1 /* $OpenBSD: mux.c,v 1.50 2015/01/20 23:14:00 deraadt Exp $ */
3 * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org>
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 /* ssh session multiplexing support */
22 * - Better signalling from master to slave, especially passing of
24 * - Better fall-back from mux slave error to new connection.
25 * - ExitOnForwardingFailure
26 * - Maybe extension mechanisms for multi-X11/multi-agent forwarding
27 * - Support ~^Z in mux slaves.
28 * - Inspect or control sessions in master.
29 * - If we ever support the "signal" channel request, send signals on
35 #include <sys/types.h>
37 #include <sys/socket.h>
56 # ifdef HAVE_SYS_POLL_H
57 # include <sys/poll.h>
65 #include "openbsd-compat/sys-queue.h"
70 #include "pathnames.h"
77 #include "monitor_fdpass.h"
81 #include "clientloop.h"
85 extern Options options;
86 extern int stdin_null_flag;
88 extern int subsystem_flag;
89 extern Buffer command;
90 extern volatile sig_atomic_t quit_pending;
91 extern char *stdio_forward_host;
92 extern int stdio_forward_port;
94 /* Context for session open confirmation callback */
95 struct mux_session_confirm_ctx {
107 /* Context for stdio fwd open confirmation callback */
108 struct mux_stdio_confirm_ctx {
112 /* Context for global channel callback */
113 struct mux_channel_confirm_ctx {
114 u_int cid; /* channel id */
115 u_int rid; /* request id */
116 int fid; /* forward id */
119 /* fd to control socket */
120 int muxserver_sock = -1;
122 /* client request id */
123 u_int muxclient_request_id = 0;
125 /* Multiplexing control command */
126 u_int muxclient_command = 0;
128 /* Set when signalled. */
129 static volatile sig_atomic_t muxclient_terminate = 0;
131 /* PID of multiplex server */
132 static u_int muxserver_pid = 0;
134 static Channel *mux_listener_channel = NULL;
136 struct mux_master_state {
140 /* mux protocol messages */
141 #define MUX_MSG_HELLO 0x00000001
142 #define MUX_C_NEW_SESSION 0x10000002
143 #define MUX_C_ALIVE_CHECK 0x10000004
144 #define MUX_C_TERMINATE 0x10000005
145 #define MUX_C_OPEN_FWD 0x10000006
146 #define MUX_C_CLOSE_FWD 0x10000007
147 #define MUX_C_NEW_STDIO_FWD 0x10000008
148 #define MUX_C_STOP_LISTENING 0x10000009
149 #define MUX_S_OK 0x80000001
150 #define MUX_S_PERMISSION_DENIED 0x80000002
151 #define MUX_S_FAILURE 0x80000003
152 #define MUX_S_EXIT_MESSAGE 0x80000004
153 #define MUX_S_ALIVE 0x80000005
154 #define MUX_S_SESSION_OPENED 0x80000006
155 #define MUX_S_REMOTE_PORT 0x80000007
156 #define MUX_S_TTY_ALLOC_FAIL 0x80000008
158 /* type codes for MUX_C_OPEN_FWD and MUX_C_CLOSE_FWD */
159 #define MUX_FWD_LOCAL 1
160 #define MUX_FWD_REMOTE 2
161 #define MUX_FWD_DYNAMIC 3
163 static void mux_session_confirm(int, int, void *);
164 static void mux_stdio_confirm(int, int, void *);
166 static int process_mux_master_hello(u_int, Channel *, Buffer *, Buffer *);
167 static int process_mux_new_session(u_int, Channel *, Buffer *, Buffer *);
168 static int process_mux_alive_check(u_int, Channel *, Buffer *, Buffer *);
169 static int process_mux_terminate(u_int, Channel *, Buffer *, Buffer *);
170 static int process_mux_open_fwd(u_int, Channel *, Buffer *, Buffer *);
171 static int process_mux_close_fwd(u_int, Channel *, Buffer *, Buffer *);
172 static int process_mux_stdio_fwd(u_int, Channel *, Buffer *, Buffer *);
173 static int process_mux_stop_listening(u_int, Channel *, Buffer *, Buffer *);
175 static const struct {
177 int (*handler)(u_int, Channel *, Buffer *, Buffer *);
178 } mux_master_handlers[] = {
179 { MUX_MSG_HELLO, process_mux_master_hello },
180 { MUX_C_NEW_SESSION, process_mux_new_session },
181 { MUX_C_ALIVE_CHECK, process_mux_alive_check },
182 { MUX_C_TERMINATE, process_mux_terminate },
183 { MUX_C_OPEN_FWD, process_mux_open_fwd },
184 { MUX_C_CLOSE_FWD, process_mux_close_fwd },
185 { MUX_C_NEW_STDIO_FWD, process_mux_stdio_fwd },
186 { MUX_C_STOP_LISTENING, process_mux_stop_listening },
190 /* Cleanup callback fired on closure of mux slave _session_ channel */
193 mux_master_session_cleanup_cb(int cid, void *unused)
195 Channel *cc, *c = channel_by_id(cid);
197 debug3("%s: entering for channel %d", __func__, cid);
199 fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
200 if (c->ctl_chan != -1) {
201 if ((cc = channel_by_id(c->ctl_chan)) == NULL)
202 fatal("%s: channel %d missing control channel %d",
203 __func__, c->self, c->ctl_chan);
206 chan_rcvd_oclose(cc);
208 channel_cancel_cleanup(c->self);
211 /* Cleanup callback fired on closure of mux slave _control_ channel */
214 mux_master_control_cleanup_cb(int cid, void *unused)
216 Channel *sc, *c = channel_by_id(cid);
218 debug3("%s: entering for channel %d", __func__, cid);
220 fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
221 if (c->remote_id != -1) {
222 if ((sc = channel_by_id(c->remote_id)) == NULL)
223 fatal("%s: channel %d missing session channel %d",
224 __func__, c->self, c->remote_id);
227 if (sc->type != SSH_CHANNEL_OPEN &&
228 sc->type != SSH_CHANNEL_OPENING) {
229 debug2("%s: channel %d: not open", __func__, sc->self);
232 if (sc->istate == CHAN_INPUT_OPEN)
233 chan_read_failed(sc);
234 if (sc->ostate == CHAN_OUTPUT_OPEN)
235 chan_write_failed(sc);
238 channel_cancel_cleanup(c->self);
241 /* Check mux client environment variables before passing them to mux master. */
243 env_permitted(char *env)
246 char name[1024], *cp;
248 if ((cp = strchr(env, '=')) == NULL || cp == env)
250 ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
251 if (ret <= 0 || (size_t)ret >= sizeof(name)) {
252 error("env_permitted: name '%.100s...' too long", env);
256 for (i = 0; i < options.num_send_env; i++)
257 if (match_pattern(name, options.send_env[i]))
263 /* Mux master protocol message handlers */
266 process_mux_master_hello(u_int rid, Channel *c, Buffer *m, Buffer *r)
269 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
272 fatal("%s: channel %d: c->mux_ctx == NULL", __func__, c->self);
273 if (state->hello_rcvd) {
274 error("%s: HELLO received twice", __func__);
277 if (buffer_get_int_ret(&ver, m) != 0) {
279 error("%s: malformed message", __func__);
282 if (ver != SSHMUX_VER) {
283 error("Unsupported multiplexing protocol version %d "
284 "(expected %d)", ver, SSHMUX_VER);
287 debug2("%s: channel %d slave version %u", __func__, c->self, ver);
289 /* No extensions are presently defined */
290 while (buffer_len(m) > 0) {
291 char *name = buffer_get_string_ret(m, NULL);
292 char *value = buffer_get_string_ret(m, NULL);
294 if (name == NULL || value == NULL) {
299 debug2("Unrecognised slave extension \"%s\"", name);
303 state->hello_rcvd = 1;
308 process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r)
311 struct mux_session_confirm_ctx *cctx;
312 char *reserved, *cmd, *cp;
313 u_int i, j, len, env_len, escape_char, window, packetmax;
316 /* Reply for SSHMUX_COMMAND_OPEN */
317 cctx = xcalloc(1, sizeof(*cctx));
320 cmd = reserved = NULL;
323 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
324 buffer_get_int_ret(&cctx->want_tty, m) != 0 ||
325 buffer_get_int_ret(&cctx->want_x_fwd, m) != 0 ||
326 buffer_get_int_ret(&cctx->want_agent_fwd, m) != 0 ||
327 buffer_get_int_ret(&cctx->want_subsys, m) != 0 ||
328 buffer_get_int_ret(&escape_char, m) != 0 ||
329 (cctx->term = buffer_get_string_ret(m, &len)) == NULL ||
330 (cmd = buffer_get_string_ret(m, &len)) == NULL) {
334 for (j = 0; j < env_len; j++)
339 error("%s: malformed message", __func__);
345 while (buffer_len(m) > 0) {
346 #define MUX_MAX_ENV_VARS 4096
347 if ((cp = buffer_get_string_ret(m, &len)) == NULL)
349 if (!env_permitted(cp)) {
353 cctx->env = xrealloc(cctx->env, env_len + 2,
355 cctx->env[env_len++] = cp;
356 cctx->env[env_len] = NULL;
357 if (env_len > MUX_MAX_ENV_VARS) {
358 error(">%d environment variables received, ignoring "
359 "additional", MUX_MAX_ENV_VARS);
364 debug2("%s: channel %d: request tty %d, X %d, agent %d, subsys %d, "
365 "term \"%s\", cmd \"%s\", env %u", __func__, c->self,
366 cctx->want_tty, cctx->want_x_fwd, cctx->want_agent_fwd,
367 cctx->want_subsys, cctx->term, cmd, env_len);
369 buffer_init(&cctx->cmd);
370 buffer_append(&cctx->cmd, cmd, strlen(cmd));
374 /* Gather fds from client */
375 for(i = 0; i < 3; i++) {
376 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
377 error("%s: failed to receive fd %d from slave",
379 for (j = 0; j < i; j++)
381 for (j = 0; j < env_len; j++)
385 buffer_free(&cctx->cmd);
389 buffer_put_int(r, MUX_S_FAILURE);
390 buffer_put_int(r, rid);
391 buffer_put_cstring(r,
392 "did not receive file descriptors");
397 debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
398 new_fd[0], new_fd[1], new_fd[2]);
400 /* XXX support multiple child sessions in future */
401 if (c->remote_id != -1) {
402 debug2("%s: session already open", __func__);
404 buffer_put_int(r, MUX_S_FAILURE);
405 buffer_put_int(r, rid);
406 buffer_put_cstring(r, "Multiple sessions not supported");
413 for (i = 0; i < env_len; i++)
417 buffer_free(&cctx->cmd);
422 if (options.control_master == SSHCTL_MASTER_ASK ||
423 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
424 if (!ask_permission("Allow shared connection to %s? ", host)) {
425 debug2("%s: session refused by user", __func__);
427 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
428 buffer_put_int(r, rid);
429 buffer_put_cstring(r, "Permission denied");
434 /* Try to pick up ttymodes from client before it goes raw */
435 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
436 error("%s: tcgetattr: %s", __func__, strerror(errno));
438 /* enable nonblocking unless tty */
439 if (!isatty(new_fd[0]))
440 set_nonblock(new_fd[0]);
441 if (!isatty(new_fd[1]))
442 set_nonblock(new_fd[1]);
443 if (!isatty(new_fd[2]))
444 set_nonblock(new_fd[2]);
446 window = CHAN_SES_WINDOW_DEFAULT;
447 packetmax = CHAN_SES_PACKET_DEFAULT;
448 if (cctx->want_tty) {
453 nc = channel_new("session", SSH_CHANNEL_OPENING,
454 new_fd[0], new_fd[1], new_fd[2], window, packetmax,
455 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
457 nc->ctl_chan = c->self; /* link session -> control channel */
458 c->remote_id = nc->self; /* link control -> session channel */
460 if (cctx->want_tty && escape_char != 0xffffffff) {
461 channel_register_filter(nc->self,
462 client_simple_escape_filter, NULL,
463 client_filter_cleanup,
464 client_new_escape_filter_ctx((int)escape_char));
467 debug2("%s: channel_new: %d linked to control channel %d",
468 __func__, nc->self, nc->ctl_chan);
470 channel_send_open(nc->self);
471 channel_register_open_confirm(nc->self, mux_session_confirm, cctx);
472 c->mux_pause = 1; /* stop handling messages until open_confirm done */
473 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
475 /* reply is deferred, sent by mux_session_confirm */
480 process_mux_alive_check(u_int rid, Channel *c, Buffer *m, Buffer *r)
482 debug2("%s: channel %d: alive check", __func__, c->self);
485 buffer_put_int(r, MUX_S_ALIVE);
486 buffer_put_int(r, rid);
487 buffer_put_int(r, (u_int)getpid());
493 process_mux_terminate(u_int rid, Channel *c, Buffer *m, Buffer *r)
495 debug2("%s: channel %d: terminate request", __func__, c->self);
497 if (options.control_master == SSHCTL_MASTER_ASK ||
498 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
499 if (!ask_permission("Terminate shared connection to %s? ",
501 debug2("%s: termination refused by user", __func__);
502 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
503 buffer_put_int(r, rid);
504 buffer_put_cstring(r, "Permission denied");
510 buffer_put_int(r, MUX_S_OK);
511 buffer_put_int(r, rid);
512 /* XXX exit happens too soon - message never makes it to client */
517 format_forward(u_int ftype, struct Forward *fwd)
523 xasprintf(&ret, "local forward %.200s:%d -> %.200s:%d",
524 (fwd->listen_path != NULL) ? fwd->listen_path :
525 (fwd->listen_host == NULL) ?
526 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
527 fwd->listen_host, fwd->listen_port,
528 (fwd->connect_path != NULL) ? fwd->connect_path :
529 fwd->connect_host, fwd->connect_port);
531 case MUX_FWD_DYNAMIC:
532 xasprintf(&ret, "dynamic forward %.200s:%d -> *",
533 (fwd->listen_host == NULL) ?
534 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
535 fwd->listen_host, fwd->listen_port);
538 xasprintf(&ret, "remote forward %.200s:%d -> %.200s:%d",
539 (fwd->listen_path != NULL) ? fwd->listen_path :
540 (fwd->listen_host == NULL) ?
541 "LOCALHOST" : fwd->listen_host,
543 (fwd->connect_path != NULL) ? fwd->connect_path :
544 fwd->connect_host, fwd->connect_port);
547 fatal("%s: unknown forward type %u", __func__, ftype);
553 compare_host(const char *a, const char *b)
555 if (a == NULL && b == NULL)
557 if (a == NULL || b == NULL)
559 return strcmp(a, b) == 0;
563 compare_forward(struct Forward *a, struct Forward *b)
565 if (!compare_host(a->listen_host, b->listen_host))
567 if (!compare_host(a->listen_path, b->listen_path))
569 if (a->listen_port != b->listen_port)
571 if (!compare_host(a->connect_host, b->connect_host))
573 if (!compare_host(a->connect_path, b->connect_path))
575 if (a->connect_port != b->connect_port)
582 mux_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
584 struct mux_channel_confirm_ctx *fctx = ctxt;
585 char *failmsg = NULL;
586 struct Forward *rfwd;
590 if ((c = channel_by_id(fctx->cid)) == NULL) {
591 /* no channel for reply */
592 error("%s: unknown channel", __func__);
596 if (fctx->fid >= options.num_remote_forwards) {
597 xasprintf(&failmsg, "unknown forwarding id %d", fctx->fid);
600 rfwd = &options.remote_forwards[fctx->fid];
601 debug("%s: %s for: listen %d, connect %s:%d", __func__,
602 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
603 rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
604 rfwd->connect_host, rfwd->connect_port);
605 if (type == SSH2_MSG_REQUEST_SUCCESS) {
606 if (rfwd->listen_port == 0) {
607 rfwd->allocated_port = packet_get_int();
608 logit("Allocated port %u for mux remote forward"
609 " to %s:%d", rfwd->allocated_port,
610 rfwd->connect_host, rfwd->connect_port);
611 buffer_put_int(&out, MUX_S_REMOTE_PORT);
612 buffer_put_int(&out, fctx->rid);
613 buffer_put_int(&out, rfwd->allocated_port);
614 channel_update_permitted_opens(rfwd->handle,
615 rfwd->allocated_port);
617 buffer_put_int(&out, MUX_S_OK);
618 buffer_put_int(&out, fctx->rid);
622 if (rfwd->listen_port == 0)
623 channel_update_permitted_opens(rfwd->handle, -1);
624 if (rfwd->listen_path != NULL)
625 xasprintf(&failmsg, "remote port forwarding failed for "
626 "listen path %s", rfwd->listen_path);
628 xasprintf(&failmsg, "remote port forwarding failed for "
629 "listen port %d", rfwd->listen_port);
632 error("%s: %s", __func__, failmsg);
633 buffer_put_int(&out, MUX_S_FAILURE);
634 buffer_put_int(&out, fctx->rid);
635 buffer_put_cstring(&out, failmsg);
638 buffer_put_string(&c->output, buffer_ptr(&out), buffer_len(&out));
640 if (c->mux_pause <= 0)
641 fatal("%s: mux_pause %d", __func__, c->mux_pause);
642 c->mux_pause = 0; /* start processing messages again */
646 process_mux_open_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
649 char *fwd_desc = NULL;
650 char *listen_addr, *connect_addr;
653 int i, ret = 0, freefwd = 1;
655 /* XXX - lport/cport check redundant */
656 if (buffer_get_int_ret(&ftype, m) != 0 ||
657 (listen_addr = buffer_get_string_ret(m, NULL)) == NULL ||
658 buffer_get_int_ret(&lport, m) != 0 ||
659 (connect_addr = buffer_get_string_ret(m, NULL)) == NULL ||
660 buffer_get_int_ret(&cport, m) != 0 ||
661 (lport != (u_int)PORT_STREAMLOCAL && lport > 65535) ||
662 (cport != (u_int)PORT_STREAMLOCAL && cport > 65535)) {
663 error("%s: malformed message", __func__);
667 if (*listen_addr == '\0') {
671 if (*connect_addr == '\0') {
676 memset(&fwd, 0, sizeof(fwd));
677 fwd.listen_port = lport;
678 if (fwd.listen_port == PORT_STREAMLOCAL)
679 fwd.listen_path = listen_addr;
681 fwd.listen_host = listen_addr;
682 fwd.connect_port = cport;
683 if (fwd.connect_port == PORT_STREAMLOCAL)
684 fwd.connect_path = connect_addr;
686 fwd.connect_host = connect_addr;
688 debug2("%s: channel %d: request %s", __func__, c->self,
689 (fwd_desc = format_forward(ftype, &fwd)));
691 if (ftype != MUX_FWD_LOCAL && ftype != MUX_FWD_REMOTE &&
692 ftype != MUX_FWD_DYNAMIC) {
693 logit("%s: invalid forwarding type %u", __func__, ftype);
697 buffer_put_int(r, MUX_S_FAILURE);
698 buffer_put_int(r, rid);
699 buffer_put_cstring(r, "Invalid forwarding request");
702 if (ftype == MUX_FWD_DYNAMIC && fwd.listen_path) {
703 logit("%s: streamlocal and dynamic forwards "
704 "are mutually exclusive", __func__);
707 if (fwd.listen_port != PORT_STREAMLOCAL && fwd.listen_port >= 65536) {
708 logit("%s: invalid listen port %u", __func__,
712 if ((fwd.connect_port != PORT_STREAMLOCAL && fwd.connect_port >= 65536)
713 || (ftype != MUX_FWD_DYNAMIC && ftype != MUX_FWD_REMOTE && fwd.connect_port == 0)) {
714 logit("%s: invalid connect port %u", __func__,
718 if (ftype != MUX_FWD_DYNAMIC && fwd.connect_host == NULL && fwd.connect_path == NULL) {
719 logit("%s: missing connect host", __func__);
723 /* Skip forwards that have already been requested */
726 case MUX_FWD_DYNAMIC:
727 for (i = 0; i < options.num_local_forwards; i++) {
728 if (compare_forward(&fwd,
729 options.local_forwards + i)) {
731 debug2("%s: found existing forwarding",
733 buffer_put_int(r, MUX_S_OK);
734 buffer_put_int(r, rid);
740 for (i = 0; i < options.num_remote_forwards; i++) {
741 if (compare_forward(&fwd,
742 options.remote_forwards + i)) {
743 if (fwd.listen_port != 0)
745 debug2("%s: found allocated port",
747 buffer_put_int(r, MUX_S_REMOTE_PORT);
748 buffer_put_int(r, rid);
750 options.remote_forwards[i].allocated_port);
757 if (options.control_master == SSHCTL_MASTER_ASK ||
758 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
759 if (!ask_permission("Open %s on %s?", fwd_desc, host)) {
760 debug2("%s: forwarding refused by user", __func__);
761 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
762 buffer_put_int(r, rid);
763 buffer_put_cstring(r, "Permission denied");
768 if (ftype == MUX_FWD_LOCAL || ftype == MUX_FWD_DYNAMIC) {
769 if (!channel_setup_local_fwd_listener(&fwd,
770 &options.fwd_opts)) {
772 logit("slave-requested %s failed", fwd_desc);
773 buffer_put_int(r, MUX_S_FAILURE);
774 buffer_put_int(r, rid);
775 buffer_put_cstring(r, "Port forwarding failed");
778 add_local_forward(&options, &fwd);
781 struct mux_channel_confirm_ctx *fctx;
783 fwd.handle = channel_request_remote_forwarding(&fwd);
786 add_remote_forward(&options, &fwd);
787 fctx = xcalloc(1, sizeof(*fctx));
790 fctx->fid = options.num_remote_forwards - 1;
791 client_register_global_confirm(mux_confirm_remote_forward,
794 c->mux_pause = 1; /* wait for mux_confirm_remote_forward */
795 /* delayed reply in mux_confirm_remote_forward */
798 buffer_put_int(r, MUX_S_OK);
799 buffer_put_int(r, rid);
803 free(fwd.listen_host);
804 free(fwd.listen_path);
805 free(fwd.connect_host);
806 free(fwd.connect_path);
812 process_mux_close_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
814 struct Forward fwd, *found_fwd;
815 char *fwd_desc = NULL;
816 const char *error_reason = NULL;
817 char *listen_addr = NULL, *connect_addr = NULL;
822 if (buffer_get_int_ret(&ftype, m) != 0 ||
823 (listen_addr = buffer_get_string_ret(m, NULL)) == NULL ||
824 buffer_get_int_ret(&lport, m) != 0 ||
825 (connect_addr = buffer_get_string_ret(m, NULL)) == NULL ||
826 buffer_get_int_ret(&cport, m) != 0 ||
827 (lport != (u_int)PORT_STREAMLOCAL && lport > 65535) ||
828 (cport != (u_int)PORT_STREAMLOCAL && cport > 65535)) {
829 error("%s: malformed message", __func__);
834 if (*listen_addr == '\0') {
838 if (*connect_addr == '\0') {
843 memset(&fwd, 0, sizeof(fwd));
844 fwd.listen_port = lport;
845 if (fwd.listen_port == PORT_STREAMLOCAL)
846 fwd.listen_path = listen_addr;
848 fwd.listen_host = listen_addr;
849 fwd.connect_port = cport;
850 if (fwd.connect_port == PORT_STREAMLOCAL)
851 fwd.connect_path = connect_addr;
853 fwd.connect_host = connect_addr;
855 debug2("%s: channel %d: request cancel %s", __func__, c->self,
856 (fwd_desc = format_forward(ftype, &fwd)));
858 /* make sure this has been requested */
862 case MUX_FWD_DYNAMIC:
863 for (i = 0; i < options.num_local_forwards; i++) {
864 if (compare_forward(&fwd,
865 options.local_forwards + i)) {
866 found_fwd = options.local_forwards + i;
872 for (i = 0; i < options.num_remote_forwards; i++) {
873 if (compare_forward(&fwd,
874 options.remote_forwards + i)) {
875 found_fwd = options.remote_forwards + i;
882 if (found_fwd == NULL)
883 error_reason = "port not forwarded";
884 else if (ftype == MUX_FWD_REMOTE) {
886 * This shouldn't fail unless we confused the host/port
887 * between options.remote_forwards and permitted_opens.
888 * However, for dynamic allocated listen ports we need
889 * to use the actual listen port.
891 if (channel_request_rforward_cancel(found_fwd) == -1)
892 error_reason = "port not in permitted opens";
893 } else { /* local and dynamic forwards */
895 if (channel_cancel_lport_listener(&fwd, fwd.connect_port,
896 &options.fwd_opts) == -1)
897 error_reason = "port not found";
900 if (error_reason == NULL) {
901 buffer_put_int(r, MUX_S_OK);
902 buffer_put_int(r, rid);
904 free(found_fwd->listen_host);
905 free(found_fwd->listen_path);
906 free(found_fwd->connect_host);
907 free(found_fwd->connect_path);
908 found_fwd->listen_host = found_fwd->connect_host = NULL;
909 found_fwd->listen_path = found_fwd->connect_path = NULL;
910 found_fwd->listen_port = found_fwd->connect_port = 0;
912 buffer_put_int(r, MUX_S_FAILURE);
913 buffer_put_int(r, rid);
914 buffer_put_cstring(r, error_reason);
925 process_mux_stdio_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
928 char *reserved, *chost;
931 struct mux_stdio_confirm_ctx *cctx;
933 chost = reserved = NULL;
934 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
935 (chost = buffer_get_string_ret(m, NULL)) == NULL ||
936 buffer_get_int_ret(&cport, m) != 0) {
939 error("%s: malformed message", __func__);
944 debug2("%s: channel %d: request stdio fwd to %s:%u",
945 __func__, c->self, chost, cport);
947 /* Gather fds from client */
948 for(i = 0; i < 2; i++) {
949 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
950 error("%s: failed to receive fd %d from slave",
952 for (j = 0; j < i; j++)
957 buffer_put_int(r, MUX_S_FAILURE);
958 buffer_put_int(r, rid);
959 buffer_put_cstring(r,
960 "did not receive file descriptors");
965 debug3("%s: got fds stdin %d, stdout %d", __func__,
966 new_fd[0], new_fd[1]);
968 /* XXX support multiple child sessions in future */
969 if (c->remote_id != -1) {
970 debug2("%s: session already open", __func__);
972 buffer_put_int(r, MUX_S_FAILURE);
973 buffer_put_int(r, rid);
974 buffer_put_cstring(r, "Multiple sessions not supported");
982 if (options.control_master == SSHCTL_MASTER_ASK ||
983 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
984 if (!ask_permission("Allow forward to %s:%u? ",
986 debug2("%s: stdio fwd refused by user", __func__);
988 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
989 buffer_put_int(r, rid);
990 buffer_put_cstring(r, "Permission denied");
995 /* enable nonblocking unless tty */
996 if (!isatty(new_fd[0]))
997 set_nonblock(new_fd[0]);
998 if (!isatty(new_fd[1]))
999 set_nonblock(new_fd[1]);
1001 nc = channel_connect_stdio_fwd(chost, cport, new_fd[0], new_fd[1]);
1003 nc->ctl_chan = c->self; /* link session -> control channel */
1004 c->remote_id = nc->self; /* link control -> session channel */
1006 debug2("%s: channel_new: %d linked to control channel %d",
1007 __func__, nc->self, nc->ctl_chan);
1009 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
1011 cctx = xcalloc(1, sizeof(*cctx));
1013 channel_register_open_confirm(nc->self, mux_stdio_confirm, cctx);
1014 c->mux_pause = 1; /* stop handling messages until open_confirm done */
1016 /* reply is deferred, sent by mux_session_confirm */
1020 /* Callback on open confirmation in mux master for a mux stdio fwd session. */
1022 mux_stdio_confirm(int id, int success, void *arg)
1024 struct mux_stdio_confirm_ctx *cctx = arg;
1029 fatal("%s: cctx == NULL", __func__);
1030 if ((c = channel_by_id(id)) == NULL)
1031 fatal("%s: no channel for id %d", __func__, id);
1032 if ((cc = channel_by_id(c->ctl_chan)) == NULL)
1033 fatal("%s: channel %d lacks control channel %d", __func__,
1037 debug3("%s: sending failure reply", __func__);
1039 buffer_init(&reply);
1040 buffer_put_int(&reply, MUX_S_FAILURE);
1041 buffer_put_int(&reply, cctx->rid);
1042 buffer_put_cstring(&reply, "Session open refused by peer");
1046 debug3("%s: sending success reply", __func__);
1048 buffer_init(&reply);
1049 buffer_put_int(&reply, MUX_S_SESSION_OPENED);
1050 buffer_put_int(&reply, cctx->rid);
1051 buffer_put_int(&reply, c->self);
1055 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
1056 buffer_free(&reply);
1058 if (cc->mux_pause <= 0)
1059 fatal("%s: mux_pause %d", __func__, cc->mux_pause);
1060 cc->mux_pause = 0; /* start processing messages again */
1061 c->open_confirm_ctx = NULL;
1066 process_mux_stop_listening(u_int rid, Channel *c, Buffer *m, Buffer *r)
1068 debug("%s: channel %d: stop listening", __func__, c->self);
1070 if (options.control_master == SSHCTL_MASTER_ASK ||
1071 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
1072 if (!ask_permission("Disable further multiplexing on shared "
1073 "connection to %s? ", host)) {
1074 debug2("%s: stop listen refused by user", __func__);
1075 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
1076 buffer_put_int(r, rid);
1077 buffer_put_cstring(r, "Permission denied");
1082 if (mux_listener_channel != NULL) {
1083 channel_free(mux_listener_channel);
1085 free(options.control_path);
1086 options.control_path = NULL;
1087 mux_listener_channel = NULL;
1088 muxserver_sock = -1;
1092 buffer_put_int(r, MUX_S_OK);
1093 buffer_put_int(r, rid);
1098 /* Channel callbacks fired on read/write from mux slave fd */
1100 mux_master_read_cb(Channel *c)
1102 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
1105 u_int type, rid, have, i;
1109 if (c->mux_ctx == NULL) {
1110 state = xcalloc(1, sizeof(*state));
1112 channel_register_cleanup(c->self,
1113 mux_master_control_cleanup_cb, 0);
1117 buffer_put_int(&out, MUX_MSG_HELLO);
1118 buffer_put_int(&out, SSHMUX_VER);
1120 buffer_put_string(&c->output, buffer_ptr(&out),
1123 debug3("%s: channel %d: hello sent", __func__, c->self);
1130 /* Channel code ensures that we receive whole packets */
1131 if ((ptr = buffer_get_string_ptr_ret(&c->input, &have)) == NULL) {
1133 error("%s: malformed message", __func__);
1136 buffer_append(&in, ptr, have);
1138 if (buffer_get_int_ret(&type, &in) != 0)
1140 debug3("%s: channel %d packet type 0x%08x len %u",
1141 __func__, c->self, type, buffer_len(&in));
1143 if (type == MUX_MSG_HELLO)
1146 if (!state->hello_rcvd) {
1147 error("%s: expected MUX_MSG_HELLO(0x%08x), "
1148 "received 0x%08x", __func__, MUX_MSG_HELLO, type);
1151 if (buffer_get_int_ret(&rid, &in) != 0)
1155 for (i = 0; mux_master_handlers[i].handler != NULL; i++) {
1156 if (type == mux_master_handlers[i].type) {
1157 ret = mux_master_handlers[i].handler(rid, c, &in, &out);
1161 if (mux_master_handlers[i].handler == NULL) {
1162 error("%s: unsupported mux message 0x%08x", __func__, type);
1163 buffer_put_int(&out, MUX_S_FAILURE);
1164 buffer_put_int(&out, rid);
1165 buffer_put_cstring(&out, "unsupported request");
1168 /* Enqueue reply packet */
1169 if (buffer_len(&out) != 0) {
1170 buffer_put_string(&c->output, buffer_ptr(&out),
1180 mux_exit_message(Channel *c, int exitval)
1185 debug3("%s: channel %d: exit message, exitval %d", __func__, c->self,
1188 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL)
1189 fatal("%s: channel %d missing mux channel %d",
1190 __func__, c->self, c->ctl_chan);
1192 /* Append exit message packet to control socket output queue */
1194 buffer_put_int(&m, MUX_S_EXIT_MESSAGE);
1195 buffer_put_int(&m, c->self);
1196 buffer_put_int(&m, exitval);
1198 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1203 mux_tty_alloc_failed(Channel *c)
1208 debug3("%s: channel %d: TTY alloc failed", __func__, c->self);
1210 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL)
1211 fatal("%s: channel %d missing mux channel %d",
1212 __func__, c->self, c->ctl_chan);
1214 /* Append exit message packet to control socket output queue */
1216 buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL);
1217 buffer_put_int(&m, c->self);
1219 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1223 /* Prepare a mux master to listen on a Unix domain socket. */
1225 muxserver_listen(void)
1228 char *orig_control_path = options.control_path;
1233 if (options.control_path == NULL ||
1234 options.control_master == SSHCTL_MASTER_NO)
1237 debug("setting up multiplex master socket");
1240 * Use a temporary path before listen so we can pseudo-atomically
1241 * establish the listening socket in its final location to avoid
1242 * other processes racing in between bind() and listen() and hitting
1243 * an unready socket.
1245 for (i = 0; i < sizeof(rbuf) - 1; i++) {
1246 r = arc4random_uniform(26+26+10);
1247 rbuf[i] = (r < 26) ? 'a' + r :
1248 (r < 26*2) ? 'A' + r - 26 :
1251 rbuf[sizeof(rbuf) - 1] = '\0';
1252 options.control_path = NULL;
1253 xasprintf(&options.control_path, "%s.%s", orig_control_path, rbuf);
1254 debug3("%s: temporary control path %s", __func__, options.control_path);
1256 old_umask = umask(0177);
1257 muxserver_sock = unix_listener(options.control_path, 64, 0);
1260 if (muxserver_sock < 0) {
1261 if (oerrno == EINVAL || oerrno == EADDRINUSE) {
1262 error("ControlSocket %s already exists, "
1263 "disabling multiplexing", options.control_path);
1265 if (muxserver_sock != -1) {
1266 close(muxserver_sock);
1267 muxserver_sock = -1;
1269 free(orig_control_path);
1270 free(options.control_path);
1271 options.control_path = NULL;
1272 options.control_master = SSHCTL_MASTER_NO;
1275 /* unix_listener() logs the error */
1280 /* Now atomically "move" the mux socket into position */
1281 if (link(options.control_path, orig_control_path) != 0) {
1282 if (errno != EEXIST) {
1283 fatal("%s: link mux listener %s => %s: %s", __func__,
1284 options.control_path, orig_control_path,
1287 error("ControlSocket %s already exists, disabling multiplexing",
1289 unlink(options.control_path);
1290 goto disable_mux_master;
1292 unlink(options.control_path);
1293 free(options.control_path);
1294 options.control_path = orig_control_path;
1296 set_nonblock(muxserver_sock);
1298 mux_listener_channel = channel_new("mux listener",
1299 SSH_CHANNEL_MUX_LISTENER, muxserver_sock, muxserver_sock, -1,
1300 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1301 0, options.control_path, 1);
1302 mux_listener_channel->mux_rcb = mux_master_read_cb;
1303 debug3("%s: mux listener channel %d fd %d", __func__,
1304 mux_listener_channel->self, mux_listener_channel->sock);
1307 /* Callback on open confirmation in mux master for a mux client session. */
1309 mux_session_confirm(int id, int success, void *arg)
1311 struct mux_session_confirm_ctx *cctx = arg;
1312 const char *display;
1318 fatal("%s: cctx == NULL", __func__);
1319 if ((c = channel_by_id(id)) == NULL)
1320 fatal("%s: no channel for id %d", __func__, id);
1321 if ((cc = channel_by_id(c->ctl_chan)) == NULL)
1322 fatal("%s: channel %d lacks control channel %d", __func__,
1326 debug3("%s: sending failure reply", __func__);
1328 buffer_init(&reply);
1329 buffer_put_int(&reply, MUX_S_FAILURE);
1330 buffer_put_int(&reply, cctx->rid);
1331 buffer_put_cstring(&reply, "Session open refused by peer");
1335 display = getenv("DISPLAY");
1336 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
1339 /* Get reasonable local authentication information. */
1340 client_x11_get_proto(display, options.xauth_location,
1341 options.forward_x11_trusted, options.forward_x11_timeout,
1343 /* Request forwarding with authentication spoofing. */
1344 debug("Requesting X11 forwarding with authentication "
1346 x11_request_forwarding_with_spoofing(id, display, proto,
1348 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1349 /* XXX exit_on_forward_failure */
1352 if (cctx->want_agent_fwd && options.forward_agent) {
1353 debug("Requesting authentication agent forwarding.");
1354 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1358 client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
1359 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env);
1361 debug3("%s: sending success reply", __func__);
1363 buffer_init(&reply);
1364 buffer_put_int(&reply, MUX_S_SESSION_OPENED);
1365 buffer_put_int(&reply, cctx->rid);
1366 buffer_put_int(&reply, c->self);
1370 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
1371 buffer_free(&reply);
1373 if (cc->mux_pause <= 0)
1374 fatal("%s: mux_pause %d", __func__, cc->mux_pause);
1375 cc->mux_pause = 0; /* start processing messages again */
1376 c->open_confirm_ctx = NULL;
1377 buffer_free(&cctx->cmd);
1379 if (cctx->env != NULL) {
1380 for (i = 0; cctx->env[i] != NULL; i++)
1387 /* ** Multiplexing client support */
1389 /* Exit signal handler */
1391 control_client_sighandler(int signo)
1393 muxclient_terminate = signo;
1397 * Relay signal handler - used to pass some signals from mux client to
1401 control_client_sigrelay(int signo)
1403 int save_errno = errno;
1405 if (muxserver_pid > 1)
1406 kill(muxserver_pid, signo);
1412 mux_client_read(int fd, Buffer *b, u_int need)
1420 pfd.events = POLLIN;
1421 p = buffer_append_space(b, need);
1422 for (have = 0; have < need; ) {
1423 if (muxclient_terminate) {
1427 len = read(fd, p + have, need - have);
1430 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1434 (void)poll(&pfd, 1, -1);
1452 mux_client_write_packet(int fd, Buffer *m)
1461 pfd.events = POLLOUT;
1462 buffer_init(&queue);
1463 buffer_put_string(&queue, buffer_ptr(m), buffer_len(m));
1465 need = buffer_len(&queue);
1466 ptr = buffer_ptr(&queue);
1468 for (have = 0; have < need; ) {
1469 if (muxclient_terminate) {
1470 buffer_free(&queue);
1474 len = write(fd, ptr + have, need - have);
1477 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1481 (void)poll(&pfd, 1, -1);
1487 buffer_free(&queue);
1493 buffer_free(&queue);
1499 buffer_free(&queue);
1504 mux_client_read_packet(int fd, Buffer *m)
1511 buffer_init(&queue);
1512 if (mux_client_read(fd, &queue, 4) != 0) {
1513 if ((oerrno = errno) == EPIPE)
1514 debug3("%s: read header failed: %s", __func__,
1516 buffer_free(&queue);
1520 need = get_u32(buffer_ptr(&queue));
1521 if (mux_client_read(fd, &queue, need) != 0) {
1523 debug3("%s: read body failed: %s", __func__, strerror(errno));
1524 buffer_free(&queue);
1528 ptr = buffer_get_string_ptr(&queue, &have);
1529 buffer_append(m, ptr, have);
1530 buffer_free(&queue);
1535 mux_client_hello_exchange(int fd)
1541 buffer_put_int(&m, MUX_MSG_HELLO);
1542 buffer_put_int(&m, SSHMUX_VER);
1545 if (mux_client_write_packet(fd, &m) != 0)
1546 fatal("%s: write packet: %s", __func__, strerror(errno));
1550 /* Read their HELLO */
1551 if (mux_client_read_packet(fd, &m) != 0) {
1556 type = buffer_get_int(&m);
1557 if (type != MUX_MSG_HELLO)
1558 fatal("%s: expected HELLO (%u) received %u",
1559 __func__, MUX_MSG_HELLO, type);
1560 ver = buffer_get_int(&m);
1561 if (ver != SSHMUX_VER)
1562 fatal("Unsupported multiplexing protocol version %d "
1563 "(expected %d)", ver, SSHMUX_VER);
1564 debug2("%s: master version %u", __func__, ver);
1565 /* No extensions are presently defined */
1566 while (buffer_len(&m) > 0) {
1567 char *name = buffer_get_string(&m, NULL);
1568 char *value = buffer_get_string(&m, NULL);
1570 debug2("Unrecognised master extension \"%s\"", name);
1579 mux_client_request_alive(int fd)
1583 u_int pid, type, rid;
1585 debug3("%s: entering", __func__);
1588 buffer_put_int(&m, MUX_C_ALIVE_CHECK);
1589 buffer_put_int(&m, muxclient_request_id);
1591 if (mux_client_write_packet(fd, &m) != 0)
1592 fatal("%s: write packet: %s", __func__, strerror(errno));
1596 /* Read their reply */
1597 if (mux_client_read_packet(fd, &m) != 0) {
1602 type = buffer_get_int(&m);
1603 if (type != MUX_S_ALIVE) {
1604 e = buffer_get_string(&m, NULL);
1605 fatal("%s: master returned error: %s", __func__, e);
1608 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1609 fatal("%s: out of sequence reply: my id %u theirs %u",
1610 __func__, muxclient_request_id, rid);
1611 pid = buffer_get_int(&m);
1614 debug3("%s: done pid = %u", __func__, pid);
1616 muxclient_request_id++;
1622 mux_client_request_terminate(int fd)
1628 debug3("%s: entering", __func__);
1631 buffer_put_int(&m, MUX_C_TERMINATE);
1632 buffer_put_int(&m, muxclient_request_id);
1634 if (mux_client_write_packet(fd, &m) != 0)
1635 fatal("%s: write packet: %s", __func__, strerror(errno));
1639 /* Read their reply */
1640 if (mux_client_read_packet(fd, &m) != 0) {
1641 /* Remote end exited already */
1642 if (errno == EPIPE) {
1646 fatal("%s: read from master failed: %s",
1647 __func__, strerror(errno));
1650 type = buffer_get_int(&m);
1651 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1652 fatal("%s: out of sequence reply: my id %u theirs %u",
1653 __func__, muxclient_request_id, rid);
1657 case MUX_S_PERMISSION_DENIED:
1658 e = buffer_get_string(&m, NULL);
1659 fatal("Master refused termination request: %s", e);
1661 e = buffer_get_string(&m, NULL);
1662 fatal("%s: termination request failed: %s", __func__, e);
1664 fatal("%s: unexpected response from master 0x%08x",
1668 muxclient_request_id++;
1672 mux_client_forward(int fd, int cancel_flag, u_int ftype, struct Forward *fwd)
1678 fwd_desc = format_forward(ftype, fwd);
1679 debug("Requesting %s %s",
1680 cancel_flag ? "cancellation of" : "forwarding of", fwd_desc);
1684 buffer_put_int(&m, cancel_flag ? MUX_C_CLOSE_FWD : MUX_C_OPEN_FWD);
1685 buffer_put_int(&m, muxclient_request_id);
1686 buffer_put_int(&m, ftype);
1687 if (fwd->listen_path != NULL) {
1688 buffer_put_cstring(&m, fwd->listen_path);
1690 buffer_put_cstring(&m,
1691 fwd->listen_host == NULL ? "" :
1692 (*fwd->listen_host == '\0' ? "*" : fwd->listen_host));
1694 buffer_put_int(&m, fwd->listen_port);
1695 if (fwd->connect_path != NULL) {
1696 buffer_put_cstring(&m, fwd->connect_path);
1698 buffer_put_cstring(&m,
1699 fwd->connect_host == NULL ? "" : fwd->connect_host);
1701 buffer_put_int(&m, fwd->connect_port);
1703 if (mux_client_write_packet(fd, &m) != 0)
1704 fatal("%s: write packet: %s", __func__, strerror(errno));
1708 /* Read their reply */
1709 if (mux_client_read_packet(fd, &m) != 0) {
1714 type = buffer_get_int(&m);
1715 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1716 fatal("%s: out of sequence reply: my id %u theirs %u",
1717 __func__, muxclient_request_id, rid);
1721 case MUX_S_REMOTE_PORT:
1723 fatal("%s: got MUX_S_REMOTE_PORT for cancel", __func__);
1724 fwd->allocated_port = buffer_get_int(&m);
1725 logit("Allocated port %u for remote forward to %s:%d",
1726 fwd->allocated_port,
1727 fwd->connect_host ? fwd->connect_host : "",
1729 if (muxclient_command == SSHMUX_COMMAND_FORWARD)
1730 fprintf(stdout, "%u\n", fwd->allocated_port);
1732 case MUX_S_PERMISSION_DENIED:
1733 e = buffer_get_string(&m, NULL);
1735 error("Master refused forwarding request: %s", e);
1738 e = buffer_get_string(&m, NULL);
1740 error("%s: forwarding request failed: %s", __func__, e);
1743 fatal("%s: unexpected response from master 0x%08x",
1748 muxclient_request_id++;
1753 mux_client_forwards(int fd, int cancel_flag)
1757 debug3("%s: %s forwardings: %d local, %d remote", __func__,
1758 cancel_flag ? "cancel" : "request",
1759 options.num_local_forwards, options.num_remote_forwards);
1761 /* XXX ExitOnForwardingFailure */
1762 for (i = 0; i < options.num_local_forwards; i++) {
1763 if (mux_client_forward(fd, cancel_flag,
1764 options.local_forwards[i].connect_port == 0 ?
1765 MUX_FWD_DYNAMIC : MUX_FWD_LOCAL,
1766 options.local_forwards + i) != 0)
1769 for (i = 0; i < options.num_remote_forwards; i++) {
1770 if (mux_client_forward(fd, cancel_flag, MUX_FWD_REMOTE,
1771 options.remote_forwards + i) != 0)
1778 mux_client_request_session(int fd)
1782 u_int i, rid, sid, esid, exitval, type, exitval_seen;
1783 extern char **environ;
1784 int devnull, rawmode;
1786 debug3("%s: entering", __func__);
1788 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
1789 error("%s: master alive request failed", __func__);
1793 signal(SIGPIPE, SIG_IGN);
1795 if (stdin_null_flag) {
1796 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1797 fatal("open(/dev/null): %s", strerror(errno));
1798 if (dup2(devnull, STDIN_FILENO) == -1)
1799 fatal("dup2: %s", strerror(errno));
1800 if (devnull > STDERR_FILENO)
1804 term = getenv("TERM");
1807 buffer_put_int(&m, MUX_C_NEW_SESSION);
1808 buffer_put_int(&m, muxclient_request_id);
1809 buffer_put_cstring(&m, ""); /* reserved */
1810 buffer_put_int(&m, tty_flag);
1811 buffer_put_int(&m, options.forward_x11);
1812 buffer_put_int(&m, options.forward_agent);
1813 buffer_put_int(&m, subsystem_flag);
1814 buffer_put_int(&m, options.escape_char == SSH_ESCAPECHAR_NONE ?
1815 0xffffffff : (u_int)options.escape_char);
1816 buffer_put_cstring(&m, term == NULL ? "" : term);
1817 buffer_put_string(&m, buffer_ptr(&command), buffer_len(&command));
1819 if (options.num_send_env > 0 && environ != NULL) {
1820 /* Pass environment */
1821 for (i = 0; environ[i] != NULL; i++) {
1822 if (env_permitted(environ[i])) {
1823 buffer_put_cstring(&m, environ[i]);
1828 if (mux_client_write_packet(fd, &m) != 0)
1829 fatal("%s: write packet: %s", __func__, strerror(errno));
1831 /* Send the stdio file descriptors */
1832 if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
1833 mm_send_fd(fd, STDOUT_FILENO) == -1 ||
1834 mm_send_fd(fd, STDERR_FILENO) == -1)
1835 fatal("%s: send fds failed", __func__);
1837 debug3("%s: session request sent", __func__);
1839 /* Read their reply */
1841 if (mux_client_read_packet(fd, &m) != 0) {
1842 error("%s: read from master failed: %s",
1843 __func__, strerror(errno));
1848 type = buffer_get_int(&m);
1849 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1850 fatal("%s: out of sequence reply: my id %u theirs %u",
1851 __func__, muxclient_request_id, rid);
1853 case MUX_S_SESSION_OPENED:
1854 sid = buffer_get_int(&m);
1855 debug("%s: master session id: %u", __func__, sid);
1857 case MUX_S_PERMISSION_DENIED:
1858 e = buffer_get_string(&m, NULL);
1860 error("Master refused session request: %s", e);
1863 e = buffer_get_string(&m, NULL);
1865 error("%s: session request failed: %s", __func__, e);
1869 error("%s: unexpected response from master 0x%08x",
1873 muxclient_request_id++;
1875 signal(SIGHUP, control_client_sighandler);
1876 signal(SIGINT, control_client_sighandler);
1877 signal(SIGTERM, control_client_sighandler);
1878 signal(SIGWINCH, control_client_sigrelay);
1882 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1885 * Stick around until the controlee closes the client_fd.
1886 * Before it does, it is expected to write an exit message.
1887 * This process must read the value and wait for the closure of
1888 * the client_fd; if this one closes early, the multiplex master will
1889 * terminate early too (possibly losing data).
1891 for (exitval = 255, exitval_seen = 0;;) {
1893 if (mux_client_read_packet(fd, &m) != 0)
1895 type = buffer_get_int(&m);
1897 case MUX_S_TTY_ALLOC_FAIL:
1898 if ((esid = buffer_get_int(&m)) != sid)
1899 fatal("%s: tty alloc fail on unknown session: "
1900 "my id %u theirs %u",
1901 __func__, sid, esid);
1902 leave_raw_mode(options.request_tty ==
1906 case MUX_S_EXIT_MESSAGE:
1907 if ((esid = buffer_get_int(&m)) != sid)
1908 fatal("%s: exit on unknown session: "
1909 "my id %u theirs %u",
1910 __func__, sid, esid);
1912 fatal("%s: exitval sent twice", __func__);
1913 exitval = buffer_get_int(&m);
1917 e = buffer_get_string(&m, NULL);
1918 fatal("%s: master returned error: %s", __func__, e);
1924 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1926 if (muxclient_terminate) {
1927 debug2("Exiting on signal %d", muxclient_terminate);
1929 } else if (!exitval_seen) {
1930 debug2("Control master terminated unexpectedly");
1933 debug2("Received exit status from master %d", exitval);
1935 if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1936 fprintf(stderr, "Shared connection to %s closed.\r\n", host);
1942 mux_client_request_stdio_fwd(int fd)
1946 u_int type, rid, sid;
1949 debug3("%s: entering", __func__);
1951 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
1952 error("%s: master alive request failed", __func__);
1956 signal(SIGPIPE, SIG_IGN);
1958 if (stdin_null_flag) {
1959 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1960 fatal("open(/dev/null): %s", strerror(errno));
1961 if (dup2(devnull, STDIN_FILENO) == -1)
1962 fatal("dup2: %s", strerror(errno));
1963 if (devnull > STDERR_FILENO)
1968 buffer_put_int(&m, MUX_C_NEW_STDIO_FWD);
1969 buffer_put_int(&m, muxclient_request_id);
1970 buffer_put_cstring(&m, ""); /* reserved */
1971 buffer_put_cstring(&m, stdio_forward_host);
1972 buffer_put_int(&m, stdio_forward_port);
1974 if (mux_client_write_packet(fd, &m) != 0)
1975 fatal("%s: write packet: %s", __func__, strerror(errno));
1977 /* Send the stdio file descriptors */
1978 if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
1979 mm_send_fd(fd, STDOUT_FILENO) == -1)
1980 fatal("%s: send fds failed", __func__);
1982 debug3("%s: stdio forward request sent", __func__);
1984 /* Read their reply */
1987 if (mux_client_read_packet(fd, &m) != 0) {
1988 error("%s: read from master failed: %s",
1989 __func__, strerror(errno));
1994 type = buffer_get_int(&m);
1995 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1996 fatal("%s: out of sequence reply: my id %u theirs %u",
1997 __func__, muxclient_request_id, rid);
1999 case MUX_S_SESSION_OPENED:
2000 sid = buffer_get_int(&m);
2001 debug("%s: master session id: %u", __func__, sid);
2003 case MUX_S_PERMISSION_DENIED:
2004 e = buffer_get_string(&m, NULL);
2006 fatal("Master refused stdio forwarding request: %s", e);
2008 e = buffer_get_string(&m, NULL);
2010 fatal("Stdio forwarding request failed: %s", e);
2013 error("%s: unexpected response from master 0x%08x",
2017 muxclient_request_id++;
2019 signal(SIGHUP, control_client_sighandler);
2020 signal(SIGINT, control_client_sighandler);
2021 signal(SIGTERM, control_client_sighandler);
2022 signal(SIGWINCH, control_client_sigrelay);
2025 * Stick around until the controlee closes the client_fd.
2028 if (mux_client_read_packet(fd, &m) != 0) {
2029 if (errno == EPIPE ||
2030 (errno == EINTR && muxclient_terminate != 0))
2032 fatal("%s: mux_client_read_packet: %s",
2033 __func__, strerror(errno));
2035 fatal("%s: master returned unexpected message %u", __func__, type);
2039 mux_client_request_stop_listening(int fd)
2045 debug3("%s: entering", __func__);
2048 buffer_put_int(&m, MUX_C_STOP_LISTENING);
2049 buffer_put_int(&m, muxclient_request_id);
2051 if (mux_client_write_packet(fd, &m) != 0)
2052 fatal("%s: write packet: %s", __func__, strerror(errno));
2056 /* Read their reply */
2057 if (mux_client_read_packet(fd, &m) != 0)
2058 fatal("%s: read from master failed: %s",
2059 __func__, strerror(errno));
2061 type = buffer_get_int(&m);
2062 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
2063 fatal("%s: out of sequence reply: my id %u theirs %u",
2064 __func__, muxclient_request_id, rid);
2068 case MUX_S_PERMISSION_DENIED:
2069 e = buffer_get_string(&m, NULL);
2070 fatal("Master refused stop listening request: %s", e);
2072 e = buffer_get_string(&m, NULL);
2073 fatal("%s: stop listening request failed: %s", __func__, e);
2075 fatal("%s: unexpected response from master 0x%08x",
2079 muxclient_request_id++;
2082 /* Multiplex client main loop. */
2084 muxclient(const char *path)
2086 struct sockaddr_un addr;
2091 if (muxclient_command == 0) {
2092 if (stdio_forward_host != NULL)
2093 muxclient_command = SSHMUX_COMMAND_STDIO_FWD;
2095 muxclient_command = SSHMUX_COMMAND_OPEN;
2098 switch (options.control_master) {
2099 case SSHCTL_MASTER_AUTO:
2100 case SSHCTL_MASTER_AUTO_ASK:
2101 debug("auto-mux: Trying existing master");
2103 case SSHCTL_MASTER_NO:
2109 memset(&addr, '\0', sizeof(addr));
2110 addr.sun_family = AF_UNIX;
2111 sun_len = offsetof(struct sockaddr_un, sun_path) +
2114 if (strlcpy(addr.sun_path, path,
2115 sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
2116 fatal("ControlPath too long");
2118 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
2119 fatal("%s socket(): %s", __func__, strerror(errno));
2121 if (connect(sock, (struct sockaddr *)&addr, sun_len) == -1) {
2122 switch (muxclient_command) {
2123 case SSHMUX_COMMAND_OPEN:
2124 case SSHMUX_COMMAND_STDIO_FWD:
2127 fatal("Control socket connect(%.100s): %s", path,
2130 if (errno == ECONNREFUSED &&
2131 options.control_master != SSHCTL_MASTER_NO) {
2132 debug("Stale control socket %.100s, unlinking", path);
2134 } else if (errno == ENOENT) {
2135 debug("Control socket \"%.100s\" does not exist", path);
2137 error("Control socket connect(%.100s): %s", path,
2145 if (mux_client_hello_exchange(sock) != 0) {
2146 error("%s: master hello exchange failed", __func__);
2151 switch (muxclient_command) {
2152 case SSHMUX_COMMAND_ALIVE_CHECK:
2153 if ((pid = mux_client_request_alive(sock)) == 0)
2154 fatal("%s: master alive check failed", __func__);
2155 fprintf(stderr, "Master running (pid=%d)\r\n", pid);
2157 case SSHMUX_COMMAND_TERMINATE:
2158 mux_client_request_terminate(sock);
2159 fprintf(stderr, "Exit request sent.\r\n");
2161 case SSHMUX_COMMAND_FORWARD:
2162 if (mux_client_forwards(sock, 0) != 0)
2163 fatal("%s: master forward request failed", __func__);
2165 case SSHMUX_COMMAND_OPEN:
2166 if (mux_client_forwards(sock, 0) != 0) {
2167 error("%s: master forward request failed", __func__);
2170 mux_client_request_session(sock);
2172 case SSHMUX_COMMAND_STDIO_FWD:
2173 mux_client_request_stdio_fwd(sock);
2175 case SSHMUX_COMMAND_STOP:
2176 mux_client_request_stop_listening(sock);
2177 fprintf(stderr, "Stop listening request sent.\r\n");
2179 case SSHMUX_COMMAND_CANCEL_FWD:
2180 if (mux_client_forwards(sock, 1) != 0)
2181 error("%s: master cancel forward request failed",
2185 fatal("unrecognised muxclient_command %d", muxclient_command);