1 /* $OpenBSD: session.c,v 1.256 2010/06/25 07:20:04 djm 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>
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, 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];
452 fatal("do_exec_no_pty: no session");
454 /* Allocate pipes for communicating with the program. */
456 error("%s: pipe in: %.100s", __func__, strerror(errno));
459 if (pipe(pout) < 0) {
460 error("%s: pipe out: %.100s", __func__, strerror(errno));
465 if (pipe(perr) < 0) {
466 error("%s: pipe err: %.100s", __func__,
475 int inout[2], err[2];
478 fatal("do_exec_no_pty: no session");
480 /* Uses socket pairs to communicate with the program. */
481 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
482 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
485 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
486 error("%s: socketpair #2: %.100s", __func__,
494 session_proctitle(s);
496 /* Fork the child. */
497 switch ((pid = fork())) {
499 error("%s: fork: %.100s", __func__, strerror(errno));
517 /* Child. Reinitialize the log since the pid has changed. */
518 log_init(__progname, options.log_level,
519 options.log_facility, log_stderr);
522 * Create a new session and process group since the 4.4BSD
523 * setlogin() affects the entire process group.
526 error("setsid failed: %.100s", strerror(errno));
530 * Redirect stdin. We close the parent side of the socket
531 * pair, and make the child side the standard input.
534 if (dup2(pin[0], 0) < 0)
535 perror("dup2 stdin");
538 /* Redirect stdout. */
540 if (dup2(pout[1], 1) < 0)
541 perror("dup2 stdout");
544 /* Redirect stderr. */
546 if (dup2(perr[1], 2) < 0)
547 perror("dup2 stderr");
551 * Redirect stdin, stdout, and stderr. Stdin and stdout will
552 * use the same socket, as some programs (particularly rdist)
553 * seem to depend on it.
557 if (dup2(inout[0], 0) < 0) /* stdin */
558 perror("dup2 stdin");
559 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
560 perror("dup2 stdout");
562 if (dup2(err[0], 2) < 0) /* stderr */
563 perror("dup2 stderr");
569 cray_init_job(s->pw); /* set up cray jid and tmpdir */
572 /* Do processing for the child (exec command etc). */
573 do_child(s, command);
580 signal(WJSIGNAL, cray_job_termination_handler);
583 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
587 /* Set interactive/non-interactive mode. */
588 packet_set_interactive(s->display != NULL);
591 * Clear loginmsg, since it's the child's responsibility to display
592 * it to the user, otherwise multiple sessions may accumulate
593 * multiple copies of the login messages.
595 buffer_clear(&loginmsg);
598 /* We are the parent. Close the child sides of the pipes. */
604 session_set_fds(s, pin[1], pout[0], perr[0],
607 /* Enter the interactive session. */
608 server_loop(pid, pin[1], pout[0], perr[0]);
609 /* server_loop has closed pin[1], pout[0], and perr[0]. */
612 /* We are the parent. Close the child sides of the socket pairs. */
617 * Enter the interactive session. Note: server_loop must be able to
618 * handle the case that fdin and fdout are the same.
621 session_set_fds(s, inout[1], inout[1], err[1],
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, 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.
897 if (options.print_motd) {
898 #ifdef HAVE_LOGIN_CAP
899 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
902 f = fopen("/etc/motd", "r");
905 while (fgets(buf, sizeof(buf), f))
914 * Check for quiet login, either .hushlogin or command given.
917 check_quietlogin(Session *s, const char *command)
920 struct passwd *pw = s->pw;
923 /* Return 1 if .hushlogin exists or a command given. */
926 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
927 #ifdef HAVE_LOGIN_CAP
928 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
931 if (stat(buf, &st) >= 0)
938 * Sets the value of the given variable in the environment. If the variable
939 * already exists, its value is overridden.
942 child_set_env(char ***envp, u_int *envsizep, const char *name,
950 * If we're passed an uninitialized list, allocate a single null
951 * entry before continuing.
953 if (*envp == NULL && *envsizep == 0) {
954 *envp = xmalloc(sizeof(char *));
960 * Find the slot where the value should be stored. If the variable
961 * already exists, we reuse the slot; otherwise we append a new slot
962 * at the end of the array, expanding if necessary.
965 namelen = strlen(name);
966 for (i = 0; env[i]; i++)
967 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
970 /* Reuse the slot. */
973 /* New variable. Expand if necessary. */
975 if (i >= envsize - 1) {
977 fatal("child_set_env: too many env vars");
979 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
982 /* Need to set the NULL pointer at end of array beyond the new slot. */
986 /* Allocate space and format the variable in the appropriate slot. */
987 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
988 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
992 * Reads environment variables from the given file and adds/overrides them
993 * into the environment. If the file does not exist, this does nothing.
994 * Otherwise, it must consist of empty lines, comments (line starts with '#')
995 * and assignments of the form name=value. No other forms are allowed.
998 read_environment_file(char ***env, u_int *envsize,
999 const char *filename)
1006 f = fopen(filename, "r");
1010 while (fgets(buf, sizeof(buf), f)) {
1011 if (++lineno > 1000)
1012 fatal("Too many lines in environment file %s", filename);
1013 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1015 if (!*cp || *cp == '#' || *cp == '\n')
1018 cp[strcspn(cp, "\n")] = '\0';
1020 value = strchr(cp, '=');
1021 if (value == NULL) {
1022 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1027 * Replace the equals sign by nul, and advance value to
1032 child_set_env(env, envsize, cp, value);
1037 #ifdef HAVE_ETC_DEFAULT_LOGIN
1039 * Return named variable from specified environment, or NULL if not present.
1042 child_get_env(char **env, const char *name)
1048 for (i=0; env[i] != NULL; i++)
1049 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1050 return(env[i] + len + 1);
1055 * Read /etc/default/login.
1056 * We pick up the PATH (or SUPATH for root) and UMASK.
1059 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1061 char **tmpenv = NULL, *var;
1062 u_int i, tmpenvsize = 0;
1066 * We don't want to copy the whole file to the child's environment,
1067 * so we use a temporary environment and copy the variables we're
1070 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1076 var = child_get_env(tmpenv, "SUPATH");
1078 var = child_get_env(tmpenv, "PATH");
1080 child_set_env(env, envsize, "PATH", var);
1082 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1083 if (sscanf(var, "%5lo", &mask) == 1)
1084 umask((mode_t)mask);
1086 for (i = 0; tmpenv[i] != NULL; i++)
1090 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1093 copy_environment(char **source, char ***env, u_int *envsize)
1095 char *var_name, *var_val;
1101 for(i = 0; source[i] != NULL; i++) {
1102 var_name = xstrdup(source[i]);
1103 if ((var_val = strstr(var_name, "=")) == NULL) {
1109 debug3("Copy environment: %s=%s", var_name, var_val);
1110 child_set_env(env, envsize, var_name, var_val);
1117 do_setup_env(Session *s, const char *shell)
1122 struct passwd *pw = s->pw;
1123 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1127 /* Initialize the environment. */
1129 env = xcalloc(envsize, sizeof(char *));
1134 * The Windows environment contains some setting which are
1135 * important for a running system. They must not be dropped.
1140 p = fetch_windows_environment();
1141 copy_environment(p, &env, &envsize);
1142 free_windows_environment(p);
1147 /* Allow any GSSAPI methods that we've used to alter
1148 * the childs environment as they see fit
1150 ssh_gssapi_do_child(&env, &envsize);
1153 if (!options.use_login) {
1154 /* Set basic environment. */
1155 for (i = 0; i < s->num_env; i++)
1156 child_set_env(&env, &envsize, s->env[i].name,
1159 child_set_env(&env, &envsize, "USER", pw->pw_name);
1160 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1162 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1164 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1165 #ifdef HAVE_LOGIN_CAP
1166 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1167 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1169 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1170 #else /* HAVE_LOGIN_CAP */
1171 # ifndef HAVE_CYGWIN
1173 * There's no standard path on Windows. The path contains
1174 * important components pointing to the system directories,
1175 * needed for loading shared libraries. So the path better
1176 * remains intact here.
1178 # ifdef HAVE_ETC_DEFAULT_LOGIN
1179 read_etc_default_login(&env, &envsize, pw->pw_uid);
1180 path = child_get_env(env, "PATH");
1181 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1182 if (path == NULL || *path == '\0') {
1183 child_set_env(&env, &envsize, "PATH",
1184 s->pw->pw_uid == 0 ?
1185 SUPERUSER_PATH : _PATH_STDPATH);
1187 # endif /* HAVE_CYGWIN */
1188 #endif /* HAVE_LOGIN_CAP */
1190 snprintf(buf, sizeof buf, "%.200s/%.50s",
1191 _PATH_MAILDIR, pw->pw_name);
1192 child_set_env(&env, &envsize, "MAIL", buf);
1194 /* Normal systems set SHELL by default. */
1195 child_set_env(&env, &envsize, "SHELL", shell);
1198 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1200 /* Set custom environment options from RSA authentication. */
1201 if (!options.use_login) {
1202 while (custom_environment) {
1203 struct envstring *ce = custom_environment;
1206 for (i = 0; str[i] != '=' && str[i]; i++)
1208 if (str[i] == '=') {
1210 child_set_env(&env, &envsize, str, str + i + 1);
1212 custom_environment = ce->next;
1218 /* SSH_CLIENT deprecated */
1219 snprintf(buf, sizeof buf, "%.50s %d %d",
1220 get_remote_ipaddr(), get_remote_port(), get_local_port());
1221 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1223 laddr = get_local_ipaddr(packet_get_connection_in());
1224 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1225 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1227 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1230 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1232 child_set_env(&env, &envsize, "TERM", s->term);
1234 child_set_env(&env, &envsize, "DISPLAY", s->display);
1235 if (original_command)
1236 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1240 if (cray_tmpdir[0] != '\0')
1241 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1242 #endif /* _UNICOS */
1245 * Since we clear KRB5CCNAME at startup, if it's set now then it
1246 * must have been set by a native authentication method (eg AIX or
1247 * SIA), so copy it to the child.
1252 if ((cp = getenv("KRB5CCNAME")) != NULL)
1253 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1260 if ((cp = getenv("AUTHSTATE")) != NULL)
1261 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1262 read_environment_file(&env, &envsize, "/etc/environment");
1266 if (s->authctxt->krb5_ccname)
1267 child_set_env(&env, &envsize, "KRB5CCNAME",
1268 s->authctxt->krb5_ccname);
1272 * Pull in any environment variables that may have
1275 if (options.use_pam) {
1278 p = fetch_pam_child_environment();
1279 copy_environment(p, &env, &envsize);
1280 free_pam_environment(p);
1282 p = fetch_pam_environment();
1283 copy_environment(p, &env, &envsize);
1284 free_pam_environment(p);
1286 #endif /* USE_PAM */
1288 if (auth_sock_name != NULL)
1289 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1292 /* read $HOME/.ssh/environment. */
1293 if (options.permit_user_env && !options.use_login) {
1294 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1295 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1296 read_environment_file(&env, &envsize, buf);
1299 /* dump the environment */
1300 fprintf(stderr, "Environment:\n");
1301 for (i = 0; env[i]; i++)
1302 fprintf(stderr, " %.200s\n", env[i]);
1308 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1309 * first in this order).
1312 do_rc_files(Session *s, const char *shell)
1320 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1322 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1323 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1324 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1325 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1326 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1328 fprintf(stderr, "Running %s\n", cmd);
1329 f = popen(cmd, "w");
1332 fprintf(f, "%s %s\n", s->auth_proto,
1336 fprintf(stderr, "Could not run %s\n",
1338 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1340 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1341 _PATH_SSH_SYSTEM_RC);
1342 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1345 fprintf(f, "%s %s\n", s->auth_proto,
1349 fprintf(stderr, "Could not run %s\n",
1350 _PATH_SSH_SYSTEM_RC);
1351 } else if (do_xauth && options.xauth_location != NULL) {
1352 /* Add authority data to .Xauthority if appropriate. */
1355 "Running %.500s remove %.100s\n",
1356 options.xauth_location, s->auth_display);
1358 "%.500s add %.100s %.100s %.100s\n",
1359 options.xauth_location, s->auth_display,
1360 s->auth_proto, s->auth_data);
1362 snprintf(cmd, sizeof cmd, "%s -q -",
1363 options.xauth_location);
1364 f = popen(cmd, "w");
1366 fprintf(f, "remove %s\n",
1368 fprintf(f, "add %s %s %s\n",
1369 s->auth_display, s->auth_proto,
1373 fprintf(stderr, "Could not run %s\n",
1380 do_nologin(struct passwd *pw)
1383 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1386 #ifdef HAVE_LOGIN_CAP
1387 if (login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1389 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1391 if (pw->pw_uid == 0)
1395 if (stat(nl, &sb) == -1) {
1401 /* /etc/nologin exists. Print its contents if we can and exit. */
1402 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1403 if ((f = fopen(nl, "r")) != NULL) {
1404 while (fgets(buf, sizeof(buf), f))
1412 * Chroot into a directory after checking it for safety: all path components
1413 * must be root-owned directories with strict permissions.
1416 safely_chroot(const char *path, uid_t uid)
1419 char component[MAXPATHLEN];
1423 fatal("chroot path does not begin at root");
1424 if (strlen(path) >= sizeof(component))
1425 fatal("chroot path too long");
1428 * Descend the path, checking that each component is a
1429 * root-owned directory with strict permissions.
1431 for (cp = path; cp != NULL;) {
1432 if ((cp = strchr(cp, '/')) == NULL)
1433 strlcpy(component, path, sizeof(component));
1436 memcpy(component, path, cp - path);
1437 component[cp - path] = '\0';
1440 debug3("%s: checking '%s'", __func__, component);
1442 if (stat(component, &st) != 0)
1443 fatal("%s: stat(\"%s\"): %s", __func__,
1444 component, strerror(errno));
1445 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1446 fatal("bad ownership or modes for chroot "
1447 "directory %s\"%s\"",
1448 cp == NULL ? "" : "component ", component);
1449 if (!S_ISDIR(st.st_mode))
1450 fatal("chroot path %s\"%s\" is not a directory",
1451 cp == NULL ? "" : "component ", component);
1455 if (chdir(path) == -1)
1456 fatal("Unable to chdir to chroot path \"%s\": "
1457 "%s", path, strerror(errno));
1458 if (chroot(path) == -1)
1459 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1460 if (chdir("/") == -1)
1461 fatal("%s: chdir(/) after chroot: %s",
1462 __func__, strerror(errno));
1463 verbose("Changed root directory to \"%s\"", path);
1466 /* Set login name, uid, gid, and groups. */
1468 do_setusercontext(struct passwd *pw)
1470 char *chroot_path, *tmp;
1473 /* Cache selinux status for later use */
1474 (void)ssh_selinux_enabled();
1478 if (getuid() == 0 || geteuid() == 0)
1479 #endif /* HAVE_CYGWIN */
1481 #ifdef HAVE_LOGIN_CAP
1486 if (options.use_pam) {
1487 do_pam_setcred(use_privsep);
1489 # endif /* USE_PAM */
1490 if (setusercontext(lc, pw, pw->pw_uid,
1491 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1492 perror("unable to set user context");
1496 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1497 /* Sets login uid for accounting */
1498 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1499 error("setluid: %s", strerror(errno));
1500 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1502 if (setlogin(pw->pw_name) < 0)
1503 error("setlogin failed: %s", strerror(errno));
1504 if (setgid(pw->pw_gid) < 0) {
1508 /* Initialize the group list. */
1509 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1510 perror("initgroups");
1516 * PAM credentials may take the form of supplementary groups.
1517 * These will have been wiped by the above initgroups() call.
1518 * Reestablish them here.
1520 if (options.use_pam) {
1521 do_pam_setcred(use_privsep);
1523 # endif /* USE_PAM */
1524 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1525 irix_setusercontext(pw);
1526 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1531 if (set_id(pw->pw_name) != 0) {
1534 # endif /* USE_LIBIAF */
1536 #ifdef HAVE_SETPCRED
1538 * If we have a chroot directory, we set all creds except real
1539 * uid which we will need for chroot. If we don't have a
1540 * chroot directory, we don't override anything.
1543 char **creds = NULL, *chroot_creds[] =
1544 { "REAL_USER=root", NULL };
1546 if (options.chroot_directory != NULL &&
1547 strcasecmp(options.chroot_directory, "none") != 0)
1548 creds = chroot_creds;
1550 if (setpcred(pw->pw_name, creds) == -1)
1551 fatal("Failed to set process credentials");
1553 #endif /* HAVE_SETPCRED */
1556 ssh_selinux_setup_exec_context(pw->pw_name);
1559 if (options.chroot_directory != NULL &&
1560 strcasecmp(options.chroot_directory, "none") != 0) {
1561 tmp = tilde_expand_filename(options.chroot_directory,
1563 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1564 "u", pw->pw_name, (char *)NULL);
1565 safely_chroot(chroot_path, pw->pw_uid);
1570 #ifdef HAVE_LOGIN_CAP
1571 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1572 perror("unable to set user context (setuser)");
1576 /* Permanently switch to the desired uid. */
1577 permanently_set_uid(pw);
1581 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1582 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1586 do_pwchange(Session *s)
1589 fprintf(stderr, "WARNING: Your password has expired.\n");
1590 if (s->ttyfd != -1) {
1592 "You must change your password now and login again!\n");
1593 #ifdef PASSWD_NEEDS_USERNAME
1594 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1597 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1602 "Password change required but no TTY available.\n");
1608 launch_login(struct passwd *pw, const char *hostname)
1610 /* Launch login(1). */
1612 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1613 #ifdef xxxLOGIN_NEEDS_TERM
1614 (s->term ? s->term : "unknown"),
1615 #endif /* LOGIN_NEEDS_TERM */
1616 #ifdef LOGIN_NO_ENDOPT
1617 "-p", "-f", pw->pw_name, (char *)NULL);
1619 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1622 /* Login couldn't be executed, die. */
1629 child_close_fds(void)
1633 if (packet_get_connection_in() == packet_get_connection_out())
1634 close(packet_get_connection_in());
1636 close(packet_get_connection_in());
1637 close(packet_get_connection_out());
1640 * Close all descriptors related to channels. They will still remain
1641 * open in the parent.
1643 /* XXX better use close-on-exec? -markus */
1644 channel_close_all();
1647 * Close any extra file descriptors. Note that there may still be
1648 * descriptors left by system functions. They will be closed later.
1653 * Close any extra open file descriptors so that we don't have them
1654 * hanging around in clients. Note that we want to do this after
1655 * initgroups, because at least on Solaris 2.3 it leaves file
1658 for (i = 3; i < 64; i++)
1663 * Performs common processing for the child, such as setting up the
1664 * environment, closing extra file descriptors, setting the user and group
1665 * ids, and executing the command or shell.
1669 do_child(Session *s, const char *command)
1671 extern char **environ;
1673 char *argv[ARGV_MAX];
1674 const char *shell, *shell0, *hostname = NULL;
1675 struct passwd *pw = s->pw;
1678 /* remove hostkey from the child's memory */
1679 destroy_sensitive_data();
1681 /* Force a password change */
1682 if (s->authctxt->force_pwchange) {
1683 do_setusercontext(pw);
1689 /* login(1) is only called if we execute the login shell */
1690 if (options.use_login && command != NULL)
1691 options.use_login = 0;
1694 cray_setup(pw->pw_uid, pw->pw_name, command);
1695 #endif /* _UNICOS */
1698 * Login(1) does this as well, and it needs uid 0 for the "-h"
1699 * switch, so we let login(1) to this for us.
1701 if (!options.use_login) {
1703 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1704 if (!check_quietlogin(s, command))
1706 #else /* HAVE_OSF_SIA */
1707 /* When PAM is enabled we rely on it to do the nologin check */
1708 if (!options.use_pam)
1710 do_setusercontext(pw);
1712 * PAM session modules in do_setusercontext may have
1713 * generated messages, so if this in an interactive
1714 * login then display them too.
1716 if (!check_quietlogin(s, command))
1718 #endif /* HAVE_OSF_SIA */
1722 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1723 debug3("PAM session not opened, exiting");
1730 * Get the shell from the password data. An empty shell field is
1731 * legal, and means /bin/sh.
1733 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1736 * Make sure $SHELL points to the shell from the password file,
1737 * even if shell is overridden from login.conf
1739 env = do_setup_env(s, shell);
1741 #ifdef HAVE_LOGIN_CAP
1742 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1745 /* we have to stash the hostname before we close our socket. */
1746 if (options.use_login)
1747 hostname = get_remote_name_or_ip(utmp_len,
1750 * Close the connection descriptors; note that this is the child, and
1751 * the server will still have the socket open, and it is important
1752 * that we do not shutdown it. Note that the descriptors cannot be
1753 * closed before building the environment, as we call
1754 * get_remote_ipaddr there.
1759 * Must take new environment into use so that .ssh/rc,
1760 * /etc/ssh/sshrc and xauth are run in the proper environment.
1764 #if defined(KRB5) && defined(USE_AFS)
1766 * At this point, we check to see if AFS is active and if we have
1767 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1768 * if we can (and need to) extend the ticket into an AFS token. If
1769 * we don't do this, we run into potential problems if the user's
1770 * home directory is in AFS and it's not world-readable.
1773 if (options.kerberos_get_afs_token && k_hasafs() &&
1774 (s->authctxt->krb5_ctx != NULL)) {
1777 debug("Getting AFS token");
1781 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1782 krb5_afslog(s->authctxt->krb5_ctx,
1783 s->authctxt->krb5_fwd_ccache, cell, NULL);
1785 krb5_afslog_home(s->authctxt->krb5_ctx,
1786 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1790 /* Change current directory to the user's home directory. */
1791 if (chdir(pw->pw_dir) < 0) {
1792 /* Suppress missing homedir warning for chroot case */
1793 #ifdef HAVE_LOGIN_CAP
1794 r = login_getcapbool(lc, "requirehome", 0);
1796 if (r || options.chroot_directory == NULL ||
1797 strcasecmp(options.chroot_directory, "none") == 0)
1798 fprintf(stderr, "Could not chdir to home "
1799 "directory %s: %s\n", pw->pw_dir,
1805 closefrom(STDERR_FILENO + 1);
1807 if (!options.use_login)
1808 do_rc_files(s, shell);
1810 /* restore SIGPIPE for child */
1811 signal(SIGPIPE, SIG_DFL);
1813 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1814 printf("This service allows sftp connections only.\n");
1817 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1818 extern int optind, optreset;
1822 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1823 args = xstrdup(command ? command : "sftp-server");
1824 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1825 if (i < ARGV_MAX - 1)
1828 optind = optreset = 1;
1829 __progname = argv[0];
1831 ssh_selinux_change_context("sftpd_t");
1833 exit(sftp_server_main(i, argv, s->pw));
1838 if (options.use_login) {
1839 launch_login(pw, hostname);
1843 /* Get the last component of the shell name. */
1844 if ((shell0 = strrchr(shell, '/')) != NULL)
1850 * If we have no command, execute the shell. In this case, the shell
1851 * name to be passed in argv[0] is preceded by '-' to indicate that
1852 * this is a login shell.
1857 /* Start the shell. Set initial character to '-'. */
1860 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1861 >= sizeof(argv0) - 1) {
1867 /* Execute the shell. */
1870 execve(shell, argv, env);
1872 /* Executing the shell failed. */
1877 * Execute the command using the user's shell. This uses the -c
1878 * option to execute the command.
1880 argv[0] = (char *) shell0;
1882 argv[2] = (char *) command;
1884 execve(shell, argv, env);
1890 session_unused(int id)
1892 debug3("%s: session id %d unused", __func__, id);
1893 if (id >= options.max_sessions ||
1894 id >= sessions_nalloc) {
1895 fatal("%s: insane session id %d (max %d nalloc %d)",
1896 __func__, id, options.max_sessions, sessions_nalloc);
1898 bzero(&sessions[id], sizeof(*sessions));
1899 sessions[id].self = id;
1900 sessions[id].used = 0;
1901 sessions[id].chanid = -1;
1902 sessions[id].ptyfd = -1;
1903 sessions[id].ttyfd = -1;
1904 sessions[id].ptymaster = -1;
1905 sessions[id].x11_chanids = NULL;
1906 sessions[id].next_unused = sessions_first_unused;
1907 sessions_first_unused = id;
1915 if (sessions_first_unused == -1) {
1916 if (sessions_nalloc >= options.max_sessions)
1918 debug2("%s: allocate (allocated %d max %d)",
1919 __func__, sessions_nalloc, options.max_sessions);
1920 tmp = xrealloc(sessions, sessions_nalloc + 1,
1923 error("%s: cannot allocate %d sessions",
1924 __func__, sessions_nalloc + 1);
1928 session_unused(sessions_nalloc++);
1931 if (sessions_first_unused >= sessions_nalloc ||
1932 sessions_first_unused < 0) {
1933 fatal("%s: insane first_unused %d max %d nalloc %d",
1934 __func__, sessions_first_unused, options.max_sessions,
1938 s = &sessions[sessions_first_unused];
1940 fatal("%s: session %d already used",
1941 __func__, sessions_first_unused);
1943 sessions_first_unused = s->next_unused;
1945 s->next_unused = -1;
1946 debug("session_new: session %d", s->self);
1955 for (i = 0; i < sessions_nalloc; i++) {
1956 Session *s = &sessions[i];
1958 debug("dump: used %d next_unused %d session %d %p "
1959 "channel %d pid %ld",
1970 session_open(Authctxt *authctxt, int chanid)
1972 Session *s = session_new();
1973 debug("session_open: channel %d", chanid);
1975 error("no more sessions");
1978 s->authctxt = authctxt;
1979 s->pw = authctxt->pw;
1980 if (s->pw == NULL || !authctxt->valid)
1981 fatal("no user for session %d", s->self);
1982 debug("session_open: session %d: link with channel %d", s->self, chanid);
1988 session_by_tty(char *tty)
1991 for (i = 0; i < sessions_nalloc; i++) {
1992 Session *s = &sessions[i];
1993 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1994 debug("session_by_tty: session %d tty %s", i, tty);
1998 debug("session_by_tty: unknown tty %.100s", tty);
2004 session_by_channel(int id)
2007 for (i = 0; i < sessions_nalloc; i++) {
2008 Session *s = &sessions[i];
2009 if (s->used && s->chanid == id) {
2010 debug("session_by_channel: session %d channel %d",
2015 debug("session_by_channel: unknown channel %d", id);
2021 session_by_x11_channel(int id)
2025 for (i = 0; i < sessions_nalloc; i++) {
2026 Session *s = &sessions[i];
2028 if (s->x11_chanids == NULL || !s->used)
2030 for (j = 0; s->x11_chanids[j] != -1; j++) {
2031 if (s->x11_chanids[j] == id) {
2032 debug("session_by_x11_channel: session %d "
2033 "channel %d", s->self, id);
2038 debug("session_by_x11_channel: unknown channel %d", id);
2044 session_by_pid(pid_t pid)
2047 debug("session_by_pid: pid %ld", (long)pid);
2048 for (i = 0; i < sessions_nalloc; i++) {
2049 Session *s = &sessions[i];
2050 if (s->used && s->pid == pid)
2053 error("session_by_pid: unknown pid %ld", (long)pid);
2059 session_window_change_req(Session *s)
2061 s->col = packet_get_int();
2062 s->row = packet_get_int();
2063 s->xpixel = packet_get_int();
2064 s->ypixel = packet_get_int();
2066 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2071 session_pty_req(Session *s)
2077 debug("Allocating a pty not permitted for this authentication.");
2080 if (s->ttyfd != -1) {
2081 packet_disconnect("Protocol error: you already have a pty.");
2085 s->term = packet_get_string(&len);
2088 s->col = packet_get_int();
2089 s->row = packet_get_int();
2091 s->row = packet_get_int();
2092 s->col = packet_get_int();
2094 s->xpixel = packet_get_int();
2095 s->ypixel = packet_get_int();
2097 if (strcmp(s->term, "") == 0) {
2102 /* Allocate a pty and open it. */
2103 debug("Allocating pty.");
2104 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2111 error("session_pty_req: session %d alloc failed", s->self);
2114 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2116 /* for SSH1 the tty modes length is not given */
2118 n_bytes = packet_remaining();
2119 tty_parse_modes(s->ttyfd, &n_bytes);
2122 pty_setowner(s->pw, s->tty);
2124 /* Set window size from the packet. */
2125 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2128 session_proctitle(s);
2133 session_subsystem_req(Session *s)
2138 char *prog, *cmd, *subsys = packet_get_string(&len);
2142 logit("subsystem request for %.100s by user %s", subsys,
2145 for (i = 0; i < options.num_subsystems; i++) {
2146 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2147 prog = options.subsystem_command[i];
2148 cmd = options.subsystem_args[i];
2149 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2150 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2151 debug("subsystem: %s", prog);
2153 if (stat(prog, &st) < 0)
2154 debug("subsystem: cannot stat %s: %s",
2155 prog, strerror(errno));
2156 s->is_subsystem = SUBSYSTEM_EXT;
2157 debug("subsystem: exec() %s", cmd);
2159 success = do_exec(s, cmd) == 0;
2165 logit("subsystem request for %.100s failed, subsystem not found",
2173 session_x11_req(Session *s)
2177 if (s->auth_proto != NULL || s->auth_data != NULL) {
2178 error("session_x11_req: session %d: "
2179 "x11 forwarding already active", s->self);
2182 s->single_connection = packet_get_char();
2183 s->auth_proto = packet_get_string(NULL);
2184 s->auth_data = packet_get_string(NULL);
2185 s->screen = packet_get_int();
2188 success = session_setup_x11fwd(s);
2190 xfree(s->auth_proto);
2191 xfree(s->auth_data);
2192 s->auth_proto = NULL;
2193 s->auth_data = NULL;
2199 session_shell_req(Session *s)
2202 return do_exec(s, NULL) == 0;
2206 session_exec_req(Session *s)
2210 char *command = packet_get_string(&len);
2212 success = do_exec(s, command) == 0;
2218 session_break_req(Session *s)
2221 packet_get_int(); /* ignored */
2224 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
2230 session_env_req(Session *s)
2233 u_int name_len, val_len, i;
2235 name = packet_get_string(&name_len);
2236 val = packet_get_string(&val_len);
2239 /* Don't set too many environment variables */
2240 if (s->num_env > 128) {
2241 debug2("Ignoring env request %s: too many env vars", name);
2245 for (i = 0; i < options.num_accept_env; i++) {
2246 if (match_pattern(name, options.accept_env[i])) {
2247 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2248 s->env = xrealloc(s->env, s->num_env + 1,
2250 s->env[s->num_env].name = name;
2251 s->env[s->num_env].val = val;
2256 debug2("Ignoring env request %s: disallowed name", name);
2265 session_auth_agent_req(Session *s)
2267 static int called = 0;
2269 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2270 debug("session_auth_agent_req: no_agent_forwarding_flag");
2277 return auth_input_request_forwarding(s->pw);
2282 session_input_channel_req(Channel *c, const char *rtype)
2287 if ((s = session_by_channel(c->self)) == NULL) {
2288 logit("session_input_channel_req: no session %d req %.100s",
2292 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2295 * a session is in LARVAL state until a shell, a command
2296 * or a subsystem is executed
2298 if (c->type == SSH_CHANNEL_LARVAL) {
2299 if (strcmp(rtype, "shell") == 0) {
2300 success = session_shell_req(s);
2301 } else if (strcmp(rtype, "exec") == 0) {
2302 success = session_exec_req(s);
2303 } else if (strcmp(rtype, "pty-req") == 0) {
2304 success = session_pty_req(s);
2305 } else if (strcmp(rtype, "x11-req") == 0) {
2306 success = session_x11_req(s);
2307 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2308 success = session_auth_agent_req(s);
2309 } else if (strcmp(rtype, "subsystem") == 0) {
2310 success = session_subsystem_req(s);
2311 } else if (strcmp(rtype, "env") == 0) {
2312 success = session_env_req(s);
2315 if (strcmp(rtype, "window-change") == 0) {
2316 success = session_window_change_req(s);
2317 } else if (strcmp(rtype, "break") == 0) {
2318 success = session_break_req(s);
2325 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2329 fatal("session_set_fds: called for proto != 2.0");
2331 * now that have a child and a pipe to the child,
2332 * we can activate our channel and register the fd's
2334 if (s->chanid == -1)
2335 fatal("no channel for session %d", s->self);
2336 channel_set_fds(s->chanid,
2338 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2339 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2343 * Function to perform pty cleanup. Also called if we get aborted abnormally
2344 * (e.g., due to a dropped connection).
2347 session_pty_cleanup2(Session *s)
2350 error("session_pty_cleanup: no session");
2356 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2358 /* Record that the user has logged out. */
2360 record_logout(s->pid, s->tty, s->pw->pw_name);
2362 /* Release the pseudo-tty. */
2364 pty_release(s->tty);
2367 * Close the server side of the socket pairs. We must do this after
2368 * the pty cleanup, so that another process doesn't get this pty
2369 * while we're still cleaning up.
2371 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2372 error("close(s->ptymaster/%d): %s",
2373 s->ptymaster, strerror(errno));
2375 /* unlink pty from session */
2380 session_pty_cleanup(Session *s)
2382 PRIVSEP(session_pty_cleanup2(s));
2388 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2403 return "SIG@openssh.com";
2407 session_close_x11(int id)
2411 if ((c = channel_by_id(id)) == NULL) {
2412 debug("session_close_x11: x11 channel %d missing", id);
2414 /* Detach X11 listener */
2415 debug("session_close_x11: detach x11 channel %d", id);
2416 channel_cancel_cleanup(id);
2417 if (c->ostate != CHAN_OUTPUT_CLOSED)
2423 session_close_single_x11(int id, void *arg)
2428 debug3("session_close_single_x11: channel %d", id);
2429 channel_cancel_cleanup(id);
2430 if ((s = session_by_x11_channel(id)) == NULL)
2431 fatal("session_close_single_x11: no x11 channel %d", id);
2432 for (i = 0; s->x11_chanids[i] != -1; i++) {
2433 debug("session_close_single_x11: session %d: "
2434 "closing channel %d", s->self, s->x11_chanids[i]);
2436 * The channel "id" is already closing, but make sure we
2437 * close all of its siblings.
2439 if (s->x11_chanids[i] != id)
2440 session_close_x11(s->x11_chanids[i]);
2442 xfree(s->x11_chanids);
2443 s->x11_chanids = NULL;
2448 if (s->auth_proto) {
2449 xfree(s->auth_proto);
2450 s->auth_proto = NULL;
2453 xfree(s->auth_data);
2454 s->auth_data = NULL;
2456 if (s->auth_display) {
2457 xfree(s->auth_display);
2458 s->auth_display = NULL;
2463 session_exit_message(Session *s, int status)
2467 if ((c = channel_lookup(s->chanid)) == NULL)
2468 fatal("session_exit_message: session %d: no channel %d",
2469 s->self, s->chanid);
2470 debug("session_exit_message: session %d channel %d pid %ld",
2471 s->self, s->chanid, (long)s->pid);
2473 if (WIFEXITED(status)) {
2474 channel_request_start(s->chanid, "exit-status", 0);
2475 packet_put_int(WEXITSTATUS(status));
2477 } else if (WIFSIGNALED(status)) {
2478 channel_request_start(s->chanid, "exit-signal", 0);
2479 packet_put_cstring(sig2name(WTERMSIG(status)));
2481 packet_put_char(WCOREDUMP(status)? 1 : 0);
2482 #else /* WCOREDUMP */
2484 #endif /* WCOREDUMP */
2485 packet_put_cstring("");
2486 packet_put_cstring("");
2489 /* Some weird exit cause. Just exit. */
2490 packet_disconnect("wait returned status %04x.", status);
2493 /* disconnect channel */
2494 debug("session_exit_message: release channel %d", s->chanid);
2497 * Adjust cleanup callback attachment to send close messages when
2498 * the channel gets EOF. The session will be then be closed
2499 * by session_close_by_channel when the childs close their fds.
2501 channel_register_cleanup(c->self, session_close_by_channel, 1);
2504 * emulate a write failure with 'chan_write_failed', nobody will be
2505 * interested in data we write.
2506 * Note that we must not call 'chan_read_failed', since there could
2507 * be some more data waiting in the pipe.
2509 if (c->ostate != CHAN_OUTPUT_CLOSED)
2510 chan_write_failed(c);
2514 session_close(Session *s)
2518 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2520 session_pty_cleanup(s);
2526 xfree(s->x11_chanids);
2527 if (s->auth_display)
2528 xfree(s->auth_display);
2530 xfree(s->auth_data);
2532 xfree(s->auth_proto);
2533 if (s->env != NULL) {
2534 for (i = 0; i < s->num_env; i++) {
2535 xfree(s->env[i].name);
2536 xfree(s->env[i].val);
2540 session_proctitle(s);
2541 session_unused(s->self);
2545 session_close_by_pid(pid_t pid, int status)
2547 Session *s = session_by_pid(pid);
2549 debug("session_close_by_pid: no session for pid %ld",
2553 if (s->chanid != -1)
2554 session_exit_message(s, status);
2556 session_pty_cleanup(s);
2561 * this is called when a channel dies before
2562 * the session 'child' itself dies
2565 session_close_by_channel(int id, void *arg)
2567 Session *s = session_by_channel(id);
2571 debug("session_close_by_channel: no session for id %d", id);
2574 debug("session_close_by_channel: channel %d child %ld",
2577 debug("session_close_by_channel: channel %d: has child", id);
2579 * delay detach of session, but release pty, since
2580 * the fd's to the child are already closed
2583 session_pty_cleanup(s);
2586 /* detach by removing callback */
2587 channel_cancel_cleanup(s->chanid);
2589 /* Close any X11 listeners associated with this session */
2590 if (s->x11_chanids != NULL) {
2591 for (i = 0; s->x11_chanids[i] != -1; i++) {
2592 session_close_x11(s->x11_chanids[i]);
2593 s->x11_chanids[i] = -1;
2602 session_destroy_all(void (*closefunc)(Session *))
2605 for (i = 0; i < sessions_nalloc; i++) {
2606 Session *s = &sessions[i];
2608 if (closefunc != NULL)
2617 session_tty_list(void)
2619 static char buf[1024];
2624 for (i = 0; i < sessions_nalloc; i++) {
2625 Session *s = &sessions[i];
2626 if (s->used && s->ttyfd != -1) {
2628 if (strncmp(s->tty, "/dev/", 5) != 0) {
2629 cp = strrchr(s->tty, '/');
2630 cp = (cp == NULL) ? s->tty : cp + 1;
2635 strlcat(buf, ",", sizeof buf);
2636 strlcat(buf, cp, sizeof buf);
2640 strlcpy(buf, "notty", sizeof buf);
2645 session_proctitle(Session *s)
2648 error("no user for session %d", s->self);
2650 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2654 session_setup_x11fwd(Session *s)
2657 char display[512], auth_display[512];
2658 char hostname[MAXHOSTNAMELEN];
2661 if (no_x11_forwarding_flag) {
2662 packet_send_debug("X11 forwarding disabled in user configuration file.");
2665 if (!options.x11_forwarding) {
2666 debug("X11 forwarding disabled in server configuration file.");
2669 if (!options.xauth_location ||
2670 (stat(options.xauth_location, &st) == -1)) {
2671 packet_send_debug("No xauth program; cannot forward with spoofing.");
2674 if (options.use_login) {
2675 packet_send_debug("X11 forwarding disabled; "
2676 "not compatible with UseLogin=yes.");
2679 if (s->display != NULL) {
2680 debug("X11 display already set.");
2683 if (x11_create_display_inet(options.x11_display_offset,
2684 options.x11_use_localhost, s->single_connection,
2685 &s->display_number, &s->x11_chanids) == -1) {
2686 debug("x11_create_display_inet failed.");
2689 for (i = 0; s->x11_chanids[i] != -1; i++) {
2690 channel_register_cleanup(s->x11_chanids[i],
2691 session_close_single_x11, 0);
2694 /* Set up a suitable value for the DISPLAY variable. */
2695 if (gethostname(hostname, sizeof(hostname)) < 0)
2696 fatal("gethostname: %.100s", strerror(errno));
2698 * auth_display must be used as the displayname when the
2699 * authorization entry is added with xauth(1). This will be
2700 * different than the DISPLAY string for localhost displays.
2702 if (options.x11_use_localhost) {
2703 snprintf(display, sizeof display, "localhost:%u.%u",
2704 s->display_number, s->screen);
2705 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2706 s->display_number, s->screen);
2707 s->display = xstrdup(display);
2708 s->auth_display = xstrdup(auth_display);
2710 #ifdef IPADDR_IN_DISPLAY
2712 struct in_addr my_addr;
2714 he = gethostbyname(hostname);
2716 error("Can't get IP address for X11 DISPLAY.");
2717 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2720 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2721 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2722 s->display_number, s->screen);
2724 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2725 s->display_number, s->screen);
2727 s->display = xstrdup(display);
2728 s->auth_display = xstrdup(display);
2735 do_authenticated2(Authctxt *authctxt)
2737 server_loop2(authctxt);
2741 do_cleanup(Authctxt *authctxt)
2743 static int called = 0;
2745 debug("do_cleanup");
2747 /* no cleanup if we're in the child for login shell */
2751 /* avoid double cleanup */
2756 if (authctxt == NULL)
2760 if (options.use_pam) {
2762 sshpam_thread_cleanup();
2766 if (!authctxt->authenticated)
2770 if (options.kerberos_ticket_cleanup &&
2772 krb5_cleanup_proc(authctxt);
2776 if (compat20 && options.gss_cleanup_creds)
2777 ssh_gssapi_cleanup_creds();
2780 /* remove agent socket */
2781 auth_sock_cleanup_proc(authctxt->pw);
2784 * Cleanup ptys/utmp only if privsep is disabled,
2785 * or if running in monitor.
2787 if (!use_privsep || mm_is_monitor())
2788 session_destroy_all(session_pty_cleanup2);