1 /* $NetBSD: channels.c,v 1.45 2024/09/24 21:32:18 christos Exp $ */ 2 /* $OpenBSD: channels.c,v 1.439 2024/07/25 22:40:08 djm Exp $ */ 3 4 /* 5 * Author: Tatu Ylonen <ylo@cs.hut.fi> 6 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 7 * All rights reserved 8 * This file contains functions for generic socket connection forwarding. 9 * There is also code for initiating connection forwarding for X11 connections, 10 * arbitrary tcp/ip connections, and the authentication agent connection. 11 * 12 * As far as I am concerned, the code I have written for this software 13 * can be used freely for any purpose. Any derived versions of this 14 * software must be clearly marked as such, and if the derived work is 15 * incompatible with the protocol description in the RFC file, it must be 16 * called by a name other than "ssh" or "Secure Shell". 17 * 18 * SSH2 support added by Markus Friedl. 19 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 20 * Copyright (c) 1999 Dug Song. All rights reserved. 21 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the above copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 33 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 34 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 35 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 36 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 38 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 39 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 41 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 42 */ 43 44 #include "includes.h" 45 __RCSID("$NetBSD: channels.c,v 1.45 2024/09/24 21:32:18 christos Exp $"); 46 #include <sys/param.h> 47 #include <sys/types.h> 48 #include <sys/stat.h> 49 #include <sys/ioctl.h> 50 #include <sys/un.h> 51 #include <sys/socket.h> 52 #include <sys/time.h> 53 #include <sys/queue.h> 54 55 #include <netinet/in.h> 56 #include <arpa/inet.h> 57 58 #include <errno.h> 59 #include <fcntl.h> 60 #include <limits.h> 61 #include <netdb.h> 62 #include <poll.h> 63 #include <stdarg.h> 64 #include <stdint.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <termios.h> 69 #include <unistd.h> 70 71 #include "xmalloc.h" 72 #include "ssh.h" 73 #include "ssh2.h" 74 #include "ssherr.h" 75 #include "sshbuf.h" 76 #include "packet.h" 77 #include "log.h" 78 #include "misc.h" 79 #include "channels.h" 80 #include "compat.h" 81 #include "canohost.h" 82 #include "sshkey.h" 83 #include "authfd.h" 84 #include "pathnames.h" 85 #include "match.h" 86 87 88 static int hpn_disabled = 0; 89 static int hpn_buffer_size = 2 * 1024 * 1024; 90 91 /* XXX remove once we're satisfied there's no lurking bugs */ 92 /* #define DEBUG_CHANNEL_POLL 1 */ 93 94 /* -- agent forwarding */ 95 #define NUM_SOCKS 10 96 97 /* -- X11 forwarding */ 98 /* Maximum number of fake X11 displays to try. */ 99 #define MAX_DISPLAYS 1000 100 101 /* Per-channel callback for pre/post IO actions */ 102 typedef void chan_fn(struct ssh *, Channel *c); 103 104 /* 105 * Data structure for storing which hosts are permitted for forward requests. 106 * The local sides of any remote forwards are stored in this array to prevent 107 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 108 * network (which might be behind a firewall). 109 */ 110 /* XXX: streamlocal wants a path instead of host:port */ 111 /* Overload host_to_connect; we could just make this match Forward */ 112 /* XXX - can we use listen_host instead of listen_path? */ 113 struct permission { 114 char *host_to_connect; /* Connect to 'host'. */ 115 int port_to_connect; /* Connect to 'port'. */ 116 char *listen_host; /* Remote side should listen address. */ 117 char *listen_path; /* Remote side should listen path. */ 118 int listen_port; /* Remote side should listen port. */ 119 Channel *downstream; /* Downstream mux*/ 120 }; 121 122 /* 123 * Stores the forwarding permission state for a single direction (local or 124 * remote). 125 */ 126 struct permission_set { 127 /* 128 * List of all local permitted host/port pairs to allow for the 129 * user. 130 */ 131 u_int num_permitted_user; 132 struct permission *permitted_user; 133 134 /* 135 * List of all permitted host/port pairs to allow for the admin. 136 */ 137 u_int num_permitted_admin; 138 struct permission *permitted_admin; 139 140 /* 141 * If this is true, all opens/listens are permitted. This is the 142 * case on the server on which we have to trust the client anyway, 143 * and the user could do anything after logging in. 144 */ 145 int all_permitted; 146 }; 147 148 /* Used to record timeouts per channel type */ 149 struct ssh_channel_timeout { 150 char *type_pattern; 151 int timeout_secs; 152 }; 153 154 /* Master structure for channels state */ 155 struct ssh_channels { 156 /* 157 * Pointer to an array containing all allocated channels. The array 158 * is dynamically extended as needed. 159 */ 160 Channel **channels; 161 162 /* 163 * Size of the channel array. All slots of the array must always be 164 * initialized (at least the type field); unused slots set to NULL 165 */ 166 u_int channels_alloc; 167 168 /* 169 * 'channel_pre*' are called just before IO to add any bits 170 * relevant to channels in the c->io_want bitmasks. 171 * 172 * 'channel_post*': perform any appropriate operations for 173 * channels which have c->io_ready events pending. 174 */ 175 chan_fn **channel_pre; 176 chan_fn **channel_post; 177 178 /* -- tcp forwarding */ 179 struct permission_set local_perms; 180 struct permission_set remote_perms; 181 182 /* -- X11 forwarding */ 183 184 /* Saved X11 local (client) display. */ 185 char *x11_saved_display; 186 187 /* Saved X11 authentication protocol name. */ 188 char *x11_saved_proto; 189 190 /* Saved X11 authentication data. This is the real data. */ 191 char *x11_saved_data; 192 u_int x11_saved_data_len; 193 194 /* Deadline after which all X11 connections are refused */ 195 time_t x11_refuse_time; 196 197 /* 198 * Fake X11 authentication data. This is what the server will be 199 * sending us; we should replace any occurrences of this by the 200 * real data. 201 */ 202 u_char *x11_fake_data; 203 u_int x11_fake_data_len; 204 205 /* AF_UNSPEC or AF_INET or AF_INET6 */ 206 int IPv4or6; 207 208 /* Channel timeouts by type */ 209 struct ssh_channel_timeout *timeouts; 210 size_t ntimeouts; 211 /* Global timeout for all OPEN channels */ 212 int global_deadline; 213 time_t lastused; 214 }; 215 216 /* helper */ 217 static void port_open_helper(struct ssh *ssh, Channel *c, const char *rtype); 218 static const char *channel_rfwd_bind_host(const char *listen_host); 219 220 /* non-blocking connect helpers */ 221 static int connect_next(struct channel_connect *); 222 static void channel_connect_ctx_free(struct channel_connect *); 223 static Channel *rdynamic_connect_prepare(struct ssh *, const char *, 224 const char *); 225 static int rdynamic_connect_finish(struct ssh *, Channel *); 226 227 /* Setup helper */ 228 static void channel_handler_init(struct ssh_channels *sc); 229 230 /* -- channel core */ 231 232 void 233 channel_init_channels(struct ssh *ssh) 234 { 235 struct ssh_channels *sc; 236 237 if ((sc = calloc(1, sizeof(*sc))) == NULL) 238 fatal_f("allocation failed"); 239 sc->channels_alloc = 10; 240 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 241 sc->IPv4or6 = AF_UNSPEC; 242 channel_handler_init(sc); 243 244 ssh->chanctxt = sc; 245 } 246 247 Channel * 248 channel_by_id(struct ssh *ssh, int id) 249 { 250 Channel *c; 251 252 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 253 logit_f("%d: bad id", id); 254 return NULL; 255 } 256 c = ssh->chanctxt->channels[id]; 257 if (c == NULL) { 258 logit_f("%d: bad id: channel free", id); 259 return NULL; 260 } 261 return c; 262 } 263 264 Channel * 265 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 266 { 267 Channel *c; 268 u_int i; 269 270 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 271 c = ssh->chanctxt->channels[i]; 272 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 273 return c; 274 } 275 return NULL; 276 } 277 278 /* 279 * Returns the channel if it is allowed to receive protocol messages. 280 * Private channels, like listening sockets, may not receive messages. 281 */ 282 Channel * 283 channel_lookup(struct ssh *ssh, int id) 284 { 285 Channel *c; 286 287 if ((c = channel_by_id(ssh, id)) == NULL) 288 return NULL; 289 290 switch (c->type) { 291 case SSH_CHANNEL_X11_OPEN: 292 case SSH_CHANNEL_LARVAL: 293 case SSH_CHANNEL_CONNECTING: 294 case SSH_CHANNEL_DYNAMIC: 295 case SSH_CHANNEL_RDYNAMIC_OPEN: 296 case SSH_CHANNEL_RDYNAMIC_FINISH: 297 case SSH_CHANNEL_OPENING: 298 case SSH_CHANNEL_OPEN: 299 case SSH_CHANNEL_ABANDONED: 300 case SSH_CHANNEL_MUX_PROXY: 301 return c; 302 } 303 logit("Non-public channel %d, type %d.", id, c->type); 304 return NULL; 305 } 306 307 /* 308 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 309 * match type_pattern. 310 */ 311 void 312 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 313 int timeout_secs) 314 { 315 struct ssh_channels *sc = ssh->chanctxt; 316 317 if (strcmp(type_pattern, "global") == 0) { 318 debug2_f("global channel timeout %d seconds", timeout_secs); 319 sc->global_deadline = timeout_secs; 320 return; 321 } 322 debug2_f("channel type \"%s\" timeout %d seconds", 323 type_pattern, timeout_secs); 324 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 325 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 326 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 327 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 328 sc->ntimeouts++; 329 } 330 331 /* Clears all previously-added channel timeouts */ 332 void 333 channel_clear_timeouts(struct ssh *ssh) 334 { 335 struct ssh_channels *sc = ssh->chanctxt; 336 size_t i; 337 338 debug3_f("clearing"); 339 for (i = 0; i < sc->ntimeouts; i++) 340 free(sc->timeouts[i].type_pattern); 341 free(sc->timeouts); 342 sc->timeouts = NULL; 343 sc->ntimeouts = 0; 344 } 345 346 static int 347 lookup_timeout(struct ssh *ssh, const char *type) 348 { 349 struct ssh_channels *sc = ssh->chanctxt; 350 size_t i; 351 352 for (i = 0; i < sc->ntimeouts; i++) { 353 if (match_pattern(type, sc->timeouts[i].type_pattern)) 354 return sc->timeouts[i].timeout_secs; 355 } 356 357 return 0; 358 } 359 360 /* 361 * Sets "extended type" of a channel; used by session layer to add additional 362 * information about channel types (e.g. shell, login, subsystem) that can then 363 * be used to select timeouts. 364 * Will reset c->inactive_deadline as a side-effect. 365 */ 366 void 367 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 368 { 369 Channel *c; 370 371 if ((c = channel_by_id(ssh, id)) == NULL) 372 fatal_f("missing channel %d", id); 373 if (c->xctype != NULL) 374 free(c->xctype); 375 c->xctype = xstrdup(xctype); 376 /* Type has changed, so look up inactivity deadline again */ 377 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 378 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 379 c->inactive_deadline); 380 } 381 382 /* 383 * update "last used" time on a channel. 384 * NB. nothing else should update lastused except to clear it. 385 */ 386 static void 387 channel_set_used_time(struct ssh *ssh, Channel *c) 388 { 389 ssh->chanctxt->lastused = monotime(); 390 if (c != NULL) 391 c->lastused = ssh->chanctxt->lastused; 392 } 393 394 /* 395 * Get the time at which a channel is due to time out for inactivity. 396 * Returns 0 if the channel is not due to time out ever. 397 */ 398 static time_t 399 channel_get_expiry(struct ssh *ssh, Channel *c) 400 { 401 struct ssh_channels *sc = ssh->chanctxt; 402 time_t expiry = 0, channel_expiry; 403 404 if (sc->lastused != 0 && sc->global_deadline != 0) 405 expiry = sc->lastused + sc->global_deadline; 406 if (c->lastused != 0 && c->inactive_deadline != 0) { 407 channel_expiry = c->lastused + c->inactive_deadline; 408 if (expiry == 0 || channel_expiry < expiry) 409 expiry = channel_expiry; 410 } 411 return expiry; 412 } 413 414 /* 415 * Register filedescriptors for a channel, used when allocating a channel or 416 * when the channel consumer/producer is ready, e.g. shell exec'd 417 */ 418 static void 419 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 420 int extusage, int nonblock, int is_tty) 421 { 422 int val; 423 424 if (rfd != -1) 425 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 426 if (wfd != -1 && wfd != rfd) 427 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 428 if (efd != -1 && efd != rfd && efd != wfd) 429 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 430 431 c->rfd = rfd; 432 c->wfd = wfd; 433 c->sock = (rfd == wfd) ? rfd : -1; 434 c->efd = efd; 435 c->extended_usage = extusage; 436 437 if ((c->isatty = is_tty) != 0) 438 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 439 440 /* enable nonblocking mode */ 441 c->restore_block = 0; 442 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 443 /* 444 * Special handling for stdio file descriptors: do not set 445 * non-blocking mode if they are TTYs. Otherwise prepare to 446 * restore their blocking state on exit to avoid interfering 447 * with other programs that follow. 448 */ 449 if (rfd != -1 && !isatty(rfd) && 450 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 451 c->restore_flags[0] = val; 452 c->restore_block |= CHANNEL_RESTORE_RFD; 453 set_nonblock(rfd); 454 } 455 if (wfd != -1 && !isatty(wfd) && 456 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 457 c->restore_flags[1] = val; 458 c->restore_block |= CHANNEL_RESTORE_WFD; 459 set_nonblock(wfd); 460 } 461 if (efd != -1 && !isatty(efd) && 462 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 463 c->restore_flags[2] = val; 464 c->restore_block |= CHANNEL_RESTORE_EFD; 465 set_nonblock(efd); 466 } 467 } else if (nonblock) { 468 if (rfd != -1) 469 set_nonblock(rfd); 470 if (wfd != -1) 471 set_nonblock(wfd); 472 if (efd != -1) 473 set_nonblock(efd); 474 } 475 /* channel might be entering a larval state, so reset global timeout */ 476 channel_set_used_time(ssh, NULL); 477 } 478 479 /* 480 * Allocate a new channel object and set its type and socket. 481 */ 482 Channel * 483 channel_new(struct ssh *ssh, const char *ctype, int type, int rfd, int wfd, 484 int efd, u_int window, u_int maxpack, int extusage, const char *remote_name, 485 int nonblock) 486 { 487 struct ssh_channels *sc = ssh->chanctxt; 488 u_int i, found = 0 /* XXXGCC12 */; 489 Channel *c; 490 int r; 491 492 /* Try to find a free slot where to put the new channel. */ 493 for (i = 0; i < sc->channels_alloc; i++) { 494 if (sc->channels[i] == NULL) { 495 /* Found a free slot. */ 496 found = i; 497 break; 498 } 499 } 500 if (i >= sc->channels_alloc) { 501 /* 502 * There are no free slots. Take last+1 slot and expand 503 * the array. 504 */ 505 found = sc->channels_alloc; 506 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 507 fatal_f("internal error: channels_alloc %d too big", 508 sc->channels_alloc); 509 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 510 sc->channels_alloc + 10, sizeof(*sc->channels)); 511 sc->channels_alloc += 10; 512 debug2("channel: expanding %d", sc->channels_alloc); 513 } 514 /* Initialize and return new channel. */ 515 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 516 if ((c->input = sshbuf_new()) == NULL || 517 (c->output = sshbuf_new()) == NULL || 518 (c->extended = sshbuf_new()) == NULL) 519 fatal_f("sshbuf_new failed"); 520 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 521 fatal_fr(r, "sshbuf_set_max_size"); 522 c->ostate = CHAN_OUTPUT_OPEN; 523 c->istate = CHAN_INPUT_OPEN; 524 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 525 c->self = found; 526 c->type = type; 527 c->ctype = __UNCONST(ctype); 528 c->local_window = window; 529 c->local_window_max = window; 530 c->local_maxpacket = maxpack; 531 c->dynamic_window = 0; 532 c->remote_id = -1; 533 c->remote_name = xstrdup(remote_name); 534 c->ctl_chan = -1; 535 c->delayed = 1; /* prevent call to channel_post handler */ 536 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 537 TAILQ_INIT(&c->status_confirms); 538 debug("channel %d: new %s [%s] (inactive timeout: %u)", 539 found, c->ctype, remote_name, c->inactive_deadline); 540 return c; 541 } 542 543 int 544 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 545 { 546 int ret, fd = *fdp; 547 548 if (fd == -1) 549 return 0; 550 551 /* restore blocking */ 552 if (*fdp == c->rfd && 553 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 554 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 555 else if (*fdp == c->wfd && 556 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 557 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 558 else if (*fdp == c->efd && 559 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 560 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 561 562 if (*fdp == c->rfd) { 563 c->io_want &= ~SSH_CHAN_IO_RFD; 564 c->io_ready &= ~SSH_CHAN_IO_RFD; 565 c->rfd = -1; 566 c->pfds[0] = -1; 567 } 568 if (*fdp == c->wfd) { 569 c->io_want &= ~SSH_CHAN_IO_WFD; 570 c->io_ready &= ~SSH_CHAN_IO_WFD; 571 c->wfd = -1; 572 c->pfds[1] = -1; 573 } 574 if (*fdp == c->efd) { 575 c->io_want &= ~SSH_CHAN_IO_EFD; 576 c->io_ready &= ~SSH_CHAN_IO_EFD; 577 c->efd = -1; 578 c->pfds[2] = -1; 579 } 580 if (*fdp == c->sock) { 581 c->io_want &= ~SSH_CHAN_IO_SOCK; 582 c->io_ready &= ~SSH_CHAN_IO_SOCK; 583 c->sock = -1; 584 c->pfds[3] = -1; 585 } 586 587 ret = close(fd); 588 *fdp = -1; /* probably redundant */ 589 return ret; 590 } 591 592 /* Close all channel fd/socket. */ 593 static void 594 channel_close_fds(struct ssh *ssh, Channel *c) 595 { 596 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 597 598 channel_close_fd(ssh, c, &c->sock); 599 if (rfd != sock) 600 channel_close_fd(ssh, c, &c->rfd); 601 if (wfd != sock && wfd != rfd) 602 channel_close_fd(ssh, c, &c->wfd); 603 if (efd != sock && efd != rfd && efd != wfd) 604 channel_close_fd(ssh, c, &c->efd); 605 } 606 607 static void 608 fwd_perm_clear(struct permission *perm) 609 { 610 free(perm->host_to_connect); 611 free(perm->listen_host); 612 free(perm->listen_path); 613 memset(perm, 0, sizeof(*perm)); 614 } 615 616 /* Returns an printable name for the specified forwarding permission list */ 617 static const char * 618 fwd_ident(int who, int where) 619 { 620 if (who == FORWARD_ADM) { 621 if (where == FORWARD_LOCAL) 622 return "admin local"; 623 else if (where == FORWARD_REMOTE) 624 return "admin remote"; 625 } else if (who == FORWARD_USER) { 626 if (where == FORWARD_LOCAL) 627 return "user local"; 628 else if (where == FORWARD_REMOTE) 629 return "user remote"; 630 } 631 fatal("Unknown forward permission list %d/%d", who, where); 632 } 633 634 /* Returns the forwarding permission list for the specified direction */ 635 static struct permission_set * 636 permission_set_get(struct ssh *ssh, int where) 637 { 638 struct ssh_channels *sc = ssh->chanctxt; 639 640 switch (where) { 641 case FORWARD_LOCAL: 642 return &sc->local_perms; 643 break; 644 case FORWARD_REMOTE: 645 return &sc->remote_perms; 646 break; 647 default: 648 fatal_f("invalid forwarding direction %d", where); 649 } 650 } 651 652 /* Returns pointers to the specified forwarding list and its element count */ 653 static void 654 permission_set_get_array(struct ssh *ssh, int who, int where, 655 struct permission ***permpp, u_int **npermpp) 656 { 657 struct permission_set *pset = permission_set_get(ssh, where); 658 659 switch (who) { 660 case FORWARD_USER: 661 *permpp = &pset->permitted_user; 662 *npermpp = &pset->num_permitted_user; 663 break; 664 case FORWARD_ADM: 665 *permpp = &pset->permitted_admin; 666 *npermpp = &pset->num_permitted_admin; 667 break; 668 default: 669 fatal_f("invalid forwarding client %d", who); 670 } 671 } 672 673 /* Adds an entry to the specified forwarding list */ 674 static int 675 permission_set_add(struct ssh *ssh, int who, int where, 676 const char *host_to_connect, int port_to_connect, 677 const char *listen_host, const char *listen_path, int listen_port, 678 Channel *downstream) 679 { 680 struct permission **permp; 681 u_int n, *npermp; 682 683 permission_set_get_array(ssh, who, where, &permp, &npermp); 684 685 if (*npermp >= INT_MAX) 686 fatal_f("%s overflow", fwd_ident(who, where)); 687 688 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 689 n = (*npermp)++; 690 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 691 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 692 (*permp)[n].port_to_connect = port_to_connect; 693 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 694 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 695 (*permp)[n].listen_port = listen_port; 696 (*permp)[n].downstream = downstream; 697 #undef MAYBE_DUP 698 return (int)n; 699 } 700 701 static void 702 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 703 { 704 struct ssh_channels *sc = ssh->chanctxt; 705 struct permission_set *pset = &sc->local_perms; 706 struct permission *perm; 707 int r; 708 u_int i; 709 710 for (i = 0; i < pset->num_permitted_user; i++) { 711 perm = &pset->permitted_user[i]; 712 if (perm->downstream != c) 713 continue; 714 715 /* cancel on the server, since mux client is gone */ 716 debug("channel %d: cleanup remote forward for %s:%u", 717 c->self, perm->listen_host, perm->listen_port); 718 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 719 (r = sshpkt_put_cstring(ssh, 720 "cancel-tcpip-forward")) != 0 || 721 (r = sshpkt_put_u8(ssh, 0)) != 0 || 722 (r = sshpkt_put_cstring(ssh, 723 channel_rfwd_bind_host(perm->listen_host))) != 0 || 724 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 725 (r = sshpkt_send(ssh)) != 0) { 726 fatal_fr(r, "channel %i", c->self); 727 } 728 fwd_perm_clear(perm); /* unregister */ 729 } 730 } 731 732 /* Free the channel and close its fd/socket. */ 733 void 734 channel_free(struct ssh *ssh, Channel *c) 735 { 736 struct ssh_channels *sc = ssh->chanctxt; 737 char *s; 738 u_int i, n; 739 Channel *other; 740 struct channel_confirm *cc; 741 742 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 743 if ((other = sc->channels[i]) == NULL) 744 continue; 745 n++; 746 /* detach from mux client and prepare for closing */ 747 if (c->type == SSH_CHANNEL_MUX_CLIENT && 748 other->type == SSH_CHANNEL_MUX_PROXY && 749 other->mux_ctx == c) { 750 other->mux_ctx = NULL; 751 other->type = SSH_CHANNEL_OPEN; 752 other->istate = CHAN_INPUT_CLOSED; 753 other->ostate = CHAN_OUTPUT_CLOSED; 754 } 755 } 756 debug("channel %d: free: %s, nchannels %u", c->self, 757 c->remote_name ? c->remote_name : "???", n); 758 759 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 760 mux_remove_remote_forwardings(ssh, c); 761 free(c->mux_ctx); 762 c->mux_ctx = NULL; 763 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 764 free(c->mux_ctx); 765 c->mux_ctx = NULL; 766 } 767 768 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 769 s = channel_open_message(ssh); 770 debug3("channel %d: status: %s", c->self, s); 771 free(s); 772 } 773 774 channel_close_fds(ssh, c); 775 sshbuf_free(c->input); 776 sshbuf_free(c->output); 777 sshbuf_free(c->extended); 778 c->input = c->output = c->extended = NULL; 779 free(c->remote_name); 780 c->remote_name = NULL; 781 free(c->path); 782 c->path = NULL; 783 free(c->listening_addr); 784 c->listening_addr = NULL; 785 free(c->xctype); 786 c->xctype = NULL; 787 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 788 if (cc->abandon_cb != NULL) 789 cc->abandon_cb(ssh, c, cc->ctx); 790 TAILQ_REMOVE(&c->status_confirms, cc, entry); 791 freezero(cc, sizeof(*cc)); 792 } 793 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 794 c->filter_cleanup(ssh, c->self, c->filter_ctx); 795 sc->channels[c->self] = NULL; 796 freezero(c, sizeof(*c)); 797 } 798 799 void 800 channel_free_all(struct ssh *ssh) 801 { 802 u_int i; 803 struct ssh_channels *sc = ssh->chanctxt; 804 805 for (i = 0; i < sc->channels_alloc; i++) 806 if (sc->channels[i] != NULL) 807 channel_free(ssh, sc->channels[i]); 808 809 free(sc->channels); 810 sc->channels = NULL; 811 sc->channels_alloc = 0; 812 813 free(sc->x11_saved_display); 814 sc->x11_saved_display = NULL; 815 816 free(sc->x11_saved_proto); 817 sc->x11_saved_proto = NULL; 818 819 free(sc->x11_saved_data); 820 sc->x11_saved_data = NULL; 821 sc->x11_saved_data_len = 0; 822 823 free(sc->x11_fake_data); 824 sc->x11_fake_data = NULL; 825 sc->x11_fake_data_len = 0; 826 } 827 828 /* 829 * Closes the sockets/fds of all channels. This is used to close extra file 830 * descriptors after a fork. 831 */ 832 void 833 channel_close_all(struct ssh *ssh) 834 { 835 u_int i; 836 837 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 838 if (ssh->chanctxt->channels[i] != NULL) 839 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 840 } 841 842 /* 843 * Stop listening to channels. 844 */ 845 void 846 channel_stop_listening(struct ssh *ssh) 847 { 848 u_int i; 849 Channel *c; 850 851 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 852 c = ssh->chanctxt->channels[i]; 853 if (c != NULL) { 854 switch (c->type) { 855 case SSH_CHANNEL_AUTH_SOCKET: 856 case SSH_CHANNEL_PORT_LISTENER: 857 case SSH_CHANNEL_RPORT_LISTENER: 858 case SSH_CHANNEL_X11_LISTENER: 859 case SSH_CHANNEL_UNIX_LISTENER: 860 case SSH_CHANNEL_RUNIX_LISTENER: 861 channel_close_fd(ssh, c, &c->sock); 862 channel_free(ssh, c); 863 break; 864 } 865 } 866 } 867 } 868 869 /* 870 * Returns true if no channel has too much buffered data, and false if one or 871 * more channel is overfull. 872 */ 873 int 874 channel_not_very_much_buffered_data(struct ssh *ssh) 875 { 876 u_int i; 877 u_int maxsize = ssh_packet_get_maxsize(ssh); 878 Channel *c; 879 880 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 881 c = ssh->chanctxt->channels[i]; 882 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 883 continue; 884 if (sshbuf_len(c->output) > maxsize) { 885 debug2("channel %d: big output buffer %zu > %u", 886 c->self, sshbuf_len(c->output), maxsize); 887 return 0; 888 } 889 } 890 return 1; 891 } 892 893 /* Returns true if any channel is still open. */ 894 int 895 channel_still_open(struct ssh *ssh) 896 { 897 u_int i; 898 Channel *c; 899 900 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 901 c = ssh->chanctxt->channels[i]; 902 if (c == NULL) 903 continue; 904 switch (c->type) { 905 case SSH_CHANNEL_X11_LISTENER: 906 case SSH_CHANNEL_PORT_LISTENER: 907 case SSH_CHANNEL_RPORT_LISTENER: 908 case SSH_CHANNEL_MUX_LISTENER: 909 case SSH_CHANNEL_CLOSED: 910 case SSH_CHANNEL_AUTH_SOCKET: 911 case SSH_CHANNEL_DYNAMIC: 912 case SSH_CHANNEL_RDYNAMIC_OPEN: 913 case SSH_CHANNEL_CONNECTING: 914 case SSH_CHANNEL_ZOMBIE: 915 case SSH_CHANNEL_ABANDONED: 916 case SSH_CHANNEL_UNIX_LISTENER: 917 case SSH_CHANNEL_RUNIX_LISTENER: 918 continue; 919 case SSH_CHANNEL_LARVAL: 920 continue; 921 case SSH_CHANNEL_OPENING: 922 case SSH_CHANNEL_OPEN: 923 case SSH_CHANNEL_RDYNAMIC_FINISH: 924 case SSH_CHANNEL_X11_OPEN: 925 case SSH_CHANNEL_MUX_CLIENT: 926 case SSH_CHANNEL_MUX_PROXY: 927 return 1; 928 default: 929 fatal_f("bad channel type %d", c->type); 930 /* NOTREACHED */ 931 } 932 } 933 return 0; 934 } 935 936 /* Returns true if a channel with a TTY is open. */ 937 int 938 channel_tty_open(struct ssh *ssh) 939 { 940 u_int i; 941 Channel *c; 942 943 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 944 c = ssh->chanctxt->channels[i]; 945 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 946 continue; 947 if (c->client_tty) 948 return 1; 949 } 950 return 0; 951 } 952 953 /* Returns the id of an open channel suitable for keepaliving */ 954 int 955 channel_find_open(struct ssh *ssh) 956 { 957 u_int i; 958 Channel *c; 959 960 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 961 c = ssh->chanctxt->channels[i]; 962 if (c == NULL || !c->have_remote_id) 963 continue; 964 switch (c->type) { 965 case SSH_CHANNEL_CLOSED: 966 case SSH_CHANNEL_DYNAMIC: 967 case SSH_CHANNEL_RDYNAMIC_OPEN: 968 case SSH_CHANNEL_RDYNAMIC_FINISH: 969 case SSH_CHANNEL_X11_LISTENER: 970 case SSH_CHANNEL_PORT_LISTENER: 971 case SSH_CHANNEL_RPORT_LISTENER: 972 case SSH_CHANNEL_MUX_LISTENER: 973 case SSH_CHANNEL_MUX_CLIENT: 974 case SSH_CHANNEL_MUX_PROXY: 975 case SSH_CHANNEL_OPENING: 976 case SSH_CHANNEL_CONNECTING: 977 case SSH_CHANNEL_ZOMBIE: 978 case SSH_CHANNEL_ABANDONED: 979 case SSH_CHANNEL_UNIX_LISTENER: 980 case SSH_CHANNEL_RUNIX_LISTENER: 981 continue; 982 case SSH_CHANNEL_LARVAL: 983 case SSH_CHANNEL_AUTH_SOCKET: 984 case SSH_CHANNEL_OPEN: 985 case SSH_CHANNEL_X11_OPEN: 986 return i; 987 default: 988 fatal_f("bad channel type %d", c->type); 989 /* NOTREACHED */ 990 } 991 } 992 return -1; 993 } 994 995 /* Returns the state of the channel's extended usage flag */ 996 const char * 997 channel_format_extended_usage(const Channel *c) 998 { 999 if (c->efd == -1) 1000 return "closed"; 1001 1002 switch (c->extended_usage) { 1003 case CHAN_EXTENDED_WRITE: 1004 return "write"; 1005 case CHAN_EXTENDED_READ: 1006 return "read"; 1007 case CHAN_EXTENDED_IGNORE: 1008 return "ignore"; 1009 default: 1010 return "UNKNOWN"; 1011 } 1012 } 1013 1014 static char * 1015 channel_format_status(const Channel *c) 1016 { 1017 char *ret = NULL; 1018 1019 xasprintf(&ret, "t%d [%s] %s%u %s%u i%u/%zu o%u/%zu e[%s]/%zu " 1020 "fd %d/%d/%d sock %d cc %d %s%u io 0x%02x/0x%02x", 1021 c->type, c->xctype != NULL ? c->xctype : c->ctype, 1022 c->have_remote_id ? "r" : "nr", c->remote_id, 1023 c->mux_ctx != NULL ? "m" : "nm", c->mux_downstream_id, 1024 c->istate, sshbuf_len(c->input), 1025 c->ostate, sshbuf_len(c->output), 1026 channel_format_extended_usage(c), sshbuf_len(c->extended), 1027 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 1028 c->have_ctl_child_id ? "c" : "nc", c->ctl_child_id, 1029 c->io_want, c->io_ready); 1030 return ret; 1031 } 1032 1033 /* 1034 * Returns a message describing the currently open forwarded connections, 1035 * suitable for sending to the client. The message contains crlf pairs for 1036 * newlines. 1037 */ 1038 char * 1039 channel_open_message(struct ssh *ssh) 1040 { 1041 struct sshbuf *buf; 1042 Channel *c; 1043 u_int i; 1044 int r; 1045 char *cp, *ret; 1046 1047 if ((buf = sshbuf_new()) == NULL) 1048 fatal_f("sshbuf_new"); 1049 if ((r = sshbuf_putf(buf, 1050 "The following connections are open:\r\n")) != 0) 1051 fatal_fr(r, "sshbuf_putf"); 1052 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1053 c = ssh->chanctxt->channels[i]; 1054 if (c == NULL) 1055 continue; 1056 switch (c->type) { 1057 case SSH_CHANNEL_X11_LISTENER: 1058 case SSH_CHANNEL_PORT_LISTENER: 1059 case SSH_CHANNEL_RPORT_LISTENER: 1060 case SSH_CHANNEL_CLOSED: 1061 case SSH_CHANNEL_AUTH_SOCKET: 1062 case SSH_CHANNEL_ZOMBIE: 1063 case SSH_CHANNEL_ABANDONED: 1064 case SSH_CHANNEL_MUX_LISTENER: 1065 case SSH_CHANNEL_UNIX_LISTENER: 1066 case SSH_CHANNEL_RUNIX_LISTENER: 1067 continue; 1068 case SSH_CHANNEL_LARVAL: 1069 case SSH_CHANNEL_OPENING: 1070 case SSH_CHANNEL_CONNECTING: 1071 case SSH_CHANNEL_DYNAMIC: 1072 case SSH_CHANNEL_RDYNAMIC_OPEN: 1073 case SSH_CHANNEL_RDYNAMIC_FINISH: 1074 case SSH_CHANNEL_OPEN: 1075 case SSH_CHANNEL_X11_OPEN: 1076 case SSH_CHANNEL_MUX_PROXY: 1077 case SSH_CHANNEL_MUX_CLIENT: 1078 cp = channel_format_status(c); 1079 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1080 c->self, c->remote_name, cp)) != 0) { 1081 free(cp); 1082 fatal_fr(r, "sshbuf_putf"); 1083 } 1084 free(cp); 1085 continue; 1086 default: 1087 fatal_f("bad channel type %d", c->type); 1088 /* NOTREACHED */ 1089 } 1090 } 1091 if ((ret = sshbuf_dup_string(buf)) == NULL) 1092 fatal_f("sshbuf_dup_string"); 1093 sshbuf_free(buf); 1094 return ret; 1095 } 1096 1097 static void 1098 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1099 { 1100 int r; 1101 1102 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1103 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1104 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1105 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1106 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1107 fatal_r(r, "%s: channel %i: open", where, c->self); 1108 } 1109 } 1110 1111 void 1112 channel_send_open(struct ssh *ssh, int id) 1113 { 1114 Channel *c = channel_lookup(ssh, id); 1115 int r; 1116 1117 if (c == NULL) { 1118 logit("channel_send_open: %d: bad id", id); 1119 return; 1120 } 1121 debug2("channel %d: send open", id); 1122 open_preamble(ssh, __func__, c, c->ctype); 1123 if ((r = sshpkt_send(ssh)) != 0) 1124 fatal_fr(r, "channel %i", c->self); 1125 } 1126 1127 void 1128 channel_request_start(struct ssh *ssh, int id, const char *service, 1129 int wantconfirm) 1130 { 1131 Channel *c = channel_lookup(ssh, id); 1132 int r; 1133 1134 if (c == NULL) { 1135 logit_f("%d: unknown channel id", id); 1136 return; 1137 } 1138 if (!c->have_remote_id) 1139 fatal_f("channel %d: no remote id", c->self); 1140 1141 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1142 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1143 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1144 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1145 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1146 fatal_fr(r, "channel %i", c->self); 1147 } 1148 } 1149 1150 void 1151 channel_register_status_confirm(struct ssh *ssh, int id, 1152 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1153 { 1154 struct channel_confirm *cc; 1155 Channel *c; 1156 1157 if ((c = channel_lookup(ssh, id)) == NULL) 1158 fatal_f("%d: bad id", id); 1159 1160 cc = xcalloc(1, sizeof(*cc)); 1161 cc->cb = cb; 1162 cc->abandon_cb = abandon_cb; 1163 cc->ctx = ctx; 1164 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1165 } 1166 1167 void 1168 channel_register_open_confirm(struct ssh *ssh, int id, 1169 channel_open_fn *fn, void *ctx) 1170 { 1171 Channel *c = channel_lookup(ssh, id); 1172 1173 if (c == NULL) { 1174 logit_f("%d: bad id", id); 1175 return; 1176 } 1177 c->open_confirm = fn; 1178 c->open_confirm_ctx = ctx; 1179 } 1180 1181 void 1182 channel_register_cleanup(struct ssh *ssh, int id, 1183 channel_callback_fn *fn, int do_close) 1184 { 1185 Channel *c = channel_by_id(ssh, id); 1186 1187 if (c == NULL) { 1188 logit_f("%d: bad id", id); 1189 return; 1190 } 1191 c->detach_user = fn; 1192 c->detach_close = do_close; 1193 } 1194 1195 void 1196 channel_cancel_cleanup(struct ssh *ssh, int id) 1197 { 1198 Channel *c = channel_by_id(ssh, id); 1199 1200 if (c == NULL) { 1201 logit_f("%d: bad id", id); 1202 return; 1203 } 1204 c->detach_user = NULL; 1205 c->detach_close = 0; 1206 } 1207 1208 void 1209 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1210 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1211 { 1212 Channel *c = channel_lookup(ssh, id); 1213 1214 if (c == NULL) { 1215 logit_f("%d: bad id", id); 1216 return; 1217 } 1218 c->input_filter = ifn; 1219 c->output_filter = ofn; 1220 c->filter_ctx = ctx; 1221 c->filter_cleanup = cfn; 1222 } 1223 1224 void 1225 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1226 int extusage, int nonblock, int is_tty, u_int window_max) 1227 { 1228 Channel *c = channel_lookup(ssh, id); 1229 int r; 1230 1231 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1232 fatal("channel_activate for non-larval channel %d.", id); 1233 if (!c->have_remote_id) 1234 fatal_f("channel %d: no remote id", c->self); 1235 1236 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1237 c->type = SSH_CHANNEL_OPEN; 1238 channel_set_used_time(ssh, c); 1239 c->local_window = c->local_window_max = window_max; 1240 1241 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1242 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1243 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1244 (r = sshpkt_send(ssh)) != 0) 1245 fatal_fr(r, "channel %i", c->self); 1246 } 1247 1248 static void 1249 channel_pre_listener(struct ssh *ssh, Channel *c) 1250 { 1251 c->io_want = SSH_CHAN_IO_SOCK_R; 1252 } 1253 1254 static void 1255 channel_pre_connecting(struct ssh *ssh, Channel *c) 1256 { 1257 debug3("channel %d: waiting for connection", c->self); 1258 c->io_want = SSH_CHAN_IO_SOCK_W; 1259 } 1260 1261 static int 1262 channel_tcpwinsz(struct ssh *ssh) 1263 { 1264 u_int32_t tcpwinsz = 0; 1265 socklen_t optsz = sizeof(tcpwinsz); 1266 int ret = -1; 1267 1268 /* if we aren't on a socket return 128KB*/ 1269 if(!ssh_packet_connection_is_on_socket(ssh)) 1270 return(128*1024); 1271 ret = getsockopt(ssh_packet_get_connection_in(ssh), 1272 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz); 1273 /* return no more than SSHBUF_SIZE_MAX (currently 256MB) */ 1274 if ((ret == 0) && tcpwinsz > SSHBUF_SIZE_MAX) 1275 tcpwinsz = SSHBUF_SIZE_MAX; 1276 debug2("tcpwinsz: %d for connection: %d", tcpwinsz, 1277 ssh_packet_get_connection_in(ssh)); 1278 return(tcpwinsz); 1279 } 1280 1281 static void 1282 channel_pre_open(struct ssh *ssh, Channel *c) 1283 { 1284 c->io_want = 0; 1285 if (c->istate == CHAN_INPUT_OPEN && 1286 c->remote_window > 0 && 1287 sshbuf_len(c->input) < c->remote_window && 1288 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1289 c->io_want |= SSH_CHAN_IO_RFD; 1290 if (c->ostate == CHAN_OUTPUT_OPEN || 1291 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1292 if (sshbuf_len(c->output) > 0) { 1293 c->io_want |= SSH_CHAN_IO_WFD; 1294 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1295 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1296 debug2("channel %d: " 1297 "obuf_empty delayed efd %d/(%zu)", c->self, 1298 c->efd, sshbuf_len(c->extended)); 1299 else 1300 chan_obuf_empty(ssh, c); 1301 } 1302 } 1303 /** XXX check close conditions, too */ 1304 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1305 c->ostate == CHAN_OUTPUT_CLOSED)) { 1306 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1307 sshbuf_len(c->extended) > 0) 1308 c->io_want |= SSH_CHAN_IO_EFD_W; 1309 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1310 (c->extended_usage == CHAN_EXTENDED_READ || 1311 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1312 sshbuf_len(c->extended) < c->remote_window) 1313 c->io_want |= SSH_CHAN_IO_EFD_R; 1314 } 1315 /* XXX: What about efd? races? */ 1316 } 1317 1318 /* 1319 * This is a special state for X11 authentication spoofing. An opened X11 1320 * connection (when authentication spoofing is being done) remains in this 1321 * state until the first packet has been completely read. The authentication 1322 * data in that packet is then substituted by the real data if it matches the 1323 * fake data, and the channel is put into normal mode. 1324 * XXX All this happens at the client side. 1325 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1326 */ 1327 static int 1328 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1329 { 1330 struct ssh_channels *sc = ssh->chanctxt; 1331 u_char *ucp; 1332 u_int proto_len, data_len; 1333 1334 /* Is this being called after the refusal deadline? */ 1335 if (sc->x11_refuse_time != 0 && 1336 monotime() >= sc->x11_refuse_time) { 1337 verbose("Rejected X11 connection after ForwardX11Timeout " 1338 "expired"); 1339 return -1; 1340 } 1341 1342 /* Check if the fixed size part of the packet is in buffer. */ 1343 if (sshbuf_len(b) < 12) 1344 return 0; 1345 1346 /* Parse the lengths of variable-length fields. */ 1347 ucp = sshbuf_mutable_ptr(b); 1348 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1349 proto_len = 256 * ucp[6] + ucp[7]; 1350 data_len = 256 * ucp[8] + ucp[9]; 1351 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1352 proto_len = ucp[6] + 256 * ucp[7]; 1353 data_len = ucp[8] + 256 * ucp[9]; 1354 } else { 1355 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1356 ucp[0]); 1357 return -1; 1358 } 1359 1360 /* Check if the whole packet is in buffer. */ 1361 if (sshbuf_len(b) < 1362 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1363 return 0; 1364 1365 /* Check if authentication protocol matches. */ 1366 if (proto_len != strlen(sc->x11_saved_proto) || 1367 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1368 debug2("X11 connection uses different authentication protocol."); 1369 return -1; 1370 } 1371 /* Check if authentication data matches our fake data. */ 1372 if (data_len != sc->x11_fake_data_len || 1373 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1374 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1375 debug2("X11 auth data does not match fake data."); 1376 return -1; 1377 } 1378 /* Check fake data length */ 1379 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1380 error("X11 fake_data_len %d != saved_data_len %d", 1381 sc->x11_fake_data_len, sc->x11_saved_data_len); 1382 return -1; 1383 } 1384 /* 1385 * Received authentication protocol and data match 1386 * our fake data. Substitute the fake data with real 1387 * data. 1388 */ 1389 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1390 sc->x11_saved_data, sc->x11_saved_data_len); 1391 return 1; 1392 } 1393 1394 void 1395 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1396 { 1397 debug3_f("channel %d: forcibly closing", c->self); 1398 if (c->istate == CHAN_INPUT_OPEN) 1399 chan_read_failed(ssh, c); 1400 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1401 sshbuf_reset(c->input); 1402 chan_ibuf_empty(ssh, c); 1403 } 1404 if (c->ostate == CHAN_OUTPUT_OPEN || 1405 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1406 sshbuf_reset(c->output); 1407 chan_write_failed(ssh, c); 1408 } 1409 if (c->detach_user) 1410 c->detach_user(ssh, c->self, 1, NULL); 1411 if (c->efd != -1) 1412 channel_close_fd(ssh, c, &c->efd); 1413 if (abandon) 1414 c->type = SSH_CHANNEL_ABANDONED; 1415 /* exempt from inactivity timeouts */ 1416 c->inactive_deadline = 0; 1417 c->lastused = 0; 1418 } 1419 1420 static void 1421 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1422 { 1423 int ret = x11_open_helper(ssh, c->output); 1424 1425 /* c->force_drain = 1; */ 1426 1427 if (ret == 1) { 1428 c->type = SSH_CHANNEL_OPEN; 1429 channel_set_used_time(ssh, c); 1430 channel_pre_open(ssh, c); 1431 } else if (ret == -1) { 1432 logit("X11 connection rejected because of wrong " 1433 "authentication."); 1434 debug2("X11 rejected %d i%d/o%d", 1435 c->self, c->istate, c->ostate); 1436 channel_force_close(ssh, c, 0); 1437 } 1438 } 1439 1440 static void 1441 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1442 { 1443 c->io_want = 0; 1444 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1445 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1446 c->io_want |= SSH_CHAN_IO_RFD; 1447 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1448 /* clear buffer immediately (discard any partial packet) */ 1449 sshbuf_reset(c->input); 1450 chan_ibuf_empty(ssh, c); 1451 /* Start output drain. XXX just kill chan? */ 1452 chan_rcvd_oclose(ssh, c); 1453 } 1454 if (c->ostate == CHAN_OUTPUT_OPEN || 1455 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1456 if (sshbuf_len(c->output) > 0) 1457 c->io_want |= SSH_CHAN_IO_WFD; 1458 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1459 chan_obuf_empty(ssh, c); 1460 } 1461 } 1462 1463 /* try to decode a socks4 header */ 1464 static int 1465 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1466 { 1467 const char *p; 1468 char *host; 1469 u_int len, have, i, found, need; 1470 char username[256]; 1471 struct { 1472 u_int8_t version; 1473 u_int8_t command; 1474 u_int16_t dest_port; 1475 struct in_addr dest_addr; 1476 } s4_req, s4_rsp; 1477 int r; 1478 1479 debug2("channel %d: decode socks4", c->self); 1480 1481 have = sshbuf_len(input); 1482 len = sizeof(s4_req); 1483 if (have < len) 1484 return 0; 1485 p = (const char *)sshbuf_ptr(input); 1486 1487 need = 1; 1488 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1489 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1490 debug2("channel %d: socks4a request", c->self); 1491 /* ... and needs an extra string (the hostname) */ 1492 need = 2; 1493 } 1494 /* Check for terminating NUL on the string(s) */ 1495 for (found = 0, i = len; i < have; i++) { 1496 if (p[i] == '\0') { 1497 found++; 1498 if (found == need) 1499 break; 1500 } 1501 if (i > 1024) { 1502 /* the peer is probably sending garbage */ 1503 debug("channel %d: decode socks4: too long", 1504 c->self); 1505 return -1; 1506 } 1507 } 1508 if (found < need) 1509 return 0; 1510 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1511 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1512 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1513 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1514 debug_r(r, "channels %d: decode socks4", c->self); 1515 return -1; 1516 } 1517 have = sshbuf_len(input); 1518 p = (const char *)sshbuf_ptr(input); 1519 if (memchr(p, '\0', have) == NULL) { 1520 error("channel %d: decode socks4: unterminated user", c->self); 1521 return -1; 1522 } 1523 len = strlen(p); 1524 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1525 len++; /* trailing '\0' */ 1526 strlcpy(username, p, sizeof(username)); 1527 if ((r = sshbuf_consume(input, len)) != 0) 1528 fatal_fr(r, "channel %d: consume", c->self); 1529 free(c->path); 1530 c->path = NULL; 1531 if (need == 1) { /* SOCKS4: one string */ 1532 host = inet_ntoa(s4_req.dest_addr); 1533 c->path = xstrdup(host); 1534 } else { /* SOCKS4A: two strings */ 1535 have = sshbuf_len(input); 1536 p = (const char *)sshbuf_ptr(input); 1537 if (memchr(p, '\0', have) == NULL) { 1538 error("channel %d: decode socks4a: host not nul " 1539 "terminated", c->self); 1540 return -1; 1541 } 1542 len = strlen(p); 1543 debug2("channel %d: decode socks4a: host %s/%d", 1544 c->self, p, len); 1545 len++; /* trailing '\0' */ 1546 if (len > NI_MAXHOST) { 1547 error("channel %d: hostname \"%.100s\" too long", 1548 c->self, p); 1549 return -1; 1550 } 1551 c->path = xstrdup(p); 1552 if ((r = sshbuf_consume(input, len)) != 0) 1553 fatal_fr(r, "channel %d: consume", c->self); 1554 } 1555 c->host_port = ntohs(s4_req.dest_port); 1556 1557 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1558 c->self, c->path, c->host_port, s4_req.command); 1559 1560 if (s4_req.command != 1) { 1561 debug("channel %d: cannot handle: %s cn %d", 1562 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1563 return -1; 1564 } 1565 s4_rsp.version = 0; /* vn: 0 for reply */ 1566 s4_rsp.command = 90; /* cd: req granted */ 1567 s4_rsp.dest_port = 0; /* ignored */ 1568 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1569 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1570 fatal_fr(r, "channel %d: append reply", c->self); 1571 return 1; 1572 } 1573 1574 /* try to decode a socks5 header */ 1575 #define SSH_SOCKS5_AUTHDONE 0x1000 1576 #define SSH_SOCKS5_NOAUTH 0x00 1577 #define SSH_SOCKS5_IPV4 0x01 1578 #define SSH_SOCKS5_DOMAIN 0x03 1579 #define SSH_SOCKS5_IPV6 0x04 1580 #define SSH_SOCKS5_CONNECT 0x01 1581 #define SSH_SOCKS5_SUCCESS 0x00 1582 1583 static int 1584 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1585 { 1586 /* XXX use get/put_u8 instead of trusting struct padding */ 1587 struct { 1588 u_int8_t version; 1589 u_int8_t command; 1590 u_int8_t reserved; 1591 u_int8_t atyp; 1592 } s5_req, s5_rsp; 1593 u_int16_t dest_port; 1594 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1595 const u_char *p; 1596 u_int have, need, i, found, nmethods, addrlen, af; 1597 int r; 1598 1599 debug2("channel %d: decode socks5", c->self); 1600 p = sshbuf_ptr(input); 1601 if (p[0] != 0x05) 1602 return -1; 1603 have = sshbuf_len(input); 1604 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1605 /* format: ver | nmethods | methods */ 1606 if (have < 2) 1607 return 0; 1608 nmethods = p[1]; 1609 if (have < nmethods + 2) 1610 return 0; 1611 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1612 for (found = 0, i = 2; i < nmethods + 2; i++) { 1613 if (p[i] == SSH_SOCKS5_NOAUTH) { 1614 found = 1; 1615 break; 1616 } 1617 } 1618 if (!found) { 1619 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1620 c->self); 1621 return -1; 1622 } 1623 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1624 fatal_fr(r, "channel %d: consume", c->self); 1625 /* version, method */ 1626 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1627 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1628 fatal_fr(r, "channel %d: append reply", c->self); 1629 c->flags |= SSH_SOCKS5_AUTHDONE; 1630 debug2("channel %d: socks5 auth done", c->self); 1631 return 0; /* need more */ 1632 } 1633 debug2("channel %d: socks5 post auth", c->self); 1634 if (have < sizeof(s5_req)+1) 1635 return 0; /* need more */ 1636 memcpy(&s5_req, p, sizeof(s5_req)); 1637 if (s5_req.version != 0x05 || 1638 s5_req.command != SSH_SOCKS5_CONNECT || 1639 s5_req.reserved != 0x00) { 1640 debug2("channel %d: only socks5 connect supported", c->self); 1641 return -1; 1642 } 1643 switch (s5_req.atyp){ 1644 case SSH_SOCKS5_IPV4: 1645 addrlen = 4; 1646 af = AF_INET; 1647 break; 1648 case SSH_SOCKS5_DOMAIN: 1649 addrlen = p[sizeof(s5_req)]; 1650 af = -1; 1651 break; 1652 case SSH_SOCKS5_IPV6: 1653 addrlen = 16; 1654 af = AF_INET6; 1655 break; 1656 default: 1657 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1658 return -1; 1659 } 1660 need = sizeof(s5_req) + addrlen + 2; 1661 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1662 need++; 1663 if (have < need) 1664 return 0; 1665 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1666 fatal_fr(r, "channel %d: consume", c->self); 1667 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1668 /* host string length */ 1669 if ((r = sshbuf_consume(input, 1)) != 0) 1670 fatal_fr(r, "channel %d: consume", c->self); 1671 } 1672 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1673 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1674 debug_r(r, "channel %d: parse addr/port", c->self); 1675 return -1; 1676 } 1677 dest_addr[addrlen] = '\0'; 1678 free(c->path); 1679 c->path = NULL; 1680 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1681 if (addrlen >= NI_MAXHOST) { 1682 error("channel %d: dynamic request: socks5 hostname " 1683 "\"%.100s\" too long", c->self, dest_addr); 1684 return -1; 1685 } 1686 c->path = xstrdup(dest_addr); 1687 } else { 1688 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1689 return -1; 1690 c->path = xstrdup(ntop); 1691 } 1692 c->host_port = ntohs(dest_port); 1693 1694 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1695 c->self, c->path, c->host_port, s5_req.command); 1696 1697 s5_rsp.version = 0x05; 1698 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1699 s5_rsp.reserved = 0; /* ignored */ 1700 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1701 dest_port = 0; /* ignored */ 1702 1703 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1704 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1705 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1706 fatal_fr(r, "channel %d: append reply", c->self); 1707 return 1; 1708 } 1709 1710 Channel * 1711 channel_connect_stdio_fwd(struct ssh *ssh, 1712 const char *host_to_connect, int port_to_connect, 1713 int in, int out, int nonblock) 1714 { 1715 Channel *c; 1716 1717 debug_f("%s:%d", host_to_connect, port_to_connect); 1718 1719 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1720 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1721 0, "stdio-forward", nonblock); 1722 1723 c->path = xstrdup(host_to_connect); 1724 c->host_port = port_to_connect; 1725 c->listening_port = 0; 1726 c->force_drain = 1; 1727 1728 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1729 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1730 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1731 1732 return c; 1733 } 1734 1735 /* dynamic port forwarding */ 1736 static void 1737 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1738 { 1739 const u_char *p; 1740 u_int have; 1741 int ret; 1742 1743 c->io_want = 0; 1744 have = sshbuf_len(c->input); 1745 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1746 /* sshbuf_dump(c->input, stderr); */ 1747 /* check if the fixed size part of the packet is in buffer. */ 1748 if (have < 3) { 1749 /* need more */ 1750 c->io_want |= SSH_CHAN_IO_RFD; 1751 return; 1752 } 1753 /* try to guess the protocol */ 1754 p = sshbuf_ptr(c->input); 1755 /* XXX sshbuf_peek_u8? */ 1756 switch (p[0]) { 1757 case 0x04: 1758 ret = channel_decode_socks4(c, c->input, c->output); 1759 break; 1760 case 0x05: 1761 ret = channel_decode_socks5(c, c->input, c->output); 1762 break; 1763 default: 1764 ret = -1; 1765 break; 1766 } 1767 if (ret < 0) { 1768 chan_mark_dead(ssh, c); 1769 } else if (ret == 0) { 1770 debug2("channel %d: pre_dynamic: need more", c->self); 1771 /* need more */ 1772 c->io_want |= SSH_CHAN_IO_RFD; 1773 if (sshbuf_len(c->output)) 1774 c->io_want |= SSH_CHAN_IO_WFD; 1775 } else { 1776 /* switch to the next state */ 1777 c->type = SSH_CHANNEL_OPENING; 1778 port_open_helper(ssh, c, "direct-tcpip"); 1779 } 1780 } 1781 1782 /* simulate read-error */ 1783 static void 1784 rdynamic_close(struct ssh *ssh, Channel *c) 1785 { 1786 c->type = SSH_CHANNEL_OPEN; 1787 channel_force_close(ssh, c, 0); 1788 } 1789 1790 /* reverse dynamic port forwarding */ 1791 static void 1792 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1793 { 1794 const u_char *p; 1795 u_int have, len; 1796 int r, ret; 1797 1798 have = sshbuf_len(c->output); 1799 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1800 /* sshbuf_dump(c->output, stderr); */ 1801 /* EOF received */ 1802 if (c->flags & CHAN_EOF_RCVD) { 1803 if ((r = sshbuf_consume(c->output, have)) != 0) 1804 fatal_fr(r, "channel %d: consume", c->self); 1805 rdynamic_close(ssh, c); 1806 return; 1807 } 1808 /* check if the fixed size part of the packet is in buffer. */ 1809 if (have < 3) 1810 return; 1811 /* try to guess the protocol */ 1812 p = sshbuf_ptr(c->output); 1813 switch (p[0]) { 1814 case 0x04: 1815 /* switch input/output for reverse forwarding */ 1816 ret = channel_decode_socks4(c, c->output, c->input); 1817 break; 1818 case 0x05: 1819 ret = channel_decode_socks5(c, c->output, c->input); 1820 break; 1821 default: 1822 ret = -1; 1823 break; 1824 } 1825 if (ret < 0) { 1826 rdynamic_close(ssh, c); 1827 } else if (ret == 0) { 1828 debug2("channel %d: pre_rdynamic: need more", c->self); 1829 /* send socks request to peer */ 1830 len = sshbuf_len(c->input); 1831 if (len > 0 && len < c->remote_window) { 1832 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1833 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1834 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1835 (r = sshpkt_send(ssh)) != 0) { 1836 fatal_fr(r, "channel %i: rdynamic", c->self); 1837 } 1838 if ((r = sshbuf_consume(c->input, len)) != 0) 1839 fatal_fr(r, "channel %d: consume", c->self); 1840 c->remote_window -= len; 1841 } 1842 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1843 /* the connect failed */ 1844 rdynamic_close(ssh, c); 1845 } 1846 } 1847 1848 /* This is our fake X11 server socket. */ 1849 static void 1850 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1851 { 1852 Channel *nc; 1853 struct sockaddr_storage addr; 1854 int r, newsock, oerrno, remote_port; 1855 socklen_t addrlen; 1856 char buf[16384], *remote_ipaddr; 1857 1858 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1859 return; 1860 1861 debug("X11 connection requested."); 1862 addrlen = sizeof(addr); 1863 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1864 if (c->single_connection) { 1865 oerrno = errno; 1866 debug2("single_connection: closing X11 listener."); 1867 channel_close_fd(ssh, c, &c->sock); 1868 chan_mark_dead(ssh, c); 1869 errno = oerrno; 1870 } 1871 if (newsock == -1) { 1872 if (errno != EINTR && errno != EWOULDBLOCK && 1873 errno != ECONNABORTED) 1874 error("accept: %.100s", strerror(errno)); 1875 if (errno == EMFILE || errno == ENFILE) 1876 c->notbefore = monotime() + 1; 1877 return; 1878 } 1879 set_nodelay(newsock); 1880 remote_ipaddr = get_peer_ipaddr(newsock); 1881 remote_port = get_peer_port(newsock); 1882 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1883 remote_ipaddr, remote_port); 1884 1885 nc = channel_new(ssh, "x11-connection", 1886 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1887 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1888 open_preamble(ssh, __func__, nc, "x11"); 1889 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1890 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1891 fatal_fr(r, "channel %i: reply", c->self); 1892 } 1893 if ((r = sshpkt_send(ssh)) != 0) 1894 fatal_fr(r, "channel %i: send", c->self); 1895 free(remote_ipaddr); 1896 } 1897 1898 static void 1899 port_open_helper(struct ssh *ssh, Channel *c, const char *rtype) 1900 { 1901 char *local_ipaddr = get_local_ipaddr(c->sock); 1902 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1903 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1904 int remote_port = get_peer_port(c->sock); 1905 int r; 1906 1907 if (remote_port == -1) { 1908 /* Fake addr/port to appease peers that validate it (Tectia) */ 1909 free(remote_ipaddr); 1910 remote_ipaddr = xstrdup("127.0.0.1"); 1911 remote_port = 65535; 1912 } 1913 1914 free(c->remote_name); 1915 xasprintf(&c->remote_name, 1916 "%s: listening port %d for %.100s port %d, " 1917 "connect from %.200s port %d to %.100s port %d", 1918 rtype, c->listening_port, c->path, c->host_port, 1919 remote_ipaddr, remote_port, local_ipaddr, local_port); 1920 1921 open_preamble(ssh, __func__, c, rtype); 1922 if (strcmp(rtype, "direct-tcpip") == 0) { 1923 /* target host, port */ 1924 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1925 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1926 fatal_fr(r, "channel %i: reply", c->self); 1927 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1928 /* target path */ 1929 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1930 fatal_fr(r, "channel %i: reply", c->self); 1931 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1932 /* listen path */ 1933 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1934 fatal_fr(r, "channel %i: reply", c->self); 1935 } else { 1936 /* listen address, port */ 1937 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1938 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1939 fatal_fr(r, "channel %i: reply", c->self); 1940 } 1941 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1942 /* reserved for future owner/mode info */ 1943 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1944 fatal_fr(r, "channel %i: reply", c->self); 1945 } else { 1946 /* originator host and port */ 1947 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1948 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1949 fatal_fr(r, "channel %i: reply", c->self); 1950 } 1951 if ((r = sshpkt_send(ssh)) != 0) 1952 fatal_fr(r, "channel %i: send", c->self); 1953 free(remote_ipaddr); 1954 free(local_ipaddr); 1955 } 1956 1957 void 1958 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1959 { 1960 ssh->chanctxt->x11_refuse_time = refuse_time; 1961 } 1962 1963 /* 1964 * This socket is listening for connections to a forwarded TCP/IP port. 1965 */ 1966 static void 1967 channel_post_port_listener(struct ssh *ssh, Channel *c) 1968 { 1969 Channel *nc; 1970 struct sockaddr_storage addr; 1971 int newsock, nextstate; 1972 socklen_t addrlen; 1973 const char *rtype; 1974 1975 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1976 return; 1977 1978 debug("Connection to port %d forwarding to %.100s port %d requested.", 1979 c->listening_port, c->path, c->host_port); 1980 1981 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1982 nextstate = SSH_CHANNEL_OPENING; 1983 rtype = "forwarded-tcpip"; 1984 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1985 nextstate = SSH_CHANNEL_OPENING; 1986 rtype = "forwarded-streamlocal@openssh.com"; 1987 } else if (c->host_port == PORT_STREAMLOCAL) { 1988 nextstate = SSH_CHANNEL_OPENING; 1989 rtype = "direct-streamlocal@openssh.com"; 1990 } else if (c->host_port == 0) { 1991 nextstate = SSH_CHANNEL_DYNAMIC; 1992 rtype = "dynamic-tcpip"; 1993 } else { 1994 nextstate = SSH_CHANNEL_OPENING; 1995 rtype = "direct-tcpip"; 1996 } 1997 1998 addrlen = sizeof(addr); 1999 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2000 if (newsock == -1) { 2001 if (errno != EINTR && errno != EWOULDBLOCK && 2002 errno != ECONNABORTED) 2003 error("accept: %.100s", strerror(errno)); 2004 if (errno == EMFILE || errno == ENFILE) 2005 c->notbefore = monotime() + 1; 2006 return; 2007 } 2008 if (c->host_port != PORT_STREAMLOCAL) 2009 set_nodelay(newsock); 2010 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 2011 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 2012 nc->listening_port = c->listening_port; 2013 nc->host_port = c->host_port; 2014 if (c->path != NULL) 2015 nc->path = xstrdup(c->path); 2016 2017 if (nextstate != SSH_CHANNEL_DYNAMIC) 2018 port_open_helper(ssh, nc, rtype); 2019 } 2020 2021 /* 2022 * This is the authentication agent socket listening for connections from 2023 * clients. 2024 */ 2025 static void 2026 channel_post_auth_listener(struct ssh *ssh, Channel *c) 2027 { 2028 Channel *nc; 2029 int r, newsock; 2030 struct sockaddr_storage addr; 2031 socklen_t addrlen; 2032 2033 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2034 return; 2035 2036 addrlen = sizeof(addr); 2037 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2038 if (newsock == -1) { 2039 error("accept from auth socket: %.100s", strerror(errno)); 2040 if (errno == EMFILE || errno == ENFILE) 2041 c->notbefore = monotime() + 1; 2042 return; 2043 } 2044 nc = channel_new(ssh, "agent-connection", 2045 SSH_CHANNEL_OPENING, newsock, newsock, -1, 2046 c->local_window_max, c->local_maxpacket, 2047 0, "accepted auth socket", 1); 2048 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 2049 if ((r = sshpkt_send(ssh)) != 0) 2050 fatal_fr(r, "channel %i", c->self); 2051 } 2052 2053 static void 2054 channel_post_connecting(struct ssh *ssh, Channel *c) 2055 { 2056 int err = 0, sock, isopen, r; 2057 socklen_t sz = sizeof(err); 2058 2059 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2060 return; 2061 if (!c->have_remote_id) 2062 fatal_f("channel %d: no remote id", c->self); 2063 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2064 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2065 2066 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2067 err = errno; 2068 error("getsockopt SO_ERROR failed"); 2069 } 2070 2071 if (err == 0) { 2072 /* Non-blocking connection completed */ 2073 debug("channel %d: connected to %s port %d", 2074 c->self, c->connect_ctx.host, c->connect_ctx.port); 2075 channel_connect_ctx_free(&c->connect_ctx); 2076 c->type = SSH_CHANNEL_OPEN; 2077 channel_set_used_time(ssh, c); 2078 if (isopen) { 2079 /* no message necessary */ 2080 } else { 2081 if ((r = sshpkt_start(ssh, 2082 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2083 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2084 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2085 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2086 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2087 (r = sshpkt_send(ssh)) != 0) 2088 fatal_fr(r, "channel %i open confirm", c->self); 2089 } 2090 return; 2091 } 2092 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2093 return; 2094 2095 /* Non-blocking connection failed */ 2096 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2097 2098 /* Try next address, if any */ 2099 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2100 /* Exhausted all addresses for this destination */ 2101 error("connect_to %.100s port %d: failed.", 2102 c->connect_ctx.host, c->connect_ctx.port); 2103 channel_connect_ctx_free(&c->connect_ctx); 2104 if (isopen) { 2105 rdynamic_close(ssh, c); 2106 } else { 2107 if ((r = sshpkt_start(ssh, 2108 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2109 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2110 (r = sshpkt_put_u32(ssh, 2111 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2112 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2113 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2114 (r = sshpkt_send(ssh)) != 0) 2115 fatal_fr(r, "channel %i: failure", c->self); 2116 chan_mark_dead(ssh, c); 2117 } 2118 } 2119 2120 /* New non-blocking connection in progress */ 2121 close(c->sock); 2122 c->sock = c->rfd = c->wfd = sock; 2123 } 2124 2125 static int 2126 channel_handle_rfd(struct ssh *ssh, Channel *c) 2127 { 2128 char buf[CHAN_RBUF]; 2129 ssize_t len; 2130 int r; 2131 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2132 2133 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2134 return 1; /* Shouldn't happen */ 2135 if ((avail = sshbuf_avail(c->input)) == 0) 2136 return 1; /* Shouldn't happen */ 2137 2138 /* 2139 * For "simple" channels (i.e. not datagram or filtered), we can 2140 * read directly to the channel buffer. 2141 */ 2142 if (c->input_filter == NULL && !c->datagram) { 2143 /* Only OPEN channels have valid rwin */ 2144 if (c->type == SSH_CHANNEL_OPEN) { 2145 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2146 return 1; /* shouldn't happen */ 2147 if (maxlen > c->remote_window - have) 2148 maxlen = c->remote_window - have; 2149 } 2150 if (maxlen > avail) 2151 maxlen = avail; 2152 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2153 if (errno == EINTR || errno == EAGAIN) 2154 return 1; 2155 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2156 c->self, c->rfd, maxlen, ssh_err(r)); 2157 goto rfail; 2158 } 2159 if (nr != 0) 2160 channel_set_used_time(ssh, c); 2161 return 1; 2162 } 2163 2164 len = read(c->rfd, buf, sizeof(buf)); 2165 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2166 return 1; 2167 if (len <= 0) { 2168 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2169 c->self, c->rfd, len, 2170 len == 0 ? "closed" : strerror(errno)); 2171 rfail: 2172 if (c->type != SSH_CHANNEL_OPEN) { 2173 debug2("channel %d: not open", c->self); 2174 chan_mark_dead(ssh, c); 2175 return -1; 2176 } else { 2177 chan_read_failed(ssh, c); 2178 } 2179 return -1; 2180 } 2181 channel_set_used_time(ssh, c); 2182 if (c->input_filter != NULL) { 2183 if (c->input_filter(ssh, c, buf, len) == -1) { 2184 debug2("channel %d: filter stops", c->self); 2185 chan_read_failed(ssh, c); 2186 } 2187 } else if (c->datagram) { 2188 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2189 fatal_fr(r, "channel %i: put datagram", c->self); 2190 } 2191 return 1; 2192 } 2193 2194 static int 2195 channel_handle_wfd(struct ssh *ssh, Channel *c) 2196 { 2197 struct termios tio; 2198 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2199 size_t dlen, olen = 0; 2200 int r, len; 2201 2202 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2203 return 1; 2204 if (sshbuf_len(c->output) == 0) 2205 return 1; 2206 2207 /* Send buffered output data to the socket. */ 2208 olen = sshbuf_len(c->output); 2209 if (c->output_filter != NULL) { 2210 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2211 debug2("channel %d: filter stops", c->self); 2212 if (c->type != SSH_CHANNEL_OPEN) 2213 chan_mark_dead(ssh, c); 2214 else 2215 chan_write_failed(ssh, c); 2216 return -1; 2217 } 2218 } else if (c->datagram) { 2219 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2220 fatal_fr(r, "channel %i: get datagram", c->self); 2221 buf = data; 2222 } else { 2223 buf = data = sshbuf_mutable_ptr(c->output); 2224 dlen = sshbuf_len(c->output); 2225 } 2226 2227 if (c->datagram) { 2228 /* ignore truncated writes, datagrams might get lost */ 2229 len = write(c->wfd, buf, dlen); 2230 free(data); 2231 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2232 return 1; 2233 if (len <= 0) 2234 goto write_fail; 2235 goto out; 2236 } 2237 2238 len = write(c->wfd, buf, dlen); 2239 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2240 return 1; 2241 if (len <= 0) { 2242 write_fail: 2243 if (c->type != SSH_CHANNEL_OPEN) { 2244 debug2("channel %d: not open", c->self); 2245 chan_mark_dead(ssh, c); 2246 return -1; 2247 } else { 2248 chan_write_failed(ssh, c); 2249 } 2250 return -1; 2251 } 2252 channel_set_used_time(ssh, c); 2253 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2254 if (tcgetattr(c->wfd, &tio) == 0 && 2255 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2256 /* 2257 * Simulate echo to reduce the impact of 2258 * traffic analysis. We need to match the 2259 * size of a SSH2_MSG_CHANNEL_DATA message 2260 * (4 byte channel id + buf) 2261 */ 2262 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2263 (r = sshpkt_send(ssh)) != 0) 2264 fatal_fr(r, "channel %i: ignore", c->self); 2265 } 2266 } 2267 if ((r = sshbuf_consume(c->output, len)) != 0) 2268 fatal_fr(r, "channel %i: consume", c->self); 2269 out: 2270 c->local_consumed += olen - sshbuf_len(c->output); 2271 2272 return 1; 2273 } 2274 2275 static int 2276 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2277 { 2278 int r; 2279 ssize_t len; 2280 2281 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2282 return 1; 2283 if (sshbuf_len(c->extended) == 0) 2284 return 1; 2285 2286 len = write(c->efd, sshbuf_ptr(c->extended), 2287 sshbuf_len(c->extended)); 2288 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2289 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2290 return 1; 2291 if (len <= 0) { 2292 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2293 channel_close_fd(ssh, c, &c->efd); 2294 } else { 2295 if ((r = sshbuf_consume(c->extended, len)) != 0) 2296 fatal_fr(r, "channel %i: consume", c->self); 2297 c->local_consumed += len; 2298 channel_set_used_time(ssh, c); 2299 } 2300 return 1; 2301 } 2302 2303 static int 2304 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2305 { 2306 char buf[CHAN_RBUF]; 2307 int r; 2308 ssize_t len; 2309 2310 if ((c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2311 return 1; 2312 2313 len = read(c->efd, buf, sizeof(buf)); 2314 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2315 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2316 return 1; 2317 if (len <= 0) { 2318 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2319 channel_close_fd(ssh, c, &c->efd); 2320 return 1; 2321 } 2322 channel_set_used_time(ssh, c); 2323 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2324 debug3("channel %d: discard efd", c->self); 2325 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2326 fatal_fr(r, "channel %i: append", c->self); 2327 return 1; 2328 } 2329 2330 static int 2331 channel_handle_efd(struct ssh *ssh, Channel *c) 2332 { 2333 if (c->efd == -1) 2334 return 1; 2335 2336 /** XXX handle drain efd, too */ 2337 2338 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2339 return channel_handle_efd_write(ssh, c); 2340 else if (c->extended_usage == CHAN_EXTENDED_READ || 2341 c->extended_usage == CHAN_EXTENDED_IGNORE) 2342 return channel_handle_efd_read(ssh, c); 2343 2344 return 1; 2345 } 2346 2347 static int 2348 channel_check_window(struct ssh *ssh, Channel *c) 2349 { 2350 int r; 2351 2352 if (c->type == SSH_CHANNEL_OPEN && 2353 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2354 ((c->local_window_max - c->local_window > 2355 c->local_maxpacket*3) || 2356 c->local_window < c->local_window_max/2) && 2357 c->local_consumed > 0) { 2358 u_int addition = 0; 2359 u_int32_t tcpwinsz = channel_tcpwinsz(ssh); 2360 /* adjust max window size if we are in a dynamic environment */ 2361 if (c->dynamic_window && (tcpwinsz > c->local_window_max)) { 2362 /* grow the window somewhat aggressively to maintain 2363 * pressure */ 2364 addition = 1.5*(tcpwinsz - c->local_window_max); 2365 c->local_window_max += addition; 2366 debug("Channel: Window growth to %d by %d bytes", c->local_window_max, addition); 2367 } 2368 if (!c->have_remote_id) 2369 fatal_f("channel %d: no remote id", c->self); 2370 if ((r = sshpkt_start(ssh, 2371 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2372 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2373 (r = sshpkt_put_u32(ssh, c->local_consumed + addition)) != 0 || 2374 (r = sshpkt_send(ssh)) != 0) { 2375 fatal_fr(r, "channel %i", c->self); 2376 } 2377 debug2("channel %d: window %d sent adjust %d", c->self, 2378 c->local_window, 2379 c->local_consumed + addition); 2380 c->local_window += c->local_consumed + addition; 2381 c->local_consumed = 0; 2382 } 2383 return 1; 2384 } 2385 2386 static void 2387 channel_post_open(struct ssh *ssh, Channel *c) 2388 { 2389 channel_handle_rfd(ssh, c); 2390 channel_handle_wfd(ssh, c); 2391 channel_handle_efd(ssh, c); 2392 channel_check_window(ssh, c); 2393 } 2394 2395 static u_int 2396 read_mux(struct ssh *ssh, Channel *c, u_int need) 2397 { 2398 char buf[CHAN_RBUF]; 2399 ssize_t len; 2400 u_int rlen; 2401 int r; 2402 2403 if (sshbuf_len(c->input) < need) { 2404 rlen = need - sshbuf_len(c->input); 2405 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2406 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2407 return sshbuf_len(c->input); 2408 if (len <= 0) { 2409 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2410 c->self, c->rfd, len); 2411 chan_read_failed(ssh, c); 2412 return 0; 2413 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2414 fatal_fr(r, "channel %i: append", c->self); 2415 } 2416 return sshbuf_len(c->input); 2417 } 2418 2419 static void 2420 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2421 { 2422 u_int need; 2423 2424 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2425 return; 2426 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2427 return; 2428 if (c->mux_pause) 2429 return; 2430 2431 /* 2432 * Don't not read past the precise end of packets to 2433 * avoid disrupting fd passing. 2434 */ 2435 if (read_mux(ssh, c, 4) < 4) /* read header */ 2436 return; 2437 /* XXX sshbuf_peek_u32 */ 2438 need = PEEK_U32(sshbuf_ptr(c->input)); 2439 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2440 if (need > CHANNEL_MUX_MAX_PACKET) { 2441 debug2("channel %d: packet too big %u > %u", 2442 c->self, CHANNEL_MUX_MAX_PACKET, need); 2443 chan_rcvd_oclose(ssh, c); 2444 return; 2445 } 2446 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2447 return; 2448 if (c->mux_rcb(ssh, c) != 0) { 2449 debug("channel %d: mux_rcb failed", c->self); 2450 chan_mark_dead(ssh, c); 2451 return; 2452 } 2453 } 2454 2455 static void 2456 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2457 { 2458 ssize_t len; 2459 int r; 2460 2461 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2462 return; 2463 if (sshbuf_len(c->output) == 0) 2464 return; 2465 2466 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2467 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2468 return; 2469 if (len <= 0) { 2470 chan_mark_dead(ssh, c); 2471 return; 2472 } 2473 if ((r = sshbuf_consume(c->output, len)) != 0) 2474 fatal_fr(r, "channel %i: consume", c->self); 2475 } 2476 2477 static void 2478 channel_post_mux_client(struct ssh *ssh, Channel *c) 2479 { 2480 channel_post_mux_client_read(ssh, c); 2481 channel_post_mux_client_write(ssh, c); 2482 } 2483 2484 static void 2485 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2486 { 2487 Channel *nc; 2488 struct sockaddr_storage addr; 2489 socklen_t addrlen; 2490 int newsock; 2491 uid_t euid; 2492 gid_t egid; 2493 2494 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2495 return; 2496 2497 debug("multiplexing control connection"); 2498 2499 /* 2500 * Accept connection on control socket 2501 */ 2502 memset(&addr, 0, sizeof(addr)); 2503 addrlen = sizeof(addr); 2504 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2505 &addrlen)) == -1) { 2506 error_f("accept: %s", strerror(errno)); 2507 if (errno == EMFILE || errno == ENFILE) 2508 c->notbefore = monotime() + 1; 2509 return; 2510 } 2511 2512 if (getpeereid(newsock, &euid, &egid) == -1) { 2513 error_f("getpeereid failed: %s", strerror(errno)); 2514 close(newsock); 2515 return; 2516 } 2517 if ((euid != 0) && (getuid() != euid)) { 2518 error("multiplex uid mismatch: peer euid %u != uid %u", 2519 (u_int)euid, (u_int)getuid()); 2520 close(newsock); 2521 return; 2522 } 2523 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2524 newsock, newsock, -1, c->local_window_max, 2525 c->local_maxpacket, 0, "mux-control", 1); 2526 nc->mux_rcb = c->mux_rcb; 2527 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2528 /* establish state */ 2529 nc->mux_rcb(ssh, nc); 2530 /* mux state transitions must not elicit protocol messages */ 2531 nc->flags |= CHAN_LOCAL; 2532 } 2533 2534 static void 2535 channel_handler_init(struct ssh_channels *sc) 2536 { 2537 chan_fn **pre, **post; 2538 2539 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2540 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2541 fatal_f("allocation failed"); 2542 2543 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2544 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2545 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2546 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2547 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2548 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2549 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2550 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2551 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2552 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2553 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2554 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2555 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2556 2557 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2558 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2559 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2560 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2561 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2562 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2563 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2564 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2565 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2566 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2567 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2568 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2569 2570 sc->channel_pre = pre; 2571 sc->channel_post = post; 2572 } 2573 2574 /* gc dead channels */ 2575 static void 2576 channel_garbage_collect(struct ssh *ssh, Channel *c) 2577 { 2578 if (c == NULL) 2579 return; 2580 if (c->detach_user != NULL) { 2581 if (!chan_is_dead(ssh, c, c->detach_close)) 2582 return; 2583 2584 debug2("channel %d: gc: notify user", c->self); 2585 c->detach_user(ssh, c->self, 0, NULL); 2586 /* if we still have a callback */ 2587 if (c->detach_user != NULL) 2588 return; 2589 debug2("channel %d: gc: user detached", c->self); 2590 } 2591 if (!chan_is_dead(ssh, c, 1)) 2592 return; 2593 debug2("channel %d: garbage collecting", c->self); 2594 channel_free(ssh, c); 2595 } 2596 2597 enum channel_table { CHAN_PRE, CHAN_POST }; 2598 2599 static void 2600 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2601 { 2602 struct ssh_channels *sc = ssh->chanctxt; 2603 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2604 u_int i, oalloc; 2605 Channel *c; 2606 time_t now; 2607 2608 now = monotime(); 2609 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2610 c = sc->channels[i]; 2611 if (c == NULL) 2612 continue; 2613 /* Try to keep IO going while rekeying */ 2614 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2615 continue; 2616 if (c->delayed) { 2617 if (table == CHAN_PRE) 2618 c->delayed = 0; 2619 else 2620 continue; 2621 } 2622 if (ftab[c->type] != NULL) { 2623 if (table == CHAN_PRE && c->type == SSH_CHANNEL_OPEN && 2624 channel_get_expiry(ssh, c) != 0 && 2625 now >= channel_get_expiry(ssh, c)) { 2626 /* channel closed for inactivity */ 2627 verbose("channel %d: closing after %u seconds " 2628 "of inactivity", c->self, 2629 c->inactive_deadline); 2630 channel_force_close(ssh, c, 1); 2631 } else if (c->notbefore <= now) { 2632 /* Run handlers that are not paused. */ 2633 (*ftab[c->type])(ssh, c); 2634 /* inactivity timeouts must interrupt poll() */ 2635 if (timeout != NULL && 2636 c->type == SSH_CHANNEL_OPEN && 2637 channel_get_expiry(ssh, c) != 0) { 2638 ptimeout_deadline_monotime(timeout, 2639 channel_get_expiry(ssh, c)); 2640 } 2641 } else if (timeout != NULL) { 2642 /* 2643 * Arrange for poll() wakeup when channel pause 2644 * timer expires. 2645 */ 2646 ptimeout_deadline_monotime(timeout, 2647 c->notbefore); 2648 } 2649 } 2650 channel_garbage_collect(ssh, c); 2651 } 2652 } 2653 2654 /* 2655 * Create sockets before preparing IO. 2656 * This is necessary for things that need to happen after reading 2657 * the network-input but need to be completed before IO event setup, e.g. 2658 * because they may create new channels. 2659 */ 2660 static void 2661 channel_before_prepare_io(struct ssh *ssh) 2662 { 2663 struct ssh_channels *sc = ssh->chanctxt; 2664 Channel *c; 2665 u_int i, oalloc; 2666 2667 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2668 c = sc->channels[i]; 2669 if (c == NULL) 2670 continue; 2671 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2672 channel_before_prepare_io_rdynamic(ssh, c); 2673 } 2674 } 2675 2676 static void 2677 dump_channel_poll(const char *func, const char *what, Channel *c, 2678 u_int pollfd_offset, struct pollfd *pfd) 2679 { 2680 #ifdef DEBUG_CHANNEL_POLL 2681 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2682 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2683 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2684 c->rfd, c->wfd, c->efd, c->sock, 2685 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2686 c->io_want, c->io_ready, 2687 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2688 #endif 2689 } 2690 2691 /* Prepare pollfd entries for a single channel */ 2692 static void 2693 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2694 struct pollfd *pfd, u_int npfd) 2695 { 2696 u_int ev, p = *next_pollfd; 2697 2698 if (c == NULL) 2699 return; 2700 if (p + 4 > npfd) { 2701 /* Shouldn't happen */ 2702 fatal_f("channel %d: bad pfd offset %u (max %u)", 2703 c->self, p, npfd); 2704 } 2705 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2706 /* 2707 * prepare c->rfd 2708 * 2709 * This is a special case, since c->rfd might be the same as 2710 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2711 * IO too. 2712 */ 2713 if (c->rfd != -1) { 2714 ev = 0; 2715 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2716 ev |= POLLIN; 2717 /* rfd == wfd */ 2718 if (c->wfd == c->rfd) { 2719 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2720 ev |= POLLOUT; 2721 } 2722 /* rfd == efd */ 2723 if (c->efd == c->rfd) { 2724 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2725 ev |= POLLIN; 2726 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2727 ev |= POLLOUT; 2728 } 2729 /* rfd == sock */ 2730 if (c->sock == c->rfd) { 2731 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2732 ev |= POLLIN; 2733 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2734 ev |= POLLOUT; 2735 } 2736 /* Pack a pfd entry if any event armed for this fd */ 2737 if (ev != 0) { 2738 c->pfds[0] = p; 2739 pfd[p].fd = c->rfd; 2740 pfd[p].events = ev; 2741 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2742 p++; 2743 } 2744 } 2745 /* prepare c->wfd if wanting IO and not already handled above */ 2746 if (c->wfd != -1 && c->rfd != c->wfd) { 2747 ev = 0; 2748 if ((c->io_want & SSH_CHAN_IO_WFD)) 2749 ev |= POLLOUT; 2750 /* Pack a pfd entry if any event armed for this fd */ 2751 if (ev != 0) { 2752 c->pfds[1] = p; 2753 pfd[p].fd = c->wfd; 2754 pfd[p].events = ev; 2755 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2756 p++; 2757 } 2758 } 2759 /* prepare c->efd if wanting IO and not already handled above */ 2760 if (c->efd != -1 && c->rfd != c->efd) { 2761 ev = 0; 2762 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2763 ev |= POLLIN; 2764 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2765 ev |= POLLOUT; 2766 /* Pack a pfd entry if any event armed for this fd */ 2767 if (ev != 0) { 2768 c->pfds[2] = p; 2769 pfd[p].fd = c->efd; 2770 pfd[p].events = ev; 2771 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2772 p++; 2773 } 2774 } 2775 /* prepare c->sock if wanting IO and not already handled above */ 2776 if (c->sock != -1 && c->rfd != c->sock) { 2777 ev = 0; 2778 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2779 ev |= POLLIN; 2780 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2781 ev |= POLLOUT; 2782 /* Pack a pfd entry if any event armed for this fd */ 2783 if (ev != 0) { 2784 c->pfds[3] = p; 2785 pfd[p].fd = c->sock; 2786 pfd[p].events = 0; 2787 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2788 p++; 2789 } 2790 } 2791 *next_pollfd = p; 2792 } 2793 2794 /* * Allocate/prepare poll structure */ 2795 void 2796 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2797 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2798 { 2799 struct ssh_channels *sc = ssh->chanctxt; 2800 u_int i, oalloc, p, npfd = npfd_reserved; 2801 2802 channel_before_prepare_io(ssh); /* might create a new channel */ 2803 /* clear out I/O flags from last poll */ 2804 for (i = 0; i < sc->channels_alloc; i++) { 2805 if (sc->channels[i] == NULL) 2806 continue; 2807 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2808 } 2809 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2810 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2811 fatal_f("too many channels"); /* shouldn't happen */ 2812 npfd += sc->channels_alloc * 4; 2813 if (npfd > *npfd_allocp) { 2814 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2815 npfd, sizeof(**pfdp)); 2816 *npfd_allocp = npfd; 2817 } 2818 *npfd_activep = npfd_reserved; 2819 oalloc = sc->channels_alloc; 2820 2821 channel_handler(ssh, CHAN_PRE, timeout); 2822 2823 if (oalloc != sc->channels_alloc) { 2824 /* shouldn't happen */ 2825 fatal_f("channels_alloc changed during CHAN_PRE " 2826 "(was %u, now %u)", oalloc, sc->channels_alloc); 2827 } 2828 2829 /* Prepare pollfd */ 2830 p = npfd_reserved; 2831 for (i = 0; i < sc->channels_alloc; i++) 2832 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2833 *npfd_activep = p; 2834 } 2835 2836 static void 2837 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2838 const char *what, u_int revents_mask, u_int ready) 2839 { 2840 struct pollfd *pfd = &pfds[p]; 2841 2842 if (fd == -1) 2843 return; 2844 if (p == -1 || (u_int)p >= npfd) 2845 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2846 dump_channel_poll(__func__, what, c, p, pfd); 2847 if (pfd->fd != fd) { 2848 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2849 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2850 c->rfd, c->wfd, c->efd, c->sock); 2851 } 2852 if ((pfd->revents & POLLNVAL) != 0) { 2853 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2854 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2855 } 2856 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2857 c->io_ready |= ready & c->io_want; 2858 } 2859 2860 /* 2861 * After poll, perform any appropriate operations for channels which have 2862 * events pending. 2863 */ 2864 void 2865 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2866 { 2867 struct ssh_channels *sc = ssh->chanctxt; 2868 u_int i; 2869 int p; 2870 Channel *c; 2871 2872 #ifdef DEBUG_CHANNEL_POLL 2873 for (p = 0; p < (int)npfd; p++) { 2874 if (pfd[p].revents == 0) 2875 continue; 2876 debug_f("pfd[%u].fd %d rev 0x%04x", 2877 p, pfd[p].fd, pfd[p].revents); 2878 } 2879 #endif 2880 2881 /* Convert pollfd into c->io_ready */ 2882 for (i = 0; i < sc->channels_alloc; i++) { 2883 c = sc->channels[i]; 2884 if (c == NULL) 2885 continue; 2886 /* if rfd is shared with efd/sock then wfd should be too */ 2887 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2888 (c->rfd == c->efd || c->rfd == c->sock)) { 2889 /* Shouldn't happen */ 2890 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2891 c->self, c->rfd, c->wfd, c->efd, c->sock); 2892 } 2893 c->io_ready = 0; 2894 /* rfd, potentially shared with wfd, efd and sock */ 2895 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2896 fd_ready(c, p, pfd, npfd, c->rfd, 2897 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2898 if (c->rfd == c->wfd) { 2899 fd_ready(c, p, pfd, npfd, c->wfd, 2900 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2901 } 2902 if (c->rfd == c->efd) { 2903 fd_ready(c, p, pfd, npfd, c->efd, 2904 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2905 fd_ready(c, p, pfd, npfd, c->efd, 2906 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2907 } 2908 if (c->rfd == c->sock) { 2909 fd_ready(c, p, pfd, npfd, c->sock, 2910 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2911 fd_ready(c, p, pfd, npfd, c->sock, 2912 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2913 } 2914 dump_channel_poll(__func__, "rfd", c, p, pfd); 2915 } 2916 /* wfd */ 2917 if (c->wfd != -1 && c->wfd != c->rfd && 2918 (p = c->pfds[1]) != -1) { 2919 fd_ready(c, p, pfd, npfd, c->wfd, 2920 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2921 dump_channel_poll(__func__, "wfd", c, p, pfd); 2922 } 2923 /* efd */ 2924 if (c->efd != -1 && c->efd != c->rfd && 2925 (p = c->pfds[2]) != -1) { 2926 fd_ready(c, p, pfd, npfd, c->efd, 2927 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2928 fd_ready(c, p, pfd, npfd, c->efd, 2929 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2930 dump_channel_poll(__func__, "efd", c, p, pfd); 2931 } 2932 /* sock */ 2933 if (c->sock != -1 && c->sock != c->rfd && 2934 (p = c->pfds[3]) != -1) { 2935 fd_ready(c, p, pfd, npfd, c->sock, 2936 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2937 fd_ready(c, p, pfd, npfd, c->sock, 2938 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2939 dump_channel_poll(__func__, "sock", c, p, pfd); 2940 } 2941 } 2942 channel_handler(ssh, CHAN_POST, NULL); 2943 } 2944 2945 /* 2946 * Enqueue data for channels with open or draining c->input. 2947 * Returns non-zero if a packet was enqueued. 2948 */ 2949 static int 2950 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2951 { 2952 size_t len, plen; 2953 const u_char *pkt; 2954 int r; 2955 2956 if ((len = sshbuf_len(c->input)) == 0) { 2957 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2958 /* 2959 * input-buffer is empty and read-socket shutdown: 2960 * tell peer, that we will not send more data: 2961 * send IEOF. 2962 * hack for extended data: delay EOF if EFD still 2963 * in use. 2964 */ 2965 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2966 debug2("channel %d: " 2967 "ibuf_empty delayed efd %d/(%zu)", 2968 c->self, c->efd, sshbuf_len(c->extended)); 2969 else 2970 chan_ibuf_empty(ssh, c); 2971 } 2972 return 0; 2973 } 2974 2975 if (!c->have_remote_id) 2976 fatal_f("channel %d: no remote id", c->self); 2977 2978 if (c->datagram) { 2979 /* Check datagram will fit; drop if not */ 2980 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2981 fatal_fr(r, "channel %i: get datagram", c->self); 2982 /* 2983 * XXX this does tail-drop on the datagram queue which is 2984 * usually suboptimal compared to head-drop. Better to have 2985 * backpressure at read time? (i.e. read + discard) 2986 */ 2987 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2988 debug("channel %d: datagram too big", c->self); 2989 return 0; 2990 } 2991 /* Enqueue it */ 2992 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2993 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2994 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2995 (r = sshpkt_send(ssh)) != 0) 2996 fatal_fr(r, "channel %i: send datagram", c->self); 2997 c->remote_window -= plen; 2998 return 1; 2999 } 3000 3001 /* Enqueue packet for buffered data. */ 3002 if (len > c->remote_window) 3003 len = c->remote_window; 3004 if (len > c->remote_maxpacket) 3005 len = c->remote_maxpacket; 3006 if (len == 0) 3007 return 0; 3008 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 3009 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3010 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 3011 (r = sshpkt_send(ssh)) != 0) 3012 fatal_fr(r, "channel %i: send data", c->self); 3013 if ((r = sshbuf_consume(c->input, len)) != 0) 3014 fatal_fr(r, "channel %i: consume", c->self); 3015 c->remote_window -= len; 3016 return 1; 3017 } 3018 3019 /* 3020 * Enqueue data for channels with open c->extended in read mode. 3021 * Returns non-zero if a packet was enqueued. 3022 */ 3023 static int 3024 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 3025 { 3026 size_t len; 3027 int r; 3028 3029 if ((len = sshbuf_len(c->extended)) == 0) 3030 return 0; 3031 3032 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 3033 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 3034 if (len > c->remote_window) 3035 len = c->remote_window; 3036 if (len > c->remote_maxpacket) 3037 len = c->remote_maxpacket; 3038 if (len == 0) 3039 return 0; 3040 if (!c->have_remote_id) 3041 fatal_f("channel %d: no remote id", c->self); 3042 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 3043 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3044 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 3045 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 3046 (r = sshpkt_send(ssh)) != 0) 3047 fatal_fr(r, "channel %i: data", c->self); 3048 if ((r = sshbuf_consume(c->extended, len)) != 0) 3049 fatal_fr(r, "channel %i: consume", c->self); 3050 c->remote_window -= len; 3051 debug2("channel %d: sent ext data %zu", c->self, len); 3052 return 1; 3053 } 3054 3055 /* 3056 * If there is data to send to the connection, enqueue some of it now. 3057 * Returns non-zero if data was enqueued. 3058 */ 3059 int 3060 channel_output_poll(struct ssh *ssh) 3061 { 3062 struct ssh_channels *sc = ssh->chanctxt; 3063 Channel *c; 3064 u_int i; 3065 int ret = 0; 3066 3067 for (i = 0; i < sc->channels_alloc; i++) { 3068 c = sc->channels[i]; 3069 if (c == NULL) 3070 continue; 3071 3072 /* 3073 * We are only interested in channels that can have buffered 3074 * incoming data. 3075 */ 3076 if (c->type != SSH_CHANNEL_OPEN) 3077 continue; 3078 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3079 /* XXX is this true? */ 3080 debug3("channel %d: will not send data after close", 3081 c->self); 3082 continue; 3083 } 3084 3085 /* Get the amount of buffered data for this channel. */ 3086 if (c->istate == CHAN_INPUT_OPEN || 3087 c->istate == CHAN_INPUT_WAIT_DRAIN) 3088 ret |= channel_output_poll_input_open(ssh, c); 3089 /* Send extended data, i.e. stderr */ 3090 if (!(c->flags & CHAN_EOF_SENT) && 3091 c->extended_usage == CHAN_EXTENDED_READ) 3092 ret |= channel_output_poll_extended_read(ssh, c); 3093 } 3094 return ret; 3095 } 3096 3097 /* -- mux proxy support */ 3098 3099 /* 3100 * When multiplexing channel messages for mux clients we have to deal 3101 * with downstream messages from the mux client and upstream messages 3102 * from the ssh server: 3103 * 1) Handling downstream messages is straightforward and happens 3104 * in channel_proxy_downstream(): 3105 * - We forward all messages (mostly) unmodified to the server. 3106 * - However, in order to route messages from upstream to the correct 3107 * downstream client, we have to replace the channel IDs used by the 3108 * mux clients with a unique channel ID because the mux clients might 3109 * use conflicting channel IDs. 3110 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3111 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3112 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3113 * with the newly allocated channel ID. 3114 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3115 * channels and processed by channel_proxy_upstream(). The local channel ID 3116 * is then translated back to the original mux client ID. 3117 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3118 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3119 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3120 * downstream mux client are removed. 3121 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3122 * requires more work, because they are not addressed to a specific 3123 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3124 * out whether the request is addressed to the local client or a 3125 * specific downstream client based on the listen-address/port. 3126 * 6) Agent and X11-Forwarding have a similar problem and are currently 3127 * not supported as the matching session/channel cannot be identified 3128 * easily. 3129 */ 3130 3131 /* 3132 * receive packets from downstream mux clients: 3133 * channel callback fired on read from mux client, creates 3134 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3135 * on channel creation. 3136 */ 3137 int 3138 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3139 { 3140 Channel *c = NULL; 3141 struct sshbuf *original = NULL, *modified = NULL; 3142 const u_char *cp; 3143 char *ctype = NULL, *listen_host = NULL; 3144 u_char type; 3145 size_t have; 3146 int ret = -1, r; 3147 u_int id, remote_id, listen_port; 3148 3149 /* sshbuf_dump(downstream->input, stderr); */ 3150 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3151 != 0) { 3152 error_fr(r, "parse"); 3153 return -1; 3154 } 3155 if (have < 2) { 3156 error_f("short message"); 3157 return -1; 3158 } 3159 type = cp[1]; 3160 /* skip padlen + type */ 3161 cp += 2; 3162 have -= 2; 3163 if (ssh_packet_log_type(type)) 3164 debug3_f("channel %u: down->up: type %u", 3165 downstream->self, type); 3166 3167 switch (type) { 3168 case SSH2_MSG_CHANNEL_OPEN: 3169 if ((original = sshbuf_from(cp, have)) == NULL || 3170 (modified = sshbuf_new()) == NULL) { 3171 error_f("alloc"); 3172 goto out; 3173 } 3174 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3175 (r = sshbuf_get_u32(original, &id)) != 0) { 3176 error_fr(r, "parse"); 3177 goto out; 3178 } 3179 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3180 -1, -1, -1, 0, 0, 0, ctype, 1); 3181 c->mux_ctx = downstream; /* point to mux client */ 3182 c->mux_downstream_id = id; /* original downstream id */ 3183 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3184 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3185 (r = sshbuf_putb(modified, original)) != 0) { 3186 error_fr(r, "compose"); 3187 channel_free(ssh, c); 3188 goto out; 3189 } 3190 break; 3191 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3192 /* 3193 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3194 * need to parse 'remote_id' instead of 'ctype'. 3195 */ 3196 if ((original = sshbuf_from(cp, have)) == NULL || 3197 (modified = sshbuf_new()) == NULL) { 3198 error_f("alloc"); 3199 goto out; 3200 } 3201 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3202 (r = sshbuf_get_u32(original, &id)) != 0) { 3203 error_fr(r, "parse"); 3204 goto out; 3205 } 3206 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3207 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3208 c->mux_ctx = downstream; /* point to mux client */ 3209 c->mux_downstream_id = id; 3210 c->remote_id = remote_id; 3211 c->have_remote_id = 1; 3212 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3213 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3214 (r = sshbuf_putb(modified, original)) != 0) { 3215 error_fr(r, "compose"); 3216 channel_free(ssh, c); 3217 goto out; 3218 } 3219 break; 3220 case SSH2_MSG_GLOBAL_REQUEST: 3221 if ((original = sshbuf_from(cp, have)) == NULL) { 3222 error_f("alloc"); 3223 goto out; 3224 } 3225 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3226 error_fr(r, "parse"); 3227 goto out; 3228 } 3229 if (strcmp(ctype, "tcpip-forward") != 0) { 3230 error_f("unsupported request %s", ctype); 3231 goto out; 3232 } 3233 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3234 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3235 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3236 error_fr(r, "parse"); 3237 goto out; 3238 } 3239 if (listen_port > 65535) { 3240 error_f("tcpip-forward for %s: bad port %u", 3241 listen_host, listen_port); 3242 goto out; 3243 } 3244 /* Record that connection to this host/port is permitted. */ 3245 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", 3246 -1, listen_host, NULL, (int)listen_port, downstream); 3247 break; 3248 case SSH2_MSG_CHANNEL_CLOSE: 3249 if (have < 4) 3250 break; 3251 remote_id = PEEK_U32(cp); 3252 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3253 if (c->flags & CHAN_CLOSE_RCVD) 3254 channel_free(ssh, c); 3255 else 3256 c->flags |= CHAN_CLOSE_SENT; 3257 } 3258 break; 3259 } 3260 if (modified) { 3261 if ((r = sshpkt_start(ssh, type)) != 0 || 3262 (r = sshpkt_putb(ssh, modified)) != 0 || 3263 (r = sshpkt_send(ssh)) != 0) { 3264 error_fr(r, "send"); 3265 goto out; 3266 } 3267 } else { 3268 if ((r = sshpkt_start(ssh, type)) != 0 || 3269 (r = sshpkt_put(ssh, cp, have)) != 0 || 3270 (r = sshpkt_send(ssh)) != 0) { 3271 error_fr(r, "send"); 3272 goto out; 3273 } 3274 } 3275 ret = 0; 3276 out: 3277 free(ctype); 3278 free(listen_host); 3279 sshbuf_free(original); 3280 sshbuf_free(modified); 3281 return ret; 3282 } 3283 3284 /* 3285 * receive packets from upstream server and de-multiplex packets 3286 * to correct downstream: 3287 * implemented as a helper for channel input handlers, 3288 * replaces local (proxy) channel ID with downstream channel ID. 3289 */ 3290 int 3291 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3292 { 3293 struct sshbuf *b = NULL; 3294 Channel *downstream; 3295 const u_char *cp = NULL; 3296 size_t len; 3297 int r; 3298 3299 /* 3300 * When receiving packets from the peer we need to check whether we 3301 * need to forward the packets to the mux client. In this case we 3302 * restore the original channel id and keep track of CLOSE messages, 3303 * so we can cleanup the channel. 3304 */ 3305 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3306 return 0; 3307 if ((downstream = c->mux_ctx) == NULL) 3308 return 0; 3309 switch (type) { 3310 case SSH2_MSG_CHANNEL_CLOSE: 3311 case SSH2_MSG_CHANNEL_DATA: 3312 case SSH2_MSG_CHANNEL_EOF: 3313 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3314 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3315 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3316 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3317 case SSH2_MSG_CHANNEL_SUCCESS: 3318 case SSH2_MSG_CHANNEL_FAILURE: 3319 case SSH2_MSG_CHANNEL_REQUEST: 3320 break; 3321 default: 3322 debug2_f("channel %u: unsupported type %u", c->self, type); 3323 return 0; 3324 } 3325 if ((b = sshbuf_new()) == NULL) { 3326 error_f("alloc reply"); 3327 goto out; 3328 } 3329 /* get remaining payload (after id) */ 3330 cp = sshpkt_ptr(ssh, &len); 3331 if (cp == NULL) { 3332 error_f("no packet"); 3333 goto out; 3334 } 3335 /* translate id and send to muxclient */ 3336 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3337 (r = sshbuf_put_u8(b, type)) != 0 || 3338 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3339 (r = sshbuf_put(b, cp, len)) != 0 || 3340 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3341 error_fr(r, "compose muxclient"); 3342 goto out; 3343 } 3344 /* sshbuf_dump(b, stderr); */ 3345 if (ssh_packet_log_type(type)) 3346 debug3_f("channel %u: up->down: type %u", c->self, type); 3347 out: 3348 /* update state */ 3349 switch (type) { 3350 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3351 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3352 if (cp && len > 4) { 3353 c->remote_id = PEEK_U32(cp); 3354 c->have_remote_id = 1; 3355 } 3356 break; 3357 case SSH2_MSG_CHANNEL_CLOSE: 3358 if (c->flags & CHAN_CLOSE_SENT) 3359 channel_free(ssh, c); 3360 else 3361 c->flags |= CHAN_CLOSE_RCVD; 3362 break; 3363 } 3364 sshbuf_free(b); 3365 return 1; 3366 } 3367 3368 /* -- protocol input */ 3369 3370 /* Parse a channel ID from the current packet */ 3371 static int 3372 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3373 { 3374 u_int32_t id; 3375 int r; 3376 3377 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3378 error_r(r, "%s: parse id", where); 3379 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3380 } 3381 if (id > INT_MAX) { 3382 error_r(r, "%s: bad channel id %u", where, id); 3383 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3384 } 3385 return (int)id; 3386 } 3387 3388 /* Lookup a channel from an ID in the current packet */ 3389 static Channel * 3390 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3391 { 3392 int id = channel_parse_id(ssh, where, what); 3393 Channel *c; 3394 3395 if ((c = channel_lookup(ssh, id)) == NULL) { 3396 ssh_packet_disconnect(ssh, 3397 "%s packet referred to nonexistent channel %d", what, id); 3398 } 3399 return c; 3400 } 3401 3402 int 3403 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3404 { 3405 const u_char *data; 3406 size_t data_len, win_len; 3407 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3408 int r; 3409 3410 if (channel_proxy_upstream(c, type, seq, ssh)) 3411 return 0; 3412 3413 /* Ignore any data for non-open channels (might happen on close) */ 3414 if (c->type != SSH_CHANNEL_OPEN && 3415 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3416 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3417 c->type != SSH_CHANNEL_X11_OPEN) 3418 return 0; 3419 3420 /* Get the data. */ 3421 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3422 (r = sshpkt_get_end(ssh)) != 0) 3423 fatal_fr(r, "channel %i: get data", c->self); 3424 3425 win_len = data_len; 3426 if (c->datagram) 3427 win_len += 4; /* string length header */ 3428 3429 /* 3430 * The sending side reduces its window as it sends data, so we 3431 * must 'fake' consumption of the data in order to ensure that window 3432 * updates are sent back. Otherwise the connection might deadlock. 3433 */ 3434 if (c->ostate != CHAN_OUTPUT_OPEN) { 3435 c->local_window -= win_len; 3436 c->local_consumed += win_len; 3437 return 0; 3438 } 3439 3440 if (win_len > c->local_maxpacket) { 3441 logit("channel %d: rcvd big packet %zu, maxpack %u", 3442 c->self, win_len, c->local_maxpacket); 3443 return 0; 3444 } 3445 if (win_len > c->local_window) { 3446 c->local_window_exceeded += win_len - c->local_window; 3447 logit("channel %d: rcvd too much data %zu, win %u/%u " 3448 "(excess %u)", c->self, win_len, c->local_window, 3449 c->local_window_max, c->local_window_exceeded); 3450 c->local_window = 0; 3451 /* Allow 10% grace before bringing the hammer down */ 3452 if (c->local_window_exceeded > (c->local_window_max / 10)) { 3453 ssh_packet_disconnect(ssh, "channel %d: peer ignored " 3454 "channel window", c->self); 3455 } 3456 } else { 3457 c->local_window -= win_len; 3458 c->local_window_exceeded = 0; 3459 } 3460 3461 if (c->datagram) { 3462 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3463 fatal_fr(r, "channel %i: append datagram", c->self); 3464 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3465 fatal_fr(r, "channel %i: append data", c->self); 3466 3467 return 0; 3468 } 3469 3470 int 3471 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3472 { 3473 const u_char *data; 3474 size_t data_len; 3475 u_int32_t tcode; 3476 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3477 int r; 3478 3479 if (channel_proxy_upstream(c, type, seq, ssh)) 3480 return 0; 3481 if (c->type != SSH_CHANNEL_OPEN) { 3482 logit("channel %d: ext data for non open", c->self); 3483 return 0; 3484 } 3485 if (c->flags & CHAN_EOF_RCVD) { 3486 if (ssh->compat & SSH_BUG_EXTEOF) 3487 debug("channel %d: accepting ext data after eof", 3488 c->self); 3489 else 3490 ssh_packet_disconnect(ssh, "Received extended_data " 3491 "after EOF on channel %d.", c->self); 3492 } 3493 3494 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3495 error_fr(r, "parse tcode"); 3496 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3497 } 3498 if (c->efd == -1 || 3499 c->extended_usage != CHAN_EXTENDED_WRITE || 3500 tcode != SSH2_EXTENDED_DATA_STDERR) { 3501 logit("channel %d: bad ext data", c->self); 3502 return 0; 3503 } 3504 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3505 (r = sshpkt_get_end(ssh)) != 0) { 3506 error_fr(r, "parse data"); 3507 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3508 } 3509 3510 if (data_len > c->local_window) { 3511 logit("channel %d: rcvd too much extended_data %zu, win %u", 3512 c->self, data_len, c->local_window); 3513 return 0; 3514 } 3515 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3516 /* XXX sshpkt_getb? */ 3517 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3518 error_fr(r, "append"); 3519 c->local_window -= data_len; 3520 return 0; 3521 } 3522 3523 int 3524 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3525 { 3526 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3527 int r; 3528 3529 if ((r = sshpkt_get_end(ssh)) != 0) { 3530 error_fr(r, "parse data"); 3531 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3532 } 3533 3534 if (channel_proxy_upstream(c, type, seq, ssh)) 3535 return 0; 3536 chan_rcvd_ieof(ssh, c); 3537 3538 /* XXX force input close */ 3539 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3540 debug("channel %d: FORCE input drain", c->self); 3541 c->istate = CHAN_INPUT_WAIT_DRAIN; 3542 if (sshbuf_len(c->input) == 0) 3543 chan_ibuf_empty(ssh, c); 3544 } 3545 return 0; 3546 } 3547 3548 int 3549 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3550 { 3551 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3552 int r; 3553 3554 if (channel_proxy_upstream(c, type, seq, ssh)) 3555 return 0; 3556 if ((r = sshpkt_get_end(ssh)) != 0) { 3557 error_fr(r, "parse data"); 3558 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3559 } 3560 chan_rcvd_oclose(ssh, c); 3561 return 0; 3562 } 3563 3564 int 3565 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3566 { 3567 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3568 u_int32_t remote_window, remote_maxpacket; 3569 int r; 3570 3571 if (channel_proxy_upstream(c, type, seq, ssh)) 3572 return 0; 3573 if (c->type != SSH_CHANNEL_OPENING) 3574 ssh_packet_disconnect(ssh, "Received open confirmation for " 3575 "non-opening channel %d.", c->self); 3576 /* 3577 * Record the remote channel number and mark that the channel 3578 * is now open. 3579 */ 3580 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3581 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3582 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3583 (r = sshpkt_get_end(ssh)) != 0) { 3584 error_fr(r, "window/maxpacket"); 3585 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3586 } 3587 3588 c->have_remote_id = 1; 3589 c->remote_window = remote_window; 3590 c->remote_maxpacket = remote_maxpacket; 3591 c->type = SSH_CHANNEL_OPEN; 3592 if (c->open_confirm) { 3593 debug2_f("channel %d: callback start", c->self); 3594 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3595 debug2_f("channel %d: callback done", c->self); 3596 } 3597 channel_set_used_time(ssh, c); 3598 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3599 c->remote_window, c->remote_maxpacket); 3600 return 0; 3601 } 3602 3603 static const char * 3604 reason2txt(int reason) 3605 { 3606 switch (reason) { 3607 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3608 return "administratively prohibited"; 3609 case SSH2_OPEN_CONNECT_FAILED: 3610 return "connect failed"; 3611 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3612 return "unknown channel type"; 3613 case SSH2_OPEN_RESOURCE_SHORTAGE: 3614 return "resource shortage"; 3615 } 3616 return "unknown reason"; 3617 } 3618 3619 int 3620 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3621 { 3622 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3623 u_int32_t reason; 3624 char *msg = NULL; 3625 int r; 3626 3627 if (channel_proxy_upstream(c, type, seq, ssh)) 3628 return 0; 3629 if (c->type != SSH_CHANNEL_OPENING) 3630 ssh_packet_disconnect(ssh, "Received open failure for " 3631 "non-opening channel %d.", c->self); 3632 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3633 error_fr(r, "parse reason"); 3634 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3635 } 3636 /* skip language */ 3637 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3638 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3639 (r = sshpkt_get_end(ssh)) != 0) { 3640 error_fr(r, "parse msg/lang"); 3641 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3642 } 3643 logit("channel %d: open failed: %s%s%s", c->self, 3644 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3645 free(msg); 3646 if (c->open_confirm) { 3647 debug2_f("channel %d: callback start", c->self); 3648 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3649 debug2_f("channel %d: callback done", c->self); 3650 } 3651 /* Schedule the channel for cleanup/deletion. */ 3652 chan_mark_dead(ssh, c); 3653 return 0; 3654 } 3655 3656 int 3657 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3658 { 3659 int id = channel_parse_id(ssh, __func__, "window adjust"); 3660 Channel *c; 3661 u_int32_t adjust; 3662 u_int new_rwin; 3663 int r; 3664 3665 if ((c = channel_lookup(ssh, id)) == NULL) { 3666 logit("Received window adjust for non-open channel %d.", id); 3667 return 0; 3668 } 3669 3670 if (channel_proxy_upstream(c, type, seq, ssh)) 3671 return 0; 3672 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3673 (r = sshpkt_get_end(ssh)) != 0) { 3674 error_fr(r, "parse adjust"); 3675 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3676 } 3677 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3678 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3679 fatal("channel %d: adjust %u overflows remote window %u", 3680 c->self, adjust, c->remote_window); 3681 } 3682 c->remote_window = new_rwin; 3683 return 0; 3684 } 3685 3686 int 3687 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3688 { 3689 int id = channel_parse_id(ssh, __func__, "status confirm"); 3690 Channel *c; 3691 struct channel_confirm *cc; 3692 3693 /* Reset keepalive timeout */ 3694 ssh_packet_set_alive_timeouts(ssh, 0); 3695 3696 debug2_f("type %d id %d", type, id); 3697 3698 if ((c = channel_lookup(ssh, id)) == NULL) { 3699 logit_f("%d: unknown", id); 3700 return 0; 3701 } 3702 if (channel_proxy_upstream(c, type, seq, ssh)) 3703 return 0; 3704 if (sshpkt_get_end(ssh) != 0) 3705 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3706 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3707 return 0; 3708 cc->cb(ssh, type, c, cc->ctx); 3709 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3710 freezero(cc, sizeof(*cc)); 3711 return 0; 3712 } 3713 3714 /* -- tcp forwarding */ 3715 3716 void 3717 channel_set_af(struct ssh *ssh, int af) 3718 { 3719 ssh->chanctxt->IPv4or6 = af; 3720 } 3721 3722 void 3723 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size) 3724 { 3725 hpn_disabled = external_hpn_disabled; 3726 hpn_buffer_size = external_hpn_buffer_size; 3727 debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size); 3728 } 3729 3730 /* 3731 * Determine whether or not a port forward listens to loopback, the 3732 * specified address or wildcard. On the client, a specified bind 3733 * address will always override gateway_ports. On the server, a 3734 * gateway_ports of 1 (``yes'') will override the client's specification 3735 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3736 * will bind to whatever address the client asked for. 3737 * 3738 * Special-case listen_addrs are: 3739 * 3740 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3741 * "" (empty string), "*" -> wildcard v4/v6 3742 * "localhost" -> loopback v4/v6 3743 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3744 */ 3745 static const char * 3746 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3747 int is_client, struct ForwardOptions *fwd_opts) 3748 { 3749 const char *addr = NULL; 3750 int wildcard = 0; 3751 3752 if (listen_addr == NULL) { 3753 /* No address specified: default to gateway_ports setting */ 3754 if (fwd_opts->gateway_ports) 3755 wildcard = 1; 3756 } else if (fwd_opts->gateway_ports || is_client) { 3757 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3758 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3759 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3760 (!is_client && fwd_opts->gateway_ports == 1)) { 3761 wildcard = 1; 3762 /* 3763 * Notify client if they requested a specific listen 3764 * address and it was overridden. 3765 */ 3766 if (*listen_addr != '\0' && 3767 strcmp(listen_addr, "0.0.0.0") != 0 && 3768 strcmp(listen_addr, "*") != 0) { 3769 ssh_packet_send_debug(ssh, 3770 "Forwarding listen address " 3771 "\"%s\" overridden by server " 3772 "GatewayPorts", listen_addr); 3773 } 3774 } else if (strcmp(listen_addr, "localhost") != 0 || 3775 strcmp(listen_addr, "127.0.0.1") == 0 || 3776 strcmp(listen_addr, "::1") == 0) { 3777 /* 3778 * Accept explicit localhost address when 3779 * GatewayPorts=yes. The "localhost" hostname is 3780 * deliberately skipped here so it will listen on all 3781 * available local address families. 3782 */ 3783 addr = listen_addr; 3784 } 3785 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3786 strcmp(listen_addr, "::1") == 0) { 3787 /* 3788 * If a specific IPv4/IPv6 localhost address has been 3789 * requested then accept it even if gateway_ports is in 3790 * effect. This allows the client to prefer IPv4 or IPv6. 3791 */ 3792 addr = listen_addr; 3793 } 3794 if (wildcardp != NULL) 3795 *wildcardp = wildcard; 3796 return addr; 3797 } 3798 3799 static int 3800 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3801 struct Forward *fwd, int *allocated_listen_port, 3802 struct ForwardOptions *fwd_opts) 3803 { 3804 Channel *c; 3805 int sock, r, success = 0, wildcard = 0, is_client; 3806 struct addrinfo hints, *ai, *aitop; 3807 const char *host, *addr; 3808 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3809 in_port_t *lport_p; 3810 3811 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3812 3813 if (is_client && fwd->connect_path != NULL) { 3814 host = fwd->connect_path; 3815 } else { 3816 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3817 fwd->listen_host : fwd->connect_host; 3818 if (host == NULL) { 3819 error("No forward host name."); 3820 return 0; 3821 } 3822 if (strlen(host) >= NI_MAXHOST) { 3823 error("Forward host name too long."); 3824 return 0; 3825 } 3826 } 3827 3828 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3829 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3830 is_client, fwd_opts); 3831 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3832 (addr == NULL) ? "NULL" : addr); 3833 3834 /* 3835 * getaddrinfo returns a loopback address if the hostname is 3836 * set to NULL and hints.ai_flags is not AI_PASSIVE 3837 */ 3838 memset(&hints, 0, sizeof(hints)); 3839 hints.ai_family = ssh->chanctxt->IPv4or6; 3840 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3841 hints.ai_socktype = SOCK_STREAM; 3842 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3843 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3844 if (addr == NULL) { 3845 /* This really shouldn't happen */ 3846 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3847 ssh_gai_strerror(r)); 3848 } else { 3849 error_f("getaddrinfo(%.64s): %s", addr, 3850 ssh_gai_strerror(r)); 3851 } 3852 return 0; 3853 } 3854 if (allocated_listen_port != NULL) 3855 *allocated_listen_port = 0; 3856 for (ai = aitop; ai; ai = ai->ai_next) { 3857 switch (ai->ai_family) { 3858 case AF_INET: 3859 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3860 sin_port; 3861 break; 3862 case AF_INET6: 3863 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3864 sin6_port; 3865 break; 3866 default: 3867 continue; 3868 } 3869 /* 3870 * If allocating a port for -R forwards, then use the 3871 * same port for all address families. 3872 */ 3873 if (type == SSH_CHANNEL_RPORT_LISTENER && 3874 fwd->listen_port == 0 && allocated_listen_port != NULL && 3875 *allocated_listen_port > 0) 3876 *lport_p = htons(*allocated_listen_port); 3877 3878 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3879 strport, sizeof(strport), 3880 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3881 error_f("getnameinfo failed"); 3882 continue; 3883 } 3884 /* Create a port to listen for the host. */ 3885 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3886 if (sock == -1) { 3887 /* this is no error since kernel may not support ipv6 */ 3888 verbose("socket [%s]:%s: %.100s", ntop, strport, 3889 strerror(errno)); 3890 continue; 3891 } 3892 3893 set_reuseaddr(sock); 3894 3895 debug("Local forwarding listening on %s port %s.", 3896 ntop, strport); 3897 3898 /* Bind the socket to the address. */ 3899 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3900 /* 3901 * address can be in if use ipv6 address is 3902 * already bound 3903 */ 3904 verbose("bind [%s]:%s: %.100s", 3905 ntop, strport, strerror(errno)); 3906 close(sock); 3907 continue; 3908 } 3909 /* Start listening for connections on the socket. */ 3910 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3911 error("listen [%s]:%s: %.100s", ntop, strport, 3912 strerror(errno)); 3913 close(sock); 3914 continue; 3915 } 3916 3917 /* 3918 * fwd->listen_port == 0 requests a dynamically allocated port - 3919 * record what we got. 3920 */ 3921 if (type == SSH_CHANNEL_RPORT_LISTENER && 3922 fwd->listen_port == 0 && 3923 allocated_listen_port != NULL && 3924 *allocated_listen_port == 0) { 3925 *allocated_listen_port = get_local_port(sock); 3926 debug("Allocated listen port %d", 3927 *allocated_listen_port); 3928 } 3929 3930 /* Allocate a channel number for the socket. */ 3931 /* explicitly test for hpn disabled option. if true use smaller window size */ 3932 if (hpn_disabled) 3933 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3934 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3935 0, "port listener", 1); 3936 else 3937 c = channel_new(ssh, "port listener", type, sock, sock, 3938 -1, hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 3939 0, "port listener", 1); 3940 c->path = xstrdup(host); 3941 c->host_port = fwd->connect_port; 3942 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3943 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3944 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3945 c->listening_port = *allocated_listen_port; 3946 else 3947 c->listening_port = fwd->listen_port; 3948 success = 1; 3949 } 3950 if (success == 0) 3951 error_f("cannot listen to port: %d", fwd->listen_port); 3952 freeaddrinfo(aitop); 3953 return success; 3954 } 3955 3956 static int 3957 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3958 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3959 { 3960 struct sockaddr_un sunaddr; 3961 const char *path; 3962 Channel *c; 3963 int port, sock; 3964 mode_t omask; 3965 3966 switch (type) { 3967 case SSH_CHANNEL_UNIX_LISTENER: 3968 if (fwd->connect_path != NULL) { 3969 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3970 error("Local connecting path too long: %s", 3971 fwd->connect_path); 3972 return 0; 3973 } 3974 path = fwd->connect_path; 3975 port = PORT_STREAMLOCAL; 3976 } else { 3977 if (fwd->connect_host == NULL) { 3978 error("No forward host name."); 3979 return 0; 3980 } 3981 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3982 error("Forward host name too long."); 3983 return 0; 3984 } 3985 path = fwd->connect_host; 3986 port = fwd->connect_port; 3987 } 3988 break; 3989 case SSH_CHANNEL_RUNIX_LISTENER: 3990 path = fwd->listen_path; 3991 port = PORT_STREAMLOCAL; 3992 break; 3993 default: 3994 error_f("unexpected channel type %d", type); 3995 return 0; 3996 } 3997 3998 if (fwd->listen_path == NULL) { 3999 error("No forward path name."); 4000 return 0; 4001 } 4002 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 4003 error("Local listening path too long: %s", fwd->listen_path); 4004 return 0; 4005 } 4006 4007 debug3_f("type %d path %s", type, fwd->listen_path); 4008 4009 /* Start a Unix domain listener. */ 4010 omask = umask(fwd_opts->streamlocal_bind_mask); 4011 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 4012 fwd_opts->streamlocal_bind_unlink); 4013 umask(omask); 4014 if (sock < 0) 4015 return 0; 4016 4017 debug("Local forwarding listening on path %s.", fwd->listen_path); 4018 4019 /* Allocate a channel number for the socket. */ 4020 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 4021 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 4022 0, "unix listener", 1); 4023 c->path = xstrdup(path); 4024 c->host_port = port; 4025 c->listening_port = PORT_STREAMLOCAL; 4026 c->listening_addr = xstrdup(fwd->listen_path); 4027 return 1; 4028 } 4029 4030 static int 4031 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 4032 const char *host, u_short port) 4033 { 4034 u_int i; 4035 int found = 0; 4036 4037 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4038 Channel *c = ssh->chanctxt->channels[i]; 4039 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 4040 continue; 4041 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 4042 debug2_f("close channel %d", i); 4043 channel_free(ssh, c); 4044 found = 1; 4045 } 4046 } 4047 4048 return found; 4049 } 4050 4051 static int 4052 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 4053 { 4054 u_int i; 4055 int found = 0; 4056 4057 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4058 Channel *c = ssh->chanctxt->channels[i]; 4059 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 4060 continue; 4061 if (c->path == NULL) 4062 continue; 4063 if (strcmp(c->path, path) == 0) { 4064 debug2_f("close channel %d", i); 4065 channel_free(ssh, c); 4066 found = 1; 4067 } 4068 } 4069 4070 return found; 4071 } 4072 4073 int 4074 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4075 { 4076 if (fwd->listen_path != NULL) { 4077 return channel_cancel_rport_listener_streamlocal(ssh, 4078 fwd->listen_path); 4079 } else { 4080 return channel_cancel_rport_listener_tcpip(ssh, 4081 fwd->listen_host, fwd->listen_port); 4082 } 4083 } 4084 4085 static int 4086 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4087 const char *lhost, u_short lport, int cport, 4088 struct ForwardOptions *fwd_opts) 4089 { 4090 u_int i; 4091 int found = 0; 4092 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4093 4094 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4095 Channel *c = ssh->chanctxt->channels[i]; 4096 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4097 continue; 4098 if (c->listening_port != lport) 4099 continue; 4100 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4101 /* skip dynamic forwardings */ 4102 if (c->host_port == 0) 4103 continue; 4104 } else { 4105 if (c->host_port != cport) 4106 continue; 4107 } 4108 if ((c->listening_addr == NULL && addr != NULL) || 4109 (c->listening_addr != NULL && addr == NULL)) 4110 continue; 4111 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4112 debug2_f("close channel %d", i); 4113 channel_free(ssh, c); 4114 found = 1; 4115 } 4116 } 4117 4118 return found; 4119 } 4120 4121 static int 4122 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4123 { 4124 u_int i; 4125 int found = 0; 4126 4127 if (path == NULL) { 4128 error_f("no path specified."); 4129 return 0; 4130 } 4131 4132 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4133 Channel *c = ssh->chanctxt->channels[i]; 4134 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4135 continue; 4136 if (c->listening_addr == NULL) 4137 continue; 4138 if (strcmp(c->listening_addr, path) == 0) { 4139 debug2_f("close channel %d", i); 4140 channel_free(ssh, c); 4141 found = 1; 4142 } 4143 } 4144 4145 return found; 4146 } 4147 4148 int 4149 channel_cancel_lport_listener(struct ssh *ssh, 4150 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4151 { 4152 if (fwd->listen_path != NULL) { 4153 return channel_cancel_lport_listener_streamlocal(ssh, 4154 fwd->listen_path); 4155 } else { 4156 return channel_cancel_lport_listener_tcpip(ssh, 4157 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4158 } 4159 } 4160 4161 /* protocol local port fwd, used by ssh */ 4162 int 4163 channel_setup_local_fwd_listener(struct ssh *ssh, 4164 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4165 { 4166 if (fwd->listen_path != NULL) { 4167 return channel_setup_fwd_listener_streamlocal(ssh, 4168 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4169 } else { 4170 return channel_setup_fwd_listener_tcpip(ssh, 4171 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4172 } 4173 } 4174 4175 /* Matches a remote forwarding permission against a requested forwarding */ 4176 static int 4177 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4178 { 4179 int ret; 4180 char *lhost; 4181 4182 /* XXX add ACLs for streamlocal */ 4183 if (fwd->listen_path != NULL) 4184 return 1; 4185 4186 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4187 return 0; 4188 4189 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4190 allowed_open->listen_port != fwd->listen_port) 4191 return 0; 4192 4193 /* Match hostnames case-insensitively */ 4194 lhost = xstrdup(fwd->listen_host); 4195 lowercase(lhost); 4196 ret = match_pattern(lhost, allowed_open->listen_host); 4197 free(lhost); 4198 4199 return ret; 4200 } 4201 4202 /* Checks whether a requested remote forwarding is permitted */ 4203 static int 4204 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4205 { 4206 struct ssh_channels *sc = ssh->chanctxt; 4207 struct permission_set *pset = &sc->remote_perms; 4208 u_int i, permit, permit_adm = 1; 4209 struct permission *perm; 4210 4211 /* XXX apply GatewayPorts override before checking? */ 4212 4213 permit = pset->all_permitted; 4214 if (!permit) { 4215 for (i = 0; i < pset->num_permitted_user; i++) { 4216 perm = &pset->permitted_user[i]; 4217 if (remote_open_match(perm, fwd)) { 4218 permit = 1; 4219 break; 4220 } 4221 } 4222 } 4223 4224 if (pset->num_permitted_admin > 0) { 4225 permit_adm = 0; 4226 for (i = 0; i < pset->num_permitted_admin; i++) { 4227 perm = &pset->permitted_admin[i]; 4228 if (remote_open_match(perm, fwd)) { 4229 permit_adm = 1; 4230 break; 4231 } 4232 } 4233 } 4234 4235 return permit && permit_adm; 4236 } 4237 4238 /* protocol v2 remote port fwd, used by sshd */ 4239 int 4240 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4241 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4242 { 4243 if (!check_rfwd_permission(ssh, fwd)) { 4244 ssh_packet_send_debug(ssh, "port forwarding refused"); 4245 if (fwd->listen_path != NULL) 4246 /* XXX always allowed, see remote_open_match() */ 4247 logit("Received request from %.100s port %d to " 4248 "remote forward to path \"%.100s\", " 4249 "but the request was denied.", 4250 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4251 fwd->listen_path); 4252 else if(fwd->listen_host != NULL) 4253 logit("Received request from %.100s port %d to " 4254 "remote forward to host %.100s port %d, " 4255 "but the request was denied.", 4256 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4257 fwd->listen_host, fwd->listen_port ); 4258 else 4259 logit("Received request from %.100s port %d to remote " 4260 "forward, but the request was denied.", 4261 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4262 return 0; 4263 } 4264 if (fwd->listen_path != NULL) { 4265 return channel_setup_fwd_listener_streamlocal(ssh, 4266 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4267 } else { 4268 return channel_setup_fwd_listener_tcpip(ssh, 4269 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4270 fwd_opts); 4271 } 4272 } 4273 4274 /* 4275 * Translate the requested rfwd listen host to something usable for 4276 * this server. 4277 */ 4278 static const char * 4279 channel_rfwd_bind_host(const char *listen_host) 4280 { 4281 if (listen_host == NULL) { 4282 return "localhost"; 4283 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4284 return ""; 4285 } else 4286 return listen_host; 4287 } 4288 4289 /* 4290 * Initiate forwarding of connections to port "port" on remote host through 4291 * the secure channel to host:port from local side. 4292 * Returns handle (index) for updating the dynamic listen port with 4293 * channel_update_permission(). 4294 */ 4295 int 4296 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4297 { 4298 int r, success = 0, idx = -1; 4299 const char *host_to_connect, *listen_host, *listen_path; 4300 int port_to_connect, listen_port; 4301 4302 /* Send the forward request to the remote side. */ 4303 if (fwd->listen_path != NULL) { 4304 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4305 (r = sshpkt_put_cstring(ssh, 4306 "streamlocal-forward@openssh.com")) != 0 || 4307 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4308 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4309 (r = sshpkt_send(ssh)) != 0 || 4310 (r = ssh_packet_write_wait(ssh)) < 0) 4311 fatal_fr(r, "request streamlocal"); 4312 } else { 4313 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4314 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4315 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4316 (r = sshpkt_put_cstring(ssh, 4317 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4318 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4319 (r = sshpkt_send(ssh)) != 0 || 4320 (r = ssh_packet_write_wait(ssh)) < 0) 4321 fatal_fr(r, "request tcpip-forward"); 4322 } 4323 /* Assume that server accepts the request */ 4324 success = 1; 4325 if (success) { 4326 /* Record that connection to this host/port is permitted. */ 4327 host_to_connect = listen_host = listen_path = NULL; 4328 port_to_connect = listen_port = 0; 4329 if (fwd->connect_path != NULL) { 4330 host_to_connect = fwd->connect_path; 4331 port_to_connect = PORT_STREAMLOCAL; 4332 } else { 4333 host_to_connect = fwd->connect_host; 4334 port_to_connect = fwd->connect_port; 4335 } 4336 if (fwd->listen_path != NULL) { 4337 listen_path = fwd->listen_path; 4338 listen_port = PORT_STREAMLOCAL; 4339 } else { 4340 listen_host = fwd->listen_host; 4341 listen_port = fwd->listen_port; 4342 } 4343 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4344 host_to_connect, port_to_connect, 4345 listen_host, listen_path, listen_port, NULL); 4346 } 4347 return idx; 4348 } 4349 4350 static int 4351 open_match(struct permission *allowed_open, const char *requestedhost, 4352 int requestedport) 4353 { 4354 if (allowed_open->host_to_connect == NULL) 4355 return 0; 4356 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4357 allowed_open->port_to_connect != requestedport) 4358 return 0; 4359 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4360 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4361 return 0; 4362 return 1; 4363 } 4364 4365 /* 4366 * Note that in the listen host/port case 4367 * we don't support FWD_PERMIT_ANY_PORT and 4368 * need to translate between the configured-host (listen_host) 4369 * and what we've sent to the remote server (channel_rfwd_bind_host) 4370 */ 4371 static int 4372 open_listen_match_tcpip(struct permission *allowed_open, 4373 const char *requestedhost, u_short requestedport, int translate) 4374 { 4375 const char *allowed_host; 4376 4377 if (allowed_open->host_to_connect == NULL) 4378 return 0; 4379 if (allowed_open->listen_port != requestedport) 4380 return 0; 4381 if (!translate && allowed_open->listen_host == NULL && 4382 requestedhost == NULL) 4383 return 1; 4384 allowed_host = translate ? 4385 channel_rfwd_bind_host(allowed_open->listen_host) : 4386 allowed_open->listen_host; 4387 if (allowed_host == NULL || requestedhost == NULL || 4388 strcmp(allowed_host, requestedhost) != 0) 4389 return 0; 4390 return 1; 4391 } 4392 4393 static int 4394 open_listen_match_streamlocal(struct permission *allowed_open, 4395 const char *requestedpath) 4396 { 4397 if (allowed_open->host_to_connect == NULL) 4398 return 0; 4399 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4400 return 0; 4401 if (allowed_open->listen_path == NULL || 4402 strcmp(allowed_open->listen_path, requestedpath) != 0) 4403 return 0; 4404 return 1; 4405 } 4406 4407 /* 4408 * Request cancellation of remote forwarding of connection host:port from 4409 * local side. 4410 */ 4411 static int 4412 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4413 const char *host, u_short port) 4414 { 4415 struct ssh_channels *sc = ssh->chanctxt; 4416 struct permission_set *pset = &sc->local_perms; 4417 int r; 4418 u_int i; 4419 struct permission *perm = NULL; 4420 4421 for (i = 0; i < pset->num_permitted_user; i++) { 4422 perm = &pset->permitted_user[i]; 4423 if (open_listen_match_tcpip(perm, host, port, 0)) 4424 break; 4425 perm = NULL; 4426 } 4427 if (perm == NULL) { 4428 debug_f("requested forward not found"); 4429 return -1; 4430 } 4431 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4432 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4433 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4434 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4435 (r = sshpkt_put_u32(ssh, port)) != 0 || 4436 (r = sshpkt_send(ssh)) != 0) 4437 fatal_fr(r, "send cancel"); 4438 4439 fwd_perm_clear(perm); /* unregister */ 4440 4441 return 0; 4442 } 4443 4444 /* 4445 * Request cancellation of remote forwarding of Unix domain socket 4446 * path from local side. 4447 */ 4448 static int 4449 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4450 { 4451 struct ssh_channels *sc = ssh->chanctxt; 4452 struct permission_set *pset = &sc->local_perms; 4453 int r; 4454 u_int i; 4455 struct permission *perm = NULL; 4456 4457 for (i = 0; i < pset->num_permitted_user; i++) { 4458 perm = &pset->permitted_user[i]; 4459 if (open_listen_match_streamlocal(perm, path)) 4460 break; 4461 perm = NULL; 4462 } 4463 if (perm == NULL) { 4464 debug_f("requested forward not found"); 4465 return -1; 4466 } 4467 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4468 (r = sshpkt_put_cstring(ssh, 4469 "cancel-streamlocal-forward@openssh.com")) != 0 || 4470 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4471 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4472 (r = sshpkt_send(ssh)) != 0) 4473 fatal_fr(r, "send cancel"); 4474 4475 fwd_perm_clear(perm); /* unregister */ 4476 4477 return 0; 4478 } 4479 4480 /* 4481 * Request cancellation of remote forwarding of a connection from local side. 4482 */ 4483 int 4484 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4485 { 4486 if (fwd->listen_path != NULL) { 4487 return channel_request_rforward_cancel_streamlocal(ssh, 4488 fwd->listen_path); 4489 } else { 4490 return channel_request_rforward_cancel_tcpip(ssh, 4491 fwd->listen_host, 4492 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4493 } 4494 } 4495 4496 /* 4497 * Permits opening to any host/port if permitted_user[] is empty. This is 4498 * usually called by the server, because the user could connect to any port 4499 * anyway, and the server has no way to know but to trust the client anyway. 4500 */ 4501 void 4502 channel_permit_all(struct ssh *ssh, int where) 4503 { 4504 struct permission_set *pset = permission_set_get(ssh, where); 4505 4506 if (pset->num_permitted_user == 0) 4507 pset->all_permitted = 1; 4508 } 4509 4510 /* 4511 * Permit the specified host/port for forwarding. 4512 */ 4513 void 4514 channel_add_permission(struct ssh *ssh, int who, int where, 4515 char *host, int port) 4516 { 4517 int local = where == FORWARD_LOCAL; 4518 struct permission_set *pset = permission_set_get(ssh, where); 4519 4520 debug("allow %s forwarding to host %s port %d", 4521 fwd_ident(who, where), host, port); 4522 /* 4523 * Remote forwards set listen_host/port, local forwards set 4524 * host/port_to_connect. 4525 */ 4526 permission_set_add(ssh, who, where, 4527 local ? host : 0, local ? port : 0, 4528 local ? NULL : host, NULL, local ? 0 : port, NULL); 4529 pset->all_permitted = 0; 4530 } 4531 4532 /* 4533 * Administratively disable forwarding. 4534 */ 4535 void 4536 channel_disable_admin(struct ssh *ssh, int where) 4537 { 4538 channel_clear_permission(ssh, FORWARD_ADM, where); 4539 permission_set_add(ssh, FORWARD_ADM, where, 4540 NULL, 0, NULL, NULL, 0, NULL); 4541 } 4542 4543 /* 4544 * Clear a list of permitted opens. 4545 */ 4546 void 4547 channel_clear_permission(struct ssh *ssh, int who, int where) 4548 { 4549 struct permission **permp; 4550 u_int *npermp; 4551 4552 permission_set_get_array(ssh, who, where, &permp, &npermp); 4553 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4554 *npermp = 0; 4555 } 4556 4557 /* 4558 * Update the listen port for a dynamic remote forward, after 4559 * the actual 'newport' has been allocated. If 'newport' < 0 is 4560 * passed then they entry will be invalidated. 4561 */ 4562 void 4563 channel_update_permission(struct ssh *ssh, int idx, int newport) 4564 { 4565 struct permission_set *pset = &ssh->chanctxt->local_perms; 4566 4567 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4568 debug_f("index out of range: %d num_permitted_user %d", 4569 idx, pset->num_permitted_user); 4570 return; 4571 } 4572 debug("%s allowed port %d for forwarding to host %s port %d", 4573 newport > 0 ? "Updating" : "Removing", 4574 newport, 4575 pset->permitted_user[idx].host_to_connect, 4576 pset->permitted_user[idx].port_to_connect); 4577 if (newport <= 0) 4578 fwd_perm_clear(&pset->permitted_user[idx]); 4579 else { 4580 pset->permitted_user[idx].listen_port = 4581 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4582 } 4583 } 4584 4585 /* Try to start non-blocking connect to next host in cctx list */ 4586 static int 4587 connect_next(struct channel_connect *cctx) 4588 { 4589 int sock, saved_errno; 4590 struct sockaddr_un *sunaddr; 4591 char ntop[NI_MAXHOST]; 4592 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4593 4594 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4595 switch (cctx->ai->ai_family) { 4596 case AF_UNIX: 4597 /* unix:pathname instead of host:port */ 4598 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4599 strlcpy(ntop, "unix", sizeof(ntop)); 4600 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4601 break; 4602 case AF_INET: 4603 case AF_INET6: 4604 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4605 ntop, sizeof(ntop), strport, sizeof(strport), 4606 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4607 error_f("getnameinfo failed"); 4608 continue; 4609 } 4610 break; 4611 default: 4612 continue; 4613 } 4614 debug_f("start for host %.100s ([%.100s]:%s)", 4615 cctx->host, ntop, strport); 4616 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4617 cctx->ai->ai_protocol)) == -1) { 4618 if (cctx->ai->ai_next == NULL) 4619 error("socket: %.100s", strerror(errno)); 4620 else 4621 verbose("socket: %.100s", strerror(errno)); 4622 continue; 4623 } 4624 if (set_nonblock(sock) == -1) 4625 fatal_f("set_nonblock(%d)", sock); 4626 if (connect(sock, cctx->ai->ai_addr, 4627 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4628 debug_f("host %.100s ([%.100s]:%s): %.100s", 4629 cctx->host, ntop, strport, strerror(errno)); 4630 saved_errno = errno; 4631 close(sock); 4632 errno = saved_errno; 4633 continue; /* fail -- try next */ 4634 } 4635 if (cctx->ai->ai_family != AF_UNIX) 4636 set_nodelay(sock); 4637 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4638 cctx->host, ntop, strport, sock); 4639 cctx->ai = cctx->ai->ai_next; 4640 return sock; 4641 } 4642 return -1; 4643 } 4644 4645 static void 4646 channel_connect_ctx_free(struct channel_connect *cctx) 4647 { 4648 free(cctx->host); 4649 if (cctx->aitop) { 4650 if (cctx->aitop->ai_family == AF_UNIX) 4651 free(cctx->aitop); 4652 else 4653 freeaddrinfo(cctx->aitop); 4654 } 4655 memset(cctx, 0, sizeof(*cctx)); 4656 } 4657 4658 /* 4659 * Return connecting socket to remote host:port or local socket path, 4660 * passing back the failure reason if appropriate. 4661 */ 4662 static int 4663 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4664 const char *ctype, const char *rname, struct channel_connect *cctx, 4665 int *reason, const char **errmsg) 4666 { 4667 struct addrinfo hints; 4668 int gaierr; 4669 int sock = -1; 4670 char strport[NI_MAXSERV]; 4671 4672 if (port == PORT_STREAMLOCAL) { 4673 struct sockaddr_un *sunaddr; 4674 struct addrinfo *ai; 4675 4676 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4677 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4678 return -1; 4679 } 4680 4681 /* 4682 * Fake up a struct addrinfo for AF_UNIX connections. 4683 * channel_connect_ctx_free() must check ai_family 4684 * and use free() not freeaddirinfo() for AF_UNIX. 4685 */ 4686 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4687 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4688 ai->ai_addr = (struct sockaddr *)(ai + 1); 4689 ai->ai_addrlen = sizeof(*sunaddr); 4690 ai->ai_family = AF_UNIX; 4691 ai->ai_socktype = socktype; 4692 ai->ai_protocol = PF_UNSPEC; 4693 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4694 sunaddr->sun_family = AF_UNIX; 4695 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4696 cctx->aitop = ai; 4697 } else { 4698 memset(&hints, 0, sizeof(hints)); 4699 hints.ai_family = ssh->chanctxt->IPv4or6; 4700 hints.ai_socktype = socktype; 4701 snprintf(strport, sizeof strport, "%d", port); 4702 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4703 != 0) { 4704 if (errmsg != NULL) 4705 *errmsg = ssh_gai_strerror(gaierr); 4706 if (reason != NULL) 4707 *reason = SSH2_OPEN_CONNECT_FAILED; 4708 error("connect_to %.100s: unknown host (%s)", name, 4709 ssh_gai_strerror(gaierr)); 4710 return -1; 4711 } 4712 } 4713 4714 cctx->host = xstrdup(name); 4715 cctx->port = port; 4716 cctx->ai = cctx->aitop; 4717 4718 if ((sock = connect_next(cctx)) == -1) { 4719 error("connect to %.100s port %d failed: %s", 4720 name, port, strerror(errno)); 4721 return -1; 4722 } 4723 4724 return sock; 4725 } 4726 4727 /* Return CONNECTING channel to remote host:port or local socket path */ 4728 static Channel * 4729 connect_to(struct ssh *ssh, const char *host, int port, 4730 const char *ctype, const char *rname) 4731 { 4732 struct channel_connect cctx; 4733 Channel *c; 4734 int sock; 4735 4736 memset(&cctx, 0, sizeof(cctx)); 4737 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4738 &cctx, NULL, NULL); 4739 if (sock == -1) { 4740 channel_connect_ctx_free(&cctx); 4741 return NULL; 4742 } 4743 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4744 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4745 c->host_port = port; 4746 c->path = xstrdup(host); 4747 c->connect_ctx = cctx; 4748 4749 return c; 4750 } 4751 4752 /* 4753 * returns either the newly connected channel or the downstream channel 4754 * that needs to deal with this connection. 4755 */ 4756 Channel * 4757 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4758 u_short listen_port, const char *ctype, const char *rname) 4759 { 4760 struct ssh_channels *sc = ssh->chanctxt; 4761 struct permission_set *pset = &sc->local_perms; 4762 u_int i; 4763 struct permission *perm; 4764 4765 for (i = 0; i < pset->num_permitted_user; i++) { 4766 perm = &pset->permitted_user[i]; 4767 if (open_listen_match_tcpip(perm, 4768 listen_host, listen_port, 1)) { 4769 if (perm->downstream) 4770 return perm->downstream; 4771 if (perm->port_to_connect == 0) 4772 return rdynamic_connect_prepare(ssh, 4773 ctype, rname); 4774 return connect_to(ssh, 4775 perm->host_to_connect, perm->port_to_connect, 4776 ctype, rname); 4777 } 4778 } 4779 error("WARNING: Server requests forwarding for unknown listen_port %d", 4780 listen_port); 4781 return NULL; 4782 } 4783 4784 Channel * 4785 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4786 const char *ctype, const char *rname) 4787 { 4788 struct ssh_channels *sc = ssh->chanctxt; 4789 struct permission_set *pset = &sc->local_perms; 4790 u_int i; 4791 struct permission *perm; 4792 4793 for (i = 0; i < pset->num_permitted_user; i++) { 4794 perm = &pset->permitted_user[i]; 4795 if (open_listen_match_streamlocal(perm, path)) { 4796 return connect_to(ssh, 4797 perm->host_to_connect, perm->port_to_connect, 4798 ctype, rname); 4799 } 4800 } 4801 error("WARNING: Server requests forwarding for unknown path %.100s", 4802 path); 4803 return NULL; 4804 } 4805 4806 /* Check if connecting to that port is permitted and connect. */ 4807 Channel * 4808 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4809 const char *ctype, const char *rname, int *reason, const char **errmsg) 4810 { 4811 struct ssh_channels *sc = ssh->chanctxt; 4812 struct permission_set *pset = &sc->local_perms; 4813 struct channel_connect cctx; 4814 Channel *c; 4815 u_int i, permit, permit_adm = 1; 4816 int sock; 4817 struct permission *perm; 4818 4819 permit = pset->all_permitted; 4820 if (!permit) { 4821 for (i = 0; i < pset->num_permitted_user; i++) { 4822 perm = &pset->permitted_user[i]; 4823 if (open_match(perm, host, port)) { 4824 permit = 1; 4825 break; 4826 } 4827 } 4828 } 4829 4830 if (pset->num_permitted_admin > 0) { 4831 permit_adm = 0; 4832 for (i = 0; i < pset->num_permitted_admin; i++) { 4833 perm = &pset->permitted_admin[i]; 4834 if (open_match(perm, host, port)) { 4835 permit_adm = 1; 4836 break; 4837 } 4838 } 4839 } 4840 4841 if (!permit || !permit_adm) { 4842 logit("Received request from %.100s port %d to connect to " 4843 "host %.100s port %d, but the request was denied.", 4844 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4845 if (reason != NULL) 4846 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4847 return NULL; 4848 } 4849 4850 memset(&cctx, 0, sizeof(cctx)); 4851 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4852 &cctx, reason, errmsg); 4853 if (sock == -1) { 4854 channel_connect_ctx_free(&cctx); 4855 return NULL; 4856 } 4857 4858 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4859 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4860 c->host_port = port; 4861 c->path = xstrdup(host); 4862 c->connect_ctx = cctx; 4863 4864 return c; 4865 } 4866 4867 /* Check if connecting to that path is permitted and connect. */ 4868 Channel * 4869 channel_connect_to_path(struct ssh *ssh, const char *path, const char *ctype, 4870 const char *rname) 4871 { 4872 struct ssh_channels *sc = ssh->chanctxt; 4873 struct permission_set *pset = &sc->local_perms; 4874 u_int i, permit, permit_adm = 1; 4875 struct permission *perm; 4876 4877 permit = pset->all_permitted; 4878 if (!permit) { 4879 for (i = 0; i < pset->num_permitted_user; i++) { 4880 perm = &pset->permitted_user[i]; 4881 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4882 permit = 1; 4883 break; 4884 } 4885 } 4886 } 4887 4888 if (pset->num_permitted_admin > 0) { 4889 permit_adm = 0; 4890 for (i = 0; i < pset->num_permitted_admin; i++) { 4891 perm = &pset->permitted_admin[i]; 4892 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4893 permit_adm = 1; 4894 break; 4895 } 4896 } 4897 } 4898 4899 if (!permit || !permit_adm) { 4900 logit("Received request to connect to path %.100s, " 4901 "but the request was denied.", path); 4902 return NULL; 4903 } 4904 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4905 } 4906 4907 void 4908 channel_send_window_changes(struct ssh *ssh) 4909 { 4910 struct ssh_channels *sc = ssh->chanctxt; 4911 struct winsize ws; 4912 int r; 4913 u_int i; 4914 4915 for (i = 0; i < sc->channels_alloc; i++) { 4916 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4917 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4918 continue; 4919 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4920 continue; 4921 channel_request_start(ssh, i, "window-change", 0); 4922 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4923 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4924 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4925 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4926 (r = sshpkt_send(ssh)) != 0) 4927 fatal_fr(r, "channel %u; send window-change", i); 4928 } 4929 } 4930 4931 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4932 static Channel * 4933 rdynamic_connect_prepare(struct ssh *ssh, const char *ctype, const char *rname) 4934 { 4935 Channel *c; 4936 int r; 4937 4938 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4939 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4940 c->host_port = 0; 4941 c->path = NULL; 4942 4943 /* 4944 * We need to open the channel before we have a FD, 4945 * so that we can get SOCKS header from peer. 4946 */ 4947 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4948 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4949 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4950 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4951 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4952 fatal_fr(r, "channel %i; confirm", c->self); 4953 return c; 4954 } 4955 4956 /* Return CONNECTING socket to remote host:port or local socket path */ 4957 static int 4958 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4959 { 4960 struct ssh_channels *sc = ssh->chanctxt; 4961 struct permission_set *pset = &sc->local_perms; 4962 struct permission *perm; 4963 struct channel_connect cctx; 4964 u_int i, permit_adm = 1; 4965 int sock; 4966 4967 if (pset->num_permitted_admin > 0) { 4968 permit_adm = 0; 4969 for (i = 0; i < pset->num_permitted_admin; i++) { 4970 perm = &pset->permitted_admin[i]; 4971 if (open_match(perm, c->path, c->host_port)) { 4972 permit_adm = 1; 4973 break; 4974 } 4975 } 4976 } 4977 if (!permit_adm) { 4978 debug_f("requested forward not permitted"); 4979 return -1; 4980 } 4981 4982 memset(&cctx, 0, sizeof(cctx)); 4983 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4984 NULL, &cctx, NULL, NULL); 4985 if (sock == -1) 4986 channel_connect_ctx_free(&cctx); 4987 else { 4988 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4989 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4990 c->connect_ctx = cctx; 4991 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4992 } 4993 return sock; 4994 } 4995 4996 /* -- X11 forwarding */ 4997 4998 /* 4999 * Creates an internet domain socket for listening for X11 connections. 5000 * Returns 0 and a suitable display number for the DISPLAY variable 5001 * stored in display_numberp , or -1 if an error occurs. 5002 */ 5003 int 5004 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 5005 int x11_use_localhost, int single_connection, 5006 u_int *display_numberp, int **chanids) 5007 { 5008 Channel *nc = NULL; 5009 int display_number, sock; 5010 u_short port; 5011 struct addrinfo hints, *ai, *aitop; 5012 char strport[NI_MAXSERV]; 5013 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 5014 5015 if (chanids == NULL) 5016 return -1; 5017 5018 for (display_number = x11_display_offset; 5019 display_number < MAX_DISPLAYS; 5020 display_number++) { 5021 port = 6000 + display_number; 5022 memset(&hints, 0, sizeof(hints)); 5023 hints.ai_family = ssh->chanctxt->IPv4or6; 5024 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 5025 hints.ai_socktype = SOCK_STREAM; 5026 snprintf(strport, sizeof strport, "%d", port); 5027 if ((gaierr = getaddrinfo(NULL, strport, 5028 &hints, &aitop)) != 0) { 5029 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 5030 return -1; 5031 } 5032 for (ai = aitop; ai; ai = ai->ai_next) { 5033 if (ai->ai_family != AF_INET && 5034 ai->ai_family != AF_INET6) 5035 continue; 5036 sock = socket(ai->ai_family, ai->ai_socktype, 5037 ai->ai_protocol); 5038 if (sock == -1) { 5039 error("socket: %.100s", strerror(errno)); 5040 freeaddrinfo(aitop); 5041 return -1; 5042 } 5043 set_reuseaddr(sock); 5044 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5045 debug2_f("bind port %d: %.100s", port, 5046 strerror(errno)); 5047 close(sock); 5048 for (n = 0; n < num_socks; n++) 5049 close(socks[n]); 5050 num_socks = 0; 5051 break; 5052 } 5053 socks[num_socks++] = sock; 5054 if (num_socks == NUM_SOCKS) 5055 break; 5056 } 5057 freeaddrinfo(aitop); 5058 if (num_socks > 0) 5059 break; 5060 } 5061 if (display_number >= MAX_DISPLAYS) { 5062 error("Failed to allocate internet-domain X11 display socket."); 5063 return -1; 5064 } 5065 /* Start listening for connections on the socket. */ 5066 for (n = 0; n < num_socks; n++) { 5067 sock = socks[n]; 5068 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5069 error("listen: %.100s", strerror(errno)); 5070 close(sock); 5071 return -1; 5072 } 5073 } 5074 5075 /* Allocate a channel for each socket. */ 5076 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5077 for (n = 0; n < num_socks; n++) { 5078 sock = socks[n]; 5079 /* Is this really necassary? */ 5080 if (hpn_disabled) 5081 nc = channel_new(ssh, "x11-listener", 5082 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5083 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5084 0, "X11 inet listener", 1); 5085 else 5086 nc = channel_new(ssh, "x11 listener", 5087 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5088 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 5089 0, "X11 inet listener", 1); 5090 nc->single_connection = single_connection; 5091 (*chanids)[n] = nc->self; 5092 } 5093 (*chanids)[n] = -1; 5094 5095 /* Return the display number for the DISPLAY environment variable. */ 5096 *display_numberp = display_number; 5097 return 0; 5098 } 5099 5100 static int 5101 connect_local_xsocket(u_int dnr) 5102 { 5103 int sock; 5104 struct sockaddr_un addr; 5105 5106 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5107 if (sock == -1) 5108 error("socket: %.100s", strerror(errno)); 5109 memset(&addr, 0, sizeof(addr)); 5110 addr.sun_family = AF_UNIX; 5111 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 5112 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5113 return sock; 5114 close(sock); 5115 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5116 return -1; 5117 } 5118 5119 int 5120 x11_connect_display(struct ssh *ssh) 5121 { 5122 u_int display_number; 5123 const char *display; 5124 char buf[1024], *cp; 5125 struct addrinfo hints, *ai, *aitop; 5126 char strport[NI_MAXSERV]; 5127 int gaierr, sock = 0; 5128 5129 /* Try to open a socket for the local X server. */ 5130 display = getenv("DISPLAY"); 5131 if (!display) { 5132 error("DISPLAY not set."); 5133 return -1; 5134 } 5135 /* 5136 * Now we decode the value of the DISPLAY variable and make a 5137 * connection to the real X server. 5138 */ 5139 5140 /* 5141 * Check if it is a unix domain socket. Unix domain displays are in 5142 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5143 */ 5144 if (strncmp(display, "unix:", 5) == 0 || 5145 display[0] == ':') { 5146 /* Connect to the unix domain socket. */ 5147 if (sscanf(strrchr(display, ':') + 1, "%u", 5148 &display_number) != 1) { 5149 error("Could not parse display number from DISPLAY: " 5150 "%.100s", display); 5151 return -1; 5152 } 5153 /* Create a socket. */ 5154 sock = connect_local_xsocket(display_number); 5155 if (sock < 0) 5156 return -1; 5157 5158 /* OK, we now have a connection to the display. */ 5159 return sock; 5160 } 5161 /* 5162 * Connect to an inet socket. The DISPLAY value is supposedly 5163 * hostname:d[.s], where hostname may also be numeric IP address. 5164 */ 5165 strlcpy(buf, display, sizeof(buf)); 5166 cp = strchr(buf, ':'); 5167 if (!cp) { 5168 error("Could not find ':' in DISPLAY: %.100s", display); 5169 return -1; 5170 } 5171 *cp = 0; 5172 /* 5173 * buf now contains the host name. But first we parse the 5174 * display number. 5175 */ 5176 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5177 error("Could not parse display number from DISPLAY: %.100s", 5178 display); 5179 return -1; 5180 } 5181 5182 /* Look up the host address */ 5183 memset(&hints, 0, sizeof(hints)); 5184 hints.ai_family = ssh->chanctxt->IPv4or6; 5185 hints.ai_socktype = SOCK_STREAM; 5186 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5187 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5188 error("%.100s: unknown host. (%s)", buf, 5189 ssh_gai_strerror(gaierr)); 5190 return -1; 5191 } 5192 for (ai = aitop; ai; ai = ai->ai_next) { 5193 /* Create a socket. */ 5194 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5195 if (sock == -1) { 5196 debug2("socket: %.100s", strerror(errno)); 5197 continue; 5198 } 5199 /* Connect it to the display. */ 5200 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5201 debug2("connect %.100s port %u: %.100s", buf, 5202 6000 + display_number, strerror(errno)); 5203 close(sock); 5204 continue; 5205 } 5206 /* Success */ 5207 break; 5208 } 5209 freeaddrinfo(aitop); 5210 if (!ai) { 5211 error("connect %.100s port %u: %.100s", buf, 5212 6000 + display_number, strerror(errno)); 5213 return -1; 5214 } 5215 set_nodelay(sock); 5216 return sock; 5217 } 5218 5219 /* 5220 * Requests forwarding of X11 connections, generates fake authentication 5221 * data, and enables authentication spoofing. 5222 * This should be called in the client only. 5223 */ 5224 void 5225 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5226 const char *disp, const char *proto, const char *data, int want_reply) 5227 { 5228 struct ssh_channels *sc = ssh->chanctxt; 5229 u_int data_len = (u_int) strlen(data) / 2; 5230 u_int i, value; 5231 const char *cp; 5232 char *new_data; 5233 int r, screen_number; 5234 5235 if (sc->x11_saved_display == NULL) 5236 sc->x11_saved_display = xstrdup(disp); 5237 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5238 error("x11_request_forwarding_with_spoofing: different " 5239 "$DISPLAY already forwarded"); 5240 return; 5241 } 5242 5243 cp = strchr(disp, ':'); 5244 if (cp) 5245 cp = strchr(cp, '.'); 5246 if (cp) 5247 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5248 else 5249 screen_number = 0; 5250 5251 if (sc->x11_saved_proto == NULL) { 5252 /* Save protocol name. */ 5253 sc->x11_saved_proto = xstrdup(proto); 5254 5255 /* Extract real authentication data. */ 5256 sc->x11_saved_data = xmalloc(data_len); 5257 for (i = 0; i < data_len; i++) { 5258 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5259 fatal("x11_request_forwarding: bad " 5260 "authentication data: %.100s", data); 5261 } 5262 sc->x11_saved_data[i] = value; 5263 } 5264 sc->x11_saved_data_len = data_len; 5265 5266 /* Generate fake data of the same length. */ 5267 sc->x11_fake_data = xmalloc(data_len); 5268 arc4random_buf(sc->x11_fake_data, data_len); 5269 sc->x11_fake_data_len = data_len; 5270 } 5271 5272 /* Convert the fake data into hex. */ 5273 new_data = tohex(sc->x11_fake_data, data_len); 5274 5275 /* Send the request packet. */ 5276 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5277 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5278 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5279 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5280 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5281 (r = sshpkt_send(ssh)) != 0 || 5282 (r = ssh_packet_write_wait(ssh)) < 0) 5283 fatal_fr(r, "send x11-req"); 5284 free(new_data); 5285 } 5286