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 1.286 2004/02/23 12:02:33 markus 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"
93 #include <openssl/md5.h>
100 int allow_severity = LOG_INFO;
101 int deny_severity = LOG_WARNING;
108 #ifdef HAVE___PROGNAME
109 extern char *__progname;
113 extern char **environ;
115 /* Server configuration options. */
116 ServerOptions options;
118 /* Name of the server configuration file. */
119 char *config_file_name = _PATH_SERVER_CONFIG_FILE;
122 * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
123 * Default value is AF_UNSPEC means both IPv4 and IPv6.
125 int IPv4or6 = AF_UNSPEC;
128 * Debug mode flag. This can be set on the command line. If debug
129 * mode is enabled, extra debugging output will be sent to the system
130 * log, the daemon will not go to background, and will exit after processing
131 * the first connection.
135 /* Flag indicating that the daemon should only test the configuration and keys. */
138 /* Flag indicating that the daemon is being started from inetd. */
141 /* Flag indicating that sshd should not detach and become a daemon. */
142 int no_daemon_flag = 0;
144 /* debug goes to stderr unless inetd_flag is set */
147 /* Saved arguments to main(). */
152 * The sockets that the server is listening; this is used in the SIGHUP
155 #define MAX_LISTEN_SOCKS 16
156 int listen_socks[MAX_LISTEN_SOCKS];
157 int num_listen_socks = 0;
160 * the client's version string, passed by sshd2 in compat mode. if != NULL,
161 * sshd will skip the version-number exchange
163 char *client_version_string = NULL;
164 char *server_version_string = NULL;
166 /* for rekeying XXX fixme */
170 * Any really sensitive data in the application is contained in this
171 * structure. The idea is that this structure could be locked into memory so
172 * that the pages do not get written into swap. However, there are some
173 * problems. The private key contains BIGNUMs, and we do not (in principle)
174 * have access to the internals of them, and locking just the structure is
175 * not very useful. Currently, memory locking is not implemented.
178 Key *server_key; /* ephemeral server key */
179 Key *ssh1_host_key; /* ssh1 host key */
180 Key **host_keys; /* all private host keys */
183 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
187 * Flag indicating whether the RSA server key needs to be regenerated.
188 * Is set in the SIGALRM handler and cleared when the key is regenerated.
190 static volatile sig_atomic_t key_do_regen = 0;
192 /* This is set to true when a signal is received. */
193 static volatile sig_atomic_t received_sighup = 0;
194 static volatile sig_atomic_t received_sigterm = 0;
196 /* session identifier, used by RSA-auth */
197 u_char session_id[16];
200 u_char *session_id2 = NULL;
201 u_int session_id2_len = 0;
203 /* record remote hostname or ip */
204 u_int utmp_len = MAXHOSTNAMELEN;
206 /* options.max_startup sized array of fd ints */
207 int *startup_pipes = NULL;
208 int startup_pipe; /* in child */
210 /* variables used for privilege separation */
212 struct monitor *pmonitor = NULL;
214 /* message to be displayed after login */
217 /* global authentication context */
218 Authctxt *the_authctxt = NULL;
220 /* Prototypes for various functions defined later in this file. */
221 void destroy_sensitive_data(void);
222 void demote_sensitive_data(void);
224 static void do_ssh1_kex(void);
225 static void do_ssh2_kex(void);
228 * Close all listening sockets
231 close_listen_socks(void)
235 for (i = 0; i < num_listen_socks; i++)
236 close(listen_socks[i]);
237 num_listen_socks = -1;
241 close_startup_pipes(void)
246 for (i = 0; i < options.max_startups; i++)
247 if (startup_pipes[i] != -1)
248 close(startup_pipes[i]);
252 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
253 * the effect is to reread the configuration file (and to regenerate
257 sighup_handler(int sig)
259 int save_errno = errno;
262 signal(SIGHUP, sighup_handler);
267 * Called from the main program after receiving SIGHUP.
268 * Restarts the server.
273 logit("Received SIGHUP; restarting.");
274 close_listen_socks();
275 close_startup_pipes();
276 execv(saved_argv[0], saved_argv);
277 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
283 * Generic signal handler for terminating signals in the master daemon.
286 sigterm_handler(int sig)
288 received_sigterm = sig;
292 * SIGCHLD handler. This is called whenever a child dies. This will then
293 * reap any zombies left by exited children.
296 main_sigchld_handler(int sig)
298 int save_errno = errno;
302 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
303 (pid < 0 && errno == EINTR))
306 signal(SIGCHLD, main_sigchld_handler);
311 * Signal handler for the alarm after the login grace period has expired.
314 grace_alarm_handler(int sig)
316 /* XXX no idea how fix this signal handler */
318 if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0)
319 kill(pmonitor->m_pid, SIGALRM);
321 /* Log error and exit. */
322 fatal("Timeout before authentication for %s", get_remote_ipaddr());
326 * Signal handler for the key regeneration alarm. Note that this
327 * alarm only occurs in the daemon waiting for connections, and it does not
328 * do anything with the private key or random state before forking.
329 * Thus there should be no concurrency control/asynchronous execution
333 generate_ephemeral_server_key(void)
338 verbose("Generating %s%d bit RSA key.",
339 sensitive_data.server_key ? "new " : "", options.server_key_bits);
340 if (sensitive_data.server_key != NULL)
341 key_free(sensitive_data.server_key);
342 sensitive_data.server_key = key_generate(KEY_RSA1,
343 options.server_key_bits);
344 verbose("RSA key generation complete.");
346 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
349 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
356 key_regeneration_alarm(int sig)
358 int save_errno = errno;
360 signal(SIGALRM, SIG_DFL);
366 sshd_exchange_identification(int sock_in, int sock_out)
369 int remote_major, remote_minor;
372 char buf[256]; /* Must not be larger than remote_version. */
373 char remote_version[256]; /* Must be at least as big as buf. */
375 if ((options.protocol & SSH_PROTO_1) &&
376 (options.protocol & SSH_PROTO_2)) {
377 major = PROTOCOL_MAJOR_1;
379 } else if (options.protocol & SSH_PROTO_2) {
380 major = PROTOCOL_MAJOR_2;
381 minor = PROTOCOL_MINOR_2;
383 major = PROTOCOL_MAJOR_1;
384 minor = PROTOCOL_MINOR_1;
386 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
387 server_version_string = xstrdup(buf);
389 /* Send our protocol version identification. */
390 if (atomicio(vwrite, sock_out, server_version_string,
391 strlen(server_version_string))
392 != strlen(server_version_string)) {
393 logit("Could not write ident string to %s", get_remote_ipaddr());
397 /* Read other sides version identification. */
398 memset(buf, 0, sizeof(buf));
399 for (i = 0; i < sizeof(buf) - 1; i++) {
400 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
401 logit("Did not receive identification string from %s",
402 get_remote_ipaddr());
405 if (buf[i] == '\r') {
407 /* Kludge for F-Secure Macintosh < 1.0.2 */
409 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
413 if (buf[i] == '\n') {
418 buf[sizeof(buf) - 1] = 0;
419 client_version_string = xstrdup(buf);
422 * Check that the versions match. In future this might accept
423 * several versions and set appropriate flags to handle them.
425 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
426 &remote_major, &remote_minor, remote_version) != 3) {
427 s = "Protocol mismatch.\n";
428 (void) atomicio(vwrite, sock_out, s, strlen(s));
431 logit("Bad protocol version identification '%.100s' from %s",
432 client_version_string, get_remote_ipaddr());
435 debug("Client protocol version %d.%d; client software version %.100s",
436 remote_major, remote_minor, remote_version);
438 compat_datafellows(remote_version);
440 if (datafellows & SSH_BUG_PROBE) {
441 logit("probed from %s with %s. Don't panic.",
442 get_remote_ipaddr(), client_version_string);
446 if (datafellows & SSH_BUG_SCANNER) {
447 logit("scanned from %s with %s. Don't panic.",
448 get_remote_ipaddr(), client_version_string);
453 switch (remote_major) {
455 if (remote_minor == 99) {
456 if (options.protocol & SSH_PROTO_2)
462 if (!(options.protocol & SSH_PROTO_1)) {
466 if (remote_minor < 3) {
467 packet_disconnect("Your ssh version is too old and "
468 "is no longer supported. Please install a newer version.");
469 } else if (remote_minor == 3) {
470 /* note that this disables agent-forwarding */
475 if (options.protocol & SSH_PROTO_2) {
484 chop(server_version_string);
485 debug("Local version string %.200s", server_version_string);
488 s = "Protocol major versions differ.\n";
489 (void) atomicio(vwrite, sock_out, s, strlen(s));
492 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
494 server_version_string, client_version_string);
499 /* Destroy the host and server keys. They will no longer be needed. */
501 destroy_sensitive_data(void)
505 if (sensitive_data.server_key) {
506 key_free(sensitive_data.server_key);
507 sensitive_data.server_key = NULL;
509 for (i = 0; i < options.num_host_key_files; i++) {
510 if (sensitive_data.host_keys[i]) {
511 key_free(sensitive_data.host_keys[i]);
512 sensitive_data.host_keys[i] = NULL;
515 sensitive_data.ssh1_host_key = NULL;
516 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
519 /* Demote private to public keys for network child */
521 demote_sensitive_data(void)
526 if (sensitive_data.server_key) {
527 tmp = key_demote(sensitive_data.server_key);
528 key_free(sensitive_data.server_key);
529 sensitive_data.server_key = tmp;
532 for (i = 0; i < options.num_host_key_files; i++) {
533 if (sensitive_data.host_keys[i]) {
534 tmp = key_demote(sensitive_data.host_keys[i]);
535 key_free(sensitive_data.host_keys[i]);
536 sensitive_data.host_keys[i] = tmp;
537 if (tmp->type == KEY_RSA1)
538 sensitive_data.ssh1_host_key = tmp;
542 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
546 privsep_preauth_child(void)
553 /* Enable challenge-response authentication for privilege separation */
554 privsep_challenge_enable();
556 for (i = 0; i < 256; i++)
557 rnd[i] = arc4random();
558 RAND_seed(rnd, sizeof(rnd));
560 /* Demote the private keys to public keys. */
561 demote_sensitive_data();
563 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
564 fatal("Privilege separation user %s does not exist",
566 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
569 /* Change our root directory */
570 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
571 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
573 if (chdir("/") == -1)
574 fatal("chdir(\"/\"): %s", strerror(errno));
576 /* Drop our privileges */
577 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
580 /* XXX not ready, to heavy after chroot */
581 do_setusercontext(pw);
583 gidset[0] = pw->pw_gid;
584 if (setgroups(1, gidset) < 0)
585 fatal("setgroups: %.100s", strerror(errno));
586 permanently_set_uid(pw);
591 privsep_preauth(Authctxt *authctxt)
596 /* Set up unprivileged child process to deal with network data */
597 pmonitor = monitor_init();
598 /* Store a pointer to the kex for later rekeying */
599 pmonitor->m_pkex = &xxx_kex;
603 fatal("fork of unprivileged child failed");
604 } else if (pid != 0) {
605 debug2("Network child is on pid %ld", (long)pid);
607 close(pmonitor->m_recvfd);
608 pmonitor->m_pid = pid;
609 monitor_child_preauth(authctxt, pmonitor);
610 close(pmonitor->m_sendfd);
613 monitor_sync(pmonitor);
615 /* Wait for the child's exit status */
616 while (waitpid(pid, &status, 0) < 0)
623 close(pmonitor->m_sendfd);
625 /* Demote the child */
626 if (getuid() == 0 || geteuid() == 0)
627 privsep_preauth_child();
628 setproctitle("%s", "[net]");
634 privsep_postauth(Authctxt *authctxt)
636 #ifdef DISABLE_FD_PASSING
639 if (authctxt->pw->pw_uid == 0 || options.use_login) {
641 /* File descriptor passing is broken or root login */
642 monitor_apply_keystate(pmonitor);
647 /* Authentication complete */
649 if (startup_pipe != -1) {
654 /* New socket pair */
655 monitor_reinit(pmonitor);
657 pmonitor->m_pid = fork();
658 if (pmonitor->m_pid == -1)
659 fatal("fork of unprivileged child failed");
660 else if (pmonitor->m_pid != 0) {
661 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
662 close(pmonitor->m_recvfd);
663 monitor_child_postauth(pmonitor);
669 close(pmonitor->m_sendfd);
671 /* Demote the private keys to public keys. */
672 demote_sensitive_data();
674 /* Drop privileges */
675 do_setusercontext(authctxt->pw);
677 /* It is safe now to apply the key state */
678 monitor_apply_keystate(pmonitor);
682 list_hostkey_types(void)
690 for (i = 0; i < options.num_host_key_files; i++) {
691 Key *key = sensitive_data.host_keys[i];
697 if (buffer_len(&b) > 0)
698 buffer_append(&b, ",", 1);
699 p = key_ssh_name(key);
700 buffer_append(&b, p, strlen(p));
704 buffer_append(&b, "\0", 1);
705 ret = xstrdup(buffer_ptr(&b));
707 debug("list_hostkey_types: %s", ret);
712 get_hostkey_by_type(int type)
716 for (i = 0; i < options.num_host_key_files; i++) {
717 Key *key = sensitive_data.host_keys[i];
718 if (key != NULL && key->type == type)
725 get_hostkey_by_index(int ind)
727 if (ind < 0 || ind >= options.num_host_key_files)
729 return (sensitive_data.host_keys[ind]);
733 get_hostkey_index(Key *key)
737 for (i = 0; i < options.num_host_key_files; i++) {
738 if (key == sensitive_data.host_keys[i])
745 * returns 1 if connection should be dropped, 0 otherwise.
746 * dropping starts at connection #max_startups_begin with a probability
747 * of (max_startups_rate/100). the probability increases linearly until
748 * all connections are dropped for startups > max_startups
751 drop_connection(int startups)
755 if (startups < options.max_startups_begin)
757 if (startups >= options.max_startups)
759 if (options.max_startups_rate == 100)
762 p = 100 - options.max_startups_rate;
763 p *= startups - options.max_startups_begin;
764 p /= (double) (options.max_startups - options.max_startups_begin);
765 p += options.max_startups_rate;
767 r = arc4random() / (double) UINT_MAX;
769 debug("drop_connection: p %g, r %g", p, r);
770 return (r < p) ? 1 : 0;
776 fprintf(stderr, "sshd version %s, %s\n",
777 SSH_VERSION, SSLeay_version(SSLEAY_VERSION));
778 fprintf(stderr, "Usage: %s [options]\n", __progname);
779 fprintf(stderr, "Options:\n");
780 fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
781 fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
782 fprintf(stderr, " -i Started from inetd\n");
783 fprintf(stderr, " -D Do not fork into daemon mode\n");
784 fprintf(stderr, " -t Only test configuration file and keys\n");
785 fprintf(stderr, " -q Quiet (no logging)\n");
786 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
787 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
788 fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
789 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
790 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
791 _PATH_HOST_KEY_FILE);
792 fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
793 fprintf(stderr, " -4 Use IPv4 only\n");
794 fprintf(stderr, " -6 Use IPv6 only\n");
795 fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n");
800 * Main program for the daemon.
803 main(int ac, char **av)
807 int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
811 struct sockaddr_storage from;
812 const char *remote_ip;
816 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
818 int listen_sock, maxfd;
823 int ret, key_used = 0;
825 #ifdef HAVE_SECUREWARE
826 (void)set_auth_parameters(ac, av);
828 __progname = ssh_get_progname(av[0]);
831 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
833 saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1));
834 for (i = 0; i < ac; i++)
835 saved_argv[i] = xstrdup(av[i]);
836 saved_argv[i] = NULL;
838 #ifndef HAVE_SETPROCTITLE
839 /* Prepare for later setproctitle emulation */
840 compat_init_setproctitle(ac, av);
844 /* Initialize configuration options to their default values. */
845 initialize_server_options(&options);
847 /* Parse command-line arguments. */
848 while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqtQ46")) != -1) {
857 config_file_name = optarg;
860 if (debug_flag == 0) {
862 options.log_level = SYSLOG_LEVEL_DEBUG1;
863 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
879 options.log_level = SYSLOG_LEVEL_QUIET;
882 options.server_key_bits = atoi(optarg);
885 options.ports_from_cmdline = 1;
886 if (options.num_ports >= MAX_PORTS) {
887 fprintf(stderr, "too many ports.\n");
890 options.ports[options.num_ports++] = a2port(optarg);
891 if (options.ports[options.num_ports-1] == 0) {
892 fprintf(stderr, "Bad port number.\n");
897 if ((options.login_grace_time = convtime(optarg)) == -1) {
898 fprintf(stderr, "Invalid login grace time.\n");
903 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
904 fprintf(stderr, "Invalid key regeneration interval.\n");
909 if (options.num_host_key_files >= MAX_HOSTKEYS) {
910 fprintf(stderr, "too many host keys.\n");
913 options.host_key_files[options.num_host_key_files++] = optarg;
919 utmp_len = atoi(optarg);
920 if (utmp_len > MAXHOSTNAMELEN) {
921 fprintf(stderr, "Invalid utmp length.\n");
926 line = xstrdup(optarg);
927 if (process_server_config_line(&options, line,
928 "command-line", 0) != 0)
938 SSLeay_add_all_algorithms();
939 channel_set_af(IPv4or6);
942 * Force logging to stderr until we have loaded the private host
943 * key (unless started from inetd)
946 options.log_level == SYSLOG_LEVEL_NOT_SET ?
947 SYSLOG_LEVEL_INFO : options.log_level,
948 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
949 SYSLOG_FACILITY_AUTH : options.log_facility,
950 log_stderr || !inetd_flag);
953 /* Cray can define user privs drop all prives now!
954 * Not needed on PRIV_SU systems!
961 /* Read server configuration options from the configuration file. */
962 read_server_config(&options, config_file_name);
964 /* Fill in default values for those options not explicitly set. */
965 fill_default_server_options(&options);
967 /* Check that there are no remaining arguments. */
969 fprintf(stderr, "Extra argument %s.\n", av[optind]);
973 debug("sshd version %.100s", SSH_VERSION);
975 /* load private host keys */
976 sensitive_data.host_keys = xmalloc(options.num_host_key_files *
978 for (i = 0; i < options.num_host_key_files; i++)
979 sensitive_data.host_keys[i] = NULL;
980 sensitive_data.server_key = NULL;
981 sensitive_data.ssh1_host_key = NULL;
982 sensitive_data.have_ssh1_key = 0;
983 sensitive_data.have_ssh2_key = 0;
985 for (i = 0; i < options.num_host_key_files; i++) {
986 key = key_load_private(options.host_key_files[i], "", NULL);
987 sensitive_data.host_keys[i] = key;
989 error("Could not load host key: %s",
990 options.host_key_files[i]);
991 sensitive_data.host_keys[i] = NULL;
996 sensitive_data.ssh1_host_key = key;
997 sensitive_data.have_ssh1_key = 1;
1001 sensitive_data.have_ssh2_key = 1;
1004 debug("private host key: #%d type %d %s", i, key->type,
1007 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
1008 logit("Disabling protocol version 1. Could not load host key");
1009 options.protocol &= ~SSH_PROTO_1;
1012 /* The GSSAPI key exchange can run without a host key */
1013 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1014 logit("Disabling protocol version 2. Could not load host key");
1015 options.protocol &= ~SSH_PROTO_2;
1018 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1019 logit("sshd: no hostkeys available -- exiting.");
1023 /* Check certain values for sanity. */
1024 if (options.protocol & SSH_PROTO_1) {
1025 if (options.server_key_bits < 512 ||
1026 options.server_key_bits > 32768) {
1027 fprintf(stderr, "Bad server key size.\n");
1031 * Check that server and host key lengths differ sufficiently. This
1032 * is necessary to make double encryption work with rsaref. Oh, I
1033 * hate software patents. I dont know if this can go? Niels
1035 if (options.server_key_bits >
1036 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1037 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1038 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1039 SSH_KEY_BITS_RESERVED) {
1040 options.server_key_bits =
1041 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1042 SSH_KEY_BITS_RESERVED;
1043 debug("Forcing server key to %d bits to make it differ from host key.",
1044 options.server_key_bits);
1052 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1053 fatal("Privilege separation user %s does not exist",
1055 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1056 (S_ISDIR(st.st_mode) == 0))
1057 fatal("Missing privilege separation directory: %s",
1058 _PATH_PRIVSEP_CHROOT_DIR);
1061 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1062 (st.st_uid != getuid () ||
1063 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1065 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1067 fatal("%s must be owned by root and not group or "
1068 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1071 /* Configuration looks good, so exit if in test mode. */
1076 * Clear out any supplemental groups we may have inherited. This
1077 * prevents inadvertent creation of files with bad modes (in the
1078 * portable version at least, it's certainly possible for PAM
1079 * to create a file, and we can't control the code in every
1080 * module which might be used).
1082 if (setgroups(0, NULL) < 0)
1083 debug("setgroups() failed: %.200s", strerror(errno));
1085 /* Initialize the log (it is reinitialized below in case we forked). */
1086 if (debug_flag && !inetd_flag)
1088 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1091 * If not in debugging mode, and not started from inetd, disconnect
1092 * from the controlling terminal, and fork. The original process
1095 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1098 #endif /* TIOCNOTTY */
1099 if (daemon(0, 0) < 0)
1100 fatal("daemon() failed: %.200s", strerror(errno));
1102 /* Disconnect from the controlling tty. */
1104 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
1106 (void) ioctl(fd, TIOCNOTTY, NULL);
1109 #endif /* TIOCNOTTY */
1111 /* Reinitialize the log (because of the fork above). */
1112 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1114 /* Initialize the random number generator. */
1117 /* Chdir to the root directory so that the current disk can be
1118 unmounted if desired. */
1122 /* Clear environment */
1126 /* ignore SIGPIPE */
1127 signal(SIGPIPE, SIG_IGN);
1129 /* Start listening for a socket, unless started from inetd. */
1132 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
1138 * We intentionally do not close the descriptors 0, 1, and 2
1139 * as our code for setting the descriptors won\'t work if
1140 * ttyfd happens to be one of those.
1142 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
1143 if (options.protocol & SSH_PROTO_1)
1144 generate_ephemeral_server_key();
1146 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1147 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1149 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1150 fatal("Too many listen sockets. "
1151 "Enlarge MAX_LISTEN_SOCKS");
1152 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
1153 ntop, sizeof(ntop), strport, sizeof(strport),
1154 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1155 error("getnameinfo failed");
1158 /* Create socket for listening. */
1159 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1161 if (listen_sock < 0) {
1162 /* kernel may not support ipv6 */
1163 verbose("socket: %.100s", strerror(errno));
1166 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
1167 error("listen_sock O_NONBLOCK: %s", strerror(errno));
1172 * Set socket options.
1173 * Allow local port reuse in TIME_WAIT.
1175 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1176 &on, sizeof(on)) == -1)
1177 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1179 debug("Bind to port %s on %s.", strport, ntop);
1181 /* Bind the socket to the desired port. */
1182 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1184 error("Bind to port %s on %s failed: %.200s.",
1185 strport, ntop, strerror(errno));
1189 listen_socks[num_listen_socks] = listen_sock;
1192 /* Start listening on the port. */
1193 logit("Server listening on %s port %s.", ntop, strport);
1194 if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0)
1195 fatal("listen: %.100s", strerror(errno));
1198 freeaddrinfo(options.listen_addrs);
1200 if (!num_listen_socks)
1201 fatal("Cannot bind any address.");
1203 if (options.protocol & SSH_PROTO_1)
1204 generate_ephemeral_server_key();
1207 * Arrange to restart on SIGHUP. The handler needs
1210 signal(SIGHUP, sighup_handler);
1212 signal(SIGTERM, sigterm_handler);
1213 signal(SIGQUIT, sigterm_handler);
1215 /* Arrange SIGCHLD to be caught. */
1216 signal(SIGCHLD, main_sigchld_handler);
1218 /* Write out the pid file after the sigterm handler is setup */
1221 * Record our pid in /var/run/sshd.pid to make it
1222 * easier to kill the correct sshd. We don't want to
1223 * do this before the bind above because the bind will
1224 * fail if there already is a daemon, and this will
1225 * overwrite any old pid in the file.
1227 f = fopen(options.pid_file, "wb");
1229 error("Couldn't create pid file \"%s\": %s",
1230 options.pid_file, strerror(errno));
1232 fprintf(f, "%ld\n", (long) getpid());
1237 /* setup fd set for listen */
1240 for (i = 0; i < num_listen_socks; i++)
1241 if (listen_socks[i] > maxfd)
1242 maxfd = listen_socks[i];
1243 /* pipes connected to unauthenticated childs */
1244 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1245 for (i = 0; i < options.max_startups; i++)
1246 startup_pipes[i] = -1;
1249 * Stay listening for connections until the system crashes or
1250 * the daemon is killed with a signal.
1253 if (received_sighup)
1257 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
1258 fdset = (fd_set *)xmalloc(fdsetsz);
1259 memset(fdset, 0, fdsetsz);
1261 for (i = 0; i < num_listen_socks; i++)
1262 FD_SET(listen_socks[i], fdset);
1263 for (i = 0; i < options.max_startups; i++)
1264 if (startup_pipes[i] != -1)
1265 FD_SET(startup_pipes[i], fdset);
1267 /* Wait in select until there is a connection. */
1268 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1269 if (ret < 0 && errno != EINTR)
1270 error("select: %.100s", strerror(errno));
1271 if (received_sigterm) {
1272 logit("Received signal %d; terminating.",
1273 (int) received_sigterm);
1274 close_listen_socks();
1275 unlink(options.pid_file);
1278 if (key_used && key_do_regen) {
1279 generate_ephemeral_server_key();
1286 for (i = 0; i < options.max_startups; i++)
1287 if (startup_pipes[i] != -1 &&
1288 FD_ISSET(startup_pipes[i], fdset)) {
1290 * the read end of the pipe is ready
1291 * if the child has closed the pipe
1292 * after successful authentication
1293 * or if the child has died
1295 close(startup_pipes[i]);
1296 startup_pipes[i] = -1;
1299 for (i = 0; i < num_listen_socks; i++) {
1300 if (!FD_ISSET(listen_socks[i], fdset))
1302 fromlen = sizeof(from);
1303 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1306 if (errno != EINTR && errno != EWOULDBLOCK)
1307 error("accept: %.100s", strerror(errno));
1310 if (fcntl(newsock, F_SETFL, 0) < 0) {
1311 error("newsock del O_NONBLOCK: %s", strerror(errno));
1315 if (drop_connection(startups) == 1) {
1316 debug("drop connection #%d", startups);
1320 if (pipe(startup_p) == -1) {
1325 for (j = 0; j < options.max_startups; j++)
1326 if (startup_pipes[j] == -1) {
1327 startup_pipes[j] = startup_p[0];
1328 if (maxfd < startup_p[0])
1329 maxfd = startup_p[0];
1335 * Got connection. Fork a child to handle it, unless
1336 * we are in debugging mode.
1340 * In debugging mode. Close the listening
1341 * socket, and start processing the
1342 * connection without forking.
1344 debug("Server will not fork when running in debugging mode.");
1345 close_listen_socks();
1353 * Normal production daemon. Fork, and have
1354 * the child process the connection. The
1355 * parent continues listening.
1357 if ((pid = fork()) == 0) {
1359 * Child. Close the listening and max_startup
1360 * sockets. Start using the accepted socket.
1361 * Reinitialize logging (since our pid has
1362 * changed). We break out of the loop to handle
1365 startup_pipe = startup_p[1];
1366 close_startup_pipes();
1367 close_listen_socks();
1370 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1375 /* Parent. Stay in the loop. */
1377 error("fork: %.100s", strerror(errno));
1379 debug("Forked child %ld.", (long)pid);
1381 close(startup_p[1]);
1383 /* Mark that the key has been used (it was "given" to the child). */
1384 if ((options.protocol & SSH_PROTO_1) &&
1386 /* Schedule server key regeneration alarm. */
1387 signal(SIGALRM, key_regeneration_alarm);
1388 alarm(options.key_regeneration_time);
1394 /* Close the new socket (the child is now taking care of it). */
1397 /* child process check (or debug mode) */
1398 if (num_listen_socks < 0)
1403 /* This is the child processing a new connection. */
1406 * Create a new session and process group since the 4.4BSD
1407 * setlogin() affects the entire process group. We don't
1408 * want the child to be able to affect the parent.
1410 #if !defined(SSHD_ACQUIRES_CTTY)
1412 * If setsid is called, on some platforms sshd will later acquire a
1413 * controlling terminal which will result in "could not set
1414 * controlling tty" errors.
1416 if (!debug_flag && !inetd_flag && setsid() < 0)
1417 error("setsid: %.100s", strerror(errno));
1421 * Disable the key regeneration alarm. We will not regenerate the
1422 * key since we are no longer in a position to give it to anyone. We
1423 * will not restart on SIGHUP since it no longer makes sense.
1426 signal(SIGALRM, SIG_DFL);
1427 signal(SIGHUP, SIG_DFL);
1428 signal(SIGTERM, SIG_DFL);
1429 signal(SIGQUIT, SIG_DFL);
1430 signal(SIGCHLD, SIG_DFL);
1431 signal(SIGINT, SIG_DFL);
1433 /* Set SO_KEEPALIVE if requested. */
1434 if (options.tcp_keep_alive &&
1435 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
1437 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1440 * Register our connection. This turns encryption off because we do
1443 packet_set_connection(sock_in, sock_out);
1445 remote_port = get_remote_port();
1446 remote_ip = get_remote_ipaddr();
1449 /* Check whether logins are denied from this host. */
1451 struct request_info req;
1453 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
1456 if (!hosts_access(&req)) {
1457 debug("Connection refused by tcp wrapper");
1460 fatal("libwrap refuse returns");
1463 #endif /* LIBWRAP */
1465 /* Log the connection. */
1466 verbose("Connection from %.500s port %d", remote_ip, remote_port);
1469 * We don\'t want to listen forever unless the other side
1470 * successfully authenticates itself. So we set up an alarm which is
1471 * cleared after successful authentication. A limit of zero
1472 * indicates no limit. Note that we don\'t set the alarm in debugging
1473 * mode; it is just annoying to have the server exit just when you
1474 * are about to discover the bug.
1476 signal(SIGALRM, grace_alarm_handler);
1478 alarm(options.login_grace_time);
1480 sshd_exchange_identification(sock_in, sock_out);
1481 #if defined(AFS_KRB5)
1482 /* If machine has AFS, set process authentication group. */
1487 #endif /* AFS || AFS_KRB5 */
1489 packet_set_nonblocking();
1491 /* prepare buffers to collect authentication messages */
1492 buffer_init(&loginmsg);
1494 /* allocate authentication context */
1495 authctxt = xmalloc(sizeof(*authctxt));
1496 memset(authctxt, 0, sizeof(*authctxt));
1498 /* XXX global for cleanup, access from other modules */
1499 the_authctxt = authctxt;
1502 if (privsep_preauth(authctxt) == 1)
1505 /* perform the key exchange */
1506 /* authenticate user and start session */
1509 do_authentication2(authctxt);
1512 do_authentication(authctxt);
1515 * If we use privilege separation, the unprivileged child transfers
1516 * the current keystate and exits
1519 mm_send_keystate(pmonitor);
1525 * In privilege separation, we fork another child and prepare
1526 * file descriptor passing.
1529 privsep_postauth(authctxt);
1530 /* the monitor process [priv] will not return */
1532 destroy_sensitive_data();
1535 /* Start session. */
1536 do_authenticated(authctxt);
1538 /* The connection has been terminated. */
1539 verbose("Closing connection to %.100s", remote_ip);
1542 if (options.use_pam)
1544 #endif /* USE_PAM */
1555 * Decrypt session_key_int using our private server key and private host key
1556 * (key with larger modulus first).
1559 ssh1_session_key(BIGNUM *session_key_int)
1563 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1564 /* Server key has bigger modulus. */
1565 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1566 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1567 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1568 get_remote_ipaddr(),
1569 BN_num_bits(sensitive_data.server_key->rsa->n),
1570 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1571 SSH_KEY_BITS_RESERVED);
1573 if (rsa_private_decrypt(session_key_int, session_key_int,
1574 sensitive_data.server_key->rsa) <= 0)
1576 if (rsa_private_decrypt(session_key_int, session_key_int,
1577 sensitive_data.ssh1_host_key->rsa) <= 0)
1580 /* Host key has bigger modulus (or they are equal). */
1581 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1582 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1583 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1584 get_remote_ipaddr(),
1585 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1586 BN_num_bits(sensitive_data.server_key->rsa->n),
1587 SSH_KEY_BITS_RESERVED);
1589 if (rsa_private_decrypt(session_key_int, session_key_int,
1590 sensitive_data.ssh1_host_key->rsa) < 0)
1592 if (rsa_private_decrypt(session_key_int, session_key_int,
1593 sensitive_data.server_key->rsa) < 0)
1606 BIGNUM *session_key_int;
1607 u_char session_key[SSH_SESSION_KEY_LENGTH];
1609 u_int cipher_type, auth_mask, protocol_flags;
1613 * Generate check bytes that the client must send back in the user
1614 * packet in order for it to be accepted; this is used to defy ip
1615 * spoofing attacks. Note that this only works against somebody
1616 * doing IP spoofing from a remote machine; any machine on the local
1617 * network can still see outgoing packets and catch the random
1618 * cookie. This only affects rhosts authentication, and this is one
1619 * of the reasons why it is inherently insecure.
1621 for (i = 0; i < 8; i++) {
1624 cookie[i] = rnd & 0xff;
1629 * Send our public key. We include in the packet 64 bits of random
1630 * data that must be matched in the reply in order to prevent IP
1633 packet_start(SSH_SMSG_PUBLIC_KEY);
1634 for (i = 0; i < 8; i++)
1635 packet_put_char(cookie[i]);
1637 /* Store our public server RSA key. */
1638 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1639 packet_put_bignum(sensitive_data.server_key->rsa->e);
1640 packet_put_bignum(sensitive_data.server_key->rsa->n);
1642 /* Store our public host RSA key. */
1643 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1644 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1645 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
1647 /* Put protocol flags. */
1648 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1650 /* Declare which ciphers we support. */
1651 packet_put_int(cipher_mask_ssh1(0));
1653 /* Declare supported authentication types. */
1655 if (options.rhosts_rsa_authentication)
1656 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1657 if (options.rsa_authentication)
1658 auth_mask |= 1 << SSH_AUTH_RSA;
1659 if (options.challenge_response_authentication == 1)
1660 auth_mask |= 1 << SSH_AUTH_TIS;
1661 if (options.password_authentication)
1662 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1663 packet_put_int(auth_mask);
1665 /* Send the packet and wait for it to be sent. */
1667 packet_write_wait();
1669 debug("Sent %d bit server key and %d bit host key.",
1670 BN_num_bits(sensitive_data.server_key->rsa->n),
1671 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1673 /* Read clients reply (cipher type and session key). */
1674 packet_read_expect(SSH_CMSG_SESSION_KEY);
1676 /* Get cipher type and check whether we accept this. */
1677 cipher_type = packet_get_char();
1679 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1680 packet_disconnect("Warning: client selects unsupported cipher.");
1682 /* Get check bytes from the packet. These must match those we
1683 sent earlier with the public key packet. */
1684 for (i = 0; i < 8; i++)
1685 if (cookie[i] != packet_get_char())
1686 packet_disconnect("IP Spoofing check bytes do not match.");
1688 debug("Encryption type: %.200s", cipher_name(cipher_type));
1690 /* Get the encrypted integer. */
1691 if ((session_key_int = BN_new()) == NULL)
1692 fatal("do_ssh1_kex: BN_new failed");
1693 packet_get_bignum(session_key_int);
1695 protocol_flags = packet_get_int();
1696 packet_set_protocol_flags(protocol_flags);
1699 /* Decrypt session_key_int using host/server keys */
1700 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1703 * Extract session key from the decrypted integer. The key is in the
1704 * least significant 256 bits of the integer; the first byte of the
1705 * key is in the highest bits.
1708 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1709 len = BN_num_bytes(session_key_int);
1710 if (len < 0 || len > sizeof(session_key)) {
1711 error("do_connection: bad session key len from %s: "
1712 "session_key_int %d > sizeof(session_key) %lu",
1713 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
1716 memset(session_key, 0, sizeof(session_key));
1717 BN_bn2bin(session_key_int,
1718 session_key + sizeof(session_key) - len);
1720 compute_session_id(session_id, cookie,
1721 sensitive_data.ssh1_host_key->rsa->n,
1722 sensitive_data.server_key->rsa->n);
1724 * Xor the first 16 bytes of the session key with the
1727 for (i = 0; i < 16; i++)
1728 session_key[i] ^= session_id[i];
1732 int bytes = BN_num_bytes(session_key_int);
1733 u_char *buf = xmalloc(bytes);
1736 logit("do_connection: generating a fake encryption key");
1737 BN_bn2bin(session_key_int, buf);
1739 MD5_Update(&md, buf, bytes);
1740 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1741 MD5_Final(session_key, &md);
1743 MD5_Update(&md, session_key, 16);
1744 MD5_Update(&md, buf, bytes);
1745 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1746 MD5_Final(session_key + 16, &md);
1747 memset(buf, 0, bytes);
1749 for (i = 0; i < 16; i++)
1750 session_id[i] = session_key[i] ^ session_key[i + 16];
1752 /* Destroy the private and public keys. No longer. */
1753 destroy_sensitive_data();
1756 mm_ssh1_session_id(session_id);
1758 /* Destroy the decrypted integer. It is no longer needed. */
1759 BN_clear_free(session_key_int);
1761 /* Set the session key. From this on all communications will be encrypted. */
1762 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1764 /* Destroy our copy of the session key. It is no longer needed. */
1765 memset(session_key, 0, sizeof(session_key));
1767 debug("Received session key; encryption turned on.");
1769 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
1770 packet_start(SSH_SMSG_SUCCESS);
1772 packet_write_wait();
1776 * SSH2 key exchange: diffie-hellman-group1-sha1
1783 if (options.ciphers != NULL) {
1784 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1785 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1787 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1788 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
1789 myproposal[PROPOSAL_ENC_ALGS_STOC] =
1790 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1792 if (options.macs != NULL) {
1793 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1794 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1796 if (!options.compression) {
1797 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1798 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1800 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1806 char *newstr = NULL;
1807 orig = myproposal[PROPOSAL_KEX_ALGS];
1809 /* If we don't have a host key, then all of the algorithms
1810 * currently in myproposal are useless */
1811 if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])==0)
1814 if (options.gss_keyex)
1815 gss = ssh_gssapi_server_mechanisms();
1820 int len = strlen(orig) + strlen(gss) +2;
1821 newstr=xmalloc(len);
1822 snprintf(newstr,len,"%s,%s",gss,orig);
1828 /* If we've got GSSAPI mechanisms, then we've also got the 'null'
1829 host key algorithm, but we're not allowed to advertise it, unless
1830 its the only host key algorithm we're supporting */
1831 if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) {
1832 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]="null";
1835 myproposal[PROPOSAL_KEX_ALGS]=newstr;
1837 fatal("No supported key exchange algorithms");
1841 /* start key exchange */
1842 kex = kex_setup(myproposal);
1843 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1844 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1846 kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
1849 kex->client_version_string=client_version_string;
1850 kex->server_version_string=server_version_string;
1851 kex->load_host_key=&get_hostkey_by_type;
1852 kex->host_key_index=&get_hostkey_index;
1856 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1858 session_id2 = kex->session_id;
1859 session_id2_len = kex->session_id_len;
1862 /* send 1st encrypted/maced/compressed message */
1863 packet_start(SSH2_MSG_IGNORE);
1864 packet_put_cstring("markus");
1866 packet_write_wait();
1871 /* server specific fatal cleanup */
1876 do_cleanup(the_authctxt);