1 /* $OpenBSD: session.c,v 1.261 2012/12/02 20:46:11 djm Exp $ */
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
13 * SSH2 support by Markus Friedl.
14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution.
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 #include <sys/types.h>
41 #include <sys/param.h>
42 #ifdef HAVE_SYS_STAT_H
43 # include <sys/stat.h>
45 #include <sys/socket.h>
49 #include <arpa/inet.h>
65 #include "openbsd-compat/sys-queue.h"
84 #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));
204 xfree(auth_sock_dir);
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));
241 * Allocate a channel for the authentication agent socket.
242 * Ignore HPN on that one given no improvement expected.
244 nc = channel_new("auth socket",
245 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
246 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
247 0, "auth socket", 1);
248 nc->path = xstrdup(auth_sock_name);
252 if (auth_sock_name != NULL)
253 xfree(auth_sock_name);
254 if (auth_sock_dir != NULL) {
255 rmdir(auth_sock_dir);
256 xfree(auth_sock_dir);
260 auth_sock_name = NULL;
261 auth_sock_dir = NULL;
266 display_loginmsg(void)
268 if (buffer_len(&loginmsg) > 0) {
269 buffer_append(&loginmsg, "\0", 1);
270 printf("%s", (char *)buffer_ptr(&loginmsg));
271 buffer_clear(&loginmsg);
276 do_authenticated(Authctxt *authctxt)
278 setproctitle("%s", authctxt->pw->pw_name);
280 /* setup the channel layer */
281 if (no_port_forwarding_flag ||
282 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
283 channel_disable_adm_local_opens();
285 channel_permit_all_opens();
290 do_authenticated2(authctxt);
292 do_authenticated1(authctxt);
294 do_cleanup(authctxt);
298 * Prepares for an interactive session. This is called after the user has
299 * been successfully authenticated. During this message exchange, pseudo
300 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
301 * are requested, etc.
304 do_authenticated1(Authctxt *authctxt)
308 int success, type, screen_flag;
309 int enable_compression_after_reply = 0;
310 u_int proto_len, data_len, dlen, compression_level = 0;
314 error("no more sessions");
317 s->authctxt = authctxt;
318 s->pw = authctxt->pw;
321 * We stay in this loop until the client requests to execute a shell
327 /* Get a packet from the client. */
328 type = packet_read();
330 /* Process the packet. */
332 case SSH_CMSG_REQUEST_COMPRESSION:
333 compression_level = packet_get_int();
335 if (compression_level < 1 || compression_level > 9) {
336 packet_send_debug("Received invalid compression level %d.",
340 if (options.compression == COMP_NONE) {
341 debug2("compression disabled");
344 /* Enable compression after we have responded with SUCCESS. */
345 enable_compression_after_reply = 1;
349 case SSH_CMSG_REQUEST_PTY:
350 success = session_pty_req(s);
353 case SSH_CMSG_X11_REQUEST_FORWARDING:
354 s->auth_proto = packet_get_string(&proto_len);
355 s->auth_data = packet_get_string(&data_len);
357 screen_flag = packet_get_protocol_flags() &
358 SSH_PROTOFLAG_SCREEN_NUMBER;
359 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
361 if (packet_remaining() == 4) {
363 debug2("Buggy client: "
364 "X11 screen flag missing");
365 s->screen = packet_get_int();
370 success = session_setup_x11fwd(s);
372 xfree(s->auth_proto);
374 s->auth_proto = NULL;
379 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
380 if (!options.allow_agent_forwarding ||
381 no_agent_forwarding_flag || compat13) {
382 debug("Authentication agent forwarding not permitted for this authentication.");
385 debug("Received authentication agent forwarding request.");
386 success = auth_input_request_forwarding(s->pw);
389 case SSH_CMSG_PORT_FORWARD_REQUEST:
390 if (no_port_forwarding_flag) {
391 debug("Port forwarding not permitted for this authentication.");
394 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
395 debug("Port forwarding not permitted.");
398 debug("Received TCP/IP port forwarding request.");
399 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
400 options.gateway_ports) < 0) {
401 debug("Port forwarding failed.");
407 case SSH_CMSG_MAX_PACKET_SIZE:
408 if (packet_set_maxsize(packet_get_int()) > 0)
412 case SSH_CMSG_EXEC_SHELL:
413 case SSH_CMSG_EXEC_CMD:
414 if (type == SSH_CMSG_EXEC_CMD) {
415 command = packet_get_string(&dlen);
416 debug("Exec command '%.500s'", command);
417 if (do_exec(s, command) != 0)
419 "command execution failed");
422 if (do_exec(s, NULL) != 0)
424 "shell execution failed");
432 * Any unknown messages in this phase are ignored,
433 * and a failure message is returned.
435 logit("Unknown packet type received after authentication: %d", type);
437 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
441 /* Enable compression now that we have replied if appropriate. */
442 if (enable_compression_after_reply) {
443 enable_compression_after_reply = 0;
444 packet_start_compression(compression_level);
451 * This is called to fork and execute a command when we have no tty. This
452 * will call do_child from the child, and server_loop from the parent after
453 * setting up file descriptors and such.
456 do_exec_no_pty(Session *s, const char *command)
461 int pin[2], pout[2], perr[2];
464 fatal("do_exec_no_pty: no session");
466 /* Allocate pipes for communicating with the program. */
468 error("%s: pipe in: %.100s", __func__, strerror(errno));
471 if (pipe(pout) < 0) {
472 error("%s: pipe out: %.100s", __func__, strerror(errno));
477 if (pipe(perr) < 0) {
478 error("%s: pipe err: %.100s", __func__,
487 int inout[2], err[2];
490 fatal("do_exec_no_pty: no session");
492 /* Uses socket pairs to communicate with the program. */
493 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
494 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
497 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
498 error("%s: socketpair #2: %.100s", __func__,
506 session_proctitle(s);
508 /* Fork the child. */
509 switch ((pid = fork())) {
511 error("%s: fork: %.100s", __func__, strerror(errno));
529 /* Child. Reinitialize the log since the pid has changed. */
530 log_init(__progname, options.log_level,
531 options.log_facility, log_stderr);
534 * Create a new session and process group since the 4.4BSD
535 * setlogin() affects the entire process group.
538 error("setsid failed: %.100s", strerror(errno));
542 * Redirect stdin. We close the parent side of the socket
543 * pair, and make the child side the standard input.
546 if (dup2(pin[0], 0) < 0)
547 perror("dup2 stdin");
550 /* Redirect stdout. */
552 if (dup2(pout[1], 1) < 0)
553 perror("dup2 stdout");
556 /* Redirect stderr. */
558 if (dup2(perr[1], 2) < 0)
559 perror("dup2 stderr");
563 * Redirect stdin, stdout, and stderr. Stdin and stdout will
564 * use the same socket, as some programs (particularly rdist)
565 * seem to depend on it.
569 if (dup2(inout[0], 0) < 0) /* stdin */
570 perror("dup2 stdin");
571 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
572 perror("dup2 stdout");
574 if (dup2(err[0], 2) < 0) /* stderr */
575 perror("dup2 stderr");
581 cray_init_job(s->pw); /* set up cray jid and tmpdir */
584 /* Do processing for the child (exec command etc). */
585 do_child(s, command);
592 signal(WJSIGNAL, cray_job_termination_handler);
595 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
599 /* Set interactive/non-interactive mode. */
600 packet_set_interactive(s->display != NULL,
601 options.ip_qos_interactive, options.ip_qos_bulk);
604 * Clear loginmsg, since it's the child's responsibility to display
605 * it to the user, otherwise multiple sessions may accumulate
606 * multiple copies of the login messages.
608 buffer_clear(&loginmsg);
611 /* We are the parent. Close the child sides of the pipes. */
617 session_set_fds(s, pin[1], pout[0], perr[0],
620 /* Enter the interactive session. */
621 server_loop(pid, pin[1], pout[0], perr[0]);
622 /* server_loop has closed pin[1], pout[0], and perr[0]. */
625 /* We are the parent. Close the child sides of the socket pairs. */
630 * Enter the interactive session. Note: server_loop must be able to
631 * handle the case that fdin and fdout are the same.
634 session_set_fds(s, inout[1], inout[1], err[1],
637 server_loop(pid, inout[1], inout[1], err[1]);
638 /* server_loop has closed inout[1] and err[1]. */
645 * This is called to fork and execute a command when we have a tty. This
646 * will call do_child from the child, and server_loop from the parent after
647 * setting up file descriptors, controlling tty, updating wtmp, utmp,
648 * lastlog, and other such operations.
651 do_exec_pty(Session *s, const char *command)
653 int fdout, ptyfd, ttyfd, ptymaster;
657 fatal("do_exec_pty: no session");
662 * Create another descriptor of the pty master side for use as the
663 * standard input. We could use the original descriptor, but this
664 * simplifies code in server_loop. The descriptor is bidirectional.
665 * Do this before forking (and cleanup in the child) so as to
666 * detect and gracefully fail out-of-fd conditions.
668 if ((fdout = dup(ptyfd)) < 0) {
669 error("%s: dup #1: %s", __func__, strerror(errno));
674 /* we keep a reference to the pty master */
675 if ((ptymaster = dup(ptyfd)) < 0) {
676 error("%s: dup #2: %s", __func__, strerror(errno));
683 /* Fork the child. */
684 switch ((pid = fork())) {
686 error("%s: fork: %.100s", __func__, strerror(errno));
698 /* Child. Reinitialize the log because the pid has changed. */
699 log_init(__progname, options.log_level,
700 options.log_facility, log_stderr);
701 /* Close the master side of the pseudo tty. */
704 /* Make the pseudo tty our controlling tty. */
705 pty_make_controlling_tty(&ttyfd, s->tty);
707 /* Redirect stdin/stdout/stderr from the pseudo tty. */
708 if (dup2(ttyfd, 0) < 0)
709 error("dup2 stdin: %s", strerror(errno));
710 if (dup2(ttyfd, 1) < 0)
711 error("dup2 stdout: %s", strerror(errno));
712 if (dup2(ttyfd, 2) < 0)
713 error("dup2 stderr: %s", strerror(errno));
715 /* Close the extra descriptor for the pseudo tty. */
718 /* record login, etc. similar to login(1) */
720 if (!(options.use_login && command == NULL)) {
722 cray_init_job(s->pw); /* set up cray jid and tmpdir */
724 do_login(s, command);
726 # ifdef LOGIN_NEEDS_UTMPX
732 * Do common processing for the child, such as execing
735 do_child(s, command);
742 signal(WJSIGNAL, cray_job_termination_handler);
745 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
750 /* Parent. Close the slave side of the pseudo tty. */
753 /* Enter interactive session. */
754 s->ptymaster = ptymaster;
755 packet_set_interactive(1,
756 options.ip_qos_interactive, options.ip_qos_bulk);
758 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
760 server_loop(pid, ptyfd, fdout, -1);
761 /* server_loop _has_ closed ptyfd and fdout. */
766 #ifdef LOGIN_NEEDS_UTMPX
768 do_pre_login(Session *s)
771 struct sockaddr_storage from;
772 pid_t pid = getpid();
775 * Get IP address of client. If the connection is not a socket, let
776 * the address be 0.0.0.0.
778 memset(&from, 0, sizeof(from));
779 fromlen = sizeof(from);
780 if (packet_connection_is_on_socket()) {
781 if (getpeername(packet_get_connection_in(),
782 (struct sockaddr *)&from, &fromlen) < 0) {
783 debug("getpeername: %.100s", strerror(errno));
788 record_utmp_only(pid, s->tty, s->pw->pw_name,
789 get_remote_name_or_ip(utmp_len, options.use_dns),
790 (struct sockaddr *)&from, fromlen);
795 * This is called to fork and execute a command. If another command is
796 * to be forced, execute that instead.
799 do_exec(Session *s, const char *command)
803 if (options.adm_forced_command) {
804 original_command = command;
805 command = options.adm_forced_command;
806 if (IS_INTERNAL_SFTP(command)) {
807 s->is_subsystem = s->is_subsystem ?
808 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
809 } else if (s->is_subsystem)
810 s->is_subsystem = SUBSYSTEM_EXT;
811 debug("Forced command (config) '%.900s'", command);
812 } else if (forced_command) {
813 original_command = command;
814 command = forced_command;
815 if (IS_INTERNAL_SFTP(command)) {
816 s->is_subsystem = s->is_subsystem ?
817 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
818 } else if (s->is_subsystem)
819 s->is_subsystem = SUBSYSTEM_EXT;
820 debug("Forced command (key option) '%.900s'", command);
823 #ifdef SSH_AUDIT_EVENTS
825 PRIVSEP(audit_run_command(command));
826 else if (s->ttyfd == -1) {
827 char *shell = s->pw->pw_shell;
829 if (shell[0] == '\0') /* empty shell means /bin/sh */
831 PRIVSEP(audit_run_command(shell));
835 ret = do_exec_pty(s, command);
837 ret = do_exec_no_pty(s, command);
839 original_command = NULL;
842 * Clear loginmsg: it's the child's responsibility to display
843 * it to the user, otherwise multiple sessions may accumulate
844 * multiple copies of the login messages.
846 buffer_clear(&loginmsg);
851 /* administrative, login(1)-like work */
853 do_login(Session *s, const char *command)
856 struct sockaddr_storage from;
857 struct passwd * pw = s->pw;
858 pid_t pid = getpid();
861 * Get IP address of client. If the connection is not a socket, let
862 * the address be 0.0.0.0.
864 memset(&from, 0, sizeof(from));
865 fromlen = sizeof(from);
866 if (packet_connection_is_on_socket()) {
867 if (getpeername(packet_get_connection_in(),
868 (struct sockaddr *)&from, &fromlen) < 0) {
869 debug("getpeername: %.100s", strerror(errno));
874 /* Record that there was a login on that tty from the remote host. */
876 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
877 get_remote_name_or_ip(utmp_len,
879 (struct sockaddr *)&from, fromlen);
883 * If password change is needed, do it now.
884 * This needs to occur before the ~/.hushlogin check.
886 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
889 s->authctxt->force_pwchange = 0;
890 /* XXX - signal [net] parent to enable forwardings */
894 if (check_quietlogin(s, command))
903 * Display the message of the day.
911 if (options.print_motd) {
912 #ifdef HAVE_LOGIN_CAP
913 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
916 f = fopen("/etc/motd", "r");
919 while (fgets(buf, sizeof(buf), f))
928 * Check for quiet login, either .hushlogin or command given.
931 check_quietlogin(Session *s, const char *command)
934 struct passwd *pw = s->pw;
937 /* Return 1 if .hushlogin exists or a command given. */
940 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
941 #ifdef HAVE_LOGIN_CAP
942 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
945 if (stat(buf, &st) >= 0)
952 * Sets the value of the given variable in the environment. If the variable
953 * already exists, its value is overridden.
956 child_set_env(char ***envp, u_int *envsizep, const char *name,
964 * If we're passed an uninitialized list, allocate a single null
965 * entry before continuing.
967 if (*envp == NULL && *envsizep == 0) {
968 *envp = xmalloc(sizeof(char *));
974 * Find the slot where the value should be stored. If the variable
975 * already exists, we reuse the slot; otherwise we append a new slot
976 * at the end of the array, expanding if necessary.
979 namelen = strlen(name);
980 for (i = 0; env[i]; i++)
981 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
984 /* Reuse the slot. */
987 /* New variable. Expand if necessary. */
989 if (i >= envsize - 1) {
991 fatal("child_set_env: too many env vars");
993 env = (*envp) = xrealloc(env, envsize, sizeof(char *));
996 /* Need to set the NULL pointer at end of array beyond the new slot. */
1000 /* Allocate space and format the variable in the appropriate slot. */
1001 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1002 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1006 * Reads environment variables from the given file and adds/overrides them
1007 * into the environment. If the file does not exist, this does nothing.
1008 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1009 * and assignments of the form name=value. No other forms are allowed.
1012 read_environment_file(char ***env, u_int *envsize,
1013 const char *filename)
1020 f = fopen(filename, "r");
1024 while (fgets(buf, sizeof(buf), f)) {
1025 if (++lineno > 1000)
1026 fatal("Too many lines in environment file %s", filename);
1027 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1029 if (!*cp || *cp == '#' || *cp == '\n')
1032 cp[strcspn(cp, "\n")] = '\0';
1034 value = strchr(cp, '=');
1035 if (value == NULL) {
1036 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1041 * Replace the equals sign by nul, and advance value to
1046 child_set_env(env, envsize, cp, value);
1051 #ifdef HAVE_ETC_DEFAULT_LOGIN
1053 * Return named variable from specified environment, or NULL if not present.
1056 child_get_env(char **env, const char *name)
1062 for (i=0; env[i] != NULL; i++)
1063 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1064 return(env[i] + len + 1);
1069 * Read /etc/default/login.
1070 * We pick up the PATH (or SUPATH for root) and UMASK.
1073 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1075 char **tmpenv = NULL, *var;
1076 u_int i, tmpenvsize = 0;
1080 * We don't want to copy the whole file to the child's environment,
1081 * so we use a temporary environment and copy the variables we're
1084 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1090 var = child_get_env(tmpenv, "SUPATH");
1092 var = child_get_env(tmpenv, "PATH");
1094 child_set_env(env, envsize, "PATH", var);
1096 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1097 if (sscanf(var, "%5lo", &mask) == 1)
1098 umask((mode_t)mask);
1100 for (i = 0; tmpenv[i] != NULL; i++)
1104 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1107 copy_environment(char **source, char ***env, u_int *envsize)
1109 char *var_name, *var_val;
1115 for(i = 0; source[i] != NULL; i++) {
1116 var_name = xstrdup(source[i]);
1117 if ((var_val = strstr(var_name, "=")) == NULL) {
1123 debug3("Copy environment: %s=%s", var_name, var_val);
1124 child_set_env(env, envsize, var_name, var_val);
1131 do_setup_env(Session *s, const char *shell)
1136 struct passwd *pw = s->pw;
1137 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1140 extern char **environ;
1144 /* Initialize the environment. */
1146 env = xcalloc(envsize, sizeof(char *));
1151 * The Windows environment contains some setting which are
1152 * important for a running system. They must not be dropped.
1157 p = fetch_windows_environment();
1158 copy_environment(p, &env, &envsize);
1159 free_windows_environment(p);
1164 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1167 /* Allow any GSSAPI methods that we've used to alter
1168 * the childs environment as they see fit
1170 ssh_gssapi_do_child(&env, &envsize);
1173 if (!options.use_login) {
1174 /* Set basic environment. */
1175 for (i = 0; i < s->num_env; i++)
1176 child_set_env(&env, &envsize, s->env[i].name,
1179 child_set_env(&env, &envsize, "USER", pw->pw_name);
1180 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1182 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1184 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1185 snprintf(buf, sizeof buf, "%.200s/%.50s",
1186 _PATH_MAILDIR, pw->pw_name);
1187 child_set_env(&env, &envsize, "MAIL", buf);
1188 #ifdef HAVE_LOGIN_CAP
1189 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1190 child_set_env(&env, &envsize, "TERM", "su");
1192 environ = xmalloc(sizeof(char *));
1194 (void) setusercontext(lc, pw, pw->pw_uid,
1195 LOGIN_SETENV|LOGIN_SETPATH);
1196 copy_environment(environ, &env, &envsize);
1197 for (var = environ; *var != NULL; ++var)
1201 #else /* HAVE_LOGIN_CAP */
1202 # ifndef HAVE_CYGWIN
1204 * There's no standard path on Windows. The path contains
1205 * important components pointing to the system directories,
1206 * needed for loading shared libraries. So the path better
1207 * remains intact here.
1209 # ifdef HAVE_ETC_DEFAULT_LOGIN
1210 read_etc_default_login(&env, &envsize, pw->pw_uid);
1211 path = child_get_env(env, "PATH");
1212 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1213 if (path == NULL || *path == '\0') {
1214 child_set_env(&env, &envsize, "PATH",
1215 s->pw->pw_uid == 0 ?
1216 SUPERUSER_PATH : _PATH_STDPATH);
1218 # endif /* HAVE_CYGWIN */
1219 #endif /* HAVE_LOGIN_CAP */
1221 /* Normal systems set SHELL by default. */
1222 child_set_env(&env, &envsize, "SHELL", shell);
1225 /* Set custom environment options from RSA authentication. */
1226 if (!options.use_login) {
1227 while (custom_environment) {
1228 struct envstring *ce = custom_environment;
1231 for (i = 0; str[i] != '=' && str[i]; i++)
1233 if (str[i] == '=') {
1235 child_set_env(&env, &envsize, str, str + i + 1);
1237 custom_environment = ce->next;
1243 /* SSH_CLIENT deprecated */
1244 snprintf(buf, sizeof buf, "%.50s %d %d",
1245 get_remote_ipaddr(), get_remote_port(), get_local_port());
1246 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1248 laddr = get_local_ipaddr(packet_get_connection_in());
1249 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1250 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port());
1252 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1255 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1257 child_set_env(&env, &envsize, "TERM", s->term);
1259 child_set_env(&env, &envsize, "DISPLAY", s->display);
1260 if (original_command)
1261 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1265 if (cray_tmpdir[0] != '\0')
1266 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1267 #endif /* _UNICOS */
1270 * Since we clear KRB5CCNAME at startup, if it's set now then it
1271 * must have been set by a native authentication method (eg AIX or
1272 * SIA), so copy it to the child.
1277 if ((cp = getenv("KRB5CCNAME")) != NULL)
1278 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1285 if ((cp = getenv("AUTHSTATE")) != NULL)
1286 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1287 read_environment_file(&env, &envsize, "/etc/environment");
1291 if (s->authctxt->krb5_ccname)
1292 child_set_env(&env, &envsize, "KRB5CCNAME",
1293 s->authctxt->krb5_ccname);
1297 * Pull in any environment variables that may have
1300 if (options.use_pam) {
1303 p = fetch_pam_child_environment();
1304 copy_environment(p, &env, &envsize);
1305 free_pam_environment(p);
1307 p = fetch_pam_environment();
1308 copy_environment(p, &env, &envsize);
1309 free_pam_environment(p);
1311 #endif /* USE_PAM */
1313 if (auth_sock_name != NULL)
1314 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1317 /* read $HOME/.ssh/environment. */
1318 if (options.permit_user_env && !options.use_login) {
1319 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1320 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1321 read_environment_file(&env, &envsize, buf);
1324 /* dump the environment */
1325 fprintf(stderr, "Environment:\n");
1326 for (i = 0; env[i]; i++)
1327 fprintf(stderr, " %.200s\n", env[i]);
1333 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1334 * first in this order).
1337 do_rc_files(Session *s, const char *shell)
1345 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1347 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1348 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1349 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) {
1350 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1351 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1353 fprintf(stderr, "Running %s\n", cmd);
1354 f = popen(cmd, "w");
1357 fprintf(f, "%s %s\n", s->auth_proto,
1361 fprintf(stderr, "Could not run %s\n",
1363 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1365 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1366 _PATH_SSH_SYSTEM_RC);
1367 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1370 fprintf(f, "%s %s\n", s->auth_proto,
1374 fprintf(stderr, "Could not run %s\n",
1375 _PATH_SSH_SYSTEM_RC);
1376 } else if (do_xauth && options.xauth_location != NULL) {
1377 /* Add authority data to .Xauthority if appropriate. */
1380 "Running %.500s remove %.100s\n",
1381 options.xauth_location, s->auth_display);
1383 "%.500s add %.100s %.100s %.100s\n",
1384 options.xauth_location, s->auth_display,
1385 s->auth_proto, s->auth_data);
1387 snprintf(cmd, sizeof cmd, "%s -q -",
1388 options.xauth_location);
1389 f = popen(cmd, "w");
1391 fprintf(f, "remove %s\n",
1393 fprintf(f, "add %s %s %s\n",
1394 s->auth_display, s->auth_proto,
1398 fprintf(stderr, "Could not run %s\n",
1405 do_nologin(struct passwd *pw)
1408 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1411 #ifdef HAVE_LOGIN_CAP
1412 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1414 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1416 if (pw->pw_uid == 0)
1420 if (stat(nl, &sb) == -1) {
1426 /* /etc/nologin exists. Print its contents if we can and exit. */
1427 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1428 if ((f = fopen(nl, "r")) != NULL) {
1429 while (fgets(buf, sizeof(buf), f))
1437 * Chroot into a directory after checking it for safety: all path components
1438 * must be root-owned directories with strict permissions.
1441 safely_chroot(const char *path, uid_t uid)
1444 char component[MAXPATHLEN];
1448 fatal("chroot path does not begin at root");
1449 if (strlen(path) >= sizeof(component))
1450 fatal("chroot path too long");
1453 * Descend the path, checking that each component is a
1454 * root-owned directory with strict permissions.
1456 for (cp = path; cp != NULL;) {
1457 if ((cp = strchr(cp, '/')) == NULL)
1458 strlcpy(component, path, sizeof(component));
1461 memcpy(component, path, cp - path);
1462 component[cp - path] = '\0';
1465 debug3("%s: checking '%s'", __func__, component);
1467 if (stat(component, &st) != 0)
1468 fatal("%s: stat(\"%s\"): %s", __func__,
1469 component, strerror(errno));
1470 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1471 fatal("bad ownership or modes for chroot "
1472 "directory %s\"%s\"",
1473 cp == NULL ? "" : "component ", component);
1474 if (!S_ISDIR(st.st_mode))
1475 fatal("chroot path %s\"%s\" is not a directory",
1476 cp == NULL ? "" : "component ", component);
1480 if (chdir(path) == -1)
1481 fatal("Unable to chdir to chroot path \"%s\": "
1482 "%s", path, strerror(errno));
1483 if (chroot(path) == -1)
1484 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1485 if (chdir("/") == -1)
1486 fatal("%s: chdir(/) after chroot: %s",
1487 __func__, strerror(errno));
1488 verbose("Changed root directory to \"%s\"", path);
1491 /* Set login name, uid, gid, and groups. */
1493 do_setusercontext(struct passwd *pw)
1495 char *chroot_path, *tmp;
1497 platform_setusercontext(pw);
1499 if (platform_privileged_uidswap()) {
1500 #ifdef HAVE_LOGIN_CAP
1501 if (setusercontext(lc, pw, pw->pw_uid,
1502 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1503 perror("unable to set user context");
1507 if (setlogin(pw->pw_name) < 0)
1508 error("setlogin failed: %s", strerror(errno));
1509 if (setgid(pw->pw_gid) < 0) {
1513 /* Initialize the group list. */
1514 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1515 perror("initgroups");
1521 platform_setusercontext_post_groups(pw);
1523 if (options.chroot_directory != NULL &&
1524 strcasecmp(options.chroot_directory, "none") != 0) {
1525 tmp = tilde_expand_filename(options.chroot_directory,
1527 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1528 "u", pw->pw_name, (char *)NULL);
1529 safely_chroot(chroot_path, pw->pw_uid);
1534 #ifdef HAVE_LOGIN_CAP
1535 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1536 perror("unable to set user context (setuser)");
1540 * FreeBSD's setusercontext() will not apply the user's
1541 * own umask setting unless running with the user's UID.
1543 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK);
1545 /* Permanently switch to the desired uid. */
1546 permanently_set_uid(pw);
1550 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1551 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1555 do_pwchange(Session *s)
1558 fprintf(stderr, "WARNING: Your password has expired.\n");
1559 if (s->ttyfd != -1) {
1561 "You must change your password now and login again!\n");
1565 #ifdef PASSWD_NEEDS_USERNAME
1566 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1569 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1574 "Password change required but no TTY available.\n");
1580 launch_login(struct passwd *pw, const char *hostname)
1582 /* Launch login(1). */
1584 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1585 #ifdef xxxLOGIN_NEEDS_TERM
1586 (s->term ? s->term : "unknown"),
1587 #endif /* LOGIN_NEEDS_TERM */
1588 #ifdef LOGIN_NO_ENDOPT
1589 "-p", "-f", pw->pw_name, (char *)NULL);
1591 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1594 /* Login couldn't be executed, die. */
1601 child_close_fds(void)
1603 if (packet_get_connection_in() == packet_get_connection_out())
1604 close(packet_get_connection_in());
1606 close(packet_get_connection_in());
1607 close(packet_get_connection_out());
1610 * Close all descriptors related to channels. They will still remain
1611 * open in the parent.
1613 /* XXX better use close-on-exec? -markus */
1614 channel_close_all();
1617 * Close any extra file descriptors. Note that there may still be
1618 * descriptors left by system functions. They will be closed later.
1623 * Close any extra open file descriptors so that we don't have them
1624 * hanging around in clients. Note that we want to do this after
1625 * initgroups, because at least on Solaris 2.3 it leaves file
1628 closefrom(STDERR_FILENO + 1);
1632 * Performs common processing for the child, such as setting up the
1633 * environment, closing extra file descriptors, setting the user and group
1634 * ids, and executing the command or shell.
1638 do_child(Session *s, const char *command)
1640 extern char **environ;
1642 char *argv[ARGV_MAX];
1643 const char *shell, *shell0, *hostname = NULL;
1644 struct passwd *pw = s->pw;
1647 /* remove hostkey from the child's memory */
1648 destroy_sensitive_data();
1650 /* Force a password change */
1651 if (s->authctxt->force_pwchange) {
1652 do_setusercontext(pw);
1658 /* login(1) is only called if we execute the login shell */
1659 if (options.use_login && command != NULL)
1660 options.use_login = 0;
1663 cray_setup(pw->pw_uid, pw->pw_name, command);
1664 #endif /* _UNICOS */
1667 * Login(1) does this as well, and it needs uid 0 for the "-h"
1668 * switch, so we let login(1) to this for us.
1670 if (!options.use_login) {
1672 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1673 if (!check_quietlogin(s, command))
1675 #else /* HAVE_OSF_SIA */
1676 /* When PAM is enabled we rely on it to do the nologin check */
1677 if (!options.use_pam)
1679 do_setusercontext(pw);
1681 * PAM session modules in do_setusercontext may have
1682 * generated messages, so if this in an interactive
1683 * login then display them too.
1685 if (!check_quietlogin(s, command))
1687 #endif /* HAVE_OSF_SIA */
1691 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1692 debug3("PAM session not opened, exiting");
1699 * Get the shell from the password data. An empty shell field is
1700 * legal, and means /bin/sh.
1702 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1705 * Make sure $SHELL points to the shell from the password file,
1706 * even if shell is overridden from login.conf
1708 env = do_setup_env(s, shell);
1710 #ifdef HAVE_LOGIN_CAP
1711 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1714 /* we have to stash the hostname before we close our socket. */
1715 if (options.use_login)
1716 hostname = get_remote_name_or_ip(utmp_len,
1719 * Close the connection descriptors; note that this is the child, and
1720 * the server will still have the socket open, and it is important
1721 * that we do not shutdown it. Note that the descriptors cannot be
1722 * closed before building the environment, as we call
1723 * get_remote_ipaddr there.
1728 * Must take new environment into use so that .ssh/rc,
1729 * /etc/ssh/sshrc and xauth are run in the proper environment.
1733 #if defined(KRB5) && defined(USE_AFS)
1735 * At this point, we check to see if AFS is active and if we have
1736 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1737 * if we can (and need to) extend the ticket into an AFS token. If
1738 * we don't do this, we run into potential problems if the user's
1739 * home directory is in AFS and it's not world-readable.
1742 if (options.kerberos_get_afs_token && k_hasafs() &&
1743 (s->authctxt->krb5_ctx != NULL)) {
1746 debug("Getting AFS token");
1750 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1751 krb5_afslog(s->authctxt->krb5_ctx,
1752 s->authctxt->krb5_fwd_ccache, cell, NULL);
1754 krb5_afslog_home(s->authctxt->krb5_ctx,
1755 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1759 /* Change current directory to the user's home directory. */
1760 if (chdir(pw->pw_dir) < 0) {
1761 /* Suppress missing homedir warning for chroot case */
1762 #ifdef HAVE_LOGIN_CAP
1763 r = login_getcapbool(lc, "requirehome", 0);
1765 if (r || options.chroot_directory == NULL ||
1766 strcasecmp(options.chroot_directory, "none") == 0)
1767 fprintf(stderr, "Could not chdir to home "
1768 "directory %s: %s\n", pw->pw_dir,
1774 closefrom(STDERR_FILENO + 1);
1776 if (!options.use_login)
1777 do_rc_files(s, shell);
1779 /* restore SIGPIPE for child */
1780 signal(SIGPIPE, SIG_DFL);
1782 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1783 printf("This service allows sftp connections only.\n");
1786 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1787 extern int optind, optreset;
1791 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1792 args = xstrdup(command ? command : "sftp-server");
1793 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1794 if (i < ARGV_MAX - 1)
1797 optind = optreset = 1;
1798 __progname = argv[0];
1800 ssh_selinux_change_context("sftpd_t");
1802 exit(sftp_server_main(i, argv, s->pw));
1807 if (options.use_login) {
1808 launch_login(pw, hostname);
1812 /* Get the last component of the shell name. */
1813 if ((shell0 = strrchr(shell, '/')) != NULL)
1819 * If we have no command, execute the shell. In this case, the shell
1820 * name to be passed in argv[0] is preceded by '-' to indicate that
1821 * this is a login shell.
1826 /* Start the shell. Set initial character to '-'. */
1829 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1830 >= sizeof(argv0) - 1) {
1836 /* Execute the shell. */
1839 execve(shell, argv, env);
1841 /* Executing the shell failed. */
1846 * Execute the command using the user's shell. This uses the -c
1847 * option to execute the command.
1849 argv[0] = (char *) shell0;
1851 argv[2] = (char *) command;
1853 execve(shell, argv, env);
1859 session_unused(int id)
1861 debug3("%s: session id %d unused", __func__, id);
1862 if (id >= options.max_sessions ||
1863 id >= sessions_nalloc) {
1864 fatal("%s: insane session id %d (max %d nalloc %d)",
1865 __func__, id, options.max_sessions, sessions_nalloc);
1867 bzero(&sessions[id], sizeof(*sessions));
1868 sessions[id].self = id;
1869 sessions[id].used = 0;
1870 sessions[id].chanid = -1;
1871 sessions[id].ptyfd = -1;
1872 sessions[id].ttyfd = -1;
1873 sessions[id].ptymaster = -1;
1874 sessions[id].x11_chanids = NULL;
1875 sessions[id].next_unused = sessions_first_unused;
1876 sessions_first_unused = id;
1884 if (sessions_first_unused == -1) {
1885 if (sessions_nalloc >= options.max_sessions)
1887 debug2("%s: allocate (allocated %d max %d)",
1888 __func__, sessions_nalloc, options.max_sessions);
1889 tmp = xrealloc(sessions, sessions_nalloc + 1,
1892 error("%s: cannot allocate %d sessions",
1893 __func__, sessions_nalloc + 1);
1897 session_unused(sessions_nalloc++);
1900 if (sessions_first_unused >= sessions_nalloc ||
1901 sessions_first_unused < 0) {
1902 fatal("%s: insane first_unused %d max %d nalloc %d",
1903 __func__, sessions_first_unused, options.max_sessions,
1907 s = &sessions[sessions_first_unused];
1909 fatal("%s: session %d already used",
1910 __func__, sessions_first_unused);
1912 sessions_first_unused = s->next_unused;
1914 s->next_unused = -1;
1915 debug("session_new: session %d", s->self);
1924 for (i = 0; i < sessions_nalloc; i++) {
1925 Session *s = &sessions[i];
1927 debug("dump: used %d next_unused %d session %d %p "
1928 "channel %d pid %ld",
1939 session_open(Authctxt *authctxt, int chanid)
1941 Session *s = session_new();
1942 debug("session_open: channel %d", chanid);
1944 error("no more sessions");
1947 s->authctxt = authctxt;
1948 s->pw = authctxt->pw;
1949 if (s->pw == NULL || !authctxt->valid)
1950 fatal("no user for session %d", s->self);
1951 debug("session_open: session %d: link with channel %d", s->self, chanid);
1957 session_by_tty(char *tty)
1960 for (i = 0; i < sessions_nalloc; i++) {
1961 Session *s = &sessions[i];
1962 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1963 debug("session_by_tty: session %d tty %s", i, tty);
1967 debug("session_by_tty: unknown tty %.100s", tty);
1973 session_by_channel(int id)
1976 for (i = 0; i < sessions_nalloc; i++) {
1977 Session *s = &sessions[i];
1978 if (s->used && s->chanid == id) {
1979 debug("session_by_channel: session %d channel %d",
1984 debug("session_by_channel: unknown channel %d", id);
1990 session_by_x11_channel(int id)
1994 for (i = 0; i < sessions_nalloc; i++) {
1995 Session *s = &sessions[i];
1997 if (s->x11_chanids == NULL || !s->used)
1999 for (j = 0; s->x11_chanids[j] != -1; j++) {
2000 if (s->x11_chanids[j] == id) {
2001 debug("session_by_x11_channel: session %d "
2002 "channel %d", s->self, id);
2007 debug("session_by_x11_channel: unknown channel %d", id);
2013 session_by_pid(pid_t pid)
2016 debug("session_by_pid: pid %ld", (long)pid);
2017 for (i = 0; i < sessions_nalloc; i++) {
2018 Session *s = &sessions[i];
2019 if (s->used && s->pid == pid)
2022 error("session_by_pid: unknown pid %ld", (long)pid);
2028 session_window_change_req(Session *s)
2030 s->col = packet_get_int();
2031 s->row = packet_get_int();
2032 s->xpixel = packet_get_int();
2033 s->ypixel = packet_get_int();
2035 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2040 session_pty_req(Session *s)
2046 debug("Allocating a pty not permitted for this authentication.");
2049 if (s->ttyfd != -1) {
2050 packet_disconnect("Protocol error: you already have a pty.");
2054 s->term = packet_get_string(&len);
2057 s->col = packet_get_int();
2058 s->row = packet_get_int();
2060 s->row = packet_get_int();
2061 s->col = packet_get_int();
2063 s->xpixel = packet_get_int();
2064 s->ypixel = packet_get_int();
2066 if (strcmp(s->term, "") == 0) {
2071 /* Allocate a pty and open it. */
2072 debug("Allocating pty.");
2073 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2080 error("session_pty_req: session %d alloc failed", s->self);
2083 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2085 /* for SSH1 the tty modes length is not given */
2087 n_bytes = packet_remaining();
2088 tty_parse_modes(s->ttyfd, &n_bytes);
2091 pty_setowner(s->pw, s->tty);
2093 /* Set window size from the packet. */
2094 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2097 session_proctitle(s);
2102 session_subsystem_req(Session *s)
2107 char *prog, *cmd, *subsys = packet_get_string(&len);
2111 logit("subsystem request for %.100s by user %s", subsys,
2114 for (i = 0; i < options.num_subsystems; i++) {
2115 if (strcmp(subsys, options.subsystem_name[i]) == 0) {
2116 prog = options.subsystem_command[i];
2117 cmd = options.subsystem_args[i];
2118 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2119 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2120 debug("subsystem: %s", prog);
2122 if (stat(prog, &st) < 0)
2123 debug("subsystem: cannot stat %s: %s",
2124 prog, strerror(errno));
2125 s->is_subsystem = SUBSYSTEM_EXT;
2126 debug("subsystem: exec() %s", cmd);
2128 success = do_exec(s, cmd) == 0;
2134 logit("subsystem request for %.100s failed, subsystem not found",
2142 session_x11_req(Session *s)
2146 if (s->auth_proto != NULL || s->auth_data != NULL) {
2147 error("session_x11_req: session %d: "
2148 "x11 forwarding already active", s->self);
2151 s->single_connection = packet_get_char();
2152 s->auth_proto = packet_get_string(NULL);
2153 s->auth_data = packet_get_string(NULL);
2154 s->screen = packet_get_int();
2157 success = session_setup_x11fwd(s);
2159 xfree(s->auth_proto);
2160 xfree(s->auth_data);
2161 s->auth_proto = NULL;
2162 s->auth_data = NULL;
2168 session_shell_req(Session *s)
2171 return do_exec(s, NULL) == 0;
2175 session_exec_req(Session *s)
2179 char *command = packet_get_string(&len);
2181 success = do_exec(s, command) == 0;
2187 session_break_req(Session *s)
2190 packet_get_int(); /* ignored */
2193 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2199 session_env_req(Session *s)
2202 u_int name_len, val_len, i;
2204 name = packet_get_string(&name_len);
2205 val = packet_get_string(&val_len);
2208 /* Don't set too many environment variables */
2209 if (s->num_env > 128) {
2210 debug2("Ignoring env request %s: too many env vars", name);
2214 for (i = 0; i < options.num_accept_env; i++) {
2215 if (match_pattern(name, options.accept_env[i])) {
2216 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2217 s->env = xrealloc(s->env, s->num_env + 1,
2219 s->env[s->num_env].name = name;
2220 s->env[s->num_env].val = val;
2225 debug2("Ignoring env request %s: disallowed name", name);
2234 session_auth_agent_req(Session *s)
2236 static int called = 0;
2238 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2239 debug("session_auth_agent_req: no_agent_forwarding_flag");
2246 return auth_input_request_forwarding(s->pw);
2251 session_input_channel_req(Channel *c, const char *rtype)
2256 if ((s = session_by_channel(c->self)) == NULL) {
2257 logit("session_input_channel_req: no session %d req %.100s",
2261 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2264 * a session is in LARVAL state until a shell, a command
2265 * or a subsystem is executed
2267 if (c->type == SSH_CHANNEL_LARVAL) {
2268 if (strcmp(rtype, "shell") == 0) {
2269 success = session_shell_req(s);
2270 } else if (strcmp(rtype, "exec") == 0) {
2271 success = session_exec_req(s);
2272 } else if (strcmp(rtype, "pty-req") == 0) {
2273 success = session_pty_req(s);
2274 } else if (strcmp(rtype, "x11-req") == 0) {
2275 success = session_x11_req(s);
2276 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2277 success = session_auth_agent_req(s);
2278 } else if (strcmp(rtype, "subsystem") == 0) {
2279 success = session_subsystem_req(s);
2280 } else if (strcmp(rtype, "env") == 0) {
2281 success = session_env_req(s);
2284 if (strcmp(rtype, "window-change") == 0) {
2285 success = session_window_change_req(s);
2286 } else if (strcmp(rtype, "break") == 0) {
2287 success = session_break_req(s);
2294 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2298 fatal("session_set_fds: called for proto != 2.0");
2300 * now that have a child and a pipe to the child,
2301 * we can activate our channel and register the fd's
2303 if (s->chanid == -1)
2304 fatal("no channel for session %d", s->self);
2305 if (options.hpn_disabled)
2306 channel_set_fds(s->chanid, fdout, fdin, fderr,
2307 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2308 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2310 channel_set_fds(s->chanid, fdout, fdin, fderr,
2311 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2312 1, is_tty, options.hpn_buffer_size);
2316 * Function to perform pty cleanup. Also called if we get aborted abnormally
2317 * (e.g., due to a dropped connection).
2320 session_pty_cleanup2(Session *s)
2323 error("session_pty_cleanup: no session");
2329 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2331 /* Record that the user has logged out. */
2333 record_logout(s->pid, s->tty, s->pw->pw_name);
2335 /* Release the pseudo-tty. */
2337 pty_release(s->tty);
2340 * Close the server side of the socket pairs. We must do this after
2341 * the pty cleanup, so that another process doesn't get this pty
2342 * while we're still cleaning up.
2344 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2345 error("close(s->ptymaster/%d): %s",
2346 s->ptymaster, strerror(errno));
2348 /* unlink pty from session */
2353 session_pty_cleanup(Session *s)
2355 PRIVSEP(session_pty_cleanup2(s));
2361 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2376 return "SIG@openssh.com";
2380 session_close_x11(int id)
2384 if ((c = channel_by_id(id)) == NULL) {
2385 debug("session_close_x11: x11 channel %d missing", id);
2387 /* Detach X11 listener */
2388 debug("session_close_x11: detach x11 channel %d", id);
2389 channel_cancel_cleanup(id);
2390 if (c->ostate != CHAN_OUTPUT_CLOSED)
2396 session_close_single_x11(int id, void *arg)
2401 debug3("session_close_single_x11: channel %d", id);
2402 channel_cancel_cleanup(id);
2403 if ((s = session_by_x11_channel(id)) == NULL)
2404 fatal("session_close_single_x11: no x11 channel %d", id);
2405 for (i = 0; s->x11_chanids[i] != -1; i++) {
2406 debug("session_close_single_x11: session %d: "
2407 "closing channel %d", s->self, s->x11_chanids[i]);
2409 * The channel "id" is already closing, but make sure we
2410 * close all of its siblings.
2412 if (s->x11_chanids[i] != id)
2413 session_close_x11(s->x11_chanids[i]);
2415 xfree(s->x11_chanids);
2416 s->x11_chanids = NULL;
2421 if (s->auth_proto) {
2422 xfree(s->auth_proto);
2423 s->auth_proto = NULL;
2426 xfree(s->auth_data);
2427 s->auth_data = NULL;
2429 if (s->auth_display) {
2430 xfree(s->auth_display);
2431 s->auth_display = NULL;
2436 session_exit_message(Session *s, int status)
2440 if ((c = channel_lookup(s->chanid)) == NULL)
2441 fatal("session_exit_message: session %d: no channel %d",
2442 s->self, s->chanid);
2443 debug("session_exit_message: session %d channel %d pid %ld",
2444 s->self, s->chanid, (long)s->pid);
2446 if (WIFEXITED(status)) {
2447 channel_request_start(s->chanid, "exit-status", 0);
2448 packet_put_int(WEXITSTATUS(status));
2450 } else if (WIFSIGNALED(status)) {
2451 channel_request_start(s->chanid, "exit-signal", 0);
2452 packet_put_cstring(sig2name(WTERMSIG(status)));
2454 packet_put_char(WCOREDUMP(status)? 1 : 0);
2455 #else /* WCOREDUMP */
2457 #endif /* WCOREDUMP */
2458 packet_put_cstring("");
2459 packet_put_cstring("");
2462 /* Some weird exit cause. Just exit. */
2463 packet_disconnect("wait returned status %04x.", status);
2466 /* disconnect channel */
2467 debug("session_exit_message: release channel %d", s->chanid);
2470 * Adjust cleanup callback attachment to send close messages when
2471 * the channel gets EOF. The session will be then be closed
2472 * by session_close_by_channel when the childs close their fds.
2474 channel_register_cleanup(c->self, session_close_by_channel, 1);
2477 * emulate a write failure with 'chan_write_failed', nobody will be
2478 * interested in data we write.
2479 * Note that we must not call 'chan_read_failed', since there could
2480 * be some more data waiting in the pipe.
2482 if (c->ostate != CHAN_OUTPUT_CLOSED)
2483 chan_write_failed(c);
2487 session_close(Session *s)
2491 debug("session_close: session %d pid %ld", s->self, (long)s->pid);
2493 session_pty_cleanup(s);
2499 xfree(s->x11_chanids);
2500 if (s->auth_display)
2501 xfree(s->auth_display);
2503 xfree(s->auth_data);
2505 xfree(s->auth_proto);
2506 if (s->env != NULL) {
2507 for (i = 0; i < s->num_env; i++) {
2508 xfree(s->env[i].name);
2509 xfree(s->env[i].val);
2513 session_proctitle(s);
2514 session_unused(s->self);
2518 session_close_by_pid(pid_t pid, int status)
2520 Session *s = session_by_pid(pid);
2522 debug("session_close_by_pid: no session for pid %ld",
2526 if (s->chanid != -1)
2527 session_exit_message(s, status);
2529 session_pty_cleanup(s);
2534 * this is called when a channel dies before
2535 * the session 'child' itself dies
2538 session_close_by_channel(int id, void *arg)
2540 Session *s = session_by_channel(id);
2544 debug("session_close_by_channel: no session for id %d", id);
2547 debug("session_close_by_channel: channel %d child %ld",
2550 debug("session_close_by_channel: channel %d: has child", id);
2552 * delay detach of session, but release pty, since
2553 * the fd's to the child are already closed
2556 session_pty_cleanup(s);
2559 /* detach by removing callback */
2560 channel_cancel_cleanup(s->chanid);
2562 /* Close any X11 listeners associated with this session */
2563 if (s->x11_chanids != NULL) {
2564 for (i = 0; s->x11_chanids[i] != -1; i++) {
2565 session_close_x11(s->x11_chanids[i]);
2566 s->x11_chanids[i] = -1;
2575 session_destroy_all(void (*closefunc)(Session *))
2578 for (i = 0; i < sessions_nalloc; i++) {
2579 Session *s = &sessions[i];
2581 if (closefunc != NULL)
2590 session_tty_list(void)
2592 static char buf[1024];
2597 for (i = 0; i < sessions_nalloc; i++) {
2598 Session *s = &sessions[i];
2599 if (s->used && s->ttyfd != -1) {
2601 if (strncmp(s->tty, "/dev/", 5) != 0) {
2602 cp = strrchr(s->tty, '/');
2603 cp = (cp == NULL) ? s->tty : cp + 1;
2608 strlcat(buf, ",", sizeof buf);
2609 strlcat(buf, cp, sizeof buf);
2613 strlcpy(buf, "notty", sizeof buf);
2618 session_proctitle(Session *s)
2621 error("no user for session %d", s->self);
2623 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2627 session_setup_x11fwd(Session *s)
2630 char display[512], auth_display[512];
2631 char hostname[MAXHOSTNAMELEN];
2634 if (no_x11_forwarding_flag) {
2635 packet_send_debug("X11 forwarding disabled in user configuration file.");
2638 if (!options.x11_forwarding) {
2639 debug("X11 forwarding disabled in server configuration file.");
2642 if (!options.xauth_location ||
2643 (stat(options.xauth_location, &st) == -1)) {
2644 packet_send_debug("No xauth program; cannot forward with spoofing.");
2647 if (options.use_login) {
2648 packet_send_debug("X11 forwarding disabled; "
2649 "not compatible with UseLogin=yes.");
2652 if (s->display != NULL) {
2653 debug("X11 display already set.");
2656 if (x11_create_display_inet(options.x11_display_offset,
2657 options.x11_use_localhost, s->single_connection,
2658 &s->display_number, &s->x11_chanids) == -1) {
2659 debug("x11_create_display_inet failed.");
2662 for (i = 0; s->x11_chanids[i] != -1; i++) {
2663 channel_register_cleanup(s->x11_chanids[i],
2664 session_close_single_x11, 0);
2667 /* Set up a suitable value for the DISPLAY variable. */
2668 if (gethostname(hostname, sizeof(hostname)) < 0)
2669 fatal("gethostname: %.100s", strerror(errno));
2671 * auth_display must be used as the displayname when the
2672 * authorization entry is added with xauth(1). This will be
2673 * different than the DISPLAY string for localhost displays.
2675 if (options.x11_use_localhost) {
2676 snprintf(display, sizeof display, "localhost:%u.%u",
2677 s->display_number, s->screen);
2678 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2679 s->display_number, s->screen);
2680 s->display = xstrdup(display);
2681 s->auth_display = xstrdup(auth_display);
2683 #ifdef IPADDR_IN_DISPLAY
2685 struct in_addr my_addr;
2687 he = gethostbyname(hostname);
2689 error("Can't get IP address for X11 DISPLAY.");
2690 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2693 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2694 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2695 s->display_number, s->screen);
2697 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2698 s->display_number, s->screen);
2700 s->display = xstrdup(display);
2701 s->auth_display = xstrdup(display);
2708 do_authenticated2(Authctxt *authctxt)
2710 server_loop2(authctxt);
2714 do_cleanup(Authctxt *authctxt)
2716 static int called = 0;
2718 debug("do_cleanup");
2720 /* no cleanup if we're in the child for login shell */
2724 /* avoid double cleanup */
2729 if (authctxt == NULL)
2733 if (options.use_pam) {
2735 sshpam_thread_cleanup();
2739 if (!authctxt->authenticated)
2743 if (options.kerberos_ticket_cleanup &&
2745 krb5_cleanup_proc(authctxt);
2749 if (compat20 && options.gss_cleanup_creds)
2750 ssh_gssapi_cleanup_creds();
2753 /* remove agent socket */
2754 auth_sock_cleanup_proc(authctxt->pw);
2757 * Cleanup ptys/utmp only if privsep is disabled,
2758 * or if running in monitor.
2760 if (!use_privsep || mm_is_monitor())
2761 session_destroy_all(session_pty_cleanup2);