1 /* $OpenBSD: session.c,v 1.270 2014/01/31 16:39:19 tedu Exp $ */
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 #include <sys/types.h>
39 #include <sys/param.h>
40 #ifdef HAVE_SYS_STAT_H
41 # include <sys/stat.h>
43 #include <sys/socket.h>
47 #include <arpa/inet.h>
63 #include "openbsd-compat/sys-queue.h"
82 #include "auth-options.h"
84 #include "pathnames.h"
88 #include "serverloop.h"
93 #include "monitor_wrap.h"
96 #if defined(KRB5) && defined(USE_AFS)
101 #include <selinux/selinux.h>
104 #define IS_INTERNAL_SFTP(c) \
105 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
106 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
107 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
108 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
112 Session *session_new(void);
113 void session_set_fds(Session *, int, int, int, int, int);
114 void session_pty_cleanup(Session *);
115 void session_proctitle(Session *);
116 int session_setup_x11fwd(Session *);
117 int do_exec_pty(Session *, const char *);
118 int do_exec_no_pty(Session *, const char *);
119 int do_exec(Session *, const char *);
120 void do_login(Session *, const char *);
121 #ifdef LOGIN_NEEDS_UTMPX
122 static void do_pre_login(Session *s);
124 void do_child(Session *, const char *);
126 int check_quietlogin(Session *, const char *);
128 static void do_authenticated1(Authctxt *);
129 static void do_authenticated2(Authctxt *);
131 static int session_pty_req(Session *);
134 extern ServerOptions options;
135 extern char *__progname;
136 extern int log_stderr;
137 extern int debug_flag;
138 extern u_int utmp_len;
139 extern int startup_pipe;
140 extern void destroy_sensitive_data(void);
141 extern Buffer loginmsg;
143 /* original command from peer. */
144 const char *original_command = NULL;
147 static int sessions_first_unused = -1;
148 static int sessions_nalloc = 0;
149 static Session *sessions = NULL;
151 #define SUBSYSTEM_NONE 0
152 #define SUBSYSTEM_EXT 1
153 #define SUBSYSTEM_INT_SFTP 2
154 #define SUBSYSTEM_INT_SFTP_ERROR 3
156 #ifdef HAVE_LOGIN_CAP
160 static int is_child = 0;
162 /* Name and directory of socket for authentication agent forwarding. */
163 static char *auth_sock_name = NULL;
164 static char *auth_sock_dir = NULL;
166 /* removes the agent forwarding socket */
169 auth_sock_cleanup_proc(struct passwd *pw)
171 if (auth_sock_name != NULL) {
172 temporarily_use_uid(pw);
173 unlink(auth_sock_name);
174 rmdir(auth_sock_dir);
175 auth_sock_name = NULL;
181 auth_input_request_forwarding(struct passwd * pw)
185 struct sockaddr_un sunaddr;
187 if (auth_sock_name != NULL) {
188 error("authentication forwarding requested twice.");
192 /* Temporarily drop privileged uid for mkdir/bind. */
193 temporarily_use_uid(pw);
195 /* Allocate a buffer for the socket name, and format the name. */
196 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
198 /* Create private directory for socket */
199 if (mkdtemp(auth_sock_dir) == NULL) {
200 packet_send_debug("Agent forwarding disabled: "
201 "mkdtemp() failed: %.100s", strerror(errno));
204 auth_sock_dir = NULL;
208 xasprintf(&auth_sock_name, "%s/agent.%ld",
209 auth_sock_dir, (long) getpid());
211 /* Create the socket. */
212 sock = socket(AF_UNIX, SOCK_STREAM, 0);
214 error("socket: %.100s", strerror(errno));
219 /* Bind it to the name. */
220 memset(&sunaddr, 0, sizeof(sunaddr));
221 sunaddr.sun_family = AF_UNIX;
222 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
224 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
225 error("bind: %.100s", strerror(errno));
230 /* Restore the privileged uid. */
233 /* Start listening on the socket. */
234 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
235 error("listen: %.100s", strerror(errno));
239 /* Allocate a channel for the authentication agent socket. */
240 nc = channel_new("auth socket",
241 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
242 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
243 0, "auth socket", 1);
244 nc->path = xstrdup(auth_sock_name);
248 free(auth_sock_name);
249 if (auth_sock_dir != NULL) {
250 rmdir(auth_sock_dir);
255 auth_sock_name = NULL;
256 auth_sock_dir = NULL;
261 display_loginmsg(void)
263 if (buffer_len(&loginmsg) > 0) {
264 buffer_append(&loginmsg, "\0", 1);
265 printf("%s", (char *)buffer_ptr(&loginmsg));
266 buffer_clear(&loginmsg);
271 do_authenticated(Authctxt *authctxt)
273 setproctitle("%s", authctxt->pw->pw_name);
275 /* setup the channel layer */
276 if (no_port_forwarding_flag ||
277 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
278 channel_disable_adm_local_opens();
280 channel_permit_all_opens();
285 do_authenticated2(authctxt);
287 do_authenticated1(authctxt);
289 do_cleanup(authctxt);
293 * Prepares for an interactive session. This is called after the user has
294 * been successfully authenticated. During this message exchange, pseudo
295 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
296 * are requested, etc.
299 do_authenticated1(Authctxt *authctxt)
303 int success, type, screen_flag;
304 int enable_compression_after_reply = 0;
305 u_int proto_len, data_len, dlen, compression_level = 0;
309 error("no more sessions");
312 s->authctxt = authctxt;
313 s->pw = authctxt->pw;
316 * We stay in this loop until the client requests to execute a shell
322 /* Get a packet from the client. */
323 type = packet_read();
325 /* Process the packet. */
327 case SSH_CMSG_REQUEST_COMPRESSION:
328 compression_level = packet_get_int();
330 if (compression_level < 1 || compression_level > 9) {
331 packet_send_debug("Received invalid compression level %d.",
335 if (options.compression == COMP_NONE) {
336 debug2("compression disabled");
339 /* Enable compression after we have responded with SUCCESS. */
340 enable_compression_after_reply = 1;
344 case SSH_CMSG_REQUEST_PTY:
345 success = session_pty_req(s);
348 case SSH_CMSG_X11_REQUEST_FORWARDING:
349 s->auth_proto = packet_get_string(&proto_len);
350 s->auth_data = packet_get_string(&data_len);
352 screen_flag = packet_get_protocol_flags() &
353 SSH_PROTOFLAG_SCREEN_NUMBER;
354 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
356 if (packet_remaining() == 4) {
358 debug2("Buggy client: "
359 "X11 screen flag missing");
360 s->screen = packet_get_int();
365 success = session_setup_x11fwd(s);
369 s->auth_proto = NULL;
374 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
375 if (!options.allow_agent_forwarding ||
376 no_agent_forwarding_flag || compat13) {
377 debug("Authentication agent forwarding not permitted for this authentication.");
380 debug("Received authentication agent forwarding request.");
381 success = auth_input_request_forwarding(s->pw);
384 case SSH_CMSG_PORT_FORWARD_REQUEST:
385 if (no_port_forwarding_flag) {
386 debug("Port forwarding not permitted for this authentication.");
389 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
390 debug("Port forwarding not permitted.");
393 debug("Received TCP/IP port forwarding request.");
394 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
395 options.gateway_ports) < 0) {
396 debug("Port forwarding failed.");
402 case SSH_CMSG_MAX_PACKET_SIZE:
403 if (packet_set_maxsize(packet_get_int()) > 0)
407 case SSH_CMSG_EXEC_SHELL:
408 case SSH_CMSG_EXEC_CMD:
409 if (type == SSH_CMSG_EXEC_CMD) {
410 command = packet_get_string(&dlen);
411 debug("Exec command '%.500s'", command);
412 if (do_exec(s, command) != 0)
414 "command execution failed");
417 if (do_exec(s, NULL) != 0)
419 "shell execution failed");
427 * Any unknown messages in this phase are ignored,
428 * and a failure message is returned.
430 logit("Unknown packet type received after authentication: %d", type);
432 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
436 /* Enable compression now that we have replied if appropriate. */
437 if (enable_compression_after_reply) {
438 enable_compression_after_reply = 0;
439 packet_start_compression(compression_level);
446 * This is called to fork and execute a command when we have no tty. This
447 * will call do_child from the child, and server_loop from the parent after
448 * setting up file descriptors and such.
451 do_exec_no_pty(Session *s, const char *command)
456 int pin[2], pout[2], perr[2];
459 fatal("do_exec_no_pty: no session");
461 /* Allocate pipes for communicating with the program. */
463 error("%s: pipe in: %.100s", __func__, strerror(errno));
466 if (pipe(pout) < 0) {
467 error("%s: pipe out: %.100s", __func__, strerror(errno));
472 if (pipe(perr) < 0) {
473 error("%s: pipe err: %.100s", __func__,
482 int inout[2], err[2];
485 fatal("do_exec_no_pty: no session");
487 /* Uses socket pairs to communicate with the program. */
488 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
489 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
492 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
493 error("%s: socketpair #2: %.100s", __func__,
501 session_proctitle(s);
503 /* Fork the child. */
504 switch ((pid = fork())) {
506 error("%s: fork: %.100s", __func__, strerror(errno));
524 /* Child. Reinitialize the log since the pid has changed. */
525 log_init(__progname, options.log_level,
526 options.log_facility, log_stderr);
529 * Create a new session and process group since the 4.4BSD
530 * setlogin() affects the entire process group.
533 error("setsid failed: %.100s", strerror(errno));
537 * Redirect stdin. We close the parent side of the socket
538 * pair, and make the child side the standard input.
541 if (dup2(pin[0], 0) < 0)
542 perror("dup2 stdin");
545 /* Redirect stdout. */
547 if (dup2(pout[1], 1) < 0)
548 perror("dup2 stdout");
551 /* Redirect stderr. */
553 if (dup2(perr[1], 2) < 0)
554 perror("dup2 stderr");
558 * Redirect stdin, stdout, and stderr. Stdin and stdout will
559 * use the same socket, as some programs (particularly rdist)
560 * seem to depend on it.
564 if (dup2(inout[0], 0) < 0) /* stdin */
565 perror("dup2 stdin");
566 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
567 perror("dup2 stdout");
569 if (dup2(err[0], 2) < 0) /* stderr */
570 perror("dup2 stderr");
576 cray_init_job(s->pw); /* set up cray jid and tmpdir */
579 /* Do processing for the child (exec command etc). */
580 do_child(s, command);
587 signal(WJSIGNAL, cray_job_termination_handler);
590 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
594 /* Set interactive/non-interactive mode. */
595 packet_set_interactive(s->display != NULL,
596 options.ip_qos_interactive, options.ip_qos_bulk);
599 * Clear loginmsg, since it's the child's responsibility to display
600 * it to the user, otherwise multiple sessions may accumulate
601 * multiple copies of the login messages.
603 buffer_clear(&loginmsg);
606 /* We are the parent. Close the child sides of the pipes. */
612 session_set_fds(s, pin[1], pout[0], perr[0],
615 /* Enter the interactive session. */
616 server_loop(pid, pin[1], pout[0], perr[0]);
617 /* server_loop has closed pin[1], pout[0], and perr[0]. */
620 /* We are the parent. Close the child sides of the socket pairs. */
625 * Enter the interactive session. Note: server_loop must be able to
626 * handle the case that fdin and fdout are the same.
629 session_set_fds(s, inout[1], inout[1], err[1],
632 server_loop(pid, inout[1], inout[1], err[1]);
633 /* server_loop has closed inout[1] and err[1]. */
640 * This is called to fork and execute a command when we have a tty. This
641 * will call do_child from the child, and server_loop from the parent after
642 * setting up file descriptors, controlling tty, updating wtmp, utmp,
643 * lastlog, and other such operations.
646 do_exec_pty(Session *s, const char *command)
648 int fdout, ptyfd, ttyfd, ptymaster;
652 fatal("do_exec_pty: no session");
657 * Create another descriptor of the pty master side for use as the
658 * standard input. We could use the original descriptor, but this
659 * simplifies code in server_loop. The descriptor is bidirectional.
660 * Do this before forking (and cleanup in the child) so as to
661 * detect and gracefully fail out-of-fd conditions.
663 if ((fdout = dup(ptyfd)) < 0) {
664 error("%s: dup #1: %s", __func__, strerror(errno));
669 /* we keep a reference to the pty master */
670 if ((ptymaster = dup(ptyfd)) < 0) {
671 error("%s: dup #2: %s", __func__, strerror(errno));
678 /* Fork the child. */
679 switch ((pid = fork())) {
681 error("%s: fork: %.100s", __func__, strerror(errno));
693 /* Child. Reinitialize the log because the pid has changed. */
694 log_init(__progname, options.log_level,
695 options.log_facility, log_stderr);
696 /* Close the master side of the pseudo tty. */
699 /* Make the pseudo tty our controlling tty. */
700 pty_make_controlling_tty(&ttyfd, s->tty);
702 /* Redirect stdin/stdout/stderr from the pseudo tty. */
703 if (dup2(ttyfd, 0) < 0)
704 error("dup2 stdin: %s", strerror(errno));
705 if (dup2(ttyfd, 1) < 0)
706 error("dup2 stdout: %s", strerror(errno));
707 if (dup2(ttyfd, 2) < 0)
708 error("dup2 stderr: %s", strerror(errno));
710 /* Close the extra descriptor for the pseudo tty. */
713 /* record login, etc. similar to login(1) */
715 if (!(options.use_login && command == NULL)) {
717 cray_init_job(s->pw); /* set up cray jid and tmpdir */
719 do_login(s, command);
721 # ifdef LOGIN_NEEDS_UTMPX
727 * Do common processing for the child, such as execing
730 do_child(s, command);
737 signal(WJSIGNAL, cray_job_termination_handler);
740 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
745 /* Parent. Close the slave side of the pseudo tty. */
748 /* Enter interactive session. */
749 s->ptymaster = ptymaster;
750 packet_set_interactive(1,
751 options.ip_qos_interactive, options.ip_qos_bulk);
753 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
755 server_loop(pid, ptyfd, fdout, -1);
756 /* server_loop _has_ closed ptyfd and fdout. */
761 #ifdef LOGIN_NEEDS_UTMPX
763 do_pre_login(Session *s)
766 struct sockaddr_storage from;
767 pid_t pid = getpid();
770 * Get IP address of client. If the connection is not a socket, let
771 * the address be 0.0.0.0.
773 memset(&from, 0, sizeof(from));
774 fromlen = sizeof(from);
775 if (packet_connection_is_on_socket()) {
776 if (getpeername(packet_get_connection_in(),
777 (struct sockaddr *)&from, &fromlen) < 0) {
778 debug("getpeername: %.100s", strerror(errno));
783 record_utmp_only(pid, s->tty, s->pw->pw_name,
784 get_remote_name_or_ip(utmp_len, options.use_dns),
785 (struct sockaddr *)&from, fromlen);
790 * This is called to fork and execute a command. If another command is
791 * to be forced, execute that instead.
794 do_exec(Session *s, const char *command)
797 const char *forced = NULL;
798 char session_type[1024], *tty = NULL;
800 if (options.adm_forced_command) {
801 original_command = command;
802 command = options.adm_forced_command;
804 } else if (forced_command) {
805 original_command = command;
806 command = forced_command;
807 forced = "(key-option)";
809 if (forced != NULL) {
810 if (IS_INTERNAL_SFTP(command)) {
811 s->is_subsystem = s->is_subsystem ?
812 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
813 } else if (s->is_subsystem)
814 s->is_subsystem = SUBSYSTEM_EXT;
815 snprintf(session_type, sizeof(session_type),
816 "forced-command %s '%.900s'", forced, command);
817 } else if (s->is_subsystem) {
818 snprintf(session_type, sizeof(session_type),
819 "subsystem '%.900s'", s->subsys);
820 } else if (command == NULL) {
821 snprintf(session_type, sizeof(session_type), "shell");
823 /* NB. we don't log unforced commands to preserve privacy */
824 snprintf(session_type, sizeof(session_type), "command");
827 if (s->ttyfd != -1) {
829 if (strncmp(tty, "/dev/", 5) == 0)
833 verbose("Starting session: %s%s%s for %s from %.200s port %d",
835 tty == NULL ? "" : " on ",
836 tty == NULL ? "" : tty,
841 #ifdef SSH_AUDIT_EVENTS
843 PRIVSEP(audit_run_command(command));
844 else if (s->ttyfd == -1) {
845 char *shell = s->pw->pw_shell;
847 if (shell[0] == '\0') /* empty shell means /bin/sh */
849 PRIVSEP(audit_run_command(shell));
853 ret = do_exec_pty(s, command);
855 ret = do_exec_no_pty(s, command);
857 original_command = NULL;
860 * Clear loginmsg: it's the child's responsibility to display
861 * it to the user, otherwise multiple sessions may accumulate
862 * multiple copies of the login messages.
864 buffer_clear(&loginmsg);
869 /* administrative, login(1)-like work */
871 do_login(Session *s, const char *command)
874 struct sockaddr_storage from;
875 struct passwd * pw = s->pw;
876 pid_t pid = getpid();
879 * Get IP address of client. If the connection is not a socket, let
880 * the address be 0.0.0.0.
882 memset(&from, 0, sizeof(from));
883 fromlen = sizeof(from);
884 if (packet_connection_is_on_socket()) {
885 if (getpeername(packet_get_connection_in(),
886 (struct sockaddr *)&from, &fromlen) < 0) {
887 debug("getpeername: %.100s", strerror(errno));
892 /* Record that there was a login on that tty from the remote host. */
894 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
895 get_remote_name_or_ip(utmp_len,
897 (struct sockaddr *)&from, fromlen);
901 * If password change is needed, do it now.
902 * This needs to occur before the ~/.hushlogin check.
904 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
907 s->authctxt->force_pwchange = 0;
908 /* XXX - signal [net] parent to enable forwardings */
912 if (check_quietlogin(s, command))
921 * Display the message of the day.
929 if (options.print_motd) {
930 #ifdef HAVE_LOGIN_CAP
931 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
934 f = fopen("/etc/motd", "r");
937 while (fgets(buf, sizeof(buf), f))
946 * Check for quiet login, either .hushlogin or command given.
949 check_quietlogin(Session *s, const char *command)
952 struct passwd *pw = s->pw;
955 /* Return 1 if .hushlogin exists or a command given. */
958 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
959 #ifdef HAVE_LOGIN_CAP
960 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
963 if (stat(buf, &st) >= 0)
970 * Sets the value of the given variable in the environment. If the variable
971 * already exists, its value is overridden.
974 child_set_env(char ***envp, u_int *envsizep, const char *name,
981 if (strchr(name, '=') != NULL) {
982 error("Invalid environment variable \"%.100s\"", name);
987 * If we're passed an uninitialized list, allocate a single null
988 * entry before continuing.
990 if (*envp == NULL && *envsizep == 0) {
991 *envp = xmalloc(sizeof(char *));
997 * Find the slot where the value should be stored. If the variable
998 * already exists, we reuse the slot; otherwise we append a new slot
999 * at the end of the array, expanding if necessary.
1002 namelen = strlen(name);
1003 for (i = 0; env[i]; i++)
1004 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1007 /* Reuse the slot. */
1010 /* New variable. Expand if necessary. */
1011 envsize = *envsizep;
1012 if (i >= envsize - 1) {
1013 if (envsize >= 1000)
1014 fatal("child_set_env: too many env vars");
1016 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1017 *envsizep = envsize;
1019 /* Need to set the NULL pointer at end of array beyond the new slot. */
1023 /* Allocate space and format the variable in the appropriate slot. */
1024 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1025 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1029 * Reads environment variables from the given file and adds/overrides them
1030 * into the environment. If the file does not exist, this does nothing.
1031 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1032 * and assignments of the form name=value. No other forms are allowed.
1035 read_environment_file(char ***env, u_int *envsize,
1036 const char *filename)
1043 f = fopen(filename, "r");
1047 while (fgets(buf, sizeof(buf), f)) {
1048 if (++lineno > 1000)
1049 fatal("Too many lines in environment file %s", filename);
1050 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1052 if (!*cp || *cp == '#' || *cp == '\n')
1055 cp[strcspn(cp, "\n")] = '\0';
1057 value = strchr(cp, '=');
1058 if (value == NULL) {
1059 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1064 * Replace the equals sign by nul, and advance value to
1069 child_set_env(env, envsize, cp, value);
1074 #ifdef HAVE_ETC_DEFAULT_LOGIN
1076 * Return named variable from specified environment, or NULL if not present.
1079 child_get_env(char **env, const char *name)
1085 for (i=0; env[i] != NULL; i++)
1086 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1087 return(env[i] + len + 1);
1092 * Read /etc/default/login.
1093 * We pick up the PATH (or SUPATH for root) and UMASK.
1096 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1098 char **tmpenv = NULL, *var;
1099 u_int i, tmpenvsize = 0;
1103 * We don't want to copy the whole file to the child's environment,
1104 * so we use a temporary environment and copy the variables we're
1107 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1113 var = child_get_env(tmpenv, "SUPATH");
1115 var = child_get_env(tmpenv, "PATH");
1117 child_set_env(env, envsize, "PATH", var);
1119 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1120 if (sscanf(var, "%5lo", &mask) == 1)
1121 umask((mode_t)mask);
1123 for (i = 0; tmpenv[i] != NULL; i++)
1127 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1130 copy_environment(char **source, char ***env, u_int *envsize)
1132 char *var_name, *var_val;
1138 for(i = 0; source[i] != NULL; i++) {
1139 var_name = xstrdup(source[i]);
1140 if ((var_val = strstr(var_name, "=")) == NULL) {
1146 debug3("Copy environment: %s=%s", var_name, var_val);
1147 child_set_env(env, envsize, var_name, var_val);
1154 do_setup_env(Session *s, const char *shell, int *env_size)
1159 struct passwd *pw = s->pw;
1160 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1164 /* Initialize the environment. */
1166 env = xcalloc(envsize, sizeof(char *));
1171 * The Windows environment contains some setting which are
1172 * important for a running system. They must not be dropped.
1177 p = fetch_windows_environment();
1178 copy_environment(p, &env, &envsize);
1179 free_windows_environment(p);
1184 /* Allow any GSSAPI methods that we've used to alter
1185 * the childs environment as they see fit
1187 ssh_gssapi_do_child(&env, &envsize);
1190 if (!options.use_login) {
1191 /* Set basic environment. */
1192 for (i = 0; i < s->num_env; i++)
1193 child_set_env(&env, &envsize, s->env[i].name,
1196 child_set_env(&env, &envsize, "USER", pw->pw_name);
1197 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1199 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1201 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1202 #ifdef HAVE_LOGIN_CAP
1203 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1204 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1206 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1207 #else /* HAVE_LOGIN_CAP */
1208 # ifndef HAVE_CYGWIN
1210 * There's no standard path on Windows. The path contains
1211 * important components pointing to the system directories,
1212 * needed for loading shared libraries. So the path better
1213 * remains intact here.
1215 # ifdef HAVE_ETC_DEFAULT_LOGIN
1216 read_etc_default_login(&env, &envsize, pw->pw_uid);
1217 path = child_get_env(env, "PATH");
1218 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1219 if (path == NULL || *path == '\0') {
1220 child_set_env(&env, &envsize, "PATH",
1221 s->pw->pw_uid == 0 ?
1222 SUPERUSER_PATH : _PATH_STDPATH);
1224 # endif /* HAVE_CYGWIN */
1225 #endif /* HAVE_LOGIN_CAP */
1227 snprintf(buf, sizeof buf, "%.200s/%.50s",
1228 _PATH_MAILDIR, pw->pw_name);
1229 child_set_env(&env, &envsize, "MAIL", buf);
1231 /* Normal systems set SHELL by default. */
1232 child_set_env(&env, &envsize, "SHELL", shell);
1235 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1237 /* Set custom environment options from RSA authentication. */
1238 if (!options.use_login) {
1239 while (custom_environment) {
1240 struct envstring *ce = custom_environment;
1243 for (i = 0; str[i] != '=' && str[i]; i++)
1245 if (str[i] == '=') {
1247 child_set_env(&env, &envsize, str, str + i + 1);
1249 custom_environment = ce->next;
1255 /* SSH_CLIENT deprecated */
1256 snprintf(buf, sizeof buf, "%.50s %d %d",
1257 get_remote_ipaddr(), get_remote_port(), get_local_port());
1258 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1260 laddr = get_local_ipaddr(packet_get_connection_in());
1261 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1262 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1264 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1267 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1269 child_set_env(&env, &envsize, "TERM", s->term);
1271 child_set_env(&env, &envsize, "DISPLAY", s->display);
1272 if (original_command)
1273 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1277 if (cray_tmpdir[0] != '\0')
1278 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1279 #endif /* _UNICOS */
1282 * Since we clear KRB5CCNAME at startup, if it's set now then it
1283 * must have been set by a native authentication method (eg AIX or
1284 * SIA), so copy it to the child.
1289 if ((cp = getenv("KRB5CCNAME")) != NULL)
1290 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1297 if ((cp = getenv("AUTHSTATE")) != NULL)
1298 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1299 read_environment_file(&env, &envsize, "/etc/environment");
1303 if (s->authctxt->krb5_ccname)
1304 child_set_env(&env, &envsize, "KRB5CCNAME",
1305 s->authctxt->krb5_ccname);
1309 * Pull in any environment variables that may have
1312 if (options.use_pam) {
1315 p = fetch_pam_child_environment();
1316 copy_environment(p, &env, &envsize);
1317 free_pam_environment(p);
1319 p = fetch_pam_environment();
1320 copy_environment(p, &env, &envsize);
1321 free_pam_environment(p);
1323 #endif /* USE_PAM */
1325 if (auth_sock_name != NULL)
1326 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1329 /* read $HOME/.ssh/environment. */
1330 if (options.permit_user_env && !options.use_login) {
1331 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1332 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1333 read_environment_file(&env, &envsize, buf);
1336 /* dump the environment */
1337 fprintf(stderr, "Environment:\n");
1338 for (i = 0; env[i]; i++)
1339 fprintf(stderr, " %.200s\n", env[i]);
1342 *env_size = envsize;
1347 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1348 * first in this order).
1351 do_rc_files(Session *s, const char *shell, char **env, int *env_size)
1359 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1361 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1362 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1363 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1364 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1365 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1367 fprintf(stderr, "Running %s\n", cmd);
1368 f = popen(cmd, "w");
1371 fprintf(f, "%s %s\n", s->auth_proto,
1375 fprintf(stderr, "Could not run %s\n",
1377 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1379 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1380 _PATH_SSH_SYSTEM_RC);
1381 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1384 fprintf(f, "%s %s\n", s->auth_proto,
1388 fprintf(stderr, "Could not run %s\n",
1389 _PATH_SSH_SYSTEM_RC);
1390 } else if (do_xauth && options.xauth_location != NULL) {
1391 /* Add authority data to .Xauthority if appropriate. */
1394 "Running %.500s remove %.100s\n",
1395 options.xauth_location, s->auth_display);
1397 "%.500s add %.100s %.100s %.100s\n",
1398 options.xauth_location, s->auth_display,
1399 s->auth_proto, s->auth_data);
1401 snprintf(cmd, sizeof cmd, "%s -q -",
1402 options.xauth_location);
1403 f = popen(cmd, "w");
1405 char hostname[MAXHOSTNAMELEN];
1407 fprintf(f, "remove %s\n",
1409 fprintf(f, "add %s %s %s\n",
1410 s->auth_display, s->auth_proto,
1413 if (gethostname(hostname,sizeof(hostname)) >= 0)
1414 child_set_env(&env,env_size,"XAUTHLOCALHOSTNAME",
1417 debug("Cannot set up XAUTHLOCALHOSTNAME %s\n",
1420 fprintf(stderr, "Could not run %s\n",
1427 do_nologin(struct passwd *pw)
1430 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1433 #ifdef HAVE_LOGIN_CAP
1434 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1436 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1438 if (pw->pw_uid == 0)
1442 if (stat(nl, &sb) == -1) {
1448 /* /etc/nologin exists. Print its contents if we can and exit. */
1449 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1450 if ((f = fopen(nl, "r")) != NULL) {
1451 while (fgets(buf, sizeof(buf), f))
1459 * Chroot into a directory after checking it for safety: all path components
1460 * must be root-owned directories with strict permissions.
1463 safely_chroot(const char *path, uid_t uid)
1466 char component[MAXPATHLEN];
1470 fatal("chroot path does not begin at root");
1471 if (strlen(path) >= sizeof(component))
1472 fatal("chroot path too long");
1475 * Descend the path, checking that each component is a
1476 * root-owned directory with strict permissions.
1478 for (cp = path; cp != NULL;) {
1479 if ((cp = strchr(cp, '/')) == NULL)
1480 strlcpy(component, path, sizeof(component));
1483 memcpy(component, path, cp - path);
1484 component[cp - path] = '\0';
1487 debug3("%s: checking '%s'", __func__, component);
1489 if (stat(component, &st) != 0)
1490 fatal("%s: stat(\"%s\"): %s", __func__,
1491 component, strerror(errno));
1492 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1493 fatal("bad ownership or modes for chroot "
1494 "directory %s\"%s\"",
1495 cp == NULL ? "" : "component ", component);
1496 if (!S_ISDIR(st.st_mode))
1497 fatal("chroot path %s\"%s\" is not a directory",
1498 cp == NULL ? "" : "component ", component);
1502 if (chdir(path) == -1)
1503 fatal("Unable to chdir to chroot path \"%s\": "
1504 "%s", path, strerror(errno));
1505 if (chroot(path) == -1)
1506 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1507 if (chdir("/") == -1)
1508 fatal("%s: chdir(/) after chroot: %s",
1509 __func__, strerror(errno));
1510 verbose("Changed root directory to \"%s\"", path);
1513 /* Set login name, uid, gid, and groups. */
1515 do_setusercontext(struct passwd *pw)
1517 char *chroot_path, *tmp;
1519 platform_setusercontext(pw);
1521 if (platform_privileged_uidswap()) {
1522 #ifdef HAVE_LOGIN_CAP
1523 if (setusercontext(lc, pw, pw->pw_uid,
1524 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1525 perror("unable to set user context");
1529 if (setlogin(pw->pw_name) < 0)
1530 error("setlogin failed: %s", strerror(errno));
1531 if (setgid(pw->pw_gid) < 0) {
1535 /* Initialize the group list. */
1536 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1537 perror("initgroups");
1543 platform_setusercontext_post_groups(pw);
1545 if (options.chroot_directory != NULL &&
1546 strcasecmp(options.chroot_directory, "none") != 0) {
1547 tmp = tilde_expand_filename(options.chroot_directory,
1549 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1550 "u", pw->pw_name, (char *)NULL);
1551 safely_chroot(chroot_path, pw->pw_uid);
1554 /* Make sure we don't attempt to chroot again */
1555 free(options.chroot_directory);
1556 options.chroot_directory = NULL;
1559 #ifdef HAVE_LOGIN_CAP
1560 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1561 perror("unable to set user context (setuser)");
1565 * FreeBSD's setusercontext() will not apply the user's
1566 * own umask setting unless running with the user's UID.
1568 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK);
1571 if (set_id(pw->pw_name) != 0) {
1572 fatal("set_id(%s) Failed", pw->pw_name);
1574 # endif /* USE_LIBIAF */
1575 /* Permanently switch to the desired uid. */
1576 permanently_set_uid(pw);
1578 } else if (options.chroot_directory != NULL &&
1579 strcasecmp(options.chroot_directory, "none") != 0) {
1580 fatal("server lacks privileges to chroot to ChrootDirectory");
1583 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1584 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1588 do_pwchange(Session *s)
1591 fprintf(stderr, "WARNING: Your password has expired.\n");
1592 if (s->ttyfd != -1) {
1594 "You must change your password now and login again!\n");
1598 #ifdef PASSWD_NEEDS_USERNAME
1599 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1602 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1607 "Password change required but no TTY available.\n");
1613 launch_login(struct passwd *pw, const char *hostname)
1615 /* Launch login(1). */
1617 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1618 #ifdef xxxLOGIN_NEEDS_TERM
1619 (s->term ? s->term : "unknown"),
1620 #endif /* LOGIN_NEEDS_TERM */
1621 #ifdef LOGIN_NO_ENDOPT
1622 "-p", "-f", pw->pw_name, (char *)NULL);
1624 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1627 /* Login couldn't be executed, die. */
1634 child_close_fds(void)
1636 extern AuthenticationConnection *auth_conn;
1639 ssh_close_authentication_connection(auth_conn);
1643 if (packet_get_connection_in() == packet_get_connection_out())
1644 close(packet_get_connection_in());
1646 close(packet_get_connection_in());
1647 close(packet_get_connection_out());
1650 * Close all descriptors related to channels. They will still remain
1651 * open in the parent.
1653 /* XXX better use close-on-exec? -markus */
1654 channel_close_all();
1657 * Close any extra file descriptors. Note that there may still be
1658 * descriptors left by system functions. They will be closed later.
1663 * Close any extra open file descriptors so that we don't have them
1664 * hanging around in clients. Note that we want to do this after
1665 * initgroups, because at least on Solaris 2.3 it leaves file
1668 closefrom(STDERR_FILENO + 1);
1672 * Performs common processing for the child, such as setting up the
1673 * environment, closing extra file descriptors, setting the user and group
1674 * ids, and executing the command or shell.
1678 do_child(Session *s, const char *command)
1680 extern char **environ;
1683 char *argv[ARGV_MAX];
1684 const char *shell, *shell0, *hostname = NULL;
1685 struct passwd *pw = s->pw;
1688 /* remove hostkey from the child's memory */
1689 destroy_sensitive_data();
1691 /* Force a password change */
1692 if (s->authctxt->force_pwchange) {
1693 do_setusercontext(pw);
1699 /* login(1) is only called if we execute the login shell */
1700 if (options.use_login && command != NULL)
1701 options.use_login = 0;
1704 cray_setup(pw->pw_uid, pw->pw_name, command);
1705 #endif /* _UNICOS */
1708 * Login(1) does this as well, and it needs uid 0 for the "-h"
1709 * switch, so we let login(1) to this for us.
1711 if (!options.use_login) {
1713 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1714 if (!check_quietlogin(s, command))
1716 #else /* HAVE_OSF_SIA */
1717 /* When PAM is enabled we rely on it to do the nologin check */
1718 if (!options.use_pam)
1720 do_setusercontext(pw);
1722 * PAM session modules in do_setusercontext may have
1723 * generated messages, so if this in an interactive
1724 * login then display them too.
1726 if (!check_quietlogin(s, command))
1728 #endif /* HAVE_OSF_SIA */
1732 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1733 debug3("PAM session not opened, exiting");
1740 * Get the shell from the password data. An empty shell field is
1741 * legal, and means /bin/sh.
1743 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1746 * Make sure $SHELL points to the shell from the password file,
1747 * even if shell is overridden from login.conf
1749 env = do_setup_env(s, shell, &env_size);
1751 #ifdef HAVE_LOGIN_CAP
1752 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1755 /* we have to stash the hostname before we close our socket. */
1756 if (options.use_login)
1757 hostname = get_remote_name_or_ip(utmp_len,
1760 * Close the connection descriptors; note that this is the child, and
1761 * the server will still have the socket open, and it is important
1762 * that we do not shutdown it. Note that the descriptors cannot be
1763 * closed before building the environment, as we call
1764 * get_remote_ipaddr there.
1769 * Must take new environment into use so that .ssh/rc,
1770 * /etc/ssh/sshrc and xauth are run in the proper environment.
1774 #if defined(KRB5) && defined(USE_AFS)
1776 * At this point, we check to see if AFS is active and if we have
1777 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1778 * if we can (and need to) extend the ticket into an AFS token. If
1779 * we don't do this, we run into potential problems if the user's
1780 * home directory is in AFS and it's not world-readable.
1783 if (options.kerberos_get_afs_token && k_hasafs() &&
1784 (s->authctxt->krb5_ctx != NULL)) {
1787 debug("Getting AFS token");
1791 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1792 krb5_afslog(s->authctxt->krb5_ctx,
1793 s->authctxt->krb5_fwd_ccache, cell, NULL);
1795 krb5_afslog_home(s->authctxt->krb5_ctx,
1796 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1800 /* Change current directory to the user's home directory. */
1801 if (chdir(pw->pw_dir) < 0) {
1802 /* Suppress missing homedir warning for chroot case */
1803 #ifdef HAVE_LOGIN_CAP
1804 r = login_getcapbool(lc, "requirehome", 0);
1806 if (r || options.chroot_directory == NULL ||
1807 strcasecmp(options.chroot_directory, "none") == 0)
1808 fprintf(stderr, "Could not chdir to home "
1809 "directory %s: %s\n", pw->pw_dir,
1815 closefrom(STDERR_FILENO + 1);
1817 if (!options.use_login)
1818 do_rc_files(s, shell, env, &env_size);
1820 /* restore SIGPIPE for child */
1821 signal(SIGPIPE, SIG_DFL);
1823 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1824 printf("This service allows sftp connections only.\n");
1827 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1828 extern int optind, optreset;
1832 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1833 args = xstrdup(command ? command : "sftp-server");
1834 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1835 if (i < ARGV_MAX - 1)
1838 optind = optreset = 1;
1839 __progname = argv[0];
1841 ssh_selinux_change_context("sftpd_t");
1843 exit(sftp_server_main(i, argv, s->pw));
1848 if (options.use_login) {
1849 launch_login(pw, hostname);
1853 /* Get the last component of the shell name. */
1854 if ((shell0 = strrchr(shell, '/')) != NULL)
1860 * If we have no command, execute the shell. In this case, the shell
1861 * name to be passed in argv[0] is preceded by '-' to indicate that
1862 * this is a login shell.
1867 /* Start the shell. Set initial character to '-'. */
1870 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1871 >= sizeof(argv0) - 1) {
1877 /* Execute the shell. */
1880 execve(shell, argv, env);
1882 /* Executing the shell failed. */
1887 * Execute the command using the user's shell. This uses the -c
1888 * option to execute the command.
1890 argv[0] = (char *) shell0;
1892 argv[2] = (char *) command;
1894 execve(shell, argv, env);
1900 session_unused(int id)
1902 debug3("%s: session id %d unused", __func__, id);
1903 if (id >= options.max_sessions ||
1904 id >= sessions_nalloc) {
1905 fatal("%s: insane session id %d (max %d nalloc %d)",
1906 __func__, id, options.max_sessions, sessions_nalloc);
1908 memset(&sessions[id], 0, sizeof(*sessions));
1909 sessions[id].self = id;
1910 sessions[id].used = 0;
1911 sessions[id].chanid = -1;
1912 sessions[id].ptyfd = -1;
1913 sessions[id].ttyfd = -1;
1914 sessions[id].ptymaster = -1;
1915 sessions[id].x11_chanids = NULL;
1916 sessions[id].next_unused = sessions_first_unused;
1917 sessions_first_unused = id;
1925 if (sessions_first_unused == -1) {
1926 if (sessions_nalloc >= options.max_sessions)
1928 debug2("%s: allocate (allocated %d max %d)",
1929 __func__, sessions_nalloc, options.max_sessions);
1930 tmp = xrealloc(sessions, sessions_nalloc + 1,
1933 error("%s: cannot allocate %d sessions",
1934 __func__, sessions_nalloc + 1);
1938 session_unused(sessions_nalloc++);
1941 if (sessions_first_unused >= sessions_nalloc ||
1942 sessions_first_unused < 0) {
1943 fatal("%s: insane first_unused %d max %d nalloc %d",
1944 __func__, sessions_first_unused, options.max_sessions,
1948 s = &sessions[sessions_first_unused];
1950 fatal("%s: session %d already used",
1951 __func__, sessions_first_unused);
1953 sessions_first_unused = s->next_unused;
1955 s->next_unused = -1;
1956 debug("session_new: session %d", s->self);
1965 for (i = 0; i < sessions_nalloc; i++) {
1966 Session *s = &sessions[i];
1968 debug("dump: used %d next_unused %d session %d %p "
1969 "channel %d pid %ld",
1980 session_open(Authctxt *authctxt, int chanid)
1982 Session *s = session_new();
1983 debug("session_open: channel %d", chanid);
1985 error("no more sessions");
1988 s->authctxt = authctxt;
1989 s->pw = authctxt->pw;
1990 if (s->pw == NULL || !authctxt->valid)
1991 fatal("no user for session %d", s->self);
1992 debug("session_open: session %d: link with channel %d", s->self, chanid);
1998 session_by_tty(char *tty)
2001 for (i = 0; i < sessions_nalloc; i++) {
2002 Session *s = &sessions[i];
2003 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2004 debug("session_by_tty: session %d tty %s", i, tty);
2008 debug("session_by_tty: unknown tty %.100s", tty);
2014 session_by_channel(int id)
2017 for (i = 0; i < sessions_nalloc; i++) {
2018 Session *s = &sessions[i];
2019 if (s->used && s->chanid == id) {
2020 debug("session_by_channel: session %d channel %d",
2025 debug("session_by_channel: unknown channel %d", id);
2031 session_by_x11_channel(int id)
2035 for (i = 0; i < sessions_nalloc; i++) {
2036 Session *s = &sessions[i];
2038 if (s->x11_chanids == NULL || !s->used)
2040 for (j = 0; s->x11_chanids[j] != -1; j++) {
2041 if (s->x11_chanids[j] == id) {
2042 debug("session_by_x11_channel: session %d "
2043 "channel %d", s->self, id);
2048 debug("session_by_x11_channel: unknown channel %d", id);
2054 session_by_pid(pid_t pid)
2057 debug("session_by_pid: pid %ld", (long)pid);
2058 for (i = 0; i < sessions_nalloc; i++) {
2059 Session *s = &sessions[i];
2060 if (s->used && s->pid == pid)
2063 error("session_by_pid: unknown pid %ld", (long)pid);
2069 session_window_change_req(Session *s)
2071 s->col = packet_get_int();
2072 s->row = packet_get_int();
2073 s->xpixel = packet_get_int();
2074 s->ypixel = packet_get_int();
2076 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2081 session_pty_req(Session *s)
2086 if (no_pty_flag || !options.permit_tty) {
2087 debug("Allocating a pty not permitted for this authentication.");
2090 if (s->ttyfd != -1) {
2091 packet_disconnect("Protocol error: you already have a pty.");
2095 s->term = packet_get_string(&len);
2098 s->col = packet_get_int();
2099 s->row = packet_get_int();
2101 s->row = packet_get_int();
2102 s->col = packet_get_int();
2104 s->xpixel = packet_get_int();
2105 s->ypixel = packet_get_int();
2107 if (strcmp(s->term, "") == 0) {
2112 /* Allocate a pty and open it. */
2113 debug("Allocating pty.");
2114 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2120 error("session_pty_req: session %d alloc failed", s->self);
2123 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2125 /* for SSH1 the tty modes length is not given */
2127 n_bytes = packet_remaining();
2128 tty_parse_modes(s->ttyfd, &n_bytes);
2131 pty_setowner(s->pw, s->tty);
2133 /* Set window size from the packet. */
2134 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2137 session_proctitle(s);
2142 session_subsystem_req(Session *s)
2150 s->subsys = packet_get_string(&len);
2152 debug2("subsystem request for %.100s by user %s", s->subsys,
2155 for (i = 0; i < options.num_subsystems; i++) {
2156 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
2157 prog = options.subsystem_command[i];
2158 cmd = options.subsystem_args[i];
2159 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2160 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2161 debug("subsystem: %s", prog);
2163 if (stat(prog, &st) < 0)
2164 debug("subsystem: cannot stat %s: %s",
2165 prog, strerror(errno));
2166 s->is_subsystem = SUBSYSTEM_EXT;
2167 debug("subsystem: exec() %s", cmd);
2169 success = do_exec(s, cmd) == 0;
2175 logit("subsystem request for %.100s by user %s failed, "
2176 "subsystem not found", s->subsys, s->pw->pw_name);
2182 session_x11_req(Session *s)
2186 if (s->auth_proto != NULL || s->auth_data != NULL) {
2187 error("session_x11_req: session %d: "
2188 "x11 forwarding already active", s->self);
2191 s->single_connection = packet_get_char();
2192 s->auth_proto = packet_get_string(NULL);
2193 s->auth_data = packet_get_string(NULL);
2194 s->screen = packet_get_int();
2197 success = session_setup_x11fwd(s);
2199 free(s->auth_proto);
2201 s->auth_proto = NULL;
2202 s->auth_data = NULL;
2208 session_shell_req(Session *s)
2211 return do_exec(s, NULL) == 0;
2215 session_exec_req(Session *s)
2219 char *command = packet_get_string(&len);
2221 success = do_exec(s, command) == 0;
2227 session_break_req(Session *s)
2230 packet_get_int(); /* ignored */
2233 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2239 session_env_req(Session *s)
2242 u_int name_len, val_len, i;
2244 name = packet_get_cstring(&name_len);
2245 val = packet_get_cstring(&val_len);
2248 /* Don't set too many environment variables */
2249 if (s->num_env > 128) {
2250 debug2("Ignoring env request %s: too many env vars", name);
2254 for (i = 0; i < options.num_accept_env; i++) {
2255 if (match_pattern(name, options.accept_env[i])) {
2256 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2257 s->env = xrealloc(s->env, s->num_env + 1,
2259 s->env[s->num_env].name = name;
2260 s->env[s->num_env].val = val;
2265 debug2("Ignoring env request %s: disallowed name", name);
2274 session_auth_agent_req(Session *s)
2276 static int called = 0;
2278 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2279 debug("session_auth_agent_req: no_agent_forwarding_flag");
2286 return auth_input_request_forwarding(s->pw);
2291 session_input_channel_req(Channel *c, const char *rtype)
2296 if ((s = session_by_channel(c->self)) == NULL) {
2297 logit("session_input_channel_req: no session %d req %.100s",
2301 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2304 * a session is in LARVAL state until a shell, a command
2305 * or a subsystem is executed
2307 if (c->type == SSH_CHANNEL_LARVAL) {
2308 if (strcmp(rtype, "shell") == 0) {
2309 success = session_shell_req(s);
2310 } else if (strcmp(rtype, "exec") == 0) {
2311 success = session_exec_req(s);
2312 } else if (strcmp(rtype, "pty-req") == 0) {
2313 success = session_pty_req(s);
2314 } else if (strcmp(rtype, "x11-req") == 0) {
2315 success = session_x11_req(s);
2316 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2317 success = session_auth_agent_req(s);
2318 } else if (strcmp(rtype, "subsystem") == 0) {
2319 success = session_subsystem_req(s);
2320 } else if (strcmp(rtype, "env") == 0) {
2321 success = session_env_req(s);
2324 if (strcmp(rtype, "window-change") == 0) {
2325 success = session_window_change_req(s);
2326 } else if (strcmp(rtype, "break") == 0) {
2327 success = session_break_req(s);
2334 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2338 fatal("session_set_fds: called for proto != 2.0");
2340 * now that have a child and a pipe to the child,
2341 * we can activate our channel and register the fd's
2343 if (s->chanid == -1)
2344 fatal("no channel for session %d", s->self);
2345 channel_set_fds(s->chanid,
2347 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2348 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2352 * Function to perform pty cleanup. Also called if we get aborted abnormally
2353 * (e.g., due to a dropped connection).
2356 session_pty_cleanup2(Session *s)
2359 error("session_pty_cleanup: no session");
2365 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2367 /* Record that the user has logged out. */
2369 record_logout(s->pid, s->tty, s->pw->pw_name);
2371 /* Release the pseudo-tty. */
2373 pty_release(s->tty);
2376 * Close the server side of the socket pairs. We must do this after
2377 * the pty cleanup, so that another process doesn't get this pty
2378 * while we're still cleaning up.
2380 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2381 error("close(s->ptymaster/%d): %s",
2382 s->ptymaster, strerror(errno));
2384 /* unlink pty from session */
2389 session_pty_cleanup(Session *s)
2391 PRIVSEP(session_pty_cleanup2(s));
2397 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2412 return "SIG@openssh.com";
2416 session_close_x11(int id)
2420 if ((c = channel_by_id(id)) == NULL) {
2421 debug("session_close_x11: x11 channel %d missing", id);
2423 /* Detach X11 listener */
2424 debug("session_close_x11: detach x11 channel %d", id);
2425 channel_cancel_cleanup(id);
2426 if (c->ostate != CHAN_OUTPUT_CLOSED)
2432 session_close_single_x11(int id, void *arg)
2437 debug3("session_close_single_x11: channel %d", id);
2438 channel_cancel_cleanup(id);
2439 if ((s = session_by_x11_channel(id)) == NULL)
2440 fatal("session_close_single_x11: no x11 channel %d", id);
2441 for (i = 0; s->x11_chanids[i] != -1; i++) {
2442 debug("session_close_single_x11: session %d: "
2443 "closing channel %d", s->self, s->x11_chanids[i]);
2445 * The channel "id" is already closing, but make sure we
2446 * close all of its siblings.
2448 if (s->x11_chanids[i] != id)
2449 session_close_x11(s->x11_chanids[i]);
2451 free(s->x11_chanids);
2452 s->x11_chanids = NULL;
2455 free(s->auth_proto);
2456 s->auth_proto = NULL;
2458 s->auth_data = NULL;
2459 free(s->auth_display);
2460 s->auth_display = NULL;
2464 session_exit_message(Session *s, int status)
2468 if ((c = channel_lookup(s->chanid)) == NULL)
2469 fatal("session_exit_message: session %d: no channel %d",
2470 s->self, s->chanid);
2471 debug("session_exit_message: session %d channel %d pid %ld",
2472 s->self, s->chanid, (long)s->pid);
2474 if (WIFEXITED(status)) {
2475 channel_request_start(s->chanid, "exit-status", 0);
2476 packet_put_int(WEXITSTATUS(status));
2478 } else if (WIFSIGNALED(status)) {
2479 channel_request_start(s->chanid, "exit-signal", 0);
2480 packet_put_cstring(sig2name(WTERMSIG(status)));
2482 packet_put_char(WCOREDUMP(status)? 1 : 0);
2483 #else /* WCOREDUMP */
2485 #endif /* WCOREDUMP */
2486 packet_put_cstring("");
2487 packet_put_cstring("");
2490 /* Some weird exit cause. Just exit. */
2491 packet_disconnect("wait returned status %04x.", status);
2494 /* disconnect channel */
2495 debug("session_exit_message: release channel %d", s->chanid);
2498 * Adjust cleanup callback attachment to send close messages when
2499 * the channel gets EOF. The session will be then be closed
2500 * by session_close_by_channel when the childs close their fds.
2502 channel_register_cleanup(c->self, session_close_by_channel, 1);
2505 * emulate a write failure with 'chan_write_failed', nobody will be
2506 * interested in data we write.
2507 * Note that we must not call 'chan_read_failed', since there could
2508 * be some more data waiting in the pipe.
2510 if (c->ostate != CHAN_OUTPUT_CLOSED)
2511 chan_write_failed(c);
2515 session_close(Session *s)
2519 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2521 session_pty_cleanup(s);
2524 free(s->x11_chanids);
2525 free(s->auth_display);
2527 free(s->auth_proto);
2529 if (s->env != NULL) {
2530 for (i = 0; i < s->num_env; i++) {
2531 free(s->env[i].name);
2532 free(s->env[i].val);
2536 session_proctitle(s);
2537 session_unused(s->self);
2541 session_close_by_pid(pid_t pid, int status)
2543 Session *s = session_by_pid(pid);
2545 debug("session_close_by_pid: no session for pid %ld",
2549 if (s->chanid != -1)
2550 session_exit_message(s, status);
2552 session_pty_cleanup(s);
2557 * this is called when a channel dies before
2558 * the session 'child' itself dies
2561 session_close_by_channel(int id, void *arg)
2563 Session *s = session_by_channel(id);
2567 debug("session_close_by_channel: no session for id %d", id);
2570 debug("session_close_by_channel: channel %d child %ld",
2573 debug("session_close_by_channel: channel %d: has child", id);
2575 * delay detach of session, but release pty, since
2576 * the fd's to the child are already closed
2579 session_pty_cleanup(s);
2582 /* detach by removing callback */
2583 channel_cancel_cleanup(s->chanid);
2585 /* Close any X11 listeners associated with this session */
2586 if (s->x11_chanids != NULL) {
2587 for (i = 0; s->x11_chanids[i] != -1; i++) {
2588 session_close_x11(s->x11_chanids[i]);
2589 s->x11_chanids[i] = -1;
2598 session_destroy_all(void (*closefunc)(Session *))
2601 for (i = 0; i < sessions_nalloc; i++) {
2602 Session *s = &sessions[i];
2604 if (closefunc != NULL)
2613 session_tty_list(void)
2615 static char buf[1024];
2620 for (i = 0; i < sessions_nalloc; i++) {
2621 Session *s = &sessions[i];
2622 if (s->used && s->ttyfd != -1) {
2624 if (strncmp(s->tty, "/dev/", 5) != 0) {
2625 cp = strrchr(s->tty, '/');
2626 cp = (cp == NULL) ? s->tty : cp + 1;
2631 strlcat(buf, ",", sizeof buf);
2632 strlcat(buf, cp, sizeof buf);
2636 strlcpy(buf, "notty", sizeof buf);
2641 session_proctitle(Session *s)
2644 error("no user for session %d", s->self);
2646 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2650 session_setup_x11fwd(Session *s)
2653 char display[512], auth_display[512];
2654 char hostname[MAXHOSTNAMELEN];
2657 if (no_x11_forwarding_flag) {
2658 packet_send_debug("X11 forwarding disabled in user configuration file.");
2661 if (!options.x11_forwarding) {
2662 debug("X11 forwarding disabled in server configuration file.");
2665 if (!options.xauth_location ||
2666 (stat(options.xauth_location, &st) == -1)) {
2667 packet_send_debug("No xauth program; cannot forward with spoofing.");
2670 if (options.use_login) {
2671 packet_send_debug("X11 forwarding disabled; "
2672 "not compatible with UseLogin=yes.");
2675 if (s->display != NULL) {
2676 debug("X11 display already set.");
2679 if (x11_create_display_inet(options.x11_display_offset,
2680 options.x11_use_localhost, s->single_connection,
2681 &s->display_number, &s->x11_chanids) == -1) {
2682 debug("x11_create_display_inet failed.");
2685 for (i = 0; s->x11_chanids[i] != -1; i++) {
2686 channel_register_cleanup(s->x11_chanids[i],
2687 session_close_single_x11, 0);
2690 /* Set up a suitable value for the DISPLAY variable. */
2691 if (gethostname(hostname, sizeof(hostname)) < 0)
2692 fatal("gethostname: %.100s", strerror(errno));
2694 * auth_display must be used as the displayname when the
2695 * authorization entry is added with xauth(1). This will be
2696 * different than the DISPLAY string for localhost displays.
2698 if (options.x11_use_localhost) {
2699 snprintf(display, sizeof display, "localhost:%u.%u",
2700 s->display_number, s->screen);
2701 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2702 s->display_number, s->screen);
2703 s->display = xstrdup(display);
2704 s->auth_display = xstrdup(auth_display);
2706 #ifdef IPADDR_IN_DISPLAY
2708 struct in_addr my_addr;
2710 he = gethostbyname(hostname);
2712 error("Can't get IP address for X11 DISPLAY.");
2713 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2716 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2717 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2718 s->display_number, s->screen);
2720 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2721 s->display_number, s->screen);
2723 s->display = xstrdup(display);
2724 s->auth_display = xstrdup(display);
2731 do_authenticated2(Authctxt *authctxt)
2733 server_loop2(authctxt);
2737 do_cleanup(Authctxt *authctxt)
2739 static int called = 0;
2741 debug("do_cleanup");
2743 /* no cleanup if we're in the child for login shell */
2747 /* avoid double cleanup */
2752 if (authctxt == NULL)
2756 if (options.use_pam) {
2758 sshpam_thread_cleanup();
2762 if (!authctxt->authenticated)
2766 if (options.kerberos_ticket_cleanup &&
2768 krb5_cleanup_proc(authctxt);
2772 if (compat20 && options.gss_cleanup_creds)
2773 ssh_gssapi_cleanup_creds();
2776 /* remove agent socket */
2777 auth_sock_cleanup_proc(authctxt->pw);
2780 * Cleanup ptys/utmp only if privsep is disabled,
2781 * or if running in monitor.
2783 if (!use_privsep || mm_is_monitor())
2784 session_destroy_all(session_pty_cleanup2);