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 1.256 2002/07/19 15:43:33 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"
91 int allow_severity = LOG_INFO;
92 int deny_severity = LOG_WARNING;
99 #ifdef HAVE___PROGNAME
100 extern char *__progname;
105 /* Server configuration options. */
106 ServerOptions options;
108 /* Name of the server configuration file. */
109 char *config_file_name = _PATH_SERVER_CONFIG_FILE;
112 * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
113 * Default value is AF_UNSPEC means both IPv4 and IPv6.
116 int IPv4or6 = AF_INET;
118 int IPv4or6 = AF_UNSPEC;
122 * Debug mode flag. This can be set on the command line. If debug
123 * mode is enabled, extra debugging output will be sent to the system
124 * log, the daemon will not go to background, and will exit after processing
125 * the first connection.
129 /* Flag indicating that the daemon should only test the configuration and keys. */
132 /* Flag indicating that the daemon is being started from inetd. */
135 /* Flag indicating that sshd should not detach and become a daemon. */
136 int no_daemon_flag = 0;
138 /* debug goes to stderr unless inetd_flag is set */
141 /* Saved arguments to main(). */
146 * The sockets that the server is listening; this is used in the SIGHUP
149 #define MAX_LISTEN_SOCKS 16
150 int listen_socks[MAX_LISTEN_SOCKS];
151 int num_listen_socks = 0;
154 * the client's version string, passed by sshd2 in compat mode. if != NULL,
155 * sshd will skip the version-number exchange
157 char *client_version_string = NULL;
158 char *server_version_string = NULL;
160 /* for rekeying XXX fixme */
164 * Any really sensitive data in the application is contained in this
165 * structure. The idea is that this structure could be locked into memory so
166 * that the pages do not get written into swap. However, there are some
167 * problems. The private key contains BIGNUMs, and we do not (in principle)
168 * have access to the internals of them, and locking just the structure is
169 * not very useful. Currently, memory locking is not implemented.
172 Key *server_key; /* ephemeral server key */
173 Key *ssh1_host_key; /* ssh1 host key */
174 Key **host_keys; /* all private host keys */
177 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
181 * Flag indicating whether the RSA server key needs to be regenerated.
182 * Is set in the SIGALRM handler and cleared when the key is regenerated.
184 static volatile sig_atomic_t key_do_regen = 0;
186 /* This is set to true when a signal is received. */
187 static volatile sig_atomic_t received_sighup = 0;
188 static volatile sig_atomic_t received_sigterm = 0;
190 /* session identifier, used by RSA-auth */
191 u_char session_id[16];
194 u_char *session_id2 = NULL;
195 int session_id2_len = 0;
197 /* record remote hostname or ip */
198 u_int utmp_len = MAXHOSTNAMELEN;
200 /* options.max_startup sized array of fd ints */
201 int *startup_pipes = NULL;
202 int startup_pipe; /* in child */
204 /* variables used for privilege separation */
205 extern struct monitor *pmonitor;
206 extern int use_privsep;
208 /* Prototypes for various functions defined later in this file. */
209 void destroy_sensitive_data(void);
210 void demote_sensitive_data(void);
212 static void do_ssh1_kex(void);
213 static void do_ssh2_kex(void);
216 * Close all listening sockets
219 close_listen_socks(void)
223 for (i = 0; i < num_listen_socks; i++)
224 close(listen_socks[i]);
225 num_listen_socks = -1;
229 close_startup_pipes(void)
234 for (i = 0; i < options.max_startups; i++)
235 if (startup_pipes[i] != -1)
236 close(startup_pipes[i]);
240 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
241 * the effect is to reread the configuration file (and to regenerate
245 sighup_handler(int sig)
247 int save_errno = errno;
250 signal(SIGHUP, sighup_handler);
255 * Called from the main program after receiving SIGHUP.
256 * Restarts the server.
261 log("Received SIGHUP; restarting.");
262 close_listen_socks();
263 close_startup_pipes();
264 execv(saved_argv[0], saved_argv);
265 log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
271 * Generic signal handler for terminating signals in the master daemon.
274 sigterm_handler(int sig)
276 received_sigterm = sig;
280 * SIGCHLD handler. This is called whenever a child dies. This will then
281 * reap any zombies left by exited children.
284 main_sigchld_handler(int sig)
286 int save_errno = errno;
290 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
291 (pid < 0 && errno == EINTR))
294 signal(SIGCHLD, main_sigchld_handler);
299 * Signal handler for the alarm after the login grace period has expired.
302 grace_alarm_handler(int sig)
304 /* XXX no idea how fix this signal handler */
306 /* Log error and exit. */
307 fatal("Timeout before authentication for %s.", get_remote_ipaddr());
311 * Signal handler for the key regeneration alarm. Note that this
312 * alarm only occurs in the daemon waiting for connections, and it does not
313 * do anything with the private key or random state before forking.
314 * Thus there should be no concurrency control/asynchronous execution
318 generate_ephemeral_server_key(void)
323 verbose("Generating %s%d bit RSA key.",
324 sensitive_data.server_key ? "new " : "", options.server_key_bits);
325 if (sensitive_data.server_key != NULL)
326 key_free(sensitive_data.server_key);
327 sensitive_data.server_key = key_generate(KEY_RSA1,
328 options.server_key_bits);
329 verbose("RSA key generation complete.");
331 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
334 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
341 key_regeneration_alarm(int sig)
343 int save_errno = errno;
345 signal(SIGALRM, SIG_DFL);
351 sshd_exchange_identification(int sock_in, int sock_out)
354 int remote_major, remote_minor;
357 char buf[256]; /* Must not be larger than remote_version. */
358 char remote_version[256]; /* Must be at least as big as buf. */
360 if ((options.protocol & SSH_PROTO_1) &&
361 (options.protocol & SSH_PROTO_2)) {
362 major = PROTOCOL_MAJOR_1;
364 } else if (options.protocol & SSH_PROTO_2) {
365 major = PROTOCOL_MAJOR_2;
366 minor = PROTOCOL_MINOR_2;
368 major = PROTOCOL_MAJOR_1;
369 minor = PROTOCOL_MINOR_1;
371 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
372 server_version_string = xstrdup(buf);
374 if (client_version_string == NULL) {
375 /* Send our protocol version identification. */
376 if (atomicio(write, sock_out, server_version_string,
377 strlen(server_version_string))
378 != strlen(server_version_string)) {
379 log("Could not write ident string to %s", get_remote_ipaddr());
383 /* Read other sides version identification. */
384 memset(buf, 0, sizeof(buf));
385 for (i = 0; i < sizeof(buf) - 1; i++) {
386 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
387 log("Did not receive identification string from %s",
388 get_remote_ipaddr());
391 if (buf[i] == '\r') {
393 /* Kludge for F-Secure Macintosh < 1.0.2 */
395 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
399 if (buf[i] == '\n') {
404 buf[sizeof(buf) - 1] = 0;
405 client_version_string = xstrdup(buf);
409 * Check that the versions match. In future this might accept
410 * several versions and set appropriate flags to handle them.
412 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
413 &remote_major, &remote_minor, remote_version) != 3) {
414 s = "Protocol mismatch.\n";
415 (void) atomicio(write, sock_out, s, strlen(s));
418 log("Bad protocol version identification '%.100s' from %s",
419 client_version_string, get_remote_ipaddr());
422 debug("Client protocol version %d.%d; client software version %.100s",
423 remote_major, remote_minor, remote_version);
425 compat_datafellows(remote_version);
427 if (datafellows & SSH_BUG_SCANNER) {
428 log("scanned from %s with %s. Don't panic.",
429 get_remote_ipaddr(), client_version_string);
434 switch (remote_major) {
436 if (remote_minor == 99) {
437 if (options.protocol & SSH_PROTO_2)
443 if (!(options.protocol & SSH_PROTO_1)) {
447 if (remote_minor < 3) {
448 packet_disconnect("Your ssh version is too old and "
449 "is no longer supported. Please install a newer version.");
450 } else if (remote_minor == 3) {
451 /* note that this disables agent-forwarding */
456 if (options.protocol & SSH_PROTO_2) {
465 chop(server_version_string);
466 debug("Local version string %.200s", server_version_string);
469 s = "Protocol major versions differ.\n";
470 (void) atomicio(write, sock_out, s, strlen(s));
473 log("Protocol major versions differ for %s: %.200s vs. %.200s",
475 server_version_string, client_version_string);
480 /* Destroy the host and server keys. They will no longer be needed. */
482 destroy_sensitive_data(void)
486 if (sensitive_data.server_key) {
487 key_free(sensitive_data.server_key);
488 sensitive_data.server_key = NULL;
490 for (i = 0; i < options.num_host_key_files; i++) {
491 if (sensitive_data.host_keys[i]) {
492 key_free(sensitive_data.host_keys[i]);
493 sensitive_data.host_keys[i] = NULL;
496 sensitive_data.ssh1_host_key = NULL;
497 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
500 /* Demote private to public keys for network child */
502 demote_sensitive_data(void)
507 if (sensitive_data.server_key) {
508 tmp = key_demote(sensitive_data.server_key);
509 key_free(sensitive_data.server_key);
510 sensitive_data.server_key = tmp;
513 for (i = 0; i < options.num_host_key_files; i++) {
514 if (sensitive_data.host_keys[i]) {
515 tmp = key_demote(sensitive_data.host_keys[i]);
516 key_free(sensitive_data.host_keys[i]);
517 sensitive_data.host_keys[i] = tmp;
518 if (tmp->type == KEY_RSA1)
519 sensitive_data.ssh1_host_key = tmp;
523 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
527 privsep_preauth_child(void)
534 /* Enable challenge-response authentication for privilege separation */
535 privsep_challenge_enable();
537 for (i = 0; i < 256; i++)
538 rnd[i] = arc4random();
539 RAND_seed(rnd, sizeof(rnd));
541 /* Demote the private keys to public keys. */
542 demote_sensitive_data();
544 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
545 fatal("Privilege separation user %s does not exist",
547 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
550 /* Change our root directory */
551 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
552 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
554 if (chdir("/") == -1)
555 fatal("chdir(\"/\"): %s", strerror(errno));
557 /* Drop our privileges */
558 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
561 /* XXX not ready, to heavy after chroot */
562 do_setusercontext(pw);
564 gidset[0] = pw->pw_gid;
565 if (setgid(pw->pw_gid) < 0)
566 fatal("setgid failed for %u", pw->pw_gid );
567 if (setgroups(1, gidset) < 0)
568 fatal("setgroups: %.100s", strerror(errno));
569 permanently_set_uid(pw);
574 privsep_preauth(void)
576 Authctxt *authctxt = NULL;
580 /* Set up unprivileged child process to deal with network data */
581 pmonitor = monitor_init();
582 /* Store a pointer to the kex for later rekeying */
583 pmonitor->m_pkex = &xxx_kex;
587 fatal("fork of unprivileged child failed");
588 } else if (pid != 0) {
589 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
591 debug2("Network child is on pid %ld", (long)pid);
593 close(pmonitor->m_recvfd);
594 authctxt = monitor_child_preauth(pmonitor);
595 close(pmonitor->m_sendfd);
598 monitor_sync(pmonitor);
600 /* Wait for the child's exit status */
601 while (waitpid(pid, &status, 0) < 0)
605 /* Reinstall, since the child has finished */
606 fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
612 close(pmonitor->m_sendfd);
614 /* Demote the child */
615 if (getuid() == 0 || geteuid() == 0)
616 privsep_preauth_child();
617 setproctitle("%s", "[net]");
623 privsep_postauth(Authctxt *authctxt)
625 extern Authctxt *x_authctxt;
627 /* XXX - Remote port forwarding */
628 x_authctxt = authctxt;
630 #ifdef DISABLE_FD_PASSING
633 if (authctxt->pw->pw_uid == 0 || options.use_login) {
635 /* File descriptor passing is broken or root login */
636 monitor_apply_keystate(pmonitor);
641 /* Authentication complete */
643 if (startup_pipe != -1) {
648 /* New socket pair */
649 monitor_reinit(pmonitor);
651 pmonitor->m_pid = fork();
652 if (pmonitor->m_pid == -1)
653 fatal("fork of unprivileged child failed");
654 else if (pmonitor->m_pid != 0) {
655 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
657 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
658 close(pmonitor->m_recvfd);
659 monitor_child_postauth(pmonitor);
665 close(pmonitor->m_sendfd);
667 /* Demote the private keys to public keys. */
668 demote_sensitive_data();
670 /* Drop privileges */
671 do_setusercontext(authctxt->pw);
673 /* It is safe now to apply the key state */
674 monitor_apply_keystate(pmonitor);
678 list_hostkey_types(void)
685 for (i = 0; i < options.num_host_key_files; i++) {
686 Key *key = sensitive_data.host_keys[i];
692 if (buffer_len(&b) > 0)
693 buffer_append(&b, ",", 1);
694 p = key_ssh_name(key);
695 buffer_append(&b, p, strlen(p));
699 buffer_append(&b, "\0", 1);
700 p = xstrdup(buffer_ptr(&b));
702 debug("list_hostkey_types: %s", p);
707 get_hostkey_by_type(int type)
711 for (i = 0; i < options.num_host_key_files; i++) {
712 Key *key = sensitive_data.host_keys[i];
713 if (key != NULL && key->type == type)
720 get_hostkey_by_index(int ind)
722 if (ind < 0 || ind >= options.num_host_key_files)
724 return (sensitive_data.host_keys[ind]);
728 get_hostkey_index(Key *key)
732 for (i = 0; i < options.num_host_key_files; i++) {
733 if (key == sensitive_data.host_keys[i])
740 * returns 1 if connection should be dropped, 0 otherwise.
741 * dropping starts at connection #max_startups_begin with a probability
742 * of (max_startups_rate/100). the probability increases linearly until
743 * all connections are dropped for startups > max_startups
746 drop_connection(int startups)
750 if (startups < options.max_startups_begin)
752 if (startups >= options.max_startups)
754 if (options.max_startups_rate == 100)
757 p = 100 - options.max_startups_rate;
758 p *= startups - options.max_startups_begin;
759 p /= (double) (options.max_startups - options.max_startups_begin);
760 p += options.max_startups_rate;
762 r = arc4random() / (double) UINT_MAX;
764 debug("drop_connection: p %g, r %g", p, r);
765 return (r < p) ? 1 : 0;
771 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
772 fprintf(stderr, "Usage: %s [options]\n", __progname);
773 fprintf(stderr, "Options:\n");
774 fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
775 fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
776 fprintf(stderr, " -i Started from inetd\n");
777 fprintf(stderr, " -D Do not fork into daemon mode\n");
778 fprintf(stderr, " -t Only test configuration file and keys\n");
779 fprintf(stderr, " -q Quiet (no logging)\n");
780 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
781 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
782 fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
783 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
784 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
785 _PATH_HOST_KEY_FILE);
786 fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
787 fprintf(stderr, " -4 Use IPv4 only\n");
788 fprintf(stderr, " -6 Use IPv6 only\n");
789 fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n");
794 * Main program for the daemon.
797 main(int ac, char **av)
801 int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
805 struct sockaddr_storage from;
806 const char *remote_ip;
809 struct linger linger;
811 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
812 int listen_sock, maxfd;
817 int ret, key_used = 0;
819 #ifdef HAVE_SECUREWARE
820 (void)set_auth_parameters(ac, av);
822 __progname = get_progname(av[0]);
829 /* Initialize configuration options to their default values. */
830 initialize_server_options(&options);
832 /* Parse command-line arguments. */
833 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:o:dDeiqtQ46")) != -1) {
842 config_file_name = optarg;
845 if (0 == debug_flag) {
847 options.log_level = SYSLOG_LEVEL_DEBUG1;
848 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
851 fprintf(stderr, "Too high debugging level.\n");
868 options.log_level = SYSLOG_LEVEL_QUIET;
871 options.server_key_bits = atoi(optarg);
874 options.ports_from_cmdline = 1;
875 if (options.num_ports >= MAX_PORTS) {
876 fprintf(stderr, "too many ports.\n");
879 options.ports[options.num_ports++] = a2port(optarg);
880 if (options.ports[options.num_ports-1] == 0) {
881 fprintf(stderr, "Bad port number.\n");
886 if ((options.login_grace_time = convtime(optarg)) == -1) {
887 fprintf(stderr, "Invalid login grace time.\n");
892 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
893 fprintf(stderr, "Invalid key regeneration interval.\n");
898 if (options.num_host_key_files >= MAX_HOSTKEYS) {
899 fprintf(stderr, "too many host keys.\n");
902 options.host_key_files[options.num_host_key_files++] = optarg;
905 client_version_string = optarg;
906 /* only makes sense with inetd_flag, i.e. no listen() */
913 utmp_len = atoi(optarg);
914 if (utmp_len < 0 || utmp_len > MAXHOSTNAMELEN)
918 if (process_server_config_line(&options, optarg,
919 "command-line", 0) != 0)
928 SSLeay_add_all_algorithms();
929 channel_set_af(IPv4or6);
932 * Force logging to stderr until we have loaded the private host
933 * key (unless started from inetd)
936 options.log_level == SYSLOG_LEVEL_NOT_SET ?
937 SYSLOG_LEVEL_INFO : options.log_level,
938 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
939 SYSLOG_FACILITY_AUTH : options.log_facility,
942 #if defined(_CRAY) && !defined(_CRAYSV2)
943 /* Cray can define user privs drop all prives now!
944 * Not needed on PRIV_SU systems!
951 /* Read server configuration options from the configuration file. */
952 read_server_config(&options, config_file_name);
954 /* Fill in default values for those options not explicitly set. */
955 fill_default_server_options(&options);
957 /* Check that there are no remaining arguments. */
959 fprintf(stderr, "Extra argument %s.\n", av[optind]);
963 debug("sshd version %.100s", SSH_VERSION);
965 /* load private host keys */
966 sensitive_data.host_keys = xmalloc(options.num_host_key_files *
968 for (i = 0; i < options.num_host_key_files; i++)
969 sensitive_data.host_keys[i] = NULL;
970 sensitive_data.server_key = NULL;
971 sensitive_data.ssh1_host_key = NULL;
972 sensitive_data.have_ssh1_key = 0;
973 sensitive_data.have_ssh2_key = 0;
975 for (i = 0; i < options.num_host_key_files; i++) {
976 key = key_load_private(options.host_key_files[i], "", NULL);
977 sensitive_data.host_keys[i] = key;
979 error("Could not load host key: %s",
980 options.host_key_files[i]);
981 sensitive_data.host_keys[i] = NULL;
986 sensitive_data.ssh1_host_key = key;
987 sensitive_data.have_ssh1_key = 1;
991 sensitive_data.have_ssh2_key = 1;
994 debug("private host key: #%d type %d %s", i, key->type,
997 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
998 log("Disabling protocol version 1. Could not load host key");
999 options.protocol &= ~SSH_PROTO_1;
1001 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1002 log("Disabling protocol version 2. Could not load host key");
1003 options.protocol &= ~SSH_PROTO_2;
1005 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1006 log("sshd: no hostkeys available -- exiting.");
1010 /* Check certain values for sanity. */
1011 if (options.protocol & SSH_PROTO_1) {
1012 if (options.server_key_bits < 512 ||
1013 options.server_key_bits > 32768) {
1014 fprintf(stderr, "Bad server key size.\n");
1018 * Check that server and host key lengths differ sufficiently. This
1019 * is necessary to make double encryption work with rsaref. Oh, I
1020 * hate software patents. I dont know if this can go? Niels
1022 if (options.server_key_bits >
1023 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1024 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1025 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1026 SSH_KEY_BITS_RESERVED) {
1027 options.server_key_bits =
1028 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1029 SSH_KEY_BITS_RESERVED;
1030 debug("Forcing server key to %d bits to make it differ from host key.",
1031 options.server_key_bits);
1039 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1040 fatal("Privilege separation user %s does not exist",
1042 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1043 (S_ISDIR(st.st_mode) == 0))
1044 fatal("Missing privilege separation directory: %s",
1045 _PATH_PRIVSEP_CHROOT_DIR);
1048 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1049 (st.st_uid != getuid () ||
1050 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1052 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1054 fatal("Bad owner or mode for %s",
1055 _PATH_PRIVSEP_CHROOT_DIR);
1058 /* Configuration looks good, so exit if in test mode. */
1063 * Clear out any supplemental groups we may have inherited. This
1064 * prevents inadvertent creation of files with bad modes (in the
1065 * portable version at least, it's certainly possible for PAM
1066 * to create a file, and we can't control the code in every
1067 * module which might be used).
1069 if (setgroups(0, NULL) < 0)
1070 debug("setgroups() failed: %.200s", strerror(errno));
1072 /* Initialize the log (it is reinitialized below in case we forked). */
1073 if (debug_flag && !inetd_flag)
1075 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1078 * If not in debugging mode, and not started from inetd, disconnect
1079 * from the controlling terminal, and fork. The original process
1082 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1085 #endif /* TIOCNOTTY */
1086 if (daemon(0, 0) < 0)
1087 fatal("daemon() failed: %.200s", strerror(errno));
1089 /* Disconnect from the controlling tty. */
1091 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
1093 (void) ioctl(fd, TIOCNOTTY, NULL);
1096 #endif /* TIOCNOTTY */
1098 /* Reinitialize the log (because of the fork above). */
1099 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1101 /* Initialize the random number generator. */
1104 /* Chdir to the root directory so that the current disk can be
1105 unmounted if desired. */
1108 /* ignore SIGPIPE */
1109 signal(SIGPIPE, SIG_IGN);
1111 /* Start listening for a socket, unless started from inetd. */
1114 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
1120 * We intentionally do not close the descriptors 0, 1, and 2
1121 * as our code for setting the descriptors won\'t work if
1122 * ttyfd happens to be one of those.
1124 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
1125 if (options.protocol & SSH_PROTO_1)
1126 generate_ephemeral_server_key();
1128 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1129 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1131 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1132 fatal("Too many listen sockets. "
1133 "Enlarge MAX_LISTEN_SOCKS");
1134 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
1135 ntop, sizeof(ntop), strport, sizeof(strport),
1136 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1137 error("getnameinfo failed");
1140 /* Create socket for listening. */
1141 listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
1142 if (listen_sock < 0) {
1143 /* kernel may not support ipv6 */
1144 verbose("socket: %.100s", strerror(errno));
1147 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
1148 error("listen_sock O_NONBLOCK: %s", strerror(errno));
1153 * Set socket options. We try to make the port
1154 * reusable and have it close as fast as possible
1155 * without waiting in unnecessary wait states on
1158 setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1161 linger.l_linger = 5;
1162 setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
1163 &linger, sizeof(linger));
1165 debug("Bind to port %s on %s.", strport, ntop);
1167 /* Bind the socket to the desired port. */
1168 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1170 error("Bind to port %s on %s failed: %.200s.",
1171 strport, ntop, strerror(errno));
1175 listen_socks[num_listen_socks] = listen_sock;
1178 /* Start listening on the port. */
1179 log("Server listening on %s port %s.", ntop, strport);
1180 if (listen(listen_sock, 5) < 0)
1181 fatal("listen: %.100s", strerror(errno));
1184 freeaddrinfo(options.listen_addrs);
1186 if (!num_listen_socks)
1187 fatal("Cannot bind any address.");
1189 if (options.protocol & SSH_PROTO_1)
1190 generate_ephemeral_server_key();
1193 * Arrange to restart on SIGHUP. The handler needs
1196 signal(SIGHUP, sighup_handler);
1198 signal(SIGTERM, sigterm_handler);
1199 signal(SIGQUIT, sigterm_handler);
1201 /* Arrange SIGCHLD to be caught. */
1202 signal(SIGCHLD, main_sigchld_handler);
1204 /* Write out the pid file after the sigterm handler is setup */
1207 * Record our pid in /var/run/sshd.pid to make it
1208 * easier to kill the correct sshd. We don't want to
1209 * do this before the bind above because the bind will
1210 * fail if there already is a daemon, and this will
1211 * overwrite any old pid in the file.
1213 f = fopen(options.pid_file, "wb");
1215 fprintf(f, "%ld\n", (long) getpid());
1220 /* setup fd set for listen */
1223 for (i = 0; i < num_listen_socks; i++)
1224 if (listen_socks[i] > maxfd)
1225 maxfd = listen_socks[i];
1226 /* pipes connected to unauthenticated childs */
1227 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1228 for (i = 0; i < options.max_startups; i++)
1229 startup_pipes[i] = -1;
1232 * Stay listening for connections until the system crashes or
1233 * the daemon is killed with a signal.
1236 if (received_sighup)
1240 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
1241 fdset = (fd_set *)xmalloc(fdsetsz);
1242 memset(fdset, 0, fdsetsz);
1244 for (i = 0; i < num_listen_socks; i++)
1245 FD_SET(listen_socks[i], fdset);
1246 for (i = 0; i < options.max_startups; i++)
1247 if (startup_pipes[i] != -1)
1248 FD_SET(startup_pipes[i], fdset);
1250 /* Wait in select until there is a connection. */
1251 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1252 if (ret < 0 && errno != EINTR)
1253 error("select: %.100s", strerror(errno));
1254 if (received_sigterm) {
1255 log("Received signal %d; terminating.",
1256 (int) received_sigterm);
1257 close_listen_socks();
1258 unlink(options.pid_file);
1261 if (key_used && key_do_regen) {
1262 generate_ephemeral_server_key();
1269 for (i = 0; i < options.max_startups; i++)
1270 if (startup_pipes[i] != -1 &&
1271 FD_ISSET(startup_pipes[i], fdset)) {
1273 * the read end of the pipe is ready
1274 * if the child has closed the pipe
1275 * after successful authentication
1276 * or if the child has died
1278 close(startup_pipes[i]);
1279 startup_pipes[i] = -1;
1282 for (i = 0; i < num_listen_socks; i++) {
1283 if (!FD_ISSET(listen_socks[i], fdset))
1285 fromlen = sizeof(from);
1286 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1289 if (errno != EINTR && errno != EWOULDBLOCK)
1290 error("accept: %.100s", strerror(errno));
1293 if (fcntl(newsock, F_SETFL, 0) < 0) {
1294 error("newsock del O_NONBLOCK: %s", strerror(errno));
1298 if (drop_connection(startups) == 1) {
1299 debug("drop connection #%d", startups);
1303 if (pipe(startup_p) == -1) {
1308 for (j = 0; j < options.max_startups; j++)
1309 if (startup_pipes[j] == -1) {
1310 startup_pipes[j] = startup_p[0];
1311 if (maxfd < startup_p[0])
1312 maxfd = startup_p[0];
1318 * Got connection. Fork a child to handle it, unless
1319 * we are in debugging mode.
1323 * In debugging mode. Close the listening
1324 * socket, and start processing the
1325 * connection without forking.
1327 debug("Server will not fork when running in debugging mode.");
1328 close_listen_socks();
1336 * Normal production daemon. Fork, and have
1337 * the child process the connection. The
1338 * parent continues listening.
1340 if ((pid = fork()) == 0) {
1342 * Child. Close the listening and max_startup
1343 * sockets. Start using the accepted socket.
1344 * Reinitialize logging (since our pid has
1345 * changed). We break out of the loop to handle
1348 startup_pipe = startup_p[1];
1349 close_startup_pipes();
1350 close_listen_socks();
1353 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1358 /* Parent. Stay in the loop. */
1360 error("fork: %.100s", strerror(errno));
1362 debug("Forked child %ld.", (long)pid);
1364 close(startup_p[1]);
1366 /* Mark that the key has been used (it was "given" to the child). */
1367 if ((options.protocol & SSH_PROTO_1) &&
1369 /* Schedule server key regeneration alarm. */
1370 signal(SIGALRM, key_regeneration_alarm);
1371 alarm(options.key_regeneration_time);
1377 /* Close the new socket (the child is now taking care of it). */
1380 /* child process check (or debug mode) */
1381 if (num_listen_socks < 0)
1386 /* This is the child processing a new connection. */
1389 * Create a new session and process group since the 4.4BSD
1390 * setlogin() affects the entire process group. We don't
1391 * want the child to be able to affect the parent.
1394 /* XXX: this breaks Solaris */
1395 if (!debug_flag && !inetd_flag && setsid() < 0)
1396 error("setsid: %.100s", strerror(errno));
1400 * Disable the key regeneration alarm. We will not regenerate the
1401 * key since we are no longer in a position to give it to anyone. We
1402 * will not restart on SIGHUP since it no longer makes sense.
1405 signal(SIGALRM, SIG_DFL);
1406 signal(SIGHUP, SIG_DFL);
1407 signal(SIGTERM, SIG_DFL);
1408 signal(SIGQUIT, SIG_DFL);
1409 signal(SIGCHLD, SIG_DFL);
1410 signal(SIGINT, SIG_DFL);
1413 * Set socket options for the connection. We want the socket to
1414 * close as fast as possible without waiting for anything. If the
1415 * connection is not a socket, these will do nothing.
1417 /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
1419 linger.l_linger = 5;
1420 setsockopt(sock_in, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
1422 /* Set keepalives if requested. */
1423 if (options.keepalives &&
1424 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
1426 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1429 * Register our connection. This turns encryption off because we do
1432 packet_set_connection(sock_in, sock_out);
1434 remote_port = get_remote_port();
1435 remote_ip = get_remote_ipaddr();
1438 /* Check whether logins are denied from this host. */
1440 struct request_info req;
1442 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
1445 if (!hosts_access(&req)) {
1446 debug("Connection refused by tcp wrapper");
1449 fatal("libwrap refuse returns");
1452 #endif /* LIBWRAP */
1454 /* Log the connection. */
1455 verbose("Connection from %.500s port %d", remote_ip, remote_port);
1458 * We don\'t want to listen forever unless the other side
1459 * successfully authenticates itself. So we set up an alarm which is
1460 * cleared after successful authentication. A limit of zero
1461 * indicates no limit. Note that we don\'t set the alarm in debugging
1462 * mode; it is just annoying to have the server exit just when you
1463 * are about to discover the bug.
1465 signal(SIGALRM, grace_alarm_handler);
1467 alarm(options.login_grace_time);
1469 sshd_exchange_identification(sock_in, sock_out);
1471 * Check that the connection comes from a privileged port.
1472 * Rhosts-Authentication only makes sense from privileged
1473 * programs. Of course, if the intruder has root access on his local
1474 * machine, he can connect from any port. So do not use these
1475 * authentication methods from machines that you do not trust.
1477 if (options.rhosts_authentication &&
1478 (remote_port >= IPPORT_RESERVED ||
1479 remote_port < IPPORT_RESERVED / 2)) {
1480 debug("Rhosts Authentication disabled, "
1481 "originating port %d not trusted.", remote_port);
1482 options.rhosts_authentication = 0;
1484 #if defined(KRB4) && !defined(KRB5)
1485 if (!packet_connection_is_ipv4() &&
1486 options.kerberos_authentication) {
1487 debug("Kerberos Authentication disabled, only available for IPv4.");
1488 options.kerberos_authentication = 0;
1490 #endif /* KRB4 && !KRB5 */
1492 /* If machine has AFS, set process authentication group. */
1499 packet_set_nonblocking();
1502 if ((authctxt = privsep_preauth()) != NULL)
1505 /* perform the key exchange */
1506 /* authenticate user and start session */
1509 authctxt = do_authentication2();
1512 authctxt = do_authentication();
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 /* Perform session preparation. */
1536 do_authenticated(authctxt);
1538 /* The connection has been terminated. */
1539 verbose("Closing connection to %.100s", remote_ip);
1543 #endif /* USE_PAM */
1554 * Decrypt session_key_int using our private server key and private host key
1555 * (key with larger modulus first).
1558 ssh1_session_key(BIGNUM *session_key_int)
1562 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1563 /* Server key has bigger modulus. */
1564 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1565 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1566 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1567 get_remote_ipaddr(),
1568 BN_num_bits(sensitive_data.server_key->rsa->n),
1569 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1570 SSH_KEY_BITS_RESERVED);
1572 if (rsa_private_decrypt(session_key_int, session_key_int,
1573 sensitive_data.server_key->rsa) <= 0)
1575 if (rsa_private_decrypt(session_key_int, session_key_int,
1576 sensitive_data.ssh1_host_key->rsa) <= 0)
1579 /* Host key has bigger modulus (or they are equal). */
1580 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1581 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1582 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1583 get_remote_ipaddr(),
1584 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1585 BN_num_bits(sensitive_data.server_key->rsa->n),
1586 SSH_KEY_BITS_RESERVED);
1588 if (rsa_private_decrypt(session_key_int, session_key_int,
1589 sensitive_data.ssh1_host_key->rsa) < 0)
1591 if (rsa_private_decrypt(session_key_int, session_key_int,
1592 sensitive_data.server_key->rsa) < 0)
1605 BIGNUM *session_key_int;
1606 u_char session_key[SSH_SESSION_KEY_LENGTH];
1608 u_int cipher_type, auth_mask, protocol_flags;
1612 * Generate check bytes that the client must send back in the user
1613 * packet in order for it to be accepted; this is used to defy ip
1614 * spoofing attacks. Note that this only works against somebody
1615 * doing IP spoofing from a remote machine; any machine on the local
1616 * network can still see outgoing packets and catch the random
1617 * cookie. This only affects rhosts authentication, and this is one
1618 * of the reasons why it is inherently insecure.
1620 for (i = 0; i < 8; i++) {
1623 cookie[i] = rnd & 0xff;
1628 * Send our public key. We include in the packet 64 bits of random
1629 * data that must be matched in the reply in order to prevent IP
1632 packet_start(SSH_SMSG_PUBLIC_KEY);
1633 for (i = 0; i < 8; i++)
1634 packet_put_char(cookie[i]);
1636 /* Store our public server RSA key. */
1637 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1638 packet_put_bignum(sensitive_data.server_key->rsa->e);
1639 packet_put_bignum(sensitive_data.server_key->rsa->n);
1641 /* Store our public host RSA key. */
1642 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1643 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1644 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
1646 /* Put protocol flags. */
1647 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1649 /* Declare which ciphers we support. */
1650 packet_put_int(cipher_mask_ssh1(0));
1652 /* Declare supported authentication types. */
1654 if (options.rhosts_authentication)
1655 auth_mask |= 1 << SSH_AUTH_RHOSTS;
1656 if (options.rhosts_rsa_authentication)
1657 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1658 if (options.rsa_authentication)
1659 auth_mask |= 1 << SSH_AUTH_RSA;
1660 #if defined(KRB4) || defined(KRB5)
1661 if (options.kerberos_authentication)
1662 auth_mask |= 1 << SSH_AUTH_KERBEROS;
1664 #if defined(AFS) || defined(KRB5)
1665 if (options.kerberos_tgt_passing)
1666 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
1669 if (options.afs_token_passing)
1670 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
1672 if (options.challenge_response_authentication == 1)
1673 auth_mask |= 1 << SSH_AUTH_TIS;
1674 if (options.password_authentication)
1675 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1676 packet_put_int(auth_mask);
1678 /* Send the packet and wait for it to be sent. */
1680 packet_write_wait();
1682 debug("Sent %d bit server key and %d bit host key.",
1683 BN_num_bits(sensitive_data.server_key->rsa->n),
1684 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1686 /* Read clients reply (cipher type and session key). */
1687 packet_read_expect(SSH_CMSG_SESSION_KEY);
1689 /* Get cipher type and check whether we accept this. */
1690 cipher_type = packet_get_char();
1692 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1693 packet_disconnect("Warning: client selects unsupported cipher.");
1695 /* Get check bytes from the packet. These must match those we
1696 sent earlier with the public key packet. */
1697 for (i = 0; i < 8; i++)
1698 if (cookie[i] != packet_get_char())
1699 packet_disconnect("IP Spoofing check bytes do not match.");
1701 debug("Encryption type: %.200s", cipher_name(cipher_type));
1703 /* Get the encrypted integer. */
1704 if ((session_key_int = BN_new()) == NULL)
1705 fatal("do_ssh1_kex: BN_new failed");
1706 packet_get_bignum(session_key_int);
1708 protocol_flags = packet_get_int();
1709 packet_set_protocol_flags(protocol_flags);
1712 /* Decrypt session_key_int using host/server keys */
1713 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1716 * Extract session key from the decrypted integer. The key is in the
1717 * least significant 256 bits of the integer; the first byte of the
1718 * key is in the highest bits.
1721 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1722 len = BN_num_bytes(session_key_int);
1723 if (len < 0 || len > sizeof(session_key)) {
1724 error("do_connection: bad session key len from %s: "
1725 "session_key_int %d > sizeof(session_key) %lu",
1726 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
1729 memset(session_key, 0, sizeof(session_key));
1730 BN_bn2bin(session_key_int,
1731 session_key + sizeof(session_key) - len);
1733 compute_session_id(session_id, cookie,
1734 sensitive_data.ssh1_host_key->rsa->n,
1735 sensitive_data.server_key->rsa->n);
1737 * Xor the first 16 bytes of the session key with the
1740 for (i = 0; i < 16; i++)
1741 session_key[i] ^= session_id[i];
1745 int bytes = BN_num_bytes(session_key_int);
1746 u_char *buf = xmalloc(bytes);
1749 log("do_connection: generating a fake encryption key");
1750 BN_bn2bin(session_key_int, buf);
1752 MD5_Update(&md, buf, bytes);
1753 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1754 MD5_Final(session_key, &md);
1756 MD5_Update(&md, session_key, 16);
1757 MD5_Update(&md, buf, bytes);
1758 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1759 MD5_Final(session_key + 16, &md);
1760 memset(buf, 0, bytes);
1762 for (i = 0; i < 16; i++)
1763 session_id[i] = session_key[i] ^ session_key[i + 16];
1765 /* Destroy the private and public keys. No longer. */
1766 destroy_sensitive_data();
1769 mm_ssh1_session_id(session_id);
1771 /* Destroy the decrypted integer. It is no longer needed. */
1772 BN_clear_free(session_key_int);
1774 /* Set the session key. From this on all communications will be encrypted. */
1775 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1777 /* Destroy our copy of the session key. It is no longer needed. */
1778 memset(session_key, 0, sizeof(session_key));
1780 debug("Received session key; encryption turned on.");
1782 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
1783 packet_start(SSH_SMSG_SUCCESS);
1785 packet_write_wait();
1789 * SSH2 key exchange: diffie-hellman-group1-sha1
1796 if (options.ciphers != NULL) {
1797 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1798 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1800 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1801 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
1802 myproposal[PROPOSAL_ENC_ALGS_STOC] =
1803 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1805 if (options.macs != NULL) {
1806 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1807 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1809 if (!options.compression) {
1810 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1811 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1813 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1815 /* start key exchange */
1816 kex = kex_setup(myproposal);
1818 kex->client_version_string=client_version_string;
1819 kex->server_version_string=server_version_string;
1820 kex->load_host_key=&get_hostkey_by_type;
1821 kex->host_key_index=&get_hostkey_index;
1825 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1827 session_id2 = kex->session_id;
1828 session_id2_len = kex->session_id_len;
1831 /* send 1st encrypted/maced/compressed message */
1832 packet_start(SSH2_MSG_IGNORE);
1833 packet_put_cstring("markus");
1835 packet_write_wait();