1 /* $OpenBSD: session.c,v 1.241 2008/06/16 13:22:53 dtucker Exp $ */
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 #include <sys/types.h>
39 #include <sys/param.h>
40 #ifdef HAVE_SYS_STAT_H
41 # include <sys/stat.h>
43 #include <sys/socket.h>
47 #include <arpa/inet.h>
62 #include "openbsd-compat/sys-queue.h"
81 #include "auth-options.h"
82 #include "pathnames.h"
86 #include "serverloop.h"
91 #include "monitor_wrap.h"
94 #if defined(KRB5) && defined(USE_AFS)
100 Session *session_new(void);
101 void session_set_fds(Session *, int, int, int, int);
102 void session_pty_cleanup(Session *);
103 void session_proctitle(Session *);
104 int session_setup_x11fwd(Session *);
105 int do_exec_pty(Session *, const char *);
106 int do_exec_no_pty(Session *, const char *);
107 int do_exec(Session *, const char *);
108 void do_login(Session *, const char *);
109 #ifdef LOGIN_NEEDS_UTMPX
110 static void do_pre_login(Session *s);
112 void do_child(Session *, const char *);
114 int check_quietlogin(Session *, const char *);
116 static void do_authenticated1(Authctxt *);
117 static void do_authenticated2(Authctxt *);
119 static int session_pty_req(Session *);
122 static void execute_session_hook(char* prog, Authctxt *authctxt,
123 int startup, int save);
127 extern ServerOptions options;
128 extern char *__progname;
129 extern int log_stderr;
130 extern int debug_flag;
131 extern u_int utmp_len;
132 extern int startup_pipe;
133 extern void destroy_sensitive_data(void);
134 extern Buffer loginmsg;
136 /* original command from peer. */
137 const char *original_command = NULL;
140 static int sessions_first_unused = -1;
141 static int sessions_nalloc = 0;
142 static Session *sessions = NULL;
144 #define SUBSYSTEM_NONE 0
145 #define SUBSYSTEM_EXT 1
146 #define SUBSYSTEM_INT_SFTP 2
148 #ifdef HAVE_LOGIN_CAP
152 static int is_child = 0;
154 /* Name and directory of socket for authentication agent forwarding. */
155 static char *auth_sock_name = NULL;
156 static char *auth_sock_dir = NULL;
158 /* removes the agent forwarding socket */
161 auth_sock_cleanup_proc(struct passwd *pw)
163 if (auth_sock_name != NULL) {
164 temporarily_use_uid(pw);
165 unlink(auth_sock_name);
166 rmdir(auth_sock_dir);
167 auth_sock_name = NULL;
173 auth_input_request_forwarding(struct passwd * pw)
177 struct sockaddr_un sunaddr;
179 if (auth_sock_name != NULL) {
180 error("authentication forwarding requested twice.");
184 /* Temporarily drop privileged uid for mkdir/bind. */
185 temporarily_use_uid(pw);
187 /* Allocate a buffer for the socket name, and format the name. */
188 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
190 /* Create private directory for socket */
191 if (mkdtemp(auth_sock_dir) == NULL) {
192 packet_send_debug("Agent forwarding disabled: "
193 "mkdtemp() failed: %.100s", strerror(errno));
195 xfree(auth_sock_dir);
196 auth_sock_dir = NULL;
200 xasprintf(&auth_sock_name, "%s/agent.%ld",
201 auth_sock_dir, (long) getpid());
203 /* Create the socket. */
204 sock = socket(AF_UNIX, SOCK_STREAM, 0);
206 error("socket: %.100s", strerror(errno));
211 /* Bind it to the name. */
212 memset(&sunaddr, 0, sizeof(sunaddr));
213 sunaddr.sun_family = AF_UNIX;
214 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
216 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
217 error("bind: %.100s", strerror(errno));
222 /* Restore the privileged uid. */
225 /* Start listening on the socket. */
226 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
227 error("listen: %.100s", strerror(errno));
231 /* Allocate a channel for the authentication agent socket. */
232 /* this shouldn't matter if its hpn or not - cjr */
233 nc = channel_new("auth socket",
234 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
235 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
236 0, "auth socket", 1);
237 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
241 if (auth_sock_name != NULL)
242 xfree(auth_sock_name);
243 if (auth_sock_dir != NULL) {
244 rmdir(auth_sock_dir);
245 xfree(auth_sock_dir);
249 auth_sock_name = NULL;
250 auth_sock_dir = NULL;
255 display_loginmsg(void)
257 if (buffer_len(&loginmsg) > 0) {
258 buffer_append(&loginmsg, "\0", 1);
259 printf("%s", (char *)buffer_ptr(&loginmsg));
260 buffer_clear(&loginmsg);
265 do_authenticated(Authctxt *authctxt)
267 setproctitle("%s", authctxt->pw->pw_name);
269 /* setup the channel layer */
270 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
271 channel_permit_all_opens();
274 do_authenticated2(authctxt);
276 do_authenticated1(authctxt);
279 if (options.session_hooks_allow &&
280 options.session_hooks_shutdown_cmd)
282 execute_session_hook(options.session_hooks_shutdown_cmd,
284 /* startup = */ 0, /* save = */ 0);
286 if (authctxt->session_env_file)
288 free(authctxt->session_env_file);
293 do_cleanup(authctxt);
297 * Prepares for an interactive session. This is called after the user has
298 * been successfully authenticated. During this message exchange, pseudo
299 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
300 * are requested, etc.
303 do_authenticated1(Authctxt *authctxt)
307 int success, type, screen_flag;
308 int enable_compression_after_reply = 0;
309 u_int proto_len, data_len, dlen, compression_level = 0;
313 error("no more sessions");
316 s->authctxt = authctxt;
317 s->pw = authctxt->pw;
320 * We stay in this loop until the client requests to execute a shell
326 /* Get a packet from the client. */
327 type = packet_read();
329 /* Process the packet. */
331 case SSH_CMSG_REQUEST_COMPRESSION:
332 compression_level = packet_get_int();
334 if (compression_level < 1 || compression_level > 9) {
335 packet_send_debug("Received invalid compression level %d.",
339 if (options.compression == COMP_NONE) {
340 debug2("compression disabled");
343 /* Enable compression after we have responded with SUCCESS. */
344 enable_compression_after_reply = 1;
348 case SSH_CMSG_REQUEST_PTY:
349 success = session_pty_req(s);
352 case SSH_CMSG_X11_REQUEST_FORWARDING:
353 s->auth_proto = packet_get_string(&proto_len);
354 s->auth_data = packet_get_string(&data_len);
356 screen_flag = packet_get_protocol_flags() &
357 SSH_PROTOFLAG_SCREEN_NUMBER;
358 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
360 if (packet_remaining() == 4) {
362 debug2("Buggy client: "
363 "X11 screen flag missing");
364 s->screen = packet_get_int();
369 success = session_setup_x11fwd(s);
371 xfree(s->auth_proto);
373 s->auth_proto = NULL;
378 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
379 if (!options.allow_agent_forwarding ||
380 no_agent_forwarding_flag || compat13) {
381 debug("Authentication agent forwarding not permitted for this authentication.");
384 debug("Received authentication agent forwarding request.");
385 success = auth_input_request_forwarding(s->pw);
388 case SSH_CMSG_PORT_FORWARD_REQUEST:
389 if (no_port_forwarding_flag) {
390 debug("Port forwarding not permitted for this authentication.");
393 if (!options.allow_tcp_forwarding) {
394 debug("Port forwarding not permitted.");
397 debug("Received TCP/IP port forwarding request.");
398 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
399 options.gateway_ports) < 0) {
400 debug("Port forwarding failed.");
406 case SSH_CMSG_MAX_PACKET_SIZE:
407 if (packet_set_maxsize(packet_get_int()) > 0)
411 case SSH_CMSG_EXEC_SHELL:
412 case SSH_CMSG_EXEC_CMD:
413 if (type == SSH_CMSG_EXEC_CMD) {
414 command = packet_get_string(&dlen);
415 debug("Exec command '%.500s'", command);
416 if (do_exec(s, command) != 0)
418 "command execution failed");
421 if (do_exec(s, NULL) != 0)
423 "shell execution failed");
431 * Any unknown messages in this phase are ignored,
432 * and a failure message is returned.
434 logit("Unknown packet type received after authentication: %d", type);
436 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
440 /* Enable compression now that we have replied if appropriate. */
441 if (enable_compression_after_reply) {
442 enable_compression_after_reply = 0;
443 packet_start_compression(compression_level);
450 * This is called to fork and execute a command when we have no tty. This
451 * will call do_child from the child, and server_loop from the parent after
452 * setting up file descriptors and such.
455 do_exec_no_pty(Session *s, const char *command)
460 int pin[2], pout[2], perr[2];
462 /* Allocate pipes for communicating with the program. */
464 error("%s: pipe in: %.100s", __func__, strerror(errno));
467 if (pipe(pout) < 0) {
468 error("%s: pipe out: %.100s", __func__, strerror(errno));
473 if (pipe(perr) < 0) {
474 error("%s: pipe err: %.100s", __func__, strerror(errno));
482 int inout[2], err[2];
484 /* Uses socket pairs to communicate with the program. */
485 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
486 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
489 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
490 error("%s: socketpair #2: %.100s", __func__, strerror(errno));
498 fatal("do_exec_no_pty: no session");
500 session_proctitle(s);
502 /* Fork the child. */
503 switch ((pid = fork())) {
505 error("%s: fork: %.100s", __func__, strerror(errno));
523 /* Child. Reinitialize the log since the pid has changed. */
524 log_init(__progname, options.log_level,
525 options.log_facility, log_stderr);
528 * Create a new session and process group since the 4.4BSD
529 * setlogin() affects the entire process group.
532 error("setsid failed: %.100s", strerror(errno));
536 * Redirect stdin. We close the parent side of the socket
537 * pair, and make the child side the standard input.
540 if (dup2(pin[0], 0) < 0)
541 perror("dup2 stdin");
544 /* Redirect stdout. */
546 if (dup2(pout[1], 1) < 0)
547 perror("dup2 stdout");
550 /* Redirect stderr. */
552 if (dup2(perr[1], 2) < 0)
553 perror("dup2 stderr");
557 * Redirect stdin, stdout, and stderr. Stdin and stdout will
558 * use the same socket, as some programs (particularly rdist)
559 * seem to depend on it.
563 if (dup2(inout[0], 0) < 0) /* stdin */
564 perror("dup2 stdin");
565 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
566 perror("dup2 stdout");
568 if (dup2(err[0], 2) < 0) /* stderr */
569 perror("dup2 stderr");
575 cray_init_job(s->pw); /* set up cray jid and tmpdir */
578 /* Do processing for the child (exec command etc). */
579 do_child(s, command);
586 signal(WJSIGNAL, cray_job_termination_handler);
590 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
594 /* Set interactive/non-interactive mode. */
595 packet_set_interactive(s->display != NULL);
598 * Clear loginmsg, since it's the child's responsibility to display
599 * it to the user, otherwise multiple sessions may accumulate
600 * multiple copies of the login messages.
602 buffer_clear(&loginmsg);
605 /* We are the parent. Close the child sides of the pipes. */
611 if (s->is_subsystem) {
615 session_set_fds(s, pin[1], pout[0], perr[0], 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],
632 s->is_subsystem ? -1 : err[1], 0);
636 server_loop(pid, inout[1], inout[1], err[1]);
637 /* server_loop has closed inout[1] and err[1]. */
644 * This is called to fork and execute a command when we have a tty. This
645 * will call do_child from the child, and server_loop from the parent after
646 * setting up file descriptors, controlling tty, updating wtmp, utmp,
647 * lastlog, and other such operations.
650 do_exec_pty(Session *s, const char *command)
652 int fdout, ptyfd, ttyfd, ptymaster;
656 fatal("do_exec_pty: no session");
661 * Create another descriptor of the pty master side for use as the
662 * standard input. We could use the original descriptor, but this
663 * simplifies code in server_loop. The descriptor is bidirectional.
664 * Do this before forking (and cleanup in the child) so as to
665 * detect and gracefully fail out-of-fd conditions.
667 if ((fdout = dup(ptyfd)) < 0) {
668 error("%s: dup #1: %s", __func__, strerror(errno));
673 /* we keep a reference to the pty master */
674 if ((ptymaster = dup(ptyfd)) < 0) {
675 error("%s: dup #2: %s", __func__, strerror(errno));
682 /* Fork the child. */
683 switch ((pid = fork())) {
685 error("%s: fork: %.100s", __func__, strerror(errno));
697 /* Child. Reinitialize the log because the pid has changed. */
698 log_init(__progname, options.log_level,
699 options.log_facility, log_stderr);
700 /* Close the master side of the pseudo tty. */
703 /* Make the pseudo tty our controlling tty. */
704 pty_make_controlling_tty(&ttyfd, s->tty);
706 /* Redirect stdin/stdout/stderr from the pseudo tty. */
707 if (dup2(ttyfd, 0) < 0)
708 error("dup2 stdin: %s", strerror(errno));
709 if (dup2(ttyfd, 1) < 0)
710 error("dup2 stdout: %s", strerror(errno));
711 if (dup2(ttyfd, 2) < 0)
712 error("dup2 stderr: %s", strerror(errno));
714 /* Close the extra descriptor for the pseudo tty. */
717 /* record login, etc. similar to login(1) */
719 if (!(options.use_login && command == NULL)) {
721 cray_init_job(s->pw); /* set up cray jid and tmpdir */
723 do_login(s, command);
725 # ifdef LOGIN_NEEDS_UTMPX
731 * Do common processing for the child, such as execing
734 do_child(s, command);
741 signal(WJSIGNAL, cray_job_termination_handler);
745 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
750 /* Parent. Close the slave side of the pseudo tty. */
753 /* Enter interactive session. */
754 s->ptymaster = ptymaster;
755 packet_set_interactive(1);
757 session_set_fds(s, ptyfd, fdout, -1, 1);
759 server_loop(pid, ptyfd, fdout, -1);
760 /* server_loop _has_ closed ptyfd and fdout. */
765 #ifdef LOGIN_NEEDS_UTMPX
767 do_pre_login(Session *s)
770 struct sockaddr_storage from;
771 pid_t pid = getpid();
774 * Get IP address of client. If the connection is not a socket, let
775 * the address be 0.0.0.0.
777 memset(&from, 0, sizeof(from));
778 fromlen = sizeof(from);
779 if (packet_connection_is_on_socket()) {
780 if (getpeername(packet_get_connection_in(),
781 (struct sockaddr *)&from, &fromlen) < 0) {
782 debug("getpeername: %.100s", strerror(errno));
787 record_utmp_only(pid, s->tty, s->pw->pw_name,
788 get_remote_name_or_ip(utmp_len, options.use_dns),
789 (struct sockaddr *)&from, fromlen);
794 * This is called to fork and execute a command. If another command is
795 * to be forced, execute that instead.
798 do_exec(Session *s, const char *command)
802 if (options.adm_forced_command) {
803 original_command = command;
804 command = options.adm_forced_command;
805 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
806 s->is_subsystem = SUBSYSTEM_INT_SFTP;
807 else if (s->is_subsystem)
808 s->is_subsystem = SUBSYSTEM_EXT;
809 debug("Forced command (config) '%.900s'", command);
810 } else if (forced_command) {
811 original_command = command;
812 command = forced_command;
813 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
814 s->is_subsystem = SUBSYSTEM_INT_SFTP;
815 else if (s->is_subsystem)
816 s->is_subsystem = SUBSYSTEM_EXT;
817 debug("Forced command (key option) '%.900s'", command);
820 #if defined(SESSION_HOOKS)
821 if (options.session_hooks_allow &&
822 (options.session_hooks_startup_cmd ||
823 options.session_hooks_shutdown_cmd))
831 "/tmp/ssh_env_%d%d%d",
835 } while (stat(env_file, &st)==0);
836 s->authctxt->session_env_file = strdup(env_file);
840 #ifdef SSH_AUDIT_EVENTS
842 PRIVSEP(audit_run_command(command));
843 else if (s->ttyfd == -1) {
844 char *shell = s->pw->pw_shell;
846 if (shell[0] == '\0') /* empty shell means /bin/sh */
848 PRIVSEP(audit_run_command(shell));
852 ret = do_exec_pty(s, command);
854 ret = do_exec_no_pty(s, command);
856 original_command = NULL;
859 * Clear loginmsg: it's the child's responsibility to display
860 * it to the user, otherwise multiple sessions may accumulate
861 * multiple copies of the login messages.
863 buffer_clear(&loginmsg);
868 /* administrative, login(1)-like work */
870 do_login(Session *s, const char *command)
873 struct sockaddr_storage from;
874 struct passwd * pw = s->pw;
875 pid_t pid = getpid();
878 * Get IP address of client. If the connection is not a socket, let
879 * the address be 0.0.0.0.
881 memset(&from, 0, sizeof(from));
882 fromlen = sizeof(from);
883 if (packet_connection_is_on_socket()) {
884 if (getpeername(packet_get_connection_in(),
885 (struct sockaddr *) & from, &fromlen) < 0) {
886 debug("getpeername: %.100s", strerror(errno));
891 /* Record that there was a login on that tty from the remote host. */
893 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
894 get_remote_name_or_ip(utmp_len,
896 (struct sockaddr *)&from, fromlen);
900 * If password change is needed, do it now.
901 * This needs to occur before the ~/.hushlogin check.
903 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
906 s->authctxt->force_pwchange = 0;
907 /* XXX - signal [net] parent to enable forwardings */
911 if (check_quietlogin(s, command))
920 * Display the message of the day.
928 if (options.print_motd) {
929 #ifdef HAVE_LOGIN_CAP
930 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
933 f = fopen("/etc/motd", "r");
936 while (fgets(buf, sizeof(buf), f))
945 * Check for quiet login, either .hushlogin or command given.
948 check_quietlogin(Session *s, const char *command)
951 struct passwd *pw = s->pw;
954 /* Return 1 if .hushlogin exists or a command given. */
957 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
958 #ifdef HAVE_LOGIN_CAP
959 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
962 if (stat(buf, &st) >= 0)
969 * Sets the value of the given variable in the environment. If the variable
970 * already exists, its value is overriden.
973 child_set_env(char ***envp, u_int *envsizep, const char *name,
981 * If we're passed an uninitialized list, allocate a single null
982 * entry before continuing.
984 if (*envp == NULL && *envsizep == 0) {
985 *envp = xmalloc(sizeof(char *));
991 * Find the slot where the value should be stored. If the variable
992 * already exists, we reuse the slot; otherwise we append a new slot
993 * at the end of the array, expanding if necessary.
996 namelen = strlen(name);
997 for (i = 0; env[i]; i++)
998 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1001 /* Reuse the slot. */
1004 /* New variable. Expand if necessary. */
1005 envsize = *envsizep;
1006 if (i >= envsize - 1) {
1007 if (envsize >= 1000)
1008 fatal("child_set_env: too many env vars");
1010 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1011 *envsizep = envsize;
1013 /* Need to set the NULL pointer at end of array beyond the new slot. */
1017 /* Allocate space and format the variable in the appropriate slot. */
1018 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1019 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1023 * Reads environment variables from the given file and adds/overrides them
1024 * into the environment. If the file does not exist, this does nothing.
1025 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1026 * and assignments of the form name=value. No other forms are allowed.
1029 read_environment_file(char ***env, u_int *envsize,
1030 const char *filename)
1037 f = fopen(filename, "r");
1041 while (fgets(buf, sizeof(buf), f)) {
1042 if (++lineno > 1000)
1043 fatal("Too many lines in environment file %s", filename);
1044 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1046 if (!*cp || *cp == '#' || *cp == '\n')
1049 cp[strcspn(cp, "\n")] = '\0';
1051 value = strchr(cp, '=');
1052 if (value == NULL) {
1053 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1058 * Replace the equals sign by nul, and advance value to
1063 child_set_env(env, envsize, cp, value);
1068 #ifdef SESSION_HOOKS
1069 #define SSH_SESSION_ENV_FILE "SSH_SESSION_ENV_FILE"
1071 typedef enum { no_op, execute, clear_env, restore_env,
1072 read_env, save_or_rm_env } session_action_t;
1074 static session_action_t action_order[2][5] = {
1075 { clear_env, read_env, execute, save_or_rm_env, restore_env }, /*shutdown*/
1076 { execute, read_env, save_or_rm_env, no_op, no_op } /*startup */
1080 void execute_session_hook(char* prog, Authctxt *authctxt,
1081 int startup, int save)
1083 extern char **environ;
1086 char **saved_env, **tmpenv;
1087 char *env_file = authctxt->session_env_file;
1092 switch (action_order[startup][i])
1105 authctxt->pw->pw_shell,
1108 debug("executing session hook: [%s]", buf);
1109 setenv(SSH_SESSION_ENV_FILE, env_file, /* overwrite = */ 1);
1111 /* flusing is recommended in the popen(3) man page, to avoid
1112 intermingling of output */
1115 if ((fp=popen(buf, "w")) == NULL)
1117 perror("Unable to run session hook");
1120 status = pclose(fp);
1121 debug2("session hook executed, status=%d", status);
1122 unsetenv(SSH_SESSION_ENV_FILE);
1127 saved_env = environ;
1128 tmpenv = (char**) malloc(sizeof(char*));
1134 environ = saved_env;
1139 if (status==0 && stat(env_file, &st)==0)
1143 debug("reading environment from %s", env_file);
1144 while (environ[envsize++]) ;
1145 read_environment_file(&environ, &envsize, env_file);
1149 case save_or_rm_env:
1150 if (status==0 && save)
1155 debug2("saving environment to %s", env_file);
1156 if ((fp = fopen(env_file, "w")) == NULL) /* hmm: file perms? */
1158 perror("Unable to save session hook info");
1160 while (environ[envcount])
1162 fprintf(fp, "%s\n", environ[envcount++]);
1167 else if (stat(env_file, &st)==0)
1169 debug2("removing environment file %s", env_file);
1179 #ifdef HAVE_ETC_DEFAULT_LOGIN
1181 * Return named variable from specified environment, or NULL if not present.
1184 child_get_env(char **env, const char *name)
1190 for (i=0; env[i] != NULL; i++)
1191 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1192 return(env[i] + len + 1);
1197 * Read /etc/default/login.
1198 * We pick up the PATH (or SUPATH for root) and UMASK.
1201 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1203 char **tmpenv = NULL, *var;
1204 u_int i, tmpenvsize = 0;
1208 * We don't want to copy the whole file to the child's environment,
1209 * so we use a temporary environment and copy the variables we're
1212 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1218 var = child_get_env(tmpenv, "SUPATH");
1220 var = child_get_env(tmpenv, "PATH");
1222 child_set_env(env, envsize, "PATH", var);
1224 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1225 if (sscanf(var, "%5lo", &mask) == 1)
1226 umask((mode_t)mask);
1228 for (i = 0; tmpenv[i] != NULL; i++)
1232 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1235 copy_environment(char **source, char ***env, u_int *envsize)
1237 char *var_name, *var_val;
1243 for(i = 0; source[i] != NULL; i++) {
1244 var_name = xstrdup(source[i]);
1245 if ((var_val = strstr(var_name, "=")) == NULL) {
1251 debug3("Copy environment: %s=%s", var_name, var_val);
1252 child_set_env(env, envsize, var_name, var_val);
1259 do_setup_env(Session *s, const char *shell)
1264 struct passwd *pw = s->pw;
1265 #ifndef HAVE_LOGIN_CAP
1269 /* Initialize the environment. */
1271 env = xcalloc(envsize, sizeof(char *));
1276 * The Windows environment contains some setting which are
1277 * important for a running system. They must not be dropped.
1282 p = fetch_windows_environment();
1283 copy_environment(p, &env, &envsize);
1284 free_windows_environment(p);
1289 /* Allow any GSSAPI methods that we've used to alter
1290 * the childs environment as they see fit
1292 ssh_gssapi_do_child(&env, &envsize);
1295 if (!options.use_login) {
1296 /* Set basic environment. */
1297 for (i = 0; i < s->num_env; i++)
1298 child_set_env(&env, &envsize, s->env[i].name,
1301 child_set_env(&env, &envsize, "USER", pw->pw_name);
1302 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1304 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1306 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1307 #ifdef HAVE_LOGIN_CAP
1308 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1309 child_set_env(&env, &envsize, "PATH",
1310 _PATH_STDPATH_WITH_SCP);
1312 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1313 #else /* HAVE_LOGIN_CAP */
1314 # ifndef HAVE_CYGWIN
1316 * There's no standard path on Windows. The path contains
1317 * important components pointing to the system directories,
1318 * needed for loading shared libraries. So the path better
1319 * remains intact here.
1321 # ifdef HAVE_ETC_DEFAULT_LOGIN
1322 read_etc_default_login(&env, &envsize, pw->pw_uid);
1323 path = child_get_env(env, "PATH");
1324 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1325 if (path == NULL || *path == '\0') {
1326 child_set_env(&env, &envsize, "PATH",
1327 s->pw->pw_uid == 0 ?
1328 SUPERUSER_PATH : _PATH_STDPATH_WITH_SCP);
1330 # endif /* HAVE_CYGWIN */
1331 #endif /* HAVE_LOGIN_CAP */
1333 snprintf(buf, sizeof buf, "%.200s/%.50s",
1334 _PATH_MAILDIR, pw->pw_name);
1335 child_set_env(&env, &envsize, "MAIL", buf);
1337 /* Normal systems set SHELL by default. */
1338 child_set_env(&env, &envsize, "SHELL", shell);
1341 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1343 #ifdef GSI /* GSI shared libs typically installed in non-system locations. */
1347 if ((cp = getenv("LD_LIBRARY_PATH")) != NULL)
1348 child_set_env(&env, &envsize, "LD_LIBRARY_PATH", cp);
1349 if ((cp = getenv("LIBPATH")) != NULL)
1350 child_set_env(&env, &envsize, "LIBPATH", cp);
1351 if ((cp = getenv("SHLIB_PATH")) != NULL)
1352 child_set_env(&env, &envsize, "SHLIB_PATH", cp);
1353 if ((cp = getenv("LD_LIBRARYN32_PATH")) != NULL)
1354 child_set_env(&env, &envsize, "LD_LIBRARYN32_PATH",cp);
1355 if ((cp = getenv("LD_LIBRARY64_PATH")) != NULL)
1356 child_set_env(&env, &envsize, "LD_LIBRARY64_PATH",cp);
1357 if ((cp = getenv("GLOBUS_LOCATION")) != NULL)
1358 child_set_env(&env, &envsize, "GLOBUS_LOCATION",cp);
1362 /* Set custom environment options from RSA authentication. */
1363 if (!options.use_login) {
1364 while (custom_environment) {
1365 struct envstring *ce = custom_environment;
1368 for (i = 0; str[i] != '=' && str[i]; i++)
1370 if (str[i] == '=') {
1372 child_set_env(&env, &envsize, str, str + i + 1);
1374 custom_environment = ce->next;
1380 /* SSH_CLIENT deprecated */
1381 snprintf(buf, sizeof buf, "%.50s %d %d",
1382 get_remote_ipaddr(), get_remote_port(), get_local_port());
1383 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1385 laddr = get_local_ipaddr(packet_get_connection_in());
1386 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1387 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1389 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1392 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1394 child_set_env(&env, &envsize, "TERM", s->term);
1396 child_set_env(&env, &envsize, "DISPLAY", s->display);
1397 if (original_command)
1398 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1402 if (cray_tmpdir[0] != '\0')
1403 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1404 #endif /* _UNICOS */
1407 * Since we clear KRB5CCNAME at startup, if it's set now then it
1408 * must have been set by a native authentication method (eg AIX or
1409 * SIA), so copy it to the child.
1414 if ((cp = getenv("KRB5CCNAME")) != NULL)
1415 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1422 if ((cp = getenv("AUTHSTATE")) != NULL)
1423 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1424 read_environment_file(&env, &envsize, "/etc/environment");
1428 if (s->authctxt->krb5_ccname)
1429 child_set_env(&env, &envsize, "KRB5CCNAME",
1430 s->authctxt->krb5_ccname);
1434 * Pull in any environment variables that may have
1437 if (options.use_pam) {
1440 p = fetch_pam_child_environment();
1441 copy_environment(p, &env, &envsize);
1442 free_pam_environment(p);
1444 p = fetch_pam_environment();
1445 copy_environment(p, &env, &envsize);
1446 free_pam_environment(p);
1448 #endif /* USE_PAM */
1450 if (auth_sock_name != NULL)
1451 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1454 /* read $HOME/.ssh/environment. */
1455 if (options.permit_user_env && !options.use_login) {
1456 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1457 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1458 read_environment_file(&env, &envsize, buf);
1461 /* dump the environment */
1462 fprintf(stderr, "Environment:\n");
1463 for (i = 0; env[i]; i++)
1464 fprintf(stderr, " %.200s\n", env[i]);
1470 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1471 * first in this order).
1474 do_rc_files(Session *s, const char *shell)
1482 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1484 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1485 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1486 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1487 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1488 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1490 fprintf(stderr, "Running %s\n", cmd);
1491 f = popen(cmd, "w");
1494 fprintf(f, "%s %s\n", s->auth_proto,
1498 fprintf(stderr, "Could not run %s\n",
1500 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1501 snprintf(cmd, sizeof cmd, "%s %s", _PATH_BSHELL,
1502 _PATH_SSH_SYSTEM_RC);
1504 fprintf(stderr, "Running %s\n", cmd);
1505 f = popen(cmd, "w");
1508 fprintf(f, "%s %s\n", s->auth_proto,
1512 fprintf(stderr, "Could not run %s\n",
1513 _PATH_SSH_SYSTEM_RC);
1514 } else if (do_xauth && options.xauth_location != NULL) {
1515 /* Add authority data to .Xauthority if appropriate. */
1518 "Running %.500s remove %.100s\n",
1519 options.xauth_location, s->auth_display);
1521 "%.500s add %.100s %.100s %.100s\n",
1522 options.xauth_location, s->auth_display,
1523 s->auth_proto, s->auth_data);
1525 snprintf(cmd, sizeof cmd, "%s -q -",
1526 options.xauth_location);
1527 f = popen(cmd, "w");
1529 fprintf(f, "remove %s\n",
1531 fprintf(f, "add %s %s %s\n",
1532 s->auth_display, s->auth_proto,
1536 fprintf(stderr, "Could not run %s\n",
1543 do_nologin(struct passwd *pw)
1548 #ifdef HAVE_LOGIN_CAP
1549 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1550 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1551 _PATH_NOLOGIN), "r");
1554 f = fopen(_PATH_NOLOGIN, "r");
1557 /* /etc/nologin exists. Print its contents and exit. */
1558 logit("User %.100s not allowed because %s exists",
1559 pw->pw_name, _PATH_NOLOGIN);
1560 while (fgets(buf, sizeof(buf), f))
1569 * Chroot into a directory after checking it for safety: all path components
1570 * must be root-owned directories with strict permissions.
1573 safely_chroot(const char *path, uid_t uid)
1576 char component[MAXPATHLEN];
1580 fatal("chroot path does not begin at root");
1581 if (strlen(path) >= sizeof(component))
1582 fatal("chroot path too long");
1585 * Descend the path, checking that each component is a
1586 * root-owned directory with strict permissions.
1588 for (cp = path; cp != NULL;) {
1589 if ((cp = strchr(cp, '/')) == NULL)
1590 strlcpy(component, path, sizeof(component));
1593 memcpy(component, path, cp - path);
1594 component[cp - path] = '\0';
1597 debug3("%s: checking '%s'", __func__, component);
1599 if (stat(component, &st) != 0)
1600 fatal("%s: stat(\"%s\"): %s", __func__,
1601 component, strerror(errno));
1602 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1603 fatal("bad ownership or modes for chroot "
1604 "directory %s\"%s\"",
1605 cp == NULL ? "" : "component ", component);
1606 if (!S_ISDIR(st.st_mode))
1607 fatal("chroot path %s\"%s\" is not a directory",
1608 cp == NULL ? "" : "component ", component);
1612 if (chdir(path) == -1)
1613 fatal("Unable to chdir to chroot path \"%s\": "
1614 "%s", path, strerror(errno));
1615 if (chroot(path) == -1)
1616 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1617 if (chdir("/") == -1)
1618 fatal("%s: chdir(/) after chroot: %s",
1619 __func__, strerror(errno));
1620 verbose("Changed root directory to \"%s\"", path);
1623 /* Set login name, uid, gid, and groups. */
1625 do_setusercontext(struct passwd *pw)
1627 char *chroot_path, *tmp;
1630 /* Cache selinux status for later use */
1631 (void)ssh_selinux_enabled();
1635 if (getuid() == 0 || geteuid() == 0)
1636 #endif /* HAVE_CYGWIN */
1639 #ifdef HAVE_SETPCRED
1640 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1641 fatal("Failed to set process credentials");
1642 #endif /* HAVE_SETPCRED */
1643 #ifdef HAVE_LOGIN_CAP
1648 if (options.use_pam) {
1649 do_pam_setcred(use_privsep);
1651 # endif /* USE_PAM */
1652 if (setusercontext(lc, pw, pw->pw_uid,
1653 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1654 perror("unable to set user context");
1658 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1659 /* Sets login uid for accounting */
1660 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1661 error("setluid: %s", strerror(errno));
1662 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1664 if (setlogin(pw->pw_name) < 0)
1665 error("setlogin failed: %s", strerror(errno));
1666 if (setgid(pw->pw_gid) < 0) {
1670 /* Initialize the group list. */
1671 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1672 perror("initgroups");
1678 * PAM credentials may take the form of supplementary groups.
1679 * These will have been wiped by the above initgroups() call.
1680 * Reestablish them here.
1682 if (options.use_pam) {
1683 do_pam_setcred(use_privsep);
1685 # endif /* USE_PAM */
1686 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1687 irix_setusercontext(pw);
1688 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1693 if (set_id(pw->pw_name) != 0) {
1696 # endif /* USE_LIBIAF */
1699 if (options.chroot_directory != NULL &&
1700 strcasecmp(options.chroot_directory, "none") != 0) {
1701 tmp = tilde_expand_filename(options.chroot_directory,
1703 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1704 "u", pw->pw_name, (char *)NULL);
1705 safely_chroot(chroot_path, pw->pw_uid);
1710 #ifdef HAVE_LOGIN_CAP
1711 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1712 perror("unable to set user context (setuser)");
1716 /* Permanently switch to the desired uid. */
1717 permanently_set_uid(pw);
1724 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1725 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1728 ssh_selinux_setup_exec_context(pw->pw_name);
1733 do_pwchange(Session *s)
1736 fprintf(stderr, "WARNING: Your password has expired.\n");
1737 if (s->ttyfd != -1) {
1739 "You must change your password now and login again!\n");
1740 #ifdef PASSWD_NEEDS_USERNAME
1741 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1744 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1749 "Password change required but no TTY available.\n");
1755 launch_login(struct passwd *pw, const char *hostname)
1757 /* Launch login(1). */
1759 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1760 #ifdef xxxLOGIN_NEEDS_TERM
1761 (s->term ? s->term : "unknown"),
1762 #endif /* LOGIN_NEEDS_TERM */
1763 #ifdef LOGIN_NO_ENDOPT
1764 "-p", "-f", pw->pw_name, (char *)NULL);
1766 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1769 /* Login couldn't be executed, die. */
1776 child_close_fds(void)
1780 if (packet_get_connection_in() == packet_get_connection_out())
1781 close(packet_get_connection_in());
1783 close(packet_get_connection_in());
1784 close(packet_get_connection_out());
1787 * Close all descriptors related to channels. They will still remain
1788 * open in the parent.
1790 /* XXX better use close-on-exec? -markus */
1791 channel_close_all();
1794 * Close any extra file descriptors. Note that there may still be
1795 * descriptors left by system functions. They will be closed later.
1800 * Close any extra open file descriptors so that we don't have them
1801 * hanging around in clients. Note that we want to do this after
1802 * initgroups, because at least on Solaris 2.3 it leaves file
1805 for (i = 3; i < 64; i++)
1810 * Performs common processing for the child, such as setting up the
1811 * environment, closing extra file descriptors, setting the user and group
1812 * ids, and executing the command or shell.
1816 do_child(Session *s, const char *command)
1818 extern char **environ;
1820 char *argv[ARGV_MAX];
1821 const char *shell, *shell0, *hostname = NULL;
1822 struct passwd *pw = s->pw;
1826 /* Default place to look for aklog. */
1828 #define KPROGDIR AKLOG_PATH
1830 #define KPROGDIR "/usr/bin/aklog"
1831 #endif /* AKLOG_PATH */
1835 #endif /* AFS_KRB5 */
1837 /* remove hostkey from the child's memory */
1838 destroy_sensitive_data();
1840 /* Force a password change */
1841 if (s->authctxt->force_pwchange) {
1842 do_setusercontext(pw);
1848 /* login(1) is only called if we execute the login shell */
1849 if (options.use_login && command != NULL)
1850 options.use_login = 0;
1853 cray_setup(pw->pw_uid, pw->pw_name, command);
1854 #endif /* _UNICOS */
1857 * Login(1) does this as well, and it needs uid 0 for the "-h"
1858 * switch, so we let login(1) to this for us.
1860 if (!options.use_login) {
1862 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1863 if (!check_quietlogin(s, command))
1865 #else /* HAVE_OSF_SIA */
1866 /* When PAM is enabled we rely on it to do the nologin check */
1867 if (!options.use_pam)
1869 do_setusercontext(pw);
1871 * PAM session modules in do_setusercontext may have
1872 * generated messages, so if this in an interactive
1873 * login then display them too.
1875 if (!check_quietlogin(s, command))
1877 #endif /* HAVE_OSF_SIA */
1881 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1882 debug3("PAM session not opened, exiting");
1889 * Get the shell from the password data. An empty shell field is
1890 * legal, and means /bin/sh.
1892 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1895 * Make sure $SHELL points to the shell from the password file,
1896 * even if shell is overridden from login.conf
1898 env = do_setup_env(s, shell);
1900 #ifdef HAVE_LOGIN_CAP
1901 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1904 /* we have to stash the hostname before we close our socket. */
1905 if (options.use_login)
1906 hostname = get_remote_name_or_ip(utmp_len,
1909 * Close the connection descriptors; note that this is the child, and
1910 * the server will still have the socket open, and it is important
1911 * that we do not shutdown it. Note that the descriptors cannot be
1912 * closed before building the environment, as we call
1913 * get_remote_ipaddr there.
1918 * Must take new environment into use so that .ssh/rc,
1919 * /etc/ssh/sshrc and xauth are run in the proper environment.
1923 #if defined(KRB5) && defined(USE_AFS)
1925 * At this point, we check to see if AFS is active and if we have
1926 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1927 * if we can (and need to) extend the ticket into an AFS token. If
1928 * we don't do this, we run into potential problems if the user's
1929 * home directory is in AFS and it's not world-readable.
1932 if (options.kerberos_get_afs_token && k_hasafs() &&
1933 (s->authctxt->krb5_ctx != NULL)) {
1936 debug("Getting AFS token");
1940 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1941 krb5_afslog(s->authctxt->krb5_ctx,
1942 s->authctxt->krb5_fwd_ccache, cell, NULL);
1944 krb5_afslog_home(s->authctxt->krb5_ctx,
1945 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1951 /* User has authenticated, and if a ticket was going to be
1952 * passed we would have it. KRB5CCNAME should already be set.
1953 * Now try to get an AFS token using aklog.
1955 if (k_hasafs()) { /* Do we have AFS? */
1957 aklog_path = xstrdup(KPROGDIR);
1960 * Make sure it exists before we try to run it
1962 if (stat(aklog_path, &st) == 0) {
1963 debug("Running %s to get afs token.",aklog_path);
1966 debug("%s does not exist.",aklog_path);
1971 #endif /* AFS_KRB5 */
1973 #ifdef SESSION_HOOKS
1974 if (options.session_hooks_allow &&
1975 options.session_hooks_startup_cmd)
1977 execute_session_hook(options.session_hooks_startup_cmd,
1980 options.session_hooks_shutdown_cmd != NULL);
1984 /* Change current directory to the user's home directory. */
1985 if (chdir(pw->pw_dir) < 0) {
1986 /* Suppress missing homedir warning for chroot case */
1987 #ifdef HAVE_LOGIN_CAP
1988 r = login_getcapbool(lc, "requirehome", 0);
1990 if (r || options.chroot_directory == NULL)
1991 fprintf(stderr, "Could not chdir to home "
1992 "directory %s: %s\n", pw->pw_dir,
1998 closefrom(STDERR_FILENO + 1);
2000 if (!options.use_login)
2001 do_rc_files(s, shell);
2003 /* restore SIGPIPE for child */
2004 signal(SIGPIPE, SIG_DFL);
2006 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
2007 extern int optind, optreset;
2011 setproctitle("%s@internal-sftp-server", s->pw->pw_name);
2012 args = strdup(command ? command : "sftp-server");
2013 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
2014 if (i < ARGV_MAX - 1)
2017 optind = optreset = 1;
2018 __progname = argv[0];
2019 exit(sftp_server_main(i, argv, s->pw));
2022 if (options.use_login) {
2023 launch_login(pw, hostname);
2027 /* Get the last component of the shell name. */
2028 if ((shell0 = strrchr(shell, '/')) != NULL)
2034 * If we have no command, execute the shell. In this case, the shell
2035 * name to be passed in argv[0] is preceded by '-' to indicate that
2036 * this is a login shell.
2041 /* Start the shell. Set initial character to '-'. */
2044 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
2045 >= sizeof(argv0) - 1) {
2051 /* Execute the shell. */
2054 execve(shell, argv, environ);
2056 /* Executing the shell failed. */
2061 * Execute the command using the user's shell. This uses the -c
2062 * option to execute the command.
2064 argv[0] = (char *) shell0;
2066 argv[2] = (char *) command;
2068 execve(shell, argv, environ);
2074 session_unused(int id)
2076 debug3("%s: session id %d unused", __func__, id);
2077 if (id >= options.max_sessions ||
2078 id >= sessions_nalloc) {
2079 fatal("%s: insane session id %d (max %d nalloc %d)",
2080 __func__, id, options.max_sessions, sessions_nalloc);
2082 bzero(&sessions[id], sizeof(*sessions));
2083 sessions[id].self = id;
2084 sessions[id].used = 0;
2085 sessions[id].chanid = -1;
2086 sessions[id].ptyfd = -1;
2087 sessions[id].ttyfd = -1;
2088 sessions[id].ptymaster = -1;
2089 sessions[id].x11_chanids = NULL;
2090 sessions[id].next_unused = sessions_first_unused;
2091 sessions_first_unused = id;
2099 if (sessions_first_unused == -1) {
2100 if (sessions_nalloc >= options.max_sessions)
2102 debug2("%s: allocate (allocated %d max %d)",
2103 __func__, sessions_nalloc, options.max_sessions);
2104 tmp = xrealloc(sessions, sessions_nalloc + 1,
2107 error("%s: cannot allocate %d sessions",
2108 __func__, sessions_nalloc + 1);
2112 session_unused(sessions_nalloc++);
2115 if (sessions_first_unused >= sessions_nalloc ||
2116 sessions_first_unused < 0) {
2117 fatal("%s: insane first_unused %d max %d nalloc %d",
2118 __func__, sessions_first_unused, options.max_sessions,
2122 s = &sessions[sessions_first_unused];
2124 fatal("%s: session %d already used",
2125 __func__, sessions_first_unused);
2127 sessions_first_unused = s->next_unused;
2129 s->next_unused = -1;
2130 debug("session_new: session %d", s->self);
2139 for (i = 0; i < sessions_nalloc; i++) {
2140 Session *s = &sessions[i];
2142 debug("dump: used %d next_unused %d session %d %p "
2143 "channel %d pid %ld",
2154 session_open(Authctxt *authctxt, int chanid)
2156 Session *s = session_new();
2157 debug("session_open: channel %d", chanid);
2159 error("no more sessions");
2162 s->authctxt = authctxt;
2163 s->pw = authctxt->pw;
2164 if (s->pw == NULL || !authctxt->valid)
2165 fatal("no user for session %d", s->self);
2166 debug("session_open: session %d: link with channel %d", s->self, chanid);
2172 session_by_tty(char *tty)
2175 for (i = 0; i < sessions_nalloc; i++) {
2176 Session *s = &sessions[i];
2177 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2178 debug("session_by_tty: session %d tty %s", i, tty);
2182 debug("session_by_tty: unknown tty %.100s", tty);
2188 session_by_channel(int id)
2191 for (i = 0; i < sessions_nalloc; i++) {
2192 Session *s = &sessions[i];
2193 if (s->used && s->chanid == id) {
2194 debug("session_by_channel: session %d channel %d",
2199 debug("session_by_channel: unknown channel %d", id);
2205 session_by_x11_channel(int id)
2209 for (i = 0; i < sessions_nalloc; i++) {
2210 Session *s = &sessions[i];
2212 if (s->x11_chanids == NULL || !s->used)
2214 for (j = 0; s->x11_chanids[j] != -1; j++) {
2215 if (s->x11_chanids[j] == id) {
2216 debug("session_by_x11_channel: session %d "
2217 "channel %d", s->self, id);
2222 debug("session_by_x11_channel: unknown channel %d", id);
2228 session_by_pid(pid_t pid)
2231 debug("session_by_pid: pid %ld", (long)pid);
2232 for (i = 0; i < sessions_nalloc; i++) {
2233 Session *s = &sessions[i];
2234 if (s->used && s->pid == pid)
2237 error("session_by_pid: unknown pid %ld", (long)pid);
2243 session_window_change_req(Session *s)
2245 s->col = packet_get_int();
2246 s->row = packet_get_int();
2247 s->xpixel = packet_get_int();
2248 s->ypixel = packet_get_int();
2250 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2255 session_pty_req(Session *s)
2261 debug("Allocating a pty not permitted for this authentication.");
2264 if (s->ttyfd != -1) {
2265 packet_disconnect("Protocol error: you already have a pty.");
2269 s->term = packet_get_string(&len);
2272 s->col = packet_get_int();
2273 s->row = packet_get_int();
2275 s->row = packet_get_int();
2276 s->col = packet_get_int();
2278 s->xpixel = packet_get_int();
2279 s->ypixel = packet_get_int();
2281 if (strcmp(s->term, "") == 0) {
2286 /* Allocate a pty and open it. */
2287 debug("Allocating pty.");
2288 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2295 error("session_pty_req: session %d alloc failed", s->self);
2298 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2300 /* for SSH1 the tty modes length is not given */
2302 n_bytes = packet_remaining();
2303 tty_parse_modes(s->ttyfd, &n_bytes);
2306 pty_setowner(s->pw, s->tty);
2308 /* Set window size from the packet. */
2309 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2312 session_proctitle(s);
2317 session_subsystem_req(Session *s)
2322 char *prog, *cmd, *subsys = packet_get_string(&len);
2326 logit("subsystem request for %.100s", subsys);
2328 for (i = 0; i < options.num_subsystems; i++) {
2329 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2330 prog = options.subsystem_command[i];
2331 cmd = options.subsystem_args[i];
2332 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
2333 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2334 } else if (stat(prog, &st) < 0) {
2335 error("subsystem: cannot stat %s: %s", prog,
2339 s->is_subsystem = SUBSYSTEM_EXT;
2341 debug("subsystem: exec() %s", cmd);
2342 success = do_exec(s, cmd) == 0;
2348 logit("subsystem request for %.100s failed, subsystem not found",
2356 session_x11_req(Session *s)
2360 if (s->auth_proto != NULL || s->auth_data != NULL) {
2361 error("session_x11_req: session %d: "
2362 "x11 forwarding already active", s->self);
2365 s->single_connection = packet_get_char();
2366 s->auth_proto = packet_get_string(NULL);
2367 s->auth_data = packet_get_string(NULL);
2368 s->screen = packet_get_int();
2371 success = session_setup_x11fwd(s);
2373 xfree(s->auth_proto);
2374 xfree(s->auth_data);
2375 s->auth_proto = NULL;
2376 s->auth_data = NULL;
2382 session_shell_req(Session *s)
2385 return do_exec(s, NULL) == 0;
2389 session_exec_req(Session *s)
2393 char *command = packet_get_string(&len);
2395 success = do_exec(s, command) == 0;
2401 session_break_req(Session *s)
2404 packet_get_int(); /* ignored */
2407 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
2413 session_env_req(Session *s)
2416 u_int name_len, val_len, i;
2418 name = packet_get_string(&name_len);
2419 val = packet_get_string(&val_len);
2422 /* Don't set too many environment variables */
2423 if (s->num_env > 128) {
2424 debug2("Ignoring env request %s: too many env vars", name);
2428 for (i = 0; i < options.num_accept_env; i++) {
2429 if (match_pattern(name, options.accept_env[i])) {
2430 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2431 s->env = xrealloc(s->env, s->num_env + 1,
2433 s->env[s->num_env].name = name;
2434 s->env[s->num_env].val = val;
2439 debug2("Ignoring env request %s: disallowed name", name);
2448 session_auth_agent_req(Session *s)
2450 static int called = 0;
2452 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2453 debug("session_auth_agent_req: no_agent_forwarding_flag");
2460 return auth_input_request_forwarding(s->pw);
2465 session_input_channel_req(Channel *c, const char *rtype)
2470 if ((s = session_by_channel(c->self)) == NULL) {
2471 logit("session_input_channel_req: no session %d req %.100s",
2475 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2478 * a session is in LARVAL state until a shell, a command
2479 * or a subsystem is executed
2481 if (c->type == SSH_CHANNEL_LARVAL) {
2482 if (strcmp(rtype, "shell") == 0) {
2483 success = session_shell_req(s);
2484 } else if (strcmp(rtype, "exec") == 0) {
2485 success = session_exec_req(s);
2486 } else if (strcmp(rtype, "pty-req") == 0) {
2487 success = session_pty_req(s);
2488 } else if (strcmp(rtype, "x11-req") == 0) {
2489 success = session_x11_req(s);
2490 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2491 success = session_auth_agent_req(s);
2492 } else if (strcmp(rtype, "subsystem") == 0) {
2493 success = session_subsystem_req(s);
2494 } else if (strcmp(rtype, "env") == 0) {
2495 success = session_env_req(s);
2498 if (strcmp(rtype, "window-change") == 0) {
2499 success = session_window_change_req(s);
2500 } else if (strcmp(rtype, "break") == 0) {
2501 success = session_break_req(s);
2508 session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
2511 fatal("session_set_fds: called for proto != 2.0");
2513 * now that have a child and a pipe to the child,
2514 * we can activate our channel and register the fd's
2516 if (s->chanid == -1)
2517 fatal("no channel for session %d", s->self);
2518 if (options.hpn_disabled)
2519 channel_set_fds(s->chanid,
2521 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2522 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2524 channel_set_fds(s->chanid,
2526 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2527 1, is_tty, options.hpn_buffer_size);
2531 * Function to perform pty cleanup. Also called if we get aborted abnormally
2532 * (e.g., due to a dropped connection).
2535 session_pty_cleanup2(Session *s)
2538 error("session_pty_cleanup: no session");
2544 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2546 /* Record that the user has logged out. */
2548 record_logout(s->pid, s->tty, s->pw->pw_name);
2550 /* Release the pseudo-tty. */
2552 pty_release(s->tty);
2555 * Close the server side of the socket pairs. We must do this after
2556 * the pty cleanup, so that another process doesn't get this pty
2557 * while we're still cleaning up.
2559 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2560 error("close(s->ptymaster/%d): %s",
2561 s->ptymaster, strerror(errno));
2563 /* unlink pty from session */
2568 session_pty_cleanup(Session *s)
2570 PRIVSEP(session_pty_cleanup2(s));
2576 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2591 return "SIG@openssh.com";
2595 session_close_x11(int id)
2599 if ((c = channel_by_id(id)) == NULL) {
2600 debug("session_close_x11: x11 channel %d missing", id);
2602 /* Detach X11 listener */
2603 debug("session_close_x11: detach x11 channel %d", id);
2604 channel_cancel_cleanup(id);
2605 if (c->ostate != CHAN_OUTPUT_CLOSED)
2611 session_close_single_x11(int id, void *arg)
2616 debug3("session_close_single_x11: channel %d", id);
2617 channel_cancel_cleanup(id);
2618 if ((s = session_by_x11_channel(id)) == NULL)
2619 fatal("session_close_single_x11: no x11 channel %d", id);
2620 for (i = 0; s->x11_chanids[i] != -1; i++) {
2621 debug("session_close_single_x11: session %d: "
2622 "closing channel %d", s->self, s->x11_chanids[i]);
2624 * The channel "id" is already closing, but make sure we
2625 * close all of its siblings.
2627 if (s->x11_chanids[i] != id)
2628 session_close_x11(s->x11_chanids[i]);
2630 xfree(s->x11_chanids);
2631 s->x11_chanids = NULL;
2636 if (s->auth_proto) {
2637 xfree(s->auth_proto);
2638 s->auth_proto = NULL;
2641 xfree(s->auth_data);
2642 s->auth_data = NULL;
2644 if (s->auth_display) {
2645 xfree(s->auth_display);
2646 s->auth_display = NULL;
2651 session_exit_message(Session *s, int status)
2655 if ((c = channel_lookup(s->chanid)) == NULL)
2656 fatal("session_exit_message: session %d: no channel %d",
2657 s->self, s->chanid);
2658 debug("session_exit_message: session %d channel %d pid %ld",
2659 s->self, s->chanid, (long)s->pid);
2661 if (WIFEXITED(status)) {
2662 channel_request_start(s->chanid, "exit-status", 0);
2663 packet_put_int(WEXITSTATUS(status));
2665 } else if (WIFSIGNALED(status)) {
2666 channel_request_start(s->chanid, "exit-signal", 0);
2667 packet_put_cstring(sig2name(WTERMSIG(status)));
2669 packet_put_char(WCOREDUMP(status)? 1 : 0);
2670 #else /* WCOREDUMP */
2672 #endif /* WCOREDUMP */
2673 packet_put_cstring("");
2674 packet_put_cstring("");
2677 /* Some weird exit cause. Just exit. */
2678 packet_disconnect("wait returned status %04x.", status);
2681 /* disconnect channel */
2682 debug("session_exit_message: release channel %d", s->chanid);
2685 * Adjust cleanup callback attachment to send close messages when
2686 * the channel gets EOF. The session will be then be closed
2687 * by session_close_by_channel when the childs close their fds.
2689 channel_register_cleanup(c->self, session_close_by_channel, 1);
2692 * emulate a write failure with 'chan_write_failed', nobody will be
2693 * interested in data we write.
2694 * Note that we must not call 'chan_read_failed', since there could
2695 * be some more data waiting in the pipe.
2697 if (c->ostate != CHAN_OUTPUT_CLOSED)
2698 chan_write_failed(c);
2702 session_close(Session *s)
2706 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2708 session_pty_cleanup(s);
2714 xfree(s->x11_chanids);
2715 if (s->auth_display)
2716 xfree(s->auth_display);
2718 xfree(s->auth_data);
2720 xfree(s->auth_proto);
2721 if (s->env != NULL) {
2722 for (i = 0; i < s->num_env; i++) {
2723 xfree(s->env[i].name);
2724 xfree(s->env[i].val);
2728 session_proctitle(s);
2729 session_unused(s->self);
2733 session_close_by_pid(pid_t pid, int status)
2735 Session *s = session_by_pid(pid);
2737 debug("session_close_by_pid: no session for pid %ld",
2741 if (s->chanid != -1)
2742 session_exit_message(s, status);
2744 session_pty_cleanup(s);
2749 * this is called when a channel dies before
2750 * the session 'child' itself dies
2753 session_close_by_channel(int id, void *arg)
2755 Session *s = session_by_channel(id);
2759 debug("session_close_by_channel: no session for id %d", id);
2762 debug("session_close_by_channel: channel %d child %ld",
2765 debug("session_close_by_channel: channel %d: has child", id);
2767 * delay detach of session, but release pty, since
2768 * the fd's to the child are already closed
2771 session_pty_cleanup(s);
2774 /* detach by removing callback */
2775 channel_cancel_cleanup(s->chanid);
2777 /* Close any X11 listeners associated with this session */
2778 if (s->x11_chanids != NULL) {
2779 for (i = 0; s->x11_chanids[i] != -1; i++) {
2780 session_close_x11(s->x11_chanids[i]);
2781 s->x11_chanids[i] = -1;
2790 session_destroy_all(void (*closefunc)(Session *))
2793 for (i = 0; i < sessions_nalloc; i++) {
2794 Session *s = &sessions[i];
2796 if (closefunc != NULL)
2805 session_tty_list(void)
2807 static char buf[1024];
2812 for (i = 0; i < sessions_nalloc; i++) {
2813 Session *s = &sessions[i];
2814 if (s->used && s->ttyfd != -1) {
2816 if (strncmp(s->tty, "/dev/", 5) != 0) {
2817 cp = strrchr(s->tty, '/');
2818 cp = (cp == NULL) ? s->tty : cp + 1;
2823 strlcat(buf, ",", sizeof buf);
2824 strlcat(buf, cp, sizeof buf);
2828 strlcpy(buf, "notty", sizeof buf);
2833 session_proctitle(Session *s)
2836 error("no user for session %d", s->self);
2838 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2842 session_setup_x11fwd(Session *s)
2845 char display[512], auth_display[512];
2846 char hostname[MAXHOSTNAMELEN];
2849 if (no_x11_forwarding_flag) {
2850 packet_send_debug("X11 forwarding disabled in user configuration file.");
2853 if (!options.x11_forwarding) {
2854 debug("X11 forwarding disabled in server configuration file.");
2857 if (!options.xauth_location ||
2858 (stat(options.xauth_location, &st) == -1)) {
2859 packet_send_debug("No xauth program; cannot forward with spoofing.");
2862 if (options.use_login) {
2863 packet_send_debug("X11 forwarding disabled; "
2864 "not compatible with UseLogin=yes.");
2867 if (s->display != NULL) {
2868 debug("X11 display already set.");
2871 if (x11_create_display_inet(options.x11_display_offset,
2872 options.x11_use_localhost, s->single_connection,
2873 &s->display_number, &s->x11_chanids) == -1) {
2874 debug("x11_create_display_inet failed.");
2877 for (i = 0; s->x11_chanids[i] != -1; i++) {
2878 channel_register_cleanup(s->x11_chanids[i],
2879 session_close_single_x11, 0);
2882 /* Set up a suitable value for the DISPLAY variable. */
2883 if (gethostname(hostname, sizeof(hostname)) < 0)
2884 fatal("gethostname: %.100s", strerror(errno));
2886 * auth_display must be used as the displayname when the
2887 * authorization entry is added with xauth(1). This will be
2888 * different than the DISPLAY string for localhost displays.
2890 if (options.x11_use_localhost) {
2891 snprintf(display, sizeof display, "localhost:%u.%u",
2892 s->display_number, s->screen);
2893 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2894 s->display_number, s->screen);
2895 s->display = xstrdup(display);
2896 s->auth_display = xstrdup(auth_display);
2898 #ifdef IPADDR_IN_DISPLAY
2900 struct in_addr my_addr;
2902 he = gethostbyname(hostname);
2904 error("Can't get IP address for X11 DISPLAY.");
2905 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2908 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2909 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2910 s->display_number, s->screen);
2912 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2913 s->display_number, s->screen);
2915 s->display = xstrdup(display);
2916 s->auth_display = xstrdup(display);
2923 do_authenticated2(Authctxt *authctxt)
2925 server_loop2(authctxt);
2929 do_cleanup(Authctxt *authctxt)
2931 static int called = 0;
2933 debug("do_cleanup");
2935 /* no cleanup if we're in the child for login shell */
2939 /* avoid double cleanup */
2944 if (authctxt == NULL)
2948 if (options.use_pam) {
2950 sshpam_thread_cleanup();
2954 if (!authctxt->authenticated)
2958 if (options.kerberos_ticket_cleanup &&
2960 krb5_cleanup_proc(authctxt);
2964 if (compat20 && options.gss_cleanup_creds)
2965 ssh_gssapi_cleanup_creds();
2968 /* remove agent socket */
2969 auth_sock_cleanup_proc(authctxt->pw);
2972 * Cleanup ptys/utmp only if privsep is disabled,
2973 * or if running in monitor.
2975 if (!use_privsep || mm_is_monitor())
2976 session_destroy_all(session_pty_cleanup2);