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 1.90 2000/03/06 20:29:04 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 /* Close connection cleanly after attack. */
520 cipher_attack_detected = packet_disconnect;
522 /* Start listening for a socket, unless started from inetd. */
525 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
529 /* We intentionally do not close the descriptors 0, 1, and 2
530 as our code for setting the descriptors won\'t work
531 if ttyfd happens to be one of those. */
532 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
534 public_key = RSA_new();
535 sensitive_data.private_key = RSA_new();
537 log("Generating %d bit RSA key.", options.server_key_bits);
538 rsa_generate_key(sensitive_data.private_key, public_key,
539 options.server_key_bits);
541 log("RSA key generation complete.");
543 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
544 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
546 if (num_listen_socks >= MAX_LISTEN_SOCKS)
547 fatal("Too many listen sockets. "
548 "Enlarge MAX_LISTEN_SOCKS");
549 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
550 ntop, sizeof(ntop), strport, sizeof(strport),
551 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
552 error("getnameinfo failed");
555 /* Create socket for listening. */
556 listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
557 if (listen_sock < 0) {
558 /* kernel may not support ipv6 */
559 verbose("socket: %.100s", strerror(errno));
562 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
563 error("listen_sock O_NONBLOCK: %s", strerror(errno));
568 * Set socket options. We try to make the port
569 * reusable and have it close as fast as possible
570 * without waiting in unnecessary wait states on
573 setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
574 (void *) &on, sizeof(on));
577 setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
578 (void *) &linger, sizeof(linger));
580 debug("Bind to port %s on %s.", strport, ntop);
582 /* Bind the socket to the desired port. */
583 if ((bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) &&
585 error("Bind to port %s on %s failed: %.200s.",
586 strport, ntop, strerror(errno));
590 listen_socks[num_listen_socks] = listen_sock;
593 /* Start listening on the port. */
594 log("Server listening on %s port %s.", ntop, strport);
595 if (listen(listen_sock, 5) < 0)
596 fatal("listen: %.100s", strerror(errno));
599 freeaddrinfo(options.listen_addrs);
601 if (!num_listen_socks)
602 fatal("Cannot bind any address.");
606 * Record our pid in /etc/sshd_pid to make it easier
607 * to kill the correct sshd. We don\'t want to do
608 * this before the bind above because the bind will
609 * fail if there already is a daemon, and this will
610 * overwrite any old pid in the file.
612 f = fopen(SSH_DAEMON_PID_FILE, "w");
614 fprintf(f, "%u\n", (unsigned int) getpid());
619 public_key = RSA_new();
620 sensitive_data.private_key = RSA_new();
622 log("Generating %d bit RSA key.", options.server_key_bits);
623 rsa_generate_key(sensitive_data.private_key, public_key,
624 options.server_key_bits);
626 log("RSA key generation complete.");
628 /* Schedule server key regeneration alarm. */
629 signal(SIGALRM, key_regeneration_alarm);
630 alarm(options.key_regeneration_time);
632 /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
633 signal(SIGHUP, sighup_handler);
634 signal(SIGTERM, sigterm_handler);
635 signal(SIGQUIT, sigterm_handler);
637 /* Arrange SIGCHLD to be caught. */
638 signal(SIGCHLD, main_sigchld_handler);
640 /* setup fd set for listen */
642 for (i = 0; i < num_listen_socks; i++)
643 if (listen_socks[i] > maxfd)
644 maxfd = listen_socks[i];
645 fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
646 fdset = (fd_set *)xmalloc(fdsetsz);
649 * Stay listening for connections until the system crashes or
650 * the daemon is killed with a signal.
655 /* Wait in select until there is a connection. */
656 memset(fdset, 0, fdsetsz);
657 for (i = 0; i < num_listen_socks; i++)
658 FD_SET(listen_socks[i], fdset);
659 if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) {
661 error("select: %.100s", strerror(errno));
664 for (i = 0; i < num_listen_socks; i++) {
665 if (!FD_ISSET(listen_socks[i], fdset))
667 fromlen = sizeof(from);
668 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
671 if (errno != EINTR && errno != EWOULDBLOCK)
672 error("accept: %.100s", strerror(errno));
675 if (fcntl(newsock, F_SETFL, 0) < 0) {
676 error("newsock del O_NONBLOCK: %s", strerror(errno));
680 * Got connection. Fork a child to handle it, unless
681 * we are in debugging mode.
685 * In debugging mode. Close the listening
686 * socket, and start processing the
687 * connection without forking.
689 debug("Server will not fork when running in debugging mode.");
690 close_listen_socks();
697 * Normal production daemon. Fork, and have
698 * the child process the connection. The
699 * parent continues listening.
701 if ((pid = fork()) == 0) {
703 * Child. Close the listening socket, and start using the
704 * accepted socket. Reinitialize logging (since our pid has
705 * changed). We break out of the loop to handle the connection.
707 close_listen_socks();
710 log_init(av0, options.log_level, options.log_facility, log_stderr);
715 /* Parent. Stay in the loop. */
717 error("fork: %.100s", strerror(errno));
719 debug("Forked child %d.", pid);
721 /* Mark that the key has been used (it was "given" to the child). */
726 /* Close the new socket (the child is now taking care of it). */
728 } /* for (i = 0; i < num_listen_socks; i++) */
729 /* child process check (or debug mode) */
730 if (num_listen_socks < 0)
735 /* This is the child processing a new connection. */
738 * Disable the key regeneration alarm. We will not regenerate the
739 * key since we are no longer in a position to give it to anyone. We
740 * will not restart on SIGHUP since it no longer makes sense.
743 signal(SIGALRM, SIG_DFL);
744 signal(SIGHUP, SIG_DFL);
745 signal(SIGTERM, SIG_DFL);
746 signal(SIGQUIT, SIG_DFL);
747 signal(SIGCHLD, SIG_DFL);
750 * Set socket options for the connection. We want the socket to
751 * close as fast as possible without waiting for anything. If the
752 * connection is not a socket, these will do nothing.
754 /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
757 setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
760 * Register our connection. This turns encryption off because we do
763 packet_set_connection(sock_in, sock_out);
765 remote_port = get_remote_port();
766 remote_ip = get_remote_ipaddr();
768 /* Check whether logins are denied from this host. */
770 /* XXX LIBWRAP noes not know about IPv6 */
772 struct request_info req;
774 request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL);
777 if (!hosts_access(&req)) {
782 /*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
785 /* Log the connection. */
786 verbose("Connection from %.500s port %d", remote_ip, remote_port);
789 * We don\'t want to listen forever unless the other side
790 * successfully authenticates itself. So we set up an alarm which is
791 * cleared after successful authentication. A limit of zero
792 * indicates no limit. Note that we don\'t set the alarm in debugging
793 * mode; it is just annoying to have the server exit just when you
794 * are about to discover the bug.
796 signal(SIGALRM, grace_alarm_handler);
798 alarm(options.login_grace_time);
800 if (client_version_string != NULL) {
801 /* we are exec'ed by sshd2, so skip exchange of protocol version */
802 strlcpy(buf, client_version_string, sizeof(buf));
804 /* Send our protocol version identification. */
805 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
806 PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
807 if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) {
808 log("Could not write ident string to %s.", remote_ip);
812 /* Read other side\'s version identification. */
813 for (i = 0; i < sizeof(buf) - 1; i++) {
814 if (read(sock_in, &buf[i], 1) != 1) {
815 log("Did not receive ident string from %s.", remote_ip);
818 if (buf[i] == '\r') {
823 if (buf[i] == '\n') {
829 buf[sizeof(buf) - 1] = 0;
833 * Check that the versions match. In future this might accept
834 * several versions and set appropriate flags to handle them.
836 if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor,
837 remote_version) != 3) {
838 char *s = "Protocol mismatch.\n";
840 (void) atomicio(write, sock_out, s, strlen(s));
843 log("Bad protocol version identification '%.100s' from %s",
847 debug("Client protocol version %d.%d; client software version %.100s",
848 remote_major, remote_minor, remote_version);
849 if (remote_major != PROTOCOL_MAJOR) {
850 char *s = "Protocol major versions differ.\n";
852 (void) atomicio(write, sock_out, s, strlen(s));
855 log("Protocol major versions differ for %s: %d vs. %d",
856 remote_ip, PROTOCOL_MAJOR, remote_major);
859 /* Check that the client has sufficiently high software version. */
860 if (remote_major == 1 && remote_minor < 3)
861 packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version.");
863 if (remote_major == 1 && remote_minor == 3) {
864 /* note that this disables agent-forwarding */
868 * Check that the connection comes from a privileged port. Rhosts-
869 * and Rhosts-RSA-Authentication only make sense from priviledged
870 * programs. Of course, if the intruder has root access on his local
871 * machine, he can connect from any port. So do not use these
872 * authentication methods from machines that you do not trust.
874 if (remote_port >= IPPORT_RESERVED ||
875 remote_port < IPPORT_RESERVED / 2) {
876 options.rhosts_authentication = 0;
877 options.rhosts_rsa_authentication = 0;
880 if (!packet_connection_is_ipv4() &&
881 options.kerberos_authentication) {
882 debug("Kerberos Authentication disabled, only available for IPv4.");
883 options.kerberos_authentication = 0;
887 packet_set_nonblocking();
889 /* perform the key exchange */
892 /* authenticate user and start session */
896 /* Cleanup user's ticket cache file. */
897 if (options.kerberos_ticket_cleanup)
901 /* Cleanup user's local Xauthority file. */
903 xauthfile_cleanup_proc(NULL);
905 /* The connection has been terminated. */
906 verbose("Closing connection to %.100s", remote_ip);
924 BIGNUM *session_key_int;
925 unsigned char session_key[SSH_SESSION_KEY_LENGTH];
926 unsigned char cookie[8];
927 unsigned int cipher_type, auth_mask, protocol_flags;
931 * Generate check bytes that the client must send back in the user
932 * packet in order for it to be accepted; this is used to defy ip
933 * spoofing attacks. Note that this only works against somebody
934 * doing IP spoofing from a remote machine; any machine on the local
935 * network can still see outgoing packets and catch the random
936 * cookie. This only affects rhosts authentication, and this is one
937 * of the reasons why it is inherently insecure.
939 for (i = 0; i < 8; i++) {
942 cookie[i] = rand & 0xff;
947 * Send our public key. We include in the packet 64 bits of random
948 * data that must be matched in the reply in order to prevent IP
951 packet_start(SSH_SMSG_PUBLIC_KEY);
952 for (i = 0; i < 8; i++)
953 packet_put_char(cookie[i]);
955 /* Store our public server RSA key. */
956 packet_put_int(BN_num_bits(public_key->n));
957 packet_put_bignum(public_key->e);
958 packet_put_bignum(public_key->n);
960 /* Store our public host RSA key. */
961 packet_put_int(BN_num_bits(sensitive_data.host_key->n));
962 packet_put_bignum(sensitive_data.host_key->e);
963 packet_put_bignum(sensitive_data.host_key->n);
965 /* Put protocol flags. */
966 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
968 /* Declare which ciphers we support. */
969 packet_put_int(cipher_mask());
971 /* Declare supported authentication types. */
973 if (options.rhosts_authentication)
974 auth_mask |= 1 << SSH_AUTH_RHOSTS;
975 if (options.rhosts_rsa_authentication)
976 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
977 if (options.rsa_authentication)
978 auth_mask |= 1 << SSH_AUTH_RSA;
980 if (options.kerberos_authentication)
981 auth_mask |= 1 << SSH_AUTH_KERBEROS;
984 if (options.kerberos_tgt_passing)
985 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
986 if (options.afs_token_passing)
987 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
990 if (options.skey_authentication == 1)
991 auth_mask |= 1 << SSH_AUTH_TIS;
993 if (options.password_authentication)
994 auth_mask |= 1 << SSH_AUTH_PASSWORD;
995 packet_put_int(auth_mask);
997 /* Send the packet and wait for it to be sent. */
1001 debug("Sent %d bit public key and %d bit host key.",
1002 BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n));
1004 /* Read clients reply (cipher type and session key). */
1005 packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
1007 /* Get cipher type and check whether we accept this. */
1008 cipher_type = packet_get_char();
1010 if (!(cipher_mask() & (1 << cipher_type)))
1011 packet_disconnect("Warning: client selects unsupported cipher.");
1013 /* Get check bytes from the packet. These must match those we
1014 sent earlier with the public key packet. */
1015 for (i = 0; i < 8; i++)
1016 if (cookie[i] != packet_get_char())
1017 packet_disconnect("IP Spoofing check bytes do not match.");
1019 debug("Encryption type: %.200s", cipher_name(cipher_type));
1021 /* Get the encrypted integer. */
1022 session_key_int = BN_new();
1023 packet_get_bignum(session_key_int, &slen);
1025 protocol_flags = packet_get_int();
1026 packet_set_protocol_flags(protocol_flags);
1028 packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
1031 * Decrypt it using our private server key and private host key (key
1032 * with larger modulus first).
1034 if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) {
1035 /* Private key has bigger modulus. */
1036 if (BN_num_bits(sensitive_data.private_key->n) <
1037 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
1038 fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1039 get_remote_ipaddr(),
1040 BN_num_bits(sensitive_data.private_key->n),
1041 BN_num_bits(sensitive_data.host_key->n),
1042 SSH_KEY_BITS_RESERVED);
1044 rsa_private_decrypt(session_key_int, session_key_int,
1045 sensitive_data.private_key);
1046 rsa_private_decrypt(session_key_int, session_key_int,
1047 sensitive_data.host_key);
1049 /* Host key has bigger modulus (or they are equal). */
1050 if (BN_num_bits(sensitive_data.host_key->n) <
1051 BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) {
1052 fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d",
1053 get_remote_ipaddr(),
1054 BN_num_bits(sensitive_data.host_key->n),
1055 BN_num_bits(sensitive_data.private_key->n),
1056 SSH_KEY_BITS_RESERVED);
1058 rsa_private_decrypt(session_key_int, session_key_int,
1059 sensitive_data.host_key);
1060 rsa_private_decrypt(session_key_int, session_key_int,
1061 sensitive_data.private_key);
1064 compute_session_id(session_id, cookie,
1065 sensitive_data.host_key->n,
1066 sensitive_data.private_key->n);
1068 /* Destroy the private and public keys. They will no longer be needed. */
1069 RSA_free(public_key);
1070 RSA_free(sensitive_data.private_key);
1071 RSA_free(sensitive_data.host_key);
1074 * Extract session key from the decrypted integer. The key is in the
1075 * least significant 256 bits of the integer; the first byte of the
1076 * key is in the highest bits.
1078 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1079 len = BN_num_bytes(session_key_int);
1080 if (len < 0 || len > sizeof(session_key))
1081 fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d",
1082 get_remote_ipaddr(),
1083 len, sizeof(session_key));
1084 memset(session_key, 0, sizeof(session_key));
1085 BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
1087 /* Destroy the decrypted integer. It is no longer needed. */
1088 BN_clear_free(session_key_int);
1090 /* Xor the first 16 bytes of the session key with the session id. */
1091 for (i = 0; i < 16; i++)
1092 session_key[i] ^= session_id[i];
1094 /* Set the session key. From this on all communications will be encrypted. */
1095 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1097 /* Destroy our copy of the session key. It is no longer needed. */
1098 memset(session_key, 0, sizeof(session_key));
1100 debug("Received session key; encryption turned on.");
1102 /* Send an acknowledgement packet. Note that this packet is sent encrypted. */
1103 packet_start(SSH_SMSG_SUCCESS);
1105 packet_write_wait();
1110 * Check if the user is allowed to log in via ssh. If user is listed in
1111 * DenyUsers or user's primary group is listed in DenyGroups, false will
1112 * be returned. If AllowUsers isn't empty and user isn't listed there, or
1113 * if AllowGroups isn't empty and user isn't listed there, false will be
1115 * If the user's shell is not executable, false will be returned.
1116 * Otherwise true is returned.
1119 allowed_user(struct passwd * pw)
1124 #ifdef WITH_AIXAUTHENTICATE
1126 #endif /* WITH_AIXAUTHENTICATE */
1128 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
1132 /* deny if shell does not exists or is not executable */
1133 if (stat(pw->pw_shell, &st) != 0)
1135 if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP))))
1138 /* Return false if user is listed in DenyUsers */
1139 if (options.num_deny_users > 0) {
1142 for (i = 0; i < options.num_deny_users; i++)
1143 if (match_pattern(pw->pw_name, options.deny_users[i]))
1146 /* Return false if AllowUsers isn't empty and user isn't listed there */
1147 if (options.num_allow_users > 0) {
1150 for (i = 0; i < options.num_allow_users; i++)
1151 if (match_pattern(pw->pw_name, options.allow_users[i]))
1153 /* i < options.num_allow_users iff we break for loop */
1154 if (i >= options.num_allow_users)
1157 /* Get the primary group name if we need it. Return false if it fails */
1158 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
1159 grp = getgrgid(pw->pw_gid);
1163 /* Return false if user's group is listed in DenyGroups */
1164 if (options.num_deny_groups > 0) {
1167 for (i = 0; i < options.num_deny_groups; i++)
1168 if (match_pattern(grp->gr_name, options.deny_groups[i]))
1172 * Return false if AllowGroups isn't empty and user's group
1173 * isn't listed there
1175 if (options.num_allow_groups > 0) {
1178 for (i = 0; i < options.num_allow_groups; i++)
1179 if (match_pattern(grp->gr_name, options.allow_groups[i]))
1181 /* i < options.num_allow_groups iff we break for
1183 if (i >= options.num_allow_groups)
1188 #ifdef WITH_AIXAUTHENTICATE
1189 if (loginrestrictions(pw->pw_name,S_LOGIN,NULL,&loginmsg) != 0)
1191 #endif /* WITH_AIXAUTHENTICATE */
1193 /* We found no reason not to let this user try to log on... */
1198 * Performs authentication of an incoming connection. Session key has already
1199 * been exchanged and encryption is enabled.
1204 struct passwd *pw, pwcopy;
1208 /* Get the name of the user that we wish to log in as. */
1209 packet_read_expect(&plen, SSH_CMSG_USER);
1211 /* Get the user name. */
1212 user = packet_get_string(&ulen);
1213 packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
1215 setproctitle("%s", user);
1217 #ifdef WITH_AIXAUTHENTICATE
1219 #endif /* WITH_AIXAUTHENTICATE */
1222 /* If machine has AFS, set process authentication group. */
1229 /* Verify that the user is a valid user. */
1230 pw = getpwnam(user);
1231 if (!pw || !allowed_user(pw))
1232 do_fake_authloop(user);
1235 /* Take a copy of the returned structure. */
1236 memset(&pwcopy, 0, sizeof(pwcopy));
1237 pwcopy.pw_name = xstrdup(pw->pw_name);
1238 pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
1239 pwcopy.pw_uid = pw->pw_uid;
1240 pwcopy.pw_gid = pw->pw_gid;
1241 pwcopy.pw_dir = xstrdup(pw->pw_dir);
1242 pwcopy.pw_shell = xstrdup(pw->pw_shell);
1250 * If we are not running as root, the user must have the same uid as
1253 if (getuid() != 0 && pw->pw_uid != getuid())
1254 packet_disconnect("Cannot change user when server not running as root.");
1256 debug("Attempting authentication for %.100s.", pw->pw_name);
1258 /* If the user has no password, accept authentication immediately. */
1259 if (options.password_authentication &&
1261 (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
1264 auth_pam_password(pw, "")) {
1266 auth_password(pw, "")) {
1267 #endif /* USE_PAM */
1268 /* Authentication with empty password succeeded. */
1269 log("Login for user %s from %.100s, accepted without authentication.",
1270 pw->pw_name, get_remote_ipaddr());
1272 /* Loop until the user has been authenticated or the
1273 connection is closed, do_authloop() returns only if
1274 authentication is successfull */
1278 /* Check if the user is logging in as root and root logins are disallowed. */
1279 if (pw->pw_uid == 0 && !options.permit_root_login) {
1281 log("Root login accepted for forced command.");
1283 packet_disconnect("ROOT LOGIN REFUSED FROM %.200s",
1284 get_canonical_hostname());
1286 /* The user has been authenticated and accepted. */
1287 #ifdef WITH_AIXAUTHENTICATE
1288 loginsuccess(user,get_canonical_hostname(),"ssh",&loginmsg);
1289 #endif /* WITH_AIXAUTHENTICATE */
1290 packet_start(SSH_SMSG_SUCCESS);
1292 packet_write_wait();
1294 /* Perform session preparation. */
1295 do_authenticated(pw);
1298 #define AUTH_FAIL_MAX 6
1299 #define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2)
1300 #define AUTH_FAIL_MSG "Too many authentication failures for %.100s"
1303 * read packets and try to authenticate local user *pw.
1304 * return if authentication is successfull
1307 do_authloop(struct passwd * pw)
1311 BIGNUM *client_host_key_e, *client_host_key_n;
1313 char *client_user = NULL, *password = NULL;
1315 int plen, dlen, nlen, ulen, elen;
1317 void (*authlog) (const char *fmt,...) = verbose;
1319 /* Indicate that authentication is needed. */
1320 packet_start(SSH_SMSG_FAILURE);
1322 packet_write_wait();
1324 for (attempt = 1;; attempt++) {
1325 int authenticated = 0;
1326 strlcpy(user, "", sizeof user);
1328 /* Get a packet from the client. */
1329 type = packet_read(&plen);
1331 /* Process the packet. */
1334 case SSH_CMSG_HAVE_KERBEROS_TGT:
1335 if (!options.kerberos_tgt_passing) {
1336 /* packet_get_all(); */
1337 verbose("Kerberos tgt passing disabled.");
1340 /* Accept Kerberos tgt. */
1341 char *tgt = packet_get_string(&dlen);
1342 packet_integrity_check(plen, 4 + dlen, type);
1343 if (!auth_kerberos_tgt(pw, tgt))
1344 verbose("Kerberos tgt REFUSED for %s", pw->pw_name);
1349 case SSH_CMSG_HAVE_AFS_TOKEN:
1350 if (!options.afs_token_passing || !k_hasafs()) {
1351 /* packet_get_all(); */
1352 verbose("AFS token passing disabled.");
1355 /* Accept AFS token. */
1356 char *token_string = packet_get_string(&dlen);
1357 packet_integrity_check(plen, 4 + dlen, type);
1358 if (!auth_afs_token(pw, token_string))
1359 verbose("AFS token REFUSED for %s", pw->pw_name);
1360 xfree(token_string);
1365 case SSH_CMSG_AUTH_KERBEROS:
1366 if (!options.kerberos_authentication) {
1367 /* packet_get_all(); */
1368 verbose("Kerberos authentication disabled.");
1371 /* Try Kerberos v4 authentication. */
1373 char *tkt_user = NULL;
1374 char *kdata = packet_get_string((unsigned int *) &auth.length);
1375 packet_integrity_check(plen, 4 + auth.length, type);
1377 if (auth.length < MAX_KTXT_LEN)
1378 memcpy(auth.dat, kdata, auth.length);
1381 authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
1383 if (authenticated) {
1384 snprintf(user, sizeof user, " tktuser %s", tkt_user);
1391 case SSH_CMSG_AUTH_RHOSTS:
1392 if (!options.rhosts_authentication) {
1393 verbose("Rhosts authentication disabled.");
1397 * Get client user name. Note that we just have to
1398 * trust the client; this is one reason why rhosts
1399 * authentication is insecure. (Another is
1400 * IP-spoofing on a local network.)
1402 client_user = packet_get_string(&ulen);
1403 packet_integrity_check(plen, 4 + ulen, type);
1405 /* Try to authenticate using /etc/hosts.equiv and
1407 authenticated = auth_rhosts(pw, client_user);
1409 snprintf(user, sizeof user, " ruser %s", client_user);
1412 case SSH_CMSG_AUTH_RHOSTS_RSA:
1413 if (!options.rhosts_rsa_authentication) {
1414 verbose("Rhosts with RSA authentication disabled.");
1418 * Get client user name. Note that we just have to
1419 * trust the client; root on the client machine can
1420 * claim to be any user.
1422 client_user = packet_get_string(&ulen);
1424 /* Get the client host key. */
1425 client_host_key_e = BN_new();
1426 client_host_key_n = BN_new();
1427 bits = packet_get_int();
1428 packet_get_bignum(client_host_key_e, &elen);
1429 packet_get_bignum(client_host_key_n, &nlen);
1431 if (bits != BN_num_bits(client_host_key_n))
1432 error("Warning: keysize mismatch for client_host_key: "
1433 "actual %d, announced %d", BN_num_bits(client_host_key_n), bits);
1434 packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
1436 authenticated = auth_rhosts_rsa(pw, client_user,
1437 client_host_key_e, client_host_key_n);
1438 BN_clear_free(client_host_key_e);
1439 BN_clear_free(client_host_key_n);
1441 snprintf(user, sizeof user, " ruser %s", client_user);
1444 case SSH_CMSG_AUTH_RSA:
1445 if (!options.rsa_authentication) {
1446 verbose("RSA authentication disabled.");
1449 /* RSA authentication requested. */
1451 packet_get_bignum(n, &nlen);
1452 packet_integrity_check(plen, nlen, type);
1453 authenticated = auth_rsa(pw, n);
1457 case SSH_CMSG_AUTH_PASSWORD:
1458 if (!options.password_authentication) {
1459 verbose("Password authentication disabled.");
1463 * Read user password. It is in plain text, but was
1464 * transmitted over the encrypted channel so it is
1465 * not visible to an outside observer.
1467 password = packet_get_string(&dlen);
1468 packet_integrity_check(plen, 4 + dlen, type);
1471 /* Do PAM auth with password */
1472 authenticated = auth_pam_password(pw, password);
1474 /* Try authentication with the password. */
1475 authenticated = auth_password(pw, password);
1476 #endif /* USE_PAM */
1477 memset(password, 0, strlen(password));
1482 case SSH_CMSG_AUTH_TIS:
1483 debug("rcvd SSH_CMSG_AUTH_TIS");
1484 if (options.skey_authentication == 1) {
1485 char *skeyinfo = skey_keyinfo(pw->pw_name);
1486 if (skeyinfo == NULL) {
1487 debug("generating fake skeyinfo for %.100s.", pw->pw_name);
1488 skeyinfo = skey_fake_keyinfo(pw->pw_name);
1490 if (skeyinfo != NULL) {
1491 /* we send our s/key- in tis-challenge messages */
1492 debug("sending challenge '%s'", skeyinfo);
1493 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1494 packet_put_string(skeyinfo, strlen(skeyinfo));
1496 packet_write_wait();
1501 case SSH_CMSG_AUTH_TIS_RESPONSE:
1502 debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
1503 if (options.skey_authentication == 1) {
1504 char *response = packet_get_string(&dlen);
1505 debug("skey response == '%s'", response);
1506 packet_integrity_check(plen, 4 + dlen, type);
1507 authenticated = (skey_haskey(pw->pw_name) == 0 &&
1508 skey_passcheck(pw->pw_name, response) != -1);
1513 case SSH_CMSG_AUTH_TIS:
1514 /* TIS Authentication is unsupported */
1515 log("TIS authentication unsupported.");
1521 * Any unknown messages will be ignored (and failure
1522 * returned) during authentication.
1524 log("Unknown message during authentication: type %d", type);
1528 /* Raise logging level */
1529 if (authenticated ||
1530 attempt == AUTH_FAIL_LOG ||
1531 type == SSH_CMSG_AUTH_PASSWORD)
1534 authlog("%s %s for %.200s from %.200s port %d%s",
1535 authenticated ? "Accepted" : "Failed",
1537 pw->pw_uid == 0 ? "ROOT" : pw->pw_name,
1538 get_remote_ipaddr(),
1543 if (authenticated) {
1544 if (!do_pam_account(pw->pw_name, client_user)) {
1545 if (client_user != NULL) {
1549 do_fake_authloop(pw->pw_name);
1554 if (authenticated) {
1557 #endif /* USE_PAM */
1559 if (client_user != NULL) {
1564 if (attempt > AUTH_FAIL_MAX)
1565 packet_disconnect(AUTH_FAIL_MSG, pw->pw_name);
1567 /* Send a message indicating that the authentication attempt failed. */
1568 packet_start(SSH_SMSG_FAILURE);
1570 packet_write_wait();
1575 * The user does not exist or access is denied,
1576 * but fake indication that authentication is needed.
1579 do_fake_authloop(char *user)
1583 log("Faking authloop for illegal user %.200s from %.200s port %d",
1585 get_remote_ipaddr(),
1588 /* Indicate that authentication is needed. */
1589 packet_start(SSH_SMSG_FAILURE);
1591 packet_write_wait();
1594 * Keep reading packets, and always respond with a failure. This is
1595 * to avoid disclosing whether such a user really exists.
1597 for (attempt = 1;; attempt++) {
1598 /* Read a packet. This will not return if the client disconnects. */
1601 (void)packet_read(&plen);
1603 int type = packet_read(&plen);
1605 char *password, *skeyinfo;
1606 /* Try to send a fake s/key challenge. */
1607 if (options.skey_authentication == 1 &&
1608 (skeyinfo = skey_fake_keyinfo(user)) != NULL) {
1610 if (type == SSH_CMSG_AUTH_TIS) {
1611 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1612 packet_put_string(skeyinfo, strlen(skeyinfo));
1614 packet_write_wait();
1616 } else if (type == SSH_CMSG_AUTH_PASSWORD &&
1617 options.password_authentication &&
1618 (password = packet_get_string(&dlen)) != NULL &&
1620 strncasecmp(password, "s/key", 5) == 0 ) {
1621 packet_send_debug(skeyinfo);
1623 if (password != NULL)
1627 if (attempt > AUTH_FAIL_MAX)
1628 packet_disconnect(AUTH_FAIL_MSG, user);
1631 * Send failure. This should be indistinguishable from a
1632 * failed authentication.
1634 packet_start(SSH_SMSG_FAILURE);
1636 packet_write_wait();
1637 #ifdef WITH_AIXAUTHENTICATE
1638 if (strncmp(get_authname(type),"password",
1639 strlen(get_authname(type))) == 0)
1640 loginfailed(pw->pw_name,get_canonical_hostname(),"ssh");
1641 #endif /* WITH_AIXAUTHENTICATE */
1647 struct pty_cleanup_context {
1648 const char *ttyname;
1653 * Function to perform cleanup if we get aborted abnormally (e.g., due to a
1654 * dropped connection).
1657 pty_cleanup_proc(void *context)
1659 struct pty_cleanup_context *cu = context;
1661 debug("pty_cleanup_proc called");
1663 /* Record that the user has logged out. */
1664 record_logout(cu->pid, cu->ttyname);
1666 /* Release the pseudo-tty. */
1667 pty_release(cu->ttyname);
1670 /* simple cleanup: chown tty slave back to root */
1672 pty_release_proc(void *tty)
1674 char *ttyname = tty;
1675 pty_release(ttyname);
1679 * Prepares for an interactive session. This is called after the user has
1680 * been successfully authenticated. During this message exchange, pseudo
1681 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
1682 * are requested, etc.
1685 do_authenticated(struct passwd * pw)
1688 int compression_level = 0, enable_compression_after_reply = 0;
1689 int have_pty = 0, ptyfd = -1, ttyfd = -1;
1690 int row, col, xpixel, ypixel, screen;
1692 char *command, *term = NULL, *display = NULL, *proto = NULL, *data = NULL;
1696 * Cancel the alarm we set to limit the time taken for
1702 * Inform the channel mechanism that we are the server side and that
1703 * the client may request to connect to any port at all. (The user
1704 * could do it anyway, and we wouldn\'t know what is permitted except
1705 * by the client telling us, so we can equally well trust the client
1706 * not to request anything bogus.)
1708 if (!no_port_forwarding_flag)
1709 channel_permit_all_opens();
1712 * We stay in this loop until the client requests to execute a shell
1718 /* Get a packet from the client. */
1719 type = packet_read(&plen);
1721 /* Process the packet. */
1723 case SSH_CMSG_REQUEST_COMPRESSION:
1724 packet_integrity_check(plen, 4, type);
1725 compression_level = packet_get_int();
1726 if (compression_level < 1 || compression_level > 9) {
1727 packet_send_debug("Received illegal compression level %d.",
1731 /* Enable compression after we have responded with SUCCESS. */
1732 enable_compression_after_reply = 1;
1735 case SSH_CMSG_REQUEST_PTY:
1737 debug("Allocating a pty not permitted for this authentication.");
1741 packet_disconnect("Protocol error: you already have a pty.");
1743 debug("Allocating pty.");
1745 /* Allocate a pty and open it. */
1746 if (!pty_allocate(&ptyfd, &ttyfd, ttyname,
1748 error("Failed to allocate pty.");
1751 fatal_add_cleanup(pty_release_proc, (void *)ttyname);
1752 pty_setowner(pw, ttyname);
1754 /* Get TERM from the packet. Note that the value may be of arbitrary length. */
1755 term = packet_get_string(&dlen);
1756 packet_integrity_check(dlen, strlen(term), type);
1758 /* Remaining bytes */
1759 n_bytes = plen - (4 + dlen + 4 * 4);
1761 if (strcmp(term, "") == 0) {
1766 /* Get window size from the packet. */
1767 row = packet_get_int();
1768 col = packet_get_int();
1769 xpixel = packet_get_int();
1770 ypixel = packet_get_int();
1771 pty_change_window_size(ptyfd, row, col, xpixel, ypixel);
1773 /* Get tty modes from the packet. */
1774 tty_parse_modes(ttyfd, &n_bytes);
1775 packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);
1777 /* Indicate that we now have a pty. */
1781 case SSH_CMSG_X11_REQUEST_FORWARDING:
1782 if (!options.x11_forwarding) {
1783 packet_send_debug("X11 forwarding disabled in server configuration file.");
1787 if (no_x11_forwarding_flag) {
1788 packet_send_debug("X11 forwarding not permitted for this authentication.");
1791 debug("Received request for X11 forwarding with auth spoofing.");
1793 packet_disconnect("Protocol error: X11 display already set.");
1795 int proto_len, data_len;
1796 proto = packet_get_string(&proto_len);
1797 data = packet_get_string(&data_len);
1798 packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type);
1800 if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER)
1801 screen = packet_get_int();
1804 display = x11_create_display_inet(screen, options.x11_display_offset);
1808 /* Setup to always have a local .Xauthority. */
1809 xauthfile = xmalloc(MAXPATHLEN);
1810 strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
1811 temporarily_use_uid(pw->pw_uid);
1812 if (mkdtemp(xauthfile) == NULL) {
1814 error("private X11 dir: mkdtemp %s failed: %s",
1815 xauthfile, strerror(errno));
1820 strlcat(xauthfile, "/cookies", MAXPATHLEN);
1821 open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
1823 fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
1825 #else /* XAUTH_PATH */
1826 packet_send_debug("No xauth program; cannot forward with spoofing.");
1828 #endif /* XAUTH_PATH */
1830 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1831 if (no_agent_forwarding_flag || compat13) {
1832 debug("Authentication agent forwarding not permitted for this authentication.");
1835 debug("Received authentication agent forwarding request.");
1836 auth_input_request_forwarding(pw);
1839 case SSH_CMSG_PORT_FORWARD_REQUEST:
1840 if (no_port_forwarding_flag) {
1841 debug("Port forwarding not permitted for this authentication.");
1844 debug("Received TCP/IP port forwarding request.");
1845 channel_input_port_forward_request(pw->pw_uid == 0);
1848 case SSH_CMSG_MAX_PACKET_SIZE:
1849 if (packet_set_maxsize(packet_get_int()) < 0)
1853 case SSH_CMSG_EXEC_SHELL:
1854 /* Set interactive/non-interactive mode. */
1855 packet_set_interactive(have_pty || display != NULL,
1856 options.keepalives);
1858 if (forced_command != NULL)
1859 goto do_forced_command;
1860 debug("Forking shell.");
1861 packet_integrity_check(plen, 0, type);
1863 do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1865 do_exec_no_pty(NULL, pw, display, proto, data);
1868 case SSH_CMSG_EXEC_CMD:
1869 /* Set interactive/non-interactive mode. */
1870 packet_set_interactive(have_pty || display != NULL,
1871 options.keepalives);
1873 if (forced_command != NULL)
1874 goto do_forced_command;
1875 /* Get command from the packet. */
1878 command = packet_get_string(&dlen);
1879 debug("Executing command '%.500s'", command);
1880 packet_integrity_check(plen, 4 + dlen, type);
1883 do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1885 do_exec_no_pty(command, pw, display, proto, data);
1891 * Any unknown messages in this phase are ignored,
1892 * and a failure message is returned.
1894 log("Unknown packet type received after authentication: %d", type);
1898 /* The request was successfully processed. */
1899 packet_start(SSH_SMSG_SUCCESS);
1901 packet_write_wait();
1903 /* Enable compression now that we have replied if appropriate. */
1904 if (enable_compression_after_reply) {
1905 enable_compression_after_reply = 0;
1906 packet_start_compression(compression_level);
1911 /* The request failed. */
1912 packet_start(SSH_SMSG_FAILURE);
1914 packet_write_wait();
1919 * There is a forced command specified for this login.
1922 debug("Executing forced command: %.900s", forced_command);
1924 do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1926 do_exec_no_pty(forced_command, pw, display, proto, data);
1932 * This is called to fork and execute a command when we have no tty. This
1933 * will call do_child from the child, and server_loop from the parent after
1934 * setting up file descriptors and such.
1937 do_exec_no_pty(const char *command, struct passwd * pw,
1938 const char *display, const char *auth_proto,
1939 const char *auth_data)
1944 int pin[2], pout[2], perr[2];
1945 /* Allocate pipes for communicating with the program. */
1946 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
1947 packet_disconnect("Could not create pipes: %.100s",
1949 #else /* USE_PIPES */
1950 int inout[2], err[2];
1951 /* Uses socket pairs to communicate with the program. */
1952 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
1953 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
1954 packet_disconnect("Could not create socket pairs: %.100s",
1956 #endif /* USE_PIPES */
1958 setproctitle("%s@notty", pw->pw_name);
1962 #endif /* USE_PAM */
1964 /* Fork the child. */
1965 if ((pid = fork()) == 0) {
1966 /* Child. Reinitialize the log since the pid has changed. */
1967 log_init(av0, options.log_level, options.log_facility, log_stderr);
1970 * Create a new session and process group since the 4.4BSD
1971 * setlogin() affects the entire process group.
1974 error("setsid failed: %.100s", strerror(errno));
1978 * Redirect stdin. We close the parent side of the socket
1979 * pair, and make the child side the standard input.
1982 if (dup2(pin[0], 0) < 0)
1983 perror("dup2 stdin");
1986 /* Redirect stdout. */
1988 if (dup2(pout[1], 1) < 0)
1989 perror("dup2 stdout");
1992 /* Redirect stderr. */
1994 if (dup2(perr[1], 2) < 0)
1995 perror("dup2 stderr");
1997 #else /* USE_PIPES */
1999 * Redirect stdin, stdout, and stderr. Stdin and stdout will
2000 * use the same socket, as some programs (particularly rdist)
2001 * seem to depend on it.
2005 if (dup2(inout[0], 0) < 0) /* stdin */
2006 perror("dup2 stdin");
2007 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
2008 perror("dup2 stdout");
2009 if (dup2(err[0], 2) < 0) /* stderr */
2010 perror("dup2 stderr");
2011 #endif /* USE_PIPES */
2013 /* Do processing for the child (exec command etc). */
2014 do_child(command, pw, NULL, display, auth_proto, auth_data, NULL);
2018 packet_disconnect("fork failed: %.100s", strerror(errno));
2020 /* We are the parent. Close the child sides of the pipes. */
2025 /* Enter the interactive session. */
2026 server_loop(pid, pin[1], pout[0], perr[0]);
2027 /* server_loop has closed pin[1], pout[1], and perr[1]. */
2028 #else /* USE_PIPES */
2029 /* We are the parent. Close the child sides of the socket pairs. */
2034 * Enter the interactive session. Note: server_loop must be able to
2035 * handle the case that fdin and fdout are the same.
2037 server_loop(pid, inout[1], inout[1], err[1]);
2038 /* server_loop has closed inout[1] and err[1]. */
2039 #endif /* USE_PIPES */
2043 * This is called to fork and execute a command when we have a tty. This
2044 * will call do_child from the child, and server_loop from the parent after
2045 * setting up file descriptors, controlling tty, updating wtmp, utmp,
2046 * lastlog, and other such operations.
2049 do_exec_pty(const char *command, int ptyfd, int ttyfd,
2050 const char *ttyname, struct passwd * pw, const char *term,
2051 const char *display, const char *auth_proto,
2052 const char *auth_data)
2056 const char *hostname;
2057 time_t last_login_time;
2058 char buf[100], *time_string;
2063 struct sockaddr_storage from;
2065 struct pty_cleanup_context cleanup_context;
2067 /* Get remote host name. */
2068 hostname = get_canonical_hostname();
2071 * Get the time when the user last logged in. Buf will be set to
2072 * contain the hostname the last login was from.
2074 if (!options.use_login) {
2075 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
2078 setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1);
2081 do_pam_session(pw->pw_name, ttyname);
2083 #endif /* USE_PAM */
2085 /* Fork the child. */
2086 if ((pid = fork()) == 0) {
2089 /* Child. Reinitialize the log because the pid has
2091 log_init(av0, options.log_level, options.log_facility, log_stderr);
2093 /* Close the master side of the pseudo tty. */
2096 /* Make the pseudo tty our controlling tty. */
2097 pty_make_controlling_tty(&ttyfd, ttyname);
2099 /* Redirect stdin from the pseudo tty. */
2100 if (dup2(ttyfd, fileno(stdin)) < 0)
2101 error("dup2 stdin failed: %.100s", strerror(errno));
2103 /* Redirect stdout to the pseudo tty. */
2104 if (dup2(ttyfd, fileno(stdout)) < 0)
2105 error("dup2 stdin failed: %.100s", strerror(errno));
2107 /* Redirect stderr to the pseudo tty. */
2108 if (dup2(ttyfd, fileno(stderr)) < 0)
2109 error("dup2 stdin failed: %.100s", strerror(errno));
2111 /* Close the extra descriptor for the pseudo tty. */
2115 * Get IP address of client. This is needed because we want
2116 * to record where the user logged in from. If the
2117 * connection is not a socket, let the ip address be 0.0.0.0.
2119 memset(&from, 0, sizeof(from));
2120 if (packet_get_connection_in() == packet_get_connection_out()) {
2121 fromlen = sizeof(from);
2122 if (getpeername(packet_get_connection_in(),
2123 (struct sockaddr *) & from, &fromlen) < 0) {
2124 debug("getpeername: %.100s", strerror(errno));
2128 /* Record that there was a login on that terminal. */
2129 record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname,
2130 (struct sockaddr *)&from);
2132 /* Check if .hushlogin exists. */
2133 snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir);
2134 quiet_login = stat(line, &st) >= 0;
2138 print_pam_messages();
2139 #endif /* USE_PAM */
2142 * If the user has logged in before, display the time of last
2143 * login. However, don't display anything extra if a command
2144 * has been specified (so that ssh can be used to execute
2145 * commands on a remote machine without users knowing they
2146 * are going to another machine). Login(1) will do this for
2147 * us as well, so check if login(1) is used
2149 if (command == NULL && last_login_time != 0 && !quiet_login &&
2150 !options.use_login) {
2151 /* Convert the date to a string. */
2152 time_string = ctime(&last_login_time);
2153 /* Remove the trailing newline. */
2154 if (strchr(time_string, '\n'))
2155 *strchr(time_string, '\n') = 0;
2156 /* Display the last login time. Host if displayed
2158 if (strcmp(buf, "") == 0)
2159 printf("Last login: %s\r\n", time_string);
2161 printf("Last login: %s from %s\r\n", time_string, buf);
2164 * Print /etc/motd unless a command was specified or printing
2165 * it was disabled in server options or login(1) will be
2166 * used. Note that some machines appear to print it in
2167 * /etc/profile or similar.
2169 if (command == NULL && options.print_motd && !quiet_login &&
2170 !options.use_login) {
2171 /* Print /etc/motd if it exists. */
2172 f = fopen("/etc/motd", "r");
2174 while (fgets(line, sizeof(line), f))
2175 fputs(line, stdout);
2179 /* Do common processing for the child, such as execing the command. */
2180 do_child(command, pw, term, display, auth_proto, auth_data, ttyname);
2184 packet_disconnect("fork failed: %.100s", strerror(errno));
2185 /* Parent. Close the slave side of the pseudo tty. */
2189 * Add a cleanup function to clear the utmp entry and record logout
2190 * time in case we call fatal() (e.g., the connection gets closed).
2192 cleanup_context.pid = pid;
2193 cleanup_context.ttyname = ttyname;
2194 fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
2195 fatal_remove_cleanup(pty_release_proc, (void *) ttyname);
2198 * Create another descriptor of the pty master side for use as the
2199 * standard input. We could use the original descriptor, but this
2200 * simplifies code in server_loop. The descriptor is bidirectional.
2204 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
2206 /* we keep a reference to the pty master */
2207 ptymaster = dup(ptyfd);
2209 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
2211 /* Enter interactive session. */
2212 server_loop(pid, ptyfd, fdout, -1);
2213 /* server_loop _has_ closed ptyfd and fdout. */
2215 /* Cancel the cleanup function. */
2216 fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
2218 /* Record that the user has logged out. */
2219 record_logout(pid, ttyname);
2221 /* Release the pseudo-tty. */
2222 pty_release(ttyname);
2225 * Close the server side of the socket pairs. We must do this after
2226 * the pty cleanup, so that another process doesn't get this pty
2227 * while we're still cleaning up.
2229 if (close(ptymaster) < 0)
2230 error("close(ptymaster): %s", strerror(errno));
2234 * Sets the value of the given variable in the environment. If the variable
2235 * already exists, its value is overriden.
2238 child_set_env(char ***envp, unsigned int *envsizep, const char *name,
2241 unsigned int i, namelen;
2245 * Find the slot where the value should be stored. If the variable
2246 * already exists, we reuse the slot; otherwise we append a new slot
2247 * at the end of the array, expanding if necessary.
2250 namelen = strlen(name);
2251 for (i = 0; env[i]; i++)
2252 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
2255 /* Reuse the slot. */
2258 /* New variable. Expand if necessary. */
2259 if (i >= (*envsizep) - 1) {
2261 env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
2263 /* Need to set the NULL pointer at end of array beyond the new slot. */
2267 /* Allocate space and format the variable in the appropriate slot. */
2268 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
2269 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
2273 * Reads environment variables from the given file and adds/overrides them
2274 * into the environment. If the file does not exist, this does nothing.
2275 * Otherwise, it must consist of empty lines, comments (line starts with '#')
2276 * and assignments of the form name=value. No other forms are allowed.
2279 read_environment_file(char ***env, unsigned int *envsize,
2280 const char *filename)
2286 f = fopen(filename, "r");
2290 while (fgets(buf, sizeof(buf), f)) {
2291 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
2293 if (!*cp || *cp == '#' || *cp == '\n')
2295 if (strchr(cp, '\n'))
2296 *strchr(cp, '\n') = '\0';
2297 value = strchr(cp, '=');
2298 if (value == NULL) {
2299 fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
2302 /* Replace the equals sign by nul, and advance value to the value string. */
2305 child_set_env(env, envsize, cp, value);
2312 * Sets any environment variables which have been specified by PAM
2314 void do_pam_environment(char ***env, int *envsize)
2316 char *equals, var_name[512], var_val[512];
2320 if ((pam_env = fetch_pam_environment()) == NULL)
2323 for(i = 0; pam_env[i] != NULL; i++) {
2324 if ((equals = strstr(pam_env[i], "=")) == NULL)
2327 if (strlen(pam_env[i]) < (sizeof(var_name) - 1))
2329 memset(var_name, '\0', sizeof(var_name));
2330 memset(var_val, '\0', sizeof(var_val));
2332 strncpy(var_name, pam_env[i], equals - pam_env[i]);
2333 strcpy(var_val, equals + 1);
2335 debug("PAM environment: %s=%s", var_name, var_val);
2337 child_set_env(env, envsize, var_name, var_val);
2341 #endif /* USE_PAM */
2344 * Performs common processing for the child, such as setting up the
2345 * environment, closing extra file descriptors, setting the user and group
2346 * ids, and executing the command or shell.
2349 do_child(const char *command, struct passwd * pw, const char *term,
2350 const char *display, const char *auth_proto,
2351 const char *auth_data, const char *ttyname)
2353 const char *shell, *cp = NULL;
2356 unsigned int envsize, i;
2358 extern char **environ;
2362 #ifndef USE_PAM /* pam_nologin handles this */
2363 /* Check /etc/nologin. */
2364 f = fopen("/etc/nologin", "r");
2366 /* /etc/nologin exists. Print its contents and exit. */
2367 while (fgets(buf, sizeof(buf), f))
2370 if (pw->pw_uid != 0)
2373 #endif /* USE_PAM */
2375 /* Set login name in the kernel. */
2376 if (setlogin(pw->pw_name) < 0)
2377 error("setlogin failed: %s", strerror(errno));
2379 /* Set uid, gid, and groups. */
2380 /* Login(1) does this as well, and it needs uid 0 for the "-h"
2381 switch, so we let login(1) to this for us. */
2382 if (!options.use_login) {
2383 if (getuid() == 0 || geteuid() == 0) {
2384 if (setgid(pw->pw_gid) < 0) {
2388 /* Initialize the group list. */
2389 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
2390 perror("initgroups");
2395 /* Permanently switch to the desired uid. */
2396 permanently_set_uid(pw->pw_uid);
2398 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
2399 fatal("Failed to set uids to %d.", (int) pw->pw_uid);
2402 * Get the shell from the password data. An empty shell field is
2403 * legal, and means /bin/sh.
2405 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
2408 /* Try to get AFS tokens for the local cell. */
2412 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
2413 krb_afslog(cell, 0);
2419 /* Initialize the environment. */
2421 env = xmalloc(envsize * sizeof(char *));
2424 if (!options.use_login) {
2425 /* Set basic environment. */
2426 child_set_env(&env, &envsize, "USER", pw->pw_name);
2427 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
2428 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
2429 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
2431 snprintf(buf, sizeof buf, "%.200s/%.50s",
2432 _PATH_MAILDIR, pw->pw_name);
2433 child_set_env(&env, &envsize, "MAIL", buf);
2435 /* Normal systems set SHELL by default. */
2436 child_set_env(&env, &envsize, "SHELL", shell);
2439 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
2441 /* Set custom environment options from RSA authentication. */
2442 while (custom_environment) {
2443 struct envstring *ce = custom_environment;
2446 for (i = 0; s[i] != '=' && s[i]; i++);
2449 child_set_env(&env, &envsize, s, s + i + 1);
2451 custom_environment = ce->next;
2456 snprintf(buf, sizeof buf, "%.50s %d %d",
2457 get_remote_ipaddr(), get_remote_port(), get_local_port());
2458 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
2461 child_set_env(&env, &envsize, "SSH_TTY", ttyname);
2463 child_set_env(&env, &envsize, "TERM", term);
2465 child_set_env(&env, &envsize, "DISPLAY", display);
2469 char *authstate,*krb5cc;
2471 if ((authstate = getenv("AUTHSTATE")) != NULL)
2472 child_set_env(&env,&envsize,"AUTHSTATE",authstate);
2474 if ((krb5cc = getenv("KRB5CCNAME")) != NULL)
2475 child_set_env(&env,&envsize,"KRB5CCNAME",krb5cc);
2481 extern char *ticket;
2484 child_set_env(&env, &envsize, "KRBTKFILE", ticket);
2489 /* Pull in any environment variables that may have been set by PAM. */
2490 do_pam_environment(&env, &envsize);
2491 #endif /* USE_PAM */
2494 child_set_env(&env, &envsize, "XAUTHORITY", xauthfile);
2496 if (auth_get_socket_name() != NULL)
2497 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
2498 auth_get_socket_name());
2500 read_environment_file(&env,&envsize,"/etc/environment");
2502 /* read $HOME/.ssh/environment. */
2503 if (!options.use_login) {
2504 snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir);
2505 read_environment_file(&env, &envsize, buf);
2508 /* dump the environment */
2509 fprintf(stderr, "Environment:\n");
2510 for (i = 0; env[i]; i++)
2511 fprintf(stderr, " %.200s\n", env[i]);
2514 * Close the connection descriptors; note that this is the child, and
2515 * the server will still have the socket open, and it is important
2516 * that we do not shutdown it. Note that the descriptors cannot be
2517 * closed before building the environment, as we call
2518 * get_remote_ipaddr there.
2520 if (packet_get_connection_in() == packet_get_connection_out())
2521 close(packet_get_connection_in());
2523 close(packet_get_connection_in());
2524 close(packet_get_connection_out());
2527 * Close all descriptors related to channels. They will still remain
2528 * open in the parent.
2530 /* XXX better use close-on-exec? -markus */
2531 channel_close_all();
2534 * Close any extra file descriptors. Note that there may still be
2535 * descriptors left by system functions. They will be closed later.
2540 * Close any extra open file descriptors so that we don\'t have them
2541 * hanging around in clients. Note that we want to do this after
2542 * initgroups, because at least on Solaris 2.3 it leaves file
2545 for (i = 3; i < 64; i++)
2548 /* Change current directory to the user\'s home directory. */
2549 if (chdir(pw->pw_dir) < 0)
2550 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
2551 pw->pw_dir, strerror(errno));
2554 * Must take new environment into use so that .ssh/rc, /etc/sshrc and
2555 * xauth are run in the proper environment.
2560 * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
2563 if (!options.use_login) {
2564 if (stat(SSH_USER_RC, &st) >= 0) {
2566 fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC);
2568 f = popen("/bin/sh " SSH_USER_RC, "w");
2570 if (auth_proto != NULL && auth_data != NULL)
2571 fprintf(f, "%s %s\n", auth_proto, auth_data);
2574 fprintf(stderr, "Could not run %s\n", SSH_USER_RC);
2575 } else if (stat(SSH_SYSTEM_RC, &st) >= 0) {
2577 fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC);
2579 f = popen("/bin/sh " SSH_SYSTEM_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_SYSTEM_RC);
2589 /* Add authority data to .Xauthority if appropriate. */
2590 if (auth_proto != NULL && auth_data != NULL) {
2592 fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n",
2593 XAUTH_PATH, display, auth_proto, auth_data);
2595 f = popen(XAUTH_PATH " -q -", "w");
2597 fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data);
2600 fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH);
2603 #endif /* XAUTH_PATH */
2605 /* Get the last component of the shell name. */
2606 cp = strrchr(shell, '/');
2613 * If we have no command, execute the shell. In this case, the shell
2614 * name to be passed in argv[0] is preceded by '-' to indicate that
2615 * this is a login shell.
2618 if (!options.use_login) {
2622 * Check for mail if we have a tty and it was enabled
2623 * in server options.
2625 if (ttyname && options.check_mail) {
2627 struct stat mailstat;
2628 mailbox = getenv("MAIL");
2629 if (mailbox != NULL) {
2630 if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0)
2631 printf("No mail.\n");
2632 else if (mailstat.st_mtime < mailstat.st_atime)
2633 printf("You have mail.\n");
2635 printf("You have new mail.\n");
2638 /* Start the shell. Set initial character to '-'. */
2640 strncpy(buf + 1, cp, sizeof(buf) - 1);
2641 buf[sizeof(buf) - 1] = 0;
2643 /* Execute the shell. */
2646 execve(shell, argv, env);
2648 /* Executing the shell failed. */
2653 /* Launch login(1). */
2655 execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(),
2656 "-p", "-f", "--", pw->pw_name, NULL);
2658 /* Login couldn't be executed, die. */
2665 * Execute the command using the user's shell. This uses the -c
2666 * option to execute the command.
2668 argv[0] = (char *) cp;
2670 argv[2] = (char *) command;
2672 execve(shell, argv, env);