1 /* $OpenBSD: channels.c,v 1.439 2024/07/25 22:40:08 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 #include <sys/ioctl.h> 45 #include <sys/un.h> 46 #include <sys/socket.h> 47 #include <sys/time.h> 48 #include <sys/queue.h> 49 50 #include <netinet/in.h> 51 #include <arpa/inet.h> 52 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <limits.h> 56 #include <netdb.h> 57 #include <poll.h> 58 #include <stdarg.h> 59 #include <stdint.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <termios.h> 64 #include <unistd.h> 65 66 #include "xmalloc.h" 67 #include "ssh.h" 68 #include "ssh2.h" 69 #include "ssherr.h" 70 #include "sshbuf.h" 71 #include "packet.h" 72 #include "log.h" 73 #include "misc.h" 74 #include "channels.h" 75 #include "compat.h" 76 #include "canohost.h" 77 #include "sshkey.h" 78 #include "authfd.h" 79 #include "pathnames.h" 80 #include "match.h" 81 82 /* XXX remove once we're satisfied there's no lurking bugs */ 83 /* #define DEBUG_CHANNEL_POLL 1 */ 84 85 /* -- agent forwarding */ 86 #define NUM_SOCKS 10 87 88 /* -- X11 forwarding */ 89 /* Maximum number of fake X11 displays to try. */ 90 #define MAX_DISPLAYS 1000 91 92 /* Per-channel callback for pre/post IO actions */ 93 typedef void chan_fn(struct ssh *, Channel *c); 94 95 /* 96 * Data structure for storing which hosts are permitted for forward requests. 97 * The local sides of any remote forwards are stored in this array to prevent 98 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 99 * network (which might be behind a firewall). 100 */ 101 /* XXX: streamlocal wants a path instead of host:port */ 102 /* Overload host_to_connect; we could just make this match Forward */ 103 /* XXX - can we use listen_host instead of listen_path? */ 104 struct permission { 105 char *host_to_connect; /* Connect to 'host'. */ 106 int port_to_connect; /* Connect to 'port'. */ 107 char *listen_host; /* Remote side should listen address. */ 108 char *listen_path; /* Remote side should listen path. */ 109 int listen_port; /* Remote side should listen port. */ 110 Channel *downstream; /* Downstream mux*/ 111 }; 112 113 /* 114 * Stores the forwarding permission state for a single direction (local or 115 * remote). 116 */ 117 struct permission_set { 118 /* 119 * List of all local permitted host/port pairs to allow for the 120 * user. 121 */ 122 u_int num_permitted_user; 123 struct permission *permitted_user; 124 125 /* 126 * List of all permitted host/port pairs to allow for the admin. 127 */ 128 u_int num_permitted_admin; 129 struct permission *permitted_admin; 130 131 /* 132 * If this is true, all opens/listens are permitted. This is the 133 * case on the server on which we have to trust the client anyway, 134 * and the user could do anything after logging in. 135 */ 136 int all_permitted; 137 }; 138 139 /* Used to record timeouts per channel type */ 140 struct ssh_channel_timeout { 141 char *type_pattern; 142 int timeout_secs; 143 }; 144 145 /* Master structure for channels state */ 146 struct ssh_channels { 147 /* 148 * Pointer to an array containing all allocated channels. The array 149 * is dynamically extended as needed. 150 */ 151 Channel **channels; 152 153 /* 154 * Size of the channel array. All slots of the array must always be 155 * initialized (at least the type field); unused slots set to NULL 156 */ 157 u_int channels_alloc; 158 159 /* 160 * 'channel_pre*' are called just before IO to add any bits 161 * relevant to channels in the c->io_want bitmasks. 162 * 163 * 'channel_post*': perform any appropriate operations for 164 * channels which have c->io_ready events pending. 165 */ 166 chan_fn **channel_pre; 167 chan_fn **channel_post; 168 169 /* -- tcp forwarding */ 170 struct permission_set local_perms; 171 struct permission_set remote_perms; 172 173 /* -- X11 forwarding */ 174 175 /* Saved X11 local (client) display. */ 176 char *x11_saved_display; 177 178 /* Saved X11 authentication protocol name. */ 179 char *x11_saved_proto; 180 181 /* Saved X11 authentication data. This is the real data. */ 182 char *x11_saved_data; 183 u_int x11_saved_data_len; 184 185 /* Deadline after which all X11 connections are refused */ 186 time_t x11_refuse_time; 187 188 /* 189 * Fake X11 authentication data. This is what the server will be 190 * sending us; we should replace any occurrences of this by the 191 * real data. 192 */ 193 u_char *x11_fake_data; 194 u_int x11_fake_data_len; 195 196 /* AF_UNSPEC or AF_INET or AF_INET6 */ 197 int IPv4or6; 198 199 /* Channel timeouts by type */ 200 struct ssh_channel_timeout *timeouts; 201 size_t ntimeouts; 202 /* Global timeout for all OPEN channels */ 203 int global_deadline; 204 time_t lastused; 205 }; 206 207 /* helper */ 208 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 209 static const char *channel_rfwd_bind_host(const char *listen_host); 210 211 /* non-blocking connect helpers */ 212 static int connect_next(struct channel_connect *); 213 static void channel_connect_ctx_free(struct channel_connect *); 214 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 215 static int rdynamic_connect_finish(struct ssh *, Channel *); 216 217 /* Setup helper */ 218 static void channel_handler_init(struct ssh_channels *sc); 219 220 /* -- channel core */ 221 222 void 223 channel_init_channels(struct ssh *ssh) 224 { 225 struct ssh_channels *sc; 226 227 if ((sc = calloc(1, sizeof(*sc))) == NULL) 228 fatal_f("allocation failed"); 229 sc->channels_alloc = 10; 230 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 231 sc->IPv4or6 = AF_UNSPEC; 232 channel_handler_init(sc); 233 234 ssh->chanctxt = sc; 235 } 236 237 Channel * 238 channel_by_id(struct ssh *ssh, int id) 239 { 240 Channel *c; 241 242 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 243 logit_f("%d: bad id", id); 244 return NULL; 245 } 246 c = ssh->chanctxt->channels[id]; 247 if (c == NULL) { 248 logit_f("%d: bad id: channel free", id); 249 return NULL; 250 } 251 return c; 252 } 253 254 Channel * 255 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 256 { 257 Channel *c; 258 u_int i; 259 260 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 261 c = ssh->chanctxt->channels[i]; 262 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 263 return c; 264 } 265 return NULL; 266 } 267 268 /* 269 * Returns the channel if it is allowed to receive protocol messages. 270 * Private channels, like listening sockets, may not receive messages. 271 */ 272 Channel * 273 channel_lookup(struct ssh *ssh, int id) 274 { 275 Channel *c; 276 277 if ((c = channel_by_id(ssh, id)) == NULL) 278 return NULL; 279 280 switch (c->type) { 281 case SSH_CHANNEL_X11_OPEN: 282 case SSH_CHANNEL_LARVAL: 283 case SSH_CHANNEL_CONNECTING: 284 case SSH_CHANNEL_DYNAMIC: 285 case SSH_CHANNEL_RDYNAMIC_OPEN: 286 case SSH_CHANNEL_RDYNAMIC_FINISH: 287 case SSH_CHANNEL_OPENING: 288 case SSH_CHANNEL_OPEN: 289 case SSH_CHANNEL_ABANDONED: 290 case SSH_CHANNEL_MUX_PROXY: 291 return c; 292 } 293 logit("Non-public channel %d, type %d.", id, c->type); 294 return NULL; 295 } 296 297 /* 298 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 299 * match type_pattern. 300 */ 301 void 302 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 303 int timeout_secs) 304 { 305 struct ssh_channels *sc = ssh->chanctxt; 306 307 if (strcmp(type_pattern, "global") == 0) { 308 debug2_f("global channel timeout %d seconds", timeout_secs); 309 sc->global_deadline = timeout_secs; 310 return; 311 } 312 debug2_f("channel type \"%s\" timeout %d seconds", 313 type_pattern, timeout_secs); 314 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 315 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 316 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 317 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 318 sc->ntimeouts++; 319 } 320 321 /* Clears all previously-added channel timeouts */ 322 void 323 channel_clear_timeouts(struct ssh *ssh) 324 { 325 struct ssh_channels *sc = ssh->chanctxt; 326 size_t i; 327 328 debug3_f("clearing"); 329 for (i = 0; i < sc->ntimeouts; i++) 330 free(sc->timeouts[i].type_pattern); 331 free(sc->timeouts); 332 sc->timeouts = NULL; 333 sc->ntimeouts = 0; 334 } 335 336 static int 337 lookup_timeout(struct ssh *ssh, const char *type) 338 { 339 struct ssh_channels *sc = ssh->chanctxt; 340 size_t i; 341 342 for (i = 0; i < sc->ntimeouts; i++) { 343 if (match_pattern(type, sc->timeouts[i].type_pattern)) 344 return sc->timeouts[i].timeout_secs; 345 } 346 347 return 0; 348 } 349 350 /* 351 * Sets "extended type" of a channel; used by session layer to add additional 352 * information about channel types (e.g. shell, login, subsystem) that can then 353 * be used to select timeouts. 354 * Will reset c->inactive_deadline as a side-effect. 355 */ 356 void 357 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 358 { 359 Channel *c; 360 361 if ((c = channel_by_id(ssh, id)) == NULL) 362 fatal_f("missing channel %d", id); 363 if (c->xctype != NULL) 364 free(c->xctype); 365 c->xctype = xstrdup(xctype); 366 /* Type has changed, so look up inactivity deadline again */ 367 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 368 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 369 c->inactive_deadline); 370 } 371 372 /* 373 * update "last used" time on a channel. 374 * NB. nothing else should update lastused except to clear it. 375 */ 376 static void 377 channel_set_used_time(struct ssh *ssh, Channel *c) 378 { 379 ssh->chanctxt->lastused = monotime(); 380 if (c != NULL) 381 c->lastused = ssh->chanctxt->lastused; 382 } 383 384 /* 385 * Get the time at which a channel is due to time out for inactivity. 386 * Returns 0 if the channel is not due to time out ever. 387 */ 388 static time_t 389 channel_get_expiry(struct ssh *ssh, Channel *c) 390 { 391 struct ssh_channels *sc = ssh->chanctxt; 392 time_t expiry = 0, channel_expiry; 393 394 if (sc->lastused != 0 && sc->global_deadline != 0) 395 expiry = sc->lastused + sc->global_deadline; 396 if (c->lastused != 0 && c->inactive_deadline != 0) { 397 channel_expiry = c->lastused + c->inactive_deadline; 398 if (expiry == 0 || channel_expiry < expiry) 399 expiry = channel_expiry; 400 } 401 return expiry; 402 } 403 404 /* 405 * Register filedescriptors for a channel, used when allocating a channel or 406 * when the channel consumer/producer is ready, e.g. shell exec'd 407 */ 408 static void 409 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 410 int extusage, int nonblock, int is_tty) 411 { 412 int val; 413 414 if (rfd != -1) 415 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 416 if (wfd != -1 && wfd != rfd) 417 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 418 if (efd != -1 && efd != rfd && efd != wfd) 419 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 420 421 c->rfd = rfd; 422 c->wfd = wfd; 423 c->sock = (rfd == wfd) ? rfd : -1; 424 c->efd = efd; 425 c->extended_usage = extusage; 426 427 if ((c->isatty = is_tty) != 0) 428 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 429 430 /* enable nonblocking mode */ 431 c->restore_block = 0; 432 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 433 /* 434 * Special handling for stdio file descriptors: do not set 435 * non-blocking mode if they are TTYs. Otherwise prepare to 436 * restore their blocking state on exit to avoid interfering 437 * with other programs that follow. 438 */ 439 if (rfd != -1 && !isatty(rfd) && 440 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 441 c->restore_flags[0] = val; 442 c->restore_block |= CHANNEL_RESTORE_RFD; 443 set_nonblock(rfd); 444 } 445 if (wfd != -1 && !isatty(wfd) && 446 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 447 c->restore_flags[1] = val; 448 c->restore_block |= CHANNEL_RESTORE_WFD; 449 set_nonblock(wfd); 450 } 451 if (efd != -1 && !isatty(efd) && 452 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 453 c->restore_flags[2] = val; 454 c->restore_block |= CHANNEL_RESTORE_EFD; 455 set_nonblock(efd); 456 } 457 } else if (nonblock) { 458 if (rfd != -1) 459 set_nonblock(rfd); 460 if (wfd != -1) 461 set_nonblock(wfd); 462 if (efd != -1) 463 set_nonblock(efd); 464 } 465 /* channel might be entering a larval state, so reset global timeout */ 466 channel_set_used_time(ssh, NULL); 467 } 468 469 /* 470 * Allocate a new channel object and set its type and socket. 471 */ 472 Channel * 473 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 474 u_int window, u_int maxpack, int extusage, const char *remote_name, 475 int nonblock) 476 { 477 struct ssh_channels *sc = ssh->chanctxt; 478 u_int i, found; 479 Channel *c; 480 int r; 481 482 /* Try to find a free slot where to put the new channel. */ 483 for (i = 0; i < sc->channels_alloc; i++) { 484 if (sc->channels[i] == NULL) { 485 /* Found a free slot. */ 486 found = i; 487 break; 488 } 489 } 490 if (i >= sc->channels_alloc) { 491 /* 492 * There are no free slots. Take last+1 slot and expand 493 * the array. 494 */ 495 found = sc->channels_alloc; 496 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 497 fatal_f("internal error: channels_alloc %d too big", 498 sc->channels_alloc); 499 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 500 sc->channels_alloc + 10, sizeof(*sc->channels)); 501 sc->channels_alloc += 10; 502 debug2("channel: expanding %d", sc->channels_alloc); 503 } 504 /* Initialize and return new channel. */ 505 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 506 if ((c->input = sshbuf_new()) == NULL || 507 (c->output = sshbuf_new()) == NULL || 508 (c->extended = sshbuf_new()) == NULL) 509 fatal_f("sshbuf_new failed"); 510 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 511 fatal_fr(r, "sshbuf_set_max_size"); 512 c->ostate = CHAN_OUTPUT_OPEN; 513 c->istate = CHAN_INPUT_OPEN; 514 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 515 c->self = found; 516 c->type = type; 517 c->ctype = ctype; 518 c->local_window = window; 519 c->local_window_max = window; 520 c->local_maxpacket = maxpack; 521 c->remote_name = xstrdup(remote_name); 522 c->ctl_chan = -1; 523 c->delayed = 1; /* prevent call to channel_post handler */ 524 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 525 TAILQ_INIT(&c->status_confirms); 526 debug("channel %d: new %s [%s] (inactive timeout: %u)", 527 found, c->ctype, remote_name, c->inactive_deadline); 528 return c; 529 } 530 531 int 532 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 533 { 534 int ret, fd = *fdp; 535 536 if (fd == -1) 537 return 0; 538 539 /* restore blocking */ 540 if (*fdp == c->rfd && 541 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 542 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 543 else if (*fdp == c->wfd && 544 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 545 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 546 else if (*fdp == c->efd && 547 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 548 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 549 550 if (*fdp == c->rfd) { 551 c->io_want &= ~SSH_CHAN_IO_RFD; 552 c->io_ready &= ~SSH_CHAN_IO_RFD; 553 c->rfd = -1; 554 c->pfds[0] = -1; 555 } 556 if (*fdp == c->wfd) { 557 c->io_want &= ~SSH_CHAN_IO_WFD; 558 c->io_ready &= ~SSH_CHAN_IO_WFD; 559 c->wfd = -1; 560 c->pfds[1] = -1; 561 } 562 if (*fdp == c->efd) { 563 c->io_want &= ~SSH_CHAN_IO_EFD; 564 c->io_ready &= ~SSH_CHAN_IO_EFD; 565 c->efd = -1; 566 c->pfds[2] = -1; 567 } 568 if (*fdp == c->sock) { 569 c->io_want &= ~SSH_CHAN_IO_SOCK; 570 c->io_ready &= ~SSH_CHAN_IO_SOCK; 571 c->sock = -1; 572 c->pfds[3] = -1; 573 } 574 575 ret = close(fd); 576 *fdp = -1; /* probably redundant */ 577 return ret; 578 } 579 580 /* Close all channel fd/socket. */ 581 static void 582 channel_close_fds(struct ssh *ssh, Channel *c) 583 { 584 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 585 586 channel_close_fd(ssh, c, &c->sock); 587 if (rfd != sock) 588 channel_close_fd(ssh, c, &c->rfd); 589 if (wfd != sock && wfd != rfd) 590 channel_close_fd(ssh, c, &c->wfd); 591 if (efd != sock && efd != rfd && efd != wfd) 592 channel_close_fd(ssh, c, &c->efd); 593 } 594 595 static void 596 fwd_perm_clear(struct permission *perm) 597 { 598 free(perm->host_to_connect); 599 free(perm->listen_host); 600 free(perm->listen_path); 601 memset(perm, 0, sizeof(*perm)); 602 } 603 604 /* Returns an printable name for the specified forwarding permission list */ 605 static const char * 606 fwd_ident(int who, int where) 607 { 608 if (who == FORWARD_ADM) { 609 if (where == FORWARD_LOCAL) 610 return "admin local"; 611 else if (where == FORWARD_REMOTE) 612 return "admin remote"; 613 } else if (who == FORWARD_USER) { 614 if (where == FORWARD_LOCAL) 615 return "user local"; 616 else if (where == FORWARD_REMOTE) 617 return "user remote"; 618 } 619 fatal("Unknown forward permission list %d/%d", who, where); 620 } 621 622 /* Returns the forwarding permission list for the specified direction */ 623 static struct permission_set * 624 permission_set_get(struct ssh *ssh, int where) 625 { 626 struct ssh_channels *sc = ssh->chanctxt; 627 628 switch (where) { 629 case FORWARD_LOCAL: 630 return &sc->local_perms; 631 break; 632 case FORWARD_REMOTE: 633 return &sc->remote_perms; 634 break; 635 default: 636 fatal_f("invalid forwarding direction %d", where); 637 } 638 } 639 640 /* Returns pointers to the specified forwarding list and its element count */ 641 static void 642 permission_set_get_array(struct ssh *ssh, int who, int where, 643 struct permission ***permpp, u_int **npermpp) 644 { 645 struct permission_set *pset = permission_set_get(ssh, where); 646 647 switch (who) { 648 case FORWARD_USER: 649 *permpp = &pset->permitted_user; 650 *npermpp = &pset->num_permitted_user; 651 break; 652 case FORWARD_ADM: 653 *permpp = &pset->permitted_admin; 654 *npermpp = &pset->num_permitted_admin; 655 break; 656 default: 657 fatal_f("invalid forwarding client %d", who); 658 } 659 } 660 661 /* Adds an entry to the specified forwarding list */ 662 static int 663 permission_set_add(struct ssh *ssh, int who, int where, 664 const char *host_to_connect, int port_to_connect, 665 const char *listen_host, const char *listen_path, int listen_port, 666 Channel *downstream) 667 { 668 struct permission **permp; 669 u_int n, *npermp; 670 671 permission_set_get_array(ssh, who, where, &permp, &npermp); 672 673 if (*npermp >= INT_MAX) 674 fatal_f("%s overflow", fwd_ident(who, where)); 675 676 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 677 n = (*npermp)++; 678 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 679 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 680 (*permp)[n].port_to_connect = port_to_connect; 681 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 682 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 683 (*permp)[n].listen_port = listen_port; 684 (*permp)[n].downstream = downstream; 685 #undef MAYBE_DUP 686 return (int)n; 687 } 688 689 static void 690 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 691 { 692 struct ssh_channels *sc = ssh->chanctxt; 693 struct permission_set *pset = &sc->local_perms; 694 struct permission *perm; 695 int r; 696 u_int i; 697 698 for (i = 0; i < pset->num_permitted_user; i++) { 699 perm = &pset->permitted_user[i]; 700 if (perm->downstream != c) 701 continue; 702 703 /* cancel on the server, since mux client is gone */ 704 debug("channel %d: cleanup remote forward for %s:%u", 705 c->self, perm->listen_host, perm->listen_port); 706 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 707 (r = sshpkt_put_cstring(ssh, 708 "cancel-tcpip-forward")) != 0 || 709 (r = sshpkt_put_u8(ssh, 0)) != 0 || 710 (r = sshpkt_put_cstring(ssh, 711 channel_rfwd_bind_host(perm->listen_host))) != 0 || 712 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 713 (r = sshpkt_send(ssh)) != 0) { 714 fatal_fr(r, "channel %i", c->self); 715 } 716 fwd_perm_clear(perm); /* unregister */ 717 } 718 } 719 720 /* Free the channel and close its fd/socket. */ 721 void 722 channel_free(struct ssh *ssh, Channel *c) 723 { 724 struct ssh_channels *sc = ssh->chanctxt; 725 char *s; 726 u_int i, n; 727 Channel *other; 728 struct channel_confirm *cc; 729 730 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 731 if ((other = sc->channels[i]) == NULL) 732 continue; 733 n++; 734 /* detach from mux client and prepare for closing */ 735 if (c->type == SSH_CHANNEL_MUX_CLIENT && 736 other->type == SSH_CHANNEL_MUX_PROXY && 737 other->mux_ctx == c) { 738 other->mux_ctx = NULL; 739 other->type = SSH_CHANNEL_OPEN; 740 other->istate = CHAN_INPUT_CLOSED; 741 other->ostate = CHAN_OUTPUT_CLOSED; 742 } 743 } 744 debug("channel %d: free: %s, nchannels %u", c->self, 745 c->remote_name ? c->remote_name : "???", n); 746 747 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 748 mux_remove_remote_forwardings(ssh, c); 749 free(c->mux_ctx); 750 c->mux_ctx = NULL; 751 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 752 free(c->mux_ctx); 753 c->mux_ctx = NULL; 754 } 755 756 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 757 s = channel_open_message(ssh); 758 debug3("channel %d: status: %s", c->self, s); 759 free(s); 760 } 761 762 channel_close_fds(ssh, c); 763 sshbuf_free(c->input); 764 sshbuf_free(c->output); 765 sshbuf_free(c->extended); 766 c->input = c->output = c->extended = NULL; 767 free(c->remote_name); 768 c->remote_name = NULL; 769 free(c->path); 770 c->path = NULL; 771 free(c->listening_addr); 772 c->listening_addr = NULL; 773 free(c->xctype); 774 c->xctype = NULL; 775 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 776 if (cc->abandon_cb != NULL) 777 cc->abandon_cb(ssh, c, cc->ctx); 778 TAILQ_REMOVE(&c->status_confirms, cc, entry); 779 freezero(cc, sizeof(*cc)); 780 } 781 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 782 c->filter_cleanup(ssh, c->self, c->filter_ctx); 783 sc->channels[c->self] = NULL; 784 freezero(c, sizeof(*c)); 785 } 786 787 void 788 channel_free_all(struct ssh *ssh) 789 { 790 u_int i; 791 struct ssh_channels *sc = ssh->chanctxt; 792 793 for (i = 0; i < sc->channels_alloc; i++) 794 if (sc->channels[i] != NULL) 795 channel_free(ssh, sc->channels[i]); 796 797 free(sc->channels); 798 sc->channels = NULL; 799 sc->channels_alloc = 0; 800 801 free(sc->x11_saved_display); 802 sc->x11_saved_display = NULL; 803 804 free(sc->x11_saved_proto); 805 sc->x11_saved_proto = NULL; 806 807 free(sc->x11_saved_data); 808 sc->x11_saved_data = NULL; 809 sc->x11_saved_data_len = 0; 810 811 free(sc->x11_fake_data); 812 sc->x11_fake_data = NULL; 813 sc->x11_fake_data_len = 0; 814 } 815 816 /* 817 * Closes the sockets/fds of all channels. This is used to close extra file 818 * descriptors after a fork. 819 */ 820 void 821 channel_close_all(struct ssh *ssh) 822 { 823 u_int i; 824 825 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 826 if (ssh->chanctxt->channels[i] != NULL) 827 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 828 } 829 830 /* 831 * Stop listening to channels. 832 */ 833 void 834 channel_stop_listening(struct ssh *ssh) 835 { 836 u_int i; 837 Channel *c; 838 839 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 840 c = ssh->chanctxt->channels[i]; 841 if (c != NULL) { 842 switch (c->type) { 843 case SSH_CHANNEL_AUTH_SOCKET: 844 case SSH_CHANNEL_PORT_LISTENER: 845 case SSH_CHANNEL_RPORT_LISTENER: 846 case SSH_CHANNEL_X11_LISTENER: 847 case SSH_CHANNEL_UNIX_LISTENER: 848 case SSH_CHANNEL_RUNIX_LISTENER: 849 channel_close_fd(ssh, c, &c->sock); 850 channel_free(ssh, c); 851 break; 852 } 853 } 854 } 855 } 856 857 /* 858 * Returns true if no channel has too much buffered data, and false if one or 859 * more channel is overfull. 860 */ 861 int 862 channel_not_very_much_buffered_data(struct ssh *ssh) 863 { 864 u_int i; 865 u_int maxsize = ssh_packet_get_maxsize(ssh); 866 Channel *c; 867 868 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 869 c = ssh->chanctxt->channels[i]; 870 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 871 continue; 872 if (sshbuf_len(c->output) > maxsize) { 873 debug2("channel %d: big output buffer %zu > %u", 874 c->self, sshbuf_len(c->output), maxsize); 875 return 0; 876 } 877 } 878 return 1; 879 } 880 881 /* Returns true if any channel is still open. */ 882 int 883 channel_still_open(struct ssh *ssh) 884 { 885 u_int i; 886 Channel *c; 887 888 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 889 c = ssh->chanctxt->channels[i]; 890 if (c == NULL) 891 continue; 892 switch (c->type) { 893 case SSH_CHANNEL_X11_LISTENER: 894 case SSH_CHANNEL_PORT_LISTENER: 895 case SSH_CHANNEL_RPORT_LISTENER: 896 case SSH_CHANNEL_MUX_LISTENER: 897 case SSH_CHANNEL_CLOSED: 898 case SSH_CHANNEL_AUTH_SOCKET: 899 case SSH_CHANNEL_DYNAMIC: 900 case SSH_CHANNEL_RDYNAMIC_OPEN: 901 case SSH_CHANNEL_CONNECTING: 902 case SSH_CHANNEL_ZOMBIE: 903 case SSH_CHANNEL_ABANDONED: 904 case SSH_CHANNEL_UNIX_LISTENER: 905 case SSH_CHANNEL_RUNIX_LISTENER: 906 continue; 907 case SSH_CHANNEL_LARVAL: 908 continue; 909 case SSH_CHANNEL_OPENING: 910 case SSH_CHANNEL_OPEN: 911 case SSH_CHANNEL_RDYNAMIC_FINISH: 912 case SSH_CHANNEL_X11_OPEN: 913 case SSH_CHANNEL_MUX_CLIENT: 914 case SSH_CHANNEL_MUX_PROXY: 915 return 1; 916 default: 917 fatal_f("bad channel type %d", c->type); 918 /* NOTREACHED */ 919 } 920 } 921 return 0; 922 } 923 924 /* Returns true if a channel with a TTY is open. */ 925 int 926 channel_tty_open(struct ssh *ssh) 927 { 928 u_int i; 929 Channel *c; 930 931 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 932 c = ssh->chanctxt->channels[i]; 933 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 934 continue; 935 if (c->client_tty) 936 return 1; 937 } 938 return 0; 939 } 940 941 /* Returns the id of an open channel suitable for keepaliving */ 942 int 943 channel_find_open(struct ssh *ssh) 944 { 945 u_int i; 946 Channel *c; 947 948 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 949 c = ssh->chanctxt->channels[i]; 950 if (c == NULL || !c->have_remote_id) 951 continue; 952 switch (c->type) { 953 case SSH_CHANNEL_CLOSED: 954 case SSH_CHANNEL_DYNAMIC: 955 case SSH_CHANNEL_RDYNAMIC_OPEN: 956 case SSH_CHANNEL_RDYNAMIC_FINISH: 957 case SSH_CHANNEL_X11_LISTENER: 958 case SSH_CHANNEL_PORT_LISTENER: 959 case SSH_CHANNEL_RPORT_LISTENER: 960 case SSH_CHANNEL_MUX_LISTENER: 961 case SSH_CHANNEL_MUX_CLIENT: 962 case SSH_CHANNEL_MUX_PROXY: 963 case SSH_CHANNEL_OPENING: 964 case SSH_CHANNEL_CONNECTING: 965 case SSH_CHANNEL_ZOMBIE: 966 case SSH_CHANNEL_ABANDONED: 967 case SSH_CHANNEL_UNIX_LISTENER: 968 case SSH_CHANNEL_RUNIX_LISTENER: 969 continue; 970 case SSH_CHANNEL_LARVAL: 971 case SSH_CHANNEL_AUTH_SOCKET: 972 case SSH_CHANNEL_OPEN: 973 case SSH_CHANNEL_X11_OPEN: 974 return i; 975 default: 976 fatal_f("bad channel type %d", c->type); 977 /* NOTREACHED */ 978 } 979 } 980 return -1; 981 } 982 983 /* Returns the state of the channel's extended usage flag */ 984 const char * 985 channel_format_extended_usage(const Channel *c) 986 { 987 if (c->efd == -1) 988 return "closed"; 989 990 switch (c->extended_usage) { 991 case CHAN_EXTENDED_WRITE: 992 return "write"; 993 case CHAN_EXTENDED_READ: 994 return "read"; 995 case CHAN_EXTENDED_IGNORE: 996 return "ignore"; 997 default: 998 return "UNKNOWN"; 999 } 1000 } 1001 1002 static char * 1003 channel_format_status(const Channel *c) 1004 { 1005 char *ret = NULL; 1006 1007 xasprintf(&ret, "t%d [%s] %s%u %s%u i%u/%zu o%u/%zu e[%s]/%zu " 1008 "fd %d/%d/%d sock %d cc %d %s%u io 0x%02x/0x%02x", 1009 c->type, c->xctype != NULL ? c->xctype : c->ctype, 1010 c->have_remote_id ? "r" : "nr", c->remote_id, 1011 c->mux_ctx != NULL ? "m" : "nm", c->mux_downstream_id, 1012 c->istate, sshbuf_len(c->input), 1013 c->ostate, sshbuf_len(c->output), 1014 channel_format_extended_usage(c), sshbuf_len(c->extended), 1015 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 1016 c->have_ctl_child_id ? "c" : "nc", c->ctl_child_id, 1017 c->io_want, c->io_ready); 1018 return ret; 1019 } 1020 1021 /* 1022 * Returns a message describing the currently open forwarded connections, 1023 * suitable for sending to the client. The message contains crlf pairs for 1024 * newlines. 1025 */ 1026 char * 1027 channel_open_message(struct ssh *ssh) 1028 { 1029 struct sshbuf *buf; 1030 Channel *c; 1031 u_int i; 1032 int r; 1033 char *cp, *ret; 1034 1035 if ((buf = sshbuf_new()) == NULL) 1036 fatal_f("sshbuf_new"); 1037 if ((r = sshbuf_putf(buf, 1038 "The following connections are open:\r\n")) != 0) 1039 fatal_fr(r, "sshbuf_putf"); 1040 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1041 c = ssh->chanctxt->channels[i]; 1042 if (c == NULL) 1043 continue; 1044 switch (c->type) { 1045 case SSH_CHANNEL_X11_LISTENER: 1046 case SSH_CHANNEL_PORT_LISTENER: 1047 case SSH_CHANNEL_RPORT_LISTENER: 1048 case SSH_CHANNEL_CLOSED: 1049 case SSH_CHANNEL_AUTH_SOCKET: 1050 case SSH_CHANNEL_ZOMBIE: 1051 case SSH_CHANNEL_ABANDONED: 1052 case SSH_CHANNEL_MUX_LISTENER: 1053 case SSH_CHANNEL_UNIX_LISTENER: 1054 case SSH_CHANNEL_RUNIX_LISTENER: 1055 continue; 1056 case SSH_CHANNEL_LARVAL: 1057 case SSH_CHANNEL_OPENING: 1058 case SSH_CHANNEL_CONNECTING: 1059 case SSH_CHANNEL_DYNAMIC: 1060 case SSH_CHANNEL_RDYNAMIC_OPEN: 1061 case SSH_CHANNEL_RDYNAMIC_FINISH: 1062 case SSH_CHANNEL_OPEN: 1063 case SSH_CHANNEL_X11_OPEN: 1064 case SSH_CHANNEL_MUX_PROXY: 1065 case SSH_CHANNEL_MUX_CLIENT: 1066 cp = channel_format_status(c); 1067 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1068 c->self, c->remote_name, cp)) != 0) { 1069 free(cp); 1070 fatal_fr(r, "sshbuf_putf"); 1071 } 1072 free(cp); 1073 continue; 1074 default: 1075 fatal_f("bad channel type %d", c->type); 1076 /* NOTREACHED */ 1077 } 1078 } 1079 if ((ret = sshbuf_dup_string(buf)) == NULL) 1080 fatal_f("sshbuf_dup_string"); 1081 sshbuf_free(buf); 1082 return ret; 1083 } 1084 1085 static void 1086 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1087 { 1088 int r; 1089 1090 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1091 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1092 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1093 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1094 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1095 fatal_r(r, "%s: channel %i: open", where, c->self); 1096 } 1097 } 1098 1099 void 1100 channel_send_open(struct ssh *ssh, int id) 1101 { 1102 Channel *c = channel_lookup(ssh, id); 1103 int r; 1104 1105 if (c == NULL) { 1106 logit("channel_send_open: %d: bad id", id); 1107 return; 1108 } 1109 debug2("channel %d: send open", id); 1110 open_preamble(ssh, __func__, c, c->ctype); 1111 if ((r = sshpkt_send(ssh)) != 0) 1112 fatal_fr(r, "channel %i", c->self); 1113 } 1114 1115 void 1116 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 1117 { 1118 Channel *c = channel_lookup(ssh, id); 1119 int r; 1120 1121 if (c == NULL) { 1122 logit_f("%d: unknown channel id", id); 1123 return; 1124 } 1125 if (!c->have_remote_id) 1126 fatal_f("channel %d: no remote id", c->self); 1127 1128 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1129 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1130 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1131 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1132 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1133 fatal_fr(r, "channel %i", c->self); 1134 } 1135 } 1136 1137 void 1138 channel_register_status_confirm(struct ssh *ssh, int id, 1139 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1140 { 1141 struct channel_confirm *cc; 1142 Channel *c; 1143 1144 if ((c = channel_lookup(ssh, id)) == NULL) 1145 fatal_f("%d: bad id", id); 1146 1147 cc = xcalloc(1, sizeof(*cc)); 1148 cc->cb = cb; 1149 cc->abandon_cb = abandon_cb; 1150 cc->ctx = ctx; 1151 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1152 } 1153 1154 void 1155 channel_register_open_confirm(struct ssh *ssh, int id, 1156 channel_open_fn *fn, void *ctx) 1157 { 1158 Channel *c = channel_lookup(ssh, id); 1159 1160 if (c == NULL) { 1161 logit_f("%d: bad id", id); 1162 return; 1163 } 1164 c->open_confirm = fn; 1165 c->open_confirm_ctx = ctx; 1166 } 1167 1168 void 1169 channel_register_cleanup(struct ssh *ssh, int id, 1170 channel_callback_fn *fn, int do_close) 1171 { 1172 Channel *c = channel_by_id(ssh, id); 1173 1174 if (c == NULL) { 1175 logit_f("%d: bad id", id); 1176 return; 1177 } 1178 c->detach_user = fn; 1179 c->detach_close = do_close; 1180 } 1181 1182 void 1183 channel_cancel_cleanup(struct ssh *ssh, int id) 1184 { 1185 Channel *c = channel_by_id(ssh, id); 1186 1187 if (c == NULL) { 1188 logit_f("%d: bad id", id); 1189 return; 1190 } 1191 c->detach_user = NULL; 1192 c->detach_close = 0; 1193 } 1194 1195 void 1196 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1197 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1198 { 1199 Channel *c = channel_lookup(ssh, id); 1200 1201 if (c == NULL) { 1202 logit_f("%d: bad id", id); 1203 return; 1204 } 1205 c->input_filter = ifn; 1206 c->output_filter = ofn; 1207 c->filter_ctx = ctx; 1208 c->filter_cleanup = cfn; 1209 } 1210 1211 void 1212 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1213 int extusage, int nonblock, int is_tty, u_int window_max) 1214 { 1215 Channel *c = channel_lookup(ssh, id); 1216 int r; 1217 1218 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1219 fatal("channel_activate for non-larval channel %d.", id); 1220 if (!c->have_remote_id) 1221 fatal_f("channel %d: no remote id", c->self); 1222 1223 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1224 c->type = SSH_CHANNEL_OPEN; 1225 channel_set_used_time(ssh, c); 1226 c->local_window = c->local_window_max = window_max; 1227 1228 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1229 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1230 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1231 (r = sshpkt_send(ssh)) != 0) 1232 fatal_fr(r, "channel %i", c->self); 1233 } 1234 1235 static void 1236 channel_pre_listener(struct ssh *ssh, Channel *c) 1237 { 1238 c->io_want = SSH_CHAN_IO_SOCK_R; 1239 } 1240 1241 static void 1242 channel_pre_connecting(struct ssh *ssh, Channel *c) 1243 { 1244 debug3("channel %d: waiting for connection", c->self); 1245 c->io_want = SSH_CHAN_IO_SOCK_W; 1246 } 1247 1248 static void 1249 channel_pre_open(struct ssh *ssh, Channel *c) 1250 { 1251 c->io_want = 0; 1252 if (c->istate == CHAN_INPUT_OPEN && 1253 c->remote_window > 0 && 1254 sshbuf_len(c->input) < c->remote_window && 1255 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1256 c->io_want |= SSH_CHAN_IO_RFD; 1257 if (c->ostate == CHAN_OUTPUT_OPEN || 1258 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1259 if (sshbuf_len(c->output) > 0) { 1260 c->io_want |= SSH_CHAN_IO_WFD; 1261 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1262 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1263 debug2("channel %d: " 1264 "obuf_empty delayed efd %d/(%zu)", c->self, 1265 c->efd, sshbuf_len(c->extended)); 1266 else 1267 chan_obuf_empty(ssh, c); 1268 } 1269 } 1270 /** XXX check close conditions, too */ 1271 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1272 c->ostate == CHAN_OUTPUT_CLOSED)) { 1273 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1274 sshbuf_len(c->extended) > 0) 1275 c->io_want |= SSH_CHAN_IO_EFD_W; 1276 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1277 (c->extended_usage == CHAN_EXTENDED_READ || 1278 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1279 sshbuf_len(c->extended) < c->remote_window) 1280 c->io_want |= SSH_CHAN_IO_EFD_R; 1281 } 1282 /* XXX: What about efd? races? */ 1283 } 1284 1285 /* 1286 * This is a special state for X11 authentication spoofing. An opened X11 1287 * connection (when authentication spoofing is being done) remains in this 1288 * state until the first packet has been completely read. The authentication 1289 * data in that packet is then substituted by the real data if it matches the 1290 * fake data, and the channel is put into normal mode. 1291 * XXX All this happens at the client side. 1292 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1293 */ 1294 static int 1295 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1296 { 1297 struct ssh_channels *sc = ssh->chanctxt; 1298 u_char *ucp; 1299 u_int proto_len, data_len; 1300 1301 /* Is this being called after the refusal deadline? */ 1302 if (sc->x11_refuse_time != 0 && 1303 monotime() >= sc->x11_refuse_time) { 1304 verbose("Rejected X11 connection after ForwardX11Timeout " 1305 "expired"); 1306 return -1; 1307 } 1308 1309 /* Check if the fixed size part of the packet is in buffer. */ 1310 if (sshbuf_len(b) < 12) 1311 return 0; 1312 1313 /* Parse the lengths of variable-length fields. */ 1314 ucp = sshbuf_mutable_ptr(b); 1315 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1316 proto_len = 256 * ucp[6] + ucp[7]; 1317 data_len = 256 * ucp[8] + ucp[9]; 1318 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1319 proto_len = ucp[6] + 256 * ucp[7]; 1320 data_len = ucp[8] + 256 * ucp[9]; 1321 } else { 1322 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1323 ucp[0]); 1324 return -1; 1325 } 1326 1327 /* Check if the whole packet is in buffer. */ 1328 if (sshbuf_len(b) < 1329 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1330 return 0; 1331 1332 /* Check if authentication protocol matches. */ 1333 if (proto_len != strlen(sc->x11_saved_proto) || 1334 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1335 debug2("X11 connection uses different authentication protocol."); 1336 return -1; 1337 } 1338 /* Check if authentication data matches our fake data. */ 1339 if (data_len != sc->x11_fake_data_len || 1340 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1341 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1342 debug2("X11 auth data does not match fake data."); 1343 return -1; 1344 } 1345 /* Check fake data length */ 1346 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1347 error("X11 fake_data_len %d != saved_data_len %d", 1348 sc->x11_fake_data_len, sc->x11_saved_data_len); 1349 return -1; 1350 } 1351 /* 1352 * Received authentication protocol and data match 1353 * our fake data. Substitute the fake data with real 1354 * data. 1355 */ 1356 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1357 sc->x11_saved_data, sc->x11_saved_data_len); 1358 return 1; 1359 } 1360 1361 void 1362 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1363 { 1364 debug3_f("channel %d: forcibly closing", c->self); 1365 if (c->istate == CHAN_INPUT_OPEN) 1366 chan_read_failed(ssh, c); 1367 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1368 sshbuf_reset(c->input); 1369 chan_ibuf_empty(ssh, c); 1370 } 1371 if (c->ostate == CHAN_OUTPUT_OPEN || 1372 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1373 sshbuf_reset(c->output); 1374 chan_write_failed(ssh, c); 1375 } 1376 if (c->detach_user) 1377 c->detach_user(ssh, c->self, 1, NULL); 1378 if (c->efd != -1) 1379 channel_close_fd(ssh, c, &c->efd); 1380 if (abandon) 1381 c->type = SSH_CHANNEL_ABANDONED; 1382 /* exempt from inactivity timeouts */ 1383 c->inactive_deadline = 0; 1384 c->lastused = 0; 1385 } 1386 1387 static void 1388 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1389 { 1390 int ret = x11_open_helper(ssh, c->output); 1391 1392 /* c->force_drain = 1; */ 1393 1394 if (ret == 1) { 1395 c->type = SSH_CHANNEL_OPEN; 1396 channel_set_used_time(ssh, c); 1397 channel_pre_open(ssh, c); 1398 } else if (ret == -1) { 1399 logit("X11 connection rejected because of wrong " 1400 "authentication."); 1401 debug2("X11 rejected %d i%d/o%d", 1402 c->self, c->istate, c->ostate); 1403 channel_force_close(ssh, c, 0); 1404 } 1405 } 1406 1407 static void 1408 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1409 { 1410 c->io_want = 0; 1411 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1412 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1413 c->io_want |= SSH_CHAN_IO_RFD; 1414 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1415 /* clear buffer immediately (discard any partial packet) */ 1416 sshbuf_reset(c->input); 1417 chan_ibuf_empty(ssh, c); 1418 /* Start output drain. XXX just kill chan? */ 1419 chan_rcvd_oclose(ssh, c); 1420 } 1421 if (c->ostate == CHAN_OUTPUT_OPEN || 1422 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1423 if (sshbuf_len(c->output) > 0) 1424 c->io_want |= SSH_CHAN_IO_WFD; 1425 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1426 chan_obuf_empty(ssh, c); 1427 } 1428 } 1429 1430 /* try to decode a socks4 header */ 1431 static int 1432 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1433 { 1434 const u_char *p; 1435 char *host; 1436 u_int len, have, i, found, need; 1437 char username[256]; 1438 struct { 1439 u_int8_t version; 1440 u_int8_t command; 1441 u_int16_t dest_port; 1442 struct in_addr dest_addr; 1443 } s4_req, s4_rsp; 1444 int r; 1445 1446 debug2("channel %d: decode socks4", c->self); 1447 1448 have = sshbuf_len(input); 1449 len = sizeof(s4_req); 1450 if (have < len) 1451 return 0; 1452 p = sshbuf_ptr(input); 1453 1454 need = 1; 1455 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1456 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1457 debug2("channel %d: socks4a request", c->self); 1458 /* ... and needs an extra string (the hostname) */ 1459 need = 2; 1460 } 1461 /* Check for terminating NUL on the string(s) */ 1462 for (found = 0, i = len; i < have; i++) { 1463 if (p[i] == '\0') { 1464 found++; 1465 if (found == need) 1466 break; 1467 } 1468 if (i > 1024) { 1469 /* the peer is probably sending garbage */ 1470 debug("channel %d: decode socks4: too long", 1471 c->self); 1472 return -1; 1473 } 1474 } 1475 if (found < need) 1476 return 0; 1477 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1478 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1479 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1480 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1481 debug_r(r, "channels %d: decode socks4", c->self); 1482 return -1; 1483 } 1484 have = sshbuf_len(input); 1485 p = sshbuf_ptr(input); 1486 if (memchr(p, '\0', have) == NULL) { 1487 error("channel %d: decode socks4: unterminated user", c->self); 1488 return -1; 1489 } 1490 len = strlen(p); 1491 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1492 len++; /* trailing '\0' */ 1493 strlcpy(username, p, sizeof(username)); 1494 if ((r = sshbuf_consume(input, len)) != 0) 1495 fatal_fr(r, "channel %d: consume", c->self); 1496 free(c->path); 1497 c->path = NULL; 1498 if (need == 1) { /* SOCKS4: one string */ 1499 host = inet_ntoa(s4_req.dest_addr); 1500 c->path = xstrdup(host); 1501 } else { /* SOCKS4A: two strings */ 1502 have = sshbuf_len(input); 1503 p = sshbuf_ptr(input); 1504 if (memchr(p, '\0', have) == NULL) { 1505 error("channel %d: decode socks4a: host not nul " 1506 "terminated", c->self); 1507 return -1; 1508 } 1509 len = strlen(p); 1510 debug2("channel %d: decode socks4a: host %s/%d", 1511 c->self, p, len); 1512 len++; /* trailing '\0' */ 1513 if (len > NI_MAXHOST) { 1514 error("channel %d: hostname \"%.100s\" too long", 1515 c->self, p); 1516 return -1; 1517 } 1518 c->path = xstrdup(p); 1519 if ((r = sshbuf_consume(input, len)) != 0) 1520 fatal_fr(r, "channel %d: consume", c->self); 1521 } 1522 c->host_port = ntohs(s4_req.dest_port); 1523 1524 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1525 c->self, c->path, c->host_port, s4_req.command); 1526 1527 if (s4_req.command != 1) { 1528 debug("channel %d: cannot handle: %s cn %d", 1529 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1530 return -1; 1531 } 1532 s4_rsp.version = 0; /* vn: 0 for reply */ 1533 s4_rsp.command = 90; /* cd: req granted */ 1534 s4_rsp.dest_port = 0; /* ignored */ 1535 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1536 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1537 fatal_fr(r, "channel %d: append reply", c->self); 1538 return 1; 1539 } 1540 1541 /* try to decode a socks5 header */ 1542 #define SSH_SOCKS5_AUTHDONE 0x1000 1543 #define SSH_SOCKS5_NOAUTH 0x00 1544 #define SSH_SOCKS5_IPV4 0x01 1545 #define SSH_SOCKS5_DOMAIN 0x03 1546 #define SSH_SOCKS5_IPV6 0x04 1547 #define SSH_SOCKS5_CONNECT 0x01 1548 #define SSH_SOCKS5_SUCCESS 0x00 1549 1550 static int 1551 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1552 { 1553 /* XXX use get/put_u8 instead of trusting struct padding */ 1554 struct { 1555 u_int8_t version; 1556 u_int8_t command; 1557 u_int8_t reserved; 1558 u_int8_t atyp; 1559 } s5_req, s5_rsp; 1560 u_int16_t dest_port; 1561 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1562 const u_char *p; 1563 u_int have, need, i, found, nmethods, addrlen, af; 1564 int r; 1565 1566 debug2("channel %d: decode socks5", c->self); 1567 p = sshbuf_ptr(input); 1568 if (p[0] != 0x05) 1569 return -1; 1570 have = sshbuf_len(input); 1571 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1572 /* format: ver | nmethods | methods */ 1573 if (have < 2) 1574 return 0; 1575 nmethods = p[1]; 1576 if (have < nmethods + 2) 1577 return 0; 1578 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1579 for (found = 0, i = 2; i < nmethods + 2; i++) { 1580 if (p[i] == SSH_SOCKS5_NOAUTH) { 1581 found = 1; 1582 break; 1583 } 1584 } 1585 if (!found) { 1586 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1587 c->self); 1588 return -1; 1589 } 1590 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1591 fatal_fr(r, "channel %d: consume", c->self); 1592 /* version, method */ 1593 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1594 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1595 fatal_fr(r, "channel %d: append reply", c->self); 1596 c->flags |= SSH_SOCKS5_AUTHDONE; 1597 debug2("channel %d: socks5 auth done", c->self); 1598 return 0; /* need more */ 1599 } 1600 debug2("channel %d: socks5 post auth", c->self); 1601 if (have < sizeof(s5_req)+1) 1602 return 0; /* need more */ 1603 memcpy(&s5_req, p, sizeof(s5_req)); 1604 if (s5_req.version != 0x05 || 1605 s5_req.command != SSH_SOCKS5_CONNECT || 1606 s5_req.reserved != 0x00) { 1607 debug2("channel %d: only socks5 connect supported", c->self); 1608 return -1; 1609 } 1610 switch (s5_req.atyp){ 1611 case SSH_SOCKS5_IPV4: 1612 addrlen = 4; 1613 af = AF_INET; 1614 break; 1615 case SSH_SOCKS5_DOMAIN: 1616 addrlen = p[sizeof(s5_req)]; 1617 af = -1; 1618 break; 1619 case SSH_SOCKS5_IPV6: 1620 addrlen = 16; 1621 af = AF_INET6; 1622 break; 1623 default: 1624 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1625 return -1; 1626 } 1627 need = sizeof(s5_req) + addrlen + 2; 1628 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1629 need++; 1630 if (have < need) 1631 return 0; 1632 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1633 fatal_fr(r, "channel %d: consume", c->self); 1634 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1635 /* host string length */ 1636 if ((r = sshbuf_consume(input, 1)) != 0) 1637 fatal_fr(r, "channel %d: consume", c->self); 1638 } 1639 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1640 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1641 debug_r(r, "channel %d: parse addr/port", c->self); 1642 return -1; 1643 } 1644 dest_addr[addrlen] = '\0'; 1645 free(c->path); 1646 c->path = NULL; 1647 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1648 if (addrlen >= NI_MAXHOST) { 1649 error("channel %d: dynamic request: socks5 hostname " 1650 "\"%.100s\" too long", c->self, dest_addr); 1651 return -1; 1652 } 1653 c->path = xstrdup(dest_addr); 1654 } else { 1655 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1656 return -1; 1657 c->path = xstrdup(ntop); 1658 } 1659 c->host_port = ntohs(dest_port); 1660 1661 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1662 c->self, c->path, c->host_port, s5_req.command); 1663 1664 s5_rsp.version = 0x05; 1665 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1666 s5_rsp.reserved = 0; /* ignored */ 1667 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1668 dest_port = 0; /* ignored */ 1669 1670 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1671 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1672 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1673 fatal_fr(r, "channel %d: append reply", c->self); 1674 return 1; 1675 } 1676 1677 Channel * 1678 channel_connect_stdio_fwd(struct ssh *ssh, 1679 const char *host_to_connect, int port_to_connect, 1680 int in, int out, int nonblock) 1681 { 1682 Channel *c; 1683 1684 debug_f("%s:%d", host_to_connect, port_to_connect); 1685 1686 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1687 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1688 0, "stdio-forward", nonblock); 1689 1690 c->path = xstrdup(host_to_connect); 1691 c->host_port = port_to_connect; 1692 c->listening_port = 0; 1693 c->force_drain = 1; 1694 1695 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1696 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1697 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1698 1699 return c; 1700 } 1701 1702 /* dynamic port forwarding */ 1703 static void 1704 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1705 { 1706 const u_char *p; 1707 u_int have; 1708 int ret; 1709 1710 c->io_want = 0; 1711 have = sshbuf_len(c->input); 1712 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1713 /* sshbuf_dump(c->input, stderr); */ 1714 /* check if the fixed size part of the packet is in buffer. */ 1715 if (have < 3) { 1716 /* need more */ 1717 c->io_want |= SSH_CHAN_IO_RFD; 1718 return; 1719 } 1720 /* try to guess the protocol */ 1721 p = sshbuf_ptr(c->input); 1722 /* XXX sshbuf_peek_u8? */ 1723 switch (p[0]) { 1724 case 0x04: 1725 ret = channel_decode_socks4(c, c->input, c->output); 1726 break; 1727 case 0x05: 1728 ret = channel_decode_socks5(c, c->input, c->output); 1729 break; 1730 default: 1731 ret = -1; 1732 break; 1733 } 1734 if (ret < 0) { 1735 chan_mark_dead(ssh, c); 1736 } else if (ret == 0) { 1737 debug2("channel %d: pre_dynamic: need more", c->self); 1738 /* need more */ 1739 c->io_want |= SSH_CHAN_IO_RFD; 1740 if (sshbuf_len(c->output)) 1741 c->io_want |= SSH_CHAN_IO_WFD; 1742 } else { 1743 /* switch to the next state */ 1744 c->type = SSH_CHANNEL_OPENING; 1745 port_open_helper(ssh, c, "direct-tcpip"); 1746 } 1747 } 1748 1749 /* simulate read-error */ 1750 static void 1751 rdynamic_close(struct ssh *ssh, Channel *c) 1752 { 1753 c->type = SSH_CHANNEL_OPEN; 1754 channel_force_close(ssh, c, 0); 1755 } 1756 1757 /* reverse dynamic port forwarding */ 1758 static void 1759 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1760 { 1761 const u_char *p; 1762 u_int have, len; 1763 int r, ret; 1764 1765 have = sshbuf_len(c->output); 1766 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1767 /* sshbuf_dump(c->output, stderr); */ 1768 /* EOF received */ 1769 if (c->flags & CHAN_EOF_RCVD) { 1770 if ((r = sshbuf_consume(c->output, have)) != 0) 1771 fatal_fr(r, "channel %d: consume", c->self); 1772 rdynamic_close(ssh, c); 1773 return; 1774 } 1775 /* check if the fixed size part of the packet is in buffer. */ 1776 if (have < 3) 1777 return; 1778 /* try to guess the protocol */ 1779 p = sshbuf_ptr(c->output); 1780 switch (p[0]) { 1781 case 0x04: 1782 /* switch input/output for reverse forwarding */ 1783 ret = channel_decode_socks4(c, c->output, c->input); 1784 break; 1785 case 0x05: 1786 ret = channel_decode_socks5(c, c->output, c->input); 1787 break; 1788 default: 1789 ret = -1; 1790 break; 1791 } 1792 if (ret < 0) { 1793 rdynamic_close(ssh, c); 1794 } else if (ret == 0) { 1795 debug2("channel %d: pre_rdynamic: need more", c->self); 1796 /* send socks request to peer */ 1797 len = sshbuf_len(c->input); 1798 if (len > 0 && len < c->remote_window) { 1799 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1800 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1801 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1802 (r = sshpkt_send(ssh)) != 0) { 1803 fatal_fr(r, "channel %i: rdynamic", c->self); 1804 } 1805 if ((r = sshbuf_consume(c->input, len)) != 0) 1806 fatal_fr(r, "channel %d: consume", c->self); 1807 c->remote_window -= len; 1808 } 1809 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1810 /* the connect failed */ 1811 rdynamic_close(ssh, c); 1812 } 1813 } 1814 1815 /* This is our fake X11 server socket. */ 1816 static void 1817 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1818 { 1819 Channel *nc; 1820 struct sockaddr_storage addr; 1821 int r, newsock, oerrno, remote_port; 1822 socklen_t addrlen; 1823 char buf[16384], *remote_ipaddr; 1824 1825 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1826 return; 1827 1828 debug("X11 connection requested."); 1829 addrlen = sizeof(addr); 1830 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1831 if (c->single_connection) { 1832 oerrno = errno; 1833 debug2("single_connection: closing X11 listener."); 1834 channel_close_fd(ssh, c, &c->sock); 1835 chan_mark_dead(ssh, c); 1836 errno = oerrno; 1837 } 1838 if (newsock == -1) { 1839 if (errno != EINTR && errno != EWOULDBLOCK && 1840 errno != ECONNABORTED) 1841 error("accept: %.100s", strerror(errno)); 1842 if (errno == EMFILE || errno == ENFILE) 1843 c->notbefore = monotime() + 1; 1844 return; 1845 } 1846 set_nodelay(newsock); 1847 remote_ipaddr = get_peer_ipaddr(newsock); 1848 remote_port = get_peer_port(newsock); 1849 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1850 remote_ipaddr, remote_port); 1851 1852 nc = channel_new(ssh, "x11-connection", 1853 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1854 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1855 open_preamble(ssh, __func__, nc, "x11"); 1856 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1857 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1858 fatal_fr(r, "channel %i: reply", c->self); 1859 } 1860 if ((r = sshpkt_send(ssh)) != 0) 1861 fatal_fr(r, "channel %i: send", c->self); 1862 free(remote_ipaddr); 1863 } 1864 1865 static void 1866 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1867 { 1868 char *local_ipaddr = get_local_ipaddr(c->sock); 1869 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1870 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1871 int remote_port = get_peer_port(c->sock); 1872 int r; 1873 1874 if (remote_port == -1) { 1875 /* Fake addr/port to appease peers that validate it (Tectia) */ 1876 free(remote_ipaddr); 1877 remote_ipaddr = xstrdup("127.0.0.1"); 1878 remote_port = 65535; 1879 } 1880 1881 free(c->remote_name); 1882 xasprintf(&c->remote_name, 1883 "%s: listening port %d for %.100s port %d, " 1884 "connect from %.200s port %d to %.100s port %d", 1885 rtype, c->listening_port, c->path, c->host_port, 1886 remote_ipaddr, remote_port, local_ipaddr, local_port); 1887 1888 open_preamble(ssh, __func__, c, rtype); 1889 if (strcmp(rtype, "direct-tcpip") == 0) { 1890 /* target host, port */ 1891 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1892 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1893 fatal_fr(r, "channel %i: reply", c->self); 1894 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1895 /* target path */ 1896 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1897 fatal_fr(r, "channel %i: reply", c->self); 1898 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1899 /* listen path */ 1900 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1901 fatal_fr(r, "channel %i: reply", c->self); 1902 } else { 1903 /* listen address, port */ 1904 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1905 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1906 fatal_fr(r, "channel %i: reply", c->self); 1907 } 1908 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1909 /* reserved for future owner/mode info */ 1910 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1911 fatal_fr(r, "channel %i: reply", c->self); 1912 } else { 1913 /* originator host and port */ 1914 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1915 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1916 fatal_fr(r, "channel %i: reply", c->self); 1917 } 1918 if ((r = sshpkt_send(ssh)) != 0) 1919 fatal_fr(r, "channel %i: send", c->self); 1920 free(remote_ipaddr); 1921 free(local_ipaddr); 1922 } 1923 1924 void 1925 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1926 { 1927 ssh->chanctxt->x11_refuse_time = refuse_time; 1928 } 1929 1930 /* 1931 * This socket is listening for connections to a forwarded TCP/IP port. 1932 */ 1933 static void 1934 channel_post_port_listener(struct ssh *ssh, Channel *c) 1935 { 1936 Channel *nc; 1937 struct sockaddr_storage addr; 1938 int newsock, nextstate; 1939 socklen_t addrlen; 1940 char *rtype; 1941 1942 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1943 return; 1944 1945 debug("Connection to port %d forwarding to %.100s port %d requested.", 1946 c->listening_port, c->path, c->host_port); 1947 1948 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1949 nextstate = SSH_CHANNEL_OPENING; 1950 rtype = "forwarded-tcpip"; 1951 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1952 nextstate = SSH_CHANNEL_OPENING; 1953 rtype = "forwarded-streamlocal@openssh.com"; 1954 } else if (c->host_port == PORT_STREAMLOCAL) { 1955 nextstate = SSH_CHANNEL_OPENING; 1956 rtype = "direct-streamlocal@openssh.com"; 1957 } else if (c->host_port == 0) { 1958 nextstate = SSH_CHANNEL_DYNAMIC; 1959 rtype = "dynamic-tcpip"; 1960 } else { 1961 nextstate = SSH_CHANNEL_OPENING; 1962 rtype = "direct-tcpip"; 1963 } 1964 1965 addrlen = sizeof(addr); 1966 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1967 if (newsock == -1) { 1968 if (errno != EINTR && errno != EWOULDBLOCK && 1969 errno != ECONNABORTED) 1970 error("accept: %.100s", strerror(errno)); 1971 if (errno == EMFILE || errno == ENFILE) 1972 c->notbefore = monotime() + 1; 1973 return; 1974 } 1975 if (c->host_port != PORT_STREAMLOCAL) 1976 set_nodelay(newsock); 1977 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1978 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1979 nc->listening_port = c->listening_port; 1980 nc->host_port = c->host_port; 1981 if (c->path != NULL) 1982 nc->path = xstrdup(c->path); 1983 1984 if (nextstate != SSH_CHANNEL_DYNAMIC) 1985 port_open_helper(ssh, nc, rtype); 1986 } 1987 1988 /* 1989 * This is the authentication agent socket listening for connections from 1990 * clients. 1991 */ 1992 static void 1993 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1994 { 1995 Channel *nc; 1996 int r, newsock; 1997 struct sockaddr_storage addr; 1998 socklen_t addrlen; 1999 2000 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2001 return; 2002 2003 addrlen = sizeof(addr); 2004 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2005 if (newsock == -1) { 2006 error("accept from auth socket: %.100s", strerror(errno)); 2007 if (errno == EMFILE || errno == ENFILE) 2008 c->notbefore = monotime() + 1; 2009 return; 2010 } 2011 nc = channel_new(ssh, "agent-connection", 2012 SSH_CHANNEL_OPENING, newsock, newsock, -1, 2013 c->local_window_max, c->local_maxpacket, 2014 0, "accepted auth socket", 1); 2015 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 2016 if ((r = sshpkt_send(ssh)) != 0) 2017 fatal_fr(r, "channel %i", c->self); 2018 } 2019 2020 static void 2021 channel_post_connecting(struct ssh *ssh, Channel *c) 2022 { 2023 int err = 0, sock, isopen, r; 2024 socklen_t sz = sizeof(err); 2025 2026 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2027 return; 2028 if (!c->have_remote_id) 2029 fatal_f("channel %d: no remote id", c->self); 2030 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2031 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2032 2033 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2034 err = errno; 2035 error("getsockopt SO_ERROR failed"); 2036 } 2037 2038 if (err == 0) { 2039 /* Non-blocking connection completed */ 2040 debug("channel %d: connected to %s port %d", 2041 c->self, c->connect_ctx.host, c->connect_ctx.port); 2042 channel_connect_ctx_free(&c->connect_ctx); 2043 c->type = SSH_CHANNEL_OPEN; 2044 channel_set_used_time(ssh, c); 2045 if (isopen) { 2046 /* no message necessary */ 2047 } else { 2048 if ((r = sshpkt_start(ssh, 2049 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2050 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2051 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2052 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2053 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2054 (r = sshpkt_send(ssh)) != 0) 2055 fatal_fr(r, "channel %i open confirm", c->self); 2056 } 2057 return; 2058 } 2059 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2060 return; 2061 2062 /* Non-blocking connection failed */ 2063 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2064 2065 /* Try next address, if any */ 2066 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2067 /* Exhausted all addresses for this destination */ 2068 error("connect_to %.100s port %d: failed.", 2069 c->connect_ctx.host, c->connect_ctx.port); 2070 channel_connect_ctx_free(&c->connect_ctx); 2071 if (isopen) { 2072 rdynamic_close(ssh, c); 2073 } else { 2074 if ((r = sshpkt_start(ssh, 2075 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2076 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2077 (r = sshpkt_put_u32(ssh, 2078 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2079 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2080 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2081 (r = sshpkt_send(ssh)) != 0) 2082 fatal_fr(r, "channel %i: failure", c->self); 2083 chan_mark_dead(ssh, c); 2084 } 2085 } 2086 2087 /* New non-blocking connection in progress */ 2088 close(c->sock); 2089 c->sock = c->rfd = c->wfd = sock; 2090 } 2091 2092 static int 2093 channel_handle_rfd(struct ssh *ssh, Channel *c) 2094 { 2095 char buf[CHAN_RBUF]; 2096 ssize_t len; 2097 int r; 2098 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2099 2100 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2101 return 1; /* Shouldn't happen */ 2102 if ((avail = sshbuf_avail(c->input)) == 0) 2103 return 1; /* Shouldn't happen */ 2104 2105 /* 2106 * For "simple" channels (i.e. not datagram or filtered), we can 2107 * read directly to the channel buffer. 2108 */ 2109 if (c->input_filter == NULL && !c->datagram) { 2110 /* Only OPEN channels have valid rwin */ 2111 if (c->type == SSH_CHANNEL_OPEN) { 2112 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2113 return 1; /* shouldn't happen */ 2114 if (maxlen > c->remote_window - have) 2115 maxlen = c->remote_window - have; 2116 } 2117 if (maxlen > avail) 2118 maxlen = avail; 2119 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2120 if (errno == EINTR || errno == EAGAIN) 2121 return 1; 2122 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2123 c->self, c->rfd, maxlen, ssh_err(r)); 2124 goto rfail; 2125 } 2126 if (nr != 0) 2127 channel_set_used_time(ssh, c); 2128 return 1; 2129 } 2130 2131 len = read(c->rfd, buf, sizeof(buf)); 2132 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2133 return 1; 2134 if (len <= 0) { 2135 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2136 c->self, c->rfd, len, 2137 len == 0 ? "closed" : strerror(errno)); 2138 rfail: 2139 if (c->type != SSH_CHANNEL_OPEN) { 2140 debug2("channel %d: not open", c->self); 2141 chan_mark_dead(ssh, c); 2142 return -1; 2143 } else { 2144 chan_read_failed(ssh, c); 2145 } 2146 return -1; 2147 } 2148 channel_set_used_time(ssh, c); 2149 if (c->input_filter != NULL) { 2150 if (c->input_filter(ssh, c, buf, len) == -1) { 2151 debug2("channel %d: filter stops", c->self); 2152 chan_read_failed(ssh, c); 2153 } 2154 } else if (c->datagram) { 2155 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2156 fatal_fr(r, "channel %i: put datagram", c->self); 2157 } 2158 return 1; 2159 } 2160 2161 static int 2162 channel_handle_wfd(struct ssh *ssh, Channel *c) 2163 { 2164 struct termios tio; 2165 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2166 size_t dlen, olen = 0; 2167 int r, len; 2168 2169 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2170 return 1; 2171 if (sshbuf_len(c->output) == 0) 2172 return 1; 2173 2174 /* Send buffered output data to the socket. */ 2175 olen = sshbuf_len(c->output); 2176 if (c->output_filter != NULL) { 2177 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2178 debug2("channel %d: filter stops", c->self); 2179 if (c->type != SSH_CHANNEL_OPEN) 2180 chan_mark_dead(ssh, c); 2181 else 2182 chan_write_failed(ssh, c); 2183 return -1; 2184 } 2185 } else if (c->datagram) { 2186 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2187 fatal_fr(r, "channel %i: get datagram", c->self); 2188 buf = data; 2189 } else { 2190 buf = data = sshbuf_mutable_ptr(c->output); 2191 dlen = sshbuf_len(c->output); 2192 } 2193 2194 if (c->datagram) { 2195 /* ignore truncated writes, datagrams might get lost */ 2196 len = write(c->wfd, buf, dlen); 2197 free(data); 2198 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2199 return 1; 2200 if (len <= 0) 2201 goto write_fail; 2202 goto out; 2203 } 2204 2205 len = write(c->wfd, buf, dlen); 2206 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2207 return 1; 2208 if (len <= 0) { 2209 write_fail: 2210 if (c->type != SSH_CHANNEL_OPEN) { 2211 debug2("channel %d: not open", c->self); 2212 chan_mark_dead(ssh, c); 2213 return -1; 2214 } else { 2215 chan_write_failed(ssh, c); 2216 } 2217 return -1; 2218 } 2219 channel_set_used_time(ssh, c); 2220 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2221 if (tcgetattr(c->wfd, &tio) == 0 && 2222 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2223 /* 2224 * Simulate echo to reduce the impact of 2225 * traffic analysis. We need to match the 2226 * size of a SSH2_MSG_CHANNEL_DATA message 2227 * (4 byte channel id + buf) 2228 */ 2229 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2230 (r = sshpkt_send(ssh)) != 0) 2231 fatal_fr(r, "channel %i: ignore", c->self); 2232 } 2233 } 2234 if ((r = sshbuf_consume(c->output, len)) != 0) 2235 fatal_fr(r, "channel %i: consume", c->self); 2236 out: 2237 c->local_consumed += olen - sshbuf_len(c->output); 2238 2239 return 1; 2240 } 2241 2242 static int 2243 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2244 { 2245 int r; 2246 ssize_t len; 2247 2248 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2249 return 1; 2250 if (sshbuf_len(c->extended) == 0) 2251 return 1; 2252 2253 len = write(c->efd, sshbuf_ptr(c->extended), 2254 sshbuf_len(c->extended)); 2255 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2256 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2257 return 1; 2258 if (len <= 0) { 2259 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2260 channel_close_fd(ssh, c, &c->efd); 2261 } else { 2262 if ((r = sshbuf_consume(c->extended, len)) != 0) 2263 fatal_fr(r, "channel %i: consume", c->self); 2264 c->local_consumed += len; 2265 channel_set_used_time(ssh, c); 2266 } 2267 return 1; 2268 } 2269 2270 static int 2271 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2272 { 2273 char buf[CHAN_RBUF]; 2274 int r; 2275 ssize_t len; 2276 2277 if ((c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2278 return 1; 2279 2280 len = read(c->efd, buf, sizeof(buf)); 2281 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2282 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2283 return 1; 2284 if (len <= 0) { 2285 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2286 channel_close_fd(ssh, c, &c->efd); 2287 return 1; 2288 } 2289 channel_set_used_time(ssh, c); 2290 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2291 debug3("channel %d: discard efd", c->self); 2292 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2293 fatal_fr(r, "channel %i: append", c->self); 2294 return 1; 2295 } 2296 2297 static int 2298 channel_handle_efd(struct ssh *ssh, Channel *c) 2299 { 2300 if (c->efd == -1) 2301 return 1; 2302 2303 /** XXX handle drain efd, too */ 2304 2305 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2306 return channel_handle_efd_write(ssh, c); 2307 else if (c->extended_usage == CHAN_EXTENDED_READ || 2308 c->extended_usage == CHAN_EXTENDED_IGNORE) 2309 return channel_handle_efd_read(ssh, c); 2310 2311 return 1; 2312 } 2313 2314 static int 2315 channel_check_window(struct ssh *ssh, Channel *c) 2316 { 2317 int r; 2318 2319 if (c->type == SSH_CHANNEL_OPEN && 2320 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2321 ((c->local_window_max - c->local_window > 2322 c->local_maxpacket*3) || 2323 c->local_window < c->local_window_max/2) && 2324 c->local_consumed > 0) { 2325 if (!c->have_remote_id) 2326 fatal_f("channel %d: no remote id", c->self); 2327 if ((r = sshpkt_start(ssh, 2328 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2329 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2330 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2331 (r = sshpkt_send(ssh)) != 0) { 2332 fatal_fr(r, "channel %i", c->self); 2333 } 2334 debug2("channel %d: window %d sent adjust %d", c->self, 2335 c->local_window, c->local_consumed); 2336 c->local_window += c->local_consumed; 2337 c->local_consumed = 0; 2338 } 2339 return 1; 2340 } 2341 2342 static void 2343 channel_post_open(struct ssh *ssh, Channel *c) 2344 { 2345 channel_handle_rfd(ssh, c); 2346 channel_handle_wfd(ssh, c); 2347 channel_handle_efd(ssh, c); 2348 channel_check_window(ssh, c); 2349 } 2350 2351 static u_int 2352 read_mux(struct ssh *ssh, Channel *c, u_int need) 2353 { 2354 char buf[CHAN_RBUF]; 2355 ssize_t len; 2356 u_int rlen; 2357 int r; 2358 2359 if (sshbuf_len(c->input) < need) { 2360 rlen = need - sshbuf_len(c->input); 2361 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2362 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2363 return sshbuf_len(c->input); 2364 if (len <= 0) { 2365 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2366 c->self, c->rfd, len); 2367 chan_read_failed(ssh, c); 2368 return 0; 2369 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2370 fatal_fr(r, "channel %i: append", c->self); 2371 } 2372 return sshbuf_len(c->input); 2373 } 2374 2375 static void 2376 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2377 { 2378 u_int need; 2379 2380 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2381 return; 2382 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2383 return; 2384 if (c->mux_pause) 2385 return; 2386 2387 /* 2388 * Don't not read past the precise end of packets to 2389 * avoid disrupting fd passing. 2390 */ 2391 if (read_mux(ssh, c, 4) < 4) /* read header */ 2392 return; 2393 /* XXX sshbuf_peek_u32 */ 2394 need = PEEK_U32(sshbuf_ptr(c->input)); 2395 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2396 if (need > CHANNEL_MUX_MAX_PACKET) { 2397 debug2("channel %d: packet too big %u > %u", 2398 c->self, CHANNEL_MUX_MAX_PACKET, need); 2399 chan_rcvd_oclose(ssh, c); 2400 return; 2401 } 2402 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2403 return; 2404 if (c->mux_rcb(ssh, c) != 0) { 2405 debug("channel %d: mux_rcb failed", c->self); 2406 chan_mark_dead(ssh, c); 2407 return; 2408 } 2409 } 2410 2411 static void 2412 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2413 { 2414 ssize_t len; 2415 int r; 2416 2417 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2418 return; 2419 if (sshbuf_len(c->output) == 0) 2420 return; 2421 2422 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2423 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2424 return; 2425 if (len <= 0) { 2426 chan_mark_dead(ssh, c); 2427 return; 2428 } 2429 if ((r = sshbuf_consume(c->output, len)) != 0) 2430 fatal_fr(r, "channel %i: consume", c->self); 2431 } 2432 2433 static void 2434 channel_post_mux_client(struct ssh *ssh, Channel *c) 2435 { 2436 channel_post_mux_client_read(ssh, c); 2437 channel_post_mux_client_write(ssh, c); 2438 } 2439 2440 static void 2441 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2442 { 2443 Channel *nc; 2444 struct sockaddr_storage addr; 2445 socklen_t addrlen; 2446 int newsock; 2447 uid_t euid; 2448 gid_t egid; 2449 2450 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2451 return; 2452 2453 debug("multiplexing control connection"); 2454 2455 /* 2456 * Accept connection on control socket 2457 */ 2458 memset(&addr, 0, sizeof(addr)); 2459 addrlen = sizeof(addr); 2460 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2461 &addrlen)) == -1) { 2462 error_f("accept: %s", strerror(errno)); 2463 if (errno == EMFILE || errno == ENFILE) 2464 c->notbefore = monotime() + 1; 2465 return; 2466 } 2467 2468 if (getpeereid(newsock, &euid, &egid) == -1) { 2469 error_f("getpeereid failed: %s", strerror(errno)); 2470 close(newsock); 2471 return; 2472 } 2473 if ((euid != 0) && (getuid() != euid)) { 2474 error("multiplex uid mismatch: peer euid %u != uid %u", 2475 (u_int)euid, (u_int)getuid()); 2476 close(newsock); 2477 return; 2478 } 2479 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2480 newsock, newsock, -1, c->local_window_max, 2481 c->local_maxpacket, 0, "mux-control", 1); 2482 nc->mux_rcb = c->mux_rcb; 2483 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2484 /* establish state */ 2485 nc->mux_rcb(ssh, nc); 2486 /* mux state transitions must not elicit protocol messages */ 2487 nc->flags |= CHAN_LOCAL; 2488 } 2489 2490 static void 2491 channel_handler_init(struct ssh_channels *sc) 2492 { 2493 chan_fn **pre, **post; 2494 2495 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2496 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2497 fatal_f("allocation failed"); 2498 2499 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2500 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2501 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2502 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2503 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2504 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2505 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2506 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2507 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2508 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2509 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2510 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2511 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2512 2513 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2514 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2515 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2516 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2517 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2518 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2519 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2520 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2521 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2522 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2523 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2524 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2525 2526 sc->channel_pre = pre; 2527 sc->channel_post = post; 2528 } 2529 2530 /* gc dead channels */ 2531 static void 2532 channel_garbage_collect(struct ssh *ssh, Channel *c) 2533 { 2534 if (c == NULL) 2535 return; 2536 if (c->detach_user != NULL) { 2537 if (!chan_is_dead(ssh, c, c->detach_close)) 2538 return; 2539 2540 debug2("channel %d: gc: notify user", c->self); 2541 c->detach_user(ssh, c->self, 0, NULL); 2542 /* if we still have a callback */ 2543 if (c->detach_user != NULL) 2544 return; 2545 debug2("channel %d: gc: user detached", c->self); 2546 } 2547 if (!chan_is_dead(ssh, c, 1)) 2548 return; 2549 debug2("channel %d: garbage collecting", c->self); 2550 channel_free(ssh, c); 2551 } 2552 2553 enum channel_table { CHAN_PRE, CHAN_POST }; 2554 2555 static void 2556 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2557 { 2558 struct ssh_channels *sc = ssh->chanctxt; 2559 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2560 u_int i, oalloc; 2561 Channel *c; 2562 time_t now; 2563 2564 now = monotime(); 2565 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2566 c = sc->channels[i]; 2567 if (c == NULL) 2568 continue; 2569 /* Try to keep IO going while rekeying */ 2570 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2571 continue; 2572 if (c->delayed) { 2573 if (table == CHAN_PRE) 2574 c->delayed = 0; 2575 else 2576 continue; 2577 } 2578 if (ftab[c->type] != NULL) { 2579 if (table == CHAN_PRE && c->type == SSH_CHANNEL_OPEN && 2580 channel_get_expiry(ssh, c) != 0 && 2581 now >= channel_get_expiry(ssh, c)) { 2582 /* channel closed for inactivity */ 2583 verbose("channel %d: closing after %u seconds " 2584 "of inactivity", c->self, 2585 c->inactive_deadline); 2586 channel_force_close(ssh, c, 1); 2587 } else if (c->notbefore <= now) { 2588 /* Run handlers that are not paused. */ 2589 (*ftab[c->type])(ssh, c); 2590 /* inactivity timeouts must interrupt poll() */ 2591 if (timeout != NULL && 2592 c->type == SSH_CHANNEL_OPEN && 2593 channel_get_expiry(ssh, c) != 0) { 2594 ptimeout_deadline_monotime(timeout, 2595 channel_get_expiry(ssh, c)); 2596 } 2597 } else if (timeout != NULL) { 2598 /* 2599 * Arrange for poll() wakeup when channel pause 2600 * timer expires. 2601 */ 2602 ptimeout_deadline_monotime(timeout, 2603 c->notbefore); 2604 } 2605 } 2606 channel_garbage_collect(ssh, c); 2607 } 2608 } 2609 2610 /* 2611 * Create sockets before preparing IO. 2612 * This is necessary for things that need to happen after reading 2613 * the network-input but need to be completed before IO event setup, e.g. 2614 * because they may create new channels. 2615 */ 2616 static void 2617 channel_before_prepare_io(struct ssh *ssh) 2618 { 2619 struct ssh_channels *sc = ssh->chanctxt; 2620 Channel *c; 2621 u_int i, oalloc; 2622 2623 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2624 c = sc->channels[i]; 2625 if (c == NULL) 2626 continue; 2627 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2628 channel_before_prepare_io_rdynamic(ssh, c); 2629 } 2630 } 2631 2632 static void 2633 dump_channel_poll(const char *func, const char *what, Channel *c, 2634 u_int pollfd_offset, struct pollfd *pfd) 2635 { 2636 #ifdef DEBUG_CHANNEL_POLL 2637 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2638 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2639 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2640 c->rfd, c->wfd, c->efd, c->sock, 2641 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2642 c->io_want, c->io_ready, 2643 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2644 #endif 2645 } 2646 2647 /* Prepare pollfd entries for a single channel */ 2648 static void 2649 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2650 struct pollfd *pfd, u_int npfd) 2651 { 2652 u_int ev, p = *next_pollfd; 2653 2654 if (c == NULL) 2655 return; 2656 if (p + 4 > npfd) { 2657 /* Shouldn't happen */ 2658 fatal_f("channel %d: bad pfd offset %u (max %u)", 2659 c->self, p, npfd); 2660 } 2661 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2662 /* 2663 * prepare c->rfd 2664 * 2665 * This is a special case, since c->rfd might be the same as 2666 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2667 * IO too. 2668 */ 2669 if (c->rfd != -1) { 2670 ev = 0; 2671 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2672 ev |= POLLIN; 2673 /* rfd == wfd */ 2674 if (c->wfd == c->rfd) { 2675 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2676 ev |= POLLOUT; 2677 } 2678 /* rfd == efd */ 2679 if (c->efd == c->rfd) { 2680 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2681 ev |= POLLIN; 2682 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2683 ev |= POLLOUT; 2684 } 2685 /* rfd == sock */ 2686 if (c->sock == c->rfd) { 2687 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2688 ev |= POLLIN; 2689 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2690 ev |= POLLOUT; 2691 } 2692 /* Pack a pfd entry if any event armed for this fd */ 2693 if (ev != 0) { 2694 c->pfds[0] = p; 2695 pfd[p].fd = c->rfd; 2696 pfd[p].events = ev; 2697 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2698 p++; 2699 } 2700 } 2701 /* prepare c->wfd if wanting IO and not already handled above */ 2702 if (c->wfd != -1 && c->rfd != c->wfd) { 2703 ev = 0; 2704 if ((c->io_want & SSH_CHAN_IO_WFD)) 2705 ev |= POLLOUT; 2706 /* Pack a pfd entry if any event armed for this fd */ 2707 if (ev != 0) { 2708 c->pfds[1] = p; 2709 pfd[p].fd = c->wfd; 2710 pfd[p].events = ev; 2711 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2712 p++; 2713 } 2714 } 2715 /* prepare c->efd if wanting IO and not already handled above */ 2716 if (c->efd != -1 && c->rfd != c->efd) { 2717 ev = 0; 2718 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2719 ev |= POLLIN; 2720 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2721 ev |= POLLOUT; 2722 /* Pack a pfd entry if any event armed for this fd */ 2723 if (ev != 0) { 2724 c->pfds[2] = p; 2725 pfd[p].fd = c->efd; 2726 pfd[p].events = ev; 2727 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2728 p++; 2729 } 2730 } 2731 /* prepare c->sock if wanting IO and not already handled above */ 2732 if (c->sock != -1 && c->rfd != c->sock) { 2733 ev = 0; 2734 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2735 ev |= POLLIN; 2736 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2737 ev |= POLLOUT; 2738 /* Pack a pfd entry if any event armed for this fd */ 2739 if (ev != 0) { 2740 c->pfds[3] = p; 2741 pfd[p].fd = c->sock; 2742 pfd[p].events = 0; 2743 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2744 p++; 2745 } 2746 } 2747 *next_pollfd = p; 2748 } 2749 2750 /* * Allocate/prepare poll structure */ 2751 void 2752 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2753 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2754 { 2755 struct ssh_channels *sc = ssh->chanctxt; 2756 u_int i, oalloc, p, npfd = npfd_reserved; 2757 2758 channel_before_prepare_io(ssh); /* might create a new channel */ 2759 /* clear out I/O flags from last poll */ 2760 for (i = 0; i < sc->channels_alloc; i++) { 2761 if (sc->channels[i] == NULL) 2762 continue; 2763 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2764 } 2765 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2766 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2767 fatal_f("too many channels"); /* shouldn't happen */ 2768 npfd += sc->channels_alloc * 4; 2769 if (npfd > *npfd_allocp) { 2770 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2771 npfd, sizeof(**pfdp)); 2772 *npfd_allocp = npfd; 2773 } 2774 *npfd_activep = npfd_reserved; 2775 oalloc = sc->channels_alloc; 2776 2777 channel_handler(ssh, CHAN_PRE, timeout); 2778 2779 if (oalloc != sc->channels_alloc) { 2780 /* shouldn't happen */ 2781 fatal_f("channels_alloc changed during CHAN_PRE " 2782 "(was %u, now %u)", oalloc, sc->channels_alloc); 2783 } 2784 2785 /* Prepare pollfd */ 2786 p = npfd_reserved; 2787 for (i = 0; i < sc->channels_alloc; i++) 2788 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2789 *npfd_activep = p; 2790 } 2791 2792 static void 2793 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2794 const char *what, u_int revents_mask, u_int ready) 2795 { 2796 struct pollfd *pfd = &pfds[p]; 2797 2798 if (fd == -1) 2799 return; 2800 if (p == -1 || (u_int)p >= npfd) 2801 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2802 dump_channel_poll(__func__, what, c, p, pfd); 2803 if (pfd->fd != fd) { 2804 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2805 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2806 c->rfd, c->wfd, c->efd, c->sock); 2807 } 2808 if ((pfd->revents & POLLNVAL) != 0) { 2809 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2810 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2811 } 2812 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2813 c->io_ready |= ready & c->io_want; 2814 } 2815 2816 /* 2817 * After poll, perform any appropriate operations for channels which have 2818 * events pending. 2819 */ 2820 void 2821 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2822 { 2823 struct ssh_channels *sc = ssh->chanctxt; 2824 u_int i; 2825 int p; 2826 Channel *c; 2827 2828 #ifdef DEBUG_CHANNEL_POLL 2829 for (p = 0; p < (int)npfd; p++) { 2830 if (pfd[p].revents == 0) 2831 continue; 2832 debug_f("pfd[%u].fd %d rev 0x%04x", 2833 p, pfd[p].fd, pfd[p].revents); 2834 } 2835 #endif 2836 2837 /* Convert pollfd into c->io_ready */ 2838 for (i = 0; i < sc->channels_alloc; i++) { 2839 c = sc->channels[i]; 2840 if (c == NULL) 2841 continue; 2842 /* if rfd is shared with efd/sock then wfd should be too */ 2843 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2844 (c->rfd == c->efd || c->rfd == c->sock)) { 2845 /* Shouldn't happen */ 2846 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2847 c->self, c->rfd, c->wfd, c->efd, c->sock); 2848 } 2849 c->io_ready = 0; 2850 /* rfd, potentially shared with wfd, efd and sock */ 2851 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2852 fd_ready(c, p, pfd, npfd, c->rfd, 2853 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2854 if (c->rfd == c->wfd) { 2855 fd_ready(c, p, pfd, npfd, c->wfd, 2856 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2857 } 2858 if (c->rfd == c->efd) { 2859 fd_ready(c, p, pfd, npfd, c->efd, 2860 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2861 fd_ready(c, p, pfd, npfd, c->efd, 2862 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2863 } 2864 if (c->rfd == c->sock) { 2865 fd_ready(c, p, pfd, npfd, c->sock, 2866 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2867 fd_ready(c, p, pfd, npfd, c->sock, 2868 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2869 } 2870 dump_channel_poll(__func__, "rfd", c, p, pfd); 2871 } 2872 /* wfd */ 2873 if (c->wfd != -1 && c->wfd != c->rfd && 2874 (p = c->pfds[1]) != -1) { 2875 fd_ready(c, p, pfd, npfd, c->wfd, 2876 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2877 dump_channel_poll(__func__, "wfd", c, p, pfd); 2878 } 2879 /* efd */ 2880 if (c->efd != -1 && c->efd != c->rfd && 2881 (p = c->pfds[2]) != -1) { 2882 fd_ready(c, p, pfd, npfd, c->efd, 2883 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2884 fd_ready(c, p, pfd, npfd, c->efd, 2885 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2886 dump_channel_poll(__func__, "efd", c, p, pfd); 2887 } 2888 /* sock */ 2889 if (c->sock != -1 && c->sock != c->rfd && 2890 (p = c->pfds[3]) != -1) { 2891 fd_ready(c, p, pfd, npfd, c->sock, 2892 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2893 fd_ready(c, p, pfd, npfd, c->sock, 2894 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2895 dump_channel_poll(__func__, "sock", c, p, pfd); 2896 } 2897 } 2898 channel_handler(ssh, CHAN_POST, NULL); 2899 } 2900 2901 /* 2902 * Enqueue data for channels with open or draining c->input. 2903 * Returns non-zero if a packet was enqueued. 2904 */ 2905 static int 2906 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2907 { 2908 size_t len, plen; 2909 const u_char *pkt; 2910 int r; 2911 2912 if ((len = sshbuf_len(c->input)) == 0) { 2913 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2914 /* 2915 * input-buffer is empty and read-socket shutdown: 2916 * tell peer, that we will not send more data: 2917 * send IEOF. 2918 * hack for extended data: delay EOF if EFD still 2919 * in use. 2920 */ 2921 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2922 debug2("channel %d: " 2923 "ibuf_empty delayed efd %d/(%zu)", 2924 c->self, c->efd, sshbuf_len(c->extended)); 2925 else 2926 chan_ibuf_empty(ssh, c); 2927 } 2928 return 0; 2929 } 2930 2931 if (!c->have_remote_id) 2932 fatal_f("channel %d: no remote id", c->self); 2933 2934 if (c->datagram) { 2935 /* Check datagram will fit; drop if not */ 2936 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2937 fatal_fr(r, "channel %i: get datagram", c->self); 2938 /* 2939 * XXX this does tail-drop on the datagram queue which is 2940 * usually suboptimal compared to head-drop. Better to have 2941 * backpressure at read time? (i.e. read + discard) 2942 */ 2943 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2944 debug("channel %d: datagram too big", c->self); 2945 return 0; 2946 } 2947 /* Enqueue it */ 2948 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2949 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2950 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2951 (r = sshpkt_send(ssh)) != 0) 2952 fatal_fr(r, "channel %i: send datagram", c->self); 2953 c->remote_window -= plen; 2954 return 1; 2955 } 2956 2957 /* Enqueue packet for buffered data. */ 2958 if (len > c->remote_window) 2959 len = c->remote_window; 2960 if (len > c->remote_maxpacket) 2961 len = c->remote_maxpacket; 2962 if (len == 0) 2963 return 0; 2964 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2965 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2966 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2967 (r = sshpkt_send(ssh)) != 0) 2968 fatal_fr(r, "channel %i: send data", c->self); 2969 if ((r = sshbuf_consume(c->input, len)) != 0) 2970 fatal_fr(r, "channel %i: consume", c->self); 2971 c->remote_window -= len; 2972 return 1; 2973 } 2974 2975 /* 2976 * Enqueue data for channels with open c->extended in read mode. 2977 * Returns non-zero if a packet was enqueued. 2978 */ 2979 static int 2980 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2981 { 2982 size_t len; 2983 int r; 2984 2985 if ((len = sshbuf_len(c->extended)) == 0) 2986 return 0; 2987 2988 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2989 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2990 if (len > c->remote_window) 2991 len = c->remote_window; 2992 if (len > c->remote_maxpacket) 2993 len = c->remote_maxpacket; 2994 if (len == 0) 2995 return 0; 2996 if (!c->have_remote_id) 2997 fatal_f("channel %d: no remote id", c->self); 2998 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2999 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3000 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 3001 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 3002 (r = sshpkt_send(ssh)) != 0) 3003 fatal_fr(r, "channel %i: data", c->self); 3004 if ((r = sshbuf_consume(c->extended, len)) != 0) 3005 fatal_fr(r, "channel %i: consume", c->self); 3006 c->remote_window -= len; 3007 debug2("channel %d: sent ext data %zu", c->self, len); 3008 return 1; 3009 } 3010 3011 /* 3012 * If there is data to send to the connection, enqueue some of it now. 3013 * Returns non-zero if data was enqueued. 3014 */ 3015 int 3016 channel_output_poll(struct ssh *ssh) 3017 { 3018 struct ssh_channels *sc = ssh->chanctxt; 3019 Channel *c; 3020 u_int i; 3021 int ret = 0; 3022 3023 for (i = 0; i < sc->channels_alloc; i++) { 3024 c = sc->channels[i]; 3025 if (c == NULL) 3026 continue; 3027 3028 /* 3029 * We are only interested in channels that can have buffered 3030 * incoming data. 3031 */ 3032 if (c->type != SSH_CHANNEL_OPEN) 3033 continue; 3034 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3035 /* XXX is this true? */ 3036 debug3("channel %d: will not send data after close", 3037 c->self); 3038 continue; 3039 } 3040 3041 /* Get the amount of buffered data for this channel. */ 3042 if (c->istate == CHAN_INPUT_OPEN || 3043 c->istate == CHAN_INPUT_WAIT_DRAIN) 3044 ret |= channel_output_poll_input_open(ssh, c); 3045 /* Send extended data, i.e. stderr */ 3046 if (!(c->flags & CHAN_EOF_SENT) && 3047 c->extended_usage == CHAN_EXTENDED_READ) 3048 ret |= channel_output_poll_extended_read(ssh, c); 3049 } 3050 return ret; 3051 } 3052 3053 /* -- mux proxy support */ 3054 3055 /* 3056 * When multiplexing channel messages for mux clients we have to deal 3057 * with downstream messages from the mux client and upstream messages 3058 * from the ssh server: 3059 * 1) Handling downstream messages is straightforward and happens 3060 * in channel_proxy_downstream(): 3061 * - We forward all messages (mostly) unmodified to the server. 3062 * - However, in order to route messages from upstream to the correct 3063 * downstream client, we have to replace the channel IDs used by the 3064 * mux clients with a unique channel ID because the mux clients might 3065 * use conflicting channel IDs. 3066 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3067 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3068 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3069 * with the newly allocated channel ID. 3070 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3071 * channels and processed by channel_proxy_upstream(). The local channel ID 3072 * is then translated back to the original mux client ID. 3073 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3074 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3075 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3076 * downstream mux client are removed. 3077 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3078 * requires more work, because they are not addressed to a specific 3079 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3080 * out whether the request is addressed to the local client or a 3081 * specific downstream client based on the listen-address/port. 3082 * 6) Agent and X11-Forwarding have a similar problem and are currently 3083 * not supported as the matching session/channel cannot be identified 3084 * easily. 3085 */ 3086 3087 /* 3088 * receive packets from downstream mux clients: 3089 * channel callback fired on read from mux client, creates 3090 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3091 * on channel creation. 3092 */ 3093 int 3094 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3095 { 3096 Channel *c = NULL; 3097 struct sshbuf *original = NULL, *modified = NULL; 3098 const u_char *cp; 3099 char *ctype = NULL, *listen_host = NULL; 3100 u_char type; 3101 size_t have; 3102 int ret = -1, r; 3103 u_int id, remote_id, listen_port; 3104 3105 /* sshbuf_dump(downstream->input, stderr); */ 3106 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3107 != 0) { 3108 error_fr(r, "parse"); 3109 return -1; 3110 } 3111 if (have < 2) { 3112 error_f("short message"); 3113 return -1; 3114 } 3115 type = cp[1]; 3116 /* skip padlen + type */ 3117 cp += 2; 3118 have -= 2; 3119 if (ssh_packet_log_type(type)) 3120 debug3_f("channel %u: down->up: type %u", 3121 downstream->self, type); 3122 3123 switch (type) { 3124 case SSH2_MSG_CHANNEL_OPEN: 3125 if ((original = sshbuf_from(cp, have)) == NULL || 3126 (modified = sshbuf_new()) == NULL) { 3127 error_f("alloc"); 3128 goto out; 3129 } 3130 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3131 (r = sshbuf_get_u32(original, &id)) != 0) { 3132 error_fr(r, "parse"); 3133 goto out; 3134 } 3135 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3136 -1, -1, -1, 0, 0, 0, ctype, 1); 3137 c->mux_ctx = downstream; /* point to mux client */ 3138 c->mux_downstream_id = id; /* original downstream id */ 3139 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3140 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3141 (r = sshbuf_putb(modified, original)) != 0) { 3142 error_fr(r, "compose"); 3143 channel_free(ssh, c); 3144 goto out; 3145 } 3146 break; 3147 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3148 /* 3149 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3150 * need to parse 'remote_id' instead of 'ctype'. 3151 */ 3152 if ((original = sshbuf_from(cp, have)) == NULL || 3153 (modified = sshbuf_new()) == NULL) { 3154 error_f("alloc"); 3155 goto out; 3156 } 3157 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3158 (r = sshbuf_get_u32(original, &id)) != 0) { 3159 error_fr(r, "parse"); 3160 goto out; 3161 } 3162 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3163 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3164 c->mux_ctx = downstream; /* point to mux client */ 3165 c->mux_downstream_id = id; 3166 c->remote_id = remote_id; 3167 c->have_remote_id = 1; 3168 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3169 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3170 (r = sshbuf_putb(modified, original)) != 0) { 3171 error_fr(r, "compose"); 3172 channel_free(ssh, c); 3173 goto out; 3174 } 3175 break; 3176 case SSH2_MSG_GLOBAL_REQUEST: 3177 if ((original = sshbuf_from(cp, have)) == NULL) { 3178 error_f("alloc"); 3179 goto out; 3180 } 3181 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3182 error_fr(r, "parse"); 3183 goto out; 3184 } 3185 if (strcmp(ctype, "tcpip-forward") != 0) { 3186 error_f("unsupported request %s", ctype); 3187 goto out; 3188 } 3189 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3190 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3191 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3192 error_fr(r, "parse"); 3193 goto out; 3194 } 3195 if (listen_port > 65535) { 3196 error_f("tcpip-forward for %s: bad port %u", 3197 listen_host, listen_port); 3198 goto out; 3199 } 3200 /* Record that connection to this host/port is permitted. */ 3201 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", 3202 -1, listen_host, NULL, (int)listen_port, downstream); 3203 break; 3204 case SSH2_MSG_CHANNEL_CLOSE: 3205 if (have < 4) 3206 break; 3207 remote_id = PEEK_U32(cp); 3208 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3209 if (c->flags & CHAN_CLOSE_RCVD) 3210 channel_free(ssh, c); 3211 else 3212 c->flags |= CHAN_CLOSE_SENT; 3213 } 3214 break; 3215 } 3216 if (modified) { 3217 if ((r = sshpkt_start(ssh, type)) != 0 || 3218 (r = sshpkt_putb(ssh, modified)) != 0 || 3219 (r = sshpkt_send(ssh)) != 0) { 3220 error_fr(r, "send"); 3221 goto out; 3222 } 3223 } else { 3224 if ((r = sshpkt_start(ssh, type)) != 0 || 3225 (r = sshpkt_put(ssh, cp, have)) != 0 || 3226 (r = sshpkt_send(ssh)) != 0) { 3227 error_fr(r, "send"); 3228 goto out; 3229 } 3230 } 3231 ret = 0; 3232 out: 3233 free(ctype); 3234 free(listen_host); 3235 sshbuf_free(original); 3236 sshbuf_free(modified); 3237 return ret; 3238 } 3239 3240 /* 3241 * receive packets from upstream server and de-multiplex packets 3242 * to correct downstream: 3243 * implemented as a helper for channel input handlers, 3244 * replaces local (proxy) channel ID with downstream channel ID. 3245 */ 3246 int 3247 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3248 { 3249 struct sshbuf *b = NULL; 3250 Channel *downstream; 3251 const u_char *cp = NULL; 3252 size_t len; 3253 int r; 3254 3255 /* 3256 * When receiving packets from the peer we need to check whether we 3257 * need to forward the packets to the mux client. In this case we 3258 * restore the original channel id and keep track of CLOSE messages, 3259 * so we can cleanup the channel. 3260 */ 3261 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3262 return 0; 3263 if ((downstream = c->mux_ctx) == NULL) 3264 return 0; 3265 switch (type) { 3266 case SSH2_MSG_CHANNEL_CLOSE: 3267 case SSH2_MSG_CHANNEL_DATA: 3268 case SSH2_MSG_CHANNEL_EOF: 3269 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3270 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3271 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3272 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3273 case SSH2_MSG_CHANNEL_SUCCESS: 3274 case SSH2_MSG_CHANNEL_FAILURE: 3275 case SSH2_MSG_CHANNEL_REQUEST: 3276 break; 3277 default: 3278 debug2_f("channel %u: unsupported type %u", c->self, type); 3279 return 0; 3280 } 3281 if ((b = sshbuf_new()) == NULL) { 3282 error_f("alloc reply"); 3283 goto out; 3284 } 3285 /* get remaining payload (after id) */ 3286 cp = sshpkt_ptr(ssh, &len); 3287 if (cp == NULL) { 3288 error_f("no packet"); 3289 goto out; 3290 } 3291 /* translate id and send to muxclient */ 3292 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3293 (r = sshbuf_put_u8(b, type)) != 0 || 3294 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3295 (r = sshbuf_put(b, cp, len)) != 0 || 3296 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3297 error_fr(r, "compose muxclient"); 3298 goto out; 3299 } 3300 /* sshbuf_dump(b, stderr); */ 3301 if (ssh_packet_log_type(type)) 3302 debug3_f("channel %u: up->down: type %u", c->self, type); 3303 out: 3304 /* update state */ 3305 switch (type) { 3306 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3307 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3308 if (cp && len > 4) { 3309 c->remote_id = PEEK_U32(cp); 3310 c->have_remote_id = 1; 3311 } 3312 break; 3313 case SSH2_MSG_CHANNEL_CLOSE: 3314 if (c->flags & CHAN_CLOSE_SENT) 3315 channel_free(ssh, c); 3316 else 3317 c->flags |= CHAN_CLOSE_RCVD; 3318 break; 3319 } 3320 sshbuf_free(b); 3321 return 1; 3322 } 3323 3324 /* -- protocol input */ 3325 3326 /* Parse a channel ID from the current packet */ 3327 static int 3328 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3329 { 3330 u_int32_t id; 3331 int r; 3332 3333 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3334 error_r(r, "%s: parse id", where); 3335 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3336 } 3337 if (id > INT_MAX) { 3338 error_r(r, "%s: bad channel id %u", where, id); 3339 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3340 } 3341 return (int)id; 3342 } 3343 3344 /* Lookup a channel from an ID in the current packet */ 3345 static Channel * 3346 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3347 { 3348 int id = channel_parse_id(ssh, where, what); 3349 Channel *c; 3350 3351 if ((c = channel_lookup(ssh, id)) == NULL) { 3352 ssh_packet_disconnect(ssh, 3353 "%s packet referred to nonexistent channel %d", what, id); 3354 } 3355 return c; 3356 } 3357 3358 int 3359 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3360 { 3361 const u_char *data; 3362 size_t data_len, win_len; 3363 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3364 int r; 3365 3366 if (channel_proxy_upstream(c, type, seq, ssh)) 3367 return 0; 3368 3369 /* Ignore any data for non-open channels (might happen on close) */ 3370 if (c->type != SSH_CHANNEL_OPEN && 3371 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3372 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3373 c->type != SSH_CHANNEL_X11_OPEN) 3374 return 0; 3375 3376 /* Get the data. */ 3377 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3378 (r = sshpkt_get_end(ssh)) != 0) 3379 fatal_fr(r, "channel %i: get data", c->self); 3380 3381 win_len = data_len; 3382 if (c->datagram) 3383 win_len += 4; /* string length header */ 3384 3385 /* 3386 * The sending side reduces its window as it sends data, so we 3387 * must 'fake' consumption of the data in order to ensure that window 3388 * updates are sent back. Otherwise the connection might deadlock. 3389 */ 3390 if (c->ostate != CHAN_OUTPUT_OPEN) { 3391 c->local_window -= win_len; 3392 c->local_consumed += win_len; 3393 return 0; 3394 } 3395 3396 if (win_len > c->local_maxpacket) { 3397 logit("channel %d: rcvd big packet %zu, maxpack %u", 3398 c->self, win_len, c->local_maxpacket); 3399 return 0; 3400 } 3401 if (win_len > c->local_window) { 3402 c->local_window_exceeded += win_len - c->local_window; 3403 logit("channel %d: rcvd too much data %zu, win %u/%u " 3404 "(excess %u)", c->self, win_len, c->local_window, 3405 c->local_window_max, c->local_window_exceeded); 3406 c->local_window = 0; 3407 /* Allow 10% grace before bringing the hammer down */ 3408 if (c->local_window_exceeded > (c->local_window_max / 10)) { 3409 ssh_packet_disconnect(ssh, "channel %d: peer ignored " 3410 "channel window", c->self); 3411 } 3412 } else { 3413 c->local_window -= win_len; 3414 c->local_window_exceeded = 0; 3415 } 3416 3417 if (c->datagram) { 3418 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3419 fatal_fr(r, "channel %i: append datagram", c->self); 3420 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3421 fatal_fr(r, "channel %i: append data", c->self); 3422 3423 return 0; 3424 } 3425 3426 int 3427 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3428 { 3429 const u_char *data; 3430 size_t data_len; 3431 u_int32_t tcode; 3432 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3433 int r; 3434 3435 if (channel_proxy_upstream(c, type, seq, ssh)) 3436 return 0; 3437 if (c->type != SSH_CHANNEL_OPEN) { 3438 logit("channel %d: ext data for non open", c->self); 3439 return 0; 3440 } 3441 if (c->flags & CHAN_EOF_RCVD) { 3442 if (ssh->compat & SSH_BUG_EXTEOF) 3443 debug("channel %d: accepting ext data after eof", 3444 c->self); 3445 else 3446 ssh_packet_disconnect(ssh, "Received extended_data " 3447 "after EOF on channel %d.", c->self); 3448 } 3449 3450 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3451 error_fr(r, "parse tcode"); 3452 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3453 } 3454 if (c->efd == -1 || 3455 c->extended_usage != CHAN_EXTENDED_WRITE || 3456 tcode != SSH2_EXTENDED_DATA_STDERR) { 3457 logit("channel %d: bad ext data", c->self); 3458 return 0; 3459 } 3460 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3461 (r = sshpkt_get_end(ssh)) != 0) { 3462 error_fr(r, "parse data"); 3463 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3464 } 3465 3466 if (data_len > c->local_window) { 3467 logit("channel %d: rcvd too much extended_data %zu, win %u", 3468 c->self, data_len, c->local_window); 3469 return 0; 3470 } 3471 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3472 /* XXX sshpkt_getb? */ 3473 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3474 error_fr(r, "append"); 3475 c->local_window -= data_len; 3476 return 0; 3477 } 3478 3479 int 3480 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3481 { 3482 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3483 int r; 3484 3485 if ((r = sshpkt_get_end(ssh)) != 0) { 3486 error_fr(r, "parse data"); 3487 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3488 } 3489 3490 if (channel_proxy_upstream(c, type, seq, ssh)) 3491 return 0; 3492 chan_rcvd_ieof(ssh, c); 3493 3494 /* XXX force input close */ 3495 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3496 debug("channel %d: FORCE input drain", c->self); 3497 c->istate = CHAN_INPUT_WAIT_DRAIN; 3498 if (sshbuf_len(c->input) == 0) 3499 chan_ibuf_empty(ssh, c); 3500 } 3501 return 0; 3502 } 3503 3504 int 3505 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3506 { 3507 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3508 int r; 3509 3510 if (channel_proxy_upstream(c, type, seq, ssh)) 3511 return 0; 3512 if ((r = sshpkt_get_end(ssh)) != 0) { 3513 error_fr(r, "parse data"); 3514 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3515 } 3516 chan_rcvd_oclose(ssh, c); 3517 return 0; 3518 } 3519 3520 int 3521 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3522 { 3523 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3524 u_int32_t remote_window, remote_maxpacket; 3525 int r; 3526 3527 if (channel_proxy_upstream(c, type, seq, ssh)) 3528 return 0; 3529 if (c->type != SSH_CHANNEL_OPENING) 3530 ssh_packet_disconnect(ssh, "Received open confirmation for " 3531 "non-opening channel %d.", c->self); 3532 /* 3533 * Record the remote channel number and mark that the channel 3534 * is now open. 3535 */ 3536 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3537 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3538 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3539 (r = sshpkt_get_end(ssh)) != 0) { 3540 error_fr(r, "window/maxpacket"); 3541 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3542 } 3543 3544 c->have_remote_id = 1; 3545 c->remote_window = remote_window; 3546 c->remote_maxpacket = remote_maxpacket; 3547 c->type = SSH_CHANNEL_OPEN; 3548 if (c->open_confirm) { 3549 debug2_f("channel %d: callback start", c->self); 3550 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3551 debug2_f("channel %d: callback done", c->self); 3552 } 3553 channel_set_used_time(ssh, c); 3554 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3555 c->remote_window, c->remote_maxpacket); 3556 return 0; 3557 } 3558 3559 static char * 3560 reason2txt(int reason) 3561 { 3562 switch (reason) { 3563 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3564 return "administratively prohibited"; 3565 case SSH2_OPEN_CONNECT_FAILED: 3566 return "connect failed"; 3567 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3568 return "unknown channel type"; 3569 case SSH2_OPEN_RESOURCE_SHORTAGE: 3570 return "resource shortage"; 3571 } 3572 return "unknown reason"; 3573 } 3574 3575 int 3576 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3577 { 3578 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3579 u_int32_t reason; 3580 char *msg = NULL; 3581 int r; 3582 3583 if (channel_proxy_upstream(c, type, seq, ssh)) 3584 return 0; 3585 if (c->type != SSH_CHANNEL_OPENING) 3586 ssh_packet_disconnect(ssh, "Received open failure for " 3587 "non-opening channel %d.", c->self); 3588 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3589 error_fr(r, "parse reason"); 3590 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3591 } 3592 /* skip language */ 3593 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3594 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3595 (r = sshpkt_get_end(ssh)) != 0) { 3596 error_fr(r, "parse msg/lang"); 3597 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3598 } 3599 logit("channel %d: open failed: %s%s%s", c->self, 3600 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3601 free(msg); 3602 if (c->open_confirm) { 3603 debug2_f("channel %d: callback start", c->self); 3604 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3605 debug2_f("channel %d: callback done", c->self); 3606 } 3607 /* Schedule the channel for cleanup/deletion. */ 3608 chan_mark_dead(ssh, c); 3609 return 0; 3610 } 3611 3612 int 3613 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3614 { 3615 int id = channel_parse_id(ssh, __func__, "window adjust"); 3616 Channel *c; 3617 u_int32_t adjust; 3618 u_int new_rwin; 3619 int r; 3620 3621 if ((c = channel_lookup(ssh, id)) == NULL) { 3622 logit("Received window adjust for non-open channel %d.", id); 3623 return 0; 3624 } 3625 3626 if (channel_proxy_upstream(c, type, seq, ssh)) 3627 return 0; 3628 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3629 (r = sshpkt_get_end(ssh)) != 0) { 3630 error_fr(r, "parse adjust"); 3631 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3632 } 3633 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3634 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3635 fatal("channel %d: adjust %u overflows remote window %u", 3636 c->self, adjust, c->remote_window); 3637 } 3638 c->remote_window = new_rwin; 3639 return 0; 3640 } 3641 3642 int 3643 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3644 { 3645 int id = channel_parse_id(ssh, __func__, "status confirm"); 3646 Channel *c; 3647 struct channel_confirm *cc; 3648 3649 /* Reset keepalive timeout */ 3650 ssh_packet_set_alive_timeouts(ssh, 0); 3651 3652 debug2_f("type %d id %d", type, id); 3653 3654 if ((c = channel_lookup(ssh, id)) == NULL) { 3655 logit_f("%d: unknown", id); 3656 return 0; 3657 } 3658 if (channel_proxy_upstream(c, type, seq, ssh)) 3659 return 0; 3660 if (sshpkt_get_end(ssh) != 0) 3661 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3662 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3663 return 0; 3664 cc->cb(ssh, type, c, cc->ctx); 3665 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3666 freezero(cc, sizeof(*cc)); 3667 return 0; 3668 } 3669 3670 /* -- tcp forwarding */ 3671 3672 void 3673 channel_set_af(struct ssh *ssh, int af) 3674 { 3675 ssh->chanctxt->IPv4or6 = af; 3676 } 3677 3678 3679 /* 3680 * Determine whether or not a port forward listens to loopback, the 3681 * specified address or wildcard. On the client, a specified bind 3682 * address will always override gateway_ports. On the server, a 3683 * gateway_ports of 1 (``yes'') will override the client's specification 3684 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3685 * will bind to whatever address the client asked for. 3686 * 3687 * Special-case listen_addrs are: 3688 * 3689 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3690 * "" (empty string), "*" -> wildcard v4/v6 3691 * "localhost" -> loopback v4/v6 3692 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3693 */ 3694 static const char * 3695 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3696 int is_client, struct ForwardOptions *fwd_opts) 3697 { 3698 const char *addr = NULL; 3699 int wildcard = 0; 3700 3701 if (listen_addr == NULL) { 3702 /* No address specified: default to gateway_ports setting */ 3703 if (fwd_opts->gateway_ports) 3704 wildcard = 1; 3705 } else if (fwd_opts->gateway_ports || is_client) { 3706 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3707 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3708 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3709 (!is_client && fwd_opts->gateway_ports == 1)) { 3710 wildcard = 1; 3711 /* 3712 * Notify client if they requested a specific listen 3713 * address and it was overridden. 3714 */ 3715 if (*listen_addr != '\0' && 3716 strcmp(listen_addr, "0.0.0.0") != 0 && 3717 strcmp(listen_addr, "*") != 0) { 3718 ssh_packet_send_debug(ssh, 3719 "Forwarding listen address " 3720 "\"%s\" overridden by server " 3721 "GatewayPorts", listen_addr); 3722 } 3723 } else if (strcmp(listen_addr, "localhost") != 0 || 3724 strcmp(listen_addr, "127.0.0.1") == 0 || 3725 strcmp(listen_addr, "::1") == 0) { 3726 /* 3727 * Accept explicit localhost address when 3728 * GatewayPorts=yes. The "localhost" hostname is 3729 * deliberately skipped here so it will listen on all 3730 * available local address families. 3731 */ 3732 addr = listen_addr; 3733 } 3734 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3735 strcmp(listen_addr, "::1") == 0) { 3736 /* 3737 * If a specific IPv4/IPv6 localhost address has been 3738 * requested then accept it even if gateway_ports is in 3739 * effect. This allows the client to prefer IPv4 or IPv6. 3740 */ 3741 addr = listen_addr; 3742 } 3743 if (wildcardp != NULL) 3744 *wildcardp = wildcard; 3745 return addr; 3746 } 3747 3748 static int 3749 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3750 struct Forward *fwd, int *allocated_listen_port, 3751 struct ForwardOptions *fwd_opts) 3752 { 3753 Channel *c; 3754 int sock, r, success = 0, wildcard = 0, is_client; 3755 struct addrinfo hints, *ai, *aitop; 3756 const char *host, *addr; 3757 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3758 in_port_t *lport_p; 3759 3760 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3761 3762 if (is_client && fwd->connect_path != NULL) { 3763 host = fwd->connect_path; 3764 } else { 3765 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3766 fwd->listen_host : fwd->connect_host; 3767 if (host == NULL) { 3768 error("No forward host name."); 3769 return 0; 3770 } 3771 if (strlen(host) >= NI_MAXHOST) { 3772 error("Forward host name too long."); 3773 return 0; 3774 } 3775 } 3776 3777 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3778 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3779 is_client, fwd_opts); 3780 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3781 (addr == NULL) ? "NULL" : addr); 3782 3783 /* 3784 * getaddrinfo returns a loopback address if the hostname is 3785 * set to NULL and hints.ai_flags is not AI_PASSIVE 3786 */ 3787 memset(&hints, 0, sizeof(hints)); 3788 hints.ai_family = ssh->chanctxt->IPv4or6; 3789 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3790 hints.ai_socktype = SOCK_STREAM; 3791 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3792 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3793 if (addr == NULL) { 3794 /* This really shouldn't happen */ 3795 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3796 ssh_gai_strerror(r)); 3797 } else { 3798 error_f("getaddrinfo(%.64s): %s", addr, 3799 ssh_gai_strerror(r)); 3800 } 3801 return 0; 3802 } 3803 if (allocated_listen_port != NULL) 3804 *allocated_listen_port = 0; 3805 for (ai = aitop; ai; ai = ai->ai_next) { 3806 switch (ai->ai_family) { 3807 case AF_INET: 3808 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3809 sin_port; 3810 break; 3811 case AF_INET6: 3812 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3813 sin6_port; 3814 break; 3815 default: 3816 continue; 3817 } 3818 /* 3819 * If allocating a port for -R forwards, then use the 3820 * same port for all address families. 3821 */ 3822 if (type == SSH_CHANNEL_RPORT_LISTENER && 3823 fwd->listen_port == 0 && allocated_listen_port != NULL && 3824 *allocated_listen_port > 0) 3825 *lport_p = htons(*allocated_listen_port); 3826 3827 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3828 strport, sizeof(strport), 3829 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3830 error_f("getnameinfo failed"); 3831 continue; 3832 } 3833 /* Create a port to listen for the host. */ 3834 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3835 if (sock == -1) { 3836 /* this is no error since kernel may not support ipv6 */ 3837 verbose("socket [%s]:%s: %.100s", ntop, strport, 3838 strerror(errno)); 3839 continue; 3840 } 3841 3842 set_reuseaddr(sock); 3843 3844 debug("Local forwarding listening on %s port %s.", 3845 ntop, strport); 3846 3847 /* Bind the socket to the address. */ 3848 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3849 /* 3850 * address can be in if use ipv6 address is 3851 * already bound 3852 */ 3853 verbose("bind [%s]:%s: %.100s", 3854 ntop, strport, strerror(errno)); 3855 close(sock); 3856 continue; 3857 } 3858 /* Start listening for connections on the socket. */ 3859 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3860 error("listen [%s]:%s: %.100s", ntop, strport, 3861 strerror(errno)); 3862 close(sock); 3863 continue; 3864 } 3865 3866 /* 3867 * fwd->listen_port == 0 requests a dynamically allocated port - 3868 * record what we got. 3869 */ 3870 if (type == SSH_CHANNEL_RPORT_LISTENER && 3871 fwd->listen_port == 0 && 3872 allocated_listen_port != NULL && 3873 *allocated_listen_port == 0) { 3874 *allocated_listen_port = get_local_port(sock); 3875 debug("Allocated listen port %d", 3876 *allocated_listen_port); 3877 } 3878 3879 /* Allocate a channel number for the socket. */ 3880 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3881 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3882 0, "port listener", 1); 3883 c->path = xstrdup(host); 3884 c->host_port = fwd->connect_port; 3885 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3886 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3887 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3888 c->listening_port = *allocated_listen_port; 3889 else 3890 c->listening_port = fwd->listen_port; 3891 success = 1; 3892 } 3893 if (success == 0) 3894 error_f("cannot listen to port: %d", fwd->listen_port); 3895 freeaddrinfo(aitop); 3896 return success; 3897 } 3898 3899 static int 3900 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3901 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3902 { 3903 struct sockaddr_un sunaddr; 3904 const char *path; 3905 Channel *c; 3906 int port, sock; 3907 mode_t omask; 3908 3909 switch (type) { 3910 case SSH_CHANNEL_UNIX_LISTENER: 3911 if (fwd->connect_path != NULL) { 3912 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3913 error("Local connecting path too long: %s", 3914 fwd->connect_path); 3915 return 0; 3916 } 3917 path = fwd->connect_path; 3918 port = PORT_STREAMLOCAL; 3919 } else { 3920 if (fwd->connect_host == NULL) { 3921 error("No forward host name."); 3922 return 0; 3923 } 3924 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3925 error("Forward host name too long."); 3926 return 0; 3927 } 3928 path = fwd->connect_host; 3929 port = fwd->connect_port; 3930 } 3931 break; 3932 case SSH_CHANNEL_RUNIX_LISTENER: 3933 path = fwd->listen_path; 3934 port = PORT_STREAMLOCAL; 3935 break; 3936 default: 3937 error_f("unexpected channel type %d", type); 3938 return 0; 3939 } 3940 3941 if (fwd->listen_path == NULL) { 3942 error("No forward path name."); 3943 return 0; 3944 } 3945 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3946 error("Local listening path too long: %s", fwd->listen_path); 3947 return 0; 3948 } 3949 3950 debug3_f("type %d path %s", type, fwd->listen_path); 3951 3952 /* Start a Unix domain listener. */ 3953 omask = umask(fwd_opts->streamlocal_bind_mask); 3954 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3955 fwd_opts->streamlocal_bind_unlink); 3956 umask(omask); 3957 if (sock < 0) 3958 return 0; 3959 3960 debug("Local forwarding listening on path %s.", fwd->listen_path); 3961 3962 /* Allocate a channel number for the socket. */ 3963 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 3964 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3965 0, "unix listener", 1); 3966 c->path = xstrdup(path); 3967 c->host_port = port; 3968 c->listening_port = PORT_STREAMLOCAL; 3969 c->listening_addr = xstrdup(fwd->listen_path); 3970 return 1; 3971 } 3972 3973 static int 3974 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3975 const char *host, u_short port) 3976 { 3977 u_int i; 3978 int found = 0; 3979 3980 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3981 Channel *c = ssh->chanctxt->channels[i]; 3982 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3983 continue; 3984 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3985 debug2_f("close channel %d", i); 3986 channel_free(ssh, c); 3987 found = 1; 3988 } 3989 } 3990 3991 return found; 3992 } 3993 3994 static int 3995 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3996 { 3997 u_int i; 3998 int found = 0; 3999 4000 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4001 Channel *c = ssh->chanctxt->channels[i]; 4002 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 4003 continue; 4004 if (c->path == NULL) 4005 continue; 4006 if (strcmp(c->path, path) == 0) { 4007 debug2_f("close channel %d", i); 4008 channel_free(ssh, c); 4009 found = 1; 4010 } 4011 } 4012 4013 return found; 4014 } 4015 4016 int 4017 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4018 { 4019 if (fwd->listen_path != NULL) { 4020 return channel_cancel_rport_listener_streamlocal(ssh, 4021 fwd->listen_path); 4022 } else { 4023 return channel_cancel_rport_listener_tcpip(ssh, 4024 fwd->listen_host, fwd->listen_port); 4025 } 4026 } 4027 4028 static int 4029 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4030 const char *lhost, u_short lport, int cport, 4031 struct ForwardOptions *fwd_opts) 4032 { 4033 u_int i; 4034 int found = 0; 4035 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4036 4037 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4038 Channel *c = ssh->chanctxt->channels[i]; 4039 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4040 continue; 4041 if (c->listening_port != lport) 4042 continue; 4043 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4044 /* skip dynamic forwardings */ 4045 if (c->host_port == 0) 4046 continue; 4047 } else { 4048 if (c->host_port != cport) 4049 continue; 4050 } 4051 if ((c->listening_addr == NULL && addr != NULL) || 4052 (c->listening_addr != NULL && addr == NULL)) 4053 continue; 4054 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4055 debug2_f("close channel %d", i); 4056 channel_free(ssh, c); 4057 found = 1; 4058 } 4059 } 4060 4061 return found; 4062 } 4063 4064 static int 4065 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4066 { 4067 u_int i; 4068 int found = 0; 4069 4070 if (path == NULL) { 4071 error_f("no path specified."); 4072 return 0; 4073 } 4074 4075 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4076 Channel *c = ssh->chanctxt->channels[i]; 4077 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4078 continue; 4079 if (c->listening_addr == NULL) 4080 continue; 4081 if (strcmp(c->listening_addr, path) == 0) { 4082 debug2_f("close channel %d", i); 4083 channel_free(ssh, c); 4084 found = 1; 4085 } 4086 } 4087 4088 return found; 4089 } 4090 4091 int 4092 channel_cancel_lport_listener(struct ssh *ssh, 4093 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4094 { 4095 if (fwd->listen_path != NULL) { 4096 return channel_cancel_lport_listener_streamlocal(ssh, 4097 fwd->listen_path); 4098 } else { 4099 return channel_cancel_lport_listener_tcpip(ssh, 4100 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4101 } 4102 } 4103 4104 /* protocol local port fwd, used by ssh */ 4105 int 4106 channel_setup_local_fwd_listener(struct ssh *ssh, 4107 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4108 { 4109 if (fwd->listen_path != NULL) { 4110 return channel_setup_fwd_listener_streamlocal(ssh, 4111 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4112 } else { 4113 return channel_setup_fwd_listener_tcpip(ssh, 4114 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4115 } 4116 } 4117 4118 /* Matches a remote forwarding permission against a requested forwarding */ 4119 static int 4120 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4121 { 4122 int ret; 4123 char *lhost; 4124 4125 /* XXX add ACLs for streamlocal */ 4126 if (fwd->listen_path != NULL) 4127 return 1; 4128 4129 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4130 return 0; 4131 4132 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4133 allowed_open->listen_port != fwd->listen_port) 4134 return 0; 4135 4136 /* Match hostnames case-insensitively */ 4137 lhost = xstrdup(fwd->listen_host); 4138 lowercase(lhost); 4139 ret = match_pattern(lhost, allowed_open->listen_host); 4140 free(lhost); 4141 4142 return ret; 4143 } 4144 4145 /* Checks whether a requested remote forwarding is permitted */ 4146 static int 4147 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4148 { 4149 struct ssh_channels *sc = ssh->chanctxt; 4150 struct permission_set *pset = &sc->remote_perms; 4151 u_int i, permit, permit_adm = 1; 4152 struct permission *perm; 4153 4154 /* XXX apply GatewayPorts override before checking? */ 4155 4156 permit = pset->all_permitted; 4157 if (!permit) { 4158 for (i = 0; i < pset->num_permitted_user; i++) { 4159 perm = &pset->permitted_user[i]; 4160 if (remote_open_match(perm, fwd)) { 4161 permit = 1; 4162 break; 4163 } 4164 } 4165 } 4166 4167 if (pset->num_permitted_admin > 0) { 4168 permit_adm = 0; 4169 for (i = 0; i < pset->num_permitted_admin; i++) { 4170 perm = &pset->permitted_admin[i]; 4171 if (remote_open_match(perm, fwd)) { 4172 permit_adm = 1; 4173 break; 4174 } 4175 } 4176 } 4177 4178 return permit && permit_adm; 4179 } 4180 4181 /* protocol v2 remote port fwd, used by sshd */ 4182 int 4183 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4184 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4185 { 4186 if (!check_rfwd_permission(ssh, fwd)) { 4187 ssh_packet_send_debug(ssh, "port forwarding refused"); 4188 if (fwd->listen_path != NULL) 4189 /* XXX always allowed, see remote_open_match() */ 4190 logit("Received request from %.100s port %d to " 4191 "remote forward to path \"%.100s\", " 4192 "but the request was denied.", 4193 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4194 fwd->listen_path); 4195 else if(fwd->listen_host != NULL) 4196 logit("Received request from %.100s port %d to " 4197 "remote forward to host %.100s port %d, " 4198 "but the request was denied.", 4199 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4200 fwd->listen_host, fwd->listen_port ); 4201 else 4202 logit("Received request from %.100s port %d to remote " 4203 "forward, but the request was denied.", 4204 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4205 return 0; 4206 } 4207 if (fwd->listen_path != NULL) { 4208 return channel_setup_fwd_listener_streamlocal(ssh, 4209 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4210 } else { 4211 return channel_setup_fwd_listener_tcpip(ssh, 4212 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4213 fwd_opts); 4214 } 4215 } 4216 4217 /* 4218 * Translate the requested rfwd listen host to something usable for 4219 * this server. 4220 */ 4221 static const char * 4222 channel_rfwd_bind_host(const char *listen_host) 4223 { 4224 if (listen_host == NULL) { 4225 return "localhost"; 4226 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4227 return ""; 4228 } else 4229 return listen_host; 4230 } 4231 4232 /* 4233 * Initiate forwarding of connections to port "port" on remote host through 4234 * the secure channel to host:port from local side. 4235 * Returns handle (index) for updating the dynamic listen port with 4236 * channel_update_permission(). 4237 */ 4238 int 4239 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4240 { 4241 int r, success = 0, idx = -1; 4242 const char *host_to_connect, *listen_host, *listen_path; 4243 int port_to_connect, listen_port; 4244 4245 /* Send the forward request to the remote side. */ 4246 if (fwd->listen_path != NULL) { 4247 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4248 (r = sshpkt_put_cstring(ssh, 4249 "streamlocal-forward@openssh.com")) != 0 || 4250 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4251 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4252 (r = sshpkt_send(ssh)) != 0 || 4253 (r = ssh_packet_write_wait(ssh)) != 0) 4254 fatal_fr(r, "request streamlocal"); 4255 } else { 4256 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4257 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4258 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4259 (r = sshpkt_put_cstring(ssh, 4260 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4261 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4262 (r = sshpkt_send(ssh)) != 0 || 4263 (r = ssh_packet_write_wait(ssh)) != 0) 4264 fatal_fr(r, "request tcpip-forward"); 4265 } 4266 /* Assume that server accepts the request */ 4267 success = 1; 4268 if (success) { 4269 /* Record that connection to this host/port is permitted. */ 4270 host_to_connect = listen_host = listen_path = NULL; 4271 port_to_connect = listen_port = 0; 4272 if (fwd->connect_path != NULL) { 4273 host_to_connect = fwd->connect_path; 4274 port_to_connect = PORT_STREAMLOCAL; 4275 } else { 4276 host_to_connect = fwd->connect_host; 4277 port_to_connect = fwd->connect_port; 4278 } 4279 if (fwd->listen_path != NULL) { 4280 listen_path = fwd->listen_path; 4281 listen_port = PORT_STREAMLOCAL; 4282 } else { 4283 listen_host = fwd->listen_host; 4284 listen_port = fwd->listen_port; 4285 } 4286 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4287 host_to_connect, port_to_connect, 4288 listen_host, listen_path, listen_port, NULL); 4289 } 4290 return idx; 4291 } 4292 4293 static int 4294 open_match(struct permission *allowed_open, const char *requestedhost, 4295 int requestedport) 4296 { 4297 if (allowed_open->host_to_connect == NULL) 4298 return 0; 4299 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4300 allowed_open->port_to_connect != requestedport) 4301 return 0; 4302 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4303 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4304 return 0; 4305 return 1; 4306 } 4307 4308 /* 4309 * Note that in the listen host/port case 4310 * we don't support FWD_PERMIT_ANY_PORT and 4311 * need to translate between the configured-host (listen_host) 4312 * and what we've sent to the remote server (channel_rfwd_bind_host) 4313 */ 4314 static int 4315 open_listen_match_tcpip(struct permission *allowed_open, 4316 const char *requestedhost, u_short requestedport, int translate) 4317 { 4318 const char *allowed_host; 4319 4320 if (allowed_open->host_to_connect == NULL) 4321 return 0; 4322 if (allowed_open->listen_port != requestedport) 4323 return 0; 4324 if (!translate && allowed_open->listen_host == NULL && 4325 requestedhost == NULL) 4326 return 1; 4327 allowed_host = translate ? 4328 channel_rfwd_bind_host(allowed_open->listen_host) : 4329 allowed_open->listen_host; 4330 if (allowed_host == NULL || requestedhost == NULL || 4331 strcmp(allowed_host, requestedhost) != 0) 4332 return 0; 4333 return 1; 4334 } 4335 4336 static int 4337 open_listen_match_streamlocal(struct permission *allowed_open, 4338 const char *requestedpath) 4339 { 4340 if (allowed_open->host_to_connect == NULL) 4341 return 0; 4342 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4343 return 0; 4344 if (allowed_open->listen_path == NULL || 4345 strcmp(allowed_open->listen_path, requestedpath) != 0) 4346 return 0; 4347 return 1; 4348 } 4349 4350 /* 4351 * Request cancellation of remote forwarding of connection host:port from 4352 * local side. 4353 */ 4354 static int 4355 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4356 const char *host, u_short port) 4357 { 4358 struct ssh_channels *sc = ssh->chanctxt; 4359 struct permission_set *pset = &sc->local_perms; 4360 int r; 4361 u_int i; 4362 struct permission *perm = NULL; 4363 4364 for (i = 0; i < pset->num_permitted_user; i++) { 4365 perm = &pset->permitted_user[i]; 4366 if (open_listen_match_tcpip(perm, host, port, 0)) 4367 break; 4368 perm = NULL; 4369 } 4370 if (perm == NULL) { 4371 debug_f("requested forward not found"); 4372 return -1; 4373 } 4374 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4375 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4376 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4377 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4378 (r = sshpkt_put_u32(ssh, port)) != 0 || 4379 (r = sshpkt_send(ssh)) != 0) 4380 fatal_fr(r, "send cancel"); 4381 4382 fwd_perm_clear(perm); /* unregister */ 4383 4384 return 0; 4385 } 4386 4387 /* 4388 * Request cancellation of remote forwarding of Unix domain socket 4389 * path from local side. 4390 */ 4391 static int 4392 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4393 { 4394 struct ssh_channels *sc = ssh->chanctxt; 4395 struct permission_set *pset = &sc->local_perms; 4396 int r; 4397 u_int i; 4398 struct permission *perm = NULL; 4399 4400 for (i = 0; i < pset->num_permitted_user; i++) { 4401 perm = &pset->permitted_user[i]; 4402 if (open_listen_match_streamlocal(perm, path)) 4403 break; 4404 perm = NULL; 4405 } 4406 if (perm == NULL) { 4407 debug_f("requested forward not found"); 4408 return -1; 4409 } 4410 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4411 (r = sshpkt_put_cstring(ssh, 4412 "cancel-streamlocal-forward@openssh.com")) != 0 || 4413 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4414 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4415 (r = sshpkt_send(ssh)) != 0) 4416 fatal_fr(r, "send cancel"); 4417 4418 fwd_perm_clear(perm); /* unregister */ 4419 4420 return 0; 4421 } 4422 4423 /* 4424 * Request cancellation of remote forwarding of a connection from local side. 4425 */ 4426 int 4427 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4428 { 4429 if (fwd->listen_path != NULL) { 4430 return channel_request_rforward_cancel_streamlocal(ssh, 4431 fwd->listen_path); 4432 } else { 4433 return channel_request_rforward_cancel_tcpip(ssh, 4434 fwd->listen_host, 4435 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4436 } 4437 } 4438 4439 /* 4440 * Permits opening to any host/port if permitted_user[] is empty. This is 4441 * usually called by the server, because the user could connect to any port 4442 * anyway, and the server has no way to know but to trust the client anyway. 4443 */ 4444 void 4445 channel_permit_all(struct ssh *ssh, int where) 4446 { 4447 struct permission_set *pset = permission_set_get(ssh, where); 4448 4449 if (pset->num_permitted_user == 0) 4450 pset->all_permitted = 1; 4451 } 4452 4453 /* 4454 * Permit the specified host/port for forwarding. 4455 */ 4456 void 4457 channel_add_permission(struct ssh *ssh, int who, int where, 4458 char *host, int port) 4459 { 4460 int local = where == FORWARD_LOCAL; 4461 struct permission_set *pset = permission_set_get(ssh, where); 4462 4463 debug("allow %s forwarding to host %s port %d", 4464 fwd_ident(who, where), host, port); 4465 /* 4466 * Remote forwards set listen_host/port, local forwards set 4467 * host/port_to_connect. 4468 */ 4469 permission_set_add(ssh, who, where, 4470 local ? host : 0, local ? port : 0, 4471 local ? NULL : host, NULL, local ? 0 : port, NULL); 4472 pset->all_permitted = 0; 4473 } 4474 4475 /* 4476 * Administratively disable forwarding. 4477 */ 4478 void 4479 channel_disable_admin(struct ssh *ssh, int where) 4480 { 4481 channel_clear_permission(ssh, FORWARD_ADM, where); 4482 permission_set_add(ssh, FORWARD_ADM, where, 4483 NULL, 0, NULL, NULL, 0, NULL); 4484 } 4485 4486 /* 4487 * Clear a list of permitted opens. 4488 */ 4489 void 4490 channel_clear_permission(struct ssh *ssh, int who, int where) 4491 { 4492 struct permission **permp; 4493 u_int *npermp; 4494 4495 permission_set_get_array(ssh, who, where, &permp, &npermp); 4496 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4497 *npermp = 0; 4498 } 4499 4500 /* 4501 * Update the listen port for a dynamic remote forward, after 4502 * the actual 'newport' has been allocated. If 'newport' < 0 is 4503 * passed then they entry will be invalidated. 4504 */ 4505 void 4506 channel_update_permission(struct ssh *ssh, int idx, int newport) 4507 { 4508 struct permission_set *pset = &ssh->chanctxt->local_perms; 4509 4510 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4511 debug_f("index out of range: %d num_permitted_user %d", 4512 idx, pset->num_permitted_user); 4513 return; 4514 } 4515 debug("%s allowed port %d for forwarding to host %s port %d", 4516 newport > 0 ? "Updating" : "Removing", 4517 newport, 4518 pset->permitted_user[idx].host_to_connect, 4519 pset->permitted_user[idx].port_to_connect); 4520 if (newport <= 0) 4521 fwd_perm_clear(&pset->permitted_user[idx]); 4522 else { 4523 pset->permitted_user[idx].listen_port = 4524 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4525 } 4526 } 4527 4528 /* Try to start non-blocking connect to next host in cctx list */ 4529 static int 4530 connect_next(struct channel_connect *cctx) 4531 { 4532 int sock, saved_errno; 4533 struct sockaddr_un *sunaddr; 4534 char ntop[NI_MAXHOST]; 4535 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4536 4537 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4538 switch (cctx->ai->ai_family) { 4539 case AF_UNIX: 4540 /* unix:pathname instead of host:port */ 4541 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4542 strlcpy(ntop, "unix", sizeof(ntop)); 4543 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4544 break; 4545 case AF_INET: 4546 case AF_INET6: 4547 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4548 ntop, sizeof(ntop), strport, sizeof(strport), 4549 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4550 error_f("getnameinfo failed"); 4551 continue; 4552 } 4553 break; 4554 default: 4555 continue; 4556 } 4557 debug_f("start for host %.100s ([%.100s]:%s)", 4558 cctx->host, ntop, strport); 4559 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4560 cctx->ai->ai_protocol)) == -1) { 4561 if (cctx->ai->ai_next == NULL) 4562 error("socket: %.100s", strerror(errno)); 4563 else 4564 verbose("socket: %.100s", strerror(errno)); 4565 continue; 4566 } 4567 if (set_nonblock(sock) == -1) 4568 fatal_f("set_nonblock(%d)", sock); 4569 if (connect(sock, cctx->ai->ai_addr, 4570 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4571 debug_f("host %.100s ([%.100s]:%s): %.100s", 4572 cctx->host, ntop, strport, strerror(errno)); 4573 saved_errno = errno; 4574 close(sock); 4575 errno = saved_errno; 4576 continue; /* fail -- try next */ 4577 } 4578 if (cctx->ai->ai_family != AF_UNIX) 4579 set_nodelay(sock); 4580 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4581 cctx->host, ntop, strport, sock); 4582 cctx->ai = cctx->ai->ai_next; 4583 return sock; 4584 } 4585 return -1; 4586 } 4587 4588 static void 4589 channel_connect_ctx_free(struct channel_connect *cctx) 4590 { 4591 free(cctx->host); 4592 if (cctx->aitop) { 4593 if (cctx->aitop->ai_family == AF_UNIX) 4594 free(cctx->aitop); 4595 else 4596 freeaddrinfo(cctx->aitop); 4597 } 4598 memset(cctx, 0, sizeof(*cctx)); 4599 } 4600 4601 /* 4602 * Return connecting socket to remote host:port or local socket path, 4603 * passing back the failure reason if appropriate. 4604 */ 4605 static int 4606 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4607 char *ctype, char *rname, struct channel_connect *cctx, 4608 int *reason, const char **errmsg) 4609 { 4610 struct addrinfo hints; 4611 int gaierr; 4612 int sock = -1; 4613 char strport[NI_MAXSERV]; 4614 4615 if (port == PORT_STREAMLOCAL) { 4616 struct sockaddr_un *sunaddr; 4617 struct addrinfo *ai; 4618 4619 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4620 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4621 return -1; 4622 } 4623 4624 /* 4625 * Fake up a struct addrinfo for AF_UNIX connections. 4626 * channel_connect_ctx_free() must check ai_family 4627 * and use free() not freeaddirinfo() for AF_UNIX. 4628 */ 4629 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4630 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4631 ai->ai_addr = (struct sockaddr *)(ai + 1); 4632 ai->ai_addrlen = sizeof(*sunaddr); 4633 ai->ai_family = AF_UNIX; 4634 ai->ai_socktype = socktype; 4635 ai->ai_protocol = PF_UNSPEC; 4636 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4637 sunaddr->sun_family = AF_UNIX; 4638 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4639 cctx->aitop = ai; 4640 } else { 4641 memset(&hints, 0, sizeof(hints)); 4642 hints.ai_family = ssh->chanctxt->IPv4or6; 4643 hints.ai_socktype = socktype; 4644 snprintf(strport, sizeof strport, "%d", port); 4645 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4646 != 0) { 4647 if (errmsg != NULL) 4648 *errmsg = ssh_gai_strerror(gaierr); 4649 if (reason != NULL) 4650 *reason = SSH2_OPEN_CONNECT_FAILED; 4651 error("connect_to %.100s: unknown host (%s)", name, 4652 ssh_gai_strerror(gaierr)); 4653 return -1; 4654 } 4655 } 4656 4657 cctx->host = xstrdup(name); 4658 cctx->port = port; 4659 cctx->ai = cctx->aitop; 4660 4661 if ((sock = connect_next(cctx)) == -1) { 4662 error("connect to %.100s port %d failed: %s", 4663 name, port, strerror(errno)); 4664 return -1; 4665 } 4666 4667 return sock; 4668 } 4669 4670 /* Return CONNECTING channel to remote host:port or local socket path */ 4671 static Channel * 4672 connect_to(struct ssh *ssh, const char *host, int port, 4673 char *ctype, char *rname) 4674 { 4675 struct channel_connect cctx; 4676 Channel *c; 4677 int sock; 4678 4679 memset(&cctx, 0, sizeof(cctx)); 4680 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4681 &cctx, NULL, NULL); 4682 if (sock == -1) { 4683 channel_connect_ctx_free(&cctx); 4684 return NULL; 4685 } 4686 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4687 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4688 c->host_port = port; 4689 c->path = xstrdup(host); 4690 c->connect_ctx = cctx; 4691 4692 return c; 4693 } 4694 4695 /* 4696 * returns either the newly connected channel or the downstream channel 4697 * that needs to deal with this connection. 4698 */ 4699 Channel * 4700 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4701 u_short listen_port, char *ctype, char *rname) 4702 { 4703 struct ssh_channels *sc = ssh->chanctxt; 4704 struct permission_set *pset = &sc->local_perms; 4705 u_int i; 4706 struct permission *perm; 4707 4708 for (i = 0; i < pset->num_permitted_user; i++) { 4709 perm = &pset->permitted_user[i]; 4710 if (open_listen_match_tcpip(perm, 4711 listen_host, listen_port, 1)) { 4712 if (perm->downstream) 4713 return perm->downstream; 4714 if (perm->port_to_connect == 0) 4715 return rdynamic_connect_prepare(ssh, 4716 ctype, rname); 4717 return connect_to(ssh, 4718 perm->host_to_connect, perm->port_to_connect, 4719 ctype, rname); 4720 } 4721 } 4722 error("WARNING: Server requests forwarding for unknown listen_port %d", 4723 listen_port); 4724 return NULL; 4725 } 4726 4727 Channel * 4728 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4729 char *ctype, char *rname) 4730 { 4731 struct ssh_channels *sc = ssh->chanctxt; 4732 struct permission_set *pset = &sc->local_perms; 4733 u_int i; 4734 struct permission *perm; 4735 4736 for (i = 0; i < pset->num_permitted_user; i++) { 4737 perm = &pset->permitted_user[i]; 4738 if (open_listen_match_streamlocal(perm, path)) { 4739 return connect_to(ssh, 4740 perm->host_to_connect, perm->port_to_connect, 4741 ctype, rname); 4742 } 4743 } 4744 error("WARNING: Server requests forwarding for unknown path %.100s", 4745 path); 4746 return NULL; 4747 } 4748 4749 /* Check if connecting to that port is permitted and connect. */ 4750 Channel * 4751 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4752 char *ctype, char *rname, int *reason, const char **errmsg) 4753 { 4754 struct ssh_channels *sc = ssh->chanctxt; 4755 struct permission_set *pset = &sc->local_perms; 4756 struct channel_connect cctx; 4757 Channel *c; 4758 u_int i, permit, permit_adm = 1; 4759 int sock; 4760 struct permission *perm; 4761 4762 permit = pset->all_permitted; 4763 if (!permit) { 4764 for (i = 0; i < pset->num_permitted_user; i++) { 4765 perm = &pset->permitted_user[i]; 4766 if (open_match(perm, host, port)) { 4767 permit = 1; 4768 break; 4769 } 4770 } 4771 } 4772 4773 if (pset->num_permitted_admin > 0) { 4774 permit_adm = 0; 4775 for (i = 0; i < pset->num_permitted_admin; i++) { 4776 perm = &pset->permitted_admin[i]; 4777 if (open_match(perm, host, port)) { 4778 permit_adm = 1; 4779 break; 4780 } 4781 } 4782 } 4783 4784 if (!permit || !permit_adm) { 4785 logit("Received request from %.100s port %d to connect to " 4786 "host %.100s port %d, but the request was denied.", 4787 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4788 if (reason != NULL) 4789 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4790 return NULL; 4791 } 4792 4793 memset(&cctx, 0, sizeof(cctx)); 4794 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4795 &cctx, reason, errmsg); 4796 if (sock == -1) { 4797 channel_connect_ctx_free(&cctx); 4798 return NULL; 4799 } 4800 4801 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4802 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4803 c->host_port = port; 4804 c->path = xstrdup(host); 4805 c->connect_ctx = cctx; 4806 4807 return c; 4808 } 4809 4810 /* Check if connecting to that path is permitted and connect. */ 4811 Channel * 4812 channel_connect_to_path(struct ssh *ssh, const char *path, 4813 char *ctype, char *rname) 4814 { 4815 struct ssh_channels *sc = ssh->chanctxt; 4816 struct permission_set *pset = &sc->local_perms; 4817 u_int i, permit, permit_adm = 1; 4818 struct permission *perm; 4819 4820 permit = pset->all_permitted; 4821 if (!permit) { 4822 for (i = 0; i < pset->num_permitted_user; i++) { 4823 perm = &pset->permitted_user[i]; 4824 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4825 permit = 1; 4826 break; 4827 } 4828 } 4829 } 4830 4831 if (pset->num_permitted_admin > 0) { 4832 permit_adm = 0; 4833 for (i = 0; i < pset->num_permitted_admin; i++) { 4834 perm = &pset->permitted_admin[i]; 4835 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4836 permit_adm = 1; 4837 break; 4838 } 4839 } 4840 } 4841 4842 if (!permit || !permit_adm) { 4843 logit("Received request to connect to path %.100s, " 4844 "but the request was denied.", path); 4845 return NULL; 4846 } 4847 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4848 } 4849 4850 void 4851 channel_send_window_changes(struct ssh *ssh) 4852 { 4853 struct ssh_channels *sc = ssh->chanctxt; 4854 struct winsize ws; 4855 int r; 4856 u_int i; 4857 4858 for (i = 0; i < sc->channels_alloc; i++) { 4859 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4860 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4861 continue; 4862 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4863 continue; 4864 channel_request_start(ssh, i, "window-change", 0); 4865 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4866 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4867 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4868 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4869 (r = sshpkt_send(ssh)) != 0) 4870 fatal_fr(r, "channel %u; send window-change", i); 4871 } 4872 } 4873 4874 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4875 static Channel * 4876 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4877 { 4878 Channel *c; 4879 int r; 4880 4881 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4882 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4883 c->host_port = 0; 4884 c->path = NULL; 4885 4886 /* 4887 * We need to open the channel before we have a FD, 4888 * so that we can get SOCKS header from peer. 4889 */ 4890 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4891 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4892 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4893 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4894 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4895 fatal_fr(r, "channel %i; confirm", c->self); 4896 return c; 4897 } 4898 4899 /* Return CONNECTING socket to remote host:port or local socket path */ 4900 static int 4901 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4902 { 4903 struct ssh_channels *sc = ssh->chanctxt; 4904 struct permission_set *pset = &sc->local_perms; 4905 struct permission *perm; 4906 struct channel_connect cctx; 4907 u_int i, permit_adm = 1; 4908 int sock; 4909 4910 if (pset->num_permitted_admin > 0) { 4911 permit_adm = 0; 4912 for (i = 0; i < pset->num_permitted_admin; i++) { 4913 perm = &pset->permitted_admin[i]; 4914 if (open_match(perm, c->path, c->host_port)) { 4915 permit_adm = 1; 4916 break; 4917 } 4918 } 4919 } 4920 if (!permit_adm) { 4921 debug_f("requested forward not permitted"); 4922 return -1; 4923 } 4924 4925 memset(&cctx, 0, sizeof(cctx)); 4926 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4927 NULL, &cctx, NULL, NULL); 4928 if (sock == -1) 4929 channel_connect_ctx_free(&cctx); 4930 else { 4931 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4932 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4933 c->connect_ctx = cctx; 4934 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4935 } 4936 return sock; 4937 } 4938 4939 /* -- X11 forwarding */ 4940 4941 /* 4942 * Creates an internet domain socket for listening for X11 connections. 4943 * Returns 0 and a suitable display number for the DISPLAY variable 4944 * stored in display_numberp , or -1 if an error occurs. 4945 */ 4946 int 4947 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4948 int x11_use_localhost, int single_connection, 4949 u_int *display_numberp, int **chanids) 4950 { 4951 Channel *nc = NULL; 4952 int display_number, sock; 4953 u_short port; 4954 struct addrinfo hints, *ai, *aitop; 4955 char strport[NI_MAXSERV]; 4956 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4957 4958 if (chanids == NULL) 4959 return -1; 4960 4961 for (display_number = x11_display_offset; 4962 display_number < MAX_DISPLAYS; 4963 display_number++) { 4964 port = 6000 + display_number; 4965 memset(&hints, 0, sizeof(hints)); 4966 hints.ai_family = ssh->chanctxt->IPv4or6; 4967 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4968 hints.ai_socktype = SOCK_STREAM; 4969 snprintf(strport, sizeof strport, "%d", port); 4970 if ((gaierr = getaddrinfo(NULL, strport, 4971 &hints, &aitop)) != 0) { 4972 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4973 return -1; 4974 } 4975 for (ai = aitop; ai; ai = ai->ai_next) { 4976 if (ai->ai_family != AF_INET && 4977 ai->ai_family != AF_INET6) 4978 continue; 4979 sock = socket(ai->ai_family, ai->ai_socktype, 4980 ai->ai_protocol); 4981 if (sock == -1) { 4982 error("socket: %.100s", strerror(errno)); 4983 freeaddrinfo(aitop); 4984 return -1; 4985 } 4986 set_reuseaddr(sock); 4987 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4988 debug2_f("bind port %d: %.100s", port, 4989 strerror(errno)); 4990 close(sock); 4991 for (n = 0; n < num_socks; n++) 4992 close(socks[n]); 4993 num_socks = 0; 4994 break; 4995 } 4996 socks[num_socks++] = sock; 4997 if (num_socks == NUM_SOCKS) 4998 break; 4999 } 5000 freeaddrinfo(aitop); 5001 if (num_socks > 0) 5002 break; 5003 } 5004 if (display_number >= MAX_DISPLAYS) { 5005 error("Failed to allocate internet-domain X11 display socket."); 5006 return -1; 5007 } 5008 /* Start listening for connections on the socket. */ 5009 for (n = 0; n < num_socks; n++) { 5010 sock = socks[n]; 5011 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5012 error("listen: %.100s", strerror(errno)); 5013 close(sock); 5014 return -1; 5015 } 5016 } 5017 5018 /* Allocate a channel for each socket. */ 5019 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5020 for (n = 0; n < num_socks; n++) { 5021 sock = socks[n]; 5022 nc = channel_new(ssh, "x11-listener", 5023 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5024 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5025 0, "X11 inet listener", 1); 5026 nc->single_connection = single_connection; 5027 (*chanids)[n] = nc->self; 5028 } 5029 (*chanids)[n] = -1; 5030 5031 /* Return the display number for the DISPLAY environment variable. */ 5032 *display_numberp = display_number; 5033 return 0; 5034 } 5035 5036 static int 5037 connect_local_xsocket(u_int dnr) 5038 { 5039 int sock; 5040 struct sockaddr_un addr; 5041 5042 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5043 if (sock == -1) 5044 error("socket: %.100s", strerror(errno)); 5045 memset(&addr, 0, sizeof(addr)); 5046 addr.sun_family = AF_UNIX; 5047 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 5048 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5049 return sock; 5050 close(sock); 5051 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5052 return -1; 5053 } 5054 5055 int 5056 x11_connect_display(struct ssh *ssh) 5057 { 5058 u_int display_number; 5059 const char *display; 5060 char buf[1024], *cp; 5061 struct addrinfo hints, *ai, *aitop; 5062 char strport[NI_MAXSERV]; 5063 int gaierr, sock = 0; 5064 5065 /* Try to open a socket for the local X server. */ 5066 display = getenv("DISPLAY"); 5067 if (!display) { 5068 error("DISPLAY not set."); 5069 return -1; 5070 } 5071 /* 5072 * Now we decode the value of the DISPLAY variable and make a 5073 * connection to the real X server. 5074 */ 5075 5076 /* 5077 * Check if it is a unix domain socket. Unix domain displays are in 5078 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5079 */ 5080 if (strncmp(display, "unix:", 5) == 0 || 5081 display[0] == ':') { 5082 /* Connect to the unix domain socket. */ 5083 if (sscanf(strrchr(display, ':') + 1, "%u", 5084 &display_number) != 1) { 5085 error("Could not parse display number from DISPLAY: " 5086 "%.100s", display); 5087 return -1; 5088 } 5089 /* Create a socket. */ 5090 sock = connect_local_xsocket(display_number); 5091 if (sock < 0) 5092 return -1; 5093 5094 /* OK, we now have a connection to the display. */ 5095 return sock; 5096 } 5097 /* 5098 * Connect to an inet socket. The DISPLAY value is supposedly 5099 * hostname:d[.s], where hostname may also be numeric IP address. 5100 */ 5101 strlcpy(buf, display, sizeof(buf)); 5102 cp = strchr(buf, ':'); 5103 if (!cp) { 5104 error("Could not find ':' in DISPLAY: %.100s", display); 5105 return -1; 5106 } 5107 *cp = 0; 5108 /* 5109 * buf now contains the host name. But first we parse the 5110 * display number. 5111 */ 5112 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5113 error("Could not parse display number from DISPLAY: %.100s", 5114 display); 5115 return -1; 5116 } 5117 5118 /* Look up the host address */ 5119 memset(&hints, 0, sizeof(hints)); 5120 hints.ai_family = ssh->chanctxt->IPv4or6; 5121 hints.ai_socktype = SOCK_STREAM; 5122 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5123 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5124 error("%.100s: unknown host. (%s)", buf, 5125 ssh_gai_strerror(gaierr)); 5126 return -1; 5127 } 5128 for (ai = aitop; ai; ai = ai->ai_next) { 5129 /* Create a socket. */ 5130 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5131 if (sock == -1) { 5132 debug2("socket: %.100s", strerror(errno)); 5133 continue; 5134 } 5135 /* Connect it to the display. */ 5136 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5137 debug2("connect %.100s port %u: %.100s", buf, 5138 6000 + display_number, strerror(errno)); 5139 close(sock); 5140 continue; 5141 } 5142 /* Success */ 5143 break; 5144 } 5145 freeaddrinfo(aitop); 5146 if (!ai) { 5147 error("connect %.100s port %u: %.100s", buf, 5148 6000 + display_number, strerror(errno)); 5149 return -1; 5150 } 5151 set_nodelay(sock); 5152 return sock; 5153 } 5154 5155 /* 5156 * Requests forwarding of X11 connections, generates fake authentication 5157 * data, and enables authentication spoofing. 5158 * This should be called in the client only. 5159 */ 5160 void 5161 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5162 const char *disp, const char *proto, const char *data, int want_reply) 5163 { 5164 struct ssh_channels *sc = ssh->chanctxt; 5165 u_int data_len = (u_int) strlen(data) / 2; 5166 u_int i, value; 5167 const char *cp; 5168 char *new_data; 5169 int r, screen_number; 5170 5171 if (sc->x11_saved_display == NULL) 5172 sc->x11_saved_display = xstrdup(disp); 5173 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5174 error("x11_request_forwarding_with_spoofing: different " 5175 "$DISPLAY already forwarded"); 5176 return; 5177 } 5178 5179 cp = strchr(disp, ':'); 5180 if (cp) 5181 cp = strchr(cp, '.'); 5182 if (cp) 5183 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5184 else 5185 screen_number = 0; 5186 5187 if (sc->x11_saved_proto == NULL) { 5188 /* Save protocol name. */ 5189 sc->x11_saved_proto = xstrdup(proto); 5190 5191 /* Extract real authentication data. */ 5192 sc->x11_saved_data = xmalloc(data_len); 5193 for (i = 0; i < data_len; i++) { 5194 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5195 fatal("x11_request_forwarding: bad " 5196 "authentication data: %.100s", data); 5197 } 5198 sc->x11_saved_data[i] = value; 5199 } 5200 sc->x11_saved_data_len = data_len; 5201 5202 /* Generate fake data of the same length. */ 5203 sc->x11_fake_data = xmalloc(data_len); 5204 arc4random_buf(sc->x11_fake_data, data_len); 5205 sc->x11_fake_data_len = data_len; 5206 } 5207 5208 /* Convert the fake data into hex. */ 5209 new_data = tohex(sc->x11_fake_data, data_len); 5210 5211 /* Send the request packet. */ 5212 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5213 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5214 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5215 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5216 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5217 (r = sshpkt_send(ssh)) != 0 || 5218 (r = ssh_packet_write_wait(ssh)) != 0) 5219 fatal_fr(r, "send x11-req"); 5220 free(new_data); 5221 } 5222