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 1.251 2002/06/25 18:51:04 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 = _PATH_SERVER_CONFIG_FILE;
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 */
214 extern struct monitor *pmonitor;
215 extern int use_privsep;
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 /* Close the connection. */
318 /* Log error and exit. */
319 fatal("Timeout before authentication for %s.", get_remote_ipaddr());
323 * Signal handler for the key regeneration alarm. Note that this
324 * alarm only occurs in the daemon waiting for connections, and it does not
325 * do anything with the private key or random state before forking.
326 * Thus there should be no concurrency control/asynchronous execution
330 generate_ephemeral_server_key(void)
335 verbose("Generating %s%d bit RSA key.",
336 sensitive_data.server_key ? "new " : "", options.server_key_bits);
337 if (sensitive_data.server_key != NULL)
338 key_free(sensitive_data.server_key);
339 sensitive_data.server_key = key_generate(KEY_RSA1,
340 options.server_key_bits);
341 verbose("RSA key generation complete.");
343 for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
346 sensitive_data.ssh1_cookie[i] = rand & 0xff;
353 key_regeneration_alarm(int sig)
355 int save_errno = errno;
357 signal(SIGALRM, SIG_DFL);
363 sshd_exchange_identification(int sock_in, int sock_out)
366 int remote_major, remote_minor;
369 char buf[256]; /* Must not be larger than remote_version. */
370 char remote_version[256]; /* Must be at least as big as buf. */
372 if ((options.protocol & SSH_PROTO_1) &&
373 (options.protocol & SSH_PROTO_2)) {
374 major = PROTOCOL_MAJOR_1;
376 } else if (options.protocol & SSH_PROTO_2) {
377 major = PROTOCOL_MAJOR_2;
378 minor = PROTOCOL_MINOR_2;
380 major = PROTOCOL_MAJOR_1;
381 minor = PROTOCOL_MINOR_1;
383 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
384 server_version_string = xstrdup(buf);
386 if (client_version_string == NULL) {
387 /* Send our protocol version identification. */
388 if (atomicio(write, sock_out, server_version_string,
389 strlen(server_version_string))
390 != strlen(server_version_string)) {
391 log("Could not write ident string to %s", get_remote_ipaddr());
395 /* Read other sides version identification. */
396 memset(buf, 0, sizeof(buf));
397 for (i = 0; i < sizeof(buf) - 1; i++) {
398 if (atomicio(read, sock_in, &buf[i], 1) != 1) {
399 log("Did not receive identification string from %s",
400 get_remote_ipaddr());
403 if (buf[i] == '\r') {
405 /* Kludge for F-Secure Macintosh < 1.0.2 */
407 strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
411 if (buf[i] == '\n') {
416 buf[sizeof(buf) - 1] = 0;
417 client_version_string = xstrdup(buf);
421 * Check that the versions match. In future this might accept
422 * several versions and set appropriate flags to handle them.
424 if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
425 &remote_major, &remote_minor, remote_version) != 3) {
426 s = "Protocol mismatch.\n";
427 (void) atomicio(write, sock_out, s, strlen(s));
430 log("Bad protocol version identification '%.100s' from %s",
431 client_version_string, get_remote_ipaddr());
434 debug("Client protocol version %d.%d; client software version %.100s",
435 remote_major, remote_minor, remote_version);
437 compat_datafellows(remote_version);
439 if (datafellows & SSH_BUG_SCANNER) {
440 log("scanned from %s with %s. Don't panic.",
441 get_remote_ipaddr(), client_version_string);
446 switch (remote_major) {
448 if (remote_minor == 99) {
449 if (options.protocol & SSH_PROTO_2)
455 if (!(options.protocol & SSH_PROTO_1)) {
459 if (remote_minor < 3) {
460 packet_disconnect("Your ssh version is too old and "
461 "is no longer supported. Please install a newer version.");
462 } else if (remote_minor == 3) {
463 /* note that this disables agent-forwarding */
468 if (options.protocol & SSH_PROTO_2) {
477 chop(server_version_string);
478 debug("Local version string %.200s", server_version_string);
481 s = "Protocol major versions differ.\n";
482 (void) atomicio(write, sock_out, s, strlen(s));
485 log("Protocol major versions differ for %s: %.200s vs. %.200s",
487 server_version_string, client_version_string);
492 /* Destroy the host and server keys. They will no longer be needed. */
494 destroy_sensitive_data(void)
498 if (sensitive_data.server_key) {
499 key_free(sensitive_data.server_key);
500 sensitive_data.server_key = NULL;
502 for (i = 0; i < options.num_host_key_files; i++) {
503 if (sensitive_data.host_keys[i]) {
504 key_free(sensitive_data.host_keys[i]);
505 sensitive_data.host_keys[i] = NULL;
508 sensitive_data.ssh1_host_key = NULL;
509 memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
512 /* Demote private to public keys for network child */
514 demote_sensitive_data(void)
519 if (sensitive_data.server_key) {
520 tmp = key_demote(sensitive_data.server_key);
521 key_free(sensitive_data.server_key);
522 sensitive_data.server_key = tmp;
525 for (i = 0; i < options.num_host_key_files; i++) {
526 if (sensitive_data.host_keys[i]) {
527 tmp = key_demote(sensitive_data.host_keys[i]);
528 key_free(sensitive_data.host_keys[i]);
529 sensitive_data.host_keys[i] = tmp;
530 if (tmp->type == KEY_RSA1)
531 sensitive_data.ssh1_host_key = tmp;
535 /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */
539 privsep_preauth_child(void)
546 /* Enable challenge-response authentication for privilege separation */
547 privsep_challenge_enable();
549 for (i = 0; i < 256; i++)
550 rand[i] = arc4random();
551 RAND_seed(rand, sizeof(rand));
553 /* Demote the private keys to public keys. */
554 demote_sensitive_data();
556 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
557 fatal("Privilege separation user %s does not exist",
559 memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
562 /* Change our root directory*/
563 if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
564 fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
566 if (chdir("/") == -1)
567 fatal("chdir(\"/\"): %s", strerror(errno));
569 /* Drop our privileges */
570 debug3("privsep user:group %u:%u", (u_int)pw->pw_uid,
573 /* XXX not ready, to heavy after chroot */
574 do_setusercontext(pw);
576 gidset[0] = pw->pw_gid;
577 if (setgid(pw->pw_gid) < 0)
578 fatal("setgid failed for %u", pw->pw_gid );
579 if (setgroups(1, gidset) < 0)
580 fatal("setgroups: %.100s", strerror(errno));
581 permanently_set_uid(pw);
586 privsep_preauth(void)
588 Authctxt *authctxt = NULL;
592 /* Set up unprivileged child process to deal with network data */
593 pmonitor = monitor_init();
594 /* Store a pointer to the kex for later rekeying */
595 pmonitor->m_pkex = &xxx_kex;
599 fatal("fork of unprivileged child failed");
600 } else if (pid != 0) {
601 debug2("Network child is on pid %ld", (long)pid);
603 close(pmonitor->m_recvfd);
604 authctxt = monitor_child_preauth(pmonitor);
605 close(pmonitor->m_sendfd);
608 monitor_sync(pmonitor);
610 /* Wait for the child's exit status */
611 while (waitpid(pid, &status, 0) < 0)
618 close(pmonitor->m_sendfd);
620 /* Demote the child */
621 if (getuid() == 0 || geteuid() == 0)
622 privsep_preauth_child();
623 setproctitle("%s", "[net]");
629 privsep_postauth(Authctxt *authctxt)
631 extern Authctxt *x_authctxt;
633 /* XXX - Remote port forwarding */
634 x_authctxt = authctxt;
636 #ifdef BROKEN_FD_PASSING
639 if (authctxt->pw->pw_uid == 0 || options.use_login) {
641 /* File descriptor passing is broken or root login */
642 monitor_apply_keystate(pmonitor);
647 /* Authentication complete */
649 if (startup_pipe != -1) {
654 /* New socket pair */
655 monitor_reinit(pmonitor);
657 pmonitor->m_pid = fork();
658 if (pmonitor->m_pid == -1)
659 fatal("fork of unprivileged child failed");
660 else if (pmonitor->m_pid != 0) {
661 debug2("User child is on pid %ld", (long)pmonitor->m_pid);
662 close(pmonitor->m_recvfd);
663 monitor_child_postauth(pmonitor);
669 close(pmonitor->m_sendfd);
671 /* Demote the private keys to public keys. */
672 demote_sensitive_data();
674 /* Drop privileges */
675 do_setusercontext(authctxt->pw);
677 /* It is safe now to apply the key state */
678 monitor_apply_keystate(pmonitor);
682 list_hostkey_types(void)
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;
813 struct linger linger;
815 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
816 int listen_sock, maxfd;
821 int ret, key_used = 0;
823 #ifdef HAVE_SECUREWARE
824 (void)set_auth_parameters(ac, av);
826 __progname = get_progname(av[0]);
833 /* Initialize configuration options to their default values. */
834 initialize_server_options(&options);
836 /* Parse command-line arguments. */
837 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:o:dDeiqtQ46")) != -1) {
846 config_file_name = optarg;
849 if (0 == debug_flag) {
851 options.log_level = SYSLOG_LEVEL_DEBUG1;
852 } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
855 fprintf(stderr, "Too high debugging level.\n");
872 options.log_level = SYSLOG_LEVEL_QUIET;
875 options.server_key_bits = atoi(optarg);
878 options.ports_from_cmdline = 1;
879 if (options.num_ports >= MAX_PORTS) {
880 fprintf(stderr, "too many ports.\n");
883 options.ports[options.num_ports++] = a2port(optarg);
884 if (options.ports[options.num_ports-1] == 0) {
885 fprintf(stderr, "Bad port number.\n");
890 if ((options.login_grace_time = convtime(optarg)) == -1) {
891 fprintf(stderr, "Invalid login grace time.\n");
896 if ((options.key_regeneration_time = convtime(optarg)) == -1) {
897 fprintf(stderr, "Invalid key regeneration interval.\n");
902 if (options.num_host_key_files >= MAX_HOSTKEYS) {
903 fprintf(stderr, "too many host keys.\n");
906 options.host_key_files[options.num_host_key_files++] = optarg;
909 client_version_string = optarg;
910 /* only makes sense with inetd_flag, i.e. no listen() */
917 utmp_len = atoi(optarg);
920 if (process_server_config_line(&options, optarg,
921 "command-line", 0) != 0)
930 SSLeay_add_all_algorithms();
931 channel_set_af(IPv4or6);
934 * Force logging to stderr until we have loaded the private host
935 * key (unless started from inetd)
938 options.log_level == SYSLOG_LEVEL_NOT_SET ?
939 SYSLOG_LEVEL_INFO : options.log_level,
940 options.log_facility == SYSLOG_FACILITY_NOT_SET ?
941 SYSLOG_FACILITY_AUTH : options.log_facility,
945 /* Cray can define user privs drop all prives now!
946 * Not needed on PRIV_SU systems!
953 /* Read server configuration options from the configuration file. */
954 read_server_config(&options, config_file_name);
956 /* Fill in default values for those options not explicitly set. */
957 fill_default_server_options(&options);
959 /* Check that there are no remaining arguments. */
961 fprintf(stderr, "Extra argument %s.\n", av[optind]);
965 debug("sshd version %.100s", SSH_VERSION);
967 /* load private host keys */
968 sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*));
969 for (i = 0; i < options.num_host_key_files; i++)
970 sensitive_data.host_keys[i] = NULL;
971 sensitive_data.server_key = NULL;
972 sensitive_data.ssh1_host_key = NULL;
973 sensitive_data.have_ssh1_key = 0;
974 sensitive_data.have_ssh2_key = 0;
976 for (i = 0; i < options.num_host_key_files; i++) {
977 key = key_load_private(options.host_key_files[i], "", NULL);
978 sensitive_data.host_keys[i] = key;
980 error("Could not load host key: %s",
981 options.host_key_files[i]);
982 sensitive_data.host_keys[i] = NULL;
987 sensitive_data.ssh1_host_key = key;
988 sensitive_data.have_ssh1_key = 1;
992 sensitive_data.have_ssh2_key = 1;
995 debug("private host key: #%d type %d %s", i, key->type,
998 if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
999 log("Disabling protocol version 1. Could not load host key");
1000 options.protocol &= ~SSH_PROTO_1;
1003 /* The GSSAPI key exchange can run without a host key */
1004 if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
1005 log("Disabling protocol version 2. Could not load host key");
1006 options.protocol &= ~SSH_PROTO_2;
1009 if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
1010 log("sshd: no hostkeys available -- exiting.");
1014 /* Check certain values for sanity. */
1015 if (options.protocol & SSH_PROTO_1) {
1016 if (options.server_key_bits < 512 ||
1017 options.server_key_bits > 32768) {
1018 fprintf(stderr, "Bad server key size.\n");
1022 * Check that server and host key lengths differ sufficiently. This
1023 * is necessary to make double encryption work with rsaref. Oh, I
1024 * hate software patents. I dont know if this can go? Niels
1026 if (options.server_key_bits >
1027 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
1028 SSH_KEY_BITS_RESERVED && options.server_key_bits <
1029 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1030 SSH_KEY_BITS_RESERVED) {
1031 options.server_key_bits =
1032 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
1033 SSH_KEY_BITS_RESERVED;
1034 debug("Forcing server key to %d bits to make it differ from host key.",
1035 options.server_key_bits);
1043 if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
1044 fatal("Privilege separation user %s does not exist",
1046 if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
1047 (S_ISDIR(st.st_mode) == 0))
1048 fatal("Missing privilege separation directory: %s",
1049 _PATH_PRIVSEP_CHROOT_DIR);
1050 if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
1051 fatal("Bad owner or mode for %s",
1052 _PATH_PRIVSEP_CHROOT_DIR);
1055 /* Configuration looks good, so exit if in test mode. */
1060 ssh_gssapi_clean_env();
1065 #endif /* MECHGLUE */
1068 * Clear out any supplemental groups we may have inherited. This
1069 * prevents inadvertent creation of files with bad modes (in the
1070 * portable version at least, it's certainly possible for PAM
1071 * to create a file, and we can't control the code in every
1072 * module which might be used).
1074 if (setgroups(0, NULL) < 0)
1075 debug("setgroups() failed: %.200s", strerror(errno));
1077 /* Initialize the log (it is reinitialized below in case we forked). */
1078 if (debug_flag && !inetd_flag)
1080 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1083 * If not in debugging mode, and not started from inetd, disconnect
1084 * from the controlling terminal, and fork. The original process
1087 if (!(debug_flag || inetd_flag || no_daemon_flag)) {
1090 #endif /* TIOCNOTTY */
1091 if (daemon(0, 0) < 0)
1092 fatal("daemon() failed: %.200s", strerror(errno));
1094 /* Disconnect from the controlling tty. */
1096 fd = open(_PATH_TTY, O_RDWR | O_NOCTTY);
1098 (void) ioctl(fd, TIOCNOTTY, NULL);
1101 #endif /* TIOCNOTTY */
1103 /* Reinitialize the log (because of the fork above). */
1104 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1106 /* Initialize the random number generator. */
1109 /* Chdir to the root directory so that the current disk can be
1110 unmounted if desired. */
1113 /* ignore SIGPIPE */
1114 signal(SIGPIPE, SIG_IGN);
1116 /* Start listening for a socket, unless started from inetd. */
1119 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
1125 * We intentionally do not close the descriptors 0, 1, and 2
1126 * as our code for setting the descriptors won\'t work if
1127 * ttyfd happens to be one of those.
1129 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
1130 if (options.protocol & SSH_PROTO_1)
1131 generate_ephemeral_server_key();
1133 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
1134 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
1136 if (num_listen_socks >= MAX_LISTEN_SOCKS)
1137 fatal("Too many listen sockets. "
1138 "Enlarge MAX_LISTEN_SOCKS");
1139 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
1140 ntop, sizeof(ntop), strport, sizeof(strport),
1141 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
1142 error("getnameinfo failed");
1145 /* Create socket for listening. */
1146 listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
1147 if (listen_sock < 0) {
1148 /* kernel may not support ipv6 */
1149 verbose("socket: %.100s", strerror(errno));
1152 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
1153 error("listen_sock O_NONBLOCK: %s", strerror(errno));
1158 * Set socket options. We try to make the port
1159 * reusable and have it close as fast as possible
1160 * without waiting in unnecessary wait states on
1163 setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
1166 linger.l_linger = 5;
1167 setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
1168 &linger, sizeof(linger));
1170 debug("Bind to port %s on %s.", strport, ntop);
1172 /* Bind the socket to the desired port. */
1173 if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
1175 error("Bind to port %s on %s failed: %.200s.",
1176 strport, ntop, strerror(errno));
1180 listen_socks[num_listen_socks] = listen_sock;
1183 /* Start listening on the port. */
1184 log("Server listening on %s port %s.", ntop, strport);
1185 if (listen(listen_sock, 5) < 0)
1186 fatal("listen: %.100s", strerror(errno));
1189 freeaddrinfo(options.listen_addrs);
1191 if (!num_listen_socks)
1192 fatal("Cannot bind any address.");
1194 if (options.protocol & SSH_PROTO_1)
1195 generate_ephemeral_server_key();
1198 * Arrange to restart on SIGHUP. The handler needs
1201 signal(SIGHUP, sighup_handler);
1203 signal(SIGTERM, sigterm_handler);
1204 signal(SIGQUIT, sigterm_handler);
1206 /* Arrange SIGCHLD to be caught. */
1207 signal(SIGCHLD, main_sigchld_handler);
1209 /* Write out the pid file after the sigterm handler is setup */
1212 * Record our pid in /var/run/sshd.pid to make it
1213 * easier to kill the correct sshd. We don't want to
1214 * do this before the bind above because the bind will
1215 * fail if there already is a daemon, and this will
1216 * overwrite any old pid in the file.
1218 f = fopen(options.pid_file, "wb");
1220 fprintf(f, "%ld\n", (long) getpid());
1225 /* setup fd set for listen */
1228 for (i = 0; i < num_listen_socks; i++)
1229 if (listen_socks[i] > maxfd)
1230 maxfd = listen_socks[i];
1231 /* pipes connected to unauthenticated childs */
1232 startup_pipes = xmalloc(options.max_startups * sizeof(int));
1233 for (i = 0; i < options.max_startups; i++)
1234 startup_pipes[i] = -1;
1237 * Stay listening for connections until the system crashes or
1238 * the daemon is killed with a signal.
1241 if (received_sighup)
1245 fdsetsz = howmany(maxfd+1, NFDBITS) * sizeof(fd_mask);
1246 fdset = (fd_set *)xmalloc(fdsetsz);
1247 memset(fdset, 0, fdsetsz);
1249 for (i = 0; i < num_listen_socks; i++)
1250 FD_SET(listen_socks[i], fdset);
1251 for (i = 0; i < options.max_startups; i++)
1252 if (startup_pipes[i] != -1)
1253 FD_SET(startup_pipes[i], fdset);
1255 /* Wait in select until there is a connection. */
1256 ret = select(maxfd+1, fdset, NULL, NULL, NULL);
1257 if (ret < 0 && errno != EINTR)
1258 error("select: %.100s", strerror(errno));
1259 if (received_sigterm) {
1260 log("Received signal %d; terminating.",
1261 (int) received_sigterm);
1262 close_listen_socks();
1263 unlink(options.pid_file);
1266 if (key_used && key_do_regen) {
1267 generate_ephemeral_server_key();
1274 for (i = 0; i < options.max_startups; i++)
1275 if (startup_pipes[i] != -1 &&
1276 FD_ISSET(startup_pipes[i], fdset)) {
1278 * the read end of the pipe is ready
1279 * if the child has closed the pipe
1280 * after successful authentication
1281 * or if the child has died
1283 close(startup_pipes[i]);
1284 startup_pipes[i] = -1;
1287 for (i = 0; i < num_listen_socks; i++) {
1288 if (!FD_ISSET(listen_socks[i], fdset))
1290 fromlen = sizeof(from);
1291 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
1294 if (errno != EINTR && errno != EWOULDBLOCK)
1295 error("accept: %.100s", strerror(errno));
1298 if (fcntl(newsock, F_SETFL, 0) < 0) {
1299 error("newsock del O_NONBLOCK: %s", strerror(errno));
1303 if (drop_connection(startups) == 1) {
1304 debug("drop connection #%d", startups);
1308 if (pipe(startup_p) == -1) {
1313 for (j = 0; j < options.max_startups; j++)
1314 if (startup_pipes[j] == -1) {
1315 startup_pipes[j] = startup_p[0];
1316 if (maxfd < startup_p[0])
1317 maxfd = startup_p[0];
1323 * Got connection. Fork a child to handle it, unless
1324 * we are in debugging mode.
1328 * In debugging mode. Close the listening
1329 * socket, and start processing the
1330 * connection without forking.
1332 debug("Server will not fork when running in debugging mode.");
1333 close_listen_socks();
1341 * Normal production daemon. Fork, and have
1342 * the child process the connection. The
1343 * parent continues listening.
1345 if ((pid = fork()) == 0) {
1347 * Child. Close the listening and max_startup
1348 * sockets. Start using the accepted socket.
1349 * Reinitialize logging (since our pid has
1350 * changed). We break out of the loop to handle
1353 startup_pipe = startup_p[1];
1354 close_startup_pipes();
1355 close_listen_socks();
1358 log_init(__progname, options.log_level, options.log_facility, log_stderr);
1363 /* Parent. Stay in the loop. */
1365 error("fork: %.100s", strerror(errno));
1367 debug("Forked child %ld.", (long)pid);
1369 close(startup_p[1]);
1371 /* Mark that the key has been used (it was "given" to the child). */
1372 if ((options.protocol & SSH_PROTO_1) &&
1374 /* Schedule server key regeneration alarm. */
1375 signal(SIGALRM, key_regeneration_alarm);
1376 alarm(options.key_regeneration_time);
1382 /* Close the new socket (the child is now taking care of it). */
1385 /* child process check (or debug mode) */
1386 if (num_listen_socks < 0)
1391 /* This is the child processing a new connection. */
1394 * Create a new session and process group since the 4.4BSD
1395 * setlogin() affects the entire process group. We don't
1396 * want the child to be able to affect the parent.
1399 /* XXX: this breaks Solaris */
1400 if (!debug_flag && !inetd_flag && setsid() < 0)
1401 error("setsid: %.100s", strerror(errno));
1405 * Disable the key regeneration alarm. We will not regenerate the
1406 * key since we are no longer in a position to give it to anyone. We
1407 * will not restart on SIGHUP since it no longer makes sense.
1410 signal(SIGALRM, SIG_DFL);
1411 signal(SIGHUP, SIG_DFL);
1412 signal(SIGTERM, SIG_DFL);
1413 signal(SIGQUIT, SIG_DFL);
1414 signal(SIGCHLD, SIG_DFL);
1415 signal(SIGINT, SIG_DFL);
1418 * Set socket options for the connection. We want the socket to
1419 * close as fast as possible without waiting for anything. If the
1420 * connection is not a socket, these will do nothing.
1422 /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
1424 linger.l_linger = 5;
1425 setsockopt(sock_in, SOL_SOCKET, SO_LINGER, &linger, sizeof(linger));
1427 /* Set keepalives if requested. */
1428 if (options.keepalives &&
1429 setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
1431 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1434 * Register our connection. This turns encryption off because we do
1437 packet_set_connection(sock_in, sock_out);
1439 remote_port = get_remote_port();
1440 remote_ip = get_remote_ipaddr();
1443 /* Check whether logins are denied from this host. */
1445 struct request_info req;
1447 request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
1450 if (!hosts_access(&req)) {
1451 debug("Connection refused by tcp wrapper");
1454 fatal("libwrap refuse returns");
1457 #endif /* LIBWRAP */
1459 /* Log the connection. */
1460 verbose("Connection from %.500s port %d", remote_ip, remote_port);
1463 * We don\'t want to listen forever unless the other side
1464 * successfully authenticates itself. So we set up an alarm which is
1465 * cleared after successful authentication. A limit of zero
1466 * indicates no limit. Note that we don\'t set the alarm in debugging
1467 * mode; it is just annoying to have the server exit just when you
1468 * are about to discover the bug.
1470 signal(SIGALRM, grace_alarm_handler);
1472 alarm(options.login_grace_time);
1474 sshd_exchange_identification(sock_in, sock_out);
1476 * Check that the connection comes from a privileged port.
1477 * Rhosts-Authentication only makes sense from privileged
1478 * programs. Of course, if the intruder has root access on his local
1479 * machine, he can connect from any port. So do not use these
1480 * authentication methods from machines that you do not trust.
1482 if (options.rhosts_authentication &&
1483 (remote_port >= IPPORT_RESERVED ||
1484 remote_port < IPPORT_RESERVED / 2)) {
1485 debug("Rhosts Authentication disabled, "
1486 "originating port %d not trusted.", remote_port);
1487 options.rhosts_authentication = 0;
1489 #if defined(KRB4) && !defined(KRB5)
1490 if (!packet_connection_is_ipv4() &&
1491 options.kerberos_authentication) {
1492 debug("Kerberos Authentication disabled, only available for IPv4.");
1493 options.kerberos_authentication = 0;
1495 #endif /* KRB4 && !KRB5 */
1497 /* If machine has AFS, set process authentication group. */
1504 packet_set_nonblocking();
1507 if ((authctxt = privsep_preauth()) != NULL)
1510 /* perform the key exchange */
1511 /* authenticate user and start session */
1514 authctxt = do_authentication2();
1517 authctxt = do_authentication();
1520 * If we use privilege separation, the unprivileged child transfers
1521 * the current keystate and exits
1524 mm_send_keystate(pmonitor);
1530 * In privilege separation, we fork another child and prepare
1531 * file descriptor passing.
1534 privsep_postauth(authctxt);
1535 /* the monitor process [priv] will not return */
1537 destroy_sensitive_data();
1540 /* Perform session preparation. */
1541 do_authenticated(authctxt);
1543 /* The connection has been terminated. */
1544 verbose("Closing connection to %.100s", remote_ip);
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++) {
1627 rand = arc4random();
1628 cookie[i] = rand & 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;
1678 if (options.gss_authentication)
1679 auth_mask |= 1 << SSH_AUTH_GSSAPI;
1681 if (options.challenge_response_authentication == 1)
1682 auth_mask |= 1 << SSH_AUTH_TIS;
1683 if (options.password_authentication)
1684 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1685 packet_put_int(auth_mask);
1687 /* Send the packet and wait for it to be sent. */
1689 packet_write_wait();
1691 debug("Sent %d bit server key and %d bit host key.",
1692 BN_num_bits(sensitive_data.server_key->rsa->n),
1693 BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
1695 /* Read clients reply (cipher type and session key). */
1696 packet_read_expect(SSH_CMSG_SESSION_KEY);
1698 /* Get cipher type and check whether we accept this. */
1699 cipher_type = packet_get_char();
1701 if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
1702 packet_disconnect("Warning: client selects unsupported cipher.");
1704 /* Get check bytes from the packet. These must match those we
1705 sent earlier with the public key packet. */
1706 for (i = 0; i < 8; i++)
1707 if (cookie[i] != packet_get_char())
1708 packet_disconnect("IP Spoofing check bytes do not match.");
1710 debug("Encryption type: %.200s", cipher_name(cipher_type));
1712 /* Get the encrypted integer. */
1713 if ((session_key_int = BN_new()) == NULL)
1714 fatal("do_ssh1_kex: BN_new failed");
1715 packet_get_bignum(session_key_int);
1717 protocol_flags = packet_get_int();
1718 packet_set_protocol_flags(protocol_flags);
1721 /* Decrypt session_key_int using host/server keys */
1722 rsafail = PRIVSEP(ssh1_session_key(session_key_int));
1725 * Extract session key from the decrypted integer. The key is in the
1726 * least significant 256 bits of the integer; the first byte of the
1727 * key is in the highest bits.
1730 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1731 len = BN_num_bytes(session_key_int);
1732 if (len < 0 || len > sizeof(session_key)) {
1733 error("do_connection: bad session key len from %s: "
1734 "session_key_int %d > sizeof(session_key) %lu",
1735 get_remote_ipaddr(), len, (u_long)sizeof(session_key));
1738 memset(session_key, 0, sizeof(session_key));
1739 BN_bn2bin(session_key_int,
1740 session_key + sizeof(session_key) - len);
1742 compute_session_id(session_id, cookie,
1743 sensitive_data.ssh1_host_key->rsa->n,
1744 sensitive_data.server_key->rsa->n);
1746 * Xor the first 16 bytes of the session key with the
1749 for (i = 0; i < 16; i++)
1750 session_key[i] ^= session_id[i];
1754 int bytes = BN_num_bytes(session_key_int);
1755 u_char *buf = xmalloc(bytes);
1758 log("do_connection: generating a fake encryption key");
1759 BN_bn2bin(session_key_int, buf);
1761 MD5_Update(&md, buf, bytes);
1762 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1763 MD5_Final(session_key, &md);
1765 MD5_Update(&md, session_key, 16);
1766 MD5_Update(&md, buf, bytes);
1767 MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
1768 MD5_Final(session_key + 16, &md);
1769 memset(buf, 0, bytes);
1771 for (i = 0; i < 16; i++)
1772 session_id[i] = session_key[i] ^ session_key[i + 16];
1777 * Before we destroy the host and server keys, hash them so we can
1778 * send the hash over to the client via a secure channel so that it
1784 unsigned char *data;
1785 unsigned int data_len;
1786 extern unsigned char ssh1_key_digest[16]; /* in gss-genr.c */
1789 debug("Calculating MD5 hash of server and host keys...");
1791 /* Write all the keys to a temporary buffer */
1795 buffer_put_bignum(&buf, sensitive_data.server_key->rsa->e);
1796 buffer_put_bignum(&buf, sensitive_data.server_key->rsa->n);
1799 buffer_put_bignum(&buf, sensitive_data.ssh1_host_key->rsa->e);
1800 buffer_put_bignum(&buf, sensitive_data.ssh1_host_key->rsa->n);
1802 /* Get the resulting data */
1803 data = (unsigned char *) buffer_ptr(&buf);
1804 data_len = buffer_len(&buf);
1807 MD5_Init(&md5context);
1808 MD5_Update(&md5context, data, data_len);
1809 MD5_Final(ssh1_key_digest, &md5context);
1817 /* Destroy the private and public keys. No longer. */
1818 destroy_sensitive_data();
1821 mm_ssh1_session_id(session_id);
1823 /* Destroy the decrypted integer. It is no longer needed. */
1824 BN_clear_free(session_key_int);
1826 /* Set the session key. From this on all communications will be encrypted. */
1827 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1829 /* Destroy our copy of the session key. It is no longer needed. */
1830 memset(session_key, 0, sizeof(session_key));
1832 debug("Received session key; encryption turned on.");
1834 /* Send an acknowledgment packet. Note that this packet is sent encrypted. */
1835 packet_start(SSH_SMSG_SUCCESS);
1837 packet_write_wait();
1841 * SSH2 key exchange: diffie-hellman-group1-sha1
1848 if (options.ciphers != NULL) {
1849 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1850 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
1852 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
1853 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
1854 myproposal[PROPOSAL_ENC_ALGS_STOC] =
1855 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
1857 if (options.macs != NULL) {
1858 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
1859 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
1861 if (!options.compression) {
1862 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
1863 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
1865 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
1871 char *newstr = NULL;
1872 orig = myproposal[PROPOSAL_KEX_ALGS];
1874 /* If we don't have a host key, then all of the algorithms
1875 * currently in myproposal are useless */
1876 if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])==0)
1879 if (options.gss_keyex)
1880 gss = ssh_gssapi_mechanisms(1,NULL);
1885 int len = strlen(orig) + strlen(gss) +2;
1886 newstr=xmalloc(len);
1887 snprintf(newstr,len,"%s,%s",gss,orig);
1893 /* If we've got GSSAPI mechanisms, then we've also got the 'null'
1894 host key algorithm, but we're not allowed to advertise it, unless
1895 its the only host key algorithm we're supporting */
1896 if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) {
1897 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]="null";
1900 myproposal[PROPOSAL_KEX_ALGS]=newstr;
1902 fatal("No supported key exchange algorithms");
1906 /* start key exchange */
1907 kex = kex_setup(myproposal);
1909 kex->client_version_string=client_version_string;
1910 kex->server_version_string=server_version_string;
1911 kex->load_host_key=&get_hostkey_by_type;
1912 kex->host_key_index=&get_hostkey_index;
1916 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
1918 session_id2 = kex->session_id;
1919 session_id2_len = kex->session_id_len;
1922 /* send 1st encrypted/maced/compressed message */
1923 packet_start(SSH2_MSG_IGNORE);
1924 packet_put_cstring("markus");
1926 packet_write_wait();