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mld6query(8): Rename mld6.c -> mld6query.c
[dragonfly.git] / crypto / openssh / mux.c
blob5ae4544100e2fb5cb95560ce033ec8e2d35ac2f2
1 /* $OpenBSD: mux.c,v 1.69 2017/09/20 05:19:00 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 #include "ssherr.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
93 /* Context for session open confirmation callback */
94 struct mux_session_confirm_ctx {
95 u_int want_tty;
96 u_int want_subsys;
97 u_int want_x_fwd;
98 u_int want_agent_fwd;
99 Buffer cmd;
100 char *term;
101 struct termios tio;
102 char **env;
103 u_int rid;
104 };
105
106 /* Context for stdio fwd open confirmation callback */
107 struct mux_stdio_confirm_ctx {
108 u_int rid;
109 };
110
111 /* Context for global channel callback */
112 struct mux_channel_confirm_ctx {
113 u_int cid; /* channel id */
114 u_int rid; /* request id */
115 int fid; /* forward id */
116 };
117
118 /* fd to control socket */
119 int muxserver_sock = -1;
120
121 /* client request id */
122 u_int muxclient_request_id = 0;
123
124 /* Multiplexing control command */
125 u_int muxclient_command = 0;
126
127 /* Set when signalled. */
128 static volatile sig_atomic_t muxclient_terminate = 0;
129
130 /* PID of multiplex server */
131 static u_int muxserver_pid = 0;
132
133 static Channel *mux_listener_channel = NULL;
134
135 struct mux_master_state {
136 int hello_rcvd;
137 };
138
139 /* mux protocol messages */
140 #define MUX_MSG_HELLO 0x00000001
141 #define MUX_C_NEW_SESSION 0x10000002
142 #define MUX_C_ALIVE_CHECK 0x10000004
143 #define MUX_C_TERMINATE 0x10000005
144 #define MUX_C_OPEN_FWD 0x10000006
145 #define MUX_C_CLOSE_FWD 0x10000007
146 #define MUX_C_NEW_STDIO_FWD 0x10000008
147 #define MUX_C_STOP_LISTENING 0x10000009
148 #define MUX_C_PROXY 0x1000000f
149 #define MUX_S_OK 0x80000001
150 #define MUX_S_PERMISSION_DENIED 0x80000002
151 #define MUX_S_FAILURE 0x80000003
152 #define MUX_S_EXIT_MESSAGE 0x80000004
153 #define MUX_S_ALIVE 0x80000005
154 #define MUX_S_SESSION_OPENED 0x80000006
155 #define MUX_S_REMOTE_PORT 0x80000007
156 #define MUX_S_TTY_ALLOC_FAIL 0x80000008
157 #define MUX_S_PROXY 0x8000000f
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(struct ssh *, int, int, void *);
165 static void mux_stdio_confirm(struct ssh *, int, int, void *);
166
167 static int process_mux_master_hello(struct ssh *, u_int,
168 Channel *, struct sshbuf *, struct sshbuf *);
169 static int process_mux_new_session(struct ssh *, u_int,
170 Channel *, struct sshbuf *, struct sshbuf *);
171 static int process_mux_alive_check(struct ssh *, u_int,
172 Channel *, struct sshbuf *, struct sshbuf *);
173 static int process_mux_terminate(struct ssh *, u_int,
174 Channel *, struct sshbuf *, struct sshbuf *);
175 static int process_mux_open_fwd(struct ssh *, u_int,
176 Channel *, struct sshbuf *, struct sshbuf *);
177 static int process_mux_close_fwd(struct ssh *, u_int,
178 Channel *, struct sshbuf *, struct sshbuf *);
179 static int process_mux_stdio_fwd(struct ssh *, u_int,
180 Channel *, struct sshbuf *, struct sshbuf *);
181 static int process_mux_stop_listening(struct ssh *, u_int,
182 Channel *, struct sshbuf *, struct sshbuf *);
183 static int process_mux_proxy(struct ssh *, u_int,
184 Channel *, struct sshbuf *, struct sshbuf *);
185
186 static const struct {
187 u_int type;
188 int (*handler)(struct ssh *, u_int, Channel *,
189 struct sshbuf *, struct sshbuf *);
190 } mux_master_handlers[] = {
191 { MUX_MSG_HELLO, process_mux_master_hello },
192 { MUX_C_NEW_SESSION, process_mux_new_session },
193 { MUX_C_ALIVE_CHECK, process_mux_alive_check },
194 { MUX_C_TERMINATE, process_mux_terminate },
195 { MUX_C_OPEN_FWD, process_mux_open_fwd },
196 { MUX_C_CLOSE_FWD, process_mux_close_fwd },
197 { MUX_C_NEW_STDIO_FWD, process_mux_stdio_fwd },
198 { MUX_C_STOP_LISTENING, process_mux_stop_listening },
199 { MUX_C_PROXY, process_mux_proxy },
200 { 0, NULL }
201 };
202
203 /* Cleanup callback fired on closure of mux slave _session_ channel */
204 /* ARGSUSED */
205 static void
206 mux_master_session_cleanup_cb(struct ssh *ssh, int cid, void *unused)
207 {
208 Channel *cc, *c = channel_by_id(ssh, cid);
209
210 debug3("%s: entering for channel %d", __func__, cid);
211 if (c == NULL)
212 fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
213 if (c->ctl_chan != -1) {
214 if ((cc = channel_by_id(ssh, c->ctl_chan)) == NULL)
215 fatal("%s: channel %d missing control channel %d",
216 __func__, c->self, c->ctl_chan);
217 c->ctl_chan = -1;
218 cc->remote_id = 0;
219 cc->have_remote_id = 0;
220 chan_rcvd_oclose(ssh, cc);
221 }
222 channel_cancel_cleanup(ssh, c->self);
223 }
224
225 /* Cleanup callback fired on closure of mux slave _control_ channel */
226 /* ARGSUSED */
227 static void
228 mux_master_control_cleanup_cb(struct ssh *ssh, int cid, void *unused)
229 {
230 Channel *sc, *c = channel_by_id(ssh, cid);
231
232 debug3("%s: entering for channel %d", __func__, cid);
233 if (c == NULL)
234 fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
235 if (c->have_remote_id) {
236 if ((sc = channel_by_id(ssh, c->remote_id)) == NULL)
237 fatal("%s: channel %d missing session channel %u",
238 __func__, c->self, c->remote_id);
239 c->remote_id = 0;
240 c->have_remote_id = 0;
241 sc->ctl_chan = -1;
242 if (sc->type != SSH_CHANNEL_OPEN &&
243 sc->type != SSH_CHANNEL_OPENING) {
244 debug2("%s: channel %d: not open", __func__, sc->self);
245 chan_mark_dead(ssh, sc);
246 } else {
247 if (sc->istate == CHAN_INPUT_OPEN)
248 chan_read_failed(ssh, sc);
249 if (sc->ostate == CHAN_OUTPUT_OPEN)
250 chan_write_failed(ssh, sc);
251 }
252 }
253 channel_cancel_cleanup(ssh, c->self);
254 }
255
256 /* Check mux client environment variables before passing them to mux master. */
257 static int
258 env_permitted(char *env)
259 {
260 int i, ret;
261 char name[1024], *cp;
262
263 if ((cp = strchr(env, '=')) == NULL || cp == env)
264 return 0;
265 ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
266 if (ret <= 0 || (size_t)ret >= sizeof(name)) {
267 error("env_permitted: name '%.100s...' too long", env);
268 return 0;
269 }
270
271 for (i = 0; i < options.num_send_env; i++)
272 if (match_pattern(name, options.send_env[i]))
273 return 1;
274
275 return 0;
276 }
277
278 /* Mux master protocol message handlers */
279
280 static int
281 process_mux_master_hello(struct ssh *ssh, u_int rid,
282 Channel *c, Buffer *m, Buffer *r)
283 {
284 u_int ver;
285 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
286
287 if (state == NULL)
288 fatal("%s: channel %d: c->mux_ctx == NULL", __func__, c->self);
289 if (state->hello_rcvd) {
290 error("%s: HELLO received twice", __func__);
291 return -1;
292 }
293 if (buffer_get_int_ret(&ver, m) != 0) {
294 malf:
295 error("%s: malformed message", __func__);
296 return -1;
297 }
298 if (ver != SSHMUX_VER) {
299 error("Unsupported multiplexing protocol version %d "
300 "(expected %d)", ver, SSHMUX_VER);
301 return -1;
302 }
303 debug2("%s: channel %d slave version %u", __func__, c->self, ver);
304
305 /* No extensions are presently defined */
306 while (buffer_len(m) > 0) {
307 char *name = buffer_get_string_ret(m, NULL);
308 char *value = buffer_get_string_ret(m, NULL);
309
310 if (name == NULL || value == NULL) {
311 free(name);
312 free(value);
313 goto malf;
314 }
315 debug2("Unrecognised slave extension \"%s\"", name);
316 free(name);
317 free(value);
318 }
319 state->hello_rcvd = 1;
320 return 0;
321 }
322
323 static int
324 process_mux_new_session(struct ssh *ssh, u_int rid,
325 Channel *c, Buffer *m, Buffer *r)
326 {
327 Channel *nc;
328 struct mux_session_confirm_ctx *cctx;
329 char *reserved, *cmd, *cp;
330 u_int i, j, len, env_len, escape_char, window, packetmax;
331 int new_fd[3];
332
333 /* Reply for SSHMUX_COMMAND_OPEN */
334 cctx = xcalloc(1, sizeof(*cctx));
335 cctx->term = NULL;
336 cctx->rid = rid;
337 cmd = reserved = NULL;
338 cctx->env = NULL;
339 env_len = 0;
340 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
341 buffer_get_int_ret(&cctx->want_tty, m) != 0 ||
342 buffer_get_int_ret(&cctx->want_x_fwd, m) != 0 ||
343 buffer_get_int_ret(&cctx->want_agent_fwd, m) != 0 ||
344 buffer_get_int_ret(&cctx->want_subsys, m) != 0 ||
345 buffer_get_int_ret(&escape_char, m) != 0 ||
346 (cctx->term = buffer_get_string_ret(m, &len)) == NULL ||
347 (cmd = buffer_get_string_ret(m, &len)) == NULL) {
348 malf:
349 free(cmd);
350 free(reserved);
351 for (j = 0; j < env_len; j++)
352 free(cctx->env[j]);
353 free(cctx->env);
354 free(cctx->term);
355 free(cctx);
356 error("%s: malformed message", __func__);
357 return -1;
358 }
359 free(reserved);
360 reserved = NULL;
361
362 while (buffer_len(m) > 0) {
363 #define MUX_MAX_ENV_VARS 4096
364 if ((cp = buffer_get_string_ret(m, &len)) == NULL)
365 goto malf;
366 if (!env_permitted(cp)) {
367 free(cp);
368 continue;
369 }
370 cctx->env = xreallocarray(cctx->env, env_len + 2,
371 sizeof(*cctx->env));
372 cctx->env[env_len++] = cp;
373 cctx->env[env_len] = NULL;
374 if (env_len > MUX_MAX_ENV_VARS) {
375 error(">%d environment variables received, ignoring "
376 "additional", MUX_MAX_ENV_VARS);
377 break;
378 }
379 }
380
381 debug2("%s: channel %d: request tty %d, X %d, agent %d, subsys %d, "
382 "term \"%s\", cmd \"%s\", env %u", __func__, c->self,
383 cctx->want_tty, cctx->want_x_fwd, cctx->want_agent_fwd,
384 cctx->want_subsys, cctx->term, cmd, env_len);
385
386 buffer_init(&cctx->cmd);
387 buffer_append(&cctx->cmd, cmd, strlen(cmd));
388 free(cmd);
389 cmd = NULL;
390
391 /* Gather fds from client */
392 for(i = 0; i < 3; i++) {
393 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
394 error("%s: failed to receive fd %d from slave",
395 __func__, i);
396 for (j = 0; j < i; j++)
397 close(new_fd[j]);
398 for (j = 0; j < env_len; j++)
399 free(cctx->env[j]);
400 free(cctx->env);
401 free(cctx->term);
402 buffer_free(&cctx->cmd);
403 free(cctx);
404
405 /* prepare reply */
406 buffer_put_int(r, MUX_S_FAILURE);
407 buffer_put_int(r, rid);
408 buffer_put_cstring(r,
409 "did not receive file descriptors");
410 return -1;
411 }
412 }
413
414 debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
415 new_fd[0], new_fd[1], new_fd[2]);
416
417 /* XXX support multiple child sessions in future */
418 if (c->have_remote_id) {
419 debug2("%s: session already open", __func__);
420 /* prepare reply */
421 buffer_put_int(r, MUX_S_FAILURE);
422 buffer_put_int(r, rid);
423 buffer_put_cstring(r, "Multiple sessions not supported");
424 cleanup:
425 close(new_fd[0]);
426 close(new_fd[1]);
427 close(new_fd[2]);
428 free(cctx->term);
429 if (env_len != 0) {
430 for (i = 0; i < env_len; i++)
431 free(cctx->env[i]);
432 free(cctx->env);
433 }
434 buffer_free(&cctx->cmd);
435 free(cctx);
436 return 0;
437 }
438
439 if (options.control_master == SSHCTL_MASTER_ASK ||
440 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
441 if (!ask_permission("Allow shared connection to %s? ", host)) {
442 debug2("%s: session refused by user", __func__);
443 /* prepare reply */
444 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
445 buffer_put_int(r, rid);
446 buffer_put_cstring(r, "Permission denied");
447 goto cleanup;
448 }
449 }
450
451 /* Try to pick up ttymodes from client before it goes raw */
452 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
453 error("%s: tcgetattr: %s", __func__, strerror(errno));
454
455 /* enable nonblocking unless tty */
456 if (!isatty(new_fd[0]))
457 set_nonblock(new_fd[0]);
458 if (!isatty(new_fd[1]))
459 set_nonblock(new_fd[1]);
460 if (!isatty(new_fd[2]))
461 set_nonblock(new_fd[2]);
462
463 window = CHAN_SES_WINDOW_DEFAULT;
464 packetmax = CHAN_SES_PACKET_DEFAULT;
465 if (cctx->want_tty) {
466 window >>= 1;
467 packetmax >>= 1;
468 }
469
470 nc = channel_new(ssh, "session", SSH_CHANNEL_OPENING,
471 new_fd[0], new_fd[1], new_fd[2], window, packetmax,
472 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
473
474 nc->ctl_chan = c->self; /* link session -> control channel */
475 c->remote_id = nc->self; /* link control -> session channel */
476 c->have_remote_id = 1;
477
478 if (cctx->want_tty && escape_char != 0xffffffff) {
479 channel_register_filter(ssh, nc->self,
480 client_simple_escape_filter, NULL,
481 client_filter_cleanup,
482 client_new_escape_filter_ctx((int)escape_char));
483 }
484
485 debug2("%s: channel_new: %d linked to control channel %d",
486 __func__, nc->self, nc->ctl_chan);
487
488 channel_send_open(ssh, nc->self);
489 channel_register_open_confirm(ssh, nc->self, mux_session_confirm, cctx);
490 c->mux_pause = 1; /* stop handling messages until open_confirm done */
491 channel_register_cleanup(ssh, nc->self,
492 mux_master_session_cleanup_cb, 1);
493
494 /* reply is deferred, sent by mux_session_confirm */
495 return 0;
496 }
497
498 static int
499 process_mux_alive_check(struct ssh *ssh, u_int rid,
500 Channel *c, Buffer *m, Buffer *r)
501 {
502 debug2("%s: channel %d: alive check", __func__, c->self);
503
504 /* prepare reply */
505 buffer_put_int(r, MUX_S_ALIVE);
506 buffer_put_int(r, rid);
507 buffer_put_int(r, (u_int)getpid());
508
509 return 0;
510 }
511
512 static int
513 process_mux_terminate(struct ssh *ssh, u_int rid,
514 Channel *c, Buffer *m, Buffer *r)
515 {
516 debug2("%s: channel %d: terminate request", __func__, c->self);
517
518 if (options.control_master == SSHCTL_MASTER_ASK ||
519 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
520 if (!ask_permission("Terminate shared connection to %s? ",
521 host)) {
522 debug2("%s: termination refused by user", __func__);
523 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
524 buffer_put_int(r, rid);
525 buffer_put_cstring(r, "Permission denied");
526 return 0;
527 }
528 }
529
530 quit_pending = 1;
531 buffer_put_int(r, MUX_S_OK);
532 buffer_put_int(r, rid);
533 /* XXX exit happens too soon - message never makes it to client */
534 return 0;
535 }
536
537 static char *
538 format_forward(u_int ftype, struct Forward *fwd)
539 {
540 char *ret;
541
542 switch (ftype) {
543 case MUX_FWD_LOCAL:
544 xasprintf(&ret, "local forward %.200s:%d -> %.200s:%d",
545 (fwd->listen_path != NULL) ? fwd->listen_path :
546 (fwd->listen_host == NULL) ?
547 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
548 fwd->listen_host, fwd->listen_port,
549 (fwd->connect_path != NULL) ? fwd->connect_path :
550 fwd->connect_host, fwd->connect_port);
551 break;
552 case MUX_FWD_DYNAMIC:
553 xasprintf(&ret, "dynamic forward %.200s:%d -> *",
554 (fwd->listen_host == NULL) ?
555 (options.fwd_opts.gateway_ports ? "*" : "LOCALHOST") :
556 fwd->listen_host, fwd->listen_port);
557 break;
558 case MUX_FWD_REMOTE:
559 xasprintf(&ret, "remote forward %.200s:%d -> %.200s:%d",
560 (fwd->listen_path != NULL) ? fwd->listen_path :
561 (fwd->listen_host == NULL) ?
562 "LOCALHOST" : fwd->listen_host,
563 fwd->listen_port,
564 (fwd->connect_path != NULL) ? fwd->connect_path :
565 fwd->connect_host, fwd->connect_port);
566 break;
567 default:
568 fatal("%s: unknown forward type %u", __func__, ftype);
569 }
570 return ret;
571 }
572
573 static int
574 compare_host(const char *a, const char *b)
575 {
576 if (a == NULL && b == NULL)
577 return 1;
578 if (a == NULL || b == NULL)
579 return 0;
580 return strcmp(a, b) == 0;
581 }
582
583 static int
584 compare_forward(struct Forward *a, struct Forward *b)
585 {
586 if (!compare_host(a->listen_host, b->listen_host))
587 return 0;
588 if (!compare_host(a->listen_path, b->listen_path))
589 return 0;
590 if (a->listen_port != b->listen_port)
591 return 0;
592 if (!compare_host(a->connect_host, b->connect_host))
593 return 0;
594 if (!compare_host(a->connect_path, b->connect_path))
595 return 0;
596 if (a->connect_port != b->connect_port)
597 return 0;
598
599 return 1;
600 }
601
602 static void
603 mux_confirm_remote_forward(struct ssh *ssh, int type, u_int32_t seq, void *ctxt)
604 {
605 struct mux_channel_confirm_ctx *fctx = ctxt;
606 char *failmsg = NULL;
607 struct Forward *rfwd;
608 Channel *c;
609 Buffer out;
610
611 if ((c = channel_by_id(ssh, fctx->cid)) == NULL) {
612 /* no channel for reply */
613 error("%s: unknown channel", __func__);
614 return;
615 }
616 buffer_init(&out);
617 if (fctx->fid >= options.num_remote_forwards ||
618 (options.remote_forwards[fctx->fid].connect_path == NULL &&
619 options.remote_forwards[fctx->fid].connect_host == NULL)) {
620 xasprintf(&failmsg, "unknown forwarding id %d", fctx->fid);
621 goto fail;
622 }
623 rfwd = &options.remote_forwards[fctx->fid];
624 debug("%s: %s for: listen %d, connect %s:%d", __func__,
625 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
626 rfwd->listen_port, rfwd->connect_path ? rfwd->connect_path :
627 rfwd->connect_host, rfwd->connect_port);
628 if (type == SSH2_MSG_REQUEST_SUCCESS) {
629 if (rfwd->listen_port == 0) {
630 rfwd->allocated_port = packet_get_int();
631 debug("Allocated port %u for mux remote forward"
632 " to %s:%d", rfwd->allocated_port,
633 rfwd->connect_host, rfwd->connect_port);
634 buffer_put_int(&out, MUX_S_REMOTE_PORT);
635 buffer_put_int(&out, fctx->rid);
636 buffer_put_int(&out, rfwd->allocated_port);
637 channel_update_permitted_opens(ssh, rfwd->handle,
638 rfwd->allocated_port);
639 } else {
640 buffer_put_int(&out, MUX_S_OK);
641 buffer_put_int(&out, fctx->rid);
642 }
643 goto out;
644 } else {
645 if (rfwd->listen_port == 0)
646 channel_update_permitted_opens(ssh, rfwd->handle, -1);
647 if (rfwd->listen_path != NULL)
648 xasprintf(&failmsg, "remote port forwarding failed for "
649 "listen path %s", rfwd->listen_path);
650 else
651 xasprintf(&failmsg, "remote port forwarding failed for "
652 "listen port %d", rfwd->listen_port);
653
654 debug2("%s: clearing registered forwarding for listen %d, "
655 "connect %s:%d", __func__, rfwd->listen_port,
656 rfwd->connect_path ? rfwd->connect_path :
657 rfwd->connect_host, rfwd->connect_port);
658
659 free(rfwd->listen_host);
660 free(rfwd->listen_path);
661 free(rfwd->connect_host);
662 free(rfwd->connect_path);
663 memset(rfwd, 0, sizeof(*rfwd));
664 }
665 fail:
666 error("%s: %s", __func__, failmsg);
667 buffer_put_int(&out, MUX_S_FAILURE);
668 buffer_put_int(&out, fctx->rid);
669 buffer_put_cstring(&out, failmsg);
670 free(failmsg);
671 out:
672 buffer_put_string(c->output, buffer_ptr(&out), buffer_len(&out));
673 buffer_free(&out);
674 if (c->mux_pause <= 0)
675 fatal("%s: mux_pause %d", __func__, c->mux_pause);
676 c->mux_pause = 0; /* start processing messages again */
677 }
678
679 static int
680 process_mux_open_fwd(struct ssh *ssh, u_int rid,
681 Channel *c, Buffer *m, Buffer *r)
682 {
683 struct Forward fwd;
684 char *fwd_desc = NULL;
685 char *listen_addr, *connect_addr;
686 u_int ftype;
687 u_int lport, cport;
688 int i, ret = 0, freefwd = 1;
689
690 memset(&fwd, 0, sizeof(fwd));
691
692 /* XXX - lport/cport check redundant */
693 if (buffer_get_int_ret(&ftype, m) != 0 ||
694 (listen_addr = buffer_get_string_ret(m, NULL)) == NULL ||
695 buffer_get_int_ret(&lport, m) != 0 ||
696 (connect_addr = buffer_get_string_ret(m, NULL)) == NULL ||
697 buffer_get_int_ret(&cport, m) != 0 ||
698 (lport != (u_int)PORT_STREAMLOCAL && lport > 65535) ||
699 (cport != (u_int)PORT_STREAMLOCAL && cport > 65535)) {
700 error("%s: malformed message", __func__);
701 ret = -1;
702 goto out;
703 }
704 if (*listen_addr == '\0') {
705 free(listen_addr);
706 listen_addr = NULL;
707 }
708 if (*connect_addr == '\0') {
709 free(connect_addr);
710 connect_addr = NULL;
711 }
712
713 memset(&fwd, 0, sizeof(fwd));
714 fwd.listen_port = lport;
715 if (fwd.listen_port == PORT_STREAMLOCAL)
716 fwd.listen_path = listen_addr;
717 else
718 fwd.listen_host = listen_addr;
719 fwd.connect_port = cport;
720 if (fwd.connect_port == PORT_STREAMLOCAL)
721 fwd.connect_path = connect_addr;
722 else
723 fwd.connect_host = connect_addr;
724
725 debug2("%s: channel %d: request %s", __func__, c->self,
726 (fwd_desc = format_forward(ftype, &fwd)));
727
728 if (ftype != MUX_FWD_LOCAL && ftype != MUX_FWD_REMOTE &&
729 ftype != MUX_FWD_DYNAMIC) {
730 logit("%s: invalid forwarding type %u", __func__, ftype);
731 invalid:
732 free(listen_addr);
733 free(connect_addr);
734 buffer_put_int(r, MUX_S_FAILURE);
735 buffer_put_int(r, rid);
736 buffer_put_cstring(r, "Invalid forwarding request");
737 return 0;
738 }
739 if (ftype == MUX_FWD_DYNAMIC && fwd.listen_path) {
740 logit("%s: streamlocal and dynamic forwards "
741 "are mutually exclusive", __func__);
742 goto invalid;
743 }
744 if (fwd.listen_port != PORT_STREAMLOCAL && fwd.listen_port >= 65536) {
745 logit("%s: invalid listen port %u", __func__,
746 fwd.listen_port);
747 goto invalid;
748 }
749 if ((fwd.connect_port != PORT_STREAMLOCAL &&
750 fwd.connect_port >= 65536) ||
751 (ftype != MUX_FWD_DYNAMIC && ftype != MUX_FWD_REMOTE &&
752 fwd.connect_port == 0)) {
753 logit("%s: invalid connect port %u", __func__,
754 fwd.connect_port);
755 goto invalid;
756 }
757 if (ftype != MUX_FWD_DYNAMIC && fwd.connect_host == NULL &&
758 fwd.connect_path == NULL) {
759 logit("%s: missing connect host", __func__);
760 goto invalid;
761 }
762
763 /* Skip forwards that have already been requested */
764 switch (ftype) {
765 case MUX_FWD_LOCAL:
766 case MUX_FWD_DYNAMIC:
767 for (i = 0; i < options.num_local_forwards; i++) {
768 if (compare_forward(&fwd,
769 options.local_forwards + i)) {
770 exists:
771 debug2("%s: found existing forwarding",
772 __func__);
773 buffer_put_int(r, MUX_S_OK);
774 buffer_put_int(r, rid);
775 goto out;
776 }
777 }
778 break;
779 case MUX_FWD_REMOTE:
780 for (i = 0; i < options.num_remote_forwards; i++) {
781 if (compare_forward(&fwd,
782 options.remote_forwards + i)) {
783 if (fwd.listen_port != 0)
784 goto exists;
785 debug2("%s: found allocated port",
786 __func__);
787 buffer_put_int(r, MUX_S_REMOTE_PORT);
788 buffer_put_int(r, rid);
789 buffer_put_int(r,
790 options.remote_forwards[i].allocated_port);
791 goto out;
792 }
793 }
794 break;
795 }
796
797 if (options.control_master == SSHCTL_MASTER_ASK ||
798 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
799 if (!ask_permission("Open %s on %s?", fwd_desc, host)) {
800 debug2("%s: forwarding refused by user", __func__);
801 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
802 buffer_put_int(r, rid);
803 buffer_put_cstring(r, "Permission denied");
804 goto out;
805 }
806 }
807
808 if (ftype == MUX_FWD_LOCAL || ftype == MUX_FWD_DYNAMIC) {
809 if (!channel_setup_local_fwd_listener(ssh, &fwd,
810 &options.fwd_opts)) {
811 fail:
812 logit("slave-requested %s failed", fwd_desc);
813 buffer_put_int(r, MUX_S_FAILURE);
814 buffer_put_int(r, rid);
815 buffer_put_cstring(r, "Port forwarding failed");
816 goto out;
817 }
818 add_local_forward(&options, &fwd);
819 freefwd = 0;
820 } else {
821 struct mux_channel_confirm_ctx *fctx;
822
823 fwd.handle = channel_request_remote_forwarding(ssh, &fwd);
824 if (fwd.handle < 0)
825 goto fail;
826 add_remote_forward(&options, &fwd);
827 fctx = xcalloc(1, sizeof(*fctx));
828 fctx->cid = c->self;
829 fctx->rid = rid;
830 fctx->fid = options.num_remote_forwards - 1;
831 client_register_global_confirm(mux_confirm_remote_forward,
832 fctx);
833 freefwd = 0;
834 c->mux_pause = 1; /* wait for mux_confirm_remote_forward */
835 /* delayed reply in mux_confirm_remote_forward */
836 goto out;
837 }
838 buffer_put_int(r, MUX_S_OK);
839 buffer_put_int(r, rid);
840 out:
841 free(fwd_desc);
842 if (freefwd) {
843 free(fwd.listen_host);
844 free(fwd.listen_path);
845 free(fwd.connect_host);
846 free(fwd.connect_path);
847 }
848 return ret;
849 }
850
851 static int
852 process_mux_close_fwd(struct ssh *ssh, u_int rid,
853 Channel *c, Buffer *m, Buffer *r)
854 {
855 struct Forward fwd, *found_fwd;
856 char *fwd_desc = NULL;
857 const char *error_reason = NULL;
858 char *listen_addr = NULL, *connect_addr = NULL;
859 u_int ftype;
860 int i, ret = 0;
861 u_int lport, cport;
862
863 memset(&fwd, 0, sizeof(fwd));
864
865 if (buffer_get_int_ret(&ftype, m) != 0 ||
866 (listen_addr = buffer_get_string_ret(m, NULL)) == NULL ||
867 buffer_get_int_ret(&lport, m) != 0 ||
868 (connect_addr = buffer_get_string_ret(m, NULL)) == NULL ||
869 buffer_get_int_ret(&cport, m) != 0 ||
870 (lport != (u_int)PORT_STREAMLOCAL && lport > 65535) ||
871 (cport != (u_int)PORT_STREAMLOCAL && cport > 65535)) {
872 error("%s: malformed message", __func__);
873 ret = -1;
874 goto out;
875 }
876
877 if (*listen_addr == '\0') {
878 free(listen_addr);
879 listen_addr = NULL;
880 }
881 if (*connect_addr == '\0') {
882 free(connect_addr);
883 connect_addr = NULL;
884 }
885
886 memset(&fwd, 0, sizeof(fwd));
887 fwd.listen_port = lport;
888 if (fwd.listen_port == PORT_STREAMLOCAL)
889 fwd.listen_path = listen_addr;
890 else
891 fwd.listen_host = listen_addr;
892 fwd.connect_port = cport;
893 if (fwd.connect_port == PORT_STREAMLOCAL)
894 fwd.connect_path = connect_addr;
895 else
896 fwd.connect_host = connect_addr;
897
898 debug2("%s: channel %d: request cancel %s", __func__, c->self,
899 (fwd_desc = format_forward(ftype, &fwd)));
900
901 /* make sure this has been requested */
902 found_fwd = NULL;
903 switch (ftype) {
904 case MUX_FWD_LOCAL:
905 case MUX_FWD_DYNAMIC:
906 for (i = 0; i < options.num_local_forwards; i++) {
907 if (compare_forward(&fwd,
908 options.local_forwards + i)) {
909 found_fwd = options.local_forwards + i;
910 break;
911 }
912 }
913 break;
914 case MUX_FWD_REMOTE:
915 for (i = 0; i < options.num_remote_forwards; i++) {
916 if (compare_forward(&fwd,
917 options.remote_forwards + i)) {
918 found_fwd = options.remote_forwards + i;
919 break;
920 }
921 }
922 break;
923 }
924
925 if (found_fwd == NULL)
926 error_reason = "port not forwarded";
927 else if (ftype == MUX_FWD_REMOTE) {
928 /*
929 * This shouldn't fail unless we confused the host/port
930 * between options.remote_forwards and permitted_opens.
931 * However, for dynamic allocated listen ports we need
932 * to use the actual listen port.
933 */
934 if (channel_request_rforward_cancel(ssh, found_fwd) == -1)
935 error_reason = "port not in permitted opens";
936 } else { /* local and dynamic forwards */
937 /* Ditto */
938 if (channel_cancel_lport_listener(ssh, &fwd, fwd.connect_port,
939 &options.fwd_opts) == -1)
940 error_reason = "port not found";
941 }
942
943 if (error_reason == NULL) {
944 buffer_put_int(r, MUX_S_OK);
945 buffer_put_int(r, rid);
946
947 free(found_fwd->listen_host);
948 free(found_fwd->listen_path);
949 free(found_fwd->connect_host);
950 free(found_fwd->connect_path);
951 found_fwd->listen_host = found_fwd->connect_host = NULL;
952 found_fwd->listen_path = found_fwd->connect_path = NULL;
953 found_fwd->listen_port = found_fwd->connect_port = 0;
954 } else {
955 buffer_put_int(r, MUX_S_FAILURE);
956 buffer_put_int(r, rid);
957 buffer_put_cstring(r, error_reason);
958 }
959 out:
960 free(fwd_desc);
961 free(listen_addr);
962 free(connect_addr);
963
964 return ret;
965 }
966
967 static int
968 process_mux_stdio_fwd(struct ssh *ssh, u_int rid,
969 Channel *c, Buffer *m, Buffer *r)
970 {
971 Channel *nc;
972 char *reserved, *chost;
973 u_int cport, i, j;
974 int new_fd[2];
975 struct mux_stdio_confirm_ctx *cctx;
976
977 chost = reserved = NULL;
978 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
979 (chost = buffer_get_string_ret(m, NULL)) == NULL ||
980 buffer_get_int_ret(&cport, m) != 0) {
981 free(reserved);
982 free(chost);
983 error("%s: malformed message", __func__);
984 return -1;
985 }
986 free(reserved);
987
988 debug2("%s: channel %d: request stdio fwd to %s:%u",
989 __func__, c->self, chost, cport);
990
991 /* Gather fds from client */
992 for(i = 0; i < 2; i++) {
993 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
994 error("%s: failed to receive fd %d from slave",
995 __func__, i);
996 for (j = 0; j < i; j++)
997 close(new_fd[j]);
998 free(chost);
999
1000 /* prepare reply */
1001 buffer_put_int(r, MUX_S_FAILURE);
1002 buffer_put_int(r, rid);
1003 buffer_put_cstring(r,
1004 "did not receive file descriptors");
1005 return -1;
1006 }
1007 }
1008
1009 debug3("%s: got fds stdin %d, stdout %d", __func__,
1010 new_fd[0], new_fd[1]);
1011
1012 /* XXX support multiple child sessions in future */
1013 if (c->have_remote_id) {
1014 debug2("%s: session already open", __func__);
1015 /* prepare reply */
1016 buffer_put_int(r, MUX_S_FAILURE);
1017 buffer_put_int(r, rid);
1018 buffer_put_cstring(r, "Multiple sessions not supported");
1019 cleanup:
1020 close(new_fd[0]);
1021 close(new_fd[1]);
1022 free(chost);
1023 return 0;
1024 }
1025
1026 if (options.control_master == SSHCTL_MASTER_ASK ||
1027 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
1028 if (!ask_permission("Allow forward to %s:%u? ",
1029 chost, cport)) {
1030 debug2("%s: stdio fwd refused by user", __func__);
1031 /* prepare reply */
1032 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
1033 buffer_put_int(r, rid);
1034 buffer_put_cstring(r, "Permission denied");
1035 goto cleanup;
1036 }
1037 }
1038
1039 /* enable nonblocking unless tty */
1040 if (!isatty(new_fd[0]))
1041 set_nonblock(new_fd[0]);
1042 if (!isatty(new_fd[1]))
1043 set_nonblock(new_fd[1]);
1044
1045 nc = channel_connect_stdio_fwd(ssh, chost, cport, new_fd[0], new_fd[1]);
1046
1047 nc->ctl_chan = c->self; /* link session -> control channel */
1048 c->remote_id = nc->self; /* link control -> session channel */
1049 c->have_remote_id = 1;
1050
1051 debug2("%s: channel_new: %d linked to control channel %d",
1052 __func__, nc->self, nc->ctl_chan);
1053
1054 channel_register_cleanup(ssh, nc->self,
1055 mux_master_session_cleanup_cb, 1);
1056
1057 cctx = xcalloc(1, sizeof(*cctx));
1058 cctx->rid = rid;
1059 channel_register_open_confirm(ssh, nc->self, mux_stdio_confirm, cctx);
1060 c->mux_pause = 1; /* stop handling messages until open_confirm done */
1061
1062 /* reply is deferred, sent by mux_session_confirm */
1063 return 0;
1064 }
1065
1066 /* Callback on open confirmation in mux master for a mux stdio fwd session. */
1067 static void
1068 mux_stdio_confirm(struct ssh *ssh, int id, int success, void *arg)
1069 {
1070 struct mux_stdio_confirm_ctx *cctx = arg;
1071 Channel *c, *cc;
1072 Buffer reply;
1073
1074 if (cctx == NULL)
1075 fatal("%s: cctx == NULL", __func__);
1076 if ((c = channel_by_id(ssh, id)) == NULL)
1077 fatal("%s: no channel for id %d", __func__, id);
1078 if ((cc = channel_by_id(ssh, c->ctl_chan)) == NULL)
1079 fatal("%s: channel %d lacks control channel %d", __func__,
1080 id, c->ctl_chan);
1081
1082 if (!success) {
1083 debug3("%s: sending failure reply", __func__);
1084 /* prepare reply */
1085 buffer_init(&reply);
1086 buffer_put_int(&reply, MUX_S_FAILURE);
1087 buffer_put_int(&reply, cctx->rid);
1088 buffer_put_cstring(&reply, "Session open refused by peer");
1089 goto done;
1090 }
1091
1092 debug3("%s: sending success reply", __func__);
1093 /* prepare reply */
1094 buffer_init(&reply);
1095 buffer_put_int(&reply, MUX_S_SESSION_OPENED);
1096 buffer_put_int(&reply, cctx->rid);
1097 buffer_put_int(&reply, c->self);
1098
1099 done:
1100 /* Send reply */
1101 buffer_put_string(cc->output, buffer_ptr(&reply), buffer_len(&reply));
1102 buffer_free(&reply);
1103
1104 if (cc->mux_pause <= 0)
1105 fatal("%s: mux_pause %d", __func__, cc->mux_pause);
1106 cc->mux_pause = 0; /* start processing messages again */
1107 c->open_confirm_ctx = NULL;
1108 free(cctx);
1109 }
1110
1111 static int
1112 process_mux_stop_listening(struct ssh *ssh, u_int rid,
1113 Channel *c, Buffer *m, Buffer *r)
1114 {
1115 debug("%s: channel %d: stop listening", __func__, c->self);
1116
1117 if (options.control_master == SSHCTL_MASTER_ASK ||
1118 options.control_master == SSHCTL_MASTER_AUTO_ASK) {
1119 if (!ask_permission("Disable further multiplexing on shared "
1120 "connection to %s? ", host)) {
1121 debug2("%s: stop listen refused by user", __func__);
1122 buffer_put_int(r, MUX_S_PERMISSION_DENIED);
1123 buffer_put_int(r, rid);
1124 buffer_put_cstring(r, "Permission denied");
1125 return 0;
1126 }
1127 }
1128
1129 if (mux_listener_channel != NULL) {
1130 channel_free(ssh, mux_listener_channel);
1131 client_stop_mux();
1132 free(options.control_path);
1133 options.control_path = NULL;
1134 mux_listener_channel = NULL;
1135 muxserver_sock = -1;
1136 }
1137
1138 /* prepare reply */
1139 buffer_put_int(r, MUX_S_OK);
1140 buffer_put_int(r, rid);
1141
1142 return 0;
1143 }
1144
1145 static int
1146 process_mux_proxy(struct ssh *ssh, u_int rid,
1147 Channel *c, Buffer *m, Buffer *r)
1148 {
1149 debug("%s: channel %d: proxy request", __func__, c->self);
1150
1151 c->mux_rcb = channel_proxy_downstream;
1152 buffer_put_int(r, MUX_S_PROXY);
1153 buffer_put_int(r, rid);
1154
1155 return 0;
1156 }
1157
1158 /* Channel callbacks fired on read/write from mux slave fd */
1159 static int
1160 mux_master_read_cb(struct ssh *ssh, Channel *c)
1161 {
1162 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
1163 Buffer in, out;
1164 const u_char *ptr;
1165 u_int type, rid, have, i;
1166 int ret = -1;
1167
1168 /* Setup ctx and */
1169 if (c->mux_ctx == NULL) {
1170 state = xcalloc(1, sizeof(*state));
1171 c->mux_ctx = state;
1172 channel_register_cleanup(ssh, c->self,
1173 mux_master_control_cleanup_cb, 0);
1174
1175 /* Send hello */
1176 buffer_init(&out);
1177 buffer_put_int(&out, MUX_MSG_HELLO);
1178 buffer_put_int(&out, SSHMUX_VER);
1179 /* no extensions */
1180 buffer_put_string(c->output, buffer_ptr(&out),
1181 buffer_len(&out));
1182 buffer_free(&out);
1183 debug3("%s: channel %d: hello sent", __func__, c->self);
1184 return 0;
1185 }
1186
1187 buffer_init(&in);
1188 buffer_init(&out);
1189
1190 /* Channel code ensures that we receive whole packets */
1191 if ((ptr = buffer_get_string_ptr_ret(c->input, &have)) == NULL) {
1192 malf:
1193 error("%s: malformed message", __func__);
1194 goto out;
1195 }
1196 buffer_append(&in, ptr, have);
1197
1198 if (buffer_get_int_ret(&type, &in) != 0)
1199 goto malf;
1200 debug3("%s: channel %d packet type 0x%08x len %u",
1201 __func__, c->self, type, buffer_len(&in));
1202
1203 if (type == MUX_MSG_HELLO)
1204 rid = 0;
1205 else {
1206 if (!state->hello_rcvd) {
1207 error("%s: expected MUX_MSG_HELLO(0x%08x), "
1208 "received 0x%08x", __func__, MUX_MSG_HELLO, type);
1209 goto out;
1210 }
1211 if (buffer_get_int_ret(&rid, &in) != 0)
1212 goto malf;
1213 }
1214
1215 for (i = 0; mux_master_handlers[i].handler != NULL; i++) {
1216 if (type == mux_master_handlers[i].type) {
1217 ret = mux_master_handlers[i].handler(ssh, rid,
1218 c, &in, &out);
1219 break;
1220 }
1221 }
1222 if (mux_master_handlers[i].handler == NULL) {
1223 error("%s: unsupported mux message 0x%08x", __func__, type);
1224 buffer_put_int(&out, MUX_S_FAILURE);
1225 buffer_put_int(&out, rid);
1226 buffer_put_cstring(&out, "unsupported request");
1227 ret = 0;
1228 }
1229 /* Enqueue reply packet */
1230 if (buffer_len(&out) != 0) {
1231 buffer_put_string(c->output, buffer_ptr(&out),
1232 buffer_len(&out));
1233 }
1234 out:
1235 buffer_free(&in);
1236 buffer_free(&out);
1237 return ret;
1238 }
1239
1240 void
1241 mux_exit_message(struct ssh *ssh, Channel *c, int exitval)
1242 {
1243 Buffer m;
1244 Channel *mux_chan;
1245
1246 debug3("%s: channel %d: exit message, exitval %d", __func__, c->self,
1247 exitval);
1248
1249 if ((mux_chan = channel_by_id(ssh, c->ctl_chan)) == NULL)
1250 fatal("%s: channel %d missing mux channel %d",
1251 __func__, c->self, c->ctl_chan);
1252
1253 /* Append exit message packet to control socket output queue */
1254 buffer_init(&m);
1255 buffer_put_int(&m, MUX_S_EXIT_MESSAGE);
1256 buffer_put_int(&m, c->self);
1257 buffer_put_int(&m, exitval);
1258
1259 buffer_put_string(mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1260 buffer_free(&m);
1261 }
1262
1263 void
1264 mux_tty_alloc_failed(struct ssh *ssh, Channel *c)
1265 {
1266 Buffer m;
1267 Channel *mux_chan;
1268
1269 debug3("%s: channel %d: TTY alloc failed", __func__, c->self);
1270
1271 if ((mux_chan = channel_by_id(ssh, c->ctl_chan)) == NULL)
1272 fatal("%s: channel %d missing mux channel %d",
1273 __func__, c->self, c->ctl_chan);
1274
1275 /* Append exit message packet to control socket output queue */
1276 buffer_init(&m);
1277 buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL);
1278 buffer_put_int(&m, c->self);
1279
1280 buffer_put_string(mux_chan->output, buffer_ptr(&m), buffer_len(&m));
1281 buffer_free(&m);
1282 }
1283
1284 /* Prepare a mux master to listen on a Unix domain socket. */
1285 void
1286 muxserver_listen(struct ssh *ssh)
1287 {
1288 mode_t old_umask;
1289 char *orig_control_path = options.control_path;
1290 char rbuf[16+1];
1291 u_int i, r;
1292 int oerrno;
1293
1294 if (options.control_path == NULL ||
1295 options.control_master == SSHCTL_MASTER_NO)
1296 return;
1297
1298 debug("setting up multiplex master socket");
1299
1300 /*
1301 * Use a temporary path before listen so we can pseudo-atomically
1302 * establish the listening socket in its final location to avoid
1303 * other processes racing in between bind() and listen() and hitting
1304 * an unready socket.
1305 */
1306 for (i = 0; i < sizeof(rbuf) - 1; i++) {
1307 r = arc4random_uniform(26+26+10);
1308 rbuf[i] = (r < 26) ? 'a' + r :
1309 (r < 26*2) ? 'A' + r - 26 :
1310 '0' + r - 26 - 26;
1311 }
1312 rbuf[sizeof(rbuf) - 1] = '\0';
1313 options.control_path = NULL;
1314 xasprintf(&options.control_path, "%s.%s", orig_control_path, rbuf);
1315 debug3("%s: temporary control path %s", __func__, options.control_path);
1316
1317 old_umask = umask(0177);
1318 muxserver_sock = unix_listener(options.control_path, 64, 0);
1319 oerrno = errno;
1320 umask(old_umask);
1321 if (muxserver_sock < 0) {
1322 if (oerrno == EINVAL || oerrno == EADDRINUSE) {
1323 error("ControlSocket %s already exists, "
1324 "disabling multiplexing", options.control_path);
1325 disable_mux_master:
1326 if (muxserver_sock != -1) {
1327 close(muxserver_sock);
1328 muxserver_sock = -1;
1329 }
1330 free(orig_control_path);
1331 free(options.control_path);
1332 options.control_path = NULL;
1333 options.control_master = SSHCTL_MASTER_NO;
1334 return;
1335 } else {
1336 /* unix_listener() logs the error */
1337 cleanup_exit(255);
1338 }
1339 }
1340
1341 /* Now atomically "move" the mux socket into position */
1342 if (link(options.control_path, orig_control_path) != 0) {
1343 if (errno != EEXIST) {
1344 fatal("%s: link mux listener %s => %s: %s", __func__,
1345 options.control_path, orig_control_path,
1346 strerror(errno));
1347 }
1348 error("ControlSocket %s already exists, disabling multiplexing",
1349 orig_control_path);
1350 unlink(options.control_path);
1351 goto disable_mux_master;
1352 }
1353 unlink(options.control_path);
1354 free(options.control_path);
1355 options.control_path = orig_control_path;
1356
1357 set_nonblock(muxserver_sock);
1358
1359 mux_listener_channel = channel_new(ssh, "mux listener",
1360 SSH_CHANNEL_MUX_LISTENER, muxserver_sock, muxserver_sock, -1,
1361 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1362 0, options.control_path, 1);
1363 mux_listener_channel->mux_rcb = mux_master_read_cb;
1364 debug3("%s: mux listener channel %d fd %d", __func__,
1365 mux_listener_channel->self, mux_listener_channel->sock);
1366 }
1367
1368 /* Callback on open confirmation in mux master for a mux client session. */
1369 static void
1370 mux_session_confirm(struct ssh *ssh, int id, int success, void *arg)
1371 {
1372 struct mux_session_confirm_ctx *cctx = arg;
1373 const char *display;
1374 Channel *c, *cc;
1375 int i;
1376 Buffer reply;
1377
1378 if (cctx == NULL)
1379 fatal("%s: cctx == NULL", __func__);
1380 if ((c = channel_by_id(ssh, id)) == NULL)
1381 fatal("%s: no channel for id %d", __func__, id);
1382 if ((cc = channel_by_id(ssh, c->ctl_chan)) == NULL)
1383 fatal("%s: channel %d lacks control channel %d", __func__,
1384 id, c->ctl_chan);
1385
1386 if (!success) {
1387 debug3("%s: sending failure reply", __func__);
1388 /* prepare reply */
1389 buffer_init(&reply);
1390 buffer_put_int(&reply, MUX_S_FAILURE);
1391 buffer_put_int(&reply, cctx->rid);
1392 buffer_put_cstring(&reply, "Session open refused by peer");
1393 goto done;
1394 }
1395
1396 display = getenv("DISPLAY");
1397 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
1398 char *proto, *data;
1399
1400 /* Get reasonable local authentication information. */
1401 if (client_x11_get_proto(ssh, display, options.xauth_location,
1402 options.forward_x11_trusted, options.forward_x11_timeout,
1403 &proto, &data) == 0) {
1404 /* Request forwarding with authentication spoofing. */
1405 debug("Requesting X11 forwarding with authentication "
1406 "spoofing.");
1407 x11_request_forwarding_with_spoofing(ssh, id,
1408 display, proto, data, 1);
1409 /* XXX exit_on_forward_failure */
1410 client_expect_confirm(ssh, id, "X11 forwarding",
1411 CONFIRM_WARN);
1412 }
1413 }
1414
1415 if (cctx->want_agent_fwd && options.forward_agent) {
1416 debug("Requesting authentication agent forwarding.");
1417 channel_request_start(ssh, id, "auth-agent-req@openssh.com", 0);
1418 packet_send();
1419 }
1420
1421 client_session2_setup(ssh, id, cctx->want_tty, cctx->want_subsys,
1422 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env);
1423
1424 debug3("%s: sending success reply", __func__);
1425 /* prepare reply */
1426 buffer_init(&reply);
1427 buffer_put_int(&reply, MUX_S_SESSION_OPENED);
1428 buffer_put_int(&reply, cctx->rid);
1429 buffer_put_int(&reply, c->self);
1430
1431 done:
1432 /* Send reply */
1433 buffer_put_string(cc->output, buffer_ptr(&reply), buffer_len(&reply));
1434 buffer_free(&reply);
1435
1436 if (cc->mux_pause <= 0)
1437 fatal("%s: mux_pause %d", __func__, cc->mux_pause);
1438 cc->mux_pause = 0; /* start processing messages again */
1439 c->open_confirm_ctx = NULL;
1440 buffer_free(&cctx->cmd);
1441 free(cctx->term);
1442 if (cctx->env != NULL) {
1443 for (i = 0; cctx->env[i] != NULL; i++)
1444 free(cctx->env[i]);
1445 free(cctx->env);
1446 }
1447 free(cctx);
1448 }
1449
1450 /* ** Multiplexing client support */
1451
1452 /* Exit signal handler */
1453 static void
1454 control_client_sighandler(int signo)
1455 {
1456 muxclient_terminate = signo;
1457 }
1458
1459 /*
1460 * Relay signal handler - used to pass some signals from mux client to
1461 * mux master.
1462 */
1463 static void
1464 control_client_sigrelay(int signo)
1465 {
1466 int save_errno = errno;
1467
1468 if (muxserver_pid > 1)
1469 kill(muxserver_pid, signo);
1470
1471 errno = save_errno;
1472 }
1473
1474 static int
1475 mux_client_read(int fd, Buffer *b, u_int need)
1476 {
1477 u_int have;
1478 ssize_t len;
1479 u_char *p;
1480 struct pollfd pfd;
1481
1482 pfd.fd = fd;
1483 pfd.events = POLLIN;
1484 p = buffer_append_space(b, need);
1485 for (have = 0; have < need; ) {
1486 if (muxclient_terminate) {
1487 errno = EINTR;
1488 return -1;
1489 }
1490 len = read(fd, p + have, need - have);
1491 if (len < 0) {
1492 switch (errno) {
1493 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1494 case EWOULDBLOCK:
1495 #endif
1496 case EAGAIN:
1497 (void)poll(&pfd, 1, -1);
1498 /* FALLTHROUGH */
1499 case EINTR:
1500 continue;
1501 default:
1502 return -1;
1503 }
1504 }
1505 if (len == 0) {
1506 errno = EPIPE;
1507 return -1;
1508 }
1509 have += (u_int)len;
1510 }
1511 return 0;
1512 }
1513
1514 static int
1515 mux_client_write_packet(int fd, Buffer *m)
1516 {
1517 Buffer queue;
1518 u_int have, need;
1519 int oerrno, len;
1520 u_char *ptr;
1521 struct pollfd pfd;
1522
1523 pfd.fd = fd;
1524 pfd.events = POLLOUT;
1525 buffer_init(&queue);
1526 buffer_put_string(&queue, buffer_ptr(m), buffer_len(m));
1527
1528 need = buffer_len(&queue);
1529 ptr = buffer_ptr(&queue);
1530
1531 for (have = 0; have < need; ) {
1532 if (muxclient_terminate) {
1533 buffer_free(&queue);
1534 errno = EINTR;
1535 return -1;
1536 }
1537 len = write(fd, ptr + have, need - have);
1538 if (len < 0) {
1539 switch (errno) {
1540 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
1541 case EWOULDBLOCK:
1542 #endif
1543 case EAGAIN:
1544 (void)poll(&pfd, 1, -1);
1545 /* FALLTHROUGH */
1546 case EINTR:
1547 continue;
1548 default:
1549 oerrno = errno;
1550 buffer_free(&queue);
1551 errno = oerrno;
1552 return -1;
1553 }
1554 }
1555 if (len == 0) {
1556 buffer_free(&queue);
1557 errno = EPIPE;
1558 return -1;
1559 }
1560 have += (u_int)len;
1561 }
1562 buffer_free(&queue);
1563 return 0;
1564 }
1565
1566 static int
1567 mux_client_read_packet(int fd, Buffer *m)
1568 {
1569 Buffer queue;
1570 u_int need, have;
1571 const u_char *ptr;
1572 int oerrno;
1573
1574 buffer_init(&queue);
1575 if (mux_client_read(fd, &queue, 4) != 0) {
1576 if ((oerrno = errno) == EPIPE)
1577 debug3("%s: read header failed: %s", __func__,
1578 strerror(errno));
1579 buffer_free(&queue);
1580 errno = oerrno;
1581 return -1;
1582 }
1583 need = get_u32(buffer_ptr(&queue));
1584 if (mux_client_read(fd, &queue, need) != 0) {
1585 oerrno = errno;
1586 debug3("%s: read body failed: %s", __func__, strerror(errno));
1587 buffer_free(&queue);
1588 errno = oerrno;
1589 return -1;
1590 }
1591 ptr = buffer_get_string_ptr(&queue, &have);
1592 buffer_append(m, ptr, have);
1593 buffer_free(&queue);
1594 return 0;
1595 }
1596
1597 static int
1598 mux_client_hello_exchange(int fd)
1599 {
1600 Buffer m;
1601 u_int type, ver;
1602 int ret = -1;
1603
1604 buffer_init(&m);
1605 buffer_put_int(&m, MUX_MSG_HELLO);
1606 buffer_put_int(&m, SSHMUX_VER);
1607 /* no extensions */
1608
1609 if (mux_client_write_packet(fd, &m) != 0) {
1610 debug("%s: write packet: %s", __func__, strerror(errno));
1611 goto out;
1612 }
1613
1614 buffer_clear(&m);
1615
1616 /* Read their HELLO */
1617 if (mux_client_read_packet(fd, &m) != 0) {
1618 debug("%s: read packet failed", __func__);
1619 goto out;
1620 }
1621
1622 type = buffer_get_int(&m);
1623 if (type != MUX_MSG_HELLO) {
1624 error("%s: expected HELLO (%u) received %u",
1625 __func__, MUX_MSG_HELLO, type);
1626 goto out;
1627 }
1628 ver = buffer_get_int(&m);
1629 if (ver != SSHMUX_VER) {
1630 error("Unsupported multiplexing protocol version %d "
1631 "(expected %d)", ver, SSHMUX_VER);
1632 goto out;
1633 }
1634 debug2("%s: master version %u", __func__, ver);
1635 /* No extensions are presently defined */
1636 while (buffer_len(&m) > 0) {
1637 char *name = buffer_get_string(&m, NULL);
1638 char *value = buffer_get_string(&m, NULL);
1639
1640 debug2("Unrecognised master extension \"%s\"", name);
1641 free(name);
1642 free(value);
1643 }
1644 /* success */
1645 ret = 0;
1646 out:
1647 buffer_free(&m);
1648 return ret;
1649 }
1650
1651 static u_int
1652 mux_client_request_alive(int fd)
1653 {
1654 Buffer m;
1655 char *e;
1656 u_int pid, type, rid;
1657
1658 debug3("%s: entering", __func__);
1659
1660 buffer_init(&m);
1661 buffer_put_int(&m, MUX_C_ALIVE_CHECK);
1662 buffer_put_int(&m, muxclient_request_id);
1663
1664 if (mux_client_write_packet(fd, &m) != 0)
1665 fatal("%s: write packet: %s", __func__, strerror(errno));
1666
1667 buffer_clear(&m);
1668
1669 /* Read their reply */
1670 if (mux_client_read_packet(fd, &m) != 0) {
1671 buffer_free(&m);
1672 return 0;
1673 }
1674
1675 type = buffer_get_int(&m);
1676 if (type != MUX_S_ALIVE) {
1677 e = buffer_get_string(&m, NULL);
1678 fatal("%s: master returned error: %s", __func__, e);
1679 }
1680
1681 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1682 fatal("%s: out of sequence reply: my id %u theirs %u",
1683 __func__, muxclient_request_id, rid);
1684 pid = buffer_get_int(&m);
1685 buffer_free(&m);
1686
1687 debug3("%s: done pid = %u", __func__, pid);
1688
1689 muxclient_request_id++;
1690
1691 return pid;
1692 }
1693
1694 static void
1695 mux_client_request_terminate(int fd)
1696 {
1697 Buffer m;
1698 char *e;
1699 u_int type, rid;
1700
1701 debug3("%s: entering", __func__);
1702
1703 buffer_init(&m);
1704 buffer_put_int(&m, MUX_C_TERMINATE);
1705 buffer_put_int(&m, muxclient_request_id);
1706
1707 if (mux_client_write_packet(fd, &m) != 0)
1708 fatal("%s: write packet: %s", __func__, strerror(errno));
1709
1710 buffer_clear(&m);
1711
1712 /* Read their reply */
1713 if (mux_client_read_packet(fd, &m) != 0) {
1714 /* Remote end exited already */
1715 if (errno == EPIPE) {
1716 buffer_free(&m);
1717 return;
1718 }
1719 fatal("%s: read from master failed: %s",
1720 __func__, strerror(errno));
1721 }
1722
1723 type = buffer_get_int(&m);
1724 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1725 fatal("%s: out of sequence reply: my id %u theirs %u",
1726 __func__, muxclient_request_id, rid);
1727 switch (type) {
1728 case MUX_S_OK:
1729 break;
1730 case MUX_S_PERMISSION_DENIED:
1731 e = buffer_get_string(&m, NULL);
1732 fatal("Master refused termination request: %s", e);
1733 case MUX_S_FAILURE:
1734 e = buffer_get_string(&m, NULL);
1735 fatal("%s: termination request failed: %s", __func__, e);
1736 default:
1737 fatal("%s: unexpected response from master 0x%08x",
1738 __func__, type);
1739 }
1740 buffer_free(&m);
1741 muxclient_request_id++;
1742 }
1743
1744 static int
1745 mux_client_forward(int fd, int cancel_flag, u_int ftype, struct Forward *fwd)
1746 {
1747 Buffer m;
1748 char *e, *fwd_desc;
1749 u_int type, rid;
1750
1751 fwd_desc = format_forward(ftype, fwd);
1752 debug("Requesting %s %s",
1753 cancel_flag ? "cancellation of" : "forwarding of", fwd_desc);
1754 free(fwd_desc);
1755
1756 buffer_init(&m);
1757 buffer_put_int(&m, cancel_flag ? MUX_C_CLOSE_FWD : MUX_C_OPEN_FWD);
1758 buffer_put_int(&m, muxclient_request_id);
1759 buffer_put_int(&m, ftype);
1760 if (fwd->listen_path != NULL) {
1761 buffer_put_cstring(&m, fwd->listen_path);
1762 } else {
1763 buffer_put_cstring(&m,
1764 fwd->listen_host == NULL ? "" :
1765 (*fwd->listen_host == '\0' ? "*" : fwd->listen_host));
1766 }
1767 buffer_put_int(&m, fwd->listen_port);
1768 if (fwd->connect_path != NULL) {
1769 buffer_put_cstring(&m, fwd->connect_path);
1770 } else {
1771 buffer_put_cstring(&m,
1772 fwd->connect_host == NULL ? "" : fwd->connect_host);
1773 }
1774 buffer_put_int(&m, fwd->connect_port);
1775
1776 if (mux_client_write_packet(fd, &m) != 0)
1777 fatal("%s: write packet: %s", __func__, strerror(errno));
1778
1779 buffer_clear(&m);
1780
1781 /* Read their reply */
1782 if (mux_client_read_packet(fd, &m) != 0) {
1783 buffer_free(&m);
1784 return -1;
1785 }
1786
1787 type = buffer_get_int(&m);
1788 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1789 fatal("%s: out of sequence reply: my id %u theirs %u",
1790 __func__, muxclient_request_id, rid);
1791 switch (type) {
1792 case MUX_S_OK:
1793 break;
1794 case MUX_S_REMOTE_PORT:
1795 if (cancel_flag)
1796 fatal("%s: got MUX_S_REMOTE_PORT for cancel", __func__);
1797 fwd->allocated_port = buffer_get_int(&m);
1798 verbose("Allocated port %u for remote forward to %s:%d",
1799 fwd->allocated_port,
1800 fwd->connect_host ? fwd->connect_host : "",
1801 fwd->connect_port);
1802 if (muxclient_command == SSHMUX_COMMAND_FORWARD)
1803 fprintf(stdout, "%i\n", fwd->allocated_port);
1804 break;
1805 case MUX_S_PERMISSION_DENIED:
1806 e = buffer_get_string(&m, NULL);
1807 buffer_free(&m);
1808 error("Master refused forwarding request: %s", e);
1809 return -1;
1810 case MUX_S_FAILURE:
1811 e = buffer_get_string(&m, NULL);
1812 buffer_free(&m);
1813 error("%s: forwarding request failed: %s", __func__, e);
1814 return -1;
1815 default:
1816 fatal("%s: unexpected response from master 0x%08x",
1817 __func__, type);
1818 }
1819 buffer_free(&m);
1820
1821 muxclient_request_id++;
1822 return 0;
1823 }
1824
1825 static int
1826 mux_client_forwards(int fd, int cancel_flag)
1827 {
1828 int i, ret = 0;
1829
1830 debug3("%s: %s forwardings: %d local, %d remote", __func__,
1831 cancel_flag ? "cancel" : "request",
1832 options.num_local_forwards, options.num_remote_forwards);
1833
1834 /* XXX ExitOnForwardingFailure */
1835 for (i = 0; i < options.num_local_forwards; i++) {
1836 if (mux_client_forward(fd, cancel_flag,
1837 options.local_forwards[i].connect_port == 0 ?
1838 MUX_FWD_DYNAMIC : MUX_FWD_LOCAL,
1839 options.local_forwards + i) != 0)
1840 ret = -1;
1841 }
1842 for (i = 0; i < options.num_remote_forwards; i++) {
1843 if (mux_client_forward(fd, cancel_flag, MUX_FWD_REMOTE,
1844 options.remote_forwards + i) != 0)
1845 ret = -1;
1846 }
1847 return ret;
1848 }
1849
1850 static int
1851 mux_client_request_session(int fd)
1852 {
1853 Buffer m;
1854 char *e, *term;
1855 u_int i, rid, sid, esid, exitval, type, exitval_seen;
1856 extern char **environ;
1857 int devnull, rawmode;
1858
1859 debug3("%s: entering", __func__);
1860
1861 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
1862 error("%s: master alive request failed", __func__);
1863 return -1;
1864 }
1865
1866 signal(SIGPIPE, SIG_IGN);
1867
1868 if (stdin_null_flag) {
1869 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
1870 fatal("open(/dev/null): %s", strerror(errno));
1871 if (dup2(devnull, STDIN_FILENO) == -1)
1872 fatal("dup2: %s", strerror(errno));
1873 if (devnull > STDERR_FILENO)
1874 close(devnull);
1875 }
1876
1877 term = getenv("TERM");
1878
1879 buffer_init(&m);
1880 buffer_put_int(&m, MUX_C_NEW_SESSION);
1881 buffer_put_int(&m, muxclient_request_id);
1882 buffer_put_cstring(&m, ""); /* reserved */
1883 buffer_put_int(&m, tty_flag);
1884 buffer_put_int(&m, options.forward_x11);
1885 buffer_put_int(&m, options.forward_agent);
1886 buffer_put_int(&m, subsystem_flag);
1887 buffer_put_int(&m, options.escape_char == SSH_ESCAPECHAR_NONE ?
1888 0xffffffff : (u_int)options.escape_char);
1889 buffer_put_cstring(&m, term == NULL ? "" : term);
1890 buffer_put_string(&m, buffer_ptr(&command), buffer_len(&command));
1891
1892 if (options.num_send_env > 0 && environ != NULL) {
1893 /* Pass environment */
1894 for (i = 0; environ[i] != NULL; i++) {
1895 if (env_permitted(environ[i])) {
1896 buffer_put_cstring(&m, environ[i]);
1897 }
1898 }
1899 }
1900
1901 if (mux_client_write_packet(fd, &m) != 0)
1902 fatal("%s: write packet: %s", __func__, strerror(errno));
1903
1904 /* Send the stdio file descriptors */
1905 if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
1906 mm_send_fd(fd, STDOUT_FILENO) == -1 ||
1907 mm_send_fd(fd, STDERR_FILENO) == -1)
1908 fatal("%s: send fds failed", __func__);
1909
1910 debug3("%s: session request sent", __func__);
1911
1912 /* Read their reply */
1913 buffer_clear(&m);
1914 if (mux_client_read_packet(fd, &m) != 0) {
1915 error("%s: read from master failed: %s",
1916 __func__, strerror(errno));
1917 buffer_free(&m);
1918 return -1;
1919 }
1920
1921 type = buffer_get_int(&m);
1922 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
1923 fatal("%s: out of sequence reply: my id %u theirs %u",
1924 __func__, muxclient_request_id, rid);
1925 switch (type) {
1926 case MUX_S_SESSION_OPENED:
1927 sid = buffer_get_int(&m);
1928 debug("%s: master session id: %u", __func__, sid);
1929 break;
1930 case MUX_S_PERMISSION_DENIED:
1931 e = buffer_get_string(&m, NULL);
1932 buffer_free(&m);
1933 error("Master refused session request: %s", e);
1934 return -1;
1935 case MUX_S_FAILURE:
1936 e = buffer_get_string(&m, NULL);
1937 buffer_free(&m);
1938 error("%s: session request failed: %s", __func__, e);
1939 return -1;
1940 default:
1941 buffer_free(&m);
1942 error("%s: unexpected response from master 0x%08x",
1943 __func__, type);
1944 return -1;
1945 }
1946 muxclient_request_id++;
1947
1948 if (pledge("stdio proc tty", NULL) == -1)
1949 fatal("%s pledge(): %s", __func__, strerror(errno));
1950 platform_pledge_mux();
1951
1952 signal(SIGHUP, control_client_sighandler);
1953 signal(SIGINT, control_client_sighandler);
1954 signal(SIGTERM, control_client_sighandler);
1955 signal(SIGWINCH, control_client_sigrelay);
1956
1957 rawmode = tty_flag;
1958 if (tty_flag)
1959 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
1960
1961 /*
1962 * Stick around until the controlee closes the client_fd.
1963 * Before it does, it is expected to write an exit message.
1964 * This process must read the value and wait for the closure of
1965 * the client_fd; if this one closes early, the multiplex master will
1966 * terminate early too (possibly losing data).
1967 */
1968 for (exitval = 255, exitval_seen = 0;;) {
1969 buffer_clear(&m);
1970 if (mux_client_read_packet(fd, &m) != 0)
1971 break;
1972 type = buffer_get_int(&m);
1973 switch (type) {
1974 case MUX_S_TTY_ALLOC_FAIL:
1975 if ((esid = buffer_get_int(&m)) != sid)
1976 fatal("%s: tty alloc fail on unknown session: "
1977 "my id %u theirs %u",
1978 __func__, sid, esid);
1979 leave_raw_mode(options.request_tty ==
1980 REQUEST_TTY_FORCE);
1981 rawmode = 0;
1982 continue;
1983 case MUX_S_EXIT_MESSAGE:
1984 if ((esid = buffer_get_int(&m)) != sid)
1985 fatal("%s: exit on unknown session: "
1986 "my id %u theirs %u",
1987 __func__, sid, esid);
1988 if (exitval_seen)
1989 fatal("%s: exitval sent twice", __func__);
1990 exitval = buffer_get_int(&m);
1991 exitval_seen = 1;
1992 continue;
1993 default:
1994 e = buffer_get_string(&m, NULL);
1995 fatal("%s: master returned error: %s", __func__, e);
1996 }
1997 }
1998
1999 close(fd);
2000 if (rawmode)
2001 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
2002
2003 if (muxclient_terminate) {
2004 debug2("Exiting on signal: %s", strsignal(muxclient_terminate));
2005 exitval = 255;
2006 } else if (!exitval_seen) {
2007 debug2("Control master terminated unexpectedly");
2008 exitval = 255;
2009 } else
2010 debug2("Received exit status from master %d", exitval);
2011
2012 if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
2013 fprintf(stderr, "Shared connection to %s closed.\r\n", host);
2014
2015 exit(exitval);
2016 }
2017
2018 static int
2019 mux_client_proxy(int fd)
2020 {
2021 Buffer m;
2022 char *e;
2023 u_int type, rid;
2024
2025 buffer_init(&m);
2026 buffer_put_int(&m, MUX_C_PROXY);
2027 buffer_put_int(&m, muxclient_request_id);
2028 if (mux_client_write_packet(fd, &m) != 0)
2029 fatal("%s: write packet: %s", __func__, strerror(errno));
2030
2031 buffer_clear(&m);
2032
2033 /* Read their reply */
2034 if (mux_client_read_packet(fd, &m) != 0) {
2035 buffer_free(&m);
2036 return 0;
2037 }
2038 type = buffer_get_int(&m);
2039 if (type != MUX_S_PROXY) {
2040 e = buffer_get_string(&m, NULL);
2041 fatal("%s: master returned error: %s", __func__, e);
2042 }
2043 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
2044 fatal("%s: out of sequence reply: my id %u theirs %u",
2045 __func__, muxclient_request_id, rid);
2046 buffer_free(&m);
2047
2048 debug3("%s: done", __func__);
2049 muxclient_request_id++;
2050 return 0;
2051 }
2052
2053 static int
2054 mux_client_request_stdio_fwd(int fd)
2055 {
2056 Buffer m;
2057 char *e;
2058 u_int type, rid, sid;
2059 int devnull;
2060
2061 debug3("%s: entering", __func__);
2062
2063 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
2064 error("%s: master alive request failed", __func__);
2065 return -1;
2066 }
2067
2068 signal(SIGPIPE, SIG_IGN);
2069
2070 if (stdin_null_flag) {
2071 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
2072 fatal("open(/dev/null): %s", strerror(errno));
2073 if (dup2(devnull, STDIN_FILENO) == -1)
2074 fatal("dup2: %s", strerror(errno));
2075 if (devnull > STDERR_FILENO)
2076 close(devnull);
2077 }
2078
2079 buffer_init(&m);
2080 buffer_put_int(&m, MUX_C_NEW_STDIO_FWD);
2081 buffer_put_int(&m, muxclient_request_id);
2082 buffer_put_cstring(&m, ""); /* reserved */
2083 buffer_put_cstring(&m, options.stdio_forward_host);
2084 buffer_put_int(&m, options.stdio_forward_port);
2085
2086 if (mux_client_write_packet(fd, &m) != 0)
2087 fatal("%s: write packet: %s", __func__, strerror(errno));
2088
2089 /* Send the stdio file descriptors */
2090 if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
2091 mm_send_fd(fd, STDOUT_FILENO) == -1)
2092 fatal("%s: send fds failed", __func__);
2093
2094 if (pledge("stdio proc tty", NULL) == -1)
2095 fatal("%s pledge(): %s", __func__, strerror(errno));
2096 platform_pledge_mux();
2097
2098 debug3("%s: stdio forward request sent", __func__);
2099
2100 /* Read their reply */
2101 buffer_clear(&m);
2102
2103 if (mux_client_read_packet(fd, &m) != 0) {
2104 error("%s: read from master failed: %s",
2105 __func__, strerror(errno));
2106 buffer_free(&m);
2107 return -1;
2108 }
2109
2110 type = buffer_get_int(&m);
2111 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
2112 fatal("%s: out of sequence reply: my id %u theirs %u",
2113 __func__, muxclient_request_id, rid);
2114 switch (type) {
2115 case MUX_S_SESSION_OPENED:
2116 sid = buffer_get_int(&m);
2117 debug("%s: master session id: %u", __func__, sid);
2118 break;
2119 case MUX_S_PERMISSION_DENIED:
2120 e = buffer_get_string(&m, NULL);
2121 buffer_free(&m);
2122 fatal("Master refused stdio forwarding request: %s", e);
2123 case MUX_S_FAILURE:
2124 e = buffer_get_string(&m, NULL);
2125 buffer_free(&m);
2126 fatal("Stdio forwarding request failed: %s", e);
2127 default:
2128 buffer_free(&m);
2129 error("%s: unexpected response from master 0x%08x",
2130 __func__, type);
2131 return -1;
2132 }
2133 muxclient_request_id++;
2134
2135 signal(SIGHUP, control_client_sighandler);
2136 signal(SIGINT, control_client_sighandler);
2137 signal(SIGTERM, control_client_sighandler);
2138 signal(SIGWINCH, control_client_sigrelay);
2139
2140 /*
2141 * Stick around until the controlee closes the client_fd.
2142 */
2143 buffer_clear(&m);
2144 if (mux_client_read_packet(fd, &m) != 0) {
2145 if (errno == EPIPE ||
2146 (errno == EINTR && muxclient_terminate != 0))
2147 return 0;
2148 fatal("%s: mux_client_read_packet: %s",
2149 __func__, strerror(errno));
2150 }
2151 fatal("%s: master returned unexpected message %u", __func__, type);
2152 }
2153
2154 static void
2155 mux_client_request_stop_listening(int fd)
2156 {
2157 Buffer m;
2158 char *e;
2159 u_int type, rid;
2160
2161 debug3("%s: entering", __func__);
2162
2163 buffer_init(&m);
2164 buffer_put_int(&m, MUX_C_STOP_LISTENING);
2165 buffer_put_int(&m, muxclient_request_id);
2166
2167 if (mux_client_write_packet(fd, &m) != 0)
2168 fatal("%s: write packet: %s", __func__, strerror(errno));
2169
2170 buffer_clear(&m);
2171
2172 /* Read their reply */
2173 if (mux_client_read_packet(fd, &m) != 0)
2174 fatal("%s: read from master failed: %s",
2175 __func__, strerror(errno));
2176
2177 type = buffer_get_int(&m);
2178 if ((rid = buffer_get_int(&m)) != muxclient_request_id)
2179 fatal("%s: out of sequence reply: my id %u theirs %u",
2180 __func__, muxclient_request_id, rid);
2181 switch (type) {
2182 case MUX_S_OK:
2183 break;
2184 case MUX_S_PERMISSION_DENIED:
2185 e = buffer_get_string(&m, NULL);
2186 fatal("Master refused stop listening request: %s", e);
2187 case MUX_S_FAILURE:
2188 e = buffer_get_string(&m, NULL);
2189 fatal("%s: stop listening request failed: %s", __func__, e);
2190 default:
2191 fatal("%s: unexpected response from master 0x%08x",
2192 __func__, type);
2193 }
2194 buffer_free(&m);
2195 muxclient_request_id++;
2196 }
2197
2198 /* Multiplex client main loop. */
2199 int
2200 muxclient(const char *path)
2201 {
2202 struct sockaddr_un addr;
2203 int sock;
2204 u_int pid;
2205
2206 if (muxclient_command == 0) {
2207 if (options.stdio_forward_host != NULL)
2208 muxclient_command = SSHMUX_COMMAND_STDIO_FWD;
2209 else
2210 muxclient_command = SSHMUX_COMMAND_OPEN;
2211 }
2212
2213 switch (options.control_master) {
2214 case SSHCTL_MASTER_AUTO:
2215 case SSHCTL_MASTER_AUTO_ASK:
2216 debug("auto-mux: Trying existing master");
2217 /* FALLTHROUGH */
2218 case SSHCTL_MASTER_NO:
2219 break;
2220 default:
2221 return -1;
2222 }
2223
2224 memset(&addr, '\0', sizeof(addr));
2225 addr.sun_family = AF_UNIX;
2226
2227 if (strlcpy(addr.sun_path, path,
2228 sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
2229 fatal("ControlPath too long ('%s' >= %u bytes)", path,
2230 (unsigned int)sizeof(addr.sun_path));
2231
2232 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
2233 fatal("%s socket(): %s", __func__, strerror(errno));
2234
2235 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
2236 switch (muxclient_command) {
2237 case SSHMUX_COMMAND_OPEN:
2238 case SSHMUX_COMMAND_STDIO_FWD:
2239 break;
2240 default:
2241 fatal("Control socket connect(%.100s): %s", path,
2242 strerror(errno));
2243 }
2244 if (errno == ECONNREFUSED &&
2245 options.control_master != SSHCTL_MASTER_NO) {
2246 debug("Stale control socket %.100s, unlinking", path);
2247 unlink(path);
2248 } else if (errno == ENOENT) {
2249 debug("Control socket \"%.100s\" does not exist", path);
2250 } else {
2251 error("Control socket connect(%.100s): %s", path,
2252 strerror(errno));
2253 }
2254 close(sock);
2255 return -1;
2256 }
2257 set_nonblock(sock);
2258
2259 if (mux_client_hello_exchange(sock) != 0) {
2260 error("%s: master hello exchange failed", __func__);
2261 close(sock);
2262 return -1;
2263 }
2264
2265 switch (muxclient_command) {
2266 case SSHMUX_COMMAND_ALIVE_CHECK:
2267 if ((pid = mux_client_request_alive(sock)) == 0)
2268 fatal("%s: master alive check failed", __func__);
2269 fprintf(stderr, "Master running (pid=%u)\r\n", pid);
2270 exit(0);
2271 case SSHMUX_COMMAND_TERMINATE:
2272 mux_client_request_terminate(sock);
2273 if (options.log_level != SYSLOG_LEVEL_QUIET)
2274 fprintf(stderr, "Exit request sent.\r\n");
2275 exit(0);
2276 case SSHMUX_COMMAND_FORWARD:
2277 if (mux_client_forwards(sock, 0) != 0)
2278 fatal("%s: master forward request failed", __func__);
2279 exit(0);
2280 case SSHMUX_COMMAND_OPEN:
2281 if (mux_client_forwards(sock, 0) != 0) {
2282 error("%s: master forward request failed", __func__);
2283 return -1;
2284 }
2285 mux_client_request_session(sock);
2286 return -1;
2287 case SSHMUX_COMMAND_STDIO_FWD:
2288 mux_client_request_stdio_fwd(sock);
2289 exit(0);
2290 case SSHMUX_COMMAND_STOP:
2291 mux_client_request_stop_listening(sock);
2292 if (options.log_level != SYSLOG_LEVEL_QUIET)
2293 fprintf(stderr, "Stop listening request sent.\r\n");
2294 exit(0);
2295 case SSHMUX_COMMAND_CANCEL_FWD:
2296 if (mux_client_forwards(sock, 1) != 0)
2297 error("%s: master cancel forward request failed",
2298 __func__);
2299 exit(0);
2300 case SSHMUX_COMMAND_PROXY:
2301 mux_client_proxy(sock);
2302 return (sock);
2303 default:
2304 fatal("unrecognised muxclient_command %d", muxclient_command);
2305 }
2306 }
DragonFly BSD