1 /* $OpenBSD: session.c,v 1.282 2016/03/10 11:47:57 djm Exp $ */
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 #include <sys/types.h>
39 #include <sys/param.h>
40 #ifdef HAVE_SYS_STAT_H
41 # include <sys/stat.h>
43 #include <sys/socket.h>
47 #include <arpa/inet.h>
66 #include "openbsd-compat/sys-queue.h"
85 #include "auth-options.h"
87 #include "pathnames.h"
92 #include "serverloop.h"
96 #include "monitor_wrap.h"
99 #if defined(KRB5) && defined(USE_AFS)
104 #include <selinux/selinux.h>
107 #define IS_INTERNAL_SFTP(c) \
108 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
109 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
110 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
111 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
115 Session *session_new(void);
116 void session_set_fds(Session *, int, int, int, int, int);
117 void session_pty_cleanup(Session *);
118 void session_proctitle(Session *);
119 int session_setup_x11fwd(Session *);
120 int do_exec_pty(Session *, const char *);
121 int do_exec_no_pty(Session *, const char *);
122 int do_exec(Session *, const char *);
123 void do_login(Session *, const char *);
124 #ifdef LOGIN_NEEDS_UTMPX
125 static void do_pre_login(Session *s);
127 void do_child(Session *, const char *);
129 int check_quietlogin(Session *, const char *);
131 static void do_authenticated1(Authctxt *);
132 static void do_authenticated2(Authctxt *);
134 static int session_pty_req(Session *);
137 extern ServerOptions options;
138 extern char *__progname;
139 extern int log_stderr;
140 extern int debug_flag;
141 extern u_int utmp_len;
142 extern int startup_pipe;
143 extern void destroy_sensitive_data(void);
144 extern Buffer loginmsg;
146 /* original command from peer. */
147 const char *original_command = NULL;
150 static int sessions_first_unused = -1;
151 static int sessions_nalloc = 0;
152 static Session *sessions = NULL;
154 #define SUBSYSTEM_NONE 0
155 #define SUBSYSTEM_EXT 1
156 #define SUBSYSTEM_INT_SFTP 2
157 #define SUBSYSTEM_INT_SFTP_ERROR 3
159 #ifdef HAVE_LOGIN_CAP
163 static int is_child = 0;
164 static int in_chroot = 0;
166 /* Name and directory of socket for authentication agent forwarding. */
167 static char *auth_sock_name = NULL;
168 static char *auth_sock_dir = NULL;
170 /* removes the agent forwarding socket */
173 auth_sock_cleanup_proc(struct passwd *pw)
175 if (auth_sock_name != NULL) {
176 temporarily_use_uid(pw);
177 unlink(auth_sock_name);
178 rmdir(auth_sock_dir);
179 auth_sock_name = NULL;
185 auth_input_request_forwarding(struct passwd * pw)
190 if (auth_sock_name != NULL) {
191 error("authentication forwarding requested twice.");
195 /* Temporarily drop privileged uid for mkdir/bind. */
196 temporarily_use_uid(pw);
198 /* Allocate a buffer for the socket name, and format the name. */
199 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
201 /* Create private directory for socket */
202 if (mkdtemp(auth_sock_dir) == NULL) {
203 packet_send_debug("Agent forwarding disabled: "
204 "mkdtemp() failed: %.100s", strerror(errno));
207 auth_sock_dir = NULL;
211 xasprintf(&auth_sock_name, "%s/agent.%ld",
212 auth_sock_dir, (long) getpid());
214 /* Start a Unix listener on auth_sock_name. */
215 sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0);
217 /* Restore the privileged uid. */
220 /* Check for socket/bind/listen failure. */
224 /* Allocate a channel for the authentication agent socket. */
225 nc = channel_new("auth socket",
226 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
227 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
228 0, "auth socket", 1);
229 nc->path = xstrdup(auth_sock_name);
233 free(auth_sock_name);
234 if (auth_sock_dir != NULL) {
235 rmdir(auth_sock_dir);
240 auth_sock_name = NULL;
241 auth_sock_dir = NULL;
246 display_loginmsg(void)
248 if (buffer_len(&loginmsg) > 0) {
249 buffer_append(&loginmsg, "\0", 1);
250 printf("%s", (char *)buffer_ptr(&loginmsg));
251 buffer_clear(&loginmsg);
256 do_authenticated(Authctxt *authctxt)
258 setproctitle("%s", authctxt->pw->pw_name);
260 /* setup the channel layer */
261 /* XXX - streamlocal? */
262 if (no_port_forwarding_flag ||
263 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
264 channel_disable_adm_local_opens();
266 channel_permit_all_opens();
271 do_authenticated2(authctxt);
273 do_authenticated1(authctxt);
275 do_cleanup(authctxt);
278 /* Check untrusted xauth strings for metacharacters */
280 xauth_valid_string(const char *s)
284 for (i = 0; s[i] != '\0'; i++) {
285 if (!isalnum((u_char)s[i]) &&
286 s[i] != '.' && s[i] != ':' && s[i] != '/' &&
287 s[i] != '-' && s[i] != '_')
294 * Prepares for an interactive session. This is called after the user has
295 * been successfully authenticated. During this message exchange, pseudo
296 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
297 * are requested, etc.
300 do_authenticated1(Authctxt *authctxt)
304 int success, type, screen_flag;
305 int enable_compression_after_reply = 0;
306 u_int proto_len, data_len, dlen, compression_level = 0;
310 error("no more sessions");
313 s->authctxt = authctxt;
314 s->pw = authctxt->pw;
317 * We stay in this loop until the client requests to execute a shell
323 /* Get a packet from the client. */
324 type = packet_read();
326 /* Process the packet. */
328 case SSH_CMSG_REQUEST_COMPRESSION:
329 compression_level = packet_get_int();
331 if (compression_level < 1 || compression_level > 9) {
332 packet_send_debug("Received invalid compression level %d.",
336 if (options.compression == COMP_NONE) {
337 debug2("compression disabled");
340 /* Enable compression after we have responded with SUCCESS. */
341 enable_compression_after_reply = 1;
345 case SSH_CMSG_REQUEST_PTY:
346 success = session_pty_req(s);
349 case SSH_CMSG_X11_REQUEST_FORWARDING:
350 s->auth_proto = packet_get_string(&proto_len);
351 s->auth_data = packet_get_string(&data_len);
353 screen_flag = packet_get_protocol_flags() &
354 SSH_PROTOFLAG_SCREEN_NUMBER;
355 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
357 if (packet_remaining() == 4) {
359 debug2("Buggy client: "
360 "X11 screen flag missing");
361 s->screen = packet_get_int();
366 if (xauth_valid_string(s->auth_proto) &&
367 xauth_valid_string(s->auth_data))
368 success = session_setup_x11fwd(s);
371 error("Invalid X11 forwarding data");
376 s->auth_proto = NULL;
381 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
382 if (!options.allow_agent_forwarding ||
383 no_agent_forwarding_flag || compat13) {
384 debug("Authentication agent forwarding not permitted for this authentication.");
387 debug("Received authentication agent forwarding request.");
388 success = auth_input_request_forwarding(s->pw);
391 case SSH_CMSG_PORT_FORWARD_REQUEST:
392 if (no_port_forwarding_flag) {
393 debug("Port forwarding not permitted for this authentication.");
396 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
397 debug("Port forwarding not permitted.");
400 debug("Received TCP/IP port forwarding request.");
401 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
402 &options.fwd_opts) < 0) {
403 debug("Port forwarding failed.");
409 case SSH_CMSG_MAX_PACKET_SIZE:
410 if (packet_set_maxsize(packet_get_int()) > 0)
414 case SSH_CMSG_EXEC_SHELL:
415 case SSH_CMSG_EXEC_CMD:
416 if (type == SSH_CMSG_EXEC_CMD) {
417 command = packet_get_string(&dlen);
418 debug("Exec command '%.500s'", command);
419 if (do_exec(s, command) != 0)
421 "command execution failed");
424 if (do_exec(s, NULL) != 0)
426 "shell execution failed");
434 * Any unknown messages in this phase are ignored,
435 * and a failure message is returned.
437 logit("Unknown packet type received after authentication: %d", type);
439 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
443 /* Enable compression now that we have replied if appropriate. */
444 if (enable_compression_after_reply) {
445 enable_compression_after_reply = 0;
446 packet_start_compression(compression_level);
453 * This is called to fork and execute a command when we have no tty. This
454 * will call do_child from the child, and server_loop from the parent after
455 * setting up file descriptors and such.
458 do_exec_no_pty(Session *s, const char *command)
463 int pin[2], pout[2], perr[2];
466 fatal("do_exec_no_pty: no session");
468 /* Allocate pipes for communicating with the program. */
470 error("%s: pipe in: %.100s", __func__, strerror(errno));
473 if (pipe(pout) < 0) {
474 error("%s: pipe out: %.100s", __func__, strerror(errno));
479 if (pipe(perr) < 0) {
480 error("%s: pipe err: %.100s", __func__,
489 int inout[2], err[2];
492 fatal("do_exec_no_pty: no session");
494 /* Uses socket pairs to communicate with the program. */
495 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
496 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
499 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
500 error("%s: socketpair #2: %.100s", __func__,
508 session_proctitle(s);
510 /* Fork the child. */
511 switch ((pid = fork())) {
513 error("%s: fork: %.100s", __func__, strerror(errno));
531 /* Child. Reinitialize the log since the pid has changed. */
532 log_init(__progname, options.log_level,
533 options.log_facility, log_stderr);
536 * Create a new session and process group since the 4.4BSD
537 * setlogin() affects the entire process group.
540 error("setsid failed: %.100s", strerror(errno));
544 * Redirect stdin. We close the parent side of the socket
545 * pair, and make the child side the standard input.
548 if (dup2(pin[0], 0) < 0)
549 perror("dup2 stdin");
552 /* Redirect stdout. */
554 if (dup2(pout[1], 1) < 0)
555 perror("dup2 stdout");
558 /* Redirect stderr. */
560 if (dup2(perr[1], 2) < 0)
561 perror("dup2 stderr");
565 * Redirect stdin, stdout, and stderr. Stdin and stdout will
566 * use the same socket, as some programs (particularly rdist)
567 * seem to depend on it.
571 if (dup2(inout[0], 0) < 0) /* stdin */
572 perror("dup2 stdin");
573 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
574 perror("dup2 stdout");
576 if (dup2(err[0], 2) < 0) /* stderr */
577 perror("dup2 stderr");
583 cray_init_job(s->pw); /* set up cray jid and tmpdir */
586 /* Do processing for the child (exec command etc). */
587 do_child(s, command);
594 signal(WJSIGNAL, cray_job_termination_handler);
597 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
601 /* Set interactive/non-interactive mode. */
602 packet_set_interactive(s->display != NULL,
603 options.ip_qos_interactive, options.ip_qos_bulk);
606 * Clear loginmsg, since it's the child's responsibility to display
607 * it to the user, otherwise multiple sessions may accumulate
608 * multiple copies of the login messages.
610 buffer_clear(&loginmsg);
613 /* We are the parent. Close the child sides of the pipes. */
619 session_set_fds(s, pin[1], pout[0], perr[0],
622 /* Enter the interactive session. */
623 server_loop(pid, pin[1], pout[0], perr[0]);
624 /* server_loop has closed pin[1], pout[0], and perr[0]. */
627 /* We are the parent. Close the child sides of the socket pairs. */
632 * Enter the interactive session. Note: server_loop must be able to
633 * handle the case that fdin and fdout are the same.
636 session_set_fds(s, inout[1], inout[1], err[1],
639 server_loop(pid, inout[1], inout[1], err[1]);
640 /* server_loop has closed inout[1] and err[1]. */
647 * This is called to fork and execute a command when we have a tty. This
648 * will call do_child from the child, and server_loop from the parent after
649 * setting up file descriptors, controlling tty, updating wtmp, utmp,
650 * lastlog, and other such operations.
653 do_exec_pty(Session *s, const char *command)
655 int fdout, ptyfd, ttyfd, ptymaster;
659 fatal("do_exec_pty: no session");
664 * Create another descriptor of the pty master side for use as the
665 * standard input. We could use the original descriptor, but this
666 * simplifies code in server_loop. The descriptor is bidirectional.
667 * Do this before forking (and cleanup in the child) so as to
668 * detect and gracefully fail out-of-fd conditions.
670 if ((fdout = dup(ptyfd)) < 0) {
671 error("%s: dup #1: %s", __func__, strerror(errno));
676 /* we keep a reference to the pty master */
677 if ((ptymaster = dup(ptyfd)) < 0) {
678 error("%s: dup #2: %s", __func__, strerror(errno));
685 /* Fork the child. */
686 switch ((pid = fork())) {
688 error("%s: fork: %.100s", __func__, strerror(errno));
700 /* Child. Reinitialize the log because the pid has changed. */
701 log_init(__progname, options.log_level,
702 options.log_facility, log_stderr);
703 /* Close the master side of the pseudo tty. */
706 /* Make the pseudo tty our controlling tty. */
707 pty_make_controlling_tty(&ttyfd, s->tty);
709 /* Redirect stdin/stdout/stderr from the pseudo tty. */
710 if (dup2(ttyfd, 0) < 0)
711 error("dup2 stdin: %s", strerror(errno));
712 if (dup2(ttyfd, 1) < 0)
713 error("dup2 stdout: %s", strerror(errno));
714 if (dup2(ttyfd, 2) < 0)
715 error("dup2 stderr: %s", strerror(errno));
717 /* Close the extra descriptor for the pseudo tty. */
720 /* record login, etc. similar to login(1) */
722 if (!(options.use_login && command == NULL)) {
724 cray_init_job(s->pw); /* set up cray jid and tmpdir */
726 do_login(s, command);
728 # ifdef LOGIN_NEEDS_UTMPX
734 * Do common processing for the child, such as execing
737 do_child(s, command);
744 signal(WJSIGNAL, cray_job_termination_handler);
747 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
752 /* Parent. Close the slave side of the pseudo tty. */
755 /* Enter interactive session. */
756 s->ptymaster = ptymaster;
757 packet_set_interactive(1,
758 options.ip_qos_interactive, options.ip_qos_bulk);
760 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
762 server_loop(pid, ptyfd, fdout, -1);
763 /* server_loop _has_ closed ptyfd and fdout. */
768 #ifdef LOGIN_NEEDS_UTMPX
770 do_pre_login(Session *s)
772 struct ssh *ssh = active_state; /* XXX */
774 struct sockaddr_storage from;
775 pid_t pid = getpid();
778 * Get IP address of client. If the connection is not a socket, let
779 * the address be 0.0.0.0.
781 memset(&from, 0, sizeof(from));
782 fromlen = sizeof(from);
783 if (packet_connection_is_on_socket()) {
784 if (getpeername(packet_get_connection_in(),
785 (struct sockaddr *)&from, &fromlen) < 0) {
786 debug("getpeername: %.100s", strerror(errno));
791 record_utmp_only(pid, s->tty, s->pw->pw_name,
792 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns),
793 (struct sockaddr *)&from, fromlen);
798 * This is called to fork and execute a command. If another command is
799 * to be forced, execute that instead.
802 do_exec(Session *s, const char *command)
804 struct ssh *ssh = active_state; /* XXX */
806 const char *forced = NULL, *tty = NULL;
807 char session_type[1024];
809 if (options.adm_forced_command) {
810 original_command = command;
811 command = options.adm_forced_command;
813 } else if (forced_command) {
814 original_command = command;
815 command = forced_command;
816 forced = "(key-option)";
818 if (forced != NULL) {
819 if (IS_INTERNAL_SFTP(command)) {
820 s->is_subsystem = s->is_subsystem ?
821 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
822 } else if (s->is_subsystem)
823 s->is_subsystem = SUBSYSTEM_EXT;
824 snprintf(session_type, sizeof(session_type),
825 "forced-command %s '%.900s'", forced, command);
826 } else if (s->is_subsystem) {
827 snprintf(session_type, sizeof(session_type),
828 "subsystem '%.900s'", s->subsys);
829 } else if (command == NULL) {
830 snprintf(session_type, sizeof(session_type), "shell");
832 /* NB. we don't log unforced commands to preserve privacy */
833 snprintf(session_type, sizeof(session_type), "command");
836 if (s->ttyfd != -1) {
838 if (strncmp(tty, "/dev/", 5) == 0)
842 verbose("Starting session: %s%s%s for %s from %.200s port %d id %d",
844 tty == NULL ? "" : " on ",
845 tty == NULL ? "" : tty,
847 ssh_remote_ipaddr(ssh),
848 ssh_remote_port(ssh),
851 #ifdef SSH_AUDIT_EVENTS
853 PRIVSEP(audit_run_command(command));
854 else if (s->ttyfd == -1) {
855 char *shell = s->pw->pw_shell;
857 if (shell[0] == '\0') /* empty shell means /bin/sh */
859 PRIVSEP(audit_run_command(shell));
863 ret = do_exec_pty(s, command);
865 ret = do_exec_no_pty(s, command);
867 original_command = NULL;
870 * Clear loginmsg: it's the child's responsibility to display
871 * it to the user, otherwise multiple sessions may accumulate
872 * multiple copies of the login messages.
874 buffer_clear(&loginmsg);
879 /* administrative, login(1)-like work */
881 do_login(Session *s, const char *command)
883 struct ssh *ssh = active_state; /* XXX */
885 struct sockaddr_storage from;
886 struct passwd * pw = s->pw;
887 pid_t pid = getpid();
890 * Get IP address of client. If the connection is not a socket, let
891 * the address be 0.0.0.0.
893 memset(&from, 0, sizeof(from));
894 fromlen = sizeof(from);
895 if (packet_connection_is_on_socket()) {
896 if (getpeername(packet_get_connection_in(),
897 (struct sockaddr *)&from, &fromlen) < 0) {
898 debug("getpeername: %.100s", strerror(errno));
903 /* Record that there was a login on that tty from the remote host. */
905 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
906 session_get_remote_name_or_ip(ssh, utmp_len,
908 (struct sockaddr *)&from, fromlen);
912 * If password change is needed, do it now.
913 * This needs to occur before the ~/.hushlogin check.
915 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
918 s->authctxt->force_pwchange = 0;
919 /* XXX - signal [net] parent to enable forwardings */
923 if (check_quietlogin(s, command))
932 * Display the message of the day.
940 if (options.print_motd) {
941 #ifdef HAVE_LOGIN_CAP
942 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
945 f = fopen("/etc/motd", "r");
948 while (fgets(buf, sizeof(buf), f))
957 * Check for quiet login, either .hushlogin or command given.
960 check_quietlogin(Session *s, const char *command)
963 struct passwd *pw = s->pw;
966 /* Return 1 if .hushlogin exists or a command given. */
969 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
970 #ifdef HAVE_LOGIN_CAP
971 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
974 if (stat(buf, &st) >= 0)
981 * Sets the value of the given variable in the environment. If the variable
982 * already exists, its value is overridden.
985 child_set_env(char ***envp, u_int *envsizep, const char *name,
992 if (strchr(name, '=') != NULL) {
993 error("Invalid environment variable \"%.100s\"", name);
998 * If we're passed an uninitialized list, allocate a single null
999 * entry before continuing.
1001 if (*envp == NULL && *envsizep == 0) {
1002 *envp = xmalloc(sizeof(char *));
1008 * Find the slot where the value should be stored. If the variable
1009 * already exists, we reuse the slot; otherwise we append a new slot
1010 * at the end of the array, expanding if necessary.
1013 namelen = strlen(name);
1014 for (i = 0; env[i]; i++)
1015 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1018 /* Reuse the slot. */
1021 /* New variable. Expand if necessary. */
1022 envsize = *envsizep;
1023 if (i >= envsize - 1) {
1024 if (envsize >= 1000)
1025 fatal("child_set_env: too many env vars");
1027 env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
1028 *envsizep = envsize;
1030 /* Need to set the NULL pointer at end of array beyond the new slot. */
1034 /* Allocate space and format the variable in the appropriate slot. */
1035 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1036 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1040 * Reads environment variables from the given file and adds/overrides them
1041 * into the environment. If the file does not exist, this does nothing.
1042 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1043 * and assignments of the form name=value. No other forms are allowed.
1046 read_environment_file(char ***env, u_int *envsize,
1047 const char *filename)
1054 f = fopen(filename, "r");
1058 while (fgets(buf, sizeof(buf), f)) {
1059 if (++lineno > 1000)
1060 fatal("Too many lines in environment file %s", filename);
1061 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1063 if (!*cp || *cp == '#' || *cp == '\n')
1066 cp[strcspn(cp, "\n")] = '\0';
1068 value = strchr(cp, '=');
1069 if (value == NULL) {
1070 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1075 * Replace the equals sign by nul, and advance value to
1080 child_set_env(env, envsize, cp, value);
1085 #ifdef HAVE_ETC_DEFAULT_LOGIN
1087 * Return named variable from specified environment, or NULL if not present.
1090 child_get_env(char **env, const char *name)
1096 for (i=0; env[i] != NULL; i++)
1097 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1098 return(env[i] + len + 1);
1103 * Read /etc/default/login.
1104 * We pick up the PATH (or SUPATH for root) and UMASK.
1107 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1109 char **tmpenv = NULL, *var;
1110 u_int i, tmpenvsize = 0;
1114 * We don't want to copy the whole file to the child's environment,
1115 * so we use a temporary environment and copy the variables we're
1118 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1124 var = child_get_env(tmpenv, "SUPATH");
1126 var = child_get_env(tmpenv, "PATH");
1128 child_set_env(env, envsize, "PATH", var);
1130 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1131 if (sscanf(var, "%5lo", &mask) == 1)
1132 umask((mode_t)mask);
1134 for (i = 0; tmpenv[i] != NULL; i++)
1138 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1141 copy_environment(char **source, char ***env, u_int *envsize)
1143 char *var_name, *var_val;
1149 for(i = 0; source[i] != NULL; i++) {
1150 var_name = xstrdup(source[i]);
1151 if ((var_val = strstr(var_name, "=")) == NULL) {
1157 debug3("Copy environment: %s=%s", var_name, var_val);
1158 child_set_env(env, envsize, var_name, var_val);
1165 do_setup_env(Session *s, const char *shell)
1167 struct ssh *ssh = active_state; /* XXX */
1171 struct passwd *pw = s->pw;
1172 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1176 /* Initialize the environment. */
1178 env = xcalloc(envsize, sizeof(char *));
1183 * The Windows environment contains some setting which are
1184 * important for a running system. They must not be dropped.
1189 p = fetch_windows_environment();
1190 copy_environment(p, &env, &envsize);
1191 free_windows_environment(p);
1196 /* Allow any GSSAPI methods that we've used to alter
1197 * the childs environment as they see fit
1199 ssh_gssapi_do_child(&env, &envsize);
1202 if (!options.use_login) {
1203 /* Set basic environment. */
1204 for (i = 0; i < s->num_env; i++)
1205 child_set_env(&env, &envsize, s->env[i].name,
1208 child_set_env(&env, &envsize, "USER", pw->pw_name);
1209 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1211 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1213 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1214 #ifdef HAVE_LOGIN_CAP
1215 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1216 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1218 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1219 #else /* HAVE_LOGIN_CAP */
1220 # ifndef HAVE_CYGWIN
1222 * There's no standard path on Windows. The path contains
1223 * important components pointing to the system directories,
1224 * needed for loading shared libraries. So the path better
1225 * remains intact here.
1227 # ifdef HAVE_ETC_DEFAULT_LOGIN
1228 read_etc_default_login(&env, &envsize, pw->pw_uid);
1229 path = child_get_env(env, "PATH");
1230 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1231 if (path == NULL || *path == '\0') {
1232 child_set_env(&env, &envsize, "PATH",
1233 s->pw->pw_uid == 0 ?
1234 SUPERUSER_PATH : _PATH_STDPATH);
1236 # endif /* HAVE_CYGWIN */
1237 #endif /* HAVE_LOGIN_CAP */
1239 snprintf(buf, sizeof buf, "%.200s/%.50s",
1240 _PATH_MAILDIR, pw->pw_name);
1241 child_set_env(&env, &envsize, "MAIL", buf);
1243 /* Normal systems set SHELL by default. */
1244 child_set_env(&env, &envsize, "SHELL", shell);
1247 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1249 /* Set custom environment options from RSA authentication. */
1250 if (!options.use_login) {
1251 while (custom_environment) {
1252 struct envstring *ce = custom_environment;
1255 for (i = 0; str[i] != '=' && str[i]; i++)
1257 if (str[i] == '=') {
1259 child_set_env(&env, &envsize, str, str + i + 1);
1261 custom_environment = ce->next;
1267 /* SSH_CLIENT deprecated */
1268 snprintf(buf, sizeof buf, "%.50s %d %d",
1269 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1270 ssh_local_port(ssh));
1271 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1273 laddr = get_local_ipaddr(packet_get_connection_in());
1274 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1275 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1276 laddr, ssh_local_port(ssh));
1278 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1281 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1283 child_set_env(&env, &envsize, "TERM", s->term);
1285 child_set_env(&env, &envsize, "DISPLAY", s->display);
1286 if (original_command)
1287 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1291 if (cray_tmpdir[0] != '\0')
1292 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1293 #endif /* _UNICOS */
1296 * Since we clear KRB5CCNAME at startup, if it's set now then it
1297 * must have been set by a native authentication method (eg AIX or
1298 * SIA), so copy it to the child.
1303 if ((cp = getenv("KRB5CCNAME")) != NULL)
1304 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1311 if ((cp = getenv("AUTHSTATE")) != NULL)
1312 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1313 read_environment_file(&env, &envsize, "/etc/environment");
1317 if (s->authctxt->krb5_ccname)
1318 child_set_env(&env, &envsize, "KRB5CCNAME",
1319 s->authctxt->krb5_ccname);
1323 * Pull in any environment variables that may have
1326 if (options.use_pam && !options.use_login) {
1329 p = fetch_pam_child_environment();
1330 copy_environment(p, &env, &envsize);
1331 free_pam_environment(p);
1333 p = fetch_pam_environment();
1334 copy_environment(p, &env, &envsize);
1335 free_pam_environment(p);
1337 #endif /* USE_PAM */
1339 if (auth_sock_name != NULL)
1340 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1343 /* read $HOME/.ssh/environment. */
1344 if (options.permit_user_env && !options.use_login) {
1345 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1346 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1347 read_environment_file(&env, &envsize, buf);
1350 /* dump the environment */
1351 fprintf(stderr, "Environment:\n");
1352 for (i = 0; env[i]; i++)
1353 fprintf(stderr, " %.200s\n", env[i]);
1359 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1360 * first in this order).
1363 do_rc_files(Session *s, const char *shell)
1371 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1373 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1374 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1375 !no_user_rc && options.permit_user_rc &&
1376 stat(_PATH_SSH_USER_RC, &st) >= 0) {
1377 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1378 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1380 fprintf(stderr, "Running %s\n", cmd);
1381 f = popen(cmd, "w");
1384 fprintf(f, "%s %s\n", s->auth_proto,
1388 fprintf(stderr, "Could not run %s\n",
1390 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1392 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1393 _PATH_SSH_SYSTEM_RC);
1394 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1397 fprintf(f, "%s %s\n", s->auth_proto,
1401 fprintf(stderr, "Could not run %s\n",
1402 _PATH_SSH_SYSTEM_RC);
1403 } else if (do_xauth && options.xauth_location != NULL) {
1404 /* Add authority data to .Xauthority if appropriate. */
1407 "Running %.500s remove %.100s\n",
1408 options.xauth_location, s->auth_display);
1410 "%.500s add %.100s %.100s %.100s\n",
1411 options.xauth_location, s->auth_display,
1412 s->auth_proto, s->auth_data);
1414 snprintf(cmd, sizeof cmd, "%s -q -",
1415 options.xauth_location);
1416 f = popen(cmd, "w");
1418 fprintf(f, "remove %s\n",
1420 fprintf(f, "add %s %s %s\n",
1421 s->auth_display, s->auth_proto,
1425 fprintf(stderr, "Could not run %s\n",
1432 do_nologin(struct passwd *pw)
1435 char buf[1024], *def_nl = _PATH_NOLOGIN;
1439 #ifdef HAVE_LOGIN_CAP
1440 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1442 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1444 if (pw->pw_uid == 0)
1448 if (stat(nl, &sb) == -1) {
1450 free(__DECONST(char *, nl)); /* __DECONST() safe */
1454 /* /etc/nologin exists. Print its contents if we can and exit. */
1455 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1456 if ((f = fopen(nl, "r")) != NULL) {
1457 while (fgets(buf, sizeof(buf), f))
1465 * Chroot into a directory after checking it for safety: all path components
1466 * must be root-owned directories with strict permissions.
1469 safely_chroot(const char *path, uid_t uid)
1472 char component[PATH_MAX];
1476 fatal("chroot path does not begin at root");
1477 if (strlen(path) >= sizeof(component))
1478 fatal("chroot path too long");
1481 * Descend the path, checking that each component is a
1482 * root-owned directory with strict permissions.
1484 for (cp = path; cp != NULL;) {
1485 if ((cp = strchr(cp, '/')) == NULL)
1486 strlcpy(component, path, sizeof(component));
1489 memcpy(component, path, cp - path);
1490 component[cp - path] = '\0';
1493 debug3("%s: checking '%s'", __func__, component);
1495 if (stat(component, &st) != 0)
1496 fatal("%s: stat(\"%s\"): %s", __func__,
1497 component, strerror(errno));
1498 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1499 fatal("bad ownership or modes for chroot "
1500 "directory %s\"%s\"",
1501 cp == NULL ? "" : "component ", component);
1502 if (!S_ISDIR(st.st_mode))
1503 fatal("chroot path %s\"%s\" is not a directory",
1504 cp == NULL ? "" : "component ", component);
1508 if (chdir(path) == -1)
1509 fatal("Unable to chdir to chroot path \"%s\": "
1510 "%s", path, strerror(errno));
1511 if (chroot(path) == -1)
1512 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1513 if (chdir("/") == -1)
1514 fatal("%s: chdir(/) after chroot: %s",
1515 __func__, strerror(errno));
1516 verbose("Changed root directory to \"%s\"", path);
1519 /* Set login name, uid, gid, and groups. */
1521 do_setusercontext(struct passwd *pw)
1523 char *chroot_path, *tmp;
1525 platform_setusercontext(pw);
1527 if (platform_privileged_uidswap()) {
1528 #ifdef HAVE_LOGIN_CAP
1529 if (setusercontext(lc, pw, pw->pw_uid,
1530 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1531 perror("unable to set user context");
1535 if (setlogin(pw->pw_name) < 0)
1536 error("setlogin failed: %s", strerror(errno));
1537 if (setgid(pw->pw_gid) < 0) {
1541 /* Initialize the group list. */
1542 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1543 perror("initgroups");
1549 platform_setusercontext_post_groups(pw);
1551 if (!in_chroot && options.chroot_directory != NULL &&
1552 strcasecmp(options.chroot_directory, "none") != 0) {
1553 tmp = tilde_expand_filename(options.chroot_directory,
1555 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1556 "u", pw->pw_name, (char *)NULL);
1557 safely_chroot(chroot_path, pw->pw_uid);
1560 /* Make sure we don't attempt to chroot again */
1561 free(options.chroot_directory);
1562 options.chroot_directory = NULL;
1566 #ifdef HAVE_LOGIN_CAP
1567 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1568 perror("unable to set user context (setuser)");
1572 * FreeBSD's setusercontext() will not apply the user's
1573 * own umask setting unless running with the user's UID.
1575 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK);
1579 * In a chroot environment, the set_id() will always fail;
1580 * typically because of the lack of necessary authentication
1581 * services and runtime such as ./usr/lib/libiaf.so,
1582 * ./usr/lib/libpam.so.1, and ./etc/passwd We skip it in the
1583 * internal sftp chroot case. We'll lose auditing and ACLs but
1584 * permanently_set_uid will take care of the rest.
1586 if (!in_chroot && set_id(pw->pw_name) != 0)
1587 fatal("set_id(%s) Failed", pw->pw_name);
1588 # endif /* USE_LIBIAF */
1589 /* Permanently switch to the desired uid. */
1590 permanently_set_uid(pw);
1592 } else if (options.chroot_directory != NULL &&
1593 strcasecmp(options.chroot_directory, "none") != 0) {
1594 fatal("server lacks privileges to chroot to ChrootDirectory");
1597 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1598 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1602 do_pwchange(Session *s)
1605 fprintf(stderr, "WARNING: Your password has expired.\n");
1606 if (s->ttyfd != -1) {
1608 "You must change your password now and login again!\n");
1612 #ifdef PASSWD_NEEDS_USERNAME
1613 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1616 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1621 "Password change required but no TTY available.\n");
1627 launch_login(struct passwd *pw, const char *hostname)
1629 /* Launch login(1). */
1631 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1632 #ifdef xxxLOGIN_NEEDS_TERM
1633 (s->term ? s->term : "unknown"),
1634 #endif /* LOGIN_NEEDS_TERM */
1635 #ifdef LOGIN_NO_ENDOPT
1636 "-p", "-f", pw->pw_name, (char *)NULL);
1638 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1641 /* Login couldn't be executed, die. */
1648 child_close_fds(void)
1650 extern int auth_sock;
1652 if (auth_sock != -1) {
1657 if (packet_get_connection_in() == packet_get_connection_out())
1658 close(packet_get_connection_in());
1660 close(packet_get_connection_in());
1661 close(packet_get_connection_out());
1664 * Close all descriptors related to channels. They will still remain
1665 * open in the parent.
1667 /* XXX better use close-on-exec? -markus */
1668 channel_close_all();
1671 * Close any extra file descriptors. Note that there may still be
1672 * descriptors left by system functions. They will be closed later.
1677 * Close any extra open file descriptors so that we don't have them
1678 * hanging around in clients. Note that we want to do this after
1679 * initgroups, because at least on Solaris 2.3 it leaves file
1682 closefrom(STDERR_FILENO + 1);
1686 * Performs common processing for the child, such as setting up the
1687 * environment, closing extra file descriptors, setting the user and group
1688 * ids, and executing the command or shell.
1692 do_child(Session *s, const char *command)
1694 struct ssh *ssh = active_state; /* XXX */
1695 extern char **environ;
1697 char *argv[ARGV_MAX];
1698 const char *shell, *shell0, *hostname = NULL;
1699 struct passwd *pw = s->pw;
1702 /* remove hostkey from the child's memory */
1703 destroy_sensitive_data();
1705 /* Force a password change */
1706 if (s->authctxt->force_pwchange) {
1707 do_setusercontext(pw);
1713 /* login(1) is only called if we execute the login shell */
1714 if (options.use_login && command != NULL)
1715 options.use_login = 0;
1718 cray_setup(pw->pw_uid, pw->pw_name, command);
1719 #endif /* _UNICOS */
1722 * Login(1) does this as well, and it needs uid 0 for the "-h"
1723 * switch, so we let login(1) to this for us.
1725 if (!options.use_login) {
1727 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1728 if (!check_quietlogin(s, command))
1730 #else /* HAVE_OSF_SIA */
1731 /* When PAM is enabled we rely on it to do the nologin check */
1732 if (!options.use_pam)
1734 do_setusercontext(pw);
1736 * PAM session modules in do_setusercontext may have
1737 * generated messages, so if this in an interactive
1738 * login then display them too.
1740 if (!check_quietlogin(s, command))
1742 #endif /* HAVE_OSF_SIA */
1746 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1747 debug3("PAM session not opened, exiting");
1754 * Get the shell from the password data. An empty shell field is
1755 * legal, and means /bin/sh.
1757 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1760 * Make sure $SHELL points to the shell from the password file,
1761 * even if shell is overridden from login.conf
1763 env = do_setup_env(s, shell);
1765 #ifdef HAVE_LOGIN_CAP
1766 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1769 /* we have to stash the hostname before we close our socket. */
1770 if (options.use_login)
1771 hostname = session_get_remote_name_or_ip(ssh, utmp_len,
1774 * Close the connection descriptors; note that this is the child, and
1775 * the server will still have the socket open, and it is important
1776 * that we do not shutdown it. Note that the descriptors cannot be
1777 * closed before building the environment, as we call
1778 * ssh_remote_ipaddr there.
1783 * Must take new environment into use so that .ssh/rc,
1784 * /etc/ssh/sshrc and xauth are run in the proper environment.
1788 #if defined(KRB5) && defined(USE_AFS)
1790 * At this point, we check to see if AFS is active and if we have
1791 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1792 * if we can (and need to) extend the ticket into an AFS token. If
1793 * we don't do this, we run into potential problems if the user's
1794 * home directory is in AFS and it's not world-readable.
1797 if (options.kerberos_get_afs_token && k_hasafs() &&
1798 (s->authctxt->krb5_ctx != NULL)) {
1801 debug("Getting AFS token");
1805 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1806 krb5_afslog(s->authctxt->krb5_ctx,
1807 s->authctxt->krb5_fwd_ccache, cell, NULL);
1809 krb5_afslog_home(s->authctxt->krb5_ctx,
1810 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1814 /* Change current directory to the user's home directory. */
1815 if (chdir(pw->pw_dir) < 0) {
1816 /* Suppress missing homedir warning for chroot case */
1817 #ifdef HAVE_LOGIN_CAP
1818 r = login_getcapbool(lc, "requirehome", 0);
1820 if (r || !in_chroot) {
1821 fprintf(stderr, "Could not chdir to home "
1822 "directory %s: %s\n", pw->pw_dir,
1829 closefrom(STDERR_FILENO + 1);
1831 if (!options.use_login)
1832 do_rc_files(s, shell);
1834 /* restore SIGPIPE for child */
1835 signal(SIGPIPE, SIG_DFL);
1837 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1838 printf("This service allows sftp connections only.\n");
1841 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1842 extern int optind, optreset;
1846 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1847 args = xstrdup(command ? command : "sftp-server");
1848 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1849 if (i < ARGV_MAX - 1)
1852 optind = optreset = 1;
1853 __progname = argv[0];
1855 ssh_selinux_change_context("sftpd_t");
1857 exit(sftp_server_main(i, argv, s->pw));
1862 if (options.use_login) {
1863 launch_login(pw, hostname);
1867 /* Get the last component of the shell name. */
1868 if ((shell0 = strrchr(shell, '/')) != NULL)
1874 * If we have no command, execute the shell. In this case, the shell
1875 * name to be passed in argv[0] is preceded by '-' to indicate that
1876 * this is a login shell.
1881 /* Start the shell. Set initial character to '-'. */
1884 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1885 >= sizeof(argv0) - 1) {
1891 /* Execute the shell. */
1894 execve(shell, argv, env);
1896 /* Executing the shell failed. */
1901 * Execute the command using the user's shell. This uses the -c
1902 * option to execute the command.
1904 argv[0] = (char *) shell0;
1906 argv[2] = (char *) command;
1908 execve(shell, argv, env);
1914 session_unused(int id)
1916 debug3("%s: session id %d unused", __func__, id);
1917 if (id >= options.max_sessions ||
1918 id >= sessions_nalloc) {
1919 fatal("%s: insane session id %d (max %d nalloc %d)",
1920 __func__, id, options.max_sessions, sessions_nalloc);
1922 memset(&sessions[id], 0, sizeof(*sessions));
1923 sessions[id].self = id;
1924 sessions[id].used = 0;
1925 sessions[id].chanid = -1;
1926 sessions[id].ptyfd = -1;
1927 sessions[id].ttyfd = -1;
1928 sessions[id].ptymaster = -1;
1929 sessions[id].x11_chanids = NULL;
1930 sessions[id].next_unused = sessions_first_unused;
1931 sessions_first_unused = id;
1939 if (sessions_first_unused == -1) {
1940 if (sessions_nalloc >= options.max_sessions)
1942 debug2("%s: allocate (allocated %d max %d)",
1943 __func__, sessions_nalloc, options.max_sessions);
1944 tmp = xreallocarray(sessions, sessions_nalloc + 1,
1947 error("%s: cannot allocate %d sessions",
1948 __func__, sessions_nalloc + 1);
1952 session_unused(sessions_nalloc++);
1955 if (sessions_first_unused >= sessions_nalloc ||
1956 sessions_first_unused < 0) {
1957 fatal("%s: insane first_unused %d max %d nalloc %d",
1958 __func__, sessions_first_unused, options.max_sessions,
1962 s = &sessions[sessions_first_unused];
1964 fatal("%s: session %d already used",
1965 __func__, sessions_first_unused);
1967 sessions_first_unused = s->next_unused;
1969 s->next_unused = -1;
1970 debug("session_new: session %d", s->self);
1979 for (i = 0; i < sessions_nalloc; i++) {
1980 Session *s = &sessions[i];
1982 debug("dump: used %d next_unused %d session %d %p "
1983 "channel %d pid %ld",
1994 session_open(Authctxt *authctxt, int chanid)
1996 Session *s = session_new();
1997 debug("session_open: channel %d", chanid);
1999 error("no more sessions");
2002 s->authctxt = authctxt;
2003 s->pw = authctxt->pw;
2004 if (s->pw == NULL || !authctxt->valid)
2005 fatal("no user for session %d", s->self);
2006 debug("session_open: session %d: link with channel %d", s->self, chanid);
2012 session_by_tty(char *tty)
2015 for (i = 0; i < sessions_nalloc; i++) {
2016 Session *s = &sessions[i];
2017 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2018 debug("session_by_tty: session %d tty %s", i, tty);
2022 debug("session_by_tty: unknown tty %.100s", tty);
2028 session_by_channel(int id)
2031 for (i = 0; i < sessions_nalloc; i++) {
2032 Session *s = &sessions[i];
2033 if (s->used && s->chanid == id) {
2034 debug("session_by_channel: session %d channel %d",
2039 debug("session_by_channel: unknown channel %d", id);
2045 session_by_x11_channel(int id)
2049 for (i = 0; i < sessions_nalloc; i++) {
2050 Session *s = &sessions[i];
2052 if (s->x11_chanids == NULL || !s->used)
2054 for (j = 0; s->x11_chanids[j] != -1; j++) {
2055 if (s->x11_chanids[j] == id) {
2056 debug("session_by_x11_channel: session %d "
2057 "channel %d", s->self, id);
2062 debug("session_by_x11_channel: unknown channel %d", id);
2068 session_by_pid(pid_t pid)
2071 debug("session_by_pid: pid %ld", (long)pid);
2072 for (i = 0; i < sessions_nalloc; i++) {
2073 Session *s = &sessions[i];
2074 if (s->used && s->pid == pid)
2077 error("session_by_pid: unknown pid %ld", (long)pid);
2083 session_window_change_req(Session *s)
2085 s->col = packet_get_int();
2086 s->row = packet_get_int();
2087 s->xpixel = packet_get_int();
2088 s->ypixel = packet_get_int();
2090 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2095 session_pty_req(Session *s)
2100 if (no_pty_flag || !options.permit_tty) {
2101 debug("Allocating a pty not permitted for this authentication.");
2104 if (s->ttyfd != -1) {
2105 packet_disconnect("Protocol error: you already have a pty.");
2109 s->term = packet_get_string(&len);
2112 s->col = packet_get_int();
2113 s->row = packet_get_int();
2115 s->row = packet_get_int();
2116 s->col = packet_get_int();
2118 s->xpixel = packet_get_int();
2119 s->ypixel = packet_get_int();
2121 if (strcmp(s->term, "") == 0) {
2126 /* Allocate a pty and open it. */
2127 debug("Allocating pty.");
2128 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2134 error("session_pty_req: session %d alloc failed", s->self);
2137 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2139 /* for SSH1 the tty modes length is not given */
2141 n_bytes = packet_remaining();
2142 tty_parse_modes(s->ttyfd, &n_bytes);
2145 pty_setowner(s->pw, s->tty);
2147 /* Set window size from the packet. */
2148 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2151 session_proctitle(s);
2156 session_subsystem_req(Session *s)
2164 s->subsys = packet_get_string(&len);
2166 debug2("subsystem request for %.100s by user %s", s->subsys,
2169 for (i = 0; i < options.num_subsystems; i++) {
2170 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
2171 prog = options.subsystem_command[i];
2172 cmd = options.subsystem_args[i];
2173 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2174 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2175 debug("subsystem: %s", prog);
2177 if (stat(prog, &st) < 0)
2178 debug("subsystem: cannot stat %s: %s",
2179 prog, strerror(errno));
2180 s->is_subsystem = SUBSYSTEM_EXT;
2181 debug("subsystem: exec() %s", cmd);
2183 success = do_exec(s, cmd) == 0;
2189 logit("subsystem request for %.100s by user %s failed, "
2190 "subsystem not found", s->subsys, s->pw->pw_name);
2196 session_x11_req(Session *s)
2200 if (s->auth_proto != NULL || s->auth_data != NULL) {
2201 error("session_x11_req: session %d: "
2202 "x11 forwarding already active", s->self);
2205 s->single_connection = packet_get_char();
2206 s->auth_proto = packet_get_string(NULL);
2207 s->auth_data = packet_get_string(NULL);
2208 s->screen = packet_get_int();
2211 if (xauth_valid_string(s->auth_proto) &&
2212 xauth_valid_string(s->auth_data))
2213 success = session_setup_x11fwd(s);
2216 error("Invalid X11 forwarding data");
2219 free(s->auth_proto);
2221 s->auth_proto = NULL;
2222 s->auth_data = NULL;
2228 session_shell_req(Session *s)
2231 return do_exec(s, NULL) == 0;
2235 session_exec_req(Session *s)
2239 char *command = packet_get_string(&len);
2241 success = do_exec(s, command) == 0;
2247 session_break_req(Session *s)
2250 packet_get_int(); /* ignored */
2253 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2259 session_env_req(Session *s)
2262 u_int name_len, val_len, i;
2264 name = packet_get_cstring(&name_len);
2265 val = packet_get_cstring(&val_len);
2268 /* Don't set too many environment variables */
2269 if (s->num_env > 128) {
2270 debug2("Ignoring env request %s: too many env vars", name);
2274 for (i = 0; i < options.num_accept_env; i++) {
2275 if (match_pattern(name, options.accept_env[i])) {
2276 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2277 s->env = xreallocarray(s->env, s->num_env + 1,
2279 s->env[s->num_env].name = name;
2280 s->env[s->num_env].val = val;
2285 debug2("Ignoring env request %s: disallowed name", name);
2294 session_auth_agent_req(Session *s)
2296 static int called = 0;
2298 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2299 debug("session_auth_agent_req: no_agent_forwarding_flag");
2306 return auth_input_request_forwarding(s->pw);
2311 session_input_channel_req(Channel *c, const char *rtype)
2316 if ((s = session_by_channel(c->self)) == NULL) {
2317 logit("session_input_channel_req: no session %d req %.100s",
2321 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2324 * a session is in LARVAL state until a shell, a command
2325 * or a subsystem is executed
2327 if (c->type == SSH_CHANNEL_LARVAL) {
2328 if (strcmp(rtype, "shell") == 0) {
2329 success = session_shell_req(s);
2330 } else if (strcmp(rtype, "exec") == 0) {
2331 success = session_exec_req(s);
2332 } else if (strcmp(rtype, "pty-req") == 0) {
2333 success = session_pty_req(s);
2334 } else if (strcmp(rtype, "x11-req") == 0) {
2335 success = session_x11_req(s);
2336 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2337 success = session_auth_agent_req(s);
2338 } else if (strcmp(rtype, "subsystem") == 0) {
2339 success = session_subsystem_req(s);
2340 } else if (strcmp(rtype, "env") == 0) {
2341 success = session_env_req(s);
2344 if (strcmp(rtype, "window-change") == 0) {
2345 success = session_window_change_req(s);
2346 } else if (strcmp(rtype, "break") == 0) {
2347 success = session_break_req(s);
2354 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2358 fatal("session_set_fds: called for proto != 2.0");
2360 * now that have a child and a pipe to the child,
2361 * we can activate our channel and register the fd's
2363 if (s->chanid == -1)
2364 fatal("no channel for session %d", s->self);
2365 channel_set_fds(s->chanid,
2367 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2368 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2372 * Function to perform pty cleanup. Also called if we get aborted abnormally
2373 * (e.g., due to a dropped connection).
2376 session_pty_cleanup2(Session *s)
2379 error("session_pty_cleanup: no session");
2385 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2387 /* Record that the user has logged out. */
2389 record_logout(s->pid, s->tty, s->pw->pw_name);
2391 /* Release the pseudo-tty. */
2393 pty_release(s->tty);
2396 * Close the server side of the socket pairs. We must do this after
2397 * the pty cleanup, so that another process doesn't get this pty
2398 * while we're still cleaning up.
2400 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2401 error("close(s->ptymaster/%d): %s",
2402 s->ptymaster, strerror(errno));
2404 /* unlink pty from session */
2409 session_pty_cleanup(Session *s)
2411 PRIVSEP(session_pty_cleanup2(s));
2417 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2432 return "SIG@openssh.com";
2436 session_close_x11(int id)
2440 if ((c = channel_by_id(id)) == NULL) {
2441 debug("session_close_x11: x11 channel %d missing", id);
2443 /* Detach X11 listener */
2444 debug("session_close_x11: detach x11 channel %d", id);
2445 channel_cancel_cleanup(id);
2446 if (c->ostate != CHAN_OUTPUT_CLOSED)
2452 session_close_single_x11(int id, void *arg)
2457 debug3("session_close_single_x11: channel %d", id);
2458 channel_cancel_cleanup(id);
2459 if ((s = session_by_x11_channel(id)) == NULL)
2460 fatal("session_close_single_x11: no x11 channel %d", id);
2461 for (i = 0; s->x11_chanids[i] != -1; i++) {
2462 debug("session_close_single_x11: session %d: "
2463 "closing channel %d", s->self, s->x11_chanids[i]);
2465 * The channel "id" is already closing, but make sure we
2466 * close all of its siblings.
2468 if (s->x11_chanids[i] != id)
2469 session_close_x11(s->x11_chanids[i]);
2471 free(s->x11_chanids);
2472 s->x11_chanids = NULL;
2475 free(s->auth_proto);
2476 s->auth_proto = NULL;
2478 s->auth_data = NULL;
2479 free(s->auth_display);
2480 s->auth_display = NULL;
2484 session_exit_message(Session *s, int status)
2488 if ((c = channel_lookup(s->chanid)) == NULL)
2489 fatal("session_exit_message: session %d: no channel %d",
2490 s->self, s->chanid);
2491 debug("session_exit_message: session %d channel %d pid %ld",
2492 s->self, s->chanid, (long)s->pid);
2494 if (WIFEXITED(status)) {
2495 channel_request_start(s->chanid, "exit-status", 0);
2496 packet_put_int(WEXITSTATUS(status));
2498 } else if (WIFSIGNALED(status)) {
2499 channel_request_start(s->chanid, "exit-signal", 0);
2500 packet_put_cstring(sig2name(WTERMSIG(status)));
2502 packet_put_char(WCOREDUMP(status)? 1 : 0);
2503 #else /* WCOREDUMP */
2505 #endif /* WCOREDUMP */
2506 packet_put_cstring("");
2507 packet_put_cstring("");
2510 /* Some weird exit cause. Just exit. */
2511 packet_disconnect("wait returned status %04x.", status);
2514 /* disconnect channel */
2515 debug("session_exit_message: release channel %d", s->chanid);
2518 * Adjust cleanup callback attachment to send close messages when
2519 * the channel gets EOF. The session will be then be closed
2520 * by session_close_by_channel when the childs close their fds.
2522 channel_register_cleanup(c->self, session_close_by_channel, 1);
2525 * emulate a write failure with 'chan_write_failed', nobody will be
2526 * interested in data we write.
2527 * Note that we must not call 'chan_read_failed', since there could
2528 * be some more data waiting in the pipe.
2530 if (c->ostate != CHAN_OUTPUT_CLOSED)
2531 chan_write_failed(c);
2535 session_close(Session *s)
2537 struct ssh *ssh = active_state; /* XXX */
2540 verbose("Close session: user %s from %.200s port %d id %d",
2542 ssh_remote_ipaddr(ssh),
2543 ssh_remote_port(ssh),
2547 session_pty_cleanup(s);
2550 free(s->x11_chanids);
2551 free(s->auth_display);
2553 free(s->auth_proto);
2555 if (s->env != NULL) {
2556 for (i = 0; i < s->num_env; i++) {
2557 free(s->env[i].name);
2558 free(s->env[i].val);
2562 session_proctitle(s);
2563 session_unused(s->self);
2567 session_close_by_pid(pid_t pid, int status)
2569 Session *s = session_by_pid(pid);
2571 debug("session_close_by_pid: no session for pid %ld",
2575 if (s->chanid != -1)
2576 session_exit_message(s, status);
2578 session_pty_cleanup(s);
2583 * this is called when a channel dies before
2584 * the session 'child' itself dies
2587 session_close_by_channel(int id, void *arg)
2589 Session *s = session_by_channel(id);
2593 debug("session_close_by_channel: no session for id %d", id);
2596 debug("session_close_by_channel: channel %d child %ld",
2599 debug("session_close_by_channel: channel %d: has child", id);
2601 * delay detach of session, but release pty, since
2602 * the fd's to the child are already closed
2605 session_pty_cleanup(s);
2608 /* detach by removing callback */
2609 channel_cancel_cleanup(s->chanid);
2611 /* Close any X11 listeners associated with this session */
2612 if (s->x11_chanids != NULL) {
2613 for (i = 0; s->x11_chanids[i] != -1; i++) {
2614 session_close_x11(s->x11_chanids[i]);
2615 s->x11_chanids[i] = -1;
2624 session_destroy_all(void (*closefunc)(Session *))
2627 for (i = 0; i < sessions_nalloc; i++) {
2628 Session *s = &sessions[i];
2630 if (closefunc != NULL)
2639 session_tty_list(void)
2641 static char buf[1024];
2646 for (i = 0; i < sessions_nalloc; i++) {
2647 Session *s = &sessions[i];
2648 if (s->used && s->ttyfd != -1) {
2650 if (strncmp(s->tty, "/dev/", 5) != 0) {
2651 cp = strrchr(s->tty, '/');
2652 cp = (cp == NULL) ? s->tty : cp + 1;
2657 strlcat(buf, ",", sizeof buf);
2658 strlcat(buf, cp, sizeof buf);
2662 strlcpy(buf, "notty", sizeof buf);
2667 session_proctitle(Session *s)
2670 error("no user for session %d", s->self);
2672 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2676 session_setup_x11fwd(Session *s)
2679 char display[512], auth_display[512];
2680 char hostname[NI_MAXHOST];
2683 if (no_x11_forwarding_flag) {
2684 packet_send_debug("X11 forwarding disabled in user configuration file.");
2687 if (!options.x11_forwarding) {
2688 debug("X11 forwarding disabled in server configuration file.");
2691 if (options.xauth_location == NULL ||
2692 (stat(options.xauth_location, &st) == -1)) {
2693 packet_send_debug("No xauth program; cannot forward with spoofing.");
2696 if (options.use_login) {
2697 packet_send_debug("X11 forwarding disabled; "
2698 "not compatible with UseLogin=yes.");
2701 if (s->display != NULL) {
2702 debug("X11 display already set.");
2705 if (x11_create_display_inet(options.x11_display_offset,
2706 options.x11_use_localhost, s->single_connection,
2707 &s->display_number, &s->x11_chanids) == -1) {
2708 debug("x11_create_display_inet failed.");
2711 for (i = 0; s->x11_chanids[i] != -1; i++) {
2712 channel_register_cleanup(s->x11_chanids[i],
2713 session_close_single_x11, 0);
2716 /* Set up a suitable value for the DISPLAY variable. */
2717 if (gethostname(hostname, sizeof(hostname)) < 0)
2718 fatal("gethostname: %.100s", strerror(errno));
2720 * auth_display must be used as the displayname when the
2721 * authorization entry is added with xauth(1). This will be
2722 * different than the DISPLAY string for localhost displays.
2724 if (options.x11_use_localhost) {
2725 snprintf(display, sizeof display, "localhost:%u.%u",
2726 s->display_number, s->screen);
2727 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2728 s->display_number, s->screen);
2729 s->display = xstrdup(display);
2730 s->auth_display = xstrdup(auth_display);
2732 #ifdef IPADDR_IN_DISPLAY
2734 struct in_addr my_addr;
2736 he = gethostbyname(hostname);
2738 error("Can't get IP address for X11 DISPLAY.");
2739 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2742 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2743 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2744 s->display_number, s->screen);
2746 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2747 s->display_number, s->screen);
2749 s->display = xstrdup(display);
2750 s->auth_display = xstrdup(display);
2757 do_authenticated2(Authctxt *authctxt)
2759 server_loop2(authctxt);
2763 do_cleanup(Authctxt *authctxt)
2765 static int called = 0;
2767 debug("do_cleanup");
2769 /* no cleanup if we're in the child for login shell */
2773 /* avoid double cleanup */
2778 if (authctxt == NULL)
2782 if (options.use_pam) {
2784 sshpam_thread_cleanup();
2788 if (!authctxt->authenticated)
2792 if (options.kerberos_ticket_cleanup &&
2794 krb5_cleanup_proc(authctxt);
2798 if (compat20 && options.gss_cleanup_creds)
2799 ssh_gssapi_cleanup_creds();
2802 /* remove agent socket */
2803 auth_sock_cleanup_proc(authctxt->pw);
2806 * Cleanup ptys/utmp only if privsep is disabled,
2807 * or if running in monitor.
2809 if (!use_privsep || mm_is_monitor())
2810 session_destroy_all(session_pty_cleanup2);
2813 /* Return a name for the remote host that fits inside utmp_size */
2816 session_get_remote_name_or_ip(struct ssh *ssh, u_int utmp_size, int use_dns)
2818 const char *remote = "";
2821 remote = auth_get_canonical_hostname(ssh, use_dns);
2822 if (utmp_size == 0 || strlen(remote) > utmp_size)
2823 remote = ssh_remote_ipaddr(ssh);