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 1.131 2002/03/19 10:35:39 markus Exp $");
51 #include "auth-options.h"
52 #include "pathnames.h"
56 #include "serverloop.h"
59 #include "monitor_wrap.h"
63 #include <sys/cygwin.h>
64 #define is_winnt (GetVersion() < 0x80000000)
69 Session *session_new(void);
70 void session_set_fds(Session *, int, int, int);
71 void session_pty_cleanup(void *);
72 void session_proctitle(Session *);
73 int session_setup_x11fwd(Session *);
74 void do_exec_pty(Session *, const char *);
75 void do_exec_no_pty(Session *, const char *);
76 void do_exec(Session *, const char *);
77 void do_login(Session *, const char *);
78 #ifdef LOGIN_NEEDS_UTMPX
79 static void do_pre_login(Session *s);
81 void do_child(Session *, const char *);
83 int check_quietlogin(Session *, const char *);
85 static void do_authenticated1(Authctxt *);
86 static void do_authenticated2(Authctxt *);
88 static int session_pty_req(Session *);
91 extern ServerOptions options;
92 extern char *__progname;
93 extern int log_stderr;
94 extern int debug_flag;
95 extern u_int utmp_len;
96 extern int startup_pipe;
97 extern void destroy_sensitive_data(void);
99 /* original command from peer. */
100 const char *original_command = NULL;
103 #define MAX_SESSIONS 10
104 Session sessions[MAX_SESSIONS];
106 #ifdef WITH_AIXAUTHENTICATE
108 #endif /* WITH_AIXAUTHENTICATE */
110 #ifdef HAVE_LOGIN_CAP
115 do_authenticated(Authctxt *authctxt)
118 * Cancel the alarm we set to limit the time taken for
122 if (startup_pipe != -1) {
126 #ifdef WITH_AIXAUTHENTICATE
127 /* We don't have a pty yet, so just label the line as "ssh" */
128 if (loginsuccess(authctxt->user,
129 get_canonical_hostname(options.verify_reverse_mapping),
130 "ssh", &aixloginmsg) < 0)
132 #endif /* WITH_AIXAUTHENTICATE */
134 /* setup the channel layer */
135 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
136 channel_permit_all_opens();
139 do_authenticated2(authctxt);
141 do_authenticated1(authctxt);
143 /* remove agent socket */
144 if (auth_get_socket_name())
145 auth_sock_cleanup_proc(authctxt->pw);
147 if (options.kerberos_ticket_cleanup)
148 krb4_cleanup_proc(authctxt);
151 if (options.kerberos_ticket_cleanup)
152 krb5_cleanup_proc(authctxt);
157 * Prepares for an interactive session. This is called after the user has
158 * been successfully authenticated. During this message exchange, pseudo
159 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
160 * are requested, etc.
163 do_authenticated1(Authctxt *authctxt)
167 int success, type, screen_flag;
168 int compression_level = 0, enable_compression_after_reply = 0;
169 u_int proto_len, data_len, dlen;
172 s->authctxt = authctxt;
173 s->pw = authctxt->pw;
176 * We stay in this loop until the client requests to execute a shell
182 /* Get a packet from the client. */
183 type = packet_read();
185 /* Process the packet. */
187 case SSH_CMSG_REQUEST_COMPRESSION:
188 compression_level = packet_get_int();
190 if (compression_level < 1 || compression_level > 9) {
191 packet_send_debug("Received illegal compression level %d.",
195 /* Enable compression after we have responded with SUCCESS. */
196 enable_compression_after_reply = 1;
200 case SSH_CMSG_REQUEST_PTY:
201 success = session_pty_req(s);
204 case SSH_CMSG_X11_REQUEST_FORWARDING:
205 s->auth_proto = packet_get_string(&proto_len);
206 s->auth_data = packet_get_string(&data_len);
208 screen_flag = packet_get_protocol_flags() &
209 SSH_PROTOFLAG_SCREEN_NUMBER;
210 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
212 if (packet_remaining() == 4) {
214 debug2("Buggy client: "
215 "X11 screen flag missing");
216 s->screen = packet_get_int();
221 success = session_setup_x11fwd(s);
223 xfree(s->auth_proto);
225 s->auth_proto = NULL;
230 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
231 if (no_agent_forwarding_flag || compat13) {
232 debug("Authentication agent forwarding not permitted for this authentication.");
235 debug("Received authentication agent forwarding request.");
236 success = auth_input_request_forwarding(s->pw);
239 case SSH_CMSG_PORT_FORWARD_REQUEST:
240 if (no_port_forwarding_flag) {
241 debug("Port forwarding not permitted for this authentication.");
244 if (!options.allow_tcp_forwarding) {
245 debug("Port forwarding not permitted.");
248 debug("Received TCP/IP port forwarding request.");
249 channel_input_port_forward_request(s->pw->pw_uid == 0, options.gateway_ports);
253 case SSH_CMSG_MAX_PACKET_SIZE:
254 if (packet_set_maxsize(packet_get_int()) > 0)
258 #if defined(AFS) || defined(KRB5)
259 case SSH_CMSG_HAVE_KERBEROS_TGT:
260 if (!options.kerberos_tgt_passing) {
261 verbose("Kerberos TGT passing disabled.");
263 char *kdata = packet_get_string(&dlen);
266 /* XXX - 0x41, see creds_to_radix version */
267 if (kdata[0] != 0x41) {
273 if (auth_krb5_tgt(s->authctxt, &tgt))
276 verbose("Kerberos v5 TGT refused for %.100s", s->authctxt->user);
280 if (auth_krb4_tgt(s->authctxt, kdata))
283 verbose("Kerberos v4 TGT refused for %.100s", s->authctxt->user);
289 #endif /* AFS || KRB5 */
292 case SSH_CMSG_HAVE_AFS_TOKEN:
293 if (!options.afs_token_passing || !k_hasafs()) {
294 verbose("AFS token passing disabled.");
296 /* Accept AFS token. */
297 char *token = packet_get_string(&dlen);
300 if (auth_afs_token(s->authctxt, token))
303 verbose("AFS token refused for %.100s",
310 case SSH_CMSG_EXEC_SHELL:
311 case SSH_CMSG_EXEC_CMD:
312 if (type == SSH_CMSG_EXEC_CMD) {
313 command = packet_get_string(&dlen);
314 debug("Exec command '%.500s'", command);
326 * Any unknown messages in this phase are ignored,
327 * and a failure message is returned.
329 log("Unknown packet type received after authentication: %d", type);
331 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
335 /* Enable compression now that we have replied if appropriate. */
336 if (enable_compression_after_reply) {
337 enable_compression_after_reply = 0;
338 packet_start_compression(compression_level);
344 * This is called to fork and execute a command when we have no tty. This
345 * will call do_child from the child, and server_loop from the parent after
346 * setting up file descriptors and such.
349 do_exec_no_pty(Session *s, const char *command)
354 int pin[2], pout[2], perr[2];
355 /* Allocate pipes for communicating with the program. */
356 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
357 packet_disconnect("Could not create pipes: %.100s",
359 #else /* USE_PIPES */
360 int inout[2], err[2];
361 /* Uses socket pairs to communicate with the program. */
362 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
363 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
364 packet_disconnect("Could not create socket pairs: %.100s",
366 #endif /* USE_PIPES */
368 fatal("do_exec_no_pty: no session");
370 session_proctitle(s);
373 do_pam_session(s->pw->pw_name, NULL);
375 if (is_pam_password_change_required())
376 packet_disconnect("Password change required but no "
380 /* Fork the child. */
381 if ((pid = fork()) == 0) {
382 /* Child. Reinitialize the log since the pid has changed. */
383 log_init(__progname, options.log_level, options.log_facility, log_stderr);
386 * Create a new session and process group since the 4.4BSD
387 * setlogin() affects the entire process group.
390 error("setsid failed: %.100s", strerror(errno));
394 * Redirect stdin. We close the parent side of the socket
395 * pair, and make the child side the standard input.
398 if (dup2(pin[0], 0) < 0)
399 perror("dup2 stdin");
402 /* Redirect stdout. */
404 if (dup2(pout[1], 1) < 0)
405 perror("dup2 stdout");
408 /* Redirect stderr. */
410 if (dup2(perr[1], 2) < 0)
411 perror("dup2 stderr");
413 #else /* USE_PIPES */
415 * Redirect stdin, stdout, and stderr. Stdin and stdout will
416 * use the same socket, as some programs (particularly rdist)
417 * seem to depend on it.
421 if (dup2(inout[0], 0) < 0) /* stdin */
422 perror("dup2 stdin");
423 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
424 perror("dup2 stdout");
425 if (dup2(err[0], 2) < 0) /* stderr */
426 perror("dup2 stderr");
427 #endif /* USE_PIPES */
429 /* Do processing for the child (exec command etc). */
430 do_child(s, command);
435 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
438 packet_disconnect("fork failed: %.100s", strerror(errno));
440 /* Set interactive/non-interactive mode. */
441 packet_set_interactive(s->display != NULL);
443 /* We are the parent. Close the child sides of the pipes. */
449 session_set_fds(s, pin[1], pout[0], s->is_subsystem ? -1 : perr[0]);
451 /* Enter the interactive session. */
452 server_loop(pid, pin[1], pout[0], perr[0]);
453 /* server_loop has closed pin[1], pout[0], and perr[0]. */
455 #else /* USE_PIPES */
456 /* We are the parent. Close the child sides of the socket pairs. */
461 * Enter the interactive session. Note: server_loop must be able to
462 * handle the case that fdin and fdout are the same.
465 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
467 server_loop(pid, inout[1], inout[1], err[1]);
468 /* server_loop has closed inout[1] and err[1]. */
470 #endif /* USE_PIPES */
474 * This is called to fork and execute a command when we have a tty. This
475 * will call do_child from the child, and server_loop from the parent after
476 * setting up file descriptors, controlling tty, updating wtmp, utmp,
477 * lastlog, and other such operations.
480 do_exec_pty(Session *s, const char *command)
482 int fdout, ptyfd, ttyfd, ptymaster;
486 fatal("do_exec_pty: no session");
491 do_pam_session(s->pw->pw_name, s->tty);
495 /* Fork the child. */
496 if ((pid = fork()) == 0) {
498 /* Child. Reinitialize the log because the pid has changed. */
499 log_init(__progname, options.log_level, options.log_facility, log_stderr);
500 /* Close the master side of the pseudo tty. */
503 /* Make the pseudo tty our controlling tty. */
504 pty_make_controlling_tty(&ttyfd, s->tty);
506 /* Redirect stdin/stdout/stderr from the pseudo tty. */
507 if (dup2(ttyfd, 0) < 0)
508 error("dup2 stdin: %s", strerror(errno));
509 if (dup2(ttyfd, 1) < 0)
510 error("dup2 stdout: %s", strerror(errno));
511 if (dup2(ttyfd, 2) < 0)
512 error("dup2 stderr: %s", strerror(errno));
514 /* Close the extra descriptor for the pseudo tty. */
517 /* record login, etc. similar to login(1) */
519 if (!(options.use_login && command == NULL))
520 do_login(s, command);
521 # ifdef LOGIN_NEEDS_UTMPX
527 /* Do common processing for the child, such as execing the command. */
528 do_child(s, command);
533 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
536 packet_disconnect("fork failed: %.100s", strerror(errno));
539 /* Parent. Close the slave side of the pseudo tty. */
543 * Create another descriptor of the pty master side for use as the
544 * standard input. We could use the original descriptor, but this
545 * simplifies code in server_loop. The descriptor is bidirectional.
549 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
551 /* we keep a reference to the pty master */
552 ptymaster = dup(ptyfd);
554 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
555 s->ptymaster = ptymaster;
557 /* Enter interactive session. */
558 packet_set_interactive(1);
560 session_set_fds(s, ptyfd, fdout, -1);
562 server_loop(pid, ptyfd, fdout, -1);
563 /* server_loop _has_ closed ptyfd and fdout. */
567 #ifdef LOGIN_NEEDS_UTMPX
569 do_pre_login(Session *s)
572 struct sockaddr_storage from;
573 pid_t pid = getpid();
576 * Get IP address of client. If the connection is not a socket, let
577 * the address be 0.0.0.0.
579 memset(&from, 0, sizeof(from));
580 if (packet_connection_is_on_socket()) {
581 fromlen = sizeof(from);
582 if (getpeername(packet_get_connection_in(),
583 (struct sockaddr *) & from, &fromlen) < 0) {
584 debug("getpeername: %.100s", strerror(errno));
589 record_utmp_only(pid, s->tty, s->pw->pw_name,
590 get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping),
591 (struct sockaddr *)&from);
596 * This is called to fork and execute a command. If another command is
597 * to be forced, execute that instead.
600 do_exec(Session *s, const char *command)
602 if (forced_command) {
603 original_command = command;
604 command = forced_command;
605 debug("Forced command '%.900s'", command);
609 do_exec_pty(s, command);
611 do_exec_no_pty(s, command);
613 original_command = NULL;
617 /* administrative, login(1)-like work */
619 do_login(Session *s, const char *command)
622 char hostname[MAXHOSTNAMELEN];
624 struct sockaddr_storage from;
625 time_t last_login_time;
626 struct passwd * pw = s->pw;
627 pid_t pid = getpid();
630 * Get IP address of client. If the connection is not a socket, let
631 * the address be 0.0.0.0.
633 memset(&from, 0, sizeof(from));
634 if (packet_connection_is_on_socket()) {
635 fromlen = sizeof(from);
636 if (getpeername(packet_get_connection_in(),
637 (struct sockaddr *) & from, &fromlen) < 0) {
638 debug("getpeername: %.100s", strerror(errno));
643 /* Get the time and hostname when the user last logged in. */
644 if (options.print_lastlog) {
646 last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
647 hostname, sizeof(hostname));
650 /* Record that there was a login on that tty from the remote host. */
651 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
652 get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping),
653 (struct sockaddr *)&from);
657 * If password change is needed, do it now.
658 * This needs to occur before the ~/.hushlogin check.
660 if (is_pam_password_change_required()) {
661 print_pam_messages();
666 if (check_quietlogin(s, command))
670 if (!is_pam_password_change_required())
671 print_pam_messages();
673 #ifdef WITH_AIXAUTHENTICATE
674 if (aixloginmsg && *aixloginmsg)
675 printf("%s\n", aixloginmsg);
676 #endif /* WITH_AIXAUTHENTICATE */
678 if (options.print_lastlog && last_login_time != 0) {
679 time_string = ctime(&last_login_time);
680 if (strchr(time_string, '\n'))
681 *strchr(time_string, '\n') = 0;
682 if (strcmp(hostname, "") == 0)
683 printf("Last login: %s\r\n", time_string);
685 printf("Last login: %s from %s\r\n", time_string, hostname);
692 * Display the message of the day.
700 if (options.print_motd) {
701 #ifdef HAVE_LOGIN_CAP
702 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
705 f = fopen("/etc/motd", "r");
708 while (fgets(buf, sizeof(buf), f))
717 * Check for quiet login, either .hushlogin or command given.
720 check_quietlogin(Session *s, const char *command)
723 struct passwd *pw = s->pw;
726 /* Return 1 if .hushlogin exists or a command given. */
729 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
730 #ifdef HAVE_LOGIN_CAP
731 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
734 if (stat(buf, &st) >= 0)
741 * Sets the value of the given variable in the environment. If the variable
742 * already exists, its value is overriden.
745 child_set_env(char ***envp, u_int *envsizep, const char *name,
752 * Find the slot where the value should be stored. If the variable
753 * already exists, we reuse the slot; otherwise we append a new slot
754 * at the end of the array, expanding if necessary.
757 namelen = strlen(name);
758 for (i = 0; env[i]; i++)
759 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
762 /* Reuse the slot. */
765 /* New variable. Expand if necessary. */
766 if (i >= (*envsizep) - 1) {
768 env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
770 /* Need to set the NULL pointer at end of array beyond the new slot. */
774 /* Allocate space and format the variable in the appropriate slot. */
775 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
776 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
780 * Reads environment variables from the given file and adds/overrides them
781 * into the environment. If the file does not exist, this does nothing.
782 * Otherwise, it must consist of empty lines, comments (line starts with '#')
783 * and assignments of the form name=value. No other forms are allowed.
786 read_environment_file(char ***env, u_int *envsize,
787 const char *filename)
793 f = fopen(filename, "r");
797 while (fgets(buf, sizeof(buf), f)) {
798 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
800 if (!*cp || *cp == '#' || *cp == '\n')
802 if (strchr(cp, '\n'))
803 *strchr(cp, '\n') = '\0';
804 value = strchr(cp, '=');
806 fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
810 * Replace the equals sign by nul, and advance value to
815 child_set_env(env, envsize, cp, value);
820 void copy_environment(char **source, char ***env, u_int *envsize)
822 char *var_name, *var_val;
828 for(i = 0; source[i] != NULL; i++) {
829 var_name = xstrdup(source[i]);
830 if ((var_val = strstr(var_name, "=")) == NULL) {
836 debug3("Copy environment: %s=%s", var_name, var_val);
837 child_set_env(env, envsize, var_name, var_val);
844 do_setup_env(Session *s, const char *shell)
849 struct passwd *pw = s->pw;
851 /* Initialize the environment. */
853 env = xmalloc(envsize * sizeof(char *));
858 * The Windows environment contains some setting which are
859 * important for a running system. They must not be dropped.
861 copy_environment(environ, &env, &envsize);
864 if (!options.use_login) {
865 /* Set basic environment. */
866 child_set_env(&env, &envsize, "USER", pw->pw_name);
867 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
868 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
869 #ifdef HAVE_LOGIN_CAP
870 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH);
871 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
872 #else /* HAVE_LOGIN_CAP */
875 * There's no standard path on Windows. The path contains
876 * important components pointing to the system directories,
877 * needed for loading shared libraries. So the path better
878 * remains intact here.
880 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
881 # endif /* HAVE_CYGWIN */
882 #endif /* HAVE_LOGIN_CAP */
884 snprintf(buf, sizeof buf, "%.200s/%.50s",
885 _PATH_MAILDIR, pw->pw_name);
886 child_set_env(&env, &envsize, "MAIL", buf);
888 /* Normal systems set SHELL by default. */
889 child_set_env(&env, &envsize, "SHELL", shell);
892 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
894 /* Set custom environment options from RSA authentication. */
895 if (!options.use_login) {
896 while (custom_environment) {
897 struct envstring *ce = custom_environment;
900 for (i = 0; s[i] != '=' && s[i]; i++)
904 child_set_env(&env, &envsize, s, s + i + 1);
906 custom_environment = ce->next;
912 snprintf(buf, sizeof buf, "%.50s %d %d",
913 get_remote_ipaddr(), get_remote_port(), get_local_port());
914 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
917 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
919 child_set_env(&env, &envsize, "TERM", s->term);
921 child_set_env(&env, &envsize, "DISPLAY", s->display);
922 if (original_command)
923 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
930 if ((cp = getenv("AUTHSTATE")) != NULL)
931 child_set_env(&env, &envsize, "AUTHSTATE", cp);
932 if ((cp = getenv("KRB5CCNAME")) != NULL)
933 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
934 read_environment_file(&env, &envsize, "/etc/environment");
938 if (s->authctxt->krb4_ticket_file)
939 child_set_env(&env, &envsize, "KRBTKFILE",
940 s->authctxt->krb4_ticket_file);
943 if (s->authctxt->krb5_ticket_file)
944 child_set_env(&env, &envsize, "KRB5CCNAME",
945 s->authctxt->krb5_ticket_file);
948 /* Pull in any environment variables that may have been set by PAM. */
949 copy_environment(fetch_pam_environment(), &env, &envsize);
952 if (auth_get_socket_name() != NULL)
953 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
954 auth_get_socket_name());
956 /* read $HOME/.ssh/environment. */
957 if (!options.use_login) {
958 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
960 read_environment_file(&env, &envsize, buf);
963 /* dump the environment */
964 fprintf(stderr, "Environment:\n");
965 for (i = 0; env[i]; i++)
966 fprintf(stderr, " %.200s\n", env[i]);
972 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
973 * first in this order).
976 do_rc_files(Session *s, const char *shell)
984 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
986 /* ignore _PATH_SSH_USER_RC for subsystems */
987 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
988 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
989 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
991 fprintf(stderr, "Running %s\n", cmd);
995 fprintf(f, "%s %s\n", s->auth_proto,
999 fprintf(stderr, "Could not run %s\n",
1001 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1003 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1004 _PATH_SSH_SYSTEM_RC);
1005 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1008 fprintf(f, "%s %s\n", s->auth_proto,
1012 fprintf(stderr, "Could not run %s\n",
1013 _PATH_SSH_SYSTEM_RC);
1014 } else if (do_xauth && options.xauth_location != NULL) {
1015 /* Add authority data to .Xauthority if appropriate. */
1018 "Running %.100s add "
1019 "%.100s %.100s %.100s\n",
1020 options.xauth_location, s->auth_display,
1021 s->auth_proto, s->auth_data);
1023 snprintf(cmd, sizeof cmd, "%s -q -",
1024 options.xauth_location);
1025 f = popen(cmd, "w");
1027 fprintf(f, "add %s %s %s\n",
1028 s->auth_display, s->auth_proto,
1032 fprintf(stderr, "Could not run %s\n",
1039 do_nologin(struct passwd *pw)
1044 #ifdef HAVE_LOGIN_CAP
1045 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1046 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1047 _PATH_NOLOGIN), "r");
1050 f = fopen(_PATH_NOLOGIN, "r");
1053 /* /etc/nologin exists. Print its contents and exit. */
1054 while (fgets(buf, sizeof(buf), f))
1061 /* Set login name, uid, gid, and groups. */
1063 do_setusercontext(struct passwd *pw)
1067 #else /* HAVE_CYGWIN */
1068 if (getuid() == 0 || geteuid() == 0) {
1069 #endif /* HAVE_CYGWIN */
1070 #ifdef HAVE_GETUSERATTR
1071 set_limits_from_userattr(pw->pw_name);
1072 #endif /* HAVE_GETUSERATTR */
1073 #ifdef HAVE_LOGIN_CAP
1074 if (setusercontext(lc, pw, pw->pw_uid,
1075 (LOGIN_SETALL & ~LOGIN_SETPATH)) < 0) {
1076 perror("unable to set user context");
1080 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1081 /* Sets login uid for accounting */
1082 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1083 error("setluid: %s", strerror(errno));
1084 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1086 if (setlogin(pw->pw_name) < 0)
1087 error("setlogin failed: %s", strerror(errno));
1088 if (setgid(pw->pw_gid) < 0) {
1092 /* Initialize the group list. */
1093 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1094 perror("initgroups");
1100 * PAM credentials may take the form of supplementary groups.
1101 * These will have been wiped by the above initgroups() call.
1102 * Reestablish them here.
1105 # endif /* USE_PAM */
1106 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1107 irix_setusercontext(pw);
1108 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1109 /* Permanently switch to the desired uid. */
1110 permanently_set_uid(pw);
1113 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1114 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1118 launch_login(struct passwd *pw, const char *hostname)
1120 /* Launch login(1). */
1122 execl("/usr/bin/login", "login", "-h", hostname,
1123 #ifdef LOGIN_NEEDS_TERM
1124 (s->term ? s->term : "unknown"),
1125 #endif /* LOGIN_NEEDS_TERM */
1126 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1128 /* Login couldn't be executed, die. */
1135 * Performs common processing for the child, such as setting up the
1136 * environment, closing extra file descriptors, setting the user and group
1137 * ids, and executing the command or shell.
1140 do_child(Session *s, const char *command)
1142 extern char **environ;
1145 const char *shell, *shell0, *hostname = NULL;
1146 struct passwd *pw = s->pw;
1149 /* remove hostkey from the child's memory */
1150 destroy_sensitive_data();
1152 /* login(1) is only called if we execute the login shell */
1153 if (options.use_login && command != NULL)
1154 options.use_login = 0;
1157 * Login(1) does this as well, and it needs uid 0 for the "-h"
1158 * switch, so we let login(1) to this for us.
1160 if (!options.use_login) {
1162 session_setup_sia(pw->pw_name, s->ttyfd == -1 ? NULL : s->tty);
1163 if (!check_quietlogin(s, command))
1165 #else /* HAVE_OSF_SIA */
1168 aix_usrinfo(pw, s->tty, s->ttyfd);
1170 do_setusercontext(pw);
1171 #endif /* HAVE_OSF_SIA */
1175 * Get the shell from the password data. An empty shell field is
1176 * legal, and means /bin/sh.
1178 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1179 #ifdef HAVE_LOGIN_CAP
1180 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1183 env = do_setup_env(s, shell);
1185 /* we have to stash the hostname before we close our socket. */
1186 if (options.use_login)
1187 hostname = get_remote_name_or_ip(utmp_len,
1188 options.verify_reverse_mapping);
1190 * Close the connection descriptors; note that this is the child, and
1191 * the server will still have the socket open, and it is important
1192 * that we do not shutdown it. Note that the descriptors cannot be
1193 * closed before building the environment, as we call
1194 * get_remote_ipaddr there.
1196 if (packet_get_connection_in() == packet_get_connection_out())
1197 close(packet_get_connection_in());
1199 close(packet_get_connection_in());
1200 close(packet_get_connection_out());
1203 * Close all descriptors related to channels. They will still remain
1204 * open in the parent.
1206 /* XXX better use close-on-exec? -markus */
1207 channel_close_all();
1210 * Close any extra file descriptors. Note that there may still be
1211 * descriptors left by system functions. They will be closed later.
1216 * Close any extra open file descriptors so that we don\'t have them
1217 * hanging around in clients. Note that we want to do this after
1218 * initgroups, because at least on Solaris 2.3 it leaves file
1221 for (i = 3; i < 64; i++)
1225 * Must take new environment into use so that .ssh/rc,
1226 * /etc/ssh/sshrc and xauth are run in the proper environment.
1231 /* Try to get AFS tokens for the local cell. */
1235 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1236 krb_afslog(cell, 0);
1242 /* Change current directory to the user\'s home directory. */
1243 if (chdir(pw->pw_dir) < 0) {
1244 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1245 pw->pw_dir, strerror(errno));
1246 #ifdef HAVE_LOGIN_CAP
1247 if (login_getcapbool(lc, "requirehome", 0))
1252 if (!options.use_login)
1253 do_rc_files(s, shell);
1255 /* restore SIGPIPE for child */
1256 signal(SIGPIPE, SIG_DFL);
1258 if (options.use_login) {
1259 launch_login(pw, hostname);
1263 /* Get the last component of the shell name. */
1264 if ((shell0 = strrchr(shell, '/')) != NULL)
1270 * If we have no command, execute the shell. In this case, the shell
1271 * name to be passed in argv[0] is preceded by '-' to indicate that
1272 * this is a login shell.
1277 /* Start the shell. Set initial character to '-'. */
1280 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1281 >= sizeof(argv0) - 1) {
1287 /* Execute the shell. */
1290 execve(shell, argv, env);
1292 /* Executing the shell failed. */
1297 * Execute the command using the user's shell. This uses the -c
1298 * option to execute the command.
1300 argv[0] = (char *) shell0;
1302 argv[2] = (char *) command;
1304 execve(shell, argv, env);
1313 static int did_init = 0;
1315 debug("session_new: init");
1316 for (i = 0; i < MAX_SESSIONS; i++) {
1317 sessions[i].used = 0;
1321 for (i = 0; i < MAX_SESSIONS; i++) {
1322 Session *s = &sessions[i];
1324 memset(s, 0, sizeof(*s));
1330 debug("session_new: session %d", i);
1341 for (i = 0; i < MAX_SESSIONS; i++) {
1342 Session *s = &sessions[i];
1343 debug("dump: used %d session %d %p channel %d pid %d",
1353 session_open(Authctxt *authctxt, int chanid)
1355 Session *s = session_new();
1356 debug("session_open: channel %d", chanid);
1358 error("no more sessions");
1361 s->authctxt = authctxt;
1362 s->pw = authctxt->pw;
1364 fatal("no user for session %d", s->self);
1365 debug("session_open: session %d: link with channel %d", s->self, chanid);
1371 session_by_tty(char *tty)
1374 for (i = 0; i < MAX_SESSIONS; i++) {
1375 Session *s = &sessions[i];
1376 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1377 debug("session_by_tty: session %d tty %s", i, tty);
1381 debug("session_by_tty: unknown tty %.100s", tty);
1387 session_by_channel(int id)
1390 for (i = 0; i < MAX_SESSIONS; i++) {
1391 Session *s = &sessions[i];
1392 if (s->used && s->chanid == id) {
1393 debug("session_by_channel: session %d channel %d", i, id);
1397 debug("session_by_channel: unknown channel %d", id);
1403 session_by_pid(pid_t pid)
1406 debug("session_by_pid: pid %d", pid);
1407 for (i = 0; i < MAX_SESSIONS; i++) {
1408 Session *s = &sessions[i];
1409 if (s->used && s->pid == pid)
1412 error("session_by_pid: unknown pid %d", pid);
1418 session_window_change_req(Session *s)
1420 s->col = packet_get_int();
1421 s->row = packet_get_int();
1422 s->xpixel = packet_get_int();
1423 s->ypixel = packet_get_int();
1425 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1430 session_pty_req(Session *s)
1436 debug("Allocating a pty not permitted for this authentication.");
1439 if (s->ttyfd != -1) {
1440 packet_disconnect("Protocol error: you already have a pty.");
1444 s->term = packet_get_string(&len);
1447 s->col = packet_get_int();
1448 s->row = packet_get_int();
1450 s->row = packet_get_int();
1451 s->col = packet_get_int();
1453 s->xpixel = packet_get_int();
1454 s->ypixel = packet_get_int();
1456 if (strcmp(s->term, "") == 0) {
1461 /* Allocate a pty and open it. */
1462 debug("Allocating pty.");
1463 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1469 error("session_pty_req: session %d alloc failed", s->self);
1472 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1474 /* for SSH1 the tty modes length is not given */
1476 n_bytes = packet_remaining();
1477 tty_parse_modes(s->ttyfd, &n_bytes);
1480 * Add a cleanup function to clear the utmp entry and record logout
1481 * time in case we call fatal() (e.g., the connection gets closed).
1483 fatal_add_cleanup(session_pty_cleanup, (void *)s);
1485 pty_setowner(s->pw, s->tty);
1487 /* Set window size from the packet. */
1488 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1491 session_proctitle(s);
1496 session_subsystem_req(Session *s)
1501 char *cmd, *subsys = packet_get_string(&len);
1505 log("subsystem request for %.100s", subsys);
1507 for (i = 0; i < options.num_subsystems; i++) {
1508 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1509 cmd = options.subsystem_command[i];
1510 if (stat(cmd, &st) < 0) {
1511 error("subsystem: cannot stat %s: %s", cmd,
1515 debug("subsystem: exec() %s", cmd);
1516 s->is_subsystem = 1;
1524 log("subsystem request for %.100s failed, subsystem not found",
1532 session_x11_req(Session *s)
1536 s->single_connection = packet_get_char();
1537 s->auth_proto = packet_get_string(NULL);
1538 s->auth_data = packet_get_string(NULL);
1539 s->screen = packet_get_int();
1542 success = session_setup_x11fwd(s);
1544 xfree(s->auth_proto);
1545 xfree(s->auth_data);
1546 s->auth_proto = NULL;
1547 s->auth_data = NULL;
1553 session_shell_req(Session *s)
1561 session_exec_req(Session *s)
1564 char *command = packet_get_string(&len);
1566 do_exec(s, command);
1572 session_auth_agent_req(Session *s)
1574 static int called = 0;
1576 if (no_agent_forwarding_flag) {
1577 debug("session_auth_agent_req: no_agent_forwarding_flag");
1584 return auth_input_request_forwarding(s->pw);
1589 session_input_channel_req(Channel *c, const char *rtype)
1594 if ((s = session_by_channel(c->self)) == NULL) {
1595 log("session_input_channel_req: no session %d req %.100s",
1599 debug("session_input_channel_req: session %d req %s", s->self, rtype);
1602 * a session is in LARVAL state until a shell, a command
1603 * or a subsystem is executed
1605 if (c->type == SSH_CHANNEL_LARVAL) {
1606 if (strcmp(rtype, "shell") == 0) {
1607 success = session_shell_req(s);
1608 } else if (strcmp(rtype, "exec") == 0) {
1609 success = session_exec_req(s);
1610 } else if (strcmp(rtype, "pty-req") == 0) {
1611 success = session_pty_req(s);
1612 } else if (strcmp(rtype, "x11-req") == 0) {
1613 success = session_x11_req(s);
1614 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
1615 success = session_auth_agent_req(s);
1616 } else if (strcmp(rtype, "subsystem") == 0) {
1617 success = session_subsystem_req(s);
1620 if (strcmp(rtype, "window-change") == 0) {
1621 success = session_window_change_req(s);
1627 session_set_fds(Session *s, int fdin, int fdout, int fderr)
1630 fatal("session_set_fds: called for proto != 2.0");
1632 * now that have a child and a pipe to the child,
1633 * we can activate our channel and register the fd's
1635 if (s->chanid == -1)
1636 fatal("no channel for session %d", s->self);
1637 channel_set_fds(s->chanid,
1639 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
1641 CHAN_SES_WINDOW_DEFAULT);
1645 * Function to perform pty cleanup. Also called if we get aborted abnormally
1646 * (e.g., due to a dropped connection).
1649 session_pty_cleanup2(void *session)
1651 Session *s = session;
1654 error("session_pty_cleanup: no session");
1660 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
1662 /* Record that the user has logged out. */
1664 record_logout(s->pid, s->tty, s->pw->pw_name);
1666 /* Release the pseudo-tty. */
1668 pty_release(s->tty);
1671 * Close the server side of the socket pairs. We must do this after
1672 * the pty cleanup, so that another process doesn't get this pty
1673 * while we're still cleaning up.
1675 if (close(s->ptymaster) < 0)
1676 error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
1678 /* unlink pty from session */
1683 session_pty_cleanup(void *session)
1685 PRIVSEP(session_pty_cleanup2(session));
1689 session_exit_message(Session *s, int status)
1693 if ((c = channel_lookup(s->chanid)) == NULL)
1694 fatal("session_exit_message: session %d: no channel %d",
1695 s->self, s->chanid);
1696 debug("session_exit_message: session %d channel %d pid %d",
1697 s->self, s->chanid, s->pid);
1699 if (WIFEXITED(status)) {
1700 channel_request_start(s->chanid, "exit-status", 0);
1701 packet_put_int(WEXITSTATUS(status));
1703 } else if (WIFSIGNALED(status)) {
1704 channel_request_start(s->chanid, "exit-signal", 0);
1705 packet_put_int(WTERMSIG(status));
1707 packet_put_char(WCOREDUMP(status));
1708 #else /* WCOREDUMP */
1710 #endif /* WCOREDUMP */
1711 packet_put_cstring("");
1712 packet_put_cstring("");
1715 /* Some weird exit cause. Just exit. */
1716 packet_disconnect("wait returned status %04x.", status);
1719 /* disconnect channel */
1720 debug("session_exit_message: release channel %d", s->chanid);
1721 channel_cancel_cleanup(s->chanid);
1723 * emulate a write failure with 'chan_write_failed', nobody will be
1724 * interested in data we write.
1725 * Note that we must not call 'chan_read_failed', since there could
1726 * be some more data waiting in the pipe.
1728 if (c->ostate != CHAN_OUTPUT_CLOSED)
1729 chan_write_failed(c);
1734 session_close(Session *s)
1736 debug("session_close: session %d pid %d", s->self, s->pid);
1737 if (s->ttyfd != -1) {
1738 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1739 session_pty_cleanup(s);
1745 if (s->auth_display)
1746 xfree(s->auth_display);
1748 xfree(s->auth_data);
1750 xfree(s->auth_proto);
1752 session_proctitle(s);
1756 session_close_by_pid(pid_t pid, int status)
1758 Session *s = session_by_pid(pid);
1760 debug("session_close_by_pid: no session for pid %d", pid);
1763 if (s->chanid != -1)
1764 session_exit_message(s, status);
1769 * this is called when a channel dies before
1770 * the session 'child' itself dies
1773 session_close_by_channel(int id, void *arg)
1775 Session *s = session_by_channel(id);
1777 debug("session_close_by_channel: no session for id %d", id);
1780 debug("session_close_by_channel: channel %d child %d", id, s->pid);
1782 debug("session_close_by_channel: channel %d: has child", id);
1784 * delay detach of session, but release pty, since
1785 * the fd's to the child are already closed
1787 if (s->ttyfd != -1) {
1788 fatal_remove_cleanup(session_pty_cleanup, (void *)s);
1789 session_pty_cleanup(s);
1793 /* detach by removing callback */
1794 channel_cancel_cleanup(s->chanid);
1800 session_destroy_all(void (*closefunc)(Session *))
1803 for (i = 0; i < MAX_SESSIONS; i++) {
1804 Session *s = &sessions[i];
1806 if (closefunc != NULL)
1815 session_tty_list(void)
1817 static char buf[1024];
1820 for (i = 0; i < MAX_SESSIONS; i++) {
1821 Session *s = &sessions[i];
1822 if (s->used && s->ttyfd != -1) {
1824 strlcat(buf, ",", sizeof buf);
1825 strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf);
1829 strlcpy(buf, "notty", sizeof buf);
1834 session_proctitle(Session *s)
1837 error("no user for session %d", s->self);
1839 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
1843 session_setup_x11fwd(Session *s)
1846 char display[512], auth_display[512];
1847 char hostname[MAXHOSTNAMELEN];
1849 if (no_x11_forwarding_flag) {
1850 packet_send_debug("X11 forwarding disabled in user configuration file.");
1853 if (!options.x11_forwarding) {
1854 debug("X11 forwarding disabled in server configuration file.");
1857 if (!options.xauth_location ||
1858 (stat(options.xauth_location, &st) == -1)) {
1859 packet_send_debug("No xauth program; cannot forward with spoofing.");
1862 if (options.use_login) {
1863 packet_send_debug("X11 forwarding disabled; "
1864 "not compatible with UseLogin=yes.");
1867 if (s->display != NULL) {
1868 debug("X11 display already set.");
1871 s->display_number = x11_create_display_inet(options.x11_display_offset,
1872 options.x11_use_localhost, s->single_connection);
1873 if (s->display_number == -1) {
1874 debug("x11_create_display_inet failed.");
1878 /* Set up a suitable value for the DISPLAY variable. */
1879 if (gethostname(hostname, sizeof(hostname)) < 0)
1880 fatal("gethostname: %.100s", strerror(errno));
1882 * auth_display must be used as the displayname when the
1883 * authorization entry is added with xauth(1). This will be
1884 * different than the DISPLAY string for localhost displays.
1886 if (options.x11_use_localhost) {
1887 snprintf(display, sizeof display, "localhost:%d.%d",
1888 s->display_number, s->screen);
1889 snprintf(auth_display, sizeof auth_display, "unix:%d.%d",
1890 s->display_number, s->screen);
1891 s->display = xstrdup(display);
1892 s->auth_display = xstrdup(auth_display);
1894 #ifdef IPADDR_IN_DISPLAY
1896 struct in_addr my_addr;
1898 he = gethostbyname(hostname);
1900 error("Can't get IP address for X11 DISPLAY.");
1901 packet_send_debug("Can't get IP address for X11 DISPLAY.");
1904 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
1905 snprintf(display, sizeof display, "%.50s:%d.%d", inet_ntoa(my_addr),
1906 s->display_number, s->screen);
1908 snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
1909 s->display_number, s->screen);
1911 s->display = xstrdup(display);
1912 s->auth_display = xstrdup(display);
1919 do_authenticated2(Authctxt *authctxt)
1921 server_loop2(authctxt);