1 /* $OpenBSD: session.c,v 1.315 2019/02/22 03:37:11 djm Exp $ */
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
12 * SSH2 support by Markus Friedl.
13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38 #include <sys/types.h>
39 #include <sys/param.h>
40 #ifdef HAVE_SYS_STAT_H
41 # include <sys/stat.h>
43 #include <sys/socket.h>
47 #include <arpa/inet.h>
66 #include "openbsd-compat/sys-queue.h"
85 #include "auth-options.h"
87 #include "pathnames.h"
92 #include "serverloop.h"
96 #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(struct ssh *, Session *, int, int, int, int, int);
118 void session_pty_cleanup(Session *);
119 void session_proctitle(Session *);
120 int session_setup_x11fwd(struct ssh *, Session *);
121 int do_exec_pty(struct ssh *, Session *, const char *);
122 int do_exec_no_pty(struct ssh *, Session *, const char *);
123 int do_exec(struct ssh *, Session *, const char *);
124 void do_login(struct ssh *, Session *, const char *);
125 void do_child(struct ssh *, Session *, const char *);
127 int check_quietlogin(Session *, const char *);
129 static void do_authenticated2(struct ssh *, Authctxt *);
131 static int session_pty_req(struct ssh *, Session *);
134 extern ServerOptions options;
135 extern char *__progname;
136 extern int debug_flag;
137 extern u_int utmp_len;
138 extern int startup_pipe;
139 extern void destroy_sensitive_data(void);
140 extern struct sshbuf *loginmsg;
141 extern struct sshauthopt *auth_opts;
142 extern char *tun_fwd_ifnames; /* serverloop.c */
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;
162 static int in_chroot = 0;
164 /* File containing userauth info, if ExposeAuthInfo set */
165 static char *auth_info_file = NULL;
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 ssh *ssh, 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 ssh_packet_send_debug(ssh, "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(ssh, "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 temporarily_use_uid(pw);
237 rmdir(auth_sock_dir);
243 auth_sock_name = NULL;
244 auth_sock_dir = NULL;
249 display_loginmsg(void)
253 if (sshbuf_len(loginmsg) == 0)
255 if ((r = sshbuf_put_u8(loginmsg, 0)) != 0)
256 fatal("%s: buffer error: %s", __func__, ssh_err(r));
257 printf("%s", (char *)sshbuf_ptr(loginmsg));
258 sshbuf_reset(loginmsg);
262 prepare_auth_info_file(struct passwd *pw, struct sshbuf *info)
264 int fd = -1, success = 0;
266 if (!options.expose_userauth_info || info == NULL)
269 temporarily_use_uid(pw);
270 auth_info_file = xstrdup("/tmp/sshauth.XXXXXXXXXXXXXXX");
271 if ((fd = mkstemp(auth_info_file)) == -1) {
272 error("%s: mkstemp: %s", __func__, strerror(errno));
275 if (atomicio(vwrite, fd, sshbuf_mutable_ptr(info),
276 sshbuf_len(info)) != sshbuf_len(info)) {
277 error("%s: write: %s", __func__, strerror(errno));
280 if (close(fd) != 0) {
281 error("%s: close: %s", __func__, strerror(errno));
289 free(auth_info_file);
290 auth_info_file = NULL;
296 set_fwdpermit_from_authopts(struct ssh *ssh, const struct sshauthopt *opts)
298 char *tmp, *cp, *host;
302 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0) {
303 channel_clear_permission(ssh, FORWARD_USER, FORWARD_LOCAL);
304 for (i = 0; i < auth_opts->npermitopen; i++) {
305 tmp = cp = xstrdup(auth_opts->permitopen[i]);
306 /* This shouldn't fail as it has already been checked */
307 if ((host = hpdelim(&cp)) == NULL)
308 fatal("%s: internal error: hpdelim", __func__);
309 host = cleanhostname(host);
310 if (cp == NULL || (port = permitopen_port(cp)) < 0)
311 fatal("%s: internal error: permitopen port",
313 channel_add_permission(ssh,
314 FORWARD_USER, FORWARD_LOCAL, host, port);
318 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) != 0) {
319 channel_clear_permission(ssh, FORWARD_USER, FORWARD_REMOTE);
320 for (i = 0; i < auth_opts->npermitlisten; i++) {
321 tmp = cp = xstrdup(auth_opts->permitlisten[i]);
322 /* This shouldn't fail as it has already been checked */
323 if ((host = hpdelim(&cp)) == NULL)
324 fatal("%s: internal error: hpdelim", __func__);
325 host = cleanhostname(host);
326 if (cp == NULL || (port = permitopen_port(cp)) < 0)
327 fatal("%s: internal error: permitlisten port",
329 channel_add_permission(ssh,
330 FORWARD_USER, FORWARD_REMOTE, host, port);
337 do_authenticated(struct ssh *ssh, Authctxt *authctxt)
339 setproctitle("%s", authctxt->pw->pw_name);
341 auth_log_authopts("active", auth_opts, 0);
343 /* setup the channel layer */
344 /* XXX - streamlocal? */
345 set_fwdpermit_from_authopts(ssh, auth_opts);
347 if (!auth_opts->permit_port_forwarding_flag ||
348 options.disable_forwarding) {
349 channel_disable_admin(ssh, FORWARD_LOCAL);
350 channel_disable_admin(ssh, FORWARD_REMOTE);
352 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) == 0)
353 channel_disable_admin(ssh, FORWARD_LOCAL);
355 channel_permit_all(ssh, FORWARD_LOCAL);
356 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0)
357 channel_disable_admin(ssh, FORWARD_REMOTE);
359 channel_permit_all(ssh, FORWARD_REMOTE);
361 auth_debug_send(ssh);
363 prepare_auth_info_file(authctxt->pw, authctxt->session_info);
365 do_authenticated2(ssh, authctxt);
367 do_cleanup(ssh, authctxt);
370 /* Check untrusted xauth strings for metacharacters */
372 xauth_valid_string(const char *s)
376 for (i = 0; s[i] != '\0'; i++) {
377 if (!isalnum((u_char)s[i]) &&
378 s[i] != '.' && s[i] != ':' && s[i] != '/' &&
379 s[i] != '-' && s[i] != '_')
387 * This is called to fork and execute a command when we have no tty. This
388 * will call do_child from the child, and server_loop from the parent after
389 * setting up file descriptors and such.
392 do_exec_no_pty(struct ssh *ssh, Session *s, const char *command)
396 int pin[2], pout[2], perr[2];
399 fatal("do_exec_no_pty: no session");
401 /* Allocate pipes for communicating with the program. */
403 error("%s: pipe in: %.100s", __func__, strerror(errno));
406 if (pipe(pout) < 0) {
407 error("%s: pipe out: %.100s", __func__, strerror(errno));
412 if (pipe(perr) < 0) {
413 error("%s: pipe err: %.100s", __func__,
422 int inout[2], err[2];
425 fatal("do_exec_no_pty: no session");
427 /* Uses socket pairs to communicate with the program. */
428 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) {
429 error("%s: socketpair #1: %.100s", __func__, strerror(errno));
432 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) {
433 error("%s: socketpair #2: %.100s", __func__,
441 session_proctitle(s);
443 /* Fork the child. */
444 switch ((pid = fork())) {
446 error("%s: fork: %.100s", __func__, strerror(errno));
465 * Create a new session and process group since the 4.4BSD
466 * setlogin() affects the entire process group.
469 error("setsid failed: %.100s", strerror(errno));
473 * Redirect stdin. We close the parent side of the socket
474 * pair, and make the child side the standard input.
477 if (dup2(pin[0], 0) < 0)
478 perror("dup2 stdin");
481 /* Redirect stdout. */
483 if (dup2(pout[1], 1) < 0)
484 perror("dup2 stdout");
487 /* Redirect stderr. */
489 if (dup2(perr[1], 2) < 0)
490 perror("dup2 stderr");
494 * Redirect stdin, stdout, and stderr. Stdin and stdout will
495 * use the same socket, as some programs (particularly rdist)
496 * seem to depend on it.
500 if (dup2(inout[0], 0) < 0) /* stdin */
501 perror("dup2 stdin");
502 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */
503 perror("dup2 stdout");
505 if (dup2(err[0], 2) < 0) /* stderr */
506 perror("dup2 stderr");
510 /* Do processing for the child (exec command etc). */
511 do_child(ssh, s, command);
518 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
522 /* Set interactive/non-interactive mode. */
523 ssh_packet_set_interactive(ssh, s->display != NULL,
524 options.ip_qos_interactive, options.ip_qos_bulk);
527 * Clear loginmsg, since it's the child's responsibility to display
528 * it to the user, otherwise multiple sessions may accumulate
529 * multiple copies of the login messages.
531 sshbuf_reset(loginmsg);
534 /* We are the parent. Close the child sides of the pipes. */
539 session_set_fds(ssh, s, pin[1], pout[0], perr[0],
542 /* We are the parent. Close the child sides of the socket pairs. */
547 * Enter the interactive session. Note: server_loop must be able to
548 * handle the case that fdin and fdout are the same.
550 session_set_fds(ssh, s, inout[1], inout[1], err[1],
557 * This is called to fork and execute a command when we have a tty. This
558 * will call do_child from the child, and server_loop from the parent after
559 * setting up file descriptors, controlling tty, updating wtmp, utmp,
560 * lastlog, and other such operations.
563 do_exec_pty(struct ssh *ssh, Session *s, const char *command)
565 int fdout, ptyfd, ttyfd, ptymaster;
569 fatal("do_exec_pty: no session");
574 * Create another descriptor of the pty master side for use as the
575 * standard input. We could use the original descriptor, but this
576 * simplifies code in server_loop. The descriptor is bidirectional.
577 * Do this before forking (and cleanup in the child) so as to
578 * detect and gracefully fail out-of-fd conditions.
580 if ((fdout = dup(ptyfd)) < 0) {
581 error("%s: dup #1: %s", __func__, strerror(errno));
586 /* we keep a reference to the pty master */
587 if ((ptymaster = dup(ptyfd)) < 0) {
588 error("%s: dup #2: %s", __func__, strerror(errno));
595 /* Fork the child. */
596 switch ((pid = fork())) {
598 error("%s: fork: %.100s", __func__, strerror(errno));
610 /* Close the master side of the pseudo tty. */
613 /* Make the pseudo tty our controlling tty. */
614 pty_make_controlling_tty(&ttyfd, s->tty);
616 /* Redirect stdin/stdout/stderr from the pseudo tty. */
617 if (dup2(ttyfd, 0) < 0)
618 error("dup2 stdin: %s", strerror(errno));
619 if (dup2(ttyfd, 1) < 0)
620 error("dup2 stdout: %s", strerror(errno));
621 if (dup2(ttyfd, 2) < 0)
622 error("dup2 stderr: %s", strerror(errno));
624 /* Close the extra descriptor for the pseudo tty. */
627 /* record login, etc. similar to login(1) */
629 do_login(ssh, s, command);
632 * Do common processing for the child, such as execing
635 do_child(ssh, s, command);
642 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE);
647 /* Parent. Close the slave side of the pseudo tty. */
650 /* Enter interactive session. */
651 s->ptymaster = ptymaster;
652 ssh_packet_set_interactive(ssh, 1,
653 options.ip_qos_interactive, options.ip_qos_bulk);
654 session_set_fds(ssh, s, ptyfd, fdout, -1, 1, 1);
659 * This is called to fork and execute a command. If another command is
660 * to be forced, execute that instead.
663 do_exec(struct ssh *ssh, Session *s, const char *command)
666 const char *forced = NULL, *tty = NULL;
667 char session_type[1024];
669 if (options.adm_forced_command) {
670 original_command = command;
671 command = options.adm_forced_command;
673 } else if (auth_opts->force_command != NULL) {
674 original_command = command;
675 command = auth_opts->force_command;
676 forced = "(key-option)";
679 if (forced != NULL) {
681 if (IS_INTERNAL_SFTP(command)) {
682 s->is_subsystem = s->is_subsystem ?
683 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR;
684 } else if (s->is_subsystem)
685 s->is_subsystem = SUBSYSTEM_EXT;
686 snprintf(session_type, sizeof(session_type),
687 "forced-command %s '%.900s'", forced, command);
688 } else if (s->is_subsystem) {
689 snprintf(session_type, sizeof(session_type),
690 "subsystem '%.900s'", s->subsys);
691 } else if (command == NULL) {
692 snprintf(session_type, sizeof(session_type), "shell");
694 /* NB. we don't log unforced commands to preserve privacy */
695 snprintf(session_type, sizeof(session_type), "command");
698 if (s->ttyfd != -1) {
700 if (strncmp(tty, "/dev/", 5) == 0)
704 verbose("Starting session: %s%s%s for %s from %.200s port %d id %d",
706 tty == NULL ? "" : " on ",
707 tty == NULL ? "" : tty,
709 ssh_remote_ipaddr(ssh),
710 ssh_remote_port(ssh),
713 #ifdef SSH_AUDIT_EVENTS
715 PRIVSEP(audit_run_command(command));
716 else if (s->ttyfd == -1) {
717 char *shell = s->pw->pw_shell;
719 if (shell[0] == '\0') /* empty shell means /bin/sh */
721 PRIVSEP(audit_run_command(shell));
725 ret = do_exec_pty(ssh, s, command);
727 ret = do_exec_no_pty(ssh, s, command);
729 original_command = NULL;
732 * Clear loginmsg: it's the child's responsibility to display
733 * it to the user, otherwise multiple sessions may accumulate
734 * multiple copies of the login messages.
736 sshbuf_reset(loginmsg);
741 /* administrative, login(1)-like work */
743 do_login(struct ssh *ssh, Session *s, const char *command)
746 struct sockaddr_storage from;
747 struct passwd * pw = s->pw;
748 pid_t pid = getpid();
751 * Get IP address of client. If the connection is not a socket, let
752 * the address be 0.0.0.0.
754 memset(&from, 0, sizeof(from));
755 fromlen = sizeof(from);
756 if (ssh_packet_connection_is_on_socket(ssh)) {
757 if (getpeername(ssh_packet_get_connection_in(ssh),
758 (struct sockaddr *)&from, &fromlen) < 0) {
759 debug("getpeername: %.100s", strerror(errno));
764 /* Record that there was a login on that tty from the remote host. */
766 record_login(pid, s->tty, pw->pw_name, pw->pw_uid,
767 session_get_remote_name_or_ip(ssh, utmp_len,
769 (struct sockaddr *)&from, fromlen);
773 * If password change is needed, do it now.
774 * This needs to occur before the ~/.hushlogin check.
776 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) {
779 s->authctxt->force_pwchange = 0;
780 /* XXX - signal [net] parent to enable forwardings */
784 if (check_quietlogin(s, command))
793 * Display the message of the day.
801 if (options.print_motd) {
802 #ifdef HAVE_LOGIN_CAP
803 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd",
806 f = fopen("/etc/motd", "r");
809 while (fgets(buf, sizeof(buf), f))
818 * Check for quiet login, either .hushlogin or command given.
821 check_quietlogin(Session *s, const char *command)
824 struct passwd *pw = s->pw;
827 /* Return 1 if .hushlogin exists or a command given. */
830 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir);
831 #ifdef HAVE_LOGIN_CAP
832 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0)
835 if (stat(buf, &st) >= 0)
842 * Reads environment variables from the given file and adds/overrides them
843 * into the environment. If the file does not exist, this does nothing.
844 * Otherwise, it must consist of empty lines, comments (line starts with '#')
845 * and assignments of the form name=value. No other forms are allowed.
846 * If whitelist is not NULL, then it is interpreted as a pattern list and
847 * only variable names that match it will be accepted.
850 read_environment_file(char ***env, u_int *envsize,
851 const char *filename, const char *whitelist)
854 char *line = NULL, *cp, *value;
858 f = fopen(filename, "r");
862 while (getline(&line, &linesize, f) != -1) {
864 fatal("Too many lines in environment file %s", filename);
865 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
867 if (!*cp || *cp == '#' || *cp == '\n')
870 cp[strcspn(cp, "\n")] = '\0';
872 value = strchr(cp, '=');
874 fprintf(stderr, "Bad line %u in %.100s\n", lineno,
879 * Replace the equals sign by nul, and advance value to
884 if (whitelist != NULL &&
885 match_pattern_list(cp, whitelist, 0) != 1)
887 child_set_env(env, envsize, cp, value);
893 #ifdef HAVE_ETC_DEFAULT_LOGIN
895 * Return named variable from specified environment, or NULL if not present.
898 child_get_env(char **env, const char *name)
904 for (i=0; env[i] != NULL; i++)
905 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=')
906 return(env[i] + len + 1);
911 * Read /etc/default/login.
912 * We pick up the PATH (or SUPATH for root) and UMASK.
915 read_etc_default_login(char ***env, u_int *envsize, uid_t uid)
917 char **tmpenv = NULL, *var;
918 u_int i, tmpenvsize = 0;
922 * We don't want to copy the whole file to the child's environment,
923 * so we use a temporary environment and copy the variables we're
926 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login",
927 options.permit_user_env_whitelist);
933 var = child_get_env(tmpenv, "SUPATH");
935 var = child_get_env(tmpenv, "PATH");
937 child_set_env(env, envsize, "PATH", var);
939 if ((var = child_get_env(tmpenv, "UMASK")) != NULL)
940 if (sscanf(var, "%5lo", &mask) == 1)
943 for (i = 0; tmpenv[i] != NULL; i++)
947 #endif /* HAVE_ETC_DEFAULT_LOGIN */
950 copy_environment_blacklist(char **source, char ***env, u_int *envsize,
951 const char *blacklist)
953 char *var_name, *var_val;
959 for(i = 0; source[i] != NULL; i++) {
960 var_name = xstrdup(source[i]);
961 if ((var_val = strstr(var_name, "=")) == NULL) {
967 if (blacklist == NULL ||
968 match_pattern_list(var_name, blacklist, 0) != 1) {
969 debug3("Copy environment: %s=%s", var_name, var_val);
970 child_set_env(env, envsize, var_name, var_val);
978 copy_environment(char **source, char ***env, u_int *envsize)
980 copy_environment_blacklist(source, env, envsize, NULL);
984 do_setup_env(struct ssh *ssh, Session *s, const char *shell)
989 char *ocp, *cp, *value, **env, *laddr;
990 struct passwd *pw = s->pw;
991 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
995 /* Initialize the environment. */
997 env = xcalloc(envsize, sizeof(char *));
1002 * The Windows environment contains some setting which are
1003 * important for a running system. They must not be dropped.
1008 p = fetch_windows_environment();
1009 copy_environment(p, &env, &envsize);
1010 free_windows_environment(p);
1015 /* Allow any GSSAPI methods that we've used to alter
1016 * the childs environment as they see fit
1018 ssh_gssapi_do_child(&env, &envsize);
1021 /* Set basic environment. */
1022 for (i = 0; i < s->num_env; i++)
1023 child_set_env(&env, &envsize, s->env[i].name, s->env[i].val);
1025 child_set_env(&env, &envsize, "USER", pw->pw_name);
1026 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
1028 child_set_env(&env, &envsize, "LOGIN", pw->pw_name);
1030 child_set_env(&env, &envsize, "HOME", pw->pw_dir);
1031 #ifdef HAVE_LOGIN_CAP
1032 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0)
1033 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
1035 child_set_env(&env, &envsize, "PATH", getenv("PATH"));
1036 #else /* HAVE_LOGIN_CAP */
1037 # ifndef HAVE_CYGWIN
1039 * There's no standard path on Windows. The path contains
1040 * important components pointing to the system directories,
1041 * needed for loading shared libraries. So the path better
1042 * remains intact here.
1044 # ifdef HAVE_ETC_DEFAULT_LOGIN
1045 read_etc_default_login(&env, &envsize, pw->pw_uid);
1046 path = child_get_env(env, "PATH");
1047 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1048 if (path == NULL || *path == '\0') {
1049 child_set_env(&env, &envsize, "PATH",
1050 s->pw->pw_uid == 0 ? SUPERUSER_PATH : _PATH_STDPATH);
1052 # endif /* HAVE_CYGWIN */
1053 #endif /* HAVE_LOGIN_CAP */
1055 if (!options.use_pam) {
1056 snprintf(buf, sizeof buf, "%.200s/%.50s",
1057 _PATH_MAILDIR, pw->pw_name);
1058 child_set_env(&env, &envsize, "MAIL", buf);
1061 /* Normal systems set SHELL by default. */
1062 child_set_env(&env, &envsize, "SHELL", shell);
1065 child_set_env(&env, &envsize, "TZ", getenv("TZ"));
1067 child_set_env(&env, &envsize, "TERM", s->term);
1069 child_set_env(&env, &envsize, "DISPLAY", s->display);
1072 * Since we clear KRB5CCNAME at startup, if it's set now then it
1073 * must have been set by a native authentication method (eg AIX or
1074 * SIA), so copy it to the child.
1079 if ((cp = getenv("KRB5CCNAME")) != NULL)
1080 child_set_env(&env, &envsize, "KRB5CCNAME", cp);
1087 if ((cp = getenv("AUTHSTATE")) != NULL)
1088 child_set_env(&env, &envsize, "AUTHSTATE", cp);
1089 read_environment_file(&env, &envsize, "/etc/environment",
1090 options.permit_user_env_whitelist);
1094 if (s->authctxt->krb5_ccname)
1095 child_set_env(&env, &envsize, "KRB5CCNAME",
1096 s->authctxt->krb5_ccname);
1098 if (auth_sock_name != NULL)
1099 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
1103 /* Set custom environment options from pubkey authentication. */
1104 if (options.permit_user_env) {
1105 for (n = 0 ; n < auth_opts->nenv; n++) {
1106 ocp = xstrdup(auth_opts->env[n]);
1107 cp = strchr(ocp, '=');
1110 /* Apply PermitUserEnvironment whitelist */
1111 if (options.permit_user_env_whitelist == NULL ||
1112 match_pattern_list(ocp,
1113 options.permit_user_env_whitelist, 0) == 1)
1114 child_set_env(&env, &envsize,
1121 /* read $HOME/.ssh/environment. */
1122 if (options.permit_user_env) {
1123 snprintf(buf, sizeof buf, "%.200s/.ssh/environment",
1125 read_environment_file(&env, &envsize, buf,
1126 options.permit_user_env_whitelist);
1131 * Pull in any environment variables that may have
1134 if (options.use_pam) {
1138 * Don't allow PAM-internal env vars to leak
1139 * back into the session environment.
1141 #define PAM_ENV_BLACKLIST "SSH_AUTH_INFO*,SSH_CONNECTION*"
1142 p = fetch_pam_child_environment();
1143 copy_environment_blacklist(p, &env, &envsize,
1145 free_pam_environment(p);
1147 p = fetch_pam_environment();
1148 copy_environment_blacklist(p, &env, &envsize,
1150 free_pam_environment(p);
1152 #endif /* USE_PAM */
1154 /* Environment specified by admin */
1155 for (i = 0; i < options.num_setenv; i++) {
1156 cp = xstrdup(options.setenv[i]);
1157 if ((value = strchr(cp, '=')) == NULL) {
1158 /* shouldn't happen; vars are checked in servconf.c */
1159 fatal("Invalid config SetEnv: %s", options.setenv[i]);
1162 child_set_env(&env, &envsize, cp, value);
1165 /* SSH_CLIENT deprecated */
1166 snprintf(buf, sizeof buf, "%.50s %d %d",
1167 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1168 ssh_local_port(ssh));
1169 child_set_env(&env, &envsize, "SSH_CLIENT", buf);
1171 laddr = get_local_ipaddr(ssh_packet_get_connection_in(ssh));
1172 snprintf(buf, sizeof buf, "%.50s %d %.50s %d",
1173 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
1174 laddr, ssh_local_port(ssh));
1176 child_set_env(&env, &envsize, "SSH_CONNECTION", buf);
1178 if (tun_fwd_ifnames != NULL)
1179 child_set_env(&env, &envsize, "SSH_TUNNEL", tun_fwd_ifnames);
1180 if (auth_info_file != NULL)
1181 child_set_env(&env, &envsize, "SSH_USER_AUTH", auth_info_file);
1183 child_set_env(&env, &envsize, "SSH_TTY", s->tty);
1184 if (original_command)
1185 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND",
1189 /* dump the environment */
1190 fprintf(stderr, "Environment:\n");
1191 for (i = 0; env[i]; i++)
1192 fprintf(stderr, " %.200s\n", env[i]);
1198 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1199 * first in this order).
1202 do_rc_files(struct ssh *ssh, Session *s, const char *shell)
1210 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL;
1212 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1213 if (!s->is_subsystem && options.adm_forced_command == NULL &&
1214 auth_opts->permit_user_rc && options.permit_user_rc &&
1215 stat(_PATH_SSH_USER_RC, &st) >= 0) {
1216 snprintf(cmd, sizeof cmd, "%s -c '%s %s'",
1217 shell, _PATH_BSHELL, _PATH_SSH_USER_RC);
1219 fprintf(stderr, "Running %s\n", cmd);
1220 f = popen(cmd, "w");
1223 fprintf(f, "%s %s\n", s->auth_proto,
1227 fprintf(stderr, "Could not run %s\n",
1229 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) {
1231 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL,
1232 _PATH_SSH_SYSTEM_RC);
1233 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w");
1236 fprintf(f, "%s %s\n", s->auth_proto,
1240 fprintf(stderr, "Could not run %s\n",
1241 _PATH_SSH_SYSTEM_RC);
1242 } else if (do_xauth && options.xauth_location != NULL) {
1243 /* Add authority data to .Xauthority if appropriate. */
1246 "Running %.500s remove %.100s\n",
1247 options.xauth_location, s->auth_display);
1249 "%.500s add %.100s %.100s %.100s\n",
1250 options.xauth_location, s->auth_display,
1251 s->auth_proto, s->auth_data);
1253 snprintf(cmd, sizeof cmd, "%s -q -",
1254 options.xauth_location);
1255 f = popen(cmd, "w");
1257 fprintf(f, "remove %s\n",
1259 fprintf(f, "add %s %s %s\n",
1260 s->auth_display, s->auth_proto,
1264 fprintf(stderr, "Could not run %s\n",
1271 do_nologin(struct passwd *pw)
1274 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN;
1277 #ifdef HAVE_LOGIN_CAP
1278 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0)
1280 nl = login_getcapstr(lc, "nologin", def_nl, def_nl);
1282 if (pw->pw_uid == 0)
1286 if (stat(nl, &sb) == -1) {
1292 /* /etc/nologin exists. Print its contents if we can and exit. */
1293 logit("User %.100s not allowed because %s exists", pw->pw_name, nl);
1294 if ((f = fopen(nl, "r")) != NULL) {
1295 while (fgets(buf, sizeof(buf), f))
1303 * Chroot into a directory after checking it for safety: all path components
1304 * must be root-owned directories with strict permissions.
1307 safely_chroot(const char *path, uid_t uid)
1310 char component[PATH_MAX];
1313 if (!path_absolute(path))
1314 fatal("chroot path does not begin at root");
1315 if (strlen(path) >= sizeof(component))
1316 fatal("chroot path too long");
1319 * Descend the path, checking that each component is a
1320 * root-owned directory with strict permissions.
1322 for (cp = path; cp != NULL;) {
1323 if ((cp = strchr(cp, '/')) == NULL)
1324 strlcpy(component, path, sizeof(component));
1327 memcpy(component, path, cp - path);
1328 component[cp - path] = '\0';
1331 debug3("%s: checking '%s'", __func__, component);
1333 if (stat(component, &st) != 0)
1334 fatal("%s: stat(\"%s\"): %s", __func__,
1335 component, strerror(errno));
1336 if (st.st_uid != 0 || (st.st_mode & 022) != 0)
1337 fatal("bad ownership or modes for chroot "
1338 "directory %s\"%s\"",
1339 cp == NULL ? "" : "component ", component);
1340 if (!S_ISDIR(st.st_mode))
1341 fatal("chroot path %s\"%s\" is not a directory",
1342 cp == NULL ? "" : "component ", component);
1346 if (chdir(path) == -1)
1347 fatal("Unable to chdir to chroot path \"%s\": "
1348 "%s", path, strerror(errno));
1349 if (chroot(path) == -1)
1350 fatal("chroot(\"%s\"): %s", path, strerror(errno));
1351 if (chdir("/") == -1)
1352 fatal("%s: chdir(/) after chroot: %s",
1353 __func__, strerror(errno));
1354 verbose("Changed root directory to \"%s\"", path);
1357 /* Set login name, uid, gid, and groups. */
1359 do_setusercontext(struct passwd *pw)
1361 char uidstr[32], *chroot_path, *tmp;
1363 platform_setusercontext(pw);
1365 if (platform_privileged_uidswap()) {
1366 #ifdef HAVE_LOGIN_CAP
1367 if (setusercontext(lc, pw, pw->pw_uid,
1368 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) {
1369 perror("unable to set user context");
1373 if (setlogin(pw->pw_name) < 0)
1374 error("setlogin failed: %s", strerror(errno));
1375 if (setgid(pw->pw_gid) < 0) {
1379 /* Initialize the group list. */
1380 if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
1381 perror("initgroups");
1387 platform_setusercontext_post_groups(pw);
1389 if (!in_chroot && options.chroot_directory != NULL &&
1390 strcasecmp(options.chroot_directory, "none") != 0) {
1391 tmp = tilde_expand_filename(options.chroot_directory,
1393 snprintf(uidstr, sizeof(uidstr), "%llu",
1394 (unsigned long long)pw->pw_uid);
1395 chroot_path = percent_expand(tmp, "h", pw->pw_dir,
1396 "u", pw->pw_name, "U", uidstr, (char *)NULL);
1397 safely_chroot(chroot_path, pw->pw_uid);
1400 /* Make sure we don't attempt to chroot again */
1401 free(options.chroot_directory);
1402 options.chroot_directory = NULL;
1406 #ifdef HAVE_LOGIN_CAP
1407 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) {
1408 perror("unable to set user context (setuser)");
1412 * FreeBSD's setusercontext() will not apply the user's
1413 * own umask setting unless running with the user's UID.
1415 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK);
1419 * In a chroot environment, the set_id() will always fail;
1420 * typically because of the lack of necessary authentication
1421 * services and runtime such as ./usr/lib/libiaf.so,
1422 * ./usr/lib/libpam.so.1, and ./etc/passwd We skip it in the
1423 * internal sftp chroot case. We'll lose auditing and ACLs but
1424 * permanently_set_uid will take care of the rest.
1426 if (!in_chroot && set_id(pw->pw_name) != 0)
1427 fatal("set_id(%s) Failed", pw->pw_name);
1428 # endif /* USE_LIBIAF */
1429 /* Permanently switch to the desired uid. */
1430 permanently_set_uid(pw);
1432 } else if (options.chroot_directory != NULL &&
1433 strcasecmp(options.chroot_directory, "none") != 0) {
1434 fatal("server lacks privileges to chroot to ChrootDirectory");
1437 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
1438 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid);
1442 do_pwchange(Session *s)
1445 fprintf(stderr, "WARNING: Your password has expired.\n");
1446 if (s->ttyfd != -1) {
1448 "You must change your password now and login again!\n");
1452 #ifdef PASSWD_NEEDS_USERNAME
1453 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name,
1456 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL);
1461 "Password change required but no TTY available.\n");
1467 child_close_fds(struct ssh *ssh)
1469 extern int auth_sock;
1471 if (auth_sock != -1) {
1476 if (ssh_packet_get_connection_in(ssh) ==
1477 ssh_packet_get_connection_out(ssh))
1478 close(ssh_packet_get_connection_in(ssh));
1480 close(ssh_packet_get_connection_in(ssh));
1481 close(ssh_packet_get_connection_out(ssh));
1484 * Close all descriptors related to channels. They will still remain
1485 * open in the parent.
1487 /* XXX better use close-on-exec? -markus */
1488 channel_close_all(ssh);
1491 * Close any extra file descriptors. Note that there may still be
1492 * descriptors left by system functions. They will be closed later.
1497 * Close any extra open file descriptors so that we don't have them
1498 * hanging around in clients. Note that we want to do this after
1499 * initgroups, because at least on Solaris 2.3 it leaves file
1502 closefrom(STDERR_FILENO + 1);
1506 * Performs common processing for the child, such as setting up the
1507 * environment, closing extra file descriptors, setting the user and group
1508 * ids, and executing the command or shell.
1512 do_child(struct ssh *ssh, Session *s, const char *command)
1514 extern char **environ;
1515 char **env, *argv[ARGV_MAX], remote_id[512];
1516 const char *shell, *shell0;
1517 struct passwd *pw = s->pw;
1520 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
1522 /* remove hostkey from the child's memory */
1523 destroy_sensitive_data();
1524 ssh_packet_clear_keys(ssh);
1526 /* Force a password change */
1527 if (s->authctxt->force_pwchange) {
1528 do_setusercontext(pw);
1529 child_close_fds(ssh);
1535 * Login(1) does this as well, and it needs uid 0 for the "-h"
1536 * switch, so we let login(1) to this for us.
1539 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty);
1540 if (!check_quietlogin(s, command))
1542 #else /* HAVE_OSF_SIA */
1543 /* When PAM is enabled we rely on it to do the nologin check */
1544 if (!options.use_pam)
1546 do_setusercontext(pw);
1548 * PAM session modules in do_setusercontext may have
1549 * generated messages, so if this in an interactive
1550 * login then display them too.
1552 if (!check_quietlogin(s, command))
1554 #endif /* HAVE_OSF_SIA */
1557 if (options.use_pam && !is_pam_session_open()) {
1558 debug3("PAM session not opened, exiting");
1565 * Get the shell from the password data. An empty shell field is
1566 * legal, and means /bin/sh.
1568 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
1571 * Make sure $SHELL points to the shell from the password file,
1572 * even if shell is overridden from login.conf
1574 env = do_setup_env(ssh, s, shell);
1576 #ifdef HAVE_LOGIN_CAP
1577 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell);
1581 * Close the connection descriptors; note that this is the child, and
1582 * the server will still have the socket open, and it is important
1583 * that we do not shutdown it. Note that the descriptors cannot be
1584 * closed before building the environment, as we call
1585 * ssh_remote_ipaddr there.
1587 child_close_fds(ssh);
1590 * Must take new environment into use so that .ssh/rc,
1591 * /etc/ssh/sshrc and xauth are run in the proper environment.
1595 #if defined(KRB5) && defined(USE_AFS)
1597 * At this point, we check to see if AFS is active and if we have
1598 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1599 * if we can (and need to) extend the ticket into an AFS token. If
1600 * we don't do this, we run into potential problems if the user's
1601 * home directory is in AFS and it's not world-readable.
1604 if (options.kerberos_get_afs_token && k_hasafs() &&
1605 (s->authctxt->krb5_ctx != NULL)) {
1608 debug("Getting AFS token");
1612 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
1613 krb5_afslog(s->authctxt->krb5_ctx,
1614 s->authctxt->krb5_fwd_ccache, cell, NULL);
1616 krb5_afslog_home(s->authctxt->krb5_ctx,
1617 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir);
1621 /* Change current directory to the user's home directory. */
1622 if (chdir(pw->pw_dir) < 0) {
1623 /* Suppress missing homedir warning for chroot case */
1624 #ifdef HAVE_LOGIN_CAP
1625 r = login_getcapbool(lc, "requirehome", 0);
1627 if (r || !in_chroot) {
1628 fprintf(stderr, "Could not chdir to home "
1629 "directory %s: %s\n", pw->pw_dir,
1636 closefrom(STDERR_FILENO + 1);
1638 do_rc_files(ssh, s, shell);
1640 /* restore SIGPIPE for child */
1641 signal(SIGPIPE, SIG_DFL);
1643 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) {
1644 error("Connection from %s: refusing non-sftp session",
1646 printf("This service allows sftp connections only.\n");
1649 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) {
1650 extern int optind, optreset;
1654 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME);
1655 args = xstrdup(command ? command : "sftp-server");
1656 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " ")))
1657 if (i < ARGV_MAX - 1)
1660 optind = optreset = 1;
1661 __progname = argv[0];
1663 ssh_selinux_change_context("sftpd_t");
1665 exit(sftp_server_main(i, argv, s->pw));
1670 /* Get the last component of the shell name. */
1671 if ((shell0 = strrchr(shell, '/')) != NULL)
1677 * If we have no command, execute the shell. In this case, the shell
1678 * name to be passed in argv[0] is preceded by '-' to indicate that
1679 * this is a login shell.
1684 /* Start the shell. Set initial character to '-'. */
1687 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1)
1688 >= sizeof(argv0) - 1) {
1694 /* Execute the shell. */
1697 execve(shell, argv, env);
1699 /* Executing the shell failed. */
1704 * Execute the command using the user's shell. This uses the -c
1705 * option to execute the command.
1707 argv[0] = (char *) shell0;
1709 argv[2] = (char *) command;
1711 execve(shell, argv, env);
1717 session_unused(int id)
1719 debug3("%s: session id %d unused", __func__, id);
1720 if (id >= options.max_sessions ||
1721 id >= sessions_nalloc) {
1722 fatal("%s: insane session id %d (max %d nalloc %d)",
1723 __func__, id, options.max_sessions, sessions_nalloc);
1725 memset(&sessions[id], 0, sizeof(*sessions));
1726 sessions[id].self = id;
1727 sessions[id].used = 0;
1728 sessions[id].chanid = -1;
1729 sessions[id].ptyfd = -1;
1730 sessions[id].ttyfd = -1;
1731 sessions[id].ptymaster = -1;
1732 sessions[id].x11_chanids = NULL;
1733 sessions[id].next_unused = sessions_first_unused;
1734 sessions_first_unused = id;
1742 if (sessions_first_unused == -1) {
1743 if (sessions_nalloc >= options.max_sessions)
1745 debug2("%s: allocate (allocated %d max %d)",
1746 __func__, sessions_nalloc, options.max_sessions);
1747 tmp = xrecallocarray(sessions, sessions_nalloc,
1748 sessions_nalloc + 1, sizeof(*sessions));
1750 error("%s: cannot allocate %d sessions",
1751 __func__, sessions_nalloc + 1);
1755 session_unused(sessions_nalloc++);
1758 if (sessions_first_unused >= sessions_nalloc ||
1759 sessions_first_unused < 0) {
1760 fatal("%s: insane first_unused %d max %d nalloc %d",
1761 __func__, sessions_first_unused, options.max_sessions,
1765 s = &sessions[sessions_first_unused];
1767 fatal("%s: session %d already used",
1768 __func__, sessions_first_unused);
1770 sessions_first_unused = s->next_unused;
1772 s->next_unused = -1;
1773 debug("session_new: session %d", s->self);
1782 for (i = 0; i < sessions_nalloc; i++) {
1783 Session *s = &sessions[i];
1785 debug("dump: used %d next_unused %d session %d %p "
1786 "channel %d pid %ld",
1797 session_open(Authctxt *authctxt, int chanid)
1799 Session *s = session_new();
1800 debug("session_open: channel %d", chanid);
1802 error("no more sessions");
1805 s->authctxt = authctxt;
1806 s->pw = authctxt->pw;
1807 if (s->pw == NULL || !authctxt->valid)
1808 fatal("no user for session %d", s->self);
1809 debug("session_open: session %d: link with channel %d", s->self, chanid);
1815 session_by_tty(char *tty)
1818 for (i = 0; i < sessions_nalloc; i++) {
1819 Session *s = &sessions[i];
1820 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
1821 debug("session_by_tty: session %d tty %s", i, tty);
1825 debug("session_by_tty: unknown tty %.100s", tty);
1831 session_by_channel(int id)
1834 for (i = 0; i < sessions_nalloc; i++) {
1835 Session *s = &sessions[i];
1836 if (s->used && s->chanid == id) {
1837 debug("session_by_channel: session %d channel %d",
1842 debug("session_by_channel: unknown channel %d", id);
1848 session_by_x11_channel(int id)
1852 for (i = 0; i < sessions_nalloc; i++) {
1853 Session *s = &sessions[i];
1855 if (s->x11_chanids == NULL || !s->used)
1857 for (j = 0; s->x11_chanids[j] != -1; j++) {
1858 if (s->x11_chanids[j] == id) {
1859 debug("session_by_x11_channel: session %d "
1860 "channel %d", s->self, id);
1865 debug("session_by_x11_channel: unknown channel %d", id);
1871 session_by_pid(pid_t pid)
1874 debug("session_by_pid: pid %ld", (long)pid);
1875 for (i = 0; i < sessions_nalloc; i++) {
1876 Session *s = &sessions[i];
1877 if (s->used && s->pid == pid)
1880 error("session_by_pid: unknown pid %ld", (long)pid);
1886 session_window_change_req(struct ssh *ssh, Session *s)
1890 if ((r = sshpkt_get_u32(ssh, &s->col)) != 0 ||
1891 (r = sshpkt_get_u32(ssh, &s->row)) != 0 ||
1892 (r = sshpkt_get_u32(ssh, &s->xpixel)) != 0 ||
1893 (r = sshpkt_get_u32(ssh, &s->ypixel)) != 0 ||
1894 (r = sshpkt_get_end(ssh)) != 0)
1895 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
1896 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1901 session_pty_req(struct ssh *ssh, Session *s)
1905 if (!auth_opts->permit_pty_flag || !options.permit_tty) {
1906 debug("Allocating a pty not permitted for this connection.");
1909 if (s->ttyfd != -1) {
1910 ssh_packet_disconnect(ssh, "Protocol error: you already have a pty.");
1914 if ((r = sshpkt_get_cstring(ssh, &s->term, NULL)) != 0 ||
1915 (r = sshpkt_get_u32(ssh, &s->col)) != 0 ||
1916 (r = sshpkt_get_u32(ssh, &s->row)) != 0 ||
1917 (r = sshpkt_get_u32(ssh, &s->xpixel)) != 0 ||
1918 (r = sshpkt_get_u32(ssh, &s->ypixel)) != 0)
1919 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
1921 if (strcmp(s->term, "") == 0) {
1926 /* Allocate a pty and open it. */
1927 debug("Allocating pty.");
1928 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty,
1934 error("session_pty_req: session %d alloc failed", s->self);
1937 debug("session_pty_req: session %d alloc %s", s->self, s->tty);
1939 ssh_tty_parse_modes(ssh, s->ttyfd);
1941 if ((r = sshpkt_get_end(ssh)) != 0)
1942 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
1945 pty_setowner(s->pw, s->tty);
1947 /* Set window size from the packet. */
1948 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel);
1950 session_proctitle(s);
1955 session_subsystem_req(struct ssh *ssh, Session *s)
1962 if ((r = sshpkt_get_cstring(ssh, &s->subsys, NULL)) != 0 ||
1963 (r = sshpkt_get_end(ssh)) != 0)
1964 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
1965 debug2("subsystem request for %.100s by user %s", s->subsys,
1968 for (i = 0; i < options.num_subsystems; i++) {
1969 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) {
1970 prog = options.subsystem_command[i];
1971 cmd = options.subsystem_args[i];
1972 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) {
1973 s->is_subsystem = SUBSYSTEM_INT_SFTP;
1974 debug("subsystem: %s", prog);
1976 if (stat(prog, &st) < 0)
1977 debug("subsystem: cannot stat %s: %s",
1978 prog, strerror(errno));
1979 s->is_subsystem = SUBSYSTEM_EXT;
1980 debug("subsystem: exec() %s", cmd);
1982 success = do_exec(ssh, s, cmd) == 0;
1988 logit("subsystem request for %.100s by user %s failed, "
1989 "subsystem not found", s->subsys, s->pw->pw_name);
1995 session_x11_req(struct ssh *ssh, Session *s)
1998 u_char single_connection = 0;
2000 if (s->auth_proto != NULL || s->auth_data != NULL) {
2001 error("session_x11_req: session %d: "
2002 "x11 forwarding already active", s->self);
2005 if ((r = sshpkt_get_u8(ssh, &single_connection)) != 0 ||
2006 (r = sshpkt_get_cstring(ssh, &s->auth_proto, NULL)) != 0 ||
2007 (r = sshpkt_get_cstring(ssh, &s->auth_data, NULL)) != 0 ||
2008 (r = sshpkt_get_u32(ssh, &s->screen)) != 0 ||
2009 (r = sshpkt_get_end(ssh)) != 0)
2010 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
2012 s->single_connection = single_connection;
2014 if (xauth_valid_string(s->auth_proto) &&
2015 xauth_valid_string(s->auth_data))
2016 success = session_setup_x11fwd(ssh, s);
2019 error("Invalid X11 forwarding data");
2022 free(s->auth_proto);
2024 s->auth_proto = NULL;
2025 s->auth_data = NULL;
2031 session_shell_req(struct ssh *ssh, Session *s)
2035 if ((r = sshpkt_get_end(ssh)) != 0)
2036 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
2037 return do_exec(ssh, s, NULL) == 0;
2041 session_exec_req(struct ssh *ssh, Session *s)
2045 char *command = NULL;
2047 if ((r = sshpkt_get_cstring(ssh, &command, NULL)) != 0 ||
2048 (r = sshpkt_get_end(ssh)) != 0)
2049 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
2051 success = do_exec(ssh, s, command) == 0;
2057 session_break_req(struct ssh *ssh, Session *s)
2061 if ((r = sshpkt_get_u32(ssh, NULL)) != 0 || /* ignore */
2062 (r = sshpkt_get_end(ssh)) != 0)
2063 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
2065 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0)
2071 session_env_req(struct ssh *ssh, Session *s)
2077 if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0 ||
2078 (r = sshpkt_get_cstring(ssh, &val, NULL)) != 0 ||
2079 (r = sshpkt_get_end(ssh)) != 0)
2080 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
2082 /* Don't set too many environment variables */
2083 if (s->num_env > 128) {
2084 debug2("Ignoring env request %s: too many env vars", name);
2088 for (i = 0; i < options.num_accept_env; i++) {
2089 if (match_pattern(name, options.accept_env[i])) {
2090 debug2("Setting env %d: %s=%s", s->num_env, name, val);
2091 s->env = xrecallocarray(s->env, s->num_env,
2092 s->num_env + 1, sizeof(*s->env));
2093 s->env[s->num_env].name = name;
2094 s->env[s->num_env].val = val;
2099 debug2("Ignoring env request %s: disallowed name", name);
2108 * Conversion of signals from ssh channel request names.
2109 * Subset of signals from RFC 4254 section 6.10C, with SIGINFO as
2113 name2sig(char *name)
2115 #define SSH_SIG(x) if (strcmp(name, #x) == 0) return SIG ## x
2125 if (strcmp(name, "INFO@openssh.com") == 0)
2132 session_signal_req(struct ssh *ssh, Session *s)
2134 char *signame = NULL;
2135 int r, sig, success = 0;
2137 if ((r = sshpkt_get_cstring(ssh, &signame, NULL)) != 0 ||
2138 (r = sshpkt_get_end(ssh)) != 0) {
2139 error("%s: parse packet: %s", __func__, ssh_err(r));
2142 if ((sig = name2sig(signame)) == -1) {
2143 error("%s: unsupported signal \"%s\"", __func__, signame);
2147 error("%s: no pid for session %d", __func__, s->self);
2150 if (s->forced || s->is_subsystem) {
2151 error("%s: refusing to send signal %s to %s session", __func__,
2152 signame, s->forced ? "forced-command" : "subsystem");
2155 if (!use_privsep || mm_is_monitor()) {
2156 error("%s: session signalling requires privilege separation",
2161 debug("%s: signal %s, killpg(%ld, %d)", __func__, signame,
2163 temporarily_use_uid(s->pw);
2164 r = killpg(s->pid, sig);
2167 error("%s: killpg(%ld, %d): %s", __func__, (long)s->pid,
2168 sig, strerror(errno));
2180 session_auth_agent_req(struct ssh *ssh, Session *s)
2182 static int called = 0;
2185 if ((r = sshpkt_get_end(ssh)) != 0)
2186 sshpkt_fatal(ssh, r, "%s: parse packet", __func__);
2187 if (!auth_opts->permit_agent_forwarding_flag ||
2188 !options.allow_agent_forwarding) {
2189 debug("%s: agent forwarding disabled", __func__);
2196 return auth_input_request_forwarding(ssh, s->pw);
2201 session_input_channel_req(struct ssh *ssh, Channel *c, const char *rtype)
2206 if ((s = session_by_channel(c->self)) == NULL) {
2207 logit("%s: no session %d req %.100s", __func__, c->self, rtype);
2210 debug("%s: session %d req %s", __func__, s->self, rtype);
2213 * a session is in LARVAL state until a shell, a command
2214 * or a subsystem is executed
2216 if (c->type == SSH_CHANNEL_LARVAL) {
2217 if (strcmp(rtype, "shell") == 0) {
2218 success = session_shell_req(ssh, s);
2219 } else if (strcmp(rtype, "exec") == 0) {
2220 success = session_exec_req(ssh, s);
2221 } else if (strcmp(rtype, "pty-req") == 0) {
2222 success = session_pty_req(ssh, s);
2223 } else if (strcmp(rtype, "x11-req") == 0) {
2224 success = session_x11_req(ssh, s);
2225 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) {
2226 success = session_auth_agent_req(ssh, s);
2227 } else if (strcmp(rtype, "subsystem") == 0) {
2228 success = session_subsystem_req(ssh, s);
2229 } else if (strcmp(rtype, "env") == 0) {
2230 success = session_env_req(ssh, s);
2233 if (strcmp(rtype, "window-change") == 0) {
2234 success = session_window_change_req(ssh, s);
2235 } else if (strcmp(rtype, "break") == 0) {
2236 success = session_break_req(ssh, s);
2237 } else if (strcmp(rtype, "signal") == 0) {
2238 success = session_signal_req(ssh, s);
2245 session_set_fds(struct ssh *ssh, Session *s,
2246 int fdin, int fdout, int fderr, int ignore_fderr, int is_tty)
2249 * now that have a child and a pipe to the child,
2250 * we can activate our channel and register the fd's
2252 if (s->chanid == -1)
2253 fatal("no channel for session %d", s->self);
2254 channel_set_fds(ssh, s->chanid,
2256 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ,
2257 1, is_tty, CHAN_SES_WINDOW_DEFAULT);
2261 * Function to perform pty cleanup. Also called if we get aborted abnormally
2262 * (e.g., due to a dropped connection).
2265 session_pty_cleanup2(Session *s)
2268 error("%s: no session", __func__);
2274 debug("%s: session %d release %s", __func__, s->self, s->tty);
2276 /* Record that the user has logged out. */
2278 record_logout(s->pid, s->tty, s->pw->pw_name);
2280 /* Release the pseudo-tty. */
2282 pty_release(s->tty);
2285 * Close the server side of the socket pairs. We must do this after
2286 * the pty cleanup, so that another process doesn't get this pty
2287 * while we're still cleaning up.
2289 if (s->ptymaster != -1 && close(s->ptymaster) < 0)
2290 error("close(s->ptymaster/%d): %s",
2291 s->ptymaster, strerror(errno));
2293 /* unlink pty from session */
2298 session_pty_cleanup(Session *s)
2300 PRIVSEP(session_pty_cleanup2(s));
2306 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2321 return "SIG@openssh.com";
2325 session_close_x11(struct ssh *ssh, int id)
2329 if ((c = channel_by_id(ssh, id)) == NULL) {
2330 debug("%s: x11 channel %d missing", __func__, id);
2332 /* Detach X11 listener */
2333 debug("%s: detach x11 channel %d", __func__, id);
2334 channel_cancel_cleanup(ssh, id);
2335 if (c->ostate != CHAN_OUTPUT_CLOSED)
2336 chan_mark_dead(ssh, c);
2341 session_close_single_x11(struct ssh *ssh, int id, void *arg)
2346 debug3("%s: channel %d", __func__, id);
2347 channel_cancel_cleanup(ssh, id);
2348 if ((s = session_by_x11_channel(id)) == NULL)
2349 fatal("%s: no x11 channel %d", __func__, id);
2350 for (i = 0; s->x11_chanids[i] != -1; i++) {
2351 debug("%s: session %d: closing channel %d",
2352 __func__, s->self, s->x11_chanids[i]);
2354 * The channel "id" is already closing, but make sure we
2355 * close all of its siblings.
2357 if (s->x11_chanids[i] != id)
2358 session_close_x11(ssh, s->x11_chanids[i]);
2360 free(s->x11_chanids);
2361 s->x11_chanids = NULL;
2364 free(s->auth_proto);
2365 s->auth_proto = NULL;
2367 s->auth_data = NULL;
2368 free(s->auth_display);
2369 s->auth_display = NULL;
2373 session_exit_message(struct ssh *ssh, Session *s, int status)
2378 if ((c = channel_lookup(ssh, s->chanid)) == NULL)
2379 fatal("%s: session %d: no channel %d",
2380 __func__, s->self, s->chanid);
2381 debug("%s: session %d channel %d pid %ld",
2382 __func__, s->self, s->chanid, (long)s->pid);
2384 if (WIFEXITED(status)) {
2385 channel_request_start(ssh, s->chanid, "exit-status", 0);
2386 if ((r = sshpkt_put_u32(ssh, WEXITSTATUS(status))) != 0 ||
2387 (r = sshpkt_send(ssh)) != 0)
2388 sshpkt_fatal(ssh, r, "%s: exit reply", __func__);
2389 } else if (WIFSIGNALED(status)) {
2390 channel_request_start(ssh, s->chanid, "exit-signal", 0);
2392 # define WCOREDUMP(x) (0)
2394 if ((r = sshpkt_put_cstring(ssh, sig2name(WTERMSIG(status)))) != 0 ||
2395 (r = sshpkt_put_u8(ssh, WCOREDUMP(status)? 1 : 0)) != 0 ||
2396 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2397 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
2398 (r = sshpkt_send(ssh)) != 0)
2399 sshpkt_fatal(ssh, r, "%s: exit reply", __func__);
2401 /* Some weird exit cause. Just exit. */
2402 ssh_packet_disconnect(ssh, "wait returned status %04x.", status);
2405 /* disconnect channel */
2406 debug("%s: release channel %d", __func__, s->chanid);
2409 * Adjust cleanup callback attachment to send close messages when
2410 * the channel gets EOF. The session will be then be closed
2411 * by session_close_by_channel when the childs close their fds.
2413 channel_register_cleanup(ssh, c->self, session_close_by_channel, 1);
2416 * emulate a write failure with 'chan_write_failed', nobody will be
2417 * interested in data we write.
2418 * Note that we must not call 'chan_read_failed', since there could
2419 * be some more data waiting in the pipe.
2421 if (c->ostate != CHAN_OUTPUT_CLOSED)
2422 chan_write_failed(ssh, c);
2426 session_close(struct ssh *ssh, Session *s)
2430 verbose("Close session: user %s from %.200s port %d id %d",
2432 ssh_remote_ipaddr(ssh),
2433 ssh_remote_port(ssh),
2437 session_pty_cleanup(s);
2440 free(s->x11_chanids);
2441 free(s->auth_display);
2443 free(s->auth_proto);
2445 if (s->env != NULL) {
2446 for (i = 0; i < s->num_env; i++) {
2447 free(s->env[i].name);
2448 free(s->env[i].val);
2452 session_proctitle(s);
2453 session_unused(s->self);
2457 session_close_by_pid(struct ssh *ssh, pid_t pid, int status)
2459 Session *s = session_by_pid(pid);
2461 debug("%s: no session for pid %ld", __func__, (long)pid);
2464 if (s->chanid != -1)
2465 session_exit_message(ssh, s, status);
2467 session_pty_cleanup(s);
2472 * this is called when a channel dies before
2473 * the session 'child' itself dies
2476 session_close_by_channel(struct ssh *ssh, int id, void *arg)
2478 Session *s = session_by_channel(id);
2482 debug("%s: no session for id %d", __func__, id);
2485 debug("%s: channel %d child %ld", __func__, id, (long)s->pid);
2487 debug("%s: channel %d: has child, ttyfd %d",
2488 __func__, id, s->ttyfd);
2490 * delay detach of session, but release pty, since
2491 * the fd's to the child are already closed
2494 session_pty_cleanup(s);
2497 /* detach by removing callback */
2498 channel_cancel_cleanup(ssh, s->chanid);
2500 /* Close any X11 listeners associated with this session */
2501 if (s->x11_chanids != NULL) {
2502 for (i = 0; s->x11_chanids[i] != -1; i++) {
2503 session_close_x11(ssh, s->x11_chanids[i]);
2504 s->x11_chanids[i] = -1;
2509 session_close(ssh, s);
2513 session_destroy_all(struct ssh *ssh, void (*closefunc)(Session *))
2516 for (i = 0; i < sessions_nalloc; i++) {
2517 Session *s = &sessions[i];
2519 if (closefunc != NULL)
2522 session_close(ssh, s);
2528 session_tty_list(void)
2530 static char buf[1024];
2535 for (i = 0; i < sessions_nalloc; i++) {
2536 Session *s = &sessions[i];
2537 if (s->used && s->ttyfd != -1) {
2539 if (strncmp(s->tty, "/dev/", 5) != 0) {
2540 cp = strrchr(s->tty, '/');
2541 cp = (cp == NULL) ? s->tty : cp + 1;
2546 strlcat(buf, ",", sizeof buf);
2547 strlcat(buf, cp, sizeof buf);
2551 strlcpy(buf, "notty", sizeof buf);
2556 session_proctitle(Session *s)
2559 error("no user for session %d", s->self);
2561 setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
2565 session_setup_x11fwd(struct ssh *ssh, Session *s)
2568 char display[512], auth_display[512];
2569 char hostname[NI_MAXHOST];
2572 if (!auth_opts->permit_x11_forwarding_flag) {
2573 ssh_packet_send_debug(ssh, "X11 forwarding disabled by key options.");
2576 if (!options.x11_forwarding) {
2577 debug("X11 forwarding disabled in server configuration file.");
2580 if (options.xauth_location == NULL ||
2581 (stat(options.xauth_location, &st) == -1)) {
2582 ssh_packet_send_debug(ssh, "No xauth program; cannot forward X11.");
2585 if (s->display != NULL) {
2586 debug("X11 display already set.");
2589 if (x11_create_display_inet(ssh, options.x11_display_offset,
2590 options.x11_use_localhost, s->single_connection,
2591 &s->display_number, &s->x11_chanids) == -1) {
2592 debug("x11_create_display_inet failed.");
2595 for (i = 0; s->x11_chanids[i] != -1; i++) {
2596 channel_register_cleanup(ssh, s->x11_chanids[i],
2597 session_close_single_x11, 0);
2600 /* Set up a suitable value for the DISPLAY variable. */
2601 if (gethostname(hostname, sizeof(hostname)) < 0)
2602 fatal("gethostname: %.100s", strerror(errno));
2604 * auth_display must be used as the displayname when the
2605 * authorization entry is added with xauth(1). This will be
2606 * different than the DISPLAY string for localhost displays.
2608 if (options.x11_use_localhost) {
2609 snprintf(display, sizeof display, "localhost:%u.%u",
2610 s->display_number, s->screen);
2611 snprintf(auth_display, sizeof auth_display, "unix:%u.%u",
2612 s->display_number, s->screen);
2613 s->display = xstrdup(display);
2614 s->auth_display = xstrdup(auth_display);
2616 #ifdef IPADDR_IN_DISPLAY
2618 struct in_addr my_addr;
2620 he = gethostbyname(hostname);
2622 error("Can't get IP address for X11 DISPLAY.");
2623 ssh_packet_send_debug(ssh, "Can't get IP address for X11 DISPLAY.");
2626 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr));
2627 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr),
2628 s->display_number, s->screen);
2630 snprintf(display, sizeof display, "%.400s:%u.%u", hostname,
2631 s->display_number, s->screen);
2633 s->display = xstrdup(display);
2634 s->auth_display = xstrdup(display);
2641 do_authenticated2(struct ssh *ssh, Authctxt *authctxt)
2643 server_loop2(ssh, authctxt);
2647 do_cleanup(struct ssh *ssh, Authctxt *authctxt)
2649 static int called = 0;
2651 debug("do_cleanup");
2653 /* no cleanup if we're in the child for login shell */
2657 /* avoid double cleanup */
2662 if (authctxt == NULL)
2666 if (options.use_pam) {
2668 sshpam_thread_cleanup();
2672 if (!authctxt->authenticated)
2676 if (options.kerberos_ticket_cleanup &&
2678 krb5_cleanup_proc(authctxt);
2682 if (options.gss_cleanup_creds)
2683 ssh_gssapi_cleanup_creds();
2686 /* remove agent socket */
2687 auth_sock_cleanup_proc(authctxt->pw);
2689 /* remove userauth info */
2690 if (auth_info_file != NULL) {
2691 temporarily_use_uid(authctxt->pw);
2692 unlink(auth_info_file);
2694 free(auth_info_file);
2695 auth_info_file = NULL;
2699 * Cleanup ptys/utmp only if privsep is disabled,
2700 * or if running in monitor.
2702 if (!use_privsep || mm_is_monitor())
2703 session_destroy_all(ssh, session_pty_cleanup2);
2706 /* Return a name for the remote host that fits inside utmp_size */
2709 session_get_remote_name_or_ip(struct ssh *ssh, u_int utmp_size, int use_dns)
2711 const char *remote = "";
2714 remote = auth_get_canonical_hostname(ssh, use_dns);
2715 if (utmp_size == 0 || strlen(remote) > utmp_size)
2716 remote = ssh_remote_ipaddr(ssh);