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
18 #else /* HAVE_POLL_H */
19 # ifdef HAVE_SYS_POLL_H
20 # include <sys/poll.h>
21 # endif /* HAVE_SYS_POLL_H */
22 #endif /* HAVE_POLL_H */
39 int allow_severity = LOG_INFO;
40 int deny_severity = LOG_WARNING;
47 /* Local Xauthority file. */
48 static char *xauthfile = NULL;
50 /* Server configuration options. */
51 ServerOptions options;
53 /* Name of the server configuration file. */
54 char *config_file_name = SERVER_CONFIG_FILE;
57 * Debug mode flag. This can be set on the command line. If debug
58 * mode is enabled, extra debugging output will be sent to the system
59 * log, the daemon will not go to background, and will exit after processing
60 * the first connection.
64 /* Flag indicating that the daemon is being started from inetd. */
67 /* debug goes to stderr unless inetd_flag is set */
70 /* argv[0] without path. */
73 /* Saved arguments to main(). */
77 * This is set to the socket that the server is listening; this is used in
78 * the SIGHUP signal handler.
83 * the client's version string, passed by sshd2 in compat mode. if != NULL,
84 * sshd will skip the version-number exchange
86 char *client_version_string = NULL;
88 /* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */
89 int no_port_forwarding_flag = 0;
90 int no_agent_forwarding_flag = 0;
91 int no_x11_forwarding_flag = 0;
94 /* RSA authentication "command=" option. */
95 char *forced_command = NULL;
97 /* RSA authentication "environment=" options. */
98 struct envstring *custom_environment = NULL;
100 /* Session id for the current session. */
101 unsigned char session_id[16];
104 * Any really sensitive data in the application is contained in this
105 * structure. The idea is that this structure could be locked into memory so
106 * that the pages do not get written into swap. However, there are some
107 * problems. The private key contains BIGNUMs, and we do not (in principle)
108 * have access to the internals of them, and locking just the structure is
109 * not very useful. Currently, memory locking is not implemented.
112 RSA *private_key; /* Private part of server key. */
113 RSA *host_key; /* Private part of host key. */
117 * Flag indicating whether the current session key has been used. This flag
118 * is set whenever the key is used, and cleared when the key is regenerated.
122 /* This is set to true when SIGHUP is received. */
123 int received_sighup = 0;
125 /* Public side of the server key. This value is regenerated regularly with
129 /* Prototypes for various functions defined later in this file. */
130 void do_connection();
131 void do_authentication(char *user);
132 void do_authloop(struct passwd * pw);
133 void do_fake_authloop(char *user);
134 void do_authenticated(struct passwd * pw);
135 void do_exec_pty(const char *command, int ptyfd, int ttyfd,
136 const char *ttyname, struct passwd * pw, const char *term,
137 const char *display, const char *auth_proto,
138 const char *auth_data);
139 void do_exec_no_pty(const char *command, struct passwd * pw,
140 const char *display, const char *auth_proto,
141 const char *auth_data);
142 void do_child(const char *command, struct passwd * pw, const char *term,
143 const char *display, const char *auth_proto,
144 const char *auth_data, const char *ttyname);
147 static int pamconv(int num_msg, const struct pam_message **msg,
148 struct pam_response **resp, void *appdata_ptr);
149 int do_pam_auth(const char *user, const char *password);
150 void do_pam_account(char *username, char *remote_user);
151 void do_pam_session(char *username, char *ttyname);
152 void pam_cleanup_proc(void *context);
154 static struct pam_conv conv = {
158 struct pam_handle_t *pamh = NULL;
159 const char *pampasswd = NULL;
160 char *pamconv_msg = NULL;
162 static int pamconv(int num_msg, const struct pam_message **msg,
163 struct pam_response **resp, void *appdata_ptr)
165 struct pam_response *reply;
170 /* PAM will free this later */
171 reply = malloc(num_msg * sizeof(*reply));
175 for(count = 0; count < num_msg; count++) {
176 switch (msg[count]->msg_style) {
177 case PAM_PROMPT_ECHO_OFF:
178 if (pampasswd == NULL) {
182 reply[count].resp_retcode = PAM_SUCCESS;
183 reply[count].resp = xstrdup(pampasswd);
187 reply[count].resp_retcode = PAM_SUCCESS;
188 reply[count].resp = xstrdup("");
190 if (msg[count]->msg == NULL)
193 debug("Adding PAM message: %s", msg[count]->msg);
195 msg_len = strlen(msg[count]->msg);
197 size_t n = strlen(pamconv_msg);
198 pamconv_msg = xrealloc(pamconv_msg, n + msg_len + 2);
201 pamconv_msg = p = xmalloc(msg_len + 2);
203 memcpy(p, msg[count]->msg, msg_len);
205 p[msg_len + 1] = '\0';
208 case PAM_PROMPT_ECHO_ON:
221 void pam_cleanup_proc(void *context)
227 pam_retval = pam_close_session((pam_handle_t *)pamh, 0);
228 if (pam_retval != PAM_SUCCESS) {
229 log("Cannot close PAM session: %.200s",
230 PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
233 pam_retval = pam_end((pam_handle_t *)pamh, pam_retval);
234 if (pam_retval != PAM_SUCCESS) {
235 log("Cannot release PAM authentication: %.200s",
236 PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
241 int do_pam_auth(const char *user, const char *password)
245 if ((options.permit_empty_passwd == 0) && (password[0] == '\0'))
248 pampasswd = password;
250 pam_retval = pam_authenticate((pam_handle_t *)pamh, 0);
251 if (pam_retval == PAM_SUCCESS) {
252 debug("PAM Password authentication accepted for user \"%.100s\"", user);
255 debug("PAM Password authentication for \"%.100s\" failed: %s",
256 user, PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
261 void do_pam_account(char *username, char *remote_user)
265 debug("PAM setting rhost to \"%.200s\"", get_canonical_hostname());
266 pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RHOST,
267 get_canonical_hostname());
268 if (pam_retval != PAM_SUCCESS) {
269 log("PAM set rhost failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
270 do_fake_authloop(username);
273 if (remote_user != NULL) {
274 debug("PAM setting ruser to \"%.200s\"", remote_user);
275 pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RUSER, remote_user);
276 if (pam_retval != PAM_SUCCESS) {
277 log("PAM set ruser failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
278 do_fake_authloop(username);
282 pam_retval = pam_acct_mgmt((pam_handle_t *)pamh, 0);
283 if (pam_retval != PAM_SUCCESS) {
284 log("PAM rejected by account configuration: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
285 do_fake_authloop(username);
289 void do_pam_session(char *username, char *ttyname)
293 if (ttyname != NULL) {
294 debug("PAM setting tty to \"%.200s\"", ttyname);
295 pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_TTY, ttyname);
296 if (pam_retval != PAM_SUCCESS)
297 fatal("PAM set tty failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
300 pam_retval = pam_open_session((pam_handle_t *)pamh, 0);
301 if (pam_retval != PAM_SUCCESS)
302 fatal("PAM session setup failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
307 * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
308 * the effect is to reread the configuration file (and to regenerate
312 sighup_handler(int sig)
315 signal(SIGHUP, sighup_handler);
319 * Called from the main program after receiving SIGHUP.
320 * Restarts the server.
325 log("Received SIGHUP; restarting.");
327 execv(saved_argv[0], saved_argv);
328 log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno));
333 * Generic signal handler for terminating signals in the master daemon.
334 * These close the listen socket; not closing it seems to cause "Address
335 * already in use" problems on some machines, which is inconvenient.
338 sigterm_handler(int sig)
340 log("Received signal %d; terminating.", sig);
346 * SIGCHLD handler. This is called whenever a child dies. This will then
347 * reap any zombies left by exited c.
350 main_sigchld_handler(int sig)
352 int save_errno = errno;
355 while (waitpid(-1, &status, WNOHANG) > 0)
358 signal(SIGCHLD, main_sigchld_handler);
363 * Signal handler for the alarm after the login grace period has expired.
366 grace_alarm_handler(int sig)
368 /* Close the connection. */
371 /* Log error and exit. */
372 fatal("Timeout before authentication for %s.", get_remote_ipaddr());
376 * convert ssh auth msg type into description
379 get_authname(int type)
382 case SSH_CMSG_AUTH_PASSWORD:
384 case SSH_CMSG_AUTH_RSA:
386 case SSH_CMSG_AUTH_RHOSTS_RSA:
388 case SSH_CMSG_AUTH_RHOSTS:
391 case SSH_CMSG_AUTH_KERBEROS:
395 case SSH_CMSG_AUTH_TIS_RESPONSE:
399 fatal("get_authname: unknown auth %d: internal error", type);
404 * Signal handler for the key regeneration alarm. Note that this
405 * alarm only occurs in the daemon waiting for connections, and it does not
406 * do anything with the private key or random state before forking.
407 * Thus there should be no concurrency control/asynchronous execution
411 key_regeneration_alarm(int sig)
413 int save_errno = errno;
415 /* Check if we should generate a new key. */
417 /* This should really be done in the background. */
418 log("Generating new %d bit RSA key.", options.server_key_bits);
420 if (sensitive_data.private_key != NULL)
421 RSA_free(sensitive_data.private_key);
422 sensitive_data.private_key = RSA_new();
424 if (public_key != NULL)
425 RSA_free(public_key);
426 public_key = RSA_new();
428 rsa_generate_key(sensitive_data.private_key, public_key,
429 options.server_key_bits);
432 log("RSA key generation complete.");
434 /* Reschedule the alarm. */
435 signal(SIGALRM, key_regeneration_alarm);
436 alarm(options.key_regeneration_time);
441 * Main program for the daemon.
444 main(int ac, char **av)
448 int opt, aux, sock_in, sock_out, newsock, i, pid, on = 1;
449 int remote_major, remote_minor;
452 struct sockaddr_in sin;
453 char buf[100]; /* Must not be larger than remote_version. */
454 char remote_version[100]; /* Must be at least as big as buf. */
455 const char *remote_ip;
459 struct linger linger;
463 if (strchr(av[0], '/'))
464 av0 = strrchr(av[0], '/') + 1;
468 /* Initialize configuration options to their default values. */
469 initialize_server_options(&options);
471 /* Parse command-line arguments. */
472 while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ")) != EOF) {
475 config_file_name = optarg;
479 options.log_level = SYSLOG_LEVEL_DEBUG;
488 options.log_level = SYSLOG_LEVEL_QUIET;
491 options.server_key_bits = atoi(optarg);
494 options.port = atoi(optarg);
497 options.login_grace_time = atoi(optarg);
500 options.key_regeneration_time = atoi(optarg);
503 options.host_key_file = optarg;
506 client_version_string = optarg;
507 /* only makes sense with inetd_flag, i.e. no listen() */
512 fprintf(stderr, "sshd version %s\n", SSH_VERSION);
513 fprintf(stderr, "Usage: %s [options]\n", av0);
514 fprintf(stderr, "Options:\n");
515 fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE);
516 fprintf(stderr, " -d Debugging mode\n");
517 fprintf(stderr, " -i Started from inetd\n");
518 fprintf(stderr, " -q Quiet (no logging)\n");
519 fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
520 fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
521 fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n");
522 fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
523 fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
529 /* check if RSA support exists */
530 if (rsa_alive() == 0) {
532 printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n");
533 log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)");
536 /* Read server configuration options from the configuration file. */
537 read_server_config(&options, config_file_name);
539 /* Fill in default values for those options not explicitly set. */
540 fill_default_server_options(&options);
542 /* Check certain values for sanity. */
543 if (options.server_key_bits < 512 ||
544 options.server_key_bits > 32768) {
545 fprintf(stderr, "Bad server key size.\n");
548 if (options.port < 1 || options.port > 65535) {
549 fprintf(stderr, "Bad port number.\n");
552 /* Check that there are no remaining arguments. */
554 fprintf(stderr, "Extra argument %s.\n", av[optind]);
557 /* Force logging to stderr while loading the private host key
558 unless started from inetd */
559 log_init(av0, options.log_level, options.log_facility, !inetd_flag);
561 debug("sshd version %.100s", SSH_VERSION);
563 sensitive_data.host_key = RSA_new();
565 /* Load the host key. It must have empty passphrase. */
566 if (!load_private_key(options.host_key_file, "",
567 sensitive_data.host_key, &comment)) {
568 error("Could not load host key: %.200s: %.100s",
569 options.host_key_file, strerror(errno));
574 /* Initialize the log (it is reinitialized below in case we
576 if (debug_flag && !inetd_flag)
578 log_init(av0, options.log_level, options.log_facility, log_stderr);
580 /* If not in debugging mode, and not started from inetd,
581 disconnect from the controlling terminal, and fork. The
582 original process exits. */
583 if (!debug_flag && !inetd_flag) {
586 #endif /* TIOCNOTTY */
587 if (daemon(0, 0) < 0)
588 fatal("daemon() failed: %.200s", strerror(errno));
590 /* Disconnect from the controlling tty. */
592 fd = open("/dev/tty", O_RDWR | O_NOCTTY);
594 (void) ioctl(fd, TIOCNOTTY, NULL);
597 #endif /* TIOCNOTTY */
599 /* Reinitialize the log (because of the fork above). */
600 log_init(av0, options.log_level, options.log_facility, log_stderr);
602 /* Check that server and host key lengths differ sufficiently.
603 This is necessary to make double encryption work with rsaref.
604 Oh, I hate software patents. I dont know if this can go? Niels */
605 if (options.server_key_bits >
606 BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
607 options.server_key_bits <
608 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
609 options.server_key_bits =
610 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
611 debug("Forcing server key to %d bits to make it differ from host key.",
612 options.server_key_bits);
614 /* Do not display messages to stdout in RSA code. */
617 /* Initialize the random number generator. */
620 /* Chdir to the root directory so that the current disk can be
621 unmounted if desired. */
624 /* Close connection cleanly after attack. */
625 cipher_attack_detected = packet_disconnect;
627 /* Start listening for a socket, unless started from inetd. */
630 s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
634 /* We intentionally do not close the descriptors 0, 1, and 2
635 as our code for setting the descriptors won\'t work
636 if ttyfd happens to be one of those. */
637 debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
639 public_key = RSA_new();
640 sensitive_data.private_key = RSA_new();
642 log("Generating %d bit RSA key.", options.server_key_bits);
643 rsa_generate_key(sensitive_data.private_key, public_key,
644 options.server_key_bits);
646 log("RSA key generation complete.");
648 /* Create socket for listening. */
649 listen_sock = socket(AF_INET, SOCK_STREAM, 0);
651 fatal("socket: %.100s", strerror(errno));
653 /* Set socket options. We try to make the port reusable
654 and have it close as fast as possible without waiting
655 in unnecessary wait states on close. */
656 setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, (void *) &on,
660 setsockopt(listen_sock, SOL_SOCKET, SO_LINGER, (void *) &linger,
663 memset(&sin, 0, sizeof(sin));
664 sin.sin_family = AF_INET;
665 sin.sin_addr = options.listen_addr;
666 sin.sin_port = htons(options.port);
668 if (bind(listen_sock, (struct sockaddr *) & sin, sizeof(sin)) < 0) {
669 error("bind: %.100s", strerror(errno));
670 shutdown(listen_sock, SHUT_RDWR);
672 fatal("Bind to port %d failed.", options.port);
676 * Record our pid in /etc/sshd_pid to make it easier
677 * to kill the correct sshd. We don\'t want to do
678 * this before the bind above because the bind will
679 * fail if there already is a daemon, and this will
680 * overwrite any old pid in the file.
682 f = fopen(SSH_DAEMON_PID_FILE, "w");
684 fprintf(f, "%u\n", (unsigned int) getpid());
689 log("Server listening on port %d.", options.port);
690 if (listen(listen_sock, 5) < 0)
691 fatal("listen: %.100s", strerror(errno));
693 public_key = RSA_new();
694 sensitive_data.private_key = RSA_new();
696 log("Generating %d bit RSA key.", options.server_key_bits);
697 rsa_generate_key(sensitive_data.private_key, public_key,
698 options.server_key_bits);
700 log("RSA key generation complete.");
702 /* Schedule server key regeneration alarm. */
703 signal(SIGALRM, key_regeneration_alarm);
704 alarm(options.key_regeneration_time);
706 /* Arrange to restart on SIGHUP. The handler needs listen_sock. */
707 signal(SIGHUP, sighup_handler);
708 signal(SIGTERM, sigterm_handler);
709 signal(SIGQUIT, sigterm_handler);
711 /* Arrange SIGCHLD to be caught. */
712 signal(SIGCHLD, main_sigchld_handler);
715 * Stay listening for connections until the system crashes or
716 * the daemon is killed with a signal.
721 /* Wait in poll until there is a connection. */
722 memset(&fds, 0, sizeof(fds));
723 fds.fd = listen_sock;
725 if (poll(&fds, 1, -1) == -1) {
728 fatal("poll: %.100s", strerror(errno));
731 if (fds.revents == 0)
734 newsock = accept(listen_sock, (struct sockaddr *) & sin, &aux);
740 error("accept: %.100s", strerror(errno));
744 * Got connection. Fork a child to handle it, unless
745 * we are in debugging mode.
749 * In debugging mode. Close the listening
750 * socket, and start processing the
751 * connection without forking.
753 debug("Server will not fork when running in debugging mode.");
761 * Normal production daemon. Fork, and have
762 * the child process the connection. The
763 * parent continues listening.
765 if ((pid = fork()) == 0) {
767 * Child. Close the listening socket, and start using the
768 * accepted socket. Reinitialize logging (since our pid has
769 * changed). We break out of the loop to handle the connection.
774 log_init(av0, options.log_level, options.log_facility, log_stderr);
779 /* Parent. Stay in the loop. */
781 error("fork: %.100s", strerror(errno));
783 debug("Forked child %d.", pid);
785 /* Mark that the key has been used (it was "given" to the child). */
790 /* Close the new socket (the child is now taking care of it). */
795 /* This is the child processing a new connection. */
798 * Disable the key regeneration alarm. We will not regenerate the
799 * key since we are no longer in a position to give it to anyone. We
800 * will not restart on SIGHUP since it no longer makes sense.
803 signal(SIGALRM, SIG_DFL);
804 signal(SIGHUP, SIG_DFL);
805 signal(SIGTERM, SIG_DFL);
806 signal(SIGQUIT, SIG_DFL);
807 signal(SIGCHLD, SIG_DFL);
810 * Set socket options for the connection. We want the socket to
811 * close as fast as possible without waiting for anything. If the
812 * connection is not a socket, these will do nothing.
814 /* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
817 setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
820 * Register our connection. This turns encryption off because we do
823 packet_set_connection(sock_in, sock_out);
825 remote_port = get_remote_port();
826 remote_ip = get_remote_ipaddr();
828 /* Check whether logins are denied from this host. */
831 struct request_info req;
833 request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL);
836 if (!hosts_access(&req)) {
841 verbose("Connection from %.500s port %d", eval_client(&req), remote_port);
844 /* Log the connection. */
845 verbose("Connection from %.500s port %d", remote_ip, remote_port);
849 * We don\'t want to listen forever unless the other side
850 * successfully authenticates itself. So we set up an alarm which is
851 * cleared after successful authentication. A limit of zero
852 * indicates no limit. Note that we don\'t set the alarm in debugging
853 * mode; it is just annoying to have the server exit just when you
854 * are about to discover the bug.
856 signal(SIGALRM, grace_alarm_handler);
858 alarm(options.login_grace_time);
860 if (client_version_string != NULL) {
861 /* we are exec'ed by sshd2, so skip exchange of protocol version */
862 strlcpy(buf, client_version_string, sizeof(buf));
864 /* Send our protocol version identification. */
865 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
866 PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
867 if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf))
868 fatal("Could not write ident string to %s.", get_remote_ipaddr());
870 /* Read other side\'s version identification. */
871 for (i = 0; i < sizeof(buf) - 1; i++) {
872 if (read(sock_in, &buf[i], 1) != 1)
873 fatal("Did not receive ident string from %s.", get_remote_ipaddr());
874 if (buf[i] == '\r') {
879 if (buf[i] == '\n') {
885 buf[sizeof(buf) - 1] = 0;
889 * Check that the versions match. In future this might accept
890 * several versions and set appropriate flags to handle them.
892 if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor,
893 remote_version) != 3) {
894 char *s = "Protocol mismatch.\n";
896 (void) atomicio(write, sock_out, s, strlen(s));
899 fatal("Bad protocol version identification '%.100s' from %s",
900 buf, get_remote_ipaddr());
902 debug("Client protocol version %d.%d; client software version %.100s",
903 remote_major, remote_minor, remote_version);
904 if (remote_major != PROTOCOL_MAJOR) {
905 char *s = "Protocol major versions differ.\n";
907 (void) atomicio(write, sock_out, s, strlen(s));
910 fatal("Protocol major versions differ for %s: %d vs. %d",
912 PROTOCOL_MAJOR, remote_major);
914 /* Check that the client has sufficiently high software version. */
915 if (remote_major == 1 && remote_minor < 3)
916 packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version.");
918 if (remote_major == 1 && remote_minor == 3) {
920 if (strcmp(remote_version, "OpenSSH-1.1") != 0) {
921 debug("Agent forwarding disabled, remote version is not compatible.");
922 no_agent_forwarding_flag = 1;
926 * Check that the connection comes from a privileged port. Rhosts-
927 * and Rhosts-RSA-Authentication only make sense from priviledged
928 * programs. Of course, if the intruder has root access on his local
929 * machine, he can connect from any port. So do not use these
930 * authentication methods from machines that you do not trust.
932 if (remote_port >= IPPORT_RESERVED ||
933 remote_port < IPPORT_RESERVED / 2) {
934 options.rhosts_authentication = 0;
935 options.rhosts_rsa_authentication = 0;
937 packet_set_nonblocking();
939 /* Handle the connection. */
943 /* Cleanup user's ticket cache file. */
944 if (options.kerberos_ticket_cleanup)
948 /* Cleanup user's local Xauthority file. */
952 /* The connection has been terminated. */
953 verbose("Closing connection to %.100s", remote_ip);
960 debug("Closing PAM session.");
961 retval = pam_close_session((pam_handle_t *)pamh, 0);
963 debug("Terminating PAM library.");
964 if (pam_end((pam_handle_t *)pamh, retval) != PAM_SUCCESS)
965 log("Cannot release PAM authentication.");
967 fatal_remove_cleanup(&pam_cleanup_proc, NULL);
977 * Process an incoming connection. Protocol version identifiers have already
978 * been exchanged. This sends server key and performs the key exchange.
979 * Server and host keys will no longer be needed after this functions.
985 BIGNUM *session_key_int;
986 unsigned char session_key[SSH_SESSION_KEY_LENGTH];
987 unsigned char check_bytes[8];
989 unsigned int cipher_type, auth_mask, protocol_flags;
990 int plen, slen, ulen;
994 * Generate check bytes that the client must send back in the user
995 * packet in order for it to be accepted; this is used to defy ip
996 * spoofing attacks. Note that this only works against somebody
997 * doing IP spoofing from a remote machine; any machine on the local
998 * network can still see outgoing packets and catch the random
999 * cookie. This only affects rhosts authentication, and this is one
1000 * of the reasons why it is inherently insecure.
1002 for (i = 0; i < 8; i++) {
1004 rand = arc4random();
1005 check_bytes[i] = rand & 0xff;
1010 * Send our public key. We include in the packet 64 bits of random
1011 * data that must be matched in the reply in order to prevent IP
1014 packet_start(SSH_SMSG_PUBLIC_KEY);
1015 for (i = 0; i < 8; i++)
1016 packet_put_char(check_bytes[i]);
1018 /* Store our public server RSA key. */
1019 packet_put_int(BN_num_bits(public_key->n));
1020 packet_put_bignum(public_key->e);
1021 packet_put_bignum(public_key->n);
1023 /* Store our public host RSA key. */
1024 packet_put_int(BN_num_bits(sensitive_data.host_key->n));
1025 packet_put_bignum(sensitive_data.host_key->e);
1026 packet_put_bignum(sensitive_data.host_key->n);
1028 /* Put protocol flags. */
1029 packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
1031 /* Declare which ciphers we support. */
1032 packet_put_int(cipher_mask());
1034 /* Declare supported authentication types. */
1036 if (options.rhosts_authentication)
1037 auth_mask |= 1 << SSH_AUTH_RHOSTS;
1038 if (options.rhosts_rsa_authentication)
1039 auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
1040 if (options.rsa_authentication)
1041 auth_mask |= 1 << SSH_AUTH_RSA;
1043 if (options.kerberos_authentication)
1044 auth_mask |= 1 << SSH_AUTH_KERBEROS;
1047 if (options.kerberos_tgt_passing)
1048 auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
1049 if (options.afs_token_passing)
1050 auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
1053 if (options.skey_authentication == 1)
1054 auth_mask |= 1 << SSH_AUTH_TIS;
1056 if (options.password_authentication)
1057 auth_mask |= 1 << SSH_AUTH_PASSWORD;
1058 packet_put_int(auth_mask);
1060 /* Send the packet and wait for it to be sent. */
1062 packet_write_wait();
1064 debug("Sent %d bit public key and %d bit host key.",
1065 BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n));
1067 /* Read clients reply (cipher type and session key). */
1068 packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
1070 /* Get cipher type and check whether we accept this. */
1071 cipher_type = packet_get_char();
1073 if (!(cipher_mask() & (1 << cipher_type)))
1074 packet_disconnect("Warning: client selects unsupported cipher.");
1076 /* Get check bytes from the packet. These must match those we
1077 sent earlier with the public key packet. */
1078 for (i = 0; i < 8; i++)
1079 if (check_bytes[i] != packet_get_char())
1080 packet_disconnect("IP Spoofing check bytes do not match.");
1082 debug("Encryption type: %.200s", cipher_name(cipher_type));
1084 /* Get the encrypted integer. */
1085 session_key_int = BN_new();
1086 packet_get_bignum(session_key_int, &slen);
1088 protocol_flags = packet_get_int();
1089 packet_set_protocol_flags(protocol_flags);
1091 packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
1094 * Decrypt it using our private server key and private host key (key
1095 * with larger modulus first).
1097 if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) {
1098 /* Private key has bigger modulus. */
1099 if (BN_num_bits(sensitive_data.private_key->n) <
1100 BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
1101 fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
1102 get_remote_ipaddr(),
1103 BN_num_bits(sensitive_data.private_key->n),
1104 BN_num_bits(sensitive_data.host_key->n),
1105 SSH_KEY_BITS_RESERVED);
1107 rsa_private_decrypt(session_key_int, session_key_int,
1108 sensitive_data.private_key);
1109 rsa_private_decrypt(session_key_int, session_key_int,
1110 sensitive_data.host_key);
1112 /* Host key has bigger modulus (or they are equal). */
1113 if (BN_num_bits(sensitive_data.host_key->n) <
1114 BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) {
1115 fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d",
1116 get_remote_ipaddr(),
1117 BN_num_bits(sensitive_data.host_key->n),
1118 BN_num_bits(sensitive_data.private_key->n),
1119 SSH_KEY_BITS_RESERVED);
1121 rsa_private_decrypt(session_key_int, session_key_int,
1122 sensitive_data.host_key);
1123 rsa_private_decrypt(session_key_int, session_key_int,
1124 sensitive_data.private_key);
1127 compute_session_id(session_id, check_bytes,
1128 sensitive_data.host_key->n,
1129 sensitive_data.private_key->n);
1132 * Extract session key from the decrypted integer. The key is in the
1133 * least significant 256 bits of the integer; the first byte of the
1134 * key is in the highest bits.
1136 BN_mask_bits(session_key_int, sizeof(session_key) * 8);
1137 len = BN_num_bytes(session_key_int);
1138 if (len < 0 || len > sizeof(session_key))
1139 fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d",
1140 get_remote_ipaddr(),
1141 len, sizeof(session_key));
1142 memset(session_key, 0, sizeof(session_key));
1143 BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
1145 /* Xor the first 16 bytes of the session key with the session id. */
1146 for (i = 0; i < 16; i++)
1147 session_key[i] ^= session_id[i];
1149 /* Destroy the decrypted integer. It is no longer needed. */
1150 BN_clear_free(session_key_int);
1152 /* Set the session key. From this on all communications will be encrypted. */
1153 packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
1155 /* Destroy our copy of the session key. It is no longer needed. */
1156 memset(session_key, 0, sizeof(session_key));
1158 debug("Received session key; encryption turned on.");
1160 /* Send an acknowledgement packet. Note that this packet is sent encrypted. */
1161 packet_start(SSH_SMSG_SUCCESS);
1163 packet_write_wait();
1165 /* Get the name of the user that we wish to log in as. */
1166 packet_read_expect(&plen, SSH_CMSG_USER);
1168 /* Get the user name. */
1169 user = packet_get_string(&ulen);
1170 packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
1172 /* Destroy the private and public keys. They will no longer be needed. */
1173 RSA_free(public_key);
1174 RSA_free(sensitive_data.private_key);
1175 RSA_free(sensitive_data.host_key);
1177 setproctitle("%s", user);
1178 /* Do the authentication. */
1179 do_authentication(user);
1183 * Check if the user is allowed to log in via ssh. If user is listed in
1184 * DenyUsers or user's primary group is listed in DenyGroups, false will
1185 * be returned. If AllowUsers isn't empty and user isn't listed there, or
1186 * if AllowGroups isn't empty and user isn't listed there, false will be
1187 * returned. Otherwise true is returned.
1188 * XXX This function should also check if user has a valid shell
1191 allowed_user(struct passwd * pw)
1196 /* Shouldn't be called if pw is NULL, but better safe than sorry... */
1200 /* XXX Should check for valid login shell */
1202 /* Return false if user is listed in DenyUsers */
1203 if (options.num_deny_users > 0) {
1206 for (i = 0; i < options.num_deny_users; i++)
1207 if (match_pattern(pw->pw_name, options.deny_users[i]))
1210 /* Return false if AllowUsers isn't empty and user isn't listed there */
1211 if (options.num_allow_users > 0) {
1214 for (i = 0; i < options.num_allow_users; i++)
1215 if (match_pattern(pw->pw_name, options.allow_users[i]))
1217 /* i < options.num_allow_users iff we break for loop */
1218 if (i >= options.num_allow_users)
1221 /* Get the primary group name if we need it. Return false if it fails */
1222 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
1223 grp = getgrgid(pw->pw_gid);
1227 /* Return false if user's group is listed in DenyGroups */
1228 if (options.num_deny_groups > 0) {
1231 for (i = 0; i < options.num_deny_groups; i++)
1232 if (match_pattern(grp->gr_name, options.deny_groups[i]))
1236 * Return false if AllowGroups isn't empty and user's group
1237 * isn't listed there
1239 if (options.num_allow_groups > 0) {
1242 for (i = 0; i < options.num_allow_groups; i++)
1243 if (match_pattern(grp->gr_name, options.allow_groups[i]))
1245 /* i < options.num_allow_groups iff we break for
1247 if (i >= options.num_allow_groups)
1251 /* We found no reason not to let this user try to log on... */
1256 * Performs authentication of an incoming connection. Session key has already
1257 * been exchanged and encryption is enabled. User is the user name to log
1258 * in as (received from the client).
1261 do_authentication(char *user)
1263 struct passwd *pw, pwcopy;
1266 /* If machine has AFS, set process authentication group. */
1273 /* Verify that the user is a valid user. */
1274 pw = getpwnam(user);
1275 if (!pw || !allowed_user(pw))
1276 do_fake_authloop(user);
1278 /* Take a copy of the returned structure. */
1279 memset(&pwcopy, 0, sizeof(pwcopy));
1280 pwcopy.pw_name = xstrdup(pw->pw_name);
1281 pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
1282 pwcopy.pw_uid = pw->pw_uid;
1283 pwcopy.pw_gid = pw->pw_gid;
1284 pwcopy.pw_dir = xstrdup(pw->pw_dir);
1285 pwcopy.pw_shell = xstrdup(pw->pw_shell);
1292 debug("Starting up PAM with username \"%.200s\"", pw->pw_name);
1294 pam_retval = pam_start("sshd", pw->pw_name, &conv, (pam_handle_t**)&pamh);
1295 if (pam_retval != PAM_SUCCESS)
1296 fatal("PAM initialisation failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
1298 fatal_add_cleanup(&pam_cleanup_proc, NULL);
1303 * If we are not running as root, the user must have the same uid as
1306 if (getuid() != 0 && pw->pw_uid != getuid())
1307 packet_disconnect("Cannot change user when server not running as root.");
1309 debug("Attempting authentication for %.100s.", user);
1311 /* If the user has no password, accept authentication immediately. */
1312 if (options.password_authentication &&
1314 (!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
1317 do_pam_auth(pw->pw_name, "")) {
1319 auth_password(pw, "")) {
1320 #endif /* USE_PAM */
1321 /* Authentication with empty password succeeded. */
1322 log("Login for user %s from %.100s, accepted without authentication.",
1323 pw->pw_name, get_remote_ipaddr());
1325 /* Loop until the user has been authenticated or the
1326 connection is closed, do_authloop() returns only if
1327 authentication is successfull */
1331 /* Check if the user is logging in as root and root logins are disallowed. */
1332 if (pw->pw_uid == 0 && !options.permit_root_login) {
1334 log("Root login accepted for forced command.");
1336 packet_disconnect("ROOT LOGIN REFUSED FROM %.200s",
1337 get_canonical_hostname());
1339 /* The user has been authenticated and accepted. */
1340 packet_start(SSH_SMSG_SUCCESS);
1342 packet_write_wait();
1344 /* Perform session preparation. */
1345 do_authenticated(pw);
1348 #define AUTH_FAIL_MAX 6
1349 #define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2)
1350 #define AUTH_FAIL_MSG "Too many authentication failures for %.100s"
1353 * read packets and try to authenticate local user *pw.
1354 * return if authentication is successfull
1357 do_authloop(struct passwd * pw)
1361 BIGNUM *client_host_key_e, *client_host_key_n;
1363 char *client_user = NULL, *password = NULL;
1365 int plen, dlen, nlen, ulen, elen;
1367 void (*authlog) (const char *fmt,...) = verbose;
1369 /* Indicate that authentication is needed. */
1370 packet_start(SSH_SMSG_FAILURE);
1372 packet_write_wait();
1374 for (attempt = 1;; attempt++) {
1375 int authenticated = 0;
1376 strlcpy(user, "", sizeof user);
1378 /* Get a packet from the client. */
1379 type = packet_read(&plen);
1381 /* Process the packet. */
1384 case SSH_CMSG_HAVE_KERBEROS_TGT:
1385 if (!options.kerberos_tgt_passing) {
1386 /* packet_get_all(); */
1387 verbose("Kerberos tgt passing disabled.");
1390 /* Accept Kerberos tgt. */
1391 char *tgt = packet_get_string(&dlen);
1392 packet_integrity_check(plen, 4 + dlen, type);
1393 if (!auth_kerberos_tgt(pw, tgt))
1394 verbose("Kerberos tgt REFUSED for %s", pw->pw_name);
1399 case SSH_CMSG_HAVE_AFS_TOKEN:
1400 if (!options.afs_token_passing || !k_hasafs()) {
1401 /* packet_get_all(); */
1402 verbose("AFS token passing disabled.");
1405 /* Accept AFS token. */
1406 char *token_string = packet_get_string(&dlen);
1407 packet_integrity_check(plen, 4 + dlen, type);
1408 if (!auth_afs_token(pw, token_string))
1409 verbose("AFS token REFUSED for %s", pw->pw_name);
1410 xfree(token_string);
1415 case SSH_CMSG_AUTH_KERBEROS:
1416 if (!options.kerberos_authentication) {
1417 /* packet_get_all(); */
1418 verbose("Kerberos authentication disabled.");
1421 /* Try Kerberos v4 authentication. */
1423 char *tkt_user = NULL;
1424 char *kdata = packet_get_string((unsigned int *) &auth.length);
1425 packet_integrity_check(plen, 4 + auth.length, type);
1427 if (auth.length < MAX_KTXT_LEN)
1428 memcpy(auth.dat, kdata, auth.length);
1431 authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
1433 if (authenticated) {
1434 snprintf(user, sizeof user, " tktuser %s", tkt_user);
1441 case SSH_CMSG_AUTH_RHOSTS:
1442 if (!options.rhosts_authentication) {
1443 verbose("Rhosts authentication disabled.");
1447 * Get client user name. Note that we just have to
1448 * trust the client; this is one reason why rhosts
1449 * authentication is insecure. (Another is
1450 * IP-spoofing on a local network.)
1452 client_user = packet_get_string(&ulen);
1453 packet_integrity_check(plen, 4 + ulen, type);
1455 /* Try to authenticate using /etc/hosts.equiv and
1457 authenticated = auth_rhosts(pw, client_user);
1459 snprintf(user, sizeof user, " ruser %s", client_user);
1462 #endif /* USE_PAM */
1465 case SSH_CMSG_AUTH_RHOSTS_RSA:
1466 if (!options.rhosts_rsa_authentication) {
1467 verbose("Rhosts with RSA authentication disabled.");
1471 * Get client user name. Note that we just have to
1472 * trust the client; root on the client machine can
1473 * claim to be any user.
1475 client_user = packet_get_string(&ulen);
1477 /* Get the client host key. */
1478 client_host_key_e = BN_new();
1479 client_host_key_n = BN_new();
1480 bits = packet_get_int();
1481 packet_get_bignum(client_host_key_e, &elen);
1482 packet_get_bignum(client_host_key_n, &nlen);
1484 if (bits != BN_num_bits(client_host_key_n))
1485 error("Warning: keysize mismatch for client_host_key: "
1486 "actual %d, announced %d", BN_num_bits(client_host_key_n), bits);
1487 packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
1489 authenticated = auth_rhosts_rsa(pw, client_user,
1490 client_host_key_e, client_host_key_n);
1491 BN_clear_free(client_host_key_e);
1492 BN_clear_free(client_host_key_n);
1494 snprintf(user, sizeof user, " ruser %s", client_user);
1497 #endif /* USE_PAM */
1500 case SSH_CMSG_AUTH_RSA:
1501 if (!options.rsa_authentication) {
1502 verbose("RSA authentication disabled.");
1505 /* RSA authentication requested. */
1507 packet_get_bignum(n, &nlen);
1508 packet_integrity_check(plen, nlen, type);
1509 authenticated = auth_rsa(pw, n);
1513 case SSH_CMSG_AUTH_PASSWORD:
1514 if (!options.password_authentication) {
1515 verbose("Password authentication disabled.");
1519 * Read user password. It is in plain text, but was
1520 * transmitted over the encrypted channel so it is
1521 * not visible to an outside observer.
1523 password = packet_get_string(&dlen);
1524 packet_integrity_check(plen, 4 + dlen, type);
1527 /* Do PAM auth with password */
1528 authenticated = do_pam_auth(pw->pw_name, password);
1530 /* Try authentication with the password. */
1531 authenticated = auth_password(pw, password);
1532 #endif /* USE_PAM */
1533 memset(password, 0, strlen(password));
1538 case SSH_CMSG_AUTH_TIS:
1539 debug("rcvd SSH_CMSG_AUTH_TIS");
1540 if (options.skey_authentication == 1) {
1541 char *skeyinfo = skey_keyinfo(pw->pw_name);
1542 if (skeyinfo == NULL) {
1543 debug("generating fake skeyinfo for %.100s.", pw->pw_name);
1544 skeyinfo = skey_fake_keyinfo(pw->pw_name);
1546 if (skeyinfo != NULL) {
1547 /* we send our s/key- in tis-challenge messages */
1548 debug("sending challenge '%s'", skeyinfo);
1549 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1550 packet_put_string(skeyinfo, strlen(skeyinfo));
1552 packet_write_wait();
1557 case SSH_CMSG_AUTH_TIS_RESPONSE:
1558 debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
1559 if (options.skey_authentication == 1) {
1560 char *response = packet_get_string(&dlen);
1561 debug("skey response == '%s'", response);
1562 packet_integrity_check(plen, 4 + dlen, type);
1563 authenticated = (skey_haskey(pw->pw_name) == 0 &&
1564 skey_passcheck(pw->pw_name, response) != -1);
1569 case SSH_CMSG_AUTH_TIS:
1570 /* TIS Authentication is unsupported */
1571 log("TIS authentication unsupported.");
1577 * Any unknown messages will be ignored (and failure
1578 * returned) during authentication.
1580 log("Unknown message during authentication: type %d", type);
1584 /* Raise logging level */
1585 if (authenticated ||
1586 attempt == AUTH_FAIL_LOG ||
1587 type == SSH_CMSG_AUTH_PASSWORD)
1590 authlog("%s %s for %.200s from %.200s port %d%s",
1591 authenticated ? "Accepted" : "Failed",
1593 pw->pw_uid == 0 ? "ROOT" : pw->pw_name,
1594 get_remote_ipaddr(),
1602 if (attempt > AUTH_FAIL_MAX)
1603 packet_disconnect(AUTH_FAIL_MSG, pw->pw_name);
1605 if (authenticated) {
1606 do_pam_account(pw->pw_name, client_user);
1608 if (client_user != NULL)
1614 if (attempt > AUTH_FAIL_MAX) {
1615 if (client_user != NULL)
1618 packet_disconnect(AUTH_FAIL_MSG, pw->pw_name);
1620 #endif /* USE_PAM */
1622 /* Send a message indicating that the authentication attempt failed. */
1623 packet_start(SSH_SMSG_FAILURE);
1625 packet_write_wait();
1630 * The user does not exist or access is denied,
1631 * but fake indication that authentication is needed.
1634 do_fake_authloop(char *user)
1638 log("Faking authloop for illegal user %.200s from %.200s port %d",
1640 get_remote_ipaddr(),
1643 /* Indicate that authentication is needed. */
1644 packet_start(SSH_SMSG_FAILURE);
1646 packet_write_wait();
1649 * Keep reading packets, and always respond with a failure. This is
1650 * to avoid disclosing whether such a user really exists.
1652 for (attempt = 1;; attempt++) {
1653 /* Read a packet. This will not return if the client disconnects. */
1655 int type = packet_read(&plen);
1658 char *password, *skeyinfo;
1659 /* Try to send a fake s/key challenge. */
1660 if (options.skey_authentication == 1 &&
1661 (skeyinfo = skey_fake_keyinfo(user)) != NULL) {
1662 if (type == SSH_CMSG_AUTH_TIS) {
1663 packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
1664 packet_put_string(skeyinfo, strlen(skeyinfo));
1666 packet_write_wait();
1668 } else if (type == SSH_CMSG_AUTH_PASSWORD &&
1669 options.password_authentication &&
1670 (password = packet_get_string(&dlen)) != NULL &&
1672 strncasecmp(password, "s/key", 5) == 0 ) {
1673 packet_send_debug(skeyinfo);
1677 if (attempt > AUTH_FAIL_MAX)
1678 packet_disconnect(AUTH_FAIL_MSG, user);
1681 * Send failure. This should be indistinguishable from a
1682 * failed authentication.
1684 packet_start(SSH_SMSG_FAILURE);
1686 packet_write_wait();
1694 * Remove local Xauthority file.
1697 xauthfile_cleanup_proc(void *ignore)
1699 debug("xauthfile_cleanup_proc called");
1701 if (xauthfile != NULL) {
1709 * Prepares for an interactive session. This is called after the user has
1710 * been successfully authenticated. During this message exchange, pseudo
1711 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
1712 * are requested, etc.
1715 do_authenticated(struct passwd * pw)
1718 int compression_level = 0, enable_compression_after_reply = 0;
1719 int have_pty = 0, ptyfd = -1, ttyfd = -1, xauthfd = -1;
1720 int row, col, xpixel, ypixel, screen;
1722 char *command, *term = NULL, *display = NULL, *proto = NULL,
1730 * Cancel the alarm we set to limit the time taken for
1736 * Inform the channel mechanism that we are the server side and that
1737 * the client may request to connect to any port at all. (The user
1738 * could do it anyway, and we wouldn\'t know what is permitted except
1739 * by the client telling us, so we can equally well trust the client
1740 * not to request anything bogus.)
1742 channel_permit_all_opens();
1745 * We stay in this loop until the client requests to execute a shell
1751 /* Get a packet from the client. */
1752 type = packet_read(&plen);
1754 /* Process the packet. */
1756 case SSH_CMSG_REQUEST_COMPRESSION:
1757 packet_integrity_check(plen, 4, type);
1758 compression_level = packet_get_int();
1759 if (compression_level < 1 || compression_level > 9) {
1760 packet_send_debug("Received illegal compression level %d.",
1764 /* Enable compression after we have responded with SUCCESS. */
1765 enable_compression_after_reply = 1;
1768 case SSH_CMSG_REQUEST_PTY:
1770 debug("Allocating a pty not permitted for this authentication.");
1774 packet_disconnect("Protocol error: you already have a pty.");
1776 debug("Allocating pty.");
1778 /* Allocate a pty and open it. */
1779 if (!pty_allocate(&ptyfd, &ttyfd, ttyname,
1781 error("Failed to allocate pty.");
1784 /* Determine the group to make the owner of the tty. */
1785 grp = getgrnam("tty");
1787 tty_gid = grp->gr_gid;
1788 tty_mode = S_IRUSR | S_IWUSR | S_IWGRP;
1790 tty_gid = pw->pw_gid;
1791 tty_mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
1794 /* Change ownership of the tty. */
1795 if (chown(ttyname, pw->pw_uid, tty_gid) < 0)
1796 fatal("chown(%.100s, %d, %d) failed: %.100s",
1797 ttyname, pw->pw_uid, tty_gid, strerror(errno));
1798 if (chmod(ttyname, tty_mode) < 0)
1799 fatal("chmod(%.100s, 0%o) failed: %.100s",
1800 ttyname, tty_mode, strerror(errno));
1802 /* Get TERM from the packet. Note that the value may be of arbitrary length. */
1803 term = packet_get_string(&dlen);
1804 packet_integrity_check(dlen, strlen(term), type);
1805 /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */
1806 /* Remaining bytes */
1807 n_bytes = plen - (4 + dlen + 4 * 4);
1809 if (strcmp(term, "") == 0)
1812 /* Get window size from the packet. */
1813 row = packet_get_int();
1814 col = packet_get_int();
1815 xpixel = packet_get_int();
1816 ypixel = packet_get_int();
1817 pty_change_window_size(ptyfd, row, col, xpixel, ypixel);
1819 /* Get tty modes from the packet. */
1820 tty_parse_modes(ttyfd, &n_bytes);
1821 packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);
1823 /* Indicate that we now have a pty. */
1827 /* do the pam_open_session since we have the pty */
1828 do_pam_session(pw->pw_name,ttyname);
1829 #endif /* USE_PAM */
1833 case SSH_CMSG_X11_REQUEST_FORWARDING:
1834 if (!options.x11_forwarding) {
1835 packet_send_debug("X11 forwarding disabled in server configuration file.");
1839 if (no_x11_forwarding_flag) {
1840 packet_send_debug("X11 forwarding not permitted for this authentication.");
1843 debug("Received request for X11 forwarding with auth spoofing.");
1845 packet_disconnect("Protocol error: X11 display already set.");
1847 int proto_len, data_len;
1848 proto = packet_get_string(&proto_len);
1849 data = packet_get_string(&data_len);
1850 packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type);
1852 if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER)
1853 screen = packet_get_int();
1856 display = x11_create_display_inet(screen, options.x11_display_offset);
1860 /* Setup to always have a local .Xauthority. */
1861 xauthfile = xmalloc(MAXPATHLEN);
1862 snprintf(xauthfile, MAXPATHLEN, "/tmp/XauthXXXXXX");
1864 if ((xauthfd = mkstemp(xauthfile)) != -1) {
1865 fchown(xauthfd, pw->pw_uid, pw->pw_gid);
1867 fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
1873 #else /* XAUTH_PATH */
1874 packet_send_debug("No xauth program; cannot forward with spoofing.");
1876 #endif /* XAUTH_PATH */
1878 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
1879 if (no_agent_forwarding_flag) {
1880 debug("Authentication agent forwarding not permitted for this authentication.");
1883 debug("Received authentication agent forwarding request.");
1884 auth_input_request_forwarding(pw);
1887 case SSH_CMSG_PORT_FORWARD_REQUEST:
1888 if (no_port_forwarding_flag) {
1889 debug("Port forwarding not permitted for this authentication.");
1892 debug("Received TCP/IP port forwarding request.");
1893 channel_input_port_forward_request(pw->pw_uid == 0);
1896 case SSH_CMSG_MAX_PACKET_SIZE:
1897 if (packet_set_maxsize(packet_get_int()) < 0)
1901 case SSH_CMSG_EXEC_SHELL:
1902 /* Set interactive/non-interactive mode. */
1903 packet_set_interactive(have_pty || display != NULL,
1904 options.keepalives);
1906 if (forced_command != NULL)
1907 goto do_forced_command;
1908 debug("Forking shell.");
1909 packet_integrity_check(plen, 0, type);
1911 do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1913 do_exec_no_pty(NULL, pw, display, proto, data);
1916 case SSH_CMSG_EXEC_CMD:
1917 /* Set interactive/non-interactive mode. */
1918 packet_set_interactive(have_pty || display != NULL,
1919 options.keepalives);
1921 if (forced_command != NULL)
1922 goto do_forced_command;
1923 /* Get command from the packet. */
1926 command = packet_get_string(&dlen);
1927 debug("Executing command '%.500s'", command);
1928 packet_integrity_check(plen, 4 + dlen, type);
1931 do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1933 do_exec_no_pty(command, pw, display, proto, data);
1939 * Any unknown messages in this phase are ignored,
1940 * and a failure message is returned.
1942 log("Unknown packet type received after authentication: %d", type);
1946 /* The request was successfully processed. */
1947 packet_start(SSH_SMSG_SUCCESS);
1949 packet_write_wait();
1951 /* Enable compression now that we have replied if appropriate. */
1952 if (enable_compression_after_reply) {
1953 enable_compression_after_reply = 0;
1954 packet_start_compression(compression_level);
1959 /* The request failed. */
1960 packet_start(SSH_SMSG_FAILURE);
1962 packet_write_wait();
1967 * There is a forced command specified for this login.
1970 debug("Executing forced command: %.900s", forced_command);
1972 do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
1974 do_exec_no_pty(forced_command, pw, display, proto, data);
1980 * This is called to fork and execute a command when we have no tty. This
1981 * will call do_child from the child, and server_loop from the parent after
1982 * setting up file descriptors and such.
1985 do_exec_no_pty(const char *command, struct passwd * pw,
1986 const char *display, const char *auth_proto,
1987 const char *auth_data)
1992 int pin[2], pout[2], perr[2];
1993 /* Allocate pipes for communicating with the program. */
1994 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
1995 packet_disconnect("Could not create pipes: %.100s",
1997 #else /* USE_PIPES */
1998 int inout[2], err[2];
1999 /* Uses socket pairs to communicate with the program. */
2000 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
2001 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
2002 packet_disconnect("Could not create socket pairs: %.100s",
2004 #endif /* USE_PIPES */
2006 setproctitle("%s@notty", pw->pw_name);
2008 /* Fork the child. */
2009 if ((pid = fork()) == 0) {
2010 /* Child. Reinitialize the log since the pid has changed. */
2011 log_init(av0, options.log_level, options.log_facility, log_stderr);
2014 * Create a new session and process group since the 4.4BSD
2015 * setlogin() affects the entire process group.
2018 error("setsid failed: %.100s", strerror(errno));
2022 * Redirect stdin. We close the parent side of the socket
2023 * pair, and make the child side the standard input.
2026 if (dup2(pin[0], 0) < 0)
2027 perror("dup2 stdin");
2030 /* Redirect stdout. */
2032 if (dup2(pout[1], 1) < 0)
2033 perror("dup2 stdout");
2036 /* Redirect stderr. */
2038 if (dup2(perr[1], 2) < 0)
2039 perror("dup2 stderr");
2041 #else /* USE_PIPES */
2043 * Redirect stdin, stdout, and stderr. Stdin and stdout will
2044 * use the same socket, as some programs (particularly rdist)
2045 * seem to depend on it.
2049 if (dup2(inout[0], 0) < 0) /* stdin */
2050 perror("dup2 stdin");
2051 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
2052 perror("dup2 stdout");
2053 if (dup2(err[0], 2) < 0) /* stderr */
2054 perror("dup2 stderr");
2055 #endif /* USE_PIPES */
2057 /* Do processing for the child (exec command etc). */
2058 do_child(command, pw, NULL, display, auth_proto, auth_data, NULL);
2062 packet_disconnect("fork failed: %.100s", strerror(errno));
2064 /* We are the parent. Close the child sides of the pipes. */
2069 /* Enter the interactive session. */
2070 server_loop(pid, pin[1], pout[0], perr[0]);
2071 /* server_loop has closed pin[1], pout[1], and perr[1]. */
2072 #else /* USE_PIPES */
2073 /* We are the parent. Close the child sides of the socket pairs. */
2078 * Enter the interactive session. Note: server_loop must be able to
2079 * handle the case that fdin and fdout are the same.
2081 server_loop(pid, inout[1], inout[1], err[1]);
2082 /* server_loop has closed inout[1] and err[1]. */
2083 #endif /* USE_PIPES */
2086 struct pty_cleanup_context {
2087 const char *ttyname;
2092 * Function to perform cleanup if we get aborted abnormally (e.g., due to a
2093 * dropped connection).
2096 pty_cleanup_proc(void *context)
2098 struct pty_cleanup_context *cu = context;
2100 debug("pty_cleanup_proc called");
2102 /* Record that the user has logged out. */
2103 record_logout(cu->pid, cu->ttyname);
2105 /* Release the pseudo-tty. */
2106 pty_release(cu->ttyname);
2110 * This is called to fork and execute a command when we have a tty. This
2111 * will call do_child from the child, and server_loop from the parent after
2112 * setting up file descriptors, controlling tty, updating wtmp, utmp,
2113 * lastlog, and other such operations.
2116 do_exec_pty(const char *command, int ptyfd, int ttyfd,
2117 const char *ttyname, struct passwd * pw, const char *term,
2118 const char *display, const char *auth_proto,
2119 const char *auth_data)
2122 const char *hostname;
2123 time_t last_login_time;
2124 char buf[100], *time_string;
2129 struct sockaddr_in from;
2131 struct pty_cleanup_context cleanup_context;
2133 /* Get remote host name. */
2134 hostname = get_canonical_hostname();
2137 * Get the time when the user last logged in. Buf will be set to
2138 * contain the hostname the last login was from.
2140 if (!options.use_login) {
2141 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
2144 setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1);
2146 /* Fork the child. */
2147 if ((pid = fork()) == 0) {
2150 /* Child. Reinitialize the log because the pid has
2152 log_init(av0, options.log_level, options.log_facility, log_stderr);
2154 /* Close the master side of the pseudo tty. */
2157 /* Make the pseudo tty our controlling tty. */
2158 pty_make_controlling_tty(&ttyfd, ttyname);
2160 /* Redirect stdin from the pseudo tty. */
2161 if (dup2(ttyfd, fileno(stdin)) < 0)
2162 error("dup2 stdin failed: %.100s", strerror(errno));
2164 /* Redirect stdout to the pseudo tty. */
2165 if (dup2(ttyfd, fileno(stdout)) < 0)
2166 error("dup2 stdin failed: %.100s", strerror(errno));
2168 /* Redirect stderr to the pseudo tty. */
2169 if (dup2(ttyfd, fileno(stderr)) < 0)
2170 error("dup2 stdin failed: %.100s", strerror(errno));
2172 /* Close the extra descriptor for the pseudo tty. */
2176 * Get IP address of client. This is needed because we want
2177 * to record where the user logged in from. If the
2178 * connection is not a socket, let the ip address be 0.0.0.0.
2180 memset(&from, 0, sizeof(from));
2181 if (packet_get_connection_in() == packet_get_connection_out()) {
2182 fromlen = sizeof(from);
2183 if (getpeername(packet_get_connection_in(),
2184 (struct sockaddr *) & from, &fromlen) < 0) {
2185 debug("getpeername: %.100s", strerror(errno));
2189 /* Record that there was a login on that terminal. */
2190 record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname,
2193 /* Check if .hushlogin exists. */
2194 snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir);
2195 quiet_login = stat(line, &st) >= 0;
2198 /* output the results of the pamconv() */
2199 if (!quiet_login && pamconv_msg != NULL)
2200 fprintf(stderr, pamconv_msg);
2204 * If the user has logged in before, display the time of last
2205 * login. However, don't display anything extra if a command
2206 * has been specified (so that ssh can be used to execute
2207 * commands on a remote machine without users knowing they
2208 * are going to another machine). Login(1) will do this for
2209 * us as well, so check if login(1) is used
2211 if (command == NULL && last_login_time != 0 && !quiet_login &&
2212 !options.use_login) {
2213 /* Convert the date to a string. */
2214 time_string = ctime(&last_login_time);
2215 /* Remove the trailing newline. */
2216 if (strchr(time_string, '\n'))
2217 *strchr(time_string, '\n') = 0;
2218 /* Display the last login time. Host if displayed
2220 if (strcmp(buf, "") == 0)
2221 printf("Last login: %s\r\n", time_string);
2223 printf("Last login: %s from %s\r\n", time_string, buf);
2226 * Print /etc/motd unless a command was specified or printing
2227 * it was disabled in server options or login(1) will be
2228 * used. Note that some machines appear to print it in
2229 * /etc/profile or similar.
2231 if (command == NULL && options.print_motd && !quiet_login &&
2232 !options.use_login) {
2233 /* Print /etc/motd if it exists. */
2234 f = fopen("/etc/motd", "r");
2236 while (fgets(line, sizeof(line), f))
2237 fputs(line, stdout);
2241 /* Do common processing for the child, such as execing the command. */
2242 do_child(command, pw, term, display, auth_proto, auth_data, ttyname);
2246 packet_disconnect("fork failed: %.100s", strerror(errno));
2247 /* Parent. Close the slave side of the pseudo tty. */
2251 * Create another descriptor of the pty master side for use as the
2252 * standard input. We could use the original descriptor, but this
2253 * simplifies code in server_loop. The descriptor is bidirectional.
2257 packet_disconnect("dup failed: %.100s", strerror(errno));
2260 * Add a cleanup function to clear the utmp entry and record logout
2261 * time in case we call fatal() (e.g., the connection gets closed).
2263 cleanup_context.pid = pid;
2264 cleanup_context.ttyname = ttyname;
2265 fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
2267 /* Enter interactive session. */
2268 server_loop(pid, ptyfd, fdout, -1);
2269 /* server_loop has not closed ptyfd and fdout. */
2271 /* Cancel the cleanup function. */
2272 fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
2274 /* Record that the user has logged out. */
2275 record_logout(pid, ttyname);
2277 /* Release the pseudo-tty. */
2278 pty_release(ttyname);
2281 * Close the server side of the socket pairs. We must do this after
2282 * the pty cleanup, so that another process doesn't get this pty
2283 * while we're still cleaning up.
2290 * Sets the value of the given variable in the environment. If the variable
2291 * already exists, its value is overriden.
2294 child_set_env(char ***envp, unsigned int *envsizep, const char *name,
2297 unsigned int i, namelen;
2301 * Find the slot where the value should be stored. If the variable
2302 * already exists, we reuse the slot; otherwise we append a new slot
2303 * at the end of the array, expanding if necessary.
2306 namelen = strlen(name);
2307 for (i = 0; env[i]; i++)
2308 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
2311 /* Reuse the slot. */
2314 /* New variable. Expand if necessary. */
2315 if (i >= (*envsizep) - 1) {
2317 env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
2319 /* Need to set the NULL pointer at end of array beyond the new slot. */
2323 /* Allocate space and format the variable in the appropriate slot. */
2324 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
2325 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
2329 * Reads environment variables from the given file and adds/overrides them
2330 * into the environment. If the file does not exist, this does nothing.
2331 * Otherwise, it must consist of empty lines, comments (line starts with '#')
2332 * and assignments of the form name=value. No other forms are allowed.
2335 read_environment_file(char ***env, unsigned int *envsize,
2336 const char *filename)
2342 f = fopen(filename, "r");
2346 while (fgets(buf, sizeof(buf), f)) {
2347 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
2349 if (!*cp || *cp == '#' || *cp == '\n')
2351 if (strchr(cp, '\n'))
2352 *strchr(cp, '\n') = '\0';
2353 value = strchr(cp, '=');
2354 if (value == NULL) {
2355 fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
2358 /* Replace the equals sign by nul, and advance value to the value string. */
2361 child_set_env(env, envsize, cp, value);
2367 * Performs common processing for the child, such as setting up the
2368 * environment, closing extra file descriptors, setting the user and group
2369 * ids, and executing the command or shell.
2372 do_child(const char *command, struct passwd * pw, const char *term,
2373 const char *display, const char *auth_proto,
2374 const char *auth_data, const char *ttyname)
2376 const char *shell, *cp = NULL;
2379 unsigned int envsize, i;
2381 extern char **environ;
2385 #ifndef USE_PAM /* pam_nologin handles this */
2386 /* Check /etc/nologin. */
2387 f = fopen("/etc/nologin", "r");
2389 /* /etc/nologin exists. Print its contents and exit. */
2390 while (fgets(buf, sizeof(buf), f))
2393 if (pw->pw_uid != 0)
2396 #endif /* USE_PAM */
2398 #ifdef HAVE_SETLOGIN
2399 /* Set login name in the kernel. */
2400 if (setlogin(pw->pw_name) < 0)
2401 error("setlogin failed: %s", strerror(errno));
2402 #endif /* HAVE_SETLOGIN */
2404 /* Set uid, gid, and groups. */
2405 /* Login(1) does this as well, and it needs uid 0 for the "-h"
2406 switch, so we let login(1) to this for us. */
2407 if (!options.use_login) {
2408 if (getuid() == 0 || geteuid() == 0) {
2409 if (setgid(pw->pw_gid) < 0) {
2413 /* Initialize the group list. */
2414 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
2415 perror("initgroups");
2420 /* Permanently switch to the desired uid. */
2421 permanently_set_uid(pw->pw_uid);
2423 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
2424 fatal("Failed to set uids to %d.", (int) pw->pw_uid);
2427 * Get the shell from the password data. An empty shell field is
2428 * legal, and means /bin/sh.
2430 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
2433 /* Try to get AFS tokens for the local cell. */
2437 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
2438 krb_afslog(cell, 0);
2444 /* Initialize the environment. */
2446 env = xmalloc(envsize * sizeof(char *));
2449 if (!options.use_login) {
2450 /* Set basic environment. */
2451 child_set_env(&env, &envsize, "USER", pw->pw_name);
2452 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
2453 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
2454 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
2456 snprintf(buf, sizeof buf, "%.200s/%.50s",
2457 _PATH_MAILDIR, pw->pw_name);
2458 child_set_env(&env, &envsize, "MAIL", buf);
2460 /* Normal systems set SHELL by default. */
2461 child_set_env(&env, &envsize, "SHELL", shell);
2464 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
2466 /* Set custom environment options from RSA authentication. */
2467 while (custom_environment) {
2468 struct envstring *ce = custom_environment;
2471 for (i = 0; s[i] != '=' && s[i]; i++);
2474 child_set_env(&env, &envsize, s, s + i + 1);
2476 custom_environment = ce->next;
2481 snprintf(buf, sizeof buf, "%.50s %d %d",
2482 get_remote_ipaddr(), get_remote_port(), options.port);
2483 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
2486 child_set_env(&env, &envsize, "SSH_TTY", ttyname);
2488 child_set_env(&env, &envsize, "TERM", term);
2490 child_set_env(&env, &envsize, "DISPLAY", display);
2494 extern char *ticket;
2497 child_set_env(&env, &envsize, "KRBTKFILE", ticket);
2502 /* Pull in any environment variables that may have been set by PAM. */
2504 char *equals, var_name[512], var_val[512];
2505 char **pam_env = pam_getenvlist((pam_handle_t *)pamh);
2507 for(i = 0; pam_env && pam_env[i]; i++) {
2508 equals = strstr(pam_env[i], "=");
2509 if ((strlen(pam_env[i]) < (sizeof(var_name) - 1)) && (equals != NULL))
2511 debug("PAM environment: %s=%s", var_name, var_val);
2512 memset(var_name, '\0', sizeof(var_name));
2513 memset(var_val, '\0', sizeof(var_val));
2514 strncpy(var_name, pam_env[i], equals - pam_env[i]);
2515 strcpy(var_val, equals + 1);
2516 child_set_env(&env, &envsize, var_name, var_val);
2520 #endif /* USE_PAM */
2523 child_set_env(&env, &envsize, "XAUTHORITY", xauthfile);
2525 if (auth_get_socket_name() != NULL)
2526 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
2527 auth_get_socket_name());
2529 /* read $HOME/.ssh/environment. */
2530 if (!options.use_login) {
2531 snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir);
2532 read_environment_file(&env, &envsize, buf);
2535 /* dump the environment */
2536 fprintf(stderr, "Environment:\n");
2537 for (i = 0; env[i]; i++)
2538 fprintf(stderr, " %.200s\n", env[i]);
2541 * Close the connection descriptors; note that this is the child, and
2542 * the server will still have the socket open, and it is important
2543 * that we do not shutdown it. Note that the descriptors cannot be
2544 * closed before building the environment, as we call
2545 * get_remote_ipaddr there.
2547 if (packet_get_connection_in() == packet_get_connection_out())
2548 close(packet_get_connection_in());
2550 close(packet_get_connection_in());
2551 close(packet_get_connection_out());
2554 * Close all descriptors related to channels. They will still remain
2555 * open in the parent.
2557 /* XXX better use close-on-exec? -markus */
2558 channel_close_all();
2561 * Close any extra file descriptors. Note that there may still be
2562 * descriptors left by system functions. They will be closed later.
2568 * Close any extra open file descriptors so that we don\'t have them
2569 * hanging around in clients. Note that we want to do this after
2570 * initgroups, because at least on Solaris 2.3 it leaves file
2573 for (i = 3; i < 64; i++)
2576 /* Change current directory to the user\'s home directory. */
2577 if (chdir(pw->pw_dir) < 0)
2578 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
2579 pw->pw_dir, strerror(errno));
2582 * Must take new environment into use so that .ssh/rc, /etc/sshrc and
2583 * xauth are run in the proper environment.
2588 * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
2591 if (!options.use_login) {
2592 if (stat(SSH_USER_RC, &st) >= 0) {
2594 fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC);
2596 f = popen("/bin/sh " SSH_USER_RC, "w");
2598 if (auth_proto != NULL && auth_data != NULL)
2599 fprintf(f, "%s %s\n", auth_proto, auth_data);
2602 fprintf(stderr, "Could not run %s\n", SSH_USER_RC);
2603 } else if (stat(SSH_SYSTEM_RC, &st) >= 0) {
2605 fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC);
2607 f = popen("/bin/sh " SSH_SYSTEM_RC, "w");
2609 if (auth_proto != NULL && auth_data != NULL)
2610 fprintf(f, "%s %s\n", auth_proto, auth_data);
2613 fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC);
2617 /* Add authority data to .Xauthority if appropriate. */
2618 if (auth_proto != NULL && auth_data != NULL) {
2620 fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n",
2621 XAUTH_PATH, display, auth_proto, auth_data);
2623 f = popen(XAUTH_PATH " -q -", "w");
2625 fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data);
2628 fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH);
2631 #endif /* XAUTH_PATH */
2633 /* Get the last component of the shell name. */
2634 cp = strrchr(shell, '/');
2641 * If we have no command, execute the shell. In this case, the shell
2642 * name to be passed in argv[0] is preceded by '-' to indicate that
2643 * this is a login shell.
2646 if (!options.use_login) {
2650 * Check for mail if we have a tty and it was enabled
2651 * in server options.
2653 if (ttyname && options.check_mail) {
2655 struct stat mailstat;
2656 mailbox = getenv("MAIL");
2657 if (mailbox != NULL) {
2658 if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0)
2659 printf("No mail.\n");
2660 else if (mailstat.st_mtime < mailstat.st_atime)
2661 printf("You have mail.\n");
2663 printf("You have new mail.\n");
2666 /* Start the shell. Set initial character to '-'. */
2668 strncpy(buf + 1, cp, sizeof(buf) - 1);
2669 buf[sizeof(buf) - 1] = 0;
2671 /* Execute the shell. */
2674 execve(shell, argv, env);
2676 /* Executing the shell failed. */
2681 /* Launch login(1). */
2683 execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(),
2684 "-p", "-f", "--", pw->pw_name, NULL);
2686 /* Login couldn't be executed, die. */
2693 * Execute the command using the user's shell. This uses the -c
2694 * option to execute the command.
2696 argv[0] = (char *) cp;
2698 argv[2] = (char *) command;
2700 execve(shell, argv, env);