1 /* $OpenBSD: session.c,v 1.270 2014/01/31 16:39:19 tedu 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>
66 #include "openbsd-compat/sys-queue.h"
85 #include "auth-options.h"
87 #include "pathnames.h"
91 #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;
165 /* Name and directory of socket for authentication agent forwarding. */
166 static char *auth_sock_name = NULL;
167 static char *auth_sock_dir = NULL;
169 /* removes the agent forwarding socket */
172 auth_sock_cleanup_proc(struct passwd *pw)
174 if (auth_sock_name != NULL) {
175 temporarily_use_uid(pw);
176 unlink(auth_sock_name);
177 rmdir(auth_sock_dir);
178 auth_sock_name = NULL;
184 auth_input_request_forwarding(struct passwd * pw)
188 struct sockaddr_un sunaddr;
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 /* Create the socket. */
215 sock = socket(AF_UNIX, SOCK_STREAM, 0);
217 error("socket: %.100s", strerror(errno));
222 /* Bind it to the name. */
223 memset(&sunaddr, 0, sizeof(sunaddr));
224 sunaddr.sun_family = AF_UNIX;
225 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
227 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
228 error("bind: %.100s", strerror(errno));
233 /* Restore the privileged uid. */
236 /* Start listening on the socket. */
237 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
238 error("listen: %.100s", strerror(errno));
243 * Allocate a channel for the authentication agent socket.
244 * Ignore HPN on that one given no improvement expected.
246 nc = channel_new("auth socket",
247 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
248 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
249 0, "auth socket", 1);
250 nc->path = xstrdup(auth_sock_name);
254 free(auth_sock_name);
255 if (auth_sock_dir != NULL) {
256 rmdir(auth_sock_dir);
261 auth_sock_name = NULL;
262 auth_sock_dir = NULL;
267 display_loginmsg(void)
269 if (buffer_len(&loginmsg) > 0) {
270 buffer_append(&loginmsg, "\0", 1);
271 printf("%s", (char *)buffer_ptr(&loginmsg));
272 buffer_clear(&loginmsg);
277 do_authenticated(Authctxt *authctxt)
279 setproctitle("%s", authctxt->pw->pw_name);
281 /* setup the channel layer */
282 if (no_port_forwarding_flag ||
283 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
284 channel_disable_adm_local_opens();
286 channel_permit_all_opens();
291 do_authenticated2(authctxt);
293 do_authenticated1(authctxt);
295 do_cleanup(authctxt);
298 /* Check untrusted xauth strings for metacharacters */
300 xauth_valid_string(const char *s)
304 for (i = 0; s[i] != '\0'; i++) {
305 if (!isalnum((u_char)s[i]) &&
306 s[i] != '.' && s[i] != ':' && s[i] != '/' &&
307 s[i] != '-' && s[i] != '_')
314 * Prepares for an interactive session. This is called after the user has
315 * been successfully authenticated. During this message exchange, pseudo
316 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
317 * are requested, etc.
320 do_authenticated1(Authctxt *authctxt)
324 int success, type, screen_flag;
325 int enable_compression_after_reply = 0;
326 u_int proto_len, data_len, dlen, compression_level = 0;
330 error("no more sessions");
333 s->authctxt = authctxt;
334 s->pw = authctxt->pw;
337 * We stay in this loop until the client requests to execute a shell
343 /* Get a packet from the client. */
344 type = packet_read();
346 /* Process the packet. */
348 case SSH_CMSG_REQUEST_COMPRESSION:
349 compression_level = packet_get_int();
351 if (compression_level < 1 || compression_level > 9) {
352 packet_send_debug("Received invalid compression level %d.",
356 if (options.compression == COMP_NONE) {
357 debug2("compression disabled");
360 /* Enable compression after we have responded with SUCCESS. */
361 enable_compression_after_reply = 1;
365 case SSH_CMSG_REQUEST_PTY:
366 success = session_pty_req(s);
369 case SSH_CMSG_X11_REQUEST_FORWARDING:
370 s->auth_proto = packet_get_string(&proto_len);
371 s->auth_data = packet_get_string(&data_len);
373 screen_flag = packet_get_protocol_flags() &
374 SSH_PROTOFLAG_SCREEN_NUMBER;
375 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
377 if (packet_remaining() == 4) {
379 debug2("Buggy client: "
380 "X11 screen flag missing");
381 s->screen = packet_get_int();
386 if (xauth_valid_string(s->auth_proto) &&
387 xauth_valid_string(s->auth_data))
388 success = session_setup_x11fwd(s);
391 error("Invalid X11 forwarding data");
396 s->auth_proto = NULL;
401 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
402 if (!options.allow_agent_forwarding ||
403 no_agent_forwarding_flag || compat13) {
404 debug("Authentication agent forwarding not permitted for this authentication.");
407 debug("Received authentication agent forwarding request.");
408 success = auth_input_request_forwarding(s->pw);
411 case SSH_CMSG_PORT_FORWARD_REQUEST:
412 if (no_port_forwarding_flag) {
413 debug("Port forwarding not permitted for this authentication.");
416 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
417 debug("Port forwarding not permitted.");
420 debug("Received TCP/IP port forwarding request.");
421 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
422 options.gateway_ports) < 0) {
423 debug("Port forwarding failed.");
429 case SSH_CMSG_MAX_PACKET_SIZE:
430 if (packet_set_maxsize(packet_get_int()) > 0)
434 case SSH_CMSG_EXEC_SHELL:
435 case SSH_CMSG_EXEC_CMD:
436 if (type == SSH_CMSG_EXEC_CMD) {
437 command = packet_get_string(&dlen);
438 debug("Exec command '%.500s'", command);
439 if (do_exec(s, command) != 0)
441 "command execution failed");
444 if (do_exec(s, NULL) != 0)
446 "shell execution failed");
454 * Any unknown messages in this phase are ignored,
455 * and a failure message is returned.
457 logit("Unknown packet type received after authentication: %d", type);
459 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
463 /* Enable compression now that we have replied if appropriate. */
464 if (enable_compression_after_reply) {
465 enable_compression_after_reply = 0;
466 packet_start_compression(compression_level);
473 * This is called to fork and execute a command when we have no tty. This
474 * will call do_child from the child, and server_loop from the parent after
475 * setting up file descriptors and such.
478 do_exec_no_pty(Session *s, const char *command)
483 int pin[2], pout[2], perr[2];
486 fatal("do_exec_no_pty: no session");
488 /* Allocate pipes for communicating with the program. */
490 error("%s: pipe in: %.100s", __func__, strerror(errno));
493 if (pipe(pout) < 0) {
494 error("%s: pipe out: %.100s", __func__, strerror(errno));
499 if (pipe(perr) < 0) {
500 error("%s: pipe err: %.100s", __func__,
509 int inout[2], err[2];
512 fatal("do_exec_no_pty: no session");
514 /* Uses socket pairs to communicate with the program. */
515 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
516 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
519 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
520 error("%s: socketpair #2: %.100s", __func__,
528 session_proctitle(s);
530 /* Fork the child. */
531 switch ((pid = fork())) {
533 error("%s: fork: %.100s", __func__, strerror(errno));
551 /* Child. Reinitialize the log since the pid has changed. */
552 log_init(__progname, options.log_level,
553 options.log_facility, log_stderr);
556 * Create a new session and process group since the 4.4BSD
557 * setlogin() affects the entire process group.
560 error("setsid failed: %.100s", strerror(errno));
564 * Redirect stdin. We close the parent side of the socket
565 * pair, and make the child side the standard input.
568 if (dup2(pin[0], 0) < 0)
569 perror("dup2 stdin");
572 /* Redirect stdout. */
574 if (dup2(pout[1], 1) < 0)
575 perror("dup2 stdout");
578 /* Redirect stderr. */
580 if (dup2(perr[1], 2) < 0)
581 perror("dup2 stderr");
585 * Redirect stdin, stdout, and stderr. Stdin and stdout will
586 * use the same socket, as some programs (particularly rdist)
587 * seem to depend on it.
591 if (dup2(inout[0], 0) < 0) /* stdin */
592 perror("dup2 stdin");
593 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
594 perror("dup2 stdout");
596 if (dup2(err[0], 2) < 0) /* stderr */
597 perror("dup2 stderr");
603 cray_init_job(s->pw); /* set up cray jid and tmpdir */
606 /* Do processing for the child (exec command etc). */
607 do_child(s, command);
614 signal(WJSIGNAL, cray_job_termination_handler);
617 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
621 /* Set interactive/non-interactive mode. */
622 packet_set_interactive(s->display != NULL,
623 options.ip_qos_interactive, options.ip_qos_bulk);
626 * Clear loginmsg, since it's the child's responsibility to display
627 * it to the user, otherwise multiple sessions may accumulate
628 * multiple copies of the login messages.
630 buffer_clear(&loginmsg);
633 /* We are the parent. Close the child sides of the pipes. */
639 session_set_fds(s, pin[1], pout[0], perr[0],
642 /* Enter the interactive session. */
643 server_loop(pid, pin[1], pout[0], perr[0]);
644 /* server_loop has closed pin[1], pout[0], and perr[0]. */
647 /* We are the parent. Close the child sides of the socket pairs. */
652 * Enter the interactive session. Note: server_loop must be able to
653 * handle the case that fdin and fdout are the same.
656 session_set_fds(s, inout[1], inout[1], err[1],
659 server_loop(pid, inout[1], inout[1], err[1]);
660 /* server_loop has closed inout[1] and err[1]. */
667 * This is called to fork and execute a command when we have a tty. This
668 * will call do_child from the child, and server_loop from the parent after
669 * setting up file descriptors, controlling tty, updating wtmp, utmp,
670 * lastlog, and other such operations.
673 do_exec_pty(Session *s, const char *command)
675 int fdout, ptyfd, ttyfd, ptymaster;
679 fatal("do_exec_pty: no session");
684 * Create another descriptor of the pty master side for use as the
685 * standard input. We could use the original descriptor, but this
686 * simplifies code in server_loop. The descriptor is bidirectional.
687 * Do this before forking (and cleanup in the child) so as to
688 * detect and gracefully fail out-of-fd conditions.
690 if ((fdout = dup(ptyfd)) < 0) {
691 error("%s: dup #1: %s", __func__, strerror(errno));
696 /* we keep a reference to the pty master */
697 if ((ptymaster = dup(ptyfd)) < 0) {
698 error("%s: dup #2: %s", __func__, strerror(errno));
705 /* Fork the child. */
706 switch ((pid = fork())) {
708 error("%s: fork: %.100s", __func__, strerror(errno));
720 /* Child. Reinitialize the log because the pid has changed. */
721 log_init(__progname, options.log_level,
722 options.log_facility, log_stderr);
723 /* Close the master side of the pseudo tty. */
726 /* Make the pseudo tty our controlling tty. */
727 pty_make_controlling_tty(&ttyfd, s->tty);
729 /* Redirect stdin/stdout/stderr from the pseudo tty. */
730 if (dup2(ttyfd, 0) < 0)
731 error("dup2 stdin: %s", strerror(errno));
732 if (dup2(ttyfd, 1) < 0)
733 error("dup2 stdout: %s", strerror(errno));
734 if (dup2(ttyfd, 2) < 0)
735 error("dup2 stderr: %s", strerror(errno));
737 /* Close the extra descriptor for the pseudo tty. */
740 /* record login, etc. similar to login(1) */
742 if (!(options.use_login && command == NULL)) {
744 cray_init_job(s->pw); /* set up cray jid and tmpdir */
746 do_login(s, command);
748 # ifdef LOGIN_NEEDS_UTMPX
754 * Do common processing for the child, such as execing
757 do_child(s, command);
764 signal(WJSIGNAL, cray_job_termination_handler);
767 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
772 /* Parent. Close the slave side of the pseudo tty. */
775 /* Enter interactive session. */
776 s->ptymaster = ptymaster;
777 packet_set_interactive(1,
778 options.ip_qos_interactive, options.ip_qos_bulk);
780 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
782 server_loop(pid, ptyfd, fdout, -1);
783 /* server_loop _has_ closed ptyfd and fdout. */
788 #ifdef LOGIN_NEEDS_UTMPX
790 do_pre_login(Session *s)
793 struct sockaddr_storage from;
794 pid_t pid = getpid();
797 * Get IP address of client. If the connection is not a socket, let
798 * the address be 0.0.0.0.
800 memset(&from, 0, sizeof(from));
801 fromlen = sizeof(from);
802 if (packet_connection_is_on_socket()) {
803 if (getpeername(packet_get_connection_in(),
804 (struct sockaddr *)&from, &fromlen) < 0) {
805 debug("getpeername: %.100s", strerror(errno));
810 record_utmp_only(pid, s->tty, s->pw->pw_name,
811 get_remote_name_or_ip(utmp_len, options.use_dns),
812 (struct sockaddr *)&from, fromlen);
817 * This is called to fork and execute a command. If another command is
818 * to be forced, execute that instead.
821 do_exec(Session *s, const char *command)
824 const char *forced = NULL;
825 char session_type[1024], *tty = NULL;
827 if (options.adm_forced_command) {
828 original_command = command;
829 command = options.adm_forced_command;
831 } else if (forced_command) {
832 original_command = command;
833 command = forced_command;
834 forced = "(key-option)";
836 if (forced != NULL) {
837 if (IS_INTERNAL_SFTP(command)) {
838 s->is_subsystem = s->is_subsystem ?
839 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
840 } else if (s->is_subsystem)
841 s->is_subsystem = SUBSYSTEM_EXT;
842 snprintf(session_type, sizeof(session_type),
843 "forced-command %s '%.900s'", forced, command);
844 } else if (s->is_subsystem) {
845 snprintf(session_type, sizeof(session_type),
846 "subsystem '%.900s'", s->subsys);
847 } else if (command == NULL) {
848 snprintf(session_type, sizeof(session_type), "shell");
850 /* NB. we don't log unforced commands to preserve privacy */
851 snprintf(session_type, sizeof(session_type), "command");
854 if (s->ttyfd != -1) {
856 if (strncmp(tty, "/dev/", 5) == 0)
860 verbose("Starting session: %s%s%s for %s from %.200s port %d",
862 tty == NULL ? "" : " on ",
863 tty == NULL ? "" : tty,
868 #ifdef SSH_AUDIT_EVENTS
870 PRIVSEP(audit_run_command(command));
871 else if (s->ttyfd == -1) {
872 char *shell = s->pw->pw_shell;
874 if (shell[0] == '\0') /* empty shell means /bin/sh */
876 PRIVSEP(audit_run_command(shell));
880 ret = do_exec_pty(s, command);
882 ret = do_exec_no_pty(s, command);
884 original_command = NULL;
887 * Clear loginmsg: it's the child's responsibility to display
888 * it to the user, otherwise multiple sessions may accumulate
889 * multiple copies of the login messages.
891 buffer_clear(&loginmsg);
896 /* administrative, login(1)-like work */
898 do_login(Session *s, const char *command)
901 struct sockaddr_storage from;
902 struct passwd * pw = s->pw;
903 pid_t pid = getpid();
906 * Get IP address of client. If the connection is not a socket, let
907 * the address be 0.0.0.0.
909 memset(&from, 0, sizeof(from));
910 fromlen = sizeof(from);
911 if (packet_connection_is_on_socket()) {
912 if (getpeername(packet_get_connection_in(),
913 (struct sockaddr *)&from, &fromlen) < 0) {
914 debug("getpeername: %.100s", strerror(errno));
919 /* Record that there was a login on that tty from the remote host. */
921 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
922 get_remote_name_or_ip(utmp_len,
924 (struct sockaddr *)&from, fromlen);
928 * If password change is needed, do it now.
929 * This needs to occur before the ~/.hushlogin check.
931 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
934 s->authctxt->force_pwchange = 0;
935 /* XXX - signal [net] parent to enable forwardings */
939 if (check_quietlogin(s, command))
948 * Display the message of the day.
956 if (options.print_motd) {
957 #ifdef HAVE_LOGIN_CAP
958 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
961 f = fopen("/etc/motd", "r");
964 while (fgets(buf, sizeof(buf), f))
973 * Check for quiet login, either .hushlogin or command given.
976 check_quietlogin(Session *s, const char *command)
979 struct passwd *pw = s->pw;
982 /* Return 1 if .hushlogin exists or a command given. */
985 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
986 #ifdef HAVE_LOGIN_CAP
987 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
990 if (stat(buf, &st) >= 0)
997 * Sets the value of the given variable in the environment. If the variable
998 * already exists, its value is overridden.
1001 child_set_env(char ***envp, u_int *envsizep, const char *name,
1008 if (strchr(name, '=') != NULL) {
1009 error("Invalid environment variable \"%.100s\"", name);
1014 * If we're passed an uninitialized list, allocate a single null
1015 * entry before continuing.
1017 if (*envp == NULL && *envsizep == 0) {
1018 *envp = xmalloc(sizeof(char *));
1024 * Find the slot where the value should be stored. If the variable
1025 * already exists, we reuse the slot; otherwise we append a new slot
1026 * at the end of the array, expanding if necessary.
1029 namelen = strlen(name);
1030 for (i = 0; env[i]; i++)
1031 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1034 /* Reuse the slot. */
1037 /* New variable. Expand if necessary. */
1038 envsize = *envsizep;
1039 if (i >= envsize - 1) {
1040 if (envsize >= 1000)
1041 fatal("child_set_env: too many env vars");
1043 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1044 *envsizep = envsize;
1046 /* Need to set the NULL pointer at end of array beyond the new slot. */
1050 /* Allocate space and format the variable in the appropriate slot. */
1051 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1052 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1056 * Reads environment variables from the given file and adds/overrides them
1057 * into the environment. If the file does not exist, this does nothing.
1058 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1059 * and assignments of the form name=value. No other forms are allowed.
1062 read_environment_file(char ***env, u_int *envsize,
1063 const char *filename)
1070 f = fopen(filename, "r");
1074 while (fgets(buf, sizeof(buf), f)) {
1075 if (++lineno > 1000)
1076 fatal("Too many lines in environment file %s", filename);
1077 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1079 if (!*cp || *cp == '#' || *cp == '\n')
1082 cp[strcspn(cp, "\n")] = '\0';
1084 value = strchr(cp, '=');
1085 if (value == NULL) {
1086 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1091 * Replace the equals sign by nul, and advance value to
1096 child_set_env(env, envsize, cp, value);
1101 #ifdef HAVE_ETC_DEFAULT_LOGIN
1103 * Return named variable from specified environment, or NULL if not present.
1106 child_get_env(char **env, const char *name)
1112 for (i=0; env[i] != NULL; i++)
1113 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1114 return(env[i] + len + 1);
1119 * Read /etc/default/login.
1120 * We pick up the PATH (or SUPATH for root) and UMASK.
1123 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1125 char **tmpenv = NULL, *var;
1126 u_int i, tmpenvsize = 0;
1130 * We don't want to copy the whole file to the child's environment,
1131 * so we use a temporary environment and copy the variables we're
1134 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1140 var = child_get_env(tmpenv, "SUPATH");
1142 var = child_get_env(tmpenv, "PATH");
1144 child_set_env(env, envsize, "PATH", var);
1146 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1147 if (sscanf(var, "%5lo", &mask) == 1)
1148 umask((mode_t)mask);
1150 for (i = 0; tmpenv[i] != NULL; i++)
1154 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1157 copy_environment(char **source, char ***env, u_int *envsize)
1159 char *var_name, *var_val;
1165 for(i = 0; source[i] != NULL; i++) {
1166 var_name = xstrdup(source[i]);
1167 if ((var_val = strstr(var_name, "=")) == NULL) {
1173 debug3("Copy environment: %s=%s", var_name, var_val);
1174 child_set_env(env, envsize, var_name, var_val);
1181 do_setup_env(Session *s, const char *shell)
1186 struct passwd *pw = s->pw;
1187 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1190 extern char **environ;
1194 /* Initialize the environment. */
1196 env = xcalloc(envsize, sizeof(char *));
1201 * The Windows environment contains some setting which are
1202 * important for a running system. They must not be dropped.
1207 p = fetch_windows_environment();
1208 copy_environment(p, &env, &envsize);
1209 free_windows_environment(p);
1214 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1217 /* Allow any GSSAPI methods that we've used to alter
1218 * the childs environment as they see fit
1220 ssh_gssapi_do_child(&env, &envsize);
1223 if (!options.use_login) {
1224 /* Set basic environment. */
1225 for (i = 0; i < s->num_env; i++)
1226 child_set_env(&env, &envsize, s->env[i].name,
1229 child_set_env(&env, &envsize, "USER", pw->pw_name);
1230 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1232 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1234 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1235 snprintf(buf, sizeof buf, "%.200s/%.50s",
1236 _PATH_MAILDIR, pw->pw_name);
1237 child_set_env(&env, &envsize, "MAIL", buf);
1238 #ifdef HAVE_LOGIN_CAP
1239 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1240 child_set_env(&env, &envsize, "TERM", "su");
1242 environ = xmalloc(sizeof(char *));
1244 (void) setusercontext(lc, pw, pw->pw_uid,
1245 LOGIN_SETENV|LOGIN_SETPATH);
1246 copy_environment(environ, &env, &envsize);
1247 for (var = environ; *var != NULL; ++var)
1251 #else /* HAVE_LOGIN_CAP */
1252 # ifndef HAVE_CYGWIN
1254 * There's no standard path on Windows. The path contains
1255 * important components pointing to the system directories,
1256 * needed for loading shared libraries. So the path better
1257 * remains intact here.
1259 # ifdef HAVE_ETC_DEFAULT_LOGIN
1260 read_etc_default_login(&env, &envsize, pw->pw_uid);
1261 path = child_get_env(env, "PATH");
1262 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1263 if (path == NULL || *path == '\0') {
1264 child_set_env(&env, &envsize, "PATH",
1265 s->pw->pw_uid == 0 ?
1266 SUPERUSER_PATH : _PATH_STDPATH);
1268 # endif /* HAVE_CYGWIN */
1269 #endif /* HAVE_LOGIN_CAP */
1271 /* Normal systems set SHELL by default. */
1272 child_set_env(&env, &envsize, "SHELL", shell);
1275 /* Set custom environment options from RSA authentication. */
1276 if (!options.use_login) {
1277 while (custom_environment) {
1278 struct envstring *ce = custom_environment;
1281 for (i = 0; str[i] != '=' && str[i]; i++)
1283 if (str[i] == '=') {
1285 child_set_env(&env, &envsize, str, str + i + 1);
1287 custom_environment = ce->next;
1293 /* SSH_CLIENT deprecated */
1294 snprintf(buf, sizeof buf, "%.50s %d %d",
1295 get_remote_ipaddr(), get_remote_port(), get_local_port());
1296 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1298 laddr = get_local_ipaddr(packet_get_connection_in());
1299 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1300 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1302 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1305 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1307 child_set_env(&env, &envsize, "TERM", s->term);
1309 child_set_env(&env, &envsize, "DISPLAY", s->display);
1310 if (original_command)
1311 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1315 if (cray_tmpdir[0] != '\0')
1316 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1317 #endif /* _UNICOS */
1320 * Since we clear KRB5CCNAME at startup, if it's set now then it
1321 * must have been set by a native authentication method (eg AIX or
1322 * SIA), so copy it to the child.
1327 if ((cp = getenv("KRB5CCNAME")) != NULL)
1328 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1335 if ((cp = getenv("AUTHSTATE")) != NULL)
1336 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1337 read_environment_file(&env, &envsize, "/etc/environment");
1341 if (s->authctxt->krb5_ccname)
1342 child_set_env(&env, &envsize, "KRB5CCNAME",
1343 s->authctxt->krb5_ccname);
1347 * Pull in any environment variables that may have
1350 if (options.use_pam) {
1353 p = fetch_pam_child_environment();
1354 copy_environment(p, &env, &envsize);
1355 free_pam_environment(p);
1357 p = fetch_pam_environment();
1358 copy_environment(p, &env, &envsize);
1359 free_pam_environment(p);
1361 #endif /* USE_PAM */
1363 if (auth_sock_name != NULL)
1364 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1367 /* read $HOME/.ssh/environment. */
1368 if (options.permit_user_env && !options.use_login) {
1369 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1370 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1371 read_environment_file(&env, &envsize, buf);
1374 /* dump the environment */
1375 fprintf(stderr, "Environment:\n");
1376 for (i = 0; env[i]; i++)
1377 fprintf(stderr, " %.200s\n", env[i]);
1383 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1384 * first in this order).
1387 do_rc_files(Session *s, const char *shell)
1395 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1397 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1398 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1399 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1400 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1401 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1403 fprintf(stderr, "Running %s\n", cmd);
1404 f = popen(cmd, "w");
1407 fprintf(f, "%s %s\n", s->auth_proto,
1411 fprintf(stderr, "Could not run %s\n",
1413 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1415 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1416 _PATH_SSH_SYSTEM_RC);
1417 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1420 fprintf(f, "%s %s\n", s->auth_proto,
1424 fprintf(stderr, "Could not run %s\n",
1425 _PATH_SSH_SYSTEM_RC);
1426 } else if (do_xauth && options.xauth_location != NULL) {
1427 /* Add authority data to .Xauthority if appropriate. */
1430 "Running %.500s remove %.100s\n",
1431 options.xauth_location, s->auth_display);
1433 "%.500s add %.100s %.100s %.100s\n",
1434 options.xauth_location, s->auth_display,
1435 s->auth_proto, s->auth_data);
1437 snprintf(cmd, sizeof cmd, "%s -q -",
1438 options.xauth_location);
1439 f = popen(cmd, "w");
1441 fprintf(f, "remove %s\n",
1443 fprintf(f, "add %s %s %s\n",
1444 s->auth_display, s->auth_proto,
1448 fprintf(stderr, "Could not run %s\n",
1455 do_nologin(struct passwd *pw)
1458 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1461 #ifdef HAVE_LOGIN_CAP
1462 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1464 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1466 if (pw->pw_uid == 0)
1470 if (stat(nl, &sb) == -1) {
1476 /* /etc/nologin exists. Print its contents if we can and exit. */
1477 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1478 if ((f = fopen(nl, "r")) != NULL) {
1479 while (fgets(buf, sizeof(buf), f))
1487 * Chroot into a directory after checking it for safety: all path components
1488 * must be root-owned directories with strict permissions.
1491 safely_chroot(const char *path, uid_t uid)
1494 char component[MAXPATHLEN];
1498 fatal("chroot path does not begin at root");
1499 if (strlen(path) >= sizeof(component))
1500 fatal("chroot path too long");
1503 * Descend the path, checking that each component is a
1504 * root-owned directory with strict permissions.
1506 for (cp = path; cp != NULL;) {
1507 if ((cp = strchr(cp, '/')) == NULL)
1508 strlcpy(component, path, sizeof(component));
1511 memcpy(component, path, cp - path);
1512 component[cp - path] = '\0';
1515 debug3("%s: checking '%s'", __func__, component);
1517 if (stat(component, &st) != 0)
1518 fatal("%s: stat(\"%s\"): %s", __func__,
1519 component, strerror(errno));
1520 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1521 fatal("bad ownership or modes for chroot "
1522 "directory %s\"%s\"",
1523 cp == NULL ? "" : "component ", component);
1524 if (!S_ISDIR(st.st_mode))
1525 fatal("chroot path %s\"%s\" is not a directory",
1526 cp == NULL ? "" : "component ", component);
1530 if (chdir(path) == -1)
1531 fatal("Unable to chdir to chroot path \"%s\": "
1532 "%s", path, strerror(errno));
1533 if (chroot(path) == -1)
1534 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1535 if (chdir("/") == -1)
1536 fatal("%s: chdir(/) after chroot: %s",
1537 __func__, strerror(errno));
1538 verbose("Changed root directory to \"%s\"", path);
1541 /* Set login name, uid, gid, and groups. */
1543 do_setusercontext(struct passwd *pw)
1545 char *chroot_path, *tmp;
1547 platform_setusercontext(pw);
1549 if (platform_privileged_uidswap()) {
1550 #ifdef HAVE_LOGIN_CAP
1551 if (setusercontext(lc, pw, pw->pw_uid,
1552 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1553 perror("unable to set user context");
1557 if (setlogin(pw->pw_name) < 0)
1558 error("setlogin failed: %s", strerror(errno));
1559 if (setgid(pw->pw_gid) < 0) {
1563 /* Initialize the group list. */
1564 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1565 perror("initgroups");
1571 platform_setusercontext_post_groups(pw);
1573 if (options.chroot_directory != NULL &&
1574 strcasecmp(options.chroot_directory, "none") != 0) {
1575 tmp = tilde_expand_filename(options.chroot_directory,
1577 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1578 "u", pw->pw_name, (char *)NULL);
1579 safely_chroot(chroot_path, pw->pw_uid);
1582 /* Make sure we don't attempt to chroot again */
1583 free(options.chroot_directory);
1584 options.chroot_directory = NULL;
1587 #ifdef HAVE_LOGIN_CAP
1588 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1589 perror("unable to set user context (setuser)");
1593 * FreeBSD's setusercontext() will not apply the user's
1594 * own umask setting unless running with the user's UID.
1596 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK);
1599 if (set_id(pw->pw_name) != 0) {
1600 fatal("set_id(%s) Failed", pw->pw_name);
1602 # endif /* USE_LIBIAF */
1603 /* Permanently switch to the desired uid. */
1604 permanently_set_uid(pw);
1606 } else if (options.chroot_directory != NULL &&
1607 strcasecmp(options.chroot_directory, "none") != 0) {
1608 fatal("server lacks privileges to chroot to ChrootDirectory");
1611 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1612 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1616 do_pwchange(Session *s)
1619 fprintf(stderr, "WARNING: Your password has expired.\n");
1620 if (s->ttyfd != -1) {
1622 "You must change your password now and login again!\n");
1626 #ifdef PASSWD_NEEDS_USERNAME
1627 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1630 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1635 "Password change required but no TTY available.\n");
1641 launch_login(struct passwd *pw, const char *hostname)
1643 /* Launch login(1). */
1645 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1646 #ifdef xxxLOGIN_NEEDS_TERM
1647 (s->term ? s->term : "unknown"),
1648 #endif /* LOGIN_NEEDS_TERM */
1649 #ifdef LOGIN_NO_ENDOPT
1650 "-p", "-f", pw->pw_name, (char *)NULL);
1652 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1655 /* Login couldn't be executed, die. */
1662 child_close_fds(void)
1664 extern AuthenticationConnection *auth_conn;
1667 ssh_close_authentication_connection(auth_conn);
1671 if (packet_get_connection_in() == packet_get_connection_out())
1672 close(packet_get_connection_in());
1674 close(packet_get_connection_in());
1675 close(packet_get_connection_out());
1678 * Close all descriptors related to channels. They will still remain
1679 * open in the parent.
1681 /* XXX better use close-on-exec? -markus */
1682 channel_close_all();
1685 * Close any extra file descriptors. Note that there may still be
1686 * descriptors left by system functions. They will be closed later.
1691 * Close any extra open file descriptors so that we don't have them
1692 * hanging around in clients. Note that we want to do this after
1693 * initgroups, because at least on Solaris 2.3 it leaves file
1696 closefrom(STDERR_FILENO + 1);
1700 * Performs common processing for the child, such as setting up the
1701 * environment, closing extra file descriptors, setting the user and group
1702 * ids, and executing the command or shell.
1706 do_child(Session *s, const char *command)
1708 extern char **environ;
1710 char *argv[ARGV_MAX];
1711 const char *shell, *shell0, *hostname = NULL;
1712 struct passwd *pw = s->pw;
1715 /* remove hostkey from the child's memory */
1716 destroy_sensitive_data();
1718 /* Force a password change */
1719 if (s->authctxt->force_pwchange) {
1720 do_setusercontext(pw);
1726 /* login(1) is only called if we execute the login shell */
1727 if (options.use_login && command != NULL)
1728 options.use_login = 0;
1731 cray_setup(pw->pw_uid, pw->pw_name, command);
1732 #endif /* _UNICOS */
1735 * Login(1) does this as well, and it needs uid 0 for the "-h"
1736 * switch, so we let login(1) to this for us.
1738 if (!options.use_login) {
1740 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1741 if (!check_quietlogin(s, command))
1743 #else /* HAVE_OSF_SIA */
1744 /* When PAM is enabled we rely on it to do the nologin check */
1745 if (!options.use_pam)
1747 do_setusercontext(pw);
1749 * PAM session modules in do_setusercontext may have
1750 * generated messages, so if this in an interactive
1751 * login then display them too.
1753 if (!check_quietlogin(s, command))
1755 #endif /* HAVE_OSF_SIA */
1759 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1760 debug3("PAM session not opened, exiting");
1767 * Get the shell from the password data. An empty shell field is
1768 * legal, and means /bin/sh.
1770 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1773 * Make sure $SHELL points to the shell from the password file,
1774 * even if shell is overridden from login.conf
1776 env = do_setup_env(s, shell);
1778 #ifdef HAVE_LOGIN_CAP
1779 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1782 /* we have to stash the hostname before we close our socket. */
1783 if (options.use_login)
1784 hostname = get_remote_name_or_ip(utmp_len,
1787 * Close the connection descriptors; note that this is the child, and
1788 * the server will still have the socket open, and it is important
1789 * that we do not shutdown it. Note that the descriptors cannot be
1790 * closed before building the environment, as we call
1791 * get_remote_ipaddr there.
1796 * Must take new environment into use so that .ssh/rc,
1797 * /etc/ssh/sshrc and xauth are run in the proper environment.
1801 #if defined(KRB5) && defined(USE_AFS)
1803 * At this point, we check to see if AFS is active and if we have
1804 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1805 * if we can (and need to) extend the ticket into an AFS token. If
1806 * we don't do this, we run into potential problems if the user's
1807 * home directory is in AFS and it's not world-readable.
1810 if (options.kerberos_get_afs_token && k_hasafs() &&
1811 (s->authctxt->krb5_ctx != NULL)) {
1814 debug("Getting AFS token");
1818 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1819 krb5_afslog(s->authctxt->krb5_ctx,
1820 s->authctxt->krb5_fwd_ccache, cell, NULL);
1822 krb5_afslog_home(s->authctxt->krb5_ctx,
1823 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1827 /* Change current directory to the user's home directory. */
1828 if (chdir(pw->pw_dir) < 0) {
1829 /* Suppress missing homedir warning for chroot case */
1830 #ifdef HAVE_LOGIN_CAP
1831 r = login_getcapbool(lc, "requirehome", 0);
1833 if (r || options.chroot_directory == NULL ||
1834 strcasecmp(options.chroot_directory, "none") == 0)
1835 fprintf(stderr, "Could not chdir to home "
1836 "directory %s: %s\n", pw->pw_dir,
1842 closefrom(STDERR_FILENO + 1);
1844 if (!options.use_login)
1845 do_rc_files(s, shell);
1847 /* restore SIGPIPE for child */
1848 signal(SIGPIPE, SIG_DFL);
1850 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1851 printf("This service allows sftp connections only.\n");
1854 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1855 extern int optind, optreset;
1859 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1860 args = xstrdup(command ? command : "sftp-server");
1861 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1862 if (i < ARGV_MAX - 1)
1865 optind = optreset = 1;
1866 __progname = argv[0];
1868 ssh_selinux_change_context("sftpd_t");
1870 exit(sftp_server_main(i, argv, s->pw));
1875 if (options.use_login) {
1876 launch_login(pw, hostname);
1880 /* Get the last component of the shell name. */
1881 if ((shell0 = strrchr(shell, '/')) != NULL)
1887 * If we have no command, execute the shell. In this case, the shell
1888 * name to be passed in argv[0] is preceded by '-' to indicate that
1889 * this is a login shell.
1894 /* Start the shell. Set initial character to '-'. */
1897 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1898 >= sizeof(argv0) - 1) {
1904 /* Execute the shell. */
1907 execve(shell, argv, env);
1909 /* Executing the shell failed. */
1914 * Execute the command using the user's shell. This uses the -c
1915 * option to execute the command.
1917 argv[0] = (char *) shell0;
1919 argv[2] = (char *) command;
1921 execve(shell, argv, env);
1927 session_unused(int id)
1929 debug3("%s: session id %d unused", __func__, id);
1930 if (id >= options.max_sessions ||
1931 id >= sessions_nalloc) {
1932 fatal("%s: insane session id %d (max %d nalloc %d)",
1933 __func__, id, options.max_sessions, sessions_nalloc);
1935 memset(&sessions[id], 0, sizeof(*sessions));
1936 sessions[id].self = id;
1937 sessions[id].used = 0;
1938 sessions[id].chanid = -1;
1939 sessions[id].ptyfd = -1;
1940 sessions[id].ttyfd = -1;
1941 sessions[id].ptymaster = -1;
1942 sessions[id].x11_chanids = NULL;
1943 sessions[id].next_unused = sessions_first_unused;
1944 sessions_first_unused = id;
1952 if (sessions_first_unused == -1) {
1953 if (sessions_nalloc >= options.max_sessions)
1955 debug2("%s: allocate (allocated %d max %d)",
1956 __func__, sessions_nalloc, options.max_sessions);
1957 tmp = xrealloc(sessions, sessions_nalloc + 1,
1960 error("%s: cannot allocate %d sessions",
1961 __func__, sessions_nalloc + 1);
1965 session_unused(sessions_nalloc++);
1968 if (sessions_first_unused >= sessions_nalloc ||
1969 sessions_first_unused < 0) {
1970 fatal("%s: insane first_unused %d max %d nalloc %d",
1971 __func__, sessions_first_unused, options.max_sessions,
1975 s = &sessions[sessions_first_unused];
1977 fatal("%s: session %d already used",
1978 __func__, sessions_first_unused);
1980 sessions_first_unused = s->next_unused;
1982 s->next_unused = -1;
1983 debug("session_new: session %d", s->self);
1992 for (i = 0; i < sessions_nalloc; i++) {
1993 Session *s = &sessions[i];
1995 debug("dump: used %d next_unused %d session %d %p "
1996 "channel %d pid %ld",
2007 session_open(Authctxt *authctxt, int chanid)
2009 Session *s = session_new();
2010 debug("session_open: channel %d", chanid);
2012 error("no more sessions");
2015 s->authctxt = authctxt;
2016 s->pw = authctxt->pw;
2017 if (s->pw == NULL || !authctxt->valid)
2018 fatal("no user for session %d", s->self);
2019 debug("session_open: session %d: link with channel %d", s->self, chanid);
2025 session_by_tty(char *tty)
2028 for (i = 0; i < sessions_nalloc; i++) {
2029 Session *s = &sessions[i];
2030 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2031 debug("session_by_tty: session %d tty %s", i, tty);
2035 debug("session_by_tty: unknown tty %.100s", tty);
2041 session_by_channel(int id)
2044 for (i = 0; i < sessions_nalloc; i++) {
2045 Session *s = &sessions[i];
2046 if (s->used && s->chanid == id) {
2047 debug("session_by_channel: session %d channel %d",
2052 debug("session_by_channel: unknown channel %d", id);
2058 session_by_x11_channel(int id)
2062 for (i = 0; i < sessions_nalloc; i++) {
2063 Session *s = &sessions[i];
2065 if (s->x11_chanids == NULL || !s->used)
2067 for (j = 0; s->x11_chanids[j] != -1; j++) {
2068 if (s->x11_chanids[j] == id) {
2069 debug("session_by_x11_channel: session %d "
2070 "channel %d", s->self, id);
2075 debug("session_by_x11_channel: unknown channel %d", id);
2081 session_by_pid(pid_t pid)
2084 debug("session_by_pid: pid %ld", (long)pid);
2085 for (i = 0; i < sessions_nalloc; i++) {
2086 Session *s = &sessions[i];
2087 if (s->used && s->pid == pid)
2090 error("session_by_pid: unknown pid %ld", (long)pid);
2096 session_window_change_req(Session *s)
2098 s->col = packet_get_int();
2099 s->row = packet_get_int();
2100 s->xpixel = packet_get_int();
2101 s->ypixel = packet_get_int();
2103 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2108 session_pty_req(Session *s)
2113 if (no_pty_flag || !options.permit_tty) {
2114 debug("Allocating a pty not permitted for this authentication.");
2117 if (s->ttyfd != -1) {
2118 packet_disconnect("Protocol error: you already have a pty.");
2122 s->term = packet_get_string(&len);
2125 s->col = packet_get_int();
2126 s->row = packet_get_int();
2128 s->row = packet_get_int();
2129 s->col = packet_get_int();
2131 s->xpixel = packet_get_int();
2132 s->ypixel = packet_get_int();
2134 if (strcmp(s->term, "") == 0) {
2139 /* Allocate a pty and open it. */
2140 debug("Allocating pty.");
2141 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2147 error("session_pty_req: session %d alloc failed", s->self);
2150 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2152 /* for SSH1 the tty modes length is not given */
2154 n_bytes = packet_remaining();
2155 tty_parse_modes(s->ttyfd, &n_bytes);
2158 pty_setowner(s->pw, s->tty);
2160 /* Set window size from the packet. */
2161 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2164 session_proctitle(s);
2169 session_subsystem_req(Session *s)
2177 s->subsys = packet_get_string(&len);
2179 debug2("subsystem request for %.100s by user %s", s->subsys,
2182 for (i = 0; i < options.num_subsystems; i++) {
2183 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
2184 prog = options.subsystem_command[i];
2185 cmd = options.subsystem_args[i];
2186 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2187 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2188 debug("subsystem: %s", prog);
2190 if (stat(prog, &st) < 0)
2191 debug("subsystem: cannot stat %s: %s",
2192 prog, strerror(errno));
2193 s->is_subsystem = SUBSYSTEM_EXT;
2194 debug("subsystem: exec() %s", cmd);
2196 success = do_exec(s, cmd) == 0;
2202 logit("subsystem request for %.100s by user %s failed, "
2203 "subsystem not found", s->subsys, s->pw->pw_name);
2209 session_x11_req(Session *s)
2213 if (s->auth_proto != NULL || s->auth_data != NULL) {
2214 error("session_x11_req: session %d: "
2215 "x11 forwarding already active", s->self);
2218 s->single_connection = packet_get_char();
2219 s->auth_proto = packet_get_string(NULL);
2220 s->auth_data = packet_get_string(NULL);
2221 s->screen = packet_get_int();
2224 if (xauth_valid_string(s->auth_proto) &&
2225 xauth_valid_string(s->auth_data))
2226 success = session_setup_x11fwd(s);
2229 error("Invalid X11 forwarding data");
2232 free(s->auth_proto);
2234 s->auth_proto = NULL;
2235 s->auth_data = NULL;
2241 session_shell_req(Session *s)
2244 return do_exec(s, NULL) == 0;
2248 session_exec_req(Session *s)
2252 char *command = packet_get_string(&len);
2254 success = do_exec(s, command) == 0;
2260 session_break_req(Session *s)
2263 packet_get_int(); /* ignored */
2266 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2272 session_env_req(Session *s)
2275 u_int name_len, val_len, i;
2277 name = packet_get_cstring(&name_len);
2278 val = packet_get_cstring(&val_len);
2281 /* Don't set too many environment variables */
2282 if (s->num_env > 128) {
2283 debug2("Ignoring env request %s: too many env vars", name);
2287 for (i = 0; i < options.num_accept_env; i++) {
2288 if (match_pattern(name, options.accept_env[i])) {
2289 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2290 s->env = xrealloc(s->env, s->num_env + 1,
2292 s->env[s->num_env].name = name;
2293 s->env[s->num_env].val = val;
2298 debug2("Ignoring env request %s: disallowed name", name);
2307 session_auth_agent_req(Session *s)
2309 static int called = 0;
2311 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2312 debug("session_auth_agent_req: no_agent_forwarding_flag");
2319 return auth_input_request_forwarding(s->pw);
2324 session_input_channel_req(Channel *c, const char *rtype)
2329 if ((s = session_by_channel(c->self)) == NULL) {
2330 logit("session_input_channel_req: no session %d req %.100s",
2334 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2337 * a session is in LARVAL state until a shell, a command
2338 * or a subsystem is executed
2340 if (c->type == SSH_CHANNEL_LARVAL) {
2341 if (strcmp(rtype, "shell") == 0) {
2342 success = session_shell_req(s);
2343 } else if (strcmp(rtype, "exec") == 0) {
2344 success = session_exec_req(s);
2345 } else if (strcmp(rtype, "pty-req") == 0) {
2346 success = session_pty_req(s);
2347 } else if (strcmp(rtype, "x11-req") == 0) {
2348 success = session_x11_req(s);
2349 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2350 success = session_auth_agent_req(s);
2351 } else if (strcmp(rtype, "subsystem") == 0) {
2352 success = session_subsystem_req(s);
2353 } else if (strcmp(rtype, "env") == 0) {
2354 success = session_env_req(s);
2357 if (strcmp(rtype, "window-change") == 0) {
2358 success = session_window_change_req(s);
2359 } else if (strcmp(rtype, "break") == 0) {
2360 success = session_break_req(s);
2367 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2371 fatal("session_set_fds: called for proto != 2.0");
2373 * now that have a child and a pipe to the child,
2374 * we can activate our channel and register the fd's
2376 if (s->chanid == -1)
2377 fatal("no channel for session %d", s->self);
2378 if (options.hpn_disabled)
2379 channel_set_fds(s->chanid, fdout, fdin, fderr,
2380 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2381 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2383 channel_set_fds(s->chanid, fdout, fdin, fderr,
2384 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2385 1, is_tty, options.hpn_buffer_size);
2389 * Function to perform pty cleanup. Also called if we get aborted abnormally
2390 * (e.g., due to a dropped connection).
2393 session_pty_cleanup2(Session *s)
2396 error("session_pty_cleanup: no session");
2402 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2404 /* Record that the user has logged out. */
2406 record_logout(s->pid, s->tty, s->pw->pw_name);
2408 /* Release the pseudo-tty. */
2410 pty_release(s->tty);
2413 * Close the server side of the socket pairs. We must do this after
2414 * the pty cleanup, so that another process doesn't get this pty
2415 * while we're still cleaning up.
2417 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2418 error("close(s->ptymaster/%d): %s",
2419 s->ptymaster, strerror(errno));
2421 /* unlink pty from session */
2426 session_pty_cleanup(Session *s)
2428 PRIVSEP(session_pty_cleanup2(s));
2434 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2449 return "SIG@openssh.com";
2453 session_close_x11(int id)
2457 if ((c = channel_by_id(id)) == NULL) {
2458 debug("session_close_x11: x11 channel %d missing", id);
2460 /* Detach X11 listener */
2461 debug("session_close_x11: detach x11 channel %d", id);
2462 channel_cancel_cleanup(id);
2463 if (c->ostate != CHAN_OUTPUT_CLOSED)
2469 session_close_single_x11(int id, void *arg)
2474 debug3("session_close_single_x11: channel %d", id);
2475 channel_cancel_cleanup(id);
2476 if ((s = session_by_x11_channel(id)) == NULL)
2477 fatal("session_close_single_x11: no x11 channel %d", id);
2478 for (i = 0; s->x11_chanids[i] != -1; i++) {
2479 debug("session_close_single_x11: session %d: "
2480 "closing channel %d", s->self, s->x11_chanids[i]);
2482 * The channel "id" is already closing, but make sure we
2483 * close all of its siblings.
2485 if (s->x11_chanids[i] != id)
2486 session_close_x11(s->x11_chanids[i]);
2488 free(s->x11_chanids);
2489 s->x11_chanids = NULL;
2492 free(s->auth_proto);
2493 s->auth_proto = NULL;
2495 s->auth_data = NULL;
2496 free(s->auth_display);
2497 s->auth_display = NULL;
2501 session_exit_message(Session *s, int status)
2505 if ((c = channel_lookup(s->chanid)) == NULL)
2506 fatal("session_exit_message: session %d: no channel %d",
2507 s->self, s->chanid);
2508 debug("session_exit_message: session %d channel %d pid %ld",
2509 s->self, s->chanid, (long)s->pid);
2511 if (WIFEXITED(status)) {
2512 channel_request_start(s->chanid, "exit-status", 0);
2513 packet_put_int(WEXITSTATUS(status));
2515 } else if (WIFSIGNALED(status)) {
2516 channel_request_start(s->chanid, "exit-signal", 0);
2517 packet_put_cstring(sig2name(WTERMSIG(status)));
2519 packet_put_char(WCOREDUMP(status)? 1 : 0);
2520 #else /* WCOREDUMP */
2522 #endif /* WCOREDUMP */
2523 packet_put_cstring("");
2524 packet_put_cstring("");
2527 /* Some weird exit cause. Just exit. */
2528 packet_disconnect("wait returned status %04x.", status);
2531 /* disconnect channel */
2532 debug("session_exit_message: release channel %d", s->chanid);
2535 * Adjust cleanup callback attachment to send close messages when
2536 * the channel gets EOF. The session will be then be closed
2537 * by session_close_by_channel when the childs close their fds.
2539 channel_register_cleanup(c->self, session_close_by_channel, 1);
2542 * emulate a write failure with 'chan_write_failed', nobody will be
2543 * interested in data we write.
2544 * Note that we must not call 'chan_read_failed', since there could
2545 * be some more data waiting in the pipe.
2547 if (c->ostate != CHAN_OUTPUT_CLOSED)
2548 chan_write_failed(c);
2552 session_close(Session *s)
2556 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2558 session_pty_cleanup(s);
2561 free(s->x11_chanids);
2562 free(s->auth_display);
2564 free(s->auth_proto);
2566 if (s->env != NULL) {
2567 for (i = 0; i < s->num_env; i++) {
2568 free(s->env[i].name);
2569 free(s->env[i].val);
2573 session_proctitle(s);
2574 session_unused(s->self);
2578 session_close_by_pid(pid_t pid, int status)
2580 Session *s = session_by_pid(pid);
2582 debug("session_close_by_pid: no session for pid %ld",
2586 if (s->chanid != -1)
2587 session_exit_message(s, status);
2589 session_pty_cleanup(s);
2594 * this is called when a channel dies before
2595 * the session 'child' itself dies
2598 session_close_by_channel(int id, void *arg)
2600 Session *s = session_by_channel(id);
2604 debug("session_close_by_channel: no session for id %d", id);
2607 debug("session_close_by_channel: channel %d child %ld",
2610 debug("session_close_by_channel: channel %d: has child", id);
2612 * delay detach of session, but release pty, since
2613 * the fd's to the child are already closed
2616 session_pty_cleanup(s);
2619 /* detach by removing callback */
2620 channel_cancel_cleanup(s->chanid);
2622 /* Close any X11 listeners associated with this session */
2623 if (s->x11_chanids != NULL) {
2624 for (i = 0; s->x11_chanids[i] != -1; i++) {
2625 session_close_x11(s->x11_chanids[i]);
2626 s->x11_chanids[i] = -1;
2635 session_destroy_all(void (*closefunc)(Session *))
2638 for (i = 0; i < sessions_nalloc; i++) {
2639 Session *s = &sessions[i];
2641 if (closefunc != NULL)
2650 session_tty_list(void)
2652 static char buf[1024];
2657 for (i = 0; i < sessions_nalloc; i++) {
2658 Session *s = &sessions[i];
2659 if (s->used && s->ttyfd != -1) {
2661 if (strncmp(s->tty, "/dev/", 5) != 0) {
2662 cp = strrchr(s->tty, '/');
2663 cp = (cp == NULL) ? s->tty : cp + 1;
2668 strlcat(buf, ",", sizeof buf);
2669 strlcat(buf, cp, sizeof buf);
2673 strlcpy(buf, "notty", sizeof buf);
2678 session_proctitle(Session *s)
2681 error("no user for session %d", s->self);
2683 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2687 session_setup_x11fwd(Session *s)
2690 char display[512], auth_display[512];
2691 char hostname[MAXHOSTNAMELEN];
2694 if (no_x11_forwarding_flag) {
2695 packet_send_debug("X11 forwarding disabled in user configuration file.");
2698 if (!options.x11_forwarding) {
2699 debug("X11 forwarding disabled in server configuration file.");
2702 if (!options.xauth_location ||
2703 (stat(options.xauth_location, &st) == -1)) {
2704 packet_send_debug("No xauth program; cannot forward with spoofing.");
2707 if (options.use_login) {
2708 packet_send_debug("X11 forwarding disabled; "
2709 "not compatible with UseLogin=yes.");
2712 if (s->display != NULL) {
2713 debug("X11 display already set.");
2716 if (x11_create_display_inet(options.x11_display_offset,
2717 options.x11_use_localhost, s->single_connection,
2718 &s->display_number, &s->x11_chanids) == -1) {
2719 debug("x11_create_display_inet failed.");
2722 for (i = 0; s->x11_chanids[i] != -1; i++) {
2723 channel_register_cleanup(s->x11_chanids[i],
2724 session_close_single_x11, 0);
2727 /* Set up a suitable value for the DISPLAY variable. */
2728 if (gethostname(hostname, sizeof(hostname)) < 0)
2729 fatal("gethostname: %.100s", strerror(errno));
2731 * auth_display must be used as the displayname when the
2732 * authorization entry is added with xauth(1). This will be
2733 * different than the DISPLAY string for localhost displays.
2735 if (options.x11_use_localhost) {
2736 snprintf(display, sizeof display, "localhost:%u.%u",
2737 s->display_number, s->screen);
2738 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2739 s->display_number, s->screen);
2740 s->display = xstrdup(display);
2741 s->auth_display = xstrdup(auth_display);
2743 #ifdef IPADDR_IN_DISPLAY
2745 struct in_addr my_addr;
2747 he = gethostbyname(hostname);
2749 error("Can't get IP address for X11 DISPLAY.");
2750 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2753 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2754 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2755 s->display_number, s->screen);
2757 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2758 s->display_number, s->screen);
2760 s->display = xstrdup(display);
2761 s->auth_display = xstrdup(display);
2768 do_authenticated2(Authctxt *authctxt)
2770 server_loop2(authctxt);
2774 do_cleanup(Authctxt *authctxt)
2776 static int called = 0;
2778 debug("do_cleanup");
2780 /* no cleanup if we're in the child for login shell */
2784 /* avoid double cleanup */
2789 if (authctxt == NULL)
2793 if (options.use_pam) {
2795 sshpam_thread_cleanup();
2799 if (!authctxt->authenticated)
2803 if (options.kerberos_ticket_cleanup &&
2805 krb5_cleanup_proc(authctxt);
2809 if (compat20 && options.gss_cleanup_creds)
2810 ssh_gssapi_cleanup_creds();
2813 /* remove agent socket */
2814 auth_sock_cleanup_proc(authctxt->pw);
2817 * Cleanup ptys/utmp only if privsep is disabled,
2818 * or if running in monitor.
2820 if (!use_privsep || mm_is_monitor())
2821 session_destroy_all(session_pty_cleanup2);