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 1.271 2003/06/28 16:23:06 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 u_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 /* message to be displayed after login */
207 /* Prototypes for various functions defined later in this file. */
208 void destroy_sensitive_data(void);
209 void demote_sensitive_data(void);
211 static void do_ssh1_kex(void);
212 static void do_ssh2_kex(void);
215 * Close all listening sockets
218 close_listen_socks(void)
222 for (i = 0; i < num_listen_socks; i++)
223 close(listen_socks[i]);
224 num_listen_socks = -1;
228 close_startup_pipes(void)
233 for (i = 0; i < options.max_startups; i++)
234 if (startup_pipes[i] != -1)
235 close(startup_pipes[i]);
239 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
240 * the effect is to reread the configuration file (and to regenerate
244 sighup_handler(int sig)
246 int save_errno = errno;
249 signal(SIGHUP, sighup_handler);
254 * Called from the main program after receiving SIGHUP.
255 * Restarts the server.
260 logit("Received SIGHUP; restarting.");
261 close_listen_socks();
262 close_startup_pipes();
263 execv(saved_argv[0], saved_argv);
264 logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
270 * Generic signal handler for terminating signals in the master daemon.
273 sigterm_handler(int sig)
275 received_sigterm = sig;
279 * SIGCHLD handler. This is called whenever a child dies. This will then
280 * reap any zombies left by exited children.
283 main_sigchld_handler(int sig)
285 int save_errno = errno;
289 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
290 (pid < 0 && errno == EINTR))
293 signal(SIGCHLD, main_sigchld_handler);
298 * Signal handler for the alarm after the login grace period has expired.
301 grace_alarm_handler(int sig)
303 /* XXX no idea how fix this signal handler */
305 /* Log error and exit. */
306 fatal("Timeout before authentication for %s", get_remote_ipaddr());
310 * Signal handler for the key regeneration alarm. Note that this
311 * alarm only occurs in the daemon waiting for connections, and it does not
312 * do anything with the private key or random state before forking.
313 * Thus there should be no concurrency control/asynchronous execution
317 generate_ephemeral_server_key(void)
322 verbose("Generating %s%d bit RSA key.",
323 sensitive_data.server_key ? "new " : "", options.server_key_bits);
324 if (sensitive_data.server_key != NULL)
325 key_free(sensitive_data.server_key);
326 sensitive_data.server_key = key_generate(KEY_RSA1,
327 options.server_key_bits);
328 verbose("RSA key generation complete.");
330 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
333 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
340 key_regeneration_alarm(int sig)
342 int save_errno = errno;
344 signal(SIGALRM, SIG_DFL);
350 sshd_exchange_identification(int sock_in, int sock_out)
353 int remote_major, remote_minor;
356 char buf[256]; /* Must not be larger than remote_version. */
357 char remote_version[256]; /* Must be at least as big as buf. */
359 if ((options.protocol & SSH_PROTO_1) &&
360 (options.protocol & SSH_PROTO_2)) {
361 major = PROTOCOL_MAJOR_1;
363 } else if (options.protocol & SSH_PROTO_2) {
364 major = PROTOCOL_MAJOR_2;
365 minor = PROTOCOL_MINOR_2;
367 major = PROTOCOL_MAJOR_1;
368 minor = PROTOCOL_MINOR_1;
370 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
371 server_version_string = xstrdup(buf);
373 if (client_version_string == NULL) {
374 /* Send our protocol version identification. */
375 if (atomicio(vwrite, sock_out, server_version_string,
376 strlen(server_version_string))
377 != strlen(server_version_string)) {
378 logit("Could not write ident string to %s", get_remote_ipaddr());
382 /* Read other sides version identification. */
383 memset(buf, 0, sizeof(buf));
384 for (i = 0; i < sizeof(buf) - 1; i++) {
385 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
386 logit("Did not receive identification string from %s",
387 get_remote_ipaddr());
390 if (buf[i] == '\r') {
392 /* Kludge for F-Secure Macintosh < 1.0.2 */
394 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
398 if (buf[i] == '\n') {
403 buf[sizeof(buf) - 1] = 0;
404 client_version_string = xstrdup(buf);
408 * Check that the versions match. In future this might accept
409 * several versions and set appropriate flags to handle them.
411 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
412 &remote_major, &remote_minor, remote_version) != 3) {
413 s = "Protocol mismatch.\n";
414 (void) atomicio(vwrite, sock_out, s, strlen(s));
417 logit("Bad protocol version identification '%.100s' from %s",
418 client_version_string, get_remote_ipaddr());
421 debug("Client protocol version %d.%d; client software version %.100s",
422 remote_major, remote_minor, remote_version);
424 compat_datafellows(remote_version);
426 if (datafellows & SSH_BUG_PROBE) {
427 logit("probed from %s with %s. Don't panic.",
428 get_remote_ipaddr(), client_version_string);
432 if (datafellows & SSH_BUG_SCANNER) {
433 logit("scanned from %s with %s. Don't panic.",
434 get_remote_ipaddr(), client_version_string);
439 switch (remote_major) {
441 if (remote_minor == 99) {
442 if (options.protocol & SSH_PROTO_2)
448 if (!(options.protocol & SSH_PROTO_1)) {
452 if (remote_minor < 3) {
453 packet_disconnect("Your ssh version is too old and "
454 "is no longer supported. Please install a newer version.");
455 } else if (remote_minor == 3) {
456 /* note that this disables agent-forwarding */
461 if (options.protocol & SSH_PROTO_2) {
470 chop(server_version_string);
471 debug("Local version string %.200s", server_version_string);
474 s = "Protocol major versions differ.\n";
475 (void) atomicio(vwrite, sock_out, s, strlen(s));
478 logit("Protocol major versions differ for %s: %.200s vs. %.200s",
480 server_version_string, client_version_string);
485 /* Destroy the host and server keys. They will no longer be needed. */
487 destroy_sensitive_data(void)
491 if (sensitive_data.server_key) {
492 key_free(sensitive_data.server_key);
493 sensitive_data.server_key = NULL;
495 for (i = 0; i < options.num_host_key_files; i++) {
496 if (sensitive_data.host_keys[i]) {
497 key_free(sensitive_data.host_keys[i]);
498 sensitive_data.host_keys[i] = NULL;
501 sensitive_data.ssh1_host_key = NULL;
502 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
505 /* Demote private to public keys for network child */
507 demote_sensitive_data(void)
512 if (sensitive_data.server_key) {
513 tmp = key_demote(sensitive_data.server_key);
514 key_free(sensitive_data.server_key);
515 sensitive_data.server_key = tmp;
518 for (i = 0; i < options.num_host_key_files; i++) {
519 if (sensitive_data.host_keys[i]) {
520 tmp = key_demote(sensitive_data.host_keys[i]);
521 key_free(sensitive_data.host_keys[i]);
522 sensitive_data.host_keys[i] = tmp;
523 if (tmp->type == KEY_RSA1)
524 sensitive_data.ssh1_host_key = tmp;
528 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
532 privsep_preauth_child(void)
539 /* Enable challenge-response authentication for privilege separation */
540 privsep_challenge_enable();
542 for (i = 0; i < 256; i++)
543 rnd[i] = arc4random();
544 RAND_seed(rnd, sizeof(rnd));
546 /* Demote the private keys to public keys. */
547 demote_sensitive_data();
549 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
550 fatal("Privilege separation user %s does not exist",
552 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
555 /* Change our root directory */
556 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
557 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
559 if (chdir("/") == -1)
560 fatal("chdir(\"/\"): %s", strerror(errno));
562 /* Drop our privileges */
563 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
566 /* XXX not ready, to heavy after chroot */
567 do_setusercontext(pw);
569 gidset[0] = pw->pw_gid;
570 if (setgroups(1, gidset) < 0)
571 fatal("setgroups: %.100s", strerror(errno));
572 permanently_set_uid(pw);
577 privsep_preauth(void)
579 Authctxt *authctxt = NULL;
583 /* Set up unprivileged child process to deal with network data */
584 pmonitor = monitor_init();
585 /* Store a pointer to the kex for later rekeying */
586 pmonitor->m_pkex = &xxx_kex;
590 fatal("fork of unprivileged child failed");
591 } else if (pid != 0) {
592 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
594 debug2("Network child is on pid %ld", (long)pid);
596 close(pmonitor->m_recvfd);
597 authctxt = monitor_child_preauth(pmonitor);
598 close(pmonitor->m_sendfd);
601 monitor_sync(pmonitor);
603 /* Wait for the child's exit status */
604 while (waitpid(pid, &status, 0) < 0)
608 /* Reinstall, since the child has finished */
609 fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
615 close(pmonitor->m_sendfd);
617 /* Demote the child */
618 if (getuid() == 0 || geteuid() == 0)
619 privsep_preauth_child();
620 setproctitle("%s", "[net]");
626 privsep_postauth(Authctxt *authctxt)
628 extern Authctxt *x_authctxt;
630 /* XXX - Remote port forwarding */
631 x_authctxt = authctxt;
633 #ifdef DISABLE_FD_PASSING
636 if (authctxt->pw->pw_uid == 0 || options.use_login) {
638 /* File descriptor passing is broken or root login */
639 monitor_apply_keystate(pmonitor);
644 /* Authentication complete */
646 if (startup_pipe != -1) {
651 /* New socket pair */
652 monitor_reinit(pmonitor);
654 pmonitor->m_pid = fork();
655 if (pmonitor->m_pid == -1)
656 fatal("fork of unprivileged child failed");
657 else if (pmonitor->m_pid != 0) {
658 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
660 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
661 close(pmonitor->m_recvfd);
662 monitor_child_postauth(pmonitor);
668 close(pmonitor->m_sendfd);
670 /* Demote the private keys to public keys. */
671 demote_sensitive_data();
673 /* Drop privileges */
674 do_setusercontext(authctxt->pw);
676 /* It is safe now to apply the key state */
677 monitor_apply_keystate(pmonitor);
681 list_hostkey_types(void)
688 for (i = 0; i < options.num_host_key_files; i++) {
689 Key *key = sensitive_data.host_keys[i];
695 if (buffer_len(&b) > 0)
696 buffer_append(&b, ",", 1);
697 p = key_ssh_name(key);
698 buffer_append(&b, p, strlen(p));
702 buffer_append(&b, "\0", 1);
703 p = xstrdup(buffer_ptr(&b));
705 debug("list_hostkey_types: %s", p);
710 get_hostkey_by_type(int type)
714 for (i = 0; i < options.num_host_key_files; i++) {
715 Key *key = sensitive_data.host_keys[i];
716 if (key != NULL && key->type == type)
723 get_hostkey_by_index(int ind)
725 if (ind < 0 || ind >= options.num_host_key_files)
727 return (sensitive_data.host_keys[ind]);
731 get_hostkey_index(Key *key)
735 for (i = 0; i < options.num_host_key_files; i++) {
736 if (key == sensitive_data.host_keys[i])
743 * returns 1 if connection should be dropped, 0 otherwise.
744 * dropping starts at connection #max_startups_begin with a probability
745 * of (max_startups_rate/100). the probability increases linearly until
746 * all connections are dropped for startups > max_startups
749 drop_connection(int startups)
753 if (startups < options.max_startups_begin)
755 if (startups >= options.max_startups)
757 if (options.max_startups_rate == 100)
760 p = 100 - options.max_startups_rate;
761 p *= startups - options.max_startups_begin;
762 p /= (double) (options.max_startups - options.max_startups_begin);
763 p += options.max_startups_rate;
765 r = arc4random() / (double) UINT_MAX;
767 debug("drop_connection: p %g, r %g", p, r);
768 return (r < p) ? 1 : 0;
774 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
775 fprintf(stderr, "Usage: %s [options]\n", __progname);
776 fprintf(stderr, "Options:\n");
777 fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
778 fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
779 fprintf(stderr, " -i Started from inetd\n");
780 fprintf(stderr, " -D Do not fork into daemon mode\n");
781 fprintf(stderr, " -t Only test configuration file and keys\n");
782 fprintf(stderr, " -q Quiet (no logging)\n");
783 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
784 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
785 fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
786 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
787 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
788 _PATH_HOST_KEY_FILE);
789 fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
790 fprintf(stderr, " -4 Use IPv4 only\n");
791 fprintf(stderr, " -6 Use IPv6 only\n");
792 fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n");
797 * Main program for the daemon.
800 main(int ac, char **av)
804 int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
808 struct sockaddr_storage from;
809 const char *remote_ip;
813 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
814 int listen_sock, maxfd;
819 int ret, key_used = 0;
821 #ifdef HAVE_SECUREWARE
822 (void)set_auth_parameters(ac, av);
824 __progname = get_progname(av[0]);
827 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
829 saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1));
830 for (i = 0; i < ac; i++)
831 saved_argv[i] = xstrdup(av[i]);
832 saved_argv[i] = NULL;
834 #ifndef HAVE_SETPROCTITLE
835 /* Prepare for later setproctitle emulation */
836 compat_init_setproctitle(ac, av);
840 /* Initialize configuration options to their default values. */
841 initialize_server_options(&options);
843 /* Parse command-line arguments. */
844 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:o:dDeiqtQ46")) != -1) {
853 config_file_name = optarg;
856 if (0 == debug_flag) {
858 options.log_level = SYSLOG_LEVEL_DEBUG1;
859 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
862 fprintf(stderr, "Too high debugging level.\n");
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;
916 client_version_string = optarg;
917 /* only makes sense with inetd_flag, i.e. no listen() */
924 utmp_len = atoi(optarg);
925 if (utmp_len > MAXHOSTNAMELEN) {
926 fprintf(stderr, "Invalid utmp length.\n");
931 if (process_server_config_line(&options, optarg,
932 "command-line", 0) != 0)
941 SSLeay_add_all_algorithms();
942 channel_set_af(IPv4or6);
945 * Force logging to stderr until we have loaded the private host
946 * key (unless started from inetd)
949 options.log_level == SYSLOG_LEVEL_NOT_SET ?
950 SYSLOG_LEVEL_INFO : options.log_level,
951 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
952 SYSLOG_FACILITY_AUTH : options.log_facility,
953 log_stderr || !inetd_flag);
956 /* Cray can define user privs drop all prives now!
957 * Not needed on PRIV_SU systems!
964 /* Read server configuration options from the configuration file. */
965 read_server_config(&options, config_file_name);
967 /* Fill in default values for those options not explicitly set. */
968 fill_default_server_options(&options);
970 /* Check that there are no remaining arguments. */
972 fprintf(stderr, "Extra argument %s.\n", av[optind]);
976 debug("sshd version %.100s", SSH_VERSION);
978 /* load private host keys */
979 sensitive_data.host_keys = xmalloc(options.num_host_key_files *
981 for (i = 0; i < options.num_host_key_files; i++)
982 sensitive_data.host_keys[i] = NULL;
983 sensitive_data.server_key = NULL;
984 sensitive_data.ssh1_host_key = NULL;
985 sensitive_data.have_ssh1_key = 0;
986 sensitive_data.have_ssh2_key = 0;
988 for (i = 0; i < options.num_host_key_files; i++) {
989 key = key_load_private(options.host_key_files[i], "", NULL);
990 sensitive_data.host_keys[i] = key;
992 error("Could not load host key: %s",
993 options.host_key_files[i]);
994 sensitive_data.host_keys[i] = NULL;
999 sensitive_data.ssh1_host_key = key;
1000 sensitive_data.have_ssh1_key = 1;
1004 sensitive_data.have_ssh2_key = 1;
1007 debug("private host key: #%d type %d %s", i, key->type,
1010 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
1011 logit("Disabling protocol version 1. Could not load host key");
1012 options.protocol &= ~SSH_PROTO_1;
1014 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1015 logit("Disabling protocol version 2. Could not load host key");
1016 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. */
1121 /* ignore SIGPIPE */
1122 signal(SIGPIPE, SIG_IGN);
1124 /* Start listening for a socket, unless started from inetd. */
1127 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
1133 * We intentionally do not close the descriptors 0, 1, and 2
1134 * as our code for setting the descriptors won\'t work if
1135 * ttyfd happens to be one of those.
1137 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
1138 if (options.protocol & SSH_PROTO_1)
1139 generate_ephemeral_server_key();
1141 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1142 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1144 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1145 fatal("Too many listen sockets. "
1146 "Enlarge MAX_LISTEN_SOCKS");
1147 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
1148 ntop, sizeof(ntop), strport, sizeof(strport),
1149 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1150 error("getnameinfo failed");
1153 /* Create socket for listening. */
1154 listen_sock = socket(ai->ai_family, ai->ai_socktype,
1156 if (listen_sock < 0) {
1157 /* kernel may not support ipv6 */
1158 verbose("socket: %.100s", strerror(errno));
1161 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
1162 error("listen_sock O_NONBLOCK: %s", strerror(errno));
1167 * Set socket options.
1168 * Allow local port reuse in TIME_WAIT.
1170 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1171 &on, sizeof(on)) == -1)
1172 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1174 debug("Bind to port %s on %s.", strport, ntop);
1176 /* Bind the socket to the desired port. */
1177 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1179 error("Bind to port %s on %s failed: %.200s.",
1180 strport, ntop, strerror(errno));
1184 listen_socks[num_listen_socks] = listen_sock;
1187 /* Start listening on the port. */
1188 logit("Server listening on %s port %s.", ntop, strport);
1189 if (listen(listen_sock, 5) < 0)
1190 fatal("listen: %.100s", strerror(errno));
1193 freeaddrinfo(options.listen_addrs);
1195 if (!num_listen_socks)
1196 fatal("Cannot bind any address.");
1198 if (options.protocol & SSH_PROTO_1)
1199 generate_ephemeral_server_key();
1202 * Arrange to restart on SIGHUP. The handler needs
1205 signal(SIGHUP, sighup_handler);
1207 signal(SIGTERM, sigterm_handler);
1208 signal(SIGQUIT, sigterm_handler);
1210 /* Arrange SIGCHLD to be caught. */
1211 signal(SIGCHLD, main_sigchld_handler);
1213 /* Write out the pid file after the sigterm handler is setup */
1216 * Record our pid in /var/run/sshd.pid to make it
1217 * easier to kill the correct sshd. We don't want to
1218 * do this before the bind above because the bind will
1219 * fail if there already is a daemon, and this will
1220 * overwrite any old pid in the file.
1222 f = fopen(options.pid_file, "wb");
1224 error("Couldn't create pid file \"%s\": %s",
1225 options.pid_file, strerror(errno));
1227 fprintf(f, "%ld\n", (long) getpid());
1232 /* setup fd set for listen */
1235 for (i = 0; i < num_listen_socks; i++)
1236 if (listen_socks[i] > maxfd)
1237 maxfd = listen_socks[i];
1238 /* pipes connected to unauthenticated childs */
1239 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1240 for (i = 0; i < options.max_startups; i++)
1241 startup_pipes[i] = -1;
1244 * Stay listening for connections until the system crashes or
1245 * the daemon is killed with a signal.
1248 if (received_sighup)
1252 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
1253 fdset = (fd_set *)xmalloc(fdsetsz);
1254 memset(fdset, 0, fdsetsz);
1256 for (i = 0; i < num_listen_socks; i++)
1257 FD_SET(listen_socks[i], fdset);
1258 for (i = 0; i < options.max_startups; i++)
1259 if (startup_pipes[i] != -1)
1260 FD_SET(startup_pipes[i], fdset);
1262 /* Wait in select until there is a connection. */
1263 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1264 if (ret < 0 && errno != EINTR)
1265 error("select: %.100s", strerror(errno));
1266 if (received_sigterm) {
1267 logit("Received signal %d; terminating.",
1268 (int) received_sigterm);
1269 close_listen_socks();
1270 unlink(options.pid_file);
1273 if (key_used && key_do_regen) {
1274 generate_ephemeral_server_key();
1281 for (i = 0; i < options.max_startups; i++)
1282 if (startup_pipes[i] != -1 &&
1283 FD_ISSET(startup_pipes[i], fdset)) {
1285 * the read end of the pipe is ready
1286 * if the child has closed the pipe
1287 * after successful authentication
1288 * or if the child has died
1290 close(startup_pipes[i]);
1291 startup_pipes[i] = -1;
1294 for (i = 0; i < num_listen_socks; i++) {
1295 if (!FD_ISSET(listen_socks[i], fdset))
1297 fromlen = sizeof(from);
1298 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1301 if (errno != EINTR && errno != EWOULDBLOCK)
1302 error("accept: %.100s", strerror(errno));
1305 if (fcntl(newsock, F_SETFL, 0) < 0) {
1306 error("newsock del O_NONBLOCK: %s", strerror(errno));
1310 if (drop_connection(startups) == 1) {
1311 debug("drop connection #%d", startups);
1315 if (pipe(startup_p) == -1) {
1320 for (j = 0; j < options.max_startups; j++)
1321 if (startup_pipes[j] == -1) {
1322 startup_pipes[j] = startup_p[0];
1323 if (maxfd < startup_p[0])
1324 maxfd = startup_p[0];
1330 * Got connection. Fork a child to handle it, unless
1331 * we are in debugging mode.
1335 * In debugging mode. Close the listening
1336 * socket, and start processing the
1337 * connection without forking.
1339 debug("Server will not fork when running in debugging mode.");
1340 close_listen_socks();
1348 * Normal production daemon. Fork, and have
1349 * the child process the connection. The
1350 * parent continues listening.
1352 if ((pid = fork()) == 0) {
1354 * Child. Close the listening and max_startup
1355 * sockets. Start using the accepted socket.
1356 * Reinitialize logging (since our pid has
1357 * changed). We break out of the loop to handle
1360 startup_pipe = startup_p[1];
1361 close_startup_pipes();
1362 close_listen_socks();
1365 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1370 /* Parent. Stay in the loop. */
1372 error("fork: %.100s", strerror(errno));
1374 debug("Forked child %ld.", (long)pid);
1376 close(startup_p[1]);
1378 /* Mark that the key has been used (it was "given" to the child). */
1379 if ((options.protocol & SSH_PROTO_1) &&
1381 /* Schedule server key regeneration alarm. */
1382 mysignal(SIGALRM, key_regeneration_alarm);
1383 alarm(options.key_regeneration_time);
1389 /* Close the new socket (the child is now taking care of it). */
1392 /* child process check (or debug mode) */
1393 if (num_listen_socks < 0)
1398 /* This is the child processing a new connection. */
1401 * Create a new session and process group since the 4.4BSD
1402 * setlogin() affects the entire process group. We don't
1403 * want the child to be able to affect the parent.
1405 #if !defined(SSHD_ACQUIRES_CTTY)
1407 * If setsid is called, on some platforms sshd will later acquire a
1408 * controlling terminal which will result in "could not set
1409 * controlling tty" errors.
1411 if (!debug_flag && !inetd_flag && setsid() < 0)
1412 error("setsid: %.100s", strerror(errno));
1416 * Disable the key regeneration alarm. We will not regenerate the
1417 * key since we are no longer in a position to give it to anyone. We
1418 * will not restart on SIGHUP since it no longer makes sense.
1421 signal(SIGALRM, SIG_DFL);
1422 signal(SIGHUP, SIG_DFL);
1423 signal(SIGTERM, SIG_DFL);
1424 signal(SIGQUIT, SIG_DFL);
1425 signal(SIGCHLD, SIG_DFL);
1426 signal(SIGINT, SIG_DFL);
1428 /* Set keepalives if requested. */
1429 if (options.keepalives &&
1430 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
1432 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1435 * Register our connection. This turns encryption off because we do
1438 packet_set_connection(sock_in, sock_out);
1440 remote_port = get_remote_port();
1441 remote_ip = get_remote_ipaddr();
1444 /* Check whether logins are denied from this host. */
1446 struct request_info req;
1448 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
1451 if (!hosts_access(&req)) {
1452 debug("Connection refused by tcp wrapper");
1455 fatal("libwrap refuse returns");
1458 #endif /* LIBWRAP */
1460 /* Log the connection. */
1461 verbose("Connection from %.500s port %d", remote_ip, remote_port);
1464 * We don\'t want to listen forever unless the other side
1465 * successfully authenticates itself. So we set up an alarm which is
1466 * cleared after successful authentication. A limit of zero
1467 * indicates no limit. Note that we don\'t set the alarm in debugging
1468 * mode; it is just annoying to have the server exit just when you
1469 * are about to discover the bug.
1471 mysignal(SIGALRM, grace_alarm_handler);
1473 alarm(options.login_grace_time);
1475 sshd_exchange_identification(sock_in, sock_out);
1477 * Check that the connection comes from a privileged port.
1478 * Rhosts-Authentication only makes sense from privileged
1479 * programs. Of course, if the intruder has root access on his local
1480 * machine, he can connect from any port. So do not use these
1481 * authentication methods from machines that you do not trust.
1483 if (options.rhosts_authentication &&
1484 (remote_port >= IPPORT_RESERVED ||
1485 remote_port < IPPORT_RESERVED / 2)) {
1486 debug("Rhosts Authentication disabled, "
1487 "originating port %d not trusted.", remote_port);
1488 options.rhosts_authentication = 0;
1490 #if defined(KRB4) && !defined(KRB5)
1491 if (!packet_connection_is_ipv4() &&
1492 options.kerberos_authentication) {
1493 debug("Kerberos Authentication disabled, only available for IPv4.");
1494 options.kerberos_authentication = 0;
1496 #endif /* KRB4 && !KRB5 */
1498 /* If machine has AFS, set process authentication group. */
1505 packet_set_nonblocking();
1507 /* prepare buffers to collect authentication messages */
1508 buffer_init(&loginmsg);
1511 if ((authctxt = privsep_preauth()) != NULL)
1514 /* perform the key exchange */
1515 /* authenticate user and start session */
1518 authctxt = do_authentication2();
1521 authctxt = do_authentication();
1524 * If we use privilege separation, the unprivileged child transfers
1525 * the current keystate and exits
1528 mm_send_keystate(pmonitor);
1534 * In privilege separation, we fork another child and prepare
1535 * file descriptor passing.
1538 privsep_postauth(authctxt);
1539 /* the monitor process [priv] will not return */
1541 destroy_sensitive_data();
1544 /* Perform session preparation. */
1545 do_authenticated(authctxt);
1547 /* The connection has been terminated. */
1548 verbose("Closing connection to %.100s", remote_ip);
1551 if (options.use_pam)
1553 #endif /* USE_PAM */
1564 * Decrypt session_key_int using our private server key and private host key
1565 * (key with larger modulus first).
1568 ssh1_session_key(BIGNUM *session_key_int)
1572 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1573 /* Server key has bigger modulus. */
1574 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1575 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1576 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1577 get_remote_ipaddr(),
1578 BN_num_bits(sensitive_data.server_key->rsa->n),
1579 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1580 SSH_KEY_BITS_RESERVED);
1582 if (rsa_private_decrypt(session_key_int, session_key_int,
1583 sensitive_data.server_key->rsa) <= 0)
1585 if (rsa_private_decrypt(session_key_int, session_key_int,
1586 sensitive_data.ssh1_host_key->rsa) <= 0)
1589 /* Host key has bigger modulus (or they are equal). */
1590 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1591 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1592 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1593 get_remote_ipaddr(),
1594 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1595 BN_num_bits(sensitive_data.server_key->rsa->n),
1596 SSH_KEY_BITS_RESERVED);
1598 if (rsa_private_decrypt(session_key_int, session_key_int,
1599 sensitive_data.ssh1_host_key->rsa) < 0)
1601 if (rsa_private_decrypt(session_key_int, session_key_int,
1602 sensitive_data.server_key->rsa) < 0)
1615 BIGNUM *session_key_int;
1616 u_char session_key[SSH_SESSION_KEY_LENGTH];
1618 u_int cipher_type, auth_mask, protocol_flags;
1622 * Generate check bytes that the client must send back in the user
1623 * packet in order for it to be accepted; this is used to defy ip
1624 * spoofing attacks. Note that this only works against somebody
1625 * doing IP spoofing from a remote machine; any machine on the local
1626 * network can still see outgoing packets and catch the random
1627 * cookie. This only affects rhosts authentication, and this is one
1628 * of the reasons why it is inherently insecure.
1630 for (i = 0; i < 8; i++) {
1633 cookie[i] = rnd & 0xff;
1638 * Send our public key. We include in the packet 64 bits of random
1639 * data that must be matched in the reply in order to prevent IP
1642 packet_start(SSH_SMSG_PUBLIC_KEY);
1643 for (i = 0; i < 8; i++)
1644 packet_put_char(cookie[i]);
1646 /* Store our public server RSA key. */
1647 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1648 packet_put_bignum(sensitive_data.server_key->rsa->e);
1649 packet_put_bignum(sensitive_data.server_key->rsa->n);
1651 /* Store our public host RSA key. */
1652 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1653 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1654 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
1656 /* Put protocol flags. */
1657 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1659 /* Declare which ciphers we support. */
1660 packet_put_int(cipher_mask_ssh1(0));
1662 /* Declare supported authentication types. */
1664 if (options.rhosts_authentication)
1665 auth_mask |= 1 << SSH_AUTH_RHOSTS;
1666 if (options.rhosts_rsa_authentication)
1667 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1668 if (options.rsa_authentication)
1669 auth_mask |= 1 << SSH_AUTH_RSA;
1670 #if defined(KRB4) || defined(KRB5)
1671 if (options.kerberos_authentication)
1672 auth_mask |= 1 << SSH_AUTH_KERBEROS;
1674 #if defined(AFS) || defined(KRB5)
1675 if (options.kerberos_tgt_passing)
1676 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
1679 if (options.afs_token_passing)
1680 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
1682 if (options.challenge_response_authentication == 1)
1683 auth_mask |= 1 << SSH_AUTH_TIS;
1684 if (options.password_authentication)
1685 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1686 packet_put_int(auth_mask);
1688 /* Send the packet and wait for it to be sent. */
1690 packet_write_wait();
1692 debug("Sent %d bit server key and %d bit host key.",
1693 BN_num_bits(sensitive_data.server_key->rsa->n),
1694 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1696 /* Read clients reply (cipher type and session key). */
1697 packet_read_expect(SSH_CMSG_SESSION_KEY);
1699 /* Get cipher type and check whether we accept this. */
1700 cipher_type = packet_get_char();
1702 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1703 packet_disconnect("Warning: client selects unsupported cipher.");
1705 /* Get check bytes from the packet. These must match those we
1706 sent earlier with the public key packet. */
1707 for (i = 0; i < 8; i++)
1708 if (cookie[i] != packet_get_char())
1709 packet_disconnect("IP Spoofing check bytes do not match.");
1711 debug("Encryption type: %.200s", cipher_name(cipher_type));
1713 /* Get the encrypted integer. */
1714 if ((session_key_int = BN_new()) == NULL)
1715 fatal("do_ssh1_kex: BN_new failed");
1716 packet_get_bignum(session_key_int);
1718 protocol_flags = packet_get_int();
1719 packet_set_protocol_flags(protocol_flags);
1722 /* Decrypt session_key_int using host/server keys */
1723 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1726 * Extract session key from the decrypted integer. The key is in the
1727 * least significant 256 bits of the integer; the first byte of the
1728 * key is in the highest bits.
1731 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1732 len = BN_num_bytes(session_key_int);
1733 if (len < 0 || len > sizeof(session_key)) {
1734 error("do_connection: bad session key len from %s: "
1735 "session_key_int %d > sizeof(session_key) %lu",
1736 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
1739 memset(session_key, 0, sizeof(session_key));
1740 BN_bn2bin(session_key_int,
1741 session_key + sizeof(session_key) - len);
1743 compute_session_id(session_id, cookie,
1744 sensitive_data.ssh1_host_key->rsa->n,
1745 sensitive_data.server_key->rsa->n);
1747 * Xor the first 16 bytes of the session key with the
1750 for (i = 0; i < 16; i++)
1751 session_key[i] ^= session_id[i];
1755 int bytes = BN_num_bytes(session_key_int);
1756 u_char *buf = xmalloc(bytes);
1759 logit("do_connection: generating a fake encryption key");
1760 BN_bn2bin(session_key_int, buf);
1762 MD5_Update(&md, buf, bytes);
1763 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1764 MD5_Final(session_key, &md);
1766 MD5_Update(&md, session_key, 16);
1767 MD5_Update(&md, buf, bytes);
1768 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1769 MD5_Final(session_key + 16, &md);
1770 memset(buf, 0, bytes);
1772 for (i = 0; i < 16; i++)
1773 session_id[i] = session_key[i] ^ session_key[i + 16];
1775 /* Destroy the private and public keys. No longer. */
1776 destroy_sensitive_data();
1779 mm_ssh1_session_id(session_id);
1781 /* Destroy the decrypted integer. It is no longer needed. */
1782 BN_clear_free(session_key_int);
1784 /* Set the session key. From this on all communications will be encrypted. */
1785 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1787 /* Destroy our copy of the session key. It is no longer needed. */
1788 memset(session_key, 0, sizeof(session_key));
1790 debug("Received session key; encryption turned on.");
1792 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
1793 packet_start(SSH_SMSG_SUCCESS);
1795 packet_write_wait();
1799 * SSH2 key exchange: diffie-hellman-group1-sha1
1806 if (options.ciphers != NULL) {
1807 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1808 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1810 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1811 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
1812 myproposal[PROPOSAL_ENC_ALGS_STOC] =
1813 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1815 if (options.macs != NULL) {
1816 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1817 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1819 if (!options.compression) {
1820 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1821 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1823 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1825 /* start key exchange */
1826 kex = kex_setup(myproposal);
1827 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1828 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1830 kex->client_version_string=client_version_string;
1831 kex->server_version_string=server_version_string;
1832 kex->load_host_key=&get_hostkey_by_type;
1833 kex->host_key_index=&get_hostkey_index;
1837 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1839 session_id2 = kex->session_id;
1840 session_id2_len = kex->session_id_len;
1843 /* send 1st encrypted/maced/compressed message */
1844 packet_start(SSH2_MSG_IGNORE);
1845 packet_put_cstring("markus");
1847 packet_write_wait();