1 /* $OpenBSD: serverloop.c,v 1.160 2011/05/15 08:09:01 djm Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * Server main loop for handling the interactive session.
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
14 * SSH2 support by Markus Friedl.
15 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 #include <sys/types.h>
41 #include <sys/param.h>
43 #include <sys/socket.h>
44 #ifdef HAVE_SYS_TIME_H
45 # include <sys/time.h>
48 #include <netinet/in.h>
59 #include "openbsd-compat/sys-queue.h"
78 #include "auth-options.h"
79 #include "serverloop.h"
83 extern ServerOptions options;
87 extern Authctxt *the_authctxt;
88 extern int use_privsep;
90 static Buffer stdin_buffer; /* Buffer for stdin data. */
91 static Buffer stdout_buffer; /* Buffer for stdout data. */
92 static Buffer stderr_buffer; /* Buffer for stderr data. */
93 static int fdin; /* Descriptor for stdin (for writing) */
94 static int fdout; /* Descriptor for stdout (for reading);
95 May be same number as fdin. */
96 static int fderr; /* Descriptor for stderr. May be -1. */
97 static long stdin_bytes = 0; /* Number of bytes written to stdin. */
98 static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
99 static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
100 static long fdout_bytes = 0; /* Number of stdout bytes read from program. */
101 static int stdin_eof = 0; /* EOF message received from client. */
102 static int fdout_eof = 0; /* EOF encountered reading from fdout. */
103 static int fderr_eof = 0; /* EOF encountered readung from fderr. */
104 static int fdin_is_tty = 0; /* fdin points to a tty. */
105 static int connection_in; /* Connection to client (input). */
106 static int connection_out; /* Connection to client (output). */
107 static int connection_closed = 0; /* Connection to client closed. */
108 static u_int buffer_high; /* "Soft" max buffer size. */
109 static int no_more_sessions = 0; /* Disallow further sessions. */
112 * This SIGCHLD kludge is used to detect when the child exits. The server
113 * will exit after that, as soon as forwarded connections have terminated.
116 static volatile sig_atomic_t child_terminated = 0; /* The child has terminated. */
118 /* Cleanup on signals (!use_privsep case only) */
119 static volatile sig_atomic_t received_sigterm = 0;
122 static void server_init_dispatch(void);
125 * we write to this pipe if a SIGCHLD is caught in order to avoid
126 * the race between select() and child_terminated
128 static int notify_pipe[2];
132 if (pipe(notify_pipe) < 0) {
133 error("pipe(notify_pipe) failed %s", strerror(errno));
134 } else if ((fcntl(notify_pipe[0], F_SETFD, FD_CLOEXEC) == -1) ||
135 (fcntl(notify_pipe[1], F_SETFD, FD_CLOEXEC) == -1)) {
136 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
137 close(notify_pipe[0]);
138 close(notify_pipe[1]);
140 set_nonblock(notify_pipe[0]);
141 set_nonblock(notify_pipe[1]);
144 notify_pipe[0] = -1; /* read end */
145 notify_pipe[1] = -1; /* write end */
150 if (notify_pipe[1] != -1)
151 write(notify_pipe[1], "", 1);
154 notify_prepare(fd_set *readset)
156 if (notify_pipe[0] != -1)
157 FD_SET(notify_pipe[0], readset);
160 notify_done(fd_set *readset)
164 if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
165 while (read(notify_pipe[0], &c, 1) != -1)
166 debug2("notify_done: reading");
171 sigchld_handler(int sig)
173 int save_errno = errno;
174 child_terminated = 1;
176 mysignal(SIGCHLD, sigchld_handler);
184 sigterm_handler(int sig)
186 received_sigterm = sig;
190 * Make packets from buffered stderr data, and buffer it for sending
194 make_packets_from_stderr_data(void)
198 /* Send buffered stderr data to the client. */
199 while (buffer_len(&stderr_buffer) > 0 &&
200 packet_not_very_much_data_to_write()) {
201 len = buffer_len(&stderr_buffer);
202 if (packet_is_interactive()) {
206 /* Keep the packets at reasonable size. */
207 if (len > packet_get_maxsize())
208 len = packet_get_maxsize();
210 packet_start(SSH_SMSG_STDERR_DATA);
211 packet_put_string(buffer_ptr(&stderr_buffer), len);
213 buffer_consume(&stderr_buffer, len);
219 * Make packets from buffered stdout data, and buffer it for sending to the
223 make_packets_from_stdout_data(void)
227 /* Send buffered stdout data to the client. */
228 while (buffer_len(&stdout_buffer) > 0 &&
229 packet_not_very_much_data_to_write()) {
230 len = buffer_len(&stdout_buffer);
231 if (packet_is_interactive()) {
235 /* Keep the packets at reasonable size. */
236 if (len > packet_get_maxsize())
237 len = packet_get_maxsize();
239 packet_start(SSH_SMSG_STDOUT_DATA);
240 packet_put_string(buffer_ptr(&stdout_buffer), len);
242 buffer_consume(&stdout_buffer, len);
248 client_alive_check(void)
252 /* timeout, check to see how many we have had */
253 if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
254 logit("Timeout, client not responding.");
259 * send a bogus global/channel request with "wantreply",
260 * we should get back a failure
262 if ((channel_id = channel_find_open()) == -1) {
263 packet_start(SSH2_MSG_GLOBAL_REQUEST);
264 packet_put_cstring("keepalive@openssh.com");
265 packet_put_char(1); /* boolean: want reply */
267 channel_request_start(channel_id, "keepalive@openssh.com", 1);
273 * Sleep in select() until we can do something. This will initialize the
274 * select masks. Upon return, the masks will indicate which descriptors
275 * have data or can accept data. Optionally, a maximum time can be specified
276 * for the duration of the wait (0 = infinite).
279 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
280 u_int *nallocp, u_int max_time_milliseconds)
282 struct timeval tv, *tvp;
284 int client_alive_scheduled = 0;
285 int program_alive_scheduled = 0;
288 * if using client_alive, set the max timeout accordingly,
289 * and indicate that this particular timeout was for client
290 * alive by setting the client_alive_scheduled flag.
292 * this could be randomized somewhat to make traffic
293 * analysis more difficult, but we're not doing it yet.
296 max_time_milliseconds == 0 && options.client_alive_interval) {
297 client_alive_scheduled = 1;
298 max_time_milliseconds = options.client_alive_interval * 1000;
301 /* Allocate and update select() masks for channel descriptors. */
302 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0);
306 /* wrong: bad condition XXX */
307 if (channel_not_very_much_buffered_data())
309 FD_SET(connection_in, *readsetp);
312 * Read packets from the client unless we have too much
313 * buffered stdin or channel data.
315 if (buffer_len(&stdin_buffer) < buffer_high &&
316 channel_not_very_much_buffered_data())
317 FD_SET(connection_in, *readsetp);
319 * If there is not too much data already buffered going to
320 * the client, try to get some more data from the program.
322 if (packet_not_very_much_data_to_write()) {
323 program_alive_scheduled = child_terminated;
325 FD_SET(fdout, *readsetp);
327 FD_SET(fderr, *readsetp);
330 * If we have buffered data, try to write some of that data
333 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
334 FD_SET(fdin, *writesetp);
336 notify_prepare(*readsetp);
339 * If we have buffered packet data going to the client, mark that
342 if (packet_have_data_to_write())
343 FD_SET(connection_out, *writesetp);
346 * If child has terminated and there is enough buffer space to read
347 * from it, then read as much as is available and exit.
349 if (child_terminated && packet_not_very_much_data_to_write())
350 if (max_time_milliseconds == 0 || client_alive_scheduled)
351 max_time_milliseconds = 100;
353 if (max_time_milliseconds == 0)
356 tv.tv_sec = max_time_milliseconds / 1000;
357 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
361 /* Wait for something to happen, or the timeout to expire. */
362 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
365 memset(*readsetp, 0, *nallocp);
366 memset(*writesetp, 0, *nallocp);
368 error("select: %.100s", strerror(errno));
370 if (ret == 0 && client_alive_scheduled)
371 client_alive_check();
372 if (!compat20 && program_alive_scheduled && fdin_is_tty) {
374 FD_SET(fdout, *readsetp);
376 FD_SET(fderr, *readsetp);
380 notify_done(*readsetp);
384 * Processes input from the client and the program. Input data is stored
385 * in buffers and processed later.
388 process_input(fd_set *readset)
393 /* Read and buffer any input data from the client. */
394 if (FD_ISSET(connection_in, readset)) {
396 len = roaming_read(connection_in, buf, sizeof(buf), &cont);
400 verbose("Connection closed by %.100s",
401 get_remote_ipaddr());
402 connection_closed = 1;
406 } else if (len < 0) {
407 if (errno != EINTR && errno != EAGAIN &&
408 errno != EWOULDBLOCK) {
409 verbose("Read error from remote host "
411 get_remote_ipaddr(), strerror(errno));
415 /* Buffer any received data. */
416 packet_process_incoming(buf, len);
422 /* Read and buffer any available stdout data from the program. */
423 if (!fdout_eof && FD_ISSET(fdout, readset)) {
425 len = read(fdout, buf, sizeof(buf));
426 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
427 errno == EWOULDBLOCK) && !child_terminated))) {
430 } else if (len <= 0) {
432 } else if ((!isatty(fdout) && len <= 0) ||
433 (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
437 buffer_append(&stdout_buffer, buf, len);
441 /* Read and buffer any available stderr data from the program. */
442 if (!fderr_eof && FD_ISSET(fderr, readset)) {
444 len = read(fderr, buf, sizeof(buf));
445 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
446 errno == EWOULDBLOCK) && !child_terminated))) {
449 } else if (len <= 0) {
451 } else if ((!isatty(fderr) && len <= 0) ||
452 (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
456 buffer_append(&stderr_buffer, buf, len);
462 * Sends data from internal buffers to client program stdin.
465 process_output(fd_set *writeset)
472 /* Write buffered data to program stdin. */
473 if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
474 data = buffer_ptr(&stdin_buffer);
475 dlen = buffer_len(&stdin_buffer);
476 len = write(fdin, data, dlen);
478 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) {
480 } else if (len <= 0) {
484 shutdown(fdin, SHUT_WR); /* We will no longer send. */
487 /* Successful write. */
488 if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
489 tcgetattr(fdin, &tio) == 0 &&
490 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
492 * Simulate echo to reduce the impact of
495 packet_send_ignore(len);
498 /* Consume the data from the buffer. */
499 buffer_consume(&stdin_buffer, len);
500 /* Update the count of bytes written to the program. */
504 /* Send any buffered packet data to the client. */
505 if (FD_ISSET(connection_out, writeset))
510 * Wait until all buffered output has been sent to the client.
511 * This is used when the program terminates.
516 /* Send any buffered stdout data to the client. */
517 if (buffer_len(&stdout_buffer) > 0) {
518 packet_start(SSH_SMSG_STDOUT_DATA);
519 packet_put_string(buffer_ptr(&stdout_buffer),
520 buffer_len(&stdout_buffer));
522 /* Update the count of sent bytes. */
523 stdout_bytes += buffer_len(&stdout_buffer);
525 /* Send any buffered stderr data to the client. */
526 if (buffer_len(&stderr_buffer) > 0) {
527 packet_start(SSH_SMSG_STDERR_DATA);
528 packet_put_string(buffer_ptr(&stderr_buffer),
529 buffer_len(&stderr_buffer));
531 /* Update the count of sent bytes. */
532 stderr_bytes += buffer_len(&stderr_buffer);
534 /* Wait until all buffered data has been written to the client. */
539 process_buffered_input_packets(void)
541 dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
545 * Performs the interactive session. This handles data transmission between
546 * the client and the program. Note that the notion of stdin, stdout, and
547 * stderr in this function is sort of reversed: this function writes to
548 * stdin (of the child program), and reads from stdout and stderr (of the
552 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
554 fd_set *readset = NULL, *writeset = NULL;
557 int wait_status; /* Status returned by wait(). */
558 pid_t wait_pid; /* pid returned by wait(). */
559 int waiting_termination = 0; /* Have displayed waiting close message. */
560 u_int max_time_milliseconds;
561 u_int previous_stdout_buffer_bytes;
562 u_int stdout_buffer_bytes;
565 debug("Entering interactive session.");
567 /* Initialize the SIGCHLD kludge. */
568 child_terminated = 0;
569 mysignal(SIGCHLD, sigchld_handler);
572 signal(SIGTERM, sigterm_handler);
573 signal(SIGINT, sigterm_handler);
574 signal(SIGQUIT, sigterm_handler);
577 /* Initialize our global variables. */
585 /* we don't have stderr for interactive terminal sessions, see below */
589 if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
592 connection_in = packet_get_connection_in();
593 connection_out = packet_get_connection_out();
597 previous_stdout_buffer_bytes = 0;
599 /* Set approximate I/O buffer size. */
600 if (packet_is_interactive())
603 buffer_high = 64 * 1024;
606 /* Initialize max_fd to the maximum of the known file descriptors. */
607 max_fd = MAX(connection_in, connection_out);
608 max_fd = MAX(max_fd, fdin);
609 max_fd = MAX(max_fd, fdout);
611 max_fd = MAX(max_fd, fderr);
614 /* Initialize Initialize buffers. */
615 buffer_init(&stdin_buffer);
616 buffer_init(&stdout_buffer);
617 buffer_init(&stderr_buffer);
620 * If we have no separate fderr (which is the case when we have a pty
621 * - there we cannot make difference between data sent to stdout and
622 * stderr), indicate that we have seen an EOF from stderr. This way
623 * we don't need to check the descriptor everywhere.
628 server_init_dispatch();
630 /* Main loop of the server for the interactive session mode. */
633 /* Process buffered packets from the client. */
634 process_buffered_input_packets();
637 * If we have received eof, and there is no more pending
638 * input data, cause a real eof by closing fdin.
640 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
644 shutdown(fdin, SHUT_WR); /* We will no longer send. */
647 /* Make packets from buffered stderr data to send to the client. */
648 make_packets_from_stderr_data();
651 * Make packets from buffered stdout data to send to the
652 * client. If there is very little to send, this arranges to
653 * not send them now, but to wait a short while to see if we
654 * are getting more data. This is necessary, as some systems
655 * wake up readers from a pty after each separate character.
657 max_time_milliseconds = 0;
658 stdout_buffer_bytes = buffer_len(&stdout_buffer);
659 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
660 stdout_buffer_bytes != previous_stdout_buffer_bytes) {
661 /* try again after a while */
662 max_time_milliseconds = 10;
665 make_packets_from_stdout_data();
667 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
669 /* Send channel data to the client. */
670 if (packet_not_very_much_data_to_write())
671 channel_output_poll();
674 * Bail out of the loop if the program has closed its output
675 * descriptors, and we have no more data to send to the
676 * client, and there is no pending buffered data.
678 if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
679 buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
680 if (!channel_still_open())
682 if (!waiting_termination) {
683 const char *s = "Waiting for forwarded connections to terminate...\r\n";
685 waiting_termination = 1;
686 buffer_append(&stderr_buffer, s, strlen(s));
688 /* Display list of open channels. */
689 cp = channel_open_message();
690 buffer_append(&stderr_buffer, cp, strlen(cp));
694 max_fd = MAX(connection_in, connection_out);
695 max_fd = MAX(max_fd, fdin);
696 max_fd = MAX(max_fd, fdout);
697 max_fd = MAX(max_fd, fderr);
698 max_fd = MAX(max_fd, notify_pipe[0]);
700 /* Sleep in select() until we can do something. */
701 wait_until_can_do_something(&readset, &writeset, &max_fd,
702 &nalloc, max_time_milliseconds);
704 if (received_sigterm) {
705 logit("Exiting on signal %d", received_sigterm);
706 /* Clean up sessions, utmp, etc. */
710 /* Process any channel events. */
711 channel_after_select(readset, writeset);
713 /* Process input from the client and from program stdout/stderr. */
714 process_input(readset);
716 /* Process output to the client and to program stdin. */
717 process_output(writeset);
724 /* Cleanup and termination code. */
726 /* Wait until all output has been sent to the client. */
729 debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
730 stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
732 /* Free and clear the buffers. */
733 buffer_free(&stdin_buffer);
734 buffer_free(&stdout_buffer);
735 buffer_free(&stderr_buffer);
737 /* Close the file descriptors. */
752 /* We no longer want our SIGCHLD handler to be called. */
753 mysignal(SIGCHLD, SIG_DFL);
755 while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
757 packet_disconnect("wait: %.100s", strerror(errno));
759 error("Strange, wait returned pid %ld, expected %ld",
760 (long)wait_pid, (long)pid);
762 /* Check if it exited normally. */
763 if (WIFEXITED(wait_status)) {
764 /* Yes, normal exit. Get exit status and send it to the client. */
765 debug("Command exited with status %d.", WEXITSTATUS(wait_status));
766 packet_start(SSH_SMSG_EXITSTATUS);
767 packet_put_int(WEXITSTATUS(wait_status));
772 * Wait for exit confirmation. Note that there might be
773 * other packets coming before it; however, the program has
774 * already died so we just ignore them. The client is
775 * supposed to respond with the confirmation when it receives
779 type = packet_read();
781 while (type != SSH_CMSG_EXIT_CONFIRMATION);
783 debug("Received exit confirmation.");
786 /* Check if the program terminated due to a signal. */
787 if (WIFSIGNALED(wait_status))
788 packet_disconnect("Command terminated on signal %d.",
789 WTERMSIG(wait_status));
791 /* Some weird exit cause. Just exit. */
792 packet_disconnect("wait returned status %04x.", wait_status);
797 collect_children(void)
803 /* block SIGCHLD while we check for dead children */
805 sigaddset(&nset, SIGCHLD);
806 sigprocmask(SIG_BLOCK, &nset, &oset);
807 if (child_terminated) {
808 debug("Received SIGCHLD.");
809 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
810 (pid < 0 && errno == EINTR))
812 session_close_by_pid(pid, status);
813 child_terminated = 0;
815 sigprocmask(SIG_SETMASK, &oset, NULL);
819 server_loop2(Authctxt *authctxt)
821 fd_set *readset = NULL, *writeset = NULL;
822 int rekeying = 0, max_fd, nalloc = 0;
824 debug("Entering interactive session for SSH2.");
826 mysignal(SIGCHLD, sigchld_handler);
827 child_terminated = 0;
828 connection_in = packet_get_connection_in();
829 connection_out = packet_get_connection_out();
832 signal(SIGTERM, sigterm_handler);
833 signal(SIGINT, sigterm_handler);
834 signal(SIGQUIT, sigterm_handler);
839 max_fd = MAX(connection_in, connection_out);
840 max_fd = MAX(max_fd, notify_pipe[0]);
842 server_init_dispatch();
845 process_buffered_input_packets();
847 rekeying = (xxx_kex != NULL && !xxx_kex->done);
849 if (!rekeying && packet_not_very_much_data_to_write())
850 channel_output_poll();
851 wait_until_can_do_something(&readset, &writeset, &max_fd,
854 if (received_sigterm) {
855 logit("Exiting on signal %d", received_sigterm);
856 /* Clean up sessions, utmp, etc. */
862 channel_after_select(readset, writeset);
863 if (packet_need_rekeying()) {
864 debug("need rekeying");
866 kex_send_kexinit(xxx_kex);
869 process_input(readset);
870 if (connection_closed)
872 process_output(writeset);
881 /* free all channels, no more reads and writes */
884 /* free remaining sessions, e.g. remove wtmp entries */
885 session_destroy_all(NULL);
889 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
891 debug("Got %d/%u for keepalive", type, seq);
893 * reset timeout, since we got a sane answer from the client.
894 * even if this was generated by something other than
895 * the bogus CHANNEL_REQUEST we send for keepalives.
897 packet_set_alive_timeouts(0);
901 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
906 /* Stdin data from the client. Append it to the buffer. */
907 /* Ignore any data if the client has closed stdin. */
910 data = packet_get_string(&data_len);
912 buffer_append(&stdin_buffer, data, data_len);
913 memset(data, 0, data_len);
918 server_input_eof(int type, u_int32_t seq, void *ctxt)
921 * Eof from the client. The stdin descriptor to the
922 * program will be closed when all buffered data has
925 debug("EOF received for stdin.");
931 server_input_window_size(int type, u_int32_t seq, void *ctxt)
933 u_int row = packet_get_int();
934 u_int col = packet_get_int();
935 u_int xpixel = packet_get_int();
936 u_int ypixel = packet_get_int();
938 debug("Window change received.");
941 pty_change_window_size(fdin, row, col, xpixel, ypixel);
945 server_request_direct_tcpip(void)
948 char *target, *originator;
949 u_short target_port, originator_port;
951 target = packet_get_string(NULL);
952 target_port = packet_get_int();
953 originator = packet_get_string(NULL);
954 originator_port = packet_get_int();
957 debug("server_request_direct_tcpip: originator %s port %d, target %s "
958 "port %d", originator, originator_port, target, target_port);
960 /* XXX check permission */
961 c = channel_connect_to(target, target_port,
962 "direct-tcpip", "direct-tcpip");
971 server_request_tun(void)
977 mode = packet_get_int();
979 case SSH_TUNMODE_POINTOPOINT:
980 case SSH_TUNMODE_ETHERNET:
983 packet_send_debug("Unsupported tunnel device mode.");
986 if ((options.permit_tun & mode) == 0) {
987 packet_send_debug("Server has rejected tunnel device "
992 tun = packet_get_int();
993 if (forced_tun_device != -1) {
994 if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
996 tun = forced_tun_device;
998 sock = tun_open(tun, mode);
1001 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1002 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1004 #if defined(SSH_TUN_FILTER)
1005 if (mode == SSH_TUNMODE_POINTOPOINT)
1006 channel_register_filter(c->self, sys_tun_infilter,
1007 sys_tun_outfilter, NULL, NULL);
1012 packet_send_debug("Failed to open the tunnel device.");
1017 server_request_session(void)
1021 debug("input_session_request");
1024 if (no_more_sessions) {
1025 packet_disconnect("Possible attack: attempt to open a session "
1026 "after additional sessions disabled");
1030 * A server session has no fd to read or write until a
1031 * CHANNEL_REQUEST for a shell is made, so we set the type to
1032 * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all
1033 * CHANNEL_REQUEST messages is registered.
1035 c = channel_new("session", SSH_CHANNEL_LARVAL,
1036 -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1037 0, "server-session", 1);
1038 if (session_open(the_authctxt, c->self) != 1) {
1039 debug("session open failed, free channel %d", c->self);
1043 channel_register_cleanup(c->self, session_close_by_channel, 0);
1048 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1053 u_int rmaxpack, rwindow, len;
1055 ctype = packet_get_string(&len);
1056 rchan = packet_get_int();
1057 rwindow = packet_get_int();
1058 rmaxpack = packet_get_int();
1060 debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1061 ctype, rchan, rwindow, rmaxpack);
1063 if (strcmp(ctype, "session") == 0) {
1064 c = server_request_session();
1065 } else if (strcmp(ctype, "direct-tcpip") == 0) {
1066 c = server_request_direct_tcpip();
1067 } else if (strcmp(ctype, "tun@openssh.com") == 0) {
1068 c = server_request_tun();
1071 debug("server_input_channel_open: confirm %s", ctype);
1072 c->remote_id = rchan;
1073 c->remote_window = rwindow;
1074 c->remote_maxpacket = rmaxpack;
1075 if (c->type != SSH_CHANNEL_CONNECTING) {
1076 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1077 packet_put_int(c->remote_id);
1078 packet_put_int(c->self);
1079 packet_put_int(c->local_window);
1080 packet_put_int(c->local_maxpacket);
1084 debug("server_input_channel_open: failure %s", ctype);
1085 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1086 packet_put_int(rchan);
1087 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1088 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1089 packet_put_cstring("open failed");
1090 packet_put_cstring("");
1098 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1102 int success = 0, allocated_listen_port = 0;
1104 rtype = packet_get_string(NULL);
1105 want_reply = packet_get_char();
1106 debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1108 /* -R style forwarding */
1109 if (strcmp(rtype, "tcpip-forward") == 0) {
1111 char *listen_address;
1112 u_short listen_port;
1114 pw = the_authctxt->pw;
1115 if (pw == NULL || !the_authctxt->valid)
1116 fatal("server_input_global_request: no/invalid user");
1117 listen_address = packet_get_string(NULL);
1118 listen_port = (u_short)packet_get_int();
1119 debug("server_input_global_request: tcpip-forward listen %s port %d",
1120 listen_address, listen_port);
1122 /* check permissions */
1123 if (!options.allow_tcp_forwarding ||
1124 no_port_forwarding_flag ||
1125 (!want_reply && listen_port == 0)
1126 #ifndef NO_IPPORT_RESERVED_CONCEPT
1127 || (listen_port != 0 && listen_port < IPPORT_RESERVED &&
1132 packet_send_debug("Server has disabled port forwarding.");
1134 /* Start listening on the port */
1135 success = channel_setup_remote_fwd_listener(
1136 listen_address, listen_port,
1137 &allocated_listen_port, options.gateway_ports);
1139 xfree(listen_address);
1140 } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1141 char *cancel_address;
1142 u_short cancel_port;
1144 cancel_address = packet_get_string(NULL);
1145 cancel_port = (u_short)packet_get_int();
1146 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1147 cancel_address, cancel_port);
1149 success = channel_cancel_rport_listener(cancel_address,
1151 xfree(cancel_address);
1152 } else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
1153 no_more_sessions = 1;
1157 packet_start(success ?
1158 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1159 if (success && allocated_listen_port > 0)
1160 packet_put_int(allocated_listen_port);
1162 packet_write_wait();
1168 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1171 int id, reply, success = 0;
1174 id = packet_get_int();
1175 rtype = packet_get_string(NULL);
1176 reply = packet_get_char();
1178 debug("server_input_channel_req: channel %d request %s reply %d",
1181 if ((c = channel_lookup(id)) == NULL)
1182 packet_disconnect("server_input_channel_req: "
1183 "unknown channel %d", id);
1184 if (!strcmp(rtype, "eow@openssh.com")) {
1187 } else if ((c->type == SSH_CHANNEL_LARVAL ||
1188 c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
1189 success = session_input_channel_req(c, rtype);
1191 packet_start(success ?
1192 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1193 packet_put_int(c->remote_id);
1200 server_init_dispatch_20(void)
1202 debug("server_init_dispatch_20");
1203 dispatch_init(&dispatch_protocol_error);
1204 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1205 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1206 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1207 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1208 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1209 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1210 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1211 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1212 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1213 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1215 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_alive);
1216 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1217 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1218 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1220 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1223 server_init_dispatch_13(void)
1225 debug("server_init_dispatch_13");
1226 dispatch_init(NULL);
1227 dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1228 dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1229 dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1230 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1231 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1232 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1233 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1234 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1235 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1238 server_init_dispatch_15(void)
1240 server_init_dispatch_13();
1241 debug("server_init_dispatch_15");
1242 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1243 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1246 server_init_dispatch(void)
1249 server_init_dispatch_20();
1251 server_init_dispatch_13();
1253 server_init_dispatch_15();