1 /* $OpenBSD: session.c,v 1.246 2009/04/17 19:23:06 stevesk 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>
62 #include "openbsd-compat/sys-queue.h"
81 #include "auth-options.h"
82 #include "pathnames.h"
86 #include "serverloop.h"
91 #include "monitor_wrap.h"
94 #if defined(KRB5) && defined(USE_AFS)
98 #define IS_INTERNAL_SFTP(c) \
99 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \
100 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \
101 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \
102 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t'))
106 Session
*session_new(void);
107 void session_set_fds(Session
*, int, int, int, int);
108 void session_pty_cleanup(Session
*);
109 void session_proctitle(Session
*);
110 int session_setup_x11fwd(Session
*);
111 int do_exec_pty(Session
*, const char *);
112 int do_exec_no_pty(Session
*, const char *);
113 int do_exec(Session
*, const char *);
114 void do_login(Session
*, const char *);
115 #ifdef LOGIN_NEEDS_UTMPX
116 static void do_pre_login(Session
*s
);
118 void do_child(Session
*, const char *);
120 int check_quietlogin(Session
*, const char *);
122 static void do_authenticated1(Authctxt
*);
123 static void do_authenticated2(Authctxt
*);
125 static int session_pty_req(Session
*);
128 extern ServerOptions options
;
129 extern char *__progname
;
130 extern int log_stderr
;
131 extern int debug_flag
;
132 extern u_int utmp_len
;
133 extern int startup_pipe
;
134 extern void destroy_sensitive_data(void);
135 extern Buffer loginmsg
;
137 /* original command from peer. */
138 const char *original_command
= NULL
;
141 static int sessions_first_unused
= -1;
142 static int sessions_nalloc
= 0;
143 static Session
*sessions
= NULL
;
145 #define SUBSYSTEM_NONE 0
146 #define SUBSYSTEM_EXT 1
147 #define SUBSYSTEM_INT_SFTP 2
149 #ifdef HAVE_LOGIN_CAP
153 static int is_child
= 0;
155 /* Name and directory of socket for authentication agent forwarding. */
156 static char *auth_sock_name
= NULL
;
157 static char *auth_sock_dir
= NULL
;
159 /* removes the agent forwarding socket */
162 auth_sock_cleanup_proc(struct passwd
*pw
)
164 if (auth_sock_name
!= NULL
) {
165 temporarily_use_uid(pw
);
166 unlink(auth_sock_name
);
167 rmdir(auth_sock_dir
);
168 auth_sock_name
= NULL
;
174 auth_input_request_forwarding(struct passwd
* pw
)
178 struct sockaddr_un sunaddr
;
180 if (auth_sock_name
!= NULL
) {
181 error("authentication forwarding requested twice.");
185 /* Temporarily drop privileged uid for mkdir/bind. */
186 temporarily_use_uid(pw
);
188 /* Allocate a buffer for the socket name, and format the name. */
189 auth_sock_dir
= xstrdup("/tmp/ssh-XXXXXXXXXX");
191 /* Create private directory for socket */
192 if (mkdtemp(auth_sock_dir
) == NULL
) {
193 packet_send_debug("Agent forwarding disabled: "
194 "mkdtemp() failed: %.100s", strerror(errno
));
196 xfree(auth_sock_dir
);
197 auth_sock_dir
= NULL
;
201 xasprintf(&auth_sock_name
, "%s/agent.%ld",
202 auth_sock_dir
, (long) getpid());
204 /* Create the socket. */
205 sock
= socket(AF_UNIX
, SOCK_STREAM
, 0);
207 error("socket: %.100s", strerror(errno
));
212 /* Bind it to the name. */
213 memset(&sunaddr
, 0, sizeof(sunaddr
));
214 sunaddr
.sun_family
= AF_UNIX
;
215 strlcpy(sunaddr
.sun_path
, auth_sock_name
, sizeof(sunaddr
.sun_path
));
217 if (bind(sock
, (struct sockaddr
*)&sunaddr
, sizeof(sunaddr
)) < 0) {
218 error("bind: %.100s", strerror(errno
));
223 /* Restore the privileged uid. */
226 /* Start listening on the socket. */
227 if (listen(sock
, SSH_LISTEN_BACKLOG
) < 0) {
228 error("listen: %.100s", strerror(errno
));
232 /* Allocate a channel for the authentication agent socket. */
233 /* this shouldn't matter if its hpn or not - cjr */
234 nc
= channel_new("auth socket",
235 SSH_CHANNEL_AUTH_SOCKET
, sock
, sock
, -1,
236 CHAN_X11_WINDOW_DEFAULT
, CHAN_X11_PACKET_DEFAULT
,
237 0, "auth socket", 1);
238 nc
->path
= xstrdup(auth_sock_name
);
242 if (auth_sock_name
!= NULL
)
243 xfree(auth_sock_name
);
244 if (auth_sock_dir
!= NULL
) {
245 rmdir(auth_sock_dir
);
246 xfree(auth_sock_dir
);
250 auth_sock_name
= NULL
;
251 auth_sock_dir
= NULL
;
256 display_loginmsg(void)
258 if (buffer_len(&loginmsg
) > 0) {
259 buffer_append(&loginmsg
, "\0", 1);
260 printf("%s", (char *)buffer_ptr(&loginmsg
));
261 buffer_clear(&loginmsg
);
266 do_authenticated(Authctxt
*authctxt
)
268 setproctitle("%s", authctxt
->pw
->pw_name
);
270 /* setup the channel layer */
271 if (!no_port_forwarding_flag
&& options
.allow_tcp_forwarding
)
272 channel_permit_all_opens();
275 do_authenticated2(authctxt
);
277 do_authenticated1(authctxt
);
279 do_cleanup(authctxt
);
283 * Prepares for an interactive session. This is called after the user has
284 * been successfully authenticated. During this message exchange, pseudo
285 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings
286 * are requested, etc.
289 do_authenticated1(Authctxt
*authctxt
)
293 int success
, type
, screen_flag
;
294 int enable_compression_after_reply
= 0;
295 u_int proto_len
, data_len
, dlen
, compression_level
= 0;
299 error("no more sessions");
302 s
->authctxt
= authctxt
;
303 s
->pw
= authctxt
->pw
;
306 * We stay in this loop until the client requests to execute a shell
312 /* Get a packet from the client. */
313 type
= packet_read();
315 /* Process the packet. */
317 case SSH_CMSG_REQUEST_COMPRESSION
:
318 compression_level
= packet_get_int();
320 if (compression_level
< 1 || compression_level
> 9) {
321 packet_send_debug("Received invalid compression level %d.",
325 if (options
.compression
== COMP_NONE
) {
326 debug2("compression disabled");
329 /* Enable compression after we have responded with SUCCESS. */
330 enable_compression_after_reply
= 1;
334 case SSH_CMSG_REQUEST_PTY
:
335 success
= session_pty_req(s
);
338 case SSH_CMSG_X11_REQUEST_FORWARDING
:
339 s
->auth_proto
= packet_get_string(&proto_len
);
340 s
->auth_data
= packet_get_string(&data_len
);
342 screen_flag
= packet_get_protocol_flags() &
343 SSH_PROTOFLAG_SCREEN_NUMBER
;
344 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag
);
346 if (packet_remaining() == 4) {
348 debug2("Buggy client: "
349 "X11 screen flag missing");
350 s
->screen
= packet_get_int();
355 success
= session_setup_x11fwd(s
);
357 xfree(s
->auth_proto
);
359 s
->auth_proto
= NULL
;
364 case SSH_CMSG_AGENT_REQUEST_FORWARDING
:
365 if (!options
.allow_agent_forwarding
||
366 no_agent_forwarding_flag
|| compat13
) {
367 debug("Authentication agent forwarding not permitted for this authentication.");
370 debug("Received authentication agent forwarding request.");
371 success
= auth_input_request_forwarding(s
->pw
);
374 case SSH_CMSG_PORT_FORWARD_REQUEST
:
375 if (no_port_forwarding_flag
) {
376 debug("Port forwarding not permitted for this authentication.");
379 if (!options
.allow_tcp_forwarding
) {
380 debug("Port forwarding not permitted.");
383 debug("Received TCP/IP port forwarding request.");
384 if (channel_input_port_forward_request(s
->pw
->pw_uid
== 0,
385 options
.gateway_ports
) < 0) {
386 debug("Port forwarding failed.");
392 case SSH_CMSG_MAX_PACKET_SIZE
:
393 if (packet_set_maxsize(packet_get_int()) > 0)
397 case SSH_CMSG_EXEC_SHELL
:
398 case SSH_CMSG_EXEC_CMD
:
399 if (type
== SSH_CMSG_EXEC_CMD
) {
400 command
= packet_get_string(&dlen
);
401 debug("Exec command '%.500s'", command
);
402 if (do_exec(s
, command
) != 0)
404 "command execution failed");
407 if (do_exec(s
, NULL
) != 0)
409 "shell execution failed");
417 * Any unknown messages in this phase are ignored,
418 * and a failure message is returned.
420 logit("Unknown packet type received after authentication: %d", type
);
422 packet_start(success
? SSH_SMSG_SUCCESS
: SSH_SMSG_FAILURE
);
426 /* Enable compression now that we have replied if appropriate. */
427 if (enable_compression_after_reply
) {
428 enable_compression_after_reply
= 0;
429 packet_start_compression(compression_level
);
436 * This is called to fork and execute a command when we have no tty. This
437 * will call do_child from the child, and server_loop from the parent after
438 * setting up file descriptors and such.
441 do_exec_no_pty(Session
*s
, const char *command
)
446 int pin
[2], pout
[2], perr
[2];
448 /* Allocate pipes for communicating with the program. */
450 error("%s: pipe in: %.100s", __func__
, strerror(errno
));
453 if (pipe(pout
) < 0) {
454 error("%s: pipe out: %.100s", __func__
, strerror(errno
));
459 if (pipe(perr
) < 0) {
460 error("%s: pipe err: %.100s", __func__
, strerror(errno
));
468 int inout
[2], err
[2];
470 /* Uses socket pairs to communicate with the program. */
471 if (socketpair(AF_UNIX
, SOCK_STREAM
, 0, inout
) < 0) {
472 error("%s: socketpair #1: %.100s", __func__
, strerror(errno
));
475 if (socketpair(AF_UNIX
, SOCK_STREAM
, 0, err
) < 0) {
476 error("%s: socketpair #2: %.100s", __func__
, strerror(errno
));
484 fatal("do_exec_no_pty: no session");
486 session_proctitle(s
);
488 /* Fork the child. */
489 switch ((pid
= fork())) {
491 error("%s: fork: %.100s", __func__
, strerror(errno
));
509 /* Child. Reinitialize the log since the pid has changed. */
510 log_init(__progname
, options
.log_level
,
511 options
.log_facility
, log_stderr
);
514 * Create a new session and process group since the 4.4BSD
515 * setlogin() affects the entire process group.
518 error("setsid failed: %.100s", strerror(errno
));
522 * Redirect stdin. We close the parent side of the socket
523 * pair, and make the child side the standard input.
526 if (dup2(pin
[0], 0) < 0)
527 perror("dup2 stdin");
530 /* Redirect stdout. */
532 if (dup2(pout
[1], 1) < 0)
533 perror("dup2 stdout");
536 /* Redirect stderr. */
538 if (dup2(perr
[1], 2) < 0)
539 perror("dup2 stderr");
543 * Redirect stdin, stdout, and stderr. Stdin and stdout will
544 * use the same socket, as some programs (particularly rdist)
545 * seem to depend on it.
549 if (dup2(inout
[0], 0) < 0) /* stdin */
550 perror("dup2 stdin");
551 if (dup2(inout
[0], 1) < 0) /* stdout (same as stdin) */
552 perror("dup2 stdout");
554 if (dup2(err
[0], 2) < 0) /* stderr */
555 perror("dup2 stderr");
561 cray_init_job(s
->pw
); /* set up cray jid and tmpdir */
564 /* Do processing for the child (exec command etc). */
565 do_child(s
, command
);
572 signal(WJSIGNAL
, cray_job_termination_handler
);
575 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE
);
579 /* Set interactive/non-interactive mode. */
580 packet_set_interactive(s
->display
!= NULL
);
583 * Clear loginmsg, since it's the child's responsibility to display
584 * it to the user, otherwise multiple sessions may accumulate
585 * multiple copies of the login messages.
587 buffer_clear(&loginmsg
);
590 /* We are the parent. Close the child sides of the pipes. */
596 if (s
->is_subsystem
) {
600 session_set_fds(s
, pin
[1], pout
[0], perr
[0], 0);
602 /* Enter the interactive session. */
603 server_loop(pid
, pin
[1], pout
[0], perr
[0]);
604 /* server_loop has closed pin[1], pout[0], and perr[0]. */
607 /* We are the parent. Close the child sides of the socket pairs. */
612 * Enter the interactive session. Note: server_loop must be able to
613 * handle the case that fdin and fdout are the same.
616 session_set_fds(s
, inout
[1], inout
[1],
617 s
->is_subsystem
? -1 : err
[1], 0);
621 server_loop(pid
, inout
[1], inout
[1], err
[1]);
622 /* server_loop has closed inout[1] and err[1]. */
629 * This is called to fork and execute a command when we have a tty. This
630 * will call do_child from the child, and server_loop from the parent after
631 * setting up file descriptors, controlling tty, updating wtmp, utmp,
632 * lastlog, and other such operations.
635 do_exec_pty(Session
*s
, const char *command
)
637 int fdout
, ptyfd
, ttyfd
, ptymaster
;
641 fatal("do_exec_pty: no session");
646 * Create another descriptor of the pty master side for use as the
647 * standard input. We could use the original descriptor, but this
648 * simplifies code in server_loop. The descriptor is bidirectional.
649 * Do this before forking (and cleanup in the child) so as to
650 * detect and gracefully fail out-of-fd conditions.
652 if ((fdout
= dup(ptyfd
)) < 0) {
653 error("%s: dup #1: %s", __func__
, strerror(errno
));
658 /* we keep a reference to the pty master */
659 if ((ptymaster
= dup(ptyfd
)) < 0) {
660 error("%s: dup #2: %s", __func__
, strerror(errno
));
667 /* Fork the child. */
668 switch ((pid
= fork())) {
670 error("%s: fork: %.100s", __func__
, strerror(errno
));
682 /* Child. Reinitialize the log because the pid has changed. */
683 log_init(__progname
, options
.log_level
,
684 options
.log_facility
, log_stderr
);
685 /* Close the master side of the pseudo tty. */
688 /* Make the pseudo tty our controlling tty. */
689 pty_make_controlling_tty(&ttyfd
, s
->tty
);
691 /* Redirect stdin/stdout/stderr from the pseudo tty. */
692 if (dup2(ttyfd
, 0) < 0)
693 error("dup2 stdin: %s", strerror(errno
));
694 if (dup2(ttyfd
, 1) < 0)
695 error("dup2 stdout: %s", strerror(errno
));
696 if (dup2(ttyfd
, 2) < 0)
697 error("dup2 stderr: %s", strerror(errno
));
699 /* Close the extra descriptor for the pseudo tty. */
702 /* record login, etc. similar to login(1) */
704 if (!(options
.use_login
&& command
== NULL
)) {
706 cray_init_job(s
->pw
); /* set up cray jid and tmpdir */
708 do_login(s
, command
);
710 # ifdef LOGIN_NEEDS_UTMPX
716 * Do common processing for the child, such as execing
719 do_child(s
, command
);
726 signal(WJSIGNAL
, cray_job_termination_handler
);
729 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE
);
734 /* Parent. Close the slave side of the pseudo tty. */
737 /* Enter interactive session. */
738 s
->ptymaster
= ptymaster
;
739 packet_set_interactive(1);
741 session_set_fds(s
, ptyfd
, fdout
, -1, 1);
743 server_loop(pid
, ptyfd
, fdout
, -1);
744 /* server_loop _has_ closed ptyfd and fdout. */
749 #ifdef LOGIN_NEEDS_UTMPX
751 do_pre_login(Session
*s
)
754 struct sockaddr_storage from
;
755 pid_t pid
= getpid();
758 * Get IP address of client. If the connection is not a socket, let
759 * the address be 0.0.0.0.
761 memset(&from
, 0, sizeof(from
));
762 fromlen
= sizeof(from
);
763 if (packet_connection_is_on_socket()) {
764 if (getpeername(packet_get_connection_in(),
765 (struct sockaddr
*)&from
, &fromlen
) < 0) {
766 debug("getpeername: %.100s", strerror(errno
));
771 record_utmp_only(pid
, s
->tty
, s
->pw
->pw_name
,
772 get_remote_name_or_ip(utmp_len
, options
.use_dns
),
773 (struct sockaddr
*)&from
, fromlen
);
778 * This is called to fork and execute a command. If another command is
779 * to be forced, execute that instead.
782 do_exec(Session
*s
, const char *command
)
786 if (options
.adm_forced_command
) {
787 original_command
= command
;
788 command
= options
.adm_forced_command
;
789 if (IS_INTERNAL_SFTP(command
))
790 s
->is_subsystem
= SUBSYSTEM_INT_SFTP
;
791 else if (s
->is_subsystem
)
792 s
->is_subsystem
= SUBSYSTEM_EXT
;
793 debug("Forced command (config) '%.900s'", command
);
794 } else if (forced_command
) {
795 original_command
= command
;
796 command
= forced_command
;
797 if (IS_INTERNAL_SFTP(command
))
798 s
->is_subsystem
= SUBSYSTEM_INT_SFTP
;
799 else if (s
->is_subsystem
)
800 s
->is_subsystem
= SUBSYSTEM_EXT
;
801 debug("Forced command (key option) '%.900s'", command
);
804 #ifdef SSH_AUDIT_EVENTS
806 PRIVSEP(audit_run_command(command
));
807 else if (s
->ttyfd
== -1) {
808 char *shell
= s
->pw
->pw_shell
;
810 if (shell
[0] == '\0') /* empty shell means /bin/sh */
812 PRIVSEP(audit_run_command(shell
));
816 ret
= do_exec_pty(s
, command
);
818 ret
= do_exec_no_pty(s
, command
);
820 original_command
= NULL
;
823 * Clear loginmsg: it's the child's responsibility to display
824 * it to the user, otherwise multiple sessions may accumulate
825 * multiple copies of the login messages.
827 buffer_clear(&loginmsg
);
832 /* administrative, login(1)-like work */
834 do_login(Session
*s
, const char *command
)
837 struct sockaddr_storage from
;
838 struct passwd
* pw
= s
->pw
;
839 pid_t pid
= getpid();
842 * Get IP address of client. If the connection is not a socket, let
843 * the address be 0.0.0.0.
845 memset(&from
, 0, sizeof(from
));
846 fromlen
= sizeof(from
);
847 if (packet_connection_is_on_socket()) {
848 if (getpeername(packet_get_connection_in(),
849 (struct sockaddr
*)&from
, &fromlen
) < 0) {
850 debug("getpeername: %.100s", strerror(errno
));
855 /* Record that there was a login on that tty from the remote host. */
857 record_login(pid
, s
->tty
, pw
->pw_name
, pw
->pw_uid
,
858 get_remote_name_or_ip(utmp_len
,
860 (struct sockaddr
*)&from
, fromlen
);
864 * If password change is needed, do it now.
865 * This needs to occur before the ~/.hushlogin check.
867 if (options
.use_pam
&& !use_privsep
&& s
->authctxt
->force_pwchange
) {
870 s
->authctxt
->force_pwchange
= 0;
871 /* XXX - signal [net] parent to enable forwardings */
875 if (check_quietlogin(s
, command
))
884 * Display the message of the day.
891 #ifdef HAVE_LOGIN_CAP
895 #ifdef HAVE_LOGIN_CAP
896 fname
= login_getcapstr(lc
, "copyright", NULL
, NULL
);
897 if (fname
!= NULL
&& (f
= fopen(fname
, "r")) != NULL
) {
898 while (fgets(buf
, sizeof(buf
), f
) != NULL
)
902 #endif /* HAVE_LOGIN_CAP */
903 (void)printf("%s\n\t%s %s\n",
904 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
905 "The Regents of the University of California. ",
906 "All rights reserved.");
910 if (options
.print_motd
) {
911 #ifdef HAVE_LOGIN_CAP
912 f
= fopen(login_getcapstr(lc
, "welcome", "/etc/motd",
915 f
= fopen("/etc/motd", "r");
918 while (fgets(buf
, sizeof(buf
), f
))
927 * Check for quiet login, either .hushlogin or command given.
930 check_quietlogin(Session
*s
, const char *command
)
933 struct passwd
*pw
= s
->pw
;
936 /* Return 1 if .hushlogin exists or a command given. */
939 snprintf(buf
, sizeof(buf
), "%.200s/.hushlogin", pw
->pw_dir
);
940 #ifdef HAVE_LOGIN_CAP
941 if (login_getcapbool(lc
, "hushlogin", 0) || stat(buf
, &st
) >= 0)
944 if (stat(buf
, &st
) >= 0)
951 * Sets the value of the given variable in the environment. If the variable
952 * already exists, its value is overridden.
955 child_set_env(char ***envp
, u_int
*envsizep
, const char *name
,
963 * If we're passed an uninitialized list, allocate a single null
964 * entry before continuing.
966 if (*envp
== NULL
&& *envsizep
== 0) {
967 *envp
= xmalloc(sizeof(char *));
973 * Find the slot where the value should be stored. If the variable
974 * already exists, we reuse the slot; otherwise we append a new slot
975 * at the end of the array, expanding if necessary.
978 namelen
= strlen(name
);
979 for (i
= 0; env
[i
]; i
++)
980 if (strncmp(env
[i
], name
, namelen
) == 0 && env
[i
][namelen
] == '=')
983 /* Reuse the slot. */
986 /* New variable. Expand if necessary. */
988 if (i
>= envsize
- 1) {
990 fatal("child_set_env: too many env vars");
992 env
= (*envp
) = xrealloc(env
, envsize
, sizeof(char *));
995 /* Need to set the NULL pointer at end of array beyond the new slot. */
999 /* Allocate space and format the variable in the appropriate slot. */
1000 env
[i
] = xmalloc(strlen(name
) + 1 + strlen(value
) + 1);
1001 snprintf(env
[i
], strlen(name
) + 1 + strlen(value
) + 1, "%s=%s", name
, value
);
1005 * Reads environment variables from the given file and adds/overrides them
1006 * into the environment. If the file does not exist, this does nothing.
1007 * Otherwise, it must consist of empty lines, comments (line starts with '#')
1008 * and assignments of the form name=value. No other forms are allowed.
1011 read_environment_file(char ***env
, u_int
*envsize
,
1012 const char *filename
)
1019 f
= fopen(filename
, "r");
1023 while (fgets(buf
, sizeof(buf
), f
)) {
1024 if (++lineno
> 1000)
1025 fatal("Too many lines in environment file %s", filename
);
1026 for (cp
= buf
; *cp
== ' ' || *cp
== '\t'; cp
++)
1028 if (!*cp
|| *cp
== '#' || *cp
== '\n')
1031 cp
[strcspn(cp
, "\n")] = '\0';
1033 value
= strchr(cp
, '=');
1034 if (value
== NULL
) {
1035 fprintf(stderr
, "Bad line %u in %.100s\n", lineno
,
1040 * Replace the equals sign by nul, and advance value to
1045 child_set_env(env
, envsize
, cp
, value
);
1050 #ifdef HAVE_ETC_DEFAULT_LOGIN
1052 * Return named variable from specified environment, or NULL if not present.
1055 child_get_env(char **env
, const char *name
)
1061 for (i
=0; env
[i
] != NULL
; i
++)
1062 if (strncmp(name
, env
[i
], len
) == 0 && env
[i
][len
] == '=')
1063 return(env
[i
] + len
+ 1);
1068 * Read /etc/default/login.
1069 * We pick up the PATH (or SUPATH for root) and UMASK.
1072 read_etc_default_login(char ***env
, u_int
*envsize
, uid_t uid
)
1074 char **tmpenv
= NULL
, *var
;
1075 u_int i
, tmpenvsize
= 0;
1079 * We don't want to copy the whole file to the child's environment,
1080 * so we use a temporary environment and copy the variables we're
1083 read_environment_file(&tmpenv
, &tmpenvsize
, "/etc/default/login");
1089 var
= child_get_env(tmpenv
, "SUPATH");
1091 var
= child_get_env(tmpenv
, "PATH");
1093 child_set_env(env
, envsize
, "PATH", var
);
1095 if ((var
= child_get_env(tmpenv
, "UMASK")) != NULL
)
1096 if (sscanf(var
, "%5lo", &mask
) == 1)
1097 umask((mode_t
)mask
);
1099 for (i
= 0; tmpenv
[i
] != NULL
; i
++)
1103 #endif /* HAVE_ETC_DEFAULT_LOGIN */
1106 copy_environment(char **source
, char ***env
, u_int
*envsize
)
1108 char *var_name
, *var_val
;
1114 for(i
= 0; source
[i
] != NULL
; i
++) {
1115 var_name
= xstrdup(source
[i
]);
1116 if ((var_val
= strstr(var_name
, "=")) == NULL
) {
1122 debug3("Copy environment: %s=%s", var_name
, var_val
);
1123 child_set_env(env
, envsize
, var_name
, var_val
);
1130 do_setup_env(Session
*s
, const char *shell
)
1135 struct passwd
*pw
= s
->pw
;
1136 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN)
1139 extern char **environ
;
1143 /* Initialize the environment. */
1145 env
= xcalloc(envsize
, sizeof(char *));
1150 * The Windows environment contains some setting which are
1151 * important for a running system. They must not be dropped.
1156 p
= fetch_windows_environment();
1157 copy_environment(p
, &env
, &envsize
);
1158 free_windows_environment(p
);
1163 child_set_env(&env
, &envsize
, "TZ", getenv("TZ"));
1166 /* Allow any GSSAPI methods that we've used to alter
1167 * the childs environment as they see fit
1169 ssh_gssapi_do_child(&env
, &envsize
);
1172 if (!options
.use_login
) {
1173 /* Set basic environment. */
1174 for (i
= 0; i
< s
->num_env
; i
++)
1175 child_set_env(&env
, &envsize
, s
->env
[i
].name
,
1178 child_set_env(&env
, &envsize
, "USER", pw
->pw_name
);
1179 child_set_env(&env
, &envsize
, "LOGNAME", pw
->pw_name
);
1181 child_set_env(&env
, &envsize
, "LOGIN", pw
->pw_name
);
1183 child_set_env(&env
, &envsize
, "HOME", pw
->pw_dir
);
1184 snprintf(buf
, sizeof buf
, "%.200s/%.50s",
1185 _PATH_MAILDIR
, pw
->pw_name
);
1186 child_set_env(&env
, &envsize
, "MAIL", buf
);
1187 #ifdef HAVE_LOGIN_CAP
1188 child_set_env(&env
, &envsize
, "PATH", _PATH_STDPATH
);
1189 child_set_env(&env
, &envsize
, "TERM", "su");
1191 environ
= xmalloc(sizeof(char *));
1193 (void) setusercontext(lc
, pw
, pw
->pw_uid
,
1194 LOGIN_SETENV
|LOGIN_SETPATH
);
1195 copy_environment(environ
, &env
, &envsize
);
1198 * This interferes with libc's management of the environment
1199 * in horrible ways that can cause sshd to crash.
1201 for (var
= environ
; *var
!= NULL
; ++var
)
1206 #else /* HAVE_LOGIN_CAP */
1207 # ifndef HAVE_CYGWIN
1209 * There's no standard path on Windows. The path contains
1210 * important components pointing to the system directories,
1211 * needed for loading shared libraries. So the path better
1212 * remains intact here.
1214 # ifdef HAVE_ETC_DEFAULT_LOGIN
1215 read_etc_default_login(&env
, &envsize
, pw
->pw_uid
);
1216 path
= child_get_env(env
, "PATH");
1217 # endif /* HAVE_ETC_DEFAULT_LOGIN */
1218 if (path
== NULL
|| *path
== '\0') {
1219 child_set_env(&env
, &envsize
, "PATH",
1220 s
->pw
->pw_uid
== 0 ?
1221 SUPERUSER_PATH
: _PATH_STDPATH
);
1223 # endif /* HAVE_CYGWIN */
1224 #endif /* HAVE_LOGIN_CAP */
1226 /* Normal systems set SHELL by default. */
1227 child_set_env(&env
, &envsize
, "SHELL", shell
);
1230 /* Set custom environment options from RSA authentication. */
1231 if (!options
.use_login
) {
1232 while (custom_environment
) {
1233 struct envstring
*ce
= custom_environment
;
1236 for (i
= 0; str
[i
] != '=' && str
[i
]; i
++)
1238 if (str
[i
] == '=') {
1240 child_set_env(&env
, &envsize
, str
, str
+ i
+ 1);
1242 custom_environment
= ce
->next
;
1248 /* SSH_CLIENT deprecated */
1249 snprintf(buf
, sizeof buf
, "%.50s %d %d",
1250 get_remote_ipaddr(), get_remote_port(), get_local_port());
1251 child_set_env(&env
, &envsize
, "SSH_CLIENT", buf
);
1253 laddr
= get_local_ipaddr(packet_get_connection_in());
1254 snprintf(buf
, sizeof buf
, "%.50s %d %.50s %d",
1255 get_remote_ipaddr(), get_remote_port(), laddr
, get_local_port());
1257 child_set_env(&env
, &envsize
, "SSH_CONNECTION", buf
);
1260 child_set_env(&env
, &envsize
, "SSH_TTY", s
->tty
);
1262 child_set_env(&env
, &envsize
, "TERM", s
->term
);
1264 child_set_env(&env
, &envsize
, "DISPLAY", s
->display
);
1265 if (original_command
)
1266 child_set_env(&env
, &envsize
, "SSH_ORIGINAL_COMMAND",
1270 if (cray_tmpdir
[0] != '\0')
1271 child_set_env(&env
, &envsize
, "TMPDIR", cray_tmpdir
);
1272 #endif /* _UNICOS */
1275 * Since we clear KRB5CCNAME at startup, if it's set now then it
1276 * must have been set by a native authentication method (eg AIX or
1277 * SIA), so copy it to the child.
1282 if ((cp
= getenv("KRB5CCNAME")) != NULL
)
1283 child_set_env(&env
, &envsize
, "KRB5CCNAME", cp
);
1290 if ((cp
= getenv("AUTHSTATE")) != NULL
)
1291 child_set_env(&env
, &envsize
, "AUTHSTATE", cp
);
1292 read_environment_file(&env
, &envsize
, "/etc/environment");
1296 if (s
->authctxt
->krb5_ccname
)
1297 child_set_env(&env
, &envsize
, "KRB5CCNAME",
1298 s
->authctxt
->krb5_ccname
);
1302 * Pull in any environment variables that may have
1305 if (options
.use_pam
) {
1308 p
= fetch_pam_child_environment();
1309 copy_environment(p
, &env
, &envsize
);
1310 free_pam_environment(p
);
1312 p
= fetch_pam_environment();
1313 copy_environment(p
, &env
, &envsize
);
1314 free_pam_environment(p
);
1316 #endif /* USE_PAM */
1318 if (auth_sock_name
!= NULL
)
1319 child_set_env(&env
, &envsize
, SSH_AUTHSOCKET_ENV_NAME
,
1322 /* read $HOME/.ssh/environment. */
1323 if (options
.permit_user_env
&& !options
.use_login
) {
1324 snprintf(buf
, sizeof buf
, "%.200s/.ssh/environment",
1325 strcmp(pw
->pw_dir
, "/") ? pw
->pw_dir
: "");
1326 read_environment_file(&env
, &envsize
, buf
);
1329 /* dump the environment */
1330 fprintf(stderr
, "Environment:\n");
1331 for (i
= 0; env
[i
]; i
++)
1332 fprintf(stderr
, " %.200s\n", env
[i
]);
1338 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found
1339 * first in this order).
1342 do_rc_files(Session
*s
, const char *shell
)
1350 s
->display
!= NULL
&& s
->auth_proto
!= NULL
&& s
->auth_data
!= NULL
;
1352 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */
1353 if (!s
->is_subsystem
&& options
.adm_forced_command
== NULL
&&
1354 !no_user_rc
&& stat(_PATH_SSH_USER_RC
, &st
) >= 0) {
1355 snprintf(cmd
, sizeof cmd
, "%s -c '%s %s'",
1356 shell
, _PATH_BSHELL
, _PATH_SSH_USER_RC
);
1358 fprintf(stderr
, "Running %s\n", cmd
);
1359 f
= popen(cmd
, "w");
1362 fprintf(f
, "%s %s\n", s
->auth_proto
,
1366 fprintf(stderr
, "Could not run %s\n",
1368 } else if (stat(_PATH_SSH_SYSTEM_RC
, &st
) >= 0) {
1370 fprintf(stderr
, "Running %s %s\n", _PATH_BSHELL
,
1371 _PATH_SSH_SYSTEM_RC
);
1372 f
= popen(_PATH_BSHELL
" " _PATH_SSH_SYSTEM_RC
, "w");
1375 fprintf(f
, "%s %s\n", s
->auth_proto
,
1379 fprintf(stderr
, "Could not run %s\n",
1380 _PATH_SSH_SYSTEM_RC
);
1381 } else if (do_xauth
&& options
.xauth_location
!= NULL
) {
1382 /* Add authority data to .Xauthority if appropriate. */
1385 "Running %.500s remove %.100s\n",
1386 options
.xauth_location
, s
->auth_display
);
1388 "%.500s add %.100s %.100s %.100s\n",
1389 options
.xauth_location
, s
->auth_display
,
1390 s
->auth_proto
, s
->auth_data
);
1392 snprintf(cmd
, sizeof cmd
, "%s -q -",
1393 options
.xauth_location
);
1394 f
= popen(cmd
, "w");
1396 fprintf(f
, "remove %s\n",
1398 fprintf(f
, "add %s %s %s\n",
1399 s
->auth_display
, s
->auth_proto
,
1403 fprintf(stderr
, "Could not run %s\n",
1410 do_nologin(struct passwd
*pw
)
1415 #ifdef HAVE_LOGIN_CAP
1416 if (!login_getcapbool(lc
, "ignorenologin", 0) && pw
->pw_uid
)
1417 f
= fopen(login_getcapstr(lc
, "nologin", _PATH_NOLOGIN
,
1418 _PATH_NOLOGIN
), "r");
1421 f
= fopen(_PATH_NOLOGIN
, "r");
1424 /* /etc/nologin exists. Print its contents and exit. */
1425 logit("User %.100s not allowed because %s exists",
1426 pw
->pw_name
, _PATH_NOLOGIN
);
1427 while (fgets(buf
, sizeof(buf
), f
))
1436 * Chroot into a directory after checking it for safety: all path components
1437 * must be root-owned directories with strict permissions.
1440 safely_chroot(const char *path
, uid_t uid
)
1443 char component
[MAXPATHLEN
];
1447 fatal("chroot path does not begin at root");
1448 if (strlen(path
) >= sizeof(component
))
1449 fatal("chroot path too long");
1452 * Descend the path, checking that each component is a
1453 * root-owned directory with strict permissions.
1455 for (cp
= path
; cp
!= NULL
;) {
1456 if ((cp
= strchr(cp
, '/')) == NULL
)
1457 strlcpy(component
, path
, sizeof(component
));
1460 memcpy(component
, path
, cp
- path
);
1461 component
[cp
- path
] = '\0';
1464 debug3("%s: checking '%s'", __func__
, component
);
1466 if (stat(component
, &st
) != 0)
1467 fatal("%s: stat(\"%s\"): %s", __func__
,
1468 component
, strerror(errno
));
1469 if (st
.st_uid
!= 0 || (st
.st_mode
& 022) != 0)
1470 fatal("bad ownership or modes for chroot "
1471 "directory %s\"%s\"",
1472 cp
== NULL
? "" : "component ", component
);
1473 if (!S_ISDIR(st
.st_mode
))
1474 fatal("chroot path %s\"%s\" is not a directory",
1475 cp
== NULL
? "" : "component ", component
);
1479 if (chdir(path
) == -1)
1480 fatal("Unable to chdir to chroot path \"%s\": "
1481 "%s", path
, strerror(errno
));
1482 if (chroot(path
) == -1)
1483 fatal("chroot(\"%s\"): %s", path
, strerror(errno
));
1484 if (chdir("/") == -1)
1485 fatal("%s: chdir(/) after chroot: %s",
1486 __func__
, strerror(errno
));
1487 verbose("Changed root directory to \"%s\"", path
);
1490 /* Set login name, uid, gid, and groups. */
1492 do_setusercontext(struct passwd
*pw
)
1494 char *chroot_path
, *tmp
;
1497 /* Cache selinux status for later use */
1498 (void)ssh_selinux_enabled();
1502 if (getuid() == 0 || geteuid() == 0)
1503 #endif /* HAVE_CYGWIN */
1505 #ifdef HAVE_LOGIN_CAP
1510 if (options
.use_pam
) {
1511 do_pam_setcred(use_privsep
);
1513 # endif /* USE_PAM */
1514 if (setusercontext(lc
, pw
, pw
->pw_uid
,
1515 (LOGIN_SETALL
& ~(LOGIN_SETPATH
|LOGIN_SETUSER
))) < 0) {
1516 perror("unable to set user context");
1520 # if defined(HAVE_GETLUID) && defined(HAVE_SETLUID)
1521 /* Sets login uid for accounting */
1522 if (getluid() == -1 && setluid(pw
->pw_uid
) == -1)
1523 error("setluid: %s", strerror(errno
));
1524 # endif /* defined(HAVE_GETLUID) && defined(HAVE_SETLUID) */
1526 if (setlogin(pw
->pw_name
) < 0)
1527 error("setlogin failed: %s", strerror(errno
));
1528 if (setgid(pw
->pw_gid
) < 0) {
1532 /* Initialize the group list. */
1533 if (initgroups(pw
->pw_name
, pw
->pw_gid
) < 0) {
1534 perror("initgroups");
1540 * PAM credentials may take the form of supplementary groups.
1541 * These will have been wiped by the above initgroups() call.
1542 * Reestablish them here.
1544 if (options
.use_pam
) {
1545 do_pam_setcred(use_privsep
);
1547 # endif /* USE_PAM */
1548 # if defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY)
1549 irix_setusercontext(pw
);
1550 # endif /* defined(WITH_IRIX_PROJECT) || defined(WITH_IRIX_JOBS) || defined(WITH_IRIX_ARRAY) */
1555 if (set_id(pw
->pw_name
) != 0) {
1558 # endif /* USE_LIBIAF */
1561 if (options
.chroot_directory
!= NULL
&&
1562 strcasecmp(options
.chroot_directory
, "none") != 0) {
1563 tmp
= tilde_expand_filename(options
.chroot_directory
,
1565 chroot_path
= percent_expand(tmp
, "h", pw
->pw_dir
,
1566 "u", pw
->pw_name
, (char *)NULL
);
1567 safely_chroot(chroot_path
, pw
->pw_uid
);
1572 #ifdef HAVE_SETPCRED
1573 if (setpcred(pw
->pw_name
, (char **)NULL
) == -1)
1574 fatal("Failed to set process credentials");
1575 #endif /* HAVE_SETPCRED */
1576 #ifdef HAVE_LOGIN_CAP
1577 if (setusercontext(lc
, pw
, pw
->pw_uid
, LOGIN_SETUSER
) < 0) {
1578 perror("unable to set user context (setuser)");
1582 /* Permanently switch to the desired uid. */
1583 permanently_set_uid(pw
);
1587 if (getuid() != pw
->pw_uid
|| geteuid() != pw
->pw_uid
)
1588 fatal("Failed to set uids to %u.", (u_int
) pw
->pw_uid
);
1591 ssh_selinux_setup_exec_context(pw
->pw_name
);
1596 do_pwchange(Session
*s
)
1599 fprintf(stderr
, "WARNING: Your password has expired.\n");
1600 if (s
->ttyfd
!= -1) {
1602 "You must change your password now and login again!\n");
1603 #ifdef PASSWD_NEEDS_USERNAME
1604 execl(_PATH_PASSWD_PROG
, "passwd", s
->pw
->pw_name
,
1607 execl(_PATH_PASSWD_PROG
, "passwd", (char *)NULL
);
1612 "Password change required but no TTY available.\n");
1618 launch_login(struct passwd
*pw
, const char *hostname
)
1620 /* Launch login(1). */
1622 execl(LOGIN_PROGRAM
, "login", "-h", hostname
,
1623 #ifdef xxxLOGIN_NEEDS_TERM
1624 (s
->term
? s
->term
: "unknown"),
1625 #endif /* LOGIN_NEEDS_TERM */
1626 #ifdef LOGIN_NO_ENDOPT
1627 "-p", "-f", pw
->pw_name
, (char *)NULL
);
1629 "-p", "-f", "--", pw
->pw_name
, (char *)NULL
);
1632 /* Login couldn't be executed, die. */
1639 child_close_fds(void)
1643 if (packet_get_connection_in() == packet_get_connection_out())
1644 close(packet_get_connection_in());
1646 close(packet_get_connection_in());
1647 close(packet_get_connection_out());
1650 * Close all descriptors related to channels. They will still remain
1651 * open in the parent.
1653 /* XXX better use close-on-exec? -markus */
1654 channel_close_all();
1657 * Close any extra file descriptors. Note that there may still be
1658 * descriptors left by system functions. They will be closed later.
1663 * Close any extra open file descriptors so that we don't have them
1664 * hanging around in clients. Note that we want to do this after
1665 * initgroups, because at least on Solaris 2.3 it leaves file
1668 for (i
= 3; i
< 64; i
++)
1673 * Performs common processing for the child, such as setting up the
1674 * environment, closing extra file descriptors, setting the user and group
1675 * ids, and executing the command or shell.
1679 do_child(Session
*s
, const char *command
)
1681 extern char **environ
;
1683 char *argv
[ARGV_MAX
];
1684 const char *shell
, *shell0
, *hostname
= NULL
;
1685 struct passwd
*pw
= s
->pw
;
1688 /* remove hostkey from the child's memory */
1689 destroy_sensitive_data();
1691 /* Force a password change */
1692 if (s
->authctxt
->force_pwchange
) {
1693 do_setusercontext(pw
);
1699 /* login(1) is only called if we execute the login shell */
1700 if (options
.use_login
&& command
!= NULL
)
1701 options
.use_login
= 0;
1704 cray_setup(pw
->pw_uid
, pw
->pw_name
, command
);
1705 #endif /* _UNICOS */
1708 * Login(1) does this as well, and it needs uid 0 for the "-h"
1709 * switch, so we let login(1) to this for us.
1711 if (!options
.use_login
) {
1713 session_setup_sia(pw
, s
->ttyfd
== -1 ? NULL
: s
->tty
);
1714 if (!check_quietlogin(s
, command
))
1716 #else /* HAVE_OSF_SIA */
1717 /* When PAM is enabled we rely on it to do the nologin check */
1718 if (!options
.use_pam
)
1720 do_setusercontext(pw
);
1722 * PAM session modules in do_setusercontext may have
1723 * generated messages, so if this in an interactive
1724 * login then display them too.
1726 if (!check_quietlogin(s
, command
))
1728 #endif /* HAVE_OSF_SIA */
1732 if (options
.use_pam
&& !options
.use_login
&& !is_pam_session_open()) {
1733 debug3("PAM session not opened, exiting");
1740 * Get the shell from the password data. An empty shell field is
1741 * legal, and means /bin/sh.
1743 shell
= (pw
->pw_shell
[0] == '\0') ? _PATH_BSHELL
: pw
->pw_shell
;
1746 * Make sure $SHELL points to the shell from the password file,
1747 * even if shell is overridden from login.conf
1749 env
= do_setup_env(s
, shell
);
1751 #ifdef HAVE_LOGIN_CAP
1752 shell
= login_getcapstr(lc
, "shell", (char *)shell
, (char *)shell
);
1755 /* we have to stash the hostname before we close our socket. */
1756 if (options
.use_login
)
1757 hostname
= get_remote_name_or_ip(utmp_len
,
1760 * Close the connection descriptors; note that this is the child, and
1761 * the server will still have the socket open, and it is important
1762 * that we do not shutdown it. Note that the descriptors cannot be
1763 * closed before building the environment, as we call
1764 * get_remote_ipaddr there.
1769 * Must take new environment into use so that .ssh/rc,
1770 * /etc/ssh/sshrc and xauth are run in the proper environment.
1774 #if defined(KRB5) && defined(USE_AFS)
1776 * At this point, we check to see if AFS is active and if we have
1777 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see
1778 * if we can (and need to) extend the ticket into an AFS token. If
1779 * we don't do this, we run into potential problems if the user's
1780 * home directory is in AFS and it's not world-readable.
1783 if (options
.kerberos_get_afs_token
&& k_hasafs() &&
1784 (s
->authctxt
->krb5_ctx
!= NULL
)) {
1787 debug("Getting AFS token");
1791 if (k_afs_cell_of_file(pw
->pw_dir
, cell
, sizeof(cell
)) == 0)
1792 krb5_afslog(s
->authctxt
->krb5_ctx
,
1793 s
->authctxt
->krb5_fwd_ccache
, cell
, NULL
);
1795 krb5_afslog_home(s
->authctxt
->krb5_ctx
,
1796 s
->authctxt
->krb5_fwd_ccache
, NULL
, NULL
, pw
->pw_dir
);
1800 /* Change current directory to the user's home directory. */
1801 if (chdir(pw
->pw_dir
) < 0) {
1802 /* Suppress missing homedir warning for chroot case */
1803 #ifdef HAVE_LOGIN_CAP
1804 r
= login_getcapbool(lc
, "requirehome", 0);
1806 if (r
|| options
.chroot_directory
== NULL
)
1807 fprintf(stderr
, "Could not chdir to home "
1808 "directory %s: %s\n", pw
->pw_dir
,
1814 closefrom(STDERR_FILENO
+ 1);
1816 if (!options
.use_login
)
1817 do_rc_files(s
, shell
);
1819 /* restore SIGPIPE for child */
1820 signal(SIGPIPE
, SIG_DFL
);
1822 if (s
->is_subsystem
== SUBSYSTEM_INT_SFTP
) {
1823 extern int optind
, optreset
;
1827 setproctitle("%s@%s", s
->pw
->pw_name
, INTERNAL_SFTP_NAME
);
1828 args
= xstrdup(command
? command
: "sftp-server");
1829 for (i
= 0, (p
= strtok(args
, " ")); p
; (p
= strtok(NULL
, " ")))
1830 if (i
< ARGV_MAX
- 1)
1833 optind
= optreset
= 1;
1834 __progname
= argv
[0];
1835 exit(sftp_server_main(i
, argv
, s
->pw
));
1838 if (options
.use_login
) {
1839 launch_login(pw
, hostname
);
1843 /* Get the last component of the shell name. */
1844 if ((shell0
= strrchr(shell
, '/')) != NULL
)
1850 * If we have no command, execute the shell. In this case, the shell
1851 * name to be passed in argv[0] is preceded by '-' to indicate that
1852 * this is a login shell.
1857 /* Start the shell. Set initial character to '-'. */
1860 if (strlcpy(argv0
+ 1, shell0
, sizeof(argv0
) - 1)
1861 >= sizeof(argv0
) - 1) {
1867 /* Execute the shell. */
1870 execve(shell
, argv
, env
);
1872 /* Executing the shell failed. */
1877 * Execute the command using the user's shell. This uses the -c
1878 * option to execute the command.
1880 argv
[0] = (char *) shell0
;
1882 argv
[2] = (char *) command
;
1884 execve(shell
, argv
, env
);
1890 session_unused(int id
)
1892 debug3("%s: session id %d unused", __func__
, id
);
1893 if (id
>= options
.max_sessions
||
1894 id
>= sessions_nalloc
) {
1895 fatal("%s: insane session id %d (max %d nalloc %d)",
1896 __func__
, id
, options
.max_sessions
, sessions_nalloc
);
1898 bzero(&sessions
[id
], sizeof(*sessions
));
1899 sessions
[id
].self
= id
;
1900 sessions
[id
].used
= 0;
1901 sessions
[id
].chanid
= -1;
1902 sessions
[id
].ptyfd
= -1;
1903 sessions
[id
].ttyfd
= -1;
1904 sessions
[id
].ptymaster
= -1;
1905 sessions
[id
].x11_chanids
= NULL
;
1906 sessions
[id
].next_unused
= sessions_first_unused
;
1907 sessions_first_unused
= id
;
1915 if (sessions_first_unused
== -1) {
1916 if (sessions_nalloc
>= options
.max_sessions
)
1918 debug2("%s: allocate (allocated %d max %d)",
1919 __func__
, sessions_nalloc
, options
.max_sessions
);
1920 tmp
= xrealloc(sessions
, sessions_nalloc
+ 1,
1923 error("%s: cannot allocate %d sessions",
1924 __func__
, sessions_nalloc
+ 1);
1928 session_unused(sessions_nalloc
++);
1931 if (sessions_first_unused
>= sessions_nalloc
||
1932 sessions_first_unused
< 0) {
1933 fatal("%s: insane first_unused %d max %d nalloc %d",
1934 __func__
, sessions_first_unused
, options
.max_sessions
,
1938 s
= &sessions
[sessions_first_unused
];
1940 fatal("%s: session %d already used",
1941 __func__
, sessions_first_unused
);
1943 sessions_first_unused
= s
->next_unused
;
1945 s
->next_unused
= -1;
1946 debug("session_new: session %d", s
->self
);
1955 for (i
= 0; i
< sessions_nalloc
; i
++) {
1956 Session
*s
= &sessions
[i
];
1958 debug("dump: used %d next_unused %d session %d %p "
1959 "channel %d pid %ld",
1970 session_open(Authctxt
*authctxt
, int chanid
)
1972 Session
*s
= session_new();
1973 debug("session_open: channel %d", chanid
);
1975 error("no more sessions");
1978 s
->authctxt
= authctxt
;
1979 s
->pw
= authctxt
->pw
;
1980 if (s
->pw
== NULL
|| !authctxt
->valid
)
1981 fatal("no user for session %d", s
->self
);
1982 debug("session_open: session %d: link with channel %d", s
->self
, chanid
);
1988 session_by_tty(char *tty
)
1991 for (i
= 0; i
< sessions_nalloc
; i
++) {
1992 Session
*s
= &sessions
[i
];
1993 if (s
->used
&& s
->ttyfd
!= -1 && strcmp(s
->tty
, tty
) == 0) {
1994 debug("session_by_tty: session %d tty %s", i
, tty
);
1998 debug("session_by_tty: unknown tty %.100s", tty
);
2004 session_by_channel(int id
)
2007 for (i
= 0; i
< sessions_nalloc
; i
++) {
2008 Session
*s
= &sessions
[i
];
2009 if (s
->used
&& s
->chanid
== id
) {
2010 debug("session_by_channel: session %d channel %d",
2015 debug("session_by_channel: unknown channel %d", id
);
2021 session_by_x11_channel(int id
)
2025 for (i
= 0; i
< sessions_nalloc
; i
++) {
2026 Session
*s
= &sessions
[i
];
2028 if (s
->x11_chanids
== NULL
|| !s
->used
)
2030 for (j
= 0; s
->x11_chanids
[j
] != -1; j
++) {
2031 if (s
->x11_chanids
[j
] == id
) {
2032 debug("session_by_x11_channel: session %d "
2033 "channel %d", s
->self
, id
);
2038 debug("session_by_x11_channel: unknown channel %d", id
);
2044 session_by_pid(pid_t pid
)
2047 debug("session_by_pid: pid %ld", (long)pid
);
2048 for (i
= 0; i
< sessions_nalloc
; i
++) {
2049 Session
*s
= &sessions
[i
];
2050 if (s
->used
&& s
->pid
== pid
)
2053 error("session_by_pid: unknown pid %ld", (long)pid
);
2059 session_window_change_req(Session
*s
)
2061 s
->col
= packet_get_int();
2062 s
->row
= packet_get_int();
2063 s
->xpixel
= packet_get_int();
2064 s
->ypixel
= packet_get_int();
2066 pty_change_window_size(s
->ptyfd
, s
->row
, s
->col
, s
->xpixel
, s
->ypixel
);
2071 session_pty_req(Session
*s
)
2077 debug("Allocating a pty not permitted for this authentication.");
2080 if (s
->ttyfd
!= -1) {
2081 packet_disconnect("Protocol error: you already have a pty.");
2085 s
->term
= packet_get_string(&len
);
2088 s
->col
= packet_get_int();
2089 s
->row
= packet_get_int();
2091 s
->row
= packet_get_int();
2092 s
->col
= packet_get_int();
2094 s
->xpixel
= packet_get_int();
2095 s
->ypixel
= packet_get_int();
2097 if (strcmp(s
->term
, "") == 0) {
2102 /* Allocate a pty and open it. */
2103 debug("Allocating pty.");
2104 if (!PRIVSEP(pty_allocate(&s
->ptyfd
, &s
->ttyfd
, s
->tty
,
2111 error("session_pty_req: session %d alloc failed", s
->self
);
2114 debug("session_pty_req: session %d alloc %s", s
->self
, s
->tty
);
2116 /* for SSH1 the tty modes length is not given */
2118 n_bytes
= packet_remaining();
2119 tty_parse_modes(s
->ttyfd
, &n_bytes
);
2122 pty_setowner(s
->pw
, s
->tty
);
2124 /* Set window size from the packet. */
2125 pty_change_window_size(s
->ptyfd
, s
->row
, s
->col
, s
->xpixel
, s
->ypixel
);
2128 session_proctitle(s
);
2133 session_subsystem_req(Session
*s
)
2138 char *prog
, *cmd
, *subsys
= packet_get_string(&len
);
2142 logit("subsystem request for %.100s", subsys
);
2144 for (i
= 0; i
< options
.num_subsystems
; i
++) {
2145 if (strcmp(subsys
, options
.subsystem_name
[i
]) == 0) {
2146 prog
= options
.subsystem_command
[i
];
2147 cmd
= options
.subsystem_args
[i
];
2148 if (!strcmp(INTERNAL_SFTP_NAME
, prog
)) {
2149 s
->is_subsystem
= SUBSYSTEM_INT_SFTP
;
2150 } else if (stat(prog
, &st
) < 0) {
2151 error("subsystem: cannot stat %s: %s", prog
,
2155 s
->is_subsystem
= SUBSYSTEM_EXT
;
2157 debug("subsystem: exec() %s", cmd
);
2158 success
= do_exec(s
, cmd
) == 0;
2164 logit("subsystem request for %.100s failed, subsystem not found",
2172 session_x11_req(Session
*s
)
2176 if (s
->auth_proto
!= NULL
|| s
->auth_data
!= NULL
) {
2177 error("session_x11_req: session %d: "
2178 "x11 forwarding already active", s
->self
);
2181 s
->single_connection
= packet_get_char();
2182 s
->auth_proto
= packet_get_string(NULL
);
2183 s
->auth_data
= packet_get_string(NULL
);
2184 s
->screen
= packet_get_int();
2187 success
= session_setup_x11fwd(s
);
2189 xfree(s
->auth_proto
);
2190 xfree(s
->auth_data
);
2191 s
->auth_proto
= NULL
;
2192 s
->auth_data
= NULL
;
2198 session_shell_req(Session
*s
)
2201 return do_exec(s
, NULL
) == 0;
2205 session_exec_req(Session
*s
)
2209 char *command
= packet_get_string(&len
);
2211 success
= do_exec(s
, command
) == 0;
2217 session_break_req(Session
*s
)
2220 packet_get_int(); /* ignored */
2223 if (s
->ttyfd
== -1 || tcsendbreak(s
->ttyfd
, 0) < 0)
2229 session_env_req(Session
*s
)
2232 u_int name_len
, val_len
, i
;
2234 name
= packet_get_string(&name_len
);
2235 val
= packet_get_string(&val_len
);
2238 /* Don't set too many environment variables */
2239 if (s
->num_env
> 128) {
2240 debug2("Ignoring env request %s: too many env vars", name
);
2244 for (i
= 0; i
< options
.num_accept_env
; i
++) {
2245 if (match_pattern(name
, options
.accept_env
[i
])) {
2246 debug2("Setting env %d: %s=%s", s
->num_env
, name
, val
);
2247 s
->env
= xrealloc(s
->env
, s
->num_env
+ 1,
2249 s
->env
[s
->num_env
].name
= name
;
2250 s
->env
[s
->num_env
].val
= val
;
2255 debug2("Ignoring env request %s: disallowed name", name
);
2264 session_auth_agent_req(Session
*s
)
2266 static int called
= 0;
2268 if (no_agent_forwarding_flag
|| !options
.allow_agent_forwarding
) {
2269 debug("session_auth_agent_req: no_agent_forwarding_flag");
2276 return auth_input_request_forwarding(s
->pw
);
2281 session_input_channel_req(Channel
*c
, const char *rtype
)
2286 if ((s
= session_by_channel(c
->self
)) == NULL
) {
2287 logit("session_input_channel_req: no session %d req %.100s",
2291 debug("session_input_channel_req: session %d req %s", s
->self
, rtype
);
2294 * a session is in LARVAL state until a shell, a command
2295 * or a subsystem is executed
2297 if (c
->type
== SSH_CHANNEL_LARVAL
) {
2298 if (strcmp(rtype
, "shell") == 0) {
2299 success
= session_shell_req(s
);
2300 } else if (strcmp(rtype
, "exec") == 0) {
2301 success
= session_exec_req(s
);
2302 } else if (strcmp(rtype
, "pty-req") == 0) {
2303 success
= session_pty_req(s
);
2304 } else if (strcmp(rtype
, "x11-req") == 0) {
2305 success
= session_x11_req(s
);
2306 } else if (strcmp(rtype
, "auth-agent-req@openssh.com") == 0) {
2307 success
= session_auth_agent_req(s
);
2308 } else if (strcmp(rtype
, "subsystem") == 0) {
2309 success
= session_subsystem_req(s
);
2310 } else if (strcmp(rtype
, "env") == 0) {
2311 success
= session_env_req(s
);
2314 if (strcmp(rtype
, "window-change") == 0) {
2315 success
= session_window_change_req(s
);
2316 } else if (strcmp(rtype
, "break") == 0) {
2317 success
= session_break_req(s
);
2324 session_set_fds(Session
*s
, int fdin
, int fdout
, int fderr
, int is_tty
)
2327 fatal("session_set_fds: called for proto != 2.0");
2329 * now that have a child and a pipe to the child,
2330 * we can activate our channel and register the fd's
2332 if (s
->chanid
== -1)
2333 fatal("no channel for session %d", s
->self
);
2334 if (options
.hpn_disabled
)
2335 channel_set_fds(s
->chanid
,
2337 fderr
== -1 ? CHAN_EXTENDED_IGNORE
: CHAN_EXTENDED_READ
,
2338 1, is_tty
, CHAN_SES_WINDOW_DEFAULT
);
2340 channel_set_fds(s
->chanid
,
2342 fderr
== -1 ? CHAN_EXTENDED_IGNORE
: CHAN_EXTENDED_READ
,
2343 1, is_tty
, options
.hpn_buffer_size
);
2347 * Function to perform pty cleanup. Also called if we get aborted abnormally
2348 * (e.g., due to a dropped connection).
2351 session_pty_cleanup2(Session
*s
)
2354 error("session_pty_cleanup: no session");
2360 debug("session_pty_cleanup: session %d release %s", s
->self
, s
->tty
);
2362 /* Record that the user has logged out. */
2364 record_logout(s
->pid
, s
->tty
, s
->pw
->pw_name
);
2366 /* Release the pseudo-tty. */
2368 pty_release(s
->tty
);
2371 * Close the server side of the socket pairs. We must do this after
2372 * the pty cleanup, so that another process doesn't get this pty
2373 * while we're still cleaning up.
2375 if (s
->ptymaster
!= -1 && close(s
->ptymaster
) < 0)
2376 error("close(s->ptymaster/%d): %s",
2377 s
->ptymaster
, strerror(errno
));
2379 /* unlink pty from session */
2384 session_pty_cleanup(Session
*s
)
2386 PRIVSEP(session_pty_cleanup2(s
));
2392 #define SSH_SIG(x) if (sig == SIG ## x) return #x
2407 return "SIG@openssh.com";
2411 session_close_x11(int id
)
2415 if ((c
= channel_by_id(id
)) == NULL
) {
2416 debug("session_close_x11: x11 channel %d missing", id
);
2418 /* Detach X11 listener */
2419 debug("session_close_x11: detach x11 channel %d", id
);
2420 channel_cancel_cleanup(id
);
2421 if (c
->ostate
!= CHAN_OUTPUT_CLOSED
)
2427 session_close_single_x11(int id
, void *arg
)
2432 debug3("session_close_single_x11: channel %d", id
);
2433 channel_cancel_cleanup(id
);
2434 if ((s
= session_by_x11_channel(id
)) == NULL
)
2435 fatal("session_close_single_x11: no x11 channel %d", id
);
2436 for (i
= 0; s
->x11_chanids
[i
] != -1; i
++) {
2437 debug("session_close_single_x11: session %d: "
2438 "closing channel %d", s
->self
, s
->x11_chanids
[i
]);
2440 * The channel "id" is already closing, but make sure we
2441 * close all of its siblings.
2443 if (s
->x11_chanids
[i
] != id
)
2444 session_close_x11(s
->x11_chanids
[i
]);
2446 xfree(s
->x11_chanids
);
2447 s
->x11_chanids
= NULL
;
2452 if (s
->auth_proto
) {
2453 xfree(s
->auth_proto
);
2454 s
->auth_proto
= NULL
;
2457 xfree(s
->auth_data
);
2458 s
->auth_data
= NULL
;
2460 if (s
->auth_display
) {
2461 xfree(s
->auth_display
);
2462 s
->auth_display
= NULL
;
2467 session_exit_message(Session
*s
, int status
)
2471 if ((c
= channel_lookup(s
->chanid
)) == NULL
)
2472 fatal("session_exit_message: session %d: no channel %d",
2473 s
->self
, s
->chanid
);
2474 debug("session_exit_message: session %d channel %d pid %ld",
2475 s
->self
, s
->chanid
, (long)s
->pid
);
2477 if (WIFEXITED(status
)) {
2478 channel_request_start(s
->chanid
, "exit-status", 0);
2479 packet_put_int(WEXITSTATUS(status
));
2481 } else if (WIFSIGNALED(status
)) {
2482 channel_request_start(s
->chanid
, "exit-signal", 0);
2483 packet_put_cstring(sig2name(WTERMSIG(status
)));
2485 packet_put_char(WCOREDUMP(status
)? 1 : 0);
2486 #else /* WCOREDUMP */
2488 #endif /* WCOREDUMP */
2489 packet_put_cstring("");
2490 packet_put_cstring("");
2493 /* Some weird exit cause. Just exit. */
2494 packet_disconnect("wait returned status %04x.", status
);
2497 /* disconnect channel */
2498 debug("session_exit_message: release channel %d", s
->chanid
);
2501 * Adjust cleanup callback attachment to send close messages when
2502 * the channel gets EOF. The session will be then be closed
2503 * by session_close_by_channel when the childs close their fds.
2505 channel_register_cleanup(c
->self
, session_close_by_channel
, 1);
2508 * emulate a write failure with 'chan_write_failed', nobody will be
2509 * interested in data we write.
2510 * Note that we must not call 'chan_read_failed', since there could
2511 * be some more data waiting in the pipe.
2513 if (c
->ostate
!= CHAN_OUTPUT_CLOSED
)
2514 chan_write_failed(c
);
2518 session_close(Session
*s
)
2522 debug("session_close: session %d pid %ld", s
->self
, (long)s
->pid
);
2524 session_pty_cleanup(s
);
2530 xfree(s
->x11_chanids
);
2531 if (s
->auth_display
)
2532 xfree(s
->auth_display
);
2534 xfree(s
->auth_data
);
2536 xfree(s
->auth_proto
);
2537 if (s
->env
!= NULL
) {
2538 for (i
= 0; i
< s
->num_env
; i
++) {
2539 xfree(s
->env
[i
].name
);
2540 xfree(s
->env
[i
].val
);
2544 session_proctitle(s
);
2545 session_unused(s
->self
);
2549 session_close_by_pid(pid_t pid
, int status
)
2551 Session
*s
= session_by_pid(pid
);
2553 debug("session_close_by_pid: no session for pid %ld",
2557 if (s
->chanid
!= -1)
2558 session_exit_message(s
, status
);
2560 session_pty_cleanup(s
);
2565 * this is called when a channel dies before
2566 * the session 'child' itself dies
2569 session_close_by_channel(int id
, void *arg
)
2571 Session
*s
= session_by_channel(id
);
2575 debug("session_close_by_channel: no session for id %d", id
);
2578 debug("session_close_by_channel: channel %d child %ld",
2581 debug("session_close_by_channel: channel %d: has child", id
);
2583 * delay detach of session, but release pty, since
2584 * the fd's to the child are already closed
2587 session_pty_cleanup(s
);
2590 /* detach by removing callback */
2591 channel_cancel_cleanup(s
->chanid
);
2593 /* Close any X11 listeners associated with this session */
2594 if (s
->x11_chanids
!= NULL
) {
2595 for (i
= 0; s
->x11_chanids
[i
] != -1; i
++) {
2596 session_close_x11(s
->x11_chanids
[i
]);
2597 s
->x11_chanids
[i
] = -1;
2606 session_destroy_all(void (*closefunc
)(Session
*))
2609 for (i
= 0; i
< sessions_nalloc
; i
++) {
2610 Session
*s
= &sessions
[i
];
2612 if (closefunc
!= NULL
)
2621 session_tty_list(void)
2623 static char buf
[1024];
2628 for (i
= 0; i
< sessions_nalloc
; i
++) {
2629 Session
*s
= &sessions
[i
];
2630 if (s
->used
&& s
->ttyfd
!= -1) {
2632 if (strncmp(s
->tty
, "/dev/", 5) != 0) {
2633 cp
= strrchr(s
->tty
, '/');
2634 cp
= (cp
== NULL
) ? s
->tty
: cp
+ 1;
2639 strlcat(buf
, ",", sizeof buf
);
2640 strlcat(buf
, cp
, sizeof buf
);
2644 strlcpy(buf
, "notty", sizeof buf
);
2649 session_proctitle(Session
*s
)
2652 error("no user for session %d", s
->self
);
2654 setproctitle("%s@%s", s
->pw
->pw_name
, session_tty_list());
2658 session_setup_x11fwd(Session
*s
)
2661 char display
[512], auth_display
[512];
2662 char hostname
[MAXHOSTNAMELEN
];
2665 if (no_x11_forwarding_flag
) {
2666 packet_send_debug("X11 forwarding disabled in user configuration file.");
2669 if (!options
.x11_forwarding
) {
2670 debug("X11 forwarding disabled in server configuration file.");
2673 if (!options
.xauth_location
||
2674 (stat(options
.xauth_location
, &st
) == -1)) {
2675 packet_send_debug("No xauth program; cannot forward with spoofing.");
2678 if (options
.use_login
) {
2679 packet_send_debug("X11 forwarding disabled; "
2680 "not compatible with UseLogin=yes.");
2683 if (s
->display
!= NULL
) {
2684 debug("X11 display already set.");
2687 if (x11_create_display_inet(options
.x11_display_offset
,
2688 options
.x11_use_localhost
, s
->single_connection
,
2689 &s
->display_number
, &s
->x11_chanids
) == -1) {
2690 debug("x11_create_display_inet failed.");
2693 for (i
= 0; s
->x11_chanids
[i
] != -1; i
++) {
2694 channel_register_cleanup(s
->x11_chanids
[i
],
2695 session_close_single_x11
, 0);
2698 /* Set up a suitable value for the DISPLAY variable. */
2699 if (gethostname(hostname
, sizeof(hostname
)) < 0)
2700 fatal("gethostname: %.100s", strerror(errno
));
2702 * auth_display must be used as the displayname when the
2703 * authorization entry is added with xauth(1). This will be
2704 * different than the DISPLAY string for localhost displays.
2706 if (options
.x11_use_localhost
) {
2707 snprintf(display
, sizeof display
, "localhost:%u.%u",
2708 s
->display_number
, s
->screen
);
2709 snprintf(auth_display
, sizeof auth_display
, "unix:%u.%u",
2710 s
->display_number
, s
->screen
);
2711 s
->display
= xstrdup(display
);
2712 s
->auth_display
= xstrdup(auth_display
);
2714 #ifdef IPADDR_IN_DISPLAY
2716 struct in_addr my_addr
;
2718 he
= gethostbyname(hostname
);
2720 error("Can't get IP address for X11 DISPLAY.");
2721 packet_send_debug("Can't get IP address for X11 DISPLAY.");
2724 memcpy(&my_addr
, he
->h_addr_list
[0], sizeof(struct in_addr
));
2725 snprintf(display
, sizeof display
, "%.50s:%u.%u", inet_ntoa(my_addr
),
2726 s
->display_number
, s
->screen
);
2728 snprintf(display
, sizeof display
, "%.400s:%u.%u", hostname
,
2729 s
->display_number
, s
->screen
);
2731 s
->display
= xstrdup(display
);
2732 s
->auth_display
= xstrdup(display
);
2739 do_authenticated2(Authctxt
*authctxt
)
2741 server_loop2(authctxt
);
2745 do_cleanup(Authctxt
*authctxt
)
2747 static int called
= 0;
2749 debug("do_cleanup");
2751 /* no cleanup if we're in the child for login shell */
2755 /* avoid double cleanup */
2760 if (authctxt
== NULL
)
2764 if (options
.use_pam
) {
2766 sshpam_thread_cleanup();
2770 if (!authctxt
->authenticated
)
2774 if (options
.kerberos_ticket_cleanup
&&
2776 krb5_cleanup_proc(authctxt
);
2780 if (compat20
&& options
.gss_cleanup_creds
)
2781 ssh_gssapi_cleanup_creds();
2784 /* remove agent socket */
2785 auth_sock_cleanup_proc(authctxt
->pw
);
2788 * Cleanup ptys/utmp only if privsep is disabled,
2789 * or if running in monitor.
2791 if (!use_privsep
|| mm_is_monitor())
2792 session_destroy_all(session_pty_cleanup2
);