1 /* $OpenBSD: sshd.c,v 1.458 2015/08/20 22:32:42 deraadt 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"
136 #include "ssh-sandbox.h"
152 #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
153 #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
154 #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
155 #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
157 extern char *__progname;
159 /* Server configuration options. */
160 ServerOptions options;
162 /* Name of the server configuration file. */
163 char *config_file_name = _PATH_SERVER_CONFIG_FILE;
166 * Debug mode flag. This can be set on the command line. If debug
167 * mode is enabled, extra debugging output will be sent to the system
168 * log, the daemon will not go to background, and will exit after processing
169 * the first connection.
173 /* Flag indicating that the daemon should only test the configuration and keys. */
176 /* Flag indicating that the daemon is being started from inetd. */
179 /* Flag indicating that sshd should not detach and become a daemon. */
180 int no_daemon_flag = 0;
182 /* debug goes to stderr unless inetd_flag is set */
185 /* Saved arguments to main(). */
190 int rexeced_flag = 0;
196 * The sockets that the server is listening; this is used in the SIGHUP
199 #define MAX_LISTEN_SOCKS 16
200 int listen_socks[MAX_LISTEN_SOCKS];
201 int num_listen_socks = 0;
204 * the client's version string, passed by sshd2 in compat mode. if != NULL,
205 * sshd will skip the version-number exchange
207 char *client_version_string = NULL;
208 char *server_version_string = NULL;
210 /* Daemon's agent connection */
215 * Any really sensitive data in the application is contained in this
216 * structure. The idea is that this structure could be locked into memory so
217 * that the pages do not get written into swap. However, there are some
218 * problems. The private key contains BIGNUMs, and we do not (in principle)
219 * have access to the internals of them, and locking just the structure is
220 * not very useful. Currently, memory locking is not implemented.
223 Key *server_key; /* ephemeral server key */
224 Key *ssh1_host_key; /* ssh1 host key */
225 Key **host_keys; /* all private host keys */
226 Key **host_pubkeys; /* all public host keys */
227 Key **host_certificates; /* all public host certificates */
230 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
234 * Flag indicating whether the RSA server key needs to be regenerated.
235 * Is set in the SIGALRM handler and cleared when the key is regenerated.
237 static volatile sig_atomic_t key_do_regen = 0;
239 /* This is set to true when a signal is received. */
240 static volatile sig_atomic_t received_sighup = 0;
241 static volatile sig_atomic_t received_sigterm = 0;
243 /* session identifier, used by RSA-auth */
244 u_char session_id[16];
247 u_char *session_id2 = NULL;
248 u_int session_id2_len = 0;
250 /* record remote hostname or ip */
251 u_int utmp_len = HOST_NAME_MAX+1;
253 /* options.max_startup sized array of fd ints */
254 int *startup_pipes = NULL;
255 int startup_pipe; /* in child */
257 /* variables used for privilege separation */
258 int use_privsep = -1;
259 struct monitor *pmonitor = NULL;
260 int privsep_is_preauth = 1;
262 /* global authentication context */
263 Authctxt *the_authctxt = NULL;
265 /* sshd_config buffer */
268 /* message to be displayed after login */
271 /* Unprivileged user */
272 struct passwd *privsep_pw = NULL;
274 /* Prototypes for various functions defined later in this file. */
275 void destroy_sensitive_data(void);
276 void demote_sensitive_data(void);
279 static void do_ssh1_kex(void);
281 static void do_ssh2_kex(void);
284 * Close all listening sockets
287 close_listen_socks(void)
291 for (i = 0; i < num_listen_socks; i++)
292 close(listen_socks[i]);
293 num_listen_socks = -1;
297 close_startup_pipes(void)
302 for (i = 0; i < options.max_startups; i++)
303 if (startup_pipes[i] != -1)
304 close(startup_pipes[i]);
308 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
309 * the effect is to reread the configuration file (and to regenerate
315 sighup_handler(int sig)
317 int save_errno = errno;
320 signal(SIGHUP, sighup_handler);
325 * Called from the main program after receiving SIGHUP.
326 * Restarts the server.
331 logit("Received SIGHUP; restarting.");
332 platform_pre_restart();
333 close_listen_socks();
334 close_startup_pipes();
335 alarm(0); /* alarm timer persists across exec */
336 signal(SIGHUP, SIG_IGN); /* will be restored after exec */
337 execv(saved_argv[0], saved_argv);
338 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
344 * Generic signal handler for terminating signals in the master daemon.
348 sigterm_handler(int sig)
350 received_sigterm = sig;
354 * SIGCHLD handler. This is called whenever a child dies. This will then
355 * reap any zombies left by exited children.
359 main_sigchld_handler(int sig)
361 int save_errno = errno;
365 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
366 (pid < 0 && errno == EINTR))
369 signal(SIGCHLD, main_sigchld_handler);
374 * Signal handler for the alarm after the login grace period has expired.
378 grace_alarm_handler(int sig)
380 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
381 kill(pmonitor->m_pid, SIGALRM);
384 * Try to kill any processes that we have spawned, E.g. authorized
385 * keys command helpers.
387 if (getpgid(0) == getpid()) {
388 signal(SIGTERM, SIG_IGN);
392 /* Log error and exit. */
393 sigdie("Timeout before authentication for %s", get_remote_ipaddr());
397 * Signal handler for the key regeneration alarm. Note that this
398 * alarm only occurs in the daemon waiting for connections, and it does not
399 * do anything with the private key or random state before forking.
400 * Thus there should be no concurrency control/asynchronous execution
404 generate_ephemeral_server_key(void)
406 verbose("Generating %s%d bit RSA key.",
407 sensitive_data.server_key ? "new " : "", options.server_key_bits);
408 if (sensitive_data.server_key != NULL)
409 key_free(sensitive_data.server_key);
410 sensitive_data.server_key = key_generate(KEY_RSA1,
411 options.server_key_bits);
412 verbose("RSA key generation complete.");
414 arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
419 key_regeneration_alarm(int sig)
421 int save_errno = errno;
423 signal(SIGALRM, SIG_DFL);
429 sshd_exchange_identification(int sock_in, int sock_out)
433 int remote_major, remote_minor;
435 char *s, *newline = "\n";
436 char buf[256]; /* Must not be larger than remote_version. */
437 char remote_version[256]; /* Must be at least as big as buf. */
439 if ((options.protocol & SSH_PROTO_1) &&
440 (options.protocol & SSH_PROTO_2)) {
441 major = PROTOCOL_MAJOR_1;
443 } else if (options.protocol & SSH_PROTO_2) {
444 major = PROTOCOL_MAJOR_2;
445 minor = PROTOCOL_MINOR_2;
448 major = PROTOCOL_MAJOR_1;
449 minor = PROTOCOL_MINOR_1;
452 xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s",
453 major, minor, SSH_VERSION,
454 *options.version_addendum == '\0' ? "" : " ",
455 options.version_addendum, newline);
457 /* Send our protocol version identification. */
458 if (roaming_atomicio(vwrite, sock_out, server_version_string,
459 strlen(server_version_string))
460 != strlen(server_version_string)) {
461 logit("Could not write ident string to %s", get_remote_ipaddr());
465 /* Read other sides version identification. */
466 memset(buf, 0, sizeof(buf));
467 for (i = 0; i < sizeof(buf) - 1; i++) {
468 if (roaming_atomicio(read, sock_in, &buf[i], 1) != 1) {
469 logit("Did not receive identification string from %s",
470 get_remote_ipaddr());
473 if (buf[i] == '\r') {
475 /* Kludge for F-Secure Macintosh < 1.0.2 */
477 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
481 if (buf[i] == '\n') {
486 buf[sizeof(buf) - 1] = 0;
487 client_version_string = xstrdup(buf);
490 * Check that the versions match. In future this might accept
491 * several versions and set appropriate flags to handle them.
493 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
494 &remote_major, &remote_minor, remote_version) != 3) {
495 s = "Protocol mismatch.\n";
496 (void) atomicio(vwrite, sock_out, s, strlen(s));
497 logit("Bad protocol version identification '%.100s' "
498 "from %s port %d", client_version_string,
499 get_remote_ipaddr(), get_remote_port());
504 debug("Client protocol version %d.%d; client software version %.100s",
505 remote_major, remote_minor, remote_version);
507 active_state->compat = compat_datafellows(remote_version);
509 if ((datafellows & SSH_BUG_PROBE) != 0) {
510 logit("probed from %s with %s. Don't panic.",
511 get_remote_ipaddr(), client_version_string);
514 if ((datafellows & SSH_BUG_SCANNER) != 0) {
515 logit("scanned from %s with %s. Don't panic.",
516 get_remote_ipaddr(), client_version_string);
519 if ((datafellows & SSH_BUG_RSASIGMD5) != 0) {
520 logit("Client version \"%.100s\" uses unsafe RSA signature "
521 "scheme; disabling use of RSA keys", remote_version);
523 if ((datafellows & SSH_BUG_DERIVEKEY) != 0) {
524 fatal("Client version \"%.100s\" uses unsafe key agreement; "
525 "refusing connection", remote_version);
529 switch (remote_major) {
531 if (remote_minor == 99) {
532 if (options.protocol & SSH_PROTO_2)
538 if (!(options.protocol & SSH_PROTO_1)) {
542 if (remote_minor < 3) {
543 packet_disconnect("Your ssh version is too old and "
544 "is no longer supported. Please install a newer version.");
545 } else if (remote_minor == 3) {
546 /* note that this disables agent-forwarding */
551 if (options.protocol & SSH_PROTO_2) {
560 chop(server_version_string);
561 debug("Local version string %.200s", server_version_string);
564 s = "Protocol major versions differ.\n";
565 (void) atomicio(vwrite, sock_out, s, strlen(s));
568 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
570 server_version_string, client_version_string);
575 /* Destroy the host and server keys. They will no longer be needed. */
577 destroy_sensitive_data(void)
581 if (sensitive_data.server_key) {
582 key_free(sensitive_data.server_key);
583 sensitive_data.server_key = NULL;
585 for (i = 0; i < options.num_host_key_files; i++) {
586 if (sensitive_data.host_keys[i]) {
587 key_free(sensitive_data.host_keys[i]);
588 sensitive_data.host_keys[i] = NULL;
590 if (sensitive_data.host_certificates[i]) {
591 key_free(sensitive_data.host_certificates[i]);
592 sensitive_data.host_certificates[i] = NULL;
595 sensitive_data.ssh1_host_key = NULL;
596 explicit_bzero(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
599 /* Demote private to public keys for network child */
601 demote_sensitive_data(void)
606 if (sensitive_data.server_key) {
607 tmp = key_demote(sensitive_data.server_key);
608 key_free(sensitive_data.server_key);
609 sensitive_data.server_key = tmp;
612 for (i = 0; i < options.num_host_key_files; i++) {
613 if (sensitive_data.host_keys[i]) {
614 tmp = key_demote(sensitive_data.host_keys[i]);
615 key_free(sensitive_data.host_keys[i]);
616 sensitive_data.host_keys[i] = tmp;
617 if (tmp->type == KEY_RSA1)
618 sensitive_data.ssh1_host_key = tmp;
620 /* Certs do not need demotion */
623 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
627 privsep_preauth_child(void)
632 /* Enable challenge-response authentication for privilege separation */
633 privsep_challenge_enable();
636 /* Cache supported mechanism OIDs for later use */
637 if (options.gss_authentication)
638 ssh_gssapi_prepare_supported_oids();
642 arc4random_buf(rnd, sizeof(rnd));
644 RAND_seed(rnd, sizeof(rnd));
645 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
646 fatal("%s: RAND_bytes failed", __func__);
648 explicit_bzero(rnd, sizeof(rnd));
650 /* Demote the private keys to public keys. */
651 demote_sensitive_data();
653 /* Change our root directory */
654 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
655 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
657 if (chdir("/") == -1)
658 fatal("chdir(\"/\"): %s", strerror(errno));
660 /* Drop our privileges */
661 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid,
662 (u_int)privsep_pw->pw_gid);
664 /* XXX not ready, too heavy after chroot */
665 do_setusercontext(privsep_pw);
667 gidset[0] = privsep_pw->pw_gid;
668 if (setgroups(1, gidset) < 0)
669 fatal("setgroups: %.100s", strerror(errno));
670 permanently_set_uid(privsep_pw);
675 privsep_preauth(Authctxt *authctxt)
679 struct ssh_sandbox *box = NULL;
681 /* Set up unprivileged child process to deal with network data */
682 pmonitor = monitor_init();
683 /* Store a pointer to the kex for later rekeying */
684 pmonitor->m_pkex = &active_state->kex;
686 if (use_privsep == PRIVSEP_ON)
687 box = ssh_sandbox_init(pmonitor);
690 fatal("fork of unprivileged child failed");
691 } else if (pid != 0) {
692 debug2("Network child is on pid %ld", (long)pid);
694 pmonitor->m_pid = pid;
696 r = ssh_get_authentication_socket(&auth_sock);
698 error("Could not get agent socket: %s",
704 ssh_sandbox_parent_preauth(box, pid);
705 monitor_child_preauth(authctxt, pmonitor);
708 monitor_sync(pmonitor);
710 /* Wait for the child's exit status */
711 while (waitpid(pid, &status, 0) < 0) {
714 pmonitor->m_pid = -1;
715 fatal("%s: waitpid: %s", __func__, strerror(errno));
717 privsep_is_preauth = 0;
718 pmonitor->m_pid = -1;
719 if (WIFEXITED(status)) {
720 if (WEXITSTATUS(status) != 0)
721 fatal("%s: preauth child exited with status %d",
722 __func__, WEXITSTATUS(status));
723 } else if (WIFSIGNALED(status))
724 fatal("%s: preauth child terminated by signal %d",
725 __func__, WTERMSIG(status));
727 ssh_sandbox_parent_finish(box);
731 close(pmonitor->m_sendfd);
732 close(pmonitor->m_log_recvfd);
734 /* Arrange for logging to be sent to the monitor */
735 set_log_handler(mm_log_handler, pmonitor);
737 /* Demote the child */
738 if (getuid() == 0 || geteuid() == 0)
739 privsep_preauth_child();
740 setproctitle("%s", "[net]");
742 ssh_sandbox_child(box);
749 privsep_postauth(Authctxt *authctxt)
753 #ifdef DISABLE_FD_PASSING
756 if (authctxt->pw->pw_uid == 0 || options.use_login) {
758 /* File descriptor passing is broken or root login */
763 /* New socket pair */
764 monitor_reinit(pmonitor);
766 pmonitor->m_pid = fork();
767 if (pmonitor->m_pid == -1)
768 fatal("fork of unprivileged child failed");
769 else if (pmonitor->m_pid != 0) {
770 verbose("User child is on pid %ld", (long)pmonitor->m_pid);
771 buffer_clear(&loginmsg);
772 monitor_child_postauth(pmonitor);
780 close(pmonitor->m_sendfd);
781 pmonitor->m_sendfd = -1;
783 /* Demote the private keys to public keys. */
784 demote_sensitive_data();
787 arc4random_buf(rnd, sizeof(rnd));
789 RAND_seed(rnd, sizeof(rnd));
790 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
791 fatal("%s: RAND_bytes failed", __func__);
793 explicit_bzero(rnd, sizeof(rnd));
795 /* Drop privileges */
796 do_setusercontext(authctxt->pw);
799 /* It is safe now to apply the key state */
800 monitor_apply_keystate(pmonitor);
803 * Tell the packet layer that authentication was successful, since
804 * this information is not part of the key state.
806 packet_set_authenticated();
810 list_hostkey_types(void)
819 for (i = 0; i < options.num_host_key_files; i++) {
820 key = sensitive_data.host_keys[i];
822 key = sensitive_data.host_pubkeys[i];
823 if (key == NULL || key->type == KEY_RSA1)
825 /* Check that the key is accepted in HostkeyAlgorithms */
826 if (match_pattern_list(sshkey_ssh_name(key),
827 options.hostkeyalgorithms, 0) != 1) {
828 debug3("%s: %s key not permitted by HostkeyAlgorithms",
829 __func__, sshkey_ssh_name(key));
837 if (buffer_len(&b) > 0)
838 buffer_append(&b, ",", 1);
839 p = key_ssh_name(key);
840 buffer_append(&b, p, strlen(p));
843 /* If the private key has a cert peer, then list that too */
844 key = sensitive_data.host_certificates[i];
851 case KEY_ED25519_CERT:
852 if (buffer_len(&b) > 0)
853 buffer_append(&b, ",", 1);
854 p = key_ssh_name(key);
855 buffer_append(&b, p, strlen(p));
859 buffer_append(&b, "\0", 1);
860 ret = xstrdup(buffer_ptr(&b));
862 debug("list_hostkey_types: %s", ret);
867 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
872 for (i = 0; i < options.num_host_key_files; i++) {
877 case KEY_ED25519_CERT:
878 key = sensitive_data.host_certificates[i];
881 key = sensitive_data.host_keys[i];
882 if (key == NULL && !need_private)
883 key = sensitive_data.host_pubkeys[i];
886 if (key != NULL && key->type == type &&
887 (key->type != KEY_ECDSA || key->ecdsa_nid == nid))
888 return need_private ?
889 sensitive_data.host_keys[i] : key;
895 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
897 return get_hostkey_by_type(type, nid, 0, ssh);
901 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
903 return get_hostkey_by_type(type, nid, 1, ssh);
907 get_hostkey_by_index(int ind)
909 if (ind < 0 || ind >= options.num_host_key_files)
911 return (sensitive_data.host_keys[ind]);
915 get_hostkey_public_by_index(int ind, struct ssh *ssh)
917 if (ind < 0 || ind >= options.num_host_key_files)
919 return (sensitive_data.host_pubkeys[ind]);
923 get_hostkey_index(Key *key, int compare, struct ssh *ssh)
927 for (i = 0; i < options.num_host_key_files; i++) {
928 if (key_is_cert(key)) {
929 if (key == sensitive_data.host_certificates[i] ||
930 (compare && sensitive_data.host_certificates[i] &&
932 sensitive_data.host_certificates[i])))
935 if (key == sensitive_data.host_keys[i] ||
936 (compare && sensitive_data.host_keys[i] &&
937 sshkey_equal(key, sensitive_data.host_keys[i])))
939 if (key == sensitive_data.host_pubkeys[i] ||
940 (compare && sensitive_data.host_pubkeys[i] &&
941 sshkey_equal(key, sensitive_data.host_pubkeys[i])))
948 /* Inform the client of all hostkeys */
950 notify_hostkeys(struct ssh *ssh)
957 /* Some clients cannot cope with the hostkeys message, skip those. */
958 if (datafellows & SSH_BUG_HOSTKEYS)
961 if ((buf = sshbuf_new()) == NULL)
962 fatal("%s: sshbuf_new", __func__);
963 for (i = nkeys = 0; i < options.num_host_key_files; i++) {
964 key = get_hostkey_public_by_index(i, ssh);
965 if (key == NULL || key->type == KEY_UNSPEC ||
966 key->type == KEY_RSA1 || sshkey_is_cert(key))
968 fp = sshkey_fingerprint(key, options.fingerprint_hash,
970 debug3("%s: key %d: %s %s", __func__, i,
971 sshkey_ssh_name(key), fp);
974 packet_start(SSH2_MSG_GLOBAL_REQUEST);
975 packet_put_cstring("hostkeys-00@openssh.com");
976 packet_put_char(0); /* want-reply */
979 if ((r = sshkey_putb(key, buf)) != 0)
980 fatal("%s: couldn't put hostkey %d: %s",
981 __func__, i, ssh_err(r));
982 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf));
985 debug3("%s: sent %d hostkeys", __func__, nkeys);
987 fatal("%s: no hostkeys", __func__);
993 * returns 1 if connection should be dropped, 0 otherwise.
994 * dropping starts at connection #max_startups_begin with a probability
995 * of (max_startups_rate/100). the probability increases linearly until
996 * all connections are dropped for startups > max_startups
999 drop_connection(int startups)
1003 if (startups < options.max_startups_begin)
1005 if (startups >= options.max_startups)
1007 if (options.max_startups_rate == 100)
1010 p = 100 - options.max_startups_rate;
1011 p *= startups - options.max_startups_begin;
1012 p /= options.max_startups - options.max_startups_begin;
1013 p += options.max_startups_rate;
1014 r = arc4random_uniform(100);
1016 debug("drop_connection: p %d, r %d", p, r);
1017 return (r < p) ? 1 : 0;
1023 if (options.version_addendum && *options.version_addendum != '\0')
1024 fprintf(stderr, "%s %s, %s\n",
1026 options.version_addendum, OPENSSL_VERSION);
1028 fprintf(stderr, "%s, %s\n",
1029 SSH_RELEASE, OPENSSL_VERSION);
1031 "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n"
1032 " [-E log_file] [-f config_file] [-g login_grace_time]\n"
1033 " [-h host_key_file] [-k key_gen_time] [-o option] [-p port]\n"
1040 send_rexec_state(int fd, Buffer *conf)
1044 debug3("%s: entering fd = %d config len %d", __func__, fd,
1048 * Protocol from reexec master to child:
1049 * string configuration
1050 * u_int ephemeral_key_follows
1051 * bignum e (only if ephemeral_key_follows == 1)
1057 * string rngseed (only if OpenSSL is not self-seeded)
1060 buffer_put_cstring(&m, buffer_ptr(conf));
1063 if (sensitive_data.server_key != NULL &&
1064 sensitive_data.server_key->type == KEY_RSA1) {
1065 buffer_put_int(&m, 1);
1066 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
1067 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
1068 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
1069 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
1070 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
1071 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
1074 buffer_put_int(&m, 0);
1076 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
1077 rexec_send_rng_seed(&m);
1080 if (ssh_msg_send(fd, 0, &m) == -1)
1081 fatal("%s: ssh_msg_send failed", __func__);
1085 debug3("%s: done", __func__);
1089 recv_rexec_state(int fd, Buffer *conf)
1095 debug3("%s: entering fd = %d", __func__, fd);
1099 if (ssh_msg_recv(fd, &m) == -1)
1100 fatal("%s: ssh_msg_recv failed", __func__);
1101 if (buffer_get_char(&m) != 0)
1102 fatal("%s: rexec version mismatch", __func__);
1104 cp = buffer_get_string(&m, &len);
1106 buffer_append(conf, cp, len + 1);
1109 if (buffer_get_int(&m)) {
1111 if (sensitive_data.server_key != NULL)
1112 key_free(sensitive_data.server_key);
1113 sensitive_data.server_key = key_new_private(KEY_RSA1);
1114 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
1115 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
1116 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
1117 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
1118 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
1119 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
1120 if (rsa_generate_additional_parameters(
1121 sensitive_data.server_key->rsa) != 0)
1122 fatal("%s: rsa_generate_additional_parameters "
1127 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
1128 rexec_recv_rng_seed(&m);
1133 debug3("%s: done", __func__);
1136 /* Accept a connection from inetd */
1138 server_accept_inetd(int *sock_in, int *sock_out)
1144 close(REEXEC_CONFIG_PASS_FD);
1145 *sock_in = *sock_out = dup(STDIN_FILENO);
1147 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
1148 close(REEXEC_STARTUP_PIPE_FD);
1151 *sock_in = dup(STDIN_FILENO);
1152 *sock_out = dup(STDOUT_FILENO);
1155 * We intentionally do not close the descriptors 0, 1, and 2
1156 * as our code for setting the descriptors won't work if
1157 * ttyfd happens to be one of those.
1159 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1160 dup2(fd, STDIN_FILENO);
1161 dup2(fd, STDOUT_FILENO);
1163 dup2(fd, STDERR_FILENO);
1164 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO))
1167 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
1171 * Listen for TCP connections
1176 int ret, listen_sock, on = 1;
1177 struct addrinfo *ai;
1178 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1182 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1183 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1185 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1186 fatal("Too many listen sockets. "
1187 "Enlarge MAX_LISTEN_SOCKS");
1188 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
1189 ntop, sizeof(ntop), strport, sizeof(strport),
1190 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
1191 error("getnameinfo failed: %.100s",
1192 ssh_gai_strerror(ret));
1195 /* Create socket for listening. */
1196 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1198 if (listen_sock < 0) {
1199 /* kernel may not support ipv6 */
1200 verbose("socket: %.100s", strerror(errno));
1203 if (set_nonblock(listen_sock) == -1) {
1208 * Set socket options.
1209 * Allow local port reuse in TIME_WAIT.
1211 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1212 &on, sizeof(on)) == -1)
1213 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1215 /* Only communicate in IPv6 over AF_INET6 sockets. */
1216 if (ai->ai_family == AF_INET6)
1217 sock_set_v6only(listen_sock);
1219 debug("Bind to port %s on %s.", strport, ntop);
1221 len = sizeof(socksize);
1222 getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, &socksize, &len);
1223 debug("Server TCP RWIN socket size: %d", socksize);
1225 /* Bind the socket to the desired port. */
1226 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1227 error("Bind to port %s on %s failed: %.200s.",
1228 strport, ntop, strerror(errno));
1232 listen_socks[num_listen_socks] = listen_sock;
1235 /* Start listening on the port. */
1236 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1237 fatal("listen on [%s]:%s: %.100s",
1238 ntop, strport, strerror(errno));
1239 logit("Server listening on %s port %s.", ntop, strport);
1241 freeaddrinfo(options.listen_addrs);
1243 if (!num_listen_socks)
1244 fatal("Cannot bind any address.");
1248 * The main TCP accept loop. Note that, for the non-debug case, returns
1249 * from this function are in a forked subprocess.
1252 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1255 int i, j, ret, maxfd;
1256 int key_used = 0, startups = 0;
1257 int startup_p[2] = { -1 , -1 };
1258 struct sockaddr_storage from;
1263 /* setup fd set for accept */
1266 for (i = 0; i < num_listen_socks; i++)
1267 if (listen_socks[i] > maxfd)
1268 maxfd = listen_socks[i];
1269 /* pipes connected to unauthenticated childs */
1270 startup_pipes = xcalloc(options.max_startups, sizeof(int));
1271 for (i = 0; i < options.max_startups; i++)
1272 startup_pipes[i] = -1;
1275 * Stay listening for connections until the system crashes or
1276 * the daemon is killed with a signal.
1279 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 #ifdef HAVE_SECUREWARE
1503 (void)set_auth_parameters(ac, av);
1505 __progname = ssh_get_progname(av[0]);
1507 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
1510 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
1511 for (i = 0; i < ac; i++)
1512 saved_argv[i] = xstrdup(av[i]);
1513 saved_argv[i] = NULL;
1515 #ifndef HAVE_SETPROCTITLE
1516 /* Prepare for later setproctitle emulation */
1517 compat_init_setproctitle(ac, av);
1521 if (geteuid() == 0 && setgroups(0, NULL) == -1)
1522 debug("setgroups(): %.200s", strerror(errno));
1524 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1527 /* Initialize configuration options to their default values. */
1528 initialize_server_options(&options);
1530 /* Parse command-line arguments. */
1531 while ((opt = getopt(ac, av,
1532 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) {
1535 options.address_family = AF_INET;
1538 options.address_family = AF_INET6;
1541 config_file_name = optarg;
1544 if (options.num_host_cert_files >= MAX_HOSTCERTS) {
1545 fprintf(stderr, "too many host certificates.\n");
1548 options.host_cert_files[options.num_host_cert_files++] =
1549 derelativise_path(optarg);
1552 if (debug_flag == 0) {
1554 options.log_level = SYSLOG_LEVEL_DEBUG1;
1555 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1556 options.log_level++;
1562 logfile = xstrdup(optarg);
1581 options.log_level = SYSLOG_LEVEL_QUIET;
1584 options.server_key_bits = (int)strtonum(optarg, 256,
1588 options.ports_from_cmdline = 1;
1589 if (options.num_ports >= MAX_PORTS) {
1590 fprintf(stderr, "too many ports.\n");
1593 options.ports[options.num_ports++] = a2port(optarg);
1594 if (options.ports[options.num_ports-1] <= 0) {
1595 fprintf(stderr, "Bad port number.\n");
1600 if ((options.login_grace_time = convtime(optarg)) == -1) {
1601 fprintf(stderr, "Invalid login grace time.\n");
1606 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
1607 fprintf(stderr, "Invalid key regeneration interval.\n");
1612 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1613 fprintf(stderr, "too many host keys.\n");
1616 options.host_key_files[options.num_host_key_files++] =
1617 derelativise_path(optarg);
1626 if (parse_server_match_testspec(connection_info,
1631 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1632 if (utmp_len > HOST_NAME_MAX+1) {
1633 fprintf(stderr, "Invalid utmp length.\n");
1638 line = xstrdup(optarg);
1639 if (process_server_config_line(&options, line,
1640 "command-line", 0, NULL, NULL) != 0)
1650 if (rexeced_flag || inetd_flag)
1652 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
1653 fatal("sshd re-exec requires execution with an absolute path");
1655 closefrom(REEXEC_MIN_FREE_FD);
1657 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1660 OpenSSL_add_all_algorithms();
1663 /* If requested, redirect the logs to the specified logfile. */
1664 if (logfile != NULL) {
1665 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, u_int flag)
2587 u_int xxx_slen, xxx_dlen = dlen;
2590 if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen) < 0))
2591 fatal("%s: key_sign failed", __func__);
2594 } else if (use_privsep) {
2595 if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen) < 0)
2596 fatal("%s: pubkey_sign failed", __func__);
2600 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen,
2601 data, dlen, datafellows)) != 0)
2602 fatal("%s: ssh_agent_sign failed: %s",
2603 __func__, ssh_err(r));
2608 /* SSH2 key exchange */
2612 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
2616 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
2617 options.kex_algorithms);
2618 myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(
2620 myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(
2622 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2623 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2625 if (options.compression == COMP_NONE) {
2626 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2627 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
2628 } else if (options.compression == COMP_DELAYED) {
2629 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2630 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
2633 if (options.rekey_limit || options.rekey_interval)
2634 packet_set_rekey_limits((u_int32_t)options.rekey_limit,
2635 (time_t)options.rekey_interval);
2637 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
2638 list_hostkey_types());
2640 /* start key exchange */
2641 if ((r = kex_setup(active_state, myproposal)) != 0)
2642 fatal("kex_setup: %s", ssh_err(r));
2643 kex = active_state->kex;
2645 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
2646 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
2647 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
2648 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
2649 # ifdef OPENSSL_HAS_ECC
2650 kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
2653 kex->kex[KEX_C25519_SHA256] = kexc25519_server;
2655 kex->client_version_string=client_version_string;
2656 kex->server_version_string=server_version_string;
2657 kex->load_host_public_key=&get_hostkey_public_by_type;
2658 kex->load_host_private_key=&get_hostkey_private_by_type;
2659 kex->host_key_index=&get_hostkey_index;
2660 kex->sign = sshd_hostkey_sign;
2662 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state);
2664 session_id2 = kex->session_id;
2665 session_id2_len = kex->session_id_len;
2668 /* send 1st encrypted/maced/compressed message */
2669 packet_start(SSH2_MSG_IGNORE);
2670 packet_put_cstring("markus");
2672 packet_write_wait();
2677 /* server specific fatal cleanup */
2682 do_cleanup(the_authctxt);
2683 if (use_privsep && privsep_is_preauth &&
2684 pmonitor != NULL && pmonitor->m_pid > 1) {
2685 debug("Killing privsep child %d", pmonitor->m_pid);
2686 if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
2688 error("%s: kill(%d): %s", __func__,
2689 pmonitor->m_pid, strerror(errno));
2692 #ifdef SSH_AUDIT_EVENTS
2693 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2694 if (!use_privsep || mm_is_monitor())
2695 audit_event(SSH_CONNECTION_ABANDON);