1 /* $OpenBSD: mux.c,v 1.60 2016/06/03 03:14:41 dtucker 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
;
92 /* Context for session open confirmation callback */
93 struct mux_session_confirm_ctx
{
105 /* Context for stdio fwd open confirmation callback */
106 struct mux_stdio_confirm_ctx
{
110 /* Context for global channel callback */
111 struct mux_channel_confirm_ctx
{
112 u_int cid
; /* channel id */
113 u_int rid
; /* request id */
114 int fid
; /* forward id */
117 /* fd to control socket */
118 int muxserver_sock
= -1;
120 /* client request id */
121 u_int muxclient_request_id
= 0;
123 /* Multiplexing control command */
124 u_int muxclient_command
= 0;
126 /* Set when signalled. */
127 static volatile sig_atomic_t muxclient_terminate
= 0;
129 /* PID of multiplex server */
130 static u_int muxserver_pid
= 0;
132 static Channel
*mux_listener_channel
= NULL
;
134 struct mux_master_state
{
138 /* mux protocol messages */
139 #define MUX_MSG_HELLO 0x00000001
140 #define MUX_C_NEW_SESSION 0x10000002
141 #define MUX_C_ALIVE_CHECK 0x10000004
142 #define MUX_C_TERMINATE 0x10000005
143 #define MUX_C_OPEN_FWD 0x10000006
144 #define MUX_C_CLOSE_FWD 0x10000007
145 #define MUX_C_NEW_STDIO_FWD 0x10000008
146 #define MUX_C_STOP_LISTENING 0x10000009
147 #define MUX_S_OK 0x80000001
148 #define MUX_S_PERMISSION_DENIED 0x80000002
149 #define MUX_S_FAILURE 0x80000003
150 #define MUX_S_EXIT_MESSAGE 0x80000004
151 #define MUX_S_ALIVE 0x80000005
152 #define MUX_S_SESSION_OPENED 0x80000006
153 #define MUX_S_REMOTE_PORT 0x80000007
154 #define MUX_S_TTY_ALLOC_FAIL 0x80000008
156 /* type codes for MUX_C_OPEN_FWD and MUX_C_CLOSE_FWD */
157 #define MUX_FWD_LOCAL 1
158 #define MUX_FWD_REMOTE 2
159 #define MUX_FWD_DYNAMIC 3
161 static void mux_session_confirm(int, int, void *);
162 static void mux_stdio_confirm(int, int, void *);
164 static int process_mux_master_hello(u_int
, Channel
*, Buffer
*, Buffer
*);
165 static int process_mux_new_session(u_int
, Channel
*, Buffer
*, Buffer
*);
166 static int process_mux_alive_check(u_int
, Channel
*, Buffer
*, Buffer
*);
167 static int process_mux_terminate(u_int
, Channel
*, Buffer
*, Buffer
*);
168 static int process_mux_open_fwd(u_int
, Channel
*, Buffer
*, Buffer
*);
169 static int process_mux_close_fwd(u_int
, Channel
*, Buffer
*, Buffer
*);
170 static int process_mux_stdio_fwd(u_int
, Channel
*, Buffer
*, Buffer
*);
171 static int process_mux_stop_listening(u_int
, Channel
*, Buffer
*, Buffer
*);
173 static const struct {
175 int (*handler
)(u_int
, Channel
*, Buffer
*, Buffer
*);
176 } mux_master_handlers
[] = {
177 { MUX_MSG_HELLO
, process_mux_master_hello
},
178 { MUX_C_NEW_SESSION
, process_mux_new_session
},
179 { MUX_C_ALIVE_CHECK
, process_mux_alive_check
},
180 { MUX_C_TERMINATE
, process_mux_terminate
},
181 { MUX_C_OPEN_FWD
, process_mux_open_fwd
},
182 { MUX_C_CLOSE_FWD
, process_mux_close_fwd
},
183 { MUX_C_NEW_STDIO_FWD
, process_mux_stdio_fwd
},
184 { MUX_C_STOP_LISTENING
, process_mux_stop_listening
},
188 /* Cleanup callback fired on closure of mux slave _session_ channel */
191 mux_master_session_cleanup_cb(int cid
, void *unused
)
193 Channel
*cc
, *c
= channel_by_id(cid
);
195 debug3("%s: entering for channel %d", __func__
, cid
);
197 fatal("%s: channel_by_id(%i) == NULL", __func__
, cid
);
198 if (c
->ctl_chan
!= -1) {
199 if ((cc
= channel_by_id(c
->ctl_chan
)) == NULL
)
200 fatal("%s: channel %d missing control channel %d",
201 __func__
, c
->self
, c
->ctl_chan
);
204 chan_rcvd_oclose(cc
);
206 channel_cancel_cleanup(c
->self
);
209 /* Cleanup callback fired on closure of mux slave _control_ channel */
212 mux_master_control_cleanup_cb(int cid
, void *unused
)
214 Channel
*sc
, *c
= channel_by_id(cid
);
216 debug3("%s: entering for channel %d", __func__
, cid
);
218 fatal("%s: channel_by_id(%i) == NULL", __func__
, cid
);
219 if (c
->remote_id
!= -1) {
220 if ((sc
= channel_by_id(c
->remote_id
)) == NULL
)
221 fatal("%s: channel %d missing session channel %d",
222 __func__
, c
->self
, c
->remote_id
);
225 if (sc
->type
!= SSH_CHANNEL_OPEN
&&
226 sc
->type
!= SSH_CHANNEL_OPENING
) {
227 debug2("%s: channel %d: not open", __func__
, sc
->self
);
230 if (sc
->istate
== CHAN_INPUT_OPEN
)
231 chan_read_failed(sc
);
232 if (sc
->ostate
== CHAN_OUTPUT_OPEN
)
233 chan_write_failed(sc
);
236 channel_cancel_cleanup(c
->self
);
239 /* Check mux client environment variables before passing them to mux master. */
241 env_permitted(char *env
)
244 char name
[1024], *cp
;
246 if ((cp
= strchr(env
, '=')) == NULL
|| cp
== env
)
248 ret
= snprintf(name
, sizeof(name
), "%.*s", (int)(cp
- env
), env
);
249 if (ret
<= 0 || (size_t)ret
>= sizeof(name
)) {
250 error("env_permitted: name '%.100s...' too long", env
);
254 for (i
= 0; i
< options
.num_send_env
; i
++)
255 if (match_pattern(name
, options
.send_env
[i
]))
261 /* Mux master protocol message handlers */
264 process_mux_master_hello(u_int rid
, Channel
*c
, Buffer
*m
, Buffer
*r
)
267 struct mux_master_state
*state
= (struct mux_master_state
*)c
->mux_ctx
;
270 fatal("%s: channel %d: c->mux_ctx == NULL", __func__
, c
->self
);
271 if (state
->hello_rcvd
) {
272 error("%s: HELLO received twice", __func__
);
275 if (buffer_get_int_ret(&ver
, m
) != 0) {
277 error("%s: malformed message", __func__
);
280 if (ver
!= SSHMUX_VER
) {
281 error("Unsupported multiplexing protocol version %d "
282 "(expected %d)", ver
, SSHMUX_VER
);
285 debug2("%s: channel %d slave version %u", __func__
, c
->self
, ver
);
287 /* No extensions are presently defined */
288 while (buffer_len(m
) > 0) {
289 char *name
= buffer_get_string_ret(m
, NULL
);
290 char *value
= buffer_get_string_ret(m
, NULL
);
292 if (name
== NULL
|| value
== NULL
) {
297 debug2("Unrecognised slave extension \"%s\"", name
);
301 state
->hello_rcvd
= 1;
306 process_mux_new_session(u_int rid
, Channel
*c
, Buffer
*m
, Buffer
*r
)
309 struct mux_session_confirm_ctx
*cctx
;
310 char *reserved
, *cmd
, *cp
;
311 u_int i
, j
, len
, env_len
, escape_char
, window
, packetmax
;
314 /* Reply for SSHMUX_COMMAND_OPEN */
315 cctx
= xcalloc(1, sizeof(*cctx
));
318 cmd
= reserved
= NULL
;
321 if ((reserved
= buffer_get_string_ret(m
, NULL
)) == NULL
||
322 buffer_get_int_ret(&cctx
->want_tty
, m
) != 0 ||
323 buffer_get_int_ret(&cctx
->want_x_fwd
, m
) != 0 ||
324 buffer_get_int_ret(&cctx
->want_agent_fwd
, m
) != 0 ||
325 buffer_get_int_ret(&cctx
->want_subsys
, m
) != 0 ||
326 buffer_get_int_ret(&escape_char
, m
) != 0 ||
327 (cctx
->term
= buffer_get_string_ret(m
, &len
)) == NULL
||
328 (cmd
= buffer_get_string_ret(m
, &len
)) == NULL
) {
332 for (j
= 0; j
< env_len
; j
++)
337 error("%s: malformed message", __func__
);
343 while (buffer_len(m
) > 0) {
344 #define MUX_MAX_ENV_VARS 4096
345 if ((cp
= buffer_get_string_ret(m
, &len
)) == NULL
)
347 if (!env_permitted(cp
)) {
351 cctx
->env
= xreallocarray(cctx
->env
, env_len
+ 2,
353 cctx
->env
[env_len
++] = cp
;
354 cctx
->env
[env_len
] = NULL
;
355 if (env_len
> MUX_MAX_ENV_VARS
) {
356 error(">%d environment variables received, ignoring "
357 "additional", MUX_MAX_ENV_VARS
);
362 debug2("%s: channel %d: request tty %d, X %d, agent %d, subsys %d, "
363 "term \"%s\", cmd \"%s\", env %u", __func__
, c
->self
,
364 cctx
->want_tty
, cctx
->want_x_fwd
, cctx
->want_agent_fwd
,
365 cctx
->want_subsys
, cctx
->term
, cmd
, env_len
);
367 buffer_init(&cctx
->cmd
);
368 buffer_append(&cctx
->cmd
, cmd
, strlen(cmd
));
372 /* Gather fds from client */
373 for(i
= 0; i
< 3; i
++) {
374 if ((new_fd
[i
] = mm_receive_fd(c
->sock
)) == -1) {
375 error("%s: failed to receive fd %d from slave",
377 for (j
= 0; j
< i
; j
++)
379 for (j
= 0; j
< env_len
; j
++)
383 buffer_free(&cctx
->cmd
);
387 buffer_put_int(r
, MUX_S_FAILURE
);
388 buffer_put_int(r
, rid
);
389 buffer_put_cstring(r
,
390 "did not receive file descriptors");
395 debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__
,
396 new_fd
[0], new_fd
[1], new_fd
[2]);
398 /* XXX support multiple child sessions in future */
399 if (c
->remote_id
!= -1) {
400 debug2("%s: session already open", __func__
);
402 buffer_put_int(r
, MUX_S_FAILURE
);
403 buffer_put_int(r
, rid
);
404 buffer_put_cstring(r
, "Multiple sessions not supported");
411 for (i
= 0; i
< env_len
; i
++)
415 buffer_free(&cctx
->cmd
);
420 if (options
.control_master
== SSHCTL_MASTER_ASK
||
421 options
.control_master
== SSHCTL_MASTER_AUTO_ASK
) {
422 if (!ask_permission("Allow shared connection to %s? ", host
)) {
423 debug2("%s: session refused by user", __func__
);
425 buffer_put_int(r
, MUX_S_PERMISSION_DENIED
);
426 buffer_put_int(r
, rid
);
427 buffer_put_cstring(r
, "Permission denied");
432 /* Try to pick up ttymodes from client before it goes raw */
433 if (cctx
->want_tty
&& tcgetattr(new_fd
[0], &cctx
->tio
) == -1)
434 error("%s: tcgetattr: %s", __func__
, strerror(errno
));
436 /* enable nonblocking unless tty */
437 if (!isatty(new_fd
[0]))
438 set_nonblock(new_fd
[0]);
439 if (!isatty(new_fd
[1]))
440 set_nonblock(new_fd
[1]);
441 if (!isatty(new_fd
[2]))
442 set_nonblock(new_fd
[2]);
444 window
= CHAN_SES_WINDOW_DEFAULT
;
445 packetmax
= CHAN_SES_PACKET_DEFAULT
;
446 if (cctx
->want_tty
) {
451 nc
= channel_new("session", SSH_CHANNEL_OPENING
,
452 new_fd
[0], new_fd
[1], new_fd
[2], window
, packetmax
,
453 CHAN_EXTENDED_WRITE
, "client-session", /*nonblock*/0);
455 nc
->ctl_chan
= c
->self
; /* link session -> control channel */
456 c
->remote_id
= nc
->self
; /* link control -> session channel */
458 if (cctx
->want_tty
&& escape_char
!= 0xffffffff) {
459 channel_register_filter(nc
->self
,
460 client_simple_escape_filter
, NULL
,
461 client_filter_cleanup
,
462 client_new_escape_filter_ctx((int)escape_char
));
465 debug2("%s: channel_new: %d linked to control channel %d",
466 __func__
, nc
->self
, nc
->ctl_chan
);
468 channel_send_open(nc
->self
);
469 channel_register_open_confirm(nc
->self
, mux_session_confirm
, cctx
);
470 c
->mux_pause
= 1; /* stop handling messages until open_confirm done */
471 channel_register_cleanup(nc
->self
, mux_master_session_cleanup_cb
, 1);
473 /* reply is deferred, sent by mux_session_confirm */
478 process_mux_alive_check(u_int rid
, Channel
*c
, Buffer
*m
, Buffer
*r
)
480 debug2("%s: channel %d: alive check", __func__
, c
->self
);
483 buffer_put_int(r
, MUX_S_ALIVE
);
484 buffer_put_int(r
, rid
);
485 buffer_put_int(r
, (u_int
)getpid());
491 process_mux_terminate(u_int rid
, Channel
*c
, Buffer
*m
, Buffer
*r
)
493 debug2("%s: channel %d: terminate request", __func__
, c
->self
);
495 if (options
.control_master
== SSHCTL_MASTER_ASK
||
496 options
.control_master
== SSHCTL_MASTER_AUTO_ASK
) {
497 if (!ask_permission("Terminate shared connection to %s? ",
499 debug2("%s: termination refused by user", __func__
);
500 buffer_put_int(r
, MUX_S_PERMISSION_DENIED
);
501 buffer_put_int(r
, rid
);
502 buffer_put_cstring(r
, "Permission denied");
508 buffer_put_int(r
, MUX_S_OK
);
509 buffer_put_int(r
, rid
);
510 /* XXX exit happens too soon - message never makes it to client */
515 format_forward(u_int ftype
, struct Forward
*fwd
)
521 xasprintf(&ret
, "local forward %.200s:%d -> %.200s:%d",
522 (fwd
->listen_path
!= NULL
) ? fwd
->listen_path
:
523 (fwd
->listen_host
== NULL
) ?
524 (options
.fwd_opts
.gateway_ports
? "*" : "LOCALHOST") :
525 fwd
->listen_host
, fwd
->listen_port
,
526 (fwd
->connect_path
!= NULL
) ? fwd
->connect_path
:
527 fwd
->connect_host
, fwd
->connect_port
);
529 case MUX_FWD_DYNAMIC
:
530 xasprintf(&ret
, "dynamic forward %.200s:%d -> *",
531 (fwd
->listen_host
== NULL
) ?
532 (options
.fwd_opts
.gateway_ports
? "*" : "LOCALHOST") :
533 fwd
->listen_host
, fwd
->listen_port
);
536 xasprintf(&ret
, "remote forward %.200s:%d -> %.200s:%d",
537 (fwd
->listen_path
!= NULL
) ? fwd
->listen_path
:
538 (fwd
->listen_host
== NULL
) ?
539 "LOCALHOST" : fwd
->listen_host
,
541 (fwd
->connect_path
!= NULL
) ? fwd
->connect_path
:
542 fwd
->connect_host
, fwd
->connect_port
);
545 fatal("%s: unknown forward type %u", __func__
, ftype
);
551 compare_host(const char *a
, const char *b
)
553 if (a
== NULL
&& b
== NULL
)
555 if (a
== NULL
|| b
== NULL
)
557 return strcmp(a
, b
) == 0;
561 compare_forward(struct Forward
*a
, struct Forward
*b
)
563 if (!compare_host(a
->listen_host
, b
->listen_host
))
565 if (!compare_host(a
->listen_path
, b
->listen_path
))
567 if (a
->listen_port
!= b
->listen_port
)
569 if (!compare_host(a
->connect_host
, b
->connect_host
))
571 if (!compare_host(a
->connect_path
, b
->connect_path
))
573 if (a
->connect_port
!= b
->connect_port
)
580 mux_confirm_remote_forward(int type
, u_int32_t seq
, void *ctxt
)
582 struct mux_channel_confirm_ctx
*fctx
= ctxt
;
583 char *failmsg
= NULL
;
584 struct Forward
*rfwd
;
588 if ((c
= channel_by_id(fctx
->cid
)) == NULL
) {
589 /* no channel for reply */
590 error("%s: unknown channel", __func__
);
594 if (fctx
->fid
>= options
.num_remote_forwards
||
595 (options
.remote_forwards
[fctx
->fid
].connect_path
== NULL
&&
596 options
.remote_forwards
[fctx
->fid
].connect_host
== NULL
)) {
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 debug("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
);
631 debug2("%s: clearing registered forwarding for listen %d, "
632 "connect %s:%d", __func__
, rfwd
->listen_port
,
633 rfwd
->connect_path
? rfwd
->connect_path
:
634 rfwd
->connect_host
, rfwd
->connect_port
);
636 free(rfwd
->listen_host
);
637 free(rfwd
->listen_path
);
638 free(rfwd
->connect_host
);
639 free(rfwd
->connect_path
);
640 memset(rfwd
, 0, sizeof(*rfwd
));
643 error("%s: %s", __func__
, failmsg
);
644 buffer_put_int(&out
, MUX_S_FAILURE
);
645 buffer_put_int(&out
, fctx
->rid
);
646 buffer_put_cstring(&out
, failmsg
);
649 buffer_put_string(&c
->output
, buffer_ptr(&out
), buffer_len(&out
));
651 if (c
->mux_pause
<= 0)
652 fatal("%s: mux_pause %d", __func__
, c
->mux_pause
);
653 c
->mux_pause
= 0; /* start processing messages again */
657 process_mux_open_fwd(u_int rid
, Channel
*c
, Buffer
*m
, Buffer
*r
)
660 char *fwd_desc
= NULL
;
661 char *listen_addr
, *connect_addr
;
664 int i
, ret
= 0, freefwd
= 1;
666 memset(&fwd
, 0, sizeof(fwd
));
668 /* XXX - lport/cport check redundant */
669 if (buffer_get_int_ret(&ftype
, m
) != 0 ||
670 (listen_addr
= buffer_get_string_ret(m
, NULL
)) == NULL
||
671 buffer_get_int_ret(&lport
, m
) != 0 ||
672 (connect_addr
= buffer_get_string_ret(m
, NULL
)) == NULL
||
673 buffer_get_int_ret(&cport
, m
) != 0 ||
674 (lport
!= (u_int
)PORT_STREAMLOCAL
&& lport
> 65535) ||
675 (cport
!= (u_int
)PORT_STREAMLOCAL
&& cport
> 65535)) {
676 error("%s: malformed message", __func__
);
680 if (*listen_addr
== '\0') {
684 if (*connect_addr
== '\0') {
689 memset(&fwd
, 0, sizeof(fwd
));
690 fwd
.listen_port
= lport
;
691 if (fwd
.listen_port
== PORT_STREAMLOCAL
)
692 fwd
.listen_path
= listen_addr
;
694 fwd
.listen_host
= listen_addr
;
695 fwd
.connect_port
= cport
;
696 if (fwd
.connect_port
== PORT_STREAMLOCAL
)
697 fwd
.connect_path
= connect_addr
;
699 fwd
.connect_host
= connect_addr
;
701 debug2("%s: channel %d: request %s", __func__
, c
->self
,
702 (fwd_desc
= format_forward(ftype
, &fwd
)));
704 if (ftype
!= MUX_FWD_LOCAL
&& ftype
!= MUX_FWD_REMOTE
&&
705 ftype
!= MUX_FWD_DYNAMIC
) {
706 logit("%s: invalid forwarding type %u", __func__
, ftype
);
710 buffer_put_int(r
, MUX_S_FAILURE
);
711 buffer_put_int(r
, rid
);
712 buffer_put_cstring(r
, "Invalid forwarding request");
715 if (ftype
== MUX_FWD_DYNAMIC
&& fwd
.listen_path
) {
716 logit("%s: streamlocal and dynamic forwards "
717 "are mutually exclusive", __func__
);
720 if (fwd
.listen_port
!= PORT_STREAMLOCAL
&& fwd
.listen_port
>= 65536) {
721 logit("%s: invalid listen port %u", __func__
,
725 if ((fwd
.connect_port
!= PORT_STREAMLOCAL
&& fwd
.connect_port
>= 65536)
726 || (ftype
!= MUX_FWD_DYNAMIC
&& ftype
!= MUX_FWD_REMOTE
&& fwd
.connect_port
== 0)) {
727 logit("%s: invalid connect port %u", __func__
,
731 if (ftype
!= MUX_FWD_DYNAMIC
&& fwd
.connect_host
== NULL
&& fwd
.connect_path
== NULL
) {
732 logit("%s: missing connect host", __func__
);
736 /* Skip forwards that have already been requested */
739 case MUX_FWD_DYNAMIC
:
740 for (i
= 0; i
< options
.num_local_forwards
; i
++) {
741 if (compare_forward(&fwd
,
742 options
.local_forwards
+ i
)) {
744 debug2("%s: found existing forwarding",
746 buffer_put_int(r
, MUX_S_OK
);
747 buffer_put_int(r
, rid
);
753 for (i
= 0; i
< options
.num_remote_forwards
; i
++) {
754 if (compare_forward(&fwd
,
755 options
.remote_forwards
+ i
)) {
756 if (fwd
.listen_port
!= 0)
758 debug2("%s: found allocated port",
760 buffer_put_int(r
, MUX_S_REMOTE_PORT
);
761 buffer_put_int(r
, rid
);
763 options
.remote_forwards
[i
].allocated_port
);
770 if (options
.control_master
== SSHCTL_MASTER_ASK
||
771 options
.control_master
== SSHCTL_MASTER_AUTO_ASK
) {
772 if (!ask_permission("Open %s on %s?", fwd_desc
, host
)) {
773 debug2("%s: forwarding refused by user", __func__
);
774 buffer_put_int(r
, MUX_S_PERMISSION_DENIED
);
775 buffer_put_int(r
, rid
);
776 buffer_put_cstring(r
, "Permission denied");
781 if (ftype
== MUX_FWD_LOCAL
|| ftype
== MUX_FWD_DYNAMIC
) {
782 if (!channel_setup_local_fwd_listener(&fwd
,
783 &options
.fwd_opts
)) {
785 logit("slave-requested %s failed", fwd_desc
);
786 buffer_put_int(r
, MUX_S_FAILURE
);
787 buffer_put_int(r
, rid
);
788 buffer_put_cstring(r
, "Port forwarding failed");
791 add_local_forward(&options
, &fwd
);
794 struct mux_channel_confirm_ctx
*fctx
;
796 fwd
.handle
= channel_request_remote_forwarding(&fwd
);
799 add_remote_forward(&options
, &fwd
);
800 fctx
= xcalloc(1, sizeof(*fctx
));
803 fctx
->fid
= options
.num_remote_forwards
- 1;
804 client_register_global_confirm(mux_confirm_remote_forward
,
807 c
->mux_pause
= 1; /* wait for mux_confirm_remote_forward */
808 /* delayed reply in mux_confirm_remote_forward */
811 buffer_put_int(r
, MUX_S_OK
);
812 buffer_put_int(r
, rid
);
816 free(fwd
.listen_host
);
817 free(fwd
.listen_path
);
818 free(fwd
.connect_host
);
819 free(fwd
.connect_path
);
825 process_mux_close_fwd(u_int rid
, Channel
*c
, Buffer
*m
, Buffer
*r
)
827 struct Forward fwd
, *found_fwd
;
828 char *fwd_desc
= NULL
;
829 const char *error_reason
= NULL
;
830 char *listen_addr
= NULL
, *connect_addr
= NULL
;
835 memset(&fwd
, 0, sizeof(fwd
));
837 if (buffer_get_int_ret(&ftype
, m
) != 0 ||
838 (listen_addr
= buffer_get_string_ret(m
, NULL
)) == NULL
||
839 buffer_get_int_ret(&lport
, m
) != 0 ||
840 (connect_addr
= buffer_get_string_ret(m
, NULL
)) == NULL
||
841 buffer_get_int_ret(&cport
, m
) != 0 ||
842 (lport
!= (u_int
)PORT_STREAMLOCAL
&& lport
> 65535) ||
843 (cport
!= (u_int
)PORT_STREAMLOCAL
&& cport
> 65535)) {
844 error("%s: malformed message", __func__
);
849 if (*listen_addr
== '\0') {
853 if (*connect_addr
== '\0') {
858 memset(&fwd
, 0, sizeof(fwd
));
859 fwd
.listen_port
= lport
;
860 if (fwd
.listen_port
== PORT_STREAMLOCAL
)
861 fwd
.listen_path
= listen_addr
;
863 fwd
.listen_host
= listen_addr
;
864 fwd
.connect_port
= cport
;
865 if (fwd
.connect_port
== PORT_STREAMLOCAL
)
866 fwd
.connect_path
= connect_addr
;
868 fwd
.connect_host
= connect_addr
;
870 debug2("%s: channel %d: request cancel %s", __func__
, c
->self
,
871 (fwd_desc
= format_forward(ftype
, &fwd
)));
873 /* make sure this has been requested */
877 case MUX_FWD_DYNAMIC
:
878 for (i
= 0; i
< options
.num_local_forwards
; i
++) {
879 if (compare_forward(&fwd
,
880 options
.local_forwards
+ i
)) {
881 found_fwd
= options
.local_forwards
+ i
;
887 for (i
= 0; i
< options
.num_remote_forwards
; i
++) {
888 if (compare_forward(&fwd
,
889 options
.remote_forwards
+ i
)) {
890 found_fwd
= options
.remote_forwards
+ i
;
897 if (found_fwd
== NULL
)
898 error_reason
= "port not forwarded";
899 else if (ftype
== MUX_FWD_REMOTE
) {
901 * This shouldn't fail unless we confused the host/port
902 * between options.remote_forwards and permitted_opens.
903 * However, for dynamic allocated listen ports we need
904 * to use the actual listen port.
906 if (channel_request_rforward_cancel(found_fwd
) == -1)
907 error_reason
= "port not in permitted opens";
908 } else { /* local and dynamic forwards */
910 if (channel_cancel_lport_listener(&fwd
, fwd
.connect_port
,
911 &options
.fwd_opts
) == -1)
912 error_reason
= "port not found";
915 if (error_reason
== NULL
) {
916 buffer_put_int(r
, MUX_S_OK
);
917 buffer_put_int(r
, rid
);
919 free(found_fwd
->listen_host
);
920 free(found_fwd
->listen_path
);
921 free(found_fwd
->connect_host
);
922 free(found_fwd
->connect_path
);
923 found_fwd
->listen_host
= found_fwd
->connect_host
= NULL
;
924 found_fwd
->listen_path
= found_fwd
->connect_path
= NULL
;
925 found_fwd
->listen_port
= found_fwd
->connect_port
= 0;
927 buffer_put_int(r
, MUX_S_FAILURE
);
928 buffer_put_int(r
, rid
);
929 buffer_put_cstring(r
, error_reason
);
940 process_mux_stdio_fwd(u_int rid
, Channel
*c
, Buffer
*m
, Buffer
*r
)
943 char *reserved
, *chost
;
946 struct mux_stdio_confirm_ctx
*cctx
;
948 chost
= reserved
= NULL
;
949 if ((reserved
= buffer_get_string_ret(m
, NULL
)) == NULL
||
950 (chost
= buffer_get_string_ret(m
, NULL
)) == NULL
||
951 buffer_get_int_ret(&cport
, m
) != 0) {
954 error("%s: malformed message", __func__
);
959 debug2("%s: channel %d: request stdio fwd to %s:%u",
960 __func__
, c
->self
, chost
, cport
);
962 /* Gather fds from client */
963 for(i
= 0; i
< 2; i
++) {
964 if ((new_fd
[i
] = mm_receive_fd(c
->sock
)) == -1) {
965 error("%s: failed to receive fd %d from slave",
967 for (j
= 0; j
< i
; j
++)
972 buffer_put_int(r
, MUX_S_FAILURE
);
973 buffer_put_int(r
, rid
);
974 buffer_put_cstring(r
,
975 "did not receive file descriptors");
980 debug3("%s: got fds stdin %d, stdout %d", __func__
,
981 new_fd
[0], new_fd
[1]);
983 /* XXX support multiple child sessions in future */
984 if (c
->remote_id
!= -1) {
985 debug2("%s: session already open", __func__
);
987 buffer_put_int(r
, MUX_S_FAILURE
);
988 buffer_put_int(r
, rid
);
989 buffer_put_cstring(r
, "Multiple sessions not supported");
997 if (options
.control_master
== SSHCTL_MASTER_ASK
||
998 options
.control_master
== SSHCTL_MASTER_AUTO_ASK
) {
999 if (!ask_permission("Allow forward to %s:%u? ",
1001 debug2("%s: stdio fwd refused by user", __func__
);
1003 buffer_put_int(r
, MUX_S_PERMISSION_DENIED
);
1004 buffer_put_int(r
, rid
);
1005 buffer_put_cstring(r
, "Permission denied");
1010 /* enable nonblocking unless tty */
1011 if (!isatty(new_fd
[0]))
1012 set_nonblock(new_fd
[0]);
1013 if (!isatty(new_fd
[1]))
1014 set_nonblock(new_fd
[1]);
1016 nc
= channel_connect_stdio_fwd(chost
, cport
, new_fd
[0], new_fd
[1]);
1018 nc
->ctl_chan
= c
->self
; /* link session -> control channel */
1019 c
->remote_id
= nc
->self
; /* link control -> session channel */
1021 debug2("%s: channel_new: %d linked to control channel %d",
1022 __func__
, nc
->self
, nc
->ctl_chan
);
1024 channel_register_cleanup(nc
->self
, mux_master_session_cleanup_cb
, 1);
1026 cctx
= xcalloc(1, sizeof(*cctx
));
1028 channel_register_open_confirm(nc
->self
, mux_stdio_confirm
, cctx
);
1029 c
->mux_pause
= 1; /* stop handling messages until open_confirm done */
1031 /* reply is deferred, sent by mux_session_confirm */
1035 /* Callback on open confirmation in mux master for a mux stdio fwd session. */
1037 mux_stdio_confirm(int id
, int success
, void *arg
)
1039 struct mux_stdio_confirm_ctx
*cctx
= arg
;
1044 fatal("%s: cctx == NULL", __func__
);
1045 if ((c
= channel_by_id(id
)) == NULL
)
1046 fatal("%s: no channel for id %d", __func__
, id
);
1047 if ((cc
= channel_by_id(c
->ctl_chan
)) == NULL
)
1048 fatal("%s: channel %d lacks control channel %d", __func__
,
1052 debug3("%s: sending failure reply", __func__
);
1054 buffer_init(&reply
);
1055 buffer_put_int(&reply
, MUX_S_FAILURE
);
1056 buffer_put_int(&reply
, cctx
->rid
);
1057 buffer_put_cstring(&reply
, "Session open refused by peer");
1061 debug3("%s: sending success reply", __func__
);
1063 buffer_init(&reply
);
1064 buffer_put_int(&reply
, MUX_S_SESSION_OPENED
);
1065 buffer_put_int(&reply
, cctx
->rid
);
1066 buffer_put_int(&reply
, c
->self
);
1070 buffer_put_string(&cc
->output
, buffer_ptr(&reply
), buffer_len(&reply
));
1071 buffer_free(&reply
);
1073 if (cc
->mux_pause
<= 0)
1074 fatal("%s: mux_pause %d", __func__
, cc
->mux_pause
);
1075 cc
->mux_pause
= 0; /* start processing messages again */
1076 c
->open_confirm_ctx
= NULL
;
1081 process_mux_stop_listening(u_int rid
, Channel
*c
, Buffer
*m
, Buffer
*r
)
1083 debug("%s: channel %d: stop listening", __func__
, c
->self
);
1085 if (options
.control_master
== SSHCTL_MASTER_ASK
||
1086 options
.control_master
== SSHCTL_MASTER_AUTO_ASK
) {
1087 if (!ask_permission("Disable further multiplexing on shared "
1088 "connection to %s? ", host
)) {
1089 debug2("%s: stop listen refused by user", __func__
);
1090 buffer_put_int(r
, MUX_S_PERMISSION_DENIED
);
1091 buffer_put_int(r
, rid
);
1092 buffer_put_cstring(r
, "Permission denied");
1097 if (mux_listener_channel
!= NULL
) {
1098 channel_free(mux_listener_channel
);
1100 free(options
.control_path
);
1101 options
.control_path
= NULL
;
1102 mux_listener_channel
= NULL
;
1103 muxserver_sock
= -1;
1107 buffer_put_int(r
, MUX_S_OK
);
1108 buffer_put_int(r
, rid
);
1113 /* Channel callbacks fired on read/write from mux slave fd */
1115 mux_master_read_cb(Channel
*c
)
1117 struct mux_master_state
*state
= (struct mux_master_state
*)c
->mux_ctx
;
1120 u_int type
, rid
, have
, i
;
1124 if (c
->mux_ctx
== NULL
) {
1125 state
= xcalloc(1, sizeof(*state
));
1127 channel_register_cleanup(c
->self
,
1128 mux_master_control_cleanup_cb
, 0);
1132 buffer_put_int(&out
, MUX_MSG_HELLO
);
1133 buffer_put_int(&out
, SSHMUX_VER
);
1135 buffer_put_string(&c
->output
, buffer_ptr(&out
),
1138 debug3("%s: channel %d: hello sent", __func__
, c
->self
);
1145 /* Channel code ensures that we receive whole packets */
1146 if ((ptr
= buffer_get_string_ptr_ret(&c
->input
, &have
)) == NULL
) {
1148 error("%s: malformed message", __func__
);
1151 buffer_append(&in
, ptr
, have
);
1153 if (buffer_get_int_ret(&type
, &in
) != 0)
1155 debug3("%s: channel %d packet type 0x%08x len %u",
1156 __func__
, c
->self
, type
, buffer_len(&in
));
1158 if (type
== MUX_MSG_HELLO
)
1161 if (!state
->hello_rcvd
) {
1162 error("%s: expected MUX_MSG_HELLO(0x%08x), "
1163 "received 0x%08x", __func__
, MUX_MSG_HELLO
, type
);
1166 if (buffer_get_int_ret(&rid
, &in
) != 0)
1170 for (i
= 0; mux_master_handlers
[i
].handler
!= NULL
; i
++) {
1171 if (type
== mux_master_handlers
[i
].type
) {
1172 ret
= mux_master_handlers
[i
].handler(rid
, c
, &in
, &out
);
1176 if (mux_master_handlers
[i
].handler
== NULL
) {
1177 error("%s: unsupported mux message 0x%08x", __func__
, type
);
1178 buffer_put_int(&out
, MUX_S_FAILURE
);
1179 buffer_put_int(&out
, rid
);
1180 buffer_put_cstring(&out
, "unsupported request");
1183 /* Enqueue reply packet */
1184 if (buffer_len(&out
) != 0) {
1185 buffer_put_string(&c
->output
, buffer_ptr(&out
),
1195 mux_exit_message(Channel
*c
, int exitval
)
1200 debug3("%s: channel %d: exit message, exitval %d", __func__
, c
->self
,
1203 if ((mux_chan
= channel_by_id(c
->ctl_chan
)) == NULL
)
1204 fatal("%s: channel %d missing mux channel %d",
1205 __func__
, c
->self
, c
->ctl_chan
);
1207 /* Append exit message packet to control socket output queue */
1209 buffer_put_int(&m
, MUX_S_EXIT_MESSAGE
);
1210 buffer_put_int(&m
, c
->self
);
1211 buffer_put_int(&m
, exitval
);
1213 buffer_put_string(&mux_chan
->output
, buffer_ptr(&m
), buffer_len(&m
));
1218 mux_tty_alloc_failed(Channel
*c
)
1223 debug3("%s: channel %d: TTY alloc failed", __func__
, c
->self
);
1225 if ((mux_chan
= channel_by_id(c
->ctl_chan
)) == NULL
)
1226 fatal("%s: channel %d missing mux channel %d",
1227 __func__
, c
->self
, c
->ctl_chan
);
1229 /* Append exit message packet to control socket output queue */
1231 buffer_put_int(&m
, MUX_S_TTY_ALLOC_FAIL
);
1232 buffer_put_int(&m
, c
->self
);
1234 buffer_put_string(&mux_chan
->output
, buffer_ptr(&m
), buffer_len(&m
));
1238 /* Prepare a mux master to listen on a Unix domain socket. */
1240 muxserver_listen(void)
1243 char *orig_control_path
= options
.control_path
;
1248 if (options
.control_path
== NULL
||
1249 options
.control_master
== SSHCTL_MASTER_NO
)
1252 debug("setting up multiplex master socket");
1255 * Use a temporary path before listen so we can pseudo-atomically
1256 * establish the listening socket in its final location to avoid
1257 * other processes racing in between bind() and listen() and hitting
1258 * an unready socket.
1260 for (i
= 0; i
< sizeof(rbuf
) - 1; i
++) {
1261 r
= arc4random_uniform(26+26+10);
1262 rbuf
[i
] = (r
< 26) ? 'a' + r
:
1263 (r
< 26*2) ? 'A' + r
- 26 :
1266 rbuf
[sizeof(rbuf
) - 1] = '\0';
1267 options
.control_path
= NULL
;
1268 xasprintf(&options
.control_path
, "%s.%s", orig_control_path
, rbuf
);
1269 debug3("%s: temporary control path %s", __func__
, options
.control_path
);
1271 old_umask
= umask(0177);
1272 muxserver_sock
= unix_listener(options
.control_path
, 64, 0);
1275 if (muxserver_sock
< 0) {
1276 if (oerrno
== EINVAL
|| oerrno
== EADDRINUSE
) {
1277 error("ControlSocket %s already exists, "
1278 "disabling multiplexing", options
.control_path
);
1280 if (muxserver_sock
!= -1) {
1281 close(muxserver_sock
);
1282 muxserver_sock
= -1;
1284 free(orig_control_path
);
1285 free(options
.control_path
);
1286 options
.control_path
= NULL
;
1287 options
.control_master
= SSHCTL_MASTER_NO
;
1290 /* unix_listener() logs the error */
1295 /* Now atomically "move" the mux socket into position */
1296 if (link(options
.control_path
, orig_control_path
) != 0) {
1297 if (errno
!= EEXIST
) {
1298 fatal("%s: link mux listener %s => %s: %s", __func__
,
1299 options
.control_path
, orig_control_path
,
1302 error("ControlSocket %s already exists, disabling multiplexing",
1304 unlink(options
.control_path
);
1305 goto disable_mux_master
;
1307 unlink(options
.control_path
);
1308 free(options
.control_path
);
1309 options
.control_path
= orig_control_path
;
1311 set_nonblock(muxserver_sock
);
1313 mux_listener_channel
= channel_new("mux listener",
1314 SSH_CHANNEL_MUX_LISTENER
, muxserver_sock
, muxserver_sock
, -1,
1315 CHAN_TCP_WINDOW_DEFAULT
, CHAN_TCP_PACKET_DEFAULT
,
1316 0, options
.control_path
, 1);
1317 mux_listener_channel
->mux_rcb
= mux_master_read_cb
;
1318 debug3("%s: mux listener channel %d fd %d", __func__
,
1319 mux_listener_channel
->self
, mux_listener_channel
->sock
);
1322 /* Callback on open confirmation in mux master for a mux client session. */
1324 mux_session_confirm(int id
, int success
, void *arg
)
1326 struct mux_session_confirm_ctx
*cctx
= arg
;
1327 const char *display
;
1333 fatal("%s: cctx == NULL", __func__
);
1334 if ((c
= channel_by_id(id
)) == NULL
)
1335 fatal("%s: no channel for id %d", __func__
, id
);
1336 if ((cc
= channel_by_id(c
->ctl_chan
)) == NULL
)
1337 fatal("%s: channel %d lacks control channel %d", __func__
,
1341 debug3("%s: sending failure reply", __func__
);
1343 buffer_init(&reply
);
1344 buffer_put_int(&reply
, MUX_S_FAILURE
);
1345 buffer_put_int(&reply
, cctx
->rid
);
1346 buffer_put_cstring(&reply
, "Session open refused by peer");
1350 display
= getenv("DISPLAY");
1351 if (cctx
->want_x_fwd
&& options
.forward_x11
&& display
!= NULL
) {
1354 /* Get reasonable local authentication information. */
1355 if (client_x11_get_proto(display
, options
.xauth_location
,
1356 options
.forward_x11_trusted
, options
.forward_x11_timeout
,
1357 &proto
, &data
) == 0) {
1358 /* Request forwarding with authentication spoofing. */
1359 debug("Requesting X11 forwarding with authentication "
1361 x11_request_forwarding_with_spoofing(id
, display
, proto
,
1363 /* XXX exit_on_forward_failure */
1364 client_expect_confirm(id
, "X11 forwarding",
1369 if (cctx
->want_agent_fwd
&& options
.forward_agent
) {
1370 debug("Requesting authentication agent forwarding.");
1371 channel_request_start(id
, "auth-agent-req@openssh.com", 0);
1375 client_session2_setup(id
, cctx
->want_tty
, cctx
->want_subsys
,
1376 cctx
->term
, &cctx
->tio
, c
->rfd
, &cctx
->cmd
, cctx
->env
);
1378 debug3("%s: sending success reply", __func__
);
1380 buffer_init(&reply
);
1381 buffer_put_int(&reply
, MUX_S_SESSION_OPENED
);
1382 buffer_put_int(&reply
, cctx
->rid
);
1383 buffer_put_int(&reply
, c
->self
);
1387 buffer_put_string(&cc
->output
, buffer_ptr(&reply
), buffer_len(&reply
));
1388 buffer_free(&reply
);
1390 if (cc
->mux_pause
<= 0)
1391 fatal("%s: mux_pause %d", __func__
, cc
->mux_pause
);
1392 cc
->mux_pause
= 0; /* start processing messages again */
1393 c
->open_confirm_ctx
= NULL
;
1394 buffer_free(&cctx
->cmd
);
1396 if (cctx
->env
!= NULL
) {
1397 for (i
= 0; cctx
->env
[i
] != NULL
; i
++)
1404 /* ** Multiplexing client support */
1406 /* Exit signal handler */
1408 control_client_sighandler(int signo
)
1410 muxclient_terminate
= signo
;
1414 * Relay signal handler - used to pass some signals from mux client to
1418 control_client_sigrelay(int signo
)
1420 int save_errno
= errno
;
1422 if (muxserver_pid
> 1)
1423 kill(muxserver_pid
, signo
);
1429 mux_client_read(int fd
, Buffer
*b
, u_int need
)
1437 pfd
.events
= POLLIN
;
1438 p
= buffer_append_space(b
, need
);
1439 for (have
= 0; have
< need
; ) {
1440 if (muxclient_terminate
) {
1444 len
= read(fd
, p
+ have
, need
- have
);
1447 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1451 (void)poll(&pfd
, 1, -1);
1469 mux_client_write_packet(int fd
, Buffer
*m
)
1478 pfd
.events
= POLLOUT
;
1479 buffer_init(&queue
);
1480 buffer_put_string(&queue
, buffer_ptr(m
), buffer_len(m
));
1482 need
= buffer_len(&queue
);
1483 ptr
= buffer_ptr(&queue
);
1485 for (have
= 0; have
< need
; ) {
1486 if (muxclient_terminate
) {
1487 buffer_free(&queue
);
1491 len
= write(fd
, ptr
+ have
, need
- have
);
1494 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1498 (void)poll(&pfd
, 1, -1);
1504 buffer_free(&queue
);
1510 buffer_free(&queue
);
1516 buffer_free(&queue
);
1521 mux_client_read_packet(int fd
, Buffer
*m
)
1528 buffer_init(&queue
);
1529 if (mux_client_read(fd
, &queue
, 4) != 0) {
1530 if ((oerrno
= errno
) == EPIPE
)
1531 debug3("%s: read header failed: %s", __func__
,
1533 buffer_free(&queue
);
1537 need
= get_u32(buffer_ptr(&queue
));
1538 if (mux_client_read(fd
, &queue
, need
) != 0) {
1540 debug3("%s: read body failed: %s", __func__
, strerror(errno
));
1541 buffer_free(&queue
);
1545 ptr
= buffer_get_string_ptr(&queue
, &have
);
1546 buffer_append(m
, ptr
, have
);
1547 buffer_free(&queue
);
1552 mux_client_hello_exchange(int fd
)
1558 buffer_put_int(&m
, MUX_MSG_HELLO
);
1559 buffer_put_int(&m
, SSHMUX_VER
);
1562 if (mux_client_write_packet(fd
, &m
) != 0)
1563 fatal("%s: write packet: %s", __func__
, strerror(errno
));
1567 /* Read their HELLO */
1568 if (mux_client_read_packet(fd
, &m
) != 0) {
1573 type
= buffer_get_int(&m
);
1574 if (type
!= MUX_MSG_HELLO
)
1575 fatal("%s: expected HELLO (%u) received %u",
1576 __func__
, MUX_MSG_HELLO
, type
);
1577 ver
= buffer_get_int(&m
);
1578 if (ver
!= SSHMUX_VER
)
1579 fatal("Unsupported multiplexing protocol version %d "
1580 "(expected %d)", ver
, SSHMUX_VER
);
1581 debug2("%s: master version %u", __func__
, ver
);
1582 /* No extensions are presently defined */
1583 while (buffer_len(&m
) > 0) {
1584 char *name
= buffer_get_string(&m
, NULL
);
1585 char *value
= buffer_get_string(&m
, NULL
);
1587 debug2("Unrecognised master extension \"%s\"", name
);
1596 mux_client_request_alive(int fd
)
1600 u_int pid
, type
, rid
;
1602 debug3("%s: entering", __func__
);
1605 buffer_put_int(&m
, MUX_C_ALIVE_CHECK
);
1606 buffer_put_int(&m
, muxclient_request_id
);
1608 if (mux_client_write_packet(fd
, &m
) != 0)
1609 fatal("%s: write packet: %s", __func__
, strerror(errno
));
1613 /* Read their reply */
1614 if (mux_client_read_packet(fd
, &m
) != 0) {
1619 type
= buffer_get_int(&m
);
1620 if (type
!= MUX_S_ALIVE
) {
1621 e
= buffer_get_string(&m
, NULL
);
1622 fatal("%s: master returned error: %s", __func__
, e
);
1625 if ((rid
= buffer_get_int(&m
)) != muxclient_request_id
)
1626 fatal("%s: out of sequence reply: my id %u theirs %u",
1627 __func__
, muxclient_request_id
, rid
);
1628 pid
= buffer_get_int(&m
);
1631 debug3("%s: done pid = %u", __func__
, pid
);
1633 muxclient_request_id
++;
1639 mux_client_request_terminate(int fd
)
1645 debug3("%s: entering", __func__
);
1648 buffer_put_int(&m
, MUX_C_TERMINATE
);
1649 buffer_put_int(&m
, muxclient_request_id
);
1651 if (mux_client_write_packet(fd
, &m
) != 0)
1652 fatal("%s: write packet: %s", __func__
, strerror(errno
));
1656 /* Read their reply */
1657 if (mux_client_read_packet(fd
, &m
) != 0) {
1658 /* Remote end exited already */
1659 if (errno
== EPIPE
) {
1663 fatal("%s: read from master failed: %s",
1664 __func__
, strerror(errno
));
1667 type
= buffer_get_int(&m
);
1668 if ((rid
= buffer_get_int(&m
)) != muxclient_request_id
)
1669 fatal("%s: out of sequence reply: my id %u theirs %u",
1670 __func__
, muxclient_request_id
, rid
);
1674 case MUX_S_PERMISSION_DENIED
:
1675 e
= buffer_get_string(&m
, NULL
);
1676 fatal("Master refused termination request: %s", e
);
1678 e
= buffer_get_string(&m
, NULL
);
1679 fatal("%s: termination request failed: %s", __func__
, e
);
1681 fatal("%s: unexpected response from master 0x%08x",
1685 muxclient_request_id
++;
1689 mux_client_forward(int fd
, int cancel_flag
, u_int ftype
, struct Forward
*fwd
)
1695 fwd_desc
= format_forward(ftype
, fwd
);
1696 debug("Requesting %s %s",
1697 cancel_flag
? "cancellation of" : "forwarding of", fwd_desc
);
1701 buffer_put_int(&m
, cancel_flag
? MUX_C_CLOSE_FWD
: MUX_C_OPEN_FWD
);
1702 buffer_put_int(&m
, muxclient_request_id
);
1703 buffer_put_int(&m
, ftype
);
1704 if (fwd
->listen_path
!= NULL
) {
1705 buffer_put_cstring(&m
, fwd
->listen_path
);
1707 buffer_put_cstring(&m
,
1708 fwd
->listen_host
== NULL
? "" :
1709 (*fwd
->listen_host
== '\0' ? "*" : fwd
->listen_host
));
1711 buffer_put_int(&m
, fwd
->listen_port
);
1712 if (fwd
->connect_path
!= NULL
) {
1713 buffer_put_cstring(&m
, fwd
->connect_path
);
1715 buffer_put_cstring(&m
,
1716 fwd
->connect_host
== NULL
? "" : fwd
->connect_host
);
1718 buffer_put_int(&m
, fwd
->connect_port
);
1720 if (mux_client_write_packet(fd
, &m
) != 0)
1721 fatal("%s: write packet: %s", __func__
, strerror(errno
));
1725 /* Read their reply */
1726 if (mux_client_read_packet(fd
, &m
) != 0) {
1731 type
= buffer_get_int(&m
);
1732 if ((rid
= buffer_get_int(&m
)) != muxclient_request_id
)
1733 fatal("%s: out of sequence reply: my id %u theirs %u",
1734 __func__
, muxclient_request_id
, rid
);
1738 case MUX_S_REMOTE_PORT
:
1740 fatal("%s: got MUX_S_REMOTE_PORT for cancel", __func__
);
1741 fwd
->allocated_port
= buffer_get_int(&m
);
1742 verbose("Allocated port %u for remote forward to %s:%d",
1743 fwd
->allocated_port
,
1744 fwd
->connect_host
? fwd
->connect_host
: "",
1746 if (muxclient_command
== SSHMUX_COMMAND_FORWARD
)
1747 fprintf(stdout
, "%i\n", fwd
->allocated_port
);
1749 case MUX_S_PERMISSION_DENIED
:
1750 e
= buffer_get_string(&m
, NULL
);
1752 error("Master refused forwarding request: %s", e
);
1755 e
= buffer_get_string(&m
, NULL
);
1757 error("%s: forwarding request failed: %s", __func__
, e
);
1760 fatal("%s: unexpected response from master 0x%08x",
1765 muxclient_request_id
++;
1770 mux_client_forwards(int fd
, int cancel_flag
)
1774 debug3("%s: %s forwardings: %d local, %d remote", __func__
,
1775 cancel_flag
? "cancel" : "request",
1776 options
.num_local_forwards
, options
.num_remote_forwards
);
1778 /* XXX ExitOnForwardingFailure */
1779 for (i
= 0; i
< options
.num_local_forwards
; i
++) {
1780 if (mux_client_forward(fd
, cancel_flag
,
1781 options
.local_forwards
[i
].connect_port
== 0 ?
1782 MUX_FWD_DYNAMIC
: MUX_FWD_LOCAL
,
1783 options
.local_forwards
+ i
) != 0)
1786 for (i
= 0; i
< options
.num_remote_forwards
; i
++) {
1787 if (mux_client_forward(fd
, cancel_flag
, MUX_FWD_REMOTE
,
1788 options
.remote_forwards
+ i
) != 0)
1795 mux_client_request_session(int fd
)
1799 u_int i
, rid
, sid
, esid
, exitval
, type
, exitval_seen
;
1800 extern char **environ
;
1801 int devnull
, rawmode
;
1803 debug3("%s: entering", __func__
);
1805 if ((muxserver_pid
= mux_client_request_alive(fd
)) == 0) {
1806 error("%s: master alive request failed", __func__
);
1810 signal(SIGPIPE
, SIG_IGN
);
1812 if (stdin_null_flag
) {
1813 if ((devnull
= open(_PATH_DEVNULL
, O_RDONLY
)) == -1)
1814 fatal("open(/dev/null): %s", strerror(errno
));
1815 if (dup2(devnull
, STDIN_FILENO
) == -1)
1816 fatal("dup2: %s", strerror(errno
));
1817 if (devnull
> STDERR_FILENO
)
1821 term
= getenv("TERM");
1824 buffer_put_int(&m
, MUX_C_NEW_SESSION
);
1825 buffer_put_int(&m
, muxclient_request_id
);
1826 buffer_put_cstring(&m
, ""); /* reserved */
1827 buffer_put_int(&m
, tty_flag
);
1828 buffer_put_int(&m
, options
.forward_x11
);
1829 buffer_put_int(&m
, options
.forward_agent
);
1830 buffer_put_int(&m
, subsystem_flag
);
1831 buffer_put_int(&m
, options
.escape_char
== SSH_ESCAPECHAR_NONE
?
1832 0xffffffff : (u_int
)options
.escape_char
);
1833 buffer_put_cstring(&m
, term
== NULL
? "" : term
);
1834 buffer_put_string(&m
, buffer_ptr(&command
), buffer_len(&command
));
1836 if (options
.num_send_env
> 0 && environ
!= NULL
) {
1837 /* Pass environment */
1838 for (i
= 0; environ
[i
] != NULL
; i
++) {
1839 if (env_permitted(environ
[i
])) {
1840 buffer_put_cstring(&m
, environ
[i
]);
1845 if (mux_client_write_packet(fd
, &m
) != 0)
1846 fatal("%s: write packet: %s", __func__
, strerror(errno
));
1848 /* Send the stdio file descriptors */
1849 if (mm_send_fd(fd
, STDIN_FILENO
) == -1 ||
1850 mm_send_fd(fd
, STDOUT_FILENO
) == -1 ||
1851 mm_send_fd(fd
, STDERR_FILENO
) == -1)
1852 fatal("%s: send fds failed", __func__
);
1854 debug3("%s: session request sent", __func__
);
1856 /* Read their reply */
1858 if (mux_client_read_packet(fd
, &m
) != 0) {
1859 error("%s: read from master failed: %s",
1860 __func__
, strerror(errno
));
1865 type
= buffer_get_int(&m
);
1866 if ((rid
= buffer_get_int(&m
)) != muxclient_request_id
)
1867 fatal("%s: out of sequence reply: my id %u theirs %u",
1868 __func__
, muxclient_request_id
, rid
);
1870 case MUX_S_SESSION_OPENED
:
1871 sid
= buffer_get_int(&m
);
1872 debug("%s: master session id: %u", __func__
, sid
);
1874 case MUX_S_PERMISSION_DENIED
:
1875 e
= buffer_get_string(&m
, NULL
);
1877 error("Master refused session request: %s", e
);
1880 e
= buffer_get_string(&m
, NULL
);
1882 error("%s: session request failed: %s", __func__
, e
);
1886 error("%s: unexpected response from master 0x%08x",
1890 muxclient_request_id
++;
1892 if (pledge("stdio proc tty", NULL
) == -1)
1893 fatal("%s pledge(): %s", __func__
, strerror(errno
));
1894 platform_pledge_mux();
1896 signal(SIGHUP
, control_client_sighandler
);
1897 signal(SIGINT
, control_client_sighandler
);
1898 signal(SIGTERM
, control_client_sighandler
);
1899 signal(SIGWINCH
, control_client_sigrelay
);
1903 enter_raw_mode(options
.request_tty
== REQUEST_TTY_FORCE
);
1906 * Stick around until the controlee closes the client_fd.
1907 * Before it does, it is expected to write an exit message.
1908 * This process must read the value and wait for the closure of
1909 * the client_fd; if this one closes early, the multiplex master will
1910 * terminate early too (possibly losing data).
1912 for (exitval
= 255, exitval_seen
= 0;;) {
1914 if (mux_client_read_packet(fd
, &m
) != 0)
1916 type
= buffer_get_int(&m
);
1918 case MUX_S_TTY_ALLOC_FAIL
:
1919 if ((esid
= buffer_get_int(&m
)) != sid
)
1920 fatal("%s: tty alloc fail on unknown session: "
1921 "my id %u theirs %u",
1922 __func__
, sid
, esid
);
1923 leave_raw_mode(options
.request_tty
==
1927 case MUX_S_EXIT_MESSAGE
:
1928 if ((esid
= buffer_get_int(&m
)) != sid
)
1929 fatal("%s: exit on unknown session: "
1930 "my id %u theirs %u",
1931 __func__
, sid
, esid
);
1933 fatal("%s: exitval sent twice", __func__
);
1934 exitval
= buffer_get_int(&m
);
1938 e
= buffer_get_string(&m
, NULL
);
1939 fatal("%s: master returned error: %s", __func__
, e
);
1945 leave_raw_mode(options
.request_tty
== REQUEST_TTY_FORCE
);
1947 if (muxclient_terminate
) {
1948 debug2("Exiting on signal %d", muxclient_terminate
);
1950 } else if (!exitval_seen
) {
1951 debug2("Control master terminated unexpectedly");
1954 debug2("Received exit status from master %d", exitval
);
1956 if (tty_flag
&& options
.log_level
!= SYSLOG_LEVEL_QUIET
)
1957 fprintf(stderr
, "Shared connection to %s closed.\r\n", host
);
1963 mux_client_request_stdio_fwd(int fd
)
1967 u_int type
, rid
, sid
;
1970 debug3("%s: entering", __func__
);
1972 if ((muxserver_pid
= mux_client_request_alive(fd
)) == 0) {
1973 error("%s: master alive request failed", __func__
);
1977 signal(SIGPIPE
, SIG_IGN
);
1979 if (stdin_null_flag
) {
1980 if ((devnull
= open(_PATH_DEVNULL
, O_RDONLY
)) == -1)
1981 fatal("open(/dev/null): %s", strerror(errno
));
1982 if (dup2(devnull
, STDIN_FILENO
) == -1)
1983 fatal("dup2: %s", strerror(errno
));
1984 if (devnull
> STDERR_FILENO
)
1989 buffer_put_int(&m
, MUX_C_NEW_STDIO_FWD
);
1990 buffer_put_int(&m
, muxclient_request_id
);
1991 buffer_put_cstring(&m
, ""); /* reserved */
1992 buffer_put_cstring(&m
, options
.stdio_forward_host
);
1993 buffer_put_int(&m
, options
.stdio_forward_port
);
1995 if (mux_client_write_packet(fd
, &m
) != 0)
1996 fatal("%s: write packet: %s", __func__
, strerror(errno
));
1998 /* Send the stdio file descriptors */
1999 if (mm_send_fd(fd
, STDIN_FILENO
) == -1 ||
2000 mm_send_fd(fd
, STDOUT_FILENO
) == -1)
2001 fatal("%s: send fds failed", __func__
);
2003 if (pledge("stdio proc tty", NULL
) == -1)
2004 fatal("%s pledge(): %s", __func__
, strerror(errno
));
2005 platform_pledge_mux();
2007 debug3("%s: stdio forward request sent", __func__
);
2009 /* Read their reply */
2012 if (mux_client_read_packet(fd
, &m
) != 0) {
2013 error("%s: read from master failed: %s",
2014 __func__
, strerror(errno
));
2019 type
= buffer_get_int(&m
);
2020 if ((rid
= buffer_get_int(&m
)) != muxclient_request_id
)
2021 fatal("%s: out of sequence reply: my id %u theirs %u",
2022 __func__
, muxclient_request_id
, rid
);
2024 case MUX_S_SESSION_OPENED
:
2025 sid
= buffer_get_int(&m
);
2026 debug("%s: master session id: %u", __func__
, sid
);
2028 case MUX_S_PERMISSION_DENIED
:
2029 e
= buffer_get_string(&m
, NULL
);
2031 fatal("Master refused stdio forwarding request: %s", e
);
2033 e
= buffer_get_string(&m
, NULL
);
2035 fatal("Stdio forwarding request failed: %s", e
);
2038 error("%s: unexpected response from master 0x%08x",
2042 muxclient_request_id
++;
2044 signal(SIGHUP
, control_client_sighandler
);
2045 signal(SIGINT
, control_client_sighandler
);
2046 signal(SIGTERM
, control_client_sighandler
);
2047 signal(SIGWINCH
, control_client_sigrelay
);
2050 * Stick around until the controlee closes the client_fd.
2053 if (mux_client_read_packet(fd
, &m
) != 0) {
2054 if (errno
== EPIPE
||
2055 (errno
== EINTR
&& muxclient_terminate
!= 0))
2057 fatal("%s: mux_client_read_packet: %s",
2058 __func__
, strerror(errno
));
2060 fatal("%s: master returned unexpected message %u", __func__
, type
);
2064 mux_client_request_stop_listening(int fd
)
2070 debug3("%s: entering", __func__
);
2073 buffer_put_int(&m
, MUX_C_STOP_LISTENING
);
2074 buffer_put_int(&m
, muxclient_request_id
);
2076 if (mux_client_write_packet(fd
, &m
) != 0)
2077 fatal("%s: write packet: %s", __func__
, strerror(errno
));
2081 /* Read their reply */
2082 if (mux_client_read_packet(fd
, &m
) != 0)
2083 fatal("%s: read from master failed: %s",
2084 __func__
, strerror(errno
));
2086 type
= buffer_get_int(&m
);
2087 if ((rid
= buffer_get_int(&m
)) != muxclient_request_id
)
2088 fatal("%s: out of sequence reply: my id %u theirs %u",
2089 __func__
, muxclient_request_id
, rid
);
2093 case MUX_S_PERMISSION_DENIED
:
2094 e
= buffer_get_string(&m
, NULL
);
2095 fatal("Master refused stop listening request: %s", e
);
2097 e
= buffer_get_string(&m
, NULL
);
2098 fatal("%s: stop listening request failed: %s", __func__
, e
);
2100 fatal("%s: unexpected response from master 0x%08x",
2104 muxclient_request_id
++;
2107 /* Multiplex client main loop. */
2109 muxclient(const char *path
)
2111 struct sockaddr_un addr
;
2116 if (muxclient_command
== 0) {
2117 if (options
.stdio_forward_host
!= NULL
)
2118 muxclient_command
= SSHMUX_COMMAND_STDIO_FWD
;
2120 muxclient_command
= SSHMUX_COMMAND_OPEN
;
2123 switch (options
.control_master
) {
2124 case SSHCTL_MASTER_AUTO
:
2125 case SSHCTL_MASTER_AUTO_ASK
:
2126 debug("auto-mux: Trying existing master");
2128 case SSHCTL_MASTER_NO
:
2134 memset(&addr
, '\0', sizeof(addr
));
2135 addr
.sun_family
= AF_UNIX
;
2136 sun_len
= offsetof(struct sockaddr_un
, sun_path
) +
2139 if (strlcpy(addr
.sun_path
, path
,
2140 sizeof(addr
.sun_path
)) >= sizeof(addr
.sun_path
))
2141 fatal("ControlPath too long");
2143 if ((sock
= socket(PF_UNIX
, SOCK_STREAM
, 0)) < 0)
2144 fatal("%s socket(): %s", __func__
, strerror(errno
));
2146 if (connect(sock
, (struct sockaddr
*)&addr
, sun_len
) == -1) {
2147 switch (muxclient_command
) {
2148 case SSHMUX_COMMAND_OPEN
:
2149 case SSHMUX_COMMAND_STDIO_FWD
:
2152 fatal("Control socket connect(%.100s): %s", path
,
2155 if (errno
== ECONNREFUSED
&&
2156 options
.control_master
!= SSHCTL_MASTER_NO
) {
2157 debug("Stale control socket %.100s, unlinking", path
);
2159 } else if (errno
== ENOENT
) {
2160 debug("Control socket \"%.100s\" does not exist", path
);
2162 error("Control socket connect(%.100s): %s", path
,
2170 if (mux_client_hello_exchange(sock
) != 0) {
2171 error("%s: master hello exchange failed", __func__
);
2176 switch (muxclient_command
) {
2177 case SSHMUX_COMMAND_ALIVE_CHECK
:
2178 if ((pid
= mux_client_request_alive(sock
)) == 0)
2179 fatal("%s: master alive check failed", __func__
);
2180 fprintf(stderr
, "Master running (pid=%u)\r\n", pid
);
2182 case SSHMUX_COMMAND_TERMINATE
:
2183 mux_client_request_terminate(sock
);
2184 fprintf(stderr
, "Exit request sent.\r\n");
2186 case SSHMUX_COMMAND_FORWARD
:
2187 if (mux_client_forwards(sock
, 0) != 0)
2188 fatal("%s: master forward request failed", __func__
);
2190 case SSHMUX_COMMAND_OPEN
:
2191 if (mux_client_forwards(sock
, 0) != 0) {
2192 error("%s: master forward request failed", __func__
);
2195 mux_client_request_session(sock
);
2197 case SSHMUX_COMMAND_STDIO_FWD
:
2198 mux_client_request_stdio_fwd(sock
);
2200 case SSHMUX_COMMAND_STOP
:
2201 mux_client_request_stop_listening(sock
);
2202 fprintf(stderr
, "Stop listening request sent.\r\n");
2204 case SSHMUX_COMMAND_CANCEL_FWD
:
2205 if (mux_client_forwards(sock
, 1) != 0)
2206 error("%s: master cancel forward request failed",
2210 fatal("unrecognised muxclient_command %d", muxclient_command
);