2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * This program is the ssh daemon. It listens for connections from clients,
6 * and performs authentication, executes use commands or shell, and forwards
7 * information to/from the application to the user client over an encrypted
8 * connection. This can also handle forwarding of X11, TCP/IP, and
9 * authentication agent connections.
11 * As far as I am concerned, the code I have written for this software
12 * can be used freely for any purpose. Any derived versions of this
13 * software must be clearly marked as such, and if the derived work is
14 * incompatible with the protocol description in the RFC file, it must be
15 * called by a name other than "ssh" or "Secure Shell".
17 * SSH2 implementation:
18 * Privilege Separation:
20 * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
21 * Copyright (c) 2002 Niels Provos. All rights reserved.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
26 * 1. Redistributions of source code must retain the above copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
33 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
34 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
35 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
36 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
38 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
39 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
41 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
45 RCSID("$OpenBSD: sshd.c,v 1.287 2004/02/25 00:22:45 djm Exp $");
47 #include <openssl/dh.h>
48 #include <openssl/bn.h>
49 #include <openssl/md5.h>
50 #include <openssl/rand.h>
51 #ifdef HAVE_SECUREWARE
52 #include <sys/security.h>
73 #include "myproposal.h"
75 #include "pathnames.h"
83 #include "monitor_mm.h"
85 #include "monitor_wrap.h"
86 #include "monitor_fdpass.h"
91 int allow_severity = LOG_INFO;
92 int deny_severity = LOG_WARNING;
99 #ifdef HAVE___PROGNAME
100 extern char *__progname;
104 extern char **environ;
106 /* Server configuration options. */
107 ServerOptions options;
109 /* Name of the server configuration file. */
110 char *config_file_name = _PATH_SERVER_CONFIG_FILE;
113 * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
114 * Default value is AF_UNSPEC means both IPv4 and IPv6.
116 int IPv4or6 = AF_UNSPEC;
119 * Debug mode flag. This can be set on the command line. If debug
120 * mode is enabled, extra debugging output will be sent to the system
121 * log, the daemon will not go to background, and will exit after processing
122 * the first connection.
126 /* Flag indicating that the daemon should only test the configuration and keys. */
129 /* Flag indicating that the daemon is being started from inetd. */
132 /* Flag indicating that sshd should not detach and become a daemon. */
133 int no_daemon_flag = 0;
135 /* debug goes to stderr unless inetd_flag is set */
138 /* Saved arguments to main(). */
143 * The sockets that the server is listening; this is used in the SIGHUP
146 #define MAX_LISTEN_SOCKS 16
147 int listen_socks[MAX_LISTEN_SOCKS];
148 int num_listen_socks = 0;
151 * the client's version string, passed by sshd2 in compat mode. if != NULL,
152 * sshd will skip the version-number exchange
154 char *client_version_string = NULL;
155 char *server_version_string = NULL;
157 /* for rekeying XXX fixme */
161 * Any really sensitive data in the application is contained in this
162 * structure. The idea is that this structure could be locked into memory so
163 * that the pages do not get written into swap. However, there are some
164 * problems. The private key contains BIGNUMs, and we do not (in principle)
165 * have access to the internals of them, and locking just the structure is
166 * not very useful. Currently, memory locking is not implemented.
169 Key *server_key; /* ephemeral server key */
170 Key *ssh1_host_key; /* ssh1 host key */
171 Key **host_keys; /* all private host keys */
174 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
178 * Flag indicating whether the RSA server key needs to be regenerated.
179 * Is set in the SIGALRM handler and cleared when the key is regenerated.
181 static volatile sig_atomic_t key_do_regen = 0;
183 /* This is set to true when a signal is received. */
184 static volatile sig_atomic_t received_sighup = 0;
185 static volatile sig_atomic_t received_sigterm = 0;
187 /* session identifier, used by RSA-auth */
188 u_char session_id[16];
191 u_char *session_id2 = NULL;
192 u_int session_id2_len = 0;
194 /* record remote hostname or ip */
195 u_int utmp_len = MAXHOSTNAMELEN;
197 /* options.max_startup sized array of fd ints */
198 int *startup_pipes = NULL;
199 int startup_pipe; /* in child */
201 /* variables used for privilege separation */
203 struct monitor *pmonitor = NULL;
205 /* message to be displayed after login */
208 /* global authentication context */
209 Authctxt *the_authctxt = NULL;
211 /* Prototypes for various functions defined later in this file. */
212 void destroy_sensitive_data(void);
213 void demote_sensitive_data(void);
215 static void do_ssh1_kex(void);
216 static void do_ssh2_kex(void);
219 * Close all listening sockets
222 close_listen_socks(void)
226 for (i = 0; i < num_listen_socks; i++)
227 close(listen_socks[i]);
228 num_listen_socks = -1;
232 close_startup_pipes(void)
237 for (i = 0; i < options.max_startups; i++)
238 if (startup_pipes[i] != -1)
239 close(startup_pipes[i]);
243 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
244 * the effect is to reread the configuration file (and to regenerate
248 sighup_handler(int sig)
250 int save_errno = errno;
253 signal(SIGHUP, sighup_handler);
258 * Called from the main program after receiving SIGHUP.
259 * Restarts the server.
264 logit("Received SIGHUP; restarting.");
265 close_listen_socks();
266 close_startup_pipes();
267 execv(saved_argv[0], saved_argv);
268 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
274 * Generic signal handler for terminating signals in the master daemon.
277 sigterm_handler(int sig)
279 received_sigterm = sig;
283 * SIGCHLD handler. This is called whenever a child dies. This will then
284 * reap any zombies left by exited children.
287 main_sigchld_handler(int sig)
289 int save_errno = errno;
293 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
294 (pid < 0 && errno == EINTR))
297 signal(SIGCHLD, main_sigchld_handler);
302 * Signal handler for the alarm after the login grace period has expired.
305 grace_alarm_handler(int sig)
307 /* XXX no idea how fix this signal handler */
309 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
310 kill(pmonitor->m_pid, SIGALRM);
312 /* Log error and exit. */
313 fatal("Timeout before authentication for %s", get_remote_ipaddr());
317 * Signal handler for the key regeneration alarm. Note that this
318 * alarm only occurs in the daemon waiting for connections, and it does not
319 * do anything with the private key or random state before forking.
320 * Thus there should be no concurrency control/asynchronous execution
324 generate_ephemeral_server_key(void)
329 verbose("Generating %s%d bit RSA key.",
330 sensitive_data.server_key ? "new " : "", options.server_key_bits);
331 if (sensitive_data.server_key != NULL)
332 key_free(sensitive_data.server_key);
333 sensitive_data.server_key = key_generate(KEY_RSA1,
334 options.server_key_bits);
335 verbose("RSA key generation complete.");
337 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
340 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
347 key_regeneration_alarm(int sig)
349 int save_errno = errno;
351 signal(SIGALRM, SIG_DFL);
357 sshd_exchange_identification(int sock_in, int sock_out)
360 int remote_major, remote_minor;
363 char buf[256]; /* Must not be larger than remote_version. */
364 char remote_version[256]; /* Must be at least as big as buf. */
366 if ((options.protocol & SSH_PROTO_1) &&
367 (options.protocol & SSH_PROTO_2)) {
368 major = PROTOCOL_MAJOR_1;
370 } else if (options.protocol & SSH_PROTO_2) {
371 major = PROTOCOL_MAJOR_2;
372 minor = PROTOCOL_MINOR_2;
374 major = PROTOCOL_MAJOR_1;
375 minor = PROTOCOL_MINOR_1;
377 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
378 server_version_string = xstrdup(buf);
380 /* Send our protocol version identification. */
381 if (atomicio(vwrite, sock_out, server_version_string,
382 strlen(server_version_string))
383 != strlen(server_version_string)) {
384 logit("Could not write ident string to %s", get_remote_ipaddr());
388 /* Read other sides version identification. */
389 memset(buf, 0, sizeof(buf));
390 for (i = 0; i < sizeof(buf) - 1; i++) {
391 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
392 logit("Did not receive identification string from %s",
393 get_remote_ipaddr());
396 if (buf[i] == '\r') {
398 /* Kludge for F-Secure Macintosh < 1.0.2 */
400 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
404 if (buf[i] == '\n') {
409 buf[sizeof(buf) - 1] = 0;
410 client_version_string = xstrdup(buf);
413 * Check that the versions match. In future this might accept
414 * several versions and set appropriate flags to handle them.
416 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
417 &remote_major, &remote_minor, remote_version) != 3) {
418 s = "Protocol mismatch.\n";
419 (void) atomicio(vwrite, sock_out, s, strlen(s));
422 logit("Bad protocol version identification '%.100s' from %s",
423 client_version_string, get_remote_ipaddr());
426 debug("Client protocol version %d.%d; client software version %.100s",
427 remote_major, remote_minor, remote_version);
429 compat_datafellows(remote_version);
431 if (datafellows & SSH_BUG_PROBE) {
432 logit("probed from %s with %s. Don't panic.",
433 get_remote_ipaddr(), client_version_string);
437 if (datafellows & SSH_BUG_SCANNER) {
438 logit("scanned from %s with %s. Don't panic.",
439 get_remote_ipaddr(), client_version_string);
444 switch (remote_major) {
446 if (remote_minor == 99) {
447 if (options.protocol & SSH_PROTO_2)
453 if (!(options.protocol & SSH_PROTO_1)) {
457 if (remote_minor < 3) {
458 packet_disconnect("Your ssh version is too old and "
459 "is no longer supported. Please install a newer version.");
460 } else if (remote_minor == 3) {
461 /* note that this disables agent-forwarding */
466 if (options.protocol & SSH_PROTO_2) {
475 chop(server_version_string);
476 debug("Local version string %.200s", server_version_string);
479 s = "Protocol major versions differ.\n";
480 (void) atomicio(vwrite, sock_out, s, strlen(s));
483 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
485 server_version_string, client_version_string);
490 /* Destroy the host and server keys. They will no longer be needed. */
492 destroy_sensitive_data(void)
496 if (sensitive_data.server_key) {
497 key_free(sensitive_data.server_key);
498 sensitive_data.server_key = NULL;
500 for (i = 0; i < options.num_host_key_files; i++) {
501 if (sensitive_data.host_keys[i]) {
502 key_free(sensitive_data.host_keys[i]);
503 sensitive_data.host_keys[i] = NULL;
506 sensitive_data.ssh1_host_key = NULL;
507 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
510 /* Demote private to public keys for network child */
512 demote_sensitive_data(void)
517 if (sensitive_data.server_key) {
518 tmp = key_demote(sensitive_data.server_key);
519 key_free(sensitive_data.server_key);
520 sensitive_data.server_key = tmp;
523 for (i = 0; i < options.num_host_key_files; i++) {
524 if (sensitive_data.host_keys[i]) {
525 tmp = key_demote(sensitive_data.host_keys[i]);
526 key_free(sensitive_data.host_keys[i]);
527 sensitive_data.host_keys[i] = tmp;
528 if (tmp->type == KEY_RSA1)
529 sensitive_data.ssh1_host_key = tmp;
533 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
537 privsep_preauth_child(void)
544 /* Enable challenge-response authentication for privilege separation */
545 privsep_challenge_enable();
547 for (i = 0; i < 256; i++)
548 rnd[i] = arc4random();
549 RAND_seed(rnd, sizeof(rnd));
551 /* Demote the private keys to public keys. */
552 demote_sensitive_data();
554 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
555 fatal("Privilege separation user %s does not exist",
557 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
560 /* Change our root directory */
561 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
562 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
564 if (chdir("/") == -1)
565 fatal("chdir(\"/\"): %s", strerror(errno));
567 /* Drop our privileges */
568 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
571 /* XXX not ready, too heavy after chroot */
572 do_setusercontext(pw);
574 gidset[0] = pw->pw_gid;
575 if (setgroups(1, gidset) < 0)
576 fatal("setgroups: %.100s", strerror(errno));
577 permanently_set_uid(pw);
582 privsep_preauth(Authctxt *authctxt)
587 /* Set up unprivileged child process to deal with network data */
588 pmonitor = monitor_init();
589 /* Store a pointer to the kex for later rekeying */
590 pmonitor->m_pkex = &xxx_kex;
594 fatal("fork of unprivileged child failed");
595 } else if (pid != 0) {
596 debug2("Network child is on pid %ld", (long)pid);
598 close(pmonitor->m_recvfd);
599 pmonitor->m_pid = pid;
600 monitor_child_preauth(authctxt, pmonitor);
601 close(pmonitor->m_sendfd);
604 monitor_sync(pmonitor);
606 /* Wait for the child's exit status */
607 while (waitpid(pid, &status, 0) < 0)
614 close(pmonitor->m_sendfd);
616 /* Demote the child */
617 if (getuid() == 0 || geteuid() == 0)
618 privsep_preauth_child();
619 setproctitle("%s", "[net]");
625 privsep_postauth(Authctxt *authctxt)
627 #ifdef DISABLE_FD_PASSING
630 if (authctxt->pw->pw_uid == 0 || options.use_login) {
632 /* File descriptor passing is broken or root login */
633 monitor_apply_keystate(pmonitor);
638 /* Authentication complete */
640 if (startup_pipe != -1) {
645 /* New socket pair */
646 monitor_reinit(pmonitor);
648 pmonitor->m_pid = fork();
649 if (pmonitor->m_pid == -1)
650 fatal("fork of unprivileged child failed");
651 else if (pmonitor->m_pid != 0) {
652 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
653 close(pmonitor->m_recvfd);
654 monitor_child_postauth(pmonitor);
660 close(pmonitor->m_sendfd);
662 /* Demote the private keys to public keys. */
663 demote_sensitive_data();
665 /* Drop privileges */
666 do_setusercontext(authctxt->pw);
668 /* It is safe now to apply the key state */
669 monitor_apply_keystate(pmonitor);
673 list_hostkey_types(void)
681 for (i = 0; i < options.num_host_key_files; i++) {
682 Key *key = sensitive_data.host_keys[i];
688 if (buffer_len(&b) > 0)
689 buffer_append(&b, ",", 1);
690 p = key_ssh_name(key);
691 buffer_append(&b, p, strlen(p));
695 buffer_append(&b, "\0", 1);
696 ret = xstrdup(buffer_ptr(&b));
698 debug("list_hostkey_types: %s", ret);
703 get_hostkey_by_type(int type)
707 for (i = 0; i < options.num_host_key_files; i++) {
708 Key *key = sensitive_data.host_keys[i];
709 if (key != NULL && key->type == type)
716 get_hostkey_by_index(int ind)
718 if (ind < 0 || ind >= options.num_host_key_files)
720 return (sensitive_data.host_keys[ind]);
724 get_hostkey_index(Key *key)
728 for (i = 0; i < options.num_host_key_files; i++) {
729 if (key == sensitive_data.host_keys[i])
736 * returns 1 if connection should be dropped, 0 otherwise.
737 * dropping starts at connection #max_startups_begin with a probability
738 * of (max_startups_rate/100). the probability increases linearly until
739 * all connections are dropped for startups > max_startups
742 drop_connection(int startups)
746 if (startups < options.max_startups_begin)
748 if (startups >= options.max_startups)
750 if (options.max_startups_rate == 100)
753 p = 100 - options.max_startups_rate;
754 p *= startups - options.max_startups_begin;
755 p /= (double) (options.max_startups - options.max_startups_begin);
756 p += options.max_startups_rate;
758 r = arc4random() / (double) UINT_MAX;
760 debug("drop_connection: p %g, r %g", p, r);
761 return (r < p) ? 1 : 0;
767 fprintf(stderr, "sshd version %s, %s\n",
768 SSH_VERSION, SSLeay_version(SSLEAY_VERSION));
769 fprintf(stderr, "Usage: %s [options]\n", __progname);
770 fprintf(stderr, "Options:\n");
771 fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
772 fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
773 fprintf(stderr, " -i Started from inetd\n");
774 fprintf(stderr, " -D Do not fork into daemon mode\n");
775 fprintf(stderr, " -t Only test configuration file and keys\n");
776 fprintf(stderr, " -q Quiet (no logging)\n");
777 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
778 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
779 fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
780 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
781 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
782 _PATH_HOST_KEY_FILE);
783 fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
784 fprintf(stderr, " -4 Use IPv4 only\n");
785 fprintf(stderr, " -6 Use IPv6 only\n");
786 fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n");
791 * Main program for the daemon.
794 main(int ac, char **av)
798 int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
802 struct sockaddr_storage from;
803 const char *remote_ip;
807 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
809 int listen_sock, maxfd;
814 int ret, key_used = 0;
816 #ifdef HAVE_SECUREWARE
817 (void)set_auth_parameters(ac, av);
819 __progname = ssh_get_progname(av[0]);
822 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
824 saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1));
825 for (i = 0; i < ac; i++)
826 saved_argv[i] = xstrdup(av[i]);
827 saved_argv[i] = NULL;
829 #ifndef HAVE_SETPROCTITLE
830 /* Prepare for later setproctitle emulation */
831 compat_init_setproctitle(ac, av);
835 /* Initialize configuration options to their default values. */
836 initialize_server_options(&options);
838 /* Parse command-line arguments. */
839 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqtQ46")) != -1) {
848 config_file_name = optarg;
851 if (debug_flag == 0) {
853 options.log_level = SYSLOG_LEVEL_DEBUG1;
854 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
870 options.log_level = SYSLOG_LEVEL_QUIET;
873 options.server_key_bits = atoi(optarg);
876 options.ports_from_cmdline = 1;
877 if (options.num_ports >= MAX_PORTS) {
878 fprintf(stderr, "too many ports.\n");
881 options.ports[options.num_ports++] = a2port(optarg);
882 if (options.ports[options.num_ports-1] == 0) {
883 fprintf(stderr, "Bad port number.\n");
888 if ((options.login_grace_time = convtime(optarg)) == -1) {
889 fprintf(stderr, "Invalid login grace time.\n");
894 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
895 fprintf(stderr, "Invalid key regeneration interval.\n");
900 if (options.num_host_key_files >= MAX_HOSTKEYS) {
901 fprintf(stderr, "too many host keys.\n");
904 options.host_key_files[options.num_host_key_files++] = optarg;
910 utmp_len = atoi(optarg);
911 if (utmp_len > MAXHOSTNAMELEN) {
912 fprintf(stderr, "Invalid utmp length.\n");
917 line = xstrdup(optarg);
918 if (process_server_config_line(&options, line,
919 "command-line", 0) != 0)
929 SSLeay_add_all_algorithms();
930 channel_set_af(IPv4or6);
933 * Force logging to stderr until we have loaded the private host
934 * key (unless started from inetd)
937 options.log_level == SYSLOG_LEVEL_NOT_SET ?
938 SYSLOG_LEVEL_INFO : options.log_level,
939 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
940 SYSLOG_FACILITY_AUTH : options.log_facility,
941 log_stderr || !inetd_flag);
944 /* Cray can define user privs drop all prives now!
945 * Not needed on PRIV_SU systems!
952 /* Read server configuration options from the configuration file. */
953 read_server_config(&options, config_file_name);
955 /* Fill in default values for those options not explicitly set. */
956 fill_default_server_options(&options);
958 /* Check that there are no remaining arguments. */
960 fprintf(stderr, "Extra argument %s.\n", av[optind]);
964 debug("sshd version %.100s", SSH_VERSION);
966 /* load private host keys */
967 sensitive_data.host_keys = xmalloc(options.num_host_key_files *
969 for (i = 0; i < options.num_host_key_files; i++)
970 sensitive_data.host_keys[i] = NULL;
971 sensitive_data.server_key = NULL;
972 sensitive_data.ssh1_host_key = NULL;
973 sensitive_data.have_ssh1_key = 0;
974 sensitive_data.have_ssh2_key = 0;
976 for (i = 0; i < options.num_host_key_files; i++) {
977 key = key_load_private(options.host_key_files[i], "", NULL);
978 sensitive_data.host_keys[i] = key;
980 error("Could not load host key: %s",
981 options.host_key_files[i]);
982 sensitive_data.host_keys[i] = NULL;
987 sensitive_data.ssh1_host_key = key;
988 sensitive_data.have_ssh1_key = 1;
992 sensitive_data.have_ssh2_key = 1;
995 debug("private host key: #%d type %d %s", i, key->type,
998 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
999 logit("Disabling protocol version 1. Could not load host key");
1000 options.protocol &= ~SSH_PROTO_1;
1002 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1003 logit("Disabling protocol version 2. Could not load host key");
1004 options.protocol &= ~SSH_PROTO_2;
1006 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1007 logit("sshd: no hostkeys available -- exiting.");
1011 /* Check certain values for sanity. */
1012 if (options.protocol & SSH_PROTO_1) {
1013 if (options.server_key_bits < 512 ||
1014 options.server_key_bits > 32768) {
1015 fprintf(stderr, "Bad server key size.\n");
1019 * Check that server and host key lengths differ sufficiently. This
1020 * is necessary to make double encryption work with rsaref. Oh, I
1021 * hate software patents. I dont know if this can go? Niels
1023 if (options.server_key_bits >
1024 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1025 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1026 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1027 SSH_KEY_BITS_RESERVED) {
1028 options.server_key_bits =
1029 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1030 SSH_KEY_BITS_RESERVED;
1031 debug("Forcing server key to %d bits to make it differ from host key.",
1032 options.server_key_bits);
1040 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1041 fatal("Privilege separation user %s does not exist",
1043 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1044 (S_ISDIR(st.st_mode) == 0))
1045 fatal("Missing privilege separation directory: %s",
1046 _PATH_PRIVSEP_CHROOT_DIR);
1049 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1050 (st.st_uid != getuid () ||
1051 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1053 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1055 fatal("%s must be owned by root and not group or "
1056 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1059 /* Configuration looks good, so exit if in test mode. */
1064 * Clear out any supplemental groups we may have inherited. This
1065 * prevents inadvertent creation of files with bad modes (in the
1066 * portable version at least, it's certainly possible for PAM
1067 * to create a file, and we can't control the code in every
1068 * module which might be used).
1070 if (setgroups(0, NULL) < 0)
1071 debug("setgroups() failed: %.200s", strerror(errno));
1073 /* Initialize the log (it is reinitialized below in case we forked). */
1074 if (debug_flag && !inetd_flag)
1076 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1079 * If not in debugging mode, and not started from inetd, disconnect
1080 * from the controlling terminal, and fork. The original process
1083 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1086 #endif /* TIOCNOTTY */
1087 if (daemon(0, 0) < 0)
1088 fatal("daemon() failed: %.200s", strerror(errno));
1090 /* Disconnect from the controlling tty. */
1092 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
1094 (void) ioctl(fd, TIOCNOTTY, NULL);
1097 #endif /* TIOCNOTTY */
1099 /* Reinitialize the log (because of the fork above). */
1100 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1102 /* Initialize the random number generator. */
1105 /* Chdir to the root directory so that the current disk can be
1106 unmounted if desired. */
1110 /* Clear environment */
1114 /* ignore SIGPIPE */
1115 signal(SIGPIPE, SIG_IGN);
1117 /* Start listening for a socket, unless started from inetd. */
1120 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
1126 * We intentionally do not close the descriptors 0, 1, and 2
1127 * as our code for setting the descriptors won\'t work if
1128 * ttyfd happens to be one of those.
1130 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
1131 if (options.protocol & SSH_PROTO_1)
1132 generate_ephemeral_server_key();
1134 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1135 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1137 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1138 fatal("Too many listen sockets. "
1139 "Enlarge MAX_LISTEN_SOCKS");
1140 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
1141 ntop, sizeof(ntop), strport, sizeof(strport),
1142 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1143 error("getnameinfo failed");
1146 /* Create socket for listening. */
1147 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1149 if (listen_sock < 0) {
1150 /* kernel may not support ipv6 */
1151 verbose("socket: %.100s", strerror(errno));
1154 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
1155 error("listen_sock O_NONBLOCK: %s", strerror(errno));
1160 * Set socket options.
1161 * Allow local port reuse in TIME_WAIT.
1163 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1164 &on, sizeof(on)) == -1)
1165 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1167 debug("Bind to port %s on %s.", strport, ntop);
1169 /* Bind the socket to the desired port. */
1170 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1172 error("Bind to port %s on %s failed: %.200s.",
1173 strport, ntop, strerror(errno));
1177 listen_socks[num_listen_socks] = listen_sock;
1180 /* Start listening on the port. */
1181 logit("Server listening on %s port %s.", ntop, strport);
1182 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1183 fatal("listen: %.100s", strerror(errno));
1186 freeaddrinfo(options.listen_addrs);
1188 if (!num_listen_socks)
1189 fatal("Cannot bind any address.");
1191 if (options.protocol & SSH_PROTO_1)
1192 generate_ephemeral_server_key();
1195 * Arrange to restart on SIGHUP. The handler needs
1198 signal(SIGHUP, sighup_handler);
1200 signal(SIGTERM, sigterm_handler);
1201 signal(SIGQUIT, sigterm_handler);
1203 /* Arrange SIGCHLD to be caught. */
1204 signal(SIGCHLD, main_sigchld_handler);
1206 /* Write out the pid file after the sigterm handler is setup */
1209 * Record our pid in /var/run/sshd.pid to make it
1210 * easier to kill the correct sshd. We don't want to
1211 * do this before the bind above because the bind will
1212 * fail if there already is a daemon, and this will
1213 * overwrite any old pid in the file.
1215 f = fopen(options.pid_file, "wb");
1217 error("Couldn't create pid file \"%s\": %s",
1218 options.pid_file, strerror(errno));
1220 fprintf(f, "%ld\n", (long) getpid());
1225 /* setup fd set for listen */
1228 for (i = 0; i < num_listen_socks; i++)
1229 if (listen_socks[i] > maxfd)
1230 maxfd = listen_socks[i];
1231 /* pipes connected to unauthenticated childs */
1232 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1233 for (i = 0; i < options.max_startups; i++)
1234 startup_pipes[i] = -1;
1237 * Stay listening for connections until the system crashes or
1238 * the daemon is killed with a signal.
1241 if (received_sighup)
1245 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
1246 fdset = (fd_set *)xmalloc(fdsetsz);
1247 memset(fdset, 0, fdsetsz);
1249 for (i = 0; i < num_listen_socks; i++)
1250 FD_SET(listen_socks[i], fdset);
1251 for (i = 0; i < options.max_startups; i++)
1252 if (startup_pipes[i] != -1)
1253 FD_SET(startup_pipes[i], fdset);
1255 /* Wait in select until there is a connection. */
1256 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1257 if (ret < 0 && errno != EINTR)
1258 error("select: %.100s", strerror(errno));
1259 if (received_sigterm) {
1260 logit("Received signal %d; terminating.",
1261 (int) received_sigterm);
1262 close_listen_socks();
1263 unlink(options.pid_file);
1266 if (key_used && key_do_regen) {
1267 generate_ephemeral_server_key();
1274 for (i = 0; i < options.max_startups; i++)
1275 if (startup_pipes[i] != -1 &&
1276 FD_ISSET(startup_pipes[i], fdset)) {
1278 * the read end of the pipe is ready
1279 * if the child has closed the pipe
1280 * after successful authentication
1281 * or if the child has died
1283 close(startup_pipes[i]);
1284 startup_pipes[i] = -1;
1287 for (i = 0; i < num_listen_socks; i++) {
1288 if (!FD_ISSET(listen_socks[i], fdset))
1290 fromlen = sizeof(from);
1291 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1294 if (errno != EINTR && errno != EWOULDBLOCK)
1295 error("accept: %.100s", strerror(errno));
1298 if (fcntl(newsock, F_SETFL, 0) < 0) {
1299 error("newsock del O_NONBLOCK: %s", strerror(errno));
1303 if (drop_connection(startups) == 1) {
1304 debug("drop connection #%d", startups);
1308 if (pipe(startup_p) == -1) {
1313 for (j = 0; j < options.max_startups; j++)
1314 if (startup_pipes[j] == -1) {
1315 startup_pipes[j] = startup_p[0];
1316 if (maxfd < startup_p[0])
1317 maxfd = startup_p[0];
1323 * Got connection. Fork a child to handle it, unless
1324 * we are in debugging mode.
1328 * In debugging mode. Close the listening
1329 * socket, and start processing the
1330 * connection without forking.
1332 debug("Server will not fork when running in debugging mode.");
1333 close_listen_socks();
1341 * Normal production daemon. Fork, and have
1342 * the child process the connection. The
1343 * parent continues listening.
1345 if ((pid = fork()) == 0) {
1347 * Child. Close the listening and max_startup
1348 * sockets. Start using the accepted socket.
1349 * Reinitialize logging (since our pid has
1350 * changed). We break out of the loop to handle
1353 startup_pipe = startup_p[1];
1354 close_startup_pipes();
1355 close_listen_socks();
1358 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1363 /* Parent. Stay in the loop. */
1365 error("fork: %.100s", strerror(errno));
1367 debug("Forked child %ld.", (long)pid);
1369 close(startup_p[1]);
1371 /* Mark that the key has been used (it was "given" to the child). */
1372 if ((options.protocol & SSH_PROTO_1) &&
1374 /* Schedule server key regeneration alarm. */
1375 signal(SIGALRM, key_regeneration_alarm);
1376 alarm(options.key_regeneration_time);
1382 /* Close the new socket (the child is now taking care of it). */
1385 /* child process check (or debug mode) */
1386 if (num_listen_socks < 0)
1391 /* This is the child processing a new connection. */
1394 * Create a new session and process group since the 4.4BSD
1395 * setlogin() affects the entire process group. We don't
1396 * want the child to be able to affect the parent.
1398 #if !defined(SSHD_ACQUIRES_CTTY)
1400 * If setsid is called, on some platforms sshd will later acquire a
1401 * controlling terminal which will result in "could not set
1402 * controlling tty" errors.
1404 if (!debug_flag && !inetd_flag && setsid() < 0)
1405 error("setsid: %.100s", strerror(errno));
1409 * Disable the key regeneration alarm. We will not regenerate the
1410 * key since we are no longer in a position to give it to anyone. We
1411 * will not restart on SIGHUP since it no longer makes sense.
1414 signal(SIGALRM, SIG_DFL);
1415 signal(SIGHUP, SIG_DFL);
1416 signal(SIGTERM, SIG_DFL);
1417 signal(SIGQUIT, SIG_DFL);
1418 signal(SIGCHLD, SIG_DFL);
1419 signal(SIGINT, SIG_DFL);
1421 /* Set SO_KEEPALIVE if requested. */
1422 if (options.tcp_keep_alive &&
1423 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
1425 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1428 * Register our connection. This turns encryption off because we do
1431 packet_set_connection(sock_in, sock_out);
1433 remote_port = get_remote_port();
1434 remote_ip = get_remote_ipaddr();
1437 /* Check whether logins are denied from this host. */
1439 struct request_info req;
1441 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
1444 if (!hosts_access(&req)) {
1445 debug("Connection refused by tcp wrapper");
1448 fatal("libwrap refuse returns");
1451 #endif /* LIBWRAP */
1453 /* Log the connection. */
1454 verbose("Connection from %.500s port %d", remote_ip, remote_port);
1457 * We don\'t want to listen forever unless the other side
1458 * successfully authenticates itself. So we set up an alarm which is
1459 * cleared after successful authentication. A limit of zero
1460 * indicates no limit. Note that we don\'t set the alarm in debugging
1461 * mode; it is just annoying to have the server exit just when you
1462 * are about to discover the bug.
1464 signal(SIGALRM, grace_alarm_handler);
1466 alarm(options.login_grace_time);
1468 sshd_exchange_identification(sock_in, sock_out);
1470 packet_set_nonblocking();
1472 /* prepare buffers to collect authentication messages */
1473 buffer_init(&loginmsg);
1475 /* allocate authentication context */
1476 authctxt = xmalloc(sizeof(*authctxt));
1477 memset(authctxt, 0, sizeof(*authctxt));
1479 /* XXX global for cleanup, access from other modules */
1480 the_authctxt = authctxt;
1483 if (privsep_preauth(authctxt) == 1)
1486 /* perform the key exchange */
1487 /* authenticate user and start session */
1490 do_authentication2(authctxt);
1493 do_authentication(authctxt);
1496 * If we use privilege separation, the unprivileged child transfers
1497 * the current keystate and exits
1500 mm_send_keystate(pmonitor);
1506 * In privilege separation, we fork another child and prepare
1507 * file descriptor passing.
1510 privsep_postauth(authctxt);
1511 /* the monitor process [priv] will not return */
1513 destroy_sensitive_data();
1516 /* Start session. */
1517 do_authenticated(authctxt);
1519 /* The connection has been terminated. */
1520 verbose("Closing connection to %.100s", remote_ip);
1523 if (options.use_pam)
1525 #endif /* USE_PAM */
1536 * Decrypt session_key_int using our private server key and private host key
1537 * (key with larger modulus first).
1540 ssh1_session_key(BIGNUM *session_key_int)
1544 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1545 /* Server key has bigger modulus. */
1546 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1547 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1548 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1549 get_remote_ipaddr(),
1550 BN_num_bits(sensitive_data.server_key->rsa->n),
1551 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1552 SSH_KEY_BITS_RESERVED);
1554 if (rsa_private_decrypt(session_key_int, session_key_int,
1555 sensitive_data.server_key->rsa) <= 0)
1557 if (rsa_private_decrypt(session_key_int, session_key_int,
1558 sensitive_data.ssh1_host_key->rsa) <= 0)
1561 /* Host key has bigger modulus (or they are equal). */
1562 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1563 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1564 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1565 get_remote_ipaddr(),
1566 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1567 BN_num_bits(sensitive_data.server_key->rsa->n),
1568 SSH_KEY_BITS_RESERVED);
1570 if (rsa_private_decrypt(session_key_int, session_key_int,
1571 sensitive_data.ssh1_host_key->rsa) < 0)
1573 if (rsa_private_decrypt(session_key_int, session_key_int,
1574 sensitive_data.server_key->rsa) < 0)
1587 BIGNUM *session_key_int;
1588 u_char session_key[SSH_SESSION_KEY_LENGTH];
1590 u_int cipher_type, auth_mask, protocol_flags;
1594 * Generate check bytes that the client must send back in the user
1595 * packet in order for it to be accepted; this is used to defy ip
1596 * spoofing attacks. Note that this only works against somebody
1597 * doing IP spoofing from a remote machine; any machine on the local
1598 * network can still see outgoing packets and catch the random
1599 * cookie. This only affects rhosts authentication, and this is one
1600 * of the reasons why it is inherently insecure.
1602 for (i = 0; i < 8; i++) {
1605 cookie[i] = rnd & 0xff;
1610 * Send our public key. We include in the packet 64 bits of random
1611 * data that must be matched in the reply in order to prevent IP
1614 packet_start(SSH_SMSG_PUBLIC_KEY);
1615 for (i = 0; i < 8; i++)
1616 packet_put_char(cookie[i]);
1618 /* Store our public server RSA key. */
1619 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1620 packet_put_bignum(sensitive_data.server_key->rsa->e);
1621 packet_put_bignum(sensitive_data.server_key->rsa->n);
1623 /* Store our public host RSA key. */
1624 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1625 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1626 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
1628 /* Put protocol flags. */
1629 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1631 /* Declare which ciphers we support. */
1632 packet_put_int(cipher_mask_ssh1(0));
1634 /* Declare supported authentication types. */
1636 if (options.rhosts_rsa_authentication)
1637 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1638 if (options.rsa_authentication)
1639 auth_mask |= 1 << SSH_AUTH_RSA;
1640 if (options.challenge_response_authentication == 1)
1641 auth_mask |= 1 << SSH_AUTH_TIS;
1642 if (options.password_authentication)
1643 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1644 packet_put_int(auth_mask);
1646 /* Send the packet and wait for it to be sent. */
1648 packet_write_wait();
1650 debug("Sent %d bit server key and %d bit host key.",
1651 BN_num_bits(sensitive_data.server_key->rsa->n),
1652 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1654 /* Read clients reply (cipher type and session key). */
1655 packet_read_expect(SSH_CMSG_SESSION_KEY);
1657 /* Get cipher type and check whether we accept this. */
1658 cipher_type = packet_get_char();
1660 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1661 packet_disconnect("Warning: client selects unsupported cipher.");
1663 /* Get check bytes from the packet. These must match those we
1664 sent earlier with the public key packet. */
1665 for (i = 0; i < 8; i++)
1666 if (cookie[i] != packet_get_char())
1667 packet_disconnect("IP Spoofing check bytes do not match.");
1669 debug("Encryption type: %.200s", cipher_name(cipher_type));
1671 /* Get the encrypted integer. */
1672 if ((session_key_int = BN_new()) == NULL)
1673 fatal("do_ssh1_kex: BN_new failed");
1674 packet_get_bignum(session_key_int);
1676 protocol_flags = packet_get_int();
1677 packet_set_protocol_flags(protocol_flags);
1680 /* Decrypt session_key_int using host/server keys */
1681 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1684 * Extract session key from the decrypted integer. The key is in the
1685 * least significant 256 bits of the integer; the first byte of the
1686 * key is in the highest bits.
1689 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1690 len = BN_num_bytes(session_key_int);
1691 if (len < 0 || len > sizeof(session_key)) {
1692 error("do_connection: bad session key len from %s: "
1693 "session_key_int %d > sizeof(session_key) %lu",
1694 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
1697 memset(session_key, 0, sizeof(session_key));
1698 BN_bn2bin(session_key_int,
1699 session_key + sizeof(session_key) - len);
1701 compute_session_id(session_id, cookie,
1702 sensitive_data.ssh1_host_key->rsa->n,
1703 sensitive_data.server_key->rsa->n);
1705 * Xor the first 16 bytes of the session key with the
1708 for (i = 0; i < 16; i++)
1709 session_key[i] ^= session_id[i];
1713 int bytes = BN_num_bytes(session_key_int);
1714 u_char *buf = xmalloc(bytes);
1717 logit("do_connection: generating a fake encryption key");
1718 BN_bn2bin(session_key_int, buf);
1720 MD5_Update(&md, buf, bytes);
1721 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1722 MD5_Final(session_key, &md);
1724 MD5_Update(&md, session_key, 16);
1725 MD5_Update(&md, buf, bytes);
1726 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1727 MD5_Final(session_key + 16, &md);
1728 memset(buf, 0, bytes);
1730 for (i = 0; i < 16; i++)
1731 session_id[i] = session_key[i] ^ session_key[i + 16];
1733 /* Destroy the private and public keys. No longer. */
1734 destroy_sensitive_data();
1737 mm_ssh1_session_id(session_id);
1739 /* Destroy the decrypted integer. It is no longer needed. */
1740 BN_clear_free(session_key_int);
1742 /* Set the session key. From this on all communications will be encrypted. */
1743 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1745 /* Destroy our copy of the session key. It is no longer needed. */
1746 memset(session_key, 0, sizeof(session_key));
1748 debug("Received session key; encryption turned on.");
1750 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
1751 packet_start(SSH_SMSG_SUCCESS);
1753 packet_write_wait();
1757 * SSH2 key exchange: diffie-hellman-group1-sha1
1764 if (options.ciphers != NULL) {
1765 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1766 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1768 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1769 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
1770 myproposal[PROPOSAL_ENC_ALGS_STOC] =
1771 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1773 if (options.macs != NULL) {
1774 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1775 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1777 if (!options.compression) {
1778 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1779 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1781 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1783 /* start key exchange */
1784 kex = kex_setup(myproposal);
1785 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1786 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1788 kex->client_version_string=client_version_string;
1789 kex->server_version_string=server_version_string;
1790 kex->load_host_key=&get_hostkey_by_type;
1791 kex->host_key_index=&get_hostkey_index;
1795 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1797 session_id2 = kex->session_id;
1798 session_id2_len = kex->session_id_len;
1801 /* send 1st encrypted/maced/compressed message */
1802 packet_start(SSH2_MSG_IGNORE);
1803 packet_put_cstring("markus");
1805 packet_write_wait();
1810 /* server specific fatal cleanup */
1815 do_cleanup(the_authctxt);