1 /* $OpenBSD: serverloop.c,v 1.170 2014/02/02 03:44:31 djm 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.
42 #include <sys/types.h>
43 #include <sys/param.h>
45 #include <sys/socket.h>
46 #ifdef HAVE_SYS_TIME_H
47 # include <sys/time.h>
50 #include <netinet/in.h>
61 #include "openbsd-compat/sys-queue.h"
80 #include "auth-options.h"
81 #include "serverloop.h"
85 extern ServerOptions options;
89 extern Authctxt *the_authctxt;
90 extern int use_privsep;
92 static Buffer stdin_buffer; /* Buffer for stdin data. */
93 static Buffer stdout_buffer; /* Buffer for stdout data. */
94 static Buffer stderr_buffer; /* Buffer for stderr data. */
95 static int fdin; /* Descriptor for stdin (for writing) */
96 static int fdout; /* Descriptor for stdout (for reading);
97 May be same number as fdin. */
98 static int fderr; /* Descriptor for stderr. May be -1. */
99 static long stdin_bytes = 0; /* Number of bytes written to stdin. */
100 static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
101 static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
102 static long fdout_bytes = 0; /* Number of stdout bytes read from program. */
103 static int stdin_eof = 0; /* EOF message received from client. */
104 static int fdout_eof = 0; /* EOF encountered reading from fdout. */
105 static int fderr_eof = 0; /* EOF encountered readung from fderr. */
106 static int fdin_is_tty = 0; /* fdin points to a tty. */
107 static int connection_in; /* Connection to client (input). */
108 static int connection_out; /* Connection to client (output). */
109 static int connection_closed = 0; /* Connection to client closed. */
110 static u_int buffer_high; /* "Soft" max buffer size. */
111 static int no_more_sessions = 0; /* Disallow further sessions. */
114 * This SIGCHLD kludge is used to detect when the child exits. The server
115 * will exit after that, as soon as forwarded connections have terminated.
118 static volatile sig_atomic_t child_terminated = 0; /* The child has terminated. */
120 /* Cleanup on signals (!use_privsep case only) */
121 static volatile sig_atomic_t received_sigterm = 0;
124 static void server_init_dispatch(void);
127 * we write to this pipe if a SIGCHLD is caught in order to avoid
128 * the race between select() and child_terminated
130 static int notify_pipe[2];
134 if (pipe(notify_pipe) < 0) {
135 error("pipe(notify_pipe) failed %s", strerror(errno));
136 } else if ((fcntl(notify_pipe[0], F_SETFD, FD_CLOEXEC) == -1) ||
137 (fcntl(notify_pipe[1], F_SETFD, FD_CLOEXEC) == -1)) {
138 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
139 close(notify_pipe[0]);
140 close(notify_pipe[1]);
142 set_nonblock(notify_pipe[0]);
143 set_nonblock(notify_pipe[1]);
146 notify_pipe[0] = -1; /* read end */
147 notify_pipe[1] = -1; /* write end */
152 if (notify_pipe[1] != -1)
153 (void)write(notify_pipe[1], "", 1);
156 notify_prepare(fd_set *readset)
158 if (notify_pipe[0] != -1)
159 FD_SET(notify_pipe[0], readset);
162 notify_done(fd_set *readset)
166 if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
167 while (read(notify_pipe[0], &c, 1) != -1)
168 debug2("notify_done: reading");
173 sigchld_handler(int sig)
175 int save_errno = errno;
176 child_terminated = 1;
178 mysignal(SIGCHLD, sigchld_handler);
186 sigterm_handler(int sig)
188 received_sigterm = sig;
192 * Make packets from buffered stderr data, and buffer it for sending
196 make_packets_from_stderr_data(void)
200 /* Send buffered stderr data to the client. */
201 while (buffer_len(&stderr_buffer) > 0 &&
202 packet_not_very_much_data_to_write()) {
203 len = buffer_len(&stderr_buffer);
204 if (packet_is_interactive()) {
208 /* Keep the packets at reasonable size. */
209 if (len > packet_get_maxsize())
210 len = packet_get_maxsize();
212 packet_start(SSH_SMSG_STDERR_DATA);
213 packet_put_string(buffer_ptr(&stderr_buffer), len);
215 buffer_consume(&stderr_buffer, len);
221 * Make packets from buffered stdout data, and buffer it for sending to the
225 make_packets_from_stdout_data(void)
229 /* Send buffered stdout data to the client. */
230 while (buffer_len(&stdout_buffer) > 0 &&
231 packet_not_very_much_data_to_write()) {
232 len = buffer_len(&stdout_buffer);
233 if (packet_is_interactive()) {
237 /* Keep the packets at reasonable size. */
238 if (len > packet_get_maxsize())
239 len = packet_get_maxsize();
241 packet_start(SSH_SMSG_STDOUT_DATA);
242 packet_put_string(buffer_ptr(&stdout_buffer), len);
244 buffer_consume(&stdout_buffer, len);
250 client_alive_check(void)
254 /* timeout, check to see how many we have had */
255 if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
256 logit("Timeout, client not responding.");
261 * send a bogus global/channel request with "wantreply",
262 * we should get back a failure
264 if ((channel_id = channel_find_open()) == -1) {
265 packet_start(SSH2_MSG_GLOBAL_REQUEST);
266 packet_put_cstring("keepalive@openssh.com");
267 packet_put_char(1); /* boolean: want reply */
269 channel_request_start(channel_id, "keepalive@openssh.com", 1);
275 * Sleep in select() until we can do something. This will initialize the
276 * select masks. Upon return, the masks will indicate which descriptors
277 * have data or can accept data. Optionally, a maximum time can be specified
278 * for the duration of the wait (0 = infinite).
281 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
282 u_int *nallocp, u_int64_t max_time_milliseconds)
284 struct timeval tv, *tvp;
286 time_t minwait_secs = 0;
287 int client_alive_scheduled = 0;
288 int program_alive_scheduled = 0;
290 /* Allocate and update select() masks for channel descriptors. */
291 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp,
294 if (minwait_secs != 0)
295 max_time_milliseconds = MIN(max_time_milliseconds,
296 (u_int)minwait_secs * 1000);
299 * if using client_alive, set the max timeout accordingly,
300 * and indicate that this particular timeout was for client
301 * alive by setting the client_alive_scheduled flag.
303 * this could be randomized somewhat to make traffic
304 * analysis more difficult, but we're not doing it yet.
307 max_time_milliseconds == 0 && options.client_alive_interval) {
308 client_alive_scheduled = 1;
309 max_time_milliseconds =
310 (u_int64_t)options.client_alive_interval * 1000;
315 /* wrong: bad condition XXX */
316 if (channel_not_very_much_buffered_data())
318 FD_SET(connection_in, *readsetp);
321 * Read packets from the client unless we have too much
322 * buffered stdin or channel data.
324 if (buffer_len(&stdin_buffer) < buffer_high &&
325 channel_not_very_much_buffered_data())
326 FD_SET(connection_in, *readsetp);
328 * If there is not too much data already buffered going to
329 * the client, try to get some more data from the program.
331 if (packet_not_very_much_data_to_write()) {
332 program_alive_scheduled = child_terminated;
334 FD_SET(fdout, *readsetp);
336 FD_SET(fderr, *readsetp);
339 * If we have buffered data, try to write some of that data
342 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
343 FD_SET(fdin, *writesetp);
345 notify_prepare(*readsetp);
348 * If we have buffered packet data going to the client, mark that
351 if (packet_have_data_to_write())
352 FD_SET(connection_out, *writesetp);
355 * If child has terminated and there is enough buffer space to read
356 * from it, then read as much as is available and exit.
358 if (child_terminated && packet_not_very_much_data_to_write())
359 if (max_time_milliseconds == 0 || client_alive_scheduled)
360 max_time_milliseconds = 100;
362 if (max_time_milliseconds == 0)
365 tv.tv_sec = max_time_milliseconds / 1000;
366 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
370 /* Wait for something to happen, or the timeout to expire. */
371 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
374 memset(*readsetp, 0, *nallocp);
375 memset(*writesetp, 0, *nallocp);
377 error("select: %.100s", strerror(errno));
379 if (ret == 0 && client_alive_scheduled)
380 client_alive_check();
381 if (!compat20 && program_alive_scheduled && fdin_is_tty) {
383 FD_SET(fdout, *readsetp);
385 FD_SET(fderr, *readsetp);
389 notify_done(*readsetp);
393 * Processes input from the client and the program. Input data is stored
394 * in buffers and processed later.
397 process_input(fd_set *readset)
402 /* Read and buffer any input data from the client. */
403 if (FD_ISSET(connection_in, readset)) {
405 len = roaming_read(connection_in, buf, sizeof(buf), &cont);
409 verbose("Connection closed by %.100s",
410 get_remote_ipaddr());
411 connection_closed = 1;
415 } else if (len < 0) {
416 if (errno != EINTR && errno != EAGAIN &&
417 errno != EWOULDBLOCK) {
418 verbose("Read error from remote host "
420 get_remote_ipaddr(), strerror(errno));
424 /* Buffer any received data. */
425 packet_process_incoming(buf, len);
431 /* Read and buffer any available stdout data from the program. */
432 if (!fdout_eof && FD_ISSET(fdout, readset)) {
434 len = read(fdout, buf, sizeof(buf));
435 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
436 errno == EWOULDBLOCK) && !child_terminated))) {
439 } else if (len <= 0) {
441 } else if ((!isatty(fdout) && len <= 0) ||
442 (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
446 buffer_append(&stdout_buffer, buf, len);
450 /* Read and buffer any available stderr data from the program. */
451 if (!fderr_eof && FD_ISSET(fderr, readset)) {
453 len = read(fderr, buf, sizeof(buf));
454 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
455 errno == EWOULDBLOCK) && !child_terminated))) {
458 } else if (len <= 0) {
460 } else if ((!isatty(fderr) && len <= 0) ||
461 (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
465 buffer_append(&stderr_buffer, buf, len);
471 * Sends data from internal buffers to client program stdin.
474 process_output(fd_set *writeset)
481 /* Write buffered data to program stdin. */
482 if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
483 data = buffer_ptr(&stdin_buffer);
484 dlen = buffer_len(&stdin_buffer);
485 len = write(fdin, data, dlen);
487 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) {
489 } else if (len <= 0) {
493 shutdown(fdin, SHUT_WR); /* We will no longer send. */
496 /* Successful write. */
497 if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
498 tcgetattr(fdin, &tio) == 0 &&
499 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
501 * Simulate echo to reduce the impact of
504 packet_send_ignore(len);
507 /* Consume the data from the buffer. */
508 buffer_consume(&stdin_buffer, len);
509 /* Update the count of bytes written to the program. */
513 /* Send any buffered packet data to the client. */
514 if (FD_ISSET(connection_out, writeset))
519 * Wait until all buffered output has been sent to the client.
520 * This is used when the program terminates.
525 /* Send any buffered stdout data to the client. */
526 if (buffer_len(&stdout_buffer) > 0) {
527 packet_start(SSH_SMSG_STDOUT_DATA);
528 packet_put_string(buffer_ptr(&stdout_buffer),
529 buffer_len(&stdout_buffer));
531 /* Update the count of sent bytes. */
532 stdout_bytes += buffer_len(&stdout_buffer);
534 /* Send any buffered stderr data to the client. */
535 if (buffer_len(&stderr_buffer) > 0) {
536 packet_start(SSH_SMSG_STDERR_DATA);
537 packet_put_string(buffer_ptr(&stderr_buffer),
538 buffer_len(&stderr_buffer));
540 /* Update the count of sent bytes. */
541 stderr_bytes += buffer_len(&stderr_buffer);
543 /* Wait until all buffered data has been written to the client. */
548 process_buffered_input_packets(void)
550 dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
554 * Performs the interactive session. This handles data transmission between
555 * the client and the program. Note that the notion of stdin, stdout, and
556 * stderr in this function is sort of reversed: this function writes to
557 * stdin (of the child program), and reads from stdout and stderr (of the
561 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
563 fd_set *readset = NULL, *writeset = NULL;
566 int wait_status; /* Status returned by wait(). */
567 pid_t wait_pid; /* pid returned by wait(). */
568 int waiting_termination = 0; /* Have displayed waiting close message. */
569 u_int64_t max_time_milliseconds;
570 u_int previous_stdout_buffer_bytes;
571 u_int stdout_buffer_bytes;
574 debug("Entering interactive session.");
576 /* Initialize the SIGCHLD kludge. */
577 child_terminated = 0;
578 mysignal(SIGCHLD, sigchld_handler);
581 signal(SIGTERM, sigterm_handler);
582 signal(SIGINT, sigterm_handler);
583 signal(SIGQUIT, sigterm_handler);
586 /* Initialize our global variables. */
594 /* we don't have stderr for interactive terminal sessions, see below */
598 if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
601 connection_in = packet_get_connection_in();
602 connection_out = packet_get_connection_out();
606 previous_stdout_buffer_bytes = 0;
608 /* Set approximate I/O buffer size. */
609 if (packet_is_interactive())
612 buffer_high = 64 * 1024;
615 /* Initialize max_fd to the maximum of the known file descriptors. */
616 max_fd = MAX(connection_in, connection_out);
617 max_fd = MAX(max_fd, fdin);
618 max_fd = MAX(max_fd, fdout);
620 max_fd = MAX(max_fd, fderr);
623 /* Initialize Initialize buffers. */
624 buffer_init(&stdin_buffer);
625 buffer_init(&stdout_buffer);
626 buffer_init(&stderr_buffer);
629 * If we have no separate fderr (which is the case when we have a pty
630 * - there we cannot make difference between data sent to stdout and
631 * stderr), indicate that we have seen an EOF from stderr. This way
632 * we don't need to check the descriptor everywhere.
637 server_init_dispatch();
639 /* Main loop of the server for the interactive session mode. */
642 /* Process buffered packets from the client. */
643 process_buffered_input_packets();
646 * If we have received eof, and there is no more pending
647 * input data, cause a real eof by closing fdin.
649 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
653 shutdown(fdin, SHUT_WR); /* We will no longer send. */
656 /* Make packets from buffered stderr data to send to the client. */
657 make_packets_from_stderr_data();
660 * Make packets from buffered stdout data to send to the
661 * client. If there is very little to send, this arranges to
662 * not send them now, but to wait a short while to see if we
663 * are getting more data. This is necessary, as some systems
664 * wake up readers from a pty after each separate character.
666 max_time_milliseconds = 0;
667 stdout_buffer_bytes = buffer_len(&stdout_buffer);
668 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
669 stdout_buffer_bytes != previous_stdout_buffer_bytes) {
670 /* try again after a while */
671 max_time_milliseconds = 10;
674 make_packets_from_stdout_data();
676 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
678 /* Send channel data to the client. */
679 if (packet_not_very_much_data_to_write())
680 channel_output_poll();
683 * Bail out of the loop if the program has closed its output
684 * descriptors, and we have no more data to send to the
685 * client, and there is no pending buffered data.
687 if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
688 buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
689 if (!channel_still_open())
691 if (!waiting_termination) {
692 const char *s = "Waiting for forwarded connections to terminate...\r\n";
694 waiting_termination = 1;
695 buffer_append(&stderr_buffer, s, strlen(s));
697 /* Display list of open channels. */
698 cp = channel_open_message();
699 buffer_append(&stderr_buffer, cp, strlen(cp));
703 max_fd = MAX(connection_in, connection_out);
704 max_fd = MAX(max_fd, fdin);
705 max_fd = MAX(max_fd, fdout);
706 max_fd = MAX(max_fd, fderr);
707 max_fd = MAX(max_fd, notify_pipe[0]);
709 /* Sleep in select() until we can do something. */
710 wait_until_can_do_something(&readset, &writeset, &max_fd,
711 &nalloc, max_time_milliseconds);
713 if (received_sigterm) {
714 logit("Exiting on signal %d", (int)received_sigterm);
715 /* Clean up sessions, utmp, etc. */
719 /* Process any channel events. */
720 channel_after_select(readset, writeset);
722 /* Process input from the client and from program stdout/stderr. */
723 process_input(readset);
725 /* Process output to the client and to program stdin. */
726 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;
831 u_int64_t rekey_timeout_ms = 0;
833 debug("Entering interactive session for SSH2.");
835 mysignal(SIGCHLD, sigchld_handler);
836 child_terminated = 0;
837 connection_in = packet_get_connection_in();
838 connection_out = packet_get_connection_out();
841 signal(SIGTERM, sigterm_handler);
842 signal(SIGINT, sigterm_handler);
843 signal(SIGQUIT, sigterm_handler);
848 max_fd = MAX(connection_in, connection_out);
849 max_fd = MAX(max_fd, notify_pipe[0]);
851 server_init_dispatch();
854 process_buffered_input_packets();
856 rekeying = (xxx_kex != NULL && !xxx_kex->done);
858 if (!rekeying && packet_not_very_much_data_to_write())
859 channel_output_poll();
860 if (options.rekey_interval > 0 && compat20 && !rekeying)
861 rekey_timeout_ms = packet_get_rekey_timeout() * 1000;
863 rekey_timeout_ms = 0;
865 wait_until_can_do_something(&readset, &writeset, &max_fd,
866 &nalloc, rekey_timeout_ms);
868 if (received_sigterm) {
869 logit("Exiting on signal %d", (int)received_sigterm);
870 /* Clean up sessions, utmp, etc. */
876 channel_after_select(readset, writeset);
877 if (packet_need_rekeying()) {
878 debug("need rekeying");
880 kex_send_kexinit(xxx_kex);
883 process_input(readset);
884 if (connection_closed)
886 process_output(writeset);
893 /* free all channels, no more reads and writes */
896 /* free remaining sessions, e.g. remove wtmp entries */
897 session_destroy_all(NULL);
901 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
903 debug("Got %d/%u for keepalive", type, seq);
905 * reset timeout, since we got a sane answer from the client.
906 * even if this was generated by something other than
907 * the bogus CHANNEL_REQUEST we send for keepalives.
909 packet_set_alive_timeouts(0);
913 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
918 /* Stdin data from the client. Append it to the buffer. */
919 /* Ignore any data if the client has closed stdin. */
922 data = packet_get_string(&data_len);
924 buffer_append(&stdin_buffer, data, data_len);
925 explicit_bzero(data, data_len);
930 server_input_eof(int type, u_int32_t seq, void *ctxt)
933 * Eof from the client. The stdin descriptor to the
934 * program will be closed when all buffered data has
937 debug("EOF received for stdin.");
943 server_input_window_size(int type, u_int32_t seq, void *ctxt)
945 u_int row = packet_get_int();
946 u_int col = packet_get_int();
947 u_int xpixel = packet_get_int();
948 u_int ypixel = packet_get_int();
950 debug("Window change received.");
953 pty_change_window_size(fdin, row, col, xpixel, ypixel);
957 server_request_direct_tcpip(void)
960 char *target, *originator;
961 u_short target_port, originator_port;
963 target = packet_get_string(NULL);
964 target_port = packet_get_int();
965 originator = packet_get_string(NULL);
966 originator_port = packet_get_int();
969 debug("server_request_direct_tcpip: originator %s port %d, target %s "
970 "port %d", originator, originator_port, target, target_port);
972 /* XXX fine grained permissions */
973 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
974 !no_port_forwarding_flag) {
975 c = channel_connect_to(target, target_port,
976 "direct-tcpip", "direct-tcpip");
978 logit("refused local port forward: "
979 "originator %s port %d, target %s port %d",
980 originator, originator_port, target, target_port);
990 server_request_tun(void)
996 mode = packet_get_int();
998 case SSH_TUNMODE_POINTOPOINT:
999 case SSH_TUNMODE_ETHERNET:
1002 packet_send_debug("Unsupported tunnel device mode.");
1005 if ((options.permit_tun & mode) == 0) {
1006 packet_send_debug("Server has rejected tunnel device "
1011 tun = packet_get_int();
1012 if (forced_tun_device != -1) {
1013 if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1015 tun = forced_tun_device;
1017 sock = tun_open(tun, mode);
1020 if (options.hpn_disabled)
1021 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1022 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
1025 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1026 options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0,
1029 #if defined(SSH_TUN_FILTER)
1030 if (mode == SSH_TUNMODE_POINTOPOINT)
1031 channel_register_filter(c->self, sys_tun_infilter,
1032 sys_tun_outfilter, NULL, NULL);
1037 packet_send_debug("Failed to open the tunnel device.");
1042 server_request_session(void)
1046 debug("input_session_request");
1049 if (no_more_sessions) {
1050 packet_disconnect("Possible attack: attempt to open a session "
1051 "after additional sessions disabled");
1055 * A server session has no fd to read or write until a
1056 * CHANNEL_REQUEST for a shell is made, so we set the type to
1057 * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all
1058 * CHANNEL_REQUEST messages is registered.
1060 c = channel_new("session", SSH_CHANNEL_LARVAL,
1061 -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1062 0, "server-session", 1);
1063 if (!options.hpn_disabled && options.tcp_rcv_buf_poll)
1064 c->dynamic_window = 1;
1065 if (session_open(the_authctxt, c->self) != 1) {
1066 debug("session open failed, free channel %d", c->self);
1070 channel_register_cleanup(c->self, session_close_by_channel, 0);
1075 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1080 u_int rmaxpack, rwindow, len;
1082 ctype = packet_get_string(&len);
1083 rchan = packet_get_int();
1084 rwindow = packet_get_int();
1085 rmaxpack = packet_get_int();
1087 debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1088 ctype, rchan, rwindow, rmaxpack);
1090 if (strcmp(ctype, "session") == 0) {
1091 c = server_request_session();
1092 } else if (strcmp(ctype, "direct-tcpip") == 0) {
1093 c = server_request_direct_tcpip();
1094 } else if (strcmp(ctype, "tun@openssh.com") == 0) {
1095 c = server_request_tun();
1098 debug("server_input_channel_open: confirm %s", ctype);
1099 c->remote_id = rchan;
1100 c->remote_window = rwindow;
1101 c->remote_maxpacket = rmaxpack;
1102 if (c->type != SSH_CHANNEL_CONNECTING) {
1103 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1104 packet_put_int(c->remote_id);
1105 packet_put_int(c->self);
1106 packet_put_int(c->local_window);
1107 packet_put_int(c->local_maxpacket);
1111 debug("server_input_channel_open: failure %s", ctype);
1112 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1113 packet_put_int(rchan);
1114 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1115 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1116 packet_put_cstring("open failed");
1117 packet_put_cstring("");
1125 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1129 int success = 0, allocated_listen_port = 0;
1131 rtype = packet_get_string(NULL);
1132 want_reply = packet_get_char();
1133 debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1135 /* -R style forwarding */
1136 if (strcmp(rtype, "tcpip-forward") == 0) {
1138 char *listen_address;
1139 u_short listen_port;
1141 pw = the_authctxt->pw;
1142 if (pw == NULL || !the_authctxt->valid)
1143 fatal("server_input_global_request: no/invalid user");
1144 listen_address = packet_get_string(NULL);
1145 listen_port = (u_short)packet_get_int();
1146 debug("server_input_global_request: tcpip-forward listen %s port %d",
1147 listen_address, listen_port);
1149 /* check permissions */
1150 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
1151 no_port_forwarding_flag ||
1152 (!want_reply && listen_port == 0)
1153 #ifndef NO_IPPORT_RESERVED_CONCEPT
1154 || (listen_port != 0 && listen_port < IPPORT_RESERVED &&
1159 packet_send_debug("Server has disabled port forwarding.");
1161 /* Start listening on the port */
1162 success = channel_setup_remote_fwd_listener(
1163 listen_address, listen_port,
1164 &allocated_listen_port, options.gateway_ports);
1166 free(listen_address);
1167 } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1168 char *cancel_address;
1169 u_short cancel_port;
1171 cancel_address = packet_get_string(NULL);
1172 cancel_port = (u_short)packet_get_int();
1173 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1174 cancel_address, cancel_port);
1176 success = channel_cancel_rport_listener(cancel_address,
1178 free(cancel_address);
1179 } else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
1180 no_more_sessions = 1;
1184 packet_start(success ?
1185 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1186 if (success && allocated_listen_port > 0)
1187 packet_put_int(allocated_listen_port);
1189 packet_write_wait();
1195 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1198 int id, reply, success = 0;
1201 id = packet_get_int();
1202 rtype = packet_get_string(NULL);
1203 reply = packet_get_char();
1205 debug("server_input_channel_req: channel %d request %s reply %d",
1208 if ((c = channel_lookup(id)) == NULL)
1209 packet_disconnect("server_input_channel_req: "
1210 "unknown channel %d", id);
1211 if (!strcmp(rtype, "eow@openssh.com")) {
1214 } else if ((c->type == SSH_CHANNEL_LARVAL ||
1215 c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
1216 success = session_input_channel_req(c, rtype);
1218 packet_start(success ?
1219 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1220 packet_put_int(c->remote_id);
1227 server_init_dispatch_20(void)
1229 debug("server_init_dispatch_20");
1230 dispatch_init(&dispatch_protocol_error);
1231 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1232 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1233 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1234 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1235 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1236 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1237 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1238 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1239 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1240 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1242 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_alive);
1243 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1244 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1245 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1247 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1250 server_init_dispatch_13(void)
1252 debug("server_init_dispatch_13");
1253 dispatch_init(NULL);
1254 dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1255 dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1256 dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1257 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1258 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1259 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1260 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1261 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1262 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1265 server_init_dispatch_15(void)
1267 server_init_dispatch_13();
1268 debug("server_init_dispatch_15");
1269 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1270 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1273 server_init_dispatch(void)
1276 server_init_dispatch_20();
1278 server_init_dispatch_13();
1280 server_init_dispatch_15();