1 /* $OpenBSD: sshd.c,v 1.465 2016/02/15 09:47:49 dtucker Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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.
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".
18 * SSH2 implementation:
19 * Privilege Separation:
21 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
22 * Copyright (c) 2002 Niels Provos. All rights reserved.
24 * Redistribution and use in source and binary forms, with or without
25 * modification, are permitted provided that the following conditions
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.
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.
48 #include <sys/types.h>
49 #include <sys/ioctl.h>
51 #include <sys/socket.h>
52 #ifdef HAVE_SYS_STAT_H
53 # include <sys/stat.h>
55 #ifdef HAVE_SYS_TIME_H
56 # include <sys/time.h>
58 #include "openbsd-compat/sys-tree.h"
59 #include "openbsd-compat/sys-queue.h"
79 #include <openssl/dh.h>
80 #include <openssl/bn.h>
81 #include <openssl/rand.h>
82 #include "openbsd-compat/openssl-compat.h"
85 #ifdef HAVE_SECUREWARE
86 #include <sys/security.h>
92 #if defined(GSSAPI) && defined(HAVE_GSSAPI_GSSAPI_H)
93 #include <gssapi/gssapi.h>
94 #elif defined(GSSAPI) && defined(HAVE_GSSAPI_H)
110 #include "servconf.h"
117 #include "myproposal.h"
118 #include "authfile.h"
119 #include "pathnames.h"
120 #include "atomicio.h"
121 #include "canohost.h"
122 #include "hostfile.h"
126 #include "dispatch.h"
127 #include "channels.h"
129 #include "monitor_mm.h"
134 #include "monitor_wrap.h"
135 #include "ssh-sandbox.h"
151 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
152 #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
153 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
154 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
156 extern char *__progname;
158 /* Server configuration options. */
159 ServerOptions options;
161 /* Name of the server configuration file. */
162 char *config_file_name = _PATH_SERVER_CONFIG_FILE;
165 * Debug mode flag. This can be set on the command line. If debug
166 * mode is enabled, extra debugging output will be sent to the system
167 * log, the daemon will not go to background, and will exit after processing
168 * the first connection.
172 /* Flag indicating that the daemon should only test the configuration and keys. */
175 /* Flag indicating that the daemon is being started from inetd. */
178 /* Flag indicating that sshd should not detach and become a daemon. */
179 int no_daemon_flag = 0;
181 /* debug goes to stderr unless inetd_flag is set */
184 /* Saved arguments to main(). */
189 int rexeced_flag = 0;
195 * The sockets that the server is listening; this is used in the SIGHUP
198 #define MAX_LISTEN_SOCKS 16
199 int listen_socks[MAX_LISTEN_SOCKS];
200 int num_listen_socks = 0;
203 * the client's version string, passed by sshd2 in compat mode. if != NULL,
204 * sshd will skip the version-number exchange
206 char *client_version_string = NULL;
207 char *server_version_string = NULL;
209 /* Daemon's agent connection */
214 * Any really sensitive data in the application is contained in this
215 * structure. The idea is that this structure could be locked into memory so
216 * that the pages do not get written into swap. However, there are some
217 * problems. The private key contains BIGNUMs, and we do not (in principle)
218 * have access to the internals of them, and locking just the structure is
219 * not very useful. Currently, memory locking is not implemented.
222 Key *server_key; /* ephemeral server key */
223 Key *ssh1_host_key; /* ssh1 host key */
224 Key **host_keys; /* all private host keys */
225 Key **host_pubkeys; /* all public host keys */
226 Key **host_certificates; /* all public host certificates */
229 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
233 * Flag indicating whether the RSA server key needs to be regenerated.
234 * Is set in the SIGALRM handler and cleared when the key is regenerated.
236 static volatile sig_atomic_t key_do_regen = 0;
238 /* This is set to true when a signal is received. */
239 static volatile sig_atomic_t received_sighup = 0;
240 static volatile sig_atomic_t received_sigterm = 0;
242 /* session identifier, used by RSA-auth */
243 u_char session_id[16];
246 u_char *session_id2 = NULL;
247 u_int session_id2_len = 0;
249 /* record remote hostname or ip */
250 u_int utmp_len = HOST_NAME_MAX+1;
252 /* options.max_startup sized array of fd ints */
253 int *startup_pipes = NULL;
254 int startup_pipe; /* in child */
256 /* variables used for privilege separation */
257 int use_privsep = -1;
258 struct monitor *pmonitor = NULL;
259 int privsep_is_preauth = 1;
261 /* global authentication context */
262 Authctxt *the_authctxt = NULL;
264 /* sshd_config buffer */
267 /* message to be displayed after login */
270 /* Unprivileged user */
271 struct passwd *privsep_pw = NULL;
273 /* Prototypes for various functions defined later in this file. */
274 void destroy_sensitive_data(void);
275 void demote_sensitive_data(void);
278 static void do_ssh1_kex(void);
280 static void do_ssh2_kex(void);
283 * Close all listening sockets
286 close_listen_socks(void)
290 for (i = 0; i < num_listen_socks; i++)
291 close(listen_socks[i]);
292 num_listen_socks = -1;
296 close_startup_pipes(void)
301 for (i = 0; i < options.max_startups; i++)
302 if (startup_pipes[i] != -1)
303 close(startup_pipes[i]);
307 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
308 * the effect is to reread the configuration file (and to regenerate
314 sighup_handler(int sig)
316 int save_errno = errno;
319 signal(SIGHUP, sighup_handler);
324 * Called from the main program after receiving SIGHUP.
325 * Restarts the server.
330 logit("Received SIGHUP; restarting.");
331 platform_pre_restart();
332 close_listen_socks();
333 close_startup_pipes();
334 alarm(0); /* alarm timer persists across exec */
335 signal(SIGHUP, SIG_IGN); /* will be restored after exec */
336 execv(saved_argv[0], saved_argv);
337 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
343 * Generic signal handler for terminating signals in the master daemon.
347 sigterm_handler(int sig)
349 received_sigterm = sig;
353 * SIGCHLD handler. This is called whenever a child dies. This will then
354 * reap any zombies left by exited children.
358 main_sigchld_handler(int sig)
360 int save_errno = errno;
364 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
365 (pid < 0 && errno == EINTR))
368 signal(SIGCHLD, main_sigchld_handler);
373 * Signal handler for the alarm after the login grace period has expired.
377 grace_alarm_handler(int sig)
379 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
380 kill(pmonitor->m_pid, SIGALRM);
383 * Try to kill any processes that we have spawned, E.g. authorized
384 * keys command helpers.
386 if (getpgid(0) == getpid()) {
387 signal(SIGTERM, SIG_IGN);
391 /* Log error and exit. */
392 sigdie("Timeout before authentication for %s", get_remote_ipaddr());
396 * Signal handler for the key regeneration alarm. Note that this
397 * alarm only occurs in the daemon waiting for connections, and it does not
398 * do anything with the private key or random state before forking.
399 * Thus there should be no concurrency control/asynchronous execution
403 generate_ephemeral_server_key(void)
405 verbose("Generating %s%d bit RSA key.",
406 sensitive_data.server_key ? "new " : "", options.server_key_bits);
407 if (sensitive_data.server_key != NULL)
408 key_free(sensitive_data.server_key);
409 sensitive_data.server_key = key_generate(KEY_RSA1,
410 options.server_key_bits);
411 verbose("RSA key generation complete.");
413 arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
418 key_regeneration_alarm(int sig)
420 int save_errno = errno;
422 signal(SIGALRM, SIG_DFL);
428 sshd_exchange_identification(int sock_in, int sock_out)
432 int remote_major, remote_minor;
434 char *s, *newline = "\n";
435 char buf[256]; /* Must not be larger than remote_version. */
436 char remote_version[256]; /* Must be at least as big as buf. */
438 if ((options.protocol & SSH_PROTO_1) &&
439 (options.protocol & SSH_PROTO_2)) {
440 major = PROTOCOL_MAJOR_1;
442 } else if (options.protocol & SSH_PROTO_2) {
443 major = PROTOCOL_MAJOR_2;
444 minor = PROTOCOL_MINOR_2;
447 major = PROTOCOL_MAJOR_1;
448 minor = PROTOCOL_MINOR_1;
451 xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s",
452 major, minor, SSH_VERSION,
453 *options.version_addendum == '\0' ? "" : " ",
454 options.version_addendum, newline);
456 /* Send our protocol version identification. */
457 if (atomicio(vwrite, sock_out, server_version_string,
458 strlen(server_version_string))
459 != strlen(server_version_string)) {
460 logit("Could not write ident string to %s", get_remote_ipaddr());
464 /* Read other sides version identification. */
465 memset(buf, 0, sizeof(buf));
466 for (i = 0; i < sizeof(buf) - 1; i++) {
467 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
468 logit("Did not receive identification string from %s",
469 get_remote_ipaddr());
472 if (buf[i] == '\r') {
474 /* Kludge for F-Secure Macintosh < 1.0.2 */
476 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
480 if (buf[i] == '\n') {
485 buf[sizeof(buf) - 1] = 0;
486 client_version_string = xstrdup(buf);
489 * Check that the versions match. In future this might accept
490 * several versions and set appropriate flags to handle them.
492 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
493 &remote_major, &remote_minor, remote_version) != 3) {
494 s = "Protocol mismatch.\n";
495 (void) atomicio(vwrite, sock_out, s, strlen(s));
496 logit("Bad protocol version identification '%.100s' "
497 "from %s port %d", client_version_string,
498 get_remote_ipaddr(), get_remote_port());
503 debug("Client protocol version %d.%d; client software version %.100s",
504 remote_major, remote_minor, remote_version);
506 active_state->compat = compat_datafellows(remote_version);
508 if ((datafellows & SSH_BUG_PROBE) != 0) {
509 logit("probed from %s with %s. Don't panic.",
510 get_remote_ipaddr(), client_version_string);
513 if ((datafellows & SSH_BUG_SCANNER) != 0) {
514 logit("scanned from %s with %s. Don't panic.",
515 get_remote_ipaddr(), client_version_string);
518 if ((datafellows & SSH_BUG_RSASIGMD5) != 0) {
519 logit("Client version \"%.100s\" uses unsafe RSA signature "
520 "scheme; disabling use of RSA keys", remote_version);
522 if ((datafellows & SSH_BUG_DERIVEKEY) != 0) {
523 fatal("Client version \"%.100s\" uses unsafe key agreement; "
524 "refusing connection", remote_version);
528 switch (remote_major) {
530 if (remote_minor == 99) {
531 if (options.protocol & SSH_PROTO_2)
537 if (!(options.protocol & SSH_PROTO_1)) {
541 if (remote_minor < 3) {
542 packet_disconnect("Your ssh version is too old and "
543 "is no longer supported. Please install a newer version.");
544 } else if (remote_minor == 3) {
545 /* note that this disables agent-forwarding */
550 if (options.protocol & SSH_PROTO_2) {
559 chop(server_version_string);
560 debug("Local version string %.200s", server_version_string);
563 s = "Protocol major versions differ.\n";
564 (void) atomicio(vwrite, sock_out, s, strlen(s));
567 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
569 server_version_string, client_version_string);
574 /* Destroy the host and server keys. They will no longer be needed. */
576 destroy_sensitive_data(void)
580 if (sensitive_data.server_key) {
581 key_free(sensitive_data.server_key);
582 sensitive_data.server_key = NULL;
584 for (i = 0; i < options.num_host_key_files; i++) {
585 if (sensitive_data.host_keys[i]) {
586 key_free(sensitive_data.host_keys[i]);
587 sensitive_data.host_keys[i] = NULL;
589 if (sensitive_data.host_certificates[i]) {
590 key_free(sensitive_data.host_certificates[i]);
591 sensitive_data.host_certificates[i] = NULL;
594 sensitive_data.ssh1_host_key = NULL;
595 explicit_bzero(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
598 /* Demote private to public keys for network child */
600 demote_sensitive_data(void)
605 if (sensitive_data.server_key) {
606 tmp = key_demote(sensitive_data.server_key);
607 key_free(sensitive_data.server_key);
608 sensitive_data.server_key = tmp;
611 for (i = 0; i < options.num_host_key_files; i++) {
612 if (sensitive_data.host_keys[i]) {
613 tmp = key_demote(sensitive_data.host_keys[i]);
614 key_free(sensitive_data.host_keys[i]);
615 sensitive_data.host_keys[i] = tmp;
616 if (tmp->type == KEY_RSA1)
617 sensitive_data.ssh1_host_key = tmp;
619 /* Certs do not need demotion */
622 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
626 privsep_preauth_child(void)
631 /* Enable challenge-response authentication for privilege separation */
632 privsep_challenge_enable();
635 /* Cache supported mechanism OIDs for later use */
636 if (options.gss_authentication)
637 ssh_gssapi_prepare_supported_oids();
641 arc4random_buf(rnd, sizeof(rnd));
643 RAND_seed(rnd, sizeof(rnd));
644 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
645 fatal("%s: RAND_bytes failed", __func__);
647 explicit_bzero(rnd, sizeof(rnd));
649 /* Demote the private keys to public keys. */
650 demote_sensitive_data();
652 /* Demote the child */
653 if (getuid() == 0 || geteuid() == 0) {
654 /* Change our root directory */
655 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
656 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
658 if (chdir("/") == -1)
659 fatal("chdir(\"/\"): %s", strerror(errno));
661 /* Drop our privileges */
662 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid,
663 (u_int)privsep_pw->pw_gid);
664 gidset[0] = privsep_pw->pw_gid;
665 if (setgroups(1, gidset) < 0)
666 fatal("setgroups: %.100s", strerror(errno));
667 permanently_set_uid(privsep_pw);
672 privsep_preauth(Authctxt *authctxt)
676 struct ssh_sandbox *box = NULL;
678 /* Set up unprivileged child process to deal with network data */
679 pmonitor = monitor_init();
680 /* Store a pointer to the kex for later rekeying */
681 pmonitor->m_pkex = &active_state->kex;
683 if (use_privsep == PRIVSEP_ON)
684 box = ssh_sandbox_init(pmonitor);
687 fatal("fork of unprivileged child failed");
688 } else if (pid != 0) {
689 debug2("Network child is on pid %ld", (long)pid);
691 pmonitor->m_pid = pid;
693 r = ssh_get_authentication_socket(&auth_sock);
695 error("Could not get agent socket: %s",
701 ssh_sandbox_parent_preauth(box, pid);
702 monitor_child_preauth(authctxt, pmonitor);
705 monitor_sync(pmonitor);
707 /* Wait for the child's exit status */
708 while (waitpid(pid, &status, 0) < 0) {
711 pmonitor->m_pid = -1;
712 fatal("%s: waitpid: %s", __func__, strerror(errno));
714 privsep_is_preauth = 0;
715 pmonitor->m_pid = -1;
716 if (WIFEXITED(status)) {
717 if (WEXITSTATUS(status) != 0)
718 fatal("%s: preauth child exited with status %d",
719 __func__, WEXITSTATUS(status));
720 } else if (WIFSIGNALED(status))
721 fatal("%s: preauth child terminated by signal %d",
722 __func__, WTERMSIG(status));
724 ssh_sandbox_parent_finish(box);
728 close(pmonitor->m_sendfd);
729 close(pmonitor->m_log_recvfd);
731 /* Arrange for logging to be sent to the monitor */
732 set_log_handler(mm_log_handler, pmonitor);
734 privsep_preauth_child();
735 setproctitle("%s", "[net]");
737 ssh_sandbox_child(box);
744 privsep_postauth(Authctxt *authctxt)
748 #ifdef DISABLE_FD_PASSING
751 if (authctxt->pw->pw_uid == 0 || options.use_login) {
753 /* File descriptor passing is broken or root login */
758 /* New socket pair */
759 monitor_reinit(pmonitor);
761 pmonitor->m_pid = fork();
762 if (pmonitor->m_pid == -1)
763 fatal("fork of unprivileged child failed");
764 else if (pmonitor->m_pid != 0) {
765 verbose("User child is on pid %ld", (long)pmonitor->m_pid);
766 buffer_clear(&loginmsg);
767 monitor_child_postauth(pmonitor);
775 close(pmonitor->m_sendfd);
776 pmonitor->m_sendfd = -1;
778 /* Demote the private keys to public keys. */
779 demote_sensitive_data();
782 arc4random_buf(rnd, sizeof(rnd));
784 RAND_seed(rnd, sizeof(rnd));
785 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
786 fatal("%s: RAND_bytes failed", __func__);
788 explicit_bzero(rnd, sizeof(rnd));
790 /* Drop privileges */
791 do_setusercontext(authctxt->pw);
794 /* It is safe now to apply the key state */
795 monitor_apply_keystate(pmonitor);
798 * Tell the packet layer that authentication was successful, since
799 * this information is not part of the key state.
801 packet_set_authenticated();
805 list_hostkey_types(void)
814 for (i = 0; i < options.num_host_key_files; i++) {
815 key = sensitive_data.host_keys[i];
817 key = sensitive_data.host_pubkeys[i];
818 if (key == NULL || key->type == KEY_RSA1)
820 /* Check that the key is accepted in HostkeyAlgorithms */
821 if (match_pattern_list(sshkey_ssh_name(key),
822 options.hostkeyalgorithms, 0) != 1) {
823 debug3("%s: %s key not permitted by HostkeyAlgorithms",
824 __func__, sshkey_ssh_name(key));
832 if (buffer_len(&b) > 0)
833 buffer_append(&b, ",", 1);
834 p = key_ssh_name(key);
835 buffer_append(&b, p, strlen(p));
837 /* for RSA we also support SHA2 signatures */
838 if (key->type == KEY_RSA) {
839 p = ",rsa-sha2-512,rsa-sha2-256";
840 buffer_append(&b, p, strlen(p));
844 /* If the private key has a cert peer, then list that too */
845 key = sensitive_data.host_certificates[i];
852 case KEY_ED25519_CERT:
853 if (buffer_len(&b) > 0)
854 buffer_append(&b, ",", 1);
855 p = key_ssh_name(key);
856 buffer_append(&b, p, strlen(p));
860 buffer_append(&b, "\0", 1);
861 ret = xstrdup(buffer_ptr(&b));
863 debug("list_hostkey_types: %s", ret);
868 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
873 for (i = 0; i < options.num_host_key_files; i++) {
878 case KEY_ED25519_CERT:
879 key = sensitive_data.host_certificates[i];
882 key = sensitive_data.host_keys[i];
883 if (key == NULL && !need_private)
884 key = sensitive_data.host_pubkeys[i];
887 if (key != NULL && key->type == type &&
888 (key->type != KEY_ECDSA || key->ecdsa_nid == nid))
889 return need_private ?
890 sensitive_data.host_keys[i] : key;
896 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
898 return get_hostkey_by_type(type, nid, 0, ssh);
902 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
904 return get_hostkey_by_type(type, nid, 1, ssh);
908 get_hostkey_by_index(int ind)
910 if (ind < 0 || ind >= options.num_host_key_files)
912 return (sensitive_data.host_keys[ind]);
916 get_hostkey_public_by_index(int ind, struct ssh *ssh)
918 if (ind < 0 || ind >= options.num_host_key_files)
920 return (sensitive_data.host_pubkeys[ind]);
924 get_hostkey_index(Key *key, int compare, struct ssh *ssh)
928 for (i = 0; i < options.num_host_key_files; i++) {
929 if (key_is_cert(key)) {
930 if (key == sensitive_data.host_certificates[i] ||
931 (compare && sensitive_data.host_certificates[i] &&
933 sensitive_data.host_certificates[i])))
936 if (key == sensitive_data.host_keys[i] ||
937 (compare && sensitive_data.host_keys[i] &&
938 sshkey_equal(key, sensitive_data.host_keys[i])))
940 if (key == sensitive_data.host_pubkeys[i] ||
941 (compare && sensitive_data.host_pubkeys[i] &&
942 sshkey_equal(key, sensitive_data.host_pubkeys[i])))
949 /* Inform the client of all hostkeys */
951 notify_hostkeys(struct ssh *ssh)
958 /* Some clients cannot cope with the hostkeys message, skip those. */
959 if (datafellows & SSH_BUG_HOSTKEYS)
962 if ((buf = sshbuf_new()) == NULL)
963 fatal("%s: sshbuf_new", __func__);
964 for (i = nkeys = 0; i < options.num_host_key_files; i++) {
965 key = get_hostkey_public_by_index(i, ssh);
966 if (key == NULL || key->type == KEY_UNSPEC ||
967 key->type == KEY_RSA1 || sshkey_is_cert(key))
969 fp = sshkey_fingerprint(key, options.fingerprint_hash,
971 debug3("%s: key %d: %s %s", __func__, i,
972 sshkey_ssh_name(key), fp);
975 packet_start(SSH2_MSG_GLOBAL_REQUEST);
976 packet_put_cstring("hostkeys-00@openssh.com");
977 packet_put_char(0); /* want-reply */
980 if ((r = sshkey_putb(key, buf)) != 0)
981 fatal("%s: couldn't put hostkey %d: %s",
982 __func__, i, ssh_err(r));
983 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf));
986 debug3("%s: sent %d hostkeys", __func__, nkeys);
988 fatal("%s: no hostkeys", __func__);
994 * returns 1 if connection should be dropped, 0 otherwise.
995 * dropping starts at connection #max_startups_begin with a probability
996 * of (max_startups_rate/100). the probability increases linearly until
997 * all connections are dropped for startups > max_startups
1000 drop_connection(int startups)
1004 if (startups < options.max_startups_begin)
1006 if (startups >= options.max_startups)
1008 if (options.max_startups_rate == 100)
1011 p = 100 - options.max_startups_rate;
1012 p *= startups - options.max_startups_begin;
1013 p /= options.max_startups - options.max_startups_begin;
1014 p += options.max_startups_rate;
1015 r = arc4random_uniform(100);
1017 debug("drop_connection: p %d, r %d", p, r);
1018 return (r < p) ? 1 : 0;
1024 if (options.version_addendum && *options.version_addendum != '\0')
1025 fprintf(stderr, "%s %s, %s\n",
1027 options.version_addendum, OPENSSL_VERSION);
1029 fprintf(stderr, "%s, %s\n",
1030 SSH_RELEASE, OPENSSL_VERSION);
1032 "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n"
1033 " [-E log_file] [-f config_file] [-g login_grace_time]\n"
1034 " [-h host_key_file] [-k key_gen_time] [-o option] [-p port]\n"
1041 send_rexec_state(int fd, Buffer *conf)
1045 debug3("%s: entering fd = %d config len %d", __func__, fd,
1049 * Protocol from reexec master to child:
1050 * string configuration
1051 * u_int ephemeral_key_follows
1052 * bignum e (only if ephemeral_key_follows == 1)
1058 * string rngseed (only if OpenSSL is not self-seeded)
1061 buffer_put_cstring(&m, buffer_ptr(conf));
1064 if (sensitive_data.server_key != NULL &&
1065 sensitive_data.server_key->type == KEY_RSA1) {
1066 buffer_put_int(&m, 1);
1067 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
1068 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
1069 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
1070 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
1071 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
1072 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
1075 buffer_put_int(&m, 0);
1077 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
1078 rexec_send_rng_seed(&m);
1081 if (ssh_msg_send(fd, 0, &m) == -1)
1082 fatal("%s: ssh_msg_send failed", __func__);
1086 debug3("%s: done", __func__);
1090 recv_rexec_state(int fd, Buffer *conf)
1096 debug3("%s: entering fd = %d", __func__, fd);
1100 if (ssh_msg_recv(fd, &m) == -1)
1101 fatal("%s: ssh_msg_recv failed", __func__);
1102 if (buffer_get_char(&m) != 0)
1103 fatal("%s: rexec version mismatch", __func__);
1105 cp = buffer_get_string(&m, &len);
1107 buffer_append(conf, cp, len + 1);
1110 if (buffer_get_int(&m)) {
1112 if (sensitive_data.server_key != NULL)
1113 key_free(sensitive_data.server_key);
1114 sensitive_data.server_key = key_new_private(KEY_RSA1);
1115 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
1116 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
1117 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
1118 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
1119 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
1120 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
1121 if (rsa_generate_additional_parameters(
1122 sensitive_data.server_key->rsa) != 0)
1123 fatal("%s: rsa_generate_additional_parameters "
1128 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
1129 rexec_recv_rng_seed(&m);
1134 debug3("%s: done", __func__);
1137 /* Accept a connection from inetd */
1139 server_accept_inetd(int *sock_in, int *sock_out)
1145 close(REEXEC_CONFIG_PASS_FD);
1146 *sock_in = *sock_out = dup(STDIN_FILENO);
1148 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
1149 close(REEXEC_STARTUP_PIPE_FD);
1152 *sock_in = dup(STDIN_FILENO);
1153 *sock_out = dup(STDOUT_FILENO);
1156 * We intentionally do not close the descriptors 0, 1, and 2
1157 * as our code for setting the descriptors won't work if
1158 * ttyfd happens to be one of those.
1160 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1161 dup2(fd, STDIN_FILENO);
1162 dup2(fd, STDOUT_FILENO);
1164 dup2(fd, STDERR_FILENO);
1165 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO))
1168 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
1172 * Listen for TCP connections
1177 int ret, listen_sock, on = 1;
1178 struct addrinfo *ai;
1179 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1183 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1184 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1186 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1187 fatal("Too many listen sockets. "
1188 "Enlarge MAX_LISTEN_SOCKS");
1189 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
1190 ntop, sizeof(ntop), strport, sizeof(strport),
1191 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
1192 error("getnameinfo failed: %.100s",
1193 ssh_gai_strerror(ret));
1196 /* Create socket for listening. */
1197 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1199 if (listen_sock < 0) {
1200 /* kernel may not support ipv6 */
1201 verbose("socket: %.100s", strerror(errno));
1204 if (set_nonblock(listen_sock) == -1) {
1209 * Set socket options.
1210 * Allow local port reuse in TIME_WAIT.
1212 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1213 &on, sizeof(on)) == -1)
1214 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1216 /* Only communicate in IPv6 over AF_INET6 sockets. */
1217 if (ai->ai_family == AF_INET6)
1218 sock_set_v6only(listen_sock);
1220 debug("Bind to port %s on %s.", strport, ntop);
1222 len = sizeof(socksize);
1223 getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, &socksize, &len);
1224 debug("Server TCP RWIN socket size: %d", socksize);
1226 /* Bind the socket to the desired port. */
1227 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1228 error("Bind to port %s on %s failed: %.200s.",
1229 strport, ntop, strerror(errno));
1233 listen_socks[num_listen_socks] = listen_sock;
1236 /* Start listening on the port. */
1237 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1238 fatal("listen on [%s]:%s: %.100s",
1239 ntop, strport, strerror(errno));
1240 logit("Server listening on %s port %s.", ntop, strport);
1242 freeaddrinfo(options.listen_addrs);
1244 if (!num_listen_socks)
1245 fatal("Cannot bind any address.");
1249 * The main TCP accept loop. Note that, for the non-debug case, returns
1250 * from this function are in a forked subprocess.
1253 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1256 int i, j, ret, maxfd;
1257 int key_used = 0, startups = 0;
1258 int startup_p[2] = { -1 , -1 };
1259 struct sockaddr_storage from;
1264 /* setup fd set for accept */
1267 for (i = 0; i < num_listen_socks; i++)
1268 if (listen_socks[i] > maxfd)
1269 maxfd = listen_socks[i];
1270 /* pipes connected to unauthenticated childs */
1271 startup_pipes = xcalloc(options.max_startups, sizeof(int));
1272 for (i = 0; i < options.max_startups; i++)
1273 startup_pipes[i] = -1;
1276 * Stay listening for connections until the system crashes or
1277 * the daemon is killed with a signal.
1280 if (received_sighup)
1283 fdset = xcalloc(howmany(maxfd + 1, NFDBITS),
1286 for (i = 0; i < num_listen_socks; i++)
1287 FD_SET(listen_socks[i], fdset);
1288 for (i = 0; i < options.max_startups; i++)
1289 if (startup_pipes[i] != -1)
1290 FD_SET(startup_pipes[i], fdset);
1292 /* Wait in select until there is a connection. */
1293 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1294 if (ret < 0 && errno != EINTR)
1295 error("select: %.100s", strerror(errno));
1296 if (received_sigterm) {
1297 logit("Received signal %d; terminating.",
1298 (int) received_sigterm);
1299 close_listen_socks();
1300 if (options.pid_file != NULL)
1301 unlink(options.pid_file);
1302 exit(received_sigterm == SIGTERM ? 0 : 255);
1304 if (key_used && key_do_regen) {
1305 generate_ephemeral_server_key();
1312 for (i = 0; i < options.max_startups; i++)
1313 if (startup_pipes[i] != -1 &&
1314 FD_ISSET(startup_pipes[i], fdset)) {
1316 * the read end of the pipe is ready
1317 * if the child has closed the pipe
1318 * after successful authentication
1319 * or if the child has died
1321 close(startup_pipes[i]);
1322 startup_pipes[i] = -1;
1325 for (i = 0; i < num_listen_socks; i++) {
1326 if (!FD_ISSET(listen_socks[i], fdset))
1328 fromlen = sizeof(from);
1329 *newsock = accept(listen_socks[i],
1330 (struct sockaddr *)&from, &fromlen);
1332 if (errno != EINTR && errno != EWOULDBLOCK &&
1333 errno != ECONNABORTED && errno != EAGAIN)
1334 error("accept: %.100s",
1336 if (errno == EMFILE || errno == ENFILE)
1340 if (unset_nonblock(*newsock) == -1) {
1344 if (drop_connection(startups) == 1) {
1345 debug("drop connection #%d", startups);
1349 if (pipe(startup_p) == -1) {
1354 if (rexec_flag && socketpair(AF_UNIX,
1355 SOCK_STREAM, 0, config_s) == -1) {
1356 error("reexec socketpair: %s",
1359 close(startup_p[0]);
1360 close(startup_p[1]);
1364 for (j = 0; j < options.max_startups; j++)
1365 if (startup_pipes[j] == -1) {
1366 startup_pipes[j] = startup_p[0];
1367 if (maxfd < startup_p[0])
1368 maxfd = startup_p[0];
1374 * Got connection. Fork a child to handle it, unless
1375 * we are in debugging mode.
1379 * In debugging mode. Close the listening
1380 * socket, and start processing the
1381 * connection without forking.
1383 debug("Server will not fork when running in debugging mode.");
1384 close_listen_socks();
1385 *sock_in = *newsock;
1386 *sock_out = *newsock;
1387 close(startup_p[0]);
1388 close(startup_p[1]);
1392 send_rexec_state(config_s[0],
1400 * Normal production daemon. Fork, and have
1401 * the child process the connection. The
1402 * parent continues listening.
1404 platform_pre_fork();
1405 if ((pid = fork()) == 0) {
1407 * Child. Close the listening and
1408 * max_startup sockets. Start using
1409 * the accepted socket. Reinitialize
1410 * logging (since our pid has changed).
1411 * We break out of the loop to handle
1414 platform_post_fork_child();
1415 startup_pipe = startup_p[1];
1416 close_startup_pipes();
1417 close_listen_socks();
1418 *sock_in = *newsock;
1419 *sock_out = *newsock;
1420 log_init(__progname,
1422 options.log_facility,
1429 /* Parent. Stay in the loop. */
1430 platform_post_fork_parent(pid);
1432 error("fork: %.100s", strerror(errno));
1434 debug("Forked child %ld.", (long)pid);
1436 close(startup_p[1]);
1439 send_rexec_state(config_s[0], &cfg);
1445 * Mark that the key has been used (it
1446 * was "given" to the child).
1448 if ((options.protocol & SSH_PROTO_1) &&
1450 /* Schedule server key regeneration alarm. */
1451 signal(SIGALRM, key_regeneration_alarm);
1452 alarm(options.key_regeneration_time);
1459 * Ensure that our random state differs
1460 * from that of the child
1463 arc4random_buf(rnd, sizeof(rnd));
1465 RAND_seed(rnd, sizeof(rnd));
1466 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
1467 fatal("%s: RAND_bytes failed", __func__);
1469 explicit_bzero(rnd, sizeof(rnd));
1472 /* child process check (or debug mode) */
1473 if (num_listen_socks < 0)
1480 * Main program for the daemon.
1483 main(int ac, char **av)
1485 extern char *optarg;
1487 int r, opt, i, j, on = 1;
1488 int sock_in = -1, sock_out = -1, newsock = -1;
1489 const char *remote_ip;
1491 char *fp, *line, *laddr, *logfile = NULL;
1492 int config_s[2] = { -1 , -1 };
1494 u_int64_t ibytes, obytes;
1500 struct connection_info *connection_info = get_connection_info(0, 0);
1502 ssh_malloc_init(); /* must be called before any mallocs */
1504 #ifdef HAVE_SECUREWARE
1505 (void)set_auth_parameters(ac, av);
1507 __progname = ssh_get_progname(av[0]);
1509 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
1512 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
1513 for (i = 0; i < ac; i++)
1514 saved_argv[i] = xstrdup(av[i]);
1515 saved_argv[i] = NULL;
1517 #ifndef HAVE_SETPROCTITLE
1518 /* Prepare for later setproctitle emulation */
1519 compat_init_setproctitle(ac, av);
1523 if (geteuid() == 0 && setgroups(0, NULL) == -1)
1524 debug("setgroups(): %.200s", strerror(errno));
1526 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1529 /* Initialize configuration options to their default values. */
1530 initialize_server_options(&options);
1532 /* Parse command-line arguments. */
1533 while ((opt = getopt(ac, av,
1534 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) {
1537 options.address_family = AF_INET;
1540 options.address_family = AF_INET6;
1543 config_file_name = optarg;
1546 if (options.num_host_cert_files >= MAX_HOSTCERTS) {
1547 fprintf(stderr, "too many host certificates.\n");
1550 options.host_cert_files[options.num_host_cert_files++] =
1551 derelativise_path(optarg);
1554 if (debug_flag == 0) {
1556 options.log_level = SYSLOG_LEVEL_DEBUG1;
1557 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1558 options.log_level++;
1583 options.log_level = SYSLOG_LEVEL_QUIET;
1586 options.server_key_bits = (int)strtonum(optarg, 256,
1590 options.ports_from_cmdline = 1;
1591 if (options.num_ports >= MAX_PORTS) {
1592 fprintf(stderr, "too many ports.\n");
1595 options.ports[options.num_ports++] = a2port(optarg);
1596 if (options.ports[options.num_ports-1] <= 0) {
1597 fprintf(stderr, "Bad port number.\n");
1602 if ((options.login_grace_time = convtime(optarg)) == -1) {
1603 fprintf(stderr, "Invalid login grace time.\n");
1608 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
1609 fprintf(stderr, "Invalid key regeneration interval.\n");
1614 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1615 fprintf(stderr, "too many host keys.\n");
1618 options.host_key_files[options.num_host_key_files++] =
1619 derelativise_path(optarg);
1628 if (parse_server_match_testspec(connection_info,
1633 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1634 if (utmp_len > HOST_NAME_MAX+1) {
1635 fprintf(stderr, "Invalid utmp length.\n");
1640 line = xstrdup(optarg);
1641 if (process_server_config_line(&options, line,
1642 "command-line", 0, NULL, NULL) != 0)
1652 if (rexeced_flag || inetd_flag)
1654 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
1655 fatal("sshd re-exec requires execution with an absolute path");
1657 closefrom(REEXEC_MIN_FREE_FD);
1659 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1662 OpenSSL_add_all_algorithms();
1665 /* If requested, redirect the logs to the specified logfile. */
1666 if (logfile != NULL)
1667 log_redirect_stderr_to(logfile);
1669 * Force logging to stderr until we have loaded the private host
1670 * key (unless started from inetd)
1672 log_init(__progname,
1673 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1674 SYSLOG_LEVEL_INFO : options.log_level,
1675 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1676 SYSLOG_FACILITY_AUTH : options.log_facility,
1677 log_stderr || !inetd_flag);
1680 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1681 * root's environment
1683 if (getenv("KRB5CCNAME") != NULL)
1684 (void) unsetenv("KRB5CCNAME");
1687 /* Cray can define user privs drop all privs now!
1688 * Not needed on PRIV_SU systems!
1693 sensitive_data.server_key = NULL;
1694 sensitive_data.ssh1_host_key = NULL;
1695 sensitive_data.have_ssh1_key = 0;
1696 sensitive_data.have_ssh2_key = 0;
1699 * If we're doing an extended config test, make sure we have all of
1700 * the parameters we need. If we're not doing an extended test,
1701 * do not silently ignore connection test params.
1703 if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0)
1704 fatal("user, host and addr are all required when testing "
1706 if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0)
1707 fatal("Config test connection parameter (-C) provided without "
1710 /* Fetch our configuration */
1713 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
1714 else if (strcasecmp(config_file_name, "none") != 0)
1715 load_server_config(config_file_name, &cfg);
1717 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1722 /* Fill in default values for those options not explicitly set. */
1723 fill_default_server_options(&options);
1725 /* challenge-response is implemented via keyboard interactive */
1726 if (options.challenge_response_authentication)
1727 options.kbd_interactive_authentication = 1;
1729 /* Check that options are sensible */
1730 if (options.authorized_keys_command_user == NULL &&
1731 (options.authorized_keys_command != NULL &&
1732 strcasecmp(options.authorized_keys_command, "none") != 0))
1733 fatal("AuthorizedKeysCommand set without "
1734 "AuthorizedKeysCommandUser");
1735 if (options.authorized_principals_command_user == NULL &&
1736 (options.authorized_principals_command != NULL &&
1737 strcasecmp(options.authorized_principals_command, "none") != 0))
1738 fatal("AuthorizedPrincipalsCommand set without "
1739 "AuthorizedPrincipalsCommandUser");
1742 * Check whether there is any path through configured auth methods.
1743 * Unfortunately it is not possible to verify this generally before
1744 * daemonisation in the presence of Match block, but this catches
1745 * and warns for trivial misconfigurations that could break login.
1747 if (options.num_auth_methods != 0) {
1748 if ((options.protocol & SSH_PROTO_1))
1749 fatal("AuthenticationMethods is not supported with "
1751 for (n = 0; n < options.num_auth_methods; n++) {
1752 if (auth2_methods_valid(options.auth_methods[n],
1756 if (n >= options.num_auth_methods)
1757 fatal("AuthenticationMethods cannot be satisfied by "
1758 "enabled authentication methods");
1761 /* set default channel AF */
1762 channel_set_af(options.address_family);
1764 /* Check that there are no remaining arguments. */
1766 fprintf(stderr, "Extra argument %s.\n", av[optind]);
1770 debug("sshd version %s, %s", SSH_VERSION,
1772 SSLeay_version(SSLEAY_VERSION)
1778 /* Store privilege separation user for later use if required. */
1779 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
1780 if (use_privsep || options.kerberos_authentication)
1781 fatal("Privilege separation user %s does not exist",
1784 explicit_bzero(privsep_pw->pw_passwd,
1785 strlen(privsep_pw->pw_passwd));
1786 privsep_pw = pwcopy(privsep_pw);
1787 free(privsep_pw->pw_passwd);
1788 privsep_pw->pw_passwd = xstrdup("*");
1792 /* load host keys */
1793 sensitive_data.host_keys = xcalloc(options.num_host_key_files,
1795 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
1798 if (options.host_key_agent) {
1799 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1800 setenv(SSH_AUTHSOCKET_ENV_NAME,
1801 options.host_key_agent, 1);
1802 if ((r = ssh_get_authentication_socket(NULL)) == 0)
1805 error("Could not connect to agent \"%s\": %s",
1806 options.host_key_agent, ssh_err(r));
1809 for (i = 0; i < options.num_host_key_files; i++) {
1810 if (options.host_key_files[i] == NULL)
1812 key = key_load_private(options.host_key_files[i], "", NULL);
1813 pubkey = key_load_public(options.host_key_files[i], NULL);
1814 if (pubkey == NULL && key != NULL)
1815 pubkey = key_demote(key);
1816 sensitive_data.host_keys[i] = key;
1817 sensitive_data.host_pubkeys[i] = pubkey;
1819 if (key == NULL && pubkey != NULL && pubkey->type != KEY_RSA1 &&
1821 debug("will rely on agent for hostkey %s",
1822 options.host_key_files[i]);
1823 keytype = pubkey->type;
1824 } else if (key != NULL) {
1825 keytype = key->type;
1827 error("Could not load host key: %s",
1828 options.host_key_files[i]);
1829 sensitive_data.host_keys[i] = NULL;
1830 sensitive_data.host_pubkeys[i] = NULL;
1836 sensitive_data.ssh1_host_key = key;
1837 sensitive_data.have_ssh1_key = 1;
1843 if (have_agent || key != NULL)
1844 sensitive_data.have_ssh2_key = 1;
1847 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash,
1848 SSH_FP_DEFAULT)) == NULL)
1849 fatal("sshkey_fingerprint failed");
1850 debug("%s host key #%d: %s %s",
1851 key ? "private" : "agent", i, keytype == KEY_RSA1 ?
1852 sshkey_type(pubkey) : sshkey_ssh_name(pubkey), fp);
1855 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
1856 logit("Disabling protocol version 1. Could not load host key");
1857 options.protocol &= ~SSH_PROTO_1;
1859 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1860 logit("Disabling protocol version 2. Could not load host key");
1861 options.protocol &= ~SSH_PROTO_2;
1863 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1864 logit("sshd: no hostkeys available -- exiting.");
1869 * Load certificates. They are stored in an array at identical
1870 * indices to the public keys that they relate to.
1872 sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
1874 for (i = 0; i < options.num_host_key_files; i++)
1875 sensitive_data.host_certificates[i] = NULL;
1877 for (i = 0; i < options.num_host_cert_files; i++) {
1878 if (options.host_cert_files[i] == NULL)
1880 key = key_load_public(options.host_cert_files[i], NULL);
1882 error("Could not load host certificate: %s",
1883 options.host_cert_files[i]);
1886 if (!key_is_cert(key)) {
1887 error("Certificate file is not a certificate: %s",
1888 options.host_cert_files[i]);
1892 /* Find matching private key */
1893 for (j = 0; j < options.num_host_key_files; j++) {
1894 if (key_equal_public(key,
1895 sensitive_data.host_keys[j])) {
1896 sensitive_data.host_certificates[j] = key;
1900 if (j >= options.num_host_key_files) {
1901 error("No matching private key for certificate: %s",
1902 options.host_cert_files[i]);
1906 sensitive_data.host_certificates[j] = key;
1907 debug("host certificate: #%d type %d %s", j, key->type,
1912 /* Check certain values for sanity. */
1913 if (options.protocol & SSH_PROTO_1) {
1914 if (options.server_key_bits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
1915 options.server_key_bits > OPENSSL_RSA_MAX_MODULUS_BITS) {
1916 fprintf(stderr, "Bad server key size.\n");
1920 * Check that server and host key lengths differ sufficiently. This
1921 * is necessary to make double encryption work with rsaref. Oh, I
1922 * hate software patents. I dont know if this can go? Niels
1924 if (options.server_key_bits >
1925 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1926 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1927 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1928 SSH_KEY_BITS_RESERVED) {
1929 options.server_key_bits =
1930 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1931 SSH_KEY_BITS_RESERVED;
1932 debug("Forcing server key to %d bits to make it differ from host key.",
1933 options.server_key_bits);
1941 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1942 (S_ISDIR(st.st_mode) == 0))
1943 fatal("Missing privilege separation directory: %s",
1944 _PATH_PRIVSEP_CHROOT_DIR);
1947 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1948 (st.st_uid != getuid () ||
1949 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1951 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1953 fatal("%s must be owned by root and not group or "
1954 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1957 if (test_flag > 1) {
1958 if (server_match_spec_complete(connection_info) == 1)
1959 parse_server_match_config(&options, connection_info);
1960 dump_config(&options);
1963 /* Configuration looks good, so exit if in test mode. */
1968 * Clear out any supplemental groups we may have inherited. This
1969 * prevents inadvertent creation of files with bad modes (in the
1970 * portable version at least, it's certainly possible for PAM
1971 * to create a file, and we can't control the code in every
1972 * module which might be used).
1974 if (setgroups(0, NULL) < 0)
1975 debug("setgroups() failed: %.200s", strerror(errno));
1978 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
1979 for (i = 0; i < rexec_argc; i++) {
1980 debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1981 rexec_argv[i] = saved_argv[i];
1983 rexec_argv[rexec_argc] = "-R";
1984 rexec_argv[rexec_argc + 1] = NULL;
1987 /* Ensure that umask disallows at least group and world write */
1988 new_umask = umask(0077) | 0022;
1989 (void) umask(new_umask);
1991 /* Initialize the log (it is reinitialized below in case we forked). */
1992 if (debug_flag && (!inetd_flag || rexeced_flag))
1994 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1997 * If not in debugging mode, and not started from inetd, disconnect
1998 * from the controlling terminal, and fork. The original process
2001 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
2004 #endif /* TIOCNOTTY */
2005 if (daemon(0, 0) < 0)
2006 fatal("daemon() failed: %.200s", strerror(errno));
2008 /* Disconnect from the controlling tty. */
2010 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
2012 (void) ioctl(fd, TIOCNOTTY, NULL);
2015 #endif /* TIOCNOTTY */
2017 /* Reinitialize the log (because of the fork above). */
2018 log_init(__progname, options.log_level, options.log_facility, log_stderr);
2020 /* Avoid killing the process in high-pressure swapping environments. */
2021 if (!inetd_flag && madvise(NULL, 0, MADV_PROTECT) != 0)
2022 debug("madvise(): %.200s", strerror(errno));
2024 /* Chdir to the root directory so that the current disk can be
2025 unmounted if desired. */
2026 if (chdir("/") == -1)
2027 error("chdir(\"/\"): %s", strerror(errno));
2029 /* ignore SIGPIPE */
2030 signal(SIGPIPE, SIG_IGN);
2032 /* Get a connection, either from inetd or a listening TCP socket */
2034 server_accept_inetd(&sock_in, &sock_out);
2036 platform_pre_listen();
2039 if (options.protocol & SSH_PROTO_1)
2040 generate_ephemeral_server_key();
2042 signal(SIGHUP, sighup_handler);
2043 signal(SIGCHLD, main_sigchld_handler);
2044 signal(SIGTERM, sigterm_handler);
2045 signal(SIGQUIT, sigterm_handler);
2048 * Write out the pid file after the sigterm handler
2049 * is setup and the listen sockets are bound
2051 if (options.pid_file != NULL && !debug_flag) {
2052 FILE *f = fopen(options.pid_file, "w");
2055 error("Couldn't create pid file \"%s\": %s",
2056 options.pid_file, strerror(errno));
2058 fprintf(f, "%ld\n", (long) getpid());
2063 /* Accept a connection and return in a forked child */
2064 server_accept_loop(&sock_in, &sock_out,
2065 &newsock, config_s);
2068 /* This is the child processing a new connection. */
2069 setproctitle("%s", "[accepted]");
2072 * Create a new session and process group since the 4.4BSD
2073 * setlogin() affects the entire process group. We don't
2074 * want the child to be able to affect the parent.
2076 #if !defined(SSHD_ACQUIRES_CTTY)
2078 * If setsid is called, on some platforms sshd will later acquire a
2079 * controlling terminal which will result in "could not set
2080 * controlling tty" errors.
2082 if (!debug_flag && !inetd_flag && setsid() < 0)
2083 error("setsid: %.100s", strerror(errno));
2089 debug("rexec start in %d out %d newsock %d pipe %d sock %d",
2090 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
2091 dup2(newsock, STDIN_FILENO);
2092 dup2(STDIN_FILENO, STDOUT_FILENO);
2093 if (startup_pipe == -1)
2094 close(REEXEC_STARTUP_PIPE_FD);
2095 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
2096 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
2097 close(startup_pipe);
2098 startup_pipe = REEXEC_STARTUP_PIPE_FD;
2101 dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
2104 execv(rexec_argv[0], rexec_argv);
2106 /* Reexec has failed, fall back and continue */
2107 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
2108 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
2109 log_init(__progname, options.log_level,
2110 options.log_facility, log_stderr);
2113 close(REEXEC_CONFIG_PASS_FD);
2114 newsock = sock_out = sock_in = dup(STDIN_FILENO);
2115 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
2116 dup2(fd, STDIN_FILENO);
2117 dup2(fd, STDOUT_FILENO);
2118 if (fd > STDERR_FILENO)
2121 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
2122 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
2125 /* Executed child processes don't need these. */
2126 fcntl(sock_out, F_SETFD, FD_CLOEXEC);
2127 fcntl(sock_in, F_SETFD, FD_CLOEXEC);
2130 * Disable the key regeneration alarm. We will not regenerate the
2131 * key since we are no longer in a position to give it to anyone. We
2132 * will not restart on SIGHUP since it no longer makes sense.
2135 signal(SIGALRM, SIG_DFL);
2136 signal(SIGHUP, SIG_DFL);
2137 signal(SIGTERM, SIG_DFL);
2138 signal(SIGQUIT, SIG_DFL);
2139 signal(SIGCHLD, SIG_DFL);
2140 signal(SIGINT, SIG_DFL);
2144 * Initialize the resolver. This may not happen automatically
2145 * before privsep chroot().
2147 if ((_res.options & RES_INIT) == 0) {
2148 debug("res_init()");
2153 * Force GSS-API to parse its configuration and load any
2154 * mechanism plugins.
2158 OM_uint32 minor_status;
2159 gss_indicate_mechs(&minor_status, &mechs);
2160 gss_release_oid_set(&minor_status, &mechs);
2166 * Register our connection. This turns encryption off because we do
2169 packet_set_connection(sock_in, sock_out);
2170 packet_set_server();
2172 /* Set SO_KEEPALIVE if requested. */
2173 if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
2174 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
2175 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
2177 if ((remote_port = get_remote_port()) < 0) {
2178 debug("get_remote_port failed");
2183 * We use get_canonical_hostname with usedns = 0 instead of
2184 * get_remote_ipaddr here so IP options will be checked.
2186 (void) get_canonical_hostname(0);
2188 * The rest of the code depends on the fact that
2189 * get_remote_ipaddr() caches the remote ip, even if
2190 * the socket goes away.
2192 remote_ip = get_remote_ipaddr();
2194 #ifdef SSH_AUDIT_EVENTS
2195 audit_connection_from(remote_ip, remote_port);
2198 allow_severity = options.log_facility|LOG_INFO;
2199 deny_severity = options.log_facility|LOG_WARNING;
2200 /* Check whether logins are denied from this host. */
2201 if (packet_connection_is_on_socket()) {
2202 struct request_info req;
2204 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
2207 if (!hosts_access(&req)) {
2208 debug("Connection refused by tcp wrapper");
2211 fatal("libwrap refuse returns");
2214 #endif /* LIBWRAP */
2216 /* Log the connection. */
2217 laddr = get_local_ipaddr(sock_in);
2218 verbose("Connection from %s port %d on %s port %d",
2219 remote_ip, remote_port, laddr, get_local_port());
2223 * We don't want to listen forever unless the other side
2224 * successfully authenticates itself. So we set up an alarm which is
2225 * cleared after successful authentication. A limit of zero
2226 * indicates no limit. Note that we don't set the alarm in debugging
2227 * mode; it is just annoying to have the server exit just when you
2228 * are about to discover the bug.
2230 signal(SIGALRM, grace_alarm_handler);
2232 alarm(options.login_grace_time);
2234 sshd_exchange_identification(sock_in, sock_out);
2236 /* In inetd mode, generate ephemeral key only for proto 1 connections */
2237 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL)
2238 generate_ephemeral_server_key();
2240 packet_set_nonblocking();
2242 /* allocate authentication context */
2243 authctxt = xcalloc(1, sizeof(*authctxt));
2245 authctxt->loginmsg = &loginmsg;
2247 /* XXX global for cleanup, access from other modules */
2248 the_authctxt = authctxt;
2250 /* prepare buffer to collect messages to display to user after login */
2251 buffer_init(&loginmsg);
2255 if (privsep_preauth(authctxt) == 1)
2257 } else if (compat20 && have_agent) {
2258 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
2259 error("Unable to get agent socket: %s", ssh_err(r));
2264 /* perform the key exchange */
2265 /* authenticate user and start session */
2268 do_authentication2(authctxt);
2272 do_authentication(authctxt);
2274 fatal("ssh1 not supported");
2278 * If we use privilege separation, the unprivileged child transfers
2279 * the current keystate and exits
2282 mm_send_keystate(pmonitor);
2288 * Cancel the alarm we set to limit the time taken for
2292 signal(SIGALRM, SIG_DFL);
2293 authctxt->authenticated = 1;
2294 if (startup_pipe != -1) {
2295 close(startup_pipe);
2299 #ifdef SSH_AUDIT_EVENTS
2300 audit_event(SSH_AUTH_SUCCESS);
2304 if (options.gss_authentication) {
2305 temporarily_use_uid(authctxt->pw);
2306 ssh_gssapi_storecreds();
2311 if (options.use_pam) {
2318 * In privilege separation, we fork another child and prepare
2319 * file descriptor passing.
2322 privsep_postauth(authctxt);
2323 /* the monitor process [priv] will not return */
2325 destroy_sensitive_data();
2328 packet_set_timeout(options.client_alive_interval,
2329 options.client_alive_count_max);
2331 /* Try to send all our hostkeys to the client */
2333 notify_hostkeys(active_state);
2335 /* Start session. */
2336 do_authenticated(authctxt);
2338 /* The connection has been terminated. */
2339 packet_get_bytes(&ibytes, &obytes);
2340 verbose("Transferred: sent %llu, received %llu bytes",
2341 (unsigned long long)obytes, (unsigned long long)ibytes);
2343 verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
2346 if (options.use_pam)
2348 #endif /* USE_PAM */
2350 #ifdef SSH_AUDIT_EVENTS
2351 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
2364 * Decrypt session_key_int using our private server key and private host key
2365 * (key with larger modulus first).
2368 ssh1_session_key(BIGNUM *session_key_int)
2372 if (BN_cmp(sensitive_data.server_key->rsa->n,
2373 sensitive_data.ssh1_host_key->rsa->n) > 0) {
2374 /* Server key has bigger modulus. */
2375 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
2376 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
2377 SSH_KEY_BITS_RESERVED) {
2378 fatal("do_connection: %s: "
2379 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
2380 get_remote_ipaddr(),
2381 BN_num_bits(sensitive_data.server_key->rsa->n),
2382 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
2383 SSH_KEY_BITS_RESERVED);
2385 if (rsa_private_decrypt(session_key_int, session_key_int,
2386 sensitive_data.server_key->rsa) != 0)
2388 if (rsa_private_decrypt(session_key_int, session_key_int,
2389 sensitive_data.ssh1_host_key->rsa) != 0)
2392 /* Host key has bigger modulus (or they are equal). */
2393 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
2394 BN_num_bits(sensitive_data.server_key->rsa->n) +
2395 SSH_KEY_BITS_RESERVED) {
2396 fatal("do_connection: %s: "
2397 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
2398 get_remote_ipaddr(),
2399 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
2400 BN_num_bits(sensitive_data.server_key->rsa->n),
2401 SSH_KEY_BITS_RESERVED);
2403 if (rsa_private_decrypt(session_key_int, session_key_int,
2404 sensitive_data.ssh1_host_key->rsa) != 0)
2406 if (rsa_private_decrypt(session_key_int, session_key_int,
2407 sensitive_data.server_key->rsa) != 0)
2421 BIGNUM *session_key_int, *fake_key_int, *real_key_int;
2422 u_char session_key[SSH_SESSION_KEY_LENGTH];
2423 u_char fake_key_bytes[4096 / 8];
2424 size_t fake_key_len;
2426 u_int cipher_type, auth_mask, protocol_flags;
2429 * Generate check bytes that the client must send back in the user
2430 * packet in order for it to be accepted; this is used to defy ip
2431 * spoofing attacks. Note that this only works against somebody
2432 * doing IP spoofing from a remote machine; any machine on the local
2433 * network can still see outgoing packets and catch the random
2434 * cookie. This only affects rhosts authentication, and this is one
2435 * of the reasons why it is inherently insecure.
2437 arc4random_buf(cookie, sizeof(cookie));
2440 * Send our public key. We include in the packet 64 bits of random
2441 * data that must be matched in the reply in order to prevent IP
2444 packet_start(SSH_SMSG_PUBLIC_KEY);
2445 for (i = 0; i < 8; i++)
2446 packet_put_char(cookie[i]);
2448 /* Store our public server RSA key. */
2449 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
2450 packet_put_bignum(sensitive_data.server_key->rsa->e);
2451 packet_put_bignum(sensitive_data.server_key->rsa->n);
2453 /* Store our public host RSA key. */
2454 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
2455 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
2456 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
2458 /* Put protocol flags. */
2459 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
2461 /* Declare which ciphers we support. */
2462 packet_put_int(cipher_mask_ssh1(0));
2464 /* Declare supported authentication types. */
2466 if (options.rhosts_rsa_authentication)
2467 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
2468 if (options.rsa_authentication)
2469 auth_mask |= 1 << SSH_AUTH_RSA;
2470 if (options.challenge_response_authentication == 1)
2471 auth_mask |= 1 << SSH_AUTH_TIS;
2472 if (options.password_authentication)
2473 auth_mask |= 1 << SSH_AUTH_PASSWORD;
2474 packet_put_int(auth_mask);
2476 /* Send the packet and wait for it to be sent. */
2478 packet_write_wait();
2480 debug("Sent %d bit server key and %d bit host key.",
2481 BN_num_bits(sensitive_data.server_key->rsa->n),
2482 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
2484 /* Read clients reply (cipher type and session key). */
2485 packet_read_expect(SSH_CMSG_SESSION_KEY);
2487 /* Get cipher type and check whether we accept this. */
2488 cipher_type = packet_get_char();
2490 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
2491 packet_disconnect("Warning: client selects unsupported cipher.");
2493 /* Get check bytes from the packet. These must match those we
2494 sent earlier with the public key packet. */
2495 for (i = 0; i < 8; i++)
2496 if (cookie[i] != packet_get_char())
2497 packet_disconnect("IP Spoofing check bytes do not match.");
2499 debug("Encryption type: %.200s", cipher_name(cipher_type));
2501 /* Get the encrypted integer. */
2502 if ((real_key_int = BN_new()) == NULL)
2503 fatal("do_ssh1_kex: BN_new failed");
2504 packet_get_bignum(real_key_int);
2506 protocol_flags = packet_get_int();
2507 packet_set_protocol_flags(protocol_flags);
2510 /* Setup a fake key in case RSA decryption fails */
2511 if ((fake_key_int = BN_new()) == NULL)
2512 fatal("do_ssh1_kex: BN_new failed");
2513 fake_key_len = BN_num_bytes(real_key_int);
2514 if (fake_key_len > sizeof(fake_key_bytes))
2515 fake_key_len = sizeof(fake_key_bytes);
2516 arc4random_buf(fake_key_bytes, fake_key_len);
2517 if (BN_bin2bn(fake_key_bytes, fake_key_len, fake_key_int) == NULL)
2518 fatal("do_ssh1_kex: BN_bin2bn failed");
2520 /* Decrypt real_key_int using host/server keys */
2521 rsafail = PRIVSEP(ssh1_session_key(real_key_int));
2522 /* If decryption failed, use the fake key. Else, the real key. */
2524 session_key_int = fake_key_int;
2526 session_key_int = real_key_int;
2529 * Extract session key from the decrypted integer. The key is in the
2530 * least significant 256 bits of the integer; the first byte of the
2531 * key is in the highest bits.
2533 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8);
2534 len = BN_num_bytes(session_key_int);
2535 if (len < 0 || (u_int)len > sizeof(session_key)) {
2536 error("do_ssh1_kex: bad session key len from %s: "
2537 "session_key_int %d > sizeof(session_key) %lu",
2538 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
2541 explicit_bzero(session_key, sizeof(session_key));
2542 BN_bn2bin(session_key_int,
2543 session_key + sizeof(session_key) - len);
2545 derive_ssh1_session_id(
2546 sensitive_data.ssh1_host_key->rsa->n,
2547 sensitive_data.server_key->rsa->n,
2548 cookie, session_id);
2550 * Xor the first 16 bytes of the session key with the
2553 for (i = 0; i < 16; i++)
2554 session_key[i] ^= session_id[i];
2557 /* Destroy the private and public keys. No longer. */
2558 destroy_sensitive_data();
2561 mm_ssh1_session_id(session_id);
2563 /* Destroy the decrypted integer. It is no longer needed. */
2564 BN_clear_free(real_key_int);
2565 BN_clear_free(fake_key_int);
2567 /* Set the session key. From this on all communications will be encrypted. */
2568 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
2570 /* Destroy our copy of the session key. It is no longer needed. */
2571 explicit_bzero(session_key, sizeof(session_key));
2573 debug("Received session key; encryption turned on.");
2575 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
2576 packet_start(SSH_SMSG_SUCCESS);
2578 packet_write_wait();
2583 sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen,
2584 const u_char *data, size_t dlen, const char *alg, u_int flag)
2587 u_int xxx_slen, xxx_dlen = dlen;
2590 if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen,
2592 fatal("%s: key_sign failed", __func__);
2595 } else if (use_privsep) {
2596 if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen,
2598 fatal("%s: pubkey_sign failed", __func__);
2602 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen,
2603 data, dlen, alg, datafellows)) != 0)
2604 fatal("%s: ssh_agent_sign failed: %s",
2605 __func__, ssh_err(r));
2610 /* SSH2 key exchange */
2614 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
2618 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
2619 options.kex_algorithms);
2620 myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(
2622 myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(
2624 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2625 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2627 if (options.compression == COMP_NONE) {
2628 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2629 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
2630 } else if (options.compression == COMP_DELAYED) {
2631 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2632 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
2635 if (options.rekey_limit || options.rekey_interval)
2636 packet_set_rekey_limits(options.rekey_limit,
2637 (time_t)options.rekey_interval);
2639 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
2640 list_hostkey_types());
2642 /* start key exchange */
2643 if ((r = kex_setup(active_state, myproposal)) != 0)
2644 fatal("kex_setup: %s", ssh_err(r));
2645 kex = active_state->kex;
2647 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
2648 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
2649 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
2650 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
2651 # ifdef OPENSSL_HAS_ECC
2652 kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
2655 kex->kex[KEX_C25519_SHA256] = kexc25519_server;
2657 kex->client_version_string=client_version_string;
2658 kex->server_version_string=server_version_string;
2659 kex->load_host_public_key=&get_hostkey_public_by_type;
2660 kex->load_host_private_key=&get_hostkey_private_by_type;
2661 kex->host_key_index=&get_hostkey_index;
2662 kex->sign = sshd_hostkey_sign;
2664 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state);
2666 session_id2 = kex->session_id;
2667 session_id2_len = kex->session_id_len;
2670 /* send 1st encrypted/maced/compressed message */
2671 packet_start(SSH2_MSG_IGNORE);
2672 packet_put_cstring("markus");
2674 packet_write_wait();
2679 /* server specific fatal cleanup */
2684 do_cleanup(the_authctxt);
2685 if (use_privsep && privsep_is_preauth &&
2686 pmonitor != NULL && pmonitor->m_pid > 1) {
2687 debug("Killing privsep child %d", pmonitor->m_pid);
2688 if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
2690 error("%s: kill(%d): %s", __func__,
2691 pmonitor->m_pid, strerror(errno));
2694 #ifdef SSH_AUDIT_EVENTS
2695 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2696 if (!use_privsep || mm_is_monitor())
2697 audit_event(SSH_CONNECTION_ABANDON);