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, options.hpn_disabled,
400 options.hpn_buffer_size) < 0) {
401 debug("Port forwarding failed.");
407 case SSH_CMSG_MAX_PACKET_SIZE:
408 if (packet_set_maxsize(packet_get_int()) > 0)
412 case SSH_CMSG_EXEC_SHELL:
413 case SSH_CMSG_EXEC_CMD:
414 if (type == SSH_CMSG_EXEC_CMD) {
415 command = packet_get_string(&dlen);
416 debug("Exec command '%.500s'", command);
417 if (do_exec(s, command) != 0)
419 "command execution failed");
422 if (do_exec(s, NULL) != 0)
424 "shell execution failed");
432 * Any unknown messages in this phase are ignored,
433 * and a failure message is returned.
435 logit("Unknown packet type received after authentication: %d", type);
437 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
441 /* Enable compression now that we have replied if appropriate. */
442 if (enable_compression_after_reply) {
443 enable_compression_after_reply = 0;
444 packet_start_compression(compression_level);
451 * This is called to fork and execute a command when we have no tty. This
452 * will call do_child from the child, and server_loop from the parent after
453 * setting up file descriptors and such.
456 do_exec_no_pty(Session *s, const char *command)
461 int pin[2], pout[2], perr[2];
463 /* Allocate pipes for communicating with the program. */
465 error("%s: pipe in: %.100s", __func__, strerror(errno));
468 if (pipe(pout) < 0) {
469 error("%s: pipe out: %.100s", __func__, strerror(errno));
474 if (pipe(perr) < 0) {
475 error("%s: pipe err: %.100s", __func__, strerror(errno));
483 int inout[2], err[2];
485 /* Uses socket pairs to communicate with the program. */
486 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
487 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
490 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
491 error("%s: socketpair #2: %.100s", __func__, strerror(errno));
499 fatal("do_exec_no_pty: no session");
501 session_proctitle(s);
503 /* Fork the child. */
504 switch ((pid = fork())) {
506 error("%s: fork: %.100s", __func__, strerror(errno));
524 /* Child. Reinitialize the log since the pid has changed. */
525 log_init(__progname, options.log_level,
526 options.log_facility, log_stderr);
529 * Create a new session and process group since the 4.4BSD
530 * setlogin() affects the entire process group.
533 error("setsid failed: %.100s", strerror(errno));
537 * Redirect stdin. We close the parent side of the socket
538 * pair, and make the child side the standard input.
541 if (dup2(pin[0], 0) < 0)
542 perror("dup2 stdin");
545 /* Redirect stdout. */
547 if (dup2(pout[1], 1) < 0)
548 perror("dup2 stdout");
551 /* Redirect stderr. */
553 if (dup2(perr[1], 2) < 0)
554 perror("dup2 stderr");
558 * Redirect stdin, stdout, and stderr. Stdin and stdout will
559 * use the same socket, as some programs (particularly rdist)
560 * seem to depend on it.
564 if (dup2(inout[0], 0) < 0) /* stdin */
565 perror("dup2 stdin");
566 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
567 perror("dup2 stdout");
569 if (dup2(err[0], 2) < 0) /* stderr */
570 perror("dup2 stderr");
576 cray_init_job(s->pw); /* set up cray jid and tmpdir */
579 /* Do processing for the child (exec command etc). */
580 do_child(s, command);
587 signal(WJSIGNAL, cray_job_termination_handler);
591 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
595 /* Set interactive/non-interactive mode. */
596 packet_set_interactive(s->display != NULL);
599 * Clear loginmsg, since it's the child's responsibility to display
600 * it to the user, otherwise multiple sessions may accumulate
601 * multiple copies of the login messages.
603 buffer_clear(&loginmsg);
606 /* We are the parent. Close the child sides of the pipes. */
612 if (s->is_subsystem) {
616 session_set_fds(s, pin[1], pout[0], perr[0], 0);
618 /* Enter the interactive session. */
619 server_loop(pid, pin[1], pout[0], perr[0]);
620 /* server_loop has closed pin[1], pout[0], and perr[0]. */
623 /* We are the parent. Close the child sides of the socket pairs. */
628 * Enter the interactive session. Note: server_loop must be able to
629 * handle the case that fdin and fdout are the same.
632 session_set_fds(s, inout[1], inout[1],
633 s->is_subsystem ? -1 : err[1], 0);
637 server_loop(pid, inout[1], inout[1], err[1]);
638 /* server_loop has closed inout[1] and err[1]. */
645 * This is called to fork and execute a command when we have a tty. This
646 * will call do_child from the child, and server_loop from the parent after
647 * setting up file descriptors, controlling tty, updating wtmp, utmp,
648 * lastlog, and other such operations.
651 do_exec_pty(Session *s, const char *command)
653 int fdout, ptyfd, ttyfd, ptymaster;
657 fatal("do_exec_pty: no session");
662 * Create another descriptor of the pty master side for use as the
663 * standard input. We could use the original descriptor, but this
664 * simplifies code in server_loop. The descriptor is bidirectional.
665 * Do this before forking (and cleanup in the child) so as to
666 * detect and gracefully fail out-of-fd conditions.
668 if ((fdout = dup(ptyfd)) < 0) {
669 error("%s: dup #1: %s", __func__, strerror(errno));
674 /* we keep a reference to the pty master */
675 if ((ptymaster = dup(ptyfd)) < 0) {
676 error("%s: dup #2: %s", __func__, strerror(errno));
683 /* Fork the child. */
684 switch ((pid = fork())) {
686 error("%s: fork: %.100s", __func__, strerror(errno));
698 /* Child. Reinitialize the log because the pid has changed. */
699 log_init(__progname, options.log_level,
700 options.log_facility, log_stderr);
701 /* Close the master side of the pseudo tty. */
704 /* Make the pseudo tty our controlling tty. */
705 pty_make_controlling_tty(&ttyfd, s->tty);
707 /* Redirect stdin/stdout/stderr from the pseudo tty. */
708 if (dup2(ttyfd, 0) < 0)
709 error("dup2 stdin: %s", strerror(errno));
710 if (dup2(ttyfd, 1) < 0)
711 error("dup2 stdout: %s", strerror(errno));
712 if (dup2(ttyfd, 2) < 0)
713 error("dup2 stderr: %s", strerror(errno));
715 /* Close the extra descriptor for the pseudo tty. */
718 /* record login, etc. similar to login(1) */
720 if (!(options.use_login && command == NULL)) {
722 cray_init_job(s->pw); /* set up cray jid and tmpdir */
724 do_login(s, command);
726 # ifdef LOGIN_NEEDS_UTMPX
732 * Do common processing for the child, such as execing
735 do_child(s, command);
742 signal(WJSIGNAL, cray_job_termination_handler);
746 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
751 /* Parent. Close the slave side of the pseudo tty. */
754 /* Enter interactive session. */
755 s->ptymaster = ptymaster;
756 packet_set_interactive(1);
758 session_set_fds(s, ptyfd, fdout, -1, 1);
760 server_loop(pid, ptyfd, fdout, -1);
761 /* server_loop _has_ closed ptyfd and fdout. */
766 #ifdef LOGIN_NEEDS_UTMPX
768 do_pre_login(Session *s)
771 struct sockaddr_storage from;
772 pid_t pid = getpid();
775 * Get IP address of client. If the connection is not a socket, let
776 * the address be 0.0.0.0.
778 memset(&from, 0, sizeof(from));
779 fromlen = sizeof(from);
780 if (packet_connection_is_on_socket()) {
781 if (getpeername(packet_get_connection_in(),
782 (struct sockaddr *)&from, &fromlen) < 0) {
783 debug("getpeername: %.100s", strerror(errno));
788 record_utmp_only(pid, s->tty, s->pw->pw_name,
789 get_remote_name_or_ip(utmp_len, options.use_dns),
790 (struct sockaddr *)&from, fromlen);
795 * This is called to fork and execute a command. If another command is
796 * to be forced, execute that instead.
799 do_exec(Session *s, const char *command)
803 if (options.adm_forced_command) {
804 original_command = command;
805 command = options.adm_forced_command;
806 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
807 s->is_subsystem = SUBSYSTEM_INT_SFTP;
808 else if (s->is_subsystem)
809 s->is_subsystem = SUBSYSTEM_EXT;
810 debug("Forced command (config) '%.900s'", command);
811 } else if (forced_command) {
812 original_command = command;
813 command = forced_command;
814 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
815 s->is_subsystem = SUBSYSTEM_INT_SFTP;
816 else if (s->is_subsystem)
817 s->is_subsystem = SUBSYSTEM_EXT;
818 debug("Forced command (key option) '%.900s'", command);
821 #if defined(SESSION_HOOKS)
822 if (options.session_hooks_allow &&
823 (options.session_hooks_startup_cmd ||
824 options.session_hooks_shutdown_cmd))
832 "/tmp/ssh_env_%d%d%d",
836 } while (stat(env_file, &st)==0);
837 s->authctxt->session_env_file = strdup(env_file);
841 #ifdef SSH_AUDIT_EVENTS
843 PRIVSEP(audit_run_command(command));
844 else if (s->ttyfd == -1) {
845 char *shell = s->pw->pw_shell;
847 if (shell[0] == '\0') /* empty shell means /bin/sh */
849 PRIVSEP(audit_run_command(shell));
853 ret = do_exec_pty(s, command);
855 ret = do_exec_no_pty(s, command);
857 original_command = NULL;
860 * Clear loginmsg: it's the child's responsibility to display
861 * it to the user, otherwise multiple sessions may accumulate
862 * multiple copies of the login messages.
864 buffer_clear(&loginmsg);
869 /* administrative, login(1)-like work */
871 do_login(Session *s, const char *command)
874 struct sockaddr_storage from;
875 struct passwd * pw = s->pw;
876 pid_t pid = getpid();
879 * Get IP address of client. If the connection is not a socket, let
880 * the address be 0.0.0.0.
882 memset(&from, 0, sizeof(from));
883 fromlen = sizeof(from);
884 if (packet_connection_is_on_socket()) {
885 if (getpeername(packet_get_connection_in(),
886 (struct sockaddr *) & from, &fromlen) < 0) {
887 debug("getpeername: %.100s", strerror(errno));
892 /* Record that there was a login on that tty from the remote host. */
894 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
895 get_remote_name_or_ip(utmp_len,
897 (struct sockaddr *)&from, fromlen);
901 * If password change is needed, do it now.
902 * This needs to occur before the ~/.hushlogin check.
904 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
907 s->authctxt->force_pwchange = 0;
908 /* XXX - signal [net] parent to enable forwardings */
912 if (check_quietlogin(s, command))
921 * Display the message of the day.
929 if (options.print_motd) {
930 #ifdef HAVE_LOGIN_CAP
931 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
934 f = fopen("/etc/motd", "r");
937 while (fgets(buf, sizeof(buf), f))
946 * Check for quiet login, either .hushlogin or command given.
949 check_quietlogin(Session *s, const char *command)
952 struct passwd *pw = s->pw;
955 /* Return 1 if .hushlogin exists or a command given. */
958 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
959 #ifdef HAVE_LOGIN_CAP
960 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
963 if (stat(buf, &st) >= 0)
970 * Sets the value of the given variable in the environment. If the variable
971 * already exists, its value is overriden.
974 child_set_env(char ***envp, u_int *envsizep, const char *name,
982 * If we're passed an uninitialized list, allocate a single null
983 * entry before continuing.
985 if (*envp == NULL && *envsizep == 0) {
986 *envp = xmalloc(sizeof(char *));
992 * Find the slot where the value should be stored. If the variable
993 * already exists, we reuse the slot; otherwise we append a new slot
994 * at the end of the array, expanding if necessary.
997 namelen = strlen(name);
998 for (i = 0; env[i]; i++)
999 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1002 /* Reuse the slot. */
1005 /* New variable. Expand if necessary. */
1006 envsize = *envsizep;
1007 if (i >= envsize - 1) {
1008 if (envsize >= 1000)
1009 fatal("child_set_env: too many env vars");
1011 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1012 *envsizep = envsize;
1014 /* Need to set the NULL pointer at end of array beyond the new slot. */
1018 /* Allocate space and format the variable in the appropriate slot. */
1019 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1020 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1024 * Reads environment variables from the given file and adds/overrides them
1025 * into the environment. If the file does not exist, this does nothing.
1026 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1027 * and assignments of the form name=value. No other forms are allowed.
1030 read_environment_file(char ***env, u_int *envsize,
1031 const char *filename)
1038 f = fopen(filename, "r");
1042 while (fgets(buf, sizeof(buf), f)) {
1043 if (++lineno > 1000)
1044 fatal("Too many lines in environment file %s", filename);
1045 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1047 if (!*cp || *cp == '#' || *cp == '\n')
1050 cp[strcspn(cp, "\n")] = '\0';
1052 value = strchr(cp, '=');
1053 if (value == NULL) {
1054 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1059 * Replace the equals sign by nul, and advance value to
1064 child_set_env(env, envsize, cp, value);
1069 #ifdef SESSION_HOOKS
1070 #define SSH_SESSION_ENV_FILE "SSH_SESSION_ENV_FILE"
1072 typedef enum { no_op, execute, clear_env, restore_env,
1073 read_env, save_or_rm_env } session_action_t;
1075 static session_action_t action_order[2][5] = {
1076 { clear_env, read_env, execute, save_or_rm_env, restore_env }, /*shutdown*/
1077 { execute, read_env, save_or_rm_env, no_op, no_op } /*startup */
1081 void execute_session_hook(char* prog, Authctxt *authctxt,
1082 int startup, int save)
1084 extern char **environ;
1087 char **saved_env, **tmpenv;
1088 char *env_file = authctxt->session_env_file;
1093 switch (action_order[startup][i])
1106 authctxt->pw->pw_shell,
1109 debug("executing session hook: [%s]", buf);
1110 setenv(SSH_SESSION_ENV_FILE, env_file, /* overwrite = */ 1);
1112 /* flusing is recommended in the popen(3) man page, to avoid
1113 intermingling of output */
1116 if ((fp=popen(buf, "w")) == NULL)
1118 perror("Unable to run session hook");
1121 status = pclose(fp);
1122 debug2("session hook executed, status=%d", status);
1123 unsetenv(SSH_SESSION_ENV_FILE);
1128 saved_env = environ;
1129 tmpenv = (char**) malloc(sizeof(char*));
1135 environ = saved_env;
1140 if (status==0 && stat(env_file, &st)==0)
1144 debug("reading environment from %s", env_file);
1145 while (environ[envsize++]) ;
1146 read_environment_file(&environ, &envsize, env_file);
1150 case save_or_rm_env:
1151 if (status==0 && save)
1156 debug2("saving environment to %s", env_file);
1157 if ((fp = fopen(env_file, "w")) == NULL) /* hmm: file perms? */
1159 perror("Unable to save session hook info");
1161 while (environ[envcount])
1163 fprintf(fp, "%s\n", environ[envcount++]);
1168 else if (stat(env_file, &st)==0)
1170 debug2("removing environment file %s", env_file);
1180 #ifdef HAVE_ETC_DEFAULT_LOGIN
1182 * Return named variable from specified environment, or NULL if not present.
1185 child_get_env(char **env, const char *name)
1191 for (i=0; env[i] != NULL; i++)
1192 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1193 return(env[i] + len + 1);
1198 * Read /etc/default/login.
1199 * We pick up the PATH (or SUPATH for root) and UMASK.
1202 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1204 char **tmpenv = NULL, *var;
1205 u_int i, tmpenvsize = 0;
1209 * We don't want to copy the whole file to the child's environment,
1210 * so we use a temporary environment and copy the variables we're
1213 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1219 var = child_get_env(tmpenv, "SUPATH");
1221 var = child_get_env(tmpenv, "PATH");
1223 child_set_env(env, envsize, "PATH", var);
1225 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1226 if (sscanf(var, "%5lo", &mask) == 1)
1227 umask((mode_t)mask);
1229 for (i = 0; tmpenv[i] != NULL; i++)
1233 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1236 copy_environment(char **source, char ***env, u_int *envsize)
1238 char *var_name, *var_val;
1244 for(i = 0; source[i] != NULL; i++) {
1245 var_name = xstrdup(source[i]);
1246 if ((var_val = strstr(var_name, "=")) == NULL) {
1252 debug3("Copy environment: %s=%s", var_name, var_val);
1253 child_set_env(env, envsize, var_name, var_val);
1260 do_setup_env(Session *s, const char *shell)
1265 struct passwd *pw = s->pw;
1266 #ifndef HAVE_LOGIN_CAP
1270 /* Initialize the environment. */
1272 env = xcalloc(envsize, sizeof(char *));
1277 * The Windows environment contains some setting which are
1278 * important for a running system. They must not be dropped.
1283 p = fetch_windows_environment();
1284 copy_environment(p, &env, &envsize);
1285 free_windows_environment(p);
1290 /* Allow any GSSAPI methods that we've used to alter
1291 * the childs environment as they see fit
1293 ssh_gssapi_do_child(&env, &envsize);
1296 if (!options.use_login) {
1297 /* Set basic environment. */
1298 for (i = 0; i < s->num_env; i++)
1299 child_set_env(&env, &envsize, s->env[i].name,
1302 child_set_env(&env, &envsize, "USER", pw->pw_name);
1303 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1305 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1307 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1308 #ifdef HAVE_LOGIN_CAP
1309 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1310 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
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);
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);
1360 /* Set custom environment options from RSA authentication. */
1361 if (!options.use_login) {
1362 while (custom_environment) {
1363 struct envstring *ce = custom_environment;
1366 for (i = 0; str[i] != '=' && str[i]; i++)
1368 if (str[i] == '=') {
1370 child_set_env(&env, &envsize, str, str + i + 1);
1372 custom_environment = ce->next;
1378 /* SSH_CLIENT deprecated */
1379 snprintf(buf, sizeof buf, "%.50s %d %d",
1380 get_remote_ipaddr(), get_remote_port(), get_local_port());
1381 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1383 laddr = get_local_ipaddr(packet_get_connection_in());
1384 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1385 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1387 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1390 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1392 child_set_env(&env, &envsize, "TERM", s->term);
1394 child_set_env(&env, &envsize, "DISPLAY", s->display);
1395 if (original_command)
1396 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1400 if (cray_tmpdir[0] != '\0')
1401 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1402 #endif /* _UNICOS */
1405 * Since we clear KRB5CCNAME at startup, if it's set now then it
1406 * must have been set by a native authentication method (eg AIX or
1407 * SIA), so copy it to the child.
1412 if ((cp = getenv("KRB5CCNAME")) != NULL)
1413 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1420 if ((cp = getenv("AUTHSTATE")) != NULL)
1421 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1422 read_environment_file(&env, &envsize, "/etc/environment");
1426 if (s->authctxt->krb5_ccname)
1427 child_set_env(&env, &envsize, "KRB5CCNAME",
1428 s->authctxt->krb5_ccname);
1432 * Pull in any environment variables that may have
1435 if (options.use_pam) {
1438 p = fetch_pam_child_environment();
1439 copy_environment(p, &env, &envsize);
1440 free_pam_environment(p);
1442 p = fetch_pam_environment();
1443 copy_environment(p, &env, &envsize);
1444 free_pam_environment(p);
1446 #endif /* USE_PAM */
1448 if (auth_sock_name != NULL)
1449 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1452 /* read $HOME/.ssh/environment. */
1453 if (options.permit_user_env && !options.use_login) {
1454 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1455 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1456 read_environment_file(&env, &envsize, buf);
1459 /* dump the environment */
1460 fprintf(stderr, "Environment:\n");
1461 for (i = 0; env[i]; i++)
1462 fprintf(stderr, " %.200s\n", env[i]);
1468 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1469 * first in this order).
1472 do_rc_files(Session *s, const char *shell)
1480 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1482 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1483 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1484 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1485 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1486 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1488 fprintf(stderr, "Running %s\n", cmd);
1489 f = popen(cmd, "w");
1492 fprintf(f, "%s %s\n", s->auth_proto,
1496 fprintf(stderr, "Could not run %s\n",
1498 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1500 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1501 _PATH_SSH_SYSTEM_RC);
1502 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1505 fprintf(f, "%s %s\n", s->auth_proto,
1509 fprintf(stderr, "Could not run %s\n",
1510 _PATH_SSH_SYSTEM_RC);
1511 } else if (do_xauth && options.xauth_location != NULL) {
1512 /* Add authority data to .Xauthority if appropriate. */
1515 "Running %.500s remove %.100s\n",
1516 options.xauth_location, s->auth_display);
1518 "%.500s add %.100s %.100s %.100s\n",
1519 options.xauth_location, s->auth_display,
1520 s->auth_proto, s->auth_data);
1522 snprintf(cmd, sizeof cmd, "%s -q -",
1523 options.xauth_location);
1524 f = popen(cmd, "w");
1526 fprintf(f, "remove %s\n",
1528 fprintf(f, "add %s %s %s\n",
1529 s->auth_display, s->auth_proto,
1533 fprintf(stderr, "Could not run %s\n",
1540 do_nologin(struct passwd *pw)
1545 #ifdef HAVE_LOGIN_CAP
1546 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1547 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1548 _PATH_NOLOGIN), "r");
1551 f = fopen(_PATH_NOLOGIN, "r");
1554 /* /etc/nologin exists. Print its contents and exit. */
1555 logit("User %.100s not allowed because %s exists",
1556 pw->pw_name, _PATH_NOLOGIN);
1557 while (fgets(buf, sizeof(buf), f))
1566 * Chroot into a directory after checking it for safety: all path components
1567 * must be root-owned directories with strict permissions.
1570 safely_chroot(const char *path, uid_t uid)
1573 char component[MAXPATHLEN];
1577 fatal("chroot path does not begin at root");
1578 if (strlen(path) >= sizeof(component))
1579 fatal("chroot path too long");
1582 * Descend the path, checking that each component is a
1583 * root-owned directory with strict permissions.
1585 for (cp = path; cp != NULL;) {
1586 if ((cp = strchr(cp, '/')) == NULL)
1587 strlcpy(component, path, sizeof(component));
1590 memcpy(component, path, cp - path);
1591 component[cp - path] = '\0';
1594 debug3("%s: checking '%s'", __func__, component);
1596 if (stat(component, &st) != 0)
1597 fatal("%s: stat(\"%s\"): %s", __func__,
1598 component, strerror(errno));
1599 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1600 fatal("bad ownership or modes for chroot "
1601 "directory %s\"%s\"",
1602 cp == NULL ? "" : "component ", component);
1603 if (!S_ISDIR(st.st_mode))
1604 fatal("chroot path %s\"%s\" is not a directory",
1605 cp == NULL ? "" : "component ", component);
1609 if (chdir(path) == -1)
1610 fatal("Unable to chdir to chroot path \"%s\": "
1611 "%s", path, strerror(errno));
1612 if (chroot(path) == -1)
1613 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1614 if (chdir("/") == -1)
1615 fatal("%s: chdir(/) after chroot: %s",
1616 __func__, strerror(errno));
1617 verbose("Changed root directory to \"%s\"", path);
1620 /* Set login name, uid, gid, and groups. */
1622 do_setusercontext(struct passwd *pw)
1624 char *chroot_path, *tmp;
1627 /* Cache selinux status for later use */
1628 (void)ssh_selinux_enabled();
1632 if (getuid() == 0 || geteuid() == 0)
1633 #endif /* HAVE_CYGWIN */
1636 #ifdef HAVE_SETPCRED
1637 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1638 fatal("Failed to set process credentials");
1639 #endif /* HAVE_SETPCRED */
1640 #ifdef HAVE_LOGIN_CAP
1645 if (options.use_pam) {
1646 do_pam_setcred(use_privsep);
1648 # endif /* USE_PAM */
1649 if (setusercontext(lc, pw, pw->pw_uid,
1650 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1651 perror("unable to set user context");
1655 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1656 /* Sets login uid for accounting */
1657 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1658 error("setluid: %s", strerror(errno));
1659 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1661 if (setlogin(pw->pw_name) < 0)
1662 error("setlogin failed: %s", strerror(errno));
1663 if (setgid(pw->pw_gid) < 0) {
1667 /* Initialize the group list. */
1668 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1669 perror("initgroups");
1675 * PAM credentials may take the form of supplementary groups.
1676 * These will have been wiped by the above initgroups() call.
1677 * Reestablish them here.
1679 if (options.use_pam) {
1680 do_pam_setcred(use_privsep);
1682 # endif /* USE_PAM */
1683 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1684 irix_setusercontext(pw);
1685 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1690 if (set_id(pw->pw_name) != 0) {
1693 # endif /* USE_LIBIAF */
1696 if (options.chroot_directory != NULL &&
1697 strcasecmp(options.chroot_directory, "none") != 0) {
1698 tmp = tilde_expand_filename(options.chroot_directory,
1700 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1701 "u", pw->pw_name, (char *)NULL);
1702 safely_chroot(chroot_path, pw->pw_uid);
1707 #ifdef HAVE_LOGIN_CAP
1708 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1709 perror("unable to set user context (setuser)");
1713 /* Permanently switch to the desired uid. */
1714 permanently_set_uid(pw);
1721 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1722 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1725 ssh_selinux_setup_exec_context(pw->pw_name);
1730 do_pwchange(Session *s)
1733 fprintf(stderr, "WARNING: Your password has expired.\n");
1734 if (s->ttyfd != -1) {
1736 "You must change your password now and login again!\n");
1737 #ifdef PASSWD_NEEDS_USERNAME
1738 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1741 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1746 "Password change required but no TTY available.\n");
1752 launch_login(struct passwd *pw, const char *hostname)
1754 /* Launch login(1). */
1756 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1757 #ifdef xxxLOGIN_NEEDS_TERM
1758 (s->term ? s->term : "unknown"),
1759 #endif /* LOGIN_NEEDS_TERM */
1760 #ifdef LOGIN_NO_ENDOPT
1761 "-p", "-f", pw->pw_name, (char *)NULL);
1763 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1766 /* Login couldn't be executed, die. */
1773 child_close_fds(void)
1777 if (packet_get_connection_in() == packet_get_connection_out())
1778 close(packet_get_connection_in());
1780 close(packet_get_connection_in());
1781 close(packet_get_connection_out());
1784 * Close all descriptors related to channels. They will still remain
1785 * open in the parent.
1787 /* XXX better use close-on-exec? -markus */
1788 channel_close_all();
1791 * Close any extra file descriptors. Note that there may still be
1792 * descriptors left by system functions. They will be closed later.
1797 * Close any extra open file descriptors so that we don't have them
1798 * hanging around in clients. Note that we want to do this after
1799 * initgroups, because at least on Solaris 2.3 it leaves file
1802 for (i = 3; i < 64; i++)
1807 * Performs common processing for the child, such as setting up the
1808 * environment, closing extra file descriptors, setting the user and group
1809 * ids, and executing the command or shell.
1813 do_child(Session *s, const char *command)
1815 extern char **environ;
1817 char *argv[ARGV_MAX];
1818 const char *shell, *shell0, *hostname = NULL;
1819 struct passwd *pw = s->pw;
1823 /* Default place to look for aklog. */
1825 #define KPROGDIR AKLOG_PATH
1827 #define KPROGDIR "/usr/bin/aklog"
1828 #endif /* AKLOG_PATH */
1832 #endif /* AFS_KRB5 */
1834 /* remove hostkey from the child's memory */
1835 destroy_sensitive_data();
1837 /* Force a password change */
1838 if (s->authctxt->force_pwchange) {
1839 do_setusercontext(pw);
1845 /* login(1) is only called if we execute the login shell */
1846 if (options.use_login && command != NULL)
1847 options.use_login = 0;
1850 cray_setup(pw->pw_uid, pw->pw_name, command);
1851 #endif /* _UNICOS */
1854 * Login(1) does this as well, and it needs uid 0 for the "-h"
1855 * switch, so we let login(1) to this for us.
1857 if (!options.use_login) {
1859 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1860 if (!check_quietlogin(s, command))
1862 #else /* HAVE_OSF_SIA */
1863 /* When PAM is enabled we rely on it to do the nologin check */
1864 if (!options.use_pam)
1866 do_setusercontext(pw);
1868 * PAM session modules in do_setusercontext may have
1869 * generated messages, so if this in an interactive
1870 * login then display them too.
1872 if (!check_quietlogin(s, command))
1874 #endif /* HAVE_OSF_SIA */
1878 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1879 debug3("PAM session not opened, exiting");
1886 * Get the shell from the password data. An empty shell field is
1887 * legal, and means /bin/sh.
1889 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1892 * Make sure $SHELL points to the shell from the password file,
1893 * even if shell is overridden from login.conf
1895 env = do_setup_env(s, shell);
1897 #ifdef HAVE_LOGIN_CAP
1898 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1901 /* we have to stash the hostname before we close our socket. */
1902 if (options.use_login)
1903 hostname = get_remote_name_or_ip(utmp_len,
1906 * Close the connection descriptors; note that this is the child, and
1907 * the server will still have the socket open, and it is important
1908 * that we do not shutdown it. Note that the descriptors cannot be
1909 * closed before building the environment, as we call
1910 * get_remote_ipaddr there.
1915 * Must take new environment into use so that .ssh/rc,
1916 * /etc/ssh/sshrc and xauth are run in the proper environment.
1920 #if defined(KRB5) && defined(USE_AFS)
1922 * At this point, we check to see if AFS is active and if we have
1923 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1924 * if we can (and need to) extend the ticket into an AFS token. If
1925 * we don't do this, we run into potential problems if the user's
1926 * home directory is in AFS and it's not world-readable.
1929 if (options.kerberos_get_afs_token && k_hasafs() &&
1930 (s->authctxt->krb5_ctx != NULL)) {
1933 debug("Getting AFS token");
1937 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1938 krb5_afslog(s->authctxt->krb5_ctx,
1939 s->authctxt->krb5_fwd_ccache, cell, NULL);
1941 krb5_afslog_home(s->authctxt->krb5_ctx,
1942 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1948 /* User has authenticated, and if a ticket was going to be
1949 * passed we would have it. KRB5CCNAME should already be set.
1950 * Now try to get an AFS token using aklog.
1952 if (k_hasafs()) { /* Do we have AFS? */
1954 aklog_path = xstrdup(KPROGDIR);
1957 * Make sure it exists before we try to run it
1959 if (stat(aklog_path, &st) == 0) {
1960 debug("Running %s to get afs token.",aklog_path);
1963 debug("%s does not exist.",aklog_path);
1968 #endif /* AFS_KRB5 */
1970 #ifdef SESSION_HOOKS
1971 if (options.session_hooks_allow &&
1972 options.session_hooks_startup_cmd)
1974 execute_session_hook(options.session_hooks_startup_cmd,
1977 options.session_hooks_shutdown_cmd != NULL);
1981 /* Change current directory to the user's home directory. */
1982 if (chdir(pw->pw_dir) < 0) {
1983 /* Suppress missing homedir warning for chroot case */
1984 #ifdef HAVE_LOGIN_CAP
1985 r = login_getcapbool(lc, "requirehome", 0);
1987 if (r || options.chroot_directory == NULL)
1988 fprintf(stderr, "Could not chdir to home "
1989 "directory %s: %s\n", pw->pw_dir,
1995 closefrom(STDERR_FILENO + 1);
1997 if (!options.use_login)
1998 do_rc_files(s, shell);
2000 /* restore SIGPIPE for child */
2001 signal(SIGPIPE, SIG_DFL);
2003 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
2004 extern int optind, optreset;
2008 setproctitle("%s@internal-sftp-server", s->pw->pw_name);
2009 args = strdup(command ? command : "sftp-server");
2010 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
2011 if (i < ARGV_MAX - 1)
2014 optind = optreset = 1;
2015 __progname = argv[0];
2016 exit(sftp_server_main(i, argv, s->pw));
2019 if (options.use_login) {
2020 launch_login(pw, hostname);
2024 /* Get the last component of the shell name. */
2025 if ((shell0 = strrchr(shell, '/')) != NULL)
2031 * If we have no command, execute the shell. In this case, the shell
2032 * name to be passed in argv[0] is preceded by '-' to indicate that
2033 * this is a login shell.
2038 /* Start the shell. Set initial character to '-'. */
2041 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
2042 >= sizeof(argv0) - 1) {
2048 /* Execute the shell. */
2051 execve(shell, argv, environ);
2053 /* Executing the shell failed. */
2058 * Execute the command using the user's shell. This uses the -c
2059 * option to execute the command.
2061 argv[0] = (char *) shell0;
2063 argv[2] = (char *) command;
2065 execve(shell, argv, environ);
2071 session_unused(int id)
2073 debug3("%s: session id %d unused", __func__, id);
2074 if (id >= options.max_sessions ||
2075 id >= sessions_nalloc) {
2076 fatal("%s: insane session id %d (max %d nalloc %d)",
2077 __func__, id, options.max_sessions, sessions_nalloc);
2079 bzero(&sessions[id], sizeof(*sessions));
2080 sessions[id].self = id;
2081 sessions[id].used = 0;
2082 sessions[id].chanid = -1;
2083 sessions[id].ptyfd = -1;
2084 sessions[id].ttyfd = -1;
2085 sessions[id].ptymaster = -1;
2086 sessions[id].x11_chanids = NULL;
2087 sessions[id].next_unused = sessions_first_unused;
2088 sessions_first_unused = id;
2096 if (sessions_first_unused == -1) {
2097 if (sessions_nalloc >= options.max_sessions)
2099 debug2("%s: allocate (allocated %d max %d)",
2100 __func__, sessions_nalloc, options.max_sessions);
2101 tmp = xrealloc(sessions, sessions_nalloc + 1,
2104 error("%s: cannot allocate %d sessions",
2105 __func__, sessions_nalloc + 1);
2109 session_unused(sessions_nalloc++);
2112 if (sessions_first_unused >= sessions_nalloc ||
2113 sessions_first_unused < 0) {
2114 fatal("%s: insane first_unused %d max %d nalloc %d",
2115 __func__, sessions_first_unused, options.max_sessions,
2119 s = &sessions[sessions_first_unused];
2121 fatal("%s: session %d already used",
2122 __func__, sessions_first_unused);
2124 sessions_first_unused = s->next_unused;
2126 s->next_unused = -1;
2127 debug("session_new: session %d", s->self);
2136 for (i = 0; i < sessions_nalloc; i++) {
2137 Session *s = &sessions[i];
2139 debug("dump: used %d next_unused %d session %d %p "
2140 "channel %d pid %ld",
2151 session_open(Authctxt *authctxt, int chanid)
2153 Session *s = session_new();
2154 debug("session_open: channel %d", chanid);
2156 error("no more sessions");
2159 s->authctxt = authctxt;
2160 s->pw = authctxt->pw;
2161 if (s->pw == NULL || !authctxt->valid)
2162 fatal("no user for session %d", s->self);
2163 debug("session_open: session %d: link with channel %d", s->self, chanid);
2169 session_by_tty(char *tty)
2172 for (i = 0; i < sessions_nalloc; i++) {
2173 Session *s = &sessions[i];
2174 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2175 debug("session_by_tty: session %d tty %s", i, tty);
2179 debug("session_by_tty: unknown tty %.100s", tty);
2185 session_by_channel(int id)
2188 for (i = 0; i < sessions_nalloc; i++) {
2189 Session *s = &sessions[i];
2190 if (s->used && s->chanid == id) {
2191 debug("session_by_channel: session %d channel %d",
2196 debug("session_by_channel: unknown channel %d", id);
2202 session_by_x11_channel(int id)
2206 for (i = 0; i < sessions_nalloc; i++) {
2207 Session *s = &sessions[i];
2209 if (s->x11_chanids == NULL || !s->used)
2211 for (j = 0; s->x11_chanids[j] != -1; j++) {
2212 if (s->x11_chanids[j] == id) {
2213 debug("session_by_x11_channel: session %d "
2214 "channel %d", s->self, id);
2219 debug("session_by_x11_channel: unknown channel %d", id);
2225 session_by_pid(pid_t pid)
2228 debug("session_by_pid: pid %ld", (long)pid);
2229 for (i = 0; i < sessions_nalloc; i++) {
2230 Session *s = &sessions[i];
2231 if (s->used && s->pid == pid)
2234 error("session_by_pid: unknown pid %ld", (long)pid);
2240 session_window_change_req(Session *s)
2242 s->col = packet_get_int();
2243 s->row = packet_get_int();
2244 s->xpixel = packet_get_int();
2245 s->ypixel = packet_get_int();
2247 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2252 session_pty_req(Session *s)
2258 debug("Allocating a pty not permitted for this authentication.");
2261 if (s->ttyfd != -1) {
2262 packet_disconnect("Protocol error: you already have a pty.");
2266 s->term = packet_get_string(&len);
2269 s->col = packet_get_int();
2270 s->row = packet_get_int();
2272 s->row = packet_get_int();
2273 s->col = packet_get_int();
2275 s->xpixel = packet_get_int();
2276 s->ypixel = packet_get_int();
2278 if (strcmp(s->term, "") == 0) {
2283 /* Allocate a pty and open it. */
2284 debug("Allocating pty.");
2285 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2292 error("session_pty_req: session %d alloc failed", s->self);
2295 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2297 /* for SSH1 the tty modes length is not given */
2299 n_bytes = packet_remaining();
2300 tty_parse_modes(s->ttyfd, &n_bytes);
2303 pty_setowner(s->pw, s->tty);
2305 /* Set window size from the packet. */
2306 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2309 session_proctitle(s);
2314 session_subsystem_req(Session *s)
2319 char *prog, *cmd, *subsys = packet_get_string(&len);
2323 logit("subsystem request for %.100s", subsys);
2325 for (i = 0; i < options.num_subsystems; i++) {
2326 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2327 prog = options.subsystem_command[i];
2328 cmd = options.subsystem_args[i];
2329 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
2330 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2331 } else if (stat(prog, &st) < 0) {
2332 error("subsystem: cannot stat %s: %s", prog,
2336 s->is_subsystem = SUBSYSTEM_EXT;
2338 debug("subsystem: exec() %s", cmd);
2339 success = do_exec(s, cmd) == 0;
2345 logit("subsystem request for %.100s failed, subsystem not found",
2353 session_x11_req(Session *s)
2357 if (s->auth_proto != NULL || s->auth_data != NULL) {
2358 error("session_x11_req: session %d: "
2359 "x11 forwarding already active", s->self);
2362 s->single_connection = packet_get_char();
2363 s->auth_proto = packet_get_string(NULL);
2364 s->auth_data = packet_get_string(NULL);
2365 s->screen = packet_get_int();
2368 success = session_setup_x11fwd(s);
2370 xfree(s->auth_proto);
2371 xfree(s->auth_data);
2372 s->auth_proto = NULL;
2373 s->auth_data = NULL;
2379 session_shell_req(Session *s)
2382 return do_exec(s, NULL) == 0;
2386 session_exec_req(Session *s)
2390 char *command = packet_get_string(&len);
2392 success = do_exec(s, command) == 0;
2398 session_break_req(Session *s)
2401 packet_get_int(); /* ignored */
2404 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
2410 session_env_req(Session *s)
2413 u_int name_len, val_len, i;
2415 name = packet_get_string(&name_len);
2416 val = packet_get_string(&val_len);
2419 /* Don't set too many environment variables */
2420 if (s->num_env > 128) {
2421 debug2("Ignoring env request %s: too many env vars", name);
2425 for (i = 0; i < options.num_accept_env; i++) {
2426 if (match_pattern(name, options.accept_env[i])) {
2427 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2428 s->env = xrealloc(s->env, s->num_env + 1,
2430 s->env[s->num_env].name = name;
2431 s->env[s->num_env].val = val;
2436 debug2("Ignoring env request %s: disallowed name", name);
2445 session_auth_agent_req(Session *s)
2447 static int called = 0;
2449 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2450 debug("session_auth_agent_req: no_agent_forwarding_flag");
2457 return auth_input_request_forwarding(s->pw);
2462 session_input_channel_req(Channel *c, const char *rtype)
2467 if ((s = session_by_channel(c->self)) == NULL) {
2468 logit("session_input_channel_req: no session %d req %.100s",
2472 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2475 * a session is in LARVAL state until a shell, a command
2476 * or a subsystem is executed
2478 if (c->type == SSH_CHANNEL_LARVAL) {
2479 if (strcmp(rtype, "shell") == 0) {
2480 success = session_shell_req(s);
2481 } else if (strcmp(rtype, "exec") == 0) {
2482 success = session_exec_req(s);
2483 } else if (strcmp(rtype, "pty-req") == 0) {
2484 success = session_pty_req(s);
2485 } else if (strcmp(rtype, "x11-req") == 0) {
2486 success = session_x11_req(s);
2487 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2488 success = session_auth_agent_req(s);
2489 } else if (strcmp(rtype, "subsystem") == 0) {
2490 success = session_subsystem_req(s);
2491 } else if (strcmp(rtype, "env") == 0) {
2492 success = session_env_req(s);
2495 if (strcmp(rtype, "window-change") == 0) {
2496 success = session_window_change_req(s);
2497 } else if (strcmp(rtype, "break") == 0) {
2498 success = session_break_req(s);
2505 session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
2508 fatal("session_set_fds: called for proto != 2.0");
2510 * now that have a child and a pipe to the child,
2511 * we can activate our channel and register the fd's
2513 if (s->chanid == -1)
2514 fatal("no channel for session %d", s->self);
2515 channel_set_fds(s->chanid,
2517 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2518 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2522 * Function to perform pty cleanup. Also called if we get aborted abnormally
2523 * (e.g., due to a dropped connection).
2526 session_pty_cleanup2(Session *s)
2529 error("session_pty_cleanup: no session");
2535 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2537 /* Record that the user has logged out. */
2539 record_logout(s->pid, s->tty, s->pw->pw_name);
2541 /* Release the pseudo-tty. */
2543 pty_release(s->tty);
2546 * Close the server side of the socket pairs. We must do this after
2547 * the pty cleanup, so that another process doesn't get this pty
2548 * while we're still cleaning up.
2550 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2551 error("close(s->ptymaster/%d): %s",
2552 s->ptymaster, strerror(errno));
2554 /* unlink pty from session */
2559 session_pty_cleanup(Session *s)
2561 PRIVSEP(session_pty_cleanup2(s));
2567 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2582 return "SIG@openssh.com";
2586 session_close_x11(int id)
2590 if ((c = channel_by_id(id)) == NULL) {
2591 debug("session_close_x11: x11 channel %d missing", id);
2593 /* Detach X11 listener */
2594 debug("session_close_x11: detach x11 channel %d", id);
2595 channel_cancel_cleanup(id);
2596 if (c->ostate != CHAN_OUTPUT_CLOSED)
2602 session_close_single_x11(int id, void *arg)
2607 debug3("session_close_single_x11: channel %d", id);
2608 channel_cancel_cleanup(id);
2609 if ((s = session_by_x11_channel(id)) == NULL)
2610 fatal("session_close_single_x11: no x11 channel %d", id);
2611 for (i = 0; s->x11_chanids[i] != -1; i++) {
2612 debug("session_close_single_x11: session %d: "
2613 "closing channel %d", s->self, s->x11_chanids[i]);
2615 * The channel "id" is already closing, but make sure we
2616 * close all of its siblings.
2618 if (s->x11_chanids[i] != id)
2619 session_close_x11(s->x11_chanids[i]);
2621 xfree(s->x11_chanids);
2622 s->x11_chanids = NULL;
2627 if (s->auth_proto) {
2628 xfree(s->auth_proto);
2629 s->auth_proto = NULL;
2632 xfree(s->auth_data);
2633 s->auth_data = NULL;
2635 if (s->auth_display) {
2636 xfree(s->auth_display);
2637 s->auth_display = NULL;
2642 session_exit_message(Session *s, int status)
2646 if ((c = channel_lookup(s->chanid)) == NULL)
2647 fatal("session_exit_message: session %d: no channel %d",
2648 s->self, s->chanid);
2649 debug("session_exit_message: session %d channel %d pid %ld",
2650 s->self, s->chanid, (long)s->pid);
2652 if (WIFEXITED(status)) {
2653 channel_request_start(s->chanid, "exit-status", 0);
2654 packet_put_int(WEXITSTATUS(status));
2656 } else if (WIFSIGNALED(status)) {
2657 channel_request_start(s->chanid, "exit-signal", 0);
2658 packet_put_cstring(sig2name(WTERMSIG(status)));
2660 packet_put_char(WCOREDUMP(status)? 1 : 0);
2661 #else /* WCOREDUMP */
2663 #endif /* WCOREDUMP */
2664 packet_put_cstring("");
2665 packet_put_cstring("");
2668 /* Some weird exit cause. Just exit. */
2669 packet_disconnect("wait returned status %04x.", status);
2672 /* disconnect channel */
2673 debug("session_exit_message: release channel %d", s->chanid);
2676 * Adjust cleanup callback attachment to send close messages when
2677 * the channel gets EOF. The session will be then be closed
2678 * by session_close_by_channel when the childs close their fds.
2680 channel_register_cleanup(c->self, session_close_by_channel, 1);
2683 * emulate a write failure with 'chan_write_failed', nobody will be
2684 * interested in data we write.
2685 * Note that we must not call 'chan_read_failed', since there could
2686 * be some more data waiting in the pipe.
2688 if (c->ostate != CHAN_OUTPUT_CLOSED)
2689 chan_write_failed(c);
2693 session_close(Session *s)
2697 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2699 session_pty_cleanup(s);
2705 xfree(s->x11_chanids);
2706 if (s->auth_display)
2707 xfree(s->auth_display);
2709 xfree(s->auth_data);
2711 xfree(s->auth_proto);
2712 if (s->env != NULL) {
2713 for (i = 0; i < s->num_env; i++) {
2714 xfree(s->env[i].name);
2715 xfree(s->env[i].val);
2719 session_proctitle(s);
2720 session_unused(s->self);
2724 session_close_by_pid(pid_t pid, int status)
2726 Session *s = session_by_pid(pid);
2728 debug("session_close_by_pid: no session for pid %ld",
2732 if (s->chanid != -1)
2733 session_exit_message(s, status);
2735 session_pty_cleanup(s);
2740 * this is called when a channel dies before
2741 * the session 'child' itself dies
2744 session_close_by_channel(int id, void *arg)
2746 Session *s = session_by_channel(id);
2750 debug("session_close_by_channel: no session for id %d", id);
2753 debug("session_close_by_channel: channel %d child %ld",
2756 debug("session_close_by_channel: channel %d: has child", id);
2758 * delay detach of session, but release pty, since
2759 * the fd's to the child are already closed
2762 session_pty_cleanup(s);
2765 /* detach by removing callback */
2766 channel_cancel_cleanup(s->chanid);
2768 /* Close any X11 listeners associated with this session */
2769 if (s->x11_chanids != NULL) {
2770 for (i = 0; s->x11_chanids[i] != -1; i++) {
2771 session_close_x11(s->x11_chanids[i]);
2772 s->x11_chanids[i] = -1;
2781 session_destroy_all(void (*closefunc)(Session *))
2784 for (i = 0; i < sessions_nalloc; i++) {
2785 Session *s = &sessions[i];
2787 if (closefunc != NULL)
2796 session_tty_list(void)
2798 static char buf[1024];
2803 for (i = 0; i < sessions_nalloc; i++) {
2804 Session *s = &sessions[i];
2805 if (s->used && s->ttyfd != -1) {
2807 if (strncmp(s->tty, "/dev/", 5) != 0) {
2808 cp = strrchr(s->tty, '/');
2809 cp = (cp == NULL) ? s->tty : cp + 1;
2814 strlcat(buf, ",", sizeof buf);
2815 strlcat(buf, cp, sizeof buf);
2819 strlcpy(buf, "notty", sizeof buf);
2824 session_proctitle(Session *s)
2827 error("no user for session %d", s->self);
2829 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2833 session_setup_x11fwd(Session *s)
2836 char display[512], auth_display[512];
2837 char hostname[MAXHOSTNAMELEN];
2840 if (no_x11_forwarding_flag) {
2841 packet_send_debug("X11 forwarding disabled in user configuration file.");
2844 if (!options.x11_forwarding) {
2845 debug("X11 forwarding disabled in server configuration file.");
2848 if (!options.xauth_location ||
2849 (stat(options.xauth_location, &st) == -1)) {
2850 packet_send_debug("No xauth program; cannot forward with spoofing.");
2853 if (options.use_login) {
2854 packet_send_debug("X11 forwarding disabled; "
2855 "not compatible with UseLogin=yes.");
2858 if (s->display != NULL) {
2859 debug("X11 display already set.");
2862 if (x11_create_display_inet(options.x11_display_offset,
2863 options.x11_use_localhost, s->single_connection,
2864 &s->display_number, &s->x11_chanids,
2865 options.hpn_disabled, options.hpn_buffer_size) == -1) {
2866 debug("x11_create_display_inet failed.");
2869 for (i = 0; s->x11_chanids[i] != -1; i++) {
2870 channel_register_cleanup(s->x11_chanids[i],
2871 session_close_single_x11, 0);
2874 /* Set up a suitable value for the DISPLAY variable. */
2875 if (gethostname(hostname, sizeof(hostname)) < 0)
2876 fatal("gethostname: %.100s", strerror(errno));
2878 * auth_display must be used as the displayname when the
2879 * authorization entry is added with xauth(1). This will be
2880 * different than the DISPLAY string for localhost displays.
2882 if (options.x11_use_localhost) {
2883 snprintf(display, sizeof display, "localhost:%u.%u",
2884 s->display_number, s->screen);
2885 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2886 s->display_number, s->screen);
2887 s->display = xstrdup(display);
2888 s->auth_display = xstrdup(auth_display);
2890 #ifdef IPADDR_IN_DISPLAY
2892 struct in_addr my_addr;
2894 he = gethostbyname(hostname);
2896 error("Can't get IP address for X11 DISPLAY.");
2897 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2900 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2901 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2902 s->display_number, s->screen);
2904 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2905 s->display_number, s->screen);
2907 s->display = xstrdup(display);
2908 s->auth_display = xstrdup(display);
2915 do_authenticated2(Authctxt *authctxt)
2917 server_loop2(authctxt);
2921 do_cleanup(Authctxt *authctxt)
2923 static int called = 0;
2925 debug("do_cleanup");
2927 /* no cleanup if we're in the child for login shell */
2931 /* avoid double cleanup */
2936 if (authctxt == NULL)
2940 if (options.use_pam) {
2942 sshpam_thread_cleanup();
2946 if (!authctxt->authenticated)
2950 if (options.kerberos_ticket_cleanup &&
2952 krb5_cleanup_proc(authctxt);
2956 if (compat20 && options.gss_cleanup_creds)
2957 ssh_gssapi_cleanup_creds();
2960 /* remove agent socket */
2961 auth_sock_cleanup_proc(authctxt->pw);
2964 * Cleanup ptys/utmp only if privsep is disabled,
2965 * or if running in monitor.
2967 if (!use_privsep || mm_is_monitor())
2968 session_destroy_all(session_pty_cleanup2);