1 /* $OpenBSD: sshd.c,v 1.492 2017/09/12 06:32:07 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This program is the ssh daemon. It listens for connections from clients, 7 * and performs authentication, executes use commands or shell, and forwards 8 * information to/from the application to the user client over an encrypted 9 * connection. This can also handle forwarding of X11, TCP/IP, and 10 * authentication agent connections. 11 * 12 * As far as I am concerned, the code I have written for this software 13 * can be used freely for any purpose. Any derived versions of this 14 * software must be clearly marked as such, and if the derived work is 15 * incompatible with the protocol description in the RFC file, it must be 16 * called by a name other than "ssh" or "Secure Shell". 17 * 18 * SSH2 implementation: 19 * Privilege Separation: 20 * 21 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. 22 * Copyright (c) 2002 Niels Provos. All rights reserved. 23 * 24 * Redistribution and use in source and binary forms, with or without 25 * modification, are permitted provided that the following conditions 26 * are met: 27 * 1. Redistributions of source code must retain the above copyright 28 * notice, this list of conditions and the following disclaimer. 29 * 2. Redistributions in binary form must reproduce the above copyright 30 * notice, this list of conditions and the following disclaimer in the 31 * documentation and/or other materials provided with the distribution. 32 * 33 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 34 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 35 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 36 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 37 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 39 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 40 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 42 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 43 */ 44 45 #include "includes.h" 46 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 "ssh2.h" 91 #include "sshpty.h" 92 #include "packet.h" 93 #include "log.h" 94 #include "buffer.h" 95 #include "misc.h" 96 #include "match.h" 97 #include "servconf.h" 98 #include "uidswap.h" 99 #include "compat.h" 100 #include "cipher.h" 101 #include "digest.h" 102 #include "key.h" 103 #include "kex.h" 104 #include "myproposal.h" 105 #include "authfile.h" 106 #include "pathnames.h" 107 #include "atomicio.h" 108 #include "canohost.h" 109 #include "hostfile.h" 110 #include "auth.h" 111 #include "authfd.h" 112 #include "msg.h" 113 #include "dispatch.h" 114 #include "channels.h" 115 #include "session.h" 116 #include "monitor.h" 117 #ifdef GSSAPI 118 #include "ssh-gss.h" 119 #endif 120 #include "monitor_wrap.h" 121 #include "ssh-sandbox.h" 122 #include "version.h" 123 #include "ssherr.h" 124 125 /* Re-exec fds */ 126 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) 127 #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) 128 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) 129 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) 130 131 extern char *__progname; 132 133 /* Server configuration options. */ 134 ServerOptions options; 135 136 /* Name of the server configuration file. */ 137 char *config_file_name = _PATH_SERVER_CONFIG_FILE; 138 139 /* 140 * Debug mode flag. This can be set on the command line. If debug 141 * mode is enabled, extra debugging output will be sent to the system 142 * log, the daemon will not go to background, and will exit after processing 143 * the first connection. 144 */ 145 int debug_flag = 0; 146 147 /* Flag indicating that the daemon should only test the configuration and keys. */ 148 int test_flag = 0; 149 150 /* Flag indicating that the daemon is being started from inetd. */ 151 int inetd_flag = 0; 152 153 /* Flag indicating that sshd should not detach and become a daemon. */ 154 int no_daemon_flag = 0; 155 156 /* debug goes to stderr unless inetd_flag is set */ 157 int log_stderr = 0; 158 159 /* Saved arguments to main(). */ 160 char **saved_argv; 161 int saved_argc; 162 163 /* re-exec */ 164 int rexeced_flag = 0; 165 int rexec_flag = 1; 166 int rexec_argc = 0; 167 char **rexec_argv; 168 169 /* 170 * The sockets that the server is listening; this is used in the SIGHUP 171 * signal handler. 172 */ 173 #define MAX_LISTEN_SOCKS 16 174 int listen_socks[MAX_LISTEN_SOCKS]; 175 int num_listen_socks = 0; 176 177 /* 178 * the client's version string, passed by sshd2 in compat mode. if != NULL, 179 * sshd will skip the version-number exchange 180 */ 181 char *client_version_string = NULL; 182 char *server_version_string = NULL; 183 184 /* Daemon's agent connection */ 185 int auth_sock = -1; 186 int have_agent = 0; 187 188 /* 189 * Any really sensitive data in the application is contained in this 190 * structure. The idea is that this structure could be locked into memory so 191 * that the pages do not get written into swap. However, there are some 192 * problems. The private key contains BIGNUMs, and we do not (in principle) 193 * have access to the internals of them, and locking just the structure is 194 * not very useful. Currently, memory locking is not implemented. 195 */ 196 struct { 197 struct sshkey **host_keys; /* all private host keys */ 198 struct sshkey **host_pubkeys; /* all public host keys */ 199 struct sshkey **host_certificates; /* all public host certificates */ 200 int have_ssh2_key; 201 } sensitive_data; 202 203 /* This is set to true when a signal is received. */ 204 static volatile sig_atomic_t received_sighup = 0; 205 static volatile sig_atomic_t received_sigterm = 0; 206 207 /* session identifier, used by RSA-auth */ 208 u_char session_id[16]; 209 210 /* same for ssh2 */ 211 u_char *session_id2 = NULL; 212 u_int session_id2_len = 0; 213 214 /* record remote hostname or ip */ 215 u_int utmp_len = HOST_NAME_MAX+1; 216 217 /* options.max_startup sized array of fd ints */ 218 int *startup_pipes = NULL; 219 int startup_pipe; /* in child */ 220 221 /* variables used for privilege separation */ 222 int use_privsep = -1; 223 struct monitor *pmonitor = NULL; 224 int privsep_is_preauth = 1; 225 static int privsep_chroot = 1; 226 227 /* global authentication context */ 228 Authctxt *the_authctxt = NULL; 229 230 /* sshd_config buffer */ 231 Buffer cfg; 232 233 /* message to be displayed after login */ 234 Buffer loginmsg; 235 236 /* Unprivileged user */ 237 struct passwd *privsep_pw = NULL; 238 239 /* Prototypes for various functions defined later in this file. */ 240 void destroy_sensitive_data(void); 241 void demote_sensitive_data(void); 242 static void do_ssh2_kex(void); 243 244 /* 245 * Close all listening sockets 246 */ 247 static void 248 close_listen_socks(void) 249 { 250 int i; 251 252 for (i = 0; i < num_listen_socks; i++) 253 close(listen_socks[i]); 254 num_listen_socks = -1; 255 } 256 257 static void 258 close_startup_pipes(void) 259 { 260 int i; 261 262 if (startup_pipes) 263 for (i = 0; i < options.max_startups; i++) 264 if (startup_pipes[i] != -1) 265 close(startup_pipes[i]); 266 } 267 268 /* 269 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; 270 * the effect is to reread the configuration file (and to regenerate 271 * the server key). 272 */ 273 274 /*ARGSUSED*/ 275 static void 276 sighup_handler(int sig) 277 { 278 int save_errno = errno; 279 280 received_sighup = 1; 281 signal(SIGHUP, sighup_handler); 282 errno = save_errno; 283 } 284 285 /* 286 * Called from the main program after receiving SIGHUP. 287 * Restarts the server. 288 */ 289 static void 290 sighup_restart(void) 291 { 292 logit("Received SIGHUP; restarting."); 293 if (options.pid_file != NULL) 294 unlink(options.pid_file); 295 platform_pre_restart(); 296 close_listen_socks(); 297 close_startup_pipes(); 298 alarm(0); /* alarm timer persists across exec */ 299 signal(SIGHUP, SIG_IGN); /* will be restored after exec */ 300 execv(saved_argv[0], saved_argv); 301 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], 302 strerror(errno)); 303 exit(1); 304 } 305 306 /* 307 * Generic signal handler for terminating signals in the master daemon. 308 */ 309 /*ARGSUSED*/ 310 static void 311 sigterm_handler(int sig) 312 { 313 received_sigterm = sig; 314 } 315 316 /* 317 * SIGCHLD handler. This is called whenever a child dies. This will then 318 * reap any zombies left by exited children. 319 */ 320 /*ARGSUSED*/ 321 static void 322 main_sigchld_handler(int sig) 323 { 324 int save_errno = errno; 325 pid_t pid; 326 int status; 327 328 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || 329 (pid < 0 && errno == EINTR)) 330 ; 331 332 signal(SIGCHLD, main_sigchld_handler); 333 errno = save_errno; 334 } 335 336 /* 337 * Signal handler for the alarm after the login grace period has expired. 338 */ 339 /*ARGSUSED*/ 340 static void 341 grace_alarm_handler(int sig) 342 { 343 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) 344 kill(pmonitor->m_pid, SIGALRM); 345 346 /* 347 * Try to kill any processes that we have spawned, E.g. authorized 348 * keys command helpers. 349 */ 350 if (getpgid(0) == getpid()) { 351 signal(SIGTERM, SIG_IGN); 352 kill(0, SIGTERM); 353 } 354 355 /* Log error and exit. */ 356 sigdie("Timeout before authentication for %s port %d", 357 ssh_remote_ipaddr(active_state), ssh_remote_port(active_state)); 358 } 359 360 static void 361 sshd_exchange_identification(struct ssh *ssh, int sock_in, int sock_out) 362 { 363 u_int i; 364 int remote_major, remote_minor; 365 char *s; 366 char buf[256]; /* Must not be larger than remote_version. */ 367 char remote_version[256]; /* Must be at least as big as buf. */ 368 369 xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s\r\n", 370 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION, 371 *options.version_addendum == '\0' ? "" : " ", 372 options.version_addendum); 373 374 /* Send our protocol version identification. */ 375 if (atomicio(vwrite, sock_out, server_version_string, 376 strlen(server_version_string)) 377 != strlen(server_version_string)) { 378 logit("Could not write ident string to %s port %d", 379 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 380 cleanup_exit(255); 381 } 382 383 /* Read other sides version identification. */ 384 memset(buf, 0, sizeof(buf)); 385 for (i = 0; i < sizeof(buf) - 1; i++) { 386 if (atomicio(read, sock_in, &buf[i], 1) != 1) { 387 logit("Did not receive identification string " 388 "from %s port %d", 389 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 390 cleanup_exit(255); 391 } 392 if (buf[i] == '\r') { 393 buf[i] = 0; 394 /* Kludge for F-Secure Macintosh < 1.0.2 */ 395 if (i == 12 && 396 strncmp(buf, "SSH-1.5-W1.0", 12) == 0) 397 break; 398 continue; 399 } 400 if (buf[i] == '\n') { 401 buf[i] = 0; 402 break; 403 } 404 } 405 buf[sizeof(buf) - 1] = 0; 406 client_version_string = xstrdup(buf); 407 408 /* 409 * Check that the versions match. In future this might accept 410 * several versions and set appropriate flags to handle them. 411 */ 412 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", 413 &remote_major, &remote_minor, remote_version) != 3) { 414 s = "Protocol mismatch.\n"; 415 (void) atomicio(vwrite, sock_out, s, strlen(s)); 416 logit("Bad protocol version identification '%.100s' " 417 "from %s port %d", client_version_string, 418 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 419 close(sock_in); 420 close(sock_out); 421 cleanup_exit(255); 422 } 423 debug("Client protocol version %d.%d; client software version %.100s", 424 remote_major, remote_minor, remote_version); 425 426 ssh->compat = compat_datafellows(remote_version); 427 428 if ((ssh->compat & SSH_BUG_PROBE) != 0) { 429 logit("probed from %s port %d with %s. Don't panic.", 430 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 431 client_version_string); 432 cleanup_exit(255); 433 } 434 if ((ssh->compat & SSH_BUG_SCANNER) != 0) { 435 logit("scanned from %s port %d with %s. Don't panic.", 436 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 437 client_version_string); 438 cleanup_exit(255); 439 } 440 if ((ssh->compat & SSH_BUG_RSASIGMD5) != 0) { 441 logit("Client version \"%.100s\" uses unsafe RSA signature " 442 "scheme; disabling use of RSA keys", remote_version); 443 } 444 if ((ssh->compat & SSH_BUG_DERIVEKEY) != 0) { 445 fatal("Client version \"%.100s\" uses unsafe key agreement; " 446 "refusing connection", remote_version); 447 } 448 449 chop(server_version_string); 450 debug("Local version string %.200s", server_version_string); 451 452 if (remote_major != 2 || 453 (remote_major == 1 && remote_minor != 99)) { 454 s = "Protocol major versions differ.\n"; 455 (void) atomicio(vwrite, sock_out, s, strlen(s)); 456 close(sock_in); 457 close(sock_out); 458 logit("Protocol major versions differ for %s port %d: " 459 "%.200s vs. %.200s", 460 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 461 server_version_string, client_version_string); 462 cleanup_exit(255); 463 } 464 } 465 466 /* Destroy the host and server keys. They will no longer be needed. */ 467 void 468 destroy_sensitive_data(void) 469 { 470 int i; 471 472 for (i = 0; i < options.num_host_key_files; i++) { 473 if (sensitive_data.host_keys[i]) { 474 key_free(sensitive_data.host_keys[i]); 475 sensitive_data.host_keys[i] = NULL; 476 } 477 if (sensitive_data.host_certificates[i]) { 478 key_free(sensitive_data.host_certificates[i]); 479 sensitive_data.host_certificates[i] = NULL; 480 } 481 } 482 } 483 484 /* Demote private to public keys for network child */ 485 void 486 demote_sensitive_data(void) 487 { 488 struct sshkey *tmp; 489 int i; 490 491 for (i = 0; i < options.num_host_key_files; i++) { 492 if (sensitive_data.host_keys[i]) { 493 tmp = key_demote(sensitive_data.host_keys[i]); 494 key_free(sensitive_data.host_keys[i]); 495 sensitive_data.host_keys[i] = tmp; 496 } 497 /* Certs do not need demotion */ 498 } 499 } 500 501 static void 502 reseed_prngs(void) 503 { 504 u_int32_t rnd[256]; 505 506 #ifdef WITH_OPENSSL 507 RAND_poll(); 508 #endif 509 arc4random_stir(); /* noop on recent arc4random() implementations */ 510 arc4random_buf(rnd, sizeof(rnd)); /* let arc4random notice PID change */ 511 512 #ifdef WITH_OPENSSL 513 RAND_seed(rnd, sizeof(rnd)); 514 /* give libcrypto a chance to notice the PID change */ 515 if ((RAND_bytes((u_char *)rnd, 1)) != 1) 516 fatal("%s: RAND_bytes failed", __func__); 517 #endif 518 519 explicit_bzero(rnd, sizeof(rnd)); 520 } 521 522 static void 523 privsep_preauth_child(void) 524 { 525 gid_t gidset[1]; 526 527 /* Enable challenge-response authentication for privilege separation */ 528 privsep_challenge_enable(); 529 530 #ifdef GSSAPI 531 /* Cache supported mechanism OIDs for later use */ 532 if (options.gss_authentication) 533 ssh_gssapi_prepare_supported_oids(); 534 #endif 535 536 reseed_prngs(); 537 538 /* Demote the private keys to public keys. */ 539 demote_sensitive_data(); 540 541 /* Demote the child */ 542 if (privsep_chroot) { 543 /* Change our root directory */ 544 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) 545 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, 546 strerror(errno)); 547 if (chdir("/") == -1) 548 fatal("chdir(\"/\"): %s", strerror(errno)); 549 550 /* Drop our privileges */ 551 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid, 552 (u_int)privsep_pw->pw_gid); 553 gidset[0] = privsep_pw->pw_gid; 554 if (setgroups(1, gidset) < 0) 555 fatal("setgroups: %.100s", strerror(errno)); 556 permanently_set_uid(privsep_pw); 557 } 558 } 559 560 static int 561 privsep_preauth(Authctxt *authctxt) 562 { 563 int status, r; 564 pid_t pid; 565 struct ssh_sandbox *box = NULL; 566 567 /* Set up unprivileged child process to deal with network data */ 568 pmonitor = monitor_init(); 569 /* Store a pointer to the kex for later rekeying */ 570 pmonitor->m_pkex = &active_state->kex; 571 572 if (use_privsep == PRIVSEP_ON) 573 box = ssh_sandbox_init(pmonitor); 574 pid = fork(); 575 if (pid == -1) { 576 fatal("fork of unprivileged child failed"); 577 } else if (pid != 0) { 578 debug2("Network child is on pid %ld", (long)pid); 579 580 pmonitor->m_pid = pid; 581 if (have_agent) { 582 r = ssh_get_authentication_socket(&auth_sock); 583 if (r != 0) { 584 error("Could not get agent socket: %s", 585 ssh_err(r)); 586 have_agent = 0; 587 } 588 } 589 if (box != NULL) 590 ssh_sandbox_parent_preauth(box, pid); 591 monitor_child_preauth(authctxt, pmonitor); 592 593 /* Wait for the child's exit status */ 594 while (waitpid(pid, &status, 0) < 0) { 595 if (errno == EINTR) 596 continue; 597 pmonitor->m_pid = -1; 598 fatal("%s: waitpid: %s", __func__, strerror(errno)); 599 } 600 privsep_is_preauth = 0; 601 pmonitor->m_pid = -1; 602 if (WIFEXITED(status)) { 603 if (WEXITSTATUS(status) != 0) 604 fatal("%s: preauth child exited with status %d", 605 __func__, WEXITSTATUS(status)); 606 } else if (WIFSIGNALED(status)) 607 fatal("%s: preauth child terminated by signal %d", 608 __func__, WTERMSIG(status)); 609 if (box != NULL) 610 ssh_sandbox_parent_finish(box); 611 return 1; 612 } else { 613 /* child */ 614 close(pmonitor->m_sendfd); 615 close(pmonitor->m_log_recvfd); 616 617 /* Arrange for logging to be sent to the monitor */ 618 set_log_handler(mm_log_handler, pmonitor); 619 620 privsep_preauth_child(); 621 setproctitle("%s", "[net]"); 622 if (box != NULL) 623 ssh_sandbox_child(box); 624 625 return 0; 626 } 627 } 628 629 static void 630 privsep_postauth(Authctxt *authctxt) 631 { 632 #ifdef DISABLE_FD_PASSING 633 if (1) { 634 #else 635 if (authctxt->pw->pw_uid == 0) { 636 #endif 637 /* File descriptor passing is broken or root login */ 638 use_privsep = 0; 639 goto skip; 640 } 641 642 /* New socket pair */ 643 monitor_reinit(pmonitor); 644 645 pmonitor->m_pid = fork(); 646 if (pmonitor->m_pid == -1) 647 fatal("fork of unprivileged child failed"); 648 else if (pmonitor->m_pid != 0) { 649 verbose("User child is on pid %ld", (long)pmonitor->m_pid); 650 buffer_clear(&loginmsg); 651 monitor_clear_keystate(pmonitor); 652 monitor_child_postauth(pmonitor); 653 654 /* NEVERREACHED */ 655 exit(0); 656 } 657 658 /* child */ 659 660 close(pmonitor->m_sendfd); 661 pmonitor->m_sendfd = -1; 662 663 /* Demote the private keys to public keys. */ 664 demote_sensitive_data(); 665 666 reseed_prngs(); 667 668 /* Drop privileges */ 669 do_setusercontext(authctxt->pw); 670 671 skip: 672 /* It is safe now to apply the key state */ 673 monitor_apply_keystate(pmonitor); 674 675 /* 676 * Tell the packet layer that authentication was successful, since 677 * this information is not part of the key state. 678 */ 679 packet_set_authenticated(); 680 } 681 682 static char * 683 list_hostkey_types(void) 684 { 685 Buffer b; 686 const char *p; 687 char *ret; 688 int i; 689 struct sshkey *key; 690 691 buffer_init(&b); 692 for (i = 0; i < options.num_host_key_files; i++) { 693 key = sensitive_data.host_keys[i]; 694 if (key == NULL) 695 key = sensitive_data.host_pubkeys[i]; 696 if (key == NULL) 697 continue; 698 /* Check that the key is accepted in HostkeyAlgorithms */ 699 if (match_pattern_list(sshkey_ssh_name(key), 700 options.hostkeyalgorithms, 0) != 1) { 701 debug3("%s: %s key not permitted by HostkeyAlgorithms", 702 __func__, sshkey_ssh_name(key)); 703 continue; 704 } 705 switch (key->type) { 706 case KEY_RSA: 707 case KEY_DSA: 708 case KEY_ECDSA: 709 case KEY_ED25519: 710 if (buffer_len(&b) > 0) 711 buffer_append(&b, ",", 1); 712 p = key_ssh_name(key); 713 buffer_append(&b, p, strlen(p)); 714 715 /* for RSA we also support SHA2 signatures */ 716 if (key->type == KEY_RSA) { 717 p = ",rsa-sha2-512,rsa-sha2-256"; 718 buffer_append(&b, p, strlen(p)); 719 } 720 break; 721 } 722 /* If the private key has a cert peer, then list that too */ 723 key = sensitive_data.host_certificates[i]; 724 if (key == NULL) 725 continue; 726 switch (key->type) { 727 case KEY_RSA_CERT: 728 case KEY_DSA_CERT: 729 case KEY_ECDSA_CERT: 730 case KEY_ED25519_CERT: 731 if (buffer_len(&b) > 0) 732 buffer_append(&b, ",", 1); 733 p = key_ssh_name(key); 734 buffer_append(&b, p, strlen(p)); 735 break; 736 } 737 } 738 if ((ret = sshbuf_dup_string(&b)) == NULL) 739 fatal("%s: sshbuf_dup_string failed", __func__); 740 buffer_free(&b); 741 debug("list_hostkey_types: %s", ret); 742 return ret; 743 } 744 745 static struct sshkey * 746 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh) 747 { 748 int i; 749 struct sshkey *key; 750 751 for (i = 0; i < options.num_host_key_files; i++) { 752 switch (type) { 753 case KEY_RSA_CERT: 754 case KEY_DSA_CERT: 755 case KEY_ECDSA_CERT: 756 case KEY_ED25519_CERT: 757 key = sensitive_data.host_certificates[i]; 758 break; 759 default: 760 key = sensitive_data.host_keys[i]; 761 if (key == NULL && !need_private) 762 key = sensitive_data.host_pubkeys[i]; 763 break; 764 } 765 if (key != NULL && key->type == type && 766 (key->type != KEY_ECDSA || key->ecdsa_nid == nid)) 767 return need_private ? 768 sensitive_data.host_keys[i] : key; 769 } 770 return NULL; 771 } 772 773 struct sshkey * 774 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh) 775 { 776 return get_hostkey_by_type(type, nid, 0, ssh); 777 } 778 779 struct sshkey * 780 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh) 781 { 782 return get_hostkey_by_type(type, nid, 1, ssh); 783 } 784 785 struct sshkey * 786 get_hostkey_by_index(int ind) 787 { 788 if (ind < 0 || ind >= options.num_host_key_files) 789 return (NULL); 790 return (sensitive_data.host_keys[ind]); 791 } 792 793 struct sshkey * 794 get_hostkey_public_by_index(int ind, struct ssh *ssh) 795 { 796 if (ind < 0 || ind >= options.num_host_key_files) 797 return (NULL); 798 return (sensitive_data.host_pubkeys[ind]); 799 } 800 801 int 802 get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh) 803 { 804 int i; 805 806 for (i = 0; i < options.num_host_key_files; i++) { 807 if (key_is_cert(key)) { 808 if (key == sensitive_data.host_certificates[i] || 809 (compare && sensitive_data.host_certificates[i] && 810 sshkey_equal(key, 811 sensitive_data.host_certificates[i]))) 812 return (i); 813 } else { 814 if (key == sensitive_data.host_keys[i] || 815 (compare && sensitive_data.host_keys[i] && 816 sshkey_equal(key, sensitive_data.host_keys[i]))) 817 return (i); 818 if (key == sensitive_data.host_pubkeys[i] || 819 (compare && sensitive_data.host_pubkeys[i] && 820 sshkey_equal(key, sensitive_data.host_pubkeys[i]))) 821 return (i); 822 } 823 } 824 return (-1); 825 } 826 827 /* Inform the client of all hostkeys */ 828 static void 829 notify_hostkeys(struct ssh *ssh) 830 { 831 struct sshbuf *buf; 832 struct sshkey *key; 833 int i, nkeys, r; 834 char *fp; 835 836 /* Some clients cannot cope with the hostkeys message, skip those. */ 837 if (datafellows & SSH_BUG_HOSTKEYS) 838 return; 839 840 if ((buf = sshbuf_new()) == NULL) 841 fatal("%s: sshbuf_new", __func__); 842 for (i = nkeys = 0; i < options.num_host_key_files; i++) { 843 key = get_hostkey_public_by_index(i, ssh); 844 if (key == NULL || key->type == KEY_UNSPEC || 845 sshkey_is_cert(key)) 846 continue; 847 fp = sshkey_fingerprint(key, options.fingerprint_hash, 848 SSH_FP_DEFAULT); 849 debug3("%s: key %d: %s %s", __func__, i, 850 sshkey_ssh_name(key), fp); 851 free(fp); 852 if (nkeys == 0) { 853 packet_start(SSH2_MSG_GLOBAL_REQUEST); 854 packet_put_cstring("hostkeys-00@openssh.com"); 855 packet_put_char(0); /* want-reply */ 856 } 857 sshbuf_reset(buf); 858 if ((r = sshkey_putb(key, buf)) != 0) 859 fatal("%s: couldn't put hostkey %d: %s", 860 __func__, i, ssh_err(r)); 861 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf)); 862 nkeys++; 863 } 864 debug3("%s: sent %d hostkeys", __func__, nkeys); 865 if (nkeys == 0) 866 fatal("%s: no hostkeys", __func__); 867 packet_send(); 868 sshbuf_free(buf); 869 } 870 871 /* 872 * returns 1 if connection should be dropped, 0 otherwise. 873 * dropping starts at connection #max_startups_begin with a probability 874 * of (max_startups_rate/100). the probability increases linearly until 875 * all connections are dropped for startups > max_startups 876 */ 877 static int 878 drop_connection(int startups) 879 { 880 int p, r; 881 882 if (startups < options.max_startups_begin) 883 return 0; 884 if (startups >= options.max_startups) 885 return 1; 886 if (options.max_startups_rate == 100) 887 return 1; 888 889 p = 100 - options.max_startups_rate; 890 p *= startups - options.max_startups_begin; 891 p /= options.max_startups - options.max_startups_begin; 892 p += options.max_startups_rate; 893 r = arc4random_uniform(100); 894 895 debug("drop_connection: p %d, r %d", p, r); 896 return (r < p) ? 1 : 0; 897 } 898 899 static void 900 usage(void) 901 { 902 fprintf(stderr, "%s, %s\n", 903 SSH_RELEASE, 904 #ifdef WITH_OPENSSL 905 SSLeay_version(SSLEAY_VERSION) 906 #else 907 "without OpenSSL" 908 #endif 909 ); 910 fprintf(stderr, 911 "usage: sshd [-46DdeiqTt] [-C connection_spec] [-c host_cert_file]\n" 912 " [-E log_file] [-f config_file] [-g login_grace_time]\n" 913 " [-h host_key_file] [-o option] [-p port] [-u len]\n" 914 ); 915 exit(1); 916 } 917 918 static void 919 send_rexec_state(int fd, struct sshbuf *conf) 920 { 921 struct sshbuf *m; 922 int r; 923 924 debug3("%s: entering fd = %d config len %zu", __func__, fd, 925 sshbuf_len(conf)); 926 927 /* 928 * Protocol from reexec master to child: 929 * string configuration 930 * string rngseed (only if OpenSSL is not self-seeded) 931 */ 932 if ((m = sshbuf_new()) == NULL) 933 fatal("%s: sshbuf_new failed", __func__); 934 if ((r = sshbuf_put_stringb(m, conf)) != 0) 935 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 936 937 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 938 rexec_send_rng_seed(m); 939 #endif 940 941 if (ssh_msg_send(fd, 0, m) == -1) 942 fatal("%s: ssh_msg_send failed", __func__); 943 944 sshbuf_free(m); 945 946 debug3("%s: done", __func__); 947 } 948 949 static void 950 recv_rexec_state(int fd, Buffer *conf) 951 { 952 Buffer m; 953 char *cp; 954 u_int len; 955 956 debug3("%s: entering fd = %d", __func__, fd); 957 958 buffer_init(&m); 959 960 if (ssh_msg_recv(fd, &m) == -1) 961 fatal("%s: ssh_msg_recv failed", __func__); 962 if (buffer_get_char(&m) != 0) 963 fatal("%s: rexec version mismatch", __func__); 964 965 cp = buffer_get_string(&m, &len); 966 if (conf != NULL) 967 buffer_append(conf, cp, len); 968 free(cp); 969 970 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY) 971 rexec_recv_rng_seed(&m); 972 #endif 973 974 buffer_free(&m); 975 976 debug3("%s: done", __func__); 977 } 978 979 /* Accept a connection from inetd */ 980 static void 981 server_accept_inetd(int *sock_in, int *sock_out) 982 { 983 int fd; 984 985 startup_pipe = -1; 986 if (rexeced_flag) { 987 close(REEXEC_CONFIG_PASS_FD); 988 *sock_in = *sock_out = dup(STDIN_FILENO); 989 if (!debug_flag) { 990 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); 991 close(REEXEC_STARTUP_PIPE_FD); 992 } 993 } else { 994 *sock_in = dup(STDIN_FILENO); 995 *sock_out = dup(STDOUT_FILENO); 996 } 997 /* 998 * We intentionally do not close the descriptors 0, 1, and 2 999 * as our code for setting the descriptors won't work if 1000 * ttyfd happens to be one of those. 1001 */ 1002 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1003 dup2(fd, STDIN_FILENO); 1004 dup2(fd, STDOUT_FILENO); 1005 if (!log_stderr) 1006 dup2(fd, STDERR_FILENO); 1007 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO)) 1008 close(fd); 1009 } 1010 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out); 1011 } 1012 1013 /* 1014 * Listen for TCP connections 1015 */ 1016 static void 1017 server_listen(void) 1018 { 1019 int ret, listen_sock, on = 1; 1020 struct addrinfo *ai; 1021 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 1022 1023 for (ai = options.listen_addrs; ai; ai = ai->ai_next) { 1024 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 1025 continue; 1026 if (num_listen_socks >= MAX_LISTEN_SOCKS) 1027 fatal("Too many listen sockets. " 1028 "Enlarge MAX_LISTEN_SOCKS"); 1029 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, 1030 ntop, sizeof(ntop), strport, sizeof(strport), 1031 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { 1032 error("getnameinfo failed: %.100s", 1033 ssh_gai_strerror(ret)); 1034 continue; 1035 } 1036 /* Create socket for listening. */ 1037 listen_sock = socket(ai->ai_family, ai->ai_socktype, 1038 ai->ai_protocol); 1039 if (listen_sock < 0) { 1040 /* kernel may not support ipv6 */ 1041 verbose("socket: %.100s", strerror(errno)); 1042 continue; 1043 } 1044 if (set_nonblock(listen_sock) == -1) { 1045 close(listen_sock); 1046 continue; 1047 } 1048 if (fcntl(listen_sock, F_SETFD, FD_CLOEXEC) == -1) { 1049 verbose("socket: CLOEXEC: %s", strerror(errno)); 1050 close(listen_sock); 1051 continue; 1052 } 1053 /* 1054 * Set socket options. 1055 * Allow local port reuse in TIME_WAIT. 1056 */ 1057 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, 1058 &on, sizeof(on)) == -1) 1059 error("setsockopt SO_REUSEADDR: %s", strerror(errno)); 1060 1061 /* Only communicate in IPv6 over AF_INET6 sockets. */ 1062 if (ai->ai_family == AF_INET6) 1063 sock_set_v6only(listen_sock); 1064 1065 debug("Bind to port %s on %s.", strport, ntop); 1066 1067 /* Bind the socket to the desired port. */ 1068 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1069 error("Bind to port %s on %s failed: %.200s.", 1070 strport, ntop, strerror(errno)); 1071 close(listen_sock); 1072 continue; 1073 } 1074 listen_socks[num_listen_socks] = listen_sock; 1075 num_listen_socks++; 1076 1077 /* Start listening on the port. */ 1078 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) 1079 fatal("listen on [%s]:%s: %.100s", 1080 ntop, strport, strerror(errno)); 1081 logit("Server listening on %s port %s.", ntop, strport); 1082 } 1083 freeaddrinfo(options.listen_addrs); 1084 1085 if (!num_listen_socks) 1086 fatal("Cannot bind any address."); 1087 } 1088 1089 /* 1090 * The main TCP accept loop. Note that, for the non-debug case, returns 1091 * from this function are in a forked subprocess. 1092 */ 1093 static void 1094 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s) 1095 { 1096 fd_set *fdset; 1097 int i, j, ret, maxfd; 1098 int startups = 0; 1099 int startup_p[2] = { -1 , -1 }; 1100 struct sockaddr_storage from; 1101 socklen_t fromlen; 1102 pid_t pid; 1103 u_char rnd[256]; 1104 1105 /* setup fd set for accept */ 1106 fdset = NULL; 1107 maxfd = 0; 1108 for (i = 0; i < num_listen_socks; i++) 1109 if (listen_socks[i] > maxfd) 1110 maxfd = listen_socks[i]; 1111 /* pipes connected to unauthenticated childs */ 1112 startup_pipes = xcalloc(options.max_startups, sizeof(int)); 1113 for (i = 0; i < options.max_startups; i++) 1114 startup_pipes[i] = -1; 1115 1116 /* 1117 * Stay listening for connections until the system crashes or 1118 * the daemon is killed with a signal. 1119 */ 1120 for (;;) { 1121 if (received_sighup) 1122 sighup_restart(); 1123 free(fdset); 1124 fdset = xcalloc(howmany(maxfd + 1, NFDBITS), 1125 sizeof(fd_mask)); 1126 1127 for (i = 0; i < num_listen_socks; i++) 1128 FD_SET(listen_socks[i], fdset); 1129 for (i = 0; i < options.max_startups; i++) 1130 if (startup_pipes[i] != -1) 1131 FD_SET(startup_pipes[i], fdset); 1132 1133 /* Wait in select until there is a connection. */ 1134 ret = select(maxfd+1, fdset, NULL, NULL, NULL); 1135 if (ret < 0 && errno != EINTR) 1136 error("select: %.100s", strerror(errno)); 1137 if (received_sigterm) { 1138 logit("Received signal %d; terminating.", 1139 (int) received_sigterm); 1140 close_listen_socks(); 1141 if (options.pid_file != NULL) 1142 unlink(options.pid_file); 1143 exit(received_sigterm == SIGTERM ? 0 : 255); 1144 } 1145 if (ret < 0) 1146 continue; 1147 1148 for (i = 0; i < options.max_startups; i++) 1149 if (startup_pipes[i] != -1 && 1150 FD_ISSET(startup_pipes[i], fdset)) { 1151 /* 1152 * the read end of the pipe is ready 1153 * if the child has closed the pipe 1154 * after successful authentication 1155 * or if the child has died 1156 */ 1157 close(startup_pipes[i]); 1158 startup_pipes[i] = -1; 1159 startups--; 1160 } 1161 for (i = 0; i < num_listen_socks; i++) { 1162 if (!FD_ISSET(listen_socks[i], fdset)) 1163 continue; 1164 fromlen = sizeof(from); 1165 *newsock = accept(listen_socks[i], 1166 (struct sockaddr *)&from, &fromlen); 1167 if (*newsock < 0) { 1168 if (errno != EINTR && errno != EWOULDBLOCK && 1169 errno != ECONNABORTED && errno != EAGAIN) 1170 error("accept: %.100s", 1171 strerror(errno)); 1172 if (errno == EMFILE || errno == ENFILE) 1173 usleep(100 * 1000); 1174 continue; 1175 } 1176 if (unset_nonblock(*newsock) == -1) { 1177 close(*newsock); 1178 continue; 1179 } 1180 if (drop_connection(startups) == 1) { 1181 char *laddr = get_local_ipaddr(*newsock); 1182 char *raddr = get_peer_ipaddr(*newsock); 1183 1184 verbose("drop connection #%d from [%s]:%d " 1185 "on [%s]:%d past MaxStartups", startups, 1186 raddr, get_peer_port(*newsock), 1187 laddr, get_local_port(*newsock)); 1188 free(laddr); 1189 free(raddr); 1190 close(*newsock); 1191 continue; 1192 } 1193 if (pipe(startup_p) == -1) { 1194 close(*newsock); 1195 continue; 1196 } 1197 1198 if (rexec_flag && socketpair(AF_UNIX, 1199 SOCK_STREAM, 0, config_s) == -1) { 1200 error("reexec socketpair: %s", 1201 strerror(errno)); 1202 close(*newsock); 1203 close(startup_p[0]); 1204 close(startup_p[1]); 1205 continue; 1206 } 1207 1208 for (j = 0; j < options.max_startups; j++) 1209 if (startup_pipes[j] == -1) { 1210 startup_pipes[j] = startup_p[0]; 1211 if (maxfd < startup_p[0]) 1212 maxfd = startup_p[0]; 1213 startups++; 1214 break; 1215 } 1216 1217 /* 1218 * Got connection. Fork a child to handle it, unless 1219 * we are in debugging mode. 1220 */ 1221 if (debug_flag) { 1222 /* 1223 * In debugging mode. Close the listening 1224 * socket, and start processing the 1225 * connection without forking. 1226 */ 1227 debug("Server will not fork when running in debugging mode."); 1228 close_listen_socks(); 1229 *sock_in = *newsock; 1230 *sock_out = *newsock; 1231 close(startup_p[0]); 1232 close(startup_p[1]); 1233 startup_pipe = -1; 1234 pid = getpid(); 1235 if (rexec_flag) { 1236 send_rexec_state(config_s[0], 1237 &cfg); 1238 close(config_s[0]); 1239 } 1240 break; 1241 } 1242 1243 /* 1244 * Normal production daemon. Fork, and have 1245 * the child process the connection. The 1246 * parent continues listening. 1247 */ 1248 platform_pre_fork(); 1249 if ((pid = fork()) == 0) { 1250 /* 1251 * Child. Close the listening and 1252 * max_startup sockets. Start using 1253 * the accepted socket. Reinitialize 1254 * logging (since our pid has changed). 1255 * We break out of the loop to handle 1256 * the connection. 1257 */ 1258 platform_post_fork_child(); 1259 startup_pipe = startup_p[1]; 1260 close_startup_pipes(); 1261 close_listen_socks(); 1262 *sock_in = *newsock; 1263 *sock_out = *newsock; 1264 log_init(__progname, 1265 options.log_level, 1266 options.log_facility, 1267 log_stderr); 1268 if (rexec_flag) 1269 close(config_s[0]); 1270 break; 1271 } 1272 1273 /* Parent. Stay in the loop. */ 1274 platform_post_fork_parent(pid); 1275 if (pid < 0) 1276 error("fork: %.100s", strerror(errno)); 1277 else 1278 debug("Forked child %ld.", (long)pid); 1279 1280 close(startup_p[1]); 1281 1282 if (rexec_flag) { 1283 send_rexec_state(config_s[0], &cfg); 1284 close(config_s[0]); 1285 close(config_s[1]); 1286 } 1287 close(*newsock); 1288 1289 /* 1290 * Ensure that our random state differs 1291 * from that of the child 1292 */ 1293 arc4random_stir(); 1294 arc4random_buf(rnd, sizeof(rnd)); 1295 #ifdef WITH_OPENSSL 1296 RAND_seed(rnd, sizeof(rnd)); 1297 if ((RAND_bytes((u_char *)rnd, 1)) != 1) 1298 fatal("%s: RAND_bytes failed", __func__); 1299 #endif 1300 explicit_bzero(rnd, sizeof(rnd)); 1301 } 1302 1303 /* child process check (or debug mode) */ 1304 if (num_listen_socks < 0) 1305 break; 1306 } 1307 } 1308 1309 /* 1310 * If IP options are supported, make sure there are none (log and 1311 * return an error if any are found). Basically we are worried about 1312 * source routing; it can be used to pretend you are somebody 1313 * (ip-address) you are not. That itself may be "almost acceptable" 1314 * under certain circumstances, but rhosts autentication is useless 1315 * if source routing is accepted. Notice also that if we just dropped 1316 * source routing here, the other side could use IP spoofing to do 1317 * rest of the interaction and could still bypass security. So we 1318 * exit here if we detect any IP options. 1319 */ 1320 static void 1321 check_ip_options(struct ssh *ssh) 1322 { 1323 #ifdef IP_OPTIONS 1324 int sock_in = ssh_packet_get_connection_in(ssh); 1325 struct sockaddr_storage from; 1326 u_char opts[200]; 1327 socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from); 1328 char text[sizeof(opts) * 3 + 1]; 1329 1330 memset(&from, 0, sizeof(from)); 1331 if (getpeername(sock_in, (struct sockaddr *)&from, 1332 &fromlen) < 0) 1333 return; 1334 if (from.ss_family != AF_INET) 1335 return; 1336 /* XXX IPv6 options? */ 1337 1338 if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts, 1339 &option_size) >= 0 && option_size != 0) { 1340 text[0] = '\0'; 1341 for (i = 0; i < option_size; i++) 1342 snprintf(text + i*3, sizeof(text) - i*3, 1343 " %2.2x", opts[i]); 1344 fatal("Connection from %.100s port %d with IP opts: %.800s", 1345 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text); 1346 } 1347 return; 1348 #endif /* IP_OPTIONS */ 1349 } 1350 1351 /* 1352 * Main program for the daemon. 1353 */ 1354 int 1355 main(int ac, char **av) 1356 { 1357 struct ssh *ssh = NULL; 1358 extern char *optarg; 1359 extern int optind; 1360 int r, opt, i, j, on = 1, already_daemon; 1361 int sock_in = -1, sock_out = -1, newsock = -1; 1362 const char *remote_ip; 1363 int remote_port; 1364 char *fp, *line, *laddr, *logfile = NULL; 1365 int config_s[2] = { -1 , -1 }; 1366 u_int n; 1367 u_int64_t ibytes, obytes; 1368 mode_t new_umask; 1369 struct sshkey *key; 1370 struct sshkey *pubkey; 1371 int keytype; 1372 Authctxt *authctxt; 1373 struct connection_info *connection_info = get_connection_info(0, 0); 1374 1375 ssh_malloc_init(); /* must be called before any mallocs */ 1376 1377 #ifdef HAVE_SECUREWARE 1378 (void)set_auth_parameters(ac, av); 1379 #endif 1380 __progname = ssh_get_progname(av[0]); 1381 1382 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ 1383 saved_argc = ac; 1384 rexec_argc = ac; 1385 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv)); 1386 for (i = 0; i < ac; i++) 1387 saved_argv[i] = xstrdup(av[i]); 1388 saved_argv[i] = NULL; 1389 1390 #ifndef HAVE_SETPROCTITLE 1391 /* Prepare for later setproctitle emulation */ 1392 compat_init_setproctitle(ac, av); 1393 av = saved_argv; 1394 #endif 1395 1396 if (geteuid() == 0 && setgroups(0, NULL) == -1) 1397 debug("setgroups(): %.200s", strerror(errno)); 1398 1399 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 1400 sanitise_stdfd(); 1401 1402 /* Initialize configuration options to their default values. */ 1403 initialize_server_options(&options); 1404 1405 /* Parse command-line arguments. */ 1406 while ((opt = getopt(ac, av, 1407 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) { 1408 switch (opt) { 1409 case '4': 1410 options.address_family = AF_INET; 1411 break; 1412 case '6': 1413 options.address_family = AF_INET6; 1414 break; 1415 case 'f': 1416 config_file_name = optarg; 1417 break; 1418 case 'c': 1419 if (options.num_host_cert_files >= MAX_HOSTCERTS) { 1420 fprintf(stderr, "too many host certificates.\n"); 1421 exit(1); 1422 } 1423 options.host_cert_files[options.num_host_cert_files++] = 1424 derelativise_path(optarg); 1425 break; 1426 case 'd': 1427 if (debug_flag == 0) { 1428 debug_flag = 1; 1429 options.log_level = SYSLOG_LEVEL_DEBUG1; 1430 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) 1431 options.log_level++; 1432 break; 1433 case 'D': 1434 no_daemon_flag = 1; 1435 break; 1436 case 'E': 1437 logfile = optarg; 1438 /* FALLTHROUGH */ 1439 case 'e': 1440 log_stderr = 1; 1441 break; 1442 case 'i': 1443 inetd_flag = 1; 1444 break; 1445 case 'r': 1446 rexec_flag = 0; 1447 break; 1448 case 'R': 1449 rexeced_flag = 1; 1450 inetd_flag = 1; 1451 break; 1452 case 'Q': 1453 /* ignored */ 1454 break; 1455 case 'q': 1456 options.log_level = SYSLOG_LEVEL_QUIET; 1457 break; 1458 case 'b': 1459 /* protocol 1, ignored */ 1460 break; 1461 case 'p': 1462 options.ports_from_cmdline = 1; 1463 if (options.num_ports >= MAX_PORTS) { 1464 fprintf(stderr, "too many ports.\n"); 1465 exit(1); 1466 } 1467 options.ports[options.num_ports++] = a2port(optarg); 1468 if (options.ports[options.num_ports-1] <= 0) { 1469 fprintf(stderr, "Bad port number.\n"); 1470 exit(1); 1471 } 1472 break; 1473 case 'g': 1474 if ((options.login_grace_time = convtime(optarg)) == -1) { 1475 fprintf(stderr, "Invalid login grace time.\n"); 1476 exit(1); 1477 } 1478 break; 1479 case 'k': 1480 /* protocol 1, ignored */ 1481 break; 1482 case 'h': 1483 if (options.num_host_key_files >= MAX_HOSTKEYS) { 1484 fprintf(stderr, "too many host keys.\n"); 1485 exit(1); 1486 } 1487 options.host_key_files[options.num_host_key_files++] = 1488 derelativise_path(optarg); 1489 break; 1490 case 't': 1491 test_flag = 1; 1492 break; 1493 case 'T': 1494 test_flag = 2; 1495 break; 1496 case 'C': 1497 if (parse_server_match_testspec(connection_info, 1498 optarg) == -1) 1499 exit(1); 1500 break; 1501 case 'u': 1502 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL); 1503 if (utmp_len > HOST_NAME_MAX+1) { 1504 fprintf(stderr, "Invalid utmp length.\n"); 1505 exit(1); 1506 } 1507 break; 1508 case 'o': 1509 line = xstrdup(optarg); 1510 if (process_server_config_line(&options, line, 1511 "command-line", 0, NULL, NULL) != 0) 1512 exit(1); 1513 free(line); 1514 break; 1515 case '?': 1516 default: 1517 usage(); 1518 break; 1519 } 1520 } 1521 if (rexeced_flag || inetd_flag) 1522 rexec_flag = 0; 1523 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/'))) 1524 fatal("sshd re-exec requires execution with an absolute path"); 1525 if (rexeced_flag) 1526 closefrom(REEXEC_MIN_FREE_FD); 1527 else 1528 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); 1529 1530 #ifdef WITH_OPENSSL 1531 OpenSSL_add_all_algorithms(); 1532 #endif 1533 1534 /* If requested, redirect the logs to the specified logfile. */ 1535 if (logfile != NULL) 1536 log_redirect_stderr_to(logfile); 1537 /* 1538 * Force logging to stderr until we have loaded the private host 1539 * key (unless started from inetd) 1540 */ 1541 log_init(__progname, 1542 options.log_level == SYSLOG_LEVEL_NOT_SET ? 1543 SYSLOG_LEVEL_INFO : options.log_level, 1544 options.log_facility == SYSLOG_FACILITY_NOT_SET ? 1545 SYSLOG_FACILITY_AUTH : options.log_facility, 1546 log_stderr || !inetd_flag); 1547 1548 /* 1549 * Unset KRB5CCNAME, otherwise the user's session may inherit it from 1550 * root's environment 1551 */ 1552 if (getenv("KRB5CCNAME") != NULL) 1553 (void) unsetenv("KRB5CCNAME"); 1554 1555 #ifdef _UNICOS 1556 /* Cray can define user privs drop all privs now! 1557 * Not needed on PRIV_SU systems! 1558 */ 1559 drop_cray_privs(); 1560 #endif 1561 1562 sensitive_data.have_ssh2_key = 0; 1563 1564 /* 1565 * If we're doing an extended config test, make sure we have all of 1566 * the parameters we need. If we're not doing an extended test, 1567 * do not silently ignore connection test params. 1568 */ 1569 if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0) 1570 fatal("user, host and addr are all required when testing " 1571 "Match configs"); 1572 if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0) 1573 fatal("Config test connection parameter (-C) provided without " 1574 "test mode (-T)"); 1575 1576 /* Fetch our configuration */ 1577 buffer_init(&cfg); 1578 if (rexeced_flag) 1579 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); 1580 else if (strcasecmp(config_file_name, "none") != 0) 1581 load_server_config(config_file_name, &cfg); 1582 1583 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name, 1584 &cfg, NULL); 1585 1586 seed_rng(); 1587 1588 /* Fill in default values for those options not explicitly set. */ 1589 fill_default_server_options(&options); 1590 1591 /* challenge-response is implemented via keyboard interactive */ 1592 if (options.challenge_response_authentication) 1593 options.kbd_interactive_authentication = 1; 1594 1595 /* Check that options are sensible */ 1596 if (options.authorized_keys_command_user == NULL && 1597 (options.authorized_keys_command != NULL && 1598 strcasecmp(options.authorized_keys_command, "none") != 0)) 1599 fatal("AuthorizedKeysCommand set without " 1600 "AuthorizedKeysCommandUser"); 1601 if (options.authorized_principals_command_user == NULL && 1602 (options.authorized_principals_command != NULL && 1603 strcasecmp(options.authorized_principals_command, "none") != 0)) 1604 fatal("AuthorizedPrincipalsCommand set without " 1605 "AuthorizedPrincipalsCommandUser"); 1606 1607 /* 1608 * Check whether there is any path through configured auth methods. 1609 * Unfortunately it is not possible to verify this generally before 1610 * daemonisation in the presence of Match block, but this catches 1611 * and warns for trivial misconfigurations that could break login. 1612 */ 1613 if (options.num_auth_methods != 0) { 1614 for (n = 0; n < options.num_auth_methods; n++) { 1615 if (auth2_methods_valid(options.auth_methods[n], 1616 1) == 0) 1617 break; 1618 } 1619 if (n >= options.num_auth_methods) 1620 fatal("AuthenticationMethods cannot be satisfied by " 1621 "enabled authentication methods"); 1622 } 1623 1624 /* Check that there are no remaining arguments. */ 1625 if (optind < ac) { 1626 fprintf(stderr, "Extra argument %s.\n", av[optind]); 1627 exit(1); 1628 } 1629 1630 debug("sshd version %s, %s", SSH_VERSION, 1631 #ifdef WITH_OPENSSL 1632 SSLeay_version(SSLEAY_VERSION) 1633 #else 1634 "without OpenSSL" 1635 #endif 1636 ); 1637 1638 /* Store privilege separation user for later use if required. */ 1639 privsep_chroot = use_privsep && (getuid() == 0 || geteuid() == 0); 1640 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) { 1641 if (privsep_chroot || options.kerberos_authentication) 1642 fatal("Privilege separation user %s does not exist", 1643 SSH_PRIVSEP_USER); 1644 } else { 1645 explicit_bzero(privsep_pw->pw_passwd, 1646 strlen(privsep_pw->pw_passwd)); 1647 privsep_pw = pwcopy(privsep_pw); 1648 free(privsep_pw->pw_passwd); 1649 privsep_pw->pw_passwd = xstrdup("*"); 1650 } 1651 endpwent(); 1652 1653 /* load host keys */ 1654 sensitive_data.host_keys = xcalloc(options.num_host_key_files, 1655 sizeof(struct sshkey *)); 1656 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files, 1657 sizeof(struct sshkey *)); 1658 1659 if (options.host_key_agent) { 1660 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME)) 1661 setenv(SSH_AUTHSOCKET_ENV_NAME, 1662 options.host_key_agent, 1); 1663 if ((r = ssh_get_authentication_socket(NULL)) == 0) 1664 have_agent = 1; 1665 else 1666 error("Could not connect to agent \"%s\": %s", 1667 options.host_key_agent, ssh_err(r)); 1668 } 1669 1670 for (i = 0; i < options.num_host_key_files; i++) { 1671 if (options.host_key_files[i] == NULL) 1672 continue; 1673 key = key_load_private(options.host_key_files[i], "", NULL); 1674 pubkey = key_load_public(options.host_key_files[i], NULL); 1675 1676 if (pubkey == NULL && key != NULL) 1677 pubkey = key_demote(key); 1678 sensitive_data.host_keys[i] = key; 1679 sensitive_data.host_pubkeys[i] = pubkey; 1680 1681 if (key == NULL && pubkey != NULL && have_agent) { 1682 debug("will rely on agent for hostkey %s", 1683 options.host_key_files[i]); 1684 keytype = pubkey->type; 1685 } else if (key != NULL) { 1686 keytype = key->type; 1687 } else { 1688 error("Could not load host key: %s", 1689 options.host_key_files[i]); 1690 sensitive_data.host_keys[i] = NULL; 1691 sensitive_data.host_pubkeys[i] = NULL; 1692 continue; 1693 } 1694 1695 switch (keytype) { 1696 case KEY_RSA: 1697 case KEY_DSA: 1698 case KEY_ECDSA: 1699 case KEY_ED25519: 1700 if (have_agent || key != NULL) 1701 sensitive_data.have_ssh2_key = 1; 1702 break; 1703 } 1704 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash, 1705 SSH_FP_DEFAULT)) == NULL) 1706 fatal("sshkey_fingerprint failed"); 1707 debug("%s host key #%d: %s %s", 1708 key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp); 1709 free(fp); 1710 } 1711 if (!sensitive_data.have_ssh2_key) { 1712 logit("sshd: no hostkeys available -- exiting."); 1713 exit(1); 1714 } 1715 1716 /* 1717 * Load certificates. They are stored in an array at identical 1718 * indices to the public keys that they relate to. 1719 */ 1720 sensitive_data.host_certificates = xcalloc(options.num_host_key_files, 1721 sizeof(struct sshkey *)); 1722 for (i = 0; i < options.num_host_key_files; i++) 1723 sensitive_data.host_certificates[i] = NULL; 1724 1725 for (i = 0; i < options.num_host_cert_files; i++) { 1726 if (options.host_cert_files[i] == NULL) 1727 continue; 1728 key = key_load_public(options.host_cert_files[i], NULL); 1729 if (key == NULL) { 1730 error("Could not load host certificate: %s", 1731 options.host_cert_files[i]); 1732 continue; 1733 } 1734 if (!key_is_cert(key)) { 1735 error("Certificate file is not a certificate: %s", 1736 options.host_cert_files[i]); 1737 key_free(key); 1738 continue; 1739 } 1740 /* Find matching private key */ 1741 for (j = 0; j < options.num_host_key_files; j++) { 1742 if (key_equal_public(key, 1743 sensitive_data.host_keys[j])) { 1744 sensitive_data.host_certificates[j] = key; 1745 break; 1746 } 1747 } 1748 if (j >= options.num_host_key_files) { 1749 error("No matching private key for certificate: %s", 1750 options.host_cert_files[i]); 1751 key_free(key); 1752 continue; 1753 } 1754 sensitive_data.host_certificates[j] = key; 1755 debug("host certificate: #%d type %d %s", j, key->type, 1756 key_type(key)); 1757 } 1758 1759 if (privsep_chroot) { 1760 struct stat st; 1761 1762 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || 1763 (S_ISDIR(st.st_mode) == 0)) 1764 fatal("Missing privilege separation directory: %s", 1765 _PATH_PRIVSEP_CHROOT_DIR); 1766 1767 #ifdef HAVE_CYGWIN 1768 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && 1769 (st.st_uid != getuid () || 1770 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) 1771 #else 1772 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) 1773 #endif 1774 fatal("%s must be owned by root and not group or " 1775 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); 1776 } 1777 1778 if (test_flag > 1) { 1779 if (server_match_spec_complete(connection_info) == 1) 1780 parse_server_match_config(&options, connection_info); 1781 dump_config(&options); 1782 } 1783 1784 /* Configuration looks good, so exit if in test mode. */ 1785 if (test_flag) 1786 exit(0); 1787 1788 /* 1789 * Clear out any supplemental groups we may have inherited. This 1790 * prevents inadvertent creation of files with bad modes (in the 1791 * portable version at least, it's certainly possible for PAM 1792 * to create a file, and we can't control the code in every 1793 * module which might be used). 1794 */ 1795 if (setgroups(0, NULL) < 0) 1796 debug("setgroups() failed: %.200s", strerror(errno)); 1797 1798 if (rexec_flag) { 1799 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); 1800 for (i = 0; i < rexec_argc; i++) { 1801 debug("rexec_argv[%d]='%s'", i, saved_argv[i]); 1802 rexec_argv[i] = saved_argv[i]; 1803 } 1804 rexec_argv[rexec_argc] = "-R"; 1805 rexec_argv[rexec_argc + 1] = NULL; 1806 } 1807 1808 /* Ensure that umask disallows at least group and world write */ 1809 new_umask = umask(0077) | 0022; 1810 (void) umask(new_umask); 1811 1812 /* Initialize the log (it is reinitialized below in case we forked). */ 1813 if (debug_flag && (!inetd_flag || rexeced_flag)) 1814 log_stderr = 1; 1815 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1816 1817 /* 1818 * If not in debugging mode, not started from inetd and not already 1819 * daemonized (eg re-exec via SIGHUP), disconnect from the controlling 1820 * terminal, and fork. The original process exits. 1821 */ 1822 already_daemon = daemonized(); 1823 if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) { 1824 1825 if (daemon(0, 0) < 0) 1826 fatal("daemon() failed: %.200s", strerror(errno)); 1827 1828 disconnect_controlling_tty(); 1829 } 1830 /* Reinitialize the log (because of the fork above). */ 1831 log_init(__progname, options.log_level, options.log_facility, log_stderr); 1832 1833 /* Chdir to the root directory so that the current disk can be 1834 unmounted if desired. */ 1835 if (chdir("/") == -1) 1836 error("chdir(\"/\"): %s", strerror(errno)); 1837 1838 /* ignore SIGPIPE */ 1839 signal(SIGPIPE, SIG_IGN); 1840 1841 /* Get a connection, either from inetd or a listening TCP socket */ 1842 if (inetd_flag) { 1843 server_accept_inetd(&sock_in, &sock_out); 1844 } else { 1845 platform_pre_listen(); 1846 server_listen(); 1847 1848 signal(SIGHUP, sighup_handler); 1849 signal(SIGCHLD, main_sigchld_handler); 1850 signal(SIGTERM, sigterm_handler); 1851 signal(SIGQUIT, sigterm_handler); 1852 1853 /* 1854 * Write out the pid file after the sigterm handler 1855 * is setup and the listen sockets are bound 1856 */ 1857 if (options.pid_file != NULL && !debug_flag) { 1858 FILE *f = fopen(options.pid_file, "w"); 1859 1860 if (f == NULL) { 1861 error("Couldn't create pid file \"%s\": %s", 1862 options.pid_file, strerror(errno)); 1863 } else { 1864 fprintf(f, "%ld\n", (long) getpid()); 1865 fclose(f); 1866 } 1867 } 1868 1869 /* Accept a connection and return in a forked child */ 1870 server_accept_loop(&sock_in, &sock_out, 1871 &newsock, config_s); 1872 } 1873 1874 /* This is the child processing a new connection. */ 1875 setproctitle("%s", "[accepted]"); 1876 1877 /* 1878 * Create a new session and process group since the 4.4BSD 1879 * setlogin() affects the entire process group. We don't 1880 * want the child to be able to affect the parent. 1881 */ 1882 #if !defined(SSHD_ACQUIRES_CTTY) 1883 /* 1884 * If setsid is called, on some platforms sshd will later acquire a 1885 * controlling terminal which will result in "could not set 1886 * controlling tty" errors. 1887 */ 1888 if (!debug_flag && !inetd_flag && setsid() < 0) 1889 error("setsid: %.100s", strerror(errno)); 1890 #endif 1891 1892 if (rexec_flag) { 1893 int fd; 1894 1895 debug("rexec start in %d out %d newsock %d pipe %d sock %d", 1896 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 1897 dup2(newsock, STDIN_FILENO); 1898 dup2(STDIN_FILENO, STDOUT_FILENO); 1899 if (startup_pipe == -1) 1900 close(REEXEC_STARTUP_PIPE_FD); 1901 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) { 1902 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); 1903 close(startup_pipe); 1904 startup_pipe = REEXEC_STARTUP_PIPE_FD; 1905 } 1906 1907 dup2(config_s[1], REEXEC_CONFIG_PASS_FD); 1908 close(config_s[1]); 1909 1910 execv(rexec_argv[0], rexec_argv); 1911 1912 /* Reexec has failed, fall back and continue */ 1913 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); 1914 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); 1915 log_init(__progname, options.log_level, 1916 options.log_facility, log_stderr); 1917 1918 /* Clean up fds */ 1919 close(REEXEC_CONFIG_PASS_FD); 1920 newsock = sock_out = sock_in = dup(STDIN_FILENO); 1921 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { 1922 dup2(fd, STDIN_FILENO); 1923 dup2(fd, STDOUT_FILENO); 1924 if (fd > STDERR_FILENO) 1925 close(fd); 1926 } 1927 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", 1928 sock_in, sock_out, newsock, startup_pipe, config_s[0]); 1929 } 1930 1931 /* Executed child processes don't need these. */ 1932 fcntl(sock_out, F_SETFD, FD_CLOEXEC); 1933 fcntl(sock_in, F_SETFD, FD_CLOEXEC); 1934 1935 /* 1936 * Disable the key regeneration alarm. We will not regenerate the 1937 * key since we are no longer in a position to give it to anyone. We 1938 * will not restart on SIGHUP since it no longer makes sense. 1939 */ 1940 alarm(0); 1941 signal(SIGALRM, SIG_DFL); 1942 signal(SIGHUP, SIG_DFL); 1943 signal(SIGTERM, SIG_DFL); 1944 signal(SIGQUIT, SIG_DFL); 1945 signal(SIGCHLD, SIG_DFL); 1946 signal(SIGINT, SIG_DFL); 1947 1948 /* 1949 * Register our connection. This turns encryption off because we do 1950 * not have a key. 1951 */ 1952 packet_set_connection(sock_in, sock_out); 1953 packet_set_server(); 1954 ssh = active_state; /* XXX */ 1955 1956 check_ip_options(ssh); 1957 1958 /* Prepare the channels layer */ 1959 channel_init_channels(ssh); 1960 channel_set_af(ssh, options.address_family); 1961 process_permitopen(ssh, &options); 1962 1963 /* Set SO_KEEPALIVE if requested. */ 1964 if (options.tcp_keep_alive && packet_connection_is_on_socket() && 1965 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) 1966 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); 1967 1968 if ((remote_port = ssh_remote_port(ssh)) < 0) { 1969 debug("ssh_remote_port failed"); 1970 cleanup_exit(255); 1971 } 1972 1973 /* 1974 * The rest of the code depends on the fact that 1975 * ssh_remote_ipaddr() caches the remote ip, even if 1976 * the socket goes away. 1977 */ 1978 remote_ip = ssh_remote_ipaddr(ssh); 1979 1980 #ifdef SSH_AUDIT_EVENTS 1981 audit_connection_from(remote_ip, remote_port); 1982 #endif 1983 1984 /* Log the connection. */ 1985 laddr = get_local_ipaddr(sock_in); 1986 verbose("Connection from %s port %d on %s port %d", 1987 remote_ip, remote_port, laddr, ssh_local_port(ssh)); 1988 free(laddr); 1989 1990 /* 1991 * We don't want to listen forever unless the other side 1992 * successfully authenticates itself. So we set up an alarm which is 1993 * cleared after successful authentication. A limit of zero 1994 * indicates no limit. Note that we don't set the alarm in debugging 1995 * mode; it is just annoying to have the server exit just when you 1996 * are about to discover the bug. 1997 */ 1998 signal(SIGALRM, grace_alarm_handler); 1999 if (!debug_flag) 2000 alarm(options.login_grace_time); 2001 2002 sshd_exchange_identification(ssh, sock_in, sock_out); 2003 packet_set_nonblocking(); 2004 2005 /* allocate authentication context */ 2006 authctxt = xcalloc(1, sizeof(*authctxt)); 2007 2008 authctxt->loginmsg = &loginmsg; 2009 2010 /* XXX global for cleanup, access from other modules */ 2011 the_authctxt = authctxt; 2012 2013 /* prepare buffer to collect messages to display to user after login */ 2014 buffer_init(&loginmsg); 2015 auth_debug_reset(); 2016 2017 if (use_privsep) { 2018 if (privsep_preauth(authctxt) == 1) 2019 goto authenticated; 2020 } else if (have_agent) { 2021 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { 2022 error("Unable to get agent socket: %s", ssh_err(r)); 2023 have_agent = 0; 2024 } 2025 } 2026 2027 /* perform the key exchange */ 2028 /* authenticate user and start session */ 2029 do_ssh2_kex(); 2030 do_authentication2(authctxt); 2031 2032 /* 2033 * If we use privilege separation, the unprivileged child transfers 2034 * the current keystate and exits 2035 */ 2036 if (use_privsep) { 2037 mm_send_keystate(pmonitor); 2038 packet_clear_keys(); 2039 exit(0); 2040 } 2041 2042 authenticated: 2043 /* 2044 * Cancel the alarm we set to limit the time taken for 2045 * authentication. 2046 */ 2047 alarm(0); 2048 signal(SIGALRM, SIG_DFL); 2049 authctxt->authenticated = 1; 2050 if (startup_pipe != -1) { 2051 close(startup_pipe); 2052 startup_pipe = -1; 2053 } 2054 2055 #ifdef SSH_AUDIT_EVENTS 2056 audit_event(SSH_AUTH_SUCCESS); 2057 #endif 2058 2059 #ifdef GSSAPI 2060 if (options.gss_authentication) { 2061 temporarily_use_uid(authctxt->pw); 2062 ssh_gssapi_storecreds(); 2063 restore_uid(); 2064 } 2065 #endif 2066 #ifdef USE_PAM 2067 if (options.use_pam) { 2068 do_pam_setcred(1); 2069 do_pam_session(); 2070 } 2071 #endif 2072 2073 /* 2074 * In privilege separation, we fork another child and prepare 2075 * file descriptor passing. 2076 */ 2077 if (use_privsep) { 2078 privsep_postauth(authctxt); 2079 /* the monitor process [priv] will not return */ 2080 } 2081 2082 packet_set_timeout(options.client_alive_interval, 2083 options.client_alive_count_max); 2084 2085 /* Try to send all our hostkeys to the client */ 2086 notify_hostkeys(ssh); 2087 2088 /* Start session. */ 2089 do_authenticated(ssh, authctxt); 2090 2091 /* The connection has been terminated. */ 2092 packet_get_bytes(&ibytes, &obytes); 2093 verbose("Transferred: sent %llu, received %llu bytes", 2094 (unsigned long long)obytes, (unsigned long long)ibytes); 2095 2096 verbose("Closing connection to %.500s port %d", remote_ip, remote_port); 2097 2098 #ifdef USE_PAM 2099 if (options.use_pam) 2100 finish_pam(); 2101 #endif /* USE_PAM */ 2102 2103 #ifdef SSH_AUDIT_EVENTS 2104 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); 2105 #endif 2106 2107 packet_close(); 2108 2109 if (use_privsep) 2110 mm_terminate(); 2111 2112 exit(0); 2113 } 2114 2115 int 2116 sshd_hostkey_sign(struct sshkey *privkey, struct sshkey *pubkey, 2117 u_char **signature, size_t *slen, const u_char *data, size_t dlen, 2118 const char *alg, u_int flag) 2119 { 2120 int r; 2121 u_int xxx_slen, xxx_dlen = dlen; 2122 2123 if (privkey) { 2124 if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen, 2125 alg) < 0)) 2126 fatal("%s: key_sign failed", __func__); 2127 if (slen) 2128 *slen = xxx_slen; 2129 } else if (use_privsep) { 2130 if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen, 2131 alg) < 0) 2132 fatal("%s: pubkey_sign failed", __func__); 2133 if (slen) 2134 *slen = xxx_slen; 2135 } else { 2136 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen, 2137 data, dlen, alg, datafellows)) != 0) 2138 fatal("%s: ssh_agent_sign failed: %s", 2139 __func__, ssh_err(r)); 2140 } 2141 return 0; 2142 } 2143 2144 /* SSH2 key exchange */ 2145 static void 2146 do_ssh2_kex(void) 2147 { 2148 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER }; 2149 struct kex *kex; 2150 int r; 2151 2152 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 2153 options.kex_algorithms); 2154 myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal( 2155 options.ciphers); 2156 myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal( 2157 options.ciphers); 2158 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 2159 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 2160 2161 if (options.compression == COMP_NONE) { 2162 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 2163 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; 2164 } 2165 2166 if (options.rekey_limit || options.rekey_interval) 2167 packet_set_rekey_limits(options.rekey_limit, 2168 options.rekey_interval); 2169 2170 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal( 2171 list_hostkey_types()); 2172 2173 /* start key exchange */ 2174 if ((r = kex_setup(active_state, myproposal)) != 0) 2175 fatal("kex_setup: %s", ssh_err(r)); 2176 kex = active_state->kex; 2177 #ifdef WITH_OPENSSL 2178 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; 2179 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; 2180 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_server; 2181 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_server; 2182 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_server; 2183 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; 2184 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; 2185 # ifdef OPENSSL_HAS_ECC 2186 kex->kex[KEX_ECDH_SHA2] = kexecdh_server; 2187 # endif 2188 #endif 2189 kex->kex[KEX_C25519_SHA256] = kexc25519_server; 2190 kex->server = 1; 2191 kex->client_version_string=client_version_string; 2192 kex->server_version_string=server_version_string; 2193 kex->load_host_public_key=&get_hostkey_public_by_type; 2194 kex->load_host_private_key=&get_hostkey_private_by_type; 2195 kex->host_key_index=&get_hostkey_index; 2196 kex->sign = sshd_hostkey_sign; 2197 2198 ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done); 2199 2200 session_id2 = kex->session_id; 2201 session_id2_len = kex->session_id_len; 2202 2203 #ifdef DEBUG_KEXDH 2204 /* send 1st encrypted/maced/compressed message */ 2205 packet_start(SSH2_MSG_IGNORE); 2206 packet_put_cstring("markus"); 2207 packet_send(); 2208 packet_write_wait(); 2209 #endif 2210 debug("KEX done"); 2211 } 2212 2213 /* server specific fatal cleanup */ 2214 void 2215 cleanup_exit(int i) 2216 { 2217 struct ssh *ssh = active_state; /* XXX */ 2218 2219 if (the_authctxt) { 2220 do_cleanup(ssh, the_authctxt); 2221 if (use_privsep && privsep_is_preauth && 2222 pmonitor != NULL && pmonitor->m_pid > 1) { 2223 debug("Killing privsep child %d", pmonitor->m_pid); 2224 if (kill(pmonitor->m_pid, SIGKILL) != 0 && 2225 errno != ESRCH) 2226 error("%s: kill(%d): %s", __func__, 2227 pmonitor->m_pid, strerror(errno)); 2228 } 2229 } 2230 #ifdef SSH_AUDIT_EVENTS 2231 /* done after do_cleanup so it can cancel the PAM auth 'thread' */ 2232 if (!use_privsep || mm_is_monitor()) 2233 audit_event(SSH_CONNECTION_ABANDON); 2234 #endif 2235 _exit(i); 2236 } 2237