1 /* $OpenBSD: serverloop.c,v 1.164 2012/12/07 01:51:35 dtucker Exp $ */
4 * Author: Tatu Ylonen <ylo@cs.hut.fi>
5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
7 * Server main loop for handling the interactive session.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
15 * SSH2 support by Markus Friedl.
16 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
41 #include <sys/types.h>
42 #include <sys/param.h>
44 #include <sys/socket.h>
45 #ifdef HAVE_SYS_TIME_H
46 # include <sys/time.h>
49 #include <netinet/in.h>
60 #include "openbsd-compat/sys-queue.h"
79 #include "auth-options.h"
80 #include "serverloop.h"
84 extern ServerOptions options;
88 extern Authctxt *the_authctxt;
89 extern int use_privsep;
91 static Buffer stdin_buffer; /* Buffer for stdin data. */
92 static Buffer stdout_buffer; /* Buffer for stdout data. */
93 static Buffer stderr_buffer; /* Buffer for stderr data. */
94 static int fdin; /* Descriptor for stdin (for writing) */
95 static int fdout; /* Descriptor for stdout (for reading);
96 May be same number as fdin. */
97 static int fderr; /* Descriptor for stderr. May be -1. */
98 static long stdin_bytes = 0; /* Number of bytes written to stdin. */
99 static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
100 static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
101 static long fdout_bytes = 0; /* Number of stdout bytes read from program. */
102 static int stdin_eof = 0; /* EOF message received from client. */
103 static int fdout_eof = 0; /* EOF encountered reading from fdout. */
104 static int fderr_eof = 0; /* EOF encountered readung from fderr. */
105 static int fdin_is_tty = 0; /* fdin points to a tty. */
106 static int connection_in; /* Connection to client (input). */
107 static int connection_out; /* Connection to client (output). */
108 static int connection_closed = 0; /* Connection to client closed. */
109 static u_int buffer_high; /* "Soft" max buffer size. */
110 static int no_more_sessions = 0; /* Disallow further sessions. */
113 * This SIGCHLD kludge is used to detect when the child exits. The server
114 * will exit after that, as soon as forwarded connections have terminated.
117 static volatile sig_atomic_t child_terminated = 0; /* The child has terminated. */
119 /* Cleanup on signals (!use_privsep case only) */
120 static volatile sig_atomic_t received_sigterm = 0;
123 static void server_init_dispatch(void);
126 * we write to this pipe if a SIGCHLD is caught in order to avoid
127 * the race between select() and child_terminated
129 static int notify_pipe[2];
133 if (pipe(notify_pipe) < 0) {
134 error("pipe(notify_pipe) failed %s", strerror(errno));
135 } else if ((fcntl(notify_pipe[0], F_SETFD, FD_CLOEXEC) == -1) ||
136 (fcntl(notify_pipe[1], F_SETFD, FD_CLOEXEC) == -1)) {
137 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
138 close(notify_pipe[0]);
139 close(notify_pipe[1]);
141 set_nonblock(notify_pipe[0]);
142 set_nonblock(notify_pipe[1]);
145 notify_pipe[0] = -1; /* read end */
146 notify_pipe[1] = -1; /* write end */
151 if (notify_pipe[1] != -1)
152 write(notify_pipe[1], "", 1);
155 notify_prepare(fd_set *readset)
157 if (notify_pipe[0] != -1)
158 FD_SET(notify_pipe[0], readset);
161 notify_done(fd_set *readset)
165 if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
166 while (read(notify_pipe[0], &c, 1) != -1)
167 debug2("notify_done: reading");
172 sigchld_handler(int sig)
174 int save_errno = errno;
175 child_terminated = 1;
177 mysignal(SIGCHLD, sigchld_handler);
185 sigterm_handler(int sig)
187 received_sigterm = sig;
191 * Make packets from buffered stderr data, and buffer it for sending
195 make_packets_from_stderr_data(void)
199 /* Send buffered stderr data to the client. */
200 while (buffer_len(&stderr_buffer) > 0 &&
201 packet_not_very_much_data_to_write()) {
202 len = buffer_len(&stderr_buffer);
203 if (packet_is_interactive()) {
207 /* Keep the packets at reasonable size. */
208 if (len > packet_get_maxsize())
209 len = packet_get_maxsize();
211 packet_start(SSH_SMSG_STDERR_DATA);
212 packet_put_string(buffer_ptr(&stderr_buffer), len);
214 buffer_consume(&stderr_buffer, len);
220 * Make packets from buffered stdout data, and buffer it for sending to the
224 make_packets_from_stdout_data(void)
228 /* Send buffered stdout data to the client. */
229 while (buffer_len(&stdout_buffer) > 0 &&
230 packet_not_very_much_data_to_write()) {
231 len = buffer_len(&stdout_buffer);
232 if (packet_is_interactive()) {
236 /* Keep the packets at reasonable size. */
237 if (len > packet_get_maxsize())
238 len = packet_get_maxsize();
240 packet_start(SSH_SMSG_STDOUT_DATA);
241 packet_put_string(buffer_ptr(&stdout_buffer), len);
243 buffer_consume(&stdout_buffer, len);
249 client_alive_check(void)
253 /* timeout, check to see how many we have had */
254 if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
255 logit("Timeout, client not responding.");
260 * send a bogus global/channel request with "wantreply",
261 * we should get back a failure
263 if ((channel_id = channel_find_open()) == -1) {
264 packet_start(SSH2_MSG_GLOBAL_REQUEST);
265 packet_put_cstring("keepalive@openssh.com");
266 packet_put_char(1); /* boolean: want reply */
268 channel_request_start(channel_id, "keepalive@openssh.com", 1);
274 * Sleep in select() until we can do something. This will initialize the
275 * select masks. Upon return, the masks will indicate which descriptors
276 * have data or can accept data. Optionally, a maximum time can be specified
277 * for the duration of the wait (0 = infinite).
280 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
281 u_int *nallocp, u_int max_time_milliseconds)
283 struct timeval tv, *tvp;
285 time_t minwait_secs = 0;
286 int client_alive_scheduled = 0;
287 int program_alive_scheduled = 0;
289 /* Allocate and update select() masks for channel descriptors. */
290 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp,
293 if (minwait_secs != 0)
294 max_time_milliseconds = MIN(max_time_milliseconds,
295 (u_int)minwait_secs * 1000);
298 * if using client_alive, set the max timeout accordingly,
299 * and indicate that this particular timeout was for client
300 * alive by setting the client_alive_scheduled flag.
302 * this could be randomized somewhat to make traffic
303 * analysis more difficult, but we're not doing it yet.
306 max_time_milliseconds == 0 && options.client_alive_interval) {
307 client_alive_scheduled = 1;
308 max_time_milliseconds = options.client_alive_interval * 1000;
313 /* wrong: bad condition XXX */
314 if (channel_not_very_much_buffered_data())
316 FD_SET(connection_in, *readsetp);
319 * Read packets from the client unless we have too much
320 * buffered stdin or channel data.
322 if (buffer_len(&stdin_buffer) < buffer_high &&
323 channel_not_very_much_buffered_data())
324 FD_SET(connection_in, *readsetp);
326 * If there is not too much data already buffered going to
327 * the client, try to get some more data from the program.
329 if (packet_not_very_much_data_to_write()) {
330 program_alive_scheduled = child_terminated;
332 FD_SET(fdout, *readsetp);
334 FD_SET(fderr, *readsetp);
337 * If we have buffered data, try to write some of that data
340 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
341 FD_SET(fdin, *writesetp);
343 notify_prepare(*readsetp);
346 * If we have buffered packet data going to the client, mark that
349 if (packet_have_data_to_write())
350 FD_SET(connection_out, *writesetp);
353 * If child has terminated and there is enough buffer space to read
354 * from it, then read as much as is available and exit.
356 if (child_terminated && packet_not_very_much_data_to_write())
357 if (max_time_milliseconds == 0 || client_alive_scheduled)
358 max_time_milliseconds = 100;
360 if (max_time_milliseconds == 0)
363 tv.tv_sec = max_time_milliseconds / 1000;
364 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
368 /* Wait for something to happen, or the timeout to expire. */
369 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
372 memset(*readsetp, 0, *nallocp);
373 memset(*writesetp, 0, *nallocp);
375 error("select: %.100s", strerror(errno));
377 if (ret == 0 && client_alive_scheduled)
378 client_alive_check();
379 if (!compat20 && program_alive_scheduled && fdin_is_tty) {
381 FD_SET(fdout, *readsetp);
383 FD_SET(fderr, *readsetp);
387 notify_done(*readsetp);
391 * Processes input from the client and the program. Input data is stored
392 * in buffers and processed later.
395 process_input(fd_set *readset)
400 /* Read and buffer any input data from the client. */
401 if (FD_ISSET(connection_in, readset)) {
403 len = roaming_read(connection_in, buf, sizeof(buf), &cont);
407 verbose("Connection closed by %.100s",
408 get_remote_ipaddr());
409 connection_closed = 1;
413 } else if (len < 0) {
414 if (errno != EINTR && errno != EAGAIN &&
415 errno != EWOULDBLOCK) {
416 verbose("Read error from remote host "
418 get_remote_ipaddr(), strerror(errno));
422 /* Buffer any received data. */
423 packet_process_incoming(buf, len);
429 /* Read and buffer any available stdout data from the program. */
430 if (!fdout_eof && FD_ISSET(fdout, readset)) {
432 len = read(fdout, buf, sizeof(buf));
433 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
434 errno == EWOULDBLOCK) && !child_terminated))) {
437 } else if (len <= 0) {
439 } else if ((!isatty(fdout) && len <= 0) ||
440 (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
444 buffer_append(&stdout_buffer, buf, len);
448 /* Read and buffer any available stderr data from the program. */
449 if (!fderr_eof && FD_ISSET(fderr, readset)) {
451 len = read(fderr, buf, sizeof(buf));
452 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
453 errno == EWOULDBLOCK) && !child_terminated))) {
456 } else if (len <= 0) {
458 } else if ((!isatty(fderr) && len <= 0) ||
459 (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
463 buffer_append(&stderr_buffer, buf, len);
469 * Sends data from internal buffers to client program stdin.
472 process_output(fd_set *writeset)
479 /* Write buffered data to program stdin. */
480 if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
481 data = buffer_ptr(&stdin_buffer);
482 dlen = buffer_len(&stdin_buffer);
483 len = write(fdin, data, dlen);
485 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) {
487 } else if (len <= 0) {
491 shutdown(fdin, SHUT_WR); /* We will no longer send. */
494 /* Successful write. */
495 if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
496 tcgetattr(fdin, &tio) == 0 &&
497 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
499 * Simulate echo to reduce the impact of
502 packet_send_ignore(len);
505 /* Consume the data from the buffer. */
506 buffer_consume(&stdin_buffer, len);
507 /* Update the count of bytes written to the program. */
511 /* Send any buffered packet data to the client. */
512 if (FD_ISSET(connection_out, writeset))
517 * Wait until all buffered output has been sent to the client.
518 * This is used when the program terminates.
523 /* Send any buffered stdout data to the client. */
524 if (buffer_len(&stdout_buffer) > 0) {
525 packet_start(SSH_SMSG_STDOUT_DATA);
526 packet_put_string(buffer_ptr(&stdout_buffer),
527 buffer_len(&stdout_buffer));
529 /* Update the count of sent bytes. */
530 stdout_bytes += buffer_len(&stdout_buffer);
532 /* Send any buffered stderr data to the client. */
533 if (buffer_len(&stderr_buffer) > 0) {
534 packet_start(SSH_SMSG_STDERR_DATA);
535 packet_put_string(buffer_ptr(&stderr_buffer),
536 buffer_len(&stderr_buffer));
538 /* Update the count of sent bytes. */
539 stderr_bytes += buffer_len(&stderr_buffer);
541 /* Wait until all buffered data has been written to the client. */
546 process_buffered_input_packets(void)
548 dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
552 * Performs the interactive session. This handles data transmission between
553 * the client and the program. Note that the notion of stdin, stdout, and
554 * stderr in this function is sort of reversed: this function writes to
555 * stdin (of the child program), and reads from stdout and stderr (of the
559 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
561 fd_set *readset = NULL, *writeset = NULL;
564 int wait_status; /* Status returned by wait(). */
565 pid_t wait_pid; /* pid returned by wait(). */
566 int waiting_termination = 0; /* Have displayed waiting close message. */
567 u_int max_time_milliseconds;
568 u_int previous_stdout_buffer_bytes;
569 u_int stdout_buffer_bytes;
572 debug("Entering interactive session.");
574 /* Initialize the SIGCHLD kludge. */
575 child_terminated = 0;
576 mysignal(SIGCHLD, sigchld_handler);
579 signal(SIGTERM, sigterm_handler);
580 signal(SIGINT, sigterm_handler);
581 signal(SIGQUIT, sigterm_handler);
584 /* Initialize our global variables. */
592 /* we don't have stderr for interactive terminal sessions, see below */
596 if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
599 connection_in = packet_get_connection_in();
600 connection_out = packet_get_connection_out();
604 previous_stdout_buffer_bytes = 0;
606 /* Set approximate I/O buffer size. */
607 if (packet_is_interactive())
610 buffer_high = 64 * 1024;
613 /* Initialize max_fd to the maximum of the known file descriptors. */
614 max_fd = MAX(connection_in, connection_out);
615 max_fd = MAX(max_fd, fdin);
616 max_fd = MAX(max_fd, fdout);
618 max_fd = MAX(max_fd, fderr);
621 /* Initialize Initialize buffers. */
622 buffer_init(&stdin_buffer);
623 buffer_init(&stdout_buffer);
624 buffer_init(&stderr_buffer);
627 * If we have no separate fderr (which is the case when we have a pty
628 * - there we cannot make difference between data sent to stdout and
629 * stderr), indicate that we have seen an EOF from stderr. This way
630 * we don't need to check the descriptor everywhere.
635 server_init_dispatch();
637 /* Main loop of the server for the interactive session mode. */
640 /* Process buffered packets from the client. */
641 process_buffered_input_packets();
644 * If we have received eof, and there is no more pending
645 * input data, cause a real eof by closing fdin.
647 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
651 shutdown(fdin, SHUT_WR); /* We will no longer send. */
654 /* Make packets from buffered stderr data to send to the client. */
655 make_packets_from_stderr_data();
658 * Make packets from buffered stdout data to send to the
659 * client. If there is very little to send, this arranges to
660 * not send them now, but to wait a short while to see if we
661 * are getting more data. This is necessary, as some systems
662 * wake up readers from a pty after each separate character.
664 max_time_milliseconds = 0;
665 stdout_buffer_bytes = buffer_len(&stdout_buffer);
666 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
667 stdout_buffer_bytes != previous_stdout_buffer_bytes) {
668 /* try again after a while */
669 max_time_milliseconds = 10;
672 make_packets_from_stdout_data();
674 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
676 /* Send channel data to the client. */
677 if (packet_not_very_much_data_to_write())
678 channel_output_poll();
681 * Bail out of the loop if the program has closed its output
682 * descriptors, and we have no more data to send to the
683 * client, and there is no pending buffered data.
685 if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
686 buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
687 if (!channel_still_open())
689 if (!waiting_termination) {
690 const char *s = "Waiting for forwarded connections to terminate...\r\n";
692 waiting_termination = 1;
693 buffer_append(&stderr_buffer, s, strlen(s));
695 /* Display list of open channels. */
696 cp = channel_open_message();
697 buffer_append(&stderr_buffer, cp, strlen(cp));
701 max_fd = MAX(connection_in, connection_out);
702 max_fd = MAX(max_fd, fdin);
703 max_fd = MAX(max_fd, fdout);
704 max_fd = MAX(max_fd, fderr);
705 max_fd = MAX(max_fd, notify_pipe[0]);
707 /* Sleep in select() until we can do something. */
708 wait_until_can_do_something(&readset, &writeset, &max_fd,
709 &nalloc, max_time_milliseconds);
711 if (received_sigterm) {
712 logit("Exiting on signal %d", (int)received_sigterm);
713 /* Clean up sessions, utmp, etc. */
717 /* Process any channel events. */
718 channel_after_select(readset, writeset);
720 /* Process input from the client and from program stdout/stderr. */
721 process_input(readset);
723 /* Process output to the client and to program stdin. */
724 process_output(writeset);
731 /* Cleanup and termination code. */
733 /* Wait until all output has been sent to the client. */
736 debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
737 stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
739 /* Free and clear the buffers. */
740 buffer_free(&stdin_buffer);
741 buffer_free(&stdout_buffer);
742 buffer_free(&stderr_buffer);
744 /* Close the file descriptors. */
759 /* We no longer want our SIGCHLD handler to be called. */
760 mysignal(SIGCHLD, SIG_DFL);
762 while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
764 packet_disconnect("wait: %.100s", strerror(errno));
766 error("Strange, wait returned pid %ld, expected %ld",
767 (long)wait_pid, (long)pid);
769 /* Check if it exited normally. */
770 if (WIFEXITED(wait_status)) {
771 /* Yes, normal exit. Get exit status and send it to the client. */
772 debug("Command exited with status %d.", WEXITSTATUS(wait_status));
773 packet_start(SSH_SMSG_EXITSTATUS);
774 packet_put_int(WEXITSTATUS(wait_status));
779 * Wait for exit confirmation. Note that there might be
780 * other packets coming before it; however, the program has
781 * already died so we just ignore them. The client is
782 * supposed to respond with the confirmation when it receives
786 type = packet_read();
788 while (type != SSH_CMSG_EXIT_CONFIRMATION);
790 debug("Received exit confirmation.");
793 /* Check if the program terminated due to a signal. */
794 if (WIFSIGNALED(wait_status))
795 packet_disconnect("Command terminated on signal %d.",
796 WTERMSIG(wait_status));
798 /* Some weird exit cause. Just exit. */
799 packet_disconnect("wait returned status %04x.", wait_status);
804 collect_children(void)
810 /* block SIGCHLD while we check for dead children */
812 sigaddset(&nset, SIGCHLD);
813 sigprocmask(SIG_BLOCK, &nset, &oset);
814 if (child_terminated) {
815 debug("Received SIGCHLD.");
816 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
817 (pid < 0 && errno == EINTR))
819 session_close_by_pid(pid, status);
820 child_terminated = 0;
822 sigprocmask(SIG_SETMASK, &oset, NULL);
826 server_loop2(Authctxt *authctxt)
828 fd_set *readset = NULL, *writeset = NULL;
829 int rekeying = 0, max_fd, nalloc = 0;
831 debug("Entering interactive session for SSH2.");
833 mysignal(SIGCHLD, sigchld_handler);
834 child_terminated = 0;
835 connection_in = packet_get_connection_in();
836 connection_out = packet_get_connection_out();
839 signal(SIGTERM, sigterm_handler);
840 signal(SIGINT, sigterm_handler);
841 signal(SIGQUIT, sigterm_handler);
846 max_fd = MAX(connection_in, connection_out);
847 max_fd = MAX(max_fd, notify_pipe[0]);
849 server_init_dispatch();
852 process_buffered_input_packets();
854 rekeying = (xxx_kex != NULL && !xxx_kex->done);
856 if (!rekeying && packet_not_very_much_data_to_write())
857 channel_output_poll();
858 wait_until_can_do_something(&readset, &writeset, &max_fd,
861 if (received_sigterm) {
862 logit("Exiting on signal %d", (int)received_sigterm);
863 /* Clean up sessions, utmp, etc. */
869 channel_after_select(readset, writeset);
870 if (packet_need_rekeying()) {
871 debug("need rekeying");
873 kex_send_kexinit(xxx_kex);
876 process_input(readset);
877 if (connection_closed)
879 process_output(writeset);
888 /* free all channels, no more reads and writes */
891 /* free remaining sessions, e.g. remove wtmp entries */
892 session_destroy_all(NULL);
896 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
898 debug("Got %d/%u for keepalive", type, seq);
900 * reset timeout, since we got a sane answer from the client.
901 * even if this was generated by something other than
902 * the bogus CHANNEL_REQUEST we send for keepalives.
904 packet_set_alive_timeouts(0);
908 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
913 /* Stdin data from the client. Append it to the buffer. */
914 /* Ignore any data if the client has closed stdin. */
917 data = packet_get_string(&data_len);
919 buffer_append(&stdin_buffer, data, data_len);
920 memset(data, 0, data_len);
925 server_input_eof(int type, u_int32_t seq, void *ctxt)
928 * Eof from the client. The stdin descriptor to the
929 * program will be closed when all buffered data has
932 debug("EOF received for stdin.");
938 server_input_window_size(int type, u_int32_t seq, void *ctxt)
940 u_int row = packet_get_int();
941 u_int col = packet_get_int();
942 u_int xpixel = packet_get_int();
943 u_int ypixel = packet_get_int();
945 debug("Window change received.");
948 pty_change_window_size(fdin, row, col, xpixel, ypixel);
952 server_request_direct_tcpip(void)
955 char *target, *originator;
956 u_short target_port, originator_port;
958 target = packet_get_string(NULL);
959 target_port = packet_get_int();
960 originator = packet_get_string(NULL);
961 originator_port = packet_get_int();
964 debug("server_request_direct_tcpip: originator %s port %d, target %s "
965 "port %d", originator, originator_port, target, target_port);
967 /* XXX fine grained permissions */
968 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
969 !no_port_forwarding_flag) {
970 c = channel_connect_to(target, target_port,
971 "direct-tcpip", "direct-tcpip");
973 logit("refused local port forward: "
974 "originator %s port %d, target %s port %d",
975 originator, originator_port, target, target_port);
985 server_request_tun(void)
991 mode = packet_get_int();
993 case SSH_TUNMODE_POINTOPOINT:
994 case SSH_TUNMODE_ETHERNET:
997 packet_send_debug("Unsupported tunnel device mode.");
1000 if ((options.permit_tun & mode) == 0) {
1001 packet_send_debug("Server has rejected tunnel device "
1006 tun = packet_get_int();
1007 if (forced_tun_device != -1) {
1008 if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1010 tun = forced_tun_device;
1012 sock = tun_open(tun, mode);
1015 if (options.hpn_disabled)
1016 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1017 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
1020 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1021 options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0,
1024 #if defined(SSH_TUN_FILTER)
1025 if (mode == SSH_TUNMODE_POINTOPOINT)
1026 channel_register_filter(c->self, sys_tun_infilter,
1027 sys_tun_outfilter, NULL, NULL);
1032 packet_send_debug("Failed to open the tunnel device.");
1037 server_request_session(void)
1041 debug("input_session_request");
1044 if (no_more_sessions) {
1045 packet_disconnect("Possible attack: attempt to open a session "
1046 "after additional sessions disabled");
1050 * A server session has no fd to read or write until a
1051 * CHANNEL_REQUEST for a shell is made, so we set the type to
1052 * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all
1053 * CHANNEL_REQUEST messages is registered.
1055 c = channel_new("session", SSH_CHANNEL_LARVAL,
1056 -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1057 0, "server-session", 1);
1058 if (!options.hpn_disabled && options.tcp_rcv_buf_poll)
1059 c->dynamic_window = 1;
1060 if (session_open(the_authctxt, c->self) != 1) {
1061 debug("session open failed, free channel %d", c->self);
1065 channel_register_cleanup(c->self, session_close_by_channel, 0);
1070 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1075 u_int rmaxpack, rwindow, len;
1077 ctype = packet_get_string(&len);
1078 rchan = packet_get_int();
1079 rwindow = packet_get_int();
1080 rmaxpack = packet_get_int();
1082 debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1083 ctype, rchan, rwindow, rmaxpack);
1085 if (strcmp(ctype, "session") == 0) {
1086 c = server_request_session();
1087 } else if (strcmp(ctype, "direct-tcpip") == 0) {
1088 c = server_request_direct_tcpip();
1089 } else if (strcmp(ctype, "tun@openssh.com") == 0) {
1090 c = server_request_tun();
1093 debug("server_input_channel_open: confirm %s", ctype);
1094 c->remote_id = rchan;
1095 c->remote_window = rwindow;
1096 c->remote_maxpacket = rmaxpack;
1097 if (c->type != SSH_CHANNEL_CONNECTING) {
1098 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1099 packet_put_int(c->remote_id);
1100 packet_put_int(c->self);
1101 packet_put_int(c->local_window);
1102 packet_put_int(c->local_maxpacket);
1106 debug("server_input_channel_open: failure %s", ctype);
1107 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1108 packet_put_int(rchan);
1109 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1110 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1111 packet_put_cstring("open failed");
1112 packet_put_cstring("");
1120 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1124 int success = 0, allocated_listen_port = 0;
1126 rtype = packet_get_string(NULL);
1127 want_reply = packet_get_char();
1128 debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1130 /* -R style forwarding */
1131 if (strcmp(rtype, "tcpip-forward") == 0) {
1133 char *listen_address;
1134 u_short listen_port;
1136 pw = the_authctxt->pw;
1137 if (pw == NULL || !the_authctxt->valid)
1138 fatal("server_input_global_request: no/invalid user");
1139 listen_address = packet_get_string(NULL);
1140 listen_port = (u_short)packet_get_int();
1141 debug("server_input_global_request: tcpip-forward listen %s port %d",
1142 listen_address, listen_port);
1144 /* check permissions */
1145 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
1146 no_port_forwarding_flag ||
1147 (!want_reply && listen_port == 0)
1148 #ifndef NO_IPPORT_RESERVED_CONCEPT
1149 || (listen_port != 0 && listen_port < IPPORT_RESERVED &&
1154 packet_send_debug("Server has disabled port forwarding.");
1156 /* Start listening on the port */
1157 success = channel_setup_remote_fwd_listener(
1158 listen_address, listen_port,
1159 &allocated_listen_port, options.gateway_ports);
1161 xfree(listen_address);
1162 } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1163 char *cancel_address;
1164 u_short cancel_port;
1166 cancel_address = packet_get_string(NULL);
1167 cancel_port = (u_short)packet_get_int();
1168 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1169 cancel_address, cancel_port);
1171 success = channel_cancel_rport_listener(cancel_address,
1173 xfree(cancel_address);
1174 } else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
1175 no_more_sessions = 1;
1179 packet_start(success ?
1180 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1181 if (success && allocated_listen_port > 0)
1182 packet_put_int(allocated_listen_port);
1184 packet_write_wait();
1190 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1193 int id, reply, success = 0;
1196 id = packet_get_int();
1197 rtype = packet_get_string(NULL);
1198 reply = packet_get_char();
1200 debug("server_input_channel_req: channel %d request %s reply %d",
1203 if ((c = channel_lookup(id)) == NULL)
1204 packet_disconnect("server_input_channel_req: "
1205 "unknown channel %d", id);
1206 if (!strcmp(rtype, "eow@openssh.com")) {
1209 } else if ((c->type == SSH_CHANNEL_LARVAL ||
1210 c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
1211 success = session_input_channel_req(c, rtype);
1213 packet_start(success ?
1214 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1215 packet_put_int(c->remote_id);
1222 server_init_dispatch_20(void)
1224 debug("server_init_dispatch_20");
1225 dispatch_init(&dispatch_protocol_error);
1226 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1227 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1228 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1229 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1230 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1231 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1232 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1233 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1234 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1235 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1237 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_alive);
1238 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1239 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1240 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1242 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1245 server_init_dispatch_13(void)
1247 debug("server_init_dispatch_13");
1248 dispatch_init(NULL);
1249 dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1250 dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1251 dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1252 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1253 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1254 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1255 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1256 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1257 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1260 server_init_dispatch_15(void)
1262 server_init_dispatch_13();
1263 debug("server_init_dispatch_15");
1264 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1265 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1268 server_init_dispatch(void)
1271 server_init_dispatch_20();
1273 server_init_dispatch_13();
1275 server_init_dispatch_15();