1 /* $OpenBSD: channels.c,v 1.442 2024/12/05 06:49:26 dtucker Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 #include <sys/ioctl.h> 45 #include <sys/un.h> 46 #include <sys/socket.h> 47 #include <sys/time.h> 48 #include <sys/queue.h> 49 50 #include <netinet/in.h> 51 #include <arpa/inet.h> 52 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <limits.h> 56 #include <netdb.h> 57 #include <poll.h> 58 #include <stdarg.h> 59 #include <stdint.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <termios.h> 64 #include <unistd.h> 65 66 #include "xmalloc.h" 67 #include "ssh.h" 68 #include "ssh2.h" 69 #include "ssherr.h" 70 #include "sshbuf.h" 71 #include "packet.h" 72 #include "log.h" 73 #include "misc.h" 74 #include "channels.h" 75 #include "compat.h" 76 #include "canohost.h" 77 #include "sshkey.h" 78 #include "authfd.h" 79 #include "pathnames.h" 80 #include "match.h" 81 82 /* XXX remove once we're satisfied there's no lurking bugs */ 83 /* #define DEBUG_CHANNEL_POLL 1 */ 84 85 /* -- agent forwarding */ 86 #define NUM_SOCKS 10 87 88 /* -- X11 forwarding */ 89 /* X11 port for display :0 */ 90 #define X11_BASE_PORT 6000 91 /* Maximum number of fake X11 displays to try. */ 92 #define MAX_DISPLAYS 1000 93 94 /* Per-channel callback for pre/post IO actions */ 95 typedef void chan_fn(struct ssh *, Channel *c); 96 97 /* 98 * Data structure for storing which hosts are permitted for forward requests. 99 * The local sides of any remote forwards are stored in this array to prevent 100 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 101 * network (which might be behind a firewall). 102 */ 103 /* XXX: streamlocal wants a path instead of host:port */ 104 /* Overload host_to_connect; we could just make this match Forward */ 105 /* XXX - can we use listen_host instead of listen_path? */ 106 struct permission { 107 char *host_to_connect; /* Connect to 'host'. */ 108 int port_to_connect; /* Connect to 'port'. */ 109 char *listen_host; /* Remote side should listen address. */ 110 char *listen_path; /* Remote side should listen path. */ 111 int listen_port; /* Remote side should listen port. */ 112 Channel *downstream; /* Downstream mux*/ 113 }; 114 115 /* 116 * Stores the forwarding permission state for a single direction (local or 117 * remote). 118 */ 119 struct permission_set { 120 /* 121 * List of all local permitted host/port pairs to allow for the 122 * user. 123 */ 124 u_int num_permitted_user; 125 struct permission *permitted_user; 126 127 /* 128 * List of all permitted host/port pairs to allow for the admin. 129 */ 130 u_int num_permitted_admin; 131 struct permission *permitted_admin; 132 133 /* 134 * If this is true, all opens/listens are permitted. This is the 135 * case on the server on which we have to trust the client anyway, 136 * and the user could do anything after logging in. 137 */ 138 int all_permitted; 139 }; 140 141 /* Used to record timeouts per channel type */ 142 struct ssh_channel_timeout { 143 char *type_pattern; 144 int timeout_secs; 145 }; 146 147 /* Master structure for channels state */ 148 struct ssh_channels { 149 /* 150 * Pointer to an array containing all allocated channels. The array 151 * is dynamically extended as needed. 152 */ 153 Channel **channels; 154 155 /* 156 * Size of the channel array. All slots of the array must always be 157 * initialized (at least the type field); unused slots set to NULL 158 */ 159 u_int channels_alloc; 160 161 /* 162 * 'channel_pre*' are called just before IO to add any bits 163 * relevant to channels in the c->io_want bitmasks. 164 * 165 * 'channel_post*': perform any appropriate operations for 166 * channels which have c->io_ready events pending. 167 */ 168 chan_fn **channel_pre; 169 chan_fn **channel_post; 170 171 /* -- tcp forwarding */ 172 struct permission_set local_perms; 173 struct permission_set remote_perms; 174 175 /* -- X11 forwarding */ 176 177 /* Saved X11 local (client) display. */ 178 char *x11_saved_display; 179 180 /* Saved X11 authentication protocol name. */ 181 char *x11_saved_proto; 182 183 /* Saved X11 authentication data. This is the real data. */ 184 char *x11_saved_data; 185 u_int x11_saved_data_len; 186 187 /* Deadline after which all X11 connections are refused */ 188 time_t x11_refuse_time; 189 190 /* 191 * Fake X11 authentication data. This is what the server will be 192 * sending us; we should replace any occurrences of this by the 193 * real data. 194 */ 195 u_char *x11_fake_data; 196 u_int x11_fake_data_len; 197 198 /* AF_UNSPEC or AF_INET or AF_INET6 */ 199 int IPv4or6; 200 201 /* Channel timeouts by type */ 202 struct ssh_channel_timeout *timeouts; 203 size_t ntimeouts; 204 /* Global timeout for all OPEN channels */ 205 int global_deadline; 206 time_t lastused; 207 }; 208 209 /* helper */ 210 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 211 static const char *channel_rfwd_bind_host(const char *listen_host); 212 213 /* non-blocking connect helpers */ 214 static int connect_next(struct channel_connect *); 215 static void channel_connect_ctx_free(struct channel_connect *); 216 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 217 static int rdynamic_connect_finish(struct ssh *, Channel *); 218 219 /* Setup helper */ 220 static void channel_handler_init(struct ssh_channels *sc); 221 222 /* -- channel core */ 223 224 void 225 channel_init_channels(struct ssh *ssh) 226 { 227 struct ssh_channels *sc; 228 229 if ((sc = calloc(1, sizeof(*sc))) == NULL) 230 fatal_f("allocation failed"); 231 sc->channels_alloc = 10; 232 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 233 sc->IPv4or6 = AF_UNSPEC; 234 channel_handler_init(sc); 235 236 ssh->chanctxt = sc; 237 } 238 239 Channel * 240 channel_by_id(struct ssh *ssh, int id) 241 { 242 Channel *c; 243 244 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 245 logit_f("%d: bad id", id); 246 return NULL; 247 } 248 c = ssh->chanctxt->channels[id]; 249 if (c == NULL) { 250 logit_f("%d: bad id: channel free", id); 251 return NULL; 252 } 253 return c; 254 } 255 256 Channel * 257 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 258 { 259 Channel *c; 260 u_int i; 261 262 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 263 c = ssh->chanctxt->channels[i]; 264 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 265 return c; 266 } 267 return NULL; 268 } 269 270 /* 271 * Returns the channel if it is allowed to receive protocol messages. 272 * Private channels, like listening sockets, may not receive messages. 273 */ 274 Channel * 275 channel_lookup(struct ssh *ssh, int id) 276 { 277 Channel *c; 278 279 if ((c = channel_by_id(ssh, id)) == NULL) 280 return NULL; 281 282 switch (c->type) { 283 case SSH_CHANNEL_X11_OPEN: 284 case SSH_CHANNEL_LARVAL: 285 case SSH_CHANNEL_CONNECTING: 286 case SSH_CHANNEL_DYNAMIC: 287 case SSH_CHANNEL_RDYNAMIC_OPEN: 288 case SSH_CHANNEL_RDYNAMIC_FINISH: 289 case SSH_CHANNEL_OPENING: 290 case SSH_CHANNEL_OPEN: 291 case SSH_CHANNEL_ABANDONED: 292 case SSH_CHANNEL_MUX_PROXY: 293 return c; 294 } 295 logit("Non-public channel %d, type %d.", id, c->type); 296 return NULL; 297 } 298 299 /* 300 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 301 * match type_pattern. 302 */ 303 void 304 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 305 int timeout_secs) 306 { 307 struct ssh_channels *sc = ssh->chanctxt; 308 309 if (strcmp(type_pattern, "global") == 0) { 310 debug2_f("global channel timeout %d seconds", timeout_secs); 311 sc->global_deadline = timeout_secs; 312 return; 313 } 314 debug2_f("channel type \"%s\" timeout %d seconds", 315 type_pattern, timeout_secs); 316 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 317 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 318 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 319 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 320 sc->ntimeouts++; 321 } 322 323 /* Clears all previously-added channel timeouts */ 324 void 325 channel_clear_timeouts(struct ssh *ssh) 326 { 327 struct ssh_channels *sc = ssh->chanctxt; 328 size_t i; 329 330 debug3_f("clearing"); 331 for (i = 0; i < sc->ntimeouts; i++) 332 free(sc->timeouts[i].type_pattern); 333 free(sc->timeouts); 334 sc->timeouts = NULL; 335 sc->ntimeouts = 0; 336 } 337 338 static int 339 lookup_timeout(struct ssh *ssh, const char *type) 340 { 341 struct ssh_channels *sc = ssh->chanctxt; 342 size_t i; 343 344 for (i = 0; i < sc->ntimeouts; i++) { 345 if (match_pattern(type, sc->timeouts[i].type_pattern)) 346 return sc->timeouts[i].timeout_secs; 347 } 348 349 return 0; 350 } 351 352 /* 353 * Sets "extended type" of a channel; used by session layer to add additional 354 * information about channel types (e.g. shell, login, subsystem) that can then 355 * be used to select timeouts. 356 * Will reset c->inactive_deadline as a side-effect. 357 */ 358 void 359 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 360 { 361 Channel *c; 362 363 if ((c = channel_by_id(ssh, id)) == NULL) 364 fatal_f("missing channel %d", id); 365 if (c->xctype != NULL) 366 free(c->xctype); 367 c->xctype = xstrdup(xctype); 368 /* Type has changed, so look up inactivity deadline again */ 369 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 370 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 371 c->inactive_deadline); 372 } 373 374 /* 375 * update "last used" time on a channel. 376 * NB. nothing else should update lastused except to clear it. 377 */ 378 static void 379 channel_set_used_time(struct ssh *ssh, Channel *c) 380 { 381 ssh->chanctxt->lastused = monotime(); 382 if (c != NULL) 383 c->lastused = ssh->chanctxt->lastused; 384 } 385 386 /* 387 * Get the time at which a channel is due to time out for inactivity. 388 * Returns 0 if the channel is not due to time out ever. 389 */ 390 static time_t 391 channel_get_expiry(struct ssh *ssh, Channel *c) 392 { 393 struct ssh_channels *sc = ssh->chanctxt; 394 time_t expiry = 0, channel_expiry; 395 396 if (sc->lastused != 0 && sc->global_deadline != 0) 397 expiry = sc->lastused + sc->global_deadline; 398 if (c->lastused != 0 && c->inactive_deadline != 0) { 399 channel_expiry = c->lastused + c->inactive_deadline; 400 if (expiry == 0 || channel_expiry < expiry) 401 expiry = channel_expiry; 402 } 403 return expiry; 404 } 405 406 /* 407 * Register filedescriptors for a channel, used when allocating a channel or 408 * when the channel consumer/producer is ready, e.g. shell exec'd 409 */ 410 static void 411 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 412 int extusage, int nonblock, int is_tty) 413 { 414 int val; 415 416 if (rfd != -1) 417 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 418 if (wfd != -1 && wfd != rfd) 419 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 420 if (efd != -1 && efd != rfd && efd != wfd) 421 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 422 423 c->rfd = rfd; 424 c->wfd = wfd; 425 c->sock = (rfd == wfd) ? rfd : -1; 426 c->efd = efd; 427 c->extended_usage = extusage; 428 429 if ((c->isatty = is_tty) != 0) 430 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 431 432 /* enable nonblocking mode */ 433 c->restore_block = 0; 434 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 435 /* 436 * Special handling for stdio file descriptors: do not set 437 * non-blocking mode if they are TTYs. Otherwise prepare to 438 * restore their blocking state on exit to avoid interfering 439 * with other programs that follow. 440 */ 441 if (rfd != -1 && !isatty(rfd) && 442 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 443 c->restore_flags[0] = val; 444 c->restore_block |= CHANNEL_RESTORE_RFD; 445 set_nonblock(rfd); 446 } 447 if (wfd != -1 && !isatty(wfd) && 448 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 449 c->restore_flags[1] = val; 450 c->restore_block |= CHANNEL_RESTORE_WFD; 451 set_nonblock(wfd); 452 } 453 if (efd != -1 && !isatty(efd) && 454 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 455 c->restore_flags[2] = val; 456 c->restore_block |= CHANNEL_RESTORE_EFD; 457 set_nonblock(efd); 458 } 459 } else if (nonblock) { 460 if (rfd != -1) 461 set_nonblock(rfd); 462 if (wfd != -1) 463 set_nonblock(wfd); 464 if (efd != -1) 465 set_nonblock(efd); 466 } 467 /* channel might be entering a larval state, so reset global timeout */ 468 channel_set_used_time(ssh, NULL); 469 } 470 471 /* 472 * Allocate a new channel object and set its type and socket. 473 */ 474 Channel * 475 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 476 u_int window, u_int maxpack, int extusage, const char *remote_name, 477 int nonblock) 478 { 479 struct ssh_channels *sc = ssh->chanctxt; 480 u_int i, found; 481 Channel *c; 482 int r; 483 484 /* Try to find a free slot where to put the new channel. */ 485 for (i = 0; i < sc->channels_alloc; i++) { 486 if (sc->channels[i] == NULL) { 487 /* Found a free slot. */ 488 found = i; 489 break; 490 } 491 } 492 if (i >= sc->channels_alloc) { 493 /* 494 * There are no free slots. Take last+1 slot and expand 495 * the array. 496 */ 497 found = sc->channels_alloc; 498 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 499 fatal_f("internal error: channels_alloc %d too big", 500 sc->channels_alloc); 501 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 502 sc->channels_alloc + 10, sizeof(*sc->channels)); 503 sc->channels_alloc += 10; 504 debug2("channel: expanding %d", sc->channels_alloc); 505 } 506 /* Initialize and return new channel. */ 507 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 508 if ((c->input = sshbuf_new()) == NULL || 509 (c->output = sshbuf_new()) == NULL || 510 (c->extended = sshbuf_new()) == NULL) 511 fatal_f("sshbuf_new failed"); 512 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 513 fatal_fr(r, "sshbuf_set_max_size"); 514 c->ostate = CHAN_OUTPUT_OPEN; 515 c->istate = CHAN_INPUT_OPEN; 516 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 517 c->self = found; 518 c->type = type; 519 c->ctype = ctype; 520 c->local_window = window; 521 c->local_window_max = window; 522 c->local_maxpacket = maxpack; 523 c->remote_name = xstrdup(remote_name); 524 c->ctl_chan = -1; 525 c->delayed = 1; /* prevent call to channel_post handler */ 526 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 527 TAILQ_INIT(&c->status_confirms); 528 debug("channel %d: new %s [%s] (inactive timeout: %u)", 529 found, c->ctype, remote_name, c->inactive_deadline); 530 return c; 531 } 532 533 int 534 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 535 { 536 int ret, fd = *fdp; 537 538 if (fd == -1) 539 return 0; 540 541 /* restore blocking */ 542 if (*fdp == c->rfd && 543 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 544 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 545 else if (*fdp == c->wfd && 546 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 547 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 548 else if (*fdp == c->efd && 549 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 550 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 551 552 if (*fdp == c->rfd) { 553 c->io_want &= ~SSH_CHAN_IO_RFD; 554 c->io_ready &= ~SSH_CHAN_IO_RFD; 555 c->rfd = -1; 556 c->pfds[0] = -1; 557 } 558 if (*fdp == c->wfd) { 559 c->io_want &= ~SSH_CHAN_IO_WFD; 560 c->io_ready &= ~SSH_CHAN_IO_WFD; 561 c->wfd = -1; 562 c->pfds[1] = -1; 563 } 564 if (*fdp == c->efd) { 565 c->io_want &= ~SSH_CHAN_IO_EFD; 566 c->io_ready &= ~SSH_CHAN_IO_EFD; 567 c->efd = -1; 568 c->pfds[2] = -1; 569 } 570 if (*fdp == c->sock) { 571 c->io_want &= ~SSH_CHAN_IO_SOCK; 572 c->io_ready &= ~SSH_CHAN_IO_SOCK; 573 c->sock = -1; 574 c->pfds[3] = -1; 575 } 576 577 ret = close(fd); 578 *fdp = -1; /* probably redundant */ 579 return ret; 580 } 581 582 /* Close all channel fd/socket. */ 583 static void 584 channel_close_fds(struct ssh *ssh, Channel *c) 585 { 586 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 587 588 channel_close_fd(ssh, c, &c->sock); 589 if (rfd != sock) 590 channel_close_fd(ssh, c, &c->rfd); 591 if (wfd != sock && wfd != rfd) 592 channel_close_fd(ssh, c, &c->wfd); 593 if (efd != sock && efd != rfd && efd != wfd) 594 channel_close_fd(ssh, c, &c->efd); 595 } 596 597 static void 598 fwd_perm_clear(struct permission *perm) 599 { 600 free(perm->host_to_connect); 601 free(perm->listen_host); 602 free(perm->listen_path); 603 memset(perm, 0, sizeof(*perm)); 604 } 605 606 /* Returns an printable name for the specified forwarding permission list */ 607 static const char * 608 fwd_ident(int who, int where) 609 { 610 if (who == FORWARD_ADM) { 611 if (where == FORWARD_LOCAL) 612 return "admin local"; 613 else if (where == FORWARD_REMOTE) 614 return "admin remote"; 615 } else if (who == FORWARD_USER) { 616 if (where == FORWARD_LOCAL) 617 return "user local"; 618 else if (where == FORWARD_REMOTE) 619 return "user remote"; 620 } 621 fatal("Unknown forward permission list %d/%d", who, where); 622 } 623 624 /* Returns the forwarding permission list for the specified direction */ 625 static struct permission_set * 626 permission_set_get(struct ssh *ssh, int where) 627 { 628 struct ssh_channels *sc = ssh->chanctxt; 629 630 switch (where) { 631 case FORWARD_LOCAL: 632 return &sc->local_perms; 633 break; 634 case FORWARD_REMOTE: 635 return &sc->remote_perms; 636 break; 637 default: 638 fatal_f("invalid forwarding direction %d", where); 639 } 640 } 641 642 /* Returns pointers to the specified forwarding list and its element count */ 643 static void 644 permission_set_get_array(struct ssh *ssh, int who, int where, 645 struct permission ***permpp, u_int **npermpp) 646 { 647 struct permission_set *pset = permission_set_get(ssh, where); 648 649 switch (who) { 650 case FORWARD_USER: 651 *permpp = &pset->permitted_user; 652 *npermpp = &pset->num_permitted_user; 653 break; 654 case FORWARD_ADM: 655 *permpp = &pset->permitted_admin; 656 *npermpp = &pset->num_permitted_admin; 657 break; 658 default: 659 fatal_f("invalid forwarding client %d", who); 660 } 661 } 662 663 /* Adds an entry to the specified forwarding list */ 664 static int 665 permission_set_add(struct ssh *ssh, int who, int where, 666 const char *host_to_connect, int port_to_connect, 667 const char *listen_host, const char *listen_path, int listen_port, 668 Channel *downstream) 669 { 670 struct permission **permp; 671 u_int n, *npermp; 672 673 permission_set_get_array(ssh, who, where, &permp, &npermp); 674 675 if (*npermp >= INT_MAX) 676 fatal_f("%s overflow", fwd_ident(who, where)); 677 678 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 679 n = (*npermp)++; 680 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 681 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 682 (*permp)[n].port_to_connect = port_to_connect; 683 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 684 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 685 (*permp)[n].listen_port = listen_port; 686 (*permp)[n].downstream = downstream; 687 #undef MAYBE_DUP 688 return (int)n; 689 } 690 691 static void 692 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 693 { 694 struct ssh_channels *sc = ssh->chanctxt; 695 struct permission_set *pset = &sc->local_perms; 696 struct permission *perm; 697 int r; 698 u_int i; 699 700 for (i = 0; i < pset->num_permitted_user; i++) { 701 perm = &pset->permitted_user[i]; 702 if (perm->downstream != c) 703 continue; 704 705 /* cancel on the server, since mux client is gone */ 706 debug("channel %d: cleanup remote forward for %s:%u", 707 c->self, perm->listen_host, perm->listen_port); 708 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 709 (r = sshpkt_put_cstring(ssh, 710 "cancel-tcpip-forward")) != 0 || 711 (r = sshpkt_put_u8(ssh, 0)) != 0 || 712 (r = sshpkt_put_cstring(ssh, 713 channel_rfwd_bind_host(perm->listen_host))) != 0 || 714 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 715 (r = sshpkt_send(ssh)) != 0) { 716 fatal_fr(r, "channel %i", c->self); 717 } 718 fwd_perm_clear(perm); /* unregister */ 719 } 720 } 721 722 /* Free the channel and close its fd/socket. */ 723 void 724 channel_free(struct ssh *ssh, Channel *c) 725 { 726 struct ssh_channels *sc = ssh->chanctxt; 727 char *s; 728 u_int i, n; 729 Channel *other; 730 struct channel_confirm *cc; 731 732 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 733 if ((other = sc->channels[i]) == NULL) 734 continue; 735 n++; 736 /* detach from mux client and prepare for closing */ 737 if (c->type == SSH_CHANNEL_MUX_CLIENT && 738 other->type == SSH_CHANNEL_MUX_PROXY && 739 other->mux_ctx == c) { 740 other->mux_ctx = NULL; 741 other->type = SSH_CHANNEL_OPEN; 742 other->istate = CHAN_INPUT_CLOSED; 743 other->ostate = CHAN_OUTPUT_CLOSED; 744 } 745 } 746 debug("channel %d: free: %s, nchannels %u", c->self, 747 c->remote_name ? c->remote_name : "???", n); 748 749 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 750 mux_remove_remote_forwardings(ssh, c); 751 free(c->mux_ctx); 752 c->mux_ctx = NULL; 753 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 754 free(c->mux_ctx); 755 c->mux_ctx = NULL; 756 } 757 758 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 759 s = channel_open_message(ssh); 760 debug3("channel %d: status: %s", c->self, s); 761 free(s); 762 } 763 764 channel_close_fds(ssh, c); 765 sshbuf_free(c->input); 766 sshbuf_free(c->output); 767 sshbuf_free(c->extended); 768 c->input = c->output = c->extended = NULL; 769 free(c->remote_name); 770 c->remote_name = NULL; 771 free(c->path); 772 c->path = NULL; 773 free(c->listening_addr); 774 c->listening_addr = NULL; 775 free(c->xctype); 776 c->xctype = NULL; 777 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 778 if (cc->abandon_cb != NULL) 779 cc->abandon_cb(ssh, c, cc->ctx); 780 TAILQ_REMOVE(&c->status_confirms, cc, entry); 781 freezero(cc, sizeof(*cc)); 782 } 783 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 784 c->filter_cleanup(ssh, c->self, c->filter_ctx); 785 sc->channels[c->self] = NULL; 786 freezero(c, sizeof(*c)); 787 } 788 789 void 790 channel_free_all(struct ssh *ssh) 791 { 792 u_int i; 793 struct ssh_channels *sc = ssh->chanctxt; 794 795 for (i = 0; i < sc->channels_alloc; i++) 796 if (sc->channels[i] != NULL) 797 channel_free(ssh, sc->channels[i]); 798 799 free(sc->channels); 800 sc->channels = NULL; 801 sc->channels_alloc = 0; 802 803 free(sc->x11_saved_display); 804 sc->x11_saved_display = NULL; 805 806 free(sc->x11_saved_proto); 807 sc->x11_saved_proto = NULL; 808 809 free(sc->x11_saved_data); 810 sc->x11_saved_data = NULL; 811 sc->x11_saved_data_len = 0; 812 813 free(sc->x11_fake_data); 814 sc->x11_fake_data = NULL; 815 sc->x11_fake_data_len = 0; 816 } 817 818 /* 819 * Closes the sockets/fds of all channels. This is used to close extra file 820 * descriptors after a fork. 821 */ 822 void 823 channel_close_all(struct ssh *ssh) 824 { 825 u_int i; 826 827 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 828 if (ssh->chanctxt->channels[i] != NULL) 829 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 830 } 831 832 /* 833 * Stop listening to channels. 834 */ 835 void 836 channel_stop_listening(struct ssh *ssh) 837 { 838 u_int i; 839 Channel *c; 840 841 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 842 c = ssh->chanctxt->channels[i]; 843 if (c != NULL) { 844 switch (c->type) { 845 case SSH_CHANNEL_AUTH_SOCKET: 846 case SSH_CHANNEL_PORT_LISTENER: 847 case SSH_CHANNEL_RPORT_LISTENER: 848 case SSH_CHANNEL_X11_LISTENER: 849 case SSH_CHANNEL_UNIX_LISTENER: 850 case SSH_CHANNEL_RUNIX_LISTENER: 851 channel_close_fd(ssh, c, &c->sock); 852 channel_free(ssh, c); 853 break; 854 } 855 } 856 } 857 } 858 859 /* 860 * Returns true if no channel has too much buffered data, and false if one or 861 * more channel is overfull. 862 */ 863 int 864 channel_not_very_much_buffered_data(struct ssh *ssh) 865 { 866 u_int i; 867 u_int maxsize = ssh_packet_get_maxsize(ssh); 868 Channel *c; 869 870 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 871 c = ssh->chanctxt->channels[i]; 872 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 873 continue; 874 if (sshbuf_len(c->output) > maxsize) { 875 debug2("channel %d: big output buffer %zu > %u", 876 c->self, sshbuf_len(c->output), maxsize); 877 return 0; 878 } 879 } 880 return 1; 881 } 882 883 /* Returns true if any channel is still open. */ 884 int 885 channel_still_open(struct ssh *ssh) 886 { 887 u_int i; 888 Channel *c; 889 890 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 891 c = ssh->chanctxt->channels[i]; 892 if (c == NULL) 893 continue; 894 switch (c->type) { 895 case SSH_CHANNEL_X11_LISTENER: 896 case SSH_CHANNEL_PORT_LISTENER: 897 case SSH_CHANNEL_RPORT_LISTENER: 898 case SSH_CHANNEL_MUX_LISTENER: 899 case SSH_CHANNEL_CLOSED: 900 case SSH_CHANNEL_AUTH_SOCKET: 901 case SSH_CHANNEL_DYNAMIC: 902 case SSH_CHANNEL_RDYNAMIC_OPEN: 903 case SSH_CHANNEL_CONNECTING: 904 case SSH_CHANNEL_ZOMBIE: 905 case SSH_CHANNEL_ABANDONED: 906 case SSH_CHANNEL_UNIX_LISTENER: 907 case SSH_CHANNEL_RUNIX_LISTENER: 908 continue; 909 case SSH_CHANNEL_LARVAL: 910 continue; 911 case SSH_CHANNEL_OPENING: 912 case SSH_CHANNEL_OPEN: 913 case SSH_CHANNEL_RDYNAMIC_FINISH: 914 case SSH_CHANNEL_X11_OPEN: 915 case SSH_CHANNEL_MUX_CLIENT: 916 case SSH_CHANNEL_MUX_PROXY: 917 return 1; 918 default: 919 fatal_f("bad channel type %d", c->type); 920 /* NOTREACHED */ 921 } 922 } 923 return 0; 924 } 925 926 /* Returns true if a channel with a TTY is open. */ 927 int 928 channel_tty_open(struct ssh *ssh) 929 { 930 u_int i; 931 Channel *c; 932 933 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 934 c = ssh->chanctxt->channels[i]; 935 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 936 continue; 937 if (c->client_tty) 938 return 1; 939 } 940 return 0; 941 } 942 943 /* Returns the id of an open channel suitable for keepaliving */ 944 int 945 channel_find_open(struct ssh *ssh) 946 { 947 u_int i; 948 Channel *c; 949 950 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 951 c = ssh->chanctxt->channels[i]; 952 if (c == NULL || !c->have_remote_id) 953 continue; 954 switch (c->type) { 955 case SSH_CHANNEL_CLOSED: 956 case SSH_CHANNEL_DYNAMIC: 957 case SSH_CHANNEL_RDYNAMIC_OPEN: 958 case SSH_CHANNEL_RDYNAMIC_FINISH: 959 case SSH_CHANNEL_X11_LISTENER: 960 case SSH_CHANNEL_PORT_LISTENER: 961 case SSH_CHANNEL_RPORT_LISTENER: 962 case SSH_CHANNEL_MUX_LISTENER: 963 case SSH_CHANNEL_MUX_CLIENT: 964 case SSH_CHANNEL_MUX_PROXY: 965 case SSH_CHANNEL_OPENING: 966 case SSH_CHANNEL_CONNECTING: 967 case SSH_CHANNEL_ZOMBIE: 968 case SSH_CHANNEL_ABANDONED: 969 case SSH_CHANNEL_UNIX_LISTENER: 970 case SSH_CHANNEL_RUNIX_LISTENER: 971 continue; 972 case SSH_CHANNEL_LARVAL: 973 case SSH_CHANNEL_AUTH_SOCKET: 974 case SSH_CHANNEL_OPEN: 975 case SSH_CHANNEL_X11_OPEN: 976 return i; 977 default: 978 fatal_f("bad channel type %d", c->type); 979 /* NOTREACHED */ 980 } 981 } 982 return -1; 983 } 984 985 /* Returns the state of the channel's extended usage flag */ 986 const char * 987 channel_format_extended_usage(const Channel *c) 988 { 989 if (c->efd == -1) 990 return "closed"; 991 992 switch (c->extended_usage) { 993 case CHAN_EXTENDED_WRITE: 994 return "write"; 995 case CHAN_EXTENDED_READ: 996 return "read"; 997 case CHAN_EXTENDED_IGNORE: 998 return "ignore"; 999 default: 1000 return "UNKNOWN"; 1001 } 1002 } 1003 1004 static char * 1005 channel_format_status(const Channel *c) 1006 { 1007 char *ret = NULL; 1008 1009 xasprintf(&ret, "t%d [%s] %s%u %s%u i%u/%zu o%u/%zu e[%s]/%zu " 1010 "fd %d/%d/%d sock %d cc %d %s%u io 0x%02x/0x%02x", 1011 c->type, c->xctype != NULL ? c->xctype : c->ctype, 1012 c->have_remote_id ? "r" : "nr", c->remote_id, 1013 c->mux_ctx != NULL ? "m" : "nm", c->mux_downstream_id, 1014 c->istate, sshbuf_len(c->input), 1015 c->ostate, sshbuf_len(c->output), 1016 channel_format_extended_usage(c), sshbuf_len(c->extended), 1017 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 1018 c->have_ctl_child_id ? "c" : "nc", c->ctl_child_id, 1019 c->io_want, c->io_ready); 1020 return ret; 1021 } 1022 1023 /* 1024 * Returns a message describing the currently open forwarded connections, 1025 * suitable for sending to the client. The message contains crlf pairs for 1026 * newlines. 1027 */ 1028 char * 1029 channel_open_message(struct ssh *ssh) 1030 { 1031 struct sshbuf *buf; 1032 Channel *c; 1033 u_int i; 1034 int r; 1035 char *cp, *ret; 1036 1037 if ((buf = sshbuf_new()) == NULL) 1038 fatal_f("sshbuf_new"); 1039 if ((r = sshbuf_putf(buf, 1040 "The following connections are open:\r\n")) != 0) 1041 fatal_fr(r, "sshbuf_putf"); 1042 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1043 c = ssh->chanctxt->channels[i]; 1044 if (c == NULL) 1045 continue; 1046 switch (c->type) { 1047 case SSH_CHANNEL_X11_LISTENER: 1048 case SSH_CHANNEL_PORT_LISTENER: 1049 case SSH_CHANNEL_RPORT_LISTENER: 1050 case SSH_CHANNEL_CLOSED: 1051 case SSH_CHANNEL_AUTH_SOCKET: 1052 case SSH_CHANNEL_ZOMBIE: 1053 case SSH_CHANNEL_ABANDONED: 1054 case SSH_CHANNEL_MUX_LISTENER: 1055 case SSH_CHANNEL_UNIX_LISTENER: 1056 case SSH_CHANNEL_RUNIX_LISTENER: 1057 continue; 1058 case SSH_CHANNEL_LARVAL: 1059 case SSH_CHANNEL_OPENING: 1060 case SSH_CHANNEL_CONNECTING: 1061 case SSH_CHANNEL_DYNAMIC: 1062 case SSH_CHANNEL_RDYNAMIC_OPEN: 1063 case SSH_CHANNEL_RDYNAMIC_FINISH: 1064 case SSH_CHANNEL_OPEN: 1065 case SSH_CHANNEL_X11_OPEN: 1066 case SSH_CHANNEL_MUX_PROXY: 1067 case SSH_CHANNEL_MUX_CLIENT: 1068 cp = channel_format_status(c); 1069 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1070 c->self, c->remote_name, cp)) != 0) { 1071 free(cp); 1072 fatal_fr(r, "sshbuf_putf"); 1073 } 1074 free(cp); 1075 continue; 1076 default: 1077 fatal_f("bad channel type %d", c->type); 1078 /* NOTREACHED */ 1079 } 1080 } 1081 if ((ret = sshbuf_dup_string(buf)) == NULL) 1082 fatal_f("sshbuf_dup_string"); 1083 sshbuf_free(buf); 1084 return ret; 1085 } 1086 1087 static void 1088 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1089 { 1090 int r; 1091 1092 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1093 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1094 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1095 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1096 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1097 fatal_r(r, "%s: channel %i: open", where, c->self); 1098 } 1099 } 1100 1101 void 1102 channel_send_open(struct ssh *ssh, int id) 1103 { 1104 Channel *c = channel_lookup(ssh, id); 1105 int r; 1106 1107 if (c == NULL) { 1108 logit("channel_send_open: %d: bad id", id); 1109 return; 1110 } 1111 debug2("channel %d: send open", id); 1112 open_preamble(ssh, __func__, c, c->ctype); 1113 if ((r = sshpkt_send(ssh)) != 0) 1114 fatal_fr(r, "channel %i", c->self); 1115 } 1116 1117 void 1118 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 1119 { 1120 Channel *c = channel_lookup(ssh, id); 1121 int r; 1122 1123 if (c == NULL) { 1124 logit_f("%d: unknown channel id", id); 1125 return; 1126 } 1127 if (!c->have_remote_id) 1128 fatal_f("channel %d: no remote id", c->self); 1129 1130 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1131 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1132 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1133 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1134 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1135 fatal_fr(r, "channel %i", c->self); 1136 } 1137 } 1138 1139 void 1140 channel_register_status_confirm(struct ssh *ssh, int id, 1141 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1142 { 1143 struct channel_confirm *cc; 1144 Channel *c; 1145 1146 if ((c = channel_lookup(ssh, id)) == NULL) 1147 fatal_f("%d: bad id", id); 1148 1149 cc = xcalloc(1, sizeof(*cc)); 1150 cc->cb = cb; 1151 cc->abandon_cb = abandon_cb; 1152 cc->ctx = ctx; 1153 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1154 } 1155 1156 void 1157 channel_register_open_confirm(struct ssh *ssh, int id, 1158 channel_open_fn *fn, void *ctx) 1159 { 1160 Channel *c = channel_lookup(ssh, id); 1161 1162 if (c == NULL) { 1163 logit_f("%d: bad id", id); 1164 return; 1165 } 1166 c->open_confirm = fn; 1167 c->open_confirm_ctx = ctx; 1168 } 1169 1170 void 1171 channel_register_cleanup(struct ssh *ssh, int id, 1172 channel_callback_fn *fn, int do_close) 1173 { 1174 Channel *c = channel_by_id(ssh, id); 1175 1176 if (c == NULL) { 1177 logit_f("%d: bad id", id); 1178 return; 1179 } 1180 c->detach_user = fn; 1181 c->detach_close = do_close; 1182 } 1183 1184 void 1185 channel_cancel_cleanup(struct ssh *ssh, int id) 1186 { 1187 Channel *c = channel_by_id(ssh, id); 1188 1189 if (c == NULL) { 1190 logit_f("%d: bad id", id); 1191 return; 1192 } 1193 c->detach_user = NULL; 1194 c->detach_close = 0; 1195 } 1196 1197 void 1198 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1199 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1200 { 1201 Channel *c = channel_lookup(ssh, id); 1202 1203 if (c == NULL) { 1204 logit_f("%d: bad id", id); 1205 return; 1206 } 1207 c->input_filter = ifn; 1208 c->output_filter = ofn; 1209 c->filter_ctx = ctx; 1210 c->filter_cleanup = cfn; 1211 } 1212 1213 void 1214 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1215 int extusage, int nonblock, int is_tty, u_int window_max) 1216 { 1217 Channel *c = channel_lookup(ssh, id); 1218 int r; 1219 1220 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1221 fatal("channel_activate for non-larval channel %d.", id); 1222 if (!c->have_remote_id) 1223 fatal_f("channel %d: no remote id", c->self); 1224 1225 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1226 c->type = SSH_CHANNEL_OPEN; 1227 channel_set_used_time(ssh, c); 1228 c->local_window = c->local_window_max = window_max; 1229 1230 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1231 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1232 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1233 (r = sshpkt_send(ssh)) != 0) 1234 fatal_fr(r, "channel %i", c->self); 1235 } 1236 1237 static void 1238 channel_pre_listener(struct ssh *ssh, Channel *c) 1239 { 1240 c->io_want = SSH_CHAN_IO_SOCK_R; 1241 } 1242 1243 static void 1244 channel_pre_connecting(struct ssh *ssh, Channel *c) 1245 { 1246 debug3("channel %d: waiting for connection", c->self); 1247 c->io_want = SSH_CHAN_IO_SOCK_W; 1248 } 1249 1250 static void 1251 channel_pre_open(struct ssh *ssh, Channel *c) 1252 { 1253 c->io_want = 0; 1254 if (c->istate == CHAN_INPUT_OPEN && 1255 c->remote_window > 0 && 1256 sshbuf_len(c->input) < c->remote_window && 1257 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1258 c->io_want |= SSH_CHAN_IO_RFD; 1259 if (c->ostate == CHAN_OUTPUT_OPEN || 1260 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1261 if (sshbuf_len(c->output) > 0) { 1262 c->io_want |= SSH_CHAN_IO_WFD; 1263 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1264 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1265 debug2("channel %d: " 1266 "obuf_empty delayed efd %d/(%zu)", c->self, 1267 c->efd, sshbuf_len(c->extended)); 1268 else 1269 chan_obuf_empty(ssh, c); 1270 } 1271 } 1272 /** XXX check close conditions, too */ 1273 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1274 c->ostate == CHAN_OUTPUT_CLOSED)) { 1275 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1276 sshbuf_len(c->extended) > 0) 1277 c->io_want |= SSH_CHAN_IO_EFD_W; 1278 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1279 (c->extended_usage == CHAN_EXTENDED_READ || 1280 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1281 sshbuf_len(c->extended) < c->remote_window) 1282 c->io_want |= SSH_CHAN_IO_EFD_R; 1283 } 1284 /* XXX: What about efd? races? */ 1285 } 1286 1287 /* 1288 * This is a special state for X11 authentication spoofing. An opened X11 1289 * connection (when authentication spoofing is being done) remains in this 1290 * state until the first packet has been completely read. The authentication 1291 * data in that packet is then substituted by the real data if it matches the 1292 * fake data, and the channel is put into normal mode. 1293 * XXX All this happens at the client side. 1294 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1295 */ 1296 static int 1297 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1298 { 1299 struct ssh_channels *sc = ssh->chanctxt; 1300 u_char *ucp; 1301 u_int proto_len, data_len; 1302 1303 /* Is this being called after the refusal deadline? */ 1304 if (sc->x11_refuse_time != 0 && 1305 monotime() >= sc->x11_refuse_time) { 1306 verbose("Rejected X11 connection after ForwardX11Timeout " 1307 "expired"); 1308 return -1; 1309 } 1310 1311 /* Check if the fixed size part of the packet is in buffer. */ 1312 if (sshbuf_len(b) < 12) 1313 return 0; 1314 1315 /* Parse the lengths of variable-length fields. */ 1316 ucp = sshbuf_mutable_ptr(b); 1317 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1318 proto_len = 256 * ucp[6] + ucp[7]; 1319 data_len = 256 * ucp[8] + ucp[9]; 1320 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1321 proto_len = ucp[6] + 256 * ucp[7]; 1322 data_len = ucp[8] + 256 * ucp[9]; 1323 } else { 1324 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1325 ucp[0]); 1326 return -1; 1327 } 1328 1329 /* Check if the whole packet is in buffer. */ 1330 if (sshbuf_len(b) < 1331 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1332 return 0; 1333 1334 /* Check if authentication protocol matches. */ 1335 if (proto_len != strlen(sc->x11_saved_proto) || 1336 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1337 debug2("X11 connection uses different authentication protocol."); 1338 return -1; 1339 } 1340 /* Check if authentication data matches our fake data. */ 1341 if (data_len != sc->x11_fake_data_len || 1342 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1343 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1344 debug2("X11 auth data does not match fake data."); 1345 return -1; 1346 } 1347 /* Check fake data length */ 1348 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1349 error("X11 fake_data_len %d != saved_data_len %d", 1350 sc->x11_fake_data_len, sc->x11_saved_data_len); 1351 return -1; 1352 } 1353 /* 1354 * Received authentication protocol and data match 1355 * our fake data. Substitute the fake data with real 1356 * data. 1357 */ 1358 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1359 sc->x11_saved_data, sc->x11_saved_data_len); 1360 return 1; 1361 } 1362 1363 void 1364 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1365 { 1366 debug3_f("channel %d: forcibly closing", c->self); 1367 if (c->istate == CHAN_INPUT_OPEN) 1368 chan_read_failed(ssh, c); 1369 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1370 sshbuf_reset(c->input); 1371 chan_ibuf_empty(ssh, c); 1372 } 1373 if (c->ostate == CHAN_OUTPUT_OPEN || 1374 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1375 sshbuf_reset(c->output); 1376 chan_write_failed(ssh, c); 1377 } 1378 if (c->detach_user) 1379 c->detach_user(ssh, c->self, 1, NULL); 1380 if (c->efd != -1) 1381 channel_close_fd(ssh, c, &c->efd); 1382 if (abandon) 1383 c->type = SSH_CHANNEL_ABANDONED; 1384 /* exempt from inactivity timeouts */ 1385 c->inactive_deadline = 0; 1386 c->lastused = 0; 1387 } 1388 1389 static void 1390 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1391 { 1392 int ret = x11_open_helper(ssh, c->output); 1393 1394 /* c->force_drain = 1; */ 1395 1396 if (ret == 1) { 1397 c->type = SSH_CHANNEL_OPEN; 1398 channel_set_used_time(ssh, c); 1399 channel_pre_open(ssh, c); 1400 } else if (ret == -1) { 1401 logit("X11 connection rejected because of wrong " 1402 "authentication."); 1403 debug2("X11 rejected %d i%d/o%d", 1404 c->self, c->istate, c->ostate); 1405 channel_force_close(ssh, c, 0); 1406 } 1407 } 1408 1409 static void 1410 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1411 { 1412 c->io_want = 0; 1413 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1414 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1415 c->io_want |= SSH_CHAN_IO_RFD; 1416 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1417 /* clear buffer immediately (discard any partial packet) */ 1418 sshbuf_reset(c->input); 1419 chan_ibuf_empty(ssh, c); 1420 /* Start output drain. XXX just kill chan? */ 1421 chan_rcvd_oclose(ssh, c); 1422 } 1423 if (c->ostate == CHAN_OUTPUT_OPEN || 1424 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1425 if (sshbuf_len(c->output) > 0) 1426 c->io_want |= SSH_CHAN_IO_WFD; 1427 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1428 chan_obuf_empty(ssh, c); 1429 } 1430 } 1431 1432 /* try to decode a socks4 header */ 1433 static int 1434 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1435 { 1436 const u_char *p; 1437 char *host; 1438 u_int len, have, i, found, need; 1439 char username[256]; 1440 struct { 1441 u_int8_t version; 1442 u_int8_t command; 1443 u_int16_t dest_port; 1444 struct in_addr dest_addr; 1445 } s4_req, s4_rsp; 1446 int r; 1447 1448 debug2("channel %d: decode socks4", c->self); 1449 1450 have = sshbuf_len(input); 1451 len = sizeof(s4_req); 1452 if (have < len) 1453 return 0; 1454 p = sshbuf_ptr(input); 1455 1456 need = 1; 1457 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1458 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1459 debug2("channel %d: socks4a request", c->self); 1460 /* ... and needs an extra string (the hostname) */ 1461 need = 2; 1462 } 1463 /* Check for terminating NUL on the string(s) */ 1464 for (found = 0, i = len; i < have; i++) { 1465 if (p[i] == '\0') { 1466 found++; 1467 if (found == need) 1468 break; 1469 } 1470 if (i > 1024) { 1471 /* the peer is probably sending garbage */ 1472 debug("channel %d: decode socks4: too long", 1473 c->self); 1474 return -1; 1475 } 1476 } 1477 if (found < need) 1478 return 0; 1479 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1480 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1481 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1482 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1483 debug_r(r, "channels %d: decode socks4", c->self); 1484 return -1; 1485 } 1486 have = sshbuf_len(input); 1487 p = sshbuf_ptr(input); 1488 if (memchr(p, '\0', have) == NULL) { 1489 error("channel %d: decode socks4: unterminated user", c->self); 1490 return -1; 1491 } 1492 len = strlen(p); 1493 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1494 len++; /* trailing '\0' */ 1495 strlcpy(username, p, sizeof(username)); 1496 if ((r = sshbuf_consume(input, len)) != 0) 1497 fatal_fr(r, "channel %d: consume", c->self); 1498 free(c->path); 1499 c->path = NULL; 1500 if (need == 1) { /* SOCKS4: one string */ 1501 host = inet_ntoa(s4_req.dest_addr); 1502 c->path = xstrdup(host); 1503 } else { /* SOCKS4A: two strings */ 1504 have = sshbuf_len(input); 1505 p = sshbuf_ptr(input); 1506 if (memchr(p, '\0', have) == NULL) { 1507 error("channel %d: decode socks4a: host not nul " 1508 "terminated", c->self); 1509 return -1; 1510 } 1511 len = strlen(p); 1512 debug2("channel %d: decode socks4a: host %s/%d", 1513 c->self, p, len); 1514 len++; /* trailing '\0' */ 1515 if (len > NI_MAXHOST) { 1516 error("channel %d: hostname \"%.100s\" too long", 1517 c->self, p); 1518 return -1; 1519 } 1520 c->path = xstrdup(p); 1521 if ((r = sshbuf_consume(input, len)) != 0) 1522 fatal_fr(r, "channel %d: consume", c->self); 1523 } 1524 c->host_port = ntohs(s4_req.dest_port); 1525 1526 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1527 c->self, c->path, c->host_port, s4_req.command); 1528 1529 if (s4_req.command != 1) { 1530 debug("channel %d: cannot handle: %s cn %d", 1531 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1532 return -1; 1533 } 1534 s4_rsp.version = 0; /* vn: 0 for reply */ 1535 s4_rsp.command = 90; /* cd: req granted */ 1536 s4_rsp.dest_port = 0; /* ignored */ 1537 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1538 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1539 fatal_fr(r, "channel %d: append reply", c->self); 1540 return 1; 1541 } 1542 1543 /* try to decode a socks5 header */ 1544 #define SSH_SOCKS5_AUTHDONE 0x1000 1545 #define SSH_SOCKS5_NOAUTH 0x00 1546 #define SSH_SOCKS5_IPV4 0x01 1547 #define SSH_SOCKS5_DOMAIN 0x03 1548 #define SSH_SOCKS5_IPV6 0x04 1549 #define SSH_SOCKS5_CONNECT 0x01 1550 #define SSH_SOCKS5_SUCCESS 0x00 1551 1552 static int 1553 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1554 { 1555 /* XXX use get/put_u8 instead of trusting struct padding */ 1556 struct { 1557 u_int8_t version; 1558 u_int8_t command; 1559 u_int8_t reserved; 1560 u_int8_t atyp; 1561 } s5_req, s5_rsp; 1562 u_int16_t dest_port; 1563 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1564 const u_char *p; 1565 u_int have, need, i, found, nmethods, addrlen, af; 1566 int r; 1567 1568 debug2("channel %d: decode socks5", c->self); 1569 p = sshbuf_ptr(input); 1570 if (p[0] != 0x05) 1571 return -1; 1572 have = sshbuf_len(input); 1573 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1574 /* format: ver | nmethods | methods */ 1575 if (have < 2) 1576 return 0; 1577 nmethods = p[1]; 1578 if (have < nmethods + 2) 1579 return 0; 1580 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1581 for (found = 0, i = 2; i < nmethods + 2; i++) { 1582 if (p[i] == SSH_SOCKS5_NOAUTH) { 1583 found = 1; 1584 break; 1585 } 1586 } 1587 if (!found) { 1588 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1589 c->self); 1590 return -1; 1591 } 1592 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1593 fatal_fr(r, "channel %d: consume", c->self); 1594 /* version, method */ 1595 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1596 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1597 fatal_fr(r, "channel %d: append reply", c->self); 1598 c->flags |= SSH_SOCKS5_AUTHDONE; 1599 debug2("channel %d: socks5 auth done", c->self); 1600 return 0; /* need more */ 1601 } 1602 debug2("channel %d: socks5 post auth", c->self); 1603 if (have < sizeof(s5_req)+1) 1604 return 0; /* need more */ 1605 memcpy(&s5_req, p, sizeof(s5_req)); 1606 if (s5_req.version != 0x05 || 1607 s5_req.command != SSH_SOCKS5_CONNECT || 1608 s5_req.reserved != 0x00) { 1609 debug2("channel %d: only socks5 connect supported", c->self); 1610 return -1; 1611 } 1612 switch (s5_req.atyp){ 1613 case SSH_SOCKS5_IPV4: 1614 addrlen = 4; 1615 af = AF_INET; 1616 break; 1617 case SSH_SOCKS5_DOMAIN: 1618 addrlen = p[sizeof(s5_req)]; 1619 af = -1; 1620 break; 1621 case SSH_SOCKS5_IPV6: 1622 addrlen = 16; 1623 af = AF_INET6; 1624 break; 1625 default: 1626 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1627 return -1; 1628 } 1629 need = sizeof(s5_req) + addrlen + 2; 1630 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1631 need++; 1632 if (have < need) 1633 return 0; 1634 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1635 fatal_fr(r, "channel %d: consume", c->self); 1636 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1637 /* host string length */ 1638 if ((r = sshbuf_consume(input, 1)) != 0) 1639 fatal_fr(r, "channel %d: consume", c->self); 1640 } 1641 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1642 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1643 debug_r(r, "channel %d: parse addr/port", c->self); 1644 return -1; 1645 } 1646 dest_addr[addrlen] = '\0'; 1647 free(c->path); 1648 c->path = NULL; 1649 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1650 if (addrlen >= NI_MAXHOST) { 1651 error("channel %d: dynamic request: socks5 hostname " 1652 "\"%.100s\" too long", c->self, dest_addr); 1653 return -1; 1654 } 1655 c->path = xstrdup(dest_addr); 1656 } else { 1657 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1658 return -1; 1659 c->path = xstrdup(ntop); 1660 } 1661 c->host_port = ntohs(dest_port); 1662 1663 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1664 c->self, c->path, c->host_port, s5_req.command); 1665 1666 s5_rsp.version = 0x05; 1667 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1668 s5_rsp.reserved = 0; /* ignored */ 1669 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1670 dest_port = 0; /* ignored */ 1671 1672 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1673 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1674 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1675 fatal_fr(r, "channel %d: append reply", c->self); 1676 return 1; 1677 } 1678 1679 Channel * 1680 channel_connect_stdio_fwd(struct ssh *ssh, 1681 const char *host_to_connect, int port_to_connect, 1682 int in, int out, int nonblock) 1683 { 1684 Channel *c; 1685 1686 debug_f("%s:%d", host_to_connect, port_to_connect); 1687 1688 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1689 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1690 0, "stdio-forward", nonblock); 1691 1692 c->path = xstrdup(host_to_connect); 1693 c->host_port = port_to_connect; 1694 c->listening_port = 0; 1695 c->force_drain = 1; 1696 1697 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1698 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1699 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1700 1701 return c; 1702 } 1703 1704 /* dynamic port forwarding */ 1705 static void 1706 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1707 { 1708 const u_char *p; 1709 u_int have; 1710 int ret; 1711 1712 c->io_want = 0; 1713 have = sshbuf_len(c->input); 1714 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1715 /* sshbuf_dump(c->input, stderr); */ 1716 /* check if the fixed size part of the packet is in buffer. */ 1717 if (have < 3) { 1718 /* need more */ 1719 c->io_want |= SSH_CHAN_IO_RFD; 1720 return; 1721 } 1722 /* try to guess the protocol */ 1723 p = sshbuf_ptr(c->input); 1724 /* XXX sshbuf_peek_u8? */ 1725 switch (p[0]) { 1726 case 0x04: 1727 ret = channel_decode_socks4(c, c->input, c->output); 1728 break; 1729 case 0x05: 1730 ret = channel_decode_socks5(c, c->input, c->output); 1731 break; 1732 default: 1733 ret = -1; 1734 break; 1735 } 1736 if (ret < 0) { 1737 chan_mark_dead(ssh, c); 1738 } else if (ret == 0) { 1739 debug2("channel %d: pre_dynamic: need more", c->self); 1740 /* need more */ 1741 c->io_want |= SSH_CHAN_IO_RFD; 1742 if (sshbuf_len(c->output)) 1743 c->io_want |= SSH_CHAN_IO_WFD; 1744 } else { 1745 /* switch to the next state */ 1746 c->type = SSH_CHANNEL_OPENING; 1747 port_open_helper(ssh, c, "direct-tcpip"); 1748 } 1749 } 1750 1751 /* simulate read-error */ 1752 static void 1753 rdynamic_close(struct ssh *ssh, Channel *c) 1754 { 1755 c->type = SSH_CHANNEL_OPEN; 1756 channel_force_close(ssh, c, 0); 1757 } 1758 1759 /* reverse dynamic port forwarding */ 1760 static void 1761 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1762 { 1763 const u_char *p; 1764 u_int have, len; 1765 int r, ret; 1766 1767 have = sshbuf_len(c->output); 1768 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1769 /* sshbuf_dump(c->output, stderr); */ 1770 /* EOF received */ 1771 if (c->flags & CHAN_EOF_RCVD) { 1772 if ((r = sshbuf_consume(c->output, have)) != 0) 1773 fatal_fr(r, "channel %d: consume", c->self); 1774 rdynamic_close(ssh, c); 1775 return; 1776 } 1777 /* check if the fixed size part of the packet is in buffer. */ 1778 if (have < 3) 1779 return; 1780 /* try to guess the protocol */ 1781 p = sshbuf_ptr(c->output); 1782 switch (p[0]) { 1783 case 0x04: 1784 /* switch input/output for reverse forwarding */ 1785 ret = channel_decode_socks4(c, c->output, c->input); 1786 break; 1787 case 0x05: 1788 ret = channel_decode_socks5(c, c->output, c->input); 1789 break; 1790 default: 1791 ret = -1; 1792 break; 1793 } 1794 if (ret < 0) { 1795 rdynamic_close(ssh, c); 1796 } else if (ret == 0) { 1797 debug2("channel %d: pre_rdynamic: need more", c->self); 1798 /* send socks request to peer */ 1799 len = sshbuf_len(c->input); 1800 if (len > 0 && len < c->remote_window) { 1801 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1802 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1803 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1804 (r = sshpkt_send(ssh)) != 0) { 1805 fatal_fr(r, "channel %i: rdynamic", c->self); 1806 } 1807 if ((r = sshbuf_consume(c->input, len)) != 0) 1808 fatal_fr(r, "channel %d: consume", c->self); 1809 c->remote_window -= len; 1810 } 1811 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1812 /* the connect failed */ 1813 rdynamic_close(ssh, c); 1814 } 1815 } 1816 1817 /* This is our fake X11 server socket. */ 1818 static void 1819 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1820 { 1821 Channel *nc; 1822 struct sockaddr_storage addr; 1823 int r, newsock, oerrno, remote_port; 1824 socklen_t addrlen; 1825 char buf[16384], *remote_ipaddr; 1826 1827 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1828 return; 1829 1830 debug("X11 connection requested."); 1831 addrlen = sizeof(addr); 1832 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1833 if (c->single_connection) { 1834 oerrno = errno; 1835 debug2("single_connection: closing X11 listener."); 1836 channel_close_fd(ssh, c, &c->sock); 1837 chan_mark_dead(ssh, c); 1838 errno = oerrno; 1839 } 1840 if (newsock == -1) { 1841 if (errno != EINTR && errno != EWOULDBLOCK && 1842 errno != ECONNABORTED) 1843 error("accept: %.100s", strerror(errno)); 1844 if (errno == EMFILE || errno == ENFILE) 1845 c->notbefore = monotime() + 1; 1846 return; 1847 } 1848 set_nodelay(newsock); 1849 remote_ipaddr = get_peer_ipaddr(newsock); 1850 remote_port = get_peer_port(newsock); 1851 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1852 remote_ipaddr, remote_port); 1853 1854 nc = channel_new(ssh, "x11-connection", 1855 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1856 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1857 open_preamble(ssh, __func__, nc, "x11"); 1858 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1859 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1860 fatal_fr(r, "channel %i: reply", c->self); 1861 } 1862 if ((r = sshpkt_send(ssh)) != 0) 1863 fatal_fr(r, "channel %i: send", c->self); 1864 free(remote_ipaddr); 1865 } 1866 1867 static void 1868 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1869 { 1870 char *local_ipaddr = get_local_ipaddr(c->sock); 1871 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1872 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1873 int remote_port = get_peer_port(c->sock); 1874 int r; 1875 1876 if (remote_port == -1) { 1877 /* Fake addr/port to appease peers that validate it (Tectia) */ 1878 free(remote_ipaddr); 1879 remote_ipaddr = xstrdup("127.0.0.1"); 1880 remote_port = 65535; 1881 } 1882 1883 free(c->remote_name); 1884 xasprintf(&c->remote_name, 1885 "%s: listening port %d for %.100s port %d, " 1886 "connect from %.200s port %d to %.100s port %d", 1887 rtype, c->listening_port, c->path, c->host_port, 1888 remote_ipaddr, remote_port, local_ipaddr, local_port); 1889 1890 open_preamble(ssh, __func__, c, rtype); 1891 if (strcmp(rtype, "direct-tcpip") == 0) { 1892 /* target host, port */ 1893 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1894 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1895 fatal_fr(r, "channel %i: reply", c->self); 1896 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1897 /* target path */ 1898 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1899 fatal_fr(r, "channel %i: reply", c->self); 1900 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1901 /* listen path */ 1902 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1903 fatal_fr(r, "channel %i: reply", c->self); 1904 } else { 1905 /* listen address, port */ 1906 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1907 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1908 fatal_fr(r, "channel %i: reply", c->self); 1909 } 1910 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1911 /* reserved for future owner/mode info */ 1912 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1913 fatal_fr(r, "channel %i: reply", c->self); 1914 } else { 1915 /* originator host and port */ 1916 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1917 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1918 fatal_fr(r, "channel %i: reply", c->self); 1919 } 1920 if ((r = sshpkt_send(ssh)) != 0) 1921 fatal_fr(r, "channel %i: send", c->self); 1922 free(remote_ipaddr); 1923 free(local_ipaddr); 1924 } 1925 1926 void 1927 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1928 { 1929 ssh->chanctxt->x11_refuse_time = refuse_time; 1930 } 1931 1932 /* 1933 * This socket is listening for connections to a forwarded TCP/IP port. 1934 */ 1935 static void 1936 channel_post_port_listener(struct ssh *ssh, Channel *c) 1937 { 1938 Channel *nc; 1939 struct sockaddr_storage addr; 1940 int newsock, nextstate; 1941 socklen_t addrlen; 1942 char *rtype; 1943 1944 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1945 return; 1946 1947 debug("Connection to port %d forwarding to %.100s port %d requested.", 1948 c->listening_port, c->path, c->host_port); 1949 1950 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1951 nextstate = SSH_CHANNEL_OPENING; 1952 rtype = "forwarded-tcpip"; 1953 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1954 nextstate = SSH_CHANNEL_OPENING; 1955 rtype = "forwarded-streamlocal@openssh.com"; 1956 } else if (c->host_port == PORT_STREAMLOCAL) { 1957 nextstate = SSH_CHANNEL_OPENING; 1958 rtype = "direct-streamlocal@openssh.com"; 1959 } else if (c->host_port == 0) { 1960 nextstate = SSH_CHANNEL_DYNAMIC; 1961 rtype = "dynamic-tcpip"; 1962 } else { 1963 nextstate = SSH_CHANNEL_OPENING; 1964 rtype = "direct-tcpip"; 1965 } 1966 1967 addrlen = sizeof(addr); 1968 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1969 if (newsock == -1) { 1970 if (errno != EINTR && errno != EWOULDBLOCK && 1971 errno != ECONNABORTED) 1972 error("accept: %.100s", strerror(errno)); 1973 if (errno == EMFILE || errno == ENFILE) 1974 c->notbefore = monotime() + 1; 1975 return; 1976 } 1977 if (c->host_port != PORT_STREAMLOCAL) 1978 set_nodelay(newsock); 1979 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1980 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1981 nc->listening_port = c->listening_port; 1982 nc->host_port = c->host_port; 1983 if (c->path != NULL) 1984 nc->path = xstrdup(c->path); 1985 1986 if (nextstate != SSH_CHANNEL_DYNAMIC) 1987 port_open_helper(ssh, nc, rtype); 1988 } 1989 1990 /* 1991 * This is the authentication agent socket listening for connections from 1992 * clients. 1993 */ 1994 static void 1995 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1996 { 1997 Channel *nc; 1998 int r, newsock; 1999 struct sockaddr_storage addr; 2000 socklen_t addrlen; 2001 2002 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2003 return; 2004 2005 addrlen = sizeof(addr); 2006 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2007 if (newsock == -1) { 2008 error("accept from auth socket: %.100s", strerror(errno)); 2009 if (errno == EMFILE || errno == ENFILE) 2010 c->notbefore = monotime() + 1; 2011 return; 2012 } 2013 nc = channel_new(ssh, "agent-connection", 2014 SSH_CHANNEL_OPENING, newsock, newsock, -1, 2015 c->local_window_max, c->local_maxpacket, 2016 0, "accepted auth socket", 1); 2017 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 2018 if ((r = sshpkt_send(ssh)) != 0) 2019 fatal_fr(r, "channel %i", c->self); 2020 } 2021 2022 static void 2023 channel_post_connecting(struct ssh *ssh, Channel *c) 2024 { 2025 int err = 0, sock, isopen, r; 2026 socklen_t sz = sizeof(err); 2027 2028 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2029 return; 2030 if (!c->have_remote_id) 2031 fatal_f("channel %d: no remote id", c->self); 2032 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2033 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2034 2035 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2036 err = errno; 2037 error("getsockopt SO_ERROR failed"); 2038 } 2039 2040 if (err == 0) { 2041 /* Non-blocking connection completed */ 2042 debug("channel %d: connected to %s port %d", 2043 c->self, c->connect_ctx.host, c->connect_ctx.port); 2044 channel_connect_ctx_free(&c->connect_ctx); 2045 c->type = SSH_CHANNEL_OPEN; 2046 channel_set_used_time(ssh, c); 2047 if (isopen) { 2048 /* no message necessary */ 2049 } else { 2050 if ((r = sshpkt_start(ssh, 2051 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2052 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2053 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2054 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2055 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2056 (r = sshpkt_send(ssh)) != 0) 2057 fatal_fr(r, "channel %i open confirm", c->self); 2058 } 2059 return; 2060 } 2061 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2062 return; 2063 2064 /* Non-blocking connection failed */ 2065 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2066 2067 /* Try next address, if any */ 2068 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2069 /* Exhausted all addresses for this destination */ 2070 error("connect_to %.100s port %d: failed.", 2071 c->connect_ctx.host, c->connect_ctx.port); 2072 channel_connect_ctx_free(&c->connect_ctx); 2073 if (isopen) { 2074 rdynamic_close(ssh, c); 2075 } else { 2076 if ((r = sshpkt_start(ssh, 2077 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2078 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2079 (r = sshpkt_put_u32(ssh, 2080 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2081 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2082 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2083 (r = sshpkt_send(ssh)) != 0) 2084 fatal_fr(r, "channel %i: failure", c->self); 2085 chan_mark_dead(ssh, c); 2086 } 2087 } 2088 2089 /* New non-blocking connection in progress */ 2090 close(c->sock); 2091 c->sock = c->rfd = c->wfd = sock; 2092 } 2093 2094 static int 2095 channel_handle_rfd(struct ssh *ssh, Channel *c) 2096 { 2097 char buf[CHAN_RBUF]; 2098 ssize_t len; 2099 int r; 2100 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2101 2102 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2103 return 1; /* Shouldn't happen */ 2104 if ((avail = sshbuf_avail(c->input)) == 0) 2105 return 1; /* Shouldn't happen */ 2106 2107 /* 2108 * For "simple" channels (i.e. not datagram or filtered), we can 2109 * read directly to the channel buffer. 2110 */ 2111 if (c->input_filter == NULL && !c->datagram) { 2112 /* Only OPEN channels have valid rwin */ 2113 if (c->type == SSH_CHANNEL_OPEN) { 2114 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2115 return 1; /* shouldn't happen */ 2116 if (maxlen > c->remote_window - have) 2117 maxlen = c->remote_window - have; 2118 } 2119 if (maxlen > avail) 2120 maxlen = avail; 2121 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2122 if (errno == EINTR || errno == EAGAIN) 2123 return 1; 2124 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2125 c->self, c->rfd, maxlen, ssh_err(r)); 2126 goto rfail; 2127 } 2128 if (nr != 0) 2129 channel_set_used_time(ssh, c); 2130 return 1; 2131 } 2132 2133 len = read(c->rfd, buf, sizeof(buf)); 2134 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2135 return 1; 2136 if (len <= 0) { 2137 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2138 c->self, c->rfd, len, 2139 len == 0 ? "closed" : strerror(errno)); 2140 rfail: 2141 if (c->type != SSH_CHANNEL_OPEN) { 2142 debug2("channel %d: not open", c->self); 2143 chan_mark_dead(ssh, c); 2144 return -1; 2145 } else { 2146 chan_read_failed(ssh, c); 2147 } 2148 return -1; 2149 } 2150 channel_set_used_time(ssh, c); 2151 if (c->input_filter != NULL) { 2152 if (c->input_filter(ssh, c, buf, len) == -1) { 2153 debug2("channel %d: filter stops", c->self); 2154 chan_read_failed(ssh, c); 2155 } 2156 } else if (c->datagram) { 2157 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2158 fatal_fr(r, "channel %i: put datagram", c->self); 2159 } 2160 return 1; 2161 } 2162 2163 static int 2164 channel_handle_wfd(struct ssh *ssh, Channel *c) 2165 { 2166 struct termios tio; 2167 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2168 size_t dlen, olen = 0; 2169 int r, len; 2170 2171 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2172 return 1; 2173 if (sshbuf_len(c->output) == 0) 2174 return 1; 2175 2176 /* Send buffered output data to the socket. */ 2177 olen = sshbuf_len(c->output); 2178 if (c->output_filter != NULL) { 2179 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2180 debug2("channel %d: filter stops", c->self); 2181 if (c->type != SSH_CHANNEL_OPEN) 2182 chan_mark_dead(ssh, c); 2183 else 2184 chan_write_failed(ssh, c); 2185 return -1; 2186 } 2187 } else if (c->datagram) { 2188 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2189 fatal_fr(r, "channel %i: get datagram", c->self); 2190 buf = data; 2191 } else { 2192 buf = data = sshbuf_mutable_ptr(c->output); 2193 dlen = sshbuf_len(c->output); 2194 } 2195 2196 if (c->datagram) { 2197 /* ignore truncated writes, datagrams might get lost */ 2198 len = write(c->wfd, buf, dlen); 2199 free(data); 2200 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2201 return 1; 2202 if (len <= 0) 2203 goto write_fail; 2204 goto out; 2205 } 2206 2207 len = write(c->wfd, buf, dlen); 2208 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2209 return 1; 2210 if (len <= 0) { 2211 write_fail: 2212 if (c->type != SSH_CHANNEL_OPEN) { 2213 debug2("channel %d: not open", c->self); 2214 chan_mark_dead(ssh, c); 2215 return -1; 2216 } else { 2217 chan_write_failed(ssh, c); 2218 } 2219 return -1; 2220 } 2221 channel_set_used_time(ssh, c); 2222 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2223 if (tcgetattr(c->wfd, &tio) == 0 && 2224 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2225 /* 2226 * Simulate echo to reduce the impact of 2227 * traffic analysis. We need to match the 2228 * size of a SSH2_MSG_CHANNEL_DATA message 2229 * (4 byte channel id + buf) 2230 */ 2231 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2232 (r = sshpkt_send(ssh)) != 0) 2233 fatal_fr(r, "channel %i: ignore", c->self); 2234 } 2235 } 2236 if ((r = sshbuf_consume(c->output, len)) != 0) 2237 fatal_fr(r, "channel %i: consume", c->self); 2238 out: 2239 c->local_consumed += olen - sshbuf_len(c->output); 2240 2241 return 1; 2242 } 2243 2244 static int 2245 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2246 { 2247 int r; 2248 ssize_t len; 2249 2250 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2251 return 1; 2252 if (sshbuf_len(c->extended) == 0) 2253 return 1; 2254 2255 len = write(c->efd, sshbuf_ptr(c->extended), 2256 sshbuf_len(c->extended)); 2257 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2258 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2259 return 1; 2260 if (len <= 0) { 2261 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2262 channel_close_fd(ssh, c, &c->efd); 2263 } else { 2264 if ((r = sshbuf_consume(c->extended, len)) != 0) 2265 fatal_fr(r, "channel %i: consume", c->self); 2266 c->local_consumed += len; 2267 channel_set_used_time(ssh, c); 2268 } 2269 return 1; 2270 } 2271 2272 static int 2273 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2274 { 2275 char buf[CHAN_RBUF]; 2276 int r; 2277 ssize_t len; 2278 2279 if ((c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2280 return 1; 2281 2282 len = read(c->efd, buf, sizeof(buf)); 2283 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2284 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2285 return 1; 2286 if (len <= 0) { 2287 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2288 channel_close_fd(ssh, c, &c->efd); 2289 return 1; 2290 } 2291 channel_set_used_time(ssh, c); 2292 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2293 debug3("channel %d: discard efd", c->self); 2294 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2295 fatal_fr(r, "channel %i: append", c->self); 2296 return 1; 2297 } 2298 2299 static int 2300 channel_handle_efd(struct ssh *ssh, Channel *c) 2301 { 2302 if (c->efd == -1) 2303 return 1; 2304 2305 /** XXX handle drain efd, too */ 2306 2307 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2308 return channel_handle_efd_write(ssh, c); 2309 else if (c->extended_usage == CHAN_EXTENDED_READ || 2310 c->extended_usage == CHAN_EXTENDED_IGNORE) 2311 return channel_handle_efd_read(ssh, c); 2312 2313 return 1; 2314 } 2315 2316 static int 2317 channel_check_window(struct ssh *ssh, Channel *c) 2318 { 2319 int r; 2320 2321 if (c->type == SSH_CHANNEL_OPEN && 2322 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2323 ((c->local_window_max - c->local_window > 2324 c->local_maxpacket*3) || 2325 c->local_window < c->local_window_max/2) && 2326 c->local_consumed > 0) { 2327 if (!c->have_remote_id) 2328 fatal_f("channel %d: no remote id", c->self); 2329 if ((r = sshpkt_start(ssh, 2330 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2331 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2332 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2333 (r = sshpkt_send(ssh)) != 0) { 2334 fatal_fr(r, "channel %i", c->self); 2335 } 2336 debug2("channel %d: window %d sent adjust %d", c->self, 2337 c->local_window, c->local_consumed); 2338 c->local_window += c->local_consumed; 2339 c->local_consumed = 0; 2340 } 2341 return 1; 2342 } 2343 2344 static void 2345 channel_post_open(struct ssh *ssh, Channel *c) 2346 { 2347 channel_handle_rfd(ssh, c); 2348 channel_handle_wfd(ssh, c); 2349 channel_handle_efd(ssh, c); 2350 channel_check_window(ssh, c); 2351 } 2352 2353 static u_int 2354 read_mux(struct ssh *ssh, Channel *c, u_int need) 2355 { 2356 char buf[CHAN_RBUF]; 2357 ssize_t len; 2358 u_int rlen; 2359 int r; 2360 2361 if (sshbuf_len(c->input) < need) { 2362 rlen = need - sshbuf_len(c->input); 2363 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2364 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2365 return sshbuf_len(c->input); 2366 if (len <= 0) { 2367 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2368 c->self, c->rfd, len); 2369 chan_read_failed(ssh, c); 2370 return 0; 2371 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2372 fatal_fr(r, "channel %i: append", c->self); 2373 } 2374 return sshbuf_len(c->input); 2375 } 2376 2377 static void 2378 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2379 { 2380 u_int need; 2381 2382 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2383 return; 2384 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2385 return; 2386 if (c->mux_pause) 2387 return; 2388 2389 /* 2390 * Don't not read past the precise end of packets to 2391 * avoid disrupting fd passing. 2392 */ 2393 if (read_mux(ssh, c, 4) < 4) /* read header */ 2394 return; 2395 /* XXX sshbuf_peek_u32 */ 2396 need = PEEK_U32(sshbuf_ptr(c->input)); 2397 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2398 if (need > CHANNEL_MUX_MAX_PACKET) { 2399 debug2("channel %d: packet too big %u > %u", 2400 c->self, CHANNEL_MUX_MAX_PACKET, need); 2401 chan_rcvd_oclose(ssh, c); 2402 return; 2403 } 2404 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2405 return; 2406 if (c->mux_rcb(ssh, c) != 0) { 2407 debug("channel %d: mux_rcb failed", c->self); 2408 chan_mark_dead(ssh, c); 2409 return; 2410 } 2411 } 2412 2413 static void 2414 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2415 { 2416 ssize_t len; 2417 int r; 2418 2419 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2420 return; 2421 if (sshbuf_len(c->output) == 0) 2422 return; 2423 2424 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2425 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2426 return; 2427 if (len <= 0) { 2428 chan_mark_dead(ssh, c); 2429 return; 2430 } 2431 if ((r = sshbuf_consume(c->output, len)) != 0) 2432 fatal_fr(r, "channel %i: consume", c->self); 2433 } 2434 2435 static void 2436 channel_post_mux_client(struct ssh *ssh, Channel *c) 2437 { 2438 channel_post_mux_client_read(ssh, c); 2439 channel_post_mux_client_write(ssh, c); 2440 } 2441 2442 static void 2443 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2444 { 2445 Channel *nc; 2446 struct sockaddr_storage addr; 2447 socklen_t addrlen; 2448 int newsock; 2449 uid_t euid; 2450 gid_t egid; 2451 2452 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2453 return; 2454 2455 debug("multiplexing control connection"); 2456 2457 /* 2458 * Accept connection on control socket 2459 */ 2460 memset(&addr, 0, sizeof(addr)); 2461 addrlen = sizeof(addr); 2462 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2463 &addrlen)) == -1) { 2464 error_f("accept: %s", strerror(errno)); 2465 if (errno == EMFILE || errno == ENFILE) 2466 c->notbefore = monotime() + 1; 2467 return; 2468 } 2469 2470 if (getpeereid(newsock, &euid, &egid) == -1) { 2471 error_f("getpeereid failed: %s", strerror(errno)); 2472 close(newsock); 2473 return; 2474 } 2475 if ((euid != 0) && (getuid() != euid)) { 2476 error("multiplex uid mismatch: peer euid %u != uid %u", 2477 (u_int)euid, (u_int)getuid()); 2478 close(newsock); 2479 return; 2480 } 2481 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2482 newsock, newsock, -1, c->local_window_max, 2483 c->local_maxpacket, 0, "mux-control", 1); 2484 nc->mux_rcb = c->mux_rcb; 2485 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2486 /* establish state */ 2487 nc->mux_rcb(ssh, nc); 2488 /* mux state transitions must not elicit protocol messages */ 2489 nc->flags |= CHAN_LOCAL; 2490 } 2491 2492 static void 2493 channel_handler_init(struct ssh_channels *sc) 2494 { 2495 chan_fn **pre, **post; 2496 2497 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2498 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2499 fatal_f("allocation failed"); 2500 2501 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2502 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2503 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2504 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2505 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2506 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2507 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2508 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2509 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2510 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2511 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2512 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2513 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2514 2515 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2516 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2517 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2518 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2519 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2520 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2521 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2522 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2523 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2524 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2525 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2526 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2527 2528 sc->channel_pre = pre; 2529 sc->channel_post = post; 2530 } 2531 2532 /* gc dead channels */ 2533 static void 2534 channel_garbage_collect(struct ssh *ssh, Channel *c) 2535 { 2536 if (c == NULL) 2537 return; 2538 if (c->detach_user != NULL) { 2539 if (!chan_is_dead(ssh, c, c->detach_close)) 2540 return; 2541 2542 debug2("channel %d: gc: notify user", c->self); 2543 c->detach_user(ssh, c->self, 0, NULL); 2544 /* if we still have a callback */ 2545 if (c->detach_user != NULL) 2546 return; 2547 debug2("channel %d: gc: user detached", c->self); 2548 } 2549 if (!chan_is_dead(ssh, c, 1)) 2550 return; 2551 debug2("channel %d: garbage collecting", c->self); 2552 channel_free(ssh, c); 2553 } 2554 2555 enum channel_table { CHAN_PRE, CHAN_POST }; 2556 2557 static void 2558 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2559 { 2560 struct ssh_channels *sc = ssh->chanctxt; 2561 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2562 u_int i, oalloc; 2563 Channel *c; 2564 time_t now; 2565 2566 now = monotime(); 2567 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2568 c = sc->channels[i]; 2569 if (c == NULL) 2570 continue; 2571 /* Try to keep IO going while rekeying */ 2572 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2573 continue; 2574 if (c->delayed) { 2575 if (table == CHAN_PRE) 2576 c->delayed = 0; 2577 else 2578 continue; 2579 } 2580 if (ftab[c->type] != NULL) { 2581 if (table == CHAN_PRE && c->type == SSH_CHANNEL_OPEN && 2582 channel_get_expiry(ssh, c) != 0 && 2583 now >= channel_get_expiry(ssh, c)) { 2584 /* channel closed for inactivity */ 2585 verbose("channel %d: closing after %u seconds " 2586 "of inactivity", c->self, 2587 c->inactive_deadline); 2588 channel_force_close(ssh, c, 1); 2589 } else if (c->notbefore <= now) { 2590 /* Run handlers that are not paused. */ 2591 (*ftab[c->type])(ssh, c); 2592 /* inactivity timeouts must interrupt poll() */ 2593 if (timeout != NULL && 2594 c->type == SSH_CHANNEL_OPEN && 2595 channel_get_expiry(ssh, c) != 0) { 2596 ptimeout_deadline_monotime(timeout, 2597 channel_get_expiry(ssh, c)); 2598 } 2599 } else if (timeout != NULL) { 2600 /* 2601 * Arrange for poll() wakeup when channel pause 2602 * timer expires. 2603 */ 2604 ptimeout_deadline_monotime(timeout, 2605 c->notbefore); 2606 } 2607 } 2608 channel_garbage_collect(ssh, c); 2609 } 2610 } 2611 2612 /* 2613 * Create sockets before preparing IO. 2614 * This is necessary for things that need to happen after reading 2615 * the network-input but need to be completed before IO event setup, e.g. 2616 * because they may create new channels. 2617 */ 2618 static void 2619 channel_before_prepare_io(struct ssh *ssh) 2620 { 2621 struct ssh_channels *sc = ssh->chanctxt; 2622 Channel *c; 2623 u_int i, oalloc; 2624 2625 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2626 c = sc->channels[i]; 2627 if (c == NULL) 2628 continue; 2629 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2630 channel_before_prepare_io_rdynamic(ssh, c); 2631 } 2632 } 2633 2634 static void 2635 dump_channel_poll(const char *func, const char *what, Channel *c, 2636 u_int pollfd_offset, struct pollfd *pfd) 2637 { 2638 #ifdef DEBUG_CHANNEL_POLL 2639 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2640 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2641 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2642 c->rfd, c->wfd, c->efd, c->sock, 2643 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2644 c->io_want, c->io_ready, 2645 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2646 #endif 2647 } 2648 2649 /* Prepare pollfd entries for a single channel */ 2650 static void 2651 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2652 struct pollfd *pfd, u_int npfd) 2653 { 2654 u_int ev, p = *next_pollfd; 2655 2656 if (c == NULL) 2657 return; 2658 if (p + 4 > npfd) { 2659 /* Shouldn't happen */ 2660 fatal_f("channel %d: bad pfd offset %u (max %u)", 2661 c->self, p, npfd); 2662 } 2663 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2664 /* 2665 * prepare c->rfd 2666 * 2667 * This is a special case, since c->rfd might be the same as 2668 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2669 * IO too. 2670 */ 2671 if (c->rfd != -1) { 2672 ev = 0; 2673 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2674 ev |= POLLIN; 2675 /* rfd == wfd */ 2676 if (c->wfd == c->rfd) { 2677 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2678 ev |= POLLOUT; 2679 } 2680 /* rfd == efd */ 2681 if (c->efd == c->rfd) { 2682 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2683 ev |= POLLIN; 2684 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2685 ev |= POLLOUT; 2686 } 2687 /* rfd == sock */ 2688 if (c->sock == c->rfd) { 2689 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2690 ev |= POLLIN; 2691 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2692 ev |= POLLOUT; 2693 } 2694 /* Pack a pfd entry if any event armed for this fd */ 2695 if (ev != 0) { 2696 c->pfds[0] = p; 2697 pfd[p].fd = c->rfd; 2698 pfd[p].events = ev; 2699 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2700 p++; 2701 } 2702 } 2703 /* prepare c->wfd if wanting IO and not already handled above */ 2704 if (c->wfd != -1 && c->rfd != c->wfd) { 2705 ev = 0; 2706 if ((c->io_want & SSH_CHAN_IO_WFD)) 2707 ev |= POLLOUT; 2708 /* Pack a pfd entry if any event armed for this fd */ 2709 if (ev != 0) { 2710 c->pfds[1] = p; 2711 pfd[p].fd = c->wfd; 2712 pfd[p].events = ev; 2713 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2714 p++; 2715 } 2716 } 2717 /* prepare c->efd if wanting IO and not already handled above */ 2718 if (c->efd != -1 && c->rfd != c->efd) { 2719 ev = 0; 2720 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2721 ev |= POLLIN; 2722 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2723 ev |= POLLOUT; 2724 /* Pack a pfd entry if any event armed for this fd */ 2725 if (ev != 0) { 2726 c->pfds[2] = p; 2727 pfd[p].fd = c->efd; 2728 pfd[p].events = ev; 2729 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2730 p++; 2731 } 2732 } 2733 /* prepare c->sock if wanting IO and not already handled above */ 2734 if (c->sock != -1 && c->rfd != c->sock) { 2735 ev = 0; 2736 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2737 ev |= POLLIN; 2738 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2739 ev |= POLLOUT; 2740 /* Pack a pfd entry if any event armed for this fd */ 2741 if (ev != 0) { 2742 c->pfds[3] = p; 2743 pfd[p].fd = c->sock; 2744 pfd[p].events = 0; 2745 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2746 p++; 2747 } 2748 } 2749 *next_pollfd = p; 2750 } 2751 2752 /* * Allocate/prepare poll structure */ 2753 void 2754 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2755 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2756 { 2757 struct ssh_channels *sc = ssh->chanctxt; 2758 u_int i, oalloc, p, npfd = npfd_reserved; 2759 2760 channel_before_prepare_io(ssh); /* might create a new channel */ 2761 /* clear out I/O flags from last poll */ 2762 for (i = 0; i < sc->channels_alloc; i++) { 2763 if (sc->channels[i] == NULL) 2764 continue; 2765 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2766 } 2767 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2768 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2769 fatal_f("too many channels"); /* shouldn't happen */ 2770 npfd += sc->channels_alloc * 4; 2771 if (npfd > *npfd_allocp) { 2772 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2773 npfd, sizeof(**pfdp)); 2774 *npfd_allocp = npfd; 2775 } 2776 *npfd_activep = npfd_reserved; 2777 oalloc = sc->channels_alloc; 2778 2779 channel_handler(ssh, CHAN_PRE, timeout); 2780 2781 if (oalloc != sc->channels_alloc) { 2782 /* shouldn't happen */ 2783 fatal_f("channels_alloc changed during CHAN_PRE " 2784 "(was %u, now %u)", oalloc, sc->channels_alloc); 2785 } 2786 2787 /* Prepare pollfd */ 2788 p = npfd_reserved; 2789 for (i = 0; i < sc->channels_alloc; i++) 2790 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2791 *npfd_activep = p; 2792 } 2793 2794 static void 2795 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2796 const char *what, u_int revents_mask, u_int ready) 2797 { 2798 struct pollfd *pfd = &pfds[p]; 2799 2800 if (fd == -1) 2801 return; 2802 if (p == -1 || (u_int)p >= npfd) 2803 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2804 dump_channel_poll(__func__, what, c, p, pfd); 2805 if (pfd->fd != fd) { 2806 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2807 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2808 c->rfd, c->wfd, c->efd, c->sock); 2809 } 2810 if ((pfd->revents & POLLNVAL) != 0) { 2811 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2812 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2813 } 2814 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2815 c->io_ready |= ready & c->io_want; 2816 } 2817 2818 /* 2819 * After poll, perform any appropriate operations for channels which have 2820 * events pending. 2821 */ 2822 void 2823 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2824 { 2825 struct ssh_channels *sc = ssh->chanctxt; 2826 u_int i; 2827 int p; 2828 Channel *c; 2829 2830 #ifdef DEBUG_CHANNEL_POLL 2831 for (p = 0; p < (int)npfd; p++) { 2832 if (pfd[p].revents == 0) 2833 continue; 2834 debug_f("pfd[%u].fd %d rev 0x%04x", 2835 p, pfd[p].fd, pfd[p].revents); 2836 } 2837 #endif 2838 2839 /* Convert pollfd into c->io_ready */ 2840 for (i = 0; i < sc->channels_alloc; i++) { 2841 c = sc->channels[i]; 2842 if (c == NULL) 2843 continue; 2844 /* if rfd is shared with efd/sock then wfd should be too */ 2845 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2846 (c->rfd == c->efd || c->rfd == c->sock)) { 2847 /* Shouldn't happen */ 2848 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2849 c->self, c->rfd, c->wfd, c->efd, c->sock); 2850 } 2851 c->io_ready = 0; 2852 /* rfd, potentially shared with wfd, efd and sock */ 2853 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2854 fd_ready(c, p, pfd, npfd, c->rfd, 2855 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2856 if (c->rfd == c->wfd) { 2857 fd_ready(c, p, pfd, npfd, c->wfd, 2858 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2859 } 2860 if (c->rfd == c->efd) { 2861 fd_ready(c, p, pfd, npfd, c->efd, 2862 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2863 fd_ready(c, p, pfd, npfd, c->efd, 2864 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2865 } 2866 if (c->rfd == c->sock) { 2867 fd_ready(c, p, pfd, npfd, c->sock, 2868 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2869 fd_ready(c, p, pfd, npfd, c->sock, 2870 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2871 } 2872 dump_channel_poll(__func__, "rfd", c, p, pfd); 2873 } 2874 /* wfd */ 2875 if (c->wfd != -1 && c->wfd != c->rfd && 2876 (p = c->pfds[1]) != -1) { 2877 fd_ready(c, p, pfd, npfd, c->wfd, 2878 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2879 dump_channel_poll(__func__, "wfd", c, p, pfd); 2880 } 2881 /* efd */ 2882 if (c->efd != -1 && c->efd != c->rfd && 2883 (p = c->pfds[2]) != -1) { 2884 fd_ready(c, p, pfd, npfd, c->efd, 2885 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2886 fd_ready(c, p, pfd, npfd, c->efd, 2887 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2888 dump_channel_poll(__func__, "efd", c, p, pfd); 2889 } 2890 /* sock */ 2891 if (c->sock != -1 && c->sock != c->rfd && 2892 (p = c->pfds[3]) != -1) { 2893 fd_ready(c, p, pfd, npfd, c->sock, 2894 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2895 fd_ready(c, p, pfd, npfd, c->sock, 2896 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2897 dump_channel_poll(__func__, "sock", c, p, pfd); 2898 } 2899 } 2900 channel_handler(ssh, CHAN_POST, NULL); 2901 } 2902 2903 /* 2904 * Enqueue data for channels with open or draining c->input. 2905 * Returns non-zero if a packet was enqueued. 2906 */ 2907 static int 2908 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2909 { 2910 size_t len, plen; 2911 const u_char *pkt; 2912 int r; 2913 2914 if ((len = sshbuf_len(c->input)) == 0) { 2915 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2916 /* 2917 * input-buffer is empty and read-socket shutdown: 2918 * tell peer, that we will not send more data: 2919 * send IEOF. 2920 * hack for extended data: delay EOF if EFD still 2921 * in use. 2922 */ 2923 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2924 debug2("channel %d: " 2925 "ibuf_empty delayed efd %d/(%zu)", 2926 c->self, c->efd, sshbuf_len(c->extended)); 2927 else 2928 chan_ibuf_empty(ssh, c); 2929 } 2930 return 0; 2931 } 2932 2933 if (!c->have_remote_id) 2934 fatal_f("channel %d: no remote id", c->self); 2935 2936 if (c->datagram) { 2937 /* Check datagram will fit; drop if not */ 2938 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2939 fatal_fr(r, "channel %i: get datagram", c->self); 2940 /* 2941 * XXX this does tail-drop on the datagram queue which is 2942 * usually suboptimal compared to head-drop. Better to have 2943 * backpressure at read time? (i.e. read + discard) 2944 */ 2945 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2946 debug("channel %d: datagram too big", c->self); 2947 return 0; 2948 } 2949 /* Enqueue it */ 2950 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2951 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2952 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2953 (r = sshpkt_send(ssh)) != 0) 2954 fatal_fr(r, "channel %i: send datagram", c->self); 2955 c->remote_window -= plen; 2956 return 1; 2957 } 2958 2959 /* Enqueue packet for buffered data. */ 2960 if (len > c->remote_window) 2961 len = c->remote_window; 2962 if (len > c->remote_maxpacket) 2963 len = c->remote_maxpacket; 2964 if (len == 0) 2965 return 0; 2966 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2967 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2968 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2969 (r = sshpkt_send(ssh)) != 0) 2970 fatal_fr(r, "channel %i: send data", c->self); 2971 if ((r = sshbuf_consume(c->input, len)) != 0) 2972 fatal_fr(r, "channel %i: consume", c->self); 2973 c->remote_window -= len; 2974 return 1; 2975 } 2976 2977 /* 2978 * Enqueue data for channels with open c->extended in read mode. 2979 * Returns non-zero if a packet was enqueued. 2980 */ 2981 static int 2982 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2983 { 2984 size_t len; 2985 int r; 2986 2987 if ((len = sshbuf_len(c->extended)) == 0) 2988 return 0; 2989 2990 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2991 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2992 if (len > c->remote_window) 2993 len = c->remote_window; 2994 if (len > c->remote_maxpacket) 2995 len = c->remote_maxpacket; 2996 if (len == 0) 2997 return 0; 2998 if (!c->have_remote_id) 2999 fatal_f("channel %d: no remote id", c->self); 3000 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 3001 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3002 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 3003 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 3004 (r = sshpkt_send(ssh)) != 0) 3005 fatal_fr(r, "channel %i: data", c->self); 3006 if ((r = sshbuf_consume(c->extended, len)) != 0) 3007 fatal_fr(r, "channel %i: consume", c->self); 3008 c->remote_window -= len; 3009 debug2("channel %d: sent ext data %zu", c->self, len); 3010 return 1; 3011 } 3012 3013 /* 3014 * If there is data to send to the connection, enqueue some of it now. 3015 * Returns non-zero if data was enqueued. 3016 */ 3017 int 3018 channel_output_poll(struct ssh *ssh) 3019 { 3020 struct ssh_channels *sc = ssh->chanctxt; 3021 Channel *c; 3022 u_int i; 3023 int ret = 0; 3024 3025 for (i = 0; i < sc->channels_alloc; i++) { 3026 c = sc->channels[i]; 3027 if (c == NULL) 3028 continue; 3029 3030 /* 3031 * We are only interested in channels that can have buffered 3032 * incoming data. 3033 */ 3034 if (c->type != SSH_CHANNEL_OPEN) 3035 continue; 3036 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3037 /* XXX is this true? */ 3038 debug3("channel %d: will not send data after close", 3039 c->self); 3040 continue; 3041 } 3042 3043 /* Get the amount of buffered data for this channel. */ 3044 if (c->istate == CHAN_INPUT_OPEN || 3045 c->istate == CHAN_INPUT_WAIT_DRAIN) 3046 ret |= channel_output_poll_input_open(ssh, c); 3047 /* Send extended data, i.e. stderr */ 3048 if (!(c->flags & CHAN_EOF_SENT) && 3049 c->extended_usage == CHAN_EXTENDED_READ) 3050 ret |= channel_output_poll_extended_read(ssh, c); 3051 } 3052 return ret; 3053 } 3054 3055 /* -- mux proxy support */ 3056 3057 /* 3058 * When multiplexing channel messages for mux clients we have to deal 3059 * with downstream messages from the mux client and upstream messages 3060 * from the ssh server: 3061 * 1) Handling downstream messages is straightforward and happens 3062 * in channel_proxy_downstream(): 3063 * - We forward all messages (mostly) unmodified to the server. 3064 * - However, in order to route messages from upstream to the correct 3065 * downstream client, we have to replace the channel IDs used by the 3066 * mux clients with a unique channel ID because the mux clients might 3067 * use conflicting channel IDs. 3068 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3069 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3070 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3071 * with the newly allocated channel ID. 3072 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3073 * channels and processed by channel_proxy_upstream(). The local channel ID 3074 * is then translated back to the original mux client ID. 3075 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3076 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3077 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3078 * downstream mux client are removed. 3079 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3080 * requires more work, because they are not addressed to a specific 3081 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3082 * out whether the request is addressed to the local client or a 3083 * specific downstream client based on the listen-address/port. 3084 * 6) Agent and X11-Forwarding have a similar problem and are currently 3085 * not supported as the matching session/channel cannot be identified 3086 * easily. 3087 */ 3088 3089 /* 3090 * receive packets from downstream mux clients: 3091 * channel callback fired on read from mux client, creates 3092 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3093 * on channel creation. 3094 */ 3095 int 3096 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3097 { 3098 Channel *c = NULL; 3099 struct sshbuf *original = NULL, *modified = NULL; 3100 const u_char *cp; 3101 char *ctype = NULL, *listen_host = NULL; 3102 u_char type; 3103 size_t have; 3104 int ret = -1, r; 3105 u_int id, remote_id, listen_port; 3106 3107 /* sshbuf_dump(downstream->input, stderr); */ 3108 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3109 != 0) { 3110 error_fr(r, "parse"); 3111 return -1; 3112 } 3113 if (have < 2) { 3114 error_f("short message"); 3115 return -1; 3116 } 3117 type = cp[1]; 3118 /* skip padlen + type */ 3119 cp += 2; 3120 have -= 2; 3121 if (ssh_packet_log_type(type)) 3122 debug3_f("channel %u: down->up: type %u", 3123 downstream->self, type); 3124 3125 switch (type) { 3126 case SSH2_MSG_CHANNEL_OPEN: 3127 if ((original = sshbuf_from(cp, have)) == NULL || 3128 (modified = sshbuf_new()) == NULL) { 3129 error_f("alloc"); 3130 goto out; 3131 } 3132 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3133 (r = sshbuf_get_u32(original, &id)) != 0) { 3134 error_fr(r, "parse"); 3135 goto out; 3136 } 3137 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3138 -1, -1, -1, 0, 0, 0, ctype, 1); 3139 c->mux_ctx = downstream; /* point to mux client */ 3140 c->mux_downstream_id = id; /* original downstream id */ 3141 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3142 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3143 (r = sshbuf_putb(modified, original)) != 0) { 3144 error_fr(r, "compose"); 3145 channel_free(ssh, c); 3146 goto out; 3147 } 3148 break; 3149 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3150 /* 3151 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3152 * need to parse 'remote_id' instead of 'ctype'. 3153 */ 3154 if ((original = sshbuf_from(cp, have)) == NULL || 3155 (modified = sshbuf_new()) == NULL) { 3156 error_f("alloc"); 3157 goto out; 3158 } 3159 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3160 (r = sshbuf_get_u32(original, &id)) != 0) { 3161 error_fr(r, "parse"); 3162 goto out; 3163 } 3164 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3165 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3166 c->mux_ctx = downstream; /* point to mux client */ 3167 c->mux_downstream_id = id; 3168 c->remote_id = remote_id; 3169 c->have_remote_id = 1; 3170 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3171 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3172 (r = sshbuf_putb(modified, original)) != 0) { 3173 error_fr(r, "compose"); 3174 channel_free(ssh, c); 3175 goto out; 3176 } 3177 break; 3178 case SSH2_MSG_GLOBAL_REQUEST: 3179 if ((original = sshbuf_from(cp, have)) == NULL) { 3180 error_f("alloc"); 3181 goto out; 3182 } 3183 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3184 error_fr(r, "parse"); 3185 goto out; 3186 } 3187 if (strcmp(ctype, "tcpip-forward") != 0) { 3188 error_f("unsupported request %s", ctype); 3189 goto out; 3190 } 3191 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3192 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3193 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3194 error_fr(r, "parse"); 3195 goto out; 3196 } 3197 if (listen_port > 65535) { 3198 error_f("tcpip-forward for %s: bad port %u", 3199 listen_host, listen_port); 3200 goto out; 3201 } 3202 /* Record that connection to this host/port is permitted. */ 3203 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", 3204 -1, listen_host, NULL, (int)listen_port, downstream); 3205 break; 3206 case SSH2_MSG_CHANNEL_CLOSE: 3207 if (have < 4) 3208 break; 3209 remote_id = PEEK_U32(cp); 3210 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3211 if (c->flags & CHAN_CLOSE_RCVD) 3212 channel_free(ssh, c); 3213 else 3214 c->flags |= CHAN_CLOSE_SENT; 3215 } 3216 break; 3217 } 3218 if (modified) { 3219 if ((r = sshpkt_start(ssh, type)) != 0 || 3220 (r = sshpkt_putb(ssh, modified)) != 0 || 3221 (r = sshpkt_send(ssh)) != 0) { 3222 error_fr(r, "send"); 3223 goto out; 3224 } 3225 } else { 3226 if ((r = sshpkt_start(ssh, type)) != 0 || 3227 (r = sshpkt_put(ssh, cp, have)) != 0 || 3228 (r = sshpkt_send(ssh)) != 0) { 3229 error_fr(r, "send"); 3230 goto out; 3231 } 3232 } 3233 ret = 0; 3234 out: 3235 free(ctype); 3236 free(listen_host); 3237 sshbuf_free(original); 3238 sshbuf_free(modified); 3239 return ret; 3240 } 3241 3242 /* 3243 * receive packets from upstream server and de-multiplex packets 3244 * to correct downstream: 3245 * implemented as a helper for channel input handlers, 3246 * replaces local (proxy) channel ID with downstream channel ID. 3247 */ 3248 int 3249 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3250 { 3251 struct sshbuf *b = NULL; 3252 Channel *downstream; 3253 const u_char *cp = NULL; 3254 size_t len; 3255 int r; 3256 3257 /* 3258 * When receiving packets from the peer we need to check whether we 3259 * need to forward the packets to the mux client. In this case we 3260 * restore the original channel id and keep track of CLOSE messages, 3261 * so we can cleanup the channel. 3262 */ 3263 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3264 return 0; 3265 if ((downstream = c->mux_ctx) == NULL) 3266 return 0; 3267 switch (type) { 3268 case SSH2_MSG_CHANNEL_CLOSE: 3269 case SSH2_MSG_CHANNEL_DATA: 3270 case SSH2_MSG_CHANNEL_EOF: 3271 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3272 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3273 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3274 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3275 case SSH2_MSG_CHANNEL_SUCCESS: 3276 case SSH2_MSG_CHANNEL_FAILURE: 3277 case SSH2_MSG_CHANNEL_REQUEST: 3278 break; 3279 default: 3280 debug2_f("channel %u: unsupported type %u", c->self, type); 3281 return 0; 3282 } 3283 if ((b = sshbuf_new()) == NULL) { 3284 error_f("alloc reply"); 3285 goto out; 3286 } 3287 /* get remaining payload (after id) */ 3288 cp = sshpkt_ptr(ssh, &len); 3289 if (cp == NULL) { 3290 error_f("no packet"); 3291 goto out; 3292 } 3293 /* translate id and send to muxclient */ 3294 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3295 (r = sshbuf_put_u8(b, type)) != 0 || 3296 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3297 (r = sshbuf_put(b, cp, len)) != 0 || 3298 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3299 error_fr(r, "compose muxclient"); 3300 goto out; 3301 } 3302 /* sshbuf_dump(b, stderr); */ 3303 if (ssh_packet_log_type(type)) 3304 debug3_f("channel %u: up->down: type %u", c->self, type); 3305 out: 3306 /* update state */ 3307 switch (type) { 3308 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3309 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3310 if (cp && len > 4) { 3311 c->remote_id = PEEK_U32(cp); 3312 c->have_remote_id = 1; 3313 } 3314 break; 3315 case SSH2_MSG_CHANNEL_CLOSE: 3316 if (c->flags & CHAN_CLOSE_SENT) 3317 channel_free(ssh, c); 3318 else 3319 c->flags |= CHAN_CLOSE_RCVD; 3320 break; 3321 } 3322 sshbuf_free(b); 3323 return 1; 3324 } 3325 3326 /* -- protocol input */ 3327 3328 /* Parse a channel ID from the current packet */ 3329 static int 3330 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3331 { 3332 u_int32_t id; 3333 int r; 3334 3335 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3336 error_r(r, "%s: parse id", where); 3337 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3338 } 3339 if (id > INT_MAX) { 3340 error_r(r, "%s: bad channel id %u", where, id); 3341 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3342 } 3343 return (int)id; 3344 } 3345 3346 /* Lookup a channel from an ID in the current packet */ 3347 static Channel * 3348 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3349 { 3350 int id = channel_parse_id(ssh, where, what); 3351 Channel *c; 3352 3353 if ((c = channel_lookup(ssh, id)) == NULL) { 3354 ssh_packet_disconnect(ssh, 3355 "%s packet referred to nonexistent channel %d", what, id); 3356 } 3357 return c; 3358 } 3359 3360 int 3361 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3362 { 3363 const u_char *data; 3364 size_t data_len, win_len; 3365 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3366 int r; 3367 3368 if (channel_proxy_upstream(c, type, seq, ssh)) 3369 return 0; 3370 3371 /* Ignore any data for non-open channels (might happen on close) */ 3372 if (c->type != SSH_CHANNEL_OPEN && 3373 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3374 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3375 c->type != SSH_CHANNEL_X11_OPEN) 3376 return 0; 3377 3378 /* Get the data. */ 3379 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3380 (r = sshpkt_get_end(ssh)) != 0) 3381 fatal_fr(r, "channel %i: get data", c->self); 3382 3383 win_len = data_len; 3384 if (c->datagram) 3385 win_len += 4; /* string length header */ 3386 3387 /* 3388 * The sending side reduces its window as it sends data, so we 3389 * must 'fake' consumption of the data in order to ensure that window 3390 * updates are sent back. Otherwise the connection might deadlock. 3391 */ 3392 if (c->ostate != CHAN_OUTPUT_OPEN) { 3393 c->local_window -= win_len; 3394 c->local_consumed += win_len; 3395 return 0; 3396 } 3397 3398 if (win_len > c->local_maxpacket) { 3399 logit("channel %d: rcvd big packet %zu, maxpack %u", 3400 c->self, win_len, c->local_maxpacket); 3401 return 0; 3402 } 3403 if (win_len > c->local_window) { 3404 c->local_window_exceeded += win_len - c->local_window; 3405 logit("channel %d: rcvd too much data %zu, win %u/%u " 3406 "(excess %u)", c->self, win_len, c->local_window, 3407 c->local_window_max, c->local_window_exceeded); 3408 c->local_window = 0; 3409 /* Allow 10% grace before bringing the hammer down */ 3410 if (c->local_window_exceeded > (c->local_window_max / 10)) { 3411 ssh_packet_disconnect(ssh, "channel %d: peer ignored " 3412 "channel window", c->self); 3413 } 3414 } else { 3415 c->local_window -= win_len; 3416 c->local_window_exceeded = 0; 3417 } 3418 3419 if (c->datagram) { 3420 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3421 fatal_fr(r, "channel %i: append datagram", c->self); 3422 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3423 fatal_fr(r, "channel %i: append data", c->self); 3424 3425 return 0; 3426 } 3427 3428 int 3429 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3430 { 3431 const u_char *data; 3432 size_t data_len; 3433 u_int32_t tcode; 3434 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3435 int r; 3436 3437 if (channel_proxy_upstream(c, type, seq, ssh)) 3438 return 0; 3439 if (c->type != SSH_CHANNEL_OPEN) { 3440 logit("channel %d: ext data for non open", c->self); 3441 return 0; 3442 } 3443 if (c->flags & CHAN_EOF_RCVD) { 3444 if (ssh->compat & SSH_BUG_EXTEOF) 3445 debug("channel %d: accepting ext data after eof", 3446 c->self); 3447 else 3448 ssh_packet_disconnect(ssh, "Received extended_data " 3449 "after EOF on channel %d.", c->self); 3450 } 3451 3452 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3453 error_fr(r, "parse tcode"); 3454 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3455 } 3456 if (c->efd == -1 || 3457 c->extended_usage != CHAN_EXTENDED_WRITE || 3458 tcode != SSH2_EXTENDED_DATA_STDERR) { 3459 logit("channel %d: bad ext data", c->self); 3460 return 0; 3461 } 3462 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3463 (r = sshpkt_get_end(ssh)) != 0) { 3464 error_fr(r, "parse data"); 3465 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3466 } 3467 3468 if (data_len > c->local_window) { 3469 logit("channel %d: rcvd too much extended_data %zu, win %u", 3470 c->self, data_len, c->local_window); 3471 return 0; 3472 } 3473 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3474 /* XXX sshpkt_getb? */ 3475 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3476 error_fr(r, "append"); 3477 c->local_window -= data_len; 3478 return 0; 3479 } 3480 3481 int 3482 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3483 { 3484 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3485 int r; 3486 3487 if ((r = sshpkt_get_end(ssh)) != 0) { 3488 error_fr(r, "parse data"); 3489 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3490 } 3491 3492 if (channel_proxy_upstream(c, type, seq, ssh)) 3493 return 0; 3494 chan_rcvd_ieof(ssh, c); 3495 3496 /* XXX force input close */ 3497 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3498 debug("channel %d: FORCE input drain", c->self); 3499 c->istate = CHAN_INPUT_WAIT_DRAIN; 3500 if (sshbuf_len(c->input) == 0) 3501 chan_ibuf_empty(ssh, c); 3502 } 3503 return 0; 3504 } 3505 3506 int 3507 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3508 { 3509 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3510 int r; 3511 3512 if (channel_proxy_upstream(c, type, seq, ssh)) 3513 return 0; 3514 if ((r = sshpkt_get_end(ssh)) != 0) { 3515 error_fr(r, "parse data"); 3516 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3517 } 3518 chan_rcvd_oclose(ssh, c); 3519 return 0; 3520 } 3521 3522 int 3523 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3524 { 3525 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3526 u_int32_t remote_window, remote_maxpacket; 3527 int r; 3528 3529 if (channel_proxy_upstream(c, type, seq, ssh)) 3530 return 0; 3531 if (c->type != SSH_CHANNEL_OPENING) 3532 ssh_packet_disconnect(ssh, "Received open confirmation for " 3533 "non-opening channel %d.", c->self); 3534 /* 3535 * Record the remote channel number and mark that the channel 3536 * is now open. 3537 */ 3538 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3539 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3540 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3541 (r = sshpkt_get_end(ssh)) != 0) { 3542 error_fr(r, "window/maxpacket"); 3543 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3544 } 3545 3546 c->have_remote_id = 1; 3547 c->remote_window = remote_window; 3548 c->remote_maxpacket = remote_maxpacket; 3549 c->type = SSH_CHANNEL_OPEN; 3550 if (c->open_confirm) { 3551 debug2_f("channel %d: callback start", c->self); 3552 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3553 debug2_f("channel %d: callback done", c->self); 3554 } 3555 channel_set_used_time(ssh, c); 3556 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3557 c->remote_window, c->remote_maxpacket); 3558 return 0; 3559 } 3560 3561 static char * 3562 reason2txt(int reason) 3563 { 3564 switch (reason) { 3565 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3566 return "administratively prohibited"; 3567 case SSH2_OPEN_CONNECT_FAILED: 3568 return "connect failed"; 3569 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3570 return "unknown channel type"; 3571 case SSH2_OPEN_RESOURCE_SHORTAGE: 3572 return "resource shortage"; 3573 } 3574 return "unknown reason"; 3575 } 3576 3577 int 3578 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3579 { 3580 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3581 u_int32_t reason; 3582 char *msg = NULL; 3583 int r; 3584 3585 if (channel_proxy_upstream(c, type, seq, ssh)) 3586 return 0; 3587 if (c->type != SSH_CHANNEL_OPENING) 3588 ssh_packet_disconnect(ssh, "Received open failure for " 3589 "non-opening channel %d.", c->self); 3590 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3591 error_fr(r, "parse reason"); 3592 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3593 } 3594 /* skip language */ 3595 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3596 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3597 (r = sshpkt_get_end(ssh)) != 0) { 3598 error_fr(r, "parse msg/lang"); 3599 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3600 } 3601 logit("channel %d: open failed: %s%s%s", c->self, 3602 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3603 free(msg); 3604 if (c->open_confirm) { 3605 debug2_f("channel %d: callback start", c->self); 3606 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3607 debug2_f("channel %d: callback done", c->self); 3608 } 3609 /* Schedule the channel for cleanup/deletion. */ 3610 chan_mark_dead(ssh, c); 3611 return 0; 3612 } 3613 3614 int 3615 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3616 { 3617 int id = channel_parse_id(ssh, __func__, "window adjust"); 3618 Channel *c; 3619 u_int32_t adjust; 3620 u_int new_rwin; 3621 int r; 3622 3623 if ((c = channel_lookup(ssh, id)) == NULL) { 3624 logit("Received window adjust for non-open channel %d.", id); 3625 return 0; 3626 } 3627 3628 if (channel_proxy_upstream(c, type, seq, ssh)) 3629 return 0; 3630 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3631 (r = sshpkt_get_end(ssh)) != 0) { 3632 error_fr(r, "parse adjust"); 3633 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3634 } 3635 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3636 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3637 fatal("channel %d: adjust %u overflows remote window %u", 3638 c->self, adjust, c->remote_window); 3639 } 3640 c->remote_window = new_rwin; 3641 return 0; 3642 } 3643 3644 int 3645 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3646 { 3647 int id = channel_parse_id(ssh, __func__, "status confirm"); 3648 Channel *c; 3649 struct channel_confirm *cc; 3650 3651 /* Reset keepalive timeout */ 3652 ssh_packet_set_alive_timeouts(ssh, 0); 3653 3654 debug2_f("type %d id %d", type, id); 3655 3656 if ((c = channel_lookup(ssh, id)) == NULL) { 3657 logit_f("%d: unknown", id); 3658 return 0; 3659 } 3660 if (channel_proxy_upstream(c, type, seq, ssh)) 3661 return 0; 3662 if (sshpkt_get_end(ssh) != 0) 3663 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3664 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3665 return 0; 3666 cc->cb(ssh, type, c, cc->ctx); 3667 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3668 freezero(cc, sizeof(*cc)); 3669 return 0; 3670 } 3671 3672 /* -- tcp forwarding */ 3673 3674 void 3675 channel_set_af(struct ssh *ssh, int af) 3676 { 3677 ssh->chanctxt->IPv4or6 = af; 3678 } 3679 3680 3681 /* 3682 * Determine whether or not a port forward listens to loopback, the 3683 * specified address or wildcard. On the client, a specified bind 3684 * address will always override gateway_ports. On the server, a 3685 * gateway_ports of 1 (``yes'') will override the client's specification 3686 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3687 * will bind to whatever address the client asked for. 3688 * 3689 * Special-case listen_addrs are: 3690 * 3691 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3692 * "" (empty string), "*" -> wildcard v4/v6 3693 * "localhost" -> loopback v4/v6 3694 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3695 */ 3696 static const char * 3697 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3698 int is_client, struct ForwardOptions *fwd_opts) 3699 { 3700 const char *addr = NULL; 3701 int wildcard = 0; 3702 3703 if (listen_addr == NULL) { 3704 /* No address specified: default to gateway_ports setting */ 3705 if (fwd_opts->gateway_ports) 3706 wildcard = 1; 3707 } else if (fwd_opts->gateway_ports || is_client) { 3708 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3709 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3710 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3711 (!is_client && fwd_opts->gateway_ports == 1)) { 3712 wildcard = 1; 3713 /* 3714 * Notify client if they requested a specific listen 3715 * address and it was overridden. 3716 */ 3717 if (*listen_addr != '\0' && 3718 strcmp(listen_addr, "0.0.0.0") != 0 && 3719 strcmp(listen_addr, "*") != 0) { 3720 ssh_packet_send_debug(ssh, 3721 "Forwarding listen address " 3722 "\"%s\" overridden by server " 3723 "GatewayPorts", listen_addr); 3724 } 3725 } else if (strcmp(listen_addr, "localhost") != 0 || 3726 strcmp(listen_addr, "127.0.0.1") == 0 || 3727 strcmp(listen_addr, "::1") == 0) { 3728 /* 3729 * Accept explicit localhost address when 3730 * GatewayPorts=yes. The "localhost" hostname is 3731 * deliberately skipped here so it will listen on all 3732 * available local address families. 3733 */ 3734 addr = listen_addr; 3735 } 3736 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3737 strcmp(listen_addr, "::1") == 0) { 3738 /* 3739 * If a specific IPv4/IPv6 localhost address has been 3740 * requested then accept it even if gateway_ports is in 3741 * effect. This allows the client to prefer IPv4 or IPv6. 3742 */ 3743 addr = listen_addr; 3744 } 3745 if (wildcardp != NULL) 3746 *wildcardp = wildcard; 3747 return addr; 3748 } 3749 3750 static int 3751 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3752 struct Forward *fwd, int *allocated_listen_port, 3753 struct ForwardOptions *fwd_opts) 3754 { 3755 Channel *c; 3756 int sock, r, success = 0, wildcard = 0, is_client; 3757 struct addrinfo hints, *ai, *aitop; 3758 const char *host, *addr; 3759 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3760 in_port_t *lport_p; 3761 3762 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3763 3764 if (is_client && fwd->connect_path != NULL) { 3765 host = fwd->connect_path; 3766 } else { 3767 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3768 fwd->listen_host : fwd->connect_host; 3769 if (host == NULL) { 3770 error("No forward host name."); 3771 return 0; 3772 } 3773 if (strlen(host) >= NI_MAXHOST) { 3774 error("Forward host name too long."); 3775 return 0; 3776 } 3777 } 3778 3779 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3780 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3781 is_client, fwd_opts); 3782 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3783 (addr == NULL) ? "NULL" : addr); 3784 3785 /* 3786 * getaddrinfo returns a loopback address if the hostname is 3787 * set to NULL and hints.ai_flags is not AI_PASSIVE 3788 */ 3789 memset(&hints, 0, sizeof(hints)); 3790 hints.ai_family = ssh->chanctxt->IPv4or6; 3791 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3792 hints.ai_socktype = SOCK_STREAM; 3793 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3794 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3795 if (addr == NULL) { 3796 /* This really shouldn't happen */ 3797 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3798 ssh_gai_strerror(r)); 3799 } else { 3800 error_f("getaddrinfo(%.64s): %s", addr, 3801 ssh_gai_strerror(r)); 3802 } 3803 return 0; 3804 } 3805 if (allocated_listen_port != NULL) 3806 *allocated_listen_port = 0; 3807 for (ai = aitop; ai; ai = ai->ai_next) { 3808 switch (ai->ai_family) { 3809 case AF_INET: 3810 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3811 sin_port; 3812 break; 3813 case AF_INET6: 3814 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3815 sin6_port; 3816 break; 3817 default: 3818 continue; 3819 } 3820 /* 3821 * If allocating a port for -R forwards, then use the 3822 * same port for all address families. 3823 */ 3824 if (type == SSH_CHANNEL_RPORT_LISTENER && 3825 fwd->listen_port == 0 && allocated_listen_port != NULL && 3826 *allocated_listen_port > 0) 3827 *lport_p = htons(*allocated_listen_port); 3828 3829 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3830 strport, sizeof(strport), 3831 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3832 error_f("getnameinfo failed"); 3833 continue; 3834 } 3835 /* Create a port to listen for the host. */ 3836 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3837 if (sock == -1) { 3838 /* this is no error since kernel may not support ipv6 */ 3839 verbose("socket [%s]:%s: %.100s", ntop, strport, 3840 strerror(errno)); 3841 continue; 3842 } 3843 3844 set_reuseaddr(sock); 3845 3846 debug("Local forwarding listening on %s port %s.", 3847 ntop, strport); 3848 3849 /* Bind the socket to the address. */ 3850 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3851 /* 3852 * address can be in if use ipv6 address is 3853 * already bound 3854 */ 3855 verbose("bind [%s]:%s: %.100s", 3856 ntop, strport, strerror(errno)); 3857 close(sock); 3858 continue; 3859 } 3860 /* Start listening for connections on the socket. */ 3861 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3862 error("listen [%s]:%s: %.100s", ntop, strport, 3863 strerror(errno)); 3864 close(sock); 3865 continue; 3866 } 3867 3868 /* 3869 * fwd->listen_port == 0 requests a dynamically allocated port - 3870 * record what we got. 3871 */ 3872 if (type == SSH_CHANNEL_RPORT_LISTENER && 3873 fwd->listen_port == 0 && 3874 allocated_listen_port != NULL && 3875 *allocated_listen_port == 0) { 3876 *allocated_listen_port = get_local_port(sock); 3877 debug("Allocated listen port %d", 3878 *allocated_listen_port); 3879 } 3880 3881 /* Allocate a channel number for the socket. */ 3882 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3883 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3884 0, "port listener", 1); 3885 c->path = xstrdup(host); 3886 c->host_port = fwd->connect_port; 3887 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3888 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3889 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3890 c->listening_port = *allocated_listen_port; 3891 else 3892 c->listening_port = fwd->listen_port; 3893 success = 1; 3894 } 3895 if (success == 0) 3896 error_f("cannot listen to port: %d", fwd->listen_port); 3897 freeaddrinfo(aitop); 3898 return success; 3899 } 3900 3901 static int 3902 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3903 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3904 { 3905 struct sockaddr_un sunaddr; 3906 const char *path; 3907 Channel *c; 3908 int port, sock; 3909 mode_t omask; 3910 3911 switch (type) { 3912 case SSH_CHANNEL_UNIX_LISTENER: 3913 if (fwd->connect_path != NULL) { 3914 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3915 error("Local connecting path too long: %s", 3916 fwd->connect_path); 3917 return 0; 3918 } 3919 path = fwd->connect_path; 3920 port = PORT_STREAMLOCAL; 3921 } else { 3922 if (fwd->connect_host == NULL) { 3923 error("No forward host name."); 3924 return 0; 3925 } 3926 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3927 error("Forward host name too long."); 3928 return 0; 3929 } 3930 path = fwd->connect_host; 3931 port = fwd->connect_port; 3932 } 3933 break; 3934 case SSH_CHANNEL_RUNIX_LISTENER: 3935 path = fwd->listen_path; 3936 port = PORT_STREAMLOCAL; 3937 break; 3938 default: 3939 error_f("unexpected channel type %d", type); 3940 return 0; 3941 } 3942 3943 if (fwd->listen_path == NULL) { 3944 error("No forward path name."); 3945 return 0; 3946 } 3947 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3948 error("Local listening path too long: %s", fwd->listen_path); 3949 return 0; 3950 } 3951 3952 debug3_f("type %d path %s", type, fwd->listen_path); 3953 3954 /* Start a Unix domain listener. */ 3955 omask = umask(fwd_opts->streamlocal_bind_mask); 3956 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3957 fwd_opts->streamlocal_bind_unlink); 3958 umask(omask); 3959 if (sock < 0) 3960 return 0; 3961 3962 debug("Local forwarding listening on path %s.", fwd->listen_path); 3963 3964 /* Allocate a channel number for the socket. */ 3965 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 3966 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3967 0, "unix listener", 1); 3968 c->path = xstrdup(path); 3969 c->host_port = port; 3970 c->listening_port = PORT_STREAMLOCAL; 3971 c->listening_addr = xstrdup(fwd->listen_path); 3972 return 1; 3973 } 3974 3975 static int 3976 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3977 const char *host, u_short port) 3978 { 3979 u_int i; 3980 int found = 0; 3981 3982 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3983 Channel *c = ssh->chanctxt->channels[i]; 3984 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3985 continue; 3986 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3987 debug2_f("close channel %d", i); 3988 channel_free(ssh, c); 3989 found = 1; 3990 } 3991 } 3992 3993 return found; 3994 } 3995 3996 static int 3997 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3998 { 3999 u_int i; 4000 int found = 0; 4001 4002 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4003 Channel *c = ssh->chanctxt->channels[i]; 4004 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 4005 continue; 4006 if (c->path == NULL) 4007 continue; 4008 if (strcmp(c->path, path) == 0) { 4009 debug2_f("close channel %d", i); 4010 channel_free(ssh, c); 4011 found = 1; 4012 } 4013 } 4014 4015 return found; 4016 } 4017 4018 int 4019 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4020 { 4021 if (fwd->listen_path != NULL) { 4022 return channel_cancel_rport_listener_streamlocal(ssh, 4023 fwd->listen_path); 4024 } else { 4025 return channel_cancel_rport_listener_tcpip(ssh, 4026 fwd->listen_host, fwd->listen_port); 4027 } 4028 } 4029 4030 static int 4031 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4032 const char *lhost, u_short lport, int cport, 4033 struct ForwardOptions *fwd_opts) 4034 { 4035 u_int i; 4036 int found = 0; 4037 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4038 4039 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4040 Channel *c = ssh->chanctxt->channels[i]; 4041 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4042 continue; 4043 if (c->listening_port != lport) 4044 continue; 4045 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4046 /* skip dynamic forwardings */ 4047 if (c->host_port == 0) 4048 continue; 4049 } else { 4050 if (c->host_port != cport) 4051 continue; 4052 } 4053 if ((c->listening_addr == NULL && addr != NULL) || 4054 (c->listening_addr != NULL && addr == NULL)) 4055 continue; 4056 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4057 debug2_f("close channel %d", i); 4058 channel_free(ssh, c); 4059 found = 1; 4060 } 4061 } 4062 4063 return found; 4064 } 4065 4066 static int 4067 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4068 { 4069 u_int i; 4070 int found = 0; 4071 4072 if (path == NULL) { 4073 error_f("no path specified."); 4074 return 0; 4075 } 4076 4077 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4078 Channel *c = ssh->chanctxt->channels[i]; 4079 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4080 continue; 4081 if (c->listening_addr == NULL) 4082 continue; 4083 if (strcmp(c->listening_addr, path) == 0) { 4084 debug2_f("close channel %d", i); 4085 channel_free(ssh, c); 4086 found = 1; 4087 } 4088 } 4089 4090 return found; 4091 } 4092 4093 int 4094 channel_cancel_lport_listener(struct ssh *ssh, 4095 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4096 { 4097 if (fwd->listen_path != NULL) { 4098 return channel_cancel_lport_listener_streamlocal(ssh, 4099 fwd->listen_path); 4100 } else { 4101 return channel_cancel_lport_listener_tcpip(ssh, 4102 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4103 } 4104 } 4105 4106 /* protocol local port fwd, used by ssh */ 4107 int 4108 channel_setup_local_fwd_listener(struct ssh *ssh, 4109 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4110 { 4111 if (fwd->listen_path != NULL) { 4112 return channel_setup_fwd_listener_streamlocal(ssh, 4113 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4114 } else { 4115 return channel_setup_fwd_listener_tcpip(ssh, 4116 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4117 } 4118 } 4119 4120 /* Matches a remote forwarding permission against a requested forwarding */ 4121 static int 4122 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4123 { 4124 int ret; 4125 char *lhost; 4126 4127 /* XXX add ACLs for streamlocal */ 4128 if (fwd->listen_path != NULL) 4129 return 1; 4130 4131 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4132 return 0; 4133 4134 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4135 allowed_open->listen_port != fwd->listen_port) 4136 return 0; 4137 4138 /* Match hostnames case-insensitively */ 4139 lhost = xstrdup(fwd->listen_host); 4140 lowercase(lhost); 4141 ret = match_pattern(lhost, allowed_open->listen_host); 4142 free(lhost); 4143 4144 return ret; 4145 } 4146 4147 /* Checks whether a requested remote forwarding is permitted */ 4148 static int 4149 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4150 { 4151 struct ssh_channels *sc = ssh->chanctxt; 4152 struct permission_set *pset = &sc->remote_perms; 4153 u_int i, permit, permit_adm = 1; 4154 struct permission *perm; 4155 4156 /* XXX apply GatewayPorts override before checking? */ 4157 4158 permit = pset->all_permitted; 4159 if (!permit) { 4160 for (i = 0; i < pset->num_permitted_user; i++) { 4161 perm = &pset->permitted_user[i]; 4162 if (remote_open_match(perm, fwd)) { 4163 permit = 1; 4164 break; 4165 } 4166 } 4167 } 4168 4169 if (pset->num_permitted_admin > 0) { 4170 permit_adm = 0; 4171 for (i = 0; i < pset->num_permitted_admin; i++) { 4172 perm = &pset->permitted_admin[i]; 4173 if (remote_open_match(perm, fwd)) { 4174 permit_adm = 1; 4175 break; 4176 } 4177 } 4178 } 4179 4180 return permit && permit_adm; 4181 } 4182 4183 /* protocol v2 remote port fwd, used by sshd */ 4184 int 4185 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4186 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4187 { 4188 if (!check_rfwd_permission(ssh, fwd)) { 4189 ssh_packet_send_debug(ssh, "port forwarding refused"); 4190 if (fwd->listen_path != NULL) 4191 /* XXX always allowed, see remote_open_match() */ 4192 logit("Received request from %.100s port %d to " 4193 "remote forward to path \"%.100s\", " 4194 "but the request was denied.", 4195 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4196 fwd->listen_path); 4197 else if(fwd->listen_host != NULL) 4198 logit("Received request from %.100s port %d to " 4199 "remote forward to host %.100s port %d, " 4200 "but the request was denied.", 4201 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4202 fwd->listen_host, fwd->listen_port ); 4203 else 4204 logit("Received request from %.100s port %d to remote " 4205 "forward, but the request was denied.", 4206 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4207 return 0; 4208 } 4209 if (fwd->listen_path != NULL) { 4210 return channel_setup_fwd_listener_streamlocal(ssh, 4211 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4212 } else { 4213 return channel_setup_fwd_listener_tcpip(ssh, 4214 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4215 fwd_opts); 4216 } 4217 } 4218 4219 /* 4220 * Translate the requested rfwd listen host to something usable for 4221 * this server. 4222 */ 4223 static const char * 4224 channel_rfwd_bind_host(const char *listen_host) 4225 { 4226 if (listen_host == NULL) { 4227 return "localhost"; 4228 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4229 return ""; 4230 } else 4231 return listen_host; 4232 } 4233 4234 /* 4235 * Initiate forwarding of connections to port "port" on remote host through 4236 * the secure channel to host:port from local side. 4237 * Returns handle (index) for updating the dynamic listen port with 4238 * channel_update_permission(). 4239 */ 4240 int 4241 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4242 { 4243 int r, success = 0, idx = -1; 4244 const char *host_to_connect, *listen_host, *listen_path; 4245 int port_to_connect, listen_port; 4246 4247 /* Send the forward request to the remote side. */ 4248 if (fwd->listen_path != NULL) { 4249 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4250 (r = sshpkt_put_cstring(ssh, 4251 "streamlocal-forward@openssh.com")) != 0 || 4252 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4253 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4254 (r = sshpkt_send(ssh)) != 0 || 4255 (r = ssh_packet_write_wait(ssh)) != 0) 4256 fatal_fr(r, "request streamlocal"); 4257 } else { 4258 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4259 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4260 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4261 (r = sshpkt_put_cstring(ssh, 4262 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4263 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4264 (r = sshpkt_send(ssh)) != 0 || 4265 (r = ssh_packet_write_wait(ssh)) != 0) 4266 fatal_fr(r, "request tcpip-forward"); 4267 } 4268 /* Assume that server accepts the request */ 4269 success = 1; 4270 if (success) { 4271 /* Record that connection to this host/port is permitted. */ 4272 host_to_connect = listen_host = listen_path = NULL; 4273 port_to_connect = listen_port = 0; 4274 if (fwd->connect_path != NULL) { 4275 host_to_connect = fwd->connect_path; 4276 port_to_connect = PORT_STREAMLOCAL; 4277 } else { 4278 host_to_connect = fwd->connect_host; 4279 port_to_connect = fwd->connect_port; 4280 } 4281 if (fwd->listen_path != NULL) { 4282 listen_path = fwd->listen_path; 4283 listen_port = PORT_STREAMLOCAL; 4284 } else { 4285 listen_host = fwd->listen_host; 4286 listen_port = fwd->listen_port; 4287 } 4288 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4289 host_to_connect, port_to_connect, 4290 listen_host, listen_path, listen_port, NULL); 4291 } 4292 return idx; 4293 } 4294 4295 static int 4296 open_match(struct permission *allowed_open, const char *requestedhost, 4297 int requestedport) 4298 { 4299 if (allowed_open->host_to_connect == NULL) 4300 return 0; 4301 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4302 allowed_open->port_to_connect != requestedport) 4303 return 0; 4304 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4305 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4306 return 0; 4307 return 1; 4308 } 4309 4310 /* 4311 * Note that in the listen host/port case 4312 * we don't support FWD_PERMIT_ANY_PORT and 4313 * need to translate between the configured-host (listen_host) 4314 * and what we've sent to the remote server (channel_rfwd_bind_host) 4315 */ 4316 static int 4317 open_listen_match_tcpip(struct permission *allowed_open, 4318 const char *requestedhost, u_short requestedport, int translate) 4319 { 4320 const char *allowed_host; 4321 4322 if (allowed_open->host_to_connect == NULL) 4323 return 0; 4324 if (allowed_open->listen_port != requestedport) 4325 return 0; 4326 if (!translate && allowed_open->listen_host == NULL && 4327 requestedhost == NULL) 4328 return 1; 4329 allowed_host = translate ? 4330 channel_rfwd_bind_host(allowed_open->listen_host) : 4331 allowed_open->listen_host; 4332 if (allowed_host == NULL || requestedhost == NULL || 4333 strcmp(allowed_host, requestedhost) != 0) 4334 return 0; 4335 return 1; 4336 } 4337 4338 static int 4339 open_listen_match_streamlocal(struct permission *allowed_open, 4340 const char *requestedpath) 4341 { 4342 if (allowed_open->host_to_connect == NULL) 4343 return 0; 4344 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4345 return 0; 4346 if (allowed_open->listen_path == NULL || 4347 strcmp(allowed_open->listen_path, requestedpath) != 0) 4348 return 0; 4349 return 1; 4350 } 4351 4352 /* 4353 * Request cancellation of remote forwarding of connection host:port from 4354 * local side. 4355 */ 4356 static int 4357 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4358 const char *host, u_short port) 4359 { 4360 struct ssh_channels *sc = ssh->chanctxt; 4361 struct permission_set *pset = &sc->local_perms; 4362 int r; 4363 u_int i; 4364 struct permission *perm = NULL; 4365 4366 for (i = 0; i < pset->num_permitted_user; i++) { 4367 perm = &pset->permitted_user[i]; 4368 if (open_listen_match_tcpip(perm, host, port, 0)) 4369 break; 4370 perm = NULL; 4371 } 4372 if (perm == NULL) { 4373 debug_f("requested forward not found"); 4374 return -1; 4375 } 4376 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4377 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4378 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4379 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4380 (r = sshpkt_put_u32(ssh, port)) != 0 || 4381 (r = sshpkt_send(ssh)) != 0) 4382 fatal_fr(r, "send cancel"); 4383 4384 fwd_perm_clear(perm); /* unregister */ 4385 4386 return 0; 4387 } 4388 4389 /* 4390 * Request cancellation of remote forwarding of Unix domain socket 4391 * path from local side. 4392 */ 4393 static int 4394 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4395 { 4396 struct ssh_channels *sc = ssh->chanctxt; 4397 struct permission_set *pset = &sc->local_perms; 4398 int r; 4399 u_int i; 4400 struct permission *perm = NULL; 4401 4402 for (i = 0; i < pset->num_permitted_user; i++) { 4403 perm = &pset->permitted_user[i]; 4404 if (open_listen_match_streamlocal(perm, path)) 4405 break; 4406 perm = NULL; 4407 } 4408 if (perm == NULL) { 4409 debug_f("requested forward not found"); 4410 return -1; 4411 } 4412 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4413 (r = sshpkt_put_cstring(ssh, 4414 "cancel-streamlocal-forward@openssh.com")) != 0 || 4415 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4416 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4417 (r = sshpkt_send(ssh)) != 0) 4418 fatal_fr(r, "send cancel"); 4419 4420 fwd_perm_clear(perm); /* unregister */ 4421 4422 return 0; 4423 } 4424 4425 /* 4426 * Request cancellation of remote forwarding of a connection from local side. 4427 */ 4428 int 4429 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4430 { 4431 if (fwd->listen_path != NULL) { 4432 return channel_request_rforward_cancel_streamlocal(ssh, 4433 fwd->listen_path); 4434 } else { 4435 return channel_request_rforward_cancel_tcpip(ssh, 4436 fwd->listen_host, 4437 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4438 } 4439 } 4440 4441 /* 4442 * Permits opening to any host/port if permitted_user[] is empty. This is 4443 * usually called by the server, because the user could connect to any port 4444 * anyway, and the server has no way to know but to trust the client anyway. 4445 */ 4446 void 4447 channel_permit_all(struct ssh *ssh, int where) 4448 { 4449 struct permission_set *pset = permission_set_get(ssh, where); 4450 4451 if (pset->num_permitted_user == 0) 4452 pset->all_permitted = 1; 4453 } 4454 4455 /* 4456 * Permit the specified host/port for forwarding. 4457 */ 4458 void 4459 channel_add_permission(struct ssh *ssh, int who, int where, 4460 char *host, int port) 4461 { 4462 int local = where == FORWARD_LOCAL; 4463 struct permission_set *pset = permission_set_get(ssh, where); 4464 4465 debug("allow %s forwarding to host %s port %d", 4466 fwd_ident(who, where), host, port); 4467 /* 4468 * Remote forwards set listen_host/port, local forwards set 4469 * host/port_to_connect. 4470 */ 4471 permission_set_add(ssh, who, where, 4472 local ? host : 0, local ? port : 0, 4473 local ? NULL : host, NULL, local ? 0 : port, NULL); 4474 pset->all_permitted = 0; 4475 } 4476 4477 /* 4478 * Administratively disable forwarding. 4479 */ 4480 void 4481 channel_disable_admin(struct ssh *ssh, int where) 4482 { 4483 channel_clear_permission(ssh, FORWARD_ADM, where); 4484 permission_set_add(ssh, FORWARD_ADM, where, 4485 NULL, 0, NULL, NULL, 0, NULL); 4486 } 4487 4488 /* 4489 * Clear a list of permitted opens. 4490 */ 4491 void 4492 channel_clear_permission(struct ssh *ssh, int who, int where) 4493 { 4494 struct permission **permp; 4495 u_int *npermp; 4496 4497 permission_set_get_array(ssh, who, where, &permp, &npermp); 4498 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4499 *npermp = 0; 4500 } 4501 4502 /* 4503 * Update the listen port for a dynamic remote forward, after 4504 * the actual 'newport' has been allocated. If 'newport' < 0 is 4505 * passed then they entry will be invalidated. 4506 */ 4507 void 4508 channel_update_permission(struct ssh *ssh, int idx, int newport) 4509 { 4510 struct permission_set *pset = &ssh->chanctxt->local_perms; 4511 4512 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4513 debug_f("index out of range: %d num_permitted_user %d", 4514 idx, pset->num_permitted_user); 4515 return; 4516 } 4517 debug("%s allowed port %d for forwarding to host %s port %d", 4518 newport > 0 ? "Updating" : "Removing", 4519 newport, 4520 pset->permitted_user[idx].host_to_connect, 4521 pset->permitted_user[idx].port_to_connect); 4522 if (newport <= 0) 4523 fwd_perm_clear(&pset->permitted_user[idx]); 4524 else { 4525 pset->permitted_user[idx].listen_port = 4526 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4527 } 4528 } 4529 4530 /* Try to start non-blocking connect to next host in cctx list */ 4531 static int 4532 connect_next(struct channel_connect *cctx) 4533 { 4534 int sock, saved_errno; 4535 struct sockaddr_un *sunaddr; 4536 char ntop[NI_MAXHOST]; 4537 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4538 4539 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4540 switch (cctx->ai->ai_family) { 4541 case AF_UNIX: 4542 /* unix:pathname instead of host:port */ 4543 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4544 strlcpy(ntop, "unix", sizeof(ntop)); 4545 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4546 break; 4547 case AF_INET: 4548 case AF_INET6: 4549 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4550 ntop, sizeof(ntop), strport, sizeof(strport), 4551 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4552 error_f("getnameinfo failed"); 4553 continue; 4554 } 4555 break; 4556 default: 4557 continue; 4558 } 4559 debug_f("start for host %.100s ([%.100s]:%s)", 4560 cctx->host, ntop, strport); 4561 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4562 cctx->ai->ai_protocol)) == -1) { 4563 if (cctx->ai->ai_next == NULL) 4564 error("socket: %.100s", strerror(errno)); 4565 else 4566 verbose("socket: %.100s", strerror(errno)); 4567 continue; 4568 } 4569 if (set_nonblock(sock) == -1) 4570 fatal_f("set_nonblock(%d)", sock); 4571 if (connect(sock, cctx->ai->ai_addr, 4572 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4573 debug_f("host %.100s ([%.100s]:%s): %.100s", 4574 cctx->host, ntop, strport, strerror(errno)); 4575 saved_errno = errno; 4576 close(sock); 4577 errno = saved_errno; 4578 continue; /* fail -- try next */ 4579 } 4580 if (cctx->ai->ai_family != AF_UNIX) 4581 set_nodelay(sock); 4582 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4583 cctx->host, ntop, strport, sock); 4584 cctx->ai = cctx->ai->ai_next; 4585 return sock; 4586 } 4587 return -1; 4588 } 4589 4590 static void 4591 channel_connect_ctx_free(struct channel_connect *cctx) 4592 { 4593 free(cctx->host); 4594 if (cctx->aitop) { 4595 if (cctx->aitop->ai_family == AF_UNIX) 4596 free(cctx->aitop); 4597 else 4598 freeaddrinfo(cctx->aitop); 4599 } 4600 memset(cctx, 0, sizeof(*cctx)); 4601 } 4602 4603 /* 4604 * Return connecting socket to remote host:port or local socket path, 4605 * passing back the failure reason if appropriate. 4606 */ 4607 static int 4608 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4609 char *ctype, char *rname, struct channel_connect *cctx, 4610 int *reason, const char **errmsg) 4611 { 4612 struct addrinfo hints; 4613 int gaierr; 4614 int sock = -1; 4615 char strport[NI_MAXSERV]; 4616 4617 if (port == PORT_STREAMLOCAL) { 4618 struct sockaddr_un *sunaddr; 4619 struct addrinfo *ai; 4620 4621 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4622 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4623 return -1; 4624 } 4625 4626 /* 4627 * Fake up a struct addrinfo for AF_UNIX connections. 4628 * channel_connect_ctx_free() must check ai_family 4629 * and use free() not freeaddirinfo() for AF_UNIX. 4630 */ 4631 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4632 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4633 ai->ai_addr = (struct sockaddr *)(ai + 1); 4634 ai->ai_addrlen = sizeof(*sunaddr); 4635 ai->ai_family = AF_UNIX; 4636 ai->ai_socktype = socktype; 4637 ai->ai_protocol = PF_UNSPEC; 4638 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4639 sunaddr->sun_family = AF_UNIX; 4640 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4641 cctx->aitop = ai; 4642 } else { 4643 memset(&hints, 0, sizeof(hints)); 4644 hints.ai_family = ssh->chanctxt->IPv4or6; 4645 hints.ai_socktype = socktype; 4646 snprintf(strport, sizeof strport, "%d", port); 4647 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4648 != 0) { 4649 if (errmsg != NULL) 4650 *errmsg = ssh_gai_strerror(gaierr); 4651 if (reason != NULL) 4652 *reason = SSH2_OPEN_CONNECT_FAILED; 4653 error("connect_to %.100s: unknown host (%s)", name, 4654 ssh_gai_strerror(gaierr)); 4655 return -1; 4656 } 4657 } 4658 4659 cctx->host = xstrdup(name); 4660 cctx->port = port; 4661 cctx->ai = cctx->aitop; 4662 4663 if ((sock = connect_next(cctx)) == -1) { 4664 error("connect to %.100s port %d failed: %s", 4665 name, port, strerror(errno)); 4666 return -1; 4667 } 4668 4669 return sock; 4670 } 4671 4672 /* Return CONNECTING channel to remote host:port or local socket path */ 4673 static Channel * 4674 connect_to(struct ssh *ssh, const char *host, int port, 4675 char *ctype, char *rname) 4676 { 4677 struct channel_connect cctx; 4678 Channel *c; 4679 int sock; 4680 4681 memset(&cctx, 0, sizeof(cctx)); 4682 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4683 &cctx, NULL, NULL); 4684 if (sock == -1) { 4685 channel_connect_ctx_free(&cctx); 4686 return NULL; 4687 } 4688 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4689 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4690 c->host_port = port; 4691 c->path = xstrdup(host); 4692 c->connect_ctx = cctx; 4693 4694 return c; 4695 } 4696 4697 /* 4698 * returns either the newly connected channel or the downstream channel 4699 * that needs to deal with this connection. 4700 */ 4701 Channel * 4702 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4703 u_short listen_port, char *ctype, char *rname) 4704 { 4705 struct ssh_channels *sc = ssh->chanctxt; 4706 struct permission_set *pset = &sc->local_perms; 4707 u_int i; 4708 struct permission *perm; 4709 4710 for (i = 0; i < pset->num_permitted_user; i++) { 4711 perm = &pset->permitted_user[i]; 4712 if (open_listen_match_tcpip(perm, 4713 listen_host, listen_port, 1)) { 4714 if (perm->downstream) 4715 return perm->downstream; 4716 if (perm->port_to_connect == 0) 4717 return rdynamic_connect_prepare(ssh, 4718 ctype, rname); 4719 return connect_to(ssh, 4720 perm->host_to_connect, perm->port_to_connect, 4721 ctype, rname); 4722 } 4723 } 4724 error("WARNING: Server requests forwarding for unknown listen_port %d", 4725 listen_port); 4726 return NULL; 4727 } 4728 4729 Channel * 4730 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4731 char *ctype, char *rname) 4732 { 4733 struct ssh_channels *sc = ssh->chanctxt; 4734 struct permission_set *pset = &sc->local_perms; 4735 u_int i; 4736 struct permission *perm; 4737 4738 for (i = 0; i < pset->num_permitted_user; i++) { 4739 perm = &pset->permitted_user[i]; 4740 if (open_listen_match_streamlocal(perm, path)) { 4741 return connect_to(ssh, 4742 perm->host_to_connect, perm->port_to_connect, 4743 ctype, rname); 4744 } 4745 } 4746 error("WARNING: Server requests forwarding for unknown path %.100s", 4747 path); 4748 return NULL; 4749 } 4750 4751 /* Check if connecting to that port is permitted and connect. */ 4752 Channel * 4753 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4754 char *ctype, char *rname, int *reason, const char **errmsg) 4755 { 4756 struct ssh_channels *sc = ssh->chanctxt; 4757 struct permission_set *pset = &sc->local_perms; 4758 struct channel_connect cctx; 4759 Channel *c; 4760 u_int i, permit, permit_adm = 1; 4761 int sock; 4762 struct permission *perm; 4763 4764 permit = pset->all_permitted; 4765 if (!permit) { 4766 for (i = 0; i < pset->num_permitted_user; i++) { 4767 perm = &pset->permitted_user[i]; 4768 if (open_match(perm, host, port)) { 4769 permit = 1; 4770 break; 4771 } 4772 } 4773 } 4774 4775 if (pset->num_permitted_admin > 0) { 4776 permit_adm = 0; 4777 for (i = 0; i < pset->num_permitted_admin; i++) { 4778 perm = &pset->permitted_admin[i]; 4779 if (open_match(perm, host, port)) { 4780 permit_adm = 1; 4781 break; 4782 } 4783 } 4784 } 4785 4786 if (!permit || !permit_adm) { 4787 logit("Received request from %.100s port %d to connect to " 4788 "host %.100s port %d, but the request was denied.", 4789 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4790 if (reason != NULL) 4791 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4792 return NULL; 4793 } 4794 4795 memset(&cctx, 0, sizeof(cctx)); 4796 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4797 &cctx, reason, errmsg); 4798 if (sock == -1) { 4799 channel_connect_ctx_free(&cctx); 4800 return NULL; 4801 } 4802 4803 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4804 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4805 c->host_port = port; 4806 c->path = xstrdup(host); 4807 c->connect_ctx = cctx; 4808 4809 return c; 4810 } 4811 4812 /* Check if connecting to that path is permitted and connect. */ 4813 Channel * 4814 channel_connect_to_path(struct ssh *ssh, const char *path, 4815 char *ctype, char *rname) 4816 { 4817 struct ssh_channels *sc = ssh->chanctxt; 4818 struct permission_set *pset = &sc->local_perms; 4819 u_int i, permit, permit_adm = 1; 4820 struct permission *perm; 4821 4822 permit = pset->all_permitted; 4823 if (!permit) { 4824 for (i = 0; i < pset->num_permitted_user; i++) { 4825 perm = &pset->permitted_user[i]; 4826 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4827 permit = 1; 4828 break; 4829 } 4830 } 4831 } 4832 4833 if (pset->num_permitted_admin > 0) { 4834 permit_adm = 0; 4835 for (i = 0; i < pset->num_permitted_admin; i++) { 4836 perm = &pset->permitted_admin[i]; 4837 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4838 permit_adm = 1; 4839 break; 4840 } 4841 } 4842 } 4843 4844 if (!permit || !permit_adm) { 4845 logit("Received request to connect to path %.100s, " 4846 "but the request was denied.", path); 4847 return NULL; 4848 } 4849 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4850 } 4851 4852 void 4853 channel_send_window_changes(struct ssh *ssh) 4854 { 4855 struct ssh_channels *sc = ssh->chanctxt; 4856 struct winsize ws; 4857 int r; 4858 u_int i; 4859 4860 for (i = 0; i < sc->channels_alloc; i++) { 4861 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4862 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4863 continue; 4864 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4865 continue; 4866 channel_request_start(ssh, i, "window-change", 0); 4867 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4868 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4869 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4870 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4871 (r = sshpkt_send(ssh)) != 0) 4872 fatal_fr(r, "channel %u; send window-change", i); 4873 } 4874 } 4875 4876 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4877 static Channel * 4878 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4879 { 4880 Channel *c; 4881 int r; 4882 4883 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4884 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4885 c->host_port = 0; 4886 c->path = NULL; 4887 4888 /* 4889 * We need to open the channel before we have a FD, 4890 * so that we can get SOCKS header from peer. 4891 */ 4892 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4893 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4894 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4895 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4896 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4897 fatal_fr(r, "channel %i; confirm", c->self); 4898 return c; 4899 } 4900 4901 /* Return CONNECTING socket to remote host:port or local socket path */ 4902 static int 4903 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4904 { 4905 struct ssh_channels *sc = ssh->chanctxt; 4906 struct permission_set *pset = &sc->local_perms; 4907 struct permission *perm; 4908 struct channel_connect cctx; 4909 u_int i, permit_adm = 1; 4910 int sock; 4911 4912 if (pset->num_permitted_admin > 0) { 4913 permit_adm = 0; 4914 for (i = 0; i < pset->num_permitted_admin; i++) { 4915 perm = &pset->permitted_admin[i]; 4916 if (open_match(perm, c->path, c->host_port)) { 4917 permit_adm = 1; 4918 break; 4919 } 4920 } 4921 } 4922 if (!permit_adm) { 4923 debug_f("requested forward not permitted"); 4924 return -1; 4925 } 4926 4927 memset(&cctx, 0, sizeof(cctx)); 4928 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4929 NULL, &cctx, NULL, NULL); 4930 if (sock == -1) 4931 channel_connect_ctx_free(&cctx); 4932 else { 4933 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4934 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4935 c->connect_ctx = cctx; 4936 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4937 } 4938 return sock; 4939 } 4940 4941 /* -- X11 forwarding */ 4942 4943 /* 4944 * Creates an internet domain socket for listening for X11 connections. 4945 * Returns 0 and a suitable display number for the DISPLAY variable 4946 * stored in display_numberp , or -1 if an error occurs. 4947 */ 4948 int 4949 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4950 int x11_use_localhost, int single_connection, 4951 u_int *display_numberp, int **chanids) 4952 { 4953 Channel *nc = NULL; 4954 int display_number, sock, port; 4955 struct addrinfo hints, *ai, *aitop; 4956 char strport[NI_MAXSERV]; 4957 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4958 4959 if (chanids == NULL || x11_display_offset < 0 || 4960 x11_display_offset > UINT16_MAX - X11_BASE_PORT - MAX_DISPLAYS) 4961 return -1; 4962 4963 for (display_number = x11_display_offset; 4964 display_number < MAX_DISPLAYS; 4965 display_number++) { 4966 port = X11_BASE_PORT + display_number; 4967 memset(&hints, 0, sizeof(hints)); 4968 hints.ai_family = ssh->chanctxt->IPv4or6; 4969 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4970 hints.ai_socktype = SOCK_STREAM; 4971 snprintf(strport, sizeof strport, "%d", port); 4972 if ((gaierr = getaddrinfo(NULL, strport, 4973 &hints, &aitop)) != 0) { 4974 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4975 return -1; 4976 } 4977 for (ai = aitop; ai; ai = ai->ai_next) { 4978 if (ai->ai_family != AF_INET && 4979 ai->ai_family != AF_INET6) 4980 continue; 4981 sock = socket(ai->ai_family, ai->ai_socktype, 4982 ai->ai_protocol); 4983 if (sock == -1) { 4984 error("socket: %.100s", strerror(errno)); 4985 freeaddrinfo(aitop); 4986 return -1; 4987 } 4988 set_reuseaddr(sock); 4989 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4990 debug2_f("bind port %d: %.100s", port, 4991 strerror(errno)); 4992 close(sock); 4993 for (n = 0; n < num_socks; n++) 4994 close(socks[n]); 4995 num_socks = 0; 4996 break; 4997 } 4998 socks[num_socks++] = sock; 4999 if (num_socks == NUM_SOCKS) 5000 break; 5001 } 5002 freeaddrinfo(aitop); 5003 if (num_socks > 0) 5004 break; 5005 } 5006 if (display_number >= MAX_DISPLAYS) { 5007 error("Failed to allocate internet-domain X11 display socket."); 5008 return -1; 5009 } 5010 /* Start listening for connections on the socket. */ 5011 for (n = 0; n < num_socks; n++) { 5012 sock = socks[n]; 5013 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5014 error("listen: %.100s", strerror(errno)); 5015 close(sock); 5016 return -1; 5017 } 5018 } 5019 5020 /* Allocate a channel for each socket. */ 5021 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5022 for (n = 0; n < num_socks; n++) { 5023 sock = socks[n]; 5024 nc = channel_new(ssh, "x11-listener", 5025 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5026 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5027 0, "X11 inet listener", 1); 5028 nc->single_connection = single_connection; 5029 (*chanids)[n] = nc->self; 5030 } 5031 (*chanids)[n] = -1; 5032 5033 /* Return the display number for the DISPLAY environment variable. */ 5034 *display_numberp = display_number; 5035 return 0; 5036 } 5037 5038 static int 5039 connect_local_xsocket(u_int dnr) 5040 { 5041 int sock; 5042 struct sockaddr_un addr; 5043 5044 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5045 if (sock == -1) 5046 error("socket: %.100s", strerror(errno)); 5047 memset(&addr, 0, sizeof(addr)); 5048 addr.sun_family = AF_UNIX; 5049 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 5050 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5051 return sock; 5052 close(sock); 5053 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5054 return -1; 5055 } 5056 5057 int 5058 x11_connect_display(struct ssh *ssh) 5059 { 5060 u_int display_number; 5061 const char *display; 5062 char buf[1024], *cp; 5063 struct addrinfo hints, *ai, *aitop; 5064 char strport[NI_MAXSERV]; 5065 int gaierr, sock = 0; 5066 5067 /* Try to open a socket for the local X server. */ 5068 display = getenv("DISPLAY"); 5069 if (!display) { 5070 error("DISPLAY not set."); 5071 return -1; 5072 } 5073 /* 5074 * Now we decode the value of the DISPLAY variable and make a 5075 * connection to the real X server. 5076 */ 5077 5078 /* 5079 * Check if it is a unix domain socket. Unix domain displays are in 5080 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5081 */ 5082 if (strncmp(display, "unix:", 5) == 0 || 5083 display[0] == ':') { 5084 /* Connect to the unix domain socket. */ 5085 if (sscanf(strrchr(display, ':') + 1, "%u", 5086 &display_number) != 1) { 5087 error("Could not parse display number from DISPLAY: " 5088 "%.100s", display); 5089 return -1; 5090 } 5091 /* Create a socket. */ 5092 sock = connect_local_xsocket(display_number); 5093 if (sock < 0) 5094 return -1; 5095 5096 /* OK, we now have a connection to the display. */ 5097 return sock; 5098 } 5099 /* 5100 * Connect to an inet socket. The DISPLAY value is supposedly 5101 * hostname:d[.s], where hostname may also be numeric IP address. 5102 */ 5103 strlcpy(buf, display, sizeof(buf)); 5104 cp = strchr(buf, ':'); 5105 if (!cp) { 5106 error("Could not find ':' in DISPLAY: %.100s", display); 5107 return -1; 5108 } 5109 *cp = 0; 5110 /* 5111 * buf now contains the host name. But first we parse the 5112 * display number. 5113 */ 5114 if (sscanf(cp + 1, "%u", &display_number) != 1 || 5115 display_number > UINT16_MAX - X11_BASE_PORT) { 5116 error("Could not parse display number from DISPLAY: %.100s", 5117 display); 5118 return -1; 5119 } 5120 5121 /* Look up the host address */ 5122 memset(&hints, 0, sizeof(hints)); 5123 hints.ai_family = ssh->chanctxt->IPv4or6; 5124 hints.ai_socktype = SOCK_STREAM; 5125 snprintf(strport, sizeof strport, "%u", X11_BASE_PORT + display_number); 5126 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5127 error("%.100s: unknown host. (%s)", buf, 5128 ssh_gai_strerror(gaierr)); 5129 return -1; 5130 } 5131 for (ai = aitop; ai; ai = ai->ai_next) { 5132 /* Create a socket. */ 5133 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5134 if (sock == -1) { 5135 debug2("socket: %.100s", strerror(errno)); 5136 continue; 5137 } 5138 /* Connect it to the display. */ 5139 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5140 debug2("connect %.100s port %u: %.100s", buf, 5141 X11_BASE_PORT + display_number, strerror(errno)); 5142 close(sock); 5143 continue; 5144 } 5145 /* Success */ 5146 break; 5147 } 5148 freeaddrinfo(aitop); 5149 if (!ai) { 5150 error("connect %.100s port %u: %.100s", buf, 5151 X11_BASE_PORT + display_number, strerror(errno)); 5152 return -1; 5153 } 5154 set_nodelay(sock); 5155 return sock; 5156 } 5157 5158 /* 5159 * Requests forwarding of X11 connections, generates fake authentication 5160 * data, and enables authentication spoofing. 5161 * This should be called in the client only. 5162 */ 5163 void 5164 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5165 const char *disp, const char *proto, const char *data, int want_reply) 5166 { 5167 struct ssh_channels *sc = ssh->chanctxt; 5168 u_int data_len = (u_int) strlen(data) / 2; 5169 u_int i, value; 5170 const char *cp; 5171 char *new_data; 5172 int r, screen_number; 5173 5174 if (sc->x11_saved_display == NULL) 5175 sc->x11_saved_display = xstrdup(disp); 5176 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5177 error("x11_request_forwarding_with_spoofing: different " 5178 "$DISPLAY already forwarded"); 5179 return; 5180 } 5181 5182 cp = strchr(disp, ':'); 5183 if (cp) 5184 cp = strchr(cp, '.'); 5185 if (cp) 5186 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5187 else 5188 screen_number = 0; 5189 5190 if (sc->x11_saved_proto == NULL) { 5191 /* Save protocol name. */ 5192 sc->x11_saved_proto = xstrdup(proto); 5193 5194 /* Extract real authentication data. */ 5195 sc->x11_saved_data = xmalloc(data_len); 5196 for (i = 0; i < data_len; i++) { 5197 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5198 fatal("x11_request_forwarding: bad " 5199 "authentication data: %.100s", data); 5200 } 5201 sc->x11_saved_data[i] = value; 5202 } 5203 sc->x11_saved_data_len = data_len; 5204 5205 /* Generate fake data of the same length. */ 5206 sc->x11_fake_data = xmalloc(data_len); 5207 arc4random_buf(sc->x11_fake_data, data_len); 5208 sc->x11_fake_data_len = data_len; 5209 } 5210 5211 /* Convert the fake data into hex. */ 5212 new_data = tohex(sc->x11_fake_data, data_len); 5213 5214 /* Send the request packet. */ 5215 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5216 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5217 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5218 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5219 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5220 (r = sshpkt_send(ssh)) != 0 || 5221 (r = ssh_packet_write_wait(ssh)) != 0) 5222 fatal_fr(r, "send x11-req"); 5223 free(new_data); 5224 } 5225 5226 /* 5227 * Returns whether an x11 channel was used recently (less than a second ago) 5228 */ 5229 int 5230 x11_channel_used_recently(struct ssh *ssh) { 5231 u_int i; 5232 Channel *c; 5233 time_t lastused = 0; 5234 5235 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 5236 c = ssh->chanctxt->channels[i]; 5237 if (c == NULL || c->ctype == NULL || c->lastused == 0 || 5238 strcmp(c->ctype, "x11-connection") != 0) 5239 continue; 5240 lastused = c->lastused; 5241 } 5242 return lastused != 0 && monotime() > lastused + 1; 5243 } 5244