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 1.133 2004/10/29 22:53:56 djm Exp $");
79 #include "clientloop.h"
84 #include "monitor_fdpass.h"
89 extern Options options;
91 /* Flag indicating that stdin should be redirected from /dev/null. */
92 extern int stdin_null_flag;
94 /* Flag indicating that no shell has been requested */
95 extern int no_shell_flag;
98 extern int control_fd;
101 * Name of the host we are connecting to. This is the name given on the
102 * command line, or the HostName specified for the user-supplied name in a
103 * configuration file.
108 * Flag to indicate that we have received a window change signal which has
109 * not yet been processed. This will cause a message indicating the new
110 * window size to be sent to the server a little later. This is volatile
111 * because this is updated in a signal handler.
113 static volatile sig_atomic_t received_window_change_signal = 0;
114 static volatile sig_atomic_t received_signal = 0;
116 /* Flag indicating whether the user\'s terminal is in non-blocking mode. */
117 static int in_non_blocking_mode = 0;
119 /* Common data for the client loop code. */
120 static int quit_pending; /* Set to non-zero to quit the client loop. */
121 static int escape_char; /* Escape character. */
122 static int escape_pending; /* Last character was the escape character */
123 static int last_was_cr; /* Last character was a newline. */
124 static int exit_status; /* Used to store the exit status of the command. */
125 static int stdin_eof; /* EOF has been encountered on standard error. */
126 static Buffer stdin_buffer; /* Buffer for stdin data. */
127 static Buffer stdout_buffer; /* Buffer for stdout data. */
128 static Buffer stderr_buffer; /* Buffer for stderr data. */
129 static u_long stdin_bytes, stdout_bytes, stderr_bytes;
130 static u_int buffer_high;/* Soft max buffer size. */
131 static int connection_in; /* Connection to server (input). */
132 static int connection_out; /* Connection to server (output). */
133 static int need_rekeying; /* Set to non-zero if rekeying is requested. */
134 static int session_closed = 0; /* In SSH2: login session closed. */
135 static int server_alive_timeouts = 0;
137 static void client_init_dispatch(void);
138 int session_ident = -1;
152 void ssh_process_session2_setup(int, int, int, Buffer *);
154 /* Restores stdin to blocking mode. */
157 leave_non_blocking(void)
159 if (in_non_blocking_mode) {
160 unset_nonblock(fileno(stdin));
161 in_non_blocking_mode = 0;
165 /* Puts stdin terminal in non-blocking mode. */
168 enter_non_blocking(void)
170 in_non_blocking_mode = 1;
171 set_nonblock(fileno(stdin));
175 * Signal handler for the window change signal (SIGWINCH). This just sets a
176 * flag indicating that the window has changed.
180 window_change_handler(int sig)
182 received_window_change_signal = 1;
183 signal(SIGWINCH, window_change_handler);
187 * Signal handler for signals that cause the program to terminate. These
188 * signals must be trapped to restore terminal modes.
192 signal_handler(int sig)
194 received_signal = sig;
199 * Returns current time in seconds from Jan 1, 1970 with the maximum
200 * available resolution.
204 get_current_time(void)
207 gettimeofday(&tv, NULL);
208 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
212 * This is called when the interactive is entered. This checks if there is
213 * an EOF coming on stdin. We must check this explicitly, as select() does
214 * not appear to wake up when redirecting from /dev/null.
218 client_check_initial_eof_on_stdin(void)
224 * If standard input is to be "redirected from /dev/null", we simply
225 * mark that we have seen an EOF and send an EOF message to the
226 * server. Otherwise, we try to read a single character; it appears
227 * that for some files, such /dev/null, select() never wakes up for
228 * read for this descriptor, which means that we never get EOF. This
229 * way we will get the EOF if stdin comes from /dev/null or similar.
231 if (stdin_null_flag) {
232 /* Fake EOF on stdin. */
233 debug("Sending eof.");
235 packet_start(SSH_CMSG_EOF);
238 enter_non_blocking();
240 /* Check for immediate EOF on stdin. */
241 len = read(fileno(stdin), buf, 1);
243 /* EOF. Record that we have seen it and send EOF to server. */
244 debug("Sending eof.");
246 packet_start(SSH_CMSG_EOF);
248 } else if (len > 0) {
250 * Got data. We must store the data in the buffer,
251 * and also process it as an escape character if
254 if ((u_char) buf[0] == escape_char)
257 buffer_append(&stdin_buffer, buf, 1);
259 leave_non_blocking();
265 * Make packets from buffered stdin data, and buffer them for sending to the
270 client_make_packets_from_stdin_data(void)
274 /* Send buffered stdin data to the server. */
275 while (buffer_len(&stdin_buffer) > 0 &&
276 packet_not_very_much_data_to_write()) {
277 len = buffer_len(&stdin_buffer);
278 /* Keep the packets at reasonable size. */
279 if (len > packet_get_maxsize())
280 len = packet_get_maxsize();
281 packet_start(SSH_CMSG_STDIN_DATA);
282 packet_put_string(buffer_ptr(&stdin_buffer), len);
284 buffer_consume(&stdin_buffer, len);
286 /* If we have a pending EOF, send it now. */
287 if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
288 packet_start(SSH_CMSG_EOF);
295 * Checks if the client window has changed, and sends a packet about it to
296 * the server if so. The actual change is detected elsewhere (by a software
297 * interrupt on Unix); this just checks the flag and sends a message if
302 client_check_window_change(void)
306 if (! received_window_change_signal)
309 received_window_change_signal = 0;
311 debug2("client_check_window_change: changed");
314 channel_send_window_changes();
316 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
318 packet_start(SSH_CMSG_WINDOW_SIZE);
319 packet_put_int(ws.ws_row);
320 packet_put_int(ws.ws_col);
321 packet_put_int(ws.ws_xpixel);
322 packet_put_int(ws.ws_ypixel);
328 client_global_request_reply(int type, u_int32_t seq, void *ctxt)
330 server_alive_timeouts = 0;
331 client_global_request_reply_fwd(type, seq, ctxt);
335 server_alive_check(void)
337 if (++server_alive_timeouts > options.server_alive_count_max)
338 packet_disconnect("Timeout, server not responding.");
339 packet_start(SSH2_MSG_GLOBAL_REQUEST);
340 packet_put_cstring("keepalive@openssh.com");
341 packet_put_char(1); /* boolean: want reply */
346 * Waits until the client can do something (some data becomes available on
347 * one of the file descriptors).
350 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
351 int *maxfdp, u_int *nallocp, int rekeying)
353 struct timeval tv, *tvp;
356 /* Add any selections by the channel mechanism. */
357 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying);
360 /* Read from the connection, unless our buffers are full. */
361 if (buffer_len(&stdout_buffer) < buffer_high &&
362 buffer_len(&stderr_buffer) < buffer_high &&
363 channel_not_very_much_buffered_data())
364 FD_SET(connection_in, *readsetp);
366 * Read from stdin, unless we have seen EOF or have very much
367 * buffered data to send to the server.
369 if (!stdin_eof && packet_not_very_much_data_to_write())
370 FD_SET(fileno(stdin), *readsetp);
372 /* Select stdout/stderr if have data in buffer. */
373 if (buffer_len(&stdout_buffer) > 0)
374 FD_SET(fileno(stdout), *writesetp);
375 if (buffer_len(&stderr_buffer) > 0)
376 FD_SET(fileno(stderr), *writesetp);
378 /* channel_prepare_select could have closed the last channel */
379 if (session_closed && !channel_still_open() &&
380 !packet_have_data_to_write()) {
381 /* clear mask since we did not call select() */
382 memset(*readsetp, 0, *nallocp);
383 memset(*writesetp, 0, *nallocp);
386 FD_SET(connection_in, *readsetp);
390 /* Select server connection if have data to write to the server. */
391 if (packet_have_data_to_write())
392 FD_SET(connection_out, *writesetp);
394 if (control_fd != -1)
395 FD_SET(control_fd, *readsetp);
398 * Wait for something to happen. This will suspend the process until
399 * some selected descriptor can be read, written, or has some other
403 if (options.server_alive_interval == 0 || !compat20)
406 tv.tv_sec = options.server_alive_interval;
410 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
415 * We have to clear the select masks, because we return.
416 * We have to return, because the mainloop checks for the flags
417 * set by the signal handlers.
419 memset(*readsetp, 0, *nallocp);
420 memset(*writesetp, 0, *nallocp);
424 /* Note: we might still have data in the buffers. */
425 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
426 buffer_append(&stderr_buffer, buf, strlen(buf));
429 server_alive_check();
433 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
435 /* Flush stdout and stderr buffers. */
436 if (buffer_len(bout) > 0)
437 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout));
438 if (buffer_len(berr) > 0)
439 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr));
444 * Free (and clear) the buffer to reduce the amount of data that gets
451 /* Send the suspend signal to the program itself. */
452 kill(getpid(), SIGTSTP);
454 /* Reset window sizes in case they have changed */
455 received_window_change_signal = 1;
457 /* OK, we have been continued by the user. Reinitialize buffers. */
466 client_process_net_input(fd_set * readset)
472 * Read input from the server, and add any such data to the buffer of
473 * the packet subsystem.
475 if (FD_ISSET(connection_in, readset)) {
476 /* Read as much as possible. */
477 len = read(connection_in, buf, sizeof(buf));
479 /* Received EOF. The remote host has closed the connection. */
480 snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n",
482 buffer_append(&stderr_buffer, buf, strlen(buf));
487 * There is a kernel bug on Solaris that causes select to
488 * sometimes wake up even though there is no data available.
490 if (len < 0 && (errno == EAGAIN || errno == EINTR))
494 /* An error has encountered. Perhaps there is a network problem. */
495 snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n",
496 host, strerror(errno));
497 buffer_append(&stderr_buffer, buf, strlen(buf));
501 packet_process_incoming(buf, len);
506 client_subsystem_reply(int type, u_int32_t seq, void *ctxt)
511 id = packet_get_int();
514 if ((c = channel_lookup(id)) == NULL) {
515 error("%s: no channel for id %d", __func__, id);
519 if (type == SSH2_MSG_CHANNEL_SUCCESS)
520 debug2("Request suceeded on channel %d", id);
521 else if (type == SSH2_MSG_CHANNEL_FAILURE) {
522 error("Request failed on channel %d", id);
528 client_extra_session2_setup(int id, void *arg)
530 struct confirm_ctx *cctx = arg;
535 fatal("%s: cctx == NULL", __func__);
536 if ((c = channel_lookup(id)) == NULL)
537 fatal("%s: no channel for id %d", __func__, id);
539 client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
540 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env,
541 client_subsystem_reply);
543 c->confirm_ctx = NULL;
544 buffer_free(&cctx->cmd);
546 if (cctx->env != NULL) {
547 for (i = 0; cctx->env[i] != NULL; i++)
555 client_process_control(fd_set * readset)
559 int client_fd, new_fd[3], ver, i, allowed;
561 struct sockaddr_storage addr;
562 struct confirm_ctx *cctx;
569 * Accept connection on control socket
571 if (control_fd == -1 || !FD_ISSET(control_fd, readset))
574 memset(&addr, 0, sizeof(addr));
575 addrlen = sizeof(addr);
576 if ((client_fd = accept(control_fd,
577 (struct sockaddr*)&addr, &addrlen)) == -1) {
578 error("%s accept: %s", __func__, strerror(errno));
582 if (getpeereid(client_fd, &euid, &egid) < 0) {
583 error("%s getpeereid failed: %s", __func__, strerror(errno));
587 if ((euid != 0) && (getuid() != euid)) {
588 error("control mode uid mismatch: peer euid %u != uid %u",
589 (u_int) euid, (u_int) getuid());
595 if (options.control_master == 2)
596 allowed = ask_permission("Allow shared connection to %s? ",
599 unset_nonblock(client_fd);
603 buffer_put_int(&m, allowed);
604 buffer_put_int(&m, getpid());
605 if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
606 error("%s: client msg_send failed", __func__);
614 error("Refused control connection");
620 if (ssh_msg_recv(client_fd, &m) == -1) {
621 error("%s: client msg_recv failed", __func__);
627 if ((ver = buffer_get_char(&m)) != 0) {
628 error("%s: wrong client version %d", __func__, ver);
634 cctx = xmalloc(sizeof(*cctx));
635 memset(cctx, 0, sizeof(*cctx));
637 cctx->want_tty = buffer_get_int(&m);
638 cctx->want_subsys = buffer_get_int(&m);
639 cctx->term = buffer_get_string(&m, &len);
641 cmd = buffer_get_string(&m, &len);
642 buffer_init(&cctx->cmd);
643 buffer_append(&cctx->cmd, cmd, strlen(cmd));
645 env_len = buffer_get_int(&m);
646 env_len = MIN(env_len, 4096);
647 debug3("%s: receiving %d env vars", __func__, env_len);
649 cctx->env = xmalloc(sizeof(*cctx->env) * (env_len + 1));
650 for (i = 0; i < env_len; i++)
651 cctx->env[i] = buffer_get_string(&m, &len);
655 debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__,
656 cctx->want_tty, cctx->want_subsys, cmd);
658 /* Gather fds from client */
659 new_fd[0] = mm_receive_fd(client_fd);
660 new_fd[1] = mm_receive_fd(client_fd);
661 new_fd[2] = mm_receive_fd(client_fd);
663 debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
664 new_fd[0], new_fd[1], new_fd[2]);
666 /* Try to pick up ttymodes from client before it goes raw */
667 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
668 error("%s: tcgetattr: %s", __func__, strerror(errno));
671 if (ssh_msg_send(client_fd, /* version */0, &m) == -1) {
672 error("%s: client msg_send failed", __func__);
682 /* enable nonblocking unless tty */
683 if (!isatty(new_fd[0]))
684 set_nonblock(new_fd[0]);
685 if (!isatty(new_fd[1]))
686 set_nonblock(new_fd[1]);
687 if (!isatty(new_fd[2]))
688 set_nonblock(new_fd[2]);
690 set_nonblock(client_fd);
692 c = channel_new("session", SSH_CHANNEL_OPENING,
693 new_fd[0], new_fd[1], new_fd[2],
694 CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT,
695 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
698 c->ctl_fd = client_fd;
700 debug3("%s: channel_new: %d", __func__, c->self);
702 channel_send_open(c->self);
703 channel_register_confirm(c->self, client_extra_session2_setup, cctx);
707 process_cmdline(void)
709 void (*handler)(int);
711 u_short fwd_port, fwd_host_port;
712 char buf[1024], sfwd_port[6], sfwd_host_port[6];
717 handler = signal(SIGINT, SIG_IGN);
718 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
721 while (*s && isspace(*s))
724 s++; /* Skip cmdline '-', if any */
728 if (*s == 'h' || *s == 'H' || *s == '?') {
730 logit(" -Lport:host:hostport Request local forward");
731 logit(" -Rport:host:hostport Request remote forward");
732 logit(" -KRhostport Cancel remote forward");
740 if (*s != 'L' && *s != 'R') {
741 logit("Invalid command.");
746 if (local && delete) {
747 logit("Not supported.");
750 if ((!local || delete) && !compat20) {
751 logit("Not supported for SSH protocol version 1.");
756 while (*s && isspace(*s))
760 if (sscanf(s, "%5[0-9]", sfwd_host_port) != 1) {
761 logit("Bad forwarding specification.");
764 if ((fwd_host_port = a2port(sfwd_host_port)) == 0) {
765 logit("Bad forwarding port(s).");
768 channel_request_rforward_cancel(fwd_host_port);
770 if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]",
771 sfwd_port, buf, sfwd_host_port) != 3 &&
772 sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]",
773 sfwd_port, buf, sfwd_host_port) != 3) {
774 logit("Bad forwarding specification.");
777 if ((fwd_port = a2port(sfwd_port)) == 0 ||
778 (fwd_host_port = a2port(sfwd_host_port)) == 0) {
779 logit("Bad forwarding port(s).");
783 if (channel_setup_local_fwd_listener(fwd_port, buf,
784 fwd_host_port, options.gateway_ports) < 0) {
785 logit("Port forwarding failed.");
789 channel_request_remote_forwarding(fwd_port, buf,
791 logit("Forwarding port.");
795 signal(SIGINT, handler);
801 /* process the characters one by one */
803 process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
812 for (i = 0; i < len; i++) {
813 /* Get one character at a time. */
816 if (escape_pending) {
817 /* We have previously seen an escape character. */
818 /* Clear the flag now. */
821 /* Process the escaped character. */
824 /* Terminate the connection. */
825 snprintf(string, sizeof string, "%c.\r\n", escape_char);
826 buffer_append(berr, string, strlen(string));
832 /* Suspend the program. */
833 /* Print a message to that effect to the user. */
834 snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char);
835 buffer_append(berr, string, strlen(string));
837 /* Restore terminal modes and suspend. */
838 client_suspend_self(bin, bout, berr);
840 /* We have been continued. */
845 snprintf(string, sizeof string,
846 "%cB\r\n", escape_char);
847 buffer_append(berr, string,
849 channel_request_start(session_ident,
851 packet_put_int(1000);
858 if (datafellows & SSH_BUG_NOREKEY)
859 logit("Server does not support re-keying");
867 * Detach the program (continue to serve connections,
868 * but put in background and no more new connections).
870 /* Restore tty modes. */
873 /* Stop listening for new connections. */
874 channel_stop_listening();
876 snprintf(string, sizeof string,
877 "%c& [backgrounded]\n", escape_char);
878 buffer_append(berr, string, strlen(string));
880 /* Fork into background. */
883 error("fork: %.100s", strerror(errno));
886 if (pid != 0) { /* This is the parent. */
887 /* The parent just exits. */
890 /* The child continues serving connections. */
892 buffer_append(bin, "\004", 1);
893 /* fake EOF on stdin */
895 } else if (!stdin_eof) {
897 * Sending SSH_CMSG_EOF alone does not always appear
898 * to be enough. So we try to send an EOF character
901 packet_start(SSH_CMSG_STDIN_DATA);
902 packet_put_string("\004", 1);
906 if (buffer_len(bin) == 0) {
907 packet_start(SSH_CMSG_EOF);
914 snprintf(string, sizeof string,
916 Supported escape sequences:\r\n\
917 %c. - terminate connection\r\n\
918 %cB - send a BREAK to the remote system\r\n\
919 %cC - open a command line\r\n\
920 %cR - Request rekey (SSH protocol 2 only)\r\n\
921 %c^Z - suspend ssh\r\n\
922 %c# - list forwarded connections\r\n\
923 %c& - background ssh (when waiting for connections to terminate)\r\n\
924 %c? - this message\r\n\
925 %c%c - send the escape character by typing it twice\r\n\
926 (Note that escapes are only recognized immediately after newline.)\r\n",
927 escape_char, escape_char, escape_char, escape_char,
928 escape_char, escape_char, escape_char, escape_char,
929 escape_char, escape_char, escape_char);
930 buffer_append(berr, string, strlen(string));
934 snprintf(string, sizeof string, "%c#\r\n", escape_char);
935 buffer_append(berr, string, strlen(string));
936 s = channel_open_message();
937 buffer_append(berr, s, strlen(s));
946 if (ch != escape_char) {
947 buffer_put_char(bin, escape_char);
950 /* Escaped characters fall through here */
955 * The previous character was not an escape char. Check if this
958 if (last_was_cr && ch == escape_char) {
959 /* It is. Set the flag and continue to next character. */
966 * Normal character. Record whether it was a newline,
967 * and append it to the buffer.
969 last_was_cr = (ch == '\r' || ch == '\n');
970 buffer_put_char(bin, ch);
977 client_process_input(fd_set * readset)
982 /* Read input from stdin. */
983 if (FD_ISSET(fileno(stdin), readset)) {
984 /* Read as much as possible. */
985 len = read(fileno(stdin), buf, sizeof(buf));
986 if (len < 0 && (errno == EAGAIN || errno == EINTR))
987 return; /* we'll try again later */
990 * Received EOF or error. They are treated
991 * similarly, except that an error message is printed
992 * if it was an error condition.
995 snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno));
996 buffer_append(&stderr_buffer, buf, strlen(buf));
998 /* Mark that we have seen EOF. */
1001 * Send an EOF message to the server unless there is
1002 * data in the buffer. If there is data in the
1003 * buffer, no message will be sent now. Code
1004 * elsewhere will send the EOF when the buffer
1005 * becomes empty if stdin_eof is set.
1007 if (buffer_len(&stdin_buffer) == 0) {
1008 packet_start(SSH_CMSG_EOF);
1011 } else if (escape_char == SSH_ESCAPECHAR_NONE) {
1013 * Normal successful read, and no escape character.
1014 * Just append the data to buffer.
1016 buffer_append(&stdin_buffer, buf, len);
1019 * Normal, successful read. But we have an escape character
1020 * and have to process the characters one by one.
1022 if (process_escapes(&stdin_buffer, &stdout_buffer,
1023 &stderr_buffer, buf, len) == -1)
1030 client_process_output(fd_set * writeset)
1035 /* Write buffered output to stdout. */
1036 if (FD_ISSET(fileno(stdout), writeset)) {
1037 /* Write as much data as possible. */
1038 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1039 buffer_len(&stdout_buffer));
1041 if (errno == EINTR || errno == EAGAIN)
1045 * An error or EOF was encountered. Put an
1046 * error message to stderr buffer.
1048 snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno));
1049 buffer_append(&stderr_buffer, buf, strlen(buf));
1054 /* Consume printed data from the buffer. */
1055 buffer_consume(&stdout_buffer, len);
1056 stdout_bytes += len;
1058 /* Write buffered output to stderr. */
1059 if (FD_ISSET(fileno(stderr), writeset)) {
1060 /* Write as much data as possible. */
1061 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1062 buffer_len(&stderr_buffer));
1064 if (errno == EINTR || errno == EAGAIN)
1067 /* EOF or error, but can't even print error message. */
1072 /* Consume printed characters from the buffer. */
1073 buffer_consume(&stderr_buffer, len);
1074 stderr_bytes += len;
1079 * Get packets from the connection input buffer, and process them as long as
1080 * there are packets available.
1082 * Any unknown packets received during the actual
1083 * session cause the session to terminate. This is
1084 * intended to make debugging easier since no
1085 * confirmations are sent. Any compatible protocol
1086 * extensions must be negotiated during the
1087 * preparatory phase.
1091 client_process_buffered_input_packets(void)
1093 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL);
1096 /* scan buf[] for '~' before sending data to the peer */
1099 simple_escape_filter(Channel *c, char *buf, int len)
1101 /* XXX we assume c->extended is writeable */
1102 return process_escapes(&c->input, &c->output, &c->extended, buf, len);
1106 client_channel_closed(int id, void *arg)
1108 channel_cancel_cleanup(id);
1114 * Implements the interactive session with the server. This is called after
1115 * the user has been authenticated, and a command has been started on the
1116 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1117 * used as an escape character for terminating or suspending the session.
1121 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1123 fd_set *readset = NULL, *writeset = NULL;
1124 double start_time, total_time;
1125 int max_fd = 0, max_fd2 = 0, len, rekeying = 0;
1129 debug("Entering interactive session.");
1131 start_time = get_current_time();
1133 /* Initialize variables. */
1138 buffer_high = 64 * 1024;
1139 connection_in = packet_get_connection_in();
1140 connection_out = packet_get_connection_out();
1141 max_fd = MAX(connection_in, connection_out);
1142 if (control_fd != -1)
1143 max_fd = MAX(max_fd, control_fd);
1146 /* enable nonblocking unless tty */
1147 if (!isatty(fileno(stdin)))
1148 set_nonblock(fileno(stdin));
1149 if (!isatty(fileno(stdout)))
1150 set_nonblock(fileno(stdout));
1151 if (!isatty(fileno(stderr)))
1152 set_nonblock(fileno(stderr));
1153 max_fd = MAX(max_fd, fileno(stdin));
1154 max_fd = MAX(max_fd, fileno(stdout));
1155 max_fd = MAX(max_fd, fileno(stderr));
1161 escape_char = escape_char_arg;
1163 /* Initialize buffers. */
1164 buffer_init(&stdin_buffer);
1165 buffer_init(&stdout_buffer);
1166 buffer_init(&stderr_buffer);
1168 client_init_dispatch();
1171 * Set signal handlers, (e.g. to restore non-blocking mode)
1172 * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1174 if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
1175 signal(SIGHUP, signal_handler);
1176 if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1177 signal(SIGINT, signal_handler);
1178 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1179 signal(SIGQUIT, signal_handler);
1180 if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1181 signal(SIGTERM, signal_handler);
1182 signal(SIGWINCH, window_change_handler);
1188 session_ident = ssh2_chan_id;
1189 if (escape_char != SSH_ESCAPECHAR_NONE)
1190 channel_register_filter(session_ident,
1191 simple_escape_filter);
1192 if (session_ident != -1)
1193 channel_register_cleanup(session_ident,
1194 client_channel_closed);
1196 /* Check if we should immediately send eof on stdin. */
1197 client_check_initial_eof_on_stdin();
1200 /* Main loop of the client for the interactive session mode. */
1201 while (!quit_pending) {
1203 /* Process buffered packets sent by the server. */
1204 client_process_buffered_input_packets();
1206 if (compat20 && session_closed && !channel_still_open())
1209 rekeying = (xxx_kex != NULL && !xxx_kex->done);
1212 debug("rekeying in progress");
1215 * Make packets of buffered stdin data, and buffer
1216 * them for sending to the server.
1219 client_make_packets_from_stdin_data();
1222 * Make packets from buffered channel data, and
1223 * enqueue them for sending to the server.
1225 if (packet_not_very_much_data_to_write())
1226 channel_output_poll();
1229 * Check if the window size has changed, and buffer a
1230 * message about it to the server if so.
1232 client_check_window_change();
1238 * Wait until we have something to do (something becomes
1239 * available on one of the descriptors).
1242 client_wait_until_can_do_something(&readset, &writeset,
1243 &max_fd2, &nalloc, rekeying);
1248 /* Do channel operations unless rekeying in progress. */
1250 channel_after_select(readset, writeset);
1251 if (need_rekeying || packet_need_rekeying()) {
1252 debug("need rekeying");
1254 kex_send_kexinit(xxx_kex);
1259 /* Buffer input from the connection. */
1260 client_process_net_input(readset);
1262 /* Accept control connections. */
1263 client_process_control(readset);
1269 /* Buffer data from stdin */
1270 client_process_input(readset);
1272 * Process output to stdout and stderr. Output to
1273 * the connection is processed elsewhere (above).
1275 client_process_output(writeset);
1278 /* Send as much buffered packet data as possible to the sender. */
1279 if (FD_ISSET(connection_out, writeset))
1280 packet_write_poll();
1287 /* Terminate the session. */
1289 /* Stop watching for window change. */
1290 signal(SIGWINCH, SIG_DFL);
1297 /* restore blocking io */
1298 if (!isatty(fileno(stdin)))
1299 unset_nonblock(fileno(stdin));
1300 if (!isatty(fileno(stdout)))
1301 unset_nonblock(fileno(stdout));
1302 if (!isatty(fileno(stderr)))
1303 unset_nonblock(fileno(stderr));
1306 * If there was no shell or command requested, there will be no remote
1307 * exit status to be returned. In that case, clear error code if the
1308 * connection was deliberately terminated at this end.
1310 if (no_shell_flag && received_signal == SIGTERM) {
1311 received_signal = 0;
1315 if (received_signal)
1316 fatal("Killed by signal %d.", (int) received_signal);
1319 * In interactive mode (with pseudo tty) display a message indicating
1320 * that the connection has been closed.
1322 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1323 snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host);
1324 buffer_append(&stderr_buffer, buf, strlen(buf));
1327 /* Output any buffered data for stdout. */
1328 while (buffer_len(&stdout_buffer) > 0) {
1329 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1330 buffer_len(&stdout_buffer));
1332 error("Write failed flushing stdout buffer.");
1335 buffer_consume(&stdout_buffer, len);
1336 stdout_bytes += len;
1339 /* Output any buffered data for stderr. */
1340 while (buffer_len(&stderr_buffer) > 0) {
1341 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1342 buffer_len(&stderr_buffer));
1344 error("Write failed flushing stderr buffer.");
1347 buffer_consume(&stderr_buffer, len);
1348 stderr_bytes += len;
1351 /* Clear and free any buffers. */
1352 memset(buf, 0, sizeof(buf));
1353 buffer_free(&stdin_buffer);
1354 buffer_free(&stdout_buffer);
1355 buffer_free(&stderr_buffer);
1357 /* Report bytes transferred, and transfer rates. */
1358 total_time = get_current_time() - start_time;
1359 debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds",
1360 stdin_bytes, stdout_bytes, stderr_bytes, total_time);
1362 debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f",
1363 stdin_bytes / total_time, stdout_bytes / total_time,
1364 stderr_bytes / total_time);
1366 /* Return the exit status of the program. */
1367 debug("Exit status %d", exit_status);
1374 client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
1377 char *data = packet_get_string(&data_len);
1379 buffer_append(&stdout_buffer, data, data_len);
1380 memset(data, 0, data_len);
1384 client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
1387 char *data = packet_get_string(&data_len);
1389 buffer_append(&stderr_buffer, data, data_len);
1390 memset(data, 0, data_len);
1394 client_input_exit_status(int type, u_int32_t seq, void *ctxt)
1396 exit_status = packet_get_int();
1398 /* Acknowledge the exit. */
1399 packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1402 * Must wait for packet to be sent since we are
1405 packet_write_wait();
1406 /* Flag that we want to exit. */
1410 client_input_agent_open(int type, u_int32_t seq, void *ctxt)
1413 int remote_id, sock;
1415 /* Read the remote channel number from the message. */
1416 remote_id = packet_get_int();
1420 * Get a connection to the local authentication agent (this may again
1423 sock = ssh_get_authentication_socket();
1426 * If we could not connect the agent, send an error message back to
1427 * the server. This should never happen unless the agent dies,
1428 * because authentication forwarding is only enabled if we have an
1432 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
1433 -1, 0, 0, 0, "authentication agent connection", 1);
1434 c->remote_id = remote_id;
1438 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1439 packet_put_int(remote_id);
1441 /* Send a confirmation to the remote host. */
1442 debug("Forwarding authentication connection.");
1443 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1444 packet_put_int(remote_id);
1445 packet_put_int(c->self);
1451 client_request_forwarded_tcpip(const char *request_type, int rchan)
1454 char *listen_address, *originator_address;
1455 int listen_port, originator_port;
1458 /* Get rest of the packet */
1459 listen_address = packet_get_string(NULL);
1460 listen_port = packet_get_int();
1461 originator_address = packet_get_string(NULL);
1462 originator_port = packet_get_int();
1465 debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d",
1466 listen_address, listen_port, originator_address, originator_port);
1468 sock = channel_connect_by_listen_address(listen_port);
1470 xfree(originator_address);
1471 xfree(listen_address);
1474 c = channel_new("forwarded-tcpip",
1475 SSH_CHANNEL_CONNECTING, sock, sock, -1,
1476 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1477 originator_address, 1);
1478 xfree(originator_address);
1479 xfree(listen_address);
1484 client_request_x11(const char *request_type, int rchan)
1488 int originator_port;
1491 if (!options.forward_x11) {
1492 error("Warning: ssh server tried X11 forwarding.");
1493 error("Warning: this is probably a break in attempt by a malicious server.");
1496 originator = packet_get_string(NULL);
1497 if (datafellows & SSH_BUG_X11FWD) {
1498 debug2("buggy server: x11 request w/o originator_port");
1499 originator_port = 0;
1501 originator_port = packet_get_int();
1504 /* XXX check permission */
1505 debug("client_request_x11: request from %s %d", originator,
1508 sock = x11_connect_display();
1511 c = channel_new("x11",
1512 SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1513 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1519 client_request_agent(const char *request_type, int rchan)
1524 if (!options.forward_agent) {
1525 error("Warning: ssh server tried agent forwarding.");
1526 error("Warning: this is probably a break in attempt by a malicious server.");
1529 sock = ssh_get_authentication_socket();
1532 c = channel_new("authentication agent connection",
1533 SSH_CHANNEL_OPEN, sock, sock, -1,
1534 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0,
1535 "authentication agent connection", 1);
1540 /* XXXX move to generic input handler */
1542 client_input_channel_open(int type, u_int32_t seq, void *ctxt)
1547 u_int rmaxpack, rwindow, len;
1549 ctype = packet_get_string(&len);
1550 rchan = packet_get_int();
1551 rwindow = packet_get_int();
1552 rmaxpack = packet_get_int();
1554 debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1555 ctype, rchan, rwindow, rmaxpack);
1557 if (strcmp(ctype, "forwarded-tcpip") == 0) {
1558 c = client_request_forwarded_tcpip(ctype, rchan);
1559 } else if (strcmp(ctype, "x11") == 0) {
1560 c = client_request_x11(ctype, rchan);
1561 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1562 c = client_request_agent(ctype, rchan);
1564 /* XXX duplicate : */
1566 debug("confirm %s", ctype);
1567 c->remote_id = rchan;
1568 c->remote_window = rwindow;
1569 c->remote_maxpacket = rmaxpack;
1570 if (c->type != SSH_CHANNEL_CONNECTING) {
1571 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1572 packet_put_int(c->remote_id);
1573 packet_put_int(c->self);
1574 packet_put_int(c->local_window);
1575 packet_put_int(c->local_maxpacket);
1579 debug("failure %s", ctype);
1580 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1581 packet_put_int(rchan);
1582 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
1583 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1584 packet_put_cstring("open failed");
1585 packet_put_cstring("");
1592 client_input_channel_req(int type, u_int32_t seq, void *ctxt)
1595 int exitval, id, reply, success = 0;
1598 id = packet_get_int();
1599 rtype = packet_get_string(NULL);
1600 reply = packet_get_char();
1602 debug("client_input_channel_req: channel %d rtype %s reply %d",
1606 error("client_input_channel_req: request for channel -1");
1607 } else if ((c = channel_lookup(id)) == NULL) {
1608 error("client_input_channel_req: channel %d: unknown channel", id);
1609 } else if (strcmp(rtype, "exit-status") == 0) {
1610 exitval = packet_get_int();
1611 if (id == session_ident) {
1613 exit_status = exitval;
1614 } else if (c->ctl_fd == -1) {
1615 error("client_input_channel_req: unexpected channel %d",
1618 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval));
1624 packet_start(success ?
1625 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
1632 client_input_global_request(int type, u_int32_t seq, void *ctxt)
1638 rtype = packet_get_string(NULL);
1639 want_reply = packet_get_char();
1640 debug("client_input_global_request: rtype %s want_reply %d",
1643 packet_start(success ?
1644 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
1646 packet_write_wait();
1652 client_session2_setup(int id, int want_tty, int want_subsystem,
1653 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env,
1654 dispatch_fn *subsys_repl)
1659 debug2("%s: id %d", __func__, id);
1661 if ((c = channel_lookup(id)) == NULL)
1662 fatal("client_session2_setup: channel %d: unknown channel", id);
1668 /* Store window size in the packet. */
1669 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
1670 memset(&ws, 0, sizeof(ws));
1672 channel_request_start(id, "pty-req", 0);
1673 packet_put_cstring(term != NULL ? term : "");
1674 packet_put_int(ws.ws_col);
1675 packet_put_int(ws.ws_row);
1676 packet_put_int(ws.ws_xpixel);
1677 packet_put_int(ws.ws_ypixel);
1678 tio = get_saved_tio();
1679 tty_make_modes(-1, tiop != NULL ? tiop : &tio);
1681 /* XXX wait for reply */
1685 /* Transfer any environment variables from client to server */
1686 if (options.num_send_env != 0 && env != NULL) {
1690 debug("Sending environment.");
1691 for (i = 0; env[i] != NULL; i++) {
1693 name = xstrdup(env[i]);
1694 if ((val = strchr(name, '=')) == NULL) {
1701 for (j = 0; j < options.num_send_env; j++) {
1702 if (match_pattern(name, options.send_env[j])) {
1708 debug3("Ignored env %s", name);
1713 debug("Sending env %s = %s", name, val);
1714 channel_request_start(id, "env", 0);
1715 packet_put_cstring(name);
1716 packet_put_cstring(val);
1722 len = buffer_len(cmd);
1726 if (want_subsystem) {
1727 debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd));
1728 channel_request_start(id, "subsystem", subsys_repl != NULL);
1729 if (subsys_repl != NULL) {
1730 /* register callback for reply */
1731 /* XXX we assume that client_loop has already been called */
1732 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl);
1733 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl);
1736 debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd));
1737 channel_request_start(id, "exec", 0);
1739 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
1742 channel_request_start(id, "shell", 0);
1748 client_init_dispatch_20(void)
1750 dispatch_init(&dispatch_protocol_error);
1752 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
1753 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
1754 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
1755 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
1756 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
1757 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1758 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1759 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
1760 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
1761 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
1764 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1766 /* global request reply messages */
1767 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
1768 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
1771 client_init_dispatch_13(void)
1773 dispatch_init(NULL);
1774 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
1775 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
1776 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
1777 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
1778 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
1779 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
1780 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
1781 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
1782 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
1784 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
1785 &client_input_agent_open : &deny_input_open);
1786 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
1787 &x11_input_open : &deny_input_open);
1790 client_init_dispatch_15(void)
1792 client_init_dispatch_13();
1793 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
1794 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
1797 client_init_dispatch(void)
1800 client_init_dispatch_20();
1802 client_init_dispatch_13();
1804 client_init_dispatch_15();
1807 /* client specific fatal cleanup */
1812 leave_non_blocking();
1813 if (options.control_path != NULL && control_fd != -1)
1814 unlink(options.control_path);