1 /* $OpenBSD: session.c,v 1.260 2012/03/15 03:10:27 guenther Exp $ */
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
13 * SSH2 support by Markus Friedl.
14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution.
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 #include <sys/types.h>
41 #include <sys/param.h>
42 #ifdef HAVE_SYS_STAT_H
43 # include <sys/stat.h>
45 #include <sys/socket.h>
49 #include <arpa/inet.h>
65 #include "openbsd-compat/sys-queue.h"
84 #include "auth-options.h"
85 #include "pathnames.h"
89 #include "serverloop.h"
94 #include "monitor_wrap.h"
97 #if defined(KRB5) && defined(USE_AFS)
102 #include <selinux/selinux.h>
105 #define IS_INTERNAL_SFTP(c) \
106 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
107 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
108 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
109 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
113 Session *session_new(void);
114 void session_set_fds(Session *, int, int, int, int, int);
115 void session_pty_cleanup(Session *);
116 void session_proctitle(Session *);
117 int session_setup_x11fwd(Session *);
118 int do_exec_pty(Session *, const char *);
119 int do_exec_no_pty(Session *, const char *);
120 int do_exec(Session *, const char *);
121 void do_login(Session *, const char *);
122 #ifdef LOGIN_NEEDS_UTMPX
123 static void do_pre_login(Session *s);
125 void do_child(Session *, const char *);
127 int check_quietlogin(Session *, const char *);
129 static void do_authenticated1(Authctxt *);
130 static void do_authenticated2(Authctxt *);
132 static int session_pty_req(Session *);
135 extern ServerOptions options;
136 extern char *__progname;
137 extern int log_stderr;
138 extern int debug_flag;
139 extern u_int utmp_len;
140 extern int startup_pipe;
141 extern void destroy_sensitive_data(void);
142 extern Buffer loginmsg;
144 /* original command from peer. */
145 const char *original_command = NULL;
148 static int sessions_first_unused = -1;
149 static int sessions_nalloc = 0;
150 static Session *sessions = NULL;
152 #define SUBSYSTEM_NONE 0
153 #define SUBSYSTEM_EXT 1
154 #define SUBSYSTEM_INT_SFTP 2
155 #define SUBSYSTEM_INT_SFTP_ERROR 3
157 #ifdef HAVE_LOGIN_CAP
161 static int is_child = 0;
163 /* Name and directory of socket for authentication agent forwarding. */
164 static char *auth_sock_name = NULL;
165 static char *auth_sock_dir = NULL;
167 /* removes the agent forwarding socket */
170 auth_sock_cleanup_proc(struct passwd *pw)
172 if (auth_sock_name != NULL) {
173 temporarily_use_uid(pw);
174 unlink(auth_sock_name);
175 rmdir(auth_sock_dir);
176 auth_sock_name = NULL;
182 auth_input_request_forwarding(struct passwd * pw)
186 struct sockaddr_un sunaddr;
188 if (auth_sock_name != NULL) {
189 error("authentication forwarding requested twice.");
193 /* Temporarily drop privileged uid for mkdir/bind. */
194 temporarily_use_uid(pw);
196 /* Allocate a buffer for the socket name, and format the name. */
197 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
199 /* Create private directory for socket */
200 if (mkdtemp(auth_sock_dir) == NULL) {
201 packet_send_debug("Agent forwarding disabled: "
202 "mkdtemp() failed: %.100s", strerror(errno));
204 xfree(auth_sock_dir);
205 auth_sock_dir = NULL;
209 xasprintf(&auth_sock_name, "%s/agent.%ld",
210 auth_sock_dir, (long) getpid());
212 /* Create the socket. */
213 sock = socket(AF_UNIX, SOCK_STREAM, 0);
215 error("socket: %.100s", strerror(errno));
220 /* Bind it to the name. */
221 memset(&sunaddr, 0, sizeof(sunaddr));
222 sunaddr.sun_family = AF_UNIX;
223 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
225 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
226 error("bind: %.100s", strerror(errno));
231 /* Restore the privileged uid. */
234 /* Start listening on the socket. */
235 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
236 error("listen: %.100s", strerror(errno));
241 * Allocate a channel for the authentication agent socket.
242 * Ignore HPN on that one given no improvement expected.
244 nc = channel_new("auth socket",
245 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
246 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
247 0, "auth socket", 1);
248 nc->path = xstrdup(auth_sock_name);
252 if (auth_sock_name != NULL)
253 xfree(auth_sock_name);
254 if (auth_sock_dir != NULL) {
255 rmdir(auth_sock_dir);
256 xfree(auth_sock_dir);
260 auth_sock_name = NULL;
261 auth_sock_dir = NULL;
266 display_loginmsg(void)
268 if (buffer_len(&loginmsg) > 0) {
269 buffer_append(&loginmsg, "\0", 1);
270 printf("%s", (char *)buffer_ptr(&loginmsg));
271 buffer_clear(&loginmsg);
276 do_authenticated(Authctxt *authctxt)
278 setproctitle("%s", authctxt->pw->pw_name);
280 /* setup the channel layer */
281 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
282 channel_permit_all_opens();
287 do_authenticated2(authctxt);
289 do_authenticated1(authctxt);
291 do_cleanup(authctxt);
295 * Prepares for an interactive session. This is called after the user has
296 * been successfully authenticated. During this message exchange, pseudo
297 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
298 * are requested, etc.
301 do_authenticated1(Authctxt *authctxt)
305 int success, type, screen_flag;
306 int enable_compression_after_reply = 0;
307 u_int proto_len, data_len, dlen, compression_level = 0;
311 error("no more sessions");
314 s->authctxt = authctxt;
315 s->pw = authctxt->pw;
318 * We stay in this loop until the client requests to execute a shell
324 /* Get a packet from the client. */
325 type = packet_read();
327 /* Process the packet. */
329 case SSH_CMSG_REQUEST_COMPRESSION:
330 compression_level = packet_get_int();
332 if (compression_level < 1 || compression_level > 9) {
333 packet_send_debug("Received invalid compression level %d.",
337 if (options.compression == COMP_NONE) {
338 debug2("compression disabled");
341 /* Enable compression after we have responded with SUCCESS. */
342 enable_compression_after_reply = 1;
346 case SSH_CMSG_REQUEST_PTY:
347 success = session_pty_req(s);
350 case SSH_CMSG_X11_REQUEST_FORWARDING:
351 s->auth_proto = packet_get_string(&proto_len);
352 s->auth_data = packet_get_string(&data_len);
354 screen_flag = packet_get_protocol_flags() &
355 SSH_PROTOFLAG_SCREEN_NUMBER;
356 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
358 if (packet_remaining() == 4) {
360 debug2("Buggy client: "
361 "X11 screen flag missing");
362 s->screen = packet_get_int();
367 success = session_setup_x11fwd(s);
369 xfree(s->auth_proto);
371 s->auth_proto = NULL;
376 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
377 if (!options.allow_agent_forwarding ||
378 no_agent_forwarding_flag || compat13) {
379 debug("Authentication agent forwarding not permitted for this authentication.");
382 debug("Received authentication agent forwarding request.");
383 success = auth_input_request_forwarding(s->pw);
386 case SSH_CMSG_PORT_FORWARD_REQUEST:
387 if (no_port_forwarding_flag) {
388 debug("Port forwarding not permitted for this authentication.");
391 if (!options.allow_tcp_forwarding) {
392 debug("Port forwarding not permitted.");
395 debug("Received TCP/IP port forwarding request.");
396 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
397 options.gateway_ports) < 0) {
398 debug("Port forwarding failed.");
404 case SSH_CMSG_MAX_PACKET_SIZE:
405 if (packet_set_maxsize(packet_get_int()) > 0)
409 case SSH_CMSG_EXEC_SHELL:
410 case SSH_CMSG_EXEC_CMD:
411 if (type == SSH_CMSG_EXEC_CMD) {
412 command = packet_get_string(&dlen);
413 debug("Exec command '%.500s'", command);
414 if (do_exec(s, command) != 0)
416 "command execution failed");
419 if (do_exec(s, NULL) != 0)
421 "shell execution failed");
429 * Any unknown messages in this phase are ignored,
430 * and a failure message is returned.
432 logit("Unknown packet type received after authentication: %d", type);
434 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
438 /* Enable compression now that we have replied if appropriate. */
439 if (enable_compression_after_reply) {
440 enable_compression_after_reply = 0;
441 packet_start_compression(compression_level);
448 * This is called to fork and execute a command when we have no tty. This
449 * will call do_child from the child, and server_loop from the parent after
450 * setting up file descriptors and such.
453 do_exec_no_pty(Session *s, const char *command)
458 int pin[2], pout[2], perr[2];
461 fatal("do_exec_no_pty: no session");
463 /* Allocate pipes for communicating with the program. */
465 error("%s: pipe in: %.100s", __func__, strerror(errno));
468 if (pipe(pout) < 0) {
469 error("%s: pipe out: %.100s", __func__, strerror(errno));
474 if (pipe(perr) < 0) {
475 error("%s: pipe err: %.100s", __func__,
484 int inout[2], err[2];
487 fatal("do_exec_no_pty: no session");
489 /* Uses socket pairs to communicate with the program. */
490 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
491 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
494 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
495 error("%s: socketpair #2: %.100s", __func__,
503 session_proctitle(s);
505 /* Fork the child. */
506 switch ((pid = fork())) {
508 error("%s: fork: %.100s", __func__, strerror(errno));
526 /* Child. Reinitialize the log since the pid has changed. */
527 log_init(__progname, options.log_level,
528 options.log_facility, log_stderr);
531 * Create a new session and process group since the 4.4BSD
532 * setlogin() affects the entire process group.
535 error("setsid failed: %.100s", strerror(errno));
539 * Redirect stdin. We close the parent side of the socket
540 * pair, and make the child side the standard input.
543 if (dup2(pin[0], 0) < 0)
544 perror("dup2 stdin");
547 /* Redirect stdout. */
549 if (dup2(pout[1], 1) < 0)
550 perror("dup2 stdout");
553 /* Redirect stderr. */
555 if (dup2(perr[1], 2) < 0)
556 perror("dup2 stderr");
560 * Redirect stdin, stdout, and stderr. Stdin and stdout will
561 * use the same socket, as some programs (particularly rdist)
562 * seem to depend on it.
566 if (dup2(inout[0], 0) < 0) /* stdin */
567 perror("dup2 stdin");
568 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
569 perror("dup2 stdout");
571 if (dup2(err[0], 2) < 0) /* stderr */
572 perror("dup2 stderr");
578 cray_init_job(s->pw); /* set up cray jid and tmpdir */
581 /* Do processing for the child (exec command etc). */
582 do_child(s, command);
589 signal(WJSIGNAL, cray_job_termination_handler);
592 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
596 /* Set interactive/non-interactive mode. */
597 packet_set_interactive(s->display != NULL,
598 options.ip_qos_interactive, options.ip_qos_bulk);
601 * Clear loginmsg, since it's the child's responsibility to display
602 * it to the user, otherwise multiple sessions may accumulate
603 * multiple copies of the login messages.
605 buffer_clear(&loginmsg);
608 /* We are the parent. Close the child sides of the pipes. */
614 session_set_fds(s, pin[1], pout[0], perr[0],
617 /* Enter the interactive session. */
618 server_loop(pid, pin[1], pout[0], perr[0]);
619 /* server_loop has closed pin[1], pout[0], and perr[0]. */
622 /* We are the parent. Close the child sides of the socket pairs. */
627 * Enter the interactive session. Note: server_loop must be able to
628 * handle the case that fdin and fdout are the same.
631 session_set_fds(s, inout[1], inout[1], err[1],
634 server_loop(pid, inout[1], inout[1], err[1]);
635 /* server_loop has closed inout[1] and err[1]. */
642 * This is called to fork and execute a command when we have a tty. This
643 * will call do_child from the child, and server_loop from the parent after
644 * setting up file descriptors, controlling tty, updating wtmp, utmp,
645 * lastlog, and other such operations.
648 do_exec_pty(Session *s, const char *command)
650 int fdout, ptyfd, ttyfd, ptymaster;
654 fatal("do_exec_pty: no session");
659 * Create another descriptor of the pty master side for use as the
660 * standard input. We could use the original descriptor, but this
661 * simplifies code in server_loop. The descriptor is bidirectional.
662 * Do this before forking (and cleanup in the child) so as to
663 * detect and gracefully fail out-of-fd conditions.
665 if ((fdout = dup(ptyfd)) < 0) {
666 error("%s: dup #1: %s", __func__, strerror(errno));
671 /* we keep a reference to the pty master */
672 if ((ptymaster = dup(ptyfd)) < 0) {
673 error("%s: dup #2: %s", __func__, strerror(errno));
680 /* Fork the child. */
681 switch ((pid = fork())) {
683 error("%s: fork: %.100s", __func__, strerror(errno));
695 /* Child. Reinitialize the log because the pid has changed. */
696 log_init(__progname, options.log_level,
697 options.log_facility, log_stderr);
698 /* Close the master side of the pseudo tty. */
701 /* Make the pseudo tty our controlling tty. */
702 pty_make_controlling_tty(&ttyfd, s->tty);
704 /* Redirect stdin/stdout/stderr from the pseudo tty. */
705 if (dup2(ttyfd, 0) < 0)
706 error("dup2 stdin: %s", strerror(errno));
707 if (dup2(ttyfd, 1) < 0)
708 error("dup2 stdout: %s", strerror(errno));
709 if (dup2(ttyfd, 2) < 0)
710 error("dup2 stderr: %s", strerror(errno));
712 /* Close the extra descriptor for the pseudo tty. */
715 /* record login, etc. similar to login(1) */
717 if (!(options.use_login && command == NULL)) {
719 cray_init_job(s->pw); /* set up cray jid and tmpdir */
721 do_login(s, command);
723 # ifdef LOGIN_NEEDS_UTMPX
729 * Do common processing for the child, such as execing
732 do_child(s, command);
739 signal(WJSIGNAL, cray_job_termination_handler);
742 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
747 /* Parent. Close the slave side of the pseudo tty. */
750 /* Enter interactive session. */
751 s->ptymaster = ptymaster;
752 packet_set_interactive(1,
753 options.ip_qos_interactive, options.ip_qos_bulk);
755 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
757 server_loop(pid, ptyfd, fdout, -1);
758 /* server_loop _has_ closed ptyfd and fdout. */
763 #ifdef LOGIN_NEEDS_UTMPX
765 do_pre_login(Session *s)
768 struct sockaddr_storage from;
769 pid_t pid = getpid();
772 * Get IP address of client. If the connection is not a socket, let
773 * the address be 0.0.0.0.
775 memset(&from, 0, sizeof(from));
776 fromlen = sizeof(from);
777 if (packet_connection_is_on_socket()) {
778 if (getpeername(packet_get_connection_in(),
779 (struct sockaddr *)&from, &fromlen) < 0) {
780 debug("getpeername: %.100s", strerror(errno));
785 record_utmp_only(pid, s->tty, s->pw->pw_name,
786 get_remote_name_or_ip(utmp_len, options.use_dns),
787 (struct sockaddr *)&from, fromlen);
792 * This is called to fork and execute a command. If another command is
793 * to be forced, execute that instead.
796 do_exec(Session *s, const char *command)
800 if (options.adm_forced_command) {
801 original_command = command;
802 command = options.adm_forced_command;
803 if (IS_INTERNAL_SFTP(command)) {
804 s->is_subsystem = s->is_subsystem ?
805 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
806 } else if (s->is_subsystem)
807 s->is_subsystem = SUBSYSTEM_EXT;
808 debug("Forced command (config) '%.900s'", command);
809 } else if (forced_command) {
810 original_command = command;
811 command = forced_command;
812 if (IS_INTERNAL_SFTP(command)) {
813 s->is_subsystem = s->is_subsystem ?
814 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
815 } else if (s->is_subsystem)
816 s->is_subsystem = SUBSYSTEM_EXT;
817 debug("Forced command (key option) '%.900s'", command);
820 #ifdef SSH_AUDIT_EVENTS
822 PRIVSEP(audit_run_command(command));
823 else if (s->ttyfd == -1) {
824 char *shell = s->pw->pw_shell;
826 if (shell[0] == '\0') /* empty shell means /bin/sh */
828 PRIVSEP(audit_run_command(shell));
832 ret = do_exec_pty(s, command);
834 ret = do_exec_no_pty(s, command);
836 original_command = NULL;
839 * Clear loginmsg: it's the child's responsibility to display
840 * it to the user, otherwise multiple sessions may accumulate
841 * multiple copies of the login messages.
843 buffer_clear(&loginmsg);
848 /* administrative, login(1)-like work */
850 do_login(Session *s, const char *command)
853 struct sockaddr_storage from;
854 struct passwd * pw = s->pw;
855 pid_t pid = getpid();
858 * Get IP address of client. If the connection is not a socket, let
859 * the address be 0.0.0.0.
861 memset(&from, 0, sizeof(from));
862 fromlen = sizeof(from);
863 if (packet_connection_is_on_socket()) {
864 if (getpeername(packet_get_connection_in(),
865 (struct sockaddr *)&from, &fromlen) < 0) {
866 debug("getpeername: %.100s", strerror(errno));
871 /* Record that there was a login on that tty from the remote host. */
873 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
874 get_remote_name_or_ip(utmp_len,
876 (struct sockaddr *)&from, fromlen);
880 * If password change is needed, do it now.
881 * This needs to occur before the ~/.hushlogin check.
883 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
886 s->authctxt->force_pwchange = 0;
887 /* XXX - signal [net] parent to enable forwardings */
891 if (check_quietlogin(s, command))
900 * Display the message of the day.
908 if (options.print_motd) {
909 #ifdef HAVE_LOGIN_CAP
910 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
913 f = fopen("/etc/motd", "r");
916 while (fgets(buf, sizeof(buf), f))
925 * Check for quiet login, either .hushlogin or command given.
928 check_quietlogin(Session *s, const char *command)
931 struct passwd *pw = s->pw;
934 /* Return 1 if .hushlogin exists or a command given. */
937 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
938 #ifdef HAVE_LOGIN_CAP
939 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
942 if (stat(buf, &st) >= 0)
949 * Sets the value of the given variable in the environment. If the variable
950 * already exists, its value is overridden.
953 child_set_env(char ***envp, u_int *envsizep, const char *name,
961 * If we're passed an uninitialized list, allocate a single null
962 * entry before continuing.
964 if (*envp == NULL && *envsizep == 0) {
965 *envp = xmalloc(sizeof(char *));
971 * Find the slot where the value should be stored. If the variable
972 * already exists, we reuse the slot; otherwise we append a new slot
973 * at the end of the array, expanding if necessary.
976 namelen = strlen(name);
977 for (i = 0; env[i]; i++)
978 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
981 /* Reuse the slot. */
984 /* New variable. Expand if necessary. */
986 if (i >= envsize - 1) {
988 fatal("child_set_env: too many env vars");
990 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
993 /* Need to set the NULL pointer at end of array beyond the new slot. */
997 /* Allocate space and format the variable in the appropriate slot. */
998 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
999 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1003 * Reads environment variables from the given file and adds/overrides them
1004 * into the environment. If the file does not exist, this does nothing.
1005 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1006 * and assignments of the form name=value. No other forms are allowed.
1009 read_environment_file(char ***env, u_int *envsize,
1010 const char *filename)
1017 f = fopen(filename, "r");
1021 while (fgets(buf, sizeof(buf), f)) {
1022 if (++lineno > 1000)
1023 fatal("Too many lines in environment file %s", filename);
1024 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1026 if (!*cp || *cp == '#' || *cp == '\n')
1029 cp[strcspn(cp, "\n")] = '\0';
1031 value = strchr(cp, '=');
1032 if (value == NULL) {
1033 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1038 * Replace the equals sign by nul, and advance value to
1043 child_set_env(env, envsize, cp, value);
1048 #ifdef HAVE_ETC_DEFAULT_LOGIN
1050 * Return named variable from specified environment, or NULL if not present.
1053 child_get_env(char **env, const char *name)
1059 for (i=0; env[i] != NULL; i++)
1060 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1061 return(env[i] + len + 1);
1066 * Read /etc/default/login.
1067 * We pick up the PATH (or SUPATH for root) and UMASK.
1070 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1072 char **tmpenv = NULL, *var;
1073 u_int i, tmpenvsize = 0;
1077 * We don't want to copy the whole file to the child's environment,
1078 * so we use a temporary environment and copy the variables we're
1081 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1087 var = child_get_env(tmpenv, "SUPATH");
1089 var = child_get_env(tmpenv, "PATH");
1091 child_set_env(env, envsize, "PATH", var);
1093 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1094 if (sscanf(var, "%5lo", &mask) == 1)
1095 umask((mode_t)mask);
1097 for (i = 0; tmpenv[i] != NULL; i++)
1101 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1104 copy_environment(char **source, char ***env, u_int *envsize)
1106 char *var_name, *var_val;
1112 for(i = 0; source[i] != NULL; i++) {
1113 var_name = xstrdup(source[i]);
1114 if ((var_val = strstr(var_name, "=")) == NULL) {
1120 debug3("Copy environment: %s=%s", var_name, var_val);
1121 child_set_env(env, envsize, var_name, var_val);
1128 do_setup_env(Session *s, const char *shell)
1133 struct passwd *pw = s->pw;
1134 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1137 extern char **environ;
1141 /* Initialize the environment. */
1143 env = xcalloc(envsize, sizeof(char *));
1148 * The Windows environment contains some setting which are
1149 * important for a running system. They must not be dropped.
1154 p = fetch_windows_environment();
1155 copy_environment(p, &env, &envsize);
1156 free_windows_environment(p);
1161 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1164 /* Allow any GSSAPI methods that we've used to alter
1165 * the childs environment as they see fit
1167 ssh_gssapi_do_child(&env, &envsize);
1170 if (!options.use_login) {
1171 /* Set basic environment. */
1172 for (i = 0; i < s->num_env; i++)
1173 child_set_env(&env, &envsize, s->env[i].name,
1176 child_set_env(&env, &envsize, "USER", pw->pw_name);
1177 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1179 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1181 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1182 snprintf(buf, sizeof buf, "%.200s/%.50s",
1183 _PATH_MAILDIR, pw->pw_name);
1184 child_set_env(&env, &envsize, "MAIL", buf);
1185 #ifdef HAVE_LOGIN_CAP
1186 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1187 child_set_env(&env, &envsize, "TERM", "su");
1189 environ = xmalloc(sizeof(char *));
1191 (void) setusercontext(lc, pw, pw->pw_uid,
1192 LOGIN_SETENV|LOGIN_SETPATH);
1193 copy_environment(environ, &env, &envsize);
1194 for (var = environ; *var != NULL; ++var)
1198 #else /* HAVE_LOGIN_CAP */
1199 # ifndef HAVE_CYGWIN
1201 * There's no standard path on Windows. The path contains
1202 * important components pointing to the system directories,
1203 * needed for loading shared libraries. So the path better
1204 * remains intact here.
1206 # ifdef HAVE_ETC_DEFAULT_LOGIN
1207 read_etc_default_login(&env, &envsize, pw->pw_uid);
1208 path = child_get_env(env, "PATH");
1209 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1210 if (path == NULL || *path == '\0') {
1211 child_set_env(&env, &envsize, "PATH",
1212 s->pw->pw_uid == 0 ?
1213 SUPERUSER_PATH : _PATH_STDPATH);
1215 # endif /* HAVE_CYGWIN */
1216 #endif /* HAVE_LOGIN_CAP */
1218 /* Normal systems set SHELL by default. */
1219 child_set_env(&env, &envsize, "SHELL", shell);
1222 /* Set custom environment options from RSA authentication. */
1223 if (!options.use_login) {
1224 while (custom_environment) {
1225 struct envstring *ce = custom_environment;
1228 for (i = 0; str[i] != '=' && str[i]; i++)
1230 if (str[i] == '=') {
1232 child_set_env(&env, &envsize, str, str + i + 1);
1234 custom_environment = ce->next;
1240 /* SSH_CLIENT deprecated */
1241 snprintf(buf, sizeof buf, "%.50s %d %d",
1242 get_remote_ipaddr(), get_remote_port(), get_local_port());
1243 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1245 laddr = get_local_ipaddr(packet_get_connection_in());
1246 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1247 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1249 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1252 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1254 child_set_env(&env, &envsize, "TERM", s->term);
1256 child_set_env(&env, &envsize, "DISPLAY", s->display);
1257 if (original_command)
1258 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1262 if (cray_tmpdir[0] != '\0')
1263 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1264 #endif /* _UNICOS */
1267 * Since we clear KRB5CCNAME at startup, if it's set now then it
1268 * must have been set by a native authentication method (eg AIX or
1269 * SIA), so copy it to the child.
1274 if ((cp = getenv("KRB5CCNAME")) != NULL)
1275 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1282 if ((cp = getenv("AUTHSTATE")) != NULL)
1283 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1284 read_environment_file(&env, &envsize, "/etc/environment");
1288 if (s->authctxt->krb5_ccname)
1289 child_set_env(&env, &envsize, "KRB5CCNAME",
1290 s->authctxt->krb5_ccname);
1294 * Pull in any environment variables that may have
1297 if (options.use_pam) {
1300 p = fetch_pam_child_environment();
1301 copy_environment(p, &env, &envsize);
1302 free_pam_environment(p);
1304 p = fetch_pam_environment();
1305 copy_environment(p, &env, &envsize);
1306 free_pam_environment(p);
1308 #endif /* USE_PAM */
1310 if (auth_sock_name != NULL)
1311 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1314 /* read $HOME/.ssh/environment. */
1315 if (options.permit_user_env && !options.use_login) {
1316 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1317 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1318 read_environment_file(&env, &envsize, buf);
1321 /* dump the environment */
1322 fprintf(stderr, "Environment:\n");
1323 for (i = 0; env[i]; i++)
1324 fprintf(stderr, " %.200s\n", env[i]);
1330 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1331 * first in this order).
1334 do_rc_files(Session *s, const char *shell)
1342 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1344 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1345 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1346 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1347 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1348 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1350 fprintf(stderr, "Running %s\n", cmd);
1351 f = popen(cmd, "w");
1354 fprintf(f, "%s %s\n", s->auth_proto,
1358 fprintf(stderr, "Could not run %s\n",
1360 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1362 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1363 _PATH_SSH_SYSTEM_RC);
1364 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1367 fprintf(f, "%s %s\n", s->auth_proto,
1371 fprintf(stderr, "Could not run %s\n",
1372 _PATH_SSH_SYSTEM_RC);
1373 } else if (do_xauth && options.xauth_location != NULL) {
1374 /* Add authority data to .Xauthority if appropriate. */
1377 "Running %.500s remove %.100s\n",
1378 options.xauth_location, s->auth_display);
1380 "%.500s add %.100s %.100s %.100s\n",
1381 options.xauth_location, s->auth_display,
1382 s->auth_proto, s->auth_data);
1384 snprintf(cmd, sizeof cmd, "%s -q -",
1385 options.xauth_location);
1386 f = popen(cmd, "w");
1388 fprintf(f, "remove %s\n",
1390 fprintf(f, "add %s %s %s\n",
1391 s->auth_display, s->auth_proto,
1395 fprintf(stderr, "Could not run %s\n",
1402 do_nologin(struct passwd *pw)
1405 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1408 #ifdef HAVE_LOGIN_CAP
1409 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1411 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1413 if (pw->pw_uid == 0)
1417 if (stat(nl, &sb) == -1) {
1423 /* /etc/nologin exists. Print its contents if we can and exit. */
1424 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1425 if ((f = fopen(nl, "r")) != NULL) {
1426 while (fgets(buf, sizeof(buf), f))
1434 * Chroot into a directory after checking it for safety: all path components
1435 * must be root-owned directories with strict permissions.
1438 safely_chroot(const char *path, uid_t uid)
1441 char component[MAXPATHLEN];
1445 fatal("chroot path does not begin at root");
1446 if (strlen(path) >= sizeof(component))
1447 fatal("chroot path too long");
1450 * Descend the path, checking that each component is a
1451 * root-owned directory with strict permissions.
1453 for (cp = path; cp != NULL;) {
1454 if ((cp = strchr(cp, '/')) == NULL)
1455 strlcpy(component, path, sizeof(component));
1458 memcpy(component, path, cp - path);
1459 component[cp - path] = '\0';
1462 debug3("%s: checking '%s'", __func__, component);
1464 if (stat(component, &st) != 0)
1465 fatal("%s: stat(\"%s\"): %s", __func__,
1466 component, strerror(errno));
1467 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1468 fatal("bad ownership or modes for chroot "
1469 "directory %s\"%s\"",
1470 cp == NULL ? "" : "component ", component);
1471 if (!S_ISDIR(st.st_mode))
1472 fatal("chroot path %s\"%s\" is not a directory",
1473 cp == NULL ? "" : "component ", component);
1477 if (chdir(path) == -1)
1478 fatal("Unable to chdir to chroot path \"%s\": "
1479 "%s", path, strerror(errno));
1480 if (chroot(path) == -1)
1481 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1482 if (chdir("/") == -1)
1483 fatal("%s: chdir(/) after chroot: %s",
1484 __func__, strerror(errno));
1485 verbose("Changed root directory to \"%s\"", path);
1488 /* Set login name, uid, gid, and groups. */
1490 do_setusercontext(struct passwd *pw)
1492 char *chroot_path, *tmp;
1494 platform_setusercontext(pw);
1496 if (platform_privileged_uidswap()) {
1497 #ifdef HAVE_LOGIN_CAP
1498 if (setusercontext(lc, pw, pw->pw_uid,
1499 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1500 perror("unable to set user context");
1504 if (setlogin(pw->pw_name) < 0)
1505 error("setlogin failed: %s", strerror(errno));
1506 if (setgid(pw->pw_gid) < 0) {
1510 /* Initialize the group list. */
1511 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1512 perror("initgroups");
1518 platform_setusercontext_post_groups(pw);
1520 if (options.chroot_directory != NULL &&
1521 strcasecmp(options.chroot_directory, "none") != 0) {
1522 tmp = tilde_expand_filename(options.chroot_directory,
1524 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1525 "u", pw->pw_name, (char *)NULL);
1526 safely_chroot(chroot_path, pw->pw_uid);
1531 #ifdef HAVE_LOGIN_CAP
1532 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1533 perror("unable to set user context (setuser)");
1537 /* Permanently switch to the desired uid. */
1538 permanently_set_uid(pw);
1542 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1543 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1547 do_pwchange(Session *s)
1550 fprintf(stderr, "WARNING: Your password has expired.\n");
1551 if (s->ttyfd != -1) {
1553 "You must change your password now and login again!\n");
1557 #ifdef PASSWD_NEEDS_USERNAME
1558 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1561 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1566 "Password change required but no TTY available.\n");
1572 launch_login(struct passwd *pw, const char *hostname)
1574 /* Launch login(1). */
1576 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1577 #ifdef xxxLOGIN_NEEDS_TERM
1578 (s->term ? s->term : "unknown"),
1579 #endif /* LOGIN_NEEDS_TERM */
1580 #ifdef LOGIN_NO_ENDOPT
1581 "-p", "-f", pw->pw_name, (char *)NULL);
1583 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1586 /* Login couldn't be executed, die. */
1593 child_close_fds(void)
1595 if (packet_get_connection_in() == packet_get_connection_out())
1596 close(packet_get_connection_in());
1598 close(packet_get_connection_in());
1599 close(packet_get_connection_out());
1602 * Close all descriptors related to channels. They will still remain
1603 * open in the parent.
1605 /* XXX better use close-on-exec? -markus */
1606 channel_close_all();
1609 * Close any extra file descriptors. Note that there may still be
1610 * descriptors left by system functions. They will be closed later.
1615 * Close any extra open file descriptors so that we don't have them
1616 * hanging around in clients. Note that we want to do this after
1617 * initgroups, because at least on Solaris 2.3 it leaves file
1620 closefrom(STDERR_FILENO + 1);
1624 * Performs common processing for the child, such as setting up the
1625 * environment, closing extra file descriptors, setting the user and group
1626 * ids, and executing the command or shell.
1630 do_child(Session *s, const char *command)
1632 extern char **environ;
1634 char *argv[ARGV_MAX];
1635 const char *shell, *shell0, *hostname = NULL;
1636 struct passwd *pw = s->pw;
1639 /* remove hostkey from the child's memory */
1640 destroy_sensitive_data();
1642 /* Force a password change */
1643 if (s->authctxt->force_pwchange) {
1644 do_setusercontext(pw);
1650 /* login(1) is only called if we execute the login shell */
1651 if (options.use_login && command != NULL)
1652 options.use_login = 0;
1655 cray_setup(pw->pw_uid, pw->pw_name, command);
1656 #endif /* _UNICOS */
1659 * Login(1) does this as well, and it needs uid 0 for the "-h"
1660 * switch, so we let login(1) to this for us.
1662 if (!options.use_login) {
1664 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1665 if (!check_quietlogin(s, command))
1667 #else /* HAVE_OSF_SIA */
1668 /* When PAM is enabled we rely on it to do the nologin check */
1669 if (!options.use_pam)
1671 do_setusercontext(pw);
1673 * PAM session modules in do_setusercontext may have
1674 * generated messages, so if this in an interactive
1675 * login then display them too.
1677 if (!check_quietlogin(s, command))
1679 #endif /* HAVE_OSF_SIA */
1683 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1684 debug3("PAM session not opened, exiting");
1691 * Get the shell from the password data. An empty shell field is
1692 * legal, and means /bin/sh.
1694 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1697 * Make sure $SHELL points to the shell from the password file,
1698 * even if shell is overridden from login.conf
1700 env = do_setup_env(s, shell);
1702 #ifdef HAVE_LOGIN_CAP
1703 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1706 /* we have to stash the hostname before we close our socket. */
1707 if (options.use_login)
1708 hostname = get_remote_name_or_ip(utmp_len,
1711 * Close the connection descriptors; note that this is the child, and
1712 * the server will still have the socket open, and it is important
1713 * that we do not shutdown it. Note that the descriptors cannot be
1714 * closed before building the environment, as we call
1715 * get_remote_ipaddr there.
1720 * Must take new environment into use so that .ssh/rc,
1721 * /etc/ssh/sshrc and xauth are run in the proper environment.
1725 #if defined(KRB5) && defined(USE_AFS)
1727 * At this point, we check to see if AFS is active and if we have
1728 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1729 * if we can (and need to) extend the ticket into an AFS token. If
1730 * we don't do this, we run into potential problems if the user's
1731 * home directory is in AFS and it's not world-readable.
1734 if (options.kerberos_get_afs_token && k_hasafs() &&
1735 (s->authctxt->krb5_ctx != NULL)) {
1738 debug("Getting AFS token");
1742 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1743 krb5_afslog(s->authctxt->krb5_ctx,
1744 s->authctxt->krb5_fwd_ccache, cell, NULL);
1746 krb5_afslog_home(s->authctxt->krb5_ctx,
1747 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1751 /* Change current directory to the user's home directory. */
1752 if (chdir(pw->pw_dir) < 0) {
1753 /* Suppress missing homedir warning for chroot case */
1754 #ifdef HAVE_LOGIN_CAP
1755 r = login_getcapbool(lc, "requirehome", 0);
1757 if (r || options.chroot_directory == NULL ||
1758 strcasecmp(options.chroot_directory, "none") == 0)
1759 fprintf(stderr, "Could not chdir to home "
1760 "directory %s: %s\n", pw->pw_dir,
1766 closefrom(STDERR_FILENO + 1);
1768 if (!options.use_login)
1769 do_rc_files(s, shell);
1771 /* restore SIGPIPE for child */
1772 signal(SIGPIPE, SIG_DFL);
1774 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1775 printf("This service allows sftp connections only.\n");
1778 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1779 extern int optind, optreset;
1783 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1784 args = xstrdup(command ? command : "sftp-server");
1785 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1786 if (i < ARGV_MAX - 1)
1789 optind = optreset = 1;
1790 __progname = argv[0];
1792 ssh_selinux_change_context("sftpd_t");
1794 exit(sftp_server_main(i, argv, s->pw));
1799 if (options.use_login) {
1800 launch_login(pw, hostname);
1804 /* Get the last component of the shell name. */
1805 if ((shell0 = strrchr(shell, '/')) != NULL)
1811 * If we have no command, execute the shell. In this case, the shell
1812 * name to be passed in argv[0] is preceded by '-' to indicate that
1813 * this is a login shell.
1818 /* Start the shell. Set initial character to '-'. */
1821 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1822 >= sizeof(argv0) - 1) {
1828 /* Execute the shell. */
1831 execve(shell, argv, env);
1833 /* Executing the shell failed. */
1838 * Execute the command using the user's shell. This uses the -c
1839 * option to execute the command.
1841 argv[0] = (char *) shell0;
1843 argv[2] = (char *) command;
1845 execve(shell, argv, env);
1851 session_unused(int id)
1853 debug3("%s: session id %d unused", __func__, id);
1854 if (id >= options.max_sessions ||
1855 id >= sessions_nalloc) {
1856 fatal("%s: insane session id %d (max %d nalloc %d)",
1857 __func__, id, options.max_sessions, sessions_nalloc);
1859 bzero(&sessions[id], sizeof(*sessions));
1860 sessions[id].self = id;
1861 sessions[id].used = 0;
1862 sessions[id].chanid = -1;
1863 sessions[id].ptyfd = -1;
1864 sessions[id].ttyfd = -1;
1865 sessions[id].ptymaster = -1;
1866 sessions[id].x11_chanids = NULL;
1867 sessions[id].next_unused = sessions_first_unused;
1868 sessions_first_unused = id;
1876 if (sessions_first_unused == -1) {
1877 if (sessions_nalloc >= options.max_sessions)
1879 debug2("%s: allocate (allocated %d max %d)",
1880 __func__, sessions_nalloc, options.max_sessions);
1881 tmp = xrealloc(sessions, sessions_nalloc + 1,
1884 error("%s: cannot allocate %d sessions",
1885 __func__, sessions_nalloc + 1);
1889 session_unused(sessions_nalloc++);
1892 if (sessions_first_unused >= sessions_nalloc ||
1893 sessions_first_unused < 0) {
1894 fatal("%s: insane first_unused %d max %d nalloc %d",
1895 __func__, sessions_first_unused, options.max_sessions,
1899 s = &sessions[sessions_first_unused];
1901 fatal("%s: session %d already used",
1902 __func__, sessions_first_unused);
1904 sessions_first_unused = s->next_unused;
1906 s->next_unused = -1;
1907 debug("session_new: session %d", s->self);
1916 for (i = 0; i < sessions_nalloc; i++) {
1917 Session *s = &sessions[i];
1919 debug("dump: used %d next_unused %d session %d %p "
1920 "channel %d pid %ld",
1931 session_open(Authctxt *authctxt, int chanid)
1933 Session *s = session_new();
1934 debug("session_open: channel %d", chanid);
1936 error("no more sessions");
1939 s->authctxt = authctxt;
1940 s->pw = authctxt->pw;
1941 if (s->pw == NULL || !authctxt->valid)
1942 fatal("no user for session %d", s->self);
1943 debug("session_open: session %d: link with channel %d", s->self, chanid);
1949 session_by_tty(char *tty)
1952 for (i = 0; i < sessions_nalloc; i++) {
1953 Session *s = &sessions[i];
1954 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1955 debug("session_by_tty: session %d tty %s", i, tty);
1959 debug("session_by_tty: unknown tty %.100s", tty);
1965 session_by_channel(int id)
1968 for (i = 0; i < sessions_nalloc; i++) {
1969 Session *s = &sessions[i];
1970 if (s->used && s->chanid == id) {
1971 debug("session_by_channel: session %d channel %d",
1976 debug("session_by_channel: unknown channel %d", id);
1982 session_by_x11_channel(int id)
1986 for (i = 0; i < sessions_nalloc; i++) {
1987 Session *s = &sessions[i];
1989 if (s->x11_chanids == NULL || !s->used)
1991 for (j = 0; s->x11_chanids[j] != -1; j++) {
1992 if (s->x11_chanids[j] == id) {
1993 debug("session_by_x11_channel: session %d "
1994 "channel %d", s->self, id);
1999 debug("session_by_x11_channel: unknown channel %d", id);
2005 session_by_pid(pid_t pid)
2008 debug("session_by_pid: pid %ld", (long)pid);
2009 for (i = 0; i < sessions_nalloc; i++) {
2010 Session *s = &sessions[i];
2011 if (s->used && s->pid == pid)
2014 error("session_by_pid: unknown pid %ld", (long)pid);
2020 session_window_change_req(Session *s)
2022 s->col = packet_get_int();
2023 s->row = packet_get_int();
2024 s->xpixel = packet_get_int();
2025 s->ypixel = packet_get_int();
2027 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2032 session_pty_req(Session *s)
2038 debug("Allocating a pty not permitted for this authentication.");
2041 if (s->ttyfd != -1) {
2042 packet_disconnect("Protocol error: you already have a pty.");
2046 s->term = packet_get_string(&len);
2049 s->col = packet_get_int();
2050 s->row = packet_get_int();
2052 s->row = packet_get_int();
2053 s->col = packet_get_int();
2055 s->xpixel = packet_get_int();
2056 s->ypixel = packet_get_int();
2058 if (strcmp(s->term, "") == 0) {
2063 /* Allocate a pty and open it. */
2064 debug("Allocating pty.");
2065 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2072 error("session_pty_req: session %d alloc failed", s->self);
2075 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2077 /* for SSH1 the tty modes length is not given */
2079 n_bytes = packet_remaining();
2080 tty_parse_modes(s->ttyfd, &n_bytes);
2083 pty_setowner(s->pw, s->tty);
2085 /* Set window size from the packet. */
2086 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2089 session_proctitle(s);
2094 session_subsystem_req(Session *s)
2099 char *prog, *cmd, *subsys = packet_get_string(&len);
2103 logit("subsystem request for %.100s by user %s", subsys,
2106 for (i = 0; i < options.num_subsystems; i++) {
2107 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2108 prog = options.subsystem_command[i];
2109 cmd = options.subsystem_args[i];
2110 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2111 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2112 debug("subsystem: %s", prog);
2114 if (stat(prog, &st) < 0)
2115 debug("subsystem: cannot stat %s: %s",
2116 prog, strerror(errno));
2117 s->is_subsystem = SUBSYSTEM_EXT;
2118 debug("subsystem: exec() %s", cmd);
2120 success = do_exec(s, cmd) == 0;
2126 logit("subsystem request for %.100s failed, subsystem not found",
2134 session_x11_req(Session *s)
2138 if (s->auth_proto != NULL || s->auth_data != NULL) {
2139 error("session_x11_req: session %d: "
2140 "x11 forwarding already active", s->self);
2143 s->single_connection = packet_get_char();
2144 s->auth_proto = packet_get_string(NULL);
2145 s->auth_data = packet_get_string(NULL);
2146 s->screen = packet_get_int();
2149 success = session_setup_x11fwd(s);
2151 xfree(s->auth_proto);
2152 xfree(s->auth_data);
2153 s->auth_proto = NULL;
2154 s->auth_data = NULL;
2160 session_shell_req(Session *s)
2163 return do_exec(s, NULL) == 0;
2167 session_exec_req(Session *s)
2171 char *command = packet_get_string(&len);
2173 success = do_exec(s, command) == 0;
2179 session_break_req(Session *s)
2182 packet_get_int(); /* ignored */
2185 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2191 session_env_req(Session *s)
2194 u_int name_len, val_len, i;
2196 name = packet_get_string(&name_len);
2197 val = packet_get_string(&val_len);
2200 /* Don't set too many environment variables */
2201 if (s->num_env > 128) {
2202 debug2("Ignoring env request %s: too many env vars", name);
2206 for (i = 0; i < options.num_accept_env; i++) {
2207 if (match_pattern(name, options.accept_env[i])) {
2208 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2209 s->env = xrealloc(s->env, s->num_env + 1,
2211 s->env[s->num_env].name = name;
2212 s->env[s->num_env].val = val;
2217 debug2("Ignoring env request %s: disallowed name", name);
2226 session_auth_agent_req(Session *s)
2228 static int called = 0;
2230 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2231 debug("session_auth_agent_req: no_agent_forwarding_flag");
2238 return auth_input_request_forwarding(s->pw);
2243 session_input_channel_req(Channel *c, const char *rtype)
2248 if ((s = session_by_channel(c->self)) == NULL) {
2249 logit("session_input_channel_req: no session %d req %.100s",
2253 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2256 * a session is in LARVAL state until a shell, a command
2257 * or a subsystem is executed
2259 if (c->type == SSH_CHANNEL_LARVAL) {
2260 if (strcmp(rtype, "shell") == 0) {
2261 success = session_shell_req(s);
2262 } else if (strcmp(rtype, "exec") == 0) {
2263 success = session_exec_req(s);
2264 } else if (strcmp(rtype, "pty-req") == 0) {
2265 success = session_pty_req(s);
2266 } else if (strcmp(rtype, "x11-req") == 0) {
2267 success = session_x11_req(s);
2268 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2269 success = session_auth_agent_req(s);
2270 } else if (strcmp(rtype, "subsystem") == 0) {
2271 success = session_subsystem_req(s);
2272 } else if (strcmp(rtype, "env") == 0) {
2273 success = session_env_req(s);
2276 if (strcmp(rtype, "window-change") == 0) {
2277 success = session_window_change_req(s);
2278 } else if (strcmp(rtype, "break") == 0) {
2279 success = session_break_req(s);
2286 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2290 fatal("session_set_fds: called for proto != 2.0");
2292 * now that have a child and a pipe to the child,
2293 * we can activate our channel and register the fd's
2295 if (s->chanid == -1)
2296 fatal("no channel for session %d", s->self);
2297 if (options.hpn_disabled)
2298 channel_set_fds(s->chanid, fdout, fdin, fderr,
2299 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2300 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2302 channel_set_fds(s->chanid, fdout, fdin, fderr,
2303 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2304 1, is_tty, options.hpn_buffer_size);
2308 * Function to perform pty cleanup. Also called if we get aborted abnormally
2309 * (e.g., due to a dropped connection).
2312 session_pty_cleanup2(Session *s)
2315 error("session_pty_cleanup: no session");
2321 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2323 /* Record that the user has logged out. */
2325 record_logout(s->pid, s->tty, s->pw->pw_name);
2327 /* Release the pseudo-tty. */
2329 pty_release(s->tty);
2332 * Close the server side of the socket pairs. We must do this after
2333 * the pty cleanup, so that another process doesn't get this pty
2334 * while we're still cleaning up.
2336 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2337 error("close(s->ptymaster/%d): %s",
2338 s->ptymaster, strerror(errno));
2340 /* unlink pty from session */
2345 session_pty_cleanup(Session *s)
2347 PRIVSEP(session_pty_cleanup2(s));
2353 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2368 return "SIG@openssh.com";
2372 session_close_x11(int id)
2376 if ((c = channel_by_id(id)) == NULL) {
2377 debug("session_close_x11: x11 channel %d missing", id);
2379 /* Detach X11 listener */
2380 debug("session_close_x11: detach x11 channel %d", id);
2381 channel_cancel_cleanup(id);
2382 if (c->ostate != CHAN_OUTPUT_CLOSED)
2388 session_close_single_x11(int id, void *arg)
2393 debug3("session_close_single_x11: channel %d", id);
2394 channel_cancel_cleanup(id);
2395 if ((s = session_by_x11_channel(id)) == NULL)
2396 fatal("session_close_single_x11: no x11 channel %d", id);
2397 for (i = 0; s->x11_chanids[i] != -1; i++) {
2398 debug("session_close_single_x11: session %d: "
2399 "closing channel %d", s->self, s->x11_chanids[i]);
2401 * The channel "id" is already closing, but make sure we
2402 * close all of its siblings.
2404 if (s->x11_chanids[i] != id)
2405 session_close_x11(s->x11_chanids[i]);
2407 xfree(s->x11_chanids);
2408 s->x11_chanids = NULL;
2413 if (s->auth_proto) {
2414 xfree(s->auth_proto);
2415 s->auth_proto = NULL;
2418 xfree(s->auth_data);
2419 s->auth_data = NULL;
2421 if (s->auth_display) {
2422 xfree(s->auth_display);
2423 s->auth_display = NULL;
2428 session_exit_message(Session *s, int status)
2432 if ((c = channel_lookup(s->chanid)) == NULL)
2433 fatal("session_exit_message: session %d: no channel %d",
2434 s->self, s->chanid);
2435 debug("session_exit_message: session %d channel %d pid %ld",
2436 s->self, s->chanid, (long)s->pid);
2438 if (WIFEXITED(status)) {
2439 channel_request_start(s->chanid, "exit-status", 0);
2440 packet_put_int(WEXITSTATUS(status));
2442 } else if (WIFSIGNALED(status)) {
2443 channel_request_start(s->chanid, "exit-signal", 0);
2444 packet_put_cstring(sig2name(WTERMSIG(status)));
2446 packet_put_char(WCOREDUMP(status)? 1 : 0);
2447 #else /* WCOREDUMP */
2449 #endif /* WCOREDUMP */
2450 packet_put_cstring("");
2451 packet_put_cstring("");
2454 /* Some weird exit cause. Just exit. */
2455 packet_disconnect("wait returned status %04x.", status);
2458 /* disconnect channel */
2459 debug("session_exit_message: release channel %d", s->chanid);
2462 * Adjust cleanup callback attachment to send close messages when
2463 * the channel gets EOF. The session will be then be closed
2464 * by session_close_by_channel when the childs close their fds.
2466 channel_register_cleanup(c->self, session_close_by_channel, 1);
2469 * emulate a write failure with 'chan_write_failed', nobody will be
2470 * interested in data we write.
2471 * Note that we must not call 'chan_read_failed', since there could
2472 * be some more data waiting in the pipe.
2474 if (c->ostate != CHAN_OUTPUT_CLOSED)
2475 chan_write_failed(c);
2479 session_close(Session *s)
2483 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2485 session_pty_cleanup(s);
2491 xfree(s->x11_chanids);
2492 if (s->auth_display)
2493 xfree(s->auth_display);
2495 xfree(s->auth_data);
2497 xfree(s->auth_proto);
2498 if (s->env != NULL) {
2499 for (i = 0; i < s->num_env; i++) {
2500 xfree(s->env[i].name);
2501 xfree(s->env[i].val);
2505 session_proctitle(s);
2506 session_unused(s->self);
2510 session_close_by_pid(pid_t pid, int status)
2512 Session *s = session_by_pid(pid);
2514 debug("session_close_by_pid: no session for pid %ld",
2518 if (s->chanid != -1)
2519 session_exit_message(s, status);
2521 session_pty_cleanup(s);
2526 * this is called when a channel dies before
2527 * the session 'child' itself dies
2530 session_close_by_channel(int id, void *arg)
2532 Session *s = session_by_channel(id);
2536 debug("session_close_by_channel: no session for id %d", id);
2539 debug("session_close_by_channel: channel %d child %ld",
2542 debug("session_close_by_channel: channel %d: has child", id);
2544 * delay detach of session, but release pty, since
2545 * the fd's to the child are already closed
2548 session_pty_cleanup(s);
2551 /* detach by removing callback */
2552 channel_cancel_cleanup(s->chanid);
2554 /* Close any X11 listeners associated with this session */
2555 if (s->x11_chanids != NULL) {
2556 for (i = 0; s->x11_chanids[i] != -1; i++) {
2557 session_close_x11(s->x11_chanids[i]);
2558 s->x11_chanids[i] = -1;
2567 session_destroy_all(void (*closefunc)(Session *))
2570 for (i = 0; i < sessions_nalloc; i++) {
2571 Session *s = &sessions[i];
2573 if (closefunc != NULL)
2582 session_tty_list(void)
2584 static char buf[1024];
2589 for (i = 0; i < sessions_nalloc; i++) {
2590 Session *s = &sessions[i];
2591 if (s->used && s->ttyfd != -1) {
2593 if (strncmp(s->tty, "/dev/", 5) != 0) {
2594 cp = strrchr(s->tty, '/');
2595 cp = (cp == NULL) ? s->tty : cp + 1;
2600 strlcat(buf, ",", sizeof buf);
2601 strlcat(buf, cp, sizeof buf);
2605 strlcpy(buf, "notty", sizeof buf);
2610 session_proctitle(Session *s)
2613 error("no user for session %d", s->self);
2615 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2619 session_setup_x11fwd(Session *s)
2622 char display[512], auth_display[512];
2623 char hostname[MAXHOSTNAMELEN];
2626 if (no_x11_forwarding_flag) {
2627 packet_send_debug("X11 forwarding disabled in user configuration file.");
2630 if (!options.x11_forwarding) {
2631 debug("X11 forwarding disabled in server configuration file.");
2634 if (!options.xauth_location ||
2635 (stat(options.xauth_location, &st) == -1)) {
2636 packet_send_debug("No xauth program; cannot forward with spoofing.");
2639 if (options.use_login) {
2640 packet_send_debug("X11 forwarding disabled; "
2641 "not compatible with UseLogin=yes.");
2644 if (s->display != NULL) {
2645 debug("X11 display already set.");
2648 if (x11_create_display_inet(options.x11_display_offset,
2649 options.x11_use_localhost, s->single_connection,
2650 &s->display_number, &s->x11_chanids) == -1) {
2651 debug("x11_create_display_inet failed.");
2654 for (i = 0; s->x11_chanids[i] != -1; i++) {
2655 channel_register_cleanup(s->x11_chanids[i],
2656 session_close_single_x11, 0);
2659 /* Set up a suitable value for the DISPLAY variable. */
2660 if (gethostname(hostname, sizeof(hostname)) < 0)
2661 fatal("gethostname: %.100s", strerror(errno));
2663 * auth_display must be used as the displayname when the
2664 * authorization entry is added with xauth(1). This will be
2665 * different than the DISPLAY string for localhost displays.
2667 if (options.x11_use_localhost) {
2668 snprintf(display, sizeof display, "localhost:%u.%u",
2669 s->display_number, s->screen);
2670 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2671 s->display_number, s->screen);
2672 s->display = xstrdup(display);
2673 s->auth_display = xstrdup(auth_display);
2675 #ifdef IPADDR_IN_DISPLAY
2677 struct in_addr my_addr;
2679 he = gethostbyname(hostname);
2681 error("Can't get IP address for X11 DISPLAY.");
2682 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2685 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2686 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2687 s->display_number, s->screen);
2689 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2690 s->display_number, s->screen);
2692 s->display = xstrdup(display);
2693 s->auth_display = xstrdup(display);
2700 do_authenticated2(Authctxt *authctxt)
2702 server_loop2(authctxt);
2706 do_cleanup(Authctxt *authctxt)
2708 static int called = 0;
2710 debug("do_cleanup");
2712 /* no cleanup if we're in the child for login shell */
2716 /* avoid double cleanup */
2721 if (authctxt == NULL)
2725 if (options.use_pam) {
2727 sshpam_thread_cleanup();
2731 if (!authctxt->authenticated)
2735 if (options.kerberos_ticket_cleanup &&
2737 krb5_cleanup_proc(authctxt);
2741 if (compat20 && options.gss_cleanup_creds)
2742 ssh_gssapi_cleanup_creds();
2745 /* remove agent socket */
2746 auth_sock_cleanup_proc(authctxt->pw);
2749 * Cleanup ptys/utmp only if privsep is disabled,
2750 * or if running in monitor.
2752 if (!use_privsep || mm_is_monitor())
2753 session_destroy_all(session_pty_cleanup2);