1 /* $OpenBSD: session.c,v 1.274 2014/07/15 15:54:14 millert Exp $ */
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 #include <sys/types.h>
39 #include <sys/param.h>
40 #ifdef HAVE_SYS_STAT_H
41 # include <sys/stat.h>
43 #include <sys/socket.h>
47 #include <arpa/inet.h>
64 #include "openbsd-compat/sys-queue.h"
83 #include "auth-options.h"
85 #include "pathnames.h"
90 #include "serverloop.h"
94 #include "monitor_wrap.h"
97 #if defined(KRB5) && defined(USE_AFS)
102 #include <selinux/selinux.h>
105 #define IS_INTERNAL_SFTP(c) \
106 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
107 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
108 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
109 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
113 Session *session_new(void);
114 void session_set_fds(Session *, int, int, int, int, int);
115 void session_pty_cleanup(Session *);
116 void session_proctitle(Session *);
117 int session_setup_x11fwd(Session *);
118 int do_exec_pty(Session *, const char *);
119 int do_exec_no_pty(Session *, const char *);
120 int do_exec(Session *, const char *);
121 void do_login(Session *, const char *);
122 #ifdef LOGIN_NEEDS_UTMPX
123 static void do_pre_login(Session *s);
125 void do_child(Session *, const char *);
127 int check_quietlogin(Session *, const char *);
129 static void do_authenticated1(Authctxt *);
130 static void do_authenticated2(Authctxt *);
132 static int session_pty_req(Session *);
135 extern ServerOptions options;
136 extern char *__progname;
137 extern int log_stderr;
138 extern int debug_flag;
139 extern u_int utmp_len;
140 extern int startup_pipe;
141 extern void destroy_sensitive_data(void);
142 extern Buffer loginmsg;
144 /* original command from peer. */
145 const char *original_command = NULL;
148 static int sessions_first_unused = -1;
149 static int sessions_nalloc = 0;
150 static Session *sessions = NULL;
152 #define SUBSYSTEM_NONE 0
153 #define SUBSYSTEM_EXT 1
154 #define SUBSYSTEM_INT_SFTP 2
155 #define SUBSYSTEM_INT_SFTP_ERROR 3
157 #ifdef HAVE_LOGIN_CAP
161 static int is_child = 0;
163 /* Name and directory of socket for authentication agent forwarding. */
164 static char *auth_sock_name = NULL;
165 static char *auth_sock_dir = NULL;
167 /* removes the agent forwarding socket */
170 auth_sock_cleanup_proc(struct passwd *pw)
172 if (auth_sock_name != NULL) {
173 temporarily_use_uid(pw);
174 unlink(auth_sock_name);
175 rmdir(auth_sock_dir);
176 auth_sock_name = NULL;
182 auth_input_request_forwarding(struct passwd * pw)
187 if (auth_sock_name != NULL) {
188 error("authentication forwarding requested twice.");
192 /* Temporarily drop privileged uid for mkdir/bind. */
193 temporarily_use_uid(pw);
195 /* Allocate a buffer for the socket name, and format the name. */
196 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
198 /* Create private directory for socket */
199 if (mkdtemp(auth_sock_dir) == NULL) {
200 packet_send_debug("Agent forwarding disabled: "
201 "mkdtemp() failed: %.100s", strerror(errno));
204 auth_sock_dir = NULL;
208 xasprintf(&auth_sock_name, "%s/agent.%ld",
209 auth_sock_dir, (long) getpid());
211 /* Start a Unix listener on auth_sock_name. */
212 sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0);
214 /* Restore the privileged uid. */
217 /* Check for socket/bind/listen failure. */
221 /* Allocate a channel for the authentication agent socket. */
222 /* this shouldn't matter if its hpn or not - cjr */
223 nc = channel_new("auth socket",
224 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
225 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
226 0, "auth socket", 1);
227 nc->path = xstrdup(auth_sock_name);
231 free(auth_sock_name);
232 if (auth_sock_dir != NULL) {
233 rmdir(auth_sock_dir);
238 auth_sock_name = NULL;
239 auth_sock_dir = NULL;
244 display_loginmsg(void)
246 if (buffer_len(&loginmsg) > 0) {
247 buffer_append(&loginmsg, "\0", 1);
248 printf("%s", (char *)buffer_ptr(&loginmsg));
249 buffer_clear(&loginmsg);
254 do_authenticated(Authctxt *authctxt)
256 setproctitle("%s", authctxt->pw->pw_name);
258 /* setup the channel layer */
259 /* XXX - streamlocal? */
260 if (no_port_forwarding_flag ||
261 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
262 channel_disable_adm_local_opens();
264 channel_permit_all_opens();
269 do_authenticated2(authctxt);
271 do_authenticated1(authctxt);
273 do_cleanup(authctxt);
277 * Prepares for an interactive session. This is called after the user has
278 * been successfully authenticated. During this message exchange, pseudo
279 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
280 * are requested, etc.
283 do_authenticated1(Authctxt *authctxt)
287 int success, type, screen_flag;
288 int enable_compression_after_reply = 0;
289 u_int proto_len, data_len, dlen, compression_level = 0;
293 error("no more sessions");
296 s->authctxt = authctxt;
297 s->pw = authctxt->pw;
300 * We stay in this loop until the client requests to execute a shell
306 /* Get a packet from the client. */
307 type = packet_read();
309 /* Process the packet. */
311 case SSH_CMSG_REQUEST_COMPRESSION:
312 compression_level = packet_get_int();
314 if (compression_level < 1 || compression_level > 9) {
315 packet_send_debug("Received invalid compression level %d.",
319 if (options.compression == COMP_NONE) {
320 debug2("compression disabled");
323 /* Enable compression after we have responded with SUCCESS. */
324 enable_compression_after_reply = 1;
328 case SSH_CMSG_REQUEST_PTY:
329 success = session_pty_req(s);
332 case SSH_CMSG_X11_REQUEST_FORWARDING:
333 s->auth_proto = packet_get_string(&proto_len);
334 s->auth_data = packet_get_string(&data_len);
336 screen_flag = packet_get_protocol_flags() &
337 SSH_PROTOFLAG_SCREEN_NUMBER;
338 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
340 if (packet_remaining() == 4) {
342 debug2("Buggy client: "
343 "X11 screen flag missing");
344 s->screen = packet_get_int();
349 success = session_setup_x11fwd(s);
353 s->auth_proto = NULL;
358 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
359 if (!options.allow_agent_forwarding ||
360 no_agent_forwarding_flag || compat13) {
361 debug("Authentication agent forwarding not permitted for this authentication.");
364 debug("Received authentication agent forwarding request.");
365 success = auth_input_request_forwarding(s->pw);
368 case SSH_CMSG_PORT_FORWARD_REQUEST:
369 if (no_port_forwarding_flag) {
370 debug("Port forwarding not permitted for this authentication.");
373 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
374 debug("Port forwarding not permitted.");
377 debug("Received TCP/IP port forwarding request.");
378 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
379 &options.fwd_opts) < 0) {
380 debug("Port forwarding failed.");
386 case SSH_CMSG_MAX_PACKET_SIZE:
387 if (packet_set_maxsize(packet_get_int()) > 0)
391 case SSH_CMSG_EXEC_SHELL:
392 case SSH_CMSG_EXEC_CMD:
393 if (type == SSH_CMSG_EXEC_CMD) {
394 command = packet_get_string(&dlen);
395 debug("Exec command '%.500s'", command);
396 if (do_exec(s, command) != 0)
398 "command execution failed");
401 if (do_exec(s, NULL) != 0)
403 "shell execution failed");
411 * Any unknown messages in this phase are ignored,
412 * and a failure message is returned.
414 logit("Unknown packet type received after authentication: %d", type);
416 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
420 /* Enable compression now that we have replied if appropriate. */
421 if (enable_compression_after_reply) {
422 enable_compression_after_reply = 0;
423 packet_start_compression(compression_level);
430 * This is called to fork and execute a command when we have no tty. This
431 * will call do_child from the child, and server_loop from the parent after
432 * setting up file descriptors and such.
435 do_exec_no_pty(Session *s, const char *command)
440 int pin[2], pout[2], perr[2];
443 fatal("do_exec_no_pty: no session");
445 /* Allocate pipes for communicating with the program. */
447 error("%s: pipe in: %.100s", __func__, strerror(errno));
450 if (pipe(pout) < 0) {
451 error("%s: pipe out: %.100s", __func__, strerror(errno));
456 if (pipe(perr) < 0) {
457 error("%s: pipe err: %.100s", __func__,
466 int inout[2], err[2];
469 fatal("do_exec_no_pty: no session");
471 /* Uses socket pairs to communicate with the program. */
472 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
473 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
476 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
477 error("%s: socketpair #2: %.100s", __func__,
485 session_proctitle(s);
487 /* Fork the child. */
488 switch ((pid = fork())) {
490 error("%s: fork: %.100s", __func__, strerror(errno));
508 /* Child. Reinitialize the log since the pid has changed. */
509 log_init(__progname, options.log_level,
510 options.log_facility, log_stderr);
513 * Create a new session and process group since the 4.4BSD
514 * setlogin() affects the entire process group.
517 error("setsid failed: %.100s", strerror(errno));
521 * Redirect stdin. We close the parent side of the socket
522 * pair, and make the child side the standard input.
525 if (dup2(pin[0], 0) < 0)
526 perror("dup2 stdin");
529 /* Redirect stdout. */
531 if (dup2(pout[1], 1) < 0)
532 perror("dup2 stdout");
535 /* Redirect stderr. */
537 if (dup2(perr[1], 2) < 0)
538 perror("dup2 stderr");
542 * Redirect stdin, stdout, and stderr. Stdin and stdout will
543 * use the same socket, as some programs (particularly rdist)
544 * seem to depend on it.
548 if (dup2(inout[0], 0) < 0) /* stdin */
549 perror("dup2 stdin");
550 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
551 perror("dup2 stdout");
553 if (dup2(err[0], 2) < 0) /* stderr */
554 perror("dup2 stderr");
560 cray_init_job(s->pw); /* set up cray jid and tmpdir */
563 /* Do processing for the child (exec command etc). */
564 do_child(s, command);
571 signal(WJSIGNAL, cray_job_termination_handler);
574 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
578 /* Set interactive/non-interactive mode. */
579 packet_set_interactive(s->display != NULL,
580 options.ip_qos_interactive, options.ip_qos_bulk);
583 * Clear loginmsg, since it's the child's responsibility to display
584 * it to the user, otherwise multiple sessions may accumulate
585 * multiple copies of the login messages.
587 buffer_clear(&loginmsg);
590 /* We are the parent. Close the child sides of the pipes. */
596 session_set_fds(s, pin[1], pout[0], perr[0],
599 /* Enter the interactive session. */
600 server_loop(pid, pin[1], pout[0], perr[0]);
601 /* server_loop has closed pin[1], pout[0], and perr[0]. */
604 /* We are the parent. Close the child sides of the socket pairs. */
609 * Enter the interactive session. Note: server_loop must be able to
610 * handle the case that fdin and fdout are the same.
613 session_set_fds(s, inout[1], inout[1], err[1],
616 server_loop(pid, inout[1], inout[1], err[1]);
617 /* server_loop has closed inout[1] and err[1]. */
624 * This is called to fork and execute a command when we have a tty. This
625 * will call do_child from the child, and server_loop from the parent after
626 * setting up file descriptors, controlling tty, updating wtmp, utmp,
627 * lastlog, and other such operations.
630 do_exec_pty(Session *s, const char *command)
632 int fdout, ptyfd, ttyfd, ptymaster;
636 fatal("do_exec_pty: no session");
641 * Create another descriptor of the pty master side for use as the
642 * standard input. We could use the original descriptor, but this
643 * simplifies code in server_loop. The descriptor is bidirectional.
644 * Do this before forking (and cleanup in the child) so as to
645 * detect and gracefully fail out-of-fd conditions.
647 if ((fdout = dup(ptyfd)) < 0) {
648 error("%s: dup #1: %s", __func__, strerror(errno));
653 /* we keep a reference to the pty master */
654 if ((ptymaster = dup(ptyfd)) < 0) {
655 error("%s: dup #2: %s", __func__, strerror(errno));
662 /* Fork the child. */
663 switch ((pid = fork())) {
665 error("%s: fork: %.100s", __func__, strerror(errno));
677 /* Child. Reinitialize the log because the pid has changed. */
678 log_init(__progname, options.log_level,
679 options.log_facility, log_stderr);
680 /* Close the master side of the pseudo tty. */
683 /* Make the pseudo tty our controlling tty. */
684 pty_make_controlling_tty(&ttyfd, s->tty);
686 /* Redirect stdin/stdout/stderr from the pseudo tty. */
687 if (dup2(ttyfd, 0) < 0)
688 error("dup2 stdin: %s", strerror(errno));
689 if (dup2(ttyfd, 1) < 0)
690 error("dup2 stdout: %s", strerror(errno));
691 if (dup2(ttyfd, 2) < 0)
692 error("dup2 stderr: %s", strerror(errno));
694 /* Close the extra descriptor for the pseudo tty. */
697 /* record login, etc. similar to login(1) */
699 if (!(options.use_login && command == NULL)) {
701 cray_init_job(s->pw); /* set up cray jid and tmpdir */
703 do_login(s, command);
705 # ifdef LOGIN_NEEDS_UTMPX
711 * Do common processing for the child, such as execing
714 do_child(s, command);
721 signal(WJSIGNAL, cray_job_termination_handler);
724 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
729 /* Parent. Close the slave side of the pseudo tty. */
732 /* Enter interactive session. */
733 s->ptymaster = ptymaster;
734 packet_set_interactive(1,
735 options.ip_qos_interactive, options.ip_qos_bulk);
737 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
739 server_loop(pid, ptyfd, fdout, -1);
740 /* server_loop _has_ closed ptyfd and fdout. */
745 #ifdef LOGIN_NEEDS_UTMPX
747 do_pre_login(Session *s)
750 struct sockaddr_storage from;
751 pid_t pid = getpid();
754 * Get IP address of client. If the connection is not a socket, let
755 * the address be 0.0.0.0.
757 memset(&from, 0, sizeof(from));
758 fromlen = sizeof(from);
759 if (packet_connection_is_on_socket()) {
760 if (getpeername(packet_get_connection_in(),
761 (struct sockaddr *)&from, &fromlen) < 0) {
762 debug("getpeername: %.100s", strerror(errno));
767 record_utmp_only(pid, s->tty, s->pw->pw_name,
768 get_remote_name_or_ip(utmp_len, options.use_dns),
769 (struct sockaddr *)&from, fromlen);
774 * This is called to fork and execute a command. If another command is
775 * to be forced, execute that instead.
778 do_exec(Session *s, const char *command)
781 const char *forced = NULL;
782 char session_type[1024], *tty = NULL;
784 if (options.adm_forced_command) {
785 original_command = command;
786 command = options.adm_forced_command;
788 } else if (forced_command) {
789 original_command = command;
790 command = forced_command;
791 forced = "(key-option)";
793 if (forced != NULL) {
794 if (IS_INTERNAL_SFTP(command)) {
795 s->is_subsystem = s->is_subsystem ?
796 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
797 } else if (s->is_subsystem)
798 s->is_subsystem = SUBSYSTEM_EXT;
799 snprintf(session_type, sizeof(session_type),
800 "forced-command %s '%.900s'", forced, command);
801 } else if (s->is_subsystem) {
802 snprintf(session_type, sizeof(session_type),
803 "subsystem '%.900s'", s->subsys);
804 } else if (command == NULL) {
805 snprintf(session_type, sizeof(session_type), "shell");
807 /* NB. we don't log unforced commands to preserve privacy */
808 snprintf(session_type, sizeof(session_type), "command");
811 if (s->ttyfd != -1) {
813 if (strncmp(tty, "/dev/", 5) == 0)
817 verbose("Starting session: %s%s%s for %s from %.200s port %d",
819 tty == NULL ? "" : " on ",
820 tty == NULL ? "" : tty,
825 #ifdef SSH_AUDIT_EVENTS
827 PRIVSEP(audit_run_command(command));
828 else if (s->ttyfd == -1) {
829 char *shell = s->pw->pw_shell;
831 if (shell[0] == '\0') /* empty shell means /bin/sh */
833 PRIVSEP(audit_run_command(shell));
837 ret = do_exec_pty(s, command);
839 ret = do_exec_no_pty(s, command);
841 original_command = NULL;
844 * Clear loginmsg: it's the child's responsibility to display
845 * it to the user, otherwise multiple sessions may accumulate
846 * multiple copies of the login messages.
848 buffer_clear(&loginmsg);
853 /* administrative, login(1)-like work */
855 do_login(Session *s, const char *command)
858 struct sockaddr_storage from;
859 struct passwd * pw = s->pw;
860 pid_t pid = getpid();
863 * Get IP address of client. If the connection is not a socket, let
864 * the address be 0.0.0.0.
866 memset(&from, 0, sizeof(from));
867 fromlen = sizeof(from);
868 if (packet_connection_is_on_socket()) {
869 if (getpeername(packet_get_connection_in(),
870 (struct sockaddr *)&from, &fromlen) < 0) {
871 debug("getpeername: %.100s", strerror(errno));
876 /* Record that there was a login on that tty from the remote host. */
878 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
879 get_remote_name_or_ip(utmp_len,
881 (struct sockaddr *)&from, fromlen);
885 * If password change is needed, do it now.
886 * This needs to occur before the ~/.hushlogin check.
888 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
891 s->authctxt->force_pwchange = 0;
892 /* XXX - signal [net] parent to enable forwardings */
896 if (check_quietlogin(s, command))
905 * Display the message of the day.
912 #ifdef HAVE_LOGIN_CAP
916 #ifdef HAVE_LOGIN_CAP
917 fname = login_getcapstr(lc, "copyright", NULL, NULL);
918 if (fname != NULL && (f = fopen(fname, "r")) != NULL) {
919 while (fgets(buf, sizeof(buf), f) != NULL)
923 #endif /* HAVE_LOGIN_CAP */
924 (void)printf("%s\n\t%s %s\n",
925 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
926 "The Regents of the University of California. ",
927 "All rights reserved.");
931 if (options.print_motd) {
932 #ifdef HAVE_LOGIN_CAP
933 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
936 f = fopen("/etc/motd", "r");
939 while (fgets(buf, sizeof(buf), f))
948 * Check for quiet login, either .hushlogin or command given.
951 check_quietlogin(Session *s, const char *command)
954 struct passwd *pw = s->pw;
957 /* Return 1 if .hushlogin exists or a command given. */
960 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
961 #ifdef HAVE_LOGIN_CAP
962 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
965 if (stat(buf, &st) >= 0)
972 * Sets the value of the given variable in the environment. If the variable
973 * already exists, its value is overridden.
976 child_set_env(char ***envp, u_int *envsizep, const char *name,
983 if (strchr(name, '=') != NULL) {
984 error("Invalid environment variable \"%.100s\"", name);
989 * If we're passed an uninitialized list, allocate a single null
990 * entry before continuing.
992 if (*envp == NULL && *envsizep == 0) {
993 *envp = xmalloc(sizeof(char *));
999 * Find the slot where the value should be stored. If the variable
1000 * already exists, we reuse the slot; otherwise we append a new slot
1001 * at the end of the array, expanding if necessary.
1004 namelen = strlen(name);
1005 for (i = 0; env[i]; i++)
1006 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1009 /* Reuse the slot. */
1012 /* New variable. Expand if necessary. */
1013 envsize = *envsizep;
1014 if (i >= envsize - 1) {
1015 if (envsize >= 1000)
1016 fatal("child_set_env: too many env vars");
1018 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1019 *envsizep = envsize;
1021 /* Need to set the NULL pointer at end of array beyond the new slot. */
1025 /* Allocate space and format the variable in the appropriate slot. */
1026 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1027 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1031 * Reads environment variables from the given file and adds/overrides them
1032 * into the environment. If the file does not exist, this does nothing.
1033 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1034 * and assignments of the form name=value. No other forms are allowed.
1037 read_environment_file(char ***env, u_int *envsize,
1038 const char *filename)
1045 f = fopen(filename, "r");
1049 while (fgets(buf, sizeof(buf), f)) {
1050 if (++lineno > 1000)
1051 fatal("Too many lines in environment file %s", filename);
1052 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1054 if (!*cp || *cp == '#' || *cp == '\n')
1057 cp[strcspn(cp, "\n")] = '\0';
1059 value = strchr(cp, '=');
1060 if (value == NULL) {
1061 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1066 * Replace the equals sign by nul, and advance value to
1071 child_set_env(env, envsize, cp, value);
1076 #ifdef HAVE_ETC_DEFAULT_LOGIN
1078 * Return named variable from specified environment, or NULL if not present.
1081 child_get_env(char **env, const char *name)
1087 for (i=0; env[i] != NULL; i++)
1088 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1089 return(env[i] + len + 1);
1094 * Read /etc/default/login.
1095 * We pick up the PATH (or SUPATH for root) and UMASK.
1098 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1100 char **tmpenv = NULL, *var;
1101 u_int i, tmpenvsize = 0;
1105 * We don't want to copy the whole file to the child's environment,
1106 * so we use a temporary environment and copy the variables we're
1109 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1115 var = child_get_env(tmpenv, "SUPATH");
1117 var = child_get_env(tmpenv, "PATH");
1119 child_set_env(env, envsize, "PATH", var);
1121 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1122 if (sscanf(var, "%5lo", &mask) == 1)
1123 umask((mode_t)mask);
1125 for (i = 0; tmpenv[i] != NULL; i++)
1129 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1132 copy_environment(char **source, char ***env, u_int *envsize)
1134 char *var_name, *var_val;
1140 for(i = 0; source[i] != NULL; i++) {
1141 var_name = xstrdup(source[i]);
1142 if ((var_val = strstr(var_name, "=")) == NULL) {
1148 debug3("Copy environment: %s=%s", var_name, var_val);
1149 child_set_env(env, envsize, var_name, var_val);
1156 do_setup_env(Session *s, const char *shell)
1161 struct passwd *pw = s->pw;
1162 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1165 extern char **environ;
1172 /* Initialize the environment. */
1174 env = xcalloc(envsize, sizeof(char *));
1179 * The Windows environment contains some setting which are
1180 * important for a running system. They must not be dropped.
1185 p = fetch_windows_environment();
1186 copy_environment(p, &env, &envsize);
1187 free_windows_environment(p);
1192 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1195 /* Allow any GSSAPI methods that we've used to alter
1196 * the childs environment as they see fit
1198 ssh_gssapi_do_child(&env, &envsize);
1201 if (!options.use_login) {
1202 /* Set basic environment. */
1203 for (i = 0; i < s->num_env; i++)
1204 child_set_env(&env, &envsize, s->env[i].name,
1207 child_set_env(&env, &envsize, "USER", pw->pw_name);
1208 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1210 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1212 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1213 snprintf(buf, sizeof buf, "%.200s/%.50s",
1214 _PATH_MAILDIR, pw->pw_name);
1215 child_set_env(&env, &envsize, "MAIL", buf);
1216 #ifdef HAVE_LOGIN_CAP
1217 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1218 child_set_env(&env, &envsize, "TERM", "su");
1220 environ = xmalloc(sizeof(char *));
1222 (void) setusercontext(lc, pw, pw->pw_uid,
1223 LOGIN_SETENV|LOGIN_SETPATH);
1224 copy_environment(environ, &env, &envsize);
1227 * This interferes with libc's management of the environment
1228 * in horrible ways that can cause sshd to crash.
1230 for (var = environ; *var != NULL; ++var)
1235 #else /* HAVE_LOGIN_CAP */
1236 # ifndef HAVE_CYGWIN
1238 * There's no standard path on Windows. The path contains
1239 * important components pointing to the system directories,
1240 * needed for loading shared libraries. So the path better
1241 * remains intact here.
1243 # ifdef HAVE_ETC_DEFAULT_LOGIN
1244 read_etc_default_login(&env, &envsize, pw->pw_uid);
1245 path = child_get_env(env, "PATH");
1246 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1247 if (path == NULL || *path == '\0') {
1248 child_set_env(&env, &envsize, "PATH",
1249 s->pw->pw_uid == 0 ?
1250 SUPERUSER_PATH : _PATH_STDPATH);
1252 # endif /* HAVE_CYGWIN */
1253 #endif /* HAVE_LOGIN_CAP */
1255 /* Normal systems set SHELL by default. */
1256 child_set_env(&env, &envsize, "SHELL", shell);
1259 /* Set custom environment options from RSA authentication. */
1260 if (!options.use_login) {
1261 while (custom_environment) {
1262 struct envstring *ce = custom_environment;
1265 for (i = 0; str[i] != '=' && str[i]; i++)
1267 if (str[i] == '=') {
1269 child_set_env(&env, &envsize, str, str + i + 1);
1271 custom_environment = ce->next;
1277 /* SSH_CLIENT deprecated */
1278 snprintf(buf, sizeof buf, "%.50s %d %d",
1279 get_remote_ipaddr(), get_remote_port(), get_local_port());
1280 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1282 laddr = get_local_ipaddr(packet_get_connection_in());
1283 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1284 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1286 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1289 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1291 child_set_env(&env, &envsize, "TERM", s->term);
1293 child_set_env(&env, &envsize, "DISPLAY", s->display);
1294 if (original_command)
1295 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1299 if (cray_tmpdir[0] != '\0')
1300 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1301 #endif /* _UNICOS */
1304 * Since we clear KRB5CCNAME at startup, if it's set now then it
1305 * must have been set by a native authentication method (eg AIX or
1306 * SIA), so copy it to the child.
1311 if ((cp = getenv("KRB5CCNAME")) != NULL)
1312 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1319 if ((cp = getenv("AUTHSTATE")) != NULL)
1320 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1321 read_environment_file(&env, &envsize, "/etc/environment");
1325 if (s->authctxt->krb5_ccname)
1326 child_set_env(&env, &envsize, "KRB5CCNAME",
1327 s->authctxt->krb5_ccname);
1331 * Pull in any environment variables that may have
1334 if (options.use_pam) {
1337 p = fetch_pam_child_environment();
1338 copy_environment(p, &env, &envsize);
1339 free_pam_environment(p);
1341 p = fetch_pam_environment();
1342 copy_environment(p, &env, &envsize);
1343 free_pam_environment(p);
1345 #endif /* USE_PAM */
1347 if (auth_sock_name != NULL)
1348 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1351 /* read $HOME/.ssh/environment. */
1352 if (options.permit_user_env && !options.use_login) {
1353 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1354 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1355 read_environment_file(&env, &envsize, buf);
1358 /* dump the environment */
1359 fprintf(stderr, "Environment:\n");
1360 for (i = 0; env[i]; i++)
1361 fprintf(stderr, " %.200s\n", env[i]);
1367 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1368 * first in this order).
1371 do_rc_files(Session *s, const char *shell)
1379 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1381 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1382 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1383 !no_user_rc && options.permit_user_rc &&
1384 stat(_PATH_SSH_USER_RC, &st) >= 0) {
1385 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1386 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1388 fprintf(stderr, "Running %s\n", cmd);
1389 f = popen(cmd, "w");
1392 fprintf(f, "%s %s\n", s->auth_proto,
1396 fprintf(stderr, "Could not run %s\n",
1398 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1400 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1401 _PATH_SSH_SYSTEM_RC);
1402 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1405 fprintf(f, "%s %s\n", s->auth_proto,
1409 fprintf(stderr, "Could not run %s\n",
1410 _PATH_SSH_SYSTEM_RC);
1411 } else if (do_xauth && options.xauth_location != NULL) {
1412 /* Add authority data to .Xauthority if appropriate. */
1415 "Running %.500s remove %.100s\n",
1416 options.xauth_location, s->auth_display);
1418 "%.500s add %.100s %.100s %.100s\n",
1419 options.xauth_location, s->auth_display,
1420 s->auth_proto, s->auth_data);
1422 snprintf(cmd, sizeof cmd, "%s -q -",
1423 options.xauth_location);
1424 f = popen(cmd, "w");
1426 fprintf(f, "remove %s\n",
1428 fprintf(f, "add %s %s %s\n",
1429 s->auth_display, s->auth_proto,
1433 fprintf(stderr, "Could not run %s\n",
1440 do_nologin(struct passwd *pw)
1443 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1446 #ifdef HAVE_LOGIN_CAP
1447 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1449 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1451 if (pw->pw_uid == 0)
1455 if (stat(nl, &sb) == -1) {
1461 /* /etc/nologin exists. Print its contents if we can and exit. */
1462 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1463 if ((f = fopen(nl, "r")) != NULL) {
1464 while (fgets(buf, sizeof(buf), f))
1472 * Chroot into a directory after checking it for safety: all path components
1473 * must be root-owned directories with strict permissions.
1476 safely_chroot(const char *path, uid_t uid)
1479 char component[MAXPATHLEN];
1483 fatal("chroot path does not begin at root");
1484 if (strlen(path) >= sizeof(component))
1485 fatal("chroot path too long");
1488 * Descend the path, checking that each component is a
1489 * root-owned directory with strict permissions.
1491 for (cp = path; cp != NULL;) {
1492 if ((cp = strchr(cp, '/')) == NULL)
1493 strlcpy(component, path, sizeof(component));
1496 memcpy(component, path, cp - path);
1497 component[cp - path] = '\0';
1500 debug3("%s: checking '%s'", __func__, component);
1502 if (stat(component, &st) != 0)
1503 fatal("%s: stat(\"%s\"): %s", __func__,
1504 component, strerror(errno));
1505 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1506 fatal("bad ownership or modes for chroot "
1507 "directory %s\"%s\"",
1508 cp == NULL ? "" : "component ", component);
1509 if (!S_ISDIR(st.st_mode))
1510 fatal("chroot path %s\"%s\" is not a directory",
1511 cp == NULL ? "" : "component ", component);
1515 if (chdir(path) == -1)
1516 fatal("Unable to chdir to chroot path \"%s\": "
1517 "%s", path, strerror(errno));
1518 if (chroot(path) == -1)
1519 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1520 if (chdir("/") == -1)
1521 fatal("%s: chdir(/) after chroot: %s",
1522 __func__, strerror(errno));
1523 verbose("Changed root directory to \"%s\"", path);
1526 /* Set login name, uid, gid, and groups. */
1528 do_setusercontext(struct passwd *pw)
1530 char *chroot_path, *tmp;
1532 int doing_chroot = 0;
1535 platform_setusercontext(pw);
1537 if (platform_privileged_uidswap()) {
1538 #ifdef HAVE_LOGIN_CAP
1539 if (setusercontext(lc, pw, pw->pw_uid,
1540 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1541 perror("unable to set user context");
1545 if (setlogin(pw->pw_name) < 0)
1546 error("setlogin failed: %s", strerror(errno));
1547 if (setgid(pw->pw_gid) < 0) {
1551 /* Initialize the group list. */
1552 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1553 perror("initgroups");
1559 platform_setusercontext_post_groups(pw);
1561 if (options.chroot_directory != NULL &&
1562 strcasecmp(options.chroot_directory, "none") != 0) {
1563 tmp = tilde_expand_filename(options.chroot_directory,
1565 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1566 "u", pw->pw_name, (char *)NULL);
1567 safely_chroot(chroot_path, pw->pw_uid);
1570 /* Make sure we don't attempt to chroot again */
1571 free(options.chroot_directory);
1572 options.chroot_directory = NULL;
1578 #ifdef HAVE_LOGIN_CAP
1579 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1580 perror("unable to set user context (setuser)");
1584 * FreeBSD's setusercontext() will not apply the user's
1585 * own umask setting unless running with the user's UID.
1587 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK);
1590 /* In a chroot environment, the set_id() will always fail; typically
1591 * because of the lack of necessary authentication services and runtime
1592 * such as ./usr/lib/libiaf.so, ./usr/lib/libpam.so.1, and ./etc/passwd
1593 * We skip it in the internal sftp chroot case.
1594 * We'll lose auditing and ACLs but permanently_set_uid will
1595 * take care of the rest.
1597 if ((doing_chroot == 0) && set_id(pw->pw_name) != 0) {
1598 fatal("set_id(%s) Failed", pw->pw_name);
1600 # endif /* USE_LIBIAF */
1601 /* Permanently switch to the desired uid. */
1602 permanently_set_uid(pw);
1604 } else if (options.chroot_directory != NULL &&
1605 strcasecmp(options.chroot_directory, "none") != 0) {
1606 fatal("server lacks privileges to chroot to ChrootDirectory");
1609 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1610 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1614 do_pwchange(Session *s)
1617 fprintf(stderr, "WARNING: Your password has expired.\n");
1618 if (s->ttyfd != -1) {
1620 "You must change your password now and login again!\n");
1624 #ifdef PASSWD_NEEDS_USERNAME
1625 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1628 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1633 "Password change required but no TTY available.\n");
1639 launch_login(struct passwd *pw, const char *hostname)
1641 /* Launch login(1). */
1643 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1644 #ifdef xxxLOGIN_NEEDS_TERM
1645 (s->term ? s->term : "unknown"),
1646 #endif /* LOGIN_NEEDS_TERM */
1647 #ifdef LOGIN_NO_ENDOPT
1648 "-p", "-f", pw->pw_name, (char *)NULL);
1650 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1653 /* Login couldn't be executed, die. */
1660 child_close_fds(void)
1662 extern AuthenticationConnection *auth_conn;
1665 ssh_close_authentication_connection(auth_conn);
1669 if (packet_get_connection_in() == packet_get_connection_out())
1670 close(packet_get_connection_in());
1672 close(packet_get_connection_in());
1673 close(packet_get_connection_out());
1676 * Close all descriptors related to channels. They will still remain
1677 * open in the parent.
1679 /* XXX better use close-on-exec? -markus */
1680 channel_close_all();
1683 * Close any extra file descriptors. Note that there may still be
1684 * descriptors left by system functions. They will be closed later.
1689 * Close any extra open file descriptors so that we don't have them
1690 * hanging around in clients. Note that we want to do this after
1691 * initgroups, because at least on Solaris 2.3 it leaves file
1694 closefrom(STDERR_FILENO + 1);
1698 * Performs common processing for the child, such as setting up the
1699 * environment, closing extra file descriptors, setting the user and group
1700 * ids, and executing the command or shell.
1704 do_child(Session *s, const char *command)
1706 extern char **environ;
1708 char *argv[ARGV_MAX];
1709 const char *shell, *shell0, *hostname = NULL;
1710 struct passwd *pw = s->pw;
1713 /* remove hostkey from the child's memory */
1714 destroy_sensitive_data();
1716 /* Force a password change */
1717 if (s->authctxt->force_pwchange) {
1718 do_setusercontext(pw);
1724 /* login(1) is only called if we execute the login shell */
1725 if (options.use_login && command != NULL)
1726 options.use_login = 0;
1729 cray_setup(pw->pw_uid, pw->pw_name, command);
1730 #endif /* _UNICOS */
1733 * Login(1) does this as well, and it needs uid 0 for the "-h"
1734 * switch, so we let login(1) to this for us.
1736 if (!options.use_login) {
1738 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1739 if (!check_quietlogin(s, command))
1741 #else /* HAVE_OSF_SIA */
1742 /* When PAM is enabled we rely on it to do the nologin check */
1743 if (!options.use_pam)
1745 do_setusercontext(pw);
1747 * PAM session modules in do_setusercontext may have
1748 * generated messages, so if this in an interactive
1749 * login then display them too.
1751 if (!check_quietlogin(s, command))
1753 #endif /* HAVE_OSF_SIA */
1757 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1758 debug3("PAM session not opened, exiting");
1765 * Get the shell from the password data. An empty shell field is
1766 * legal, and means /bin/sh.
1768 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1771 * Make sure $SHELL points to the shell from the password file,
1772 * even if shell is overridden from login.conf
1774 env = do_setup_env(s, shell);
1776 #ifdef HAVE_LOGIN_CAP
1777 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1780 /* we have to stash the hostname before we close our socket. */
1781 if (options.use_login)
1782 hostname = get_remote_name_or_ip(utmp_len,
1785 * Close the connection descriptors; note that this is the child, and
1786 * the server will still have the socket open, and it is important
1787 * that we do not shutdown it. Note that the descriptors cannot be
1788 * closed before building the environment, as we call
1789 * get_remote_ipaddr there.
1794 * Must take new environment into use so that .ssh/rc,
1795 * /etc/ssh/sshrc and xauth are run in the proper environment.
1799 #if defined(KRB5) && defined(USE_AFS)
1801 * At this point, we check to see if AFS is active and if we have
1802 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1803 * if we can (and need to) extend the ticket into an AFS token. If
1804 * we don't do this, we run into potential problems if the user's
1805 * home directory is in AFS and it's not world-readable.
1808 if (options.kerberos_get_afs_token && k_hasafs() &&
1809 (s->authctxt->krb5_ctx != NULL)) {
1812 debug("Getting AFS token");
1816 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1817 krb5_afslog(s->authctxt->krb5_ctx,
1818 s->authctxt->krb5_fwd_ccache, cell, NULL);
1820 krb5_afslog_home(s->authctxt->krb5_ctx,
1821 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1825 /* Change current directory to the user's home directory. */
1826 if (chdir(pw->pw_dir) < 0) {
1827 /* Suppress missing homedir warning for chroot case */
1828 #ifdef HAVE_LOGIN_CAP
1829 r = login_getcapbool(lc, "requirehome", 0);
1831 if (r || options.chroot_directory == NULL ||
1832 strcasecmp(options.chroot_directory, "none") == 0)
1833 fprintf(stderr, "Could not chdir to home "
1834 "directory %s: %s\n", pw->pw_dir,
1840 closefrom(STDERR_FILENO + 1);
1842 if (!options.use_login)
1843 do_rc_files(s, shell);
1845 /* restore SIGPIPE for child */
1846 signal(SIGPIPE, SIG_DFL);
1848 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1849 printf("This service allows sftp connections only.\n");
1852 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1853 extern int optind, optreset;
1857 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1858 args = xstrdup(command ? command : "sftp-server");
1859 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1860 if (i < ARGV_MAX - 1)
1863 optind = optreset = 1;
1864 __progname = argv[0];
1866 ssh_selinux_change_context("sftpd_t");
1868 exit(sftp_server_main(i, argv, s->pw));
1873 if (options.use_login) {
1874 launch_login(pw, hostname);
1878 /* Get the last component of the shell name. */
1879 if ((shell0 = strrchr(shell, '/')) != NULL)
1885 * If we have no command, execute the shell. In this case, the shell
1886 * name to be passed in argv[0] is preceded by '-' to indicate that
1887 * this is a login shell.
1892 /* Start the shell. Set initial character to '-'. */
1895 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1896 >= sizeof(argv0) - 1) {
1902 /* Execute the shell. */
1905 execve(shell, argv, env);
1907 /* Executing the shell failed. */
1912 * Execute the command using the user's shell. This uses the -c
1913 * option to execute the command.
1915 argv[0] = (char *) shell0;
1917 argv[2] = (char *) command;
1919 execve(shell, argv, env);
1925 session_unused(int id)
1927 debug3("%s: session id %d unused", __func__, id);
1928 if (id >= options.max_sessions ||
1929 id >= sessions_nalloc) {
1930 fatal("%s: insane session id %d (max %d nalloc %d)",
1931 __func__, id, options.max_sessions, sessions_nalloc);
1933 memset(&sessions[id], 0, sizeof(*sessions));
1934 sessions[id].self = id;
1935 sessions[id].used = 0;
1936 sessions[id].chanid = -1;
1937 sessions[id].ptyfd = -1;
1938 sessions[id].ttyfd = -1;
1939 sessions[id].ptymaster = -1;
1940 sessions[id].x11_chanids = NULL;
1941 sessions[id].next_unused = sessions_first_unused;
1942 sessions_first_unused = id;
1950 if (sessions_first_unused == -1) {
1951 if (sessions_nalloc >= options.max_sessions)
1953 debug2("%s: allocate (allocated %d max %d)",
1954 __func__, sessions_nalloc, options.max_sessions);
1955 tmp = xrealloc(sessions, sessions_nalloc + 1,
1958 error("%s: cannot allocate %d sessions",
1959 __func__, sessions_nalloc + 1);
1963 session_unused(sessions_nalloc++);
1966 if (sessions_first_unused >= sessions_nalloc ||
1967 sessions_first_unused < 0) {
1968 fatal("%s: insane first_unused %d max %d nalloc %d",
1969 __func__, sessions_first_unused, options.max_sessions,
1973 s = &sessions[sessions_first_unused];
1975 fatal("%s: session %d already used",
1976 __func__, sessions_first_unused);
1978 sessions_first_unused = s->next_unused;
1980 s->next_unused = -1;
1981 debug("session_new: session %d", s->self);
1990 for (i = 0; i < sessions_nalloc; i++) {
1991 Session *s = &sessions[i];
1993 debug("dump: used %d next_unused %d session %d %p "
1994 "channel %d pid %ld",
2005 session_open(Authctxt *authctxt, int chanid)
2007 Session *s = session_new();
2008 debug("session_open: channel %d", chanid);
2010 error("no more sessions");
2013 s->authctxt = authctxt;
2014 s->pw = authctxt->pw;
2015 if (s->pw == NULL || !authctxt->valid)
2016 fatal("no user for session %d", s->self);
2017 debug("session_open: session %d: link with channel %d", s->self, chanid);
2023 session_by_tty(char *tty)
2026 for (i = 0; i < sessions_nalloc; i++) {
2027 Session *s = &sessions[i];
2028 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2029 debug("session_by_tty: session %d tty %s", i, tty);
2033 debug("session_by_tty: unknown tty %.100s", tty);
2039 session_by_channel(int id)
2042 for (i = 0; i < sessions_nalloc; i++) {
2043 Session *s = &sessions[i];
2044 if (s->used && s->chanid == id) {
2045 debug("session_by_channel: session %d channel %d",
2050 debug("session_by_channel: unknown channel %d", id);
2056 session_by_x11_channel(int id)
2060 for (i = 0; i < sessions_nalloc; i++) {
2061 Session *s = &sessions[i];
2063 if (s->x11_chanids == NULL || !s->used)
2065 for (j = 0; s->x11_chanids[j] != -1; j++) {
2066 if (s->x11_chanids[j] == id) {
2067 debug("session_by_x11_channel: session %d "
2068 "channel %d", s->self, id);
2073 debug("session_by_x11_channel: unknown channel %d", id);
2079 session_by_pid(pid_t pid)
2082 debug("session_by_pid: pid %ld", (long)pid);
2083 for (i = 0; i < sessions_nalloc; i++) {
2084 Session *s = &sessions[i];
2085 if (s->used && s->pid == pid)
2088 error("session_by_pid: unknown pid %ld", (long)pid);
2094 session_window_change_req(Session *s)
2096 s->col = packet_get_int();
2097 s->row = packet_get_int();
2098 s->xpixel = packet_get_int();
2099 s->ypixel = packet_get_int();
2101 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2106 session_pty_req(Session *s)
2111 if (no_pty_flag || !options.permit_tty) {
2112 debug("Allocating a pty not permitted for this authentication.");
2115 if (s->ttyfd != -1) {
2116 packet_disconnect("Protocol error: you already have a pty.");
2120 s->term = packet_get_string(&len);
2123 s->col = packet_get_int();
2124 s->row = packet_get_int();
2126 s->row = packet_get_int();
2127 s->col = packet_get_int();
2129 s->xpixel = packet_get_int();
2130 s->ypixel = packet_get_int();
2132 if (strcmp(s->term, "") == 0) {
2137 /* Allocate a pty and open it. */
2138 debug("Allocating pty.");
2139 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2145 error("session_pty_req: session %d alloc failed", s->self);
2148 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2150 /* for SSH1 the tty modes length is not given */
2152 n_bytes = packet_remaining();
2153 tty_parse_modes(s->ttyfd, &n_bytes);
2156 pty_setowner(s->pw, s->tty);
2158 /* Set window size from the packet. */
2159 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2162 session_proctitle(s);
2167 session_subsystem_req(Session *s)
2175 s->subsys = packet_get_string(&len);
2177 debug2("subsystem request for %.100s by user %s", s->subsys,
2180 for (i = 0; i < options.num_subsystems; i++) {
2181 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
2182 prog = options.subsystem_command[i];
2183 cmd = options.subsystem_args[i];
2184 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2185 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2186 debug("subsystem: %s", prog);
2188 if (stat(prog, &st) < 0)
2189 debug("subsystem: cannot stat %s: %s",
2190 prog, strerror(errno));
2191 s->is_subsystem = SUBSYSTEM_EXT;
2192 debug("subsystem: exec() %s", cmd);
2194 success = do_exec(s, cmd) == 0;
2200 logit("subsystem request for %.100s by user %s failed, "
2201 "subsystem not found", s->subsys, s->pw->pw_name);
2207 session_x11_req(Session *s)
2211 if (s->auth_proto != NULL || s->auth_data != NULL) {
2212 error("session_x11_req: session %d: "
2213 "x11 forwarding already active", s->self);
2216 s->single_connection = packet_get_char();
2217 s->auth_proto = packet_get_string(NULL);
2218 s->auth_data = packet_get_string(NULL);
2219 s->screen = packet_get_int();
2222 success = session_setup_x11fwd(s);
2224 free(s->auth_proto);
2226 s->auth_proto = NULL;
2227 s->auth_data = NULL;
2233 session_shell_req(Session *s)
2236 return do_exec(s, NULL) == 0;
2240 session_exec_req(Session *s)
2244 char *command = packet_get_string(&len);
2246 success = do_exec(s, command) == 0;
2252 session_break_req(Session *s)
2255 packet_get_int(); /* ignored */
2258 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2264 session_env_req(Session *s)
2267 u_int name_len, val_len, i;
2269 name = packet_get_cstring(&name_len);
2270 val = packet_get_cstring(&val_len);
2273 /* Don't set too many environment variables */
2274 if (s->num_env > 128) {
2275 debug2("Ignoring env request %s: too many env vars", name);
2279 for (i = 0; i < options.num_accept_env; i++) {
2280 if (match_pattern(name, options.accept_env[i])) {
2281 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2282 s->env = xrealloc(s->env, s->num_env + 1,
2284 s->env[s->num_env].name = name;
2285 s->env[s->num_env].val = val;
2290 debug2("Ignoring env request %s: disallowed name", name);
2299 session_auth_agent_req(Session *s)
2301 static int called = 0;
2303 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2304 debug("session_auth_agent_req: no_agent_forwarding_flag");
2311 return auth_input_request_forwarding(s->pw);
2316 session_input_channel_req(Channel *c, const char *rtype)
2321 if ((s = session_by_channel(c->self)) == NULL) {
2322 logit("session_input_channel_req: no session %d req %.100s",
2326 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2329 * a session is in LARVAL state until a shell, a command
2330 * or a subsystem is executed
2332 if (c->type == SSH_CHANNEL_LARVAL) {
2333 if (strcmp(rtype, "shell") == 0) {
2334 success = session_shell_req(s);
2335 } else if (strcmp(rtype, "exec") == 0) {
2336 success = session_exec_req(s);
2337 } else if (strcmp(rtype, "pty-req") == 0) {
2338 success = session_pty_req(s);
2339 } else if (strcmp(rtype, "x11-req") == 0) {
2340 success = session_x11_req(s);
2341 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2342 success = session_auth_agent_req(s);
2343 } else if (strcmp(rtype, "subsystem") == 0) {
2344 success = session_subsystem_req(s);
2345 } else if (strcmp(rtype, "env") == 0) {
2346 success = session_env_req(s);
2349 if (strcmp(rtype, "window-change") == 0) {
2350 success = session_window_change_req(s);
2351 } else if (strcmp(rtype, "break") == 0) {
2352 success = session_break_req(s);
2359 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2363 fatal("session_set_fds: called for proto != 2.0");
2365 * now that have a child and a pipe to the child,
2366 * we can activate our channel and register the fd's
2368 if (s->chanid == -1)
2369 fatal("no channel for session %d", s->self);
2370 if (options.hpn_disabled)
2371 channel_set_fds(s->chanid,
2373 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2374 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2376 channel_set_fds(s->chanid,
2378 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2379 1, is_tty, options.hpn_buffer_size);
2383 * Function to perform pty cleanup. Also called if we get aborted abnormally
2384 * (e.g., due to a dropped connection).
2387 session_pty_cleanup2(Session *s)
2390 error("session_pty_cleanup: no session");
2396 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2398 /* Record that the user has logged out. */
2400 record_logout(s->pid, s->tty, s->pw->pw_name);
2402 /* Release the pseudo-tty. */
2404 pty_release(s->tty);
2407 * Close the server side of the socket pairs. We must do this after
2408 * the pty cleanup, so that another process doesn't get this pty
2409 * while we're still cleaning up.
2411 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2412 error("close(s->ptymaster/%d): %s",
2413 s->ptymaster, strerror(errno));
2415 /* unlink pty from session */
2420 session_pty_cleanup(Session *s)
2422 PRIVSEP(session_pty_cleanup2(s));
2428 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2443 return "SIG@openssh.com";
2447 session_close_x11(int id)
2451 if ((c = channel_by_id(id)) == NULL) {
2452 debug("session_close_x11: x11 channel %d missing", id);
2454 /* Detach X11 listener */
2455 debug("session_close_x11: detach x11 channel %d", id);
2456 channel_cancel_cleanup(id);
2457 if (c->ostate != CHAN_OUTPUT_CLOSED)
2463 session_close_single_x11(int id, void *arg)
2468 debug3("session_close_single_x11: channel %d", id);
2469 channel_cancel_cleanup(id);
2470 if ((s = session_by_x11_channel(id)) == NULL)
2471 fatal("session_close_single_x11: no x11 channel %d", id);
2472 for (i = 0; s->x11_chanids[i] != -1; i++) {
2473 debug("session_close_single_x11: session %d: "
2474 "closing channel %d", s->self, s->x11_chanids[i]);
2476 * The channel "id" is already closing, but make sure we
2477 * close all of its siblings.
2479 if (s->x11_chanids[i] != id)
2480 session_close_x11(s->x11_chanids[i]);
2482 free(s->x11_chanids);
2483 s->x11_chanids = NULL;
2486 free(s->auth_proto);
2487 s->auth_proto = NULL;
2489 s->auth_data = NULL;
2490 free(s->auth_display);
2491 s->auth_display = NULL;
2495 session_exit_message(Session *s, int status)
2499 if ((c = channel_lookup(s->chanid)) == NULL)
2500 fatal("session_exit_message: session %d: no channel %d",
2501 s->self, s->chanid);
2502 debug("session_exit_message: session %d channel %d pid %ld",
2503 s->self, s->chanid, (long)s->pid);
2505 if (WIFEXITED(status)) {
2506 channel_request_start(s->chanid, "exit-status", 0);
2507 packet_put_int(WEXITSTATUS(status));
2509 } else if (WIFSIGNALED(status)) {
2510 channel_request_start(s->chanid, "exit-signal", 0);
2511 packet_put_cstring(sig2name(WTERMSIG(status)));
2513 packet_put_char(WCOREDUMP(status)? 1 : 0);
2514 #else /* WCOREDUMP */
2516 #endif /* WCOREDUMP */
2517 packet_put_cstring("");
2518 packet_put_cstring("");
2521 /* Some weird exit cause. Just exit. */
2522 packet_disconnect("wait returned status %04x.", status);
2525 /* disconnect channel */
2526 debug("session_exit_message: release channel %d", s->chanid);
2529 * Adjust cleanup callback attachment to send close messages when
2530 * the channel gets EOF. The session will be then be closed
2531 * by session_close_by_channel when the childs close their fds.
2533 channel_register_cleanup(c->self, session_close_by_channel, 1);
2536 * emulate a write failure with 'chan_write_failed', nobody will be
2537 * interested in data we write.
2538 * Note that we must not call 'chan_read_failed', since there could
2539 * be some more data waiting in the pipe.
2541 if (c->ostate != CHAN_OUTPUT_CLOSED)
2542 chan_write_failed(c);
2546 session_close(Session *s)
2550 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2552 session_pty_cleanup(s);
2555 free(s->x11_chanids);
2556 free(s->auth_display);
2558 free(s->auth_proto);
2560 if (s->env != NULL) {
2561 for (i = 0; i < s->num_env; i++) {
2562 free(s->env[i].name);
2563 free(s->env[i].val);
2567 session_proctitle(s);
2568 session_unused(s->self);
2572 session_close_by_pid(pid_t pid, int status)
2574 Session *s = session_by_pid(pid);
2576 debug("session_close_by_pid: no session for pid %ld",
2580 if (s->chanid != -1)
2581 session_exit_message(s, status);
2583 session_pty_cleanup(s);
2588 * this is called when a channel dies before
2589 * the session 'child' itself dies
2592 session_close_by_channel(int id, void *arg)
2594 Session *s = session_by_channel(id);
2598 debug("session_close_by_channel: no session for id %d", id);
2601 debug("session_close_by_channel: channel %d child %ld",
2604 debug("session_close_by_channel: channel %d: has child", id);
2606 * delay detach of session, but release pty, since
2607 * the fd's to the child are already closed
2610 session_pty_cleanup(s);
2613 /* detach by removing callback */
2614 channel_cancel_cleanup(s->chanid);
2616 /* Close any X11 listeners associated with this session */
2617 if (s->x11_chanids != NULL) {
2618 for (i = 0; s->x11_chanids[i] != -1; i++) {
2619 session_close_x11(s->x11_chanids[i]);
2620 s->x11_chanids[i] = -1;
2629 session_destroy_all(void (*closefunc)(Session *))
2632 for (i = 0; i < sessions_nalloc; i++) {
2633 Session *s = &sessions[i];
2635 if (closefunc != NULL)
2644 session_tty_list(void)
2646 static char buf[1024];
2651 for (i = 0; i < sessions_nalloc; i++) {
2652 Session *s = &sessions[i];
2653 if (s->used && s->ttyfd != -1) {
2655 if (strncmp(s->tty, "/dev/", 5) != 0) {
2656 cp = strrchr(s->tty, '/');
2657 cp = (cp == NULL) ? s->tty : cp + 1;
2662 strlcat(buf, ",", sizeof buf);
2663 strlcat(buf, cp, sizeof buf);
2667 strlcpy(buf, "notty", sizeof buf);
2672 session_proctitle(Session *s)
2675 error("no user for session %d", s->self);
2677 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2681 session_setup_x11fwd(Session *s)
2684 char display[512], auth_display[512];
2685 char hostname[NI_MAXHOST];
2688 if (no_x11_forwarding_flag) {
2689 packet_send_debug("X11 forwarding disabled in user configuration file.");
2692 if (!options.x11_forwarding) {
2693 debug("X11 forwarding disabled in server configuration file.");
2696 if (!options.xauth_location ||
2697 (stat(options.xauth_location, &st) == -1)) {
2698 packet_send_debug("No xauth program; cannot forward with spoofing.");
2701 if (options.use_login) {
2702 packet_send_debug("X11 forwarding disabled; "
2703 "not compatible with UseLogin=yes.");
2706 if (s->display != NULL) {
2707 debug("X11 display already set.");
2710 if (x11_create_display_inet(options.x11_display_offset,
2711 options.x11_use_localhost, s->single_connection,
2712 &s->display_number, &s->x11_chanids) == -1) {
2713 debug("x11_create_display_inet failed.");
2716 for (i = 0; s->x11_chanids[i] != -1; i++) {
2717 channel_register_cleanup(s->x11_chanids[i],
2718 session_close_single_x11, 0);
2721 /* Set up a suitable value for the DISPLAY variable. */
2722 if (gethostname(hostname, sizeof(hostname)) < 0)
2723 fatal("gethostname: %.100s", strerror(errno));
2725 * auth_display must be used as the displayname when the
2726 * authorization entry is added with xauth(1). This will be
2727 * different than the DISPLAY string for localhost displays.
2729 if (options.x11_use_localhost) {
2730 snprintf(display, sizeof display, "localhost:%u.%u",
2731 s->display_number, s->screen);
2732 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2733 s->display_number, s->screen);
2734 s->display = xstrdup(display);
2735 s->auth_display = xstrdup(auth_display);
2737 #ifdef IPADDR_IN_DISPLAY
2739 struct in_addr my_addr;
2741 he = gethostbyname(hostname);
2743 error("Can't get IP address for X11 DISPLAY.");
2744 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2747 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2748 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2749 s->display_number, s->screen);
2751 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2752 s->display_number, s->screen);
2754 s->display = xstrdup(display);
2755 s->auth_display = xstrdup(display);
2762 do_authenticated2(Authctxt *authctxt)
2764 server_loop2(authctxt);
2768 do_cleanup(Authctxt *authctxt)
2770 static int called = 0;
2772 debug("do_cleanup");
2774 /* no cleanup if we're in the child for login shell */
2778 /* avoid double cleanup */
2783 if (authctxt == NULL)
2787 if (options.use_pam) {
2789 sshpam_thread_cleanup();
2793 if (!authctxt->authenticated)
2797 if (options.kerberos_ticket_cleanup &&
2799 krb5_cleanup_proc(authctxt);
2803 if (compat20 && options.gss_cleanup_creds)
2804 ssh_gssapi_cleanup_creds();
2807 /* remove agent socket */
2808 auth_sock_cleanup_proc(authctxt->pw);
2811 * Cleanup ptys/utmp only if privsep is disabled,
2812 * or if running in monitor.
2814 if (!use_privsep || mm_is_monitor())
2815 session_destroy_all(session_pty_cleanup2);