1 /* $OpenBSD: clientloop.c,v 1.291 2017/03/10 05:01:13 djm Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * The main loop for the interactive session (client side).
7 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
13 *
14 *
15 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 *
38 * SSH2 support added by Markus Friedl.
39 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved.
40 *
41 * Redistribution and use in source and binary forms, with or without
42 * modification, are permitted provided that the following conditions
43 * are met:
44 * 1. Redistributions of source code must retain the above copyright
45 * notice, this list of conditions and the following disclaimer.
46 * 2. Redistributions in binary form must reproduce the above copyright
47 * notice, this list of conditions and the following disclaimer in the
48 * documentation and/or other materials provided with the distribution.
49 *
50 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
51 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
52 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
53 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
54 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
55 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
56 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
57 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
58 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
59 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
60 */
61
62 #include "includes.h"
63
64 #include <sys/types.h>
65 #include <sys/ioctl.h>
66 #ifdef HAVE_SYS_STAT_H
67 # include <sys/stat.h>
68 #endif
69 #ifdef HAVE_SYS_TIME_H
70 # include <sys/time.h>
71 #endif
72 #include <sys/socket.h>
73
74 #include <ctype.h>
75 #include <errno.h>
76 #ifdef HAVE_PATHS_H
77 #include <paths.h>
78 #endif
79 #include <signal.h>
80 #include <stdarg.h>
81 #include <stdio.h>
82 #include <stdlib.h>
83 #include <string.h>
84 #include <termios.h>
85 #include <pwd.h>
86 #include <unistd.h>
87 #include <limits.h>
88
89 #include "openbsd-compat/sys-queue.h"
90 #include "xmalloc.h"
91 #include "ssh.h"
92 #include "ssh1.h"
93 #include "ssh2.h"
94 #include "packet.h"
95 #include "buffer.h"
96 #include "compat.h"
97 #include "channels.h"
98 #include "dispatch.h"
99 #include "key.h"
100 #include "cipher.h"
101 #include "kex.h"
102 #include "myproposal.h"
103 #include "log.h"
104 #include "misc.h"
105 #include "readconf.h"
106 #include "clientloop.h"
107 #include "sshconnect.h"
108 #include "authfd.h"
109 #include "atomicio.h"
110 #include "sshpty.h"
111 #include "match.h"
112 #include "msg.h"
113 #include "ssherr.h"
114 #include "hostfile.h"
115
116 /* import options */
117 extern Options options;
118
119 /* Flag indicating that stdin should be redirected from /dev/null. */
120 extern int stdin_null_flag;
121
122 /* Flag indicating that no shell has been requested */
123 extern int no_shell_flag;
124
125 /* Flag indicating that ssh should daemonise after authentication is complete */
126 extern int fork_after_authentication_flag;
127
128 /* Control socket */
129 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */
130
131 /*
132 * Name of the host we are connecting to. This is the name given on the
133 * command line, or the HostName specified for the user-supplied name in a
134 * configuration file.
135 */
136 extern char *host;
137
138 /*
139 * Flag to indicate that we have received a window change signal which has
140 * not yet been processed. This will cause a message indicating the new
141 * window size to be sent to the server a little later. This is volatile
142 * because this is updated in a signal handler.
143 */
144 static volatile sig_atomic_t received_window_change_signal = 0;
145 static volatile sig_atomic_t received_signal = 0;
146
147 /* Flag indicating whether the user's terminal is in non-blocking mode. */
148 static int in_non_blocking_mode = 0;
149
150 /* Time when backgrounded control master using ControlPersist should exit */
151 static time_t control_persist_exit_time = 0;
152
153 /* Common data for the client loop code. */
154 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
155 static int escape_char1; /* Escape character. (proto1 only) */
156 static int escape_pending1; /* Last character was an escape (proto1 only) */
157 static int last_was_cr; /* Last character was a newline. */
158 static int exit_status; /* Used to store the command exit status. */
159 static int stdin_eof; /* EOF has been encountered on stderr. */
160 static Buffer stdin_buffer; /* Buffer for stdin data. */
161 static Buffer stdout_buffer; /* Buffer for stdout data. */
162 static Buffer stderr_buffer; /* Buffer for stderr data. */
163 static u_int buffer_high; /* Soft max buffer size. */
164 static int connection_in; /* Connection to server (input). */
165 static int connection_out; /* Connection to server (output). */
166 static int need_rekeying; /* Set to non-zero if rekeying is requested. */
167 static int session_closed; /* In SSH2: login session closed. */
168 static u_int x11_refuse_time; /* If >0, refuse x11 opens after this time. */
169
170 static void client_init_dispatch(void);
171 int session_ident = -1;
172
173 /* Track escape per proto2 channel */
174 struct escape_filter_ctx {
175 int escape_pending;
176 int escape_char;
177 };
178
179 /* Context for channel confirmation replies */
180 struct channel_reply_ctx {
181 const char *request_type;
182 int id;
183 enum confirm_action action;
184 };
185
186 /* Global request success/failure callbacks */
187 struct global_confirm {
188 TAILQ_ENTRY(global_confirm) entry;
189 global_confirm_cb *cb;
190 void *ctx;
191 int ref_count;
192 };
193 TAILQ_HEAD(global_confirms, global_confirm);
194 static struct global_confirms global_confirms =
195 TAILQ_HEAD_INITIALIZER(global_confirms);
196
197 void ssh_process_session2_setup(int, int, int, Buffer *);
198
199 /* Restores stdin to blocking mode. */
200
201 static void
leave_non_blocking(void)202 leave_non_blocking(void)
203 {
204 if (in_non_blocking_mode) {
205 unset_nonblock(fileno(stdin));
206 in_non_blocking_mode = 0;
207 }
208 }
209
210 /* Puts stdin terminal in non-blocking mode. */
211
212 static void
enter_non_blocking(void)213 enter_non_blocking(void)
214 {
215 in_non_blocking_mode = 1;
216 set_nonblock(fileno(stdin));
217 }
218
219 /*
220 * Signal handler for the window change signal (SIGWINCH). This just sets a
221 * flag indicating that the window has changed.
222 */
223 /*ARGSUSED */
224 static void
window_change_handler(int sig)225 window_change_handler(int sig)
226 {
227 received_window_change_signal = 1;
228 signal(SIGWINCH, window_change_handler);
229 }
230
231 /*
232 * Signal handler for signals that cause the program to terminate. These
233 * signals must be trapped to restore terminal modes.
234 */
235 /*ARGSUSED */
236 static void
signal_handler(int sig)237 signal_handler(int sig)
238 {
239 received_signal = sig;
240 quit_pending = 1;
241 }
242
243 /*
244 * Returns current time in seconds from Jan 1, 1970 with the maximum
245 * available resolution.
246 */
247
248 static double
get_current_time(void)249 get_current_time(void)
250 {
251 struct timeval tv;
252 gettimeofday(&tv, NULL);
253 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0;
254 }
255
256 /*
257 * Sets control_persist_exit_time to the absolute time when the
258 * backgrounded control master should exit due to expiry of the
259 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded
260 * control master process, or if there is no ControlPersist timeout.
261 */
262 static void
set_control_persist_exit_time(void)263 set_control_persist_exit_time(void)
264 {
265 if (muxserver_sock == -1 || !options.control_persist
266 || options.control_persist_timeout == 0) {
267 /* not using a ControlPersist timeout */
268 control_persist_exit_time = 0;
269 } else if (channel_still_open()) {
270 /* some client connections are still open */
271 if (control_persist_exit_time > 0)
272 debug2("%s: cancel scheduled exit", __func__);
273 control_persist_exit_time = 0;
274 } else if (control_persist_exit_time <= 0) {
275 /* a client connection has recently closed */
276 control_persist_exit_time = monotime() +
277 (time_t)options.control_persist_timeout;
278 debug2("%s: schedule exit in %d seconds", __func__,
279 options.control_persist_timeout);
280 }
281 /* else we are already counting down to the timeout */
282 }
283
284 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_"
285 static int
client_x11_display_valid(const char * display)286 client_x11_display_valid(const char *display)
287 {
288 size_t i, dlen;
289
290 if (display == NULL)
291 return 0;
292
293 dlen = strlen(display);
294 for (i = 0; i < dlen; i++) {
295 if (!isalnum((u_char)display[i]) &&
296 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) {
297 debug("Invalid character '%c' in DISPLAY", display[i]);
298 return 0;
299 }
300 }
301 return 1;
302 }
303
304 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
305 #define X11_TIMEOUT_SLACK 60
306 int
client_x11_get_proto(const char * display,const char * xauth_path,u_int trusted,u_int timeout,char ** _proto,char ** _data)307 client_x11_get_proto(const char *display, const char *xauth_path,
308 u_int trusted, u_int timeout, char **_proto, char **_data)
309 {
310 char cmd[1024], line[512], xdisplay[512];
311 char xauthfile[PATH_MAX], xauthdir[PATH_MAX];
312 static char proto[512], data[512];
313 FILE *f;
314 int got_data = 0, generated = 0, do_unlink = 0, r;
315 struct stat st;
316 u_int now, x11_timeout_real;
317
318 *_proto = proto;
319 *_data = data;
320 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0';
321
322 if (!client_x11_display_valid(display)) {
323 if (display != NULL)
324 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding",
325 display);
326 return -1;
327 }
328 if (xauth_path != NULL && stat(xauth_path, &st) == -1) {
329 debug("No xauth program.");
330 xauth_path = NULL;
331 }
332
333 if (xauth_path != NULL) {
334 /*
335 * Handle FamilyLocal case where $DISPLAY does
336 * not match an authorization entry. For this we
337 * just try "xauth list unix:displaynum.screennum".
338 * XXX: "localhost" match to determine FamilyLocal
339 * is not perfect.
340 */
341 if (strncmp(display, "localhost:", 10) == 0) {
342 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
343 display + 10)) < 0 ||
344 (size_t)r >= sizeof(xdisplay)) {
345 error("%s: display name too long", __func__);
346 return -1;
347 }
348 display = xdisplay;
349 }
350 if (trusted == 0) {
351 /*
352 * Generate an untrusted X11 auth cookie.
353 *
354 * The authentication cookie should briefly outlive
355 * ssh's willingness to forward X11 connections to
356 * avoid nasty fail-open behaviour in the X server.
357 */
358 mktemp_proto(xauthdir, sizeof(xauthdir));
359 if (mkdtemp(xauthdir) == NULL) {
360 error("%s: mkdtemp: %s",
361 __func__, strerror(errno));
362 return -1;
363 }
364 do_unlink = 1;
365 if ((r = snprintf(xauthfile, sizeof(xauthfile),
366 "%s/xauthfile", xauthdir)) < 0 ||
367 (size_t)r >= sizeof(xauthfile)) {
368 error("%s: xauthfile path too long", __func__);
369 unlink(xauthfile);
370 rmdir(xauthdir);
371 return -1;
372 }
373
374 if (timeout >= UINT_MAX - X11_TIMEOUT_SLACK)
375 x11_timeout_real = UINT_MAX;
376 else
377 x11_timeout_real = timeout + X11_TIMEOUT_SLACK;
378 if ((r = snprintf(cmd, sizeof(cmd),
379 "%s -f %s generate %s " SSH_X11_PROTO
380 " untrusted timeout %u 2>" _PATH_DEVNULL,
381 xauth_path, xauthfile, display,
382 x11_timeout_real)) < 0 ||
383 (size_t)r >= sizeof(cmd))
384 fatal("%s: cmd too long", __func__);
385 debug2("%s: %s", __func__, cmd);
386 if (x11_refuse_time == 0) {
387 now = monotime() + 1;
388 if (UINT_MAX - timeout < now)
389 x11_refuse_time = UINT_MAX;
390 else
391 x11_refuse_time = now + timeout;
392 channel_set_x11_refuse_time(x11_refuse_time);
393 }
394 if (system(cmd) == 0)
395 generated = 1;
396 }
397
398 /*
399 * When in untrusted mode, we read the cookie only if it was
400 * successfully generated as an untrusted one in the step
401 * above.
402 */
403 if (trusted || generated) {
404 snprintf(cmd, sizeof(cmd),
405 "%s %s%s list %s 2>" _PATH_DEVNULL,
406 xauth_path,
407 generated ? "-f " : "" ,
408 generated ? xauthfile : "",
409 display);
410 debug2("x11_get_proto: %s", cmd);
411 f = popen(cmd, "r");
412 if (f && fgets(line, sizeof(line), f) &&
413 sscanf(line, "%*s %511s %511s", proto, data) == 2)
414 got_data = 1;
415 if (f)
416 pclose(f);
417 }
418 }
419
420 if (do_unlink) {
421 unlink(xauthfile);
422 rmdir(xauthdir);
423 }
424
425 /* Don't fall back to fake X11 data for untrusted forwarding */
426 if (!trusted && !got_data) {
427 error("Warning: untrusted X11 forwarding setup failed: "
428 "xauth key data not generated");
429 return -1;
430 }
431
432 /*
433 * If we didn't get authentication data, just make up some
434 * data. The forwarding code will check the validity of the
435 * response anyway, and substitute this data. The X11
436 * server, however, will ignore this fake data and use
437 * whatever authentication mechanisms it was using otherwise
438 * for the local connection.
439 */
440 if (!got_data) {
441 u_int8_t rnd[16];
442 u_int i;
443
444 logit("Warning: No xauth data; "
445 "using fake authentication data for X11 forwarding.");
446 strlcpy(proto, SSH_X11_PROTO, sizeof proto);
447 arc4random_buf(rnd, sizeof(rnd));
448 for (i = 0; i < sizeof(rnd); i++) {
449 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
450 rnd[i]);
451 }
452 }
453
454 return 0;
455 }
456
457 /*
458 * This is called when the interactive is entered. This checks if there is
459 * an EOF coming on stdin. We must check this explicitly, as select() does
460 * not appear to wake up when redirecting from /dev/null.
461 */
462
463 static void
client_check_initial_eof_on_stdin(void)464 client_check_initial_eof_on_stdin(void)
465 {
466 int len;
467 char buf[1];
468
469 /*
470 * If standard input is to be "redirected from /dev/null", we simply
471 * mark that we have seen an EOF and send an EOF message to the
472 * server. Otherwise, we try to read a single character; it appears
473 * that for some files, such /dev/null, select() never wakes up for
474 * read for this descriptor, which means that we never get EOF. This
475 * way we will get the EOF if stdin comes from /dev/null or similar.
476 */
477 if (stdin_null_flag) {
478 /* Fake EOF on stdin. */
479 debug("Sending eof.");
480 stdin_eof = 1;
481 packet_start(SSH_CMSG_EOF);
482 packet_send();
483 } else {
484 enter_non_blocking();
485
486 /* Check for immediate EOF on stdin. */
487 len = read(fileno(stdin), buf, 1);
488 if (len == 0) {
489 /*
490 * EOF. Record that we have seen it and send
491 * EOF to server.
492 */
493 debug("Sending eof.");
494 stdin_eof = 1;
495 packet_start(SSH_CMSG_EOF);
496 packet_send();
497 } else if (len > 0) {
498 /*
499 * Got data. We must store the data in the buffer,
500 * and also process it as an escape character if
501 * appropriate.
502 */
503 if ((u_char) buf[0] == escape_char1)
504 escape_pending1 = 1;
505 else
506 buffer_append(&stdin_buffer, buf, 1);
507 }
508 leave_non_blocking();
509 }
510 }
511
512
513 /*
514 * Make packets from buffered stdin data, and buffer them for sending to the
515 * connection.
516 */
517
518 static void
client_make_packets_from_stdin_data(void)519 client_make_packets_from_stdin_data(void)
520 {
521 u_int len;
522
523 /* Send buffered stdin data to the server. */
524 while (buffer_len(&stdin_buffer) > 0 &&
525 packet_not_very_much_data_to_write()) {
526 len = buffer_len(&stdin_buffer);
527 /* Keep the packets at reasonable size. */
528 if (len > packet_get_maxsize())
529 len = packet_get_maxsize();
530 packet_start(SSH_CMSG_STDIN_DATA);
531 packet_put_string(buffer_ptr(&stdin_buffer), len);
532 packet_send();
533 buffer_consume(&stdin_buffer, len);
534 /* If we have a pending EOF, send it now. */
535 if (stdin_eof && buffer_len(&stdin_buffer) == 0) {
536 packet_start(SSH_CMSG_EOF);
537 packet_send();
538 }
539 }
540 }
541
542 /*
543 * Checks if the client window has changed, and sends a packet about it to
544 * the server if so. The actual change is detected elsewhere (by a software
545 * interrupt on Unix); this just checks the flag and sends a message if
546 * appropriate.
547 */
548
549 static void
client_check_window_change(void)550 client_check_window_change(void)
551 {
552 struct winsize ws;
553
554 if (! received_window_change_signal)
555 return;
556 /** XXX race */
557 received_window_change_signal = 0;
558
559 debug2("client_check_window_change: changed");
560
561 if (compat20) {
562 channel_send_window_changes();
563 } else {
564 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
565 return;
566 packet_start(SSH_CMSG_WINDOW_SIZE);
567 packet_put_int((u_int)ws.ws_row);
568 packet_put_int((u_int)ws.ws_col);
569 packet_put_int((u_int)ws.ws_xpixel);
570 packet_put_int((u_int)ws.ws_ypixel);
571 packet_send();
572 }
573 }
574
575 static int
client_global_request_reply(int type,u_int32_t seq,void * ctxt)576 client_global_request_reply(int type, u_int32_t seq, void *ctxt)
577 {
578 struct global_confirm *gc;
579
580 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL)
581 return 0;
582 if (gc->cb != NULL)
583 gc->cb(type, seq, gc->ctx);
584 if (--gc->ref_count <= 0) {
585 TAILQ_REMOVE(&global_confirms, gc, entry);
586 explicit_bzero(gc, sizeof(*gc));
587 free(gc);
588 }
589
590 packet_set_alive_timeouts(0);
591 return 0;
592 }
593
594 static void
server_alive_check(void)595 server_alive_check(void)
596 {
597 if (packet_inc_alive_timeouts() > options.server_alive_count_max) {
598 logit("Timeout, server %s not responding.", host);
599 cleanup_exit(255);
600 }
601 packet_start(SSH2_MSG_GLOBAL_REQUEST);
602 packet_put_cstring("keepalive@openssh.com");
603 packet_put_char(1); /* boolean: want reply */
604 packet_send();
605 /* Insert an empty placeholder to maintain ordering */
606 client_register_global_confirm(NULL, NULL);
607 }
608
609 /*
610 * Waits until the client can do something (some data becomes available on
611 * one of the file descriptors).
612 */
613 static void
client_wait_until_can_do_something(fd_set ** readsetp,fd_set ** writesetp,int * maxfdp,u_int * nallocp,int rekeying)614 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
615 int *maxfdp, u_int *nallocp, int rekeying)
616 {
617 struct timeval tv, *tvp;
618 int timeout_secs;
619 time_t minwait_secs = 0, server_alive_time = 0, now = monotime();
620 int ret;
621
622 /* Add any selections by the channel mechanism. */
623 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp,
624 &minwait_secs, rekeying);
625
626 if (!compat20) {
627 /* Read from the connection, unless our buffers are full. */
628 if (buffer_len(&stdout_buffer) < buffer_high &&
629 buffer_len(&stderr_buffer) < buffer_high &&
630 channel_not_very_much_buffered_data())
631 FD_SET(connection_in, *readsetp);
632 /*
633 * Read from stdin, unless we have seen EOF or have very much
634 * buffered data to send to the server.
635 */
636 if (!stdin_eof && packet_not_very_much_data_to_write())
637 FD_SET(fileno(stdin), *readsetp);
638
639 /* Select stdout/stderr if have data in buffer. */
640 if (buffer_len(&stdout_buffer) > 0)
641 FD_SET(fileno(stdout), *writesetp);
642 if (buffer_len(&stderr_buffer) > 0)
643 FD_SET(fileno(stderr), *writesetp);
644 } else {
645 /* channel_prepare_select could have closed the last channel */
646 if (session_closed && !channel_still_open() &&
647 !packet_have_data_to_write()) {
648 /* clear mask since we did not call select() */
649 memset(*readsetp, 0, *nallocp);
650 memset(*writesetp, 0, *nallocp);
651 return;
652 } else {
653 FD_SET(connection_in, *readsetp);
654 }
655 }
656
657 /* Select server connection if have data to write to the server. */
658 if (packet_have_data_to_write())
659 FD_SET(connection_out, *writesetp);
660
661 /*
662 * Wait for something to happen. This will suspend the process until
663 * some selected descriptor can be read, written, or has some other
664 * event pending, or a timeout expires.
665 */
666
667 timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */
668 if (options.server_alive_interval > 0 && compat20) {
669 timeout_secs = options.server_alive_interval;
670 server_alive_time = now + options.server_alive_interval;
671 }
672 if (options.rekey_interval > 0 && compat20 && !rekeying)
673 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout());
674 set_control_persist_exit_time();
675 if (control_persist_exit_time > 0) {
676 timeout_secs = MINIMUM(timeout_secs,
677 control_persist_exit_time - now);
678 if (timeout_secs < 0)
679 timeout_secs = 0;
680 }
681 if (minwait_secs != 0)
682 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs);
683 if (timeout_secs == INT_MAX)
684 tvp = NULL;
685 else {
686 tv.tv_sec = timeout_secs;
687 tv.tv_usec = 0;
688 tvp = &tv;
689 }
690
691 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
692 if (ret < 0) {
693 char buf[100];
694
695 /*
696 * We have to clear the select masks, because we return.
697 * We have to return, because the mainloop checks for the flags
698 * set by the signal handlers.
699 */
700 memset(*readsetp, 0, *nallocp);
701 memset(*writesetp, 0, *nallocp);
702
703 if (errno == EINTR)
704 return;
705 /* Note: we might still have data in the buffers. */
706 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno));
707 buffer_append(&stderr_buffer, buf, strlen(buf));
708 quit_pending = 1;
709 } else if (ret == 0) {
710 /*
711 * Timeout. Could have been either keepalive or rekeying.
712 * Keepalive we check here, rekeying is checked in clientloop.
713 */
714 if (server_alive_time != 0 && server_alive_time <= monotime())
715 server_alive_check();
716 }
717
718 }
719
720 static void
client_suspend_self(Buffer * bin,Buffer * bout,Buffer * berr)721 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
722 {
723 /* Flush stdout and stderr buffers. */
724 if (buffer_len(bout) > 0)
725 atomicio(vwrite, fileno(stdout), buffer_ptr(bout),
726 buffer_len(bout));
727 if (buffer_len(berr) > 0)
728 atomicio(vwrite, fileno(stderr), buffer_ptr(berr),
729 buffer_len(berr));
730
731 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
732
733 /*
734 * Free (and clear) the buffer to reduce the amount of data that gets
735 * written to swap.
736 */
737 buffer_free(bin);
738 buffer_free(bout);
739 buffer_free(berr);
740
741 /* Send the suspend signal to the program itself. */
742 kill(getpid(), SIGTSTP);
743
744 /* Reset window sizes in case they have changed */
745 received_window_change_signal = 1;
746
747 /* OK, we have been continued by the user. Reinitialize buffers. */
748 buffer_init(bin);
749 buffer_init(bout);
750 buffer_init(berr);
751
752 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
753 }
754
755 static void
client_process_net_input(fd_set * readset)756 client_process_net_input(fd_set *readset)
757 {
758 int len;
759 char buf[SSH_IOBUFSZ];
760
761 /*
762 * Read input from the server, and add any such data to the buffer of
763 * the packet subsystem.
764 */
765 if (FD_ISSET(connection_in, readset)) {
766 /* Read as much as possible. */
767 len = read(connection_in, buf, sizeof(buf));
768 if (len == 0) {
769 /*
770 * Received EOF. The remote host has closed the
771 * connection.
772 */
773 snprintf(buf, sizeof buf,
774 "Connection to %.300s closed by remote host.\r\n",
775 host);
776 buffer_append(&stderr_buffer, buf, strlen(buf));
777 quit_pending = 1;
778 return;
779 }
780 /*
781 * There is a kernel bug on Solaris that causes select to
782 * sometimes wake up even though there is no data available.
783 */
784 if (len < 0 &&
785 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
786 len = 0;
787
788 if (len < 0) {
789 /*
790 * An error has encountered. Perhaps there is a
791 * network problem.
792 */
793 snprintf(buf, sizeof buf,
794 "Read from remote host %.300s: %.100s\r\n",
795 host, strerror(errno));
796 buffer_append(&stderr_buffer, buf, strlen(buf));
797 quit_pending = 1;
798 return;
799 }
800 packet_process_incoming(buf, len);
801 }
802 }
803
804 static void
client_status_confirm(int type,Channel * c,void * ctx)805 client_status_confirm(int type, Channel *c, void *ctx)
806 {
807 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx;
808 char errmsg[256];
809 int tochan;
810
811 /*
812 * If a TTY was explicitly requested, then a failure to allocate
813 * one is fatal.
814 */
815 if (cr->action == CONFIRM_TTY &&
816 (options.request_tty == REQUEST_TTY_FORCE ||
817 options.request_tty == REQUEST_TTY_YES))
818 cr->action = CONFIRM_CLOSE;
819
820 /* XXX supress on mux _client_ quietmode */
821 tochan = options.log_level >= SYSLOG_LEVEL_ERROR &&
822 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;
823
824 if (type == SSH2_MSG_CHANNEL_SUCCESS) {
825 debug2("%s request accepted on channel %d",
826 cr->request_type, c->self);
827 } else if (type == SSH2_MSG_CHANNEL_FAILURE) {
828 if (tochan) {
829 snprintf(errmsg, sizeof(errmsg),
830 "%s request failed\r\n", cr->request_type);
831 } else {
832 snprintf(errmsg, sizeof(errmsg),
833 "%s request failed on channel %d",
834 cr->request_type, c->self);
835 }
836 /* If error occurred on primary session channel, then exit */
837 if (cr->action == CONFIRM_CLOSE && c->self == session_ident)
838 fatal("%s", errmsg);
839 /*
840 * If error occurred on mux client, append to
841 * their stderr.
842 */
843 if (tochan) {
844 buffer_append(&c->extended, errmsg,
845 strlen(errmsg));
846 } else
847 error("%s", errmsg);
848 if (cr->action == CONFIRM_TTY) {
849 /*
850 * If a TTY allocation error occurred, then arrange
851 * for the correct TTY to leave raw mode.
852 */
853 if (c->self == session_ident)
854 leave_raw_mode(0);
855 else
856 mux_tty_alloc_failed(c);
857 } else if (cr->action == CONFIRM_CLOSE) {
858 chan_read_failed(c);
859 chan_write_failed(c);
860 }
861 }
862 free(cr);
863 }
864
865 static void
client_abandon_status_confirm(Channel * c,void * ctx)866 client_abandon_status_confirm(Channel *c, void *ctx)
867 {
868 free(ctx);
869 }
870
871 void
client_expect_confirm(int id,const char * request,enum confirm_action action)872 client_expect_confirm(int id, const char *request,
873 enum confirm_action action)
874 {
875 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr));
876
877 cr->request_type = request;
878 cr->action = action;
879
880 channel_register_status_confirm(id, client_status_confirm,
881 client_abandon_status_confirm, cr);
882 }
883
884 void
client_register_global_confirm(global_confirm_cb * cb,void * ctx)885 client_register_global_confirm(global_confirm_cb *cb, void *ctx)
886 {
887 struct global_confirm *gc, *last_gc;
888
889 /* Coalesce identical callbacks */
890 last_gc = TAILQ_LAST(&global_confirms, global_confirms);
891 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) {
892 if (++last_gc->ref_count >= INT_MAX)
893 fatal("%s: last_gc->ref_count = %d",
894 __func__, last_gc->ref_count);
895 return;
896 }
897
898 gc = xcalloc(1, sizeof(*gc));
899 gc->cb = cb;
900 gc->ctx = ctx;
901 gc->ref_count = 1;
902 TAILQ_INSERT_TAIL(&global_confirms, gc, entry);
903 }
904
905 static void
process_cmdline(void)906 process_cmdline(void)
907 {
908 void (*handler)(int);
909 char *s, *cmd;
910 int ok, delete = 0, local = 0, remote = 0, dynamic = 0;
911 struct Forward fwd;
912
913 memset(&fwd, 0, sizeof(fwd));
914
915 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
916 handler = signal(SIGINT, SIG_IGN);
917 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
918 if (s == NULL)
919 goto out;
920 while (isspace((u_char)*s))
921 s++;
922 if (*s == '-')
923 s++; /* Skip cmdline '-', if any */
924 if (*s == '\0')
925 goto out;
926
927 if (*s == 'h' || *s == 'H' || *s == '?') {
928 logit("Commands:");
929 logit(" -L[bind_address:]port:host:hostport "
930 "Request local forward");
931 logit(" -R[bind_address:]port:host:hostport "
932 "Request remote forward");
933 logit(" -D[bind_address:]port "
934 "Request dynamic forward");
935 logit(" -KL[bind_address:]port "
936 "Cancel local forward");
937 logit(" -KR[bind_address:]port "
938 "Cancel remote forward");
939 logit(" -KD[bind_address:]port "
940 "Cancel dynamic forward");
941 if (!options.permit_local_command)
942 goto out;
943 logit(" !args "
944 "Execute local command");
945 goto out;
946 }
947
948 if (*s == '!' && options.permit_local_command) {
949 s++;
950 ssh_local_cmd(s);
951 goto out;
952 }
953
954 if (*s == 'K') {
955 delete = 1;
956 s++;
957 }
958 if (*s == 'L')
959 local = 1;
960 else if (*s == 'R')
961 remote = 1;
962 else if (*s == 'D')
963 dynamic = 1;
964 else {
965 logit("Invalid command.");
966 goto out;
967 }
968
969 if (delete && !compat20) {
970 logit("Not supported for SSH protocol version 1.");
971 goto out;
972 }
973
974 while (isspace((u_char)*++s))
975 ;
976
977 /* XXX update list of forwards in options */
978 if (delete) {
979 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */
980 if (!parse_forward(&fwd, s, 1, 0)) {
981 logit("Bad forwarding close specification.");
982 goto out;
983 }
984 if (remote)
985 ok = channel_request_rforward_cancel(&fwd) == 0;
986 else if (dynamic)
987 ok = channel_cancel_lport_listener(&fwd,
988 0, &options.fwd_opts) > 0;
989 else
990 ok = channel_cancel_lport_listener(&fwd,
991 CHANNEL_CANCEL_PORT_STATIC,
992 &options.fwd_opts) > 0;
993 if (!ok) {
994 logit("Unknown port forwarding.");
995 goto out;
996 }
997 logit("Canceled forwarding.");
998 } else {
999 if (!parse_forward(&fwd, s, dynamic, remote)) {
1000 logit("Bad forwarding specification.");
1001 goto out;
1002 }
1003 if (local || dynamic) {
1004 if (!channel_setup_local_fwd_listener(&fwd,
1005 &options.fwd_opts)) {
1006 logit("Port forwarding failed.");
1007 goto out;
1008 }
1009 } else {
1010 if (channel_request_remote_forwarding(&fwd) < 0) {
1011 logit("Port forwarding failed.");
1012 goto out;
1013 }
1014 }
1015 logit("Forwarding port.");
1016 }
1017
1018 out:
1019 signal(SIGINT, handler);
1020 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1021 free(cmd);
1022 free(fwd.listen_host);
1023 free(fwd.listen_path);
1024 free(fwd.connect_host);
1025 free(fwd.connect_path);
1026 }
1027
1028 /* reasons to suppress output of an escape command in help output */
1029 #define SUPPRESS_NEVER 0 /* never suppress, always show */
1030 #define SUPPRESS_PROTO1 1 /* don't show in protocol 1 sessions */
1031 #define SUPPRESS_MUXCLIENT 2 /* don't show in mux client sessions */
1032 #define SUPPRESS_MUXMASTER 4 /* don't show in mux master sessions */
1033 #define SUPPRESS_SYSLOG 8 /* don't show when logging to syslog */
1034 struct escape_help_text {
1035 const char *cmd;
1036 const char *text;
1037 unsigned int flags;
1038 };
1039 static struct escape_help_text esc_txt[] = {
1040 {".", "terminate session", SUPPRESS_MUXMASTER},
1041 {".", "terminate connection (and any multiplexed sessions)",
1042 SUPPRESS_MUXCLIENT},
1043 {"B", "send a BREAK to the remote system", SUPPRESS_PROTO1},
1044 {"C", "open a command line", SUPPRESS_MUXCLIENT},
1045 {"R", "request rekey", SUPPRESS_PROTO1},
1046 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT},
1047 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT},
1048 {"#", "list forwarded connections", SUPPRESS_NEVER},
1049 {"&", "background ssh (when waiting for connections to terminate)",
1050 SUPPRESS_MUXCLIENT},
1051 {"?", "this message", SUPPRESS_NEVER},
1052 };
1053
1054 static void
print_escape_help(Buffer * b,int escape_char,int protocol2,int mux_client,int using_stderr)1055 print_escape_help(Buffer *b, int escape_char, int protocol2, int mux_client,
1056 int using_stderr)
1057 {
1058 unsigned int i, suppress_flags;
1059 char string[1024];
1060
1061 snprintf(string, sizeof string, "%c?\r\n"
1062 "Supported escape sequences:\r\n", escape_char);
1063 buffer_append(b, string, strlen(string));
1064
1065 suppress_flags = (protocol2 ? 0 : SUPPRESS_PROTO1) |
1066 (mux_client ? SUPPRESS_MUXCLIENT : 0) |
1067 (mux_client ? 0 : SUPPRESS_MUXMASTER) |
1068 (using_stderr ? 0 : SUPPRESS_SYSLOG);
1069
1070 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) {
1071 if (esc_txt[i].flags & suppress_flags)
1072 continue;
1073 snprintf(string, sizeof string, " %c%-3s - %s\r\n",
1074 escape_char, esc_txt[i].cmd, esc_txt[i].text);
1075 buffer_append(b, string, strlen(string));
1076 }
1077
1078 snprintf(string, sizeof string,
1079 " %c%c - send the escape character by typing it twice\r\n"
1080 "(Note that escapes are only recognized immediately after "
1081 "newline.)\r\n", escape_char, escape_char);
1082 buffer_append(b, string, strlen(string));
1083 }
1084
1085 /*
1086 * Process the characters one by one, call with c==NULL for proto1 case.
1087 */
1088 static int
process_escapes(Channel * c,Buffer * bin,Buffer * bout,Buffer * berr,char * buf,int len)1089 process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr,
1090 char *buf, int len)
1091 {
1092 char string[1024];
1093 pid_t pid;
1094 int bytes = 0;
1095 u_int i;
1096 u_char ch;
1097 char *s;
1098 int *escape_pendingp, escape_char;
1099 struct escape_filter_ctx *efc;
1100
1101 if (c == NULL) {
1102 escape_pendingp = &escape_pending1;
1103 escape_char = escape_char1;
1104 } else {
1105 if (c->filter_ctx == NULL)
1106 return 0;
1107 efc = (struct escape_filter_ctx *)c->filter_ctx;
1108 escape_pendingp = &efc->escape_pending;
1109 escape_char = efc->escape_char;
1110 }
1111
1112 if (len <= 0)
1113 return (0);
1114
1115 for (i = 0; i < (u_int)len; i++) {
1116 /* Get one character at a time. */
1117 ch = buf[i];
1118
1119 if (*escape_pendingp) {
1120 /* We have previously seen an escape character. */
1121 /* Clear the flag now. */
1122 *escape_pendingp = 0;
1123
1124 /* Process the escaped character. */
1125 switch (ch) {
1126 case '.':
1127 /* Terminate the connection. */
1128 snprintf(string, sizeof string, "%c.\r\n",
1129 escape_char);
1130 buffer_append(berr, string, strlen(string));
1131
1132 if (c && c->ctl_chan != -1) {
1133 chan_read_failed(c);
1134 chan_write_failed(c);
1135 if (c->detach_user)
1136 c->detach_user(c->self, NULL);
1137 c->type = SSH_CHANNEL_ABANDONED;
1138 buffer_clear(&c->input);
1139 chan_ibuf_empty(c);
1140 return 0;
1141 } else
1142 quit_pending = 1;
1143 return -1;
1144
1145 case 'Z' - 64:
1146 /* XXX support this for mux clients */
1147 if (c && c->ctl_chan != -1) {
1148 char b[16];
1149 noescape:
1150 if (ch == 'Z' - 64)
1151 snprintf(b, sizeof b, "^Z");
1152 else
1153 snprintf(b, sizeof b, "%c", ch);
1154 snprintf(string, sizeof string,
1155 "%c%s escape not available to "
1156 "multiplexed sessions\r\n",
1157 escape_char, b);
1158 buffer_append(berr, string,
1159 strlen(string));
1160 continue;
1161 }
1162 /* Suspend the program. Inform the user */
1163 snprintf(string, sizeof string,
1164 "%c^Z [suspend ssh]\r\n", escape_char);
1165 buffer_append(berr, string, strlen(string));
1166
1167 /* Restore terminal modes and suspend. */
1168 client_suspend_self(bin, bout, berr);
1169
1170 /* We have been continued. */
1171 continue;
1172
1173 case 'B':
1174 if (compat20) {
1175 snprintf(string, sizeof string,
1176 "%cB\r\n", escape_char);
1177 buffer_append(berr, string,
1178 strlen(string));
1179 channel_request_start(c->self,
1180 "break", 0);
1181 packet_put_int(1000);
1182 packet_send();
1183 }
1184 continue;
1185
1186 case 'R':
1187 if (compat20) {
1188 if (datafellows & SSH_BUG_NOREKEY)
1189 logit("Server does not "
1190 "support re-keying");
1191 else
1192 need_rekeying = 1;
1193 }
1194 continue;
1195
1196 case 'V':
1197 /* FALLTHROUGH */
1198 case 'v':
1199 if (c && c->ctl_chan != -1)
1200 goto noescape;
1201 if (!log_is_on_stderr()) {
1202 snprintf(string, sizeof string,
1203 "%c%c [Logging to syslog]\r\n",
1204 escape_char, ch);
1205 buffer_append(berr, string,
1206 strlen(string));
1207 continue;
1208 }
1209 if (ch == 'V' && options.log_level >
1210 SYSLOG_LEVEL_QUIET)
1211 log_change_level(--options.log_level);
1212 if (ch == 'v' && options.log_level <
1213 SYSLOG_LEVEL_DEBUG3)
1214 log_change_level(++options.log_level);
1215 snprintf(string, sizeof string,
1216 "%c%c [LogLevel %s]\r\n", escape_char, ch,
1217 log_level_name(options.log_level));
1218 buffer_append(berr, string, strlen(string));
1219 continue;
1220
1221 case '&':
1222 if (c && c->ctl_chan != -1)
1223 goto noescape;
1224 /*
1225 * Detach the program (continue to serve
1226 * connections, but put in background and no
1227 * more new connections).
1228 */
1229 /* Restore tty modes. */
1230 leave_raw_mode(
1231 options.request_tty == REQUEST_TTY_FORCE);
1232
1233 /* Stop listening for new connections. */
1234 channel_stop_listening();
1235
1236 snprintf(string, sizeof string,
1237 "%c& [backgrounded]\n", escape_char);
1238 buffer_append(berr, string, strlen(string));
1239
1240 /* Fork into background. */
1241 pid = fork();
1242 if (pid < 0) {
1243 error("fork: %.100s", strerror(errno));
1244 continue;
1245 }
1246 if (pid != 0) { /* This is the parent. */
1247 /* The parent just exits. */
1248 exit(0);
1249 }
1250 /* The child continues serving connections. */
1251 if (compat20) {
1252 buffer_append(bin, "\004", 1);
1253 /* fake EOF on stdin */
1254 return -1;
1255 } else if (!stdin_eof) {
1256 /*
1257 * Sending SSH_CMSG_EOF alone does not
1258 * always appear to be enough. So we
1259 * try to send an EOF character first.
1260 */
1261 packet_start(SSH_CMSG_STDIN_DATA);
1262 packet_put_string("\004", 1);
1263 packet_send();
1264 /* Close stdin. */
1265 stdin_eof = 1;
1266 if (buffer_len(bin) == 0) {
1267 packet_start(SSH_CMSG_EOF);
1268 packet_send();
1269 }
1270 }
1271 continue;
1272
1273 case '?':
1274 print_escape_help(berr, escape_char, compat20,
1275 (c && c->ctl_chan != -1),
1276 log_is_on_stderr());
1277 continue;
1278
1279 case '#':
1280 snprintf(string, sizeof string, "%c#\r\n",
1281 escape_char);
1282 buffer_append(berr, string, strlen(string));
1283 s = channel_open_message();
1284 buffer_append(berr, s, strlen(s));
1285 free(s);
1286 continue;
1287
1288 case 'C':
1289 if (c && c->ctl_chan != -1)
1290 goto noescape;
1291 process_cmdline();
1292 continue;
1293
1294 default:
1295 if (ch != escape_char) {
1296 buffer_put_char(bin, escape_char);
1297 bytes++;
1298 }
1299 /* Escaped characters fall through here */
1300 break;
1301 }
1302 } else {
1303 /*
1304 * The previous character was not an escape char.
1305 * Check if this is an escape.
1306 */
1307 if (last_was_cr && ch == escape_char) {
1308 /*
1309 * It is. Set the flag and continue to
1310 * next character.
1311 */
1312 *escape_pendingp = 1;
1313 continue;
1314 }
1315 }
1316
1317 /*
1318 * Normal character. Record whether it was a newline,
1319 * and append it to the buffer.
1320 */
1321 last_was_cr = (ch == '\r' || ch == '\n');
1322 buffer_put_char(bin, ch);
1323 bytes++;
1324 }
1325 return bytes;
1326 }
1327
1328 static void
client_process_input(fd_set * readset)1329 client_process_input(fd_set *readset)
1330 {
1331 int len;
1332 char buf[SSH_IOBUFSZ];
1333
1334 /* Read input from stdin. */
1335 if (FD_ISSET(fileno(stdin), readset)) {
1336 /* Read as much as possible. */
1337 len = read(fileno(stdin), buf, sizeof(buf));
1338 if (len < 0 &&
1339 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
1340 return; /* we'll try again later */
1341 if (len <= 0) {
1342 /*
1343 * Received EOF or error. They are treated
1344 * similarly, except that an error message is printed
1345 * if it was an error condition.
1346 */
1347 if (len < 0) {
1348 snprintf(buf, sizeof buf, "read: %.100s\r\n",
1349 strerror(errno));
1350 buffer_append(&stderr_buffer, buf, strlen(buf));
1351 }
1352 /* Mark that we have seen EOF. */
1353 stdin_eof = 1;
1354 /*
1355 * Send an EOF message to the server unless there is
1356 * data in the buffer. If there is data in the
1357 * buffer, no message will be sent now. Code
1358 * elsewhere will send the EOF when the buffer
1359 * becomes empty if stdin_eof is set.
1360 */
1361 if (buffer_len(&stdin_buffer) == 0) {
1362 packet_start(SSH_CMSG_EOF);
1363 packet_send();
1364 }
1365 } else if (escape_char1 == SSH_ESCAPECHAR_NONE) {
1366 /*
1367 * Normal successful read, and no escape character.
1368 * Just append the data to buffer.
1369 */
1370 buffer_append(&stdin_buffer, buf, len);
1371 } else {
1372 /*
1373 * Normal, successful read. But we have an escape
1374 * character and have to process the characters one
1375 * by one.
1376 */
1377 if (process_escapes(NULL, &stdin_buffer,
1378 &stdout_buffer, &stderr_buffer, buf, len) == -1)
1379 return;
1380 }
1381 }
1382 }
1383
1384 static void
client_process_output(fd_set * writeset)1385 client_process_output(fd_set *writeset)
1386 {
1387 int len;
1388 char buf[100];
1389
1390 /* Write buffered output to stdout. */
1391 if (FD_ISSET(fileno(stdout), writeset)) {
1392 /* Write as much data as possible. */
1393 len = write(fileno(stdout), buffer_ptr(&stdout_buffer),
1394 buffer_len(&stdout_buffer));
1395 if (len <= 0) {
1396 if (errno == EINTR || errno == EAGAIN ||
1397 errno == EWOULDBLOCK)
1398 len = 0;
1399 else {
1400 /*
1401 * An error or EOF was encountered. Put an
1402 * error message to stderr buffer.
1403 */
1404 snprintf(buf, sizeof buf,
1405 "write stdout: %.50s\r\n", strerror(errno));
1406 buffer_append(&stderr_buffer, buf, strlen(buf));
1407 quit_pending = 1;
1408 return;
1409 }
1410 }
1411 /* Consume printed data from the buffer. */
1412 buffer_consume(&stdout_buffer, len);
1413 }
1414 /* Write buffered output to stderr. */
1415 if (FD_ISSET(fileno(stderr), writeset)) {
1416 /* Write as much data as possible. */
1417 len = write(fileno(stderr), buffer_ptr(&stderr_buffer),
1418 buffer_len(&stderr_buffer));
1419 if (len <= 0) {
1420 if (errno == EINTR || errno == EAGAIN ||
1421 errno == EWOULDBLOCK)
1422 len = 0;
1423 else {
1424 /*
1425 * EOF or error, but can't even print
1426 * error message.
1427 */
1428 quit_pending = 1;
1429 return;
1430 }
1431 }
1432 /* Consume printed characters from the buffer. */
1433 buffer_consume(&stderr_buffer, len);
1434 }
1435 }
1436
1437 /*
1438 * Get packets from the connection input buffer, and process them as long as
1439 * there are packets available.
1440 *
1441 * Any unknown packets received during the actual
1442 * session cause the session to terminate. This is
1443 * intended to make debugging easier since no
1444 * confirmations are sent. Any compatible protocol
1445 * extensions must be negotiated during the
1446 * preparatory phase.
1447 */
1448
1449 static void
client_process_buffered_input_packets(void)1450 client_process_buffered_input_packets(void)
1451 {
1452 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, active_state);
1453 }
1454
1455 /* scan buf[] for '~' before sending data to the peer */
1456
1457 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */
1458 void *
client_new_escape_filter_ctx(int escape_char)1459 client_new_escape_filter_ctx(int escape_char)
1460 {
1461 struct escape_filter_ctx *ret;
1462
1463 ret = xcalloc(1, sizeof(*ret));
1464 ret->escape_pending = 0;
1465 ret->escape_char = escape_char;
1466 return (void *)ret;
1467 }
1468
1469 /* Free the escape filter context on channel free */
1470 void
client_filter_cleanup(int cid,void * ctx)1471 client_filter_cleanup(int cid, void *ctx)
1472 {
1473 free(ctx);
1474 }
1475
1476 int
client_simple_escape_filter(Channel * c,char * buf,int len)1477 client_simple_escape_filter(Channel *c, char *buf, int len)
1478 {
1479 if (c->extended_usage != CHAN_EXTENDED_WRITE)
1480 return 0;
1481
1482 return process_escapes(c, &c->input, &c->output, &c->extended,
1483 buf, len);
1484 }
1485
1486 static void
client_channel_closed(int id,void * arg)1487 client_channel_closed(int id, void *arg)
1488 {
1489 channel_cancel_cleanup(id);
1490 session_closed = 1;
1491 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1492 }
1493
1494 /*
1495 * Implements the interactive session with the server. This is called after
1496 * the user has been authenticated, and a command has been started on the
1497 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1498 * used as an escape character for terminating or suspending the session.
1499 */
1500
1501 int
client_loop(int have_pty,int escape_char_arg,int ssh2_chan_id)1502 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
1503 {
1504 fd_set *readset = NULL, *writeset = NULL;
1505 double start_time, total_time;
1506 int r, max_fd = 0, max_fd2 = 0, len;
1507 u_int64_t ibytes, obytes;
1508 u_int nalloc = 0;
1509 char buf[100];
1510
1511 debug("Entering interactive session.");
1512
1513 if (options.control_master &&
1514 !option_clear_or_none(options.control_path)) {
1515 debug("pledge: id");
1516 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty",
1517 NULL) == -1)
1518 fatal("%s pledge(): %s", __func__, strerror(errno));
1519
1520 } else if (options.forward_x11 || options.permit_local_command) {
1521 debug("pledge: exec");
1522 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty",
1523 NULL) == -1)
1524 fatal("%s pledge(): %s", __func__, strerror(errno));
1525
1526 } else if (options.update_hostkeys) {
1527 debug("pledge: filesystem full");
1528 if (pledge("stdio rpath wpath cpath unix inet dns proc tty",
1529 NULL) == -1)
1530 fatal("%s pledge(): %s", __func__, strerror(errno));
1531
1532 } else if (!option_clear_or_none(options.proxy_command) ||
1533 fork_after_authentication_flag) {
1534 debug("pledge: proc");
1535 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1)
1536 fatal("%s pledge(): %s", __func__, strerror(errno));
1537
1538 } else {
1539 debug("pledge: network");
1540 if (pledge("stdio unix inet dns tty", NULL) == -1)
1541 fatal("%s pledge(): %s", __func__, strerror(errno));
1542 }
1543
1544 start_time = get_current_time();
1545
1546 /* Initialize variables. */
1547 escape_pending1 = 0;
1548 last_was_cr = 1;
1549 exit_status = -1;
1550 stdin_eof = 0;
1551 buffer_high = 64 * 1024;
1552 connection_in = packet_get_connection_in();
1553 connection_out = packet_get_connection_out();
1554 max_fd = MAXIMUM(connection_in, connection_out);
1555
1556 if (!compat20) {
1557 /* enable nonblocking unless tty */
1558 if (!isatty(fileno(stdin)))
1559 set_nonblock(fileno(stdin));
1560 if (!isatty(fileno(stdout)))
1561 set_nonblock(fileno(stdout));
1562 if (!isatty(fileno(stderr)))
1563 set_nonblock(fileno(stderr));
1564 max_fd = MAXIMUM(max_fd, fileno(stdin));
1565 max_fd = MAXIMUM(max_fd, fileno(stdout));
1566 max_fd = MAXIMUM(max_fd, fileno(stderr));
1567 }
1568 quit_pending = 0;
1569 escape_char1 = escape_char_arg;
1570
1571 /* Initialize buffers. */
1572 buffer_init(&stdin_buffer);
1573 buffer_init(&stdout_buffer);
1574 buffer_init(&stderr_buffer);
1575
1576 client_init_dispatch();
1577
1578 /*
1579 * Set signal handlers, (e.g. to restore non-blocking mode)
1580 * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1581 */
1582 if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
1583 signal(SIGHUP, signal_handler);
1584 if (signal(SIGINT, SIG_IGN) != SIG_IGN)
1585 signal(SIGINT, signal_handler);
1586 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1587 signal(SIGQUIT, signal_handler);
1588 if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
1589 signal(SIGTERM, signal_handler);
1590 signal(SIGWINCH, window_change_handler);
1591
1592 if (have_pty)
1593 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1594
1595 if (compat20) {
1596 session_ident = ssh2_chan_id;
1597 if (session_ident != -1) {
1598 if (escape_char_arg != SSH_ESCAPECHAR_NONE) {
1599 channel_register_filter(session_ident,
1600 client_simple_escape_filter, NULL,
1601 client_filter_cleanup,
1602 client_new_escape_filter_ctx(
1603 escape_char_arg));
1604 }
1605 channel_register_cleanup(session_ident,
1606 client_channel_closed, 0);
1607 }
1608 } else {
1609 /* Check if we should immediately send eof on stdin. */
1610 client_check_initial_eof_on_stdin();
1611 }
1612
1613 /* Main loop of the client for the interactive session mode. */
1614 while (!quit_pending) {
1615
1616 /* Process buffered packets sent by the server. */
1617 client_process_buffered_input_packets();
1618
1619 if (compat20 && session_closed && !channel_still_open())
1620 break;
1621
1622 if (ssh_packet_is_rekeying(active_state)) {
1623 debug("rekeying in progress");
1624 } else if (need_rekeying) {
1625 /* manual rekey request */
1626 debug("need rekeying");
1627 if ((r = kex_start_rekex(active_state)) != 0)
1628 fatal("%s: kex_start_rekex: %s", __func__,
1629 ssh_err(r));
1630 need_rekeying = 0;
1631 } else {
1632 /*
1633 * Make packets of buffered stdin data, and buffer
1634 * them for sending to the server.
1635 */
1636 if (!compat20)
1637 client_make_packets_from_stdin_data();
1638
1639 /*
1640 * Make packets from buffered channel data, and
1641 * enqueue them for sending to the server.
1642 */
1643 if (packet_not_very_much_data_to_write())
1644 channel_output_poll();
1645
1646 /*
1647 * Check if the window size has changed, and buffer a
1648 * message about it to the server if so.
1649 */
1650 client_check_window_change();
1651
1652 if (quit_pending)
1653 break;
1654 }
1655 /*
1656 * Wait until we have something to do (something becomes
1657 * available on one of the descriptors).
1658 */
1659 max_fd2 = max_fd;
1660 client_wait_until_can_do_something(&readset, &writeset,
1661 &max_fd2, &nalloc, ssh_packet_is_rekeying(active_state));
1662
1663 if (quit_pending)
1664 break;
1665
1666 /* Do channel operations unless rekeying in progress. */
1667 if (!ssh_packet_is_rekeying(active_state))
1668 channel_after_select(readset, writeset);
1669
1670 /* Buffer input from the connection. */
1671 client_process_net_input(readset);
1672
1673 if (quit_pending)
1674 break;
1675
1676 if (!compat20) {
1677 /* Buffer data from stdin */
1678 client_process_input(readset);
1679 /*
1680 * Process output to stdout and stderr. Output to
1681 * the connection is processed elsewhere (above).
1682 */
1683 client_process_output(writeset);
1684 }
1685
1686 /*
1687 * Send as much buffered packet data as possible to the
1688 * sender.
1689 */
1690 if (FD_ISSET(connection_out, writeset))
1691 packet_write_poll();
1692
1693 /*
1694 * If we are a backgrounded control master, and the
1695 * timeout has expired without any active client
1696 * connections, then quit.
1697 */
1698 if (control_persist_exit_time > 0) {
1699 if (monotime() >= control_persist_exit_time) {
1700 debug("ControlPersist timeout expired");
1701 break;
1702 }
1703 }
1704 }
1705 free(readset);
1706 free(writeset);
1707
1708 /* Terminate the session. */
1709
1710 /* Stop watching for window change. */
1711 signal(SIGWINCH, SIG_DFL);
1712
1713 if (compat20) {
1714 packet_start(SSH2_MSG_DISCONNECT);
1715 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION);
1716 packet_put_cstring("disconnected by user");
1717 packet_put_cstring(""); /* language tag */
1718 packet_send();
1719 packet_write_wait();
1720 }
1721
1722 channel_free_all();
1723
1724 if (have_pty)
1725 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1726
1727 /* restore blocking io */
1728 if (!isatty(fileno(stdin)))
1729 unset_nonblock(fileno(stdin));
1730 if (!isatty(fileno(stdout)))
1731 unset_nonblock(fileno(stdout));
1732 if (!isatty(fileno(stderr)))
1733 unset_nonblock(fileno(stderr));
1734
1735 /*
1736 * If there was no shell or command requested, there will be no remote
1737 * exit status to be returned. In that case, clear error code if the
1738 * connection was deliberately terminated at this end.
1739 */
1740 if (no_shell_flag && received_signal == SIGTERM) {
1741 received_signal = 0;
1742 exit_status = 0;
1743 }
1744
1745 if (received_signal)
1746 fatal("Killed by signal %d.", (int) received_signal);
1747
1748 /*
1749 * In interactive mode (with pseudo tty) display a message indicating
1750 * that the connection has been closed.
1751 */
1752 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) {
1753 snprintf(buf, sizeof buf,
1754 "Connection to %.64s closed.\r\n", host);
1755 buffer_append(&stderr_buffer, buf, strlen(buf));
1756 }
1757
1758 /* Output any buffered data for stdout. */
1759 if (buffer_len(&stdout_buffer) > 0) {
1760 len = atomicio(vwrite, fileno(stdout),
1761 buffer_ptr(&stdout_buffer), buffer_len(&stdout_buffer));
1762 if (len < 0 || (u_int)len != buffer_len(&stdout_buffer))
1763 error("Write failed flushing stdout buffer.");
1764 else
1765 buffer_consume(&stdout_buffer, len);
1766 }
1767
1768 /* Output any buffered data for stderr. */
1769 if (buffer_len(&stderr_buffer) > 0) {
1770 len = atomicio(vwrite, fileno(stderr),
1771 buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer));
1772 if (len < 0 || (u_int)len != buffer_len(&stderr_buffer))
1773 error("Write failed flushing stderr buffer.");
1774 else
1775 buffer_consume(&stderr_buffer, len);
1776 }
1777
1778 /* Clear and free any buffers. */
1779 explicit_bzero(buf, sizeof(buf));
1780 buffer_free(&stdin_buffer);
1781 buffer_free(&stdout_buffer);
1782 buffer_free(&stderr_buffer);
1783
1784 /* Report bytes transferred, and transfer rates. */
1785 total_time = get_current_time() - start_time;
1786 packet_get_bytes(&ibytes, &obytes);
1787 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds",
1788 (unsigned long long)obytes, (unsigned long long)ibytes, total_time);
1789 if (total_time > 0)
1790 verbose("Bytes per second: sent %.1f, received %.1f",
1791 obytes / total_time, ibytes / total_time);
1792 /* Return the exit status of the program. */
1793 debug("Exit status %d", exit_status);
1794 return exit_status;
1795 }
1796
1797 /*********/
1798
1799 static int
client_input_stdout_data(int type,u_int32_t seq,void * ctxt)1800 client_input_stdout_data(int type, u_int32_t seq, void *ctxt)
1801 {
1802 u_int data_len;
1803 char *data = packet_get_string(&data_len);
1804 packet_check_eom();
1805 buffer_append(&stdout_buffer, data, data_len);
1806 explicit_bzero(data, data_len);
1807 free(data);
1808 return 0;
1809 }
1810 static int
client_input_stderr_data(int type,u_int32_t seq,void * ctxt)1811 client_input_stderr_data(int type, u_int32_t seq, void *ctxt)
1812 {
1813 u_int data_len;
1814 char *data = packet_get_string(&data_len);
1815 packet_check_eom();
1816 buffer_append(&stderr_buffer, data, data_len);
1817 explicit_bzero(data, data_len);
1818 free(data);
1819 return 0;
1820 }
1821 static int
client_input_exit_status(int type,u_int32_t seq,void * ctxt)1822 client_input_exit_status(int type, u_int32_t seq, void *ctxt)
1823 {
1824 exit_status = packet_get_int();
1825 packet_check_eom();
1826 /* Acknowledge the exit. */
1827 packet_start(SSH_CMSG_EXIT_CONFIRMATION);
1828 packet_send();
1829 /*
1830 * Must wait for packet to be sent since we are
1831 * exiting the loop.
1832 */
1833 packet_write_wait();
1834 /* Flag that we want to exit. */
1835 quit_pending = 1;
1836 return 0;
1837 }
1838
1839 static int
client_input_agent_open(int type,u_int32_t seq,void * ctxt)1840 client_input_agent_open(int type, u_int32_t seq, void *ctxt)
1841 {
1842 Channel *c = NULL;
1843 int r, remote_id, sock;
1844
1845 /* Read the remote channel number from the message. */
1846 remote_id = packet_get_int();
1847 packet_check_eom();
1848
1849 /*
1850 * Get a connection to the local authentication agent (this may again
1851 * get forwarded).
1852 */
1853 if ((r = ssh_get_authentication_socket(&sock)) != 0 &&
1854 r != SSH_ERR_AGENT_NOT_PRESENT)
1855 debug("%s: ssh_get_authentication_socket: %s",
1856 __func__, ssh_err(r));
1857
1858
1859 /*
1860 * If we could not connect the agent, send an error message back to
1861 * the server. This should never happen unless the agent dies,
1862 * because authentication forwarding is only enabled if we have an
1863 * agent.
1864 */
1865 if (sock >= 0) {
1866 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
1867 -1, 0, 0, 0, "authentication agent connection", 1);
1868 c->remote_id = remote_id;
1869 c->force_drain = 1;
1870 }
1871 if (c == NULL) {
1872 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1873 packet_put_int(remote_id);
1874 } else {
1875 /* Send a confirmation to the remote host. */
1876 debug("Forwarding authentication connection.");
1877 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1878 packet_put_int(remote_id);
1879 packet_put_int(c->self);
1880 }
1881 packet_send();
1882 return 0;
1883 }
1884
1885 static Channel *
client_request_forwarded_tcpip(const char * request_type,int rchan,u_int rwindow,u_int rmaxpack)1886 client_request_forwarded_tcpip(const char *request_type, int rchan,
1887 u_int rwindow, u_int rmaxpack)
1888 {
1889 Channel *c = NULL;
1890 struct sshbuf *b = NULL;
1891 char *listen_address, *originator_address;
1892 u_short listen_port, originator_port;
1893 int r;
1894
1895 /* Get rest of the packet */
1896 listen_address = packet_get_string(NULL);
1897 listen_port = packet_get_int();
1898 originator_address = packet_get_string(NULL);
1899 originator_port = packet_get_int();
1900 packet_check_eom();
1901
1902 debug("%s: listen %s port %d, originator %s port %d", __func__,
1903 listen_address, listen_port, originator_address, originator_port);
1904
1905 c = channel_connect_by_listen_address(listen_address, listen_port,
1906 "forwarded-tcpip", originator_address);
1907
1908 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
1909 if ((b = sshbuf_new()) == NULL) {
1910 error("%s: alloc reply", __func__);
1911 goto out;
1912 }
1913 /* reconstruct and send to muxclient */
1914 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */
1915 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
1916 (r = sshbuf_put_cstring(b, request_type)) != 0 ||
1917 (r = sshbuf_put_u32(b, rchan)) != 0 ||
1918 (r = sshbuf_put_u32(b, rwindow)) != 0 ||
1919 (r = sshbuf_put_u32(b, rmaxpack)) != 0 ||
1920 (r = sshbuf_put_cstring(b, listen_address)) != 0 ||
1921 (r = sshbuf_put_u32(b, listen_port)) != 0 ||
1922 (r = sshbuf_put_cstring(b, originator_address)) != 0 ||
1923 (r = sshbuf_put_u32(b, originator_port)) != 0 ||
1924 (r = sshbuf_put_stringb(&c->output, b)) != 0) {
1925 error("%s: compose for muxclient %s", __func__,
1926 ssh_err(r));
1927 goto out;
1928 }
1929 }
1930
1931 out:
1932 sshbuf_free(b);
1933 free(originator_address);
1934 free(listen_address);
1935 return c;
1936 }
1937
1938 static Channel *
client_request_forwarded_streamlocal(const char * request_type,int rchan)1939 client_request_forwarded_streamlocal(const char *request_type, int rchan)
1940 {
1941 Channel *c = NULL;
1942 char *listen_path;
1943
1944 /* Get the remote path. */
1945 listen_path = packet_get_string(NULL);
1946 /* XXX: Skip reserved field for now. */
1947 if (packet_get_string_ptr(NULL) == NULL)
1948 fatal("%s: packet_get_string_ptr failed", __func__);
1949 packet_check_eom();
1950
1951 debug("%s: %s", __func__, listen_path);
1952
1953 c = channel_connect_by_listen_path(listen_path,
1954 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal");
1955 free(listen_path);
1956 return c;
1957 }
1958
1959 static Channel *
client_request_x11(const char * request_type,int rchan)1960 client_request_x11(const char *request_type, int rchan)
1961 {
1962 Channel *c = NULL;
1963 char *originator;
1964 u_short originator_port;
1965 int sock;
1966
1967 if (!options.forward_x11) {
1968 error("Warning: ssh server tried X11 forwarding.");
1969 error("Warning: this is probably a break-in attempt by a "
1970 "malicious server.");
1971 return NULL;
1972 }
1973 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) {
1974 verbose("Rejected X11 connection after ForwardX11Timeout "
1975 "expired");
1976 return NULL;
1977 }
1978 originator = packet_get_string(NULL);
1979 if (datafellows & SSH_BUG_X11FWD) {
1980 debug2("buggy server: x11 request w/o originator_port");
1981 originator_port = 0;
1982 } else {
1983 originator_port = packet_get_int();
1984 }
1985 packet_check_eom();
1986 /* XXX check permission */
1987 debug("client_request_x11: request from %s %d", originator,
1988 originator_port);
1989 free(originator);
1990 sock = x11_connect_display();
1991 if (sock < 0)
1992 return NULL;
1993 c = channel_new("x11",
1994 SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1995 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1996 c->force_drain = 1;
1997 return c;
1998 }
1999
2000 static Channel *
client_request_agent(const char * request_type,int rchan)2001 client_request_agent(const char *request_type, int rchan)
2002 {
2003 Channel *c = NULL;
2004 int r, sock;
2005
2006 if (!options.forward_agent) {
2007 error("Warning: ssh server tried agent forwarding.");
2008 error("Warning: this is probably a break-in attempt by a "
2009 "malicious server.");
2010 return NULL;
2011 }
2012 if ((r = ssh_get_authentication_socket(&sock)) != 0) {
2013 if (r != SSH_ERR_AGENT_NOT_PRESENT)
2014 debug("%s: ssh_get_authentication_socket: %s",
2015 __func__, ssh_err(r));
2016 return NULL;
2017 }
2018 c = channel_new("authentication agent connection",
2019 SSH_CHANNEL_OPEN, sock, sock, -1,
2020 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
2021 "authentication agent connection", 1);
2022 c->force_drain = 1;
2023 return c;
2024 }
2025
2026 int
client_request_tun_fwd(int tun_mode,int local_tun,int remote_tun)2027 client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun)
2028 {
2029 Channel *c;
2030 int fd;
2031
2032 if (tun_mode == SSH_TUNMODE_NO)
2033 return 0;
2034
2035 if (!compat20) {
2036 error("Tunnel forwarding is not supported for protocol 1");
2037 return -1;
2038 }
2039
2040 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode);
2041
2042 /* Open local tunnel device */
2043 if ((fd = tun_open(local_tun, tun_mode)) == -1) {
2044 error("Tunnel device open failed.");
2045 return -1;
2046 }
2047
2048 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1,
2049 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
2050 c->datagram = 1;
2051
2052 #if defined(SSH_TUN_FILTER)
2053 if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
2054 channel_register_filter(c->self, sys_tun_infilter,
2055 sys_tun_outfilter, NULL, NULL);
2056 #endif
2057
2058 packet_start(SSH2_MSG_CHANNEL_OPEN);
2059 packet_put_cstring("tun@openssh.com");
2060 packet_put_int(c->self);
2061 packet_put_int(c->local_window_max);
2062 packet_put_int(c->local_maxpacket);
2063 packet_put_int(tun_mode);
2064 packet_put_int(remote_tun);
2065 packet_send();
2066
2067 return 0;
2068 }
2069
2070 /* XXXX move to generic input handler */
2071 static int
client_input_channel_open(int type,u_int32_t seq,void * ctxt)2072 client_input_channel_open(int type, u_int32_t seq, void *ctxt)
2073 {
2074 Channel *c = NULL;
2075 char *ctype;
2076 int rchan;
2077 u_int rmaxpack, rwindow, len;
2078
2079 ctype = packet_get_string(&len);
2080 rchan = packet_get_int();
2081 rwindow = packet_get_int();
2082 rmaxpack = packet_get_int();
2083
2084 debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
2085 ctype, rchan, rwindow, rmaxpack);
2086
2087 if (strcmp(ctype, "forwarded-tcpip") == 0) {
2088 c = client_request_forwarded_tcpip(ctype, rchan, rwindow,
2089 rmaxpack);
2090 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) {
2091 c = client_request_forwarded_streamlocal(ctype, rchan);
2092 } else if (strcmp(ctype, "x11") == 0) {
2093 c = client_request_x11(ctype, rchan);
2094 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
2095 c = client_request_agent(ctype, rchan);
2096 }
2097 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
2098 debug3("proxied to downstream: %s", ctype);
2099 } else if (c != NULL) {
2100 debug("confirm %s", ctype);
2101 c->remote_id = rchan;
2102 c->remote_window = rwindow;
2103 c->remote_maxpacket = rmaxpack;
2104 if (c->type != SSH_CHANNEL_CONNECTING) {
2105 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
2106 packet_put_int(c->remote_id);
2107 packet_put_int(c->self);
2108 packet_put_int(c->local_window);
2109 packet_put_int(c->local_maxpacket);
2110 packet_send();
2111 }
2112 } else {
2113 debug("failure %s", ctype);
2114 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
2115 packet_put_int(rchan);
2116 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED);
2117 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2118 packet_put_cstring("open failed");
2119 packet_put_cstring("");
2120 }
2121 packet_send();
2122 }
2123 free(ctype);
2124 return 0;
2125 }
2126
2127 static int
client_input_channel_req(int type,u_int32_t seq,void * ctxt)2128 client_input_channel_req(int type, u_int32_t seq, void *ctxt)
2129 {
2130 Channel *c = NULL;
2131 int exitval, id, reply, success = 0;
2132 char *rtype;
2133
2134 id = packet_get_int();
2135 c = channel_lookup(id);
2136 if (channel_proxy_upstream(c, type, seq, ctxt))
2137 return 0;
2138 rtype = packet_get_string(NULL);
2139 reply = packet_get_char();
2140
2141 debug("client_input_channel_req: channel %d rtype %s reply %d",
2142 id, rtype, reply);
2143
2144 if (id == -1) {
2145 error("client_input_channel_req: request for channel -1");
2146 } else if (c == NULL) {
2147 error("client_input_channel_req: channel %d: "
2148 "unknown channel", id);
2149 } else if (strcmp(rtype, "eow@openssh.com") == 0) {
2150 packet_check_eom();
2151 chan_rcvd_eow(c);
2152 } else if (strcmp(rtype, "exit-status") == 0) {
2153 exitval = packet_get_int();
2154 if (c->ctl_chan != -1) {
2155 mux_exit_message(c, exitval);
2156 success = 1;
2157 } else if (id == session_ident) {
2158 /* Record exit value of local session */
2159 success = 1;
2160 exit_status = exitval;
2161 } else {
2162 /* Probably for a mux channel that has already closed */
2163 debug("%s: no sink for exit-status on channel %d",
2164 __func__, id);
2165 }
2166 packet_check_eom();
2167 }
2168 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) {
2169 packet_start(success ?
2170 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE);
2171 packet_put_int(c->remote_id);
2172 packet_send();
2173 }
2174 free(rtype);
2175 return 0;
2176 }
2177
2178 struct hostkeys_update_ctx {
2179 /* The hostname and (optionally) IP address string for the server */
2180 char *host_str, *ip_str;
2181
2182 /*
2183 * Keys received from the server and a flag for each indicating
2184 * whether they already exist in known_hosts.
2185 * keys_seen is filled in by hostkeys_find() and later (for new
2186 * keys) by client_global_hostkeys_private_confirm().
2187 */
2188 struct sshkey **keys;
2189 int *keys_seen;
2190 size_t nkeys;
2191
2192 size_t nnew;
2193
2194 /*
2195 * Keys that are in known_hosts, but were not present in the update
2196 * from the server (i.e. scheduled to be deleted).
2197 * Filled in by hostkeys_find().
2198 */
2199 struct sshkey **old_keys;
2200 size_t nold;
2201 };
2202
2203 static void
hostkeys_update_ctx_free(struct hostkeys_update_ctx * ctx)2204 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx)
2205 {
2206 size_t i;
2207
2208 if (ctx == NULL)
2209 return;
2210 for (i = 0; i < ctx->nkeys; i++)
2211 sshkey_free(ctx->keys[i]);
2212 free(ctx->keys);
2213 free(ctx->keys_seen);
2214 for (i = 0; i < ctx->nold; i++)
2215 sshkey_free(ctx->old_keys[i]);
2216 free(ctx->old_keys);
2217 free(ctx->host_str);
2218 free(ctx->ip_str);
2219 free(ctx);
2220 }
2221
2222 static int
hostkeys_find(struct hostkey_foreach_line * l,void * _ctx)2223 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx)
2224 {
2225 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
2226 size_t i;
2227 struct sshkey **tmp;
2228
2229 if (l->status != HKF_STATUS_MATCHED || l->key == NULL ||
2230 l->key->type == KEY_RSA1)
2231 return 0;
2232
2233 /* Mark off keys we've already seen for this host */
2234 for (i = 0; i < ctx->nkeys; i++) {
2235 if (sshkey_equal(l->key, ctx->keys[i])) {
2236 debug3("%s: found %s key at %s:%ld", __func__,
2237 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum);
2238 ctx->keys_seen[i] = 1;
2239 return 0;
2240 }
2241 }
2242 /* This line contained a key that not offered by the server */
2243 debug3("%s: deprecated %s key at %s:%ld", __func__,
2244 sshkey_ssh_name(l->key), l->path, l->linenum);
2245 if ((tmp = reallocarray(ctx->old_keys, ctx->nold + 1,
2246 sizeof(*ctx->old_keys))) == NULL)
2247 fatal("%s: reallocarray failed nold = %zu",
2248 __func__, ctx->nold);
2249 ctx->old_keys = tmp;
2250 ctx->old_keys[ctx->nold++] = l->key;
2251 l->key = NULL;
2252
2253 return 0;
2254 }
2255
2256 static void
update_known_hosts(struct hostkeys_update_ctx * ctx)2257 update_known_hosts(struct hostkeys_update_ctx *ctx)
2258 {
2259 int r, was_raw = 0;
2260 int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ?
2261 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE;
2262 char *fp, *response;
2263 size_t i;
2264
2265 for (i = 0; i < ctx->nkeys; i++) {
2266 if (ctx->keys_seen[i] != 2)
2267 continue;
2268 if ((fp = sshkey_fingerprint(ctx->keys[i],
2269 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
2270 fatal("%s: sshkey_fingerprint failed", __func__);
2271 do_log2(loglevel, "Learned new hostkey: %s %s",
2272 sshkey_type(ctx->keys[i]), fp);
2273 free(fp);
2274 }
2275 for (i = 0; i < ctx->nold; i++) {
2276 if ((fp = sshkey_fingerprint(ctx->old_keys[i],
2277 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
2278 fatal("%s: sshkey_fingerprint failed", __func__);
2279 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s",
2280 sshkey_type(ctx->old_keys[i]), fp);
2281 free(fp);
2282 }
2283 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
2284 if (get_saved_tio() != NULL) {
2285 leave_raw_mode(1);
2286 was_raw = 1;
2287 }
2288 response = NULL;
2289 for (i = 0; !quit_pending && i < 3; i++) {
2290 free(response);
2291 response = read_passphrase("Accept updated hostkeys? "
2292 "(yes/no): ", RP_ECHO);
2293 if (strcasecmp(response, "yes") == 0)
2294 break;
2295 else if (quit_pending || response == NULL ||
2296 strcasecmp(response, "no") == 0) {
2297 options.update_hostkeys = 0;
2298 break;
2299 } else {
2300 do_log2(loglevel, "Please enter "
2301 "\"yes\" or \"no\"");
2302 }
2303 }
2304 if (quit_pending || i >= 3 || response == NULL)
2305 options.update_hostkeys = 0;
2306 free(response);
2307 if (was_raw)
2308 enter_raw_mode(1);
2309 }
2310
2311 /*
2312 * Now that all the keys are verified, we can go ahead and replace
2313 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't
2314 * cancel the operation).
2315 */
2316 if (options.update_hostkeys != 0 &&
2317 (r = hostfile_replace_entries(options.user_hostfiles[0],
2318 ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys,
2319 options.hash_known_hosts, 0,
2320 options.fingerprint_hash)) != 0)
2321 error("%s: hostfile_replace_entries failed: %s",
2322 __func__, ssh_err(r));
2323 }
2324
2325 static void
client_global_hostkeys_private_confirm(int type,u_int32_t seq,void * _ctx)2326 client_global_hostkeys_private_confirm(int type, u_int32_t seq, void *_ctx)
2327 {
2328 struct ssh *ssh = active_state; /* XXX */
2329 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
2330 size_t i, ndone;
2331 struct sshbuf *signdata;
2332 int r;
2333 const u_char *sig;
2334 size_t siglen;
2335
2336 if (ctx->nnew == 0)
2337 fatal("%s: ctx->nnew == 0", __func__); /* sanity */
2338 if (type != SSH2_MSG_REQUEST_SUCCESS) {
2339 error("Server failed to confirm ownership of "
2340 "private host keys");
2341 hostkeys_update_ctx_free(ctx);
2342 return;
2343 }
2344 if ((signdata = sshbuf_new()) == NULL)
2345 fatal("%s: sshbuf_new failed", __func__);
2346 /* Don't want to accidentally accept an unbound signature */
2347 if (ssh->kex->session_id_len == 0)
2348 fatal("%s: ssh->kex->session_id_len == 0", __func__);
2349 /*
2350 * Expect a signature for each of the ctx->nnew private keys we
2351 * haven't seen before. They will be in the same order as the
2352 * ctx->keys where the corresponding ctx->keys_seen[i] == 0.
2353 */
2354 for (ndone = i = 0; i < ctx->nkeys; i++) {
2355 if (ctx->keys_seen[i])
2356 continue;
2357 /* Prepare data to be signed: session ID, unique string, key */
2358 sshbuf_reset(signdata);
2359 if ( (r = sshbuf_put_cstring(signdata,
2360 "hostkeys-prove-00@openssh.com")) != 0 ||
2361 (r = sshbuf_put_string(signdata, ssh->kex->session_id,
2362 ssh->kex->session_id_len)) != 0 ||
2363 (r = sshkey_puts(ctx->keys[i], signdata)) != 0)
2364 fatal("%s: failed to prepare signature: %s",
2365 __func__, ssh_err(r));
2366 /* Extract and verify signature */
2367 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) {
2368 error("%s: couldn't parse message: %s",
2369 __func__, ssh_err(r));
2370 goto out;
2371 }
2372 if ((r = sshkey_verify(ctx->keys[i], sig, siglen,
2373 sshbuf_ptr(signdata), sshbuf_len(signdata), 0)) != 0) {
2374 error("%s: server gave bad signature for %s key %zu",
2375 __func__, sshkey_type(ctx->keys[i]), i);
2376 goto out;
2377 }
2378 /* Key is good. Mark it as 'seen' */
2379 ctx->keys_seen[i] = 2;
2380 ndone++;
2381 }
2382 if (ndone != ctx->nnew)
2383 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__,
2384 ndone, ctx->nnew); /* Shouldn't happen */
2385 ssh_packet_check_eom(ssh);
2386
2387 /* Make the edits to known_hosts */
2388 update_known_hosts(ctx);
2389 out:
2390 hostkeys_update_ctx_free(ctx);
2391 }
2392
2393 /*
2394 * Returns non-zero if the key is accepted by HostkeyAlgorithms.
2395 * Made slightly less trivial by the multiple RSA signature algorithm names.
2396 */
2397 static int
key_accepted_by_hostkeyalgs(const struct sshkey * key)2398 key_accepted_by_hostkeyalgs(const struct sshkey *key)
2399 {
2400 const char *ktype = sshkey_ssh_name(key);
2401 const char *hostkeyalgs = options.hostkeyalgorithms != NULL ?
2402 options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG;
2403
2404 if (key == NULL || key->type == KEY_UNSPEC)
2405 return 0;
2406 if (key->type == KEY_RSA &&
2407 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 ||
2408 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1))
2409 return 1;
2410 return match_pattern_list(ktype, hostkeyalgs, 0) == 1;
2411 }
2412
2413 /*
2414 * Handle hostkeys-00@openssh.com global request to inform the client of all
2415 * the server's hostkeys. The keys are checked against the user's
2416 * HostkeyAlgorithms preference before they are accepted.
2417 */
2418 static int
client_input_hostkeys(void)2419 client_input_hostkeys(void)
2420 {
2421 struct ssh *ssh = active_state; /* XXX */
2422 const u_char *blob = NULL;
2423 size_t i, len = 0;
2424 struct sshbuf *buf = NULL;
2425 struct sshkey *key = NULL, **tmp;
2426 int r;
2427 char *fp;
2428 static int hostkeys_seen = 0; /* XXX use struct ssh */
2429 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */
2430 struct hostkeys_update_ctx *ctx = NULL;
2431
2432 if (hostkeys_seen)
2433 fatal("%s: server already sent hostkeys", __func__);
2434 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK &&
2435 options.batch_mode)
2436 return 1; /* won't ask in batchmode, so don't even try */
2437 if (!options.update_hostkeys || options.num_user_hostfiles <= 0)
2438 return 1;
2439
2440 ctx = xcalloc(1, sizeof(*ctx));
2441 while (ssh_packet_remaining(ssh) > 0) {
2442 sshkey_free(key);
2443 key = NULL;
2444 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) {
2445 error("%s: couldn't parse message: %s",
2446 __func__, ssh_err(r));
2447 goto out;
2448 }
2449 if ((r = sshkey_from_blob(blob, len, &key)) != 0) {
2450 error("%s: parse key: %s", __func__, ssh_err(r));
2451 goto out;
2452 }
2453 fp = sshkey_fingerprint(key, options.fingerprint_hash,
2454 SSH_FP_DEFAULT);
2455 debug3("%s: received %s key %s", __func__,
2456 sshkey_type(key), fp);
2457 free(fp);
2458
2459 if (!key_accepted_by_hostkeyalgs(key)) {
2460 debug3("%s: %s key not permitted by HostkeyAlgorithms",
2461 __func__, sshkey_ssh_name(key));
2462 continue;
2463 }
2464 /* Skip certs */
2465 if (sshkey_is_cert(key)) {
2466 debug3("%s: %s key is a certificate; skipping",
2467 __func__, sshkey_ssh_name(key));
2468 continue;
2469 }
2470 /* Ensure keys are unique */
2471 for (i = 0; i < ctx->nkeys; i++) {
2472 if (sshkey_equal(key, ctx->keys[i])) {
2473 error("%s: received duplicated %s host key",
2474 __func__, sshkey_ssh_name(key));
2475 goto out;
2476 }
2477 }
2478 /* Key is good, record it */
2479 if ((tmp = reallocarray(ctx->keys, ctx->nkeys + 1,
2480 sizeof(*ctx->keys))) == NULL)
2481 fatal("%s: reallocarray failed nkeys = %zu",
2482 __func__, ctx->nkeys);
2483 ctx->keys = tmp;
2484 ctx->keys[ctx->nkeys++] = key;
2485 key = NULL;
2486 }
2487
2488 if (ctx->nkeys == 0) {
2489 debug("%s: server sent no hostkeys", __func__);
2490 goto out;
2491 }
2492
2493 if ((ctx->keys_seen = calloc(ctx->nkeys,
2494 sizeof(*ctx->keys_seen))) == NULL)
2495 fatal("%s: calloc failed", __func__);
2496
2497 get_hostfile_hostname_ipaddr(host,
2498 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL,
2499 options.port, &ctx->host_str,
2500 options.check_host_ip ? &ctx->ip_str : NULL);
2501
2502 /* Find which keys we already know about. */
2503 if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find,
2504 ctx, ctx->host_str, ctx->ip_str,
2505 HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) {
2506 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
2507 goto out;
2508 }
2509
2510 /* Figure out if we have any new keys to add */
2511 ctx->nnew = 0;
2512 for (i = 0; i < ctx->nkeys; i++) {
2513 if (!ctx->keys_seen[i])
2514 ctx->nnew++;
2515 }
2516
2517 debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove",
2518 __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold);
2519
2520 if (ctx->nnew == 0 && ctx->nold != 0) {
2521 /* We have some keys to remove. Just do it. */
2522 update_known_hosts(ctx);
2523 } else if (ctx->nnew != 0) {
2524 /*
2525 * We have received hitherto-unseen keys from the server.
2526 * Ask the server to confirm ownership of the private halves.
2527 */
2528 debug3("%s: asking server to prove ownership for %zu keys",
2529 __func__, ctx->nnew);
2530 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2531 (r = sshpkt_put_cstring(ssh,
2532 "hostkeys-prove-00@openssh.com")) != 0 ||
2533 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */
2534 fatal("%s: cannot prepare packet: %s",
2535 __func__, ssh_err(r));
2536 if ((buf = sshbuf_new()) == NULL)
2537 fatal("%s: sshbuf_new", __func__);
2538 for (i = 0; i < ctx->nkeys; i++) {
2539 if (ctx->keys_seen[i])
2540 continue;
2541 sshbuf_reset(buf);
2542 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0)
2543 fatal("%s: sshkey_putb: %s",
2544 __func__, ssh_err(r));
2545 if ((r = sshpkt_put_stringb(ssh, buf)) != 0)
2546 fatal("%s: sshpkt_put_string: %s",
2547 __func__, ssh_err(r));
2548 }
2549 if ((r = sshpkt_send(ssh)) != 0)
2550 fatal("%s: sshpkt_send: %s", __func__, ssh_err(r));
2551 client_register_global_confirm(
2552 client_global_hostkeys_private_confirm, ctx);
2553 ctx = NULL; /* will be freed in callback */
2554 }
2555
2556 /* Success */
2557 out:
2558 hostkeys_update_ctx_free(ctx);
2559 sshkey_free(key);
2560 sshbuf_free(buf);
2561 /*
2562 * NB. Return success for all cases. The server doesn't need to know
2563 * what the client does with its hosts file.
2564 */
2565 return 1;
2566 }
2567
2568 static int
client_input_global_request(int type,u_int32_t seq,void * ctxt)2569 client_input_global_request(int type, u_int32_t seq, void *ctxt)
2570 {
2571 char *rtype;
2572 int want_reply;
2573 int success = 0;
2574
2575 rtype = packet_get_cstring(NULL);
2576 want_reply = packet_get_char();
2577 debug("client_input_global_request: rtype %s want_reply %d",
2578 rtype, want_reply);
2579 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0)
2580 success = client_input_hostkeys();
2581 if (want_reply) {
2582 packet_start(success ?
2583 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE);
2584 packet_send();
2585 packet_write_wait();
2586 }
2587 free(rtype);
2588 return 0;
2589 }
2590
2591 void
client_session2_setup(int id,int want_tty,int want_subsystem,const char * term,struct termios * tiop,int in_fd,Buffer * cmd,char ** env)2592 client_session2_setup(int id, int want_tty, int want_subsystem,
2593 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env)
2594 {
2595 int len;
2596 Channel *c = NULL;
2597
2598 debug2("%s: id %d", __func__, id);
2599
2600 if ((c = channel_lookup(id)) == NULL)
2601 fatal("client_session2_setup: channel %d: unknown channel", id);
2602
2603 packet_set_interactive(want_tty,
2604 options.ip_qos_interactive, options.ip_qos_bulk);
2605
2606 if (want_tty) {
2607 struct winsize ws;
2608
2609 /* Store window size in the packet. */
2610 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0)
2611 memset(&ws, 0, sizeof(ws));
2612
2613 channel_request_start(id, "pty-req", 1);
2614 client_expect_confirm(id, "PTY allocation", CONFIRM_TTY);
2615 packet_put_cstring(term != NULL ? term : "");
2616 packet_put_int((u_int)ws.ws_col);
2617 packet_put_int((u_int)ws.ws_row);
2618 packet_put_int((u_int)ws.ws_xpixel);
2619 packet_put_int((u_int)ws.ws_ypixel);
2620 if (tiop == NULL)
2621 tiop = get_saved_tio();
2622 tty_make_modes(-1, tiop);
2623 packet_send();
2624 /* XXX wait for reply */
2625 c->client_tty = 1;
2626 }
2627
2628 /* Transfer any environment variables from client to server */
2629 if (options.num_send_env != 0 && env != NULL) {
2630 int i, j, matched;
2631 char *name, *val;
2632
2633 debug("Sending environment.");
2634 for (i = 0; env[i] != NULL; i++) {
2635 /* Split */
2636 name = xstrdup(env[i]);
2637 if ((val = strchr(name, '=')) == NULL) {
2638 free(name);
2639 continue;
2640 }
2641 *val++ = '\0';
2642
2643 matched = 0;
2644 for (j = 0; j < options.num_send_env; j++) {
2645 if (match_pattern(name, options.send_env[j])) {
2646 matched = 1;
2647 break;
2648 }
2649 }
2650 if (!matched) {
2651 debug3("Ignored env %s", name);
2652 free(name);
2653 continue;
2654 }
2655
2656 debug("Sending env %s = %s", name, val);
2657 channel_request_start(id, "env", 0);
2658 packet_put_cstring(name);
2659 packet_put_cstring(val);
2660 packet_send();
2661 free(name);
2662 }
2663 }
2664
2665 len = buffer_len(cmd);
2666 if (len > 0) {
2667 if (len > 900)
2668 len = 900;
2669 if (want_subsystem) {
2670 debug("Sending subsystem: %.*s",
2671 len, (u_char*)buffer_ptr(cmd));
2672 channel_request_start(id, "subsystem", 1);
2673 client_expect_confirm(id, "subsystem", CONFIRM_CLOSE);
2674 } else {
2675 debug("Sending command: %.*s",
2676 len, (u_char*)buffer_ptr(cmd));
2677 channel_request_start(id, "exec", 1);
2678 client_expect_confirm(id, "exec", CONFIRM_CLOSE);
2679 }
2680 packet_put_string(buffer_ptr(cmd), buffer_len(cmd));
2681 packet_send();
2682 } else {
2683 channel_request_start(id, "shell", 1);
2684 client_expect_confirm(id, "shell", CONFIRM_CLOSE);
2685 packet_send();
2686 }
2687 }
2688
2689 static void
client_init_dispatch_20(void)2690 client_init_dispatch_20(void)
2691 {
2692 dispatch_init(&dispatch_protocol_error);
2693
2694 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
2695 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data);
2696 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
2697 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
2698 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
2699 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
2700 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
2701 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
2702 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
2703 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
2704 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
2705 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
2706
2707 /* rekeying */
2708 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
2709
2710 /* global request reply messages */
2711 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
2712 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
2713 }
2714
2715 static void
client_init_dispatch_13(void)2716 client_init_dispatch_13(void)
2717 {
2718 dispatch_init(NULL);
2719 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close);
2720 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation);
2721 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data);
2722 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
2723 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
2724 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open);
2725 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status);
2726 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data);
2727 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data);
2728
2729 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ?
2730 &client_input_agent_open : &deny_input_open);
2731 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ?
2732 &x11_input_open : &deny_input_open);
2733 }
2734
2735 static void
client_init_dispatch_15(void)2736 client_init_dispatch_15(void)
2737 {
2738 client_init_dispatch_13();
2739 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof);
2740 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose);
2741 }
2742
2743 static void
client_init_dispatch(void)2744 client_init_dispatch(void)
2745 {
2746 if (compat20)
2747 client_init_dispatch_20();
2748 else if (compat13)
2749 client_init_dispatch_13();
2750 else
2751 client_init_dispatch_15();
2752 }
2753
2754 void
client_stop_mux(void)2755 client_stop_mux(void)
2756 {
2757 if (options.control_path != NULL && muxserver_sock != -1)
2758 unlink(options.control_path);
2759 /*
2760 * If we are in persist mode, or don't have a shell, signal that we
2761 * should close when all active channels are closed.
2762 */
2763 if (options.control_persist || no_shell_flag) {
2764 session_closed = 1;
2765 setproctitle("[stopped mux]");
2766 }
2767 }
2768
2769 /* client specific fatal cleanup */
2770 void
cleanup_exit(int i)2771 cleanup_exit(int i)
2772 {
2773 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
2774 leave_non_blocking();
2775 if (options.control_path != NULL && muxserver_sock != -1)
2776 unlink(options.control_path);
2777 ssh_kill_proxy_command();
2778 _exit(i);
2779 }
2780