1 /* $OpenBSD: session.c,v 1.246 2009/04/17 19:23:06 stevesk 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)
98 #define IS_INTERNAL_SFTP(c) \
99 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
100 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
101 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
102 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
106 Session *session_new(void);
107 void session_set_fds(Session *, int, int, int, int);
108 void session_pty_cleanup(Session *);
109 void session_proctitle(Session *);
110 int session_setup_x11fwd(Session *);
111 int do_exec_pty(Session *, const char *);
112 int do_exec_no_pty(Session *, const char *);
113 int do_exec(Session *, const char *);
114 void do_login(Session *, const char *);
115 #ifdef LOGIN_NEEDS_UTMPX
116 static void do_pre_login(Session *s);
118 void do_child(Session *, const char *);
120 int check_quietlogin(Session *, const char *);
122 static void do_authenticated1(Authctxt *);
123 static void do_authenticated2(Authctxt *);
125 static int session_pty_req(Session *);
128 extern ServerOptions options;
129 extern char *__progname;
130 extern int log_stderr;
131 extern int debug_flag;
132 extern u_int utmp_len;
133 extern int startup_pipe;
134 extern void destroy_sensitive_data(void);
135 extern Buffer loginmsg;
137 /* original command from peer. */
138 const char *original_command = NULL;
141 static int sessions_first_unused = -1;
142 static int sessions_nalloc = 0;
143 static Session *sessions = NULL;
145 #define SUBSYSTEM_NONE 0
146 #define SUBSYSTEM_EXT 1
147 #define SUBSYSTEM_INT_SFTP 2
149 #ifdef HAVE_LOGIN_CAP
153 static int is_child = 0;
155 /* Name and directory of socket for authentication agent forwarding. */
156 static char *auth_sock_name = NULL;
157 static char *auth_sock_dir = NULL;
159 /* removes the agent forwarding socket */
162 auth_sock_cleanup_proc(struct passwd *pw)
164 if (auth_sock_name != NULL) {
165 temporarily_use_uid(pw);
166 unlink(auth_sock_name);
167 rmdir(auth_sock_dir);
168 auth_sock_name = NULL;
174 auth_input_request_forwarding(struct passwd * pw)
178 struct sockaddr_un sunaddr;
180 if (auth_sock_name != NULL) {
181 error("authentication forwarding requested twice.");
185 /* Temporarily drop privileged uid for mkdir/bind. */
186 temporarily_use_uid(pw);
188 /* Allocate a buffer for the socket name, and format the name. */
189 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
191 /* Create private directory for socket */
192 if (mkdtemp(auth_sock_dir) == NULL) {
193 packet_send_debug("Agent forwarding disabled: "
194 "mkdtemp() failed: %.100s", strerror(errno));
196 xfree(auth_sock_dir);
197 auth_sock_dir = NULL;
201 xasprintf(&auth_sock_name, "%s/agent.%ld",
202 auth_sock_dir, (long) getpid());
204 /* Create the socket. */
205 sock = socket(AF_UNIX, SOCK_STREAM, 0);
207 error("socket: %.100s", strerror(errno));
212 /* Bind it to the name. */
213 memset(&sunaddr, 0, sizeof(sunaddr));
214 sunaddr.sun_family = AF_UNIX;
215 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
217 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
218 error("bind: %.100s", strerror(errno));
223 /* Restore the privileged uid. */
226 /* Start listening on the socket. */
227 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
228 error("listen: %.100s", strerror(errno));
232 /* Allocate a channel for the authentication agent socket. */
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 nc->path = xstrdup(auth_sock_name);
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);
278 do_cleanup(authctxt);
282 * Prepares for an interactive session. This is called after the user has
283 * been successfully authenticated. During this message exchange, pseudo
284 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
285 * are requested, etc.
288 do_authenticated1(Authctxt *authctxt)
292 int success, type, screen_flag;
293 int enable_compression_after_reply = 0;
294 u_int proto_len, data_len, dlen, compression_level = 0;
298 error("no more sessions");
301 s->authctxt = authctxt;
302 s->pw = authctxt->pw;
305 * We stay in this loop until the client requests to execute a shell
311 /* Get a packet from the client. */
312 type = packet_read();
314 /* Process the packet. */
316 case SSH_CMSG_REQUEST_COMPRESSION:
317 compression_level = packet_get_int();
319 if (compression_level < 1 || compression_level > 9) {
320 packet_send_debug("Received invalid compression level %d.",
324 if (options.compression == COMP_NONE) {
325 debug2("compression disabled");
328 /* Enable compression after we have responded with SUCCESS. */
329 enable_compression_after_reply = 1;
333 case SSH_CMSG_REQUEST_PTY:
334 success = session_pty_req(s);
337 case SSH_CMSG_X11_REQUEST_FORWARDING:
338 s->auth_proto = packet_get_string(&proto_len);
339 s->auth_data = packet_get_string(&data_len);
341 screen_flag = packet_get_protocol_flags() &
342 SSH_PROTOFLAG_SCREEN_NUMBER;
343 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
345 if (packet_remaining() == 4) {
347 debug2("Buggy client: "
348 "X11 screen flag missing");
349 s->screen = packet_get_int();
354 success = session_setup_x11fwd(s);
356 xfree(s->auth_proto);
358 s->auth_proto = NULL;
363 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
364 if (!options.allow_agent_forwarding ||
365 no_agent_forwarding_flag || compat13) {
366 debug("Authentication agent forwarding not permitted for this authentication.");
369 debug("Received authentication agent forwarding request.");
370 success = auth_input_request_forwarding(s->pw);
373 case SSH_CMSG_PORT_FORWARD_REQUEST:
374 if (no_port_forwarding_flag) {
375 debug("Port forwarding not permitted for this authentication.");
378 if (!options.allow_tcp_forwarding) {
379 debug("Port forwarding not permitted.");
382 debug("Received TCP/IP port forwarding request.");
383 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
384 options.gateway_ports) < 0) {
385 debug("Port forwarding failed.");
391 case SSH_CMSG_MAX_PACKET_SIZE:
392 if (packet_set_maxsize(packet_get_int()) > 0)
396 case SSH_CMSG_EXEC_SHELL:
397 case SSH_CMSG_EXEC_CMD:
398 if (type == SSH_CMSG_EXEC_CMD) {
399 command = packet_get_string(&dlen);
400 debug("Exec command '%.500s'", command);
401 if (do_exec(s, command) != 0)
403 "command execution failed");
406 if (do_exec(s, NULL) != 0)
408 "shell execution failed");
416 * Any unknown messages in this phase are ignored,
417 * and a failure message is returned.
419 logit("Unknown packet type received after authentication: %d", type);
421 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
425 /* Enable compression now that we have replied if appropriate. */
426 if (enable_compression_after_reply) {
427 enable_compression_after_reply = 0;
428 packet_start_compression(compression_level);
435 * This is called to fork and execute a command when we have no tty. This
436 * will call do_child from the child, and server_loop from the parent after
437 * setting up file descriptors and such.
440 do_exec_no_pty(Session *s, const char *command)
445 int pin[2], pout[2], perr[2];
447 /* Allocate pipes for communicating with the program. */
449 error("%s: pipe in: %.100s", __func__, strerror(errno));
452 if (pipe(pout) < 0) {
453 error("%s: pipe out: %.100s", __func__, strerror(errno));
458 if (pipe(perr) < 0) {
459 error("%s: pipe err: %.100s", __func__, strerror(errno));
467 int inout[2], err[2];
469 /* Uses socket pairs to communicate with the program. */
470 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
471 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
474 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
475 error("%s: socketpair #2: %.100s", __func__, strerror(errno));
483 fatal("do_exec_no_pty: no session");
485 session_proctitle(s);
487 /* Fork the child. */
488 switch ((pid = fork())) {
490 error("%s: fork: %.100s", __func__, strerror(errno));
508 /* Child. Reinitialize the log since the pid has changed. */
509 log_init(__progname, options.log_level,
510 options.log_facility, log_stderr);
513 * Create a new session and process group since the 4.4BSD
514 * setlogin() affects the entire process group.
517 error("setsid failed: %.100s", strerror(errno));
521 * Redirect stdin. We close the parent side of the socket
522 * pair, and make the child side the standard input.
525 if (dup2(pin[0], 0) < 0)
526 perror("dup2 stdin");
529 /* Redirect stdout. */
531 if (dup2(pout[1], 1) < 0)
532 perror("dup2 stdout");
535 /* Redirect stderr. */
537 if (dup2(perr[1], 2) < 0)
538 perror("dup2 stderr");
542 * Redirect stdin, stdout, and stderr. Stdin and stdout will
543 * use the same socket, as some programs (particularly rdist)
544 * seem to depend on it.
548 if (dup2(inout[0], 0) < 0) /* stdin */
549 perror("dup2 stdin");
550 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
551 perror("dup2 stdout");
553 if (dup2(err[0], 2) < 0) /* stderr */
554 perror("dup2 stderr");
560 cray_init_job(s->pw); /* set up cray jid and tmpdir */
563 /* Do processing for the child (exec command etc). */
564 do_child(s, command);
571 signal(WJSIGNAL, cray_job_termination_handler);
574 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
578 /* Set interactive/non-interactive mode. */
579 packet_set_interactive(s->display != NULL);
582 * Clear loginmsg, since it's the child's responsibility to display
583 * it to the user, otherwise multiple sessions may accumulate
584 * multiple copies of the login messages.
586 buffer_clear(&loginmsg);
589 /* We are the parent. Close the child sides of the pipes. */
595 if (s->is_subsystem) {
599 session_set_fds(s, pin[1], pout[0], perr[0], 0);
601 /* Enter the interactive session. */
602 server_loop(pid, pin[1], pout[0], perr[0]);
603 /* server_loop has closed pin[1], pout[0], and perr[0]. */
606 /* We are the parent. Close the child sides of the socket pairs. */
611 * Enter the interactive session. Note: server_loop must be able to
612 * handle the case that fdin and fdout are the same.
615 session_set_fds(s, inout[1], inout[1],
616 s->is_subsystem ? -1 : err[1], 0);
620 server_loop(pid, inout[1], inout[1], err[1]);
621 /* server_loop has closed inout[1] and err[1]. */
628 * This is called to fork and execute a command when we have a tty. This
629 * will call do_child from the child, and server_loop from the parent after
630 * setting up file descriptors, controlling tty, updating wtmp, utmp,
631 * lastlog, and other such operations.
634 do_exec_pty(Session *s, const char *command)
636 int fdout, ptyfd, ttyfd, ptymaster;
640 fatal("do_exec_pty: no session");
645 * Create another descriptor of the pty master side for use as the
646 * standard input. We could use the original descriptor, but this
647 * simplifies code in server_loop. The descriptor is bidirectional.
648 * Do this before forking (and cleanup in the child) so as to
649 * detect and gracefully fail out-of-fd conditions.
651 if ((fdout = dup(ptyfd)) < 0) {
652 error("%s: dup #1: %s", __func__, strerror(errno));
657 /* we keep a reference to the pty master */
658 if ((ptymaster = dup(ptyfd)) < 0) {
659 error("%s: dup #2: %s", __func__, strerror(errno));
666 /* Fork the child. */
667 switch ((pid = fork())) {
669 error("%s: fork: %.100s", __func__, strerror(errno));
681 /* Child. Reinitialize the log because the pid has changed. */
682 log_init(__progname, options.log_level,
683 options.log_facility, log_stderr);
684 /* Close the master side of the pseudo tty. */
687 /* Make the pseudo tty our controlling tty. */
688 pty_make_controlling_tty(&ttyfd, s->tty);
690 /* Redirect stdin/stdout/stderr from the pseudo tty. */
691 if (dup2(ttyfd, 0) < 0)
692 error("dup2 stdin: %s", strerror(errno));
693 if (dup2(ttyfd, 1) < 0)
694 error("dup2 stdout: %s", strerror(errno));
695 if (dup2(ttyfd, 2) < 0)
696 error("dup2 stderr: %s", strerror(errno));
698 /* Close the extra descriptor for the pseudo tty. */
701 /* record login, etc. similar to login(1) */
703 if (!(options.use_login && command == NULL)) {
705 cray_init_job(s->pw); /* set up cray jid and tmpdir */
707 do_login(s, command);
709 # ifdef LOGIN_NEEDS_UTMPX
715 * Do common processing for the child, such as execing
718 do_child(s, command);
725 signal(WJSIGNAL, cray_job_termination_handler);
728 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
733 /* Parent. Close the slave side of the pseudo tty. */
736 /* Enter interactive session. */
737 s->ptymaster = ptymaster;
738 packet_set_interactive(1);
740 session_set_fds(s, ptyfd, fdout, -1, 1);
742 server_loop(pid, ptyfd, fdout, -1);
743 /* server_loop _has_ closed ptyfd and fdout. */
748 #ifdef LOGIN_NEEDS_UTMPX
750 do_pre_login(Session *s)
753 struct sockaddr_storage from;
754 pid_t pid = getpid();
757 * Get IP address of client. If the connection is not a socket, let
758 * the address be 0.0.0.0.
760 memset(&from, 0, sizeof(from));
761 fromlen = sizeof(from);
762 if (packet_connection_is_on_socket()) {
763 if (getpeername(packet_get_connection_in(),
764 (struct sockaddr *)&from, &fromlen) < 0) {
765 debug("getpeername: %.100s", strerror(errno));
770 record_utmp_only(pid, s->tty, s->pw->pw_name,
771 get_remote_name_or_ip(utmp_len, options.use_dns),
772 (struct sockaddr *)&from, fromlen);
777 * This is called to fork and execute a command. If another command is
778 * to be forced, execute that instead.
781 do_exec(Session *s, const char *command)
785 if (options.adm_forced_command) {
786 original_command = command;
787 command = options.adm_forced_command;
788 if (IS_INTERNAL_SFTP(command))
789 s->is_subsystem = SUBSYSTEM_INT_SFTP;
790 else if (s->is_subsystem)
791 s->is_subsystem = SUBSYSTEM_EXT;
792 debug("Forced command (config) '%.900s'", command);
793 } else if (forced_command) {
794 original_command = command;
795 command = forced_command;
796 if (IS_INTERNAL_SFTP(command))
797 s->is_subsystem = SUBSYSTEM_INT_SFTP;
798 else if (s->is_subsystem)
799 s->is_subsystem = SUBSYSTEM_EXT;
800 debug("Forced command (key option) '%.900s'", command);
803 #ifdef SSH_AUDIT_EVENTS
805 PRIVSEP(audit_run_command(command));
806 else if (s->ttyfd == -1) {
807 char *shell = s->pw->pw_shell;
809 if (shell[0] == '\0') /* empty shell means /bin/sh */
811 PRIVSEP(audit_run_command(shell));
815 ret = do_exec_pty(s, command);
817 ret = do_exec_no_pty(s, command);
819 original_command = NULL;
822 * Clear loginmsg: it's the child's responsibility to display
823 * it to the user, otherwise multiple sessions may accumulate
824 * multiple copies of the login messages.
826 buffer_clear(&loginmsg);
831 /* administrative, login(1)-like work */
833 do_login(Session *s, const char *command)
836 struct sockaddr_storage from;
837 struct passwd * pw = s->pw;
838 pid_t pid = getpid();
841 * Get IP address of client. If the connection is not a socket, let
842 * the address be 0.0.0.0.
844 memset(&from, 0, sizeof(from));
845 fromlen = sizeof(from);
846 if (packet_connection_is_on_socket()) {
847 if (getpeername(packet_get_connection_in(),
848 (struct sockaddr *) & from, &fromlen) < 0) {
849 debug("getpeername: %.100s", strerror(errno));
854 /* Record that there was a login on that tty from the remote host. */
856 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
857 get_remote_name_or_ip(utmp_len,
859 (struct sockaddr *)&from, fromlen);
863 * If password change is needed, do it now.
864 * This needs to occur before the ~/.hushlogin check.
866 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
869 s->authctxt->force_pwchange = 0;
870 /* XXX - signal [net] parent to enable forwardings */
874 if (check_quietlogin(s, command))
883 * Display the message of the day.
891 if (options.print_motd) {
892 #ifdef HAVE_LOGIN_CAP
893 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
896 f = fopen("/etc/motd", "r");
899 while (fgets(buf, sizeof(buf), f))
908 * Check for quiet login, either .hushlogin or command given.
911 check_quietlogin(Session *s, const char *command)
914 struct passwd *pw = s->pw;
917 /* Return 1 if .hushlogin exists or a command given. */
920 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
921 #ifdef HAVE_LOGIN_CAP
922 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
925 if (stat(buf, &st) >= 0)
932 * Sets the value of the given variable in the environment. If the variable
933 * already exists, its value is overridden.
936 child_set_env(char ***envp, u_int *envsizep, const char *name,
944 * If we're passed an uninitialized list, allocate a single null
945 * entry before continuing.
947 if (*envp == NULL && *envsizep == 0) {
948 *envp = xmalloc(sizeof(char *));
954 * Find the slot where the value should be stored. If the variable
955 * already exists, we reuse the slot; otherwise we append a new slot
956 * at the end of the array, expanding if necessary.
959 namelen = strlen(name);
960 for (i = 0; env[i]; i++)
961 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
964 /* Reuse the slot. */
967 /* New variable. Expand if necessary. */
969 if (i >= envsize - 1) {
971 fatal("child_set_env: too many env vars");
973 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
976 /* Need to set the NULL pointer at end of array beyond the new slot. */
980 /* Allocate space and format the variable in the appropriate slot. */
981 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
982 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
986 * Reads environment variables from the given file and adds/overrides them
987 * into the environment. If the file does not exist, this does nothing.
988 * Otherwise, it must consist of empty lines, comments (line starts with '#')
989 * and assignments of the form name=value. No other forms are allowed.
992 read_environment_file(char ***env, u_int *envsize,
993 const char *filename)
1000 f = fopen(filename, "r");
1004 while (fgets(buf, sizeof(buf), f)) {
1005 if (++lineno > 1000)
1006 fatal("Too many lines in environment file %s", filename);
1007 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1009 if (!*cp || *cp == '#' || *cp == '\n')
1012 cp[strcspn(cp, "\n")] = '\0';
1014 value = strchr(cp, '=');
1015 if (value == NULL) {
1016 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1021 * Replace the equals sign by nul, and advance value to
1026 child_set_env(env, envsize, cp, value);
1031 #ifdef HAVE_ETC_DEFAULT_LOGIN
1033 * Return named variable from specified environment, or NULL if not present.
1036 child_get_env(char **env, const char *name)
1042 for (i=0; env[i] != NULL; i++)
1043 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1044 return(env[i] + len + 1);
1049 * Read /etc/default/login.
1050 * We pick up the PATH (or SUPATH for root) and UMASK.
1053 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1055 char **tmpenv = NULL, *var;
1056 u_int i, tmpenvsize = 0;
1060 * We don't want to copy the whole file to the child's environment,
1061 * so we use a temporary environment and copy the variables we're
1064 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1070 var = child_get_env(tmpenv, "SUPATH");
1072 var = child_get_env(tmpenv, "PATH");
1074 child_set_env(env, envsize, "PATH", var);
1076 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1077 if (sscanf(var, "%5lo", &mask) == 1)
1078 umask((mode_t)mask);
1080 for (i = 0; tmpenv[i] != NULL; i++)
1084 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1087 copy_environment(char **source, char ***env, u_int *envsize)
1089 char *var_name, *var_val;
1095 for(i = 0; source[i] != NULL; i++) {
1096 var_name = xstrdup(source[i]);
1097 if ((var_val = strstr(var_name, "=")) == NULL) {
1103 debug3("Copy environment: %s=%s", var_name, var_val);
1104 child_set_env(env, envsize, var_name, var_val);
1111 do_setup_env(Session *s, const char *shell)
1116 struct passwd *pw = s->pw;
1117 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1121 /* Initialize the environment. */
1123 env = xcalloc(envsize, sizeof(char *));
1128 * The Windows environment contains some setting which are
1129 * important for a running system. They must not be dropped.
1134 p = fetch_windows_environment();
1135 copy_environment(p, &env, &envsize);
1136 free_windows_environment(p);
1141 /* Allow any GSSAPI methods that we've used to alter
1142 * the childs environment as they see fit
1144 ssh_gssapi_do_child(&env, &envsize);
1147 if (!options.use_login) {
1148 /* Set basic environment. */
1149 for (i = 0; i < s->num_env; i++)
1150 child_set_env(&env, &envsize, s->env[i].name,
1153 child_set_env(&env, &envsize, "USER", pw->pw_name);
1154 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1156 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1158 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1159 #ifdef HAVE_LOGIN_CAP
1160 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1161 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1163 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1164 #else /* HAVE_LOGIN_CAP */
1165 # ifndef HAVE_CYGWIN
1167 * There's no standard path on Windows. The path contains
1168 * important components pointing to the system directories,
1169 * needed for loading shared libraries. So the path better
1170 * remains intact here.
1172 # ifdef HAVE_ETC_DEFAULT_LOGIN
1173 read_etc_default_login(&env, &envsize, pw->pw_uid);
1174 path = child_get_env(env, "PATH");
1175 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1176 if (path == NULL || *path == '\0') {
1177 child_set_env(&env, &envsize, "PATH",
1178 s->pw->pw_uid == 0 ?
1179 SUPERUSER_PATH : _PATH_STDPATH);
1181 # endif /* HAVE_CYGWIN */
1182 #endif /* HAVE_LOGIN_CAP */
1184 snprintf(buf, sizeof buf, "%.200s/%.50s",
1185 _PATH_MAILDIR, pw->pw_name);
1186 child_set_env(&env, &envsize, "MAIL", buf);
1188 /* Normal systems set SHELL by default. */
1189 child_set_env(&env, &envsize, "SHELL", shell);
1192 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1194 /* Set custom environment options from RSA authentication. */
1195 if (!options.use_login) {
1196 while (custom_environment) {
1197 struct envstring *ce = custom_environment;
1200 for (i = 0; str[i] != '=' && str[i]; i++)
1202 if (str[i] == '=') {
1204 child_set_env(&env, &envsize, str, str + i + 1);
1206 custom_environment = ce->next;
1212 /* SSH_CLIENT deprecated */
1213 snprintf(buf, sizeof buf, "%.50s %d %d",
1214 get_remote_ipaddr(), get_remote_port(), get_local_port());
1215 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1217 laddr = get_local_ipaddr(packet_get_connection_in());
1218 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1219 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1221 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1224 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1226 child_set_env(&env, &envsize, "TERM", s->term);
1228 child_set_env(&env, &envsize, "DISPLAY", s->display);
1229 if (original_command)
1230 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1234 if (cray_tmpdir[0] != '\0')
1235 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1236 #endif /* _UNICOS */
1239 * Since we clear KRB5CCNAME at startup, if it's set now then it
1240 * must have been set by a native authentication method (eg AIX or
1241 * SIA), so copy it to the child.
1246 if ((cp = getenv("KRB5CCNAME")) != NULL)
1247 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1254 if ((cp = getenv("AUTHSTATE")) != NULL)
1255 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1256 read_environment_file(&env, &envsize, "/etc/environment");
1260 if (s->authctxt->krb5_ccname)
1261 child_set_env(&env, &envsize, "KRB5CCNAME",
1262 s->authctxt->krb5_ccname);
1266 * Pull in any environment variables that may have
1269 if (options.use_pam) {
1272 p = fetch_pam_child_environment();
1273 copy_environment(p, &env, &envsize);
1274 free_pam_environment(p);
1276 p = fetch_pam_environment();
1277 copy_environment(p, &env, &envsize);
1278 free_pam_environment(p);
1280 #endif /* USE_PAM */
1282 if (auth_sock_name != NULL)
1283 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1286 /* read $HOME/.ssh/environment. */
1287 if (options.permit_user_env && !options.use_login) {
1288 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1289 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1290 read_environment_file(&env, &envsize, buf);
1293 /* dump the environment */
1294 fprintf(stderr, "Environment:\n");
1295 for (i = 0; env[i]; i++)
1296 fprintf(stderr, " %.200s\n", env[i]);
1302 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1303 * first in this order).
1306 do_rc_files(Session *s, const char *shell)
1314 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1316 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1317 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1318 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1319 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1320 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1322 fprintf(stderr, "Running %s\n", cmd);
1323 f = popen(cmd, "w");
1326 fprintf(f, "%s %s\n", s->auth_proto,
1330 fprintf(stderr, "Could not run %s\n",
1332 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1334 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1335 _PATH_SSH_SYSTEM_RC);
1336 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1339 fprintf(f, "%s %s\n", s->auth_proto,
1343 fprintf(stderr, "Could not run %s\n",
1344 _PATH_SSH_SYSTEM_RC);
1345 } else if (do_xauth && options.xauth_location != NULL) {
1346 /* Add authority data to .Xauthority if appropriate. */
1349 "Running %.500s remove %.100s\n",
1350 options.xauth_location, s->auth_display);
1352 "%.500s add %.100s %.100s %.100s\n",
1353 options.xauth_location, s->auth_display,
1354 s->auth_proto, s->auth_data);
1356 snprintf(cmd, sizeof cmd, "%s -q -",
1357 options.xauth_location);
1358 f = popen(cmd, "w");
1360 fprintf(f, "remove %s\n",
1362 fprintf(f, "add %s %s %s\n",
1363 s->auth_display, s->auth_proto,
1367 fprintf(stderr, "Could not run %s\n",
1374 do_nologin(struct passwd *pw)
1379 #ifdef HAVE_LOGIN_CAP
1380 if (!login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1381 f = fopen(login_getcapstr(lc, "nologin", _PATH_NOLOGIN,
1382 _PATH_NOLOGIN), "r");
1385 f = fopen(_PATH_NOLOGIN, "r");
1388 /* /etc/nologin exists. Print its contents and exit. */
1389 logit("User %.100s not allowed because %s exists",
1390 pw->pw_name, _PATH_NOLOGIN);
1391 while (fgets(buf, sizeof(buf), f))
1400 * Chroot into a directory after checking it for safety: all path components
1401 * must be root-owned directories with strict permissions.
1404 safely_chroot(const char *path, uid_t uid)
1407 char component[MAXPATHLEN];
1411 fatal("chroot path does not begin at root");
1412 if (strlen(path) >= sizeof(component))
1413 fatal("chroot path too long");
1416 * Descend the path, checking that each component is a
1417 * root-owned directory with strict permissions.
1419 for (cp = path; cp != NULL;) {
1420 if ((cp = strchr(cp, '/')) == NULL)
1421 strlcpy(component, path, sizeof(component));
1424 memcpy(component, path, cp - path);
1425 component[cp - path] = '\0';
1428 debug3("%s: checking '%s'", __func__, component);
1430 if (stat(component, &st) != 0)
1431 fatal("%s: stat(\"%s\"): %s", __func__,
1432 component, strerror(errno));
1433 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1434 fatal("bad ownership or modes for chroot "
1435 "directory %s\"%s\"",
1436 cp == NULL ? "" : "component ", component);
1437 if (!S_ISDIR(st.st_mode))
1438 fatal("chroot path %s\"%s\" is not a directory",
1439 cp == NULL ? "" : "component ", component);
1443 if (chdir(path) == -1)
1444 fatal("Unable to chdir to chroot path \"%s\": "
1445 "%s", path, strerror(errno));
1446 if (chroot(path) == -1)
1447 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1448 if (chdir("/") == -1)
1449 fatal("%s: chdir(/) after chroot: %s",
1450 __func__, strerror(errno));
1451 verbose("Changed root directory to \"%s\"", path);
1454 /* Set login name, uid, gid, and groups. */
1456 do_setusercontext(struct passwd *pw)
1458 char *chroot_path, *tmp;
1461 /* Cache selinux status for later use */
1462 (void)ssh_selinux_enabled();
1466 if (getuid() == 0 || geteuid() == 0)
1467 #endif /* HAVE_CYGWIN */
1470 #ifdef HAVE_SETPCRED
1471 if (setpcred(pw->pw_name, (char **)NULL) == -1)
1472 fatal("Failed to set process credentials");
1473 #endif /* HAVE_SETPCRED */
1474 #ifdef HAVE_LOGIN_CAP
1479 if (options.use_pam) {
1480 do_pam_setcred(use_privsep);
1482 # endif /* USE_PAM */
1483 if (setusercontext(lc, pw, pw->pw_uid,
1484 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1485 perror("unable to set user context");
1489 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1490 /* Sets login uid for accounting */
1491 if (getluid() == -1 && setluid(pw->pw_uid) == -1)
1492 error("setluid: %s", strerror(errno));
1493 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1495 if (setlogin(pw->pw_name) < 0)
1496 error("setlogin failed: %s", strerror(errno));
1497 if (setgid(pw->pw_gid) < 0) {
1501 /* Initialize the group list. */
1502 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1503 perror("initgroups");
1509 * PAM credentials may take the form of supplementary groups.
1510 * These will have been wiped by the above initgroups() call.
1511 * Reestablish them here.
1513 if (options.use_pam) {
1514 do_pam_setcred(use_privsep);
1516 # endif /* USE_PAM */
1517 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1518 irix_setusercontext(pw);
1519 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1524 if (set_id(pw->pw_name) != 0) {
1527 # endif /* USE_LIBIAF */
1530 if (options.chroot_directory != NULL &&
1531 strcasecmp(options.chroot_directory, "none") != 0) {
1532 tmp = tilde_expand_filename(options.chroot_directory,
1534 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1535 "u", pw->pw_name, (char *)NULL);
1536 safely_chroot(chroot_path, pw->pw_uid);
1541 #ifdef HAVE_LOGIN_CAP
1542 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1543 perror("unable to set user context (setuser)");
1547 /* Permanently switch to the desired uid. */
1548 permanently_set_uid(pw);
1552 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1553 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1556 ssh_selinux_setup_exec_context(pw->pw_name);
1561 do_pwchange(Session *s)
1564 fprintf(stderr, "WARNING: Your password has expired.\n");
1565 if (s->ttyfd != -1) {
1567 "You must change your password now and login again!\n");
1568 #ifdef PASSWD_NEEDS_USERNAME
1569 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1572 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1577 "Password change required but no TTY available.\n");
1583 launch_login(struct passwd *pw, const char *hostname)
1585 /* Launch login(1). */
1587 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1588 #ifdef xxxLOGIN_NEEDS_TERM
1589 (s->term ? s->term : "unknown"),
1590 #endif /* LOGIN_NEEDS_TERM */
1591 #ifdef LOGIN_NO_ENDOPT
1592 "-p", "-f", pw->pw_name, (char *)NULL);
1594 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1597 /* Login couldn't be executed, die. */
1604 child_close_fds(void)
1608 if (packet_get_connection_in() == packet_get_connection_out())
1609 close(packet_get_connection_in());
1611 close(packet_get_connection_in());
1612 close(packet_get_connection_out());
1615 * Close all descriptors related to channels. They will still remain
1616 * open in the parent.
1618 /* XXX better use close-on-exec? -markus */
1619 channel_close_all();
1622 * Close any extra file descriptors. Note that there may still be
1623 * descriptors left by system functions. They will be closed later.
1628 * Close any extra open file descriptors so that we don't have them
1629 * hanging around in clients. Note that we want to do this after
1630 * initgroups, because at least on Solaris 2.3 it leaves file
1633 for (i = 3; i < 64; i++)
1638 * Performs common processing for the child, such as setting up the
1639 * environment, closing extra file descriptors, setting the user and group
1640 * ids, and executing the command or shell.
1644 do_child(Session *s, const char *command)
1646 extern char **environ;
1648 char *argv[ARGV_MAX];
1649 const char *shell, *shell0, *hostname = NULL;
1650 struct passwd *pw = s->pw;
1653 /* remove hostkey from the child's memory */
1654 destroy_sensitive_data();
1656 /* Force a password change */
1657 if (s->authctxt->force_pwchange) {
1658 do_setusercontext(pw);
1664 /* login(1) is only called if we execute the login shell */
1665 if (options.use_login && command != NULL)
1666 options.use_login = 0;
1669 cray_setup(pw->pw_uid, pw->pw_name, command);
1670 #endif /* _UNICOS */
1673 * Login(1) does this as well, and it needs uid 0 for the "-h"
1674 * switch, so we let login(1) to this for us.
1676 if (!options.use_login) {
1678 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1679 if (!check_quietlogin(s, command))
1681 #else /* HAVE_OSF_SIA */
1682 /* When PAM is enabled we rely on it to do the nologin check */
1683 if (!options.use_pam)
1685 do_setusercontext(pw);
1687 * PAM session modules in do_setusercontext may have
1688 * generated messages, so if this in an interactive
1689 * login then display them too.
1691 if (!check_quietlogin(s, command))
1693 #endif /* HAVE_OSF_SIA */
1697 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1698 debug3("PAM session not opened, exiting");
1705 * Get the shell from the password data. An empty shell field is
1706 * legal, and means /bin/sh.
1708 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1711 * Make sure $SHELL points to the shell from the password file,
1712 * even if shell is overridden from login.conf
1714 env = do_setup_env(s, shell);
1716 #ifdef HAVE_LOGIN_CAP
1717 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1720 /* we have to stash the hostname before we close our socket. */
1721 if (options.use_login)
1722 hostname = get_remote_name_or_ip(utmp_len,
1725 * Close the connection descriptors; note that this is the child, and
1726 * the server will still have the socket open, and it is important
1727 * that we do not shutdown it. Note that the descriptors cannot be
1728 * closed before building the environment, as we call
1729 * get_remote_ipaddr there.
1734 * Must take new environment into use so that .ssh/rc,
1735 * /etc/ssh/sshrc and xauth are run in the proper environment.
1739 #if defined(KRB5) && defined(USE_AFS)
1741 * At this point, we check to see if AFS is active and if we have
1742 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1743 * if we can (and need to) extend the ticket into an AFS token. If
1744 * we don't do this, we run into potential problems if the user's
1745 * home directory is in AFS and it's not world-readable.
1748 if (options.kerberos_get_afs_token && k_hasafs() &&
1749 (s->authctxt->krb5_ctx != NULL)) {
1752 debug("Getting AFS token");
1756 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1757 krb5_afslog(s->authctxt->krb5_ctx,
1758 s->authctxt->krb5_fwd_ccache, cell, NULL);
1760 krb5_afslog_home(s->authctxt->krb5_ctx,
1761 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1765 /* Change current directory to the user's home directory. */
1766 if (chdir(pw->pw_dir) < 0) {
1767 /* Suppress missing homedir warning for chroot case */
1768 #ifdef HAVE_LOGIN_CAP
1769 r = login_getcapbool(lc, "requirehome", 0);
1771 if (r || options.chroot_directory == NULL)
1772 fprintf(stderr, "Could not chdir to home "
1773 "directory %s: %s\n", pw->pw_dir,
1779 closefrom(STDERR_FILENO + 1);
1781 if (!options.use_login)
1782 do_rc_files(s, shell);
1784 /* restore SIGPIPE for child */
1785 signal(SIGPIPE, SIG_DFL);
1787 if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1788 extern int optind, optreset;
1792 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1793 args = xstrdup(command ? command : "sftp-server");
1794 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1795 if (i < ARGV_MAX - 1)
1798 optind = optreset = 1;
1799 __progname = argv[0];
1800 exit(sftp_server_main(i, argv, s->pw));
1803 if (options.use_login) {
1804 launch_login(pw, hostname);
1808 /* Get the last component of the shell name. */
1809 if ((shell0 = strrchr(shell, '/')) != NULL)
1815 * If we have no command, execute the shell. In this case, the shell
1816 * name to be passed in argv[0] is preceded by '-' to indicate that
1817 * this is a login shell.
1822 /* Start the shell. Set initial character to '-'. */
1825 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1826 >= sizeof(argv0) - 1) {
1832 /* Execute the shell. */
1835 execve(shell, argv, env);
1837 /* Executing the shell failed. */
1842 * Execute the command using the user's shell. This uses the -c
1843 * option to execute the command.
1845 argv[0] = (char *) shell0;
1847 argv[2] = (char *) command;
1849 execve(shell, argv, env);
1855 session_unused(int id)
1857 debug3("%s: session id %d unused", __func__, id);
1858 if (id >= options.max_sessions ||
1859 id >= sessions_nalloc) {
1860 fatal("%s: insane session id %d (max %d nalloc %d)",
1861 __func__, id, options.max_sessions, sessions_nalloc);
1863 bzero(&sessions[id], sizeof(*sessions));
1864 sessions[id].self = id;
1865 sessions[id].used = 0;
1866 sessions[id].chanid = -1;
1867 sessions[id].ptyfd = -1;
1868 sessions[id].ttyfd = -1;
1869 sessions[id].ptymaster = -1;
1870 sessions[id].x11_chanids = NULL;
1871 sessions[id].next_unused = sessions_first_unused;
1872 sessions_first_unused = id;
1880 if (sessions_first_unused == -1) {
1881 if (sessions_nalloc >= options.max_sessions)
1883 debug2("%s: allocate (allocated %d max %d)",
1884 __func__, sessions_nalloc, options.max_sessions);
1885 tmp = xrealloc(sessions, sessions_nalloc + 1,
1888 error("%s: cannot allocate %d sessions",
1889 __func__, sessions_nalloc + 1);
1893 session_unused(sessions_nalloc++);
1896 if (sessions_first_unused >= sessions_nalloc ||
1897 sessions_first_unused < 0) {
1898 fatal("%s: insane first_unused %d max %d nalloc %d",
1899 __func__, sessions_first_unused, options.max_sessions,
1903 s = &sessions[sessions_first_unused];
1905 fatal("%s: session %d already used",
1906 __func__, sessions_first_unused);
1908 sessions_first_unused = s->next_unused;
1910 s->next_unused = -1;
1911 debug("session_new: session %d", s->self);
1920 for (i = 0; i < sessions_nalloc; i++) {
1921 Session *s = &sessions[i];
1923 debug("dump: used %d next_unused %d session %d %p "
1924 "channel %d pid %ld",
1935 session_open(Authctxt *authctxt, int chanid)
1937 Session *s = session_new();
1938 debug("session_open: channel %d", chanid);
1940 error("no more sessions");
1943 s->authctxt = authctxt;
1944 s->pw = authctxt->pw;
1945 if (s->pw == NULL || !authctxt->valid)
1946 fatal("no user for session %d", s->self);
1947 debug("session_open: session %d: link with channel %d", s->self, chanid);
1953 session_by_tty(char *tty)
1956 for (i = 0; i < sessions_nalloc; i++) {
1957 Session *s = &sessions[i];
1958 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1959 debug("session_by_tty: session %d tty %s", i, tty);
1963 debug("session_by_tty: unknown tty %.100s", tty);
1969 session_by_channel(int id)
1972 for (i = 0; i < sessions_nalloc; i++) {
1973 Session *s = &sessions[i];
1974 if (s->used && s->chanid == id) {
1975 debug("session_by_channel: session %d channel %d",
1980 debug("session_by_channel: unknown channel %d", id);
1986 session_by_x11_channel(int id)
1990 for (i = 0; i < sessions_nalloc; i++) {
1991 Session *s = &sessions[i];
1993 if (s->x11_chanids == NULL || !s->used)
1995 for (j = 0; s->x11_chanids[j] != -1; j++) {
1996 if (s->x11_chanids[j] == id) {
1997 debug("session_by_x11_channel: session %d "
1998 "channel %d", s->self, id);
2003 debug("session_by_x11_channel: unknown channel %d", id);
2009 session_by_pid(pid_t pid)
2012 debug("session_by_pid: pid %ld", (long)pid);
2013 for (i = 0; i < sessions_nalloc; i++) {
2014 Session *s = &sessions[i];
2015 if (s->used && s->pid == pid)
2018 error("session_by_pid: unknown pid %ld", (long)pid);
2024 session_window_change_req(Session *s)
2026 s->col = packet_get_int();
2027 s->row = packet_get_int();
2028 s->xpixel = packet_get_int();
2029 s->ypixel = packet_get_int();
2031 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2036 session_pty_req(Session *s)
2042 debug("Allocating a pty not permitted for this authentication.");
2045 if (s->ttyfd != -1) {
2046 packet_disconnect("Protocol error: you already have a pty.");
2050 s->term = packet_get_string(&len);
2053 s->col = packet_get_int();
2054 s->row = packet_get_int();
2056 s->row = packet_get_int();
2057 s->col = packet_get_int();
2059 s->xpixel = packet_get_int();
2060 s->ypixel = packet_get_int();
2062 if (strcmp(s->term, "") == 0) {
2067 /* Allocate a pty and open it. */
2068 debug("Allocating pty.");
2069 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2076 error("session_pty_req: session %d alloc failed", s->self);
2079 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2081 /* for SSH1 the tty modes length is not given */
2083 n_bytes = packet_remaining();
2084 tty_parse_modes(s->ttyfd, &n_bytes);
2087 pty_setowner(s->pw, s->tty);
2089 /* Set window size from the packet. */
2090 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2093 session_proctitle(s);
2098 session_subsystem_req(Session *s)
2103 char *prog, *cmd, *subsys = packet_get_string(&len);
2107 logit("subsystem request for %.100s", subsys);
2109 for (i = 0; i < options.num_subsystems; i++) {
2110 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2111 prog = options.subsystem_command[i];
2112 cmd = options.subsystem_args[i];
2113 if (!strcmp(INTERNAL_SFTP_NAME, prog)) {
2114 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2115 } else if (stat(prog, &st) < 0) {
2116 error("subsystem: cannot stat %s: %s", prog,
2120 s->is_subsystem = SUBSYSTEM_EXT;
2122 debug("subsystem: exec() %s", cmd);
2123 success = do_exec(s, cmd) == 0;
2129 logit("subsystem request for %.100s failed, subsystem not found",
2137 session_x11_req(Session *s)
2141 if (s->auth_proto != NULL || s->auth_data != NULL) {
2142 error("session_x11_req: session %d: "
2143 "x11 forwarding already active", s->self);
2146 s->single_connection = packet_get_char();
2147 s->auth_proto = packet_get_string(NULL);
2148 s->auth_data = packet_get_string(NULL);
2149 s->screen = packet_get_int();
2152 success = session_setup_x11fwd(s);
2154 xfree(s->auth_proto);
2155 xfree(s->auth_data);
2156 s->auth_proto = NULL;
2157 s->auth_data = NULL;
2163 session_shell_req(Session *s)
2166 return do_exec(s, NULL) == 0;
2170 session_exec_req(Session *s)
2174 char *command = packet_get_string(&len);
2176 success = do_exec(s, command) == 0;
2182 session_break_req(Session *s)
2185 packet_get_int(); /* ignored */
2188 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
2194 session_env_req(Session *s)
2197 u_int name_len, val_len, i;
2199 name = packet_get_string(&name_len);
2200 val = packet_get_string(&val_len);
2203 /* Don't set too many environment variables */
2204 if (s->num_env > 128) {
2205 debug2("Ignoring env request %s: too many env vars", name);
2209 for (i = 0; i < options.num_accept_env; i++) {
2210 if (match_pattern(name, options.accept_env[i])) {
2211 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2212 s->env = xrealloc(s->env, s->num_env + 1,
2214 s->env[s->num_env].name = name;
2215 s->env[s->num_env].val = val;
2220 debug2("Ignoring env request %s: disallowed name", name);
2229 session_auth_agent_req(Session *s)
2231 static int called = 0;
2233 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2234 debug("session_auth_agent_req: no_agent_forwarding_flag");
2241 return auth_input_request_forwarding(s->pw);
2246 session_input_channel_req(Channel *c, const char *rtype)
2251 if ((s = session_by_channel(c->self)) == NULL) {
2252 logit("session_input_channel_req: no session %d req %.100s",
2256 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2259 * a session is in LARVAL state until a shell, a command
2260 * or a subsystem is executed
2262 if (c->type == SSH_CHANNEL_LARVAL) {
2263 if (strcmp(rtype, "shell") == 0) {
2264 success = session_shell_req(s);
2265 } else if (strcmp(rtype, "exec") == 0) {
2266 success = session_exec_req(s);
2267 } else if (strcmp(rtype, "pty-req") == 0) {
2268 success = session_pty_req(s);
2269 } else if (strcmp(rtype, "x11-req") == 0) {
2270 success = session_x11_req(s);
2271 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2272 success = session_auth_agent_req(s);
2273 } else if (strcmp(rtype, "subsystem") == 0) {
2274 success = session_subsystem_req(s);
2275 } else if (strcmp(rtype, "env") == 0) {
2276 success = session_env_req(s);
2279 if (strcmp(rtype, "window-change") == 0) {
2280 success = session_window_change_req(s);
2281 } else if (strcmp(rtype, "break") == 0) {
2282 success = session_break_req(s);
2289 session_set_fds(Session *s, int fdin, int fdout, int fderr, int is_tty)
2292 fatal("session_set_fds: called for proto != 2.0");
2294 * now that have a child and a pipe to the child,
2295 * we can activate our channel and register the fd's
2297 if (s->chanid == -1)
2298 fatal("no channel for session %d", s->self);
2299 channel_set_fds(s->chanid,
2301 fderr == -1 ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2302 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2306 * Function to perform pty cleanup. Also called if we get aborted abnormally
2307 * (e.g., due to a dropped connection).
2310 session_pty_cleanup2(Session *s)
2313 error("session_pty_cleanup: no session");
2319 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2321 /* Record that the user has logged out. */
2323 record_logout(s->pid, s->tty, s->pw->pw_name);
2325 /* Release the pseudo-tty. */
2327 pty_release(s->tty);
2330 * Close the server side of the socket pairs. We must do this after
2331 * the pty cleanup, so that another process doesn't get this pty
2332 * while we're still cleaning up.
2334 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2335 error("close(s->ptymaster/%d): %s",
2336 s->ptymaster, strerror(errno));
2338 /* unlink pty from session */
2343 session_pty_cleanup(Session *s)
2345 PRIVSEP(session_pty_cleanup2(s));
2351 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2366 return "SIG@openssh.com";
2370 session_close_x11(int id)
2374 if ((c = channel_by_id(id)) == NULL) {
2375 debug("session_close_x11: x11 channel %d missing", id);
2377 /* Detach X11 listener */
2378 debug("session_close_x11: detach x11 channel %d", id);
2379 channel_cancel_cleanup(id);
2380 if (c->ostate != CHAN_OUTPUT_CLOSED)
2386 session_close_single_x11(int id, void *arg)
2391 debug3("session_close_single_x11: channel %d", id);
2392 channel_cancel_cleanup(id);
2393 if ((s = session_by_x11_channel(id)) == NULL)
2394 fatal("session_close_single_x11: no x11 channel %d", id);
2395 for (i = 0; s->x11_chanids[i] != -1; i++) {
2396 debug("session_close_single_x11: session %d: "
2397 "closing channel %d", s->self, s->x11_chanids[i]);
2399 * The channel "id" is already closing, but make sure we
2400 * close all of its siblings.
2402 if (s->x11_chanids[i] != id)
2403 session_close_x11(s->x11_chanids[i]);
2405 xfree(s->x11_chanids);
2406 s->x11_chanids = NULL;
2411 if (s->auth_proto) {
2412 xfree(s->auth_proto);
2413 s->auth_proto = NULL;
2416 xfree(s->auth_data);
2417 s->auth_data = NULL;
2419 if (s->auth_display) {
2420 xfree(s->auth_display);
2421 s->auth_display = NULL;
2426 session_exit_message(Session *s, int status)
2430 if ((c = channel_lookup(s->chanid)) == NULL)
2431 fatal("session_exit_message: session %d: no channel %d",
2432 s->self, s->chanid);
2433 debug("session_exit_message: session %d channel %d pid %ld",
2434 s->self, s->chanid, (long)s->pid);
2436 if (WIFEXITED(status)) {
2437 channel_request_start(s->chanid, "exit-status", 0);
2438 packet_put_int(WEXITSTATUS(status));
2440 } else if (WIFSIGNALED(status)) {
2441 channel_request_start(s->chanid, "exit-signal", 0);
2442 packet_put_cstring(sig2name(WTERMSIG(status)));
2444 packet_put_char(WCOREDUMP(status)? 1 : 0);
2445 #else /* WCOREDUMP */
2447 #endif /* WCOREDUMP */
2448 packet_put_cstring("");
2449 packet_put_cstring("");
2452 /* Some weird exit cause. Just exit. */
2453 packet_disconnect("wait returned status %04x.", status);
2456 /* disconnect channel */
2457 debug("session_exit_message: release channel %d", s->chanid);
2460 * Adjust cleanup callback attachment to send close messages when
2461 * the channel gets EOF. The session will be then be closed
2462 * by session_close_by_channel when the childs close their fds.
2464 channel_register_cleanup(c->self, session_close_by_channel, 1);
2467 * emulate a write failure with 'chan_write_failed', nobody will be
2468 * interested in data we write.
2469 * Note that we must not call 'chan_read_failed', since there could
2470 * be some more data waiting in the pipe.
2472 if (c->ostate != CHAN_OUTPUT_CLOSED)
2473 chan_write_failed(c);
2477 session_close(Session *s)
2481 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2483 session_pty_cleanup(s);
2489 xfree(s->x11_chanids);
2490 if (s->auth_display)
2491 xfree(s->auth_display);
2493 xfree(s->auth_data);
2495 xfree(s->auth_proto);
2496 if (s->env != NULL) {
2497 for (i = 0; i < s->num_env; i++) {
2498 xfree(s->env[i].name);
2499 xfree(s->env[i].val);
2503 session_proctitle(s);
2504 session_unused(s->self);
2508 session_close_by_pid(pid_t pid, int status)
2510 Session *s = session_by_pid(pid);
2512 debug("session_close_by_pid: no session for pid %ld",
2516 if (s->chanid != -1)
2517 session_exit_message(s, status);
2519 session_pty_cleanup(s);
2524 * this is called when a channel dies before
2525 * the session 'child' itself dies
2528 session_close_by_channel(int id, void *arg)
2530 Session *s = session_by_channel(id);
2534 debug("session_close_by_channel: no session for id %d", id);
2537 debug("session_close_by_channel: channel %d child %ld",
2540 debug("session_close_by_channel: channel %d: has child", id);
2542 * delay detach of session, but release pty, since
2543 * the fd's to the child are already closed
2546 session_pty_cleanup(s);
2549 /* detach by removing callback */
2550 channel_cancel_cleanup(s->chanid);
2552 /* Close any X11 listeners associated with this session */
2553 if (s->x11_chanids != NULL) {
2554 for (i = 0; s->x11_chanids[i] != -1; i++) {
2555 session_close_x11(s->x11_chanids[i]);
2556 s->x11_chanids[i] = -1;
2565 session_destroy_all(void (*closefunc)(Session *))
2568 for (i = 0; i < sessions_nalloc; i++) {
2569 Session *s = &sessions[i];
2571 if (closefunc != NULL)
2580 session_tty_list(void)
2582 static char buf[1024];
2587 for (i = 0; i < sessions_nalloc; i++) {
2588 Session *s = &sessions[i];
2589 if (s->used && s->ttyfd != -1) {
2591 if (strncmp(s->tty, "/dev/", 5) != 0) {
2592 cp = strrchr(s->tty, '/');
2593 cp = (cp == NULL) ? s->tty : cp + 1;
2598 strlcat(buf, ",", sizeof buf);
2599 strlcat(buf, cp, sizeof buf);
2603 strlcpy(buf, "notty", sizeof buf);
2608 session_proctitle(Session *s)
2611 error("no user for session %d", s->self);
2613 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2617 session_setup_x11fwd(Session *s)
2620 char display[512], auth_display[512];
2621 char hostname[MAXHOSTNAMELEN];
2624 if (no_x11_forwarding_flag) {
2625 packet_send_debug("X11 forwarding disabled in user configuration file.");
2628 if (!options.x11_forwarding) {
2629 debug("X11 forwarding disabled in server configuration file.");
2632 if (!options.xauth_location ||
2633 (stat(options.xauth_location, &st) == -1)) {
2634 packet_send_debug("No xauth program; cannot forward with spoofing.");
2637 if (options.use_login) {
2638 packet_send_debug("X11 forwarding disabled; "
2639 "not compatible with UseLogin=yes.");
2642 if (s->display != NULL) {
2643 debug("X11 display already set.");
2646 if (x11_create_display_inet(options.x11_display_offset,
2647 options.x11_use_localhost, s->single_connection,
2648 &s->display_number, &s->x11_chanids) == -1) {
2649 debug("x11_create_display_inet failed.");
2652 for (i = 0; s->x11_chanids[i] != -1; i++) {
2653 channel_register_cleanup(s->x11_chanids[i],
2654 session_close_single_x11, 0);
2657 /* Set up a suitable value for the DISPLAY variable. */
2658 if (gethostname(hostname, sizeof(hostname)) < 0)
2659 fatal("gethostname: %.100s", strerror(errno));
2661 * auth_display must be used as the displayname when the
2662 * authorization entry is added with xauth(1). This will be
2663 * different than the DISPLAY string for localhost displays.
2665 if (options.x11_use_localhost) {
2666 snprintf(display, sizeof display, "localhost:%u.%u",
2667 s->display_number, s->screen);
2668 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2669 s->display_number, s->screen);
2670 s->display = xstrdup(display);
2671 s->auth_display = xstrdup(auth_display);
2673 #ifdef IPADDR_IN_DISPLAY
2675 struct in_addr my_addr;
2677 he = gethostbyname(hostname);
2679 error("Can't get IP address for X11 DISPLAY.");
2680 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2683 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2684 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2685 s->display_number, s->screen);
2687 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2688 s->display_number, s->screen);
2690 s->display = xstrdup(display);
2691 s->auth_display = xstrdup(display);
2698 do_authenticated2(Authctxt *authctxt)
2700 server_loop2(authctxt);
2704 do_cleanup(Authctxt *authctxt)
2706 static int called = 0;
2708 debug("do_cleanup");
2710 /* no cleanup if we're in the child for login shell */
2714 /* avoid double cleanup */
2719 if (authctxt == NULL)
2723 if (options.use_pam) {
2725 sshpam_thread_cleanup();
2729 if (!authctxt->authenticated)
2733 if (options.kerberos_ticket_cleanup &&
2735 krb5_cleanup_proc(authctxt);
2739 if (compat20 && options.gss_cleanup_creds)
2740 ssh_gssapi_cleanup_creds();
2743 /* remove agent socket */
2744 auth_sock_cleanup_proc(authctxt->pw);
2747 * Cleanup ptys/utmp only if privsep is disabled,
2748 * or if running in monitor.
2750 if (!use_privsep || mm_is_monitor())
2751 session_destroy_all(session_pty_cleanup2);