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 1.267 2003/05/29 16:58:45 deraadt 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.
115 int IPv4or6 = AF_UNSPEC;
118 * Debug mode flag. This can be set on the command line. If debug
119 * mode is enabled, extra debugging output will be sent to the system
120 * log, the daemon will not go to background, and will exit after processing
121 * the first connection.
125 /* Flag indicating that the daemon should only test the configuration and keys. */
128 /* Flag indicating that the daemon is being started from inetd. */
131 /* Flag indicating that sshd should not detach and become a daemon. */
132 int no_daemon_flag = 0;
134 /* debug goes to stderr unless inetd_flag is set */
137 /* Saved arguments to main(). */
142 * The sockets that the server is listening; this is used in the SIGHUP
145 #define MAX_LISTEN_SOCKS 16
146 int listen_socks[MAX_LISTEN_SOCKS];
147 int num_listen_socks = 0;
150 * the client's version string, passed by sshd2 in compat mode. if != NULL,
151 * sshd will skip the version-number exchange
153 char *client_version_string = NULL;
154 char *server_version_string = NULL;
156 /* for rekeying XXX fixme */
160 * Any really sensitive data in the application is contained in this
161 * structure. The idea is that this structure could be locked into memory so
162 * that the pages do not get written into swap. However, there are some
163 * problems. The private key contains BIGNUMs, and we do not (in principle)
164 * have access to the internals of them, and locking just the structure is
165 * not very useful. Currently, memory locking is not implemented.
168 Key *server_key; /* ephemeral server key */
169 Key *ssh1_host_key; /* ssh1 host key */
170 Key **host_keys; /* all private host keys */
173 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
177 * Flag indicating whether the RSA server key needs to be regenerated.
178 * Is set in the SIGALRM handler and cleared when the key is regenerated.
180 static volatile sig_atomic_t key_do_regen = 0;
182 /* This is set to true when a signal is received. */
183 static volatile sig_atomic_t received_sighup = 0;
184 static volatile sig_atomic_t received_sigterm = 0;
186 /* session identifier, used by RSA-auth */
187 u_char session_id[16];
190 u_char *session_id2 = NULL;
191 int session_id2_len = 0;
193 /* record remote hostname or ip */
194 u_int utmp_len = MAXHOSTNAMELEN;
196 /* options.max_startup sized array of fd ints */
197 int *startup_pipes = NULL;
198 int startup_pipe; /* in child */
200 /* variables used for privilege separation */
202 struct monitor *pmonitor;
204 /* Prototypes for various functions defined later in this file. */
205 void destroy_sensitive_data(void);
206 void demote_sensitive_data(void);
208 static void do_ssh1_kex(void);
209 static void do_ssh2_kex(void);
212 * Close all listening sockets
215 close_listen_socks(void)
219 for (i = 0; i < num_listen_socks; i++)
220 close(listen_socks[i]);
221 num_listen_socks = -1;
225 close_startup_pipes(void)
230 for (i = 0; i < options.max_startups; i++)
231 if (startup_pipes[i] != -1)
232 close(startup_pipes[i]);
236 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
237 * the effect is to reread the configuration file (and to regenerate
241 sighup_handler(int sig)
243 int save_errno = errno;
246 signal(SIGHUP, sighup_handler);
251 * Called from the main program after receiving SIGHUP.
252 * Restarts the server.
257 logit("Received SIGHUP; restarting.");
258 close_listen_socks();
259 close_startup_pipes();
260 execv(saved_argv[0], saved_argv);
261 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
267 * Generic signal handler for terminating signals in the master daemon.
270 sigterm_handler(int sig)
272 received_sigterm = sig;
276 * SIGCHLD handler. This is called whenever a child dies. This will then
277 * reap any zombies left by exited children.
280 main_sigchld_handler(int sig)
282 int save_errno = errno;
286 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
287 (pid < 0 && errno == EINTR))
290 signal(SIGCHLD, main_sigchld_handler);
295 * Signal handler for the alarm after the login grace period has expired.
298 grace_alarm_handler(int sig)
300 /* XXX no idea how fix this signal handler */
302 /* Log error and exit. */
303 fatal("Timeout before authentication for %s", get_remote_ipaddr());
307 * Signal handler for the key regeneration alarm. Note that this
308 * alarm only occurs in the daemon waiting for connections, and it does not
309 * do anything with the private key or random state before forking.
310 * Thus there should be no concurrency control/asynchronous execution
314 generate_ephemeral_server_key(void)
319 verbose("Generating %s%d bit RSA key.",
320 sensitive_data.server_key ? "new " : "", options.server_key_bits);
321 if (sensitive_data.server_key != NULL)
322 key_free(sensitive_data.server_key);
323 sensitive_data.server_key = key_generate(KEY_RSA1,
324 options.server_key_bits);
325 verbose("RSA key generation complete.");
327 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
330 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
337 key_regeneration_alarm(int sig)
339 int save_errno = errno;
341 signal(SIGALRM, SIG_DFL);
347 sshd_exchange_identification(int sock_in, int sock_out)
350 int remote_major, remote_minor;
353 char buf[256]; /* Must not be larger than remote_version. */
354 char remote_version[256]; /* Must be at least as big as buf. */
356 if ((options.protocol & SSH_PROTO_1) &&
357 (options.protocol & SSH_PROTO_2)) {
358 major = PROTOCOL_MAJOR_1;
360 } else if (options.protocol & SSH_PROTO_2) {
361 major = PROTOCOL_MAJOR_2;
362 minor = PROTOCOL_MINOR_2;
364 major = PROTOCOL_MAJOR_1;
365 minor = PROTOCOL_MINOR_1;
367 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
368 server_version_string = xstrdup(buf);
370 if (client_version_string == NULL) {
371 /* Send our protocol version identification. */
372 if (atomicio(write, sock_out, server_version_string,
373 strlen(server_version_string))
374 != strlen(server_version_string)) {
375 logit("Could not write ident string to %s", get_remote_ipaddr());
379 /* Read other sides version identification. */
380 memset(buf, 0, sizeof(buf));
381 for (i = 0; i < sizeof(buf) - 1; i++) {
382 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
383 logit("Did not receive identification string from %s",
384 get_remote_ipaddr());
387 if (buf[i] == '\r') {
389 /* Kludge for F-Secure Macintosh < 1.0.2 */
391 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
395 if (buf[i] == '\n') {
400 buf[sizeof(buf) - 1] = 0;
401 client_version_string = xstrdup(buf);
405 * Check that the versions match. In future this might accept
406 * several versions and set appropriate flags to handle them.
408 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
409 &remote_major, &remote_minor, remote_version) != 3) {
410 s = "Protocol mismatch.\n";
411 (void) atomicio(write, sock_out, s, strlen(s));
414 logit("Bad protocol version identification '%.100s' from %s",
415 client_version_string, get_remote_ipaddr());
418 debug("Client protocol version %d.%d; client software version %.100s",
419 remote_major, remote_minor, remote_version);
421 compat_datafellows(remote_version);
423 if (datafellows & SSH_BUG_PROBE) {
424 logit("probed from %s with %s. Don't panic.",
425 get_remote_ipaddr(), client_version_string);
429 if (datafellows & SSH_BUG_SCANNER) {
430 logit("scanned from %s with %s. Don't panic.",
431 get_remote_ipaddr(), client_version_string);
436 switch (remote_major) {
438 if (remote_minor == 99) {
439 if (options.protocol & SSH_PROTO_2)
445 if (!(options.protocol & SSH_PROTO_1)) {
449 if (remote_minor < 3) {
450 packet_disconnect("Your ssh version is too old and "
451 "is no longer supported. Please install a newer version.");
452 } else if (remote_minor == 3) {
453 /* note that this disables agent-forwarding */
458 if (options.protocol & SSH_PROTO_2) {
467 chop(server_version_string);
468 debug("Local version string %.200s", server_version_string);
471 s = "Protocol major versions differ.\n";
472 (void) atomicio(write, sock_out, s, strlen(s));
475 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
477 server_version_string, client_version_string);
482 /* Destroy the host and server keys. They will no longer be needed. */
484 destroy_sensitive_data(void)
488 if (sensitive_data.server_key) {
489 key_free(sensitive_data.server_key);
490 sensitive_data.server_key = NULL;
492 for (i = 0; i < options.num_host_key_files; i++) {
493 if (sensitive_data.host_keys[i]) {
494 key_free(sensitive_data.host_keys[i]);
495 sensitive_data.host_keys[i] = NULL;
498 sensitive_data.ssh1_host_key = NULL;
499 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
502 /* Demote private to public keys for network child */
504 demote_sensitive_data(void)
509 if (sensitive_data.server_key) {
510 tmp = key_demote(sensitive_data.server_key);
511 key_free(sensitive_data.server_key);
512 sensitive_data.server_key = tmp;
515 for (i = 0; i < options.num_host_key_files; i++) {
516 if (sensitive_data.host_keys[i]) {
517 tmp = key_demote(sensitive_data.host_keys[i]);
518 key_free(sensitive_data.host_keys[i]);
519 sensitive_data.host_keys[i] = tmp;
520 if (tmp->type == KEY_RSA1)
521 sensitive_data.ssh1_host_key = tmp;
525 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
529 privsep_preauth_child(void)
536 /* Enable challenge-response authentication for privilege separation */
537 privsep_challenge_enable();
539 for (i = 0; i < 256; i++)
540 rnd[i] = arc4random();
541 RAND_seed(rnd, sizeof(rnd));
543 /* Demote the private keys to public keys. */
544 demote_sensitive_data();
546 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
547 fatal("Privilege separation user %s does not exist",
549 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
552 /* Change our root directory */
553 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
554 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
556 if (chdir("/") == -1)
557 fatal("chdir(\"/\"): %s", strerror(errno));
559 /* Drop our privileges */
560 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
563 /* XXX not ready, to heavy after chroot */
564 do_setusercontext(pw);
566 gidset[0] = pw->pw_gid;
567 if (setegid(pw->pw_gid) < 0)
568 fatal("setegid failed for %u", (u_int)pw->pw_gid);
569 if (setgid(pw->pw_gid) < 0)
570 fatal("setgid failed for %u", (u_int)pw->pw_gid);
571 if (setgroups(1, gidset) < 0)
572 fatal("setgroups: %.100s", strerror(errno));
573 permanently_set_uid(pw);
578 privsep_preauth(void)
580 Authctxt *authctxt = NULL;
584 /* Set up unprivileged child process to deal with network data */
585 pmonitor = monitor_init();
586 /* Store a pointer to the kex for later rekeying */
587 pmonitor->m_pkex = &xxx_kex;
591 fatal("fork of unprivileged child failed");
592 } else if (pid != 0) {
593 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
595 debug2("Network child is on pid %ld", (long)pid);
597 close(pmonitor->m_recvfd);
598 authctxt = monitor_child_preauth(pmonitor);
599 close(pmonitor->m_sendfd);
602 monitor_sync(pmonitor);
604 /* Wait for the child's exit status */
605 while (waitpid(pid, &status, 0) < 0)
609 /* Reinstall, since the child has finished */
610 fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
616 close(pmonitor->m_sendfd);
618 /* Demote the child */
619 if (getuid() == 0 || geteuid() == 0)
620 privsep_preauth_child();
621 setproctitle("%s", "[net]");
627 privsep_postauth(Authctxt *authctxt)
629 extern Authctxt *x_authctxt;
631 /* XXX - Remote port forwarding */
632 x_authctxt = authctxt;
634 #ifdef DISABLE_FD_PASSING
637 if (authctxt->pw->pw_uid == 0 || options.use_login) {
639 /* File descriptor passing is broken or root login */
640 monitor_apply_keystate(pmonitor);
645 /* Authentication complete */
647 if (startup_pipe != -1) {
652 /* New socket pair */
653 monitor_reinit(pmonitor);
655 pmonitor->m_pid = fork();
656 if (pmonitor->m_pid == -1)
657 fatal("fork of unprivileged child failed");
658 else if (pmonitor->m_pid != 0) {
659 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
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)
689 for (i = 0; i < options.num_host_key_files; i++) {
690 Key *key = sensitive_data.host_keys[i];
696 if (buffer_len(&b) > 0)
697 buffer_append(&b, ",", 1);
698 p = key_ssh_name(key);
699 buffer_append(&b, p, strlen(p));
703 buffer_append(&b, "\0", 1);
704 p = xstrdup(buffer_ptr(&b));
706 debug("list_hostkey_types: %s", p);
711 get_hostkey_by_type(int type)
715 for (i = 0; i < options.num_host_key_files; i++) {
716 Key *key = sensitive_data.host_keys[i];
717 if (key != NULL && key->type == type)
724 get_hostkey_by_index(int ind)
726 if (ind < 0 || ind >= options.num_host_key_files)
728 return (sensitive_data.host_keys[ind]);
732 get_hostkey_index(Key *key)
736 for (i = 0; i < options.num_host_key_files; i++) {
737 if (key == sensitive_data.host_keys[i])
744 * returns 1 if connection should be dropped, 0 otherwise.
745 * dropping starts at connection #max_startups_begin with a probability
746 * of (max_startups_rate/100). the probability increases linearly until
747 * all connections are dropped for startups > max_startups
750 drop_connection(int startups)
754 if (startups < options.max_startups_begin)
756 if (startups >= options.max_startups)
758 if (options.max_startups_rate == 100)
761 p = 100 - options.max_startups_rate;
762 p *= startups - options.max_startups_begin;
763 p /= (double) (options.max_startups - options.max_startups_begin);
764 p += options.max_startups_rate;
766 r = arc4random() / (double) UINT_MAX;
768 debug("drop_connection: p %g, r %g", p, r);
769 return (r < p) ? 1 : 0;
775 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
776 fprintf(stderr, "Usage: %s [options]\n", __progname);
777 fprintf(stderr, "Options:\n");
778 fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
779 fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
780 fprintf(stderr, " -i Started from inetd\n");
781 fprintf(stderr, " -D Do not fork into daemon mode\n");
782 fprintf(stderr, " -t Only test configuration file and keys\n");
783 fprintf(stderr, " -q Quiet (no logging)\n");
784 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
785 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
786 fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
787 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
788 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
789 _PATH_HOST_KEY_FILE);
790 fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
791 fprintf(stderr, " -4 Use IPv4 only\n");
792 fprintf(stderr, " -6 Use IPv6 only\n");
793 fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n");
798 * Main program for the daemon.
801 main(int ac, char **av)
805 int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
809 struct sockaddr_storage from;
810 const char *remote_ip;
814 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
815 int listen_sock, maxfd;
820 int ret, key_used = 0;
822 #ifdef HAVE_SECUREWARE
823 (void)set_auth_parameters(ac, av);
825 __progname = get_progname(av[0]);
828 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
830 saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1));
831 for (i = 0; i < ac; i++)
832 saved_argv[i] = xstrdup(av[i]);
833 saved_argv[i] = NULL;
835 #ifndef HAVE_SETPROCTITLE
836 /* Prepare for later setproctitle emulation */
837 compat_init_setproctitle(ac, av);
841 /* Initialize configuration options to their default values. */
842 initialize_server_options(&options);
844 /* Parse command-line arguments. */
845 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:o:dDeiqtQ46")) != -1) {
854 config_file_name = optarg;
857 if (0 == debug_flag) {
859 options.log_level = SYSLOG_LEVEL_DEBUG1;
860 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
863 fprintf(stderr, "Too high debugging level.\n");
880 options.log_level = SYSLOG_LEVEL_QUIET;
883 options.server_key_bits = atoi(optarg);
886 options.ports_from_cmdline = 1;
887 if (options.num_ports >= MAX_PORTS) {
888 fprintf(stderr, "too many ports.\n");
891 options.ports[options.num_ports++] = a2port(optarg);
892 if (options.ports[options.num_ports-1] == 0) {
893 fprintf(stderr, "Bad port number.\n");
898 if ((options.login_grace_time = convtime(optarg)) == -1) {
899 fprintf(stderr, "Invalid login grace time.\n");
904 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
905 fprintf(stderr, "Invalid key regeneration interval.\n");
910 if (options.num_host_key_files >= MAX_HOSTKEYS) {
911 fprintf(stderr, "too many host keys.\n");
914 options.host_key_files[options.num_host_key_files++] = optarg;
917 client_version_string = optarg;
918 /* only makes sense with inetd_flag, i.e. no listen() */
925 utmp_len = atoi(optarg);
926 if (utmp_len > MAXHOSTNAMELEN) {
927 fprintf(stderr, "Invalid utmp length.\n");
932 if (process_server_config_line(&options, optarg,
933 "command-line", 0) != 0)
942 SSLeay_add_all_algorithms();
943 channel_set_af(IPv4or6);
946 * Force logging to stderr until we have loaded the private host
947 * key (unless started from inetd)
950 options.log_level == SYSLOG_LEVEL_NOT_SET ?
951 SYSLOG_LEVEL_INFO : options.log_level,
952 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
953 SYSLOG_FACILITY_AUTH : options.log_facility,
954 log_stderr || !inetd_flag);
957 /* Cray can define user privs drop all prives now!
958 * Not needed on PRIV_SU systems!
965 /* Read server configuration options from the configuration file. */
966 read_server_config(&options, config_file_name);
968 /* Fill in default values for those options not explicitly set. */
969 fill_default_server_options(&options);
971 /* Check that there are no remaining arguments. */
973 fprintf(stderr, "Extra argument %s.\n", av[optind]);
977 debug("sshd version %.100s", SSH_VERSION);
979 /* load private host keys */
980 sensitive_data.host_keys = xmalloc(options.num_host_key_files *
982 for (i = 0; i < options.num_host_key_files; i++)
983 sensitive_data.host_keys[i] = NULL;
984 sensitive_data.server_key = NULL;
985 sensitive_data.ssh1_host_key = NULL;
986 sensitive_data.have_ssh1_key = 0;
987 sensitive_data.have_ssh2_key = 0;
989 for (i = 0; i < options.num_host_key_files; i++) {
990 key = key_load_private(options.host_key_files[i], "", NULL);
991 sensitive_data.host_keys[i] = key;
993 error("Could not load host key: %s",
994 options.host_key_files[i]);
995 sensitive_data.host_keys[i] = NULL;
1000 sensitive_data.ssh1_host_key = key;
1001 sensitive_data.have_ssh1_key = 1;
1005 sensitive_data.have_ssh2_key = 1;
1008 debug("private host key: #%d type %d %s", i, key->type,
1011 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
1012 logit("Disabling protocol version 1. Could not load host key");
1013 options.protocol &= ~SSH_PROTO_1;
1015 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1016 logit("Disabling protocol version 2. Could not load host key");
1017 options.protocol &= ~SSH_PROTO_2;
1019 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1020 logit("sshd: no hostkeys available -- exiting.");
1024 /* Check certain values for sanity. */
1025 if (options.protocol & SSH_PROTO_1) {
1026 if (options.server_key_bits < 512 ||
1027 options.server_key_bits > 32768) {
1028 fprintf(stderr, "Bad server key size.\n");
1032 * Check that server and host key lengths differ sufficiently. This
1033 * is necessary to make double encryption work with rsaref. Oh, I
1034 * hate software patents. I dont know if this can go? Niels
1036 if (options.server_key_bits >
1037 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1038 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1039 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1040 SSH_KEY_BITS_RESERVED) {
1041 options.server_key_bits =
1042 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1043 SSH_KEY_BITS_RESERVED;
1044 debug("Forcing server key to %d bits to make it differ from host key.",
1045 options.server_key_bits);
1053 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1054 fatal("Privilege separation user %s does not exist",
1056 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1057 (S_ISDIR(st.st_mode) == 0))
1058 fatal("Missing privilege separation directory: %s",
1059 _PATH_PRIVSEP_CHROOT_DIR);
1062 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1063 (st.st_uid != getuid () ||
1064 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1066 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1068 fatal("%s must be owned by root and not group or "
1069 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1072 /* Configuration looks good, so exit if in test mode. */
1077 * Clear out any supplemental groups we may have inherited. This
1078 * prevents inadvertent creation of files with bad modes (in the
1079 * portable version at least, it's certainly possible for PAM
1080 * to create a file, and we can't control the code in every
1081 * module which might be used).
1083 if (setgroups(0, NULL) < 0)
1084 debug("setgroups() failed: %.200s", strerror(errno));
1086 /* Initialize the log (it is reinitialized below in case we forked). */
1087 if (debug_flag && !inetd_flag)
1089 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1092 * If not in debugging mode, and not started from inetd, disconnect
1093 * from the controlling terminal, and fork. The original process
1096 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1099 #endif /* TIOCNOTTY */
1100 if (daemon(0, 0) < 0)
1101 fatal("daemon() failed: %.200s", strerror(errno));
1103 /* Disconnect from the controlling tty. */
1105 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
1107 (void) ioctl(fd, TIOCNOTTY, NULL);
1110 #endif /* TIOCNOTTY */
1112 /* Reinitialize the log (because of the fork above). */
1113 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1115 /* Initialize the random number generator. */
1118 /* Chdir to the root directory so that the current disk can be
1119 unmounted if desired. */
1122 /* ignore SIGPIPE */
1123 signal(SIGPIPE, SIG_IGN);
1125 /* Start listening for a socket, unless started from inetd. */
1128 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
1134 * We intentionally do not close the descriptors 0, 1, and 2
1135 * as our code for setting the descriptors won\'t work if
1136 * ttyfd happens to be one of those.
1138 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
1139 if (options.protocol & SSH_PROTO_1)
1140 generate_ephemeral_server_key();
1142 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1143 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1145 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1146 fatal("Too many listen sockets. "
1147 "Enlarge MAX_LISTEN_SOCKS");
1148 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
1149 ntop, sizeof(ntop), strport, sizeof(strport),
1150 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1151 error("getnameinfo failed");
1154 /* Create socket for listening. */
1155 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1157 if (listen_sock < 0) {
1158 /* kernel may not support ipv6 */
1159 verbose("socket: %.100s", strerror(errno));
1162 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
1163 error("listen_sock O_NONBLOCK: %s", strerror(errno));
1168 * Set socket options.
1169 * Allow local port reuse in TIME_WAIT.
1171 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1172 &on, sizeof(on)) == -1)
1173 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1175 debug("Bind to port %s on %s.", strport, ntop);
1177 /* Bind the socket to the desired port. */
1178 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1180 error("Bind to port %s on %s failed: %.200s.",
1181 strport, ntop, strerror(errno));
1185 listen_socks[num_listen_socks] = listen_sock;
1188 /* Start listening on the port. */
1189 logit("Server listening on %s port %s.", ntop, strport);
1190 if (listen(listen_sock, 5) < 0)
1191 fatal("listen: %.100s", strerror(errno));
1194 freeaddrinfo(options.listen_addrs);
1196 if (!num_listen_socks)
1197 fatal("Cannot bind any address.");
1199 if (options.protocol & SSH_PROTO_1)
1200 generate_ephemeral_server_key();
1203 * Arrange to restart on SIGHUP. The handler needs
1206 signal(SIGHUP, sighup_handler);
1208 signal(SIGTERM, sigterm_handler);
1209 signal(SIGQUIT, sigterm_handler);
1211 /* Arrange SIGCHLD to be caught. */
1212 signal(SIGCHLD, main_sigchld_handler);
1214 /* Write out the pid file after the sigterm handler is setup */
1217 * Record our pid in /var/run/sshd.pid to make it
1218 * easier to kill the correct sshd. We don't want to
1219 * do this before the bind above because the bind will
1220 * fail if there already is a daemon, and this will
1221 * overwrite any old pid in the file.
1223 f = fopen(options.pid_file, "wb");
1225 fprintf(f, "%ld\n", (long) getpid());
1230 /* setup fd set for listen */
1233 for (i = 0; i < num_listen_socks; i++)
1234 if (listen_socks[i] > maxfd)
1235 maxfd = listen_socks[i];
1236 /* pipes connected to unauthenticated childs */
1237 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1238 for (i = 0; i < options.max_startups; i++)
1239 startup_pipes[i] = -1;
1242 * Stay listening for connections until the system crashes or
1243 * the daemon is killed with a signal.
1246 if (received_sighup)
1250 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
1251 fdset = (fd_set *)xmalloc(fdsetsz);
1252 memset(fdset, 0, fdsetsz);
1254 for (i = 0; i < num_listen_socks; i++)
1255 FD_SET(listen_socks[i], fdset);
1256 for (i = 0; i < options.max_startups; i++)
1257 if (startup_pipes[i] != -1)
1258 FD_SET(startup_pipes[i], fdset);
1260 /* Wait in select until there is a connection. */
1261 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1262 if (ret < 0 && errno != EINTR)
1263 error("select: %.100s", strerror(errno));
1264 if (received_sigterm) {
1265 logit("Received signal %d; terminating.",
1266 (int) received_sigterm);
1267 close_listen_socks();
1268 unlink(options.pid_file);
1271 if (key_used && key_do_regen) {
1272 generate_ephemeral_server_key();
1279 for (i = 0; i < options.max_startups; i++)
1280 if (startup_pipes[i] != -1 &&
1281 FD_ISSET(startup_pipes[i], fdset)) {
1283 * the read end of the pipe is ready
1284 * if the child has closed the pipe
1285 * after successful authentication
1286 * or if the child has died
1288 close(startup_pipes[i]);
1289 startup_pipes[i] = -1;
1292 for (i = 0; i < num_listen_socks; i++) {
1293 if (!FD_ISSET(listen_socks[i], fdset))
1295 fromlen = sizeof(from);
1296 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1299 if (errno != EINTR && errno != EWOULDBLOCK)
1300 error("accept: %.100s", strerror(errno));
1303 if (fcntl(newsock, F_SETFL, 0) < 0) {
1304 error("newsock del O_NONBLOCK: %s", strerror(errno));
1308 if (drop_connection(startups) == 1) {
1309 debug("drop connection #%d", startups);
1313 if (pipe(startup_p) == -1) {
1318 for (j = 0; j < options.max_startups; j++)
1319 if (startup_pipes[j] == -1) {
1320 startup_pipes[j] = startup_p[0];
1321 if (maxfd < startup_p[0])
1322 maxfd = startup_p[0];
1328 * Got connection. Fork a child to handle it, unless
1329 * we are in debugging mode.
1333 * In debugging mode. Close the listening
1334 * socket, and start processing the
1335 * connection without forking.
1337 debug("Server will not fork when running in debugging mode.");
1338 close_listen_socks();
1346 * Normal production daemon. Fork, and have
1347 * the child process the connection. The
1348 * parent continues listening.
1350 if ((pid = fork()) == 0) {
1352 * Child. Close the listening and max_startup
1353 * sockets. Start using the accepted socket.
1354 * Reinitialize logging (since our pid has
1355 * changed). We break out of the loop to handle
1358 startup_pipe = startup_p[1];
1359 close_startup_pipes();
1360 close_listen_socks();
1363 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1368 /* Parent. Stay in the loop. */
1370 error("fork: %.100s", strerror(errno));
1372 debug("Forked child %ld.", (long)pid);
1374 close(startup_p[1]);
1376 /* Mark that the key has been used (it was "given" to the child). */
1377 if ((options.protocol & SSH_PROTO_1) &&
1379 /* Schedule server key regeneration alarm. */
1380 signal(SIGALRM, key_regeneration_alarm);
1381 alarm(options.key_regeneration_time);
1387 /* Close the new socket (the child is now taking care of it). */
1390 /* child process check (or debug mode) */
1391 if (num_listen_socks < 0)
1396 /* This is the child processing a new connection. */
1399 * Create a new session and process group since the 4.4BSD
1400 * setlogin() affects the entire process group. We don't
1401 * want the child to be able to affect the parent.
1403 #if !defined(SSHD_ACQUIRES_CTTY)
1405 * If setsid is called, on some platforms sshd will later acquire a
1406 * controlling terminal which will result in "could not set
1407 * controlling tty" errors.
1409 if (!debug_flag && !inetd_flag && setsid() < 0)
1410 error("setsid: %.100s", strerror(errno));
1414 * Disable the key regeneration alarm. We will not regenerate the
1415 * key since we are no longer in a position to give it to anyone. We
1416 * will not restart on SIGHUP since it no longer makes sense.
1419 signal(SIGALRM, SIG_DFL);
1420 signal(SIGHUP, SIG_DFL);
1421 signal(SIGTERM, SIG_DFL);
1422 signal(SIGQUIT, SIG_DFL);
1423 signal(SIGCHLD, SIG_DFL);
1424 signal(SIGINT, SIG_DFL);
1426 /* Set keepalives if requested. */
1427 if (options.keepalives &&
1428 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
1430 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1433 * Register our connection. This turns encryption off because we do
1436 packet_set_connection(sock_in, sock_out);
1438 remote_port = get_remote_port();
1439 remote_ip = get_remote_ipaddr();
1442 /* Check whether logins are denied from this host. */
1444 struct request_info req;
1446 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
1449 if (!hosts_access(&req)) {
1450 debug("Connection refused by tcp wrapper");
1453 fatal("libwrap refuse returns");
1456 #endif /* LIBWRAP */
1458 /* Log the connection. */
1459 verbose("Connection from %.500s port %d", remote_ip, remote_port);
1462 * We don\'t want to listen forever unless the other side
1463 * successfully authenticates itself. So we set up an alarm which is
1464 * cleared after successful authentication. A limit of zero
1465 * indicates no limit. Note that we don\'t set the alarm in debugging
1466 * mode; it is just annoying to have the server exit just when you
1467 * are about to discover the bug.
1469 signal(SIGALRM, grace_alarm_handler);
1471 alarm(options.login_grace_time);
1473 sshd_exchange_identification(sock_in, sock_out);
1475 * Check that the connection comes from a privileged port.
1476 * Rhosts-Authentication only makes sense from privileged
1477 * programs. Of course, if the intruder has root access on his local
1478 * machine, he can connect from any port. So do not use these
1479 * authentication methods from machines that you do not trust.
1481 if (options.rhosts_authentication &&
1482 (remote_port >= IPPORT_RESERVED ||
1483 remote_port < IPPORT_RESERVED / 2)) {
1484 debug("Rhosts Authentication disabled, "
1485 "originating port %d not trusted.", remote_port);
1486 options.rhosts_authentication = 0;
1488 #if defined(KRB4) && !defined(KRB5)
1489 if (!packet_connection_is_ipv4() &&
1490 options.kerberos_authentication) {
1491 debug("Kerberos Authentication disabled, only available for IPv4.");
1492 options.kerberos_authentication = 0;
1494 #endif /* KRB4 && !KRB5 */
1496 /* If machine has AFS, set process authentication group. */
1503 packet_set_nonblocking();
1506 if ((authctxt = privsep_preauth()) != NULL)
1509 /* perform the key exchange */
1510 /* authenticate user and start session */
1513 authctxt = do_authentication2();
1516 authctxt = do_authentication();
1519 * If we use privilege separation, the unprivileged child transfers
1520 * the current keystate and exits
1523 mm_send_keystate(pmonitor);
1529 * In privilege separation, we fork another child and prepare
1530 * file descriptor passing.
1533 privsep_postauth(authctxt);
1534 /* the monitor process [priv] will not return */
1536 destroy_sensitive_data();
1539 /* Perform session preparation. */
1540 do_authenticated(authctxt);
1542 /* The connection has been terminated. */
1543 verbose("Closing connection to %.100s", remote_ip);
1546 if (options.use_pam)
1548 #endif /* USE_PAM */
1559 * Decrypt session_key_int using our private server key and private host key
1560 * (key with larger modulus first).
1563 ssh1_session_key(BIGNUM *session_key_int)
1567 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1568 /* Server key has bigger modulus. */
1569 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1570 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1571 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1572 get_remote_ipaddr(),
1573 BN_num_bits(sensitive_data.server_key->rsa->n),
1574 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1575 SSH_KEY_BITS_RESERVED);
1577 if (rsa_private_decrypt(session_key_int, session_key_int,
1578 sensitive_data.server_key->rsa) <= 0)
1580 if (rsa_private_decrypt(session_key_int, session_key_int,
1581 sensitive_data.ssh1_host_key->rsa) <= 0)
1584 /* Host key has bigger modulus (or they are equal). */
1585 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1586 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1587 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1588 get_remote_ipaddr(),
1589 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1590 BN_num_bits(sensitive_data.server_key->rsa->n),
1591 SSH_KEY_BITS_RESERVED);
1593 if (rsa_private_decrypt(session_key_int, session_key_int,
1594 sensitive_data.ssh1_host_key->rsa) < 0)
1596 if (rsa_private_decrypt(session_key_int, session_key_int,
1597 sensitive_data.server_key->rsa) < 0)
1610 BIGNUM *session_key_int;
1611 u_char session_key[SSH_SESSION_KEY_LENGTH];
1613 u_int cipher_type, auth_mask, protocol_flags;
1617 * Generate check bytes that the client must send back in the user
1618 * packet in order for it to be accepted; this is used to defy ip
1619 * spoofing attacks. Note that this only works against somebody
1620 * doing IP spoofing from a remote machine; any machine on the local
1621 * network can still see outgoing packets and catch the random
1622 * cookie. This only affects rhosts authentication, and this is one
1623 * of the reasons why it is inherently insecure.
1625 for (i = 0; i < 8; i++) {
1628 cookie[i] = rnd & 0xff;
1633 * Send our public key. We include in the packet 64 bits of random
1634 * data that must be matched in the reply in order to prevent IP
1637 packet_start(SSH_SMSG_PUBLIC_KEY);
1638 for (i = 0; i < 8; i++)
1639 packet_put_char(cookie[i]);
1641 /* Store our public server RSA key. */
1642 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1643 packet_put_bignum(sensitive_data.server_key->rsa->e);
1644 packet_put_bignum(sensitive_data.server_key->rsa->n);
1646 /* Store our public host RSA key. */
1647 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1648 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1649 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
1651 /* Put protocol flags. */
1652 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1654 /* Declare which ciphers we support. */
1655 packet_put_int(cipher_mask_ssh1(0));
1657 /* Declare supported authentication types. */
1659 if (options.rhosts_authentication)
1660 auth_mask |= 1 << SSH_AUTH_RHOSTS;
1661 if (options.rhosts_rsa_authentication)
1662 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1663 if (options.rsa_authentication)
1664 auth_mask |= 1 << SSH_AUTH_RSA;
1665 #if defined(KRB4) || defined(KRB5)
1666 if (options.kerberos_authentication)
1667 auth_mask |= 1 << SSH_AUTH_KERBEROS;
1669 #if defined(AFS) || defined(KRB5)
1670 if (options.kerberos_tgt_passing)
1671 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
1674 if (options.afs_token_passing)
1675 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
1677 if (options.challenge_response_authentication == 1)
1678 auth_mask |= 1 << SSH_AUTH_TIS;
1679 if (options.password_authentication)
1680 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1681 packet_put_int(auth_mask);
1683 /* Send the packet and wait for it to be sent. */
1685 packet_write_wait();
1687 debug("Sent %d bit server key and %d bit host key.",
1688 BN_num_bits(sensitive_data.server_key->rsa->n),
1689 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1691 /* Read clients reply (cipher type and session key). */
1692 packet_read_expect(SSH_CMSG_SESSION_KEY);
1694 /* Get cipher type and check whether we accept this. */
1695 cipher_type = packet_get_char();
1697 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1698 packet_disconnect("Warning: client selects unsupported cipher.");
1700 /* Get check bytes from the packet. These must match those we
1701 sent earlier with the public key packet. */
1702 for (i = 0; i < 8; i++)
1703 if (cookie[i] != packet_get_char())
1704 packet_disconnect("IP Spoofing check bytes do not match.");
1706 debug("Encryption type: %.200s", cipher_name(cipher_type));
1708 /* Get the encrypted integer. */
1709 if ((session_key_int = BN_new()) == NULL)
1710 fatal("do_ssh1_kex: BN_new failed");
1711 packet_get_bignum(session_key_int);
1713 protocol_flags = packet_get_int();
1714 packet_set_protocol_flags(protocol_flags);
1717 /* Decrypt session_key_int using host/server keys */
1718 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1721 * Extract session key from the decrypted integer. The key is in the
1722 * least significant 256 bits of the integer; the first byte of the
1723 * key is in the highest bits.
1726 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1727 len = BN_num_bytes(session_key_int);
1728 if (len < 0 || len > sizeof(session_key)) {
1729 error("do_connection: bad session key len from %s: "
1730 "session_key_int %d > sizeof(session_key) %lu",
1731 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
1734 memset(session_key, 0, sizeof(session_key));
1735 BN_bn2bin(session_key_int,
1736 session_key + sizeof(session_key) - len);
1738 compute_session_id(session_id, cookie,
1739 sensitive_data.ssh1_host_key->rsa->n,
1740 sensitive_data.server_key->rsa->n);
1742 * Xor the first 16 bytes of the session key with the
1745 for (i = 0; i < 16; i++)
1746 session_key[i] ^= session_id[i];
1750 int bytes = BN_num_bytes(session_key_int);
1751 u_char *buf = xmalloc(bytes);
1754 logit("do_connection: generating a fake encryption key");
1755 BN_bn2bin(session_key_int, buf);
1757 MD5_Update(&md, buf, bytes);
1758 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1759 MD5_Final(session_key, &md);
1761 MD5_Update(&md, session_key, 16);
1762 MD5_Update(&md, buf, bytes);
1763 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1764 MD5_Final(session_key + 16, &md);
1765 memset(buf, 0, bytes);
1767 for (i = 0; i < 16; i++)
1768 session_id[i] = session_key[i] ^ session_key[i + 16];
1770 /* Destroy the private and public keys. No longer. */
1771 destroy_sensitive_data();
1774 mm_ssh1_session_id(session_id);
1776 /* Destroy the decrypted integer. It is no longer needed. */
1777 BN_clear_free(session_key_int);
1779 /* Set the session key. From this on all communications will be encrypted. */
1780 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1782 /* Destroy our copy of the session key. It is no longer needed. */
1783 memset(session_key, 0, sizeof(session_key));
1785 debug("Received session key; encryption turned on.");
1787 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
1788 packet_start(SSH_SMSG_SUCCESS);
1790 packet_write_wait();
1794 * SSH2 key exchange: diffie-hellman-group1-sha1
1801 if (options.ciphers != NULL) {
1802 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1803 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1805 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1806 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
1807 myproposal[PROPOSAL_ENC_ALGS_STOC] =
1808 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1810 if (options.macs != NULL) {
1811 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1812 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1814 if (!options.compression) {
1815 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1816 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1818 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1820 /* start key exchange */
1821 kex = kex_setup(myproposal);
1822 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1823 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1825 kex->client_version_string=client_version_string;
1826 kex->server_version_string=server_version_string;
1827 kex->load_host_key=&get_hostkey_by_type;
1828 kex->host_key_index=&get_hostkey_index;
1832 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1834 session_id2 = kex->session_id;
1835 session_id2_len = kex->session_id_len;
1838 /* send 1st encrypted/maced/compressed message */
1839 packet_start(SSH2_MSG_IGNORE);
1840 packet_put_cstring("markus");
1842 packet_write_wait();