1 /* $NetBSD: mux.c,v 1.9 2013/11/08 19:18:25 christos Exp $ */ 2 /* $OpenBSD: mux.c,v 1.44 2013/07/12 00:19:58 djm Exp $ */ 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("$NetBSD: mux.c,v 1.9 2013/11/08 19:18:25 christos Exp $"); 36 #include <sys/types.h> 37 #include <sys/param.h> 38 #include <sys/queue.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 <poll.h> 46 #include <signal.h> 47 #include <stdarg.h> 48 #include <stddef.h> 49 #include <stdlib.h> 50 #include <stdio.h> 51 #include <string.h> 52 #include <unistd.h> 53 #include <util.h> 54 #include <paths.h> 55 56 #include "atomicio.h" 57 #include "xmalloc.h" 58 #include "log.h" 59 #include "ssh.h" 60 #include "ssh2.h" 61 #include "pathnames.h" 62 #include "misc.h" 63 #include "match.h" 64 #include "buffer.h" 65 #include "channels.h" 66 #include "msg.h" 67 #include "packet.h" 68 #include "monitor_fdpass.h" 69 #include "sshpty.h" 70 #include "key.h" 71 #include "readconf.h" 72 #include "clientloop.h" 73 74 /* from ssh.c */ 75 extern int tty_flag; 76 extern Options options; 77 extern int stdin_null_flag; 78 extern char *host; 79 extern int subsystem_flag; 80 extern Buffer command; 81 extern volatile sig_atomic_t quit_pending; 82 extern char *stdio_forward_host; 83 extern int stdio_forward_port; 84 85 /* Context for session open confirmation callback */ 86 struct mux_session_confirm_ctx { 87 u_int want_tty; 88 u_int want_subsys; 89 u_int want_x_fwd; 90 u_int want_agent_fwd; 91 Buffer cmd; 92 char *term; 93 struct termios tio; 94 char **env; 95 u_int rid; 96 }; 97 98 /* Context for global channel callback */ 99 struct mux_channel_confirm_ctx { 100 u_int cid; /* channel id */ 101 u_int rid; /* request id */ 102 int fid; /* forward id */ 103 }; 104 105 /* fd to control socket */ 106 int muxserver_sock = -1; 107 108 /* client request id */ 109 u_int muxclient_request_id = 0; 110 111 /* Multiplexing control command */ 112 u_int muxclient_command = 0; 113 114 /* Set when signalled. */ 115 static volatile sig_atomic_t muxclient_terminate = 0; 116 117 /* PID of multiplex server */ 118 static u_int muxserver_pid = 0; 119 120 static Channel *mux_listener_channel = NULL; 121 122 struct mux_master_state { 123 int hello_rcvd; 124 }; 125 126 /* mux protocol messages */ 127 #define MUX_MSG_HELLO 0x00000001 128 #define MUX_C_NEW_SESSION 0x10000002 129 #define MUX_C_ALIVE_CHECK 0x10000004 130 #define MUX_C_TERMINATE 0x10000005 131 #define MUX_C_OPEN_FWD 0x10000006 132 #define MUX_C_CLOSE_FWD 0x10000007 133 #define MUX_C_NEW_STDIO_FWD 0x10000008 134 #define MUX_C_STOP_LISTENING 0x10000009 135 #define MUX_S_OK 0x80000001 136 #define MUX_S_PERMISSION_DENIED 0x80000002 137 #define MUX_S_FAILURE 0x80000003 138 #define MUX_S_EXIT_MESSAGE 0x80000004 139 #define MUX_S_ALIVE 0x80000005 140 #define MUX_S_SESSION_OPENED 0x80000006 141 #define MUX_S_REMOTE_PORT 0x80000007 142 #define MUX_S_TTY_ALLOC_FAIL 0x80000008 143 144 /* type codes for MUX_C_OPEN_FWD and MUX_C_CLOSE_FWD */ 145 #define MUX_FWD_LOCAL 1 146 #define MUX_FWD_REMOTE 2 147 #define MUX_FWD_DYNAMIC 3 148 149 static void mux_session_confirm(int, int, void *); 150 151 static int process_mux_master_hello(u_int, Channel *, Buffer *, Buffer *); 152 static int process_mux_new_session(u_int, Channel *, Buffer *, Buffer *); 153 static int process_mux_alive_check(u_int, Channel *, Buffer *, Buffer *); 154 static int process_mux_terminate(u_int, Channel *, Buffer *, Buffer *); 155 static int process_mux_open_fwd(u_int, Channel *, Buffer *, Buffer *); 156 static int process_mux_close_fwd(u_int, Channel *, Buffer *, Buffer *); 157 static int process_mux_stdio_fwd(u_int, Channel *, Buffer *, Buffer *); 158 static int process_mux_stop_listening(u_int, Channel *, Buffer *, Buffer *); 159 160 static const struct { 161 u_int type; 162 int (*handler)(u_int, Channel *, Buffer *, Buffer *); 163 } mux_master_handlers[] = { 164 { MUX_MSG_HELLO, process_mux_master_hello }, 165 { MUX_C_NEW_SESSION, process_mux_new_session }, 166 { MUX_C_ALIVE_CHECK, process_mux_alive_check }, 167 { MUX_C_TERMINATE, process_mux_terminate }, 168 { MUX_C_OPEN_FWD, process_mux_open_fwd }, 169 { MUX_C_CLOSE_FWD, process_mux_close_fwd }, 170 { MUX_C_NEW_STDIO_FWD, process_mux_stdio_fwd }, 171 { MUX_C_STOP_LISTENING, process_mux_stop_listening }, 172 { 0, NULL } 173 }; 174 175 /* Cleanup callback fired on closure of mux slave _session_ channel */ 176 /* ARGSUSED */ 177 static void 178 mux_master_session_cleanup_cb(int cid, void *unused) 179 { 180 Channel *cc, *c = channel_by_id(cid); 181 182 debug3("%s: entering for channel %d", __func__, cid); 183 if (c == NULL) 184 fatal("%s: channel_by_id(%i) == NULL", __func__, cid); 185 if (c->ctl_chan != -1) { 186 if ((cc = channel_by_id(c->ctl_chan)) == NULL) 187 fatal("%s: channel %d missing control channel %d", 188 __func__, c->self, c->ctl_chan); 189 c->ctl_chan = -1; 190 cc->remote_id = -1; 191 chan_rcvd_oclose(cc); 192 } 193 channel_cancel_cleanup(c->self); 194 } 195 196 /* Cleanup callback fired on closure of mux slave _control_ channel */ 197 /* ARGSUSED */ 198 static void 199 mux_master_control_cleanup_cb(int cid, void *unused) 200 { 201 Channel *sc, *c = channel_by_id(cid); 202 203 debug3("%s: entering for channel %d", __func__, cid); 204 if (c == NULL) 205 fatal("%s: channel_by_id(%i) == NULL", __func__, cid); 206 if (c->remote_id != -1) { 207 if ((sc = channel_by_id(c->remote_id)) == NULL) 208 fatal("%s: channel %d missing session channel %d", 209 __func__, c->self, c->remote_id); 210 c->remote_id = -1; 211 sc->ctl_chan = -1; 212 if (sc->type != SSH_CHANNEL_OPEN && 213 sc->type != SSH_CHANNEL_OPENING) { 214 debug2("%s: channel %d: not open", __func__, sc->self); 215 chan_mark_dead(sc); 216 } else { 217 if (sc->istate == CHAN_INPUT_OPEN) 218 chan_read_failed(sc); 219 if (sc->ostate == CHAN_OUTPUT_OPEN) 220 chan_write_failed(sc); 221 } 222 } 223 channel_cancel_cleanup(c->self); 224 } 225 226 /* Check mux client environment variables before passing them to mux master. */ 227 static int 228 env_permitted(char *env) 229 { 230 int i, ret; 231 char name[1024], *cp; 232 233 if ((cp = strchr(env, '=')) == NULL || cp == env) 234 return 0; 235 ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env); 236 if (ret <= 0 || (size_t)ret >= sizeof(name)) { 237 error("env_permitted: name '%.100s...' too long", env); 238 return 0; 239 } 240 241 for (i = 0; i < options.num_send_env; i++) 242 if (match_pattern(name, options.send_env[i])) 243 return 1; 244 245 return 0; 246 } 247 248 /* Mux master protocol message handlers */ 249 250 static int 251 process_mux_master_hello(u_int rid, Channel *c, Buffer *m, Buffer *r) 252 { 253 u_int ver; 254 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx; 255 256 if (state == NULL) 257 fatal("%s: channel %d: c->mux_ctx == NULL", __func__, c->self); 258 if (state->hello_rcvd) { 259 error("%s: HELLO received twice", __func__); 260 return -1; 261 } 262 if (buffer_get_int_ret(&ver, m) != 0) { 263 malf: 264 error("%s: malformed message", __func__); 265 return -1; 266 } 267 if (ver != SSHMUX_VER) { 268 error("Unsupported multiplexing protocol version %d " 269 "(expected %d)", ver, SSHMUX_VER); 270 return -1; 271 } 272 debug2("%s: channel %d slave version %u", __func__, c->self, ver); 273 274 /* No extensions are presently defined */ 275 while (buffer_len(m) > 0) { 276 char *name = buffer_get_string_ret(m, NULL); 277 char *value = buffer_get_string_ret(m, NULL); 278 279 if (name == NULL || value == NULL) { 280 free(name); 281 free(value); 282 goto malf; 283 } 284 debug2("Unrecognised slave extension \"%s\"", name); 285 free(name); 286 free(value); 287 } 288 state->hello_rcvd = 1; 289 return 0; 290 } 291 292 static int 293 process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r) 294 { 295 Channel *nc; 296 struct mux_session_confirm_ctx *cctx; 297 char *reserved, *cmd, *cp; 298 u_int i, j, len, env_len, escape_char, window, packetmax; 299 int new_fd[3]; 300 301 /* Reply for SSHMUX_COMMAND_OPEN */ 302 cctx = xcalloc(1, sizeof(*cctx)); 303 cctx->term = NULL; 304 cctx->rid = rid; 305 cmd = reserved = NULL; 306 cctx->env = NULL; 307 env_len = 0; 308 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL || 309 buffer_get_int_ret(&cctx->want_tty, m) != 0 || 310 buffer_get_int_ret(&cctx->want_x_fwd, m) != 0 || 311 buffer_get_int_ret(&cctx->want_agent_fwd, m) != 0 || 312 buffer_get_int_ret(&cctx->want_subsys, m) != 0 || 313 buffer_get_int_ret(&escape_char, m) != 0 || 314 (cctx->term = buffer_get_string_ret(m, &len)) == NULL || 315 (cmd = buffer_get_string_ret(m, &len)) == NULL) { 316 malf: 317 free(cmd); 318 free(reserved); 319 for (j = 0; j < env_len; j++) 320 free(cctx->env[j]); 321 free(cctx->env); 322 free(cctx->term); 323 free(cctx); 324 error("%s: malformed message", __func__); 325 return -1; 326 } 327 free(reserved); 328 reserved = NULL; 329 330 while (buffer_len(m) > 0) { 331 #define MUX_MAX_ENV_VARS 4096 332 if ((cp = buffer_get_string_ret(m, &len)) == NULL) 333 goto malf; 334 if (!env_permitted(cp)) { 335 free(cp); 336 continue; 337 } 338 cctx->env = xrealloc(cctx->env, env_len + 2, 339 sizeof(*cctx->env)); 340 cctx->env[env_len++] = cp; 341 cctx->env[env_len] = NULL; 342 if (env_len > MUX_MAX_ENV_VARS) { 343 error(">%d environment variables received, ignoring " 344 "additional", MUX_MAX_ENV_VARS); 345 break; 346 } 347 } 348 349 debug2("%s: channel %d: request tty %d, X %d, agent %d, subsys %d, " 350 "term \"%s\", cmd \"%s\", env %u", __func__, c->self, 351 cctx->want_tty, cctx->want_x_fwd, cctx->want_agent_fwd, 352 cctx->want_subsys, cctx->term, cmd, env_len); 353 354 buffer_init(&cctx->cmd); 355 buffer_append(&cctx->cmd, cmd, strlen(cmd)); 356 free(cmd); 357 cmd = NULL; 358 359 /* Gather fds from client */ 360 for(i = 0; i < 3; i++) { 361 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) { 362 error("%s: failed to receive fd %d from slave", 363 __func__, i); 364 for (j = 0; j < i; j++) 365 close(new_fd[j]); 366 for (j = 0; j < env_len; j++) 367 free(cctx->env[j]); 368 free(cctx->env); 369 free(cctx->term); 370 buffer_free(&cctx->cmd); 371 free(cctx); 372 373 /* prepare reply */ 374 buffer_put_int(r, MUX_S_FAILURE); 375 buffer_put_int(r, rid); 376 buffer_put_cstring(r, 377 "did not receive file descriptors"); 378 return -1; 379 } 380 } 381 382 debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__, 383 new_fd[0], new_fd[1], new_fd[2]); 384 385 /* XXX support multiple child sessions in future */ 386 if (c->remote_id != -1) { 387 debug2("%s: session already open", __func__); 388 /* prepare reply */ 389 buffer_put_int(r, MUX_S_FAILURE); 390 buffer_put_int(r, rid); 391 buffer_put_cstring(r, "Multiple sessions not supported"); 392 cleanup: 393 close(new_fd[0]); 394 close(new_fd[1]); 395 close(new_fd[2]); 396 free(cctx->term); 397 if (env_len != 0) { 398 for (i = 0; i < env_len; i++) 399 free(cctx->env[i]); 400 free(cctx->env); 401 } 402 buffer_free(&cctx->cmd); 403 free(cctx); 404 return 0; 405 } 406 407 if (options.control_master == SSHCTL_MASTER_ASK || 408 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 409 if (!ask_permission("Allow shared connection to %s? ", host)) { 410 debug2("%s: session refused by user", __func__); 411 /* prepare reply */ 412 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 413 buffer_put_int(r, rid); 414 buffer_put_cstring(r, "Permission denied"); 415 goto cleanup; 416 } 417 } 418 419 /* Try to pick up ttymodes from client before it goes raw */ 420 if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1) 421 error("%s: tcgetattr: %s", __func__, strerror(errno)); 422 423 /* enable nonblocking unless tty */ 424 if (!isatty(new_fd[0])) 425 set_nonblock(new_fd[0]); 426 if (!isatty(new_fd[1])) 427 set_nonblock(new_fd[1]); 428 if (!isatty(new_fd[2])) 429 set_nonblock(new_fd[2]); 430 431 window = CHAN_SES_WINDOW_DEFAULT; 432 packetmax = CHAN_SES_PACKET_DEFAULT; 433 if (cctx->want_tty) { 434 window >>= 1; 435 packetmax >>= 1; 436 } 437 438 nc = channel_new("session", SSH_CHANNEL_OPENING, 439 new_fd[0], new_fd[1], new_fd[2], window, packetmax, 440 CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); 441 442 nc->ctl_chan = c->self; /* link session -> control channel */ 443 c->remote_id = nc->self; /* link control -> session channel */ 444 445 if (cctx->want_tty && escape_char != 0xffffffff) { 446 channel_register_filter(nc->self, 447 client_simple_escape_filter, NULL, 448 client_filter_cleanup, 449 client_new_escape_filter_ctx((int)escape_char)); 450 } 451 452 debug2("%s: channel_new: %d linked to control channel %d", 453 __func__, nc->self, nc->ctl_chan); 454 455 channel_send_open(nc->self); 456 channel_register_open_confirm(nc->self, mux_session_confirm, cctx); 457 c->mux_pause = 1; /* stop handling messages until open_confirm done */ 458 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1); 459 460 /* reply is deferred, sent by mux_session_confirm */ 461 return 0; 462 } 463 464 static int 465 process_mux_alive_check(u_int rid, Channel *c, Buffer *m, Buffer *r) 466 { 467 debug2("%s: channel %d: alive check", __func__, c->self); 468 469 /* prepare reply */ 470 buffer_put_int(r, MUX_S_ALIVE); 471 buffer_put_int(r, rid); 472 buffer_put_int(r, (u_int)getpid()); 473 474 return 0; 475 } 476 477 static int 478 process_mux_terminate(u_int rid, Channel *c, Buffer *m, Buffer *r) 479 { 480 debug2("%s: channel %d: terminate request", __func__, c->self); 481 482 if (options.control_master == SSHCTL_MASTER_ASK || 483 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 484 if (!ask_permission("Terminate shared connection to %s? ", 485 host)) { 486 debug2("%s: termination refused by user", __func__); 487 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 488 buffer_put_int(r, rid); 489 buffer_put_cstring(r, "Permission denied"); 490 return 0; 491 } 492 } 493 494 quit_pending = 1; 495 buffer_put_int(r, MUX_S_OK); 496 buffer_put_int(r, rid); 497 /* XXX exit happens too soon - message never makes it to client */ 498 return 0; 499 } 500 501 static char * 502 format_forward(u_int ftype, Forward *fwd) 503 { 504 char *ret; 505 506 switch (ftype) { 507 case MUX_FWD_LOCAL: 508 xasprintf(&ret, "local forward %.200s:%d -> %.200s:%d", 509 (fwd->listen_host == NULL) ? 510 (options.gateway_ports ? "*" : "LOCALHOST") : 511 fwd->listen_host, fwd->listen_port, 512 fwd->connect_host, fwd->connect_port); 513 break; 514 case MUX_FWD_DYNAMIC: 515 xasprintf(&ret, "dynamic forward %.200s:%d -> *", 516 (fwd->listen_host == NULL) ? 517 (options.gateway_ports ? "*" : "LOCALHOST") : 518 fwd->listen_host, fwd->listen_port); 519 break; 520 case MUX_FWD_REMOTE: 521 xasprintf(&ret, "remote forward %.200s:%d -> %.200s:%d", 522 (fwd->listen_host == NULL) ? 523 "LOCALHOST" : fwd->listen_host, 524 fwd->listen_port, 525 fwd->connect_host, fwd->connect_port); 526 break; 527 default: 528 fatal("%s: unknown forward type %u", __func__, ftype); 529 } 530 return ret; 531 } 532 533 static int 534 compare_host(const char *a, const char *b) 535 { 536 if (a == NULL && b == NULL) 537 return 1; 538 if (a == NULL || b == NULL) 539 return 0; 540 return strcmp(a, b) == 0; 541 } 542 543 static int 544 compare_forward(Forward *a, Forward *b) 545 { 546 if (!compare_host(a->listen_host, b->listen_host)) 547 return 0; 548 if (a->listen_port != b->listen_port) 549 return 0; 550 if (!compare_host(a->connect_host, b->connect_host)) 551 return 0; 552 if (a->connect_port != b->connect_port) 553 return 0; 554 555 return 1; 556 } 557 558 static void 559 mux_confirm_remote_forward(int type, u_int32_t seq, void *ctxt) 560 { 561 struct mux_channel_confirm_ctx *fctx = ctxt; 562 char *failmsg = NULL; 563 Forward *rfwd; 564 Channel *c; 565 Buffer out; 566 567 if ((c = channel_by_id(fctx->cid)) == NULL) { 568 /* no channel for reply */ 569 error("%s: unknown channel", __func__); 570 return; 571 } 572 buffer_init(&out); 573 if (fctx->fid >= options.num_remote_forwards) { 574 xasprintf(&failmsg, "unknown forwarding id %d", fctx->fid); 575 goto fail; 576 } 577 rfwd = &options.remote_forwards[fctx->fid]; 578 debug("%s: %s for: listen %d, connect %s:%d", __func__, 579 type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", 580 rfwd->listen_port, rfwd->connect_host, rfwd->connect_port); 581 if (type == SSH2_MSG_REQUEST_SUCCESS) { 582 if (rfwd->listen_port == 0) { 583 rfwd->allocated_port = packet_get_int(); 584 logit("Allocated port %u for mux remote forward" 585 " to %s:%d", rfwd->allocated_port, 586 rfwd->connect_host, rfwd->connect_port); 587 buffer_put_int(&out, MUX_S_REMOTE_PORT); 588 buffer_put_int(&out, fctx->rid); 589 buffer_put_int(&out, rfwd->allocated_port); 590 channel_update_permitted_opens(rfwd->handle, 591 rfwd->allocated_port); 592 } else { 593 buffer_put_int(&out, MUX_S_OK); 594 buffer_put_int(&out, fctx->rid); 595 } 596 goto out; 597 } else { 598 if (rfwd->listen_port == 0) 599 channel_update_permitted_opens(rfwd->handle, -1); 600 xasprintf(&failmsg, "remote port forwarding failed for " 601 "listen port %d", rfwd->listen_port); 602 } 603 fail: 604 error("%s: %s", __func__, failmsg); 605 buffer_put_int(&out, MUX_S_FAILURE); 606 buffer_put_int(&out, fctx->rid); 607 buffer_put_cstring(&out, failmsg); 608 free(failmsg); 609 out: 610 buffer_put_string(&c->output, buffer_ptr(&out), buffer_len(&out)); 611 buffer_free(&out); 612 if (c->mux_pause <= 0) 613 fatal("%s: mux_pause %d", __func__, c->mux_pause); 614 c->mux_pause = 0; /* start processing messages again */ 615 } 616 617 static int 618 process_mux_open_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r) 619 { 620 Forward fwd; 621 char *fwd_desc = NULL; 622 u_int ftype; 623 u_int lport, cport; 624 int i, ret = 0, freefwd = 1; 625 626 fwd.listen_host = fwd.connect_host = NULL; 627 if (buffer_get_int_ret(&ftype, m) != 0 || 628 (fwd.listen_host = buffer_get_string_ret(m, NULL)) == NULL || 629 buffer_get_int_ret(&lport, m) != 0 || 630 (fwd.connect_host = buffer_get_string_ret(m, NULL)) == NULL || 631 buffer_get_int_ret(&cport, m) != 0 || 632 lport > 65535 || cport > 65535) { 633 error("%s: malformed message", __func__); 634 ret = -1; 635 goto out; 636 } 637 fwd.listen_port = lport; 638 fwd.connect_port = cport; 639 if (*fwd.listen_host == '\0') { 640 free(fwd.listen_host); 641 fwd.listen_host = NULL; 642 } 643 if (*fwd.connect_host == '\0') { 644 free(fwd.connect_host); 645 fwd.connect_host = NULL; 646 } 647 648 debug2("%s: channel %d: request %s", __func__, c->self, 649 (fwd_desc = format_forward(ftype, &fwd))); 650 651 if (ftype != MUX_FWD_LOCAL && ftype != MUX_FWD_REMOTE && 652 ftype != MUX_FWD_DYNAMIC) { 653 logit("%s: invalid forwarding type %u", __func__, ftype); 654 invalid: 655 free(fwd.listen_host); 656 free(fwd.connect_host); 657 buffer_put_int(r, MUX_S_FAILURE); 658 buffer_put_int(r, rid); 659 buffer_put_cstring(r, "Invalid forwarding request"); 660 return 0; 661 } 662 if (fwd.listen_port >= 65536) { 663 logit("%s: invalid listen port %u", __func__, 664 fwd.listen_port); 665 goto invalid; 666 } 667 if (fwd.connect_port >= 65536 || (ftype != MUX_FWD_DYNAMIC && 668 ftype != MUX_FWD_REMOTE && fwd.connect_port == 0)) { 669 logit("%s: invalid connect port %u", __func__, 670 fwd.connect_port); 671 goto invalid; 672 } 673 if (ftype != MUX_FWD_DYNAMIC && fwd.connect_host == NULL) { 674 logit("%s: missing connect host", __func__); 675 goto invalid; 676 } 677 678 /* Skip forwards that have already been requested */ 679 switch (ftype) { 680 case MUX_FWD_LOCAL: 681 case MUX_FWD_DYNAMIC: 682 for (i = 0; i < options.num_local_forwards; i++) { 683 if (compare_forward(&fwd, 684 options.local_forwards + i)) { 685 exists: 686 debug2("%s: found existing forwarding", 687 __func__); 688 buffer_put_int(r, MUX_S_OK); 689 buffer_put_int(r, rid); 690 goto out; 691 } 692 } 693 break; 694 case MUX_FWD_REMOTE: 695 for (i = 0; i < options.num_remote_forwards; i++) { 696 if (compare_forward(&fwd, 697 options.remote_forwards + i)) { 698 if (fwd.listen_port != 0) 699 goto exists; 700 debug2("%s: found allocated port", 701 __func__); 702 buffer_put_int(r, MUX_S_REMOTE_PORT); 703 buffer_put_int(r, rid); 704 buffer_put_int(r, 705 options.remote_forwards[i].allocated_port); 706 goto out; 707 } 708 } 709 break; 710 } 711 712 if (options.control_master == SSHCTL_MASTER_ASK || 713 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 714 if (!ask_permission("Open %s on %s?", fwd_desc, host)) { 715 debug2("%s: forwarding refused by user", __func__); 716 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 717 buffer_put_int(r, rid); 718 buffer_put_cstring(r, "Permission denied"); 719 goto out; 720 } 721 } 722 723 if (ftype == MUX_FWD_LOCAL || ftype == MUX_FWD_DYNAMIC) { 724 if (!channel_setup_local_fwd_listener(fwd.listen_host, 725 fwd.listen_port, fwd.connect_host, fwd.connect_port, 726 options.gateway_ports)) { 727 fail: 728 logit("slave-requested %s failed", fwd_desc); 729 buffer_put_int(r, MUX_S_FAILURE); 730 buffer_put_int(r, rid); 731 buffer_put_cstring(r, "Port forwarding failed"); 732 goto out; 733 } 734 add_local_forward(&options, &fwd); 735 freefwd = 0; 736 } else { 737 struct mux_channel_confirm_ctx *fctx; 738 739 fwd.handle = channel_request_remote_forwarding(fwd.listen_host, 740 fwd.listen_port, fwd.connect_host, fwd.connect_port); 741 if (fwd.handle < 0) 742 goto fail; 743 add_remote_forward(&options, &fwd); 744 fctx = xcalloc(1, sizeof(*fctx)); 745 fctx->cid = c->self; 746 fctx->rid = rid; 747 fctx->fid = options.num_remote_forwards - 1; 748 client_register_global_confirm(mux_confirm_remote_forward, 749 fctx); 750 freefwd = 0; 751 c->mux_pause = 1; /* wait for mux_confirm_remote_forward */ 752 /* delayed reply in mux_confirm_remote_forward */ 753 goto out; 754 } 755 buffer_put_int(r, MUX_S_OK); 756 buffer_put_int(r, rid); 757 out: 758 free(fwd_desc); 759 if (freefwd) { 760 free(fwd.listen_host); 761 free(fwd.connect_host); 762 } 763 return ret; 764 } 765 766 static int 767 process_mux_close_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r) 768 { 769 Forward fwd, *found_fwd; 770 char *fwd_desc = NULL; 771 const char *error_reason = NULL; 772 u_int ftype; 773 int i, listen_port, ret = 0; 774 u_int lport, cport; 775 776 fwd.listen_host = fwd.connect_host = NULL; 777 if (buffer_get_int_ret(&ftype, m) != 0 || 778 (fwd.listen_host = buffer_get_string_ret(m, NULL)) == NULL || 779 buffer_get_int_ret(&lport, m) != 0 || 780 (fwd.connect_host = buffer_get_string_ret(m, NULL)) == NULL || 781 buffer_get_int_ret(&cport, m) != 0 || 782 lport > 65535 || cport > 65535) { 783 error("%s: malformed message", __func__); 784 ret = -1; 785 goto out; 786 } 787 fwd.listen_port = lport; 788 fwd.connect_port = cport; 789 790 if (*fwd.listen_host == '\0') { 791 free(fwd.listen_host); 792 fwd.listen_host = NULL; 793 } 794 if (*fwd.connect_host == '\0') { 795 free(fwd.connect_host); 796 fwd.connect_host = NULL; 797 } 798 799 debug2("%s: channel %d: request cancel %s", __func__, c->self, 800 (fwd_desc = format_forward(ftype, &fwd))); 801 802 /* make sure this has been requested */ 803 found_fwd = NULL; 804 switch (ftype) { 805 case MUX_FWD_LOCAL: 806 case MUX_FWD_DYNAMIC: 807 for (i = 0; i < options.num_local_forwards; i++) { 808 if (compare_forward(&fwd, 809 options.local_forwards + i)) { 810 found_fwd = options.local_forwards + i; 811 break; 812 } 813 } 814 break; 815 case MUX_FWD_REMOTE: 816 for (i = 0; i < options.num_remote_forwards; i++) { 817 if (compare_forward(&fwd, 818 options.remote_forwards + i)) { 819 found_fwd = options.remote_forwards + i; 820 break; 821 } 822 } 823 break; 824 } 825 826 if (found_fwd == NULL) 827 error_reason = "port not forwarded"; 828 else if (ftype == MUX_FWD_REMOTE) { 829 /* 830 * This shouldn't fail unless we confused the host/port 831 * between options.remote_forwards and permitted_opens. 832 * However, for dynamic allocated listen ports we need 833 * to lookup the actual listen port. 834 */ 835 listen_port = (fwd.listen_port == 0) ? 836 found_fwd->allocated_port : fwd.listen_port; 837 if (channel_request_rforward_cancel(fwd.listen_host, 838 listen_port) == -1) 839 error_reason = "port not in permitted opens"; 840 } else { /* local and dynamic forwards */ 841 /* Ditto */ 842 if (channel_cancel_lport_listener(fwd.listen_host, 843 fwd.listen_port, fwd.connect_port, 844 options.gateway_ports) == -1) 845 error_reason = "port not found"; 846 } 847 848 if (error_reason == NULL) { 849 buffer_put_int(r, MUX_S_OK); 850 buffer_put_int(r, rid); 851 852 free(found_fwd->listen_host); 853 free(found_fwd->connect_host); 854 found_fwd->listen_host = found_fwd->connect_host = NULL; 855 found_fwd->listen_port = found_fwd->connect_port = 0; 856 } else { 857 buffer_put_int(r, MUX_S_FAILURE); 858 buffer_put_int(r, rid); 859 buffer_put_cstring(r, error_reason); 860 } 861 out: 862 free(fwd_desc); 863 free(fwd.listen_host); 864 free(fwd.connect_host); 865 866 return ret; 867 } 868 869 static int 870 process_mux_stdio_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r) 871 { 872 Channel *nc; 873 char *reserved, *chost; 874 u_int cport, i, j; 875 int new_fd[2]; 876 877 chost = reserved = NULL; 878 if ((reserved = buffer_get_string_ret(m, NULL)) == NULL || 879 (chost = buffer_get_string_ret(m, NULL)) == NULL || 880 buffer_get_int_ret(&cport, m) != 0) { 881 free(reserved); 882 free(chost); 883 error("%s: malformed message", __func__); 884 return -1; 885 } 886 free(reserved); 887 888 debug2("%s: channel %d: request stdio fwd to %s:%u", 889 __func__, c->self, chost, cport); 890 891 /* Gather fds from client */ 892 for(i = 0; i < 2; i++) { 893 if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) { 894 error("%s: failed to receive fd %d from slave", 895 __func__, i); 896 for (j = 0; j < i; j++) 897 close(new_fd[j]); 898 free(chost); 899 900 /* prepare reply */ 901 buffer_put_int(r, MUX_S_FAILURE); 902 buffer_put_int(r, rid); 903 buffer_put_cstring(r, 904 "did not receive file descriptors"); 905 return -1; 906 } 907 } 908 909 debug3("%s: got fds stdin %d, stdout %d", __func__, 910 new_fd[0], new_fd[1]); 911 912 /* XXX support multiple child sessions in future */ 913 if (c->remote_id != -1) { 914 debug2("%s: session already open", __func__); 915 /* prepare reply */ 916 buffer_put_int(r, MUX_S_FAILURE); 917 buffer_put_int(r, rid); 918 buffer_put_cstring(r, "Multiple sessions not supported"); 919 cleanup: 920 close(new_fd[0]); 921 close(new_fd[1]); 922 free(chost); 923 return 0; 924 } 925 926 if (options.control_master == SSHCTL_MASTER_ASK || 927 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 928 if (!ask_permission("Allow forward to %s:%u? ", 929 chost, cport)) { 930 debug2("%s: stdio fwd refused by user", __func__); 931 /* prepare reply */ 932 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 933 buffer_put_int(r, rid); 934 buffer_put_cstring(r, "Permission denied"); 935 goto cleanup; 936 } 937 } 938 939 /* enable nonblocking unless tty */ 940 if (!isatty(new_fd[0])) 941 set_nonblock(new_fd[0]); 942 if (!isatty(new_fd[1])) 943 set_nonblock(new_fd[1]); 944 945 nc = channel_connect_stdio_fwd(chost, cport, new_fd[0], new_fd[1]); 946 947 nc->ctl_chan = c->self; /* link session -> control channel */ 948 c->remote_id = nc->self; /* link control -> session channel */ 949 950 debug2("%s: channel_new: %d linked to control channel %d", 951 __func__, nc->self, nc->ctl_chan); 952 953 channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1); 954 955 /* prepare reply */ 956 /* XXX defer until channel confirmed */ 957 buffer_put_int(r, MUX_S_SESSION_OPENED); 958 buffer_put_int(r, rid); 959 buffer_put_int(r, nc->self); 960 961 return 0; 962 } 963 964 static int 965 process_mux_stop_listening(u_int rid, Channel *c, Buffer *m, Buffer *r) 966 { 967 debug("%s: channel %d: stop listening", __func__, c->self); 968 969 if (options.control_master == SSHCTL_MASTER_ASK || 970 options.control_master == SSHCTL_MASTER_AUTO_ASK) { 971 if (!ask_permission("Disable further multiplexing on shared " 972 "connection to %s? ", host)) { 973 debug2("%s: stop listen refused by user", __func__); 974 buffer_put_int(r, MUX_S_PERMISSION_DENIED); 975 buffer_put_int(r, rid); 976 buffer_put_cstring(r, "Permission denied"); 977 return 0; 978 } 979 } 980 981 if (mux_listener_channel != NULL) { 982 channel_free(mux_listener_channel); 983 client_stop_mux(); 984 free(options.control_path); 985 options.control_path = NULL; 986 mux_listener_channel = NULL; 987 muxserver_sock = -1; 988 } 989 990 /* prepare reply */ 991 buffer_put_int(r, MUX_S_OK); 992 buffer_put_int(r, rid); 993 994 return 0; 995 } 996 997 /* Channel callbacks fired on read/write from mux slave fd */ 998 static int 999 mux_master_read_cb(Channel *c) 1000 { 1001 struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx; 1002 Buffer in, out; 1003 void *ptr; 1004 u_int type, rid, have, i; 1005 int ret = -1; 1006 1007 /* Setup ctx and */ 1008 if (c->mux_ctx == NULL) { 1009 state = xcalloc(1, sizeof(*state)); 1010 c->mux_ctx = state; 1011 channel_register_cleanup(c->self, 1012 mux_master_control_cleanup_cb, 0); 1013 1014 /* Send hello */ 1015 buffer_init(&out); 1016 buffer_put_int(&out, MUX_MSG_HELLO); 1017 buffer_put_int(&out, SSHMUX_VER); 1018 /* no extensions */ 1019 buffer_put_string(&c->output, buffer_ptr(&out), 1020 buffer_len(&out)); 1021 buffer_free(&out); 1022 debug3("%s: channel %d: hello sent", __func__, c->self); 1023 return 0; 1024 } 1025 1026 buffer_init(&in); 1027 buffer_init(&out); 1028 1029 /* Channel code ensures that we receive whole packets */ 1030 if ((ptr = buffer_get_string_ptr_ret(&c->input, &have)) == NULL) { 1031 malf: 1032 error("%s: malformed message", __func__); 1033 goto out; 1034 } 1035 buffer_append(&in, ptr, have); 1036 1037 if (buffer_get_int_ret(&type, &in) != 0) 1038 goto malf; 1039 debug3("%s: channel %d packet type 0x%08x len %u", 1040 __func__, c->self, type, buffer_len(&in)); 1041 1042 if (type == MUX_MSG_HELLO) 1043 rid = 0; 1044 else { 1045 if (!state->hello_rcvd) { 1046 error("%s: expected MUX_MSG_HELLO(0x%08x), " 1047 "received 0x%08x", __func__, MUX_MSG_HELLO, type); 1048 goto out; 1049 } 1050 if (buffer_get_int_ret(&rid, &in) != 0) 1051 goto malf; 1052 } 1053 1054 for (i = 0; mux_master_handlers[i].handler != NULL; i++) { 1055 if (type == mux_master_handlers[i].type) { 1056 ret = mux_master_handlers[i].handler(rid, c, &in, &out); 1057 break; 1058 } 1059 } 1060 if (mux_master_handlers[i].handler == NULL) { 1061 error("%s: unsupported mux message 0x%08x", __func__, type); 1062 buffer_put_int(&out, MUX_S_FAILURE); 1063 buffer_put_int(&out, rid); 1064 buffer_put_cstring(&out, "unsupported request"); 1065 ret = 0; 1066 } 1067 /* Enqueue reply packet */ 1068 if (buffer_len(&out) != 0) { 1069 buffer_put_string(&c->output, buffer_ptr(&out), 1070 buffer_len(&out)); 1071 } 1072 out: 1073 buffer_free(&in); 1074 buffer_free(&out); 1075 return ret; 1076 } 1077 1078 void 1079 mux_exit_message(Channel *c, int exitval) 1080 { 1081 Buffer m; 1082 Channel *mux_chan; 1083 1084 debug3("%s: channel %d: exit message, exitval %d", __func__, c->self, 1085 exitval); 1086 1087 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL) 1088 fatal("%s: channel %d missing mux channel %d", 1089 __func__, c->self, c->ctl_chan); 1090 1091 /* Append exit message packet to control socket output queue */ 1092 buffer_init(&m); 1093 buffer_put_int(&m, MUX_S_EXIT_MESSAGE); 1094 buffer_put_int(&m, c->self); 1095 buffer_put_int(&m, exitval); 1096 1097 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m)); 1098 buffer_free(&m); 1099 } 1100 1101 void 1102 mux_tty_alloc_failed(Channel *c) 1103 { 1104 Buffer m; 1105 Channel *mux_chan; 1106 1107 debug3("%s: channel %d: TTY alloc failed", __func__, c->self); 1108 1109 if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL) 1110 fatal("%s: channel %d missing mux channel %d", 1111 __func__, c->self, c->ctl_chan); 1112 1113 /* Append exit message packet to control socket output queue */ 1114 buffer_init(&m); 1115 buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL); 1116 buffer_put_int(&m, c->self); 1117 1118 buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m)); 1119 buffer_free(&m); 1120 } 1121 1122 /* Prepare a mux master to listen on a Unix domain socket. */ 1123 void 1124 muxserver_listen(void) 1125 { 1126 struct sockaddr_un addr; 1127 mode_t old_umask; 1128 char *orig_control_path = options.control_path; 1129 char rbuf[16+1]; 1130 u_int i, r; 1131 1132 if (options.control_path == NULL || 1133 options.control_master == SSHCTL_MASTER_NO) 1134 return; 1135 1136 debug("setting up multiplex master socket"); 1137 1138 /* 1139 * Use a temporary path before listen so we can pseudo-atomically 1140 * establish the listening socket in its final location to avoid 1141 * other processes racing in between bind() and listen() and hitting 1142 * an unready socket. 1143 */ 1144 for (i = 0; i < sizeof(rbuf) - 1; i++) { 1145 r = arc4random_uniform(26+26+10); 1146 rbuf[i] = (r < 26) ? 'a' + r : 1147 (r < 26*2) ? 'A' + r - 26 : 1148 '0' + r - 26 - 26; 1149 } 1150 rbuf[sizeof(rbuf) - 1] = '\0'; 1151 options.control_path = NULL; 1152 xasprintf(&options.control_path, "%s.%s", orig_control_path, rbuf); 1153 debug3("%s: temporary control path %s", __func__, options.control_path); 1154 1155 memset(&addr, '\0', sizeof(addr)); 1156 addr.sun_family = AF_UNIX; 1157 addr.sun_len = offsetof(struct sockaddr_un, sun_path) + 1158 strlen(options.control_path) + 1; 1159 1160 if (strlcpy(addr.sun_path, options.control_path, 1161 sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) { 1162 error("ControlPath \"%s\" too long for Unix domain socket", 1163 options.control_path); 1164 goto disable_mux_master; 1165 } 1166 1167 if ((muxserver_sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) 1168 fatal("%s socket(): %s", __func__, strerror(errno)); 1169 1170 old_umask = umask(0177); 1171 if (bind(muxserver_sock, (struct sockaddr *)&addr, addr.sun_len) == -1) { 1172 if (errno == EINVAL || errno == EADDRINUSE) { 1173 error("ControlSocket %s already exists, " 1174 "disabling multiplexing", options.control_path); 1175 disable_mux_master: 1176 if (muxserver_sock != -1) { 1177 close(muxserver_sock); 1178 muxserver_sock = -1; 1179 } 1180 free(orig_control_path); 1181 free(options.control_path); 1182 options.control_path = NULL; 1183 options.control_master = SSHCTL_MASTER_NO; 1184 return; 1185 } else 1186 fatal("%s bind(): %s", __func__, strerror(errno)); 1187 } 1188 umask(old_umask); 1189 1190 if (listen(muxserver_sock, 64) == -1) 1191 fatal("%s listen(): %s", __func__, strerror(errno)); 1192 1193 /* Now atomically "move" the mux socket into position */ 1194 if (link(options.control_path, orig_control_path) != 0) { 1195 if (errno != EEXIST) { 1196 fatal("%s: link mux listener %s => %s: %s", __func__, 1197 options.control_path, orig_control_path, 1198 strerror(errno)); 1199 } 1200 error("ControlSocket %s already exists, disabling multiplexing", 1201 orig_control_path); 1202 unlink(options.control_path); 1203 goto disable_mux_master; 1204 } 1205 unlink(options.control_path); 1206 free(options.control_path); 1207 options.control_path = orig_control_path; 1208 1209 set_nonblock(muxserver_sock); 1210 1211 mux_listener_channel = channel_new("mux listener", 1212 SSH_CHANNEL_MUX_LISTENER, muxserver_sock, muxserver_sock, -1, 1213 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1214 0, options.control_path, 1); 1215 mux_listener_channel->mux_rcb = mux_master_read_cb; 1216 debug3("%s: mux listener channel %d fd %d", __func__, 1217 mux_listener_channel->self, mux_listener_channel->sock); 1218 } 1219 1220 /* Callback on open confirmation in mux master for a mux client session. */ 1221 static void 1222 mux_session_confirm(int id, int success, void *arg) 1223 { 1224 struct mux_session_confirm_ctx *cctx = arg; 1225 const char *display; 1226 Channel *c, *cc; 1227 int i; 1228 Buffer reply; 1229 1230 if (cctx == NULL) 1231 fatal("%s: cctx == NULL", __func__); 1232 if ((c = channel_by_id(id)) == NULL) 1233 fatal("%s: no channel for id %d", __func__, id); 1234 if ((cc = channel_by_id(c->ctl_chan)) == NULL) 1235 fatal("%s: channel %d lacks control channel %d", __func__, 1236 id, c->ctl_chan); 1237 1238 if (!success) { 1239 debug3("%s: sending failure reply", __func__); 1240 /* prepare reply */ 1241 buffer_init(&reply); 1242 buffer_put_int(&reply, MUX_S_FAILURE); 1243 buffer_put_int(&reply, cctx->rid); 1244 buffer_put_cstring(&reply, "Session open refused by peer"); 1245 goto done; 1246 } 1247 1248 display = getenv("DISPLAY"); 1249 if (cctx->want_x_fwd && options.forward_x11 && display != NULL) { 1250 char *proto, *data; 1251 1252 /* Get reasonable local authentication information. */ 1253 client_x11_get_proto(display, options.xauth_location, 1254 options.forward_x11_trusted, options.forward_x11_timeout, 1255 &proto, &data); 1256 /* Request forwarding with authentication spoofing. */ 1257 debug("Requesting X11 forwarding with authentication " 1258 "spoofing."); 1259 x11_request_forwarding_with_spoofing(id, display, proto, 1260 data, 1); 1261 client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN); 1262 /* XXX exit_on_forward_failure */ 1263 } 1264 1265 if (cctx->want_agent_fwd && options.forward_agent) { 1266 debug("Requesting authentication agent forwarding."); 1267 channel_request_start(id, "auth-agent-req@openssh.com", 0); 1268 packet_send(); 1269 } 1270 1271 client_session2_setup(id, cctx->want_tty, cctx->want_subsys, 1272 cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env); 1273 1274 debug3("%s: sending success reply", __func__); 1275 /* prepare reply */ 1276 buffer_init(&reply); 1277 buffer_put_int(&reply, MUX_S_SESSION_OPENED); 1278 buffer_put_int(&reply, cctx->rid); 1279 buffer_put_int(&reply, c->self); 1280 1281 done: 1282 /* Send reply */ 1283 buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply)); 1284 buffer_free(&reply); 1285 1286 if (cc->mux_pause <= 0) 1287 fatal("%s: mux_pause %d", __func__, cc->mux_pause); 1288 cc->mux_pause = 0; /* start processing messages again */ 1289 c->open_confirm_ctx = NULL; 1290 buffer_free(&cctx->cmd); 1291 free(cctx->term); 1292 if (cctx->env != NULL) { 1293 for (i = 0; cctx->env[i] != NULL; i++) 1294 free(cctx->env[i]); 1295 free(cctx->env); 1296 } 1297 free(cctx); 1298 } 1299 1300 /* ** Multiplexing client support */ 1301 1302 /* Exit signal handler */ 1303 static void 1304 control_client_sighandler(int signo) 1305 { 1306 muxclient_terminate = signo; 1307 } 1308 1309 /* 1310 * Relay signal handler - used to pass some signals from mux client to 1311 * mux master. 1312 */ 1313 static void 1314 control_client_sigrelay(int signo) 1315 { 1316 int save_errno = errno; 1317 1318 if (muxserver_pid > 1) 1319 kill(muxserver_pid, signo); 1320 1321 errno = save_errno; 1322 } 1323 1324 static int 1325 mux_client_read(int fd, Buffer *b, u_int need) 1326 { 1327 u_int have; 1328 ssize_t len; 1329 u_char *p; 1330 struct pollfd pfd; 1331 1332 pfd.fd = fd; 1333 pfd.events = POLLIN; 1334 p = buffer_append_space(b, need); 1335 for (have = 0; have < need; ) { 1336 if (muxclient_terminate) { 1337 errno = EINTR; 1338 return -1; 1339 } 1340 len = read(fd, p + have, need - have); 1341 if (len < 0) { 1342 switch (errno) { 1343 case EAGAIN: 1344 (void)poll(&pfd, 1, -1); 1345 /* FALLTHROUGH */ 1346 case EINTR: 1347 continue; 1348 default: 1349 return -1; 1350 } 1351 } 1352 if (len == 0) { 1353 errno = EPIPE; 1354 return -1; 1355 } 1356 have += (u_int)len; 1357 } 1358 return 0; 1359 } 1360 1361 static int 1362 mux_client_write_packet(int fd, Buffer *m) 1363 { 1364 Buffer queue; 1365 u_int have, need; 1366 int oerrno, len; 1367 u_char *ptr; 1368 struct pollfd pfd; 1369 1370 pfd.fd = fd; 1371 pfd.events = POLLOUT; 1372 buffer_init(&queue); 1373 buffer_put_string(&queue, buffer_ptr(m), buffer_len(m)); 1374 1375 need = buffer_len(&queue); 1376 ptr = buffer_ptr(&queue); 1377 1378 for (have = 0; have < need; ) { 1379 if (muxclient_terminate) { 1380 buffer_free(&queue); 1381 errno = EINTR; 1382 return -1; 1383 } 1384 len = write(fd, ptr + have, need - have); 1385 if (len < 0) { 1386 switch (errno) { 1387 case EAGAIN: 1388 (void)poll(&pfd, 1, -1); 1389 /* FALLTHROUGH */ 1390 case EINTR: 1391 continue; 1392 default: 1393 oerrno = errno; 1394 buffer_free(&queue); 1395 errno = oerrno; 1396 return -1; 1397 } 1398 } 1399 if (len == 0) { 1400 buffer_free(&queue); 1401 errno = EPIPE; 1402 return -1; 1403 } 1404 have += (u_int)len; 1405 } 1406 buffer_free(&queue); 1407 return 0; 1408 } 1409 1410 static int 1411 mux_client_read_packet(int fd, Buffer *m) 1412 { 1413 Buffer queue; 1414 u_int need, have; 1415 void *ptr; 1416 int oerrno; 1417 1418 buffer_init(&queue); 1419 if (mux_client_read(fd, &queue, 4) != 0) { 1420 if ((oerrno = errno) == EPIPE) 1421 debug3("%s: read header failed: %s", __func__, 1422 strerror(errno)); 1423 buffer_free(&queue); 1424 errno = oerrno; 1425 return -1; 1426 } 1427 need = get_u32(buffer_ptr(&queue)); 1428 if (mux_client_read(fd, &queue, need) != 0) { 1429 oerrno = errno; 1430 debug3("%s: read body failed: %s", __func__, strerror(errno)); 1431 buffer_free(&queue); 1432 errno = oerrno; 1433 return -1; 1434 } 1435 ptr = buffer_get_string_ptr(&queue, &have); 1436 buffer_append(m, ptr, have); 1437 buffer_free(&queue); 1438 return 0; 1439 } 1440 1441 static int 1442 mux_client_hello_exchange(int fd) 1443 { 1444 Buffer m; 1445 u_int type, ver; 1446 1447 buffer_init(&m); 1448 buffer_put_int(&m, MUX_MSG_HELLO); 1449 buffer_put_int(&m, SSHMUX_VER); 1450 /* no extensions */ 1451 1452 if (mux_client_write_packet(fd, &m) != 0) 1453 fatal("%s: write packet: %s", __func__, strerror(errno)); 1454 1455 buffer_clear(&m); 1456 1457 /* Read their HELLO */ 1458 if (mux_client_read_packet(fd, &m) != 0) { 1459 buffer_free(&m); 1460 return -1; 1461 } 1462 1463 type = buffer_get_int(&m); 1464 if (type != MUX_MSG_HELLO) 1465 fatal("%s: expected HELLO (%u) received %u", 1466 __func__, MUX_MSG_HELLO, type); 1467 ver = buffer_get_int(&m); 1468 if (ver != SSHMUX_VER) 1469 fatal("Unsupported multiplexing protocol version %d " 1470 "(expected %d)", ver, SSHMUX_VER); 1471 debug2("%s: master version %u", __func__, ver); 1472 /* No extensions are presently defined */ 1473 while (buffer_len(&m) > 0) { 1474 char *name = buffer_get_string(&m, NULL); 1475 char *value = buffer_get_string(&m, NULL); 1476 1477 debug2("Unrecognised master extension \"%s\"", name); 1478 free(name); 1479 free(value); 1480 } 1481 buffer_free(&m); 1482 return 0; 1483 } 1484 1485 static u_int 1486 mux_client_request_alive(int fd) 1487 { 1488 Buffer m; 1489 char *e; 1490 u_int pid, type, rid; 1491 1492 debug3("%s: entering", __func__); 1493 1494 buffer_init(&m); 1495 buffer_put_int(&m, MUX_C_ALIVE_CHECK); 1496 buffer_put_int(&m, muxclient_request_id); 1497 1498 if (mux_client_write_packet(fd, &m) != 0) 1499 fatal("%s: write packet: %s", __func__, strerror(errno)); 1500 1501 buffer_clear(&m); 1502 1503 /* Read their reply */ 1504 if (mux_client_read_packet(fd, &m) != 0) { 1505 buffer_free(&m); 1506 return 0; 1507 } 1508 1509 type = buffer_get_int(&m); 1510 if (type != MUX_S_ALIVE) { 1511 e = buffer_get_string(&m, NULL); 1512 fatal("%s: master returned error: %s", __func__, e); 1513 } 1514 1515 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1516 fatal("%s: out of sequence reply: my id %u theirs %u", 1517 __func__, muxclient_request_id, rid); 1518 pid = buffer_get_int(&m); 1519 buffer_free(&m); 1520 1521 debug3("%s: done pid = %u", __func__, pid); 1522 1523 muxclient_request_id++; 1524 1525 return pid; 1526 } 1527 1528 static void 1529 mux_client_request_terminate(int fd) 1530 { 1531 Buffer m; 1532 char *e; 1533 u_int type, rid; 1534 1535 debug3("%s: entering", __func__); 1536 1537 buffer_init(&m); 1538 buffer_put_int(&m, MUX_C_TERMINATE); 1539 buffer_put_int(&m, muxclient_request_id); 1540 1541 if (mux_client_write_packet(fd, &m) != 0) 1542 fatal("%s: write packet: %s", __func__, strerror(errno)); 1543 1544 buffer_clear(&m); 1545 1546 /* Read their reply */ 1547 if (mux_client_read_packet(fd, &m) != 0) { 1548 /* Remote end exited already */ 1549 if (errno == EPIPE) { 1550 buffer_free(&m); 1551 return; 1552 } 1553 fatal("%s: read from master failed: %s", 1554 __func__, strerror(errno)); 1555 } 1556 1557 type = buffer_get_int(&m); 1558 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1559 fatal("%s: out of sequence reply: my id %u theirs %u", 1560 __func__, muxclient_request_id, rid); 1561 switch (type) { 1562 case MUX_S_OK: 1563 break; 1564 case MUX_S_PERMISSION_DENIED: 1565 e = buffer_get_string(&m, NULL); 1566 fatal("Master refused termination request: %s", e); 1567 case MUX_S_FAILURE: 1568 e = buffer_get_string(&m, NULL); 1569 fatal("%s: termination request failed: %s", __func__, e); 1570 default: 1571 fatal("%s: unexpected response from master 0x%08x", 1572 __func__, type); 1573 } 1574 buffer_free(&m); 1575 muxclient_request_id++; 1576 } 1577 1578 static int 1579 mux_client_forward(int fd, int cancel_flag, u_int ftype, Forward *fwd) 1580 { 1581 Buffer m; 1582 char *e, *fwd_desc; 1583 u_int type, rid; 1584 1585 fwd_desc = format_forward(ftype, fwd); 1586 debug("Requesting %s %s", 1587 cancel_flag ? "cancellation of" : "forwarding of", fwd_desc); 1588 free(fwd_desc); 1589 1590 buffer_init(&m); 1591 buffer_put_int(&m, cancel_flag ? MUX_C_CLOSE_FWD : MUX_C_OPEN_FWD); 1592 buffer_put_int(&m, muxclient_request_id); 1593 buffer_put_int(&m, ftype); 1594 buffer_put_cstring(&m, 1595 fwd->listen_host == NULL ? "" : fwd->listen_host); 1596 buffer_put_int(&m, fwd->listen_port); 1597 buffer_put_cstring(&m, 1598 fwd->connect_host == NULL ? "" : fwd->connect_host); 1599 buffer_put_int(&m, fwd->connect_port); 1600 1601 if (mux_client_write_packet(fd, &m) != 0) 1602 fatal("%s: write packet: %s", __func__, strerror(errno)); 1603 1604 buffer_clear(&m); 1605 1606 /* Read their reply */ 1607 if (mux_client_read_packet(fd, &m) != 0) { 1608 buffer_free(&m); 1609 return -1; 1610 } 1611 1612 type = buffer_get_int(&m); 1613 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1614 fatal("%s: out of sequence reply: my id %u theirs %u", 1615 __func__, muxclient_request_id, rid); 1616 switch (type) { 1617 case MUX_S_OK: 1618 break; 1619 case MUX_S_REMOTE_PORT: 1620 if (cancel_flag) 1621 fatal("%s: got MUX_S_REMOTE_PORT for cancel", __func__); 1622 fwd->allocated_port = buffer_get_int(&m); 1623 logit("Allocated port %u for remote forward to %s:%d", 1624 fwd->allocated_port, 1625 fwd->connect_host ? fwd->connect_host : "", 1626 fwd->connect_port); 1627 if (muxclient_command == SSHMUX_COMMAND_FORWARD) 1628 fprintf(stdout, "%u\n", fwd->allocated_port); 1629 break; 1630 case MUX_S_PERMISSION_DENIED: 1631 e = buffer_get_string(&m, NULL); 1632 buffer_free(&m); 1633 error("Master refused forwarding request: %s", e); 1634 return -1; 1635 case MUX_S_FAILURE: 1636 e = buffer_get_string(&m, NULL); 1637 buffer_free(&m); 1638 error("%s: forwarding request failed: %s", __func__, e); 1639 return -1; 1640 default: 1641 fatal("%s: unexpected response from master 0x%08x", 1642 __func__, type); 1643 } 1644 buffer_free(&m); 1645 1646 muxclient_request_id++; 1647 return 0; 1648 } 1649 1650 static int 1651 mux_client_forwards(int fd, int cancel_flag) 1652 { 1653 int i, ret = 0; 1654 1655 debug3("%s: %s forwardings: %d local, %d remote", __func__, 1656 cancel_flag ? "cancel" : "request", 1657 options.num_local_forwards, options.num_remote_forwards); 1658 1659 /* XXX ExitOnForwardingFailure */ 1660 for (i = 0; i < options.num_local_forwards; i++) { 1661 if (mux_client_forward(fd, cancel_flag, 1662 options.local_forwards[i].connect_port == 0 ? 1663 MUX_FWD_DYNAMIC : MUX_FWD_LOCAL, 1664 options.local_forwards + i) != 0) 1665 ret = -1; 1666 } 1667 for (i = 0; i < options.num_remote_forwards; i++) { 1668 if (mux_client_forward(fd, cancel_flag, MUX_FWD_REMOTE, 1669 options.remote_forwards + i) != 0) 1670 ret = -1; 1671 } 1672 return ret; 1673 } 1674 1675 static int 1676 mux_client_request_session(int fd) 1677 { 1678 Buffer m; 1679 char *e, *term; 1680 u_int i, rid, sid, esid, exitval, type, exitval_seen; 1681 extern char **environ; 1682 int devnull, rawmode; 1683 1684 debug3("%s: entering", __func__); 1685 1686 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) { 1687 error("%s: master alive request failed", __func__); 1688 return -1; 1689 } 1690 1691 signal(SIGPIPE, SIG_IGN); 1692 1693 if (stdin_null_flag) { 1694 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1695 fatal("open(/dev/null): %s", strerror(errno)); 1696 if (dup2(devnull, STDIN_FILENO) == -1) 1697 fatal("dup2: %s", strerror(errno)); 1698 if (devnull > STDERR_FILENO) 1699 close(devnull); 1700 } 1701 1702 term = getenv("TERM"); 1703 1704 buffer_init(&m); 1705 buffer_put_int(&m, MUX_C_NEW_SESSION); 1706 buffer_put_int(&m, muxclient_request_id); 1707 buffer_put_cstring(&m, ""); /* reserved */ 1708 buffer_put_int(&m, tty_flag); 1709 buffer_put_int(&m, options.forward_x11); 1710 buffer_put_int(&m, options.forward_agent); 1711 buffer_put_int(&m, subsystem_flag); 1712 buffer_put_int(&m, options.escape_char == SSH_ESCAPECHAR_NONE ? 1713 0xffffffff : (u_int)options.escape_char); 1714 buffer_put_cstring(&m, term == NULL ? "" : term); 1715 buffer_put_string(&m, buffer_ptr(&command), buffer_len(&command)); 1716 1717 if (options.num_send_env > 0 && environ != NULL) { 1718 /* Pass environment */ 1719 for (i = 0; environ[i] != NULL; i++) { 1720 if (env_permitted(environ[i])) { 1721 buffer_put_cstring(&m, environ[i]); 1722 } 1723 } 1724 } 1725 1726 if (mux_client_write_packet(fd, &m) != 0) 1727 fatal("%s: write packet: %s", __func__, strerror(errno)); 1728 1729 /* Send the stdio file descriptors */ 1730 if (mm_send_fd(fd, STDIN_FILENO) == -1 || 1731 mm_send_fd(fd, STDOUT_FILENO) == -1 || 1732 mm_send_fd(fd, STDERR_FILENO) == -1) 1733 fatal("%s: send fds failed", __func__); 1734 1735 debug3("%s: session request sent", __func__); 1736 1737 /* Read their reply */ 1738 buffer_clear(&m); 1739 if (mux_client_read_packet(fd, &m) != 0) { 1740 error("%s: read from master failed: %s", 1741 __func__, strerror(errno)); 1742 buffer_free(&m); 1743 return -1; 1744 } 1745 1746 type = buffer_get_int(&m); 1747 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1748 fatal("%s: out of sequence reply: my id %u theirs %u", 1749 __func__, muxclient_request_id, rid); 1750 switch (type) { 1751 case MUX_S_SESSION_OPENED: 1752 sid = buffer_get_int(&m); 1753 debug("%s: master session id: %u", __func__, sid); 1754 break; 1755 case MUX_S_PERMISSION_DENIED: 1756 e = buffer_get_string(&m, NULL); 1757 buffer_free(&m); 1758 error("Master refused session request: %s", e); 1759 return -1; 1760 case MUX_S_FAILURE: 1761 e = buffer_get_string(&m, NULL); 1762 buffer_free(&m); 1763 error("%s: session request failed: %s", __func__, e); 1764 return -1; 1765 default: 1766 buffer_free(&m); 1767 error("%s: unexpected response from master 0x%08x", 1768 __func__, type); 1769 return -1; 1770 } 1771 muxclient_request_id++; 1772 1773 signal(SIGHUP, control_client_sighandler); 1774 signal(SIGINT, control_client_sighandler); 1775 signal(SIGTERM, control_client_sighandler); 1776 signal(SIGWINCH, control_client_sigrelay); 1777 1778 rawmode = tty_flag; 1779 if (tty_flag) 1780 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1781 1782 /* 1783 * Stick around until the controlee closes the client_fd. 1784 * Before it does, it is expected to write an exit message. 1785 * This process must read the value and wait for the closure of 1786 * the client_fd; if this one closes early, the multiplex master will 1787 * terminate early too (possibly losing data). 1788 */ 1789 for (exitval = 255, exitval_seen = 0;;) { 1790 buffer_clear(&m); 1791 if (mux_client_read_packet(fd, &m) != 0) 1792 break; 1793 type = buffer_get_int(&m); 1794 switch (type) { 1795 case MUX_S_TTY_ALLOC_FAIL: 1796 if ((esid = buffer_get_int(&m)) != sid) 1797 fatal("%s: tty alloc fail on unknown session: " 1798 "my id %u theirs %u", 1799 __func__, sid, esid); 1800 leave_raw_mode(options.request_tty == 1801 REQUEST_TTY_FORCE); 1802 rawmode = 0; 1803 continue; 1804 case MUX_S_EXIT_MESSAGE: 1805 if ((esid = buffer_get_int(&m)) != sid) 1806 fatal("%s: exit on unknown session: " 1807 "my id %u theirs %u", 1808 __func__, sid, esid); 1809 if (exitval_seen) 1810 fatal("%s: exitval sent twice", __func__); 1811 exitval = buffer_get_int(&m); 1812 exitval_seen = 1; 1813 continue; 1814 default: 1815 e = buffer_get_string(&m, NULL); 1816 fatal("%s: master returned error: %s", __func__, e); 1817 } 1818 } 1819 1820 close(fd); 1821 if (rawmode) 1822 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1823 1824 if (muxclient_terminate) { 1825 debug2("Exiting on signal %ld", (long)muxclient_terminate); 1826 exitval = 255; 1827 } else if (!exitval_seen) { 1828 debug2("Control master terminated unexpectedly"); 1829 exitval = 255; 1830 } else 1831 debug2("Received exit status from master %d", exitval); 1832 1833 if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET) 1834 fprintf(stderr, "Shared connection to %s closed.\r\n", host); 1835 1836 exit(exitval); 1837 } 1838 1839 static int 1840 mux_client_request_stdio_fwd(int fd) 1841 { 1842 Buffer m; 1843 char *e; 1844 u_int type, rid, sid; 1845 int devnull; 1846 1847 debug3("%s: entering", __func__); 1848 1849 if ((muxserver_pid = mux_client_request_alive(fd)) == 0) { 1850 error("%s: master alive request failed", __func__); 1851 return -1; 1852 } 1853 1854 signal(SIGPIPE, SIG_IGN); 1855 1856 if (stdin_null_flag) { 1857 if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1) 1858 fatal("open(/dev/null): %s", strerror(errno)); 1859 if (dup2(devnull, STDIN_FILENO) == -1) 1860 fatal("dup2: %s", strerror(errno)); 1861 if (devnull > STDERR_FILENO) 1862 close(devnull); 1863 } 1864 1865 buffer_init(&m); 1866 buffer_put_int(&m, MUX_C_NEW_STDIO_FWD); 1867 buffer_put_int(&m, muxclient_request_id); 1868 buffer_put_cstring(&m, ""); /* reserved */ 1869 buffer_put_cstring(&m, stdio_forward_host); 1870 buffer_put_int(&m, stdio_forward_port); 1871 1872 if (mux_client_write_packet(fd, &m) != 0) 1873 fatal("%s: write packet: %s", __func__, strerror(errno)); 1874 1875 /* Send the stdio file descriptors */ 1876 if (mm_send_fd(fd, STDIN_FILENO) == -1 || 1877 mm_send_fd(fd, STDOUT_FILENO) == -1) 1878 fatal("%s: send fds failed", __func__); 1879 1880 debug3("%s: stdio forward request sent", __func__); 1881 1882 /* Read their reply */ 1883 buffer_clear(&m); 1884 1885 if (mux_client_read_packet(fd, &m) != 0) { 1886 error("%s: read from master failed: %s", 1887 __func__, strerror(errno)); 1888 buffer_free(&m); 1889 return -1; 1890 } 1891 1892 type = buffer_get_int(&m); 1893 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1894 fatal("%s: out of sequence reply: my id %u theirs %u", 1895 __func__, muxclient_request_id, rid); 1896 switch (type) { 1897 case MUX_S_SESSION_OPENED: 1898 sid = buffer_get_int(&m); 1899 debug("%s: master session id: %u", __func__, sid); 1900 break; 1901 case MUX_S_PERMISSION_DENIED: 1902 e = buffer_get_string(&m, NULL); 1903 buffer_free(&m); 1904 fatal("Master refused stdio forwarding request: %s", e); 1905 case MUX_S_FAILURE: 1906 e = buffer_get_string(&m, NULL); 1907 buffer_free(&m); 1908 fatal("%s: stdio forwarding request failed: %s", __func__, e); 1909 default: 1910 buffer_free(&m); 1911 error("%s: unexpected response from master 0x%08x", 1912 __func__, type); 1913 return -1; 1914 } 1915 muxclient_request_id++; 1916 1917 signal(SIGHUP, control_client_sighandler); 1918 signal(SIGINT, control_client_sighandler); 1919 signal(SIGTERM, control_client_sighandler); 1920 signal(SIGWINCH, control_client_sigrelay); 1921 1922 /* 1923 * Stick around until the controlee closes the client_fd. 1924 */ 1925 buffer_clear(&m); 1926 if (mux_client_read_packet(fd, &m) != 0) { 1927 if (errno == EPIPE || 1928 (errno == EINTR && muxclient_terminate != 0)) 1929 return 0; 1930 fatal("%s: mux_client_read_packet: %s", 1931 __func__, strerror(errno)); 1932 } 1933 fatal("%s: master returned unexpected message %u", __func__, type); 1934 } 1935 1936 static void 1937 mux_client_request_stop_listening(int fd) 1938 { 1939 Buffer m; 1940 char *e; 1941 u_int type, rid; 1942 1943 debug3("%s: entering", __func__); 1944 1945 buffer_init(&m); 1946 buffer_put_int(&m, MUX_C_STOP_LISTENING); 1947 buffer_put_int(&m, muxclient_request_id); 1948 1949 if (mux_client_write_packet(fd, &m) != 0) 1950 fatal("%s: write packet: %s", __func__, strerror(errno)); 1951 1952 buffer_clear(&m); 1953 1954 /* Read their reply */ 1955 if (mux_client_read_packet(fd, &m) != 0) 1956 fatal("%s: read from master failed: %s", 1957 __func__, strerror(errno)); 1958 1959 type = buffer_get_int(&m); 1960 if ((rid = buffer_get_int(&m)) != muxclient_request_id) 1961 fatal("%s: out of sequence reply: my id %u theirs %u", 1962 __func__, muxclient_request_id, rid); 1963 switch (type) { 1964 case MUX_S_OK: 1965 break; 1966 case MUX_S_PERMISSION_DENIED: 1967 e = buffer_get_string(&m, NULL); 1968 fatal("Master refused stop listening request: %s", e); 1969 case MUX_S_FAILURE: 1970 e = buffer_get_string(&m, NULL); 1971 fatal("%s: stop listening request failed: %s", __func__, e); 1972 default: 1973 fatal("%s: unexpected response from master 0x%08x", 1974 __func__, type); 1975 } 1976 buffer_free(&m); 1977 muxclient_request_id++; 1978 } 1979 1980 /* Multiplex client main loop. */ 1981 void 1982 muxclient(const char *path) 1983 { 1984 struct sockaddr_un addr; 1985 int sock; 1986 u_int pid; 1987 1988 if (muxclient_command == 0) { 1989 if (stdio_forward_host != NULL) 1990 muxclient_command = SSHMUX_COMMAND_STDIO_FWD; 1991 else 1992 muxclient_command = SSHMUX_COMMAND_OPEN; 1993 } 1994 1995 switch (options.control_master) { 1996 case SSHCTL_MASTER_AUTO: 1997 case SSHCTL_MASTER_AUTO_ASK: 1998 debug("auto-mux: Trying existing master"); 1999 /* FALLTHROUGH */ 2000 case SSHCTL_MASTER_NO: 2001 break; 2002 default: 2003 return; 2004 } 2005 2006 memset(&addr, '\0', sizeof(addr)); 2007 addr.sun_family = AF_UNIX; 2008 addr.sun_len = offsetof(struct sockaddr_un, sun_path) + 2009 strlen(path) + 1; 2010 2011 if (strlcpy(addr.sun_path, path, 2012 sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) 2013 fatal("ControlPath too long"); 2014 2015 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) 2016 fatal("%s socket(): %s", __func__, strerror(errno)); 2017 2018 if (connect(sock, (struct sockaddr *)&addr, addr.sun_len) == -1) { 2019 switch (muxclient_command) { 2020 case SSHMUX_COMMAND_OPEN: 2021 case SSHMUX_COMMAND_STDIO_FWD: 2022 break; 2023 default: 2024 fatal("Control socket connect(%.100s): %s", path, 2025 strerror(errno)); 2026 } 2027 if (errno == ECONNREFUSED && 2028 options.control_master != SSHCTL_MASTER_NO) { 2029 debug("Stale control socket %.100s, unlinking", path); 2030 unlink(path); 2031 } else if (errno == ENOENT) { 2032 debug("Control socket \"%.100s\" does not exist", path); 2033 } else { 2034 error("Control socket connect(%.100s): %s", path, 2035 strerror(errno)); 2036 } 2037 close(sock); 2038 return; 2039 } 2040 set_nonblock(sock); 2041 2042 if (mux_client_hello_exchange(sock) != 0) { 2043 error("%s: master hello exchange failed", __func__); 2044 close(sock); 2045 return; 2046 } 2047 2048 switch (muxclient_command) { 2049 case SSHMUX_COMMAND_ALIVE_CHECK: 2050 if ((pid = mux_client_request_alive(sock)) == 0) 2051 fatal("%s: master alive check failed", __func__); 2052 fprintf(stderr, "Master running (pid=%d)\r\n", pid); 2053 exit(0); 2054 case SSHMUX_COMMAND_TERMINATE: 2055 mux_client_request_terminate(sock); 2056 fprintf(stderr, "Exit request sent.\r\n"); 2057 exit(0); 2058 case SSHMUX_COMMAND_FORWARD: 2059 if (mux_client_forwards(sock, 0) != 0) 2060 fatal("%s: master forward request failed", __func__); 2061 exit(0); 2062 case SSHMUX_COMMAND_OPEN: 2063 if (mux_client_forwards(sock, 0) != 0) { 2064 error("%s: master forward request failed", __func__); 2065 return; 2066 } 2067 mux_client_request_session(sock); 2068 return; 2069 case SSHMUX_COMMAND_STDIO_FWD: 2070 mux_client_request_stdio_fwd(sock); 2071 exit(0); 2072 case SSHMUX_COMMAND_STOP: 2073 mux_client_request_stop_listening(sock); 2074 fprintf(stderr, "Stop listening request sent.\r\n"); 2075 exit(0); 2076 case SSHMUX_COMMAND_CANCEL_FWD: 2077 if (mux_client_forwards(sock, 1) != 0) 2078 error("%s: master cancel forward request failed", 2079 __func__); 2080 exit(0); 2081 default: 2082 fatal("unrecognised muxclient_command %d", muxclient_command); 2083 } 2084 } 2085