1 /* $OpenBSD: sshd.c,v 1.366 2009/01/22 10:02:34 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 <sys/types.h> 46 #include <sys/ioctl.h> 47 #include <sys/wait.h> 48 #include <sys/tree.h> 49 #include <sys/stat.h> 50 #include <sys/socket.h> 51 #include <sys/time.h> 52 #include <sys/queue.h> 53 54 #include <errno.h> 55 #include <fcntl.h> 56 #include <netdb.h> 57 #include <paths.h> 58 #include <pwd.h> 59 #include <signal.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <unistd.h> 64 65 #include <openssl/dh.h> 66 #include <openssl/bn.h> 67 #include <openssl/md5.h> 68 #include <openssl/rand.h> 69 70 #include "xmalloc.h" 71 #include "ssh.h" 72 #include "ssh1.h" 73 #include "ssh2.h" 74 #include "rsa.h" 75 #include "sshpty.h" 76 #include "packet.h" 77 #include "log.h" 78 #include "buffer.h" 79 #include "servconf.h" 80 #include "uidswap.h" 81 #include "compat.h" 82 #include "cipher.h" 83 #include "key.h" 84 #include "kex.h" 85 #include "dh.h" 86 #include "myproposal.h" 87 #include "authfile.h" 88 #include "pathnames.h" 89 #include "atomicio.h" 90 #include "canohost.h" 91 #include "hostfile.h" 92 #include "auth.h" 93 #include "misc.h" 94 #include "msg.h" 95 #include "dispatch.h" 96 #include "channels.h" 97 #include "session.h" 98 #include "monitor_mm.h" 99 #include "monitor.h" 100 #ifdef GSSAPI 101 #include "ssh-gss.h" 102 #endif 103 #include "monitor_wrap.h" 104 #include "version.h" 105 106 #ifdef LIBWRAP 107 #include <tcpd.h> 108 #include <syslog.h> 109 int allow_severity = LOG_INFO; 110 int deny_severity = LOG_WARNING; 111 #endif /* LIBWRAP */ 112 113 #ifndef O_NOCTTY 114 #define O_NOCTTY 0 115 #endif 116 117 /* Re-exec fds */ 118 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) 119 #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) 120 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) 121 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) 122 123 extern char *__progname; 124 125 /* Server configuration options. */ 126 ServerOptions options; 127 128 /* Name of the server configuration file. */ 129 char *config_file_name = _PATH_SERVER_CONFIG_FILE; 130 131 /* 132 * Debug mode flag. This can be set on the command line. If debug 133 * mode is enabled, extra debugging output will be sent to the system 134 * log, the daemon will not go to background, and will exit after processing 135 * the first connection. 136 */ 137 int debug_flag = 0; 138 139 /* Flag indicating that the daemon should only test the configuration and keys. */ 140 int test_flag = 0; 141 142 /* Flag indicating that the daemon is being started from inetd. */ 143 int inetd_flag = 0; 144 145 /* Flag indicating that sshd should not detach and become a daemon. */ 146 int no_daemon_flag = 0; 147 148 /* debug goes to stderr unless inetd_flag is set */ 149 int log_stderr = 0; 150 151 /* Saved arguments to main(). */ 152 char **saved_argv; 153 154 /* re-exec */ 155 int rexeced_flag = 0; 156 int rexec_flag = 1; 157 int rexec_argc = 0; 158 char **rexec_argv; 159 160 /* 161 * The sockets that the server is listening; this is used in the SIGHUP 162 * signal handler. 163 */ 164 #define MAX_LISTEN_SOCKS 16 165 int listen_socks[MAX_LISTEN_SOCKS]; 166 int num_listen_socks = 0; 167 168 /* 169 * the client's version string, passed by sshd2 in compat mode. if != NULL, 170 * sshd will skip the version-number exchange 171 */ 172 char *client_version_string = NULL; 173 char *server_version_string = NULL; 174 175 /* for rekeying XXX fixme */ 176 Kex *xxx_kex; 177 178 /* 179 * Any really sensitive data in the application is contained in this 180 * structure. The idea is that this structure could be locked into memory so 181 * that the pages do not get written into swap. However, there are some 182 * problems. The private key contains BIGNUMs, and we do not (in principle) 183 * have access to the internals of them, and locking just the structure is 184 * not very useful. Currently, memory locking is not implemented. 185 */ 186 struct { 187 Key *server_key; /* ephemeral server key */ 188 Key *ssh1_host_key; /* ssh1 host key */ 189 Key **host_keys; /* all private host keys */ 190 int have_ssh1_key; 191 int have_ssh2_key; 192 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; 193 } sensitive_data; 194 195 /* 196 * Flag indicating whether the RSA server key needs to be regenerated. 197 * Is set in the SIGALRM handler and cleared when the key is regenerated. 198 */ 199 static volatile sig_atomic_t key_do_regen = 0; 200 201 /* This is set to true when a signal is received. */ 202 static volatile sig_atomic_t received_sighup = 0; 203 static volatile sig_atomic_t received_sigterm = 0; 204 205 /* session identifier, used by RSA-auth */ 206 u_char session_id[16]; 207 208 /* same for ssh2 */ 209 u_char *session_id2 = NULL; 210 u_int session_id2_len = 0; 211 212 /* record remote hostname or ip */ 213 u_int utmp_len = MAXHOSTNAMELEN; 214 215 /* options.max_startup sized array of fd ints */ 216 int *startup_pipes = NULL; 217 int startup_pipe; /* in child */ 218 219 /* variables used for privilege separation */ 220 int use_privsep = -1; 221 struct monitor *pmonitor = NULL; 222 223 /* global authentication context */ 224 Authctxt *the_authctxt = NULL; 225 226 /* sshd_config buffer */ 227 Buffer cfg; 228 229 /* message to be displayed after login */ 230 Buffer loginmsg; 231 232 /* Prototypes for various functions defined later in this file. */ 233 void destroy_sensitive_data(void); 234 void demote_sensitive_data(void); 235 236 static void do_ssh1_kex(void); 237 static void do_ssh2_kex(void); 238 239 /* 240 * Close all listening sockets 241 */ 242 static void 243 close_listen_socks(void) 244 { 245 int i; 246 247 for (i = 0; i < num_listen_socks; i++) 248 close(listen_socks[i]); 249 num_listen_socks = -1; 250 } 251 252 static void 253 close_startup_pipes(void) 254 { 255 int i; 256 257 if (startup_pipes) 258 for (i = 0; i < options.max_startups; i++) 259 if (startup_pipes[i] != -1) 260 close(startup_pipes[i]); 261 } 262 263 /* 264 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; 265 * the effect is to reread the configuration file (and to regenerate 266 * the server key). 267 */ 268 269 /*ARGSUSED*/ 270 static void 271 sighup_handler(int sig) 272 { 273 int save_errno = errno; 274 275 received_sighup = 1; 276 signal(SIGHUP, sighup_handler); 277 errno = save_errno; 278 } 279 280 /* 281 * Called from the main program after receiving SIGHUP. 282 * Restarts the server. 283 */ 284 static void 285 sighup_restart(void) 286 { 287 logit("Received SIGHUP; restarting."); 288 close_listen_socks(); 289 close_startup_pipes(); 290 alarm(0); /* alarm timer persists across exec */ 291 execv(saved_argv[0], saved_argv); 292 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], 293 strerror(errno)); 294 exit(1); 295 } 296 297 /* 298 * Generic signal handler for terminating signals in the master daemon. 299 */ 300 /*ARGSUSED*/ 301 static void 302 sigterm_handler(int sig) 303 { 304 received_sigterm = sig; 305 } 306 307 /* 308 * SIGCHLD handler. This is called whenever a child dies. This will then 309 * reap any zombies left by exited children. 310 */ 311 /*ARGSUSED*/ 312 static void 313 main_sigchld_handler(int sig) 314 { 315 int save_errno = errno; 316 pid_t pid; 317 int status; 318 319 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 320 (pid < 0 && errno == EINTR)) 321 ; 322 323 signal(SIGCHLD, main_sigchld_handler); 324 errno = save_errno; 325 } 326 327 /* 328 * Signal handler for the alarm after the login grace period has expired. 329 */ 330 /*ARGSUSED*/ 331 static void 332 grace_alarm_handler(int sig) 333 { 334 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) 335 kill(pmonitor->m_pid, SIGALRM); 336 337 /* Log error and exit. */ 338 sigdie("Timeout before authentication for %s", get_remote_ipaddr()); 339 } 340 341 /* 342 * Signal handler for the key regeneration alarm. Note that this 343 * alarm only occurs in the daemon waiting for connections, and it does not 344 * do anything with the private key or random state before forking. 345 * Thus there should be no concurrency control/asynchronous execution 346 * problems. 347 */ 348 static void 349 generate_ephemeral_server_key(void) 350 { 351 verbose("Generating %s%d bit RSA key.", 352 sensitive_data.server_key ? "new " : "", options.server_key_bits); 353 if (sensitive_data.server_key != NULL) 354 key_free(sensitive_data.server_key); 355 sensitive_data.server_key = key_generate(KEY_RSA1, 356 options.server_key_bits); 357 verbose("RSA key generation complete."); 358 359 arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); 360 arc4random_stir(); 361 } 362 363 /*ARGSUSED*/ 364 static void 365 key_regeneration_alarm(int sig) 366 { 367 int save_errno = errno; 368 369 signal(SIGALRM, SIG_DFL); 370 errno = save_errno; 371 key_do_regen = 1; 372 } 373 374 static void 375 sshd_exchange_identification(int sock_in, int sock_out) 376 { 377 u_int i; 378 int mismatch; 379 int remote_major, remote_minor; 380 int major, minor; 381 char *s, *newline = "\n"; 382 char buf[256]; /* Must not be larger than remote_version. */ 383 char remote_version[256]; /* Must be at least as big as buf. */ 384 385 if ((options.protocol & SSH_PROTO_1) && 386 (options.protocol & SSH_PROTO_2)) { 387 major = PROTOCOL_MAJOR_1; 388 minor = 99; 389 } else if (options.protocol & SSH_PROTO_2) { 390 major = PROTOCOL_MAJOR_2; 391 minor = PROTOCOL_MINOR_2; 392 newline = "\r\n"; 393 } else { 394 major = PROTOCOL_MAJOR_1; 395 minor = PROTOCOL_MINOR_1; 396 } 397 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", major, minor, 398 SSH_VERSION, newline); 399 server_version_string = xstrdup(buf); 400 401 /* Send our protocol version identification. */ 402 if (atomicio(vwrite, sock_out, server_version_string, 403 strlen(server_version_string)) 404 != strlen(server_version_string)) { 405 logit("Could not write ident string to %s", get_remote_ipaddr()); 406 cleanup_exit(255); 407 } 408 409 /* Read other sides version identification. */ 410 memset(buf, 0, sizeof(buf)); 411 for (i = 0; i < sizeof(buf) - 1; i++) { 412 if (atomicio(read, sock_in, &buf[i], 1) != 1) { 413 logit("Did not receive identification string from %s", 414 get_remote_ipaddr()); 415 cleanup_exit(255); 416 } 417 if (buf[i] == '\r') { 418 buf[i] = 0; 419 /* Kludge for F-Secure Macintosh < 1.0.2 */ 420 if (i == 12 && 421 strncmp(buf, "SSH-1.5-W1.0", 12) == 0) 422 break; 423 continue; 424 } 425 if (buf[i] == '\n') { 426 buf[i] = 0; 427 break; 428 } 429 } 430 buf[sizeof(buf) - 1] = 0; 431 client_version_string = xstrdup(buf); 432 433 /* 434 * Check that the versions match. In future this might accept 435 * several versions and set appropriate flags to handle them. 436 */ 437 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", 438 &remote_major, &remote_minor, remote_version) != 3) { 439 s = "Protocol mismatch.\n"; 440 (void) atomicio(vwrite, sock_out, s, strlen(s)); 441 close(sock_in); 442 close(sock_out); 443 logit("Bad protocol version identification '%.100s' from %s", 444 client_version_string, get_remote_ipaddr()); 445 cleanup_exit(255); 446 } 447 debug("Client protocol version %d.%d; client software version %.100s", 448 remote_major, remote_minor, remote_version); 449 450 compat_datafellows(remote_version); 451 452 if (datafellows & SSH_BUG_PROBE) { 453 logit("probed from %s with %s. Don't panic.", 454 get_remote_ipaddr(), client_version_string); 455 cleanup_exit(255); 456 } 457 458 if (datafellows & SSH_BUG_SCANNER) { 459 logit("scanned from %s with %s. Don't panic.", 460 get_remote_ipaddr(), client_version_string); 461 cleanup_exit(255); 462 } 463 464 mismatch = 0; 465 switch (remote_major) { 466 case 1: 467 if (remote_minor == 99) { 468 if (options.protocol & SSH_PROTO_2) 469 enable_compat20(); 470 else 471 mismatch = 1; 472 break; 473 } 474 if (!(options.protocol & SSH_PROTO_1)) { 475 mismatch = 1; 476 break; 477 } 478 if (remote_minor < 3) { 479 packet_disconnect("Your ssh version is too old and " 480 "is no longer supported. Please install a newer version."); 481 } else if (remote_minor == 3) { 482 /* note that this disables agent-forwarding */ 483 enable_compat13(); 484 } 485 break; 486 case 2: 487 if (options.protocol & SSH_PROTO_2) { 488 enable_compat20(); 489 break; 490 } 491 /* FALLTHROUGH */ 492 default: 493 mismatch = 1; 494 break; 495 } 496 chop(server_version_string); 497 debug("Local version string %.200s", server_version_string); 498 499 if (mismatch) { 500 s = "Protocol major versions differ.\n"; 501 (void) atomicio(vwrite, sock_out, s, strlen(s)); 502 close(sock_in); 503 close(sock_out); 504 logit("Protocol major versions differ for %s: %.200s vs. %.200s", 505 get_remote_ipaddr(), 506 server_version_string, client_version_string); 507 cleanup_exit(255); 508 } 509 } 510 511 /* Destroy the host and server keys. They will no longer be needed. */ 512 void 513 destroy_sensitive_data(void) 514 { 515 int i; 516 517 if (sensitive_data.server_key) { 518 key_free(sensitive_data.server_key); 519 sensitive_data.server_key = NULL; 520 } 521 for (i = 0; i < options.num_host_key_files; i++) { 522 if (sensitive_data.host_keys[i]) { 523 key_free(sensitive_data.host_keys[i]); 524 sensitive_data.host_keys[i] = NULL; 525 } 526 } 527 sensitive_data.ssh1_host_key = NULL; 528 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); 529 } 530 531 /* Demote private to public keys for network child */ 532 void 533 demote_sensitive_data(void) 534 { 535 Key *tmp; 536 int i; 537 538 if (sensitive_data.server_key) { 539 tmp = key_demote(sensitive_data.server_key); 540 key_free(sensitive_data.server_key); 541 sensitive_data.server_key = tmp; 542 } 543 544 for (i = 0; i < options.num_host_key_files; i++) { 545 if (sensitive_data.host_keys[i]) { 546 tmp = key_demote(sensitive_data.host_keys[i]); 547 key_free(sensitive_data.host_keys[i]); 548 sensitive_data.host_keys[i] = tmp; 549 if (tmp->type == KEY_RSA1) 550 sensitive_data.ssh1_host_key = tmp; 551 } 552 } 553 554 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ 555 } 556 557 static void 558 privsep_preauth_child(void) 559 { 560 u_int32_t rnd[256]; 561 gid_t gidset[1]; 562 struct passwd *pw; 563 564 /* Enable challenge-response authentication for privilege separation */ 565 privsep_challenge_enable(); 566 567 arc4random_stir(); 568 arc4random_buf(rnd, sizeof(rnd)); 569 RAND_seed(rnd, sizeof(rnd)); 570 571 /* Demote the private keys to public keys. */ 572 demote_sensitive_data(); 573 574 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) 575 fatal("Privilege separation user %s does not exist", 576 SSH_PRIVSEP_USER); 577 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); 578 endpwent(); 579 580 /* Change our root directory */ 581 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) 582 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, 583 strerror(errno)); 584 if (chdir("/") == -1) 585 fatal("chdir(\"/\"): %s", strerror(errno)); 586 587 /* Drop our privileges */ 588 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, 589 (u_int)pw->pw_gid); 590 #if 0 591 /* XXX not ready, too heavy after chroot */ 592 do_setusercontext(pw); 593 #else 594 gidset[0] = pw->pw_gid; 595 if (setgroups(1, gidset) < 0) 596 fatal("setgroups: %.100s", strerror(errno)); 597 permanently_set_uid(pw); 598 #endif 599 } 600 601 static int 602 privsep_preauth(Authctxt *authctxt) 603 { 604 int status; 605 pid_t pid; 606 607 /* Set up unprivileged child process to deal with network data */ 608 pmonitor = monitor_init(); 609 /* Store a pointer to the kex for later rekeying */ 610 pmonitor->m_pkex = &xxx_kex; 611 612 pid = fork(); 613 if (pid == -1) { 614 fatal("fork of unprivileged child failed"); 615 } else if (pid != 0) { 616 debug2("Network child is on pid %ld", (long)pid); 617 618 close(pmonitor->m_recvfd); 619 pmonitor->m_pid = pid; 620 monitor_child_preauth(authctxt, pmonitor); 621 close(pmonitor->m_sendfd); 622 623 /* Sync memory */ 624 monitor_sync(pmonitor); 625 626 /* Wait for the child's exit status */ 627 while (waitpid(pid, &status, 0) < 0) 628 if (errno != EINTR) 629 break; 630 return (1); 631 } else { 632 /* child */ 633 634 close(pmonitor->m_sendfd); 635 636 /* Demote the child */ 637 if (getuid() == 0 || geteuid() == 0) 638 privsep_preauth_child(); 639 setproctitle("%s", "[net]"); 640 } 641 return (0); 642 } 643 644 static void 645 privsep_postauth(Authctxt *authctxt) 646 { 647 u_int32_t rnd[256]; 648 649 if (authctxt->pw->pw_uid == 0 || options.use_login) { 650 /* File descriptor passing is broken or root login */ 651 use_privsep = 0; 652 goto skip; 653 } 654 655 /* New socket pair */ 656 monitor_reinit(pmonitor); 657 658 pmonitor->m_pid = fork(); 659 if (pmonitor->m_pid == -1) 660 fatal("fork of unprivileged child failed"); 661 else if (pmonitor->m_pid != 0) { 662 verbose("User child is on pid %ld", (long)pmonitor->m_pid); 663 close(pmonitor->m_recvfd); 664 buffer_clear(&loginmsg); 665 monitor_child_postauth(pmonitor); 666 667 /* NEVERREACHED */ 668 exit(0); 669 } 670 671 close(pmonitor->m_sendfd); 672 673 /* Demote the private keys to public keys. */ 674 demote_sensitive_data(); 675 676 arc4random_stir(); 677 arc4random_buf(rnd, sizeof(rnd)); 678 RAND_seed(rnd, sizeof(rnd)); 679 680 /* Drop privileges */ 681 do_setusercontext(authctxt->pw); 682 683 skip: 684 /* It is safe now to apply the key state */ 685 monitor_apply_keystate(pmonitor); 686 687 /* 688 * Tell the packet layer that authentication was successful, since 689 * this information is not part of the key state. 690 */ 691 packet_set_authenticated(); 692 } 693 694 static char * 695 list_hostkey_types(void) 696 { 697 Buffer b; 698 const char *p; 699 char *ret; 700 int i; 701 702 buffer_init(&b); 703 for (i = 0; i < options.num_host_key_files; i++) { 704 Key *key = sensitive_data.host_keys[i]; 705 if (key == NULL) 706 continue; 707 switch (key->type) { 708 case KEY_RSA: 709 case KEY_DSA: 710 if (buffer_len(&b) > 0) 711 buffer_append(&b, ",", 1); 712 p = key_ssh_name(key); 713 buffer_append(&b, p, strlen(p)); 714 break; 715 } 716 } 717 buffer_append(&b, "\0", 1); 718 ret = xstrdup(buffer_ptr(&b)); 719 buffer_free(&b); 720 debug("list_hostkey_types: %s", ret); 721 return ret; 722 } 723 724 Key * 725 get_hostkey_by_type(int type) 726 { 727 int i; 728 729 for (i = 0; i < options.num_host_key_files; i++) { 730 Key *key = sensitive_data.host_keys[i]; 731 if (key != NULL && key->type == type) 732 return key; 733 } 734 return NULL; 735 } 736 737 Key * 738 get_hostkey_by_index(int ind) 739 { 740 if (ind < 0 || ind >= options.num_host_key_files) 741 return (NULL); 742 return (sensitive_data.host_keys[ind]); 743 } 744 745 int 746 get_hostkey_index(Key *key) 747 { 748 int i; 749 750 for (i = 0; i < options.num_host_key_files; i++) { 751 if (key == sensitive_data.host_keys[i]) 752 return (i); 753 } 754 return (-1); 755 } 756 757 /* 758 * returns 1 if connection should be dropped, 0 otherwise. 759 * dropping starts at connection #max_startups_begin with a probability 760 * of (max_startups_rate/100). the probability increases linearly until 761 * all connections are dropped for startups > max_startups 762 */ 763 static int 764 drop_connection(int startups) 765 { 766 int p, r; 767 768 if (startups < options.max_startups_begin) 769 return 0; 770 if (startups >= options.max_startups) 771 return 1; 772 if (options.max_startups_rate == 100) 773 return 1; 774 775 p = 100 - options.max_startups_rate; 776 p *= startups - options.max_startups_begin; 777 p /= options.max_startups - options.max_startups_begin; 778 p += options.max_startups_rate; 779 r = arc4random_uniform(100); 780 781 debug("drop_connection: p %d, r %d", p, r); 782 return (r < p) ? 1 : 0; 783 } 784 785 static void 786 usage(void) 787 { 788 fprintf(stderr, "%s, %s\n", 789 SSH_VERSION, SSLeay_version(SSLEAY_VERSION)); 790 fprintf(stderr, 791 "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-f config_file]\n" 792 " [-g login_grace_time] [-h host_key_file] [-k key_gen_time]\n" 793 " [-o option] [-p port] [-u len]\n" 794 ); 795 exit(1); 796 } 797 798 static void 799 send_rexec_state(int fd, Buffer *conf) 800 { 801 Buffer m; 802 803 debug3("%s: entering fd = %d config len %d", __func__, fd, 804 buffer_len(conf)); 805 806 /* 807 * Protocol from reexec master to child: 808 * string configuration 809 * u_int ephemeral_key_follows 810 * bignum e (only if ephemeral_key_follows == 1) 811 * bignum n " 812 * bignum d " 813 * bignum iqmp " 814 * bignum p " 815 * bignum q " 816 */ 817 buffer_init(&m); 818 buffer_put_cstring(&m, buffer_ptr(conf)); 819 820 if (sensitive_data.server_key != NULL && 821 sensitive_data.server_key->type == KEY_RSA1) { 822 buffer_put_int(&m, 1); 823 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); 824 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); 825 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); 826 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); 827 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); 828 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); 829 } else 830 buffer_put_int(&m, 0); 831 832 if (ssh_msg_send(fd, 0, &m) == -1) 833 fatal("%s: ssh_msg_send failed", __func__); 834 835 buffer_free(&m); 836 837 debug3("%s: done", __func__); 838 } 839 840 static void 841 recv_rexec_state(int fd, Buffer *conf) 842 { 843 Buffer m; 844 char *cp; 845 u_int len; 846 847 debug3("%s: entering fd = %d", __func__, fd); 848 849 buffer_init(&m); 850 851 if (ssh_msg_recv(fd, &m) == -1) 852 fatal("%s: ssh_msg_recv failed", __func__); 853 if (buffer_get_char(&m) != 0) 854 fatal("%s: rexec version mismatch", __func__); 855 856 cp = buffer_get_string(&m, &len); 857 if (conf != NULL) 858 buffer_append(conf, cp, len + 1); 859 xfree(cp); 860 861 if (buffer_get_int(&m)) { 862 if (sensitive_data.server_key != NULL) 863 key_free(sensitive_data.server_key); 864 sensitive_data.server_key = key_new_private(KEY_RSA1); 865 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); 866 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); 867 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); 868 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); 869 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); 870 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); 871 rsa_generate_additional_parameters( 872 sensitive_data.server_key->rsa); 873 } 874 buffer_free(&m); 875 876 debug3("%s: done", __func__); 877 } 878 879 /* Accept a connection from inetd */ 880 static void 881 server_accept_inetd(int *sock_in, int *sock_out) 882 { 883 int fd; 884 885 startup_pipe = -1; 886 if (rexeced_flag) { 887 close(REEXEC_CONFIG_PASS_FD); 888 *sock_in = *sock_out = dup(STDIN_FILENO); 889 if (!debug_flag) { 890 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); 891 close(REEXEC_STARTUP_PIPE_FD); 892 } 893 } else { 894 *sock_in = dup(STDIN_FILENO); 895 *sock_out = dup(STDOUT_FILENO); 896 } 897 /* 898 * We intentionally do not close the descriptors 0, 1, and 2 899 * as our code for setting the descriptors won't work if 900 * ttyfd happens to be one of those. 901 */ 902 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 903 dup2(fd, STDIN_FILENO); 904 dup2(fd, STDOUT_FILENO); 905 if (fd > STDOUT_FILENO) 906 close(fd); 907 } 908 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); 909 } 910 911 /* 912 * Listen for TCP connections 913 */ 914 static void 915 server_listen(void) 916 { 917 int ret, listen_sock, on = 1; 918 struct addrinfo *ai; 919 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 920 921 for (ai = options.listen_addrs; ai; ai = ai->ai_next) { 922 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 923 continue; 924 if (num_listen_socks >= MAX_LISTEN_SOCKS) 925 fatal("Too many listen sockets. " 926 "Enlarge MAX_LISTEN_SOCKS"); 927 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, 928 ntop, sizeof(ntop), strport, sizeof(strport), 929 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { 930 error("getnameinfo failed: %.100s", 931 ssh_gai_strerror(ret)); 932 continue; 933 } 934 /* Create socket for listening. */ 935 listen_sock = socket(ai->ai_family, ai->ai_socktype, 936 ai->ai_protocol); 937 if (listen_sock < 0) { 938 /* kernel may not support ipv6 */ 939 verbose("socket: %.100s", strerror(errno)); 940 continue; 941 } 942 if (set_nonblock(listen_sock) == -1) { 943 close(listen_sock); 944 continue; 945 } 946 /* 947 * Set socket options. 948 * Allow local port reuse in TIME_WAIT. 949 */ 950 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, 951 &on, sizeof(on)) == -1) 952 error("setsockopt SO_REUSEADDR: %s", strerror(errno)); 953 954 debug("Bind to port %s on %s.", strport, ntop); 955 956 /* Bind the socket to the desired port. */ 957 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { 958 error("Bind to port %s on %s failed: %.200s.", 959 strport, ntop, strerror(errno)); 960 close(listen_sock); 961 continue; 962 } 963 listen_socks[num_listen_socks] = listen_sock; 964 num_listen_socks++; 965 966 /* Start listening on the port. */ 967 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) 968 fatal("listen on [%s]:%s: %.100s", 969 ntop, strport, strerror(errno)); 970 logit("Server listening on %s port %s.", ntop, strport); 971 } 972 freeaddrinfo(options.listen_addrs); 973 974 if (!num_listen_socks) 975 fatal("Cannot bind any address."); 976 } 977 978 /* 979 * The main TCP accept loop. Note that, for the non-debug case, returns 980 * from this function are in a forked subprocess. 981 */ 982 static void 983 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) 984 { 985 fd_set *fdset; 986 int i, j, ret, maxfd; 987 int key_used = 0, startups = 0; 988 int startup_p[2] = { -1 , -1 }; 989 struct sockaddr_storage from; 990 socklen_t fromlen; 991 pid_t pid; 992 993 /* setup fd set for accept */ 994 fdset = NULL; 995 maxfd = 0; 996 for (i = 0; i < num_listen_socks; i++) 997 if (listen_socks[i] > maxfd) 998 maxfd = listen_socks[i]; 999 /* pipes connected to unauthenticated childs */ 1000 startup_pipes = xcalloc(options.max_startups, sizeof(int)); 1001 for (i = 0; i < options.max_startups; i++) 1002 startup_pipes[i] = -1; 1003 1004 /* 1005 * Stay listening for connections until the system crashes or 1006 * the daemon is killed with a signal. 1007 */ 1008 for (;;) { 1009 if (received_sighup) 1010 sighup_restart(); 1011 if (fdset != NULL) 1012 xfree(fdset); 1013 fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), 1014 sizeof(fd_mask)); 1015 1016 for (i = 0; i < num_listen_socks; i++) 1017 FD_SET(listen_socks[i], fdset); 1018 for (i = 0; i < options.max_startups; i++) 1019 if (startup_pipes[i] != -1) 1020 FD_SET(startup_pipes[i], fdset); 1021 1022 /* Wait in select until there is a connection. */ 1023 ret = select(maxfd+1, fdset, NULL, NULL, NULL); 1024 if (ret < 0 && errno != EINTR) 1025 error("select: %.100s", strerror(errno)); 1026 if (received_sigterm) { 1027 logit("Received signal %d; terminating.", 1028 (int) received_sigterm); 1029 close_listen_socks(); 1030 unlink(options.pid_file); 1031 exit(255); 1032 } 1033 if (key_used && key_do_regen) { 1034 generate_ephemeral_server_key(); 1035 key_used = 0; 1036 key_do_regen = 0; 1037 } 1038 if (ret < 0) 1039 continue; 1040 1041 for (i = 0; i < options.max_startups; i++) 1042 if (startup_pipes[i] != -1 && 1043 FD_ISSET(startup_pipes[i], fdset)) { 1044 /* 1045 * the read end of the pipe is ready 1046 * if the child has closed the pipe 1047 * after successful authentication 1048 * or if the child has died 1049 */ 1050 close(startup_pipes[i]); 1051 startup_pipes[i] = -1; 1052 startups--; 1053 } 1054 for (i = 0; i < num_listen_socks; i++) { 1055 if (!FD_ISSET(listen_socks[i], fdset)) 1056 continue; 1057 fromlen = sizeof(from); 1058 *newsock = accept(listen_socks[i], 1059 (struct sockaddr *)&from, &fromlen); 1060 if (*newsock < 0) { 1061 if (errno != EINTR && errno != EWOULDBLOCK) 1062 error("accept: %.100s", strerror(errno)); 1063 continue; 1064 } 1065 if (unset_nonblock(*newsock) == -1) { 1066 close(*newsock); 1067 continue; 1068 } 1069 if (drop_connection(startups) == 1) { 1070 debug("drop connection #%d", startups); 1071 close(*newsock); 1072 continue; 1073 } 1074 if (pipe(startup_p) == -1) { 1075 close(*newsock); 1076 continue; 1077 } 1078 1079 if (rexec_flag && socketpair(AF_UNIX, 1080 SOCK_STREAM, 0, config_s) == -1) { 1081 error("reexec socketpair: %s", 1082 strerror(errno)); 1083 close(*newsock); 1084 close(startup_p[0]); 1085 close(startup_p[1]); 1086 continue; 1087 } 1088 1089 for (j = 0; j < options.max_startups; j++) 1090 if (startup_pipes[j] == -1) { 1091 startup_pipes[j] = startup_p[0]; 1092 if (maxfd < startup_p[0]) 1093 maxfd = startup_p[0]; 1094 startups++; 1095 break; 1096 } 1097 1098 /* 1099 * Got connection. Fork a child to handle it, unless 1100 * we are in debugging mode. 1101 */ 1102 if (debug_flag) { 1103 /* 1104 * In debugging mode. Close the listening 1105 * socket, and start processing the 1106 * connection without forking. 1107 */ 1108 debug("Server will not fork when running in debugging mode."); 1109 close_listen_socks(); 1110 *sock_in = *newsock; 1111 *sock_out = *newsock; 1112 close(startup_p[0]); 1113 close(startup_p[1]); 1114 startup_pipe = -1; 1115 pid = getpid(); 1116 if (rexec_flag) { 1117 send_rexec_state(config_s[0], 1118 &cfg); 1119 close(config_s[0]); 1120 } 1121 break; 1122 } 1123 1124 /* 1125 * Normal production daemon. Fork, and have 1126 * the child process the connection. The 1127 * parent continues listening. 1128 */ 1129 if ((pid = fork()) == 0) { 1130 /* 1131 * Child. Close the listening and 1132 * max_startup sockets. Start using 1133 * the accepted socket. Reinitialize 1134 * logging (since our pid has changed). 1135 * We break out of the loop to handle 1136 * the connection. 1137 */ 1138 startup_pipe = startup_p[1]; 1139 close_startup_pipes(); 1140 close_listen_socks(); 1141 *sock_in = *newsock; 1142 *sock_out = *newsock; 1143 log_init(__progname, 1144 options.log_level, 1145 options.log_facility, 1146 log_stderr); 1147 if (rexec_flag) 1148 close(config_s[0]); 1149 break; 1150 } 1151 1152 /* Parent. Stay in the loop. */ 1153 if (pid < 0) 1154 error("fork: %.100s", strerror(errno)); 1155 else 1156 debug("Forked child %ld.", (long)pid); 1157 1158 close(startup_p[1]); 1159 1160 if (rexec_flag) { 1161 send_rexec_state(config_s[0], &cfg); 1162 close(config_s[0]); 1163 close(config_s[1]); 1164 } 1165 1166 /* 1167 * Mark that the key has been used (it 1168 * was "given" to the child). 1169 */ 1170 if ((options.protocol & SSH_PROTO_1) && 1171 key_used == 0) { 1172 /* Schedule server key regeneration alarm. */ 1173 signal(SIGALRM, key_regeneration_alarm); 1174 alarm(options.key_regeneration_time); 1175 key_used = 1; 1176 } 1177 1178 close(*newsock); 1179 1180 /* 1181 * Ensure that our random state differs 1182 * from that of the child 1183 */ 1184 arc4random_stir(); 1185 } 1186 1187 /* child process check (or debug mode) */ 1188 if (num_listen_socks < 0) 1189 break; 1190 } 1191 } 1192 1193 1194 /* 1195 * Main program for the daemon. 1196 */ 1197 int 1198 main(int ac, char **av) 1199 { 1200 extern char *optarg; 1201 extern int optind; 1202 int opt, i, on = 1; 1203 int sock_in = -1, sock_out = -1, newsock = -1; 1204 const char *remote_ip; 1205 char *test_user = NULL, *test_host = NULL, *test_addr = NULL; 1206 int remote_port; 1207 char *line, *p, *cp; 1208 int config_s[2] = { -1 , -1 }; 1209 u_int64_t ibytes, obytes; 1210 mode_t new_umask; 1211 Key *key; 1212 Authctxt *authctxt; 1213 1214 /* Save argv. */ 1215 saved_argv = av; 1216 rexec_argc = ac; 1217 1218 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1219 sanitise_stdfd(); 1220 1221 /* Initialize configuration options to their default values. */ 1222 initialize_server_options(&options); 1223 1224 /* Parse command-line arguments. */ 1225 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:C:dDeiqrtQRT46")) != -1) { 1226 switch (opt) { 1227 case '4': 1228 options.address_family = AF_INET; 1229 break; 1230 case '6': 1231 options.address_family = AF_INET6; 1232 break; 1233 case 'f': 1234 config_file_name = optarg; 1235 break; 1236 case 'd': 1237 if (debug_flag == 0) { 1238 debug_flag = 1; 1239 options.log_level = SYSLOG_LEVEL_DEBUG1; 1240 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) 1241 options.log_level++; 1242 break; 1243 case 'D': 1244 no_daemon_flag = 1; 1245 break; 1246 case 'e': 1247 log_stderr = 1; 1248 break; 1249 case 'i': 1250 inetd_flag = 1; 1251 break; 1252 case 'r': 1253 rexec_flag = 0; 1254 break; 1255 case 'R': 1256 rexeced_flag = 1; 1257 inetd_flag = 1; 1258 break; 1259 case 'Q': 1260 /* ignored */ 1261 break; 1262 case 'q': 1263 options.log_level = SYSLOG_LEVEL_QUIET; 1264 break; 1265 case 'b': 1266 options.server_key_bits = (int)strtonum(optarg, 256, 1267 32768, NULL); 1268 break; 1269 case 'p': 1270 options.ports_from_cmdline = 1; 1271 if (options.num_ports >= MAX_PORTS) { 1272 fprintf(stderr, "too many ports.\n"); 1273 exit(1); 1274 } 1275 options.ports[options.num_ports++] = a2port(optarg); 1276 if (options.ports[options.num_ports-1] <= 0) { 1277 fprintf(stderr, "Bad port number.\n"); 1278 exit(1); 1279 } 1280 break; 1281 case 'g': 1282 if ((options.login_grace_time = convtime(optarg)) == -1) { 1283 fprintf(stderr, "Invalid login grace time.\n"); 1284 exit(1); 1285 } 1286 break; 1287 case 'k': 1288 if ((options.key_regeneration_time = convtime(optarg)) == -1) { 1289 fprintf(stderr, "Invalid key regeneration interval.\n"); 1290 exit(1); 1291 } 1292 break; 1293 case 'h': 1294 if (options.num_host_key_files >= MAX_HOSTKEYS) { 1295 fprintf(stderr, "too many host keys.\n"); 1296 exit(1); 1297 } 1298 options.host_key_files[options.num_host_key_files++] = optarg; 1299 break; 1300 case 't': 1301 test_flag = 1; 1302 break; 1303 case 'T': 1304 test_flag = 2; 1305 break; 1306 case 'C': 1307 cp = optarg; 1308 while ((p = strsep(&cp, ",")) && *p != '\0') { 1309 if (strncmp(p, "addr=", 5) == 0) 1310 test_addr = xstrdup(p + 5); 1311 else if (strncmp(p, "host=", 5) == 0) 1312 test_host = xstrdup(p + 5); 1313 else if (strncmp(p, "user=", 5) == 0) 1314 test_user = xstrdup(p + 5); 1315 else { 1316 fprintf(stderr, "Invalid test " 1317 "mode specification %s\n", p); 1318 exit(1); 1319 } 1320 } 1321 break; 1322 case 'u': 1323 utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); 1324 if (utmp_len > MAXHOSTNAMELEN) { 1325 fprintf(stderr, "Invalid utmp length.\n"); 1326 exit(1); 1327 } 1328 break; 1329 case 'o': 1330 line = xstrdup(optarg); 1331 if (process_server_config_line(&options, line, 1332 "command-line", 0, NULL, NULL, NULL, NULL) != 0) 1333 exit(1); 1334 xfree(line); 1335 break; 1336 case '?': 1337 default: 1338 usage(); 1339 break; 1340 } 1341 } 1342 if (rexeced_flag || inetd_flag) 1343 rexec_flag = 0; 1344 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) 1345 fatal("sshd re-exec requires execution with an absolute path"); 1346 if (rexeced_flag) 1347 closefrom(REEXEC_MIN_FREE_FD); 1348 else 1349 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); 1350 1351 SSLeay_add_all_algorithms(); 1352 1353 /* 1354 * Force logging to stderr until we have loaded the private host 1355 * key (unless started from inetd) 1356 */ 1357 log_init(__progname, 1358 options.log_level == SYSLOG_LEVEL_NOT_SET ? 1359 SYSLOG_LEVEL_INFO : options.log_level, 1360 options.log_facility == SYSLOG_FACILITY_NOT_SET ? 1361 SYSLOG_FACILITY_AUTH : options.log_facility, 1362 log_stderr || !inetd_flag); 1363 1364 sensitive_data.server_key = NULL; 1365 sensitive_data.ssh1_host_key = NULL; 1366 sensitive_data.have_ssh1_key = 0; 1367 sensitive_data.have_ssh2_key = 0; 1368 1369 /* 1370 * If we're doing an extended config test, make sure we have all of 1371 * the parameters we need. If we're not doing an extended test, 1372 * do not silently ignore connection test params. 1373 */ 1374 if (test_flag >= 2 && 1375 (test_user != NULL || test_host != NULL || test_addr != NULL) 1376 && (test_user == NULL || test_host == NULL || test_addr == NULL)) 1377 fatal("user, host and addr are all required when testing " 1378 "Match configs"); 1379 if (test_flag < 2 && (test_user != NULL || test_host != NULL || 1380 test_addr != NULL)) 1381 fatal("Config test connection parameter (-C) provided without " 1382 "test mode (-T)"); 1383 1384 /* Fetch our configuration */ 1385 buffer_init(&cfg); 1386 if (rexeced_flag) 1387 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); 1388 else 1389 load_server_config(config_file_name, &cfg); 1390 1391 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, 1392 &cfg, NULL, NULL, NULL); 1393 1394 /* Fill in default values for those options not explicitly set. */ 1395 fill_default_server_options(&options); 1396 1397 /* challenge-response is implemented via keyboard interactive */ 1398 if (options.challenge_response_authentication) 1399 options.kbd_interactive_authentication = 1; 1400 1401 /* set default channel AF */ 1402 channel_set_af(options.address_family); 1403 1404 /* Check that there are no remaining arguments. */ 1405 if (optind < ac) { 1406 fprintf(stderr, "Extra argument %s.\n", av[optind]); 1407 exit(1); 1408 } 1409 1410 debug("sshd version %.100s", SSH_VERSION); 1411 1412 /* load private host keys */ 1413 sensitive_data.host_keys = xcalloc(options.num_host_key_files, 1414 sizeof(Key *)); 1415 for (i = 0; i < options.num_host_key_files; i++) 1416 sensitive_data.host_keys[i] = NULL; 1417 1418 for (i = 0; i < options.num_host_key_files; i++) { 1419 key = key_load_private(options.host_key_files[i], "", NULL); 1420 sensitive_data.host_keys[i] = key; 1421 if (key == NULL) { 1422 error("Could not load host key: %s", 1423 options.host_key_files[i]); 1424 sensitive_data.host_keys[i] = NULL; 1425 continue; 1426 } 1427 switch (key->type) { 1428 case KEY_RSA1: 1429 sensitive_data.ssh1_host_key = key; 1430 sensitive_data.have_ssh1_key = 1; 1431 break; 1432 case KEY_RSA: 1433 case KEY_DSA: 1434 sensitive_data.have_ssh2_key = 1; 1435 break; 1436 } 1437 debug("private host key: #%d type %d %s", i, key->type, 1438 key_type(key)); 1439 } 1440 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { 1441 logit("Disabling protocol version 1. Could not load host key"); 1442 options.protocol &= ~SSH_PROTO_1; 1443 } 1444 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { 1445 logit("Disabling protocol version 2. Could not load host key"); 1446 options.protocol &= ~SSH_PROTO_2; 1447 } 1448 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { 1449 logit("sshd: no hostkeys available -- exiting."); 1450 exit(1); 1451 } 1452 1453 /* Check certain values for sanity. */ 1454 if (options.protocol & SSH_PROTO_1) { 1455 if (options.server_key_bits < 512 || 1456 options.server_key_bits > 32768) { 1457 fprintf(stderr, "Bad server key size.\n"); 1458 exit(1); 1459 } 1460 /* 1461 * Check that server and host key lengths differ sufficiently. This 1462 * is necessary to make double encryption work with rsaref. Oh, I 1463 * hate software patents. I dont know if this can go? Niels 1464 */ 1465 if (options.server_key_bits > 1466 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - 1467 SSH_KEY_BITS_RESERVED && options.server_key_bits < 1468 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1469 SSH_KEY_BITS_RESERVED) { 1470 options.server_key_bits = 1471 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1472 SSH_KEY_BITS_RESERVED; 1473 debug("Forcing server key to %d bits to make it differ from host key.", 1474 options.server_key_bits); 1475 } 1476 } 1477 1478 if (use_privsep) { 1479 struct stat st; 1480 1481 if (getpwnam(SSH_PRIVSEP_USER) == NULL) 1482 fatal("Privilege separation user %s does not exist", 1483 SSH_PRIVSEP_USER); 1484 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || 1485 (S_ISDIR(st.st_mode) == 0)) 1486 fatal("Missing privilege separation directory: %s", 1487 _PATH_PRIVSEP_CHROOT_DIR); 1488 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) 1489 fatal("%s must be owned by root and not group or " 1490 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); 1491 } 1492 1493 if (test_flag > 1) { 1494 if (test_user != NULL && test_addr != NULL && test_host != NULL) 1495 parse_server_match_config(&options, test_user, 1496 test_host, test_addr); 1497 dump_config(&options); 1498 } 1499 1500 /* Configuration looks good, so exit if in test mode. */ 1501 if (test_flag) 1502 exit(0); 1503 1504 if (rexec_flag) { 1505 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); 1506 for (i = 0; i < rexec_argc; i++) { 1507 debug("rexec_argv[%d]='%s'", i, saved_argv[i]); 1508 rexec_argv[i] = saved_argv[i]; 1509 } 1510 rexec_argv[rexec_argc] = "-R"; 1511 rexec_argv[rexec_argc + 1] = NULL; 1512 } 1513 1514 /* Ensure that umask disallows at least group and world write */ 1515 new_umask = umask(0077) | 0022; 1516 (void) umask(new_umask); 1517 1518 /* Initialize the log (it is reinitialized below in case we forked). */ 1519 if (debug_flag && (!inetd_flag || rexeced_flag)) 1520 log_stderr = 1; 1521 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1522 1523 /* 1524 * If not in debugging mode, and not started from inetd, disconnect 1525 * from the controlling terminal, and fork. The original process 1526 * exits. 1527 */ 1528 if (!(debug_flag || inetd_flag || no_daemon_flag)) { 1529 int fd; 1530 1531 if (daemon(0, 0) < 0) 1532 fatal("daemon() failed: %.200s", strerror(errno)); 1533 1534 /* Disconnect from the controlling tty. */ 1535 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); 1536 if (fd >= 0) { 1537 (void) ioctl(fd, TIOCNOTTY, NULL); 1538 close(fd); 1539 } 1540 } 1541 /* Reinitialize the log (because of the fork above). */ 1542 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1543 1544 /* Initialize the random number generator. */ 1545 arc4random_stir(); 1546 1547 /* Chdir to the root directory so that the current disk can be 1548 unmounted if desired. */ 1549 chdir("/"); 1550 1551 /* ignore SIGPIPE */ 1552 signal(SIGPIPE, SIG_IGN); 1553 1554 /* Get a connection, either from inetd or a listening TCP socket */ 1555 if (inetd_flag) { 1556 server_accept_inetd(&sock_in, &sock_out); 1557 } else { 1558 server_listen(); 1559 1560 if (options.protocol & SSH_PROTO_1) 1561 generate_ephemeral_server_key(); 1562 1563 signal(SIGHUP, sighup_handler); 1564 signal(SIGCHLD, main_sigchld_handler); 1565 signal(SIGTERM, sigterm_handler); 1566 signal(SIGQUIT, sigterm_handler); 1567 1568 /* 1569 * Write out the pid file after the sigterm handler 1570 * is setup and the listen sockets are bound 1571 */ 1572 if (!debug_flag) { 1573 FILE *f = fopen(options.pid_file, "w"); 1574 1575 if (f == NULL) { 1576 error("Couldn't create pid file \"%s\": %s", 1577 options.pid_file, strerror(errno)); 1578 } else { 1579 fprintf(f, "%ld\n", (long) getpid()); 1580 fclose(f); 1581 } 1582 } 1583 1584 /* Accept a connection and return in a forked child */ 1585 server_accept_loop(&sock_in, &sock_out, 1586 &newsock, config_s); 1587 } 1588 1589 /* This is the child processing a new connection. */ 1590 setproctitle("%s", "[accepted]"); 1591 1592 /* 1593 * Create a new session and process group since the 4.4BSD 1594 * setlogin() affects the entire process group. We don't 1595 * want the child to be able to affect the parent. 1596 */ 1597 if (!debug_flag && !inetd_flag && setsid() < 0) 1598 error("setsid: %.100s", strerror(errno)); 1599 1600 if (rexec_flag) { 1601 int fd; 1602 1603 debug("rexec start in %d out %d newsock %d pipe %d sock %d", 1604 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 1605 dup2(newsock, STDIN_FILENO); 1606 dup2(STDIN_FILENO, STDOUT_FILENO); 1607 if (startup_pipe == -1) 1608 close(REEXEC_STARTUP_PIPE_FD); 1609 else 1610 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); 1611 1612 dup2(config_s[1], REEXEC_CONFIG_PASS_FD); 1613 close(config_s[1]); 1614 if (startup_pipe != -1) 1615 close(startup_pipe); 1616 1617 execv(rexec_argv[0], rexec_argv); 1618 1619 /* Reexec has failed, fall back and continue */ 1620 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); 1621 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); 1622 log_init(__progname, options.log_level, 1623 options.log_facility, log_stderr); 1624 1625 /* Clean up fds */ 1626 startup_pipe = REEXEC_STARTUP_PIPE_FD; 1627 close(config_s[1]); 1628 close(REEXEC_CONFIG_PASS_FD); 1629 newsock = sock_out = sock_in = dup(STDIN_FILENO); 1630 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1631 dup2(fd, STDIN_FILENO); 1632 dup2(fd, STDOUT_FILENO); 1633 if (fd > STDERR_FILENO) 1634 close(fd); 1635 } 1636 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", 1637 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 1638 } 1639 1640 /* 1641 * Disable the key regeneration alarm. We will not regenerate the 1642 * key since we are no longer in a position to give it to anyone. We 1643 * will not restart on SIGHUP since it no longer makes sense. 1644 */ 1645 alarm(0); 1646 signal(SIGALRM, SIG_DFL); 1647 signal(SIGHUP, SIG_DFL); 1648 signal(SIGTERM, SIG_DFL); 1649 signal(SIGQUIT, SIG_DFL); 1650 signal(SIGCHLD, SIG_DFL); 1651 1652 /* 1653 * Register our connection. This turns encryption off because we do 1654 * not have a key. 1655 */ 1656 packet_set_connection(sock_in, sock_out); 1657 packet_set_server(); 1658 1659 /* Set SO_KEEPALIVE if requested. */ 1660 if (options.tcp_keep_alive && packet_connection_is_on_socket() && 1661 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) 1662 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 1663 1664 if ((remote_port = get_remote_port()) < 0) { 1665 debug("get_remote_port failed"); 1666 cleanup_exit(255); 1667 } 1668 1669 /* 1670 * We use get_canonical_hostname with usedns = 0 instead of 1671 * get_remote_ipaddr here so IP options will be checked. 1672 */ 1673 (void) get_canonical_hostname(0); 1674 /* 1675 * The rest of the code depends on the fact that 1676 * get_remote_ipaddr() caches the remote ip, even if 1677 * the socket goes away. 1678 */ 1679 remote_ip = get_remote_ipaddr(); 1680 1681 #ifdef LIBWRAP 1682 /* Check whether logins are denied from this host. */ 1683 if (packet_connection_is_on_socket()) { 1684 struct request_info req; 1685 1686 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); 1687 fromhost(&req); 1688 1689 if (!hosts_access(&req)) { 1690 debug("Connection refused by tcp wrapper"); 1691 refuse(&req); 1692 /* NOTREACHED */ 1693 fatal("libwrap refuse returns"); 1694 } 1695 } 1696 #endif /* LIBWRAP */ 1697 1698 /* Log the connection. */ 1699 verbose("Connection from %.500s port %d", remote_ip, remote_port); 1700 1701 /* 1702 * We don't want to listen forever unless the other side 1703 * successfully authenticates itself. So we set up an alarm which is 1704 * cleared after successful authentication. A limit of zero 1705 * indicates no limit. Note that we don't set the alarm in debugging 1706 * mode; it is just annoying to have the server exit just when you 1707 * are about to discover the bug. 1708 */ 1709 signal(SIGALRM, grace_alarm_handler); 1710 if (!debug_flag) 1711 alarm(options.login_grace_time); 1712 1713 sshd_exchange_identification(sock_in, sock_out); 1714 1715 /* In inetd mode, generate ephemeral key only for proto 1 connections */ 1716 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL) 1717 generate_ephemeral_server_key(); 1718 1719 packet_set_nonblocking(); 1720 1721 /* allocate authentication context */ 1722 authctxt = xcalloc(1, sizeof(*authctxt)); 1723 1724 /* XXX global for cleanup, access from other modules */ 1725 the_authctxt = authctxt; 1726 1727 /* prepare buffer to collect messages to display to user after login */ 1728 buffer_init(&loginmsg); 1729 1730 if (use_privsep) 1731 if (privsep_preauth(authctxt) == 1) 1732 goto authenticated; 1733 1734 /* perform the key exchange */ 1735 /* authenticate user and start session */ 1736 if (compat20) { 1737 do_ssh2_kex(); 1738 do_authentication2(authctxt); 1739 } else { 1740 do_ssh1_kex(); 1741 do_authentication(authctxt); 1742 } 1743 /* 1744 * If we use privilege separation, the unprivileged child transfers 1745 * the current keystate and exits 1746 */ 1747 if (use_privsep) { 1748 mm_send_keystate(pmonitor); 1749 exit(0); 1750 } 1751 1752 authenticated: 1753 /* 1754 * Cancel the alarm we set to limit the time taken for 1755 * authentication. 1756 */ 1757 alarm(0); 1758 signal(SIGALRM, SIG_DFL); 1759 authctxt->authenticated = 1; 1760 if (startup_pipe != -1) { 1761 close(startup_pipe); 1762 startup_pipe = -1; 1763 } 1764 1765 /* 1766 * In privilege separation, we fork another child and prepare 1767 * file descriptor passing. 1768 */ 1769 if (use_privsep) { 1770 privsep_postauth(authctxt); 1771 /* the monitor process [priv] will not return */ 1772 if (!compat20) 1773 destroy_sensitive_data(); 1774 } 1775 1776 packet_set_timeout(options.client_alive_interval, 1777 options.client_alive_count_max); 1778 1779 /* Start session. */ 1780 do_authenticated(authctxt); 1781 1782 /* The connection has been terminated. */ 1783 packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); 1784 packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); 1785 verbose("Transferred: sent %llu, received %llu bytes", obytes, ibytes); 1786 1787 verbose("Closing connection to %.500s port %d", remote_ip, remote_port); 1788 packet_close(); 1789 1790 if (use_privsep) 1791 mm_terminate(); 1792 1793 exit(0); 1794 } 1795 1796 /* 1797 * Decrypt session_key_int using our private server key and private host key 1798 * (key with larger modulus first). 1799 */ 1800 int 1801 ssh1_session_key(BIGNUM *session_key_int) 1802 { 1803 int rsafail = 0; 1804 1805 if (BN_cmp(sensitive_data.server_key->rsa->n, 1806 sensitive_data.ssh1_host_key->rsa->n) > 0) { 1807 /* Server key has bigger modulus. */ 1808 if (BN_num_bits(sensitive_data.server_key->rsa->n) < 1809 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + 1810 SSH_KEY_BITS_RESERVED) { 1811 fatal("do_connection: %s: " 1812 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", 1813 get_remote_ipaddr(), 1814 BN_num_bits(sensitive_data.server_key->rsa->n), 1815 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 1816 SSH_KEY_BITS_RESERVED); 1817 } 1818 if (rsa_private_decrypt(session_key_int, session_key_int, 1819 sensitive_data.server_key->rsa) <= 0) 1820 rsafail++; 1821 if (rsa_private_decrypt(session_key_int, session_key_int, 1822 sensitive_data.ssh1_host_key->rsa) <= 0) 1823 rsafail++; 1824 } else { 1825 /* Host key has bigger modulus (or they are equal). */ 1826 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < 1827 BN_num_bits(sensitive_data.server_key->rsa->n) + 1828 SSH_KEY_BITS_RESERVED) { 1829 fatal("do_connection: %s: " 1830 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", 1831 get_remote_ipaddr(), 1832 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), 1833 BN_num_bits(sensitive_data.server_key->rsa->n), 1834 SSH_KEY_BITS_RESERVED); 1835 } 1836 if (rsa_private_decrypt(session_key_int, session_key_int, 1837 sensitive_data.ssh1_host_key->rsa) < 0) 1838 rsafail++; 1839 if (rsa_private_decrypt(session_key_int, session_key_int, 1840 sensitive_data.server_key->rsa) < 0) 1841 rsafail++; 1842 } 1843 return (rsafail); 1844 } 1845 /* 1846 * SSH1 key exchange 1847 */ 1848 static void 1849 do_ssh1_kex(void) 1850 { 1851 int i, len; 1852 int rsafail = 0; 1853 BIGNUM *session_key_int; 1854 u_char session_key[SSH_SESSION_KEY_LENGTH]; 1855 u_char cookie[8]; 1856 u_int cipher_type, auth_mask, protocol_flags; 1857 1858 /* 1859 * Generate check bytes that the client must send back in the user 1860 * packet in order for it to be accepted; this is used to defy ip 1861 * spoofing attacks. Note that this only works against somebody 1862 * doing IP spoofing from a remote machine; any machine on the local 1863 * network can still see outgoing packets and catch the random 1864 * cookie. This only affects rhosts authentication, and this is one 1865 * of the reasons why it is inherently insecure. 1866 */ 1867 arc4random_buf(cookie, sizeof(cookie)); 1868 1869 /* 1870 * Send our public key. We include in the packet 64 bits of random 1871 * data that must be matched in the reply in order to prevent IP 1872 * spoofing. 1873 */ 1874 packet_start(SSH_SMSG_PUBLIC_KEY); 1875 for (i = 0; i < 8; i++) 1876 packet_put_char(cookie[i]); 1877 1878 /* Store our public server RSA key. */ 1879 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); 1880 packet_put_bignum(sensitive_data.server_key->rsa->e); 1881 packet_put_bignum(sensitive_data.server_key->rsa->n); 1882 1883 /* Store our public host RSA key. */ 1884 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 1885 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); 1886 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); 1887 1888 /* Put protocol flags. */ 1889 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); 1890 1891 /* Declare which ciphers we support. */ 1892 packet_put_int(cipher_mask_ssh1(0)); 1893 1894 /* Declare supported authentication types. */ 1895 auth_mask = 0; 1896 if (options.rhosts_rsa_authentication) 1897 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; 1898 if (options.rsa_authentication) 1899 auth_mask |= 1 << SSH_AUTH_RSA; 1900 if (options.challenge_response_authentication == 1) 1901 auth_mask |= 1 << SSH_AUTH_TIS; 1902 if (options.password_authentication) 1903 auth_mask |= 1 << SSH_AUTH_PASSWORD; 1904 packet_put_int(auth_mask); 1905 1906 /* Send the packet and wait for it to be sent. */ 1907 packet_send(); 1908 packet_write_wait(); 1909 1910 debug("Sent %d bit server key and %d bit host key.", 1911 BN_num_bits(sensitive_data.server_key->rsa->n), 1912 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); 1913 1914 /* Read clients reply (cipher type and session key). */ 1915 packet_read_expect(SSH_CMSG_SESSION_KEY); 1916 1917 /* Get cipher type and check whether we accept this. */ 1918 cipher_type = packet_get_char(); 1919 1920 if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) 1921 packet_disconnect("Warning: client selects unsupported cipher."); 1922 1923 /* Get check bytes from the packet. These must match those we 1924 sent earlier with the public key packet. */ 1925 for (i = 0; i < 8; i++) 1926 if (cookie[i] != packet_get_char()) 1927 packet_disconnect("IP Spoofing check bytes do not match."); 1928 1929 debug("Encryption type: %.200s", cipher_name(cipher_type)); 1930 1931 /* Get the encrypted integer. */ 1932 if ((session_key_int = BN_new()) == NULL) 1933 fatal("do_ssh1_kex: BN_new failed"); 1934 packet_get_bignum(session_key_int); 1935 1936 protocol_flags = packet_get_int(); 1937 packet_set_protocol_flags(protocol_flags); 1938 packet_check_eom(); 1939 1940 /* Decrypt session_key_int using host/server keys */ 1941 rsafail = PRIVSEP(ssh1_session_key(session_key_int)); 1942 1943 /* 1944 * Extract session key from the decrypted integer. The key is in the 1945 * least significant 256 bits of the integer; the first byte of the 1946 * key is in the highest bits. 1947 */ 1948 if (!rsafail) { 1949 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8); 1950 len = BN_num_bytes(session_key_int); 1951 if (len < 0 || (u_int)len > sizeof(session_key)) { 1952 error("do_ssh1_kex: bad session key len from %s: " 1953 "session_key_int %d > sizeof(session_key) %lu", 1954 get_remote_ipaddr(), len, (u_long)sizeof(session_key)); 1955 rsafail++; 1956 } else { 1957 memset(session_key, 0, sizeof(session_key)); 1958 BN_bn2bin(session_key_int, 1959 session_key + sizeof(session_key) - len); 1960 1961 derive_ssh1_session_id( 1962 sensitive_data.ssh1_host_key->rsa->n, 1963 sensitive_data.server_key->rsa->n, 1964 cookie, session_id); 1965 /* 1966 * Xor the first 16 bytes of the session key with the 1967 * session id. 1968 */ 1969 for (i = 0; i < 16; i++) 1970 session_key[i] ^= session_id[i]; 1971 } 1972 } 1973 if (rsafail) { 1974 int bytes = BN_num_bytes(session_key_int); 1975 u_char *buf = xmalloc(bytes); 1976 MD5_CTX md; 1977 1978 logit("do_connection: generating a fake encryption key"); 1979 BN_bn2bin(session_key_int, buf); 1980 MD5_Init(&md); 1981 MD5_Update(&md, buf, bytes); 1982 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); 1983 MD5_Final(session_key, &md); 1984 MD5_Init(&md); 1985 MD5_Update(&md, session_key, 16); 1986 MD5_Update(&md, buf, bytes); 1987 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); 1988 MD5_Final(session_key + 16, &md); 1989 memset(buf, 0, bytes); 1990 xfree(buf); 1991 for (i = 0; i < 16; i++) 1992 session_id[i] = session_key[i] ^ session_key[i + 16]; 1993 } 1994 /* Destroy the private and public keys. No longer. */ 1995 destroy_sensitive_data(); 1996 1997 if (use_privsep) 1998 mm_ssh1_session_id(session_id); 1999 2000 /* Destroy the decrypted integer. It is no longer needed. */ 2001 BN_clear_free(session_key_int); 2002 2003 /* Set the session key. From this on all communications will be encrypted. */ 2004 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); 2005 2006 /* Destroy our copy of the session key. It is no longer needed. */ 2007 memset(session_key, 0, sizeof(session_key)); 2008 2009 debug("Received session key; encryption turned on."); 2010 2011 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ 2012 packet_start(SSH_SMSG_SUCCESS); 2013 packet_send(); 2014 packet_write_wait(); 2015 } 2016 2017 /* 2018 * SSH2 key exchange: diffie-hellman-group1-sha1 2019 */ 2020 static void 2021 do_ssh2_kex(void) 2022 { 2023 Kex *kex; 2024 2025 if (options.ciphers != NULL) { 2026 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 2027 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 2028 } 2029 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 2030 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 2031 myproposal[PROPOSAL_ENC_ALGS_STOC] = 2032 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 2033 2034 if (options.macs != NULL) { 2035 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 2036 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 2037 } 2038 if (options.compression == COMP_NONE) { 2039 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2040 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; 2041 } else if (options.compression == COMP_DELAYED) { 2042 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2043 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; 2044 } 2045 2046 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); 2047 2048 /* start key exchange */ 2049 kex = kex_setup(myproposal); 2050 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 2051 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 2052 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 2053 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 2054 kex->server = 1; 2055 kex->client_version_string=client_version_string; 2056 kex->server_version_string=server_version_string; 2057 kex->load_host_key=&get_hostkey_by_type; 2058 kex->host_key_index=&get_hostkey_index; 2059 2060 xxx_kex = kex; 2061 2062 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 2063 2064 session_id2 = kex->session_id; 2065 session_id2_len = kex->session_id_len; 2066 2067 #ifdef DEBUG_KEXDH 2068 /* send 1st encrypted/maced/compressed message */ 2069 packet_start(SSH2_MSG_IGNORE); 2070 packet_put_cstring("markus"); 2071 packet_send(); 2072 packet_write_wait(); 2073 #endif 2074 debug("KEX done"); 2075 } 2076 2077 /* server specific fatal cleanup */ 2078 void 2079 cleanup_exit(int i) 2080 { 2081 if (the_authctxt) 2082 do_cleanup(the_authctxt); 2083 _exit(i); 2084 } 2085