1 /* $OpenBSD: mux.c,v 1.58 2016/01/13 23:04:47 djm 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
36 #include <sys/types.h>
38 #include <sys/socket.h>
57 # ifdef HAVE_SYS_POLL_H
58 # include <sys/poll.h>
66 #include "openbsd-compat/sys-queue.h"
71 #include "pathnames.h"
78 #include "monitor_fdpass.h"
82 #include "clientloop.h"
86 extern Options options;
87 extern int stdin_null_flag;
89 extern int subsystem_flag;
90 extern Buffer command;
91 extern volatile sig_atomic_t quit_pending;
92 extern char *stdio_forward_host;
93 extern int stdio_forward_port;
95 /* Context for session open confirmation callback */
96 struct mux_session_confirm_ctx {
100 u_int want_agent_fwd;
108 /* Context for stdio fwd open confirmation callback */
109 struct mux_stdio_confirm_ctx {
113 /* Context for global channel callback */
114 struct mux_channel_confirm_ctx {
115 u_int cid; /* channel id */
116 u_int rid; /* request id */
117 int fid; /* forward id */
120 /* fd to control socket */
121 int muxserver_sock = -1;
123 /* client request id */
124 u_int muxclient_request_id = 0;
126 /* Multiplexing control command */
127 u_int muxclient_command = 0;
129 /* Set when signalled. */
130 static volatile sig_atomic_t muxclient_terminate = 0;
132 /* PID of multiplex server */
133 static u_int muxserver_pid = 0;
135 static Channel *mux_listener_channel = NULL;
137 struct mux_master_state {
141 /* mux protocol messages */
142 #define MUX_MSG_HELLO 0x00000001
143 #define MUX_C_NEW_SESSION 0x10000002
144 #define MUX_C_ALIVE_CHECK 0x10000004
145 #define MUX_C_TERMINATE 0x10000005
146 #define MUX_C_OPEN_FWD 0x10000006
147 #define MUX_C_CLOSE_FWD 0x10000007
148 #define MUX_C_NEW_STDIO_FWD 0x10000008
149 #define MUX_C_STOP_LISTENING 0x10000009
150 #define MUX_S_OK 0x80000001
151 #define MUX_S_PERMISSION_DENIED 0x80000002
152 #define MUX_S_FAILURE 0x80000003
153 #define MUX_S_EXIT_MESSAGE 0x80000004
154 #define MUX_S_ALIVE 0x80000005
155 #define MUX_S_SESSION_OPENED 0x80000006
156 #define MUX_S_REMOTE_PORT 0x80000007
157 #define MUX_S_TTY_ALLOC_FAIL 0x80000008
159 /* type codes for MUX_C_OPEN_FWD and MUX_C_CLOSE_FWD */
160 #define MUX_FWD_LOCAL 1
161 #define MUX_FWD_REMOTE 2
162 #define MUX_FWD_DYNAMIC 3
164 static void mux_session_confirm(int, int, void *);
165 static void mux_stdio_confirm(int, int, void *);
167 static int process_mux_master_hello(u_int, Channel *, Buffer *, Buffer *);
168 static int process_mux_new_session(u_int, Channel *, Buffer *, Buffer *);
169 static int process_mux_alive_check(u_int, Channel *, Buffer *, Buffer *);
170 static int process_mux_terminate(u_int, Channel *, Buffer *, Buffer *);
171 static int process_mux_open_fwd(u_int, Channel *, Buffer *, Buffer *);
172 static int process_mux_close_fwd(u_int, Channel *, Buffer *, Buffer *);
173 static int process_mux_stdio_fwd(u_int, Channel *, Buffer *, Buffer *);
174 static int process_mux_stop_listening(u_int, Channel *, Buffer *, Buffer *);
176 static const struct {
178 int (*handler)(u_int, Channel *, Buffer *, Buffer *);
179 } mux_master_handlers[] = {
180 { MUX_MSG_HELLO, process_mux_master_hello },
181 { MUX_C_NEW_SESSION, process_mux_new_session },
182 { MUX_C_ALIVE_CHECK, process_mux_alive_check },
183 { MUX_C_TERMINATE, process_mux_terminate },
184 { MUX_C_OPEN_FWD, process_mux_open_fwd },
185 { MUX_C_CLOSE_FWD, process_mux_close_fwd },
186 { MUX_C_NEW_STDIO_FWD, process_mux_stdio_fwd },
187 { MUX_C_STOP_LISTENING, process_mux_stop_listening },
191 /* Cleanup callback fired on closure of mux slave _session_ channel */
194 mux_master_session_cleanup_cb(int cid, void *unused)
196 Channel *cc, *c = channel_by_id(cid);
198 debug3("%s: entering for channel %d", __func__, cid);
200 fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
201 if (c->ctl_chan != -1) {
202 if ((cc = channel_by_id(c->ctl_chan)) == NULL)
203 fatal("%s: channel %d missing control channel %d",
204 __func__, c->self, c->ctl_chan);
207 chan_rcvd_oclose(cc);
209 channel_cancel_cleanup(c->self);
212 /* Cleanup callback fired on closure of mux slave _control_ channel */
215 mux_master_control_cleanup_cb(int cid, void *unused)
217 Channel *sc, *c = channel_by_id(cid);
219 debug3("%s: entering for channel %d", __func__, cid);
221 fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
222 if (c->remote_id != -1) {
223 if ((sc = channel_by_id(c->remote_id)) == NULL)
224 fatal("%s: channel %d missing session channel %d",
225 __func__, c->self, c->remote_id);
228 if (sc->type != SSH_CHANNEL_OPEN &&
229 sc->type != SSH_CHANNEL_OPENING) {
230 debug2("%s: channel %d: not open", __func__, sc->self);
233 if (sc->istate == CHAN_INPUT_OPEN)
234 chan_read_failed(sc);
235 if (sc->ostate == CHAN_OUTPUT_OPEN)
236 chan_write_failed(sc);
239 channel_cancel_cleanup(c->self);
242 /* Check mux client environment variables before passing them to mux master. */
244 env_permitted(char *env)
247 char name[1024], *cp;
249 if ((cp = strchr(env, '=')) == NULL || cp == env)
251 ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
252 if (ret <= 0 || (size_t)ret >= sizeof(name)) {
253 error("env_permitted: name '%.100s...' too long", env);
257 for (i = 0; i < options.num_send_env; i++)
258 if (match_pattern(name, options.send_env[i]))
264 /* Mux master protocol message handlers */
267 process_mux_master_hello(u_int rid, Channel *c, Buffer *m, Buffer *r)
270 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
273 fatal("%s: channel %d: c->mux_ctx == NULL", __func__, c->self);
274 if (state->hello_rcvd) {
275 error("%s: HELLO received twice", __func__);
278 if (buffer_get_int_ret(&ver, m) != 0) {
280 error("%s: malformed message", __func__);
283 if (ver != SSHMUX_VER) {
284 error("Unsupported multiplexing protocol version %d "
285 "(expected %d)", ver, SSHMUX_VER);
288 debug2("%s: channel %d slave version %u", __func__, c->self, ver);
290 /* No extensions are presently defined */
291 while (buffer_len(m) > 0) {
292 char *name = buffer_get_string_ret(m, NULL);
293 char *value = buffer_get_string_ret(m, NULL);
295 if (name == NULL || value == NULL) {
300 debug2("Unrecognised slave extension \"%s\"", name);
304 state->hello_rcvd = 1;
309 process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r)
312 struct mux_session_confirm_ctx *cctx;
313 char *reserved, *cmd, *cp;
314 u_int i, j, len, env_len, escape_char, window, packetmax;
317 /* Reply for SSHMUX_COMMAND_OPEN */
318 cctx = xcalloc(1, sizeof(*cctx));
321 cmd = reserved = NULL;
324 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
325 buffer_get_int_ret(&cctx->want_tty, m) != 0 ||
326 buffer_get_int_ret(&cctx->want_x_fwd, m) != 0 ||
327 buffer_get_int_ret(&cctx->want_agent_fwd, m) != 0 ||
328 buffer_get_int_ret(&cctx->want_subsys, m) != 0 ||
329 buffer_get_int_ret(&escape_char, m) != 0 ||
330 (cctx->term = buffer_get_string_ret(m, &len)) == NULL ||
331 (cmd = buffer_get_string_ret(m, &len)) == NULL) {
335 for (j = 0; j < env_len; j++)
340 error("%s: malformed message", __func__);
346 while (buffer_len(m) > 0) {
347 #define MUX_MAX_ENV_VARS 4096
348 if ((cp = buffer_get_string_ret(m, &len)) == NULL)
350 if (!env_permitted(cp)) {
354 cctx->env = xreallocarray(cctx->env, env_len + 2,
356 cctx->env[env_len++] = cp;
357 cctx->env[env_len] = NULL;
358 if (env_len > MUX_MAX_ENV_VARS) {
359 error(">%d environment variables received, ignoring "
360 "additional", MUX_MAX_ENV_VARS);
365 debug2("%s: channel %d: request tty %d, X %d, agent %d, subsys %d, "
366 "term \"%s\", cmd \"%s\", env %u", __func__, c->self,
367 cctx->want_tty, cctx->want_x_fwd, cctx->want_agent_fwd,
368 cctx->want_subsys, cctx->term, cmd, env_len);
370 buffer_init(&cctx->cmd);
371 buffer_append(&cctx->cmd, cmd, strlen(cmd));
375 /* Gather fds from client */
376 for(i = 0; i < 3; i++) {
377 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
378 error("%s: failed to receive fd %d from slave",
380 for (j = 0; j < i; j++)
382 for (j = 0; j < env_len; j++)
386 buffer_free(&cctx->cmd);
390 buffer_put_int(r, MUX_S_FAILURE);
391 buffer_put_int(r, rid);
392 buffer_put_cstring(r,
393 "did not receive file descriptors");
398 debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
399 new_fd[0], new_fd[1], new_fd[2]);
401 /* XXX support multiple child sessions in future */
402 if (c->remote_id != -1) {
403 debug2("%s: session already open", __func__);
405 buffer_put_int(r, MUX_S_FAILURE);
406 buffer_put_int(r, rid);
407 buffer_put_cstring(r, "Multiple sessions not supported");
414 for (i = 0; i < env_len; i++)
418 buffer_free(&cctx->cmd);
423 if (options.control_master == SSHCTL_MASTER_ASK ||
424 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
425 if (!ask_permission("Allow shared connection to %s? ", host)) {
426 debug2("%s: session refused by user", __func__);
428 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
429 buffer_put_int(r, rid);
430 buffer_put_cstring(r, "Permission denied");
435 /* Try to pick up ttymodes from client before it goes raw */
436 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
437 error("%s: tcgetattr: %s", __func__, strerror(errno));
439 /* enable nonblocking unless tty */
440 if (!isatty(new_fd[0]))
441 set_nonblock(new_fd[0]);
442 if (!isatty(new_fd[1]))
443 set_nonblock(new_fd[1]);
444 if (!isatty(new_fd[2]))
445 set_nonblock(new_fd[2]);
447 window = CHAN_SES_WINDOW_DEFAULT;
448 packetmax = CHAN_SES_PACKET_DEFAULT;
449 if (cctx->want_tty) {
454 nc = channel_new("session", SSH_CHANNEL_OPENING,
455 new_fd[0], new_fd[1], new_fd[2], window, packetmax,
456 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
458 nc->ctl_chan = c->self; /* link session -> control channel */
459 c->remote_id = nc->self; /* link control -> session channel */
461 if (cctx->want_tty && escape_char != 0xffffffff) {
462 channel_register_filter(nc->self,
463 client_simple_escape_filter, NULL,
464 client_filter_cleanup,
465 client_new_escape_filter_ctx((int)escape_char));
468 debug2("%s: channel_new: %d linked to control channel %d",
469 __func__, nc->self, nc->ctl_chan);
471 channel_send_open(nc->self);
472 channel_register_open_confirm(nc->self, mux_session_confirm, cctx);
473 c->mux_pause = 1; /* stop handling messages until open_confirm done */
474 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
476 /* reply is deferred, sent by mux_session_confirm */
481 process_mux_alive_check(u_int rid, Channel *c, Buffer *m, Buffer *r)
483 debug2("%s: channel %d: alive check", __func__, c->self);
486 buffer_put_int(r, MUX_S_ALIVE);
487 buffer_put_int(r, rid);
488 buffer_put_int(r, (u_int)getpid());
494 process_mux_terminate(u_int rid, Channel *c, Buffer *m, Buffer *r)
496 debug2("%s: channel %d: terminate request", __func__, c->self);
498 if (options.control_master == SSHCTL_MASTER_ASK ||
499 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
500 if (!ask_permission("Terminate shared connection to %s? ",
502 debug2("%s: termination refused by user", __func__);
503 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
504 buffer_put_int(r, rid);
505 buffer_put_cstring(r, "Permission denied");
511 buffer_put_int(r, MUX_S_OK);
512 buffer_put_int(r, rid);
513 /* XXX exit happens too soon - message never makes it to client */
518 format_forward(u_int ftype, struct Forward *fwd)
524 xasprintf(&ret, "local forward %.200s:%d -> %.200s:%d",
525 (fwd->listen_path != NULL) ? fwd->listen_path :
526 (fwd->listen_host == NULL) ?
527 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
528 fwd->listen_host, fwd->listen_port,
529 (fwd->connect_path != NULL) ? fwd->connect_path :
530 fwd->connect_host, fwd->connect_port);
532 case MUX_FWD_DYNAMIC:
533 xasprintf(&ret, "dynamic forward %.200s:%d -> *",
534 (fwd->listen_host == NULL) ?
535 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
536 fwd->listen_host, fwd->listen_port);
539 xasprintf(&ret, "remote forward %.200s:%d -> %.200s:%d",
540 (fwd->listen_path != NULL) ? fwd->listen_path :
541 (fwd->listen_host == NULL) ?
542 "LOCALHOST" : fwd->listen_host,
544 (fwd->connect_path != NULL) ? fwd->connect_path :
545 fwd->connect_host, fwd->connect_port);
548 fatal("%s: unknown forward type %u", __func__, ftype);
554 compare_host(const char *a, const char *b)
556 if (a == NULL && b == NULL)
558 if (a == NULL || b == NULL)
560 return strcmp(a, b) == 0;
564 compare_forward(struct Forward *a, struct Forward *b)
566 if (!compare_host(a->listen_host, b->listen_host))
568 if (!compare_host(a->listen_path, b->listen_path))
570 if (a->listen_port != b->listen_port)
572 if (!compare_host(a->connect_host, b->connect_host))
574 if (!compare_host(a->connect_path, b->connect_path))
576 if (a->connect_port != b->connect_port)
583 mux_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
585 struct mux_channel_confirm_ctx *fctx = ctxt;
586 char *failmsg = NULL;
587 struct Forward *rfwd;
591 if ((c = channel_by_id(fctx->cid)) == NULL) {
592 /* no channel for reply */
593 error("%s: unknown channel", __func__);
597 if (fctx->fid >= options.num_remote_forwards ||
598 (options.remote_forwards[fctx->fid].connect_path == NULL &&
599 options.remote_forwards[fctx->fid].connect_host == NULL)) {
600 xasprintf(&failmsg, "unknown forwarding id %d", fctx->fid);
603 rfwd = &options.remote_forwards[fctx->fid];
604 debug("%s: %s for: listen %d, connect %s:%d", __func__,
605 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
606 rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
607 rfwd->connect_host, rfwd->connect_port);
608 if (type == SSH2_MSG_REQUEST_SUCCESS) {
609 if (rfwd->listen_port == 0) {
610 rfwd->allocated_port = packet_get_int();
611 debug("Allocated port %u for mux remote forward"
612 " to %s:%d", rfwd->allocated_port,
613 rfwd->connect_host, rfwd->connect_port);
614 buffer_put_int(&out, MUX_S_REMOTE_PORT);
615 buffer_put_int(&out, fctx->rid);
616 buffer_put_int(&out, rfwd->allocated_port);
617 channel_update_permitted_opens(rfwd->handle,
618 rfwd->allocated_port);
620 buffer_put_int(&out, MUX_S_OK);
621 buffer_put_int(&out, fctx->rid);
625 if (rfwd->listen_port == 0)
626 channel_update_permitted_opens(rfwd->handle, -1);
627 if (rfwd->listen_path != NULL)
628 xasprintf(&failmsg, "remote port forwarding failed for "
629 "listen path %s", rfwd->listen_path);
631 xasprintf(&failmsg, "remote port forwarding failed for "
632 "listen port %d", rfwd->listen_port);
634 debug2("%s: clearing registered forwarding for listen %d, "
635 "connect %s:%d", __func__, rfwd->listen_port,
636 rfwd->connect_path ? rfwd->connect_path :
637 rfwd->connect_host, rfwd->connect_port);
639 free(rfwd->listen_host);
640 free(rfwd->listen_path);
641 free(rfwd->connect_host);
642 free(rfwd->connect_path);
643 memset(rfwd, 0, sizeof(*rfwd));
646 error("%s: %s", __func__, failmsg);
647 buffer_put_int(&out, MUX_S_FAILURE);
648 buffer_put_int(&out, fctx->rid);
649 buffer_put_cstring(&out, failmsg);
652 buffer_put_string(&c->output, buffer_ptr(&out), buffer_len(&out));
654 if (c->mux_pause <= 0)
655 fatal("%s: mux_pause %d", __func__, c->mux_pause);
656 c->mux_pause = 0; /* start processing messages again */
660 process_mux_open_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
663 char *fwd_desc = NULL;
664 char *listen_addr, *connect_addr;
667 int i, ret = 0, freefwd = 1;
669 memset(&fwd, 0, sizeof(fwd));
671 /* XXX - lport/cport check redundant */
672 if (buffer_get_int_ret(&ftype, m) != 0 ||
673 (listen_addr = buffer_get_string_ret(m, NULL)) == NULL ||
674 buffer_get_int_ret(&lport, m) != 0 ||
675 (connect_addr = buffer_get_string_ret(m, NULL)) == NULL ||
676 buffer_get_int_ret(&cport, m) != 0 ||
677 (lport != (u_int)PORT_STREAMLOCAL && lport > 65535) ||
678 (cport != (u_int)PORT_STREAMLOCAL && cport > 65535)) {
679 error("%s: malformed message", __func__);
683 if (*listen_addr == '\0') {
687 if (*connect_addr == '\0') {
692 memset(&fwd, 0, sizeof(fwd));
693 fwd.listen_port = lport;
694 if (fwd.listen_port == PORT_STREAMLOCAL)
695 fwd.listen_path = listen_addr;
697 fwd.listen_host = listen_addr;
698 fwd.connect_port = cport;
699 if (fwd.connect_port == PORT_STREAMLOCAL)
700 fwd.connect_path = connect_addr;
702 fwd.connect_host = connect_addr;
704 debug2("%s: channel %d: request %s", __func__, c->self,
705 (fwd_desc = format_forward(ftype, &fwd)));
707 if (ftype != MUX_FWD_LOCAL && ftype != MUX_FWD_REMOTE &&
708 ftype != MUX_FWD_DYNAMIC) {
709 logit("%s: invalid forwarding type %u", __func__, ftype);
713 buffer_put_int(r, MUX_S_FAILURE);
714 buffer_put_int(r, rid);
715 buffer_put_cstring(r, "Invalid forwarding request");
718 if (ftype == MUX_FWD_DYNAMIC && fwd.listen_path) {
719 logit("%s: streamlocal and dynamic forwards "
720 "are mutually exclusive", __func__);
723 if (fwd.listen_port != PORT_STREAMLOCAL && fwd.listen_port >= 65536) {
724 logit("%s: invalid listen port %u", __func__,
728 if ((fwd.connect_port != PORT_STREAMLOCAL && fwd.connect_port >= 65536)
729 || (ftype != MUX_FWD_DYNAMIC && ftype != MUX_FWD_REMOTE && fwd.connect_port == 0)) {
730 logit("%s: invalid connect port %u", __func__,
734 if (ftype != MUX_FWD_DYNAMIC && fwd.connect_host == NULL && fwd.connect_path == NULL) {
735 logit("%s: missing connect host", __func__);
739 /* Skip forwards that have already been requested */
742 case MUX_FWD_DYNAMIC:
743 for (i = 0; i < options.num_local_forwards; i++) {
744 if (compare_forward(&fwd,
745 options.local_forwards + i)) {
747 debug2("%s: found existing forwarding",
749 buffer_put_int(r, MUX_S_OK);
750 buffer_put_int(r, rid);
756 for (i = 0; i < options.num_remote_forwards; i++) {
757 if (compare_forward(&fwd,
758 options.remote_forwards + i)) {
759 if (fwd.listen_port != 0)
761 debug2("%s: found allocated port",
763 buffer_put_int(r, MUX_S_REMOTE_PORT);
764 buffer_put_int(r, rid);
766 options.remote_forwards[i].allocated_port);
773 if (options.control_master == SSHCTL_MASTER_ASK ||
774 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
775 if (!ask_permission("Open %s on %s?", fwd_desc, host)) {
776 debug2("%s: forwarding refused by user", __func__);
777 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
778 buffer_put_int(r, rid);
779 buffer_put_cstring(r, "Permission denied");
784 if (ftype == MUX_FWD_LOCAL || ftype == MUX_FWD_DYNAMIC) {
785 if (!channel_setup_local_fwd_listener(&fwd,
786 &options.fwd_opts)) {
788 logit("slave-requested %s failed", fwd_desc);
789 buffer_put_int(r, MUX_S_FAILURE);
790 buffer_put_int(r, rid);
791 buffer_put_cstring(r, "Port forwarding failed");
794 add_local_forward(&options, &fwd);
797 struct mux_channel_confirm_ctx *fctx;
799 fwd.handle = channel_request_remote_forwarding(&fwd);
802 add_remote_forward(&options, &fwd);
803 fctx = xcalloc(1, sizeof(*fctx));
806 fctx->fid = options.num_remote_forwards - 1;
807 client_register_global_confirm(mux_confirm_remote_forward,
810 c->mux_pause = 1; /* wait for mux_confirm_remote_forward */
811 /* delayed reply in mux_confirm_remote_forward */
814 buffer_put_int(r, MUX_S_OK);
815 buffer_put_int(r, rid);
819 free(fwd.listen_host);
820 free(fwd.listen_path);
821 free(fwd.connect_host);
822 free(fwd.connect_path);
828 process_mux_close_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
830 struct Forward fwd, *found_fwd;
831 char *fwd_desc = NULL;
832 const char *error_reason = NULL;
833 char *listen_addr = NULL, *connect_addr = NULL;
838 memset(&fwd, 0, sizeof(fwd));
840 if (buffer_get_int_ret(&ftype, m) != 0 ||
841 (listen_addr = buffer_get_string_ret(m, NULL)) == NULL ||
842 buffer_get_int_ret(&lport, m) != 0 ||
843 (connect_addr = buffer_get_string_ret(m, NULL)) == NULL ||
844 buffer_get_int_ret(&cport, m) != 0 ||
845 (lport != (u_int)PORT_STREAMLOCAL && lport > 65535) ||
846 (cport != (u_int)PORT_STREAMLOCAL && cport > 65535)) {
847 error("%s: malformed message", __func__);
852 if (*listen_addr == '\0') {
856 if (*connect_addr == '\0') {
861 memset(&fwd, 0, sizeof(fwd));
862 fwd.listen_port = lport;
863 if (fwd.listen_port == PORT_STREAMLOCAL)
864 fwd.listen_path = listen_addr;
866 fwd.listen_host = listen_addr;
867 fwd.connect_port = cport;
868 if (fwd.connect_port == PORT_STREAMLOCAL)
869 fwd.connect_path = connect_addr;
871 fwd.connect_host = connect_addr;
873 debug2("%s: channel %d: request cancel %s", __func__, c->self,
874 (fwd_desc = format_forward(ftype, &fwd)));
876 /* make sure this has been requested */
880 case MUX_FWD_DYNAMIC:
881 for (i = 0; i < options.num_local_forwards; i++) {
882 if (compare_forward(&fwd,
883 options.local_forwards + i)) {
884 found_fwd = options.local_forwards + i;
890 for (i = 0; i < options.num_remote_forwards; i++) {
891 if (compare_forward(&fwd,
892 options.remote_forwards + i)) {
893 found_fwd = options.remote_forwards + i;
900 if (found_fwd == NULL)
901 error_reason = "port not forwarded";
902 else if (ftype == MUX_FWD_REMOTE) {
904 * This shouldn't fail unless we confused the host/port
905 * between options.remote_forwards and permitted_opens.
906 * However, for dynamic allocated listen ports we need
907 * to use the actual listen port.
909 if (channel_request_rforward_cancel(found_fwd) == -1)
910 error_reason = "port not in permitted opens";
911 } else { /* local and dynamic forwards */
913 if (channel_cancel_lport_listener(&fwd, fwd.connect_port,
914 &options.fwd_opts) == -1)
915 error_reason = "port not found";
918 if (error_reason == NULL) {
919 buffer_put_int(r, MUX_S_OK);
920 buffer_put_int(r, rid);
922 free(found_fwd->listen_host);
923 free(found_fwd->listen_path);
924 free(found_fwd->connect_host);
925 free(found_fwd->connect_path);
926 found_fwd->listen_host = found_fwd->connect_host = NULL;
927 found_fwd->listen_path = found_fwd->connect_path = NULL;
928 found_fwd->listen_port = found_fwd->connect_port = 0;
930 buffer_put_int(r, MUX_S_FAILURE);
931 buffer_put_int(r, rid);
932 buffer_put_cstring(r, error_reason);
943 process_mux_stdio_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
946 char *reserved, *chost;
949 struct mux_stdio_confirm_ctx *cctx;
951 chost = reserved = NULL;
952 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
953 (chost = buffer_get_string_ret(m, NULL)) == NULL ||
954 buffer_get_int_ret(&cport, m) != 0) {
957 error("%s: malformed message", __func__);
962 debug2("%s: channel %d: request stdio fwd to %s:%u",
963 __func__, c->self, chost, cport);
965 /* Gather fds from client */
966 for(i = 0; i < 2; i++) {
967 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
968 error("%s: failed to receive fd %d from slave",
970 for (j = 0; j < i; j++)
975 buffer_put_int(r, MUX_S_FAILURE);
976 buffer_put_int(r, rid);
977 buffer_put_cstring(r,
978 "did not receive file descriptors");
983 debug3("%s: got fds stdin %d, stdout %d", __func__,
984 new_fd[0], new_fd[1]);
986 /* XXX support multiple child sessions in future */
987 if (c->remote_id != -1) {
988 debug2("%s: session already open", __func__);
990 buffer_put_int(r, MUX_S_FAILURE);
991 buffer_put_int(r, rid);
992 buffer_put_cstring(r, "Multiple sessions not supported");
1000 if (options.control_master == SSHCTL_MASTER_ASK ||
1001 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
1002 if (!ask_permission("Allow forward to %s:%u? ",
1004 debug2("%s: stdio fwd refused by user", __func__);
1006 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
1007 buffer_put_int(r, rid);
1008 buffer_put_cstring(r, "Permission denied");
1013 /* enable nonblocking unless tty */
1014 if (!isatty(new_fd[0]))
1015 set_nonblock(new_fd[0]);
1016 if (!isatty(new_fd[1]))
1017 set_nonblock(new_fd[1]);
1019 nc = channel_connect_stdio_fwd(chost, cport, new_fd[0], new_fd[1]);
1021 nc->ctl_chan = c->self; /* link session -> control channel */
1022 c->remote_id = nc->self; /* link control -> session channel */
1024 debug2("%s: channel_new: %d linked to control channel %d",
1025 __func__, nc->self, nc->ctl_chan);
1027 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
1029 cctx = xcalloc(1, sizeof(*cctx));
1031 channel_register_open_confirm(nc->self, mux_stdio_confirm, cctx);
1032 c->mux_pause = 1; /* stop handling messages until open_confirm done */
1034 /* reply is deferred, sent by mux_session_confirm */
1038 /* Callback on open confirmation in mux master for a mux stdio fwd session. */
1040 mux_stdio_confirm(int id, int success, void *arg)
1042 struct mux_stdio_confirm_ctx *cctx = arg;
1047 fatal("%s: cctx == NULL", __func__);
1048 if ((c = channel_by_id(id)) == NULL)
1049 fatal("%s: no channel for id %d", __func__, id);
1050 if ((cc = channel_by_id(c->ctl_chan)) == NULL)
1051 fatal("%s: channel %d lacks control channel %d", __func__,
1055 debug3("%s: sending failure reply", __func__);
1057 buffer_init(&reply);
1058 buffer_put_int(&reply, MUX_S_FAILURE);
1059 buffer_put_int(&reply, cctx->rid);
1060 buffer_put_cstring(&reply, "Session open refused by peer");
1064 debug3("%s: sending success reply", __func__);
1066 buffer_init(&reply);
1067 buffer_put_int(&reply, MUX_S_SESSION_OPENED);
1068 buffer_put_int(&reply, cctx->rid);
1069 buffer_put_int(&reply, c->self);
1073 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
1074 buffer_free(&reply);
1076 if (cc->mux_pause <= 0)
1077 fatal("%s: mux_pause %d", __func__, cc->mux_pause);
1078 cc->mux_pause = 0; /* start processing messages again */
1079 c->open_confirm_ctx = NULL;
1084 process_mux_stop_listening(u_int rid, Channel *c, Buffer *m, Buffer *r)
1086 debug("%s: channel %d: stop listening", __func__, c->self);
1088 if (options.control_master == SSHCTL_MASTER_ASK ||
1089 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
1090 if (!ask_permission("Disable further multiplexing on shared "
1091 "connection to %s? ", host)) {
1092 debug2("%s: stop listen refused by user", __func__);
1093 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
1094 buffer_put_int(r, rid);
1095 buffer_put_cstring(r, "Permission denied");
1100 if (mux_listener_channel != NULL) {
1101 channel_free(mux_listener_channel);
1103 free(options.control_path);
1104 options.control_path = NULL;
1105 mux_listener_channel = NULL;
1106 muxserver_sock = -1;
1110 buffer_put_int(r, MUX_S_OK);
1111 buffer_put_int(r, rid);
1116 /* Channel callbacks fired on read/write from mux slave fd */
1118 mux_master_read_cb(Channel *c)
1120 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
1123 u_int type, rid, have, i;
1127 if (c->mux_ctx == NULL) {
1128 state = xcalloc(1, sizeof(*state));
1130 channel_register_cleanup(c->self,
1131 mux_master_control_cleanup_cb, 0);
1135 buffer_put_int(&out, MUX_MSG_HELLO);
1136 buffer_put_int(&out, SSHMUX_VER);
1138 buffer_put_string(&c->output, buffer_ptr(&out),
1141 debug3("%s: channel %d: hello sent", __func__, c->self);
1148 /* Channel code ensures that we receive whole packets */
1149 if ((ptr = buffer_get_string_ptr_ret(&c->input, &have)) == NULL) {
1151 error("%s: malformed message", __func__);
1154 buffer_append(&in, ptr, have);
1156 if (buffer_get_int_ret(&type, &in) != 0)
1158 debug3("%s: channel %d packet type 0x%08x len %u",
1159 __func__, c->self, type, buffer_len(&in));
1161 if (type == MUX_MSG_HELLO)
1164 if (!state->hello_rcvd) {
1165 error("%s: expected MUX_MSG_HELLO(0x%08x), "
1166 "received 0x%08x", __func__, MUX_MSG_HELLO, type);
1169 if (buffer_get_int_ret(&rid, &in) != 0)
1173 for (i = 0; mux_master_handlers[i].handler != NULL; i++) {
1174 if (type == mux_master_handlers[i].type) {
1175 ret = mux_master_handlers[i].handler(rid, c, &in, &out);
1179 if (mux_master_handlers[i].handler == NULL) {
1180 error("%s: unsupported mux message 0x%08x", __func__, type);
1181 buffer_put_int(&out, MUX_S_FAILURE);
1182 buffer_put_int(&out, rid);
1183 buffer_put_cstring(&out, "unsupported request");
1186 /* Enqueue reply packet */
1187 if (buffer_len(&out) != 0) {
1188 buffer_put_string(&c->output, buffer_ptr(&out),
1198 mux_exit_message(Channel *c, int exitval)
1203 debug3("%s: channel %d: exit message, exitval %d", __func__, c->self,
1206 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL)
1207 fatal("%s: channel %d missing mux channel %d",
1208 __func__, c->self, c->ctl_chan);
1210 /* Append exit message packet to control socket output queue */
1212 buffer_put_int(&m, MUX_S_EXIT_MESSAGE);
1213 buffer_put_int(&m, c->self);
1214 buffer_put_int(&m, exitval);
1216 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1221 mux_tty_alloc_failed(Channel *c)
1226 debug3("%s: channel %d: TTY alloc failed", __func__, c->self);
1228 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL)
1229 fatal("%s: channel %d missing mux channel %d",
1230 __func__, c->self, c->ctl_chan);
1232 /* Append exit message packet to control socket output queue */
1234 buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL);
1235 buffer_put_int(&m, c->self);
1237 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1241 /* Prepare a mux master to listen on a Unix domain socket. */
1243 muxserver_listen(void)
1246 char *orig_control_path = options.control_path;
1251 if (options.control_path == NULL ||
1252 options.control_master == SSHCTL_MASTER_NO)
1255 debug("setting up multiplex master socket");
1258 * Use a temporary path before listen so we can pseudo-atomically
1259 * establish the listening socket in its final location to avoid
1260 * other processes racing in between bind() and listen() and hitting
1261 * an unready socket.
1263 for (i = 0; i < sizeof(rbuf) - 1; i++) {
1264 r = arc4random_uniform(26+26+10);
1265 rbuf[i] = (r < 26) ? 'a' + r :
1266 (r < 26*2) ? 'A' + r - 26 :
1269 rbuf[sizeof(rbuf) - 1] = '\0';
1270 options.control_path = NULL;
1271 xasprintf(&options.control_path, "%s.%s", orig_control_path, rbuf);
1272 debug3("%s: temporary control path %s", __func__, options.control_path);
1274 old_umask = umask(0177);
1275 muxserver_sock = unix_listener(options.control_path, 64, 0);
1278 if (muxserver_sock < 0) {
1279 if (oerrno == EINVAL || oerrno == EADDRINUSE) {
1280 error("ControlSocket %s already exists, "
1281 "disabling multiplexing", options.control_path);
1283 if (muxserver_sock != -1) {
1284 close(muxserver_sock);
1285 muxserver_sock = -1;
1287 free(orig_control_path);
1288 free(options.control_path);
1289 options.control_path = NULL;
1290 options.control_master = SSHCTL_MASTER_NO;
1293 /* unix_listener() logs the error */
1298 /* Now atomically "move" the mux socket into position */
1299 if (link(options.control_path, orig_control_path) != 0) {
1300 if (errno != EEXIST) {
1301 fatal("%s: link mux listener %s => %s: %s", __func__,
1302 options.control_path, orig_control_path,
1305 error("ControlSocket %s already exists, disabling multiplexing",
1307 unlink(options.control_path);
1308 goto disable_mux_master;
1310 unlink(options.control_path);
1311 free(options.control_path);
1312 options.control_path = orig_control_path;
1314 set_nonblock(muxserver_sock);
1316 mux_listener_channel = channel_new("mux listener",
1317 SSH_CHANNEL_MUX_LISTENER, muxserver_sock, muxserver_sock, -1,
1318 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1319 0, options.control_path, 1);
1320 mux_listener_channel->mux_rcb = mux_master_read_cb;
1321 debug3("%s: mux listener channel %d fd %d", __func__,
1322 mux_listener_channel->self, mux_listener_channel->sock);
1325 /* Callback on open confirmation in mux master for a mux client session. */
1327 mux_session_confirm(int id, int success, void *arg)
1329 struct mux_session_confirm_ctx *cctx = arg;
1330 const char *display;
1336 fatal("%s: cctx == NULL", __func__);
1337 if ((c = channel_by_id(id)) == NULL)
1338 fatal("%s: no channel for id %d", __func__, id);
1339 if ((cc = channel_by_id(c->ctl_chan)) == NULL)
1340 fatal("%s: channel %d lacks control channel %d", __func__,
1344 debug3("%s: sending failure reply", __func__);
1346 buffer_init(&reply);
1347 buffer_put_int(&reply, MUX_S_FAILURE);
1348 buffer_put_int(&reply, cctx->rid);
1349 buffer_put_cstring(&reply, "Session open refused by peer");
1353 display = getenv("DISPLAY");
1354 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
1357 /* Get reasonable local authentication information. */
1358 if (client_x11_get_proto(display, options.xauth_location,
1359 options.forward_x11_trusted, options.forward_x11_timeout,
1360 &proto, &data) == 0) {
1361 /* Request forwarding with authentication spoofing. */
1362 debug("Requesting X11 forwarding with authentication "
1364 x11_request_forwarding_with_spoofing(id, display, proto,
1366 /* XXX exit_on_forward_failure */
1367 client_expect_confirm(id, "X11 forwarding",
1372 if (cctx->want_agent_fwd && options.forward_agent) {
1373 debug("Requesting authentication agent forwarding.");
1374 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1378 client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
1379 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env);
1381 debug3("%s: sending success reply", __func__);
1383 buffer_init(&reply);
1384 buffer_put_int(&reply, MUX_S_SESSION_OPENED);
1385 buffer_put_int(&reply, cctx->rid);
1386 buffer_put_int(&reply, c->self);
1390 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
1391 buffer_free(&reply);
1393 if (cc->mux_pause <= 0)
1394 fatal("%s: mux_pause %d", __func__, cc->mux_pause);
1395 cc->mux_pause = 0; /* start processing messages again */
1396 c->open_confirm_ctx = NULL;
1397 buffer_free(&cctx->cmd);
1399 if (cctx->env != NULL) {
1400 for (i = 0; cctx->env[i] != NULL; i++)
1407 /* ** Multiplexing client support */
1409 /* Exit signal handler */
1411 control_client_sighandler(int signo)
1413 muxclient_terminate = signo;
1417 * Relay signal handler - used to pass some signals from mux client to
1421 control_client_sigrelay(int signo)
1423 int save_errno = errno;
1425 if (muxserver_pid > 1)
1426 kill(muxserver_pid, signo);
1432 mux_client_read(int fd, Buffer *b, u_int need)
1440 pfd.events = POLLIN;
1441 p = buffer_append_space(b, need);
1442 for (have = 0; have < need; ) {
1443 if (muxclient_terminate) {
1447 len = read(fd, p + have, need - have);
1450 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1454 (void)poll(&pfd, 1, -1);
1472 mux_client_write_packet(int fd, Buffer *m)
1481 pfd.events = POLLOUT;
1482 buffer_init(&queue);
1483 buffer_put_string(&queue, buffer_ptr(m), buffer_len(m));
1485 need = buffer_len(&queue);
1486 ptr = buffer_ptr(&queue);
1488 for (have = 0; have < need; ) {
1489 if (muxclient_terminate) {
1490 buffer_free(&queue);
1494 len = write(fd, ptr + have, need - have);
1497 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1501 (void)poll(&pfd, 1, -1);
1507 buffer_free(&queue);
1513 buffer_free(&queue);
1519 buffer_free(&queue);
1524 mux_client_read_packet(int fd, Buffer *m)
1531 buffer_init(&queue);
1532 if (mux_client_read(fd, &queue, 4) != 0) {
1533 if ((oerrno = errno) == EPIPE)
1534 debug3("%s: read header failed: %s", __func__,
1536 buffer_free(&queue);
1540 need = get_u32(buffer_ptr(&queue));
1541 if (mux_client_read(fd, &queue, need) != 0) {
1543 debug3("%s: read body failed: %s", __func__, strerror(errno));
1544 buffer_free(&queue);
1548 ptr = buffer_get_string_ptr(&queue, &have);
1549 buffer_append(m, ptr, have);
1550 buffer_free(&queue);
1555 mux_client_hello_exchange(int fd)
1561 buffer_put_int(&m, MUX_MSG_HELLO);
1562 buffer_put_int(&m, SSHMUX_VER);
1565 if (mux_client_write_packet(fd, &m) != 0)
1566 fatal("%s: write packet: %s", __func__, strerror(errno));
1570 /* Read their HELLO */
1571 if (mux_client_read_packet(fd, &m) != 0) {
1576 type = buffer_get_int(&m);
1577 if (type != MUX_MSG_HELLO)
1578 fatal("%s: expected HELLO (%u) received %u",
1579 __func__, MUX_MSG_HELLO, type);
1580 ver = buffer_get_int(&m);
1581 if (ver != SSHMUX_VER)
1582 fatal("Unsupported multiplexing protocol version %d "
1583 "(expected %d)", ver, SSHMUX_VER);
1584 debug2("%s: master version %u", __func__, ver);
1585 /* No extensions are presently defined */
1586 while (buffer_len(&m) > 0) {
1587 char *name = buffer_get_string(&m, NULL);
1588 char *value = buffer_get_string(&m, NULL);
1590 debug2("Unrecognised master extension \"%s\"", name);
1599 mux_client_request_alive(int fd)
1603 u_int pid, type, rid;
1605 debug3("%s: entering", __func__);
1608 buffer_put_int(&m, MUX_C_ALIVE_CHECK);
1609 buffer_put_int(&m, muxclient_request_id);
1611 if (mux_client_write_packet(fd, &m) != 0)
1612 fatal("%s: write packet: %s", __func__, strerror(errno));
1616 /* Read their reply */
1617 if (mux_client_read_packet(fd, &m) != 0) {
1622 type = buffer_get_int(&m);
1623 if (type != MUX_S_ALIVE) {
1624 e = buffer_get_string(&m, NULL);
1625 fatal("%s: master returned error: %s", __func__, e);
1628 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1629 fatal("%s: out of sequence reply: my id %u theirs %u",
1630 __func__, muxclient_request_id, rid);
1631 pid = buffer_get_int(&m);
1634 debug3("%s: done pid = %u", __func__, pid);
1636 muxclient_request_id++;
1642 mux_client_request_terminate(int fd)
1648 debug3("%s: entering", __func__);
1651 buffer_put_int(&m, MUX_C_TERMINATE);
1652 buffer_put_int(&m, muxclient_request_id);
1654 if (mux_client_write_packet(fd, &m) != 0)
1655 fatal("%s: write packet: %s", __func__, strerror(errno));
1659 /* Read their reply */
1660 if (mux_client_read_packet(fd, &m) != 0) {
1661 /* Remote end exited already */
1662 if (errno == EPIPE) {
1666 fatal("%s: read from master failed: %s",
1667 __func__, strerror(errno));
1670 type = buffer_get_int(&m);
1671 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1672 fatal("%s: out of sequence reply: my id %u theirs %u",
1673 __func__, muxclient_request_id, rid);
1677 case MUX_S_PERMISSION_DENIED:
1678 e = buffer_get_string(&m, NULL);
1679 fatal("Master refused termination request: %s", e);
1681 e = buffer_get_string(&m, NULL);
1682 fatal("%s: termination request failed: %s", __func__, e);
1684 fatal("%s: unexpected response from master 0x%08x",
1688 muxclient_request_id++;
1692 mux_client_forward(int fd, int cancel_flag, u_int ftype, struct Forward *fwd)
1698 fwd_desc = format_forward(ftype, fwd);
1699 debug("Requesting %s %s",
1700 cancel_flag ? "cancellation of" : "forwarding of", fwd_desc);
1704 buffer_put_int(&m, cancel_flag ? MUX_C_CLOSE_FWD : MUX_C_OPEN_FWD);
1705 buffer_put_int(&m, muxclient_request_id);
1706 buffer_put_int(&m, ftype);
1707 if (fwd->listen_path != NULL) {
1708 buffer_put_cstring(&m, fwd->listen_path);
1710 buffer_put_cstring(&m,
1711 fwd->listen_host == NULL ? "" :
1712 (*fwd->listen_host == '\0' ? "*" : fwd->listen_host));
1714 buffer_put_int(&m, fwd->listen_port);
1715 if (fwd->connect_path != NULL) {
1716 buffer_put_cstring(&m, fwd->connect_path);
1718 buffer_put_cstring(&m,
1719 fwd->connect_host == NULL ? "" : fwd->connect_host);
1721 buffer_put_int(&m, fwd->connect_port);
1723 if (mux_client_write_packet(fd, &m) != 0)
1724 fatal("%s: write packet: %s", __func__, strerror(errno));
1728 /* Read their reply */
1729 if (mux_client_read_packet(fd, &m) != 0) {
1734 type = buffer_get_int(&m);
1735 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1736 fatal("%s: out of sequence reply: my id %u theirs %u",
1737 __func__, muxclient_request_id, rid);
1741 case MUX_S_REMOTE_PORT:
1743 fatal("%s: got MUX_S_REMOTE_PORT for cancel", __func__);
1744 fwd->allocated_port = buffer_get_int(&m);
1745 verbose("Allocated port %u for remote forward to %s:%d",
1746 fwd->allocated_port,
1747 fwd->connect_host ? fwd->connect_host : "",
1749 if (muxclient_command == SSHMUX_COMMAND_FORWARD)
1750 fprintf(stdout, "%i\n", fwd->allocated_port);
1752 case MUX_S_PERMISSION_DENIED:
1753 e = buffer_get_string(&m, NULL);
1755 error("Master refused forwarding request: %s", e);
1758 e = buffer_get_string(&m, NULL);
1760 error("%s: forwarding request failed: %s", __func__, e);
1763 fatal("%s: unexpected response from master 0x%08x",
1768 muxclient_request_id++;
1773 mux_client_forwards(int fd, int cancel_flag)
1777 debug3("%s: %s forwardings: %d local, %d remote", __func__,
1778 cancel_flag ? "cancel" : "request",
1779 options.num_local_forwards, options.num_remote_forwards);
1781 /* XXX ExitOnForwardingFailure */
1782 for (i = 0; i < options.num_local_forwards; i++) {
1783 if (mux_client_forward(fd, cancel_flag,
1784 options.local_forwards[i].connect_port == 0 ?
1785 MUX_FWD_DYNAMIC : MUX_FWD_LOCAL,
1786 options.local_forwards + i) != 0)
1789 for (i = 0; i < options.num_remote_forwards; i++) {
1790 if (mux_client_forward(fd, cancel_flag, MUX_FWD_REMOTE,
1791 options.remote_forwards + i) != 0)
1798 mux_client_request_session(int fd)
1802 u_int i, rid, sid, esid, exitval, type, exitval_seen;
1803 extern char **environ;
1804 int devnull, rawmode;
1806 debug3("%s: entering", __func__);
1808 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
1809 error("%s: master alive request failed", __func__);
1813 signal(SIGPIPE, SIG_IGN);
1815 if (stdin_null_flag) {
1816 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1817 fatal("open(/dev/null): %s", strerror(errno));
1818 if (dup2(devnull, STDIN_FILENO) == -1)
1819 fatal("dup2: %s", strerror(errno));
1820 if (devnull > STDERR_FILENO)
1824 term = getenv("TERM");
1827 buffer_put_int(&m, MUX_C_NEW_SESSION);
1828 buffer_put_int(&m, muxclient_request_id);
1829 buffer_put_cstring(&m, ""); /* reserved */
1830 buffer_put_int(&m, tty_flag);
1831 buffer_put_int(&m, options.forward_x11);
1832 buffer_put_int(&m, options.forward_agent);
1833 buffer_put_int(&m, subsystem_flag);
1834 buffer_put_int(&m, options.escape_char == SSH_ESCAPECHAR_NONE ?
1835 0xffffffff : (u_int)options.escape_char);
1836 buffer_put_cstring(&m, term == NULL ? "" : term);
1837 buffer_put_string(&m, buffer_ptr(&command), buffer_len(&command));
1839 if (options.num_send_env > 0 && environ != NULL) {
1840 /* Pass environment */
1841 for (i = 0; environ[i] != NULL; i++) {
1842 if (env_permitted(environ[i])) {
1843 buffer_put_cstring(&m, environ[i]);
1848 if (mux_client_write_packet(fd, &m) != 0)
1849 fatal("%s: write packet: %s", __func__, strerror(errno));
1851 /* Send the stdio file descriptors */
1852 if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
1853 mm_send_fd(fd, STDOUT_FILENO) == -1 ||
1854 mm_send_fd(fd, STDERR_FILENO) == -1)
1855 fatal("%s: send fds failed", __func__);
1857 debug3("%s: session request sent", __func__);
1859 /* Read their reply */
1861 if (mux_client_read_packet(fd, &m) != 0) {
1862 error("%s: read from master failed: %s",
1863 __func__, strerror(errno));
1868 type = buffer_get_int(&m);
1869 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1870 fatal("%s: out of sequence reply: my id %u theirs %u",
1871 __func__, muxclient_request_id, rid);
1873 case MUX_S_SESSION_OPENED:
1874 sid = buffer_get_int(&m);
1875 debug("%s: master session id: %u", __func__, sid);
1877 case MUX_S_PERMISSION_DENIED:
1878 e = buffer_get_string(&m, NULL);
1880 error("Master refused session request: %s", e);
1883 e = buffer_get_string(&m, NULL);
1885 error("%s: session request failed: %s", __func__, e);
1889 error("%s: unexpected response from master 0x%08x",
1893 muxclient_request_id++;
1895 if (pledge("stdio proc tty", NULL) == -1)
1896 fatal("%s pledge(): %s", __func__, strerror(errno));
1897 platform_pledge_mux();
1899 signal(SIGHUP, control_client_sighandler);
1900 signal(SIGINT, control_client_sighandler);
1901 signal(SIGTERM, control_client_sighandler);
1902 signal(SIGWINCH, control_client_sigrelay);
1906 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1909 * Stick around until the controlee closes the client_fd.
1910 * Before it does, it is expected to write an exit message.
1911 * This process must read the value and wait for the closure of
1912 * the client_fd; if this one closes early, the multiplex master will
1913 * terminate early too (possibly losing data).
1915 for (exitval = 255, exitval_seen = 0;;) {
1917 if (mux_client_read_packet(fd, &m) != 0)
1919 type = buffer_get_int(&m);
1921 case MUX_S_TTY_ALLOC_FAIL:
1922 if ((esid = buffer_get_int(&m)) != sid)
1923 fatal("%s: tty alloc fail on unknown session: "
1924 "my id %u theirs %u",
1925 __func__, sid, esid);
1926 leave_raw_mode(options.request_tty ==
1930 case MUX_S_EXIT_MESSAGE:
1931 if ((esid = buffer_get_int(&m)) != sid)
1932 fatal("%s: exit on unknown session: "
1933 "my id %u theirs %u",
1934 __func__, sid, esid);
1936 fatal("%s: exitval sent twice", __func__);
1937 exitval = buffer_get_int(&m);
1941 e = buffer_get_string(&m, NULL);
1942 fatal("%s: master returned error: %s", __func__, e);
1948 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1950 if (muxclient_terminate) {
1951 debug2("Exiting on signal %ld", (long)muxclient_terminate);
1953 } else if (!exitval_seen) {
1954 debug2("Control master terminated unexpectedly");
1957 debug2("Received exit status from master %d", exitval);
1959 if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1960 fprintf(stderr, "Shared connection to %s closed.\r\n", host);
1966 mux_client_request_stdio_fwd(int fd)
1970 u_int type, rid, sid;
1973 debug3("%s: entering", __func__);
1975 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
1976 error("%s: master alive request failed", __func__);
1980 signal(SIGPIPE, SIG_IGN);
1982 if (stdin_null_flag) {
1983 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1984 fatal("open(/dev/null): %s", strerror(errno));
1985 if (dup2(devnull, STDIN_FILENO) == -1)
1986 fatal("dup2: %s", strerror(errno));
1987 if (devnull > STDERR_FILENO)
1992 buffer_put_int(&m, MUX_C_NEW_STDIO_FWD);
1993 buffer_put_int(&m, muxclient_request_id);
1994 buffer_put_cstring(&m, ""); /* reserved */
1995 buffer_put_cstring(&m, stdio_forward_host);
1996 buffer_put_int(&m, stdio_forward_port);
1998 if (mux_client_write_packet(fd, &m) != 0)
1999 fatal("%s: write packet: %s", __func__, strerror(errno));
2001 /* Send the stdio file descriptors */
2002 if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
2003 mm_send_fd(fd, STDOUT_FILENO) == -1)
2004 fatal("%s: send fds failed", __func__);
2006 if (pledge("stdio proc tty", NULL) == -1)
2007 fatal("%s pledge(): %s", __func__, strerror(errno));
2008 platform_pledge_mux();
2010 debug3("%s: stdio forward request sent", __func__);
2012 /* Read their reply */
2015 if (mux_client_read_packet(fd, &m) != 0) {
2016 error("%s: read from master failed: %s",
2017 __func__, strerror(errno));
2022 type = buffer_get_int(&m);
2023 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
2024 fatal("%s: out of sequence reply: my id %u theirs %u",
2025 __func__, muxclient_request_id, rid);
2027 case MUX_S_SESSION_OPENED:
2028 sid = buffer_get_int(&m);
2029 debug("%s: master session id: %u", __func__, sid);
2031 case MUX_S_PERMISSION_DENIED:
2032 e = buffer_get_string(&m, NULL);
2034 fatal("Master refused stdio forwarding request: %s", e);
2036 e = buffer_get_string(&m, NULL);
2038 fatal("Stdio forwarding request failed: %s", e);
2041 error("%s: unexpected response from master 0x%08x",
2045 muxclient_request_id++;
2047 signal(SIGHUP, control_client_sighandler);
2048 signal(SIGINT, control_client_sighandler);
2049 signal(SIGTERM, control_client_sighandler);
2050 signal(SIGWINCH, control_client_sigrelay);
2053 * Stick around until the controlee closes the client_fd.
2056 if (mux_client_read_packet(fd, &m) != 0) {
2057 if (errno == EPIPE ||
2058 (errno == EINTR && muxclient_terminate != 0))
2060 fatal("%s: mux_client_read_packet: %s",
2061 __func__, strerror(errno));
2063 fatal("%s: master returned unexpected message %u", __func__, type);
2067 mux_client_request_stop_listening(int fd)
2073 debug3("%s: entering", __func__);
2076 buffer_put_int(&m, MUX_C_STOP_LISTENING);
2077 buffer_put_int(&m, muxclient_request_id);
2079 if (mux_client_write_packet(fd, &m) != 0)
2080 fatal("%s: write packet: %s", __func__, strerror(errno));
2084 /* Read their reply */
2085 if (mux_client_read_packet(fd, &m) != 0)
2086 fatal("%s: read from master failed: %s",
2087 __func__, strerror(errno));
2089 type = buffer_get_int(&m);
2090 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
2091 fatal("%s: out of sequence reply: my id %u theirs %u",
2092 __func__, muxclient_request_id, rid);
2096 case MUX_S_PERMISSION_DENIED:
2097 e = buffer_get_string(&m, NULL);
2098 fatal("Master refused stop listening request: %s", e);
2100 e = buffer_get_string(&m, NULL);
2101 fatal("%s: stop listening request failed: %s", __func__, e);
2103 fatal("%s: unexpected response from master 0x%08x",
2107 muxclient_request_id++;
2110 /* Multiplex client main loop. */
2112 muxclient(const char *path)
2114 struct sockaddr_un addr;
2119 if (muxclient_command == 0) {
2120 if (stdio_forward_host != NULL)
2121 muxclient_command = SSHMUX_COMMAND_STDIO_FWD;
2123 muxclient_command = SSHMUX_COMMAND_OPEN;
2126 switch (options.control_master) {
2127 case SSHCTL_MASTER_AUTO:
2128 case SSHCTL_MASTER_AUTO_ASK:
2129 debug("auto-mux: Trying existing master");
2131 case SSHCTL_MASTER_NO:
2137 memset(&addr, '\0', sizeof(addr));
2138 addr.sun_family = AF_UNIX;
2139 sun_len = offsetof(struct sockaddr_un, sun_path) +
2142 if (strlcpy(addr.sun_path, path,
2143 sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
2144 fatal("ControlPath too long");
2146 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
2147 fatal("%s socket(): %s", __func__, strerror(errno));
2149 if (connect(sock, (struct sockaddr *)&addr, sun_len) == -1) {
2150 switch (muxclient_command) {
2151 case SSHMUX_COMMAND_OPEN:
2152 case SSHMUX_COMMAND_STDIO_FWD:
2155 fatal("Control socket connect(%.100s): %s", path,
2158 if (errno == ECONNREFUSED &&
2159 options.control_master != SSHCTL_MASTER_NO) {
2160 debug("Stale control socket %.100s, unlinking", path);
2162 } else if (errno == ENOENT) {
2163 debug("Control socket \"%.100s\" does not exist", path);
2165 error("Control socket connect(%.100s): %s", path,
2173 if (mux_client_hello_exchange(sock) != 0) {
2174 error("%s: master hello exchange failed", __func__);
2179 switch (muxclient_command) {
2180 case SSHMUX_COMMAND_ALIVE_CHECK:
2181 if ((pid = mux_client_request_alive(sock)) == 0)
2182 fatal("%s: master alive check failed", __func__);
2183 fprintf(stderr, "Master running (pid=%u)\r\n", pid);
2185 case SSHMUX_COMMAND_TERMINATE:
2186 mux_client_request_terminate(sock);
2187 fprintf(stderr, "Exit request sent.\r\n");
2189 case SSHMUX_COMMAND_FORWARD:
2190 if (mux_client_forwards(sock, 0) != 0)
2191 fatal("%s: master forward request failed", __func__);
2193 case SSHMUX_COMMAND_OPEN:
2194 if (mux_client_forwards(sock, 0) != 0) {
2195 error("%s: master forward request failed", __func__);
2198 mux_client_request_session(sock);
2200 case SSHMUX_COMMAND_STDIO_FWD:
2201 mux_client_request_stdio_fwd(sock);
2203 case SSHMUX_COMMAND_STOP:
2204 mux_client_request_stop_listening(sock);
2205 fprintf(stderr, "Stop listening request sent.\r\n");
2207 case SSHMUX_COMMAND_CANCEL_FWD:
2208 if (mux_client_forwards(sock, 1) != 0)
2209 error("%s: master cancel forward request failed",
2213 fatal("unrecognised muxclient_command %d", muxclient_command);