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 1.80 2000/01/20 15:19:22 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 * Close all listening sockets
154 close_listen_socks(void)
157 for (i = 0; i < num_listen_socks; i++)
158 close(listen_socks[i]);
159 num_listen_socks = -1;
163 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
164 * the effect is to reread the configuration file (and to regenerate
168 sighup_handler(int sig)
171 signal(SIGHUP, sighup_handler);
175 * Called from the main program after receiving SIGHUP.
176 * Restarts the server.
181 log("Received SIGHUP; restarting.");
182 close_listen_socks();
183 execv(saved_argv[0], saved_argv);
184 log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno));
189 * Generic signal handler for terminating signals in the master daemon.
190 * These close the listen socket; not closing it seems to cause "Address
191 * already in use" problems on some machines, which is inconvenient.
194 sigterm_handler(int sig)
196 log("Received signal %d; terminating.", sig);
197 close_listen_socks();
202 * SIGCHLD handler. This is called whenever a child dies. This will then
203 * reap any zombies left by exited c.
206 main_sigchld_handler(int sig)
208 int save_errno = errno;
211 while (waitpid(-1, &status, WNOHANG) > 0)
214 signal(SIGCHLD, main_sigchld_handler);
219 * Signal handler for the alarm after the login grace period has expired.
222 grace_alarm_handler(int sig)
224 /* Close the connection. */
227 /* Log error and exit. */
228 fatal("Timeout before authentication for %s.", get_remote_ipaddr());
232 * convert ssh auth msg type into description
235 get_authname(int type)
238 case SSH_CMSG_AUTH_PASSWORD:
240 case SSH_CMSG_AUTH_RSA:
242 case SSH_CMSG_AUTH_RHOSTS_RSA:
244 case SSH_CMSG_AUTH_RHOSTS:
247 case SSH_CMSG_AUTH_KERBEROS:
251 case SSH_CMSG_AUTH_TIS_RESPONSE:
255 fatal("get_authname: unknown auth %d: internal error", type);
260 * Signal handler for the key regeneration alarm. Note that this
261 * alarm only occurs in the daemon waiting for connections, and it does not
262 * do anything with the private key or random state before forking.
263 * Thus there should be no concurrency control/asynchronous execution
267 key_regeneration_alarm(int sig)
269 int save_errno = errno;
271 /* Check if we should generate a new key. */
273 /* This should really be done in the background. */
274 log("Generating new %d bit RSA key.", options.server_key_bits);
276 if (sensitive_data.private_key != NULL)
277 RSA_free(sensitive_data.private_key);
278 sensitive_data.private_key = RSA_new();
280 if (public_key != NULL)
281 RSA_free(public_key);
282 public_key = RSA_new();
284 rsa_generate_key(sensitive_data.private_key, public_key,
285 options.server_key_bits);
288 log("RSA key generation complete.");
290 /* Reschedule the alarm. */
291 signal(SIGALRM, key_regeneration_alarm);
292 alarm(options.key_regeneration_time);
297 * Main program for the daemon.
300 main(int ac, char **av)
304 int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1;
306 int remote_major, remote_minor;
309 struct sockaddr_storage from;
310 char buf[100]; /* Must not be larger than remote_version. */
311 char remote_version[100]; /* Must be at least as big as buf. */
312 const char *remote_ip;
316 struct linger linger;
318 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
319 int listen_sock, maxfd;
323 if (strchr(av[0], '/'))
324 av0 = strrchr(av[0], '/') + 1;
328 /* Initialize configuration options to their default values. */
329 initialize_server_options(&options);
331 /* Parse command-line arguments. */
332 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ46")) != EOF) {
341 config_file_name = optarg;
345 options.log_level = SYSLOG_LEVEL_DEBUG;
354 options.log_level = SYSLOG_LEVEL_QUIET;
357 options.server_key_bits = atoi(optarg);
360 options.ports_from_cmdline = 1;
361 if (options.num_ports >= MAX_PORTS)
362 fatal("too many ports.\n");
363 options.ports[options.num_ports++] = atoi(optarg);
366 options.login_grace_time = atoi(optarg);
369 options.key_regeneration_time = atoi(optarg);
372 options.host_key_file = optarg;
375 client_version_string = optarg;
376 /* only makes sense with inetd_flag, i.e. no listen() */
381 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
382 fprintf(stderr, "Usage: %s [options]\n", av0);
383 fprintf(stderr, "Options:\n");
384 fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE);
385 fprintf(stderr, " -d Debugging mode\n");
386 fprintf(stderr, " -i Started from inetd\n");
387 fprintf(stderr, " -q Quiet (no logging)\n");
388 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
389 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
390 fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n");
391 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
392 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
394 fprintf(stderr, " -4 Use IPv4 only\n");
395 fprintf(stderr, " -6 Use IPv6 only\n");
401 * Force logging to stderr until we have loaded the private host
402 * key (unless started from inetd)
405 options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
406 options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
409 /* check if RSA support exists */
410 if (rsa_alive() == 0) {
412 printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n");
413 log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)");
416 /* Read server configuration options from the configuration file. */
417 read_server_config(&options, config_file_name);
419 /* Fill in default values for those options not explicitly set. */
420 fill_default_server_options(&options);
422 /* Check certain values for sanity. */
423 if (options.server_key_bits < 512 ||
424 options.server_key_bits > 32768) {
425 fprintf(stderr, "Bad server key size.\n");
428 /* Check that there are no remaining arguments. */
430 fprintf(stderr, "Extra argument %s.\n", av[optind]);
434 debug("sshd version %.100s", SSH_VERSION);
436 sensitive_data.host_key = RSA_new();
438 /* Load the host key. It must have empty passphrase. */
439 if (!load_private_key(options.host_key_file, "",
440 sensitive_data.host_key, &comment)) {
441 error("Could not load host key: %.200s: %.100s",
442 options.host_key_file, strerror(errno));
447 /* Initialize the log (it is reinitialized below in case we
449 if (debug_flag && !inetd_flag)
451 log_init(av0, options.log_level, options.log_facility, log_stderr);
453 /* If not in debugging mode, and not started from inetd,
454 disconnect from the controlling terminal, and fork. The
455 original process exits. */
456 if (!debug_flag && !inetd_flag) {
459 #endif /* TIOCNOTTY */
460 if (daemon(0, 0) < 0)
461 fatal("daemon() failed: %.200s", strerror(errno));
463 /* Disconnect from the controlling tty. */
465 fd = open("/dev/tty", O_RDWR | O_NOCTTY);
467 (void) ioctl(fd, TIOCNOTTY, NULL);
470 #endif /* TIOCNOTTY */
472 /* Reinitialize the log (because of the fork above). */
473 log_init(av0, options.log_level, options.log_facility, log_stderr);
475 /* Check that server and host key lengths differ sufficiently.
476 This is necessary to make double encryption work with rsaref.
477 Oh, I hate software patents. I dont know if this can go? Niels */
478 if (options.server_key_bits >
479 BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
480 options.server_key_bits <
481 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
482 options.server_key_bits =
483 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
484 debug("Forcing server key to %d bits to make it differ from host key.",
485 options.server_key_bits);
487 /* Do not display messages to stdout in RSA code. */
490 /* Initialize the random number generator. */
493 /* Chdir to the root directory so that the current disk can be
494 unmounted if desired. */
497 /* Close connection cleanly after attack. */
498 cipher_attack_detected = packet_disconnect;
500 /* Start listening for a socket, unless started from inetd. */
503 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
507 /* We intentionally do not close the descriptors 0, 1, and 2
508 as our code for setting the descriptors won\'t work
509 if ttyfd happens to be one of those. */
510 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
512 public_key = RSA_new();
513 sensitive_data.private_key = RSA_new();
515 log("Generating %d bit RSA key.", options.server_key_bits);
516 rsa_generate_key(sensitive_data.private_key, public_key,
517 options.server_key_bits);
519 log("RSA key generation complete.");
521 for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
522 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
524 if (num_listen_socks >= MAX_LISTEN_SOCKS)
525 fatal("Too many listen sockets. "
526 "Enlarge MAX_LISTEN_SOCKS");
527 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
528 ntop, sizeof(ntop), strport, sizeof(strport),
529 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
530 error("getnameinfo failed");
533 /* Create socket for listening. */
534 listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
535 if (listen_sock < 0) {
536 /* kernel may not support ipv6 */
537 verbose("socket: %.100s", strerror(errno));
540 if (fcntl(listen_sock, F_SETFL, O_NONBLOCK) < 0) {
541 error("listen_sock O_NONBLOCK: %s", strerror(errno));
546 * Set socket options. We try to make the port
547 * reusable and have it close as fast as possible
548 * without waiting in unnecessary wait states on
551 setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
552 (void *) &on, sizeof(on));
555 setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
556 (void *) &linger, sizeof(linger));
558 debug("Bind to port %s on %s.", strport, ntop);
560 /* Bind the socket to the desired port. */
561 if ((bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) &&
563 error("Bind to port %s on %s failed: %.200s.",
564 strport, ntop, strerror(errno));
568 listen_socks[num_listen_socks] = listen_sock;
571 /* Start listening on the port. */
572 log("Server listening on %s port %s.", ntop, strport);
573 if (listen(listen_sock, 5) < 0)
574 fatal("listen: %.100s", strerror(errno));
577 freeaddrinfo(options.listen_addrs);
579 if (!num_listen_socks)
580 fatal("Cannot bind any address.");
584 * Record our pid in /etc/sshd_pid to make it easier
585 * to kill the correct sshd. We don\'t want to do
586 * this before the bind above because the bind will
587 * fail if there already is a daemon, and this will
588 * overwrite any old pid in the file.
590 f = fopen(SSH_DAEMON_PID_FILE, "w");
592 fprintf(f, "%u\n", (unsigned int) getpid());
597 public_key = RSA_new();
598 sensitive_data.private_key = RSA_new();
600 log("Generating %d bit RSA key.", options.server_key_bits);
601 rsa_generate_key(sensitive_data.private_key, public_key,
602 options.server_key_bits);
604 log("RSA key generation complete.");
606 /* Schedule server key regeneration alarm. */
607 signal(SIGALRM, key_regeneration_alarm);
608 alarm(options.key_regeneration_time);
610 /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
611 signal(SIGHUP, sighup_handler);
612 signal(SIGTERM, sigterm_handler);
613 signal(SIGQUIT, sigterm_handler);
615 /* Arrange SIGCHLD to be caught. */
616 signal(SIGCHLD, main_sigchld_handler);
618 /* setup fd set for listen */
620 for (i = 0; i < num_listen_socks; i++)
621 if (listen_socks[i] > maxfd)
622 maxfd = listen_socks[i];
623 fdsetsz = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
624 fdset = (fd_set *)xmalloc(fdsetsz);
627 * Stay listening for connections until the system crashes or
628 * the daemon is killed with a signal.
633 /* Wait in select until there is a connection. */
634 memset(fdset, 0, fdsetsz);
635 for (i = 0; i < num_listen_socks; i++)
636 FD_SET(listen_socks[i], fdset);
637 if (select(maxfd + 1, fdset, NULL, NULL, NULL) < 0) {
639 error("select: %.100s", strerror(errno));
642 for (i = 0; i < num_listen_socks; i++) {
643 if (!FD_ISSET(listen_socks[i], fdset))
645 fromlen = sizeof(from);
646 newsock = accept(listen_socks[i], (struct sockaddr *)&from,
649 if (errno != EINTR && errno != EWOULDBLOCK)
650 error("accept: %.100s", strerror(errno));
653 if (fcntl(newsock, F_SETFL, 0) < 0) {
654 error("newsock del O_NONBLOCK: %s", strerror(errno));
658 * Got connection. Fork a child to handle it, unless
659 * we are in debugging mode.
663 * In debugging mode. Close the listening
664 * socket, and start processing the
665 * connection without forking.
667 debug("Server will not fork when running in debugging mode.");
668 close_listen_socks();
675 * Normal production daemon. Fork, and have
676 * the child process the connection. The
677 * parent continues listening.
679 if ((pid = fork()) == 0) {
681 * Child. Close the listening socket, and start using the
682 * accepted socket. Reinitialize logging (since our pid has
683 * changed). We break out of the loop to handle the connection.
685 close_listen_socks();
688 log_init(av0, options.log_level, options.log_facility, log_stderr);
693 /* Parent. Stay in the loop. */
695 error("fork: %.100s", strerror(errno));
697 debug("Forked child %d.", pid);
699 /* Mark that the key has been used (it was "given" to the child). */
704 /* Close the new socket (the child is now taking care of it). */
706 } /* for (i = 0; i < num_listen_socks; i++) */
707 /* child process check (or debug mode) */
708 if (num_listen_socks < 0)
713 /* This is the child processing a new connection. */
716 * Disable the key regeneration alarm. We will not regenerate the
717 * key since we are no longer in a position to give it to anyone. We
718 * will not restart on SIGHUP since it no longer makes sense.
721 signal(SIGALRM, SIG_DFL);
722 signal(SIGHUP, SIG_DFL);
723 signal(SIGTERM, SIG_DFL);
724 signal(SIGQUIT, SIG_DFL);
725 signal(SIGCHLD, SIG_DFL);
728 * Set socket options for the connection. We want the socket to
729 * close as fast as possible without waiting for anything. If the
730 * connection is not a socket, these will do nothing.
732 /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
735 setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
738 * Register our connection. This turns encryption off because we do
741 packet_set_connection(sock_in, sock_out);
743 remote_port = get_remote_port();
744 remote_ip = get_remote_ipaddr();
746 /* Check whether logins are denied from this host. */
748 /* XXX LIBWRAP noes not know about IPv6 */
750 struct request_info req;
752 request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL);
755 if (!hosts_access(&req)) {
760 /*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
763 /* Log the connection. */
764 verbose("Connection from %.500s port %d", remote_ip, remote_port);
767 * We don\'t want to listen forever unless the other side
768 * successfully authenticates itself. So we set up an alarm which is
769 * cleared after successful authentication. A limit of zero
770 * indicates no limit. Note that we don\'t set the alarm in debugging
771 * mode; it is just annoying to have the server exit just when you
772 * are about to discover the bug.
774 signal(SIGALRM, grace_alarm_handler);
776 alarm(options.login_grace_time);
778 if (client_version_string != NULL) {
779 /* we are exec'ed by sshd2, so skip exchange of protocol version */
780 strlcpy(buf, client_version_string, sizeof(buf));
782 /* Send our protocol version identification. */
783 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
784 PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
785 if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) {
786 log("Could not write ident string to %s.", remote_ip);
790 /* Read other side\'s version identification. */
791 for (i = 0; i < sizeof(buf) - 1; i++) {
792 if (read(sock_in, &buf[i], 1) != 1) {
793 log("Did not receive ident string from %s.", remote_ip);
796 if (buf[i] == '\r') {
801 if (buf[i] == '\n') {
807 buf[sizeof(buf) - 1] = 0;
811 * Check that the versions match. In future this might accept
812 * several versions and set appropriate flags to handle them.
814 if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor,
815 remote_version) != 3) {
816 char *s = "Protocol mismatch.\n";
818 (void) atomicio(write, sock_out, s, strlen(s));
821 log("Bad protocol version identification '%.100s' from %s",
825 debug("Client protocol version %d.%d; client software version %.100s",
826 remote_major, remote_minor, remote_version);
827 if (remote_major != PROTOCOL_MAJOR) {
828 char *s = "Protocol major versions differ.\n";
830 (void) atomicio(write, sock_out, s, strlen(s));
833 log("Protocol major versions differ for %s: %d vs. %d",
834 remote_ip, PROTOCOL_MAJOR, remote_major);
837 /* Check that the client has sufficiently high software version. */
838 if (remote_major == 1 && remote_minor < 3)
839 packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version.");
841 if (remote_major == 1 && remote_minor == 3) {
842 /* note that this disables agent-forwarding */
846 * Check that the connection comes from a privileged port. Rhosts-
847 * and Rhosts-RSA-Authentication only make sense from priviledged
848 * programs. Of course, if the intruder has root access on his local
849 * machine, he can connect from any port. So do not use these
850 * authentication methods from machines that you do not trust.
852 if (remote_port >= IPPORT_RESERVED ||
853 remote_port < IPPORT_RESERVED / 2) {
854 options.rhosts_authentication = 0;
855 options.rhosts_rsa_authentication = 0;
858 if (!packet_connection_is_ipv4() &&
859 options.kerberos_authentication) {
860 debug("Kerberos Authentication disabled, only available for IPv4.");
861 options.kerberos_authentication = 0;
865 packet_set_nonblocking();
867 /* perform the key exchange */
870 /* authenticate user and start session */
874 /* Cleanup user's ticket cache file. */
875 if (options.kerberos_ticket_cleanup)
879 /* Cleanup user's local Xauthority file. */
883 /* The connection has been terminated. */
884 verbose("Closing connection to %.100s", remote_ip);
902 BIGNUM *session_key_int;
903 unsigned char session_key[SSH_SESSION_KEY_LENGTH];
904 unsigned char cookie[8];
905 unsigned int cipher_type, auth_mask, protocol_flags;
909 * Generate check bytes that the client must send back in the user
910 * packet in order for it to be accepted; this is used to defy ip
911 * spoofing attacks. Note that this only works against somebody
912 * doing IP spoofing from a remote machine; any machine on the local
913 * network can still see outgoing packets and catch the random
914 * cookie. This only affects rhosts authentication, and this is one
915 * of the reasons why it is inherently insecure.
917 for (i = 0; i < 8; i++) {
920 cookie[i] = rand & 0xff;
925 * Send our public key. We include in the packet 64 bits of random
926 * data that must be matched in the reply in order to prevent IP
929 packet_start(SSH_SMSG_PUBLIC_KEY);
930 for (i = 0; i < 8; i++)
931 packet_put_char(cookie[i]);
933 /* Store our public server RSA key. */
934 packet_put_int(BN_num_bits(public_key->n));
935 packet_put_bignum(public_key->e);
936 packet_put_bignum(public_key->n);
938 /* Store our public host RSA key. */
939 packet_put_int(BN_num_bits(sensitive_data.host_key->n));
940 packet_put_bignum(sensitive_data.host_key->e);
941 packet_put_bignum(sensitive_data.host_key->n);
943 /* Put protocol flags. */
944 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
946 /* Declare which ciphers we support. */
947 packet_put_int(cipher_mask());
949 /* Declare supported authentication types. */
951 if (options.rhosts_authentication)
952 auth_mask |= 1 << SSH_AUTH_RHOSTS;
953 if (options.rhosts_rsa_authentication)
954 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
955 if (options.rsa_authentication)
956 auth_mask |= 1 << SSH_AUTH_RSA;
958 if (options.kerberos_authentication)
959 auth_mask |= 1 << SSH_AUTH_KERBEROS;
962 if (options.kerberos_tgt_passing)
963 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
964 if (options.afs_token_passing)
965 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
968 if (options.skey_authentication == 1)
969 auth_mask |= 1 << SSH_AUTH_TIS;
971 if (options.password_authentication)
972 auth_mask |= 1 << SSH_AUTH_PASSWORD;
973 packet_put_int(auth_mask);
975 /* Send the packet and wait for it to be sent. */
979 debug("Sent %d bit public key and %d bit host key.",
980 BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n));
982 /* Read clients reply (cipher type and session key). */
983 packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
985 /* Get cipher type and check whether we accept this. */
986 cipher_type = packet_get_char();
988 if (!(cipher_mask() & (1 << cipher_type)))
989 packet_disconnect("Warning: client selects unsupported cipher.");
991 /* Get check bytes from the packet. These must match those we
992 sent earlier with the public key packet. */
993 for (i = 0; i < 8; i++)
994 if (cookie[i] != packet_get_char())
995 packet_disconnect("IP Spoofing check bytes do not match.");
997 debug("Encryption type: %.200s", cipher_name(cipher_type));
999 /* Get the encrypted integer. */
1000 session_key_int = BN_new();
1001 packet_get_bignum(session_key_int, &slen);
1003 protocol_flags = packet_get_int();
1004 packet_set_protocol_flags(protocol_flags);
1006 packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
1009 * Decrypt it using our private server key and private host key (key
1010 * with larger modulus first).
1012 if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) {
1013 /* Private key has bigger modulus. */
1014 if (BN_num_bits(sensitive_data.private_key->n) <
1015 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
1016 fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1017 get_remote_ipaddr(),
1018 BN_num_bits(sensitive_data.private_key->n),
1019 BN_num_bits(sensitive_data.host_key->n),
1020 SSH_KEY_BITS_RESERVED);
1022 rsa_private_decrypt(session_key_int, session_key_int,
1023 sensitive_data.private_key);
1024 rsa_private_decrypt(session_key_int, session_key_int,
1025 sensitive_data.host_key);
1027 /* Host key has bigger modulus (or they are equal). */
1028 if (BN_num_bits(sensitive_data.host_key->n) <
1029 BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) {
1030 fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d",
1031 get_remote_ipaddr(),
1032 BN_num_bits(sensitive_data.host_key->n),
1033 BN_num_bits(sensitive_data.private_key->n),
1034 SSH_KEY_BITS_RESERVED);
1036 rsa_private_decrypt(session_key_int, session_key_int,
1037 sensitive_data.host_key);
1038 rsa_private_decrypt(session_key_int, session_key_int,
1039 sensitive_data.private_key);
1042 compute_session_id(session_id, cookie,
1043 sensitive_data.host_key->n,
1044 sensitive_data.private_key->n);
1046 /* Destroy the private and public keys. They will no longer be needed. */
1047 RSA_free(public_key);
1048 RSA_free(sensitive_data.private_key);
1049 RSA_free(sensitive_data.host_key);
1052 * Extract session key from the decrypted integer. The key is in the
1053 * least significant 256 bits of the integer; the first byte of the
1054 * key is in the highest bits.
1056 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1057 len = BN_num_bytes(session_key_int);
1058 if (len < 0 || len > sizeof(session_key))
1059 fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d",
1060 get_remote_ipaddr(),
1061 len, sizeof(session_key));
1062 memset(session_key, 0, sizeof(session_key));
1063 BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
1065 /* Destroy the decrypted integer. It is no longer needed. */
1066 BN_clear_free(session_key_int);
1068 /* Xor the first 16 bytes of the session key with the session id. */
1069 for (i = 0; i < 16; i++)
1070 session_key[i] ^= session_id[i];
1072 /* Set the session key. From this on all communications will be encrypted. */
1073 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1075 /* Destroy our copy of the session key. It is no longer needed. */
1076 memset(session_key, 0, sizeof(session_key));
1078 debug("Received session key; encryption turned on.");
1080 /* Send an acknowledgement packet. Note that this packet is sent encrypted. */
1081 packet_start(SSH_SMSG_SUCCESS);
1083 packet_write_wait();
1088 * Check if the user is allowed to log in via ssh. If user is listed in
1089 * DenyUsers or user's primary group is listed in DenyGroups, false will
1090 * be returned. If AllowUsers isn't empty and user isn't listed there, or
1091 * if AllowGroups isn't empty and user isn't listed there, false will be
1092 * returned. Otherwise true is returned.
1093 * XXX This function should also check if user has a valid shell
1096 allowed_user(struct passwd * pw)
1100 #ifdef WITH_AIXAUTHENTICATE
1102 #endif /* WITH_AIXAUTHENTICATE */
1104 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
1108 /* XXX Should check for valid login shell */
1110 /* Return false if user is listed in DenyUsers */
1111 if (options.num_deny_users > 0) {
1114 for (i = 0; i < options.num_deny_users; i++)
1115 if (match_pattern(pw->pw_name, options.deny_users[i]))
1118 /* Return false if AllowUsers isn't empty and user isn't listed there */
1119 if (options.num_allow_users > 0) {
1122 for (i = 0; i < options.num_allow_users; i++)
1123 if (match_pattern(pw->pw_name, options.allow_users[i]))
1125 /* i < options.num_allow_users iff we break for loop */
1126 if (i >= options.num_allow_users)
1129 /* Get the primary group name if we need it. Return false if it fails */
1130 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
1131 grp = getgrgid(pw->pw_gid);
1135 /* Return false if user's group is listed in DenyGroups */
1136 if (options.num_deny_groups > 0) {
1139 for (i = 0; i < options.num_deny_groups; i++)
1140 if (match_pattern(grp->gr_name, options.deny_groups[i]))
1144 * Return false if AllowGroups isn't empty and user's group
1145 * isn't listed there
1147 if (options.num_allow_groups > 0) {
1150 for (i = 0; i < options.num_allow_groups; i++)
1151 if (match_pattern(grp->gr_name, options.allow_groups[i]))
1153 /* i < options.num_allow_groups iff we break for
1155 if (i >= options.num_allow_groups)
1160 #ifdef WITH_AIXAUTHENTICATE
1161 if (loginrestrictions(pw->pw_name,S_LOGIN,NULL,&loginmsg) != 0)
1163 #endif /* WITH_AIXAUTHENTICATE */
1165 /* We found no reason not to let this user try to log on... */
1170 * Performs authentication of an incoming connection. Session key has already
1171 * been exchanged and encryption is enabled.
1176 struct passwd *pw, pwcopy;
1180 /* Get the name of the user that we wish to log in as. */
1181 packet_read_expect(&plen, SSH_CMSG_USER);
1183 /* Get the user name. */
1184 user = packet_get_string(&ulen);
1185 packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
1187 setproctitle("%s", user);
1189 #ifdef WITH_AIXAUTHENTICATE
1191 #endif /* WITH_AIXAUTHENTICATE */
1194 /* If machine has AFS, set process authentication group. */
1201 /* Verify that the user is a valid user. */
1202 pw = getpwnam(user);
1203 if (!pw || !allowed_user(pw))
1204 do_fake_authloop(user);
1206 /* Take a copy of the returned structure. */
1207 memset(&pwcopy, 0, sizeof(pwcopy));
1208 pwcopy.pw_name = xstrdup(pw->pw_name);
1209 pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
1210 pwcopy.pw_uid = pw->pw_uid;
1211 pwcopy.pw_gid = pw->pw_gid;
1212 pwcopy.pw_dir = xstrdup(pw->pw_dir);
1213 pwcopy.pw_shell = xstrdup(pw->pw_shell);
1221 * If we are not running as root, the user must have the same uid as
1224 if (getuid() != 0 && pw->pw_uid != getuid())
1225 packet_disconnect("Cannot change user when server not running as root.");
1227 debug("Attempting authentication for %.100s.", user);
1229 /* If the user has no password, accept authentication immediately. */
1230 if (options.password_authentication &&
1232 (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
1235 auth_pam_password(pw, "")) {
1237 auth_password(pw, "")) {
1238 #endif /* USE_PAM */
1239 /* Authentication with empty password succeeded. */
1240 log("Login for user %s from %.100s, accepted without authentication.",
1241 pw->pw_name, get_remote_ipaddr());
1243 /* Loop until the user has been authenticated or the
1244 connection is closed, do_authloop() returns only if
1245 authentication is successfull */
1249 /* Check if the user is logging in as root and root logins are disallowed. */
1250 if (pw->pw_uid == 0 && !options.permit_root_login) {
1252 log("Root login accepted for forced command.");
1254 packet_disconnect("ROOT LOGIN REFUSED FROM %.200s",
1255 get_canonical_hostname());
1257 /* The user has been authenticated and accepted. */
1258 #ifdef WITH_AIXAUTHENTICATE
1259 loginsuccess(user,get_canonical_hostname(),"ssh",&loginmsg);
1260 #endif /* WITH_AIXAUTHENTICATE */
1261 packet_start(SSH_SMSG_SUCCESS);
1263 packet_write_wait();
1265 /* Perform session preparation. */
1266 do_authenticated(pw);
1269 #define AUTH_FAIL_MAX 6
1270 #define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2)
1271 #define AUTH_FAIL_MSG "Too many authentication failures for %.100s"
1274 * read packets and try to authenticate local user *pw.
1275 * return if authentication is successfull
1278 do_authloop(struct passwd * pw)
1282 BIGNUM *client_host_key_e, *client_host_key_n;
1284 char *client_user = NULL, *password = NULL;
1286 int plen, dlen, nlen, ulen, elen;
1288 void (*authlog) (const char *fmt,...) = verbose;
1290 /* Indicate that authentication is needed. */
1291 packet_start(SSH_SMSG_FAILURE);
1293 packet_write_wait();
1295 for (attempt = 1;; attempt++) {
1296 int authenticated = 0;
1297 strlcpy(user, "", sizeof user);
1299 /* Get a packet from the client. */
1300 type = packet_read(&plen);
1302 /* Process the packet. */
1305 case SSH_CMSG_HAVE_KERBEROS_TGT:
1306 if (!options.kerberos_tgt_passing) {
1307 /* packet_get_all(); */
1308 verbose("Kerberos tgt passing disabled.");
1311 /* Accept Kerberos tgt. */
1312 char *tgt = packet_get_string(&dlen);
1313 packet_integrity_check(plen, 4 + dlen, type);
1314 if (!auth_kerberos_tgt(pw, tgt))
1315 verbose("Kerberos tgt REFUSED for %s", pw->pw_name);
1320 case SSH_CMSG_HAVE_AFS_TOKEN:
1321 if (!options.afs_token_passing || !k_hasafs()) {
1322 /* packet_get_all(); */
1323 verbose("AFS token passing disabled.");
1326 /* Accept AFS token. */
1327 char *token_string = packet_get_string(&dlen);
1328 packet_integrity_check(plen, 4 + dlen, type);
1329 if (!auth_afs_token(pw, token_string))
1330 verbose("AFS token REFUSED for %s", pw->pw_name);
1331 xfree(token_string);
1336 case SSH_CMSG_AUTH_KERBEROS:
1337 if (!options.kerberos_authentication) {
1338 /* packet_get_all(); */
1339 verbose("Kerberos authentication disabled.");
1342 /* Try Kerberos v4 authentication. */
1344 char *tkt_user = NULL;
1345 char *kdata = packet_get_string((unsigned int *) &auth.length);
1346 packet_integrity_check(plen, 4 + auth.length, type);
1348 if (auth.length < MAX_KTXT_LEN)
1349 memcpy(auth.dat, kdata, auth.length);
1352 authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
1354 if (authenticated) {
1355 snprintf(user, sizeof user, " tktuser %s", tkt_user);
1362 case SSH_CMSG_AUTH_RHOSTS:
1363 if (!options.rhosts_authentication) {
1364 verbose("Rhosts authentication disabled.");
1368 * Get client user name. Note that we just have to
1369 * trust the client; this is one reason why rhosts
1370 * authentication is insecure. (Another is
1371 * IP-spoofing on a local network.)
1373 client_user = packet_get_string(&ulen);
1374 packet_integrity_check(plen, 4 + ulen, type);
1376 /* Try to authenticate using /etc/hosts.equiv and
1378 authenticated = auth_rhosts(pw, client_user);
1380 snprintf(user, sizeof user, " ruser %s", client_user);
1383 case SSH_CMSG_AUTH_RHOSTS_RSA:
1384 if (!options.rhosts_rsa_authentication) {
1385 verbose("Rhosts with RSA authentication disabled.");
1389 * Get client user name. Note that we just have to
1390 * trust the client; root on the client machine can
1391 * claim to be any user.
1393 client_user = packet_get_string(&ulen);
1395 /* Get the client host key. */
1396 client_host_key_e = BN_new();
1397 client_host_key_n = BN_new();
1398 bits = packet_get_int();
1399 packet_get_bignum(client_host_key_e, &elen);
1400 packet_get_bignum(client_host_key_n, &nlen);
1402 if (bits != BN_num_bits(client_host_key_n))
1403 error("Warning: keysize mismatch for client_host_key: "
1404 "actual %d, announced %d", BN_num_bits(client_host_key_n), bits);
1405 packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
1407 authenticated = auth_rhosts_rsa(pw, client_user,
1408 client_host_key_e, client_host_key_n);
1409 BN_clear_free(client_host_key_e);
1410 BN_clear_free(client_host_key_n);
1412 snprintf(user, sizeof user, " ruser %s", client_user);
1415 case SSH_CMSG_AUTH_RSA:
1416 if (!options.rsa_authentication) {
1417 verbose("RSA authentication disabled.");
1420 /* RSA authentication requested. */
1422 packet_get_bignum(n, &nlen);
1423 packet_integrity_check(plen, nlen, type);
1424 authenticated = auth_rsa(pw, n);
1428 case SSH_CMSG_AUTH_PASSWORD:
1429 if (!options.password_authentication) {
1430 verbose("Password authentication disabled.");
1434 * Read user password. It is in plain text, but was
1435 * transmitted over the encrypted channel so it is
1436 * not visible to an outside observer.
1438 password = packet_get_string(&dlen);
1439 packet_integrity_check(plen, 4 + dlen, type);
1442 /* Do PAM auth with password */
1443 authenticated = auth_pam_password(pw, password);
1445 /* Try authentication with the password. */
1446 authenticated = auth_password(pw, password);
1447 #endif /* USE_PAM */
1448 memset(password, 0, strlen(password));
1453 case SSH_CMSG_AUTH_TIS:
1454 debug("rcvd SSH_CMSG_AUTH_TIS");
1455 if (options.skey_authentication == 1) {
1456 char *skeyinfo = skey_keyinfo(pw->pw_name);
1457 if (skeyinfo == NULL) {
1458 debug("generating fake skeyinfo for %.100s.", pw->pw_name);
1459 skeyinfo = skey_fake_keyinfo(pw->pw_name);
1461 if (skeyinfo != NULL) {
1462 /* we send our s/key- in tis-challenge messages */
1463 debug("sending challenge '%s'", skeyinfo);
1464 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1465 packet_put_string(skeyinfo, strlen(skeyinfo));
1467 packet_write_wait();
1472 case SSH_CMSG_AUTH_TIS_RESPONSE:
1473 debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
1474 if (options.skey_authentication == 1) {
1475 char *response = packet_get_string(&dlen);
1476 debug("skey response == '%s'", response);
1477 packet_integrity_check(plen, 4 + dlen, type);
1478 authenticated = (skey_haskey(pw->pw_name) == 0 &&
1479 skey_passcheck(pw->pw_name, response) != -1);
1484 case SSH_CMSG_AUTH_TIS:
1485 /* TIS Authentication is unsupported */
1486 log("TIS authentication unsupported.");
1492 * Any unknown messages will be ignored (and failure
1493 * returned) during authentication.
1495 log("Unknown message during authentication: type %d", type);
1499 /* Raise logging level */
1500 if (authenticated ||
1501 attempt == AUTH_FAIL_LOG ||
1502 type == SSH_CMSG_AUTH_PASSWORD)
1505 authlog("%s %s for %.200s from %.200s port %d%s",
1506 authenticated ? "Accepted" : "Failed",
1508 pw->pw_uid == 0 ? "ROOT" : pw->pw_name,
1509 get_remote_ipaddr(),
1513 if (authenticated) {
1515 if (!do_pam_account(pw->pw_name, client_user)) {
1516 if (client_user != NULL)
1519 do_fake_authloop(pw->pw_name);
1521 #endif /* USE_PAM */
1525 if (client_user != NULL) {
1530 if (attempt > AUTH_FAIL_MAX)
1531 packet_disconnect(AUTH_FAIL_MSG, pw->pw_name);
1533 /* Send a message indicating that the authentication attempt failed. */
1534 packet_start(SSH_SMSG_FAILURE);
1536 packet_write_wait();
1541 * The user does not exist or access is denied,
1542 * but fake indication that authentication is needed.
1545 do_fake_authloop(char *user)
1549 log("Faking authloop for illegal user %.200s from %.200s port %d",
1551 get_remote_ipaddr(),
1554 /* Indicate that authentication is needed. */
1555 packet_start(SSH_SMSG_FAILURE);
1557 packet_write_wait();
1560 * Keep reading packets, and always respond with a failure. This is
1561 * to avoid disclosing whether such a user really exists.
1563 for (attempt = 1;; attempt++) {
1564 /* Read a packet. This will not return if the client disconnects. */
1567 (void)packet_read(&plen);
1569 int type = packet_read(&plen);
1571 char *password, *skeyinfo;
1572 /* Try to send a fake s/key challenge. */
1573 if (options.skey_authentication == 1 &&
1574 (skeyinfo = skey_fake_keyinfo(user)) != NULL) {
1575 if (type == SSH_CMSG_AUTH_TIS) {
1576 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1577 packet_put_string(skeyinfo, strlen(skeyinfo));
1579 packet_write_wait();
1581 } else if (type == SSH_CMSG_AUTH_PASSWORD &&
1582 options.password_authentication &&
1583 (password = packet_get_string(&dlen)) != NULL &&
1585 strncasecmp(password, "s/key", 5) == 0 ) {
1586 packet_send_debug(skeyinfo);
1590 if (attempt > AUTH_FAIL_MAX)
1591 packet_disconnect(AUTH_FAIL_MSG, user);
1594 * Send failure. This should be indistinguishable from a
1595 * failed authentication.
1597 packet_start(SSH_SMSG_FAILURE);
1599 packet_write_wait();
1600 #ifdef WITH_AIXAUTHENTICATE
1601 if (strncmp(get_authname(type),"password",
1602 strlen(get_authname(type))) == 0)
1603 loginfailed(pw->pw_name,get_canonical_hostname(),"ssh");
1604 #endif /* WITH_AIXAUTHENTICATE */
1612 * Remove local Xauthority file.
1615 xauthfile_cleanup_proc(void *ignore)
1617 debug("xauthfile_cleanup_proc called");
1619 if (xauthfile != NULL) {
1626 struct pty_cleanup_context {
1627 const char *ttyname;
1632 * Function to perform cleanup if we get aborted abnormally (e.g., due to a
1633 * dropped connection).
1636 pty_cleanup_proc(void *context)
1638 struct pty_cleanup_context *cu = context;
1640 debug("pty_cleanup_proc called");
1642 /* Record that the user has logged out. */
1643 record_logout(cu->pid, cu->ttyname);
1645 /* Release the pseudo-tty. */
1646 pty_release(cu->ttyname);
1649 /* simple cleanup: chown tty slave back to root */
1651 pty_release_proc(void *tty)
1653 char *ttyname = tty;
1654 pty_release(ttyname);
1658 * Prepares for an interactive session. This is called after the user has
1659 * been successfully authenticated. During this message exchange, pseudo
1660 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
1661 * are requested, etc.
1664 do_authenticated(struct passwd * pw)
1667 int compression_level = 0, enable_compression_after_reply = 0;
1668 int have_pty = 0, ptyfd = -1, ttyfd = -1, xauthfd = -1;
1669 int row, col, xpixel, ypixel, screen;
1671 char *command, *term = NULL, *display = NULL, *proto = NULL, *data = NULL;
1675 * Cancel the alarm we set to limit the time taken for
1681 * Inform the channel mechanism that we are the server side and that
1682 * the client may request to connect to any port at all. (The user
1683 * could do it anyway, and we wouldn\'t know what is permitted except
1684 * by the client telling us, so we can equally well trust the client
1685 * not to request anything bogus.)
1687 channel_permit_all_opens();
1690 * We stay in this loop until the client requests to execute a shell
1696 /* Get a packet from the client. */
1697 type = packet_read(&plen);
1699 /* Process the packet. */
1701 case SSH_CMSG_REQUEST_COMPRESSION:
1702 packet_integrity_check(plen, 4, type);
1703 compression_level = packet_get_int();
1704 if (compression_level < 1 || compression_level > 9) {
1705 packet_send_debug("Received illegal compression level %d.",
1709 /* Enable compression after we have responded with SUCCESS. */
1710 enable_compression_after_reply = 1;
1713 case SSH_CMSG_REQUEST_PTY:
1715 debug("Allocating a pty not permitted for this authentication.");
1719 packet_disconnect("Protocol error: you already have a pty.");
1721 debug("Allocating pty.");
1723 /* Allocate a pty and open it. */
1724 if (!pty_allocate(&ptyfd, &ttyfd, ttyname,
1726 error("Failed to allocate pty.");
1729 fatal_add_cleanup(pty_release_proc, (void *)ttyname);
1730 pty_setowner(pw, ttyname);
1732 /* Get TERM from the packet. Note that the value may be of arbitrary length. */
1733 term = packet_get_string(&dlen);
1734 packet_integrity_check(dlen, strlen(term), type);
1736 /* Remaining bytes */
1737 n_bytes = plen - (4 + dlen + 4 * 4);
1739 if (strcmp(term, "") == 0) {
1744 /* Get window size from the packet. */
1745 row = packet_get_int();
1746 col = packet_get_int();
1747 xpixel = packet_get_int();
1748 ypixel = packet_get_int();
1749 pty_change_window_size(ptyfd, row, col, xpixel, ypixel);
1751 /* Get tty modes from the packet. */
1752 tty_parse_modes(ttyfd, &n_bytes);
1753 packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);
1755 /* Indicate that we now have a pty. */
1759 case SSH_CMSG_X11_REQUEST_FORWARDING:
1760 if (!options.x11_forwarding) {
1761 packet_send_debug("X11 forwarding disabled in server configuration file.");
1765 if (no_x11_forwarding_flag) {
1766 packet_send_debug("X11 forwarding not permitted for this authentication.");
1769 debug("Received request for X11 forwarding with auth spoofing.");
1771 packet_disconnect("Protocol error: X11 display already set.");
1773 int proto_len, data_len;
1774 proto = packet_get_string(&proto_len);
1775 data = packet_get_string(&data_len);
1776 packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type);
1778 if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER)
1779 screen = packet_get_int();
1782 display = x11_create_display_inet(screen, options.x11_display_offset);
1786 /* Setup to always have a local .Xauthority. */
1787 xauthfile = xmalloc(MAXPATHLEN);
1788 snprintf(xauthfile, MAXPATHLEN, "/tmp/XauthXXXXXX");
1790 if ((xauthfd = mkstemp(xauthfile)) != -1) {
1791 fchown(xauthfd, pw->pw_uid, pw->pw_gid);
1793 fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
1799 #else /* XAUTH_PATH */
1800 packet_send_debug("No xauth program; cannot forward with spoofing.");
1802 #endif /* XAUTH_PATH */
1804 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1805 if (no_agent_forwarding_flag || compat13) {
1806 debug("Authentication agent forwarding not permitted for this authentication.");
1809 debug("Received authentication agent forwarding request.");
1810 auth_input_request_forwarding(pw);
1813 case SSH_CMSG_PORT_FORWARD_REQUEST:
1814 if (no_port_forwarding_flag) {
1815 debug("Port forwarding not permitted for this authentication.");
1818 debug("Received TCP/IP port forwarding request.");
1819 channel_input_port_forward_request(pw->pw_uid == 0);
1822 case SSH_CMSG_MAX_PACKET_SIZE:
1823 if (packet_set_maxsize(packet_get_int()) < 0)
1827 case SSH_CMSG_EXEC_SHELL:
1828 /* Set interactive/non-interactive mode. */
1829 packet_set_interactive(have_pty || display != NULL,
1830 options.keepalives);
1832 if (forced_command != NULL)
1833 goto do_forced_command;
1834 debug("Forking shell.");
1835 packet_integrity_check(plen, 0, type);
1837 do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1839 do_exec_no_pty(NULL, pw, display, proto, data);
1842 case SSH_CMSG_EXEC_CMD:
1843 /* Set interactive/non-interactive mode. */
1844 packet_set_interactive(have_pty || display != NULL,
1845 options.keepalives);
1847 if (forced_command != NULL)
1848 goto do_forced_command;
1849 /* Get command from the packet. */
1852 command = packet_get_string(&dlen);
1853 debug("Executing command '%.500s'", command);
1854 packet_integrity_check(plen, 4 + dlen, type);
1857 do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1859 do_exec_no_pty(command, pw, display, proto, data);
1865 * Any unknown messages in this phase are ignored,
1866 * and a failure message is returned.
1868 log("Unknown packet type received after authentication: %d", type);
1872 /* The request was successfully processed. */
1873 packet_start(SSH_SMSG_SUCCESS);
1875 packet_write_wait();
1877 /* Enable compression now that we have replied if appropriate. */
1878 if (enable_compression_after_reply) {
1879 enable_compression_after_reply = 0;
1880 packet_start_compression(compression_level);
1885 /* The request failed. */
1886 packet_start(SSH_SMSG_FAILURE);
1888 packet_write_wait();
1893 * There is a forced command specified for this login.
1896 debug("Executing forced command: %.900s", forced_command);
1898 do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1900 do_exec_no_pty(forced_command, pw, display, proto, data);
1906 * This is called to fork and execute a command when we have no tty. This
1907 * will call do_child from the child, and server_loop from the parent after
1908 * setting up file descriptors and such.
1911 do_exec_no_pty(const char *command, struct passwd * pw,
1912 const char *display, const char *auth_proto,
1913 const char *auth_data)
1918 int pin[2], pout[2], perr[2];
1919 /* Allocate pipes for communicating with the program. */
1920 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
1921 packet_disconnect("Could not create pipes: %.100s",
1923 #else /* USE_PIPES */
1924 int inout[2], err[2];
1925 /* Uses socket pairs to communicate with the program. */
1926 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
1927 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
1928 packet_disconnect("Could not create socket pairs: %.100s",
1930 #endif /* USE_PIPES */
1932 setproctitle("%s@notty", pw->pw_name);
1936 #endif /* USE_PAM */
1938 /* Fork the child. */
1939 if ((pid = fork()) == 0) {
1940 /* Child. Reinitialize the log since the pid has changed. */
1941 log_init(av0, options.log_level, options.log_facility, log_stderr);
1944 * Create a new session and process group since the 4.4BSD
1945 * setlogin() affects the entire process group.
1948 error("setsid failed: %.100s", strerror(errno));
1952 * Redirect stdin. We close the parent side of the socket
1953 * pair, and make the child side the standard input.
1956 if (dup2(pin[0], 0) < 0)
1957 perror("dup2 stdin");
1960 /* Redirect stdout. */
1962 if (dup2(pout[1], 1) < 0)
1963 perror("dup2 stdout");
1966 /* Redirect stderr. */
1968 if (dup2(perr[1], 2) < 0)
1969 perror("dup2 stderr");
1971 #else /* USE_PIPES */
1973 * Redirect stdin, stdout, and stderr. Stdin and stdout will
1974 * use the same socket, as some programs (particularly rdist)
1975 * seem to depend on it.
1979 if (dup2(inout[0], 0) < 0) /* stdin */
1980 perror("dup2 stdin");
1981 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
1982 perror("dup2 stdout");
1983 if (dup2(err[0], 2) < 0) /* stderr */
1984 perror("dup2 stderr");
1985 #endif /* USE_PIPES */
1987 /* Do processing for the child (exec command etc). */
1988 do_child(command, pw, NULL, display, auth_proto, auth_data, NULL);
1992 packet_disconnect("fork failed: %.100s", strerror(errno));
1994 /* We are the parent. Close the child sides of the pipes. */
1999 /* Enter the interactive session. */
2000 server_loop(pid, pin[1], pout[0], perr[0]);
2001 /* server_loop has closed pin[1], pout[1], and perr[1]. */
2002 #else /* USE_PIPES */
2003 /* We are the parent. Close the child sides of the socket pairs. */
2008 * Enter the interactive session. Note: server_loop must be able to
2009 * handle the case that fdin and fdout are the same.
2011 server_loop(pid, inout[1], inout[1], err[1]);
2012 /* server_loop has closed inout[1] and err[1]. */
2013 #endif /* USE_PIPES */
2017 * This is called to fork and execute a command when we have a tty. This
2018 * will call do_child from the child, and server_loop from the parent after
2019 * setting up file descriptors, controlling tty, updating wtmp, utmp,
2020 * lastlog, and other such operations.
2023 do_exec_pty(const char *command, int ptyfd, int ttyfd,
2024 const char *ttyname, struct passwd * pw, const char *term,
2025 const char *display, const char *auth_proto,
2026 const char *auth_data)
2029 const char *hostname;
2030 time_t last_login_time;
2031 char buf[100], *time_string;
2036 struct sockaddr_storage from;
2038 struct pty_cleanup_context cleanup_context;
2040 /* Get remote host name. */
2041 hostname = get_canonical_hostname();
2044 * Get the time when the user last logged in. Buf will be set to
2045 * contain the hostname the last login was from.
2047 if (!options.use_login) {
2048 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
2051 setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1);
2054 do_pam_session(pw->pw_name, ttyname);
2056 #endif /* USE_PAM */
2058 /* Fork the child. */
2059 if ((pid = fork()) == 0) {
2062 /* Child. Reinitialize the log because the pid has
2064 log_init(av0, options.log_level, options.log_facility, log_stderr);
2066 /* Close the master side of the pseudo tty. */
2069 /* Make the pseudo tty our controlling tty. */
2070 pty_make_controlling_tty(&ttyfd, ttyname);
2072 /* Redirect stdin from the pseudo tty. */
2073 if (dup2(ttyfd, fileno(stdin)) < 0)
2074 error("dup2 stdin failed: %.100s", strerror(errno));
2076 /* Redirect stdout to the pseudo tty. */
2077 if (dup2(ttyfd, fileno(stdout)) < 0)
2078 error("dup2 stdin failed: %.100s", strerror(errno));
2080 /* Redirect stderr to the pseudo tty. */
2081 if (dup2(ttyfd, fileno(stderr)) < 0)
2082 error("dup2 stdin failed: %.100s", strerror(errno));
2084 /* Close the extra descriptor for the pseudo tty. */
2088 * Get IP address of client. This is needed because we want
2089 * to record where the user logged in from. If the
2090 * connection is not a socket, let the ip address be 0.0.0.0.
2092 memset(&from, 0, sizeof(from));
2093 if (packet_get_connection_in() == packet_get_connection_out()) {
2094 fromlen = sizeof(from);
2095 if (getpeername(packet_get_connection_in(),
2096 (struct sockaddr *) & from, &fromlen) < 0) {
2097 debug("getpeername: %.100s", strerror(errno));
2101 /* Record that there was a login on that terminal. */
2102 record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname,
2103 (struct sockaddr *)&from);
2105 /* Check if .hushlogin exists. */
2106 snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir);
2107 quiet_login = stat(line, &st) >= 0;
2111 print_pam_messages();
2112 #endif /* USE_PAM */
2115 * If the user has logged in before, display the time of last
2116 * login. However, don't display anything extra if a command
2117 * has been specified (so that ssh can be used to execute
2118 * commands on a remote machine without users knowing they
2119 * are going to another machine). Login(1) will do this for
2120 * us as well, so check if login(1) is used
2122 if (command == NULL && last_login_time != 0 && !quiet_login &&
2123 !options.use_login) {
2124 /* Convert the date to a string. */
2125 time_string = ctime(&last_login_time);
2126 /* Remove the trailing newline. */
2127 if (strchr(time_string, '\n'))
2128 *strchr(time_string, '\n') = 0;
2129 /* Display the last login time. Host if displayed
2131 if (strcmp(buf, "") == 0)
2132 printf("Last login: %s\r\n", time_string);
2134 printf("Last login: %s from %s\r\n", time_string, buf);
2137 * Print /etc/motd unless a command was specified or printing
2138 * it was disabled in server options or login(1) will be
2139 * used. Note that some machines appear to print it in
2140 * /etc/profile or similar.
2142 if (command == NULL && options.print_motd && !quiet_login &&
2143 !options.use_login) {
2144 /* Print /etc/motd if it exists. */
2145 f = fopen("/etc/motd", "r");
2147 while (fgets(line, sizeof(line), f))
2148 fputs(line, stdout);
2152 /* Do common processing for the child, such as execing the command. */
2153 do_child(command, pw, term, display, auth_proto, auth_data, ttyname);
2157 packet_disconnect("fork failed: %.100s", strerror(errno));
2158 /* Parent. Close the slave side of the pseudo tty. */
2162 * Add a cleanup function to clear the utmp entry and record logout
2163 * time in case we call fatal() (e.g., the connection gets closed).
2165 cleanup_context.pid = pid;
2166 cleanup_context.ttyname = ttyname;
2167 fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
2168 fatal_remove_cleanup(pty_release_proc, (void *) ttyname);
2171 * Create another descriptor of the pty master side for use as the
2172 * standard input. We could use the original descriptor, but this
2173 * simplifies code in server_loop. The descriptor is bidirectional.
2177 packet_disconnect("dup failed: %.100s", strerror(errno));
2179 /* Enter interactive session. */
2180 server_loop(pid, ptyfd, fdout, -1);
2181 /* server_loop has not closed ptyfd and fdout. */
2183 /* Cancel the cleanup function. */
2184 fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
2186 /* Record that the user has logged out. */
2187 record_logout(pid, ttyname);
2189 /* Release the pseudo-tty. */
2190 pty_release(ttyname);
2193 * Close the server side of the socket pairs. We must do this after
2194 * the pty cleanup, so that another process doesn't get this pty
2195 * while we're still cleaning up.
2202 * Sets the value of the given variable in the environment. If the variable
2203 * already exists, its value is overriden.
2206 child_set_env(char ***envp, unsigned int *envsizep, const char *name,
2209 unsigned int i, namelen;
2213 * Find the slot where the value should be stored. If the variable
2214 * already exists, we reuse the slot; otherwise we append a new slot
2215 * at the end of the array, expanding if necessary.
2218 namelen = strlen(name);
2219 for (i = 0; env[i]; i++)
2220 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
2223 /* Reuse the slot. */
2226 /* New variable. Expand if necessary. */
2227 if (i >= (*envsizep) - 1) {
2229 env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
2231 /* Need to set the NULL pointer at end of array beyond the new slot. */
2235 /* Allocate space and format the variable in the appropriate slot. */
2236 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
2237 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
2241 * Reads environment variables from the given file and adds/overrides them
2242 * into the environment. If the file does not exist, this does nothing.
2243 * Otherwise, it must consist of empty lines, comments (line starts with '#')
2244 * and assignments of the form name=value. No other forms are allowed.
2247 read_environment_file(char ***env, unsigned int *envsize,
2248 const char *filename)
2254 f = fopen(filename, "r");
2258 while (fgets(buf, sizeof(buf), f)) {
2259 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
2261 if (!*cp || *cp == '#' || *cp == '\n')
2263 if (strchr(cp, '\n'))
2264 *strchr(cp, '\n') = '\0';
2265 value = strchr(cp, '=');
2266 if (value == NULL) {
2267 fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
2270 /* Replace the equals sign by nul, and advance value to the value string. */
2273 child_set_env(env, envsize, cp, value);
2280 * Sets any environment variables which have been specified by PAM
2282 void do_pam_environment(char ***env, int *envsize)
2284 char *equals, var_name[512], var_val[512];
2288 if ((pam_env = fetch_pam_environment()) == NULL)
2291 for(i = 0; pam_env[i] != NULL; i++) {
2292 if ((equals = strstr(pam_env[i], "=")) == NULL)
2295 if (strlen(pam_env[i]) < (sizeof(var_name) - 1))
2297 memset(var_name, '\0', sizeof(var_name));
2298 memset(var_val, '\0', sizeof(var_val));
2300 strncpy(var_name, pam_env[i], equals - pam_env[i]);
2301 strcpy(var_val, equals + 1);
2303 debug("PAM environment: %s=%s", var_name, var_val);
2305 child_set_env(env, envsize, var_name, var_val);
2309 #endif /* USE_PAM */
2312 * Performs common processing for the child, such as setting up the
2313 * environment, closing extra file descriptors, setting the user and group
2314 * ids, and executing the command or shell.
2317 do_child(const char *command, struct passwd * pw, const char *term,
2318 const char *display, const char *auth_proto,
2319 const char *auth_data, const char *ttyname)
2321 const char *shell, *cp = NULL;
2324 unsigned int envsize, i;
2326 extern char **environ;
2330 #ifndef USE_PAM /* pam_nologin handles this */
2331 /* Check /etc/nologin. */
2332 f = fopen("/etc/nologin", "r");
2334 /* /etc/nologin exists. Print its contents and exit. */
2335 while (fgets(buf, sizeof(buf), f))
2338 if (pw->pw_uid != 0)
2341 #endif /* USE_PAM */
2343 /* Set login name in the kernel. */
2344 if (setlogin(pw->pw_name) < 0)
2345 error("setlogin failed: %s", strerror(errno));
2347 /* Set uid, gid, and groups. */
2348 /* Login(1) does this as well, and it needs uid 0 for the "-h"
2349 switch, so we let login(1) to this for us. */
2350 if (!options.use_login) {
2351 if (getuid() == 0 || geteuid() == 0) {
2352 if (setgid(pw->pw_gid) < 0) {
2356 /* Initialize the group list. */
2357 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
2358 perror("initgroups");
2363 /* Permanently switch to the desired uid. */
2364 permanently_set_uid(pw->pw_uid);
2366 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
2367 fatal("Failed to set uids to %d.", (int) pw->pw_uid);
2370 * Get the shell from the password data. An empty shell field is
2371 * legal, and means /bin/sh.
2373 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
2376 /* Try to get AFS tokens for the local cell. */
2380 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
2381 krb_afslog(cell, 0);
2387 /* Initialize the environment. */
2389 env = xmalloc(envsize * sizeof(char *));
2392 if (!options.use_login) {
2393 /* Set basic environment. */
2394 child_set_env(&env, &envsize, "USER", pw->pw_name);
2395 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
2396 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
2397 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
2399 snprintf(buf, sizeof buf, "%.200s/%.50s",
2400 _PATH_MAILDIR, pw->pw_name);
2401 child_set_env(&env, &envsize, "MAIL", buf);
2403 /* Normal systems set SHELL by default. */
2404 child_set_env(&env, &envsize, "SHELL", shell);
2407 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
2409 /* Set custom environment options from RSA authentication. */
2410 while (custom_environment) {
2411 struct envstring *ce = custom_environment;
2414 for (i = 0; s[i] != '=' && s[i]; i++);
2417 child_set_env(&env, &envsize, s, s + i + 1);
2419 custom_environment = ce->next;
2424 snprintf(buf, sizeof buf, "%.50s %d %d",
2425 get_remote_ipaddr(), get_remote_port(), get_local_port());
2426 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
2429 child_set_env(&env, &envsize, "SSH_TTY", ttyname);
2431 child_set_env(&env, &envsize, "TERM", term);
2433 child_set_env(&env, &envsize, "DISPLAY", display);
2437 char *authstate,*krb5cc;
2439 if ((authstate = getenv("AUTHSTATE")) != NULL)
2440 child_set_env(&env,&envsize,"AUTHSTATE",authstate);
2442 if ((krb5cc = getenv("KRB5CCNAME")) != NULL)
2443 child_set_env(&env,&envsize,"KRB5CCNAME",krb5cc);
2449 extern char *ticket;
2452 child_set_env(&env, &envsize, "KRBTKFILE", ticket);
2457 /* Pull in any environment variables that may have been set by PAM. */
2458 do_pam_environment(&env, &envsize);
2459 #endif /* USE_PAM */
2462 child_set_env(&env, &envsize, "XAUTHORITY", xauthfile);
2464 if (auth_get_socket_name() != NULL)
2465 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
2466 auth_get_socket_name());
2468 read_environment_file(&env,&envsize,"/etc/environment");
2470 /* read $HOME/.ssh/environment. */
2471 if (!options.use_login) {
2472 snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir);
2473 read_environment_file(&env, &envsize, buf);
2476 /* dump the environment */
2477 fprintf(stderr, "Environment:\n");
2478 for (i = 0; env[i]; i++)
2479 fprintf(stderr, " %.200s\n", env[i]);
2482 * Close the connection descriptors; note that this is the child, and
2483 * the server will still have the socket open, and it is important
2484 * that we do not shutdown it. Note that the descriptors cannot be
2485 * closed before building the environment, as we call
2486 * get_remote_ipaddr there.
2488 if (packet_get_connection_in() == packet_get_connection_out())
2489 close(packet_get_connection_in());
2491 close(packet_get_connection_in());
2492 close(packet_get_connection_out());
2495 * Close all descriptors related to channels. They will still remain
2496 * open in the parent.
2498 /* XXX better use close-on-exec? -markus */
2499 channel_close_all();
2502 * Close any extra file descriptors. Note that there may still be
2503 * descriptors left by system functions. They will be closed later.
2508 * Close any extra open file descriptors so that we don\'t have them
2509 * hanging around in clients. Note that we want to do this after
2510 * initgroups, because at least on Solaris 2.3 it leaves file
2513 for (i = 3; i < 64; i++)
2516 /* Change current directory to the user\'s home directory. */
2517 if (chdir(pw->pw_dir) < 0)
2518 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
2519 pw->pw_dir, strerror(errno));
2522 * Must take new environment into use so that .ssh/rc, /etc/sshrc and
2523 * xauth are run in the proper environment.
2528 * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
2531 if (!options.use_login) {
2532 if (stat(SSH_USER_RC, &st) >= 0) {
2534 fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC);
2536 f = popen("/bin/sh " SSH_USER_RC, "w");
2538 if (auth_proto != NULL && auth_data != NULL)
2539 fprintf(f, "%s %s\n", auth_proto, auth_data);
2542 fprintf(stderr, "Could not run %s\n", SSH_USER_RC);
2543 } else if (stat(SSH_SYSTEM_RC, &st) >= 0) {
2545 fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC);
2547 f = popen("/bin/sh " SSH_SYSTEM_RC, "w");
2549 if (auth_proto != NULL && auth_data != NULL)
2550 fprintf(f, "%s %s\n", auth_proto, auth_data);
2553 fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC);
2557 /* Add authority data to .Xauthority if appropriate. */
2558 if (auth_proto != NULL && auth_data != NULL) {
2560 fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n",
2561 XAUTH_PATH, display, auth_proto, auth_data);
2563 f = popen(XAUTH_PATH " -q -", "w");
2565 fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data);
2568 fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH);
2571 #endif /* XAUTH_PATH */
2573 /* Get the last component of the shell name. */
2574 cp = strrchr(shell, '/');
2581 * If we have no command, execute the shell. In this case, the shell
2582 * name to be passed in argv[0] is preceded by '-' to indicate that
2583 * this is a login shell.
2586 if (!options.use_login) {
2590 * Check for mail if we have a tty and it was enabled
2591 * in server options.
2593 if (ttyname && options.check_mail) {
2595 struct stat mailstat;
2596 mailbox = getenv("MAIL");
2597 if (mailbox != NULL) {
2598 if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0)
2599 printf("No mail.\n");
2600 else if (mailstat.st_mtime < mailstat.st_atime)
2601 printf("You have mail.\n");
2603 printf("You have new mail.\n");
2606 /* Start the shell. Set initial character to '-'. */
2608 strncpy(buf + 1, cp, sizeof(buf) - 1);
2609 buf[sizeof(buf) - 1] = 0;
2611 /* Execute the shell. */
2614 execve(shell, argv, env);
2616 /* Executing the shell failed. */
2621 /* Launch login(1). */
2623 execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(),
2624 "-p", "-f", "--", pw->pw_name, NULL);
2626 /* Login couldn't be executed, die. */
2633 * Execute the command using the user's shell. This uses the -c
2634 * option to execute the command.
2636 argv[0] = (char *) cp;
2638 argv[2] = (char *) command;
2640 execve(shell, argv, env);