1 /* $OpenBSD: session.c,v 1.252 2010/03/07 11:57:13 dtucker 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.
39 #include <sys/types.h>
40 #include <sys/param.h>
41 #ifdef HAVE_SYS_STAT_H
42 # include <sys/stat.h>
44 #include <sys/socket.h>
48 #include <arpa/inet.h>
63 #include "openbsd-compat/sys-queue.h"
82 #include "auth-options.h"
83 #include "pathnames.h"
87 #include "serverloop.h"
92 #include "monitor_wrap.h"
95 #if defined(KRB5) && defined(USE_AFS)
99 #define IS_INTERNAL_SFTP(c) \
100 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
101 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
102 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
103 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
107 Session *session_new(void);
108 void session_set_fds(Session *, int, int, int, int);
109 void session_pty_cleanup(Session *);
110 void session_proctitle(Session *);
111 int session_setup_x11fwd(Session *);
112 int do_exec_pty(Session *, const char *);
113 int do_exec_no_pty(Session *, const char *);
114 int do_exec(Session *, const char *);
115 void do_login(Session *, const char *);
116 #ifdef LOGIN_NEEDS_UTMPX
117 static void do_pre_login(Session *s);
119 void do_child(Session *, const char *);
121 int check_quietlogin(Session *, const char *);
123 static void do_authenticated1(Authctxt *);
124 static void do_authenticated2(Authctxt *);
126 static int session_pty_req(Session *);
129 extern ServerOptions options;
130 extern char *__progname;
131 extern int log_stderr;
132 extern int debug_flag;
133 extern u_int utmp_len;
134 extern int startup_pipe;
135 extern void destroy_sensitive_data(void);
136 extern Buffer loginmsg;
138 /* original command from peer. */
139 const char *original_command = NULL;
142 static int sessions_first_unused = -1;
143 static int sessions_nalloc = 0;
144 static Session *sessions = NULL;
146 #define SUBSYSTEM_NONE 0
147 #define SUBSYSTEM_EXT 1
148 #define SUBSYSTEM_INT_SFTP 2
149 #define SUBSYSTEM_INT_SFTP_ERROR 3
151 #ifdef HAVE_LOGIN_CAP
155 static int is_child = 0;
157 /* Name and directory of socket for authentication agent forwarding. */
158 static char *auth_sock_name = NULL;
159 static char *auth_sock_dir = NULL;
161 /* removes the agent forwarding socket */
164 auth_sock_cleanup_proc(struct passwd *pw)
166 if (auth_sock_name != NULL) {
167 temporarily_use_uid(pw);
168 unlink(auth_sock_name);
169 rmdir(auth_sock_dir);
170 auth_sock_name = NULL;
176 auth_input_request_forwarding(struct passwd * pw)
180 struct sockaddr_un sunaddr;
182 if (auth_sock_name != NULL) {
183 error("authentication forwarding requested twice.");
187 /* Temporarily drop privileged uid for mkdir/bind. */
188 temporarily_use_uid(pw);
190 /* Allocate a buffer for the socket name, and format the name. */
191 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
193 /* Create private directory for socket */
194 if (mkdtemp(auth_sock_dir) == NULL) {
195 packet_send_debug("Agent forwarding disabled: "
196 "mkdtemp() failed: %.100s", strerror(errno));
198 xfree(auth_sock_dir);
199 auth_sock_dir = NULL;
203 xasprintf(&auth_sock_name, "%s/agent.%ld",
204 auth_sock_dir, (long) getpid());
206 /* Create the socket. */
207 sock = socket(AF_UNIX, SOCK_STREAM, 0);
209 error("socket: %.100s", strerror(errno));
214 /* Bind it to the name. */
215 memset(&sunaddr, 0, sizeof(sunaddr));
216 sunaddr.sun_family = AF_UNIX;
217 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
219 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
220 error("bind: %.100s", strerror(errno));
225 /* Restore the privileged uid. */
228 /* Start listening on the socket. */
229 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
230 error("listen: %.100s", strerror(errno));
234 /* Allocate a channel for the authentication agent socket. */
235 nc = channel_new("auth socket",
236 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
237 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
238 0, "auth socket", 1);
239 nc->path = xstrdup(auth_sock_name);
243 if (auth_sock_name != NULL)
244 xfree(auth_sock_name);
245 if (auth_sock_dir != NULL) {
246 rmdir(auth_sock_dir);
247 xfree(auth_sock_dir);
251 auth_sock_name = NULL;
252 auth_sock_dir = NULL;
257 display_loginmsg(void)
259 if (buffer_len(&loginmsg) > 0) {
260 buffer_append(&loginmsg, "\0", 1);
261 printf("%s", (char *)buffer_ptr(&loginmsg));
262 buffer_clear(&loginmsg);
267 do_authenticated(Authctxt *authctxt)
269 setproctitle("%s", authctxt->pw->pw_name);
271 /* setup the channel layer */
272 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
273 channel_permit_all_opens();
278 do_authenticated2(authctxt);
280 do_authenticated1(authctxt);
282 do_cleanup(authctxt);
286 * Prepares for an interactive session. This is called after the user has
287 * been successfully authenticated. During this message exchange, pseudo
288 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
289 * are requested, etc.
292 do_authenticated1(Authctxt *authctxt)
296 int success, type, screen_flag;
297 int enable_compression_after_reply = 0;
298 u_int proto_len, data_len, dlen, compression_level = 0;
302 error("no more sessions");
305 s->authctxt = authctxt;
306 s->pw = authctxt->pw;
309 * We stay in this loop until the client requests to execute a shell
315 /* Get a packet from the client. */
316 type = packet_read();
318 /* Process the packet. */
320 case SSH_CMSG_REQUEST_COMPRESSION:
321 compression_level = packet_get_int();
323 if (compression_level < 1 || compression_level > 9) {
324 packet_send_debug("Received invalid compression level %d.",
328 if (options.compression == COMP_NONE) {
329 debug2("compression disabled");
332 /* Enable compression after we have responded with SUCCESS. */
333 enable_compression_after_reply = 1;
337 case SSH_CMSG_REQUEST_PTY:
338 success = session_pty_req(s);
341 case SSH_CMSG_X11_REQUEST_FORWARDING:
342 s->auth_proto = packet_get_string(&proto_len);
343 s->auth_data = packet_get_string(&data_len);
345 screen_flag = packet_get_protocol_flags() &
346 SSH_PROTOFLAG_SCREEN_NUMBER;
347 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
349 if (packet_remaining() == 4) {
351 debug2("Buggy client: "
352 "X11 screen flag missing");
353 s->screen = packet_get_int();
358 success = session_setup_x11fwd(s);
360 xfree(s->auth_proto);
362 s->auth_proto = NULL;
367 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
368 if (!options.allow_agent_forwarding ||
369 no_agent_forwarding_flag || compat13) {
370 debug("Authentication agent forwarding not permitted for this authentication.");
373 debug("Received authentication agent forwarding request.");
374 success = auth_input_request_forwarding(s->pw);
377 case SSH_CMSG_PORT_FORWARD_REQUEST:
378 if (no_port_forwarding_flag) {
379 debug("Port forwarding not permitted for this authentication.");
382 if (!options.allow_tcp_forwarding) {
383 debug("Port forwarding not permitted.");
386 debug("Received TCP/IP port forwarding request.");
387 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
388 options.gateway_ports) < 0) {
389 debug("Port forwarding failed.");
395 case SSH_CMSG_MAX_PACKET_SIZE:
396 if (packet_set_maxsize(packet_get_int()) > 0)
400 case SSH_CMSG_EXEC_SHELL:
401 case SSH_CMSG_EXEC_CMD:
402 if (type == SSH_CMSG_EXEC_CMD) {
403 command = packet_get_string(&dlen);
404 debug("Exec command '%.500s'", command);
405 if (do_exec(s, command) != 0)
407 "command execution failed");
410 if (do_exec(s, NULL) != 0)
412 "shell execution failed");
420 * Any unknown messages in this phase are ignored,
421 * and a failure message is returned.
423 logit("Unknown packet type received after authentication: %d", type);
425 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
429 /* Enable compression now that we have replied if appropriate. */
430 if (enable_compression_after_reply) {
431 enable_compression_after_reply = 0;
432 packet_start_compression(compression_level);
439 * This is called to fork and execute a command when we have no tty. This
440 * will call do_child from the child, and server_loop from the parent after
441 * setting up file descriptors and such.
444 do_exec_no_pty(Session *s, const char *command)
449 int pin[2], pout[2], perr[2];
451 /* Allocate pipes for communicating with the program. */
453 error("%s: pipe in: %.100s", __func__, strerror(errno));
456 if (pipe(pout) < 0) {
457 error("%s: pipe out: %.100s", __func__, strerror(errno));
462 if (pipe(perr) < 0) {
463 error("%s: pipe err: %.100s", __func__, strerror(errno));
471 int inout[2], err[2];
473 /* Uses socket pairs to communicate with the program. */
474 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
475 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
478 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
479 error("%s: socketpair #2: %.100s", __func__, strerror(errno));
487 fatal("do_exec_no_pty: no session");
489 session_proctitle(s);
491 /* Fork the child. */
492 switch ((pid = fork())) {
494 error("%s: fork: %.100s", __func__, strerror(errno));
512 /* Child. Reinitialize the log since the pid has changed. */
513 log_init(__progname, options.log_level,
514 options.log_facility, log_stderr);
517 * Create a new session and process group since the 4.4BSD
518 * setlogin() affects the entire process group.
521 error("setsid failed: %.100s", strerror(errno));
525 * Redirect stdin. We close the parent side of the socket
526 * pair, and make the child side the standard input.
529 if (dup2(pin[0], 0) < 0)
530 perror("dup2 stdin");
533 /* Redirect stdout. */
535 if (dup2(pout[1], 1) < 0)
536 perror("dup2 stdout");
539 /* Redirect stderr. */
541 if (dup2(perr[1], 2) < 0)
542 perror("dup2 stderr");
546 * Redirect stdin, stdout, and stderr. Stdin and stdout will
547 * use the same socket, as some programs (particularly rdist)
548 * seem to depend on it.
552 if (dup2(inout[0], 0) < 0) /* stdin */
553 perror("dup2 stdin");
554 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
555 perror("dup2 stdout");
557 if (dup2(err[0], 2) < 0) /* stderr */
558 perror("dup2 stderr");
564 cray_init_job(s->pw); /* set up cray jid and tmpdir */
567 /* Do processing for the child (exec command etc). */
568 do_child(s, command);
575 signal(WJSIGNAL, cray_job_termination_handler);
578 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
582 /* Set interactive/non-interactive mode. */
583 packet_set_interactive(s->display != NULL);
586 * Clear loginmsg, since it's the child's responsibility to display
587 * it to the user, otherwise multiple sessions may accumulate
588 * multiple copies of the login messages.
590 buffer_clear(&loginmsg);
593 /* We are the parent. Close the child sides of the pipes. */
599 if (s->is_subsystem) {
603 session_set_fds(s, pin[1], pout[0], perr[0], 0);
605 /* Enter the interactive session. */
606 server_loop(pid, pin[1], pout[0], perr[0]);
607 /* server_loop has closed pin[1], pout[0], and perr[0]. */
610 /* We are the parent. Close the child sides of the socket pairs. */
615 * Enter the interactive session. Note: server_loop must be able to
616 * handle the case that fdin and fdout are the same.
619 session_set_fds(s, inout[1], inout[1],
620 s->is_subsystem ? -1 : err[1], 0);
624 server_loop(pid, inout[1], inout[1], err[1]);
625 /* server_loop has closed inout[1] and err[1]. */
632 * This is called to fork and execute a command when we have a tty. This
633 * will call do_child from the child, and server_loop from the parent after
634 * setting up file descriptors, controlling tty, updating wtmp, utmp,
635 * lastlog, and other such operations.
638 do_exec_pty(Session *s, const char *command)
640 int fdout, ptyfd, ttyfd, ptymaster;
644 fatal("do_exec_pty: no session");
649 * Create another descriptor of the pty master side for use as the
650 * standard input. We could use the original descriptor, but this
651 * simplifies code in server_loop. The descriptor is bidirectional.
652 * Do this before forking (and cleanup in the child) so as to
653 * detect and gracefully fail out-of-fd conditions.
655 if ((fdout = dup(ptyfd)) < 0) {
656 error("%s: dup #1: %s", __func__, strerror(errno));
661 /* we keep a reference to the pty master */
662 if ((ptymaster = dup(ptyfd)) < 0) {
663 error("%s: dup #2: %s", __func__, strerror(errno));
670 /* Fork the child. */
671 switch ((pid = fork())) {
673 error("%s: fork: %.100s", __func__, strerror(errno));
685 /* Child. Reinitialize the log because the pid has changed. */
686 log_init(__progname, options.log_level,
687 options.log_facility, log_stderr);
688 /* Close the master side of the pseudo tty. */
691 /* Make the pseudo tty our controlling tty. */
692 pty_make_controlling_tty(&ttyfd, s->tty);
694 /* Redirect stdin/stdout/stderr from the pseudo tty. */
695 if (dup2(ttyfd, 0) < 0)
696 error("dup2 stdin: %s", strerror(errno));
697 if (dup2(ttyfd, 1) < 0)
698 error("dup2 stdout: %s", strerror(errno));
699 if (dup2(ttyfd, 2) < 0)
700 error("dup2 stderr: %s", strerror(errno));
702 /* Close the extra descriptor for the pseudo tty. */
705 /* record login, etc. similar to login(1) */
707 if (!(options.use_login && command == NULL)) {
709 cray_init_job(s->pw); /* set up cray jid and tmpdir */
711 do_login(s, command);
713 # ifdef LOGIN_NEEDS_UTMPX
719 * Do common processing for the child, such as execing
722 do_child(s, command);
729 signal(WJSIGNAL, cray_job_termination_handler);
732 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
737 /* Parent. Close the slave side of the pseudo tty. */
740 /* Enter interactive session. */
741 s->ptymaster = ptymaster;
742 packet_set_interactive(1);
744 session_set_fds(s, ptyfd, fdout, -1, 1);
746 server_loop(pid, ptyfd, fdout, -1);
747 /* server_loop _has_ closed ptyfd and fdout. */
752 #ifdef LOGIN_NEEDS_UTMPX
754 do_pre_login(Session *s)
757 struct sockaddr_storage from;
758 pid_t pid = getpid();
761 * Get IP address of client. If the connection is not a socket, let
762 * the address be 0.0.0.0.
764 memset(&from, 0, sizeof(from));
765 fromlen = sizeof(from);
766 if (packet_connection_is_on_socket()) {
767 if (getpeername(packet_get_connection_in(),
768 (struct sockaddr *)&from, &fromlen) < 0) {
769 debug("getpeername: %.100s", strerror(errno));
774 record_utmp_only(pid, s->tty, s->pw->pw_name,
775 get_remote_name_or_ip(utmp_len, options.use_dns),
776 (struct sockaddr *)&from, fromlen);
781 * This is called to fork and execute a command. If another command is
782 * to be forced, execute that instead.
785 do_exec(Session *s, const char *command)
789 if (options.adm_forced_command) {
790 original_command = command;
791 command = options.adm_forced_command;
792 if (IS_INTERNAL_SFTP(command)) {
793 s->is_subsystem = s->is_subsystem ?
794 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
795 } else if (s->is_subsystem)
796 s->is_subsystem = SUBSYSTEM_EXT;
797 debug("Forced command (config) '%.900s'", command);
798 } else if (forced_command) {
799 original_command = command;
800 command = forced_command;
801 if (IS_INTERNAL_SFTP(command)) {
802 s->is_subsystem = s->is_subsystem ?
803 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
804 } else if (s->is_subsystem)
805 s->is_subsystem = SUBSYSTEM_EXT;
806 debug("Forced command (key option) '%.900s'", command);
809 #ifdef SSH_AUDIT_EVENTS
811 PRIVSEP(audit_run_command(command));
812 else if (s->ttyfd == -1) {
813 char *shell = s->pw->pw_shell;
815 if (shell[0] == '\0') /* empty shell means /bin/sh */
817 PRIVSEP(audit_run_command(shell));
821 ret = do_exec_pty(s, command);
823 ret = do_exec_no_pty(s, command);
825 original_command = NULL;
828 * Clear loginmsg: it's the child's responsibility to display
829 * it to the user, otherwise multiple sessions may accumulate
830 * multiple copies of the login messages.
832 buffer_clear(&loginmsg);
837 /* administrative, login(1)-like work */
839 do_login(Session *s, const char *command)
842 struct sockaddr_storage from;
843 struct passwd * pw = s->pw;
844 pid_t pid = getpid();
847 * Get IP address of client. If the connection is not a socket, let
848 * the address be 0.0.0.0.
850 memset(&from, 0, sizeof(from));
851 fromlen = sizeof(from);
852 if (packet_connection_is_on_socket()) {
853 if (getpeername(packet_get_connection_in(),
854 (struct sockaddr *)&from, &fromlen) < 0) {
855 debug("getpeername: %.100s", strerror(errno));
860 /* Record that there was a login on that tty from the remote host. */
862 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
863 get_remote_name_or_ip(utmp_len,
865 (struct sockaddr *)&from, fromlen);
869 * If password change is needed, do it now.
870 * This needs to occur before the ~/.hushlogin check.
872 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
875 s->authctxt->force_pwchange = 0;
876 /* XXX - signal [net] parent to enable forwardings */
880 if (check_quietlogin(s, command))
889 * Display the message of the day.
896 #ifdef HAVE_LOGIN_CAP
900 #ifdef HAVE_LOGIN_CAP
901 fname = login_getcapstr(lc, "copyright", NULL, NULL);
902 if (fname != NULL && (f = fopen(fname, "r")) != NULL) {
903 while (fgets(buf, sizeof(buf), f) != NULL)
907 #endif /* HAVE_LOGIN_CAP */
908 (void)printf("%s\n\t%s %s\n",
909 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
910 "The Regents of the University of California. ",
911 "All rights reserved.");
915 if (options.print_motd) {
916 #ifdef HAVE_LOGIN_CAP
917 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
920 f = fopen("/etc/motd", "r");
923 while (fgets(buf, sizeof(buf), f))
932 * Check for quiet login, either .hushlogin or command given.
935 check_quietlogin(Session *s, const char *command)
938 struct passwd *pw = s->pw;
941 /* Return 1 if .hushlogin exists or a command given. */
944 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
945 #ifdef HAVE_LOGIN_CAP
946 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
949 if (stat(buf, &st) >= 0)
956 * Sets the value of the given variable in the environment. If the variable
957 * already exists, its value is overridden.
960 child_set_env(char ***envp, u_int *envsizep, const char *name,
968 * If we're passed an uninitialized list, allocate a single null
969 * entry before continuing.
971 if (*envp == NULL && *envsizep == 0) {
972 *envp = xmalloc(sizeof(char *));
978 * Find the slot where the value should be stored. If the variable
979 * already exists, we reuse the slot; otherwise we append a new slot
980 * at the end of the array, expanding if necessary.
983 namelen = strlen(name);
984 for (i = 0; env[i]; i++)
985 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
988 /* Reuse the slot. */
991 /* New variable. Expand if necessary. */
993 if (i >= envsize - 1) {
995 fatal("child_set_env: too many env vars");
997 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1000 /* Need to set the NULL pointer at end of array beyond the new slot. */
1004 /* Allocate space and format the variable in the appropriate slot. */
1005 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1006 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1010 * Reads environment variables from the given file and adds/overrides them
1011 * into the environment. If the file does not exist, this does nothing.
1012 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1013 * and assignments of the form name=value. No other forms are allowed.
1016 read_environment_file(char ***env, u_int *envsize,
1017 const char *filename)
1024 f = fopen(filename, "r");
1028 while (fgets(buf, sizeof(buf), f)) {
1029 if (++lineno > 1000)
1030 fatal("Too many lines in environment file %s", filename);
1031 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1033 if (!*cp || *cp == '#' || *cp == '\n')
1036 cp[strcspn(cp, "\n")] = '\0';
1038 value = strchr(cp, '=');
1039 if (value == NULL) {
1040 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1045 * Replace the equals sign by nul, and advance value to
1050 child_set_env(env, envsize, cp, value);
1055 #ifdef HAVE_ETC_DEFAULT_LOGIN
1057 * Return named variable from specified environment, or NULL if not present.
1060 child_get_env(char **env, const char *name)
1066 for (i=0; env[i] != NULL; i++)
1067 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1068 return(env[i] + len + 1);
1073 * Read /etc/default/login.
1074 * We pick up the PATH (or SUPATH for root) and UMASK.
1077 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1079 char **tmpenv = NULL, *var;
1080 u_int i, tmpenvsize = 0;
1084 * We don't want to copy the whole file to the child's environment,
1085 * so we use a temporary environment and copy the variables we're
1088 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1094 var = child_get_env(tmpenv, "SUPATH");
1096 var = child_get_env(tmpenv, "PATH");
1098 child_set_env(env, envsize, "PATH", var);
1100 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1101 if (sscanf(var, "%5lo", &mask) == 1)
1102 umask((mode_t)mask);
1104 for (i = 0; tmpenv[i] != NULL; i++)
1108 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1111 copy_environment(char **source, char ***env, u_int *envsize)
1113 char *var_name, *var_val;
1119 for(i = 0; source[i] != NULL; i++) {
1120 var_name = xstrdup(source[i]);
1121 if ((var_val = strstr(var_name, "=")) == NULL) {
1127 debug3("Copy environment: %s=%s", var_name, var_val);
1128 child_set_env(env, envsize, var_name, var_val);
1135 do_setup_env(Session *s, const char *shell)
1140 struct passwd *pw = s->pw;
1141 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1144 extern char **environ;
1148 /* Initialize the environment. */
1150 env = xcalloc(envsize, sizeof(char *));
1155 * The Windows environment contains some setting which are
1156 * important for a running system. They must not be dropped.
1161 p = fetch_windows_environment();
1162 copy_environment(p, &env, &envsize);
1163 free_windows_environment(p);
1168 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1171 /* Allow any GSSAPI methods that we've used to alter
1172 * the childs environment as they see fit
1174 ssh_gssapi_do_child(&env, &envsize);
1177 if (!options.use_login) {
1178 /* Set basic environment. */
1179 for (i = 0; i < s->num_env; i++)
1180 child_set_env(&env, &envsize, s->env[i].name,
1183 child_set_env(&env, &envsize, "USER", pw->pw_name);
1184 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1186 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1188 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1189 snprintf(buf, sizeof buf, "%.200s/%.50s",
1190 _PATH_MAILDIR, pw->pw_name);
1191 child_set_env(&env, &envsize, "MAIL", buf);
1192 #ifdef HAVE_LOGIN_CAP
1193 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1194 child_set_env(&env, &envsize, "TERM", "su");
1196 environ = xmalloc(sizeof(char *));
1198 (void) setusercontext(lc, pw, pw->pw_uid,
1199 LOGIN_SETENV|LOGIN_SETPATH);
1200 copy_environment(environ, &env, &envsize);
1201 for (var = environ; *var != NULL; ++var)
1205 #else /* HAVE_LOGIN_CAP */
1206 # ifndef HAVE_CYGWIN
1208 * There's no standard path on Windows. The path contains
1209 * important components pointing to the system directories,
1210 * needed for loading shared libraries. So the path better
1211 * remains intact here.
1213 # ifdef HAVE_ETC_DEFAULT_LOGIN
1214 read_etc_default_login(&env, &envsize, pw->pw_uid);
1215 path = child_get_env(env, "PATH");
1216 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1217 if (path == NULL || *path == '\0') {
1218 child_set_env(&env, &envsize, "PATH",
1219 s->pw->pw_uid == 0 ?
1220 SUPERUSER_PATH : _PATH_STDPATH);
1222 # endif /* HAVE_CYGWIN */
1223 #endif /* HAVE_LOGIN_CAP */
1225 /* Normal systems set SHELL by default. */
1226 child_set_env(&env, &envsize, "SHELL", shell);
1229 /* Set custom environment options from RSA authentication. */
1230 if (!options.use_login) {
1231 while (custom_environment) {
1232 struct envstring *ce = custom_environment;
1235 for (i = 0; str[i] != '=' && str[i]; i++)
1237 if (str[i] == '=') {
1239 child_set_env(&env, &envsize, str, str + i + 1);
1241 custom_environment = ce->next;
1247 /* SSH_CLIENT deprecated */
1248 snprintf(buf, sizeof buf, "%.50s %d %d",
1249 get_remote_ipaddr(), get_remote_port(), get_local_port());
1250 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1252 laddr = get_local_ipaddr(packet_get_connection_in());
1253 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1254 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1256 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1259 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1261 child_set_env(&env, &envsize, "TERM", s->term);
1263 child_set_env(&env, &envsize, "DISPLAY", s->display);
1264 if (original_command)
1265 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1269 if (cray_tmpdir[0] != '\0')
1270 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1271 #endif /* _UNICOS */
1274 * Since we clear KRB5CCNAME at startup, if it's set now then it
1275 * must have been set by a native authentication method (eg AIX or
1276 * SIA), so copy it to the child.
1281 if ((cp = getenv("KRB5CCNAME")) != NULL)
1282 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1289 if ((cp = getenv("AUTHSTATE")) != NULL)
1290 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1291 read_environment_file(&env, &envsize, "/etc/environment");
1295 if (s->authctxt->krb5_ccname)
1296 child_set_env(&env, &envsize, "KRB5CCNAME",
1297 s->authctxt->krb5_ccname);
1301 * Pull in any environment variables that may have
1304 if (options.use_pam) {
1307 p = fetch_pam_child_environment();
1308 copy_environment(p, &env, &envsize);
1309 free_pam_environment(p);
1311 p = fetch_pam_environment();
1312 copy_environment(p, &env, &envsize);
1313 free_pam_environment(p);
1315 #endif /* USE_PAM */
1317 if (auth_sock_name != NULL)
1318 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1321 /* read $HOME/.ssh/environment. */
1322 if (options.permit_user_env && !options.use_login) {
1323 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1324 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1325 read_environment_file(&env, &envsize, buf);
1328 /* dump the environment */
1329 fprintf(stderr, "Environment:\n");
1330 for (i = 0; env[i]; i++)
1331 fprintf(stderr, " %.200s\n", env[i]);
1337 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1338 * first in this order).
1341 do_rc_files(Session *s, const char *shell)
1349 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1351 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1352 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1353 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1354 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1355 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1357 fprintf(stderr, "Running %s\n", cmd);
1358 f = popen(cmd, "w");
1361 fprintf(f, "%s %s\n", s->auth_proto,
1365 fprintf(stderr, "Could not run %s\n",
1367 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1369 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1370 _PATH_SSH_SYSTEM_RC);
1371 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1374 fprintf(f, "%s %s\n", s->auth_proto,
1378 fprintf(stderr, "Could not run %s\n",
1379 _PATH_SSH_SYSTEM_RC);
1380 } else if (do_xauth && options.xauth_location != NULL) {
1381 /* Add authority data to .Xauthority if appropriate. */
1384 "Running %.500s remove %.100s\n",
1385 options.xauth_location, s->auth_display);
1387 "%.500s add %.100s %.100s %.100s\n",
1388 options.xauth_location, s->auth_display,
1389 s->auth_proto, s->auth_data);
1391 snprintf(cmd, sizeof cmd, "%s -q -",
1392 options.xauth_location);
1393 f = popen(cmd, "w");
1395 fprintf(f, "remove %s\n",
1397 fprintf(f, "add %s %s %s\n",
1398 s->auth_display, s->auth_proto,
1402 fprintf(stderr, "Could not run %s\n",
1409 do_nologin(struct passwd *pw)
1412 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1415 #ifdef HAVE_LOGIN_CAP
1416 if (login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1418 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1420 if (pw->pw_uid == 0)
1424 if (stat(nl, &sb) == -1) {
1430 /* /etc/nologin exists. Print its contents if we can and exit. */
1431 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1432 if ((f = fopen(nl, "r")) != NULL) {
1433 while (fgets(buf, sizeof(buf), f))
1441 * Chroot into a directory after checking it for safety: all path components
1442 * must be root-owned directories with strict permissions.
1445 safely_chroot(const char *path, uid_t uid)
1448 char component[MAXPATHLEN];
1452 fatal("chroot path does not begin at root");
1453 if (strlen(path) >= sizeof(component))
1454 fatal("chroot path too long");
1457 * Descend the path, checking that each component is a
1458 * root-owned directory with strict permissions.
1460 for (cp = path; cp != NULL;) {
1461 if ((cp = strchr(cp, '/')) == NULL)
1462 strlcpy(component, path, sizeof(component));
1465 memcpy(component, path, cp - path);
1466 component[cp - path] = '\0';
1469 debug3("%s: checking '%s'", __func__, component);
1471 if (stat(component, &st) != 0)
1472 fatal("%s: stat(\"%s\"): %s", __func__,
1473 component, strerror(errno));
1474 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1475 fatal("bad ownership or modes for chroot "
1476 "directory %s\"%s\"",
1477 cp == NULL ? "" : "component ", component);
1478 if (!S_ISDIR(st.st_mode))
1479 fatal("chroot path %s\"%s\" is not a directory",
1480 cp == NULL ? "" : "component ", component);
1484 if (chdir(path) == -1)
1485 fatal("Unable to chdir to chroot path \"%s\": "
1486 "%s", path, strerror(errno));
1487 if (chroot(path) == -1)
1488 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1489 if (chdir("/") == -1)
1490 fatal("%s: chdir(/) after chroot: %s",
1491 __func__, strerror(errno));
1492 verbose("Changed root directory to \"%s\"", path);
1495 /* Set login name, uid, gid, and groups. */
1497 do_setusercontext(struct passwd *pw)
1499 char *chroot_path, *tmp;
1502 /* Cache selinux status for later use */
1503 (void)ssh_selinux_enabled();
1507 if (getuid() == 0 || geteuid() == 0)
1508 #endif /* HAVE_CYGWIN */
1510 #ifdef HAVE_LOGIN_CAP
1515 if (options.use_pam) {
1516 do_pam_setcred(use_privsep);
1518 # endif /* USE_PAM */
1519 if (setusercontext(lc, pw, pw->pw_uid,
1520 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1521 perror("unable to set user context");
1525 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1526 /* Sets login uid for accounting */
1527 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1528 error("setluid: %s", strerror(errno));
1529 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1531 if (setlogin(pw->pw_name) < 0)
1532 error("setlogin failed: %s", strerror(errno));
1533 if (setgid(pw->pw_gid) < 0) {
1537 /* Initialize the group list. */
1538 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1539 perror("initgroups");
1545 * PAM credentials may take the form of supplementary groups.
1546 * These will have been wiped by the above initgroups() call.
1547 * Reestablish them here.
1549 if (options.use_pam) {
1550 do_pam_setcred(use_privsep);
1552 # endif /* USE_PAM */
1553 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1554 irix_setusercontext(pw);
1555 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1560 if (set_id(pw->pw_name) != 0) {
1563 # endif /* USE_LIBIAF */
1565 #ifdef HAVE_SETPCRED
1567 * If we have a chroot directory, we set all creds except real
1568 * uid which we will need for chroot. If we don't have a
1569 * chroot directory, we don't override anything.
1572 char **creds = NULL, *chroot_creds[] =
1573 { "REAL_USER=root", NULL };
1575 if (options.chroot_directory != NULL &&
1576 strcasecmp(options.chroot_directory, "none") != 0)
1577 creds = chroot_creds;
1579 if (setpcred(pw->pw_name, creds) == -1)
1580 fatal("Failed to set process credentials");
1582 #endif /* HAVE_SETPCRED */
1584 if (options.chroot_directory != NULL &&
1585 strcasecmp(options.chroot_directory, "none") != 0) {
1586 tmp = tilde_expand_filename(options.chroot_directory,
1588 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1589 "u", pw->pw_name, (char *)NULL);
1590 safely_chroot(chroot_path, pw->pw_uid);
1595 #ifdef HAVE_LOGIN_CAP
1596 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1597 perror("unable to set user context (setuser)");
1601 /* Permanently switch to the desired uid. */
1602 permanently_set_uid(pw);
1606 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1607 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1610 ssh_selinux_setup_exec_context(pw->pw_name);
1615 do_pwchange(Session *s)
1618 fprintf(stderr, "WARNING: Your password has expired.\n");
1619 if (s->ttyfd != -1) {
1621 "You must change your password now and login again!\n");
1622 #ifdef PASSWD_NEEDS_USERNAME
1623 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1626 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1631 "Password change required but no TTY available.\n");
1637 launch_login(struct passwd *pw, const char *hostname)
1639 /* Launch login(1). */
1641 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1642 #ifdef xxxLOGIN_NEEDS_TERM
1643 (s->term ? s->term : "unknown"),
1644 #endif /* LOGIN_NEEDS_TERM */
1645 #ifdef LOGIN_NO_ENDOPT
1646 "-p", "-f", pw->pw_name, (char *)NULL);
1648 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1651 /* Login couldn't be executed, die. */
1658 child_close_fds(void)
1662 if (packet_get_connection_in() == packet_get_connection_out())
1663 close(packet_get_connection_in());
1665 close(packet_get_connection_in());
1666 close(packet_get_connection_out());
1669 * Close all descriptors related to channels. They will still remain
1670 * open in the parent.
1672 /* XXX better use close-on-exec? -markus */
1673 channel_close_all();
1676 * Close any extra file descriptors. Note that there may still be
1677 * descriptors left by system functions. They will be closed later.
1682 * Close any extra open file descriptors so that we don't have them
1683 * hanging around in clients. Note that we want to do this after
1684 * initgroups, because at least on Solaris 2.3 it leaves file
1687 for (i = 3; i < 64; i++)
1692 * Performs common processing for the child, such as setting up the
1693 * environment, closing extra file descriptors, setting the user and group
1694 * ids, and executing the command or shell.
1698 do_child(Session *s, const char *command)
1700 extern char **environ;
1702 char *argv[ARGV_MAX];
1703 const char *shell, *shell0, *hostname = NULL;
1704 struct passwd *pw = s->pw;
1707 /* remove hostkey from the child's memory */
1708 destroy_sensitive_data();
1710 /* Force a password change */
1711 if (s->authctxt->force_pwchange) {
1712 do_setusercontext(pw);
1718 /* login(1) is only called if we execute the login shell */
1719 if (options.use_login && command != NULL)
1720 options.use_login = 0;
1723 cray_setup(pw->pw_uid, pw->pw_name, command);
1724 #endif /* _UNICOS */
1727 * Login(1) does this as well, and it needs uid 0 for the "-h"
1728 * switch, so we let login(1) to this for us.
1730 if (!options.use_login) {
1732 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1733 if (!check_quietlogin(s, command))
1735 #else /* HAVE_OSF_SIA */
1736 /* When PAM is enabled we rely on it to do the nologin check */
1737 if (!options.use_pam)
1739 do_setusercontext(pw);
1741 * PAM session modules in do_setusercontext may have
1742 * generated messages, so if this in an interactive
1743 * login then display them too.
1745 if (!check_quietlogin(s, command))
1747 #endif /* HAVE_OSF_SIA */
1751 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1752 debug3("PAM session not opened, exiting");
1759 * Get the shell from the password data. An empty shell field is
1760 * legal, and means /bin/sh.
1762 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1765 * Make sure $SHELL points to the shell from the password file,
1766 * even if shell is overridden from login.conf
1768 env = do_setup_env(s, shell);
1770 #ifdef HAVE_LOGIN_CAP
1771 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1774 /* we have to stash the hostname before we close our socket. */
1775 if (options.use_login)
1776 hostname = get_remote_name_or_ip(utmp_len,
1779 * Close the connection descriptors; note that this is the child, and
1780 * the server will still have the socket open, and it is important
1781 * that we do not shutdown it. Note that the descriptors cannot be
1782 * closed before building the environment, as we call
1783 * get_remote_ipaddr there.
1788 * Must take new environment into use so that .ssh/rc,
1789 * /etc/ssh/sshrc and xauth are run in the proper environment.
1793 #if defined(KRB5) && defined(USE_AFS)
1795 * At this point, we check to see if AFS is active and if we have
1796 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1797 * if we can (and need to) extend the ticket into an AFS token. If
1798 * we don't do this, we run into potential problems if the user's
1799 * home directory is in AFS and it's not world-readable.
1802 if (options.kerberos_get_afs_token && k_hasafs() &&
1803 (s->authctxt->krb5_ctx != NULL)) {
1806 debug("Getting AFS token");
1810 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1811 krb5_afslog(s->authctxt->krb5_ctx,
1812 s->authctxt->krb5_fwd_ccache, cell, NULL);
1814 krb5_afslog_home(s->authctxt->krb5_ctx,
1815 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1819 /* Change current directory to the user's home directory. */
1820 if (chdir(pw->pw_dir) < 0) {
1821 /* Suppress missing homedir warning for chroot case */
1822 #ifdef HAVE_LOGIN_CAP
1823 r = login_getcapbool(lc, "requirehome", 0);
1825 if (r || options.chroot_directory == NULL)
1826 fprintf(stderr, "Could not chdir to home "
1827 "directory %s: %s\n", pw->pw_dir,
1833 closefrom(STDERR_FILENO + 1);
1835 if (!options.use_login)
1836 do_rc_files(s, shell);
1838 /* restore SIGPIPE for child */
1839 signal(SIGPIPE, SIG_DFL);
1841 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1842 printf("This service allows sftp connections only.\n");
1845 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1846 extern int optind, optreset;
1850 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1851 args = xstrdup(command ? command : "sftp-server");
1852 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1853 if (i < ARGV_MAX - 1)
1856 optind = optreset = 1;
1857 __progname = argv[0];
1859 ssh_selinux_change_context("sftpd_t");
1861 exit(sftp_server_main(i, argv, s->pw));
1866 if (options.use_login) {
1867 launch_login(pw, hostname);
1871 /* Get the last component of the shell name. */
1872 if ((shell0 = strrchr(shell, '/')) != NULL)
1878 * If we have no command, execute the shell. In this case, the shell
1879 * name to be passed in argv[0] is preceded by '-' to indicate that
1880 * this is a login shell.
1885 /* Start the shell. Set initial character to '-'. */
1888 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1889 >= sizeof(argv0) - 1) {
1895 /* Execute the shell. */
1898 execve(shell, argv, env);
1900 /* Executing the shell failed. */
1905 * Execute the command using the user's shell. This uses the -c
1906 * option to execute the command.
1908 argv[0] = (char *) shell0;
1910 argv[2] = (char *) command;
1912 execve(shell, argv, env);
1918 session_unused(int id)
1920 debug3("%s: session id %d unused", __func__, id);
1921 if (id >= options.max_sessions ||
1922 id >= sessions_nalloc) {
1923 fatal("%s: insane session id %d (max %d nalloc %d)",
1924 __func__, id, options.max_sessions, sessions_nalloc);
1926 bzero(&sessions[id], sizeof(*sessions));
1927 sessions[id].self = id;
1928 sessions[id].used = 0;
1929 sessions[id].chanid = -1;
1930 sessions[id].ptyfd = -1;
1931 sessions[id].ttyfd = -1;
1932 sessions[id].ptymaster = -1;
1933 sessions[id].x11_chanids = NULL;
1934 sessions[id].next_unused = sessions_first_unused;
1935 sessions_first_unused = id;
1943 if (sessions_first_unused == -1) {
1944 if (sessions_nalloc >= options.max_sessions)
1946 debug2("%s: allocate (allocated %d max %d)",
1947 __func__, sessions_nalloc, options.max_sessions);
1948 tmp = xrealloc(sessions, sessions_nalloc + 1,
1951 error("%s: cannot allocate %d sessions",
1952 __func__, sessions_nalloc + 1);
1956 session_unused(sessions_nalloc++);
1959 if (sessions_first_unused >= sessions_nalloc ||
1960 sessions_first_unused < 0) {
1961 fatal("%s: insane first_unused %d max %d nalloc %d",
1962 __func__, sessions_first_unused, options.max_sessions,
1966 s = &sessions[sessions_first_unused];
1968 fatal("%s: session %d already used",
1969 __func__, sessions_first_unused);
1971 sessions_first_unused = s->next_unused;
1973 s->next_unused = -1;
1974 debug("session_new: session %d", s->self);
1983 for (i = 0; i < sessions_nalloc; i++) {
1984 Session *s = &sessions[i];
1986 debug("dump: used %d next_unused %d session %d %p "
1987 "channel %d pid %ld",
1998 session_open(Authctxt *authctxt, int chanid)
2000 Session *s = session_new();
2001 debug("session_open: channel %d", chanid);
2003 error("no more sessions");
2006 s->authctxt = authctxt;
2007 s->pw = authctxt->pw;
2008 if (s->pw == NULL || !authctxt->valid)
2009 fatal("no user for session %d", s->self);
2010 debug("session_open: session %d: link with channel %d", s->self, chanid);
2016 session_by_tty(char *tty)
2019 for (i = 0; i < sessions_nalloc; i++) {
2020 Session *s = &sessions[i];
2021 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2022 debug("session_by_tty: session %d tty %s", i, tty);
2026 debug("session_by_tty: unknown tty %.100s", tty);
2032 session_by_channel(int id)
2035 for (i = 0; i < sessions_nalloc; i++) {
2036 Session *s = &sessions[i];
2037 if (s->used && s->chanid == id) {
2038 debug("session_by_channel: session %d channel %d",
2043 debug("session_by_channel: unknown channel %d", id);
2049 session_by_x11_channel(int id)
2053 for (i = 0; i < sessions_nalloc; i++) {
2054 Session *s = &sessions[i];
2056 if (s->x11_chanids == NULL || !s->used)
2058 for (j = 0; s->x11_chanids[j] != -1; j++) {
2059 if (s->x11_chanids[j] == id) {
2060 debug("session_by_x11_channel: session %d "
2061 "channel %d", s->self, id);
2066 debug("session_by_x11_channel: unknown channel %d", id);
2072 session_by_pid(pid_t pid)
2075 debug("session_by_pid: pid %ld", (long)pid);
2076 for (i = 0; i < sessions_nalloc; i++) {
2077 Session *s = &sessions[i];
2078 if (s->used && s->pid == pid)
2081 error("session_by_pid: unknown pid %ld", (long)pid);
2087 session_window_change_req(Session *s)
2089 s->col = packet_get_int();
2090 s->row = packet_get_int();
2091 s->xpixel = packet_get_int();
2092 s->ypixel = packet_get_int();
2094 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2099 session_pty_req(Session *s)
2105 debug("Allocating a pty not permitted for this authentication.");
2108 if (s->ttyfd != -1) {
2109 packet_disconnect("Protocol error: you already have a pty.");
2113 s->term = packet_get_string(&len);
2116 s->col = packet_get_int();
2117 s->row = packet_get_int();
2119 s->row = packet_get_int();
2120 s->col = packet_get_int();
2122 s->xpixel = packet_get_int();
2123 s->ypixel = packet_get_int();
2125 if (strcmp(s->term, "") == 0) {
2130 /* Allocate a pty and open it. */
2131 debug("Allocating pty.");
2132 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2139 error("session_pty_req: session %d alloc failed", s->self);
2142 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2144 /* for SSH1 the tty modes length is not given */
2146 n_bytes = packet_remaining();
2147 tty_parse_modes(s->ttyfd, &n_bytes);
2150 pty_setowner(s->pw, s->tty);
2152 /* Set window size from the packet. */
2153 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2156 session_proctitle(s);
2161 session_subsystem_req(Session *s)
2166 char *prog, *cmd, *subsys = packet_get_string(&len);
2170 logit("subsystem request for %.100s", subsys);
2172 for (i = 0; i < options.num_subsystems; i++) {
2173 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2174 prog = options.subsystem_command[i];
2175 cmd = options.subsystem_args[i];
2176 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2177 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2178 debug("subsystem: %s", prog);
2180 if (stat(prog, &st) < 0)
2181 debug("subsystem: cannot stat %s: %s",
2182 prog, strerror(errno));
2183 s->is_subsystem = SUBSYSTEM_EXT;
2184 debug("subsystem: exec() %s", cmd);
2186 success = do_exec(s, cmd) == 0;
2192 logit("subsystem request for %.100s failed, subsystem not found",
2200 session_x11_req(Session *s)
2204 if (s->auth_proto != NULL || s->auth_data != NULL) {
2205 error("session_x11_req: session %d: "
2206 "x11 forwarding already active", s->self);
2209 s->single_connection = packet_get_char();
2210 s->auth_proto = packet_get_string(NULL);
2211 s->auth_data = packet_get_string(NULL);
2212 s->screen = packet_get_int();
2215 success = session_setup_x11fwd(s);
2217 xfree(s->auth_proto);
2218 xfree(s->auth_data);
2219 s->auth_proto = NULL;
2220 s->auth_data = NULL;
2226 session_shell_req(Session *s)
2229 return do_exec(s, NULL) == 0;
2233 session_exec_req(Session *s)
2237 char *command = packet_get_string(&len);
2239 success = do_exec(s, command) == 0;
2245 session_break_req(Session *s)
2248 packet_get_int(); /* ignored */
2251 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
2257 session_env_req(Session *s)
2260 u_int name_len, val_len, i;
2262 name = packet_get_string(&name_len);
2263 val = packet_get_string(&val_len);
2266 /* Don't set too many environment variables */
2267 if (s->num_env > 128) {
2268 debug2("Ignoring env request %s: too many env vars", name);
2272 for (i = 0; i < options.num_accept_env; i++) {
2273 if (match_pattern(name, options.accept_env[i])) {
2274 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2275 s->env = xrealloc(s->env, s->num_env + 1,
2277 s->env[s->num_env].name = name;
2278 s->env[s->num_env].val = val;
2283 debug2("Ignoring env request %s: disallowed name", name);
2292 session_auth_agent_req(Session *s)
2294 static int called = 0;
2296 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2297 debug("session_auth_agent_req: no_agent_forwarding_flag");
2304 return auth_input_request_forwarding(s->pw);
2309 session_input_channel_req(Channel *c, const char *rtype)
2314 if ((s = session_by_channel(c->self)) == NULL) {
2315 logit("session_input_channel_req: no session %d req %.100s",
2319 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2322 * a session is in LARVAL state until a shell, a command
2323 * or a subsystem is executed
2325 if (c->type == SSH_CHANNEL_LARVAL) {
2326 if (strcmp(rtype, "shell") == 0) {
2327 success = session_shell_req(s);
2328 } else if (strcmp(rtype, "exec") == 0) {
2329 success = session_exec_req(s);
2330 } else if (strcmp(rtype, "pty-req") == 0) {
2331 success = session_pty_req(s);
2332 } else if (strcmp(rtype, "x11-req") == 0) {
2333 success = session_x11_req(s);
2334 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2335 success = session_auth_agent_req(s);
2336 } else if (strcmp(rtype, "subsystem") == 0) {
2337 success = session_subsystem_req(s);
2338 } else if (strcmp(rtype, "env") == 0) {
2339 success = session_env_req(s);
2342 if (strcmp(rtype, "window-change") == 0) {
2343 success = session_window_change_req(s);
2344 } else if (strcmp(rtype, "break") == 0) {
2345 success = session_break_req(s);
2352 session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
2355 fatal("session_set_fds: called for proto != 2.0");
2357 * now that have a child and a pipe to the child,
2358 * we can activate our channel and register the fd's
2360 if (s->chanid == -1)
2361 fatal("no channel for session %d", s->self);
2362 channel_set_fds(s->chanid,
2364 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2365 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2369 * Function to perform pty cleanup. Also called if we get aborted abnormally
2370 * (e.g., due to a dropped connection).
2373 session_pty_cleanup2(Session *s)
2376 error("session_pty_cleanup: no session");
2382 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2384 /* Record that the user has logged out. */
2386 record_logout(s->pid, s->tty, s->pw->pw_name);
2388 /* Release the pseudo-tty. */
2390 pty_release(s->tty);
2393 * Close the server side of the socket pairs. We must do this after
2394 * the pty cleanup, so that another process doesn't get this pty
2395 * while we're still cleaning up.
2397 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2398 error("close(s->ptymaster/%d): %s",
2399 s->ptymaster, strerror(errno));
2401 /* unlink pty from session */
2406 session_pty_cleanup(Session *s)
2408 PRIVSEP(session_pty_cleanup2(s));
2414 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2429 return "SIG@openssh.com";
2433 session_close_x11(int id)
2437 if ((c = channel_by_id(id)) == NULL) {
2438 debug("session_close_x11: x11 channel %d missing", id);
2440 /* Detach X11 listener */
2441 debug("session_close_x11: detach x11 channel %d", id);
2442 channel_cancel_cleanup(id);
2443 if (c->ostate != CHAN_OUTPUT_CLOSED)
2449 session_close_single_x11(int id, void *arg)
2454 debug3("session_close_single_x11: channel %d", id);
2455 channel_cancel_cleanup(id);
2456 if ((s = session_by_x11_channel(id)) == NULL)
2457 fatal("session_close_single_x11: no x11 channel %d", id);
2458 for (i = 0; s->x11_chanids[i] != -1; i++) {
2459 debug("session_close_single_x11: session %d: "
2460 "closing channel %d", s->self, s->x11_chanids[i]);
2462 * The channel "id" is already closing, but make sure we
2463 * close all of its siblings.
2465 if (s->x11_chanids[i] != id)
2466 session_close_x11(s->x11_chanids[i]);
2468 xfree(s->x11_chanids);
2469 s->x11_chanids = NULL;
2474 if (s->auth_proto) {
2475 xfree(s->auth_proto);
2476 s->auth_proto = NULL;
2479 xfree(s->auth_data);
2480 s->auth_data = NULL;
2482 if (s->auth_display) {
2483 xfree(s->auth_display);
2484 s->auth_display = NULL;
2489 session_exit_message(Session *s, int status)
2493 if ((c = channel_lookup(s->chanid)) == NULL)
2494 fatal("session_exit_message: session %d: no channel %d",
2495 s->self, s->chanid);
2496 debug("session_exit_message: session %d channel %d pid %ld",
2497 s->self, s->chanid, (long)s->pid);
2499 if (WIFEXITED(status)) {
2500 channel_request_start(s->chanid, "exit-status", 0);
2501 packet_put_int(WEXITSTATUS(status));
2503 } else if (WIFSIGNALED(status)) {
2504 channel_request_start(s->chanid, "exit-signal", 0);
2505 packet_put_cstring(sig2name(WTERMSIG(status)));
2507 packet_put_char(WCOREDUMP(status)? 1 : 0);
2508 #else /* WCOREDUMP */
2510 #endif /* WCOREDUMP */
2511 packet_put_cstring("");
2512 packet_put_cstring("");
2515 /* Some weird exit cause. Just exit. */
2516 packet_disconnect("wait returned status %04x.", status);
2519 /* disconnect channel */
2520 debug("session_exit_message: release channel %d", s->chanid);
2523 * Adjust cleanup callback attachment to send close messages when
2524 * the channel gets EOF. The session will be then be closed
2525 * by session_close_by_channel when the childs close their fds.
2527 channel_register_cleanup(c->self, session_close_by_channel, 1);
2530 * emulate a write failure with 'chan_write_failed', nobody will be
2531 * interested in data we write.
2532 * Note that we must not call 'chan_read_failed', since there could
2533 * be some more data waiting in the pipe.
2535 if (c->ostate != CHAN_OUTPUT_CLOSED)
2536 chan_write_failed(c);
2540 session_close(Session *s)
2544 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2546 session_pty_cleanup(s);
2552 xfree(s->x11_chanids);
2553 if (s->auth_display)
2554 xfree(s->auth_display);
2556 xfree(s->auth_data);
2558 xfree(s->auth_proto);
2559 if (s->env != NULL) {
2560 for (i = 0; i < s->num_env; i++) {
2561 xfree(s->env[i].name);
2562 xfree(s->env[i].val);
2566 session_proctitle(s);
2567 session_unused(s->self);
2571 session_close_by_pid(pid_t pid, int status)
2573 Session *s = session_by_pid(pid);
2575 debug("session_close_by_pid: no session for pid %ld",
2579 if (s->chanid != -1)
2580 session_exit_message(s, status);
2582 session_pty_cleanup(s);
2587 * this is called when a channel dies before
2588 * the session 'child' itself dies
2591 session_close_by_channel(int id, void *arg)
2593 Session *s = session_by_channel(id);
2597 debug("session_close_by_channel: no session for id %d", id);
2600 debug("session_close_by_channel: channel %d child %ld",
2603 debug("session_close_by_channel: channel %d: has child", id);
2605 * delay detach of session, but release pty, since
2606 * the fd's to the child are already closed
2609 session_pty_cleanup(s);
2612 /* detach by removing callback */
2613 channel_cancel_cleanup(s->chanid);
2615 /* Close any X11 listeners associated with this session */
2616 if (s->x11_chanids != NULL) {
2617 for (i = 0; s->x11_chanids[i] != -1; i++) {
2618 session_close_x11(s->x11_chanids[i]);
2619 s->x11_chanids[i] = -1;
2628 session_destroy_all(void (*closefunc)(Session *))
2631 for (i = 0; i < sessions_nalloc; i++) {
2632 Session *s = &sessions[i];
2634 if (closefunc != NULL)
2643 session_tty_list(void)
2645 static char buf[1024];
2650 for (i = 0; i < sessions_nalloc; i++) {
2651 Session *s = &sessions[i];
2652 if (s->used && s->ttyfd != -1) {
2654 if (strncmp(s->tty, "/dev/", 5) != 0) {
2655 cp = strrchr(s->tty, '/');
2656 cp = (cp == NULL) ? s->tty : cp + 1;
2661 strlcat(buf, ",", sizeof buf);
2662 strlcat(buf, cp, sizeof buf);
2666 strlcpy(buf, "notty", sizeof buf);
2671 session_proctitle(Session *s)
2674 error("no user for session %d", s->self);
2676 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2680 session_setup_x11fwd(Session *s)
2683 char display[512], auth_display[512];
2684 char hostname[MAXHOSTNAMELEN];
2687 if (no_x11_forwarding_flag) {
2688 packet_send_debug("X11 forwarding disabled in user configuration file.");
2691 if (!options.x11_forwarding) {
2692 debug("X11 forwarding disabled in server configuration file.");
2695 if (!options.xauth_location ||
2696 (stat(options.xauth_location, &st) == -1)) {
2697 packet_send_debug("No xauth program; cannot forward with spoofing.");
2700 if (options.use_login) {
2701 packet_send_debug("X11 forwarding disabled; "
2702 "not compatible with UseLogin=yes.");
2705 if (s->display != NULL) {
2706 debug("X11 display already set.");
2709 if (x11_create_display_inet(options.x11_display_offset,
2710 options.x11_use_localhost, s->single_connection,
2711 &s->display_number, &s->x11_chanids) == -1) {
2712 debug("x11_create_display_inet failed.");
2715 for (i = 0; s->x11_chanids[i] != -1; i++) {
2716 channel_register_cleanup(s->x11_chanids[i],
2717 session_close_single_x11, 0);
2720 /* Set up a suitable value for the DISPLAY variable. */
2721 if (gethostname(hostname, sizeof(hostname)) < 0)
2722 fatal("gethostname: %.100s", strerror(errno));
2724 * auth_display must be used as the displayname when the
2725 * authorization entry is added with xauth(1). This will be
2726 * different than the DISPLAY string for localhost displays.
2728 if (options.x11_use_localhost) {
2729 snprintf(display, sizeof display, "localhost:%u.%u",
2730 s->display_number, s->screen);
2731 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2732 s->display_number, s->screen);
2733 s->display = xstrdup(display);
2734 s->auth_display = xstrdup(auth_display);
2736 #ifdef IPADDR_IN_DISPLAY
2738 struct in_addr my_addr;
2740 he = gethostbyname(hostname);
2742 error("Can't get IP address for X11 DISPLAY.");
2743 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2746 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2747 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2748 s->display_number, s->screen);
2750 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2751 s->display_number, s->screen);
2753 s->display = xstrdup(display);
2754 s->auth_display = xstrdup(display);
2761 do_authenticated2(Authctxt *authctxt)
2763 server_loop2(authctxt);
2767 do_cleanup(Authctxt *authctxt)
2769 static int called = 0;
2771 debug("do_cleanup");
2773 /* no cleanup if we're in the child for login shell */
2777 /* avoid double cleanup */
2782 if (authctxt == NULL)
2786 if (options.use_pam) {
2788 sshpam_thread_cleanup();
2792 if (!authctxt->authenticated)
2796 if (options.kerberos_ticket_cleanup &&
2798 krb5_cleanup_proc(authctxt);
2802 if (compat20 && options.gss_cleanup_creds)
2803 ssh_gssapi_cleanup_creds();
2806 /* remove agent socket */
2807 auth_sock_cleanup_proc(authctxt->pw);
2810 * Cleanup ptys/utmp only if privsep is disabled,
2811 * or if running in monitor.
2813 if (!use_privsep || mm_is_monitor())
2814 session_destroy_all(session_pty_cleanup2);