2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * Created: Fri Mar 17 17:09:28 1995 ylo
6 * This program is the ssh daemon. It listens for connections from clients, and
7 * performs authentication, executes use commands or shell, and forwards
8 * information to/from the application to the user client over an encrypted
9 * connection. This can also handle forwarding of X11, TCP/IP, and authentication
14 RCSID("$OpenBSD: sshd.c,v 1.94 2000/03/23 22:15:34 markus Exp $");
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_WARNING;
39 /* Local Xauthority file. */
40 static char *xauthfile = NULL;
42 /* Server configuration options. */
43 ServerOptions options;
45 /* Name of the server configuration file. */
46 char *config_file_name = SERVER_CONFIG_FILE;
49 * Flag indicating whether IPv4 or IPv6. This can be set on the command line.
50 * Default value is AF_UNSPEC means both IPv4 and IPv6.
53 int IPv4or6 = AF_INET;
55 int IPv4or6 = AF_UNSPEC;
59 * Debug mode flag. This can be set on the command line. If debug
60 * mode is enabled, extra debugging output will be sent to the system
61 * log, the daemon will not go to background, and will exit after processing
62 * the first connection.
66 /* Flag indicating that the daemon is being started from inetd. */
69 /* debug goes to stderr unless inetd_flag is set */
72 /* argv[0] without path. */
75 /* Saved arguments to main(). */
79 * The sockets that the server is listening; this is used in the SIGHUP
82 #define MAX_LISTEN_SOCKS 16
83 int listen_socks[MAX_LISTEN_SOCKS];
84 int num_listen_socks = 0;
87 * the client's version string, passed by sshd2 in compat mode. if != NULL,
88 * sshd will skip the version-number exchange
90 char *client_version_string = NULL;
92 /* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */
93 int no_port_forwarding_flag = 0;
94 int no_agent_forwarding_flag = 0;
95 int no_x11_forwarding_flag = 0;
98 /* RSA authentication "command=" option. */
99 char *forced_command = NULL;
101 /* RSA authentication "environment=" options. */
102 struct envstring *custom_environment = NULL;
104 /* Session id for the current session. */
105 unsigned char session_id[16];
108 * Any really sensitive data in the application is contained in this
109 * structure. The idea is that this structure could be locked into memory so
110 * that the pages do not get written into swap. However, there are some
111 * problems. The private key contains BIGNUMs, and we do not (in principle)
112 * have access to the internals of them, and locking just the structure is
113 * not very useful. Currently, memory locking is not implemented.
116 RSA *private_key; /* Private part of server key. */
117 RSA *host_key; /* Private part of host key. */
121 * Flag indicating whether the current session key has been used. This flag
122 * is set whenever the key is used, and cleared when the key is regenerated.
126 /* This is set to true when SIGHUP is received. */
127 int received_sighup = 0;
129 /* Public side of the server key. This value is regenerated regularly with
133 /* Prototypes for various functions defined later in this file. */
135 void do_authentication();
136 void do_authloop(struct passwd * pw);
137 void do_fake_authloop(char *user);
138 void do_authenticated(struct passwd * pw);
139 void do_exec_pty(const char *command, int ptyfd, int ttyfd,
140 const char *ttyname, struct passwd * pw, const char *term,
141 const char *display, const char *auth_proto,
142 const char *auth_data);
143 void do_exec_no_pty(const char *command, struct passwd * pw,
144 const char *display, const char *auth_proto,
145 const char *auth_data);
146 void do_child(const char *command, struct passwd * pw, const char *term,
147 const char *display, const char *auth_proto,
148 const char *auth_data, const char *ttyname);
151 * Remove local Xauthority file.
154 xauthfile_cleanup_proc(void *ignore)
156 debug("xauthfile_cleanup_proc called");
158 if (xauthfile != NULL) {
161 p = strrchr(xauthfile, '/');
172 * Close all listening sockets
175 close_listen_socks(void)
178 for (i = 0; i < num_listen_socks; i++)
179 close(listen_socks[i]);
180 num_listen_socks = -1;
184 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
185 * the effect is to reread the configuration file (and to regenerate
189 sighup_handler(int sig)
192 signal(SIGHUP, sighup_handler);
196 * Called from the main program after receiving SIGHUP.
197 * Restarts the server.
202 log("Received SIGHUP; restarting.");
203 close_listen_socks();
204 execv(saved_argv[0], saved_argv);
205 log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno));
210 * Generic signal handler for terminating signals in the master daemon.
211 * These close the listen socket; not closing it seems to cause "Address
212 * already in use" problems on some machines, which is inconvenient.
215 sigterm_handler(int sig)
217 log("Received signal %d; terminating.", sig);
218 close_listen_socks();
223 * SIGCHLD handler. This is called whenever a child dies. This will then
224 * reap any zombies left by exited c.
227 main_sigchld_handler(int sig)
229 int save_errno = errno;
232 while (waitpid(-1, &status, WNOHANG) > 0)
235 signal(SIGCHLD, main_sigchld_handler);
240 * Signal handler for the alarm after the login grace period has expired.
243 grace_alarm_handler(int sig)
245 /* Close the connection. */
248 /* Log error and exit. */
249 fatal("Timeout before authentication for %s.", get_remote_ipaddr());
253 * convert ssh auth msg type into description
256 get_authname(int type)
258 static char buf[1024];
260 case SSH_CMSG_AUTH_PASSWORD:
262 case SSH_CMSG_AUTH_RSA:
264 case SSH_CMSG_AUTH_RHOSTS_RSA:
266 case SSH_CMSG_AUTH_RHOSTS:
269 case SSH_CMSG_AUTH_KERBEROS:
273 case SSH_CMSG_AUTH_TIS_RESPONSE:
277 snprintf(buf, sizeof buf, "bad-auth-msg-%d", type);
282 * Signal handler for the key regeneration alarm. Note that this
283 * alarm only occurs in the daemon waiting for connections, and it does not
284 * do anything with the private key or random state before forking.
285 * Thus there should be no concurrency control/asynchronous execution
289 key_regeneration_alarm(int sig)
291 int save_errno = errno;
293 /* Check if we should generate a new key. */
295 /* This should really be done in the background. */
296 log("Generating new %d bit RSA key.", options.server_key_bits);
298 if (sensitive_data.private_key != NULL)
299 RSA_free(sensitive_data.private_key);
300 sensitive_data.private_key = RSA_new();
302 if (public_key != NULL)
303 RSA_free(public_key);
304 public_key = RSA_new();
306 rsa_generate_key(sensitive_data.private_key, public_key,
307 options.server_key_bits);
310 log("RSA key generation complete.");
312 /* Reschedule the alarm. */
313 signal(SIGALRM, key_regeneration_alarm);
314 alarm(options.key_regeneration_time);
319 * Main program for the daemon.
322 main(int ac, char **av)
326 int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1;
328 int remote_major, remote_minor;
331 struct sockaddr_storage from;
332 char buf[100]; /* Must not be larger than remote_version. */
333 char remote_version[100]; /* Must be at least as big as buf. */
334 const char *remote_ip;
338 struct linger linger;
340 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
341 int listen_sock, maxfd;
345 if (strchr(av[0], '/'))
346 av0 = strrchr(av[0], '/') + 1;
350 /* Initialize configuration options to their default values. */
351 initialize_server_options(&options);
353 /* Parse command-line arguments. */
354 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ46")) != EOF) {
363 config_file_name = optarg;
367 options.log_level = SYSLOG_LEVEL_DEBUG;
376 options.log_level = SYSLOG_LEVEL_QUIET;
379 options.server_key_bits = atoi(optarg);
382 options.ports_from_cmdline = 1;
383 if (options.num_ports >= MAX_PORTS)
384 fatal("too many ports.\n");
385 options.ports[options.num_ports++] = atoi(optarg);
388 options.login_grace_time = atoi(optarg);
391 options.key_regeneration_time = atoi(optarg);
394 options.host_key_file = optarg;
397 client_version_string = optarg;
398 /* only makes sense with inetd_flag, i.e. no listen() */
403 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
404 fprintf(stderr, "Usage: %s [options]\n", av0);
405 fprintf(stderr, "Options:\n");
406 fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE);
407 fprintf(stderr, " -d Debugging mode\n");
408 fprintf(stderr, " -i Started from inetd\n");
409 fprintf(stderr, " -q Quiet (no logging)\n");
410 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
411 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
412 fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n");
413 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
414 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
416 fprintf(stderr, " -4 Use IPv4 only\n");
417 fprintf(stderr, " -6 Use IPv6 only\n");
423 * Force logging to stderr until we have loaded the private host
424 * key (unless started from inetd)
427 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
428 options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
431 /* check if RSA support exists */
432 if (rsa_alive() == 0) {
434 printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n");
435 log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)");
438 /* Read server configuration options from the configuration file. */
439 read_server_config(&options, config_file_name);
441 /* Fill in default values for those options not explicitly set. */
442 fill_default_server_options(&options);
444 /* Check certain values for sanity. */
445 if (options.server_key_bits < 512 ||
446 options.server_key_bits > 32768) {
447 fprintf(stderr, "Bad server key size.\n");
450 /* Check that there are no remaining arguments. */
452 fprintf(stderr, "Extra argument %s.\n", av[optind]);
456 debug("sshd version %.100s", SSH_VERSION);
458 sensitive_data.host_key = RSA_new();
460 /* Load the host key. It must have empty passphrase. */
461 if (!load_private_key(options.host_key_file, "",
462 sensitive_data.host_key, &comment)) {
463 error("Could not load host key: %.200s: %.100s",
464 options.host_key_file, strerror(errno));
469 /* Initialize the log (it is reinitialized below in case we
471 if (debug_flag && !inetd_flag)
473 log_init(av0, options.log_level, options.log_facility, log_stderr);
475 /* If not in debugging mode, and not started from inetd,
476 disconnect from the controlling terminal, and fork. The
477 original process exits. */
478 if (!debug_flag && !inetd_flag) {
481 #endif /* TIOCNOTTY */
482 if (daemon(0, 0) < 0)
483 fatal("daemon() failed: %.200s", strerror(errno));
485 /* Disconnect from the controlling tty. */
487 fd = open("/dev/tty", O_RDWR | O_NOCTTY);
489 (void) ioctl(fd, TIOCNOTTY, NULL);
492 #endif /* TIOCNOTTY */
494 /* Reinitialize the log (because of the fork above). */
495 log_init(av0, options.log_level, options.log_facility, log_stderr);
497 /* Check that server and host key lengths differ sufficiently.
498 This is necessary to make double encryption work with rsaref.
499 Oh, I hate software patents. I dont know if this can go? Niels */
500 if (options.server_key_bits >
501 BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
502 options.server_key_bits <
503 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
504 options.server_key_bits =
505 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
506 debug("Forcing server key to %d bits to make it differ from host key.",
507 options.server_key_bits);
509 /* Do not display messages to stdout in RSA code. */
512 /* Initialize the random number generator. */
515 /* Chdir to the root directory so that the current disk can be
516 unmounted if desired. */
519 /* Start listening for a socket, unless started from inetd. */
522 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
526 /* We intentionally do not close the descriptors 0, 1, and 2
527 as our code for setting the descriptors won\'t work
528 if ttyfd happens to be one of those. */
529 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
531 public_key = RSA_new();
532 sensitive_data.private_key = RSA_new();
534 log("Generating %d bit RSA key.", options.server_key_bits);
535 rsa_generate_key(sensitive_data.private_key, public_key,
536 options.server_key_bits);
538 log("RSA key generation complete.");
540 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
541 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
543 if (num_listen_socks >= MAX_LISTEN_SOCKS)
544 fatal("Too many listen sockets. "
545 "Enlarge MAX_LISTEN_SOCKS");
546 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
547 ntop, sizeof(ntop), strport, sizeof(strport),
548 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
549 error("getnameinfo failed");
552 /* Create socket for listening. */
553 listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
554 if (listen_sock < 0) {
555 /* kernel may not support ipv6 */
556 verbose("socket: %.100s", strerror(errno));
559 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
560 error("listen_sock O_NONBLOCK: %s", strerror(errno));
565 * Set socket options. We try to make the port
566 * reusable and have it close as fast as possible
567 * without waiting in unnecessary wait states on
570 setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
571 (void *) &on, sizeof(on));
574 setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
575 (void *) &linger, sizeof(linger));
577 debug("Bind to port %s on %s.", strport, ntop);
579 /* Bind the socket to the desired port. */
580 if ((bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) &&
582 error("Bind to port %s on %s failed: %.200s.",
583 strport, ntop, strerror(errno));
587 listen_socks[num_listen_socks] = listen_sock;
590 /* Start listening on the port. */
591 log("Server listening on %s port %s.", ntop, strport);
592 if (listen(listen_sock, 5) < 0)
593 fatal("listen: %.100s", strerror(errno));
596 freeaddrinfo(options.listen_addrs);
598 if (!num_listen_socks)
599 fatal("Cannot bind any address.");
603 * Record our pid in /etc/sshd_pid to make it easier
604 * to kill the correct sshd. We don\'t want to do
605 * this before the bind above because the bind will
606 * fail if there already is a daemon, and this will
607 * overwrite any old pid in the file.
609 f = fopen(SSH_DAEMON_PID_FILE, "w");
611 fprintf(f, "%u\n", (unsigned int) getpid());
616 public_key = RSA_new();
617 sensitive_data.private_key = RSA_new();
619 log("Generating %d bit RSA key.", options.server_key_bits);
620 rsa_generate_key(sensitive_data.private_key, public_key,
621 options.server_key_bits);
623 log("RSA key generation complete.");
625 /* Schedule server key regeneration alarm. */
626 signal(SIGALRM, key_regeneration_alarm);
627 alarm(options.key_regeneration_time);
629 /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
630 signal(SIGHUP, sighup_handler);
631 signal(SIGTERM, sigterm_handler);
632 signal(SIGQUIT, sigterm_handler);
634 /* Arrange SIGCHLD to be caught. */
635 signal(SIGCHLD, main_sigchld_handler);
637 /* setup fd set for listen */
639 for (i = 0; i < num_listen_socks; i++)
640 if (listen_socks[i] > maxfd)
641 maxfd = listen_socks[i];
642 fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
643 fdset = (fd_set *)xmalloc(fdsetsz);
646 * Stay listening for connections until the system crashes or
647 * the daemon is killed with a signal.
652 /* Wait in select until there is a connection. */
653 memset(fdset, 0, fdsetsz);
654 for (i = 0; i < num_listen_socks; i++)
655 FD_SET(listen_socks[i], fdset);
656 if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) {
658 error("select: %.100s", strerror(errno));
661 for (i = 0; i < num_listen_socks; i++) {
662 if (!FD_ISSET(listen_socks[i], fdset))
664 fromlen = sizeof(from);
665 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
668 if (errno != EINTR && errno != EWOULDBLOCK)
669 error("accept: %.100s", strerror(errno));
672 if (fcntl(newsock, F_SETFL, 0) < 0) {
673 error("newsock del O_NONBLOCK: %s", strerror(errno));
677 * Got connection. Fork a child to handle it, unless
678 * we are in debugging mode.
682 * In debugging mode. Close the listening
683 * socket, and start processing the
684 * connection without forking.
686 debug("Server will not fork when running in debugging mode.");
687 close_listen_socks();
694 * Normal production daemon. Fork, and have
695 * the child process the connection. The
696 * parent continues listening.
698 if ((pid = fork()) == 0) {
700 * Child. Close the listening socket, and start using the
701 * accepted socket. Reinitialize logging (since our pid has
702 * changed). We break out of the loop to handle the connection.
704 close_listen_socks();
707 log_init(av0, options.log_level, options.log_facility, log_stderr);
712 /* Parent. Stay in the loop. */
714 error("fork: %.100s", strerror(errno));
716 debug("Forked child %d.", pid);
718 /* Mark that the key has been used (it was "given" to the child). */
723 /* Close the new socket (the child is now taking care of it). */
725 } /* for (i = 0; i < num_listen_socks; i++) */
726 /* child process check (or debug mode) */
727 if (num_listen_socks < 0)
732 /* This is the child processing a new connection. */
735 * Disable the key regeneration alarm. We will not regenerate the
736 * key since we are no longer in a position to give it to anyone. We
737 * will not restart on SIGHUP since it no longer makes sense.
740 signal(SIGALRM, SIG_DFL);
741 signal(SIGHUP, SIG_DFL);
742 signal(SIGTERM, SIG_DFL);
743 signal(SIGQUIT, SIG_DFL);
744 signal(SIGCHLD, SIG_DFL);
747 * Set socket options for the connection. We want the socket to
748 * close as fast as possible without waiting for anything. If the
749 * connection is not a socket, these will do nothing.
751 /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
754 setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
757 * Register our connection. This turns encryption off because we do
760 packet_set_connection(sock_in, sock_out);
762 remote_port = get_remote_port();
763 remote_ip = get_remote_ipaddr();
765 /* Check whether logins are denied from this host. */
767 /* XXX LIBWRAP noes not know about IPv6 */
769 struct request_info req;
771 request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL);
774 if (!hosts_access(&req)) {
779 /*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
782 /* Log the connection. */
783 verbose("Connection from %.500s port %d", remote_ip, remote_port);
786 * We don\'t want to listen forever unless the other side
787 * successfully authenticates itself. So we set up an alarm which is
788 * cleared after successful authentication. A limit of zero
789 * indicates no limit. Note that we don\'t set the alarm in debugging
790 * mode; it is just annoying to have the server exit just when you
791 * are about to discover the bug.
793 signal(SIGALRM, grace_alarm_handler);
795 alarm(options.login_grace_time);
797 if (client_version_string != NULL) {
798 /* we are exec'ed by sshd2, so skip exchange of protocol version */
799 strlcpy(buf, client_version_string, sizeof(buf));
801 /* Send our protocol version identification. */
802 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
803 PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
804 if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) {
805 log("Could not write ident string to %s.", remote_ip);
809 /* Read other side\'s version identification. */
810 for (i = 0; i < sizeof(buf) - 1; i++) {
811 if (read(sock_in, &buf[i], 1) != 1) {
812 log("Did not receive ident string from %s.", remote_ip);
815 if (buf[i] == '\r') {
820 if (buf[i] == '\n') {
826 buf[sizeof(buf) - 1] = 0;
830 * Check that the versions match. In future this might accept
831 * several versions and set appropriate flags to handle them.
833 if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor,
834 remote_version) != 3) {
835 char *s = "Protocol mismatch.\n";
837 (void) atomicio(write, sock_out, s, strlen(s));
840 log("Bad protocol version identification '%.100s' from %s",
844 debug("Client protocol version %d.%d; client software version %.100s",
845 remote_major, remote_minor, remote_version);
846 if (remote_major != PROTOCOL_MAJOR) {
847 char *s = "Protocol major versions differ.\n";
849 (void) atomicio(write, sock_out, s, strlen(s));
852 log("Protocol major versions differ for %s: %d vs. %d",
853 remote_ip, PROTOCOL_MAJOR, remote_major);
856 /* Check that the client has sufficiently high software version. */
857 if (remote_major == 1 && remote_minor < 3)
858 packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version.");
860 if (remote_major == 1 && remote_minor == 3) {
861 /* note that this disables agent-forwarding */
865 * Check that the connection comes from a privileged port. Rhosts-
866 * and Rhosts-RSA-Authentication only make sense from priviledged
867 * programs. Of course, if the intruder has root access on his local
868 * machine, he can connect from any port. So do not use these
869 * authentication methods from machines that you do not trust.
871 if (remote_port >= IPPORT_RESERVED ||
872 remote_port < IPPORT_RESERVED / 2) {
873 options.rhosts_authentication = 0;
874 options.rhosts_rsa_authentication = 0;
877 if (!packet_connection_is_ipv4() &&
878 options.kerberos_authentication) {
879 debug("Kerberos Authentication disabled, only available for IPv4.");
880 options.kerberos_authentication = 0;
884 packet_set_nonblocking();
886 /* perform the key exchange */
889 /* authenticate user and start session */
893 /* Cleanup user's ticket cache file. */
894 if (options.kerberos_ticket_cleanup)
898 /* Cleanup user's local Xauthority file. */
900 xauthfile_cleanup_proc(NULL);
902 /* The connection has been terminated. */
903 verbose("Closing connection to %.100s", remote_ip);
921 BIGNUM *session_key_int;
922 unsigned char session_key[SSH_SESSION_KEY_LENGTH];
923 unsigned char cookie[8];
924 unsigned int cipher_type, auth_mask, protocol_flags;
928 * Generate check bytes that the client must send back in the user
929 * packet in order for it to be accepted; this is used to defy ip
930 * spoofing attacks. Note that this only works against somebody
931 * doing IP spoofing from a remote machine; any machine on the local
932 * network can still see outgoing packets and catch the random
933 * cookie. This only affects rhosts authentication, and this is one
934 * of the reasons why it is inherently insecure.
936 for (i = 0; i < 8; i++) {
939 cookie[i] = rand & 0xff;
944 * Send our public key. We include in the packet 64 bits of random
945 * data that must be matched in the reply in order to prevent IP
948 packet_start(SSH_SMSG_PUBLIC_KEY);
949 for (i = 0; i < 8; i++)
950 packet_put_char(cookie[i]);
952 /* Store our public server RSA key. */
953 packet_put_int(BN_num_bits(public_key->n));
954 packet_put_bignum(public_key->e);
955 packet_put_bignum(public_key->n);
957 /* Store our public host RSA key. */
958 packet_put_int(BN_num_bits(sensitive_data.host_key->n));
959 packet_put_bignum(sensitive_data.host_key->e);
960 packet_put_bignum(sensitive_data.host_key->n);
962 /* Put protocol flags. */
963 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
965 /* Declare which ciphers we support. */
966 packet_put_int(cipher_mask());
968 /* Declare supported authentication types. */
970 if (options.rhosts_authentication)
971 auth_mask |= 1 << SSH_AUTH_RHOSTS;
972 if (options.rhosts_rsa_authentication)
973 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
974 if (options.rsa_authentication)
975 auth_mask |= 1 << SSH_AUTH_RSA;
977 if (options.kerberos_authentication)
978 auth_mask |= 1 << SSH_AUTH_KERBEROS;
981 if (options.kerberos_tgt_passing)
982 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
983 if (options.afs_token_passing)
984 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
987 if (options.skey_authentication == 1)
988 auth_mask |= 1 << SSH_AUTH_TIS;
990 if (options.password_authentication)
991 auth_mask |= 1 << SSH_AUTH_PASSWORD;
992 packet_put_int(auth_mask);
994 /* Send the packet and wait for it to be sent. */
998 debug("Sent %d bit public key and %d bit host key.",
999 BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n));
1001 /* Read clients reply (cipher type and session key). */
1002 packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
1004 /* Get cipher type and check whether we accept this. */
1005 cipher_type = packet_get_char();
1007 if (!(cipher_mask() & (1 << cipher_type)))
1008 packet_disconnect("Warning: client selects unsupported cipher.");
1010 /* Get check bytes from the packet. These must match those we
1011 sent earlier with the public key packet. */
1012 for (i = 0; i < 8; i++)
1013 if (cookie[i] != packet_get_char())
1014 packet_disconnect("IP Spoofing check bytes do not match.");
1016 debug("Encryption type: %.200s", cipher_name(cipher_type));
1018 /* Get the encrypted integer. */
1019 session_key_int = BN_new();
1020 packet_get_bignum(session_key_int, &slen);
1022 protocol_flags = packet_get_int();
1023 packet_set_protocol_flags(protocol_flags);
1025 packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
1028 * Decrypt it using our private server key and private host key (key
1029 * with larger modulus first).
1031 if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) {
1032 /* Private key has bigger modulus. */
1033 if (BN_num_bits(sensitive_data.private_key->n) <
1034 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
1035 fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1036 get_remote_ipaddr(),
1037 BN_num_bits(sensitive_data.private_key->n),
1038 BN_num_bits(sensitive_data.host_key->n),
1039 SSH_KEY_BITS_RESERVED);
1041 rsa_private_decrypt(session_key_int, session_key_int,
1042 sensitive_data.private_key);
1043 rsa_private_decrypt(session_key_int, session_key_int,
1044 sensitive_data.host_key);
1046 /* Host key has bigger modulus (or they are equal). */
1047 if (BN_num_bits(sensitive_data.host_key->n) <
1048 BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) {
1049 fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d",
1050 get_remote_ipaddr(),
1051 BN_num_bits(sensitive_data.host_key->n),
1052 BN_num_bits(sensitive_data.private_key->n),
1053 SSH_KEY_BITS_RESERVED);
1055 rsa_private_decrypt(session_key_int, session_key_int,
1056 sensitive_data.host_key);
1057 rsa_private_decrypt(session_key_int, session_key_int,
1058 sensitive_data.private_key);
1061 compute_session_id(session_id, cookie,
1062 sensitive_data.host_key->n,
1063 sensitive_data.private_key->n);
1065 /* Destroy the private and public keys. They will no longer be needed. */
1066 RSA_free(public_key);
1067 RSA_free(sensitive_data.private_key);
1068 RSA_free(sensitive_data.host_key);
1071 * Extract session key from the decrypted integer. The key is in the
1072 * least significant 256 bits of the integer; the first byte of the
1073 * key is in the highest bits.
1075 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1076 len = BN_num_bytes(session_key_int);
1077 if (len < 0 || len > sizeof(session_key))
1078 fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d",
1079 get_remote_ipaddr(),
1080 len, sizeof(session_key));
1081 memset(session_key, 0, sizeof(session_key));
1082 BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
1084 /* Destroy the decrypted integer. It is no longer needed. */
1085 BN_clear_free(session_key_int);
1087 /* Xor the first 16 bytes of the session key with the session id. */
1088 for (i = 0; i < 16; i++)
1089 session_key[i] ^= session_id[i];
1091 /* Set the session key. From this on all communications will be encrypted. */
1092 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1094 /* Destroy our copy of the session key. It is no longer needed. */
1095 memset(session_key, 0, sizeof(session_key));
1097 debug("Received session key; encryption turned on.");
1099 /* Send an acknowledgement packet. Note that this packet is sent encrypted. */
1100 packet_start(SSH_SMSG_SUCCESS);
1102 packet_write_wait();
1107 * Check if the user is allowed to log in via ssh. If user is listed in
1108 * DenyUsers or user's primary group is listed in DenyGroups, false will
1109 * be returned. If AllowUsers isn't empty and user isn't listed there, or
1110 * if AllowGroups isn't empty and user isn't listed there, false will be
1112 * If the user's shell is not executable, false will be returned.
1113 * Otherwise true is returned.
1116 allowed_user(struct passwd * pw)
1121 #ifdef WITH_AIXAUTHENTICATE
1123 #endif /* WITH_AIXAUTHENTICATE */
1125 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
1129 /* deny if shell does not exists or is not executable */
1130 if (stat(pw->pw_shell, &st) != 0)
1132 if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP))))
1135 /* Return false if user is listed in DenyUsers */
1136 if (options.num_deny_users > 0) {
1139 for (i = 0; i < options.num_deny_users; i++)
1140 if (match_pattern(pw->pw_name, options.deny_users[i]))
1143 /* Return false if AllowUsers isn't empty and user isn't listed there */
1144 if (options.num_allow_users > 0) {
1147 for (i = 0; i < options.num_allow_users; i++)
1148 if (match_pattern(pw->pw_name, options.allow_users[i]))
1150 /* i < options.num_allow_users iff we break for loop */
1151 if (i >= options.num_allow_users)
1154 /* Get the primary group name if we need it. Return false if it fails */
1155 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
1156 grp = getgrgid(pw->pw_gid);
1160 /* Return false if user's group is listed in DenyGroups */
1161 if (options.num_deny_groups > 0) {
1164 for (i = 0; i < options.num_deny_groups; i++)
1165 if (match_pattern(grp->gr_name, options.deny_groups[i]))
1169 * Return false if AllowGroups isn't empty and user's group
1170 * isn't listed there
1172 if (options.num_allow_groups > 0) {
1175 for (i = 0; i < options.num_allow_groups; i++)
1176 if (match_pattern(grp->gr_name, options.allow_groups[i]))
1178 /* i < options.num_allow_groups iff we break for
1180 if (i >= options.num_allow_groups)
1185 #ifdef WITH_AIXAUTHENTICATE
1186 if (loginrestrictions(pw->pw_name,S_LOGIN,NULL,&loginmsg) != 0)
1188 #endif /* WITH_AIXAUTHENTICATE */
1190 /* We found no reason not to let this user try to log on... */
1195 * Performs authentication of an incoming connection. Session key has already
1196 * been exchanged and encryption is enabled.
1201 struct passwd *pw, pwcopy;
1206 /* Get the name of the user that we wish to log in as. */
1207 packet_read_expect(&plen, SSH_CMSG_USER);
1209 /* Get the user name. */
1210 user = packet_get_string(&ulen);
1211 packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
1213 setproctitle("%s", user);
1215 #ifdef WITH_AIXAUTHENTICATE
1217 #endif /* WITH_AIXAUTHENTICATE */
1220 /* If machine has AFS, set process authentication group. */
1227 /* Verify that the user is a valid user. */
1228 pw = getpwnam(user);
1229 if (!pw || !allowed_user(pw))
1230 do_fake_authloop(user);
1233 /* Take a copy of the returned structure. */
1234 memset(&pwcopy, 0, sizeof(pwcopy));
1235 pwcopy.pw_name = xstrdup(pw->pw_name);
1236 pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
1237 pwcopy.pw_uid = pw->pw_uid;
1238 pwcopy.pw_gid = pw->pw_gid;
1239 pwcopy.pw_dir = xstrdup(pw->pw_dir);
1240 pwcopy.pw_shell = xstrdup(pw->pw_shell);
1248 * If we are not running as root, the user must have the same uid as
1251 if (getuid() != 0 && pw->pw_uid != getuid())
1252 packet_disconnect("Cannot change user when server not running as root.");
1254 debug("Attempting authentication for %.100s.", pw->pw_name);
1256 /* If the user has no password, accept authentication immediately. */
1257 if (options.password_authentication &&
1259 (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
1262 auth_pam_password(pw, "")) {
1264 auth_password(pw, "")) {
1265 #endif /* USE_PAM */
1266 /* Authentication with empty password succeeded. */
1267 log("Login for user %s from %.100s, accepted without authentication.",
1268 pw->pw_name, get_remote_ipaddr());
1270 /* Loop until the user has been authenticated or the
1271 connection is closed, do_authloop() returns only if
1272 authentication is successfull */
1276 /* The user has been authenticated and accepted. */
1277 #ifdef WITH_AIXAUTHENTICATE
1278 loginsuccess(user,get_canonical_hostname(),"ssh",&loginmsg);
1279 #endif /* WITH_AIXAUTHENTICATE */
1280 packet_start(SSH_SMSG_SUCCESS);
1282 packet_write_wait();
1284 /* Perform session preparation. */
1285 do_authenticated(pw);
1288 #define AUTH_FAIL_MAX 6
1289 #define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2)
1290 #define AUTH_FAIL_MSG "Too many authentication failures for %.100s"
1293 * read packets and try to authenticate local user *pw.
1294 * return if authentication is successfull
1297 do_authloop(struct passwd * pw)
1301 RSA *client_host_key;
1303 char *client_user = NULL, *password = NULL;
1306 int plen, nlen, elen;
1309 void (*authlog) (const char *fmt,...) = verbose;
1311 /* Indicate that authentication is needed. */
1312 packet_start(SSH_SMSG_FAILURE);
1314 packet_write_wait();
1316 for (attempt = 1;; attempt++) {
1317 int authenticated = 0;
1318 strlcpy(user, "", sizeof user);
1320 /* Get a packet from the client. */
1321 type = packet_read(&plen);
1323 /* Process the packet. */
1326 case SSH_CMSG_HAVE_KERBEROS_TGT:
1327 if (!options.kerberos_tgt_passing) {
1328 /* packet_get_all(); */
1329 verbose("Kerberos tgt passing disabled.");
1332 /* Accept Kerberos tgt. */
1333 char *tgt = packet_get_string(&dlen);
1334 packet_integrity_check(plen, 4 + dlen, type);
1335 if (!auth_kerberos_tgt(pw, tgt))
1336 verbose("Kerberos tgt REFUSED for %s", pw->pw_name);
1341 case SSH_CMSG_HAVE_AFS_TOKEN:
1342 if (!options.afs_token_passing || !k_hasafs()) {
1343 /* packet_get_all(); */
1344 verbose("AFS token passing disabled.");
1347 /* Accept AFS token. */
1348 char *token_string = packet_get_string(&dlen);
1349 packet_integrity_check(plen, 4 + dlen, type);
1350 if (!auth_afs_token(pw, token_string))
1351 verbose("AFS token REFUSED for %s", pw->pw_name);
1352 xfree(token_string);
1357 case SSH_CMSG_AUTH_KERBEROS:
1358 if (!options.kerberos_authentication) {
1359 /* packet_get_all(); */
1360 verbose("Kerberos authentication disabled.");
1363 /* Try Kerberos v4 authentication. */
1365 char *tkt_user = NULL;
1366 char *kdata = packet_get_string((unsigned int *) &auth.length);
1367 packet_integrity_check(plen, 4 + auth.length, type);
1369 if (auth.length < MAX_KTXT_LEN)
1370 memcpy(auth.dat, kdata, auth.length);
1373 authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
1375 if (authenticated) {
1376 snprintf(user, sizeof user, " tktuser %s", tkt_user);
1383 case SSH_CMSG_AUTH_RHOSTS:
1384 if (!options.rhosts_authentication) {
1385 verbose("Rhosts authentication disabled.");
1389 * Get client user name. Note that we just have to
1390 * trust the client; this is one reason why rhosts
1391 * authentication is insecure. (Another is
1392 * IP-spoofing on a local network.)
1394 client_user = packet_get_string(&ulen);
1395 packet_integrity_check(plen, 4 + ulen, type);
1397 /* Try to authenticate using /etc/hosts.equiv and
1399 authenticated = auth_rhosts(pw, client_user);
1401 snprintf(user, sizeof user, " ruser %s", client_user);
1404 case SSH_CMSG_AUTH_RHOSTS_RSA:
1405 if (!options.rhosts_rsa_authentication) {
1406 verbose("Rhosts with RSA authentication disabled.");
1410 * Get client user name. Note that we just have to
1411 * trust the client; root on the client machine can
1412 * claim to be any user.
1414 client_user = packet_get_string(&ulen);
1416 /* Get the client host key. */
1417 client_host_key = RSA_new();
1418 if (client_host_key == NULL)
1419 fatal("RSA_new failed");
1420 client_host_key->e = BN_new();
1421 client_host_key->n = BN_new();
1422 if (client_host_key->e == NULL || client_host_key->n == NULL)
1423 fatal("BN_new failed");
1424 bits = packet_get_int();
1425 packet_get_bignum(client_host_key->e, &elen);
1426 packet_get_bignum(client_host_key->n, &nlen);
1428 if (bits != BN_num_bits(client_host_key->n))
1429 error("Warning: keysize mismatch for client_host_key: "
1430 "actual %d, announced %d", BN_num_bits(client_host_key->n), bits);
1431 packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
1433 authenticated = auth_rhosts_rsa(pw, client_user, client_host_key);
1434 RSA_free(client_host_key);
1436 snprintf(user, sizeof user, " ruser %s", client_user);
1439 case SSH_CMSG_AUTH_RSA:
1440 if (!options.rsa_authentication) {
1441 verbose("RSA authentication disabled.");
1444 /* RSA authentication requested. */
1446 packet_get_bignum(n, &nlen);
1447 packet_integrity_check(plen, nlen, type);
1448 authenticated = auth_rsa(pw, n);
1452 case SSH_CMSG_AUTH_PASSWORD:
1453 if (!options.password_authentication) {
1454 verbose("Password authentication disabled.");
1458 * Read user password. It is in plain text, but was
1459 * transmitted over the encrypted channel so it is
1460 * not visible to an outside observer.
1462 password = packet_get_string(&dlen);
1463 packet_integrity_check(plen, 4 + dlen, type);
1466 /* Do PAM auth with password */
1467 authenticated = auth_pam_password(pw, password);
1469 /* Try authentication with the password. */
1470 authenticated = auth_password(pw, password);
1471 #endif /* USE_PAM */
1472 memset(password, 0, strlen(password));
1477 case SSH_CMSG_AUTH_TIS:
1478 debug("rcvd SSH_CMSG_AUTH_TIS");
1479 if (options.skey_authentication == 1) {
1480 char *skeyinfo = skey_keyinfo(pw->pw_name);
1481 if (skeyinfo == NULL) {
1482 debug("generating fake skeyinfo for %.100s.", pw->pw_name);
1483 skeyinfo = skey_fake_keyinfo(pw->pw_name);
1485 if (skeyinfo != NULL) {
1486 /* we send our s/key- in tis-challenge messages */
1487 debug("sending challenge '%s'", skeyinfo);
1488 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1489 packet_put_string(skeyinfo, strlen(skeyinfo));
1491 packet_write_wait();
1496 case SSH_CMSG_AUTH_TIS_RESPONSE:
1497 debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
1498 if (options.skey_authentication == 1) {
1499 char *response = packet_get_string(&dlen);
1500 debug("skey response == '%s'", response);
1501 packet_integrity_check(plen, 4 + dlen, type);
1502 authenticated = (skey_haskey(pw->pw_name) == 0 &&
1503 skey_passcheck(pw->pw_name, response) != -1);
1508 case SSH_CMSG_AUTH_TIS:
1509 /* TIS Authentication is unsupported */
1510 log("TIS authentication unsupported.");
1516 * Any unknown messages will be ignored (and failure
1517 * returned) during authentication.
1519 log("Unknown message during authentication: type %d", type);
1524 * Check if the user is logging in as root and root logins
1526 * Note that root login is allowed for forced commands.
1528 if (authenticated && pw->pw_uid == 0 && !options.permit_root_login) {
1529 if (forced_command) {
1530 log("Root login accepted for forced command.");
1533 log("ROOT LOGIN REFUSED FROM %.200s",
1534 get_canonical_hostname());
1538 /* Raise logging level */
1539 if (authenticated ||
1540 attempt == AUTH_FAIL_LOG ||
1541 type == SSH_CMSG_AUTH_PASSWORD)
1544 authlog("%s %s for %.200s from %.200s port %d%s",
1545 authenticated ? "Accepted" : "Failed",
1547 pw->pw_uid == 0 ? "ROOT" : pw->pw_name,
1548 get_remote_ipaddr(),
1553 if (authenticated) {
1554 if (!do_pam_account(pw->pw_name, client_user)) {
1555 if (client_user != NULL) {
1559 do_fake_authloop(pw->pw_name);
1564 if (authenticated) {
1567 #endif /* USE_PAM */
1569 if (client_user != NULL) {
1574 if (attempt > AUTH_FAIL_MAX)
1575 packet_disconnect(AUTH_FAIL_MSG, pw->pw_name);
1577 /* Send a message indicating that the authentication attempt failed. */
1578 packet_start(SSH_SMSG_FAILURE);
1580 packet_write_wait();
1585 * The user does not exist or access is denied,
1586 * but fake indication that authentication is needed.
1589 do_fake_authloop(char *user)
1593 log("Faking authloop for illegal user %.200s from %.200s port %d",
1595 get_remote_ipaddr(),
1598 /* Indicate that authentication is needed. */
1599 packet_start(SSH_SMSG_FAILURE);
1601 packet_write_wait();
1604 * Keep reading packets, and always respond with a failure. This is
1605 * to avoid disclosing whether such a user really exists.
1607 for (attempt = 1;; attempt++) {
1608 /* Read a packet. This will not return if the client disconnects. */
1611 (void)packet_read(&plen);
1613 int type = packet_read(&plen);
1615 char *password, *skeyinfo;
1616 /* Try to send a fake s/key challenge. */
1617 if (options.skey_authentication == 1 &&
1618 (skeyinfo = skey_fake_keyinfo(user)) != NULL) {
1620 if (type == SSH_CMSG_AUTH_TIS) {
1621 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1622 packet_put_string(skeyinfo, strlen(skeyinfo));
1624 packet_write_wait();
1626 } else if (type == SSH_CMSG_AUTH_PASSWORD &&
1627 options.password_authentication &&
1628 (password = packet_get_string(&dlen)) != NULL &&
1630 strncasecmp(password, "s/key", 5) == 0 ) {
1631 packet_send_debug(skeyinfo);
1633 if (password != NULL)
1637 if (attempt > AUTH_FAIL_MAX)
1638 packet_disconnect(AUTH_FAIL_MSG, user);
1641 * Send failure. This should be indistinguishable from a
1642 * failed authentication.
1644 packet_start(SSH_SMSG_FAILURE);
1646 packet_write_wait();
1647 #ifdef WITH_AIXAUTHENTICATE
1648 if (strncmp(get_authname(type),"password",
1649 strlen(get_authname(type))) == 0)
1650 loginfailed(pw->pw_name,get_canonical_hostname(),"ssh");
1651 #endif /* WITH_AIXAUTHENTICATE */
1657 struct pty_cleanup_context {
1658 const char *ttyname;
1663 * Function to perform cleanup if we get aborted abnormally (e.g., due to a
1664 * dropped connection).
1667 pty_cleanup_proc(void *context)
1669 struct pty_cleanup_context *cu = context;
1671 debug("pty_cleanup_proc called");
1673 /* Record that the user has logged out. */
1674 record_logout(cu->pid, cu->ttyname);
1676 /* Release the pseudo-tty. */
1677 pty_release(cu->ttyname);
1680 /* simple cleanup: chown tty slave back to root */
1682 pty_release_proc(void *tty)
1684 char *ttyname = tty;
1685 pty_release(ttyname);
1689 * Prepares for an interactive session. This is called after the user has
1690 * been successfully authenticated. During this message exchange, pseudo
1691 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
1692 * are requested, etc.
1695 do_authenticated(struct passwd * pw)
1698 int compression_level = 0, enable_compression_after_reply = 0;
1699 int have_pty = 0, ptyfd = -1, ttyfd = -1;
1700 int row, col, xpixel, ypixel, screen;
1702 char *command, *term = NULL, *display = NULL, *proto = NULL, *data = NULL;
1708 * Cancel the alarm we set to limit the time taken for
1714 * Inform the channel mechanism that we are the server side and that
1715 * the client may request to connect to any port at all. (The user
1716 * could do it anyway, and we wouldn\'t know what is permitted except
1717 * by the client telling us, so we can equally well trust the client
1718 * not to request anything bogus.)
1720 if (!no_port_forwarding_flag)
1721 channel_permit_all_opens();
1724 * We stay in this loop until the client requests to execute a shell
1729 /* Get a packet from the client. */
1730 type = packet_read(&plen);
1732 /* Process the packet. */
1734 case SSH_CMSG_REQUEST_COMPRESSION:
1735 packet_integrity_check(plen, 4, type);
1736 compression_level = packet_get_int();
1737 if (compression_level < 1 || compression_level > 9) {
1738 packet_send_debug("Received illegal compression level %d.",
1742 /* Enable compression after we have responded with SUCCESS. */
1743 enable_compression_after_reply = 1;
1746 case SSH_CMSG_REQUEST_PTY:
1748 debug("Allocating a pty not permitted for this authentication.");
1752 packet_disconnect("Protocol error: you already have a pty.");
1754 debug("Allocating pty.");
1756 /* Allocate a pty and open it. */
1757 if (!pty_allocate(&ptyfd, &ttyfd, ttyname,
1759 error("Failed to allocate pty.");
1762 fatal_add_cleanup(pty_release_proc, (void *)ttyname);
1763 pty_setowner(pw, ttyname);
1765 /* Get TERM from the packet. Note that the value may be of arbitrary length. */
1766 term = packet_get_string(&dlen);
1767 packet_integrity_check(dlen, strlen(term), type);
1769 /* Remaining bytes */
1770 n_bytes = plen - (4 + dlen + 4 * 4);
1772 if (strcmp(term, "") == 0) {
1777 /* Get window size from the packet. */
1778 row = packet_get_int();
1779 col = packet_get_int();
1780 xpixel = packet_get_int();
1781 ypixel = packet_get_int();
1782 pty_change_window_size(ptyfd, row, col, xpixel, ypixel);
1784 /* Get tty modes from the packet. */
1785 tty_parse_modes(ttyfd, &n_bytes);
1786 packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);
1788 /* Indicate that we now have a pty. */
1792 case SSH_CMSG_X11_REQUEST_FORWARDING:
1793 if (!options.x11_forwarding) {
1794 packet_send_debug("X11 forwarding disabled in server configuration file.");
1798 if (no_x11_forwarding_flag) {
1799 packet_send_debug("X11 forwarding not permitted for this authentication.");
1802 debug("Received request for X11 forwarding with auth spoofing.");
1804 packet_disconnect("Protocol error: X11 display already set.");
1806 unsigned int proto_len, data_len;
1807 proto = packet_get_string(&proto_len);
1808 data = packet_get_string(&data_len);
1809 packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type);
1811 if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER)
1812 screen = packet_get_int();
1815 display = x11_create_display_inet(screen, options.x11_display_offset);
1819 /* Setup to always have a local .Xauthority. */
1820 xauthfile = xmalloc(MAXPATHLEN);
1821 strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
1822 temporarily_use_uid(pw->pw_uid);
1823 if (mkdtemp(xauthfile) == NULL) {
1825 error("private X11 dir: mkdtemp %s failed: %s",
1826 xauthfile, strerror(errno));
1831 strlcat(xauthfile, "/cookies", MAXPATHLEN);
1832 open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
1834 fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
1836 #else /* XAUTH_PATH */
1837 packet_send_debug("No xauth program; cannot forward with spoofing.");
1839 #endif /* XAUTH_PATH */
1841 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1842 if (no_agent_forwarding_flag || compat13) {
1843 debug("Authentication agent forwarding not permitted for this authentication.");
1846 debug("Received authentication agent forwarding request.");
1847 auth_input_request_forwarding(pw);
1850 case SSH_CMSG_PORT_FORWARD_REQUEST:
1851 if (no_port_forwarding_flag) {
1852 debug("Port forwarding not permitted for this authentication.");
1855 debug("Received TCP/IP port forwarding request.");
1856 channel_input_port_forward_request(pw->pw_uid == 0);
1859 case SSH_CMSG_MAX_PACKET_SIZE:
1860 if (packet_set_maxsize(packet_get_int()) < 0)
1864 case SSH_CMSG_EXEC_SHELL:
1865 /* Set interactive/non-interactive mode. */
1866 packet_set_interactive(have_pty || display != NULL,
1867 options.keepalives);
1869 if (forced_command != NULL)
1870 goto do_forced_command;
1871 debug("Forking shell.");
1872 packet_integrity_check(plen, 0, type);
1874 do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1876 do_exec_no_pty(NULL, pw, display, proto, data);
1879 case SSH_CMSG_EXEC_CMD:
1880 /* Set interactive/non-interactive mode. */
1881 packet_set_interactive(have_pty || display != NULL,
1882 options.keepalives);
1884 if (forced_command != NULL)
1885 goto do_forced_command;
1886 /* Get command from the packet. */
1889 command = packet_get_string(&dlen);
1890 debug("Executing command '%.500s'", command);
1891 packet_integrity_check(plen, 4 + dlen, type);
1894 do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1896 do_exec_no_pty(command, pw, display, proto, data);
1902 * Any unknown messages in this phase are ignored,
1903 * and a failure message is returned.
1905 log("Unknown packet type received after authentication: %d", type);
1909 /* The request was successfully processed. */
1910 packet_start(SSH_SMSG_SUCCESS);
1912 packet_write_wait();
1914 /* Enable compression now that we have replied if appropriate. */
1915 if (enable_compression_after_reply) {
1916 enable_compression_after_reply = 0;
1917 packet_start_compression(compression_level);
1922 /* The request failed. */
1923 packet_start(SSH_SMSG_FAILURE);
1925 packet_write_wait();
1930 * There is a forced command specified for this login.
1933 debug("Executing forced command: %.900s", forced_command);
1935 do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1937 do_exec_no_pty(forced_command, pw, display, proto, data);
1943 * This is called to fork and execute a command when we have no tty. This
1944 * will call do_child from the child, and server_loop from the parent after
1945 * setting up file descriptors and such.
1948 do_exec_no_pty(const char *command, struct passwd * pw,
1949 const char *display, const char *auth_proto,
1950 const char *auth_data)
1955 int pin[2], pout[2], perr[2];
1956 /* Allocate pipes for communicating with the program. */
1957 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
1958 packet_disconnect("Could not create pipes: %.100s",
1960 #else /* USE_PIPES */
1961 int inout[2], err[2];
1962 /* Uses socket pairs to communicate with the program. */
1963 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
1964 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
1965 packet_disconnect("Could not create socket pairs: %.100s",
1967 #endif /* USE_PIPES */
1969 setproctitle("%s@notty", pw->pw_name);
1973 #endif /* USE_PAM */
1975 /* Fork the child. */
1976 if ((pid = fork()) == 0) {
1977 /* Child. Reinitialize the log since the pid has changed. */
1978 log_init(av0, options.log_level, options.log_facility, log_stderr);
1981 * Create a new session and process group since the 4.4BSD
1982 * setlogin() affects the entire process group.
1985 error("setsid failed: %.100s", strerror(errno));
1989 * Redirect stdin. We close the parent side of the socket
1990 * pair, and make the child side the standard input.
1993 if (dup2(pin[0], 0) < 0)
1994 perror("dup2 stdin");
1997 /* Redirect stdout. */
1999 if (dup2(pout[1], 1) < 0)
2000 perror("dup2 stdout");
2003 /* Redirect stderr. */
2005 if (dup2(perr[1], 2) < 0)
2006 perror("dup2 stderr");
2008 #else /* USE_PIPES */
2010 * Redirect stdin, stdout, and stderr. Stdin and stdout will
2011 * use the same socket, as some programs (particularly rdist)
2012 * seem to depend on it.
2016 if (dup2(inout[0], 0) < 0) /* stdin */
2017 perror("dup2 stdin");
2018 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
2019 perror("dup2 stdout");
2020 if (dup2(err[0], 2) < 0) /* stderr */
2021 perror("dup2 stderr");
2022 #endif /* USE_PIPES */
2024 /* Do processing for the child (exec command etc). */
2025 do_child(command, pw, NULL, display, auth_proto, auth_data, NULL);
2029 packet_disconnect("fork failed: %.100s", strerror(errno));
2031 /* We are the parent. Close the child sides of the pipes. */
2036 /* Enter the interactive session. */
2037 server_loop(pid, pin[1], pout[0], perr[0]);
2038 /* server_loop has closed pin[1], pout[1], and perr[1]. */
2039 #else /* USE_PIPES */
2040 /* We are the parent. Close the child sides of the socket pairs. */
2045 * Enter the interactive session. Note: server_loop must be able to
2046 * handle the case that fdin and fdout are the same.
2048 server_loop(pid, inout[1], inout[1], err[1]);
2049 /* server_loop has closed inout[1] and err[1]. */
2050 #endif /* USE_PIPES */
2054 * This is called to fork and execute a command when we have a tty. This
2055 * will call do_child from the child, and server_loop from the parent after
2056 * setting up file descriptors, controlling tty, updating wtmp, utmp,
2057 * lastlog, and other such operations.
2060 do_exec_pty(const char *command, int ptyfd, int ttyfd,
2061 const char *ttyname, struct passwd * pw, const char *term,
2062 const char *display, const char *auth_proto,
2063 const char *auth_data)
2067 const char *hostname;
2068 time_t last_login_time;
2069 char buf[100], *time_string;
2074 struct sockaddr_storage from;
2076 struct pty_cleanup_context cleanup_context;
2078 /* Get remote host name. */
2079 hostname = get_canonical_hostname();
2082 * Get the time when the user last logged in. Buf will be set to
2083 * contain the hostname the last login was from.
2085 if (!options.use_login) {
2086 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
2089 setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1);
2092 do_pam_session(pw->pw_name, ttyname);
2094 #endif /* USE_PAM */
2096 /* Fork the child. */
2097 if ((pid = fork()) == 0) {
2100 /* Child. Reinitialize the log because the pid has
2102 log_init(av0, options.log_level, options.log_facility, log_stderr);
2104 /* Close the master side of the pseudo tty. */
2107 /* Make the pseudo tty our controlling tty. */
2108 pty_make_controlling_tty(&ttyfd, ttyname);
2110 /* Redirect stdin from the pseudo tty. */
2111 if (dup2(ttyfd, fileno(stdin)) < 0)
2112 error("dup2 stdin failed: %.100s", strerror(errno));
2114 /* Redirect stdout to the pseudo tty. */
2115 if (dup2(ttyfd, fileno(stdout)) < 0)
2116 error("dup2 stdin failed: %.100s", strerror(errno));
2118 /* Redirect stderr to the pseudo tty. */
2119 if (dup2(ttyfd, fileno(stderr)) < 0)
2120 error("dup2 stdin failed: %.100s", strerror(errno));
2122 /* Close the extra descriptor for the pseudo tty. */
2126 * Get IP address of client. This is needed because we want
2127 * to record where the user logged in from. If the
2128 * connection is not a socket, let the ip address be 0.0.0.0.
2130 memset(&from, 0, sizeof(from));
2131 if (packet_get_connection_in() == packet_get_connection_out()) {
2132 fromlen = sizeof(from);
2133 if (getpeername(packet_get_connection_in(),
2134 (struct sockaddr *) & from, &fromlen) < 0) {
2135 debug("getpeername: %.100s", strerror(errno));
2139 /* Record that there was a login on that terminal. */
2140 record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname,
2141 (struct sockaddr *)&from);
2143 /* Check if .hushlogin exists. */
2144 snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir);
2145 quiet_login = stat(line, &st) >= 0;
2149 print_pam_messages();
2150 #endif /* USE_PAM */
2153 * If the user has logged in before, display the time of last
2154 * login. However, don't display anything extra if a command
2155 * has been specified (so that ssh can be used to execute
2156 * commands on a remote machine without users knowing they
2157 * are going to another machine). Login(1) will do this for
2158 * us as well, so check if login(1) is used
2160 if (command == NULL && last_login_time != 0 && !quiet_login &&
2161 !options.use_login) {
2162 /* Convert the date to a string. */
2163 time_string = ctime(&last_login_time);
2164 /* Remove the trailing newline. */
2165 if (strchr(time_string, '\n'))
2166 *strchr(time_string, '\n') = 0;
2167 /* Display the last login time. Host if displayed
2169 if (strcmp(buf, "") == 0)
2170 printf("Last login: %s\r\n", time_string);
2172 printf("Last login: %s from %s\r\n", time_string, buf);
2175 * Print /etc/motd unless a command was specified or printing
2176 * it was disabled in server options or login(1) will be
2177 * used. Note that some machines appear to print it in
2178 * /etc/profile or similar.
2180 if (command == NULL && options.print_motd && !quiet_login &&
2181 !options.use_login) {
2182 /* Print /etc/motd if it exists. */
2183 f = fopen("/etc/motd", "r");
2185 while (fgets(line, sizeof(line), f))
2186 fputs(line, stdout);
2190 /* Do common processing for the child, such as execing the command. */
2191 do_child(command, pw, term, display, auth_proto, auth_data, ttyname);
2195 packet_disconnect("fork failed: %.100s", strerror(errno));
2196 /* Parent. Close the slave side of the pseudo tty. */
2200 * Add a cleanup function to clear the utmp entry and record logout
2201 * time in case we call fatal() (e.g., the connection gets closed).
2203 cleanup_context.pid = pid;
2204 cleanup_context.ttyname = ttyname;
2205 fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
2206 fatal_remove_cleanup(pty_release_proc, (void *) ttyname);
2209 * Create another descriptor of the pty master side for use as the
2210 * standard input. We could use the original descriptor, but this
2211 * simplifies code in server_loop. The descriptor is bidirectional.
2215 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
2217 /* we keep a reference to the pty master */
2218 ptymaster = dup(ptyfd);
2220 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
2222 /* Enter interactive session. */
2223 server_loop(pid, ptyfd, fdout, -1);
2224 /* server_loop _has_ closed ptyfd and fdout. */
2226 /* Cancel the cleanup function. */
2227 fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
2229 /* Record that the user has logged out. */
2230 record_logout(pid, ttyname);
2232 /* Release the pseudo-tty. */
2233 pty_release(ttyname);
2236 * Close the server side of the socket pairs. We must do this after
2237 * the pty cleanup, so that another process doesn't get this pty
2238 * while we're still cleaning up.
2240 if (close(ptymaster) < 0)
2241 error("close(ptymaster): %s", strerror(errno));
2245 * Sets the value of the given variable in the environment. If the variable
2246 * already exists, its value is overriden.
2249 child_set_env(char ***envp, unsigned int *envsizep, const char *name,
2252 unsigned int i, namelen;
2256 * Find the slot where the value should be stored. If the variable
2257 * already exists, we reuse the slot; otherwise we append a new slot
2258 * at the end of the array, expanding if necessary.
2261 namelen = strlen(name);
2262 for (i = 0; env[i]; i++)
2263 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
2266 /* Reuse the slot. */
2269 /* New variable. Expand if necessary. */
2270 if (i >= (*envsizep) - 1) {
2272 env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
2274 /* Need to set the NULL pointer at end of array beyond the new slot. */
2278 /* Allocate space and format the variable in the appropriate slot. */
2279 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
2280 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
2284 * Reads environment variables from the given file and adds/overrides them
2285 * into the environment. If the file does not exist, this does nothing.
2286 * Otherwise, it must consist of empty lines, comments (line starts with '#')
2287 * and assignments of the form name=value. No other forms are allowed.
2290 read_environment_file(char ***env, unsigned int *envsize,
2291 const char *filename)
2297 f = fopen(filename, "r");
2301 while (fgets(buf, sizeof(buf), f)) {
2302 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
2304 if (!*cp || *cp == '#' || *cp == '\n')
2306 if (strchr(cp, '\n'))
2307 *strchr(cp, '\n') = '\0';
2308 value = strchr(cp, '=');
2309 if (value == NULL) {
2310 fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
2313 /* Replace the equals sign by nul, and advance value to the value string. */
2316 child_set_env(env, envsize, cp, value);
2323 * Sets any environment variables which have been specified by PAM
2325 void do_pam_environment(char ***env, int *envsize)
2327 char *equals, var_name[512], var_val[512];
2331 if ((pam_env = fetch_pam_environment()) == NULL)
2334 for(i = 0; pam_env[i] != NULL; i++) {
2335 if ((equals = strstr(pam_env[i], "=")) == NULL)
2338 if (strlen(pam_env[i]) < (sizeof(var_name) - 1))
2340 memset(var_name, '\0', sizeof(var_name));
2341 memset(var_val, '\0', sizeof(var_val));
2343 strncpy(var_name, pam_env[i], equals - pam_env[i]);
2344 strcpy(var_val, equals + 1);
2346 debug("PAM environment: %s=%s", var_name, var_val);
2348 child_set_env(env, envsize, var_name, var_val);
2352 #endif /* USE_PAM */
2355 * Performs common processing for the child, such as setting up the
2356 * environment, closing extra file descriptors, setting the user and group
2357 * ids, and executing the command or shell.
2360 do_child(const char *command, struct passwd * pw, const char *term,
2361 const char *display, const char *auth_proto,
2362 const char *auth_data, const char *ttyname)
2364 const char *shell, *cp = NULL;
2367 unsigned int envsize, i;
2369 extern char **environ;
2373 #ifndef USE_PAM /* pam_nologin handles this */
2374 /* Check /etc/nologin. */
2375 f = fopen("/etc/nologin", "r");
2377 /* /etc/nologin exists. Print its contents and exit. */
2378 while (fgets(buf, sizeof(buf), f))
2381 if (pw->pw_uid != 0)
2384 #endif /* USE_PAM */
2386 /* Set login name in the kernel. */
2387 if (setlogin(pw->pw_name) < 0)
2388 error("setlogin failed: %s", strerror(errno));
2390 /* Set uid, gid, and groups. */
2391 /* Login(1) does this as well, and it needs uid 0 for the "-h"
2392 switch, so we let login(1) to this for us. */
2393 if (!options.use_login) {
2394 if (getuid() == 0 || geteuid() == 0) {
2395 if (setgid(pw->pw_gid) < 0) {
2399 /* Initialize the group list. */
2400 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
2401 perror("initgroups");
2406 /* Permanently switch to the desired uid. */
2407 permanently_set_uid(pw->pw_uid);
2409 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
2410 fatal("Failed to set uids to %d.", (int) pw->pw_uid);
2413 * Get the shell from the password data. An empty shell field is
2414 * legal, and means /bin/sh.
2416 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
2419 /* Try to get AFS tokens for the local cell. */
2423 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
2424 krb_afslog(cell, 0);
2430 /* Initialize the environment. */
2432 env = xmalloc(envsize * sizeof(char *));
2435 if (!options.use_login) {
2436 /* Set basic environment. */
2437 child_set_env(&env, &envsize, "USER", pw->pw_name);
2438 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
2439 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
2440 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
2442 snprintf(buf, sizeof buf, "%.200s/%.50s",
2443 _PATH_MAILDIR, pw->pw_name);
2444 child_set_env(&env, &envsize, "MAIL", buf);
2446 /* Normal systems set SHELL by default. */
2447 child_set_env(&env, &envsize, "SHELL", shell);
2450 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
2452 /* Set custom environment options from RSA authentication. */
2453 while (custom_environment) {
2454 struct envstring *ce = custom_environment;
2457 for (i = 0; s[i] != '=' && s[i]; i++);
2460 child_set_env(&env, &envsize, s, s + i + 1);
2462 custom_environment = ce->next;
2467 snprintf(buf, sizeof buf, "%.50s %d %d",
2468 get_remote_ipaddr(), get_remote_port(), get_local_port());
2469 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
2472 child_set_env(&env, &envsize, "SSH_TTY", ttyname);
2474 child_set_env(&env, &envsize, "TERM", term);
2476 child_set_env(&env, &envsize, "DISPLAY", display);
2480 char *authstate,*krb5cc;
2482 if ((authstate = getenv("AUTHSTATE")) != NULL)
2483 child_set_env(&env,&envsize,"AUTHSTATE",authstate);
2485 if ((krb5cc = getenv("KRB5CCNAME")) != NULL)
2486 child_set_env(&env,&envsize,"KRB5CCNAME",krb5cc);
2492 extern char *ticket;
2495 child_set_env(&env, &envsize, "KRBTKFILE", ticket);
2500 /* Pull in any environment variables that may have been set by PAM. */
2501 do_pam_environment(&env, &envsize);
2502 #endif /* USE_PAM */
2505 child_set_env(&env, &envsize, "XAUTHORITY", xauthfile);
2507 if (auth_get_socket_name() != NULL)
2508 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
2509 auth_get_socket_name());
2511 read_environment_file(&env,&envsize,"/etc/environment");
2513 /* read $HOME/.ssh/environment. */
2514 if (!options.use_login) {
2515 snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir);
2516 read_environment_file(&env, &envsize, buf);
2519 /* dump the environment */
2520 fprintf(stderr, "Environment:\n");
2521 for (i = 0; env[i]; i++)
2522 fprintf(stderr, " %.200s\n", env[i]);
2525 * Close the connection descriptors; note that this is the child, and
2526 * the server will still have the socket open, and it is important
2527 * that we do not shutdown it. Note that the descriptors cannot be
2528 * closed before building the environment, as we call
2529 * get_remote_ipaddr there.
2531 if (packet_get_connection_in() == packet_get_connection_out())
2532 close(packet_get_connection_in());
2534 close(packet_get_connection_in());
2535 close(packet_get_connection_out());
2538 * Close all descriptors related to channels. They will still remain
2539 * open in the parent.
2541 /* XXX better use close-on-exec? -markus */
2542 channel_close_all();
2545 * Close any extra file descriptors. Note that there may still be
2546 * descriptors left by system functions. They will be closed later.
2551 * Close any extra open file descriptors so that we don\'t have them
2552 * hanging around in clients. Note that we want to do this after
2553 * initgroups, because at least on Solaris 2.3 it leaves file
2556 for (i = 3; i < 64; i++)
2559 /* Change current directory to the user\'s home directory. */
2560 if (chdir(pw->pw_dir) < 0)
2561 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
2562 pw->pw_dir, strerror(errno));
2565 * Must take new environment into use so that .ssh/rc, /etc/sshrc and
2566 * xauth are run in the proper environment.
2571 * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
2574 if (!options.use_login) {
2575 if (stat(SSH_USER_RC, &st) >= 0) {
2577 fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC);
2579 f = popen("/bin/sh " SSH_USER_RC, "w");
2581 if (auth_proto != NULL && auth_data != NULL)
2582 fprintf(f, "%s %s\n", auth_proto, auth_data);
2585 fprintf(stderr, "Could not run %s\n", SSH_USER_RC);
2586 } else if (stat(SSH_SYSTEM_RC, &st) >= 0) {
2588 fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC);
2590 f = popen("/bin/sh " SSH_SYSTEM_RC, "w");
2592 if (auth_proto != NULL && auth_data != NULL)
2593 fprintf(f, "%s %s\n", auth_proto, auth_data);
2596 fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC);
2600 /* Add authority data to .Xauthority if appropriate. */
2601 if (auth_proto != NULL && auth_data != NULL) {
2603 fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n",
2604 XAUTH_PATH, display, auth_proto, auth_data);
2606 f = popen(XAUTH_PATH " -q -", "w");
2608 fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data);
2611 fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH);
2614 #endif /* XAUTH_PATH */
2616 /* Get the last component of the shell name. */
2617 cp = strrchr(shell, '/');
2624 * If we have no command, execute the shell. In this case, the shell
2625 * name to be passed in argv[0] is preceded by '-' to indicate that
2626 * this is a login shell.
2629 if (!options.use_login) {
2633 * Check for mail if we have a tty and it was enabled
2634 * in server options.
2636 if (ttyname && options.check_mail) {
2638 struct stat mailstat;
2639 mailbox = getenv("MAIL");
2640 if (mailbox != NULL) {
2641 if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0)
2642 printf("No mail.\n");
2643 else if (mailstat.st_mtime < mailstat.st_atime)
2644 printf("You have mail.\n");
2646 printf("You have new mail.\n");
2649 /* Start the shell. Set initial character to '-'. */
2651 strncpy(buf + 1, cp, sizeof(buf) - 1);
2652 buf[sizeof(buf) - 1] = 0;
2654 /* Execute the shell. */
2657 execve(shell, argv, env);
2659 /* Executing the shell failed. */
2664 /* Launch login(1). */
2666 execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(),
2667 "-p", "-f", "--", pw->pw_name, NULL);
2669 /* Login couldn't be executed, die. */
2676 * Execute the command using the user's shell. This uses the -c
2677 * option to execute the command.
2679 argv[0] = (char *) cp;
2681 argv[2] = (char *) command;
2683 execve(shell, argv, env);