1 /* $OpenBSD: mux.c,v 1.36 2012/07/06 01:37:21 djm Exp $ */ 2 /* 3 * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 /* ssh session multiplexing support */ 19 20 /* 21 * TODO: 22 * - Better signalling from master to slave, especially passing of 23 * error messages 24 * - Better fall-back from mux slave error to new connection. 25 * - ExitOnForwardingFailure 26 * - Maybe extension mechanisms for multi-X11/multi-agent forwarding 27 * - Support ~^Z in mux slaves. 28 * - Inspect or control sessions in master. 29 * - If we ever support the "signal" channel request, send signals on 30 * sessions in master. 31 */ 32 33 #include "includes.h" 34 35 #include <sys/types.h> 36 #include <sys/param.h> 37 #include <sys/stat.h> 38 #include <sys/socket.h> 39 #include <sys/un.h> 40 41 #include <errno.h> 42 #include <fcntl.h> 43 #include <signal.h> 44 #include <stdarg.h> 45 #include <stddef.h> 46 #include <stdlib.h> 47 #include <stdio.h> 48 #include <string.h> 49 #include <unistd.h> 50 #ifdef HAVE_PATHS_H 51 #include <paths.h> 52 #endif 53 54 #ifdef HAVE_POLL_H 55 #include <poll.h> 56 #else 57 # ifdef HAVE_SYS_POLL_H 58 # include <sys/poll.h> 59 # endif 60 #endif 61 62 #ifdef HAVE_UTIL_H 63 # include <util.h> 64 #endif 65 66 #ifdef HAVE_LIBUTIL_H 67 # include <libutil.h> 68 #endif 69 70 #include "openbsd-compat/sys-queue.h" 71 #include "xmalloc.h" 72 #include "log.h" 73 #include "ssh.h" 74 #include "ssh2.h" 75 #include "pathnames.h" 76 #include "misc.h" 77 #include "match.h" 78 #include "buffer.h" 79 #include "channels.h" 80 #include "msg.h" 81 #include "packet.h" 82 #include "monitor_fdpass.h" 83 #include "sshpty.h" 84 #include "key.h" 85 #include "readconf.h" 86 #include "clientloop.h" 87 88 /* from ssh.c */ 89 extern int tty_flag; 90 extern Options options; 91 extern int stdin_null_flag; 92 extern char *host; 93 extern int subsystem_flag; 94 extern Buffer command; 95 extern volatile sig_atomic_t quit_pending; 96 extern char *stdio_forward_host; 97 extern int stdio_forward_port; 98 99 /* Context for session open confirmation callback */ 100 struct mux_session_confirm_ctx { 101 u_int want_tty; 102 u_int want_subsys; 103 u_int want_x_fwd; 104 u_int want_agent_fwd; 105 Buffer cmd; 106 char *term; 107 struct termios tio; 108 char **env; 109 u_int rid; 110 }; 111 112 /* Context for global channel callback */ 113 struct mux_channel_confirm_ctx { 114 u_int cid; /* channel id */ 115 u_int rid; /* request id */ 116 int fid; /* forward id */ 117 }; 118 119 /* fd to control socket */ 120 int muxserver_sock = -1; 121 122 /* client request id */ 123 u_int muxclient_request_id = 0; 124 125 /* Multiplexing control command */ 126 u_int muxclient_command = 0; 127 128 /* Set when signalled. */ 129 static volatile sig_atomic_t muxclient_terminate = 0; 130 131 /* PID of multiplex server */ 132 static u_int muxserver_pid = 0; 133 134 static Channel *mux_listener_channel = NULL; 135 136 struct mux_master_state { 137 int hello_rcvd; 138 }; 139 140 /* mux protocol messages */ 141 #define MUX_MSG_HELLO 0x00000001 142 #define MUX_C_NEW_SESSION 0x10000002 143 #define MUX_C_ALIVE_CHECK 0x10000004 144 #define MUX_C_TERMINATE 0x10000005 145 #define MUX_C_OPEN_FWD 0x10000006 146 #define MUX_C_CLOSE_FWD 0x10000007 147 #define MUX_C_NEW_STDIO_FWD 0x10000008 148 #define MUX_C_STOP_LISTENING 0x10000009 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 157 158 /* type codes for MUX_C_OPEN_FWD and MUX_C_CLOSE_FWD */ 159 #define MUX_FWD_LOCAL 1 160 #define MUX_FWD_REMOTE 2 161 #define MUX_FWD_DYNAMIC 3 162 163 static void mux_session_confirm(int, int, void *); 164 165 static int process_mux_master_hello(u_int, Channel *, Buffer *, Buffer *); 166 static int process_mux_new_session(u_int, Channel *, Buffer *, Buffer *); 167 static int process_mux_alive_check(u_int, Channel *, Buffer *, Buffer *); 168 static int process_mux_terminate(u_int, Channel *, Buffer *, Buffer *); 169 static int process_mux_open_fwd(u_int, Channel *, Buffer *, Buffer *); 170 static int process_mux_close_fwd(u_int, Channel *, Buffer *, Buffer *); 171 static int process_mux_stdio_fwd(u_int, Channel *, Buffer *, Buffer *); 172 static int process_mux_stop_listening(u_int, Channel *, Buffer *, Buffer *); 173 174 static const struct { 175 u_int type; 176 int (*handler)(u_int, Channel *, Buffer *, Buffer *); 177 } mux_master_handlers[] = { 178 { MUX_MSG_HELLO, process_mux_master_hello }, 179 { MUX_C_NEW_SESSION, process_mux_new_session }, 180 { MUX_C_ALIVE_CHECK, process_mux_alive_check }, 181 { MUX_C_TERMINATE, process_mux_terminate }, 182 { MUX_C_OPEN_FWD, process_mux_open_fwd }, 183 { MUX_C_CLOSE_FWD, process_mux_close_fwd }, 184 { MUX_C_NEW_STDIO_FWD, process_mux_stdio_fwd }, 185 { MUX_C_STOP_LISTENING, process_mux_stop_listening }, 186 { 0, NULL } 187 }; 188 189 /* Cleanup callback fired on closure of mux slave _session_ channel */ 190 /* ARGSUSED */ 191 static void 192 mux_master_session_cleanup_cb(int cid, void *unused) 193 { 194 Channel *cc, *c = channel_by_id(cid); 195 196 debug3("%s: entering for channel %d", __func__, cid); 197 if (c == NULL) 198 fatal("%s: channel_by_id(%i) == NULL", __func__, cid); 199 if (c->ctl_chan != -1) { 200 if ((cc = channel_by_id(c->ctl_chan)) == NULL) 201 fatal("%s: channel %d missing control channel %d", 202 __func__, c->self, c->ctl_chan); 203 c->ctl_chan = -1; 204 cc->remote_id = -1; 205 chan_rcvd_oclose(cc); 206 } 207 channel_cancel_cleanup(c->self); 208 } 209 210 /* Cleanup callback fired on closure of mux slave _control_ channel */ 211 /* ARGSUSED */ 212 static void 213 mux_master_control_cleanup_cb(int cid, void *unused) 214 { 215 Channel *sc, *c = channel_by_id(cid); 216 217 debug3("%s: entering for channel %d", __func__, cid); 218 if (c == NULL) 219 fatal("%s: channel_by_id(%i) == NULL", __func__, cid); 220 if (c->remote_id != -1) { 221 if ((sc = channel_by_id(c->remote_id)) == NULL) 222 fatal("%s: channel %d missing session channel %d", 223 __func__, c->self, c->remote_id); 224 c->remote_id = -1; 225 sc->ctl_chan = -1; 226 if (sc->type != SSH_CHANNEL_OPEN) { 227 debug2("%s: channel %d: not open", __func__, sc->self); 228 chan_mark_dead(sc); 229 } else { 230 if (sc->istate == CHAN_INPUT_OPEN) 231 chan_read_failed(sc); 232 if (sc->ostate == CHAN_OUTPUT_OPEN) 233 chan_write_failed(sc); 234 } 235 } 236 channel_cancel_cleanup(c->self); 237 } 238 239 /* Check mux client environment variables before passing them to mux master. */ 240 static int 241 env_permitted(char *env) 242 { 243 int i, ret; 244 char name[1024], *cp; 245 246 if ((cp = strchr(env, '=')) == NULL || cp == env) 247 return 0; 248 ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env); 249 if (ret <= 0 || (size_t)ret >= sizeof(name)) { 250 error("env_permitted: name '%.100s...' too long", env); 251 return 0; 252 } 253 254 for (i = 0; i < options.num_send_env; i++) 255 if (match_pattern(name, options.send_env[i])) 256 return 1; 257 258 return 0; 259 } 260 261 /* Mux master protocol message handlers */ 262 263 static int 264 process_mux_master_hello(u_int rid, Channel *c, Buffer *m, Buffer *r) 265 { 266 u_int ver; 267 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx; 268 269 if (state == NULL) 270 fatal("%s: channel %d: c->mux_ctx == NULL", __func__, c->self); 271 if (state->hello_rcvd) { 272 error("%s: HELLO received twice", __func__); 273 return -1; 274 } 275 if (buffer_get_int_ret(&ver, m) != 0) { 276 malf: 277 error("%s: malformed message", __func__); 278 return -1; 279 } 280 if (ver != SSHMUX_VER) { 281 error("Unsupported multiplexing protocol version %d " 282 "(expected %d)", ver, SSHMUX_VER); 283 return -1; 284 } 285 debug2("%s: channel %d slave version %u", __func__, c->self, ver); 286 287 /* No extensions are presently defined */ 288 while (buffer_len(m) > 0) { 289 char *name = buffer_get_string_ret(m, NULL); 290 char *value = buffer_get_string_ret(m, NULL); 291 292 if (name == NULL || value == NULL) { 293 if (name != NULL) 294 xfree(name); 295 goto malf; 296 } 297 debug2("Unrecognised slave extension \"%s\"", name); 298 xfree(name); 299 xfree(value); 300 } 301 state->hello_rcvd = 1; 302 return 0; 303 } 304 305 static int 306 process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r) 307 { 308 Channel *nc; 309 struct mux_session_confirm_ctx *cctx; 310 char *reserved, *cmd, *cp; 311 u_int i, j, len, env_len, escape_char, window, packetmax; 312 int new_fd[3]; 313 314 /* Reply for SSHMUX_COMMAND_OPEN */ 315 cctx = xcalloc(1, sizeof(*cctx)); 316 cctx->term = NULL; 317 cctx->rid = rid; 318 cmd = reserved = NULL; 319 cctx->env = NULL; 320 env_len = 0; 321 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL || 322 buffer_get_int_ret(&cctx->want_tty, m) != 0 || 323 buffer_get_int_ret(&cctx->want_x_fwd, m) != 0 || 324 buffer_get_int_ret(&cctx->want_agent_fwd, m) != 0 || 325 buffer_get_int_ret(&cctx->want_subsys, m) != 0 || 326 buffer_get_int_ret(&escape_char, m) != 0 || 327 (cctx->term = buffer_get_string_ret(m, &len)) == NULL || 328 (cmd = buffer_get_string_ret(m, &len)) == NULL) { 329 malf: 330 if (cmd != NULL) 331 xfree(cmd); 332 if (reserved != NULL) 333 xfree(reserved); 334 for (j = 0; j < env_len; j++) 335 xfree(cctx->env[j]); 336 if (env_len > 0) 337 xfree(cctx->env); 338 if (cctx->term != NULL) 339 xfree(cctx->term); 340 xfree(cctx); 341 error("%s: malformed message", __func__); 342 return -1; 343 } 344 xfree(reserved); 345 reserved = NULL; 346 347 while (buffer_len(m) > 0) { 348 #define MUX_MAX_ENV_VARS 4096 349 if ((cp = buffer_get_string_ret(m, &len)) == NULL) 350 goto malf; 351 if (!env_permitted(cp)) { 352 xfree(cp); 353 continue; 354 } 355 cctx->env = xrealloc(cctx->env, env_len + 2, 356 sizeof(*cctx->env)); 357 cctx->env[env_len++] = cp; 358 cctx->env[env_len] = NULL; 359 if (env_len > MUX_MAX_ENV_VARS) { 360 error(">%d environment variables received, ignoring " 361 "additional", MUX_MAX_ENV_VARS); 362 break; 363 } 364 } 365 366 debug2("%s: channel %d: request tty %d, X %d, agent %d, subsys %d, " 367 "term \"%s\", cmd \"%s\", env %u", __func__, c->self, 368 cctx->want_tty, cctx->want_x_fwd, cctx->want_agent_fwd, 369 cctx->want_subsys, cctx->term, cmd, env_len); 370 371 buffer_init(&cctx->cmd); 372 buffer_append(&cctx->cmd, cmd, strlen(cmd)); 373 xfree(cmd); 374 cmd = NULL; 375 376 /* Gather fds from client */ 377 for(i = 0; i < 3; i++) { 378 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) { 379 error("%s: failed to receive fd %d from slave", 380 __func__, i); 381 for (j = 0; j < i; j++) 382 close(new_fd[j]); 383 for (j = 0; j < env_len; j++) 384 xfree(cctx->env[j]); 385 if (env_len > 0) 386 xfree(cctx->env); 387 xfree(cctx->term); 388 buffer_free(&cctx->cmd); 389 xfree(cctx); 390 391 /* prepare reply */ 392 buffer_put_int(r, MUX_S_FAILURE); 393 buffer_put_int(r, rid); 394 buffer_put_cstring(r, 395 "did not receive file descriptors"); 396 return -1; 397 } 398 } 399 400 debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__, 401 new_fd[0], new_fd[1], new_fd[2]); 402 403 /* XXX support multiple child sessions in future */ 404 if (c->remote_id != -1) { 405 debug2("%s: session already open", __func__); 406 /* prepare reply */ 407 buffer_put_int(r, MUX_S_FAILURE); 408 buffer_put_int(r, rid); 409 buffer_put_cstring(r, "Multiple sessions not supported"); 410 cleanup: 411 close(new_fd[0]); 412 close(new_fd[1]); 413 close(new_fd[2]); 414 xfree(cctx->term); 415 if (env_len != 0) { 416 for (i = 0; i < env_len; i++) 417 xfree(cctx->env[i]); 418 xfree(cctx->env); 419 } 420 buffer_free(&cctx->cmd); 421 xfree(cctx); 422 return 0; 423 } 424 425 if (options.control_master == SSHCTL_MASTER_ASK || 426 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 427 if (!ask_permission("Allow shared connection to %s? ", host)) { 428 debug2("%s: session refused by user", __func__); 429 /* prepare reply */ 430 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 431 buffer_put_int(r, rid); 432 buffer_put_cstring(r, "Permission denied"); 433 goto cleanup; 434 } 435 } 436 437 /* Try to pick up ttymodes from client before it goes raw */ 438 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1) 439 error("%s: tcgetattr: %s", __func__, strerror(errno)); 440 441 /* enable nonblocking unless tty */ 442 if (!isatty(new_fd[0])) 443 set_nonblock(new_fd[0]); 444 if (!isatty(new_fd[1])) 445 set_nonblock(new_fd[1]); 446 if (!isatty(new_fd[2])) 447 set_nonblock(new_fd[2]); 448 449 window = CHAN_SES_WINDOW_DEFAULT; 450 packetmax = CHAN_SES_PACKET_DEFAULT; 451 if (cctx->want_tty) { 452 window >>= 1; 453 packetmax >>= 1; 454 } 455 456 nc = channel_new("session", SSH_CHANNEL_OPENING, 457 new_fd[0], new_fd[1], new_fd[2], window, packetmax, 458 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); 459 460 nc->ctl_chan = c->self; /* link session -> control channel */ 461 c->remote_id = nc->self; /* link control -> session channel */ 462 463 if (cctx->want_tty && escape_char != 0xffffffff) { 464 channel_register_filter(nc->self, 465 client_simple_escape_filter, NULL, 466 client_filter_cleanup, 467 client_new_escape_filter_ctx((int)escape_char)); 468 } 469 470 debug2("%s: channel_new: %d linked to control channel %d", 471 __func__, nc->self, nc->ctl_chan); 472 473 channel_send_open(nc->self); 474 channel_register_open_confirm(nc->self, mux_session_confirm, cctx); 475 c->mux_pause = 1; /* stop handling messages until open_confirm done */ 476 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1); 477 478 /* reply is deferred, sent by mux_session_confirm */ 479 return 0; 480 } 481 482 static int 483 process_mux_alive_check(u_int rid, Channel *c, Buffer *m, Buffer *r) 484 { 485 debug2("%s: channel %d: alive check", __func__, c->self); 486 487 /* prepare reply */ 488 buffer_put_int(r, MUX_S_ALIVE); 489 buffer_put_int(r, rid); 490 buffer_put_int(r, (u_int)getpid()); 491 492 return 0; 493 } 494 495 static int 496 process_mux_terminate(u_int rid, Channel *c, Buffer *m, Buffer *r) 497 { 498 debug2("%s: channel %d: terminate request", __func__, c->self); 499 500 if (options.control_master == SSHCTL_MASTER_ASK || 501 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 502 if (!ask_permission("Terminate shared connection to %s? ", 503 host)) { 504 debug2("%s: termination refused by user", __func__); 505 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 506 buffer_put_int(r, rid); 507 buffer_put_cstring(r, "Permission denied"); 508 return 0; 509 } 510 } 511 512 quit_pending = 1; 513 buffer_put_int(r, MUX_S_OK); 514 buffer_put_int(r, rid); 515 /* XXX exit happens too soon - message never makes it to client */ 516 return 0; 517 } 518 519 static char * 520 format_forward(u_int ftype, Forward *fwd) 521 { 522 char *ret; 523 524 switch (ftype) { 525 case MUX_FWD_LOCAL: 526 xasprintf(&ret, "local forward %.200s:%d -> %.200s:%d", 527 (fwd->listen_host == NULL) ? 528 (options.gateway_ports ? "*" : "LOCALHOST") : 529 fwd->listen_host, fwd->listen_port, 530 fwd->connect_host, fwd->connect_port); 531 break; 532 case MUX_FWD_DYNAMIC: 533 xasprintf(&ret, "dynamic forward %.200s:%d -> *", 534 (fwd->listen_host == NULL) ? 535 (options.gateway_ports ? "*" : "LOCALHOST") : 536 fwd->listen_host, fwd->listen_port); 537 break; 538 case MUX_FWD_REMOTE: 539 xasprintf(&ret, "remote forward %.200s:%d -> %.200s:%d", 540 (fwd->listen_host == NULL) ? 541 "LOCALHOST" : fwd->listen_host, 542 fwd->listen_port, 543 fwd->connect_host, fwd->connect_port); 544 break; 545 default: 546 fatal("%s: unknown forward type %u", __func__, ftype); 547 } 548 return ret; 549 } 550 551 static int 552 compare_host(const char *a, const char *b) 553 { 554 if (a == NULL && b == NULL) 555 return 1; 556 if (a == NULL || b == NULL) 557 return 0; 558 return strcmp(a, b) == 0; 559 } 560 561 static int 562 compare_forward(Forward *a, Forward *b) 563 { 564 if (!compare_host(a->listen_host, b->listen_host)) 565 return 0; 566 if (a->listen_port != b->listen_port) 567 return 0; 568 if (!compare_host(a->connect_host, b->connect_host)) 569 return 0; 570 if (a->connect_port != b->connect_port) 571 return 0; 572 573 return 1; 574 } 575 576 static void 577 mux_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 578 { 579 struct mux_channel_confirm_ctx *fctx = ctxt; 580 char *failmsg = NULL; 581 Forward *rfwd; 582 Channel *c; 583 Buffer out; 584 585 if ((c = channel_by_id(fctx->cid)) == NULL) { 586 /* no channel for reply */ 587 error("%s: unknown channel", __func__); 588 return; 589 } 590 buffer_init(&out); 591 if (fctx->fid >= options.num_remote_forwards) { 592 xasprintf(&failmsg, "unknown forwarding id %d", fctx->fid); 593 goto fail; 594 } 595 rfwd = &options.remote_forwards[fctx->fid]; 596 debug("%s: %s for: listen %d, connect %s:%d", __func__, 597 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 598 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 599 if (type == SSH2_MSG_REQUEST_SUCCESS) { 600 if (rfwd->listen_port == 0) { 601 rfwd->allocated_port = packet_get_int(); 602 logit("Allocated port %u for mux remote forward" 603 " to %s:%d", rfwd->allocated_port, 604 rfwd->connect_host, rfwd->connect_port); 605 buffer_put_int(&out, MUX_S_REMOTE_PORT); 606 buffer_put_int(&out, fctx->rid); 607 buffer_put_int(&out, rfwd->allocated_port); 608 channel_update_permitted_opens(rfwd->handle, 609 rfwd->allocated_port); 610 } else { 611 buffer_put_int(&out, MUX_S_OK); 612 buffer_put_int(&out, fctx->rid); 613 } 614 goto out; 615 } else { 616 if (rfwd->listen_port == 0) 617 channel_update_permitted_opens(rfwd->handle, -1); 618 xasprintf(&failmsg, "remote port forwarding failed for " 619 "listen port %d", rfwd->listen_port); 620 } 621 fail: 622 error("%s: %s", __func__, failmsg); 623 buffer_put_int(&out, MUX_S_FAILURE); 624 buffer_put_int(&out, fctx->rid); 625 buffer_put_cstring(&out, failmsg); 626 xfree(failmsg); 627 out: 628 buffer_put_string(&c->output, buffer_ptr(&out), buffer_len(&out)); 629 buffer_free(&out); 630 if (c->mux_pause <= 0) 631 fatal("%s: mux_pause %d", __func__, c->mux_pause); 632 c->mux_pause = 0; /* start processing messages again */ 633 } 634 635 static int 636 process_mux_open_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r) 637 { 638 Forward fwd; 639 char *fwd_desc = NULL; 640 u_int ftype; 641 int i, ret = 0, freefwd = 1; 642 643 fwd.listen_host = fwd.connect_host = NULL; 644 if (buffer_get_int_ret(&ftype, m) != 0 || 645 (fwd.listen_host = buffer_get_string_ret(m, NULL)) == NULL || 646 buffer_get_int_ret(&fwd.listen_port, m) != 0 || 647 (fwd.connect_host = buffer_get_string_ret(m, NULL)) == NULL || 648 buffer_get_int_ret(&fwd.connect_port, m) != 0) { 649 error("%s: malformed message", __func__); 650 ret = -1; 651 goto out; 652 } 653 654 if (*fwd.listen_host == '\0') { 655 xfree(fwd.listen_host); 656 fwd.listen_host = NULL; 657 } 658 if (*fwd.connect_host == '\0') { 659 xfree(fwd.connect_host); 660 fwd.connect_host = NULL; 661 } 662 663 debug2("%s: channel %d: request %s", __func__, c->self, 664 (fwd_desc = format_forward(ftype, &fwd))); 665 666 if (ftype != MUX_FWD_LOCAL && ftype != MUX_FWD_REMOTE && 667 ftype != MUX_FWD_DYNAMIC) { 668 logit("%s: invalid forwarding type %u", __func__, ftype); 669 invalid: 670 if (fwd.listen_host) 671 xfree(fwd.listen_host); 672 if (fwd.connect_host) 673 xfree(fwd.connect_host); 674 buffer_put_int(r, MUX_S_FAILURE); 675 buffer_put_int(r, rid); 676 buffer_put_cstring(r, "Invalid forwarding request"); 677 return 0; 678 } 679 if (fwd.listen_port >= 65536) { 680 logit("%s: invalid listen port %u", __func__, 681 fwd.listen_port); 682 goto invalid; 683 } 684 if (fwd.connect_port >= 65536 || (ftype != MUX_FWD_DYNAMIC && 685 ftype != MUX_FWD_REMOTE && fwd.connect_port == 0)) { 686 logit("%s: invalid connect port %u", __func__, 687 fwd.connect_port); 688 goto invalid; 689 } 690 if (ftype != MUX_FWD_DYNAMIC && fwd.connect_host == NULL) { 691 logit("%s: missing connect host", __func__); 692 goto invalid; 693 } 694 695 /* Skip forwards that have already been requested */ 696 switch (ftype) { 697 case MUX_FWD_LOCAL: 698 case MUX_FWD_DYNAMIC: 699 for (i = 0; i < options.num_local_forwards; i++) { 700 if (compare_forward(&fwd, 701 options.local_forwards + i)) { 702 exists: 703 debug2("%s: found existing forwarding", 704 __func__); 705 buffer_put_int(r, MUX_S_OK); 706 buffer_put_int(r, rid); 707 goto out; 708 } 709 } 710 break; 711 case MUX_FWD_REMOTE: 712 for (i = 0; i < options.num_remote_forwards; i++) { 713 if (compare_forward(&fwd, 714 options.remote_forwards + i)) { 715 if (fwd.listen_port != 0) 716 goto exists; 717 debug2("%s: found allocated port", 718 __func__); 719 buffer_put_int(r, MUX_S_REMOTE_PORT); 720 buffer_put_int(r, rid); 721 buffer_put_int(r, 722 options.remote_forwards[i].allocated_port); 723 goto out; 724 } 725 } 726 break; 727 } 728 729 if (options.control_master == SSHCTL_MASTER_ASK || 730 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 731 if (!ask_permission("Open %s on %s?", fwd_desc, host)) { 732 debug2("%s: forwarding refused by user", __func__); 733 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 734 buffer_put_int(r, rid); 735 buffer_put_cstring(r, "Permission denied"); 736 goto out; 737 } 738 } 739 740 if (ftype == MUX_FWD_LOCAL || ftype == MUX_FWD_DYNAMIC) { 741 if (channel_setup_local_fwd_listener(fwd.listen_host, 742 fwd.listen_port, fwd.connect_host, fwd.connect_port, 743 options.gateway_ports) < 0) { 744 fail: 745 logit("slave-requested %s failed", fwd_desc); 746 buffer_put_int(r, MUX_S_FAILURE); 747 buffer_put_int(r, rid); 748 buffer_put_cstring(r, "Port forwarding failed"); 749 goto out; 750 } 751 add_local_forward(&options, &fwd); 752 freefwd = 0; 753 } else { 754 struct mux_channel_confirm_ctx *fctx; 755 756 fwd.handle = channel_request_remote_forwarding(fwd.listen_host, 757 fwd.listen_port, fwd.connect_host, fwd.connect_port); 758 if (fwd.handle < 0) 759 goto fail; 760 add_remote_forward(&options, &fwd); 761 fctx = xcalloc(1, sizeof(*fctx)); 762 fctx->cid = c->self; 763 fctx->rid = rid; 764 fctx->fid = options.num_remote_forwards - 1; 765 client_register_global_confirm(mux_confirm_remote_forward, 766 fctx); 767 freefwd = 0; 768 c->mux_pause = 1; /* wait for mux_confirm_remote_forward */ 769 /* delayed reply in mux_confirm_remote_forward */ 770 goto out; 771 } 772 buffer_put_int(r, MUX_S_OK); 773 buffer_put_int(r, rid); 774 out: 775 if (fwd_desc != NULL) 776 xfree(fwd_desc); 777 if (freefwd) { 778 if (fwd.listen_host != NULL) 779 xfree(fwd.listen_host); 780 if (fwd.connect_host != NULL) 781 xfree(fwd.connect_host); 782 } 783 return ret; 784 } 785 786 static int 787 process_mux_close_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r) 788 { 789 Forward fwd, *found_fwd; 790 char *fwd_desc = NULL; 791 const char *error_reason = NULL; 792 u_int ftype; 793 int i, listen_port, ret = 0; 794 795 fwd.listen_host = fwd.connect_host = NULL; 796 if (buffer_get_int_ret(&ftype, m) != 0 || 797 (fwd.listen_host = buffer_get_string_ret(m, NULL)) == NULL || 798 buffer_get_int_ret(&fwd.listen_port, m) != 0 || 799 (fwd.connect_host = buffer_get_string_ret(m, NULL)) == NULL || 800 buffer_get_int_ret(&fwd.connect_port, m) != 0) { 801 error("%s: malformed message", __func__); 802 ret = -1; 803 goto out; 804 } 805 806 if (*fwd.listen_host == '\0') { 807 xfree(fwd.listen_host); 808 fwd.listen_host = NULL; 809 } 810 if (*fwd.connect_host == '\0') { 811 xfree(fwd.connect_host); 812 fwd.connect_host = NULL; 813 } 814 815 debug2("%s: channel %d: request cancel %s", __func__, c->self, 816 (fwd_desc = format_forward(ftype, &fwd))); 817 818 /* make sure this has been requested */ 819 found_fwd = NULL; 820 switch (ftype) { 821 case MUX_FWD_LOCAL: 822 case MUX_FWD_DYNAMIC: 823 for (i = 0; i < options.num_local_forwards; i++) { 824 if (compare_forward(&fwd, 825 options.local_forwards + i)) { 826 found_fwd = options.local_forwards + i; 827 break; 828 } 829 } 830 break; 831 case MUX_FWD_REMOTE: 832 for (i = 0; i < options.num_remote_forwards; i++) { 833 if (compare_forward(&fwd, 834 options.remote_forwards + i)) { 835 found_fwd = options.remote_forwards + i; 836 break; 837 } 838 } 839 break; 840 } 841 842 if (found_fwd == NULL) 843 error_reason = "port not forwarded"; 844 else if (ftype == MUX_FWD_REMOTE) { 845 /* 846 * This shouldn't fail unless we confused the host/port 847 * between options.remote_forwards and permitted_opens. 848 * However, for dynamic allocated listen ports we need 849 * to lookup the actual listen port. 850 */ 851 listen_port = (fwd.listen_port == 0) ? 852 found_fwd->allocated_port : fwd.listen_port; 853 if (channel_request_rforward_cancel(fwd.listen_host, 854 listen_port) == -1) 855 error_reason = "port not in permitted opens"; 856 } else { /* local and dynamic forwards */ 857 /* Ditto */ 858 if (channel_cancel_lport_listener(fwd.listen_host, 859 fwd.listen_port, fwd.connect_port, 860 options.gateway_ports) == -1) 861 error_reason = "port not found"; 862 } 863 864 if (error_reason == NULL) { 865 buffer_put_int(r, MUX_S_OK); 866 buffer_put_int(r, rid); 867 868 if (found_fwd->listen_host != NULL) 869 xfree(found_fwd->listen_host); 870 if (found_fwd->connect_host != NULL) 871 xfree(found_fwd->connect_host); 872 found_fwd->listen_host = found_fwd->connect_host = NULL; 873 found_fwd->listen_port = found_fwd->connect_port = 0; 874 } else { 875 buffer_put_int(r, MUX_S_FAILURE); 876 buffer_put_int(r, rid); 877 buffer_put_cstring(r, error_reason); 878 } 879 out: 880 if (fwd_desc != NULL) 881 xfree(fwd_desc); 882 if (fwd.listen_host != NULL) 883 xfree(fwd.listen_host); 884 if (fwd.connect_host != NULL) 885 xfree(fwd.connect_host); 886 887 return ret; 888 } 889 890 static int 891 process_mux_stdio_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r) 892 { 893 Channel *nc; 894 char *reserved, *chost; 895 u_int cport, i, j; 896 int new_fd[2]; 897 898 chost = reserved = NULL; 899 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL || 900 (chost = buffer_get_string_ret(m, NULL)) == NULL || 901 buffer_get_int_ret(&cport, m) != 0) { 902 if (reserved != NULL) 903 xfree(reserved); 904 if (chost != NULL) 905 xfree(chost); 906 error("%s: malformed message", __func__); 907 return -1; 908 } 909 xfree(reserved); 910 911 debug2("%s: channel %d: request stdio fwd to %s:%u", 912 __func__, c->self, chost, cport); 913 914 /* Gather fds from client */ 915 for(i = 0; i < 2; i++) { 916 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) { 917 error("%s: failed to receive fd %d from slave", 918 __func__, i); 919 for (j = 0; j < i; j++) 920 close(new_fd[j]); 921 xfree(chost); 922 923 /* prepare reply */ 924 buffer_put_int(r, MUX_S_FAILURE); 925 buffer_put_int(r, rid); 926 buffer_put_cstring(r, 927 "did not receive file descriptors"); 928 return -1; 929 } 930 } 931 932 debug3("%s: got fds stdin %d, stdout %d", __func__, 933 new_fd[0], new_fd[1]); 934 935 /* XXX support multiple child sessions in future */ 936 if (c->remote_id != -1) { 937 debug2("%s: session already open", __func__); 938 /* prepare reply */ 939 buffer_put_int(r, MUX_S_FAILURE); 940 buffer_put_int(r, rid); 941 buffer_put_cstring(r, "Multiple sessions not supported"); 942 cleanup: 943 close(new_fd[0]); 944 close(new_fd[1]); 945 xfree(chost); 946 return 0; 947 } 948 949 if (options.control_master == SSHCTL_MASTER_ASK || 950 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 951 if (!ask_permission("Allow forward to %s:%u? ", 952 chost, cport)) { 953 debug2("%s: stdio fwd refused by user", __func__); 954 /* prepare reply */ 955 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 956 buffer_put_int(r, rid); 957 buffer_put_cstring(r, "Permission denied"); 958 goto cleanup; 959 } 960 } 961 962 /* enable nonblocking unless tty */ 963 if (!isatty(new_fd[0])) 964 set_nonblock(new_fd[0]); 965 if (!isatty(new_fd[1])) 966 set_nonblock(new_fd[1]); 967 968 nc = channel_connect_stdio_fwd(chost, cport, new_fd[0], new_fd[1]); 969 970 nc->ctl_chan = c->self; /* link session -> control channel */ 971 c->remote_id = nc->self; /* link control -> session channel */ 972 973 debug2("%s: channel_new: %d linked to control channel %d", 974 __func__, nc->self, nc->ctl_chan); 975 976 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1); 977 978 /* prepare reply */ 979 /* XXX defer until channel confirmed */ 980 buffer_put_int(r, MUX_S_SESSION_OPENED); 981 buffer_put_int(r, rid); 982 buffer_put_int(r, nc->self); 983 984 return 0; 985 } 986 987 static int 988 process_mux_stop_listening(u_int rid, Channel *c, Buffer *m, Buffer *r) 989 { 990 debug("%s: channel %d: stop listening", __func__, c->self); 991 992 if (options.control_master == SSHCTL_MASTER_ASK || 993 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 994 if (!ask_permission("Disable further multiplexing on shared " 995 "connection to %s? ", host)) { 996 debug2("%s: stop listen refused by user", __func__); 997 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 998 buffer_put_int(r, rid); 999 buffer_put_cstring(r, "Permission denied"); 1000 return 0; 1001 } 1002 } 1003 1004 if (mux_listener_channel != NULL) { 1005 channel_free(mux_listener_channel); 1006 client_stop_mux(); 1007 xfree(options.control_path); 1008 options.control_path = NULL; 1009 mux_listener_channel = NULL; 1010 muxserver_sock = -1; 1011 } 1012 1013 /* prepare reply */ 1014 buffer_put_int(r, MUX_S_OK); 1015 buffer_put_int(r, rid); 1016 1017 return 0; 1018 } 1019 1020 /* Channel callbacks fired on read/write from mux slave fd */ 1021 static int 1022 mux_master_read_cb(Channel *c) 1023 { 1024 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx; 1025 Buffer in, out; 1026 void *ptr; 1027 u_int type, rid, have, i; 1028 int ret = -1; 1029 1030 /* Setup ctx and */ 1031 if (c->mux_ctx == NULL) { 1032 state = xcalloc(1, sizeof(*state)); 1033 c->mux_ctx = state; 1034 channel_register_cleanup(c->self, 1035 mux_master_control_cleanup_cb, 0); 1036 1037 /* Send hello */ 1038 buffer_init(&out); 1039 buffer_put_int(&out, MUX_MSG_HELLO); 1040 buffer_put_int(&out, SSHMUX_VER); 1041 /* no extensions */ 1042 buffer_put_string(&c->output, buffer_ptr(&out), 1043 buffer_len(&out)); 1044 buffer_free(&out); 1045 debug3("%s: channel %d: hello sent", __func__, c->self); 1046 return 0; 1047 } 1048 1049 buffer_init(&in); 1050 buffer_init(&out); 1051 1052 /* Channel code ensures that we receive whole packets */ 1053 if ((ptr = buffer_get_string_ptr_ret(&c->input, &have)) == NULL) { 1054 malf: 1055 error("%s: malformed message", __func__); 1056 goto out; 1057 } 1058 buffer_append(&in, ptr, have); 1059 1060 if (buffer_get_int_ret(&type, &in) != 0) 1061 goto malf; 1062 debug3("%s: channel %d packet type 0x%08x len %u", 1063 __func__, c->self, type, buffer_len(&in)); 1064 1065 if (type == MUX_MSG_HELLO) 1066 rid = 0; 1067 else { 1068 if (!state->hello_rcvd) { 1069 error("%s: expected MUX_MSG_HELLO(0x%08x), " 1070 "received 0x%08x", __func__, MUX_MSG_HELLO, type); 1071 goto out; 1072 } 1073 if (buffer_get_int_ret(&rid, &in) != 0) 1074 goto malf; 1075 } 1076 1077 for (i = 0; mux_master_handlers[i].handler != NULL; i++) { 1078 if (type == mux_master_handlers[i].type) { 1079 ret = mux_master_handlers[i].handler(rid, c, &in, &out); 1080 break; 1081 } 1082 } 1083 if (mux_master_handlers[i].handler == NULL) { 1084 error("%s: unsupported mux message 0x%08x", __func__, type); 1085 buffer_put_int(&out, MUX_S_FAILURE); 1086 buffer_put_int(&out, rid); 1087 buffer_put_cstring(&out, "unsupported request"); 1088 ret = 0; 1089 } 1090 /* Enqueue reply packet */ 1091 if (buffer_len(&out) != 0) { 1092 buffer_put_string(&c->output, buffer_ptr(&out), 1093 buffer_len(&out)); 1094 } 1095 out: 1096 buffer_free(&in); 1097 buffer_free(&out); 1098 return ret; 1099 } 1100 1101 void 1102 mux_exit_message(Channel *c, int exitval) 1103 { 1104 Buffer m; 1105 Channel *mux_chan; 1106 1107 debug3("%s: channel %d: exit message, evitval %d", __func__, c->self, 1108 exitval); 1109 1110 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL) 1111 fatal("%s: channel %d missing mux channel %d", 1112 __func__, c->self, c->ctl_chan); 1113 1114 /* Append exit message packet to control socket output queue */ 1115 buffer_init(&m); 1116 buffer_put_int(&m, MUX_S_EXIT_MESSAGE); 1117 buffer_put_int(&m, c->self); 1118 buffer_put_int(&m, exitval); 1119 1120 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m)); 1121 buffer_free(&m); 1122 } 1123 1124 void 1125 mux_tty_alloc_failed(Channel *c) 1126 { 1127 Buffer m; 1128 Channel *mux_chan; 1129 1130 debug3("%s: channel %d: TTY alloc failed", __func__, c->self); 1131 1132 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL) 1133 fatal("%s: channel %d missing mux channel %d", 1134 __func__, c->self, c->ctl_chan); 1135 1136 /* Append exit message packet to control socket output queue */ 1137 buffer_init(&m); 1138 buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL); 1139 buffer_put_int(&m, c->self); 1140 1141 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m)); 1142 buffer_free(&m); 1143 } 1144 1145 /* Prepare a mux master to listen on a Unix domain socket. */ 1146 void 1147 muxserver_listen(void) 1148 { 1149 struct sockaddr_un addr; 1150 socklen_t sun_len; 1151 mode_t old_umask; 1152 char *orig_control_path = options.control_path; 1153 char rbuf[16+1]; 1154 u_int i, r; 1155 1156 if (options.control_path == NULL || 1157 options.control_master == SSHCTL_MASTER_NO) 1158 return; 1159 1160 debug("setting up multiplex master socket"); 1161 1162 /* 1163 * Use a temporary path before listen so we can pseudo-atomically 1164 * establish the listening socket in its final location to avoid 1165 * other processes racing in between bind() and listen() and hitting 1166 * an unready socket. 1167 */ 1168 for (i = 0; i < sizeof(rbuf) - 1; i++) { 1169 r = arc4random_uniform(26+26+10); 1170 rbuf[i] = (r < 26) ? 'a' + r : 1171 (r < 26*2) ? 'A' + r - 26 : 1172 '0' + r - 26 - 26; 1173 } 1174 rbuf[sizeof(rbuf) - 1] = '\0'; 1175 options.control_path = NULL; 1176 xasprintf(&options.control_path, "%s.%s", orig_control_path, rbuf); 1177 debug3("%s: temporary control path %s", __func__, options.control_path); 1178 1179 memset(&addr, '\0', sizeof(addr)); 1180 addr.sun_family = AF_UNIX; 1181 sun_len = offsetof(struct sockaddr_un, sun_path) + 1182 strlen(options.control_path) + 1; 1183 1184 if (strlcpy(addr.sun_path, options.control_path, 1185 sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) { 1186 error("ControlPath \"%s\" too long for Unix domain socket", 1187 options.control_path); 1188 goto disable_mux_master; 1189 } 1190 1191 if ((muxserver_sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) 1192 fatal("%s socket(): %s", __func__, strerror(errno)); 1193 1194 old_umask = umask(0177); 1195 if (bind(muxserver_sock, (struct sockaddr *)&addr, sun_len) == -1) { 1196 if (errno == EINVAL || errno == EADDRINUSE) { 1197 error("ControlSocket %s already exists, " 1198 "disabling multiplexing", options.control_path); 1199 disable_mux_master: 1200 if (muxserver_sock != -1) { 1201 close(muxserver_sock); 1202 muxserver_sock = -1; 1203 } 1204 xfree(orig_control_path); 1205 xfree(options.control_path); 1206 options.control_path = NULL; 1207 options.control_master = SSHCTL_MASTER_NO; 1208 return; 1209 } else 1210 fatal("%s bind(): %s", __func__, strerror(errno)); 1211 } 1212 umask(old_umask); 1213 1214 if (listen(muxserver_sock, 64) == -1) 1215 fatal("%s listen(): %s", __func__, strerror(errno)); 1216 1217 /* Now atomically "move" the mux socket into position */ 1218 if (link(options.control_path, orig_control_path) != 0) { 1219 if (errno != EEXIST) { 1220 fatal("%s: link mux listener %s => %s: %s", __func__, 1221 options.control_path, orig_control_path, 1222 strerror(errno)); 1223 } 1224 error("ControlSocket %s already exists, disabling multiplexing", 1225 orig_control_path); 1226 unlink(options.control_path); 1227 goto disable_mux_master; 1228 } 1229 unlink(options.control_path); 1230 xfree(options.control_path); 1231 options.control_path = orig_control_path; 1232 1233 set_nonblock(muxserver_sock); 1234 1235 mux_listener_channel = channel_new("mux listener", 1236 SSH_CHANNEL_MUX_LISTENER, muxserver_sock, muxserver_sock, -1, 1237 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1238 0, options.control_path, 1); 1239 mux_listener_channel->mux_rcb = mux_master_read_cb; 1240 debug3("%s: mux listener channel %d fd %d", __func__, 1241 mux_listener_channel->self, mux_listener_channel->sock); 1242 } 1243 1244 /* Callback on open confirmation in mux master for a mux client session. */ 1245 static void 1246 mux_session_confirm(int id, int success, void *arg) 1247 { 1248 struct mux_session_confirm_ctx *cctx = arg; 1249 const char *display; 1250 Channel *c, *cc; 1251 int i; 1252 Buffer reply; 1253 1254 if (cctx == NULL) 1255 fatal("%s: cctx == NULL", __func__); 1256 if ((c = channel_by_id(id)) == NULL) 1257 fatal("%s: no channel for id %d", __func__, id); 1258 if ((cc = channel_by_id(c->ctl_chan)) == NULL) 1259 fatal("%s: channel %d lacks control channel %d", __func__, 1260 id, c->ctl_chan); 1261 1262 if (!success) { 1263 debug3("%s: sending failure reply", __func__); 1264 /* prepare reply */ 1265 buffer_init(&reply); 1266 buffer_put_int(&reply, MUX_S_FAILURE); 1267 buffer_put_int(&reply, cctx->rid); 1268 buffer_put_cstring(&reply, "Session open refused by peer"); 1269 goto done; 1270 } 1271 1272 display = getenv("DISPLAY"); 1273 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) { 1274 char *proto, *data; 1275 1276 /* Get reasonable local authentication information. */ 1277 client_x11_get_proto(display, options.xauth_location, 1278 options.forward_x11_trusted, options.forward_x11_timeout, 1279 &proto, &data); 1280 /* Request forwarding with authentication spoofing. */ 1281 debug("Requesting X11 forwarding with authentication " 1282 "spoofing."); 1283 x11_request_forwarding_with_spoofing(id, display, proto, 1284 data, 1); 1285 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); 1286 /* XXX exit_on_forward_failure */ 1287 } 1288 1289 if (cctx->want_agent_fwd && options.forward_agent) { 1290 debug("Requesting authentication agent forwarding."); 1291 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1292 packet_send(); 1293 } 1294 1295 client_session2_setup(id, cctx->want_tty, cctx->want_subsys, 1296 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env); 1297 1298 debug3("%s: sending success reply", __func__); 1299 /* prepare reply */ 1300 buffer_init(&reply); 1301 buffer_put_int(&reply, MUX_S_SESSION_OPENED); 1302 buffer_put_int(&reply, cctx->rid); 1303 buffer_put_int(&reply, c->self); 1304 1305 done: 1306 /* Send reply */ 1307 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply)); 1308 buffer_free(&reply); 1309 1310 if (cc->mux_pause <= 0) 1311 fatal("%s: mux_pause %d", __func__, cc->mux_pause); 1312 cc->mux_pause = 0; /* start processing messages again */ 1313 c->open_confirm_ctx = NULL; 1314 buffer_free(&cctx->cmd); 1315 xfree(cctx->term); 1316 if (cctx->env != NULL) { 1317 for (i = 0; cctx->env[i] != NULL; i++) 1318 xfree(cctx->env[i]); 1319 xfree(cctx->env); 1320 } 1321 xfree(cctx); 1322 } 1323 1324 /* ** Multiplexing client support */ 1325 1326 /* Exit signal handler */ 1327 static void 1328 control_client_sighandler(int signo) 1329 { 1330 muxclient_terminate = signo; 1331 } 1332 1333 /* 1334 * Relay signal handler - used to pass some signals from mux client to 1335 * mux master. 1336 */ 1337 static void 1338 control_client_sigrelay(int signo) 1339 { 1340 int save_errno = errno; 1341 1342 if (muxserver_pid > 1) 1343 kill(muxserver_pid, signo); 1344 1345 errno = save_errno; 1346 } 1347 1348 static int 1349 mux_client_read(int fd, Buffer *b, u_int need) 1350 { 1351 u_int have; 1352 ssize_t len; 1353 u_char *p; 1354 struct pollfd pfd; 1355 1356 pfd.fd = fd; 1357 pfd.events = POLLIN; 1358 p = buffer_append_space(b, need); 1359 for (have = 0; have < need; ) { 1360 if (muxclient_terminate) { 1361 errno = EINTR; 1362 return -1; 1363 } 1364 len = read(fd, p + have, need - have); 1365 if (len < 0) { 1366 switch (errno) { 1367 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN) 1368 case EWOULDBLOCK: 1369 #endif 1370 case EAGAIN: 1371 (void)poll(&pfd, 1, -1); 1372 /* FALLTHROUGH */ 1373 case EINTR: 1374 continue; 1375 default: 1376 return -1; 1377 } 1378 } 1379 if (len == 0) { 1380 errno = EPIPE; 1381 return -1; 1382 } 1383 have += (u_int)len; 1384 } 1385 return 0; 1386 } 1387 1388 static int 1389 mux_client_write_packet(int fd, Buffer *m) 1390 { 1391 Buffer queue; 1392 u_int have, need; 1393 int oerrno, len; 1394 u_char *ptr; 1395 struct pollfd pfd; 1396 1397 pfd.fd = fd; 1398 pfd.events = POLLOUT; 1399 buffer_init(&queue); 1400 buffer_put_string(&queue, buffer_ptr(m), buffer_len(m)); 1401 1402 need = buffer_len(&queue); 1403 ptr = buffer_ptr(&queue); 1404 1405 for (have = 0; have < need; ) { 1406 if (muxclient_terminate) { 1407 buffer_free(&queue); 1408 errno = EINTR; 1409 return -1; 1410 } 1411 len = write(fd, ptr + have, need - have); 1412 if (len < 0) { 1413 switch (errno) { 1414 #if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN) 1415 case EWOULDBLOCK: 1416 #endif 1417 case EAGAIN: 1418 (void)poll(&pfd, 1, -1); 1419 /* FALLTHROUGH */ 1420 case EINTR: 1421 continue; 1422 default: 1423 oerrno = errno; 1424 buffer_free(&queue); 1425 errno = oerrno; 1426 return -1; 1427 } 1428 } 1429 if (len == 0) { 1430 buffer_free(&queue); 1431 errno = EPIPE; 1432 return -1; 1433 } 1434 have += (u_int)len; 1435 } 1436 buffer_free(&queue); 1437 return 0; 1438 } 1439 1440 static int 1441 mux_client_read_packet(int fd, Buffer *m) 1442 { 1443 Buffer queue; 1444 u_int need, have; 1445 void *ptr; 1446 int oerrno; 1447 1448 buffer_init(&queue); 1449 if (mux_client_read(fd, &queue, 4) != 0) { 1450 if ((oerrno = errno) == EPIPE) 1451 debug3("%s: read header failed: %s", __func__, strerror(errno)); 1452 errno = oerrno; 1453 return -1; 1454 } 1455 need = get_u32(buffer_ptr(&queue)); 1456 if (mux_client_read(fd, &queue, need) != 0) { 1457 oerrno = errno; 1458 debug3("%s: read body failed: %s", __func__, strerror(errno)); 1459 errno = oerrno; 1460 return -1; 1461 } 1462 ptr = buffer_get_string_ptr(&queue, &have); 1463 buffer_append(m, ptr, have); 1464 buffer_free(&queue); 1465 return 0; 1466 } 1467 1468 static int 1469 mux_client_hello_exchange(int fd) 1470 { 1471 Buffer m; 1472 u_int type, ver; 1473 1474 buffer_init(&m); 1475 buffer_put_int(&m, MUX_MSG_HELLO); 1476 buffer_put_int(&m, SSHMUX_VER); 1477 /* no extensions */ 1478 1479 if (mux_client_write_packet(fd, &m) != 0) 1480 fatal("%s: write packet: %s", __func__, strerror(errno)); 1481 1482 buffer_clear(&m); 1483 1484 /* Read their HELLO */ 1485 if (mux_client_read_packet(fd, &m) != 0) { 1486 buffer_free(&m); 1487 return -1; 1488 } 1489 1490 type = buffer_get_int(&m); 1491 if (type != MUX_MSG_HELLO) 1492 fatal("%s: expected HELLO (%u) received %u", 1493 __func__, MUX_MSG_HELLO, type); 1494 ver = buffer_get_int(&m); 1495 if (ver != SSHMUX_VER) 1496 fatal("Unsupported multiplexing protocol version %d " 1497 "(expected %d)", ver, SSHMUX_VER); 1498 debug2("%s: master version %u", __func__, ver); 1499 /* No extensions are presently defined */ 1500 while (buffer_len(&m) > 0) { 1501 char *name = buffer_get_string(&m, NULL); 1502 char *value = buffer_get_string(&m, NULL); 1503 1504 debug2("Unrecognised master extension \"%s\"", name); 1505 xfree(name); 1506 xfree(value); 1507 } 1508 buffer_free(&m); 1509 return 0; 1510 } 1511 1512 static u_int 1513 mux_client_request_alive(int fd) 1514 { 1515 Buffer m; 1516 char *e; 1517 u_int pid, type, rid; 1518 1519 debug3("%s: entering", __func__); 1520 1521 buffer_init(&m); 1522 buffer_put_int(&m, MUX_C_ALIVE_CHECK); 1523 buffer_put_int(&m, muxclient_request_id); 1524 1525 if (mux_client_write_packet(fd, &m) != 0) 1526 fatal("%s: write packet: %s", __func__, strerror(errno)); 1527 1528 buffer_clear(&m); 1529 1530 /* Read their reply */ 1531 if (mux_client_read_packet(fd, &m) != 0) { 1532 buffer_free(&m); 1533 return 0; 1534 } 1535 1536 type = buffer_get_int(&m); 1537 if (type != MUX_S_ALIVE) { 1538 e = buffer_get_string(&m, NULL); 1539 fatal("%s: master returned error: %s", __func__, e); 1540 } 1541 1542 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1543 fatal("%s: out of sequence reply: my id %u theirs %u", 1544 __func__, muxclient_request_id, rid); 1545 pid = buffer_get_int(&m); 1546 buffer_free(&m); 1547 1548 debug3("%s: done pid = %u", __func__, pid); 1549 1550 muxclient_request_id++; 1551 1552 return pid; 1553 } 1554 1555 static void 1556 mux_client_request_terminate(int fd) 1557 { 1558 Buffer m; 1559 char *e; 1560 u_int type, rid; 1561 1562 debug3("%s: entering", __func__); 1563 1564 buffer_init(&m); 1565 buffer_put_int(&m, MUX_C_TERMINATE); 1566 buffer_put_int(&m, muxclient_request_id); 1567 1568 if (mux_client_write_packet(fd, &m) != 0) 1569 fatal("%s: write packet: %s", __func__, strerror(errno)); 1570 1571 buffer_clear(&m); 1572 1573 /* Read their reply */ 1574 if (mux_client_read_packet(fd, &m) != 0) { 1575 /* Remote end exited already */ 1576 if (errno == EPIPE) { 1577 buffer_free(&m); 1578 return; 1579 } 1580 fatal("%s: read from master failed: %s", 1581 __func__, strerror(errno)); 1582 } 1583 1584 type = buffer_get_int(&m); 1585 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1586 fatal("%s: out of sequence reply: my id %u theirs %u", 1587 __func__, muxclient_request_id, rid); 1588 switch (type) { 1589 case MUX_S_OK: 1590 break; 1591 case MUX_S_PERMISSION_DENIED: 1592 e = buffer_get_string(&m, NULL); 1593 fatal("Master refused termination request: %s", e); 1594 case MUX_S_FAILURE: 1595 e = buffer_get_string(&m, NULL); 1596 fatal("%s: termination request failed: %s", __func__, e); 1597 default: 1598 fatal("%s: unexpected response from master 0x%08x", 1599 __func__, type); 1600 } 1601 buffer_free(&m); 1602 muxclient_request_id++; 1603 } 1604 1605 static int 1606 mux_client_forward(int fd, int cancel_flag, u_int ftype, Forward *fwd) 1607 { 1608 Buffer m; 1609 char *e, *fwd_desc; 1610 u_int type, rid; 1611 1612 fwd_desc = format_forward(ftype, fwd); 1613 debug("Requesting %s %s", 1614 cancel_flag ? "cancellation of" : "forwarding of", fwd_desc); 1615 xfree(fwd_desc); 1616 1617 buffer_init(&m); 1618 buffer_put_int(&m, cancel_flag ? MUX_C_CLOSE_FWD : MUX_C_OPEN_FWD); 1619 buffer_put_int(&m, muxclient_request_id); 1620 buffer_put_int(&m, ftype); 1621 buffer_put_cstring(&m, 1622 fwd->listen_host == NULL ? "" : fwd->listen_host); 1623 buffer_put_int(&m, fwd->listen_port); 1624 buffer_put_cstring(&m, 1625 fwd->connect_host == NULL ? "" : fwd->connect_host); 1626 buffer_put_int(&m, fwd->connect_port); 1627 1628 if (mux_client_write_packet(fd, &m) != 0) 1629 fatal("%s: write packet: %s", __func__, strerror(errno)); 1630 1631 buffer_clear(&m); 1632 1633 /* Read their reply */ 1634 if (mux_client_read_packet(fd, &m) != 0) { 1635 buffer_free(&m); 1636 return -1; 1637 } 1638 1639 type = buffer_get_int(&m); 1640 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1641 fatal("%s: out of sequence reply: my id %u theirs %u", 1642 __func__, muxclient_request_id, rid); 1643 switch (type) { 1644 case MUX_S_OK: 1645 break; 1646 case MUX_S_REMOTE_PORT: 1647 if (cancel_flag) 1648 fatal("%s: got MUX_S_REMOTE_PORT for cancel", __func__); 1649 fwd->allocated_port = buffer_get_int(&m); 1650 logit("Allocated port %u for remote forward to %s:%d", 1651 fwd->allocated_port, 1652 fwd->connect_host ? fwd->connect_host : "", 1653 fwd->connect_port); 1654 if (muxclient_command == SSHMUX_COMMAND_FORWARD) 1655 fprintf(stdout, "%u\n", fwd->allocated_port); 1656 break; 1657 case MUX_S_PERMISSION_DENIED: 1658 e = buffer_get_string(&m, NULL); 1659 buffer_free(&m); 1660 error("Master refused forwarding request: %s", e); 1661 return -1; 1662 case MUX_S_FAILURE: 1663 e = buffer_get_string(&m, NULL); 1664 buffer_free(&m); 1665 error("%s: forwarding request failed: %s", __func__, e); 1666 return -1; 1667 default: 1668 fatal("%s: unexpected response from master 0x%08x", 1669 __func__, type); 1670 } 1671 buffer_free(&m); 1672 1673 muxclient_request_id++; 1674 return 0; 1675 } 1676 1677 static int 1678 mux_client_forwards(int fd, int cancel_flag) 1679 { 1680 int i, ret = 0; 1681 1682 debug3("%s: %s forwardings: %d local, %d remote", __func__, 1683 cancel_flag ? "cancel" : "request", 1684 options.num_local_forwards, options.num_remote_forwards); 1685 1686 /* XXX ExitOnForwardingFailure */ 1687 for (i = 0; i < options.num_local_forwards; i++) { 1688 if (mux_client_forward(fd, cancel_flag, 1689 options.local_forwards[i].connect_port == 0 ? 1690 MUX_FWD_DYNAMIC : MUX_FWD_LOCAL, 1691 options.local_forwards + i) != 0) 1692 ret = -1; 1693 } 1694 for (i = 0; i < options.num_remote_forwards; i++) { 1695 if (mux_client_forward(fd, cancel_flag, MUX_FWD_REMOTE, 1696 options.remote_forwards + i) != 0) 1697 ret = -1; 1698 } 1699 return ret; 1700 } 1701 1702 static int 1703 mux_client_request_session(int fd) 1704 { 1705 Buffer m; 1706 char *e, *term; 1707 u_int i, rid, sid, esid, exitval, type, exitval_seen; 1708 extern char **environ; 1709 int devnull, rawmode; 1710 1711 debug3("%s: entering", __func__); 1712 1713 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) { 1714 error("%s: master alive request failed", __func__); 1715 return -1; 1716 } 1717 1718 signal(SIGPIPE, SIG_IGN); 1719 1720 if (stdin_null_flag) { 1721 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1722 fatal("open(/dev/null): %s", strerror(errno)); 1723 if (dup2(devnull, STDIN_FILENO) == -1) 1724 fatal("dup2: %s", strerror(errno)); 1725 if (devnull > STDERR_FILENO) 1726 close(devnull); 1727 } 1728 1729 term = getenv("TERM"); 1730 1731 buffer_init(&m); 1732 buffer_put_int(&m, MUX_C_NEW_SESSION); 1733 buffer_put_int(&m, muxclient_request_id); 1734 buffer_put_cstring(&m, ""); /* reserved */ 1735 buffer_put_int(&m, tty_flag); 1736 buffer_put_int(&m, options.forward_x11); 1737 buffer_put_int(&m, options.forward_agent); 1738 buffer_put_int(&m, subsystem_flag); 1739 buffer_put_int(&m, options.escape_char == SSH_ESCAPECHAR_NONE ? 1740 0xffffffff : (u_int)options.escape_char); 1741 buffer_put_cstring(&m, term == NULL ? "" : term); 1742 buffer_put_string(&m, buffer_ptr(&command), buffer_len(&command)); 1743 1744 if (options.num_send_env > 0 && environ != NULL) { 1745 /* Pass environment */ 1746 for (i = 0; environ[i] != NULL; i++) { 1747 if (env_permitted(environ[i])) { 1748 buffer_put_cstring(&m, environ[i]); 1749 } 1750 } 1751 } 1752 1753 if (mux_client_write_packet(fd, &m) != 0) 1754 fatal("%s: write packet: %s", __func__, strerror(errno)); 1755 1756 /* Send the stdio file descriptors */ 1757 if (mm_send_fd(fd, STDIN_FILENO) == -1 || 1758 mm_send_fd(fd, STDOUT_FILENO) == -1 || 1759 mm_send_fd(fd, STDERR_FILENO) == -1) 1760 fatal("%s: send fds failed", __func__); 1761 1762 debug3("%s: session request sent", __func__); 1763 1764 /* Read their reply */ 1765 buffer_clear(&m); 1766 if (mux_client_read_packet(fd, &m) != 0) { 1767 error("%s: read from master failed: %s", 1768 __func__, strerror(errno)); 1769 buffer_free(&m); 1770 return -1; 1771 } 1772 1773 type = buffer_get_int(&m); 1774 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1775 fatal("%s: out of sequence reply: my id %u theirs %u", 1776 __func__, muxclient_request_id, rid); 1777 switch (type) { 1778 case MUX_S_SESSION_OPENED: 1779 sid = buffer_get_int(&m); 1780 debug("%s: master session id: %u", __func__, sid); 1781 break; 1782 case MUX_S_PERMISSION_DENIED: 1783 e = buffer_get_string(&m, NULL); 1784 buffer_free(&m); 1785 error("Master refused session request: %s", e); 1786 return -1; 1787 case MUX_S_FAILURE: 1788 e = buffer_get_string(&m, NULL); 1789 buffer_free(&m); 1790 error("%s: session request failed: %s", __func__, e); 1791 return -1; 1792 default: 1793 buffer_free(&m); 1794 error("%s: unexpected response from master 0x%08x", 1795 __func__, type); 1796 return -1; 1797 } 1798 muxclient_request_id++; 1799 1800 signal(SIGHUP, control_client_sighandler); 1801 signal(SIGINT, control_client_sighandler); 1802 signal(SIGTERM, control_client_sighandler); 1803 signal(SIGWINCH, control_client_sigrelay); 1804 1805 rawmode = tty_flag; 1806 if (tty_flag) 1807 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1808 1809 /* 1810 * Stick around until the controlee closes the client_fd. 1811 * Before it does, it is expected to write an exit message. 1812 * This process must read the value and wait for the closure of 1813 * the client_fd; if this one closes early, the multiplex master will 1814 * terminate early too (possibly losing data). 1815 */ 1816 for (exitval = 255, exitval_seen = 0;;) { 1817 buffer_clear(&m); 1818 if (mux_client_read_packet(fd, &m) != 0) 1819 break; 1820 type = buffer_get_int(&m); 1821 switch (type) { 1822 case MUX_S_TTY_ALLOC_FAIL: 1823 if ((esid = buffer_get_int(&m)) != sid) 1824 fatal("%s: tty alloc fail on unknown session: " 1825 "my id %u theirs %u", 1826 __func__, sid, esid); 1827 leave_raw_mode(options.request_tty == 1828 REQUEST_TTY_FORCE); 1829 rawmode = 0; 1830 continue; 1831 case MUX_S_EXIT_MESSAGE: 1832 if ((esid = buffer_get_int(&m)) != sid) 1833 fatal("%s: exit on unknown session: " 1834 "my id %u theirs %u", 1835 __func__, sid, esid); 1836 if (exitval_seen) 1837 fatal("%s: exitval sent twice", __func__); 1838 exitval = buffer_get_int(&m); 1839 exitval_seen = 1; 1840 continue; 1841 default: 1842 e = buffer_get_string(&m, NULL); 1843 fatal("%s: master returned error: %s", __func__, e); 1844 } 1845 } 1846 1847 close(fd); 1848 if (rawmode) 1849 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1850 1851 if (muxclient_terminate) { 1852 debug2("Exiting on signal %d", muxclient_terminate); 1853 exitval = 255; 1854 } else if (!exitval_seen) { 1855 debug2("Control master terminated unexpectedly"); 1856 exitval = 255; 1857 } else 1858 debug2("Received exit status from master %d", exitval); 1859 1860 if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET) 1861 fprintf(stderr, "Shared connection to %s closed.\r\n", host); 1862 1863 exit(exitval); 1864 } 1865 1866 static int 1867 mux_client_request_stdio_fwd(int fd) 1868 { 1869 Buffer m; 1870 char *e; 1871 u_int type, rid, sid; 1872 int devnull; 1873 1874 debug3("%s: entering", __func__); 1875 1876 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) { 1877 error("%s: master alive request failed", __func__); 1878 return -1; 1879 } 1880 1881 signal(SIGPIPE, SIG_IGN); 1882 1883 if (stdin_null_flag) { 1884 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1885 fatal("open(/dev/null): %s", strerror(errno)); 1886 if (dup2(devnull, STDIN_FILENO) == -1) 1887 fatal("dup2: %s", strerror(errno)); 1888 if (devnull > STDERR_FILENO) 1889 close(devnull); 1890 } 1891 1892 buffer_init(&m); 1893 buffer_put_int(&m, MUX_C_NEW_STDIO_FWD); 1894 buffer_put_int(&m, muxclient_request_id); 1895 buffer_put_cstring(&m, ""); /* reserved */ 1896 buffer_put_cstring(&m, stdio_forward_host); 1897 buffer_put_int(&m, stdio_forward_port); 1898 1899 if (mux_client_write_packet(fd, &m) != 0) 1900 fatal("%s: write packet: %s", __func__, strerror(errno)); 1901 1902 /* Send the stdio file descriptors */ 1903 if (mm_send_fd(fd, STDIN_FILENO) == -1 || 1904 mm_send_fd(fd, STDOUT_FILENO) == -1) 1905 fatal("%s: send fds failed", __func__); 1906 1907 debug3("%s: stdio forward request sent", __func__); 1908 1909 /* Read their reply */ 1910 buffer_clear(&m); 1911 1912 if (mux_client_read_packet(fd, &m) != 0) { 1913 error("%s: read from master failed: %s", 1914 __func__, strerror(errno)); 1915 buffer_free(&m); 1916 return -1; 1917 } 1918 1919 type = buffer_get_int(&m); 1920 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1921 fatal("%s: out of sequence reply: my id %u theirs %u", 1922 __func__, muxclient_request_id, rid); 1923 switch (type) { 1924 case MUX_S_SESSION_OPENED: 1925 sid = buffer_get_int(&m); 1926 debug("%s: master session id: %u", __func__, sid); 1927 break; 1928 case MUX_S_PERMISSION_DENIED: 1929 e = buffer_get_string(&m, NULL); 1930 buffer_free(&m); 1931 fatal("Master refused stdio forwarding request: %s", e); 1932 case MUX_S_FAILURE: 1933 e = buffer_get_string(&m, NULL); 1934 buffer_free(&m); 1935 fatal("%s: stdio forwarding request failed: %s", __func__, e); 1936 default: 1937 buffer_free(&m); 1938 error("%s: unexpected response from master 0x%08x", 1939 __func__, type); 1940 return -1; 1941 } 1942 muxclient_request_id++; 1943 1944 signal(SIGHUP, control_client_sighandler); 1945 signal(SIGINT, control_client_sighandler); 1946 signal(SIGTERM, control_client_sighandler); 1947 signal(SIGWINCH, control_client_sigrelay); 1948 1949 /* 1950 * Stick around until the controlee closes the client_fd. 1951 */ 1952 buffer_clear(&m); 1953 if (mux_client_read_packet(fd, &m) != 0) { 1954 if (errno == EPIPE || 1955 (errno == EINTR && muxclient_terminate != 0)) 1956 return 0; 1957 fatal("%s: mux_client_read_packet: %s", 1958 __func__, strerror(errno)); 1959 } 1960 fatal("%s: master returned unexpected message %u", __func__, type); 1961 } 1962 1963 static void 1964 mux_client_request_stop_listening(int fd) 1965 { 1966 Buffer m; 1967 char *e; 1968 u_int type, rid; 1969 1970 debug3("%s: entering", __func__); 1971 1972 buffer_init(&m); 1973 buffer_put_int(&m, MUX_C_STOP_LISTENING); 1974 buffer_put_int(&m, muxclient_request_id); 1975 1976 if (mux_client_write_packet(fd, &m) != 0) 1977 fatal("%s: write packet: %s", __func__, strerror(errno)); 1978 1979 buffer_clear(&m); 1980 1981 /* Read their reply */ 1982 if (mux_client_read_packet(fd, &m) != 0) 1983 fatal("%s: read from master failed: %s", 1984 __func__, strerror(errno)); 1985 1986 type = buffer_get_int(&m); 1987 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1988 fatal("%s: out of sequence reply: my id %u theirs %u", 1989 __func__, muxclient_request_id, rid); 1990 switch (type) { 1991 case MUX_S_OK: 1992 break; 1993 case MUX_S_PERMISSION_DENIED: 1994 e = buffer_get_string(&m, NULL); 1995 fatal("Master refused stop listening request: %s", e); 1996 case MUX_S_FAILURE: 1997 e = buffer_get_string(&m, NULL); 1998 fatal("%s: stop listening request failed: %s", __func__, e); 1999 default: 2000 fatal("%s: unexpected response from master 0x%08x", 2001 __func__, type); 2002 } 2003 buffer_free(&m); 2004 muxclient_request_id++; 2005 } 2006 2007 /* Multiplex client main loop. */ 2008 void 2009 muxclient(const char *path) 2010 { 2011 struct sockaddr_un addr; 2012 socklen_t sun_len; 2013 int sock; 2014 u_int pid; 2015 2016 if (muxclient_command == 0) { 2017 if (stdio_forward_host != NULL) 2018 muxclient_command = SSHMUX_COMMAND_STDIO_FWD; 2019 else 2020 muxclient_command = SSHMUX_COMMAND_OPEN; 2021 } 2022 2023 switch (options.control_master) { 2024 case SSHCTL_MASTER_AUTO: 2025 case SSHCTL_MASTER_AUTO_ASK: 2026 debug("auto-mux: Trying existing master"); 2027 /* FALLTHROUGH */ 2028 case SSHCTL_MASTER_NO: 2029 break; 2030 default: 2031 return; 2032 } 2033 2034 memset(&addr, '\0', sizeof(addr)); 2035 addr.sun_family = AF_UNIX; 2036 sun_len = offsetof(struct sockaddr_un, sun_path) + 2037 strlen(path) + 1; 2038 2039 if (strlcpy(addr.sun_path, path, 2040 sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) 2041 fatal("ControlPath too long"); 2042 2043 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) 2044 fatal("%s socket(): %s", __func__, strerror(errno)); 2045 2046 if (connect(sock, (struct sockaddr *)&addr, sun_len) == -1) { 2047 switch (muxclient_command) { 2048 case SSHMUX_COMMAND_OPEN: 2049 case SSHMUX_COMMAND_STDIO_FWD: 2050 break; 2051 default: 2052 fatal("Control socket connect(%.100s): %s", path, 2053 strerror(errno)); 2054 } 2055 if (errno == ECONNREFUSED && 2056 options.control_master != SSHCTL_MASTER_NO) { 2057 debug("Stale control socket %.100s, unlinking", path); 2058 unlink(path); 2059 } else if (errno == ENOENT) { 2060 debug("Control socket \"%.100s\" does not exist", path); 2061 } else { 2062 error("Control socket connect(%.100s): %s", path, 2063 strerror(errno)); 2064 } 2065 close(sock); 2066 return; 2067 } 2068 set_nonblock(sock); 2069 2070 if (mux_client_hello_exchange(sock) != 0) { 2071 error("%s: master hello exchange failed", __func__); 2072 close(sock); 2073 return; 2074 } 2075 2076 switch (muxclient_command) { 2077 case SSHMUX_COMMAND_ALIVE_CHECK: 2078 if ((pid = mux_client_request_alive(sock)) == 0) 2079 fatal("%s: master alive check failed", __func__); 2080 fprintf(stderr, "Master running (pid=%d)\r\n", pid); 2081 exit(0); 2082 case SSHMUX_COMMAND_TERMINATE: 2083 mux_client_request_terminate(sock); 2084 fprintf(stderr, "Exit request sent.\r\n"); 2085 exit(0); 2086 case SSHMUX_COMMAND_FORWARD: 2087 if (mux_client_forwards(sock, 0) != 0) 2088 fatal("%s: master forward request failed", __func__); 2089 exit(0); 2090 case SSHMUX_COMMAND_OPEN: 2091 if (mux_client_forwards(sock, 0) != 0) { 2092 error("%s: master forward request failed", __func__); 2093 return; 2094 } 2095 mux_client_request_session(sock); 2096 return; 2097 case SSHMUX_COMMAND_STDIO_FWD: 2098 mux_client_request_stdio_fwd(sock); 2099 exit(0); 2100 case SSHMUX_COMMAND_STOP: 2101 mux_client_request_stop_listening(sock); 2102 fprintf(stderr, "Stop listening request sent.\r\n"); 2103 exit(0); 2104 case SSHMUX_COMMAND_CANCEL_FWD: 2105 if (mux_client_forwards(sock, 1) != 0) 2106 error("%s: master cancel forward request failed", 2107 __func__); 2108 exit(0); 2109 default: 2110 fatal("unrecognised muxclient_command %d", muxclient_command); 2111 } 2112 } 2113