1 /* $NetBSD: channels.c,v 1.40 2023/08/07 00:44:25 rin Exp $ */ 2 /* $OpenBSD: channels.c,v 1.430 2023/03/10 03:01:51 dtucker Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * This file contains functions for generic socket connection forwarding. 8 * There is also code for initiating connection forwarding for X11 connections, 9 * arbitrary tcp/ip connections, and the authentication agent connection. 10 * 11 * As far as I am concerned, the code I have written for this software 12 * can be used freely for any purpose. Any derived versions of this 13 * software must be clearly marked as such, and if the derived work is 14 * incompatible with the protocol description in the RFC file, it must be 15 * called by a name other than "ssh" or "Secure Shell". 16 * 17 * SSH2 support added by Markus Friedl. 18 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 19 * Copyright (c) 1999 Dug Song. All rights reserved. 20 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 32 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 34 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 41 */ 42 43 #include "includes.h" 44 __RCSID("$NetBSD: channels.c,v 1.40 2023/08/07 00:44:25 rin Exp $"); 45 #include <sys/param.h> 46 #include <sys/types.h> 47 #include <sys/stat.h> 48 #include <sys/ioctl.h> 49 #include <sys/un.h> 50 #include <sys/socket.h> 51 #include <sys/time.h> 52 #include <sys/queue.h> 53 54 #include <netinet/in.h> 55 #include <arpa/inet.h> 56 57 #include <errno.h> 58 #include <fcntl.h> 59 #include <limits.h> 60 #include <netdb.h> 61 #include <poll.h> 62 #include <stdarg.h> 63 #include <stdint.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <termios.h> 68 #include <unistd.h> 69 70 #include "xmalloc.h" 71 #include "ssh.h" 72 #include "ssh2.h" 73 #include "ssherr.h" 74 #include "sshbuf.h" 75 #include "packet.h" 76 #include "log.h" 77 #include "misc.h" 78 #include "channels.h" 79 #include "compat.h" 80 #include "canohost.h" 81 #include "sshkey.h" 82 #include "authfd.h" 83 #include "pathnames.h" 84 #include "match.h" 85 86 87 static int hpn_disabled = 0; 88 static int hpn_buffer_size = 2 * 1024 * 1024; 89 90 /* XXX remove once we're satisfied there's no lurking bugs */ 91 /* #define DEBUG_CHANNEL_POLL 1 */ 92 93 /* -- agent forwarding */ 94 #define NUM_SOCKS 10 95 96 /* -- tcp forwarding */ 97 /* special-case port number meaning allow any port */ 98 #define FWD_PERMIT_ANY_PORT 0 99 100 /* special-case wildcard meaning allow any host */ 101 #define FWD_PERMIT_ANY_HOST "*" 102 103 /* -- X11 forwarding */ 104 /* Maximum number of fake X11 displays to try. */ 105 #define MAX_DISPLAYS 1000 106 107 /* Per-channel callback for pre/post IO actions */ 108 typedef void chan_fn(struct ssh *, Channel *c); 109 110 /* 111 * Data structure for storing which hosts are permitted for forward requests. 112 * The local sides of any remote forwards are stored in this array to prevent 113 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 114 * network (which might be behind a firewall). 115 */ 116 /* XXX: streamlocal wants a path instead of host:port */ 117 /* Overload host_to_connect; we could just make this match Forward */ 118 /* XXX - can we use listen_host instead of listen_path? */ 119 struct permission { 120 char *host_to_connect; /* Connect to 'host'. */ 121 int port_to_connect; /* Connect to 'port'. */ 122 char *listen_host; /* Remote side should listen address. */ 123 char *listen_path; /* Remote side should listen path. */ 124 int listen_port; /* Remote side should listen port. */ 125 Channel *downstream; /* Downstream mux*/ 126 }; 127 128 /* 129 * Stores the forwarding permission state for a single direction (local or 130 * remote). 131 */ 132 struct permission_set { 133 /* 134 * List of all local permitted host/port pairs to allow for the 135 * user. 136 */ 137 u_int num_permitted_user; 138 struct permission *permitted_user; 139 140 /* 141 * List of all permitted host/port pairs to allow for the admin. 142 */ 143 u_int num_permitted_admin; 144 struct permission *permitted_admin; 145 146 /* 147 * If this is true, all opens/listens are permitted. This is the 148 * case on the server on which we have to trust the client anyway, 149 * and the user could do anything after logging in. 150 */ 151 int all_permitted; 152 }; 153 154 /* Used to record timeouts per channel type */ 155 struct ssh_channel_timeout { 156 char *type_pattern; 157 u_int timeout_secs; 158 }; 159 160 /* Master structure for channels state */ 161 struct ssh_channels { 162 /* 163 * Pointer to an array containing all allocated channels. The array 164 * is dynamically extended as needed. 165 */ 166 Channel **channels; 167 168 /* 169 * Size of the channel array. All slots of the array must always be 170 * initialized (at least the type field); unused slots set to NULL 171 */ 172 u_int channels_alloc; 173 174 /* 175 * 'channel_pre*' are called just before IO to add any bits 176 * relevant to channels in the c->io_want bitmasks. 177 * 178 * 'channel_post*': perform any appropriate operations for 179 * channels which have c->io_ready events pending. 180 */ 181 chan_fn **channel_pre; 182 chan_fn **channel_post; 183 184 /* -- tcp forwarding */ 185 struct permission_set local_perms; 186 struct permission_set remote_perms; 187 188 /* -- X11 forwarding */ 189 190 /* Saved X11 local (client) display. */ 191 char *x11_saved_display; 192 193 /* Saved X11 authentication protocol name. */ 194 char *x11_saved_proto; 195 196 /* Saved X11 authentication data. This is the real data. */ 197 char *x11_saved_data; 198 u_int x11_saved_data_len; 199 200 /* Deadline after which all X11 connections are refused */ 201 time_t x11_refuse_time; 202 203 /* 204 * Fake X11 authentication data. This is what the server will be 205 * sending us; we should replace any occurrences of this by the 206 * real data. 207 */ 208 u_char *x11_fake_data; 209 u_int x11_fake_data_len; 210 211 /* AF_UNSPEC or AF_INET or AF_INET6 */ 212 int IPv4or6; 213 214 /* Channel timeouts by type */ 215 struct ssh_channel_timeout *timeouts; 216 size_t ntimeouts; 217 }; 218 219 /* helper */ 220 static void port_open_helper(struct ssh *ssh, Channel *c, const char *rtype); 221 static const char *channel_rfwd_bind_host(const char *listen_host); 222 223 /* non-blocking connect helpers */ 224 static int connect_next(struct channel_connect *); 225 static void channel_connect_ctx_free(struct channel_connect *); 226 static Channel *rdynamic_connect_prepare(struct ssh *, const char *, 227 const char *); 228 static int rdynamic_connect_finish(struct ssh *, Channel *); 229 230 /* Setup helper */ 231 static void channel_handler_init(struct ssh_channels *sc); 232 233 /* -- channel core */ 234 235 void 236 channel_init_channels(struct ssh *ssh) 237 { 238 struct ssh_channels *sc; 239 240 if ((sc = calloc(1, sizeof(*sc))) == NULL) 241 fatal_f("allocation failed"); 242 sc->channels_alloc = 10; 243 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 244 sc->IPv4or6 = AF_UNSPEC; 245 channel_handler_init(sc); 246 247 ssh->chanctxt = sc; 248 } 249 250 Channel * 251 channel_by_id(struct ssh *ssh, int id) 252 { 253 Channel *c; 254 255 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 256 logit_f("%d: bad id", id); 257 return NULL; 258 } 259 c = ssh->chanctxt->channels[id]; 260 if (c == NULL) { 261 logit_f("%d: bad id: channel free", id); 262 return NULL; 263 } 264 return c; 265 } 266 267 Channel * 268 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 269 { 270 Channel *c; 271 u_int i; 272 273 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 274 c = ssh->chanctxt->channels[i]; 275 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 276 return c; 277 } 278 return NULL; 279 } 280 281 /* 282 * Returns the channel if it is allowed to receive protocol messages. 283 * Private channels, like listening sockets, may not receive messages. 284 */ 285 Channel * 286 channel_lookup(struct ssh *ssh, int id) 287 { 288 Channel *c; 289 290 if ((c = channel_by_id(ssh, id)) == NULL) 291 return NULL; 292 293 switch (c->type) { 294 case SSH_CHANNEL_X11_OPEN: 295 case SSH_CHANNEL_LARVAL: 296 case SSH_CHANNEL_CONNECTING: 297 case SSH_CHANNEL_DYNAMIC: 298 case SSH_CHANNEL_RDYNAMIC_OPEN: 299 case SSH_CHANNEL_RDYNAMIC_FINISH: 300 case SSH_CHANNEL_OPENING: 301 case SSH_CHANNEL_OPEN: 302 case SSH_CHANNEL_ABANDONED: 303 case SSH_CHANNEL_MUX_PROXY: 304 return c; 305 } 306 logit("Non-public channel %d, type %d.", id, c->type); 307 return NULL; 308 } 309 310 /* 311 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 312 * match type_pattern. 313 */ 314 void 315 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 316 u_int timeout_secs) 317 { 318 struct ssh_channels *sc = ssh->chanctxt; 319 320 debug2_f("channel type \"%s\" timeout %u seconds", 321 type_pattern, timeout_secs); 322 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 323 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 324 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 325 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 326 sc->ntimeouts++; 327 } 328 329 /* Clears all previously-added channel timeouts */ 330 void 331 channel_clear_timeouts(struct ssh *ssh) 332 { 333 struct ssh_channels *sc = ssh->chanctxt; 334 size_t i; 335 336 debug3_f("clearing"); 337 for (i = 0; i < sc->ntimeouts; i++) 338 free(sc->timeouts[i].type_pattern); 339 free(sc->timeouts); 340 sc->timeouts = NULL; 341 sc->ntimeouts = 0; 342 } 343 344 static u_int 345 lookup_timeout(struct ssh *ssh, const char *type) 346 { 347 struct ssh_channels *sc = ssh->chanctxt; 348 size_t i; 349 350 for (i = 0; i < sc->ntimeouts; i++) { 351 if (match_pattern(type, sc->timeouts[i].type_pattern)) 352 return sc->timeouts[i].timeout_secs; 353 } 354 355 return 0; 356 } 357 358 /* 359 * Sets "extended type" of a channel; used by session layer to add additional 360 * information about channel types (e.g. shell, login, subsystem) that can then 361 * be used to select timeouts. 362 * Will reset c->inactive_deadline as a side-effect. 363 */ 364 void 365 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 366 { 367 Channel *c; 368 369 if ((c = channel_by_id(ssh, id)) == NULL) 370 fatal_f("missing channel %d", id); 371 if (c->xctype != NULL) 372 free(c->xctype); 373 c->xctype = xstrdup(xctype); 374 /* Type has changed, so look up inactivity deadline again */ 375 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 376 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 377 c->inactive_deadline); 378 } 379 380 /* 381 * Register filedescriptors for a channel, used when allocating a channel or 382 * when the channel consumer/producer is ready, e.g. shell exec'd 383 */ 384 static void 385 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 386 int extusage, int nonblock, int is_tty) 387 { 388 int val; 389 390 if (rfd != -1) 391 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 392 if (wfd != -1 && wfd != rfd) 393 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 394 if (efd != -1 && efd != rfd && efd != wfd) 395 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 396 397 c->rfd = rfd; 398 c->wfd = wfd; 399 c->sock = (rfd == wfd) ? rfd : -1; 400 c->efd = efd; 401 c->extended_usage = extusage; 402 403 if ((c->isatty = is_tty) != 0) 404 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 405 406 /* enable nonblocking mode */ 407 c->restore_block = 0; 408 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 409 /* 410 * Special handling for stdio file descriptors: do not set 411 * non-blocking mode if they are TTYs. Otherwise prepare to 412 * restore their blocking state on exit to avoid interfering 413 * with other programs that follow. 414 */ 415 if (rfd != -1 && !isatty(rfd) && 416 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 417 c->restore_flags[0] = val; 418 c->restore_block |= CHANNEL_RESTORE_RFD; 419 set_nonblock(rfd); 420 } 421 if (wfd != -1 && !isatty(wfd) && 422 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 423 c->restore_flags[1] = val; 424 c->restore_block |= CHANNEL_RESTORE_WFD; 425 set_nonblock(wfd); 426 } 427 if (efd != -1 && !isatty(efd) && 428 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 429 c->restore_flags[2] = val; 430 c->restore_block |= CHANNEL_RESTORE_EFD; 431 set_nonblock(efd); 432 } 433 } else if (nonblock) { 434 if (rfd != -1) 435 set_nonblock(rfd); 436 if (wfd != -1) 437 set_nonblock(wfd); 438 if (efd != -1) 439 set_nonblock(efd); 440 } 441 } 442 443 /* 444 * Allocate a new channel object and set its type and socket. 445 */ 446 Channel * 447 channel_new(struct ssh *ssh, const char *ctype, int type, int rfd, int wfd, 448 int efd, u_int window, u_int maxpack, int extusage, const char *remote_name, 449 int nonblock) 450 { 451 struct ssh_channels *sc = ssh->chanctxt; 452 u_int i, found = 0 /* XXXGCC12 */; 453 Channel *c; 454 int r; 455 456 /* Try to find a free slot where to put the new channel. */ 457 for (i = 0; i < sc->channels_alloc; i++) { 458 if (sc->channels[i] == NULL) { 459 /* Found a free slot. */ 460 found = i; 461 break; 462 } 463 } 464 if (i >= sc->channels_alloc) { 465 /* 466 * There are no free slots. Take last+1 slot and expand 467 * the array. 468 */ 469 found = sc->channels_alloc; 470 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 471 fatal_f("internal error: channels_alloc %d too big", 472 sc->channels_alloc); 473 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 474 sc->channels_alloc + 10, sizeof(*sc->channels)); 475 sc->channels_alloc += 10; 476 debug2("channel: expanding %d", sc->channels_alloc); 477 } 478 /* Initialize and return new channel. */ 479 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 480 if ((c->input = sshbuf_new()) == NULL || 481 (c->output = sshbuf_new()) == NULL || 482 (c->extended = sshbuf_new()) == NULL) 483 fatal_f("sshbuf_new failed"); 484 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 485 fatal_fr(r, "sshbuf_set_max_size"); 486 c->ostate = CHAN_OUTPUT_OPEN; 487 c->istate = CHAN_INPUT_OPEN; 488 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 489 c->self = found; 490 c->type = type; 491 c->ctype = __UNCONST(ctype); 492 c->local_window = window; 493 c->local_window_max = window; 494 c->local_maxpacket = maxpack; 495 c->dynamic_window = 0; 496 c->remote_id = -1; 497 c->remote_name = xstrdup(remote_name); 498 c->ctl_chan = -1; 499 c->delayed = 1; /* prevent call to channel_post handler */ 500 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 501 TAILQ_INIT(&c->status_confirms); 502 debug("channel %d: new %s [%s] (inactive timeout: %u)", 503 found, c->ctype, remote_name, c->inactive_deadline); 504 return c; 505 } 506 507 int 508 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 509 { 510 int ret, fd = *fdp; 511 512 if (fd == -1) 513 return 0; 514 515 /* restore blocking */ 516 if (*fdp == c->rfd && 517 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 518 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 519 else if (*fdp == c->wfd && 520 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 521 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 522 else if (*fdp == c->efd && 523 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 524 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 525 526 if (*fdp == c->rfd) { 527 c->io_want &= ~SSH_CHAN_IO_RFD; 528 c->io_ready &= ~SSH_CHAN_IO_RFD; 529 c->rfd = -1; 530 c->pfds[0] = -1; 531 } 532 if (*fdp == c->wfd) { 533 c->io_want &= ~SSH_CHAN_IO_WFD; 534 c->io_ready &= ~SSH_CHAN_IO_WFD; 535 c->wfd = -1; 536 c->pfds[1] = -1; 537 } 538 if (*fdp == c->efd) { 539 c->io_want &= ~SSH_CHAN_IO_EFD; 540 c->io_ready &= ~SSH_CHAN_IO_EFD; 541 c->efd = -1; 542 c->pfds[2] = -1; 543 } 544 if (*fdp == c->sock) { 545 c->io_want &= ~SSH_CHAN_IO_SOCK; 546 c->io_ready &= ~SSH_CHAN_IO_SOCK; 547 c->sock = -1; 548 c->pfds[3] = -1; 549 } 550 551 ret = close(fd); 552 *fdp = -1; /* probably redundant */ 553 return ret; 554 } 555 556 /* Close all channel fd/socket. */ 557 static void 558 channel_close_fds(struct ssh *ssh, Channel *c) 559 { 560 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 561 562 channel_close_fd(ssh, c, &c->sock); 563 if (rfd != sock) 564 channel_close_fd(ssh, c, &c->rfd); 565 if (wfd != sock && wfd != rfd) 566 channel_close_fd(ssh, c, &c->wfd); 567 if (efd != sock && efd != rfd && efd != wfd) 568 channel_close_fd(ssh, c, &c->efd); 569 } 570 571 static void 572 fwd_perm_clear(struct permission *perm) 573 { 574 free(perm->host_to_connect); 575 free(perm->listen_host); 576 free(perm->listen_path); 577 memset(perm, 0, sizeof(*perm)); 578 } 579 580 /* Returns an printable name for the specified forwarding permission list */ 581 static const char * 582 fwd_ident(int who, int where) 583 { 584 if (who == FORWARD_ADM) { 585 if (where == FORWARD_LOCAL) 586 return "admin local"; 587 else if (where == FORWARD_REMOTE) 588 return "admin remote"; 589 } else if (who == FORWARD_USER) { 590 if (where == FORWARD_LOCAL) 591 return "user local"; 592 else if (where == FORWARD_REMOTE) 593 return "user remote"; 594 } 595 fatal("Unknown forward permission list %d/%d", who, where); 596 } 597 598 /* Returns the forwarding permission list for the specified direction */ 599 static struct permission_set * 600 permission_set_get(struct ssh *ssh, int where) 601 { 602 struct ssh_channels *sc = ssh->chanctxt; 603 604 switch (where) { 605 case FORWARD_LOCAL: 606 return &sc->local_perms; 607 break; 608 case FORWARD_REMOTE: 609 return &sc->remote_perms; 610 break; 611 default: 612 fatal_f("invalid forwarding direction %d", where); 613 } 614 } 615 616 /* Returns pointers to the specified forwarding list and its element count */ 617 static void 618 permission_set_get_array(struct ssh *ssh, int who, int where, 619 struct permission ***permpp, u_int **npermpp) 620 { 621 struct permission_set *pset = permission_set_get(ssh, where); 622 623 switch (who) { 624 case FORWARD_USER: 625 *permpp = &pset->permitted_user; 626 *npermpp = &pset->num_permitted_user; 627 break; 628 case FORWARD_ADM: 629 *permpp = &pset->permitted_admin; 630 *npermpp = &pset->num_permitted_admin; 631 break; 632 default: 633 fatal_f("invalid forwarding client %d", who); 634 } 635 } 636 637 /* Adds an entry to the specified forwarding list */ 638 static int 639 permission_set_add(struct ssh *ssh, int who, int where, 640 const char *host_to_connect, int port_to_connect, 641 const char *listen_host, const char *listen_path, int listen_port, 642 Channel *downstream) 643 { 644 struct permission **permp; 645 u_int n, *npermp; 646 647 permission_set_get_array(ssh, who, where, &permp, &npermp); 648 649 if (*npermp >= INT_MAX) 650 fatal_f("%s overflow", fwd_ident(who, where)); 651 652 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 653 n = (*npermp)++; 654 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 655 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 656 (*permp)[n].port_to_connect = port_to_connect; 657 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 658 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 659 (*permp)[n].listen_port = listen_port; 660 (*permp)[n].downstream = downstream; 661 #undef MAYBE_DUP 662 return (int)n; 663 } 664 665 static void 666 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 667 { 668 struct ssh_channels *sc = ssh->chanctxt; 669 struct permission_set *pset = &sc->local_perms; 670 struct permission *perm; 671 int r; 672 u_int i; 673 674 for (i = 0; i < pset->num_permitted_user; i++) { 675 perm = &pset->permitted_user[i]; 676 if (perm->downstream != c) 677 continue; 678 679 /* cancel on the server, since mux client is gone */ 680 debug("channel %d: cleanup remote forward for %s:%u", 681 c->self, perm->listen_host, perm->listen_port); 682 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 683 (r = sshpkt_put_cstring(ssh, 684 "cancel-tcpip-forward")) != 0 || 685 (r = sshpkt_put_u8(ssh, 0)) != 0 || 686 (r = sshpkt_put_cstring(ssh, 687 channel_rfwd_bind_host(perm->listen_host))) != 0 || 688 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 689 (r = sshpkt_send(ssh)) != 0) { 690 fatal_fr(r, "channel %i", c->self); 691 } 692 fwd_perm_clear(perm); /* unregister */ 693 } 694 } 695 696 /* Free the channel and close its fd/socket. */ 697 void 698 channel_free(struct ssh *ssh, Channel *c) 699 { 700 struct ssh_channels *sc = ssh->chanctxt; 701 char *s; 702 u_int i, n; 703 Channel *other; 704 struct channel_confirm *cc; 705 706 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 707 if ((other = sc->channels[i]) == NULL) 708 continue; 709 n++; 710 /* detach from mux client and prepare for closing */ 711 if (c->type == SSH_CHANNEL_MUX_CLIENT && 712 other->type == SSH_CHANNEL_MUX_PROXY && 713 other->mux_ctx == c) { 714 other->mux_ctx = NULL; 715 other->type = SSH_CHANNEL_OPEN; 716 other->istate = CHAN_INPUT_CLOSED; 717 other->ostate = CHAN_OUTPUT_CLOSED; 718 } 719 } 720 debug("channel %d: free: %s, nchannels %u", c->self, 721 c->remote_name ? c->remote_name : "???", n); 722 723 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 724 mux_remove_remote_forwardings(ssh, c); 725 free(c->mux_ctx); 726 c->mux_ctx = NULL; 727 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 728 free(c->mux_ctx); 729 c->mux_ctx = NULL; 730 } 731 732 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 733 s = channel_open_message(ssh); 734 debug3("channel %d: status: %s", c->self, s); 735 free(s); 736 } 737 738 channel_close_fds(ssh, c); 739 sshbuf_free(c->input); 740 sshbuf_free(c->output); 741 sshbuf_free(c->extended); 742 c->input = c->output = c->extended = NULL; 743 free(c->remote_name); 744 c->remote_name = NULL; 745 free(c->path); 746 c->path = NULL; 747 free(c->listening_addr); 748 c->listening_addr = NULL; 749 free(c->xctype); 750 c->xctype = NULL; 751 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 752 if (cc->abandon_cb != NULL) 753 cc->abandon_cb(ssh, c, cc->ctx); 754 TAILQ_REMOVE(&c->status_confirms, cc, entry); 755 freezero(cc, sizeof(*cc)); 756 } 757 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 758 c->filter_cleanup(ssh, c->self, c->filter_ctx); 759 sc->channels[c->self] = NULL; 760 freezero(c, sizeof(*c)); 761 } 762 763 void 764 channel_free_all(struct ssh *ssh) 765 { 766 u_int i; 767 struct ssh_channels *sc = ssh->chanctxt; 768 769 for (i = 0; i < sc->channels_alloc; i++) 770 if (sc->channels[i] != NULL) 771 channel_free(ssh, sc->channels[i]); 772 773 free(sc->channels); 774 sc->channels = NULL; 775 sc->channels_alloc = 0; 776 777 free(sc->x11_saved_display); 778 sc->x11_saved_display = NULL; 779 780 free(sc->x11_saved_proto); 781 sc->x11_saved_proto = NULL; 782 783 free(sc->x11_saved_data); 784 sc->x11_saved_data = NULL; 785 sc->x11_saved_data_len = 0; 786 787 free(sc->x11_fake_data); 788 sc->x11_fake_data = NULL; 789 sc->x11_fake_data_len = 0; 790 } 791 792 /* 793 * Closes the sockets/fds of all channels. This is used to close extra file 794 * descriptors after a fork. 795 */ 796 void 797 channel_close_all(struct ssh *ssh) 798 { 799 u_int i; 800 801 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 802 if (ssh->chanctxt->channels[i] != NULL) 803 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 804 } 805 806 /* 807 * Stop listening to channels. 808 */ 809 void 810 channel_stop_listening(struct ssh *ssh) 811 { 812 u_int i; 813 Channel *c; 814 815 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 816 c = ssh->chanctxt->channels[i]; 817 if (c != NULL) { 818 switch (c->type) { 819 case SSH_CHANNEL_AUTH_SOCKET: 820 case SSH_CHANNEL_PORT_LISTENER: 821 case SSH_CHANNEL_RPORT_LISTENER: 822 case SSH_CHANNEL_X11_LISTENER: 823 case SSH_CHANNEL_UNIX_LISTENER: 824 case SSH_CHANNEL_RUNIX_LISTENER: 825 channel_close_fd(ssh, c, &c->sock); 826 channel_free(ssh, c); 827 break; 828 } 829 } 830 } 831 } 832 833 /* 834 * Returns true if no channel has too much buffered data, and false if one or 835 * more channel is overfull. 836 */ 837 int 838 channel_not_very_much_buffered_data(struct ssh *ssh) 839 { 840 u_int i; 841 u_int maxsize = ssh_packet_get_maxsize(ssh); 842 Channel *c; 843 844 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 845 c = ssh->chanctxt->channels[i]; 846 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 847 continue; 848 if (sshbuf_len(c->output) > maxsize) { 849 debug2("channel %d: big output buffer %zu > %u", 850 c->self, sshbuf_len(c->output), maxsize); 851 return 0; 852 } 853 } 854 return 1; 855 } 856 857 /* Returns true if any channel is still open. */ 858 int 859 channel_still_open(struct ssh *ssh) 860 { 861 u_int i; 862 Channel *c; 863 864 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 865 c = ssh->chanctxt->channels[i]; 866 if (c == NULL) 867 continue; 868 switch (c->type) { 869 case SSH_CHANNEL_X11_LISTENER: 870 case SSH_CHANNEL_PORT_LISTENER: 871 case SSH_CHANNEL_RPORT_LISTENER: 872 case SSH_CHANNEL_MUX_LISTENER: 873 case SSH_CHANNEL_CLOSED: 874 case SSH_CHANNEL_AUTH_SOCKET: 875 case SSH_CHANNEL_DYNAMIC: 876 case SSH_CHANNEL_RDYNAMIC_OPEN: 877 case SSH_CHANNEL_CONNECTING: 878 case SSH_CHANNEL_ZOMBIE: 879 case SSH_CHANNEL_ABANDONED: 880 case SSH_CHANNEL_UNIX_LISTENER: 881 case SSH_CHANNEL_RUNIX_LISTENER: 882 continue; 883 case SSH_CHANNEL_LARVAL: 884 continue; 885 case SSH_CHANNEL_OPENING: 886 case SSH_CHANNEL_OPEN: 887 case SSH_CHANNEL_RDYNAMIC_FINISH: 888 case SSH_CHANNEL_X11_OPEN: 889 case SSH_CHANNEL_MUX_CLIENT: 890 case SSH_CHANNEL_MUX_PROXY: 891 return 1; 892 default: 893 fatal_f("bad channel type %d", c->type); 894 /* NOTREACHED */ 895 } 896 } 897 return 0; 898 } 899 900 /* Returns the id of an open channel suitable for keepaliving */ 901 int 902 channel_find_open(struct ssh *ssh) 903 { 904 u_int i; 905 Channel *c; 906 907 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 908 c = ssh->chanctxt->channels[i]; 909 if (c == NULL || !c->have_remote_id) 910 continue; 911 switch (c->type) { 912 case SSH_CHANNEL_CLOSED: 913 case SSH_CHANNEL_DYNAMIC: 914 case SSH_CHANNEL_RDYNAMIC_OPEN: 915 case SSH_CHANNEL_RDYNAMIC_FINISH: 916 case SSH_CHANNEL_X11_LISTENER: 917 case SSH_CHANNEL_PORT_LISTENER: 918 case SSH_CHANNEL_RPORT_LISTENER: 919 case SSH_CHANNEL_MUX_LISTENER: 920 case SSH_CHANNEL_MUX_CLIENT: 921 case SSH_CHANNEL_MUX_PROXY: 922 case SSH_CHANNEL_OPENING: 923 case SSH_CHANNEL_CONNECTING: 924 case SSH_CHANNEL_ZOMBIE: 925 case SSH_CHANNEL_ABANDONED: 926 case SSH_CHANNEL_UNIX_LISTENER: 927 case SSH_CHANNEL_RUNIX_LISTENER: 928 continue; 929 case SSH_CHANNEL_LARVAL: 930 case SSH_CHANNEL_AUTH_SOCKET: 931 case SSH_CHANNEL_OPEN: 932 case SSH_CHANNEL_X11_OPEN: 933 return i; 934 default: 935 fatal_f("bad channel type %d", c->type); 936 /* NOTREACHED */ 937 } 938 } 939 return -1; 940 } 941 942 /* Returns the state of the channel's extended usage flag */ 943 const char * 944 channel_format_extended_usage(const Channel *c) 945 { 946 if (c->efd == -1) 947 return "closed"; 948 949 switch (c->extended_usage) { 950 case CHAN_EXTENDED_WRITE: 951 return "write"; 952 case CHAN_EXTENDED_READ: 953 return "read"; 954 case CHAN_EXTENDED_IGNORE: 955 return "ignore"; 956 default: 957 return "UNKNOWN"; 958 } 959 } 960 961 static char * 962 channel_format_status(const Channel *c) 963 { 964 char *ret = NULL; 965 966 xasprintf(&ret, "t%d [%s] %s%u i%u/%zu o%u/%zu e[%s]/%zu " 967 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 968 c->type, c->xctype != NULL ? c->xctype : c->ctype, 969 c->have_remote_id ? "r" : "nr", c->remote_id, 970 c->istate, sshbuf_len(c->input), 971 c->ostate, sshbuf_len(c->output), 972 channel_format_extended_usage(c), sshbuf_len(c->extended), 973 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 974 c->io_want, c->io_ready); 975 return ret; 976 } 977 978 /* 979 * Returns a message describing the currently open forwarded connections, 980 * suitable for sending to the client. The message contains crlf pairs for 981 * newlines. 982 */ 983 char * 984 channel_open_message(struct ssh *ssh) 985 { 986 struct sshbuf *buf; 987 Channel *c; 988 u_int i; 989 int r; 990 char *cp, *ret; 991 992 if ((buf = sshbuf_new()) == NULL) 993 fatal_f("sshbuf_new"); 994 if ((r = sshbuf_putf(buf, 995 "The following connections are open:\r\n")) != 0) 996 fatal_fr(r, "sshbuf_putf"); 997 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 998 c = ssh->chanctxt->channels[i]; 999 if (c == NULL) 1000 continue; 1001 switch (c->type) { 1002 case SSH_CHANNEL_X11_LISTENER: 1003 case SSH_CHANNEL_PORT_LISTENER: 1004 case SSH_CHANNEL_RPORT_LISTENER: 1005 case SSH_CHANNEL_CLOSED: 1006 case SSH_CHANNEL_AUTH_SOCKET: 1007 case SSH_CHANNEL_ZOMBIE: 1008 case SSH_CHANNEL_ABANDONED: 1009 case SSH_CHANNEL_MUX_LISTENER: 1010 case SSH_CHANNEL_UNIX_LISTENER: 1011 case SSH_CHANNEL_RUNIX_LISTENER: 1012 continue; 1013 case SSH_CHANNEL_LARVAL: 1014 case SSH_CHANNEL_OPENING: 1015 case SSH_CHANNEL_CONNECTING: 1016 case SSH_CHANNEL_DYNAMIC: 1017 case SSH_CHANNEL_RDYNAMIC_OPEN: 1018 case SSH_CHANNEL_RDYNAMIC_FINISH: 1019 case SSH_CHANNEL_OPEN: 1020 case SSH_CHANNEL_X11_OPEN: 1021 case SSH_CHANNEL_MUX_PROXY: 1022 case SSH_CHANNEL_MUX_CLIENT: 1023 cp = channel_format_status(c); 1024 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1025 c->self, c->remote_name, cp)) != 0) { 1026 free(cp); 1027 fatal_fr(r, "sshbuf_putf"); 1028 } 1029 free(cp); 1030 continue; 1031 default: 1032 fatal_f("bad channel type %d", c->type); 1033 /* NOTREACHED */ 1034 } 1035 } 1036 if ((ret = sshbuf_dup_string(buf)) == NULL) 1037 fatal_f("sshbuf_dup_string"); 1038 sshbuf_free(buf); 1039 return ret; 1040 } 1041 1042 static void 1043 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1044 { 1045 int r; 1046 1047 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1048 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1049 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1050 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1051 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1052 fatal_r(r, "%s: channel %i: open", where, c->self); 1053 } 1054 } 1055 1056 void 1057 channel_send_open(struct ssh *ssh, int id) 1058 { 1059 Channel *c = channel_lookup(ssh, id); 1060 int r; 1061 1062 if (c == NULL) { 1063 logit("channel_send_open: %d: bad id", id); 1064 return; 1065 } 1066 debug2("channel %d: send open", id); 1067 open_preamble(ssh, __func__, c, c->ctype); 1068 if ((r = sshpkt_send(ssh)) != 0) 1069 fatal_fr(r, "channel %i", c->self); 1070 } 1071 1072 void 1073 channel_request_start(struct ssh *ssh, int id, const char *service, 1074 int wantconfirm) 1075 { 1076 Channel *c = channel_lookup(ssh, id); 1077 int r; 1078 1079 if (c == NULL) { 1080 logit_f("%d: unknown channel id", id); 1081 return; 1082 } 1083 if (!c->have_remote_id) 1084 fatal_f("channel %d: no remote id", c->self); 1085 1086 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1087 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1088 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1089 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1090 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1091 fatal_fr(r, "channel %i", c->self); 1092 } 1093 } 1094 1095 void 1096 channel_register_status_confirm(struct ssh *ssh, int id, 1097 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1098 { 1099 struct channel_confirm *cc; 1100 Channel *c; 1101 1102 if ((c = channel_lookup(ssh, id)) == NULL) 1103 fatal_f("%d: bad id", id); 1104 1105 cc = xcalloc(1, sizeof(*cc)); 1106 cc->cb = cb; 1107 cc->abandon_cb = abandon_cb; 1108 cc->ctx = ctx; 1109 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1110 } 1111 1112 void 1113 channel_register_open_confirm(struct ssh *ssh, int id, 1114 channel_open_fn *fn, void *ctx) 1115 { 1116 Channel *c = channel_lookup(ssh, id); 1117 1118 if (c == NULL) { 1119 logit_f("%d: bad id", id); 1120 return; 1121 } 1122 c->open_confirm = fn; 1123 c->open_confirm_ctx = ctx; 1124 } 1125 1126 void 1127 channel_register_cleanup(struct ssh *ssh, int id, 1128 channel_callback_fn *fn, int do_close) 1129 { 1130 Channel *c = channel_by_id(ssh, id); 1131 1132 if (c == NULL) { 1133 logit_f("%d: bad id", id); 1134 return; 1135 } 1136 c->detach_user = fn; 1137 c->detach_close = do_close; 1138 } 1139 1140 void 1141 channel_cancel_cleanup(struct ssh *ssh, int id) 1142 { 1143 Channel *c = channel_by_id(ssh, id); 1144 1145 if (c == NULL) { 1146 logit_f("%d: bad id", id); 1147 return; 1148 } 1149 c->detach_user = NULL; 1150 c->detach_close = 0; 1151 } 1152 1153 void 1154 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1155 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1156 { 1157 Channel *c = channel_lookup(ssh, id); 1158 1159 if (c == NULL) { 1160 logit_f("%d: bad id", id); 1161 return; 1162 } 1163 c->input_filter = ifn; 1164 c->output_filter = ofn; 1165 c->filter_ctx = ctx; 1166 c->filter_cleanup = cfn; 1167 } 1168 1169 void 1170 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1171 int extusage, int nonblock, int is_tty, u_int window_max) 1172 { 1173 Channel *c = channel_lookup(ssh, id); 1174 int r; 1175 1176 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1177 fatal("channel_activate for non-larval channel %d.", id); 1178 if (!c->have_remote_id) 1179 fatal_f("channel %d: no remote id", c->self); 1180 1181 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1182 c->type = SSH_CHANNEL_OPEN; 1183 c->lastused = monotime(); 1184 c->local_window = c->local_window_max = window_max; 1185 1186 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1187 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1188 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1189 (r = sshpkt_send(ssh)) != 0) 1190 fatal_fr(r, "channel %i", c->self); 1191 } 1192 1193 static void 1194 channel_pre_listener(struct ssh *ssh, Channel *c) 1195 { 1196 c->io_want = SSH_CHAN_IO_SOCK_R; 1197 } 1198 1199 static void 1200 channel_pre_connecting(struct ssh *ssh, Channel *c) 1201 { 1202 debug3("channel %d: waiting for connection", c->self); 1203 c->io_want = SSH_CHAN_IO_SOCK_W; 1204 } 1205 1206 static int 1207 channel_tcpwinsz(struct ssh *ssh) 1208 { 1209 u_int32_t tcpwinsz = 0; 1210 socklen_t optsz = sizeof(tcpwinsz); 1211 int ret = -1; 1212 1213 /* if we aren't on a socket return 128KB*/ 1214 if(!ssh_packet_connection_is_on_socket(ssh)) 1215 return(128*1024); 1216 ret = getsockopt(ssh_packet_get_connection_in(ssh), 1217 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz); 1218 /* return no more than SSHBUF_SIZE_MAX (currently 256MB) */ 1219 if ((ret == 0) && tcpwinsz > SSHBUF_SIZE_MAX) 1220 tcpwinsz = SSHBUF_SIZE_MAX; 1221 debug2("tcpwinsz: %d for connection: %d", tcpwinsz, 1222 ssh_packet_get_connection_in(ssh)); 1223 return(tcpwinsz); 1224 } 1225 1226 static void 1227 channel_pre_open(struct ssh *ssh, Channel *c) 1228 { 1229 c->io_want = 0; 1230 if (c->istate == CHAN_INPUT_OPEN && 1231 c->remote_window > 0 && 1232 sshbuf_len(c->input) < c->remote_window && 1233 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1234 c->io_want |= SSH_CHAN_IO_RFD; 1235 if (c->ostate == CHAN_OUTPUT_OPEN || 1236 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1237 if (sshbuf_len(c->output) > 0) { 1238 c->io_want |= SSH_CHAN_IO_WFD; 1239 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1240 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1241 debug2("channel %d: " 1242 "obuf_empty delayed efd %d/(%zu)", c->self, 1243 c->efd, sshbuf_len(c->extended)); 1244 else 1245 chan_obuf_empty(ssh, c); 1246 } 1247 } 1248 /** XXX check close conditions, too */ 1249 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1250 c->ostate == CHAN_OUTPUT_CLOSED)) { 1251 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1252 sshbuf_len(c->extended) > 0) 1253 c->io_want |= SSH_CHAN_IO_EFD_W; 1254 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1255 (c->extended_usage == CHAN_EXTENDED_READ || 1256 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1257 sshbuf_len(c->extended) < c->remote_window) 1258 c->io_want |= SSH_CHAN_IO_EFD_R; 1259 } 1260 /* XXX: What about efd? races? */ 1261 } 1262 1263 /* 1264 * This is a special state for X11 authentication spoofing. An opened X11 1265 * connection (when authentication spoofing is being done) remains in this 1266 * state until the first packet has been completely read. The authentication 1267 * data in that packet is then substituted by the real data if it matches the 1268 * fake data, and the channel is put into normal mode. 1269 * XXX All this happens at the client side. 1270 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1271 */ 1272 static int 1273 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1274 { 1275 struct ssh_channels *sc = ssh->chanctxt; 1276 u_char *ucp; 1277 u_int proto_len, data_len; 1278 1279 /* Is this being called after the refusal deadline? */ 1280 if (sc->x11_refuse_time != 0 && 1281 monotime() >= sc->x11_refuse_time) { 1282 verbose("Rejected X11 connection after ForwardX11Timeout " 1283 "expired"); 1284 return -1; 1285 } 1286 1287 /* Check if the fixed size part of the packet is in buffer. */ 1288 if (sshbuf_len(b) < 12) 1289 return 0; 1290 1291 /* Parse the lengths of variable-length fields. */ 1292 ucp = sshbuf_mutable_ptr(b); 1293 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1294 proto_len = 256 * ucp[6] + ucp[7]; 1295 data_len = 256 * ucp[8] + ucp[9]; 1296 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1297 proto_len = ucp[6] + 256 * ucp[7]; 1298 data_len = ucp[8] + 256 * ucp[9]; 1299 } else { 1300 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1301 ucp[0]); 1302 return -1; 1303 } 1304 1305 /* Check if the whole packet is in buffer. */ 1306 if (sshbuf_len(b) < 1307 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1308 return 0; 1309 1310 /* Check if authentication protocol matches. */ 1311 if (proto_len != strlen(sc->x11_saved_proto) || 1312 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1313 debug2("X11 connection uses different authentication protocol."); 1314 return -1; 1315 } 1316 /* Check if authentication data matches our fake data. */ 1317 if (data_len != sc->x11_fake_data_len || 1318 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1319 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1320 debug2("X11 auth data does not match fake data."); 1321 return -1; 1322 } 1323 /* Check fake data length */ 1324 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1325 error("X11 fake_data_len %d != saved_data_len %d", 1326 sc->x11_fake_data_len, sc->x11_saved_data_len); 1327 return -1; 1328 } 1329 /* 1330 * Received authentication protocol and data match 1331 * our fake data. Substitute the fake data with real 1332 * data. 1333 */ 1334 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1335 sc->x11_saved_data, sc->x11_saved_data_len); 1336 return 1; 1337 } 1338 1339 void 1340 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1341 { 1342 debug3_f("channel %d: forcibly closing", c->self); 1343 if (c->istate == CHAN_INPUT_OPEN) 1344 chan_read_failed(ssh, c); 1345 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1346 sshbuf_reset(c->input); 1347 chan_ibuf_empty(ssh, c); 1348 } 1349 if (c->ostate == CHAN_OUTPUT_OPEN || 1350 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1351 sshbuf_reset(c->output); 1352 chan_write_failed(ssh, c); 1353 } 1354 if (c->detach_user) 1355 c->detach_user(ssh, c->self, 1, NULL); 1356 if (c->efd != -1) 1357 channel_close_fd(ssh, c, &c->efd); 1358 if (abandon) 1359 c->type = SSH_CHANNEL_ABANDONED; 1360 /* exempt from inactivity timeouts */ 1361 c->inactive_deadline = 0; 1362 c->lastused = 0; 1363 } 1364 1365 static void 1366 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1367 { 1368 int ret = x11_open_helper(ssh, c->output); 1369 1370 /* c->force_drain = 1; */ 1371 1372 if (ret == 1) { 1373 c->type = SSH_CHANNEL_OPEN; 1374 c->lastused = monotime(); 1375 channel_pre_open(ssh, c); 1376 } else if (ret == -1) { 1377 logit("X11 connection rejected because of wrong " 1378 "authentication."); 1379 debug2("X11 rejected %d i%d/o%d", 1380 c->self, c->istate, c->ostate); 1381 channel_force_close(ssh, c, 0); 1382 } 1383 } 1384 1385 static void 1386 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1387 { 1388 c->io_want = 0; 1389 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1390 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1391 c->io_want |= SSH_CHAN_IO_RFD; 1392 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1393 /* clear buffer immediately (discard any partial packet) */ 1394 sshbuf_reset(c->input); 1395 chan_ibuf_empty(ssh, c); 1396 /* Start output drain. XXX just kill chan? */ 1397 chan_rcvd_oclose(ssh, c); 1398 } 1399 if (c->ostate == CHAN_OUTPUT_OPEN || 1400 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1401 if (sshbuf_len(c->output) > 0) 1402 c->io_want |= SSH_CHAN_IO_WFD; 1403 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1404 chan_obuf_empty(ssh, c); 1405 } 1406 } 1407 1408 /* try to decode a socks4 header */ 1409 static int 1410 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1411 { 1412 const u_char *p; 1413 char *host; 1414 u_int len, have, i, found, need; 1415 char username[256]; 1416 struct { 1417 u_int8_t version; 1418 u_int8_t command; 1419 u_int16_t dest_port; 1420 struct in_addr dest_addr; 1421 } s4_req, s4_rsp; 1422 int r; 1423 1424 debug2("channel %d: decode socks4", c->self); 1425 1426 have = sshbuf_len(input); 1427 len = sizeof(s4_req); 1428 if (have < len) 1429 return 0; 1430 p = sshbuf_ptr(input); 1431 1432 need = 1; 1433 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1434 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1435 debug2("channel %d: socks4a request", c->self); 1436 /* ... and needs an extra string (the hostname) */ 1437 need = 2; 1438 } 1439 /* Check for terminating NUL on the string(s) */ 1440 for (found = 0, i = len; i < have; i++) { 1441 if (p[i] == '\0') { 1442 found++; 1443 if (found == need) 1444 break; 1445 } 1446 if (i > 1024) { 1447 /* the peer is probably sending garbage */ 1448 debug("channel %d: decode socks4: too long", 1449 c->self); 1450 return -1; 1451 } 1452 } 1453 if (found < need) 1454 return 0; 1455 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1456 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1457 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1458 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1459 debug_r(r, "channels %d: decode socks4", c->self); 1460 return -1; 1461 } 1462 have = sshbuf_len(input); 1463 p = sshbuf_ptr(input); 1464 if (memchr(p, '\0', have) == NULL) { 1465 error("channel %d: decode socks4: unterminated user", c->self); 1466 return -1; 1467 } 1468 len = strlen(p); 1469 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1470 len++; /* trailing '\0' */ 1471 strlcpy(username, p, sizeof(username)); 1472 if ((r = sshbuf_consume(input, len)) != 0) 1473 fatal_fr(r, "channel %d: consume", c->self); 1474 free(c->path); 1475 c->path = NULL; 1476 if (need == 1) { /* SOCKS4: one string */ 1477 host = inet_ntoa(s4_req.dest_addr); 1478 c->path = xstrdup(host); 1479 } else { /* SOCKS4A: two strings */ 1480 have = sshbuf_len(input); 1481 p = sshbuf_ptr(input); 1482 if (memchr(p, '\0', have) == NULL) { 1483 error("channel %d: decode socks4a: host not nul " 1484 "terminated", c->self); 1485 return -1; 1486 } 1487 len = strlen(p); 1488 debug2("channel %d: decode socks4a: host %s/%d", 1489 c->self, p, len); 1490 len++; /* trailing '\0' */ 1491 if (len > NI_MAXHOST) { 1492 error("channel %d: hostname \"%.100s\" too long", 1493 c->self, p); 1494 return -1; 1495 } 1496 c->path = xstrdup(p); 1497 if ((r = sshbuf_consume(input, len)) != 0) 1498 fatal_fr(r, "channel %d: consume", c->self); 1499 } 1500 c->host_port = ntohs(s4_req.dest_port); 1501 1502 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1503 c->self, c->path, c->host_port, s4_req.command); 1504 1505 if (s4_req.command != 1) { 1506 debug("channel %d: cannot handle: %s cn %d", 1507 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1508 return -1; 1509 } 1510 s4_rsp.version = 0; /* vn: 0 for reply */ 1511 s4_rsp.command = 90; /* cd: req granted */ 1512 s4_rsp.dest_port = 0; /* ignored */ 1513 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1514 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1515 fatal_fr(r, "channel %d: append reply", c->self); 1516 return 1; 1517 } 1518 1519 /* try to decode a socks5 header */ 1520 #define SSH_SOCKS5_AUTHDONE 0x1000 1521 #define SSH_SOCKS5_NOAUTH 0x00 1522 #define SSH_SOCKS5_IPV4 0x01 1523 #define SSH_SOCKS5_DOMAIN 0x03 1524 #define SSH_SOCKS5_IPV6 0x04 1525 #define SSH_SOCKS5_CONNECT 0x01 1526 #define SSH_SOCKS5_SUCCESS 0x00 1527 1528 static int 1529 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1530 { 1531 /* XXX use get/put_u8 instead of trusting struct padding */ 1532 struct { 1533 u_int8_t version; 1534 u_int8_t command; 1535 u_int8_t reserved; 1536 u_int8_t atyp; 1537 } s5_req, s5_rsp; 1538 u_int16_t dest_port; 1539 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1540 const u_char *p; 1541 u_int have, need, i, found, nmethods, addrlen, af; 1542 int r; 1543 1544 debug2("channel %d: decode socks5", c->self); 1545 p = sshbuf_ptr(input); 1546 if (p[0] != 0x05) 1547 return -1; 1548 have = sshbuf_len(input); 1549 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1550 /* format: ver | nmethods | methods */ 1551 if (have < 2) 1552 return 0; 1553 nmethods = p[1]; 1554 if (have < nmethods + 2) 1555 return 0; 1556 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1557 for (found = 0, i = 2; i < nmethods + 2; i++) { 1558 if (p[i] == SSH_SOCKS5_NOAUTH) { 1559 found = 1; 1560 break; 1561 } 1562 } 1563 if (!found) { 1564 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1565 c->self); 1566 return -1; 1567 } 1568 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1569 fatal_fr(r, "channel %d: consume", c->self); 1570 /* version, method */ 1571 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1572 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1573 fatal_fr(r, "channel %d: append reply", c->self); 1574 c->flags |= SSH_SOCKS5_AUTHDONE; 1575 debug2("channel %d: socks5 auth done", c->self); 1576 return 0; /* need more */ 1577 } 1578 debug2("channel %d: socks5 post auth", c->self); 1579 if (have < sizeof(s5_req)+1) 1580 return 0; /* need more */ 1581 memcpy(&s5_req, p, sizeof(s5_req)); 1582 if (s5_req.version != 0x05 || 1583 s5_req.command != SSH_SOCKS5_CONNECT || 1584 s5_req.reserved != 0x00) { 1585 debug2("channel %d: only socks5 connect supported", c->self); 1586 return -1; 1587 } 1588 switch (s5_req.atyp){ 1589 case SSH_SOCKS5_IPV4: 1590 addrlen = 4; 1591 af = AF_INET; 1592 break; 1593 case SSH_SOCKS5_DOMAIN: 1594 addrlen = p[sizeof(s5_req)]; 1595 af = -1; 1596 break; 1597 case SSH_SOCKS5_IPV6: 1598 addrlen = 16; 1599 af = AF_INET6; 1600 break; 1601 default: 1602 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1603 return -1; 1604 } 1605 need = sizeof(s5_req) + addrlen + 2; 1606 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1607 need++; 1608 if (have < need) 1609 return 0; 1610 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1611 fatal_fr(r, "channel %d: consume", c->self); 1612 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1613 /* host string length */ 1614 if ((r = sshbuf_consume(input, 1)) != 0) 1615 fatal_fr(r, "channel %d: consume", c->self); 1616 } 1617 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1618 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1619 debug_r(r, "channel %d: parse addr/port", c->self); 1620 return -1; 1621 } 1622 dest_addr[addrlen] = '\0'; 1623 free(c->path); 1624 c->path = NULL; 1625 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1626 if (addrlen >= NI_MAXHOST) { 1627 error("channel %d: dynamic request: socks5 hostname " 1628 "\"%.100s\" too long", c->self, dest_addr); 1629 return -1; 1630 } 1631 c->path = xstrdup(dest_addr); 1632 } else { 1633 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1634 return -1; 1635 c->path = xstrdup(ntop); 1636 } 1637 c->host_port = ntohs(dest_port); 1638 1639 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1640 c->self, c->path, c->host_port, s5_req.command); 1641 1642 s5_rsp.version = 0x05; 1643 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1644 s5_rsp.reserved = 0; /* ignored */ 1645 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1646 dest_port = 0; /* ignored */ 1647 1648 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1649 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1650 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1651 fatal_fr(r, "channel %d: append reply", c->self); 1652 return 1; 1653 } 1654 1655 Channel * 1656 channel_connect_stdio_fwd(struct ssh *ssh, 1657 const char *host_to_connect, u_short port_to_connect, 1658 int in, int out, int nonblock) 1659 { 1660 Channel *c; 1661 1662 debug_f("%s:%d", host_to_connect, port_to_connect); 1663 1664 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1665 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1666 0, "stdio-forward", nonblock); 1667 1668 c->path = xstrdup(host_to_connect); 1669 c->host_port = port_to_connect; 1670 c->listening_port = 0; 1671 c->force_drain = 1; 1672 1673 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1674 port_open_helper(ssh, c, "direct-tcpip"); 1675 1676 return c; 1677 } 1678 1679 /* dynamic port forwarding */ 1680 static void 1681 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1682 { 1683 const u_char *p; 1684 u_int have; 1685 int ret; 1686 1687 c->io_want = 0; 1688 have = sshbuf_len(c->input); 1689 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1690 /* sshbuf_dump(c->input, stderr); */ 1691 /* check if the fixed size part of the packet is in buffer. */ 1692 if (have < 3) { 1693 /* need more */ 1694 c->io_want |= SSH_CHAN_IO_RFD; 1695 return; 1696 } 1697 /* try to guess the protocol */ 1698 p = sshbuf_ptr(c->input); 1699 /* XXX sshbuf_peek_u8? */ 1700 switch (p[0]) { 1701 case 0x04: 1702 ret = channel_decode_socks4(c, c->input, c->output); 1703 break; 1704 case 0x05: 1705 ret = channel_decode_socks5(c, c->input, c->output); 1706 break; 1707 default: 1708 ret = -1; 1709 break; 1710 } 1711 if (ret < 0) { 1712 chan_mark_dead(ssh, c); 1713 } else if (ret == 0) { 1714 debug2("channel %d: pre_dynamic: need more", c->self); 1715 /* need more */ 1716 c->io_want |= SSH_CHAN_IO_RFD; 1717 if (sshbuf_len(c->output)) 1718 c->io_want |= SSH_CHAN_IO_WFD; 1719 } else { 1720 /* switch to the next state */ 1721 c->type = SSH_CHANNEL_OPENING; 1722 port_open_helper(ssh, c, "direct-tcpip"); 1723 } 1724 } 1725 1726 /* simulate read-error */ 1727 static void 1728 rdynamic_close(struct ssh *ssh, Channel *c) 1729 { 1730 c->type = SSH_CHANNEL_OPEN; 1731 channel_force_close(ssh, c, 0); 1732 } 1733 1734 /* reverse dynamic port forwarding */ 1735 static void 1736 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1737 { 1738 const u_char *p; 1739 u_int have, len; 1740 int r, ret; 1741 1742 have = sshbuf_len(c->output); 1743 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1744 /* sshbuf_dump(c->output, stderr); */ 1745 /* EOF received */ 1746 if (c->flags & CHAN_EOF_RCVD) { 1747 if ((r = sshbuf_consume(c->output, have)) != 0) 1748 fatal_fr(r, "channel %d: consume", c->self); 1749 rdynamic_close(ssh, c); 1750 return; 1751 } 1752 /* check if the fixed size part of the packet is in buffer. */ 1753 if (have < 3) 1754 return; 1755 /* try to guess the protocol */ 1756 p = sshbuf_ptr(c->output); 1757 switch (p[0]) { 1758 case 0x04: 1759 /* switch input/output for reverse forwarding */ 1760 ret = channel_decode_socks4(c, c->output, c->input); 1761 break; 1762 case 0x05: 1763 ret = channel_decode_socks5(c, c->output, c->input); 1764 break; 1765 default: 1766 ret = -1; 1767 break; 1768 } 1769 if (ret < 0) { 1770 rdynamic_close(ssh, c); 1771 } else if (ret == 0) { 1772 debug2("channel %d: pre_rdynamic: need more", c->self); 1773 /* send socks request to peer */ 1774 len = sshbuf_len(c->input); 1775 if (len > 0 && len < c->remote_window) { 1776 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1777 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1778 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1779 (r = sshpkt_send(ssh)) != 0) { 1780 fatal_fr(r, "channel %i: rdynamic", c->self); 1781 } 1782 if ((r = sshbuf_consume(c->input, len)) != 0) 1783 fatal_fr(r, "channel %d: consume", c->self); 1784 c->remote_window -= len; 1785 } 1786 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1787 /* the connect failed */ 1788 rdynamic_close(ssh, c); 1789 } 1790 } 1791 1792 /* This is our fake X11 server socket. */ 1793 static void 1794 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1795 { 1796 Channel *nc; 1797 struct sockaddr_storage addr; 1798 int r, newsock, oerrno, remote_port; 1799 socklen_t addrlen; 1800 char buf[16384], *remote_ipaddr; 1801 1802 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1803 return; 1804 1805 debug("X11 connection requested."); 1806 addrlen = sizeof(addr); 1807 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1808 if (c->single_connection) { 1809 oerrno = errno; 1810 debug2("single_connection: closing X11 listener."); 1811 channel_close_fd(ssh, c, &c->sock); 1812 chan_mark_dead(ssh, c); 1813 errno = oerrno; 1814 } 1815 if (newsock == -1) { 1816 if (errno != EINTR && errno != EWOULDBLOCK && 1817 errno != ECONNABORTED) 1818 error("accept: %.100s", strerror(errno)); 1819 if (errno == EMFILE || errno == ENFILE) 1820 c->notbefore = monotime() + 1; 1821 return; 1822 } 1823 set_nodelay(newsock); 1824 remote_ipaddr = get_peer_ipaddr(newsock); 1825 remote_port = get_peer_port(newsock); 1826 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1827 remote_ipaddr, remote_port); 1828 1829 nc = channel_new(ssh, "x11-connection", 1830 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1831 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1832 open_preamble(ssh, __func__, nc, "x11"); 1833 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1834 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1835 fatal_fr(r, "channel %i: reply", c->self); 1836 } 1837 if ((r = sshpkt_send(ssh)) != 0) 1838 fatal_fr(r, "channel %i: send", c->self); 1839 free(remote_ipaddr); 1840 } 1841 1842 static void 1843 port_open_helper(struct ssh *ssh, Channel *c, const char *rtype) 1844 { 1845 char *local_ipaddr = get_local_ipaddr(c->sock); 1846 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1847 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1848 int remote_port = get_peer_port(c->sock); 1849 int r; 1850 1851 if (remote_port == -1) { 1852 /* Fake addr/port to appease peers that validate it (Tectia) */ 1853 free(remote_ipaddr); 1854 remote_ipaddr = xstrdup("127.0.0.1"); 1855 remote_port = 65535; 1856 } 1857 1858 free(c->remote_name); 1859 xasprintf(&c->remote_name, 1860 "%s: listening port %d for %.100s port %d, " 1861 "connect from %.200s port %d to %.100s port %d", 1862 rtype, c->listening_port, c->path, c->host_port, 1863 remote_ipaddr, remote_port, local_ipaddr, local_port); 1864 1865 open_preamble(ssh, __func__, c, rtype); 1866 if (strcmp(rtype, "direct-tcpip") == 0) { 1867 /* target host, port */ 1868 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1869 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1870 fatal_fr(r, "channel %i: reply", c->self); 1871 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1872 /* target path */ 1873 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1874 fatal_fr(r, "channel %i: reply", c->self); 1875 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1876 /* listen path */ 1877 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1878 fatal_fr(r, "channel %i: reply", c->self); 1879 } else { 1880 /* listen address, port */ 1881 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1882 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1883 fatal_fr(r, "channel %i: reply", c->self); 1884 } 1885 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1886 /* reserved for future owner/mode info */ 1887 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1888 fatal_fr(r, "channel %i: reply", c->self); 1889 } else { 1890 /* originator host and port */ 1891 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1892 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1893 fatal_fr(r, "channel %i: reply", c->self); 1894 } 1895 if ((r = sshpkt_send(ssh)) != 0) 1896 fatal_fr(r, "channel %i: send", c->self); 1897 free(remote_ipaddr); 1898 free(local_ipaddr); 1899 } 1900 1901 void 1902 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1903 { 1904 ssh->chanctxt->x11_refuse_time = refuse_time; 1905 } 1906 1907 /* 1908 * This socket is listening for connections to a forwarded TCP/IP port. 1909 */ 1910 static void 1911 channel_post_port_listener(struct ssh *ssh, Channel *c) 1912 { 1913 Channel *nc; 1914 struct sockaddr_storage addr; 1915 int newsock, nextstate; 1916 socklen_t addrlen; 1917 const char *rtype; 1918 1919 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1920 return; 1921 1922 debug("Connection to port %d forwarding to %.100s port %d requested.", 1923 c->listening_port, c->path, c->host_port); 1924 1925 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1926 nextstate = SSH_CHANNEL_OPENING; 1927 rtype = "forwarded-tcpip"; 1928 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1929 nextstate = SSH_CHANNEL_OPENING; 1930 rtype = "forwarded-streamlocal@openssh.com"; 1931 } else if (c->host_port == PORT_STREAMLOCAL) { 1932 nextstate = SSH_CHANNEL_OPENING; 1933 rtype = "direct-streamlocal@openssh.com"; 1934 } else if (c->host_port == 0) { 1935 nextstate = SSH_CHANNEL_DYNAMIC; 1936 rtype = "dynamic-tcpip"; 1937 } else { 1938 nextstate = SSH_CHANNEL_OPENING; 1939 rtype = "direct-tcpip"; 1940 } 1941 1942 addrlen = sizeof(addr); 1943 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1944 if (newsock == -1) { 1945 if (errno != EINTR && errno != EWOULDBLOCK && 1946 errno != ECONNABORTED) 1947 error("accept: %.100s", strerror(errno)); 1948 if (errno == EMFILE || errno == ENFILE) 1949 c->notbefore = monotime() + 1; 1950 return; 1951 } 1952 if (c->host_port != PORT_STREAMLOCAL) 1953 set_nodelay(newsock); 1954 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1955 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1956 nc->listening_port = c->listening_port; 1957 nc->host_port = c->host_port; 1958 if (c->path != NULL) 1959 nc->path = xstrdup(c->path); 1960 1961 if (nextstate != SSH_CHANNEL_DYNAMIC) 1962 port_open_helper(ssh, nc, rtype); 1963 } 1964 1965 /* 1966 * This is the authentication agent socket listening for connections from 1967 * clients. 1968 */ 1969 static void 1970 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1971 { 1972 Channel *nc; 1973 int r, newsock; 1974 struct sockaddr_storage addr; 1975 socklen_t addrlen; 1976 1977 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1978 return; 1979 1980 addrlen = sizeof(addr); 1981 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1982 if (newsock == -1) { 1983 error("accept from auth socket: %.100s", strerror(errno)); 1984 if (errno == EMFILE || errno == ENFILE) 1985 c->notbefore = monotime() + 1; 1986 return; 1987 } 1988 nc = channel_new(ssh, "agent-connection", 1989 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1990 c->local_window_max, c->local_maxpacket, 1991 0, "accepted auth socket", 1); 1992 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1993 if ((r = sshpkt_send(ssh)) != 0) 1994 fatal_fr(r, "channel %i", c->self); 1995 } 1996 1997 static void 1998 channel_post_connecting(struct ssh *ssh, Channel *c) 1999 { 2000 int err = 0, sock, isopen, r; 2001 socklen_t sz = sizeof(err); 2002 2003 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2004 return; 2005 if (!c->have_remote_id) 2006 fatal_f("channel %d: no remote id", c->self); 2007 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2008 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2009 2010 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2011 err = errno; 2012 error("getsockopt SO_ERROR failed"); 2013 } 2014 2015 if (err == 0) { 2016 /* Non-blocking connection completed */ 2017 debug("channel %d: connected to %s port %d", 2018 c->self, c->connect_ctx.host, c->connect_ctx.port); 2019 channel_connect_ctx_free(&c->connect_ctx); 2020 c->type = SSH_CHANNEL_OPEN; 2021 c->lastused = monotime(); 2022 if (isopen) { 2023 /* no message necessary */ 2024 } else { 2025 if ((r = sshpkt_start(ssh, 2026 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2027 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2028 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2029 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2030 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2031 (r = sshpkt_send(ssh)) != 0) 2032 fatal_fr(r, "channel %i open confirm", c->self); 2033 } 2034 return; 2035 } 2036 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2037 return; 2038 2039 /* Non-blocking connection failed */ 2040 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2041 2042 /* Try next address, if any */ 2043 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2044 /* Exhausted all addresses for this destination */ 2045 error("connect_to %.100s port %d: failed.", 2046 c->connect_ctx.host, c->connect_ctx.port); 2047 channel_connect_ctx_free(&c->connect_ctx); 2048 if (isopen) { 2049 rdynamic_close(ssh, c); 2050 } else { 2051 if ((r = sshpkt_start(ssh, 2052 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2053 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2054 (r = sshpkt_put_u32(ssh, 2055 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2056 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2057 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2058 (r = sshpkt_send(ssh)) != 0) 2059 fatal_fr(r, "channel %i: failure", c->self); 2060 chan_mark_dead(ssh, c); 2061 } 2062 } 2063 2064 /* New non-blocking connection in progress */ 2065 close(c->sock); 2066 c->sock = c->rfd = c->wfd = sock; 2067 } 2068 2069 static int 2070 channel_handle_rfd(struct ssh *ssh, Channel *c) 2071 { 2072 char buf[CHAN_RBUF]; 2073 ssize_t len; 2074 int r; 2075 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2076 2077 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2078 return 1; /* Shouldn't happen */ 2079 if ((avail = sshbuf_avail(c->input)) == 0) 2080 return 1; /* Shouldn't happen */ 2081 2082 /* 2083 * For "simple" channels (i.e. not datagram or filtered), we can 2084 * read directly to the channel buffer. 2085 */ 2086 if (c->input_filter == NULL && !c->datagram) { 2087 /* Only OPEN channels have valid rwin */ 2088 if (c->type == SSH_CHANNEL_OPEN) { 2089 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2090 return 1; /* shouldn't happen */ 2091 if (maxlen > c->remote_window - have) 2092 maxlen = c->remote_window - have; 2093 } 2094 if (maxlen > avail) 2095 maxlen = avail; 2096 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2097 if (errno == EINTR || errno == EAGAIN) 2098 return 1; 2099 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2100 c->self, c->rfd, maxlen, ssh_err(r)); 2101 goto rfail; 2102 } 2103 if (nr != 0) 2104 c->lastused = monotime(); 2105 return 1; 2106 } 2107 2108 len = read(c->rfd, buf, sizeof(buf)); 2109 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2110 return 1; 2111 if (len <= 0) { 2112 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2113 c->self, c->rfd, len, 2114 len == 0 ? "closed" : strerror(errno)); 2115 rfail: 2116 if (c->type != SSH_CHANNEL_OPEN) { 2117 debug2("channel %d: not open", c->self); 2118 chan_mark_dead(ssh, c); 2119 return -1; 2120 } else { 2121 chan_read_failed(ssh, c); 2122 } 2123 return -1; 2124 } 2125 c->lastused = monotime(); 2126 if (c->input_filter != NULL) { 2127 if (c->input_filter(ssh, c, buf, len) == -1) { 2128 debug2("channel %d: filter stops", c->self); 2129 chan_read_failed(ssh, c); 2130 } 2131 } else if (c->datagram) { 2132 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2133 fatal_fr(r, "channel %i: put datagram", c->self); 2134 } 2135 return 1; 2136 } 2137 2138 static int 2139 channel_handle_wfd(struct ssh *ssh, Channel *c) 2140 { 2141 struct termios tio; 2142 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2143 size_t dlen, olen = 0; 2144 int r, len; 2145 2146 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2147 return 1; 2148 if (sshbuf_len(c->output) == 0) 2149 return 1; 2150 2151 /* Send buffered output data to the socket. */ 2152 olen = sshbuf_len(c->output); 2153 if (c->output_filter != NULL) { 2154 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2155 debug2("channel %d: filter stops", c->self); 2156 if (c->type != SSH_CHANNEL_OPEN) 2157 chan_mark_dead(ssh, c); 2158 else 2159 chan_write_failed(ssh, c); 2160 return -1; 2161 } 2162 } else if (c->datagram) { 2163 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2164 fatal_fr(r, "channel %i: get datagram", c->self); 2165 buf = data; 2166 } else { 2167 buf = data = sshbuf_mutable_ptr(c->output); 2168 dlen = sshbuf_len(c->output); 2169 } 2170 2171 if (c->datagram) { 2172 /* ignore truncated writes, datagrams might get lost */ 2173 len = write(c->wfd, buf, dlen); 2174 free(data); 2175 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2176 return 1; 2177 if (len <= 0) 2178 goto write_fail; 2179 goto out; 2180 } 2181 2182 len = write(c->wfd, buf, dlen); 2183 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2184 return 1; 2185 if (len <= 0) { 2186 write_fail: 2187 if (c->type != SSH_CHANNEL_OPEN) { 2188 debug2("channel %d: not open", c->self); 2189 chan_mark_dead(ssh, c); 2190 return -1; 2191 } else { 2192 chan_write_failed(ssh, c); 2193 } 2194 return -1; 2195 } 2196 c->lastused = monotime(); 2197 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2198 if (tcgetattr(c->wfd, &tio) == 0 && 2199 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2200 /* 2201 * Simulate echo to reduce the impact of 2202 * traffic analysis. We need to match the 2203 * size of a SSH2_MSG_CHANNEL_DATA message 2204 * (4 byte channel id + buf) 2205 */ 2206 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2207 (r = sshpkt_send(ssh)) != 0) 2208 fatal_fr(r, "channel %i: ignore", c->self); 2209 } 2210 } 2211 if ((r = sshbuf_consume(c->output, len)) != 0) 2212 fatal_fr(r, "channel %i: consume", c->self); 2213 out: 2214 c->local_consumed += olen - sshbuf_len(c->output); 2215 2216 return 1; 2217 } 2218 2219 static int 2220 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2221 { 2222 int r; 2223 ssize_t len; 2224 2225 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2226 return 1; 2227 if (sshbuf_len(c->extended) == 0) 2228 return 1; 2229 2230 len = write(c->efd, sshbuf_ptr(c->extended), 2231 sshbuf_len(c->extended)); 2232 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2233 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2234 return 1; 2235 if (len <= 0) { 2236 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2237 channel_close_fd(ssh, c, &c->efd); 2238 } else { 2239 if ((r = sshbuf_consume(c->extended, len)) != 0) 2240 fatal_fr(r, "channel %i: consume", c->self); 2241 c->local_consumed += len; 2242 c->lastused = monotime(); 2243 } 2244 return 1; 2245 } 2246 2247 static int 2248 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2249 { 2250 char buf[CHAN_RBUF]; 2251 int r; 2252 ssize_t len; 2253 2254 if ((c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2255 return 1; 2256 2257 len = read(c->efd, buf, sizeof(buf)); 2258 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2259 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2260 return 1; 2261 if (len <= 0) { 2262 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2263 channel_close_fd(ssh, c, &c->efd); 2264 return 1; 2265 } 2266 c->lastused = monotime(); 2267 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2268 debug3("channel %d: discard efd", c->self); 2269 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2270 fatal_fr(r, "channel %i: append", c->self); 2271 return 1; 2272 } 2273 2274 static int 2275 channel_handle_efd(struct ssh *ssh, Channel *c) 2276 { 2277 if (c->efd == -1) 2278 return 1; 2279 2280 /** XXX handle drain efd, too */ 2281 2282 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2283 return channel_handle_efd_write(ssh, c); 2284 else if (c->extended_usage == CHAN_EXTENDED_READ || 2285 c->extended_usage == CHAN_EXTENDED_IGNORE) 2286 return channel_handle_efd_read(ssh, c); 2287 2288 return 1; 2289 } 2290 2291 static int 2292 channel_check_window(struct ssh *ssh, Channel *c) 2293 { 2294 int r; 2295 2296 if (c->type == SSH_CHANNEL_OPEN && 2297 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2298 ((c->local_window_max - c->local_window > 2299 c->local_maxpacket*3) || 2300 c->local_window < c->local_window_max/2) && 2301 c->local_consumed > 0) { 2302 u_int addition = 0; 2303 u_int32_t tcpwinsz = channel_tcpwinsz(ssh); 2304 /* adjust max window size if we are in a dynamic environment */ 2305 if (c->dynamic_window && (tcpwinsz > c->local_window_max)) { 2306 /* grow the window somewhat aggressively to maintain 2307 * pressure */ 2308 addition = 1.5*(tcpwinsz - c->local_window_max); 2309 c->local_window_max += addition; 2310 debug("Channel: Window growth to %d by %d bytes", c->local_window_max, addition); 2311 } 2312 if (!c->have_remote_id) 2313 fatal_f("channel %d: no remote id", c->self); 2314 if ((r = sshpkt_start(ssh, 2315 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2316 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2317 (r = sshpkt_put_u32(ssh, c->local_consumed + addition)) != 0 || 2318 (r = sshpkt_send(ssh)) != 0) { 2319 fatal_fr(r, "channel %i", c->self); 2320 } 2321 debug2("channel %d: window %d sent adjust %d", c->self, 2322 c->local_window, 2323 c->local_consumed + addition); 2324 c->local_window += c->local_consumed + addition; 2325 c->local_consumed = 0; 2326 } 2327 return 1; 2328 } 2329 2330 static void 2331 channel_post_open(struct ssh *ssh, Channel *c) 2332 { 2333 channel_handle_rfd(ssh, c); 2334 channel_handle_wfd(ssh, c); 2335 channel_handle_efd(ssh, c); 2336 channel_check_window(ssh, c); 2337 } 2338 2339 static u_int 2340 read_mux(struct ssh *ssh, Channel *c, u_int need) 2341 { 2342 char buf[CHAN_RBUF]; 2343 ssize_t len; 2344 u_int rlen; 2345 int r; 2346 2347 if (sshbuf_len(c->input) < need) { 2348 rlen = need - sshbuf_len(c->input); 2349 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2350 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2351 return sshbuf_len(c->input); 2352 if (len <= 0) { 2353 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2354 c->self, c->rfd, len); 2355 chan_read_failed(ssh, c); 2356 return 0; 2357 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2358 fatal_fr(r, "channel %i: append", c->self); 2359 } 2360 return sshbuf_len(c->input); 2361 } 2362 2363 static void 2364 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2365 { 2366 u_int need; 2367 2368 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2369 return; 2370 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2371 return; 2372 if (c->mux_pause) 2373 return; 2374 2375 /* 2376 * Don't not read past the precise end of packets to 2377 * avoid disrupting fd passing. 2378 */ 2379 if (read_mux(ssh, c, 4) < 4) /* read header */ 2380 return; 2381 /* XXX sshbuf_peek_u32 */ 2382 need = PEEK_U32(sshbuf_ptr(c->input)); 2383 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2384 if (need > CHANNEL_MUX_MAX_PACKET) { 2385 debug2("channel %d: packet too big %u > %u", 2386 c->self, CHANNEL_MUX_MAX_PACKET, need); 2387 chan_rcvd_oclose(ssh, c); 2388 return; 2389 } 2390 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2391 return; 2392 if (c->mux_rcb(ssh, c) != 0) { 2393 debug("channel %d: mux_rcb failed", c->self); 2394 chan_mark_dead(ssh, c); 2395 return; 2396 } 2397 } 2398 2399 static void 2400 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2401 { 2402 ssize_t len; 2403 int r; 2404 2405 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2406 return; 2407 if (sshbuf_len(c->output) == 0) 2408 return; 2409 2410 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2411 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2412 return; 2413 if (len <= 0) { 2414 chan_mark_dead(ssh, c); 2415 return; 2416 } 2417 if ((r = sshbuf_consume(c->output, len)) != 0) 2418 fatal_fr(r, "channel %i: consume", c->self); 2419 } 2420 2421 static void 2422 channel_post_mux_client(struct ssh *ssh, Channel *c) 2423 { 2424 channel_post_mux_client_read(ssh, c); 2425 channel_post_mux_client_write(ssh, c); 2426 } 2427 2428 static void 2429 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2430 { 2431 Channel *nc; 2432 struct sockaddr_storage addr; 2433 socklen_t addrlen; 2434 int newsock; 2435 uid_t euid; 2436 gid_t egid; 2437 2438 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2439 return; 2440 2441 debug("multiplexing control connection"); 2442 2443 /* 2444 * Accept connection on control socket 2445 */ 2446 memset(&addr, 0, sizeof(addr)); 2447 addrlen = sizeof(addr); 2448 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2449 &addrlen)) == -1) { 2450 error_f("accept: %s", strerror(errno)); 2451 if (errno == EMFILE || errno == ENFILE) 2452 c->notbefore = monotime() + 1; 2453 return; 2454 } 2455 2456 if (getpeereid(newsock, &euid, &egid) == -1) { 2457 error_f("getpeereid failed: %s", strerror(errno)); 2458 close(newsock); 2459 return; 2460 } 2461 if ((euid != 0) && (getuid() != euid)) { 2462 error("multiplex uid mismatch: peer euid %u != uid %u", 2463 (u_int)euid, (u_int)getuid()); 2464 close(newsock); 2465 return; 2466 } 2467 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2468 newsock, newsock, -1, c->local_window_max, 2469 c->local_maxpacket, 0, "mux-control", 1); 2470 nc->mux_rcb = c->mux_rcb; 2471 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2472 /* establish state */ 2473 nc->mux_rcb(ssh, nc); 2474 /* mux state transitions must not elicit protocol messages */ 2475 nc->flags |= CHAN_LOCAL; 2476 } 2477 2478 static void 2479 channel_handler_init(struct ssh_channels *sc) 2480 { 2481 chan_fn **pre, **post; 2482 2483 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2484 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2485 fatal_f("allocation failed"); 2486 2487 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2488 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2489 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2490 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2491 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2492 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2493 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2494 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2495 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2496 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2497 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2498 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2499 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2500 2501 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2502 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2503 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2504 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2505 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2506 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2507 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2508 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2509 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2510 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2511 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2512 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2513 2514 sc->channel_pre = pre; 2515 sc->channel_post = post; 2516 } 2517 2518 /* gc dead channels */ 2519 static void 2520 channel_garbage_collect(struct ssh *ssh, Channel *c) 2521 { 2522 if (c == NULL) 2523 return; 2524 if (c->detach_user != NULL) { 2525 if (!chan_is_dead(ssh, c, c->detach_close)) 2526 return; 2527 2528 debug2("channel %d: gc: notify user", c->self); 2529 c->detach_user(ssh, c->self, 0, NULL); 2530 /* if we still have a callback */ 2531 if (c->detach_user != NULL) 2532 return; 2533 debug2("channel %d: gc: user detached", c->self); 2534 } 2535 if (!chan_is_dead(ssh, c, 1)) 2536 return; 2537 debug2("channel %d: garbage collecting", c->self); 2538 channel_free(ssh, c); 2539 } 2540 2541 enum channel_table { CHAN_PRE, CHAN_POST }; 2542 2543 static void 2544 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2545 { 2546 struct ssh_channels *sc = ssh->chanctxt; 2547 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2548 u_int i, oalloc; 2549 Channel *c; 2550 time_t now; 2551 2552 now = monotime(); 2553 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2554 c = sc->channels[i]; 2555 if (c == NULL) 2556 continue; 2557 /* Try to keep IO going while rekeying */ 2558 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2559 continue; 2560 if (c->delayed) { 2561 if (table == CHAN_PRE) 2562 c->delayed = 0; 2563 else 2564 continue; 2565 } 2566 if (ftab[c->type] != NULL) { 2567 if (table == CHAN_PRE && 2568 c->type == SSH_CHANNEL_OPEN && 2569 c->inactive_deadline != 0 && c->lastused != 0 && 2570 now >= c->lastused + c->inactive_deadline) { 2571 /* channel closed for inactivity */ 2572 verbose("channel %d: closing after %u seconds " 2573 "of inactivity", c->self, 2574 c->inactive_deadline); 2575 channel_force_close(ssh, c, 1); 2576 } else if (c->notbefore <= now) { 2577 /* Run handlers that are not paused. */ 2578 (*ftab[c->type])(ssh, c); 2579 /* inactivity timeouts must interrupt poll() */ 2580 if (timeout != NULL && 2581 c->type == SSH_CHANNEL_OPEN && 2582 c->lastused != 0 && 2583 c->inactive_deadline != 0) { 2584 ptimeout_deadline_monotime(timeout, 2585 c->lastused + c->inactive_deadline); 2586 } 2587 } else if (timeout != NULL) { 2588 /* 2589 * Arrange for poll() wakeup when channel pause 2590 * timer expires. 2591 */ 2592 ptimeout_deadline_monotime(timeout, 2593 c->notbefore); 2594 } 2595 } 2596 channel_garbage_collect(ssh, c); 2597 } 2598 } 2599 2600 /* 2601 * Create sockets before preparing IO. 2602 * This is necessary for things that need to happen after reading 2603 * the network-input but need to be completed before IO event setup, e.g. 2604 * because they may create new channels. 2605 */ 2606 static void 2607 channel_before_prepare_io(struct ssh *ssh) 2608 { 2609 struct ssh_channels *sc = ssh->chanctxt; 2610 Channel *c; 2611 u_int i, oalloc; 2612 2613 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2614 c = sc->channels[i]; 2615 if (c == NULL) 2616 continue; 2617 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2618 channel_before_prepare_io_rdynamic(ssh, c); 2619 } 2620 } 2621 2622 static void 2623 dump_channel_poll(const char *func, const char *what, Channel *c, 2624 u_int pollfd_offset, struct pollfd *pfd) 2625 { 2626 #ifdef DEBUG_CHANNEL_POLL 2627 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2628 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2629 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2630 c->rfd, c->wfd, c->efd, c->sock, 2631 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2632 c->io_want, c->io_ready, 2633 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2634 #endif 2635 } 2636 2637 /* Prepare pollfd entries for a single channel */ 2638 static void 2639 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2640 struct pollfd *pfd, u_int npfd) 2641 { 2642 u_int ev, p = *next_pollfd; 2643 2644 if (c == NULL) 2645 return; 2646 if (p + 4 > npfd) { 2647 /* Shouldn't happen */ 2648 fatal_f("channel %d: bad pfd offset %u (max %u)", 2649 c->self, p, npfd); 2650 } 2651 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2652 /* 2653 * prepare c->rfd 2654 * 2655 * This is a special case, since c->rfd might be the same as 2656 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2657 * IO too. 2658 */ 2659 if (c->rfd != -1) { 2660 ev = 0; 2661 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2662 ev |= POLLIN; 2663 /* rfd == wfd */ 2664 if (c->wfd == c->rfd) { 2665 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2666 ev |= POLLOUT; 2667 } 2668 /* rfd == efd */ 2669 if (c->efd == c->rfd) { 2670 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2671 ev |= POLLIN; 2672 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2673 ev |= POLLOUT; 2674 } 2675 /* rfd == sock */ 2676 if (c->sock == c->rfd) { 2677 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2678 ev |= POLLIN; 2679 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2680 ev |= POLLOUT; 2681 } 2682 /* Pack a pfd entry if any event armed for this fd */ 2683 if (ev != 0) { 2684 c->pfds[0] = p; 2685 pfd[p].fd = c->rfd; 2686 pfd[p].events = ev; 2687 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2688 p++; 2689 } 2690 } 2691 /* prepare c->wfd if wanting IO and not already handled above */ 2692 if (c->wfd != -1 && c->rfd != c->wfd) { 2693 ev = 0; 2694 if ((c->io_want & SSH_CHAN_IO_WFD)) 2695 ev |= POLLOUT; 2696 /* Pack a pfd entry if any event armed for this fd */ 2697 if (ev != 0) { 2698 c->pfds[1] = p; 2699 pfd[p].fd = c->wfd; 2700 pfd[p].events = ev; 2701 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2702 p++; 2703 } 2704 } 2705 /* prepare c->efd if wanting IO and not already handled above */ 2706 if (c->efd != -1 && c->rfd != c->efd) { 2707 ev = 0; 2708 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2709 ev |= POLLIN; 2710 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2711 ev |= POLLOUT; 2712 /* Pack a pfd entry if any event armed for this fd */ 2713 if (ev != 0) { 2714 c->pfds[2] = p; 2715 pfd[p].fd = c->efd; 2716 pfd[p].events = ev; 2717 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2718 p++; 2719 } 2720 } 2721 /* prepare c->sock if wanting IO and not already handled above */ 2722 if (c->sock != -1 && c->rfd != c->sock) { 2723 ev = 0; 2724 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2725 ev |= POLLIN; 2726 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2727 ev |= POLLOUT; 2728 /* Pack a pfd entry if any event armed for this fd */ 2729 if (ev != 0) { 2730 c->pfds[3] = p; 2731 pfd[p].fd = c->sock; 2732 pfd[p].events = 0; 2733 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2734 p++; 2735 } 2736 } 2737 *next_pollfd = p; 2738 } 2739 2740 /* * Allocate/prepare poll structure */ 2741 void 2742 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2743 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2744 { 2745 struct ssh_channels *sc = ssh->chanctxt; 2746 u_int i, oalloc, p, npfd = npfd_reserved; 2747 2748 channel_before_prepare_io(ssh); /* might create a new channel */ 2749 /* clear out I/O flags from last poll */ 2750 for (i = 0; i < sc->channels_alloc; i++) { 2751 if (sc->channels[i] == NULL) 2752 continue; 2753 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2754 } 2755 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2756 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2757 fatal_f("too many channels"); /* shouldn't happen */ 2758 npfd += sc->channels_alloc * 4; 2759 if (npfd > *npfd_allocp) { 2760 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2761 npfd, sizeof(**pfdp)); 2762 *npfd_allocp = npfd; 2763 } 2764 *npfd_activep = npfd_reserved; 2765 oalloc = sc->channels_alloc; 2766 2767 channel_handler(ssh, CHAN_PRE, timeout); 2768 2769 if (oalloc != sc->channels_alloc) { 2770 /* shouldn't happen */ 2771 fatal_f("channels_alloc changed during CHAN_PRE " 2772 "(was %u, now %u)", oalloc, sc->channels_alloc); 2773 } 2774 2775 /* Prepare pollfd */ 2776 p = npfd_reserved; 2777 for (i = 0; i < sc->channels_alloc; i++) 2778 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2779 *npfd_activep = p; 2780 } 2781 2782 static void 2783 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2784 const char *what, u_int revents_mask, u_int ready) 2785 { 2786 struct pollfd *pfd = &pfds[p]; 2787 2788 if (fd == -1) 2789 return; 2790 if (p == -1 || (u_int)p >= npfd) 2791 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2792 dump_channel_poll(__func__, what, c, p, pfd); 2793 if (pfd->fd != fd) { 2794 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2795 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2796 c->rfd, c->wfd, c->efd, c->sock); 2797 } 2798 if ((pfd->revents & POLLNVAL) != 0) { 2799 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2800 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2801 } 2802 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2803 c->io_ready |= ready & c->io_want; 2804 } 2805 2806 /* 2807 * After poll, perform any appropriate operations for channels which have 2808 * events pending. 2809 */ 2810 void 2811 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2812 { 2813 struct ssh_channels *sc = ssh->chanctxt; 2814 u_int i; 2815 int p; 2816 Channel *c; 2817 2818 #ifdef DEBUG_CHANNEL_POLL 2819 for (p = 0; p < (int)npfd; p++) { 2820 if (pfd[p].revents == 0) 2821 continue; 2822 debug_f("pfd[%u].fd %d rev 0x%04x", 2823 p, pfd[p].fd, pfd[p].revents); 2824 } 2825 #endif 2826 2827 /* Convert pollfd into c->io_ready */ 2828 for (i = 0; i < sc->channels_alloc; i++) { 2829 c = sc->channels[i]; 2830 if (c == NULL) 2831 continue; 2832 /* if rfd is shared with efd/sock then wfd should be too */ 2833 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2834 (c->rfd == c->efd || c->rfd == c->sock)) { 2835 /* Shouldn't happen */ 2836 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2837 c->self, c->rfd, c->wfd, c->efd, c->sock); 2838 } 2839 c->io_ready = 0; 2840 /* rfd, potentially shared with wfd, efd and sock */ 2841 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2842 fd_ready(c, p, pfd, npfd, c->rfd, 2843 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2844 if (c->rfd == c->wfd) { 2845 fd_ready(c, p, pfd, npfd, c->wfd, 2846 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2847 } 2848 if (c->rfd == c->efd) { 2849 fd_ready(c, p, pfd, npfd, c->efd, 2850 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2851 fd_ready(c, p, pfd, npfd, c->efd, 2852 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2853 } 2854 if (c->rfd == c->sock) { 2855 fd_ready(c, p, pfd, npfd, c->sock, 2856 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2857 fd_ready(c, p, pfd, npfd, c->sock, 2858 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2859 } 2860 dump_channel_poll(__func__, "rfd", c, p, pfd); 2861 } 2862 /* wfd */ 2863 if (c->wfd != -1 && c->wfd != c->rfd && 2864 (p = c->pfds[1]) != -1) { 2865 fd_ready(c, p, pfd, npfd, c->wfd, 2866 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2867 dump_channel_poll(__func__, "wfd", c, p, pfd); 2868 } 2869 /* efd */ 2870 if (c->efd != -1 && c->efd != c->rfd && 2871 (p = c->pfds[2]) != -1) { 2872 fd_ready(c, p, pfd, npfd, c->efd, 2873 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2874 fd_ready(c, p, pfd, npfd, c->efd, 2875 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2876 dump_channel_poll(__func__, "efd", c, p, pfd); 2877 } 2878 /* sock */ 2879 if (c->sock != -1 && c->sock != c->rfd && 2880 (p = c->pfds[3]) != -1) { 2881 fd_ready(c, p, pfd, npfd, c->sock, 2882 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2883 fd_ready(c, p, pfd, npfd, c->sock, 2884 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2885 dump_channel_poll(__func__, "sock", c, p, pfd); 2886 } 2887 } 2888 channel_handler(ssh, CHAN_POST, NULL); 2889 } 2890 2891 /* 2892 * Enqueue data for channels with open or draining c->input. 2893 */ 2894 static void 2895 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2896 { 2897 size_t len, plen; 2898 const u_char *pkt; 2899 int r; 2900 2901 if ((len = sshbuf_len(c->input)) == 0) { 2902 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2903 /* 2904 * input-buffer is empty and read-socket shutdown: 2905 * tell peer, that we will not send more data: 2906 * send IEOF. 2907 * hack for extended data: delay EOF if EFD still 2908 * in use. 2909 */ 2910 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2911 debug2("channel %d: " 2912 "ibuf_empty delayed efd %d/(%zu)", 2913 c->self, c->efd, sshbuf_len(c->extended)); 2914 else 2915 chan_ibuf_empty(ssh, c); 2916 } 2917 return; 2918 } 2919 2920 if (!c->have_remote_id) 2921 fatal_f("channel %d: no remote id", c->self); 2922 2923 if (c->datagram) { 2924 /* Check datagram will fit; drop if not */ 2925 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2926 fatal_fr(r, "channel %i: get datagram", c->self); 2927 /* 2928 * XXX this does tail-drop on the datagram queue which is 2929 * usually suboptimal compared to head-drop. Better to have 2930 * backpressure at read time? (i.e. read + discard) 2931 */ 2932 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2933 debug("channel %d: datagram too big", c->self); 2934 return; 2935 } 2936 /* Enqueue it */ 2937 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2938 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2939 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2940 (r = sshpkt_send(ssh)) != 0) 2941 fatal_fr(r, "channel %i: send datagram", c->self); 2942 c->remote_window -= plen; 2943 return; 2944 } 2945 2946 /* Enqueue packet for buffered data. */ 2947 if (len > c->remote_window) 2948 len = c->remote_window; 2949 if (len > c->remote_maxpacket) 2950 len = c->remote_maxpacket; 2951 if (len == 0) 2952 return; 2953 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2954 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2955 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2956 (r = sshpkt_send(ssh)) != 0) 2957 fatal_fr(r, "channel %i: send data", c->self); 2958 if ((r = sshbuf_consume(c->input, len)) != 0) 2959 fatal_fr(r, "channel %i: consume", c->self); 2960 c->remote_window -= len; 2961 } 2962 2963 /* 2964 * Enqueue data for channels with open c->extended in read mode. 2965 */ 2966 static void 2967 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2968 { 2969 size_t len; 2970 int r; 2971 2972 if ((len = sshbuf_len(c->extended)) == 0) 2973 return; 2974 2975 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2976 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2977 if (len > c->remote_window) 2978 len = c->remote_window; 2979 if (len > c->remote_maxpacket) 2980 len = c->remote_maxpacket; 2981 if (len == 0) 2982 return; 2983 if (!c->have_remote_id) 2984 fatal_f("channel %d: no remote id", c->self); 2985 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2986 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2987 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2988 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2989 (r = sshpkt_send(ssh)) != 0) 2990 fatal_fr(r, "channel %i: data", c->self); 2991 if ((r = sshbuf_consume(c->extended, len)) != 0) 2992 fatal_fr(r, "channel %i: consume", c->self); 2993 c->remote_window -= len; 2994 debug2("channel %d: sent ext data %zu", c->self, len); 2995 } 2996 2997 /* If there is data to send to the connection, enqueue some of it now. */ 2998 void 2999 channel_output_poll(struct ssh *ssh) 3000 { 3001 struct ssh_channels *sc = ssh->chanctxt; 3002 Channel *c; 3003 u_int i; 3004 3005 for (i = 0; i < sc->channels_alloc; i++) { 3006 c = sc->channels[i]; 3007 if (c == NULL) 3008 continue; 3009 3010 /* 3011 * We are only interested in channels that can have buffered 3012 * incoming data. 3013 */ 3014 if (c->type != SSH_CHANNEL_OPEN) 3015 continue; 3016 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3017 /* XXX is this true? */ 3018 debug3("channel %d: will not send data after close", 3019 c->self); 3020 continue; 3021 } 3022 3023 /* Get the amount of buffered data for this channel. */ 3024 if (c->istate == CHAN_INPUT_OPEN || 3025 c->istate == CHAN_INPUT_WAIT_DRAIN) 3026 channel_output_poll_input_open(ssh, c); 3027 /* Send extended data, i.e. stderr */ 3028 if (!(c->flags & CHAN_EOF_SENT) && 3029 c->extended_usage == CHAN_EXTENDED_READ) 3030 channel_output_poll_extended_read(ssh, c); 3031 } 3032 } 3033 3034 /* -- mux proxy support */ 3035 3036 /* 3037 * When multiplexing channel messages for mux clients we have to deal 3038 * with downstream messages from the mux client and upstream messages 3039 * from the ssh server: 3040 * 1) Handling downstream messages is straightforward and happens 3041 * in channel_proxy_downstream(): 3042 * - We forward all messages (mostly) unmodified to the server. 3043 * - However, in order to route messages from upstream to the correct 3044 * downstream client, we have to replace the channel IDs used by the 3045 * mux clients with a unique channel ID because the mux clients might 3046 * use conflicting channel IDs. 3047 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3048 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3049 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3050 * with the newly allocated channel ID. 3051 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3052 * channels and processed by channel_proxy_upstream(). The local channel ID 3053 * is then translated back to the original mux client ID. 3054 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3055 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3056 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3057 * downstream mux client are removed. 3058 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3059 * requires more work, because they are not addressed to a specific 3060 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3061 * out whether the request is addressed to the local client or a 3062 * specific downstream client based on the listen-address/port. 3063 * 6) Agent and X11-Forwarding have a similar problem and are currently 3064 * not supported as the matching session/channel cannot be identified 3065 * easily. 3066 */ 3067 3068 /* 3069 * receive packets from downstream mux clients: 3070 * channel callback fired on read from mux client, creates 3071 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3072 * on channel creation. 3073 */ 3074 int 3075 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3076 { 3077 Channel *c = NULL; 3078 struct sshbuf *original = NULL, *modified = NULL; 3079 const u_char *cp; 3080 char *ctype = NULL, *listen_host = NULL; 3081 u_char type; 3082 size_t have; 3083 int ret = -1, r; 3084 u_int id, remote_id, listen_port; 3085 3086 /* sshbuf_dump(downstream->input, stderr); */ 3087 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3088 != 0) { 3089 error_fr(r, "parse"); 3090 return -1; 3091 } 3092 if (have < 2) { 3093 error_f("short message"); 3094 return -1; 3095 } 3096 type = cp[1]; 3097 /* skip padlen + type */ 3098 cp += 2; 3099 have -= 2; 3100 if (ssh_packet_log_type(type)) 3101 debug3_f("channel %u: down->up: type %u", 3102 downstream->self, type); 3103 3104 switch (type) { 3105 case SSH2_MSG_CHANNEL_OPEN: 3106 if ((original = sshbuf_from(cp, have)) == NULL || 3107 (modified = sshbuf_new()) == NULL) { 3108 error_f("alloc"); 3109 goto out; 3110 } 3111 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3112 (r = sshbuf_get_u32(original, &id)) != 0) { 3113 error_fr(r, "parse"); 3114 goto out; 3115 } 3116 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3117 -1, -1, -1, 0, 0, 0, ctype, 1); 3118 c->mux_ctx = downstream; /* point to mux client */ 3119 c->mux_downstream_id = id; /* original downstream id */ 3120 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3121 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3122 (r = sshbuf_putb(modified, original)) != 0) { 3123 error_fr(r, "compose"); 3124 channel_free(ssh, c); 3125 goto out; 3126 } 3127 break; 3128 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3129 /* 3130 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3131 * need to parse 'remote_id' instead of 'ctype'. 3132 */ 3133 if ((original = sshbuf_from(cp, have)) == NULL || 3134 (modified = sshbuf_new()) == NULL) { 3135 error_f("alloc"); 3136 goto out; 3137 } 3138 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3139 (r = sshbuf_get_u32(original, &id)) != 0) { 3140 error_fr(r, "parse"); 3141 goto out; 3142 } 3143 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3144 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3145 c->mux_ctx = downstream; /* point to mux client */ 3146 c->mux_downstream_id = id; 3147 c->remote_id = remote_id; 3148 c->have_remote_id = 1; 3149 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3150 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3151 (r = sshbuf_putb(modified, original)) != 0) { 3152 error_fr(r, "compose"); 3153 channel_free(ssh, c); 3154 goto out; 3155 } 3156 break; 3157 case SSH2_MSG_GLOBAL_REQUEST: 3158 if ((original = sshbuf_from(cp, have)) == NULL) { 3159 error_f("alloc"); 3160 goto out; 3161 } 3162 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3163 error_fr(r, "parse"); 3164 goto out; 3165 } 3166 if (strcmp(ctype, "tcpip-forward") != 0) { 3167 error_f("unsupported request %s", ctype); 3168 goto out; 3169 } 3170 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3171 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3172 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3173 error_fr(r, "parse"); 3174 goto out; 3175 } 3176 if (listen_port > 65535) { 3177 error_f("tcpip-forward for %s: bad port %u", 3178 listen_host, listen_port); 3179 goto out; 3180 } 3181 /* Record that connection to this host/port is permitted. */ 3182 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 3183 listen_host, NULL, (int)listen_port, downstream); 3184 listen_host = NULL; 3185 break; 3186 case SSH2_MSG_CHANNEL_CLOSE: 3187 if (have < 4) 3188 break; 3189 remote_id = PEEK_U32(cp); 3190 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3191 if (c->flags & CHAN_CLOSE_RCVD) 3192 channel_free(ssh, c); 3193 else 3194 c->flags |= CHAN_CLOSE_SENT; 3195 } 3196 break; 3197 } 3198 if (modified) { 3199 if ((r = sshpkt_start(ssh, type)) != 0 || 3200 (r = sshpkt_putb(ssh, modified)) != 0 || 3201 (r = sshpkt_send(ssh)) != 0) { 3202 error_fr(r, "send"); 3203 goto out; 3204 } 3205 } else { 3206 if ((r = sshpkt_start(ssh, type)) != 0 || 3207 (r = sshpkt_put(ssh, cp, have)) != 0 || 3208 (r = sshpkt_send(ssh)) != 0) { 3209 error_fr(r, "send"); 3210 goto out; 3211 } 3212 } 3213 ret = 0; 3214 out: 3215 free(ctype); 3216 free(listen_host); 3217 sshbuf_free(original); 3218 sshbuf_free(modified); 3219 return ret; 3220 } 3221 3222 /* 3223 * receive packets from upstream server and de-multiplex packets 3224 * to correct downstream: 3225 * implemented as a helper for channel input handlers, 3226 * replaces local (proxy) channel ID with downstream channel ID. 3227 */ 3228 int 3229 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3230 { 3231 struct sshbuf *b = NULL; 3232 Channel *downstream; 3233 const u_char *cp = NULL; 3234 size_t len; 3235 int r; 3236 3237 /* 3238 * When receiving packets from the peer we need to check whether we 3239 * need to forward the packets to the mux client. In this case we 3240 * restore the original channel id and keep track of CLOSE messages, 3241 * so we can cleanup the channel. 3242 */ 3243 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3244 return 0; 3245 if ((downstream = c->mux_ctx) == NULL) 3246 return 0; 3247 switch (type) { 3248 case SSH2_MSG_CHANNEL_CLOSE: 3249 case SSH2_MSG_CHANNEL_DATA: 3250 case SSH2_MSG_CHANNEL_EOF: 3251 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3252 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3253 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3254 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3255 case SSH2_MSG_CHANNEL_SUCCESS: 3256 case SSH2_MSG_CHANNEL_FAILURE: 3257 case SSH2_MSG_CHANNEL_REQUEST: 3258 break; 3259 default: 3260 debug2_f("channel %u: unsupported type %u", c->self, type); 3261 return 0; 3262 } 3263 if ((b = sshbuf_new()) == NULL) { 3264 error_f("alloc reply"); 3265 goto out; 3266 } 3267 /* get remaining payload (after id) */ 3268 cp = sshpkt_ptr(ssh, &len); 3269 if (cp == NULL) { 3270 error_f("no packet"); 3271 goto out; 3272 } 3273 /* translate id and send to muxclient */ 3274 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3275 (r = sshbuf_put_u8(b, type)) != 0 || 3276 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3277 (r = sshbuf_put(b, cp, len)) != 0 || 3278 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3279 error_fr(r, "compose muxclient"); 3280 goto out; 3281 } 3282 /* sshbuf_dump(b, stderr); */ 3283 if (ssh_packet_log_type(type)) 3284 debug3_f("channel %u: up->down: type %u", c->self, type); 3285 out: 3286 /* update state */ 3287 switch (type) { 3288 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3289 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3290 if (cp && len > 4) { 3291 c->remote_id = PEEK_U32(cp); 3292 c->have_remote_id = 1; 3293 } 3294 break; 3295 case SSH2_MSG_CHANNEL_CLOSE: 3296 if (c->flags & CHAN_CLOSE_SENT) 3297 channel_free(ssh, c); 3298 else 3299 c->flags |= CHAN_CLOSE_RCVD; 3300 break; 3301 } 3302 sshbuf_free(b); 3303 return 1; 3304 } 3305 3306 /* -- protocol input */ 3307 3308 /* Parse a channel ID from the current packet */ 3309 static int 3310 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3311 { 3312 u_int32_t id; 3313 int r; 3314 3315 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3316 error_r(r, "%s: parse id", where); 3317 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3318 } 3319 if (id > INT_MAX) { 3320 error_r(r, "%s: bad channel id %u", where, id); 3321 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3322 } 3323 return (int)id; 3324 } 3325 3326 /* Lookup a channel from an ID in the current packet */ 3327 static Channel * 3328 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3329 { 3330 int id = channel_parse_id(ssh, where, what); 3331 Channel *c; 3332 3333 if ((c = channel_lookup(ssh, id)) == NULL) { 3334 ssh_packet_disconnect(ssh, 3335 "%s packet referred to nonexistent channel %d", what, id); 3336 } 3337 return c; 3338 } 3339 3340 int 3341 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3342 { 3343 const u_char *data; 3344 size_t data_len, win_len; 3345 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3346 int r; 3347 3348 if (channel_proxy_upstream(c, type, seq, ssh)) 3349 return 0; 3350 3351 /* Ignore any data for non-open channels (might happen on close) */ 3352 if (c->type != SSH_CHANNEL_OPEN && 3353 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3354 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3355 c->type != SSH_CHANNEL_X11_OPEN) 3356 return 0; 3357 3358 /* Get the data. */ 3359 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3360 (r = sshpkt_get_end(ssh)) != 0) 3361 fatal_fr(r, "channel %i: get data", c->self); 3362 3363 win_len = data_len; 3364 if (c->datagram) 3365 win_len += 4; /* string length header */ 3366 3367 /* 3368 * The sending side reduces its window as it sends data, so we 3369 * must 'fake' consumption of the data in order to ensure that window 3370 * updates are sent back. Otherwise the connection might deadlock. 3371 */ 3372 if (c->ostate != CHAN_OUTPUT_OPEN) { 3373 c->local_window -= win_len; 3374 c->local_consumed += win_len; 3375 return 0; 3376 } 3377 3378 if (win_len > c->local_maxpacket) { 3379 logit("channel %d: rcvd big packet %zu, maxpack %u", 3380 c->self, win_len, c->local_maxpacket); 3381 return 0; 3382 } 3383 if (win_len > c->local_window) { 3384 logit("channel %d: rcvd too much data %zu, win %u", 3385 c->self, win_len, c->local_window); 3386 return 0; 3387 } 3388 c->local_window -= win_len; 3389 3390 if (c->datagram) { 3391 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3392 fatal_fr(r, "channel %i: append datagram", c->self); 3393 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3394 fatal_fr(r, "channel %i: append data", c->self); 3395 3396 return 0; 3397 } 3398 3399 int 3400 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3401 { 3402 const u_char *data; 3403 size_t data_len; 3404 u_int32_t tcode; 3405 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3406 int r; 3407 3408 if (channel_proxy_upstream(c, type, seq, ssh)) 3409 return 0; 3410 if (c->type != SSH_CHANNEL_OPEN) { 3411 logit("channel %d: ext data for non open", c->self); 3412 return 0; 3413 } 3414 if (c->flags & CHAN_EOF_RCVD) { 3415 if (ssh->compat & SSH_BUG_EXTEOF) 3416 debug("channel %d: accepting ext data after eof", 3417 c->self); 3418 else 3419 ssh_packet_disconnect(ssh, "Received extended_data " 3420 "after EOF on channel %d.", c->self); 3421 } 3422 3423 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3424 error_fr(r, "parse tcode"); 3425 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3426 } 3427 if (c->efd == -1 || 3428 c->extended_usage != CHAN_EXTENDED_WRITE || 3429 tcode != SSH2_EXTENDED_DATA_STDERR) { 3430 logit("channel %d: bad ext data", c->self); 3431 return 0; 3432 } 3433 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3434 (r = sshpkt_get_end(ssh)) != 0) { 3435 error_fr(r, "parse data"); 3436 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3437 } 3438 3439 if (data_len > c->local_window) { 3440 logit("channel %d: rcvd too much extended_data %zu, win %u", 3441 c->self, data_len, c->local_window); 3442 return 0; 3443 } 3444 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3445 /* XXX sshpkt_getb? */ 3446 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3447 error_fr(r, "append"); 3448 c->local_window -= data_len; 3449 return 0; 3450 } 3451 3452 int 3453 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3454 { 3455 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3456 int r; 3457 3458 if ((r = sshpkt_get_end(ssh)) != 0) { 3459 error_fr(r, "parse data"); 3460 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3461 } 3462 3463 if (channel_proxy_upstream(c, type, seq, ssh)) 3464 return 0; 3465 chan_rcvd_ieof(ssh, c); 3466 3467 /* XXX force input close */ 3468 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3469 debug("channel %d: FORCE input drain", c->self); 3470 c->istate = CHAN_INPUT_WAIT_DRAIN; 3471 if (sshbuf_len(c->input) == 0) 3472 chan_ibuf_empty(ssh, c); 3473 } 3474 return 0; 3475 } 3476 3477 int 3478 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3479 { 3480 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3481 int r; 3482 3483 if (channel_proxy_upstream(c, type, seq, ssh)) 3484 return 0; 3485 if ((r = sshpkt_get_end(ssh)) != 0) { 3486 error_fr(r, "parse data"); 3487 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3488 } 3489 chan_rcvd_oclose(ssh, c); 3490 return 0; 3491 } 3492 3493 int 3494 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3495 { 3496 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3497 u_int32_t remote_window, remote_maxpacket; 3498 int r; 3499 3500 if (channel_proxy_upstream(c, type, seq, ssh)) 3501 return 0; 3502 if (c->type != SSH_CHANNEL_OPENING) 3503 ssh_packet_disconnect(ssh, "Received open confirmation for " 3504 "non-opening channel %d.", c->self); 3505 /* 3506 * Record the remote channel number and mark that the channel 3507 * is now open. 3508 */ 3509 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3510 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3511 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3512 (r = sshpkt_get_end(ssh)) != 0) { 3513 error_fr(r, "window/maxpacket"); 3514 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3515 } 3516 3517 c->have_remote_id = 1; 3518 c->remote_window = remote_window; 3519 c->remote_maxpacket = remote_maxpacket; 3520 c->type = SSH_CHANNEL_OPEN; 3521 if (c->open_confirm) { 3522 debug2_f("channel %d: callback start", c->self); 3523 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3524 debug2_f("channel %d: callback done", c->self); 3525 } 3526 c->lastused = monotime(); 3527 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3528 c->remote_window, c->remote_maxpacket); 3529 return 0; 3530 } 3531 3532 static const char * 3533 reason2txt(int reason) 3534 { 3535 switch (reason) { 3536 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3537 return "administratively prohibited"; 3538 case SSH2_OPEN_CONNECT_FAILED: 3539 return "connect failed"; 3540 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3541 return "unknown channel type"; 3542 case SSH2_OPEN_RESOURCE_SHORTAGE: 3543 return "resource shortage"; 3544 } 3545 return "unknown reason"; 3546 } 3547 3548 int 3549 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3550 { 3551 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3552 u_int32_t reason; 3553 char *msg = NULL; 3554 int r; 3555 3556 if (channel_proxy_upstream(c, type, seq, ssh)) 3557 return 0; 3558 if (c->type != SSH_CHANNEL_OPENING) 3559 ssh_packet_disconnect(ssh, "Received open failure for " 3560 "non-opening channel %d.", c->self); 3561 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3562 error_fr(r, "parse reason"); 3563 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3564 } 3565 /* skip language */ 3566 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3567 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3568 (r = sshpkt_get_end(ssh)) != 0) { 3569 error_fr(r, "parse msg/lang"); 3570 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3571 } 3572 logit("channel %d: open failed: %s%s%s", c->self, 3573 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3574 free(msg); 3575 if (c->open_confirm) { 3576 debug2_f("channel %d: callback start", c->self); 3577 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3578 debug2_f("channel %d: callback done", c->self); 3579 } 3580 /* Schedule the channel for cleanup/deletion. */ 3581 chan_mark_dead(ssh, c); 3582 return 0; 3583 } 3584 3585 int 3586 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3587 { 3588 int id = channel_parse_id(ssh, __func__, "window adjust"); 3589 Channel *c; 3590 u_int32_t adjust; 3591 u_int new_rwin; 3592 int r; 3593 3594 if ((c = channel_lookup(ssh, id)) == NULL) { 3595 logit("Received window adjust for non-open channel %d.", id); 3596 return 0; 3597 } 3598 3599 if (channel_proxy_upstream(c, type, seq, ssh)) 3600 return 0; 3601 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3602 (r = sshpkt_get_end(ssh)) != 0) { 3603 error_fr(r, "parse adjust"); 3604 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3605 } 3606 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3607 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3608 fatal("channel %d: adjust %u overflows remote window %u", 3609 c->self, adjust, c->remote_window); 3610 } 3611 c->remote_window = new_rwin; 3612 return 0; 3613 } 3614 3615 int 3616 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3617 { 3618 int id = channel_parse_id(ssh, __func__, "status confirm"); 3619 Channel *c; 3620 struct channel_confirm *cc; 3621 3622 /* Reset keepalive timeout */ 3623 ssh_packet_set_alive_timeouts(ssh, 0); 3624 3625 debug2_f("type %d id %d", type, id); 3626 3627 if ((c = channel_lookup(ssh, id)) == NULL) { 3628 logit_f("%d: unknown", id); 3629 return 0; 3630 } 3631 if (channel_proxy_upstream(c, type, seq, ssh)) 3632 return 0; 3633 if (sshpkt_get_end(ssh) != 0) 3634 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3635 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3636 return 0; 3637 cc->cb(ssh, type, c, cc->ctx); 3638 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3639 freezero(cc, sizeof(*cc)); 3640 return 0; 3641 } 3642 3643 /* -- tcp forwarding */ 3644 3645 void 3646 channel_set_af(struct ssh *ssh, int af) 3647 { 3648 ssh->chanctxt->IPv4or6 = af; 3649 } 3650 3651 void 3652 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size) 3653 { 3654 hpn_disabled = external_hpn_disabled; 3655 hpn_buffer_size = external_hpn_buffer_size; 3656 debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size); 3657 } 3658 3659 /* 3660 * Determine whether or not a port forward listens to loopback, the 3661 * specified address or wildcard. On the client, a specified bind 3662 * address will always override gateway_ports. On the server, a 3663 * gateway_ports of 1 (``yes'') will override the client's specification 3664 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3665 * will bind to whatever address the client asked for. 3666 * 3667 * Special-case listen_addrs are: 3668 * 3669 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3670 * "" (empty string), "*" -> wildcard v4/v6 3671 * "localhost" -> loopback v4/v6 3672 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3673 */ 3674 static const char * 3675 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3676 int is_client, struct ForwardOptions *fwd_opts) 3677 { 3678 const char *addr = NULL; 3679 int wildcard = 0; 3680 3681 if (listen_addr == NULL) { 3682 /* No address specified: default to gateway_ports setting */ 3683 if (fwd_opts->gateway_ports) 3684 wildcard = 1; 3685 } else if (fwd_opts->gateway_ports || is_client) { 3686 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3687 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3688 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3689 (!is_client && fwd_opts->gateway_ports == 1)) { 3690 wildcard = 1; 3691 /* 3692 * Notify client if they requested a specific listen 3693 * address and it was overridden. 3694 */ 3695 if (*listen_addr != '\0' && 3696 strcmp(listen_addr, "0.0.0.0") != 0 && 3697 strcmp(listen_addr, "*") != 0) { 3698 ssh_packet_send_debug(ssh, 3699 "Forwarding listen address " 3700 "\"%s\" overridden by server " 3701 "GatewayPorts", listen_addr); 3702 } 3703 } else if (strcmp(listen_addr, "localhost") != 0 || 3704 strcmp(listen_addr, "127.0.0.1") == 0 || 3705 strcmp(listen_addr, "::1") == 0) { 3706 /* 3707 * Accept explicit localhost address when 3708 * GatewayPorts=yes. The "localhost" hostname is 3709 * deliberately skipped here so it will listen on all 3710 * available local address families. 3711 */ 3712 addr = listen_addr; 3713 } 3714 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3715 strcmp(listen_addr, "::1") == 0) { 3716 /* 3717 * If a specific IPv4/IPv6 localhost address has been 3718 * requested then accept it even if gateway_ports is in 3719 * effect. This allows the client to prefer IPv4 or IPv6. 3720 */ 3721 addr = listen_addr; 3722 } 3723 if (wildcardp != NULL) 3724 *wildcardp = wildcard; 3725 return addr; 3726 } 3727 3728 static int 3729 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3730 struct Forward *fwd, int *allocated_listen_port, 3731 struct ForwardOptions *fwd_opts) 3732 { 3733 Channel *c; 3734 int sock, r, success = 0, wildcard = 0, is_client; 3735 struct addrinfo hints, *ai, *aitop; 3736 const char *host, *addr; 3737 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3738 in_port_t *lport_p; 3739 3740 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3741 3742 if (is_client && fwd->connect_path != NULL) { 3743 host = fwd->connect_path; 3744 } else { 3745 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3746 fwd->listen_host : fwd->connect_host; 3747 if (host == NULL) { 3748 error("No forward host name."); 3749 return 0; 3750 } 3751 if (strlen(host) >= NI_MAXHOST) { 3752 error("Forward host name too long."); 3753 return 0; 3754 } 3755 } 3756 3757 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3758 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3759 is_client, fwd_opts); 3760 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3761 (addr == NULL) ? "NULL" : addr); 3762 3763 /* 3764 * getaddrinfo returns a loopback address if the hostname is 3765 * set to NULL and hints.ai_flags is not AI_PASSIVE 3766 */ 3767 memset(&hints, 0, sizeof(hints)); 3768 hints.ai_family = ssh->chanctxt->IPv4or6; 3769 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3770 hints.ai_socktype = SOCK_STREAM; 3771 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3772 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3773 if (addr == NULL) { 3774 /* This really shouldn't happen */ 3775 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3776 ssh_gai_strerror(r)); 3777 } else { 3778 error_f("getaddrinfo(%.64s): %s", addr, 3779 ssh_gai_strerror(r)); 3780 } 3781 return 0; 3782 } 3783 if (allocated_listen_port != NULL) 3784 *allocated_listen_port = 0; 3785 for (ai = aitop; ai; ai = ai->ai_next) { 3786 switch (ai->ai_family) { 3787 case AF_INET: 3788 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3789 sin_port; 3790 break; 3791 case AF_INET6: 3792 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3793 sin6_port; 3794 break; 3795 default: 3796 continue; 3797 } 3798 /* 3799 * If allocating a port for -R forwards, then use the 3800 * same port for all address families. 3801 */ 3802 if (type == SSH_CHANNEL_RPORT_LISTENER && 3803 fwd->listen_port == 0 && allocated_listen_port != NULL && 3804 *allocated_listen_port > 0) 3805 *lport_p = htons(*allocated_listen_port); 3806 3807 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3808 strport, sizeof(strport), 3809 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3810 error_f("getnameinfo failed"); 3811 continue; 3812 } 3813 /* Create a port to listen for the host. */ 3814 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3815 if (sock == -1) { 3816 /* this is no error since kernel may not support ipv6 */ 3817 verbose("socket [%s]:%s: %.100s", ntop, strport, 3818 strerror(errno)); 3819 continue; 3820 } 3821 3822 set_reuseaddr(sock); 3823 3824 debug("Local forwarding listening on %s port %s.", 3825 ntop, strport); 3826 3827 /* Bind the socket to the address. */ 3828 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3829 /* 3830 * address can be in if use ipv6 address is 3831 * already bound 3832 */ 3833 verbose("bind [%s]:%s: %.100s", 3834 ntop, strport, strerror(errno)); 3835 close(sock); 3836 continue; 3837 } 3838 /* Start listening for connections on the socket. */ 3839 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3840 error("listen [%s]:%s: %.100s", ntop, strport, 3841 strerror(errno)); 3842 close(sock); 3843 continue; 3844 } 3845 3846 /* 3847 * fwd->listen_port == 0 requests a dynamically allocated port - 3848 * record what we got. 3849 */ 3850 if (type == SSH_CHANNEL_RPORT_LISTENER && 3851 fwd->listen_port == 0 && 3852 allocated_listen_port != NULL && 3853 *allocated_listen_port == 0) { 3854 *allocated_listen_port = get_local_port(sock); 3855 debug("Allocated listen port %d", 3856 *allocated_listen_port); 3857 } 3858 3859 /* Allocate a channel number for the socket. */ 3860 /* explicitly test for hpn disabled option. if true use smaller window size */ 3861 if (hpn_disabled) 3862 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3863 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3864 0, "port listener", 1); 3865 else 3866 c = channel_new(ssh, "port listener", type, sock, sock, 3867 -1, hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 3868 0, "port listener", 1); 3869 c->path = xstrdup(host); 3870 c->host_port = fwd->connect_port; 3871 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3872 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3873 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3874 c->listening_port = *allocated_listen_port; 3875 else 3876 c->listening_port = fwd->listen_port; 3877 success = 1; 3878 } 3879 if (success == 0) 3880 error_f("cannot listen to port: %d", fwd->listen_port); 3881 freeaddrinfo(aitop); 3882 return success; 3883 } 3884 3885 static int 3886 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3887 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3888 { 3889 struct sockaddr_un sunaddr; 3890 const char *path; 3891 Channel *c; 3892 int port, sock; 3893 mode_t omask; 3894 3895 switch (type) { 3896 case SSH_CHANNEL_UNIX_LISTENER: 3897 if (fwd->connect_path != NULL) { 3898 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3899 error("Local connecting path too long: %s", 3900 fwd->connect_path); 3901 return 0; 3902 } 3903 path = fwd->connect_path; 3904 port = PORT_STREAMLOCAL; 3905 } else { 3906 if (fwd->connect_host == NULL) { 3907 error("No forward host name."); 3908 return 0; 3909 } 3910 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3911 error("Forward host name too long."); 3912 return 0; 3913 } 3914 path = fwd->connect_host; 3915 port = fwd->connect_port; 3916 } 3917 break; 3918 case SSH_CHANNEL_RUNIX_LISTENER: 3919 path = fwd->listen_path; 3920 port = PORT_STREAMLOCAL; 3921 break; 3922 default: 3923 error_f("unexpected channel type %d", type); 3924 return 0; 3925 } 3926 3927 if (fwd->listen_path == NULL) { 3928 error("No forward path name."); 3929 return 0; 3930 } 3931 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3932 error("Local listening path too long: %s", fwd->listen_path); 3933 return 0; 3934 } 3935 3936 debug3_f("type %d path %s", type, fwd->listen_path); 3937 3938 /* Start a Unix domain listener. */ 3939 omask = umask(fwd_opts->streamlocal_bind_mask); 3940 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3941 fwd_opts->streamlocal_bind_unlink); 3942 umask(omask); 3943 if (sock < 0) 3944 return 0; 3945 3946 debug("Local forwarding listening on path %s.", fwd->listen_path); 3947 3948 /* Allocate a channel number for the socket. */ 3949 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 3950 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3951 0, "unix listener", 1); 3952 c->path = xstrdup(path); 3953 c->host_port = port; 3954 c->listening_port = PORT_STREAMLOCAL; 3955 c->listening_addr = xstrdup(fwd->listen_path); 3956 return 1; 3957 } 3958 3959 static int 3960 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3961 const char *host, u_short port) 3962 { 3963 u_int i; 3964 int found = 0; 3965 3966 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3967 Channel *c = ssh->chanctxt->channels[i]; 3968 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3969 continue; 3970 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3971 debug2_f("close channel %d", i); 3972 channel_free(ssh, c); 3973 found = 1; 3974 } 3975 } 3976 3977 return found; 3978 } 3979 3980 static int 3981 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3982 { 3983 u_int i; 3984 int found = 0; 3985 3986 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3987 Channel *c = ssh->chanctxt->channels[i]; 3988 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3989 continue; 3990 if (c->path == NULL) 3991 continue; 3992 if (strcmp(c->path, path) == 0) { 3993 debug2_f("close channel %d", i); 3994 channel_free(ssh, c); 3995 found = 1; 3996 } 3997 } 3998 3999 return found; 4000 } 4001 4002 int 4003 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4004 { 4005 if (fwd->listen_path != NULL) { 4006 return channel_cancel_rport_listener_streamlocal(ssh, 4007 fwd->listen_path); 4008 } else { 4009 return channel_cancel_rport_listener_tcpip(ssh, 4010 fwd->listen_host, fwd->listen_port); 4011 } 4012 } 4013 4014 static int 4015 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4016 const char *lhost, u_short lport, int cport, 4017 struct ForwardOptions *fwd_opts) 4018 { 4019 u_int i; 4020 int found = 0; 4021 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4022 4023 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4024 Channel *c = ssh->chanctxt->channels[i]; 4025 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4026 continue; 4027 if (c->listening_port != lport) 4028 continue; 4029 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4030 /* skip dynamic forwardings */ 4031 if (c->host_port == 0) 4032 continue; 4033 } else { 4034 if (c->host_port != cport) 4035 continue; 4036 } 4037 if ((c->listening_addr == NULL && addr != NULL) || 4038 (c->listening_addr != NULL && addr == NULL)) 4039 continue; 4040 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4041 debug2_f("close channel %d", i); 4042 channel_free(ssh, c); 4043 found = 1; 4044 } 4045 } 4046 4047 return found; 4048 } 4049 4050 static int 4051 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4052 { 4053 u_int i; 4054 int found = 0; 4055 4056 if (path == NULL) { 4057 error_f("no path specified."); 4058 return 0; 4059 } 4060 4061 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4062 Channel *c = ssh->chanctxt->channels[i]; 4063 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4064 continue; 4065 if (c->listening_addr == NULL) 4066 continue; 4067 if (strcmp(c->listening_addr, path) == 0) { 4068 debug2_f("close channel %d", i); 4069 channel_free(ssh, c); 4070 found = 1; 4071 } 4072 } 4073 4074 return found; 4075 } 4076 4077 int 4078 channel_cancel_lport_listener(struct ssh *ssh, 4079 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4080 { 4081 if (fwd->listen_path != NULL) { 4082 return channel_cancel_lport_listener_streamlocal(ssh, 4083 fwd->listen_path); 4084 } else { 4085 return channel_cancel_lport_listener_tcpip(ssh, 4086 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4087 } 4088 } 4089 4090 /* protocol local port fwd, used by ssh */ 4091 int 4092 channel_setup_local_fwd_listener(struct ssh *ssh, 4093 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4094 { 4095 if (fwd->listen_path != NULL) { 4096 return channel_setup_fwd_listener_streamlocal(ssh, 4097 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4098 } else { 4099 return channel_setup_fwd_listener_tcpip(ssh, 4100 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4101 } 4102 } 4103 4104 /* Matches a remote forwarding permission against a requested forwarding */ 4105 static int 4106 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4107 { 4108 int ret; 4109 char *lhost; 4110 4111 /* XXX add ACLs for streamlocal */ 4112 if (fwd->listen_path != NULL) 4113 return 1; 4114 4115 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4116 return 0; 4117 4118 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4119 allowed_open->listen_port != fwd->listen_port) 4120 return 0; 4121 4122 /* Match hostnames case-insensitively */ 4123 lhost = xstrdup(fwd->listen_host); 4124 lowercase(lhost); 4125 ret = match_pattern(lhost, allowed_open->listen_host); 4126 free(lhost); 4127 4128 return ret; 4129 } 4130 4131 /* Checks whether a requested remote forwarding is permitted */ 4132 static int 4133 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4134 { 4135 struct ssh_channels *sc = ssh->chanctxt; 4136 struct permission_set *pset = &sc->remote_perms; 4137 u_int i, permit, permit_adm = 1; 4138 struct permission *perm; 4139 4140 /* XXX apply GatewayPorts override before checking? */ 4141 4142 permit = pset->all_permitted; 4143 if (!permit) { 4144 for (i = 0; i < pset->num_permitted_user; i++) { 4145 perm = &pset->permitted_user[i]; 4146 if (remote_open_match(perm, fwd)) { 4147 permit = 1; 4148 break; 4149 } 4150 } 4151 } 4152 4153 if (pset->num_permitted_admin > 0) { 4154 permit_adm = 0; 4155 for (i = 0; i < pset->num_permitted_admin; i++) { 4156 perm = &pset->permitted_admin[i]; 4157 if (remote_open_match(perm, fwd)) { 4158 permit_adm = 1; 4159 break; 4160 } 4161 } 4162 } 4163 4164 return permit && permit_adm; 4165 } 4166 4167 /* protocol v2 remote port fwd, used by sshd */ 4168 int 4169 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4170 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4171 { 4172 if (!check_rfwd_permission(ssh, fwd)) { 4173 ssh_packet_send_debug(ssh, "port forwarding refused"); 4174 if (fwd->listen_path != NULL) 4175 /* XXX always allowed, see remote_open_match() */ 4176 logit("Received request from %.100s port %d to " 4177 "remote forward to path \"%.100s\", " 4178 "but the request was denied.", 4179 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4180 fwd->listen_path); 4181 else if(fwd->listen_host != NULL) 4182 logit("Received request from %.100s port %d to " 4183 "remote forward to host %.100s port %d, " 4184 "but the request was denied.", 4185 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4186 fwd->listen_host, fwd->listen_port ); 4187 else 4188 logit("Received request from %.100s port %d to remote " 4189 "forward, but the request was denied.", 4190 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4191 return 0; 4192 } 4193 if (fwd->listen_path != NULL) { 4194 return channel_setup_fwd_listener_streamlocal(ssh, 4195 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4196 } else { 4197 return channel_setup_fwd_listener_tcpip(ssh, 4198 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4199 fwd_opts); 4200 } 4201 } 4202 4203 /* 4204 * Translate the requested rfwd listen host to something usable for 4205 * this server. 4206 */ 4207 static const char * 4208 channel_rfwd_bind_host(const char *listen_host) 4209 { 4210 if (listen_host == NULL) { 4211 return "localhost"; 4212 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4213 return ""; 4214 } else 4215 return listen_host; 4216 } 4217 4218 /* 4219 * Initiate forwarding of connections to port "port" on remote host through 4220 * the secure channel to host:port from local side. 4221 * Returns handle (index) for updating the dynamic listen port with 4222 * channel_update_permission(). 4223 */ 4224 int 4225 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4226 { 4227 int r, success = 0, idx = -1; 4228 const char *host_to_connect, *listen_host, *listen_path; 4229 int port_to_connect, listen_port; 4230 4231 /* Send the forward request to the remote side. */ 4232 if (fwd->listen_path != NULL) { 4233 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4234 (r = sshpkt_put_cstring(ssh, 4235 "streamlocal-forward@openssh.com")) != 0 || 4236 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4237 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4238 (r = sshpkt_send(ssh)) != 0 || 4239 (r = ssh_packet_write_wait(ssh)) < 0) 4240 fatal_fr(r, "request streamlocal"); 4241 } else { 4242 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4243 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4244 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4245 (r = sshpkt_put_cstring(ssh, 4246 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4247 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4248 (r = sshpkt_send(ssh)) != 0 || 4249 (r = ssh_packet_write_wait(ssh)) < 0) 4250 fatal_fr(r, "request tcpip-forward"); 4251 } 4252 /* Assume that server accepts the request */ 4253 success = 1; 4254 if (success) { 4255 /* Record that connection to this host/port is permitted. */ 4256 host_to_connect = listen_host = listen_path = NULL; 4257 port_to_connect = listen_port = 0; 4258 if (fwd->connect_path != NULL) { 4259 host_to_connect = fwd->connect_path; 4260 port_to_connect = PORT_STREAMLOCAL; 4261 } else { 4262 host_to_connect = fwd->connect_host; 4263 port_to_connect = fwd->connect_port; 4264 } 4265 if (fwd->listen_path != NULL) { 4266 listen_path = fwd->listen_path; 4267 listen_port = PORT_STREAMLOCAL; 4268 } else { 4269 listen_host = fwd->listen_host; 4270 listen_port = fwd->listen_port; 4271 } 4272 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4273 host_to_connect, port_to_connect, 4274 listen_host, listen_path, listen_port, NULL); 4275 } 4276 return idx; 4277 } 4278 4279 static int 4280 open_match(struct permission *allowed_open, const char *requestedhost, 4281 int requestedport) 4282 { 4283 if (allowed_open->host_to_connect == NULL) 4284 return 0; 4285 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4286 allowed_open->port_to_connect != requestedport) 4287 return 0; 4288 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4289 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4290 return 0; 4291 return 1; 4292 } 4293 4294 /* 4295 * Note that in the listen host/port case 4296 * we don't support FWD_PERMIT_ANY_PORT and 4297 * need to translate between the configured-host (listen_host) 4298 * and what we've sent to the remote server (channel_rfwd_bind_host) 4299 */ 4300 static int 4301 open_listen_match_tcpip(struct permission *allowed_open, 4302 const char *requestedhost, u_short requestedport, int translate) 4303 { 4304 const char *allowed_host; 4305 4306 if (allowed_open->host_to_connect == NULL) 4307 return 0; 4308 if (allowed_open->listen_port != requestedport) 4309 return 0; 4310 if (!translate && allowed_open->listen_host == NULL && 4311 requestedhost == NULL) 4312 return 1; 4313 allowed_host = translate ? 4314 channel_rfwd_bind_host(allowed_open->listen_host) : 4315 allowed_open->listen_host; 4316 if (allowed_host == NULL || requestedhost == NULL || 4317 strcmp(allowed_host, requestedhost) != 0) 4318 return 0; 4319 return 1; 4320 } 4321 4322 static int 4323 open_listen_match_streamlocal(struct permission *allowed_open, 4324 const char *requestedpath) 4325 { 4326 if (allowed_open->host_to_connect == NULL) 4327 return 0; 4328 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4329 return 0; 4330 if (allowed_open->listen_path == NULL || 4331 strcmp(allowed_open->listen_path, requestedpath) != 0) 4332 return 0; 4333 return 1; 4334 } 4335 4336 /* 4337 * Request cancellation of remote forwarding of connection host:port from 4338 * local side. 4339 */ 4340 static int 4341 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4342 const char *host, u_short port) 4343 { 4344 struct ssh_channels *sc = ssh->chanctxt; 4345 struct permission_set *pset = &sc->local_perms; 4346 int r; 4347 u_int i; 4348 struct permission *perm = NULL; 4349 4350 for (i = 0; i < pset->num_permitted_user; i++) { 4351 perm = &pset->permitted_user[i]; 4352 if (open_listen_match_tcpip(perm, host, port, 0)) 4353 break; 4354 perm = NULL; 4355 } 4356 if (perm == NULL) { 4357 debug_f("requested forward not found"); 4358 return -1; 4359 } 4360 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4361 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4362 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4363 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4364 (r = sshpkt_put_u32(ssh, port)) != 0 || 4365 (r = sshpkt_send(ssh)) != 0) 4366 fatal_fr(r, "send cancel"); 4367 4368 fwd_perm_clear(perm); /* unregister */ 4369 4370 return 0; 4371 } 4372 4373 /* 4374 * Request cancellation of remote forwarding of Unix domain socket 4375 * path from local side. 4376 */ 4377 static int 4378 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4379 { 4380 struct ssh_channels *sc = ssh->chanctxt; 4381 struct permission_set *pset = &sc->local_perms; 4382 int r; 4383 u_int i; 4384 struct permission *perm = NULL; 4385 4386 for (i = 0; i < pset->num_permitted_user; i++) { 4387 perm = &pset->permitted_user[i]; 4388 if (open_listen_match_streamlocal(perm, path)) 4389 break; 4390 perm = NULL; 4391 } 4392 if (perm == NULL) { 4393 debug_f("requested forward not found"); 4394 return -1; 4395 } 4396 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4397 (r = sshpkt_put_cstring(ssh, 4398 "cancel-streamlocal-forward@openssh.com")) != 0 || 4399 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4400 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4401 (r = sshpkt_send(ssh)) != 0) 4402 fatal_fr(r, "send cancel"); 4403 4404 fwd_perm_clear(perm); /* unregister */ 4405 4406 return 0; 4407 } 4408 4409 /* 4410 * Request cancellation of remote forwarding of a connection from local side. 4411 */ 4412 int 4413 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4414 { 4415 if (fwd->listen_path != NULL) { 4416 return channel_request_rforward_cancel_streamlocal(ssh, 4417 fwd->listen_path); 4418 } else { 4419 return channel_request_rforward_cancel_tcpip(ssh, 4420 fwd->listen_host, 4421 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4422 } 4423 } 4424 4425 /* 4426 * Permits opening to any host/port if permitted_user[] is empty. This is 4427 * usually called by the server, because the user could connect to any port 4428 * anyway, and the server has no way to know but to trust the client anyway. 4429 */ 4430 void 4431 channel_permit_all(struct ssh *ssh, int where) 4432 { 4433 struct permission_set *pset = permission_set_get(ssh, where); 4434 4435 if (pset->num_permitted_user == 0) 4436 pset->all_permitted = 1; 4437 } 4438 4439 /* 4440 * Permit the specified host/port for forwarding. 4441 */ 4442 void 4443 channel_add_permission(struct ssh *ssh, int who, int where, 4444 char *host, int port) 4445 { 4446 int local = where == FORWARD_LOCAL; 4447 struct permission_set *pset = permission_set_get(ssh, where); 4448 4449 debug("allow %s forwarding to host %s port %d", 4450 fwd_ident(who, where), host, port); 4451 /* 4452 * Remote forwards set listen_host/port, local forwards set 4453 * host/port_to_connect. 4454 */ 4455 permission_set_add(ssh, who, where, 4456 local ? host : 0, local ? port : 0, 4457 local ? NULL : host, NULL, local ? 0 : port, NULL); 4458 pset->all_permitted = 0; 4459 } 4460 4461 /* 4462 * Administratively disable forwarding. 4463 */ 4464 void 4465 channel_disable_admin(struct ssh *ssh, int where) 4466 { 4467 channel_clear_permission(ssh, FORWARD_ADM, where); 4468 permission_set_add(ssh, FORWARD_ADM, where, 4469 NULL, 0, NULL, NULL, 0, NULL); 4470 } 4471 4472 /* 4473 * Clear a list of permitted opens. 4474 */ 4475 void 4476 channel_clear_permission(struct ssh *ssh, int who, int where) 4477 { 4478 struct permission **permp; 4479 u_int *npermp; 4480 4481 permission_set_get_array(ssh, who, where, &permp, &npermp); 4482 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4483 *npermp = 0; 4484 } 4485 4486 /* 4487 * Update the listen port for a dynamic remote forward, after 4488 * the actual 'newport' has been allocated. If 'newport' < 0 is 4489 * passed then they entry will be invalidated. 4490 */ 4491 void 4492 channel_update_permission(struct ssh *ssh, int idx, int newport) 4493 { 4494 struct permission_set *pset = &ssh->chanctxt->local_perms; 4495 4496 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4497 debug_f("index out of range: %d num_permitted_user %d", 4498 idx, pset->num_permitted_user); 4499 return; 4500 } 4501 debug("%s allowed port %d for forwarding to host %s port %d", 4502 newport > 0 ? "Updating" : "Removing", 4503 newport, 4504 pset->permitted_user[idx].host_to_connect, 4505 pset->permitted_user[idx].port_to_connect); 4506 if (newport <= 0) 4507 fwd_perm_clear(&pset->permitted_user[idx]); 4508 else { 4509 pset->permitted_user[idx].listen_port = 4510 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4511 } 4512 } 4513 4514 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4515 int 4516 permitopen_port(const char *p) 4517 { 4518 int port; 4519 4520 if (strcmp(p, "*") == 0) 4521 return FWD_PERMIT_ANY_PORT; 4522 if ((port = a2port(p)) > 0) 4523 return port; 4524 return -1; 4525 } 4526 4527 /* Try to start non-blocking connect to next host in cctx list */ 4528 static int 4529 connect_next(struct channel_connect *cctx) 4530 { 4531 int sock, saved_errno; 4532 struct sockaddr_un *sunaddr; 4533 char ntop[NI_MAXHOST]; 4534 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4535 4536 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4537 switch (cctx->ai->ai_family) { 4538 case AF_UNIX: 4539 /* unix:pathname instead of host:port */ 4540 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4541 strlcpy(ntop, "unix", sizeof(ntop)); 4542 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4543 break; 4544 case AF_INET: 4545 case AF_INET6: 4546 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4547 ntop, sizeof(ntop), strport, sizeof(strport), 4548 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4549 error_f("getnameinfo failed"); 4550 continue; 4551 } 4552 break; 4553 default: 4554 continue; 4555 } 4556 debug_f("start for host %.100s ([%.100s]:%s)", 4557 cctx->host, ntop, strport); 4558 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4559 cctx->ai->ai_protocol)) == -1) { 4560 if (cctx->ai->ai_next == NULL) 4561 error("socket: %.100s", strerror(errno)); 4562 else 4563 verbose("socket: %.100s", strerror(errno)); 4564 continue; 4565 } 4566 if (set_nonblock(sock) == -1) 4567 fatal_f("set_nonblock(%d)", sock); 4568 if (connect(sock, cctx->ai->ai_addr, 4569 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4570 debug_f("host %.100s ([%.100s]:%s): %.100s", 4571 cctx->host, ntop, strport, strerror(errno)); 4572 saved_errno = errno; 4573 close(sock); 4574 errno = saved_errno; 4575 continue; /* fail -- try next */ 4576 } 4577 if (cctx->ai->ai_family != AF_UNIX) 4578 set_nodelay(sock); 4579 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4580 cctx->host, ntop, strport, sock); 4581 cctx->ai = cctx->ai->ai_next; 4582 return sock; 4583 } 4584 return -1; 4585 } 4586 4587 static void 4588 channel_connect_ctx_free(struct channel_connect *cctx) 4589 { 4590 free(cctx->host); 4591 if (cctx->aitop) { 4592 if (cctx->aitop->ai_family == AF_UNIX) 4593 free(cctx->aitop); 4594 else 4595 freeaddrinfo(cctx->aitop); 4596 } 4597 memset(cctx, 0, sizeof(*cctx)); 4598 } 4599 4600 /* 4601 * Return connecting socket to remote host:port or local socket path, 4602 * passing back the failure reason if appropriate. 4603 */ 4604 static int 4605 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4606 const char *ctype, const char *rname, struct channel_connect *cctx, 4607 int *reason, const char **errmsg) 4608 { 4609 struct addrinfo hints; 4610 int gaierr; 4611 int sock = -1; 4612 char strport[NI_MAXSERV]; 4613 4614 if (port == PORT_STREAMLOCAL) { 4615 struct sockaddr_un *sunaddr; 4616 struct addrinfo *ai; 4617 4618 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4619 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4620 return -1; 4621 } 4622 4623 /* 4624 * Fake up a struct addrinfo for AF_UNIX connections. 4625 * channel_connect_ctx_free() must check ai_family 4626 * and use free() not freeaddirinfo() for AF_UNIX. 4627 */ 4628 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4629 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4630 ai->ai_addr = (struct sockaddr *)(ai + 1); 4631 ai->ai_addrlen = sizeof(*sunaddr); 4632 ai->ai_family = AF_UNIX; 4633 ai->ai_socktype = socktype; 4634 ai->ai_protocol = PF_UNSPEC; 4635 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4636 sunaddr->sun_family = AF_UNIX; 4637 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4638 cctx->aitop = ai; 4639 } else { 4640 memset(&hints, 0, sizeof(hints)); 4641 hints.ai_family = ssh->chanctxt->IPv4or6; 4642 hints.ai_socktype = socktype; 4643 snprintf(strport, sizeof strport, "%d", port); 4644 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4645 != 0) { 4646 if (errmsg != NULL) 4647 *errmsg = ssh_gai_strerror(gaierr); 4648 if (reason != NULL) 4649 *reason = SSH2_OPEN_CONNECT_FAILED; 4650 error("connect_to %.100s: unknown host (%s)", name, 4651 ssh_gai_strerror(gaierr)); 4652 return -1; 4653 } 4654 } 4655 4656 cctx->host = xstrdup(name); 4657 cctx->port = port; 4658 cctx->ai = cctx->aitop; 4659 4660 if ((sock = connect_next(cctx)) == -1) { 4661 error("connect to %.100s port %d failed: %s", 4662 name, port, strerror(errno)); 4663 return -1; 4664 } 4665 4666 return sock; 4667 } 4668 4669 /* Return CONNECTING channel to remote host:port or local socket path */ 4670 static Channel * 4671 connect_to(struct ssh *ssh, const char *host, int port, 4672 const char *ctype, const char *rname) 4673 { 4674 struct channel_connect cctx; 4675 Channel *c; 4676 int sock; 4677 4678 memset(&cctx, 0, sizeof(cctx)); 4679 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4680 &cctx, NULL, NULL); 4681 if (sock == -1) { 4682 channel_connect_ctx_free(&cctx); 4683 return NULL; 4684 } 4685 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4686 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4687 c->host_port = port; 4688 c->path = xstrdup(host); 4689 c->connect_ctx = cctx; 4690 4691 return c; 4692 } 4693 4694 /* 4695 * returns either the newly connected channel or the downstream channel 4696 * that needs to deal with this connection. 4697 */ 4698 Channel * 4699 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4700 u_short listen_port, const char *ctype, const char *rname) 4701 { 4702 struct ssh_channels *sc = ssh->chanctxt; 4703 struct permission_set *pset = &sc->local_perms; 4704 u_int i; 4705 struct permission *perm; 4706 4707 for (i = 0; i < pset->num_permitted_user; i++) { 4708 perm = &pset->permitted_user[i]; 4709 if (open_listen_match_tcpip(perm, 4710 listen_host, listen_port, 1)) { 4711 if (perm->downstream) 4712 return perm->downstream; 4713 if (perm->port_to_connect == 0) 4714 return rdynamic_connect_prepare(ssh, 4715 ctype, rname); 4716 return connect_to(ssh, 4717 perm->host_to_connect, perm->port_to_connect, 4718 ctype, rname); 4719 } 4720 } 4721 error("WARNING: Server requests forwarding for unknown listen_port %d", 4722 listen_port); 4723 return NULL; 4724 } 4725 4726 Channel * 4727 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4728 const char *ctype, const char *rname) 4729 { 4730 struct ssh_channels *sc = ssh->chanctxt; 4731 struct permission_set *pset = &sc->local_perms; 4732 u_int i; 4733 struct permission *perm; 4734 4735 for (i = 0; i < pset->num_permitted_user; i++) { 4736 perm = &pset->permitted_user[i]; 4737 if (open_listen_match_streamlocal(perm, path)) { 4738 return connect_to(ssh, 4739 perm->host_to_connect, perm->port_to_connect, 4740 ctype, rname); 4741 } 4742 } 4743 error("WARNING: Server requests forwarding for unknown path %.100s", 4744 path); 4745 return NULL; 4746 } 4747 4748 /* Check if connecting to that port is permitted and connect. */ 4749 Channel * 4750 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4751 const char *ctype, const char *rname, int *reason, const char **errmsg) 4752 { 4753 struct ssh_channels *sc = ssh->chanctxt; 4754 struct permission_set *pset = &sc->local_perms; 4755 struct channel_connect cctx; 4756 Channel *c; 4757 u_int i, permit, permit_adm = 1; 4758 int sock; 4759 struct permission *perm; 4760 4761 permit = pset->all_permitted; 4762 if (!permit) { 4763 for (i = 0; i < pset->num_permitted_user; i++) { 4764 perm = &pset->permitted_user[i]; 4765 if (open_match(perm, host, port)) { 4766 permit = 1; 4767 break; 4768 } 4769 } 4770 } 4771 4772 if (pset->num_permitted_admin > 0) { 4773 permit_adm = 0; 4774 for (i = 0; i < pset->num_permitted_admin; i++) { 4775 perm = &pset->permitted_admin[i]; 4776 if (open_match(perm, host, port)) { 4777 permit_adm = 1; 4778 break; 4779 } 4780 } 4781 } 4782 4783 if (!permit || !permit_adm) { 4784 logit("Received request from %.100s port %d to connect to " 4785 "host %.100s port %d, but the request was denied.", 4786 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4787 if (reason != NULL) 4788 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4789 return NULL; 4790 } 4791 4792 memset(&cctx, 0, sizeof(cctx)); 4793 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4794 &cctx, reason, errmsg); 4795 if (sock == -1) { 4796 channel_connect_ctx_free(&cctx); 4797 return NULL; 4798 } 4799 4800 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4801 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4802 c->host_port = port; 4803 c->path = xstrdup(host); 4804 c->connect_ctx = cctx; 4805 4806 return c; 4807 } 4808 4809 /* Check if connecting to that path is permitted and connect. */ 4810 Channel * 4811 channel_connect_to_path(struct ssh *ssh, const char *path, const char *ctype, 4812 const char *rname) 4813 { 4814 struct ssh_channels *sc = ssh->chanctxt; 4815 struct permission_set *pset = &sc->local_perms; 4816 u_int i, permit, permit_adm = 1; 4817 struct permission *perm; 4818 4819 permit = pset->all_permitted; 4820 if (!permit) { 4821 for (i = 0; i < pset->num_permitted_user; i++) { 4822 perm = &pset->permitted_user[i]; 4823 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4824 permit = 1; 4825 break; 4826 } 4827 } 4828 } 4829 4830 if (pset->num_permitted_admin > 0) { 4831 permit_adm = 0; 4832 for (i = 0; i < pset->num_permitted_admin; i++) { 4833 perm = &pset->permitted_admin[i]; 4834 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4835 permit_adm = 1; 4836 break; 4837 } 4838 } 4839 } 4840 4841 if (!permit || !permit_adm) { 4842 logit("Received request to connect to path %.100s, " 4843 "but the request was denied.", path); 4844 return NULL; 4845 } 4846 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4847 } 4848 4849 void 4850 channel_send_window_changes(struct ssh *ssh) 4851 { 4852 struct ssh_channels *sc = ssh->chanctxt; 4853 struct winsize ws; 4854 int r; 4855 u_int i; 4856 4857 for (i = 0; i < sc->channels_alloc; i++) { 4858 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4859 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4860 continue; 4861 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4862 continue; 4863 channel_request_start(ssh, i, "window-change", 0); 4864 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4865 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4866 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4867 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4868 (r = sshpkt_send(ssh)) != 0) 4869 fatal_fr(r, "channel %u; send window-change", i); 4870 } 4871 } 4872 4873 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4874 static Channel * 4875 rdynamic_connect_prepare(struct ssh *ssh, const char *ctype, const char *rname) 4876 { 4877 Channel *c; 4878 int r; 4879 4880 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4881 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4882 c->host_port = 0; 4883 c->path = NULL; 4884 4885 /* 4886 * We need to open the channel before we have a FD, 4887 * so that we can get SOCKS header from peer. 4888 */ 4889 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4890 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4891 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4892 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4893 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4894 fatal_fr(r, "channel %i; confirm", c->self); 4895 return c; 4896 } 4897 4898 /* Return CONNECTING socket to remote host:port or local socket path */ 4899 static int 4900 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4901 { 4902 struct ssh_channels *sc = ssh->chanctxt; 4903 struct permission_set *pset = &sc->local_perms; 4904 struct permission *perm; 4905 struct channel_connect cctx; 4906 u_int i, permit_adm = 1; 4907 int sock; 4908 4909 if (pset->num_permitted_admin > 0) { 4910 permit_adm = 0; 4911 for (i = 0; i < pset->num_permitted_admin; i++) { 4912 perm = &pset->permitted_admin[i]; 4913 if (open_match(perm, c->path, c->host_port)) { 4914 permit_adm = 1; 4915 break; 4916 } 4917 } 4918 } 4919 if (!permit_adm) { 4920 debug_f("requested forward not permitted"); 4921 return -1; 4922 } 4923 4924 memset(&cctx, 0, sizeof(cctx)); 4925 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4926 NULL, &cctx, NULL, NULL); 4927 if (sock == -1) 4928 channel_connect_ctx_free(&cctx); 4929 else { 4930 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4931 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4932 c->connect_ctx = cctx; 4933 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4934 } 4935 return sock; 4936 } 4937 4938 /* -- X11 forwarding */ 4939 4940 /* 4941 * Creates an internet domain socket for listening for X11 connections. 4942 * Returns 0 and a suitable display number for the DISPLAY variable 4943 * stored in display_numberp , or -1 if an error occurs. 4944 */ 4945 int 4946 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4947 int x11_use_localhost, int single_connection, 4948 u_int *display_numberp, int **chanids) 4949 { 4950 Channel *nc = NULL; 4951 int display_number, sock; 4952 u_short port; 4953 struct addrinfo hints, *ai, *aitop; 4954 char strport[NI_MAXSERV]; 4955 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4956 4957 if (chanids == NULL) 4958 return -1; 4959 4960 for (display_number = x11_display_offset; 4961 display_number < MAX_DISPLAYS; 4962 display_number++) { 4963 port = 6000 + display_number; 4964 memset(&hints, 0, sizeof(hints)); 4965 hints.ai_family = ssh->chanctxt->IPv4or6; 4966 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4967 hints.ai_socktype = SOCK_STREAM; 4968 snprintf(strport, sizeof strport, "%d", port); 4969 if ((gaierr = getaddrinfo(NULL, strport, 4970 &hints, &aitop)) != 0) { 4971 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4972 return -1; 4973 } 4974 for (ai = aitop; ai; ai = ai->ai_next) { 4975 if (ai->ai_family != AF_INET && 4976 ai->ai_family != AF_INET6) 4977 continue; 4978 sock = socket(ai->ai_family, ai->ai_socktype, 4979 ai->ai_protocol); 4980 if (sock == -1) { 4981 error("socket: %.100s", strerror(errno)); 4982 freeaddrinfo(aitop); 4983 return -1; 4984 } 4985 set_reuseaddr(sock); 4986 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4987 debug2_f("bind port %d: %.100s", port, 4988 strerror(errno)); 4989 close(sock); 4990 for (n = 0; n < num_socks; n++) 4991 close(socks[n]); 4992 num_socks = 0; 4993 break; 4994 } 4995 socks[num_socks++] = sock; 4996 if (num_socks == NUM_SOCKS) 4997 break; 4998 } 4999 freeaddrinfo(aitop); 5000 if (num_socks > 0) 5001 break; 5002 } 5003 if (display_number >= MAX_DISPLAYS) { 5004 error("Failed to allocate internet-domain X11 display socket."); 5005 return -1; 5006 } 5007 /* Start listening for connections on the socket. */ 5008 for (n = 0; n < num_socks; n++) { 5009 sock = socks[n]; 5010 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5011 error("listen: %.100s", strerror(errno)); 5012 close(sock); 5013 return -1; 5014 } 5015 } 5016 5017 /* Allocate a channel for each socket. */ 5018 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5019 for (n = 0; n < num_socks; n++) { 5020 sock = socks[n]; 5021 /* Is this really necassary? */ 5022 if (hpn_disabled) 5023 nc = channel_new(ssh, "x11-listener", 5024 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5025 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5026 0, "X11 inet listener", 1); 5027 else 5028 nc = channel_new(ssh, "x11 listener", 5029 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5030 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 5031 0, "X11 inet listener", 1); 5032 nc->single_connection = single_connection; 5033 (*chanids)[n] = nc->self; 5034 } 5035 (*chanids)[n] = -1; 5036 5037 /* Return the display number for the DISPLAY environment variable. */ 5038 *display_numberp = display_number; 5039 return 0; 5040 } 5041 5042 static int 5043 connect_local_xsocket(u_int dnr) 5044 { 5045 int sock; 5046 struct sockaddr_un addr; 5047 5048 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5049 if (sock == -1) 5050 error("socket: %.100s", strerror(errno)); 5051 memset(&addr, 0, sizeof(addr)); 5052 addr.sun_family = AF_UNIX; 5053 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 5054 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5055 return sock; 5056 close(sock); 5057 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5058 return -1; 5059 } 5060 5061 int 5062 x11_connect_display(struct ssh *ssh) 5063 { 5064 u_int display_number; 5065 const char *display; 5066 char buf[1024], *cp; 5067 struct addrinfo hints, *ai, *aitop; 5068 char strport[NI_MAXSERV]; 5069 int gaierr, sock = 0; 5070 5071 /* Try to open a socket for the local X server. */ 5072 display = getenv("DISPLAY"); 5073 if (!display) { 5074 error("DISPLAY not set."); 5075 return -1; 5076 } 5077 /* 5078 * Now we decode the value of the DISPLAY variable and make a 5079 * connection to the real X server. 5080 */ 5081 5082 /* 5083 * Check if it is a unix domain socket. Unix domain displays are in 5084 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5085 */ 5086 if (strncmp(display, "unix:", 5) == 0 || 5087 display[0] == ':') { 5088 /* Connect to the unix domain socket. */ 5089 if (sscanf(strrchr(display, ':') + 1, "%u", 5090 &display_number) != 1) { 5091 error("Could not parse display number from DISPLAY: " 5092 "%.100s", display); 5093 return -1; 5094 } 5095 /* Create a socket. */ 5096 sock = connect_local_xsocket(display_number); 5097 if (sock < 0) 5098 return -1; 5099 5100 /* OK, we now have a connection to the display. */ 5101 return sock; 5102 } 5103 /* 5104 * Connect to an inet socket. The DISPLAY value is supposedly 5105 * hostname:d[.s], where hostname may also be numeric IP address. 5106 */ 5107 strlcpy(buf, display, sizeof(buf)); 5108 cp = strchr(buf, ':'); 5109 if (!cp) { 5110 error("Could not find ':' in DISPLAY: %.100s", display); 5111 return -1; 5112 } 5113 *cp = 0; 5114 /* 5115 * buf now contains the host name. But first we parse the 5116 * display number. 5117 */ 5118 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5119 error("Could not parse display number from DISPLAY: %.100s", 5120 display); 5121 return -1; 5122 } 5123 5124 /* Look up the host address */ 5125 memset(&hints, 0, sizeof(hints)); 5126 hints.ai_family = ssh->chanctxt->IPv4or6; 5127 hints.ai_socktype = SOCK_STREAM; 5128 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5129 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5130 error("%.100s: unknown host. (%s)", buf, 5131 ssh_gai_strerror(gaierr)); 5132 return -1; 5133 } 5134 for (ai = aitop; ai; ai = ai->ai_next) { 5135 /* Create a socket. */ 5136 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5137 if (sock == -1) { 5138 debug2("socket: %.100s", strerror(errno)); 5139 continue; 5140 } 5141 /* Connect it to the display. */ 5142 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5143 debug2("connect %.100s port %u: %.100s", buf, 5144 6000 + display_number, strerror(errno)); 5145 close(sock); 5146 continue; 5147 } 5148 /* Success */ 5149 break; 5150 } 5151 freeaddrinfo(aitop); 5152 if (!ai) { 5153 error("connect %.100s port %u: %.100s", buf, 5154 6000 + display_number, strerror(errno)); 5155 return -1; 5156 } 5157 set_nodelay(sock); 5158 return sock; 5159 } 5160 5161 /* 5162 * Requests forwarding of X11 connections, generates fake authentication 5163 * data, and enables authentication spoofing. 5164 * This should be called in the client only. 5165 */ 5166 void 5167 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5168 const char *disp, const char *proto, const char *data, int want_reply) 5169 { 5170 struct ssh_channels *sc = ssh->chanctxt; 5171 u_int data_len = (u_int) strlen(data) / 2; 5172 u_int i, value; 5173 const char *cp; 5174 char *new_data; 5175 int r, screen_number; 5176 5177 if (sc->x11_saved_display == NULL) 5178 sc->x11_saved_display = xstrdup(disp); 5179 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5180 error("x11_request_forwarding_with_spoofing: different " 5181 "$DISPLAY already forwarded"); 5182 return; 5183 } 5184 5185 cp = strchr(disp, ':'); 5186 if (cp) 5187 cp = strchr(cp, '.'); 5188 if (cp) 5189 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5190 else 5191 screen_number = 0; 5192 5193 if (sc->x11_saved_proto == NULL) { 5194 /* Save protocol name. */ 5195 sc->x11_saved_proto = xstrdup(proto); 5196 5197 /* Extract real authentication data. */ 5198 sc->x11_saved_data = xmalloc(data_len); 5199 for (i = 0; i < data_len; i++) { 5200 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5201 fatal("x11_request_forwarding: bad " 5202 "authentication data: %.100s", data); 5203 } 5204 sc->x11_saved_data[i] = value; 5205 } 5206 sc->x11_saved_data_len = data_len; 5207 5208 /* Generate fake data of the same length. */ 5209 sc->x11_fake_data = xmalloc(data_len); 5210 arc4random_buf(sc->x11_fake_data, data_len); 5211 sc->x11_fake_data_len = data_len; 5212 } 5213 5214 /* Convert the fake data into hex. */ 5215 new_data = tohex(sc->x11_fake_data, data_len); 5216 5217 /* Send the request packet. */ 5218 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5219 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5220 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5221 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5222 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5223 (r = sshpkt_send(ssh)) != 0 || 5224 (r = ssh_packet_write_wait(ssh)) < 0) 5225 fatal_fr(r, "send x11-req"); 5226 free(new_data); 5227 } 5228