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", _PATH_STDPATH);
1311 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1312 #else /* HAVE_LOGIN_CAP */
1313 # ifndef HAVE_CYGWIN
1315 * There's no standard path on Windows. The path contains
1316 * important components pointing to the system directories,
1317 * needed for loading shared libraries. So the path better
1318 * remains intact here.
1320 # ifdef HAVE_ETC_DEFAULT_LOGIN
1321 read_etc_default_login(&env, &envsize, pw->pw_uid);
1322 path = child_get_env(env, "PATH");
1323 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1324 if (path == NULL || *path == '\0') {
1325 child_set_env(&env, &envsize, "PATH",
1326 s->pw->pw_uid == 0 ?
1327 SUPERUSER_PATH : _PATH_STDPATH);
1329 # endif /* HAVE_CYGWIN */
1330 #endif /* HAVE_LOGIN_CAP */
1332 snprintf(buf, sizeof buf, "%.200s/%.50s",
1333 _PATH_MAILDIR, pw->pw_name);
1334 child_set_env(&env, &envsize, "MAIL", buf);
1336 /* Normal systems set SHELL by default. */
1337 child_set_env(&env, &envsize, "SHELL", shell);
1340 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1342 #ifdef GSI /* GSI shared libs typically installed in non-system locations. */
1346 if ((cp = getenv("LD_LIBRARY_PATH")) != NULL)
1347 child_set_env(&env, &envsize, "LD_LIBRARY_PATH", cp);
1348 if ((cp = getenv("LIBPATH")) != NULL)
1349 child_set_env(&env, &envsize, "LIBPATH", cp);
1350 if ((cp = getenv("SHLIB_PATH")) != NULL)
1351 child_set_env(&env, &envsize, "SHLIB_PATH", cp);
1352 if ((cp = getenv("LD_LIBRARYN32_PATH")) != NULL)
1353 child_set_env(&env, &envsize, "LD_LIBRARYN32_PATH",cp);
1354 if ((cp = getenv("LD_LIBRARY64_PATH")) != NULL)
1355 child_set_env(&env, &envsize, "LD_LIBRARY64_PATH",cp);
1359 /* Set custom environment options from RSA authentication. */
1360 if (!options.use_login) {
1361 while (custom_environment) {
1362 struct envstring *ce = custom_environment;
1365 for (i = 0; str[i] != '=' && str[i]; i++)
1367 if (str[i] == '=') {
1369 child_set_env(&env, &envsize, str, str + i + 1);
1371 custom_environment = ce->next;
1377 /* SSH_CLIENT deprecated */
1378 snprintf(buf, sizeof buf, "%.50s %d %d",
1379 get_remote_ipaddr(), get_remote_port(), get_local_port());
1380 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1382 laddr = get_local_ipaddr(packet_get_connection_in());
1383 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1384 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1386 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1389 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1391 child_set_env(&env, &envsize, "TERM", s->term);
1393 child_set_env(&env, &envsize, "DISPLAY", s->display);
1394 if (original_command)
1395 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1399 if (cray_tmpdir[0] != '\0')
1400 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1401 #endif /* _UNICOS */
1404 * Since we clear KRB5CCNAME at startup, if it's set now then it
1405 * must have been set by a native authentication method (eg AIX or
1406 * SIA), so copy it to the child.
1411 if ((cp = getenv("KRB5CCNAME")) != NULL)
1412 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1419 if ((cp = getenv("AUTHSTATE")) != NULL)
1420 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1421 read_environment_file(&env, &envsize, "/etc/environment");
1425 if (s->authctxt->krb5_ccname)
1426 child_set_env(&env, &envsize, "KRB5CCNAME",
1427 s->authctxt->krb5_ccname);
1431 * Pull in any environment variables that may have
1434 if (options.use_pam) {
1437 p = fetch_pam_child_environment();
1438 copy_environment(p, &env, &envsize);
1439 free_pam_environment(p);
1441 p = fetch_pam_environment();
1442 copy_environment(p, &env, &envsize);
1443 free_pam_environment(p);
1445 #endif /* USE_PAM */
1447 if (auth_sock_name != NULL)
1448 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1451 /* read $HOME/.ssh/environment. */
1452 if (options.permit_user_env && !options.use_login) {
1453 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1454 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1455 read_environment_file(&env, &envsize, buf);
1458 /* dump the environment */
1459 fprintf(stderr, "Environment:\n");
1460 for (i = 0; env[i]; i++)
1461 fprintf(stderr, " %.200s\n", env[i]);
1467 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1468 * first in this order).
1471 do_rc_files(Session *s, const char *shell)
1479 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1481 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1482 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1483 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1484 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1485 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1487 fprintf(stderr, "Running %s\n", cmd);
1488 f = popen(cmd, "w");
1491 fprintf(f, "%s %s\n", s->auth_proto,
1495 fprintf(stderr, "Could not run %s\n",
1497 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1499 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1500 _PATH_SSH_SYSTEM_RC);
1501 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1504 fprintf(f, "%s %s\n", s->auth_proto,
1508 fprintf(stderr, "Could not run %s\n",
1509 _PATH_SSH_SYSTEM_RC);
1510 } else if (do_xauth && options.xauth_location != NULL) {
1511 /* Add authority data to .Xauthority if appropriate. */
1514 "Running %.500s remove %.100s\n",
1515 options.xauth_location, s->auth_display);
1517 "%.500s add %.100s %.100s %.100s\n",
1518 options.xauth_location, s->auth_display,
1519 s->auth_proto, s->auth_data);
1521 snprintf(cmd, sizeof cmd, "%s -q -",
1522 options.xauth_location);
1523 f = popen(cmd, "w");
1525 fprintf(f, "remove %s\n",
1527 fprintf(f, "add %s %s %s\n",
1528 s->auth_display, s->auth_proto,
1532 fprintf(stderr, "Could not run %s\n",
1539 do_nologin(struct passwd *pw)
1544 #ifdef HAVE_LOGIN_CAP
1545 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1546 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1547 _PATH_NOLOGIN), "r");
1550 f = fopen(_PATH_NOLOGIN, "r");
1553 /* /etc/nologin exists. Print its contents and exit. */
1554 logit("User %.100s not allowed because %s exists",
1555 pw->pw_name, _PATH_NOLOGIN);
1556 while (fgets(buf, sizeof(buf), f))
1565 * Chroot into a directory after checking it for safety: all path components
1566 * must be root-owned directories with strict permissions.
1569 safely_chroot(const char *path, uid_t uid)
1572 char component[MAXPATHLEN];
1576 fatal("chroot path does not begin at root");
1577 if (strlen(path) >= sizeof(component))
1578 fatal("chroot path too long");
1581 * Descend the path, checking that each component is a
1582 * root-owned directory with strict permissions.
1584 for (cp = path; cp != NULL;) {
1585 if ((cp = strchr(cp, '/')) == NULL)
1586 strlcpy(component, path, sizeof(component));
1589 memcpy(component, path, cp - path);
1590 component[cp - path] = '\0';
1593 debug3("%s: checking '%s'", __func__, component);
1595 if (stat(component, &st) != 0)
1596 fatal("%s: stat(\"%s\"): %s", __func__,
1597 component, strerror(errno));
1598 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1599 fatal("bad ownership or modes for chroot "
1600 "directory %s\"%s\"",
1601 cp == NULL ? "" : "component ", component);
1602 if (!S_ISDIR(st.st_mode))
1603 fatal("chroot path %s\"%s\" is not a directory",
1604 cp == NULL ? "" : "component ", component);
1608 if (chdir(path) == -1)
1609 fatal("Unable to chdir to chroot path \"%s\": "
1610 "%s", path, strerror(errno));
1611 if (chroot(path) == -1)
1612 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1613 if (chdir("/") == -1)
1614 fatal("%s: chdir(/) after chroot: %s",
1615 __func__, strerror(errno));
1616 verbose("Changed root directory to \"%s\"", path);
1619 /* Set login name, uid, gid, and groups. */
1621 do_setusercontext(struct passwd *pw)
1623 char *chroot_path, *tmp;
1626 /* Cache selinux status for later use */
1627 (void)ssh_selinux_enabled();
1631 if (getuid() == 0 || geteuid() == 0)
1632 #endif /* HAVE_CYGWIN */
1635 #ifdef HAVE_SETPCRED
1636 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1637 fatal("Failed to set process credentials");
1638 #endif /* HAVE_SETPCRED */
1639 #ifdef HAVE_LOGIN_CAP
1644 if (options.use_pam) {
1645 do_pam_setcred(use_privsep);
1647 # endif /* USE_PAM */
1648 if (setusercontext(lc, pw, pw->pw_uid,
1649 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1650 perror("unable to set user context");
1654 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1655 /* Sets login uid for accounting */
1656 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1657 error("setluid: %s", strerror(errno));
1658 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1660 if (setlogin(pw->pw_name) < 0)
1661 error("setlogin failed: %s", strerror(errno));
1662 if (setgid(pw->pw_gid) < 0) {
1666 /* Initialize the group list. */
1667 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1668 perror("initgroups");
1674 * PAM credentials may take the form of supplementary groups.
1675 * These will have been wiped by the above initgroups() call.
1676 * Reestablish them here.
1678 if (options.use_pam) {
1679 do_pam_setcred(use_privsep);
1681 # endif /* USE_PAM */
1682 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1683 irix_setusercontext(pw);
1684 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1689 if (set_id(pw->pw_name) != 0) {
1692 # endif /* USE_LIBIAF */
1695 if (options.chroot_directory != NULL &&
1696 strcasecmp(options.chroot_directory, "none") != 0) {
1697 tmp = tilde_expand_filename(options.chroot_directory,
1699 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1700 "u", pw->pw_name, (char *)NULL);
1701 safely_chroot(chroot_path, pw->pw_uid);
1706 #ifdef HAVE_LOGIN_CAP
1707 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1708 perror("unable to set user context (setuser)");
1712 /* Permanently switch to the desired uid. */
1713 permanently_set_uid(pw);
1720 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1721 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1724 ssh_selinux_setup_exec_context(pw->pw_name);
1729 do_pwchange(Session *s)
1732 fprintf(stderr, "WARNING: Your password has expired.\n");
1733 if (s->ttyfd != -1) {
1735 "You must change your password now and login again!\n");
1736 #ifdef PASSWD_NEEDS_USERNAME
1737 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1740 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1745 "Password change required but no TTY available.\n");
1751 launch_login(struct passwd *pw, const char *hostname)
1753 /* Launch login(1). */
1755 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1756 #ifdef xxxLOGIN_NEEDS_TERM
1757 (s->term ? s->term : "unknown"),
1758 #endif /* LOGIN_NEEDS_TERM */
1759 #ifdef LOGIN_NO_ENDOPT
1760 "-p", "-f", pw->pw_name, (char *)NULL);
1762 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1765 /* Login couldn't be executed, die. */
1772 child_close_fds(void)
1776 if (packet_get_connection_in() == packet_get_connection_out())
1777 close(packet_get_connection_in());
1779 close(packet_get_connection_in());
1780 close(packet_get_connection_out());
1783 * Close all descriptors related to channels. They will still remain
1784 * open in the parent.
1786 /* XXX better use close-on-exec? -markus */
1787 channel_close_all();
1790 * Close any extra file descriptors. Note that there may still be
1791 * descriptors left by system functions. They will be closed later.
1796 * Close any extra open file descriptors so that we don't have them
1797 * hanging around in clients. Note that we want to do this after
1798 * initgroups, because at least on Solaris 2.3 it leaves file
1801 for (i = 3; i < 64; i++)
1806 * Performs common processing for the child, such as setting up the
1807 * environment, closing extra file descriptors, setting the user and group
1808 * ids, and executing the command or shell.
1812 do_child(Session *s, const char *command)
1814 extern char **environ;
1816 char *argv[ARGV_MAX];
1817 const char *shell, *shell0, *hostname = NULL;
1818 struct passwd *pw = s->pw;
1822 /* Default place to look for aklog. */
1824 #define KPROGDIR AKLOG_PATH
1826 #define KPROGDIR "/usr/bin/aklog"
1827 #endif /* AKLOG_PATH */
1831 #endif /* AFS_KRB5 */
1833 /* remove hostkey from the child's memory */
1834 destroy_sensitive_data();
1836 /* Force a password change */
1837 if (s->authctxt->force_pwchange) {
1838 do_setusercontext(pw);
1844 /* login(1) is only called if we execute the login shell */
1845 if (options.use_login && command != NULL)
1846 options.use_login = 0;
1849 cray_setup(pw->pw_uid, pw->pw_name, command);
1850 #endif /* _UNICOS */
1853 * Login(1) does this as well, and it needs uid 0 for the "-h"
1854 * switch, so we let login(1) to this for us.
1856 if (!options.use_login) {
1858 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1859 if (!check_quietlogin(s, command))
1861 #else /* HAVE_OSF_SIA */
1862 /* When PAM is enabled we rely on it to do the nologin check */
1863 if (!options.use_pam)
1865 do_setusercontext(pw);
1867 * PAM session modules in do_setusercontext may have
1868 * generated messages, so if this in an interactive
1869 * login then display them too.
1871 if (!check_quietlogin(s, command))
1873 #endif /* HAVE_OSF_SIA */
1877 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1878 debug3("PAM session not opened, exiting");
1885 * Get the shell from the password data. An empty shell field is
1886 * legal, and means /bin/sh.
1888 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1891 * Make sure $SHELL points to the shell from the password file,
1892 * even if shell is overridden from login.conf
1894 env = do_setup_env(s, shell);
1896 #ifdef HAVE_LOGIN_CAP
1897 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1900 /* we have to stash the hostname before we close our socket. */
1901 if (options.use_login)
1902 hostname = get_remote_name_or_ip(utmp_len,
1905 * Close the connection descriptors; note that this is the child, and
1906 * the server will still have the socket open, and it is important
1907 * that we do not shutdown it. Note that the descriptors cannot be
1908 * closed before building the environment, as we call
1909 * get_remote_ipaddr there.
1914 * Must take new environment into use so that .ssh/rc,
1915 * /etc/ssh/sshrc and xauth are run in the proper environment.
1919 #if defined(KRB5) && defined(USE_AFS)
1921 * At this point, we check to see if AFS is active and if we have
1922 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1923 * if we can (and need to) extend the ticket into an AFS token. If
1924 * we don't do this, we run into potential problems if the user's
1925 * home directory is in AFS and it's not world-readable.
1928 if (options.kerberos_get_afs_token && k_hasafs() &&
1929 (s->authctxt->krb5_ctx != NULL)) {
1932 debug("Getting AFS token");
1936 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1937 krb5_afslog(s->authctxt->krb5_ctx,
1938 s->authctxt->krb5_fwd_ccache, cell, NULL);
1940 krb5_afslog_home(s->authctxt->krb5_ctx,
1941 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1947 /* User has authenticated, and if a ticket was going to be
1948 * passed we would have it. KRB5CCNAME should already be set.
1949 * Now try to get an AFS token using aklog.
1951 if (k_hasafs()) { /* Do we have AFS? */
1953 aklog_path = xstrdup(KPROGDIR);
1956 * Make sure it exists before we try to run it
1958 if (stat(aklog_path, &st) == 0) {
1959 debug("Running %s to get afs token.",aklog_path);
1962 debug("%s does not exist.",aklog_path);
1967 #endif /* AFS_KRB5 */
1969 #ifdef SESSION_HOOKS
1970 if (options.session_hooks_allow &&
1971 options.session_hooks_startup_cmd)
1973 execute_session_hook(options.session_hooks_startup_cmd,
1976 options.session_hooks_shutdown_cmd != NULL);
1980 /* Change current directory to the user's home directory. */
1981 if (chdir(pw->pw_dir) < 0) {
1982 /* Suppress missing homedir warning for chroot case */
1983 #ifdef HAVE_LOGIN_CAP
1984 r = login_getcapbool(lc, "requirehome", 0);
1986 if (r || options.chroot_directory == NULL)
1987 fprintf(stderr, "Could not chdir to home "
1988 "directory %s: %s\n", pw->pw_dir,
1994 closefrom(STDERR_FILENO + 1);
1996 if (!options.use_login)
1997 do_rc_files(s, shell);
1999 /* restore SIGPIPE for child */
2000 signal(SIGPIPE, SIG_DFL);
2002 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
2003 extern int optind, optreset;
2007 setproctitle("%s@internal-sftp-server", s->pw->pw_name);
2008 args = strdup(command ? command : "sftp-server");
2009 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
2010 if (i < ARGV_MAX - 1)
2013 optind = optreset = 1;
2014 __progname = argv[0];
2015 exit(sftp_server_main(i, argv, s->pw));
2018 if (options.use_login) {
2019 launch_login(pw, hostname);
2023 /* Get the last component of the shell name. */
2024 if ((shell0 = strrchr(shell, '/')) != NULL)
2030 * If we have no command, execute the shell. In this case, the shell
2031 * name to be passed in argv[0] is preceded by '-' to indicate that
2032 * this is a login shell.
2037 /* Start the shell. Set initial character to '-'. */
2040 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
2041 >= sizeof(argv0) - 1) {
2047 /* Execute the shell. */
2050 execve(shell, argv, environ);
2052 /* Executing the shell failed. */
2057 * Execute the command using the user's shell. This uses the -c
2058 * option to execute the command.
2060 argv[0] = (char *) shell0;
2062 argv[2] = (char *) command;
2064 execve(shell, argv, environ);
2070 session_unused(int id)
2072 debug3("%s: session id %d unused", __func__, id);
2073 if (id >= options.max_sessions ||
2074 id >= sessions_nalloc) {
2075 fatal("%s: insane session id %d (max %d nalloc %d)",
2076 __func__, id, options.max_sessions, sessions_nalloc);
2078 bzero(&sessions[id], sizeof(*sessions));
2079 sessions[id].self = id;
2080 sessions[id].used = 0;
2081 sessions[id].chanid = -1;
2082 sessions[id].ptyfd = -1;
2083 sessions[id].ttyfd = -1;
2084 sessions[id].ptymaster = -1;
2085 sessions[id].x11_chanids = NULL;
2086 sessions[id].next_unused = sessions_first_unused;
2087 sessions_first_unused = id;
2095 if (sessions_first_unused == -1) {
2096 if (sessions_nalloc >= options.max_sessions)
2098 debug2("%s: allocate (allocated %d max %d)",
2099 __func__, sessions_nalloc, options.max_sessions);
2100 tmp = xrealloc(sessions, sessions_nalloc + 1,
2103 error("%s: cannot allocate %d sessions",
2104 __func__, sessions_nalloc + 1);
2108 session_unused(sessions_nalloc++);
2111 if (sessions_first_unused >= sessions_nalloc ||
2112 sessions_first_unused < 0) {
2113 fatal("%s: insane first_unused %d max %d nalloc %d",
2114 __func__, sessions_first_unused, options.max_sessions,
2118 s = &sessions[sessions_first_unused];
2120 fatal("%s: session %d already used",
2121 __func__, sessions_first_unused);
2123 sessions_first_unused = s->next_unused;
2125 s->next_unused = -1;
2126 debug("session_new: session %d", s->self);
2135 for (i = 0; i < sessions_nalloc; i++) {
2136 Session *s = &sessions[i];
2138 debug("dump: used %d next_unused %d session %d %p "
2139 "channel %d pid %ld",
2150 session_open(Authctxt *authctxt, int chanid)
2152 Session *s = session_new();
2153 debug("session_open: channel %d", chanid);
2155 error("no more sessions");
2158 s->authctxt = authctxt;
2159 s->pw = authctxt->pw;
2160 if (s->pw == NULL || !authctxt->valid)
2161 fatal("no user for session %d", s->self);
2162 debug("session_open: session %d: link with channel %d", s->self, chanid);
2168 session_by_tty(char *tty)
2171 for (i = 0; i < sessions_nalloc; i++) {
2172 Session *s = &sessions[i];
2173 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2174 debug("session_by_tty: session %d tty %s", i, tty);
2178 debug("session_by_tty: unknown tty %.100s", tty);
2184 session_by_channel(int id)
2187 for (i = 0; i < sessions_nalloc; i++) {
2188 Session *s = &sessions[i];
2189 if (s->used && s->chanid == id) {
2190 debug("session_by_channel: session %d channel %d",
2195 debug("session_by_channel: unknown channel %d", id);
2201 session_by_x11_channel(int id)
2205 for (i = 0; i < sessions_nalloc; i++) {
2206 Session *s = &sessions[i];
2208 if (s->x11_chanids == NULL || !s->used)
2210 for (j = 0; s->x11_chanids[j] != -1; j++) {
2211 if (s->x11_chanids[j] == id) {
2212 debug("session_by_x11_channel: session %d "
2213 "channel %d", s->self, id);
2218 debug("session_by_x11_channel: unknown channel %d", id);
2224 session_by_pid(pid_t pid)
2227 debug("session_by_pid: pid %ld", (long)pid);
2228 for (i = 0; i < sessions_nalloc; i++) {
2229 Session *s = &sessions[i];
2230 if (s->used && s->pid == pid)
2233 error("session_by_pid: unknown pid %ld", (long)pid);
2239 session_window_change_req(Session *s)
2241 s->col = packet_get_int();
2242 s->row = packet_get_int();
2243 s->xpixel = packet_get_int();
2244 s->ypixel = packet_get_int();
2246 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2251 session_pty_req(Session *s)
2257 debug("Allocating a pty not permitted for this authentication.");
2260 if (s->ttyfd != -1) {
2261 packet_disconnect("Protocol error: you already have a pty.");
2265 s->term = packet_get_string(&len);
2268 s->col = packet_get_int();
2269 s->row = packet_get_int();
2271 s->row = packet_get_int();
2272 s->col = packet_get_int();
2274 s->xpixel = packet_get_int();
2275 s->ypixel = packet_get_int();
2277 if (strcmp(s->term, "") == 0) {
2282 /* Allocate a pty and open it. */
2283 debug("Allocating pty.");
2284 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2291 error("session_pty_req: session %d alloc failed", s->self);
2294 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2296 /* for SSH1 the tty modes length is not given */
2298 n_bytes = packet_remaining();
2299 tty_parse_modes(s->ttyfd, &n_bytes);
2302 pty_setowner(s->pw, s->tty);
2304 /* Set window size from the packet. */
2305 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2308 session_proctitle(s);
2313 session_subsystem_req(Session *s)
2318 char *prog, *cmd, *subsys = packet_get_string(&len);
2322 logit("subsystem request for %.100s", subsys);
2324 for (i = 0; i < options.num_subsystems; i++) {
2325 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2326 prog = options.subsystem_command[i];
2327 cmd = options.subsystem_args[i];
2328 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
2329 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2330 } else if (stat(prog, &st) < 0) {
2331 error("subsystem: cannot stat %s: %s", prog,
2335 s->is_subsystem = SUBSYSTEM_EXT;
2337 debug("subsystem: exec() %s", cmd);
2338 success = do_exec(s, cmd) == 0;
2344 logit("subsystem request for %.100s failed, subsystem not found",
2352 session_x11_req(Session *s)
2356 if (s->auth_proto != NULL || s->auth_data != NULL) {
2357 error("session_x11_req: session %d: "
2358 "x11 forwarding already active", s->self);
2361 s->single_connection = packet_get_char();
2362 s->auth_proto = packet_get_string(NULL);
2363 s->auth_data = packet_get_string(NULL);
2364 s->screen = packet_get_int();
2367 success = session_setup_x11fwd(s);
2369 xfree(s->auth_proto);
2370 xfree(s->auth_data);
2371 s->auth_proto = NULL;
2372 s->auth_data = NULL;
2378 session_shell_req(Session *s)
2381 return do_exec(s, NULL) == 0;
2385 session_exec_req(Session *s)
2389 char *command = packet_get_string(&len);
2391 success = do_exec(s, command) == 0;
2397 session_break_req(Session *s)
2400 packet_get_int(); /* ignored */
2403 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
2409 session_env_req(Session *s)
2412 u_int name_len, val_len, i;
2414 name = packet_get_string(&name_len);
2415 val = packet_get_string(&val_len);
2418 /* Don't set too many environment variables */
2419 if (s->num_env > 128) {
2420 debug2("Ignoring env request %s: too many env vars", name);
2424 for (i = 0; i < options.num_accept_env; i++) {
2425 if (match_pattern(name, options.accept_env[i])) {
2426 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2427 s->env = xrealloc(s->env, s->num_env + 1,
2429 s->env[s->num_env].name = name;
2430 s->env[s->num_env].val = val;
2435 debug2("Ignoring env request %s: disallowed name", name);
2444 session_auth_agent_req(Session *s)
2446 static int called = 0;
2448 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2449 debug("session_auth_agent_req: no_agent_forwarding_flag");
2456 return auth_input_request_forwarding(s->pw);
2461 session_input_channel_req(Channel *c, const char *rtype)
2466 if ((s = session_by_channel(c->self)) == NULL) {
2467 logit("session_input_channel_req: no session %d req %.100s",
2471 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2474 * a session is in LARVAL state until a shell, a command
2475 * or a subsystem is executed
2477 if (c->type == SSH_CHANNEL_LARVAL) {
2478 if (strcmp(rtype, "shell") == 0) {
2479 success = session_shell_req(s);
2480 } else if (strcmp(rtype, "exec") == 0) {
2481 success = session_exec_req(s);
2482 } else if (strcmp(rtype, "pty-req") == 0) {
2483 success = session_pty_req(s);
2484 } else if (strcmp(rtype, "x11-req") == 0) {
2485 success = session_x11_req(s);
2486 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2487 success = session_auth_agent_req(s);
2488 } else if (strcmp(rtype, "subsystem") == 0) {
2489 success = session_subsystem_req(s);
2490 } else if (strcmp(rtype, "env") == 0) {
2491 success = session_env_req(s);
2494 if (strcmp(rtype, "window-change") == 0) {
2495 success = session_window_change_req(s);
2496 } else if (strcmp(rtype, "break") == 0) {
2497 success = session_break_req(s);
2504 session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
2507 fatal("session_set_fds: called for proto != 2.0");
2509 * now that have a child and a pipe to the child,
2510 * we can activate our channel and register the fd's
2512 if (s->chanid == -1)
2513 fatal("no channel for session %d", s->self);
2514 if (options.hpn_disabled)
2515 channel_set_fds(s->chanid,
2517 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2518 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2520 channel_set_fds(s->chanid,
2522 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2523 1, is_tty, options.hpn_buffer_size);
2527 * Function to perform pty cleanup. Also called if we get aborted abnormally
2528 * (e.g., due to a dropped connection).
2531 session_pty_cleanup2(Session *s)
2534 error("session_pty_cleanup: no session");
2540 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2542 /* Record that the user has logged out. */
2544 record_logout(s->pid, s->tty, s->pw->pw_name);
2546 /* Release the pseudo-tty. */
2548 pty_release(s->tty);
2551 * Close the server side of the socket pairs. We must do this after
2552 * the pty cleanup, so that another process doesn't get this pty
2553 * while we're still cleaning up.
2555 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2556 error("close(s->ptymaster/%d): %s",
2557 s->ptymaster, strerror(errno));
2559 /* unlink pty from session */
2564 session_pty_cleanup(Session *s)
2566 PRIVSEP(session_pty_cleanup2(s));
2572 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2587 return "SIG@openssh.com";
2591 session_close_x11(int id)
2595 if ((c = channel_by_id(id)) == NULL) {
2596 debug("session_close_x11: x11 channel %d missing", id);
2598 /* Detach X11 listener */
2599 debug("session_close_x11: detach x11 channel %d", id);
2600 channel_cancel_cleanup(id);
2601 if (c->ostate != CHAN_OUTPUT_CLOSED)
2607 session_close_single_x11(int id, void *arg)
2612 debug3("session_close_single_x11: channel %d", id);
2613 channel_cancel_cleanup(id);
2614 if ((s = session_by_x11_channel(id)) == NULL)
2615 fatal("session_close_single_x11: no x11 channel %d", id);
2616 for (i = 0; s->x11_chanids[i] != -1; i++) {
2617 debug("session_close_single_x11: session %d: "
2618 "closing channel %d", s->self, s->x11_chanids[i]);
2620 * The channel "id" is already closing, but make sure we
2621 * close all of its siblings.
2623 if (s->x11_chanids[i] != id)
2624 session_close_x11(s->x11_chanids[i]);
2626 xfree(s->x11_chanids);
2627 s->x11_chanids = NULL;
2632 if (s->auth_proto) {
2633 xfree(s->auth_proto);
2634 s->auth_proto = NULL;
2637 xfree(s->auth_data);
2638 s->auth_data = NULL;
2640 if (s->auth_display) {
2641 xfree(s->auth_display);
2642 s->auth_display = NULL;
2647 session_exit_message(Session *s, int status)
2651 if ((c = channel_lookup(s->chanid)) == NULL)
2652 fatal("session_exit_message: session %d: no channel %d",
2653 s->self, s->chanid);
2654 debug("session_exit_message: session %d channel %d pid %ld",
2655 s->self, s->chanid, (long)s->pid);
2657 if (WIFEXITED(status)) {
2658 channel_request_start(s->chanid, "exit-status", 0);
2659 packet_put_int(WEXITSTATUS(status));
2661 } else if (WIFSIGNALED(status)) {
2662 channel_request_start(s->chanid, "exit-signal", 0);
2663 packet_put_cstring(sig2name(WTERMSIG(status)));
2665 packet_put_char(WCOREDUMP(status)? 1 : 0);
2666 #else /* WCOREDUMP */
2668 #endif /* WCOREDUMP */
2669 packet_put_cstring("");
2670 packet_put_cstring("");
2673 /* Some weird exit cause. Just exit. */
2674 packet_disconnect("wait returned status %04x.", status);
2677 /* disconnect channel */
2678 debug("session_exit_message: release channel %d", s->chanid);
2681 * Adjust cleanup callback attachment to send close messages when
2682 * the channel gets EOF. The session will be then be closed
2683 * by session_close_by_channel when the childs close their fds.
2685 channel_register_cleanup(c->self, session_close_by_channel, 1);
2688 * emulate a write failure with 'chan_write_failed', nobody will be
2689 * interested in data we write.
2690 * Note that we must not call 'chan_read_failed', since there could
2691 * be some more data waiting in the pipe.
2693 if (c->ostate != CHAN_OUTPUT_CLOSED)
2694 chan_write_failed(c);
2698 session_close(Session *s)
2702 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2704 session_pty_cleanup(s);
2710 xfree(s->x11_chanids);
2711 if (s->auth_display)
2712 xfree(s->auth_display);
2714 xfree(s->auth_data);
2716 xfree(s->auth_proto);
2717 if (s->env != NULL) {
2718 for (i = 0; i < s->num_env; i++) {
2719 xfree(s->env[i].name);
2720 xfree(s->env[i].val);
2724 session_proctitle(s);
2725 session_unused(s->self);
2729 session_close_by_pid(pid_t pid, int status)
2731 Session *s = session_by_pid(pid);
2733 debug("session_close_by_pid: no session for pid %ld",
2737 if (s->chanid != -1)
2738 session_exit_message(s, status);
2740 session_pty_cleanup(s);
2745 * this is called when a channel dies before
2746 * the session 'child' itself dies
2749 session_close_by_channel(int id, void *arg)
2751 Session *s = session_by_channel(id);
2755 debug("session_close_by_channel: no session for id %d", id);
2758 debug("session_close_by_channel: channel %d child %ld",
2761 debug("session_close_by_channel: channel %d: has child", id);
2763 * delay detach of session, but release pty, since
2764 * the fd's to the child are already closed
2767 session_pty_cleanup(s);
2770 /* detach by removing callback */
2771 channel_cancel_cleanup(s->chanid);
2773 /* Close any X11 listeners associated with this session */
2774 if (s->x11_chanids != NULL) {
2775 for (i = 0; s->x11_chanids[i] != -1; i++) {
2776 session_close_x11(s->x11_chanids[i]);
2777 s->x11_chanids[i] = -1;
2786 session_destroy_all(void (*closefunc)(Session *))
2789 for (i = 0; i < sessions_nalloc; i++) {
2790 Session *s = &sessions[i];
2792 if (closefunc != NULL)
2801 session_tty_list(void)
2803 static char buf[1024];
2808 for (i = 0; i < sessions_nalloc; i++) {
2809 Session *s = &sessions[i];
2810 if (s->used && s->ttyfd != -1) {
2812 if (strncmp(s->tty, "/dev/", 5) != 0) {
2813 cp = strrchr(s->tty, '/');
2814 cp = (cp == NULL) ? s->tty : cp + 1;
2819 strlcat(buf, ",", sizeof buf);
2820 strlcat(buf, cp, sizeof buf);
2824 strlcpy(buf, "notty", sizeof buf);
2829 session_proctitle(Session *s)
2832 error("no user for session %d", s->self);
2834 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2838 session_setup_x11fwd(Session *s)
2841 char display[512], auth_display[512];
2842 char hostname[MAXHOSTNAMELEN];
2845 if (no_x11_forwarding_flag) {
2846 packet_send_debug("X11 forwarding disabled in user configuration file.");
2849 if (!options.x11_forwarding) {
2850 debug("X11 forwarding disabled in server configuration file.");
2853 if (!options.xauth_location ||
2854 (stat(options.xauth_location, &st) == -1)) {
2855 packet_send_debug("No xauth program; cannot forward with spoofing.");
2858 if (options.use_login) {
2859 packet_send_debug("X11 forwarding disabled; "
2860 "not compatible with UseLogin=yes.");
2863 if (s->display != NULL) {
2864 debug("X11 display already set.");
2867 if (x11_create_display_inet(options.x11_display_offset,
2868 options.x11_use_localhost, s->single_connection,
2869 &s->display_number, &s->x11_chanids) == -1) {
2870 debug("x11_create_display_inet failed.");
2873 for (i = 0; s->x11_chanids[i] != -1; i++) {
2874 channel_register_cleanup(s->x11_chanids[i],
2875 session_close_single_x11, 0);
2878 /* Set up a suitable value for the DISPLAY variable. */
2879 if (gethostname(hostname, sizeof(hostname)) < 0)
2880 fatal("gethostname: %.100s", strerror(errno));
2882 * auth_display must be used as the displayname when the
2883 * authorization entry is added with xauth(1). This will be
2884 * different than the DISPLAY string for localhost displays.
2886 if (options.x11_use_localhost) {
2887 snprintf(display, sizeof display, "localhost:%u.%u",
2888 s->display_number, s->screen);
2889 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2890 s->display_number, s->screen);
2891 s->display = xstrdup(display);
2892 s->auth_display = xstrdup(auth_display);
2894 #ifdef IPADDR_IN_DISPLAY
2896 struct in_addr my_addr;
2898 he = gethostbyname(hostname);
2900 error("Can't get IP address for X11 DISPLAY.");
2901 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2904 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2905 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2906 s->display_number, s->screen);
2908 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2909 s->display_number, s->screen);
2911 s->display = xstrdup(display);
2912 s->auth_display = xstrdup(display);
2919 do_authenticated2(Authctxt *authctxt)
2921 server_loop2(authctxt);
2925 do_cleanup(Authctxt *authctxt)
2927 static int called = 0;
2929 debug("do_cleanup");
2931 /* no cleanup if we're in the child for login shell */
2935 /* avoid double cleanup */
2940 if (authctxt == NULL)
2944 if (options.use_pam) {
2946 sshpam_thread_cleanup();
2950 if (!authctxt->authenticated)
2954 if (options.kerberos_ticket_cleanup &&
2956 krb5_cleanup_proc(authctxt);
2960 if (compat20 && options.gss_cleanup_creds)
2961 ssh_gssapi_cleanup_creds();
2964 /* remove agent socket */
2965 auth_sock_cleanup_proc(authctxt->pw);
2968 * Cleanup ptys/utmp only if privsep is disabled,
2969 * or if running in monitor.
2971 if (!use_privsep || mm_is_monitor())
2972 session_destroy_all(session_pty_cleanup2);