2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * The main loop for the interactive session (client side).
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".
14 * Copyright (c) 1999 Theo de Raadt. 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.
37 * SSH2 support added by Markus Friedl.
38 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved.
40 * Redistribution and use in source and binary forms, with or without
41 * modification, are permitted provided that the following conditions
43 * 1. Redistributions of source code must retain the above copyright
44 * notice, this list of conditions and the following disclaimer.
45 * 2. Redistributions in binary form must reproduce the above copyright
46 * notice, this list of conditions and the following disclaimer in the
47 * documentation and/or other materials provided with the distribution.
49 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
50 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
51 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
52 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
53 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
54 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
55 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
56 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
57 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
58 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
62 RCSID("$OpenBSD: clientloop.c,v 1.117 2003/12/16 15:49:51 markus Exp $");
79 #include "clientloop.h"
87 extern Options options
;
89 /* Flag indicating that stdin should be redirected from /dev/null. */
90 extern int stdin_null_flag
;
92 /* Flag indicating that no shell has been requested */
93 extern int no_shell_flag
;
96 * Name of the host we are connecting to. This is the name given on the
97 * command line, or the HostName specified for the user-supplied name in a
103 * Flag to indicate that we have received a window change signal which has
104 * not yet been processed. This will cause a message indicating the new
105 * window size to be sent to the server a little later. This is volatile
106 * because this is updated in a signal handler.
108 static volatile sig_atomic_t received_window_change_signal
= 0;
109 static volatile sig_atomic_t received_signal
= 0;
111 /* Flag indicating whether the user\'s terminal is in non-blocking mode. */
112 static int in_non_blocking_mode
= 0;
114 /* Common data for the client loop code. */
115 static int quit_pending
; /* Set to non-zero to quit the client loop. */
116 static int escape_char
; /* Escape character. */
117 static int escape_pending
; /* Last character was the escape character */
118 static int last_was_cr
; /* Last character was a newline. */
119 static int exit_status
; /* Used to store the exit status of the command. */
120 static int stdin_eof
; /* EOF has been encountered on standard error. */
121 static Buffer stdin_buffer
; /* Buffer for stdin data. */
122 static Buffer stdout_buffer
; /* Buffer for stdout data. */
123 static Buffer stderr_buffer
; /* Buffer for stderr data. */
124 static u_long stdin_bytes
, stdout_bytes
, stderr_bytes
;
125 static u_int buffer_high
;/* Soft max buffer size. */
126 static int connection_in
; /* Connection to server (input). */
127 static int connection_out
; /* Connection to server (output). */
128 static int need_rekeying
; /* Set to non-zero if rekeying is requested. */
129 static int session_closed
= 0; /* In SSH2: login session closed. */
130 static int server_alive_timeouts
= 0;
132 static void client_init_dispatch(void);
133 int session_ident
= -1;
138 /* Restores stdin to blocking mode. */
141 leave_non_blocking(void)
143 if (in_non_blocking_mode
) {
144 (void) fcntl(fileno(stdin
), F_SETFL
, 0);
145 in_non_blocking_mode
= 0;
149 /* Puts stdin terminal in non-blocking mode. */
152 enter_non_blocking(void)
154 in_non_blocking_mode
= 1;
155 (void) fcntl(fileno(stdin
), F_SETFL
, O_NONBLOCK
);
159 * Signal handler for the window change signal (SIGWINCH). This just sets a
160 * flag indicating that the window has changed.
164 window_change_handler(int sig
)
166 received_window_change_signal
= 1;
167 signal(SIGWINCH
, window_change_handler
);
171 * Signal handler for signals that cause the program to terminate. These
172 * signals must be trapped to restore terminal modes.
176 signal_handler(int sig
)
178 received_signal
= sig
;
183 * Returns current time in seconds from Jan 1, 1970 with the maximum
184 * available resolution.
188 get_current_time(void)
191 gettimeofday(&tv
, NULL
);
192 return (double) tv
.tv_sec
+ (double) tv
.tv_usec
/ 1000000.0;
196 * This is called when the interactive is entered. This checks if there is
197 * an EOF coming on stdin. We must check this explicitly, as select() does
198 * not appear to wake up when redirecting from /dev/null.
202 client_check_initial_eof_on_stdin(void)
208 * If standard input is to be "redirected from /dev/null", we simply
209 * mark that we have seen an EOF and send an EOF message to the
210 * server. Otherwise, we try to read a single character; it appears
211 * that for some files, such /dev/null, select() never wakes up for
212 * read for this descriptor, which means that we never get EOF. This
213 * way we will get the EOF if stdin comes from /dev/null or similar.
215 if (stdin_null_flag
) {
216 /* Fake EOF on stdin. */
217 debug("Sending eof.");
219 packet_start(SSH_CMSG_EOF
);
222 enter_non_blocking();
224 /* Check for immediate EOF on stdin. */
225 len
= read(fileno(stdin
), buf
, 1);
227 /* EOF. Record that we have seen it and send EOF to server. */
228 debug("Sending eof.");
230 packet_start(SSH_CMSG_EOF
);
232 } else if (len
> 0) {
234 * Got data. We must store the data in the buffer,
235 * and also process it as an escape character if
238 if ((u_char
) buf
[0] == escape_char
)
241 buffer_append(&stdin_buffer
, buf
, 1);
243 leave_non_blocking();
249 * Make packets from buffered stdin data, and buffer them for sending to the
254 client_make_packets_from_stdin_data(void)
258 /* Send buffered stdin data to the server. */
259 while (buffer_len(&stdin_buffer
) > 0 &&
260 packet_not_very_much_data_to_write()) {
261 len
= buffer_len(&stdin_buffer
);
262 /* Keep the packets at reasonable size. */
263 if (len
> packet_get_maxsize())
264 len
= packet_get_maxsize();
265 packet_start(SSH_CMSG_STDIN_DATA
);
266 packet_put_string(buffer_ptr(&stdin_buffer
), len
);
268 buffer_consume(&stdin_buffer
, len
);
270 /* If we have a pending EOF, send it now. */
271 if (stdin_eof
&& buffer_len(&stdin_buffer
) == 0) {
272 packet_start(SSH_CMSG_EOF
);
279 * Checks if the client window has changed, and sends a packet about it to
280 * the server if so. The actual change is detected elsewhere (by a software
281 * interrupt on Unix); this just checks the flag and sends a message if
286 client_check_window_change(void)
290 if (! received_window_change_signal
)
293 received_window_change_signal
= 0;
295 if (ioctl(fileno(stdin
), TIOCGWINSZ
, &ws
) < 0)
298 debug2("client_check_window_change: changed");
301 channel_request_start(session_ident
, "window-change", 0);
302 packet_put_int(ws
.ws_col
);
303 packet_put_int(ws
.ws_row
);
304 packet_put_int(ws
.ws_xpixel
);
305 packet_put_int(ws
.ws_ypixel
);
308 packet_start(SSH_CMSG_WINDOW_SIZE
);
309 packet_put_int(ws
.ws_row
);
310 packet_put_int(ws
.ws_col
);
311 packet_put_int(ws
.ws_xpixel
);
312 packet_put_int(ws
.ws_ypixel
);
318 client_global_request_reply(int type
, u_int32_t seq
, void *ctxt
)
320 server_alive_timeouts
= 0;
321 client_global_request_reply_fwd(type
, seq
, ctxt
);
325 server_alive_check(void)
327 if (++server_alive_timeouts
> options
.server_alive_count_max
)
328 packet_disconnect("Timeout, server not responding.");
329 packet_start(SSH2_MSG_GLOBAL_REQUEST
);
330 packet_put_cstring("keepalive@openssh.com");
331 packet_put_char(1); /* boolean: want reply */
336 * Waits until the client can do something (some data becomes available on
337 * one of the file descriptors).
341 client_wait_until_can_do_something(fd_set
**readsetp
, fd_set
**writesetp
,
342 int *maxfdp
, int *nallocp
, int rekeying
)
344 struct timeval tv
, *tvp
;
347 /* Add any selections by the channel mechanism. */
348 channel_prepare_select(readsetp
, writesetp
, maxfdp
, nallocp
, rekeying
);
351 /* Read from the connection, unless our buffers are full. */
352 if (buffer_len(&stdout_buffer
) < buffer_high
&&
353 buffer_len(&stderr_buffer
) < buffer_high
&&
354 channel_not_very_much_buffered_data())
355 FD_SET(connection_in
, *readsetp
);
357 * Read from stdin, unless we have seen EOF or have very much
358 * buffered data to send to the server.
360 if (!stdin_eof
&& packet_not_very_much_data_to_write())
361 FD_SET(fileno(stdin
), *readsetp
);
363 /* Select stdout/stderr if have data in buffer. */
364 if (buffer_len(&stdout_buffer
) > 0)
365 FD_SET(fileno(stdout
), *writesetp
);
366 if (buffer_len(&stderr_buffer
) > 0)
367 FD_SET(fileno(stderr
), *writesetp
);
369 /* channel_prepare_select could have closed the last channel */
370 if (session_closed
&& !channel_still_open() &&
371 !packet_have_data_to_write()) {
372 /* clear mask since we did not call select() */
373 memset(*readsetp
, 0, *nallocp
);
374 memset(*writesetp
, 0, *nallocp
);
377 FD_SET(connection_in
, *readsetp
);
381 /* Select server connection if have data to write to the server. */
382 if (packet_have_data_to_write())
383 FD_SET(connection_out
, *writesetp
);
386 * Wait for something to happen. This will suspend the process until
387 * some selected descriptor can be read, written, or has some other
391 if (options
.server_alive_interval
== 0 || !compat20
)
394 tv
.tv_sec
= options
.server_alive_interval
;
398 ret
= select((*maxfdp
)+1, *readsetp
, *writesetp
, NULL
, tvp
);
403 * We have to clear the select masks, because we return.
404 * We have to return, because the mainloop checks for the flags
405 * set by the signal handlers.
407 memset(*readsetp
, 0, *nallocp
);
408 memset(*writesetp
, 0, *nallocp
);
412 /* Note: we might still have data in the buffers. */
413 snprintf(buf
, sizeof buf
, "select: %s\r\n", strerror(errno
));
414 buffer_append(&stderr_buffer
, buf
, strlen(buf
));
417 server_alive_check();
421 client_suspend_self(Buffer
*bin
, Buffer
*bout
, Buffer
*berr
)
423 struct winsize oldws
, newws
;
425 /* Flush stdout and stderr buffers. */
426 if (buffer_len(bout
) > 0)
427 atomicio(vwrite
, fileno(stdout
), buffer_ptr(bout
), buffer_len(bout
));
428 if (buffer_len(berr
) > 0)
429 atomicio(vwrite
, fileno(stderr
), buffer_ptr(berr
), buffer_len(berr
));
434 * Free (and clear) the buffer to reduce the amount of data that gets
441 /* Save old window size. */
442 ioctl(fileno(stdin
), TIOCGWINSZ
, &oldws
);
444 /* Send the suspend signal to the program itself. */
445 kill(getpid(), SIGTSTP
);
447 /* Check if the window size has changed. */
448 if (ioctl(fileno(stdin
), TIOCGWINSZ
, &newws
) >= 0 &&
449 (oldws
.ws_row
!= newws
.ws_row
||
450 oldws
.ws_col
!= newws
.ws_col
||
451 oldws
.ws_xpixel
!= newws
.ws_xpixel
||
452 oldws
.ws_ypixel
!= newws
.ws_ypixel
))
453 received_window_change_signal
= 1;
455 /* OK, we have been continued by the user. Reinitialize buffers. */
464 client_process_net_input(fd_set
* readset
)
470 * Read input from the server, and add any such data to the buffer of
471 * the packet subsystem.
473 if (FD_ISSET(connection_in
, readset
)) {
474 /* Read as much as possible. */
475 len
= read(connection_in
, buf
, sizeof(buf
));
477 /* Received EOF. The remote host has closed the connection. */
478 snprintf(buf
, sizeof buf
, "Connection to %.300s closed by remote host.\r\n",
480 buffer_append(&stderr_buffer
, buf
, strlen(buf
));
485 * There is a kernel bug on Solaris that causes select to
486 * sometimes wake up even though there is no data available.
488 if (len
< 0 && (errno
== EAGAIN
|| errno
== EINTR
))
492 /* An error has encountered. Perhaps there is a network problem. */
493 snprintf(buf
, sizeof buf
, "Read from remote host %.300s: %.100s\r\n",
494 host
, strerror(errno
));
495 buffer_append(&stderr_buffer
, buf
, strlen(buf
));
499 packet_process_incoming(buf
, len
);
504 process_cmdline(void)
506 void (*handler
)(int);
508 u_short fwd_port
, fwd_host_port
;
509 char buf
[1024], sfwd_port
[6], sfwd_host_port
[6];
513 handler
= signal(SIGINT
, SIG_IGN
);
514 cmd
= s
= read_passphrase("\r\nssh> ", RP_ECHO
);
517 while (*s
&& isspace(*s
))
521 if (strlen(s
) < 2 || s
[0] != '-' || !(s
[1] == 'L' || s
[1] == 'R')) {
522 logit("Invalid command.");
527 if (!local
&& !compat20
) {
528 logit("Not supported for SSH protocol version 1.");
532 while (*s
&& isspace(*s
))
535 if (sscanf(s
, "%5[0-9]:%255[^:]:%5[0-9]",
536 sfwd_port
, buf
, sfwd_host_port
) != 3 &&
537 sscanf(s
, "%5[0-9]/%255[^/]/%5[0-9]",
538 sfwd_port
, buf
, sfwd_host_port
) != 3) {
539 logit("Bad forwarding specification.");
542 if ((fwd_port
= a2port(sfwd_port
)) == 0 ||
543 (fwd_host_port
= a2port(sfwd_host_port
)) == 0) {
544 logit("Bad forwarding port(s).");
548 if (channel_setup_local_fwd_listener(fwd_port
, buf
,
549 fwd_host_port
, options
.gateway_ports
) < 0) {
550 logit("Port forwarding failed.");
554 channel_request_remote_forwarding(fwd_port
, buf
,
556 logit("Forwarding port.");
558 signal(SIGINT
, handler
);
564 /* process the characters one by one */
566 process_escapes(Buffer
*bin
, Buffer
*bout
, Buffer
*berr
, char *buf
, int len
)
575 for (i
= 0; i
< len
; i
++) {
576 /* Get one character at a time. */
579 if (escape_pending
) {
580 /* We have previously seen an escape character. */
581 /* Clear the flag now. */
584 /* Process the escaped character. */
587 /* Terminate the connection. */
588 snprintf(string
, sizeof string
, "%c.\r\n", escape_char
);
589 buffer_append(berr
, string
, strlen(string
));
595 /* Suspend the program. */
596 /* Print a message to that effect to the user. */
597 snprintf(string
, sizeof string
, "%c^Z [suspend ssh]\r\n", escape_char
);
598 buffer_append(berr
, string
, strlen(string
));
600 /* Restore terminal modes and suspend. */
601 client_suspend_self(bin
, bout
, berr
);
603 /* We have been continued. */
608 snprintf(string
, sizeof string
,
609 "%cB\r\n", escape_char
);
610 buffer_append(berr
, string
,
612 channel_request_start(session_ident
,
614 packet_put_int(1000);
621 if (datafellows
& SSH_BUG_NOREKEY
)
622 logit("Server does not support re-keying");
630 * Detach the program (continue to serve connections,
631 * but put in background and no more new connections).
633 /* Restore tty modes. */
636 /* Stop listening for new connections. */
637 channel_stop_listening();
639 snprintf(string
, sizeof string
,
640 "%c& [backgrounded]\n", escape_char
);
641 buffer_append(berr
, string
, strlen(string
));
643 /* Fork into background. */
646 error("fork: %.100s", strerror(errno
));
649 if (pid
!= 0) { /* This is the parent. */
650 /* The parent just exits. */
653 /* The child continues serving connections. */
655 buffer_append(bin
, "\004", 1);
656 /* fake EOF on stdin */
658 } else if (!stdin_eof
) {
660 * Sending SSH_CMSG_EOF alone does not always appear
661 * to be enough. So we try to send an EOF character
664 packet_start(SSH_CMSG_STDIN_DATA
);
665 packet_put_string("\004", 1);
669 if (buffer_len(bin
) == 0) {
670 packet_start(SSH_CMSG_EOF
);
677 snprintf(string
, sizeof string
,
679 Supported escape sequences:\r\n\
680 %c. - terminate connection\r\n\
681 %cB - send a BREAK to the remote system\r\n\
682 %cC - open a command line\r\n\
683 %cR - Request rekey (SSH protocol 2 only)\r\n\
684 %c^Z - suspend ssh\r\n\
685 %c# - list forwarded connections\r\n\
686 %c& - background ssh (when waiting for connections to terminate)\r\n\
687 %c? - this message\r\n\
688 %c%c - send the escape character by typing it twice\r\n\
689 (Note that escapes are only recognized immediately after newline.)\r\n",
690 escape_char
, escape_char
, escape_char
, escape_char
,
691 escape_char
, escape_char
, escape_char
, escape_char
,
692 escape_char
, escape_char
, escape_char
);
693 buffer_append(berr
, string
, strlen(string
));
697 snprintf(string
, sizeof string
, "%c#\r\n", escape_char
);
698 buffer_append(berr
, string
, strlen(string
));
699 s
= channel_open_message();
700 buffer_append(berr
, s
, strlen(s
));
709 if (ch
!= escape_char
) {
710 buffer_put_char(bin
, escape_char
);
713 /* Escaped characters fall through here */
718 * The previous character was not an escape char. Check if this
721 if (last_was_cr
&& ch
== escape_char
) {
722 /* It is. Set the flag and continue to next character. */
729 * Normal character. Record whether it was a newline,
730 * and append it to the buffer.
732 last_was_cr
= (ch
== '\r' || ch
== '\n');
733 buffer_put_char(bin
, ch
);
740 client_process_input(fd_set
* readset
)
745 /* Read input from stdin. */
746 if (FD_ISSET(fileno(stdin
), readset
)) {
747 /* Read as much as possible. */
748 len
= read(fileno(stdin
), buf
, sizeof(buf
));
749 if (len
< 0 && (errno
== EAGAIN
|| errno
== EINTR
))
750 return; /* we'll try again later */
753 * Received EOF or error. They are treated
754 * similarly, except that an error message is printed
755 * if it was an error condition.
758 snprintf(buf
, sizeof buf
, "read: %.100s\r\n", strerror(errno
));
759 buffer_append(&stderr_buffer
, buf
, strlen(buf
));
761 /* Mark that we have seen EOF. */
764 * Send an EOF message to the server unless there is
765 * data in the buffer. If there is data in the
766 * buffer, no message will be sent now. Code
767 * elsewhere will send the EOF when the buffer
768 * becomes empty if stdin_eof is set.
770 if (buffer_len(&stdin_buffer
) == 0) {
771 packet_start(SSH_CMSG_EOF
);
774 } else if (escape_char
== SSH_ESCAPECHAR_NONE
) {
776 * Normal successful read, and no escape character.
777 * Just append the data to buffer.
779 buffer_append(&stdin_buffer
, buf
, len
);
782 * Normal, successful read. But we have an escape character
783 * and have to process the characters one by one.
785 if (process_escapes(&stdin_buffer
, &stdout_buffer
,
786 &stderr_buffer
, buf
, len
) == -1)
793 client_process_output(fd_set
* writeset
)
798 /* Write buffered output to stdout. */
799 if (FD_ISSET(fileno(stdout
), writeset
)) {
800 /* Write as much data as possible. */
801 len
= write(fileno(stdout
), buffer_ptr(&stdout_buffer
),
802 buffer_len(&stdout_buffer
));
804 if (errno
== EINTR
|| errno
== EAGAIN
)
808 * An error or EOF was encountered. Put an
809 * error message to stderr buffer.
811 snprintf(buf
, sizeof buf
, "write stdout: %.50s\r\n", strerror(errno
));
812 buffer_append(&stderr_buffer
, buf
, strlen(buf
));
817 /* Consume printed data from the buffer. */
818 buffer_consume(&stdout_buffer
, len
);
821 /* Write buffered output to stderr. */
822 if (FD_ISSET(fileno(stderr
), writeset
)) {
823 /* Write as much data as possible. */
824 len
= write(fileno(stderr
), buffer_ptr(&stderr_buffer
),
825 buffer_len(&stderr_buffer
));
827 if (errno
== EINTR
|| errno
== EAGAIN
)
830 /* EOF or error, but can't even print error message. */
835 /* Consume printed characters from the buffer. */
836 buffer_consume(&stderr_buffer
, len
);
842 * Get packets from the connection input buffer, and process them as long as
843 * there are packets available.
845 * Any unknown packets received during the actual
846 * session cause the session to terminate. This is
847 * intended to make debugging easier since no
848 * confirmations are sent. Any compatible protocol
849 * extensions must be negotiated during the
854 client_process_buffered_input_packets(void)
856 dispatch_run(DISPATCH_NONBLOCK
, &quit_pending
, compat20
? xxx_kex
: NULL
);
859 /* scan buf[] for '~' before sending data to the peer */
862 simple_escape_filter(Channel
*c
, char *buf
, int len
)
864 /* XXX we assume c->extended is writeable */
865 return process_escapes(&c
->input
, &c
->output
, &c
->extended
, buf
, len
);
869 client_channel_closed(int id
, void *arg
)
871 if (id
!= session_ident
)
872 error("client_channel_closed: id %d != session_ident %d",
874 channel_cancel_cleanup(id
);
880 * Implements the interactive session with the server. This is called after
881 * the user has been authenticated, and a command has been started on the
882 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character
883 * used as an escape character for terminating or suspending the session.
887 client_loop(int have_pty
, int escape_char_arg
, int ssh2_chan_id
)
889 fd_set
*readset
= NULL
, *writeset
= NULL
;
890 double start_time
, total_time
;
891 int max_fd
= 0, max_fd2
= 0, len
, rekeying
= 0, nalloc
= 0;
894 debug("Entering interactive session.");
896 start_time
= get_current_time();
898 /* Initialize variables. */
903 buffer_high
= 64 * 1024;
904 connection_in
= packet_get_connection_in();
905 connection_out
= packet_get_connection_out();
906 max_fd
= MAX(connection_in
, connection_out
);
909 /* enable nonblocking unless tty */
910 if (!isatty(fileno(stdin
)))
911 set_nonblock(fileno(stdin
));
912 if (!isatty(fileno(stdout
)))
913 set_nonblock(fileno(stdout
));
914 if (!isatty(fileno(stderr
)))
915 set_nonblock(fileno(stderr
));
916 max_fd
= MAX(max_fd
, fileno(stdin
));
917 max_fd
= MAX(max_fd
, fileno(stdout
));
918 max_fd
= MAX(max_fd
, fileno(stderr
));
924 escape_char
= escape_char_arg
;
926 /* Initialize buffers. */
927 buffer_init(&stdin_buffer
);
928 buffer_init(&stdout_buffer
);
929 buffer_init(&stderr_buffer
);
931 client_init_dispatch();
934 * Set signal handlers, (e.g. to restore non-blocking mode)
935 * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
937 if (signal(SIGINT
, SIG_IGN
) != SIG_IGN
)
938 signal(SIGINT
, signal_handler
);
939 if (signal(SIGQUIT
, SIG_IGN
) != SIG_IGN
)
940 signal(SIGQUIT
, signal_handler
);
941 if (signal(SIGTERM
, SIG_IGN
) != SIG_IGN
)
942 signal(SIGTERM
, signal_handler
);
944 signal(SIGWINCH
, window_change_handler
);
950 session_ident
= ssh2_chan_id
;
951 if (escape_char
!= SSH_ESCAPECHAR_NONE
)
952 channel_register_filter(session_ident
,
953 simple_escape_filter
);
954 if (session_ident
!= -1)
955 channel_register_cleanup(session_ident
,
956 client_channel_closed
);
958 /* Check if we should immediately send eof on stdin. */
959 client_check_initial_eof_on_stdin();
962 /* Main loop of the client for the interactive session mode. */
963 while (!quit_pending
) {
965 /* Process buffered packets sent by the server. */
966 client_process_buffered_input_packets();
968 if (compat20
&& session_closed
&& !channel_still_open())
971 rekeying
= (xxx_kex
!= NULL
&& !xxx_kex
->done
);
974 debug("rekeying in progress");
977 * Make packets of buffered stdin data, and buffer
978 * them for sending to the server.
981 client_make_packets_from_stdin_data();
984 * Make packets from buffered channel data, and
985 * enqueue them for sending to the server.
987 if (packet_not_very_much_data_to_write())
988 channel_output_poll();
991 * Check if the window size has changed, and buffer a
992 * message about it to the server if so.
994 client_check_window_change();
1000 * Wait until we have something to do (something becomes
1001 * available on one of the descriptors).
1004 client_wait_until_can_do_something(&readset
, &writeset
,
1005 &max_fd2
, &nalloc
, rekeying
);
1010 /* Do channel operations unless rekeying in progress. */
1012 channel_after_select(readset
, writeset
);
1013 if (need_rekeying
|| packet_need_rekeying()) {
1014 debug("need rekeying");
1016 kex_send_kexinit(xxx_kex
);
1021 /* Buffer input from the connection. */
1022 client_process_net_input(readset
);
1028 /* Buffer data from stdin */
1029 client_process_input(readset
);
1031 * Process output to stdout and stderr. Output to
1032 * the connection is processed elsewhere (above).
1034 client_process_output(writeset
);
1037 /* Send as much buffered packet data as possible to the sender. */
1038 if (FD_ISSET(connection_out
, writeset
))
1039 packet_write_poll();
1046 /* Terminate the session. */
1048 /* Stop watching for window change. */
1050 signal(SIGWINCH
, SIG_DFL
);
1057 /* restore blocking io */
1058 if (!isatty(fileno(stdin
)))
1059 unset_nonblock(fileno(stdin
));
1060 if (!isatty(fileno(stdout
)))
1061 unset_nonblock(fileno(stdout
));
1062 if (!isatty(fileno(stderr
)))
1063 unset_nonblock(fileno(stderr
));
1066 * If there was no shell or command requested, there will be no remote
1067 * exit status to be returned. In that case, clear error code if the
1068 * connection was deliberately terminated at this end.
1070 if (no_shell_flag
&& received_signal
== SIGTERM
) {
1071 received_signal
= 0;
1075 if (received_signal
)
1076 fatal("Killed by signal %d.", (int) received_signal
);
1079 * In interactive mode (with pseudo tty) display a message indicating
1080 * that the connection has been closed.
1082 if (have_pty
&& options
.log_level
!= SYSLOG_LEVEL_QUIET
) {
1083 snprintf(buf
, sizeof buf
, "Connection to %.64s closed.\r\n", host
);
1084 buffer_append(&stderr_buffer
, buf
, strlen(buf
));
1087 /* Output any buffered data for stdout. */
1088 while (buffer_len(&stdout_buffer
) > 0) {
1089 len
= write(fileno(stdout
), buffer_ptr(&stdout_buffer
),
1090 buffer_len(&stdout_buffer
));
1092 error("Write failed flushing stdout buffer.");
1095 buffer_consume(&stdout_buffer
, len
);
1096 stdout_bytes
+= len
;
1099 /* Output any buffered data for stderr. */
1100 while (buffer_len(&stderr_buffer
) > 0) {
1101 len
= write(fileno(stderr
), buffer_ptr(&stderr_buffer
),
1102 buffer_len(&stderr_buffer
));
1104 error("Write failed flushing stderr buffer.");
1107 buffer_consume(&stderr_buffer
, len
);
1108 stderr_bytes
+= len
;
1111 /* Clear and free any buffers. */
1112 memset(buf
, 0, sizeof(buf
));
1113 buffer_free(&stdin_buffer
);
1114 buffer_free(&stdout_buffer
);
1115 buffer_free(&stderr_buffer
);
1117 /* Report bytes transferred, and transfer rates. */
1118 total_time
= get_current_time() - start_time
;
1119 debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
1120 stdin_bytes
, stdout_bytes
, stderr_bytes
, total_time
);
1122 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
1123 stdin_bytes
/ total_time
, stdout_bytes
/ total_time
,
1124 stderr_bytes
/ total_time
);
1126 /* Return the exit status of the program. */
1127 debug("Exit status %d", exit_status
);
1134 client_input_stdout_data(int type
, u_int32_t seq
, void *ctxt
)
1137 char *data
= packet_get_string(&data_len
);
1139 buffer_append(&stdout_buffer
, data
, data_len
);
1140 memset(data
, 0, data_len
);
1144 client_input_stderr_data(int type
, u_int32_t seq
, void *ctxt
)
1147 char *data
= packet_get_string(&data_len
);
1149 buffer_append(&stderr_buffer
, data
, data_len
);
1150 memset(data
, 0, data_len
);
1154 client_input_exit_status(int type
, u_int32_t seq
, void *ctxt
)
1156 exit_status
= packet_get_int();
1158 /* Acknowledge the exit. */
1159 packet_start(SSH_CMSG_EXIT_CONFIRMATION
);
1162 * Must wait for packet to be sent since we are
1165 packet_write_wait();
1166 /* Flag that we want to exit. */
1170 client_input_agent_open(int type
, u_int32_t seq
, void *ctxt
)
1173 int remote_id
, sock
;
1175 /* Read the remote channel number from the message. */
1176 remote_id
= packet_get_int();
1180 * Get a connection to the local authentication agent (this may again
1183 sock
= ssh_get_authentication_socket();
1186 * If we could not connect the agent, send an error message back to
1187 * the server. This should never happen unless the agent dies,
1188 * because authentication forwarding is only enabled if we have an
1192 c
= channel_new("", SSH_CHANNEL_OPEN
, sock
, sock
,
1193 -1, 0, 0, 0, "authentication agent connection", 1);
1194 c
->remote_id
= remote_id
;
1198 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE
);
1199 packet_put_int(remote_id
);
1201 /* Send a confirmation to the remote host. */
1202 debug("Forwarding authentication connection.");
1203 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION
);
1204 packet_put_int(remote_id
);
1205 packet_put_int(c
->self
);
1211 client_request_forwarded_tcpip(const char *request_type
, int rchan
)
1214 char *listen_address
, *originator_address
;
1215 int listen_port
, originator_port
;
1218 /* Get rest of the packet */
1219 listen_address
= packet_get_string(NULL
);
1220 listen_port
= packet_get_int();
1221 originator_address
= packet_get_string(NULL
);
1222 originator_port
= packet_get_int();
1225 debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
1226 listen_address
, listen_port
, originator_address
, originator_port
);
1228 sock
= channel_connect_by_listen_address(listen_port
);
1230 xfree(originator_address
);
1231 xfree(listen_address
);
1234 c
= channel_new("forwarded-tcpip",
1235 SSH_CHANNEL_CONNECTING
, sock
, sock
, -1,
1236 CHAN_TCP_WINDOW_DEFAULT
, CHAN_TCP_WINDOW_DEFAULT
, 0,
1237 originator_address
, 1);
1238 xfree(originator_address
);
1239 xfree(listen_address
);
1244 client_request_x11(const char *request_type
, int rchan
)
1248 int originator_port
;
1251 if (!options
.forward_x11
) {
1252 error("Warning: ssh server tried X11 forwarding.");
1253 error("Warning: this is probably a break in attempt by a malicious server.");
1256 originator
= packet_get_string(NULL
);
1257 if (datafellows
& SSH_BUG_X11FWD
) {
1258 debug2("buggy server: x11 request w/o originator_port");
1259 originator_port
= 0;
1261 originator_port
= packet_get_int();
1264 /* XXX check permission */
1265 debug("client_request_x11: request from %s %d", originator
,
1268 sock
= x11_connect_display();
1271 c
= channel_new("x11",
1272 SSH_CHANNEL_X11_OPEN
, sock
, sock
, -1,
1273 CHAN_TCP_WINDOW_DEFAULT
, CHAN_X11_PACKET_DEFAULT
, 0, "x11", 1);
1279 client_request_agent(const char *request_type
, int rchan
)
1284 if (!options
.forward_agent
) {
1285 error("Warning: ssh server tried agent forwarding.");
1286 error("Warning: this is probably a break in attempt by a malicious server.");
1289 sock
= ssh_get_authentication_socket();
1292 c
= channel_new("authentication agent connection",
1293 SSH_CHANNEL_OPEN
, sock
, sock
, -1,
1294 CHAN_X11_WINDOW_DEFAULT
, CHAN_TCP_WINDOW_DEFAULT
, 0,
1295 "authentication agent connection", 1);
1300 /* XXXX move to generic input handler */
1302 client_input_channel_open(int type
, u_int32_t seq
, void *ctxt
)
1307 u_int rmaxpack
, rwindow
, len
;
1309 ctype
= packet_get_string(&len
);
1310 rchan
= packet_get_int();
1311 rwindow
= packet_get_int();
1312 rmaxpack
= packet_get_int();
1314 debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1315 ctype
, rchan
, rwindow
, rmaxpack
);
1317 if (strcmp(ctype
, "forwarded-tcpip") == 0) {
1318 c
= client_request_forwarded_tcpip(ctype
, rchan
);
1319 } else if (strcmp(ctype
, "x11") == 0) {
1320 c
= client_request_x11(ctype
, rchan
);
1321 } else if (strcmp(ctype
, "auth-agent@openssh.com") == 0) {
1322 c
= client_request_agent(ctype
, rchan
);
1324 /* XXX duplicate : */
1326 debug("confirm %s", ctype
);
1327 c
->remote_id
= rchan
;
1328 c
->remote_window
= rwindow
;
1329 c
->remote_maxpacket
= rmaxpack
;
1330 if (c
->type
!= SSH_CHANNEL_CONNECTING
) {
1331 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION
);
1332 packet_put_int(c
->remote_id
);
1333 packet_put_int(c
->self
);
1334 packet_put_int(c
->local_window
);
1335 packet_put_int(c
->local_maxpacket
);
1339 debug("failure %s", ctype
);
1340 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE
);
1341 packet_put_int(rchan
);
1342 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED
);
1343 if (!(datafellows
& SSH_BUG_OPENFAILURE
)) {
1344 packet_put_cstring("open failed");
1345 packet_put_cstring("");
1352 client_input_channel_req(int type
, u_int32_t seq
, void *ctxt
)
1355 int id
, reply
, success
= 0;
1358 id
= packet_get_int();
1359 rtype
= packet_get_string(NULL
);
1360 reply
= packet_get_char();
1362 debug("client_input_channel_req: channel %d rtype %s reply %d",
1365 if (session_ident
== -1) {
1366 error("client_input_channel_req: no channel %d", session_ident
);
1367 } else if (id
!= session_ident
) {
1368 error("client_input_channel_req: channel %d: wrong channel: %d",
1371 c
= channel_lookup(id
);
1373 error("client_input_channel_req: channel %d: unknown channel", id
);
1374 } else if (strcmp(rtype
, "exit-status") == 0) {
1376 exit_status
= packet_get_int();
1380 packet_start(success
?
1381 SSH2_MSG_CHANNEL_SUCCESS
: SSH2_MSG_CHANNEL_FAILURE
);
1382 packet_put_int(c
->remote_id
);
1388 client_input_global_request(int type
, u_int32_t seq
, void *ctxt
)
1394 rtype
= packet_get_string(NULL
);
1395 want_reply
= packet_get_char();
1396 debug("client_input_global_request: rtype %s want_reply %d",
1399 packet_start(success
?
1400 SSH2_MSG_REQUEST_SUCCESS
: SSH2_MSG_REQUEST_FAILURE
);
1402 packet_write_wait();
1408 client_init_dispatch_20(void)
1410 dispatch_init(&dispatch_protocol_error
);
1412 dispatch_set(SSH2_MSG_CHANNEL_CLOSE
, &channel_input_oclose
);
1413 dispatch_set(SSH2_MSG_CHANNEL_DATA
, &channel_input_data
);
1414 dispatch_set(SSH2_MSG_CHANNEL_EOF
, &channel_input_ieof
);
1415 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA
, &channel_input_extended_data
);
1416 dispatch_set(SSH2_MSG_CHANNEL_OPEN
, &client_input_channel_open
);
1417 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION
, &channel_input_open_confirmation
);
1418 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE
, &channel_input_open_failure
);
1419 dispatch_set(SSH2_MSG_CHANNEL_REQUEST
, &client_input_channel_req
);
1420 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST
, &channel_input_window_adjust
);
1421 dispatch_set(SSH2_MSG_GLOBAL_REQUEST
, &client_input_global_request
);
1424 dispatch_set(SSH2_MSG_KEXINIT
, &kex_input_kexinit
);
1426 /* global request reply messages */
1427 dispatch_set(SSH2_MSG_REQUEST_FAILURE
, &client_global_request_reply
);
1428 dispatch_set(SSH2_MSG_REQUEST_SUCCESS
, &client_global_request_reply
);
1431 client_init_dispatch_13(void)
1433 dispatch_init(NULL
);
1434 dispatch_set(SSH_MSG_CHANNEL_CLOSE
, &channel_input_close
);
1435 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION
, &channel_input_close_confirmation
);
1436 dispatch_set(SSH_MSG_CHANNEL_DATA
, &channel_input_data
);
1437 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION
, &channel_input_open_confirmation
);
1438 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE
, &channel_input_open_failure
);
1439 dispatch_set(SSH_MSG_PORT_OPEN
, &channel_input_port_open
);
1440 dispatch_set(SSH_SMSG_EXITSTATUS
, &client_input_exit_status
);
1441 dispatch_set(SSH_SMSG_STDERR_DATA
, &client_input_stderr_data
);
1442 dispatch_set(SSH_SMSG_STDOUT_DATA
, &client_input_stdout_data
);
1444 dispatch_set(SSH_SMSG_AGENT_OPEN
, options
.forward_agent
?
1445 &client_input_agent_open
: &deny_input_open
);
1446 dispatch_set(SSH_SMSG_X11_OPEN
, options
.forward_x11
?
1447 &x11_input_open
: &deny_input_open
);
1450 client_init_dispatch_15(void)
1452 client_init_dispatch_13();
1453 dispatch_set(SSH_MSG_CHANNEL_CLOSE
, &channel_input_ieof
);
1454 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION
, & channel_input_oclose
);
1457 client_init_dispatch(void)
1460 client_init_dispatch_20();
1462 client_init_dispatch_13();
1464 client_init_dispatch_15();
1467 /* client specific fatal cleanup */
1472 leave_non_blocking();