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.
41 #include <sys/types.h>
42 #include <sys/param.h>
44 #include <sys/socket.h>
45 #ifdef HAVE_SYS_TIME_H
46 # include <sys/time.h>
49 #include <netinet/in.h>
60 #include "openbsd-compat/sys-queue.h"
79 #include "auth-options.h"
80 #include "serverloop.h"
84 extern ServerOptions options;
88 extern Authctxt *the_authctxt;
89 extern int use_privsep;
91 static Buffer stdin_buffer; /* Buffer for stdin data. */
92 static Buffer stdout_buffer; /* Buffer for stdout data. */
93 static Buffer stderr_buffer; /* Buffer for stderr data. */
94 static int fdin; /* Descriptor for stdin (for writing) */
95 static int fdout; /* Descriptor for stdout (for reading);
96 May be same number as fdin. */
97 static int fderr; /* Descriptor for stderr. May be -1. */
98 static long stdin_bytes = 0; /* Number of bytes written to stdin. */
99 static long stdout_bytes = 0; /* Number of stdout bytes sent to client. */
100 static long stderr_bytes = 0; /* Number of stderr bytes sent to client. */
101 static long fdout_bytes = 0; /* Number of stdout bytes read from program. */
102 static int stdin_eof = 0; /* EOF message received from client. */
103 static int fdout_eof = 0; /* EOF encountered reading from fdout. */
104 static int fderr_eof = 0; /* EOF encountered readung from fderr. */
105 static int fdin_is_tty = 0; /* fdin points to a tty. */
106 static int connection_in; /* Connection to client (input). */
107 static int connection_out; /* Connection to client (output). */
108 static int connection_closed = 0; /* Connection to client closed. */
109 static u_int buffer_high; /* "Soft" max buffer size. */
110 static int no_more_sessions = 0; /* Disallow further sessions. */
113 * This SIGCHLD kludge is used to detect when the child exits. The server
114 * will exit after that, as soon as forwarded connections have terminated.
117 static volatile sig_atomic_t child_terminated = 0; /* The child has terminated. */
119 /* Cleanup on signals (!use_privsep case only) */
120 static volatile sig_atomic_t received_sigterm = 0;
123 static void server_init_dispatch(void);
126 * we write to this pipe if a SIGCHLD is caught in order to avoid
127 * the race between select() and child_terminated
129 static int notify_pipe[2];
133 if (pipe(notify_pipe) < 0) {
134 error("pipe(notify_pipe) failed %s", strerror(errno));
135 } else if ((fcntl(notify_pipe[0], F_SETFD, FD_CLOEXEC) == -1) ||
136 (fcntl(notify_pipe[1], F_SETFD, FD_CLOEXEC) == -1)) {
137 error("fcntl(notify_pipe, F_SETFD) failed %s", strerror(errno));
138 close(notify_pipe[0]);
139 close(notify_pipe[1]);
141 set_nonblock(notify_pipe[0]);
142 set_nonblock(notify_pipe[1]);
145 notify_pipe[0] = -1; /* read end */
146 notify_pipe[1] = -1; /* write end */
151 if (notify_pipe[1] != -1)
152 (void)write(notify_pipe[1], "", 1);
155 notify_prepare(fd_set *readset)
157 if (notify_pipe[0] != -1)
158 FD_SET(notify_pipe[0], readset);
161 notify_done(fd_set *readset)
165 if (notify_pipe[0] != -1 && FD_ISSET(notify_pipe[0], readset))
166 while (read(notify_pipe[0], &c, 1) != -1)
167 debug2("notify_done: reading");
172 sigchld_handler(int sig)
174 int save_errno = errno;
175 child_terminated = 1;
177 mysignal(SIGCHLD, sigchld_handler);
185 sigterm_handler(int sig)
187 received_sigterm = sig;
191 * Make packets from buffered stderr data, and buffer it for sending
195 make_packets_from_stderr_data(void)
199 /* Send buffered stderr data to the client. */
200 while (buffer_len(&stderr_buffer) > 0 &&
201 packet_not_very_much_data_to_write()) {
202 len = buffer_len(&stderr_buffer);
203 if (packet_is_interactive()) {
207 /* Keep the packets at reasonable size. */
208 if (len > packet_get_maxsize())
209 len = packet_get_maxsize();
211 packet_start(SSH_SMSG_STDERR_DATA);
212 packet_put_string(buffer_ptr(&stderr_buffer), len);
214 buffer_consume(&stderr_buffer, len);
220 * Make packets from buffered stdout data, and buffer it for sending to the
224 make_packets_from_stdout_data(void)
228 /* Send buffered stdout data to the client. */
229 while (buffer_len(&stdout_buffer) > 0 &&
230 packet_not_very_much_data_to_write()) {
231 len = buffer_len(&stdout_buffer);
232 if (packet_is_interactive()) {
236 /* Keep the packets at reasonable size. */
237 if (len > packet_get_maxsize())
238 len = packet_get_maxsize();
240 packet_start(SSH_SMSG_STDOUT_DATA);
241 packet_put_string(buffer_ptr(&stdout_buffer), len);
243 buffer_consume(&stdout_buffer, len);
249 client_alive_check(void)
253 /* timeout, check to see how many we have had */
254 if (packet_inc_alive_timeouts() > options.client_alive_count_max) {
255 logit("Timeout, client not responding.");
260 * send a bogus global/channel request with "wantreply",
261 * we should get back a failure
263 if ((channel_id = channel_find_open()) == -1) {
264 packet_start(SSH2_MSG_GLOBAL_REQUEST);
265 packet_put_cstring("keepalive@openssh.com");
266 packet_put_char(1); /* boolean: want reply */
268 channel_request_start(channel_id, "keepalive@openssh.com", 1);
274 * Sleep in select() until we can do something. This will initialize the
275 * select masks. Upon return, the masks will indicate which descriptors
276 * have data or can accept data. Optionally, a maximum time can be specified
277 * for the duration of the wait (0 = infinite).
280 wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
281 u_int *nallocp, u_int64_t max_time_milliseconds)
283 struct timeval tv, *tvp;
285 time_t minwait_secs = 0;
286 int client_alive_scheduled = 0;
287 int program_alive_scheduled = 0;
289 /* Allocate and update select() masks for channel descriptors. */
290 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp,
293 if (minwait_secs != 0)
294 max_time_milliseconds = MIN(max_time_milliseconds,
295 (u_int)minwait_secs * 1000);
298 * if using client_alive, set the max timeout accordingly,
299 * and indicate that this particular timeout was for client
300 * alive by setting the client_alive_scheduled flag.
302 * this could be randomized somewhat to make traffic
303 * analysis more difficult, but we're not doing it yet.
306 max_time_milliseconds == 0 && options.client_alive_interval) {
307 client_alive_scheduled = 1;
308 max_time_milliseconds =
309 (u_int64_t)options.client_alive_interval * 1000;
314 /* wrong: bad condition XXX */
315 if (channel_not_very_much_buffered_data())
317 FD_SET(connection_in, *readsetp);
320 * Read packets from the client unless we have too much
321 * buffered stdin or channel data.
323 if (buffer_len(&stdin_buffer) < buffer_high &&
324 channel_not_very_much_buffered_data())
325 FD_SET(connection_in, *readsetp);
327 * If there is not too much data already buffered going to
328 * the client, try to get some more data from the program.
330 if (packet_not_very_much_data_to_write()) {
331 program_alive_scheduled = child_terminated;
333 FD_SET(fdout, *readsetp);
335 FD_SET(fderr, *readsetp);
338 * If we have buffered data, try to write some of that data
341 if (fdin != -1 && buffer_len(&stdin_buffer) > 0)
342 FD_SET(fdin, *writesetp);
344 notify_prepare(*readsetp);
347 * If we have buffered packet data going to the client, mark that
350 if (packet_have_data_to_write())
351 FD_SET(connection_out, *writesetp);
354 * If child has terminated and there is enough buffer space to read
355 * from it, then read as much as is available and exit.
357 if (child_terminated && packet_not_very_much_data_to_write())
358 if (max_time_milliseconds == 0 || client_alive_scheduled)
359 max_time_milliseconds = 100;
361 if (max_time_milliseconds == 0)
364 tv.tv_sec = max_time_milliseconds / 1000;
365 tv.tv_usec = 1000 * (max_time_milliseconds % 1000);
369 /* Wait for something to happen, or the timeout to expire. */
370 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
373 memset(*readsetp, 0, *nallocp);
374 memset(*writesetp, 0, *nallocp);
376 error("select: %.100s", strerror(errno));
378 if (ret == 0 && client_alive_scheduled)
379 client_alive_check();
380 if (!compat20 && program_alive_scheduled && fdin_is_tty) {
382 FD_SET(fdout, *readsetp);
384 FD_SET(fderr, *readsetp);
388 notify_done(*readsetp);
392 * Processes input from the client and the program. Input data is stored
393 * in buffers and processed later.
396 process_input(fd_set *readset)
401 /* Read and buffer any input data from the client. */
402 if (FD_ISSET(connection_in, readset)) {
404 len = roaming_read(connection_in, buf, sizeof(buf), &cont);
408 verbose("Connection closed by %.100s",
409 get_remote_ipaddr());
410 connection_closed = 1;
414 } else if (len < 0) {
415 if (errno != EINTR && errno != EAGAIN &&
416 errno != EWOULDBLOCK) {
417 verbose("Read error from remote host "
419 get_remote_ipaddr(), strerror(errno));
423 /* Buffer any received data. */
424 packet_process_incoming(buf, len);
430 /* Read and buffer any available stdout data from the program. */
431 if (!fdout_eof && FD_ISSET(fdout, readset)) {
433 len = read(fdout, buf, sizeof(buf));
434 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
435 errno == EWOULDBLOCK) && !child_terminated))) {
438 } else if (len <= 0) {
440 } else if ((!isatty(fdout) && len <= 0) ||
441 (isatty(fdout) && (len < 0 || (len == 0 && errno != 0)))) {
445 buffer_append(&stdout_buffer, buf, len);
449 /* Read and buffer any available stderr data from the program. */
450 if (!fderr_eof && FD_ISSET(fderr, readset)) {
452 len = read(fderr, buf, sizeof(buf));
453 if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
454 errno == EWOULDBLOCK) && !child_terminated))) {
457 } else if (len <= 0) {
459 } else if ((!isatty(fderr) && len <= 0) ||
460 (isatty(fderr) && (len < 0 || (len == 0 && errno != 0)))) {
464 buffer_append(&stderr_buffer, buf, len);
470 * Sends data from internal buffers to client program stdin.
473 process_output(fd_set *writeset)
480 /* Write buffered data to program stdin. */
481 if (!compat20 && fdin != -1 && FD_ISSET(fdin, writeset)) {
482 data = buffer_ptr(&stdin_buffer);
483 dlen = buffer_len(&stdin_buffer);
484 len = write(fdin, data, dlen);
486 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) {
488 } else if (len <= 0) {
492 shutdown(fdin, SHUT_WR); /* We will no longer send. */
495 /* Successful write. */
496 if (fdin_is_tty && dlen >= 1 && data[0] != '\r' &&
497 tcgetattr(fdin, &tio) == 0 &&
498 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
500 * Simulate echo to reduce the impact of
503 packet_send_ignore(len);
506 /* Consume the data from the buffer. */
507 buffer_consume(&stdin_buffer, len);
508 /* Update the count of bytes written to the program. */
512 /* Send any buffered packet data to the client. */
513 if (FD_ISSET(connection_out, writeset))
518 * Wait until all buffered output has been sent to the client.
519 * This is used when the program terminates.
524 /* Send any buffered stdout data to the client. */
525 if (buffer_len(&stdout_buffer) > 0) {
526 packet_start(SSH_SMSG_STDOUT_DATA);
527 packet_put_string(buffer_ptr(&stdout_buffer),
528 buffer_len(&stdout_buffer));
530 /* Update the count of sent bytes. */
531 stdout_bytes += buffer_len(&stdout_buffer);
533 /* Send any buffered stderr data to the client. */
534 if (buffer_len(&stderr_buffer) > 0) {
535 packet_start(SSH_SMSG_STDERR_DATA);
536 packet_put_string(buffer_ptr(&stderr_buffer),
537 buffer_len(&stderr_buffer));
539 /* Update the count of sent bytes. */
540 stderr_bytes += buffer_len(&stderr_buffer);
542 /* Wait until all buffered data has been written to the client. */
547 process_buffered_input_packets(void)
549 dispatch_run(DISPATCH_NONBLOCK, NULL, compat20 ? xxx_kex : NULL);
553 * Performs the interactive session. This handles data transmission between
554 * the client and the program. Note that the notion of stdin, stdout, and
555 * stderr in this function is sort of reversed: this function writes to
556 * stdin (of the child program), and reads from stdout and stderr (of the
560 server_loop(pid_t pid, int fdin_arg, int fdout_arg, int fderr_arg)
562 fd_set *readset = NULL, *writeset = NULL;
565 int wait_status; /* Status returned by wait(). */
566 pid_t wait_pid; /* pid returned by wait(). */
567 int waiting_termination = 0; /* Have displayed waiting close message. */
568 u_int64_t max_time_milliseconds;
569 u_int previous_stdout_buffer_bytes;
570 u_int stdout_buffer_bytes;
573 debug("Entering interactive session.");
575 /* Initialize the SIGCHLD kludge. */
576 child_terminated = 0;
577 mysignal(SIGCHLD, sigchld_handler);
580 signal(SIGTERM, sigterm_handler);
581 signal(SIGINT, sigterm_handler);
582 signal(SIGQUIT, sigterm_handler);
585 /* Initialize our global variables. */
593 /* we don't have stderr for interactive terminal sessions, see below */
597 if (!(datafellows & SSH_BUG_IGNOREMSG) && isatty(fdin))
600 connection_in = packet_get_connection_in();
601 connection_out = packet_get_connection_out();
605 previous_stdout_buffer_bytes = 0;
607 /* Set approximate I/O buffer size. */
608 if (packet_is_interactive())
611 buffer_high = 64 * 1024;
614 /* Initialize max_fd to the maximum of the known file descriptors. */
615 max_fd = MAX(connection_in, connection_out);
616 max_fd = MAX(max_fd, fdin);
617 max_fd = MAX(max_fd, fdout);
619 max_fd = MAX(max_fd, fderr);
622 /* Initialize Initialize buffers. */
623 buffer_init(&stdin_buffer);
624 buffer_init(&stdout_buffer);
625 buffer_init(&stderr_buffer);
628 * If we have no separate fderr (which is the case when we have a pty
629 * - there we cannot make difference between data sent to stdout and
630 * stderr), indicate that we have seen an EOF from stderr. This way
631 * we don't need to check the descriptor everywhere.
636 server_init_dispatch();
638 /* Main loop of the server for the interactive session mode. */
641 /* Process buffered packets from the client. */
642 process_buffered_input_packets();
645 * If we have received eof, and there is no more pending
646 * input data, cause a real eof by closing fdin.
648 if (stdin_eof && fdin != -1 && buffer_len(&stdin_buffer) == 0) {
652 shutdown(fdin, SHUT_WR); /* We will no longer send. */
655 /* Make packets from buffered stderr data to send to the client. */
656 make_packets_from_stderr_data();
659 * Make packets from buffered stdout data to send to the
660 * client. If there is very little to send, this arranges to
661 * not send them now, but to wait a short while to see if we
662 * are getting more data. This is necessary, as some systems
663 * wake up readers from a pty after each separate character.
665 max_time_milliseconds = 0;
666 stdout_buffer_bytes = buffer_len(&stdout_buffer);
667 if (stdout_buffer_bytes != 0 && stdout_buffer_bytes < 256 &&
668 stdout_buffer_bytes != previous_stdout_buffer_bytes) {
669 /* try again after a while */
670 max_time_milliseconds = 10;
673 make_packets_from_stdout_data();
675 previous_stdout_buffer_bytes = buffer_len(&stdout_buffer);
677 /* Send channel data to the client. */
678 if (packet_not_very_much_data_to_write())
679 channel_output_poll();
682 * Bail out of the loop if the program has closed its output
683 * descriptors, and we have no more data to send to the
684 * client, and there is no pending buffered data.
686 if (fdout_eof && fderr_eof && !packet_have_data_to_write() &&
687 buffer_len(&stdout_buffer) == 0 && buffer_len(&stderr_buffer) == 0) {
688 if (!channel_still_open())
690 if (!waiting_termination) {
691 const char *s = "Waiting for forwarded connections to terminate...\r\n";
693 waiting_termination = 1;
694 buffer_append(&stderr_buffer, s, strlen(s));
696 /* Display list of open channels. */
697 cp = channel_open_message();
698 buffer_append(&stderr_buffer, cp, strlen(cp));
702 max_fd = MAX(connection_in, connection_out);
703 max_fd = MAX(max_fd, fdin);
704 max_fd = MAX(max_fd, fdout);
705 max_fd = MAX(max_fd, fderr);
706 max_fd = MAX(max_fd, notify_pipe[0]);
708 /* Sleep in select() until we can do something. */
709 wait_until_can_do_something(&readset, &writeset, &max_fd,
710 &nalloc, max_time_milliseconds);
712 if (received_sigterm) {
713 logit("Exiting on signal %d", (int)received_sigterm);
714 /* Clean up sessions, utmp, etc. */
718 /* Process any channel events. */
719 channel_after_select(readset, writeset);
721 /* Process input from the client and from program stdout/stderr. */
722 process_input(readset);
724 /* Process output to the client and to program stdin. */
725 process_output(writeset);
730 /* Cleanup and termination code. */
732 /* Wait until all output has been sent to the client. */
735 debug("End of interactive session; stdin %ld, stdout (read %ld, sent %ld), stderr %ld bytes.",
736 stdin_bytes, fdout_bytes, stdout_bytes, stderr_bytes);
738 /* Free and clear the buffers. */
739 buffer_free(&stdin_buffer);
740 buffer_free(&stdout_buffer);
741 buffer_free(&stderr_buffer);
743 /* Close the file descriptors. */
758 /* We no longer want our SIGCHLD handler to be called. */
759 mysignal(SIGCHLD, SIG_DFL);
761 while ((wait_pid = waitpid(-1, &wait_status, 0)) < 0)
763 packet_disconnect("wait: %.100s", strerror(errno));
765 error("Strange, wait returned pid %ld, expected %ld",
766 (long)wait_pid, (long)pid);
768 /* Check if it exited normally. */
769 if (WIFEXITED(wait_status)) {
770 /* Yes, normal exit. Get exit status and send it to the client. */
771 debug("Command exited with status %d.", WEXITSTATUS(wait_status));
772 packet_start(SSH_SMSG_EXITSTATUS);
773 packet_put_int(WEXITSTATUS(wait_status));
778 * Wait for exit confirmation. Note that there might be
779 * other packets coming before it; however, the program has
780 * already died so we just ignore them. The client is
781 * supposed to respond with the confirmation when it receives
785 type = packet_read();
787 while (type != SSH_CMSG_EXIT_CONFIRMATION);
789 debug("Received exit confirmation.");
792 /* Check if the program terminated due to a signal. */
793 if (WIFSIGNALED(wait_status))
794 packet_disconnect("Command terminated on signal %d.",
795 WTERMSIG(wait_status));
797 /* Some weird exit cause. Just exit. */
798 packet_disconnect("wait returned status %04x.", wait_status);
803 collect_children(void)
809 /* block SIGCHLD while we check for dead children */
811 sigaddset(&nset, SIGCHLD);
812 sigprocmask(SIG_BLOCK, &nset, &oset);
813 if (child_terminated) {
814 debug("Received SIGCHLD.");
815 while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
816 (pid < 0 && errno == EINTR))
818 session_close_by_pid(pid, status);
819 child_terminated = 0;
821 sigprocmask(SIG_SETMASK, &oset, NULL);
825 server_loop2(Authctxt *authctxt)
827 fd_set *readset = NULL, *writeset = NULL;
828 int rekeying = 0, max_fd;
830 u_int64_t rekey_timeout_ms = 0;
832 debug("Entering interactive session for SSH2.");
834 mysignal(SIGCHLD, sigchld_handler);
835 child_terminated = 0;
836 connection_in = packet_get_connection_in();
837 connection_out = packet_get_connection_out();
840 signal(SIGTERM, sigterm_handler);
841 signal(SIGINT, sigterm_handler);
842 signal(SIGQUIT, sigterm_handler);
847 max_fd = MAX(connection_in, connection_out);
848 max_fd = MAX(max_fd, notify_pipe[0]);
850 server_init_dispatch();
853 process_buffered_input_packets();
855 rekeying = (xxx_kex != NULL && !xxx_kex->done);
857 if (!rekeying && packet_not_very_much_data_to_write())
858 channel_output_poll();
859 if (options.rekey_interval > 0 && compat20 && !rekeying)
860 rekey_timeout_ms = packet_get_rekey_timeout() * 1000;
862 rekey_timeout_ms = 0;
864 wait_until_can_do_something(&readset, &writeset, &max_fd,
865 &nalloc, rekey_timeout_ms);
867 if (received_sigterm) {
868 logit("Exiting on signal %d", (int)received_sigterm);
869 /* Clean up sessions, utmp, etc. */
875 channel_after_select(readset, writeset);
876 if (packet_need_rekeying()) {
877 debug("need rekeying");
879 kex_send_kexinit(xxx_kex);
882 process_input(readset);
883 if (connection_closed)
885 process_output(writeset);
892 /* free all channels, no more reads and writes */
895 /* free remaining sessions, e.g. remove wtmp entries */
896 session_destroy_all(NULL);
900 server_input_keep_alive(int type, u_int32_t seq, void *ctxt)
902 debug("Got %d/%u for keepalive", type, seq);
904 * reset timeout, since we got a sane answer from the client.
905 * even if this was generated by something other than
906 * the bogus CHANNEL_REQUEST we send for keepalives.
908 packet_set_alive_timeouts(0);
912 server_input_stdin_data(int type, u_int32_t seq, void *ctxt)
917 /* Stdin data from the client. Append it to the buffer. */
918 /* Ignore any data if the client has closed stdin. */
921 data = packet_get_string(&data_len);
923 buffer_append(&stdin_buffer, data, data_len);
924 explicit_bzero(data, data_len);
929 server_input_eof(int type, u_int32_t seq, void *ctxt)
932 * Eof from the client. The stdin descriptor to the
933 * program will be closed when all buffered data has
936 debug("EOF received for stdin.");
942 server_input_window_size(int type, u_int32_t seq, void *ctxt)
944 u_int row = packet_get_int();
945 u_int col = packet_get_int();
946 u_int xpixel = packet_get_int();
947 u_int ypixel = packet_get_int();
949 debug("Window change received.");
952 pty_change_window_size(fdin, row, col, xpixel, ypixel);
956 server_request_direct_tcpip(void)
959 char *target, *originator;
960 u_short target_port, originator_port;
962 target = packet_get_string(NULL);
963 target_port = packet_get_int();
964 originator = packet_get_string(NULL);
965 originator_port = packet_get_int();
968 debug("server_request_direct_tcpip: originator %s port %d, target %s "
969 "port %d", originator, originator_port, target, target_port);
971 /* XXX fine grained permissions */
972 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
973 !no_port_forwarding_flag) {
974 c = channel_connect_to(target, target_port,
975 "direct-tcpip", "direct-tcpip");
977 logit("refused local port forward: "
978 "originator %s port %d, target %s port %d",
979 originator, originator_port, target, target_port);
989 server_request_tun(void)
995 mode = packet_get_int();
997 case SSH_TUNMODE_POINTOPOINT:
998 case SSH_TUNMODE_ETHERNET:
1001 packet_send_debug("Unsupported tunnel device mode.");
1004 if ((options.permit_tun & mode) == 0) {
1005 packet_send_debug("Server has rejected tunnel device "
1010 tun = packet_get_int();
1011 if (forced_tun_device != -1) {
1012 if (tun != SSH_TUNID_ANY && forced_tun_device != tun)
1014 tun = forced_tun_device;
1016 sock = tun_open(tun, mode);
1019 if (options.hpn_disabled)
1020 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1021 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
1024 c = channel_new("tun", SSH_CHANNEL_OPEN, sock, sock, -1,
1025 options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0,
1028 #if defined(SSH_TUN_FILTER)
1029 if (mode == SSH_TUNMODE_POINTOPOINT)
1030 channel_register_filter(c->self, sys_tun_infilter,
1031 sys_tun_outfilter, NULL, NULL);
1036 packet_send_debug("Failed to open the tunnel device.");
1041 server_request_session(void)
1045 debug("input_session_request");
1048 if (no_more_sessions) {
1049 packet_disconnect("Possible attack: attempt to open a session "
1050 "after additional sessions disabled");
1054 * A server session has no fd to read or write until a
1055 * CHANNEL_REQUEST for a shell is made, so we set the type to
1056 * SSH_CHANNEL_LARVAL. Additionally, a callback for handling all
1057 * CHANNEL_REQUEST messages is registered.
1059 c = channel_new("session", SSH_CHANNEL_LARVAL,
1060 -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
1061 0, "server-session", 1);
1062 if (!options.hpn_disabled && options.tcp_rcv_buf_poll)
1063 c->dynamic_window = 1;
1064 if (session_open(the_authctxt, c->self) != 1) {
1065 debug("session open failed, free channel %d", c->self);
1069 channel_register_cleanup(c->self, session_close_by_channel, 0);
1074 server_input_channel_open(int type, u_int32_t seq, void *ctxt)
1079 u_int rmaxpack, rwindow, len;
1081 ctype = packet_get_string(&len);
1082 rchan = packet_get_int();
1083 rwindow = packet_get_int();
1084 rmaxpack = packet_get_int();
1086 debug("server_input_channel_open: ctype %s rchan %d win %d max %d",
1087 ctype, rchan, rwindow, rmaxpack);
1089 if (strcmp(ctype, "session") == 0) {
1090 c = server_request_session();
1091 } else if (strcmp(ctype, "direct-tcpip") == 0) {
1092 c = server_request_direct_tcpip();
1093 } else if (strcmp(ctype, "tun@openssh.com") == 0) {
1094 c = server_request_tun();
1097 debug("server_input_channel_open: confirm %s", ctype);
1098 c->remote_id = rchan;
1099 c->remote_window = rwindow;
1100 c->remote_maxpacket = rmaxpack;
1101 if (c->type != SSH_CHANNEL_CONNECTING) {
1102 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1103 packet_put_int(c->remote_id);
1104 packet_put_int(c->self);
1105 packet_put_int(c->local_window);
1106 packet_put_int(c->local_maxpacket);
1110 debug("server_input_channel_open: failure %s", ctype);
1111 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1112 packet_put_int(rchan);
1113 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1114 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1115 packet_put_cstring("open failed");
1116 packet_put_cstring("");
1124 server_input_global_request(int type, u_int32_t seq, void *ctxt)
1128 int success = 0, allocated_listen_port = 0;
1130 rtype = packet_get_string(NULL);
1131 want_reply = packet_get_char();
1132 debug("server_input_global_request: rtype %s want_reply %d", rtype, want_reply);
1134 /* -R style forwarding */
1135 if (strcmp(rtype, "tcpip-forward") == 0) {
1137 char *listen_address;
1138 u_short listen_port;
1140 pw = the_authctxt->pw;
1141 if (pw == NULL || !the_authctxt->valid)
1142 fatal("server_input_global_request: no/invalid user");
1143 listen_address = packet_get_string(NULL);
1144 listen_port = (u_short)packet_get_int();
1145 debug("server_input_global_request: tcpip-forward listen %s port %d",
1146 listen_address, listen_port);
1148 /* check permissions */
1149 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0 ||
1150 no_port_forwarding_flag ||
1151 (!want_reply && listen_port == 0)
1152 #ifndef NO_IPPORT_RESERVED_CONCEPT
1153 || (listen_port != 0 && listen_port < IPPORT_RESERVED &&
1158 packet_send_debug("Server has disabled port forwarding.");
1160 /* Start listening on the port */
1161 success = channel_setup_remote_fwd_listener(
1162 listen_address, listen_port,
1163 &allocated_listen_port, options.gateway_ports);
1165 free(listen_address);
1166 } else if (strcmp(rtype, "cancel-tcpip-forward") == 0) {
1167 char *cancel_address;
1168 u_short cancel_port;
1170 cancel_address = packet_get_string(NULL);
1171 cancel_port = (u_short)packet_get_int();
1172 debug("%s: cancel-tcpip-forward addr %s port %d", __func__,
1173 cancel_address, cancel_port);
1175 success = channel_cancel_rport_listener(cancel_address,
1177 free(cancel_address);
1178 } else if (strcmp(rtype, "no-more-sessions@openssh.com") == 0) {
1179 no_more_sessions = 1;
1183 packet_start(success ?
1184 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1185 if (success && allocated_listen_port > 0)
1186 packet_put_int(allocated_listen_port);
1188 packet_write_wait();
1194 server_input_channel_req(int type, u_int32_t seq, void *ctxt)
1197 int id, reply, success = 0;
1200 id = packet_get_int();
1201 rtype = packet_get_string(NULL);
1202 reply = packet_get_char();
1204 debug("server_input_channel_req: channel %d request %s reply %d",
1207 if ((c = channel_lookup(id)) == NULL)
1208 packet_disconnect("server_input_channel_req: "
1209 "unknown channel %d", id);
1210 if (!strcmp(rtype, "eow@openssh.com")) {
1213 } else if ((c->type == SSH_CHANNEL_LARVAL ||
1214 c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
1215 success = session_input_channel_req(c, rtype);
1217 packet_start(success ?
1218 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1219 packet_put_int(c->remote_id);
1226 server_init_dispatch_20(void)
1228 debug("server_init_dispatch_20");
1229 dispatch_init(&dispatch_protocol_error);
1230 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1231 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1232 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1233 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1234 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &server_input_channel_open);
1235 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1236 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1237 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &server_input_channel_req);
1238 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1239 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &server_input_global_request);
1241 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &server_input_keep_alive);
1242 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &server_input_keep_alive);
1243 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &server_input_keep_alive);
1244 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &server_input_keep_alive);
1246 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1249 server_init_dispatch_13(void)
1251 debug("server_init_dispatch_13");
1252 dispatch_init(NULL);
1253 dispatch_set(SSH_CMSG_EOF, &server_input_eof);
1254 dispatch_set(SSH_CMSG_STDIN_DATA, &server_input_stdin_data);
1255 dispatch_set(SSH_CMSG_WINDOW_SIZE, &server_input_window_size);
1256 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1257 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1258 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1259 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1260 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1261 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1264 server_init_dispatch_15(void)
1266 server_init_dispatch_13();
1267 debug("server_init_dispatch_15");
1268 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1269 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_oclose);
1272 server_init_dispatch(void)
1275 server_init_dispatch_20();
1277 server_init_dispatch_13();
1279 server_init_dispatch_15();