1 /* $OpenBSD: session.c,v 1.270 2014/01/31 16:39:19 tedu 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"
85 #include "pathnames.h"
89 #include "serverloop.h"
94 #include "monitor_wrap.h"
97 #if defined(KRB5) && defined(USE_AFS)
102 #include <selinux/selinux.h>
105 #define IS_INTERNAL_SFTP(c) \
106 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
107 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
108 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
109 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
113 Session *session_new(void);
114 void session_set_fds(Session *, int, int, int, int, int);
115 void session_pty_cleanup(Session *);
116 void session_proctitle(Session *);
117 int session_setup_x11fwd(Session *);
118 int do_exec_pty(Session *, const char *);
119 int do_exec_no_pty(Session *, const char *);
120 int do_exec(Session *, const char *);
121 void do_login(Session *, const char *);
122 #ifdef LOGIN_NEEDS_UTMPX
123 static void do_pre_login(Session *s);
125 void do_child(Session *, const char *);
127 int check_quietlogin(Session *, const char *);
129 static void do_authenticated1(Authctxt *);
130 static void do_authenticated2(Authctxt *);
132 static int session_pty_req(Session *);
135 extern ServerOptions options;
136 extern char *__progname;
137 extern int log_stderr;
138 extern int debug_flag;
139 extern u_int utmp_len;
140 extern int startup_pipe;
141 extern void destroy_sensitive_data(void);
142 extern Buffer loginmsg;
144 /* original command from peer. */
145 const char *original_command = NULL;
148 static int sessions_first_unused = -1;
149 static int sessions_nalloc = 0;
150 static Session *sessions = NULL;
152 #define SUBSYSTEM_NONE 0
153 #define SUBSYSTEM_EXT 1
154 #define SUBSYSTEM_INT_SFTP 2
155 #define SUBSYSTEM_INT_SFTP_ERROR 3
157 #ifdef HAVE_LOGIN_CAP
161 static int is_child = 0;
163 /* Name and directory of socket for authentication agent forwarding. */
164 static char *auth_sock_name = NULL;
165 static char *auth_sock_dir = NULL;
167 /* removes the agent forwarding socket */
170 auth_sock_cleanup_proc(struct passwd *pw)
172 if (auth_sock_name != NULL) {
173 temporarily_use_uid(pw);
174 unlink(auth_sock_name);
175 rmdir(auth_sock_dir);
176 auth_sock_name = NULL;
182 auth_input_request_forwarding(struct passwd * pw)
186 struct sockaddr_un sunaddr;
188 if (auth_sock_name != NULL) {
189 error("authentication forwarding requested twice.");
193 /* Temporarily drop privileged uid for mkdir/bind. */
194 temporarily_use_uid(pw);
196 /* Allocate a buffer for the socket name, and format the name. */
197 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
199 /* Create private directory for socket */
200 if (mkdtemp(auth_sock_dir) == NULL) {
201 packet_send_debug("Agent forwarding disabled: "
202 "mkdtemp() failed: %.100s", strerror(errno));
205 auth_sock_dir = NULL;
209 xasprintf(&auth_sock_name, "%s/agent.%ld",
210 auth_sock_dir, (long) getpid());
212 /* Create the socket. */
213 sock = socket(AF_UNIX, SOCK_STREAM, 0);
215 error("socket: %.100s", strerror(errno));
220 /* Bind it to the name. */
221 memset(&sunaddr, 0, sizeof(sunaddr));
222 sunaddr.sun_family = AF_UNIX;
223 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path));
225 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
226 error("bind: %.100s", strerror(errno));
231 /* Restore the privileged uid. */
234 /* Start listening on the socket. */
235 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
236 error("listen: %.100s", strerror(errno));
240 /* Allocate a channel for the authentication agent socket. */
241 nc = channel_new("auth socket",
242 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
243 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
244 0, "auth socket", 1);
245 nc->path = xstrdup(auth_sock_name);
249 free(auth_sock_name);
250 if (auth_sock_dir != NULL) {
251 rmdir(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 ||
278 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
279 channel_disable_adm_local_opens();
281 channel_permit_all_opens();
286 do_authenticated2(authctxt);
288 do_authenticated1(authctxt);
290 do_cleanup(authctxt);
294 * Prepares for an interactive session. This is called after the user has
295 * been successfully authenticated. During this message exchange, pseudo
296 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
297 * are requested, etc.
300 do_authenticated1(Authctxt *authctxt)
304 int success, type, screen_flag;
305 int enable_compression_after_reply = 0;
306 u_int proto_len, data_len, dlen, compression_level = 0;
310 error("no more sessions");
313 s->authctxt = authctxt;
314 s->pw = authctxt->pw;
317 * We stay in this loop until the client requests to execute a shell
323 /* Get a packet from the client. */
324 type = packet_read();
326 /* Process the packet. */
328 case SSH_CMSG_REQUEST_COMPRESSION:
329 compression_level = packet_get_int();
331 if (compression_level < 1 || compression_level > 9) {
332 packet_send_debug("Received invalid compression level %d.",
336 if (options.compression == COMP_NONE) {
337 debug2("compression disabled");
340 /* Enable compression after we have responded with SUCCESS. */
341 enable_compression_after_reply = 1;
345 case SSH_CMSG_REQUEST_PTY:
346 success = session_pty_req(s);
349 case SSH_CMSG_X11_REQUEST_FORWARDING:
350 s->auth_proto = packet_get_string(&proto_len);
351 s->auth_data = packet_get_string(&data_len);
353 screen_flag = packet_get_protocol_flags() &
354 SSH_PROTOFLAG_SCREEN_NUMBER;
355 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
357 if (packet_remaining() == 4) {
359 debug2("Buggy client: "
360 "X11 screen flag missing");
361 s->screen = packet_get_int();
366 success = session_setup_x11fwd(s);
370 s->auth_proto = NULL;
375 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
376 if (!options.allow_agent_forwarding ||
377 no_agent_forwarding_flag || compat13) {
378 debug("Authentication agent forwarding not permitted for this authentication.");
381 debug("Received authentication agent forwarding request.");
382 success = auth_input_request_forwarding(s->pw);
385 case SSH_CMSG_PORT_FORWARD_REQUEST:
386 if (no_port_forwarding_flag) {
387 debug("Port forwarding not permitted for this authentication.");
390 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
391 debug("Port forwarding not permitted.");
394 debug("Received TCP/IP port forwarding request.");
395 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
396 options.gateway_ports) < 0) {
397 debug("Port forwarding failed.");
403 case SSH_CMSG_MAX_PACKET_SIZE:
404 if (packet_set_maxsize(packet_get_int()) > 0)
408 case SSH_CMSG_EXEC_SHELL:
409 case SSH_CMSG_EXEC_CMD:
410 if (type == SSH_CMSG_EXEC_CMD) {
411 command = packet_get_string(&dlen);
412 debug("Exec command '%.500s'", command);
413 if (do_exec(s, command) != 0)
415 "command execution failed");
418 if (do_exec(s, NULL) != 0)
420 "shell execution failed");
428 * Any unknown messages in this phase are ignored,
429 * and a failure message is returned.
431 logit("Unknown packet type received after authentication: %d", type);
433 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
437 /* Enable compression now that we have replied if appropriate. */
438 if (enable_compression_after_reply) {
439 enable_compression_after_reply = 0;
440 packet_start_compression(compression_level);
447 * This is called to fork and execute a command when we have no tty. This
448 * will call do_child from the child, and server_loop from the parent after
449 * setting up file descriptors and such.
452 do_exec_no_pty(Session *s, const char *command)
457 int pin[2], pout[2], perr[2];
460 fatal("do_exec_no_pty: no session");
462 /* Allocate pipes for communicating with the program. */
464 error("%s: pipe in: %.100s", __func__, strerror(errno));
467 if (pipe(pout) < 0) {
468 error("%s: pipe out: %.100s", __func__, strerror(errno));
473 if (pipe(perr) < 0) {
474 error("%s: pipe err: %.100s", __func__,
483 int inout[2], err[2];
486 fatal("do_exec_no_pty: no session");
488 /* Uses socket pairs to communicate with the program. */
489 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
490 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
493 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
494 error("%s: socketpair #2: %.100s", __func__,
502 session_proctitle(s);
504 /* Fork the child. */
505 switch ((pid = fork())) {
507 error("%s: fork: %.100s", __func__, strerror(errno));
525 /* Child. Reinitialize the log since the pid has changed. */
526 log_init(__progname, options.log_level,
527 options.log_facility, log_stderr);
530 * Create a new session and process group since the 4.4BSD
531 * setlogin() affects the entire process group.
534 error("setsid failed: %.100s", strerror(errno));
538 * Redirect stdin. We close the parent side of the socket
539 * pair, and make the child side the standard input.
542 if (dup2(pin[0], 0) < 0)
543 perror("dup2 stdin");
546 /* Redirect stdout. */
548 if (dup2(pout[1], 1) < 0)
549 perror("dup2 stdout");
552 /* Redirect stderr. */
554 if (dup2(perr[1], 2) < 0)
555 perror("dup2 stderr");
559 * Redirect stdin, stdout, and stderr. Stdin and stdout will
560 * use the same socket, as some programs (particularly rdist)
561 * seem to depend on it.
565 if (dup2(inout[0], 0) < 0) /* stdin */
566 perror("dup2 stdin");
567 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
568 perror("dup2 stdout");
570 if (dup2(err[0], 2) < 0) /* stderr */
571 perror("dup2 stderr");
577 cray_init_job(s->pw); /* set up cray jid and tmpdir */
580 /* Do processing for the child (exec command etc). */
581 do_child(s, command);
588 signal(WJSIGNAL, cray_job_termination_handler);
591 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
595 /* Set interactive/non-interactive mode. */
596 packet_set_interactive(s->display != NULL,
597 options.ip_qos_interactive, options.ip_qos_bulk);
600 * Clear loginmsg, since it's the child's responsibility to display
601 * it to the user, otherwise multiple sessions may accumulate
602 * multiple copies of the login messages.
604 buffer_clear(&loginmsg);
607 /* We are the parent. Close the child sides of the pipes. */
613 session_set_fds(s, pin[1], pout[0], perr[0],
616 /* Enter the interactive session. */
617 server_loop(pid, pin[1], pout[0], perr[0]);
618 /* server_loop has closed pin[1], pout[0], and perr[0]. */
621 /* We are the parent. Close the child sides of the socket pairs. */
626 * Enter the interactive session. Note: server_loop must be able to
627 * handle the case that fdin and fdout are the same.
630 session_set_fds(s, inout[1], inout[1], err[1],
633 server_loop(pid, inout[1], inout[1], err[1]);
634 /* server_loop has closed inout[1] and err[1]. */
641 * This is called to fork and execute a command when we have a tty. This
642 * will call do_child from the child, and server_loop from the parent after
643 * setting up file descriptors, controlling tty, updating wtmp, utmp,
644 * lastlog, and other such operations.
647 do_exec_pty(Session *s, const char *command)
649 int fdout, ptyfd, ttyfd, ptymaster;
653 fatal("do_exec_pty: no session");
658 * Create another descriptor of the pty master side for use as the
659 * standard input. We could use the original descriptor, but this
660 * simplifies code in server_loop. The descriptor is bidirectional.
661 * Do this before forking (and cleanup in the child) so as to
662 * detect and gracefully fail out-of-fd conditions.
664 if ((fdout = dup(ptyfd)) < 0) {
665 error("%s: dup #1: %s", __func__, strerror(errno));
670 /* we keep a reference to the pty master */
671 if ((ptymaster = dup(ptyfd)) < 0) {
672 error("%s: dup #2: %s", __func__, strerror(errno));
679 /* Fork the child. */
680 switch ((pid = fork())) {
682 error("%s: fork: %.100s", __func__, strerror(errno));
694 /* Child. Reinitialize the log because the pid has changed. */
695 log_init(__progname, options.log_level,
696 options.log_facility, log_stderr);
697 /* Close the master side of the pseudo tty. */
700 /* Make the pseudo tty our controlling tty. */
701 pty_make_controlling_tty(&ttyfd, s->tty);
703 /* Redirect stdin/stdout/stderr from the pseudo tty. */
704 if (dup2(ttyfd, 0) < 0)
705 error("dup2 stdin: %s", strerror(errno));
706 if (dup2(ttyfd, 1) < 0)
707 error("dup2 stdout: %s", strerror(errno));
708 if (dup2(ttyfd, 2) < 0)
709 error("dup2 stderr: %s", strerror(errno));
711 /* Close the extra descriptor for the pseudo tty. */
714 /* record login, etc. similar to login(1) */
716 if (!(options.use_login && command == NULL)) {
718 cray_init_job(s->pw); /* set up cray jid and tmpdir */
720 do_login(s, command);
722 # ifdef LOGIN_NEEDS_UTMPX
728 * Do common processing for the child, such as execing
731 do_child(s, command);
738 signal(WJSIGNAL, cray_job_termination_handler);
741 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
746 /* Parent. Close the slave side of the pseudo tty. */
749 /* Enter interactive session. */
750 s->ptymaster = ptymaster;
751 packet_set_interactive(1,
752 options.ip_qos_interactive, options.ip_qos_bulk);
754 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
756 server_loop(pid, ptyfd, fdout, -1);
757 /* server_loop _has_ closed ptyfd and fdout. */
762 #ifdef LOGIN_NEEDS_UTMPX
764 do_pre_login(Session *s)
767 struct sockaddr_storage from;
768 pid_t pid = getpid();
771 * Get IP address of client. If the connection is not a socket, let
772 * the address be 0.0.0.0.
774 memset(&from, 0, sizeof(from));
775 fromlen = sizeof(from);
776 if (packet_connection_is_on_socket()) {
777 if (getpeername(packet_get_connection_in(),
778 (struct sockaddr *)&from, &fromlen) < 0) {
779 debug("getpeername: %.100s", strerror(errno));
784 record_utmp_only(pid, s->tty, s->pw->pw_name,
785 get_remote_name_or_ip(utmp_len, options.use_dns),
786 (struct sockaddr *)&from, fromlen);
791 * This is called to fork and execute a command. If another command is
792 * to be forced, execute that instead.
795 do_exec(Session *s, const char *command)
798 const char *forced = NULL;
799 char session_type[1024], *tty = NULL;
801 if (options.adm_forced_command) {
802 original_command = command;
803 command = options.adm_forced_command;
805 } else if (forced_command) {
806 original_command = command;
807 command = forced_command;
808 forced = "(key-option)";
810 if (forced != NULL) {
811 if (IS_INTERNAL_SFTP(command)) {
812 s->is_subsystem = s->is_subsystem ?
813 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
814 } else if (s->is_subsystem)
815 s->is_subsystem = SUBSYSTEM_EXT;
816 snprintf(session_type, sizeof(session_type),
817 "forced-command %s '%.900s'", forced, command);
818 } else if (s->is_subsystem) {
819 snprintf(session_type, sizeof(session_type),
820 "subsystem '%.900s'", s->subsys);
821 } else if (command == NULL) {
822 snprintf(session_type, sizeof(session_type), "shell");
824 /* NB. we don't log unforced commands to preserve privacy */
825 snprintf(session_type, sizeof(session_type), "command");
828 if (s->ttyfd != -1) {
830 if (strncmp(tty, "/dev/", 5) == 0)
834 verbose("Starting session: %s%s%s for %s from %.200s port %d",
836 tty == NULL ? "" : " on ",
837 tty == NULL ? "" : tty,
842 #ifdef SSH_AUDIT_EVENTS
844 PRIVSEP(audit_run_command(command));
845 else if (s->ttyfd == -1) {
846 char *shell = s->pw->pw_shell;
848 if (shell[0] == '\0') /* empty shell means /bin/sh */
850 PRIVSEP(audit_run_command(shell));
854 ret = do_exec_pty(s, command);
856 ret = do_exec_no_pty(s, command);
858 original_command = NULL;
861 * Clear loginmsg: it's the child's responsibility to display
862 * it to the user, otherwise multiple sessions may accumulate
863 * multiple copies of the login messages.
865 buffer_clear(&loginmsg);
870 /* administrative, login(1)-like work */
872 do_login(Session *s, const char *command)
875 struct sockaddr_storage from;
876 struct passwd * pw = s->pw;
877 pid_t pid = getpid();
880 * Get IP address of client. If the connection is not a socket, let
881 * the address be 0.0.0.0.
883 memset(&from, 0, sizeof(from));
884 fromlen = sizeof(from);
885 if (packet_connection_is_on_socket()) {
886 if (getpeername(packet_get_connection_in(),
887 (struct sockaddr *)&from, &fromlen) < 0) {
888 debug("getpeername: %.100s", strerror(errno));
893 /* Record that there was a login on that tty from the remote host. */
895 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
896 get_remote_name_or_ip(utmp_len,
898 (struct sockaddr *)&from, fromlen);
902 * If password change is needed, do it now.
903 * This needs to occur before the ~/.hushlogin check.
905 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
908 s->authctxt->force_pwchange = 0;
909 /* XXX - signal [net] parent to enable forwardings */
913 if (check_quietlogin(s, command))
922 * Display the message of the day.
930 if (options.print_motd) {
931 #ifdef HAVE_LOGIN_CAP
932 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
935 f = fopen("/etc/motd", "r");
938 while (fgets(buf, sizeof(buf), f))
947 * Check for quiet login, either .hushlogin or command given.
950 check_quietlogin(Session *s, const char *command)
953 struct passwd *pw = s->pw;
956 /* Return 1 if .hushlogin exists or a command given. */
959 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
960 #ifdef HAVE_LOGIN_CAP
961 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
964 if (stat(buf, &st) >= 0)
971 * Sets the value of the given variable in the environment. If the variable
972 * already exists, its value is overridden.
975 child_set_env(char ***envp, u_int *envsizep, const char *name,
982 if (strchr(name, '=') != NULL) {
983 error("Invalid environment variable \"%.100s\"", name);
988 * If we're passed an uninitialized list, allocate a single null
989 * entry before continuing.
991 if (*envp == NULL && *envsizep == 0) {
992 *envp = xmalloc(sizeof(char *));
998 * Find the slot where the value should be stored. If the variable
999 * already exists, we reuse the slot; otherwise we append a new slot
1000 * at the end of the array, expanding if necessary.
1003 namelen = strlen(name);
1004 for (i = 0; env[i]; i++)
1005 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1008 /* Reuse the slot. */
1011 /* New variable. Expand if necessary. */
1012 envsize = *envsizep;
1013 if (i >= envsize - 1) {
1014 if (envsize >= 1000)
1015 fatal("child_set_env: too many env vars");
1017 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
1018 *envsizep = envsize;
1020 /* Need to set the NULL pointer at end of array beyond the new slot. */
1024 /* Allocate space and format the variable in the appropriate slot. */
1025 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1026 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1030 * Reads environment variables from the given file and adds/overrides them
1031 * into the environment. If the file does not exist, this does nothing.
1032 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1033 * and assignments of the form name=value. No other forms are allowed.
1036 read_environment_file(char ***env, u_int *envsize,
1037 const char *filename)
1044 f = fopen(filename, "r");
1048 while (fgets(buf, sizeof(buf), f)) {
1049 if (++lineno > 1000)
1050 fatal("Too many lines in environment file %s", filename);
1051 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1053 if (!*cp || *cp == '#' || *cp == '\n')
1056 cp[strcspn(cp, "\n")] = '\0';
1058 value = strchr(cp, '=');
1059 if (value == NULL) {
1060 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1065 * Replace the equals sign by nul, and advance value to
1070 child_set_env(env, envsize, cp, value);
1075 #ifdef HAVE_ETC_DEFAULT_LOGIN
1077 * Return named variable from specified environment, or NULL if not present.
1080 child_get_env(char **env, const char *name)
1086 for (i=0; env[i] != NULL; i++)
1087 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1088 return(env[i] + len + 1);
1093 * Read /etc/default/login.
1094 * We pick up the PATH (or SUPATH for root) and UMASK.
1097 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1099 char **tmpenv = NULL, *var;
1100 u_int i, tmpenvsize = 0;
1104 * We don't want to copy the whole file to the child's environment,
1105 * so we use a temporary environment and copy the variables we're
1108 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1114 var = child_get_env(tmpenv, "SUPATH");
1116 var = child_get_env(tmpenv, "PATH");
1118 child_set_env(env, envsize, "PATH", var);
1120 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1121 if (sscanf(var, "%5lo", &mask) == 1)
1122 umask((mode_t)mask);
1124 for (i = 0; tmpenv[i] != NULL; i++)
1128 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1131 copy_environment(char **source, char ***env, u_int *envsize)
1133 char *var_name, *var_val;
1139 for(i = 0; source[i] != NULL; i++) {
1140 var_name = xstrdup(source[i]);
1141 if ((var_val = strstr(var_name, "=")) == NULL) {
1147 debug3("Copy environment: %s=%s", var_name, var_val);
1148 child_set_env(env, envsize, var_name, var_val);
1155 do_setup_env(Session *s, const char *shell)
1160 struct passwd *pw = s->pw;
1161 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1164 extern char **environ;
1168 /* Initialize the environment. */
1170 env = xcalloc(envsize, sizeof(char *));
1175 * The Windows environment contains some setting which are
1176 * important for a running system. They must not be dropped.
1181 p = fetch_windows_environment();
1182 copy_environment(p, &env, &envsize);
1183 free_windows_environment(p);
1188 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1191 /* Allow any GSSAPI methods that we've used to alter
1192 * the childs environment as they see fit
1194 ssh_gssapi_do_child(&env, &envsize);
1197 if (!options.use_login) {
1198 /* Set basic environment. */
1199 for (i = 0; i < s->num_env; i++)
1200 child_set_env(&env, &envsize, s->env[i].name,
1203 child_set_env(&env, &envsize, "USER", pw->pw_name);
1204 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1206 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1208 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1209 snprintf(buf, sizeof buf, "%.200s/%.50s",
1210 _PATH_MAILDIR, pw->pw_name);
1211 child_set_env(&env, &envsize, "MAIL", buf);
1212 #ifdef HAVE_LOGIN_CAP
1213 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1214 child_set_env(&env, &envsize, "TERM", "su");
1216 environ = xmalloc(sizeof(char *));
1218 (void) setusercontext(lc, pw, pw->pw_uid,
1219 LOGIN_SETENV|LOGIN_SETPATH);
1220 copy_environment(environ, &env, &envsize);
1221 for (var = environ; *var != NULL; ++var)
1225 #else /* HAVE_LOGIN_CAP */
1226 # ifndef HAVE_CYGWIN
1228 * There's no standard path on Windows. The path contains
1229 * important components pointing to the system directories,
1230 * needed for loading shared libraries. So the path better
1231 * remains intact here.
1233 # ifdef HAVE_ETC_DEFAULT_LOGIN
1234 read_etc_default_login(&env, &envsize, pw->pw_uid);
1235 path = child_get_env(env, "PATH");
1236 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1237 if (path == NULL || *path == '\0') {
1238 child_set_env(&env, &envsize, "PATH",
1239 s->pw->pw_uid == 0 ?
1240 SUPERUSER_PATH : _PATH_STDPATH);
1242 # endif /* HAVE_CYGWIN */
1243 #endif /* HAVE_LOGIN_CAP */
1245 /* Normal systems set SHELL by default. */
1246 child_set_env(&env, &envsize, "SHELL", shell);
1249 /* Set custom environment options from RSA authentication. */
1250 if (!options.use_login) {
1251 while (custom_environment) {
1252 struct envstring *ce = custom_environment;
1255 for (i = 0; str[i] != '=' && str[i]; i++)
1257 if (str[i] == '=') {
1259 child_set_env(&env, &envsize, str, str + i + 1);
1261 custom_environment = ce->next;
1267 /* SSH_CLIENT deprecated */
1268 snprintf(buf, sizeof buf, "%.50s %d %d",
1269 get_remote_ipaddr(), get_remote_port(), get_local_port());
1270 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1272 laddr = get_local_ipaddr(packet_get_connection_in());
1273 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1274 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1276 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1279 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1281 child_set_env(&env, &envsize, "TERM", s->term);
1283 child_set_env(&env, &envsize, "DISPLAY", s->display);
1284 if (original_command)
1285 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1289 if (cray_tmpdir[0] != '\0')
1290 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1291 #endif /* _UNICOS */
1294 * Since we clear KRB5CCNAME at startup, if it's set now then it
1295 * must have been set by a native authentication method (eg AIX or
1296 * SIA), so copy it to the child.
1301 if ((cp = getenv("KRB5CCNAME")) != NULL)
1302 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1309 if ((cp = getenv("AUTHSTATE")) != NULL)
1310 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1311 read_environment_file(&env, &envsize, "/etc/environment");
1315 if (s->authctxt->krb5_ccname)
1316 child_set_env(&env, &envsize, "KRB5CCNAME",
1317 s->authctxt->krb5_ccname);
1321 * Pull in any environment variables that may have
1324 if (options.use_pam) {
1327 p = fetch_pam_child_environment();
1328 copy_environment(p, &env, &envsize);
1329 free_pam_environment(p);
1331 p = fetch_pam_environment();
1332 copy_environment(p, &env, &envsize);
1333 free_pam_environment(p);
1335 #endif /* USE_PAM */
1337 if (auth_sock_name != NULL)
1338 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1341 /* read $HOME/.ssh/environment. */
1342 if (options.permit_user_env && !options.use_login) {
1343 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1344 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1345 read_environment_file(&env, &envsize, buf);
1348 /* dump the environment */
1349 fprintf(stderr, "Environment:\n");
1350 for (i = 0; env[i]; i++)
1351 fprintf(stderr, " %.200s\n", env[i]);
1357 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1358 * first in this order).
1361 do_rc_files(Session *s, const char *shell)
1369 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1371 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1372 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1373 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1374 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1375 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1377 fprintf(stderr, "Running %s\n", cmd);
1378 f = popen(cmd, "w");
1381 fprintf(f, "%s %s\n", s->auth_proto,
1385 fprintf(stderr, "Could not run %s\n",
1387 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1389 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1390 _PATH_SSH_SYSTEM_RC);
1391 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1394 fprintf(f, "%s %s\n", s->auth_proto,
1398 fprintf(stderr, "Could not run %s\n",
1399 _PATH_SSH_SYSTEM_RC);
1400 } else if (do_xauth && options.xauth_location != NULL) {
1401 /* Add authority data to .Xauthority if appropriate. */
1404 "Running %.500s remove %.100s\n",
1405 options.xauth_location, s->auth_display);
1407 "%.500s add %.100s %.100s %.100s\n",
1408 options.xauth_location, s->auth_display,
1409 s->auth_proto, s->auth_data);
1411 snprintf(cmd, sizeof cmd, "%s -q -",
1412 options.xauth_location);
1413 f = popen(cmd, "w");
1415 fprintf(f, "remove %s\n",
1417 fprintf(f, "add %s %s %s\n",
1418 s->auth_display, s->auth_proto,
1422 fprintf(stderr, "Could not run %s\n",
1429 do_nologin(struct passwd *pw)
1432 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1435 #ifdef HAVE_LOGIN_CAP
1436 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1438 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1440 if (pw->pw_uid == 0)
1444 if (stat(nl, &sb) == -1) {
1450 /* /etc/nologin exists. Print its contents if we can and exit. */
1451 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1452 if ((f = fopen(nl, "r")) != NULL) {
1453 while (fgets(buf, sizeof(buf), f))
1461 * Chroot into a directory after checking it for safety: all path components
1462 * must be root-owned directories with strict permissions.
1465 safely_chroot(const char *path, uid_t uid)
1468 char component[MAXPATHLEN];
1472 fatal("chroot path does not begin at root");
1473 if (strlen(path) >= sizeof(component))
1474 fatal("chroot path too long");
1477 * Descend the path, checking that each component is a
1478 * root-owned directory with strict permissions.
1480 for (cp = path; cp != NULL;) {
1481 if ((cp = strchr(cp, '/')) == NULL)
1482 strlcpy(component, path, sizeof(component));
1485 memcpy(component, path, cp - path);
1486 component[cp - path] = '\0';
1489 debug3("%s: checking '%s'", __func__, component);
1491 if (stat(component, &st) != 0)
1492 fatal("%s: stat(\"%s\"): %s", __func__,
1493 component, strerror(errno));
1494 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1495 fatal("bad ownership or modes for chroot "
1496 "directory %s\"%s\"",
1497 cp == NULL ? "" : "component ", component);
1498 if (!S_ISDIR(st.st_mode))
1499 fatal("chroot path %s\"%s\" is not a directory",
1500 cp == NULL ? "" : "component ", component);
1504 if (chdir(path) == -1)
1505 fatal("Unable to chdir to chroot path \"%s\": "
1506 "%s", path, strerror(errno));
1507 if (chroot(path) == -1)
1508 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1509 if (chdir("/") == -1)
1510 fatal("%s: chdir(/) after chroot: %s",
1511 __func__, strerror(errno));
1512 verbose("Changed root directory to \"%s\"", path);
1515 /* Set login name, uid, gid, and groups. */
1517 do_setusercontext(struct passwd *pw)
1519 char *chroot_path, *tmp;
1521 platform_setusercontext(pw);
1523 if (platform_privileged_uidswap()) {
1524 #ifdef HAVE_LOGIN_CAP
1525 if (setusercontext(lc, pw, pw->pw_uid,
1526 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1527 perror("unable to set user context");
1531 if (setlogin(pw->pw_name) < 0)
1532 error("setlogin failed: %s", strerror(errno));
1533 if (setgid(pw->pw_gid) < 0) {
1537 /* Initialize the group list. */
1538 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1539 perror("initgroups");
1545 platform_setusercontext_post_groups(pw);
1547 if (options.chroot_directory != NULL &&
1548 strcasecmp(options.chroot_directory, "none") != 0) {
1549 tmp = tilde_expand_filename(options.chroot_directory,
1551 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1552 "u", pw->pw_name, (char *)NULL);
1553 safely_chroot(chroot_path, pw->pw_uid);
1556 /* Make sure we don't attempt to chroot again */
1557 free(options.chroot_directory);
1558 options.chroot_directory = NULL;
1561 #ifdef HAVE_LOGIN_CAP
1562 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1563 perror("unable to set user context (setuser)");
1567 * FreeBSD's setusercontext() will not apply the user's
1568 * own umask setting unless running with the user's UID.
1570 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK);
1573 if (set_id(pw->pw_name) != 0) {
1574 fatal("set_id(%s) Failed", pw->pw_name);
1576 # endif /* USE_LIBIAF */
1577 /* Permanently switch to the desired uid. */
1578 permanently_set_uid(pw);
1580 } else if (options.chroot_directory != NULL &&
1581 strcasecmp(options.chroot_directory, "none") != 0) {
1582 fatal("server lacks privileges to chroot to ChrootDirectory");
1585 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1586 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1590 do_pwchange(Session *s)
1593 fprintf(stderr, "WARNING: Your password has expired.\n");
1594 if (s->ttyfd != -1) {
1596 "You must change your password now and login again!\n");
1600 #ifdef PASSWD_NEEDS_USERNAME
1601 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1604 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1609 "Password change required but no TTY available.\n");
1615 launch_login(struct passwd *pw, const char *hostname)
1617 /* Launch login(1). */
1619 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1620 #ifdef xxxLOGIN_NEEDS_TERM
1621 (s->term ? s->term : "unknown"),
1622 #endif /* LOGIN_NEEDS_TERM */
1623 #ifdef LOGIN_NO_ENDOPT
1624 "-p", "-f", pw->pw_name, (char *)NULL);
1626 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1629 /* Login couldn't be executed, die. */
1636 child_close_fds(void)
1638 extern AuthenticationConnection *auth_conn;
1641 ssh_close_authentication_connection(auth_conn);
1645 if (packet_get_connection_in() == packet_get_connection_out())
1646 close(packet_get_connection_in());
1648 close(packet_get_connection_in());
1649 close(packet_get_connection_out());
1652 * Close all descriptors related to channels. They will still remain
1653 * open in the parent.
1655 /* XXX better use close-on-exec? -markus */
1656 channel_close_all();
1659 * Close any extra file descriptors. Note that there may still be
1660 * descriptors left by system functions. They will be closed later.
1665 * Close any extra open file descriptors so that we don't have them
1666 * hanging around in clients. Note that we want to do this after
1667 * initgroups, because at least on Solaris 2.3 it leaves file
1670 closefrom(STDERR_FILENO + 1);
1674 * Performs common processing for the child, such as setting up the
1675 * environment, closing extra file descriptors, setting the user and group
1676 * ids, and executing the command or shell.
1680 do_child(Session *s, const char *command)
1682 extern char **environ;
1684 char *argv[ARGV_MAX];
1685 const char *shell, *shell0, *hostname = NULL;
1686 struct passwd *pw = s->pw;
1689 /* remove hostkey from the child's memory */
1690 destroy_sensitive_data();
1692 /* Force a password change */
1693 if (s->authctxt->force_pwchange) {
1694 do_setusercontext(pw);
1700 /* login(1) is only called if we execute the login shell */
1701 if (options.use_login && command != NULL)
1702 options.use_login = 0;
1705 cray_setup(pw->pw_uid, pw->pw_name, command);
1706 #endif /* _UNICOS */
1709 * Login(1) does this as well, and it needs uid 0 for the "-h"
1710 * switch, so we let login(1) to this for us.
1712 if (!options.use_login) {
1714 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1715 if (!check_quietlogin(s, command))
1717 #else /* HAVE_OSF_SIA */
1718 /* When PAM is enabled we rely on it to do the nologin check */
1719 if (!options.use_pam)
1721 do_setusercontext(pw);
1723 * PAM session modules in do_setusercontext may have
1724 * generated messages, so if this in an interactive
1725 * login then display them too.
1727 if (!check_quietlogin(s, command))
1729 #endif /* HAVE_OSF_SIA */
1733 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1734 debug3("PAM session not opened, exiting");
1741 * Get the shell from the password data. An empty shell field is
1742 * legal, and means /bin/sh.
1744 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1747 * Make sure $SHELL points to the shell from the password file,
1748 * even if shell is overridden from login.conf
1750 env = do_setup_env(s, shell);
1752 #ifdef HAVE_LOGIN_CAP
1753 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1756 /* we have to stash the hostname before we close our socket. */
1757 if (options.use_login)
1758 hostname = get_remote_name_or_ip(utmp_len,
1761 * Close the connection descriptors; note that this is the child, and
1762 * the server will still have the socket open, and it is important
1763 * that we do not shutdown it. Note that the descriptors cannot be
1764 * closed before building the environment, as we call
1765 * get_remote_ipaddr there.
1770 * Must take new environment into use so that .ssh/rc,
1771 * /etc/ssh/sshrc and xauth are run in the proper environment.
1775 #if defined(KRB5) && defined(USE_AFS)
1777 * At this point, we check to see if AFS is active and if we have
1778 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1779 * if we can (and need to) extend the ticket into an AFS token. If
1780 * we don't do this, we run into potential problems if the user's
1781 * home directory is in AFS and it's not world-readable.
1784 if (options.kerberos_get_afs_token && k_hasafs() &&
1785 (s->authctxt->krb5_ctx != NULL)) {
1788 debug("Getting AFS token");
1792 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1793 krb5_afslog(s->authctxt->krb5_ctx,
1794 s->authctxt->krb5_fwd_ccache, cell, NULL);
1796 krb5_afslog_home(s->authctxt->krb5_ctx,
1797 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1801 /* Change current directory to the user's home directory. */
1802 if (chdir(pw->pw_dir) < 0) {
1803 /* Suppress missing homedir warning for chroot case */
1804 #ifdef HAVE_LOGIN_CAP
1805 r = login_getcapbool(lc, "requirehome", 0);
1807 if (r || options.chroot_directory == NULL ||
1808 strcasecmp(options.chroot_directory, "none") == 0)
1809 fprintf(stderr, "Could not chdir to home "
1810 "directory %s: %s\n", pw->pw_dir,
1816 closefrom(STDERR_FILENO + 1);
1818 if (!options.use_login)
1819 do_rc_files(s, shell);
1821 /* restore SIGPIPE for child */
1822 signal(SIGPIPE, SIG_DFL);
1824 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1825 printf("This service allows sftp connections only.\n");
1828 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1829 extern int optind, optreset;
1833 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1834 args = xstrdup(command ? command : "sftp-server");
1835 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1836 if (i < ARGV_MAX - 1)
1839 optind = optreset = 1;
1840 __progname = argv[0];
1842 ssh_selinux_change_context("sftpd_t");
1844 exit(sftp_server_main(i, argv, s->pw));
1849 if (options.use_login) {
1850 launch_login(pw, hostname);
1854 /* Get the last component of the shell name. */
1855 if ((shell0 = strrchr(shell, '/')) != NULL)
1861 * If we have no command, execute the shell. In this case, the shell
1862 * name to be passed in argv[0] is preceded by '-' to indicate that
1863 * this is a login shell.
1868 /* Start the shell. Set initial character to '-'. */
1871 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1872 >= sizeof(argv0) - 1) {
1878 /* Execute the shell. */
1881 execve(shell, argv, env);
1883 /* Executing the shell failed. */
1888 * Execute the command using the user's shell. This uses the -c
1889 * option to execute the command.
1891 argv[0] = (char *) shell0;
1893 argv[2] = (char *) command;
1895 execve(shell, argv, env);
1901 session_unused(int id)
1903 debug3("%s: session id %d unused", __func__, id);
1904 if (id >= options.max_sessions ||
1905 id >= sessions_nalloc) {
1906 fatal("%s: insane session id %d (max %d nalloc %d)",
1907 __func__, id, options.max_sessions, sessions_nalloc);
1909 memset(&sessions[id], 0, sizeof(*sessions));
1910 sessions[id].self = id;
1911 sessions[id].used = 0;
1912 sessions[id].chanid = -1;
1913 sessions[id].ptyfd = -1;
1914 sessions[id].ttyfd = -1;
1915 sessions[id].ptymaster = -1;
1916 sessions[id].x11_chanids = NULL;
1917 sessions[id].next_unused = sessions_first_unused;
1918 sessions_first_unused = id;
1926 if (sessions_first_unused == -1) {
1927 if (sessions_nalloc >= options.max_sessions)
1929 debug2("%s: allocate (allocated %d max %d)",
1930 __func__, sessions_nalloc, options.max_sessions);
1931 tmp = xrealloc(sessions, sessions_nalloc + 1,
1934 error("%s: cannot allocate %d sessions",
1935 __func__, sessions_nalloc + 1);
1939 session_unused(sessions_nalloc++);
1942 if (sessions_first_unused >= sessions_nalloc ||
1943 sessions_first_unused < 0) {
1944 fatal("%s: insane first_unused %d max %d nalloc %d",
1945 __func__, sessions_first_unused, options.max_sessions,
1949 s = &sessions[sessions_first_unused];
1951 fatal("%s: session %d already used",
1952 __func__, sessions_first_unused);
1954 sessions_first_unused = s->next_unused;
1956 s->next_unused = -1;
1957 debug("session_new: session %d", s->self);
1966 for (i = 0; i < sessions_nalloc; i++) {
1967 Session *s = &sessions[i];
1969 debug("dump: used %d next_unused %d session %d %p "
1970 "channel %d pid %ld",
1981 session_open(Authctxt *authctxt, int chanid)
1983 Session *s = session_new();
1984 debug("session_open: channel %d", chanid);
1986 error("no more sessions");
1989 s->authctxt = authctxt;
1990 s->pw = authctxt->pw;
1991 if (s->pw == NULL || !authctxt->valid)
1992 fatal("no user for session %d", s->self);
1993 debug("session_open: session %d: link with channel %d", s->self, chanid);
1999 session_by_tty(char *tty)
2002 for (i = 0; i < sessions_nalloc; i++) {
2003 Session *s = &sessions[i];
2004 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2005 debug("session_by_tty: session %d tty %s", i, tty);
2009 debug("session_by_tty: unknown tty %.100s", tty);
2015 session_by_channel(int id)
2018 for (i = 0; i < sessions_nalloc; i++) {
2019 Session *s = &sessions[i];
2020 if (s->used && s->chanid == id) {
2021 debug("session_by_channel: session %d channel %d",
2026 debug("session_by_channel: unknown channel %d", id);
2032 session_by_x11_channel(int id)
2036 for (i = 0; i < sessions_nalloc; i++) {
2037 Session *s = &sessions[i];
2039 if (s->x11_chanids == NULL || !s->used)
2041 for (j = 0; s->x11_chanids[j] != -1; j++) {
2042 if (s->x11_chanids[j] == id) {
2043 debug("session_by_x11_channel: session %d "
2044 "channel %d", s->self, id);
2049 debug("session_by_x11_channel: unknown channel %d", id);
2055 session_by_pid(pid_t pid)
2058 debug("session_by_pid: pid %ld", (long)pid);
2059 for (i = 0; i < sessions_nalloc; i++) {
2060 Session *s = &sessions[i];
2061 if (s->used && s->pid == pid)
2064 error("session_by_pid: unknown pid %ld", (long)pid);
2070 session_window_change_req(Session *s)
2072 s->col = packet_get_int();
2073 s->row = packet_get_int();
2074 s->xpixel = packet_get_int();
2075 s->ypixel = packet_get_int();
2077 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2082 session_pty_req(Session *s)
2087 if (no_pty_flag || !options.permit_tty) {
2088 debug("Allocating a pty not permitted for this authentication.");
2091 if (s->ttyfd != -1) {
2092 packet_disconnect("Protocol error: you already have a pty.");
2096 s->term = packet_get_string(&len);
2099 s->col = packet_get_int();
2100 s->row = packet_get_int();
2102 s->row = packet_get_int();
2103 s->col = packet_get_int();
2105 s->xpixel = packet_get_int();
2106 s->ypixel = packet_get_int();
2108 if (strcmp(s->term, "") == 0) {
2113 /* Allocate a pty and open it. */
2114 debug("Allocating pty.");
2115 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2121 error("session_pty_req: session %d alloc failed", s->self);
2124 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2126 /* for SSH1 the tty modes length is not given */
2128 n_bytes = packet_remaining();
2129 tty_parse_modes(s->ttyfd, &n_bytes);
2132 pty_setowner(s->pw, s->tty);
2134 /* Set window size from the packet. */
2135 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2138 session_proctitle(s);
2143 session_subsystem_req(Session *s)
2151 s->subsys = packet_get_string(&len);
2153 debug2("subsystem request for %.100s by user %s", s->subsys,
2156 for (i = 0; i < options.num_subsystems; i++) {
2157 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
2158 prog = options.subsystem_command[i];
2159 cmd = options.subsystem_args[i];
2160 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2161 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2162 debug("subsystem: %s", prog);
2164 if (stat(prog, &st) < 0)
2165 debug("subsystem: cannot stat %s: %s",
2166 prog, strerror(errno));
2167 s->is_subsystem = SUBSYSTEM_EXT;
2168 debug("subsystem: exec() %s", cmd);
2170 success = do_exec(s, cmd) == 0;
2176 logit("subsystem request for %.100s by user %s failed, "
2177 "subsystem not found", s->subsys, s->pw->pw_name);
2183 session_x11_req(Session *s)
2187 if (s->auth_proto != NULL || s->auth_data != NULL) {
2188 error("session_x11_req: session %d: "
2189 "x11 forwarding already active", s->self);
2192 s->single_connection = packet_get_char();
2193 s->auth_proto = packet_get_string(NULL);
2194 s->auth_data = packet_get_string(NULL);
2195 s->screen = packet_get_int();
2198 success = session_setup_x11fwd(s);
2200 free(s->auth_proto);
2202 s->auth_proto = NULL;
2203 s->auth_data = NULL;
2209 session_shell_req(Session *s)
2212 return do_exec(s, NULL) == 0;
2216 session_exec_req(Session *s)
2220 char *command = packet_get_string(&len);
2222 success = do_exec(s, command) == 0;
2228 session_break_req(Session *s)
2231 packet_get_int(); /* ignored */
2234 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2240 session_env_req(Session *s)
2243 u_int name_len, val_len, i;
2245 name = packet_get_cstring(&name_len);
2246 val = packet_get_cstring(&val_len);
2249 /* Don't set too many environment variables */
2250 if (s->num_env > 128) {
2251 debug2("Ignoring env request %s: too many env vars", name);
2255 for (i = 0; i < options.num_accept_env; i++) {
2256 if (match_pattern(name, options.accept_env[i])) {
2257 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2258 s->env = xrealloc(s->env, s->num_env + 1,
2260 s->env[s->num_env].name = name;
2261 s->env[s->num_env].val = val;
2266 debug2("Ignoring env request %s: disallowed name", name);
2275 session_auth_agent_req(Session *s)
2277 static int called = 0;
2279 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2280 debug("session_auth_agent_req: no_agent_forwarding_flag");
2287 return auth_input_request_forwarding(s->pw);
2292 session_input_channel_req(Channel *c, const char *rtype)
2297 if ((s = session_by_channel(c->self)) == NULL) {
2298 logit("session_input_channel_req: no session %d req %.100s",
2302 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2305 * a session is in LARVAL state until a shell, a command
2306 * or a subsystem is executed
2308 if (c->type == SSH_CHANNEL_LARVAL) {
2309 if (strcmp(rtype, "shell") == 0) {
2310 success = session_shell_req(s);
2311 } else if (strcmp(rtype, "exec") == 0) {
2312 success = session_exec_req(s);
2313 } else if (strcmp(rtype, "pty-req") == 0) {
2314 success = session_pty_req(s);
2315 } else if (strcmp(rtype, "x11-req") == 0) {
2316 success = session_x11_req(s);
2317 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2318 success = session_auth_agent_req(s);
2319 } else if (strcmp(rtype, "subsystem") == 0) {
2320 success = session_subsystem_req(s);
2321 } else if (strcmp(rtype, "env") == 0) {
2322 success = session_env_req(s);
2325 if (strcmp(rtype, "window-change") == 0) {
2326 success = session_window_change_req(s);
2327 } else if (strcmp(rtype, "break") == 0) {
2328 success = session_break_req(s);
2335 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2339 fatal("session_set_fds: called for proto != 2.0");
2341 * now that have a child and a pipe to the child,
2342 * we can activate our channel and register the fd's
2344 if (s->chanid == -1)
2345 fatal("no channel for session %d", s->self);
2346 channel_set_fds(s->chanid,
2348 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2349 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2353 * Function to perform pty cleanup. Also called if we get aborted abnormally
2354 * (e.g., due to a dropped connection).
2357 session_pty_cleanup2(Session *s)
2360 error("session_pty_cleanup: no session");
2366 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2368 /* Record that the user has logged out. */
2370 record_logout(s->pid, s->tty, s->pw->pw_name);
2372 /* Release the pseudo-tty. */
2374 pty_release(s->tty);
2377 * Close the server side of the socket pairs. We must do this after
2378 * the pty cleanup, so that another process doesn't get this pty
2379 * while we're still cleaning up.
2381 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2382 error("close(s->ptymaster/%d): %s",
2383 s->ptymaster, strerror(errno));
2385 /* unlink pty from session */
2390 session_pty_cleanup(Session *s)
2392 PRIVSEP(session_pty_cleanup2(s));
2398 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2413 return "SIG@openssh.com";
2417 session_close_x11(int id)
2421 if ((c = channel_by_id(id)) == NULL) {
2422 debug("session_close_x11: x11 channel %d missing", id);
2424 /* Detach X11 listener */
2425 debug("session_close_x11: detach x11 channel %d", id);
2426 channel_cancel_cleanup(id);
2427 if (c->ostate != CHAN_OUTPUT_CLOSED)
2433 session_close_single_x11(int id, void *arg)
2438 debug3("session_close_single_x11: channel %d", id);
2439 channel_cancel_cleanup(id);
2440 if ((s = session_by_x11_channel(id)) == NULL)
2441 fatal("session_close_single_x11: no x11 channel %d", id);
2442 for (i = 0; s->x11_chanids[i] != -1; i++) {
2443 debug("session_close_single_x11: session %d: "
2444 "closing channel %d", s->self, s->x11_chanids[i]);
2446 * The channel "id" is already closing, but make sure we
2447 * close all of its siblings.
2449 if (s->x11_chanids[i] != id)
2450 session_close_x11(s->x11_chanids[i]);
2452 free(s->x11_chanids);
2453 s->x11_chanids = NULL;
2456 free(s->auth_proto);
2457 s->auth_proto = NULL;
2459 s->auth_data = NULL;
2460 free(s->auth_display);
2461 s->auth_display = NULL;
2465 session_exit_message(Session *s, int status)
2469 if ((c = channel_lookup(s->chanid)) == NULL)
2470 fatal("session_exit_message: session %d: no channel %d",
2471 s->self, s->chanid);
2472 debug("session_exit_message: session %d channel %d pid %ld",
2473 s->self, s->chanid, (long)s->pid);
2475 if (WIFEXITED(status)) {
2476 channel_request_start(s->chanid, "exit-status", 0);
2477 packet_put_int(WEXITSTATUS(status));
2479 } else if (WIFSIGNALED(status)) {
2480 channel_request_start(s->chanid, "exit-signal", 0);
2481 packet_put_cstring(sig2name(WTERMSIG(status)));
2483 packet_put_char(WCOREDUMP(status)? 1 : 0);
2484 #else /* WCOREDUMP */
2486 #endif /* WCOREDUMP */
2487 packet_put_cstring("");
2488 packet_put_cstring("");
2491 /* Some weird exit cause. Just exit. */
2492 packet_disconnect("wait returned status %04x.", status);
2495 /* disconnect channel */
2496 debug("session_exit_message: release channel %d", s->chanid);
2499 * Adjust cleanup callback attachment to send close messages when
2500 * the channel gets EOF. The session will be then be closed
2501 * by session_close_by_channel when the childs close their fds.
2503 channel_register_cleanup(c->self, session_close_by_channel, 1);
2506 * emulate a write failure with 'chan_write_failed', nobody will be
2507 * interested in data we write.
2508 * Note that we must not call 'chan_read_failed', since there could
2509 * be some more data waiting in the pipe.
2511 if (c->ostate != CHAN_OUTPUT_CLOSED)
2512 chan_write_failed(c);
2516 session_close(Session *s)
2520 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2522 session_pty_cleanup(s);
2525 free(s->x11_chanids);
2526 free(s->auth_display);
2528 free(s->auth_proto);
2530 if (s->env != NULL) {
2531 for (i = 0; i < s->num_env; i++) {
2532 free(s->env[i].name);
2533 free(s->env[i].val);
2537 session_proctitle(s);
2538 session_unused(s->self);
2542 session_close_by_pid(pid_t pid, int status)
2544 Session *s = session_by_pid(pid);
2546 debug("session_close_by_pid: no session for pid %ld",
2550 if (s->chanid != -1)
2551 session_exit_message(s, status);
2553 session_pty_cleanup(s);
2558 * this is called when a channel dies before
2559 * the session 'child' itself dies
2562 session_close_by_channel(int id, void *arg)
2564 Session *s = session_by_channel(id);
2568 debug("session_close_by_channel: no session for id %d", id);
2571 debug("session_close_by_channel: channel %d child %ld",
2574 debug("session_close_by_channel: channel %d: has child", id);
2576 * delay detach of session, but release pty, since
2577 * the fd's to the child are already closed
2580 session_pty_cleanup(s);
2583 /* detach by removing callback */
2584 channel_cancel_cleanup(s->chanid);
2586 /* Close any X11 listeners associated with this session */
2587 if (s->x11_chanids != NULL) {
2588 for (i = 0; s->x11_chanids[i] != -1; i++) {
2589 session_close_x11(s->x11_chanids[i]);
2590 s->x11_chanids[i] = -1;
2599 session_destroy_all(void (*closefunc)(Session *))
2602 for (i = 0; i < sessions_nalloc; i++) {
2603 Session *s = &sessions[i];
2605 if (closefunc != NULL)
2614 session_tty_list(void)
2616 static char buf[1024];
2621 for (i = 0; i < sessions_nalloc; i++) {
2622 Session *s = &sessions[i];
2623 if (s->used && s->ttyfd != -1) {
2625 if (strncmp(s->tty, "/dev/", 5) != 0) {
2626 cp = strrchr(s->tty, '/');
2627 cp = (cp == NULL) ? s->tty : cp + 1;
2632 strlcat(buf, ",", sizeof buf);
2633 strlcat(buf, cp, sizeof buf);
2637 strlcpy(buf, "notty", sizeof buf);
2642 session_proctitle(Session *s)
2645 error("no user for session %d", s->self);
2647 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2651 session_setup_x11fwd(Session *s)
2654 char display[512], auth_display[512];
2655 char hostname[MAXHOSTNAMELEN];
2658 if (no_x11_forwarding_flag) {
2659 packet_send_debug("X11 forwarding disabled in user configuration file.");
2662 if (!options.x11_forwarding) {
2663 debug("X11 forwarding disabled in server configuration file.");
2666 if (!options.xauth_location ||
2667 (stat(options.xauth_location, &st) == -1)) {
2668 packet_send_debug("No xauth program; cannot forward with spoofing.");
2671 if (options.use_login) {
2672 packet_send_debug("X11 forwarding disabled; "
2673 "not compatible with UseLogin=yes.");
2676 if (s->display != NULL) {
2677 debug("X11 display already set.");
2680 if (x11_create_display_inet(options.x11_display_offset,
2681 options.x11_use_localhost, s->single_connection,
2682 &s->display_number, &s->x11_chanids) == -1) {
2683 debug("x11_create_display_inet failed.");
2686 for (i = 0; s->x11_chanids[i] != -1; i++) {
2687 channel_register_cleanup(s->x11_chanids[i],
2688 session_close_single_x11, 0);
2691 /* Set up a suitable value for the DISPLAY variable. */
2692 if (gethostname(hostname, sizeof(hostname)) < 0)
2693 fatal("gethostname: %.100s", strerror(errno));
2695 * auth_display must be used as the displayname when the
2696 * authorization entry is added with xauth(1). This will be
2697 * different than the DISPLAY string for localhost displays.
2699 if (options.x11_use_localhost) {
2700 snprintf(display, sizeof display, "localhost:%u.%u",
2701 s->display_number, s->screen);
2702 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2703 s->display_number, s->screen);
2704 s->display = xstrdup(display);
2705 s->auth_display = xstrdup(auth_display);
2707 #ifdef IPADDR_IN_DISPLAY
2709 struct in_addr my_addr;
2711 he = gethostbyname(hostname);
2713 error("Can't get IP address for X11 DISPLAY.");
2714 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2717 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2718 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2719 s->display_number, s->screen);
2721 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2722 s->display_number, s->screen);
2724 s->display = xstrdup(display);
2725 s->auth_display = xstrdup(display);
2732 do_authenticated2(Authctxt *authctxt)
2734 server_loop2(authctxt);
2738 do_cleanup(Authctxt *authctxt)
2740 static int called = 0;
2742 debug("do_cleanup");
2744 /* no cleanup if we're in the child for login shell */
2748 /* avoid double cleanup */
2753 if (authctxt == NULL)
2757 if (options.use_pam) {
2759 sshpam_thread_cleanup();
2763 if (!authctxt->authenticated)
2767 if (options.kerberos_ticket_cleanup &&
2769 krb5_cleanup_proc(authctxt);
2773 if (compat20 && options.gss_cleanup_creds)
2774 ssh_gssapi_cleanup_creds();
2777 /* remove agent socket */
2778 auth_sock_cleanup_proc(authctxt->pw);
2781 * Cleanup ptys/utmp only if privsep is disabled,
2782 * or if running in monitor.
2784 if (!use_privsep || mm_is_monitor())
2785 session_destroy_all(session_pty_cleanup2);