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 1.263 2003/02/16 17:09:57 markus Exp $");
47 #include <openssl/dh.h>
48 #include <openssl/bn.h>
49 #include <openssl/md5.h>
50 #include <openssl/rand.h>
51 #ifdef HAVE_SECUREWARE
52 #include <sys/security.h>
73 #include "myproposal.h"
75 #include "pathnames.h"
83 #include "monitor_mm.h"
85 #include "monitor_wrap.h"
86 #include "monitor_fdpass.h"
93 #include <openssl/md5.h>
100 int allow_severity = LOG_INFO;
101 int deny_severity = LOG_WARNING;
108 #ifdef HAVE___PROGNAME
109 extern char *__progname;
114 /* Server configuration options. */
115 ServerOptions options;
117 /* Name of the server configuration file. */
118 char *config_file_name;
121 * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
122 * Default value is AF_UNSPEC means both IPv4 and IPv6.
125 int IPv4or6 = AF_INET;
127 int IPv4or6 = AF_UNSPEC;
131 * Debug mode flag. This can be set on the command line. If debug
132 * mode is enabled, extra debugging output will be sent to the system
133 * log, the daemon will not go to background, and will exit after processing
134 * the first connection.
138 /* Flag indicating that the daemon should only test the configuration and keys. */
141 /* Flag indicating that the daemon is being started from inetd. */
144 /* Flag indicating that sshd should not detach and become a daemon. */
145 int no_daemon_flag = 0;
147 /* debug goes to stderr unless inetd_flag is set */
150 /* Saved arguments to main(). */
155 * The sockets that the server is listening; this is used in the SIGHUP
158 #define MAX_LISTEN_SOCKS 16
159 int listen_socks[MAX_LISTEN_SOCKS];
160 int num_listen_socks = 0;
163 * the client's version string, passed by sshd2 in compat mode. if != NULL,
164 * sshd will skip the version-number exchange
166 char *client_version_string = NULL;
167 char *server_version_string = NULL;
169 /* for rekeying XXX fixme */
173 * Any really sensitive data in the application is contained in this
174 * structure. The idea is that this structure could be locked into memory so
175 * that the pages do not get written into swap. However, there are some
176 * problems. The private key contains BIGNUMs, and we do not (in principle)
177 * have access to the internals of them, and locking just the structure is
178 * not very useful. Currently, memory locking is not implemented.
181 Key *server_key; /* ephemeral server key */
182 Key *ssh1_host_key; /* ssh1 host key */
183 Key **host_keys; /* all private host keys */
186 u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH];
190 * Flag indicating whether the RSA server key needs to be regenerated.
191 * Is set in the SIGALRM handler and cleared when the key is regenerated.
193 static volatile sig_atomic_t key_do_regen = 0;
195 /* This is set to true when a signal is received. */
196 static volatile sig_atomic_t received_sighup = 0;
197 static volatile sig_atomic_t received_sigterm = 0;
199 /* session identifier, used by RSA-auth */
200 u_char session_id[16];
203 u_char *session_id2 = NULL;
204 int session_id2_len = 0;
206 /* record remote hostname or ip */
207 u_int utmp_len = MAXHOSTNAMELEN;
209 /* options.max_startup sized array of fd ints */
210 int *startup_pipes = NULL;
211 int startup_pipe; /* in child */
213 /* variables used for privilege separation */
215 struct monitor *pmonitor;
217 /* Prototypes for various functions defined later in this file. */
218 void destroy_sensitive_data(void);
219 void demote_sensitive_data(void);
221 static void do_ssh1_kex(void);
222 static void do_ssh2_kex(void);
225 * Close all listening sockets
228 close_listen_socks(void)
232 for (i = 0; i < num_listen_socks; i++)
233 close(listen_socks[i]);
234 num_listen_socks = -1;
238 close_startup_pipes(void)
243 for (i = 0; i < options.max_startups; i++)
244 if (startup_pipes[i] != -1)
245 close(startup_pipes[i]);
249 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
250 * the effect is to reread the configuration file (and to regenerate
254 sighup_handler(int sig)
256 int save_errno = errno;
259 signal(SIGHUP, sighup_handler);
264 * Called from the main program after receiving SIGHUP.
265 * Restarts the server.
270 log("Received SIGHUP; restarting.");
271 close_listen_socks();
272 close_startup_pipes();
273 execv(saved_argv[0], saved_argv);
274 log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
280 * Generic signal handler for terminating signals in the master daemon.
283 sigterm_handler(int sig)
285 received_sigterm = sig;
289 * SIGCHLD handler. This is called whenever a child dies. This will then
290 * reap any zombies left by exited children.
293 main_sigchld_handler(int sig)
295 int save_errno = errno;
299 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
300 (pid < 0 && errno == EINTR))
303 signal(SIGCHLD, main_sigchld_handler);
308 * Signal handler for the alarm after the login grace period has expired.
311 grace_alarm_handler(int sig)
313 /* XXX no idea how fix this signal handler */
315 /* Log error and exit. */
316 fatal("Timeout before authentication for %s", get_remote_ipaddr());
320 * Signal handler for the key regeneration alarm. Note that this
321 * alarm only occurs in the daemon waiting for connections, and it does not
322 * do anything with the private key or random state before forking.
323 * Thus there should be no concurrency control/asynchronous execution
327 generate_ephemeral_server_key(void)
332 verbose("Generating %s%d bit RSA key.",
333 sensitive_data.server_key ? "new " : "", options.server_key_bits);
334 if (sensitive_data.server_key != NULL)
335 key_free(sensitive_data.server_key);
336 sensitive_data.server_key = key_generate(KEY_RSA1,
337 options.server_key_bits);
338 verbose("RSA key generation complete.");
340 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
343 sensitive_data.ssh1_cookie[i] = rnd & 0xff;
350 key_regeneration_alarm(int sig)
352 int save_errno = errno;
354 signal(SIGALRM, SIG_DFL);
360 sshd_exchange_identification(int sock_in, int sock_out)
363 int remote_major, remote_minor;
366 char buf[256]; /* Must not be larger than remote_version. */
367 char remote_version[256]; /* Must be at least as big as buf. */
369 if ((options.protocol & SSH_PROTO_1) &&
370 (options.protocol & SSH_PROTO_2)) {
371 major = PROTOCOL_MAJOR_1;
373 } else if (options.protocol & SSH_PROTO_2) {
374 major = PROTOCOL_MAJOR_2;
375 minor = PROTOCOL_MINOR_2;
377 major = PROTOCOL_MAJOR_1;
378 minor = PROTOCOL_MINOR_1;
380 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
381 server_version_string = xstrdup(buf);
383 if (client_version_string == NULL) {
384 /* Send our protocol version identification. */
385 if (atomicio(write, sock_out, server_version_string,
386 strlen(server_version_string))
387 != strlen(server_version_string)) {
388 log("Could not write ident string to %s", get_remote_ipaddr());
392 /* Read other sides version identification. */
393 memset(buf, 0, sizeof(buf));
394 for (i = 0; i < sizeof(buf) - 1; i++) {
395 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
396 log("Did not receive identification string from %s",
397 get_remote_ipaddr());
400 if (buf[i] == '\r') {
402 /* Kludge for F-Secure Macintosh < 1.0.2 */
404 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
408 if (buf[i] == '\n') {
413 buf[sizeof(buf) - 1] = 0;
414 client_version_string = xstrdup(buf);
418 * Check that the versions match. In future this might accept
419 * several versions and set appropriate flags to handle them.
421 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
422 &remote_major, &remote_minor, remote_version) != 3) {
423 s = "Protocol mismatch.\n";
424 (void) atomicio(write, sock_out, s, strlen(s));
427 log("Bad protocol version identification '%.100s' from %s",
428 client_version_string, get_remote_ipaddr());
431 debug("Client protocol version %d.%d; client software version %.100s",
432 remote_major, remote_minor, remote_version);
434 compat_datafellows(remote_version);
436 if (datafellows & SSH_BUG_PROBE) {
437 log("probed from %s with %s. Don't panic.",
438 get_remote_ipaddr(), client_version_string);
442 if (datafellows & SSH_BUG_SCANNER) {
443 log("scanned from %s with %s. Don't panic.",
444 get_remote_ipaddr(), client_version_string);
449 switch (remote_major) {
451 if (remote_minor == 99) {
452 if (options.protocol & SSH_PROTO_2)
458 if (!(options.protocol & SSH_PROTO_1)) {
462 if (remote_minor < 3) {
463 packet_disconnect("Your ssh version is too old and "
464 "is no longer supported. Please install a newer version.");
465 } else if (remote_minor == 3) {
466 /* note that this disables agent-forwarding */
471 if (options.protocol & SSH_PROTO_2) {
480 chop(server_version_string);
481 debug("Local version string %.200s", server_version_string);
484 s = "Protocol major versions differ.\n";
485 (void) atomicio(write, sock_out, s, strlen(s));
488 log("Protocol major versions differ for %s: %.200s vs. %.200s",
490 server_version_string, client_version_string);
495 /* Destroy the host and server keys. They will no longer be needed. */
497 destroy_sensitive_data(void)
501 if (sensitive_data.server_key) {
502 key_free(sensitive_data.server_key);
503 sensitive_data.server_key = NULL;
505 for (i = 0; i < options.num_host_key_files; i++) {
506 if (sensitive_data.host_keys[i]) {
507 key_free(sensitive_data.host_keys[i]);
508 sensitive_data.host_keys[i] = NULL;
511 sensitive_data.ssh1_host_key = NULL;
512 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
515 /* Demote private to public keys for network child */
517 demote_sensitive_data(void)
522 if (sensitive_data.server_key) {
523 tmp = key_demote(sensitive_data.server_key);
524 key_free(sensitive_data.server_key);
525 sensitive_data.server_key = tmp;
528 for (i = 0; i < options.num_host_key_files; i++) {
529 if (sensitive_data.host_keys[i]) {
530 tmp = key_demote(sensitive_data.host_keys[i]);
531 key_free(sensitive_data.host_keys[i]);
532 sensitive_data.host_keys[i] = tmp;
533 if (tmp->type == KEY_RSA1)
534 sensitive_data.ssh1_host_key = tmp;
538 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
542 privsep_preauth_child(void)
549 /* Enable challenge-response authentication for privilege separation */
550 privsep_challenge_enable();
552 for (i = 0; i < 256; i++)
553 rnd[i] = arc4random();
554 RAND_seed(rnd, sizeof(rnd));
556 /* Demote the private keys to public keys. */
557 demote_sensitive_data();
559 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
560 fatal("Privilege separation user %s does not exist",
562 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
565 /* Change our root directory */
566 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
567 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
569 if (chdir("/") == -1)
570 fatal("chdir(\"/\"): %s", strerror(errno));
572 /* Drop our privileges */
573 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
576 /* XXX not ready, to heavy after chroot */
577 do_setusercontext(pw);
579 gidset[0] = pw->pw_gid;
580 if (setgid(pw->pw_gid) < 0)
581 fatal("setgid failed for %u", pw->pw_gid );
582 if (setgroups(1, gidset) < 0)
583 fatal("setgroups: %.100s", strerror(errno));
584 permanently_set_uid(pw);
589 privsep_preauth(void)
591 Authctxt *authctxt = NULL;
595 /* Set up unprivileged child process to deal with network data */
596 pmonitor = monitor_init();
597 /* Store a pointer to the kex for later rekeying */
598 pmonitor->m_pkex = &xxx_kex;
602 fatal("fork of unprivileged child failed");
603 } else if (pid != 0) {
604 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
606 debug2("Network child is on pid %ld", (long)pid);
608 close(pmonitor->m_recvfd);
609 authctxt = monitor_child_preauth(pmonitor);
610 close(pmonitor->m_sendfd);
613 monitor_sync(pmonitor);
615 /* Wait for the child's exit status */
616 while (waitpid(pid, &status, 0) < 0)
620 /* Reinstall, since the child has finished */
621 fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
627 close(pmonitor->m_sendfd);
629 /* Demote the child */
630 if (getuid() == 0 || geteuid() == 0)
631 privsep_preauth_child();
632 setproctitle("%s", "[net]");
638 privsep_postauth(Authctxt *authctxt)
640 extern Authctxt *x_authctxt;
642 /* XXX - Remote port forwarding */
643 x_authctxt = authctxt;
645 #ifdef DISABLE_FD_PASSING
648 if (authctxt->pw->pw_uid == 0 || options.use_login) {
650 /* File descriptor passing is broken or root login */
651 monitor_apply_keystate(pmonitor);
656 /* Authentication complete */
658 if (startup_pipe != -1) {
663 /* New socket pair */
664 monitor_reinit(pmonitor);
666 pmonitor->m_pid = fork();
667 if (pmonitor->m_pid == -1)
668 fatal("fork of unprivileged child failed");
669 else if (pmonitor->m_pid != 0) {
670 fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
672 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
673 close(pmonitor->m_recvfd);
674 monitor_child_postauth(pmonitor);
680 close(pmonitor->m_sendfd);
682 /* Demote the private keys to public keys. */
683 demote_sensitive_data();
685 /* Drop privileges */
686 do_setusercontext(authctxt->pw);
688 /* It is safe now to apply the key state */
689 monitor_apply_keystate(pmonitor);
693 list_hostkey_types(void)
700 for (i = 0; i < options.num_host_key_files; i++) {
701 Key *key = sensitive_data.host_keys[i];
707 if (buffer_len(&b) > 0)
708 buffer_append(&b, ",", 1);
709 p = key_ssh_name(key);
710 buffer_append(&b, p, strlen(p));
714 buffer_append(&b, "\0", 1);
715 p = xstrdup(buffer_ptr(&b));
717 debug("list_hostkey_types: %s", p);
722 get_hostkey_by_type(int type)
726 for (i = 0; i < options.num_host_key_files; i++) {
727 Key *key = sensitive_data.host_keys[i];
728 if (key != NULL && key->type == type)
735 get_hostkey_by_index(int ind)
737 if (ind < 0 || ind >= options.num_host_key_files)
739 return (sensitive_data.host_keys[ind]);
743 get_hostkey_index(Key *key)
747 for (i = 0; i < options.num_host_key_files; i++) {
748 if (key == sensitive_data.host_keys[i])
755 * returns 1 if connection should be dropped, 0 otherwise.
756 * dropping starts at connection #max_startups_begin with a probability
757 * of (max_startups_rate/100). the probability increases linearly until
758 * all connections are dropped for startups > max_startups
761 drop_connection(int startups)
765 if (startups < options.max_startups_begin)
767 if (startups >= options.max_startups)
769 if (options.max_startups_rate == 100)
772 p = 100 - options.max_startups_rate;
773 p *= startups - options.max_startups_begin;
774 p /= (double) (options.max_startups - options.max_startups_begin);
775 p += options.max_startups_rate;
777 r = arc4random() / (double) UINT_MAX;
779 debug("drop_connection: p %g, r %g", p, r);
780 return (r < p) ? 1 : 0;
786 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
787 fprintf(stderr, "Usage: %s [options]\n", __progname);
788 fprintf(stderr, "Options:\n");
789 fprintf(stderr, " -f file Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
790 fprintf(stderr, " -d Debugging mode (multiple -d means more debugging)\n");
791 fprintf(stderr, " -i Started from inetd\n");
792 fprintf(stderr, " -D Do not fork into daemon mode\n");
793 fprintf(stderr, " -t Only test configuration file and keys\n");
794 fprintf(stderr, " -q Quiet (no logging)\n");
795 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
796 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
797 fprintf(stderr, " -g seconds Grace period for authentication (default: 600)\n");
798 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
799 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
800 _PATH_HOST_KEY_FILE);
801 fprintf(stderr, " -u len Maximum hostname length for utmp recording\n");
802 fprintf(stderr, " -4 Use IPv4 only\n");
803 fprintf(stderr, " -6 Use IPv6 only\n");
804 fprintf(stderr, " -o option Process the option as if it was read from a configuration file.\n");
809 * Main program for the daemon.
812 main(int ac, char **av)
816 int opt, sock_in = 0, sock_out = 0, newsock, j, i, fdsetsz, on = 1;
820 struct sockaddr_storage from;
821 const char *remote_ip;
825 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
826 int listen_sock, maxfd;
831 int ret, key_used = 0;
833 #ifdef HAVE_SECUREWARE
834 (void)set_auth_parameters(ac, av);
836 __progname = get_progname(av[0]);
838 config_file_name = _PATH_SERVER_CONFIG_FILE;
841 /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
844 saved_argv = xmalloc(sizeof(*saved_argv) * ac);
845 for (i = 0; i < ac; i++)
846 saved_argv[i] = xstrdup(av[i]);
848 #ifndef HAVE_SETPROCTITLE
849 /* Prepare for later setproctitle emulation */
850 compat_init_setproctitle(ac, av);
853 /* Initialize configuration options to their default values. */
854 initialize_server_options(&options);
856 /* Parse command-line arguments. */
857 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:o:dDeiqtQ46")) != -1) {
866 config_file_name = optarg;
869 if (0 == debug_flag) {
871 options.log_level = SYSLOG_LEVEL_DEBUG1;
872 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
875 fprintf(stderr, "Too high debugging level.\n");
892 options.log_level = SYSLOG_LEVEL_QUIET;
895 options.server_key_bits = atoi(optarg);
898 options.ports_from_cmdline = 1;
899 if (options.num_ports >= MAX_PORTS) {
900 fprintf(stderr, "too many ports.\n");
903 options.ports[options.num_ports++] = a2port(optarg);
904 if (options.ports[options.num_ports-1] == 0) {
905 fprintf(stderr, "Bad port number.\n");
910 if ((options.login_grace_time = convtime(optarg)) == -1) {
911 fprintf(stderr, "Invalid login grace time.\n");
916 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
917 fprintf(stderr, "Invalid key regeneration interval.\n");
922 if (options.num_host_key_files >= MAX_HOSTKEYS) {
923 fprintf(stderr, "too many host keys.\n");
926 options.host_key_files[options.num_host_key_files++] = optarg;
929 client_version_string = optarg;
930 /* only makes sense with inetd_flag, i.e. no listen() */
937 utmp_len = atoi(optarg);
938 if (utmp_len > MAXHOSTNAMELEN) {
939 fprintf(stderr, "Invalid utmp length.\n");
944 if (process_server_config_line(&options, optarg,
945 "command-line", 0) != 0)
954 SSLeay_add_all_algorithms();
955 channel_set_af(IPv4or6);
958 * Force logging to stderr until we have loaded the private host
959 * key (unless started from inetd)
962 options.log_level == SYSLOG_LEVEL_NOT_SET ?
963 SYSLOG_LEVEL_INFO : options.log_level,
964 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
965 SYSLOG_FACILITY_AUTH : options.log_facility,
966 log_stderr || !inetd_flag);
969 /* Cray can define user privs drop all prives now!
970 * Not needed on PRIV_SU systems!
977 /* Read server configuration options from the configuration file. */
978 read_server_config(&options, config_file_name);
980 /* Fill in default values for those options not explicitly set. */
981 fill_default_server_options(&options);
983 /* Check that there are no remaining arguments. */
985 fprintf(stderr, "Extra argument %s.\n", av[optind]);
989 debug("sshd version %.100s", SSH_VERSION);
991 /* load private host keys */
992 sensitive_data.host_keys = xmalloc(options.num_host_key_files *
994 for (i = 0; i < options.num_host_key_files; i++)
995 sensitive_data.host_keys[i] = NULL;
996 sensitive_data.server_key = NULL;
997 sensitive_data.ssh1_host_key = NULL;
998 sensitive_data.have_ssh1_key = 0;
999 sensitive_data.have_ssh2_key = 0;
1001 for (i = 0; i < options.num_host_key_files; i++) {
1002 key = key_load_private(options.host_key_files[i], "", NULL);
1003 sensitive_data.host_keys[i] = key;
1005 error("Could not load host key: %s",
1006 options.host_key_files[i]);
1007 sensitive_data.host_keys[i] = NULL;
1010 switch (key->type) {
1012 sensitive_data.ssh1_host_key = key;
1013 sensitive_data.have_ssh1_key = 1;
1017 sensitive_data.have_ssh2_key = 1;
1020 debug("private host key: #%d type %d %s", i, key->type,
1023 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
1024 log("Disabling protocol version 1. Could not load host key");
1025 options.protocol &= ~SSH_PROTO_1;
1028 /* The GSSAPI key exchange can run without a host key */
1029 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1030 log("Disabling protocol version 2. Could not load host key");
1031 options.protocol &= ~SSH_PROTO_2;
1034 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1035 log("sshd: no hostkeys available -- exiting.");
1039 /* Check certain values for sanity. */
1040 if (options.protocol & SSH_PROTO_1) {
1041 if (options.server_key_bits < 512 ||
1042 options.server_key_bits > 32768) {
1043 fprintf(stderr, "Bad server key size.\n");
1047 * Check that server and host key lengths differ sufficiently. This
1048 * is necessary to make double encryption work with rsaref. Oh, I
1049 * hate software patents. I dont know if this can go? Niels
1051 if (options.server_key_bits >
1052 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1053 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1054 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1055 SSH_KEY_BITS_RESERVED) {
1056 options.server_key_bits =
1057 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1058 SSH_KEY_BITS_RESERVED;
1059 debug("Forcing server key to %d bits to make it differ from host key.",
1060 options.server_key_bits);
1068 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1069 fatal("Privilege separation user %s does not exist",
1071 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1072 (S_ISDIR(st.st_mode) == 0))
1073 fatal("Missing privilege separation directory: %s",
1074 _PATH_PRIVSEP_CHROOT_DIR);
1077 if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
1078 (st.st_uid != getuid () ||
1079 (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
1081 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1083 fatal("%s must be owned by root and not group or "
1084 "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
1087 /* Configuration looks good, so exit if in test mode. */
1092 ssh_gssapi_clean_env();
1096 * Clear out any supplemental groups we may have inherited. This
1097 * prevents inadvertent creation of files with bad modes (in the
1098 * portable version at least, it's certainly possible for PAM
1099 * to create a file, and we can't control the code in every
1100 * module which might be used).
1102 if (setgroups(0, NULL) < 0)
1103 debug("setgroups() failed: %.200s", strerror(errno));
1105 /* Initialize the log (it is reinitialized below in case we forked). */
1106 if (debug_flag && !inetd_flag)
1108 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1111 * If not in debugging mode, and not started from inetd, disconnect
1112 * from the controlling terminal, and fork. The original process
1115 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1118 #endif /* TIOCNOTTY */
1119 if (daemon(0, 0) < 0)
1120 fatal("daemon() failed: %.200s", strerror(errno));
1122 /* Disconnect from the controlling tty. */
1124 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
1126 (void) ioctl(fd, TIOCNOTTY, NULL);
1129 #endif /* TIOCNOTTY */
1131 /* Reinitialize the log (because of the fork above). */
1132 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1134 /* Initialize the random number generator. */
1137 /* Chdir to the root directory so that the current disk can be
1138 unmounted if desired. */
1141 /* ignore SIGPIPE */
1142 signal(SIGPIPE, SIG_IGN);
1144 /* Start listening for a socket, unless started from inetd. */
1147 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
1153 * We intentionally do not close the descriptors 0, 1, and 2
1154 * as our code for setting the descriptors won\'t work if
1155 * ttyfd happens to be one of those.
1157 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
1158 if (options.protocol & SSH_PROTO_1)
1159 generate_ephemeral_server_key();
1161 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1162 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1164 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1165 fatal("Too many listen sockets. "
1166 "Enlarge MAX_LISTEN_SOCKS");
1167 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
1168 ntop, sizeof(ntop), strport, sizeof(strport),
1169 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1170 error("getnameinfo failed");
1173 /* Create socket for listening. */
1174 listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
1175 if (listen_sock < 0) {
1176 /* kernel may not support ipv6 */
1177 verbose("socket: %.100s", strerror(errno));
1180 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
1181 error("listen_sock O_NONBLOCK: %s", strerror(errno));
1186 * Set socket options.
1187 * Allow local port reuse in TIME_WAIT.
1189 if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1190 &on, sizeof(on)) == -1)
1191 error("setsockopt SO_REUSEADDR: %s", strerror(errno));
1193 debug("Bind to port %s on %s.", strport, ntop);
1195 /* Bind the socket to the desired port. */
1196 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1198 error("Bind to port %s on %s failed: %.200s.",
1199 strport, ntop, strerror(errno));
1203 listen_socks[num_listen_socks] = listen_sock;
1206 /* Start listening on the port. */
1207 log("Server listening on %s port %s.", ntop, strport);
1208 if (listen(listen_sock, 5) < 0)
1209 fatal("listen: %.100s", strerror(errno));
1212 freeaddrinfo(options.listen_addrs);
1214 if (!num_listen_socks)
1215 fatal("Cannot bind any address.");
1217 if (options.protocol & SSH_PROTO_1)
1218 generate_ephemeral_server_key();
1221 * Arrange to restart on SIGHUP. The handler needs
1224 signal(SIGHUP, sighup_handler);
1226 signal(SIGTERM, sigterm_handler);
1227 signal(SIGQUIT, sigterm_handler);
1229 /* Arrange SIGCHLD to be caught. */
1230 signal(SIGCHLD, main_sigchld_handler);
1232 /* Write out the pid file after the sigterm handler is setup */
1235 * Record our pid in /var/run/sshd.pid to make it
1236 * easier to kill the correct sshd. We don't want to
1237 * do this before the bind above because the bind will
1238 * fail if there already is a daemon, and this will
1239 * overwrite any old pid in the file.
1241 f = fopen(options.pid_file, "wb");
1243 fprintf(f, "%ld\n", (long) getpid());
1248 /* setup fd set for listen */
1251 for (i = 0; i < num_listen_socks; i++)
1252 if (listen_socks[i] > maxfd)
1253 maxfd = listen_socks[i];
1254 /* pipes connected to unauthenticated childs */
1255 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1256 for (i = 0; i < options.max_startups; i++)
1257 startup_pipes[i] = -1;
1260 * Stay listening for connections until the system crashes or
1261 * the daemon is killed with a signal.
1264 if (received_sighup)
1268 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
1269 fdset = (fd_set *)xmalloc(fdsetsz);
1270 memset(fdset, 0, fdsetsz);
1272 for (i = 0; i < num_listen_socks; i++)
1273 FD_SET(listen_socks[i], fdset);
1274 for (i = 0; i < options.max_startups; i++)
1275 if (startup_pipes[i] != -1)
1276 FD_SET(startup_pipes[i], fdset);
1278 /* Wait in select until there is a connection. */
1279 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1280 if (ret < 0 && errno != EINTR)
1281 error("select: %.100s", strerror(errno));
1282 if (received_sigterm) {
1283 log("Received signal %d; terminating.",
1284 (int) received_sigterm);
1285 close_listen_socks();
1286 unlink(options.pid_file);
1289 if (key_used && key_do_regen) {
1290 generate_ephemeral_server_key();
1297 for (i = 0; i < options.max_startups; i++)
1298 if (startup_pipes[i] != -1 &&
1299 FD_ISSET(startup_pipes[i], fdset)) {
1301 * the read end of the pipe is ready
1302 * if the child has closed the pipe
1303 * after successful authentication
1304 * or if the child has died
1306 close(startup_pipes[i]);
1307 startup_pipes[i] = -1;
1310 for (i = 0; i < num_listen_socks; i++) {
1311 if (!FD_ISSET(listen_socks[i], fdset))
1313 fromlen = sizeof(from);
1314 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1317 if (errno != EINTR && errno != EWOULDBLOCK)
1318 error("accept: %.100s", strerror(errno));
1321 if (fcntl(newsock, F_SETFL, 0) < 0) {
1322 error("newsock del O_NONBLOCK: %s", strerror(errno));
1326 if (drop_connection(startups) == 1) {
1327 debug("drop connection #%d", startups);
1331 if (pipe(startup_p) == -1) {
1336 for (j = 0; j < options.max_startups; j++)
1337 if (startup_pipes[j] == -1) {
1338 startup_pipes[j] = startup_p[0];
1339 if (maxfd < startup_p[0])
1340 maxfd = startup_p[0];
1346 * Got connection. Fork a child to handle it, unless
1347 * we are in debugging mode.
1351 * In debugging mode. Close the listening
1352 * socket, and start processing the
1353 * connection without forking.
1355 debug("Server will not fork when running in debugging mode.");
1356 close_listen_socks();
1364 * Normal production daemon. Fork, and have
1365 * the child process the connection. The
1366 * parent continues listening.
1368 if ((pid = fork()) == 0) {
1370 * Child. Close the listening and max_startup
1371 * sockets. Start using the accepted socket.
1372 * Reinitialize logging (since our pid has
1373 * changed). We break out of the loop to handle
1376 startup_pipe = startup_p[1];
1377 close_startup_pipes();
1378 close_listen_socks();
1381 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1386 /* Parent. Stay in the loop. */
1388 error("fork: %.100s", strerror(errno));
1390 debug("Forked child %ld.", (long)pid);
1392 close(startup_p[1]);
1394 /* Mark that the key has been used (it was "given" to the child). */
1395 if ((options.protocol & SSH_PROTO_1) &&
1397 /* Schedule server key regeneration alarm. */
1398 signal(SIGALRM, key_regeneration_alarm);
1399 alarm(options.key_regeneration_time);
1405 /* Close the new socket (the child is now taking care of it). */
1408 /* child process check (or debug mode) */
1409 if (num_listen_socks < 0)
1414 /* This is the child processing a new connection. */
1417 * Create a new session and process group since the 4.4BSD
1418 * setlogin() affects the entire process group. We don't
1419 * want the child to be able to affect the parent.
1421 #if !defined(STREAMS_PUSH_ACQUIRES_CTTY)
1423 * If setsid is called on Solaris, sshd will acquire the controlling
1424 * terminal while pushing STREAMS modules. This will prevent the
1425 * shell from acquiring it later.
1427 if (!debug_flag && !inetd_flag && setsid() < 0)
1428 error("setsid: %.100s", strerror(errno));
1432 * Disable the key regeneration alarm. We will not regenerate the
1433 * key since we are no longer in a position to give it to anyone. We
1434 * will not restart on SIGHUP since it no longer makes sense.
1437 signal(SIGALRM, SIG_DFL);
1438 signal(SIGHUP, SIG_DFL);
1439 signal(SIGTERM, SIG_DFL);
1440 signal(SIGQUIT, SIG_DFL);
1441 signal(SIGCHLD, SIG_DFL);
1442 signal(SIGINT, SIG_DFL);
1444 /* Set keepalives if requested. */
1445 if (options.keepalives &&
1446 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
1448 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1451 * Register our connection. This turns encryption off because we do
1454 packet_set_connection(sock_in, sock_out);
1456 remote_port = get_remote_port();
1457 remote_ip = get_remote_ipaddr();
1460 /* Check whether logins are denied from this host. */
1462 struct request_info req;
1464 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
1467 if (!hosts_access(&req)) {
1468 debug("Connection refused by tcp wrapper");
1471 fatal("libwrap refuse returns");
1474 #endif /* LIBWRAP */
1476 /* Log the connection. */
1477 verbose("Connection from %.500s port %d", remote_ip, remote_port);
1480 * We don\'t want to listen forever unless the other side
1481 * successfully authenticates itself. So we set up an alarm which is
1482 * cleared after successful authentication. A limit of zero
1483 * indicates no limit. Note that we don\'t set the alarm in debugging
1484 * mode; it is just annoying to have the server exit just when you
1485 * are about to discover the bug.
1487 signal(SIGALRM, grace_alarm_handler);
1489 alarm(options.login_grace_time);
1491 sshd_exchange_identification(sock_in, sock_out);
1493 * Check that the connection comes from a privileged port.
1494 * Rhosts-Authentication only makes sense from privileged
1495 * programs. Of course, if the intruder has root access on his local
1496 * machine, he can connect from any port. So do not use these
1497 * authentication methods from machines that you do not trust.
1499 if (options.rhosts_authentication &&
1500 (remote_port >= IPPORT_RESERVED ||
1501 remote_port < IPPORT_RESERVED / 2)) {
1502 debug("Rhosts Authentication disabled, "
1503 "originating port %d not trusted.", remote_port);
1504 options.rhosts_authentication = 0;
1506 #if defined(KRB4) && !defined(KRB5)
1507 if (!packet_connection_is_ipv4() &&
1508 options.kerberos_authentication) {
1509 debug("Kerberos Authentication disabled, only available for IPv4.");
1510 options.kerberos_authentication = 0;
1512 #endif /* KRB4 && !KRB5 */
1513 #if defined(AFS) || defined(AFS_KRB5)
1514 /* If machine has AFS, set process authentication group. */
1519 #endif /* AFS || AFS_KRB5 */
1521 packet_set_nonblocking();
1524 if ((authctxt = privsep_preauth()) != NULL)
1527 /* perform the key exchange */
1528 /* authenticate user and start session */
1531 authctxt = do_authentication2();
1534 authctxt = do_authentication();
1537 * If we use privilege separation, the unprivileged child transfers
1538 * the current keystate and exits
1541 mm_send_keystate(pmonitor);
1547 * In privilege separation, we fork another child and prepare
1548 * file descriptor passing.
1551 privsep_postauth(authctxt);
1552 /* the monitor process [priv] will not return */
1554 destroy_sensitive_data();
1557 /* Perform session preparation. */
1558 do_authenticated(authctxt);
1560 /* The connection has been terminated. */
1561 verbose("Closing connection to %.100s", remote_ip);
1565 #endif /* USE_PAM */
1576 * Decrypt session_key_int using our private server key and private host key
1577 * (key with larger modulus first).
1580 ssh1_session_key(BIGNUM *session_key_int)
1584 if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
1585 /* Server key has bigger modulus. */
1586 if (BN_num_bits(sensitive_data.server_key->rsa->n) <
1587 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1588 fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1589 get_remote_ipaddr(),
1590 BN_num_bits(sensitive_data.server_key->rsa->n),
1591 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1592 SSH_KEY_BITS_RESERVED);
1594 if (rsa_private_decrypt(session_key_int, session_key_int,
1595 sensitive_data.server_key->rsa) <= 0)
1597 if (rsa_private_decrypt(session_key_int, session_key_int,
1598 sensitive_data.ssh1_host_key->rsa) <= 0)
1601 /* Host key has bigger modulus (or they are equal). */
1602 if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
1603 BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
1604 fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
1605 get_remote_ipaddr(),
1606 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
1607 BN_num_bits(sensitive_data.server_key->rsa->n),
1608 SSH_KEY_BITS_RESERVED);
1610 if (rsa_private_decrypt(session_key_int, session_key_int,
1611 sensitive_data.ssh1_host_key->rsa) < 0)
1613 if (rsa_private_decrypt(session_key_int, session_key_int,
1614 sensitive_data.server_key->rsa) < 0)
1627 BIGNUM *session_key_int;
1628 u_char session_key[SSH_SESSION_KEY_LENGTH];
1630 u_int cipher_type, auth_mask, protocol_flags;
1634 * Generate check bytes that the client must send back in the user
1635 * packet in order for it to be accepted; this is used to defy ip
1636 * spoofing attacks. Note that this only works against somebody
1637 * doing IP spoofing from a remote machine; any machine on the local
1638 * network can still see outgoing packets and catch the random
1639 * cookie. This only affects rhosts authentication, and this is one
1640 * of the reasons why it is inherently insecure.
1642 for (i = 0; i < 8; i++) {
1645 cookie[i] = rnd & 0xff;
1650 * Send our public key. We include in the packet 64 bits of random
1651 * data that must be matched in the reply in order to prevent IP
1654 packet_start(SSH_SMSG_PUBLIC_KEY);
1655 for (i = 0; i < 8; i++)
1656 packet_put_char(cookie[i]);
1658 /* Store our public server RSA key. */
1659 packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
1660 packet_put_bignum(sensitive_data.server_key->rsa->e);
1661 packet_put_bignum(sensitive_data.server_key->rsa->n);
1663 /* Store our public host RSA key. */
1664 packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1665 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
1666 packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
1668 /* Put protocol flags. */
1669 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1671 /* Declare which ciphers we support. */
1672 packet_put_int(cipher_mask_ssh1(0));
1674 /* Declare supported authentication types. */
1676 if (options.rhosts_authentication)
1677 auth_mask |= 1 << SSH_AUTH_RHOSTS;
1678 if (options.rhosts_rsa_authentication)
1679 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1680 if (options.rsa_authentication)
1681 auth_mask |= 1 << SSH_AUTH_RSA;
1682 #if defined(KRB4) || defined(KRB5)
1683 if (options.kerberos_authentication)
1684 auth_mask |= 1 << SSH_AUTH_KERBEROS;
1686 #if defined(AFS) || defined(KRB5)
1687 if (options.kerberos_tgt_passing)
1688 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
1691 if (options.afs_token_passing)
1692 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
1695 if (options.gss_authentication)
1696 auth_mask |= 1 << SSH_AUTH_GSSAPI;
1698 if (options.challenge_response_authentication == 1)
1699 auth_mask |= 1 << SSH_AUTH_TIS;
1700 if (options.password_authentication)
1701 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1702 packet_put_int(auth_mask);
1704 /* Send the packet and wait for it to be sent. */
1706 packet_write_wait();
1708 debug("Sent %d bit server key and %d bit host key.",
1709 BN_num_bits(sensitive_data.server_key->rsa->n),
1710 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1712 /* Read clients reply (cipher type and session key). */
1713 packet_read_expect(SSH_CMSG_SESSION_KEY);
1715 /* Get cipher type and check whether we accept this. */
1716 cipher_type = packet_get_char();
1718 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1719 packet_disconnect("Warning: client selects unsupported cipher.");
1721 /* Get check bytes from the packet. These must match those we
1722 sent earlier with the public key packet. */
1723 for (i = 0; i < 8; i++)
1724 if (cookie[i] != packet_get_char())
1725 packet_disconnect("IP Spoofing check bytes do not match.");
1727 debug("Encryption type: %.200s", cipher_name(cipher_type));
1729 /* Get the encrypted integer. */
1730 if ((session_key_int = BN_new()) == NULL)
1731 fatal("do_ssh1_kex: BN_new failed");
1732 packet_get_bignum(session_key_int);
1734 protocol_flags = packet_get_int();
1735 packet_set_protocol_flags(protocol_flags);
1738 /* Decrypt session_key_int using host/server keys */
1739 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1742 * Extract session key from the decrypted integer. The key is in the
1743 * least significant 256 bits of the integer; the first byte of the
1744 * key is in the highest bits.
1747 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1748 len = BN_num_bytes(session_key_int);
1749 if (len < 0 || len > sizeof(session_key)) {
1750 error("do_connection: bad session key len from %s: "
1751 "session_key_int %d > sizeof(session_key) %lu",
1752 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
1755 memset(session_key, 0, sizeof(session_key));
1756 BN_bn2bin(session_key_int,
1757 session_key + sizeof(session_key) - len);
1759 compute_session_id(session_id, cookie,
1760 sensitive_data.ssh1_host_key->rsa->n,
1761 sensitive_data.server_key->rsa->n);
1763 * Xor the first 16 bytes of the session key with the
1766 for (i = 0; i < 16; i++)
1767 session_key[i] ^= session_id[i];
1771 int bytes = BN_num_bytes(session_key_int);
1772 u_char *buf = xmalloc(bytes);
1775 log("do_connection: generating a fake encryption key");
1776 BN_bn2bin(session_key_int, buf);
1778 MD5_Update(&md, buf, bytes);
1779 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1780 MD5_Final(session_key, &md);
1782 MD5_Update(&md, session_key, 16);
1783 MD5_Update(&md, buf, bytes);
1784 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1785 MD5_Final(session_key + 16, &md);
1786 memset(buf, 0, bytes);
1788 for (i = 0; i < 16; i++)
1789 session_id[i] = session_key[i] ^ session_key[i + 16];
1794 * Before we destroy the host and server keys, hash them so we can
1795 * send the hash over to the client via a secure channel so that it
1801 unsigned char *data;
1802 unsigned int data_len;
1803 extern unsigned char ssh1_key_digest[16]; /* in gss-genr.c */
1806 debug("Calculating MD5 hash of server and host keys...");
1808 /* Write all the keys to a temporary buffer */
1812 buffer_put_bignum(&buf, sensitive_data.server_key->rsa->e);
1813 buffer_put_bignum(&buf, sensitive_data.server_key->rsa->n);
1816 buffer_put_bignum(&buf, sensitive_data.ssh1_host_key->rsa->e);
1817 buffer_put_bignum(&buf, sensitive_data.ssh1_host_key->rsa->n);
1819 /* Get the resulting data */
1820 data = (unsigned char *) buffer_ptr(&buf);
1821 data_len = buffer_len(&buf);
1824 MD5_Init(&md5context);
1825 MD5_Update(&md5context, data, data_len);
1826 MD5_Final(ssh1_key_digest, &md5context);
1834 /* Destroy the private and public keys. No longer. */
1835 destroy_sensitive_data();
1838 mm_ssh1_session_id(session_id);
1840 /* Destroy the decrypted integer. It is no longer needed. */
1841 BN_clear_free(session_key_int);
1843 /* Set the session key. From this on all communications will be encrypted. */
1844 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1846 /* Destroy our copy of the session key. It is no longer needed. */
1847 memset(session_key, 0, sizeof(session_key));
1849 debug("Received session key; encryption turned on.");
1851 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
1852 packet_start(SSH_SMSG_SUCCESS);
1854 packet_write_wait();
1858 * SSH2 key exchange: diffie-hellman-group1-sha1
1865 if (options.ciphers != NULL) {
1866 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1867 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1869 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1870 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
1871 myproposal[PROPOSAL_ENC_ALGS_STOC] =
1872 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1874 if (options.macs != NULL) {
1875 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1876 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1878 if (!options.compression) {
1879 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1880 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1882 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1888 char *newstr = NULL;
1889 orig = myproposal[PROPOSAL_KEX_ALGS];
1891 /* If we don't have a host key, then all of the algorithms
1892 * currently in myproposal are useless */
1893 if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])==0)
1896 if (options.gss_keyex)
1897 gss = ssh_server_gssapi_mechanisms();
1902 int len = strlen(orig) + strlen(gss) +2;
1903 newstr=xmalloc(len);
1904 snprintf(newstr,len,"%s,%s",gss,orig);
1910 /* If we've got GSSAPI mechanisms, then we've also got the 'null'
1911 host key algorithm, but we're not allowed to advertise it, unless
1912 its the only host key algorithm we're supporting */
1913 if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) {
1914 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]="null";
1917 myproposal[PROPOSAL_KEX_ALGS]=newstr;
1919 fatal("No supported key exchange algorithms");
1923 /* start key exchange */
1924 kex = kex_setup(myproposal);
1925 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
1926 kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
1928 kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
1931 kex->client_version_string=client_version_string;
1932 kex->server_version_string=server_version_string;
1933 kex->load_host_key=&get_hostkey_by_type;
1934 kex->host_key_index=&get_hostkey_index;
1938 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1940 session_id2 = kex->session_id;
1941 session_id2_len = kex->session_id_len;
1944 /* send 1st encrypted/maced/compressed message */
1945 packet_start(SSH2_MSG_IGNORE);
1946 packet_put_cstring("markus");
1948 packet_write_wait();