPENSSL_VERSION); 1023 else 1024 fprintf(stderr, "%s, %s\n", 1025 SSH_RELEASE, OPENSSL_VERSION); 1026 fprintf(stderr, 1027 "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n" 1028 " [-E log_file] [-f config_file] [-g login_grace_time]\n" 1029 " [-h host_key_file] [-k key_gen_time] [-o option] [-p port]\n" 1030 " [-u len]\n" 1031 ); 1032 exit(1); 1033 } 1034 1035 static void 1036 send_rexec_state(int fd, Buffer *conf) 1037 { 1038 Buffer m; 1039 1040 debug3("%s: entering fd = %d config len %d", __func__, fd, 1041 buffer_len(conf)); 1042 1043 /* 1044 * Protocol from reexec master to child: 1045 * string configuration 1046 * u_int ephemeral_key_follows 1047 * bignum e (only if ephemeral_key_follows == 1) 1048 * bignum n " 1049 * bignum d " 1050 * bignum iqmp " 1051 * bignum p " 1052 * bignum q " 1053 * string rngseed (only if OpenSSL is not self-seeded) 1054 */ 1055 buffer_init(&m); 1056 buffer_put_cstring(&m, buffer_ptr(conf)); 1057 1058 #ifdef WITH_SSH1 1059 if (sensitive_data.server_key != NULL && 1060 sensitive_data.server_key->type == KEY_RSA1) { 1061 buffer_put_int(&m, 1); 1062 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); 1063 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); 1064 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); 1065 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); 1066 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); 1067 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); 1068 } else 1069 #endif 1070 buffer_put_int(&m, 0); 1071 1072 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 1073 rexec_send_rng_seed(&m); 1074 #endif 1075 1076 if (ssh_msg_send(fd, 0, &m) == -1) 1077 fatal("%s: ssh_msg_send failed", __func__); 1078 1079 buffer_free(&m); 1080 1081 debug3("%s: done", __func__); 1082 } 1083 1084 static void 1085 recv_rexec_state(int fd, Buffer *conf) 1086 { 1087 Buffer m; 1088 char *cp; 1089 u_int len; 1090 1091 debug3("%s: entering fd = %d", __func__, fd); 1092 1093 buffer_init(&m); 1094 1095 if (ssh_msg_recv(fd, &m) == -1) 1096 fatal("%s: ssh_msg_recv failed", __func__); 1097 if (buffer_get_char(&m) != 0) 1098 fatal("%s: rexec version mismatch", __func__); 1099 1100 cp = buffer_get_string(&m, &len); 1101 if (conf != NULL) 1102 buffer_append(conf, cp, len + 1); 1103 free(cp); 1104 1105 if (buffer_get_int(&m)) { 1106 #ifdef WITH_SSH1 1107 if (sensitive_data.server_key != NULL) 1108 key_free(sensitive_data.server_key); 1109 sensitive_data.server_key = key_new_private(KEY_RSA1); 1110 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); 1111 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); 1112 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); 1113 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); 1114 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); 1115 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); 1116 if (rsa_generate_additional_parameters( 1117 sensitive_data.server_key->rsa) != 0) 1118 fatal("%s: rsa_generate_additional_parameters " 1119 "error", __func__); 1120 #endif 1121 } 1122 1123 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 1124 rexec_recv_rng_seed(&m); 1125 #endif 1126 1127 buffer_free(&m); 1128 1129 debug3("%s: done", __func__); 1130 } 1131 1132 /* Accept a connection from inetd */ 1133 static void 1134 server_accept_inetd(int *sock_in, int *sock_out) 1135 { 1136 int fd; 1137 1138 startup_pipe = -1; 1139 if (rexeced_flag) { 1140 close(REEXEC_CONFIG_PASS_FD); 1141 *sock_in = *sock_out = dup(STDIN_FILENO); 1142 if (!debug_flag) { 1143 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); 1144 close(REEXEC_STARTUP_PIPE_FD); 1145 } 1146 } else { 1147 *sock_in = dup(STDIN_FILENO); 1148 *sock_out = dup(STDOUT_FILENO); 1149 } 1150 /* 1151 * We intentionally do not close the descriptors 0, 1, and 2 1152 * as our code for setting the descriptors won't work if 1153 * ttyfd happens to be one of those. 1154 */ 1155 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1156 dup2(fd, STDIN_FILENO); 1157 dup2(fd, STDOUT_FILENO); 1158 if (!log_stderr) 1159 dup2(fd, STDERR_FILENO); 1160 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO)) 1161 close(fd); 1162 } 1163 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); 1164 } 1165 1166 /* 1167 * Listen for TCP connections 1168 */ 1169 static void 1170 server_listen(void) 1171 { 1172 int ret, listen_sock, on = 1; 1173 struct addrinfo *ai; 1174 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 1175 int socksize; 1176 socklen_t len; 1177 1178 for (ai = options.listen_addrs; ai; ai = ai->ai_next) { 1179 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 1180 continue; 1181 if (num_listen_socks >= MAX_LISTEN_SOCKS) 1182 fatal("Too many listen sockets. " 1183 "Enlarge MAX_LISTEN_SOCKS"); 1184 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, 1185 ntop, sizeof(ntop), strport, sizeof(strport), 1186 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { 1187 error("getnameinfo failed: %.100s", 1188 ssh_gai_strerror(ret)); 1189 continue; 1190 } 1191 /* Create socket for listening. */ 1192 listen_sock = socket(ai->ai_family, ai->ai_socktype, 1193 ai->ai_protocol); 1194 if (listen_sock < 0) { 1195 /* kernel may not support ipv6 */ 1196 verbose("socket: %.100s", strerror(errno)); 1197 continue; 1198 } 1199 if (set_nonblock(listen_sock) == -1) { 1200 close(listen_sock); 1201 continue; 1202 } 1203 /* 1204 * Set socket options. 1205 * Allow local port reuse in TIME_WAIT. 1206 */ 1207 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, 1208 &on, sizeof(on)) == -1) 1209 error("setsockopt SO_REUSEADDR: %s", strerror(errno)); 1210 1211 /* Only communicate in IPv6 over AF_INET6 sockets. */ 1212 if (ai->ai_family == AF_INET6) 1213 sock_set_v6only(listen_sock); 1214 1215 debug("Bind to port %s on %s.", strport, ntop); 1216 1217 len = sizeof(socksize); 1218 getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, &socksize, &len); 1219 debug("Server TCP RWIN socket size: %d", socksize); 1220 1221 /* Bind the socket to the desired port. */ 1222 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1223 error("Bind to port %s on %s failed: %.200s.", 1224 strport, ntop, strerror(errno)); 1225 close(listen_sock); 1226 continue; 1227 } 1228 listen_socks[num_listen_socks] = listen_sock; 1229 num_listen_socks++; 1230 1231 /* Start listening on the port. */ 1232 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) 1233 fatal("listen on [%s]:%s: %.100s", 1234 ntop, strport, strerror(errno)); 1235 logit("Server listening on %s port %s.", ntop, strport); 1236 } 1237 freeaddrinfo(options.listen_addrs); 1238 1239 if (!num_listen_socks) 1240 fatal("Cannot bind any address."); 1241 } 1242 1243 /* 1244 * The main TCP accept loop. Note that, for the non-debug case, returns 1245 * from this function are in a forked subprocess. 1246 */ 1247 static void 1248 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) 1249 { 1250 fd_set *fdset; 1251 int i, j, ret, maxfd; 1252 int key_used = 0, startups = 0; 1253 int startup_p[2] = { -1 , -1 }; 1254 struct sockaddr_storage from; 1255 socklen_t fromlen; 1256 pid_t pid; 1257 u_char rnd[256]; 1258 1259 /* setup fd set for accept */ 1260 fdset = NULL; 1261 maxfd = 0; 1262 for (i = 0; i < num_listen_socks; i++) 1263 if (listen_socks[i] > maxfd) 1264 maxfd = listen_socks[i]; 1265 /* pipes connected to unauthenticated childs */ 1266 startup_pipes = xcalloc(options.max_startups, sizeof(int)); 1267 for (i = 0; i < options.max_startups; i++) 1268 startup_pipes[i] = -1; 1269 1270 /* 1271 * Stay listening for connections until the system crashes or 1272 * the daemon is killed with a signal. 1273 */ 1274 for (;;) { 1275 if (received_sighup) 1276 sighup_restart(); 1277 if (fdset != NULL) 1278 free(fdset); 1279 fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), 1280 sizeof(fd_mask)); 1281 1282 for (i = 0; i < num_listen_socks; i++) 1283 FD_SET(listen_socks[i], fdset); 1284 for (i = 0; i < options.max_startups; i++) 1285 if (startup_pipes[i] != -1) 1286 FD_SET(startup_pipes[i], fdset); 1287 1288 /* Wait in select until there is a connection. */ 1289 ret = select(maxfd+1, fdset, NULL, NULL, NULL); 1290 if (ret < 0 && errno != EINTR) 1291 error("select: %.100s", strerror(errno)); 1292 if (received_sigterm) { 1293 logit("Received signal %d; terminating.", 1294 (int) received_sigterm); 1295 close_listen_socks(); 1296 if (options.pid_file != NULL) 1297 unlink(options.pid_file); 1298 exit(received_sigterm == SIGTERM ? 0 : 255); 1299 } 1300 if (key_used && key_do_regen) { 1301 generate_ephemeral_server_key(); 1302 key_used = 0; 1303 key_do_regen = 0; 1304 } 1305 if (ret < 0) 1306 continue; 1307 1308 for (i = 0; i < options.max_startups; i++) 1309 if (startup_pipes[i] != -1 && 1310 FD_ISSET(startup_pipes[i], fdset)) { 1311 /* 1312 * the read end of the pipe is ready 1313 * if the child has closed the pipe 1314 * after successful authentication 1315 * or if the child has died 1316 */ 1317 close(startup_pipes[i]); 1318 startup_pipes[i] = -1; 1319 startups--; 1320 } 1321 for (i = 0; i < num_listen_socks; i++) { 1322 if (!FD_ISSET(listen_socks[i], fdset)) 1323 continue; 1324 fromlen = sizeof(from); 1325 *newsock = accept(listen_socks[i], 1326 (struct sockaddr *)&from, &fromlen); 1327 if (*newsock < 0) { 1328 if (errno != EINTR && errno != EWOULDBLOCK && 1329 errno != ECONNABORTED && errno != EAGAIN) 1330 error("accept: %.100s", 1331 strerror(errno)); 1332 if (errno == EMFILE || errno == ENFILE) 1333 usleep(100 * 1000); 1334 continue; 1335 } 1336 if (unset_nonblock(*newsock) == -1) { 1337 close(*newsock); 1338 continue; 1339 } 1340 if (drop_connection(startups) == 1) { 1341 debug("drop connection #%d", startups); 1342 close(*newsock); 1343 continue; 1344 } 1345 if (pipe(startup_p) == -1) { 1346 close(*newsock); 1347 continue; 1348 } 1349 1350 if (rexec_flag && socketpair(AF_UNIX, 1351 SOCK_STREAM, 0, config_s) == -1) { 1352 error("reexec socketpair: %s", 1353 strerror(errno)); 1354 close(*newsock); 1355 close(startup_p[0]); 1356 close(startup_p[1]); 1357 continue; 1358 } 1359 1360 for (j = 0; j < options.max_startups; j++) 1361 if (startup_pipes[j] == -1) { 1362 startup_pipes[j] = startup_p[0]; 1363 if (maxfd < startup_p[0]) 1364 maxfd = startup_p[0]; 1365 startups++; 1366 break; 1367 } 1368 1369 /* 1370 * Got connection. Fork a child to handle it, unless 1371 * we are in debugging mode. 1372 */ 1373 if (debug_flag) { 1374 /* 1375 * In debugging mode. Close the listening 1376 * socket, and start processing the 1377 * connection without forking. 1378 */ 1379 debug("Server will not fork when running in debugging mode."); 1380 close_listen_socks(); 1381 *sock_in = *newsock; 1382 *sock_out = *newsock; 1383 close(startup_p[0]); 1384 close(startup_p[1]); 1385 startup_pipe = -1; 1386 pid = getpid(); 1387 if (rexec_flag) { 1388 send_rexec_state(config_s[0], 1389 &cfg); 1390 close(config_s[0]); 1391 } 1392 break; 1393 } 1394 1395 /* 1396 * Normal production daemon. Fork, and have 1397 * the child process the connection. The 1398 * parent continues listening. 1399 */ 1400 platform_pre_fork(); 1401 if ((pid = fork()) == 0) { 1402 /* 1403 * Child. Close the listening and 1404 * max_startup sockets. Start using 1405 * the accepted socket. Reinitialize 1406 * logging (since our pid has changed). 1407 * We break out of the loop to handle 1408 * the connection. 1409 */ 1410 platform_post_fork_child(); 1411 startup_pipe = startup_p[1]; 1412 close_startup_pipes(); 1413 close_listen_socks(); 1414 *sock_in = *newsock; 1415 *sock_out = *newsock; 1416 log_init(__progname, 1417 options.log_level, 1418 options.log_facility, 1419 log_stderr); 1420 if (rexec_flag) 1421 close(config_s[0]); 1422 break; 1423 } 1424 1425 /* Parent. Stay in the loop. */ 1426 platform_post_fork_parent(pid); 1427 if (pid < 0) 1428 error("fork: %.100s", strerror(errno)); 1429 else 1430 debug("Forked child %ld.", (long)pid); 1431 1432 close(startup_p[1]); 1433 1434 if (rexec_flag) { 1435 send_rexec_state(config_s[0], &cfg); 1436 close(config_s[0]); 1437 close(config_s[1]); 1438 } 1439 1440 /* 1441 * Mark that the key has been used (it 1442 * was "given" to the child). 1443 */ 1444 if ((options.protocol & SSH_PROTO_1) && 1445 key_used == 0) { 1446 /* Schedule server key regeneration alarm. */ 1447 signal(SIGALRM, key_regeneration_alarm); 1448 alarm(options.key_regeneration_time); 1449 key_used = 1; 1450 } 1451 1452 close(*newsock); 1453 1454 /* 1455 * Ensure that our random state differs 1456 * from that of the child 1457 */ 1458 arc4random_stir(); 1459 arc4random_buf(rnd, sizeof(rnd)); 1460 #ifdef WITH_OPENSSL 1461 RAND_seed(rnd, sizeof(rnd)); 1462 #endif 1463 explicit_bzero(rnd, sizeof(rnd)); 1464 } 1465 1466 /* child process check (or debug mode) */ 1467 if (num_listen_socks < 0) 1468 break; 1469 } 1470 } 1471 1472 1473 /* 1474 * Main program for the daemon. 1475 */ 1476 int 1477 main(int ac, char **av) 1478 { 1479 extern char *optarg; 1480 extern int optind; 1481 int r, opt, i, j, on = 1; 1482 int sock_in = -1, sock_out = -1, newsock = -1; 1483 const char *remote_ip; 1484 int remote_port; 1485 char *fp, *line, *laddr, *logfile = NULL; 1486 int config_s[2] = { -1 , -1 }; 1487 u_int n; 1488 u_int64_t ibytes, obytes; 1489 mode_t new_umask; 1490 Key *key; 1491 Key *pubkey; 1492 int keytype; 1493 Authctxt *authctxt; 1494 struct connection_info *connection_info = get_connection_info(0, 0); 1495 1496 #ifdef HAVE_SECUREWARE 1497 (void)set_auth_parameters(ac, av); 1498 #endif 1499 __progname = ssh_get_progname(av[0]); 1500 1501 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ 1502 saved_argc = ac; 1503 rexec_argc = ac; 1504 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); 1505 for (i = 0; i < ac; i++) 1506 saved_argv[i] = xstrdup(av[i]); 1507 saved_argv[i] = NULL; 1508 1509 #ifndef HAVE_SETPROCTITLE 1510 /* Prepare for later setproctitle emulation */ 1511 compat_init_setproctitle(ac, av); 1512 av = saved_argv; 1513 #endif 1514 1515 if (geteuid() == 0 && setgroups(0, NULL) == -1) 1516 debug("setgroups(): %.200s", strerror(errno)); 1517 1518 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1519 sanitise_stdfd(); 1520 1521 /* Initialize configuration options to their default values. */ 1522 initialize_server_options(&options); 1523 1524 /* Parse command-line arguments. */ 1525 while ((opt = getopt(ac, av, 1526 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) { 1527 switch (opt) { 1528 case '4': 1529 options.address_family = AF_INET; 1530 break; 1531 case '6': 1532 options.address_family = AF_INET6; 1533 break; 1534 case 'f': 1535 config_file_name = optarg; 1536 break; 1537 case 'c': 1538 if (options.num_host_cert_files >= MAX_HOSTCERTS) { 1539 fprintf(stderr, "too many host certificates.\n"); 1540 exit(1); 1541 } 1542 options.host_cert_files[options.num_host_cert_files++] = 1543 derelativise_path(optarg); 1544 break; 1545 case 'd': 1546 if (debug_flag == 0) { 1547 debug_flag = 1; 1548 options.log_level = SYSLOG_LEVEL_DEBUG1; 1549 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) 1550 options.log_level++; 1551 break; 1552 case 'D': 1553 no_daemon_flag = 1; 1554 break; 1555 case 'E': 1556 logfile = xstrdup(optarg); 1557 /* FALLTHROUGH */ 1558 case 'e': 1559 log_stderr = 1; 1560 break; 1561 case 'i': 1562 inetd_flag = 1; 1563 break; 1564 case 'r': 1565 rexec_flag = 0; 1566 break; 1567 case 'R': 1568 rexeced_flag = 1; 1569 inetd_flag = 1; 1570 break; 1571 case 'Q': 1572 /* ignored */ 1573 break; 1574 case 'q': 1575 options.log_level = SYSLOG_LEVEL_QUIET; 1576 break; 1577 case 'b': 1578 options.server_key_bits = (int)strtonum(optarg, 256, 1579 32768, NULL); 1580 break; 1581 case 'p': 1582 options.ports_from_cmdline = 1; 1583 if (options.num_ports >= MAX_PORTS) { 1584 fprintf(stderr, "too many ports.\n"); 1585 exit(1); 1586 } 1587 options.ports[options.num_ports++] = a2port(optarg); 1588 if (options.ports[options.num_ports-1] <= 0) { 1589 fprintf(stderr, "Bad port number.\n"); 1590 exit(1); 1591 } 1592 break; 1593 case 'g': 1594 if ((options.login_grace_time = convtime(optarg)) == -1) { 1595 fprintf(stderr, "Invalid login grace time.\n"); 1596 exit(1); 1597 } 1598 break; 1599 case 'k': 1600 if ((options.key_regeneration_time = convtime(optarg)) == -1) { 1601 fprintf(stderr, "Invalid key regeneration interval.\n"); 1602 exit(1); 1603 } 1604 break; 1605 case 'h': 1606 if (options.num_host_key_files >= MAX_HOSTKEYS) { 1607 fprintf(stderr, "too many host keys.\n"); 1608 exit(1); 1609 } 1610 options.host_key_files[options.num_host_key_files++] = 1611 derelativise_path(optarg); 1612 break; 1613 case 't': 1614 test_flag = 1; 1615 break; 1616 case 'T': 1617 test_flag = 2; 1618 break; 1619 case 'C': 1620 if (parse_server_match_testspec(connection_info, 1621 optarg) == -1) 1622 exit(1); 1623 break; 1624 case 'u': 1625 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL); 1626 if (utmp_len > HOST_NAME_MAX+1) { 1627 fprintf(stderr, "Invalid utmp length.\n"); 1628 exit(1); 1629 } 1630 break; 1631 case 'o': 1632 line = xstrdup(optarg); 1633 if (process_server_config_line(&options, line, 1634 "command-line", 0, NULL, NULL) != 0) 1635 exit(1); 1636 free(line); 1637 break; 1638 case '?': 1639 default: 1640 usage(); 1641 break; 1642 } 1643 } 1644 if (rexeced_flag || inetd_flag) 1645 rexec_flag = 0; 1646 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) 1647 fatal("sshd re-exec requires execution with an absolute path"); 1648 if (rexeced_flag) 1649 closefrom(REEXEC_MIN_FREE_FD); 1650 else 1651 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); 1652 1653 #ifdef WITH_OPENSSL 1654 OpenSSL_add_all_algorithms(); 1655 #endif 1656 1657 /* If requested, redirect the logs to the specified logfile. */ 1658 if (logfile != NULL) { 1659 log_redirect_stderr_to(logfile); 1660 free(logfile); 1661 } 1662 /* 1663 * Force logging to stderr until we have loaded the private host 1664 * key (unless started from inetd) 1665 */ 1666 log_init(__progname, 1667 options.log_level == SYSLOG_LEVEL_NOT_SET ? 1668 SYSLOG_LEVEL_INFO : options.log_level, 1669 options.log_facility == SYSLOG_FACILITY_NOT_SET ? 1670 SYSLOG_FACILITY_AUTH : options.log_facility, 1671 log_stderr || !inetd_flag); 1672 1673 /* 1674 * Unset KRB5CCNAME, otherwise the user's session may inherit it from 1675 * root's environment 1676 */ 1677 if (getenv("KRB5CCNAME") != NULL) 1678 (void) unsetenv("KRB5CCNAME"); 1679 1680 #ifdef _UNICOS 1681 /* Cray can define user privs drop all privs now! 1682 * Not needed on PRIV_SU systems! 1683 */ 1684 drop_cray_privs(); 1685 #endif 1686 1687 sensitive_data.server_key = NULL; 1688 sensitive_data.ssh1_host_key = NULL; 1689 sensitive_data.have_ssh1_key = 0; 1690 sensitive_data.have_ssh2_key = 0; 1691 1692 /* 1693 * If we're doing an extended config test, make sure we have all of 1694 * the parameters we need. If we're not doing an extended test, 1695 * do not silently ignore connection test params. 1696 */ 1697 if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0) 1698 fatal("user, host and addr are all required when testing " 1699 "Match configs"); 1700 if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0) 1701 fatal("Config test connection parameter (-C) provided without " 1702 "test mode (-T)"); 1703 1704 /* Fetch our configuration */ 1705 buffer_init(&cfg); 1706 if (rexeced_flag) 1707 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); 1708 else if (strcasecmp(config_file_name, "none") != 0) 1709 load_server_config(config_file_name, &cfg); 1710 1711 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, 1712 &cfg, NULL); 1713 1714 seed_rng(); 1715 1716 /* Fill in default values for those options not explicitly set. */ 1717 fill_default_server_options(&options); 1718 1719 /* challenge-response is implemented via keyboard interactive */ 1720 if (options.challenge_response_authentication) 1721 options.kbd_interactive_authentication = 1; 1722 1723 /* Check that options are sensible */ 1724 if (options.authorized_keys_command_user == NULL && 1725 (options.authorized_keys_command != NULL && 1726 strcasecmp(options.authorized_keys_command, "none") != 0)) 1727 fatal("AuthorizedKeysCommand set without " 1728 "AuthorizedKeysCommandUser"); 1729 if (options.authorized_principals_command_user == NULL && 1730 (options.authorized_principals_command != NULL && 1731 strcasecmp(options.authorized_principals_command, "none") != 0)) 1732 fatal("AuthorizedPrincipalsCommand set without " 1733 "AuthorizedPrincipalsCommandUser"); 1734 1735 /* 1736 * Check whether there is any path through configured auth methods. 1737 * Unfortunately it is not possible to verify this generally before 1738 * daemonisation in the presence of Match block, but this catches 1739 * and warns for trivial misconfigurations that could break login. 1740 */ 1741 if (options.num_auth_methods != 0) { 1742 if ((options.protocol & SSH_PROTO_1)) 1743 fatal("AuthenticationMethods is not supported with " 1744 "SSH protocol 1"); 1745 for (n = 0; n < options.num_auth_methods; n++) { 1746 if (auth2_methods_valid(options.auth_methods[n], 1747 1) == 0) 1748 break; 1749 } 1750 if (n >= options.num_auth_methods) 1751 fatal("AuthenticationMethods cannot be satisfied by " 1752 "enabled authentication methods"); 1753 } 1754 1755 /* set default channel AF */ 1756 channel_set_af(options.address_family); 1757 1758 /* Check that there are no remaining arguments. */ 1759 if (optind < ac) { 1760 fprintf(stderr, "Extra argument %s.\n", av[optind]); 1761 exit(1); 1762 } 1763 1764 debug("sshd version %s, %s", SSH_VERSION, 1765 #ifdef WITH_OPENSSL 1766 SSLeay_version(SSLEAY_VERSION) 1767 #else 1768 "without OpenSSL" 1769 #endif 1770 ); 1771 1772 /* Store privilege separation user for later use if required. */ 1773 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { 1774 if (use_privsep || options.kerberos_authentication) 1775 fatal("Privilege separation user %s does not exist", 1776 SSH_PRIVSEP_USER); 1777 } else { 1778 explicit_bzero(privsep_pw->pw_passwd, 1779 strlen(privsep_pw->pw_passwd)); 1780 privsep_pw = pwcopy(privsep_pw); 1781 free(privsep_pw->pw_passwd); 1782 privsep_pw->pw_passwd = xstrdup("*"); 1783 } 1784 endpwent(); 1785 1786 /* load host keys */ 1787 sensitive_data.host_keys = xcalloc(options.num_host_key_files, 1788 sizeof(Key *)); 1789 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files, 1790 sizeof(Key *)); 1791 1792 if (options.host_key_agent) { 1793 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME)) 1794 setenv(SSH_AUTHSOCKET_ENV_NAME, 1795 options.host_key_agent, 1); 1796 if ((r = ssh_get_authentication_socket(NULL)) == 0) 1797 have_agent = 1; 1798 else 1799 error("Could not connect to agent \"%s\": %s", 1800 options.host_key_agent, ssh_err(r)); 1801 } 1802 1803 for (i = 0; i < options.num_host_key_files; i++) { 1804 if (options.host_key_files[i] == NULL) 1805 continue; 1806 key = key_load_private(options.host_key_files[i], "", NULL); 1807 pubkey = key_load_public(options.host_key_files[i], NULL); 1808 if (pubkey == NULL && key != NULL) 1809 pubkey = key_demote(key); 1810 sensitive_data.host_keys[i] = key; 1811 sensitive_data.host_pubkeys[i] = pubkey; 1812 1813 if (key == NULL && pubkey != NULL && pubkey->type != KEY_RSA1 && 1814 have_agent) { 1815 debug("will rely on agent for hostkey %s", 1816 options.host_key_files[i]); 1817 keytype = pubkey->type; 1818 } else if (key != NULL) { 1819 keytype = key->type; 1820 } else { 1821 error("Could not load host key: %s", 1822 options.host_key_files[i]); 1823 sensitive_data.host_keys[i] = NULL; 1824 sensitive_data.host_pubkeys[i] = NULL; 1825 continue; 1826 } 1827 1828 switch (keytype) { 1829 case KEY_RSA1: 1830 sensitive_data.ssh1_host_key = key; 1831 sensitive_data.have_ssh1_key = 1; 1832 break; 1833 case KEY_RSA: 1834 case KEY_DSA: 1835 case KEY_ECDSA: 1836 case KEY_ED25519: 1837 if (have_agent || key != NULL) 1838 sensitive_data.have_ssh2_key = 1; 1839 break; 1840 } 1841 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash, 1842 SSH_FP_DEFAULT)) == NULL) 1843 fatal("sshkey_fingerprint failed"); 1844 debug("%s host key #%d: %s %s", 1845 key ? "private" : "agent", i, keytype == KEY_RSA1 ? 1846 sshkey_type(pubkey) : sshkey_ssh_name(pubkey), fp); 1847 free(fp); 1848 } 1849 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { 1850 logit("Disabling protocol version 1. Could not load host key"); 1851 options.protocol &= ~SSH_PROTO_1; 1852 } 1853 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { 1854 logit("Disabling protocol version 2. Could not load host key"); 1855 options.protocol &= ~SSH_PROTO_2; 1856 } 1857 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { 1858 logit("sshd: no hostkeys available -- exiting."); 1859 exit(1); 1860 } 1861 1862 /* 1863 * Load certificates. They are stored in an array at identical 1864 * indices to the public keys that they relate to. 1865 */ 1866 sensitive_data.host_certificates = xcalloc(options.num_host_key_files, 1867 sizeof(Key *)); 1868 for (i = 0; i < options.num_host_key_files; i++) 1869 sensitive_data.host_certificates[i] = NULL; 1870 1871 for (i = 0; i < options.num_host_cert_files; i++) { 1872 if (options.host_cert_files[i] == NULL) 1873 continue; 1874 key = key_load_public(options.host_cert_files[i], NULL); 1875 if (key == NULL) { 1876 error("Could not load host certificate: %s", 1877 options.host_cert_files[i]); 1878 continue; 1879 } 1880 if (!key_is_cert(key)) { 1881 error("Certificate file is not a certificate: %s", 1882 options.host_cert_files[i]); 1883 key_free(key); 1884 continue; 1885 } 1886 /* Find matching private key */ 1887 for (j = 0; j < options.num_host_key_files; j++) { 1888 if (key_equal_public(key, 1889 sensitive_data.host_keys[j])) { 1890 sensitive_data.host_certificates[j] = key; 1891 break; 1892 } 1893 } 1894 if (j >= options.num_host_key_files) { 1895 error("No matching private key for certificate: %s", 1896 options.host_cert_files[i]); 1897 key_free(key); 1898 continue; 1899 } 1900 sensitive_data.host_certificates[j] = key; 1901 debug("host certificate: #%d type %d %s", j, key->type, 1902 key_type(key)); 1903 } 1904 1905 #ifdef WITH_SSH1 1906 /* Check certain values for sanity. */ 1907 if (options.protocol & SSH_PROTO_1) { 1908 if (options.server_key_bits < SSH_RSA_MINIMUM_MODULUS_SIZE || 1909 options.server_key_bits > OPENSSL_RSA_MAX_MODULUS_BITS) { 1910 fprintf(stderr, "Bad server key size.\n"); 1911 exit(1); 1912 } 1913 /* 1914 * Check that server and host key lengths differ sufficiently. This 1915 * is necessary to make double encryption work with rsaref. Oh, I 1916 * hate software patents. I dont know if this can go? Niels 1917 */ 1918 if (options.server_key_bits > 1919 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - 1920 SSH_KEY_BITS_RESERVED && options.server_key_bits < 1921 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1922 SSH_KEY_BITS_RESERVED) { 1923 options.server_key_bits = 1924 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1925 SSH_KEY_BITS_RESERVED; 1926 debug("Forcing server key to %d bits to make it differ from host key.", 1927 options.server_key_bits); 1928 } 1929 } 1930 #endif 1931 1932 if (use_privsep) { 1933 struct stat st; 1934 1935 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || 1936 (S_ISDIR(st.st_mode) == 0)) 1937 fatal("Missing privilege separation directory: %s", 1938 _PATH_PRIVSEP_CHROOT_DIR); 1939 1940 #ifdef HAVE_CYGWIN 1941 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && 1942 (st.st_uid != getuid () || 1943 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) 1944 #else 1945 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) 1946 #endif 1947 fatal("%s must be owned by root and not group or " 1948 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); 1949 } 1950 1951 if (test_flag > 1) { 1952 if (server_match_spec_complete(connection_info) == 1) 1953 parse_server_match_config(&options, connection_info); 1954 dump_config(&options); 1955 } 1956 1957 /* Configuration looks good, so exit if in test mode. */ 1958 if (test_flag) 1959 exit(0); 1960 1961 /* 1962 * Clear out any supplemental groups we may have inherited. This 1963 * prevents inadvertent creation of files with bad modes (in the 1964 * portable version at least, it's certainly possible for PAM 1965 * to create a file, and we can't control the code in every 1966 * module which might be used). 1967 */ 1968 if (setgroups(0, NULL) < 0) 1969 debug("setgroups() failed: %.200s", strerror(errno)); 1970 1971 if (rexec_flag) { 1972 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); 1973 for (i = 0; i < rexec_argc; i++) { 1974 debug("rexec_argv[%d]='%s'", i, saved_argv[i]); 1975 rexec_argv[i] = saved_argv[i]; 1976 } 1977 rexec_argv[rexec_argc] = "-R"; 1978 rexec_argv[rexec_argc + 1] = NULL; 1979 } 1980 1981 /* Ensure that umask disallows at least group and world write */ 1982 new_umask = umask(0077) | 0022; 1983 (void) umask(new_umask); 1984 1985 /* Initialize the log (it is reinitialized below in case we forked). */ 1986 if (debug_flag && (!inetd_flag || rexeced_flag)) 1987 log_stderr = 1; 1988 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1989 1990 /* 1991 * If not in debugging mode, and not started from inetd, disconnect 1992 * from the controlling terminal, and fork. The original process 1993 * exits. 1994 */ 1995 if (!(debug_flag || inetd_flag || no_daemon_flag)) { 1996 #ifdef TIOCNOTTY 1997 int fd; 1998 #endif /* TIOCNOTTY */ 1999 if (daemon(0, 0) < 0) 2000 fatal("daemon() failed: %.200s", strerror(errno)); 2001 2002 /* Disconnect from the controlling tty. */ 2003 #ifdef TIOCNOTTY 2004 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); 2005 if (fd >= 0) { 2006 (void) ioctl(fd, TIOCNOTTY, NULL); 2007 close(fd); 2008 } 2009 #endif /* TIOCNOTTY */ 2010 } 2011 /* Reinitialize the log (because of the fork above). */ 2012 log_init(__progname, options.log_level, options.log_facility, log_stderr); 2013 2014 /* Avoid killing the process in high-pressure swapping environments. */ 2015 if (!inetd_flag && madvise(NULL, 0, MADV_PROTECT) != 0) 2016 debug("madvise(): %.200s", strerror(errno)); 2017 2018 /* Chdir to the root directory so that the current disk can be 2019 unmounted if desired. */ 2020 if (chdir("/") == -1) 2021 error("chdir(\"/\"): %s", strerror(errno)); 2022 2023 /* ignore SIGPIPE */ 2024 signal(SIGPIPE, SIG_IGN); 2025 2026 /* Get a connection, either from inetd or a listening TCP socket */ 2027 if (inetd_flag) { 2028 server_accept_inetd(&sock_in, &sock_out); 2029 } else { 2030 platform_pre_listen(); 2031 server_listen(); 2032 2033 if (options.protocol & SSH_PROTO_1) 2034 generate_ephemeral_server_key(); 2035 2036 signal(SIGHUP, sighup_handler); 2037 signal(SIGCHLD, main_sigchld_handler); 2038 signal(SIGTERM, sigterm_handler); 2039 signal(SIGQUIT, sigterm_handler); 2040 2041 /* 2042 * Write out the pid file after the sigterm handler 2043 * is setup and the listen sockets are bound 2044 */ 2045 if (options.pid_file != NULL && !debug_flag) { 2046 FILE *f = fopen(options.pid_file, "w"); 2047 2048 if (f == NULL) { 2049 error("Couldn't create pid file \"%s\": %s", 2050 options.pid_file, strerror(errno)); 2051 } else { 2052 fprintf(f, "%ld\n", (long) getpid()); 2053 fclose(f); 2054 } 2055 } 2056 2057 /* Accept a connection and return in a forked child */ 2058 server_accept_loop(&sock_in, &sock_out, 2059 &newsock, config_s); 2060 } 2061 2062 /* This is the child processing a new connection. */ 2063 setproctitle("%s", "[accepted]"); 2064 2065 /* 2066 * Create a new session and process group since the 4.4BSD 2067 * setlogin() affects the entire process group. We don't 2068 * want the child to be able to affect the parent. 2069 */ 2070 #if !defined(SSHD_ACQUIRES_CTTY) 2071 /* 2072 * If setsid is called, on some platforms sshd will later acquire a 2073 * controlling terminal which will result in "could not set 2074 * controlling tty" errors. 2075 */ 2076 if (!debug_flag && !inetd_flag && setsid() < 0) 2077 error("setsid: %.100s", strerror(errno)); 2078 #endif 2079 2080 if (rexec_flag) { 2081 int fd; 2082 2083 debug("rexec start in %d out %d newsock %d pipe %d sock %d", 2084 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 2085 dup2(newsock, STDIN_FILENO); 2086 dup2(STDIN_FILENO, STDOUT_FILENO); 2087 if (startup_pipe == -1) 2088 close(REEXEC_STARTUP_PIPE_FD); 2089 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) { 2090 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); 2091 close(startup_pipe); 2092 startup_pipe = REEXEC_STARTUP_PIPE_FD; 2093 } 2094 2095 dup2(config_s[1], REEXEC_CONFIG_PASS_FD); 2096 close(config_s[1]); 2097 2098 execv(rexec_argv[0], rexec_argv); 2099 2100 /* Reexec has failed, fall back and continue */ 2101 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); 2102 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); 2103 log_init(__progname, options.log_level, 2104 options.log_facility, log_stderr); 2105 2106 /* Clean up fds */ 2107 close(REEXEC_CONFIG_PASS_FD); 2108 newsock = sock_out = sock_in = dup(STDIN_FILENO); 2109 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 2110 dup2(fd, STDIN_FILENO); 2111 dup2(fd, STDOUT_FILENO); 2112 if (fd > STDERR_FILENO) 2113 close(fd); 2114 } 2115 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", 2116 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 2117 } 2118 2119 /* Executed child processes don't need these. */ 2120 fcntl(sock_out, F_SETFD, FD_CLOEXEC); 2121 fcntl(sock_in, F_SETFD, FD_CLOEXEC); 2122 2123 /* 2124 * Disable the key regeneration alarm. We will not regenerate the 2125 * key since we are no longer in a position to give it to anyone. We 2126 * will not restart on SIGHUP since it no longer makes sense. 2127 */ 2128 alarm(0); 2129 signal(SIGALRM, SIG_DFL); 2130 signal(SIGHUP, SIG_DFL); 2131 signal(SIGTERM, SIG_DFL); 2132 signal(SIGQUIT, SIG_DFL); 2133 signal(SIGCHLD, SIG_DFL); 2134 signal(SIGINT, SIG_DFL); 2135 2136 #ifdef __FreeBSD__ 2137 /* 2138 * Initialize the resolver. This may not happen automatically 2139 * before privsep chroot(). 2140 */ 2141 if ((_res.options & RES_INIT) == 0) { 2142 debug("res_init()"); 2143 res_init(); 2144 } 2145 #ifdef GSSAPI 2146 /* 2147 * Force GSS-API to parse its configuration and load any 2148 * mechanism plugins. 2149 */ 2150 { 2151 gss_OID_set mechs; 2152 OM_uint32 minor_status; 2153 gss_indicate_mechs(&minor_status, &mechs); 2154 gss_release_oid_set(&minor_status, &mechs); 2155 } 2156 #endif 2157 #endif 2158 2159 /* 2160 * Register our connection. This turns encryption off because we do 2161 * not have a key. 2162 */ 2163 packet_set_connection(sock_in, sock_out); 2164 packet_set_server(); 2165 2166 /* Set SO_KEEPALIVE if requested. */ 2167 if (options.tcp_keep_alive && packet_connection_is_on_socket() && 2168 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) 2169 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 2170 2171 if ((remote_port = get_remote_port()) < 0) { 2172 debug("get_remote_port failed"); 2173 cleanup_exit(255); 2174 } 2175 2176 /* 2177 * We use get_canonical_hostname with usedns = 0 instead of 2178 * get_remote_ipaddr here so IP options will be checked. 2179 */ 2180 (void) get_canonical_hostname(0); 2181 /* 2182 * The rest of the code depends on the fact that 2183 * get_remote_ipaddr() caches the remote ip, even if 2184 * the socket goes away. 2185 */ 2186 remote_ip = get_remote_ipaddr(); 2187 2188 #ifdef SSH_AUDIT_EVENTS 2189 audit_connection_from(remote_ip, remote_port); 2190 #endif 2191 #ifdef LIBWRAP 2192 allow_severity = options.log_facility|LOG_INFO; 2193 deny_severity = options.log_facility|LOG_WARNING; 2194 /* Check whether logins are denied from this host. */ 2195 if (packet_connection_is_on_socket()) { 2196 struct request_info req; 2197 2198 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); 2199 fromhost(&req); 2200 2201 if (!hosts_access(&req)) { 2202 debug("Connection refused by tcp wrapper"); 2203 refuse(&req); 2204 /* NOTREACHED */ 2205 fatal("libwrap refuse returns"); 2206 } 2207 } 2208 #endif /* LIBWRAP */ 2209 2210 /* Log the connection. */ 2211 laddr = get_local_ipaddr(sock_in); 2212 verbose("Connection from %s port %d on %s port %d", 2213 remote_ip, remote_port, laddr, get_local_port()); 2214 free(laddr); 2215 2216 /* 2217 * We don't want to listen forever unless the other side 2218 * successfully authenticates itself. So we set up an alarm which is 2219 * cleared after successful authentication. A limit of zero 2220 * indicates no limit. Note that we don't set the alarm in debugging 2221 * mode; it is just annoying to have the server exit just when you 2222 * are about to discover the bug. 2223 */ 2224 signal(SIGALRM, grace_alarm_handler); 2225 if (!debug_flag) 2226 alarm(options.login_grace_time); 2227 2228 sshd_exchange_identification(sock_in, sock_out); 2229 2230 /* In inetd mode, generate ephemeral key only for proto 1 connections */ 2231 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) 2232 generate_ephemeral_server_key(); 2233 2234 packet_set_nonblocking(); 2235 2236 /* allocate authentication context */ 2237 authctxt = xcalloc(1, sizeof(*authctxt)); 2238 2239 authctxt->loginmsg = &loginmsg; 2240 2241 /* XXX global for cleanup, access from other modules */ 2242 the_authctxt = authctxt; 2243 2244 /* prepare buffer to collect messages to display to user after login */ 2245 buffer_init(&loginmsg); 2246 auth_debug_reset(); 2247 2248 if (use_privsep) { 2249 if (privsep_preauth(authctxt) == 1) 2250 goto authenticated; 2251 } else if (compat20 && have_agent) { 2252 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { 2253 error("Unable to get agent socket: %s", ssh_err(r)); 2254 have_agent = 0; 2255 } 2256 } 2257 2258 /* perform the key exchange */ 2259 /* authenticate user and start session */ 2260 if (compat20) { 2261 do_ssh2_kex(); 2262 do_authentication2(authctxt); 2263 } else { 2264 #ifdef WITH_SSH1 2265 do_ssh1_kex(); 2266 do_authentication(authctxt); 2267 #else 2268 fatal("ssh1 not supported"); 2269 #endif 2270 } 2271 /* 2272 * If we use privilege separation, the unprivileged child transfers 2273 * the current keystate and exits 2274 */ 2275 if (use_privsep) { 2276 mm_send_keystate(pmonitor); 2277 exit(0); 2278 } 2279 2280 authenticated: 2281 /* 2282 * Cancel the alarm we set to limit the time taken for 2283 * authentication. 2284 */ 2285 alarm(0); 2286 signal(SIGALRM, SIG_DFL); 2287 authctxt->authenticated = 1; 2288 if (startup_pipe != -1) { 2289 close(startup_pipe); 2290 startup_pipe = -1; 2291 } 2292 2293 #ifdef SSH_AUDIT_EVENTS 2294 audit_event(SSH_AUTH_SUCCESS); 2295 #endif 2296 2297 #ifdef GSSAPI 2298 if (options.gss_authentication) { 2299 temporarily_use_uid(authctxt->pw); 2300 ssh_gssapi_storecreds(); 2301 restore_uid(); 2302 } 2303 #endif 2304 #ifdef USE_PAM 2305 if (options.use_pam) { 2306 do_pam_setcred(1); 2307 do_pam_session(); 2308 } 2309 #endif 2310 2311 /* 2312 * In privilege separation, we fork another child and prepare 2313 * file descriptor passing. 2314 */ 2315 if (use_privsep) { 2316 privsep_postauth(authctxt); 2317 /* the monitor process [priv] will not return */ 2318 if (!compat20) 2319 destroy_sensitive_data(); 2320 } 2321 2322 packet_set_timeout(options.client_alive_interval, 2323 options.client_alive_count_max); 2324 2325 /* Try to send all our hostkeys to the client */ 2326 if (compat20) 2327 notify_hostkeys(active_state); 2328 2329 /* Start session. */ 2330 do_authenticated(authctxt); 2331 2332 /* The connection has been terminated. */ 2333 packet_get_bytes(&ibytes, &obytes); 2334 verbose("Transferred: sent %llu, received %llu bytes", 2335 (unsigned long long)obytes, (unsigned long long)ibytes); 2336 2337 verbose("Closing connection to %.500s port %d", remote_ip, remote_port); 2338 2339 #ifdef USE_PAM 2340 if (options.use_pam) 2341 finish_pam(); 2342 #endif /* USE_PAM */ 2343 2344 #ifdef SSH_AUDIT_EVENTS 2345 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); 2346 #endif 2347 2348 packet_close(); 2349 2350 if (use_privsep) 2351 mm_terminate(); 2352 2353 exit(0); 2354 } 2355 2356 #ifdef WITH_SSH1 2357 /* 2358 * Decrypt session_key_int using our private server key and private host key 2359 * (key with larger modulus first). 2360 */ 2361 int 2362 ssh1_session_key(BIGNUM *session_key_int) 2363 { 2364 int rsafail = 0; 2365 2366 if (BN_cmp(sensitive_data.server_key->rsa->n, 2367 sensitive_data.ssh1_host_key->rsa->n) > 0) { 2368 /* Server key has bigger modulus. */ 2369 if (BN_num_bits(sensitive_data.server_key->rsa->n) < 2370 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 2371 SSH_KEY_BITS_RESERVED) { 2372 fatal("do_connection: %s: " 2373 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", 2374 get_remote_ipaddr(), 2375 BN_num_bits(sensitive_data.server_key->rsa->n), 2376 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 2377 SSH_KEY_BITS_RESERVED); 2378 } 2379 if (rsa_private_decrypt(session_key_int, session_key_int, 2380 sensitive_data.server_key->rsa) != 0) 2381 rsafail++; 2382 if (rsa_private_decrypt(session_key_int, session_key_int, 2383 sensitive_data.ssh1_host_key->rsa) != 0) 2384 rsafail++; 2385 } else { 2386 /* Host key has bigger modulus (or they are equal). */ 2387 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < 2388 BN_num_bits(sensitive_data.server_key->rsa->n) + 2389 SSH_KEY_BITS_RESERVED) { 2390 fatal("do_connection: %s: " 2391 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", 2392 get_remote_ipaddr(), 2393 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 2394 BN_num_bits(sensitive_data.server_key->rsa->n), 2395 SSH_KEY_BITS_RESERVED); 2396 } 2397 if (rsa_private_decrypt(session_key_int, session_key_int, 2398 sensitive_data.ssh1_host_key->rsa) != 0) 2399 rsafail++; 2400 if (rsa_private_decrypt(session_key_int, session_key_int, 2401 sensitive_data.server_key->rsa) != 0) 2402 rsafail++; 2403 } 2404 return (rsafail); 2405 } 2406 2407 /* 2408 * SSH1 key exchange 2409 */ 2410 static void 2411 do_ssh1_kex(void) 2412 { 2413 int i, len; 2414 int rsafail = 0; 2415 BIGNUM *session_key_int, *fake_key_int, *real_key_int; 2416 u_char session_key[SSH_SESSION_KEY_LENGTH]; 2417 u_char fake_key_bytes[4096 / 8]; 2418 size_t fake_key_len; 2419 u_char cookie[8]; 2420 u_int cipher_type, auth_mask, protocol_flags; 2421 2422 /* 2423 * Generate check bytes that the client must send back in the user 2424 * packet in order for it to be accepted; this is used to defy ip 2425 * spoofing attacks. Note that this only works against somebody 2426 * doing IP spoofing from a remote machine; any machine on the local 2427 * network can still see outgoing packets and catch the random 2428 * cookie. This only affects rhosts authentication, and this is one 2429 * of the reasons why it is inherently insecure. 2430 */ 2431 arc4random_buf(cookie, sizeof(cookie)); 2432 2433 /* 2434 * Send our public key. We include in the packet 64 bits of random 2435 * data that must be matched in the reply in order to prevent IP 2436 * spoofing. 2437 */ 2438 packet_start(SSH_SMSG_PUBLIC_KEY); 2439 for (i = 0; i < 8; i++) 2440 packet_put_char(cookie[i]); 2441 2442 /* Store our public server RSA key. */ 2443 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); 2444 packet_put_bignum(sensitive_data.server_key->rsa->e); 2445 packet_put_bignum(sensitive_data.server_key->rsa->n); 2446 2447 /* Store our public host RSA key. */ 2448 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 2449 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); 2450 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); 2451 2452 /* Put protocol flags. */ 2453 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); 2454 2455 /* Declare which ciphers we support. */ 2456 packet_put_int(cipher_mask_ssh1(0)); 2457 2458 /* Declare supported authentication types. */ 2459 auth_mask = 0; 2460 if (options.rhosts_rsa_authentication) 2461 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; 2462 if (options.rsa_authentication) 2463 auth_mask |= 1 << SSH_AUTH_RSA; 2464 if (options.challenge_response_authentication == 1) 2465 auth_mask |= 1 << SSH_AUTH_TIS; 2466 if (options.password_authentication) 2467 auth_mask |= 1 << SSH_AUTH_PASSWORD; 2468 packet_put_int(auth_mask); 2469 2470 /* Send the packet and wait for it to be sent. */ 2471 packet_send(); 2472 packet_write_wait(); 2473 2474 debug("Sent %d bit server key and %d bit host key.", 2475 BN_num_bits(sensitive_data.server_key->rsa->n), 2476 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 2477 2478 /* Read clients reply (cipher type and session key). */ 2479 packet_read_expect(SSH_CMSG_SESSION_KEY); 2480 2481 /* Get cipher type and check whether we accept this. */ 2482 cipher_type = packet_get_char(); 2483 2484 if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) 2485 packet_disconnect("Warning: client selects unsupported cipher."); 2486 2487 /* Get check bytes from the packet. These must match those we 2488 sent earlier with the public key packet. */ 2489 for (i = 0; i < 8; i++) 2490 if (cookie[i] != packet_get_char()) 2491 packet_disconnect("IP Spoofing check bytes do not match."); 2492 2493 debug("Encryption type: %.200s", cipher_name(cipher_type)); 2494 2495 /* Get the encrypted integer. */ 2496 if ((real_key_int = BN_new()) == NULL) 2497 fatal("do_ssh1_kex: BN_new failed"); 2498 packet_get_bignum(real_key_int); 2499 2500 protocol_flags = packet_get_int(); 2501 packet_set_protocol_flags(protocol_flags); 2502 packet_check_eom(); 2503 2504 /* Setup a fake key in case RSA decryption fails */ 2505 if ((fake_key_int = BN_new()) == NULL) 2506 fatal("do_ssh1_kex: BN_new failed"); 2507 fake_key_len = BN_num_bytes(real_key_int); 2508 if (fake_key_len > sizeof(fake_key_bytes)) 2509 fake_key_len = sizeof(fake_key_bytes); 2510 arc4random_buf(fake_key_bytes, fake_key_len); 2511 if (BN_bin2bn(fake_key_bytes, fake_key_len, fake_key_int) == NULL) 2512 fatal("do_ssh1_kex: BN_bin2bn failed"); 2513 2514 /* Decrypt real_key_int using host/server keys */ 2515 rsafail = PRIVSEP(ssh1_session_key(real_key_int)); 2516 /* If decryption failed, use the fake key. Else, the real key. */ 2517 if (rsafail) 2518 session_key_int = fake_key_int; 2519 else 2520 session_key_int = real_key_int; 2521 2522 /* 2523 * Extract session key from the decrypted integer. The key is in the 2524 * least significant 256 bits of the integer; the first byte of the 2525 * key is in the highest bits. 2526 */ 2527 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); 2528 len = BN_num_bytes(session_key_int); 2529 if (len < 0 || (u_int)len > sizeof(session_key)) { 2530 error("do_ssh1_kex: bad session key len from %s: " 2531 "session_key_int %d > sizeof(session_key) %lu", 2532 get_remote_ipaddr(), len, (u_long)sizeof(session_key)); 2533 rsafail++; 2534 } else { 2535 explicit_bzero(session_key, sizeof(session_key)); 2536 BN_bn2bin(session_key_int, 2537 session_key + sizeof(session_key) - len); 2538 2539 derive_ssh1_session_id( 2540 sensitive_data.ssh1_host_key->rsa->n, 2541 sensitive_data.server_key->rsa->n, 2542 cookie, session_id); 2543 /* 2544 * Xor the first 16 bytes of the session key with the 2545 * session id. 2546 */ 2547 for (i = 0; i < 16; i++) 2548 session_key[i] ^= session_id[i]; 2549 } 2550 2551 /* Destroy the private and public keys. No longer. */ 2552 destroy_sensitive_data(); 2553 2554 if (use_privsep) 2555 mm_ssh1_session_id(session_id); 2556 2557 /* Destroy the decrypted integer. It is no longer needed. */ 2558 BN_clear_free(real_key_int); 2559 BN_clear_free(fake_key_int); 2560 2561 /* Set the session key. From this on all communications will be encrypted. */ 2562 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); 2563 2564 /* Destroy our copy of the session key. It is no longer needed. */ 2565 explicit_bzero(session_key, sizeof(session_key)); 2566 2567 debug("Received session key; encryption turned on."); 2568 2569 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ 2570 packet_start(SSH_SMSG_SUCCESS); 2571 packet_send(); 2572 packet_write_wait(); 2573 } 2574 #endif 2575 2576 int 2577 sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen, 2578 const u_char *data, size_t dlen, u_int flag) 2579 { 2580 int r; 2581 u_int xxx_slen, xxx_dlen = dlen; 2582 2583 if (privkey) { 2584 if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen) < 0)) 2585 fatal("%s: key_sign failed", __func__); 2586 if (slen) 2587 *slen = xxx_slen; 2588 } else if (use_privsep) { 2589 if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen) < 0) 2590 fatal("%s: pubkey_sign failed", __func__); 2591 if (slen) 2592 *slen = xxx_slen; 2593 } else { 2594 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen, 2595 data, dlen, datafellows)) != 0) 2596 fatal("%s: ssh_agent_sign failed: %s", 2597 __func__, ssh_err(r)); 2598 } 2599 return 0; 2600 } 2601 2602 /* SSH2 key exchange */ 2603 static void 2604 do_ssh2_kex(void) 2605 { 2606 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER }; 2607 struct kex *kex; 2608 int r; 2609 2610 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 2611 options.kex_algorithms); 2612 myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal( 2613 options.ciphers); 2614 myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal( 2615 options.ciphers); 2616 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 2617 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 2618 2619 if (options.compression == COMP_NONE) { 2620 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2621 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; 2622 } else if (options.compression == COMP_DELAYED) { 2623 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2624 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; 2625 } 2626 2627 if (options.rekey_limit || options.rekey_interval) 2628 packet_set_rekey_limits((u_int32_t)options.rekey_limit, 2629 (time_t)options.rekey_interval); 2630 2631 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal( 2632 list_hostkey_types()); 2633 2634 /* start key exchange */ 2635 if ((r = kex_setup(active_state, myproposal)) != 0) 2636 fatal("kex_setup: %s", ssh_err(r)); 2637 kex = active_state->kex; 2638 #ifdef WITH_OPENSSL 2639 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 2640 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 2641 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 2642 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 2643 # ifdef OPENSSL_HAS_ECC 2644 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 2645 # endif 2646 #endif 2647 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 2648 kex->server = 1; 2649 kex->client_version_string=client_version_string; 2650 kex->server_version_string=server_version_string; 2651 kex->load_host_public_key=&get_hostkey_public_by_type; 2652 kex->load_host_private_key=&get_hostkey_private_by_type; 2653 kex->host_key_index=&get_hostkey_index; 2654 kex->sign = sshd_hostkey_sign; 2655 2656 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state); 2657 2658 session_id2 = kex->session_id; 2659 session_id2_len = kex->session_id_len; 2660 2661 #ifdef DEBUG_KEXDH 2662 /* send 1st encrypted/maced/compressed message */ 2663 packet_start(SSH2_MSG_IGNORE); 2664 packet_put_cstring("markus"); 2665 packet_send(); 2666 packet_write_wait(); 2667 #endif 2668 debug("KEX done"); 2669 } 2670 2671 /* server specific fatal cleanup */ 2672 void 2673 cleanup_exit(int i) 2674 { 2675 if (the_authctxt) { 2676 do_cleanup(the_authctxt); 2677 if (use_privsep && privsep_is_preauth && 2678 pmonitor != NULL && pmonitor->m_pid > 1) { 2679 debug("Killing privsep child %d", pmonitor->m_pid); 2680 if (kill(pmonitor->m_pid, SIGKILL) != 0 && 2681 errno != ESRCH) 2682 error("%s: kill(%d): %s", __func__, 2683 pmonitor->m_pid, strerror(errno)); 2684 } 2685 } 2686 #ifdef SSH_AUDIT_EVENTS 2687 /* done after do_cleanup so it can cancel the PAM auth 'thread' */ 2688 if (!use_privsep || mm_is_monitor()) 2689 audit_event(SSH_CONNECTION_ABANDON); 2690 #endif 2691 _exit(i); 2692 } 2693