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"
138 #include "blacklist_client.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 BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
394 /* Log error and exit. */
395 sigdie("Timeout before authentication for %s", get_remote_ipaddr());
399 * Signal handler for the key regeneration alarm. Note that this
400 * alarm only occurs in the daemon waiting for connections, and it does not
401 * do anything with the private key or random state before forking.
402 * Thus there should be no concurrency control/asynchronous execution
406 generate_ephemeral_server_key(void)
408 verbose("Generating %s%d bit RSA key.",
409 sensitive_data.server_key ? "new " : "", options.server_key_bits);
410 if (sensitive_data.server_key != NULL)
411 key_free(sensitive_data.server_key);
412 sensitive_data.server_key = key_generate(KEY_RSA1,
413 options.server_key_bits);
414 verbose("RSA key generation complete.");
416 arc4random_buf(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
421 key_regeneration_alarm(int sig)
423 int save_errno = errno;
425 signal(SIGALRM, SIG_DFL);
431 sshd_exchange_identification(int sock_in, int sock_out)
435 int remote_major, remote_minor;
437 char *s, *newline = "\n";
438 char buf[256]; /* Must not be larger than remote_version. */
439 char remote_version[256]; /* Must be at least as big as buf. */
441 if ((options.protocol & SSH_PROTO_1) &&
442 (options.protocol & SSH_PROTO_2)) {
443 major = PROTOCOL_MAJOR_1;
445 } else if (options.protocol & SSH_PROTO_2) {
446 major = PROTOCOL_MAJOR_2;
447 minor = PROTOCOL_MINOR_2;
450 major = PROTOCOL_MAJOR_1;
451 minor = PROTOCOL_MINOR_1;
454 xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s",
455 major, minor, SSH_VERSION,
456 *options.version_addendum == '\0' ? "" : " ",
457 options.version_addendum, newline);
459 /* Send our protocol version identification. */
460 if (atomicio(vwrite, sock_out, server_version_string,
461 strlen(server_version_string))
462 != strlen(server_version_string)) {
463 logit("Could not write ident string to %s", get_remote_ipaddr());
467 /* Read other sides version identification. */
468 memset(buf, 0, sizeof(buf));
469 for (i = 0; i < sizeof(buf) - 1; i++) {
470 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
471 logit("Did not receive identification string from %s",
472 get_remote_ipaddr());
475 if (buf[i] == '\r') {
477 /* Kludge for F-Secure Macintosh < 1.0.2 */
479 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
483 if (buf[i] == '\n') {
488 buf[sizeof(buf) - 1] = 0;
489 client_version_string = xstrdup(buf);
492 * Check that the versions match. In future this might accept
493 * several versions and set appropriate flags to handle them.
495 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
496 &remote_major, &remote_minor, remote_version) != 3) {
497 s = "Protocol mismatch.\n";
498 (void) atomicio(vwrite, sock_out, s, strlen(s));
499 logit("Bad protocol version identification '%.100s' "
500 "from %s port %d", client_version_string,
501 get_remote_ipaddr(), get_remote_port());
506 debug("Client protocol version %d.%d; client software version %.100s",
507 remote_major, remote_minor, remote_version);
509 active_state->compat = compat_datafellows(remote_version);
511 if ((datafellows & SSH_BUG_PROBE) != 0) {
512 logit("probed from %s with %s. Don't panic.",
513 get_remote_ipaddr(), client_version_string);
516 if ((datafellows & SSH_BUG_SCANNER) != 0) {
517 logit("scanned from %s with %s. Don't panic.",
518 get_remote_ipaddr(), client_version_string);
521 if ((datafellows & SSH_BUG_RSASIGMD5) != 0) {
522 logit("Client version \"%.100s\" uses unsafe RSA signature "
523 "scheme; disabling use of RSA keys", remote_version);
525 if ((datafellows & SSH_BUG_DERIVEKEY) != 0) {
526 fatal("Client version \"%.100s\" uses unsafe key agreement; "
527 "refusing connection", remote_version);
531 switch (remote_major) {
533 if (remote_minor == 99) {
534 if (options.protocol & SSH_PROTO_2)
540 if (!(options.protocol & SSH_PROTO_1)) {
544 if (remote_minor < 3) {
545 packet_disconnect("Your ssh version is too old and "
546 "is no longer supported. Please install a newer version.");
547 } else if (remote_minor == 3) {
548 /* note that this disables agent-forwarding */
553 if (options.protocol & SSH_PROTO_2) {
562 chop(server_version_string);
563 debug("Local version string %.200s", server_version_string);
566 s = "Protocol major versions differ.\n";
567 (void) atomicio(vwrite, sock_out, s, strlen(s));
570 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
572 server_version_string, client_version_string);
577 /* Destroy the host and server keys. They will no longer be needed. */
579 destroy_sensitive_data(void)
583 if (sensitive_data.server_key) {
584 key_free(sensitive_data.server_key);
585 sensitive_data.server_key = NULL;
587 for (i = 0; i < options.num_host_key_files; i++) {
588 if (sensitive_data.host_keys[i]) {
589 key_free(sensitive_data.host_keys[i]);
590 sensitive_data.host_keys[i] = NULL;
592 if (sensitive_data.host_certificates[i]) {
593 key_free(sensitive_data.host_certificates[i]);
594 sensitive_data.host_certificates[i] = NULL;
597 sensitive_data.ssh1_host_key = NULL;
598 explicit_bzero(sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
601 /* Demote private to public keys for network child */
603 demote_sensitive_data(void)
608 if (sensitive_data.server_key) {
609 tmp = key_demote(sensitive_data.server_key);
610 key_free(sensitive_data.server_key);
611 sensitive_data.server_key = tmp;
614 for (i = 0; i < options.num_host_key_files; i++) {
615 if (sensitive_data.host_keys[i]) {
616 tmp = key_demote(sensitive_data.host_keys[i]);
617 key_free(sensitive_data.host_keys[i]);
618 sensitive_data.host_keys[i] = tmp;
619 if (tmp->type == KEY_RSA1)
620 sensitive_data.ssh1_host_key = tmp;
622 /* Certs do not need demotion */
625 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
629 privsep_preauth_child(void)
634 /* Enable challenge-response authentication for privilege separation */
635 privsep_challenge_enable();
638 /* Cache supported mechanism OIDs for later use */
639 if (options.gss_authentication)
640 ssh_gssapi_prepare_supported_oids();
644 arc4random_buf(rnd, sizeof(rnd));
646 RAND_seed(rnd, sizeof(rnd));
647 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
648 fatal("%s: RAND_bytes failed", __func__);
650 explicit_bzero(rnd, sizeof(rnd));
652 /* Demote the private keys to public keys. */
653 demote_sensitive_data();
655 /* Demote the child */
656 if (getuid() == 0 || geteuid() == 0) {
657 /* Change our root directory */
658 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
659 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
661 if (chdir("/") == -1)
662 fatal("chdir(\"/\"): %s", strerror(errno));
664 /* Drop our privileges */
665 debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid,
666 (u_int)privsep_pw->pw_gid);
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 privsep_preauth_child();
738 setproctitle("%s", "[net]");
740 ssh_sandbox_child(box);
747 privsep_postauth(Authctxt *authctxt)
751 #ifdef DISABLE_FD_PASSING
754 if (authctxt->pw->pw_uid == 0 || options.use_login) {
756 /* File descriptor passing is broken or root login */
761 /* New socket pair */
762 monitor_reinit(pmonitor);
764 pmonitor->m_pid = fork();
765 if (pmonitor->m_pid == -1)
766 fatal("fork of unprivileged child failed");
767 else if (pmonitor->m_pid != 0) {
768 verbose("User child is on pid %ld", (long)pmonitor->m_pid);
769 buffer_clear(&loginmsg);
770 monitor_child_postauth(pmonitor);
778 close(pmonitor->m_sendfd);
779 pmonitor->m_sendfd = -1;
781 /* Demote the private keys to public keys. */
782 demote_sensitive_data();
785 arc4random_buf(rnd, sizeof(rnd));
787 RAND_seed(rnd, sizeof(rnd));
788 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
789 fatal("%s: RAND_bytes failed", __func__);
791 explicit_bzero(rnd, sizeof(rnd));
793 /* Drop privileges */
794 do_setusercontext(authctxt->pw);
797 /* It is safe now to apply the key state */
798 monitor_apply_keystate(pmonitor);
801 * Tell the packet layer that authentication was successful, since
802 * this information is not part of the key state.
804 packet_set_authenticated();
808 list_hostkey_types(void)
817 for (i = 0; i < options.num_host_key_files; i++) {
818 key = sensitive_data.host_keys[i];
820 key = sensitive_data.host_pubkeys[i];
821 if (key == NULL || key->type == KEY_RSA1)
823 /* Check that the key is accepted in HostkeyAlgorithms */
824 if (match_pattern_list(sshkey_ssh_name(key),
825 options.hostkeyalgorithms, 0) != 1) {
826 debug3("%s: %s key not permitted by HostkeyAlgorithms",
827 __func__, sshkey_ssh_name(key));
835 if (buffer_len(&b) > 0)
836 buffer_append(&b, ",", 1);
837 p = key_ssh_name(key);
838 buffer_append(&b, p, strlen(p));
840 /* for RSA we also support SHA2 signatures */
841 if (key->type == KEY_RSA) {
842 p = ",rsa-sha2-512,rsa-sha2-256";
843 buffer_append(&b, p, strlen(p));
847 /* If the private key has a cert peer, then list that too */
848 key = sensitive_data.host_certificates[i];
855 case KEY_ED25519_CERT:
856 if (buffer_len(&b) > 0)
857 buffer_append(&b, ",", 1);
858 p = key_ssh_name(key);
859 buffer_append(&b, p, strlen(p));
863 buffer_append(&b, "\0", 1);
864 ret = xstrdup(buffer_ptr(&b));
866 debug("list_hostkey_types: %s", ret);
871 get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
876 for (i = 0; i < options.num_host_key_files; i++) {
881 case KEY_ED25519_CERT:
882 key = sensitive_data.host_certificates[i];
885 key = sensitive_data.host_keys[i];
886 if (key == NULL && !need_private)
887 key = sensitive_data.host_pubkeys[i];
890 if (key != NULL && key->type == type &&
891 (key->type != KEY_ECDSA || key->ecdsa_nid == nid))
892 return need_private ?
893 sensitive_data.host_keys[i] : key;
899 get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
901 return get_hostkey_by_type(type, nid, 0, ssh);
905 get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
907 return get_hostkey_by_type(type, nid, 1, ssh);
911 get_hostkey_by_index(int ind)
913 if (ind < 0 || ind >= options.num_host_key_files)
915 return (sensitive_data.host_keys[ind]);
919 get_hostkey_public_by_index(int ind, struct ssh *ssh)
921 if (ind < 0 || ind >= options.num_host_key_files)
923 return (sensitive_data.host_pubkeys[ind]);
927 get_hostkey_index(Key *key, int compare, struct ssh *ssh)
931 for (i = 0; i < options.num_host_key_files; i++) {
932 if (key_is_cert(key)) {
933 if (key == sensitive_data.host_certificates[i] ||
934 (compare && sensitive_data.host_certificates[i] &&
936 sensitive_data.host_certificates[i])))
939 if (key == sensitive_data.host_keys[i] ||
940 (compare && sensitive_data.host_keys[i] &&
941 sshkey_equal(key, sensitive_data.host_keys[i])))
943 if (key == sensitive_data.host_pubkeys[i] ||
944 (compare && sensitive_data.host_pubkeys[i] &&
945 sshkey_equal(key, sensitive_data.host_pubkeys[i])))
952 /* Inform the client of all hostkeys */
954 notify_hostkeys(struct ssh *ssh)
961 /* Some clients cannot cope with the hostkeys message, skip those. */
962 if (datafellows & SSH_BUG_HOSTKEYS)
965 if ((buf = sshbuf_new()) == NULL)
966 fatal("%s: sshbuf_new", __func__);
967 for (i = nkeys = 0; i < options.num_host_key_files; i++) {
968 key = get_hostkey_public_by_index(i, ssh);
969 if (key == NULL || key->type == KEY_UNSPEC ||
970 key->type == KEY_RSA1 || sshkey_is_cert(key))
972 fp = sshkey_fingerprint(key, options.fingerprint_hash,
974 debug3("%s: key %d: %s %s", __func__, i,
975 sshkey_ssh_name(key), fp);
978 packet_start(SSH2_MSG_GLOBAL_REQUEST);
979 packet_put_cstring("hostkeys-00@openssh.com");
980 packet_put_char(0); /* want-reply */
983 if ((r = sshkey_putb(key, buf)) != 0)
984 fatal("%s: couldn't put hostkey %d: %s",
985 __func__, i, ssh_err(r));
986 packet_put_string(sshbuf_ptr(buf), sshbuf_len(buf));
989 debug3("%s: sent %d hostkeys", __func__, nkeys);
991 fatal("%s: no hostkeys", __func__);
997 * returns 1 if connection should be dropped, 0 otherwise.
998 * dropping starts at connection #max_startups_begin with a probability
999 * of (max_startups_rate/100). the probability increases linearly until
1000 * all connections are dropped for startups > max_startups
1003 drop_connection(int startups)
1007 if (startups < options.max_startups_begin)
1009 if (startups >= options.max_startups)
1011 if (options.max_startups_rate == 100)
1014 p = 100 - options.max_startups_rate;
1015 p *= startups - options.max_startups_begin;
1016 p /= options.max_startups - options.max_startups_begin;
1017 p += options.max_startups_rate;
1018 r = arc4random_uniform(100);
1020 debug("drop_connection: p %d, r %d", p, r);
1021 return (r < p) ? 1 : 0;
1027 if (options.version_addendum && *options.version_addendum != '\0')
1028 fprintf(stderr, "%s %s, %s\n",
1030 options.version_addendum, OPENSSL_VERSION);
1032 fprintf(stderr, "%s, %s\n",
1033 SSH_RELEASE, OPENSSL_VERSION);
1035 "usage: sshd [-46DdeiqTt] [-b bits] [-C connection_spec] [-c host_cert_file]\n"
1036 " [-E log_file] [-f config_file] [-g login_grace_time]\n"
1037 " [-h host_key_file] [-k key_gen_time] [-o option] [-p port]\n"
1044 send_rexec_state(int fd, Buffer *conf)
1048 debug3("%s: entering fd = %d config len %d", __func__, fd,
1052 * Protocol from reexec master to child:
1053 * string configuration
1054 * u_int ephemeral_key_follows
1055 * bignum e (only if ephemeral_key_follows == 1)
1061 * string rngseed (only if OpenSSL is not self-seeded)
1064 buffer_put_cstring(&m, buffer_ptr(conf));
1067 if (sensitive_data.server_key != NULL &&
1068 sensitive_data.server_key->type == KEY_RSA1) {
1069 buffer_put_int(&m, 1);
1070 buffer_put_bignum(&m, sensitive_data.server_key->rsa->e);
1071 buffer_put_bignum(&m, sensitive_data.server_key->rsa->n);
1072 buffer_put_bignum(&m, sensitive_data.server_key->rsa->d);
1073 buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp);
1074 buffer_put_bignum(&m, sensitive_data.server_key->rsa->p);
1075 buffer_put_bignum(&m, sensitive_data.server_key->rsa->q);
1078 buffer_put_int(&m, 0);
1080 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
1081 rexec_send_rng_seed(&m);
1084 if (ssh_msg_send(fd, 0, &m) == -1)
1085 fatal("%s: ssh_msg_send failed", __func__);
1089 debug3("%s: done", __func__);
1093 recv_rexec_state(int fd, Buffer *conf)
1099 debug3("%s: entering fd = %d", __func__, fd);
1103 if (ssh_msg_recv(fd, &m) == -1)
1104 fatal("%s: ssh_msg_recv failed", __func__);
1105 if (buffer_get_char(&m) != 0)
1106 fatal("%s: rexec version mismatch", __func__);
1108 cp = buffer_get_string(&m, &len);
1110 buffer_append(conf, cp, len + 1);
1113 if (buffer_get_int(&m)) {
1115 if (sensitive_data.server_key != NULL)
1116 key_free(sensitive_data.server_key);
1117 sensitive_data.server_key = key_new_private(KEY_RSA1);
1118 buffer_get_bignum(&m, sensitive_data.server_key->rsa->e);
1119 buffer_get_bignum(&m, sensitive_data.server_key->rsa->n);
1120 buffer_get_bignum(&m, sensitive_data.server_key->rsa->d);
1121 buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp);
1122 buffer_get_bignum(&m, sensitive_data.server_key->rsa->p);
1123 buffer_get_bignum(&m, sensitive_data.server_key->rsa->q);
1124 if (rsa_generate_additional_parameters(
1125 sensitive_data.server_key->rsa) != 0)
1126 fatal("%s: rsa_generate_additional_parameters "
1131 #if defined(WITH_OPENSSL) && !defined(OPENSSL_PRNG_ONLY)
1132 rexec_recv_rng_seed(&m);
1137 debug3("%s: done", __func__);
1140 /* Accept a connection from inetd */
1142 server_accept_inetd(int *sock_in, int *sock_out)
1148 close(REEXEC_CONFIG_PASS_FD);
1149 *sock_in = *sock_out = dup(STDIN_FILENO);
1151 startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
1152 close(REEXEC_STARTUP_PIPE_FD);
1155 *sock_in = dup(STDIN_FILENO);
1156 *sock_out = dup(STDOUT_FILENO);
1159 * We intentionally do not close the descriptors 0, 1, and 2
1160 * as our code for setting the descriptors won't work if
1161 * ttyfd happens to be one of those.
1163 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
1164 dup2(fd, STDIN_FILENO);
1165 dup2(fd, STDOUT_FILENO);
1167 dup2(fd, STDERR_FILENO);
1168 if (fd > (log_stderr ? STDERR_FILENO : STDOUT_FILENO))
1171 debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
1175 * Listen for TCP connections
1180 int ret, listen_sock, on = 1;
1181 struct addrinfo *ai;
1182 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
1186 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1187 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1189 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1190 fatal("Too many listen sockets. "
1191 "Enlarge MAX_LISTEN_SOCKS");
1192 if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
1193 ntop, sizeof(ntop), strport, sizeof(strport),
1194 NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
1195 error("getnameinfo failed: %.100s",
1196 ssh_gai_strerror(ret));
1199 /* Create socket for listening. */
1200 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1202 if (listen_sock < 0) {
1203 /* kernel may not support ipv6 */
1204 verbose("socket: %.100s", strerror(errno));
1207 if (set_nonblock(listen_sock) == -1) {
1212 * Set socket options.
1213 * Allow local port reuse in TIME_WAIT.
1215 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1216 &on, sizeof(on)) == -1)
1217 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1219 /* Only communicate in IPv6 over AF_INET6 sockets. */
1220 if (ai->ai_family == AF_INET6)
1221 sock_set_v6only(listen_sock);
1223 debug("Bind to port %s on %s.", strport, ntop);
1225 len = sizeof(socksize);
1226 getsockopt(listen_sock, SOL_SOCKET, SO_RCVBUF, &socksize, &len);
1227 debug("Server TCP RWIN socket size: %d", socksize);
1229 /* Bind the socket to the desired port. */
1230 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1231 error("Bind to port %s on %s failed: %.200s.",
1232 strport, ntop, strerror(errno));
1236 listen_socks[num_listen_socks] = listen_sock;
1239 /* Start listening on the port. */
1240 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1241 fatal("listen on [%s]:%s: %.100s",
1242 ntop, strport, strerror(errno));
1243 logit("Server listening on %s port %s.", ntop, strport);
1245 freeaddrinfo(options.listen_addrs);
1247 if (!num_listen_socks)
1248 fatal("Cannot bind any address.");
1252 * The main TCP accept loop. Note that, for the non-debug case, returns
1253 * from this function are in a forked subprocess.
1256 server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
1259 int i, j, ret, maxfd;
1260 int key_used = 0, startups = 0;
1261 int startup_p[2] = { -1 , -1 };
1262 struct sockaddr_storage from;
1267 /* setup fd set for accept */
1270 for (i = 0; i < num_listen_socks; i++)
1271 if (listen_socks[i] > maxfd)
1272 maxfd = listen_socks[i];
1273 /* pipes connected to unauthenticated childs */
1274 startup_pipes = xcalloc(options.max_startups, sizeof(int));
1275 for (i = 0; i < options.max_startups; i++)
1276 startup_pipes[i] = -1;
1279 * Stay listening for connections until the system crashes or
1280 * the daemon is killed with a signal.
1283 if (received_sighup)
1286 fdset = xcalloc(howmany(maxfd + 1, NFDBITS),
1289 for (i = 0; i < num_listen_socks; i++)
1290 FD_SET(listen_socks[i], fdset);
1291 for (i = 0; i < options.max_startups; i++)
1292 if (startup_pipes[i] != -1)
1293 FD_SET(startup_pipes[i], fdset);
1295 /* Wait in select until there is a connection. */
1296 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1297 if (ret < 0 && errno != EINTR)
1298 error("select: %.100s", strerror(errno));
1299 if (received_sigterm) {
1300 logit("Received signal %d; terminating.",
1301 (int) received_sigterm);
1302 close_listen_socks();
1303 if (options.pid_file != NULL)
1304 unlink(options.pid_file);
1305 exit(received_sigterm == SIGTERM ? 0 : 255);
1307 if (key_used && key_do_regen) {
1308 generate_ephemeral_server_key();
1315 for (i = 0; i < options.max_startups; i++)
1316 if (startup_pipes[i] != -1 &&
1317 FD_ISSET(startup_pipes[i], fdset)) {
1319 * the read end of the pipe is ready
1320 * if the child has closed the pipe
1321 * after successful authentication
1322 * or if the child has died
1324 close(startup_pipes[i]);
1325 startup_pipes[i] = -1;
1328 for (i = 0; i < num_listen_socks; i++) {
1329 if (!FD_ISSET(listen_socks[i], fdset))
1331 fromlen = sizeof(from);
1332 *newsock = accept(listen_socks[i],
1333 (struct sockaddr *)&from, &fromlen);
1335 if (errno != EINTR && errno != EWOULDBLOCK &&
1336 errno != ECONNABORTED && errno != EAGAIN)
1337 error("accept: %.100s",
1339 if (errno == EMFILE || errno == ENFILE)
1343 if (unset_nonblock(*newsock) == -1) {
1347 if (drop_connection(startups) == 1) {
1348 debug("drop connection #%d", startups);
1352 if (pipe(startup_p) == -1) {
1357 if (rexec_flag && socketpair(AF_UNIX,
1358 SOCK_STREAM, 0, config_s) == -1) {
1359 error("reexec socketpair: %s",
1362 close(startup_p[0]);
1363 close(startup_p[1]);
1367 for (j = 0; j < options.max_startups; j++)
1368 if (startup_pipes[j] == -1) {
1369 startup_pipes[j] = startup_p[0];
1370 if (maxfd < startup_p[0])
1371 maxfd = startup_p[0];
1377 * Got connection. Fork a child to handle it, unless
1378 * we are in debugging mode.
1382 * In debugging mode. Close the listening
1383 * socket, and start processing the
1384 * connection without forking.
1386 debug("Server will not fork when running in debugging mode.");
1387 close_listen_socks();
1388 *sock_in = *newsock;
1389 *sock_out = *newsock;
1390 close(startup_p[0]);
1391 close(startup_p[1]);
1395 send_rexec_state(config_s[0],
1403 * Normal production daemon. Fork, and have
1404 * the child process the connection. The
1405 * parent continues listening.
1407 platform_pre_fork();
1408 if ((pid = fork()) == 0) {
1410 * Child. Close the listening and
1411 * max_startup sockets. Start using
1412 * the accepted socket. Reinitialize
1413 * logging (since our pid has changed).
1414 * We break out of the loop to handle
1417 platform_post_fork_child();
1418 startup_pipe = startup_p[1];
1419 close_startup_pipes();
1420 close_listen_socks();
1421 *sock_in = *newsock;
1422 *sock_out = *newsock;
1423 log_init(__progname,
1425 options.log_facility,
1432 /* Parent. Stay in the loop. */
1433 platform_post_fork_parent(pid);
1435 error("fork: %.100s", strerror(errno));
1437 debug("Forked child %ld.", (long)pid);
1439 close(startup_p[1]);
1442 send_rexec_state(config_s[0], &cfg);
1448 * Mark that the key has been used (it
1449 * was "given" to the child).
1451 if ((options.protocol & SSH_PROTO_1) &&
1453 /* Schedule server key regeneration alarm. */
1454 signal(SIGALRM, key_regeneration_alarm);
1455 alarm(options.key_regeneration_time);
1462 * Ensure that our random state differs
1463 * from that of the child
1466 arc4random_buf(rnd, sizeof(rnd));
1468 RAND_seed(rnd, sizeof(rnd));
1469 if ((RAND_bytes((u_char *)rnd, 1)) != 1)
1470 fatal("%s: RAND_bytes failed", __func__);
1472 explicit_bzero(rnd, sizeof(rnd));
1475 /* child process check (or debug mode) */
1476 if (num_listen_socks < 0)
1483 * Main program for the daemon.
1486 main(int ac, char **av)
1488 extern char *optarg;
1490 int r, opt, i, j, on = 1;
1491 int sock_in = -1, sock_out = -1, newsock = -1;
1492 const char *remote_ip;
1494 char *fp, *line, *laddr, *logfile = NULL;
1495 int config_s[2] = { -1 , -1 };
1497 u_int64_t ibytes, obytes;
1503 struct connection_info *connection_info = get_connection_info(0, 0);
1505 ssh_malloc_init(); /* must be called before any mallocs */
1507 #ifdef HAVE_SECUREWARE
1508 (void)set_auth_parameters(ac, av);
1510 __progname = ssh_get_progname(av[0]);
1512 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
1515 saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
1516 for (i = 0; i < ac; i++)
1517 saved_argv[i] = xstrdup(av[i]);
1518 saved_argv[i] = NULL;
1520 #ifndef HAVE_SETPROCTITLE
1521 /* Prepare for later setproctitle emulation */
1522 compat_init_setproctitle(ac, av);
1526 if (geteuid() == 0 && setgroups(0, NULL) == -1)
1527 debug("setgroups(): %.200s", strerror(errno));
1529 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
1532 /* Initialize configuration options to their default values. */
1533 initialize_server_options(&options);
1535 /* Parse command-line arguments. */
1536 while ((opt = getopt(ac, av,
1537 "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrt")) != -1) {
1540 options.address_family = AF_INET;
1543 options.address_family = AF_INET6;
1546 config_file_name = optarg;
1549 if (options.num_host_cert_files >= MAX_HOSTCERTS) {
1550 fprintf(stderr, "too many host certificates.\n");
1553 options.host_cert_files[options.num_host_cert_files++] =
1554 derelativise_path(optarg);
1557 if (debug_flag == 0) {
1559 options.log_level = SYSLOG_LEVEL_DEBUG1;
1560 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
1561 options.log_level++;
1586 options.log_level = SYSLOG_LEVEL_QUIET;
1589 options.server_key_bits = (int)strtonum(optarg, 256,
1593 options.ports_from_cmdline = 1;
1594 if (options.num_ports >= MAX_PORTS) {
1595 fprintf(stderr, "too many ports.\n");
1598 options.ports[options.num_ports++] = a2port(optarg);
1599 if (options.ports[options.num_ports-1] <= 0) {
1600 fprintf(stderr, "Bad port number.\n");
1605 if ((options.login_grace_time = convtime(optarg)) == -1) {
1606 fprintf(stderr, "Invalid login grace time.\n");
1611 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
1612 fprintf(stderr, "Invalid key regeneration interval.\n");
1617 if (options.num_host_key_files >= MAX_HOSTKEYS) {
1618 fprintf(stderr, "too many host keys.\n");
1621 options.host_key_files[options.num_host_key_files++] =
1622 derelativise_path(optarg);
1631 if (parse_server_match_testspec(connection_info,
1636 utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
1637 if (utmp_len > HOST_NAME_MAX+1) {
1638 fprintf(stderr, "Invalid utmp length.\n");
1643 line = xstrdup(optarg);
1644 if (process_server_config_line(&options, line,
1645 "command-line", 0, NULL, NULL) != 0)
1655 if (rexeced_flag || inetd_flag)
1657 if (!test_flag && (rexec_flag && (av[0] == NULL || *av[0] != '/')))
1658 fatal("sshd re-exec requires execution with an absolute path");
1660 closefrom(REEXEC_MIN_FREE_FD);
1662 closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
1665 OpenSSL_add_all_algorithms();
1668 /* If requested, redirect the logs to the specified logfile. */
1669 if (logfile != NULL)
1670 log_redirect_stderr_to(logfile);
1672 * Force logging to stderr until we have loaded the private host
1673 * key (unless started from inetd)
1675 log_init(__progname,
1676 options.log_level == SYSLOG_LEVEL_NOT_SET ?
1677 SYSLOG_LEVEL_INFO : options.log_level,
1678 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
1679 SYSLOG_FACILITY_AUTH : options.log_facility,
1680 log_stderr || !inetd_flag);
1683 * Unset KRB5CCNAME, otherwise the user's session may inherit it from
1684 * root's environment
1686 if (getenv("KRB5CCNAME") != NULL)
1687 (void) unsetenv("KRB5CCNAME");
1690 /* Cray can define user privs drop all privs now!
1691 * Not needed on PRIV_SU systems!
1696 sensitive_data.server_key = NULL;
1697 sensitive_data.ssh1_host_key = NULL;
1698 sensitive_data.have_ssh1_key = 0;
1699 sensitive_data.have_ssh2_key = 0;
1702 * If we're doing an extended config test, make sure we have all of
1703 * the parameters we need. If we're not doing an extended test,
1704 * do not silently ignore connection test params.
1706 if (test_flag >= 2 && server_match_spec_complete(connection_info) == 0)
1707 fatal("user, host and addr are all required when testing "
1709 if (test_flag < 2 && server_match_spec_complete(connection_info) >= 0)
1710 fatal("Config test connection parameter (-C) provided without "
1713 /* Fetch our configuration */
1716 recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg);
1717 else if (strcasecmp(config_file_name, "none") != 0)
1718 load_server_config(config_file_name, &cfg);
1720 parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
1725 /* Fill in default values for those options not explicitly set. */
1726 fill_default_server_options(&options);
1728 /* challenge-response is implemented via keyboard interactive */
1729 if (options.challenge_response_authentication)
1730 options.kbd_interactive_authentication = 1;
1732 /* Check that options are sensible */
1733 if (options.authorized_keys_command_user == NULL &&
1734 (options.authorized_keys_command != NULL &&
1735 strcasecmp(options.authorized_keys_command, "none") != 0))
1736 fatal("AuthorizedKeysCommand set without "
1737 "AuthorizedKeysCommandUser");
1738 if (options.authorized_principals_command_user == NULL &&
1739 (options.authorized_principals_command != NULL &&
1740 strcasecmp(options.authorized_principals_command, "none") != 0))
1741 fatal("AuthorizedPrincipalsCommand set without "
1742 "AuthorizedPrincipalsCommandUser");
1745 * Check whether there is any path through configured auth methods.
1746 * Unfortunately it is not possible to verify this generally before
1747 * daemonisation in the presence of Match block, but this catches
1748 * and warns for trivial misconfigurations that could break login.
1750 if (options.num_auth_methods != 0) {
1751 if ((options.protocol & SSH_PROTO_1))
1752 fatal("AuthenticationMethods is not supported with "
1754 for (n = 0; n < options.num_auth_methods; n++) {
1755 if (auth2_methods_valid(options.auth_methods[n],
1759 if (n >= options.num_auth_methods)
1760 fatal("AuthenticationMethods cannot be satisfied by "
1761 "enabled authentication methods");
1764 /* set default channel AF */
1765 channel_set_af(options.address_family);
1767 /* Check that there are no remaining arguments. */
1769 fprintf(stderr, "Extra argument %s.\n", av[optind]);
1773 debug("sshd version %s, %s", SSH_VERSION,
1775 SSLeay_version(SSLEAY_VERSION)
1781 /* Store privilege separation user for later use if required. */
1782 if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
1783 if (use_privsep || options.kerberos_authentication)
1784 fatal("Privilege separation user %s does not exist",
1787 explicit_bzero(privsep_pw->pw_passwd,
1788 strlen(privsep_pw->pw_passwd));
1789 privsep_pw = pwcopy(privsep_pw);
1790 free(privsep_pw->pw_passwd);
1791 privsep_pw->pw_passwd = xstrdup("*");
1795 /* load host keys */
1796 sensitive_data.host_keys = xcalloc(options.num_host_key_files,
1798 sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
1801 if (options.host_key_agent) {
1802 if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
1803 setenv(SSH_AUTHSOCKET_ENV_NAME,
1804 options.host_key_agent, 1);
1805 if ((r = ssh_get_authentication_socket(NULL)) == 0)
1808 error("Could not connect to agent \"%s\": %s",
1809 options.host_key_agent, ssh_err(r));
1812 for (i = 0; i < options.num_host_key_files; i++) {
1813 if (options.host_key_files[i] == NULL)
1815 key = key_load_private(options.host_key_files[i], "", NULL);
1816 pubkey = key_load_public(options.host_key_files[i], NULL);
1817 if (pubkey == NULL && key != NULL)
1818 pubkey = key_demote(key);
1819 sensitive_data.host_keys[i] = key;
1820 sensitive_data.host_pubkeys[i] = pubkey;
1822 if (key == NULL && pubkey != NULL && pubkey->type != KEY_RSA1 &&
1824 debug("will rely on agent for hostkey %s",
1825 options.host_key_files[i]);
1826 keytype = pubkey->type;
1827 } else if (key != NULL) {
1828 keytype = key->type;
1830 error("Could not load host key: %s",
1831 options.host_key_files[i]);
1832 sensitive_data.host_keys[i] = NULL;
1833 sensitive_data.host_pubkeys[i] = NULL;
1839 sensitive_data.ssh1_host_key = key;
1840 sensitive_data.have_ssh1_key = 1;
1846 if (have_agent || key != NULL)
1847 sensitive_data.have_ssh2_key = 1;
1850 if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash,
1851 SSH_FP_DEFAULT)) == NULL)
1852 fatal("sshkey_fingerprint failed");
1853 debug("%s host key #%d: %s %s",
1854 key ? "private" : "agent", i, keytype == KEY_RSA1 ?
1855 sshkey_type(pubkey) : sshkey_ssh_name(pubkey), fp);
1858 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
1859 logit("Disabling protocol version 1. Could not load host key");
1860 options.protocol &= ~SSH_PROTO_1;
1862 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1863 logit("Disabling protocol version 2. Could not load host key");
1864 options.protocol &= ~SSH_PROTO_2;
1866 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1867 logit("sshd: no hostkeys available -- exiting.");
1872 * Load certificates. They are stored in an array at identical
1873 * indices to the public keys that they relate to.
1875 sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
1877 for (i = 0; i < options.num_host_key_files; i++)
1878 sensitive_data.host_certificates[i] = NULL;
1880 for (i = 0; i < options.num_host_cert_files; i++) {
1881 if (options.host_cert_files[i] == NULL)
1883 key = key_load_public(options.host_cert_files[i], NULL);
1885 error("Could not load host certificate: %s",
1886 options.host_cert_files[i]);
1889 if (!key_is_cert(key)) {
1890 error("Certificate file is not a certificate: %s",
1891 options.host_cert_files[i]);
1895 /* Find matching private key */
1896 for (j = 0; j < options.num_host_key_files; j++) {
1897 if (key_equal_public(key,
1898 sensitive_data.host_keys[j])) {
1899 sensitive_data.host_certificates[j] = key;
1903 if (j >= options.num_host_key_files) {
1904 error("No matching private key for certificate: %s",
1905 options.host_cert_files[i]);
1909 sensitive_data.host_certificates[j] = key;
1910 debug("host certificate: #%d type %d %s", j, key->type,
1915 /* Check certain values for sanity. */
1916 if (options.protocol & SSH_PROTO_1) {
1917 if (options.server_key_bits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
1918 options.server_key_bits > OPENSSL_RSA_MAX_MODULUS_BITS) {
1919 fprintf(stderr, "Bad server key size.\n");
1923 * Check that server and host key lengths differ sufficiently. This
1924 * is necessary to make double encryption work with rsaref. Oh, I
1925 * hate software patents. I dont know if this can go? Niels
1927 if (options.server_key_bits >
1928 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1929 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1930 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1931 SSH_KEY_BITS_RESERVED) {
1932 options.server_key_bits =
1933 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1934 SSH_KEY_BITS_RESERVED;
1935 debug("Forcing server key to %d bits to make it differ from host key.",
1936 options.server_key_bits);
1944 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1945 (S_ISDIR(st.st_mode) == 0))
1946 fatal("Missing privilege separation directory: %s",
1947 _PATH_PRIVSEP_CHROOT_DIR);
1950 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1951 (st.st_uid != getuid () ||
1952 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1954 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1956 fatal("%s must be owned by root and not group or "
1957 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1960 if (test_flag > 1) {
1961 if (server_match_spec_complete(connection_info) == 1)
1962 parse_server_match_config(&options, connection_info);
1963 dump_config(&options);
1966 /* Configuration looks good, so exit if in test mode. */
1971 * Clear out any supplemental groups we may have inherited. This
1972 * prevents inadvertent creation of files with bad modes (in the
1973 * portable version at least, it's certainly possible for PAM
1974 * to create a file, and we can't control the code in every
1975 * module which might be used).
1977 if (setgroups(0, NULL) < 0)
1978 debug("setgroups() failed: %.200s", strerror(errno));
1981 rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
1982 for (i = 0; i < rexec_argc; i++) {
1983 debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
1984 rexec_argv[i] = saved_argv[i];
1986 rexec_argv[rexec_argc] = "-R";
1987 rexec_argv[rexec_argc + 1] = NULL;
1990 /* Ensure that umask disallows at least group and world write */
1991 new_umask = umask(0077) | 0022;
1992 (void) umask(new_umask);
1994 /* Initialize the log (it is reinitialized below in case we forked). */
1995 if (debug_flag && (!inetd_flag || rexeced_flag))
1997 log_init(__progname, options.log_level, options.log_facility, log_stderr);
2000 * If not in debugging mode, and not started from inetd, disconnect
2001 * from the controlling terminal, and fork. The original process
2004 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
2007 #endif /* TIOCNOTTY */
2008 if (daemon(0, 0) < 0)
2009 fatal("daemon() failed: %.200s", strerror(errno));
2011 /* Disconnect from the controlling tty. */
2013 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
2015 (void) ioctl(fd, TIOCNOTTY, NULL);
2018 #endif /* TIOCNOTTY */
2020 /* Reinitialize the log (because of the fork above). */
2021 log_init(__progname, options.log_level, options.log_facility, log_stderr);
2023 /* Avoid killing the process in high-pressure swapping environments. */
2024 if (!inetd_flag && madvise(NULL, 0, MADV_PROTECT) != 0)
2025 debug("madvise(): %.200s", strerror(errno));
2027 /* Chdir to the root directory so that the current disk can be
2028 unmounted if desired. */
2029 if (chdir("/") == -1)
2030 error("chdir(\"/\"): %s", strerror(errno));
2032 /* ignore SIGPIPE */
2033 signal(SIGPIPE, SIG_IGN);
2035 /* Get a connection, either from inetd or a listening TCP socket */
2037 server_accept_inetd(&sock_in, &sock_out);
2039 platform_pre_listen();
2042 if (options.protocol & SSH_PROTO_1)
2043 generate_ephemeral_server_key();
2045 signal(SIGHUP, sighup_handler);
2046 signal(SIGCHLD, main_sigchld_handler);
2047 signal(SIGTERM, sigterm_handler);
2048 signal(SIGQUIT, sigterm_handler);
2051 * Write out the pid file after the sigterm handler
2052 * is setup and the listen sockets are bound
2054 if (options.pid_file != NULL && !debug_flag) {
2055 FILE *f = fopen(options.pid_file, "w");
2058 error("Couldn't create pid file \"%s\": %s",
2059 options.pid_file, strerror(errno));
2061 fprintf(f, "%ld\n", (long) getpid());
2066 /* Accept a connection and return in a forked child */
2067 server_accept_loop(&sock_in, &sock_out,
2068 &newsock, config_s);
2071 /* This is the child processing a new connection. */
2072 setproctitle("%s", "[accepted]");
2075 * Create a new session and process group since the 4.4BSD
2076 * setlogin() affects the entire process group. We don't
2077 * want the child to be able to affect the parent.
2079 #if !defined(SSHD_ACQUIRES_CTTY)
2081 * If setsid is called, on some platforms sshd will later acquire a
2082 * controlling terminal which will result in "could not set
2083 * controlling tty" errors.
2085 if (!debug_flag && !inetd_flag && setsid() < 0)
2086 error("setsid: %.100s", strerror(errno));
2092 debug("rexec start in %d out %d newsock %d pipe %d sock %d",
2093 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
2094 dup2(newsock, STDIN_FILENO);
2095 dup2(STDIN_FILENO, STDOUT_FILENO);
2096 if (startup_pipe == -1)
2097 close(REEXEC_STARTUP_PIPE_FD);
2098 else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
2099 dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
2100 close(startup_pipe);
2101 startup_pipe = REEXEC_STARTUP_PIPE_FD;
2104 dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
2107 execv(rexec_argv[0], rexec_argv);
2109 /* Reexec has failed, fall back and continue */
2110 error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
2111 recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
2112 log_init(__progname, options.log_level,
2113 options.log_facility, log_stderr);
2116 close(REEXEC_CONFIG_PASS_FD);
2117 newsock = sock_out = sock_in = dup(STDIN_FILENO);
2118 if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
2119 dup2(fd, STDIN_FILENO);
2120 dup2(fd, STDOUT_FILENO);
2121 if (fd > STDERR_FILENO)
2124 debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
2125 sock_in, sock_out, newsock, startup_pipe, config_s[0]);
2128 /* Executed child processes don't need these. */
2129 fcntl(sock_out, F_SETFD, FD_CLOEXEC);
2130 fcntl(sock_in, F_SETFD, FD_CLOEXEC);
2133 * Disable the key regeneration alarm. We will not regenerate the
2134 * key since we are no longer in a position to give it to anyone. We
2135 * will not restart on SIGHUP since it no longer makes sense.
2138 signal(SIGALRM, SIG_DFL);
2139 signal(SIGHUP, SIG_DFL);
2140 signal(SIGTERM, SIG_DFL);
2141 signal(SIGQUIT, SIG_DFL);
2142 signal(SIGCHLD, SIG_DFL);
2143 signal(SIGINT, SIG_DFL);
2147 * Initialize the resolver. This may not happen automatically
2148 * before privsep chroot().
2150 if ((_res.options & RES_INIT) == 0) {
2151 debug("res_init()");
2156 * Force GSS-API to parse its configuration and load any
2157 * mechanism plugins.
2161 OM_uint32 minor_status;
2162 gss_indicate_mechs(&minor_status, &mechs);
2163 gss_release_oid_set(&minor_status, &mechs);
2169 * Register our connection. This turns encryption off because we do
2172 packet_set_connection(sock_in, sock_out);
2173 packet_set_server();
2175 /* Set SO_KEEPALIVE if requested. */
2176 if (options.tcp_keep_alive && packet_connection_is_on_socket() &&
2177 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0)
2178 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
2180 if ((remote_port = get_remote_port()) < 0) {
2181 debug("get_remote_port failed");
2186 * We use get_canonical_hostname with usedns = 0 instead of
2187 * get_remote_ipaddr here so IP options will be checked.
2189 (void) get_canonical_hostname(0);
2191 * The rest of the code depends on the fact that
2192 * get_remote_ipaddr() caches the remote ip, even if
2193 * the socket goes away.
2195 remote_ip = get_remote_ipaddr();
2197 #ifdef SSH_AUDIT_EVENTS
2198 audit_connection_from(remote_ip, remote_port);
2201 allow_severity = options.log_facility|LOG_INFO;
2202 deny_severity = options.log_facility|LOG_WARNING;
2203 /* Check whether logins are denied from this host. */
2204 if (packet_connection_is_on_socket()) {
2205 struct request_info req;
2207 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
2210 if (!hosts_access(&req)) {
2211 debug("Connection refused by tcp wrapper");
2214 fatal("libwrap refuse returns");
2217 #endif /* LIBWRAP */
2219 /* Log the connection. */
2220 laddr = get_local_ipaddr(sock_in);
2221 verbose("Connection from %s port %d on %s port %d",
2222 remote_ip, remote_port, laddr, get_local_port());
2226 * We don't want to listen forever unless the other side
2227 * successfully authenticates itself. So we set up an alarm which is
2228 * cleared after successful authentication. A limit of zero
2229 * indicates no limit. Note that we don't set the alarm in debugging
2230 * mode; it is just annoying to have the server exit just when you
2231 * are about to discover the bug.
2233 signal(SIGALRM, grace_alarm_handler);
2235 alarm(options.login_grace_time);
2237 sshd_exchange_identification(sock_in, sock_out);
2239 /* In inetd mode, generate ephemeral key only for proto 1 connections */
2240 if (!compat20 && inetd_flag && sensitive_data.server_key == NULL)
2241 generate_ephemeral_server_key();
2243 packet_set_nonblocking();
2245 /* allocate authentication context */
2246 authctxt = xcalloc(1, sizeof(*authctxt));
2248 authctxt->loginmsg = &loginmsg;
2250 /* XXX global for cleanup, access from other modules */
2251 the_authctxt = authctxt;
2253 /* prepare buffer to collect messages to display to user after login */
2254 buffer_init(&loginmsg);
2260 if (privsep_preauth(authctxt) == 1)
2262 } else if (compat20 && have_agent) {
2263 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
2264 error("Unable to get agent socket: %s", ssh_err(r));
2269 /* perform the key exchange */
2270 /* authenticate user and start session */
2273 do_authentication2(authctxt);
2277 do_authentication(authctxt);
2279 fatal("ssh1 not supported");
2283 * If we use privilege separation, the unprivileged child transfers
2284 * the current keystate and exits
2287 mm_send_keystate(pmonitor);
2293 * Cancel the alarm we set to limit the time taken for
2297 signal(SIGALRM, SIG_DFL);
2298 authctxt->authenticated = 1;
2299 if (startup_pipe != -1) {
2300 close(startup_pipe);
2304 #ifdef SSH_AUDIT_EVENTS
2305 audit_event(SSH_AUTH_SUCCESS);
2309 if (options.gss_authentication) {
2310 temporarily_use_uid(authctxt->pw);
2311 ssh_gssapi_storecreds();
2316 if (options.use_pam) {
2323 * In privilege separation, we fork another child and prepare
2324 * file descriptor passing.
2327 privsep_postauth(authctxt);
2328 /* the monitor process [priv] will not return */
2330 destroy_sensitive_data();
2333 packet_set_timeout(options.client_alive_interval,
2334 options.client_alive_count_max);
2336 /* Try to send all our hostkeys to the client */
2338 notify_hostkeys(active_state);
2340 /* Start session. */
2341 do_authenticated(authctxt);
2343 /* The connection has been terminated. */
2344 packet_get_bytes(&ibytes, &obytes);
2345 verbose("Transferred: sent %llu, received %llu bytes",
2346 (unsigned long long)obytes, (unsigned long long)ibytes);
2348 verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
2351 if (options.use_pam)
2353 #endif /* USE_PAM */
2355 #ifdef SSH_AUDIT_EVENTS
2356 PRIVSEP(audit_event(SSH_CONNECTION_CLOSE));
2369 * Decrypt session_key_int using our private server key and private host key
2370 * (key with larger modulus first).
2373 ssh1_session_key(BIGNUM *session_key_int)
2377 if (BN_cmp(sensitive_data.server_key->rsa->n,
2378 sensitive_data.ssh1_host_key->rsa->n) > 0) {
2379 /* Server key has bigger modulus. */
2380 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
2381 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
2382 SSH_KEY_BITS_RESERVED) {
2383 fatal("do_connection: %s: "
2384 "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
2385 get_remote_ipaddr(),
2386 BN_num_bits(sensitive_data.server_key->rsa->n),
2387 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
2388 SSH_KEY_BITS_RESERVED);
2390 if (rsa_private_decrypt(session_key_int, session_key_int,
2391 sensitive_data.server_key->rsa) != 0)
2393 if (rsa_private_decrypt(session_key_int, session_key_int,
2394 sensitive_data.ssh1_host_key->rsa) != 0)
2397 /* Host key has bigger modulus (or they are equal). */
2398 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
2399 BN_num_bits(sensitive_data.server_key->rsa->n) +
2400 SSH_KEY_BITS_RESERVED) {
2401 fatal("do_connection: %s: "
2402 "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
2403 get_remote_ipaddr(),
2404 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
2405 BN_num_bits(sensitive_data.server_key->rsa->n),
2406 SSH_KEY_BITS_RESERVED);
2408 if (rsa_private_decrypt(session_key_int, session_key_int,
2409 sensitive_data.ssh1_host_key->rsa) != 0)
2411 if (rsa_private_decrypt(session_key_int, session_key_int,
2412 sensitive_data.server_key->rsa) != 0)
2426 BIGNUM *session_key_int, *fake_key_int, *real_key_int;
2427 u_char session_key[SSH_SESSION_KEY_LENGTH];
2428 u_char fake_key_bytes[4096 / 8];
2429 size_t fake_key_len;
2431 u_int cipher_type, auth_mask, protocol_flags;
2434 * Generate check bytes that the client must send back in the user
2435 * packet in order for it to be accepted; this is used to defy ip
2436 * spoofing attacks. Note that this only works against somebody
2437 * doing IP spoofing from a remote machine; any machine on the local
2438 * network can still see outgoing packets and catch the random
2439 * cookie. This only affects rhosts authentication, and this is one
2440 * of the reasons why it is inherently insecure.
2442 arc4random_buf(cookie, sizeof(cookie));
2445 * Send our public key. We include in the packet 64 bits of random
2446 * data that must be matched in the reply in order to prevent IP
2449 packet_start(SSH_SMSG_PUBLIC_KEY);
2450 for (i = 0; i < 8; i++)
2451 packet_put_char(cookie[i]);
2453 /* Store our public server RSA key. */
2454 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
2455 packet_put_bignum(sensitive_data.server_key->rsa->e);
2456 packet_put_bignum(sensitive_data.server_key->rsa->n);
2458 /* Store our public host RSA key. */
2459 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
2460 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
2461 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
2463 /* Put protocol flags. */
2464 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
2466 /* Declare which ciphers we support. */
2467 packet_put_int(cipher_mask_ssh1(0));
2469 /* Declare supported authentication types. */
2471 if (options.rhosts_rsa_authentication)
2472 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
2473 if (options.rsa_authentication)
2474 auth_mask |= 1 << SSH_AUTH_RSA;
2475 if (options.challenge_response_authentication == 1)
2476 auth_mask |= 1 << SSH_AUTH_TIS;
2477 if (options.password_authentication)
2478 auth_mask |= 1 << SSH_AUTH_PASSWORD;
2479 packet_put_int(auth_mask);
2481 /* Send the packet and wait for it to be sent. */
2483 packet_write_wait();
2485 debug("Sent %d bit server key and %d bit host key.",
2486 BN_num_bits(sensitive_data.server_key->rsa->n),
2487 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
2489 /* Read clients reply (cipher type and session key). */
2490 packet_read_expect(SSH_CMSG_SESSION_KEY);
2492 /* Get cipher type and check whether we accept this. */
2493 cipher_type = packet_get_char();
2495 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
2496 packet_disconnect("Warning: client selects unsupported cipher.");
2498 /* Get check bytes from the packet. These must match those we
2499 sent earlier with the public key packet. */
2500 for (i = 0; i < 8; i++)
2501 if (cookie[i] != packet_get_char())
2502 packet_disconnect("IP Spoofing check bytes do not match.");
2504 debug("Encryption type: %.200s", cipher_name(cipher_type));
2506 /* Get the encrypted integer. */
2507 if ((real_key_int = BN_new()) == NULL)
2508 fatal("do_ssh1_kex: BN_new failed");
2509 packet_get_bignum(real_key_int);
2511 protocol_flags = packet_get_int();
2512 packet_set_protocol_flags(protocol_flags);
2515 /* Setup a fake key in case RSA decryption fails */
2516 if ((fake_key_int = BN_new()) == NULL)
2517 fatal("do_ssh1_kex: BN_new failed");
2518 fake_key_len = BN_num_bytes(real_key_int);
2519 if (fake_key_len > sizeof(fake_key_bytes))
2520 fake_key_len = sizeof(fake_key_bytes);
2521 arc4random_buf(fake_key_bytes, fake_key_len);
2522 if (BN_bin2bn(fake_key_bytes, fake_key_len, fake_key_int) == NULL)
2523 fatal("do_ssh1_kex: BN_bin2bn failed");
2525 /* Decrypt real_key_int using host/server keys */
2526 rsafail = PRIVSEP(ssh1_session_key(real_key_int));
2527 /* If decryption failed, use the fake key. Else, the real key. */
2529 session_key_int = fake_key_int;
2531 session_key_int = real_key_int;
2534 * Extract session key from the decrypted integer. The key is in the
2535 * least significant 256 bits of the integer; the first byte of the
2536 * key is in the highest bits.
2538 (void) BN_mask_bits(session_key_int, sizeof(session_key) * 8);
2539 len = BN_num_bytes(session_key_int);
2540 if (len < 0 || (u_int)len > sizeof(session_key)) {
2541 error("do_ssh1_kex: bad session key len from %s: "
2542 "session_key_int %d > sizeof(session_key) %lu",
2543 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
2546 explicit_bzero(session_key, sizeof(session_key));
2547 BN_bn2bin(session_key_int,
2548 session_key + sizeof(session_key) - len);
2550 derive_ssh1_session_id(
2551 sensitive_data.ssh1_host_key->rsa->n,
2552 sensitive_data.server_key->rsa->n,
2553 cookie, session_id);
2555 * Xor the first 16 bytes of the session key with the
2558 for (i = 0; i < 16; i++)
2559 session_key[i] ^= session_id[i];
2562 /* Destroy the private and public keys. No longer. */
2563 destroy_sensitive_data();
2566 mm_ssh1_session_id(session_id);
2568 /* Destroy the decrypted integer. It is no longer needed. */
2569 BN_clear_free(real_key_int);
2570 BN_clear_free(fake_key_int);
2572 /* Set the session key. From this on all communications will be encrypted. */
2573 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
2575 /* Destroy our copy of the session key. It is no longer needed. */
2576 explicit_bzero(session_key, sizeof(session_key));
2578 debug("Received session key; encryption turned on.");
2580 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
2581 packet_start(SSH_SMSG_SUCCESS);
2583 packet_write_wait();
2588 sshd_hostkey_sign(Key *privkey, Key *pubkey, u_char **signature, size_t *slen,
2589 const u_char *data, size_t dlen, const char *alg, u_int flag)
2592 u_int xxx_slen, xxx_dlen = dlen;
2595 if (PRIVSEP(key_sign(privkey, signature, &xxx_slen, data, xxx_dlen,
2597 fatal("%s: key_sign failed", __func__);
2600 } else if (use_privsep) {
2601 if (mm_key_sign(pubkey, signature, &xxx_slen, data, xxx_dlen,
2603 fatal("%s: pubkey_sign failed", __func__);
2607 if ((r = ssh_agent_sign(auth_sock, pubkey, signature, slen,
2608 data, dlen, alg, datafellows)) != 0)
2609 fatal("%s: ssh_agent_sign failed: %s",
2610 __func__, ssh_err(r));
2615 /* SSH2 key exchange */
2619 char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
2623 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
2624 options.kex_algorithms);
2625 myproposal[PROPOSAL_ENC_ALGS_CTOS] = compat_cipher_proposal(
2627 myproposal[PROPOSAL_ENC_ALGS_STOC] = compat_cipher_proposal(
2629 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
2630 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
2632 if (options.compression == COMP_NONE) {
2633 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2634 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
2635 } else if (options.compression == COMP_DELAYED) {
2636 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
2637 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com";
2640 if (options.rekey_limit || options.rekey_interval)
2641 packet_set_rekey_limits(options.rekey_limit,
2642 (time_t)options.rekey_interval);
2644 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
2645 list_hostkey_types());
2647 /* start key exchange */
2648 if ((r = kex_setup(active_state, myproposal)) != 0)
2649 fatal("kex_setup: %s", ssh_err(r));
2650 kex = active_state->kex;
2652 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
2653 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server;
2654 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
2655 kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
2656 # ifdef OPENSSL_HAS_ECC
2657 kex->kex[KEX_ECDH_SHA2] = kexecdh_server;
2660 kex->kex[KEX_C25519_SHA256] = kexc25519_server;
2662 kex->client_version_string=client_version_string;
2663 kex->server_version_string=server_version_string;
2664 kex->load_host_public_key=&get_hostkey_public_by_type;
2665 kex->load_host_private_key=&get_hostkey_private_by_type;
2666 kex->host_key_index=&get_hostkey_index;
2667 kex->sign = sshd_hostkey_sign;
2669 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state);
2671 session_id2 = kex->session_id;
2672 session_id2_len = kex->session_id_len;
2675 /* send 1st encrypted/maced/compressed message */
2676 packet_start(SSH2_MSG_IGNORE);
2677 packet_put_cstring("markus");
2679 packet_write_wait();
2684 /* server specific fatal cleanup */
2689 do_cleanup(the_authctxt);
2690 if (use_privsep && privsep_is_preauth &&
2691 pmonitor != NULL && pmonitor->m_pid > 1) {
2692 debug("Killing privsep child %d", pmonitor->m_pid);
2693 if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
2695 error("%s: kill(%d): %s", __func__,
2696 pmonitor->m_pid, strerror(errno));
2699 #ifdef SSH_AUDIT_EVENTS
2700 /* done after do_cleanup so it can cancel the PAM auth 'thread' */
2701 if (!use_privsep || mm_is_monitor())
2702 audit_event(SSH_CONNECTION_ABANDON);