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libc/_collate_lookup: Fix segfault seen on ISO-8859-5 locales
[dragonfly.git] / crypto / openssh / mux.c
blob48f7a050fd6b153069df2455f754c760dbe2b3e1
1 /* $OpenBSD: mux.c,v 1.48 2014/07/17 07:22:19 djm 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/param.h>
37 #include <sys/stat.h>
38 #include <sys/socket.h>
39 #include <sys/un.h>
40
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <signal.h>
44 #include <stdarg.h>
45 #include <stddef.h>
46 #include <stdlib.h>
47 #include <stdio.h>
48 #include <string.h>
49 #include <unistd.h>
50 #ifdef HAVE_PATHS_H
51 #include <paths.h>
52 #endif
53
54 #ifdef HAVE_POLL_H
55 #include <poll.h>
56 #else
57 # ifdef HAVE_SYS_POLL_H
58 # include <sys/poll.h>
59 # endif
60 #endif
61
62 #ifdef HAVE_UTIL_H
63 # include <util.h>
64 #endif
65
66 #include "openbsd-compat/sys-queue.h"
67 #include "xmalloc.h"
68 #include "log.h"
69 #include "ssh.h"
70 #include "ssh2.h"
71 #include "pathnames.h"
72 #include "misc.h"
73 #include "match.h"
74 #include "buffer.h"
75 #include "channels.h"
76 #include "msg.h"
77 #include "packet.h"
78 #include "monitor_fdpass.h"
79 #include "sshpty.h"
80 #include "key.h"
81 #include "readconf.h"
82 #include "clientloop.h"
83
84 /* from ssh.c */
85 extern int tty_flag;
86 extern Options options;
87 extern int stdin_null_flag;
88 extern char *host;
89 extern int subsystem_flag;
90 extern Buffer command;
91 extern volatile sig_atomic_t quit_pending;
92 extern char *stdio_forward_host;
93 extern int stdio_forward_port;
94
95 /* Context for session open confirmation callback */
96 struct mux_session_confirm_ctx {
97 u_int want_tty;
98 u_int want_subsys;
99 u_int want_x_fwd;
100 u_int want_agent_fwd;
101 Buffer cmd;
102 char *term;
103 struct termios tio;
104 char **env;
105 u_int rid;
106 };
107
108 /* Context for stdio fwd open confirmation callback */
109 struct mux_stdio_confirm_ctx {
110 u_int rid;
111 };
112
113 /* Context for global channel callback */
114 struct mux_channel_confirm_ctx {
115 u_int cid; /* channel id */
116 u_int rid; /* request id */
117 int fid; /* forward id */
118 };
119
120 /* fd to control socket */
121 int muxserver_sock = -1;
122
123 /* client request id */
124 u_int muxclient_request_id = 0;
125
126 /* Multiplexing control command */
127 u_int muxclient_command = 0;
128
129 /* Set when signalled. */
130 static volatile sig_atomic_t muxclient_terminate = 0;
131
132 /* PID of multiplex server */
133 static u_int muxserver_pid = 0;
134
135 static Channel *mux_listener_channel = NULL;
136
137 struct mux_master_state {
138 int hello_rcvd;
139 };
140
141 /* mux protocol messages */
142 #define MUX_MSG_HELLO 0x00000001
143 #define MUX_C_NEW_SESSION 0x10000002
144 #define MUX_C_ALIVE_CHECK 0x10000004
145 #define MUX_C_TERMINATE 0x10000005
146 #define MUX_C_OPEN_FWD 0x10000006
147 #define MUX_C_CLOSE_FWD 0x10000007
148 #define MUX_C_NEW_STDIO_FWD 0x10000008
149 #define MUX_C_STOP_LISTENING 0x10000009
150 #define MUX_S_OK 0x80000001
151 #define MUX_S_PERMISSION_DENIED 0x80000002
152 #define MUX_S_FAILURE 0x80000003
153 #define MUX_S_EXIT_MESSAGE 0x80000004
154 #define MUX_S_ALIVE 0x80000005
155 #define MUX_S_SESSION_OPENED 0x80000006
156 #define MUX_S_REMOTE_PORT 0x80000007
157 #define MUX_S_TTY_ALLOC_FAIL 0x80000008
158
159 /* type codes for MUX_C_OPEN_FWD and MUX_C_CLOSE_FWD */
160 #define MUX_FWD_LOCAL 1
161 #define MUX_FWD_REMOTE 2
162 #define MUX_FWD_DYNAMIC 3
163
164 static void mux_session_confirm(int, int, void *);
165 static void mux_stdio_confirm(int, int, void *);
166
167 static int process_mux_master_hello(u_int, Channel *, Buffer *, Buffer *);
168 static int process_mux_new_session(u_int, Channel *, Buffer *, Buffer *);
169 static int process_mux_alive_check(u_int, Channel *, Buffer *, Buffer *);
170 static int process_mux_terminate(u_int, Channel *, Buffer *, Buffer *);
171 static int process_mux_open_fwd(u_int, Channel *, Buffer *, Buffer *);
172 static int process_mux_close_fwd(u_int, Channel *, Buffer *, Buffer *);
173 static int process_mux_stdio_fwd(u_int, Channel *, Buffer *, Buffer *);
174 static int process_mux_stop_listening(u_int, Channel *, Buffer *, Buffer *);
175
176 static const struct {
177 u_int type;
178 int (*handler)(u_int, Channel *, Buffer *, Buffer *);
179 } mux_master_handlers[] = {
180 { MUX_MSG_HELLO, process_mux_master_hello },
181 { MUX_C_NEW_SESSION, process_mux_new_session },
182 { MUX_C_ALIVE_CHECK, process_mux_alive_check },
183 { MUX_C_TERMINATE, process_mux_terminate },
184 { MUX_C_OPEN_FWD, process_mux_open_fwd },
185 { MUX_C_CLOSE_FWD, process_mux_close_fwd },
186 { MUX_C_NEW_STDIO_FWD, process_mux_stdio_fwd },
187 { MUX_C_STOP_LISTENING, process_mux_stop_listening },
188 { 0, NULL }
189 };
190
191 /* Cleanup callback fired on closure of mux slave _session_ channel */
192 /* ARGSUSED */
193 static void
194 mux_master_session_cleanup_cb(int cid, void *unused)
195 {
196 Channel *cc, *c = channel_by_id(cid);
197
198 debug3("%s: entering for channel %d", __func__, cid);
199 if (c == NULL)
200 fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
201 if (c->ctl_chan != -1) {
202 if ((cc = channel_by_id(c->ctl_chan)) == NULL)
203 fatal("%s: channel %d missing control channel %d",
204 __func__, c->self, c->ctl_chan);
205 c->ctl_chan = -1;
206 cc->remote_id = -1;
207 chan_rcvd_oclose(cc);
208 }
209 channel_cancel_cleanup(c->self);
210 }
211
212 /* Cleanup callback fired on closure of mux slave _control_ channel */
213 /* ARGSUSED */
214 static void
215 mux_master_control_cleanup_cb(int cid, void *unused)
216 {
217 Channel *sc, *c = channel_by_id(cid);
218
219 debug3("%s: entering for channel %d", __func__, cid);
220 if (c == NULL)
221 fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
222 if (c->remote_id != -1) {
223 if ((sc = channel_by_id(c->remote_id)) == NULL)
224 fatal("%s: channel %d missing session channel %d",
225 __func__, c->self, c->remote_id);
226 c->remote_id = -1;
227 sc->ctl_chan = -1;
228 if (sc->type != SSH_CHANNEL_OPEN &&
229 sc->type != SSH_CHANNEL_OPENING) {
230 debug2("%s: channel %d: not open", __func__, sc->self);
231 chan_mark_dead(sc);
232 } else {
233 if (sc->istate == CHAN_INPUT_OPEN)
234 chan_read_failed(sc);
235 if (sc->ostate == CHAN_OUTPUT_OPEN)
236 chan_write_failed(sc);
237 }
238 }
239 channel_cancel_cleanup(c->self);
240 }
241
242 /* Check mux client environment variables before passing them to mux master. */
243 static int
244 env_permitted(char *env)
245 {
246 int i, ret;
247 char name[1024], *cp;
248
249 if ((cp = strchr(env, '=')) == NULL || cp == env)
250 return 0;
251 ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
252 if (ret <= 0 || (size_t)ret >= sizeof(name)) {
253 error("env_permitted: name '%.100s...' too long", env);
254 return 0;
255 }
256
257 for (i = 0; i < options.num_send_env; i++)
258 if (match_pattern(name, options.send_env[i]))
259 return 1;
260
261 return 0;
262 }
263
264 /* Mux master protocol message handlers */
265
266 static int
267 process_mux_master_hello(u_int rid, Channel *c, Buffer *m, Buffer *r)
268 {
269 u_int ver;
270 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
271
272 if (state == NULL)
273 fatal("%s: channel %d: c->mux_ctx == NULL", __func__, c->self);
274 if (state->hello_rcvd) {
275 error("%s: HELLO received twice", __func__);
276 return -1;
277 }
278 if (buffer_get_int_ret(&ver, m) != 0) {
279 malf:
280 error("%s: malformed message", __func__);
281 return -1;
282 }
283 if (ver != SSHMUX_VER) {
284 error("Unsupported multiplexing protocol version %d "
285 "(expected %d)", ver, SSHMUX_VER);
286 return -1;
287 }
288 debug2("%s: channel %d slave version %u", __func__, c->self, ver);
289
290 /* No extensions are presently defined */
291 while (buffer_len(m) > 0) {
292 char *name = buffer_get_string_ret(m, NULL);
293 char *value = buffer_get_string_ret(m, NULL);
294
295 if (name == NULL || value == NULL) {
296 free(name);
297 free(value);
298 goto malf;
299 }
300 debug2("Unrecognised slave extension \"%s\"", name);
301 free(name);
302 free(value);
303 }
304 state->hello_rcvd = 1;
305 return 0;
306 }
307
308 static int
309 process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r)
310 {
311 Channel *nc;
312 struct mux_session_confirm_ctx *cctx;
313 char *reserved, *cmd, *cp;
314 u_int i, j, len, env_len, escape_char, window, packetmax;
315 int new_fd[3];
316
317 /* Reply for SSHMUX_COMMAND_OPEN */
318 cctx = xcalloc(1, sizeof(*cctx));
319 cctx->term = NULL;
320 cctx->rid = rid;
321 cmd = reserved = NULL;
322 cctx->env = NULL;
323 env_len = 0;
324 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
325 buffer_get_int_ret(&cctx->want_tty, m) != 0 ||
326 buffer_get_int_ret(&cctx->want_x_fwd, m) != 0 ||
327 buffer_get_int_ret(&cctx->want_agent_fwd, m) != 0 ||
328 buffer_get_int_ret(&cctx->want_subsys, m) != 0 ||
329 buffer_get_int_ret(&escape_char, m) != 0 ||
330 (cctx->term = buffer_get_string_ret(m, &len)) == NULL ||
331 (cmd = buffer_get_string_ret(m, &len)) == NULL) {
332 malf:
333 free(cmd);
334 free(reserved);
335 for (j = 0; j < env_len; j++)
336 free(cctx->env[j]);
337 free(cctx->env);
338 free(cctx->term);
339 free(cctx);
340 error("%s: malformed message", __func__);
341 return -1;
342 }
343 free(reserved);
344 reserved = NULL;
345
346 while (buffer_len(m) > 0) {
347 #define MUX_MAX_ENV_VARS 4096
348 if ((cp = buffer_get_string_ret(m, &len)) == NULL)
349 goto malf;
350 if (!env_permitted(cp)) {
351 free(cp);
352 continue;
353 }
354 cctx->env = xrealloc(cctx->env, env_len + 2,
355 sizeof(*cctx->env));
356 cctx->env[env_len++] = cp;
357 cctx->env[env_len] = NULL;
358 if (env_len > MUX_MAX_ENV_VARS) {
359 error(">%d environment variables received, ignoring "
360 "additional", MUX_MAX_ENV_VARS);
361 break;
362 }
363 }
364
365 debug2("%s: channel %d: request tty %d, X %d, agent %d, subsys %d, "
366 "term \"%s\", cmd \"%s\", env %u", __func__, c->self,
367 cctx->want_tty, cctx->want_x_fwd, cctx->want_agent_fwd,
368 cctx->want_subsys, cctx->term, cmd, env_len);
369
370 buffer_init(&cctx->cmd);
371 buffer_append(&cctx->cmd, cmd, strlen(cmd));
372 free(cmd);
373 cmd = NULL;
374
375 /* Gather fds from client */
376 for(i = 0; i < 3; i++) {
377 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
378 error("%s: failed to receive fd %d from slave",
379 __func__, i);
380 for (j = 0; j < i; j++)
381 close(new_fd[j]);
382 for (j = 0; j < env_len; j++)
383 free(cctx->env[j]);
384 free(cctx->env);
385 free(cctx->term);
386 buffer_free(&cctx->cmd);
387 free(cctx);
388
389 /* prepare reply */
390 buffer_put_int(r, MUX_S_FAILURE);
391 buffer_put_int(r, rid);
392 buffer_put_cstring(r,
393 "did not receive file descriptors");
394 return -1;
395 }
396 }
397
398 debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
399 new_fd[0], new_fd[1], new_fd[2]);
400
401 /* XXX support multiple child sessions in future */
402 if (c->remote_id != -1) {
403 debug2("%s: session already open", __func__);
404 /* prepare reply */
405 buffer_put_int(r, MUX_S_FAILURE);
406 buffer_put_int(r, rid);
407 buffer_put_cstring(r, "Multiple sessions not supported");
408 cleanup:
409 close(new_fd[0]);
410 close(new_fd[1]);
411 close(new_fd[2]);
412 free(cctx->term);
413 if (env_len != 0) {
414 for (i = 0; i < env_len; i++)
415 free(cctx->env[i]);
416 free(cctx->env);
417 }
418 buffer_free(&cctx->cmd);
419 free(cctx);
420 return 0;
421 }
422
423 if (options.control_master == SSHCTL_MASTER_ASK ||
424 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
425 if (!ask_permission("Allow shared connection to %s? ", host)) {
426 debug2("%s: session refused by user", __func__);
427 /* prepare reply */
428 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
429 buffer_put_int(r, rid);
430 buffer_put_cstring(r, "Permission denied");
431 goto cleanup;
432 }
433 }
434
435 /* Try to pick up ttymodes from client before it goes raw */
436 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
437 error("%s: tcgetattr: %s", __func__, strerror(errno));
438
439 /* enable nonblocking unless tty */
440 if (!isatty(new_fd[0]))
441 set_nonblock(new_fd[0]);
442 if (!isatty(new_fd[1]))
443 set_nonblock(new_fd[1]);
444 if (!isatty(new_fd[2]))
445 set_nonblock(new_fd[2]);
446
447 window = CHAN_SES_WINDOW_DEFAULT;
448 packetmax = CHAN_SES_PACKET_DEFAULT;
449 if (cctx->want_tty) {
450 window >>= 1;
451 packetmax >>= 1;
452 }
453
454 nc = channel_new("session", SSH_CHANNEL_OPENING,
455 new_fd[0], new_fd[1], new_fd[2], window, packetmax,
456 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
457
458 nc->ctl_chan = c->self; /* link session -> control channel */
459 c->remote_id = nc->self; /* link control -> session channel */
460
461 if (cctx->want_tty && escape_char != 0xffffffff) {
462 channel_register_filter(nc->self,
463 client_simple_escape_filter, NULL,
464 client_filter_cleanup,
465 client_new_escape_filter_ctx((int)escape_char));
466 }
467
468 debug2("%s: channel_new: %d linked to control channel %d",
469 __func__, nc->self, nc->ctl_chan);
470
471 channel_send_open(nc->self);
472 channel_register_open_confirm(nc->self, mux_session_confirm, cctx);
473 c->mux_pause = 1; /* stop handling messages until open_confirm done */
474 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
475
476 /* reply is deferred, sent by mux_session_confirm */
477 return 0;
478 }
479
480 static int
481 process_mux_alive_check(u_int rid, Channel *c, Buffer *m, Buffer *r)
482 {
483 debug2("%s: channel %d: alive check", __func__, c->self);
484
485 /* prepare reply */
486 buffer_put_int(r, MUX_S_ALIVE);
487 buffer_put_int(r, rid);
488 buffer_put_int(r, (u_int)getpid());
489
490 return 0;
491 }
492
493 static int
494 process_mux_terminate(u_int rid, Channel *c, Buffer *m, Buffer *r)
495 {
496 debug2("%s: channel %d: terminate request", __func__, c->self);
497
498 if (options.control_master == SSHCTL_MASTER_ASK ||
499 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
500 if (!ask_permission("Terminate shared connection to %s? ",
501 host)) {
502 debug2("%s: termination refused by user", __func__);
503 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
504 buffer_put_int(r, rid);
505 buffer_put_cstring(r, "Permission denied");
506 return 0;
507 }
508 }
509
510 quit_pending = 1;
511 buffer_put_int(r, MUX_S_OK);
512 buffer_put_int(r, rid);
513 /* XXX exit happens too soon - message never makes it to client */
514 return 0;
515 }
516
517 static char *
518 format_forward(u_int ftype, struct Forward *fwd)
519 {
520 char *ret;
521
522 switch (ftype) {
523 case MUX_FWD_LOCAL:
524 xasprintf(&ret, "local forward %.200s:%d -> %.200s:%d",
525 (fwd->listen_path != NULL) ? fwd->listen_path :
526 (fwd->listen_host == NULL) ?
527 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
528 fwd->listen_host, fwd->listen_port,
529 (fwd->connect_path != NULL) ? fwd->connect_path :
530 fwd->connect_host, fwd->connect_port);
531 break;
532 case MUX_FWD_DYNAMIC:
533 xasprintf(&ret, "dynamic forward %.200s:%d -> *",
534 (fwd->listen_host == NULL) ?
535 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
536 fwd->listen_host, fwd->listen_port);
537 break;
538 case MUX_FWD_REMOTE:
539 xasprintf(&ret, "remote forward %.200s:%d -> %.200s:%d",
540 (fwd->listen_path != NULL) ? fwd->listen_path :
541 (fwd->listen_host == NULL) ?
542 "LOCALHOST" : fwd->listen_host,
543 fwd->listen_port,
544 (fwd->connect_path != NULL) ? fwd->connect_path :
545 fwd->connect_host, fwd->connect_port);
546 break;
547 default:
548 fatal("%s: unknown forward type %u", __func__, ftype);
549 }
550 return ret;
551 }
552
553 static int
554 compare_host(const char *a, const char *b)
555 {
556 if (a == NULL && b == NULL)
557 return 1;
558 if (a == NULL || b == NULL)
559 return 0;
560 return strcmp(a, b) == 0;
561 }
562
563 static int
564 compare_forward(struct Forward *a, struct Forward *b)
565 {
566 if (!compare_host(a->listen_host, b->listen_host))
567 return 0;
568 if (!compare_host(a->listen_path, b->listen_path))
569 return 0;
570 if (a->listen_port != b->listen_port)
571 return 0;
572 if (!compare_host(a->connect_host, b->connect_host))
573 return 0;
574 if (!compare_host(a->connect_path, b->connect_path))
575 return 0;
576 if (a->connect_port != b->connect_port)
577 return 0;
578
579 return 1;
580 }
581
582 static void
583 mux_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
584 {
585 struct mux_channel_confirm_ctx *fctx = ctxt;
586 char *failmsg = NULL;
587 struct Forward *rfwd;
588 Channel *c;
589 Buffer out;
590
591 if ((c = channel_by_id(fctx->cid)) == NULL) {
592 /* no channel for reply */
593 error("%s: unknown channel", __func__);
594 return;
595 }
596 buffer_init(&out);
597 if (fctx->fid >= options.num_remote_forwards) {
598 xasprintf(&failmsg, "unknown forwarding id %d", fctx->fid);
599 goto fail;
600 }
601 rfwd = &options.remote_forwards[fctx->fid];
602 debug("%s: %s for: listen %d, connect %s:%d", __func__,
603 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
604 rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
605 rfwd->connect_host, rfwd->connect_port);
606 if (type == SSH2_MSG_REQUEST_SUCCESS) {
607 if (rfwd->listen_port == 0) {
608 rfwd->allocated_port = packet_get_int();
609 logit("Allocated port %u for mux remote forward"
610 " to %s:%d", rfwd->allocated_port,
611 rfwd->connect_host, rfwd->connect_port);
612 buffer_put_int(&out, MUX_S_REMOTE_PORT);
613 buffer_put_int(&out, fctx->rid);
614 buffer_put_int(&out, rfwd->allocated_port);
615 channel_update_permitted_opens(rfwd->handle,
616 rfwd->allocated_port);
617 } else {
618 buffer_put_int(&out, MUX_S_OK);
619 buffer_put_int(&out, fctx->rid);
620 }
621 goto out;
622 } else {
623 if (rfwd->listen_port == 0)
624 channel_update_permitted_opens(rfwd->handle, -1);
625 if (rfwd->listen_path != NULL)
626 xasprintf(&failmsg, "remote port forwarding failed for "
627 "listen path %s", rfwd->listen_path);
628 else
629 xasprintf(&failmsg, "remote port forwarding failed for "
630 "listen port %d", rfwd->listen_port);
631 }
632 fail:
633 error("%s: %s", __func__, failmsg);
634 buffer_put_int(&out, MUX_S_FAILURE);
635 buffer_put_int(&out, fctx->rid);
636 buffer_put_cstring(&out, failmsg);
637 free(failmsg);
638 out:
639 buffer_put_string(&c->output, buffer_ptr(&out), buffer_len(&out));
640 buffer_free(&out);
641 if (c->mux_pause <= 0)
642 fatal("%s: mux_pause %d", __func__, c->mux_pause);
643 c->mux_pause = 0; /* start processing messages again */
644 }
645
646 static int
647 process_mux_open_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
648 {
649 struct Forward fwd;
650 char *fwd_desc = NULL;
651 char *listen_addr, *connect_addr;
652 u_int ftype;
653 u_int lport, cport;
654 int i, ret = 0, freefwd = 1;
655
656 /* XXX - lport/cport check redundant */
657 if (buffer_get_int_ret(&ftype, m) != 0 ||
658 (listen_addr = buffer_get_string_ret(m, NULL)) == NULL ||
659 buffer_get_int_ret(&lport, m) != 0 ||
660 (connect_addr = buffer_get_string_ret(m, NULL)) == NULL ||
661 buffer_get_int_ret(&cport, m) != 0 ||
662 (lport != (u_int)PORT_STREAMLOCAL && lport > 65535) ||
663 (cport != (u_int)PORT_STREAMLOCAL && cport > 65535)) {
664 error("%s: malformed message", __func__);
665 ret = -1;
666 goto out;
667 }
668 if (*listen_addr == '\0') {
669 free(listen_addr);
670 listen_addr = NULL;
671 }
672 if (*connect_addr == '\0') {
673 free(connect_addr);
674 connect_addr = NULL;
675 }
676
677 memset(&fwd, 0, sizeof(fwd));
678 fwd.listen_port = lport;
679 if (fwd.listen_port == PORT_STREAMLOCAL)
680 fwd.listen_path = listen_addr;
681 else
682 fwd.listen_host = listen_addr;
683 fwd.connect_port = cport;
684 if (fwd.connect_port == PORT_STREAMLOCAL)
685 fwd.connect_path = connect_addr;
686 else
687 fwd.connect_host = connect_addr;
688
689 debug2("%s: channel %d: request %s", __func__, c->self,
690 (fwd_desc = format_forward(ftype, &fwd)));
691
692 if (ftype != MUX_FWD_LOCAL && ftype != MUX_FWD_REMOTE &&
693 ftype != MUX_FWD_DYNAMIC) {
694 logit("%s: invalid forwarding type %u", __func__, ftype);
695 invalid:
696 free(listen_addr);
697 free(connect_addr);
698 buffer_put_int(r, MUX_S_FAILURE);
699 buffer_put_int(r, rid);
700 buffer_put_cstring(r, "Invalid forwarding request");
701 return 0;
702 }
703 if (ftype == MUX_FWD_DYNAMIC && fwd.listen_path) {
704 logit("%s: streamlocal and dynamic forwards "
705 "are mutually exclusive", __func__);
706 goto invalid;
707 }
708 if (fwd.listen_port != PORT_STREAMLOCAL && fwd.listen_port >= 65536) {
709 logit("%s: invalid listen port %u", __func__,
710 fwd.listen_port);
711 goto invalid;
712 }
713 if ((fwd.connect_port != PORT_STREAMLOCAL && fwd.connect_port >= 65536)
714 || (ftype != MUX_FWD_DYNAMIC && ftype != MUX_FWD_REMOTE && fwd.connect_port == 0)) {
715 logit("%s: invalid connect port %u", __func__,
716 fwd.connect_port);
717 goto invalid;
718 }
719 if (ftype != MUX_FWD_DYNAMIC && fwd.connect_host == NULL && fwd.connect_path == NULL) {
720 logit("%s: missing connect host", __func__);
721 goto invalid;
722 }
723
724 /* Skip forwards that have already been requested */
725 switch (ftype) {
726 case MUX_FWD_LOCAL:
727 case MUX_FWD_DYNAMIC:
728 for (i = 0; i < options.num_local_forwards; i++) {
729 if (compare_forward(&fwd,
730 options.local_forwards + i)) {
731 exists:
732 debug2("%s: found existing forwarding",
733 __func__);
734 buffer_put_int(r, MUX_S_OK);
735 buffer_put_int(r, rid);
736 goto out;
737 }
738 }
739 break;
740 case MUX_FWD_REMOTE:
741 for (i = 0; i < options.num_remote_forwards; i++) {
742 if (compare_forward(&fwd,
743 options.remote_forwards + i)) {
744 if (fwd.listen_port != 0)
745 goto exists;
746 debug2("%s: found allocated port",
747 __func__);
748 buffer_put_int(r, MUX_S_REMOTE_PORT);
749 buffer_put_int(r, rid);
750 buffer_put_int(r,
751 options.remote_forwards[i].allocated_port);
752 goto out;
753 }
754 }
755 break;
756 }
757
758 if (options.control_master == SSHCTL_MASTER_ASK ||
759 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
760 if (!ask_permission("Open %s on %s?", fwd_desc, host)) {
761 debug2("%s: forwarding refused by user", __func__);
762 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
763 buffer_put_int(r, rid);
764 buffer_put_cstring(r, "Permission denied");
765 goto out;
766 }
767 }
768
769 if (ftype == MUX_FWD_LOCAL || ftype == MUX_FWD_DYNAMIC) {
770 if (!channel_setup_local_fwd_listener(&fwd,
771 &options.fwd_opts)) {
772 fail:
773 logit("slave-requested %s failed", fwd_desc);
774 buffer_put_int(r, MUX_S_FAILURE);
775 buffer_put_int(r, rid);
776 buffer_put_cstring(r, "Port forwarding failed");
777 goto out;
778 }
779 add_local_forward(&options, &fwd);
780 freefwd = 0;
781 } else {
782 struct mux_channel_confirm_ctx *fctx;
783
784 fwd.handle = channel_request_remote_forwarding(&fwd);
785 if (fwd.handle < 0)
786 goto fail;
787 add_remote_forward(&options, &fwd);
788 fctx = xcalloc(1, sizeof(*fctx));
789 fctx->cid = c->self;
790 fctx->rid = rid;
791 fctx->fid = options.num_remote_forwards - 1;
792 client_register_global_confirm(mux_confirm_remote_forward,
793 fctx);
794 freefwd = 0;
795 c->mux_pause = 1; /* wait for mux_confirm_remote_forward */
796 /* delayed reply in mux_confirm_remote_forward */
797 goto out;
798 }
799 buffer_put_int(r, MUX_S_OK);
800 buffer_put_int(r, rid);
801 out:
802 free(fwd_desc);
803 if (freefwd) {
804 free(fwd.listen_host);
805 free(fwd.listen_path);
806 free(fwd.connect_host);
807 free(fwd.connect_path);
808 }
809 return ret;
810 }
811
812 static int
813 process_mux_close_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
814 {
815 struct Forward fwd, *found_fwd;
816 char *fwd_desc = NULL;
817 const char *error_reason = NULL;
818 char *listen_addr = NULL, *connect_addr = NULL;
819 u_int ftype;
820 int i, ret = 0;
821 u_int lport, cport;
822
823 if (buffer_get_int_ret(&ftype, m) != 0 ||
824 (listen_addr = buffer_get_string_ret(m, NULL)) == NULL ||
825 buffer_get_int_ret(&lport, m) != 0 ||
826 (connect_addr = buffer_get_string_ret(m, NULL)) == NULL ||
827 buffer_get_int_ret(&cport, m) != 0 ||
828 (lport != (u_int)PORT_STREAMLOCAL && lport > 65535) ||
829 (cport != (u_int)PORT_STREAMLOCAL && cport > 65535)) {
830 error("%s: malformed message", __func__);
831 ret = -1;
832 goto out;
833 }
834
835 if (*listen_addr == '\0') {
836 free(listen_addr);
837 listen_addr = NULL;
838 }
839 if (*connect_addr == '\0') {
840 free(connect_addr);
841 connect_addr = NULL;
842 }
843
844 memset(&fwd, 0, sizeof(fwd));
845 fwd.listen_port = lport;
846 if (fwd.listen_port == PORT_STREAMLOCAL)
847 fwd.listen_path = listen_addr;
848 else
849 fwd.listen_host = listen_addr;
850 fwd.connect_port = cport;
851 if (fwd.connect_port == PORT_STREAMLOCAL)
852 fwd.connect_path = connect_addr;
853 else
854 fwd.connect_host = connect_addr;
855
856 debug2("%s: channel %d: request cancel %s", __func__, c->self,
857 (fwd_desc = format_forward(ftype, &fwd)));
858
859 /* make sure this has been requested */
860 found_fwd = NULL;
861 switch (ftype) {
862 case MUX_FWD_LOCAL:
863 case MUX_FWD_DYNAMIC:
864 for (i = 0; i < options.num_local_forwards; i++) {
865 if (compare_forward(&fwd,
866 options.local_forwards + i)) {
867 found_fwd = options.local_forwards + i;
868 break;
869 }
870 }
871 break;
872 case MUX_FWD_REMOTE:
873 for (i = 0; i < options.num_remote_forwards; i++) {
874 if (compare_forward(&fwd,
875 options.remote_forwards + i)) {
876 found_fwd = options.remote_forwards + i;
877 break;
878 }
879 }
880 break;
881 }
882
883 if (found_fwd == NULL)
884 error_reason = "port not forwarded";
885 else if (ftype == MUX_FWD_REMOTE) {
886 /*
887 * This shouldn't fail unless we confused the host/port
888 * between options.remote_forwards and permitted_opens.
889 * However, for dynamic allocated listen ports we need
890 * to use the actual listen port.
891 */
892 if (channel_request_rforward_cancel(found_fwd) == -1)
893 error_reason = "port not in permitted opens";
894 } else { /* local and dynamic forwards */
895 /* Ditto */
896 if (channel_cancel_lport_listener(&fwd, fwd.connect_port,
897 &options.fwd_opts) == -1)
898 error_reason = "port not found";
899 }
900
901 if (error_reason == NULL) {
902 buffer_put_int(r, MUX_S_OK);
903 buffer_put_int(r, rid);
904
905 free(found_fwd->listen_host);
906 free(found_fwd->listen_path);
907 free(found_fwd->connect_host);
908 free(found_fwd->connect_path);
909 found_fwd->listen_host = found_fwd->connect_host = NULL;
910 found_fwd->listen_path = found_fwd->connect_path = NULL;
911 found_fwd->listen_port = found_fwd->connect_port = 0;
912 } else {
913 buffer_put_int(r, MUX_S_FAILURE);
914 buffer_put_int(r, rid);
915 buffer_put_cstring(r, error_reason);
916 }
917 out:
918 free(fwd_desc);
919 free(listen_addr);
920 free(connect_addr);
921
922 return ret;
923 }
924
925 static int
926 process_mux_stdio_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
927 {
928 Channel *nc;
929 char *reserved, *chost;
930 u_int cport, i, j;
931 int new_fd[2];
932 struct mux_stdio_confirm_ctx *cctx;
933
934 chost = reserved = NULL;
935 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
936 (chost = buffer_get_string_ret(m, NULL)) == NULL ||
937 buffer_get_int_ret(&cport, m) != 0) {
938 free(reserved);
939 free(chost);
940 error("%s: malformed message", __func__);
941 return -1;
942 }
943 free(reserved);
944
945 debug2("%s: channel %d: request stdio fwd to %s:%u",
946 __func__, c->self, chost, cport);
947
948 /* Gather fds from client */
949 for(i = 0; i < 2; i++) {
950 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
951 error("%s: failed to receive fd %d from slave",
952 __func__, i);
953 for (j = 0; j < i; j++)
954 close(new_fd[j]);
955 free(chost);
956
957 /* prepare reply */
958 buffer_put_int(r, MUX_S_FAILURE);
959 buffer_put_int(r, rid);
960 buffer_put_cstring(r,
961 "did not receive file descriptors");
962 return -1;
963 }
964 }
965
966 debug3("%s: got fds stdin %d, stdout %d", __func__,
967 new_fd[0], new_fd[1]);
968
969 /* XXX support multiple child sessions in future */
970 if (c->remote_id != -1) {
971 debug2("%s: session already open", __func__);
972 /* prepare reply */
973 buffer_put_int(r, MUX_S_FAILURE);
974 buffer_put_int(r, rid);
975 buffer_put_cstring(r, "Multiple sessions not supported");
976 cleanup:
977 close(new_fd[0]);
978 close(new_fd[1]);
979 free(chost);
980 return 0;
981 }
982
983 if (options.control_master == SSHCTL_MASTER_ASK ||
984 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
985 if (!ask_permission("Allow forward to %s:%u? ",
986 chost, cport)) {
987 debug2("%s: stdio fwd refused by user", __func__);
988 /* prepare reply */
989 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
990 buffer_put_int(r, rid);
991 buffer_put_cstring(r, "Permission denied");
992 goto cleanup;
993 }
994 }
995
996 /* enable nonblocking unless tty */
997 if (!isatty(new_fd[0]))
998 set_nonblock(new_fd[0]);
999 if (!isatty(new_fd[1]))
1000 set_nonblock(new_fd[1]);
1001
1002 nc = channel_connect_stdio_fwd(chost, cport, new_fd[0], new_fd[1]);
1003
1004 nc->ctl_chan = c->self; /* link session -> control channel */
1005 c->remote_id = nc->self; /* link control -> session channel */
1006
1007 debug2("%s: channel_new: %d linked to control channel %d",
1008 __func__, nc->self, nc->ctl_chan);
1009
1010 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
1011
1012 cctx = xcalloc(1, sizeof(*cctx));
1013 cctx->rid = rid;
1014 channel_register_open_confirm(nc->self, mux_stdio_confirm, cctx);
1015 c->mux_pause = 1; /* stop handling messages until open_confirm done */
1016
1017 /* reply is deferred, sent by mux_session_confirm */
1018 return 0;
1019 }
1020
1021 /* Callback on open confirmation in mux master for a mux stdio fwd session. */
1022 static void
1023 mux_stdio_confirm(int id, int success, void *arg)
1024 {
1025 struct mux_stdio_confirm_ctx *cctx = arg;
1026 Channel *c, *cc;
1027 Buffer reply;
1028
1029 if (cctx == NULL)
1030 fatal("%s: cctx == NULL", __func__);
1031 if ((c = channel_by_id(id)) == NULL)
1032 fatal("%s: no channel for id %d", __func__, id);
1033 if ((cc = channel_by_id(c->ctl_chan)) == NULL)
1034 fatal("%s: channel %d lacks control channel %d", __func__,
1035 id, c->ctl_chan);
1036
1037 if (!success) {
1038 debug3("%s: sending failure reply", __func__);
1039 /* prepare reply */
1040 buffer_init(&reply);
1041 buffer_put_int(&reply, MUX_S_FAILURE);
1042 buffer_put_int(&reply, cctx->rid);
1043 buffer_put_cstring(&reply, "Session open refused by peer");
1044 goto done;
1045 }
1046
1047 debug3("%s: sending success reply", __func__);
1048 /* prepare reply */
1049 buffer_init(&reply);
1050 buffer_put_int(&reply, MUX_S_SESSION_OPENED);
1051 buffer_put_int(&reply, cctx->rid);
1052 buffer_put_int(&reply, c->self);
1053
1054 done:
1055 /* Send reply */
1056 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
1057 buffer_free(&reply);
1058
1059 if (cc->mux_pause <= 0)
1060 fatal("%s: mux_pause %d", __func__, cc->mux_pause);
1061 cc->mux_pause = 0; /* start processing messages again */
1062 c->open_confirm_ctx = NULL;
1063 free(cctx);
1064 }
1065
1066 static int
1067 process_mux_stop_listening(u_int rid, Channel *c, Buffer *m, Buffer *r)
1068 {
1069 debug("%s: channel %d: stop listening", __func__, c->self);
1070
1071 if (options.control_master == SSHCTL_MASTER_ASK ||
1072 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
1073 if (!ask_permission("Disable further multiplexing on shared "
1074 "connection to %s? ", host)) {
1075 debug2("%s: stop listen refused by user", __func__);
1076 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
1077 buffer_put_int(r, rid);
1078 buffer_put_cstring(r, "Permission denied");
1079 return 0;
1080 }
1081 }
1082
1083 if (mux_listener_channel != NULL) {
1084 channel_free(mux_listener_channel);
1085 client_stop_mux();
1086 free(options.control_path);
1087 options.control_path = NULL;
1088 mux_listener_channel = NULL;
1089 muxserver_sock = -1;
1090 }
1091
1092 /* prepare reply */
1093 buffer_put_int(r, MUX_S_OK);
1094 buffer_put_int(r, rid);
1095
1096 return 0;
1097 }
1098
1099 /* Channel callbacks fired on read/write from mux slave fd */
1100 static int
1101 mux_master_read_cb(Channel *c)
1102 {
1103 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
1104 Buffer in, out;
1105 const u_char *ptr;
1106 u_int type, rid, have, i;
1107 int ret = -1;
1108
1109 /* Setup ctx and */
1110 if (c->mux_ctx == NULL) {
1111 state = xcalloc(1, sizeof(*state));
1112 c->mux_ctx = state;
1113 channel_register_cleanup(c->self,
1114 mux_master_control_cleanup_cb, 0);
1115
1116 /* Send hello */
1117 buffer_init(&out);
1118 buffer_put_int(&out, MUX_MSG_HELLO);
1119 buffer_put_int(&out, SSHMUX_VER);
1120 /* no extensions */
1121 buffer_put_string(&c->output, buffer_ptr(&out),
1122 buffer_len(&out));
1123 buffer_free(&out);
1124 debug3("%s: channel %d: hello sent", __func__, c->self);
1125 return 0;
1126 }
1127
1128 buffer_init(&in);
1129 buffer_init(&out);
1130
1131 /* Channel code ensures that we receive whole packets */
1132 if ((ptr = buffer_get_string_ptr_ret(&c->input, &have)) == NULL) {
1133 malf:
1134 error("%s: malformed message", __func__);
1135 goto out;
1136 }
1137 buffer_append(&in, ptr, have);
1138
1139 if (buffer_get_int_ret(&type, &in) != 0)
1140 goto malf;
1141 debug3("%s: channel %d packet type 0x%08x len %u",
1142 __func__, c->self, type, buffer_len(&in));
1143
1144 if (type == MUX_MSG_HELLO)
1145 rid = 0;
1146 else {
1147 if (!state->hello_rcvd) {
1148 error("%s: expected MUX_MSG_HELLO(0x%08x), "
1149 "received 0x%08x", __func__, MUX_MSG_HELLO, type);
1150 goto out;
1151 }
1152 if (buffer_get_int_ret(&rid, &in) != 0)
1153 goto malf;
1154 }
1155
1156 for (i = 0; mux_master_handlers[i].handler != NULL; i++) {
1157 if (type == mux_master_handlers[i].type) {
1158 ret = mux_master_handlers[i].handler(rid, c, &in, &out);
1159 break;
1160 }
1161 }
1162 if (mux_master_handlers[i].handler == NULL) {
1163 error("%s: unsupported mux message 0x%08x", __func__, type);
1164 buffer_put_int(&out, MUX_S_FAILURE);
1165 buffer_put_int(&out, rid);
1166 buffer_put_cstring(&out, "unsupported request");
1167 ret = 0;
1168 }
1169 /* Enqueue reply packet */
1170 if (buffer_len(&out) != 0) {
1171 buffer_put_string(&c->output, buffer_ptr(&out),
1172 buffer_len(&out));
1173 }
1174 out:
1175 buffer_free(&in);
1176 buffer_free(&out);
1177 return ret;
1178 }
1179
1180 void
1181 mux_exit_message(Channel *c, int exitval)
1182 {
1183 Buffer m;
1184 Channel *mux_chan;
1185
1186 debug3("%s: channel %d: exit message, exitval %d", __func__, c->self,
1187 exitval);
1188
1189 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL)
1190 fatal("%s: channel %d missing mux channel %d",
1191 __func__, c->self, c->ctl_chan);
1192
1193 /* Append exit message packet to control socket output queue */
1194 buffer_init(&m);
1195 buffer_put_int(&m, MUX_S_EXIT_MESSAGE);
1196 buffer_put_int(&m, c->self);
1197 buffer_put_int(&m, exitval);
1198
1199 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1200 buffer_free(&m);
1201 }
1202
1203 void
1204 mux_tty_alloc_failed(Channel *c)
1205 {
1206 Buffer m;
1207 Channel *mux_chan;
1208
1209 debug3("%s: channel %d: TTY alloc failed", __func__, c->self);
1210
1211 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL)
1212 fatal("%s: channel %d missing mux channel %d",
1213 __func__, c->self, c->ctl_chan);
1214
1215 /* Append exit message packet to control socket output queue */
1216 buffer_init(&m);
1217 buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL);
1218 buffer_put_int(&m, c->self);
1219
1220 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1221 buffer_free(&m);
1222 }
1223
1224 /* Prepare a mux master to listen on a Unix domain socket. */
1225 void
1226 muxserver_listen(void)
1227 {
1228 mode_t old_umask;
1229 char *orig_control_path = options.control_path;
1230 char rbuf[16+1];
1231 u_int i, r;
1232 int oerrno;
1233
1234 if (options.control_path == NULL ||
1235 options.control_master == SSHCTL_MASTER_NO)
1236 return;
1237
1238 debug("setting up multiplex master socket");
1239
1240 /*
1241 * Use a temporary path before listen so we can pseudo-atomically
1242 * establish the listening socket in its final location to avoid
1243 * other processes racing in between bind() and listen() and hitting
1244 * an unready socket.
1245 */
1246 for (i = 0; i < sizeof(rbuf) - 1; i++) {
1247 r = arc4random_uniform(26+26+10);
1248 rbuf[i] = (r < 26) ? 'a' + r :
1249 (r < 26*2) ? 'A' + r - 26 :
1250 '0' + r - 26 - 26;
1251 }
1252 rbuf[sizeof(rbuf) - 1] = '\0';
1253 options.control_path = NULL;
1254 xasprintf(&options.control_path, "%s.%s", orig_control_path, rbuf);
1255 debug3("%s: temporary control path %s", __func__, options.control_path);
1256
1257 old_umask = umask(0177);
1258 muxserver_sock = unix_listener(options.control_path, 64, 0);
1259 oerrno = errno;
1260 umask(old_umask);
1261 if (muxserver_sock < 0) {
1262 if (oerrno == EINVAL || oerrno == EADDRINUSE) {
1263 error("ControlSocket %s already exists, "
1264 "disabling multiplexing", options.control_path);
1265 disable_mux_master:
1266 if (muxserver_sock != -1) {
1267 close(muxserver_sock);
1268 muxserver_sock = -1;
1269 }
1270 free(orig_control_path);
1271 free(options.control_path);
1272 options.control_path = NULL;
1273 options.control_master = SSHCTL_MASTER_NO;
1274 return;
1275 } else {
1276 /* unix_listener() logs the error */
1277 cleanup_exit(255);
1278 }
1279 }
1280
1281 /* Now atomically "move" the mux socket into position */
1282 if (link(options.control_path, orig_control_path) != 0) {
1283 if (errno != EEXIST) {
1284 fatal("%s: link mux listener %s => %s: %s", __func__,
1285 options.control_path, orig_control_path,
1286 strerror(errno));
1287 }
1288 error("ControlSocket %s already exists, disabling multiplexing",
1289 orig_control_path);
1290 unlink(options.control_path);
1291 goto disable_mux_master;
1292 }
1293 unlink(options.control_path);
1294 free(options.control_path);
1295 options.control_path = orig_control_path;
1296
1297 set_nonblock(muxserver_sock);
1298
1299 mux_listener_channel = channel_new("mux listener",
1300 SSH_CHANNEL_MUX_LISTENER, muxserver_sock, muxserver_sock, -1,
1301 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1302 0, options.control_path, 1);
1303 mux_listener_channel->mux_rcb = mux_master_read_cb;
1304 debug3("%s: mux listener channel %d fd %d", __func__,
1305 mux_listener_channel->self, mux_listener_channel->sock);
1306 }
1307
1308 /* Callback on open confirmation in mux master for a mux client session. */
1309 static void
1310 mux_session_confirm(int id, int success, void *arg)
1311 {
1312 struct mux_session_confirm_ctx *cctx = arg;
1313 const char *display;
1314 Channel *c, *cc;
1315 int i;
1316 Buffer reply;
1317
1318 if (cctx == NULL)
1319 fatal("%s: cctx == NULL", __func__);
1320 if ((c = channel_by_id(id)) == NULL)
1321 fatal("%s: no channel for id %d", __func__, id);
1322 if ((cc = channel_by_id(c->ctl_chan)) == NULL)
1323 fatal("%s: channel %d lacks control channel %d", __func__,
1324 id, c->ctl_chan);
1325
1326 if (!success) {
1327 debug3("%s: sending failure reply", __func__);
1328 /* prepare reply */
1329 buffer_init(&reply);
1330 buffer_put_int(&reply, MUX_S_FAILURE);
1331 buffer_put_int(&reply, cctx->rid);
1332 buffer_put_cstring(&reply, "Session open refused by peer");
1333 goto done;
1334 }
1335
1336 display = getenv("DISPLAY");
1337 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
1338 char *proto, *data;
1339
1340 /* Get reasonable local authentication information. */
1341 client_x11_get_proto(display, options.xauth_location,
1342 options.forward_x11_trusted, options.forward_x11_timeout,
1343 &proto, &data);
1344 /* Request forwarding with authentication spoofing. */
1345 debug("Requesting X11 forwarding with authentication "
1346 "spoofing.");
1347 x11_request_forwarding_with_spoofing(id, display, proto,
1348 data, 1);
1349 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
1350 /* XXX exit_on_forward_failure */
1351 }
1352
1353 if (cctx->want_agent_fwd && options.forward_agent) {
1354 debug("Requesting authentication agent forwarding.");
1355 channel_request_start(id, "auth-agent-req@openssh.com", 0);
1356 packet_send();
1357 }
1358
1359 client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
1360 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env);
1361
1362 debug3("%s: sending success reply", __func__);
1363 /* prepare reply */
1364 buffer_init(&reply);
1365 buffer_put_int(&reply, MUX_S_SESSION_OPENED);
1366 buffer_put_int(&reply, cctx->rid);
1367 buffer_put_int(&reply, c->self);
1368
1369 done:
1370 /* Send reply */
1371 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
1372 buffer_free(&reply);
1373
1374 if (cc->mux_pause <= 0)
1375 fatal("%s: mux_pause %d", __func__, cc->mux_pause);
1376 cc->mux_pause = 0; /* start processing messages again */
1377 c->open_confirm_ctx = NULL;
1378 buffer_free(&cctx->cmd);
1379 free(cctx->term);
1380 if (cctx->env != NULL) {
1381 for (i = 0; cctx->env[i] != NULL; i++)
1382 free(cctx->env[i]);
1383 free(cctx->env);
1384 }
1385 free(cctx);
1386 }
1387
1388 /* ** Multiplexing client support */
1389
1390 /* Exit signal handler */
1391 static void
1392 control_client_sighandler(int signo)
1393 {
1394 muxclient_terminate = signo;
1395 }
1396
1397 /*
1398 * Relay signal handler - used to pass some signals from mux client to
1399 * mux master.
1400 */
1401 static void
1402 control_client_sigrelay(int signo)
1403 {
1404 int save_errno = errno;
1405
1406 if (muxserver_pid > 1)
1407 kill(muxserver_pid, signo);
1408
1409 errno = save_errno;
1410 }
1411
1412 static int
1413 mux_client_read(int fd, Buffer *b, u_int need)
1414 {
1415 u_int have;
1416 ssize_t len;
1417 u_char *p;
1418 struct pollfd pfd;
1419
1420 pfd.fd = fd;
1421 pfd.events = POLLIN;
1422 p = buffer_append_space(b, need);
1423 for (have = 0; have < need; ) {
1424 if (muxclient_terminate) {
1425 errno = EINTR;
1426 return -1;
1427 }
1428 len = read(fd, p + have, need - have);
1429 if (len < 0) {
1430 switch (errno) {
1431 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1432 case EWOULDBLOCK:
1433 #endif
1434 case EAGAIN:
1435 (void)poll(&pfd, 1, -1);
1436 /* FALLTHROUGH */
1437 case EINTR:
1438 continue;
1439 default:
1440 return -1;
1441 }
1442 }
1443 if (len == 0) {
1444 errno = EPIPE;
1445 return -1;
1446 }
1447 have += (u_int)len;
1448 }
1449 return 0;
1450 }
1451
1452 static int
1453 mux_client_write_packet(int fd, Buffer *m)
1454 {
1455 Buffer queue;
1456 u_int have, need;
1457 int oerrno, len;
1458 u_char *ptr;
1459 struct pollfd pfd;
1460
1461 pfd.fd = fd;
1462 pfd.events = POLLOUT;
1463 buffer_init(&queue);
1464 buffer_put_string(&queue, buffer_ptr(m), buffer_len(m));
1465
1466 need = buffer_len(&queue);
1467 ptr = buffer_ptr(&queue);
1468
1469 for (have = 0; have < need; ) {
1470 if (muxclient_terminate) {
1471 buffer_free(&queue);
1472 errno = EINTR;
1473 return -1;
1474 }
1475 len = write(fd, ptr + have, need - have);
1476 if (len < 0) {
1477 switch (errno) {
1478 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1479 case EWOULDBLOCK:
1480 #endif
1481 case EAGAIN:
1482 (void)poll(&pfd, 1, -1);
1483 /* FALLTHROUGH */
1484 case EINTR:
1485 continue;
1486 default:
1487 oerrno = errno;
1488 buffer_free(&queue);
1489 errno = oerrno;
1490 return -1;
1491 }
1492 }
1493 if (len == 0) {
1494 buffer_free(&queue);
1495 errno = EPIPE;
1496 return -1;
1497 }
1498 have += (u_int)len;
1499 }
1500 buffer_free(&queue);
1501 return 0;
1502 }
1503
1504 static int
1505 mux_client_read_packet(int fd, Buffer *m)
1506 {
1507 Buffer queue;
1508 u_int need, have;
1509 const u_char *ptr;
1510 int oerrno;
1511
1512 buffer_init(&queue);
1513 if (mux_client_read(fd, &queue, 4) != 0) {
1514 if ((oerrno = errno) == EPIPE)
1515 debug3("%s: read header failed: %s", __func__,
1516 strerror(errno));
1517 buffer_free(&queue);
1518 errno = oerrno;
1519 return -1;
1520 }
1521 need = get_u32(buffer_ptr(&queue));
1522 if (mux_client_read(fd, &queue, need) != 0) {
1523 oerrno = errno;
1524 debug3("%s: read body failed: %s", __func__, strerror(errno));
1525 buffer_free(&queue);
1526 errno = oerrno;
1527 return -1;
1528 }
1529 ptr = buffer_get_string_ptr(&queue, &have);
1530 buffer_append(m, ptr, have);
1531 buffer_free(&queue);
1532 return 0;
1533 }
1534
1535 static int
1536 mux_client_hello_exchange(int fd)
1537 {
1538 Buffer m;
1539 u_int type, ver;
1540
1541 buffer_init(&m);
1542 buffer_put_int(&m, MUX_MSG_HELLO);
1543 buffer_put_int(&m, SSHMUX_VER);
1544 /* no extensions */
1545
1546 if (mux_client_write_packet(fd, &m) != 0)
1547 fatal("%s: write packet: %s", __func__, strerror(errno));
1548
1549 buffer_clear(&m);
1550
1551 /* Read their HELLO */
1552 if (mux_client_read_packet(fd, &m) != 0) {
1553 buffer_free(&m);
1554 return -1;
1555 }
1556
1557 type = buffer_get_int(&m);
1558 if (type != MUX_MSG_HELLO)
1559 fatal("%s: expected HELLO (%u) received %u",
1560 __func__, MUX_MSG_HELLO, type);
1561 ver = buffer_get_int(&m);
1562 if (ver != SSHMUX_VER)
1563 fatal("Unsupported multiplexing protocol version %d "
1564 "(expected %d)", ver, SSHMUX_VER);
1565 debug2("%s: master version %u", __func__, ver);
1566 /* No extensions are presently defined */
1567 while (buffer_len(&m) > 0) {
1568 char *name = buffer_get_string(&m, NULL);
1569 char *value = buffer_get_string(&m, NULL);
1570
1571 debug2("Unrecognised master extension \"%s\"", name);
1572 free(name);
1573 free(value);
1574 }
1575 buffer_free(&m);
1576 return 0;
1577 }
1578
1579 static u_int
1580 mux_client_request_alive(int fd)
1581 {
1582 Buffer m;
1583 char *e;
1584 u_int pid, type, rid;
1585
1586 debug3("%s: entering", __func__);
1587
1588 buffer_init(&m);
1589 buffer_put_int(&m, MUX_C_ALIVE_CHECK);
1590 buffer_put_int(&m, muxclient_request_id);
1591
1592 if (mux_client_write_packet(fd, &m) != 0)
1593 fatal("%s: write packet: %s", __func__, strerror(errno));
1594
1595 buffer_clear(&m);
1596
1597 /* Read their reply */
1598 if (mux_client_read_packet(fd, &m) != 0) {
1599 buffer_free(&m);
1600 return 0;
1601 }
1602
1603 type = buffer_get_int(&m);
1604 if (type != MUX_S_ALIVE) {
1605 e = buffer_get_string(&m, NULL);
1606 fatal("%s: master returned error: %s", __func__, e);
1607 }
1608
1609 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1610 fatal("%s: out of sequence reply: my id %u theirs %u",
1611 __func__, muxclient_request_id, rid);
1612 pid = buffer_get_int(&m);
1613 buffer_free(&m);
1614
1615 debug3("%s: done pid = %u", __func__, pid);
1616
1617 muxclient_request_id++;
1618
1619 return pid;
1620 }
1621
1622 static void
1623 mux_client_request_terminate(int fd)
1624 {
1625 Buffer m;
1626 char *e;
1627 u_int type, rid;
1628
1629 debug3("%s: entering", __func__);
1630
1631 buffer_init(&m);
1632 buffer_put_int(&m, MUX_C_TERMINATE);
1633 buffer_put_int(&m, muxclient_request_id);
1634
1635 if (mux_client_write_packet(fd, &m) != 0)
1636 fatal("%s: write packet: %s", __func__, strerror(errno));
1637
1638 buffer_clear(&m);
1639
1640 /* Read their reply */
1641 if (mux_client_read_packet(fd, &m) != 0) {
1642 /* Remote end exited already */
1643 if (errno == EPIPE) {
1644 buffer_free(&m);
1645 return;
1646 }
1647 fatal("%s: read from master failed: %s",
1648 __func__, strerror(errno));
1649 }
1650
1651 type = buffer_get_int(&m);
1652 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1653 fatal("%s: out of sequence reply: my id %u theirs %u",
1654 __func__, muxclient_request_id, rid);
1655 switch (type) {
1656 case MUX_S_OK:
1657 break;
1658 case MUX_S_PERMISSION_DENIED:
1659 e = buffer_get_string(&m, NULL);
1660 fatal("Master refused termination request: %s", e);
1661 case MUX_S_FAILURE:
1662 e = buffer_get_string(&m, NULL);
1663 fatal("%s: termination request failed: %s", __func__, e);
1664 default:
1665 fatal("%s: unexpected response from master 0x%08x",
1666 __func__, type);
1667 }
1668 buffer_free(&m);
1669 muxclient_request_id++;
1670 }
1671
1672 static int
1673 mux_client_forward(int fd, int cancel_flag, u_int ftype, struct Forward *fwd)
1674 {
1675 Buffer m;
1676 char *e, *fwd_desc;
1677 u_int type, rid;
1678
1679 fwd_desc = format_forward(ftype, fwd);
1680 debug("Requesting %s %s",
1681 cancel_flag ? "cancellation of" : "forwarding of", fwd_desc);
1682 free(fwd_desc);
1683
1684 buffer_init(&m);
1685 buffer_put_int(&m, cancel_flag ? MUX_C_CLOSE_FWD : MUX_C_OPEN_FWD);
1686 buffer_put_int(&m, muxclient_request_id);
1687 buffer_put_int(&m, ftype);
1688 if (fwd->listen_path != NULL) {
1689 buffer_put_cstring(&m, fwd->listen_path);
1690 } else {
1691 buffer_put_cstring(&m,
1692 fwd->listen_host == NULL ? "" : fwd->listen_host);
1693 }
1694 buffer_put_int(&m, fwd->listen_port);
1695 if (fwd->connect_path != NULL) {
1696 buffer_put_cstring(&m, fwd->connect_path);
1697 } else {
1698 buffer_put_cstring(&m,
1699 fwd->connect_host == NULL ? "" : fwd->connect_host);
1700 }
1701 buffer_put_int(&m, fwd->connect_port);
1702
1703 if (mux_client_write_packet(fd, &m) != 0)
1704 fatal("%s: write packet: %s", __func__, strerror(errno));
1705
1706 buffer_clear(&m);
1707
1708 /* Read their reply */
1709 if (mux_client_read_packet(fd, &m) != 0) {
1710 buffer_free(&m);
1711 return -1;
1712 }
1713
1714 type = buffer_get_int(&m);
1715 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1716 fatal("%s: out of sequence reply: my id %u theirs %u",
1717 __func__, muxclient_request_id, rid);
1718 switch (type) {
1719 case MUX_S_OK:
1720 break;
1721 case MUX_S_REMOTE_PORT:
1722 if (cancel_flag)
1723 fatal("%s: got MUX_S_REMOTE_PORT for cancel", __func__);
1724 fwd->allocated_port = buffer_get_int(&m);
1725 logit("Allocated port %u for remote forward to %s:%d",
1726 fwd->allocated_port,
1727 fwd->connect_host ? fwd->connect_host : "",
1728 fwd->connect_port);
1729 if (muxclient_command == SSHMUX_COMMAND_FORWARD)
1730 fprintf(stdout, "%u\n", fwd->allocated_port);
1731 break;
1732 case MUX_S_PERMISSION_DENIED:
1733 e = buffer_get_string(&m, NULL);
1734 buffer_free(&m);
1735 error("Master refused forwarding request: %s", e);
1736 return -1;
1737 case MUX_S_FAILURE:
1738 e = buffer_get_string(&m, NULL);
1739 buffer_free(&m);
1740 error("%s: forwarding request failed: %s", __func__, e);
1741 return -1;
1742 default:
1743 fatal("%s: unexpected response from master 0x%08x",
1744 __func__, type);
1745 }
1746 buffer_free(&m);
1747
1748 muxclient_request_id++;
1749 return 0;
1750 }
1751
1752 static int
1753 mux_client_forwards(int fd, int cancel_flag)
1754 {
1755 int i, ret = 0;
1756
1757 debug3("%s: %s forwardings: %d local, %d remote", __func__,
1758 cancel_flag ? "cancel" : "request",
1759 options.num_local_forwards, options.num_remote_forwards);
1760
1761 /* XXX ExitOnForwardingFailure */
1762 for (i = 0; i < options.num_local_forwards; i++) {
1763 if (mux_client_forward(fd, cancel_flag,
1764 options.local_forwards[i].connect_port == 0 ?
1765 MUX_FWD_DYNAMIC : MUX_FWD_LOCAL,
1766 options.local_forwards + i) != 0)
1767 ret = -1;
1768 }
1769 for (i = 0; i < options.num_remote_forwards; i++) {
1770 if (mux_client_forward(fd, cancel_flag, MUX_FWD_REMOTE,
1771 options.remote_forwards + i) != 0)
1772 ret = -1;
1773 }
1774 return ret;
1775 }
1776
1777 static int
1778 mux_client_request_session(int fd)
1779 {
1780 Buffer m;
1781 char *e, *term;
1782 u_int i, rid, sid, esid, exitval, type, exitval_seen;
1783 extern char **environ;
1784 int devnull, rawmode;
1785
1786 debug3("%s: entering", __func__);
1787
1788 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
1789 error("%s: master alive request failed", __func__);
1790 return -1;
1791 }
1792
1793 signal(SIGPIPE, SIG_IGN);
1794
1795 if (stdin_null_flag) {
1796 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1797 fatal("open(/dev/null): %s", strerror(errno));
1798 if (dup2(devnull, STDIN_FILENO) == -1)
1799 fatal("dup2: %s", strerror(errno));
1800 if (devnull > STDERR_FILENO)
1801 close(devnull);
1802 }
1803
1804 term = getenv("TERM");
1805
1806 buffer_init(&m);
1807 buffer_put_int(&m, MUX_C_NEW_SESSION);
1808 buffer_put_int(&m, muxclient_request_id);
1809 buffer_put_cstring(&m, ""); /* reserved */
1810 buffer_put_int(&m, tty_flag);
1811 buffer_put_int(&m, options.forward_x11);
1812 buffer_put_int(&m, options.forward_agent);
1813 buffer_put_int(&m, subsystem_flag);
1814 buffer_put_int(&m, options.escape_char == SSH_ESCAPECHAR_NONE ?
1815 0xffffffff : (u_int)options.escape_char);
1816 buffer_put_cstring(&m, term == NULL ? "" : term);
1817 buffer_put_string(&m, buffer_ptr(&command), buffer_len(&command));
1818
1819 if (options.num_send_env > 0 && environ != NULL) {
1820 /* Pass environment */
1821 for (i = 0; environ[i] != NULL; i++) {
1822 if (env_permitted(environ[i])) {
1823 buffer_put_cstring(&m, environ[i]);
1824 }
1825 }
1826 }
1827
1828 if (mux_client_write_packet(fd, &m) != 0)
1829 fatal("%s: write packet: %s", __func__, strerror(errno));
1830
1831 /* Send the stdio file descriptors */
1832 if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
1833 mm_send_fd(fd, STDOUT_FILENO) == -1 ||
1834 mm_send_fd(fd, STDERR_FILENO) == -1)
1835 fatal("%s: send fds failed", __func__);
1836
1837 debug3("%s: session request sent", __func__);
1838
1839 /* Read their reply */
1840 buffer_clear(&m);
1841 if (mux_client_read_packet(fd, &m) != 0) {
1842 error("%s: read from master failed: %s",
1843 __func__, strerror(errno));
1844 buffer_free(&m);
1845 return -1;
1846 }
1847
1848 type = buffer_get_int(&m);
1849 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1850 fatal("%s: out of sequence reply: my id %u theirs %u",
1851 __func__, muxclient_request_id, rid);
1852 switch (type) {
1853 case MUX_S_SESSION_OPENED:
1854 sid = buffer_get_int(&m);
1855 debug("%s: master session id: %u", __func__, sid);
1856 break;
1857 case MUX_S_PERMISSION_DENIED:
1858 e = buffer_get_string(&m, NULL);
1859 buffer_free(&m);
1860 error("Master refused session request: %s", e);
1861 return -1;
1862 case MUX_S_FAILURE:
1863 e = buffer_get_string(&m, NULL);
1864 buffer_free(&m);
1865 error("%s: session request failed: %s", __func__, e);
1866 return -1;
1867 default:
1868 buffer_free(&m);
1869 error("%s: unexpected response from master 0x%08x",
1870 __func__, type);
1871 return -1;
1872 }
1873 muxclient_request_id++;
1874
1875 signal(SIGHUP, control_client_sighandler);
1876 signal(SIGINT, control_client_sighandler);
1877 signal(SIGTERM, control_client_sighandler);
1878 signal(SIGWINCH, control_client_sigrelay);
1879
1880 rawmode = tty_flag;
1881 if (tty_flag)
1882 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1883
1884 /*
1885 * Stick around until the controlee closes the client_fd.
1886 * Before it does, it is expected to write an exit message.
1887 * This process must read the value and wait for the closure of
1888 * the client_fd; if this one closes early, the multiplex master will
1889 * terminate early too (possibly losing data).
1890 */
1891 for (exitval = 255, exitval_seen = 0;;) {
1892 buffer_clear(&m);
1893 if (mux_client_read_packet(fd, &m) != 0)
1894 break;
1895 type = buffer_get_int(&m);
1896 switch (type) {
1897 case MUX_S_TTY_ALLOC_FAIL:
1898 if ((esid = buffer_get_int(&m)) != sid)
1899 fatal("%s: tty alloc fail on unknown session: "
1900 "my id %u theirs %u",
1901 __func__, sid, esid);
1902 leave_raw_mode(options.request_tty ==
1903 REQUEST_TTY_FORCE);
1904 rawmode = 0;
1905 continue;
1906 case MUX_S_EXIT_MESSAGE:
1907 if ((esid = buffer_get_int(&m)) != sid)
1908 fatal("%s: exit on unknown session: "
1909 "my id %u theirs %u",
1910 __func__, sid, esid);
1911 if (exitval_seen)
1912 fatal("%s: exitval sent twice", __func__);
1913 exitval = buffer_get_int(&m);
1914 exitval_seen = 1;
1915 continue;
1916 default:
1917 e = buffer_get_string(&m, NULL);
1918 fatal("%s: master returned error: %s", __func__, e);
1919 }
1920 }
1921
1922 close(fd);
1923 if (rawmode)
1924 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1925
1926 if (muxclient_terminate) {
1927 debug2("Exiting on signal %d", muxclient_terminate);
1928 exitval = 255;
1929 } else if (!exitval_seen) {
1930 debug2("Control master terminated unexpectedly");
1931 exitval = 255;
1932 } else
1933 debug2("Received exit status from master %d", exitval);
1934
1935 if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
1936 fprintf(stderr, "Shared connection to %s closed.\r\n", host);
1937
1938 exit(exitval);
1939 }
1940
1941 static int
1942 mux_client_request_stdio_fwd(int fd)
1943 {
1944 Buffer m;
1945 char *e;
1946 u_int type, rid, sid;
1947 int devnull;
1948
1949 debug3("%s: entering", __func__);
1950
1951 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
1952 error("%s: master alive request failed", __func__);
1953 return -1;
1954 }
1955
1956 signal(SIGPIPE, SIG_IGN);
1957
1958 if (stdin_null_flag) {
1959 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1960 fatal("open(/dev/null): %s", strerror(errno));
1961 if (dup2(devnull, STDIN_FILENO) == -1)
1962 fatal("dup2: %s", strerror(errno));
1963 if (devnull > STDERR_FILENO)
1964 close(devnull);
1965 }
1966
1967 buffer_init(&m);
1968 buffer_put_int(&m, MUX_C_NEW_STDIO_FWD);
1969 buffer_put_int(&m, muxclient_request_id);
1970 buffer_put_cstring(&m, ""); /* reserved */
1971 buffer_put_cstring(&m, stdio_forward_host);
1972 buffer_put_int(&m, stdio_forward_port);
1973
1974 if (mux_client_write_packet(fd, &m) != 0)
1975 fatal("%s: write packet: %s", __func__, strerror(errno));
1976
1977 /* Send the stdio file descriptors */
1978 if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
1979 mm_send_fd(fd, STDOUT_FILENO) == -1)
1980 fatal("%s: send fds failed", __func__);
1981
1982 debug3("%s: stdio forward request sent", __func__);
1983
1984 /* Read their reply */
1985 buffer_clear(&m);
1986
1987 if (mux_client_read_packet(fd, &m) != 0) {
1988 error("%s: read from master failed: %s",
1989 __func__, strerror(errno));
1990 buffer_free(&m);
1991 return -1;
1992 }
1993
1994 type = buffer_get_int(&m);
1995 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1996 fatal("%s: out of sequence reply: my id %u theirs %u",
1997 __func__, muxclient_request_id, rid);
1998 switch (type) {
1999 case MUX_S_SESSION_OPENED:
2000 sid = buffer_get_int(&m);
2001 debug("%s: master session id: %u", __func__, sid);
2002 break;
2003 case MUX_S_PERMISSION_DENIED:
2004 e = buffer_get_string(&m, NULL);
2005 buffer_free(&m);
2006 fatal("Master refused stdio forwarding request: %s", e);
2007 case MUX_S_FAILURE:
2008 e = buffer_get_string(&m, NULL);
2009 buffer_free(&m);
2010 fatal("Stdio forwarding request failed: %s", e);
2011 default:
2012 buffer_free(&m);
2013 error("%s: unexpected response from master 0x%08x",
2014 __func__, type);
2015 return -1;
2016 }
2017 muxclient_request_id++;
2018
2019 signal(SIGHUP, control_client_sighandler);
2020 signal(SIGINT, control_client_sighandler);
2021 signal(SIGTERM, control_client_sighandler);
2022 signal(SIGWINCH, control_client_sigrelay);
2023
2024 /*
2025 * Stick around until the controlee closes the client_fd.
2026 */
2027 buffer_clear(&m);
2028 if (mux_client_read_packet(fd, &m) != 0) {
2029 if (errno == EPIPE ||
2030 (errno == EINTR && muxclient_terminate != 0))
2031 return 0;
2032 fatal("%s: mux_client_read_packet: %s",
2033 __func__, strerror(errno));
2034 }
2035 fatal("%s: master returned unexpected message %u", __func__, type);
2036 }
2037
2038 static void
2039 mux_client_request_stop_listening(int fd)
2040 {
2041 Buffer m;
2042 char *e;
2043 u_int type, rid;
2044
2045 debug3("%s: entering", __func__);
2046
2047 buffer_init(&m);
2048 buffer_put_int(&m, MUX_C_STOP_LISTENING);
2049 buffer_put_int(&m, muxclient_request_id);
2050
2051 if (mux_client_write_packet(fd, &m) != 0)
2052 fatal("%s: write packet: %s", __func__, strerror(errno));
2053
2054 buffer_clear(&m);
2055
2056 /* Read their reply */
2057 if (mux_client_read_packet(fd, &m) != 0)
2058 fatal("%s: read from master failed: %s",
2059 __func__, strerror(errno));
2060
2061 type = buffer_get_int(&m);
2062 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
2063 fatal("%s: out of sequence reply: my id %u theirs %u",
2064 __func__, muxclient_request_id, rid);
2065 switch (type) {
2066 case MUX_S_OK:
2067 break;
2068 case MUX_S_PERMISSION_DENIED:
2069 e = buffer_get_string(&m, NULL);
2070 fatal("Master refused stop listening request: %s", e);
2071 case MUX_S_FAILURE:
2072 e = buffer_get_string(&m, NULL);
2073 fatal("%s: stop listening request failed: %s", __func__, e);
2074 default:
2075 fatal("%s: unexpected response from master 0x%08x",
2076 __func__, type);
2077 }
2078 buffer_free(&m);
2079 muxclient_request_id++;
2080 }
2081
2082 /* Multiplex client main loop. */
2083 void
2084 muxclient(const char *path)
2085 {
2086 struct sockaddr_un addr;
2087 socklen_t sun_len;
2088 int sock;
2089 u_int pid;
2090
2091 if (muxclient_command == 0) {
2092 if (stdio_forward_host != NULL)
2093 muxclient_command = SSHMUX_COMMAND_STDIO_FWD;
2094 else
2095 muxclient_command = SSHMUX_COMMAND_OPEN;
2096 }
2097
2098 switch (options.control_master) {
2099 case SSHCTL_MASTER_AUTO:
2100 case SSHCTL_MASTER_AUTO_ASK:
2101 debug("auto-mux: Trying existing master");
2102 /* FALLTHROUGH */
2103 case SSHCTL_MASTER_NO:
2104 break;
2105 default:
2106 return;
2107 }
2108
2109 memset(&addr, '\0', sizeof(addr));
2110 addr.sun_family = AF_UNIX;
2111 sun_len = offsetof(struct sockaddr_un, sun_path) +
2112 strlen(path) + 1;
2113
2114 if (strlcpy(addr.sun_path, path,
2115 sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
2116 fatal("ControlPath too long");
2117
2118 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
2119 fatal("%s socket(): %s", __func__, strerror(errno));
2120
2121 if (connect(sock, (struct sockaddr *)&addr, sun_len) == -1) {
2122 switch (muxclient_command) {
2123 case SSHMUX_COMMAND_OPEN:
2124 case SSHMUX_COMMAND_STDIO_FWD:
2125 break;
2126 default:
2127 fatal("Control socket connect(%.100s): %s", path,
2128 strerror(errno));
2129 }
2130 if (errno == ECONNREFUSED &&
2131 options.control_master != SSHCTL_MASTER_NO) {
2132 debug("Stale control socket %.100s, unlinking", path);
2133 unlink(path);
2134 } else if (errno == ENOENT) {
2135 debug("Control socket \"%.100s\" does not exist", path);
2136 } else {
2137 error("Control socket connect(%.100s): %s", path,
2138 strerror(errno));
2139 }
2140 close(sock);
2141 return;
2142 }
2143 set_nonblock(sock);
2144
2145 if (mux_client_hello_exchange(sock) != 0) {
2146 error("%s: master hello exchange failed", __func__);
2147 close(sock);
2148 return;
2149 }
2150
2151 switch (muxclient_command) {
2152 case SSHMUX_COMMAND_ALIVE_CHECK:
2153 if ((pid = mux_client_request_alive(sock)) == 0)
2154 fatal("%s: master alive check failed", __func__);
2155 fprintf(stderr, "Master running (pid=%d)\r\n", pid);
2156 exit(0);
2157 case SSHMUX_COMMAND_TERMINATE:
2158 mux_client_request_terminate(sock);
2159 fprintf(stderr, "Exit request sent.\r\n");
2160 exit(0);
2161 case SSHMUX_COMMAND_FORWARD:
2162 if (mux_client_forwards(sock, 0) != 0)
2163 fatal("%s: master forward request failed", __func__);
2164 exit(0);
2165 case SSHMUX_COMMAND_OPEN:
2166 if (mux_client_forwards(sock, 0) != 0) {
2167 error("%s: master forward request failed", __func__);
2168 return;
2169 }
2170 mux_client_request_session(sock);
2171 return;
2172 case SSHMUX_COMMAND_STDIO_FWD:
2173 mux_client_request_stdio_fwd(sock);
2174 exit(0);
2175 case SSHMUX_COMMAND_STOP:
2176 mux_client_request_stop_listening(sock);
2177 fprintf(stderr, "Stop listening request sent.\r\n");
2178 exit(0);
2179 case SSHMUX_COMMAND_CANCEL_FWD:
2180 if (mux_client_forwards(sock, 1) != 0)
2181 error("%s: master cancel forward request failed",
2182 __func__);
2183 exit(0);
2184 default:
2185 fatal("unrecognised muxclient_command %d", muxclient_command);
2186 }
2187 }
DragonFly BSD