1 /* $OpenBSD: session.c,v 1.230 2008/02/22 05:58:56 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>
80 #include "auth-options.h"
81 #include "pathnames.h"
85 #include "serverloop.h"
90 #include "monitor_wrap.h"
93 #if defined(KRB5) && defined(USE_AFS)
99 Session *session_new(void);
100 void session_set_fds(Session *, int, int, int);
101 void session_pty_cleanup(Session *);
102 void session_proctitle(Session *);
103 int session_setup_x11fwd(Session *);
104 void do_exec_pty(Session *, const char *);
105 void do_exec_no_pty(Session *, const char *);
106 void do_exec(Session *, const char *);
107 void do_login(Session *, const char *);
108 #ifdef LOGIN_NEEDS_UTMPX
109 static void do_pre_login(Session *s);
111 void do_child(Session *, const char *);
113 int check_quietlogin(Session *, const char *);
115 static void do_authenticated1(Authctxt *);
116 static void do_authenticated2(Authctxt *);
118 static int session_pty_req(Session *);
121 extern ServerOptions options;
122 extern char *__progname;
123 extern int log_stderr;
124 extern int debug_flag;
125 extern u_int utmp_len;
126 extern int startup_pipe;
127 extern void destroy_sensitive_data(void);
128 extern Buffer loginmsg;
130 /* original command from peer. */
131 const char *original_command = NULL;
134 #define MAX_SESSIONS 20
135 Session sessions[MAX_SESSIONS];
137 #define SUBSYSTEM_NONE 0
138 #define SUBSYSTEM_EXT 1
139 #define SUBSYSTEM_INT_SFTP 2
141 #ifdef HAVE_LOGIN_CAP
145 static int is_child = 0;
147 /* Name and directory of socket for authentication agent forwarding. */
148 static char *auth_sock_name = NULL;
149 static char *auth_sock_dir = NULL;
151 /* removes the agent forwarding socket */
154 auth_sock_cleanup_proc(struct passwd *pw)
156 if (auth_sock_name != NULL) {
157 temporarily_use_uid(pw);
158 unlink(auth_sock_name);
159 rmdir(auth_sock_dir);
160 auth_sock_name = NULL;
166 auth_input_request_forwarding(struct passwd * pw)
170 struct sockaddr_un sunaddr;
172 if (auth_sock_name != NULL) {
173 error("authentication forwarding requested twice.");
177 /* Temporarily drop privileged uid for mkdir/bind. */
178 temporarily_use_uid(pw);
180 /* Allocate a buffer for the socket name, and format the name. */
181 auth_sock_name = xmalloc(MAXPATHLEN);
182 auth_sock_dir = xmalloc(MAXPATHLEN);
183 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
185 /* Create private directory for socket */
186 if (mkdtemp(auth_sock_dir) == NULL) {
187 packet_send_debug("Agent forwarding disabled: "
188 "mkdtemp() failed: %.100s", strerror(errno));
190 xfree(auth_sock_name);
191 xfree(auth_sock_dir);
192 auth_sock_name = NULL;
193 auth_sock_dir = NULL;
196 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld",
197 auth_sock_dir, (long) getpid());
199 /* Create the socket. */
200 sock = socket(AF_UNIX, SOCK_STREAM, 0);
202 packet_disconnect("socket: %.100s", strerror(errno));
204 /* Bind it to the name. */
205 memset(&sunaddr, 0, sizeof(sunaddr));
206 sunaddr.sun_family = AF_UNIX;
207 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
209 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0)
210 packet_disconnect("bind: %.100s", strerror(errno));
212 /* Restore the privileged uid. */
215 /* Start listening on the socket. */
216 if (listen(sock, SSH_LISTEN_BACKLOG) < 0)
217 packet_disconnect("listen: %.100s", strerror(errno));
219 /* Allocate a channel for the authentication agent socket. */
220 nc = channel_new("auth socket",
221 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
222 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
223 0, "auth socket", 1);
224 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
229 display_loginmsg(void)
231 if (buffer_len(&loginmsg) > 0) {
232 buffer_append(&loginmsg, "\0", 1);
233 printf("%s", (char *)buffer_ptr(&loginmsg));
234 buffer_clear(&loginmsg);
239 do_authenticated(Authctxt *authctxt)
241 setproctitle("%s", authctxt->pw->pw_name);
243 /* setup the channel layer */
244 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
245 channel_permit_all_opens();
248 do_authenticated2(authctxt);
250 do_authenticated1(authctxt);
252 do_cleanup(authctxt);
256 * Prepares for an interactive session. This is called after the user has
257 * been successfully authenticated. During this message exchange, pseudo
258 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
259 * are requested, etc.
262 do_authenticated1(Authctxt *authctxt)
266 int success, type, screen_flag;
267 int enable_compression_after_reply = 0;
268 u_int proto_len, data_len, dlen, compression_level = 0;
272 error("no more sessions");
275 s->authctxt = authctxt;
276 s->pw = authctxt->pw;
279 * We stay in this loop until the client requests to execute a shell
285 /* Get a packet from the client. */
286 type = packet_read();
288 /* Process the packet. */
290 case SSH_CMSG_REQUEST_COMPRESSION:
291 compression_level = packet_get_int();
293 if (compression_level < 1 || compression_level > 9) {
294 packet_send_debug("Received invalid compression level %d.",
298 if (options.compression == COMP_NONE) {
299 debug2("compression disabled");
302 /* Enable compression after we have responded with SUCCESS. */
303 enable_compression_after_reply = 1;
307 case SSH_CMSG_REQUEST_PTY:
308 success = session_pty_req(s);
311 case SSH_CMSG_X11_REQUEST_FORWARDING:
312 s->auth_proto = packet_get_string(&proto_len);
313 s->auth_data = packet_get_string(&data_len);
315 screen_flag = packet_get_protocol_flags() &
316 SSH_PROTOFLAG_SCREEN_NUMBER;
317 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
319 if (packet_remaining() == 4) {
321 debug2("Buggy client: "
322 "X11 screen flag missing");
323 s->screen = packet_get_int();
328 success = session_setup_x11fwd(s);
330 xfree(s->auth_proto);
332 s->auth_proto = NULL;
337 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
338 if (no_agent_forwarding_flag || compat13) {
339 debug("Authentication agent forwarding not permitted for this authentication.");
342 debug("Received authentication agent forwarding request.");
343 success = auth_input_request_forwarding(s->pw);
346 case SSH_CMSG_PORT_FORWARD_REQUEST:
347 if (no_port_forwarding_flag) {
348 debug("Port forwarding not permitted for this authentication.");
351 if (!options.allow_tcp_forwarding) {
352 debug("Port forwarding not permitted.");
355 debug("Received TCP/IP port forwarding request.");
356 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
357 options.gateway_ports) < 0) {
358 debug("Port forwarding failed.");
364 case SSH_CMSG_MAX_PACKET_SIZE:
365 if (packet_set_maxsize(packet_get_int()) > 0)
369 case SSH_CMSG_EXEC_SHELL:
370 case SSH_CMSG_EXEC_CMD:
371 if (type == SSH_CMSG_EXEC_CMD) {
372 command = packet_get_string(&dlen);
373 debug("Exec command '%.500s'", command);
385 * Any unknown messages in this phase are ignored,
386 * and a failure message is returned.
388 logit("Unknown packet type received after authentication: %d", type);
390 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
394 /* Enable compression now that we have replied if appropriate. */
395 if (enable_compression_after_reply) {
396 enable_compression_after_reply = 0;
397 packet_start_compression(compression_level);
403 * This is called to fork and execute a command when we have no tty. This
404 * will call do_child from the child, and server_loop from the parent after
405 * setting up file descriptors and such.
408 do_exec_no_pty(Session *s, const char *command)
413 int pin[2], pout[2], perr[2];
414 /* Allocate pipes for communicating with the program. */
415 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
416 packet_disconnect("Could not create pipes: %.100s",
418 #else /* USE_PIPES */
419 int inout[2], err[2];
420 /* Uses socket pairs to communicate with the program. */
421 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
422 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
423 packet_disconnect("Could not create socket pairs: %.100s",
425 #endif /* USE_PIPES */
427 fatal("do_exec_no_pty: no session");
429 session_proctitle(s);
431 /* Fork the child. */
432 if ((pid = fork()) == 0) {
435 /* Child. Reinitialize the log since the pid has changed. */
436 log_init(__progname, options.log_level, options.log_facility, log_stderr);
439 * Create a new session and process group since the 4.4BSD
440 * setlogin() affects the entire process group.
443 error("setsid failed: %.100s", strerror(errno));
447 * Redirect stdin. We close the parent side of the socket
448 * pair, and make the child side the standard input.
451 if (dup2(pin[0], 0) < 0)
452 perror("dup2 stdin");
455 /* Redirect stdout. */
457 if (dup2(pout[1], 1) < 0)
458 perror("dup2 stdout");
461 /* Redirect stderr. */
463 if (dup2(perr[1], 2) < 0)
464 perror("dup2 stderr");
466 #else /* USE_PIPES */
468 * Redirect stdin, stdout, and stderr. Stdin and stdout will
469 * use the same socket, as some programs (particularly rdist)
470 * seem to depend on it.
474 if (dup2(inout[0], 0) < 0) /* stdin */
475 perror("dup2 stdin");
476 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
477 perror("dup2 stdout");
478 if (dup2(err[0], 2) < 0) /* stderr */
479 perror("dup2 stderr");
480 #endif /* USE_PIPES */
483 cray_init_job(s->pw); /* set up cray jid and tmpdir */
486 /* Do processing for the child (exec command etc). */
487 do_child(s, command);
491 signal(WJSIGNAL, cray_job_termination_handler);
495 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
498 packet_disconnect("fork failed: %.100s", strerror(errno));
500 /* Set interactive/non-interactive mode. */
501 packet_set_interactive(s->display != NULL);
503 /* We are the parent. Close the child sides of the pipes. */
509 if (s->is_subsystem) {
513 session_set_fds(s, pin[1], pout[0], perr[0]);
515 /* Enter the interactive session. */
516 server_loop(pid, pin[1], pout[0], perr[0]);
517 /* server_loop has closed pin[1], pout[0], and perr[0]. */
519 #else /* USE_PIPES */
520 /* We are the parent. Close the child sides of the socket pairs. */
525 * Clear loginmsg, since it's the child's responsibility to display
526 * it to the user, otherwise multiple sessions may accumulate
527 * multiple copies of the login messages.
529 buffer_clear(&loginmsg);
532 * Enter the interactive session. Note: server_loop must be able to
533 * handle the case that fdin and fdout are the same.
536 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
538 server_loop(pid, inout[1], inout[1], err[1]);
539 /* server_loop has closed inout[1] and err[1]. */
541 #endif /* USE_PIPES */
545 * This is called to fork and execute a command when we have a tty. This
546 * will call do_child from the child, and server_loop from the parent after
547 * setting up file descriptors, controlling tty, updating wtmp, utmp,
548 * lastlog, and other such operations.
551 do_exec_pty(Session *s, const char *command)
553 int fdout, ptyfd, ttyfd, ptymaster;
557 fatal("do_exec_pty: no session");
561 /* Fork the child. */
562 if ((pid = fork()) == 0) {
565 /* Child. Reinitialize the log because the pid has changed. */
566 log_init(__progname, options.log_level, options.log_facility, log_stderr);
567 /* Close the master side of the pseudo tty. */
570 /* Make the pseudo tty our controlling tty. */
571 pty_make_controlling_tty(&ttyfd, s->tty);
573 /* Redirect stdin/stdout/stderr from the pseudo tty. */
574 if (dup2(ttyfd, 0) < 0)
575 error("dup2 stdin: %s", strerror(errno));
576 if (dup2(ttyfd, 1) < 0)
577 error("dup2 stdout: %s", strerror(errno));
578 if (dup2(ttyfd, 2) < 0)
579 error("dup2 stderr: %s", strerror(errno));
581 /* Close the extra descriptor for the pseudo tty. */
584 /* record login, etc. similar to login(1) */
586 if (!(options.use_login && command == NULL)) {
588 cray_init_job(s->pw); /* set up cray jid and tmpdir */
590 do_login(s, command);
592 # ifdef LOGIN_NEEDS_UTMPX
598 /* Do common processing for the child, such as execing the command. */
599 do_child(s, command);
603 signal(WJSIGNAL, cray_job_termination_handler);
607 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
610 packet_disconnect("fork failed: %.100s", strerror(errno));
613 /* Parent. Close the slave side of the pseudo tty. */
617 * Create another descriptor of the pty master side for use as the
618 * standard input. We could use the original descriptor, but this
619 * simplifies code in server_loop. The descriptor is bidirectional.
623 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
625 /* we keep a reference to the pty master */
626 ptymaster = dup(ptyfd);
628 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
629 s->ptymaster = ptymaster;
631 /* Enter interactive session. */
632 packet_set_interactive(1);
634 session_set_fds(s, ptyfd, fdout, -1);
636 server_loop(pid, ptyfd, fdout, -1);
637 /* server_loop _has_ closed ptyfd and fdout. */
641 #ifdef LOGIN_NEEDS_UTMPX
643 do_pre_login(Session *s)
646 struct sockaddr_storage from;
647 pid_t pid = getpid();
650 * Get IP address of client. If the connection is not a socket, let
651 * the address be 0.0.0.0.
653 memset(&from, 0, sizeof(from));
654 fromlen = sizeof(from);
655 if (packet_connection_is_on_socket()) {
656 if (getpeername(packet_get_connection_in(),
657 (struct sockaddr *)&from, &fromlen) < 0) {
658 debug("getpeername: %.100s", strerror(errno));
663 record_utmp_only(pid, s->tty, s->pw->pw_name,
664 get_remote_name_or_ip(utmp_len, options.use_dns),
665 (struct sockaddr *)&from, fromlen);
670 * This is called to fork and execute a command. If another command is
671 * to be forced, execute that instead.
674 do_exec(Session *s, const char *command)
676 if (options.adm_forced_command) {
677 original_command = command;
678 command = options.adm_forced_command;
679 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
680 s->is_subsystem = SUBSYSTEM_INT_SFTP;
681 else if (s->is_subsystem)
682 s->is_subsystem = SUBSYSTEM_EXT;
683 debug("Forced command (config) '%.900s'", command);
684 } else if (forced_command) {
685 original_command = command;
686 command = forced_command;
687 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
688 s->is_subsystem = SUBSYSTEM_INT_SFTP;
689 else if (s->is_subsystem)
690 s->is_subsystem = SUBSYSTEM_EXT;
691 debug("Forced command (key option) '%.900s'", command);
694 #ifdef SSH_AUDIT_EVENTS
696 PRIVSEP(audit_run_command(command));
697 else if (s->ttyfd == -1) {
698 char *shell = s->pw->pw_shell;
700 if (shell[0] == '\0') /* empty shell means /bin/sh */
702 PRIVSEP(audit_run_command(shell));
706 do_exec_pty(s, command);
708 do_exec_no_pty(s, command);
710 original_command = NULL;
713 * Clear loginmsg: it's the child's responsibility to display
714 * it to the user, otherwise multiple sessions may accumulate
715 * multiple copies of the login messages.
717 buffer_clear(&loginmsg);
720 /* administrative, login(1)-like work */
722 do_login(Session *s, const char *command)
725 struct sockaddr_storage from;
726 struct passwd * pw = s->pw;
727 pid_t pid = getpid();
730 * Get IP address of client. If the connection is not a socket, let
731 * the address be 0.0.0.0.
733 memset(&from, 0, sizeof(from));
734 fromlen = sizeof(from);
735 if (packet_connection_is_on_socket()) {
736 if (getpeername(packet_get_connection_in(),
737 (struct sockaddr *) & from, &fromlen) < 0) {
738 debug("getpeername: %.100s", strerror(errno));
743 /* Record that there was a login on that tty from the remote host. */
745 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
746 get_remote_name_or_ip(utmp_len,
748 (struct sockaddr *)&from, fromlen);
752 * If password change is needed, do it now.
753 * This needs to occur before the ~/.hushlogin check.
755 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
758 s->authctxt->force_pwchange = 0;
759 /* XXX - signal [net] parent to enable forwardings */
763 if (check_quietlogin(s, command))
772 * Display the message of the day.
780 if (options.print_motd) {
781 #ifdef HAVE_LOGIN_CAP
782 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
785 f = fopen("/etc/motd", "r");
788 while (fgets(buf, sizeof(buf), f))
797 * Check for quiet login, either .hushlogin or command given.
800 check_quietlogin(Session *s, const char *command)
803 struct passwd *pw = s->pw;
806 /* Return 1 if .hushlogin exists or a command given. */
809 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
810 #ifdef HAVE_LOGIN_CAP
811 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
814 if (stat(buf, &st) >= 0)
821 * Sets the value of the given variable in the environment. If the variable
822 * already exists, its value is overriden.
825 child_set_env(char ***envp, u_int *envsizep, const char *name,
833 * If we're passed an uninitialized list, allocate a single null
834 * entry before continuing.
836 if (*envp == NULL && *envsizep == 0) {
837 *envp = xmalloc(sizeof(char *));
843 * Find the slot where the value should be stored. If the variable
844 * already exists, we reuse the slot; otherwise we append a new slot
845 * at the end of the array, expanding if necessary.
848 namelen = strlen(name);
849 for (i = 0; env[i]; i++)
850 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
853 /* Reuse the slot. */
856 /* New variable. Expand if necessary. */
858 if (i >= envsize - 1) {
860 fatal("child_set_env: too many env vars");
862 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
865 /* Need to set the NULL pointer at end of array beyond the new slot. */
869 /* Allocate space and format the variable in the appropriate slot. */
870 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
871 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
875 * Reads environment variables from the given file and adds/overrides them
876 * into the environment. If the file does not exist, this does nothing.
877 * Otherwise, it must consist of empty lines, comments (line starts with '#')
878 * and assignments of the form name=value. No other forms are allowed.
881 read_environment_file(char ***env, u_int *envsize,
882 const char *filename)
889 f = fopen(filename, "r");
893 while (fgets(buf, sizeof(buf), f)) {
895 fatal("Too many lines in environment file %s", filename);
896 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
898 if (!*cp || *cp == '#' || *cp == '\n')
901 cp[strcspn(cp, "\n")] = '\0';
903 value = strchr(cp, '=');
905 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
910 * Replace the equals sign by nul, and advance value to
915 child_set_env(env, envsize, cp, value);
920 #ifdef HAVE_ETC_DEFAULT_LOGIN
922 * Return named variable from specified environment, or NULL if not present.
925 child_get_env(char **env, const char *name)
931 for (i=0; env[i] != NULL; i++)
932 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
933 return(env[i] + len + 1);
938 * Read /etc/default/login.
939 * We pick up the PATH (or SUPATH for root) and UMASK.
942 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
944 char **tmpenv = NULL, *var;
945 u_int i, tmpenvsize = 0;
949 * We don't want to copy the whole file to the child's environment,
950 * so we use a temporary environment and copy the variables we're
953 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
959 var = child_get_env(tmpenv, "SUPATH");
961 var = child_get_env(tmpenv, "PATH");
963 child_set_env(env, envsize, "PATH", var);
965 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
966 if (sscanf(var, "%5lo", &mask) == 1)
969 for (i = 0; tmpenv[i] != NULL; i++)
973 #endif /* HAVE_ETC_DEFAULT_LOGIN */
976 copy_environment(char **source, char ***env, u_int *envsize)
978 char *var_name, *var_val;
984 for(i = 0; source[i] != NULL; i++) {
985 var_name = xstrdup(source[i]);
986 if ((var_val = strstr(var_name, "=")) == NULL) {
992 debug3("Copy environment: %s=%s", var_name, var_val);
993 child_set_env(env, envsize, var_name, var_val);
1000 do_setup_env(Session *s, const char *shell)
1005 struct passwd *pw = s->pw;
1006 #ifndef HAVE_LOGIN_CAP
1010 /* Initialize the environment. */
1012 env = xcalloc(envsize, sizeof(char *));
1017 * The Windows environment contains some setting which are
1018 * important for a running system. They must not be dropped.
1023 p = fetch_windows_environment();
1024 copy_environment(p, &env, &envsize);
1025 free_windows_environment(p);
1030 /* Allow any GSSAPI methods that we've used to alter
1031 * the childs environment as they see fit
1033 ssh_gssapi_do_child(&env, &envsize);
1036 if (!options.use_login) {
1037 /* Set basic environment. */
1038 for (i = 0; i < s->num_env; i++)
1039 child_set_env(&env, &envsize, s->env[i].name,
1042 child_set_env(&env, &envsize, "USER", pw->pw_name);
1043 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1045 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1047 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1048 #ifdef HAVE_LOGIN_CAP
1049 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1050 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1052 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1053 #else /* HAVE_LOGIN_CAP */
1054 # ifndef HAVE_CYGWIN
1056 * There's no standard path on Windows. The path contains
1057 * important components pointing to the system directories,
1058 * needed for loading shared libraries. So the path better
1059 * remains intact here.
1061 # ifdef HAVE_ETC_DEFAULT_LOGIN
1062 read_etc_default_login(&env, &envsize, pw->pw_uid);
1063 path = child_get_env(env, "PATH");
1064 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1065 if (path == NULL || *path == '\0') {
1066 child_set_env(&env, &envsize, "PATH",
1067 s->pw->pw_uid == 0 ?
1068 SUPERUSER_PATH : _PATH_STDPATH);
1070 # endif /* HAVE_CYGWIN */
1071 #endif /* HAVE_LOGIN_CAP */
1073 snprintf(buf, sizeof buf, "%.200s/%.50s",
1074 _PATH_MAILDIR, pw->pw_name);
1075 child_set_env(&env, &envsize, "MAIL", buf);
1077 /* Normal systems set SHELL by default. */
1078 child_set_env(&env, &envsize, "SHELL", shell);
1081 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1083 /* Set custom environment options from RSA authentication. */
1084 if (!options.use_login) {
1085 while (custom_environment) {
1086 struct envstring *ce = custom_environment;
1089 for (i = 0; str[i] != '=' && str[i]; i++)
1091 if (str[i] == '=') {
1093 child_set_env(&env, &envsize, str, str + i + 1);
1095 custom_environment = ce->next;
1101 /* SSH_CLIENT deprecated */
1102 snprintf(buf, sizeof buf, "%.50s %d %d",
1103 get_remote_ipaddr(), get_remote_port(), get_local_port());
1104 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1106 laddr = get_local_ipaddr(packet_get_connection_in());
1107 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1108 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1110 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1113 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1115 child_set_env(&env, &envsize, "TERM", s->term);
1117 child_set_env(&env, &envsize, "DISPLAY", s->display);
1118 if (original_command)
1119 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1123 if (cray_tmpdir[0] != '\0')
1124 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1125 #endif /* _UNICOS */
1128 * Since we clear KRB5CCNAME at startup, if it's set now then it
1129 * must have been set by a native authentication method (eg AIX or
1130 * SIA), so copy it to the child.
1135 if ((cp = getenv("KRB5CCNAME")) != NULL)
1136 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1143 if ((cp = getenv("AUTHSTATE")) != NULL)
1144 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1145 read_environment_file(&env, &envsize, "/etc/environment");
1149 if (s->authctxt->krb5_ccname)
1150 child_set_env(&env, &envsize, "KRB5CCNAME",
1151 s->authctxt->krb5_ccname);
1155 * Pull in any environment variables that may have
1158 if (options.use_pam) {
1161 p = fetch_pam_child_environment();
1162 copy_environment(p, &env, &envsize);
1163 free_pam_environment(p);
1165 p = fetch_pam_environment();
1166 copy_environment(p, &env, &envsize);
1167 free_pam_environment(p);
1169 #endif /* USE_PAM */
1171 if (auth_sock_name != NULL)
1172 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1175 /* read $HOME/.ssh/environment. */
1176 if (options.permit_user_env && !options.use_login) {
1177 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1178 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1179 read_environment_file(&env, &envsize, buf);
1182 /* dump the environment */
1183 fprintf(stderr, "Environment:\n");
1184 for (i = 0; env[i]; i++)
1185 fprintf(stderr, " %.200s\n", env[i]);
1191 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1192 * first in this order).
1195 do_rc_files(Session *s, const char *shell)
1203 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1205 /* ignore _PATH_SSH_USER_RC for subsystems */
1206 if (!s->is_subsystem && (stat(_PATH_SSH_USER_RC, &st) >= 0)) {
1207 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1208 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1210 fprintf(stderr, "Running %s\n", cmd);
1211 f = popen(cmd, "w");
1214 fprintf(f, "%s %s\n", s->auth_proto,
1218 fprintf(stderr, "Could not run %s\n",
1220 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1222 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1223 _PATH_SSH_SYSTEM_RC);
1224 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1227 fprintf(f, "%s %s\n", s->auth_proto,
1231 fprintf(stderr, "Could not run %s\n",
1232 _PATH_SSH_SYSTEM_RC);
1233 } else if (do_xauth && options.xauth_location != NULL) {
1234 /* Add authority data to .Xauthority if appropriate. */
1237 "Running %.500s remove %.100s\n",
1238 options.xauth_location, s->auth_display);
1240 "%.500s add %.100s %.100s %.100s\n",
1241 options.xauth_location, s->auth_display,
1242 s->auth_proto, s->auth_data);
1244 snprintf(cmd, sizeof cmd, "%s -q -",
1245 options.xauth_location);
1246 f = popen(cmd, "w");
1248 fprintf(f, "remove %s\n",
1250 fprintf(f, "add %s %s %s\n",
1251 s->auth_display, s->auth_proto,
1255 fprintf(stderr, "Could not run %s\n",
1262 do_nologin(struct passwd *pw)
1267 #ifdef HAVE_LOGIN_CAP
1268 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1269 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1270 _PATH_NOLOGIN), "r");
1273 f = fopen(_PATH_NOLOGIN, "r");
1276 /* /etc/nologin exists. Print its contents and exit. */
1277 logit("User %.100s not allowed because %s exists",
1278 pw->pw_name, _PATH_NOLOGIN);
1279 while (fgets(buf, sizeof(buf), f))
1288 * Chroot into a directory after checking it for safety: all path components
1289 * must be root-owned directories with strict permissions.
1292 safely_chroot(const char *path, uid_t uid)
1295 char component[MAXPATHLEN];
1299 fatal("chroot path does not begin at root");
1300 if (strlen(path) >= sizeof(component))
1301 fatal("chroot path too long");
1304 * Descend the path, checking that each component is a
1305 * root-owned directory with strict permissions.
1307 for (cp = path; cp != NULL;) {
1308 if ((cp = strchr(cp, '/')) == NULL)
1309 strlcpy(component, path, sizeof(component));
1312 memcpy(component, path, cp - path);
1313 component[cp - path] = '\0';
1316 debug3("%s: checking '%s'", __func__, component);
1318 if (stat(component, &st) != 0)
1319 fatal("%s: stat(\"%s\"): %s", __func__,
1320 component, strerror(errno));
1321 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1322 fatal("bad ownership or modes for chroot "
1323 "directory %s\"%s\"",
1324 cp == NULL ? "" : "component ", component);
1325 if (!S_ISDIR(st.st_mode))
1326 fatal("chroot path %s\"%s\" is not a directory",
1327 cp == NULL ? "" : "component ", component);
1331 if (chdir(path) == -1)
1332 fatal("Unable to chdir to chroot path \"%s\": "
1333 "%s", path, strerror(errno));
1334 if (chroot(path) == -1)
1335 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1336 if (chdir("/") == -1)
1337 fatal("%s: chdir(/) after chroot: %s",
1338 __func__, strerror(errno));
1339 verbose("Changed root directory to \"%s\"", path);
1342 /* Set login name, uid, gid, and groups. */
1344 do_setusercontext(struct passwd *pw)
1346 char *chroot_path, *tmp;
1349 if (getuid() == 0 || geteuid() == 0)
1350 #endif /* HAVE_CYGWIN */
1353 #ifdef HAVE_SETPCRED
1354 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1355 fatal("Failed to set process credentials");
1356 #endif /* HAVE_SETPCRED */
1357 #ifdef HAVE_LOGIN_CAP
1362 if (options.use_pam) {
1363 do_pam_setcred(use_privsep);
1365 # endif /* USE_PAM */
1366 if (setusercontext(lc, pw, pw->pw_uid,
1367 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1368 perror("unable to set user context");
1372 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1373 /* Sets login uid for accounting */
1374 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1375 error("setluid: %s", strerror(errno));
1376 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1378 if (setlogin(pw->pw_name) < 0)
1379 error("setlogin failed: %s", strerror(errno));
1380 if (setgid(pw->pw_gid) < 0) {
1384 /* Initialize the group list. */
1385 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1386 perror("initgroups");
1392 * PAM credentials may take the form of supplementary groups.
1393 * These will have been wiped by the above initgroups() call.
1394 * Reestablish them here.
1396 if (options.use_pam) {
1397 do_pam_setcred(use_privsep);
1399 # endif /* USE_PAM */
1400 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1401 irix_setusercontext(pw);
1402 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1407 if (set_id(pw->pw_name) != 0) {
1410 # endif /* USE_LIBIAF */
1413 if (options.chroot_directory != NULL &&
1414 strcasecmp(options.chroot_directory, "none") != 0) {
1415 tmp = tilde_expand_filename(options.chroot_directory,
1417 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1418 "u", pw->pw_name, (char *)NULL);
1419 safely_chroot(chroot_path, pw->pw_uid);
1424 #ifdef HAVE_LOGIN_CAP
1425 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1426 perror("unable to set user context (setuser)");
1430 /* Permanently switch to the desired uid. */
1431 permanently_set_uid(pw);
1438 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1439 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1442 ssh_selinux_setup_exec_context(pw->pw_name);
1447 do_pwchange(Session *s)
1450 fprintf(stderr, "WARNING: Your password has expired.\n");
1451 if (s->ttyfd != -1) {
1453 "You must change your password now and login again!\n");
1454 #ifdef PASSWD_NEEDS_USERNAME
1455 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1458 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1463 "Password change required but no TTY available.\n");
1469 launch_login(struct passwd *pw, const char *hostname)
1471 /* Launch login(1). */
1473 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1474 #ifdef xxxLOGIN_NEEDS_TERM
1475 (s->term ? s->term : "unknown"),
1476 #endif /* LOGIN_NEEDS_TERM */
1477 #ifdef LOGIN_NO_ENDOPT
1478 "-p", "-f", pw->pw_name, (char *)NULL);
1480 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1483 /* Login couldn't be executed, die. */
1490 child_close_fds(void)
1494 if (packet_get_connection_in() == packet_get_connection_out())
1495 close(packet_get_connection_in());
1497 close(packet_get_connection_in());
1498 close(packet_get_connection_out());
1501 * Close all descriptors related to channels. They will still remain
1502 * open in the parent.
1504 /* XXX better use close-on-exec? -markus */
1505 channel_close_all();
1508 * Close any extra file descriptors. Note that there may still be
1509 * descriptors left by system functions. They will be closed later.
1514 * Close any extra open file descriptors so that we don't have them
1515 * hanging around in clients. Note that we want to do this after
1516 * initgroups, because at least on Solaris 2.3 it leaves file
1519 for (i = 3; i < 64; i++)
1524 * Performs common processing for the child, such as setting up the
1525 * environment, closing extra file descriptors, setting the user and group
1526 * ids, and executing the command or shell.
1530 do_child(Session *s, const char *command)
1532 extern char **environ;
1534 char *argv[ARGV_MAX];
1535 const char *shell, *shell0, *hostname = NULL;
1536 struct passwd *pw = s->pw;
1538 /* remove hostkey from the child's memory */
1539 destroy_sensitive_data();
1541 /* Force a password change */
1542 if (s->authctxt->force_pwchange) {
1543 do_setusercontext(pw);
1549 /* login(1) is only called if we execute the login shell */
1550 if (options.use_login && command != NULL)
1551 options.use_login = 0;
1554 cray_setup(pw->pw_uid, pw->pw_name, command);
1555 #endif /* _UNICOS */
1558 * Login(1) does this as well, and it needs uid 0 for the "-h"
1559 * switch, so we let login(1) to this for us.
1561 if (!options.use_login) {
1563 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1564 if (!check_quietlogin(s, command))
1566 #else /* HAVE_OSF_SIA */
1567 /* When PAM is enabled we rely on it to do the nologin check */
1568 if (!options.use_pam)
1570 do_setusercontext(pw);
1572 * PAM session modules in do_setusercontext may have
1573 * generated messages, so if this in an interactive
1574 * login then display them too.
1576 if (!check_quietlogin(s, command))
1578 #endif /* HAVE_OSF_SIA */
1582 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1583 debug3("PAM session not opened, exiting");
1590 * Get the shell from the password data. An empty shell field is
1591 * legal, and means /bin/sh.
1593 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1596 * Make sure $SHELL points to the shell from the password file,
1597 * even if shell is overridden from login.conf
1599 env = do_setup_env(s, shell);
1601 #ifdef HAVE_LOGIN_CAP
1602 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1605 /* we have to stash the hostname before we close our socket. */
1606 if (options.use_login)
1607 hostname = get_remote_name_or_ip(utmp_len,
1610 * Close the connection descriptors; note that this is the child, and
1611 * the server will still have the socket open, and it is important
1612 * that we do not shutdown it. Note that the descriptors cannot be
1613 * closed before building the environment, as we call
1614 * get_remote_ipaddr there.
1619 * Must take new environment into use so that .ssh/rc,
1620 * /etc/ssh/sshrc and xauth are run in the proper environment.
1624 #if defined(KRB5) && defined(USE_AFS)
1626 * At this point, we check to see if AFS is active and if we have
1627 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1628 * if we can (and need to) extend the ticket into an AFS token. If
1629 * we don't do this, we run into potential problems if the user's
1630 * home directory is in AFS and it's not world-readable.
1633 if (options.kerberos_get_afs_token && k_hasafs() &&
1634 (s->authctxt->krb5_ctx != NULL)) {
1637 debug("Getting AFS token");
1641 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1642 krb5_afslog(s->authctxt->krb5_ctx,
1643 s->authctxt->krb5_fwd_ccache, cell, NULL);
1645 krb5_afslog_home(s->authctxt->krb5_ctx,
1646 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1650 /* Change current directory to the user's home directory. */
1651 if (chdir(pw->pw_dir) < 0) {
1652 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1653 pw->pw_dir, strerror(errno));
1654 #ifdef HAVE_LOGIN_CAP
1655 if (login_getcapbool(lc, "requirehome", 0))
1660 closefrom(STDERR_FILENO + 1);
1662 if (!options.use_login)
1663 do_rc_files(s, shell);
1665 /* restore SIGPIPE for child */
1666 signal(SIGPIPE, SIG_DFL);
1668 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1669 extern int optind, optreset;
1673 setproctitle("%s@internal-sftp-server", s->pw->pw_name);
1674 args = strdup(command ? command : "sftp-server");
1675 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1676 if (i < ARGV_MAX - 1)
1679 optind = optreset = 1;
1680 __progname = argv[0];
1681 exit(sftp_server_main(i, argv, s->pw));
1684 if (options.use_login) {
1685 launch_login(pw, hostname);
1689 /* Get the last component of the shell name. */
1690 if ((shell0 = strrchr(shell, '/')) != NULL)
1696 * If we have no command, execute the shell. In this case, the shell
1697 * name to be passed in argv[0] is preceded by '-' to indicate that
1698 * this is a login shell.
1703 /* Start the shell. Set initial character to '-'. */
1706 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1707 >= sizeof(argv0) - 1) {
1713 /* Execute the shell. */
1716 execve(shell, argv, env);
1718 /* Executing the shell failed. */
1723 * Execute the command using the user's shell. This uses the -c
1724 * option to execute the command.
1726 argv[0] = (char *) shell0;
1728 argv[2] = (char *) command;
1730 execve(shell, argv, env);
1739 static int did_init = 0;
1741 debug("session_new: init");
1742 for (i = 0; i < MAX_SESSIONS; i++) {
1743 sessions[i].used = 0;
1747 for (i = 0; i < MAX_SESSIONS; i++) {
1748 Session *s = &sessions[i];
1750 memset(s, 0, sizeof(*s));
1756 s->x11_chanids = NULL;
1757 debug("session_new: session %d", i);
1768 for (i = 0; i < MAX_SESSIONS; i++) {
1769 Session *s = &sessions[i];
1770 debug("dump: used %d session %d %p channel %d pid %ld",
1780 session_open(Authctxt *authctxt, int chanid)
1782 Session *s = session_new();
1783 debug("session_open: channel %d", chanid);
1785 error("no more sessions");
1788 s->authctxt = authctxt;
1789 s->pw = authctxt->pw;
1790 if (s->pw == NULL || !authctxt->valid)
1791 fatal("no user for session %d", s->self);
1792 debug("session_open: session %d: link with channel %d", s->self, chanid);
1798 session_by_tty(char *tty)
1801 for (i = 0; i < MAX_SESSIONS; i++) {
1802 Session *s = &sessions[i];
1803 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1804 debug("session_by_tty: session %d tty %s", i, tty);
1808 debug("session_by_tty: unknown tty %.100s", tty);
1814 session_by_channel(int id)
1817 for (i = 0; i < MAX_SESSIONS; i++) {
1818 Session *s = &sessions[i];
1819 if (s->used && s->chanid == id) {
1820 debug("session_by_channel: session %d channel %d", i, id);
1824 debug("session_by_channel: unknown channel %d", id);
1830 session_by_x11_channel(int id)
1834 for (i = 0; i < MAX_SESSIONS; i++) {
1835 Session *s = &sessions[i];
1837 if (s->x11_chanids == NULL || !s->used)
1839 for (j = 0; s->x11_chanids[j] != -1; j++) {
1840 if (s->x11_chanids[j] == id) {
1841 debug("session_by_x11_channel: session %d "
1842 "channel %d", s->self, id);
1847 debug("session_by_x11_channel: unknown channel %d", id);
1853 session_by_pid(pid_t pid)
1856 debug("session_by_pid: pid %ld", (long)pid);
1857 for (i = 0; i < MAX_SESSIONS; i++) {
1858 Session *s = &sessions[i];
1859 if (s->used && s->pid == pid)
1862 error("session_by_pid: unknown pid %ld", (long)pid);
1868 session_window_change_req(Session *s)
1870 s->col = packet_get_int();
1871 s->row = packet_get_int();
1872 s->xpixel = packet_get_int();
1873 s->ypixel = packet_get_int();
1875 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1880 session_pty_req(Session *s)
1886 debug("Allocating a pty not permitted for this authentication.");
1889 if (s->ttyfd != -1) {
1890 packet_disconnect("Protocol error: you already have a pty.");
1894 s->term = packet_get_string(&len);
1897 s->col = packet_get_int();
1898 s->row = packet_get_int();
1900 s->row = packet_get_int();
1901 s->col = packet_get_int();
1903 s->xpixel = packet_get_int();
1904 s->ypixel = packet_get_int();
1906 if (strcmp(s->term, "") == 0) {
1911 /* Allocate a pty and open it. */
1912 debug("Allocating pty.");
1913 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1919 error("session_pty_req: session %d alloc failed", s->self);
1922 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1924 /* for SSH1 the tty modes length is not given */
1926 n_bytes = packet_remaining();
1927 tty_parse_modes(s->ttyfd, &n_bytes);
1930 pty_setowner(s->pw, s->tty);
1932 /* Set window size from the packet. */
1933 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1936 session_proctitle(s);
1941 session_subsystem_req(Session *s)
1946 char *prog, *cmd, *subsys = packet_get_string(&len);
1950 logit("subsystem request for %.100s", subsys);
1952 for (i = 0; i < options.num_subsystems; i++) {
1953 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1954 prog = options.subsystem_command[i];
1955 cmd = options.subsystem_args[i];
1956 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
1957 s->is_subsystem = SUBSYSTEM_INT_SFTP;
1958 } else if (stat(prog, &st) < 0) {
1959 error("subsystem: cannot stat %s: %s", prog,
1963 s->is_subsystem = SUBSYSTEM_EXT;
1965 debug("subsystem: exec() %s", cmd);
1973 logit("subsystem request for %.100s failed, subsystem not found",
1981 session_x11_req(Session *s)
1985 if (s->auth_proto != NULL || s->auth_data != NULL) {
1986 error("session_x11_req: session %d: "
1987 "x11 forwarding already active", s->self);
1990 s->single_connection = packet_get_char();
1991 s->auth_proto = packet_get_string(NULL);
1992 s->auth_data = packet_get_string(NULL);
1993 s->screen = packet_get_int();
1996 success = session_setup_x11fwd(s);
1998 xfree(s->auth_proto);
1999 xfree(s->auth_data);
2000 s->auth_proto = NULL;
2001 s->auth_data = NULL;
2007 session_shell_req(Session *s)
2015 session_exec_req(Session *s)
2018 char *command = packet_get_string(&len);
2020 do_exec(s, command);
2026 session_break_req(Session *s)
2029 packet_get_int(); /* ignored */
2032 if (s->ttyfd == -1 ||
2033 tcsendbreak(s->ttyfd, 0) < 0)
2039 session_env_req(Session *s)
2042 u_int name_len, val_len, i;
2044 name = packet_get_string(&name_len);
2045 val = packet_get_string(&val_len);
2048 /* Don't set too many environment variables */
2049 if (s->num_env > 128) {
2050 debug2("Ignoring env request %s: too many env vars", name);
2054 for (i = 0; i < options.num_accept_env; i++) {
2055 if (match_pattern(name, options.accept_env[i])) {
2056 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2057 s->env = xrealloc(s->env, s->num_env + 1,
2059 s->env[s->num_env].name = name;
2060 s->env[s->num_env].val = val;
2065 debug2("Ignoring env request %s: disallowed name", name);
2074 session_auth_agent_req(Session *s)
2076 static int called = 0;
2078 if (no_agent_forwarding_flag) {
2079 debug("session_auth_agent_req: no_agent_forwarding_flag");
2086 return auth_input_request_forwarding(s->pw);
2091 session_input_channel_req(Channel *c, const char *rtype)
2096 if ((s = session_by_channel(c->self)) == NULL) {
2097 logit("session_input_channel_req: no session %d req %.100s",
2101 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2104 * a session is in LARVAL state until a shell, a command
2105 * or a subsystem is executed
2107 if (c->type == SSH_CHANNEL_LARVAL) {
2108 if (strcmp(rtype, "shell") == 0) {
2109 success = session_shell_req(s);
2110 } else if (strcmp(rtype, "exec") == 0) {
2111 success = session_exec_req(s);
2112 } else if (strcmp(rtype, "pty-req") == 0) {
2113 success = session_pty_req(s);
2114 } else if (strcmp(rtype, "x11-req") == 0) {
2115 success = session_x11_req(s);
2116 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2117 success = session_auth_agent_req(s);
2118 } else if (strcmp(rtype, "subsystem") == 0) {
2119 success = session_subsystem_req(s);
2120 } else if (strcmp(rtype, "env") == 0) {
2121 success = session_env_req(s);
2124 if (strcmp(rtype, "window-change") == 0) {
2125 success = session_window_change_req(s);
2126 } else if (strcmp(rtype, "break") == 0) {
2127 success = session_break_req(s);
2134 session_set_fds(Session *s, int fdin, int fdout, int fderr)
2137 fatal("session_set_fds: called for proto != 2.0");
2139 * now that have a child and a pipe to the child,
2140 * we can activate our channel and register the fd's
2142 if (s->chanid == -1)
2143 fatal("no channel for session %d", s->self);
2144 channel_set_fds(s->chanid,
2146 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2148 CHAN_SES_WINDOW_DEFAULT);
2152 * Function to perform pty cleanup. Also called if we get aborted abnormally
2153 * (e.g., due to a dropped connection).
2156 session_pty_cleanup2(Session *s)
2159 error("session_pty_cleanup: no session");
2165 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2167 /* Record that the user has logged out. */
2169 record_logout(s->pid, s->tty, s->pw->pw_name);
2171 /* Release the pseudo-tty. */
2173 pty_release(s->tty);
2176 * Close the server side of the socket pairs. We must do this after
2177 * the pty cleanup, so that another process doesn't get this pty
2178 * while we're still cleaning up.
2180 if (close(s->ptymaster) < 0)
2181 error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
2183 /* unlink pty from session */
2188 session_pty_cleanup(Session *s)
2190 PRIVSEP(session_pty_cleanup2(s));
2196 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2211 return "SIG@openssh.com";
2215 session_close_x11(int id)
2219 if ((c = channel_by_id(id)) == NULL) {
2220 debug("session_close_x11: x11 channel %d missing", id);
2222 /* Detach X11 listener */
2223 debug("session_close_x11: detach x11 channel %d", id);
2224 channel_cancel_cleanup(id);
2225 if (c->ostate != CHAN_OUTPUT_CLOSED)
2231 session_close_single_x11(int id, void *arg)
2236 debug3("session_close_single_x11: channel %d", id);
2237 channel_cancel_cleanup(id);
2238 if ((s = session_by_x11_channel(id)) == NULL)
2239 fatal("session_close_single_x11: no x11 channel %d", id);
2240 for (i = 0; s->x11_chanids[i] != -1; i++) {
2241 debug("session_close_single_x11: session %d: "
2242 "closing channel %d", s->self, s->x11_chanids[i]);
2244 * The channel "id" is already closing, but make sure we
2245 * close all of its siblings.
2247 if (s->x11_chanids[i] != id)
2248 session_close_x11(s->x11_chanids[i]);
2250 xfree(s->x11_chanids);
2251 s->x11_chanids = NULL;
2256 if (s->auth_proto) {
2257 xfree(s->auth_proto);
2258 s->auth_proto = NULL;
2261 xfree(s->auth_data);
2262 s->auth_data = NULL;
2264 if (s->auth_display) {
2265 xfree(s->auth_display);
2266 s->auth_display = NULL;
2271 session_exit_message(Session *s, int status)
2275 if ((c = channel_lookup(s->chanid)) == NULL)
2276 fatal("session_exit_message: session %d: no channel %d",
2277 s->self, s->chanid);
2278 debug("session_exit_message: session %d channel %d pid %ld",
2279 s->self, s->chanid, (long)s->pid);
2281 if (WIFEXITED(status)) {
2282 channel_request_start(s->chanid, "exit-status", 0);
2283 packet_put_int(WEXITSTATUS(status));
2285 } else if (WIFSIGNALED(status)) {
2286 channel_request_start(s->chanid, "exit-signal", 0);
2287 packet_put_cstring(sig2name(WTERMSIG(status)));
2289 packet_put_char(WCOREDUMP(status)? 1 : 0);
2290 #else /* WCOREDUMP */
2292 #endif /* WCOREDUMP */
2293 packet_put_cstring("");
2294 packet_put_cstring("");
2297 /* Some weird exit cause. Just exit. */
2298 packet_disconnect("wait returned status %04x.", status);
2301 /* disconnect channel */
2302 debug("session_exit_message: release channel %d", s->chanid);
2305 * Adjust cleanup callback attachment to send close messages when
2306 * the channel gets EOF. The session will be then be closed
2307 * by session_close_by_channel when the childs close their fds.
2309 channel_register_cleanup(c->self, session_close_by_channel, 1);
2312 * emulate a write failure with 'chan_write_failed', nobody will be
2313 * interested in data we write.
2314 * Note that we must not call 'chan_read_failed', since there could
2315 * be some more data waiting in the pipe.
2317 if (c->ostate != CHAN_OUTPUT_CLOSED)
2318 chan_write_failed(c);
2322 session_close(Session *s)
2326 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2328 session_pty_cleanup(s);
2334 xfree(s->x11_chanids);
2335 if (s->auth_display)
2336 xfree(s->auth_display);
2338 xfree(s->auth_data);
2340 xfree(s->auth_proto);
2342 if (s->env != NULL) {
2343 for (i = 0; i < s->num_env; i++) {
2344 xfree(s->env[i].name);
2345 xfree(s->env[i].val);
2349 session_proctitle(s);
2353 session_close_by_pid(pid_t pid, int status)
2355 Session *s = session_by_pid(pid);
2357 debug("session_close_by_pid: no session for pid %ld",
2361 if (s->chanid != -1)
2362 session_exit_message(s, status);
2364 session_pty_cleanup(s);
2369 * this is called when a channel dies before
2370 * the session 'child' itself dies
2373 session_close_by_channel(int id, void *arg)
2375 Session *s = session_by_channel(id);
2379 debug("session_close_by_channel: no session for id %d", id);
2382 debug("session_close_by_channel: channel %d child %ld",
2385 debug("session_close_by_channel: channel %d: has child", id);
2387 * delay detach of session, but release pty, since
2388 * the fd's to the child are already closed
2391 session_pty_cleanup(s);
2394 /* detach by removing callback */
2395 channel_cancel_cleanup(s->chanid);
2397 /* Close any X11 listeners associated with this session */
2398 if (s->x11_chanids != NULL) {
2399 for (i = 0; s->x11_chanids[i] != -1; i++) {
2400 session_close_x11(s->x11_chanids[i]);
2401 s->x11_chanids[i] = -1;
2410 session_destroy_all(void (*closefunc)(Session *))
2413 for (i = 0; i < MAX_SESSIONS; i++) {
2414 Session *s = &sessions[i];
2416 if (closefunc != NULL)
2425 session_tty_list(void)
2427 static char buf[1024];
2432 for (i = 0; i < MAX_SESSIONS; i++) {
2433 Session *s = &sessions[i];
2434 if (s->used && s->ttyfd != -1) {
2436 if (strncmp(s->tty, "/dev/", 5) != 0) {
2437 cp = strrchr(s->tty, '/');
2438 cp = (cp == NULL) ? s->tty : cp + 1;
2443 strlcat(buf, ",", sizeof buf);
2444 strlcat(buf, cp, sizeof buf);
2448 strlcpy(buf, "notty", sizeof buf);
2453 session_proctitle(Session *s)
2456 error("no user for session %d", s->self);
2458 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2462 session_setup_x11fwd(Session *s)
2465 char display[512], auth_display[512];
2466 char hostname[MAXHOSTNAMELEN];
2469 if (no_x11_forwarding_flag) {
2470 packet_send_debug("X11 forwarding disabled in user configuration file.");
2473 if (!options.x11_forwarding) {
2474 debug("X11 forwarding disabled in server configuration file.");
2477 if (!options.xauth_location ||
2478 (stat(options.xauth_location, &st) == -1)) {
2479 packet_send_debug("No xauth program; cannot forward with spoofing.");
2482 if (options.use_login) {
2483 packet_send_debug("X11 forwarding disabled; "
2484 "not compatible with UseLogin=yes.");
2487 if (s->display != NULL) {
2488 debug("X11 display already set.");
2491 if (x11_create_display_inet(options.x11_display_offset,
2492 options.x11_use_localhost, s->single_connection,
2493 &s->display_number, &s->x11_chanids) == -1) {
2494 debug("x11_create_display_inet failed.");
2497 for (i = 0; s->x11_chanids[i] != -1; i++) {
2498 channel_register_cleanup(s->x11_chanids[i],
2499 session_close_single_x11, 0);
2502 /* Set up a suitable value for the DISPLAY variable. */
2503 if (gethostname(hostname, sizeof(hostname)) < 0)
2504 fatal("gethostname: %.100s", strerror(errno));
2506 * auth_display must be used as the displayname when the
2507 * authorization entry is added with xauth(1). This will be
2508 * different than the DISPLAY string for localhost displays.
2510 if (options.x11_use_localhost) {
2511 snprintf(display, sizeof display, "localhost:%u.%u",
2512 s->display_number, s->screen);
2513 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2514 s->display_number, s->screen);
2515 s->display = xstrdup(display);
2516 s->auth_display = xstrdup(auth_display);
2518 #ifdef IPADDR_IN_DISPLAY
2520 struct in_addr my_addr;
2522 he = gethostbyname(hostname);
2524 error("Can't get IP address for X11 DISPLAY.");
2525 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2528 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2529 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2530 s->display_number, s->screen);
2532 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2533 s->display_number, s->screen);
2535 s->display = xstrdup(display);
2536 s->auth_display = xstrdup(display);
2543 do_authenticated2(Authctxt *authctxt)
2545 server_loop2(authctxt);
2549 do_cleanup(Authctxt *authctxt)
2551 static int called = 0;
2553 debug("do_cleanup");
2555 /* no cleanup if we're in the child for login shell */
2559 /* avoid double cleanup */
2564 if (authctxt == NULL)
2568 if (options.use_pam) {
2570 sshpam_thread_cleanup();
2574 if (!authctxt->authenticated)
2578 if (options.kerberos_ticket_cleanup &&
2580 krb5_cleanup_proc(authctxt);
2584 if (compat20 && options.gss_cleanup_creds)
2585 ssh_gssapi_cleanup_creds();
2588 /* remove agent socket */
2589 auth_sock_cleanup_proc(authctxt->pw);
2592 * Cleanup ptys/utmp only if privsep is disabled,
2593 * or if running in monitor.
2595 if (!use_privsep || mm_is_monitor())
2596 session_destroy_all(session_pty_cleanup2);