1 /* $OpenBSD: session.c,v 1.260 2012/03/15 03:10:27 guenther 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.
39 #include <sys/types.h>
40 #include <sys/param.h>
41 #ifdef HAVE_SYS_STAT_H
42 # include <sys/stat.h>
44 #include <sys/socket.h>
48 #include <arpa/inet.h>
64 #include "openbsd-compat/sys-queue.h"
83 #include "auth-options.h"
84 #include "pathnames.h"
88 #include "serverloop.h"
93 #include "monitor_wrap.h"
96 #if defined(KRB5) && defined(USE_AFS)
101 #include <selinux/selinux.h>
104 #define IS_INTERNAL_SFTP(c) \
105 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
106 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
107 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
108 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
112 Session *session_new(void);
113 void session_set_fds(Session *, int, int, int, int, int);
114 void session_pty_cleanup(Session *);
115 void session_proctitle(Session *);
116 int session_setup_x11fwd(Session *);
117 int do_exec_pty(Session *, const char *);
118 int do_exec_no_pty(Session *, const char *);
119 int do_exec(Session *, const char *);
120 void do_login(Session *, const char *);
121 #ifdef LOGIN_NEEDS_UTMPX
122 static void do_pre_login(Session *s);
124 void do_child(Session *, const char *);
126 int check_quietlogin(Session *, const char *);
128 static void do_authenticated1(Authctxt *);
129 static void do_authenticated2(Authctxt *);
131 static int session_pty_req(Session *);
134 extern ServerOptions options;
135 extern char *__progname;
136 extern int log_stderr;
137 extern int debug_flag;
138 extern u_int utmp_len;
139 extern int startup_pipe;
140 extern void destroy_sensitive_data(void);
141 extern Buffer loginmsg;
143 /* original command from peer. */
144 const char *original_command = NULL;
147 static int sessions_first_unused = -1;
148 static int sessions_nalloc = 0;
149 static Session *sessions = NULL;
151 #define SUBSYSTEM_NONE 0
152 #define SUBSYSTEM_EXT 1
153 #define SUBSYSTEM_INT_SFTP 2
154 #define SUBSYSTEM_INT_SFTP_ERROR 3
156 #ifdef HAVE_LOGIN_CAP
160 static int is_child = 0;
162 /* Name and directory of socket for authentication agent forwarding. */
163 static char *auth_sock_name = NULL;
164 static char *auth_sock_dir = NULL;
166 /* removes the agent forwarding socket */
169 auth_sock_cleanup_proc(struct passwd *pw)
171 if (auth_sock_name != NULL) {
172 temporarily_use_uid(pw);
173 unlink(auth_sock_name);
174 rmdir(auth_sock_dir);
175 auth_sock_name = NULL;
181 auth_input_request_forwarding(struct passwd * pw)
185 struct sockaddr_un sunaddr;
187 if (auth_sock_name != NULL) {
188 error("authentication forwarding requested twice.");
192 /* Temporarily drop privileged uid for mkdir/bind. */
193 temporarily_use_uid(pw);
195 /* Allocate a buffer for the socket name, and format the name. */
196 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
198 /* Create private directory for socket */
199 if (mkdtemp(auth_sock_dir) == NULL) {
200 packet_send_debug("Agent forwarding disabled: "
201 "mkdtemp() failed: %.100s", strerror(errno));
203 xfree(auth_sock_dir);
204 auth_sock_dir = NULL;
208 xasprintf(&auth_sock_name, "%s/agent.%ld",
209 auth_sock_dir, (long) getpid());
211 /* Create the socket. */
212 sock = socket(AF_UNIX, SOCK_STREAM, 0);
214 error("socket: %.100s", strerror(errno));
219 /* Bind it to the name. */
220 memset(&sunaddr, 0, sizeof(sunaddr));
221 sunaddr.sun_family = AF_UNIX;
222 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
224 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
225 error("bind: %.100s", strerror(errno));
230 /* Restore the privileged uid. */
233 /* Start listening on the socket. */
234 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
235 error("listen: %.100s", strerror(errno));
239 /* Allocate a channel for the authentication agent socket. */
240 nc = channel_new("auth socket",
241 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
242 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
243 0, "auth socket", 1);
244 nc->path = xstrdup(auth_sock_name);
248 if (auth_sock_name != NULL)
249 xfree(auth_sock_name);
250 if (auth_sock_dir != NULL) {
251 rmdir(auth_sock_dir);
252 xfree(auth_sock_dir);
256 auth_sock_name = NULL;
257 auth_sock_dir = NULL;
262 display_loginmsg(void)
264 if (buffer_len(&loginmsg) > 0) {
265 buffer_append(&loginmsg, "\0", 1);
266 printf("%s", (char *)buffer_ptr(&loginmsg));
267 buffer_clear(&loginmsg);
272 do_authenticated(Authctxt *authctxt)
274 setproctitle("%s", authctxt->pw->pw_name);
276 /* setup the channel layer */
277 if (!no_port_forwarding_flag && options.allow_tcp_forwarding)
278 channel_permit_all_opens();
283 do_authenticated2(authctxt);
285 do_authenticated1(authctxt);
287 do_cleanup(authctxt);
291 * Prepares for an interactive session. This is called after the user has
292 * been successfully authenticated. During this message exchange, pseudo
293 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
294 * are requested, etc.
297 do_authenticated1(Authctxt *authctxt)
301 int success, type, screen_flag;
302 int enable_compression_after_reply = 0;
303 u_int proto_len, data_len, dlen, compression_level = 0;
307 error("no more sessions");
310 s->authctxt = authctxt;
311 s->pw = authctxt->pw;
314 * We stay in this loop until the client requests to execute a shell
320 /* Get a packet from the client. */
321 type = packet_read();
323 /* Process the packet. */
325 case SSH_CMSG_REQUEST_COMPRESSION:
326 compression_level = packet_get_int();
328 if (compression_level < 1 || compression_level > 9) {
329 packet_send_debug("Received invalid compression level %d.",
333 if (options.compression == COMP_NONE) {
334 debug2("compression disabled");
337 /* Enable compression after we have responded with SUCCESS. */
338 enable_compression_after_reply = 1;
342 case SSH_CMSG_REQUEST_PTY:
343 success = session_pty_req(s);
346 case SSH_CMSG_X11_REQUEST_FORWARDING:
347 s->auth_proto = packet_get_string(&proto_len);
348 s->auth_data = packet_get_string(&data_len);
350 screen_flag = packet_get_protocol_flags() &
351 SSH_PROTOFLAG_SCREEN_NUMBER;
352 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
354 if (packet_remaining() == 4) {
356 debug2("Buggy client: "
357 "X11 screen flag missing");
358 s->screen = packet_get_int();
363 success = session_setup_x11fwd(s);
365 xfree(s->auth_proto);
367 s->auth_proto = NULL;
372 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
373 if (!options.allow_agent_forwarding ||
374 no_agent_forwarding_flag || compat13) {
375 debug("Authentication agent forwarding not permitted for this authentication.");
378 debug("Received authentication agent forwarding request.");
379 success = auth_input_request_forwarding(s->pw);
382 case SSH_CMSG_PORT_FORWARD_REQUEST:
383 if (no_port_forwarding_flag) {
384 debug("Port forwarding not permitted for this authentication.");
387 if (!options.allow_tcp_forwarding) {
388 debug("Port forwarding not permitted.");
391 debug("Received TCP/IP port forwarding request.");
392 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
393 options.gateway_ports) < 0) {
394 debug("Port forwarding failed.");
400 case SSH_CMSG_MAX_PACKET_SIZE:
401 if (packet_set_maxsize(packet_get_int()) > 0)
405 case SSH_CMSG_EXEC_SHELL:
406 case SSH_CMSG_EXEC_CMD:
407 if (type == SSH_CMSG_EXEC_CMD) {
408 command = packet_get_string(&dlen);
409 debug("Exec command '%.500s'", command);
410 if (do_exec(s, command) != 0)
412 "command execution failed");
415 if (do_exec(s, NULL) != 0)
417 "shell execution failed");
425 * Any unknown messages in this phase are ignored,
426 * and a failure message is returned.
428 logit("Unknown packet type received after authentication: %d", type);
430 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
434 /* Enable compression now that we have replied if appropriate. */
435 if (enable_compression_after_reply) {
436 enable_compression_after_reply = 0;
437 packet_start_compression(compression_level);
444 * This is called to fork and execute a command when we have no tty. This
445 * will call do_child from the child, and server_loop from the parent after
446 * setting up file descriptors and such.
449 do_exec_no_pty(Session *s, const char *command)
454 int pin[2], pout[2], perr[2];
457 fatal("do_exec_no_pty: no session");
459 /* Allocate pipes for communicating with the program. */
461 error("%s: pipe in: %.100s", __func__, strerror(errno));
464 if (pipe(pout) < 0) {
465 error("%s: pipe out: %.100s", __func__, strerror(errno));
470 if (pipe(perr) < 0) {
471 error("%s: pipe err: %.100s", __func__,
480 int inout[2], err[2];
483 fatal("do_exec_no_pty: no session");
485 /* Uses socket pairs to communicate with the program. */
486 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
487 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
490 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
491 error("%s: socketpair #2: %.100s", __func__,
499 session_proctitle(s);
501 /* Fork the child. */
502 switch ((pid = fork())) {
504 error("%s: fork: %.100s", __func__, strerror(errno));
522 /* Child. Reinitialize the log since the pid has changed. */
523 log_init(__progname, options.log_level,
524 options.log_facility, log_stderr);
527 * Create a new session and process group since the 4.4BSD
528 * setlogin() affects the entire process group.
531 error("setsid failed: %.100s", strerror(errno));
535 * Redirect stdin. We close the parent side of the socket
536 * pair, and make the child side the standard input.
539 if (dup2(pin[0], 0) < 0)
540 perror("dup2 stdin");
543 /* Redirect stdout. */
545 if (dup2(pout[1], 1) < 0)
546 perror("dup2 stdout");
549 /* Redirect stderr. */
551 if (dup2(perr[1], 2) < 0)
552 perror("dup2 stderr");
556 * Redirect stdin, stdout, and stderr. Stdin and stdout will
557 * use the same socket, as some programs (particularly rdist)
558 * seem to depend on it.
562 if (dup2(inout[0], 0) < 0) /* stdin */
563 perror("dup2 stdin");
564 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
565 perror("dup2 stdout");
567 if (dup2(err[0], 2) < 0) /* stderr */
568 perror("dup2 stderr");
574 cray_init_job(s->pw); /* set up cray jid and tmpdir */
577 /* Do processing for the child (exec command etc). */
578 do_child(s, command);
585 signal(WJSIGNAL, cray_job_termination_handler);
588 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
592 /* Set interactive/non-interactive mode. */
593 packet_set_interactive(s->display != NULL,
594 options.ip_qos_interactive, options.ip_qos_bulk);
597 * Clear loginmsg, since it's the child's responsibility to display
598 * it to the user, otherwise multiple sessions may accumulate
599 * multiple copies of the login messages.
601 buffer_clear(&loginmsg);
604 /* We are the parent. Close the child sides of the pipes. */
610 session_set_fds(s, pin[1], pout[0], perr[0],
613 /* Enter the interactive session. */
614 server_loop(pid, pin[1], pout[0], perr[0]);
615 /* server_loop has closed pin[1], pout[0], and perr[0]. */
618 /* We are the parent. Close the child sides of the socket pairs. */
623 * Enter the interactive session. Note: server_loop must be able to
624 * handle the case that fdin and fdout are the same.
627 session_set_fds(s, inout[1], inout[1], err[1],
630 server_loop(pid, inout[1], inout[1], err[1]);
631 /* server_loop has closed inout[1] and err[1]. */
638 * This is called to fork and execute a command when we have a tty. This
639 * will call do_child from the child, and server_loop from the parent after
640 * setting up file descriptors, controlling tty, updating wtmp, utmp,
641 * lastlog, and other such operations.
644 do_exec_pty(Session *s, const char *command)
646 int fdout, ptyfd, ttyfd, ptymaster;
650 fatal("do_exec_pty: no session");
655 * Create another descriptor of the pty master side for use as the
656 * standard input. We could use the original descriptor, but this
657 * simplifies code in server_loop. The descriptor is bidirectional.
658 * Do this before forking (and cleanup in the child) so as to
659 * detect and gracefully fail out-of-fd conditions.
661 if ((fdout = dup(ptyfd)) < 0) {
662 error("%s: dup #1: %s", __func__, strerror(errno));
667 /* we keep a reference to the pty master */
668 if ((ptymaster = dup(ptyfd)) < 0) {
669 error("%s: dup #2: %s", __func__, strerror(errno));
676 /* Fork the child. */
677 switch ((pid = fork())) {
679 error("%s: fork: %.100s", __func__, strerror(errno));
691 /* Child. Reinitialize the log because the pid has changed. */
692 log_init(__progname, options.log_level,
693 options.log_facility, log_stderr);
694 /* Close the master side of the pseudo tty. */
697 /* Make the pseudo tty our controlling tty. */
698 pty_make_controlling_tty(&ttyfd, s->tty);
700 /* Redirect stdin/stdout/stderr from the pseudo tty. */
701 if (dup2(ttyfd, 0) < 0)
702 error("dup2 stdin: %s", strerror(errno));
703 if (dup2(ttyfd, 1) < 0)
704 error("dup2 stdout: %s", strerror(errno));
705 if (dup2(ttyfd, 2) < 0)
706 error("dup2 stderr: %s", strerror(errno));
708 /* Close the extra descriptor for the pseudo tty. */
711 /* record login, etc. similar to login(1) */
713 if (!(options.use_login && command == NULL)) {
715 cray_init_job(s->pw); /* set up cray jid and tmpdir */
717 do_login(s, command);
719 # ifdef LOGIN_NEEDS_UTMPX
725 * Do common processing for the child, such as execing
728 do_child(s, command);
735 signal(WJSIGNAL, cray_job_termination_handler);
738 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
743 /* Parent. Close the slave side of the pseudo tty. */
746 /* Enter interactive session. */
747 s->ptymaster = ptymaster;
748 packet_set_interactive(1,
749 options.ip_qos_interactive, options.ip_qos_bulk);
751 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
753 server_loop(pid, ptyfd, fdout, -1);
754 /* server_loop _has_ closed ptyfd and fdout. */
759 #ifdef LOGIN_NEEDS_UTMPX
761 do_pre_login(Session *s)
764 struct sockaddr_storage from;
765 pid_t pid = getpid();
768 * Get IP address of client. If the connection is not a socket, let
769 * the address be 0.0.0.0.
771 memset(&from, 0, sizeof(from));
772 fromlen = sizeof(from);
773 if (packet_connection_is_on_socket()) {
774 if (getpeername(packet_get_connection_in(),
775 (struct sockaddr *)&from, &fromlen) < 0) {
776 debug("getpeername: %.100s", strerror(errno));
781 record_utmp_only(pid, s->tty, s->pw->pw_name,
782 get_remote_name_or_ip(utmp_len, options.use_dns),
783 (struct sockaddr *)&from, fromlen);
788 * This is called to fork and execute a command. If another command is
789 * to be forced, execute that instead.
792 do_exec(Session *s, const char *command)
796 if (options.adm_forced_command) {
797 original_command = command;
798 command = options.adm_forced_command;
799 if (IS_INTERNAL_SFTP(command)) {
800 s->is_subsystem = s->is_subsystem ?
801 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
802 } else if (s->is_subsystem)
803 s->is_subsystem = SUBSYSTEM_EXT;
804 debug("Forced command (config) '%.900s'", command);
805 } else if (forced_command) {
806 original_command = command;
807 command = forced_command;
808 if (IS_INTERNAL_SFTP(command)) {
809 s->is_subsystem = s->is_subsystem ?
810 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
811 } else if (s->is_subsystem)
812 s->is_subsystem = SUBSYSTEM_EXT;
813 debug("Forced command (key option) '%.900s'", command);
816 #ifdef SSH_AUDIT_EVENTS
818 PRIVSEP(audit_run_command(command));
819 else if (s->ttyfd == -1) {
820 char *shell = s->pw->pw_shell;
822 if (shell[0] == '\0') /* empty shell means /bin/sh */
824 PRIVSEP(audit_run_command(shell));
828 ret = do_exec_pty(s, command);
830 ret = do_exec_no_pty(s, command);
832 original_command = NULL;
835 * Clear loginmsg: it's the child's responsibility to display
836 * it to the user, otherwise multiple sessions may accumulate
837 * multiple copies of the login messages.
839 buffer_clear(&loginmsg);
844 /* administrative, login(1)-like work */
846 do_login(Session *s, const char *command)
849 struct sockaddr_storage from;
850 struct passwd * pw = s->pw;
851 pid_t pid = getpid();
854 * Get IP address of client. If the connection is not a socket, let
855 * the address be 0.0.0.0.
857 memset(&from, 0, sizeof(from));
858 fromlen = sizeof(from);
859 if (packet_connection_is_on_socket()) {
860 if (getpeername(packet_get_connection_in(),
861 (struct sockaddr *)&from, &fromlen) < 0) {
862 debug("getpeername: %.100s", strerror(errno));
867 /* Record that there was a login on that tty from the remote host. */
869 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
870 get_remote_name_or_ip(utmp_len,
872 (struct sockaddr *)&from, fromlen);
876 * If password change is needed, do it now.
877 * This needs to occur before the ~/.hushlogin check.
879 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
882 s->authctxt->force_pwchange = 0;
883 /* XXX - signal [net] parent to enable forwardings */
887 if (check_quietlogin(s, command))
896 * Display the message of the day.
904 if (options.print_motd) {
905 #ifdef HAVE_LOGIN_CAP
906 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
909 f = fopen("/etc/motd", "r");
912 while (fgets(buf, sizeof(buf), f))
921 * Check for quiet login, either .hushlogin or command given.
924 check_quietlogin(Session *s, const char *command)
927 struct passwd *pw = s->pw;
930 /* Return 1 if .hushlogin exists or a command given. */
933 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
934 #ifdef HAVE_LOGIN_CAP
935 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
938 if (stat(buf, &st) >= 0)
945 * Sets the value of the given variable in the environment. If the variable
946 * already exists, its value is overridden.
949 child_set_env(char ***envp, u_int *envsizep, const char *name,
957 * If we're passed an uninitialized list, allocate a single null
958 * entry before continuing.
960 if (*envp == NULL && *envsizep == 0) {
961 *envp = xmalloc(sizeof(char *));
967 * Find the slot where the value should be stored. If the variable
968 * already exists, we reuse the slot; otherwise we append a new slot
969 * at the end of the array, expanding if necessary.
972 namelen = strlen(name);
973 for (i = 0; env[i]; i++)
974 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
977 /* Reuse the slot. */
980 /* New variable. Expand if necessary. */
982 if (i >= envsize - 1) {
984 fatal("child_set_env: too many env vars");
986 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
989 /* Need to set the NULL pointer at end of array beyond the new slot. */
993 /* Allocate space and format the variable in the appropriate slot. */
994 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
995 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
999 * Reads environment variables from the given file and adds/overrides them
1000 * into the environment. If the file does not exist, this does nothing.
1001 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1002 * and assignments of the form name=value. No other forms are allowed.
1005 read_environment_file(char ***env, u_int *envsize,
1006 const char *filename)
1013 f = fopen(filename, "r");
1017 while (fgets(buf, sizeof(buf), f)) {
1018 if (++lineno > 1000)
1019 fatal("Too many lines in environment file %s", filename);
1020 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1022 if (!*cp || *cp == '#' || *cp == '\n')
1025 cp[strcspn(cp, "\n")] = '\0';
1027 value = strchr(cp, '=');
1028 if (value == NULL) {
1029 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1034 * Replace the equals sign by nul, and advance value to
1039 child_set_env(env, envsize, cp, value);
1044 #ifdef HAVE_ETC_DEFAULT_LOGIN
1046 * Return named variable from specified environment, or NULL if not present.
1049 child_get_env(char **env, const char *name)
1055 for (i=0; env[i] != NULL; i++)
1056 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1057 return(env[i] + len + 1);
1062 * Read /etc/default/login.
1063 * We pick up the PATH (or SUPATH for root) and UMASK.
1066 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1068 char **tmpenv = NULL, *var;
1069 u_int i, tmpenvsize = 0;
1073 * We don't want to copy the whole file to the child's environment,
1074 * so we use a temporary environment and copy the variables we're
1077 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1083 var = child_get_env(tmpenv, "SUPATH");
1085 var = child_get_env(tmpenv, "PATH");
1087 child_set_env(env, envsize, "PATH", var);
1089 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1090 if (sscanf(var, "%5lo", &mask) == 1)
1091 umask((mode_t)mask);
1093 for (i = 0; tmpenv[i] != NULL; i++)
1097 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1100 copy_environment(char **source, char ***env, u_int *envsize)
1102 char *var_name, *var_val;
1108 for(i = 0; source[i] != NULL; i++) {
1109 var_name = xstrdup(source[i]);
1110 if ((var_val = strstr(var_name, "=")) == NULL) {
1116 debug3("Copy environment: %s=%s", var_name, var_val);
1117 child_set_env(env, envsize, var_name, var_val);
1124 do_setup_env(Session *s, const char *shell)
1129 struct passwd *pw = s->pw;
1130 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1133 extern char **environ;
1137 /* Initialize the environment. */
1139 env = xcalloc(envsize, sizeof(char *));
1144 * The Windows environment contains some setting which are
1145 * important for a running system. They must not be dropped.
1150 p = fetch_windows_environment();
1151 copy_environment(p, &env, &envsize);
1152 free_windows_environment(p);
1157 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1160 /* Allow any GSSAPI methods that we've used to alter
1161 * the childs environment as they see fit
1163 ssh_gssapi_do_child(&env, &envsize);
1166 if (!options.use_login) {
1167 /* Set basic environment. */
1168 for (i = 0; i < s->num_env; i++)
1169 child_set_env(&env, &envsize, s->env[i].name,
1172 child_set_env(&env, &envsize, "USER", pw->pw_name);
1173 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1175 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1177 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1178 snprintf(buf, sizeof buf, "%.200s/%.50s",
1179 _PATH_MAILDIR, pw->pw_name);
1180 child_set_env(&env, &envsize, "MAIL", buf);
1181 #ifdef HAVE_LOGIN_CAP
1182 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1183 child_set_env(&env, &envsize, "TERM", "su");
1185 environ = xmalloc(sizeof(char *));
1187 (void) setusercontext(lc, pw, pw->pw_uid,
1188 LOGIN_SETENV|LOGIN_SETPATH);
1189 copy_environment(environ, &env, &envsize);
1190 for (var = environ; *var != NULL; ++var)
1194 #else /* HAVE_LOGIN_CAP */
1195 # ifndef HAVE_CYGWIN
1197 * There's no standard path on Windows. The path contains
1198 * important components pointing to the system directories,
1199 * needed for loading shared libraries. So the path better
1200 * remains intact here.
1202 # ifdef HAVE_ETC_DEFAULT_LOGIN
1203 read_etc_default_login(&env, &envsize, pw->pw_uid);
1204 path = child_get_env(env, "PATH");
1205 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1206 if (path == NULL || *path == '\0') {
1207 child_set_env(&env, &envsize, "PATH",
1208 s->pw->pw_uid == 0 ?
1209 SUPERUSER_PATH : _PATH_STDPATH);
1211 # endif /* HAVE_CYGWIN */
1212 #endif /* HAVE_LOGIN_CAP */
1214 /* Normal systems set SHELL by default. */
1215 child_set_env(&env, &envsize, "SHELL", shell);
1218 /* Set custom environment options from RSA authentication. */
1219 if (!options.use_login) {
1220 while (custom_environment) {
1221 struct envstring *ce = custom_environment;
1224 for (i = 0; str[i] != '=' && str[i]; i++)
1226 if (str[i] == '=') {
1228 child_set_env(&env, &envsize, str, str + i + 1);
1230 custom_environment = ce->next;
1236 /* SSH_CLIENT deprecated */
1237 snprintf(buf, sizeof buf, "%.50s %d %d",
1238 get_remote_ipaddr(), get_remote_port(), get_local_port());
1239 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1241 laddr = get_local_ipaddr(packet_get_connection_in());
1242 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1243 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1245 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1248 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1250 child_set_env(&env, &envsize, "TERM", s->term);
1252 child_set_env(&env, &envsize, "DISPLAY", s->display);
1253 if (original_command)
1254 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1258 if (cray_tmpdir[0] != '\0')
1259 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1260 #endif /* _UNICOS */
1263 * Since we clear KRB5CCNAME at startup, if it's set now then it
1264 * must have been set by a native authentication method (eg AIX or
1265 * SIA), so copy it to the child.
1270 if ((cp = getenv("KRB5CCNAME")) != NULL)
1271 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1278 if ((cp = getenv("AUTHSTATE")) != NULL)
1279 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1280 read_environment_file(&env, &envsize, "/etc/environment");
1284 if (s->authctxt->krb5_ccname)
1285 child_set_env(&env, &envsize, "KRB5CCNAME",
1286 s->authctxt->krb5_ccname);
1290 * Pull in any environment variables that may have
1293 if (options.use_pam) {
1296 p = fetch_pam_child_environment();
1297 copy_environment(p, &env, &envsize);
1298 free_pam_environment(p);
1300 p = fetch_pam_environment();
1301 copy_environment(p, &env, &envsize);
1302 free_pam_environment(p);
1304 #endif /* USE_PAM */
1306 if (auth_sock_name != NULL)
1307 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1310 /* read $HOME/.ssh/environment. */
1311 if (options.permit_user_env && !options.use_login) {
1312 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1313 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1314 read_environment_file(&env, &envsize, buf);
1317 /* dump the environment */
1318 fprintf(stderr, "Environment:\n");
1319 for (i = 0; env[i]; i++)
1320 fprintf(stderr, " %.200s\n", env[i]);
1326 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1327 * first in this order).
1330 do_rc_files(Session *s, const char *shell)
1338 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1340 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1341 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1342 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1343 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1344 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1346 fprintf(stderr, "Running %s\n", cmd);
1347 f = popen(cmd, "w");
1350 fprintf(f, "%s %s\n", s->auth_proto,
1354 fprintf(stderr, "Could not run %s\n",
1356 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1358 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1359 _PATH_SSH_SYSTEM_RC);
1360 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1363 fprintf(f, "%s %s\n", s->auth_proto,
1367 fprintf(stderr, "Could not run %s\n",
1368 _PATH_SSH_SYSTEM_RC);
1369 } else if (do_xauth && options.xauth_location != NULL) {
1370 /* Add authority data to .Xauthority if appropriate. */
1373 "Running %.500s remove %.100s\n",
1374 options.xauth_location, s->auth_display);
1376 "%.500s add %.100s %.100s %.100s\n",
1377 options.xauth_location, s->auth_display,
1378 s->auth_proto, s->auth_data);
1380 snprintf(cmd, sizeof cmd, "%s -q -",
1381 options.xauth_location);
1382 f = popen(cmd, "w");
1384 fprintf(f, "remove %s\n",
1386 fprintf(f, "add %s %s %s\n",
1387 s->auth_display, s->auth_proto,
1391 fprintf(stderr, "Could not run %s\n",
1398 do_nologin(struct passwd *pw)
1401 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1404 #ifdef HAVE_LOGIN_CAP
1405 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1407 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1409 if (pw->pw_uid == 0)
1413 if (stat(nl, &sb) == -1) {
1419 /* /etc/nologin exists. Print its contents if we can and exit. */
1420 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1421 if ((f = fopen(nl, "r")) != NULL) {
1422 while (fgets(buf, sizeof(buf), f))
1430 * Chroot into a directory after checking it for safety: all path components
1431 * must be root-owned directories with strict permissions.
1434 safely_chroot(const char *path, uid_t uid)
1437 char component[MAXPATHLEN];
1441 fatal("chroot path does not begin at root");
1442 if (strlen(path) >= sizeof(component))
1443 fatal("chroot path too long");
1446 * Descend the path, checking that each component is a
1447 * root-owned directory with strict permissions.
1449 for (cp = path; cp != NULL;) {
1450 if ((cp = strchr(cp, '/')) == NULL)
1451 strlcpy(component, path, sizeof(component));
1454 memcpy(component, path, cp - path);
1455 component[cp - path] = '\0';
1458 debug3("%s: checking '%s'", __func__, component);
1460 if (stat(component, &st) != 0)
1461 fatal("%s: stat(\"%s\"): %s", __func__,
1462 component, strerror(errno));
1463 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1464 fatal("bad ownership or modes for chroot "
1465 "directory %s\"%s\"",
1466 cp == NULL ? "" : "component ", component);
1467 if (!S_ISDIR(st.st_mode))
1468 fatal("chroot path %s\"%s\" is not a directory",
1469 cp == NULL ? "" : "component ", component);
1473 if (chdir(path) == -1)
1474 fatal("Unable to chdir to chroot path \"%s\": "
1475 "%s", path, strerror(errno));
1476 if (chroot(path) == -1)
1477 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1478 if (chdir("/") == -1)
1479 fatal("%s: chdir(/) after chroot: %s",
1480 __func__, strerror(errno));
1481 verbose("Changed root directory to \"%s\"", path);
1484 /* Set login name, uid, gid, and groups. */
1486 do_setusercontext(struct passwd *pw)
1488 char *chroot_path, *tmp;
1490 platform_setusercontext(pw);
1492 if (platform_privileged_uidswap()) {
1493 #ifdef HAVE_LOGIN_CAP
1494 if (setusercontext(lc, pw, pw->pw_uid,
1495 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1496 perror("unable to set user context");
1500 if (setlogin(pw->pw_name) < 0)
1501 error("setlogin failed: %s", strerror(errno));
1502 if (setgid(pw->pw_gid) < 0) {
1506 /* Initialize the group list. */
1507 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1508 perror("initgroups");
1514 platform_setusercontext_post_groups(pw);
1516 if (options.chroot_directory != NULL &&
1517 strcasecmp(options.chroot_directory, "none") != 0) {
1518 tmp = tilde_expand_filename(options.chroot_directory,
1520 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1521 "u", pw->pw_name, (char *)NULL);
1522 safely_chroot(chroot_path, pw->pw_uid);
1527 #ifdef HAVE_LOGIN_CAP
1528 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1529 perror("unable to set user context (setuser)");
1533 /* Permanently switch to the desired uid. */
1534 permanently_set_uid(pw);
1538 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1539 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1543 do_pwchange(Session *s)
1546 fprintf(stderr, "WARNING: Your password has expired.\n");
1547 if (s->ttyfd != -1) {
1549 "You must change your password now and login again!\n");
1553 #ifdef PASSWD_NEEDS_USERNAME
1554 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1557 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1562 "Password change required but no TTY available.\n");
1568 launch_login(struct passwd *pw, const char *hostname)
1570 /* Launch login(1). */
1572 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1573 #ifdef xxxLOGIN_NEEDS_TERM
1574 (s->term ? s->term : "unknown"),
1575 #endif /* LOGIN_NEEDS_TERM */
1576 #ifdef LOGIN_NO_ENDOPT
1577 "-p", "-f", pw->pw_name, (char *)NULL);
1579 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1582 /* Login couldn't be executed, die. */
1589 child_close_fds(void)
1591 if (packet_get_connection_in() == packet_get_connection_out())
1592 close(packet_get_connection_in());
1594 close(packet_get_connection_in());
1595 close(packet_get_connection_out());
1598 * Close all descriptors related to channels. They will still remain
1599 * open in the parent.
1601 /* XXX better use close-on-exec? -markus */
1602 channel_close_all();
1605 * Close any extra file descriptors. Note that there may still be
1606 * descriptors left by system functions. They will be closed later.
1611 * Close any extra open file descriptors so that we don't have them
1612 * hanging around in clients. Note that we want to do this after
1613 * initgroups, because at least on Solaris 2.3 it leaves file
1616 closefrom(STDERR_FILENO + 1);
1620 * Performs common processing for the child, such as setting up the
1621 * environment, closing extra file descriptors, setting the user and group
1622 * ids, and executing the command or shell.
1626 do_child(Session *s, const char *command)
1628 extern char **environ;
1630 char *argv[ARGV_MAX];
1631 const char *shell, *shell0, *hostname = NULL;
1632 struct passwd *pw = s->pw;
1635 /* remove hostkey from the child's memory */
1636 destroy_sensitive_data();
1638 /* Force a password change */
1639 if (s->authctxt->force_pwchange) {
1640 do_setusercontext(pw);
1646 /* login(1) is only called if we execute the login shell */
1647 if (options.use_login && command != NULL)
1648 options.use_login = 0;
1651 cray_setup(pw->pw_uid, pw->pw_name, command);
1652 #endif /* _UNICOS */
1655 * Login(1) does this as well, and it needs uid 0 for the "-h"
1656 * switch, so we let login(1) to this for us.
1658 if (!options.use_login) {
1660 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1661 if (!check_quietlogin(s, command))
1663 #else /* HAVE_OSF_SIA */
1664 /* When PAM is enabled we rely on it to do the nologin check */
1665 if (!options.use_pam)
1667 do_setusercontext(pw);
1669 * PAM session modules in do_setusercontext may have
1670 * generated messages, so if this in an interactive
1671 * login then display them too.
1673 if (!check_quietlogin(s, command))
1675 #endif /* HAVE_OSF_SIA */
1679 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1680 debug3("PAM session not opened, exiting");
1687 * Get the shell from the password data. An empty shell field is
1688 * legal, and means /bin/sh.
1690 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1693 * Make sure $SHELL points to the shell from the password file,
1694 * even if shell is overridden from login.conf
1696 env = do_setup_env(s, shell);
1698 #ifdef HAVE_LOGIN_CAP
1699 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1702 /* we have to stash the hostname before we close our socket. */
1703 if (options.use_login)
1704 hostname = get_remote_name_or_ip(utmp_len,
1707 * Close the connection descriptors; note that this is the child, and
1708 * the server will still have the socket open, and it is important
1709 * that we do not shutdown it. Note that the descriptors cannot be
1710 * closed before building the environment, as we call
1711 * get_remote_ipaddr there.
1716 * Must take new environment into use so that .ssh/rc,
1717 * /etc/ssh/sshrc and xauth are run in the proper environment.
1721 #if defined(KRB5) && defined(USE_AFS)
1723 * At this point, we check to see if AFS is active and if we have
1724 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1725 * if we can (and need to) extend the ticket into an AFS token. If
1726 * we don't do this, we run into potential problems if the user's
1727 * home directory is in AFS and it's not world-readable.
1730 if (options.kerberos_get_afs_token && k_hasafs() &&
1731 (s->authctxt->krb5_ctx != NULL)) {
1734 debug("Getting AFS token");
1738 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1739 krb5_afslog(s->authctxt->krb5_ctx,
1740 s->authctxt->krb5_fwd_ccache, cell, NULL);
1742 krb5_afslog_home(s->authctxt->krb5_ctx,
1743 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1747 /* Change current directory to the user's home directory. */
1748 if (chdir(pw->pw_dir) < 0) {
1749 /* Suppress missing homedir warning for chroot case */
1750 #ifdef HAVE_LOGIN_CAP
1751 r = login_getcapbool(lc, "requirehome", 0);
1753 if (r || options.chroot_directory == NULL ||
1754 strcasecmp(options.chroot_directory, "none") == 0)
1755 fprintf(stderr, "Could not chdir to home "
1756 "directory %s: %s\n", pw->pw_dir,
1762 closefrom(STDERR_FILENO + 1);
1764 if (!options.use_login)
1765 do_rc_files(s, shell);
1767 /* restore SIGPIPE for child */
1768 signal(SIGPIPE, SIG_DFL);
1770 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1771 printf("This service allows sftp connections only.\n");
1774 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1775 extern int optind, optreset;
1779 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1780 args = xstrdup(command ? command : "sftp-server");
1781 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1782 if (i < ARGV_MAX - 1)
1785 optind = optreset = 1;
1786 __progname = argv[0];
1788 ssh_selinux_change_context("sftpd_t");
1790 exit(sftp_server_main(i, argv, s->pw));
1795 if (options.use_login) {
1796 launch_login(pw, hostname);
1800 /* Get the last component of the shell name. */
1801 if ((shell0 = strrchr(shell, '/')) != NULL)
1807 * If we have no command, execute the shell. In this case, the shell
1808 * name to be passed in argv[0] is preceded by '-' to indicate that
1809 * this is a login shell.
1814 /* Start the shell. Set initial character to '-'. */
1817 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1818 >= sizeof(argv0) - 1) {
1824 /* Execute the shell. */
1827 execve(shell, argv, env);
1829 /* Executing the shell failed. */
1834 * Execute the command using the user's shell. This uses the -c
1835 * option to execute the command.
1837 argv[0] = (char *) shell0;
1839 argv[2] = (char *) command;
1841 execve(shell, argv, env);
1847 session_unused(int id)
1849 debug3("%s: session id %d unused", __func__, id);
1850 if (id >= options.max_sessions ||
1851 id >= sessions_nalloc) {
1852 fatal("%s: insane session id %d (max %d nalloc %d)",
1853 __func__, id, options.max_sessions, sessions_nalloc);
1855 bzero(&sessions[id], sizeof(*sessions));
1856 sessions[id].self = id;
1857 sessions[id].used = 0;
1858 sessions[id].chanid = -1;
1859 sessions[id].ptyfd = -1;
1860 sessions[id].ttyfd = -1;
1861 sessions[id].ptymaster = -1;
1862 sessions[id].x11_chanids = NULL;
1863 sessions[id].next_unused = sessions_first_unused;
1864 sessions_first_unused = id;
1872 if (sessions_first_unused == -1) {
1873 if (sessions_nalloc >= options.max_sessions)
1875 debug2("%s: allocate (allocated %d max %d)",
1876 __func__, sessions_nalloc, options.max_sessions);
1877 tmp = xrealloc(sessions, sessions_nalloc + 1,
1880 error("%s: cannot allocate %d sessions",
1881 __func__, sessions_nalloc + 1);
1885 session_unused(sessions_nalloc++);
1888 if (sessions_first_unused >= sessions_nalloc ||
1889 sessions_first_unused < 0) {
1890 fatal("%s: insane first_unused %d max %d nalloc %d",
1891 __func__, sessions_first_unused, options.max_sessions,
1895 s = &sessions[sessions_first_unused];
1897 fatal("%s: session %d already used",
1898 __func__, sessions_first_unused);
1900 sessions_first_unused = s->next_unused;
1902 s->next_unused = -1;
1903 debug("session_new: session %d", s->self);
1912 for (i = 0; i < sessions_nalloc; i++) {
1913 Session *s = &sessions[i];
1915 debug("dump: used %d next_unused %d session %d %p "
1916 "channel %d pid %ld",
1927 session_open(Authctxt *authctxt, int chanid)
1929 Session *s = session_new();
1930 debug("session_open: channel %d", chanid);
1932 error("no more sessions");
1935 s->authctxt = authctxt;
1936 s->pw = authctxt->pw;
1937 if (s->pw == NULL || !authctxt->valid)
1938 fatal("no user for session %d", s->self);
1939 debug("session_open: session %d: link with channel %d", s->self, chanid);
1945 session_by_tty(char *tty)
1948 for (i = 0; i < sessions_nalloc; i++) {
1949 Session *s = &sessions[i];
1950 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1951 debug("session_by_tty: session %d tty %s", i, tty);
1955 debug("session_by_tty: unknown tty %.100s", tty);
1961 session_by_channel(int id)
1964 for (i = 0; i < sessions_nalloc; i++) {
1965 Session *s = &sessions[i];
1966 if (s->used && s->chanid == id) {
1967 debug("session_by_channel: session %d channel %d",
1972 debug("session_by_channel: unknown channel %d", id);
1978 session_by_x11_channel(int id)
1982 for (i = 0; i < sessions_nalloc; i++) {
1983 Session *s = &sessions[i];
1985 if (s->x11_chanids == NULL || !s->used)
1987 for (j = 0; s->x11_chanids[j] != -1; j++) {
1988 if (s->x11_chanids[j] == id) {
1989 debug("session_by_x11_channel: session %d "
1990 "channel %d", s->self, id);
1995 debug("session_by_x11_channel: unknown channel %d", id);
2001 session_by_pid(pid_t pid)
2004 debug("session_by_pid: pid %ld", (long)pid);
2005 for (i = 0; i < sessions_nalloc; i++) {
2006 Session *s = &sessions[i];
2007 if (s->used && s->pid == pid)
2010 error("session_by_pid: unknown pid %ld", (long)pid);
2016 session_window_change_req(Session *s)
2018 s->col = packet_get_int();
2019 s->row = packet_get_int();
2020 s->xpixel = packet_get_int();
2021 s->ypixel = packet_get_int();
2023 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2028 session_pty_req(Session *s)
2034 debug("Allocating a pty not permitted for this authentication.");
2037 if (s->ttyfd != -1) {
2038 packet_disconnect("Protocol error: you already have a pty.");
2042 s->term = packet_get_string(&len);
2045 s->col = packet_get_int();
2046 s->row = packet_get_int();
2048 s->row = packet_get_int();
2049 s->col = packet_get_int();
2051 s->xpixel = packet_get_int();
2052 s->ypixel = packet_get_int();
2054 if (strcmp(s->term, "") == 0) {
2059 /* Allocate a pty and open it. */
2060 debug("Allocating pty.");
2061 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2068 error("session_pty_req: session %d alloc failed", s->self);
2071 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2073 /* for SSH1 the tty modes length is not given */
2075 n_bytes = packet_remaining();
2076 tty_parse_modes(s->ttyfd, &n_bytes);
2079 pty_setowner(s->pw, s->tty);
2081 /* Set window size from the packet. */
2082 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2085 session_proctitle(s);
2090 session_subsystem_req(Session *s)
2095 char *prog, *cmd, *subsys = packet_get_string(&len);
2099 logit("subsystem request for %.100s by user %s", subsys,
2102 for (i = 0; i < options.num_subsystems; i++) {
2103 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2104 prog = options.subsystem_command[i];
2105 cmd = options.subsystem_args[i];
2106 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2107 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2108 debug("subsystem: %s", prog);
2110 if (stat(prog, &st) < 0)
2111 debug("subsystem: cannot stat %s: %s",
2112 prog, strerror(errno));
2113 s->is_subsystem = SUBSYSTEM_EXT;
2114 debug("subsystem: exec() %s", cmd);
2116 success = do_exec(s, cmd) == 0;
2122 logit("subsystem request for %.100s failed, subsystem not found",
2130 session_x11_req(Session *s)
2134 if (s->auth_proto != NULL || s->auth_data != NULL) {
2135 error("session_x11_req: session %d: "
2136 "x11 forwarding already active", s->self);
2139 s->single_connection = packet_get_char();
2140 s->auth_proto = packet_get_string(NULL);
2141 s->auth_data = packet_get_string(NULL);
2142 s->screen = packet_get_int();
2145 success = session_setup_x11fwd(s);
2147 xfree(s->auth_proto);
2148 xfree(s->auth_data);
2149 s->auth_proto = NULL;
2150 s->auth_data = NULL;
2156 session_shell_req(Session *s)
2159 return do_exec(s, NULL) == 0;
2163 session_exec_req(Session *s)
2167 char *command = packet_get_string(&len);
2169 success = do_exec(s, command) == 0;
2175 session_break_req(Session *s)
2178 packet_get_int(); /* ignored */
2181 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2187 session_env_req(Session *s)
2190 u_int name_len, val_len, i;
2192 name = packet_get_string(&name_len);
2193 val = packet_get_string(&val_len);
2196 /* Don't set too many environment variables */
2197 if (s->num_env > 128) {
2198 debug2("Ignoring env request %s: too many env vars", name);
2202 for (i = 0; i < options.num_accept_env; i++) {
2203 if (match_pattern(name, options.accept_env[i])) {
2204 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2205 s->env = xrealloc(s->env, s->num_env + 1,
2207 s->env[s->num_env].name = name;
2208 s->env[s->num_env].val = val;
2213 debug2("Ignoring env request %s: disallowed name", name);
2222 session_auth_agent_req(Session *s)
2224 static int called = 0;
2226 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2227 debug("session_auth_agent_req: no_agent_forwarding_flag");
2234 return auth_input_request_forwarding(s->pw);
2239 session_input_channel_req(Channel *c, const char *rtype)
2244 if ((s = session_by_channel(c->self)) == NULL) {
2245 logit("session_input_channel_req: no session %d req %.100s",
2249 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2252 * a session is in LARVAL state until a shell, a command
2253 * or a subsystem is executed
2255 if (c->type == SSH_CHANNEL_LARVAL) {
2256 if (strcmp(rtype, "shell") == 0) {
2257 success = session_shell_req(s);
2258 } else if (strcmp(rtype, "exec") == 0) {
2259 success = session_exec_req(s);
2260 } else if (strcmp(rtype, "pty-req") == 0) {
2261 success = session_pty_req(s);
2262 } else if (strcmp(rtype, "x11-req") == 0) {
2263 success = session_x11_req(s);
2264 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2265 success = session_auth_agent_req(s);
2266 } else if (strcmp(rtype, "subsystem") == 0) {
2267 success = session_subsystem_req(s);
2268 } else if (strcmp(rtype, "env") == 0) {
2269 success = session_env_req(s);
2272 if (strcmp(rtype, "window-change") == 0) {
2273 success = session_window_change_req(s);
2274 } else if (strcmp(rtype, "break") == 0) {
2275 success = session_break_req(s);
2282 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2286 fatal("session_set_fds: called for proto != 2.0");
2288 * now that have a child and a pipe to the child,
2289 * we can activate our channel and register the fd's
2291 if (s->chanid == -1)
2292 fatal("no channel for session %d", s->self);
2293 channel_set_fds(s->chanid,
2295 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2296 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2300 * Function to perform pty cleanup. Also called if we get aborted abnormally
2301 * (e.g., due to a dropped connection).
2304 session_pty_cleanup2(Session *s)
2307 error("session_pty_cleanup: no session");
2313 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2315 /* Record that the user has logged out. */
2317 record_logout(s->pid, s->tty, s->pw->pw_name);
2319 /* Release the pseudo-tty. */
2321 pty_release(s->tty);
2324 * Close the server side of the socket pairs. We must do this after
2325 * the pty cleanup, so that another process doesn't get this pty
2326 * while we're still cleaning up.
2328 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2329 error("close(s->ptymaster/%d): %s",
2330 s->ptymaster, strerror(errno));
2332 /* unlink pty from session */
2337 session_pty_cleanup(Session *s)
2339 PRIVSEP(session_pty_cleanup2(s));
2345 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2360 return "SIG@openssh.com";
2364 session_close_x11(int id)
2368 if ((c = channel_by_id(id)) == NULL) {
2369 debug("session_close_x11: x11 channel %d missing", id);
2371 /* Detach X11 listener */
2372 debug("session_close_x11: detach x11 channel %d", id);
2373 channel_cancel_cleanup(id);
2374 if (c->ostate != CHAN_OUTPUT_CLOSED)
2380 session_close_single_x11(int id, void *arg)
2385 debug3("session_close_single_x11: channel %d", id);
2386 channel_cancel_cleanup(id);
2387 if ((s = session_by_x11_channel(id)) == NULL)
2388 fatal("session_close_single_x11: no x11 channel %d", id);
2389 for (i = 0; s->x11_chanids[i] != -1; i++) {
2390 debug("session_close_single_x11: session %d: "
2391 "closing channel %d", s->self, s->x11_chanids[i]);
2393 * The channel "id" is already closing, but make sure we
2394 * close all of its siblings.
2396 if (s->x11_chanids[i] != id)
2397 session_close_x11(s->x11_chanids[i]);
2399 xfree(s->x11_chanids);
2400 s->x11_chanids = NULL;
2405 if (s->auth_proto) {
2406 xfree(s->auth_proto);
2407 s->auth_proto = NULL;
2410 xfree(s->auth_data);
2411 s->auth_data = NULL;
2413 if (s->auth_display) {
2414 xfree(s->auth_display);
2415 s->auth_display = NULL;
2420 session_exit_message(Session *s, int status)
2424 if ((c = channel_lookup(s->chanid)) == NULL)
2425 fatal("session_exit_message: session %d: no channel %d",
2426 s->self, s->chanid);
2427 debug("session_exit_message: session %d channel %d pid %ld",
2428 s->self, s->chanid, (long)s->pid);
2430 if (WIFEXITED(status)) {
2431 channel_request_start(s->chanid, "exit-status", 0);
2432 packet_put_int(WEXITSTATUS(status));
2434 } else if (WIFSIGNALED(status)) {
2435 channel_request_start(s->chanid, "exit-signal", 0);
2436 packet_put_cstring(sig2name(WTERMSIG(status)));
2438 packet_put_char(WCOREDUMP(status)? 1 : 0);
2439 #else /* WCOREDUMP */
2441 #endif /* WCOREDUMP */
2442 packet_put_cstring("");
2443 packet_put_cstring("");
2446 /* Some weird exit cause. Just exit. */
2447 packet_disconnect("wait returned status %04x.", status);
2450 /* disconnect channel */
2451 debug("session_exit_message: release channel %d", s->chanid);
2454 * Adjust cleanup callback attachment to send close messages when
2455 * the channel gets EOF. The session will be then be closed
2456 * by session_close_by_channel when the childs close their fds.
2458 channel_register_cleanup(c->self, session_close_by_channel, 1);
2461 * emulate a write failure with 'chan_write_failed', nobody will be
2462 * interested in data we write.
2463 * Note that we must not call 'chan_read_failed', since there could
2464 * be some more data waiting in the pipe.
2466 if (c->ostate != CHAN_OUTPUT_CLOSED)
2467 chan_write_failed(c);
2471 session_close(Session *s)
2475 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2477 session_pty_cleanup(s);
2483 xfree(s->x11_chanids);
2484 if (s->auth_display)
2485 xfree(s->auth_display);
2487 xfree(s->auth_data);
2489 xfree(s->auth_proto);
2490 if (s->env != NULL) {
2491 for (i = 0; i < s->num_env; i++) {
2492 xfree(s->env[i].name);
2493 xfree(s->env[i].val);
2497 session_proctitle(s);
2498 session_unused(s->self);
2502 session_close_by_pid(pid_t pid, int status)
2504 Session *s = session_by_pid(pid);
2506 debug("session_close_by_pid: no session for pid %ld",
2510 if (s->chanid != -1)
2511 session_exit_message(s, status);
2513 session_pty_cleanup(s);
2518 * this is called when a channel dies before
2519 * the session 'child' itself dies
2522 session_close_by_channel(int id, void *arg)
2524 Session *s = session_by_channel(id);
2528 debug("session_close_by_channel: no session for id %d", id);
2531 debug("session_close_by_channel: channel %d child %ld",
2534 debug("session_close_by_channel: channel %d: has child", id);
2536 * delay detach of session, but release pty, since
2537 * the fd's to the child are already closed
2540 session_pty_cleanup(s);
2543 /* detach by removing callback */
2544 channel_cancel_cleanup(s->chanid);
2546 /* Close any X11 listeners associated with this session */
2547 if (s->x11_chanids != NULL) {
2548 for (i = 0; s->x11_chanids[i] != -1; i++) {
2549 session_close_x11(s->x11_chanids[i]);
2550 s->x11_chanids[i] = -1;
2559 session_destroy_all(void (*closefunc)(Session *))
2562 for (i = 0; i < sessions_nalloc; i++) {
2563 Session *s = &sessions[i];
2565 if (closefunc != NULL)
2574 session_tty_list(void)
2576 static char buf[1024];
2581 for (i = 0; i < sessions_nalloc; i++) {
2582 Session *s = &sessions[i];
2583 if (s->used && s->ttyfd != -1) {
2585 if (strncmp(s->tty, "/dev/", 5) != 0) {
2586 cp = strrchr(s->tty, '/');
2587 cp = (cp == NULL) ? s->tty : cp + 1;
2592 strlcat(buf, ",", sizeof buf);
2593 strlcat(buf, cp, sizeof buf);
2597 strlcpy(buf, "notty", sizeof buf);
2602 session_proctitle(Session *s)
2605 error("no user for session %d", s->self);
2607 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2611 session_setup_x11fwd(Session *s)
2614 char display[512], auth_display[512];
2615 char hostname[MAXHOSTNAMELEN];
2618 if (no_x11_forwarding_flag) {
2619 packet_send_debug("X11 forwarding disabled in user configuration file.");
2622 if (!options.x11_forwarding) {
2623 debug("X11 forwarding disabled in server configuration file.");
2626 if (!options.xauth_location ||
2627 (stat(options.xauth_location, &st) == -1)) {
2628 packet_send_debug("No xauth program; cannot forward with spoofing.");
2631 if (options.use_login) {
2632 packet_send_debug("X11 forwarding disabled; "
2633 "not compatible with UseLogin=yes.");
2636 if (s->display != NULL) {
2637 debug("X11 display already set.");
2640 if (x11_create_display_inet(options.x11_display_offset,
2641 options.x11_use_localhost, s->single_connection,
2642 &s->display_number, &s->x11_chanids) == -1) {
2643 debug("x11_create_display_inet failed.");
2646 for (i = 0; s->x11_chanids[i] != -1; i++) {
2647 channel_register_cleanup(s->x11_chanids[i],
2648 session_close_single_x11, 0);
2651 /* Set up a suitable value for the DISPLAY variable. */
2652 if (gethostname(hostname, sizeof(hostname)) < 0)
2653 fatal("gethostname: %.100s", strerror(errno));
2655 * auth_display must be used as the displayname when the
2656 * authorization entry is added with xauth(1). This will be
2657 * different than the DISPLAY string for localhost displays.
2659 if (options.x11_use_localhost) {
2660 snprintf(display, sizeof display, "localhost:%u.%u",
2661 s->display_number, s->screen);
2662 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2663 s->display_number, s->screen);
2664 s->display = xstrdup(display);
2665 s->auth_display = xstrdup(auth_display);
2667 #ifdef IPADDR_IN_DISPLAY
2669 struct in_addr my_addr;
2671 he = gethostbyname(hostname);
2673 error("Can't get IP address for X11 DISPLAY.");
2674 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2677 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2678 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2679 s->display_number, s->screen);
2681 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2682 s->display_number, s->screen);
2684 s->display = xstrdup(display);
2685 s->auth_display = xstrdup(display);
2692 do_authenticated2(Authctxt *authctxt)
2694 server_loop2(authctxt);
2698 do_cleanup(Authctxt *authctxt)
2700 static int called = 0;
2702 debug("do_cleanup");
2704 /* no cleanup if we're in the child for login shell */
2708 /* avoid double cleanup */
2713 if (authctxt == NULL)
2717 if (options.use_pam) {
2719 sshpam_thread_cleanup();
2723 if (!authctxt->authenticated)
2727 if (options.kerberos_ticket_cleanup &&
2729 krb5_cleanup_proc(authctxt);
2733 if (compat20 && options.gss_cleanup_creds)
2734 ssh_gssapi_cleanup_creds();
2737 /* remove agent socket */
2738 auth_sock_cleanup_proc(authctxt->pw);
2741 * Cleanup ptys/utmp only if privsep is disabled,
2742 * or if running in monitor.
2744 if (!use_privsep || mm_is_monitor())
2745 session_destroy_all(session_pty_cleanup2);