1 /* $OpenBSD: clientloop.c,v 1.392 2023/04/03 08:10:54 dtucker 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"
122 extern Options options;
125 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */
128 * Name of the host we are connecting to. This is the name given on the
129 * command line, or the Hostname specified for the user-supplied name in a
130 * configuration file.
135 * If this field is not NULL, the ForwardAgent socket is this path and different
136 * instead of SSH_AUTH_SOCK.
138 extern char *forward_agent_sock_path;
141 * Flag to indicate that we have received a window change signal which has
142 * not yet been processed. This will cause a message indicating the new
143 * window size to be sent to the server a little later. This is volatile
144 * because this is updated in a signal handler.
146 static volatile sig_atomic_t received_window_change_signal = 0;
147 static volatile sig_atomic_t received_signal = 0;
149 /* Time when backgrounded control master using ControlPersist should exit */
150 static time_t control_persist_exit_time = 0;
152 /* Common data for the client loop code. */
153 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */
154 static int last_was_cr; /* Last character was a newline. */
155 static int exit_status; /* Used to store the command exit status. */
156 static struct sshbuf *stderr_buffer; /* Used for final exit message. */
157 static int connection_in; /* Connection to server (input). */
158 static int connection_out; /* Connection to server (output). */
159 static int need_rekeying; /* Set to non-zero if rekeying is requested. */
160 static int session_closed; /* In SSH2: login session closed. */
161 static time_t x11_refuse_time; /* If >0, refuse x11 opens after this time. */
162 static time_t server_alive_time; /* Time to do server_alive_check */
163 static int hostkeys_update_complete;
164 static int session_setup_complete;
166 static void client_init_dispatch(struct ssh *ssh);
167 int session_ident = -1;
169 /* Track escape per proto2 channel */
170 struct escape_filter_ctx {
175 /* Context for channel confirmation replies */
176 struct channel_reply_ctx {
177 const char *request_type;
179 enum confirm_action action;
182 /* Global request success/failure callbacks */
183 /* XXX move to struct ssh? */
184 struct global_confirm {
185 TAILQ_ENTRY(global_confirm) entry;
186 global_confirm_cb *cb;
190 TAILQ_HEAD(global_confirms, global_confirm);
191 static struct global_confirms global_confirms =
192 TAILQ_HEAD_INITIALIZER(global_confirms);
194 void ssh_process_session2_setup(int, int, int, struct sshbuf *);
195 static void quit_message(const char *fmt, ...)
196 __attribute__((__format__ (printf, 1, 2)));
199 quit_message(const char *fmt, ...)
206 xvasprintf(&msg, fmt, args);
209 if ((r = sshbuf_putf(stderr_buffer, "%s\r\n", msg)) != 0)
210 fatal_fr(r, "sshbuf_putf");
215 * Signal handler for the window change signal (SIGWINCH). This just sets a
216 * flag indicating that the window has changed.
219 window_change_handler(int sig)
221 received_window_change_signal = 1;
225 * Signal handler for signals that cause the program to terminate. These
226 * signals must be trapped to restore terminal modes.
229 signal_handler(int sig)
231 received_signal = sig;
236 * Sets control_persist_exit_time to the absolute time when the
237 * backgrounded control master should exit due to expiry of the
238 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded
239 * control master process, or if there is no ControlPersist timeout.
242 set_control_persist_exit_time(struct ssh *ssh)
244 if (muxserver_sock == -1 || !options.control_persist
245 || options.control_persist_timeout == 0) {
246 /* not using a ControlPersist timeout */
247 control_persist_exit_time = 0;
248 } else if (channel_still_open(ssh)) {
249 /* some client connections are still open */
250 if (control_persist_exit_time > 0)
251 debug2_f("cancel scheduled exit");
252 control_persist_exit_time = 0;
253 } else if (control_persist_exit_time <= 0) {
254 /* a client connection has recently closed */
255 control_persist_exit_time = monotime() +
256 (time_t)options.control_persist_timeout;
257 debug2_f("schedule exit in %d seconds",
258 options.control_persist_timeout);
260 /* else we are already counting down to the timeout */
263 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_"
265 client_x11_display_valid(const char *display)
272 dlen = strlen(display);
273 for (i = 0; i < dlen; i++) {
274 if (!isalnum((u_char)display[i]) &&
275 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) {
276 debug("Invalid character '%c' in DISPLAY", display[i]);
283 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1"
284 #define X11_TIMEOUT_SLACK 60
286 client_x11_get_proto(struct ssh *ssh, const char *display,
287 const char *xauth_path, u_int trusted, u_int timeout,
288 char **_proto, char **_data)
290 char *cmd, line[512], xdisplay[512];
291 char xauthfile[PATH_MAX], xauthdir[PATH_MAX];
292 static char proto[512], data[512];
294 int got_data = 0, generated = 0, do_unlink = 0, r;
296 u_int now, x11_timeout_real;
300 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0';
302 if (!client_x11_display_valid(display)) {
304 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding",
308 if (xauth_path != NULL && stat(xauth_path, &st) == -1) {
309 debug("No xauth program.");
313 if (xauth_path != NULL) {
315 * Handle FamilyLocal case where $DISPLAY does
316 * not match an authorization entry. For this we
317 * just try "xauth list unix:displaynum.screennum".
318 * XXX: "localhost" match to determine FamilyLocal
321 if (strncmp(display, "localhost:", 10) == 0) {
322 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s",
323 display + 10)) < 0 ||
324 (size_t)r >= sizeof(xdisplay)) {
325 error_f("display name too long");
332 * Generate an untrusted X11 auth cookie.
334 * The authentication cookie should briefly outlive
335 * ssh's willingness to forward X11 connections to
336 * avoid nasty fail-open behaviour in the X server.
338 mktemp_proto(xauthdir, sizeof(xauthdir));
339 if (mkdtemp(xauthdir) == NULL) {
340 error_f("mkdtemp: %s", strerror(errno));
344 if ((r = snprintf(xauthfile, sizeof(xauthfile),
345 "%s/xauthfile", xauthdir)) < 0 ||
346 (size_t)r >= sizeof(xauthfile)) {
347 error_f("xauthfile path too long");
353 /* auth doesn't time out */
354 xasprintf(&cmd, "%s -f %s generate %s %s "
356 xauth_path, xauthfile, display,
357 SSH_X11_PROTO, _PATH_DEVNULL);
359 /* Add some slack to requested expiry */
360 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK)
361 x11_timeout_real = timeout +
364 /* Don't overflow on long timeouts */
365 x11_timeout_real = UINT_MAX;
367 xasprintf(&cmd, "%s -f %s generate %s %s "
368 "untrusted timeout %u 2>%s",
369 xauth_path, xauthfile, display,
370 SSH_X11_PROTO, x11_timeout_real,
373 debug2_f("xauth command: %s", cmd);
375 if (timeout != 0 && x11_refuse_time == 0) {
376 now = monotime() + 1;
377 if (SSH_TIME_T_MAX - timeout < now)
378 x11_refuse_time = SSH_TIME_T_MAX;
380 x11_refuse_time = now + timeout;
381 channel_set_x11_refuse_time(ssh,
384 if (system(cmd) == 0)
390 * When in untrusted mode, we read the cookie only if it was
391 * successfully generated as an untrusted one in the step
394 if (trusted || generated) {
396 "%s %s%s list %s 2>" _PATH_DEVNULL,
398 generated ? "-f " : "" ,
399 generated ? xauthfile : "",
401 debug2("x11_get_proto: %s", cmd);
403 if (f && fgets(line, sizeof(line), f) &&
404 sscanf(line, "%*s %511s %511s", proto, data) == 2)
417 /* Don't fall back to fake X11 data for untrusted forwarding */
418 if (!trusted && !got_data) {
419 error("Warning: untrusted X11 forwarding setup failed: "
420 "xauth key data not generated");
425 * If we didn't get authentication data, just make up some
426 * data. The forwarding code will check the validity of the
427 * response anyway, and substitute this data. The X11
428 * server, however, will ignore this fake data and use
429 * whatever authentication mechanisms it was using otherwise
430 * for the local connection.
436 logit("Warning: No xauth data; "
437 "using fake authentication data for X11 forwarding.");
438 strlcpy(proto, SSH_X11_PROTO, sizeof proto);
439 arc4random_buf(rnd, sizeof(rnd));
440 for (i = 0; i < sizeof(rnd); i++) {
441 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x",
450 * Checks if the client window has changed, and sends a packet about it to
451 * the server if so. The actual change is detected elsewhere (by a software
452 * interrupt on Unix); this just checks the flag and sends a message if
457 client_check_window_change(struct ssh *ssh)
459 if (!received_window_change_signal)
461 received_window_change_signal = 0;
463 channel_send_window_changes(ssh);
467 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh)
469 struct global_confirm *gc;
471 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL)
474 gc->cb(ssh, type, seq, gc->ctx);
475 if (--gc->ref_count <= 0) {
476 TAILQ_REMOVE(&global_confirms, gc, entry);
477 freezero(gc, sizeof(*gc));
480 ssh_packet_set_alive_timeouts(ssh, 0);
485 schedule_server_alive_check(void)
487 if (options.server_alive_interval > 0)
488 server_alive_time = monotime() + options.server_alive_interval;
492 server_alive_check(struct ssh *ssh)
496 if (ssh_packet_inc_alive_timeouts(ssh) > options.server_alive_count_max) {
497 logit("Timeout, server %s not responding.", host);
500 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
501 (r = sshpkt_put_cstring(ssh, "keepalive@openssh.com")) != 0 ||
502 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* boolean: want reply */
503 (r = sshpkt_send(ssh)) != 0)
504 fatal_fr(r, "send packet");
505 /* Insert an empty placeholder to maintain ordering */
506 client_register_global_confirm(NULL, NULL);
507 schedule_server_alive_check();
511 * Waits until the client can do something (some data becomes available on
512 * one of the file descriptors).
515 client_wait_until_can_do_something(struct ssh *ssh, struct pollfd **pfdp,
516 u_int *npfd_allocp, u_int *npfd_activep, int rekeying,
517 int *conn_in_readyp, int *conn_out_readyp)
519 struct timespec timeout;
523 *conn_in_readyp = *conn_out_readyp = 0;
525 /* Prepare channel poll. First two pollfd entries are reserved */
526 ptimeout_init(&timeout);
527 channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, 2, &timeout);
528 if (*npfd_activep < 2)
529 fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */
531 /* channel_prepare_poll could have closed the last channel */
532 if (session_closed && !channel_still_open(ssh) &&
533 !ssh_packet_have_data_to_write(ssh)) {
534 /* clear events since we did not call poll() */
535 for (p = 0; p < *npfd_activep; p++)
536 (*pfdp)[p].revents = 0;
540 /* Monitor server connection on reserved pollfd entries */
541 (*pfdp)[0].fd = connection_in;
542 (*pfdp)[0].events = POLLIN;
543 (*pfdp)[1].fd = connection_out;
544 (*pfdp)[1].events = ssh_packet_have_data_to_write(ssh) ? POLLOUT : 0;
547 * Wait for something to happen. This will suspend the process until
548 * some polled descriptor can be read, written, or has some other
549 * event pending, or a timeout expires.
551 set_control_persist_exit_time(ssh);
552 if (control_persist_exit_time > 0)
553 ptimeout_deadline_monotime(&timeout, control_persist_exit_time);
554 if (options.server_alive_interval > 0)
555 ptimeout_deadline_monotime(&timeout, server_alive_time);
556 if (options.rekey_interval > 0 && !rekeying) {
557 ptimeout_deadline_sec(&timeout,
558 ssh_packet_get_rekey_timeout(ssh));
561 ret = poll(*pfdp, *npfd_activep, ptimeout_get_ms(&timeout));
565 * We have to clear the events because we return.
566 * We have to return, because the mainloop checks for the flags
567 * set by the signal handlers.
569 for (p = 0; p < *npfd_activep; p++)
570 (*pfdp)[p].revents = 0;
573 /* Note: we might still have data in the buffers. */
574 quit_message("poll: %s", strerror(errno));
578 *conn_in_readyp = (*pfdp)[0].revents != 0;
579 *conn_out_readyp = (*pfdp)[1].revents != 0;
581 if (options.server_alive_interval > 0 && !*conn_in_readyp &&
582 monotime() >= server_alive_time) {
584 * ServerAlive check is needed. We can't rely on the poll
585 * timing out since traffic on the client side such as port
586 * forwards can keep waking it up.
588 server_alive_check(ssh);
593 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr)
595 /* Flush stdout and stderr buffers. */
596 if (sshbuf_len(bout) > 0)
597 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout),
599 if (sshbuf_len(berr) > 0)
600 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr),
603 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
609 /* Send the suspend signal to the program itself. */
610 kill(getpid(), SIGTSTP);
612 /* Reset window sizes in case they have changed */
613 received_window_change_signal = 1;
615 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
619 client_process_net_input(struct ssh *ssh)
624 * Read input from the server, and add any such data to the buffer of
625 * the packet subsystem.
627 schedule_server_alive_check();
628 if ((r = ssh_packet_process_read(ssh, connection_in)) == 0)
629 return; /* success */
630 if (r == SSH_ERR_SYSTEM_ERROR) {
631 if (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)
633 if (errno == EPIPE) {
634 quit_message("Connection to %s closed by remote host.",
639 quit_message("Read from remote host %s: %s", host, ssh_err(r));
643 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx)
645 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx;
650 * If a TTY was explicitly requested, then a failure to allocate
653 if (cr->action == CONFIRM_TTY &&
654 (options.request_tty == REQUEST_TTY_FORCE ||
655 options.request_tty == REQUEST_TTY_YES))
656 cr->action = CONFIRM_CLOSE;
658 /* XXX suppress on mux _client_ quietmode */
659 tochan = options.log_level >= SYSLOG_LEVEL_ERROR &&
660 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE;
662 if (type == SSH2_MSG_CHANNEL_SUCCESS) {
663 debug2("%s request accepted on channel %d",
664 cr->request_type, c->self);
665 } else if (type == SSH2_MSG_CHANNEL_FAILURE) {
667 snprintf(errmsg, sizeof(errmsg),
668 "%s request failed\r\n", cr->request_type);
670 snprintf(errmsg, sizeof(errmsg),
671 "%s request failed on channel %d",
672 cr->request_type, c->self);
674 /* If error occurred on primary session channel, then exit */
675 if (cr->action == CONFIRM_CLOSE && c->self == session_ident)
678 * If error occurred on mux client, append to
682 debug3_f("channel %d: mux request: %s", c->self,
684 if ((r = sshbuf_put(c->extended, errmsg,
685 strlen(errmsg))) != 0)
686 fatal_fr(r, "sshbuf_put");
689 if (cr->action == CONFIRM_TTY) {
691 * If a TTY allocation error occurred, then arrange
692 * for the correct TTY to leave raw mode.
694 if (c->self == session_ident)
697 mux_tty_alloc_failed(ssh, c);
698 } else if (cr->action == CONFIRM_CLOSE) {
699 chan_read_failed(ssh, c);
700 chan_write_failed(ssh, c);
707 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx)
713 client_expect_confirm(struct ssh *ssh, int id, const char *request,
714 enum confirm_action action)
716 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr));
718 cr->request_type = request;
721 channel_register_status_confirm(ssh, id, client_status_confirm,
722 client_abandon_status_confirm, cr);
726 client_register_global_confirm(global_confirm_cb *cb, void *ctx)
728 struct global_confirm *gc, *last_gc;
730 /* Coalesce identical callbacks */
731 last_gc = TAILQ_LAST(&global_confirms, global_confirms);
732 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) {
733 if (++last_gc->ref_count >= INT_MAX)
734 fatal_f("last_gc->ref_count = %d",
739 gc = xcalloc(1, sizeof(*gc));
743 TAILQ_INSERT_TAIL(&global_confirms, gc, entry);
747 * Returns non-zero if the client is able to handle a hostkeys-00@openssh.com
748 * hostkey update request.
751 can_update_hostkeys(void)
753 if (hostkeys_update_complete)
755 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK &&
757 return 0; /* won't ask in batchmode, so don't even try */
758 if (!options.update_hostkeys || options.num_user_hostfiles <= 0)
764 client_repledge(void)
768 /* Might be able to tighten pledge now that session is established */
769 if (options.control_master || options.control_path != NULL ||
770 options.forward_x11 || options.fork_after_authentication ||
771 can_update_hostkeys() ||
772 (session_ident != -1 && !session_setup_complete)) {
777 * LocalCommand and UpdateHostkeys have finished, so can get rid of
780 * XXX protocol allows a server can to change hostkeys during the
781 * connection at rekey time that could trigger a hostkeys update
782 * but AFAIK no implementations support this. Could improve by
783 * forcing known_hosts to be read-only or via unveil(2).
785 if (options.num_local_forwards != 0 ||
786 options.num_remote_forwards != 0 ||
787 options.num_permitted_remote_opens != 0 ||
788 options.enable_escape_commandline != 0) {
789 /* rfwd needs inet */
790 debug("pledge: network");
791 if (pledge("stdio unix inet dns proc tty", NULL) == -1)
792 fatal_f("pledge(): %s", strerror(errno));
793 } else if (options.forward_agent != 0) {
794 /* agent forwarding needs to open $SSH_AUTH_SOCK at will */
795 debug("pledge: agent");
796 if (pledge("stdio unix proc tty", NULL) == -1)
797 fatal_f("pledge(): %s", strerror(errno));
799 debug("pledge: fork");
800 if (pledge("stdio proc tty", NULL) == -1)
801 fatal_f("pledge(): %s", strerror(errno));
803 /* XXX further things to do:
805 * - might be able to get rid of proc if we kill ~^Z
806 * - ssh -N (no session)
808 * - sessions without tty
813 process_cmdline(struct ssh *ssh)
815 void (*handler)(int);
817 int ok, delete = 0, local = 0, remote = 0, dynamic = 0;
820 memset(&fwd, 0, sizeof(fwd));
822 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
823 handler = ssh_signal(SIGINT, SIG_IGN);
824 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO);
827 while (isspace((u_char)*s))
830 s++; /* Skip cmdline '-', if any */
834 if (*s == 'h' || *s == 'H' || *s == '?') {
836 logit(" -L[bind_address:]port:host:hostport "
837 "Request local forward");
838 logit(" -R[bind_address:]port:host:hostport "
839 "Request remote forward");
840 logit(" -D[bind_address:]port "
841 "Request dynamic forward");
842 logit(" -KL[bind_address:]port "
843 "Cancel local forward");
844 logit(" -KR[bind_address:]port "
845 "Cancel remote forward");
846 logit(" -KD[bind_address:]port "
847 "Cancel dynamic forward");
848 if (!options.permit_local_command)
851 "Execute local command");
855 if (*s == '!' && options.permit_local_command) {
872 logit("Invalid command.");
876 while (isspace((u_char)*++s))
879 /* XXX update list of forwards in options */
881 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */
882 if (!parse_forward(&fwd, s, 1, 0)) {
883 logit("Bad forwarding close specification.");
887 ok = channel_request_rforward_cancel(ssh, &fwd) == 0;
889 ok = channel_cancel_lport_listener(ssh, &fwd,
890 0, &options.fwd_opts) > 0;
892 ok = channel_cancel_lport_listener(ssh, &fwd,
893 CHANNEL_CANCEL_PORT_STATIC,
894 &options.fwd_opts) > 0;
896 logit("Unknown port forwarding.");
899 logit("Canceled forwarding.");
901 /* -R specs can be both dynamic or not, so check both. */
903 if (!parse_forward(&fwd, s, 0, remote) &&
904 !parse_forward(&fwd, s, 1, remote)) {
905 logit("Bad remote forwarding specification.");
908 } else if (!parse_forward(&fwd, s, dynamic, remote)) {
909 logit("Bad local forwarding specification.");
912 if (local || dynamic) {
913 if (!channel_setup_local_fwd_listener(ssh, &fwd,
914 &options.fwd_opts)) {
915 logit("Port forwarding failed.");
919 if (channel_request_remote_forwarding(ssh, &fwd) < 0) {
920 logit("Port forwarding failed.");
924 logit("Forwarding port.");
928 ssh_signal(SIGINT, handler);
929 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
931 free(fwd.listen_host);
932 free(fwd.listen_path);
933 free(fwd.connect_host);
934 free(fwd.connect_path);
937 /* reasons to suppress output of an escape command in help output */
938 #define SUPPRESS_NEVER 0 /* never suppress, always show */
939 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */
940 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */
941 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */
942 #define SUPPRESS_NOCMDLINE 8 /* don't show when cmdline disabled*/
943 struct escape_help_text {
948 static struct escape_help_text esc_txt[] = {
949 {".", "terminate session", SUPPRESS_MUXMASTER},
950 {".", "terminate connection (and any multiplexed sessions)",
952 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER},
953 {"C", "open a command line", SUPPRESS_MUXCLIENT|SUPPRESS_NOCMDLINE},
954 {"R", "request rekey", SUPPRESS_NEVER},
955 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT},
956 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT},
957 {"#", "list forwarded connections", SUPPRESS_NEVER},
958 {"&", "background ssh (when waiting for connections to terminate)",
960 {"?", "this message", SUPPRESS_NEVER},
964 print_escape_help(struct sshbuf *b, int escape_char, int mux_client,
967 unsigned int i, suppress_flags;
970 if ((r = sshbuf_putf(b,
971 "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0)
972 fatal_fr(r, "sshbuf_putf");
975 (mux_client ? SUPPRESS_MUXCLIENT : 0) |
976 (mux_client ? 0 : SUPPRESS_MUXMASTER) |
977 (using_stderr ? 0 : SUPPRESS_SYSLOG) |
978 (options.enable_escape_commandline == 0 ? SUPPRESS_NOCMDLINE : 0);
980 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) {
981 if (esc_txt[i].flags & suppress_flags)
983 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n",
984 escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0)
985 fatal_fr(r, "sshbuf_putf");
988 if ((r = sshbuf_putf(b,
989 " %c%c - send the escape character by typing it twice\r\n"
990 "(Note that escapes are only recognized immediately after "
991 "newline.)\r\n", escape_char, escape_char)) != 0)
992 fatal_fr(r, "sshbuf_putf");
996 * Process the characters one by one.
999 process_escapes(struct ssh *ssh, Channel *c,
1000 struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr,
1008 struct escape_filter_ctx *efc;
1010 if (c == NULL || c->filter_ctx == NULL || len <= 0)
1013 efc = (struct escape_filter_ctx *)c->filter_ctx;
1015 for (i = 0; i < (u_int)len; i++) {
1016 /* Get one character at a time. */
1019 if (efc->escape_pending) {
1020 /* We have previously seen an escape character. */
1021 /* Clear the flag now. */
1022 efc->escape_pending = 0;
1024 /* Process the escaped character. */
1027 /* Terminate the connection. */
1028 if ((r = sshbuf_putf(berr, "%c.\r\n",
1029 efc->escape_char)) != 0)
1030 fatal_fr(r, "sshbuf_putf");
1031 if (c && c->ctl_chan != -1) {
1032 channel_force_close(ssh, c, 1);
1039 /* XXX support this for mux clients */
1040 if (c && c->ctl_chan != -1) {
1044 snprintf(b, sizeof b, "^Z");
1046 snprintf(b, sizeof b, "%c", ch);
1047 if ((r = sshbuf_putf(berr,
1048 "%c%s escape not available to "
1049 "multiplexed sessions\r\n",
1050 efc->escape_char, b)) != 0)
1051 fatal_fr(r, "sshbuf_putf");
1054 /* Suspend the program. Inform the user */
1055 if ((r = sshbuf_putf(berr,
1056 "%c^Z [suspend ssh]\r\n",
1057 efc->escape_char)) != 0)
1058 fatal_fr(r, "sshbuf_putf");
1060 /* Restore terminal modes and suspend. */
1061 client_suspend_self(bin, bout, berr);
1063 /* We have been continued. */
1067 if ((r = sshbuf_putf(berr,
1068 "%cB\r\n", efc->escape_char)) != 0)
1069 fatal_fr(r, "sshbuf_putf");
1070 channel_request_start(ssh, c->self, "break", 0);
1071 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 ||
1072 (r = sshpkt_send(ssh)) != 0)
1073 fatal_fr(r, "send packet");
1077 if (ssh->compat & SSH_BUG_NOREKEY)
1078 logit("Server does not "
1079 "support re-keying");
1087 if (c && c->ctl_chan != -1)
1089 if (!log_is_on_stderr()) {
1090 if ((r = sshbuf_putf(berr,
1091 "%c%c [Logging to syslog]\r\n",
1092 efc->escape_char, ch)) != 0)
1093 fatal_fr(r, "sshbuf_putf");
1096 if (ch == 'V' && options.log_level >
1098 log_change_level(--options.log_level);
1099 if (ch == 'v' && options.log_level <
1100 SYSLOG_LEVEL_DEBUG3)
1101 log_change_level(++options.log_level);
1102 if ((r = sshbuf_putf(berr,
1103 "%c%c [LogLevel %s]\r\n",
1104 efc->escape_char, ch,
1105 log_level_name(options.log_level))) != 0)
1106 fatal_fr(r, "sshbuf_putf");
1110 if (c->ctl_chan != -1)
1113 * Detach the program (continue to serve
1114 * connections, but put in background and no
1115 * more new connections).
1117 /* Restore tty modes. */
1119 options.request_tty == REQUEST_TTY_FORCE);
1121 /* Stop listening for new connections. */
1122 channel_stop_listening(ssh);
1124 if ((r = sshbuf_putf(berr, "%c& "
1125 "[backgrounded]\n", efc->escape_char)) != 0)
1126 fatal_fr(r, "sshbuf_putf");
1128 /* Fork into background. */
1131 error("fork: %.100s", strerror(errno));
1134 if (pid != 0) { /* This is the parent. */
1135 /* The parent just exits. */
1138 /* The child continues serving connections. */
1139 /* fake EOF on stdin */
1140 if ((r = sshbuf_put_u8(bin, 4)) != 0)
1141 fatal_fr(r, "sshbuf_put_u8");
1144 print_escape_help(berr, efc->escape_char,
1145 (c && c->ctl_chan != -1),
1146 log_is_on_stderr());
1150 if ((r = sshbuf_putf(berr, "%c#\r\n",
1151 efc->escape_char)) != 0)
1152 fatal_fr(r, "sshbuf_putf");
1153 s = channel_open_message(ssh);
1154 if ((r = sshbuf_put(berr, s, strlen(s))) != 0)
1155 fatal_fr(r, "sshbuf_put");
1160 if (c && c->ctl_chan != -1)
1162 if (options.enable_escape_commandline == 0) {
1163 if ((r = sshbuf_putf(berr,
1164 "commandline disabled\r\n")) != 0)
1165 fatal_fr(r, "sshbuf_putf");
1168 process_cmdline(ssh);
1172 if (ch != efc->escape_char) {
1173 if ((r = sshbuf_put_u8(bin,
1174 efc->escape_char)) != 0)
1175 fatal_fr(r, "sshbuf_put_u8");
1178 /* Escaped characters fall through here */
1183 * The previous character was not an escape char.
1184 * Check if this is an escape.
1186 if (last_was_cr && ch == efc->escape_char) {
1188 * It is. Set the flag and continue to
1191 efc->escape_pending = 1;
1197 * Normal character. Record whether it was a newline,
1198 * and append it to the buffer.
1200 last_was_cr = (ch == '\r' || ch == '\n');
1201 if ((r = sshbuf_put_u8(bin, ch)) != 0)
1202 fatal_fr(r, "sshbuf_put_u8");
1209 * Get packets from the connection input buffer, and process them as long as
1210 * there are packets available.
1212 * Any unknown packets received during the actual
1213 * session cause the session to terminate. This is
1214 * intended to make debugging easier since no
1215 * confirmations are sent. Any compatible protocol
1216 * extensions must be negotiated during the
1217 * preparatory phase.
1221 client_process_buffered_input_packets(struct ssh *ssh)
1223 ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, &quit_pending);
1226 /* scan buf[] for '~' before sending data to the peer */
1228 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */
1230 client_new_escape_filter_ctx(int escape_char)
1232 struct escape_filter_ctx *ret;
1234 ret = xcalloc(1, sizeof(*ret));
1235 ret->escape_pending = 0;
1236 ret->escape_char = escape_char;
1240 /* Free the escape filter context on channel free */
1242 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx)
1248 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len)
1250 if (c->extended_usage != CHAN_EXTENDED_WRITE)
1253 return process_escapes(ssh, c, c->input, c->output, c->extended,
1258 client_channel_closed(struct ssh *ssh, int id, int force, void *arg)
1260 channel_cancel_cleanup(ssh, id);
1262 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1266 * Implements the interactive session with the server. This is called after
1267 * the user has been authenticated, and a command has been started on the
1268 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character
1269 * used as an escape character for terminating or suspending the session.
1272 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg,
1275 struct pollfd *pfd = NULL;
1276 u_int npfd_alloc = 0, npfd_active = 0;
1277 double start_time, total_time;
1279 u_int64_t ibytes, obytes;
1280 int conn_in_ready, conn_out_ready;
1282 debug("Entering interactive session.");
1283 session_ident = ssh2_chan_id;
1285 if (options.control_master &&
1286 !option_clear_or_none(options.control_path)) {
1287 debug("pledge: id");
1288 if (pledge("stdio rpath wpath cpath unix inet dns recvfd sendfd proc exec id tty",
1290 fatal_f("pledge(): %s", strerror(errno));
1292 } else if (options.forward_x11 || options.permit_local_command) {
1293 debug("pledge: exec");
1294 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty",
1296 fatal_f("pledge(): %s", strerror(errno));
1298 } else if (options.update_hostkeys) {
1299 debug("pledge: filesystem");
1300 if (pledge("stdio rpath wpath cpath unix inet dns proc tty",
1302 fatal_f("pledge(): %s", strerror(errno));
1304 } else if (!option_clear_or_none(options.proxy_command) ||
1305 options.fork_after_authentication) {
1306 debug("pledge: proc");
1307 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1)
1308 fatal_f("pledge(): %s", strerror(errno));
1311 debug("pledge: network");
1312 if (pledge("stdio unix inet dns proc tty", NULL) == -1)
1313 fatal_f("pledge(): %s", strerror(errno));
1316 /* might be able to tighten now */
1319 start_time = monotime_double();
1321 /* Initialize variables. */
1324 connection_in = ssh_packet_get_connection_in(ssh);
1325 connection_out = ssh_packet_get_connection_out(ssh);
1329 /* Initialize buffer. */
1330 if ((stderr_buffer = sshbuf_new()) == NULL)
1331 fatal_f("sshbuf_new failed");
1333 client_init_dispatch(ssh);
1336 * Set signal handlers, (e.g. to restore non-blocking mode)
1337 * but don't overwrite SIG_IGN, matches behaviour from rsh(1)
1339 if (ssh_signal(SIGHUP, SIG_IGN) != SIG_IGN)
1340 ssh_signal(SIGHUP, signal_handler);
1341 if (ssh_signal(SIGINT, SIG_IGN) != SIG_IGN)
1342 ssh_signal(SIGINT, signal_handler);
1343 if (ssh_signal(SIGQUIT, SIG_IGN) != SIG_IGN)
1344 ssh_signal(SIGQUIT, signal_handler);
1345 if (ssh_signal(SIGTERM, SIG_IGN) != SIG_IGN)
1346 ssh_signal(SIGTERM, signal_handler);
1347 ssh_signal(SIGWINCH, window_change_handler);
1350 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1352 if (session_ident != -1) {
1353 if (escape_char_arg != SSH_ESCAPECHAR_NONE) {
1354 channel_register_filter(ssh, session_ident,
1355 client_simple_escape_filter, NULL,
1356 client_filter_cleanup,
1357 client_new_escape_filter_ctx(
1360 channel_register_cleanup(ssh, session_ident,
1361 client_channel_closed, 0);
1364 schedule_server_alive_check();
1366 /* Main loop of the client for the interactive session mode. */
1367 while (!quit_pending) {
1369 /* Process buffered packets sent by the server. */
1370 client_process_buffered_input_packets(ssh);
1372 if (session_closed && !channel_still_open(ssh))
1375 if (ssh_packet_is_rekeying(ssh)) {
1376 debug("rekeying in progress");
1377 } else if (need_rekeying) {
1378 /* manual rekey request */
1379 debug("need rekeying");
1380 if ((r = kex_start_rekex(ssh)) != 0)
1381 fatal_fr(r, "kex_start_rekex");
1385 * Make packets from buffered channel data, and
1386 * enqueue them for sending to the server.
1388 if (ssh_packet_not_very_much_data_to_write(ssh))
1389 channel_output_poll(ssh);
1392 * Check if the window size has changed, and buffer a
1393 * message about it to the server if so.
1395 client_check_window_change(ssh);
1401 * Wait until we have something to do (something becomes
1402 * available on one of the descriptors).
1404 client_wait_until_can_do_something(ssh, &pfd, &npfd_alloc,
1405 &npfd_active, ssh_packet_is_rekeying(ssh),
1406 &conn_in_ready, &conn_out_ready);
1411 /* Do channel operations. */
1412 channel_after_poll(ssh, pfd, npfd_active);
1414 /* Buffer input from the connection. */
1416 client_process_net_input(ssh);
1421 /* A timeout may have triggered rekeying */
1422 if ((r = ssh_packet_check_rekey(ssh)) != 0)
1423 fatal_fr(r, "cannot start rekeying");
1426 * Send as much buffered packet data as possible to the
1429 if (conn_out_ready) {
1430 if ((r = ssh_packet_write_poll(ssh)) != 0) {
1431 sshpkt_fatal(ssh, r,
1432 "%s: ssh_packet_write_poll", __func__);
1437 * If we are a backgrounded control master, and the
1438 * timeout has expired without any active client
1439 * connections, then quit.
1441 if (control_persist_exit_time > 0) {
1442 if (monotime() >= control_persist_exit_time) {
1443 debug("ControlPersist timeout expired");
1450 /* Terminate the session. */
1452 /* Stop watching for window change. */
1453 ssh_signal(SIGWINCH, SIG_DFL);
1455 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
1456 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_BY_APPLICATION)) != 0 ||
1457 (r = sshpkt_put_cstring(ssh, "disconnected by user")) != 0 ||
1458 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* language tag */
1459 (r = sshpkt_send(ssh)) != 0 ||
1460 (r = ssh_packet_write_wait(ssh)) != 0)
1461 fatal_fr(r, "send disconnect");
1463 channel_free_all(ssh);
1466 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1469 * If there was no shell or command requested, there will be no remote
1470 * exit status to be returned. In that case, clear error code if the
1471 * connection was deliberately terminated at this end.
1473 if (options.session_type == SESSION_TYPE_NONE &&
1474 received_signal == SIGTERM) {
1475 received_signal = 0;
1479 if (received_signal) {
1480 verbose("Killed by signal %d.", (int) received_signal);
1485 * In interactive mode (with pseudo tty) display a message indicating
1486 * that the connection has been closed.
1488 if (have_pty && options.log_level >= SYSLOG_LEVEL_INFO)
1489 quit_message("Connection to %s closed.", host);
1491 /* Output any buffered data for stderr. */
1492 if (sshbuf_len(stderr_buffer) > 0) {
1493 len = atomicio(vwrite, fileno(stderr),
1494 (u_char *)sshbuf_ptr(stderr_buffer),
1495 sshbuf_len(stderr_buffer));
1496 if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer))
1497 error("Write failed flushing stderr buffer.");
1498 else if ((r = sshbuf_consume(stderr_buffer, len)) != 0)
1499 fatal_fr(r, "sshbuf_consume");
1502 /* Clear and free any buffers. */
1503 sshbuf_free(stderr_buffer);
1505 /* Report bytes transferred, and transfer rates. */
1506 total_time = monotime_double() - start_time;
1507 ssh_packet_get_bytes(ssh, &ibytes, &obytes);
1508 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds",
1509 (unsigned long long)obytes, (unsigned long long)ibytes, total_time);
1511 verbose("Bytes per second: sent %.1f, received %.1f",
1512 obytes / total_time, ibytes / total_time);
1513 /* Return the exit status of the program. */
1514 debug("Exit status %d", exit_status);
1521 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type,
1522 int rchan, u_int rwindow, u_int rmaxpack)
1525 struct sshbuf *b = NULL;
1526 char *listen_address, *originator_address;
1527 u_int listen_port, originator_port;
1530 /* Get rest of the packet */
1531 if ((r = sshpkt_get_cstring(ssh, &listen_address, NULL)) != 0 ||
1532 (r = sshpkt_get_u32(ssh, &listen_port)) != 0 ||
1533 (r = sshpkt_get_cstring(ssh, &originator_address, NULL)) != 0 ||
1534 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 ||
1535 (r = sshpkt_get_end(ssh)) != 0)
1536 fatal_fr(r, "parse packet");
1538 debug_f("listen %s port %d, originator %s port %d",
1539 listen_address, listen_port, originator_address, originator_port);
1541 if (listen_port > 0xffff)
1542 error_f("invalid listen port");
1543 else if (originator_port > 0xffff)
1544 error_f("invalid originator port");
1546 c = channel_connect_by_listen_address(ssh,
1547 listen_address, listen_port, "forwarded-tcpip",
1548 originator_address);
1551 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
1552 if ((b = sshbuf_new()) == NULL) {
1553 error_f("alloc reply");
1556 /* reconstruct and send to muxclient */
1557 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */
1558 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
1559 (r = sshbuf_put_cstring(b, request_type)) != 0 ||
1560 (r = sshbuf_put_u32(b, rchan)) != 0 ||
1561 (r = sshbuf_put_u32(b, rwindow)) != 0 ||
1562 (r = sshbuf_put_u32(b, rmaxpack)) != 0 ||
1563 (r = sshbuf_put_cstring(b, listen_address)) != 0 ||
1564 (r = sshbuf_put_u32(b, listen_port)) != 0 ||
1565 (r = sshbuf_put_cstring(b, originator_address)) != 0 ||
1566 (r = sshbuf_put_u32(b, originator_port)) != 0 ||
1567 (r = sshbuf_put_stringb(c->output, b)) != 0) {
1568 error_fr(r, "compose for muxclient");
1575 free(originator_address);
1576 free(listen_address);
1581 client_request_forwarded_streamlocal(struct ssh *ssh,
1582 const char *request_type, int rchan)
1588 /* Get the remote path. */
1589 if ((r = sshpkt_get_cstring(ssh, &listen_path, NULL)) != 0 ||
1590 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* reserved */
1591 (r = sshpkt_get_end(ssh)) != 0)
1592 fatal_fr(r, "parse packet");
1594 debug_f("request: %s", listen_path);
1596 c = channel_connect_by_listen_path(ssh, listen_path,
1597 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal");
1603 client_request_x11(struct ssh *ssh, const char *request_type, int rchan)
1607 u_int originator_port;
1610 if (!options.forward_x11) {
1611 error("Warning: ssh server tried X11 forwarding.");
1612 error("Warning: this is probably a break-in attempt by a "
1613 "malicious server.");
1616 if (x11_refuse_time != 0 && monotime() >= x11_refuse_time) {
1617 verbose("Rejected X11 connection after ForwardX11Timeout "
1621 if ((r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 ||
1622 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 ||
1623 (r = sshpkt_get_end(ssh)) != 0)
1624 fatal_fr(r, "parse packet");
1625 /* XXX check permission */
1626 /* XXX range check originator port? */
1627 debug("client_request_x11: request from %s %u", originator,
1630 sock = x11_connect_display(ssh);
1633 c = channel_new(ssh, "x11",
1634 SSH_CHANNEL_X11_OPEN, sock, sock, -1,
1635 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1);
1641 client_request_agent(struct ssh *ssh, const char *request_type, int rchan)
1646 if (!options.forward_agent) {
1647 error("Warning: ssh server tried agent forwarding.");
1648 error("Warning: this is probably a break-in attempt by a "
1649 "malicious server.");
1652 if (forward_agent_sock_path == NULL) {
1653 r = ssh_get_authentication_socket(&sock);
1655 r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock);
1658 if (r != SSH_ERR_AGENT_NOT_PRESENT)
1659 debug_fr(r, "ssh_get_authentication_socket");
1662 if ((r = ssh_agent_bind_hostkey(sock, ssh->kex->initial_hostkey,
1663 ssh->kex->session_id, ssh->kex->initial_sig, 1)) == 0)
1664 debug_f("bound agent to hostkey");
1666 debug2_fr(r, "ssh_agent_bind_hostkey");
1668 c = channel_new(ssh, "authentication agent connection",
1669 SSH_CHANNEL_OPEN, sock, sock, -1,
1670 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0,
1671 "authentication agent connection", 1);
1677 client_request_tun_fwd(struct ssh *ssh, int tun_mode,
1678 int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx)
1682 char *ifname = NULL;
1684 if (tun_mode == SSH_TUNMODE_NO)
1687 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode);
1689 /* Open local tunnel device */
1690 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) {
1691 error("Tunnel device open failed.");
1694 debug("Tunnel forwarding using interface %s", ifname);
1696 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1,
1697 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1);
1700 #if defined(SSH_TUN_FILTER)
1701 if (options.tun_open == SSH_TUNMODE_POINTOPOINT)
1702 channel_register_filter(ssh, c->self, sys_tun_infilter,
1703 sys_tun_outfilter, NULL, NULL);
1707 channel_register_open_confirm(ssh, c->self, cb, cbctx);
1709 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
1710 (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 ||
1711 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
1712 (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 ||
1713 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 ||
1714 (r = sshpkt_put_u32(ssh, tun_mode)) != 0 ||
1715 (r = sshpkt_put_u32(ssh, remote_tun)) != 0 ||
1716 (r = sshpkt_send(ssh)) != 0)
1717 sshpkt_fatal(ssh, r, "%s: send reply", __func__);
1722 /* XXXX move to generic input handler */
1724 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh)
1731 u_int rmaxpack, rwindow;
1733 if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 ||
1734 (r = sshpkt_get_u32(ssh, &rchan)) != 0 ||
1735 (r = sshpkt_get_u32(ssh, &rwindow)) != 0 ||
1736 (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0)
1739 debug("client_input_channel_open: ctype %s rchan %d win %d max %d",
1740 ctype, rchan, rwindow, rmaxpack);
1742 if (strcmp(ctype, "forwarded-tcpip") == 0) {
1743 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow,
1745 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) {
1746 c = client_request_forwarded_streamlocal(ssh, ctype, rchan);
1747 } else if (strcmp(ctype, "x11") == 0) {
1748 c = client_request_x11(ssh, ctype, rchan);
1749 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) {
1750 c = client_request_agent(ssh, ctype, rchan);
1752 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) {
1753 debug3("proxied to downstream: %s", ctype);
1754 } else if (c != NULL) {
1755 debug("confirm %s", ctype);
1756 c->remote_id = rchan;
1757 c->have_remote_id = 1;
1758 c->remote_window = rwindow;
1759 c->remote_maxpacket = rmaxpack;
1760 if (c->type != SSH_CHANNEL_CONNECTING) {
1761 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 ||
1762 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1763 (r = sshpkt_put_u32(ssh, c->self)) != 0 ||
1764 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
1765 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 ||
1766 (r = sshpkt_send(ssh)) != 0)
1767 sshpkt_fatal(ssh, r, "%s: send reply", __func__);
1770 debug("failure %s", ctype);
1771 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 ||
1772 (r = sshpkt_put_u32(ssh, rchan)) != 0 ||
1773 (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 ||
1774 (r = sshpkt_put_cstring(ssh, "open failed")) != 0 ||
1775 (r = sshpkt_put_cstring(ssh, "")) != 0 ||
1776 (r = sshpkt_send(ssh)) != 0)
1777 sshpkt_fatal(ssh, r, "%s: send failure", __func__);
1786 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh)
1794 if ((r = sshpkt_get_u32(ssh, &id)) != 0)
1797 c = channel_lookup(ssh, id);
1798 if (channel_proxy_upstream(c, type, seq, ssh))
1800 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 ||
1801 (r = sshpkt_get_u8(ssh, &reply)) != 0)
1804 debug("client_input_channel_req: channel %u rtype %s reply %d",
1808 error("client_input_channel_req: channel %d: "
1809 "unknown channel", id);
1810 } else if (strcmp(rtype, "eow@openssh.com") == 0) {
1811 if ((r = sshpkt_get_end(ssh)) != 0)
1813 chan_rcvd_eow(ssh, c);
1814 } else if (strcmp(rtype, "exit-status") == 0) {
1815 if ((r = sshpkt_get_u32(ssh, &exitval)) != 0)
1817 if (c->ctl_chan != -1) {
1818 mux_exit_message(ssh, c, exitval);
1820 } else if ((int)id == session_ident) {
1821 /* Record exit value of local session */
1823 exit_status = exitval;
1825 /* Probably for a mux channel that has already closed */
1826 debug_f("no sink for exit-status on channel %d",
1829 if ((r = sshpkt_get_end(ssh)) != 0)
1832 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) {
1833 if (!c->have_remote_id)
1834 fatal_f("channel %d: no remote_id", c->self);
1835 if ((r = sshpkt_start(ssh, success ?
1836 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 ||
1837 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
1838 (r = sshpkt_send(ssh)) != 0)
1839 sshpkt_fatal(ssh, r, "%s: send failure", __func__);
1847 struct hostkeys_update_ctx {
1848 /* The hostname and (optionally) IP address string for the server */
1849 char *host_str, *ip_str;
1852 * Keys received from the server and a flag for each indicating
1853 * whether they already exist in known_hosts.
1854 * keys_match is filled in by hostkeys_find() and later (for new
1855 * keys) by client_global_hostkeys_prove_confirm().
1857 struct sshkey **keys;
1858 u_int *keys_match; /* mask of HKF_MATCH_* from hostfile.h */
1859 int *keys_verified; /* flag for new keys verified by server */
1860 size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */
1863 * Keys that are in known_hosts, but were not present in the update
1864 * from the server (i.e. scheduled to be deleted).
1865 * Filled in by hostkeys_find().
1867 struct sshkey **old_keys;
1870 /* Various special cases. */
1871 int complex_hostspec; /* wildcard or manual pattern-list host name */
1872 int ca_available; /* saw CA key for this host */
1873 int old_key_seen; /* saw old key with other name/addr */
1874 int other_name_seen; /* saw key with other name/addr */
1878 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx)
1884 for (i = 0; i < ctx->nkeys; i++)
1885 sshkey_free(ctx->keys[i]);
1887 free(ctx->keys_match);
1888 free(ctx->keys_verified);
1889 for (i = 0; i < ctx->nold; i++)
1890 sshkey_free(ctx->old_keys[i]);
1891 free(ctx->old_keys);
1892 free(ctx->host_str);
1898 * Returns non-zero if a known_hosts hostname list is not of a form that
1899 * can be handled by UpdateHostkeys. These include wildcard hostnames and
1900 * hostnames lists that do not follow the form host[,ip].
1903 hostspec_is_complex(const char *hosts)
1908 if (strchr(hosts, '*') != NULL || strchr(hosts, '?') != NULL)
1910 /* single host/ip = ok */
1911 if ((cp = strchr(hosts, ',')) == NULL)
1913 /* more than two entries on the line */
1914 if (strchr(cp + 1, ',') != NULL)
1916 /* XXX maybe parse cp+1 and ensure it is an IP? */
1920 /* callback to search for ctx->keys in known_hosts */
1922 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx)
1924 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
1926 struct sshkey **tmp;
1930 if (l->status != HKF_STATUS_MATCHED) {
1931 /* Record if one of the keys appears on a non-matching line */
1932 for (i = 0; i < ctx->nkeys; i++) {
1933 if (sshkey_equal(l->key, ctx->keys[i])) {
1934 ctx->other_name_seen = 1;
1935 debug3_f("found %s key under different "
1936 "name/addr at %s:%ld",
1937 sshkey_ssh_name(ctx->keys[i]),
1938 l->path, l->linenum);
1944 /* Don't proceed if revocation or CA markers are present */
1945 /* XXX relax this */
1946 if (l->marker != MRK_NONE) {
1947 debug3_f("hostkeys file %s:%ld has CA/revocation marker",
1948 l->path, l->linenum);
1949 ctx->complex_hostspec = 1;
1953 /* If CheckHostIP is enabled, then check for mismatched hostname/addr */
1954 if (ctx->ip_str != NULL && strchr(l->hosts, ',') != NULL) {
1955 if ((l->match & HKF_MATCH_HOST) == 0) {
1956 /* Record if address matched a different hostname. */
1957 ctx->other_name_seen = 1;
1958 debug3_f("found address %s against different hostname "
1959 "at %s:%ld", ctx->ip_str, l->path, l->linenum);
1961 } else if ((l->match & HKF_MATCH_IP) == 0) {
1962 /* Record if hostname matched a different address. */
1963 ctx->other_name_seen = 1;
1964 debug3_f("found hostname %s against different address "
1965 "at %s:%ld", ctx->host_str, l->path, l->linenum);
1970 * UpdateHostkeys is skipped for wildcard host names and hostnames
1971 * that contain more than two entries (ssh never writes these).
1973 if (hostspec_is_complex(l->hosts)) {
1974 debug3_f("hostkeys file %s:%ld complex host specification",
1975 l->path, l->linenum);
1976 ctx->complex_hostspec = 1;
1980 /* Mark off keys we've already seen for this host */
1981 for (i = 0; i < ctx->nkeys; i++) {
1982 if (!sshkey_equal(l->key, ctx->keys[i]))
1984 debug3_f("found %s key at %s:%ld",
1985 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum);
1986 ctx->keys_match[i] |= l->match;
1989 /* This line contained a key that not offered by the server */
1990 debug3_f("deprecated %s key at %s:%ld", sshkey_ssh_name(l->key),
1991 l->path, l->linenum);
1992 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1,
1993 sizeof(*ctx->old_keys))) == NULL)
1994 fatal_f("recallocarray failed nold = %zu", ctx->nold);
1995 ctx->old_keys = tmp;
1996 ctx->old_keys[ctx->nold++] = l->key;
2002 /* callback to search for ctx->old_keys in known_hosts under other names */
2004 hostkeys_check_old(struct hostkey_foreach_line *l, void *_ctx)
2006 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
2010 /* only care about lines that *don't* match the active host spec */
2011 if (l->status == HKF_STATUS_MATCHED || l->key == NULL)
2014 hashed = l->match & (HKF_MATCH_HOST_HASHED|HKF_MATCH_IP_HASHED);
2015 for (i = 0; i < ctx->nold; i++) {
2016 if (!sshkey_equal(l->key, ctx->old_keys[i]))
2018 debug3_f("found deprecated %s key at %s:%ld as %s",
2019 sshkey_ssh_name(ctx->old_keys[i]), l->path, l->linenum,
2020 hashed ? "[HASHED]" : l->hosts);
2021 ctx->old_key_seen = 1;
2028 * Check known_hosts files for deprecated keys under other names. Returns 0
2029 * on success or -1 on failure. Updates ctx->old_key_seen if deprecated keys
2030 * exist under names other than the active hostname/IP.
2033 check_old_keys_othernames(struct hostkeys_update_ctx *ctx)
2038 debug2_f("checking for %zu deprecated keys", ctx->nold);
2039 for (i = 0; i < options.num_user_hostfiles; i++) {
2040 debug3_f("searching %s for %s / %s",
2041 options.user_hostfiles[i], ctx->host_str,
2042 ctx->ip_str ? ctx->ip_str : "(none)");
2043 if ((r = hostkeys_foreach(options.user_hostfiles[i],
2044 hostkeys_check_old, ctx, ctx->host_str, ctx->ip_str,
2045 HKF_WANT_PARSE_KEY, 0)) != 0) {
2046 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
2047 debug_f("hostkeys file %s does not exist",
2048 options.user_hostfiles[i]);
2051 error_fr(r, "hostkeys_foreach failed for %s",
2052 options.user_hostfiles[i]);
2060 hostkey_change_preamble(LogLevel loglevel)
2062 do_log2(loglevel, "The server has updated its host keys.");
2063 do_log2(loglevel, "These changes were verified by the server's "
2064 "existing trusted key.");
2068 update_known_hosts(struct hostkeys_update_ctx *ctx)
2070 int r, was_raw = 0, first = 1;
2071 int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK;
2072 LogLevel loglevel = asking ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE;
2073 char *fp, *response;
2077 for (i = 0; i < ctx->nkeys; i++) {
2078 if (!ctx->keys_verified[i])
2080 if ((fp = sshkey_fingerprint(ctx->keys[i],
2081 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
2082 fatal_f("sshkey_fingerprint failed");
2083 if (first && asking)
2084 hostkey_change_preamble(loglevel);
2085 do_log2(loglevel, "Learned new hostkey: %s %s",
2086 sshkey_type(ctx->keys[i]), fp);
2090 for (i = 0; i < ctx->nold; i++) {
2091 if ((fp = sshkey_fingerprint(ctx->old_keys[i],
2092 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
2093 fatal_f("sshkey_fingerprint failed");
2094 if (first && asking)
2095 hostkey_change_preamble(loglevel);
2096 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s",
2097 sshkey_type(ctx->old_keys[i]), fp);
2101 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) {
2102 if (get_saved_tio() != NULL) {
2107 for (i = 0; !quit_pending && i < 3; i++) {
2109 response = read_passphrase("Accept updated hostkeys? "
2110 "(yes/no): ", RP_ECHO);
2111 if (response != NULL && strcasecmp(response, "yes") == 0)
2113 else if (quit_pending || response == NULL ||
2114 strcasecmp(response, "no") == 0) {
2115 options.update_hostkeys = 0;
2118 do_log2(loglevel, "Please enter "
2119 "\"yes\" or \"no\"");
2122 if (quit_pending || i >= 3 || response == NULL)
2123 options.update_hostkeys = 0;
2128 if (options.update_hostkeys == 0)
2131 * Now that all the keys are verified, we can go ahead and replace
2132 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't
2133 * cancel the operation).
2135 for (i = 0; i < options.num_user_hostfiles; i++) {
2137 * NB. keys are only added to hostfiles[0], for the rest we
2138 * just delete the hostname entries.
2140 if (stat(options.user_hostfiles[i], &sb) != 0) {
2141 if (errno == ENOENT) {
2142 debug_f("known hosts file %s does not "
2143 "exist", options.user_hostfiles[i]);
2145 error_f("known hosts file %s "
2147 options.user_hostfiles[i], strerror(errno));
2151 if ((r = hostfile_replace_entries(options.user_hostfiles[i],
2152 ctx->host_str, ctx->ip_str,
2153 i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0,
2154 options.hash_known_hosts, 0,
2155 options.fingerprint_hash)) != 0) {
2156 error_fr(r, "hostfile_replace_entries failed for %s",
2157 options.user_hostfiles[i]);
2163 client_global_hostkeys_prove_confirm(struct ssh *ssh, int type,
2164 u_int32_t seq, void *_ctx)
2166 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
2168 struct sshbuf *signdata;
2171 const char *rsa_kexalg = NULL;
2176 fatal_f("ctx->nnew == 0"); /* sanity */
2177 if (type != SSH2_MSG_REQUEST_SUCCESS) {
2178 error("Server failed to confirm ownership of "
2179 "private host keys");
2180 hostkeys_update_ctx_free(ctx);
2183 if (sshkey_type_plain(sshkey_type_from_name(
2184 ssh->kex->hostkey_alg)) == KEY_RSA)
2185 rsa_kexalg = ssh->kex->hostkey_alg;
2186 if ((signdata = sshbuf_new()) == NULL)
2187 fatal_f("sshbuf_new failed");
2189 * Expect a signature for each of the ctx->nnew private keys we
2190 * haven't seen before. They will be in the same order as the
2191 * ctx->keys where the corresponding ctx->keys_match[i] == 0.
2193 for (ndone = i = 0; i < ctx->nkeys; i++) {
2194 if (ctx->keys_match[i])
2196 plaintype = sshkey_type_plain(ctx->keys[i]->type);
2197 /* Prepare data to be signed: session ID, unique string, key */
2198 sshbuf_reset(signdata);
2199 if ( (r = sshbuf_put_cstring(signdata,
2200 "hostkeys-prove-00@openssh.com")) != 0 ||
2201 (r = sshbuf_put_stringb(signdata,
2202 ssh->kex->session_id)) != 0 ||
2203 (r = sshkey_puts(ctx->keys[i], signdata)) != 0)
2204 fatal_fr(r, "compose signdata");
2205 /* Extract and verify signature */
2206 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) {
2207 error_fr(r, "parse sig");
2210 if ((r = sshkey_get_sigtype(sig, siglen, &alg)) != 0) {
2211 error_fr(r, "server gave unintelligible signature "
2212 "for %s key %zu", sshkey_type(ctx->keys[i]), i);
2216 * Special case for RSA keys: if a RSA hostkey was negotiated,
2217 * then use its signature type for verification of RSA hostkey
2218 * proofs. Otherwise, accept only RSA-SHA256/512 signatures.
2220 if (plaintype == KEY_RSA && rsa_kexalg == NULL &&
2221 match_pattern_list(alg, HOSTKEY_PROOF_RSA_ALGS, 0) != 1) {
2222 debug_f("server used untrusted RSA signature algorithm "
2223 "%s for key %zu, disregarding", alg, i);
2225 /* zap the key from the list */
2226 sshkey_free(ctx->keys[i]);
2227 ctx->keys[i] = NULL;
2231 debug3_f("verify %s key %zu using sigalg %s",
2232 sshkey_type(ctx->keys[i]), i, alg);
2234 if ((r = sshkey_verify(ctx->keys[i], sig, siglen,
2235 sshbuf_ptr(signdata), sshbuf_len(signdata),
2236 plaintype == KEY_RSA ? rsa_kexalg : NULL, 0, NULL)) != 0) {
2237 error_fr(r, "server gave bad signature for %s key %zu",
2238 sshkey_type(ctx->keys[i]), i);
2241 /* Key is good. Mark it as 'seen' */
2242 ctx->keys_verified[i] = 1;
2245 /* Shouldn't happen */
2246 if (ndone != ctx->nnew)
2247 fatal_f("ndone != ctx->nnew (%zu / %zu)", ndone, ctx->nnew);
2248 if ((r = sshpkt_get_end(ssh)) != 0) {
2249 error_f("protocol error");
2253 /* Make the edits to known_hosts */
2254 update_known_hosts(ctx);
2256 hostkeys_update_ctx_free(ctx);
2257 hostkeys_update_complete = 1;
2262 * Returns non-zero if the key is accepted by HostkeyAlgorithms.
2263 * Made slightly less trivial by the multiple RSA signature algorithm names.
2266 key_accepted_by_hostkeyalgs(const struct sshkey *key)
2268 const char *ktype = sshkey_ssh_name(key);
2269 const char *hostkeyalgs = options.hostkeyalgorithms;
2271 if (key->type == KEY_UNSPEC)
2273 if (key->type == KEY_RSA &&
2274 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 ||
2275 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1))
2277 return match_pattern_list(ktype, hostkeyalgs, 0) == 1;
2281 * Handle hostkeys-00@openssh.com global request to inform the client of all
2282 * the server's hostkeys. The keys are checked against the user's
2283 * HostkeyAlgorithms preference before they are accepted.
2286 client_input_hostkeys(struct ssh *ssh)
2288 const u_char *blob = NULL;
2290 struct sshbuf *buf = NULL;
2291 struct sshkey *key = NULL, **tmp;
2292 int r, prove_sent = 0;
2294 static int hostkeys_seen = 0; /* XXX use struct ssh */
2295 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */
2296 struct hostkeys_update_ctx *ctx = NULL;
2300 fatal_f("server already sent hostkeys");
2301 if (!can_update_hostkeys())
2305 ctx = xcalloc(1, sizeof(*ctx));
2306 while (ssh_packet_remaining(ssh) > 0) {
2309 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) {
2310 error_fr(r, "parse key");
2313 if ((r = sshkey_from_blob(blob, len, &key)) != 0) {
2314 do_log2_fr(r, r == SSH_ERR_KEY_TYPE_UNKNOWN ?
2315 SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR,
2319 fp = sshkey_fingerprint(key, options.fingerprint_hash,
2321 debug3_f("received %s key %s", sshkey_type(key), fp);
2324 if (!key_accepted_by_hostkeyalgs(key)) {
2325 debug3_f("%s key not permitted by "
2326 "HostkeyAlgorithms", sshkey_ssh_name(key));
2330 if (sshkey_is_cert(key)) {
2331 debug3_f("%s key is a certificate; skipping",
2332 sshkey_ssh_name(key));
2335 /* Ensure keys are unique */
2336 for (i = 0; i < ctx->nkeys; i++) {
2337 if (sshkey_equal(key, ctx->keys[i])) {
2338 error_f("received duplicated %s host key",
2339 sshkey_ssh_name(key));
2343 /* Key is good, record it */
2344 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1,
2345 sizeof(*ctx->keys))) == NULL)
2346 fatal_f("recallocarray failed nkeys = %zu",
2349 ctx->keys[ctx->nkeys++] = key;
2353 if (ctx->nkeys == 0) {
2354 debug_f("server sent no hostkeys");
2358 if ((ctx->keys_match = calloc(ctx->nkeys,
2359 sizeof(*ctx->keys_match))) == NULL ||
2360 (ctx->keys_verified = calloc(ctx->nkeys,
2361 sizeof(*ctx->keys_verified))) == NULL)
2362 fatal_f("calloc failed");
2364 get_hostfile_hostname_ipaddr(host,
2365 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL,
2366 options.port, &ctx->host_str,
2367 options.check_host_ip ? &ctx->ip_str : NULL);
2369 /* Find which keys we already know about. */
2370 for (i = 0; i < options.num_user_hostfiles; i++) {
2371 debug_f("searching %s for %s / %s",
2372 options.user_hostfiles[i], ctx->host_str,
2373 ctx->ip_str ? ctx->ip_str : "(none)");
2374 if ((r = hostkeys_foreach(options.user_hostfiles[i],
2375 hostkeys_find, ctx, ctx->host_str, ctx->ip_str,
2376 HKF_WANT_PARSE_KEY, 0)) != 0) {
2377 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
2378 debug_f("hostkeys file %s does not exist",
2379 options.user_hostfiles[i]);
2382 error_fr(r, "hostkeys_foreach failed for %s",
2383 options.user_hostfiles[i]);
2388 /* Figure out if we have any new keys to add */
2389 ctx->nnew = ctx->nincomplete = 0;
2390 want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0);
2391 for (i = 0; i < ctx->nkeys; i++) {
2392 if (ctx->keys_match[i] == 0)
2394 if ((ctx->keys_match[i] & want) != want)
2398 debug3_f("%zu server keys: %zu new, %zu retained, "
2399 "%zu incomplete match. %zu to remove", ctx->nkeys, ctx->nnew,
2400 ctx->nkeys - ctx->nnew - ctx->nincomplete,
2401 ctx->nincomplete, ctx->nold);
2403 if (ctx->nnew == 0 && ctx->nold == 0) {
2404 debug_f("no new or deprecated keys from server");
2408 /* Various reasons why we cannot proceed with the update */
2409 if (ctx->complex_hostspec) {
2410 debug_f("CA/revocation marker, manual host list or wildcard "
2411 "host pattern found, skipping UserKnownHostsFile update");
2414 if (ctx->other_name_seen) {
2415 debug_f("host key found matching a different name/address, "
2416 "skipping UserKnownHostsFile update");
2420 * If removing keys, check whether they appear under different
2421 * names/addresses and refuse to proceed if they do. This avoids
2422 * cases such as hosts with multiple names becoming inconsistent
2423 * with regards to CheckHostIP entries.
2424 * XXX UpdateHostkeys=force to override this (and other) checks?
2426 if (ctx->nold != 0) {
2427 if (check_old_keys_othernames(ctx) != 0)
2428 goto out; /* error already logged */
2429 if (ctx->old_key_seen) {
2430 debug_f("key(s) for %s%s%s exist under other names; "
2431 "skipping UserKnownHostsFile update",
2432 ctx->host_str, ctx->ip_str == NULL ? "" : ",",
2433 ctx->ip_str == NULL ? "" : ctx->ip_str);
2438 if (ctx->nnew == 0) {
2440 * We have some keys to remove or fix matching for.
2441 * We can proceed to do this without requiring a fresh proof
2444 update_known_hosts(ctx);
2448 * We have received previously-unseen keys from the server.
2449 * Ask the server to confirm ownership of the private halves.
2451 debug3_f("asking server to prove ownership for %zu keys", ctx->nnew);
2452 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
2453 (r = sshpkt_put_cstring(ssh,
2454 "hostkeys-prove-00@openssh.com")) != 0 ||
2455 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */
2456 fatal_fr(r, "prepare hostkeys-prove");
2457 if ((buf = sshbuf_new()) == NULL)
2458 fatal_f("sshbuf_new");
2459 for (i = 0; i < ctx->nkeys; i++) {
2460 if (ctx->keys_match[i])
2463 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0 ||
2464 (r = sshpkt_put_stringb(ssh, buf)) != 0)
2465 fatal_fr(r, "assemble hostkeys-prove");
2467 if ((r = sshpkt_send(ssh)) != 0)
2468 fatal_fr(r, "send hostkeys-prove");
2469 client_register_global_confirm(
2470 client_global_hostkeys_prove_confirm, ctx);
2471 ctx = NULL; /* will be freed in callback */
2476 hostkeys_update_ctx_free(ctx);
2480 /* UpdateHostkeys handling completed */
2481 hostkeys_update_complete = 1;
2485 * NB. Return success for all cases. The server doesn't need to know
2486 * what the client does with its hosts file.
2492 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh)
2498 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 ||
2499 (r = sshpkt_get_u8(ssh, &want_reply)) != 0)
2501 debug("client_input_global_request: rtype %s want_reply %d",
2503 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0)
2504 success = client_input_hostkeys(ssh);
2506 if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS :
2507 SSH2_MSG_REQUEST_FAILURE)) != 0 ||
2508 (r = sshpkt_send(ssh)) != 0 ||
2509 (r = ssh_packet_write_wait(ssh)) != 0)
2519 client_send_env(struct ssh *ssh, int id, const char *name, const char *val)
2523 debug("channel %d: setting env %s = \"%s\"", id, name, val);
2524 channel_request_start(ssh, id, "env", 0);
2525 if ((r = sshpkt_put_cstring(ssh, name)) != 0 ||
2526 (r = sshpkt_put_cstring(ssh, val)) != 0 ||
2527 (r = sshpkt_send(ssh)) != 0)
2528 fatal_fr(r, "send setenv");
2532 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem,
2533 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd,
2541 debug2_f("id %d", id);
2543 if ((c = channel_lookup(ssh, id)) == NULL)
2544 fatal_f("channel %d: unknown channel", id);
2546 ssh_packet_set_interactive(ssh, want_tty,
2547 options.ip_qos_interactive, options.ip_qos_bulk);
2552 /* Store window size in the packet. */
2553 if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1)
2554 memset(&ws, 0, sizeof(ws));
2556 channel_request_start(ssh, id, "pty-req", 1);
2557 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY);
2558 if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : ""))
2560 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 ||
2561 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 ||
2562 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 ||
2563 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0)
2564 fatal_fr(r, "build pty-req");
2566 tiop = get_saved_tio();
2567 ssh_tty_make_modes(ssh, -1, tiop);
2568 if ((r = sshpkt_send(ssh)) != 0)
2569 fatal_fr(r, "send pty-req");
2570 /* XXX wait for reply */
2574 /* Transfer any environment variables from client to server */
2575 if (options.num_send_env != 0 && env != NULL) {
2576 debug("Sending environment.");
2577 for (i = 0; env[i] != NULL; i++) {
2579 name = xstrdup(env[i]);
2580 if ((val = strchr(name, '=')) == NULL) {
2587 for (j = 0; j < options.num_send_env; j++) {
2588 if (match_pattern(name, options.send_env[j])) {
2594 debug3("Ignored env %s", name);
2598 client_send_env(ssh, id, name, val);
2602 for (i = 0; i < options.num_setenv; i++) {
2604 name = xstrdup(options.setenv[i]);
2605 if ((val = strchr(name, '=')) == NULL) {
2610 client_send_env(ssh, id, name, val);
2614 len = sshbuf_len(cmd);
2618 if (want_subsystem) {
2619 debug("Sending subsystem: %.*s",
2620 (int)len, (const u_char*)sshbuf_ptr(cmd));
2621 channel_request_start(ssh, id, "subsystem", 1);
2622 client_expect_confirm(ssh, id, "subsystem",
2625 debug("Sending command: %.*s",
2626 (int)len, (const u_char*)sshbuf_ptr(cmd));
2627 channel_request_start(ssh, id, "exec", 1);
2628 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE);
2630 if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 ||
2631 (r = sshpkt_send(ssh)) != 0)
2632 fatal_fr(r, "send command");
2634 channel_request_start(ssh, id, "shell", 1);
2635 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE);
2636 if ((r = sshpkt_send(ssh)) != 0)
2637 fatal_fr(r, "send shell");
2640 session_setup_complete = 1;
2645 client_init_dispatch(struct ssh *ssh)
2647 ssh_dispatch_init(ssh, &dispatch_protocol_error);
2649 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose);
2650 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data);
2651 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof);
2652 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data);
2653 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open);
2654 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation);
2655 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure);
2656 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req);
2657 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust);
2658 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm);
2659 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm);
2660 ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request);
2663 ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit);
2665 /* global request reply messages */
2666 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply);
2667 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply);
2671 client_stop_mux(void)
2673 if (options.control_path != NULL && muxserver_sock != -1)
2674 unlink(options.control_path);
2676 * If we are in persist mode, or don't have a shell, signal that we
2677 * should close when all active channels are closed.
2679 if (options.control_persist || options.session_type == SESSION_TYPE_NONE) {
2681 setproctitle("[stopped mux]");
2685 /* client specific fatal cleanup */
2689 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
2690 if (options.control_path != NULL && muxserver_sock != -1)
2691 unlink(options.control_path);
2692 ssh_kill_proxy_command();