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efi - Add EFI run-time ABI support (3)
[dragonfly.git] / crypto / openssh / mux.c
blob98e3c0068263e277e0c4ce647b6fb55026a52ace
1 /* $OpenBSD: mux.c,v 1.60 2016/06/03 03:14:41 dtucker Exp $ */
2 /*
3 * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org>
4 *
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.
8 *
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.
16 */
17
18 /* ssh session multiplexing support */
19
20 /*
21 * TODO:
22 * - Better signalling from master to slave, especially passing of
23 * error messages
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
30 * sessions in master.
31 */
32
33 #include "includes.h"
34
35 #include <sys/types.h>
36 #include <sys/stat.h>
37 #include <sys/socket.h>
38 #include <sys/un.h>
39
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <signal.h>
43 #include <stdarg.h>
44 #include <stddef.h>
45 #include <stdlib.h>
46 #include <stdio.h>
47 #include <string.h>
48 #include <unistd.h>
49 #ifdef HAVE_PATHS_H
50 #include <paths.h>
51 #endif
52
53 #ifdef HAVE_POLL_H
54 #include <poll.h>
55 #else
56 # ifdef HAVE_SYS_POLL_H
57 # include <sys/poll.h>
58 # endif
59 #endif
60
61 #ifdef HAVE_UTIL_H
62 # include <util.h>
63 #endif
64
65 #include "openbsd-compat/sys-queue.h"
66 #include "xmalloc.h"
67 #include "log.h"
68 #include "ssh.h"
69 #include "ssh2.h"
70 #include "pathnames.h"
71 #include "misc.h"
72 #include "match.h"
73 #include "buffer.h"
74 #include "channels.h"
75 #include "msg.h"
76 #include "packet.h"
77 #include "monitor_fdpass.h"
78 #include "sshpty.h"
79 #include "key.h"
80 #include "readconf.h"
81 #include "clientloop.h"
82
83 /* from ssh.c */
84 extern int tty_flag;
85 extern Options options;
86 extern int stdin_null_flag;
87 extern char *host;
88 extern int subsystem_flag;
89 extern Buffer command;
90 extern volatile sig_atomic_t quit_pending;
91
92 /* Context for session open confirmation callback */
93 struct mux_session_confirm_ctx {
94 u_int want_tty;
95 u_int want_subsys;
96 u_int want_x_fwd;
97 u_int want_agent_fwd;
98 Buffer cmd;
99 char *term;
100 struct termios tio;
101 char **env;
102 u_int rid;
103 };
104
105 /* Context for stdio fwd open confirmation callback */
106 struct mux_stdio_confirm_ctx {
107 u_int rid;
108 };
109
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 */
115 };
116
117 /* fd to control socket */
118 int muxserver_sock = -1;
119
120 /* client request id */
121 u_int muxclient_request_id = 0;
122
123 /* Multiplexing control command */
124 u_int muxclient_command = 0;
125
126 /* Set when signalled. */
127 static volatile sig_atomic_t muxclient_terminate = 0;
128
129 /* PID of multiplex server */
130 static u_int muxserver_pid = 0;
131
132 static Channel *mux_listener_channel = NULL;
133
134 struct mux_master_state {
135 int hello_rcvd;
136 };
137
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
155
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
160
161 static void mux_session_confirm(int, int, void *);
162 static void mux_stdio_confirm(int, int, void *);
163
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 *);
172
173 static const struct {
174 u_int type;
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 },
185 { 0, NULL }
186 };
187
188 /* Cleanup callback fired on closure of mux slave _session_ channel */
189 /* ARGSUSED */
190 static void
191 mux_master_session_cleanup_cb(int cid, void *unused)
192 {
193 Channel *cc, *c = channel_by_id(cid);
194
195 debug3("%s: entering for channel %d", __func__, cid);
196 if (c == NULL)
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);
202 c->ctl_chan = -1;
203 cc->remote_id = -1;
204 chan_rcvd_oclose(cc);
205 }
206 channel_cancel_cleanup(c->self);
207 }
208
209 /* Cleanup callback fired on closure of mux slave _control_ channel */
210 /* ARGSUSED */
211 static void
212 mux_master_control_cleanup_cb(int cid, void *unused)
213 {
214 Channel *sc, *c = channel_by_id(cid);
215
216 debug3("%s: entering for channel %d", __func__, cid);
217 if (c == NULL)
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);
223 c->remote_id = -1;
224 sc->ctl_chan = -1;
225 if (sc->type != SSH_CHANNEL_OPEN &&
226 sc->type != SSH_CHANNEL_OPENING) {
227 debug2("%s: channel %d: not open", __func__, sc->self);
228 chan_mark_dead(sc);
229 } else {
230 if (sc->istate == CHAN_INPUT_OPEN)
231 chan_read_failed(sc);
232 if (sc->ostate == CHAN_OUTPUT_OPEN)
233 chan_write_failed(sc);
234 }
235 }
236 channel_cancel_cleanup(c->self);
237 }
238
239 /* Check mux client environment variables before passing them to mux master. */
240 static int
241 env_permitted(char *env)
242 {
243 int i, ret;
244 char name[1024], *cp;
245
246 if ((cp = strchr(env, '=')) == NULL || cp == env)
247 return 0;
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);
251 return 0;
252 }
253
254 for (i = 0; i < options.num_send_env; i++)
255 if (match_pattern(name, options.send_env[i]))
256 return 1;
257
258 return 0;
259 }
260
261 /* Mux master protocol message handlers */
262
263 static int
264 process_mux_master_hello(u_int rid, Channel *c, Buffer *m, Buffer *r)
265 {
266 u_int ver;
267 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
268
269 if (state == NULL)
270 fatal("%s: channel %d: c->mux_ctx == NULL", __func__, c->self);
271 if (state->hello_rcvd) {
272 error("%s: HELLO received twice", __func__);
273 return -1;
274 }
275 if (buffer_get_int_ret(&ver, m) != 0) {
276 malf:
277 error("%s: malformed message", __func__);
278 return -1;
279 }
280 if (ver != SSHMUX_VER) {
281 error("Unsupported multiplexing protocol version %d "
282 "(expected %d)", ver, SSHMUX_VER);
283 return -1;
284 }
285 debug2("%s: channel %d slave version %u", __func__, c->self, ver);
286
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);
291
292 if (name == NULL || value == NULL) {
293 free(name);
294 free(value);
295 goto malf;
296 }
297 debug2("Unrecognised slave extension \"%s\"", name);
298 free(name);
299 free(value);
300 }
301 state->hello_rcvd = 1;
302 return 0;
303 }
304
305 static int
306 process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r)
307 {
308 Channel *nc;
309 struct mux_session_confirm_ctx *cctx;
310 char *reserved, *cmd, *cp;
311 u_int i, j, len, env_len, escape_char, window, packetmax;
312 int new_fd[3];
313
314 /* Reply for SSHMUX_COMMAND_OPEN */
315 cctx = xcalloc(1, sizeof(*cctx));
316 cctx->term = NULL;
317 cctx->rid = rid;
318 cmd = reserved = NULL;
319 cctx->env = NULL;
320 env_len = 0;
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) {
329 malf:
330 free(cmd);
331 free(reserved);
332 for (j = 0; j < env_len; j++)
333 free(cctx->env[j]);
334 free(cctx->env);
335 free(cctx->term);
336 free(cctx);
337 error("%s: malformed message", __func__);
338 return -1;
339 }
340 free(reserved);
341 reserved = NULL;
342
343 while (buffer_len(m) > 0) {
344 #define MUX_MAX_ENV_VARS 4096
345 if ((cp = buffer_get_string_ret(m, &len)) == NULL)
346 goto malf;
347 if (!env_permitted(cp)) {
348 free(cp);
349 continue;
350 }
351 cctx->env = xreallocarray(cctx->env, env_len + 2,
352 sizeof(*cctx->env));
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);
358 break;
359 }
360 }
361
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);
366
367 buffer_init(&cctx->cmd);
368 buffer_append(&cctx->cmd, cmd, strlen(cmd));
369 free(cmd);
370 cmd = NULL;
371
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",
376 __func__, i);
377 for (j = 0; j < i; j++)
378 close(new_fd[j]);
379 for (j = 0; j < env_len; j++)
380 free(cctx->env[j]);
381 free(cctx->env);
382 free(cctx->term);
383 buffer_free(&cctx->cmd);
384 free(cctx);
385
386 /* prepare reply */
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");
391 return -1;
392 }
393 }
394
395 debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
396 new_fd[0], new_fd[1], new_fd[2]);
397
398 /* XXX support multiple child sessions in future */
399 if (c->remote_id != -1) {
400 debug2("%s: session already open", __func__);
401 /* prepare reply */
402 buffer_put_int(r, MUX_S_FAILURE);
403 buffer_put_int(r, rid);
404 buffer_put_cstring(r, "Multiple sessions not supported");
405 cleanup:
406 close(new_fd[0]);
407 close(new_fd[1]);
408 close(new_fd[2]);
409 free(cctx->term);
410 if (env_len != 0) {
411 for (i = 0; i < env_len; i++)
412 free(cctx->env[i]);
413 free(cctx->env);
414 }
415 buffer_free(&cctx->cmd);
416 free(cctx);
417 return 0;
418 }
419
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__);
424 /* prepare reply */
425 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
426 buffer_put_int(r, rid);
427 buffer_put_cstring(r, "Permission denied");
428 goto cleanup;
429 }
430 }
431
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));
435
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]);
443
444 window = CHAN_SES_WINDOW_DEFAULT;
445 packetmax = CHAN_SES_PACKET_DEFAULT;
446 if (cctx->want_tty) {
447 window >>= 1;
448 packetmax >>= 1;
449 }
450
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);
454
455 nc->ctl_chan = c->self; /* link session -> control channel */
456 c->remote_id = nc->self; /* link control -> session channel */
457
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));
463 }
464
465 debug2("%s: channel_new: %d linked to control channel %d",
466 __func__, nc->self, nc->ctl_chan);
467
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);
472
473 /* reply is deferred, sent by mux_session_confirm */
474 return 0;
475 }
476
477 static int
478 process_mux_alive_check(u_int rid, Channel *c, Buffer *m, Buffer *r)
479 {
480 debug2("%s: channel %d: alive check", __func__, c->self);
481
482 /* prepare reply */
483 buffer_put_int(r, MUX_S_ALIVE);
484 buffer_put_int(r, rid);
485 buffer_put_int(r, (u_int)getpid());
486
487 return 0;
488 }
489
490 static int
491 process_mux_terminate(u_int rid, Channel *c, Buffer *m, Buffer *r)
492 {
493 debug2("%s: channel %d: terminate request", __func__, c->self);
494
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? ",
498 host)) {
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");
503 return 0;
504 }
505 }
506
507 quit_pending = 1;
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 */
511 return 0;
512 }
513
514 static char *
515 format_forward(u_int ftype, struct Forward *fwd)
516 {
517 char *ret;
518
519 switch (ftype) {
520 case MUX_FWD_LOCAL:
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);
528 break;
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);
534 break;
535 case MUX_FWD_REMOTE:
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,
540 fwd->listen_port,
541 (fwd->connect_path != NULL) ? fwd->connect_path :
542 fwd->connect_host, fwd->connect_port);
543 break;
544 default:
545 fatal("%s: unknown forward type %u", __func__, ftype);
546 }
547 return ret;
548 }
549
550 static int
551 compare_host(const char *a, const char *b)
552 {
553 if (a == NULL && b == NULL)
554 return 1;
555 if (a == NULL || b == NULL)
556 return 0;
557 return strcmp(a, b) == 0;
558 }
559
560 static int
561 compare_forward(struct Forward *a, struct Forward *b)
562 {
563 if (!compare_host(a->listen_host, b->listen_host))
564 return 0;
565 if (!compare_host(a->listen_path, b->listen_path))
566 return 0;
567 if (a->listen_port != b->listen_port)
568 return 0;
569 if (!compare_host(a->connect_host, b->connect_host))
570 return 0;
571 if (!compare_host(a->connect_path, b->connect_path))
572 return 0;
573 if (a->connect_port != b->connect_port)
574 return 0;
575
576 return 1;
577 }
578
579 static void
580 mux_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
581 {
582 struct mux_channel_confirm_ctx *fctx = ctxt;
583 char *failmsg = NULL;
584 struct Forward *rfwd;
585 Channel *c;
586 Buffer out;
587
588 if ((c = channel_by_id(fctx->cid)) == NULL) {
589 /* no channel for reply */
590 error("%s: unknown channel", __func__);
591 return;
592 }
593 buffer_init(&out);
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);
598 goto fail;
599 }
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);
616 } else {
617 buffer_put_int(&out, MUX_S_OK);
618 buffer_put_int(&out, fctx->rid);
619 }
620 goto out;
621 } else {
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);
627 else
628 xasprintf(&failmsg, "remote port forwarding failed for "
629 "listen port %d", rfwd->listen_port);
630
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);
635
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));
641 }
642 fail:
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);
647 free(failmsg);
648 out:
649 buffer_put_string(&c->output, buffer_ptr(&out), buffer_len(&out));
650 buffer_free(&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 */
654 }
655
656 static int
657 process_mux_open_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
658 {
659 struct Forward fwd;
660 char *fwd_desc = NULL;
661 char *listen_addr, *connect_addr;
662 u_int ftype;
663 u_int lport, cport;
664 int i, ret = 0, freefwd = 1;
665
666 memset(&fwd, 0, sizeof(fwd));
667
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__);
677 ret = -1;
678 goto out;
679 }
680 if (*listen_addr == '\0') {
681 free(listen_addr);
682 listen_addr = NULL;
683 }
684 if (*connect_addr == '\0') {
685 free(connect_addr);
686 connect_addr = NULL;
687 }
688
689 memset(&fwd, 0, sizeof(fwd));
690 fwd.listen_port = lport;
691 if (fwd.listen_port == PORT_STREAMLOCAL)
692 fwd.listen_path = listen_addr;
693 else
694 fwd.listen_host = listen_addr;
695 fwd.connect_port = cport;
696 if (fwd.connect_port == PORT_STREAMLOCAL)
697 fwd.connect_path = connect_addr;
698 else
699 fwd.connect_host = connect_addr;
700
701 debug2("%s: channel %d: request %s", __func__, c->self,
702 (fwd_desc = format_forward(ftype, &fwd)));
703
704 if (ftype != MUX_FWD_LOCAL && ftype != MUX_FWD_REMOTE &&
705 ftype != MUX_FWD_DYNAMIC) {
706 logit("%s: invalid forwarding type %u", __func__, ftype);
707 invalid:
708 free(listen_addr);
709 free(connect_addr);
710 buffer_put_int(r, MUX_S_FAILURE);
711 buffer_put_int(r, rid);
712 buffer_put_cstring(r, "Invalid forwarding request");
713 return 0;
714 }
715 if (ftype == MUX_FWD_DYNAMIC && fwd.listen_path) {
716 logit("%s: streamlocal and dynamic forwards "
717 "are mutually exclusive", __func__);
718 goto invalid;
719 }
720 if (fwd.listen_port != PORT_STREAMLOCAL && fwd.listen_port >= 65536) {
721 logit("%s: invalid listen port %u", __func__,
722 fwd.listen_port);
723 goto invalid;
724 }
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__,
728 fwd.connect_port);
729 goto invalid;
730 }
731 if (ftype != MUX_FWD_DYNAMIC && fwd.connect_host == NULL && fwd.connect_path == NULL) {
732 logit("%s: missing connect host", __func__);
733 goto invalid;
734 }
735
736 /* Skip forwards that have already been requested */
737 switch (ftype) {
738 case MUX_FWD_LOCAL:
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)) {
743 exists:
744 debug2("%s: found existing forwarding",
745 __func__);
746 buffer_put_int(r, MUX_S_OK);
747 buffer_put_int(r, rid);
748 goto out;
749 }
750 }
751 break;
752 case MUX_FWD_REMOTE:
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)
757 goto exists;
758 debug2("%s: found allocated port",
759 __func__);
760 buffer_put_int(r, MUX_S_REMOTE_PORT);
761 buffer_put_int(r, rid);
762 buffer_put_int(r,
763 options.remote_forwards[i].allocated_port);
764 goto out;
765 }
766 }
767 break;
768 }
769
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");
777 goto out;
778 }
779 }
780
781 if (ftype == MUX_FWD_LOCAL || ftype == MUX_FWD_DYNAMIC) {
782 if (!channel_setup_local_fwd_listener(&fwd,
783 &options.fwd_opts)) {
784 fail:
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");
789 goto out;
790 }
791 add_local_forward(&options, &fwd);
792 freefwd = 0;
793 } else {
794 struct mux_channel_confirm_ctx *fctx;
795
796 fwd.handle = channel_request_remote_forwarding(&fwd);
797 if (fwd.handle < 0)
798 goto fail;
799 add_remote_forward(&options, &fwd);
800 fctx = xcalloc(1, sizeof(*fctx));
801 fctx->cid = c->self;
802 fctx->rid = rid;
803 fctx->fid = options.num_remote_forwards - 1;
804 client_register_global_confirm(mux_confirm_remote_forward,
805 fctx);
806 freefwd = 0;
807 c->mux_pause = 1; /* wait for mux_confirm_remote_forward */
808 /* delayed reply in mux_confirm_remote_forward */
809 goto out;
810 }
811 buffer_put_int(r, MUX_S_OK);
812 buffer_put_int(r, rid);
813 out:
814 free(fwd_desc);
815 if (freefwd) {
816 free(fwd.listen_host);
817 free(fwd.listen_path);
818 free(fwd.connect_host);
819 free(fwd.connect_path);
820 }
821 return ret;
822 }
823
824 static int
825 process_mux_close_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
826 {
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;
831 u_int ftype;
832 int i, ret = 0;
833 u_int lport, cport;
834
835 memset(&fwd, 0, sizeof(fwd));
836
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__);
845 ret = -1;
846 goto out;
847 }
848
849 if (*listen_addr == '\0') {
850 free(listen_addr);
851 listen_addr = NULL;
852 }
853 if (*connect_addr == '\0') {
854 free(connect_addr);
855 connect_addr = NULL;
856 }
857
858 memset(&fwd, 0, sizeof(fwd));
859 fwd.listen_port = lport;
860 if (fwd.listen_port == PORT_STREAMLOCAL)
861 fwd.listen_path = listen_addr;
862 else
863 fwd.listen_host = listen_addr;
864 fwd.connect_port = cport;
865 if (fwd.connect_port == PORT_STREAMLOCAL)
866 fwd.connect_path = connect_addr;
867 else
868 fwd.connect_host = connect_addr;
869
870 debug2("%s: channel %d: request cancel %s", __func__, c->self,
871 (fwd_desc = format_forward(ftype, &fwd)));
872
873 /* make sure this has been requested */
874 found_fwd = NULL;
875 switch (ftype) {
876 case MUX_FWD_LOCAL:
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;
882 break;
883 }
884 }
885 break;
886 case MUX_FWD_REMOTE:
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;
891 break;
892 }
893 }
894 break;
895 }
896
897 if (found_fwd == NULL)
898 error_reason = "port not forwarded";
899 else if (ftype == MUX_FWD_REMOTE) {
900 /*
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.
905 */
906 if (channel_request_rforward_cancel(found_fwd) == -1)
907 error_reason = "port not in permitted opens";
908 } else { /* local and dynamic forwards */
909 /* Ditto */
910 if (channel_cancel_lport_listener(&fwd, fwd.connect_port,
911 &options.fwd_opts) == -1)
912 error_reason = "port not found";
913 }
914
915 if (error_reason == NULL) {
916 buffer_put_int(r, MUX_S_OK);
917 buffer_put_int(r, rid);
918
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;
926 } else {
927 buffer_put_int(r, MUX_S_FAILURE);
928 buffer_put_int(r, rid);
929 buffer_put_cstring(r, error_reason);
930 }
931 out:
932 free(fwd_desc);
933 free(listen_addr);
934 free(connect_addr);
935
936 return ret;
937 }
938
939 static int
940 process_mux_stdio_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
941 {
942 Channel *nc;
943 char *reserved, *chost;
944 u_int cport, i, j;
945 int new_fd[2];
946 struct mux_stdio_confirm_ctx *cctx;
947
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) {
952 free(reserved);
953 free(chost);
954 error("%s: malformed message", __func__);
955 return -1;
956 }
957 free(reserved);
958
959 debug2("%s: channel %d: request stdio fwd to %s:%u",
960 __func__, c->self, chost, cport);
961
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",
966 __func__, i);
967 for (j = 0; j < i; j++)
968 close(new_fd[j]);
969 free(chost);
970
971 /* prepare reply */
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");
976 return -1;
977 }
978 }
979
980 debug3("%s: got fds stdin %d, stdout %d", __func__,
981 new_fd[0], new_fd[1]);
982
983 /* XXX support multiple child sessions in future */
984 if (c->remote_id != -1) {
985 debug2("%s: session already open", __func__);
986 /* prepare reply */
987 buffer_put_int(r, MUX_S_FAILURE);
988 buffer_put_int(r, rid);
989 buffer_put_cstring(r, "Multiple sessions not supported");
990 cleanup:
991 close(new_fd[0]);
992 close(new_fd[1]);
993 free(chost);
994 return 0;
995 }
996
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? ",
1000 chost, cport)) {
1001 debug2("%s: stdio fwd refused by user", __func__);
1002 /* prepare reply */
1003 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
1004 buffer_put_int(r, rid);
1005 buffer_put_cstring(r, "Permission denied");
1006 goto cleanup;
1007 }
1008 }
1009
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]);
1015
1016 nc = channel_connect_stdio_fwd(chost, cport, new_fd[0], new_fd[1]);
1017
1018 nc->ctl_chan = c->self; /* link session -> control channel */
1019 c->remote_id = nc->self; /* link control -> session channel */
1020
1021 debug2("%s: channel_new: %d linked to control channel %d",
1022 __func__, nc->self, nc->ctl_chan);
1023
1024 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
1025
1026 cctx = xcalloc(1, sizeof(*cctx));
1027 cctx->rid = rid;
1028 channel_register_open_confirm(nc->self, mux_stdio_confirm, cctx);
1029 c->mux_pause = 1; /* stop handling messages until open_confirm done */
1030
1031 /* reply is deferred, sent by mux_session_confirm */
1032 return 0;
1033 }
1034
1035 /* Callback on open confirmation in mux master for a mux stdio fwd session. */
1036 static void
1037 mux_stdio_confirm(int id, int success, void *arg)
1038 {
1039 struct mux_stdio_confirm_ctx *cctx = arg;
1040 Channel *c, *cc;
1041 Buffer reply;
1042
1043 if (cctx == NULL)
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__,
1049 id, c->ctl_chan);
1050
1051 if (!success) {
1052 debug3("%s: sending failure reply", __func__);
1053 /* prepare reply */
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");
1058 goto done;
1059 }
1060
1061 debug3("%s: sending success reply", __func__);
1062 /* prepare reply */
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);
1067
1068 done:
1069 /* Send reply */
1070 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
1071 buffer_free(&reply);
1072
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;
1077 free(cctx);
1078 }
1079
1080 static int
1081 process_mux_stop_listening(u_int rid, Channel *c, Buffer *m, Buffer *r)
1082 {
1083 debug("%s: channel %d: stop listening", __func__, c->self);
1084
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");
1093 return 0;
1094 }
1095 }
1096
1097 if (mux_listener_channel != NULL) {
1098 channel_free(mux_listener_channel);
1099 client_stop_mux();
1100 free(options.control_path);
1101 options.control_path = NULL;
1102 mux_listener_channel = NULL;
1103 muxserver_sock = -1;
1104 }
1105
1106 /* prepare reply */
1107 buffer_put_int(r, MUX_S_OK);
1108 buffer_put_int(r, rid);
1109
1110 return 0;
1111 }
1112
1113 /* Channel callbacks fired on read/write from mux slave fd */
1114 static int
1115 mux_master_read_cb(Channel *c)
1116 {
1117 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
1118 Buffer in, out;
1119 const u_char *ptr;
1120 u_int type, rid, have, i;
1121 int ret = -1;
1122
1123 /* Setup ctx and */
1124 if (c->mux_ctx == NULL) {
1125 state = xcalloc(1, sizeof(*state));
1126 c->mux_ctx = state;
1127 channel_register_cleanup(c->self,
1128 mux_master_control_cleanup_cb, 0);
1129
1130 /* Send hello */
1131 buffer_init(&out);
1132 buffer_put_int(&out, MUX_MSG_HELLO);
1133 buffer_put_int(&out, SSHMUX_VER);
1134 /* no extensions */
1135 buffer_put_string(&c->output, buffer_ptr(&out),
1136 buffer_len(&out));
1137 buffer_free(&out);
1138 debug3("%s: channel %d: hello sent", __func__, c->self);
1139 return 0;
1140 }
1141
1142 buffer_init(&in);
1143 buffer_init(&out);
1144
1145 /* Channel code ensures that we receive whole packets */
1146 if ((ptr = buffer_get_string_ptr_ret(&c->input, &have)) == NULL) {
1147 malf:
1148 error("%s: malformed message", __func__);
1149 goto out;
1150 }
1151 buffer_append(&in, ptr, have);
1152
1153 if (buffer_get_int_ret(&type, &in) != 0)
1154 goto malf;
1155 debug3("%s: channel %d packet type 0x%08x len %u",
1156 __func__, c->self, type, buffer_len(&in));
1157
1158 if (type == MUX_MSG_HELLO)
1159 rid = 0;
1160 else {
1161 if (!state->hello_rcvd) {
1162 error("%s: expected MUX_MSG_HELLO(0x%08x), "
1163 "received 0x%08x", __func__, MUX_MSG_HELLO, type);
1164 goto out;
1165 }
1166 if (buffer_get_int_ret(&rid, &in) != 0)
1167 goto malf;
1168 }
1169
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);
1173 break;
1174 }
1175 }
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");
1181 ret = 0;
1182 }
1183 /* Enqueue reply packet */
1184 if (buffer_len(&out) != 0) {
1185 buffer_put_string(&c->output, buffer_ptr(&out),
1186 buffer_len(&out));
1187 }
1188 out:
1189 buffer_free(&in);
1190 buffer_free(&out);
1191 return ret;
1192 }
1193
1194 void
1195 mux_exit_message(Channel *c, int exitval)
1196 {
1197 Buffer m;
1198 Channel *mux_chan;
1199
1200 debug3("%s: channel %d: exit message, exitval %d", __func__, c->self,
1201 exitval);
1202
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);
1206
1207 /* Append exit message packet to control socket output queue */
1208 buffer_init(&m);
1209 buffer_put_int(&m, MUX_S_EXIT_MESSAGE);
1210 buffer_put_int(&m, c->self);
1211 buffer_put_int(&m, exitval);
1212
1213 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1214 buffer_free(&m);
1215 }
1216
1217 void
1218 mux_tty_alloc_failed(Channel *c)
1219 {
1220 Buffer m;
1221 Channel *mux_chan;
1222
1223 debug3("%s: channel %d: TTY alloc failed", __func__, c->self);
1224
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);
1228
1229 /* Append exit message packet to control socket output queue */
1230 buffer_init(&m);
1231 buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL);
1232 buffer_put_int(&m, c->self);
1233
1234 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1235 buffer_free(&m);
1236 }
1237
1238 /* Prepare a mux master to listen on a Unix domain socket. */
1239 void
1240 muxserver_listen(void)
1241 {
1242 mode_t old_umask;
1243 char *orig_control_path = options.control_path;
1244 char rbuf[16+1];
1245 u_int i, r;
1246 int oerrno;
1247
1248 if (options.control_path == NULL ||
1249 options.control_master == SSHCTL_MASTER_NO)
1250 return;
1251
1252 debug("setting up multiplex master socket");
1253
1254 /*
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.
1259 */
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 :
1264 '0' + r - 26 - 26;
1265 }
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);
1270
1271 old_umask = umask(0177);
1272 muxserver_sock = unix_listener(options.control_path, 64, 0);
1273 oerrno = errno;
1274 umask(old_umask);
1275 if (muxserver_sock < 0) {
1276 if (oerrno == EINVAL || oerrno == EADDRINUSE) {
1277 error("ControlSocket %s already exists, "
1278 "disabling multiplexing", options.control_path);
1279 disable_mux_master:
1280 if (muxserver_sock != -1) {
1281 close(muxserver_sock);
1282 muxserver_sock = -1;
1283 }
1284 free(orig_control_path);
1285 free(options.control_path);
1286 options.control_path = NULL;
1287 options.control_master = SSHCTL_MASTER_NO;
1288 return;
1289 } else {
1290 /* unix_listener() logs the error */
1291 cleanup_exit(255);
1292 }
1293 }
1294
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,
1300 strerror(errno));
1301 }
1302 error("ControlSocket %s already exists, disabling multiplexing",
1303 orig_control_path);
1304 unlink(options.control_path);
1305 goto disable_mux_master;
1306 }
1307 unlink(options.control_path);
1308 free(options.control_path);
1309 options.control_path = orig_control_path;
1310
1311 set_nonblock(muxserver_sock);
1312
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);
1320 }
1321
1322 /* Callback on open confirmation in mux master for a mux client session. */
1323 static void
1324 mux_session_confirm(int id, int success, void *arg)
1325 {
1326 struct mux_session_confirm_ctx *cctx = arg;
1327 const char *display;
1328 Channel *c, *cc;
1329 int i;
1330 Buffer reply;
1331
1332 if (cctx == NULL)
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__,
1338 id, c->ctl_chan);
1339
1340 if (!success) {
1341 debug3("%s: sending failure reply", __func__);
1342 /* prepare reply */
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");
1347 goto done;
1348 }
1349
1350 display = getenv("DISPLAY");
1351 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
1352 char *proto, *data;
1353
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 "
1360 "spoofing.");
1361 x11_request_forwarding_with_spoofing(id, display, proto,
1362 data, 1);
1363 /* XXX exit_on_forward_failure */
1364 client_expect_confirm(id, "X11 forwarding",
1365 CONFIRM_WARN);
1366 }
1367 }
1368
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);
1372 packet_send();
1373 }
1374
1375 client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
1376 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env);
1377
1378 debug3("%s: sending success reply", __func__);
1379 /* prepare reply */
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);
1384
1385 done:
1386 /* Send reply */
1387 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
1388 buffer_free(&reply);
1389
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);
1395 free(cctx->term);
1396 if (cctx->env != NULL) {
1397 for (i = 0; cctx->env[i] != NULL; i++)
1398 free(cctx->env[i]);
1399 free(cctx->env);
1400 }
1401 free(cctx);
1402 }
1403
1404 /* ** Multiplexing client support */
1405
1406 /* Exit signal handler */
1407 static void
1408 control_client_sighandler(int signo)
1409 {
1410 muxclient_terminate = signo;
1411 }
1412
1413 /*
1414 * Relay signal handler - used to pass some signals from mux client to
1415 * mux master.
1416 */
1417 static void
1418 control_client_sigrelay(int signo)
1419 {
1420 int save_errno = errno;
1421
1422 if (muxserver_pid > 1)
1423 kill(muxserver_pid, signo);
1424
1425 errno = save_errno;
1426 }
1427
1428 static int
1429 mux_client_read(int fd, Buffer *b, u_int need)
1430 {
1431 u_int have;
1432 ssize_t len;
1433 u_char *p;
1434 struct pollfd pfd;
1435
1436 pfd.fd = fd;
1437 pfd.events = POLLIN;
1438 p = buffer_append_space(b, need);
1439 for (have = 0; have < need; ) {
1440 if (muxclient_terminate) {
1441 errno = EINTR;
1442 return -1;
1443 }
1444 len = read(fd, p + have, need - have);
1445 if (len < 0) {
1446 switch (errno) {
1447 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1448 case EWOULDBLOCK:
1449 #endif
1450 case EAGAIN:
1451 (void)poll(&pfd, 1, -1);
1452 /* FALLTHROUGH */
1453 case EINTR:
1454 continue;
1455 default:
1456 return -1;
1457 }
1458 }
1459 if (len == 0) {
1460 errno = EPIPE;
1461 return -1;
1462 }
1463 have += (u_int)len;
1464 }
1465 return 0;
1466 }
1467
1468 static int
1469 mux_client_write_packet(int fd, Buffer *m)
1470 {
1471 Buffer queue;
1472 u_int have, need;
1473 int oerrno, len;
1474 u_char *ptr;
1475 struct pollfd pfd;
1476
1477 pfd.fd = fd;
1478 pfd.events = POLLOUT;
1479 buffer_init(&queue);
1480 buffer_put_string(&queue, buffer_ptr(m), buffer_len(m));
1481
1482 need = buffer_len(&queue);
1483 ptr = buffer_ptr(&queue);
1484
1485 for (have = 0; have < need; ) {
1486 if (muxclient_terminate) {
1487 buffer_free(&queue);
1488 errno = EINTR;
1489 return -1;
1490 }
1491 len = write(fd, ptr + have, need - have);
1492 if (len < 0) {
1493 switch (errno) {
1494 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1495 case EWOULDBLOCK:
1496 #endif
1497 case EAGAIN:
1498 (void)poll(&pfd, 1, -1);
1499 /* FALLTHROUGH */
1500 case EINTR:
1501 continue;
1502 default:
1503 oerrno = errno;
1504 buffer_free(&queue);
1505 errno = oerrno;
1506 return -1;
1507 }
1508 }
1509 if (len == 0) {
1510 buffer_free(&queue);
1511 errno = EPIPE;
1512 return -1;
1513 }
1514 have += (u_int)len;
1515 }
1516 buffer_free(&queue);
1517 return 0;
1518 }
1519
1520 static int
1521 mux_client_read_packet(int fd, Buffer *m)
1522 {
1523 Buffer queue;
1524 u_int need, have;
1525 const u_char *ptr;
1526 int oerrno;
1527
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__,
1532 strerror(errno));
1533 buffer_free(&queue);
1534 errno = oerrno;
1535 return -1;
1536 }
1537 need = get_u32(buffer_ptr(&queue));
1538 if (mux_client_read(fd, &queue, need) != 0) {
1539 oerrno = errno;
1540 debug3("%s: read body failed: %s", __func__, strerror(errno));
1541 buffer_free(&queue);
1542 errno = oerrno;
1543 return -1;
1544 }
1545 ptr = buffer_get_string_ptr(&queue, &have);
1546 buffer_append(m, ptr, have);
1547 buffer_free(&queue);
1548 return 0;
1549 }
1550
1551 static int
1552 mux_client_hello_exchange(int fd)
1553 {
1554 Buffer m;
1555 u_int type, ver;
1556
1557 buffer_init(&m);
1558 buffer_put_int(&m, MUX_MSG_HELLO);
1559 buffer_put_int(&m, SSHMUX_VER);
1560 /* no extensions */
1561
1562 if (mux_client_write_packet(fd, &m) != 0)
1563 fatal("%s: write packet: %s", __func__, strerror(errno));
1564
1565 buffer_clear(&m);
1566
1567 /* Read their HELLO */
1568 if (mux_client_read_packet(fd, &m) != 0) {
1569 buffer_free(&m);
1570 return -1;
1571 }
1572
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);
1586
1587 debug2("Unrecognised master extension \"%s\"", name);
1588 free(name);
1589 free(value);
1590 }
1591 buffer_free(&m);
1592 return 0;
1593 }
1594
1595 static u_int
1596 mux_client_request_alive(int fd)
1597 {
1598 Buffer m;
1599 char *e;
1600 u_int pid, type, rid;
1601
1602 debug3("%s: entering", __func__);
1603
1604 buffer_init(&m);
1605 buffer_put_int(&m, MUX_C_ALIVE_CHECK);
1606 buffer_put_int(&m, muxclient_request_id);
1607
1608 if (mux_client_write_packet(fd, &m) != 0)
1609 fatal("%s: write packet: %s", __func__, strerror(errno));
1610
1611 buffer_clear(&m);
1612
1613 /* Read their reply */
1614 if (mux_client_read_packet(fd, &m) != 0) {
1615 buffer_free(&m);
1616 return 0;
1617 }
1618
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);
1623 }
1624
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);
1629 buffer_free(&m);
1630
1631 debug3("%s: done pid = %u", __func__, pid);
1632
1633 muxclient_request_id++;
1634
1635 return pid;
1636 }
1637
1638 static void
1639 mux_client_request_terminate(int fd)
1640 {
1641 Buffer m;
1642 char *e;
1643 u_int type, rid;
1644
1645 debug3("%s: entering", __func__);
1646
1647 buffer_init(&m);
1648 buffer_put_int(&m, MUX_C_TERMINATE);
1649 buffer_put_int(&m, muxclient_request_id);
1650
1651 if (mux_client_write_packet(fd, &m) != 0)
1652 fatal("%s: write packet: %s", __func__, strerror(errno));
1653
1654 buffer_clear(&m);
1655
1656 /* Read their reply */
1657 if (mux_client_read_packet(fd, &m) != 0) {
1658 /* Remote end exited already */
1659 if (errno == EPIPE) {
1660 buffer_free(&m);
1661 return;
1662 }
1663 fatal("%s: read from master failed: %s",
1664 __func__, strerror(errno));
1665 }
1666
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);
1671 switch (type) {
1672 case MUX_S_OK:
1673 break;
1674 case MUX_S_PERMISSION_DENIED:
1675 e = buffer_get_string(&m, NULL);
1676 fatal("Master refused termination request: %s", e);
1677 case MUX_S_FAILURE:
1678 e = buffer_get_string(&m, NULL);
1679 fatal("%s: termination request failed: %s", __func__, e);
1680 default:
1681 fatal("%s: unexpected response from master 0x%08x",
1682 __func__, type);
1683 }
1684 buffer_free(&m);
1685 muxclient_request_id++;
1686 }
1687
1688 static int
1689 mux_client_forward(int fd, int cancel_flag, u_int ftype, struct Forward *fwd)
1690 {
1691 Buffer m;
1692 char *e, *fwd_desc;
1693 u_int type, rid;
1694
1695 fwd_desc = format_forward(ftype, fwd);
1696 debug("Requesting %s %s",
1697 cancel_flag ? "cancellation of" : "forwarding of", fwd_desc);
1698 free(fwd_desc);
1699
1700 buffer_init(&m);
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);
1706 } else {
1707 buffer_put_cstring(&m,
1708 fwd->listen_host == NULL ? "" :
1709 (*fwd->listen_host == '\0' ? "*" : fwd->listen_host));
1710 }
1711 buffer_put_int(&m, fwd->listen_port);
1712 if (fwd->connect_path != NULL) {
1713 buffer_put_cstring(&m, fwd->connect_path);
1714 } else {
1715 buffer_put_cstring(&m,
1716 fwd->connect_host == NULL ? "" : fwd->connect_host);
1717 }
1718 buffer_put_int(&m, fwd->connect_port);
1719
1720 if (mux_client_write_packet(fd, &m) != 0)
1721 fatal("%s: write packet: %s", __func__, strerror(errno));
1722
1723 buffer_clear(&m);
1724
1725 /* Read their reply */
1726 if (mux_client_read_packet(fd, &m) != 0) {
1727 buffer_free(&m);
1728 return -1;
1729 }
1730
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);
1735 switch (type) {
1736 case MUX_S_OK:
1737 break;
1738 case MUX_S_REMOTE_PORT:
1739 if (cancel_flag)
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 : "",
1745 fwd->connect_port);
1746 if (muxclient_command == SSHMUX_COMMAND_FORWARD)
1747 fprintf(stdout, "%i\n", fwd->allocated_port);
1748 break;
1749 case MUX_S_PERMISSION_DENIED:
1750 e = buffer_get_string(&m, NULL);
1751 buffer_free(&m);
1752 error("Master refused forwarding request: %s", e);
1753 return -1;
1754 case MUX_S_FAILURE:
1755 e = buffer_get_string(&m, NULL);
1756 buffer_free(&m);
1757 error("%s: forwarding request failed: %s", __func__, e);
1758 return -1;
1759 default:
1760 fatal("%s: unexpected response from master 0x%08x",
1761 __func__, type);
1762 }
1763 buffer_free(&m);
1764
1765 muxclient_request_id++;
1766 return 0;
1767 }
1768
1769 static int
1770 mux_client_forwards(int fd, int cancel_flag)
1771 {
1772 int i, ret = 0;
1773
1774 debug3("%s: %s forwardings: %d local, %d remote", __func__,
1775 cancel_flag ? "cancel" : "request",
1776 options.num_local_forwards, options.num_remote_forwards);
1777
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)
1784 ret = -1;
1785 }
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)
1789 ret = -1;
1790 }
1791 return ret;
1792 }
1793
1794 static int
1795 mux_client_request_session(int fd)
1796 {
1797 Buffer m;
1798 char *e, *term;
1799 u_int i, rid, sid, esid, exitval, type, exitval_seen;
1800 extern char **environ;
1801 int devnull, rawmode;
1802
1803 debug3("%s: entering", __func__);
1804
1805 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
1806 error("%s: master alive request failed", __func__);
1807 return -1;
1808 }
1809
1810 signal(SIGPIPE, SIG_IGN);
1811
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)
1818 close(devnull);
1819 }
1820
1821 term = getenv("TERM");
1822
1823 buffer_init(&m);
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));
1835
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]);
1841 }
1842 }
1843 }
1844
1845 if (mux_client_write_packet(fd, &m) != 0)
1846 fatal("%s: write packet: %s", __func__, strerror(errno));
1847
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__);
1853
1854 debug3("%s: session request sent", __func__);
1855
1856 /* Read their reply */
1857 buffer_clear(&m);
1858 if (mux_client_read_packet(fd, &m) != 0) {
1859 error("%s: read from master failed: %s",
1860 __func__, strerror(errno));
1861 buffer_free(&m);
1862 return -1;
1863 }
1864
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);
1869 switch (type) {
1870 case MUX_S_SESSION_OPENED:
1871 sid = buffer_get_int(&m);
1872 debug("%s: master session id: %u", __func__, sid);
1873 break;
1874 case MUX_S_PERMISSION_DENIED:
1875 e = buffer_get_string(&m, NULL);
1876 buffer_free(&m);
1877 error("Master refused session request: %s", e);
1878 return -1;
1879 case MUX_S_FAILURE:
1880 e = buffer_get_string(&m, NULL);
1881 buffer_free(&m);
1882 error("%s: session request failed: %s", __func__, e);
1883 return -1;
1884 default:
1885 buffer_free(&m);
1886 error("%s: unexpected response from master 0x%08x",
1887 __func__, type);
1888 return -1;
1889 }
1890 muxclient_request_id++;
1891
1892 if (pledge("stdio proc tty", NULL) == -1)
1893 fatal("%s pledge(): %s", __func__, strerror(errno));
1894 platform_pledge_mux();
1895
1896 signal(SIGHUP, control_client_sighandler);
1897 signal(SIGINT, control_client_sighandler);
1898 signal(SIGTERM, control_client_sighandler);
1899 signal(SIGWINCH, control_client_sigrelay);
1900
1901 rawmode = tty_flag;
1902 if (tty_flag)
1903 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1904
1905 /*
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).
1911 */
1912 for (exitval = 255, exitval_seen = 0;;) {
1913 buffer_clear(&m);
1914 if (mux_client_read_packet(fd, &m) != 0)
1915 break;
1916 type = buffer_get_int(&m);
1917 switch (type) {
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 ==
1924 REQUEST_TTY_FORCE);
1925 rawmode = 0;
1926 continue;
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);
1932 if (exitval_seen)
1933 fatal("%s: exitval sent twice", __func__);
1934 exitval = buffer_get_int(&m);
1935 exitval_seen = 1;
1936 continue;
1937 default:
1938 e = buffer_get_string(&m, NULL);
1939 fatal("%s: master returned error: %s", __func__, e);
1940 }
1941 }
1942
1943 close(fd);
1944 if (rawmode)
1945 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1946
1947 if (muxclient_terminate) {
1948 debug2("Exiting on signal %d", muxclient_terminate);
1949 exitval = 255;
1950 } else if (!exitval_seen) {
1951 debug2("Control master terminated unexpectedly");
1952 exitval = 255;
1953 } else
1954 debug2("Received exit status from master %d", exitval);
1955
1956 if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1957 fprintf(stderr, "Shared connection to %s closed.\r\n", host);
1958
1959 exit(exitval);
1960 }
1961
1962 static int
1963 mux_client_request_stdio_fwd(int fd)
1964 {
1965 Buffer m;
1966 char *e;
1967 u_int type, rid, sid;
1968 int devnull;
1969
1970 debug3("%s: entering", __func__);
1971
1972 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
1973 error("%s: master alive request failed", __func__);
1974 return -1;
1975 }
1976
1977 signal(SIGPIPE, SIG_IGN);
1978
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)
1985 close(devnull);
1986 }
1987
1988 buffer_init(&m);
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);
1994
1995 if (mux_client_write_packet(fd, &m) != 0)
1996 fatal("%s: write packet: %s", __func__, strerror(errno));
1997
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__);
2002
2003 if (pledge("stdio proc tty", NULL) == -1)
2004 fatal("%s pledge(): %s", __func__, strerror(errno));
2005 platform_pledge_mux();
2006
2007 debug3("%s: stdio forward request sent", __func__);
2008
2009 /* Read their reply */
2010 buffer_clear(&m);
2011
2012 if (mux_client_read_packet(fd, &m) != 0) {
2013 error("%s: read from master failed: %s",
2014 __func__, strerror(errno));
2015 buffer_free(&m);
2016 return -1;
2017 }
2018
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);
2023 switch (type) {
2024 case MUX_S_SESSION_OPENED:
2025 sid = buffer_get_int(&m);
2026 debug("%s: master session id: %u", __func__, sid);
2027 break;
2028 case MUX_S_PERMISSION_DENIED:
2029 e = buffer_get_string(&m, NULL);
2030 buffer_free(&m);
2031 fatal("Master refused stdio forwarding request: %s", e);
2032 case MUX_S_FAILURE:
2033 e = buffer_get_string(&m, NULL);
2034 buffer_free(&m);
2035 fatal("Stdio forwarding request failed: %s", e);
2036 default:
2037 buffer_free(&m);
2038 error("%s: unexpected response from master 0x%08x",
2039 __func__, type);
2040 return -1;
2041 }
2042 muxclient_request_id++;
2043
2044 signal(SIGHUP, control_client_sighandler);
2045 signal(SIGINT, control_client_sighandler);
2046 signal(SIGTERM, control_client_sighandler);
2047 signal(SIGWINCH, control_client_sigrelay);
2048
2049 /*
2050 * Stick around until the controlee closes the client_fd.
2051 */
2052 buffer_clear(&m);
2053 if (mux_client_read_packet(fd, &m) != 0) {
2054 if (errno == EPIPE ||
2055 (errno == EINTR && muxclient_terminate != 0))
2056 return 0;
2057 fatal("%s: mux_client_read_packet: %s",
2058 __func__, strerror(errno));
2059 }
2060 fatal("%s: master returned unexpected message %u", __func__, type);
2061 }
2062
2063 static void
2064 mux_client_request_stop_listening(int fd)
2065 {
2066 Buffer m;
2067 char *e;
2068 u_int type, rid;
2069
2070 debug3("%s: entering", __func__);
2071
2072 buffer_init(&m);
2073 buffer_put_int(&m, MUX_C_STOP_LISTENING);
2074 buffer_put_int(&m, muxclient_request_id);
2075
2076 if (mux_client_write_packet(fd, &m) != 0)
2077 fatal("%s: write packet: %s", __func__, strerror(errno));
2078
2079 buffer_clear(&m);
2080
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));
2085
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);
2090 switch (type) {
2091 case MUX_S_OK:
2092 break;
2093 case MUX_S_PERMISSION_DENIED:
2094 e = buffer_get_string(&m, NULL);
2095 fatal("Master refused stop listening request: %s", e);
2096 case MUX_S_FAILURE:
2097 e = buffer_get_string(&m, NULL);
2098 fatal("%s: stop listening request failed: %s", __func__, e);
2099 default:
2100 fatal("%s: unexpected response from master 0x%08x",
2101 __func__, type);
2102 }
2103 buffer_free(&m);
2104 muxclient_request_id++;
2105 }
2106
2107 /* Multiplex client main loop. */
2108 void
2109 muxclient(const char *path)
2110 {
2111 struct sockaddr_un addr;
2112 socklen_t sun_len;
2113 int sock;
2114 u_int pid;
2115
2116 if (muxclient_command == 0) {
2117 if (options.stdio_forward_host != NULL)
2118 muxclient_command = SSHMUX_COMMAND_STDIO_FWD;
2119 else
2120 muxclient_command = SSHMUX_COMMAND_OPEN;
2121 }
2122
2123 switch (options.control_master) {
2124 case SSHCTL_MASTER_AUTO:
2125 case SSHCTL_MASTER_AUTO_ASK:
2126 debug("auto-mux: Trying existing master");
2127 /* FALLTHROUGH */
2128 case SSHCTL_MASTER_NO:
2129 break;
2130 default:
2131 return;
2132 }
2133
2134 memset(&addr, '\0', sizeof(addr));
2135 addr.sun_family = AF_UNIX;
2136 sun_len = offsetof(struct sockaddr_un, sun_path) +
2137 strlen(path) + 1;
2138
2139 if (strlcpy(addr.sun_path, path,
2140 sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
2141 fatal("ControlPath too long");
2142
2143 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
2144 fatal("%s socket(): %s", __func__, strerror(errno));
2145
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:
2150 break;
2151 default:
2152 fatal("Control socket connect(%.100s): %s", path,
2153 strerror(errno));
2154 }
2155 if (errno == ECONNREFUSED &&
2156 options.control_master != SSHCTL_MASTER_NO) {
2157 debug("Stale control socket %.100s, unlinking", path);
2158 unlink(path);
2159 } else if (errno == ENOENT) {
2160 debug("Control socket \"%.100s\" does not exist", path);
2161 } else {
2162 error("Control socket connect(%.100s): %s", path,
2163 strerror(errno));
2164 }
2165 close(sock);
2166 return;
2167 }
2168 set_nonblock(sock);
2169
2170 if (mux_client_hello_exchange(sock) != 0) {
2171 error("%s: master hello exchange failed", __func__);
2172 close(sock);
2173 return;
2174 }
2175
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);
2181 exit(0);
2182 case SSHMUX_COMMAND_TERMINATE:
2183 mux_client_request_terminate(sock);
2184 fprintf(stderr, "Exit request sent.\r\n");
2185 exit(0);
2186 case SSHMUX_COMMAND_FORWARD:
2187 if (mux_client_forwards(sock, 0) != 0)
2188 fatal("%s: master forward request failed", __func__);
2189 exit(0);
2190 case SSHMUX_COMMAND_OPEN:
2191 if (mux_client_forwards(sock, 0) != 0) {
2192 error("%s: master forward request failed", __func__);
2193 return;
2194 }
2195 mux_client_request_session(sock);
2196 return;
2197 case SSHMUX_COMMAND_STDIO_FWD:
2198 mux_client_request_stdio_fwd(sock);
2199 exit(0);
2200 case SSHMUX_COMMAND_STOP:
2201 mux_client_request_stop_listening(sock);
2202 fprintf(stderr, "Stop listening request sent.\r\n");
2203 exit(0);
2204 case SSHMUX_COMMAND_CANCEL_FWD:
2205 if (mux_client_forwards(sock, 1) != 0)
2206 error("%s: master cancel forward request failed",
2207 __func__);
2208 exit(0);
2209 default:
2210 fatal("unrecognised muxclient_command %d", muxclient_command);
2211 }
2212 }
DragonFly BSD