2 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * As far as I am concerned, the code I have written for this software
6 * can be used freely for any purpose. Any derived versions of this
7 * software must be clearly marked as such, and if the derived work is
8 * incompatible with the protocol description in the RFC file, it must be
9 * called by a name other than "ssh" or "Secure Shell".
11 * SSH2 support by Markus Friedl.
12 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 RCSID("$OpenBSD: session.c,v 1.128 2002/02/16 00:51:44 markus Exp $");
51 #include "auth-options.h"
52 #include "pathnames.h"
56 #include "serverloop.h"
62 #include <sys/cygwin.h>
63 #define is_winnt (GetVersion() < 0x80000000)
69 typedef struct Session Session;
78 int ptyfd, ttyfd, ptymaster;
79 int row, col, xpixel, ypixel;
88 int single_connection;
96 Session *session_new(void);
97 void session_set_fds(Session *, int, int, int);
98 static void session_pty_cleanup(void *);
99 void session_proctitle(Session *);
100 int session_setup_x11fwd(Session *);
101 void do_exec_pty(Session *, const char *);
102 void do_exec_no_pty(Session *, const char *);
103 void do_exec(Session *, const char *);
104 void do_login(Session *, const char *);
105 #ifdef LOGIN_NEEDS_UTMPX
106 static void do_pre_login(Session *s);
108 void do_child(Session *, const char *);
110 int check_quietlogin(Session *, const char *);
112 static void do_authenticated1(Authctxt *);
113 static void do_authenticated2(Authctxt *);
115 static void session_close(Session *);
116 static int session_pty_req(Session *);
119 extern ServerOptions options;
120 extern char *__progname;
121 extern int log_stderr;
122 extern int debug_flag;
123 extern u_int utmp_len;
124 extern int startup_pipe;
125 extern void destroy_sensitive_data(void);
127 /* original command from peer. */
128 const char *original_command = NULL;
131 #define MAX_SESSIONS 10
132 Session sessions[MAX_SESSIONS];
134 #ifdef WITH_AIXAUTHENTICATE
136 #endif /* WITH_AIXAUTHENTICATE */
138 #ifdef HAVE_LOGIN_CAP
139 static login_cap_t *lc;
143 do_authenticated(Authctxt *authctxt)
146 * Cancel the alarm we set to limit the time taken for
150 if (startup_pipe != -1) {
154 #if defined(HAVE_LOGIN_CAP) && defined(HAVE_PW_CLASS_IN_PASSWD)
155 if ((lc = login_getclass(authctxt->pw->pw_class)) == NULL) {
156 error("unable to get login class");
160 if (auth_approval(NULL, lc, authctxt->pw->pw_name, "ssh") <= 0) {
161 packet_disconnect("Approval failure for %s",
162 authctxt->pw->pw_name);
166 #ifdef WITH_AIXAUTHENTICATE
167 /* We don't have a pty yet, so just label the line as "ssh" */
168 if (loginsuccess(authctxt->user,
169 get_canonical_hostname(options.verify_reverse_mapping),
170 "ssh", &aixloginmsg) < 0)
172 #endif /* WITH_AIXAUTHENTICATE */
174 /* setup the channel layer */
175 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
176 channel_permit_all_opens();
179 do_authenticated2(authctxt);
181 do_authenticated1(authctxt);
183 /* remove agent socket */
184 if (auth_get_socket_name())
185 auth_sock_cleanup_proc(authctxt->pw);
187 if (options.kerberos_ticket_cleanup)
188 krb4_cleanup_proc(authctxt);
191 if (options.kerberos_ticket_cleanup)
192 krb5_cleanup_proc(authctxt);
197 * Prepares for an interactive session. This is called after the user has
198 * been successfully authenticated. During this message exchange, pseudo
199 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
200 * are requested, etc.
203 do_authenticated1(Authctxt *authctxt)
207 int success, type, screen_flag;
208 int compression_level = 0, enable_compression_after_reply = 0;
209 u_int proto_len, data_len, dlen;
212 s->authctxt = authctxt;
213 s->pw = authctxt->pw;
216 * We stay in this loop until the client requests to execute a shell
222 /* Get a packet from the client. */
223 type = packet_read();
225 /* Process the packet. */
227 case SSH_CMSG_REQUEST_COMPRESSION:
228 compression_level = packet_get_int();
230 if (compression_level < 1 || compression_level > 9) {
231 packet_send_debug("Received illegal compression level %d.",
235 /* Enable compression after we have responded with SUCCESS. */
236 enable_compression_after_reply = 1;
240 case SSH_CMSG_REQUEST_PTY:
241 success = session_pty_req(s);
244 case SSH_CMSG_X11_REQUEST_FORWARDING:
245 s->auth_proto = packet_get_string(&proto_len);
246 s->auth_data = packet_get_string(&data_len);
248 screen_flag = packet_get_protocol_flags() &
249 SSH_PROTOFLAG_SCREEN_NUMBER;
250 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
252 if (packet_remaining() == 4) {
254 debug2("Buggy client: "
255 "X11 screen flag missing");
256 s->screen = packet_get_int();
261 success = session_setup_x11fwd(s);
263 xfree(s->auth_proto);
265 s->auth_proto = NULL;
270 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
271 if (no_agent_forwarding_flag || compat13) {
272 debug("Authentication agent forwarding not permitted for this authentication.");
275 debug("Received authentication agent forwarding request.");
276 success = auth_input_request_forwarding(s->pw);
279 case SSH_CMSG_PORT_FORWARD_REQUEST:
280 if (no_port_forwarding_flag) {
281 debug("Port forwarding not permitted for this authentication.");
284 if (!options.allow_tcp_forwarding) {
285 debug("Port forwarding not permitted.");
288 debug("Received TCP/IP port forwarding request.");
289 channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
293 case SSH_CMSG_MAX_PACKET_SIZE:
294 if (packet_set_maxsize(packet_get_int()) > 0)
298 #if defined(AFS) || defined(KRB5)
299 case SSH_CMSG_HAVE_KERBEROS_TGT:
300 if (!options.kerberos_tgt_passing) {
301 verbose("Kerberos TGT passing disabled.");
303 char *kdata = packet_get_string(&dlen);
306 /* XXX - 0x41, see creds_to_radix version */
307 if (kdata[0] != 0x41) {
313 if (auth_krb5_tgt(s->authctxt, &tgt))
316 verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
320 if (auth_krb4_tgt(s->authctxt, kdata))
323 verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
329 #endif /* AFS || KRB5 */
332 case SSH_CMSG_HAVE_AFS_TOKEN:
333 if (!options.afs_token_passing || !k_hasafs()) {
334 verbose("AFS token passing disabled.");
336 /* Accept AFS token. */
337 char *token = packet_get_string(&dlen);
340 if (auth_afs_token(s->authctxt, token))
343 verbose("AFS token refused for %.100s",
350 case SSH_CMSG_EXEC_SHELL:
351 case SSH_CMSG_EXEC_CMD:
352 if (type == SSH_CMSG_EXEC_CMD) {
353 command = packet_get_string(&dlen);
354 debug("Exec command '%.500s'", command);
366 * Any unknown messages in this phase are ignored,
367 * and a failure message is returned.
369 log("Unknown packet type received after authentication: %d", type);
371 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
375 /* Enable compression now that we have replied if appropriate. */
376 if (enable_compression_after_reply) {
377 enable_compression_after_reply = 0;
378 packet_start_compression(compression_level);
384 * This is called to fork and execute a command when we have no tty. This
385 * will call do_child from the child, and server_loop from the parent after
386 * setting up file descriptors and such.
389 do_exec_no_pty(Session *s, const char *command)
394 int pin[2], pout[2], perr[2];
395 /* Allocate pipes for communicating with the program. */
396 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
397 packet_disconnect("Could not create pipes: %.100s",
399 #else /* USE_PIPES */
400 int inout[2], err[2];
401 /* Uses socket pairs to communicate with the program. */
402 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
403 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
404 packet_disconnect("Could not create socket pairs: %.100s",
406 #endif /* USE_PIPES */
408 fatal("do_exec_no_pty: no session");
410 session_proctitle(s);
413 do_pam_session(s->pw->pw_name, NULL);
415 if (is_pam_password_change_required())
416 packet_disconnect("Password change required but no "
420 /* Fork the child. */
421 if ((pid = fork()) == 0) {
422 /* Child. Reinitialize the log since the pid has changed. */
423 log_init(__progname, options.log_level, options.log_facility, log_stderr);
426 * Create a new session and process group since the 4.4BSD
427 * setlogin() affects the entire process group.
430 error("setsid failed: %.100s", strerror(errno));
434 * Redirect stdin. We close the parent side of the socket
435 * pair, and make the child side the standard input.
438 if (dup2(pin[0], 0) < 0)
439 perror("dup2 stdin");
442 /* Redirect stdout. */
444 if (dup2(pout[1], 1) < 0)
445 perror("dup2 stdout");
448 /* Redirect stderr. */
450 if (dup2(perr[1], 2) < 0)
451 perror("dup2 stderr");
453 #else /* USE_PIPES */
455 * Redirect stdin, stdout, and stderr. Stdin and stdout will
456 * use the same socket, as some programs (particularly rdist)
457 * seem to depend on it.
461 if (dup2(inout[0], 0) < 0) /* stdin */
462 perror("dup2 stdin");
463 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
464 perror("dup2 stdout");
465 if (dup2(err[0], 2) < 0) /* stderr */
466 perror("dup2 stderr");
467 #endif /* USE_PIPES */
469 /* Do processing for the child (exec command etc). */
470 do_child(s, command);
475 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
478 packet_disconnect("fork failed: %.100s", strerror(errno));
480 /* Set interactive/non-interactive mode. */
481 packet_set_interactive(s->display != NULL);
483 /* We are the parent. Close the child sides of the pipes. */
489 session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
491 /* Enter the interactive session. */
492 server_loop(pid, pin[1], pout[0], perr[0]);
493 /* server_loop has closed pin[1], pout[0], and perr[0]. */
495 #else /* USE_PIPES */
496 /* We are the parent. Close the child sides of the socket pairs. */
501 * Enter the interactive session. Note: server_loop must be able to
502 * handle the case that fdin and fdout are the same.
505 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
507 server_loop(pid, inout[1], inout[1], err[1]);
508 /* server_loop has closed inout[1] and err[1]. */
510 #endif /* USE_PIPES */
514 * This is called to fork and execute a command when we have a tty. This
515 * will call do_child from the child, and server_loop from the parent after
516 * setting up file descriptors, controlling tty, updating wtmp, utmp,
517 * lastlog, and other such operations.
520 do_exec_pty(Session *s, const char *command)
522 int fdout, ptyfd, ttyfd, ptymaster;
526 fatal("do_exec_pty: no session");
531 do_pam_session(s->pw->pw_name, s->tty);
535 /* Fork the child. */
536 if ((pid = fork()) == 0) {
538 /* Child. Reinitialize the log because the pid has changed. */
539 log_init(__progname, options.log_level, options.log_facility, log_stderr);
540 /* Close the master side of the pseudo tty. */
543 /* Make the pseudo tty our controlling tty. */
544 pty_make_controlling_tty(&ttyfd, s->tty);
546 /* Redirect stdin/stdout/stderr from the pseudo tty. */
547 if (dup2(ttyfd, 0) < 0)
548 error("dup2 stdin: %s", strerror(errno));
549 if (dup2(ttyfd, 1) < 0)
550 error("dup2 stdout: %s", strerror(errno));
551 if (dup2(ttyfd, 2) < 0)
552 error("dup2 stderr: %s", strerror(errno));
554 /* Close the extra descriptor for the pseudo tty. */
557 /* record login, etc. similar to login(1) */
559 if (!(options.use_login && command == NULL))
560 do_login(s, command);
561 # ifdef LOGIN_NEEDS_UTMPX
567 /* Do common processing for the child, such as execing the command. */
568 do_child(s, command);
573 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
576 packet_disconnect("fork failed: %.100s", strerror(errno));
579 /* Parent. Close the slave side of the pseudo tty. */
583 * Create another descriptor of the pty master side for use as the
584 * standard input. We could use the original descriptor, but this
585 * simplifies code in server_loop. The descriptor is bidirectional.
589 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
591 /* we keep a reference to the pty master */
592 ptymaster = dup(ptyfd);
594 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
595 s->ptymaster = ptymaster;
597 /* Enter interactive session. */
598 packet_set_interactive(1);
600 session_set_fds(s, ptyfd, fdout, -1);
602 server_loop(pid, ptyfd, fdout, -1);
603 /* server_loop _has_ closed ptyfd and fdout. */
607 #ifdef LOGIN_NEEDS_UTMPX
609 do_pre_login(Session *s)
612 struct sockaddr_storage from;
613 pid_t pid = getpid();
616 * Get IP address of client. If the connection is not a socket, let
617 * the address be 0.0.0.0.
619 memset(&from, 0, sizeof(from));
620 if (packet_connection_is_on_socket()) {
621 fromlen = sizeof(from);
622 if (getpeername(packet_get_connection_in(),
623 (struct sockaddr *) & from, &fromlen) < 0) {
624 debug("getpeername: %.100s", strerror(errno));
629 record_utmp_only(pid, s->tty, s->pw->pw_name,
630 get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping),
631 (struct sockaddr *)&from);
636 * This is called to fork and execute a command. If another command is
637 * to be forced, execute that instead.
640 do_exec(Session *s, const char *command)
642 if (forced_command) {
643 original_command = command;
644 command = forced_command;
645 debug("Forced command '%.900s'", command);
649 do_exec_pty(s, command);
651 do_exec_no_pty(s, command);
653 original_command = NULL;
657 /* administrative, login(1)-like work */
659 do_login(Session *s, const char *command)
662 char hostname[MAXHOSTNAMELEN];
664 struct sockaddr_storage from;
665 time_t last_login_time;
666 struct passwd * pw = s->pw;
667 pid_t pid = getpid();
670 * Get IP address of client. If the connection is not a socket, let
671 * the address be 0.0.0.0.
673 memset(&from, 0, sizeof(from));
674 if (packet_connection_is_on_socket()) {
675 fromlen = sizeof(from);
676 if (getpeername(packet_get_connection_in(),
677 (struct sockaddr *) & from, &fromlen) < 0) {
678 debug("getpeername: %.100s", strerror(errno));
683 /* Get the time and hostname when the user last logged in. */
684 if (options.print_lastlog) {
686 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
687 hostname, sizeof(hostname));
690 /* Record that there was a login on that tty from the remote host. */
691 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
692 get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping),
693 (struct sockaddr *)&from);
697 * If password change is needed, do it now.
698 * This needs to occur before the ~/.hushlogin check.
700 if (is_pam_password_change_required()) {
701 print_pam_messages();
706 if (check_quietlogin(s, command))
710 if (!is_pam_password_change_required())
711 print_pam_messages();
713 #ifdef WITH_AIXAUTHENTICATE
714 if (aixloginmsg && *aixloginmsg)
715 printf("%s\n", aixloginmsg);
716 #endif /* WITH_AIXAUTHENTICATE */
718 if (options.print_lastlog && last_login_time != 0) {
719 time_string = ctime(&last_login_time);
720 if (strchr(time_string, '\n'))
721 *strchr(time_string, '\n') = 0;
722 if (strcmp(hostname, "") == 0)
723 printf("Last login: %s\r\n", time_string);
725 printf("Last login: %s from %s\r\n", time_string, hostname);
732 * Display the message of the day.
740 if (options.print_motd) {
741 #ifdef HAVE_LOGIN_CAP
742 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
745 f = fopen("/etc/motd", "r");
748 while (fgets(buf, sizeof(buf), f))
757 * Check for quiet login, either .hushlogin or command given.
760 check_quietlogin(Session *s, const char *command)
763 struct passwd *pw = s->pw;
766 /* Return 1 if .hushlogin exists or a command given. */
769 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
770 #ifdef HAVE_LOGIN_CAP
771 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
774 if (stat(buf, &st) >= 0)
781 * Sets the value of the given variable in the environment. If the variable
782 * already exists, its value is overriden.
785 child_set_env(char ***envp, u_int *envsizep, const char *name,
792 * Find the slot where the value should be stored. If the variable
793 * already exists, we reuse the slot; otherwise we append a new slot
794 * at the end of the array, expanding if necessary.
797 namelen = strlen(name);
798 for (i = 0; env[i]; i++)
799 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
802 /* Reuse the slot. */
805 /* New variable. Expand if necessary. */
806 if (i >= (*envsizep) - 1) {
808 env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
810 /* Need to set the NULL pointer at end of array beyond the new slot. */
814 /* Allocate space and format the variable in the appropriate slot. */
815 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
816 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
820 * Reads environment variables from the given file and adds/overrides them
821 * into the environment. If the file does not exist, this does nothing.
822 * Otherwise, it must consist of empty lines, comments (line starts with '#')
823 * and assignments of the form name=value. No other forms are allowed.
826 read_environment_file(char ***env, u_int *envsize,
827 const char *filename)
833 f = fopen(filename, "r");
837 while (fgets(buf, sizeof(buf), f)) {
838 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
840 if (!*cp || *cp == '#' || *cp == '\n')
842 if (strchr(cp, '\n'))
843 *strchr(cp, '\n') = '\0';
844 value = strchr(cp, '=');
846 fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
850 * Replace the equals sign by nul, and advance value to
855 child_set_env(env, envsize, cp, value);
860 void copy_environment(char **source, char ***env, u_int *envsize)
862 char *var_name, *var_val;
868 for(i = 0; source[i] != NULL; i++) {
869 var_name = xstrdup(source[i]);
870 if ((var_val = strstr(var_name, "=")) == NULL) {
876 debug3("Copy environment: %s=%s", var_name, var_val);
877 child_set_env(env, envsize, var_name, var_val);
884 do_setup_env(Session *s, const char *shell)
889 struct passwd *pw = s->pw;
891 /* Initialize the environment. */
893 env = xmalloc(envsize * sizeof(char *));
898 * The Windows environment contains some setting which are
899 * important for a running system. They must not be dropped.
901 copy_environment(environ, &env, &envsize);
904 if (!options.use_login) {
905 /* Set basic environment. */
906 child_set_env(&env, &envsize, "USER", pw->pw_name);
907 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
908 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
909 #ifdef HAVE_LOGIN_CAP
910 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
911 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
912 #else /* HAVE_LOGIN_CAP */
915 * There's no standard path on Windows. The path contains
916 * important components pointing to the system directories,
917 * needed for loading shared libraries. So the path better
918 * remains intact here.
920 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
921 # endif /* HAVE_CYGWIN */
922 #endif /* HAVE_LOGIN_CAP */
924 snprintf(buf, sizeof buf, "%.200s/%.50s",
925 _PATH_MAILDIR, pw->pw_name);
926 child_set_env(&env, &envsize, "MAIL", buf);
928 /* Normal systems set SHELL by default. */
929 child_set_env(&env, &envsize, "SHELL", shell);
932 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
934 /* Set custom environment options from RSA authentication. */
935 if (!options.use_login) {
936 while (custom_environment) {
937 struct envstring *ce = custom_environment;
940 for (i = 0; s[i] != '=' && s[i]; i++)
944 child_set_env(&env, &envsize, s, s + i + 1);
946 custom_environment = ce->next;
952 snprintf(buf, sizeof buf, "%.50s %d %d",
953 get_remote_ipaddr(), get_remote_port(), get_local_port());
954 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
957 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
959 child_set_env(&env, &envsize, "TERM", s->term);
961 child_set_env(&env, &envsize, "DISPLAY", s->display);
962 if (original_command)
963 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
970 if ((cp = getenv("AUTHSTATE")) != NULL)
971 child_set_env(&env, &envsize, "AUTHSTATE", cp);
972 if ((cp = getenv("KRB5CCNAME")) != NULL)
973 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
974 read_environment_file(&env, &envsize, "/etc/environment");
978 if (s->authctxt->krb4_ticket_file)
979 child_set_env(&env, &envsize, "KRBTKFILE",
980 s->authctxt->krb4_ticket_file);
983 if (s->authctxt->krb5_ticket_file)
984 child_set_env(&env, &envsize, "KRB5CCNAME",
985 s->authctxt->krb5_ticket_file);
988 /* Pull in any environment variables that may have been set by PAM. */
989 copy_environment(fetch_pam_environment(), &env, &envsize);
992 if (auth_get_socket_name() != NULL)
993 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
994 auth_get_socket_name());
996 /* read $HOME/.ssh/environment. */
997 if (!options.use_login) {
998 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1000 read_environment_file(&env, &envsize, buf);
1003 /* dump the environment */
1004 fprintf(stderr, "Environment:\n");
1005 for (i = 0; env[i]; i++)
1006 fprintf(stderr, " %.200s\n", env[i]);
1012 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1013 * first in this order).
1016 do_rc_files(Session *s, const char *shell)
1024 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1026 /* ignore _PATH_SSH_USER_RC for subsystems */
1027 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1028 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1029 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1031 fprintf(stderr, "Running %s\n", cmd);
1032 f = popen(cmd, "w");
1035 fprintf(f, "%s %s\n", s->auth_proto,
1039 fprintf(stderr, "Could not run %s\n",
1041 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1043 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1044 _PATH_SSH_SYSTEM_RC);
1045 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1048 fprintf(f, "%s %s\n", s->auth_proto,
1052 fprintf(stderr, "Could not run %s\n",
1053 _PATH_SSH_SYSTEM_RC);
1054 } else if (do_xauth && options.xauth_location != NULL) {
1055 /* Add authority data to .Xauthority if appropriate. */
1058 "Running %.100s add "
1059 "%.100s %.100s %.100s\n",
1060 options.xauth_location, s->auth_display,
1061 s->auth_proto, s->auth_data);
1063 snprintf(cmd, sizeof cmd, "%s -q -",
1064 options.xauth_location);
1065 f = popen(cmd, "w");
1067 fprintf(f, "add %s %s %s\n",
1068 s->auth_display, s->auth_proto,
1072 fprintf(stderr, "Could not run %s\n",
1079 do_nologin(struct passwd *pw)
1084 #ifdef HAVE_LOGIN_CAP
1085 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1086 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1087 _PATH_NOLOGIN), "r");
1090 f = fopen(_PATH_NOLOGIN, "r");
1093 /* /etc/nologin exists. Print its contents and exit. */
1094 while (fgets(buf, sizeof(buf), f))
1101 /* Set login name, uid, gid, and groups. */
1103 do_setusercontext(struct passwd *pw)
1107 #else /* HAVE_CYGWIN */
1108 if (getuid() == 0 || geteuid() == 0) {
1109 #endif /* HAVE_CYGWIN */
1110 #ifdef HAVE_GETUSERATTR
1111 set_limits_from_userattr(pw->pw_name);
1112 #endif /* HAVE_GETUSERATTR */
1113 #ifdef HAVE_LOGIN_CAP
1114 if (setusercontext(lc, pw, pw->pw_uid,
1115 (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1116 perror("unable to set user context");
1120 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1121 /* Sets login uid for accounting */
1122 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1123 error("setluid: %s", strerror(errno));
1124 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1126 if (setlogin(pw->pw_name) < 0)
1127 error("setlogin failed: %s", strerror(errno));
1128 if (setgid(pw->pw_gid) < 0) {
1132 /* Initialize the group list. */
1133 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1134 perror("initgroups");
1140 * PAM credentials may take the form of supplementary groups.
1141 * These will have been wiped by the above initgroups() call.
1142 * Reestablish them here.
1145 # endif /* USE_PAM */
1146 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1147 irix_setusercontext(pw);
1148 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1149 /* Permanently switch to the desired uid. */
1150 permanently_set_uid(pw);
1153 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1154 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1158 * Performs common processing for the child, such as setting up the
1159 * environment, closing extra file descriptors, setting the user and group
1160 * ids, and executing the command or shell.
1163 do_child(Session *s, const char *command)
1165 extern char **environ;
1168 const char *shell, *shell0, *hostname = NULL;
1169 struct passwd *pw = s->pw;
1172 /* remove hostkey from the child's memory */
1173 destroy_sensitive_data();
1175 /* login(1) is only called if we execute the login shell */
1176 if (options.use_login && command != NULL)
1177 options.use_login = 0;
1180 * Login(1) does this as well, and it needs uid 0 for the "-h"
1181 * switch, so we let login(1) to this for us.
1183 if (!options.use_login) {
1185 session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
1186 if (!check_quietlogin(s, command))
1188 #else /* HAVE_OSF_SIA */
1191 aix_usrinfo(pw, s->tty, s->ttyfd);
1193 do_setusercontext(pw);
1194 #endif /* HAVE_OSF_SIA */
1198 * Get the shell from the password data. An empty shell field is
1199 * legal, and means /bin/sh.
1201 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1202 #ifdef HAVE_LOGIN_CAP
1203 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1206 env = do_setup_env(s, shell);
1208 /* we have to stash the hostname before we close our socket. */
1209 if (options.use_login)
1210 hostname = get_remote_name_or_ip(utmp_len,
1211 options.verify_reverse_mapping);
1213 * Close the connection descriptors; note that this is the child, and
1214 * the server will still have the socket open, and it is important
1215 * that we do not shutdown it. Note that the descriptors cannot be
1216 * closed before building the environment, as we call
1217 * get_remote_ipaddr there.
1219 if (packet_get_connection_in() == packet_get_connection_out())
1220 close(packet_get_connection_in());
1222 close(packet_get_connection_in());
1223 close(packet_get_connection_out());
1226 * Close all descriptors related to channels. They will still remain
1227 * open in the parent.
1229 /* XXX better use close-on-exec? -markus */
1230 channel_close_all();
1233 * Close any extra file descriptors. Note that there may still be
1234 * descriptors left by system functions. They will be closed later.
1239 * Close any extra open file descriptors so that we don\'t have them
1240 * hanging around in clients. Note that we want to do this after
1241 * initgroups, because at least on Solaris 2.3 it leaves file
1244 for (i = 3; i < 64; i++)
1248 * Must take new environment into use so that .ssh/rc,
1249 * /etc/ssh/sshrc and xauth are run in the proper environment.
1254 /* Try to get AFS tokens for the local cell. */
1258 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1259 krb_afslog(cell, 0);
1265 /* Change current directory to the user\'s home directory. */
1266 if (chdir(pw->pw_dir) < 0) {
1267 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1268 pw->pw_dir, strerror(errno));
1269 #ifdef HAVE_LOGIN_CAP
1270 if (login_getcapbool(lc, "requirehome", 0))
1275 if (!options.use_login)
1276 do_rc_files(s, shell);
1278 /* restore SIGPIPE for child */
1279 signal(SIGPIPE, SIG_DFL);
1281 if (options.use_login) {
1282 /* Launch login(1). */
1284 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1285 #ifdef LOGIN_NEEDS_TERM
1286 (s->term ? s->term : "unknown"),
1287 #endif /* LOGIN_NEEDS_TERM */
1288 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1290 /* Login couldn't be executed, die. */
1296 /* Get the last component of the shell name. */
1297 if ((shell0 = strrchr(shell, '/')) != NULL)
1303 * If we have no command, execute the shell. In this case, the shell
1304 * name to be passed in argv[0] is preceded by '-' to indicate that
1305 * this is a login shell.
1310 /* Start the shell. Set initial character to '-'. */
1313 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1314 >= sizeof(argv0) - 1) {
1320 /* Execute the shell. */
1323 execve(shell, argv, env);
1325 /* Executing the shell failed. */
1330 * Execute the command using the user's shell. This uses the -c
1331 * option to execute the command.
1333 argv[0] = (char *) shell0;
1335 argv[2] = (char *) command;
1337 execve(shell, argv, env);
1346 static int did_init = 0;
1348 debug("session_new: init");
1349 for (i = 0; i < MAX_SESSIONS; i++) {
1350 sessions[i].used = 0;
1354 for (i = 0; i < MAX_SESSIONS; i++) {
1355 Session *s = &sessions[i];
1357 memset(s, 0, sizeof(*s));
1363 debug("session_new: session %d", i);
1374 for (i = 0; i < MAX_SESSIONS; i++) {
1375 Session *s = &sessions[i];
1376 debug("dump: used %d session %d %p channel %d pid %d",
1386 session_open(Authctxt *authctxt, int chanid)
1388 Session *s = session_new();
1389 debug("session_open: channel %d", chanid);
1391 error("no more sessions");
1394 s->authctxt = authctxt;
1395 s->pw = authctxt->pw;
1397 fatal("no user for session %d", s->self);
1398 debug("session_open: session %d: link with channel %d", s->self, chanid);
1404 session_by_channel(int id)
1407 for (i = 0; i < MAX_SESSIONS; i++) {
1408 Session *s = &sessions[i];
1409 if (s->used && s->chanid == id) {
1410 debug("session_by_channel: session %d channel %d", i, id);
1414 debug("session_by_channel: unknown channel %d", id);
1420 session_by_pid(pid_t pid)
1423 debug("session_by_pid: pid %d", pid);
1424 for (i = 0; i < MAX_SESSIONS; i++) {
1425 Session *s = &sessions[i];
1426 if (s->used && s->pid == pid)
1429 error("session_by_pid: unknown pid %d", pid);
1435 session_window_change_req(Session *s)
1437 s->col = packet_get_int();
1438 s->row = packet_get_int();
1439 s->xpixel = packet_get_int();
1440 s->ypixel = packet_get_int();
1442 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1447 session_pty_req(Session *s)
1453 debug("Allocating a pty not permitted for this authentication.");
1456 if (s->ttyfd != -1) {
1457 packet_disconnect("Protocol error: you already have a pty.");
1461 s->term = packet_get_string(&len);
1464 s->col = packet_get_int();
1465 s->row = packet_get_int();
1467 s->row = packet_get_int();
1468 s->col = packet_get_int();
1470 s->xpixel = packet_get_int();
1471 s->ypixel = packet_get_int();
1473 if (strcmp(s->term, "") == 0) {
1478 /* Allocate a pty and open it. */
1479 debug("Allocating pty.");
1480 if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) {
1486 error("session_pty_req: session %d alloc failed", s->self);
1489 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1491 /* for SSH1 the tty modes length is not given */
1493 n_bytes = packet_remaining();
1494 tty_parse_modes(s->ttyfd, &n_bytes);
1497 * Add a cleanup function to clear the utmp entry and record logout
1498 * time in case we call fatal() (e.g., the connection gets closed).
1500 fatal_add_cleanup(session_pty_cleanup, (void *)s);
1501 pty_setowner(s->pw, s->tty);
1503 /* Set window size from the packet. */
1504 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1507 session_proctitle(s);
1512 session_subsystem_req(Session *s)
1517 char *cmd, *subsys = packet_get_string(&len);
1521 log("subsystem request for %.100s", subsys);
1523 for (i = 0; i < options.num_subsystems; i++) {
1524 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1525 cmd = options.subsystem_command[i];
1526 if (stat(cmd, &st) < 0) {
1527 error("subsystem: cannot stat %s: %s", cmd,
1531 debug("subsystem: exec() %s", cmd);
1532 s->is_subsystem = 1;
1540 log("subsystem request for %.100s failed, subsystem not found",
1548 session_x11_req(Session *s)
1552 s->single_connection = packet_get_char();
1553 s->auth_proto = packet_get_string(NULL);
1554 s->auth_data = packet_get_string(NULL);
1555 s->screen = packet_get_int();
1558 success = session_setup_x11fwd(s);
1560 xfree(s->auth_proto);
1561 xfree(s->auth_data);
1562 s->auth_proto = NULL;
1563 s->auth_data = NULL;
1569 session_shell_req(Session *s)
1577 session_exec_req(Session *s)
1580 char *command = packet_get_string(&len);
1582 do_exec(s, command);
1588 session_auth_agent_req(Session *s)
1590 static int called = 0;
1592 if (no_agent_forwarding_flag) {
1593 debug("session_auth_agent_req: no_agent_forwarding_flag");
1600 return auth_input_request_forwarding(s->pw);
1605 session_input_channel_req(Channel *c, const char *rtype)
1610 if ((s = session_by_channel(c->self)) == NULL) {
1611 log("session_input_channel_req: no session %d req %.100s",
1615 debug("session_input_channel_req: session %d req %s", s->self, rtype);
1618 * a session is in LARVAL state until a shell, a command
1619 * or a subsystem is executed
1621 if (c->type == SSH_CHANNEL_LARVAL) {
1622 if (strcmp(rtype, "shell") == 0) {
1623 success = session_shell_req(s);
1624 } else if (strcmp(rtype, "exec") == 0) {
1625 success = session_exec_req(s);
1626 } else if (strcmp(rtype, "pty-req") == 0) {
1627 success = session_pty_req(s);
1628 } else if (strcmp(rtype, "x11-req") == 0) {
1629 success = session_x11_req(s);
1630 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1631 success = session_auth_agent_req(s);
1632 } else if (strcmp(rtype, "subsystem") == 0) {
1633 success = session_subsystem_req(s);
1636 if (strcmp(rtype, "window-change") == 0) {
1637 success = session_window_change_req(s);
1643 session_set_fds(Session *s, int fdin, int fdout, int fderr)
1646 fatal("session_set_fds: called for proto != 2.0");
1648 * now that have a child and a pipe to the child,
1649 * we can activate our channel and register the fd's
1651 if (s->chanid == -1)
1652 fatal("no channel for session %d", s->self);
1653 channel_set_fds(s->chanid,
1655 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1657 CHAN_SES_WINDOW_DEFAULT);
1661 * Function to perform pty cleanup. Also called if we get aborted abnormally
1662 * (e.g., due to a dropped connection).
1665 session_pty_cleanup(void *session)
1667 Session *s = session;
1670 error("session_pty_cleanup: no session");
1676 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1678 /* Record that the user has logged out. */
1680 record_logout(s->pid, s->tty, s->pw->pw_name);
1682 /* Release the pseudo-tty. */
1683 pty_release(s->tty);
1686 * Close the server side of the socket pairs. We must do this after
1687 * the pty cleanup, so that another process doesn't get this pty
1688 * while we're still cleaning up.
1690 if (close(s->ptymaster) < 0)
1691 error("close(s->ptymaster): %s", strerror(errno));
1693 /* unlink pty from session */
1698 session_exit_message(Session *s, int status)
1702 if ((c = channel_lookup(s->chanid)) == NULL)
1703 fatal("session_exit_message: session %d: no channel %d",
1704 s->self, s->chanid);
1705 debug("session_exit_message: session %d channel %d pid %d",
1706 s->self, s->chanid, s->pid);
1708 if (WIFEXITED(status)) {
1709 channel_request_start(s->chanid, "exit-status", 0);
1710 packet_put_int(WEXITSTATUS(status));
1712 } else if (WIFSIGNALED(status)) {
1713 channel_request_start(s->chanid, "exit-signal", 0);
1714 packet_put_int(WTERMSIG(status));
1716 packet_put_char(WCOREDUMP(status));
1717 #else /* WCOREDUMP */
1719 #endif /* WCOREDUMP */
1720 packet_put_cstring("");
1721 packet_put_cstring("");
1724 /* Some weird exit cause. Just exit. */
1725 packet_disconnect("wait returned status %04x.", status);
1728 /* disconnect channel */
1729 debug("session_exit_message: release channel %d", s->chanid);
1730 channel_cancel_cleanup(s->chanid);
1732 * emulate a write failure with 'chan_write_failed', nobody will be
1733 * interested in data we write.
1734 * Note that we must not call 'chan_read_failed', since there could
1735 * be some more data waiting in the pipe.
1737 if (c->ostate != CHAN_OUTPUT_CLOSED)
1738 chan_write_failed(c);
1743 session_close(Session *s)
1745 debug("session_close: session %d pid %d", s->self, s->pid);
1746 if (s->ttyfd != -1) {
1747 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1748 session_pty_cleanup(s);
1754 if (s->auth_display)
1755 xfree(s->auth_display);
1757 xfree(s->auth_data);
1759 xfree(s->auth_proto);
1761 session_proctitle(s);
1765 session_close_by_pid(pid_t pid, int status)
1767 Session *s = session_by_pid(pid);
1769 debug("session_close_by_pid: no session for pid %d", pid);
1772 if (s->chanid != -1)
1773 session_exit_message(s, status);
1778 * this is called when a channel dies before
1779 * the session 'child' itself dies
1782 session_close_by_channel(int id, void *arg)
1784 Session *s = session_by_channel(id);
1786 debug("session_close_by_channel: no session for id %d", id);
1789 debug("session_close_by_channel: channel %d child %d", id, s->pid);
1791 debug("session_close_by_channel: channel %d: has child", id);
1793 * delay detach of session, but release pty, since
1794 * the fd's to the child are already closed
1796 if (s->ttyfd != -1) {
1797 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1798 session_pty_cleanup(s);
1802 /* detach by removing callback */
1803 channel_cancel_cleanup(s->chanid);
1809 session_destroy_all(void)
1812 for (i = 0; i < MAX_SESSIONS; i++) {
1813 Session *s = &sessions[i];
1820 session_tty_list(void)
1822 static char buf[1024];
1825 for (i = 0; i < MAX_SESSIONS; i++) {
1826 Session *s = &sessions[i];
1827 if (s->used && s->ttyfd != -1) {
1829 strlcat(buf, ",", sizeof buf);
1830 strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1834 strlcpy(buf, "notty", sizeof buf);
1839 session_proctitle(Session *s)
1842 error("no user for session %d", s->self);
1844 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1848 session_setup_x11fwd(Session *s)
1851 char display[512], auth_display[512];
1852 char hostname[MAXHOSTNAMELEN];
1854 if (no_x11_forwarding_flag) {
1855 packet_send_debug("X11 forwarding disabled in user configuration file.");
1858 if (!options.x11_forwarding) {
1859 debug("X11 forwarding disabled in server configuration file.");
1862 if (!options.xauth_location ||
1863 (stat(options.xauth_location, &st) == -1)) {
1864 packet_send_debug("No xauth program; cannot forward with spoofing.");
1867 if (options.use_login) {
1868 packet_send_debug("X11 forwarding disabled; "
1869 "not compatible with UseLogin=yes.");
1872 if (s->display != NULL) {
1873 debug("X11 display already set.");
1876 s->display_number = x11_create_display_inet(options.x11_display_offset,
1877 options.x11_use_localhost, s->single_connection);
1878 if (s->display_number == -1) {
1879 debug("x11_create_display_inet failed.");
1883 /* Set up a suitable value for the DISPLAY variable. */
1884 if (gethostname(hostname, sizeof(hostname)) < 0)
1885 fatal("gethostname: %.100s", strerror(errno));
1887 * auth_display must be used as the displayname when the
1888 * authorization entry is added with xauth(1). This will be
1889 * different than the DISPLAY string for localhost displays.
1891 if (options.x11_use_localhost) {
1892 snprintf(display, sizeof display, "localhost:%d.%d",
1893 s->display_number, s->screen);
1894 snprintf(auth_display, sizeof auth_display, "unix:%d.%d",
1895 s->display_number, s->screen);
1896 s->display = xstrdup(display);
1897 s->auth_display = xstrdup(auth_display);
1899 #ifdef IPADDR_IN_DISPLAY
1901 struct in_addr my_addr;
1903 he = gethostbyname(hostname);
1905 error("Can't get IP address for X11 DISPLAY.");
1906 packet_send_debug("Can't get IP address for X11 DISPLAY.");
1909 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
1910 snprintf(display, sizeof display, "%.50s:%d.%d", inet_ntoa(my_addr),
1911 s->display_number, s->screen);
1913 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
1914 s->display_number, s->screen);
1916 s->display = xstrdup(display);
1917 s->auth_display = xstrdup(display);
1924 do_authenticated2(Authctxt *authctxt)
1926 server_loop2(authctxt);