1 /* $OpenBSD: clientloop.c,v 1.398 2023/09/10 03:51:55 djm Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * The main loop for the interactive session (client side).
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".
15 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
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.
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.
38 * SSH2 support added by Markus Friedl.
39 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved.
41 * Redistribution and use in source and binary forms, with or without
42 * modification, are permitted provided that the following conditions
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.
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.
64 #include <sys/types.h>
65 #include <sys/ioctl.h>
66 #ifdef HAVE_SYS_STAT_H
67 # include <sys/stat.h>
69 #ifdef HAVE_SYS_TIME_H
70 # include <sys/time.h>
72 #include <sys/socket.h>
92 #include "openbsd-compat/sys-queue.h"
100 #include "dispatch.h"
104 #include "myproposal.h"
107 #include "readconf.h"
108 #include "clientloop.h"
109 #include "sshconnect.h"
111 #include "atomicio.h"
116 #include "hostfile.h"
118 /* Permitted RSA signature algorithms for UpdateHostkeys proofs */
119 #define HOSTKEY_PROOF_RSA_ALGS "rsa-sha2-512,rsa-sha2-256"
121 /* Uncertainty (in percent) of keystroke timing intervals */
122 #define SSH_KEYSTROKE_TIMING_FUZZ 10
125 extern Options options;
128 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */
131 * Name of the host we are connecting to. This is the name given on the
132 * command line, or the Hostname specified for the user-supplied name in a
133 * configuration file.
138 * If this field is not NULL, the ForwardAgent socket is this path and different
139 * instead of SSH_AUTH_SOCK.
141 extern char *forward_agent_sock_path;
144 * Flag to indicate that we have received a window change signal which has
145 * not yet been processed. This will cause a message indicating the new
146 * window size to be sent to the server a little later. This is volatile
147 * because this is updated in a signal handler.
149 static volatile sig_atomic_t received_window_change_signal = 0;
150 static volatile sig_atomic_t received_signal = 0;
152 /* Time when backgrounded control master using ControlPersist should exit */
153 static time_t control_persist_exit_time = 0;
155 /* Common data for the client loop code. */
156 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
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 struct sshbuf *stderr_buffer; /* Used for final exit message. */
160 static int connection_in; /* Connection to server (input). */
161 static int connection_out; /* Connection to server (output). */
162 static int need_rekeying; /* Set to non-zero if rekeying is requested. */
163 static int session_closed; /* In SSH2: login session closed. */
164 static time_t x11_refuse_time; /* If >0, refuse x11 opens after this time. */
165 static time_t server_alive_time; /* Time to do server_alive_check */
166 static int hostkeys_update_complete;
167 static int session_setup_complete;
169 static void client_init_dispatch(struct ssh *ssh);
170 int session_ident = -1;
172 /* Track escape per proto2 channel */
173 struct escape_filter_ctx {
178 /* Context for channel confirmation replies */
179 struct channel_reply_ctx {
180 const char *request_type;
182 enum confirm_action action;
185 /* Global request success/failure callbacks */
186 /* XXX move to struct ssh? */
187 struct global_confirm {
188 TAILQ_ENTRY(global_confirm) entry;
189 global_confirm_cb *cb;
193 TAILQ_HEAD(global_confirms, global_confirm);
194 static struct global_confirms global_confirms =
195 TAILQ_HEAD_INITIALIZER(global_confirms);
197 void ssh_process_session2_setup(int, int, int, struct sshbuf *);
198 static void quit_message(const char *fmt, ...)
199 __attribute__((__format__ (printf, 1, 2)));
202 quit_message(const char *fmt, ...)
209 xvasprintf(&msg, fmt, args);
212 if ((r = sshbuf_putf(stderr_buffer, "%s\r\n", msg)) != 0)
213 fatal_fr(r, "sshbuf_putf");
218 * Signal handler for the window change signal (SIGWINCH). This just sets a
219 * flag indicating that the window has changed.
222 window_change_handler(int sig)
224 received_window_change_signal = 1;
228 * Signal handler for signals that cause the program to terminate. These
229 * signals must be trapped to restore terminal modes.
232 signal_handler(int sig)
234 received_signal = sig;
239 * Sets control_persist_exit_time to the absolute time when the
240 * backgrounded control master should exit due to expiry of the
241 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded
242 * control master process, or if there is no ControlPersist timeout.
245 set_control_persist_exit_time(struct ssh *ssh)
247 if (muxserver_sock == -1 || !options.control_persist
248 || options.control_persist_timeout == 0) {
249 /* not using a ControlPersist timeout */
250 control_persist_exit_time = 0;
251 } else if (channel_still_open(ssh)) {
252 /* some client connections are still open */
253 if (control_persist_exit_time > 0)
254 debug2_f("cancel scheduled exit");
255 control_persist_exit_time = 0;
256 } else if (control_persist_exit_time <= 0) {
257 /* a client connection has recently closed */
258 control_persist_exit_time = monotime() +
259 (time_t)options.control_persist_timeout;
260 debug2_f("schedule exit in %d seconds",
261 options.control_persist_timeout);
263 /* else we are already counting down to the timeout */
266 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_"
268 client_x11_display_valid(const char *display)
275 dlen = strlen(display);
276 for (i = 0; i < dlen; i++) {
277 if (!isalnum((u_char)display[i]) &&
278 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) {
279 debug("Invalid character '%c' in DISPLAY", display[i]);
286 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
287 #define X11_TIMEOUT_SLACK 60
289 client_x11_get_proto(struct ssh *ssh, const char *display,
290 const char *xauth_path, u_int trusted, u_int timeout,
291 char **_proto, char **_data)
293 char *cmd, line[512], xdisplay[512];
294 char xauthfile[PATH_MAX], xauthdir[PATH_MAX];
295 static char proto[512], data[512];
297 int got_data = 0, generated = 0, do_unlink = 0, r;
299 u_int now, x11_timeout_real;
303 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0';
305 if (!client_x11_display_valid(display)) {
307 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding",
311 if (xauth_path != NULL && stat(xauth_path, &st) == -1) {
312 debug("No xauth program.");
316 if (xauth_path != NULL) {
318 * Handle FamilyLocal case where $DISPLAY does
319 * not match an authorization entry. For this we
320 * just try "xauth list unix:displaynum.screennum".
321 * XXX: "localhost" match to determine FamilyLocal
324 if (strncmp(display, "localhost:", 10) == 0) {
325 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
326 display + 10)) < 0 ||
327 (size_t)r >= sizeof(xdisplay)) {
328 error_f("display name too long");
335 * Generate an untrusted X11 auth cookie.
337 * The authentication cookie should briefly outlive
338 * ssh's willingness to forward X11 connections to
339 * avoid nasty fail-open behaviour in the X server.
341 mktemp_proto(xauthdir, sizeof(xauthdir));
342 if (mkdtemp(xauthdir) == NULL) {
343 error_f("mkdtemp: %s", strerror(errno));
347 if ((r = snprintf(xauthfile, sizeof(xauthfile),
348 "%s/xauthfile", xauthdir)) < 0 ||
349 (size_t)r >= sizeof(xauthfile)) {
350 error_f("xauthfile path too long");
356 /* auth doesn't time out */
357 xasprintf(&cmd, "%s -f %s generate %s %s "
359 xauth_path, xauthfile, display,
360 SSH_X11_PROTO, _PATH_DEVNULL);
362 /* Add some slack to requested expiry */
363 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK)
364 x11_timeout_real = timeout +
367 /* Don't overflow on long timeouts */
368 x11_timeout_real = UINT_MAX;
370 xasprintf(&cmd, "%s -f %s generate %s %s "
371 "untrusted timeout %u 2>%s",
372 xauth_path, xauthfile, display,
373 SSH_X11_PROTO, x11_timeout_real,
376 debug2_f("xauth command: %s", cmd);
378 if (timeout != 0 && x11_refuse_time == 0) {
379 now = monotime() + 1;
380 if (SSH_TIME_T_MAX - timeout < now)
381 x11_refuse_time = SSH_TIME_T_MAX;
383 x11_refuse_time = now + timeout;
384 channel_set_x11_refuse_time(ssh,
387 if (system(cmd) == 0)
393 * When in untrusted mode, we read the cookie only if it was
394 * successfully generated as an untrusted one in the step
397 if (trusted || generated) {
399 "%s %s%s list %s 2>" _PATH_DEVNULL,
401 generated ? "-f " : "" ,
402 generated ? xauthfile : "",
404 debug2("x11_get_proto: %s", cmd);
406 if (f && fgets(line, sizeof(line), f) &&
407 sscanf(line, "%*s %511s %511s", proto, data) == 2)
420 /* Don't fall back to fake X11 data for untrusted forwarding */
421 if (!trusted && !got_data) {
422 error("Warning: untrusted X11 forwarding setup failed: "
423 "xauth key data not generated");
428 * If we didn't get authentication data, just make up some
429 * data. The forwarding code will check the validity of the
430 * response anyway, and substitute this data. The X11
431 * server, however, will ignore this fake data and use
432 * whatever authentication mechanisms it was using otherwise
433 * for the local connection.
439 logit("Warning: No xauth data; "
440 "using fake authentication data for X11 forwarding.");
441 strlcpy(proto, SSH_X11_PROTO, sizeof proto);
442 arc4random_buf(rnd, sizeof(rnd));
443 for (i = 0; i < sizeof(rnd); i++) {
444 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
453 * Checks if the client window has changed, and sends a packet about it to
454 * the server if so. The actual change is detected elsewhere (by a software
455 * interrupt on Unix); this just checks the flag and sends a message if
460 client_check_window_change(struct ssh *ssh)
462 if (!received_window_change_signal)
464 received_window_change_signal = 0;
466 channel_send_window_changes(ssh);
470 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh)
472 struct global_confirm *gc;
474 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL)
477 gc->cb(ssh, type, seq, gc->ctx);
478 if (--gc->ref_count <= 0) {
479 TAILQ_REMOVE(&global_confirms, gc, entry);
480 freezero(gc, sizeof(*gc));
483 ssh_packet_set_alive_timeouts(ssh, 0);
488 schedule_server_alive_check(void)
490 if (options.server_alive_interval > 0)
491 server_alive_time = monotime() + options.server_alive_interval;
495 server_alive_check(struct ssh *ssh)
499 if (ssh_packet_inc_alive_timeouts(ssh) > options.server_alive_count_max) {
500 logit("Timeout, server %s not responding.", host);
503 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
504 (r = sshpkt_put_cstring(ssh, "keepalive@openssh.com")) != 0 ||
505 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* boolean: want reply */
506 (r = sshpkt_send(ssh)) != 0)
507 fatal_fr(r, "send packet");
508 /* Insert an empty placeholder to maintain ordering */
509 client_register_global_confirm(NULL, NULL);
510 schedule_server_alive_check();
513 /* Try to send a dummy keystroke */
515 send_chaff(struct ssh *ssh)
519 if ((ssh->kex->flags & KEX_HAS_PING) == 0)
521 /* XXX probabilistically send chaff? */
523 * a SSH2_MSG_CHANNEL_DATA payload is 9 bytes:
524 * 4 bytes channel ID + 4 bytes string length + 1 byte string data
525 * simulate that here.
527 if ((r = sshpkt_start(ssh, SSH2_MSG_PING)) != 0 ||
528 (r = sshpkt_put_cstring(ssh, "PING!")) != 0 ||
529 (r = sshpkt_send(ssh)) != 0)
530 fatal_fr(r, "send packet");
534 /* Sets the next interval to send a keystroke or chaff packet */
536 set_next_interval(const struct timespec *now, struct timespec *next_interval,
537 u_int interval_ms, int starting)
540 long long interval_ns, fuzz_ns;
541 static long long rate_fuzz;
543 interval_ns = interval_ms * (1000LL * 1000);
544 fuzz_ns = (interval_ns * SSH_KEYSTROKE_TIMING_FUZZ) / 100;
545 /* Center fuzz around requested interval */
546 if (fuzz_ns > INT_MAX)
548 if (fuzz_ns > interval_ns) {
549 /* Shouldn't happen */
550 fatal_f("internal error: fuzz %u%% %lldns > interval %lldns",
551 SSH_KEYSTROKE_TIMING_FUZZ, fuzz_ns, interval_ns);
554 * Randomise the keystroke/chaff intervals in two ways:
555 * 1. Each interval has some random jitter applied to make the
556 * interval-to-interval time unpredictable.
557 * 2. The overall interval rate is also randomly perturbed for each
558 * chaffing session to make the average rate unpredictable.
561 rate_fuzz = arc4random_uniform(fuzz_ns);
562 interval_ns -= fuzz_ns;
563 interval_ns += arc4random_uniform(fuzz_ns) + rate_fuzz;
565 tmp.tv_sec = interval_ns / (1000 * 1000 * 1000);
566 tmp.tv_nsec = interval_ns % (1000 * 1000 * 1000);
568 timespecadd(now, &tmp, next_interval);
572 * Performs keystroke timing obfuscation. Returns non-zero if the
573 * output fd should be polled.
576 obfuscate_keystroke_timing(struct ssh *ssh, struct timespec *timeout,
577 int channel_did_enqueue)
580 static struct timespec next_interval, chaff_until;
581 struct timespec now, tmp;
582 int just_started = 0, had_keystroke = 0;
583 static unsigned long long nchaff;
584 char *stop_reason = NULL;
589 if (options.obscure_keystroke_timing_interval <= 0)
590 return 1; /* disabled in config */
592 if (!channel_still_open(ssh) || quit_pending) {
593 /* Stop if no channels left of we're waiting for one to close */
594 stop_reason = "no active channels";
595 } else if (ssh_packet_is_rekeying(ssh)) {
596 /* Stop if we're rekeying */
597 stop_reason = "rekeying started";
598 } else if (!ssh_packet_interactive_data_to_write(ssh) &&
599 ssh_packet_have_data_to_write(ssh)) {
600 /* Stop if the output buffer has more than a few keystrokes */
601 stop_reason = "output buffer filling";
602 } else if (active && channel_did_enqueue &&
603 ssh_packet_have_data_to_write(ssh)) {
604 /* Still in active mode and have a keystroke queued. */
607 if (timespeccmp(&now, &chaff_until, >=)) {
608 /* Stop if there have been no keystrokes for a while */
609 stop_reason = "chaff time expired";
610 } else if (timespeccmp(&now, &next_interval, >=)) {
611 /* Otherwise if we were due to send, then send chaff */
617 if (stop_reason != NULL) {
619 debug3_f("stopping: %s (%llu chaff packets sent)",
620 stop_reason, nchaff);
627 * If we're in interactive mode, and only have a small amount
628 * of outbound data, then we assume that the user is typing
629 * interactively. In this case, start quantising outbound packets to
630 * fixed time intervals to hide inter-keystroke timing.
632 if (!active && ssh_packet_interactive_data_to_write(ssh) &&
633 channel_did_enqueue && ssh_packet_have_data_to_write(ssh)) {
634 debug3_f("starting: interval ~%dms",
635 options.obscure_keystroke_timing_interval);
636 just_started = had_keystroke = active = 1;
638 set_next_interval(&now, &next_interval,
639 options.obscure_keystroke_timing_interval, 1);
642 /* Don't hold off if obfuscation inactive */
648 * Arrange to send chaff packets for a random interval after
649 * the last keystroke was sent.
651 ms_to_timespec(&tmp, SSH_KEYSTROKE_CHAFF_MIN_MS +
652 arc4random_uniform(SSH_KEYSTROKE_CHAFF_RNG_MS));
653 timespecadd(&now, &tmp, &chaff_until);
656 ptimeout_deadline_monotime_tsp(timeout, &next_interval);
661 /* Don't arm output fd for poll until the timing interval has elapsed */
662 if (timespeccmp(&now, &next_interval, <))
665 /* Calculate number of intervals missed since the last check */
666 n = (now.tv_sec - next_interval.tv_sec) * 1000LL * 1000 * 1000;
667 n += now.tv_nsec - next_interval.tv_nsec;
668 n /= options.obscure_keystroke_timing_interval * 1000LL * 1000;
669 n = (n < 0) ? 1 : n + 1;
671 /* Advance to the next interval */
672 set_next_interval(&now, &next_interval,
673 options.obscure_keystroke_timing_interval * n, 0);
678 * Waits until the client can do something (some data becomes available on
679 * one of the file descriptors).
682 client_wait_until_can_do_something(struct ssh *ssh, struct pollfd **pfdp,
683 u_int *npfd_allocp, u_int *npfd_activep, int channel_did_enqueue,
684 int *conn_in_readyp, int *conn_out_readyp)
686 struct timespec timeout;
690 *conn_in_readyp = *conn_out_readyp = 0;
692 /* Prepare channel poll. First two pollfd entries are reserved */
693 ptimeout_init(&timeout);
694 channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, 2, &timeout);
695 if (*npfd_activep < 2)
696 fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */
698 /* channel_prepare_poll could have closed the last channel */
699 if (session_closed && !channel_still_open(ssh) &&
700 !ssh_packet_have_data_to_write(ssh)) {
701 /* clear events since we did not call poll() */
702 for (p = 0; p < *npfd_activep; p++)
703 (*pfdp)[p].revents = 0;
707 oready = obfuscate_keystroke_timing(ssh, &timeout, channel_did_enqueue);
709 /* Monitor server connection on reserved pollfd entries */
710 (*pfdp)[0].fd = connection_in;
711 (*pfdp)[0].events = POLLIN;
712 (*pfdp)[1].fd = connection_out;
713 (*pfdp)[1].events = (oready && ssh_packet_have_data_to_write(ssh)) ?
717 * Wait for something to happen. This will suspend the process until
718 * some polled descriptor can be read, written, or has some other
719 * event pending, or a timeout expires.
721 set_control_persist_exit_time(ssh);
722 if (control_persist_exit_time > 0)
723 ptimeout_deadline_monotime(&timeout, control_persist_exit_time);
724 if (options.server_alive_interval > 0)
725 ptimeout_deadline_monotime(&timeout, server_alive_time);
726 if (options.rekey_interval > 0 && !ssh_packet_is_rekeying(ssh)) {
727 ptimeout_deadline_sec(&timeout,
728 ssh_packet_get_rekey_timeout(ssh));
731 ret = ppoll(*pfdp, *npfd_activep, ptimeout_get_tsp(&timeout), NULL);
735 * We have to clear the events because we return.
736 * We have to return, because the mainloop checks for the flags
737 * set by the signal handlers.
739 for (p = 0; p < *npfd_activep; p++)
740 (*pfdp)[p].revents = 0;
743 /* Note: we might still have data in the buffers. */
744 quit_message("poll: %s", strerror(errno));
748 *conn_in_readyp = (*pfdp)[0].revents != 0;
749 *conn_out_readyp = (*pfdp)[1].revents != 0;
751 if (options.server_alive_interval > 0 && !*conn_in_readyp &&
752 monotime() >= server_alive_time) {
754 * ServerAlive check is needed. We can't rely on the poll
755 * timing out since traffic on the client side such as port
756 * forwards can keep waking it up.
758 server_alive_check(ssh);
763 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr)
765 /* Flush stdout and stderr buffers. */
766 if (sshbuf_len(bout) > 0)
767 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout),
769 if (sshbuf_len(berr) > 0)
770 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr),
773 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
779 /* Send the suspend signal to the program itself. */
780 kill(getpid(), SIGTSTP);
782 /* Reset window sizes in case they have changed */
783 received_window_change_signal = 1;
785 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
789 client_process_net_input(struct ssh *ssh)
794 * Read input from the server, and add any such data to the buffer of
795 * the packet subsystem.
797 schedule_server_alive_check();
798 if ((r = ssh_packet_process_read(ssh, connection_in)) == 0)
799 return; /* success */
800 if (r == SSH_ERR_SYSTEM_ERROR) {
801 if (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)
803 if (errno == EPIPE) {
804 quit_message("Connection to %s closed by remote host.",
809 quit_message("Read from remote host %s: %s", host, ssh_err(r));
813 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx)
815 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx;
820 * If a TTY was explicitly requested, then a failure to allocate
823 if (cr->action == CONFIRM_TTY &&
824 (options.request_tty == REQUEST_TTY_FORCE ||
825 options.request_tty == REQUEST_TTY_YES))
826 cr->action = CONFIRM_CLOSE;
828 /* XXX suppress on mux _client_ quietmode */
829 tochan = options.log_level >= SYSLOG_LEVEL_ERROR &&
830 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;
832 if (type == SSH2_MSG_CHANNEL_SUCCESS) {
833 debug2("%s request accepted on channel %d",
834 cr->request_type, c->self);
835 } else if (type == SSH2_MSG_CHANNEL_FAILURE) {
837 snprintf(errmsg, sizeof(errmsg),
838 "%s request failed\r\n", cr->request_type);
840 snprintf(errmsg, sizeof(errmsg),
841 "%s request failed on channel %d",
842 cr->request_type, c->self);
844 /* If error occurred on primary session channel, then exit */
845 if (cr->action == CONFIRM_CLOSE && c->self == session_ident)
848 * If error occurred on mux client, append to
852 debug3_f("channel %d: mux request: %s", c->self,
854 if ((r = sshbuf_put(c->extended, errmsg,
855 strlen(errmsg))) != 0)
856 fatal_fr(r, "sshbuf_put");
859 if (cr->action == CONFIRM_TTY) {
861 * If a TTY allocation error occurred, then arrange
862 * for the correct TTY to leave raw mode.
864 if (c->self == session_ident)
867 mux_tty_alloc_failed(ssh, c);
868 } else if (cr->action == CONFIRM_CLOSE) {
869 chan_read_failed(ssh, c);
870 chan_write_failed(ssh, c);
877 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx)
883 client_expect_confirm(struct ssh *ssh, int id, const char *request,
884 enum confirm_action action)
886 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr));
888 cr->request_type = request;
891 channel_register_status_confirm(ssh, id, client_status_confirm,
892 client_abandon_status_confirm, cr);
896 client_register_global_confirm(global_confirm_cb *cb, void *ctx)
898 struct global_confirm *gc, *last_gc;
900 /* Coalesce identical callbacks */
901 last_gc = TAILQ_LAST(&global_confirms, global_confirms);
902 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) {
903 if (++last_gc->ref_count >= INT_MAX)
904 fatal_f("last_gc->ref_count = %d",
909 gc = xcalloc(1, sizeof(*gc));
913 TAILQ_INSERT_TAIL(&global_confirms, gc, entry);
917 * Returns non-zero if the client is able to handle a hostkeys-00@openssh.com
918 * hostkey update request.
921 can_update_hostkeys(void)
923 if (hostkeys_update_complete)
925 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK &&
927 return 0; /* won't ask in batchmode, so don't even try */
928 if (!options.update_hostkeys || options.num_user_hostfiles <= 0)
934 client_repledge(void)
938 /* Might be able to tighten pledge now that session is established */
939 if (options.control_master || options.control_path != NULL ||
940 options.forward_x11 || options.fork_after_authentication ||
941 can_update_hostkeys() ||
942 (session_ident != -1 && !session_setup_complete)) {
947 * LocalCommand and UpdateHostkeys have finished, so can get rid of
950 * XXX protocol allows a server can to change hostkeys during the
951 * connection at rekey time that could trigger a hostkeys update
952 * but AFAIK no implementations support this. Could improve by
953 * forcing known_hosts to be read-only or via unveil(2).
955 if (options.num_local_forwards != 0 ||
956 options.num_remote_forwards != 0 ||
957 options.num_permitted_remote_opens != 0 ||
958 options.enable_escape_commandline != 0) {
959 /* rfwd needs inet */
960 debug("pledge: network");
961 if (pledge("stdio unix inet dns proc tty", NULL) == -1)
962 fatal_f("pledge(): %s", strerror(errno));
963 } else if (options.forward_agent != 0) {
964 /* agent forwarding needs to open $SSH_AUTH_SOCK at will */
965 debug("pledge: agent");
966 if (pledge("stdio unix proc tty", NULL) == -1)
967 fatal_f("pledge(): %s", strerror(errno));
969 debug("pledge: fork");
970 if (pledge("stdio proc tty", NULL) == -1)
971 fatal_f("pledge(): %s", strerror(errno));
973 /* XXX further things to do:
975 * - might be able to get rid of proc if we kill ~^Z
976 * - ssh -N (no session)
978 * - sessions without tty
983 process_cmdline(struct ssh *ssh)
985 void (*handler)(int);
987 int ok, delete = 0, local = 0, remote = 0, dynamic = 0;
990 memset(&fwd, 0, sizeof(fwd));
992 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
993 handler = ssh_signal(SIGINT, SIG_IGN);
994 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
997 while (isspace((u_char)*s))
1000 s++; /* Skip cmdline '-', if any */
1004 if (*s == 'h' || *s == 'H' || *s == '?') {
1006 logit(" -L[bind_address:]port:host:hostport "
1007 "Request local forward");
1008 logit(" -R[bind_address:]port:host:hostport "
1009 "Request remote forward");
1010 logit(" -D[bind_address:]port "
1011 "Request dynamic forward");
1012 logit(" -KL[bind_address:]port "
1013 "Cancel local forward");
1014 logit(" -KR[bind_address:]port "
1015 "Cancel remote forward");
1016 logit(" -KD[bind_address:]port "
1017 "Cancel dynamic forward");
1018 if (!options.permit_local_command)
1021 "Execute local command");
1025 if (*s == '!' && options.permit_local_command) {
1042 logit("Invalid command.");
1046 while (isspace((u_char)*++s))
1049 /* XXX update list of forwards in options */
1051 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */
1052 if (!parse_forward(&fwd, s, 1, 0)) {
1053 logit("Bad forwarding close specification.");
1057 ok = channel_request_rforward_cancel(ssh, &fwd) == 0;
1059 ok = channel_cancel_lport_listener(ssh, &fwd,
1060 0, &options.fwd_opts) > 0;
1062 ok = channel_cancel_lport_listener(ssh, &fwd,
1063 CHANNEL_CANCEL_PORT_STATIC,
1064 &options.fwd_opts) > 0;
1066 logit("Unknown port forwarding.");
1069 logit("Canceled forwarding.");
1071 /* -R specs can be both dynamic or not, so check both. */
1073 if (!parse_forward(&fwd, s, 0, remote) &&
1074 !parse_forward(&fwd, s, 1, remote)) {
1075 logit("Bad remote forwarding specification.");
1078 } else if (!parse_forward(&fwd, s, dynamic, remote)) {
1079 logit("Bad local forwarding specification.");
1082 if (local || dynamic) {
1083 if (!channel_setup_local_fwd_listener(ssh, &fwd,
1084 &options.fwd_opts)) {
1085 logit("Port forwarding failed.");
1089 if (channel_request_remote_forwarding(ssh, &fwd) < 0) {
1090 logit("Port forwarding failed.");
1094 logit("Forwarding port.");
1098 ssh_signal(SIGINT, handler);
1099 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1101 free(fwd.listen_host);
1102 free(fwd.listen_path);
1103 free(fwd.connect_host);
1104 free(fwd.connect_path);
1107 /* reasons to suppress output of an escape command in help output */
1108 #define SUPPRESS_NEVER 0 /* never suppress, always show */
1109 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */
1110 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */
1111 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */
1112 #define SUPPRESS_NOCMDLINE 8 /* don't show when cmdline disabled*/
1113 struct escape_help_text {
1118 static struct escape_help_text esc_txt[] = {
1119 {".", "terminate session", SUPPRESS_MUXMASTER},
1120 {".", "terminate connection (and any multiplexed sessions)",
1121 SUPPRESS_MUXCLIENT},
1122 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER},
1123 {"C", "open a command line", SUPPRESS_MUXCLIENT|SUPPRESS_NOCMDLINE},
1124 {"R", "request rekey", SUPPRESS_NEVER},
1125 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT},
1126 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT},
1127 {"#", "list forwarded connections", SUPPRESS_NEVER},
1128 {"&", "background ssh (when waiting for connections to terminate)",
1129 SUPPRESS_MUXCLIENT},
1130 {"?", "this message", SUPPRESS_NEVER},
1134 print_escape_help(struct sshbuf *b, int escape_char, int mux_client,
1137 unsigned int i, suppress_flags;
1140 if ((r = sshbuf_putf(b,
1141 "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0)
1142 fatal_fr(r, "sshbuf_putf");
1145 (mux_client ? SUPPRESS_MUXCLIENT : 0) |
1146 (mux_client ? 0 : SUPPRESS_MUXMASTER) |
1147 (using_stderr ? 0 : SUPPRESS_SYSLOG) |
1148 (options.enable_escape_commandline == 0 ? SUPPRESS_NOCMDLINE : 0);
1150 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) {
1151 if (esc_txt[i].flags & suppress_flags)
1153 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n",
1154 escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0)
1155 fatal_fr(r, "sshbuf_putf");
1158 if ((r = sshbuf_putf(b,
1159 " %c%c - send the escape character by typing it twice\r\n"
1160 "(Note that escapes are only recognized immediately after "
1161 "newline.)\r\n", escape_char, escape_char)) != 0)
1162 fatal_fr(r, "sshbuf_putf");
1166 * Process the characters one by one.
1169 process_escapes(struct ssh *ssh, Channel *c,
1170 struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr,
1178 struct escape_filter_ctx *efc;
1180 if (c == NULL || c->filter_ctx == NULL || len <= 0)
1183 efc = (struct escape_filter_ctx *)c->filter_ctx;
1185 for (i = 0; i < (u_int)len; i++) {
1186 /* Get one character at a time. */
1189 if (efc->escape_pending) {
1190 /* We have previously seen an escape character. */
1191 /* Clear the flag now. */
1192 efc->escape_pending = 0;
1194 /* Process the escaped character. */
1197 /* Terminate the connection. */
1198 if ((r = sshbuf_putf(berr, "%c.\r\n",
1199 efc->escape_char)) != 0)
1200 fatal_fr(r, "sshbuf_putf");
1201 if (c && c->ctl_chan != -1) {
1202 channel_force_close(ssh, c, 1);
1209 /* XXX support this for mux clients */
1210 if (c && c->ctl_chan != -1) {
1214 snprintf(b, sizeof b, "^Z");
1216 snprintf(b, sizeof b, "%c", ch);
1217 if ((r = sshbuf_putf(berr,
1218 "%c%s escape not available to "
1219 "multiplexed sessions\r\n",
1220 efc->escape_char, b)) != 0)
1221 fatal_fr(r, "sshbuf_putf");
1224 /* Suspend the program. Inform the user */
1225 if ((r = sshbuf_putf(berr,
1226 "%c^Z [suspend ssh]\r\n",
1227 efc->escape_char)) != 0)
1228 fatal_fr(r, "sshbuf_putf");
1230 /* Restore terminal modes and suspend. */
1231 client_suspend_self(bin, bout, berr);
1233 /* We have been continued. */
1237 if ((r = sshbuf_putf(berr,
1238 "%cB\r\n", efc->escape_char)) != 0)
1239 fatal_fr(r, "sshbuf_putf");
1240 channel_request_start(ssh, c->self, "break", 0);
1241 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 ||
1242 (r = sshpkt_send(ssh)) != 0)
1243 fatal_fr(r, "send packet");
1247 if (ssh->compat & SSH_BUG_NOREKEY)
1248 logit("Server does not "
1249 "support re-keying");
1257 if (c && c->ctl_chan != -1)
1259 if (!log_is_on_stderr()) {
1260 if ((r = sshbuf_putf(berr,
1261 "%c%c [Logging to syslog]\r\n",
1262 efc->escape_char, ch)) != 0)
1263 fatal_fr(r, "sshbuf_putf");
1266 if (ch == 'V' && options.log_level >
1268 log_change_level(--options.log_level);
1269 if (ch == 'v' && options.log_level <
1270 SYSLOG_LEVEL_DEBUG3)
1271 log_change_level(++options.log_level);
1272 if ((r = sshbuf_putf(berr,
1273 "%c%c [LogLevel %s]\r\n",
1274 efc->escape_char, ch,
1275 log_level_name(options.log_level))) != 0)
1276 fatal_fr(r, "sshbuf_putf");
1280 if (c->ctl_chan != -1)
1283 * Detach the program (continue to serve
1284 * connections, but put in background and no
1285 * more new connections).
1287 /* Restore tty modes. */
1289 options.request_tty == REQUEST_TTY_FORCE);
1291 /* Stop listening for new connections. */
1292 channel_stop_listening(ssh);
1294 if ((r = sshbuf_putf(berr, "%c& "
1295 "[backgrounded]\n", efc->escape_char)) != 0)
1296 fatal_fr(r, "sshbuf_putf");
1298 /* Fork into background. */
1301 error("fork: %.100s", strerror(errno));
1304 if (pid != 0) { /* This is the parent. */
1305 /* The parent just exits. */
1308 /* The child continues serving connections. */
1309 /* fake EOF on stdin */
1310 if ((r = sshbuf_put_u8(bin, 4)) != 0)
1311 fatal_fr(r, "sshbuf_put_u8");
1314 print_escape_help(berr, efc->escape_char,
1315 (c && c->ctl_chan != -1),
1316 log_is_on_stderr());
1320 if ((r = sshbuf_putf(berr, "%c#\r\n",
1321 efc->escape_char)) != 0)
1322 fatal_fr(r, "sshbuf_putf");
1323 s = channel_open_message(ssh);
1324 if ((r = sshbuf_put(berr, s, strlen(s))) != 0)
1325 fatal_fr(r, "sshbuf_put");
1330 if (c && c->ctl_chan != -1)
1332 if (options.enable_escape_commandline == 0) {
1333 if ((r = sshbuf_putf(berr,
1334 "commandline disabled\r\n")) != 0)
1335 fatal_fr(r, "sshbuf_putf");
1338 process_cmdline(ssh);
1342 if (ch != efc->escape_char) {
1343 if ((r = sshbuf_put_u8(bin,
1344 efc->escape_char)) != 0)
1345 fatal_fr(r, "sshbuf_put_u8");
1348 /* Escaped characters fall through here */
1353 * The previous character was not an escape char.
1354 * Check if this is an escape.
1356 if (last_was_cr && ch == efc->escape_char) {
1358 * It is. Set the flag and continue to
1361 efc->escape_pending = 1;
1367 * Normal character. Record whether it was a newline,
1368 * and append it to the buffer.
1370 last_was_cr = (ch == '\r' || ch == '\n');
1371 if ((r = sshbuf_put_u8(bin, ch)) != 0)
1372 fatal_fr(r, "sshbuf_put_u8");
1379 * Get packets from the connection input buffer, and process them as long as
1380 * there are packets available.
1382 * Any unknown packets received during the actual
1383 * session cause the session to terminate. This is
1384 * intended to make debugging easier since no
1385 * confirmations are sent. Any compatible protocol
1386 * extensions must be negotiated during the
1387 * preparatory phase.
1391 client_process_buffered_input_packets(struct ssh *ssh)
1393 ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, &quit_pending);
1396 /* scan buf[] for '~' before sending data to the peer */
1398 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */
1400 client_new_escape_filter_ctx(int escape_char)
1402 struct escape_filter_ctx *ret;
1404 ret = xcalloc(1, sizeof(*ret));
1405 ret->escape_pending = 0;
1406 ret->escape_char = escape_char;
1410 /* Free the escape filter context on channel free */
1412 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx)
1418 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len)
1420 if (c->extended_usage != CHAN_EXTENDED_WRITE)
1423 return process_escapes(ssh, c, c->input, c->output, c->extended,
1428 client_channel_closed(struct ssh *ssh, int id, int force, void *arg)
1430 channel_cancel_cleanup(ssh, id);
1432 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1436 * Implements the interactive session with the server. This is called after
1437 * the user has been authenticated, and a command has been started on the
1438 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1439 * used as an escape character for terminating or suspending the session.
1442 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg,
1445 struct pollfd *pfd = NULL;
1446 u_int npfd_alloc = 0, npfd_active = 0;
1447 double start_time, total_time;
1448 int channel_did_enqueue = 0, r, len;
1449 u_int64_t ibytes, obytes;
1450 int conn_in_ready, conn_out_ready;
1452 debug("Entering interactive session.");
1453 session_ident = ssh2_chan_id;
1455 if (options.control_master &&
1456 !option_clear_or_none(options.control_path)) {
1457 debug("pledge: id");
1458 if (pledge("stdio rpath wpath cpath unix inet dns recvfd sendfd proc exec id tty",
1460 fatal_f("pledge(): %s", strerror(errno));
1462 } else if (options.forward_x11 || options.permit_local_command) {
1463 debug("pledge: exec");
1464 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty",
1466 fatal_f("pledge(): %s", strerror(errno));
1468 } else if (options.update_hostkeys) {
1469 debug("pledge: filesystem");
1470 if (pledge("stdio rpath wpath cpath unix inet dns proc tty",
1472 fatal_f("pledge(): %s", strerror(errno));
1474 } else if (!option_clear_or_none(options.proxy_command) ||
1475 options.fork_after_authentication) {
1476 debug("pledge: proc");
1477 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1)
1478 fatal_f("pledge(): %s", strerror(errno));
1481 debug("pledge: network");
1482 if (pledge("stdio unix inet dns proc tty", NULL) == -1)
1483 fatal_f("pledge(): %s", strerror(errno));
1486 /* might be able to tighten now */
1489 start_time = monotime_double();
1491 /* Initialize variables. */
1494 connection_in = ssh_packet_get_connection_in(ssh);
1495 connection_out = ssh_packet_get_connection_out(ssh);
1499 /* Initialize buffer. */
1500 if ((stderr_buffer = sshbuf_new()) == NULL)
1501 fatal_f("sshbuf_new failed");
1503 client_init_dispatch(ssh);
1506 * Set signal handlers, (e.g. to restore non-blocking mode)
1507 * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1509 if (ssh_signal(SIGHUP, SIG_IGN) != SIG_IGN)
1510 ssh_signal(SIGHUP, signal_handler);
1511 if (ssh_signal(SIGINT, SIG_IGN) != SIG_IGN)
1512 ssh_signal(SIGINT, signal_handler);
1513 if (ssh_signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1514 ssh_signal(SIGQUIT, signal_handler);
1515 if (ssh_signal(SIGTERM, SIG_IGN) != SIG_IGN)
1516 ssh_signal(SIGTERM, signal_handler);
1517 ssh_signal(SIGWINCH, window_change_handler);
1520 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1522 if (session_ident != -1) {
1523 if (escape_char_arg != SSH_ESCAPECHAR_NONE) {
1524 channel_register_filter(ssh, session_ident,
1525 client_simple_escape_filter, NULL,
1526 client_filter_cleanup,
1527 client_new_escape_filter_ctx(
1530 channel_register_cleanup(ssh, session_ident,
1531 client_channel_closed, 0);
1534 schedule_server_alive_check();
1536 /* Main loop of the client for the interactive session mode. */
1537 while (!quit_pending) {
1538 channel_did_enqueue = 0;
1540 /* Process buffered packets sent by the server. */
1541 client_process_buffered_input_packets(ssh);
1543 if (session_closed && !channel_still_open(ssh))
1546 if (ssh_packet_is_rekeying(ssh)) {
1547 debug("rekeying in progress");
1548 } else if (need_rekeying) {
1549 /* manual rekey request */
1550 debug("need rekeying");
1551 if ((r = kex_start_rekex(ssh)) != 0)
1552 fatal_fr(r, "kex_start_rekex");
1556 * Make packets from buffered channel data, and
1557 * enqueue them for sending to the server.
1559 if (ssh_packet_not_very_much_data_to_write(ssh))
1560 channel_did_enqueue = channel_output_poll(ssh);
1563 * Check if the window size has changed, and buffer a
1564 * message about it to the server if so.
1566 client_check_window_change(ssh);
1572 * Wait until we have something to do (something becomes
1573 * available on one of the descriptors).
1575 client_wait_until_can_do_something(ssh, &pfd, &npfd_alloc,
1576 &npfd_active, channel_did_enqueue,
1577 &conn_in_ready, &conn_out_ready);
1582 /* Do channel operations. */
1583 channel_after_poll(ssh, pfd, npfd_active);
1585 /* Buffer input from the connection. */
1587 client_process_net_input(ssh);
1592 /* A timeout may have triggered rekeying */
1593 if ((r = ssh_packet_check_rekey(ssh)) != 0)
1594 fatal_fr(r, "cannot start rekeying");
1597 * Send as much buffered packet data as possible to the
1600 if (conn_out_ready) {
1601 if ((r = ssh_packet_write_poll(ssh)) != 0) {
1602 sshpkt_fatal(ssh, r,
1603 "%s: ssh_packet_write_poll", __func__);
1608 * If we are a backgrounded control master, and the
1609 * timeout has expired without any active client
1610 * connections, then quit.
1612 if (control_persist_exit_time > 0) {
1613 if (monotime() >= control_persist_exit_time) {
1614 debug("ControlPersist timeout expired");
1621 /* Terminate the session. */
1623 /* Stop watching for window change. */
1624 ssh_signal(SIGWINCH, SIG_DFL);
1626 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
1627 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_BY_APPLICATION)) != 0 ||
1628 (r = sshpkt_put_cstring(ssh, "disconnected by user")) != 0 ||
1629 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* language tag */
1630 (r = sshpkt_send(ssh)) != 0 ||
1631 (r = ssh_packet_write_wait(ssh)) != 0)
1632 fatal_fr(r, "send disconnect");
1634 channel_free_all(ssh);
1637 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1640 * If there was no shell or command requested, there will be no remote
1641 * exit status to be returned. In that case, clear error code if the
1642 * connection was deliberately terminated at this end.
1644 if (options.session_type == SESSION_TYPE_NONE &&
1645 received_signal == SIGTERM) {
1646 received_signal = 0;
1650 if (received_signal) {
1651 verbose("Killed by signal %d.", (int) received_signal);
1656 * In interactive mode (with pseudo tty) display a message indicating
1657 * that the connection has been closed.
1659 if (have_pty && options.log_level >= SYSLOG_LEVEL_INFO)
1660 quit_message("Connection to %s closed.", host);
1662 /* Output any buffered data for stderr. */
1663 if (sshbuf_len(stderr_buffer) > 0) {
1664 len = atomicio(vwrite, fileno(stderr),
1665 (u_char *)sshbuf_ptr(stderr_buffer),
1666 sshbuf_len(stderr_buffer));
1667 if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer))
1668 error("Write failed flushing stderr buffer.");
1669 else if ((r = sshbuf_consume(stderr_buffer, len)) != 0)
1670 fatal_fr(r, "sshbuf_consume");
1673 /* Clear and free any buffers. */
1674 sshbuf_free(stderr_buffer);
1676 /* Report bytes transferred, and transfer rates. */
1677 total_time = monotime_double() - start_time;
1678 ssh_packet_get_bytes(ssh, &ibytes, &obytes);
1679 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds",
1680 (unsigned long long)obytes, (unsigned long long)ibytes, total_time);
1682 verbose("Bytes per second: sent %.1f, received %.1f",
1683 obytes / total_time, ibytes / total_time);
1684 /* Return the exit status of the program. */
1685 debug("Exit status %d", exit_status);
1692 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type,
1693 int rchan, u_int rwindow, u_int rmaxpack)
1696 struct sshbuf *b = NULL;
1697 char *listen_address, *originator_address;
1698 u_int listen_port, originator_port;
1701 /* Get rest of the packet */
1702 if ((r = sshpkt_get_cstring(ssh, &listen_address, NULL)) != 0 ||
1703 (r = sshpkt_get_u32(ssh, &listen_port)) != 0 ||
1704 (r = sshpkt_get_cstring(ssh, &originator_address, NULL)) != 0 ||
1705 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 ||
1706 (r = sshpkt_get_end(ssh)) != 0)
1707 fatal_fr(r, "parse packet");
1709 debug_f("listen %s port %d, originator %s port %d",
1710 listen_address, listen_port, originator_address, originator_port);
1712 if (listen_port > 0xffff)
1713 error_f("invalid listen port");
1714 else if (originator_port > 0xffff)
1715 error_f("invalid originator port");
1717 c = channel_connect_by_listen_address(ssh,
1718 listen_address, listen_port, "forwarded-tcpip",
1719 originator_address);
1722 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
1723 if ((b = sshbuf_new()) == NULL) {
1724 error_f("alloc reply");
1727 /* reconstruct and send to muxclient */
1728 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */
1729 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
1730 (r = sshbuf_put_cstring(b, request_type)) != 0 ||
1731 (r = sshbuf_put_u32(b, rchan)) != 0 ||
1732 (r = sshbuf_put_u32(b, rwindow)) != 0 ||
1733 (r = sshbuf_put_u32(b, rmaxpack)) != 0 ||
1734 (r = sshbuf_put_cstring(b, listen_address)) != 0 ||
1735 (r = sshbuf_put_u32(b, listen_port)) != 0 ||
1736 (r = sshbuf_put_cstring(b, originator_address)) != 0 ||
1737 (r = sshbuf_put_u32(b, originator_port)) != 0 ||
1738 (r = sshbuf_put_stringb(c->output, b)) != 0) {
1739 error_fr(r, "compose for muxclient");
1746 free(originator_address);
1747 free(listen_address);
1752 client_request_forwarded_streamlocal(struct ssh *ssh,
1753 const char *request_type, int rchan)
1759 /* Get the remote path. */
1760 if ((r = sshpkt_get_cstring(ssh, &listen_path, NULL)) != 0 ||
1761 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* reserved */
1762 (r = sshpkt_get_end(ssh)) != 0)
1763 fatal_fr(r, "parse packet");
1765 debug_f("request: %s", listen_path);
1767 c = channel_connect_by_listen_path(ssh, listen_path,
1768 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal");
1774 client_request_x11(struct ssh *ssh, const char *request_type, int rchan)
1778 u_int originator_port;
1781 if (!options.forward_x11) {
1782 error("Warning: ssh server tried X11 forwarding.");
1783 error("Warning: this is probably a break-in attempt by a "
1784 "malicious server.");
1787 if (x11_refuse_time != 0 && monotime() >= x11_refuse_time) {
1788 verbose("Rejected X11 connection after ForwardX11Timeout "
1792 if ((r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 ||
1793 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 ||
1794 (r = sshpkt_get_end(ssh)) != 0)
1795 fatal_fr(r, "parse packet");
1796 /* XXX check permission */
1797 /* XXX range check originator port? */
1798 debug("client_request_x11: request from %s %u", originator,
1801 sock = x11_connect_display(ssh);
1804 c = channel_new(ssh, "x11",
1805 SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1806 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1812 client_request_agent(struct ssh *ssh, const char *request_type, int rchan)
1817 if (!options.forward_agent) {
1818 error("Warning: ssh server tried agent forwarding.");
1819 error("Warning: this is probably a break-in attempt by a "
1820 "malicious server.");
1823 if (forward_agent_sock_path == NULL) {
1824 r = ssh_get_authentication_socket(&sock);
1826 r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock);
1829 if (r != SSH_ERR_AGENT_NOT_PRESENT)
1830 debug_fr(r, "ssh_get_authentication_socket");
1833 if ((r = ssh_agent_bind_hostkey(sock, ssh->kex->initial_hostkey,
1834 ssh->kex->session_id, ssh->kex->initial_sig, 1)) == 0)
1835 debug_f("bound agent to hostkey");
1837 debug2_fr(r, "ssh_agent_bind_hostkey");
1839 c = channel_new(ssh, "authentication agent connection",
1840 SSH_CHANNEL_OPEN, sock, sock, -1,
1841 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
1842 "authentication agent connection", 1);
1848 client_request_tun_fwd(struct ssh *ssh, int tun_mode,
1849 int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx)
1853 char *ifname = NULL;
1855 if (tun_mode == SSH_TUNMODE_NO)
1858 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode);
1860 /* Open local tunnel device */
1861 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) {
1862 error("Tunnel device open failed.");
1865 debug("Tunnel forwarding using interface %s", ifname);
1867 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1868 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1871 #if defined(SSH_TUN_FILTER)
1872 if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
1873 channel_register_filter(ssh, c->self, sys_tun_infilter,
1874 sys_tun_outfilter, NULL, NULL);
1878 channel_register_open_confirm(ssh, c->self, cb, cbctx);
1880 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
1881 (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 ||
1882 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
1883 (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 ||
1884 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 ||
1885 (r = sshpkt_put_u32(ssh, tun_mode)) != 0 ||
1886 (r = sshpkt_put_u32(ssh, remote_tun)) != 0 ||
1887 (r = sshpkt_send(ssh)) != 0)
1888 sshpkt_fatal(ssh, r, "%s: send reply", __func__);
1893 /* XXXX move to generic input handler */
1895 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh)
1902 u_int rmaxpack, rwindow;
1904 if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 ||
1905 (r = sshpkt_get_u32(ssh, &rchan)) != 0 ||
1906 (r = sshpkt_get_u32(ssh, &rwindow)) != 0 ||
1907 (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0)
1910 debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1911 ctype, rchan, rwindow, rmaxpack);
1913 if (strcmp(ctype, "forwarded-tcpip") == 0) {
1914 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow,
1916 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) {
1917 c = client_request_forwarded_streamlocal(ssh, ctype, rchan);
1918 } else if (strcmp(ctype, "x11") == 0) {
1919 c = client_request_x11(ssh, ctype, rchan);
1920 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1921 c = client_request_agent(ssh, ctype, rchan);
1923 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
1924 debug3("proxied to downstream: %s", ctype);
1925 } else if (c != NULL) {
1926 debug("confirm %s", ctype);
1927 c->remote_id = rchan;
1928 c->have_remote_id = 1;
1929 c->remote_window = rwindow;
1930 c->remote_maxpacket = rmaxpack;
1931 if (c->type != SSH_CHANNEL_CONNECTING) {
1932 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 ||
1933 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1934 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
1935 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
1936 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 ||
1937 (r = sshpkt_send(ssh)) != 0)
1938 sshpkt_fatal(ssh, r, "%s: send reply", __func__);
1941 debug("failure %s", ctype);
1942 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 ||
1943 (r = sshpkt_put_u32(ssh, rchan)) != 0 ||
1944 (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 ||
1945 (r = sshpkt_put_cstring(ssh, "open failed")) != 0 ||
1946 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1947 (r = sshpkt_send(ssh)) != 0)
1948 sshpkt_fatal(ssh, r, "%s: send failure", __func__);
1957 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh)
1965 if ((r = sshpkt_get_u32(ssh, &id)) != 0)
1968 c = channel_lookup(ssh, id);
1969 if (channel_proxy_upstream(c, type, seq, ssh))
1971 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 ||
1972 (r = sshpkt_get_u8(ssh, &reply)) != 0)
1975 debug("client_input_channel_req: channel %u rtype %s reply %d",
1979 error("client_input_channel_req: channel %d: "
1980 "unknown channel", id);
1981 } else if (strcmp(rtype, "eow@openssh.com") == 0) {
1982 if ((r = sshpkt_get_end(ssh)) != 0)
1984 chan_rcvd_eow(ssh, c);
1985 } else if (strcmp(rtype, "exit-status") == 0) {
1986 if ((r = sshpkt_get_u32(ssh, &exitval)) != 0)
1988 if (c->ctl_chan != -1) {
1989 mux_exit_message(ssh, c, exitval);
1991 } else if ((int)id == session_ident) {
1992 /* Record exit value of local session */
1994 exit_status = exitval;
1996 /* Probably for a mux channel that has already closed */
1997 debug_f("no sink for exit-status on channel %d",
2000 if ((r = sshpkt_get_end(ssh)) != 0)
2003 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) {
2004 if (!c->have_remote_id)
2005 fatal_f("channel %d: no remote_id", c->self);
2006 if ((r = sshpkt_start(ssh, success ?
2007 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 ||
2008 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
2009 (r = sshpkt_send(ssh)) != 0)
2010 sshpkt_fatal(ssh, r, "%s: send failure", __func__);
2018 struct hostkeys_update_ctx {
2019 /* The hostname and (optionally) IP address string for the server */
2020 char *host_str, *ip_str;
2023 * Keys received from the server and a flag for each indicating
2024 * whether they already exist in known_hosts.
2025 * keys_match is filled in by hostkeys_find() and later (for new
2026 * keys) by client_global_hostkeys_prove_confirm().
2028 struct sshkey **keys;
2029 u_int *keys_match; /* mask of HKF_MATCH_* from hostfile.h */
2030 int *keys_verified; /* flag for new keys verified by server */
2031 size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */
2034 * Keys that are in known_hosts, but were not present in the update
2035 * from the server (i.e. scheduled to be deleted).
2036 * Filled in by hostkeys_find().
2038 struct sshkey **old_keys;
2041 /* Various special cases. */
2042 int complex_hostspec; /* wildcard or manual pattern-list host name */
2043 int ca_available; /* saw CA key for this host */
2044 int old_key_seen; /* saw old key with other name/addr */
2045 int other_name_seen; /* saw key with other name/addr */
2049 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx)
2055 for (i = 0; i < ctx->nkeys; i++)
2056 sshkey_free(ctx->keys[i]);
2058 free(ctx->keys_match);
2059 free(ctx->keys_verified);
2060 for (i = 0; i < ctx->nold; i++)
2061 sshkey_free(ctx->old_keys[i]);
2062 free(ctx->old_keys);
2063 free(ctx->host_str);
2069 * Returns non-zero if a known_hosts hostname list is not of a form that
2070 * can be handled by UpdateHostkeys. These include wildcard hostnames and
2071 * hostnames lists that do not follow the form host[,ip].
2074 hostspec_is_complex(const char *hosts)
2079 if (strchr(hosts, '*') != NULL || strchr(hosts, '?') != NULL)
2081 /* single host/ip = ok */
2082 if ((cp = strchr(hosts, ',')) == NULL)
2084 /* more than two entries on the line */
2085 if (strchr(cp + 1, ',') != NULL)
2087 /* XXX maybe parse cp+1 and ensure it is an IP? */
2091 /* callback to search for ctx->keys in known_hosts */
2093 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx)
2095 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
2097 struct sshkey **tmp;
2101 if (l->status != HKF_STATUS_MATCHED) {
2102 /* Record if one of the keys appears on a non-matching line */
2103 for (i = 0; i < ctx->nkeys; i++) {
2104 if (sshkey_equal(l->key, ctx->keys[i])) {
2105 ctx->other_name_seen = 1;
2106 debug3_f("found %s key under different "
2107 "name/addr at %s:%ld",
2108 sshkey_ssh_name(ctx->keys[i]),
2109 l->path, l->linenum);
2115 /* Don't proceed if revocation or CA markers are present */
2116 /* XXX relax this */
2117 if (l->marker != MRK_NONE) {
2118 debug3_f("hostkeys file %s:%ld has CA/revocation marker",
2119 l->path, l->linenum);
2120 ctx->complex_hostspec = 1;
2124 /* If CheckHostIP is enabled, then check for mismatched hostname/addr */
2125 if (ctx->ip_str != NULL && strchr(l->hosts, ',') != NULL) {
2126 if ((l->match & HKF_MATCH_HOST) == 0) {
2127 /* Record if address matched a different hostname. */
2128 ctx->other_name_seen = 1;
2129 debug3_f("found address %s against different hostname "
2130 "at %s:%ld", ctx->ip_str, l->path, l->linenum);
2132 } else if ((l->match & HKF_MATCH_IP) == 0) {
2133 /* Record if hostname matched a different address. */
2134 ctx->other_name_seen = 1;
2135 debug3_f("found hostname %s against different address "
2136 "at %s:%ld", ctx->host_str, l->path, l->linenum);
2141 * UpdateHostkeys is skipped for wildcard host names and hostnames
2142 * that contain more than two entries (ssh never writes these).
2144 if (hostspec_is_complex(l->hosts)) {
2145 debug3_f("hostkeys file %s:%ld complex host specification",
2146 l->path, l->linenum);
2147 ctx->complex_hostspec = 1;
2151 /* Mark off keys we've already seen for this host */
2152 for (i = 0; i < ctx->nkeys; i++) {
2153 if (!sshkey_equal(l->key, ctx->keys[i]))
2155 debug3_f("found %s key at %s:%ld",
2156 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum);
2157 ctx->keys_match[i] |= l->match;
2160 /* This line contained a key that not offered by the server */
2161 debug3_f("deprecated %s key at %s:%ld", sshkey_ssh_name(l->key),
2162 l->path, l->linenum);
2163 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1,
2164 sizeof(*ctx->old_keys))) == NULL)
2165 fatal_f("recallocarray failed nold = %zu", ctx->nold);
2166 ctx->old_keys = tmp;
2167 ctx->old_keys[ctx->nold++] = l->key;
2173 /* callback to search for ctx->old_keys in known_hosts under other names */
2175 hostkeys_check_old(struct hostkey_foreach_line *l, void *_ctx)
2177 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
2181 /* only care about lines that *don't* match the active host spec */
2182 if (l->status == HKF_STATUS_MATCHED || l->key == NULL)
2185 hashed = l->match & (HKF_MATCH_HOST_HASHED|HKF_MATCH_IP_HASHED);
2186 for (i = 0; i < ctx->nold; i++) {
2187 if (!sshkey_equal(l->key, ctx->old_keys[i]))
2189 debug3_f("found deprecated %s key at %s:%ld as %s",
2190 sshkey_ssh_name(ctx->old_keys[i]), l->path, l->linenum,
2191 hashed ? "[HASHED]" : l->hosts);
2192 ctx->old_key_seen = 1;
2199 * Check known_hosts files for deprecated keys under other names. Returns 0
2200 * on success or -1 on failure. Updates ctx->old_key_seen if deprecated keys
2201 * exist under names other than the active hostname/IP.
2204 check_old_keys_othernames(struct hostkeys_update_ctx *ctx)
2209 debug2_f("checking for %zu deprecated keys", ctx->nold);
2210 for (i = 0; i < options.num_user_hostfiles; i++) {
2211 debug3_f("searching %s for %s / %s",
2212 options.user_hostfiles[i], ctx->host_str,
2213 ctx->ip_str ? ctx->ip_str : "(none)");
2214 if ((r = hostkeys_foreach(options.user_hostfiles[i],
2215 hostkeys_check_old, ctx, ctx->host_str, ctx->ip_str,
2216 HKF_WANT_PARSE_KEY, 0)) != 0) {
2217 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
2218 debug_f("hostkeys file %s does not exist",
2219 options.user_hostfiles[i]);
2222 error_fr(r, "hostkeys_foreach failed for %s",
2223 options.user_hostfiles[i]);
2231 hostkey_change_preamble(LogLevel loglevel)
2233 do_log2(loglevel, "The server has updated its host keys.");
2234 do_log2(loglevel, "These changes were verified by the server's "
2235 "existing trusted key.");
2239 update_known_hosts(struct hostkeys_update_ctx *ctx)
2241 int r, was_raw = 0, first = 1;
2242 int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK;
2243 LogLevel loglevel = asking ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE;
2244 char *fp, *response;
2248 for (i = 0; i < ctx->nkeys; i++) {
2249 if (!ctx->keys_verified[i])
2251 if ((fp = sshkey_fingerprint(ctx->keys[i],
2252 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
2253 fatal_f("sshkey_fingerprint failed");
2254 if (first && asking)
2255 hostkey_change_preamble(loglevel);
2256 do_log2(loglevel, "Learned new hostkey: %s %s",
2257 sshkey_type(ctx->keys[i]), fp);
2261 for (i = 0; i < ctx->nold; i++) {
2262 if ((fp = sshkey_fingerprint(ctx->old_keys[i],
2263 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
2264 fatal_f("sshkey_fingerprint failed");
2265 if (first && asking)
2266 hostkey_change_preamble(loglevel);
2267 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s",
2268 sshkey_type(ctx->old_keys[i]), fp);
2272 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
2273 if (get_saved_tio() != NULL) {
2278 for (i = 0; !quit_pending && i < 3; i++) {
2280 response = read_passphrase("Accept updated hostkeys? "
2281 "(yes/no): ", RP_ECHO);
2282 if (response != NULL && strcasecmp(response, "yes") == 0)
2284 else if (quit_pending || response == NULL ||
2285 strcasecmp(response, "no") == 0) {
2286 options.update_hostkeys = 0;
2289 do_log2(loglevel, "Please enter "
2290 "\"yes\" or \"no\"");
2293 if (quit_pending || i >= 3 || response == NULL)
2294 options.update_hostkeys = 0;
2299 if (options.update_hostkeys == 0)
2302 * Now that all the keys are verified, we can go ahead and replace
2303 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't
2304 * cancel the operation).
2306 for (i = 0; i < options.num_user_hostfiles; i++) {
2308 * NB. keys are only added to hostfiles[0], for the rest we
2309 * just delete the hostname entries.
2311 if (stat(options.user_hostfiles[i], &sb) != 0) {
2312 if (errno == ENOENT) {
2313 debug_f("known hosts file %s does not "
2314 "exist", options.user_hostfiles[i]);
2316 error_f("known hosts file %s "
2318 options.user_hostfiles[i], strerror(errno));
2322 if ((r = hostfile_replace_entries(options.user_hostfiles[i],
2323 ctx->host_str, ctx->ip_str,
2324 i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0,
2325 options.hash_known_hosts, 0,
2326 options.fingerprint_hash)) != 0) {
2327 error_fr(r, "hostfile_replace_entries failed for %s",
2328 options.user_hostfiles[i]);
2334 client_global_hostkeys_prove_confirm(struct ssh *ssh, int type,
2335 u_int32_t seq, void *_ctx)
2337 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
2339 struct sshbuf *signdata;
2342 const char *rsa_kexalg = NULL;
2347 fatal_f("ctx->nnew == 0"); /* sanity */
2348 if (type != SSH2_MSG_REQUEST_SUCCESS) {
2349 error("Server failed to confirm ownership of "
2350 "private host keys");
2351 hostkeys_update_ctx_free(ctx);
2354 if (sshkey_type_plain(sshkey_type_from_name(
2355 ssh->kex->hostkey_alg)) == KEY_RSA)
2356 rsa_kexalg = ssh->kex->hostkey_alg;
2357 if ((signdata = sshbuf_new()) == NULL)
2358 fatal_f("sshbuf_new failed");
2360 * Expect a signature for each of the ctx->nnew private keys we
2361 * haven't seen before. They will be in the same order as the
2362 * ctx->keys where the corresponding ctx->keys_match[i] == 0.
2364 for (ndone = i = 0; i < ctx->nkeys; i++) {
2365 if (ctx->keys_match[i])
2367 plaintype = sshkey_type_plain(ctx->keys[i]->type);
2368 /* Prepare data to be signed: session ID, unique string, key */
2369 sshbuf_reset(signdata);
2370 if ( (r = sshbuf_put_cstring(signdata,
2371 "hostkeys-prove-00@openssh.com")) != 0 ||
2372 (r = sshbuf_put_stringb(signdata,
2373 ssh->kex->session_id)) != 0 ||
2374 (r = sshkey_puts(ctx->keys[i], signdata)) != 0)
2375 fatal_fr(r, "compose signdata");
2376 /* Extract and verify signature */
2377 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) {
2378 error_fr(r, "parse sig");
2381 if ((r = sshkey_get_sigtype(sig, siglen, &alg)) != 0) {
2382 error_fr(r, "server gave unintelligible signature "
2383 "for %s key %zu", sshkey_type(ctx->keys[i]), i);
2387 * Special case for RSA keys: if a RSA hostkey was negotiated,
2388 * then use its signature type for verification of RSA hostkey
2389 * proofs. Otherwise, accept only RSA-SHA256/512 signatures.
2391 if (plaintype == KEY_RSA && rsa_kexalg == NULL &&
2392 match_pattern_list(alg, HOSTKEY_PROOF_RSA_ALGS, 0) != 1) {
2393 debug_f("server used untrusted RSA signature algorithm "
2394 "%s for key %zu, disregarding", alg, i);
2396 /* zap the key from the list */
2397 sshkey_free(ctx->keys[i]);
2398 ctx->keys[i] = NULL;
2402 debug3_f("verify %s key %zu using sigalg %s",
2403 sshkey_type(ctx->keys[i]), i, alg);
2405 if ((r = sshkey_verify(ctx->keys[i], sig, siglen,
2406 sshbuf_ptr(signdata), sshbuf_len(signdata),
2407 plaintype == KEY_RSA ? rsa_kexalg : NULL, 0, NULL)) != 0) {
2408 error_fr(r, "server gave bad signature for %s key %zu",
2409 sshkey_type(ctx->keys[i]), i);
2412 /* Key is good. Mark it as 'seen' */
2413 ctx->keys_verified[i] = 1;
2416 /* Shouldn't happen */
2417 if (ndone != ctx->nnew)
2418 fatal_f("ndone != ctx->nnew (%zu / %zu)", ndone, ctx->nnew);
2419 if ((r = sshpkt_get_end(ssh)) != 0) {
2420 error_f("protocol error");
2424 /* Make the edits to known_hosts */
2425 update_known_hosts(ctx);
2427 hostkeys_update_ctx_free(ctx);
2428 hostkeys_update_complete = 1;
2433 * Returns non-zero if the key is accepted by HostkeyAlgorithms.
2434 * Made slightly less trivial by the multiple RSA signature algorithm names.
2437 key_accepted_by_hostkeyalgs(const struct sshkey *key)
2439 const char *ktype = sshkey_ssh_name(key);
2440 const char *hostkeyalgs = options.hostkeyalgorithms;
2442 if (key->type == KEY_UNSPEC)
2444 if (key->type == KEY_RSA &&
2445 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 ||
2446 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1))
2448 return match_pattern_list(ktype, hostkeyalgs, 0) == 1;
2452 * Handle hostkeys-00@openssh.com global request to inform the client of all
2453 * the server's hostkeys. The keys are checked against the user's
2454 * HostkeyAlgorithms preference before they are accepted.
2457 client_input_hostkeys(struct ssh *ssh)
2459 const u_char *blob = NULL;
2461 struct sshbuf *buf = NULL;
2462 struct sshkey *key = NULL, **tmp;
2463 int r, prove_sent = 0;
2465 static int hostkeys_seen = 0; /* XXX use struct ssh */
2466 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */
2467 struct hostkeys_update_ctx *ctx = NULL;
2471 fatal_f("server already sent hostkeys");
2472 if (!can_update_hostkeys())
2476 ctx = xcalloc(1, sizeof(*ctx));
2477 while (ssh_packet_remaining(ssh) > 0) {
2480 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) {
2481 error_fr(r, "parse key");
2484 if ((r = sshkey_from_blob(blob, len, &key)) != 0) {
2485 do_log2_fr(r, r == SSH_ERR_KEY_TYPE_UNKNOWN ?
2486 SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR,
2490 fp = sshkey_fingerprint(key, options.fingerprint_hash,
2492 debug3_f("received %s key %s", sshkey_type(key), fp);
2495 if (!key_accepted_by_hostkeyalgs(key)) {
2496 debug3_f("%s key not permitted by "
2497 "HostkeyAlgorithms", sshkey_ssh_name(key));
2501 if (sshkey_is_cert(key)) {
2502 debug3_f("%s key is a certificate; skipping",
2503 sshkey_ssh_name(key));
2506 /* Ensure keys are unique */
2507 for (i = 0; i < ctx->nkeys; i++) {
2508 if (sshkey_equal(key, ctx->keys[i])) {
2509 error_f("received duplicated %s host key",
2510 sshkey_ssh_name(key));
2514 /* Key is good, record it */
2515 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1,
2516 sizeof(*ctx->keys))) == NULL)
2517 fatal_f("recallocarray failed nkeys = %zu",
2520 ctx->keys[ctx->nkeys++] = key;
2524 if (ctx->nkeys == 0) {
2525 debug_f("server sent no hostkeys");
2529 if ((ctx->keys_match = calloc(ctx->nkeys,
2530 sizeof(*ctx->keys_match))) == NULL ||
2531 (ctx->keys_verified = calloc(ctx->nkeys,
2532 sizeof(*ctx->keys_verified))) == NULL)
2533 fatal_f("calloc failed");
2535 get_hostfile_hostname_ipaddr(host,
2536 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL,
2537 options.port, &ctx->host_str,
2538 options.check_host_ip ? &ctx->ip_str : NULL);
2540 /* Find which keys we already know about. */
2541 for (i = 0; i < options.num_user_hostfiles; i++) {
2542 debug_f("searching %s for %s / %s",
2543 options.user_hostfiles[i], ctx->host_str,
2544 ctx->ip_str ? ctx->ip_str : "(none)");
2545 if ((r = hostkeys_foreach(options.user_hostfiles[i],
2546 hostkeys_find, ctx, ctx->host_str, ctx->ip_str,
2547 HKF_WANT_PARSE_KEY, 0)) != 0) {
2548 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
2549 debug_f("hostkeys file %s does not exist",
2550 options.user_hostfiles[i]);
2553 error_fr(r, "hostkeys_foreach failed for %s",
2554 options.user_hostfiles[i]);
2559 /* Figure out if we have any new keys to add */
2560 ctx->nnew = ctx->nincomplete = 0;
2561 want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0);
2562 for (i = 0; i < ctx->nkeys; i++) {
2563 if (ctx->keys_match[i] == 0)
2565 if ((ctx->keys_match[i] & want) != want)
2569 debug3_f("%zu server keys: %zu new, %zu retained, "
2570 "%zu incomplete match. %zu to remove", ctx->nkeys, ctx->nnew,
2571 ctx->nkeys - ctx->nnew - ctx->nincomplete,
2572 ctx->nincomplete, ctx->nold);
2574 if (ctx->nnew == 0 && ctx->nold == 0) {
2575 debug_f("no new or deprecated keys from server");
2579 /* Various reasons why we cannot proceed with the update */
2580 if (ctx->complex_hostspec) {
2581 debug_f("CA/revocation marker, manual host list or wildcard "
2582 "host pattern found, skipping UserKnownHostsFile update");
2585 if (ctx->other_name_seen) {
2586 debug_f("host key found matching a different name/address, "
2587 "skipping UserKnownHostsFile update");
2591 * If removing keys, check whether they appear under different
2592 * names/addresses and refuse to proceed if they do. This avoids
2593 * cases such as hosts with multiple names becoming inconsistent
2594 * with regards to CheckHostIP entries.
2595 * XXX UpdateHostkeys=force to override this (and other) checks?
2597 if (ctx->nold != 0) {
2598 if (check_old_keys_othernames(ctx) != 0)
2599 goto out; /* error already logged */
2600 if (ctx->old_key_seen) {
2601 debug_f("key(s) for %s%s%s exist under other names; "
2602 "skipping UserKnownHostsFile update",
2603 ctx->host_str, ctx->ip_str == NULL ? "" : ",",
2604 ctx->ip_str == NULL ? "" : ctx->ip_str);
2609 if (ctx->nnew == 0) {
2611 * We have some keys to remove or fix matching for.
2612 * We can proceed to do this without requiring a fresh proof
2615 update_known_hosts(ctx);
2619 * We have received previously-unseen keys from the server.
2620 * Ask the server to confirm ownership of the private halves.
2622 debug3_f("asking server to prove ownership for %zu keys", ctx->nnew);
2623 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2624 (r = sshpkt_put_cstring(ssh,
2625 "hostkeys-prove-00@openssh.com")) != 0 ||
2626 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */
2627 fatal_fr(r, "prepare hostkeys-prove");
2628 if ((buf = sshbuf_new()) == NULL)
2629 fatal_f("sshbuf_new");
2630 for (i = 0; i < ctx->nkeys; i++) {
2631 if (ctx->keys_match[i])
2634 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0 ||
2635 (r = sshpkt_put_stringb(ssh, buf)) != 0)
2636 fatal_fr(r, "assemble hostkeys-prove");
2638 if ((r = sshpkt_send(ssh)) != 0)
2639 fatal_fr(r, "send hostkeys-prove");
2640 client_register_global_confirm(
2641 client_global_hostkeys_prove_confirm, ctx);
2642 ctx = NULL; /* will be freed in callback */
2647 hostkeys_update_ctx_free(ctx);
2651 /* UpdateHostkeys handling completed */
2652 hostkeys_update_complete = 1;
2656 * NB. Return success for all cases. The server doesn't need to know
2657 * what the client does with its hosts file.
2663 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh)
2669 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 ||
2670 (r = sshpkt_get_u8(ssh, &want_reply)) != 0)
2672 debug("client_input_global_request: rtype %s want_reply %d",
2674 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0)
2675 success = client_input_hostkeys(ssh);
2677 if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS :
2678 SSH2_MSG_REQUEST_FAILURE)) != 0 ||
2679 (r = sshpkt_send(ssh)) != 0 ||
2680 (r = ssh_packet_write_wait(ssh)) != 0)
2690 client_send_env(struct ssh *ssh, int id, const char *name, const char *val)
2694 debug("channel %d: setting env %s = \"%s\"", id, name, val);
2695 channel_request_start(ssh, id, "env", 0);
2696 if ((r = sshpkt_put_cstring(ssh, name)) != 0 ||
2697 (r = sshpkt_put_cstring(ssh, val)) != 0 ||
2698 (r = sshpkt_send(ssh)) != 0)
2699 fatal_fr(r, "send setenv");
2703 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem,
2704 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd,
2712 debug2_f("id %d", id);
2714 if ((c = channel_lookup(ssh, id)) == NULL)
2715 fatal_f("channel %d: unknown channel", id);
2717 ssh_packet_set_interactive(ssh, want_tty,
2718 options.ip_qos_interactive, options.ip_qos_bulk);
2723 /* Store window size in the packet. */
2724 if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1)
2725 memset(&ws, 0, sizeof(ws));
2727 channel_request_start(ssh, id, "pty-req", 1);
2728 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY);
2729 if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : ""))
2731 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 ||
2732 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 ||
2733 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 ||
2734 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0)
2735 fatal_fr(r, "build pty-req");
2737 tiop = get_saved_tio();
2738 ssh_tty_make_modes(ssh, -1, tiop);
2739 if ((r = sshpkt_send(ssh)) != 0)
2740 fatal_fr(r, "send pty-req");
2741 /* XXX wait for reply */
2745 /* Transfer any environment variables from client to server */
2746 if (options.num_send_env != 0 && env != NULL) {
2747 debug("Sending environment.");
2748 for (i = 0; env[i] != NULL; i++) {
2750 name = xstrdup(env[i]);
2751 if ((val = strchr(name, '=')) == NULL) {
2758 for (j = 0; j < options.num_send_env; j++) {
2759 if (match_pattern(name, options.send_env[j])) {
2765 debug3("Ignored env %s", name);
2769 client_send_env(ssh, id, name, val);
2773 for (i = 0; i < options.num_setenv; i++) {
2775 name = xstrdup(options.setenv[i]);
2776 if ((val = strchr(name, '=')) == NULL) {
2781 client_send_env(ssh, id, name, val);
2785 len = sshbuf_len(cmd);
2789 if (want_subsystem) {
2790 debug("Sending subsystem: %.*s",
2791 (int)len, (const u_char*)sshbuf_ptr(cmd));
2792 channel_request_start(ssh, id, "subsystem", 1);
2793 client_expect_confirm(ssh, id, "subsystem",
2796 debug("Sending command: %.*s",
2797 (int)len, (const u_char*)sshbuf_ptr(cmd));
2798 channel_request_start(ssh, id, "exec", 1);
2799 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE);
2801 if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 ||
2802 (r = sshpkt_send(ssh)) != 0)
2803 fatal_fr(r, "send command");
2805 channel_request_start(ssh, id, "shell", 1);
2806 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE);
2807 if ((r = sshpkt_send(ssh)) != 0)
2808 fatal_fr(r, "send shell");
2811 session_setup_complete = 1;
2816 client_init_dispatch(struct ssh *ssh)
2818 ssh_dispatch_init(ssh, &dispatch_protocol_error);
2820 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
2821 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data);
2822 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
2823 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
2824 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
2825 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
2826 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
2827 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
2828 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
2829 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
2830 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
2831 ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
2834 ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit);
2836 /* global request reply messages */
2837 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
2838 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
2842 client_stop_mux(void)
2844 if (options.control_path != NULL && muxserver_sock != -1)
2845 unlink(options.control_path);
2847 * If we are in persist mode, or don't have a shell, signal that we
2848 * should close when all active channels are closed.
2850 if (options.control_persist || options.session_type == SESSION_TYPE_NONE) {
2852 setproctitle("[stopped mux]");
2856 /* client specific fatal cleanup */
2860 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
2861 if (options.control_path != NULL && muxserver_sock != -1)
2862 unlink(options.control_path);
2863 ssh_kill_proxy_command();