1 /* $OpenBSD: session.c,v 1.241 2008/06/16 13:22:53 dtucker Exp $ */
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 #include <sys/types.h>
40 #include <sys/param.h>
41 #ifdef HAVE_SYS_STAT_H
42 # include <sys/stat.h>
44 #include <sys/socket.h>
48 #include <arpa/inet.h>
63 #include "openbsd-compat/sys-queue.h"
82 #include "auth-options.h"
83 #include "pathnames.h"
87 #include "serverloop.h"
92 #include "monitor_wrap.h"
95 #if defined(KRB5) && defined(USE_AFS)
101 Session *session_new(void);
102 void session_set_fds(Session *, int, int, int, int);
103 void session_pty_cleanup(Session *);
104 void session_proctitle(Session *);
105 int session_setup_x11fwd(Session *);
106 int do_exec_pty(Session *, const char *);
107 int do_exec_no_pty(Session *, const char *);
108 int do_exec(Session *, const char *);
109 void do_login(Session *, const char *);
110 #ifdef LOGIN_NEEDS_UTMPX
111 static void do_pre_login(Session *s);
113 void do_child(Session *, const char *);
115 int check_quietlogin(Session *, const char *);
117 static void do_authenticated1(Authctxt *);
118 static void do_authenticated2(Authctxt *);
120 static int session_pty_req(Session *);
123 extern ServerOptions options;
124 extern char *__progname;
125 extern int log_stderr;
126 extern int debug_flag;
127 extern u_int utmp_len;
128 extern int startup_pipe;
129 extern void destroy_sensitive_data(void);
130 extern Buffer loginmsg;
132 /* original command from peer. */
133 const char *original_command = NULL;
136 static int sessions_first_unused = -1;
137 static int sessions_nalloc = 0;
138 static Session *sessions = NULL;
140 #define SUBSYSTEM_NONE 0
141 #define SUBSYSTEM_EXT 1
142 #define SUBSYSTEM_INT_SFTP 2
144 #ifdef HAVE_LOGIN_CAP
148 static int is_child = 0;
150 /* Name and directory of socket for authentication agent forwarding. */
151 static char *auth_sock_name = NULL;
152 static char *auth_sock_dir = NULL;
154 /* removes the agent forwarding socket */
157 auth_sock_cleanup_proc(struct passwd *pw)
159 if (auth_sock_name != NULL) {
160 temporarily_use_uid(pw);
161 unlink(auth_sock_name);
162 rmdir(auth_sock_dir);
163 auth_sock_name = NULL;
169 auth_input_request_forwarding(struct passwd * pw)
173 struct sockaddr_un sunaddr;
175 if (auth_sock_name != NULL) {
176 error("authentication forwarding requested twice.");
180 /* Temporarily drop privileged uid for mkdir/bind. */
181 temporarily_use_uid(pw);
183 /* Allocate a buffer for the socket name, and format the name. */
184 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
186 /* Create private directory for socket */
187 if (mkdtemp(auth_sock_dir) == NULL) {
188 packet_send_debug("Agent forwarding disabled: "
189 "mkdtemp() failed: %.100s", strerror(errno));
191 xfree(auth_sock_dir);
192 auth_sock_dir = NULL;
196 xasprintf(&auth_sock_name, "%s/agent.%ld",
197 auth_sock_dir, (long) getpid());
199 /* Create the socket. */
200 sock = socket(AF_UNIX, SOCK_STREAM, 0);
202 error("socket: %.100s", strerror(errno));
207 /* Bind it to the name. */
208 memset(&sunaddr, 0, sizeof(sunaddr));
209 sunaddr.sun_family = AF_UNIX;
210 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
212 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
213 error("bind: %.100s", strerror(errno));
218 /* Restore the privileged uid. */
221 /* Start listening on the socket. */
222 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
223 error("listen: %.100s", strerror(errno));
227 /* Allocate a channel for the authentication agent socket. */
228 nc = channel_new("auth socket",
229 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
230 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
231 0, "auth socket", 1);
232 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
236 if (auth_sock_name != NULL)
237 xfree(auth_sock_name);
238 if (auth_sock_dir != NULL) {
239 rmdir(auth_sock_dir);
240 xfree(auth_sock_dir);
244 auth_sock_name = NULL;
245 auth_sock_dir = NULL;
250 display_loginmsg(void)
252 if (buffer_len(&loginmsg) > 0) {
253 buffer_append(&loginmsg, "\0", 1);
254 printf("%s", (char *)buffer_ptr(&loginmsg));
255 buffer_clear(&loginmsg);
260 do_authenticated(Authctxt *authctxt)
262 setproctitle("%s", authctxt->pw->pw_name);
264 /* setup the channel layer */
265 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
266 channel_permit_all_opens();
269 do_authenticated2(authctxt);
271 do_authenticated1(authctxt);
273 do_cleanup(authctxt);
277 * Prepares for an interactive session. This is called after the user has
278 * been successfully authenticated. During this message exchange, pseudo
279 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
280 * are requested, etc.
283 do_authenticated1(Authctxt *authctxt)
287 int success, type, screen_flag;
288 int enable_compression_after_reply = 0;
289 u_int proto_len, data_len, dlen, compression_level = 0;
293 error("no more sessions");
296 s->authctxt = authctxt;
297 s->pw = authctxt->pw;
300 * We stay in this loop until the client requests to execute a shell
306 /* Get a packet from the client. */
307 type = packet_read();
309 /* Process the packet. */
311 case SSH_CMSG_REQUEST_COMPRESSION:
312 compression_level = packet_get_int();
314 if (compression_level < 1 || compression_level > 9) {
315 packet_send_debug("Received invalid compression level %d.",
319 if (options.compression == COMP_NONE) {
320 debug2("compression disabled");
323 /* Enable compression after we have responded with SUCCESS. */
324 enable_compression_after_reply = 1;
328 case SSH_CMSG_REQUEST_PTY:
329 success = session_pty_req(s);
332 case SSH_CMSG_X11_REQUEST_FORWARDING:
333 s->auth_proto = packet_get_string(&proto_len);
334 s->auth_data = packet_get_string(&data_len);
336 screen_flag = packet_get_protocol_flags() &
337 SSH_PROTOFLAG_SCREEN_NUMBER;
338 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
340 if (packet_remaining() == 4) {
342 debug2("Buggy client: "
343 "X11 screen flag missing");
344 s->screen = packet_get_int();
349 success = session_setup_x11fwd(s);
351 xfree(s->auth_proto);
353 s->auth_proto = NULL;
358 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
359 if (!options.allow_agent_forwarding ||
360 no_agent_forwarding_flag || compat13) {
361 debug("Authentication agent forwarding not permitted for this authentication.");
364 debug("Received authentication agent forwarding request.");
365 success = auth_input_request_forwarding(s->pw);
368 case SSH_CMSG_PORT_FORWARD_REQUEST:
369 if (no_port_forwarding_flag) {
370 debug("Port forwarding not permitted for this authentication.");
373 if (!options.allow_tcp_forwarding) {
374 debug("Port forwarding not permitted.");
377 debug("Received TCP/IP port forwarding request.");
378 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
379 options.gateway_ports) < 0) {
380 debug("Port forwarding failed.");
386 case SSH_CMSG_MAX_PACKET_SIZE:
387 if (packet_set_maxsize(packet_get_int()) > 0)
391 case SSH_CMSG_EXEC_SHELL:
392 case SSH_CMSG_EXEC_CMD:
393 if (type == SSH_CMSG_EXEC_CMD) {
394 command = packet_get_string(&dlen);
395 debug("Exec command '%.500s'", command);
396 if (do_exec(s, command) != 0)
398 "command execution failed");
401 if (do_exec(s, NULL) != 0)
403 "shell execution failed");
411 * Any unknown messages in this phase are ignored,
412 * and a failure message is returned.
414 logit("Unknown packet type received after authentication: %d", type);
416 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
420 /* Enable compression now that we have replied if appropriate. */
421 if (enable_compression_after_reply) {
422 enable_compression_after_reply = 0;
423 packet_start_compression(compression_level);
430 * This is called to fork and execute a command when we have no tty. This
431 * will call do_child from the child, and server_loop from the parent after
432 * setting up file descriptors and such.
435 do_exec_no_pty(Session *s, const char *command)
440 int pin[2], pout[2], perr[2];
442 /* Allocate pipes for communicating with the program. */
444 error("%s: pipe in: %.100s", __func__, strerror(errno));
447 if (pipe(pout) < 0) {
448 error("%s: pipe out: %.100s", __func__, strerror(errno));
453 if (pipe(perr) < 0) {
454 error("%s: pipe err: %.100s", __func__, strerror(errno));
462 int inout[2], err[2];
464 /* Uses socket pairs to communicate with the program. */
465 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
466 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
469 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
470 error("%s: socketpair #2: %.100s", __func__, strerror(errno));
478 fatal("do_exec_no_pty: no session");
480 session_proctitle(s);
482 /* Fork the child. */
483 switch ((pid = fork())) {
485 error("%s: fork: %.100s", __func__, strerror(errno));
503 /* Child. Reinitialize the log since the pid has changed. */
504 log_init(__progname, options.log_level,
505 options.log_facility, log_stderr);
508 * Create a new session and process group since the 4.4BSD
509 * setlogin() affects the entire process group.
512 error("setsid failed: %.100s", strerror(errno));
516 * Redirect stdin. We close the parent side of the socket
517 * pair, and make the child side the standard input.
520 if (dup2(pin[0], 0) < 0)
521 perror("dup2 stdin");
524 /* Redirect stdout. */
526 if (dup2(pout[1], 1) < 0)
527 perror("dup2 stdout");
530 /* Redirect stderr. */
532 if (dup2(perr[1], 2) < 0)
533 perror("dup2 stderr");
537 * Redirect stdin, stdout, and stderr. Stdin and stdout will
538 * use the same socket, as some programs (particularly rdist)
539 * seem to depend on it.
543 if (dup2(inout[0], 0) < 0) /* stdin */
544 perror("dup2 stdin");
545 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
546 perror("dup2 stdout");
548 if (dup2(err[0], 2) < 0) /* stderr */
549 perror("dup2 stderr");
555 cray_init_job(s->pw); /* set up cray jid and tmpdir */
558 /* Do processing for the child (exec command etc). */
559 do_child(s, command);
566 signal(WJSIGNAL, cray_job_termination_handler);
570 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
574 /* Set interactive/non-interactive mode. */
575 packet_set_interactive(s->display != NULL);
578 * Clear loginmsg, since it's the child's responsibility to display
579 * it to the user, otherwise multiple sessions may accumulate
580 * multiple copies of the login messages.
582 buffer_clear(&loginmsg);
585 /* We are the parent. Close the child sides of the pipes. */
591 if (s->is_subsystem) {
595 session_set_fds(s, pin[1], pout[0], perr[0], 0);
597 /* Enter the interactive session. */
598 server_loop(pid, pin[1], pout[0], perr[0]);
599 /* server_loop has closed pin[1], pout[0], and perr[0]. */
602 /* We are the parent. Close the child sides of the socket pairs. */
607 * Enter the interactive session. Note: server_loop must be able to
608 * handle the case that fdin and fdout are the same.
611 session_set_fds(s, inout[1], inout[1],
612 s->is_subsystem ? -1 : err[1], 0);
616 server_loop(pid, inout[1], inout[1], err[1]);
617 /* server_loop has closed inout[1] and err[1]. */
624 * This is called to fork and execute a command when we have a tty. This
625 * will call do_child from the child, and server_loop from the parent after
626 * setting up file descriptors, controlling tty, updating wtmp, utmp,
627 * lastlog, and other such operations.
630 do_exec_pty(Session *s, const char *command)
632 int fdout, ptyfd, ttyfd, ptymaster;
636 fatal("do_exec_pty: no session");
641 * Create another descriptor of the pty master side for use as the
642 * standard input. We could use the original descriptor, but this
643 * simplifies code in server_loop. The descriptor is bidirectional.
644 * Do this before forking (and cleanup in the child) so as to
645 * detect and gracefully fail out-of-fd conditions.
647 if ((fdout = dup(ptyfd)) < 0) {
648 error("%s: dup #1: %s", __func__, strerror(errno));
653 /* we keep a reference to the pty master */
654 if ((ptymaster = dup(ptyfd)) < 0) {
655 error("%s: dup #2: %s", __func__, strerror(errno));
662 /* Fork the child. */
663 switch ((pid = fork())) {
665 error("%s: fork: %.100s", __func__, strerror(errno));
677 /* Child. Reinitialize the log because the pid has changed. */
678 log_init(__progname, options.log_level,
679 options.log_facility, log_stderr);
680 /* Close the master side of the pseudo tty. */
683 /* Make the pseudo tty our controlling tty. */
684 pty_make_controlling_tty(&ttyfd, s->tty);
686 /* Redirect stdin/stdout/stderr from the pseudo tty. */
687 if (dup2(ttyfd, 0) < 0)
688 error("dup2 stdin: %s", strerror(errno));
689 if (dup2(ttyfd, 1) < 0)
690 error("dup2 stdout: %s", strerror(errno));
691 if (dup2(ttyfd, 2) < 0)
692 error("dup2 stderr: %s", strerror(errno));
694 /* Close the extra descriptor for the pseudo tty. */
697 /* record login, etc. similar to login(1) */
699 if (!(options.use_login && command == NULL)) {
701 cray_init_job(s->pw); /* set up cray jid and tmpdir */
703 do_login(s, command);
705 # ifdef LOGIN_NEEDS_UTMPX
711 * Do common processing for the child, such as execing
714 do_child(s, command);
721 signal(WJSIGNAL, cray_job_termination_handler);
725 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
730 /* Parent. Close the slave side of the pseudo tty. */
733 /* Enter interactive session. */
734 s->ptymaster = ptymaster;
735 packet_set_interactive(1);
737 session_set_fds(s, ptyfd, fdout, -1, 1);
739 server_loop(pid, ptyfd, fdout, -1);
740 /* server_loop _has_ closed ptyfd and fdout. */
745 #ifdef LOGIN_NEEDS_UTMPX
747 do_pre_login(Session *s)
750 struct sockaddr_storage from;
751 pid_t pid = getpid();
754 * Get IP address of client. If the connection is not a socket, let
755 * the address be 0.0.0.0.
757 memset(&from, 0, sizeof(from));
758 fromlen = sizeof(from);
759 if (packet_connection_is_on_socket()) {
760 if (getpeername(packet_get_connection_in(),
761 (struct sockaddr *)&from, &fromlen) < 0) {
762 debug("getpeername: %.100s", strerror(errno));
767 record_utmp_only(pid, s->tty, s->pw->pw_name,
768 get_remote_name_or_ip(utmp_len, options.use_dns),
769 (struct sockaddr *)&from, fromlen);
774 * This is called to fork and execute a command. If another command is
775 * to be forced, execute that instead.
778 do_exec(Session *s, const char *command)
782 if (options.adm_forced_command) {
783 original_command = command;
784 command = options.adm_forced_command;
785 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
786 s->is_subsystem = SUBSYSTEM_INT_SFTP;
787 else if (s->is_subsystem)
788 s->is_subsystem = SUBSYSTEM_EXT;
789 debug("Forced command (config) '%.900s'", command);
790 } else if (forced_command) {
791 original_command = command;
792 command = forced_command;
793 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
794 s->is_subsystem = SUBSYSTEM_INT_SFTP;
795 else if (s->is_subsystem)
796 s->is_subsystem = SUBSYSTEM_EXT;
797 debug("Forced command (key option) '%.900s'", command);
800 #ifdef SSH_AUDIT_EVENTS
802 PRIVSEP(audit_run_command(command));
803 else if (s->ttyfd == -1) {
804 char *shell = s->pw->pw_shell;
806 if (shell[0] == '\0') /* empty shell means /bin/sh */
808 PRIVSEP(audit_run_command(shell));
812 ret = do_exec_pty(s, command);
814 ret = do_exec_no_pty(s, command);
816 original_command = NULL;
819 * Clear loginmsg: it's the child's responsibility to display
820 * it to the user, otherwise multiple sessions may accumulate
821 * multiple copies of the login messages.
823 buffer_clear(&loginmsg);
828 /* administrative, login(1)-like work */
830 do_login(Session *s, const char *command)
833 struct sockaddr_storage from;
834 struct passwd * pw = s->pw;
835 pid_t pid = getpid();
838 * Get IP address of client. If the connection is not a socket, let
839 * the address be 0.0.0.0.
841 memset(&from, 0, sizeof(from));
842 fromlen = sizeof(from);
843 if (packet_connection_is_on_socket()) {
844 if (getpeername(packet_get_connection_in(),
845 (struct sockaddr *) & from, &fromlen) < 0) {
846 debug("getpeername: %.100s", strerror(errno));
851 /* Record that there was a login on that tty from the remote host. */
853 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
854 get_remote_name_or_ip(utmp_len,
856 (struct sockaddr *)&from, fromlen);
860 * If password change is needed, do it now.
861 * This needs to occur before the ~/.hushlogin check.
863 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
866 s->authctxt->force_pwchange = 0;
867 /* XXX - signal [net] parent to enable forwardings */
871 if (check_quietlogin(s, command))
880 * Display the message of the day.
887 #ifdef HAVE_LOGIN_CAP
891 #ifdef HAVE_LOGIN_CAP
892 fname = login_getcapstr(lc, "copyright", NULL, NULL);
893 if (fname != NULL && (f = fopen(fname, "r")) != NULL) {
894 while (fgets(buf, sizeof(buf), f) != NULL)
898 #endif /* HAVE_LOGIN_CAP */
899 (void)printf("%s\n\t%s %s\n",
900 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
901 "The Regents of the University of California. ",
902 "All rights reserved.");
906 if (options.print_motd) {
907 #ifdef HAVE_LOGIN_CAP
908 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
911 f = fopen("/etc/motd", "r");
914 while (fgets(buf, sizeof(buf), f))
923 * Check for quiet login, either .hushlogin or command given.
926 check_quietlogin(Session *s, const char *command)
929 struct passwd *pw = s->pw;
932 /* Return 1 if .hushlogin exists or a command given. */
935 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
936 #ifdef HAVE_LOGIN_CAP
937 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
940 if (stat(buf, &st) >= 0)
947 * Sets the value of the given variable in the environment. If the variable
948 * already exists, its value is overriden.
951 child_set_env(char ***envp, u_int *envsizep, const char *name,
959 * If we're passed an uninitialized list, allocate a single null
960 * entry before continuing.
962 if (*envp == NULL && *envsizep == 0) {
963 *envp = xmalloc(sizeof(char *));
969 * Find the slot where the value should be stored. If the variable
970 * already exists, we reuse the slot; otherwise we append a new slot
971 * at the end of the array, expanding if necessary.
974 namelen = strlen(name);
975 for (i = 0; env[i]; i++)
976 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
979 /* Reuse the slot. */
982 /* New variable. Expand if necessary. */
984 if (i >= envsize - 1) {
986 fatal("child_set_env: too many env vars");
988 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
991 /* Need to set the NULL pointer at end of array beyond the new slot. */
995 /* Allocate space and format the variable in the appropriate slot. */
996 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
997 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1001 * Reads environment variables from the given file and adds/overrides them
1002 * into the environment. If the file does not exist, this does nothing.
1003 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1004 * and assignments of the form name=value. No other forms are allowed.
1007 read_environment_file(char ***env, u_int *envsize,
1008 const char *filename)
1015 f = fopen(filename, "r");
1019 while (fgets(buf, sizeof(buf), f)) {
1020 if (++lineno > 1000)
1021 fatal("Too many lines in environment file %s", filename);
1022 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1024 if (!*cp || *cp == '#' || *cp == '\n')
1027 cp[strcspn(cp, "\n")] = '\0';
1029 value = strchr(cp, '=');
1030 if (value == NULL) {
1031 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1036 * Replace the equals sign by nul, and advance value to
1041 child_set_env(env, envsize, cp, value);
1046 #ifdef HAVE_ETC_DEFAULT_LOGIN
1048 * Return named variable from specified environment, or NULL if not present.
1051 child_get_env(char **env, const char *name)
1057 for (i=0; env[i] != NULL; i++)
1058 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1059 return(env[i] + len + 1);
1064 * Read /etc/default/login.
1065 * We pick up the PATH (or SUPATH for root) and UMASK.
1068 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1070 char **tmpenv = NULL, *var;
1071 u_int i, tmpenvsize = 0;
1075 * We don't want to copy the whole file to the child's environment,
1076 * so we use a temporary environment and copy the variables we're
1079 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1085 var = child_get_env(tmpenv, "SUPATH");
1087 var = child_get_env(tmpenv, "PATH");
1089 child_set_env(env, envsize, "PATH", var);
1091 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1092 if (sscanf(var, "%5lo", &mask) == 1)
1093 umask((mode_t)mask);
1095 for (i = 0; tmpenv[i] != NULL; i++)
1099 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1102 copy_environment(char **source, char ***env, u_int *envsize)
1104 char *var_name, *var_val;
1110 for(i = 0; source[i] != NULL; i++) {
1111 var_name = xstrdup(source[i]);
1112 if ((var_val = strstr(var_name, "=")) == NULL) {
1118 debug3("Copy environment: %s=%s", var_name, var_val);
1119 child_set_env(env, envsize, var_name, var_val);
1126 do_setup_env(Session *s, const char *shell)
1131 struct passwd *pw = s->pw;
1132 #ifndef HAVE_LOGIN_CAP
1135 extern char **environ;
1139 /* Initialize the environment. */
1141 env = xcalloc(envsize, sizeof(char *));
1146 * The Windows environment contains some setting which are
1147 * important for a running system. They must not be dropped.
1152 p = fetch_windows_environment();
1153 copy_environment(p, &env, &envsize);
1154 free_windows_environment(p);
1159 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1162 /* Allow any GSSAPI methods that we've used to alter
1163 * the childs environment as they see fit
1165 ssh_gssapi_do_child(&env, &envsize);
1168 if (!options.use_login) {
1169 /* Set basic environment. */
1170 for (i = 0; i < s->num_env; i++)
1171 child_set_env(&env, &envsize, s->env[i].name,
1174 child_set_env(&env, &envsize, "USER", pw->pw_name);
1175 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1177 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1179 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1180 snprintf(buf, sizeof buf, "%.200s/%.50s",
1181 _PATH_MAILDIR, pw->pw_name);
1182 child_set_env(&env, &envsize, "MAIL", buf);
1183 #ifdef HAVE_LOGIN_CAP
1184 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1185 child_set_env(&env, &envsize, "TERM", "su");
1187 environ = xmalloc(sizeof(char *));
1189 (void) setusercontext(lc, pw, pw->pw_uid,
1190 LOGIN_SETENV|LOGIN_SETPATH);
1191 copy_environment(environ, &env, &envsize);
1192 for (var = environ; *var != NULL; ++var)
1196 #else /* HAVE_LOGIN_CAP */
1197 # ifndef HAVE_CYGWIN
1199 * There's no standard path on Windows. The path contains
1200 * important components pointing to the system directories,
1201 * needed for loading shared libraries. So the path better
1202 * remains intact here.
1204 # ifdef HAVE_ETC_DEFAULT_LOGIN
1205 read_etc_default_login(&env, &envsize, pw->pw_uid);
1206 path = child_get_env(env, "PATH");
1207 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1208 if (path == NULL || *path == '\0') {
1209 child_set_env(&env, &envsize, "PATH",
1210 s->pw->pw_uid == 0 ?
1211 SUPERUSER_PATH : _PATH_STDPATH);
1213 # endif /* HAVE_CYGWIN */
1214 #endif /* HAVE_LOGIN_CAP */
1216 /* Normal systems set SHELL by default. */
1217 child_set_env(&env, &envsize, "SHELL", shell);
1220 /* Set custom environment options from RSA authentication. */
1221 if (!options.use_login) {
1222 while (custom_environment) {
1223 struct envstring *ce = custom_environment;
1226 for (i = 0; str[i] != '=' && str[i]; i++)
1228 if (str[i] == '=') {
1230 child_set_env(&env, &envsize, str, str + i + 1);
1232 custom_environment = ce->next;
1238 /* SSH_CLIENT deprecated */
1239 snprintf(buf, sizeof buf, "%.50s %d %d",
1240 get_remote_ipaddr(), get_remote_port(), get_local_port());
1241 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1243 laddr = get_local_ipaddr(packet_get_connection_in());
1244 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1245 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1247 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1250 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1252 child_set_env(&env, &envsize, "TERM", s->term);
1254 child_set_env(&env, &envsize, "DISPLAY", s->display);
1255 if (original_command)
1256 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1260 if (cray_tmpdir[0] != '\0')
1261 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1262 #endif /* _UNICOS */
1265 * Since we clear KRB5CCNAME at startup, if it's set now then it
1266 * must have been set by a native authentication method (eg AIX or
1267 * SIA), so copy it to the child.
1272 if ((cp = getenv("KRB5CCNAME")) != NULL)
1273 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1280 if ((cp = getenv("AUTHSTATE")) != NULL)
1281 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1282 read_environment_file(&env, &envsize, "/etc/environment");
1286 if (s->authctxt->krb5_ccname)
1287 child_set_env(&env, &envsize, "KRB5CCNAME",
1288 s->authctxt->krb5_ccname);
1292 * Pull in any environment variables that may have
1295 if (options.use_pam) {
1298 p = fetch_pam_child_environment();
1299 copy_environment(p, &env, &envsize);
1300 free_pam_environment(p);
1302 p = fetch_pam_environment();
1303 copy_environment(p, &env, &envsize);
1304 free_pam_environment(p);
1306 #endif /* USE_PAM */
1308 if (auth_sock_name != NULL)
1309 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1312 /* read $HOME/.ssh/environment. */
1313 if (options.permit_user_env && !options.use_login) {
1314 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1315 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1316 read_environment_file(&env, &envsize, buf);
1319 /* dump the environment */
1320 fprintf(stderr, "Environment:\n");
1321 for (i = 0; env[i]; i++)
1322 fprintf(stderr, " %.200s\n", env[i]);
1328 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1329 * first in this order).
1332 do_rc_files(Session *s, const char *shell)
1340 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1342 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1343 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1344 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1345 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1346 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1348 fprintf(stderr, "Running %s\n", cmd);
1349 f = popen(cmd, "w");
1352 fprintf(f, "%s %s\n", s->auth_proto,
1356 fprintf(stderr, "Could not run %s\n",
1358 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1360 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1361 _PATH_SSH_SYSTEM_RC);
1362 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1365 fprintf(f, "%s %s\n", s->auth_proto,
1369 fprintf(stderr, "Could not run %s\n",
1370 _PATH_SSH_SYSTEM_RC);
1371 } else if (do_xauth && options.xauth_location != NULL) {
1372 /* Add authority data to .Xauthority if appropriate. */
1375 "Running %.500s remove %.100s\n",
1376 options.xauth_location, s->auth_display);
1378 "%.500s add %.100s %.100s %.100s\n",
1379 options.xauth_location, s->auth_display,
1380 s->auth_proto, s->auth_data);
1382 snprintf(cmd, sizeof cmd, "%s -q -",
1383 options.xauth_location);
1384 f = popen(cmd, "w");
1386 fprintf(f, "remove %s\n",
1388 fprintf(f, "add %s %s %s\n",
1389 s->auth_display, s->auth_proto,
1393 fprintf(stderr, "Could not run %s\n",
1400 do_nologin(struct passwd *pw)
1405 #ifdef HAVE_LOGIN_CAP
1406 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1407 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1408 _PATH_NOLOGIN), "r");
1411 f = fopen(_PATH_NOLOGIN, "r");
1414 /* /etc/nologin exists. Print its contents and exit. */
1415 logit("User %.100s not allowed because %s exists",
1416 pw->pw_name, _PATH_NOLOGIN);
1417 while (fgets(buf, sizeof(buf), f))
1426 * Chroot into a directory after checking it for safety: all path components
1427 * must be root-owned directories with strict permissions.
1430 safely_chroot(const char *path, uid_t uid)
1433 char component[MAXPATHLEN];
1437 fatal("chroot path does not begin at root");
1438 if (strlen(path) >= sizeof(component))
1439 fatal("chroot path too long");
1442 * Descend the path, checking that each component is a
1443 * root-owned directory with strict permissions.
1445 for (cp = path; cp != NULL;) {
1446 if ((cp = strchr(cp, '/')) == NULL)
1447 strlcpy(component, path, sizeof(component));
1450 memcpy(component, path, cp - path);
1451 component[cp - path] = '\0';
1454 debug3("%s: checking '%s'", __func__, component);
1456 if (stat(component, &st) != 0)
1457 fatal("%s: stat(\"%s\"): %s", __func__,
1458 component, strerror(errno));
1459 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1460 fatal("bad ownership or modes for chroot "
1461 "directory %s\"%s\"",
1462 cp == NULL ? "" : "component ", component);
1463 if (!S_ISDIR(st.st_mode))
1464 fatal("chroot path %s\"%s\" is not a directory",
1465 cp == NULL ? "" : "component ", component);
1469 if (chdir(path) == -1)
1470 fatal("Unable to chdir to chroot path \"%s\": "
1471 "%s", path, strerror(errno));
1472 if (chroot(path) == -1)
1473 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1474 if (chdir("/") == -1)
1475 fatal("%s: chdir(/) after chroot: %s",
1476 __func__, strerror(errno));
1477 verbose("Changed root directory to \"%s\"", path);
1480 /* Set login name, uid, gid, and groups. */
1482 do_setusercontext(struct passwd *pw)
1484 char *chroot_path, *tmp;
1487 /* Cache selinux status for later use */
1488 (void)ssh_selinux_enabled();
1492 if (getuid() == 0 || geteuid() == 0)
1493 #endif /* HAVE_CYGWIN */
1496 #ifdef HAVE_SETPCRED
1497 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1498 fatal("Failed to set process credentials");
1499 #endif /* HAVE_SETPCRED */
1500 #ifdef HAVE_LOGIN_CAP
1505 if (options.use_pam) {
1506 do_pam_setcred(use_privsep);
1508 # endif /* USE_PAM */
1509 if (setusercontext(lc, pw, pw->pw_uid,
1510 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1511 perror("unable to set user context");
1515 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1516 /* Sets login uid for accounting */
1517 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1518 error("setluid: %s", strerror(errno));
1519 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1521 if (setlogin(pw->pw_name) < 0)
1522 error("setlogin failed: %s", strerror(errno));
1523 if (setgid(pw->pw_gid) < 0) {
1527 /* Initialize the group list. */
1528 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1529 perror("initgroups");
1535 * PAM credentials may take the form of supplementary groups.
1536 * These will have been wiped by the above initgroups() call.
1537 * Reestablish them here.
1539 if (options.use_pam) {
1540 do_pam_setcred(use_privsep);
1542 # endif /* USE_PAM */
1543 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1544 irix_setusercontext(pw);
1545 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1550 if (set_id(pw->pw_name) != 0) {
1553 # endif /* USE_LIBIAF */
1556 if (options.chroot_directory != NULL &&
1557 strcasecmp(options.chroot_directory, "none") != 0) {
1558 tmp = tilde_expand_filename(options.chroot_directory,
1560 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1561 "u", pw->pw_name, (char *)NULL);
1562 safely_chroot(chroot_path, pw->pw_uid);
1567 #ifdef HAVE_LOGIN_CAP
1568 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1569 perror("unable to set user context (setuser)");
1573 /* Permanently switch to the desired uid. */
1574 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);
1585 ssh_selinux_setup_exec_context(pw->pw_name);
1590 do_pwchange(Session *s)
1593 fprintf(stderr, "WARNING: Your password has expired.\n");
1594 if (s->ttyfd != -1) {
1596 "You must change your password now and login again!\n");
1597 #ifdef PASSWD_NEEDS_USERNAME
1598 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1601 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1606 "Password change required but no TTY available.\n");
1612 launch_login(struct passwd *pw, const char *hostname)
1614 /* Launch login(1). */
1616 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1617 #ifdef xxxLOGIN_NEEDS_TERM
1618 (s->term ? s->term : "unknown"),
1619 #endif /* LOGIN_NEEDS_TERM */
1620 #ifdef LOGIN_NO_ENDOPT
1621 "-p", "-f", pw->pw_name, (char *)NULL);
1623 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1626 /* Login couldn't be executed, die. */
1633 child_close_fds(void)
1637 if (packet_get_connection_in() == packet_get_connection_out())
1638 close(packet_get_connection_in());
1640 close(packet_get_connection_in());
1641 close(packet_get_connection_out());
1644 * Close all descriptors related to channels. They will still remain
1645 * open in the parent.
1647 /* XXX better use close-on-exec? -markus */
1648 channel_close_all();
1651 * Close any extra file descriptors. Note that there may still be
1652 * descriptors left by system functions. They will be closed later.
1657 * Close any extra open file descriptors so that we don't have them
1658 * hanging around in clients. Note that we want to do this after
1659 * initgroups, because at least on Solaris 2.3 it leaves file
1662 for (i = 3; i < 64; i++)
1667 * Performs common processing for the child, such as setting up the
1668 * environment, closing extra file descriptors, setting the user and group
1669 * ids, and executing the command or shell.
1673 do_child(Session *s, const char *command)
1675 extern char **environ;
1677 char *argv[ARGV_MAX];
1678 const char *shell, *shell0, *hostname = NULL;
1679 struct passwd *pw = s->pw;
1682 /* remove hostkey from the child's memory */
1683 destroy_sensitive_data();
1685 /* Force a password change */
1686 if (s->authctxt->force_pwchange) {
1687 do_setusercontext(pw);
1693 /* login(1) is only called if we execute the login shell */
1694 if (options.use_login && command != NULL)
1695 options.use_login = 0;
1698 cray_setup(pw->pw_uid, pw->pw_name, command);
1699 #endif /* _UNICOS */
1702 * Login(1) does this as well, and it needs uid 0 for the "-h"
1703 * switch, so we let login(1) to this for us.
1705 if (!options.use_login) {
1707 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1708 if (!check_quietlogin(s, command))
1710 #else /* HAVE_OSF_SIA */
1711 /* When PAM is enabled we rely on it to do the nologin check */
1712 if (!options.use_pam)
1714 do_setusercontext(pw);
1716 * PAM session modules in do_setusercontext may have
1717 * generated messages, so if this in an interactive
1718 * login then display them too.
1720 if (!check_quietlogin(s, command))
1722 #endif /* HAVE_OSF_SIA */
1726 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1727 debug3("PAM session not opened, exiting");
1734 * Get the shell from the password data. An empty shell field is
1735 * legal, and means /bin/sh.
1737 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1740 * Make sure $SHELL points to the shell from the password file,
1741 * even if shell is overridden from login.conf
1743 env = do_setup_env(s, shell);
1745 #ifdef HAVE_LOGIN_CAP
1746 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1749 /* we have to stash the hostname before we close our socket. */
1750 if (options.use_login)
1751 hostname = get_remote_name_or_ip(utmp_len,
1754 * Close the connection descriptors; note that this is the child, and
1755 * the server will still have the socket open, and it is important
1756 * that we do not shutdown it. Note that the descriptors cannot be
1757 * closed before building the environment, as we call
1758 * get_remote_ipaddr there.
1763 * Must take new environment into use so that .ssh/rc,
1764 * /etc/ssh/sshrc and xauth are run in the proper environment.
1768 #if defined(KRB5) && defined(USE_AFS)
1770 * At this point, we check to see if AFS is active and if we have
1771 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1772 * if we can (and need to) extend the ticket into an AFS token. If
1773 * we don't do this, we run into potential problems if the user's
1774 * home directory is in AFS and it's not world-readable.
1777 if (options.kerberos_get_afs_token && k_hasafs() &&
1778 (s->authctxt->krb5_ctx != NULL)) {
1781 debug("Getting AFS token");
1785 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1786 krb5_afslog(s->authctxt->krb5_ctx,
1787 s->authctxt->krb5_fwd_ccache, cell, NULL);
1789 krb5_afslog_home(s->authctxt->krb5_ctx,
1790 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1794 /* Change current directory to the user's home directory. */
1795 if (chdir(pw->pw_dir) < 0) {
1796 /* Suppress missing homedir warning for chroot case */
1797 #ifdef HAVE_LOGIN_CAP
1798 r = login_getcapbool(lc, "requirehome", 0);
1800 if (r || options.chroot_directory == NULL)
1801 fprintf(stderr, "Could not chdir to home "
1802 "directory %s: %s\n", pw->pw_dir,
1808 closefrom(STDERR_FILENO + 1);
1810 if (!options.use_login)
1811 do_rc_files(s, shell);
1813 /* restore SIGPIPE for child */
1814 signal(SIGPIPE, SIG_DFL);
1816 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1817 extern int optind, optreset;
1821 setproctitle("%s@internal-sftp-server", s->pw->pw_name);
1822 args = strdup(command ? command : "sftp-server");
1823 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1824 if (i < ARGV_MAX - 1)
1827 optind = optreset = 1;
1828 __progname = argv[0];
1829 exit(sftp_server_main(i, argv, s->pw));
1832 if (options.use_login) {
1833 launch_login(pw, hostname);
1837 /* Get the last component of the shell name. */
1838 if ((shell0 = strrchr(shell, '/')) != NULL)
1844 * If we have no command, execute the shell. In this case, the shell
1845 * name to be passed in argv[0] is preceded by '-' to indicate that
1846 * this is a login shell.
1851 /* Start the shell. Set initial character to '-'. */
1854 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1855 >= sizeof(argv0) - 1) {
1861 /* Execute the shell. */
1864 execve(shell, argv, env);
1866 /* Executing the shell failed. */
1871 * Execute the command using the user's shell. This uses the -c
1872 * option to execute the command.
1874 argv[0] = (char *) shell0;
1876 argv[2] = (char *) command;
1878 execve(shell, argv, env);
1884 session_unused(int id)
1886 debug3("%s: session id %d unused", __func__, id);
1887 if (id >= options.max_sessions ||
1888 id >= sessions_nalloc) {
1889 fatal("%s: insane session id %d (max %d nalloc %d)",
1890 __func__, id, options.max_sessions, sessions_nalloc);
1892 bzero(&sessions[id], sizeof(*sessions));
1893 sessions[id].self = id;
1894 sessions[id].used = 0;
1895 sessions[id].chanid = -1;
1896 sessions[id].ptyfd = -1;
1897 sessions[id].ttyfd = -1;
1898 sessions[id].ptymaster = -1;
1899 sessions[id].x11_chanids = NULL;
1900 sessions[id].next_unused = sessions_first_unused;
1901 sessions_first_unused = id;
1909 if (sessions_first_unused == -1) {
1910 if (sessions_nalloc >= options.max_sessions)
1912 debug2("%s: allocate (allocated %d max %d)",
1913 __func__, sessions_nalloc, options.max_sessions);
1914 tmp = xrealloc(sessions, sessions_nalloc + 1,
1917 error("%s: cannot allocate %d sessions",
1918 __func__, sessions_nalloc + 1);
1922 session_unused(sessions_nalloc++);
1925 if (sessions_first_unused >= sessions_nalloc ||
1926 sessions_first_unused < 0) {
1927 fatal("%s: insane first_unused %d max %d nalloc %d",
1928 __func__, sessions_first_unused, options.max_sessions,
1932 s = &sessions[sessions_first_unused];
1934 fatal("%s: session %d already used",
1935 __func__, sessions_first_unused);
1937 sessions_first_unused = s->next_unused;
1939 s->next_unused = -1;
1940 debug("session_new: session %d", s->self);
1949 for (i = 0; i < sessions_nalloc; i++) {
1950 Session *s = &sessions[i];
1952 debug("dump: used %d next_unused %d session %d %p "
1953 "channel %d pid %ld",
1964 session_open(Authctxt *authctxt, int chanid)
1966 Session *s = session_new();
1967 debug("session_open: channel %d", chanid);
1969 error("no more sessions");
1972 s->authctxt = authctxt;
1973 s->pw = authctxt->pw;
1974 if (s->pw == NULL || !authctxt->valid)
1975 fatal("no user for session %d", s->self);
1976 debug("session_open: session %d: link with channel %d", s->self, chanid);
1982 session_by_tty(char *tty)
1985 for (i = 0; i < sessions_nalloc; i++) {
1986 Session *s = &sessions[i];
1987 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1988 debug("session_by_tty: session %d tty %s", i, tty);
1992 debug("session_by_tty: unknown tty %.100s", tty);
1998 session_by_channel(int id)
2001 for (i = 0; i < sessions_nalloc; i++) {
2002 Session *s = &sessions[i];
2003 if (s->used && s->chanid == id) {
2004 debug("session_by_channel: session %d channel %d",
2009 debug("session_by_channel: unknown channel %d", id);
2015 session_by_x11_channel(int id)
2019 for (i = 0; i < sessions_nalloc; i++) {
2020 Session *s = &sessions[i];
2022 if (s->x11_chanids == NULL || !s->used)
2024 for (j = 0; s->x11_chanids[j] != -1; j++) {
2025 if (s->x11_chanids[j] == id) {
2026 debug("session_by_x11_channel: session %d "
2027 "channel %d", s->self, id);
2032 debug("session_by_x11_channel: unknown channel %d", id);
2038 session_by_pid(pid_t pid)
2041 debug("session_by_pid: pid %ld", (long)pid);
2042 for (i = 0; i < sessions_nalloc; i++) {
2043 Session *s = &sessions[i];
2044 if (s->used && s->pid == pid)
2047 error("session_by_pid: unknown pid %ld", (long)pid);
2053 session_window_change_req(Session *s)
2055 s->col = packet_get_int();
2056 s->row = packet_get_int();
2057 s->xpixel = packet_get_int();
2058 s->ypixel = packet_get_int();
2060 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2065 session_pty_req(Session *s)
2071 debug("Allocating a pty not permitted for this authentication.");
2074 if (s->ttyfd != -1) {
2075 packet_disconnect("Protocol error: you already have a pty.");
2079 s->term = packet_get_string(&len);
2082 s->col = packet_get_int();
2083 s->row = packet_get_int();
2085 s->row = packet_get_int();
2086 s->col = packet_get_int();
2088 s->xpixel = packet_get_int();
2089 s->ypixel = packet_get_int();
2091 if (strcmp(s->term, "") == 0) {
2096 /* Allocate a pty and open it. */
2097 debug("Allocating pty.");
2098 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2105 error("session_pty_req: session %d alloc failed", s->self);
2108 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2110 /* for SSH1 the tty modes length is not given */
2112 n_bytes = packet_remaining();
2113 tty_parse_modes(s->ttyfd, &n_bytes);
2116 pty_setowner(s->pw, s->tty);
2118 /* Set window size from the packet. */
2119 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2122 session_proctitle(s);
2127 session_subsystem_req(Session *s)
2132 char *prog, *cmd, *subsys = packet_get_string(&len);
2136 logit("subsystem request for %.100s", subsys);
2138 for (i = 0; i < options.num_subsystems; i++) {
2139 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2140 prog = options.subsystem_command[i];
2141 cmd = options.subsystem_args[i];
2142 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
2143 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2144 } else if (stat(prog, &st) < 0) {
2145 error("subsystem: cannot stat %s: %s", prog,
2149 s->is_subsystem = SUBSYSTEM_EXT;
2151 debug("subsystem: exec() %s", cmd);
2152 success = do_exec(s, cmd) == 0;
2158 logit("subsystem request for %.100s failed, subsystem not found",
2166 session_x11_req(Session *s)
2170 if (s->auth_proto != NULL || s->auth_data != NULL) {
2171 error("session_x11_req: session %d: "
2172 "x11 forwarding already active", s->self);
2175 s->single_connection = packet_get_char();
2176 s->auth_proto = packet_get_string(NULL);
2177 s->auth_data = packet_get_string(NULL);
2178 s->screen = packet_get_int();
2181 success = session_setup_x11fwd(s);
2183 xfree(s->auth_proto);
2184 xfree(s->auth_data);
2185 s->auth_proto = NULL;
2186 s->auth_data = NULL;
2192 session_shell_req(Session *s)
2195 return do_exec(s, NULL) == 0;
2199 session_exec_req(Session *s)
2203 char *command = packet_get_string(&len);
2205 success = do_exec(s, command) == 0;
2211 session_break_req(Session *s)
2214 packet_get_int(); /* ignored */
2217 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
2223 session_env_req(Session *s)
2226 u_int name_len, val_len, i;
2228 name = packet_get_string(&name_len);
2229 val = packet_get_string(&val_len);
2232 /* Don't set too many environment variables */
2233 if (s->num_env > 128) {
2234 debug2("Ignoring env request %s: too many env vars", name);
2238 for (i = 0; i < options.num_accept_env; i++) {
2239 if (match_pattern(name, options.accept_env[i])) {
2240 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2241 s->env = xrealloc(s->env, s->num_env + 1,
2243 s->env[s->num_env].name = name;
2244 s->env[s->num_env].val = val;
2249 debug2("Ignoring env request %s: disallowed name", name);
2258 session_auth_agent_req(Session *s)
2260 static int called = 0;
2262 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2263 debug("session_auth_agent_req: no_agent_forwarding_flag");
2270 return auth_input_request_forwarding(s->pw);
2275 session_input_channel_req(Channel *c, const char *rtype)
2280 if ((s = session_by_channel(c->self)) == NULL) {
2281 logit("session_input_channel_req: no session %d req %.100s",
2285 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2288 * a session is in LARVAL state until a shell, a command
2289 * or a subsystem is executed
2291 if (c->type == SSH_CHANNEL_LARVAL) {
2292 if (strcmp(rtype, "shell") == 0) {
2293 success = session_shell_req(s);
2294 } else if (strcmp(rtype, "exec") == 0) {
2295 success = session_exec_req(s);
2296 } else if (strcmp(rtype, "pty-req") == 0) {
2297 success = session_pty_req(s);
2298 } else if (strcmp(rtype, "x11-req") == 0) {
2299 success = session_x11_req(s);
2300 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2301 success = session_auth_agent_req(s);
2302 } else if (strcmp(rtype, "subsystem") == 0) {
2303 success = session_subsystem_req(s);
2304 } else if (strcmp(rtype, "env") == 0) {
2305 success = session_env_req(s);
2308 if (strcmp(rtype, "window-change") == 0) {
2309 success = session_window_change_req(s);
2310 } else if (strcmp(rtype, "break") == 0) {
2311 success = session_break_req(s);
2318 session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
2321 fatal("session_set_fds: called for proto != 2.0");
2323 * now that have a child and a pipe to the child,
2324 * we can activate our channel and register the fd's
2326 if (s->chanid == -1)
2327 fatal("no channel for session %d", s->self);
2328 channel_set_fds(s->chanid,
2330 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2331 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2335 * Function to perform pty cleanup. Also called if we get aborted abnormally
2336 * (e.g., due to a dropped connection).
2339 session_pty_cleanup2(Session *s)
2342 error("session_pty_cleanup: no session");
2348 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2350 /* Record that the user has logged out. */
2352 record_logout(s->pid, s->tty, s->pw->pw_name);
2354 /* Release the pseudo-tty. */
2356 pty_release(s->tty);
2359 * Close the server side of the socket pairs. We must do this after
2360 * the pty cleanup, so that another process doesn't get this pty
2361 * while we're still cleaning up.
2363 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2364 error("close(s->ptymaster/%d): %s",
2365 s->ptymaster, strerror(errno));
2367 /* unlink pty from session */
2372 session_pty_cleanup(Session *s)
2374 PRIVSEP(session_pty_cleanup2(s));
2380 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2395 return "SIG@openssh.com";
2399 session_close_x11(int id)
2403 if ((c = channel_by_id(id)) == NULL) {
2404 debug("session_close_x11: x11 channel %d missing", id);
2406 /* Detach X11 listener */
2407 debug("session_close_x11: detach x11 channel %d", id);
2408 channel_cancel_cleanup(id);
2409 if (c->ostate != CHAN_OUTPUT_CLOSED)
2415 session_close_single_x11(int id, void *arg)
2420 debug3("session_close_single_x11: channel %d", id);
2421 channel_cancel_cleanup(id);
2422 if ((s = session_by_x11_channel(id)) == NULL)
2423 fatal("session_close_single_x11: no x11 channel %d", id);
2424 for (i = 0; s->x11_chanids[i] != -1; i++) {
2425 debug("session_close_single_x11: session %d: "
2426 "closing channel %d", s->self, s->x11_chanids[i]);
2428 * The channel "id" is already closing, but make sure we
2429 * close all of its siblings.
2431 if (s->x11_chanids[i] != id)
2432 session_close_x11(s->x11_chanids[i]);
2434 xfree(s->x11_chanids);
2435 s->x11_chanids = NULL;
2440 if (s->auth_proto) {
2441 xfree(s->auth_proto);
2442 s->auth_proto = NULL;
2445 xfree(s->auth_data);
2446 s->auth_data = NULL;
2448 if (s->auth_display) {
2449 xfree(s->auth_display);
2450 s->auth_display = NULL;
2455 session_exit_message(Session *s, int status)
2459 if ((c = channel_lookup(s->chanid)) == NULL)
2460 fatal("session_exit_message: session %d: no channel %d",
2461 s->self, s->chanid);
2462 debug("session_exit_message: session %d channel %d pid %ld",
2463 s->self, s->chanid, (long)s->pid);
2465 if (WIFEXITED(status)) {
2466 channel_request_start(s->chanid, "exit-status", 0);
2467 packet_put_int(WEXITSTATUS(status));
2469 } else if (WIFSIGNALED(status)) {
2470 channel_request_start(s->chanid, "exit-signal", 0);
2471 packet_put_cstring(sig2name(WTERMSIG(status)));
2473 packet_put_char(WCOREDUMP(status)? 1 : 0);
2474 #else /* WCOREDUMP */
2476 #endif /* WCOREDUMP */
2477 packet_put_cstring("");
2478 packet_put_cstring("");
2481 /* Some weird exit cause. Just exit. */
2482 packet_disconnect("wait returned status %04x.", status);
2485 /* disconnect channel */
2486 debug("session_exit_message: release channel %d", s->chanid);
2489 * Adjust cleanup callback attachment to send close messages when
2490 * the channel gets EOF. The session will be then be closed
2491 * by session_close_by_channel when the childs close their fds.
2493 channel_register_cleanup(c->self, session_close_by_channel, 1);
2496 * emulate a write failure with 'chan_write_failed', nobody will be
2497 * interested in data we write.
2498 * Note that we must not call 'chan_read_failed', since there could
2499 * be some more data waiting in the pipe.
2501 if (c->ostate != CHAN_OUTPUT_CLOSED)
2502 chan_write_failed(c);
2506 session_close(Session *s)
2510 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2512 session_pty_cleanup(s);
2518 xfree(s->x11_chanids);
2519 if (s->auth_display)
2520 xfree(s->auth_display);
2522 xfree(s->auth_data);
2524 xfree(s->auth_proto);
2525 if (s->env != NULL) {
2526 for (i = 0; i < s->num_env; i++) {
2527 xfree(s->env[i].name);
2528 xfree(s->env[i].val);
2532 session_proctitle(s);
2533 session_unused(s->self);
2537 session_close_by_pid(pid_t pid, int status)
2539 Session *s = session_by_pid(pid);
2541 debug("session_close_by_pid: no session for pid %ld",
2545 if (s->chanid != -1)
2546 session_exit_message(s, status);
2548 session_pty_cleanup(s);
2553 * this is called when a channel dies before
2554 * the session 'child' itself dies
2557 session_close_by_channel(int id, void *arg)
2559 Session *s = session_by_channel(id);
2563 debug("session_close_by_channel: no session for id %d", id);
2566 debug("session_close_by_channel: channel %d child %ld",
2569 debug("session_close_by_channel: channel %d: has child", id);
2571 * delay detach of session, but release pty, since
2572 * the fd's to the child are already closed
2575 session_pty_cleanup(s);
2578 /* detach by removing callback */
2579 channel_cancel_cleanup(s->chanid);
2581 /* Close any X11 listeners associated with this session */
2582 if (s->x11_chanids != NULL) {
2583 for (i = 0; s->x11_chanids[i] != -1; i++) {
2584 session_close_x11(s->x11_chanids[i]);
2585 s->x11_chanids[i] = -1;
2594 session_destroy_all(void (*closefunc)(Session *))
2597 for (i = 0; i < sessions_nalloc; i++) {
2598 Session *s = &sessions[i];
2600 if (closefunc != NULL)
2609 session_tty_list(void)
2611 static char buf[1024];
2616 for (i = 0; i < sessions_nalloc; i++) {
2617 Session *s = &sessions[i];
2618 if (s->used && s->ttyfd != -1) {
2620 if (strncmp(s->tty, "/dev/", 5) != 0) {
2621 cp = strrchr(s->tty, '/');
2622 cp = (cp == NULL) ? s->tty : cp + 1;
2627 strlcat(buf, ",", sizeof buf);
2628 strlcat(buf, cp, sizeof buf);
2632 strlcpy(buf, "notty", sizeof buf);
2637 session_proctitle(Session *s)
2640 error("no user for session %d", s->self);
2642 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2646 session_setup_x11fwd(Session *s)
2649 char display[512], auth_display[512];
2650 char hostname[MAXHOSTNAMELEN];
2653 if (no_x11_forwarding_flag) {
2654 packet_send_debug("X11 forwarding disabled in user configuration file.");
2657 if (!options.x11_forwarding) {
2658 debug("X11 forwarding disabled in server configuration file.");
2661 if (!options.xauth_location ||
2662 (stat(options.xauth_location, &st) == -1)) {
2663 packet_send_debug("No xauth program; cannot forward with spoofing.");
2666 if (options.use_login) {
2667 packet_send_debug("X11 forwarding disabled; "
2668 "not compatible with UseLogin=yes.");
2671 if (s->display != NULL) {
2672 debug("X11 display already set.");
2675 if (x11_create_display_inet(options.x11_display_offset,
2676 options.x11_use_localhost, s->single_connection,
2677 &s->display_number, &s->x11_chanids) == -1) {
2678 debug("x11_create_display_inet failed.");
2681 for (i = 0; s->x11_chanids[i] != -1; i++) {
2682 channel_register_cleanup(s->x11_chanids[i],
2683 session_close_single_x11, 0);
2686 /* Set up a suitable value for the DISPLAY variable. */
2687 if (gethostname(hostname, sizeof(hostname)) < 0)
2688 fatal("gethostname: %.100s", strerror(errno));
2690 * auth_display must be used as the displayname when the
2691 * authorization entry is added with xauth(1). This will be
2692 * different than the DISPLAY string for localhost displays.
2694 if (options.x11_use_localhost) {
2695 snprintf(display, sizeof display, "localhost:%u.%u",
2696 s->display_number, s->screen);
2697 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2698 s->display_number, s->screen);
2699 s->display = xstrdup(display);
2700 s->auth_display = xstrdup(auth_display);
2702 #ifdef IPADDR_IN_DISPLAY
2704 struct in_addr my_addr;
2706 he = gethostbyname(hostname);
2708 error("Can't get IP address for X11 DISPLAY.");
2709 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2712 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2713 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2714 s->display_number, s->screen);
2716 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2717 s->display_number, s->screen);
2719 s->display = xstrdup(display);
2720 s->auth_display = xstrdup(display);
2727 do_authenticated2(Authctxt *authctxt)
2729 server_loop2(authctxt);
2733 do_cleanup(Authctxt *authctxt)
2735 static int called = 0;
2737 debug("do_cleanup");
2739 /* no cleanup if we're in the child for login shell */
2743 /* avoid double cleanup */
2748 if (authctxt == NULL)
2752 if (options.use_pam) {
2754 sshpam_thread_cleanup();
2758 if (!authctxt->authenticated)
2762 if (options.kerberos_ticket_cleanup &&
2764 krb5_cleanup_proc(authctxt);
2768 if (compat20 && options.gss_cleanup_creds)
2769 ssh_gssapi_cleanup_creds();
2772 /* remove agent socket */
2773 auth_sock_cleanup_proc(authctxt->pw);
2776 * Cleanup ptys/utmp only if privsep is disabled,
2777 * or if running in monitor.
2779 if (!use_privsep || mm_is_monitor())
2780 session_destroy_all(session_pty_cleanup2);