mux.c revision 287147
1/* $OpenBSD: mux.c,v 1.44 2013/07/12 00:19:58 djm Exp $ */ 2/* $FreeBSD: releng/9.3/crypto/openssh/mux.c 287147 2015-08-25 20:49:05Z delphij $ */ 3/* 4 * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19/* ssh session multiplexing support */ 20 21/* 22 * TODO: 23 * - Better signalling from master to slave, especially passing of 24 * error messages 25 * - Better fall-back from mux slave error to new connection. 26 * - ExitOnForwardingFailure 27 * - Maybe extension mechanisms for multi-X11/multi-agent forwarding 28 * - Support ~^Z in mux slaves. 29 * - Inspect or control sessions in master. 30 * - If we ever support the "signal" channel request, send signals on 31 * sessions in master. 32 */ 33 34#include "includes.h" 35__RCSID("$FreeBSD: releng/9.3/crypto/openssh/mux.c 287147 2015-08-25 20:49:05Z delphij $"); 36 37#include <sys/types.h> 38#include <sys/param.h> 39#include <sys/stat.h> 40#include <sys/socket.h> 41#include <sys/un.h> 42 43#include <errno.h> 44#include <fcntl.h> 45#include <signal.h> 46#include <stdarg.h> 47#include <stddef.h> 48#include <stdlib.h> 49#include <stdio.h> 50#include <string.h> 51#include <unistd.h> 52#ifdef HAVE_PATHS_H 53#include <paths.h> 54#endif 55 56#ifdef HAVE_POLL_H 57#include <poll.h> 58#else 59# ifdef HAVE_SYS_POLL_H 60# include <sys/poll.h> 61# endif 62#endif 63 64#ifdef HAVE_UTIL_H 65# include <util.h> 66#endif 67 68#include "openbsd-compat/sys-queue.h" 69#include "xmalloc.h" 70#include "log.h" 71#include "ssh.h" 72#include "ssh2.h" 73#include "pathnames.h" 74#include "misc.h" 75#include "match.h" 76#include "buffer.h" 77#include "channels.h" 78#include "msg.h" 79#include "packet.h" 80#include "monitor_fdpass.h" 81#include "sshpty.h" 82#include "key.h" 83#include "readconf.h" 84#include "clientloop.h" 85 86/* from ssh.c */ 87extern int tty_flag; 88extern Options options; 89extern int stdin_null_flag; 90extern char *host; 91extern int subsystem_flag; 92extern Buffer command; 93extern volatile sig_atomic_t quit_pending; 94extern char *stdio_forward_host; 95extern int stdio_forward_port; 96 97/* Context for session open confirmation callback */ 98struct mux_session_confirm_ctx { 99 u_int want_tty; 100 u_int want_subsys; 101 u_int want_x_fwd; 102 u_int want_agent_fwd; 103 Buffer cmd; 104 char *term; 105 struct termios tio; 106 char **env; 107 u_int rid; 108}; 109 110/* Context for global channel callback */ 111struct mux_channel_confirm_ctx { 112 u_int cid; /* channel id */ 113 u_int rid; /* request id */ 114 int fid; /* forward id */ 115}; 116 117/* fd to control socket */ 118int muxserver_sock = -1; 119 120/* client request id */ 121u_int muxclient_request_id = 0; 122 123/* Multiplexing control command */ 124u_int muxclient_command = 0; 125 126/* Set when signalled. */ 127static volatile sig_atomic_t muxclient_terminate = 0; 128 129/* PID of multiplex server */ 130static u_int muxserver_pid = 0; 131 132static Channel *mux_listener_channel = NULL; 133 134struct mux_master_state { 135 int hello_rcvd; 136}; 137 138/* mux protocol messages */ 139#define MUX_MSG_HELLO 0x00000001 140#define MUX_C_NEW_SESSION 0x10000002 141#define MUX_C_ALIVE_CHECK 0x10000004 142#define MUX_C_TERMINATE 0x10000005 143#define MUX_C_OPEN_FWD 0x10000006 144#define MUX_C_CLOSE_FWD 0x10000007 145#define MUX_C_NEW_STDIO_FWD 0x10000008 146#define MUX_C_STOP_LISTENING 0x10000009 147#define MUX_S_OK 0x80000001 148#define MUX_S_PERMISSION_DENIED 0x80000002 149#define MUX_S_FAILURE 0x80000003 150#define MUX_S_EXIT_MESSAGE 0x80000004 151#define MUX_S_ALIVE 0x80000005 152#define MUX_S_SESSION_OPENED 0x80000006 153#define MUX_S_REMOTE_PORT 0x80000007 154#define MUX_S_TTY_ALLOC_FAIL 0x80000008 155 156/* type codes for MUX_C_OPEN_FWD and MUX_C_CLOSE_FWD */ 157#define MUX_FWD_LOCAL 1 158#define MUX_FWD_REMOTE 2 159#define MUX_FWD_DYNAMIC 3 160 161static void mux_session_confirm(int, int, void *); 162 163static int process_mux_master_hello(u_int, Channel *, Buffer *, Buffer *); 164static int process_mux_new_session(u_int, Channel *, Buffer *, Buffer *); 165static int process_mux_alive_check(u_int, Channel *, Buffer *, Buffer *); 166static int process_mux_terminate(u_int, Channel *, Buffer *, Buffer *); 167static int process_mux_open_fwd(u_int, Channel *, Buffer *, Buffer *); 168static int process_mux_close_fwd(u_int, Channel *, Buffer *, Buffer *); 169static int process_mux_stdio_fwd(u_int, Channel *, Buffer *, Buffer *); 170static int process_mux_stop_listening(u_int, Channel *, Buffer *, Buffer *); 171 172static const struct { 173 u_int type; 174 int (*handler)(u_int, Channel *, Buffer *, Buffer *); 175} mux_master_handlers[] = { 176 { MUX_MSG_HELLO, process_mux_master_hello }, 177 { MUX_C_NEW_SESSION, process_mux_new_session }, 178 { MUX_C_ALIVE_CHECK, process_mux_alive_check }, 179 { MUX_C_TERMINATE, process_mux_terminate }, 180 { MUX_C_OPEN_FWD, process_mux_open_fwd }, 181 { MUX_C_CLOSE_FWD, process_mux_close_fwd }, 182 { MUX_C_NEW_STDIO_FWD, process_mux_stdio_fwd }, 183 { MUX_C_STOP_LISTENING, process_mux_stop_listening }, 184 { 0, NULL } 185}; 186 187/* Cleanup callback fired on closure of mux slave _session_ channel */ 188/* ARGSUSED */ 189static void 190mux_master_session_cleanup_cb(int cid, void *unused) 191{ 192 Channel *cc, *c = channel_by_id(cid); 193 194 debug3("%s: entering for channel %d", __func__, cid); 195 if (c == NULL) 196 fatal("%s: channel_by_id(%i) == NULL", __func__, cid); 197 if (c->ctl_chan != -1) { 198 if ((cc = channel_by_id(c->ctl_chan)) == NULL) 199 fatal("%s: channel %d missing control channel %d", 200 __func__, c->self, c->ctl_chan); 201 c->ctl_chan = -1; 202 cc->remote_id = -1; 203 chan_rcvd_oclose(cc); 204 } 205 channel_cancel_cleanup(c->self); 206} 207 208/* Cleanup callback fired on closure of mux slave _control_ channel */ 209/* ARGSUSED */ 210static void 211mux_master_control_cleanup_cb(int cid, void *unused) 212{ 213 Channel *sc, *c = channel_by_id(cid); 214 215 debug3("%s: entering for channel %d", __func__, cid); 216 if (c == NULL) 217 fatal("%s: channel_by_id(%i) == NULL", __func__, cid); 218 if (c->remote_id != -1) { 219 if ((sc = channel_by_id(c->remote_id)) == NULL) 220 fatal("%s: channel %d missing session channel %d", 221 __func__, c->self, c->remote_id); 222 c->remote_id = -1; 223 sc->ctl_chan = -1; 224 if (sc->type != SSH_CHANNEL_OPEN && 225 sc->type != SSH_CHANNEL_OPENING) { 226 debug2("%s: channel %d: not open", __func__, sc->self); 227 chan_mark_dead(sc); 228 } else { 229 if (sc->istate == CHAN_INPUT_OPEN) 230 chan_read_failed(sc); 231 if (sc->ostate == CHAN_OUTPUT_OPEN) 232 chan_write_failed(sc); 233 } 234 } 235 channel_cancel_cleanup(c->self); 236} 237 238/* Check mux client environment variables before passing them to mux master. */ 239static int 240env_permitted(char *env) 241{ 242 int i, ret; 243 char name[1024], *cp; 244 245 if ((cp = strchr(env, '=')) == NULL || cp == env) 246 return 0; 247 ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env); 248 if (ret <= 0 || (size_t)ret >= sizeof(name)) { 249 error("env_permitted: name '%.100s...' too long", env); 250 return 0; 251 } 252 253 for (i = 0; i < options.num_send_env; i++) 254 if (match_pattern(name, options.send_env[i])) 255 return 1; 256 257 return 0; 258} 259 260/* Mux master protocol message handlers */ 261 262static int 263process_mux_master_hello(u_int rid, Channel *c, Buffer *m, Buffer *r) 264{ 265 u_int ver; 266 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx; 267 268 if (state == NULL) 269 fatal("%s: channel %d: c->mux_ctx == NULL", __func__, c->self); 270 if (state->hello_rcvd) { 271 error("%s: HELLO received twice", __func__); 272 return -1; 273 } 274 if (buffer_get_int_ret(&ver, m) != 0) { 275 malf: 276 error("%s: malformed message", __func__); 277 return -1; 278 } 279 if (ver != SSHMUX_VER) { 280 error("Unsupported multiplexing protocol version %d " 281 "(expected %d)", ver, SSHMUX_VER); 282 return -1; 283 } 284 debug2("%s: channel %d slave version %u", __func__, c->self, ver); 285 286 /* No extensions are presently defined */ 287 while (buffer_len(m) > 0) { 288 char *name = buffer_get_string_ret(m, NULL); 289 char *value = buffer_get_string_ret(m, NULL); 290 291 if (name == NULL || value == NULL) { 292 free(name); 293 free(value); 294 goto malf; 295 } 296 debug2("Unrecognised slave extension \"%s\"", name); 297 free(name); 298 free(value); 299 } 300 state->hello_rcvd = 1; 301 return 0; 302} 303 304static int 305process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r) 306{ 307 Channel *nc; 308 struct mux_session_confirm_ctx *cctx; 309 char *reserved, *cmd, *cp; 310 u_int i, j, len, env_len, escape_char, window, packetmax; 311 int new_fd[3]; 312 313 /* Reply for SSHMUX_COMMAND_OPEN */ 314 cctx = xcalloc(1, sizeof(*cctx)); 315 cctx->term = NULL; 316 cctx->rid = rid; 317 cmd = reserved = NULL; 318 cctx->env = NULL; 319 env_len = 0; 320 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL || 321 buffer_get_int_ret(&cctx->want_tty, m) != 0 || 322 buffer_get_int_ret(&cctx->want_x_fwd, m) != 0 || 323 buffer_get_int_ret(&cctx->want_agent_fwd, m) != 0 || 324 buffer_get_int_ret(&cctx->want_subsys, m) != 0 || 325 buffer_get_int_ret(&escape_char, m) != 0 || 326 (cctx->term = buffer_get_string_ret(m, &len)) == NULL || 327 (cmd = buffer_get_string_ret(m, &len)) == NULL) { 328 malf: 329 free(cmd); 330 free(reserved); 331 for (j = 0; j < env_len; j++) 332 free(cctx->env[j]); 333 free(cctx->env); 334 free(cctx->term); 335 free(cctx); 336 error("%s: malformed message", __func__); 337 return -1; 338 } 339 free(reserved); 340 reserved = NULL; 341 342 while (buffer_len(m) > 0) { 343#define MUX_MAX_ENV_VARS 4096 344 if ((cp = buffer_get_string_ret(m, &len)) == NULL) 345 goto malf; 346 if (!env_permitted(cp)) { 347 free(cp); 348 continue; 349 } 350 cctx->env = xrealloc(cctx->env, env_len + 2, 351 sizeof(*cctx->env)); 352 cctx->env[env_len++] = cp; 353 cctx->env[env_len] = NULL; 354 if (env_len > MUX_MAX_ENV_VARS) { 355 error(">%d environment variables received, ignoring " 356 "additional", MUX_MAX_ENV_VARS); 357 break; 358 } 359 } 360 361 debug2("%s: channel %d: request tty %d, X %d, agent %d, subsys %d, " 362 "term \"%s\", cmd \"%s\", env %u", __func__, c->self, 363 cctx->want_tty, cctx->want_x_fwd, cctx->want_agent_fwd, 364 cctx->want_subsys, cctx->term, cmd, env_len); 365 366 buffer_init(&cctx->cmd); 367 buffer_append(&cctx->cmd, cmd, strlen(cmd)); 368 free(cmd); 369 cmd = NULL; 370 371 /* Gather fds from client */ 372 for(i = 0; i < 3; i++) { 373 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) { 374 error("%s: failed to receive fd %d from slave", 375 __func__, i); 376 for (j = 0; j < i; j++) 377 close(new_fd[j]); 378 for (j = 0; j < env_len; j++) 379 free(cctx->env[j]); 380 free(cctx->env); 381 free(cctx->term); 382 buffer_free(&cctx->cmd); 383 free(cctx); 384 385 /* prepare reply */ 386 buffer_put_int(r, MUX_S_FAILURE); 387 buffer_put_int(r, rid); 388 buffer_put_cstring(r, 389 "did not receive file descriptors"); 390 return -1; 391 } 392 } 393 394 debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__, 395 new_fd[0], new_fd[1], new_fd[2]); 396 397 /* XXX support multiple child sessions in future */ 398 if (c->remote_id != -1) { 399 debug2("%s: session already open", __func__); 400 /* prepare reply */ 401 buffer_put_int(r, MUX_S_FAILURE); 402 buffer_put_int(r, rid); 403 buffer_put_cstring(r, "Multiple sessions not supported"); 404 cleanup: 405 close(new_fd[0]); 406 close(new_fd[1]); 407 close(new_fd[2]); 408 free(cctx->term); 409 if (env_len != 0) { 410 for (i = 0; i < env_len; i++) 411 free(cctx->env[i]); 412 free(cctx->env); 413 } 414 buffer_free(&cctx->cmd); 415 free(cctx); 416 return 0; 417 } 418 419 if (options.control_master == SSHCTL_MASTER_ASK || 420 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 421 if (!ask_permission("Allow shared connection to %s? ", host)) { 422 debug2("%s: session refused by user", __func__); 423 /* prepare reply */ 424 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 425 buffer_put_int(r, rid); 426 buffer_put_cstring(r, "Permission denied"); 427 goto cleanup; 428 } 429 } 430 431 /* Try to pick up ttymodes from client before it goes raw */ 432 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1) 433 error("%s: tcgetattr: %s", __func__, strerror(errno)); 434 435 /* enable nonblocking unless tty */ 436 if (!isatty(new_fd[0])) 437 set_nonblock(new_fd[0]); 438 if (!isatty(new_fd[1])) 439 set_nonblock(new_fd[1]); 440 if (!isatty(new_fd[2])) 441 set_nonblock(new_fd[2]); 442 443 window = CHAN_SES_WINDOW_DEFAULT; 444 packetmax = CHAN_SES_PACKET_DEFAULT; 445 if (cctx->want_tty) { 446 window >>= 1; 447 packetmax >>= 1; 448 } 449 450 nc = channel_new("session", SSH_CHANNEL_OPENING, 451 new_fd[0], new_fd[1], new_fd[2], window, packetmax, 452 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); 453 454 nc->ctl_chan = c->self; /* link session -> control channel */ 455 c->remote_id = nc->self; /* link control -> session channel */ 456 457 if (cctx->want_tty && escape_char != 0xffffffff) { 458 channel_register_filter(nc->self, 459 client_simple_escape_filter, NULL, 460 client_filter_cleanup, 461 client_new_escape_filter_ctx((int)escape_char)); 462 } 463 464 debug2("%s: channel_new: %d linked to control channel %d", 465 __func__, nc->self, nc->ctl_chan); 466 467 channel_send_open(nc->self); 468 channel_register_open_confirm(nc->self, mux_session_confirm, cctx); 469 c->mux_pause = 1; /* stop handling messages until open_confirm done */ 470 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1); 471 472 /* reply is deferred, sent by mux_session_confirm */ 473 return 0; 474} 475 476static int 477process_mux_alive_check(u_int rid, Channel *c, Buffer *m, Buffer *r) 478{ 479 debug2("%s: channel %d: alive check", __func__, c->self); 480 481 /* prepare reply */ 482 buffer_put_int(r, MUX_S_ALIVE); 483 buffer_put_int(r, rid); 484 buffer_put_int(r, (u_int)getpid()); 485 486 return 0; 487} 488 489static int 490process_mux_terminate(u_int rid, Channel *c, Buffer *m, Buffer *r) 491{ 492 debug2("%s: channel %d: terminate request", __func__, c->self); 493 494 if (options.control_master == SSHCTL_MASTER_ASK || 495 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 496 if (!ask_permission("Terminate shared connection to %s? ", 497 host)) { 498 debug2("%s: termination refused by user", __func__); 499 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 500 buffer_put_int(r, rid); 501 buffer_put_cstring(r, "Permission denied"); 502 return 0; 503 } 504 } 505 506 quit_pending = 1; 507 buffer_put_int(r, MUX_S_OK); 508 buffer_put_int(r, rid); 509 /* XXX exit happens too soon - message never makes it to client */ 510 return 0; 511} 512 513static char * 514format_forward(u_int ftype, Forward *fwd) 515{ 516 char *ret; 517 518 switch (ftype) { 519 case MUX_FWD_LOCAL: 520 xasprintf(&ret, "local forward %.200s:%d -> %.200s:%d", 521 (fwd->listen_host == NULL) ? 522 (options.gateway_ports ? "*" : "LOCALHOST") : 523 fwd->listen_host, fwd->listen_port, 524 fwd->connect_host, fwd->connect_port); 525 break; 526 case MUX_FWD_DYNAMIC: 527 xasprintf(&ret, "dynamic forward %.200s:%d -> *", 528 (fwd->listen_host == NULL) ? 529 (options.gateway_ports ? "*" : "LOCALHOST") : 530 fwd->listen_host, fwd->listen_port); 531 break; 532 case MUX_FWD_REMOTE: 533 xasprintf(&ret, "remote forward %.200s:%d -> %.200s:%d", 534 (fwd->listen_host == NULL) ? 535 "LOCALHOST" : fwd->listen_host, 536 fwd->listen_port, 537 fwd->connect_host, fwd->connect_port); 538 break; 539 default: 540 fatal("%s: unknown forward type %u", __func__, ftype); 541 } 542 return ret; 543} 544 545static int 546compare_host(const char *a, const char *b) 547{ 548 if (a == NULL && b == NULL) 549 return 1; 550 if (a == NULL || b == NULL) 551 return 0; 552 return strcmp(a, b) == 0; 553} 554 555static int 556compare_forward(Forward *a, Forward *b) 557{ 558 if (!compare_host(a->listen_host, b->listen_host)) 559 return 0; 560 if (a->listen_port != b->listen_port) 561 return 0; 562 if (!compare_host(a->connect_host, b->connect_host)) 563 return 0; 564 if (a->connect_port != b->connect_port) 565 return 0; 566 567 return 1; 568} 569 570static void 571mux_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 572{ 573 struct mux_channel_confirm_ctx *fctx = ctxt; 574 char *failmsg = NULL; 575 Forward *rfwd; 576 Channel *c; 577 Buffer out; 578 579 if ((c = channel_by_id(fctx->cid)) == NULL) { 580 /* no channel for reply */ 581 error("%s: unknown channel", __func__); 582 return; 583 } 584 buffer_init(&out); 585 if (fctx->fid >= options.num_remote_forwards) { 586 xasprintf(&failmsg, "unknown forwarding id %d", fctx->fid); 587 goto fail; 588 } 589 rfwd = &options.remote_forwards[fctx->fid]; 590 debug("%s: %s for: listen %d, connect %s:%d", __func__, 591 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 592 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 593 if (type == SSH2_MSG_REQUEST_SUCCESS) { 594 if (rfwd->listen_port == 0) { 595 rfwd->allocated_port = packet_get_int(); 596 logit("Allocated port %u for mux remote forward" 597 " to %s:%d", rfwd->allocated_port, 598 rfwd->connect_host, rfwd->connect_port); 599 buffer_put_int(&out, MUX_S_REMOTE_PORT); 600 buffer_put_int(&out, fctx->rid); 601 buffer_put_int(&out, rfwd->allocated_port); 602 channel_update_permitted_opens(rfwd->handle, 603 rfwd->allocated_port); 604 } else { 605 buffer_put_int(&out, MUX_S_OK); 606 buffer_put_int(&out, fctx->rid); 607 } 608 goto out; 609 } else { 610 if (rfwd->listen_port == 0) 611 channel_update_permitted_opens(rfwd->handle, -1); 612 xasprintf(&failmsg, "remote port forwarding failed for " 613 "listen port %d", rfwd->listen_port); 614 } 615 fail: 616 error("%s: %s", __func__, failmsg); 617 buffer_put_int(&out, MUX_S_FAILURE); 618 buffer_put_int(&out, fctx->rid); 619 buffer_put_cstring(&out, failmsg); 620 free(failmsg); 621 out: 622 buffer_put_string(&c->output, buffer_ptr(&out), buffer_len(&out)); 623 buffer_free(&out); 624 if (c->mux_pause <= 0) 625 fatal("%s: mux_pause %d", __func__, c->mux_pause); 626 c->mux_pause = 0; /* start processing messages again */ 627} 628 629static int 630process_mux_open_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r) 631{ 632 Forward fwd; 633 char *fwd_desc = NULL; 634 u_int ftype; 635 u_int lport, cport; 636 int i, ret = 0, freefwd = 1; 637 638 memset(&fwd, 0, sizeof(fwd)); 639 640 if (buffer_get_int_ret(&ftype, m) != 0 || 641 (fwd.listen_host = buffer_get_string_ret(m, NULL)) == NULL || 642 buffer_get_int_ret(&lport, m) != 0 || 643 (fwd.connect_host = buffer_get_string_ret(m, NULL)) == NULL || 644 buffer_get_int_ret(&cport, m) != 0 || 645 lport > 65535 || cport > 65535) { 646 error("%s: malformed message", __func__); 647 ret = -1; 648 goto out; 649 } 650 fwd.listen_port = lport; 651 fwd.connect_port = cport; 652 if (*fwd.listen_host == '\0') { 653 free(fwd.listen_host); 654 fwd.listen_host = NULL; 655 } 656 if (*fwd.connect_host == '\0') { 657 free(fwd.connect_host); 658 fwd.connect_host = NULL; 659 } 660 661 debug2("%s: channel %d: request %s", __func__, c->self, 662 (fwd_desc = format_forward(ftype, &fwd))); 663 664 if (ftype != MUX_FWD_LOCAL && ftype != MUX_FWD_REMOTE && 665 ftype != MUX_FWD_DYNAMIC) { 666 logit("%s: invalid forwarding type %u", __func__, ftype); 667 invalid: 668 free(fwd.listen_host); 669 free(fwd.connect_host); 670 buffer_put_int(r, MUX_S_FAILURE); 671 buffer_put_int(r, rid); 672 buffer_put_cstring(r, "Invalid forwarding request"); 673 return 0; 674 } 675 if (fwd.listen_port >= 65536) { 676 logit("%s: invalid listen port %u", __func__, 677 fwd.listen_port); 678 goto invalid; 679 } 680 if (fwd.connect_port >= 65536 || (ftype != MUX_FWD_DYNAMIC && 681 ftype != MUX_FWD_REMOTE && fwd.connect_port == 0)) { 682 logit("%s: invalid connect port %u", __func__, 683 fwd.connect_port); 684 goto invalid; 685 } 686 if (ftype != MUX_FWD_DYNAMIC && fwd.connect_host == NULL) { 687 logit("%s: missing connect host", __func__); 688 goto invalid; 689 } 690 691 /* Skip forwards that have already been requested */ 692 switch (ftype) { 693 case MUX_FWD_LOCAL: 694 case MUX_FWD_DYNAMIC: 695 for (i = 0; i < options.num_local_forwards; i++) { 696 if (compare_forward(&fwd, 697 options.local_forwards + i)) { 698 exists: 699 debug2("%s: found existing forwarding", 700 __func__); 701 buffer_put_int(r, MUX_S_OK); 702 buffer_put_int(r, rid); 703 goto out; 704 } 705 } 706 break; 707 case MUX_FWD_REMOTE: 708 for (i = 0; i < options.num_remote_forwards; i++) { 709 if (compare_forward(&fwd, 710 options.remote_forwards + i)) { 711 if (fwd.listen_port != 0) 712 goto exists; 713 debug2("%s: found allocated port", 714 __func__); 715 buffer_put_int(r, MUX_S_REMOTE_PORT); 716 buffer_put_int(r, rid); 717 buffer_put_int(r, 718 options.remote_forwards[i].allocated_port); 719 goto out; 720 } 721 } 722 break; 723 } 724 725 if (options.control_master == SSHCTL_MASTER_ASK || 726 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 727 if (!ask_permission("Open %s on %s?", fwd_desc, host)) { 728 debug2("%s: forwarding refused by user", __func__); 729 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 730 buffer_put_int(r, rid); 731 buffer_put_cstring(r, "Permission denied"); 732 goto out; 733 } 734 } 735 736 if (ftype == MUX_FWD_LOCAL || ftype == MUX_FWD_DYNAMIC) { 737 if (!channel_setup_local_fwd_listener(fwd.listen_host, 738 fwd.listen_port, fwd.connect_host, fwd.connect_port, 739 options.gateway_ports)) { 740 fail: 741 logit("slave-requested %s failed", fwd_desc); 742 buffer_put_int(r, MUX_S_FAILURE); 743 buffer_put_int(r, rid); 744 buffer_put_cstring(r, "Port forwarding failed"); 745 goto out; 746 } 747 add_local_forward(&options, &fwd); 748 freefwd = 0; 749 } else { 750 struct mux_channel_confirm_ctx *fctx; 751 752 fwd.handle = channel_request_remote_forwarding(fwd.listen_host, 753 fwd.listen_port, fwd.connect_host, fwd.connect_port); 754 if (fwd.handle < 0) 755 goto fail; 756 add_remote_forward(&options, &fwd); 757 fctx = xcalloc(1, sizeof(*fctx)); 758 fctx->cid = c->self; 759 fctx->rid = rid; 760 fctx->fid = options.num_remote_forwards - 1; 761 client_register_global_confirm(mux_confirm_remote_forward, 762 fctx); 763 freefwd = 0; 764 c->mux_pause = 1; /* wait for mux_confirm_remote_forward */ 765 /* delayed reply in mux_confirm_remote_forward */ 766 goto out; 767 } 768 buffer_put_int(r, MUX_S_OK); 769 buffer_put_int(r, rid); 770 out: 771 free(fwd_desc); 772 if (freefwd) { 773 free(fwd.listen_host); 774 free(fwd.connect_host); 775 } 776 return ret; 777} 778 779static int 780process_mux_close_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r) 781{ 782 Forward fwd, *found_fwd; 783 char *fwd_desc = NULL; 784 const char *error_reason = NULL; 785 u_int ftype; 786 int i, listen_port, ret = 0; 787 u_int lport, cport; 788 789 memset(&fwd, 0, sizeof(fwd)); 790 791 if (buffer_get_int_ret(&ftype, m) != 0 || 792 (fwd.listen_host = buffer_get_string_ret(m, NULL)) == NULL || 793 buffer_get_int_ret(&lport, m) != 0 || 794 (fwd.connect_host = buffer_get_string_ret(m, NULL)) == NULL || 795 buffer_get_int_ret(&cport, m) != 0 || 796 lport > 65535 || cport > 65535) { 797 error("%s: malformed message", __func__); 798 ret = -1; 799 goto out; 800 } 801 fwd.listen_port = lport; 802 fwd.connect_port = cport; 803 804 if (*fwd.listen_host == '\0') { 805 free(fwd.listen_host); 806 fwd.listen_host = NULL; 807 } 808 if (*fwd.connect_host == '\0') { 809 free(fwd.connect_host); 810 fwd.connect_host = NULL; 811 } 812 813 debug2("%s: channel %d: request cancel %s", __func__, c->self, 814 (fwd_desc = format_forward(ftype, &fwd))); 815 816 /* make sure this has been requested */ 817 found_fwd = NULL; 818 switch (ftype) { 819 case MUX_FWD_LOCAL: 820 case MUX_FWD_DYNAMIC: 821 for (i = 0; i < options.num_local_forwards; i++) { 822 if (compare_forward(&fwd, 823 options.local_forwards + i)) { 824 found_fwd = options.local_forwards + i; 825 break; 826 } 827 } 828 break; 829 case MUX_FWD_REMOTE: 830 for (i = 0; i < options.num_remote_forwards; i++) { 831 if (compare_forward(&fwd, 832 options.remote_forwards + i)) { 833 found_fwd = options.remote_forwards + i; 834 break; 835 } 836 } 837 break; 838 } 839 840 if (found_fwd == NULL) 841 error_reason = "port not forwarded"; 842 else if (ftype == MUX_FWD_REMOTE) { 843 /* 844 * This shouldn't fail unless we confused the host/port 845 * between options.remote_forwards and permitted_opens. 846 * However, for dynamic allocated listen ports we need 847 * to lookup the actual listen port. 848 */ 849 listen_port = (fwd.listen_port == 0) ? 850 found_fwd->allocated_port : fwd.listen_port; 851 if (channel_request_rforward_cancel(fwd.listen_host, 852 listen_port) == -1) 853 error_reason = "port not in permitted opens"; 854 } else { /* local and dynamic forwards */ 855 /* Ditto */ 856 if (channel_cancel_lport_listener(fwd.listen_host, 857 fwd.listen_port, fwd.connect_port, 858 options.gateway_ports) == -1) 859 error_reason = "port not found"; 860 } 861 862 if (error_reason == NULL) { 863 buffer_put_int(r, MUX_S_OK); 864 buffer_put_int(r, rid); 865 866 free(found_fwd->listen_host); 867 free(found_fwd->connect_host); 868 found_fwd->listen_host = found_fwd->connect_host = NULL; 869 found_fwd->listen_port = found_fwd->connect_port = 0; 870 } else { 871 buffer_put_int(r, MUX_S_FAILURE); 872 buffer_put_int(r, rid); 873 buffer_put_cstring(r, error_reason); 874 } 875 out: 876 free(fwd_desc); 877 free(fwd.listen_host); 878 free(fwd.connect_host); 879 880 return ret; 881} 882 883static int 884process_mux_stdio_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r) 885{ 886 Channel *nc; 887 char *reserved, *chost; 888 u_int cport, i, j; 889 int new_fd[2]; 890 891 chost = reserved = NULL; 892 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL || 893 (chost = buffer_get_string_ret(m, NULL)) == NULL || 894 buffer_get_int_ret(&cport, m) != 0) { 895 free(reserved); 896 free(chost); 897 error("%s: malformed message", __func__); 898 return -1; 899 } 900 free(reserved); 901 902 debug2("%s: channel %d: request stdio fwd to %s:%u", 903 __func__, c->self, chost, cport); 904 905 /* Gather fds from client */ 906 for(i = 0; i < 2; i++) { 907 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) { 908 error("%s: failed to receive fd %d from slave", 909 __func__, i); 910 for (j = 0; j < i; j++) 911 close(new_fd[j]); 912 free(chost); 913 914 /* prepare reply */ 915 buffer_put_int(r, MUX_S_FAILURE); 916 buffer_put_int(r, rid); 917 buffer_put_cstring(r, 918 "did not receive file descriptors"); 919 return -1; 920 } 921 } 922 923 debug3("%s: got fds stdin %d, stdout %d", __func__, 924 new_fd[0], new_fd[1]); 925 926 /* XXX support multiple child sessions in future */ 927 if (c->remote_id != -1) { 928 debug2("%s: session already open", __func__); 929 /* prepare reply */ 930 buffer_put_int(r, MUX_S_FAILURE); 931 buffer_put_int(r, rid); 932 buffer_put_cstring(r, "Multiple sessions not supported"); 933 cleanup: 934 close(new_fd[0]); 935 close(new_fd[1]); 936 free(chost); 937 return 0; 938 } 939 940 if (options.control_master == SSHCTL_MASTER_ASK || 941 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 942 if (!ask_permission("Allow forward to %s:%u? ", 943 chost, cport)) { 944 debug2("%s: stdio fwd refused by user", __func__); 945 /* prepare reply */ 946 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 947 buffer_put_int(r, rid); 948 buffer_put_cstring(r, "Permission denied"); 949 goto cleanup; 950 } 951 } 952 953 /* enable nonblocking unless tty */ 954 if (!isatty(new_fd[0])) 955 set_nonblock(new_fd[0]); 956 if (!isatty(new_fd[1])) 957 set_nonblock(new_fd[1]); 958 959 nc = channel_connect_stdio_fwd(chost, cport, new_fd[0], new_fd[1]); 960 961 nc->ctl_chan = c->self; /* link session -> control channel */ 962 c->remote_id = nc->self; /* link control -> session channel */ 963 964 debug2("%s: channel_new: %d linked to control channel %d", 965 __func__, nc->self, nc->ctl_chan); 966 967 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1); 968 969 /* prepare reply */ 970 /* XXX defer until channel confirmed */ 971 buffer_put_int(r, MUX_S_SESSION_OPENED); 972 buffer_put_int(r, rid); 973 buffer_put_int(r, nc->self); 974 975 return 0; 976} 977 978static int 979process_mux_stop_listening(u_int rid, Channel *c, Buffer *m, Buffer *r) 980{ 981 debug("%s: channel %d: stop listening", __func__, c->self); 982 983 if (options.control_master == SSHCTL_MASTER_ASK || 984 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 985 if (!ask_permission("Disable further multiplexing on shared " 986 "connection to %s? ", host)) { 987 debug2("%s: stop listen refused by user", __func__); 988 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 989 buffer_put_int(r, rid); 990 buffer_put_cstring(r, "Permission denied"); 991 return 0; 992 } 993 } 994 995 if (mux_listener_channel != NULL) { 996 channel_free(mux_listener_channel); 997 client_stop_mux(); 998 free(options.control_path); 999 options.control_path = NULL; 1000 mux_listener_channel = NULL; 1001 muxserver_sock = -1; 1002 } 1003 1004 /* prepare reply */ 1005 buffer_put_int(r, MUX_S_OK); 1006 buffer_put_int(r, rid); 1007 1008 return 0; 1009} 1010 1011/* Channel callbacks fired on read/write from mux slave fd */ 1012static int 1013mux_master_read_cb(Channel *c) 1014{ 1015 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx; 1016 Buffer in, out; 1017 void *ptr; 1018 u_int type, rid, have, i; 1019 int ret = -1; 1020 1021 /* Setup ctx and */ 1022 if (c->mux_ctx == NULL) { 1023 state = xcalloc(1, sizeof(*state)); 1024 c->mux_ctx = state; 1025 channel_register_cleanup(c->self, 1026 mux_master_control_cleanup_cb, 0); 1027 1028 /* Send hello */ 1029 buffer_init(&out); 1030 buffer_put_int(&out, MUX_MSG_HELLO); 1031 buffer_put_int(&out, SSHMUX_VER); 1032 /* no extensions */ 1033 buffer_put_string(&c->output, buffer_ptr(&out), 1034 buffer_len(&out)); 1035 buffer_free(&out); 1036 debug3("%s: channel %d: hello sent", __func__, c->self); 1037 return 0; 1038 } 1039 1040 buffer_init(&in); 1041 buffer_init(&out); 1042 1043 /* Channel code ensures that we receive whole packets */ 1044 if ((ptr = buffer_get_string_ptr_ret(&c->input, &have)) == NULL) { 1045 malf: 1046 error("%s: malformed message", __func__); 1047 goto out; 1048 } 1049 buffer_append(&in, ptr, have); 1050 1051 if (buffer_get_int_ret(&type, &in) != 0) 1052 goto malf; 1053 debug3("%s: channel %d packet type 0x%08x len %u", 1054 __func__, c->self, type, buffer_len(&in)); 1055 1056 if (type == MUX_MSG_HELLO) 1057 rid = 0; 1058 else { 1059 if (!state->hello_rcvd) { 1060 error("%s: expected MUX_MSG_HELLO(0x%08x), " 1061 "received 0x%08x", __func__, MUX_MSG_HELLO, type); 1062 goto out; 1063 } 1064 if (buffer_get_int_ret(&rid, &in) != 0) 1065 goto malf; 1066 } 1067 1068 for (i = 0; mux_master_handlers[i].handler != NULL; i++) { 1069 if (type == mux_master_handlers[i].type) { 1070 ret = mux_master_handlers[i].handler(rid, c, &in, &out); 1071 break; 1072 } 1073 } 1074 if (mux_master_handlers[i].handler == NULL) { 1075 error("%s: unsupported mux message 0x%08x", __func__, type); 1076 buffer_put_int(&out, MUX_S_FAILURE); 1077 buffer_put_int(&out, rid); 1078 buffer_put_cstring(&out, "unsupported request"); 1079 ret = 0; 1080 } 1081 /* Enqueue reply packet */ 1082 if (buffer_len(&out) != 0) { 1083 buffer_put_string(&c->output, buffer_ptr(&out), 1084 buffer_len(&out)); 1085 } 1086 out: 1087 buffer_free(&in); 1088 buffer_free(&out); 1089 return ret; 1090} 1091 1092void 1093mux_exit_message(Channel *c, int exitval) 1094{ 1095 Buffer m; 1096 Channel *mux_chan; 1097 1098 debug3("%s: channel %d: exit message, exitval %d", __func__, c->self, 1099 exitval); 1100 1101 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL) 1102 fatal("%s: channel %d missing mux channel %d", 1103 __func__, c->self, c->ctl_chan); 1104 1105 /* Append exit message packet to control socket output queue */ 1106 buffer_init(&m); 1107 buffer_put_int(&m, MUX_S_EXIT_MESSAGE); 1108 buffer_put_int(&m, c->self); 1109 buffer_put_int(&m, exitval); 1110 1111 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m)); 1112 buffer_free(&m); 1113} 1114 1115void 1116mux_tty_alloc_failed(Channel *c) 1117{ 1118 Buffer m; 1119 Channel *mux_chan; 1120 1121 debug3("%s: channel %d: TTY alloc failed", __func__, c->self); 1122 1123 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL) 1124 fatal("%s: channel %d missing mux channel %d", 1125 __func__, c->self, c->ctl_chan); 1126 1127 /* Append exit message packet to control socket output queue */ 1128 buffer_init(&m); 1129 buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL); 1130 buffer_put_int(&m, c->self); 1131 1132 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m)); 1133 buffer_free(&m); 1134} 1135 1136/* Prepare a mux master to listen on a Unix domain socket. */ 1137void 1138muxserver_listen(void) 1139{ 1140 struct sockaddr_un addr; 1141 socklen_t sun_len; 1142 mode_t old_umask; 1143 char *orig_control_path = options.control_path; 1144 char rbuf[16+1]; 1145 u_int i, r; 1146 1147 if (options.control_path == NULL || 1148 options.control_master == SSHCTL_MASTER_NO) 1149 return; 1150 1151 debug("setting up multiplex master socket"); 1152 1153 /* 1154 * Use a temporary path before listen so we can pseudo-atomically 1155 * establish the listening socket in its final location to avoid 1156 * other processes racing in between bind() and listen() and hitting 1157 * an unready socket. 1158 */ 1159 for (i = 0; i < sizeof(rbuf) - 1; i++) { 1160 r = arc4random_uniform(26+26+10); 1161 rbuf[i] = (r < 26) ? 'a' + r : 1162 (r < 26*2) ? 'A' + r - 26 : 1163 '0' + r - 26 - 26; 1164 } 1165 rbuf[sizeof(rbuf) - 1] = '\0'; 1166 options.control_path = NULL; 1167 xasprintf(&options.control_path, "%s.%s", orig_control_path, rbuf); 1168 debug3("%s: temporary control path %s", __func__, options.control_path); 1169 1170 memset(&addr, '\0', sizeof(addr)); 1171 addr.sun_family = AF_UNIX; 1172 sun_len = offsetof(struct sockaddr_un, sun_path) + 1173 strlen(options.control_path) + 1; 1174 1175 if (strlcpy(addr.sun_path, options.control_path, 1176 sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) { 1177 error("ControlPath \"%s\" too long for Unix domain socket", 1178 options.control_path); 1179 goto disable_mux_master; 1180 } 1181 1182 if ((muxserver_sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) 1183 fatal("%s socket(): %s", __func__, strerror(errno)); 1184 1185 old_umask = umask(0177); 1186 if (bind(muxserver_sock, (struct sockaddr *)&addr, sun_len) == -1) { 1187 if (errno == EINVAL || errno == EADDRINUSE) { 1188 error("ControlSocket %s already exists, " 1189 "disabling multiplexing", options.control_path); 1190 disable_mux_master: 1191 if (muxserver_sock != -1) { 1192 close(muxserver_sock); 1193 muxserver_sock = -1; 1194 } 1195 free(orig_control_path); 1196 free(options.control_path); 1197 options.control_path = NULL; 1198 options.control_master = SSHCTL_MASTER_NO; 1199 return; 1200 } else 1201 fatal("%s bind(): %s", __func__, strerror(errno)); 1202 } 1203 umask(old_umask); 1204 1205 if (listen(muxserver_sock, 64) == -1) 1206 fatal("%s listen(): %s", __func__, strerror(errno)); 1207 1208 /* Now atomically "move" the mux socket into position */ 1209 if (link(options.control_path, orig_control_path) != 0) { 1210 if (errno != EEXIST) { 1211 fatal("%s: link mux listener %s => %s: %s", __func__, 1212 options.control_path, orig_control_path, 1213 strerror(errno)); 1214 } 1215 error("ControlSocket %s already exists, disabling multiplexing", 1216 orig_control_path); 1217 unlink(options.control_path); 1218 goto disable_mux_master; 1219 } 1220 unlink(options.control_path); 1221 free(options.control_path); 1222 options.control_path = orig_control_path; 1223 1224 set_nonblock(muxserver_sock); 1225 1226 mux_listener_channel = channel_new("mux listener", 1227 SSH_CHANNEL_MUX_LISTENER, muxserver_sock, muxserver_sock, -1, 1228 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1229 0, options.control_path, 1); 1230 mux_listener_channel->mux_rcb = mux_master_read_cb; 1231 debug3("%s: mux listener channel %d fd %d", __func__, 1232 mux_listener_channel->self, mux_listener_channel->sock); 1233} 1234 1235/* Callback on open confirmation in mux master for a mux client session. */ 1236static void 1237mux_session_confirm(int id, int success, void *arg) 1238{ 1239 struct mux_session_confirm_ctx *cctx = arg; 1240 const char *display; 1241 Channel *c, *cc; 1242 int i; 1243 Buffer reply; 1244 1245 if (cctx == NULL) 1246 fatal("%s: cctx == NULL", __func__); 1247 if ((c = channel_by_id(id)) == NULL) 1248 fatal("%s: no channel for id %d", __func__, id); 1249 if ((cc = channel_by_id(c->ctl_chan)) == NULL) 1250 fatal("%s: channel %d lacks control channel %d", __func__, 1251 id, c->ctl_chan); 1252 1253 if (!success) { 1254 debug3("%s: sending failure reply", __func__); 1255 /* prepare reply */ 1256 buffer_init(&reply); 1257 buffer_put_int(&reply, MUX_S_FAILURE); 1258 buffer_put_int(&reply, cctx->rid); 1259 buffer_put_cstring(&reply, "Session open refused by peer"); 1260 goto done; 1261 } 1262 1263 display = getenv("DISPLAY"); 1264 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) { 1265 char *proto, *data; 1266 1267 /* Get reasonable local authentication information. */ 1268 client_x11_get_proto(display, options.xauth_location, 1269 options.forward_x11_trusted, options.forward_x11_timeout, 1270 &proto, &data); 1271 /* Request forwarding with authentication spoofing. */ 1272 debug("Requesting X11 forwarding with authentication " 1273 "spoofing."); 1274 x11_request_forwarding_with_spoofing(id, display, proto, 1275 data, 1); 1276 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); 1277 /* XXX exit_on_forward_failure */ 1278 } 1279 1280 if (cctx->want_agent_fwd && options.forward_agent) { 1281 debug("Requesting authentication agent forwarding."); 1282 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1283 packet_send(); 1284 } 1285 1286 client_session2_setup(id, cctx->want_tty, cctx->want_subsys, 1287 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env); 1288 1289 debug3("%s: sending success reply", __func__); 1290 /* prepare reply */ 1291 buffer_init(&reply); 1292 buffer_put_int(&reply, MUX_S_SESSION_OPENED); 1293 buffer_put_int(&reply, cctx->rid); 1294 buffer_put_int(&reply, c->self); 1295 1296 done: 1297 /* Send reply */ 1298 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply)); 1299 buffer_free(&reply); 1300 1301 if (cc->mux_pause <= 0) 1302 fatal("%s: mux_pause %d", __func__, cc->mux_pause); 1303 cc->mux_pause = 0; /* start processing messages again */ 1304 c->open_confirm_ctx = NULL; 1305 buffer_free(&cctx->cmd); 1306 free(cctx->term); 1307 if (cctx->env != NULL) { 1308 for (i = 0; cctx->env[i] != NULL; i++) 1309 free(cctx->env[i]); 1310 free(cctx->env); 1311 } 1312 free(cctx); 1313} 1314 1315/* ** Multiplexing client support */ 1316 1317/* Exit signal handler */ 1318static void 1319control_client_sighandler(int signo) 1320{ 1321 muxclient_terminate = signo; 1322} 1323 1324/* 1325 * Relay signal handler - used to pass some signals from mux client to 1326 * mux master. 1327 */ 1328static void 1329control_client_sigrelay(int signo) 1330{ 1331 int save_errno = errno; 1332 1333 if (muxserver_pid > 1) 1334 kill(muxserver_pid, signo); 1335 1336 errno = save_errno; 1337} 1338 1339static int 1340mux_client_read(int fd, Buffer *b, u_int need) 1341{ 1342 u_int have; 1343 ssize_t len; 1344 u_char *p; 1345 struct pollfd pfd; 1346 1347 pfd.fd = fd; 1348 pfd.events = POLLIN; 1349 p = buffer_append_space(b, need); 1350 for (have = 0; have < need; ) { 1351 if (muxclient_terminate) { 1352 errno = EINTR; 1353 return -1; 1354 } 1355 len = read(fd, p + have, need - have); 1356 if (len < 0) { 1357 switch (errno) { 1358#if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN) 1359 case EWOULDBLOCK: 1360#endif 1361 case EAGAIN: 1362 (void)poll(&pfd, 1, -1); 1363 /* FALLTHROUGH */ 1364 case EINTR: 1365 continue; 1366 default: 1367 return -1; 1368 } 1369 } 1370 if (len == 0) { 1371 errno = EPIPE; 1372 return -1; 1373 } 1374 have += (u_int)len; 1375 } 1376 return 0; 1377} 1378 1379static int 1380mux_client_write_packet(int fd, Buffer *m) 1381{ 1382 Buffer queue; 1383 u_int have, need; 1384 int oerrno, len; 1385 u_char *ptr; 1386 struct pollfd pfd; 1387 1388 pfd.fd = fd; 1389 pfd.events = POLLOUT; 1390 buffer_init(&queue); 1391 buffer_put_string(&queue, buffer_ptr(m), buffer_len(m)); 1392 1393 need = buffer_len(&queue); 1394 ptr = buffer_ptr(&queue); 1395 1396 for (have = 0; have < need; ) { 1397 if (muxclient_terminate) { 1398 buffer_free(&queue); 1399 errno = EINTR; 1400 return -1; 1401 } 1402 len = write(fd, ptr + have, need - have); 1403 if (len < 0) { 1404 switch (errno) { 1405#if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN) 1406 case EWOULDBLOCK: 1407#endif 1408 case EAGAIN: 1409 (void)poll(&pfd, 1, -1); 1410 /* FALLTHROUGH */ 1411 case EINTR: 1412 continue; 1413 default: 1414 oerrno = errno; 1415 buffer_free(&queue); 1416 errno = oerrno; 1417 return -1; 1418 } 1419 } 1420 if (len == 0) { 1421 buffer_free(&queue); 1422 errno = EPIPE; 1423 return -1; 1424 } 1425 have += (u_int)len; 1426 } 1427 buffer_free(&queue); 1428 return 0; 1429} 1430 1431static int 1432mux_client_read_packet(int fd, Buffer *m) 1433{ 1434 Buffer queue; 1435 u_int need, have; 1436 void *ptr; 1437 int oerrno; 1438 1439 buffer_init(&queue); 1440 if (mux_client_read(fd, &queue, 4) != 0) { 1441 if ((oerrno = errno) == EPIPE) 1442 debug3("%s: read header failed: %s", __func__, 1443 strerror(errno)); 1444 buffer_free(&queue); 1445 errno = oerrno; 1446 return -1; 1447 } 1448 need = get_u32(buffer_ptr(&queue)); 1449 if (mux_client_read(fd, &queue, need) != 0) { 1450 oerrno = errno; 1451 debug3("%s: read body failed: %s", __func__, strerror(errno)); 1452 buffer_free(&queue); 1453 errno = oerrno; 1454 return -1; 1455 } 1456 ptr = buffer_get_string_ptr(&queue, &have); 1457 buffer_append(m, ptr, have); 1458 buffer_free(&queue); 1459 return 0; 1460} 1461 1462static int 1463mux_client_hello_exchange(int fd) 1464{ 1465 Buffer m; 1466 u_int type, ver; 1467 1468 buffer_init(&m); 1469 buffer_put_int(&m, MUX_MSG_HELLO); 1470 buffer_put_int(&m, SSHMUX_VER); 1471 /* no extensions */ 1472 1473 if (mux_client_write_packet(fd, &m) != 0) 1474 fatal("%s: write packet: %s", __func__, strerror(errno)); 1475 1476 buffer_clear(&m); 1477 1478 /* Read their HELLO */ 1479 if (mux_client_read_packet(fd, &m) != 0) { 1480 buffer_free(&m); 1481 return -1; 1482 } 1483 1484 type = buffer_get_int(&m); 1485 if (type != MUX_MSG_HELLO) 1486 fatal("%s: expected HELLO (%u) received %u", 1487 __func__, MUX_MSG_HELLO, type); 1488 ver = buffer_get_int(&m); 1489 if (ver != SSHMUX_VER) 1490 fatal("Unsupported multiplexing protocol version %d " 1491 "(expected %d)", ver, SSHMUX_VER); 1492 debug2("%s: master version %u", __func__, ver); 1493 /* No extensions are presently defined */ 1494 while (buffer_len(&m) > 0) { 1495 char *name = buffer_get_string(&m, NULL); 1496 char *value = buffer_get_string(&m, NULL); 1497 1498 debug2("Unrecognised master extension \"%s\"", name); 1499 free(name); 1500 free(value); 1501 } 1502 buffer_free(&m); 1503 return 0; 1504} 1505 1506static u_int 1507mux_client_request_alive(int fd) 1508{ 1509 Buffer m; 1510 char *e; 1511 u_int pid, type, rid; 1512 1513 debug3("%s: entering", __func__); 1514 1515 buffer_init(&m); 1516 buffer_put_int(&m, MUX_C_ALIVE_CHECK); 1517 buffer_put_int(&m, muxclient_request_id); 1518 1519 if (mux_client_write_packet(fd, &m) != 0) 1520 fatal("%s: write packet: %s", __func__, strerror(errno)); 1521 1522 buffer_clear(&m); 1523 1524 /* Read their reply */ 1525 if (mux_client_read_packet(fd, &m) != 0) { 1526 buffer_free(&m); 1527 return 0; 1528 } 1529 1530 type = buffer_get_int(&m); 1531 if (type != MUX_S_ALIVE) { 1532 e = buffer_get_string(&m, NULL); 1533 fatal("%s: master returned error: %s", __func__, e); 1534 } 1535 1536 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1537 fatal("%s: out of sequence reply: my id %u theirs %u", 1538 __func__, muxclient_request_id, rid); 1539 pid = buffer_get_int(&m); 1540 buffer_free(&m); 1541 1542 debug3("%s: done pid = %u", __func__, pid); 1543 1544 muxclient_request_id++; 1545 1546 return pid; 1547} 1548 1549static void 1550mux_client_request_terminate(int fd) 1551{ 1552 Buffer m; 1553 char *e; 1554 u_int type, rid; 1555 1556 debug3("%s: entering", __func__); 1557 1558 buffer_init(&m); 1559 buffer_put_int(&m, MUX_C_TERMINATE); 1560 buffer_put_int(&m, muxclient_request_id); 1561 1562 if (mux_client_write_packet(fd, &m) != 0) 1563 fatal("%s: write packet: %s", __func__, strerror(errno)); 1564 1565 buffer_clear(&m); 1566 1567 /* Read their reply */ 1568 if (mux_client_read_packet(fd, &m) != 0) { 1569 /* Remote end exited already */ 1570 if (errno == EPIPE) { 1571 buffer_free(&m); 1572 return; 1573 } 1574 fatal("%s: read from master failed: %s", 1575 __func__, strerror(errno)); 1576 } 1577 1578 type = buffer_get_int(&m); 1579 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1580 fatal("%s: out of sequence reply: my id %u theirs %u", 1581 __func__, muxclient_request_id, rid); 1582 switch (type) { 1583 case MUX_S_OK: 1584 break; 1585 case MUX_S_PERMISSION_DENIED: 1586 e = buffer_get_string(&m, NULL); 1587 fatal("Master refused termination request: %s", e); 1588 case MUX_S_FAILURE: 1589 e = buffer_get_string(&m, NULL); 1590 fatal("%s: termination request failed: %s", __func__, e); 1591 default: 1592 fatal("%s: unexpected response from master 0x%08x", 1593 __func__, type); 1594 } 1595 buffer_free(&m); 1596 muxclient_request_id++; 1597} 1598 1599static int 1600mux_client_forward(int fd, int cancel_flag, u_int ftype, Forward *fwd) 1601{ 1602 Buffer m; 1603 char *e, *fwd_desc; 1604 u_int type, rid; 1605 1606 fwd_desc = format_forward(ftype, fwd); 1607 debug("Requesting %s %s", 1608 cancel_flag ? "cancellation of" : "forwarding of", fwd_desc); 1609 free(fwd_desc); 1610 1611 buffer_init(&m); 1612 buffer_put_int(&m, cancel_flag ? MUX_C_CLOSE_FWD : MUX_C_OPEN_FWD); 1613 buffer_put_int(&m, muxclient_request_id); 1614 buffer_put_int(&m, ftype); 1615 buffer_put_cstring(&m, 1616 fwd->listen_host == NULL ? "" : fwd->listen_host); 1617 buffer_put_int(&m, fwd->listen_port); 1618 buffer_put_cstring(&m, 1619 fwd->connect_host == NULL ? "" : fwd->connect_host); 1620 buffer_put_int(&m, fwd->connect_port); 1621 1622 if (mux_client_write_packet(fd, &m) != 0) 1623 fatal("%s: write packet: %s", __func__, strerror(errno)); 1624 1625 buffer_clear(&m); 1626 1627 /* Read their reply */ 1628 if (mux_client_read_packet(fd, &m) != 0) { 1629 buffer_free(&m); 1630 return -1; 1631 } 1632 1633 type = buffer_get_int(&m); 1634 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1635 fatal("%s: out of sequence reply: my id %u theirs %u", 1636 __func__, muxclient_request_id, rid); 1637 switch (type) { 1638 case MUX_S_OK: 1639 break; 1640 case MUX_S_REMOTE_PORT: 1641 if (cancel_flag) 1642 fatal("%s: got MUX_S_REMOTE_PORT for cancel", __func__); 1643 fwd->allocated_port = buffer_get_int(&m); 1644 logit("Allocated port %u for remote forward to %s:%d", 1645 fwd->allocated_port, 1646 fwd->connect_host ? fwd->connect_host : "", 1647 fwd->connect_port); 1648 if (muxclient_command == SSHMUX_COMMAND_FORWARD) 1649 fprintf(stdout, "%u\n", fwd->allocated_port); 1650 break; 1651 case MUX_S_PERMISSION_DENIED: 1652 e = buffer_get_string(&m, NULL); 1653 buffer_free(&m); 1654 error("Master refused forwarding request: %s", e); 1655 return -1; 1656 case MUX_S_FAILURE: 1657 e = buffer_get_string(&m, NULL); 1658 buffer_free(&m); 1659 error("%s: forwarding request failed: %s", __func__, e); 1660 return -1; 1661 default: 1662 fatal("%s: unexpected response from master 0x%08x", 1663 __func__, type); 1664 } 1665 buffer_free(&m); 1666 1667 muxclient_request_id++; 1668 return 0; 1669} 1670 1671static int 1672mux_client_forwards(int fd, int cancel_flag) 1673{ 1674 int i, ret = 0; 1675 1676 debug3("%s: %s forwardings: %d local, %d remote", __func__, 1677 cancel_flag ? "cancel" : "request", 1678 options.num_local_forwards, options.num_remote_forwards); 1679 1680 /* XXX ExitOnForwardingFailure */ 1681 for (i = 0; i < options.num_local_forwards; i++) { 1682 if (mux_client_forward(fd, cancel_flag, 1683 options.local_forwards[i].connect_port == 0 ? 1684 MUX_FWD_DYNAMIC : MUX_FWD_LOCAL, 1685 options.local_forwards + i) != 0) 1686 ret = -1; 1687 } 1688 for (i = 0; i < options.num_remote_forwards; i++) { 1689 if (mux_client_forward(fd, cancel_flag, MUX_FWD_REMOTE, 1690 options.remote_forwards + i) != 0) 1691 ret = -1; 1692 } 1693 return ret; 1694} 1695 1696static int 1697mux_client_request_session(int fd) 1698{ 1699 Buffer m; 1700 char *e, *term; 1701 u_int i, rid, sid, esid, exitval, type, exitval_seen; 1702 extern char **environ; 1703 int devnull, rawmode; 1704 1705 debug3("%s: entering", __func__); 1706 1707 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) { 1708 error("%s: master alive request failed", __func__); 1709 return -1; 1710 } 1711 1712 signal(SIGPIPE, SIG_IGN); 1713 1714 if (stdin_null_flag) { 1715 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1716 fatal("open(/dev/null): %s", strerror(errno)); 1717 if (dup2(devnull, STDIN_FILENO) == -1) 1718 fatal("dup2: %s", strerror(errno)); 1719 if (devnull > STDERR_FILENO) 1720 close(devnull); 1721 } 1722 1723 term = getenv("TERM"); 1724 1725 buffer_init(&m); 1726 buffer_put_int(&m, MUX_C_NEW_SESSION); 1727 buffer_put_int(&m, muxclient_request_id); 1728 buffer_put_cstring(&m, ""); /* reserved */ 1729 buffer_put_int(&m, tty_flag); 1730 buffer_put_int(&m, options.forward_x11); 1731 buffer_put_int(&m, options.forward_agent); 1732 buffer_put_int(&m, subsystem_flag); 1733 buffer_put_int(&m, options.escape_char == SSH_ESCAPECHAR_NONE ? 1734 0xffffffff : (u_int)options.escape_char); 1735 buffer_put_cstring(&m, term == NULL ? "" : term); 1736 buffer_put_string(&m, buffer_ptr(&command), buffer_len(&command)); 1737 1738 if (options.num_send_env > 0 && environ != NULL) { 1739 /* Pass environment */ 1740 for (i = 0; environ[i] != NULL; i++) { 1741 if (env_permitted(environ[i])) { 1742 buffer_put_cstring(&m, environ[i]); 1743 } 1744 } 1745 } 1746 1747 if (mux_client_write_packet(fd, &m) != 0) 1748 fatal("%s: write packet: %s", __func__, strerror(errno)); 1749 1750 /* Send the stdio file descriptors */ 1751 if (mm_send_fd(fd, STDIN_FILENO) == -1 || 1752 mm_send_fd(fd, STDOUT_FILENO) == -1 || 1753 mm_send_fd(fd, STDERR_FILENO) == -1) 1754 fatal("%s: send fds failed", __func__); 1755 1756 debug3("%s: session request sent", __func__); 1757 1758 /* Read their reply */ 1759 buffer_clear(&m); 1760 if (mux_client_read_packet(fd, &m) != 0) { 1761 error("%s: read from master failed: %s", 1762 __func__, strerror(errno)); 1763 buffer_free(&m); 1764 return -1; 1765 } 1766 1767 type = buffer_get_int(&m); 1768 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1769 fatal("%s: out of sequence reply: my id %u theirs %u", 1770 __func__, muxclient_request_id, rid); 1771 switch (type) { 1772 case MUX_S_SESSION_OPENED: 1773 sid = buffer_get_int(&m); 1774 debug("%s: master session id: %u", __func__, sid); 1775 break; 1776 case MUX_S_PERMISSION_DENIED: 1777 e = buffer_get_string(&m, NULL); 1778 buffer_free(&m); 1779 error("Master refused session request: %s", e); 1780 return -1; 1781 case MUX_S_FAILURE: 1782 e = buffer_get_string(&m, NULL); 1783 buffer_free(&m); 1784 error("%s: session request failed: %s", __func__, e); 1785 return -1; 1786 default: 1787 buffer_free(&m); 1788 error("%s: unexpected response from master 0x%08x", 1789 __func__, type); 1790 return -1; 1791 } 1792 muxclient_request_id++; 1793 1794 signal(SIGHUP, control_client_sighandler); 1795 signal(SIGINT, control_client_sighandler); 1796 signal(SIGTERM, control_client_sighandler); 1797 signal(SIGWINCH, control_client_sigrelay); 1798 1799 rawmode = tty_flag; 1800 if (tty_flag) 1801 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1802 1803 /* 1804 * Stick around until the controlee closes the client_fd. 1805 * Before it does, it is expected to write an exit message. 1806 * This process must read the value and wait for the closure of 1807 * the client_fd; if this one closes early, the multiplex master will 1808 * terminate early too (possibly losing data). 1809 */ 1810 for (exitval = 255, exitval_seen = 0;;) { 1811 buffer_clear(&m); 1812 if (mux_client_read_packet(fd, &m) != 0) 1813 break; 1814 type = buffer_get_int(&m); 1815 switch (type) { 1816 case MUX_S_TTY_ALLOC_FAIL: 1817 if ((esid = buffer_get_int(&m)) != sid) 1818 fatal("%s: tty alloc fail on unknown session: " 1819 "my id %u theirs %u", 1820 __func__, sid, esid); 1821 leave_raw_mode(options.request_tty == 1822 REQUEST_TTY_FORCE); 1823 rawmode = 0; 1824 continue; 1825 case MUX_S_EXIT_MESSAGE: 1826 if ((esid = buffer_get_int(&m)) != sid) 1827 fatal("%s: exit on unknown session: " 1828 "my id %u theirs %u", 1829 __func__, sid, esid); 1830 if (exitval_seen) 1831 fatal("%s: exitval sent twice", __func__); 1832 exitval = buffer_get_int(&m); 1833 exitval_seen = 1; 1834 continue; 1835 default: 1836 e = buffer_get_string(&m, NULL); 1837 fatal("%s: master returned error: %s", __func__, e); 1838 } 1839 } 1840 1841 close(fd); 1842 if (rawmode) 1843 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1844 1845 if (muxclient_terminate) { 1846 debug2("Exiting on signal %ld", (long)muxclient_terminate); 1847 exitval = 255; 1848 } else if (!exitval_seen) { 1849 debug2("Control master terminated unexpectedly"); 1850 exitval = 255; 1851 } else 1852 debug2("Received exit status from master %d", exitval); 1853 1854 if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET) 1855 fprintf(stderr, "Shared connection to %s closed.\r\n", host); 1856 1857 exit(exitval); 1858} 1859 1860static int 1861mux_client_request_stdio_fwd(int fd) 1862{ 1863 Buffer m; 1864 char *e; 1865 u_int type, rid, sid; 1866 int devnull; 1867 1868 debug3("%s: entering", __func__); 1869 1870 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) { 1871 error("%s: master alive request failed", __func__); 1872 return -1; 1873 } 1874 1875 signal(SIGPIPE, SIG_IGN); 1876 1877 if (stdin_null_flag) { 1878 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1879 fatal("open(/dev/null): %s", strerror(errno)); 1880 if (dup2(devnull, STDIN_FILENO) == -1) 1881 fatal("dup2: %s", strerror(errno)); 1882 if (devnull > STDERR_FILENO) 1883 close(devnull); 1884 } 1885 1886 buffer_init(&m); 1887 buffer_put_int(&m, MUX_C_NEW_STDIO_FWD); 1888 buffer_put_int(&m, muxclient_request_id); 1889 buffer_put_cstring(&m, ""); /* reserved */ 1890 buffer_put_cstring(&m, stdio_forward_host); 1891 buffer_put_int(&m, stdio_forward_port); 1892 1893 if (mux_client_write_packet(fd, &m) != 0) 1894 fatal("%s: write packet: %s", __func__, strerror(errno)); 1895 1896 /* Send the stdio file descriptors */ 1897 if (mm_send_fd(fd, STDIN_FILENO) == -1 || 1898 mm_send_fd(fd, STDOUT_FILENO) == -1) 1899 fatal("%s: send fds failed", __func__); 1900 1901 debug3("%s: stdio forward request sent", __func__); 1902 1903 /* Read their reply */ 1904 buffer_clear(&m); 1905 1906 if (mux_client_read_packet(fd, &m) != 0) { 1907 error("%s: read from master failed: %s", 1908 __func__, strerror(errno)); 1909 buffer_free(&m); 1910 return -1; 1911 } 1912 1913 type = buffer_get_int(&m); 1914 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1915 fatal("%s: out of sequence reply: my id %u theirs %u", 1916 __func__, muxclient_request_id, rid); 1917 switch (type) { 1918 case MUX_S_SESSION_OPENED: 1919 sid = buffer_get_int(&m); 1920 debug("%s: master session id: %u", __func__, sid); 1921 break; 1922 case MUX_S_PERMISSION_DENIED: 1923 e = buffer_get_string(&m, NULL); 1924 buffer_free(&m); 1925 fatal("Master refused stdio forwarding request: %s", e); 1926 case MUX_S_FAILURE: 1927 e = buffer_get_string(&m, NULL); 1928 buffer_free(&m); 1929 fatal("%s: stdio forwarding request failed: %s", __func__, e); 1930 default: 1931 buffer_free(&m); 1932 error("%s: unexpected response from master 0x%08x", 1933 __func__, type); 1934 return -1; 1935 } 1936 muxclient_request_id++; 1937 1938 signal(SIGHUP, control_client_sighandler); 1939 signal(SIGINT, control_client_sighandler); 1940 signal(SIGTERM, control_client_sighandler); 1941 signal(SIGWINCH, control_client_sigrelay); 1942 1943 /* 1944 * Stick around until the controlee closes the client_fd. 1945 */ 1946 buffer_clear(&m); 1947 if (mux_client_read_packet(fd, &m) != 0) { 1948 if (errno == EPIPE || 1949 (errno == EINTR && muxclient_terminate != 0)) 1950 return 0; 1951 fatal("%s: mux_client_read_packet: %s", 1952 __func__, strerror(errno)); 1953 } 1954 fatal("%s: master returned unexpected message %u", __func__, type); 1955} 1956 1957static void 1958mux_client_request_stop_listening(int fd) 1959{ 1960 Buffer m; 1961 char *e; 1962 u_int type, rid; 1963 1964 debug3("%s: entering", __func__); 1965 1966 buffer_init(&m); 1967 buffer_put_int(&m, MUX_C_STOP_LISTENING); 1968 buffer_put_int(&m, muxclient_request_id); 1969 1970 if (mux_client_write_packet(fd, &m) != 0) 1971 fatal("%s: write packet: %s", __func__, strerror(errno)); 1972 1973 buffer_clear(&m); 1974 1975 /* Read their reply */ 1976 if (mux_client_read_packet(fd, &m) != 0) 1977 fatal("%s: read from master failed: %s", 1978 __func__, strerror(errno)); 1979 1980 type = buffer_get_int(&m); 1981 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1982 fatal("%s: out of sequence reply: my id %u theirs %u", 1983 __func__, muxclient_request_id, rid); 1984 switch (type) { 1985 case MUX_S_OK: 1986 break; 1987 case MUX_S_PERMISSION_DENIED: 1988 e = buffer_get_string(&m, NULL); 1989 fatal("Master refused stop listening request: %s", e); 1990 case MUX_S_FAILURE: 1991 e = buffer_get_string(&m, NULL); 1992 fatal("%s: stop listening request failed: %s", __func__, e); 1993 default: 1994 fatal("%s: unexpected response from master 0x%08x", 1995 __func__, type); 1996 } 1997 buffer_free(&m); 1998 muxclient_request_id++; 1999} 2000 2001/* Multiplex client main loop. */ 2002void 2003muxclient(const char *path) 2004{ 2005 struct sockaddr_un addr; 2006 socklen_t sun_len; 2007 int sock; 2008 u_int pid; 2009 2010 if (muxclient_command == 0) { 2011 if (stdio_forward_host != NULL) 2012 muxclient_command = SSHMUX_COMMAND_STDIO_FWD; 2013 else 2014 muxclient_command = SSHMUX_COMMAND_OPEN; 2015 } 2016 2017 switch (options.control_master) { 2018 case SSHCTL_MASTER_AUTO: 2019 case SSHCTL_MASTER_AUTO_ASK: 2020 debug("auto-mux: Trying existing master"); 2021 /* FALLTHROUGH */ 2022 case SSHCTL_MASTER_NO: 2023 break; 2024 default: 2025 return; 2026 } 2027 2028 memset(&addr, '\0', sizeof(addr)); 2029 addr.sun_family = AF_UNIX; 2030 sun_len = offsetof(struct sockaddr_un, sun_path) + 2031 strlen(path) + 1; 2032 2033 if (strlcpy(addr.sun_path, path, 2034 sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) 2035 fatal("ControlPath too long"); 2036 2037 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) 2038 fatal("%s socket(): %s", __func__, strerror(errno)); 2039 2040 if (connect(sock, (struct sockaddr *)&addr, sun_len) == -1) { 2041 switch (muxclient_command) { 2042 case SSHMUX_COMMAND_OPEN: 2043 case SSHMUX_COMMAND_STDIO_FWD: 2044 break; 2045 default: 2046 fatal("Control socket connect(%.100s): %s", path, 2047 strerror(errno)); 2048 } 2049 if (errno == ECONNREFUSED && 2050 options.control_master != SSHCTL_MASTER_NO) { 2051 debug("Stale control socket %.100s, unlinking", path); 2052 unlink(path); 2053 } else if (errno == ENOENT) { 2054 debug("Control socket \"%.100s\" does not exist", path); 2055 } else { 2056 error("Control socket connect(%.100s): %s", path, 2057 strerror(errno)); 2058 } 2059 close(sock); 2060 return; 2061 } 2062 set_nonblock(sock); 2063 2064 if (mux_client_hello_exchange(sock) != 0) { 2065 error("%s: master hello exchange failed", __func__); 2066 close(sock); 2067 return; 2068 } 2069 2070 switch (muxclient_command) { 2071 case SSHMUX_COMMAND_ALIVE_CHECK: 2072 if ((pid = mux_client_request_alive(sock)) == 0) 2073 fatal("%s: master alive check failed", __func__); 2074 fprintf(stderr, "Master running (pid=%d)\r\n", pid); 2075 exit(0); 2076 case SSHMUX_COMMAND_TERMINATE: 2077 mux_client_request_terminate(sock); 2078 fprintf(stderr, "Exit request sent.\r\n"); 2079 exit(0); 2080 case SSHMUX_COMMAND_FORWARD: 2081 if (mux_client_forwards(sock, 0) != 0) 2082 fatal("%s: master forward request failed", __func__); 2083 exit(0); 2084 case SSHMUX_COMMAND_OPEN: 2085 if (mux_client_forwards(sock, 0) != 0) { 2086 error("%s: master forward request failed", __func__); 2087 return; 2088 } 2089 mux_client_request_session(sock); 2090 return; 2091 case SSHMUX_COMMAND_STDIO_FWD: 2092 mux_client_request_stdio_fwd(sock); 2093 exit(0); 2094 case SSHMUX_COMMAND_STOP: 2095 mux_client_request_stop_listening(sock); 2096 fprintf(stderr, "Stop listening request sent.\r\n"); 2097 exit(0); 2098 case SSHMUX_COMMAND_CANCEL_FWD: 2099 if (mux_client_forwards(sock, 1) != 0) 2100 error("%s: master cancel forward request failed", 2101 __func__); 2102 exit(0); 2103 default: 2104 fatal("unrecognised muxclient_command %d", muxclient_command); 2105 } 2106} 2107