1 /* $OpenBSD: session.c,v 1.282 2016/03/10 11:47:57 djm Exp $ */
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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>
67 #include "openbsd-compat/sys-queue.h"
86 #include "auth-options.h"
88 #include "pathnames.h"
93 #include "serverloop.h"
97 #include "monitor_wrap.h"
100 #if defined(KRB5) && defined(USE_AFS)
105 #include <selinux/selinux.h>
108 #define IS_INTERNAL_SFTP(c) \
109 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
110 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
111 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
112 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
116 Session *session_new(void);
117 void session_set_fds(Session *, int, int, int, int, int);
118 void session_pty_cleanup(Session *);
119 void session_proctitle(Session *);
120 int session_setup_x11fwd(Session *);
121 int do_exec_pty(Session *, const char *);
122 int do_exec_no_pty(Session *, const char *);
123 int do_exec(Session *, const char *);
124 void do_login(Session *, const char *);
125 #ifdef LOGIN_NEEDS_UTMPX
126 static void do_pre_login(Session *s);
128 void do_child(Session *, const char *);
130 int check_quietlogin(Session *, const char *);
132 static void do_authenticated1(Authctxt *);
133 static void do_authenticated2(Authctxt *);
135 static int session_pty_req(Session *);
138 extern ServerOptions options;
139 extern char *__progname;
140 extern int log_stderr;
141 extern int debug_flag;
142 extern u_int utmp_len;
143 extern int startup_pipe;
144 extern void destroy_sensitive_data(void);
145 extern Buffer loginmsg;
147 /* original command from peer. */
148 const char *original_command = NULL;
151 static int sessions_first_unused = -1;
152 static int sessions_nalloc = 0;
153 static Session *sessions = NULL;
155 #define SUBSYSTEM_NONE 0
156 #define SUBSYSTEM_EXT 1
157 #define SUBSYSTEM_INT_SFTP 2
158 #define SUBSYSTEM_INT_SFTP_ERROR 3
160 #ifdef HAVE_LOGIN_CAP
164 static int is_child = 0;
165 static int in_chroot = 0;
167 /* Name and directory of socket for authentication agent forwarding. */
168 static char *auth_sock_name = NULL;
169 static char *auth_sock_dir = NULL;
171 /* removes the agent forwarding socket */
174 auth_sock_cleanup_proc(struct passwd *pw)
176 if (auth_sock_name != NULL) {
177 temporarily_use_uid(pw);
178 unlink(auth_sock_name);
179 rmdir(auth_sock_dir);
180 auth_sock_name = NULL;
186 auth_input_request_forwarding(struct passwd * pw)
191 if (auth_sock_name != NULL) {
192 error("authentication forwarding requested twice.");
196 /* Temporarily drop privileged uid for mkdir/bind. */
197 temporarily_use_uid(pw);
199 /* Allocate a buffer for the socket name, and format the name. */
200 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX");
202 /* Create private directory for socket */
203 if (mkdtemp(auth_sock_dir) == NULL) {
204 packet_send_debug("Agent forwarding disabled: "
205 "mkdtemp() failed: %.100s", strerror(errno));
208 auth_sock_dir = NULL;
212 xasprintf(&auth_sock_name, "%s/agent.%ld",
213 auth_sock_dir, (long) getpid());
215 /* Start a Unix listener on auth_sock_name. */
216 sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0);
218 /* Restore the privileged uid. */
221 /* Check for socket/bind/listen failure. */
225 /* Allocate a channel for the authentication agent socket. */
226 nc = channel_new("auth socket",
227 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1,
228 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
229 0, "auth socket", 1);
230 nc->path = xstrdup(auth_sock_name);
234 free(auth_sock_name);
235 if (auth_sock_dir != NULL) {
236 rmdir(auth_sock_dir);
241 auth_sock_name = NULL;
242 auth_sock_dir = NULL;
247 display_loginmsg(void)
249 if (buffer_len(&loginmsg) > 0) {
250 buffer_append(&loginmsg, "\0", 1);
251 printf("%s", (char *)buffer_ptr(&loginmsg));
252 buffer_clear(&loginmsg);
257 do_authenticated(Authctxt *authctxt)
259 setproctitle("%s", authctxt->pw->pw_name);
261 /* setup the channel layer */
262 /* XXX - streamlocal? */
263 if (no_port_forwarding_flag ||
264 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
265 channel_disable_adm_local_opens();
267 channel_permit_all_opens();
272 do_authenticated2(authctxt);
274 do_authenticated1(authctxt);
276 do_cleanup(authctxt);
279 /* Check untrusted xauth strings for metacharacters */
281 xauth_valid_string(const char *s)
285 for (i = 0; s[i] != '\0'; i++) {
286 if (!isalnum((u_char)s[i]) &&
287 s[i] != '.' && s[i] != ':' && s[i] != '/' &&
288 s[i] != '-' && s[i] != '_')
295 * Prepares for an interactive session. This is called after the user has
296 * been successfully authenticated. During this message exchange, pseudo
297 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
298 * are requested, etc.
301 do_authenticated1(Authctxt *authctxt)
305 int success, type, screen_flag;
306 int enable_compression_after_reply = 0;
307 u_int proto_len, data_len, dlen, compression_level = 0;
311 error("no more sessions");
314 s->authctxt = authctxt;
315 s->pw = authctxt->pw;
318 * We stay in this loop until the client requests to execute a shell
324 /* Get a packet from the client. */
325 type = packet_read();
327 /* Process the packet. */
329 case SSH_CMSG_REQUEST_COMPRESSION:
330 compression_level = packet_get_int();
332 if (compression_level < 1 || compression_level > 9) {
333 packet_send_debug("Received invalid compression level %d.",
337 if (options.compression == COMP_NONE) {
338 debug2("compression disabled");
341 /* Enable compression after we have responded with SUCCESS. */
342 enable_compression_after_reply = 1;
346 case SSH_CMSG_REQUEST_PTY:
347 success = session_pty_req(s);
350 case SSH_CMSG_X11_REQUEST_FORWARDING:
351 s->auth_proto = packet_get_string(&proto_len);
352 s->auth_data = packet_get_string(&data_len);
354 screen_flag = packet_get_protocol_flags() &
355 SSH_PROTOFLAG_SCREEN_NUMBER;
356 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag);
358 if (packet_remaining() == 4) {
360 debug2("Buggy client: "
361 "X11 screen flag missing");
362 s->screen = packet_get_int();
367 if (xauth_valid_string(s->auth_proto) &&
368 xauth_valid_string(s->auth_data))
369 success = session_setup_x11fwd(s);
372 error("Invalid X11 forwarding data");
377 s->auth_proto = NULL;
382 case SSH_CMSG_AGENT_REQUEST_FORWARDING:
383 if (!options.allow_agent_forwarding ||
384 no_agent_forwarding_flag || compat13) {
385 debug("Authentication agent forwarding not permitted for this authentication.");
388 debug("Received authentication agent forwarding request.");
389 success = auth_input_request_forwarding(s->pw);
392 case SSH_CMSG_PORT_FORWARD_REQUEST:
393 if (no_port_forwarding_flag) {
394 debug("Port forwarding not permitted for this authentication.");
397 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) {
398 debug("Port forwarding not permitted.");
401 debug("Received TCP/IP port forwarding request.");
402 if (channel_input_port_forward_request(s->pw->pw_uid == 0,
403 &options.fwd_opts) < 0) {
404 debug("Port forwarding failed.");
410 case SSH_CMSG_MAX_PACKET_SIZE:
411 if (packet_set_maxsize(packet_get_int()) > 0)
415 case SSH_CMSG_EXEC_SHELL:
416 case SSH_CMSG_EXEC_CMD:
417 if (type == SSH_CMSG_EXEC_CMD) {
418 command = packet_get_string(&dlen);
419 debug("Exec command '%.500s'", command);
420 if (do_exec(s, command) != 0)
422 "command execution failed");
425 if (do_exec(s, NULL) != 0)
427 "shell execution failed");
435 * Any unknown messages in this phase are ignored,
436 * and a failure message is returned.
438 logit("Unknown packet type received after authentication: %d", type);
440 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE);
444 /* Enable compression now that we have replied if appropriate. */
445 if (enable_compression_after_reply) {
446 enable_compression_after_reply = 0;
447 packet_start_compression(compression_level);
454 * This is called to fork and execute a command when we have no tty. This
455 * will call do_child from the child, and server_loop from the parent after
456 * setting up file descriptors and such.
459 do_exec_no_pty(Session *s, const char *command)
464 int pin[2], pout[2], perr[2];
467 fatal("do_exec_no_pty: no session");
469 /* Allocate pipes for communicating with the program. */
471 error("%s: pipe in: %.100s", __func__, strerror(errno));
474 if (pipe(pout) < 0) {
475 error("%s: pipe out: %.100s", __func__, strerror(errno));
480 if (pipe(perr) < 0) {
481 error("%s: pipe err: %.100s", __func__,
490 int inout[2], err[2];
493 fatal("do_exec_no_pty: no session");
495 /* Uses socket pairs to communicate with the program. */
496 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
497 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
500 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
501 error("%s: socketpair #2: %.100s", __func__,
509 session_proctitle(s);
511 /* Fork the child. */
512 switch ((pid = fork())) {
514 error("%s: fork: %.100s", __func__, strerror(errno));
532 /* Child. Reinitialize the log since the pid has changed. */
533 log_init(__progname, options.log_level,
534 options.log_facility, log_stderr);
537 * Create a new session and process group since the 4.4BSD
538 * setlogin() affects the entire process group.
541 error("setsid failed: %.100s", strerror(errno));
545 * Redirect stdin. We close the parent side of the socket
546 * pair, and make the child side the standard input.
549 if (dup2(pin[0], 0) < 0)
550 perror("dup2 stdin");
553 /* Redirect stdout. */
555 if (dup2(pout[1], 1) < 0)
556 perror("dup2 stdout");
559 /* Redirect stderr. */
561 if (dup2(perr[1], 2) < 0)
562 perror("dup2 stderr");
566 * Redirect stdin, stdout, and stderr. Stdin and stdout will
567 * use the same socket, as some programs (particularly rdist)
568 * seem to depend on it.
572 if (dup2(inout[0], 0) < 0) /* stdin */
573 perror("dup2 stdin");
574 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
575 perror("dup2 stdout");
577 if (dup2(err[0], 2) < 0) /* stderr */
578 perror("dup2 stderr");
584 cray_init_job(s->pw); /* set up cray jid and tmpdir */
587 /* Do processing for the child (exec command etc). */
588 do_child(s, command);
595 signal(WJSIGNAL, cray_job_termination_handler);
598 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
602 /* Set interactive/non-interactive mode. */
603 packet_set_interactive(s->display != NULL,
604 options.ip_qos_interactive, options.ip_qos_bulk);
607 * Clear loginmsg, since it's the child's responsibility to display
608 * it to the user, otherwise multiple sessions may accumulate
609 * multiple copies of the login messages.
611 buffer_clear(&loginmsg);
614 /* We are the parent. Close the child sides of the pipes. */
620 session_set_fds(s, pin[1], pout[0], perr[0],
623 /* Enter the interactive session. */
624 server_loop(pid, pin[1], pout[0], perr[0]);
625 /* server_loop has closed pin[1], pout[0], and perr[0]. */
628 /* We are the parent. Close the child sides of the socket pairs. */
633 * Enter the interactive session. Note: server_loop must be able to
634 * handle the case that fdin and fdout are the same.
637 session_set_fds(s, inout[1], inout[1], err[1],
640 server_loop(pid, inout[1], inout[1], err[1]);
641 /* server_loop has closed inout[1] and err[1]. */
648 * This is called to fork and execute a command when we have a tty. This
649 * will call do_child from the child, and server_loop from the parent after
650 * setting up file descriptors, controlling tty, updating wtmp, utmp,
651 * lastlog, and other such operations.
654 do_exec_pty(Session *s, const char *command)
656 int fdout, ptyfd, ttyfd, ptymaster;
660 fatal("do_exec_pty: no session");
665 * Create another descriptor of the pty master side for use as the
666 * standard input. We could use the original descriptor, but this
667 * simplifies code in server_loop. The descriptor is bidirectional.
668 * Do this before forking (and cleanup in the child) so as to
669 * detect and gracefully fail out-of-fd conditions.
671 if ((fdout = dup(ptyfd)) < 0) {
672 error("%s: dup #1: %s", __func__, strerror(errno));
677 /* we keep a reference to the pty master */
678 if ((ptymaster = dup(ptyfd)) < 0) {
679 error("%s: dup #2: %s", __func__, strerror(errno));
686 /* Fork the child. */
687 switch ((pid = fork())) {
689 error("%s: fork: %.100s", __func__, strerror(errno));
701 /* Child. Reinitialize the log because the pid has changed. */
702 log_init(__progname, options.log_level,
703 options.log_facility, log_stderr);
704 /* Close the master side of the pseudo tty. */
707 /* Make the pseudo tty our controlling tty. */
708 pty_make_controlling_tty(&ttyfd, s->tty);
710 /* Redirect stdin/stdout/stderr from the pseudo tty. */
711 if (dup2(ttyfd, 0) < 0)
712 error("dup2 stdin: %s", strerror(errno));
713 if (dup2(ttyfd, 1) < 0)
714 error("dup2 stdout: %s", strerror(errno));
715 if (dup2(ttyfd, 2) < 0)
716 error("dup2 stderr: %s", strerror(errno));
718 /* Close the extra descriptor for the pseudo tty. */
721 /* record login, etc. similar to login(1) */
723 if (!(options.use_login && command == NULL)) {
725 cray_init_job(s->pw); /* set up cray jid and tmpdir */
727 do_login(s, command);
729 # ifdef LOGIN_NEEDS_UTMPX
735 * Do common processing for the child, such as execing
738 do_child(s, command);
745 signal(WJSIGNAL, cray_job_termination_handler);
748 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
753 /* Parent. Close the slave side of the pseudo tty. */
756 /* Enter interactive session. */
757 s->ptymaster = ptymaster;
758 packet_set_interactive(1,
759 options.ip_qos_interactive, options.ip_qos_bulk);
761 session_set_fds(s, ptyfd, fdout, -1, 1, 1);
763 server_loop(pid, ptyfd, fdout, -1);
764 /* server_loop _has_ closed ptyfd and fdout. */
769 #ifdef LOGIN_NEEDS_UTMPX
771 do_pre_login(Session *s)
773 struct ssh *ssh = active_state; /* XXX */
775 struct sockaddr_storage from;
776 pid_t pid = getpid();
779 * Get IP address of client. If the connection is not a socket, let
780 * the address be 0.0.0.0.
782 memset(&from, 0, sizeof(from));
783 fromlen = sizeof(from);
784 if (packet_connection_is_on_socket()) {
785 if (getpeername(packet_get_connection_in(),
786 (struct sockaddr *)&from, &fromlen) < 0) {
787 debug("getpeername: %.100s", strerror(errno));
792 record_utmp_only(pid, s->tty, s->pw->pw_name,
793 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns),
794 (struct sockaddr *)&from, fromlen);
799 * This is called to fork and execute a command. If another command is
800 * to be forced, execute that instead.
803 do_exec(Session *s, const char *command)
805 struct ssh *ssh = active_state; /* XXX */
807 const char *forced = NULL, *tty = NULL;
808 char session_type[1024];
810 if (options.adm_forced_command) {
811 original_command = command;
812 command = options.adm_forced_command;
814 } else if (forced_command) {
815 original_command = command;
816 command = forced_command;
817 forced = "(key-option)";
819 if (forced != NULL) {
820 if (IS_INTERNAL_SFTP(command)) {
821 s->is_subsystem = s->is_subsystem ?
822 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
823 } else if (s->is_subsystem)
824 s->is_subsystem = SUBSYSTEM_EXT;
825 snprintf(session_type, sizeof(session_type),
826 "forced-command %s '%.900s'", forced, command);
827 } else if (s->is_subsystem) {
828 snprintf(session_type, sizeof(session_type),
829 "subsystem '%.900s'", s->subsys);
830 } else if (command == NULL) {
831 snprintf(session_type, sizeof(session_type), "shell");
833 /* NB. we don't log unforced commands to preserve privacy */
834 snprintf(session_type, sizeof(session_type), "command");
837 if (s->ttyfd != -1) {
839 if (strncmp(tty, "/dev/", 5) == 0)
843 verbose("Starting session: %s%s%s for %s from %.200s port %d id %d",
845 tty == NULL ? "" : " on ",
846 tty == NULL ? "" : tty,
848 ssh_remote_ipaddr(ssh),
849 ssh_remote_port(ssh),
852 #ifdef SSH_AUDIT_EVENTS
854 PRIVSEP(audit_run_command(command));
855 else if (s->ttyfd == -1) {
856 char *shell = s->pw->pw_shell;
858 if (shell[0] == '\0') /* empty shell means /bin/sh */
860 PRIVSEP(audit_run_command(shell));
864 ret = do_exec_pty(s, command);
866 ret = do_exec_no_pty(s, command);
868 original_command = NULL;
871 * Clear loginmsg: it's the child's responsibility to display
872 * it to the user, otherwise multiple sessions may accumulate
873 * multiple copies of the login messages.
875 buffer_clear(&loginmsg);
880 /* administrative, login(1)-like work */
882 do_login(Session *s, const char *command)
884 struct ssh *ssh = active_state; /* XXX */
886 struct sockaddr_storage from;
887 struct passwd * pw = s->pw;
888 pid_t pid = getpid();
891 * Get IP address of client. If the connection is not a socket, let
892 * the address be 0.0.0.0.
894 memset(&from, 0, sizeof(from));
895 fromlen = sizeof(from);
896 if (packet_connection_is_on_socket()) {
897 if (getpeername(packet_get_connection_in(),
898 (struct sockaddr *)&from, &fromlen) < 0) {
899 debug("getpeername: %.100s", strerror(errno));
904 /* Record that there was a login on that tty from the remote host. */
906 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
907 session_get_remote_name_or_ip(ssh, utmp_len,
909 (struct sockaddr *)&from, fromlen);
913 * If password change is needed, do it now.
914 * This needs to occur before the ~/.hushlogin check.
916 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
919 s->authctxt->force_pwchange = 0;
920 /* XXX - signal [net] parent to enable forwardings */
924 if (check_quietlogin(s, command))
933 * Display the message of the day.
941 if (options.print_motd) {
942 #ifdef HAVE_LOGIN_CAP
943 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
946 f = fopen("/etc/motd", "r");
949 while (fgets(buf, sizeof(buf), f))
958 * Check for quiet login, either .hushlogin or command given.
961 check_quietlogin(Session *s, const char *command)
964 struct passwd *pw = s->pw;
967 /* Return 1 if .hushlogin exists or a command given. */
970 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
971 #ifdef HAVE_LOGIN_CAP
972 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
975 if (stat(buf, &st) >= 0)
982 * Sets the value of the given variable in the environment. If the variable
983 * already exists, its value is overridden.
986 child_set_env(char ***envp, u_int *envsizep, const char *name,
993 if (strchr(name, '=') != NULL) {
994 error("Invalid environment variable \"%.100s\"", name);
999 * If we're passed an uninitialized list, allocate a single null
1000 * entry before continuing.
1002 if (*envp == NULL && *envsizep == 0) {
1003 *envp = xmalloc(sizeof(char *));
1009 * Find the slot where the value should be stored. If the variable
1010 * already exists, we reuse the slot; otherwise we append a new slot
1011 * at the end of the array, expanding if necessary.
1014 namelen = strlen(name);
1015 for (i = 0; env[i]; i++)
1016 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
1019 /* Reuse the slot. */
1022 /* New variable. Expand if necessary. */
1023 envsize = *envsizep;
1024 if (i >= envsize - 1) {
1025 if (envsize >= 1000)
1026 fatal("child_set_env: too many env vars");
1028 env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
1029 *envsizep = envsize;
1031 /* Need to set the NULL pointer at end of array beyond the new slot. */
1035 /* Allocate space and format the variable in the appropriate slot. */
1036 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
1037 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
1041 * Reads environment variables from the given file and adds/overrides them
1042 * into the environment. If the file does not exist, this does nothing.
1043 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1044 * and assignments of the form name=value. No other forms are allowed.
1047 read_environment_file(char ***env, u_int *envsize,
1048 const char *filename)
1055 f = fopen(filename, "r");
1059 while (fgets(buf, sizeof(buf), f)) {
1060 if (++lineno > 1000)
1061 fatal("Too many lines in environment file %s", filename);
1062 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
1064 if (!*cp || *cp == '#' || *cp == '\n')
1067 cp[strcspn(cp, "\n")] = '\0';
1069 value = strchr(cp, '=');
1070 if (value == NULL) {
1071 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
1076 * Replace the equals sign by nul, and advance value to
1081 child_set_env(env, envsize, cp, value);
1086 #ifdef HAVE_ETC_DEFAULT_LOGIN
1088 * Return named variable from specified environment, or NULL if not present.
1091 child_get_env(char **env, const char *name)
1097 for (i=0; env[i] != NULL; i++)
1098 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
1099 return(env[i] + len + 1);
1104 * Read /etc/default/login.
1105 * We pick up the PATH (or SUPATH for root) and UMASK.
1108 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
1110 char **tmpenv = NULL, *var;
1111 u_int i, tmpenvsize = 0;
1115 * We don't want to copy the whole file to the child's environment,
1116 * so we use a temporary environment and copy the variables we're
1119 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login");
1125 var = child_get_env(tmpenv, "SUPATH");
1127 var = child_get_env(tmpenv, "PATH");
1129 child_set_env(env, envsize, "PATH", var);
1131 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
1132 if (sscanf(var, "%5lo", &mask) == 1)
1133 umask((mode_t)mask);
1135 for (i = 0; tmpenv[i] != NULL; i++)
1139 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1142 copy_environment(char **source, char ***env, u_int *envsize)
1144 char *var_name, *var_val;
1150 for(i = 0; source[i] != NULL; i++) {
1151 var_name = xstrdup(source[i]);
1152 if ((var_val = strstr(var_name, "=")) == NULL) {
1158 debug3("Copy environment: %s=%s", var_name, var_val);
1159 child_set_env(env, envsize, var_name, var_val);
1166 do_setup_env(Session *s, const char *shell)
1168 struct ssh *ssh = active_state; /* XXX */
1172 struct passwd *pw = s->pw;
1173 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1176 extern char **environ;
1180 /* Initialize the environment. */
1182 env = xcalloc(envsize, sizeof(char *));
1187 * The Windows environment contains some setting which are
1188 * important for a running system. They must not be dropped.
1193 p = fetch_windows_environment();
1194 copy_environment(p, &env, &envsize);
1195 free_windows_environment(p);
1200 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1203 /* Allow any GSSAPI methods that we've used to alter
1204 * the childs environment as they see fit
1206 ssh_gssapi_do_child(&env, &envsize);
1209 if (!options.use_login) {
1210 /* Set basic environment. */
1211 for (i = 0; i < s->num_env; i++)
1212 child_set_env(&env, &envsize, s->env[i].name,
1215 child_set_env(&env, &envsize, "USER", pw->pw_name);
1216 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1218 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1220 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1221 snprintf(buf, sizeof buf, "%.200s/%.50s",
1222 _PATH_MAILDIR, pw->pw_name);
1223 child_set_env(&env, &envsize, "MAIL", buf);
1224 #ifdef HAVE_LOGIN_CAP
1225 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1226 child_set_env(&env, &envsize, "TERM", "su");
1228 environ = xmalloc(sizeof(char *));
1230 (void) setusercontext(lc, pw, pw->pw_uid,
1231 LOGIN_SETENV|LOGIN_SETPATH);
1232 copy_environment(environ, &env, &envsize);
1233 for (var = environ; *var != NULL; ++var)
1237 #else /* HAVE_LOGIN_CAP */
1238 # ifndef HAVE_CYGWIN
1240 * There's no standard path on Windows. The path contains
1241 * important components pointing to the system directories,
1242 * needed for loading shared libraries. So the path better
1243 * remains intact here.
1245 # ifdef HAVE_ETC_DEFAULT_LOGIN
1246 read_etc_default_login(&env, &envsize, pw->pw_uid);
1247 path = child_get_env(env, "PATH");
1248 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1249 if (path == NULL || *path == '\0') {
1250 child_set_env(&env, &envsize, "PATH",
1251 s->pw->pw_uid == 0 ?
1252 SUPERUSER_PATH : _PATH_STDPATH);
1254 # endif /* HAVE_CYGWIN */
1255 #endif /* HAVE_LOGIN_CAP */
1257 /* Normal systems set SHELL by default. */
1258 child_set_env(&env, &envsize, "SHELL", shell);
1261 /* Set custom environment options from RSA authentication. */
1262 if (!options.use_login) {
1263 while (custom_environment) {
1264 struct envstring *ce = custom_environment;
1267 for (i = 0; str[i] != '=' && str[i]; i++)
1269 if (str[i] == '=') {
1271 child_set_env(&env, &envsize, str, str + i + 1);
1273 custom_environment = ce->next;
1279 /* SSH_CLIENT deprecated */
1280 snprintf(buf, sizeof buf, "%.50s %d %d",
1281 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1282 ssh_local_port(ssh));
1283 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1285 laddr = get_local_ipaddr(packet_get_connection_in());
1286 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1287 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1288 laddr, ssh_local_port(ssh));
1290 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1293 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1295 child_set_env(&env, &envsize, "TERM", s->term);
1297 child_set_env(&env, &envsize, "DISPLAY", s->display);
1298 if (original_command)
1299 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1303 if (cray_tmpdir[0] != '\0')
1304 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir);
1305 #endif /* _UNICOS */
1308 * Since we clear KRB5CCNAME at startup, if it's set now then it
1309 * must have been set by a native authentication method (eg AIX or
1310 * SIA), so copy it to the child.
1315 if ((cp = getenv("KRB5CCNAME")) != NULL)
1316 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1323 if ((cp = getenv("AUTHSTATE")) != NULL)
1324 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1325 read_environment_file(&env, &envsize, "/etc/environment");
1329 if (s->authctxt->krb5_ccname)
1330 child_set_env(&env, &envsize, "KRB5CCNAME",
1331 s->authctxt->krb5_ccname);
1335 * Pull in any environment variables that may have
1338 if (options.use_pam && !options.use_login) {
1341 p = fetch_pam_child_environment();
1342 copy_environment(p, &env, &envsize);
1343 free_pam_environment(p);
1345 p = fetch_pam_environment();
1346 copy_environment(p, &env, &envsize);
1347 free_pam_environment(p);
1349 #endif /* USE_PAM */
1351 if (auth_sock_name != NULL)
1352 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1355 /* read $HOME/.ssh/environment. */
1356 if (options.permit_user_env && !options.use_login) {
1357 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1358 strcmp(pw->pw_dir, "/") ? pw->pw_dir : "");
1359 read_environment_file(&env, &envsize, buf);
1362 /* dump the environment */
1363 fprintf(stderr, "Environment:\n");
1364 for (i = 0; env[i]; i++)
1365 fprintf(stderr, " %.200s\n", env[i]);
1371 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1372 * first in this order).
1375 do_rc_files(Session *s, const char *shell)
1383 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1385 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1386 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1387 !no_user_rc && options.permit_user_rc &&
1388 stat(_PATH_SSH_USER_RC, &st) >= 0) {
1389 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1390 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1392 fprintf(stderr, "Running %s\n", cmd);
1393 f = popen(cmd, "w");
1396 fprintf(f, "%s %s\n", s->auth_proto,
1400 fprintf(stderr, "Could not run %s\n",
1402 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1404 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1405 _PATH_SSH_SYSTEM_RC);
1406 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1409 fprintf(f, "%s %s\n", s->auth_proto,
1413 fprintf(stderr, "Could not run %s\n",
1414 _PATH_SSH_SYSTEM_RC);
1415 } else if (do_xauth && options.xauth_location != NULL) {
1416 /* Add authority data to .Xauthority if appropriate. */
1419 "Running %.500s remove %.100s\n",
1420 options.xauth_location, s->auth_display);
1422 "%.500s add %.100s %.100s %.100s\n",
1423 options.xauth_location, s->auth_display,
1424 s->auth_proto, s->auth_data);
1426 snprintf(cmd, sizeof cmd, "%s -q -",
1427 options.xauth_location);
1428 f = popen(cmd, "w");
1430 fprintf(f, "remove %s\n",
1432 fprintf(f, "add %s %s %s\n",
1433 s->auth_display, s->auth_proto,
1437 fprintf(stderr, "Could not run %s\n",
1444 do_nologin(struct passwd *pw)
1447 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1450 #ifdef HAVE_LOGIN_CAP
1451 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1453 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1455 if (pw->pw_uid == 0)
1459 if (stat(nl, &sb) == -1) {
1465 /* /etc/nologin exists. Print its contents if we can and exit. */
1466 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1467 if ((f = fopen(nl, "r")) != NULL) {
1468 while (fgets(buf, sizeof(buf), f))
1476 * Chroot into a directory after checking it for safety: all path components
1477 * must be root-owned directories with strict permissions.
1480 safely_chroot(const char *path, uid_t uid)
1483 char component[PATH_MAX];
1487 fatal("chroot path does not begin at root");
1488 if (strlen(path) >= sizeof(component))
1489 fatal("chroot path too long");
1492 * Descend the path, checking that each component is a
1493 * root-owned directory with strict permissions.
1495 for (cp = path; cp != NULL;) {
1496 if ((cp = strchr(cp, '/')) == NULL)
1497 strlcpy(component, path, sizeof(component));
1500 memcpy(component, path, cp - path);
1501 component[cp - path] = '\0';
1504 debug3("%s: checking '%s'", __func__, component);
1506 if (stat(component, &st) != 0)
1507 fatal("%s: stat(\"%s\"): %s", __func__,
1508 component, strerror(errno));
1509 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1510 fatal("bad ownership or modes for chroot "
1511 "directory %s\"%s\"",
1512 cp == NULL ? "" : "component ", component);
1513 if (!S_ISDIR(st.st_mode))
1514 fatal("chroot path %s\"%s\" is not a directory",
1515 cp == NULL ? "" : "component ", component);
1519 if (chdir(path) == -1)
1520 fatal("Unable to chdir to chroot path \"%s\": "
1521 "%s", path, strerror(errno));
1522 if (chroot(path) == -1)
1523 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1524 if (chdir("/") == -1)
1525 fatal("%s: chdir(/) after chroot: %s",
1526 __func__, strerror(errno));
1527 verbose("Changed root directory to \"%s\"", path);
1530 /* Set login name, uid, gid, and groups. */
1532 do_setusercontext(struct passwd *pw)
1534 char *chroot_path, *tmp;
1536 platform_setusercontext(pw);
1538 if (platform_privileged_uidswap()) {
1539 #ifdef HAVE_LOGIN_CAP
1540 if (setusercontext(lc, pw, pw->pw_uid,
1541 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1542 perror("unable to set user context");
1546 if (setlogin(pw->pw_name) < 0)
1547 error("setlogin failed: %s", strerror(errno));
1548 if (setgid(pw->pw_gid) < 0) {
1552 /* Initialize the group list. */
1553 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1554 perror("initgroups");
1560 platform_setusercontext_post_groups(pw);
1562 if (!in_chroot && options.chroot_directory != NULL &&
1563 strcasecmp(options.chroot_directory, "none") != 0) {
1564 tmp = tilde_expand_filename(options.chroot_directory,
1566 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1567 "u", pw->pw_name, (char *)NULL);
1568 safely_chroot(chroot_path, pw->pw_uid);
1571 /* Make sure we don't attempt to chroot again */
1572 free(options.chroot_directory);
1573 options.chroot_directory = NULL;
1577 #ifdef HAVE_LOGIN_CAP
1578 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1579 perror("unable to set user context (setuser)");
1583 * FreeBSD's setusercontext() will not apply the user's
1584 * own umask setting unless running with the user's UID.
1586 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK);
1590 * In a chroot environment, the set_id() will always fail;
1591 * typically because of the lack of necessary authentication
1592 * services and runtime such as ./usr/lib/libiaf.so,
1593 * ./usr/lib/libpam.so.1, and ./etc/passwd We skip it in the
1594 * internal sftp chroot case. We'll lose auditing and ACLs but
1595 * permanently_set_uid will take care of the rest.
1597 if (!in_chroot && set_id(pw->pw_name) != 0)
1598 fatal("set_id(%s) Failed", pw->pw_name);
1599 # endif /* USE_LIBIAF */
1600 /* Permanently switch to the desired uid. */
1601 permanently_set_uid(pw);
1603 } else if (options.chroot_directory != NULL &&
1604 strcasecmp(options.chroot_directory, "none") != 0) {
1605 fatal("server lacks privileges to chroot to ChrootDirectory");
1608 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1609 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1613 do_pwchange(Session *s)
1616 fprintf(stderr, "WARNING: Your password has expired.\n");
1617 if (s->ttyfd != -1) {
1619 "You must change your password now and login again!\n");
1623 #ifdef PASSWD_NEEDS_USERNAME
1624 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1627 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1632 "Password change required but no TTY available.\n");
1638 launch_login(struct passwd *pw, const char *hostname)
1640 /* Launch login(1). */
1642 execl(LOGIN_PROGRAM, "login", "-h", hostname,
1643 #ifdef xxxLOGIN_NEEDS_TERM
1644 (s->term ? s->term : "unknown"),
1645 #endif /* LOGIN_NEEDS_TERM */
1646 #ifdef LOGIN_NO_ENDOPT
1647 "-p", "-f", pw->pw_name, (char *)NULL);
1649 "-p", "-f", "--", pw->pw_name, (char *)NULL);
1652 /* Login couldn't be executed, die. */
1659 child_close_fds(void)
1661 extern int auth_sock;
1663 if (auth_sock != -1) {
1668 if (packet_get_connection_in() == packet_get_connection_out())
1669 close(packet_get_connection_in());
1671 close(packet_get_connection_in());
1672 close(packet_get_connection_out());
1675 * Close all descriptors related to channels. They will still remain
1676 * open in the parent.
1678 /* XXX better use close-on-exec? -markus */
1679 channel_close_all();
1682 * Close any extra file descriptors. Note that there may still be
1683 * descriptors left by system functions. They will be closed later.
1688 * Close any extra open file descriptors so that we don't have them
1689 * hanging around in clients. Note that we want to do this after
1690 * initgroups, because at least on Solaris 2.3 it leaves file
1693 closefrom(STDERR_FILENO + 1);
1697 * Performs common processing for the child, such as setting up the
1698 * environment, closing extra file descriptors, setting the user and group
1699 * ids, and executing the command or shell.
1703 do_child(Session *s, const char *command)
1705 struct ssh *ssh = active_state; /* XXX */
1706 extern char **environ;
1708 char *argv[ARGV_MAX];
1709 const char *shell, *shell0, *hostname = NULL;
1710 struct passwd *pw = s->pw;
1713 /* remove hostkey from the child's memory */
1714 destroy_sensitive_data();
1716 /* Force a password change */
1717 if (s->authctxt->force_pwchange) {
1718 do_setusercontext(pw);
1724 /* login(1) is only called if we execute the login shell */
1725 if (options.use_login && command != NULL)
1726 options.use_login = 0;
1729 cray_setup(pw->pw_uid, pw->pw_name, command);
1730 #endif /* _UNICOS */
1733 * Login(1) does this as well, and it needs uid 0 for the "-h"
1734 * switch, so we let login(1) to this for us.
1736 if (!options.use_login) {
1738 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1739 if (!check_quietlogin(s, command))
1741 #else /* HAVE_OSF_SIA */
1742 /* When PAM is enabled we rely on it to do the nologin check */
1743 if (!options.use_pam)
1745 do_setusercontext(pw);
1747 * PAM session modules in do_setusercontext may have
1748 * generated messages, so if this in an interactive
1749 * login then display them too.
1751 if (!check_quietlogin(s, command))
1753 #endif /* HAVE_OSF_SIA */
1757 if (options.use_pam && !options.use_login && !is_pam_session_open()) {
1758 debug3("PAM session not opened, exiting");
1765 * Get the shell from the password data. An empty shell field is
1766 * legal, and means /bin/sh.
1768 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1771 * Make sure $SHELL points to the shell from the password file,
1772 * even if shell is overridden from login.conf
1774 env = do_setup_env(s, shell);
1776 #ifdef HAVE_LOGIN_CAP
1777 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1780 /* we have to stash the hostname before we close our socket. */
1781 if (options.use_login)
1782 hostname = session_get_remote_name_or_ip(ssh, utmp_len,
1785 * Close the connection descriptors; note that this is the child, and
1786 * the server will still have the socket open, and it is important
1787 * that we do not shutdown it. Note that the descriptors cannot be
1788 * closed before building the environment, as we call
1789 * ssh_remote_ipaddr there.
1794 * Must take new environment into use so that .ssh/rc,
1795 * /etc/ssh/sshrc and xauth are run in the proper environment.
1799 #if defined(KRB5) && defined(USE_AFS)
1801 * At this point, we check to see if AFS is active and if we have
1802 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1803 * if we can (and need to) extend the ticket into an AFS token. If
1804 * we don't do this, we run into potential problems if the user's
1805 * home directory is in AFS and it's not world-readable.
1808 if (options.kerberos_get_afs_token && k_hasafs() &&
1809 (s->authctxt->krb5_ctx != NULL)) {
1812 debug("Getting AFS token");
1816 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1817 krb5_afslog(s->authctxt->krb5_ctx,
1818 s->authctxt->krb5_fwd_ccache, cell, NULL);
1820 krb5_afslog_home(s->authctxt->krb5_ctx,
1821 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1825 /* Change current directory to the user's home directory. */
1826 if (chdir(pw->pw_dir) < 0) {
1827 /* Suppress missing homedir warning for chroot case */
1828 #ifdef HAVE_LOGIN_CAP
1829 r = login_getcapbool(lc, "requirehome", 0);
1831 if (r || !in_chroot) {
1832 fprintf(stderr, "Could not chdir to home "
1833 "directory %s: %s\n", pw->pw_dir,
1840 closefrom(STDERR_FILENO + 1);
1842 if (!options.use_login)
1843 do_rc_files(s, shell);
1845 /* restore SIGPIPE for child */
1846 signal(SIGPIPE, SIG_DFL);
1848 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1849 printf("This service allows sftp connections only.\n");
1852 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1853 extern int optind, optreset;
1857 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1858 args = xstrdup(command ? command : "sftp-server");
1859 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1860 if (i < ARGV_MAX - 1)
1863 optind = optreset = 1;
1864 __progname = argv[0];
1866 ssh_selinux_change_context("sftpd_t");
1868 exit(sftp_server_main(i, argv, s->pw));
1873 if (options.use_login) {
1874 launch_login(pw, hostname);
1878 /* Get the last component of the shell name. */
1879 if ((shell0 = strrchr(shell, '/')) != NULL)
1885 * If we have no command, execute the shell. In this case, the shell
1886 * name to be passed in argv[0] is preceded by '-' to indicate that
1887 * this is a login shell.
1892 /* Start the shell. Set initial character to '-'. */
1895 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1896 >= sizeof(argv0) - 1) {
1902 /* Execute the shell. */
1905 execve(shell, argv, env);
1907 /* Executing the shell failed. */
1912 * Execute the command using the user's shell. This uses the -c
1913 * option to execute the command.
1915 argv[0] = (char *) shell0;
1917 argv[2] = (char *) command;
1919 execve(shell, argv, env);
1925 session_unused(int id)
1927 debug3("%s: session id %d unused", __func__, id);
1928 if (id >= options.max_sessions ||
1929 id >= sessions_nalloc) {
1930 fatal("%s: insane session id %d (max %d nalloc %d)",
1931 __func__, id, options.max_sessions, sessions_nalloc);
1933 memset(&sessions[id], 0, sizeof(*sessions));
1934 sessions[id].self = id;
1935 sessions[id].used = 0;
1936 sessions[id].chanid = -1;
1937 sessions[id].ptyfd = -1;
1938 sessions[id].ttyfd = -1;
1939 sessions[id].ptymaster = -1;
1940 sessions[id].x11_chanids = NULL;
1941 sessions[id].next_unused = sessions_first_unused;
1942 sessions_first_unused = id;
1950 if (sessions_first_unused == -1) {
1951 if (sessions_nalloc >= options.max_sessions)
1953 debug2("%s: allocate (allocated %d max %d)",
1954 __func__, sessions_nalloc, options.max_sessions);
1955 tmp = xreallocarray(sessions, sessions_nalloc + 1,
1958 error("%s: cannot allocate %d sessions",
1959 __func__, sessions_nalloc + 1);
1963 session_unused(sessions_nalloc++);
1966 if (sessions_first_unused >= sessions_nalloc ||
1967 sessions_first_unused < 0) {
1968 fatal("%s: insane first_unused %d max %d nalloc %d",
1969 __func__, sessions_first_unused, options.max_sessions,
1973 s = &sessions[sessions_first_unused];
1975 fatal("%s: session %d already used",
1976 __func__, sessions_first_unused);
1978 sessions_first_unused = s->next_unused;
1980 s->next_unused = -1;
1981 debug("session_new: session %d", s->self);
1990 for (i = 0; i < sessions_nalloc; i++) {
1991 Session *s = &sessions[i];
1993 debug("dump: used %d next_unused %d session %d %p "
1994 "channel %d pid %ld",
2005 session_open(Authctxt *authctxt, int chanid)
2007 Session *s = session_new();
2008 debug("session_open: channel %d", chanid);
2010 error("no more sessions");
2013 s->authctxt = authctxt;
2014 s->pw = authctxt->pw;
2015 if (s->pw == NULL || !authctxt->valid)
2016 fatal("no user for session %d", s->self);
2017 debug("session_open: session %d: link with channel %d", s->self, chanid);
2023 session_by_tty(char *tty)
2026 for (i = 0; i < sessions_nalloc; i++) {
2027 Session *s = &sessions[i];
2028 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
2029 debug("session_by_tty: session %d tty %s", i, tty);
2033 debug("session_by_tty: unknown tty %.100s", tty);
2039 session_by_channel(int id)
2042 for (i = 0; i < sessions_nalloc; i++) {
2043 Session *s = &sessions[i];
2044 if (s->used && s->chanid == id) {
2045 debug("session_by_channel: session %d channel %d",
2050 debug("session_by_channel: unknown channel %d", id);
2056 session_by_x11_channel(int id)
2060 for (i = 0; i < sessions_nalloc; i++) {
2061 Session *s = &sessions[i];
2063 if (s->x11_chanids == NULL || !s->used)
2065 for (j = 0; s->x11_chanids[j] != -1; j++) {
2066 if (s->x11_chanids[j] == id) {
2067 debug("session_by_x11_channel: session %d "
2068 "channel %d", s->self, id);
2073 debug("session_by_x11_channel: unknown channel %d", id);
2079 session_by_pid(pid_t pid)
2082 debug("session_by_pid: pid %ld", (long)pid);
2083 for (i = 0; i < sessions_nalloc; i++) {
2084 Session *s = &sessions[i];
2085 if (s->used && s->pid == pid)
2088 error("session_by_pid: unknown pid %ld", (long)pid);
2094 session_window_change_req(Session *s)
2096 s->col = packet_get_int();
2097 s->row = packet_get_int();
2098 s->xpixel = packet_get_int();
2099 s->ypixel = packet_get_int();
2101 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2106 session_pty_req(Session *s)
2111 if (no_pty_flag || !options.permit_tty) {
2112 debug("Allocating a pty not permitted for this authentication.");
2115 if (s->ttyfd != -1) {
2116 packet_disconnect("Protocol error: you already have a pty.");
2120 s->term = packet_get_string(&len);
2123 s->col = packet_get_int();
2124 s->row = packet_get_int();
2126 s->row = packet_get_int();
2127 s->col = packet_get_int();
2129 s->xpixel = packet_get_int();
2130 s->ypixel = packet_get_int();
2132 if (strcmp(s->term, "") == 0) {
2137 /* Allocate a pty and open it. */
2138 debug("Allocating pty.");
2139 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
2145 error("session_pty_req: session %d alloc failed", s->self);
2148 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
2150 /* for SSH1 the tty modes length is not given */
2152 n_bytes = packet_remaining();
2153 tty_parse_modes(s->ttyfd, &n_bytes);
2156 pty_setowner(s->pw, s->tty);
2158 /* Set window size from the packet. */
2159 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
2162 session_proctitle(s);
2167 session_subsystem_req(Session *s)
2175 s->subsys = packet_get_string(&len);
2177 debug2("subsystem request for %.100s by user %s", s->subsys,
2180 for (i = 0; i < options.num_subsystems; i++) {
2181 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
2182 prog = options.subsystem_command[i];
2183 cmd = options.subsystem_args[i];
2184 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
2185 s->is_subsystem = SUBSYSTEM_INT_SFTP;
2186 debug("subsystem: %s", prog);
2188 if (stat(prog, &st) < 0)
2189 debug("subsystem: cannot stat %s: %s",
2190 prog, strerror(errno));
2191 s->is_subsystem = SUBSYSTEM_EXT;
2192 debug("subsystem: exec() %s", cmd);
2194 success = do_exec(s, cmd) == 0;
2200 logit("subsystem request for %.100s by user %s failed, "
2201 "subsystem not found", s->subsys, s->pw->pw_name);
2207 session_x11_req(Session *s)
2211 if (s->auth_proto != NULL || s->auth_data != NULL) {
2212 error("session_x11_req: session %d: "
2213 "x11 forwarding already active", s->self);
2216 s->single_connection = packet_get_char();
2217 s->auth_proto = packet_get_string(NULL);
2218 s->auth_data = packet_get_string(NULL);
2219 s->screen = packet_get_int();
2222 if (xauth_valid_string(s->auth_proto) &&
2223 xauth_valid_string(s->auth_data))
2224 success = session_setup_x11fwd(s);
2227 error("Invalid X11 forwarding data");
2230 free(s->auth_proto);
2232 s->auth_proto = NULL;
2233 s->auth_data = NULL;
2239 session_shell_req(Session *s)
2242 return do_exec(s, NULL) == 0;
2246 session_exec_req(Session *s)
2250 char *command = packet_get_string(&len);
2252 success = do_exec(s, command) == 0;
2258 session_break_req(Session *s)
2261 packet_get_int(); /* ignored */
2264 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2270 session_env_req(Session *s)
2273 u_int name_len, val_len, i;
2275 name = packet_get_cstring(&name_len);
2276 val = packet_get_cstring(&val_len);
2279 /* Don't set too many environment variables */
2280 if (s->num_env > 128) {
2281 debug2("Ignoring env request %s: too many env vars", name);
2285 for (i = 0; i < options.num_accept_env; i++) {
2286 if (match_pattern(name, options.accept_env[i])) {
2287 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2288 s->env = xreallocarray(s->env, s->num_env + 1,
2290 s->env[s->num_env].name = name;
2291 s->env[s->num_env].val = val;
2296 debug2("Ignoring env request %s: disallowed name", name);
2305 session_auth_agent_req(Session *s)
2307 static int called = 0;
2309 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) {
2310 debug("session_auth_agent_req: no_agent_forwarding_flag");
2317 return auth_input_request_forwarding(s->pw);
2322 session_input_channel_req(Channel *c, const char *rtype)
2327 if ((s = session_by_channel(c->self)) == NULL) {
2328 logit("session_input_channel_req: no session %d req %.100s",
2332 debug("session_input_channel_req: session %d req %s", s->self, rtype);
2335 * a session is in LARVAL state until a shell, a command
2336 * or a subsystem is executed
2338 if (c->type == SSH_CHANNEL_LARVAL) {
2339 if (strcmp(rtype, "shell") == 0) {
2340 success = session_shell_req(s);
2341 } else if (strcmp(rtype, "exec") == 0) {
2342 success = session_exec_req(s);
2343 } else if (strcmp(rtype, "pty-req") == 0) {
2344 success = session_pty_req(s);
2345 } else if (strcmp(rtype, "x11-req") == 0) {
2346 success = session_x11_req(s);
2347 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2348 success = session_auth_agent_req(s);
2349 } else if (strcmp(rtype, "subsystem") == 0) {
2350 success = session_subsystem_req(s);
2351 } else if (strcmp(rtype, "env") == 0) {
2352 success = session_env_req(s);
2355 if (strcmp(rtype, "window-change") == 0) {
2356 success = session_window_change_req(s);
2357 } else if (strcmp(rtype, "break") == 0) {
2358 success = session_break_req(s);
2365 session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr,
2369 fatal("session_set_fds: called for proto != 2.0");
2371 * now that have a child and a pipe to the child,
2372 * we can activate our channel and register the fd's
2374 if (s->chanid == -1)
2375 fatal("no channel for session %d", s->self);
2376 channel_set_fds(s->chanid,
2378 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2379 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2383 * Function to perform pty cleanup. Also called if we get aborted abnormally
2384 * (e.g., due to a dropped connection).
2387 session_pty_cleanup2(Session *s)
2390 error("session_pty_cleanup: no session");
2396 debug("session_pty_cleanup: session %d release %s", s->self, s->tty);
2398 /* Record that the user has logged out. */
2400 record_logout(s->pid, s->tty, s->pw->pw_name);
2402 /* Release the pseudo-tty. */
2404 pty_release(s->tty);
2407 * Close the server side of the socket pairs. We must do this after
2408 * the pty cleanup, so that another process doesn't get this pty
2409 * while we're still cleaning up.
2411 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2412 error("close(s->ptymaster/%d): %s",
2413 s->ptymaster, strerror(errno));
2415 /* unlink pty from session */
2420 session_pty_cleanup(Session *s)
2422 PRIVSEP(session_pty_cleanup2(s));
2428 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2443 return "SIG@openssh.com";
2447 session_close_x11(int id)
2451 if ((c = channel_by_id(id)) == NULL) {
2452 debug("session_close_x11: x11 channel %d missing", id);
2454 /* Detach X11 listener */
2455 debug("session_close_x11: detach x11 channel %d", id);
2456 channel_cancel_cleanup(id);
2457 if (c->ostate != CHAN_OUTPUT_CLOSED)
2463 session_close_single_x11(int id, void *arg)
2468 debug3("session_close_single_x11: channel %d", id);
2469 channel_cancel_cleanup(id);
2470 if ((s = session_by_x11_channel(id)) == NULL)
2471 fatal("session_close_single_x11: no x11 channel %d", id);
2472 for (i = 0; s->x11_chanids[i] != -1; i++) {
2473 debug("session_close_single_x11: session %d: "
2474 "closing channel %d", s->self, s->x11_chanids[i]);
2476 * The channel "id" is already closing, but make sure we
2477 * close all of its siblings.
2479 if (s->x11_chanids[i] != id)
2480 session_close_x11(s->x11_chanids[i]);
2482 free(s->x11_chanids);
2483 s->x11_chanids = NULL;
2486 free(s->auth_proto);
2487 s->auth_proto = NULL;
2489 s->auth_data = NULL;
2490 free(s->auth_display);
2491 s->auth_display = NULL;
2495 session_exit_message(Session *s, int status)
2499 if ((c = channel_lookup(s->chanid)) == NULL)
2500 fatal("session_exit_message: session %d: no channel %d",
2501 s->self, s->chanid);
2502 debug("session_exit_message: session %d channel %d pid %ld",
2503 s->self, s->chanid, (long)s->pid);
2505 if (WIFEXITED(status)) {
2506 channel_request_start(s->chanid, "exit-status", 0);
2507 packet_put_int(WEXITSTATUS(status));
2509 } else if (WIFSIGNALED(status)) {
2510 channel_request_start(s->chanid, "exit-signal", 0);
2511 packet_put_cstring(sig2name(WTERMSIG(status)));
2513 packet_put_char(WCOREDUMP(status)? 1 : 0);
2514 #else /* WCOREDUMP */
2516 #endif /* WCOREDUMP */
2517 packet_put_cstring("");
2518 packet_put_cstring("");
2521 /* Some weird exit cause. Just exit. */
2522 packet_disconnect("wait returned status %04x.", status);
2525 /* disconnect channel */
2526 debug("session_exit_message: release channel %d", s->chanid);
2529 * Adjust cleanup callback attachment to send close messages when
2530 * the channel gets EOF. The session will be then be closed
2531 * by session_close_by_channel when the childs close their fds.
2533 channel_register_cleanup(c->self, session_close_by_channel, 1);
2536 * emulate a write failure with 'chan_write_failed', nobody will be
2537 * interested in data we write.
2538 * Note that we must not call 'chan_read_failed', since there could
2539 * be some more data waiting in the pipe.
2541 if (c->ostate != CHAN_OUTPUT_CLOSED)
2542 chan_write_failed(c);
2546 session_close(Session *s)
2548 struct ssh *ssh = active_state; /* XXX */
2551 verbose("Close session: user %s from %.200s port %d id %d",
2553 ssh_remote_ipaddr(ssh),
2554 ssh_remote_port(ssh),
2558 session_pty_cleanup(s);
2561 free(s->x11_chanids);
2562 free(s->auth_display);
2564 free(s->auth_proto);
2566 if (s->env != NULL) {
2567 for (i = 0; i < s->num_env; i++) {
2568 free(s->env[i].name);
2569 free(s->env[i].val);
2573 session_proctitle(s);
2574 session_unused(s->self);
2578 session_close_by_pid(pid_t pid, int status)
2580 Session *s = session_by_pid(pid);
2582 debug("session_close_by_pid: no session for pid %ld",
2586 if (s->chanid != -1)
2587 session_exit_message(s, status);
2589 session_pty_cleanup(s);
2594 * this is called when a channel dies before
2595 * the session 'child' itself dies
2598 session_close_by_channel(int id, void *arg)
2600 Session *s = session_by_channel(id);
2604 debug("session_close_by_channel: no session for id %d", id);
2607 debug("session_close_by_channel: channel %d child %ld",
2610 debug("session_close_by_channel: channel %d: has child", id);
2612 * delay detach of session, but release pty, since
2613 * the fd's to the child are already closed
2616 session_pty_cleanup(s);
2619 /* detach by removing callback */
2620 channel_cancel_cleanup(s->chanid);
2622 /* Close any X11 listeners associated with this session */
2623 if (s->x11_chanids != NULL) {
2624 for (i = 0; s->x11_chanids[i] != -1; i++) {
2625 session_close_x11(s->x11_chanids[i]);
2626 s->x11_chanids[i] = -1;
2635 session_destroy_all(void (*closefunc)(Session *))
2638 for (i = 0; i < sessions_nalloc; i++) {
2639 Session *s = &sessions[i];
2641 if (closefunc != NULL)
2650 session_tty_list(void)
2652 static char buf[1024];
2657 for (i = 0; i < sessions_nalloc; i++) {
2658 Session *s = &sessions[i];
2659 if (s->used && s->ttyfd != -1) {
2661 if (strncmp(s->tty, "/dev/", 5) != 0) {
2662 cp = strrchr(s->tty, '/');
2663 cp = (cp == NULL) ? s->tty : cp + 1;
2668 strlcat(buf, ",", sizeof buf);
2669 strlcat(buf, cp, sizeof buf);
2673 strlcpy(buf, "notty", sizeof buf);
2678 session_proctitle(Session *s)
2681 error("no user for session %d", s->self);
2683 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2687 session_setup_x11fwd(Session *s)
2690 char display[512], auth_display[512];
2691 char hostname[NI_MAXHOST];
2694 if (no_x11_forwarding_flag) {
2695 packet_send_debug("X11 forwarding disabled in user configuration file.");
2698 if (!options.x11_forwarding) {
2699 debug("X11 forwarding disabled in server configuration file.");
2702 if (options.xauth_location == NULL ||
2703 (stat(options.xauth_location, &st) == -1)) {
2704 packet_send_debug("No xauth program; cannot forward with spoofing.");
2707 if (options.use_login) {
2708 packet_send_debug("X11 forwarding disabled; "
2709 "not compatible with UseLogin=yes.");
2712 if (s->display != NULL) {
2713 debug("X11 display already set.");
2716 if (x11_create_display_inet(options.x11_display_offset,
2717 options.x11_use_localhost, s->single_connection,
2718 &s->display_number, &s->x11_chanids) == -1) {
2719 debug("x11_create_display_inet failed.");
2722 for (i = 0; s->x11_chanids[i] != -1; i++) {
2723 channel_register_cleanup(s->x11_chanids[i],
2724 session_close_single_x11, 0);
2727 /* Set up a suitable value for the DISPLAY variable. */
2728 if (gethostname(hostname, sizeof(hostname)) < 0)
2729 fatal("gethostname: %.100s", strerror(errno));
2731 * auth_display must be used as the displayname when the
2732 * authorization entry is added with xauth(1). This will be
2733 * different than the DISPLAY string for localhost displays.
2735 if (options.x11_use_localhost) {
2736 snprintf(display, sizeof display, "localhost:%u.%u",
2737 s->display_number, s->screen);
2738 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2739 s->display_number, s->screen);
2740 s->display = xstrdup(display);
2741 s->auth_display = xstrdup(auth_display);
2743 #ifdef IPADDR_IN_DISPLAY
2745 struct in_addr my_addr;
2747 he = gethostbyname(hostname);
2749 error("Can't get IP address for X11 DISPLAY.");
2750 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2753 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2754 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2755 s->display_number, s->screen);
2757 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2758 s->display_number, s->screen);
2760 s->display = xstrdup(display);
2761 s->auth_display = xstrdup(display);
2768 do_authenticated2(Authctxt *authctxt)
2770 server_loop2(authctxt);
2774 do_cleanup(Authctxt *authctxt)
2776 static int called = 0;
2778 debug("do_cleanup");
2780 /* no cleanup if we're in the child for login shell */
2784 /* avoid double cleanup */
2789 if (authctxt == NULL)
2793 if (options.use_pam) {
2795 sshpam_thread_cleanup();
2799 if (!authctxt->authenticated)
2803 if (options.kerberos_ticket_cleanup &&
2805 krb5_cleanup_proc(authctxt);
2809 if (compat20 && options.gss_cleanup_creds)
2810 ssh_gssapi_cleanup_creds();
2813 /* remove agent socket */
2814 auth_sock_cleanup_proc(authctxt->pw);
2817 * Cleanup ptys/utmp only if privsep is disabled,
2818 * or if running in monitor.
2820 if (!use_privsep || mm_is_monitor())
2821 session_destroy_all(session_pty_cleanup2);
2824 /* Return a name for the remote host that fits inside utmp_size */
2827 session_get_remote_name_or_ip(struct ssh *ssh, u_int utmp_size, int use_dns)
2829 const char *remote = "";
2832 remote = auth_get_canonical_hostname(ssh, use_dns);
2833 if (utmp_size == 0 || strlen(remote) > utmp_size)
2834 remote = ssh_remote_ipaddr(ssh);