1 /* $OpenBSD: sshd.c,v 1.470 2016/05/24 04:43:45 dtucker Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This program is the ssh daemon. It listens for connections from clients, 7 * and performs authentication, executes use commands or shell, and forwards 8 * information to/from the application to the user client over an encrypted 9 * connection. This can also handle forwarding of X11, TCP/IP, and 10 * authentication agent connections. 11 * 12 * As far as I am concerned, the code I have written for this software 13 * can be used freely for any purpose. Any derived versions of this 14 * software must be clearly marked as such, and if the derived work is 15 * incompatible with the protocol description in the RFC file, it must be 16 * called by a name other than "ssh" or "Secure Shell". 17 * 18 * SSH2 implementation: 19 * Privilege Separation: 20 * 21 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. 22 * Copyright (c) 2002 Niels Provos. All rights reserved. 23 * 24 * Redistribution and use in source and binary forms, with or without 25 * modification, are permitted provided that the following conditions 26 * are met: 27 * 1. Redistributions of source code must retain the above copyright 28 * notice, this list of conditions and the following disclaimer. 29 * 2. Redistributions in binary form must reproduce the above copyright 30 * notice, this list of conditions and the following disclaimer in the 31 * documentation and/or other materials provided with the distribution. 32 * 33 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 34 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 36 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 37 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 39 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 40 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 42 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 43 */ 44 45 #include "includes.h" 46 47 #include <sys/types.h> 48 #include <sys/ioctl.h> 49 #include <sys/socket.h> 50 #ifdef HAVE_SYS_STAT_H 51 # include <sys/stat.h> 52 #endif 53 #ifdef HAVE_SYS_TIME_H 54 # include <sys/time.h> 55 #endif 56 #include "openbsd-compat/sys-tree.h" 57 #include "openbsd-compat/sys-queue.h" 58 #include <sys/wait.h> 59 60 #include <errno.h> 61 #include <fcntl.h> 62 #include <netdb.h> 63 #ifdef HAVE_PATHS_H 64 #include <paths.h> 65 #endif 66 #include <grp.h> 67 #include <pwd.h> 68 #include <signal.h> 69 #include <stdarg.h> 70 #include <stdio.h> 71 #include <stdlib.h> 72 #include <string.h> 73 #include <unistd.h> 74 #include <limits.h> 75 76 #ifdef WITH_OPENSSL 77 #include <openssl/dh.h> 78 #include <openssl/bn.h> 79 #include <openssl/rand.h> 80 #include "openbsd-compat/openssl-compat.h" 81 #endif 82 83 #ifdef HAVE_SECUREWARE 84 #include <sys/security.h> 85 #include <prot.h> 86 #endif 87 88 #include "xmalloc.h" 89 #include "ssh.h" 90 #include "ssh1.h" 91 #include "ssh2.h" 92 #include "rsa.h" 93 #include "sshpty.h" 94 #include "packet.h" 95 #include "log.h" 96 #include "buffer.h" 97 #include "misc.h" 98 #include "match.h" 99 #include "servconf.h" 100 #include "uidswap.h" 101 #include "compat.h" 102 #include "cipher.h" 103 #include "digest.h" 104 #include "key.h" 105 #include "kex.h" 106 #include "myproposal.h" 107 #include "authfile.h" 108 #include "pathnames.h" 109 #include "atomicio.h" 110 #include "canohost.h" 111 #include "hostfile.h" 112 #include "auth.h" 113 #include "authfd.h" 114 #include "msg.h" 115 #include "dispatch.h" 116 #include "channels.h" 117 #include "session.h" 118 #include "monitor_mm.h" 119 #include "monitor.h" 120 #ifdef GSSAPI 121 #include "ssh-gss.h" 122 #endif 123 #include "monitor_wrap.h" 124 #include "ssh-sandbox.h" 125 #include "version.h" 126 #include "ssherr.h" 127 128 #ifndef O_NOCTTY 129 #define O_NOCTTY 0 130 #endif 131 132 /* Re-exec fds */ 133 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) 134 #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) 135 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) 136 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) 137 138 extern char *__progname; 139 140 /* Server configuration options. */ 141 ServerOptions options; 142 143 /* Name of the server configuration file. */ 144 char *config_file_name = _PATH_SERVER_CONFIG_FILE; 145 146 /* 147 * Debug mode flag. This can be set on the command line. If debug 148 * mode is enabled, extra debugging output will be sent to the system 149 * log, the daemon will not go to background, and will exit after processing 150 * the first connection. 151 */ 152 int debug_flag = 0; 153 154 /* Flag indicating that the daemon should only test the configuration and keys. */ 155 int test_flag = 0; 156 157 /* Flag indicating that the daemon is being started from inetd. */ 158 int inetd_flag = 0; 159 160 /* Flag indicating that sshd should not detach and become a daemon. */ 161 int no_daemon_flag = 0; 162 163 /* debug goes to stderr unless inetd_flag is set */ 164 int log_stderr = 0; 165 166 /* Saved arguments to main(). */ 167 char **saved_argv; 168 int saved_argc; 169 170 /* re-exec */ 171 int rexeced_flag = 0; 172 int rexec_flag = 1; 173 int rexec_argc = 0; 174 char **rexec_argv; 175 176 /* 177 * The sockets that the server is listening; this is used in the SIGHUP 178 * signal handler. 179 */ 180 #define MAX_LISTEN_SOCKS 16 181 int listen_socks[MAX_LISTEN_SOCKS]; 182 int num_listen_socks = 0; 183 184 /* 185 * the client's version string, passed by sshd2 in compat mode. if != NULL, 186 * sshd will skip the version-number exchange 187 */ 188 char *client_version_string = NULL; 189 char *server_version_string = NULL; 190 191 /* Daemon's agent connection */ 192 int auth_sock = -1; 193 int have_agent = 0; 194 195 /* 196 * Any really sensitive data in the application is contained in this 197 * structure. The idea is that this structure could be locked into memory so 198 * that the pages do not get written into swap. However, there are some 199 * problems. The private key contains BIGNUMs, and we do not (in principle) 200 * have access to the internals of them, and locking just the structure is 201 * not very useful. Currently, memory locking is not implemented. 202 */ 203 struct { 204 Key *server_key; /* ephemeral server key */ 205 Key *ssh1_host_key; /* ssh1 host key */ 206 Key **host_keys; /* all private host keys */ 207 Key **host_pubkeys; /* all public host keys */ 208 Key **host_certificates; /* all public host certificates */ 209 int have_ssh1_key; 210 int have_ssh2_key; 211 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; 212 } sensitive_data; 213 214 /* 215 * Flag indicating whether the RSA server key needs to be regenerated. 216 * Is set in the SIGALRM handler and cleared when the key is regenerated. 217 */ 218 static volatile sig_atomic_t key_do_regen = 0; 219 220 /* This is set to true when a signal is received. */ 221 static volatile sig_atomic_t received_sighup = 0; 222 static volatile sig_atomic_t received_sigterm = 0; 223 224 /* session identifier, used by RSA-auth */ 225 u_char session_id[16]; 226 227 /* same for ssh2 */ 228 u_char *session_id2 = NULL; 229 u_int session_id2_len = 0; 230 231 /* record remote hostname or ip */ 232 u_int utmp_len = HOST_NAME_MAX+1; 233 234 /* options.max_startup sized array of fd ints */ 235 int *startup_pipes = NULL; 236 int startup_pipe; /* in child */ 237 238 /* variables used for privilege separation */ 239 int use_privsep = -1; 240 struct monitor *pmonitor = NULL; 241 int privsep_is_preauth = 1; 242 243 /* global authentication context */ 244 Authctxt *the_authctxt = NULL; 245 246 /* sshd_config buffer */ 247 Buffer cfg; 248 249 /* message to be displayed after login */ 250 Buffer loginmsg; 251 252 /* Unprivileged user */ 253 struct passwd *privsep_pw = NULL; 254 255 /* Prototypes for various functions defined later in this file. */ 256 void destroy_sensitive_data(void); 257 void demote_sensitive_data(void); 258 259 #ifdef WITH_SSH1 260 static void do_ssh1_kex(void); 261 #endif 262 static void do_ssh2_kex(void); 263 264 /* 265 * Close all listening sockets 266 */ 267 static void 268 close_listen_socks(void) 269 { 270 int i; 271 272 for (i = 0; i < num_listen_socks; i++) 273 close(listen_socks[i]); 274 num_listen_socks = -1; 275 } 276 277 static void 278 close_startup_pipes(void) 279 { 280 int i; 281 282 if (startup_pipes) 283 for (i = 0; i < options.max_startups; i++) 284 if (startup_pipes[i] != -1) 285 close(startup_pipes[i]); 286 } 287 288 /* 289 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; 290 * the effect is to reread the configuration file (and to regenerate 291 * the server key). 292 */ 293 294 /*ARGSUSED*/ 295 static void 296 sighup_handler(int sig) 297 { 298 int save_errno = errno; 299 300 received_sighup = 1; 301 signal(SIGHUP, sighup_handler); 302 errno = save_errno; 303 } 304 305 /* 306 * Called from the main program after receiving SIGHUP. 307 * Restarts the server. 308 */ 309 static void 310 sighup_restart(void) 311 { 312 logit("Received SIGHUP; restarting."); 313 platform_pre_restart(); 314 close_listen_socks(); 315 close_startup_pipes(); 316 alarm(0); /* alarm timer persists across exec */ 317 signal(SIGHUP, SIG_IGN); /* will be restored after exec */ 318 execv(saved_argv[0], saved_argv); 319 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], 320 strerror(errno)); 321 exit(1); 322 } 323 324 /* 325 * Generic signal handler for terminating signals in the master daemon. 326 */ 327 /*ARGSUSED*/ 328 static void 329 sigterm_handler(int sig) 330 { 331 received_sigterm = sig; 332 } 333 334 /* 335 * SIGCHLD handler. This is called whenever a child dies. This will then 336 * reap any zombies left by exited children. 337 */ 338 /*ARGSUSED*/ 339 static void 340 main_sigchld_handler(int sig) 341 { 342 int save_errno = errno; 343 pid_t pid; 344 int status; 345 346 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 347 (pid < 0 && errno == EINTR)) 348 ; 349 350 signal(SIGCHLD, main_sigchld_handler); 351 errno = save_errno; 352 } 353 354 /* 355 * Signal handler for the alarm after the login grace period has expired. 356 */ 357 /*ARGSUSED*/ 358 static void 359 grace_alarm_handler(int sig) 360 { 361 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) 362 kill(pmonitor->m_pid, SIGALRM); 363 364 /* 365 * Try to kill any processes that we have spawned, E.g. authorized 366 * keys command helpers. 367 */ 368 if (getpgid(0) == getpid()) { 369 signal(SIGTERM, SIG_IGN); 370 kill(0, SIGTERM); 371 } 372 373 /* Log error and exit. */ 374 sigdie("Timeout before authentication for %s port %d", 375 ssh_remote_ipaddr(active_state), ssh_remote_port(active_state)); 376 } 377 378 /* 379 * Signal handler for the key regeneration alarm. Note that this 380 * alarm only occurs in the daemon waiting for connections, and it does not 381 * do anything with the private key or random state before forking. 382 * Thus there should be no concurrency control/asynchronous execution 383 * problems. 384 */ 385 static void 386 generate_ephemeral_server_key(void) 387 { 388 verbose("Generating %s%d bit RSA key.", 389 sensitive_data.server_key ? "new " : "", options.server_key_bits); 390 if (sensitive_data.server_key != NULL) 391 key_free(sensitive_data.server_key); 392 sensitive_data.server_key = key_generate(KEY_RSA1, 393 options.server_key_bits); 394 verbose("RSA key generation complete."); 395 396 arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); 397 } 398 399 /*ARGSUSED*/ 400 static void 401 key_regeneration_alarm(int sig) 402 { 403 int save_errno = errno; 404 405 signal(SIGALRM, SIG_DFL); 406 errno = save_errno; 407 key_do_regen = 1; 408 } 409 410 static void 411 sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out) 412 { 413 u_int i; 414 int mismatch; 415 int remote_major, remote_minor; 416 int major, minor; 417 char *s, *newline = "\n"; 418 char buf[256]; /* Must not be larger than remote_version. */ 419 char remote_version[256]; /* Must be at least as big as buf. */ 420 421 if ((options.protocol & SSH_PROTO_1) && 422 (options.protocol & SSH_PROTO_2)) { 423 major = PROTOCOL_MAJOR_1; 424 minor = 99; 425 } else if (options.protocol & SSH_PROTO_2) { 426 major = PROTOCOL_MAJOR_2; 427 minor = PROTOCOL_MINOR_2; 428 newline = "\r\n"; 429 } else { 430 major = PROTOCOL_MAJOR_1; 431 minor = PROTOCOL_MINOR_1; 432 } 433 434 xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s", 435 major, minor, SSH_VERSION, 436 *options.version_addendum == '\0' ? "" : " ", 437 options.version_addendum, newline); 438 439 /* Send our protocol version identification. */ 440 if (atomicio(vwrite, sock_out, server_version_string, 441 strlen(server_version_string)) 442 != strlen(server_version_string)) { 443 logit("Could not write ident string to %s port %d", 444 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 445 cleanup_exit(255); 446 } 447 448 /* Read other sides version identification. */ 449 memset(buf, 0, sizeof(buf)); 450 for (i = 0; i < sizeof(buf) - 1; i++) { 451 if (atomicio(read, sock_in, &buf[i], 1) != 1) { 452 logit("Did not receive identification string " 453 "from %s port %d", 454 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 455 cleanup_exit(255); 456 } 457 if (buf[i] == '\r') { 458 buf[i] = 0; 459 /* Kludge for F-Secure Macintosh < 1.0.2 */ 460 if (i == 12 && 461 strncmp(buf, "SSH-1.5-W1.0", 12) == 0) 462 break; 463 continue; 464 } 465 if (buf[i] == '\n') { 466 buf[i] = 0; 467 break; 468 } 469 } 470 buf[sizeof(buf) - 1] = 0; 471 client_version_string = xstrdup(buf); 472 473 /* 474 * Check that the versions match. In future this might accept 475 * several versions and set appropriate flags to handle them. 476 */ 477 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", 478 &remote_major, &remote_minor, remote_version) != 3) { 479 s = "Protocol mismatch.\n"; 480 (void) atomicio(vwrite, sock_out, s, strlen(s)); 481 logit("Bad protocol version identification '%.100s' " 482 "from %s port %d", client_version_string, 483 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 484 close(sock_in); 485 close(sock_out); 486 cleanup_exit(255); 487 } 488 debug("Client protocol version %d.%d; client software version %.100s", 489 remote_major, remote_minor, remote_version); 490 491 ssh->compat = compat_datafellows(remote_version); 492 493 if ((ssh->compat & SSH_BUG_PROBE) != 0) { 494 logit("probed from %s port %d with %s. Don't panic.", 495 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 496 client_version_string); 497 cleanup_exit(255); 498 } 499 if ((ssh->compat & SSH_BUG_SCANNER) != 0) { 500 logit("scanned from %s port %d with %s. Don't panic.", 501 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 502 client_version_string); 503 cleanup_exit(255); 504 } 505 if ((ssh->compat & SSH_BUG_RSASIGMD5) != 0) { 506 logit("Client version \"%.100s\" uses unsafe RSA signature " 507 "scheme; disabling use of RSA keys", remote_version); 508 } 509 if ((ssh->compat & SSH_BUG_DERIVEKEY) != 0) { 510 fatal("Client version \"%.100s\" uses unsafe key agreement; " 511 "refusing connection", remote_version); 512 } 513 514 mismatch = 0; 515 switch (remote_major) { 516 case 1: 517 if (remote_minor == 99) { 518 if (options.protocol & SSH_PROTO_2) 519 enable_compat20(); 520 else 521 mismatch = 1; 522 break; 523 } 524 if (!(options.protocol & SSH_PROTO_1)) { 525 mismatch = 1; 526 break; 527 } 528 if (remote_minor < 3) { 529 packet_disconnect("Your ssh version is too old and " 530 "is no longer supported. Please install a newer version."); 531 } else if (remote_minor == 3) { 532 /* note that this disables agent-forwarding */ 533 enable_compat13(); 534 } 535 break; 536 case 2: 537 if (options.protocol & SSH_PROTO_2) { 538 enable_compat20(); 539 break; 540 } 541 /* FALLTHROUGH */ 542 default: 543 mismatch = 1; 544 break; 545 } 546 chop(server_version_string); 547 debug("Local version string %.200s", server_version_string); 548 549 if (mismatch) { 550 s = "Protocol major versions differ.\n"; 551 (void) atomicio(vwrite, sock_out, s, strlen(s)); 552 close(sock_in); 553 close(sock_out); 554 logit("Protocol major versions differ for %s port %d: " 555 "%.200s vs. %.200s", 556 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 557 server_version_string, client_version_string); 558 cleanup_exit(255); 559 } 560 } 561 562 /* Destroy the host and server keys. They will no longer be needed. */ 563 void 564 destroy_sensitive_data(void) 565 { 566 int i; 567 568 if (sensitive_data.server_key) { 569 key_free(sensitive_data.server_key); 570 sensitive_data.server_key = NULL; 571 } 572 for (i = 0; i < options.num_host_key_files; i++) { 573 if (sensitive_data.host_keys[i]) { 574 key_free(sensitive_data.host_keys[i]); 575 sensitive_data.host_keys[i] = NULL; 576 } 577 if (sensitive_data.host_certificates[i]) { 578 key_free(sensitive_data.host_certificates[i]); 579 sensitive_data.host_certificates[i] = NULL; 580 } 581 } 582 sensitive_data.ssh1_host_key = NULL; 583 explicit_bzero(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); 584 } 585 586 /* Demote private to public keys for network child */ 587 void 588 demote_sensitive_data(void) 589 { 590 Key *tmp; 591 int i; 592 593 if (sensitive_data.server_key) { 594 tmp = key_demote(sensitive_data.server_key); 595 key_free(sensitive_data.server_key); 596 sensitive_data.server_key = tmp; 597 } 598 599 for (i = 0; i < options.num_host_key_files; i++) { 600 if (sensitive_data.host_keys[i]) { 601 tmp = key_demote(sensitive_data.host_keys[i]); 602 key_free(sensitive_data.host_keys[i]); 603 sensitive_data.host_keys[i] = tmp; 604 if (tmp->type == KEY_RSA1) 605 sensitive_data.ssh1_host_key = tmp; 606 } 607 /* Certs do not need demotion */ 608 } 609 610 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ 611 } 612 613 static void 614 privsep_preauth_child(void) 615 { 616 u_int32_t rnd[256]; 617 gid_t gidset[1]; 618 619 /* Enable challenge-response authentication for privilege separation */ 620 privsep_challenge_enable(); 621 622 #ifdef GSSAPI 623 /* Cache supported mechanism OIDs for later use */ 624 if (options.gss_authentication) 625 ssh_gssapi_prepare_supported_oids(); 626 #endif 627 628 arc4random_stir(); 629 arc4random_buf(rnd, sizeof(rnd)); 630 #ifdef WITH_OPENSSL 631 RAND_seed(rnd, sizeof(rnd)); 632 if ((RAND_bytes((u_char *)rnd, 1)) != 1) 633 fatal("%s: RAND_bytes failed", __func__); 634 #endif 635 explicit_bzero(rnd, sizeof(rnd)); 636 637 /* Demote the private keys to public keys. */ 638 demote_sensitive_data(); 639 640 /* Demote the child */ 641 if (getuid() == 0 || geteuid() == 0) { 642 /* Change our root directory */ 643 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) 644 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, 645 strerror(errno)); 646 if (chdir("/") == -1) 647 fatal("chdir(\"/\"): %s", strerror(errno)); 648 649 /* Drop our privileges */ 650 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, 651 (u_int)privsep_pw->pw_gid); 652 gidset[0] = privsep_pw->pw_gid; 653 if (setgroups(1, gidset) < 0) 654 fatal("setgroups: %.100s", strerror(errno)); 655 permanently_set_uid(privsep_pw); 656 } 657 } 658 659 static int 660 privsep_preauth(Authctxt *authctxt) 661 { 662 int status, r; 663 pid_t pid; 664 struct ssh_sandbox *box = NULL; 665 666 /* Set up unprivileged child process to deal with network data */ 667 pmonitor = monitor_init(); 668 /* Store a pointer to the kex for later rekeying */ 669 pmonitor->m_pkex = &active_state->kex; 670 671 if (use_privsep == PRIVSEP_ON) 672 box = ssh_sandbox_init(pmonitor); 673 pid = fork(); 674 if (pid == -1) { 675 fatal("fork of unprivileged child failed"); 676 } else if (pid != 0) { 677 debug2("Network child is on pid %ld", (long)pid); 678 679 pmonitor->m_pid = pid; 680 if (have_agent) { 681 r = ssh_get_authentication_socket(&auth_sock); 682 if (r != 0) { 683 error("Could not get agent socket: %s", 684 ssh_err(r)); 685 have_agent = 0; 686 } 687 } 688 if (box != NULL) 689 ssh_sandbox_parent_preauth(box, pid); 690 monitor_child_preauth(authctxt, pmonitor); 691 692 /* Sync memory */ 693 monitor_sync(pmonitor); 694 695 /* Wait for the child's exit status */ 696 while (waitpid(pid, &status, 0) < 0) { 697 if (errno == EINTR) 698 continue; 699 pmonitor->m_pid = -1; 700 fatal("%s: waitpid: %s", __func__, strerror(errno)); 701 } 702 privsep_is_preauth = 0; 703 pmonitor->m_pid = -1; 704 if (WIFEXITED(status)) { 705 if (WEXITSTATUS(status) != 0) 706 fatal("%s: preauth child exited with status %d", 707 __func__, WEXITSTATUS(status)); 708 } else if (WIFSIGNALED(status)) 709 fatal("%s: preauth child terminated by signal %d", 710 __func__, WTERMSIG(status)); 711 if (box != NULL) 712 ssh_sandbox_parent_finish(box); 713 return 1; 714 } else { 715 /* child */ 716 close(pmonitor->m_sendfd); 717 close(pmonitor->m_log_recvfd); 718 719 /* Arrange for logging to be sent to the monitor */ 720 set_log_handler(mm_log_handler, pmonitor); 721 722 privsep_preauth_child(); 723 setproctitle("%s", "[net]"); 724 if (box != NULL) 725 ssh_sandbox_child(box); 726 727 return 0; 728 } 729 } 730 731 static void 732 privsep_postauth(Authctxt *authctxt) 733 { 734 u_int32_t rnd[256]; 735 736 #ifdef DISABLE_FD_PASSING 737 if (1) { 738 #else 739 if (authctxt->pw->pw_uid == 0 || options.use_login) { 740 #endif 741 /* File descriptor passing is broken or root login */ 742 use_privsep = 0; 743 goto skip; 744 } 745 746 /* New socket pair */ 747 monitor_reinit(pmonitor); 748 749 pmonitor->m_pid = fork(); 750 if (pmonitor->m_pid == -1) 751 fatal("fork of unprivileged child failed"); 752 else if (pmonitor->m_pid != 0) { 753 verbose("User child is on pid %ld", (long)pmonitor->m_pid); 754 buffer_clear(&loginmsg); 755 monitor_child_postauth(pmonitor); 756 757 /* NEVERREACHED */ 758 exit(0); 759 } 760 761 /* child */ 762 763 close(pmonitor->m_sendfd); 764 pmonitor->m_sendfd = -1; 765 766 /* Demote the private keys to public keys. */ 767 demote_sensitive_data(); 768 769 arc4random_stir(); 770 arc4random_buf(rnd, sizeof(rnd)); 771 #ifdef WITH_OPENSSL 772 RAND_seed(rnd, sizeof(rnd)); 773 if ((RAND_bytes((u_char *)rnd, 1)) != 1) 774 fatal("%s: RAND_bytes failed", __func__); 775 #endif 776 explicit_bzero(rnd, sizeof(rnd)); 777 778 /* Drop privileges */ 779 do_setusercontext(authctxt->pw); 780 781 skip: 782 /* It is safe now to apply the key state */ 783 monitor_apply_keystate(pmonitor); 784 785 /* 786 * Tell the packet layer that authentication was successful, since 787 * this information is not part of the key state. 788 */ 789 packet_set_authenticated(); 790 } 791 792 static char * 793 list_hostkey_types(void) 794 { 795 Buffer b; 796 const char *p; 797 char *ret; 798 int i; 799 Key *key; 800 801 buffer_init(&b); 802 for (i = 0; i < options.num_host_key_files; i++) { 803 key = sensitive_data.host_keys[i]; 804 if (key == NULL) 805 key = sensitive_data.host_pubkeys[i]; 806 if (key == NULL || key->type == KEY_RSA1) 807 continue; 808 /* Check that the key is accepted in HostkeyAlgorithms */ 809 if (match_pattern_list(sshkey_ssh_name(key), 810 options.hostkeyalgorithms, 0) != 1) { 811 debug3("%s: %s key not permitted by HostkeyAlgorithms", 812 __func__, sshkey_ssh_name(key)); 813 continue; 814 } 815 switch (key->type) { 816 case KEY_RSA: 817 case KEY_DSA: 818 case KEY_ECDSA: 819 case KEY_ED25519: 820 if (buffer_len(&b) > 0) 821 buffer_append(&b, ",", 1); 822 p = key_ssh_name(key); 823 buffer_append(&b, p, strlen(p)); 824 825 /* for RSA we also support SHA2 signatures */ 826 if (key->type == KEY_RSA) { 827 p = ",rsa-sha2-512,rsa-sha2-256"; 828 buffer_append(&b, p, strlen(p)); 829 } 830 break; 831 } 832 /* If the private key has a cert peer, then list that too */ 833 key = sensitive_data.host_certificates[i]; 834 if (key == NULL) 835 continue; 836 switch (key->type) { 837 case KEY_RSA_CERT: 838 case KEY_DSA_CERT: 839 case KEY_ECDSA_CERT: 840 case KEY_ED25519_CERT: 841 if (buffer_len(&b) > 0) 842 buffer_append(&b, ",", 1); 843 p = key_ssh_name(key); 844 buffer_append(&b, p, strlen(p)); 845 break; 846 } 847 } 848 if ((ret = sshbuf_dup_string(&b)) == NULL) 849 fatal("%s: sshbuf_dup_string failed", __func__); 850 buffer_free(&b); 851 debug("list_hostkey_types: %s", ret); 852 return ret; 853 } 854 855 static Key * 856 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh) 857 { 858 int i; 859 Key *key; 860 861 for (i = 0; i < options.num_host_key_files; i++) { 862 switch (type) { 863 case KEY_RSA_CERT: 864 case KEY_DSA_CERT: 865 case KEY_ECDSA_CERT: 866 case KEY_ED25519_CERT: 867 key = sensitive_data.host_certificates[i]; 868 break; 869 default: 870 key = sensitive_data.host_keys[i]; 871 if (key == NULL && !need_private) 872 key = sensitive_data.host_pubkeys[i]; 873 break; 874 } 875 if (key != NULL && key->type == type && 876 (key->type != KEY_ECDSA || key->ecdsa_nid == nid)) 877 return need_private ? 878 sensitive_data.host_keys[i] : key; 879 } 880 return NULL; 881 } 882 883 Key * 884 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh) 885 { 886 return get_hostkey_by_type(type, nid, 0, ssh); 887 } 888 889 Key * 890 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh) 891 { 892 return get_hostkey_by_type(type, nid, 1, ssh); 893 } 894 895 Key * 896 get_hostkey_by_index(int ind) 897 { 898 if (ind < 0 || ind >= options.num_host_key_files) 899 return (NULL); 900 return (sensitive_data.host_keys[ind]); 901 } 902 903 Key * 904 get_hostkey_public_by_index(int ind, struct ssh *ssh) 905 { 906 if (ind < 0 || ind >= options.num_host_key_files) 907 return (NULL); 908 return (sensitive_data.host_pubkeys[ind]); 909 } 910 911 int 912 get_hostkey_index(Key *key, int compare, struct ssh *ssh) 913 { 914 int i; 915 916 for (i = 0; i < options.num_host_key_files; i++) { 917 if (key_is_cert(key)) { 918 if (key == sensitive_data.host_certificates[i] || 919 (compare && sensitive_data.host_certificates[i] && 920 sshkey_equal(key, 921 sensitive_data.host_certificates[i]))) 922 return (i); 923 } else { 924 if (key == sensitive_data.host_keys[i] || 925 (compare && sensitive_data.host_keys[i] && 926 sshkey_equal(key, sensitive_data.host_keys[i]))) 927 return (i); 928 if (key == sensitive_data.host_pubkeys[i] || 929 (compare && sensitive_data.host_pubkeys[i] && 930 sshkey_equal(key, sensitive_data.host_pubkeys[i]))) 931 return (i); 932 } 933 } 934 return (-1); 935 } 936 937 /* Inform the client of all hostkeys */ 938 static void 939 notify_hostkeys(struct ssh *ssh) 940 { 941 struct sshbuf *buf; 942 struct sshkey *key; 943 int i, nkeys, r; 944 char *fp; 945 946 /* Some clients cannot cope with the hostkeys message, skip those. */ 947 if (datafellows & SSH_BUG_HOSTKEYS) 948 return; 949 950 if ((buf = sshbuf_new()) == NULL) 951 fatal("%s: sshbuf_new", __func__); 952 for (i = nkeys = 0; i < options.num_host_key_files; i++) { 953 key = get_hostkey_public_by_index(i, ssh); 954 if (key == NULL || key->type == KEY_UNSPEC || 955 key->type == KEY_RSA1 || sshkey_is_cert(key)) 956 continue; 957 fp = sshkey_fingerprint(key, options.fingerprint_hash, 958 SSH_FP_DEFAULT); 959 debug3("%s: key %d: %s %s", __func__, i, 960 sshkey_ssh_name(key), fp); 961 free(fp); 962 if (nkeys == 0) { 963 packet_start(SSH2_MSG_GLOBAL_REQUEST); 964 packet_put_cstring("hostkeys-00@openssh.com"); 965 packet_put_char(0); /* want-reply */ 966 } 967 sshbuf_reset(buf); 968 if ((r = sshkey_putb(key, buf)) != 0) 969 fatal("%s: couldn't put hostkey %d: %s", 970 __func__, i, ssh_err(r)); 971 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf)); 972 nkeys++; 973 } 974 debug3("%s: sent %d hostkeys", __func__, nkeys); 975 if (nkeys == 0) 976 fatal("%s: no hostkeys", __func__); 977 packet_send(); 978 sshbuf_free(buf); 979 } 980 981 /* 982 * returns 1 if connection should be dropped, 0 otherwise. 983 * dropping starts at connection #max_startups_begin with a probability 984 * of (max_startups_rate/100). the probability increases linearly until 985 * all connections are dropped for startups > max_startups 986 */ 987 static int 988 drop_connection(int startups) 989 { 990 int p, r; 991 992 if (startups < options.max_startups_begin) 993 return 0; 994 if (startups >= options.max_startups) 995 return 1; 996 if (options.max_startups_rate == 100) 997 return 1; 998 999 p = 100 - options.max_startups_rate; 1000 p *= startups - options.max_startups_begin; 1001 p /= options.max_startups - options.max_startups_begin; 1002 p += options.max_startups_rate; 1003 r = arc4random_uniform(100); 1004 1005 debug("drop_connection: p %d, r %d", p, r); 1006 return (r < p) ? 1 : 0; 1007 } 1008 1009 static void 1010 usage(void) 1011 { 1012 fprintf(stderr, "%s, %s\n", 1013 SSH_RELEASE, 1014 #ifdef WITH_OPENSSL 1015 SSLeay_version(SSLEAY_VERSION) 1016 #else 1017 "without OpenSSL" 1018 #endif 1019 ); 1020 fprintf(stderr, 1021 "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n" 1022 " [-E log_file] [-f config_file] [-g login_grace_time]\n" 1023 " [-h host_key_file] [-k key_gen_time] [-o option] [-p port]\n" 1024 " [-u len]\n" 1025 ); 1026 exit(1); 1027 } 1028 1029 static void 1030 send_rexec_state(int fd, struct sshbuf *conf) 1031 { 1032 struct sshbuf *m; 1033 int r; 1034 1035 debug3("%s: entering fd = %d config len %zu", __func__, fd, 1036 sshbuf_len(conf)); 1037 1038 /* 1039 * Protocol from reexec master to child: 1040 * string configuration 1041 * u_int ephemeral_key_follows 1042 * bignum e (only if ephemeral_key_follows == 1) 1043 * bignum n " 1044 * bignum d " 1045 * bignum iqmp " 1046 * bignum p " 1047 * bignum q " 1048 * string rngseed (only if OpenSSL is not self-seeded) 1049 */ 1050 if ((m = sshbuf_new()) == NULL) 1051 fatal("%s: sshbuf_new failed", __func__); 1052 if ((r = sshbuf_put_stringb(m, conf)) != 0) 1053 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1054 1055 #ifdef WITH_SSH1 1056 if (sensitive_data.server_key != NULL && 1057 sensitive_data.server_key->type == KEY_RSA1) { 1058 if ((r = sshbuf_put_u32(m, 1)) != 0 || 1059 (r = sshbuf_put_bignum1(m, 1060 sensitive_data.server_key->rsa->e)) != 0 || 1061 (r = sshbuf_put_bignum1(m, 1062 sensitive_data.server_key->rsa->n)) != 0 || 1063 (r = sshbuf_put_bignum1(m, 1064 sensitive_data.server_key->rsa->d)) != 0 || 1065 (r = sshbuf_put_bignum1(m, 1066 sensitive_data.server_key->rsa->iqmp)) != 0 || 1067 (r = sshbuf_put_bignum1(m, 1068 sensitive_data.server_key->rsa->p)) != 0 || 1069 (r = sshbuf_put_bignum1(m, 1070 sensitive_data.server_key->rsa->q)) != 0) 1071 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1072 } else 1073 #endif 1074 if ((r = sshbuf_put_u32(m, 1)) != 0) 1075 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1076 1077 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 1078 rexec_send_rng_seed(m); 1079 #endif 1080 1081 if (ssh_msg_send(fd, 0, m) == -1) 1082 fatal("%s: ssh_msg_send failed", __func__); 1083 1084 sshbuf_free(m); 1085 1086 debug3("%s: done", __func__); 1087 } 1088 1089 static void 1090 recv_rexec_state(int fd, Buffer *conf) 1091 { 1092 Buffer m; 1093 char *cp; 1094 u_int len; 1095 1096 debug3("%s: entering fd = %d", __func__, fd); 1097 1098 buffer_init(&m); 1099 1100 if (ssh_msg_recv(fd, &m) == -1) 1101 fatal("%s: ssh_msg_recv failed", __func__); 1102 if (buffer_get_char(&m) != 0) 1103 fatal("%s: rexec version mismatch", __func__); 1104 1105 cp = buffer_get_string(&m, &len); 1106 if (conf != NULL) 1107 buffer_append(conf, cp, len); 1108 free(cp); 1109 1110 if (buffer_get_int(&m)) { 1111 #ifdef WITH_SSH1 1112 if (sensitive_data.server_key != NULL) 1113 key_free(sensitive_data.server_key); 1114 sensitive_data.server_key = key_new_private(KEY_RSA1); 1115 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); 1116 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); 1117 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); 1118 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); 1119 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); 1120 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); 1121 if (rsa_generate_additional_parameters( 1122 sensitive_data.server_key->rsa) != 0) 1123 fatal("%s: rsa_generate_additional_parameters " 1124 "error", __func__); 1125 #endif 1126 } 1127 1128 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 1129 rexec_recv_rng_seed(&m); 1130 #endif 1131 1132 buffer_free(&m); 1133 1134 debug3("%s: done", __func__); 1135 } 1136 1137 /* Accept a connection from inetd */ 1138 static void 1139 server_accept_inetd(int *sock_in, int *sock_out) 1140 { 1141 int fd; 1142 1143 startup_pipe = -1; 1144 if (rexeced_flag) { 1145 close(REEXEC_CONFIG_PASS_FD); 1146 *sock_in = *sock_out = dup(STDIN_FILENO); 1147 if (!debug_flag) { 1148 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); 1149 close(REEXEC_STARTUP_PIPE_FD); 1150 } 1151 } else { 1152 *sock_in = dup(STDIN_FILENO); 1153 *sock_out = dup(STDOUT_FILENO); 1154 } 1155 /* 1156 * We intentionally do not close the descriptors 0, 1, and 2 1157 * as our code for setting the descriptors won't work if 1158 * ttyfd happens to be one of those. 1159 */ 1160 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1161 dup2(fd, STDIN_FILENO); 1162 dup2(fd, STDOUT_FILENO); 1163 if (!log_stderr) 1164 dup2(fd, STDERR_FILENO); 1165 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO)) 1166 close(fd); 1167 } 1168 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); 1169 } 1170 1171 /* 1172 * Listen for TCP connections 1173 */ 1174 static void 1175 server_listen(void) 1176 { 1177 int ret, listen_sock, on = 1; 1178 struct addrinfo *ai; 1179 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 1180 1181 for (ai = options.listen_addrs; ai; ai = ai->ai_next) { 1182 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 1183 continue; 1184 if (num_listen_socks >= MAX_LISTEN_SOCKS) 1185 fatal("Too many listen sockets. " 1186 "Enlarge MAX_LISTEN_SOCKS"); 1187 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, 1188 ntop, sizeof(ntop), strport, sizeof(strport), 1189 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { 1190 error("getnameinfo failed: %.100s", 1191 ssh_gai_strerror(ret)); 1192 continue; 1193 } 1194 /* Create socket for listening. */ 1195 listen_sock = socket(ai->ai_family, ai->ai_socktype, 1196 ai->ai_protocol); 1197 if (listen_sock < 0) { 1198 /* kernel may not support ipv6 */ 1199 verbose("socket: %.100s", strerror(errno)); 1200 continue; 1201 } 1202 if (set_nonblock(listen_sock) == -1) { 1203 close(listen_sock); 1204 continue; 1205 } 1206 /* 1207 * Set socket options. 1208 * Allow local port reuse in TIME_WAIT. 1209 */ 1210 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, 1211 &on, sizeof(on)) == -1) 1212 error("setsockopt SO_REUSEADDR: %s", strerror(errno)); 1213 1214 /* Only communicate in IPv6 over AF_INET6 sockets. */ 1215 if (ai->ai_family == AF_INET6) 1216 sock_set_v6only(listen_sock); 1217 1218 debug("Bind to port %s on %s.", strport, ntop); 1219 1220 /* Bind the socket to the desired port. */ 1221 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1222 error("Bind to port %s on %s failed: %.200s.", 1223 strport, ntop, strerror(errno)); 1224 close(listen_sock); 1225 continue; 1226 } 1227 listen_socks[num_listen_socks] = listen_sock; 1228 num_listen_socks++; 1229 1230 /* Start listening on the port. */ 1231 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) 1232 fatal("listen on [%s]:%s: %.100s", 1233 ntop, strport, strerror(errno)); 1234 logit("Server listening on %s port %s.", ntop, strport); 1235 } 1236 freeaddrinfo(options.listen_addrs); 1237 1238 if (!num_listen_socks) 1239 fatal("Cannot bind any address."); 1240 } 1241 1242 /* 1243 * The main TCP accept loop. Note that, for the non-debug case, returns 1244 * from this function are in a forked subprocess. 1245 */ 1246 static void 1247 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) 1248 { 1249 fd_set *fdset; 1250 int i, j, ret, maxfd; 1251 int key_used = 0, startups = 0; 1252 int startup_p[2] = { -1 , -1 }; 1253 struct sockaddr_storage from; 1254 socklen_t fromlen; 1255 pid_t pid; 1256 u_char rnd[256]; 1257 1258 /* setup fd set for accept */ 1259 fdset = NULL; 1260 maxfd = 0; 1261 for (i = 0; i < num_listen_socks; i++) 1262 if (listen_socks[i] > maxfd) 1263 maxfd = listen_socks[i]; 1264 /* pipes connected to unauthenticated childs */ 1265 startup_pipes = xcalloc(options.max_startups, sizeof(int)); 1266 for (i = 0; i < options.max_startups; i++) 1267 startup_pipes[i] = -1; 1268 1269 /* 1270 * Stay listening for connections until the system crashes or 1271 * the daemon is killed with a signal. 1272 */ 1273 for (;;) { 1274 if (received_sighup) 1275 sighup_restart(); 1276 free(fdset); 1277 fdset = xcalloc(howmany(maxfd + 1, NFDBITS), 1278 sizeof(fd_mask)); 1279 1280 for (i = 0; i < num_listen_socks; i++) 1281 FD_SET(listen_socks[i], fdset); 1282 for (i = 0; i < options.max_startups; i++) 1283 if (startup_pipes[i] != -1) 1284 FD_SET(startup_pipes[i], fdset); 1285 1286 /* Wait in select until there is a connection. */ 1287 ret = select(maxfd+1, fdset, NULL, NULL, NULL); 1288 if (ret < 0 && errno != EINTR) 1289 error("select: %.100s", strerror(errno)); 1290 if (received_sigterm) { 1291 logit("Received signal %d; terminating.", 1292 (int) received_sigterm); 1293 close_listen_socks(); 1294 if (options.pid_file != NULL) 1295 unlink(options.pid_file); 1296 exit(received_sigterm == SIGTERM ? 0 : 255); 1297 } 1298 if (key_used && key_do_regen) { 1299 generate_ephemeral_server_key(); 1300 key_used = 0; 1301 key_do_regen = 0; 1302 } 1303 if (ret < 0) 1304 continue; 1305 1306 for (i = 0; i < options.max_startups; i++) 1307 if (startup_pipes[i] != -1 && 1308 FD_ISSET(startup_pipes[i], fdset)) { 1309 /* 1310 * the read end of the pipe is ready 1311 * if the child has closed the pipe 1312 * after successful authentication 1313 * or if the child has died 1314 */ 1315 close(startup_pipes[i]); 1316 startup_pipes[i] = -1; 1317 startups--; 1318 } 1319 for (i = 0; i < num_listen_socks; i++) { 1320 if (!FD_ISSET(listen_socks[i], fdset)) 1321 continue; 1322 fromlen = sizeof(from); 1323 *newsock = accept(listen_socks[i], 1324 (struct sockaddr *)&from, &fromlen); 1325 if (*newsock < 0) { 1326 if (errno != EINTR && errno != EWOULDBLOCK && 1327 errno != ECONNABORTED && errno != EAGAIN) 1328 error("accept: %.100s", 1329 strerror(errno)); 1330 if (errno == EMFILE || errno == ENFILE) 1331 usleep(100 * 1000); 1332 continue; 1333 } 1334 if (unset_nonblock(*newsock) == -1) { 1335 close(*newsock); 1336 continue; 1337 } 1338 if (drop_connection(startups) == 1) { 1339 debug("drop connection #%d", startups); 1340 close(*newsock); 1341 continue; 1342 } 1343 if (pipe(startup_p) == -1) { 1344 close(*newsock); 1345 continue; 1346 } 1347 1348 if (rexec_flag && socketpair(AF_UNIX, 1349 SOCK_STREAM, 0, config_s) == -1) { 1350 error("reexec socketpair: %s", 1351 strerror(errno)); 1352 close(*newsock); 1353 close(startup_p[0]); 1354 close(startup_p[1]); 1355 continue; 1356 } 1357 1358 for (j = 0; j < options.max_startups; j++) 1359 if (startup_pipes[j] == -1) { 1360 startup_pipes[j] = startup_p[0]; 1361 if (maxfd < startup_p[0]) 1362 maxfd = startup_p[0]; 1363 startups++; 1364 break; 1365 } 1366 1367 /* 1368 * Got connection. Fork a child to handle it, unless 1369 * we are in debugging mode. 1370 */ 1371 if (debug_flag) { 1372 /* 1373 * In debugging mode. Close the listening 1374 * socket, and start processing the 1375 * connection without forking. 1376 */ 1377 debug("Server will not fork when running in debugging mode."); 1378 close_listen_socks(); 1379 *sock_in = *newsock; 1380 *sock_out = *newsock; 1381 close(startup_p[0]); 1382 close(startup_p[1]); 1383 startup_pipe = -1; 1384 pid = getpid(); 1385 if (rexec_flag) { 1386 send_rexec_state(config_s[0], 1387 &cfg); 1388 close(config_s[0]); 1389 } 1390 break; 1391 } 1392 1393 /* 1394 * Normal production daemon. Fork, and have 1395 * the child process the connection. The 1396 * parent continues listening. 1397 */ 1398 platform_pre_fork(); 1399 if ((pid = fork()) == 0) { 1400 /* 1401 * Child. Close the listening and 1402 * max_startup sockets. Start using 1403 * the accepted socket. Reinitialize 1404 * logging (since our pid has changed). 1405 * We break out of the loop to handle 1406 * the connection. 1407 */ 1408 platform_post_fork_child(); 1409 startup_pipe = startup_p[1]; 1410 close_startup_pipes(); 1411 close_listen_socks(); 1412 *sock_in = *newsock; 1413 *sock_out = *newsock; 1414 log_init(__progname, 1415 options.log_level, 1416 options.log_facility, 1417 log_stderr); 1418 if (rexec_flag) 1419 close(config_s[0]); 1420 break; 1421 } 1422 1423 /* Parent. Stay in the loop. */ 1424 platform_post_fork_parent(pid); 1425 if (pid < 0) 1426 error("fork: %.100s", strerror(errno)); 1427 else 1428 debug("Forked child %ld.", (long)pid); 1429 1430 close(startup_p[1]); 1431 1432 if (rexec_flag) { 1433 send_rexec_state(config_s[0], &cfg); 1434 close(config_s[0]); 1435 close(config_s[1]); 1436 } 1437 1438 /* 1439 * Mark that the key has been used (it 1440 * was "given" to the child). 1441 */ 1442 if ((options.protocol & SSH_PROTO_1) && 1443 key_used == 0) { 1444 /* Schedule server key regeneration alarm. */ 1445 signal(SIGALRM, key_regeneration_alarm); 1446 alarm(options.key_regeneration_time); 1447 key_used = 1; 1448 } 1449 1450 close(*newsock); 1451 1452 /* 1453 * Ensure that our random state differs 1454 * from that of the child 1455 */ 1456 arc4random_stir(); 1457 arc4random_buf(rnd, sizeof(rnd)); 1458 #ifdef WITH_OPENSSL 1459 RAND_seed(rnd, sizeof(rnd)); 1460 if ((RAND_bytes((u_char *)rnd, 1)) != 1) 1461 fatal("%s: RAND_bytes failed", __func__); 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 * If IP options are supported, make sure there are none (log and 1474 * return an error if any are found). Basically we are worried about 1475 * source routing; it can be used to pretend you are somebody 1476 * (ip-address) you are not. That itself may be "almost acceptable" 1477 * under certain circumstances, but rhosts autentication is useless 1478 * if source routing is accepted. Notice also that if we just dropped 1479 * source routing here, the other side could use IP spoofing to do 1480 * rest of the interaction and could still bypass security. So we 1481 * exit here if we detect any IP options. 1482 */ 1483 static void 1484 check_ip_options(struct ssh *ssh) 1485 { 1486 #ifdef IP_OPTIONS 1487 int sock_in = ssh_packet_get_connection_in(ssh); 1488 struct sockaddr_storage from; 1489 socklen_t option_size, i, fromlen = sizeof(from); 1490 u_char opts[200]; 1491 char text[sizeof(opts) * 3 + 1]; 1492 1493 memset(&from, 0, sizeof(from)); 1494 if (getpeername(sock_in, (struct sockaddr *)&from, 1495 &fromlen) < 0) 1496 return; 1497 if (from.ss_family != AF_INET) 1498 return; 1499 /* XXX IPv6 options? */ 1500 1501 if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts, 1502 &option_size) >= 0 && option_size != 0) { 1503 text[0] = '\0'; 1504 for (i = 0; i < option_size; i++) 1505 snprintf(text + i*3, sizeof(text) - i*3, 1506 " %2.2x", opts[i]); 1507 fatal("Connection from %.100s port %d with IP opts: %.800s", 1508 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text); 1509 } 1510 return; 1511 #endif /* IP_OPTIONS */ 1512 } 1513 1514 /* 1515 * Main program for the daemon. 1516 */ 1517 int 1518 main(int ac, char **av) 1519 { 1520 struct ssh *ssh = NULL; 1521 extern char *optarg; 1522 extern int optind; 1523 int r, opt, i, j, on = 1; 1524 int sock_in = -1, sock_out = -1, newsock = -1; 1525 const char *remote_ip; 1526 int remote_port; 1527 char *fp, *line, *laddr, *logfile = NULL; 1528 int config_s[2] = { -1 , -1 }; 1529 u_int n; 1530 u_int64_t ibytes, obytes; 1531 mode_t new_umask; 1532 Key *key; 1533 Key *pubkey; 1534 int keytype; 1535 Authctxt *authctxt; 1536 struct connection_info *connection_info = get_connection_info(0, 0); 1537 1538 ssh_malloc_init(); /* must be called before any mallocs */ 1539 1540 #ifdef HAVE_SECUREWARE 1541 (void)set_auth_parameters(ac, av); 1542 #endif 1543 __progname = ssh_get_progname(av[0]); 1544 1545 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ 1546 saved_argc = ac; 1547 rexec_argc = ac; 1548 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); 1549 for (i = 0; i < ac; i++) 1550 saved_argv[i] = xstrdup(av[i]); 1551 saved_argv[i] = NULL; 1552 1553 #ifndef HAVE_SETPROCTITLE 1554 /* Prepare for later setproctitle emulation */ 1555 compat_init_setproctitle(ac, av); 1556 av = saved_argv; 1557 #endif 1558 1559 if (geteuid() == 0 && setgroups(0, NULL) == -1) 1560 debug("setgroups(): %.200s", strerror(errno)); 1561 1562 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1563 sanitise_stdfd(); 1564 1565 /* Initialize configuration options to their default values. */ 1566 initialize_server_options(&options); 1567 1568 /* Parse command-line arguments. */ 1569 while ((opt = getopt(ac, av, 1570 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) { 1571 switch (opt) { 1572 case '4': 1573 options.address_family = AF_INET; 1574 break; 1575 case '6': 1576 options.address_family = AF_INET6; 1577 break; 1578 case 'f': 1579 config_file_name = optarg; 1580 break; 1581 case 'c': 1582 if (options.num_host_cert_files >= MAX_HOSTCERTS) { 1583 fprintf(stderr, "too many host certificates.\n"); 1584 exit(1); 1585 } 1586 options.host_cert_files[options.num_host_cert_files++] = 1587 derelativise_path(optarg); 1588 break; 1589 case 'd': 1590 if (debug_flag == 0) { 1591 debug_flag = 1; 1592 options.log_level = SYSLOG_LEVEL_DEBUG1; 1593 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) 1594 options.log_level++; 1595 break; 1596 case 'D': 1597 no_daemon_flag = 1; 1598 break; 1599 case 'E': 1600 logfile = optarg; 1601 /* FALLTHROUGH */ 1602 case 'e': 1603 log_stderr = 1; 1604 break; 1605 case 'i': 1606 inetd_flag = 1; 1607 break; 1608 case 'r': 1609 rexec_flag = 0; 1610 break; 1611 case 'R': 1612 rexeced_flag = 1; 1613 inetd_flag = 1; 1614 break; 1615 case 'Q': 1616 /* ignored */ 1617 break; 1618 case 'q': 1619 options.log_level = SYSLOG_LEVEL_QUIET; 1620 break; 1621 case 'b': 1622 options.server_key_bits = (int)strtonum(optarg, 256, 1623 32768, NULL); 1624 break; 1625 case 'p': 1626 options.ports_from_cmdline = 1; 1627 if (options.num_ports >= MAX_PORTS) { 1628 fprintf(stderr, "too many ports.\n"); 1629 exit(1); 1630 } 1631 options.ports[options.num_ports++] = a2port(optarg); 1632 if (options.ports[options.num_ports-1] <= 0) { 1633 fprintf(stderr, "Bad port number.\n"); 1634 exit(1); 1635 } 1636 break; 1637 case 'g': 1638 if ((options.login_grace_time = convtime(optarg)) == -1) { 1639 fprintf(stderr, "Invalid login grace time.\n"); 1640 exit(1); 1641 } 1642 break; 1643 case 'k': 1644 if ((options.key_regeneration_time = convtime(optarg)) == -1) { 1645 fprintf(stderr, "Invalid key regeneration interval.\n"); 1646 exit(1); 1647 } 1648 break; 1649 case 'h': 1650 if (options.num_host_key_files >= MAX_HOSTKEYS) { 1651 fprintf(stderr, "too many host keys.\n"); 1652 exit(1); 1653 } 1654 options.host_key_files[options.num_host_key_files++] = 1655 derelativise_path(optarg); 1656 break; 1657 case 't': 1658 test_flag = 1; 1659 break; 1660 case 'T': 1661 test_flag = 2; 1662 break; 1663 case 'C': 1664 if (parse_server_match_testspec(connection_info, 1665 optarg) == -1) 1666 exit(1); 1667 break; 1668 case 'u': 1669 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL); 1670 if (utmp_len > HOST_NAME_MAX+1) { 1671 fprintf(stderr, "Invalid utmp length.\n"); 1672 exit(1); 1673 } 1674 break; 1675 case 'o': 1676 line = xstrdup(optarg); 1677 if (process_server_config_line(&options, line, 1678 "command-line", 0, NULL, NULL) != 0) 1679 exit(1); 1680 free(line); 1681 break; 1682 case '?': 1683 default: 1684 usage(); 1685 break; 1686 } 1687 } 1688 if (rexeced_flag || inetd_flag) 1689 rexec_flag = 0; 1690 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) 1691 fatal("sshd re-exec requires execution with an absolute path"); 1692 if (rexeced_flag) 1693 closefrom(REEXEC_MIN_FREE_FD); 1694 else 1695 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); 1696 1697 #ifdef WITH_OPENSSL 1698 OpenSSL_add_all_algorithms(); 1699 #endif 1700 1701 /* If requested, redirect the logs to the specified logfile. */ 1702 if (logfile != NULL) 1703 log_redirect_stderr_to(logfile); 1704 /* 1705 * Force logging to stderr until we have loaded the private host 1706 * key (unless started from inetd) 1707 */ 1708 log_init(__progname, 1709 options.log_level == SYSLOG_LEVEL_NOT_SET ? 1710 SYSLOG_LEVEL_INFO : options.log_level, 1711 options.log_facility == SYSLOG_FACILITY_NOT_SET ? 1712 SYSLOG_FACILITY_AUTH : options.log_facility, 1713 log_stderr || !inetd_flag); 1714 1715 /* 1716 * Unset KRB5CCNAME, otherwise the user's session may inherit it from 1717 * root's environment 1718 */ 1719 if (getenv("KRB5CCNAME") != NULL) 1720 (void) unsetenv("KRB5CCNAME"); 1721 1722 #ifdef _UNICOS 1723 /* Cray can define user privs drop all privs now! 1724 * Not needed on PRIV_SU systems! 1725 */ 1726 drop_cray_privs(); 1727 #endif 1728 1729 sensitive_data.server_key = NULL; 1730 sensitive_data.ssh1_host_key = NULL; 1731 sensitive_data.have_ssh1_key = 0; 1732 sensitive_data.have_ssh2_key = 0; 1733 1734 /* 1735 * If we're doing an extended config test, make sure we have all of 1736 * the parameters we need. If we're not doing an extended test, 1737 * do not silently ignore connection test params. 1738 */ 1739 if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0) 1740 fatal("user, host and addr are all required when testing " 1741 "Match configs"); 1742 if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0) 1743 fatal("Config test connection parameter (-C) provided without " 1744 "test mode (-T)"); 1745 1746 /* Fetch our configuration */ 1747 buffer_init(&cfg); 1748 if (rexeced_flag) 1749 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); 1750 else if (strcasecmp(config_file_name, "none") != 0) 1751 load_server_config(config_file_name, &cfg); 1752 1753 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, 1754 &cfg, NULL); 1755 1756 seed_rng(); 1757 1758 /* Fill in default values for those options not explicitly set. */ 1759 fill_default_server_options(&options); 1760 1761 /* challenge-response is implemented via keyboard interactive */ 1762 if (options.challenge_response_authentication) 1763 options.kbd_interactive_authentication = 1; 1764 1765 /* Check that options are sensible */ 1766 if (options.authorized_keys_command_user == NULL && 1767 (options.authorized_keys_command != NULL && 1768 strcasecmp(options.authorized_keys_command, "none") != 0)) 1769 fatal("AuthorizedKeysCommand set without " 1770 "AuthorizedKeysCommandUser"); 1771 if (options.authorized_principals_command_user == NULL && 1772 (options.authorized_principals_command != NULL && 1773 strcasecmp(options.authorized_principals_command, "none") != 0)) 1774 fatal("AuthorizedPrincipalsCommand set without " 1775 "AuthorizedPrincipalsCommandUser"); 1776 1777 /* 1778 * Check whether there is any path through configured auth methods. 1779 * Unfortunately it is not possible to verify this generally before 1780 * daemonisation in the presence of Match block, but this catches 1781 * and warns for trivial misconfigurations that could break login. 1782 */ 1783 if (options.num_auth_methods != 0) { 1784 if ((options.protocol & SSH_PROTO_1)) 1785 fatal("AuthenticationMethods is not supported with " 1786 "SSH protocol 1"); 1787 for (n = 0; n < options.num_auth_methods; n++) { 1788 if (auth2_methods_valid(options.auth_methods[n], 1789 1) == 0) 1790 break; 1791 } 1792 if (n >= options.num_auth_methods) 1793 fatal("AuthenticationMethods cannot be satisfied by " 1794 "enabled authentication methods"); 1795 } 1796 1797 /* set default channel AF */ 1798 channel_set_af(options.address_family); 1799 1800 /* Check that there are no remaining arguments. */ 1801 if (optind < ac) { 1802 fprintf(stderr, "Extra argument %s.\n", av[optind]); 1803 exit(1); 1804 } 1805 1806 debug("sshd version %s, %s", SSH_VERSION, 1807 #ifdef WITH_OPENSSL 1808 SSLeay_version(SSLEAY_VERSION) 1809 #else 1810 "without OpenSSL" 1811 #endif 1812 ); 1813 1814 /* Store privilege separation user for later use if required. */ 1815 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { 1816 if (use_privsep || options.kerberos_authentication) 1817 fatal("Privilege separation user %s does not exist", 1818 SSH_PRIVSEP_USER); 1819 } else { 1820 explicit_bzero(privsep_pw->pw_passwd, 1821 strlen(privsep_pw->pw_passwd)); 1822 privsep_pw = pwcopy(privsep_pw); 1823 free(privsep_pw->pw_passwd); 1824 privsep_pw->pw_passwd = xstrdup("*"); 1825 } 1826 endpwent(); 1827 1828 /* load host keys */ 1829 sensitive_data.host_keys = xcalloc(options.num_host_key_files, 1830 sizeof(Key *)); 1831 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files, 1832 sizeof(Key *)); 1833 1834 if (options.host_key_agent) { 1835 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME)) 1836 setenv(SSH_AUTHSOCKET_ENV_NAME, 1837 options.host_key_agent, 1); 1838 if ((r = ssh_get_authentication_socket(NULL)) == 0) 1839 have_agent = 1; 1840 else 1841 error("Could not connect to agent \"%s\": %s", 1842 options.host_key_agent, ssh_err(r)); 1843 } 1844 1845 for (i = 0; i < options.num_host_key_files; i++) { 1846 if (options.host_key_files[i] == NULL) 1847 continue; 1848 key = key_load_private(options.host_key_files[i], "", NULL); 1849 pubkey = key_load_public(options.host_key_files[i], NULL); 1850 if (pubkey == NULL && key != NULL) 1851 pubkey = key_demote(key); 1852 sensitive_data.host_keys[i] = key; 1853 sensitive_data.host_pubkeys[i] = pubkey; 1854 1855 if (key == NULL && pubkey != NULL && pubkey->type != KEY_RSA1 && 1856 have_agent) { 1857 debug("will rely on agent for hostkey %s", 1858 options.host_key_files[i]); 1859 keytype = pubkey->type; 1860 } else if (key != NULL) { 1861 keytype = key->type; 1862 } else { 1863 error("Could not load host key: %s", 1864 options.host_key_files[i]); 1865 sensitive_data.host_keys[i] = NULL; 1866 sensitive_data.host_pubkeys[i] = NULL; 1867 continue; 1868 } 1869 1870 switch (keytype) { 1871 case KEY_RSA1: 1872 sensitive_data.ssh1_host_key = key; 1873 sensitive_data.have_ssh1_key = 1; 1874 break; 1875 case KEY_RSA: 1876 case KEY_DSA: 1877 case KEY_ECDSA: 1878 case KEY_ED25519: 1879 if (have_agent || key != NULL) 1880 sensitive_data.have_ssh2_key = 1; 1881 break; 1882 } 1883 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash, 1884 SSH_FP_DEFAULT)) == NULL) 1885 fatal("sshkey_fingerprint failed"); 1886 debug("%s host key #%d: %s %s", 1887 key ? "private" : "agent", i, keytype == KEY_RSA1 ? 1888 sshkey_type(pubkey) : sshkey_ssh_name(pubkey), fp); 1889 free(fp); 1890 } 1891 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { 1892 logit("Disabling protocol version 1. Could not load host key"); 1893 options.protocol &= ~SSH_PROTO_1; 1894 } 1895 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { 1896 logit("Disabling protocol version 2. Could not load host key"); 1897 options.protocol &= ~SSH_PROTO_2; 1898 } 1899 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { 1900 logit("sshd: no hostkeys available -- exiting."); 1901 exit(1); 1902 } 1903 1904 /* 1905 * Load certificates. They are stored in an array at identical 1906 * indices to the public keys that they relate to. 1907 */ 1908 sensitive_data.host_certificates = xcalloc(options.num_host_key_files, 1909 sizeof(Key *)); 1910 for (i = 0; i < options.num_host_key_files; i++) 1911 sensitive_data.host_certificates[i] = NULL; 1912 1913 for (i = 0; i < options.num_host_cert_files; i++) { 1914 if (options.host_cert_files[i] == NULL) 1915 continue; 1916 key = key_load_public(options.host_cert_files[i], NULL); 1917 if (key == NULL) { 1918 error("Could not load host certificate: %s", 1919 options.host_cert_files[i]); 1920 continue; 1921 } 1922 if (!key_is_cert(key)) { 1923 error("Certificate file is not a certificate: %s", 1924 options.host_cert_files[i]); 1925 key_free(key); 1926 continue; 1927 } 1928 /* Find matching private key */ 1929 for (j = 0; j < options.num_host_key_files; j++) { 1930 if (key_equal_public(key, 1931 sensitive_data.host_keys[j])) { 1932 sensitive_data.host_certificates[j] = key; 1933 break; 1934 } 1935 } 1936 if (j >= options.num_host_key_files) { 1937 error("No matching private key for certificate: %s", 1938 options.host_cert_files[i]); 1939 key_free(key); 1940 continue; 1941 } 1942 sensitive_data.host_certificates[j] = key; 1943 debug("host certificate: #%d type %d %s", j, key->type, 1944 key_type(key)); 1945 } 1946 1947 #ifdef WITH_SSH1 1948 /* Check certain values for sanity. */ 1949 if (options.protocol & SSH_PROTO_1) { 1950 if (options.server_key_bits < SSH_RSA_MINIMUM_MODULUS_SIZE || 1951 options.server_key_bits > OPENSSL_RSA_MAX_MODULUS_BITS) { 1952 fprintf(stderr, "Bad server key size.\n"); 1953 exit(1); 1954 } 1955 /* 1956 * Check that server and host key lengths differ sufficiently. This 1957 * is necessary to make double encryption work with rsaref. Oh, I 1958 * hate software patents. I dont know if this can go? Niels 1959 */ 1960 if (options.server_key_bits > 1961 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - 1962 SSH_KEY_BITS_RESERVED && options.server_key_bits < 1963 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1964 SSH_KEY_BITS_RESERVED) { 1965 options.server_key_bits = 1966 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1967 SSH_KEY_BITS_RESERVED; 1968 debug("Forcing server key to %d bits to make it differ from host key.", 1969 options.server_key_bits); 1970 } 1971 } 1972 #endif 1973 1974 if (use_privsep) { 1975 struct stat st; 1976 1977 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || 1978 (S_ISDIR(st.st_mode) == 0)) 1979 fatal("Missing privilege separation directory: %s", 1980 _PATH_PRIVSEP_CHROOT_DIR); 1981 1982 #ifdef HAVE_CYGWIN 1983 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && 1984 (st.st_uid != getuid () || 1985 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) 1986 #else 1987 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) 1988 #endif 1989 fatal("%s must be owned by root and not group or " 1990 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); 1991 } 1992 1993 if (test_flag > 1) { 1994 if (server_match_spec_complete(connection_info) == 1) 1995 parse_server_match_config(&options, connection_info); 1996 dump_config(&options); 1997 } 1998 1999 /* Configuration looks good, so exit if in test mode. */ 2000 if (test_flag) 2001 exit(0); 2002 2003 /* 2004 * Clear out any supplemental groups we may have inherited. This 2005 * prevents inadvertent creation of files with bad modes (in the 2006 * portable version at least, it's certainly possible for PAM 2007 * to create a file, and we can't control the code in every 2008 * module which might be used). 2009 */ 2010 if (setgroups(0, NULL) < 0) 2011 debug("setgroups() failed: %.200s", strerror(errno)); 2012 2013 if (rexec_flag) { 2014 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); 2015 for (i = 0; i < rexec_argc; i++) { 2016 debug("rexec_argv[%d]='%s'", i, saved_argv[i]); 2017 rexec_argv[i] = saved_argv[i]; 2018 } 2019 rexec_argv[rexec_argc] = "-R"; 2020 rexec_argv[rexec_argc + 1] = NULL; 2021 } 2022 2023 /* Ensure that umask disallows at least group and world write */ 2024 new_umask = umask(0077) | 0022; 2025 (void) umask(new_umask); 2026 2027 /* Initialize the log (it is reinitialized below in case we forked). */ 2028 if (debug_flag && (!inetd_flag || rexeced_flag)) 2029 log_stderr = 1; 2030 log_init(__progname, options.log_level, options.log_facility, log_stderr); 2031 2032 /* 2033 * If not in debugging mode, and not started from inetd, disconnect 2034 * from the controlling terminal, and fork. The original process 2035 * exits. 2036 */ 2037 if (!(debug_flag || inetd_flag || no_daemon_flag)) { 2038 #ifdef TIOCNOTTY 2039 int fd; 2040 #endif /* TIOCNOTTY */ 2041 if (daemon(0, 0) < 0) 2042 fatal("daemon() failed: %.200s", strerror(errno)); 2043 2044 /* Disconnect from the controlling tty. */ 2045 #ifdef TIOCNOTTY 2046 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); 2047 if (fd >= 0) { 2048 (void) ioctl(fd, TIOCNOTTY, NULL); 2049 close(fd); 2050 } 2051 #endif /* TIOCNOTTY */ 2052 } 2053 /* Reinitialize the log (because of the fork above). */ 2054 log_init(__progname, options.log_level, options.log_facility, log_stderr); 2055 2056 /* Chdir to the root directory so that the current disk can be 2057 unmounted if desired. */ 2058 if (chdir("/") == -1) 2059 error("chdir(\"/\"): %s", strerror(errno)); 2060 2061 /* ignore SIGPIPE */ 2062 signal(SIGPIPE, SIG_IGN); 2063 2064 /* Get a connection, either from inetd or a listening TCP socket */ 2065 if (inetd_flag) { 2066 server_accept_inetd(&sock_in, &sock_out); 2067 } else { 2068 platform_pre_listen(); 2069 server_listen(); 2070 2071 if (options.protocol & SSH_PROTO_1) 2072 generate_ephemeral_server_key(); 2073 2074 signal(SIGHUP, sighup_handler); 2075 signal(SIGCHLD, main_sigchld_handler); 2076 signal(SIGTERM, sigterm_handler); 2077 signal(SIGQUIT, sigterm_handler); 2078 2079 /* 2080 * Write out the pid file after the sigterm handler 2081 * is setup and the listen sockets are bound 2082 */ 2083 if (options.pid_file != NULL && !debug_flag) { 2084 FILE *f = fopen(options.pid_file, "w"); 2085 2086 if (f == NULL) { 2087 error("Couldn't create pid file \"%s\": %s", 2088 options.pid_file, strerror(errno)); 2089 } else { 2090 fprintf(f, "%ld\n", (long) getpid()); 2091 fclose(f); 2092 } 2093 } 2094 2095 /* Accept a connection and return in a forked child */ 2096 server_accept_loop(&sock_in, &sock_out, 2097 &newsock, config_s); 2098 } 2099 2100 /* This is the child processing a new connection. */ 2101 setproctitle("%s", "[accepted]"); 2102 2103 /* 2104 * Create a new session and process group since the 4.4BSD 2105 * setlogin() affects the entire process group. We don't 2106 * want the child to be able to affect the parent. 2107 */ 2108 #if !defined(SSHD_ACQUIRES_CTTY) 2109 /* 2110 * If setsid is called, on some platforms sshd will later acquire a 2111 * controlling terminal which will result in "could not set 2112 * controlling tty" errors. 2113 */ 2114 if (!debug_flag && !inetd_flag && setsid() < 0) 2115 error("setsid: %.100s", strerror(errno)); 2116 #endif 2117 2118 if (rexec_flag) { 2119 int fd; 2120 2121 debug("rexec start in %d out %d newsock %d pipe %d sock %d", 2122 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 2123 dup2(newsock, STDIN_FILENO); 2124 dup2(STDIN_FILENO, STDOUT_FILENO); 2125 if (startup_pipe == -1) 2126 close(REEXEC_STARTUP_PIPE_FD); 2127 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) { 2128 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); 2129 close(startup_pipe); 2130 startup_pipe = REEXEC_STARTUP_PIPE_FD; 2131 } 2132 2133 dup2(config_s[1], REEXEC_CONFIG_PASS_FD); 2134 close(config_s[1]); 2135 2136 execv(rexec_argv[0], rexec_argv); 2137 2138 /* Reexec has failed, fall back and continue */ 2139 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); 2140 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); 2141 log_init(__progname, options.log_level, 2142 options.log_facility, log_stderr); 2143 2144 /* Clean up fds */ 2145 close(REEXEC_CONFIG_PASS_FD); 2146 newsock = sock_out = sock_in = dup(STDIN_FILENO); 2147 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 2148 dup2(fd, STDIN_FILENO); 2149 dup2(fd, STDOUT_FILENO); 2150 if (fd > STDERR_FILENO) 2151 close(fd); 2152 } 2153 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", 2154 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 2155 } 2156 2157 /* Executed child processes don't need these. */ 2158 fcntl(sock_out, F_SETFD, FD_CLOEXEC); 2159 fcntl(sock_in, F_SETFD, FD_CLOEXEC); 2160 2161 /* 2162 * Disable the key regeneration alarm. We will not regenerate the 2163 * key since we are no longer in a position to give it to anyone. We 2164 * will not restart on SIGHUP since it no longer makes sense. 2165 */ 2166 alarm(0); 2167 signal(SIGALRM, SIG_DFL); 2168 signal(SIGHUP, SIG_DFL); 2169 signal(SIGTERM, SIG_DFL); 2170 signal(SIGQUIT, SIG_DFL); 2171 signal(SIGCHLD, SIG_DFL); 2172 signal(SIGINT, SIG_DFL); 2173 2174 /* 2175 * Register our connection. This turns encryption off because we do 2176 * not have a key. 2177 */ 2178 packet_set_connection(sock_in, sock_out); 2179 packet_set_server(); 2180 ssh = active_state; /* XXX */ 2181 check_ip_options(ssh); 2182 2183 /* Set SO_KEEPALIVE if requested. */ 2184 if (options.tcp_keep_alive && packet_connection_is_on_socket() && 2185 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) 2186 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 2187 2188 if ((remote_port = ssh_remote_port(ssh)) < 0) { 2189 debug("ssh_remote_port failed"); 2190 cleanup_exit(255); 2191 } 2192 2193 /* 2194 * The rest of the code depends on the fact that 2195 * ssh_remote_ipaddr() caches the remote ip, even if 2196 * the socket goes away. 2197 */ 2198 remote_ip = ssh_remote_ipaddr(ssh); 2199 2200 #ifdef SSH_AUDIT_EVENTS 2201 audit_connection_from(remote_ip, remote_port); 2202 #endif 2203 2204 /* Log the connection. */ 2205 laddr = get_local_ipaddr(sock_in); 2206 verbose("Connection from %s port %d on %s port %d", 2207 remote_ip, remote_port, laddr, ssh_local_port(ssh)); 2208 free(laddr); 2209 2210 /* 2211 * We don't want to listen forever unless the other side 2212 * successfully authenticates itself. So we set up an alarm which is 2213 * cleared after successful authentication. A limit of zero 2214 * indicates no limit. Note that we don't set the alarm in debugging 2215 * mode; it is just annoying to have the server exit just when you 2216 * are about to discover the bug. 2217 */ 2218 signal(SIGALRM, grace_alarm_handler); 2219 if (!debug_flag) 2220 alarm(options.login_grace_time); 2221 2222 sshd_exchange_identification(ssh, sock_in, sock_out); 2223 2224 /* In inetd mode, generate ephemeral key only for proto 1 connections */ 2225 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) 2226 generate_ephemeral_server_key(); 2227 2228 packet_set_nonblocking(); 2229 2230 /* allocate authentication context */ 2231 authctxt = xcalloc(1, sizeof(*authctxt)); 2232 2233 authctxt->loginmsg = &loginmsg; 2234 2235 /* XXX global for cleanup, access from other modules */ 2236 the_authctxt = authctxt; 2237 2238 /* prepare buffer to collect messages to display to user after login */ 2239 buffer_init(&loginmsg); 2240 auth_debug_reset(); 2241 2242 if (use_privsep) { 2243 if (privsep_preauth(authctxt) == 1) 2244 goto authenticated; 2245 } else if (compat20 && have_agent) { 2246 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { 2247 error("Unable to get agent socket: %s", ssh_err(r)); 2248 have_agent = 0; 2249 } 2250 } 2251 2252 /* perform the key exchange */ 2253 /* authenticate user and start session */ 2254 if (compat20) { 2255 do_ssh2_kex(); 2256 do_authentication2(authctxt); 2257 } else { 2258 #ifdef WITH_SSH1 2259 do_ssh1_kex(); 2260 do_authentication(authctxt); 2261 #else 2262 fatal("ssh1 not supported"); 2263 #endif 2264 } 2265 /* 2266 * If we use privilege separation, the unprivileged child transfers 2267 * the current keystate and exits 2268 */ 2269 if (use_privsep) { 2270 mm_send_keystate(pmonitor); 2271 exit(0); 2272 } 2273 2274 authenticated: 2275 /* 2276 * Cancel the alarm we set to limit the time taken for 2277 * authentication. 2278 */ 2279 alarm(0); 2280 signal(SIGALRM, SIG_DFL); 2281 authctxt->authenticated = 1; 2282 if (startup_pipe != -1) { 2283 close(startup_pipe); 2284 startup_pipe = -1; 2285 } 2286 2287 #ifdef SSH_AUDIT_EVENTS 2288 audit_event(SSH_AUTH_SUCCESS); 2289 #endif 2290 2291 #ifdef GSSAPI 2292 if (options.gss_authentication) { 2293 temporarily_use_uid(authctxt->pw); 2294 ssh_gssapi_storecreds(); 2295 restore_uid(); 2296 } 2297 #endif 2298 #ifdef USE_PAM 2299 if (options.use_pam) { 2300 do_pam_setcred(1); 2301 do_pam_session(); 2302 } 2303 #endif 2304 2305 /* 2306 * In privilege separation, we fork another child and prepare 2307 * file descriptor passing. 2308 */ 2309 if (use_privsep) { 2310 privsep_postauth(authctxt); 2311 /* the monitor process [priv] will not return */ 2312 if (!compat20) 2313 destroy_sensitive_data(); 2314 } 2315 2316 packet_set_timeout(options.client_alive_interval, 2317 options.client_alive_count_max); 2318 2319 /* Try to send all our hostkeys to the client */ 2320 if (compat20) 2321 notify_hostkeys(active_state); 2322 2323 /* Start session. */ 2324 do_authenticated(authctxt); 2325 2326 /* The connection has been terminated. */ 2327 packet_get_bytes(&ibytes, &obytes); 2328 verbose("Transferred: sent %llu, received %llu bytes", 2329 (unsigned long long)obytes, (unsigned long long)ibytes); 2330 2331 verbose("Closing connection to %.500s port %d", remote_ip, remote_port); 2332 2333 #ifdef USE_PAM 2334 if (options.use_pam) 2335 finish_pam(); 2336 #endif /* USE_PAM */ 2337 2338 #ifdef SSH_AUDIT_EVENTS 2339 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); 2340 #endif 2341 2342 packet_close(); 2343 2344 if (use_privsep) 2345 mm_terminate(); 2346 2347 exit(0); 2348 } 2349 2350 #ifdef WITH_SSH1 2351 /* 2352 * Decrypt session_key_int using our private server key and private host key 2353 * (key with larger modulus first). 2354 */ 2355 int 2356 ssh1_session_key(BIGNUM *session_key_int) 2357 { 2358 struct ssh *ssh = active_state; /* XXX */ 2359 int rsafail = 0; 2360 2361 if (BN_cmp(sensitive_data.server_key->rsa->n, 2362 sensitive_data.ssh1_host_key->rsa->n) > 0) { 2363 /* Server key has bigger modulus. */ 2364 if (BN_num_bits(sensitive_data.server_key->rsa->n) < 2365 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 2366 SSH_KEY_BITS_RESERVED) { 2367 fatal("do_connection: %s port %d: " 2368 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", 2369 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 2370 BN_num_bits(sensitive_data.server_key->rsa->n), 2371 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 2372 SSH_KEY_BITS_RESERVED); 2373 } 2374 if (rsa_private_decrypt(session_key_int, session_key_int, 2375 sensitive_data.server_key->rsa) != 0) 2376 rsafail++; 2377 if (rsa_private_decrypt(session_key_int, session_key_int, 2378 sensitive_data.ssh1_host_key->rsa) != 0) 2379 rsafail++; 2380 } else { 2381 /* Host key has bigger modulus (or they are equal). */ 2382 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < 2383 BN_num_bits(sensitive_data.server_key->rsa->n) + 2384 SSH_KEY_BITS_RESERVED) { 2385 fatal("do_connection: %s port %d: " 2386 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", 2387 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 2388 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 2389 BN_num_bits(sensitive_data.server_key->rsa->n), 2390 SSH_KEY_BITS_RESERVED); 2391 } 2392 if (rsa_private_decrypt(session_key_int, session_key_int, 2393 sensitive_data.ssh1_host_key->rsa) != 0) 2394 rsafail++; 2395 if (rsa_private_decrypt(session_key_int, session_key_int, 2396 sensitive_data.server_key->rsa) != 0) 2397 rsafail++; 2398 } 2399 return (rsafail); 2400 } 2401 2402 /* 2403 * SSH1 key exchange 2404 */ 2405 static void 2406 do_ssh1_kex(void) 2407 { 2408 struct ssh *ssh = active_state; /* XXX */ 2409 int i, len; 2410 int rsafail = 0; 2411 BIGNUM *session_key_int, *fake_key_int, *real_key_int; 2412 u_char session_key[SSH_SESSION_KEY_LENGTH]; 2413 u_char fake_key_bytes[4096 / 8]; 2414 size_t fake_key_len; 2415 u_char cookie[8]; 2416 u_int cipher_type, auth_mask, protocol_flags; 2417 2418 /* 2419 * Generate check bytes that the client must send back in the user 2420 * packet in order for it to be accepted; this is used to defy ip 2421 * spoofing attacks. Note that this only works against somebody 2422 * doing IP spoofing from a remote machine; any machine on the local 2423 * network can still see outgoing packets and catch the random 2424 * cookie. This only affects rhosts authentication, and this is one 2425 * of the reasons why it is inherently insecure. 2426 */ 2427 arc4random_buf(cookie, sizeof(cookie)); 2428 2429 /* 2430 * Send our public key. We include in the packet 64 bits of random 2431 * data that must be matched in the reply in order to prevent IP 2432 * spoofing. 2433 */ 2434 packet_start(SSH_SMSG_PUBLIC_KEY); 2435 for (i = 0; i < 8; i++) 2436 packet_put_char(cookie[i]); 2437 2438 /* Store our public server RSA key. */ 2439 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); 2440 packet_put_bignum(sensitive_data.server_key->rsa->e); 2441 packet_put_bignum(sensitive_data.server_key->rsa->n); 2442 2443 /* Store our public host RSA key. */ 2444 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 2445 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); 2446 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); 2447 2448 /* Put protocol flags. */ 2449 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); 2450 2451 /* Declare which ciphers we support. */ 2452 packet_put_int(cipher_mask_ssh1(0)); 2453 2454 /* Declare supported authentication types. */ 2455 auth_mask = 0; 2456 if (options.rhosts_rsa_authentication) 2457 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; 2458 if (options.rsa_authentication) 2459 auth_mask |= 1 << SSH_AUTH_RSA; 2460 if (options.challenge_response_authentication == 1) 2461 auth_mask |= 1 << SSH_AUTH_TIS; 2462 if (options.password_authentication) 2463 auth_mask |= 1 << SSH_AUTH_PASSWORD; 2464 packet_put_int(auth_mask); 2465 2466 /* Send the packet and wait for it to be sent. */ 2467 packet_send(); 2468 packet_write_wait(); 2469 2470 debug("Sent %d bit server key and %d bit host key.", 2471 BN_num_bits(sensitive_data.server_key->rsa->n), 2472 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 2473 2474 /* Read clients reply (cipher type and session key). */ 2475 packet_read_expect(SSH_CMSG_SESSION_KEY); 2476 2477 /* Get cipher type and check whether we accept this. */ 2478 cipher_type = packet_get_char(); 2479 2480 if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) 2481 packet_disconnect("Warning: client selects unsupported cipher."); 2482 2483 /* Get check bytes from the packet. These must match those we 2484 sent earlier with the public key packet. */ 2485 for (i = 0; i < 8; i++) 2486 if (cookie[i] != packet_get_char()) 2487 packet_disconnect("IP Spoofing check bytes do not match."); 2488 2489 debug("Encryption type: %.200s", cipher_name(cipher_type)); 2490 2491 /* Get the encrypted integer. */ 2492 if ((real_key_int = BN_new()) == NULL) 2493 fatal("do_ssh1_kex: BN_new failed"); 2494 packet_get_bignum(real_key_int); 2495 2496 protocol_flags = packet_get_int(); 2497 packet_set_protocol_flags(protocol_flags); 2498 packet_check_eom(); 2499 2500 /* Setup a fake key in case RSA decryption fails */ 2501 if ((fake_key_int = BN_new()) == NULL) 2502 fatal("do_ssh1_kex: BN_new failed"); 2503 fake_key_len = BN_num_bytes(real_key_int); 2504 if (fake_key_len > sizeof(fake_key_bytes)) 2505 fake_key_len = sizeof(fake_key_bytes); 2506 arc4random_buf(fake_key_bytes, fake_key_len); 2507 if (BN_bin2bn(fake_key_bytes, fake_key_len, fake_key_int) == NULL) 2508 fatal("do_ssh1_kex: BN_bin2bn failed"); 2509 2510 /* Decrypt real_key_int using host/server keys */ 2511 rsafail = PRIVSEP(ssh1_session_key(real_key_int)); 2512 /* If decryption failed, use the fake key. Else, the real key. */ 2513 if (rsafail) 2514 session_key_int = fake_key_int; 2515 else 2516 session_key_int = real_key_int; 2517 2518 /* 2519 * Extract session key from the decrypted integer. The key is in the 2520 * least significant 256 bits of the integer; the first byte of the 2521 * key is in the highest bits. 2522 */ 2523 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); 2524 len = BN_num_bytes(session_key_int); 2525 if (len < 0 || (u_int)len > sizeof(session_key)) { 2526 error("%s: bad session key len from %s port %d: " 2527 "session_key_int %d > sizeof(session_key) %lu", __func__, 2528 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 2529 len, (u_long)sizeof(session_key)); 2530 rsafail++; 2531 } else { 2532 explicit_bzero(session_key, sizeof(session_key)); 2533 BN_bn2bin(session_key_int, 2534 session_key + sizeof(session_key) - len); 2535 2536 derive_ssh1_session_id( 2537 sensitive_data.ssh1_host_key->rsa->n, 2538 sensitive_data.server_key->rsa->n, 2539 cookie, session_id); 2540 /* 2541 * Xor the first 16 bytes of the session key with the 2542 * session id. 2543 */ 2544 for (i = 0; i < 16; i++) 2545 session_key[i] ^= session_id[i]; 2546 } 2547 2548 /* Destroy the private and public keys. No longer. */ 2549 destroy_sensitive_data(); 2550 2551 if (use_privsep) 2552 mm_ssh1_session_id(session_id); 2553 2554 /* Destroy the decrypted integer. It is no longer needed. */ 2555 BN_clear_free(real_key_int); 2556 BN_clear_free(fake_key_int); 2557 2558 /* Set the session key. From this on all communications will be encrypted. */ 2559 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); 2560 2561 /* Destroy our copy of the session key. It is no longer needed. */ 2562 explicit_bzero(session_key, sizeof(session_key)); 2563 2564 debug("Received session key; encryption turned on."); 2565 2566 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ 2567 packet_start(SSH_SMSG_SUCCESS); 2568 packet_send(); 2569 packet_write_wait(); 2570 } 2571 #endif 2572 2573 int 2574 sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen, 2575 const u_char *data, size_t dlen, const char *alg, u_int flag) 2576 { 2577 int r; 2578 u_int xxx_slen, xxx_dlen = dlen; 2579 2580 if (privkey) { 2581 if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen, 2582 alg) < 0)) 2583 fatal("%s: key_sign failed", __func__); 2584 if (slen) 2585 *slen = xxx_slen; 2586 } else if (use_privsep) { 2587 if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen, 2588 alg) < 0) 2589 fatal("%s: pubkey_sign failed", __func__); 2590 if (slen) 2591 *slen = xxx_slen; 2592 } else { 2593 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen, 2594 data, dlen, alg, datafellows)) != 0) 2595 fatal("%s: ssh_agent_sign failed: %s", 2596 __func__, ssh_err(r)); 2597 } 2598 return 0; 2599 } 2600 2601 /* SSH2 key exchange */ 2602 static void 2603 do_ssh2_kex(void) 2604 { 2605 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER }; 2606 struct kex *kex; 2607 int r; 2608 2609 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 2610 options.kex_algorithms); 2611 myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal( 2612 options.ciphers); 2613 myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal( 2614 options.ciphers); 2615 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 2616 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 2617 2618 if (options.compression == COMP_NONE) { 2619 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2620 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; 2621 } else if (options.compression == COMP_DELAYED) { 2622 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2623 myproposal[PROPOSAL_COMP_ALGS_STOC] = 2624 "none,zlib@openssh.com"; 2625 } 2626 2627 if (options.rekey_limit || options.rekey_interval) 2628 packet_set_rekey_limits(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_GRP14_SHA256] = kexdh_server; 2642 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server; 2643 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server; 2644 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 2645 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 2646 # ifdef OPENSSL_HAS_ECC 2647 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 2648 # endif 2649 #endif 2650 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 2651 kex->server = 1; 2652 kex->client_version_string=client_version_string; 2653 kex->server_version_string=server_version_string; 2654 kex->load_host_public_key=&get_hostkey_public_by_type; 2655 kex->load_host_private_key=&get_hostkey_private_by_type; 2656 kex->host_key_index=&get_hostkey_index; 2657 kex->sign = sshd_hostkey_sign; 2658 2659 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state); 2660 2661 session_id2 = kex->session_id; 2662 session_id2_len = kex->session_id_len; 2663 2664 #ifdef DEBUG_KEXDH 2665 /* send 1st encrypted/maced/compressed message */ 2666 packet_start(SSH2_MSG_IGNORE); 2667 packet_put_cstring("markus"); 2668 packet_send(); 2669 packet_write_wait(); 2670 #endif 2671 debug("KEX done"); 2672 } 2673 2674 /* server specific fatal cleanup */ 2675 void 2676 cleanup_exit(int i) 2677 { 2678 if (the_authctxt) { 2679 do_cleanup(the_authctxt); 2680 if (use_privsep && privsep_is_preauth && 2681 pmonitor != NULL && pmonitor->m_pid > 1) { 2682 debug("Killing privsep child %d", pmonitor->m_pid); 2683 if (kill(pmonitor->m_pid, SIGKILL) != 0 && 2684 errno != ESRCH) 2685 error("%s: kill(%d): %s", __func__, 2686 pmonitor->m_pid, strerror(errno)); 2687 } 2688 } 2689 #ifdef SSH_AUDIT_EVENTS 2690 /* done after do_cleanup so it can cancel the PAM auth 'thread' */ 2691 if (!use_privsep || mm_is_monitor()) 2692 audit_event(SSH_CONNECTION_ABANDON); 2693 #endif 2694 _exit(i); 2695 } 2696