1 /* $OpenBSD: session.c,v 1.235 2008/05/07 05:49:37 pyr 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>
80 #include "auth-options.h"
81 #include "pathnames.h"
85 #include "serverloop.h"
90 #include "monitor_wrap.h"
93 #if defined(KRB5) && defined(USE_AFS)
99 Session *session_new(void);
100 void session_set_fds(Session *, int, int, int);
101 void session_pty_cleanup(Session *);
102 void session_proctitle(Session *);
103 int session_setup_x11fwd(Session *);
104 void do_exec_pty(Session *, const char *);
105 void do_exec_no_pty(Session *, const char *);
106 void do_exec(Session *, const char *);
107 void do_login(Session *, const char *);
108 #ifdef LOGIN_NEEDS_UTMPX
109 static void do_pre_login(Session *s);
111 void do_child(Session *, const char *);
113 int check_quietlogin(Session *, const char *);
115 static void do_authenticated1(Authctxt *);
116 static void do_authenticated2(Authctxt *);
118 static int session_pty_req(Session *);
121 extern ServerOptions options;
122 extern char *__progname;
123 extern int log_stderr;
124 extern int debug_flag;
125 extern u_int utmp_len;
126 extern int startup_pipe;
127 extern void destroy_sensitive_data(void);
128 extern Buffer loginmsg;
130 /* original command from peer. */
131 const char *original_command = NULL;
134 #define MAX_SESSIONS 20
135 Session sessions[MAX_SESSIONS];
137 #define SUBSYSTEM_NONE 0
138 #define SUBSYSTEM_EXT 1
139 #define SUBSYSTEM_INT_SFTP 2
141 #ifdef HAVE_LOGIN_CAP
145 static int is_child = 0;
147 /* Name and directory of socket for authentication agent forwarding. */
148 static char *auth_sock_name = NULL;
149 static char *auth_sock_dir = NULL;
151 /* removes the agent forwarding socket */
154 auth_sock_cleanup_proc(struct passwd *pw)
156 if (auth_sock_name != NULL) {
157 temporarily_use_uid(pw);
158 unlink(auth_sock_name);
159 rmdir(auth_sock_dir);
160 auth_sock_name = NULL;
166 auth_input_request_forwarding(struct passwd * pw)
170 struct sockaddr_un sunaddr;
172 if (auth_sock_name != NULL) {
173 error("authentication forwarding requested twice.");
177 /* Temporarily drop privileged uid for mkdir/bind. */
178 temporarily_use_uid(pw);
180 /* Allocate a buffer for the socket name, and format the name. */
181 auth_sock_name = xmalloc(MAXPATHLEN);
182 auth_sock_dir = xmalloc(MAXPATHLEN);
183 strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN);
185 /* Create private directory for socket */
186 if (mkdtemp(auth_sock_dir) == NULL) {
187 packet_send_debug("Agent forwarding disabled: "
188 "mkdtemp() failed: %.100s", strerror(errno));
190 xfree(auth_sock_name);
191 xfree(auth_sock_dir);
192 auth_sock_name = NULL;
193 auth_sock_dir = NULL;
196 snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%ld",
197 auth_sock_dir, (long) getpid());
199 /* Create the socket. */
200 sock = socket(AF_UNIX, SOCK_STREAM, 0);
202 packet_disconnect("socket: %.100s", strerror(errno));
204 /* Bind it to the name. */
205 memset(&sunaddr, 0, sizeof(sunaddr));
206 sunaddr.sun_family = AF_UNIX;
207 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
209 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0)
210 packet_disconnect("bind: %.100s", strerror(errno));
212 /* Restore the privileged uid. */
215 /* Start listening on the socket. */
216 if (listen(sock, SSH_LISTEN_BACKLOG) < 0)
217 packet_disconnect("listen: %.100s", strerror(errno));
219 /* Allocate a channel for the authentication agent socket. */
220 nc = channel_new("auth socket",
221 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
222 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
223 0, "auth socket", 1);
224 strlcpy(nc->path, auth_sock_name, sizeof(nc->path));
229 display_loginmsg(void)
231 if (buffer_len(&loginmsg) > 0) {
232 buffer_append(&loginmsg, "\0", 1);
233 printf("%s", (char *)buffer_ptr(&loginmsg));
234 buffer_clear(&loginmsg);
239 do_authenticated(Authctxt *authctxt)
241 setproctitle("%s", authctxt->pw->pw_name);
243 /* setup the channel layer */
244 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
245 channel_permit_all_opens();
248 do_authenticated2(authctxt);
250 do_authenticated1(authctxt);
252 do_cleanup(authctxt);
256 * Prepares for an interactive session. This is called after the user has
257 * been successfully authenticated. During this message exchange, pseudo
258 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
259 * are requested, etc.
262 do_authenticated1(Authctxt *authctxt)
266 int success, type, screen_flag;
267 int enable_compression_after_reply = 0;
268 u_int proto_len, data_len, dlen, compression_level = 0;
272 error("no more sessions");
275 s->authctxt = authctxt;
276 s->pw = authctxt->pw;
279 * We stay in this loop until the client requests to execute a shell
285 /* Get a packet from the client. */
286 type = packet_read();
288 /* Process the packet. */
290 case SSH_CMSG_REQUEST_COMPRESSION:
291 compression_level = packet_get_int();
293 if (compression_level < 1 || compression_level > 9) {
294 packet_send_debug("Received invalid compression level %d.",
298 if (options.compression == COMP_NONE) {
299 debug2("compression disabled");
302 /* Enable compression after we have responded with SUCCESS. */
303 enable_compression_after_reply = 1;
307 case SSH_CMSG_REQUEST_PTY:
308 success = session_pty_req(s);
311 case SSH_CMSG_X11_REQUEST_FORWARDING:
312 s->auth_proto = packet_get_string(&proto_len);
313 s->auth_data = packet_get_string(&data_len);
315 screen_flag = packet_get_protocol_flags() &
316 SSH_PROTOFLAG_SCREEN_NUMBER;
317 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
319 if (packet_remaining() == 4) {
321 debug2("Buggy client: "
322 "X11 screen flag missing");
323 s->screen = packet_get_int();
328 success = session_setup_x11fwd(s);
330 xfree(s->auth_proto);
332 s->auth_proto = NULL;
337 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
338 if (!options.allow_agent_forwarding ||
339 no_agent_forwarding_flag || compat13) {
340 debug("Authentication agent forwarding not permitted for this authentication.");
343 debug("Received authentication agent forwarding request.");
344 success = auth_input_request_forwarding(s->pw);
347 case SSH_CMSG_PORT_FORWARD_REQUEST:
348 if (no_port_forwarding_flag) {
349 debug("Port forwarding not permitted for this authentication.");
352 if (!options.allow_tcp_forwarding) {
353 debug("Port forwarding not permitted.");
356 debug("Received TCP/IP port forwarding request.");
357 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
358 options.gateway_ports) < 0) {
359 debug("Port forwarding failed.");
365 case SSH_CMSG_MAX_PACKET_SIZE:
366 if (packet_set_maxsize(packet_get_int()) > 0)
370 case SSH_CMSG_EXEC_SHELL:
371 case SSH_CMSG_EXEC_CMD:
372 if (type == SSH_CMSG_EXEC_CMD) {
373 command = packet_get_string(&dlen);
374 debug("Exec command '%.500s'", command);
386 * Any unknown messages in this phase are ignored,
387 * and a failure message is returned.
389 logit("Unknown packet type received after authentication: %d", type);
391 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
395 /* Enable compression now that we have replied if appropriate. */
396 if (enable_compression_after_reply) {
397 enable_compression_after_reply = 0;
398 packet_start_compression(compression_level);
404 * This is called to fork and execute a command when we have no tty. This
405 * will call do_child from the child, and server_loop from the parent after
406 * setting up file descriptors and such.
409 do_exec_no_pty(Session *s, const char *command)
414 int pin[2], pout[2], perr[2];
415 /* Allocate pipes for communicating with the program. */
416 if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
417 packet_disconnect("Could not create pipes: %.100s",
419 #else /* USE_PIPES */
420 int inout[2], err[2];
421 /* Uses socket pairs to communicate with the program. */
422 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
423 socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
424 packet_disconnect("Could not create socket pairs: %.100s",
426 #endif /* USE_PIPES */
428 fatal("do_exec_no_pty: no session");
430 session_proctitle(s);
432 /* Fork the child. */
433 if ((pid = fork()) == 0) {
436 /* Child. Reinitialize the log since the pid has changed. */
437 log_init(__progname, options.log_level, options.log_facility, log_stderr);
440 * Create a new session and process group since the 4.4BSD
441 * setlogin() affects the entire process group.
444 error("setsid failed: %.100s", strerror(errno));
448 * Redirect stdin. We close the parent side of the socket
449 * pair, and make the child side the standard input.
452 if (dup2(pin[0], 0) < 0)
453 perror("dup2 stdin");
456 /* Redirect stdout. */
458 if (dup2(pout[1], 1) < 0)
459 perror("dup2 stdout");
462 /* Redirect stderr. */
464 if (dup2(perr[1], 2) < 0)
465 perror("dup2 stderr");
467 #else /* USE_PIPES */
469 * Redirect stdin, stdout, and stderr. Stdin and stdout will
470 * use the same socket, as some programs (particularly rdist)
471 * seem to depend on it.
475 if (dup2(inout[0], 0) < 0) /* stdin */
476 perror("dup2 stdin");
477 if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
478 perror("dup2 stdout");
479 if (dup2(err[0], 2) < 0) /* stderr */
480 perror("dup2 stderr");
481 #endif /* USE_PIPES */
484 cray_init_job(s->pw); /* set up cray jid and tmpdir */
487 /* Do processing for the child (exec command etc). */
488 do_child(s, command);
492 signal(WJSIGNAL, cray_job_termination_handler);
496 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
499 packet_disconnect("fork failed: %.100s", strerror(errno));
501 /* Set interactive/non-interactive mode. */
502 packet_set_interactive(s->display != NULL);
504 /* We are the parent. Close the child sides of the pipes. */
510 if (s->is_subsystem) {
514 session_set_fds(s, pin[1], pout[0], perr[0]);
516 /* Enter the interactive session. */
517 server_loop(pid, pin[1], pout[0], perr[0]);
518 /* server_loop has closed pin[1], pout[0], and perr[0]. */
520 #else /* USE_PIPES */
521 /* We are the parent. Close the child sides of the socket pairs. */
526 * Clear loginmsg, since it's the child's responsibility to display
527 * it to the user, otherwise multiple sessions may accumulate
528 * multiple copies of the login messages.
530 buffer_clear(&loginmsg);
533 * Enter the interactive session. Note: server_loop must be able to
534 * handle the case that fdin and fdout are the same.
537 session_set_fds(s, inout[1], inout[1], s->is_subsystem ? -1 : err[1]);
539 server_loop(pid, inout[1], inout[1], err[1]);
540 /* server_loop has closed inout[1] and err[1]. */
542 #endif /* USE_PIPES */
546 * This is called to fork and execute a command when we have a tty. This
547 * will call do_child from the child, and server_loop from the parent after
548 * setting up file descriptors, controlling tty, updating wtmp, utmp,
549 * lastlog, and other such operations.
552 do_exec_pty(Session *s, const char *command)
554 int fdout, ptyfd, ttyfd, ptymaster;
558 fatal("do_exec_pty: no session");
562 /* Fork the child. */
563 if ((pid = fork()) == 0) {
566 /* Child. Reinitialize the log because the pid has changed. */
567 log_init(__progname, options.log_level, options.log_facility, log_stderr);
568 /* Close the master side of the pseudo tty. */
571 /* Make the pseudo tty our controlling tty. */
572 pty_make_controlling_tty(&ttyfd, s->tty);
574 /* Redirect stdin/stdout/stderr from the pseudo tty. */
575 if (dup2(ttyfd, 0) < 0)
576 error("dup2 stdin: %s", strerror(errno));
577 if (dup2(ttyfd, 1) < 0)
578 error("dup2 stdout: %s", strerror(errno));
579 if (dup2(ttyfd, 2) < 0)
580 error("dup2 stderr: %s", strerror(errno));
582 /* Close the extra descriptor for the pseudo tty. */
585 /* record login, etc. similar to login(1) */
587 if (!(options.use_login && command == NULL)) {
589 cray_init_job(s->pw); /* set up cray jid and tmpdir */
591 do_login(s, command);
593 # ifdef LOGIN_NEEDS_UTMPX
599 /* Do common processing for the child, such as execing the command. */
600 do_child(s, command);
604 signal(WJSIGNAL, cray_job_termination_handler);
608 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
611 packet_disconnect("fork failed: %.100s", strerror(errno));
614 /* Parent. Close the slave side of the pseudo tty. */
618 * Create another descriptor of the pty master side for use as the
619 * standard input. We could use the original descriptor, but this
620 * simplifies code in server_loop. The descriptor is bidirectional.
624 packet_disconnect("dup #1 failed: %.100s", strerror(errno));
626 /* we keep a reference to the pty master */
627 ptymaster = dup(ptyfd);
629 packet_disconnect("dup #2 failed: %.100s", strerror(errno));
630 s->ptymaster = ptymaster;
632 /* Enter interactive session. */
633 packet_set_interactive(1);
635 session_set_fds(s, ptyfd, fdout, -1);
637 server_loop(pid, ptyfd, fdout, -1);
638 /* server_loop _has_ closed ptyfd and fdout. */
642 #ifdef LOGIN_NEEDS_UTMPX
644 do_pre_login(Session *s)
647 struct sockaddr_storage from;
648 pid_t pid = getpid();
651 * Get IP address of client. If the connection is not a socket, let
652 * the address be 0.0.0.0.
654 memset(&from, 0, sizeof(from));
655 fromlen = sizeof(from);
656 if (packet_connection_is_on_socket()) {
657 if (getpeername(packet_get_connection_in(),
658 (struct sockaddr *)&from, &fromlen) < 0) {
659 debug("getpeername: %.100s", strerror(errno));
664 record_utmp_only(pid, s->tty, s->pw->pw_name,
665 get_remote_name_or_ip(utmp_len, options.use_dns),
666 (struct sockaddr *)&from, fromlen);
671 * This is called to fork and execute a command. If another command is
672 * to be forced, execute that instead.
675 do_exec(Session *s, const char *command)
677 if (options.adm_forced_command) {
678 original_command = command;
679 command = options.adm_forced_command;
680 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
681 s->is_subsystem = SUBSYSTEM_INT_SFTP;
682 else if (s->is_subsystem)
683 s->is_subsystem = SUBSYSTEM_EXT;
684 debug("Forced command (config) '%.900s'", command);
685 } else if (forced_command) {
686 original_command = command;
687 command = forced_command;
688 if (strcmp(INTERNAL_SFTP_NAME, command) == 0)
689 s->is_subsystem = SUBSYSTEM_INT_SFTP;
690 else if (s->is_subsystem)
691 s->is_subsystem = SUBSYSTEM_EXT;
692 debug("Forced command (key option) '%.900s'", command);
695 #ifdef SSH_AUDIT_EVENTS
697 PRIVSEP(audit_run_command(command));
698 else if (s->ttyfd == -1) {
699 char *shell = s->pw->pw_shell;
701 if (shell[0] == '\0') /* empty shell means /bin/sh */
703 PRIVSEP(audit_run_command(shell));
707 do_exec_pty(s, command);
709 do_exec_no_pty(s, command);
711 original_command = NULL;
714 * Clear loginmsg: it's the child's responsibility to display
715 * it to the user, otherwise multiple sessions may accumulate
716 * multiple copies of the login messages.
718 buffer_clear(&loginmsg);
721 /* administrative, login(1)-like work */
723 do_login(Session *s, const char *command)
726 struct sockaddr_storage from;
727 struct passwd * pw = s->pw;
728 pid_t pid = getpid();
731 * Get IP address of client. If the connection is not a socket, let
732 * the address be 0.0.0.0.
734 memset(&from, 0, sizeof(from));
735 fromlen = sizeof(from);
736 if (packet_connection_is_on_socket()) {
737 if (getpeername(packet_get_connection_in(),
738 (struct sockaddr *) & from, &fromlen) < 0) {
739 debug("getpeername: %.100s", strerror(errno));
744 /* Record that there was a login on that tty from the remote host. */
746 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
747 get_remote_name_or_ip(utmp_len,
749 (struct sockaddr *)&from, fromlen);
753 * If password change is needed, do it now.
754 * This needs to occur before the ~/.hushlogin check.
756 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
759 s->authctxt->force_pwchange = 0;
760 /* XXX - signal [net] parent to enable forwardings */
764 if (check_quietlogin(s, command))
773 * Display the message of the day.
781 if (options.print_motd) {
782 #ifdef HAVE_LOGIN_CAP
783 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
786 f = fopen("/etc/motd", "r");
789 while (fgets(buf, sizeof(buf), f))
798 * Check for quiet login, either .hushlogin or command given.
801 check_quietlogin(Session *s, const char *command)
804 struct passwd *pw = s->pw;
807 /* Return 1 if .hushlogin exists or a command given. */
810 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
811 #ifdef HAVE_LOGIN_CAP
812 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
815 if (stat(buf, &st) >= 0)
822 * Sets the value of the given variable in the environment. If the variable
823 * already exists, its value is overriden.
826 child_set_env(char ***envp, u_int *envsizep, const char *name,
834 * If we're passed an uninitialized list, allocate a single null
835 * entry before continuing.
837 if (*envp == NULL && *envsizep == 0) {
838 *envp = xmalloc(sizeof(char *));
844 * Find the slot where the value should be stored. If the variable
845 * already exists, we reuse the slot; otherwise we append a new slot
846 * at the end of the array, expanding if necessary.
849 namelen = strlen(name);
850 for (i = 0; env[i]; i++)
851 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
854 /* Reuse the slot. */
857 /* New variable. Expand if necessary. */
859 if (i >= envsize - 1) {
861 fatal("child_set_env: too many env vars");
863 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
866 /* Need to set the NULL pointer at end of array beyond the new slot. */
870 /* Allocate space and format the variable in the appropriate slot. */
871 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
872 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
876 * Reads environment variables from the given file and adds/overrides them
877 * into the environment. If the file does not exist, this does nothing.
878 * Otherwise, it must consist of empty lines, comments (line starts with '#')
879 * and assignments of the form name=value. No other forms are allowed.
882 read_environment_file(char ***env, u_int *envsize,
883 const char *filename)
890 f = fopen(filename, "r");
894 while (fgets(buf, sizeof(buf), f)) {
896 fatal("Too many lines in environment file %s", filename);
897 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
899 if (!*cp || *cp == '#' || *cp == '\n')
902 cp[strcspn(cp, "\n")] = '\0';
904 value = strchr(cp, '=');
906 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
911 * Replace the equals sign by nul, and advance value to
916 child_set_env(env, envsize, cp, value);
921 #ifdef HAVE_ETC_DEFAULT_LOGIN
923 * Return named variable from specified environment, or NULL if not present.
926 child_get_env(char **env, const char *name)
932 for (i=0; env[i] != NULL; i++)
933 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
934 return(env[i] + len + 1);
939 * Read /etc/default/login.
940 * We pick up the PATH (or SUPATH for root) and UMASK.
943 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
945 char **tmpenv = NULL, *var;
946 u_int i, tmpenvsize = 0;
950 * We don't want to copy the whole file to the child's environment,
951 * so we use a temporary environment and copy the variables we're
954 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
960 var = child_get_env(tmpenv, "SUPATH");
962 var = child_get_env(tmpenv, "PATH");
964 child_set_env(env, envsize, "PATH", var);
966 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
967 if (sscanf(var, "%5lo", &mask) == 1)
970 for (i = 0; tmpenv[i] != NULL; i++)
974 #endif /* HAVE_ETC_DEFAULT_LOGIN */
977 copy_environment(char **source, char ***env, u_int *envsize)
979 char *var_name, *var_val;
985 for(i = 0; source[i] != NULL; i++) {
986 var_name = xstrdup(source[i]);
987 if ((var_val = strstr(var_name, "=")) == NULL) {
993 debug3("Copy environment: %s=%s", var_name, var_val);
994 child_set_env(env, envsize, var_name, var_val);
1001 do_setup_env(Session *s, const char *shell)
1006 struct passwd *pw = s->pw;
1007 #ifndef HAVE_LOGIN_CAP
1011 /* Initialize the environment. */
1013 env = xcalloc(envsize, sizeof(char *));
1018 * The Windows environment contains some setting which are
1019 * important for a running system. They must not be dropped.
1024 p = fetch_windows_environment();
1025 copy_environment(p, &env, &envsize);
1026 free_windows_environment(p);
1031 /* Allow any GSSAPI methods that we've used to alter
1032 * the childs environment as they see fit
1034 ssh_gssapi_do_child(&env, &envsize);
1037 if (!options.use_login) {
1038 /* Set basic environment. */
1039 for (i = 0; i < s->num_env; i++)
1040 child_set_env(&env, &envsize, s->env[i].name,
1043 child_set_env(&env, &envsize, "USER", pw->pw_name);
1044 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1046 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1048 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1049 #ifdef HAVE_LOGIN_CAP
1050 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1051 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1053 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1054 #else /* HAVE_LOGIN_CAP */
1055 # ifndef HAVE_CYGWIN
1057 * There's no standard path on Windows. The path contains
1058 * important components pointing to the system directories,
1059 * needed for loading shared libraries. So the path better
1060 * remains intact here.
1062 # ifdef HAVE_ETC_DEFAULT_LOGIN
1063 read_etc_default_login(&env, &envsize, pw->pw_uid);
1064 path = child_get_env(env, "PATH");
1065 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1066 if (path == NULL || *path == '\0') {
1067 child_set_env(&env, &envsize, "PATH",
1068 s->pw->pw_uid == 0 ?
1069 SUPERUSER_PATH : _PATH_STDPATH);
1071 # endif /* HAVE_CYGWIN */
1072 #endif /* HAVE_LOGIN_CAP */
1074 snprintf(buf, sizeof buf, "%.200s/%.50s",
1075 _PATH_MAILDIR, pw->pw_name);
1076 child_set_env(&env, &envsize, "MAIL", buf);
1078 /* Normal systems set SHELL by default. */
1079 child_set_env(&env, &envsize, "SHELL", shell);
1082 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1084 /* Set custom environment options from RSA authentication. */
1085 if (!options.use_login) {
1086 while (custom_environment) {
1087 struct envstring *ce = custom_environment;
1090 for (i = 0; str[i] != '=' && str[i]; i++)
1092 if (str[i] == '=') {
1094 child_set_env(&env, &envsize, str, str + i + 1);
1096 custom_environment = ce->next;
1102 /* SSH_CLIENT deprecated */
1103 snprintf(buf, sizeof buf, "%.50s %d %d",
1104 get_remote_ipaddr(), get_remote_port(), get_local_port());
1105 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1107 laddr = get_local_ipaddr(packet_get_connection_in());
1108 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1109 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1111 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1114 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1116 child_set_env(&env, &envsize, "TERM", s->term);
1118 child_set_env(&env, &envsize, "DISPLAY", s->display);
1119 if (original_command)
1120 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1124 if (cray_tmpdir[0] != '\0')
1125 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1126 #endif /* _UNICOS */
1129 * Since we clear KRB5CCNAME at startup, if it's set now then it
1130 * must have been set by a native authentication method (eg AIX or
1131 * SIA), so copy it to the child.
1136 if ((cp = getenv("KRB5CCNAME")) != NULL)
1137 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1144 if ((cp = getenv("AUTHSTATE")) != NULL)
1145 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1146 read_environment_file(&env, &envsize, "/etc/environment");
1150 if (s->authctxt->krb5_ccname)
1151 child_set_env(&env, &envsize, "KRB5CCNAME",
1152 s->authctxt->krb5_ccname);
1156 * Pull in any environment variables that may have
1159 if (options.use_pam) {
1162 p = fetch_pam_child_environment();
1163 copy_environment(p, &env, &envsize);
1164 free_pam_environment(p);
1166 p = fetch_pam_environment();
1167 copy_environment(p, &env, &envsize);
1168 free_pam_environment(p);
1170 #endif /* USE_PAM */
1172 if (auth_sock_name != NULL)
1173 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1176 /* read $HOME/.ssh/environment. */
1177 if (options.permit_user_env && !options.use_login) {
1178 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1179 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1180 read_environment_file(&env, &envsize, buf);
1183 /* dump the environment */
1184 fprintf(stderr, "Environment:\n");
1185 for (i = 0; env[i]; i++)
1186 fprintf(stderr, " %.200s\n", env[i]);
1192 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1193 * first in this order).
1196 do_rc_files(Session *s, const char *shell)
1204 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1206 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1207 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1208 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1209 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1210 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1212 fprintf(stderr, "Running %s\n", cmd);
1213 f = popen(cmd, "w");
1216 fprintf(f, "%s %s\n", s->auth_proto,
1220 fprintf(stderr, "Could not run %s\n",
1222 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1224 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1225 _PATH_SSH_SYSTEM_RC);
1226 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1229 fprintf(f, "%s %s\n", s->auth_proto,
1233 fprintf(stderr, "Could not run %s\n",
1234 _PATH_SSH_SYSTEM_RC);
1235 } else if (do_xauth && options.xauth_location != NULL) {
1236 /* Add authority data to .Xauthority if appropriate. */
1239 "Running %.500s remove %.100s\n",
1240 options.xauth_location, s->auth_display);
1242 "%.500s add %.100s %.100s %.100s\n",
1243 options.xauth_location, s->auth_display,
1244 s->auth_proto, s->auth_data);
1246 snprintf(cmd, sizeof cmd, "%s -q -",
1247 options.xauth_location);
1248 f = popen(cmd, "w");
1250 fprintf(f, "remove %s\n",
1252 fprintf(f, "add %s %s %s\n",
1253 s->auth_display, s->auth_proto,
1257 fprintf(stderr, "Could not run %s\n",
1264 do_nologin(struct passwd *pw)
1269 #ifdef HAVE_LOGIN_CAP
1270 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1271 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1272 _PATH_NOLOGIN), "r");
1275 f = fopen(_PATH_NOLOGIN, "r");
1278 /* /etc/nologin exists. Print its contents and exit. */
1279 logit("User %.100s not allowed because %s exists",
1280 pw->pw_name, _PATH_NOLOGIN);
1281 while (fgets(buf, sizeof(buf), f))
1290 * Chroot into a directory after checking it for safety: all path components
1291 * must be root-owned directories with strict permissions.
1294 safely_chroot(const char *path, uid_t uid)
1297 char component[MAXPATHLEN];
1301 fatal("chroot path does not begin at root");
1302 if (strlen(path) >= sizeof(component))
1303 fatal("chroot path too long");
1306 * Descend the path, checking that each component is a
1307 * root-owned directory with strict permissions.
1309 for (cp = path; cp != NULL;) {
1310 if ((cp = strchr(cp, '/')) == NULL)
1311 strlcpy(component, path, sizeof(component));
1314 memcpy(component, path, cp - path);
1315 component[cp - path] = '\0';
1318 debug3("%s: checking '%s'", __func__, component);
1320 if (stat(component, &st) != 0)
1321 fatal("%s: stat(\"%s\"): %s", __func__,
1322 component, strerror(errno));
1323 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1324 fatal("bad ownership or modes for chroot "
1325 "directory %s\"%s\"",
1326 cp == NULL ? "" : "component ", component);
1327 if (!S_ISDIR(st.st_mode))
1328 fatal("chroot path %s\"%s\" is not a directory",
1329 cp == NULL ? "" : "component ", component);
1333 if (chdir(path) == -1)
1334 fatal("Unable to chdir to chroot path \"%s\": "
1335 "%s", path, strerror(errno));
1336 if (chroot(path) == -1)
1337 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1338 if (chdir("/") == -1)
1339 fatal("%s: chdir(/) after chroot: %s",
1340 __func__, strerror(errno));
1341 verbose("Changed root directory to \"%s\"", path);
1344 /* Set login name, uid, gid, and groups. */
1346 do_setusercontext(struct passwd *pw)
1348 char *chroot_path, *tmp;
1351 /* Cache selinux status for later use */
1352 (void)ssh_selinux_enabled();
1356 if (getuid() == 0 || geteuid() == 0)
1357 #endif /* HAVE_CYGWIN */
1360 #ifdef HAVE_SETPCRED
1361 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1362 fatal("Failed to set process credentials");
1363 #endif /* HAVE_SETPCRED */
1364 #ifdef HAVE_LOGIN_CAP
1369 if (options.use_pam) {
1370 do_pam_setcred(use_privsep);
1372 # endif /* USE_PAM */
1373 if (setusercontext(lc, pw, pw->pw_uid,
1374 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1375 perror("unable to set user context");
1379 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1380 /* Sets login uid for accounting */
1381 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1382 error("setluid: %s", strerror(errno));
1383 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1385 if (setlogin(pw->pw_name) < 0)
1386 error("setlogin failed: %s", strerror(errno));
1387 if (setgid(pw->pw_gid) < 0) {
1391 /* Initialize the group list. */
1392 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1393 perror("initgroups");
1399 * PAM credentials may take the form of supplementary groups.
1400 * These will have been wiped by the above initgroups() call.
1401 * Reestablish them here.
1403 if (options.use_pam) {
1404 do_pam_setcred(use_privsep);
1406 # endif /* USE_PAM */
1407 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1408 irix_setusercontext(pw);
1409 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1414 if (set_id(pw->pw_name) != 0) {
1417 # endif /* USE_LIBIAF */
1420 if (options.chroot_directory != NULL &&
1421 strcasecmp(options.chroot_directory, "none") != 0) {
1422 tmp = tilde_expand_filename(options.chroot_directory,
1424 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1425 "u", pw->pw_name, (char *)NULL);
1426 safely_chroot(chroot_path, pw->pw_uid);
1431 #ifdef HAVE_LOGIN_CAP
1432 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1433 perror("unable to set user context (setuser)");
1437 /* Permanently switch to the desired uid. */
1438 permanently_set_uid(pw);
1445 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1446 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1449 ssh_selinux_setup_exec_context(pw->pw_name);
1454 do_pwchange(Session *s)
1457 fprintf(stderr, "WARNING: Your password has expired.\n");
1458 if (s->ttyfd != -1) {
1460 "You must change your password now and login again!\n");
1461 #ifdef PASSWD_NEEDS_USERNAME
1462 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1465 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1470 "Password change required but no TTY available.\n");
1476 launch_login(struct passwd *pw, const char *hostname)
1478 /* Launch login(1). */
1480 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1481 #ifdef xxxLOGIN_NEEDS_TERM
1482 (s->term ? s->term : "unknown"),
1483 #endif /* LOGIN_NEEDS_TERM */
1484 #ifdef LOGIN_NO_ENDOPT
1485 "-p", "-f", pw->pw_name, (char *)NULL);
1487 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1490 /* Login couldn't be executed, die. */
1497 child_close_fds(void)
1501 if (packet_get_connection_in() == packet_get_connection_out())
1502 close(packet_get_connection_in());
1504 close(packet_get_connection_in());
1505 close(packet_get_connection_out());
1508 * Close all descriptors related to channels. They will still remain
1509 * open in the parent.
1511 /* XXX better use close-on-exec? -markus */
1512 channel_close_all();
1515 * Close any extra file descriptors. Note that there may still be
1516 * descriptors left by system functions. They will be closed later.
1521 * Close any extra open file descriptors so that we don't have them
1522 * hanging around in clients. Note that we want to do this after
1523 * initgroups, because at least on Solaris 2.3 it leaves file
1526 for (i = 3; i < 64; i++)
1531 * Performs common processing for the child, such as setting up the
1532 * environment, closing extra file descriptors, setting the user and group
1533 * ids, and executing the command or shell.
1537 do_child(Session *s, const char *command)
1539 extern char **environ;
1541 char *argv[ARGV_MAX];
1542 const char *shell, *shell0, *hostname = NULL;
1543 struct passwd *pw = s->pw;
1545 /* remove hostkey from the child's memory */
1546 destroy_sensitive_data();
1548 /* Force a password change */
1549 if (s->authctxt->force_pwchange) {
1550 do_setusercontext(pw);
1556 /* login(1) is only called if we execute the login shell */
1557 if (options.use_login && command != NULL)
1558 options.use_login = 0;
1561 cray_setup(pw->pw_uid, pw->pw_name, command);
1562 #endif /* _UNICOS */
1565 * Login(1) does this as well, and it needs uid 0 for the "-h"
1566 * switch, so we let login(1) to this for us.
1568 if (!options.use_login) {
1570 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1571 if (!check_quietlogin(s, command))
1573 #else /* HAVE_OSF_SIA */
1574 /* When PAM is enabled we rely on it to do the nologin check */
1575 if (!options.use_pam)
1577 do_setusercontext(pw);
1579 * PAM session modules in do_setusercontext may have
1580 * generated messages, so if this in an interactive
1581 * login then display them too.
1583 if (!check_quietlogin(s, command))
1585 #endif /* HAVE_OSF_SIA */
1589 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1590 debug3("PAM session not opened, exiting");
1597 * Get the shell from the password data. An empty shell field is
1598 * legal, and means /bin/sh.
1600 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1603 * Make sure $SHELL points to the shell from the password file,
1604 * even if shell is overridden from login.conf
1606 env = do_setup_env(s, shell);
1608 #ifdef HAVE_LOGIN_CAP
1609 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1612 /* we have to stash the hostname before we close our socket. */
1613 if (options.use_login)
1614 hostname = get_remote_name_or_ip(utmp_len,
1617 * Close the connection descriptors; note that this is the child, and
1618 * the server will still have the socket open, and it is important
1619 * that we do not shutdown it. Note that the descriptors cannot be
1620 * closed before building the environment, as we call
1621 * get_remote_ipaddr there.
1626 * Must take new environment into use so that .ssh/rc,
1627 * /etc/ssh/sshrc and xauth are run in the proper environment.
1631 #if defined(KRB5) && defined(USE_AFS)
1633 * At this point, we check to see if AFS is active and if we have
1634 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1635 * if we can (and need to) extend the ticket into an AFS token. If
1636 * we don't do this, we run into potential problems if the user's
1637 * home directory is in AFS and it's not world-readable.
1640 if (options.kerberos_get_afs_token && k_hasafs() &&
1641 (s->authctxt->krb5_ctx != NULL)) {
1644 debug("Getting AFS token");
1648 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1649 krb5_afslog(s->authctxt->krb5_ctx,
1650 s->authctxt->krb5_fwd_ccache, cell, NULL);
1652 krb5_afslog_home(s->authctxt->krb5_ctx,
1653 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1657 /* Change current directory to the user's home directory. */
1658 if (chdir(pw->pw_dir) < 0) {
1659 fprintf(stderr, "Could not chdir to home directory %s: %s\n",
1660 pw->pw_dir, strerror(errno));
1661 #ifdef HAVE_LOGIN_CAP
1662 if (login_getcapbool(lc, "requirehome", 0))
1667 closefrom(STDERR_FILENO + 1);
1669 if (!options.use_login)
1670 do_rc_files(s, shell);
1672 /* restore SIGPIPE for child */
1673 signal(SIGPIPE, SIG_DFL);
1675 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1676 extern int optind, optreset;
1680 setproctitle("%s@internal-sftp-server", s->pw->pw_name);
1681 args = strdup(command ? command : "sftp-server");
1682 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1683 if (i < ARGV_MAX - 1)
1686 optind = optreset = 1;
1687 __progname = argv[0];
1688 exit(sftp_server_main(i, argv, s->pw));
1691 if (options.use_login) {
1692 launch_login(pw, hostname);
1696 /* Get the last component of the shell name. */
1697 if ((shell0 = strrchr(shell, '/')) != NULL)
1703 * If we have no command, execute the shell. In this case, the shell
1704 * name to be passed in argv[0] is preceded by '-' to indicate that
1705 * this is a login shell.
1710 /* Start the shell. Set initial character to '-'. */
1713 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1714 >= sizeof(argv0) - 1) {
1720 /* Execute the shell. */
1723 execve(shell, argv, env);
1725 /* Executing the shell failed. */
1730 * Execute the command using the user's shell. This uses the -c
1731 * option to execute the command.
1733 argv[0] = (char *) shell0;
1735 argv[2] = (char *) command;
1737 execve(shell, argv, env);
1746 static int did_init = 0;
1748 debug("session_new: init");
1749 for (i = 0; i < MAX_SESSIONS; i++) {
1750 sessions[i].used = 0;
1754 for (i = 0; i < MAX_SESSIONS; i++) {
1755 Session *s = &sessions[i];
1757 memset(s, 0, sizeof(*s));
1763 s->x11_chanids = NULL;
1764 debug("session_new: session %d", i);
1775 for (i = 0; i < MAX_SESSIONS; i++) {
1776 Session *s = &sessions[i];
1777 debug("dump: used %d session %d %p channel %d pid %ld",
1787 session_open(Authctxt *authctxt, int chanid)
1789 Session *s = session_new();
1790 debug("session_open: channel %d", chanid);
1792 error("no more sessions");
1795 s->authctxt = authctxt;
1796 s->pw = authctxt->pw;
1797 if (s->pw == NULL || !authctxt->valid)
1798 fatal("no user for session %d", s->self);
1799 debug("session_open: session %d: link with channel %d", s->self, chanid);
1805 session_by_tty(char *tty)
1808 for (i = 0; i < MAX_SESSIONS; i++) {
1809 Session *s = &sessions[i];
1810 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1811 debug("session_by_tty: session %d tty %s", i, tty);
1815 debug("session_by_tty: unknown tty %.100s", tty);
1821 session_by_channel(int id)
1824 for (i = 0; i < MAX_SESSIONS; i++) {
1825 Session *s = &sessions[i];
1826 if (s->used && s->chanid == id) {
1827 debug("session_by_channel: session %d channel %d", i, id);
1831 debug("session_by_channel: unknown channel %d", id);
1837 session_by_x11_channel(int id)
1841 for (i = 0; i < MAX_SESSIONS; i++) {
1842 Session *s = &sessions[i];
1844 if (s->x11_chanids == NULL || !s->used)
1846 for (j = 0; s->x11_chanids[j] != -1; j++) {
1847 if (s->x11_chanids[j] == id) {
1848 debug("session_by_x11_channel: session %d "
1849 "channel %d", s->self, id);
1854 debug("session_by_x11_channel: unknown channel %d", id);
1860 session_by_pid(pid_t pid)
1863 debug("session_by_pid: pid %ld", (long)pid);
1864 for (i = 0; i < MAX_SESSIONS; i++) {
1865 Session *s = &sessions[i];
1866 if (s->used && s->pid == pid)
1869 error("session_by_pid: unknown pid %ld", (long)pid);
1875 session_window_change_req(Session *s)
1877 s->col = packet_get_int();
1878 s->row = packet_get_int();
1879 s->xpixel = packet_get_int();
1880 s->ypixel = packet_get_int();
1882 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1887 session_pty_req(Session *s)
1893 debug("Allocating a pty not permitted for this authentication.");
1896 if (s->ttyfd != -1) {
1897 packet_disconnect("Protocol error: you already have a pty.");
1901 s->term = packet_get_string(&len);
1904 s->col = packet_get_int();
1905 s->row = packet_get_int();
1907 s->row = packet_get_int();
1908 s->col = packet_get_int();
1910 s->xpixel = packet_get_int();
1911 s->ypixel = packet_get_int();
1913 if (strcmp(s->term, "") == 0) {
1918 /* Allocate a pty and open it. */
1919 debug("Allocating pty.");
1920 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)))) {
1926 error("session_pty_req: session %d alloc failed", s->self);
1929 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1931 /* for SSH1 the tty modes length is not given */
1933 n_bytes = packet_remaining();
1934 tty_parse_modes(s->ttyfd, &n_bytes);
1937 pty_setowner(s->pw, s->tty);
1939 /* Set window size from the packet. */
1940 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1943 session_proctitle(s);
1948 session_subsystem_req(Session *s)
1953 char *prog, *cmd, *subsys = packet_get_string(&len);
1957 logit("subsystem request for %.100s", subsys);
1959 for (i = 0; i < options.num_subsystems; i++) {
1960 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
1961 prog = options.subsystem_command[i];
1962 cmd = options.subsystem_args[i];
1963 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
1964 s->is_subsystem = SUBSYSTEM_INT_SFTP;
1965 } else if (stat(prog, &st) < 0) {
1966 error("subsystem: cannot stat %s: %s", prog,
1970 s->is_subsystem = SUBSYSTEM_EXT;
1972 debug("subsystem: exec() %s", cmd);
1980 logit("subsystem request for %.100s failed, subsystem not found",
1988 session_x11_req(Session *s)
1992 if (s->auth_proto != NULL || s->auth_data != NULL) {
1993 error("session_x11_req: session %d: "
1994 "x11 forwarding already active", s->self);
1997 s->single_connection = packet_get_char();
1998 s->auth_proto = packet_get_string(NULL);
1999 s->auth_data = packet_get_string(NULL);
2000 s->screen = packet_get_int();
2003 success = session_setup_x11fwd(s);
2005 xfree(s->auth_proto);
2006 xfree(s->auth_data);
2007 s->auth_proto = NULL;
2008 s->auth_data = NULL;
2014 session_shell_req(Session *s)
2022 session_exec_req(Session *s)
2025 char *command = packet_get_string(&len);
2027 do_exec(s, command);
2033 session_break_req(Session *s)
2036 packet_get_int(); /* ignored */
2039 if (s->ttyfd == -1 ||
2040 tcsendbreak(s->ttyfd, 0) < 0)
2046 session_env_req(Session *s)
2049 u_int name_len, val_len, i;
2051 name = packet_get_string(&name_len);
2052 val = packet_get_string(&val_len);
2055 /* Don't set too many environment variables */
2056 if (s->num_env > 128) {
2057 debug2("Ignoring env request %s: too many env vars", name);
2061 for (i = 0; i < options.num_accept_env; i++) {
2062 if (match_pattern(name, options.accept_env[i])) {
2063 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2064 s->env = xrealloc(s->env, s->num_env + 1,
2066 s->env[s->num_env].name = name;
2067 s->env[s->num_env].val = val;
2072 debug2("Ignoring env request %s: disallowed name", name);
2081 session_auth_agent_req(Session *s)
2083 static int called = 0;
2085 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2086 debug("session_auth_agent_req: no_agent_forwarding_flag");
2093 return auth_input_request_forwarding(s->pw);
2098 session_input_channel_req(Channel *c, const char *rtype)
2103 if ((s = session_by_channel(c->self)) == NULL) {
2104 logit("session_input_channel_req: no session %d req %.100s",
2108 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2111 * a session is in LARVAL state until a shell, a command
2112 * or a subsystem is executed
2114 if (c->type == SSH_CHANNEL_LARVAL) {
2115 if (strcmp(rtype, "shell") == 0) {
2116 success = session_shell_req(s);
2117 } else if (strcmp(rtype, "exec") == 0) {
2118 success = session_exec_req(s);
2119 } else if (strcmp(rtype, "pty-req") == 0) {
2120 success = session_pty_req(s);
2121 } else if (strcmp(rtype, "x11-req") == 0) {
2122 success = session_x11_req(s);
2123 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2124 success = session_auth_agent_req(s);
2125 } else if (strcmp(rtype, "subsystem") == 0) {
2126 success = session_subsystem_req(s);
2127 } else if (strcmp(rtype, "env") == 0) {
2128 success = session_env_req(s);
2131 if (strcmp(rtype, "window-change") == 0) {
2132 success = session_window_change_req(s);
2133 } else if (strcmp(rtype, "break") == 0) {
2134 success = session_break_req(s);
2141 session_set_fds(Session *s, int fdin, int fdout, int fderr)
2144 fatal("session_set_fds: called for proto != 2.0");
2146 * now that have a child and a pipe to the child,
2147 * we can activate our channel and register the fd's
2149 if (s->chanid == -1)
2150 fatal("no channel for session %d", s->self);
2151 channel_set_fds(s->chanid,
2153 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2155 CHAN_SES_WINDOW_DEFAULT);
2159 * Function to perform pty cleanup. Also called if we get aborted abnormally
2160 * (e.g., due to a dropped connection).
2163 session_pty_cleanup2(Session *s)
2166 error("session_pty_cleanup: no session");
2172 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2174 /* Record that the user has logged out. */
2176 record_logout(s->pid, s->tty, s->pw->pw_name);
2178 /* Release the pseudo-tty. */
2180 pty_release(s->tty);
2183 * Close the server side of the socket pairs. We must do this after
2184 * the pty cleanup, so that another process doesn't get this pty
2185 * while we're still cleaning up.
2187 if (close(s->ptymaster) < 0)
2188 error("close(s->ptymaster/%d): %s", s->ptymaster, strerror(errno));
2190 /* unlink pty from session */
2195 session_pty_cleanup(Session *s)
2197 PRIVSEP(session_pty_cleanup2(s));
2203 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2218 return "SIG@openssh.com";
2222 session_close_x11(int id)
2226 if ((c = channel_by_id(id)) == NULL) {
2227 debug("session_close_x11: x11 channel %d missing", id);
2229 /* Detach X11 listener */
2230 debug("session_close_x11: detach x11 channel %d", id);
2231 channel_cancel_cleanup(id);
2232 if (c->ostate != CHAN_OUTPUT_CLOSED)
2238 session_close_single_x11(int id, void *arg)
2243 debug3("session_close_single_x11: channel %d", id);
2244 channel_cancel_cleanup(id);
2245 if ((s = session_by_x11_channel(id)) == NULL)
2246 fatal("session_close_single_x11: no x11 channel %d", id);
2247 for (i = 0; s->x11_chanids[i] != -1; i++) {
2248 debug("session_close_single_x11: session %d: "
2249 "closing channel %d", s->self, s->x11_chanids[i]);
2251 * The channel "id" is already closing, but make sure we
2252 * close all of its siblings.
2254 if (s->x11_chanids[i] != id)
2255 session_close_x11(s->x11_chanids[i]);
2257 xfree(s->x11_chanids);
2258 s->x11_chanids = NULL;
2263 if (s->auth_proto) {
2264 xfree(s->auth_proto);
2265 s->auth_proto = NULL;
2268 xfree(s->auth_data);
2269 s->auth_data = NULL;
2271 if (s->auth_display) {
2272 xfree(s->auth_display);
2273 s->auth_display = NULL;
2278 session_exit_message(Session *s, int status)
2282 if ((c = channel_lookup(s->chanid)) == NULL)
2283 fatal("session_exit_message: session %d: no channel %d",
2284 s->self, s->chanid);
2285 debug("session_exit_message: session %d channel %d pid %ld",
2286 s->self, s->chanid, (long)s->pid);
2288 if (WIFEXITED(status)) {
2289 channel_request_start(s->chanid, "exit-status", 0);
2290 packet_put_int(WEXITSTATUS(status));
2292 } else if (WIFSIGNALED(status)) {
2293 channel_request_start(s->chanid, "exit-signal", 0);
2294 packet_put_cstring(sig2name(WTERMSIG(status)));
2296 packet_put_char(WCOREDUMP(status)? 1 : 0);
2297 #else /* WCOREDUMP */
2299 #endif /* WCOREDUMP */
2300 packet_put_cstring("");
2301 packet_put_cstring("");
2304 /* Some weird exit cause. Just exit. */
2305 packet_disconnect("wait returned status %04x.", status);
2308 /* disconnect channel */
2309 debug("session_exit_message: release channel %d", s->chanid);
2312 * Adjust cleanup callback attachment to send close messages when
2313 * the channel gets EOF. The session will be then be closed
2314 * by session_close_by_channel when the childs close their fds.
2316 channel_register_cleanup(c->self, session_close_by_channel, 1);
2319 * emulate a write failure with 'chan_write_failed', nobody will be
2320 * interested in data we write.
2321 * Note that we must not call 'chan_read_failed', since there could
2322 * be some more data waiting in the pipe.
2324 if (c->ostate != CHAN_OUTPUT_CLOSED)
2325 chan_write_failed(c);
2329 session_close(Session *s)
2333 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2335 session_pty_cleanup(s);
2341 xfree(s->x11_chanids);
2342 if (s->auth_display)
2343 xfree(s->auth_display);
2345 xfree(s->auth_data);
2347 xfree(s->auth_proto);
2349 if (s->env != NULL) {
2350 for (i = 0; i < s->num_env; i++) {
2351 xfree(s->env[i].name);
2352 xfree(s->env[i].val);
2356 session_proctitle(s);
2360 session_close_by_pid(pid_t pid, int status)
2362 Session *s = session_by_pid(pid);
2364 debug("session_close_by_pid: no session for pid %ld",
2368 if (s->chanid != -1)
2369 session_exit_message(s, status);
2371 session_pty_cleanup(s);
2376 * this is called when a channel dies before
2377 * the session 'child' itself dies
2380 session_close_by_channel(int id, void *arg)
2382 Session *s = session_by_channel(id);
2386 debug("session_close_by_channel: no session for id %d", id);
2389 debug("session_close_by_channel: channel %d child %ld",
2392 debug("session_close_by_channel: channel %d: has child", id);
2394 * delay detach of session, but release pty, since
2395 * the fd's to the child are already closed
2398 session_pty_cleanup(s);
2401 /* detach by removing callback */
2402 channel_cancel_cleanup(s->chanid);
2404 /* Close any X11 listeners associated with this session */
2405 if (s->x11_chanids != NULL) {
2406 for (i = 0; s->x11_chanids[i] != -1; i++) {
2407 session_close_x11(s->x11_chanids[i]);
2408 s->x11_chanids[i] = -1;
2417 session_destroy_all(void (*closefunc)(Session *))
2420 for (i = 0; i < MAX_SESSIONS; i++) {
2421 Session *s = &sessions[i];
2423 if (closefunc != NULL)
2432 session_tty_list(void)
2434 static char buf[1024];
2439 for (i = 0; i < MAX_SESSIONS; i++) {
2440 Session *s = &sessions[i];
2441 if (s->used && s->ttyfd != -1) {
2443 if (strncmp(s->tty, "/dev/", 5) != 0) {
2444 cp = strrchr(s->tty, '/');
2445 cp = (cp == NULL) ? s->tty : cp + 1;
2450 strlcat(buf, ",", sizeof buf);
2451 strlcat(buf, cp, sizeof buf);
2455 strlcpy(buf, "notty", sizeof buf);
2460 session_proctitle(Session *s)
2463 error("no user for session %d", s->self);
2465 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2469 session_setup_x11fwd(Session *s)
2472 char display[512], auth_display[512];
2473 char hostname[MAXHOSTNAMELEN];
2476 if (no_x11_forwarding_flag) {
2477 packet_send_debug("X11 forwarding disabled in user configuration file.");
2480 if (!options.x11_forwarding) {
2481 debug("X11 forwarding disabled in server configuration file.");
2484 if (!options.xauth_location ||
2485 (stat(options.xauth_location, &st) == -1)) {
2486 packet_send_debug("No xauth program; cannot forward with spoofing.");
2489 if (options.use_login) {
2490 packet_send_debug("X11 forwarding disabled; "
2491 "not compatible with UseLogin=yes.");
2494 if (s->display != NULL) {
2495 debug("X11 display already set.");
2498 if (x11_create_display_inet(options.x11_display_offset,
2499 options.x11_use_localhost, s->single_connection,
2500 &s->display_number, &s->x11_chanids) == -1) {
2501 debug("x11_create_display_inet failed.");
2504 for (i = 0; s->x11_chanids[i] != -1; i++) {
2505 channel_register_cleanup(s->x11_chanids[i],
2506 session_close_single_x11, 0);
2509 /* Set up a suitable value for the DISPLAY variable. */
2510 if (gethostname(hostname, sizeof(hostname)) < 0)
2511 fatal("gethostname: %.100s", strerror(errno));
2513 * auth_display must be used as the displayname when the
2514 * authorization entry is added with xauth(1). This will be
2515 * different than the DISPLAY string for localhost displays.
2517 if (options.x11_use_localhost) {
2518 snprintf(display, sizeof display, "localhost:%u.%u",
2519 s->display_number, s->screen);
2520 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2521 s->display_number, s->screen);
2522 s->display = xstrdup(display);
2523 s->auth_display = xstrdup(auth_display);
2525 #ifdef IPADDR_IN_DISPLAY
2527 struct in_addr my_addr;
2529 he = gethostbyname(hostname);
2531 error("Can't get IP address for X11 DISPLAY.");
2532 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2535 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2536 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2537 s->display_number, s->screen);
2539 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2540 s->display_number, s->screen);
2542 s->display = xstrdup(display);
2543 s->auth_display = xstrdup(display);
2550 do_authenticated2(Authctxt *authctxt)
2552 server_loop2(authctxt);
2556 do_cleanup(Authctxt *authctxt)
2558 static int called = 0;
2560 debug("do_cleanup");
2562 /* no cleanup if we're in the child for login shell */
2566 /* avoid double cleanup */
2571 if (authctxt == NULL)
2575 if (options.use_pam) {
2577 sshpam_thread_cleanup();
2581 if (!authctxt->authenticated)
2585 if (options.kerberos_ticket_cleanup &&
2587 krb5_cleanup_proc(authctxt);
2591 if (compat20 && options.gss_cleanup_creds)
2592 ssh_gssapi_cleanup_creds();
2595 /* remove agent socket */
2596 auth_sock_cleanup_proc(authctxt->pw);
2599 * Cleanup ptys/utmp only if privsep is disabled,
2600 * or if running in monitor.
2602 if (!use_privsep || mm_is_monitor())
2603 session_destroy_all(session_pty_cleanup2);