1 /* $OpenBSD: session.c,v 1.258 2010/11/25 04:10:09 djm 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>
63 #include "openbsd-compat/sys-queue.h"
82 #include "auth-options.h"
83 #include "pathnames.h"
87 #include "serverloop.h"
92 #include "monitor_wrap.h"
95 #if defined(KRB5) && defined(USE_AFS)
100 #include <selinux/selinux.h>
103 #define IS_INTERNAL_SFTP(c) \
104 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
105 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
106 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
107 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
111 Session *session_new(void);
112 void session_set_fds(Session *, int, int, int, int, int);
113 void session_pty_cleanup(Session *);
114 void session_proctitle(Session *);
115 int session_setup_x11fwd(Session *);
116 int do_exec_pty(Session *, const char *);
117 int do_exec_no_pty(Session *, const char *);
118 int do_exec(Session *, const char *);
119 void do_login(Session *, const char *);
120 #ifdef LOGIN_NEEDS_UTMPX
121 static void do_pre_login(Session *s);
123 void do_child(Session *, const char *);
125 int check_quietlogin(Session *, const char *);
127 static void do_authenticated1(Authctxt *);
128 static void do_authenticated2(Authctxt *);
130 static int session_pty_req(Session *);
133 extern ServerOptions options;
134 extern char *__progname;
135 extern int log_stderr;
136 extern int debug_flag;
137 extern u_int utmp_len;
138 extern int startup_pipe;
139 extern void destroy_sensitive_data(void);
140 extern Buffer loginmsg;
142 /* original command from peer. */
143 const char *original_command = NULL;
146 static int sessions_first_unused = -1;
147 static int sessions_nalloc = 0;
148 static Session *sessions = NULL;
150 #define SUBSYSTEM_NONE 0
151 #define SUBSYSTEM_EXT 1
152 #define SUBSYSTEM_INT_SFTP 2
153 #define SUBSYSTEM_INT_SFTP_ERROR 3
155 #ifdef HAVE_LOGIN_CAP
159 static int is_child = 0;
161 /* Name and directory of socket for authentication agent forwarding. */
162 static char *auth_sock_name = NULL;
163 static char *auth_sock_dir = NULL;
165 /* removes the agent forwarding socket */
168 auth_sock_cleanup_proc(struct passwd *pw)
170 if (auth_sock_name != NULL) {
171 temporarily_use_uid(pw);
172 unlink(auth_sock_name);
173 rmdir(auth_sock_dir);
174 auth_sock_name = NULL;
180 auth_input_request_forwarding(struct passwd * pw)
184 struct sockaddr_un sunaddr;
186 if (auth_sock_name != NULL) {
187 error("authentication forwarding requested twice.");
191 /* Temporarily drop privileged uid for mkdir/bind. */
192 temporarily_use_uid(pw);
194 /* Allocate a buffer for the socket name, and format the name. */
195 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
197 /* Create private directory for socket */
198 if (mkdtemp(auth_sock_dir) == NULL) {
199 packet_send_debug("Agent forwarding disabled: "
200 "mkdtemp() failed: %.100s", strerror(errno));
202 xfree(auth_sock_dir);
203 auth_sock_dir = NULL;
207 xasprintf(&auth_sock_name, "%s/agent.%ld",
208 auth_sock_dir, (long) getpid());
210 /* Create the socket. */
211 sock = socket(AF_UNIX, SOCK_STREAM, 0);
213 error("socket: %.100s", strerror(errno));
218 /* Bind it to the name. */
219 memset(&sunaddr, 0, sizeof(sunaddr));
220 sunaddr.sun_family = AF_UNIX;
221 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
223 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
224 error("bind: %.100s", strerror(errno));
229 /* Restore the privileged uid. */
232 /* Start listening on the socket. */
233 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
234 error("listen: %.100s", strerror(errno));
238 /* Allocate a channel for the authentication agent socket. */
239 nc = channel_new("auth socket",
240 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
241 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
242 0, "auth socket", 1);
243 nc->path = xstrdup(auth_sock_name);
247 if (auth_sock_name != NULL)
248 xfree(auth_sock_name);
249 if (auth_sock_dir != NULL) {
250 rmdir(auth_sock_dir);
251 xfree(auth_sock_dir);
255 auth_sock_name = NULL;
256 auth_sock_dir = NULL;
261 display_loginmsg(void)
263 if (buffer_len(&loginmsg) > 0) {
264 buffer_append(&loginmsg, "\0", 1);
265 printf("%s", (char *)buffer_ptr(&loginmsg));
266 buffer_clear(&loginmsg);
271 do_authenticated(Authctxt *authctxt)
273 setproctitle("%s", authctxt->pw->pw_name);
275 /* setup the channel layer */
276 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
277 channel_permit_all_opens();
282 do_authenticated2(authctxt);
284 do_authenticated1(authctxt);
286 do_cleanup(authctxt);
290 * Prepares for an interactive session. This is called after the user has
291 * been successfully authenticated. During this message exchange, pseudo
292 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
293 * are requested, etc.
296 do_authenticated1(Authctxt *authctxt)
300 int success, type, screen_flag;
301 int enable_compression_after_reply = 0;
302 u_int proto_len, data_len, dlen, compression_level = 0;
306 error("no more sessions");
309 s->authctxt = authctxt;
310 s->pw = authctxt->pw;
313 * We stay in this loop until the client requests to execute a shell
319 /* Get a packet from the client. */
320 type = packet_read();
322 /* Process the packet. */
324 case SSH_CMSG_REQUEST_COMPRESSION:
325 compression_level = packet_get_int();
327 if (compression_level < 1 || compression_level > 9) {
328 packet_send_debug("Received invalid compression level %d.",
332 if (options.compression == COMP_NONE) {
333 debug2("compression disabled");
336 /* Enable compression after we have responded with SUCCESS. */
337 enable_compression_after_reply = 1;
341 case SSH_CMSG_REQUEST_PTY:
342 success = session_pty_req(s);
345 case SSH_CMSG_X11_REQUEST_FORWARDING:
346 s->auth_proto = packet_get_string(&proto_len);
347 s->auth_data = packet_get_string(&data_len);
349 screen_flag = packet_get_protocol_flags() &
350 SSH_PROTOFLAG_SCREEN_NUMBER;
351 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
353 if (packet_remaining() == 4) {
355 debug2("Buggy client: "
356 "X11 screen flag missing");
357 s->screen = packet_get_int();
362 success = session_setup_x11fwd(s);
364 xfree(s->auth_proto);
366 s->auth_proto = NULL;
371 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
372 if (!options.allow_agent_forwarding ||
373 no_agent_forwarding_flag || compat13) {
374 debug("Authentication agent forwarding not permitted for this authentication.");
377 debug("Received authentication agent forwarding request.");
378 success = auth_input_request_forwarding(s->pw);
381 case SSH_CMSG_PORT_FORWARD_REQUEST:
382 if (no_port_forwarding_flag) {
383 debug("Port forwarding not permitted for this authentication.");
386 if (!options.allow_tcp_forwarding) {
387 debug("Port forwarding not permitted.");
390 debug("Received TCP/IP port forwarding request.");
391 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
392 options.gateway_ports) < 0) {
393 debug("Port forwarding failed.");
399 case SSH_CMSG_MAX_PACKET_SIZE:
400 if (packet_set_maxsize(packet_get_int()) > 0)
404 case SSH_CMSG_EXEC_SHELL:
405 case SSH_CMSG_EXEC_CMD:
406 if (type == SSH_CMSG_EXEC_CMD) {
407 command = packet_get_string(&dlen);
408 debug("Exec command '%.500s'", command);
409 if (do_exec(s, command) != 0)
411 "command execution failed");
414 if (do_exec(s, NULL) != 0)
416 "shell execution failed");
424 * Any unknown messages in this phase are ignored,
425 * and a failure message is returned.
427 logit("Unknown packet type received after authentication: %d", type);
429 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
433 /* Enable compression now that we have replied if appropriate. */
434 if (enable_compression_after_reply) {
435 enable_compression_after_reply = 0;
436 packet_start_compression(compression_level);
443 * This is called to fork and execute a command when we have no tty. This
444 * will call do_child from the child, and server_loop from the parent after
445 * setting up file descriptors and such.
448 do_exec_no_pty(Session *s, const char *command)
453 int pin[2], pout[2], perr[2];
456 fatal("do_exec_no_pty: no session");
458 /* Allocate pipes for communicating with the program. */
460 error("%s: pipe in: %.100s", __func__, strerror(errno));
463 if (pipe(pout) < 0) {
464 error("%s: pipe out: %.100s", __func__, strerror(errno));
469 if (pipe(perr) < 0) {
470 error("%s: pipe err: %.100s", __func__,
479 int inout[2], err[2];
482 fatal("do_exec_no_pty: no session");
484 /* Uses socket pairs to communicate with the program. */
485 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
486 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
489 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
490 error("%s: socketpair #2: %.100s", __func__,
498 session_proctitle(s);
500 /* Fork the child. */
501 switch ((pid = fork())) {
503 error("%s: fork: %.100s", __func__, strerror(errno));
521 /* Child. Reinitialize the log since the pid has changed. */
522 log_init(__progname, options.log_level,
523 options.log_facility, log_stderr);
526 * Create a new session and process group since the 4.4BSD
527 * setlogin() affects the entire process group.
530 error("setsid failed: %.100s", strerror(errno));
534 * Redirect stdin. We close the parent side of the socket
535 * pair, and make the child side the standard input.
538 if (dup2(pin[0], 0) < 0)
539 perror("dup2 stdin");
542 /* Redirect stdout. */
544 if (dup2(pout[1], 1) < 0)
545 perror("dup2 stdout");
548 /* Redirect stderr. */
550 if (dup2(perr[1], 2) < 0)
551 perror("dup2 stderr");
555 * Redirect stdin, stdout, and stderr. Stdin and stdout will
556 * use the same socket, as some programs (particularly rdist)
557 * seem to depend on it.
561 if (dup2(inout[0], 0) < 0) /* stdin */
562 perror("dup2 stdin");
563 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
564 perror("dup2 stdout");
566 if (dup2(err[0], 2) < 0) /* stderr */
567 perror("dup2 stderr");
573 cray_init_job(s->pw); /* set up cray jid and tmpdir */
576 /* Do processing for the child (exec command etc). */
577 do_child(s, command);
584 signal(WJSIGNAL, cray_job_termination_handler);
587 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
591 /* Set interactive/non-interactive mode. */
592 packet_set_interactive(s->display != NULL,
593 options.ip_qos_interactive, options.ip_qos_bulk);
596 * Clear loginmsg, since it's the child's responsibility to display
597 * it to the user, otherwise multiple sessions may accumulate
598 * multiple copies of the login messages.
600 buffer_clear(&loginmsg);
603 /* We are the parent. Close the child sides of the pipes. */
609 session_set_fds(s, pin[1], pout[0], perr[0],
612 /* Enter the interactive session. */
613 server_loop(pid, pin[1], pout[0], perr[0]);
614 /* server_loop has closed pin[1], pout[0], and perr[0]. */
617 /* We are the parent. Close the child sides of the socket pairs. */
622 * Enter the interactive session. Note: server_loop must be able to
623 * handle the case that fdin and fdout are the same.
626 session_set_fds(s, inout[1], inout[1], err[1],
629 server_loop(pid, inout[1], inout[1], err[1]);
630 /* server_loop has closed inout[1] and err[1]. */
637 * This is called to fork and execute a command when we have a tty. This
638 * will call do_child from the child, and server_loop from the parent after
639 * setting up file descriptors, controlling tty, updating wtmp, utmp,
640 * lastlog, and other such operations.
643 do_exec_pty(Session *s, const char *command)
645 int fdout, ptyfd, ttyfd, ptymaster;
649 fatal("do_exec_pty: no session");
654 * Create another descriptor of the pty master side for use as the
655 * standard input. We could use the original descriptor, but this
656 * simplifies code in server_loop. The descriptor is bidirectional.
657 * Do this before forking (and cleanup in the child) so as to
658 * detect and gracefully fail out-of-fd conditions.
660 if ((fdout = dup(ptyfd)) < 0) {
661 error("%s: dup #1: %s", __func__, strerror(errno));
666 /* we keep a reference to the pty master */
667 if ((ptymaster = dup(ptyfd)) < 0) {
668 error("%s: dup #2: %s", __func__, strerror(errno));
675 /* Fork the child. */
676 switch ((pid = fork())) {
678 error("%s: fork: %.100s", __func__, strerror(errno));
690 /* Child. Reinitialize the log because the pid has changed. */
691 log_init(__progname, options.log_level,
692 options.log_facility, log_stderr);
693 /* Close the master side of the pseudo tty. */
696 /* Make the pseudo tty our controlling tty. */
697 pty_make_controlling_tty(&ttyfd, s->tty);
699 /* Redirect stdin/stdout/stderr from the pseudo tty. */
700 if (dup2(ttyfd, 0) < 0)
701 error("dup2 stdin: %s", strerror(errno));
702 if (dup2(ttyfd, 1) < 0)
703 error("dup2 stdout: %s", strerror(errno));
704 if (dup2(ttyfd, 2) < 0)
705 error("dup2 stderr: %s", strerror(errno));
707 /* Close the extra descriptor for the pseudo tty. */
710 /* record login, etc. similar to login(1) */
712 if (!(options.use_login && command == NULL)) {
714 cray_init_job(s->pw); /* set up cray jid and tmpdir */
716 do_login(s, command);
718 # ifdef LOGIN_NEEDS_UTMPX
724 * Do common processing for the child, such as execing
727 do_child(s, command);
734 signal(WJSIGNAL, cray_job_termination_handler);
737 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
742 /* Parent. Close the slave side of the pseudo tty. */
745 /* Enter interactive session. */
746 s->ptymaster = ptymaster;
747 packet_set_interactive(1,
748 options.ip_qos_interactive, options.ip_qos_bulk);
750 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
752 server_loop(pid, ptyfd, fdout, -1);
753 /* server_loop _has_ closed ptyfd and fdout. */
758 #ifdef LOGIN_NEEDS_UTMPX
760 do_pre_login(Session *s)
763 struct sockaddr_storage from;
764 pid_t pid = getpid();
767 * Get IP address of client. If the connection is not a socket, let
768 * the address be 0.0.0.0.
770 memset(&from, 0, sizeof(from));
771 fromlen = sizeof(from);
772 if (packet_connection_is_on_socket()) {
773 if (getpeername(packet_get_connection_in(),
774 (struct sockaddr *)&from, &fromlen) < 0) {
775 debug("getpeername: %.100s", strerror(errno));
780 record_utmp_only(pid, s->tty, s->pw->pw_name,
781 get_remote_name_or_ip(utmp_len, options.use_dns),
782 (struct sockaddr *)&from, fromlen);
787 * This is called to fork and execute a command. If another command is
788 * to be forced, execute that instead.
791 do_exec(Session *s, const char *command)
795 if (options.adm_forced_command) {
796 original_command = command;
797 command = options.adm_forced_command;
798 if (IS_INTERNAL_SFTP(command)) {
799 s->is_subsystem = s->is_subsystem ?
800 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
801 } else if (s->is_subsystem)
802 s->is_subsystem = SUBSYSTEM_EXT;
803 debug("Forced command (config) '%.900s'", command);
804 } else if (forced_command) {
805 original_command = command;
806 command = forced_command;
807 if (IS_INTERNAL_SFTP(command)) {
808 s->is_subsystem = s->is_subsystem ?
809 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
810 } else if (s->is_subsystem)
811 s->is_subsystem = SUBSYSTEM_EXT;
812 debug("Forced command (key option) '%.900s'", command);
815 #ifdef SSH_AUDIT_EVENTS
817 PRIVSEP(audit_run_command(command));
818 else if (s->ttyfd == -1) {
819 char *shell = s->pw->pw_shell;
821 if (shell[0] == '\0') /* empty shell means /bin/sh */
823 PRIVSEP(audit_run_command(shell));
827 ret = do_exec_pty(s, command);
829 ret = do_exec_no_pty(s, command);
831 original_command = NULL;
834 * Clear loginmsg: it's the child's responsibility to display
835 * it to the user, otherwise multiple sessions may accumulate
836 * multiple copies of the login messages.
838 buffer_clear(&loginmsg);
843 /* administrative, login(1)-like work */
845 do_login(Session *s, const char *command)
848 struct sockaddr_storage from;
849 struct passwd * pw = s->pw;
850 pid_t pid = getpid();
853 * Get IP address of client. If the connection is not a socket, let
854 * the address be 0.0.0.0.
856 memset(&from, 0, sizeof(from));
857 fromlen = sizeof(from);
858 if (packet_connection_is_on_socket()) {
859 if (getpeername(packet_get_connection_in(),
860 (struct sockaddr *)&from, &fromlen) < 0) {
861 debug("getpeername: %.100s", strerror(errno));
866 /* Record that there was a login on that tty from the remote host. */
868 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
869 get_remote_name_or_ip(utmp_len,
871 (struct sockaddr *)&from, fromlen);
875 * If password change is needed, do it now.
876 * This needs to occur before the ~/.hushlogin check.
878 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
881 s->authctxt->force_pwchange = 0;
882 /* XXX - signal [net] parent to enable forwardings */
886 if (check_quietlogin(s, command))
895 * Display the message of the day.
903 if (options.print_motd) {
904 #ifdef HAVE_LOGIN_CAP
905 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
908 f = fopen("/etc/motd", "r");
911 while (fgets(buf, sizeof(buf), f))
920 * Check for quiet login, either .hushlogin or command given.
923 check_quietlogin(Session *s, const char *command)
926 struct passwd *pw = s->pw;
929 /* Return 1 if .hushlogin exists or a command given. */
932 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
933 #ifdef HAVE_LOGIN_CAP
934 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
937 if (stat(buf, &st) >= 0)
944 * Sets the value of the given variable in the environment. If the variable
945 * already exists, its value is overridden.
948 child_set_env(char ***envp, u_int *envsizep, const char *name,
956 * If we're passed an uninitialized list, allocate a single null
957 * entry before continuing.
959 if (*envp == NULL && *envsizep == 0) {
960 *envp = xmalloc(sizeof(char *));
966 * Find the slot where the value should be stored. If the variable
967 * already exists, we reuse the slot; otherwise we append a new slot
968 * at the end of the array, expanding if necessary.
971 namelen = strlen(name);
972 for (i = 0; env[i]; i++)
973 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
976 /* Reuse the slot. */
979 /* New variable. Expand if necessary. */
981 if (i >= envsize - 1) {
983 fatal("child_set_env: too many env vars");
985 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
988 /* Need to set the NULL pointer at end of array beyond the new slot. */
992 /* Allocate space and format the variable in the appropriate slot. */
993 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
994 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
998 * Reads environment variables from the given file and adds/overrides them
999 * into the environment. If the file does not exist, this does nothing.
1000 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1001 * and assignments of the form name=value. No other forms are allowed.
1004 read_environment_file(char ***env, u_int *envsize,
1005 const char *filename)
1012 f = fopen(filename, "r");
1016 while (fgets(buf, sizeof(buf), f)) {
1017 if (++lineno > 1000)
1018 fatal("Too many lines in environment file %s", filename);
1019 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1021 if (!*cp || *cp == '#' || *cp == '\n')
1024 cp[strcspn(cp, "\n")] = '\0';
1026 value = strchr(cp, '=');
1027 if (value == NULL) {
1028 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1033 * Replace the equals sign by nul, and advance value to
1038 child_set_env(env, envsize, cp, value);
1043 #ifdef HAVE_ETC_DEFAULT_LOGIN
1045 * Return named variable from specified environment, or NULL if not present.
1048 child_get_env(char **env, const char *name)
1054 for (i=0; env[i] != NULL; i++)
1055 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1056 return(env[i] + len + 1);
1061 * Read /etc/default/login.
1062 * We pick up the PATH (or SUPATH for root) and UMASK.
1065 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1067 char **tmpenv = NULL, *var;
1068 u_int i, tmpenvsize = 0;
1072 * We don't want to copy the whole file to the child's environment,
1073 * so we use a temporary environment and copy the variables we're
1076 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1082 var = child_get_env(tmpenv, "SUPATH");
1084 var = child_get_env(tmpenv, "PATH");
1086 child_set_env(env, envsize, "PATH", var);
1088 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1089 if (sscanf(var, "%5lo", &mask) == 1)
1090 umask((mode_t)mask);
1092 for (i = 0; tmpenv[i] != NULL; i++)
1096 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1099 copy_environment(char **source, char ***env, u_int *envsize)
1101 char *var_name, *var_val;
1107 for(i = 0; source[i] != NULL; i++) {
1108 var_name = xstrdup(source[i]);
1109 if ((var_val = strstr(var_name, "=")) == NULL) {
1115 debug3("Copy environment: %s=%s", var_name, var_val);
1116 child_set_env(env, envsize, var_name, var_val);
1123 do_setup_env(Session *s, const char *shell)
1128 struct passwd *pw = s->pw;
1129 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1133 /* Initialize the environment. */
1135 env = xcalloc(envsize, sizeof(char *));
1140 * The Windows environment contains some setting which are
1141 * important for a running system. They must not be dropped.
1146 p = fetch_windows_environment();
1147 copy_environment(p, &env, &envsize);
1148 free_windows_environment(p);
1153 /* Allow any GSSAPI methods that we've used to alter
1154 * the childs environment as they see fit
1156 ssh_gssapi_do_child(&env, &envsize);
1159 if (!options.use_login) {
1160 /* Set basic environment. */
1161 for (i = 0; i < s->num_env; i++)
1162 child_set_env(&env, &envsize, s->env[i].name,
1165 child_set_env(&env, &envsize, "USER", pw->pw_name);
1166 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1168 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1170 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1171 #ifdef HAVE_LOGIN_CAP
1172 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1173 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1175 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1176 #else /* HAVE_LOGIN_CAP */
1177 # ifndef HAVE_CYGWIN
1179 * There's no standard path on Windows. The path contains
1180 * important components pointing to the system directories,
1181 * needed for loading shared libraries. So the path better
1182 * remains intact here.
1184 # ifdef HAVE_ETC_DEFAULT_LOGIN
1185 read_etc_default_login(&env, &envsize, pw->pw_uid);
1186 path = child_get_env(env, "PATH");
1187 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1188 if (path == NULL || *path == '\0') {
1189 child_set_env(&env, &envsize, "PATH",
1190 s->pw->pw_uid == 0 ?
1191 SUPERUSER_PATH : _PATH_STDPATH);
1193 # endif /* HAVE_CYGWIN */
1194 #endif /* HAVE_LOGIN_CAP */
1196 snprintf(buf, sizeof buf, "%.200s/%.50s",
1197 _PATH_MAILDIR, pw->pw_name);
1198 child_set_env(&env, &envsize, "MAIL", buf);
1200 /* Normal systems set SHELL by default. */
1201 child_set_env(&env, &envsize, "SHELL", shell);
1204 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1206 /* Set custom environment options from RSA authentication. */
1207 if (!options.use_login) {
1208 while (custom_environment) {
1209 struct envstring *ce = custom_environment;
1212 for (i = 0; str[i] != '=' && str[i]; i++)
1214 if (str[i] == '=') {
1216 child_set_env(&env, &envsize, str, str + i + 1);
1218 custom_environment = ce->next;
1224 /* SSH_CLIENT deprecated */
1225 snprintf(buf, sizeof buf, "%.50s %d %d",
1226 get_remote_ipaddr(), get_remote_port(), get_local_port());
1227 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1229 laddr = get_local_ipaddr(packet_get_connection_in());
1230 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1231 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1233 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1236 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1238 child_set_env(&env, &envsize, "TERM", s->term);
1240 child_set_env(&env, &envsize, "DISPLAY", s->display);
1241 if (original_command)
1242 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1246 if (cray_tmpdir[0] != '\0')
1247 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1248 #endif /* _UNICOS */
1251 * Since we clear KRB5CCNAME at startup, if it's set now then it
1252 * must have been set by a native authentication method (eg AIX or
1253 * SIA), so copy it to the child.
1258 if ((cp = getenv("KRB5CCNAME")) != NULL)
1259 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1266 if ((cp = getenv("AUTHSTATE")) != NULL)
1267 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1268 read_environment_file(&env, &envsize, "/etc/environment");
1272 if (s->authctxt->krb5_ccname)
1273 child_set_env(&env, &envsize, "KRB5CCNAME",
1274 s->authctxt->krb5_ccname);
1278 * Pull in any environment variables that may have
1281 if (options.use_pam) {
1284 p = fetch_pam_child_environment();
1285 copy_environment(p, &env, &envsize);
1286 free_pam_environment(p);
1288 p = fetch_pam_environment();
1289 copy_environment(p, &env, &envsize);
1290 free_pam_environment(p);
1292 #endif /* USE_PAM */
1294 if (auth_sock_name != NULL)
1295 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1298 /* read $HOME/.ssh/environment. */
1299 if (options.permit_user_env && !options.use_login) {
1300 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1301 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1302 read_environment_file(&env, &envsize, buf);
1305 /* dump the environment */
1306 fprintf(stderr, "Environment:\n");
1307 for (i = 0; env[i]; i++)
1308 fprintf(stderr, " %.200s\n", env[i]);
1314 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1315 * first in this order).
1318 do_rc_files(Session *s, const char *shell)
1326 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1328 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1329 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1330 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1331 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1332 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1334 fprintf(stderr, "Running %s\n", cmd);
1335 f = popen(cmd, "w");
1338 fprintf(f, "%s %s\n", s->auth_proto,
1342 fprintf(stderr, "Could not run %s\n",
1344 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1346 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1347 _PATH_SSH_SYSTEM_RC);
1348 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1351 fprintf(f, "%s %s\n", s->auth_proto,
1355 fprintf(stderr, "Could not run %s\n",
1356 _PATH_SSH_SYSTEM_RC);
1357 } else if (do_xauth && options.xauth_location != NULL) {
1358 /* Add authority data to .Xauthority if appropriate. */
1361 "Running %.500s remove %.100s\n",
1362 options.xauth_location, s->auth_display);
1364 "%.500s add %.100s %.100s %.100s\n",
1365 options.xauth_location, s->auth_display,
1366 s->auth_proto, s->auth_data);
1368 snprintf(cmd, sizeof cmd, "%s -q -",
1369 options.xauth_location);
1370 f = popen(cmd, "w");
1372 fprintf(f, "remove %s\n",
1374 fprintf(f, "add %s %s %s\n",
1375 s->auth_display, s->auth_proto,
1379 fprintf(stderr, "Could not run %s\n",
1386 do_nologin(struct passwd *pw)
1389 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1392 #ifdef HAVE_LOGIN_CAP
1393 if (login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid)
1395 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1397 if (pw->pw_uid == 0)
1401 if (stat(nl, &sb) == -1) {
1407 /* /etc/nologin exists. Print its contents if we can and exit. */
1408 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1409 if ((f = fopen(nl, "r")) != NULL) {
1410 while (fgets(buf, sizeof(buf), f))
1418 * Chroot into a directory after checking it for safety: all path components
1419 * must be root-owned directories with strict permissions.
1422 safely_chroot(const char *path, uid_t uid)
1425 char component[MAXPATHLEN];
1429 fatal("chroot path does not begin at root");
1430 if (strlen(path) >= sizeof(component))
1431 fatal("chroot path too long");
1434 * Descend the path, checking that each component is a
1435 * root-owned directory with strict permissions.
1437 for (cp = path; cp != NULL;) {
1438 if ((cp = strchr(cp, '/')) == NULL)
1439 strlcpy(component, path, sizeof(component));
1442 memcpy(component, path, cp - path);
1443 component[cp - path] = '\0';
1446 debug3("%s: checking '%s'", __func__, component);
1448 if (stat(component, &st) != 0)
1449 fatal("%s: stat(\"%s\"): %s", __func__,
1450 component, strerror(errno));
1451 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1452 fatal("bad ownership or modes for chroot "
1453 "directory %s\"%s\"",
1454 cp == NULL ? "" : "component ", component);
1455 if (!S_ISDIR(st.st_mode))
1456 fatal("chroot path %s\"%s\" is not a directory",
1457 cp == NULL ? "" : "component ", component);
1461 if (chdir(path) == -1)
1462 fatal("Unable to chdir to chroot path \"%s\": "
1463 "%s", path, strerror(errno));
1464 if (chroot(path) == -1)
1465 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1466 if (chdir("/") == -1)
1467 fatal("%s: chdir(/) after chroot: %s",
1468 __func__, strerror(errno));
1469 verbose("Changed root directory to \"%s\"", path);
1472 /* Set login name, uid, gid, and groups. */
1474 do_setusercontext(struct passwd *pw)
1476 char *chroot_path, *tmp;
1478 platform_setusercontext(pw);
1480 if (platform_privileged_uidswap()) {
1481 #ifdef HAVE_LOGIN_CAP
1482 if (setusercontext(lc, pw, pw->pw_uid,
1483 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1484 perror("unable to set user context");
1488 if (setlogin(pw->pw_name) < 0)
1489 error("setlogin failed: %s", strerror(errno));
1490 if (setgid(pw->pw_gid) < 0) {
1494 /* Initialize the group list. */
1495 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1496 perror("initgroups");
1502 platform_setusercontext_post_groups(pw);
1504 if (options.chroot_directory != NULL &&
1505 strcasecmp(options.chroot_directory, "none") != 0) {
1506 tmp = tilde_expand_filename(options.chroot_directory,
1508 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1509 "u", pw->pw_name, (char *)NULL);
1510 safely_chroot(chroot_path, pw->pw_uid);
1515 #ifdef HAVE_LOGIN_CAP
1516 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1517 perror("unable to set user context (setuser)");
1521 /* Permanently switch to the desired uid. */
1522 permanently_set_uid(pw);
1526 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1527 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1531 do_pwchange(Session *s)
1534 fprintf(stderr, "WARNING: Your password has expired.\n");
1535 if (s->ttyfd != -1) {
1537 "You must change your password now and login again!\n");
1541 #ifdef PASSWD_NEEDS_USERNAME
1542 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1545 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1550 "Password change required but no TTY available.\n");
1556 launch_login(struct passwd *pw, const char *hostname)
1558 /* Launch login(1). */
1560 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1561 #ifdef xxxLOGIN_NEEDS_TERM
1562 (s->term ? s->term : "unknown"),
1563 #endif /* LOGIN_NEEDS_TERM */
1564 #ifdef LOGIN_NO_ENDOPT
1565 "-p", "-f", pw->pw_name, (char *)NULL);
1567 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1570 /* Login couldn't be executed, die. */
1577 child_close_fds(void)
1579 if (packet_get_connection_in() == packet_get_connection_out())
1580 close(packet_get_connection_in());
1582 close(packet_get_connection_in());
1583 close(packet_get_connection_out());
1586 * Close all descriptors related to channels. They will still remain
1587 * open in the parent.
1589 /* XXX better use close-on-exec? -markus */
1590 channel_close_all();
1593 * Close any extra file descriptors. Note that there may still be
1594 * descriptors left by system functions. They will be closed later.
1599 * Close any extra open file descriptors so that we don't have them
1600 * hanging around in clients. Note that we want to do this after
1601 * initgroups, because at least on Solaris 2.3 it leaves file
1604 closefrom(STDERR_FILENO + 1);
1608 * Performs common processing for the child, such as setting up the
1609 * environment, closing extra file descriptors, setting the user and group
1610 * ids, and executing the command or shell.
1614 do_child(Session *s, const char *command)
1616 extern char **environ;
1618 char *argv[ARGV_MAX];
1619 const char *shell, *shell0, *hostname = NULL;
1620 struct passwd *pw = s->pw;
1623 /* remove hostkey from the child's memory */
1624 destroy_sensitive_data();
1626 /* Force a password change */
1627 if (s->authctxt->force_pwchange) {
1628 do_setusercontext(pw);
1634 /* login(1) is only called if we execute the login shell */
1635 if (options.use_login && command != NULL)
1636 options.use_login = 0;
1639 cray_setup(pw->pw_uid, pw->pw_name, command);
1640 #endif /* _UNICOS */
1643 * Login(1) does this as well, and it needs uid 0 for the "-h"
1644 * switch, so we let login(1) to this for us.
1646 if (!options.use_login) {
1648 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1649 if (!check_quietlogin(s, command))
1651 #else /* HAVE_OSF_SIA */
1652 /* When PAM is enabled we rely on it to do the nologin check */
1653 if (!options.use_pam)
1655 do_setusercontext(pw);
1657 * PAM session modules in do_setusercontext may have
1658 * generated messages, so if this in an interactive
1659 * login then display them too.
1661 if (!check_quietlogin(s, command))
1663 #endif /* HAVE_OSF_SIA */
1667 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1668 debug3("PAM session not opened, exiting");
1675 * Get the shell from the password data. An empty shell field is
1676 * legal, and means /bin/sh.
1678 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1681 * Make sure $SHELL points to the shell from the password file,
1682 * even if shell is overridden from login.conf
1684 env = do_setup_env(s, shell);
1686 #ifdef HAVE_LOGIN_CAP
1687 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1690 /* we have to stash the hostname before we close our socket. */
1691 if (options.use_login)
1692 hostname = get_remote_name_or_ip(utmp_len,
1695 * Close the connection descriptors; note that this is the child, and
1696 * the server will still have the socket open, and it is important
1697 * that we do not shutdown it. Note that the descriptors cannot be
1698 * closed before building the environment, as we call
1699 * get_remote_ipaddr there.
1704 * Must take new environment into use so that .ssh/rc,
1705 * /etc/ssh/sshrc and xauth are run in the proper environment.
1709 #if defined(KRB5) && defined(USE_AFS)
1711 * At this point, we check to see if AFS is active and if we have
1712 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1713 * if we can (and need to) extend the ticket into an AFS token. If
1714 * we don't do this, we run into potential problems if the user's
1715 * home directory is in AFS and it's not world-readable.
1718 if (options.kerberos_get_afs_token && k_hasafs() &&
1719 (s->authctxt->krb5_ctx != NULL)) {
1722 debug("Getting AFS token");
1726 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1727 krb5_afslog(s->authctxt->krb5_ctx,
1728 s->authctxt->krb5_fwd_ccache, cell, NULL);
1730 krb5_afslog_home(s->authctxt->krb5_ctx,
1731 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1735 /* Change current directory to the user's home directory. */
1736 if (chdir(pw->pw_dir) < 0) {
1737 /* Suppress missing homedir warning for chroot case */
1738 #ifdef HAVE_LOGIN_CAP
1739 r = login_getcapbool(lc, "requirehome", 0);
1741 if (r || options.chroot_directory == NULL ||
1742 strcasecmp(options.chroot_directory, "none") == 0)
1743 fprintf(stderr, "Could not chdir to home "
1744 "directory %s: %s\n", pw->pw_dir,
1750 closefrom(STDERR_FILENO + 1);
1752 if (!options.use_login)
1753 do_rc_files(s, shell);
1755 /* restore SIGPIPE for child */
1756 signal(SIGPIPE, SIG_DFL);
1758 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1759 printf("This service allows sftp connections only.\n");
1762 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1763 extern int optind, optreset;
1767 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1768 args = xstrdup(command ? command : "sftp-server");
1769 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1770 if (i < ARGV_MAX - 1)
1773 optind = optreset = 1;
1774 __progname = argv[0];
1776 ssh_selinux_change_context("sftpd_t");
1778 exit(sftp_server_main(i, argv, s->pw));
1783 if (options.use_login) {
1784 launch_login(pw, hostname);
1788 /* Get the last component of the shell name. */
1789 if ((shell0 = strrchr(shell, '/')) != NULL)
1795 * If we have no command, execute the shell. In this case, the shell
1796 * name to be passed in argv[0] is preceded by '-' to indicate that
1797 * this is a login shell.
1802 /* Start the shell. Set initial character to '-'. */
1805 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1806 >= sizeof(argv0) - 1) {
1812 /* Execute the shell. */
1815 execve(shell, argv, env);
1817 /* Executing the shell failed. */
1822 * Execute the command using the user's shell. This uses the -c
1823 * option to execute the command.
1825 argv[0] = (char *) shell0;
1827 argv[2] = (char *) command;
1829 execve(shell, argv, env);
1835 session_unused(int id)
1837 debug3("%s: session id %d unused", __func__, id);
1838 if (id >= options.max_sessions ||
1839 id >= sessions_nalloc) {
1840 fatal("%s: insane session id %d (max %d nalloc %d)",
1841 __func__, id, options.max_sessions, sessions_nalloc);
1843 bzero(&sessions[id], sizeof(*sessions));
1844 sessions[id].self = id;
1845 sessions[id].used = 0;
1846 sessions[id].chanid = -1;
1847 sessions[id].ptyfd = -1;
1848 sessions[id].ttyfd = -1;
1849 sessions[id].ptymaster = -1;
1850 sessions[id].x11_chanids = NULL;
1851 sessions[id].next_unused = sessions_first_unused;
1852 sessions_first_unused = id;
1860 if (sessions_first_unused == -1) {
1861 if (sessions_nalloc >= options.max_sessions)
1863 debug2("%s: allocate (allocated %d max %d)",
1864 __func__, sessions_nalloc, options.max_sessions);
1865 tmp = xrealloc(sessions, sessions_nalloc + 1,
1868 error("%s: cannot allocate %d sessions",
1869 __func__, sessions_nalloc + 1);
1873 session_unused(sessions_nalloc++);
1876 if (sessions_first_unused >= sessions_nalloc ||
1877 sessions_first_unused < 0) {
1878 fatal("%s: insane first_unused %d max %d nalloc %d",
1879 __func__, sessions_first_unused, options.max_sessions,
1883 s = &sessions[sessions_first_unused];
1885 fatal("%s: session %d already used",
1886 __func__, sessions_first_unused);
1888 sessions_first_unused = s->next_unused;
1890 s->next_unused = -1;
1891 debug("session_new: session %d", s->self);
1900 for (i = 0; i < sessions_nalloc; i++) {
1901 Session *s = &sessions[i];
1903 debug("dump: used %d next_unused %d session %d %p "
1904 "channel %d pid %ld",
1915 session_open(Authctxt *authctxt, int chanid)
1917 Session *s = session_new();
1918 debug("session_open: channel %d", chanid);
1920 error("no more sessions");
1923 s->authctxt = authctxt;
1924 s->pw = authctxt->pw;
1925 if (s->pw == NULL || !authctxt->valid)
1926 fatal("no user for session %d", s->self);
1927 debug("session_open: session %d: link with channel %d", s->self, chanid);
1933 session_by_tty(char *tty)
1936 for (i = 0; i < sessions_nalloc; i++) {
1937 Session *s = &sessions[i];
1938 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1939 debug("session_by_tty: session %d tty %s", i, tty);
1943 debug("session_by_tty: unknown tty %.100s", tty);
1949 session_by_channel(int id)
1952 for (i = 0; i < sessions_nalloc; i++) {
1953 Session *s = &sessions[i];
1954 if (s->used && s->chanid == id) {
1955 debug("session_by_channel: session %d channel %d",
1960 debug("session_by_channel: unknown channel %d", id);
1966 session_by_x11_channel(int id)
1970 for (i = 0; i < sessions_nalloc; i++) {
1971 Session *s = &sessions[i];
1973 if (s->x11_chanids == NULL || !s->used)
1975 for (j = 0; s->x11_chanids[j] != -1; j++) {
1976 if (s->x11_chanids[j] == id) {
1977 debug("session_by_x11_channel: session %d "
1978 "channel %d", s->self, id);
1983 debug("session_by_x11_channel: unknown channel %d", id);
1989 session_by_pid(pid_t pid)
1992 debug("session_by_pid: pid %ld", (long)pid);
1993 for (i = 0; i < sessions_nalloc; i++) {
1994 Session *s = &sessions[i];
1995 if (s->used && s->pid == pid)
1998 error("session_by_pid: unknown pid %ld", (long)pid);
2004 session_window_change_req(Session *s)
2006 s->col = packet_get_int();
2007 s->row = packet_get_int();
2008 s->xpixel = packet_get_int();
2009 s->ypixel = packet_get_int();
2011 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2016 session_pty_req(Session *s)
2022 debug("Allocating a pty not permitted for this authentication.");
2025 if (s->ttyfd != -1) {
2026 packet_disconnect("Protocol error: you already have a pty.");
2030 s->term = packet_get_string(&len);
2033 s->col = packet_get_int();
2034 s->row = packet_get_int();
2036 s->row = packet_get_int();
2037 s->col = packet_get_int();
2039 s->xpixel = packet_get_int();
2040 s->ypixel = packet_get_int();
2042 if (strcmp(s->term, "") == 0) {
2047 /* Allocate a pty and open it. */
2048 debug("Allocating pty.");
2049 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2056 error("session_pty_req: session %d alloc failed", s->self);
2059 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2061 /* for SSH1 the tty modes length is not given */
2063 n_bytes = packet_remaining();
2064 tty_parse_modes(s->ttyfd, &n_bytes);
2067 pty_setowner(s->pw, s->tty);
2069 /* Set window size from the packet. */
2070 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2073 session_proctitle(s);
2078 session_subsystem_req(Session *s)
2083 char *prog, *cmd, *subsys = packet_get_string(&len);
2087 logit("subsystem request for %.100s by user %s", subsys,
2090 for (i = 0; i < options.num_subsystems; i++) {
2091 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2092 prog = options.subsystem_command[i];
2093 cmd = options.subsystem_args[i];
2094 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2095 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2096 debug("subsystem: %s", prog);
2098 if (stat(prog, &st) < 0)
2099 debug("subsystem: cannot stat %s: %s",
2100 prog, strerror(errno));
2101 s->is_subsystem = SUBSYSTEM_EXT;
2102 debug("subsystem: exec() %s", cmd);
2104 success = do_exec(s, cmd) == 0;
2110 logit("subsystem request for %.100s failed, subsystem not found",
2118 session_x11_req(Session *s)
2122 if (s->auth_proto != NULL || s->auth_data != NULL) {
2123 error("session_x11_req: session %d: "
2124 "x11 forwarding already active", s->self);
2127 s->single_connection = packet_get_char();
2128 s->auth_proto = packet_get_string(NULL);
2129 s->auth_data = packet_get_string(NULL);
2130 s->screen = packet_get_int();
2133 success = session_setup_x11fwd(s);
2135 xfree(s->auth_proto);
2136 xfree(s->auth_data);
2137 s->auth_proto = NULL;
2138 s->auth_data = NULL;
2144 session_shell_req(Session *s)
2147 return do_exec(s, NULL) == 0;
2151 session_exec_req(Session *s)
2155 char *command = packet_get_string(&len);
2157 success = do_exec(s, command) == 0;
2163 session_break_req(Session *s)
2166 packet_get_int(); /* ignored */
2169 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0)
2175 session_env_req(Session *s)
2178 u_int name_len, val_len, i;
2180 name = packet_get_string(&name_len);
2181 val = packet_get_string(&val_len);
2184 /* Don't set too many environment variables */
2185 if (s->num_env > 128) {
2186 debug2("Ignoring env request %s: too many env vars", name);
2190 for (i = 0; i < options.num_accept_env; i++) {
2191 if (match_pattern(name, options.accept_env[i])) {
2192 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2193 s->env = xrealloc(s->env, s->num_env + 1,
2195 s->env[s->num_env].name = name;
2196 s->env[s->num_env].val = val;
2201 debug2("Ignoring env request %s: disallowed name", name);
2210 session_auth_agent_req(Session *s)
2212 static int called = 0;
2214 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2215 debug("session_auth_agent_req: no_agent_forwarding_flag");
2222 return auth_input_request_forwarding(s->pw);
2227 session_input_channel_req(Channel *c, const char *rtype)
2232 if ((s = session_by_channel(c->self)) == NULL) {
2233 logit("session_input_channel_req: no session %d req %.100s",
2237 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2240 * a session is in LARVAL state until a shell, a command
2241 * or a subsystem is executed
2243 if (c->type == SSH_CHANNEL_LARVAL) {
2244 if (strcmp(rtype, "shell") == 0) {
2245 success = session_shell_req(s);
2246 } else if (strcmp(rtype, "exec") == 0) {
2247 success = session_exec_req(s);
2248 } else if (strcmp(rtype, "pty-req") == 0) {
2249 success = session_pty_req(s);
2250 } else if (strcmp(rtype, "x11-req") == 0) {
2251 success = session_x11_req(s);
2252 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2253 success = session_auth_agent_req(s);
2254 } else if (strcmp(rtype, "subsystem") == 0) {
2255 success = session_subsystem_req(s);
2256 } else if (strcmp(rtype, "env") == 0) {
2257 success = session_env_req(s);
2260 if (strcmp(rtype, "window-change") == 0) {
2261 success = session_window_change_req(s);
2262 } else if (strcmp(rtype, "break") == 0) {
2263 success = session_break_req(s);
2270 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2274 fatal("session_set_fds: called for proto != 2.0");
2276 * now that have a child and a pipe to the child,
2277 * we can activate our channel and register the fd's
2279 if (s->chanid == -1)
2280 fatal("no channel for session %d", s->self);
2281 channel_set_fds(s->chanid,
2283 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2284 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2288 * Function to perform pty cleanup. Also called if we get aborted abnormally
2289 * (e.g., due to a dropped connection).
2292 session_pty_cleanup2(Session *s)
2295 error("session_pty_cleanup: no session");
2301 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2303 /* Record that the user has logged out. */
2305 record_logout(s->pid, s->tty, s->pw->pw_name);
2307 /* Release the pseudo-tty. */
2309 pty_release(s->tty);
2312 * Close the server side of the socket pairs. We must do this after
2313 * the pty cleanup, so that another process doesn't get this pty
2314 * while we're still cleaning up.
2316 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2317 error("close(s->ptymaster/%d): %s",
2318 s->ptymaster, strerror(errno));
2320 /* unlink pty from session */
2325 session_pty_cleanup(Session *s)
2327 PRIVSEP(session_pty_cleanup2(s));
2333 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2348 return "SIG@openssh.com";
2352 session_close_x11(int id)
2356 if ((c = channel_by_id(id)) == NULL) {
2357 debug("session_close_x11: x11 channel %d missing", id);
2359 /* Detach X11 listener */
2360 debug("session_close_x11: detach x11 channel %d", id);
2361 channel_cancel_cleanup(id);
2362 if (c->ostate != CHAN_OUTPUT_CLOSED)
2368 session_close_single_x11(int id, void *arg)
2373 debug3("session_close_single_x11: channel %d", id);
2374 channel_cancel_cleanup(id);
2375 if ((s = session_by_x11_channel(id)) == NULL)
2376 fatal("session_close_single_x11: no x11 channel %d", id);
2377 for (i = 0; s->x11_chanids[i] != -1; i++) {
2378 debug("session_close_single_x11: session %d: "
2379 "closing channel %d", s->self, s->x11_chanids[i]);
2381 * The channel "id" is already closing, but make sure we
2382 * close all of its siblings.
2384 if (s->x11_chanids[i] != id)
2385 session_close_x11(s->x11_chanids[i]);
2387 xfree(s->x11_chanids);
2388 s->x11_chanids = NULL;
2393 if (s->auth_proto) {
2394 xfree(s->auth_proto);
2395 s->auth_proto = NULL;
2398 xfree(s->auth_data);
2399 s->auth_data = NULL;
2401 if (s->auth_display) {
2402 xfree(s->auth_display);
2403 s->auth_display = NULL;
2408 session_exit_message(Session *s, int status)
2412 if ((c = channel_lookup(s->chanid)) == NULL)
2413 fatal("session_exit_message: session %d: no channel %d",
2414 s->self, s->chanid);
2415 debug("session_exit_message: session %d channel %d pid %ld",
2416 s->self, s->chanid, (long)s->pid);
2418 if (WIFEXITED(status)) {
2419 channel_request_start(s->chanid, "exit-status", 0);
2420 packet_put_int(WEXITSTATUS(status));
2422 } else if (WIFSIGNALED(status)) {
2423 channel_request_start(s->chanid, "exit-signal", 0);
2424 packet_put_cstring(sig2name(WTERMSIG(status)));
2426 packet_put_char(WCOREDUMP(status)? 1 : 0);
2427 #else /* WCOREDUMP */
2429 #endif /* WCOREDUMP */
2430 packet_put_cstring("");
2431 packet_put_cstring("");
2434 /* Some weird exit cause. Just exit. */
2435 packet_disconnect("wait returned status %04x.", status);
2438 /* disconnect channel */
2439 debug("session_exit_message: release channel %d", s->chanid);
2442 * Adjust cleanup callback attachment to send close messages when
2443 * the channel gets EOF. The session will be then be closed
2444 * by session_close_by_channel when the childs close their fds.
2446 channel_register_cleanup(c->self, session_close_by_channel, 1);
2449 * emulate a write failure with 'chan_write_failed', nobody will be
2450 * interested in data we write.
2451 * Note that we must not call 'chan_read_failed', since there could
2452 * be some more data waiting in the pipe.
2454 if (c->ostate != CHAN_OUTPUT_CLOSED)
2455 chan_write_failed(c);
2459 session_close(Session *s)
2463 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2465 session_pty_cleanup(s);
2471 xfree(s->x11_chanids);
2472 if (s->auth_display)
2473 xfree(s->auth_display);
2475 xfree(s->auth_data);
2477 xfree(s->auth_proto);
2478 if (s->env != NULL) {
2479 for (i = 0; i < s->num_env; i++) {
2480 xfree(s->env[i].name);
2481 xfree(s->env[i].val);
2485 session_proctitle(s);
2486 session_unused(s->self);
2490 session_close_by_pid(pid_t pid, int status)
2492 Session *s = session_by_pid(pid);
2494 debug("session_close_by_pid: no session for pid %ld",
2498 if (s->chanid != -1)
2499 session_exit_message(s, status);
2501 session_pty_cleanup(s);
2506 * this is called when a channel dies before
2507 * the session 'child' itself dies
2510 session_close_by_channel(int id, void *arg)
2512 Session *s = session_by_channel(id);
2516 debug("session_close_by_channel: no session for id %d", id);
2519 debug("session_close_by_channel: channel %d child %ld",
2522 debug("session_close_by_channel: channel %d: has child", id);
2524 * delay detach of session, but release pty, since
2525 * the fd's to the child are already closed
2528 session_pty_cleanup(s);
2531 /* detach by removing callback */
2532 channel_cancel_cleanup(s->chanid);
2534 /* Close any X11 listeners associated with this session */
2535 if (s->x11_chanids != NULL) {
2536 for (i = 0; s->x11_chanids[i] != -1; i++) {
2537 session_close_x11(s->x11_chanids[i]);
2538 s->x11_chanids[i] = -1;
2547 session_destroy_all(void (*closefunc)(Session *))
2550 for (i = 0; i < sessions_nalloc; i++) {
2551 Session *s = &sessions[i];
2553 if (closefunc != NULL)
2562 session_tty_list(void)
2564 static char buf[1024];
2569 for (i = 0; i < sessions_nalloc; i++) {
2570 Session *s = &sessions[i];
2571 if (s->used && s->ttyfd != -1) {
2573 if (strncmp(s->tty, "/dev/", 5) != 0) {
2574 cp = strrchr(s->tty, '/');
2575 cp = (cp == NULL) ? s->tty : cp + 1;
2580 strlcat(buf, ",", sizeof buf);
2581 strlcat(buf, cp, sizeof buf);
2585 strlcpy(buf, "notty", sizeof buf);
2590 session_proctitle(Session *s)
2593 error("no user for session %d", s->self);
2595 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2599 session_setup_x11fwd(Session *s)
2602 char display[512], auth_display[512];
2603 char hostname[MAXHOSTNAMELEN];
2606 if (no_x11_forwarding_flag) {
2607 packet_send_debug("X11 forwarding disabled in user configuration file.");
2610 if (!options.x11_forwarding) {
2611 debug("X11 forwarding disabled in server configuration file.");
2614 if (!options.xauth_location ||
2615 (stat(options.xauth_location, &st) == -1)) {
2616 packet_send_debug("No xauth program; cannot forward with spoofing.");
2619 if (options.use_login) {
2620 packet_send_debug("X11 forwarding disabled; "
2621 "not compatible with UseLogin=yes.");
2624 if (s->display != NULL) {
2625 debug("X11 display already set.");
2628 if (x11_create_display_inet(options.x11_display_offset,
2629 options.x11_use_localhost, s->single_connection,
2630 &s->display_number, &s->x11_chanids) == -1) {
2631 debug("x11_create_display_inet failed.");
2634 for (i = 0; s->x11_chanids[i] != -1; i++) {
2635 channel_register_cleanup(s->x11_chanids[i],
2636 session_close_single_x11, 0);
2639 /* Set up a suitable value for the DISPLAY variable. */
2640 if (gethostname(hostname, sizeof(hostname)) < 0)
2641 fatal("gethostname: %.100s", strerror(errno));
2643 * auth_display must be used as the displayname when the
2644 * authorization entry is added with xauth(1). This will be
2645 * different than the DISPLAY string for localhost displays.
2647 if (options.x11_use_localhost) {
2648 snprintf(display, sizeof display, "localhost:%u.%u",
2649 s->display_number, s->screen);
2650 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2651 s->display_number, s->screen);
2652 s->display = xstrdup(display);
2653 s->auth_display = xstrdup(auth_display);
2655 #ifdef IPADDR_IN_DISPLAY
2657 struct in_addr my_addr;
2659 he = gethostbyname(hostname);
2661 error("Can't get IP address for X11 DISPLAY.");
2662 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2665 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2666 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2667 s->display_number, s->screen);
2669 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2670 s->display_number, s->screen);
2672 s->display = xstrdup(display);
2673 s->auth_display = xstrdup(display);
2680 do_authenticated2(Authctxt *authctxt)
2682 server_loop2(authctxt);
2686 do_cleanup(Authctxt *authctxt)
2688 static int called = 0;
2690 debug("do_cleanup");
2692 /* no cleanup if we're in the child for login shell */
2696 /* avoid double cleanup */
2701 if (authctxt == NULL)
2705 if (options.use_pam) {
2707 sshpam_thread_cleanup();
2711 if (!authctxt->authenticated)
2715 if (options.kerberos_ticket_cleanup &&
2717 krb5_cleanup_proc(authctxt);
2721 if (compat20 && options.gss_cleanup_creds)
2722 ssh_gssapi_cleanup_creds();
2725 /* remove agent socket */
2726 auth_sock_cleanup_proc(authctxt->pw);
2729 * Cleanup ptys/utmp only if privsep is disabled,
2730 * or if running in monitor.
2732 if (!use_privsep || mm_is_monitor())
2733 session_destroy_all(session_pty_cleanup2);