2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * Server main loop for handling the interactive session.
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
13 * SSH2 support by Markus Friedl.
14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
19 * 1. Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution.
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 #include <sys/types.h>
59 #include "auth-options.h"
60 #include "serverloop.h"
64 extern ServerOptions options;
68 extern Authctxt *the_authctxt;
69 extern int use_privsep;
71 static Buffer stdin_buffer; /* Buffer for stdin data. */
72 static Buffer stdout_buffer; /* Buffer for stdout data. */
73 static Buffer stderr_buffer; /* Buffer for stderr data. */
74 static int fdin; /* Descriptor for stdin (for writing) */
75 static int fdout; /* Descriptor for stdout (for reading);
76 May be same number as fdin. */
77 static int fderr; /* Descriptor for stderr. May be -1. */
78 static long stdin_bytes = 0; /* Number of bytes written to stdin. */
79 static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
80 static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
81 static long fdout_bytes = 0; /* Number of stdout bytes read from program. */
82 static int stdin_eof = 0; /* EOF message received from client. */
83 static int fdout_eof = 0; /* EOF encountered reading from fdout. */
84 static int fderr_eof = 0; /* EOF encountered readung from fderr. */
85 static int fdin_is_tty = 0; /* fdin points to a tty. */
86 static int connection_in; /* Connection to client (input). */
87 static int connection_out; /* Connection to client (output). */
88 static int connection_closed = 0; /* Connection to client closed. */
89 static u_int buffer_high; /* "Soft" max buffer size. */
90 static int client_alive_timeouts = 0;
93 * This SIGCHLD kludge is used to detect when the child exits. The server
94 * will exit after that, as soon as forwarded connections have terminated.
97 static volatile sig_atomic_t child_terminated = 0; /* The child has terminated. */
99 /* Cleanup on signals (!use_privsep case only) */
100 static volatile sig_atomic_t received_sigterm = 0;
103 static void server_init_dispatch(void);
106 * we write to this pipe if a SIGCHLD is caught in order to avoid
107 * the race between select() and child_terminated
109 static int notify_pipe[2];
113 if (pipe(notify_pipe) < 0) {
114 error("pipe(notify_pipe) failed %s", strerror(errno));
115 } else if ((fcntl(notify_pipe[0], F_SETFD, 1) == -1) ||
116 (fcntl(notify_pipe[1], F_SETFD, 1) == -1)) {
117 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
118 close(notify_pipe[0]);
119 close(notify_pipe[1]);
121 set_nonblock(notify_pipe[0]);
122 set_nonblock(notify_pipe[1]);
125 notify_pipe[0] = -1; /* read end */
126 notify_pipe[1] = -1; /* write end */
131 if (notify_pipe[1] != -1)
132 write(notify_pipe[1], "", 1);
135 notify_prepare(fd_set *readset)
137 if (notify_pipe[0] != -1)
138 FD_SET(notify_pipe[0], readset);
141 notify_done(fd_set *readset)
145 if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
146 while (read(notify_pipe[0], &c, 1) != -1)
147 debug2("notify_done: reading");
151 sigchld_handler(int sig)
153 int save_errno = errno;
154 child_terminated = 1;
156 mysignal(SIGCHLD, sigchld_handler);
163 sigterm_handler(int sig)
165 received_sigterm = sig;
169 * Make packets from buffered stderr data, and buffer it for sending
173 make_packets_from_stderr_data(void)
177 /* Send buffered stderr data to the client. */
178 while (buffer_len(&stderr_buffer) > 0 &&
179 packet_not_very_much_data_to_write()) {
180 len = buffer_len(&stderr_buffer);
181 if (packet_is_interactive()) {
185 /* Keep the packets at reasonable size. */
186 if (len > packet_get_maxsize())
187 len = packet_get_maxsize();
189 packet_start(SSH_SMSG_STDERR_DATA);
190 packet_put_string(buffer_ptr(&stderr_buffer), len);
192 buffer_consume(&stderr_buffer, len);
198 * Make packets from buffered stdout data, and buffer it for sending to the
202 make_packets_from_stdout_data(void)
206 /* Send buffered stdout data to the client. */
207 while (buffer_len(&stdout_buffer) > 0 &&
208 packet_not_very_much_data_to_write()) {
209 len = buffer_len(&stdout_buffer);
210 if (packet_is_interactive()) {
214 /* Keep the packets at reasonable size. */
215 if (len > packet_get_maxsize())
216 len = packet_get_maxsize();
218 packet_start(SSH_SMSG_STDOUT_DATA);
219 packet_put_string(buffer_ptr(&stdout_buffer), len);
221 buffer_consume(&stdout_buffer, len);
227 client_alive_check(void)
231 /* timeout, check to see how many we have had */
232 if (++client_alive_timeouts > options.client_alive_count_max)
233 packet_disconnect("Timeout, your session not responding.");
236 * send a bogus global/channel request with "wantreply",
237 * we should get back a failure
239 if ((channel_id = channel_find_open()) == -1) {
240 packet_start(SSH2_MSG_GLOBAL_REQUEST);
241 packet_put_cstring("keepalive@openssh.com");
242 packet_put_char(1); /* boolean: want reply */
244 channel_request_start(channel_id, "keepalive@openssh.com", 1);
250 * Sleep in select() until we can do something. This will initialize the
251 * select masks. Upon return, the masks will indicate which descriptors
252 * have data or can accept data. Optionally, a maximum time can be specified
253 * for the duration of the wait (0 = infinite).
256 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
257 u_int *nallocp, u_int max_time_milliseconds)
259 struct timeval tv, *tvp;
261 int client_alive_scheduled = 0;
264 * if using client_alive, set the max timeout accordingly,
265 * and indicate that this particular timeout was for client
266 * alive by setting the client_alive_scheduled flag.
268 * this could be randomized somewhat to make traffic
269 * analysis more difficult, but we're not doing it yet.
272 max_time_milliseconds == 0 && options.client_alive_interval) {
273 client_alive_scheduled = 1;
274 max_time_milliseconds = options.client_alive_interval * 1000;
277 /* Allocate and update select() masks for channel descriptors. */
278 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0);
282 /* wrong: bad condition XXX */
283 if (channel_not_very_much_buffered_data())
285 FD_SET(connection_in, *readsetp);
288 * Read packets from the client unless we have too much
289 * buffered stdin or channel data.
291 if (buffer_len(&stdin_buffer) < buffer_high &&
292 channel_not_very_much_buffered_data())
293 FD_SET(connection_in, *readsetp);
295 * If there is not too much data already buffered going to
296 * the client, try to get some more data from the program.
298 if (packet_not_very_much_data_to_write()) {
300 FD_SET(fdout, *readsetp);
302 FD_SET(fderr, *readsetp);
305 * If we have buffered data, try to write some of that data
308 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
309 FD_SET(fdin, *writesetp);
311 notify_prepare(*readsetp);
314 * If we have buffered packet data going to the client, mark that
317 if (packet_have_data_to_write())
318 FD_SET(connection_out, *writesetp);
321 * If child has terminated and there is enough buffer space to read
322 * from it, then read as much as is available and exit.
324 if (child_terminated && packet_not_very_much_data_to_write())
325 if (max_time_milliseconds == 0 || client_alive_scheduled)
326 max_time_milliseconds = 100;
328 if (max_time_milliseconds == 0)
331 tv.tv_sec = max_time_milliseconds / 1000;
332 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
336 /* Wait for something to happen, or the timeout to expire. */
337 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
340 memset(*readsetp, 0, *nallocp);
341 memset(*writesetp, 0, *nallocp);
343 error("select: %.100s", strerror(errno));
344 } else if (ret == 0 && client_alive_scheduled)
345 client_alive_check();
347 notify_done(*readsetp);
351 * Processes input from the client and the program. Input data is stored
352 * in buffers and processed later.
355 process_input(fd_set * readset)
360 /* Read and buffer any input data from the client. */
361 if (FD_ISSET(connection_in, readset)) {
362 len = read(connection_in, buf, sizeof(buf));
364 verbose("Connection closed by %.100s",
365 get_remote_ipaddr());
366 connection_closed = 1;
370 } else if (len < 0) {
371 if (errno != EINTR && errno != EAGAIN) {
372 verbose("Read error from remote host "
374 get_remote_ipaddr(), strerror(errno));
378 /* Buffer any received data. */
379 packet_process_incoming(buf, len);
385 /* Read and buffer any available stdout data from the program. */
386 if (!fdout_eof && FD_ISSET(fdout, readset)) {
387 len = read(fdout, buf, sizeof(buf));
388 if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
390 } else if (len <= 0) {
393 buffer_append(&stdout_buffer, buf, len);
397 /* Read and buffer any available stderr data from the program. */
398 if (!fderr_eof && FD_ISSET(fderr, readset)) {
399 len = read(fderr, buf, sizeof(buf));
400 if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
402 } else if (len <= 0) {
405 buffer_append(&stderr_buffer, buf, len);
411 * Sends data from internal buffers to client program stdin.
414 process_output(fd_set * writeset)
421 /* Write buffered data to program stdin. */
422 if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
423 data = buffer_ptr(&stdin_buffer);
424 dlen = buffer_len(&stdin_buffer);
425 len = write(fdin, data, dlen);
426 if (len < 0 && (errno == EINTR || errno == EAGAIN)) {
428 } else if (len <= 0) {
432 shutdown(fdin, SHUT_WR); /* We will no longer send. */
435 /* Successful write. */
436 if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
437 tcgetattr(fdin, &tio) == 0 &&
438 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
440 * Simulate echo to reduce the impact of
443 packet_send_ignore(len);
446 /* Consume the data from the buffer. */
447 buffer_consume(&stdin_buffer, len);
448 /* Update the count of bytes written to the program. */
452 /* Send any buffered packet data to the client. */
453 if (FD_ISSET(connection_out, writeset))
458 * Wait until all buffered output has been sent to the client.
459 * This is used when the program terminates.
464 /* Send any buffered stdout data to the client. */
465 if (buffer_len(&stdout_buffer) > 0) {
466 packet_start(SSH_SMSG_STDOUT_DATA);
467 packet_put_string(buffer_ptr(&stdout_buffer),
468 buffer_len(&stdout_buffer));
470 /* Update the count of sent bytes. */
471 stdout_bytes += buffer_len(&stdout_buffer);
473 /* Send any buffered stderr data to the client. */
474 if (buffer_len(&stderr_buffer) > 0) {
475 packet_start(SSH_SMSG_STDERR_DATA);
476 packet_put_string(buffer_ptr(&stderr_buffer),
477 buffer_len(&stderr_buffer));
479 /* Update the count of sent bytes. */
480 stderr_bytes += buffer_len(&stderr_buffer);
482 /* Wait until all buffered data has been written to the client. */
487 process_buffered_input_packets(void)
489 dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
493 * Performs the interactive session. This handles data transmission between
494 * the client and the program. Note that the notion of stdin, stdout, and
495 * stderr in this function is sort of reversed: this function writes to
496 * stdin (of the child program), and reads from stdout and stderr (of the
500 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
502 fd_set *readset = NULL, *writeset = NULL;
505 int wait_status; /* Status returned by wait(). */
506 pid_t wait_pid; /* pid returned by wait(). */
507 int waiting_termination = 0; /* Have displayed waiting close message. */
508 u_int max_time_milliseconds;
509 u_int previous_stdout_buffer_bytes;
510 u_int stdout_buffer_bytes;
513 debug("Entering interactive session.");
515 /* Initialize the SIGCHLD kludge. */
516 child_terminated = 0;
517 mysignal(SIGCHLD, sigchld_handler);
520 signal(SIGTERM, sigterm_handler);
521 signal(SIGINT, sigterm_handler);
522 signal(SIGQUIT, sigterm_handler);
525 /* Initialize our global variables. */
533 /* we don't have stderr for interactive terminal sessions, see below */
537 if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
540 connection_in = packet_get_connection_in();
541 connection_out = packet_get_connection_out();
545 previous_stdout_buffer_bytes = 0;
547 /* Set approximate I/O buffer size. */
548 if (packet_is_interactive())
551 buffer_high = 64 * 1024;
554 /* Initialize max_fd to the maximum of the known file descriptors. */
555 max_fd = MAX(connection_in, connection_out);
556 max_fd = MAX(max_fd, fdin);
557 max_fd = MAX(max_fd, fdout);
559 max_fd = MAX(max_fd, fderr);
562 /* Initialize Initialize buffers. */
563 buffer_init(&stdin_buffer);
564 buffer_init(&stdout_buffer);
565 buffer_init(&stderr_buffer);
568 * If we have no separate fderr (which is the case when we have a pty
569 * - there we cannot make difference between data sent to stdout and
570 * stderr), indicate that we have seen an EOF from stderr. This way
571 * we don't need to check the descriptor everywhere.
576 server_init_dispatch();
578 /* Main loop of the server for the interactive session mode. */
581 /* Process buffered packets from the client. */
582 process_buffered_input_packets();
585 * If we have received eof, and there is no more pending
586 * input data, cause a real eof by closing fdin.
588 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
592 shutdown(fdin, SHUT_WR); /* We will no longer send. */
595 /* Make packets from buffered stderr data to send to the client. */
596 make_packets_from_stderr_data();
599 * Make packets from buffered stdout data to send to the
600 * client. If there is very little to send, this arranges to
601 * not send them now, but to wait a short while to see if we
602 * are getting more data. This is necessary, as some systems
603 * wake up readers from a pty after each separate character.
605 max_time_milliseconds = 0;
606 stdout_buffer_bytes = buffer_len(&stdout_buffer);
607 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
608 stdout_buffer_bytes != previous_stdout_buffer_bytes) {
609 /* try again after a while */
610 max_time_milliseconds = 10;
613 make_packets_from_stdout_data();
615 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
617 /* Send channel data to the client. */
618 if (packet_not_very_much_data_to_write())
619 channel_output_poll();
622 * Bail out of the loop if the program has closed its output
623 * descriptors, and we have no more data to send to the
624 * client, and there is no pending buffered data.
626 if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
627 buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
628 if (!channel_still_open())
630 if (!waiting_termination) {
631 const char *s = "Waiting for forwarded connections to terminate...\r\n";
633 waiting_termination = 1;
634 buffer_append(&stderr_buffer, s, strlen(s));
636 /* Display list of open channels. */
637 cp = channel_open_message();
638 buffer_append(&stderr_buffer, cp, strlen(cp));
642 max_fd = MAX(connection_in, connection_out);
643 max_fd = MAX(max_fd, fdin);
644 max_fd = MAX(max_fd, fdout);
645 max_fd = MAX(max_fd, fderr);
646 max_fd = MAX(max_fd, notify_pipe[0]);
648 /* Sleep in select() until we can do something. */
649 wait_until_can_do_something(&readset, &writeset, &max_fd,
650 &nalloc, max_time_milliseconds);
652 if (received_sigterm) {
653 logit("Exiting on signal %d", received_sigterm);
654 /* Clean up sessions, utmp, etc. */
658 /* Process any channel events. */
659 channel_after_select(readset, writeset);
661 /* Process input from the client and from program stdout/stderr. */
662 process_input(readset);
664 /* Process output to the client and to program stdin. */
665 process_output(writeset);
672 /* Cleanup and termination code. */
674 /* Wait until all output has been sent to the client. */
677 debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
678 stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
680 /* Free and clear the buffers. */
681 buffer_free(&stdin_buffer);
682 buffer_free(&stdout_buffer);
683 buffer_free(&stderr_buffer);
685 /* Close the file descriptors. */
700 /* We no longer want our SIGCHLD handler to be called. */
701 mysignal(SIGCHLD, SIG_DFL);
703 while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
705 packet_disconnect("wait: %.100s", strerror(errno));
707 error("Strange, wait returned pid %ld, expected %ld",
708 (long)wait_pid, (long)pid);
710 /* Check if it exited normally. */
711 if (WIFEXITED(wait_status)) {
712 /* Yes, normal exit. Get exit status and send it to the client. */
713 debug("Command exited with status %d.", WEXITSTATUS(wait_status));
714 packet_start(SSH_SMSG_EXITSTATUS);
715 packet_put_int(WEXITSTATUS(wait_status));
720 * Wait for exit confirmation. Note that there might be
721 * other packets coming before it; however, the program has
722 * already died so we just ignore them. The client is
723 * supposed to respond with the confirmation when it receives
727 type = packet_read();
729 while (type != SSH_CMSG_EXIT_CONFIRMATION);
731 debug("Received exit confirmation.");
734 /* Check if the program terminated due to a signal. */
735 if (WIFSIGNALED(wait_status))
736 packet_disconnect("Command terminated on signal %d.",
737 WTERMSIG(wait_status));
739 /* Some weird exit cause. Just exit. */
740 packet_disconnect("wait returned status %04x.", wait_status);
745 collect_children(void)
751 /* block SIGCHLD while we check for dead children */
753 sigaddset(&nset, SIGCHLD);
754 sigprocmask(SIG_BLOCK, &nset, &oset);
755 if (child_terminated) {
756 debug("Received SIGCHLD.");
757 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
758 (pid < 0 && errno == EINTR))
760 session_close_by_pid(pid, status);
761 child_terminated = 0;
763 sigprocmask(SIG_SETMASK, &oset, NULL);
767 server_loop2(Authctxt *authctxt)
769 fd_set *readset = NULL, *writeset = NULL;
770 int rekeying = 0, max_fd, nalloc = 0;
772 debug("Entering interactive session for SSH2.");
774 mysignal(SIGCHLD, sigchld_handler);
775 child_terminated = 0;
776 connection_in = packet_get_connection_in();
777 connection_out = packet_get_connection_out();
780 signal(SIGTERM, sigterm_handler);
781 signal(SIGINT, sigterm_handler);
782 signal(SIGQUIT, sigterm_handler);
787 max_fd = MAX(connection_in, connection_out);
788 max_fd = MAX(max_fd, notify_pipe[0]);
790 server_init_dispatch();
793 process_buffered_input_packets();
795 rekeying = (xxx_kex != NULL && !xxx_kex->done);
797 if (!rekeying && packet_not_very_much_data_to_write())
798 channel_output_poll();
799 wait_until_can_do_something(&readset, &writeset, &max_fd,
802 if (received_sigterm) {
803 logit("Exiting on signal %d", received_sigterm);
804 /* Clean up sessions, utmp, etc. */
810 channel_after_select(readset, writeset);
811 if (packet_need_rekeying()) {
812 debug("need rekeying");
814 kex_send_kexinit(xxx_kex);
817 process_input(readset);
818 if (connection_closed)
820 process_output(writeset);
829 /* free all channels, no more reads and writes */
832 /* free remaining sessions, e.g. remove wtmp entries */
833 session_destroy_all(NULL);
837 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
839 debug("Got %d/%u for keepalive", type, seq);
841 * reset timeout, since we got a sane answer from the client.
842 * even if this was generated by something other than
843 * the bogus CHANNEL_REQUEST we send for keepalives.
845 client_alive_timeouts = 0;
849 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
854 /* Stdin data from the client. Append it to the buffer. */
855 /* Ignore any data if the client has closed stdin. */
858 data = packet_get_string(&data_len);
860 buffer_append(&stdin_buffer, data, data_len);
861 memset(data, 0, data_len);
866 server_input_eof(int type, u_int32_t seq, void *ctxt)
869 * Eof from the client. The stdin descriptor to the
870 * program will be closed when all buffered data has
873 debug("EOF received for stdin.");
879 server_input_window_size(int type, u_int32_t seq, void *ctxt)
881 int row = packet_get_int();
882 int col = packet_get_int();
883 int xpixel = packet_get_int();
884 int ypixel = packet_get_int();
886 debug("Window change received.");
889 pty_change_window_size(fdin, row, col, xpixel, ypixel);
893 server_request_direct_tcpip(void)
897 char *target, *originator;
898 int target_port, originator_port;
900 target = packet_get_string(NULL);
901 target_port = packet_get_int();
902 originator = packet_get_string(NULL);
903 originator_port = packet_get_int();
906 debug("server_request_direct_tcpip: originator %s port %d, target %s port %d",
907 originator, originator_port, target, target_port);
909 /* XXX check permission */
910 sock = channel_connect_to(target, target_port);
915 c = channel_new("direct-tcpip", SSH_CHANNEL_CONNECTING,
916 sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT,
917 CHAN_TCP_PACKET_DEFAULT, 0, "direct-tcpip", 1);
922 server_request_tun(void)
928 mode = packet_get_int();
930 case SSH_TUNMODE_POINTOPOINT:
931 case SSH_TUNMODE_ETHERNET:
934 packet_send_debug("Unsupported tunnel device mode.");
937 if ((options.permit_tun & mode) == 0) {
938 packet_send_debug("Server has rejected tunnel device "
943 tun = packet_get_int();
944 if (forced_tun_device != -1) {
945 if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
947 tun = forced_tun_device;
949 sock = tun_open(tun, mode);
952 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
953 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
955 #if defined(SSH_TUN_FILTER)
956 if (mode == SSH_TUNMODE_POINTOPOINT)
957 channel_register_filter(c->self, sys_tun_infilter,
963 packet_send_debug("Failed to open the tunnel device.");
968 server_request_session(void)
972 debug("input_session_request");
975 * A server session has no fd to read or write until a
976 * CHANNEL_REQUEST for a shell is made, so we set the type to
977 * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all
978 * CHANNEL_REQUEST messages is registered.
980 c = channel_new("session", SSH_CHANNEL_LARVAL,
981 -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
982 0, "server-session", 1);
983 if (session_open(the_authctxt, c->self) != 1) {
984 debug("session open failed, free channel %d", c->self);
988 channel_register_cleanup(c->self, session_close_by_channel, 0);
993 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
998 u_int rmaxpack, rwindow, len;
1000 ctype = packet_get_string(&len);
1001 rchan = packet_get_int();
1002 rwindow = packet_get_int();
1003 rmaxpack = packet_get_int();
1005 debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1006 ctype, rchan, rwindow, rmaxpack);
1008 if (strcmp(ctype, "session") == 0) {
1009 c = server_request_session();
1010 } else if (strcmp(ctype, "direct-tcpip") == 0) {
1011 c = server_request_direct_tcpip();
1012 } else if (strcmp(ctype, "tun@openssh.com") == 0) {
1013 c = server_request_tun();
1016 debug("server_input_channel_open: confirm %s", ctype);
1017 c->remote_id = rchan;
1018 c->remote_window = rwindow;
1019 c->remote_maxpacket = rmaxpack;
1020 if (c->type != SSH_CHANNEL_CONNECTING) {
1021 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1022 packet_put_int(c->remote_id);
1023 packet_put_int(c->self);
1024 packet_put_int(c->local_window);
1025 packet_put_int(c->local_maxpacket);
1029 debug("server_input_channel_open: failure %s", ctype);
1030 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1031 packet_put_int(rchan);
1032 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1033 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1034 packet_put_cstring("open failed");
1035 packet_put_cstring("");
1043 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1049 rtype = packet_get_string(NULL);
1050 want_reply = packet_get_char();
1051 debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1053 /* -R style forwarding */
1054 if (strcmp(rtype, "tcpip-forward") == 0) {
1056 char *listen_address;
1057 u_short listen_port;
1059 pw = the_authctxt->pw;
1060 if (pw == NULL || !the_authctxt->valid)
1061 fatal("server_input_global_request: no/invalid user");
1062 listen_address = packet_get_string(NULL);
1063 listen_port = (u_short)packet_get_int();
1064 debug("server_input_global_request: tcpip-forward listen %s port %d",
1065 listen_address, listen_port);
1067 /* check permissions */
1068 if (!options.allow_tcp_forwarding ||
1069 no_port_forwarding_flag
1070 #ifndef NO_IPPORT_RESERVED_CONCEPT
1071 || (listen_port < IPPORT_RESERVED && pw->pw_uid != 0)
1075 packet_send_debug("Server has disabled port forwarding.");
1077 /* Start listening on the port */
1078 success = channel_setup_remote_fwd_listener(
1079 listen_address, listen_port, options.gateway_ports);
1081 xfree(listen_address);
1082 } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1083 char *cancel_address;
1084 u_short cancel_port;
1086 cancel_address = packet_get_string(NULL);
1087 cancel_port = (u_short)packet_get_int();
1088 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1089 cancel_address, cancel_port);
1091 success = channel_cancel_rport_listener(cancel_address,
1095 packet_start(success ?
1096 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1098 packet_write_wait();
1103 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1106 int id, reply, success = 0;
1109 id = packet_get_int();
1110 rtype = packet_get_string(NULL);
1111 reply = packet_get_char();
1113 debug("server_input_channel_req: channel %d request %s reply %d",
1116 if ((c = channel_lookup(id)) == NULL)
1117 packet_disconnect("server_input_channel_req: "
1118 "unknown channel %d", id);
1119 if (c->type == SSH_CHANNEL_LARVAL || c->type == SSH_CHANNEL_OPEN)
1120 success = session_input_channel_req(c, rtype);
1122 packet_start(success ?
1123 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1124 packet_put_int(c->remote_id);
1131 server_init_dispatch_20(void)
1133 debug("server_init_dispatch_20");
1134 dispatch_init(&dispatch_protocol_error);
1135 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1136 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1137 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1138 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1139 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1140 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1141 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1142 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1143 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1144 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1146 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1147 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1148 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1150 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1153 server_init_dispatch_13(void)
1155 debug("server_init_dispatch_13");
1156 dispatch_init(NULL);
1157 dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1158 dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1159 dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1160 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1161 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1162 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1163 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1164 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1165 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1168 server_init_dispatch_15(void)
1170 server_init_dispatch_13();
1171 debug("server_init_dispatch_15");
1172 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1173 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1176 server_init_dispatch(void)
1179 server_init_dispatch_20();
1181 server_init_dispatch_13();
1183 server_init_dispatch_15();