1 /* $OpenBSD: channels.c,v 1.442 2024/12/05 06:49:26 dtucker Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include "includes.h" 43 44 #include <sys/types.h> 45 #include <sys/stat.h> 46 #include <sys/ioctl.h> 47 #include <sys/un.h> 48 #include <sys/socket.h> 49 #ifdef HAVE_SYS_TIME_H 50 # include <sys/time.h> 51 #endif 52 53 #include <netinet/in.h> 54 #include <arpa/inet.h> 55 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <limits.h> 59 #include <netdb.h> 60 #ifdef HAVE_POLL_H 61 #include <poll.h> 62 #endif 63 #include <stdarg.h> 64 #ifdef HAVE_STDINT_H 65 # include <stdint.h> 66 #endif 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <string.h> 70 #include <termios.h> 71 #include <unistd.h> 72 73 #include "openbsd-compat/sys-queue.h" 74 #include "xmalloc.h" 75 #include "ssh.h" 76 #include "ssh2.h" 77 #include "ssherr.h" 78 #include "sshbuf.h" 79 #include "packet.h" 80 #include "log.h" 81 #include "misc.h" 82 #include "channels.h" 83 #include "compat.h" 84 #include "canohost.h" 85 #include "sshkey.h" 86 #include "authfd.h" 87 #include "pathnames.h" 88 #include "match.h" 89 90 /* XXX remove once we're satisfied there's no lurking bugs */ 91 /* #define DEBUG_CHANNEL_POLL 1 */ 92 93 /* -- agent forwarding */ 94 #define NUM_SOCKS 10 95 96 /* -- X11 forwarding */ 97 /* X11 port for display :0 */ 98 #define X11_BASE_PORT 6000 99 /* Maximum number of fake X11 displays to try. */ 100 #define MAX_DISPLAYS 1000 101 102 /* Per-channel callback for pre/post IO actions */ 103 typedef void chan_fn(struct ssh *, Channel *c); 104 105 /* 106 * Data structure for storing which hosts are permitted for forward requests. 107 * The local sides of any remote forwards are stored in this array to prevent 108 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 109 * network (which might be behind a firewall). 110 */ 111 /* XXX: streamlocal wants a path instead of host:port */ 112 /* Overload host_to_connect; we could just make this match Forward */ 113 /* XXX - can we use listen_host instead of listen_path? */ 114 struct permission { 115 char *host_to_connect; /* Connect to 'host'. */ 116 int port_to_connect; /* Connect to 'port'. */ 117 char *listen_host; /* Remote side should listen address. */ 118 char *listen_path; /* Remote side should listen path. */ 119 int listen_port; /* Remote side should listen port. */ 120 Channel *downstream; /* Downstream mux*/ 121 }; 122 123 /* 124 * Stores the forwarding permission state for a single direction (local or 125 * remote). 126 */ 127 struct permission_set { 128 /* 129 * List of all local permitted host/port pairs to allow for the 130 * user. 131 */ 132 u_int num_permitted_user; 133 struct permission *permitted_user; 134 135 /* 136 * List of all permitted host/port pairs to allow for the admin. 137 */ 138 u_int num_permitted_admin; 139 struct permission *permitted_admin; 140 141 /* 142 * If this is true, all opens/listens are permitted. This is the 143 * case on the server on which we have to trust the client anyway, 144 * and the user could do anything after logging in. 145 */ 146 int all_permitted; 147 }; 148 149 /* Used to record timeouts per channel type */ 150 struct ssh_channel_timeout { 151 char *type_pattern; 152 int timeout_secs; 153 }; 154 155 /* Master structure for channels state */ 156 struct ssh_channels { 157 /* 158 * Pointer to an array containing all allocated channels. The array 159 * is dynamically extended as needed. 160 */ 161 Channel **channels; 162 163 /* 164 * Size of the channel array. All slots of the array must always be 165 * initialized (at least the type field); unused slots set to NULL 166 */ 167 u_int channels_alloc; 168 169 /* 170 * 'channel_pre*' are called just before IO to add any bits 171 * relevant to channels in the c->io_want bitmasks. 172 * 173 * 'channel_post*': perform any appropriate operations for 174 * channels which have c->io_ready events pending. 175 */ 176 chan_fn **channel_pre; 177 chan_fn **channel_post; 178 179 /* -- tcp forwarding */ 180 struct permission_set local_perms; 181 struct permission_set remote_perms; 182 183 /* -- X11 forwarding */ 184 185 /* Saved X11 local (client) display. */ 186 char *x11_saved_display; 187 188 /* Saved X11 authentication protocol name. */ 189 char *x11_saved_proto; 190 191 /* Saved X11 authentication data. This is the real data. */ 192 char *x11_saved_data; 193 u_int x11_saved_data_len; 194 195 /* Deadline after which all X11 connections are refused */ 196 time_t x11_refuse_time; 197 198 /* 199 * Fake X11 authentication data. This is what the server will be 200 * sending us; we should replace any occurrences of this by the 201 * real data. 202 */ 203 u_char *x11_fake_data; 204 u_int x11_fake_data_len; 205 206 /* AF_UNSPEC or AF_INET or AF_INET6 */ 207 int IPv4or6; 208 209 /* Channel timeouts by type */ 210 struct ssh_channel_timeout *timeouts; 211 size_t ntimeouts; 212 /* Global timeout for all OPEN channels */ 213 int global_deadline; 214 time_t lastused; 215 }; 216 217 /* helper */ 218 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 219 static const char *channel_rfwd_bind_host(const char *listen_host); 220 221 /* non-blocking connect helpers */ 222 static int connect_next(struct channel_connect *); 223 static void channel_connect_ctx_free(struct channel_connect *); 224 static Channel *rdynamic_connect_prepare(struct ssh *, char *, 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 #ifdef _AIX 440 /* XXX: Later AIX versions can't push as much data to tty */ 441 c->wfd_isatty = is_tty || isatty(c->wfd); 442 #endif 443 444 /* enable nonblocking mode */ 445 c->restore_block = 0; 446 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 447 /* 448 * Special handling for stdio file descriptors: do not set 449 * non-blocking mode if they are TTYs. Otherwise prepare to 450 * restore their blocking state on exit to avoid interfering 451 * with other programs that follow. 452 */ 453 if (rfd != -1 && !isatty(rfd) && 454 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 455 c->restore_flags[0] = val; 456 c->restore_block |= CHANNEL_RESTORE_RFD; 457 set_nonblock(rfd); 458 } 459 if (wfd != -1 && !isatty(wfd) && 460 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 461 c->restore_flags[1] = val; 462 c->restore_block |= CHANNEL_RESTORE_WFD; 463 set_nonblock(wfd); 464 } 465 if (efd != -1 && !isatty(efd) && 466 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 467 c->restore_flags[2] = val; 468 c->restore_block |= CHANNEL_RESTORE_EFD; 469 set_nonblock(efd); 470 } 471 } else if (nonblock) { 472 if (rfd != -1) 473 set_nonblock(rfd); 474 if (wfd != -1) 475 set_nonblock(wfd); 476 if (efd != -1) 477 set_nonblock(efd); 478 } 479 /* channel might be entering a larval state, so reset global timeout */ 480 channel_set_used_time(ssh, NULL); 481 } 482 483 /* 484 * Allocate a new channel object and set its type and socket. 485 */ 486 Channel * 487 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 488 u_int window, u_int maxpack, int extusage, const char *remote_name, 489 int nonblock) 490 { 491 struct ssh_channels *sc = ssh->chanctxt; 492 u_int i, found = 0; 493 Channel *c; 494 int r; 495 496 /* Try to find a free slot where to put the new channel. */ 497 for (i = 0; i < sc->channels_alloc; i++) { 498 if (sc->channels[i] == NULL) { 499 /* Found a free slot. */ 500 found = i; 501 break; 502 } 503 } 504 if (i >= sc->channels_alloc) { 505 /* 506 * There are no free slots. Take last+1 slot and expand 507 * the array. 508 */ 509 found = sc->channels_alloc; 510 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 511 fatal_f("internal error: channels_alloc %d too big", 512 sc->channels_alloc); 513 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 514 sc->channels_alloc + 10, sizeof(*sc->channels)); 515 sc->channels_alloc += 10; 516 debug2("channel: expanding %d", sc->channels_alloc); 517 } 518 /* Initialize and return new channel. */ 519 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 520 if ((c->input = sshbuf_new()) == NULL || 521 (c->output = sshbuf_new()) == NULL || 522 (c->extended = sshbuf_new()) == NULL) 523 fatal_f("sshbuf_new failed"); 524 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 525 fatal_fr(r, "sshbuf_set_max_size"); 526 c->ostate = CHAN_OUTPUT_OPEN; 527 c->istate = CHAN_INPUT_OPEN; 528 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 529 c->self = found; 530 c->type = type; 531 c->ctype = ctype; 532 c->local_window = window; 533 c->local_window_max = window; 534 c->local_maxpacket = maxpack; 535 c->remote_name = xstrdup(remote_name); 536 c->ctl_chan = -1; 537 c->delayed = 1; /* prevent call to channel_post handler */ 538 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 539 TAILQ_INIT(&c->status_confirms); 540 debug("channel %d: new %s [%s] (inactive timeout: %u)", 541 found, c->ctype, remote_name, c->inactive_deadline); 542 return c; 543 } 544 545 int 546 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 547 { 548 int ret, fd = *fdp; 549 550 if (fd == -1) 551 return 0; 552 553 /* restore blocking */ 554 if (*fdp == c->rfd && 555 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 556 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 557 else if (*fdp == c->wfd && 558 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 559 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 560 else if (*fdp == c->efd && 561 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 562 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 563 564 if (*fdp == c->rfd) { 565 c->io_want &= ~SSH_CHAN_IO_RFD; 566 c->io_ready &= ~SSH_CHAN_IO_RFD; 567 c->rfd = -1; 568 c->pfds[0] = -1; 569 } 570 if (*fdp == c->wfd) { 571 c->io_want &= ~SSH_CHAN_IO_WFD; 572 c->io_ready &= ~SSH_CHAN_IO_WFD; 573 c->wfd = -1; 574 c->pfds[1] = -1; 575 } 576 if (*fdp == c->efd) { 577 c->io_want &= ~SSH_CHAN_IO_EFD; 578 c->io_ready &= ~SSH_CHAN_IO_EFD; 579 c->efd = -1; 580 c->pfds[2] = -1; 581 } 582 if (*fdp == c->sock) { 583 c->io_want &= ~SSH_CHAN_IO_SOCK; 584 c->io_ready &= ~SSH_CHAN_IO_SOCK; 585 c->sock = -1; 586 c->pfds[3] = -1; 587 } 588 589 ret = close(fd); 590 *fdp = -1; /* probably redundant */ 591 return ret; 592 } 593 594 /* Close all channel fd/socket. */ 595 static void 596 channel_close_fds(struct ssh *ssh, Channel *c) 597 { 598 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 599 600 channel_close_fd(ssh, c, &c->sock); 601 if (rfd != sock) 602 channel_close_fd(ssh, c, &c->rfd); 603 if (wfd != sock && wfd != rfd) 604 channel_close_fd(ssh, c, &c->wfd); 605 if (efd != sock && efd != rfd && efd != wfd) 606 channel_close_fd(ssh, c, &c->efd); 607 } 608 609 static void 610 fwd_perm_clear(struct permission *perm) 611 { 612 free(perm->host_to_connect); 613 free(perm->listen_host); 614 free(perm->listen_path); 615 memset(perm, 0, sizeof(*perm)); 616 } 617 618 /* Returns an printable name for the specified forwarding permission list */ 619 static const char * 620 fwd_ident(int who, int where) 621 { 622 if (who == FORWARD_ADM) { 623 if (where == FORWARD_LOCAL) 624 return "admin local"; 625 else if (where == FORWARD_REMOTE) 626 return "admin remote"; 627 } else if (who == FORWARD_USER) { 628 if (where == FORWARD_LOCAL) 629 return "user local"; 630 else if (where == FORWARD_REMOTE) 631 return "user remote"; 632 } 633 fatal("Unknown forward permission list %d/%d", who, where); 634 } 635 636 /* Returns the forwarding permission list for the specified direction */ 637 static struct permission_set * 638 permission_set_get(struct ssh *ssh, int where) 639 { 640 struct ssh_channels *sc = ssh->chanctxt; 641 642 switch (where) { 643 case FORWARD_LOCAL: 644 return &sc->local_perms; 645 break; 646 case FORWARD_REMOTE: 647 return &sc->remote_perms; 648 break; 649 default: 650 fatal_f("invalid forwarding direction %d", where); 651 } 652 } 653 654 /* Returns pointers to the specified forwarding list and its element count */ 655 static void 656 permission_set_get_array(struct ssh *ssh, int who, int where, 657 struct permission ***permpp, u_int **npermpp) 658 { 659 struct permission_set *pset = permission_set_get(ssh, where); 660 661 switch (who) { 662 case FORWARD_USER: 663 *permpp = &pset->permitted_user; 664 *npermpp = &pset->num_permitted_user; 665 break; 666 case FORWARD_ADM: 667 *permpp = &pset->permitted_admin; 668 *npermpp = &pset->num_permitted_admin; 669 break; 670 default: 671 fatal_f("invalid forwarding client %d", who); 672 } 673 } 674 675 /* Adds an entry to the specified forwarding list */ 676 static int 677 permission_set_add(struct ssh *ssh, int who, int where, 678 const char *host_to_connect, int port_to_connect, 679 const char *listen_host, const char *listen_path, int listen_port, 680 Channel *downstream) 681 { 682 struct permission **permp; 683 u_int n, *npermp; 684 685 permission_set_get_array(ssh, who, where, &permp, &npermp); 686 687 if (*npermp >= INT_MAX) 688 fatal_f("%s overflow", fwd_ident(who, where)); 689 690 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 691 n = (*npermp)++; 692 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 693 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 694 (*permp)[n].port_to_connect = port_to_connect; 695 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 696 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 697 (*permp)[n].listen_port = listen_port; 698 (*permp)[n].downstream = downstream; 699 #undef MAYBE_DUP 700 return (int)n; 701 } 702 703 static void 704 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 705 { 706 struct ssh_channels *sc = ssh->chanctxt; 707 struct permission_set *pset = &sc->local_perms; 708 struct permission *perm; 709 int r; 710 u_int i; 711 712 for (i = 0; i < pset->num_permitted_user; i++) { 713 perm = &pset->permitted_user[i]; 714 if (perm->downstream != c) 715 continue; 716 717 /* cancel on the server, since mux client is gone */ 718 debug("channel %d: cleanup remote forward for %s:%u", 719 c->self, perm->listen_host, perm->listen_port); 720 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 721 (r = sshpkt_put_cstring(ssh, 722 "cancel-tcpip-forward")) != 0 || 723 (r = sshpkt_put_u8(ssh, 0)) != 0 || 724 (r = sshpkt_put_cstring(ssh, 725 channel_rfwd_bind_host(perm->listen_host))) != 0 || 726 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 727 (r = sshpkt_send(ssh)) != 0) { 728 fatal_fr(r, "channel %i", c->self); 729 } 730 fwd_perm_clear(perm); /* unregister */ 731 } 732 } 733 734 /* Free the channel and close its fd/socket. */ 735 void 736 channel_free(struct ssh *ssh, Channel *c) 737 { 738 struct ssh_channels *sc = ssh->chanctxt; 739 char *s; 740 u_int i, n; 741 Channel *other; 742 struct channel_confirm *cc; 743 744 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 745 if ((other = sc->channels[i]) == NULL) 746 continue; 747 n++; 748 /* detach from mux client and prepare for closing */ 749 if (c->type == SSH_CHANNEL_MUX_CLIENT && 750 other->type == SSH_CHANNEL_MUX_PROXY && 751 other->mux_ctx == c) { 752 other->mux_ctx = NULL; 753 other->type = SSH_CHANNEL_OPEN; 754 other->istate = CHAN_INPUT_CLOSED; 755 other->ostate = CHAN_OUTPUT_CLOSED; 756 } 757 } 758 debug("channel %d: free: %s, nchannels %u", c->self, 759 c->remote_name ? c->remote_name : "???", n); 760 761 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 762 mux_remove_remote_forwardings(ssh, c); 763 free(c->mux_ctx); 764 c->mux_ctx = NULL; 765 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 766 free(c->mux_ctx); 767 c->mux_ctx = NULL; 768 } 769 770 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 771 s = channel_open_message(ssh); 772 debug3("channel %d: status: %s", c->self, s); 773 free(s); 774 } 775 776 channel_close_fds(ssh, c); 777 sshbuf_free(c->input); 778 sshbuf_free(c->output); 779 sshbuf_free(c->extended); 780 c->input = c->output = c->extended = NULL; 781 free(c->remote_name); 782 c->remote_name = NULL; 783 free(c->path); 784 c->path = NULL; 785 free(c->listening_addr); 786 c->listening_addr = NULL; 787 free(c->xctype); 788 c->xctype = NULL; 789 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 790 if (cc->abandon_cb != NULL) 791 cc->abandon_cb(ssh, c, cc->ctx); 792 TAILQ_REMOVE(&c->status_confirms, cc, entry); 793 freezero(cc, sizeof(*cc)); 794 } 795 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 796 c->filter_cleanup(ssh, c->self, c->filter_ctx); 797 sc->channels[c->self] = NULL; 798 freezero(c, sizeof(*c)); 799 } 800 801 void 802 channel_free_all(struct ssh *ssh) 803 { 804 u_int i; 805 struct ssh_channels *sc = ssh->chanctxt; 806 807 for (i = 0; i < sc->channels_alloc; i++) 808 if (sc->channels[i] != NULL) 809 channel_free(ssh, sc->channels[i]); 810 811 free(sc->channels); 812 sc->channels = NULL; 813 sc->channels_alloc = 0; 814 815 free(sc->x11_saved_display); 816 sc->x11_saved_display = NULL; 817 818 free(sc->x11_saved_proto); 819 sc->x11_saved_proto = NULL; 820 821 free(sc->x11_saved_data); 822 sc->x11_saved_data = NULL; 823 sc->x11_saved_data_len = 0; 824 825 free(sc->x11_fake_data); 826 sc->x11_fake_data = NULL; 827 sc->x11_fake_data_len = 0; 828 } 829 830 /* 831 * Closes the sockets/fds of all channels. This is used to close extra file 832 * descriptors after a fork. 833 */ 834 void 835 channel_close_all(struct ssh *ssh) 836 { 837 u_int i; 838 839 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 840 if (ssh->chanctxt->channels[i] != NULL) 841 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 842 } 843 844 /* 845 * Stop listening to channels. 846 */ 847 void 848 channel_stop_listening(struct ssh *ssh) 849 { 850 u_int i; 851 Channel *c; 852 853 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 854 c = ssh->chanctxt->channels[i]; 855 if (c != NULL) { 856 switch (c->type) { 857 case SSH_CHANNEL_AUTH_SOCKET: 858 case SSH_CHANNEL_PORT_LISTENER: 859 case SSH_CHANNEL_RPORT_LISTENER: 860 case SSH_CHANNEL_X11_LISTENER: 861 case SSH_CHANNEL_UNIX_LISTENER: 862 case SSH_CHANNEL_RUNIX_LISTENER: 863 channel_close_fd(ssh, c, &c->sock); 864 channel_free(ssh, c); 865 break; 866 } 867 } 868 } 869 } 870 871 /* 872 * Returns true if no channel has too much buffered data, and false if one or 873 * more channel is overfull. 874 */ 875 int 876 channel_not_very_much_buffered_data(struct ssh *ssh) 877 { 878 u_int i; 879 u_int maxsize = ssh_packet_get_maxsize(ssh); 880 Channel *c; 881 882 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 883 c = ssh->chanctxt->channels[i]; 884 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 885 continue; 886 if (sshbuf_len(c->output) > maxsize) { 887 debug2("channel %d: big output buffer %zu > %u", 888 c->self, sshbuf_len(c->output), maxsize); 889 return 0; 890 } 891 } 892 return 1; 893 } 894 895 /* Returns true if any channel is still open. */ 896 int 897 channel_still_open(struct ssh *ssh) 898 { 899 u_int i; 900 Channel *c; 901 902 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 903 c = ssh->chanctxt->channels[i]; 904 if (c == NULL) 905 continue; 906 switch (c->type) { 907 case SSH_CHANNEL_X11_LISTENER: 908 case SSH_CHANNEL_PORT_LISTENER: 909 case SSH_CHANNEL_RPORT_LISTENER: 910 case SSH_CHANNEL_MUX_LISTENER: 911 case SSH_CHANNEL_CLOSED: 912 case SSH_CHANNEL_AUTH_SOCKET: 913 case SSH_CHANNEL_DYNAMIC: 914 case SSH_CHANNEL_RDYNAMIC_OPEN: 915 case SSH_CHANNEL_CONNECTING: 916 case SSH_CHANNEL_ZOMBIE: 917 case SSH_CHANNEL_ABANDONED: 918 case SSH_CHANNEL_UNIX_LISTENER: 919 case SSH_CHANNEL_RUNIX_LISTENER: 920 continue; 921 case SSH_CHANNEL_LARVAL: 922 continue; 923 case SSH_CHANNEL_OPENING: 924 case SSH_CHANNEL_OPEN: 925 case SSH_CHANNEL_RDYNAMIC_FINISH: 926 case SSH_CHANNEL_X11_OPEN: 927 case SSH_CHANNEL_MUX_CLIENT: 928 case SSH_CHANNEL_MUX_PROXY: 929 return 1; 930 default: 931 fatal_f("bad channel type %d", c->type); 932 /* NOTREACHED */ 933 } 934 } 935 return 0; 936 } 937 938 /* Returns true if a channel with a TTY is open. */ 939 int 940 channel_tty_open(struct ssh *ssh) 941 { 942 u_int i; 943 Channel *c; 944 945 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 946 c = ssh->chanctxt->channels[i]; 947 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 948 continue; 949 if (c->client_tty) 950 return 1; 951 } 952 return 0; 953 } 954 955 /* Returns the id of an open channel suitable for keepaliving */ 956 int 957 channel_find_open(struct ssh *ssh) 958 { 959 u_int i; 960 Channel *c; 961 962 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 963 c = ssh->chanctxt->channels[i]; 964 if (c == NULL || !c->have_remote_id) 965 continue; 966 switch (c->type) { 967 case SSH_CHANNEL_CLOSED: 968 case SSH_CHANNEL_DYNAMIC: 969 case SSH_CHANNEL_RDYNAMIC_OPEN: 970 case SSH_CHANNEL_RDYNAMIC_FINISH: 971 case SSH_CHANNEL_X11_LISTENER: 972 case SSH_CHANNEL_PORT_LISTENER: 973 case SSH_CHANNEL_RPORT_LISTENER: 974 case SSH_CHANNEL_MUX_LISTENER: 975 case SSH_CHANNEL_MUX_CLIENT: 976 case SSH_CHANNEL_MUX_PROXY: 977 case SSH_CHANNEL_OPENING: 978 case SSH_CHANNEL_CONNECTING: 979 case SSH_CHANNEL_ZOMBIE: 980 case SSH_CHANNEL_ABANDONED: 981 case SSH_CHANNEL_UNIX_LISTENER: 982 case SSH_CHANNEL_RUNIX_LISTENER: 983 continue; 984 case SSH_CHANNEL_LARVAL: 985 case SSH_CHANNEL_AUTH_SOCKET: 986 case SSH_CHANNEL_OPEN: 987 case SSH_CHANNEL_X11_OPEN: 988 return i; 989 default: 990 fatal_f("bad channel type %d", c->type); 991 /* NOTREACHED */ 992 } 993 } 994 return -1; 995 } 996 997 /* Returns the state of the channel's extended usage flag */ 998 const char * 999 channel_format_extended_usage(const Channel *c) 1000 { 1001 if (c->efd == -1) 1002 return "closed"; 1003 1004 switch (c->extended_usage) { 1005 case CHAN_EXTENDED_WRITE: 1006 return "write"; 1007 case CHAN_EXTENDED_READ: 1008 return "read"; 1009 case CHAN_EXTENDED_IGNORE: 1010 return "ignore"; 1011 default: 1012 return "UNKNOWN"; 1013 } 1014 } 1015 1016 static char * 1017 channel_format_status(const Channel *c) 1018 { 1019 char *ret = NULL; 1020 1021 xasprintf(&ret, "t%d [%s] %s%u %s%u i%u/%zu o%u/%zu e[%s]/%zu " 1022 "fd %d/%d/%d sock %d cc %d %s%u io 0x%02x/0x%02x", 1023 c->type, c->xctype != NULL ? c->xctype : c->ctype, 1024 c->have_remote_id ? "r" : "nr", c->remote_id, 1025 c->mux_ctx != NULL ? "m" : "nm", c->mux_downstream_id, 1026 c->istate, sshbuf_len(c->input), 1027 c->ostate, sshbuf_len(c->output), 1028 channel_format_extended_usage(c), sshbuf_len(c->extended), 1029 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 1030 c->have_ctl_child_id ? "c" : "nc", c->ctl_child_id, 1031 c->io_want, c->io_ready); 1032 return ret; 1033 } 1034 1035 /* 1036 * Returns a message describing the currently open forwarded connections, 1037 * suitable for sending to the client. The message contains crlf pairs for 1038 * newlines. 1039 */ 1040 char * 1041 channel_open_message(struct ssh *ssh) 1042 { 1043 struct sshbuf *buf; 1044 Channel *c; 1045 u_int i; 1046 int r; 1047 char *cp, *ret; 1048 1049 if ((buf = sshbuf_new()) == NULL) 1050 fatal_f("sshbuf_new"); 1051 if ((r = sshbuf_putf(buf, 1052 "The following connections are open:\r\n")) != 0) 1053 fatal_fr(r, "sshbuf_putf"); 1054 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1055 c = ssh->chanctxt->channels[i]; 1056 if (c == NULL) 1057 continue; 1058 switch (c->type) { 1059 case SSH_CHANNEL_X11_LISTENER: 1060 case SSH_CHANNEL_PORT_LISTENER: 1061 case SSH_CHANNEL_RPORT_LISTENER: 1062 case SSH_CHANNEL_CLOSED: 1063 case SSH_CHANNEL_AUTH_SOCKET: 1064 case SSH_CHANNEL_ZOMBIE: 1065 case SSH_CHANNEL_ABANDONED: 1066 case SSH_CHANNEL_MUX_LISTENER: 1067 case SSH_CHANNEL_UNIX_LISTENER: 1068 case SSH_CHANNEL_RUNIX_LISTENER: 1069 continue; 1070 case SSH_CHANNEL_LARVAL: 1071 case SSH_CHANNEL_OPENING: 1072 case SSH_CHANNEL_CONNECTING: 1073 case SSH_CHANNEL_DYNAMIC: 1074 case SSH_CHANNEL_RDYNAMIC_OPEN: 1075 case SSH_CHANNEL_RDYNAMIC_FINISH: 1076 case SSH_CHANNEL_OPEN: 1077 case SSH_CHANNEL_X11_OPEN: 1078 case SSH_CHANNEL_MUX_PROXY: 1079 case SSH_CHANNEL_MUX_CLIENT: 1080 cp = channel_format_status(c); 1081 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1082 c->self, c->remote_name, cp)) != 0) { 1083 free(cp); 1084 fatal_fr(r, "sshbuf_putf"); 1085 } 1086 free(cp); 1087 continue; 1088 default: 1089 fatal_f("bad channel type %d", c->type); 1090 /* NOTREACHED */ 1091 } 1092 } 1093 if ((ret = sshbuf_dup_string(buf)) == NULL) 1094 fatal_f("sshbuf_dup_string"); 1095 sshbuf_free(buf); 1096 return ret; 1097 } 1098 1099 static void 1100 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1101 { 1102 int r; 1103 1104 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1105 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1106 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1107 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1108 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1109 fatal_r(r, "%s: channel %i: open", where, c->self); 1110 } 1111 } 1112 1113 void 1114 channel_send_open(struct ssh *ssh, int id) 1115 { 1116 Channel *c = channel_lookup(ssh, id); 1117 int r; 1118 1119 if (c == NULL) { 1120 logit("channel_send_open: %d: bad id", id); 1121 return; 1122 } 1123 debug2("channel %d: send open", id); 1124 open_preamble(ssh, __func__, c, c->ctype); 1125 if ((r = sshpkt_send(ssh)) != 0) 1126 fatal_fr(r, "channel %i", c->self); 1127 } 1128 1129 void 1130 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 1131 { 1132 Channel *c = channel_lookup(ssh, id); 1133 int r; 1134 1135 if (c == NULL) { 1136 logit_f("%d: unknown channel id", id); 1137 return; 1138 } 1139 if (!c->have_remote_id) 1140 fatal_f("channel %d: no remote id", c->self); 1141 1142 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1143 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1144 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1145 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1146 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1147 fatal_fr(r, "channel %i", c->self); 1148 } 1149 } 1150 1151 void 1152 channel_register_status_confirm(struct ssh *ssh, int id, 1153 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1154 { 1155 struct channel_confirm *cc; 1156 Channel *c; 1157 1158 if ((c = channel_lookup(ssh, id)) == NULL) 1159 fatal_f("%d: bad id", id); 1160 1161 cc = xcalloc(1, sizeof(*cc)); 1162 cc->cb = cb; 1163 cc->abandon_cb = abandon_cb; 1164 cc->ctx = ctx; 1165 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1166 } 1167 1168 void 1169 channel_register_open_confirm(struct ssh *ssh, int id, 1170 channel_open_fn *fn, void *ctx) 1171 { 1172 Channel *c = channel_lookup(ssh, id); 1173 1174 if (c == NULL) { 1175 logit_f("%d: bad id", id); 1176 return; 1177 } 1178 c->open_confirm = fn; 1179 c->open_confirm_ctx = ctx; 1180 } 1181 1182 void 1183 channel_register_cleanup(struct ssh *ssh, int id, 1184 channel_callback_fn *fn, int do_close) 1185 { 1186 Channel *c = channel_by_id(ssh, id); 1187 1188 if (c == NULL) { 1189 logit_f("%d: bad id", id); 1190 return; 1191 } 1192 c->detach_user = fn; 1193 c->detach_close = do_close; 1194 } 1195 1196 void 1197 channel_cancel_cleanup(struct ssh *ssh, int id) 1198 { 1199 Channel *c = channel_by_id(ssh, id); 1200 1201 if (c == NULL) { 1202 logit_f("%d: bad id", id); 1203 return; 1204 } 1205 c->detach_user = NULL; 1206 c->detach_close = 0; 1207 } 1208 1209 void 1210 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1211 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1212 { 1213 Channel *c = channel_lookup(ssh, id); 1214 1215 if (c == NULL) { 1216 logit_f("%d: bad id", id); 1217 return; 1218 } 1219 c->input_filter = ifn; 1220 c->output_filter = ofn; 1221 c->filter_ctx = ctx; 1222 c->filter_cleanup = cfn; 1223 } 1224 1225 void 1226 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1227 int extusage, int nonblock, int is_tty, u_int window_max) 1228 { 1229 Channel *c = channel_lookup(ssh, id); 1230 int r; 1231 1232 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1233 fatal("channel_activate for non-larval channel %d.", id); 1234 if (!c->have_remote_id) 1235 fatal_f("channel %d: no remote id", c->self); 1236 1237 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1238 c->type = SSH_CHANNEL_OPEN; 1239 channel_set_used_time(ssh, c); 1240 c->local_window = c->local_window_max = window_max; 1241 1242 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1243 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1244 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1245 (r = sshpkt_send(ssh)) != 0) 1246 fatal_fr(r, "channel %i", c->self); 1247 } 1248 1249 static void 1250 channel_pre_listener(struct ssh *ssh, Channel *c) 1251 { 1252 c->io_want = SSH_CHAN_IO_SOCK_R; 1253 } 1254 1255 static void 1256 channel_pre_connecting(struct ssh *ssh, Channel *c) 1257 { 1258 debug3("channel %d: waiting for connection", c->self); 1259 c->io_want = SSH_CHAN_IO_SOCK_W; 1260 } 1261 1262 static void 1263 channel_pre_open(struct ssh *ssh, Channel *c) 1264 { 1265 c->io_want = 0; 1266 if (c->istate == CHAN_INPUT_OPEN && 1267 c->remote_window > 0 && 1268 sshbuf_len(c->input) < c->remote_window && 1269 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1270 c->io_want |= SSH_CHAN_IO_RFD; 1271 if (c->ostate == CHAN_OUTPUT_OPEN || 1272 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1273 if (sshbuf_len(c->output) > 0) { 1274 c->io_want |= SSH_CHAN_IO_WFD; 1275 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1276 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1277 debug2("channel %d: " 1278 "obuf_empty delayed efd %d/(%zu)", c->self, 1279 c->efd, sshbuf_len(c->extended)); 1280 else 1281 chan_obuf_empty(ssh, c); 1282 } 1283 } 1284 /** XXX check close conditions, too */ 1285 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1286 c->ostate == CHAN_OUTPUT_CLOSED)) { 1287 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1288 sshbuf_len(c->extended) > 0) 1289 c->io_want |= SSH_CHAN_IO_EFD_W; 1290 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1291 (c->extended_usage == CHAN_EXTENDED_READ || 1292 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1293 sshbuf_len(c->extended) < c->remote_window) 1294 c->io_want |= SSH_CHAN_IO_EFD_R; 1295 } 1296 /* XXX: What about efd? races? */ 1297 } 1298 1299 /* 1300 * This is a special state for X11 authentication spoofing. An opened X11 1301 * connection (when authentication spoofing is being done) remains in this 1302 * state until the first packet has been completely read. The authentication 1303 * data in that packet is then substituted by the real data if it matches the 1304 * fake data, and the channel is put into normal mode. 1305 * XXX All this happens at the client side. 1306 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1307 */ 1308 static int 1309 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1310 { 1311 struct ssh_channels *sc = ssh->chanctxt; 1312 u_char *ucp; 1313 u_int proto_len, data_len; 1314 1315 /* Is this being called after the refusal deadline? */ 1316 if (sc->x11_refuse_time != 0 && 1317 monotime() >= sc->x11_refuse_time) { 1318 verbose("Rejected X11 connection after ForwardX11Timeout " 1319 "expired"); 1320 return -1; 1321 } 1322 1323 /* Check if the fixed size part of the packet is in buffer. */ 1324 if (sshbuf_len(b) < 12) 1325 return 0; 1326 1327 /* Parse the lengths of variable-length fields. */ 1328 ucp = sshbuf_mutable_ptr(b); 1329 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1330 proto_len = 256 * ucp[6] + ucp[7]; 1331 data_len = 256 * ucp[8] + ucp[9]; 1332 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1333 proto_len = ucp[6] + 256 * ucp[7]; 1334 data_len = ucp[8] + 256 * ucp[9]; 1335 } else { 1336 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1337 ucp[0]); 1338 return -1; 1339 } 1340 1341 /* Check if the whole packet is in buffer. */ 1342 if (sshbuf_len(b) < 1343 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1344 return 0; 1345 1346 /* Check if authentication protocol matches. */ 1347 if (proto_len != strlen(sc->x11_saved_proto) || 1348 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1349 debug2("X11 connection uses different authentication protocol."); 1350 return -1; 1351 } 1352 /* Check if authentication data matches our fake data. */ 1353 if (data_len != sc->x11_fake_data_len || 1354 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1355 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1356 debug2("X11 auth data does not match fake data."); 1357 return -1; 1358 } 1359 /* Check fake data length */ 1360 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1361 error("X11 fake_data_len %d != saved_data_len %d", 1362 sc->x11_fake_data_len, sc->x11_saved_data_len); 1363 return -1; 1364 } 1365 /* 1366 * Received authentication protocol and data match 1367 * our fake data. Substitute the fake data with real 1368 * data. 1369 */ 1370 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1371 sc->x11_saved_data, sc->x11_saved_data_len); 1372 return 1; 1373 } 1374 1375 void 1376 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1377 { 1378 debug3_f("channel %d: forcibly closing", c->self); 1379 if (c->istate == CHAN_INPUT_OPEN) 1380 chan_read_failed(ssh, c); 1381 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1382 sshbuf_reset(c->input); 1383 chan_ibuf_empty(ssh, c); 1384 } 1385 if (c->ostate == CHAN_OUTPUT_OPEN || 1386 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1387 sshbuf_reset(c->output); 1388 chan_write_failed(ssh, c); 1389 } 1390 if (c->detach_user) 1391 c->detach_user(ssh, c->self, 1, NULL); 1392 if (c->efd != -1) 1393 channel_close_fd(ssh, c, &c->efd); 1394 if (abandon) 1395 c->type = SSH_CHANNEL_ABANDONED; 1396 /* exempt from inactivity timeouts */ 1397 c->inactive_deadline = 0; 1398 c->lastused = 0; 1399 } 1400 1401 static void 1402 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1403 { 1404 int ret = x11_open_helper(ssh, c->output); 1405 1406 /* c->force_drain = 1; */ 1407 1408 if (ret == 1) { 1409 c->type = SSH_CHANNEL_OPEN; 1410 channel_set_used_time(ssh, c); 1411 channel_pre_open(ssh, c); 1412 } else if (ret == -1) { 1413 logit("X11 connection rejected because of wrong " 1414 "authentication."); 1415 debug2("X11 rejected %d i%d/o%d", 1416 c->self, c->istate, c->ostate); 1417 channel_force_close(ssh, c, 0); 1418 } 1419 } 1420 1421 static void 1422 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1423 { 1424 c->io_want = 0; 1425 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1426 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1427 c->io_want |= SSH_CHAN_IO_RFD; 1428 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1429 /* clear buffer immediately (discard any partial packet) */ 1430 sshbuf_reset(c->input); 1431 chan_ibuf_empty(ssh, c); 1432 /* Start output drain. XXX just kill chan? */ 1433 chan_rcvd_oclose(ssh, c); 1434 } 1435 if (c->ostate == CHAN_OUTPUT_OPEN || 1436 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1437 if (sshbuf_len(c->output) > 0) 1438 c->io_want |= SSH_CHAN_IO_WFD; 1439 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1440 chan_obuf_empty(ssh, c); 1441 } 1442 } 1443 1444 /* try to decode a socks4 header */ 1445 static int 1446 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1447 { 1448 const u_char *p; 1449 char *host; 1450 u_int len, have, i, found, need; 1451 char username[256]; 1452 struct { 1453 u_int8_t version; 1454 u_int8_t command; 1455 u_int16_t dest_port; 1456 struct in_addr dest_addr; 1457 } s4_req, s4_rsp; 1458 int r; 1459 1460 debug2("channel %d: decode socks4", c->self); 1461 1462 have = sshbuf_len(input); 1463 len = sizeof(s4_req); 1464 if (have < len) 1465 return 0; 1466 p = sshbuf_ptr(input); 1467 1468 need = 1; 1469 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1470 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1471 debug2("channel %d: socks4a request", c->self); 1472 /* ... and needs an extra string (the hostname) */ 1473 need = 2; 1474 } 1475 /* Check for terminating NUL on the string(s) */ 1476 for (found = 0, i = len; i < have; i++) { 1477 if (p[i] == '\0') { 1478 found++; 1479 if (found == need) 1480 break; 1481 } 1482 if (i > 1024) { 1483 /* the peer is probably sending garbage */ 1484 debug("channel %d: decode socks4: too long", 1485 c->self); 1486 return -1; 1487 } 1488 } 1489 if (found < need) 1490 return 0; 1491 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1492 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1493 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1494 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1495 debug_r(r, "channels %d: decode socks4", c->self); 1496 return -1; 1497 } 1498 have = sshbuf_len(input); 1499 p = sshbuf_ptr(input); 1500 if (memchr(p, '\0', have) == NULL) { 1501 error("channel %d: decode socks4: unterminated user", c->self); 1502 return -1; 1503 } 1504 len = strlen(p); 1505 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1506 len++; /* trailing '\0' */ 1507 strlcpy(username, p, sizeof(username)); 1508 if ((r = sshbuf_consume(input, len)) != 0) 1509 fatal_fr(r, "channel %d: consume", c->self); 1510 free(c->path); 1511 c->path = NULL; 1512 if (need == 1) { /* SOCKS4: one string */ 1513 host = inet_ntoa(s4_req.dest_addr); 1514 c->path = xstrdup(host); 1515 } else { /* SOCKS4A: two strings */ 1516 have = sshbuf_len(input); 1517 p = sshbuf_ptr(input); 1518 if (memchr(p, '\0', have) == NULL) { 1519 error("channel %d: decode socks4a: host not nul " 1520 "terminated", c->self); 1521 return -1; 1522 } 1523 len = strlen(p); 1524 debug2("channel %d: decode socks4a: host %s/%d", 1525 c->self, p, len); 1526 len++; /* trailing '\0' */ 1527 if (len > NI_MAXHOST) { 1528 error("channel %d: hostname \"%.100s\" too long", 1529 c->self, p); 1530 return -1; 1531 } 1532 c->path = xstrdup(p); 1533 if ((r = sshbuf_consume(input, len)) != 0) 1534 fatal_fr(r, "channel %d: consume", c->self); 1535 } 1536 c->host_port = ntohs(s4_req.dest_port); 1537 1538 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1539 c->self, c->path, c->host_port, s4_req.command); 1540 1541 if (s4_req.command != 1) { 1542 debug("channel %d: cannot handle: %s cn %d", 1543 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1544 return -1; 1545 } 1546 s4_rsp.version = 0; /* vn: 0 for reply */ 1547 s4_rsp.command = 90; /* cd: req granted */ 1548 s4_rsp.dest_port = 0; /* ignored */ 1549 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1550 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1551 fatal_fr(r, "channel %d: append reply", c->self); 1552 return 1; 1553 } 1554 1555 /* try to decode a socks5 header */ 1556 #define SSH_SOCKS5_AUTHDONE 0x1000 1557 #define SSH_SOCKS5_NOAUTH 0x00 1558 #define SSH_SOCKS5_IPV4 0x01 1559 #define SSH_SOCKS5_DOMAIN 0x03 1560 #define SSH_SOCKS5_IPV6 0x04 1561 #define SSH_SOCKS5_CONNECT 0x01 1562 #define SSH_SOCKS5_SUCCESS 0x00 1563 1564 static int 1565 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1566 { 1567 /* XXX use get/put_u8 instead of trusting struct padding */ 1568 struct { 1569 u_int8_t version; 1570 u_int8_t command; 1571 u_int8_t reserved; 1572 u_int8_t atyp; 1573 } s5_req, s5_rsp; 1574 u_int16_t dest_port; 1575 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1576 const u_char *p; 1577 u_int have, need, i, found, nmethods, addrlen, af; 1578 int r; 1579 1580 debug2("channel %d: decode socks5", c->self); 1581 p = sshbuf_ptr(input); 1582 if (p[0] != 0x05) 1583 return -1; 1584 have = sshbuf_len(input); 1585 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1586 /* format: ver | nmethods | methods */ 1587 if (have < 2) 1588 return 0; 1589 nmethods = p[1]; 1590 if (have < nmethods + 2) 1591 return 0; 1592 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1593 for (found = 0, i = 2; i < nmethods + 2; i++) { 1594 if (p[i] == SSH_SOCKS5_NOAUTH) { 1595 found = 1; 1596 break; 1597 } 1598 } 1599 if (!found) { 1600 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1601 c->self); 1602 return -1; 1603 } 1604 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1605 fatal_fr(r, "channel %d: consume", c->self); 1606 /* version, method */ 1607 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1608 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1609 fatal_fr(r, "channel %d: append reply", c->self); 1610 c->flags |= SSH_SOCKS5_AUTHDONE; 1611 debug2("channel %d: socks5 auth done", c->self); 1612 return 0; /* need more */ 1613 } 1614 debug2("channel %d: socks5 post auth", c->self); 1615 if (have < sizeof(s5_req)+1) 1616 return 0; /* need more */ 1617 memcpy(&s5_req, p, sizeof(s5_req)); 1618 if (s5_req.version != 0x05 || 1619 s5_req.command != SSH_SOCKS5_CONNECT || 1620 s5_req.reserved != 0x00) { 1621 debug2("channel %d: only socks5 connect supported", c->self); 1622 return -1; 1623 } 1624 switch (s5_req.atyp){ 1625 case SSH_SOCKS5_IPV4: 1626 addrlen = 4; 1627 af = AF_INET; 1628 break; 1629 case SSH_SOCKS5_DOMAIN: 1630 addrlen = p[sizeof(s5_req)]; 1631 af = -1; 1632 break; 1633 case SSH_SOCKS5_IPV6: 1634 addrlen = 16; 1635 af = AF_INET6; 1636 break; 1637 default: 1638 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1639 return -1; 1640 } 1641 need = sizeof(s5_req) + addrlen + 2; 1642 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1643 need++; 1644 if (have < need) 1645 return 0; 1646 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1647 fatal_fr(r, "channel %d: consume", c->self); 1648 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1649 /* host string length */ 1650 if ((r = sshbuf_consume(input, 1)) != 0) 1651 fatal_fr(r, "channel %d: consume", c->self); 1652 } 1653 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1654 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1655 debug_r(r, "channel %d: parse addr/port", c->self); 1656 return -1; 1657 } 1658 dest_addr[addrlen] = '\0'; 1659 free(c->path); 1660 c->path = NULL; 1661 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1662 if (addrlen >= NI_MAXHOST) { 1663 error("channel %d: dynamic request: socks5 hostname " 1664 "\"%.100s\" too long", c->self, dest_addr); 1665 return -1; 1666 } 1667 c->path = xstrdup(dest_addr); 1668 } else { 1669 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1670 return -1; 1671 c->path = xstrdup(ntop); 1672 } 1673 c->host_port = ntohs(dest_port); 1674 1675 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1676 c->self, c->path, c->host_port, s5_req.command); 1677 1678 s5_rsp.version = 0x05; 1679 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1680 s5_rsp.reserved = 0; /* ignored */ 1681 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1682 dest_port = 0; /* ignored */ 1683 1684 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1685 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1686 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1687 fatal_fr(r, "channel %d: append reply", c->self); 1688 return 1; 1689 } 1690 1691 Channel * 1692 channel_connect_stdio_fwd(struct ssh *ssh, 1693 const char *host_to_connect, int port_to_connect, 1694 int in, int out, int nonblock) 1695 { 1696 Channel *c; 1697 1698 debug_f("%s:%d", host_to_connect, port_to_connect); 1699 1700 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1701 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1702 0, "stdio-forward", nonblock); 1703 1704 c->path = xstrdup(host_to_connect); 1705 c->host_port = port_to_connect; 1706 c->listening_port = 0; 1707 c->force_drain = 1; 1708 1709 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1710 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1711 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1712 1713 return c; 1714 } 1715 1716 /* dynamic port forwarding */ 1717 static void 1718 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1719 { 1720 const u_char *p; 1721 u_int have; 1722 int ret; 1723 1724 c->io_want = 0; 1725 have = sshbuf_len(c->input); 1726 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1727 /* sshbuf_dump(c->input, stderr); */ 1728 /* check if the fixed size part of the packet is in buffer. */ 1729 if (have < 3) { 1730 /* need more */ 1731 c->io_want |= SSH_CHAN_IO_RFD; 1732 return; 1733 } 1734 /* try to guess the protocol */ 1735 p = sshbuf_ptr(c->input); 1736 /* XXX sshbuf_peek_u8? */ 1737 switch (p[0]) { 1738 case 0x04: 1739 ret = channel_decode_socks4(c, c->input, c->output); 1740 break; 1741 case 0x05: 1742 ret = channel_decode_socks5(c, c->input, c->output); 1743 break; 1744 default: 1745 ret = -1; 1746 break; 1747 } 1748 if (ret < 0) { 1749 chan_mark_dead(ssh, c); 1750 } else if (ret == 0) { 1751 debug2("channel %d: pre_dynamic: need more", c->self); 1752 /* need more */ 1753 c->io_want |= SSH_CHAN_IO_RFD; 1754 if (sshbuf_len(c->output)) 1755 c->io_want |= SSH_CHAN_IO_WFD; 1756 } else { 1757 /* switch to the next state */ 1758 c->type = SSH_CHANNEL_OPENING; 1759 port_open_helper(ssh, c, "direct-tcpip"); 1760 } 1761 } 1762 1763 /* simulate read-error */ 1764 static void 1765 rdynamic_close(struct ssh *ssh, Channel *c) 1766 { 1767 c->type = SSH_CHANNEL_OPEN; 1768 channel_force_close(ssh, c, 0); 1769 } 1770 1771 /* reverse dynamic port forwarding */ 1772 static void 1773 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1774 { 1775 const u_char *p; 1776 u_int have, len; 1777 int r, ret; 1778 1779 have = sshbuf_len(c->output); 1780 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1781 /* sshbuf_dump(c->output, stderr); */ 1782 /* EOF received */ 1783 if (c->flags & CHAN_EOF_RCVD) { 1784 if ((r = sshbuf_consume(c->output, have)) != 0) 1785 fatal_fr(r, "channel %d: consume", c->self); 1786 rdynamic_close(ssh, c); 1787 return; 1788 } 1789 /* check if the fixed size part of the packet is in buffer. */ 1790 if (have < 3) 1791 return; 1792 /* try to guess the protocol */ 1793 p = sshbuf_ptr(c->output); 1794 switch (p[0]) { 1795 case 0x04: 1796 /* switch input/output for reverse forwarding */ 1797 ret = channel_decode_socks4(c, c->output, c->input); 1798 break; 1799 case 0x05: 1800 ret = channel_decode_socks5(c, c->output, c->input); 1801 break; 1802 default: 1803 ret = -1; 1804 break; 1805 } 1806 if (ret < 0) { 1807 rdynamic_close(ssh, c); 1808 } else if (ret == 0) { 1809 debug2("channel %d: pre_rdynamic: need more", c->self); 1810 /* send socks request to peer */ 1811 len = sshbuf_len(c->input); 1812 if (len > 0 && len < c->remote_window) { 1813 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1814 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1815 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1816 (r = sshpkt_send(ssh)) != 0) { 1817 fatal_fr(r, "channel %i: rdynamic", c->self); 1818 } 1819 if ((r = sshbuf_consume(c->input, len)) != 0) 1820 fatal_fr(r, "channel %d: consume", c->self); 1821 c->remote_window -= len; 1822 } 1823 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1824 /* the connect failed */ 1825 rdynamic_close(ssh, c); 1826 } 1827 } 1828 1829 /* This is our fake X11 server socket. */ 1830 static void 1831 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1832 { 1833 Channel *nc; 1834 struct sockaddr_storage addr; 1835 int r, newsock, oerrno, remote_port; 1836 socklen_t addrlen; 1837 char buf[16384], *remote_ipaddr; 1838 1839 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1840 return; 1841 1842 debug("X11 connection requested."); 1843 addrlen = sizeof(addr); 1844 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1845 if (c->single_connection) { 1846 oerrno = errno; 1847 debug2("single_connection: closing X11 listener."); 1848 channel_close_fd(ssh, c, &c->sock); 1849 chan_mark_dead(ssh, c); 1850 errno = oerrno; 1851 } 1852 if (newsock == -1) { 1853 if (errno != EINTR && errno != EWOULDBLOCK && 1854 errno != ECONNABORTED) 1855 error("accept: %.100s", strerror(errno)); 1856 if (errno == EMFILE || errno == ENFILE) 1857 c->notbefore = monotime() + 1; 1858 return; 1859 } 1860 set_nodelay(newsock); 1861 remote_ipaddr = get_peer_ipaddr(newsock); 1862 remote_port = get_peer_port(newsock); 1863 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1864 remote_ipaddr, remote_port); 1865 1866 nc = channel_new(ssh, "x11-connection", 1867 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1868 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1869 open_preamble(ssh, __func__, nc, "x11"); 1870 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1871 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1872 fatal_fr(r, "channel %i: reply", c->self); 1873 } 1874 if ((r = sshpkt_send(ssh)) != 0) 1875 fatal_fr(r, "channel %i: send", c->self); 1876 free(remote_ipaddr); 1877 } 1878 1879 static void 1880 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1881 { 1882 char *local_ipaddr = get_local_ipaddr(c->sock); 1883 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1884 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1885 int remote_port = get_peer_port(c->sock); 1886 int r; 1887 1888 if (remote_port == -1) { 1889 /* Fake addr/port to appease peers that validate it (Tectia) */ 1890 free(remote_ipaddr); 1891 remote_ipaddr = xstrdup("127.0.0.1"); 1892 remote_port = 65535; 1893 } 1894 1895 free(c->remote_name); 1896 xasprintf(&c->remote_name, 1897 "%s: listening port %d for %.100s port %d, " 1898 "connect from %.200s port %d to %.100s port %d", 1899 rtype, c->listening_port, c->path, c->host_port, 1900 remote_ipaddr, remote_port, local_ipaddr, local_port); 1901 1902 open_preamble(ssh, __func__, c, rtype); 1903 if (strcmp(rtype, "direct-tcpip") == 0) { 1904 /* target host, port */ 1905 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1906 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1907 fatal_fr(r, "channel %i: reply", c->self); 1908 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1909 /* target path */ 1910 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1911 fatal_fr(r, "channel %i: reply", c->self); 1912 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1913 /* listen path */ 1914 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1915 fatal_fr(r, "channel %i: reply", c->self); 1916 } else { 1917 /* listen address, port */ 1918 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1919 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1920 fatal_fr(r, "channel %i: reply", c->self); 1921 } 1922 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1923 /* reserved for future owner/mode info */ 1924 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1925 fatal_fr(r, "channel %i: reply", c->self); 1926 } else { 1927 /* originator host and port */ 1928 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1929 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1930 fatal_fr(r, "channel %i: reply", c->self); 1931 } 1932 if ((r = sshpkt_send(ssh)) != 0) 1933 fatal_fr(r, "channel %i: send", c->self); 1934 free(remote_ipaddr); 1935 free(local_ipaddr); 1936 } 1937 1938 void 1939 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1940 { 1941 ssh->chanctxt->x11_refuse_time = refuse_time; 1942 } 1943 1944 /* 1945 * This socket is listening for connections to a forwarded TCP/IP port. 1946 */ 1947 static void 1948 channel_post_port_listener(struct ssh *ssh, Channel *c) 1949 { 1950 Channel *nc; 1951 struct sockaddr_storage addr; 1952 int newsock, nextstate; 1953 socklen_t addrlen; 1954 char *rtype; 1955 1956 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1957 return; 1958 1959 debug("Connection to port %d forwarding to %.100s port %d requested.", 1960 c->listening_port, c->path, c->host_port); 1961 1962 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1963 nextstate = SSH_CHANNEL_OPENING; 1964 rtype = "forwarded-tcpip"; 1965 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1966 nextstate = SSH_CHANNEL_OPENING; 1967 rtype = "forwarded-streamlocal@openssh.com"; 1968 } else if (c->host_port == PORT_STREAMLOCAL) { 1969 nextstate = SSH_CHANNEL_OPENING; 1970 rtype = "direct-streamlocal@openssh.com"; 1971 } else if (c->host_port == 0) { 1972 nextstate = SSH_CHANNEL_DYNAMIC; 1973 rtype = "dynamic-tcpip"; 1974 } else { 1975 nextstate = SSH_CHANNEL_OPENING; 1976 rtype = "direct-tcpip"; 1977 } 1978 1979 addrlen = sizeof(addr); 1980 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1981 if (newsock == -1) { 1982 if (errno != EINTR && errno != EWOULDBLOCK && 1983 errno != ECONNABORTED) 1984 error("accept: %.100s", strerror(errno)); 1985 if (errno == EMFILE || errno == ENFILE) 1986 c->notbefore = monotime() + 1; 1987 return; 1988 } 1989 if (c->host_port != PORT_STREAMLOCAL) 1990 set_nodelay(newsock); 1991 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1992 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1993 nc->listening_port = c->listening_port; 1994 nc->host_port = c->host_port; 1995 if (c->path != NULL) 1996 nc->path = xstrdup(c->path); 1997 1998 if (nextstate != SSH_CHANNEL_DYNAMIC) 1999 port_open_helper(ssh, nc, rtype); 2000 } 2001 2002 /* 2003 * This is the authentication agent socket listening for connections from 2004 * clients. 2005 */ 2006 static void 2007 channel_post_auth_listener(struct ssh *ssh, Channel *c) 2008 { 2009 Channel *nc; 2010 int r, newsock; 2011 struct sockaddr_storage addr; 2012 socklen_t addrlen; 2013 2014 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2015 return; 2016 2017 addrlen = sizeof(addr); 2018 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2019 if (newsock == -1) { 2020 error("accept from auth socket: %.100s", strerror(errno)); 2021 if (errno == EMFILE || errno == ENFILE) 2022 c->notbefore = monotime() + 1; 2023 return; 2024 } 2025 nc = channel_new(ssh, "agent-connection", 2026 SSH_CHANNEL_OPENING, newsock, newsock, -1, 2027 c->local_window_max, c->local_maxpacket, 2028 0, "accepted auth socket", 1); 2029 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 2030 if ((r = sshpkt_send(ssh)) != 0) 2031 fatal_fr(r, "channel %i", c->self); 2032 } 2033 2034 static void 2035 channel_post_connecting(struct ssh *ssh, Channel *c) 2036 { 2037 int err = 0, sock, isopen, r; 2038 socklen_t sz = sizeof(err); 2039 2040 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2041 return; 2042 if (!c->have_remote_id) 2043 fatal_f("channel %d: no remote id", c->self); 2044 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2045 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2046 2047 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2048 err = errno; 2049 error("getsockopt SO_ERROR failed"); 2050 } 2051 2052 if (err == 0) { 2053 /* Non-blocking connection completed */ 2054 debug("channel %d: connected to %s port %d", 2055 c->self, c->connect_ctx.host, c->connect_ctx.port); 2056 channel_connect_ctx_free(&c->connect_ctx); 2057 c->type = SSH_CHANNEL_OPEN; 2058 channel_set_used_time(ssh, c); 2059 if (isopen) { 2060 /* no message necessary */ 2061 } else { 2062 if ((r = sshpkt_start(ssh, 2063 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2064 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2065 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2066 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2067 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2068 (r = sshpkt_send(ssh)) != 0) 2069 fatal_fr(r, "channel %i open confirm", c->self); 2070 } 2071 return; 2072 } 2073 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2074 return; 2075 2076 /* Non-blocking connection failed */ 2077 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2078 2079 /* Try next address, if any */ 2080 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2081 /* Exhausted all addresses for this destination */ 2082 error("connect_to %.100s port %d: failed.", 2083 c->connect_ctx.host, c->connect_ctx.port); 2084 channel_connect_ctx_free(&c->connect_ctx); 2085 if (isopen) { 2086 rdynamic_close(ssh, c); 2087 } else { 2088 if ((r = sshpkt_start(ssh, 2089 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2090 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2091 (r = sshpkt_put_u32(ssh, 2092 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2093 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2094 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2095 (r = sshpkt_send(ssh)) != 0) 2096 fatal_fr(r, "channel %i: failure", c->self); 2097 chan_mark_dead(ssh, c); 2098 } 2099 } 2100 2101 /* New non-blocking connection in progress */ 2102 close(c->sock); 2103 c->sock = c->rfd = c->wfd = sock; 2104 } 2105 2106 static int 2107 channel_handle_rfd(struct ssh *ssh, Channel *c) 2108 { 2109 char buf[CHAN_RBUF]; 2110 ssize_t len; 2111 int r, force; 2112 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2113 int pty_zeroread = 0; 2114 2115 #ifdef PTY_ZEROREAD 2116 /* Bug on AIX: read(1) can return 0 for a non-closed fd */ 2117 pty_zeroread = c->isatty; 2118 #endif 2119 2120 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2121 2122 if (!force && (c->io_ready & SSH_CHAN_IO_RFD) == 0) 2123 return 1; 2124 if ((avail = sshbuf_avail(c->input)) == 0) 2125 return 1; /* Shouldn't happen */ 2126 2127 /* 2128 * For "simple" channels (i.e. not datagram or filtered), we can 2129 * read directly to the channel buffer. 2130 */ 2131 if (!pty_zeroread && c->input_filter == NULL && !c->datagram) { 2132 /* Only OPEN channels have valid rwin */ 2133 if (c->type == SSH_CHANNEL_OPEN) { 2134 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2135 return 1; /* shouldn't happen */ 2136 if (maxlen > c->remote_window - have) 2137 maxlen = c->remote_window - have; 2138 } 2139 if (maxlen > avail) 2140 maxlen = avail; 2141 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2142 if (errno == EINTR || (!force && 2143 (errno == EAGAIN || errno == EWOULDBLOCK))) 2144 return 1; 2145 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2146 c->self, c->rfd, maxlen, ssh_err(r)); 2147 goto rfail; 2148 } 2149 if (nr != 0) 2150 channel_set_used_time(ssh, c); 2151 return 1; 2152 } 2153 2154 errno = 0; 2155 len = read(c->rfd, buf, sizeof(buf)); 2156 /* fixup AIX zero-length read with errno set to look more like errors */ 2157 if (pty_zeroread && len == 0 && errno != 0) 2158 len = -1; 2159 if (len == -1 && (errno == EINTR || 2160 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 2161 return 1; 2162 if (len < 0 || (!pty_zeroread && len == 0)) { 2163 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2164 c->self, c->rfd, len, 2165 len == 0 ? "closed" : strerror(errno)); 2166 rfail: 2167 if (c->type != SSH_CHANNEL_OPEN) { 2168 debug2("channel %d: not open", c->self); 2169 chan_mark_dead(ssh, c); 2170 return -1; 2171 } else { 2172 chan_read_failed(ssh, c); 2173 } 2174 return -1; 2175 } 2176 channel_set_used_time(ssh, c); 2177 if (c->input_filter != NULL) { 2178 if (c->input_filter(ssh, c, buf, len) == -1) { 2179 debug2("channel %d: filter stops", c->self); 2180 chan_read_failed(ssh, c); 2181 } 2182 } else if (c->datagram) { 2183 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2184 fatal_fr(r, "channel %i: put datagram", c->self); 2185 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2186 fatal_fr(r, "channel %i: put data", c->self); 2187 2188 return 1; 2189 } 2190 2191 static int 2192 channel_handle_wfd(struct ssh *ssh, Channel *c) 2193 { 2194 struct termios tio; 2195 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2196 size_t dlen, olen = 0; 2197 int r, len; 2198 2199 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2200 return 1; 2201 if (sshbuf_len(c->output) == 0) 2202 return 1; 2203 2204 /* Send buffered output data to the socket. */ 2205 olen = sshbuf_len(c->output); 2206 if (c->output_filter != NULL) { 2207 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2208 debug2("channel %d: filter stops", c->self); 2209 if (c->type != SSH_CHANNEL_OPEN) 2210 chan_mark_dead(ssh, c); 2211 else 2212 chan_write_failed(ssh, c); 2213 return -1; 2214 } 2215 } else if (c->datagram) { 2216 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2217 fatal_fr(r, "channel %i: get datagram", c->self); 2218 buf = data; 2219 } else { 2220 buf = data = sshbuf_mutable_ptr(c->output); 2221 dlen = sshbuf_len(c->output); 2222 } 2223 2224 if (c->datagram) { 2225 /* ignore truncated writes, datagrams might get lost */ 2226 len = write(c->wfd, buf, dlen); 2227 free(data); 2228 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2229 errno == EWOULDBLOCK)) 2230 return 1; 2231 if (len <= 0) 2232 goto write_fail; 2233 goto out; 2234 } 2235 2236 #ifdef _AIX 2237 /* XXX: Later AIX versions can't push as much data to tty */ 2238 if (c->wfd_isatty) 2239 dlen = MINIMUM(dlen, 8*1024); 2240 #endif 2241 2242 len = write(c->wfd, buf, dlen); 2243 if (len == -1 && 2244 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 2245 return 1; 2246 if (len <= 0) { 2247 write_fail: 2248 if (c->type != SSH_CHANNEL_OPEN) { 2249 debug2("channel %d: not open", c->self); 2250 chan_mark_dead(ssh, c); 2251 return -1; 2252 } else { 2253 chan_write_failed(ssh, c); 2254 } 2255 return -1; 2256 } 2257 channel_set_used_time(ssh, c); 2258 #ifndef BROKEN_TCGETATTR_ICANON 2259 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2260 if (tcgetattr(c->wfd, &tio) == 0 && 2261 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2262 /* 2263 * Simulate echo to reduce the impact of 2264 * traffic analysis. We need to match the 2265 * size of a SSH2_MSG_CHANNEL_DATA message 2266 * (4 byte channel id + buf) 2267 */ 2268 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2269 (r = sshpkt_send(ssh)) != 0) 2270 fatal_fr(r, "channel %i: ignore", c->self); 2271 } 2272 } 2273 #endif /* BROKEN_TCGETATTR_ICANON */ 2274 if ((r = sshbuf_consume(c->output, len)) != 0) 2275 fatal_fr(r, "channel %i: consume", c->self); 2276 out: 2277 c->local_consumed += olen - sshbuf_len(c->output); 2278 2279 return 1; 2280 } 2281 2282 static int 2283 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2284 { 2285 int r; 2286 ssize_t len; 2287 2288 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2289 return 1; 2290 if (sshbuf_len(c->extended) == 0) 2291 return 1; 2292 2293 len = write(c->efd, sshbuf_ptr(c->extended), 2294 sshbuf_len(c->extended)); 2295 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2296 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2297 errno == EWOULDBLOCK)) 2298 return 1; 2299 if (len <= 0) { 2300 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2301 channel_close_fd(ssh, c, &c->efd); 2302 } else { 2303 if ((r = sshbuf_consume(c->extended, len)) != 0) 2304 fatal_fr(r, "channel %i: consume", c->self); 2305 c->local_consumed += len; 2306 channel_set_used_time(ssh, c); 2307 } 2308 return 1; 2309 } 2310 2311 static int 2312 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2313 { 2314 char buf[CHAN_RBUF]; 2315 ssize_t len; 2316 int r, force; 2317 2318 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2319 2320 if (!force && (c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2321 return 1; 2322 2323 len = read(c->efd, buf, sizeof(buf)); 2324 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2325 if (len == -1 && (errno == EINTR || ((errno == EAGAIN || 2326 errno == EWOULDBLOCK) && !force))) 2327 return 1; 2328 if (len <= 0) { 2329 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2330 channel_close_fd(ssh, c, &c->efd); 2331 return 1; 2332 } 2333 channel_set_used_time(ssh, c); 2334 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2335 debug3("channel %d: discard efd", c->self); 2336 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2337 fatal_fr(r, "channel %i: append", c->self); 2338 return 1; 2339 } 2340 2341 static int 2342 channel_handle_efd(struct ssh *ssh, Channel *c) 2343 { 2344 if (c->efd == -1) 2345 return 1; 2346 2347 /** XXX handle drain efd, too */ 2348 2349 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2350 return channel_handle_efd_write(ssh, c); 2351 else if (c->extended_usage == CHAN_EXTENDED_READ || 2352 c->extended_usage == CHAN_EXTENDED_IGNORE) 2353 return channel_handle_efd_read(ssh, c); 2354 2355 return 1; 2356 } 2357 2358 static int 2359 channel_check_window(struct ssh *ssh, Channel *c) 2360 { 2361 int r; 2362 2363 if (c->type == SSH_CHANNEL_OPEN && 2364 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2365 ((c->local_window_max - c->local_window > 2366 c->local_maxpacket*3) || 2367 c->local_window < c->local_window_max/2) && 2368 c->local_consumed > 0) { 2369 if (!c->have_remote_id) 2370 fatal_f("channel %d: no remote id", c->self); 2371 if ((r = sshpkt_start(ssh, 2372 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2373 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2374 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2375 (r = sshpkt_send(ssh)) != 0) { 2376 fatal_fr(r, "channel %i", c->self); 2377 } 2378 debug2("channel %d: window %d sent adjust %d", c->self, 2379 c->local_window, c->local_consumed); 2380 c->local_window += c->local_consumed; 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 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 3723 /* 3724 * Determine whether or not a port forward listens to loopback, the 3725 * specified address or wildcard. On the client, a specified bind 3726 * address will always override gateway_ports. On the server, a 3727 * gateway_ports of 1 (``yes'') will override the client's specification 3728 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3729 * will bind to whatever address the client asked for. 3730 * 3731 * Special-case listen_addrs are: 3732 * 3733 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3734 * "" (empty string), "*" -> wildcard v4/v6 3735 * "localhost" -> loopback v4/v6 3736 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3737 */ 3738 static const char * 3739 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3740 int is_client, struct ForwardOptions *fwd_opts) 3741 { 3742 const char *addr = NULL; 3743 int wildcard = 0; 3744 3745 if (listen_addr == NULL) { 3746 /* No address specified: default to gateway_ports setting */ 3747 if (fwd_opts->gateway_ports) 3748 wildcard = 1; 3749 } else if (fwd_opts->gateway_ports || is_client) { 3750 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3751 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3752 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3753 (!is_client && fwd_opts->gateway_ports == 1)) { 3754 wildcard = 1; 3755 /* 3756 * Notify client if they requested a specific listen 3757 * address and it was overridden. 3758 */ 3759 if (*listen_addr != '\0' && 3760 strcmp(listen_addr, "0.0.0.0") != 0 && 3761 strcmp(listen_addr, "*") != 0) { 3762 ssh_packet_send_debug(ssh, 3763 "Forwarding listen address " 3764 "\"%s\" overridden by server " 3765 "GatewayPorts", listen_addr); 3766 } 3767 } else if (strcmp(listen_addr, "localhost") != 0 || 3768 strcmp(listen_addr, "127.0.0.1") == 0 || 3769 strcmp(listen_addr, "::1") == 0) { 3770 /* 3771 * Accept explicit localhost address when 3772 * GatewayPorts=yes. The "localhost" hostname is 3773 * deliberately skipped here so it will listen on all 3774 * available local address families. 3775 */ 3776 addr = listen_addr; 3777 } 3778 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3779 strcmp(listen_addr, "::1") == 0) { 3780 /* 3781 * If a specific IPv4/IPv6 localhost address has been 3782 * requested then accept it even if gateway_ports is in 3783 * effect. This allows the client to prefer IPv4 or IPv6. 3784 */ 3785 addr = listen_addr; 3786 } 3787 if (wildcardp != NULL) 3788 *wildcardp = wildcard; 3789 return addr; 3790 } 3791 3792 static int 3793 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3794 struct Forward *fwd, int *allocated_listen_port, 3795 struct ForwardOptions *fwd_opts) 3796 { 3797 Channel *c; 3798 int sock, r, success = 0, wildcard = 0, is_client; 3799 struct addrinfo hints, *ai, *aitop; 3800 const char *host, *addr; 3801 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3802 in_port_t *lport_p; 3803 3804 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3805 3806 if (is_client && fwd->connect_path != NULL) { 3807 host = fwd->connect_path; 3808 } else { 3809 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3810 fwd->listen_host : fwd->connect_host; 3811 if (host == NULL) { 3812 error("No forward host name."); 3813 return 0; 3814 } 3815 if (strlen(host) >= NI_MAXHOST) { 3816 error("Forward host name too long."); 3817 return 0; 3818 } 3819 } 3820 3821 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3822 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3823 is_client, fwd_opts); 3824 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3825 (addr == NULL) ? "NULL" : addr); 3826 3827 /* 3828 * getaddrinfo returns a loopback address if the hostname is 3829 * set to NULL and hints.ai_flags is not AI_PASSIVE 3830 */ 3831 memset(&hints, 0, sizeof(hints)); 3832 hints.ai_family = ssh->chanctxt->IPv4or6; 3833 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3834 hints.ai_socktype = SOCK_STREAM; 3835 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3836 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3837 if (addr == NULL) { 3838 /* This really shouldn't happen */ 3839 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3840 ssh_gai_strerror(r)); 3841 } else { 3842 error_f("getaddrinfo(%.64s): %s", addr, 3843 ssh_gai_strerror(r)); 3844 } 3845 return 0; 3846 } 3847 if (allocated_listen_port != NULL) 3848 *allocated_listen_port = 0; 3849 for (ai = aitop; ai; ai = ai->ai_next) { 3850 switch (ai->ai_family) { 3851 case AF_INET: 3852 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3853 sin_port; 3854 break; 3855 case AF_INET6: 3856 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3857 sin6_port; 3858 break; 3859 default: 3860 continue; 3861 } 3862 /* 3863 * If allocating a port for -R forwards, then use the 3864 * same port for all address families. 3865 */ 3866 if (type == SSH_CHANNEL_RPORT_LISTENER && 3867 fwd->listen_port == 0 && allocated_listen_port != NULL && 3868 *allocated_listen_port > 0) 3869 *lport_p = htons(*allocated_listen_port); 3870 3871 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3872 strport, sizeof(strport), 3873 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3874 error_f("getnameinfo failed"); 3875 continue; 3876 } 3877 /* Create a port to listen for the host. */ 3878 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3879 if (sock == -1) { 3880 /* this is no error since kernel may not support ipv6 */ 3881 verbose("socket [%s]:%s: %.100s", ntop, strport, 3882 strerror(errno)); 3883 continue; 3884 } 3885 3886 set_reuseaddr(sock); 3887 if (ai->ai_family == AF_INET6) 3888 sock_set_v6only(sock); 3889 3890 debug("Local forwarding listening on %s port %s.", 3891 ntop, strport); 3892 3893 /* Bind the socket to the address. */ 3894 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3895 /* 3896 * address can be in if use ipv6 address is 3897 * already bound 3898 */ 3899 if (!ai->ai_next) 3900 error("bind [%s]:%s: %.100s", 3901 ntop, strport, strerror(errno)); 3902 else 3903 verbose("bind [%s]:%s: %.100s", 3904 ntop, strport, strerror(errno)); 3905 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 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3932 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3933 0, "port listener", 1); 3934 c->path = xstrdup(host); 3935 c->host_port = fwd->connect_port; 3936 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3937 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3938 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3939 c->listening_port = *allocated_listen_port; 3940 else 3941 c->listening_port = fwd->listen_port; 3942 success = 1; 3943 } 3944 if (success == 0) 3945 error_f("cannot listen to port: %d", fwd->listen_port); 3946 freeaddrinfo(aitop); 3947 return success; 3948 } 3949 3950 static int 3951 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3952 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3953 { 3954 struct sockaddr_un sunaddr; 3955 const char *path; 3956 Channel *c; 3957 int port, sock; 3958 mode_t omask; 3959 3960 switch (type) { 3961 case SSH_CHANNEL_UNIX_LISTENER: 3962 if (fwd->connect_path != NULL) { 3963 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3964 error("Local connecting path too long: %s", 3965 fwd->connect_path); 3966 return 0; 3967 } 3968 path = fwd->connect_path; 3969 port = PORT_STREAMLOCAL; 3970 } else { 3971 if (fwd->connect_host == NULL) { 3972 error("No forward host name."); 3973 return 0; 3974 } 3975 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3976 error("Forward host name too long."); 3977 return 0; 3978 } 3979 path = fwd->connect_host; 3980 port = fwd->connect_port; 3981 } 3982 break; 3983 case SSH_CHANNEL_RUNIX_LISTENER: 3984 path = fwd->listen_path; 3985 port = PORT_STREAMLOCAL; 3986 break; 3987 default: 3988 error_f("unexpected channel type %d", type); 3989 return 0; 3990 } 3991 3992 if (fwd->listen_path == NULL) { 3993 error("No forward path name."); 3994 return 0; 3995 } 3996 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3997 error("Local listening path too long: %s", fwd->listen_path); 3998 return 0; 3999 } 4000 4001 debug3_f("type %d path %s", type, fwd->listen_path); 4002 4003 /* Start a Unix domain listener. */ 4004 omask = umask(fwd_opts->streamlocal_bind_mask); 4005 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 4006 fwd_opts->streamlocal_bind_unlink); 4007 umask(omask); 4008 if (sock < 0) 4009 return 0; 4010 4011 debug("Local forwarding listening on path %s.", fwd->listen_path); 4012 4013 /* Allocate a channel number for the socket. */ 4014 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 4015 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 4016 0, "unix listener", 1); 4017 c->path = xstrdup(path); 4018 c->host_port = port; 4019 c->listening_port = PORT_STREAMLOCAL; 4020 c->listening_addr = xstrdup(fwd->listen_path); 4021 return 1; 4022 } 4023 4024 static int 4025 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 4026 const char *host, u_short port) 4027 { 4028 u_int i; 4029 int found = 0; 4030 4031 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4032 Channel *c = ssh->chanctxt->channels[i]; 4033 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 4034 continue; 4035 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 4036 debug2_f("close channel %d", i); 4037 channel_free(ssh, c); 4038 found = 1; 4039 } 4040 } 4041 4042 return found; 4043 } 4044 4045 static int 4046 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 4047 { 4048 u_int i; 4049 int found = 0; 4050 4051 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4052 Channel *c = ssh->chanctxt->channels[i]; 4053 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 4054 continue; 4055 if (c->path == NULL) 4056 continue; 4057 if (strcmp(c->path, path) == 0) { 4058 debug2_f("close channel %d", i); 4059 channel_free(ssh, c); 4060 found = 1; 4061 } 4062 } 4063 4064 return found; 4065 } 4066 4067 int 4068 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4069 { 4070 if (fwd->listen_path != NULL) { 4071 return channel_cancel_rport_listener_streamlocal(ssh, 4072 fwd->listen_path); 4073 } else { 4074 return channel_cancel_rport_listener_tcpip(ssh, 4075 fwd->listen_host, fwd->listen_port); 4076 } 4077 } 4078 4079 static int 4080 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4081 const char *lhost, u_short lport, int cport, 4082 struct ForwardOptions *fwd_opts) 4083 { 4084 u_int i; 4085 int found = 0; 4086 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4087 4088 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4089 Channel *c = ssh->chanctxt->channels[i]; 4090 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4091 continue; 4092 if (c->listening_port != lport) 4093 continue; 4094 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4095 /* skip dynamic forwardings */ 4096 if (c->host_port == 0) 4097 continue; 4098 } else { 4099 if (c->host_port != cport) 4100 continue; 4101 } 4102 if ((c->listening_addr == NULL && addr != NULL) || 4103 (c->listening_addr != NULL && addr == NULL)) 4104 continue; 4105 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4106 debug2_f("close channel %d", i); 4107 channel_free(ssh, c); 4108 found = 1; 4109 } 4110 } 4111 4112 return found; 4113 } 4114 4115 static int 4116 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4117 { 4118 u_int i; 4119 int found = 0; 4120 4121 if (path == NULL) { 4122 error_f("no path specified."); 4123 return 0; 4124 } 4125 4126 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4127 Channel *c = ssh->chanctxt->channels[i]; 4128 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4129 continue; 4130 if (c->listening_addr == NULL) 4131 continue; 4132 if (strcmp(c->listening_addr, path) == 0) { 4133 debug2_f("close channel %d", i); 4134 channel_free(ssh, c); 4135 found = 1; 4136 } 4137 } 4138 4139 return found; 4140 } 4141 4142 int 4143 channel_cancel_lport_listener(struct ssh *ssh, 4144 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4145 { 4146 if (fwd->listen_path != NULL) { 4147 return channel_cancel_lport_listener_streamlocal(ssh, 4148 fwd->listen_path); 4149 } else { 4150 return channel_cancel_lport_listener_tcpip(ssh, 4151 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4152 } 4153 } 4154 4155 /* protocol local port fwd, used by ssh */ 4156 int 4157 channel_setup_local_fwd_listener(struct ssh *ssh, 4158 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4159 { 4160 if (fwd->listen_path != NULL) { 4161 return channel_setup_fwd_listener_streamlocal(ssh, 4162 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4163 } else { 4164 return channel_setup_fwd_listener_tcpip(ssh, 4165 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4166 } 4167 } 4168 4169 /* Matches a remote forwarding permission against a requested forwarding */ 4170 static int 4171 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4172 { 4173 int ret; 4174 char *lhost; 4175 4176 /* XXX add ACLs for streamlocal */ 4177 if (fwd->listen_path != NULL) 4178 return 1; 4179 4180 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4181 return 0; 4182 4183 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4184 allowed_open->listen_port != fwd->listen_port) 4185 return 0; 4186 4187 /* Match hostnames case-insensitively */ 4188 lhost = xstrdup(fwd->listen_host); 4189 lowercase(lhost); 4190 ret = match_pattern(lhost, allowed_open->listen_host); 4191 free(lhost); 4192 4193 return ret; 4194 } 4195 4196 /* Checks whether a requested remote forwarding is permitted */ 4197 static int 4198 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4199 { 4200 struct ssh_channels *sc = ssh->chanctxt; 4201 struct permission_set *pset = &sc->remote_perms; 4202 u_int i, permit, permit_adm = 1; 4203 struct permission *perm; 4204 4205 /* XXX apply GatewayPorts override before checking? */ 4206 4207 permit = pset->all_permitted; 4208 if (!permit) { 4209 for (i = 0; i < pset->num_permitted_user; i++) { 4210 perm = &pset->permitted_user[i]; 4211 if (remote_open_match(perm, fwd)) { 4212 permit = 1; 4213 break; 4214 } 4215 } 4216 } 4217 4218 if (pset->num_permitted_admin > 0) { 4219 permit_adm = 0; 4220 for (i = 0; i < pset->num_permitted_admin; i++) { 4221 perm = &pset->permitted_admin[i]; 4222 if (remote_open_match(perm, fwd)) { 4223 permit_adm = 1; 4224 break; 4225 } 4226 } 4227 } 4228 4229 return permit && permit_adm; 4230 } 4231 4232 /* protocol v2 remote port fwd, used by sshd */ 4233 int 4234 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4235 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4236 { 4237 if (!check_rfwd_permission(ssh, fwd)) { 4238 ssh_packet_send_debug(ssh, "port forwarding refused"); 4239 if (fwd->listen_path != NULL) 4240 /* XXX always allowed, see remote_open_match() */ 4241 logit("Received request from %.100s port %d to " 4242 "remote forward to path \"%.100s\", " 4243 "but the request was denied.", 4244 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4245 fwd->listen_path); 4246 else if(fwd->listen_host != NULL) 4247 logit("Received request from %.100s port %d to " 4248 "remote forward to host %.100s port %d, " 4249 "but the request was denied.", 4250 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4251 fwd->listen_host, fwd->listen_port ); 4252 else 4253 logit("Received request from %.100s port %d to remote " 4254 "forward, but the request was denied.", 4255 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4256 return 0; 4257 } 4258 if (fwd->listen_path != NULL) { 4259 return channel_setup_fwd_listener_streamlocal(ssh, 4260 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4261 } else { 4262 return channel_setup_fwd_listener_tcpip(ssh, 4263 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4264 fwd_opts); 4265 } 4266 } 4267 4268 /* 4269 * Translate the requested rfwd listen host to something usable for 4270 * this server. 4271 */ 4272 static const char * 4273 channel_rfwd_bind_host(const char *listen_host) 4274 { 4275 if (listen_host == NULL) { 4276 return "localhost"; 4277 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4278 return ""; 4279 } else 4280 return listen_host; 4281 } 4282 4283 /* 4284 * Initiate forwarding of connections to port "port" on remote host through 4285 * the secure channel to host:port from local side. 4286 * Returns handle (index) for updating the dynamic listen port with 4287 * channel_update_permission(). 4288 */ 4289 int 4290 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4291 { 4292 int r, success = 0, idx = -1; 4293 const char *host_to_connect, *listen_host, *listen_path; 4294 int port_to_connect, listen_port; 4295 4296 /* Send the forward request to the remote side. */ 4297 if (fwd->listen_path != NULL) { 4298 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4299 (r = sshpkt_put_cstring(ssh, 4300 "streamlocal-forward@openssh.com")) != 0 || 4301 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4302 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4303 (r = sshpkt_send(ssh)) != 0 || 4304 (r = ssh_packet_write_wait(ssh)) != 0) 4305 fatal_fr(r, "request streamlocal"); 4306 } else { 4307 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4308 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4309 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4310 (r = sshpkt_put_cstring(ssh, 4311 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4312 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4313 (r = sshpkt_send(ssh)) != 0 || 4314 (r = ssh_packet_write_wait(ssh)) != 0) 4315 fatal_fr(r, "request tcpip-forward"); 4316 } 4317 /* Assume that server accepts the request */ 4318 success = 1; 4319 if (success) { 4320 /* Record that connection to this host/port is permitted. */ 4321 host_to_connect = listen_host = listen_path = NULL; 4322 port_to_connect = listen_port = 0; 4323 if (fwd->connect_path != NULL) { 4324 host_to_connect = fwd->connect_path; 4325 port_to_connect = PORT_STREAMLOCAL; 4326 } else { 4327 host_to_connect = fwd->connect_host; 4328 port_to_connect = fwd->connect_port; 4329 } 4330 if (fwd->listen_path != NULL) { 4331 listen_path = fwd->listen_path; 4332 listen_port = PORT_STREAMLOCAL; 4333 } else { 4334 listen_host = fwd->listen_host; 4335 listen_port = fwd->listen_port; 4336 } 4337 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4338 host_to_connect, port_to_connect, 4339 listen_host, listen_path, listen_port, NULL); 4340 } 4341 return idx; 4342 } 4343 4344 static int 4345 open_match(struct permission *allowed_open, const char *requestedhost, 4346 int requestedport) 4347 { 4348 if (allowed_open->host_to_connect == NULL) 4349 return 0; 4350 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4351 allowed_open->port_to_connect != requestedport) 4352 return 0; 4353 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4354 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4355 return 0; 4356 return 1; 4357 } 4358 4359 /* 4360 * Note that in the listen host/port case 4361 * we don't support FWD_PERMIT_ANY_PORT and 4362 * need to translate between the configured-host (listen_host) 4363 * and what we've sent to the remote server (channel_rfwd_bind_host) 4364 */ 4365 static int 4366 open_listen_match_tcpip(struct permission *allowed_open, 4367 const char *requestedhost, u_short requestedport, int translate) 4368 { 4369 const char *allowed_host; 4370 4371 if (allowed_open->host_to_connect == NULL) 4372 return 0; 4373 if (allowed_open->listen_port != requestedport) 4374 return 0; 4375 if (!translate && allowed_open->listen_host == NULL && 4376 requestedhost == NULL) 4377 return 1; 4378 allowed_host = translate ? 4379 channel_rfwd_bind_host(allowed_open->listen_host) : 4380 allowed_open->listen_host; 4381 if (allowed_host == NULL || requestedhost == NULL || 4382 strcmp(allowed_host, requestedhost) != 0) 4383 return 0; 4384 return 1; 4385 } 4386 4387 static int 4388 open_listen_match_streamlocal(struct permission *allowed_open, 4389 const char *requestedpath) 4390 { 4391 if (allowed_open->host_to_connect == NULL) 4392 return 0; 4393 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4394 return 0; 4395 if (allowed_open->listen_path == NULL || 4396 strcmp(allowed_open->listen_path, requestedpath) != 0) 4397 return 0; 4398 return 1; 4399 } 4400 4401 /* 4402 * Request cancellation of remote forwarding of connection host:port from 4403 * local side. 4404 */ 4405 static int 4406 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4407 const char *host, u_short port) 4408 { 4409 struct ssh_channels *sc = ssh->chanctxt; 4410 struct permission_set *pset = &sc->local_perms; 4411 int r; 4412 u_int i; 4413 struct permission *perm = NULL; 4414 4415 for (i = 0; i < pset->num_permitted_user; i++) { 4416 perm = &pset->permitted_user[i]; 4417 if (open_listen_match_tcpip(perm, host, port, 0)) 4418 break; 4419 perm = NULL; 4420 } 4421 if (perm == NULL) { 4422 debug_f("requested forward not found"); 4423 return -1; 4424 } 4425 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4426 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4427 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4428 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4429 (r = sshpkt_put_u32(ssh, port)) != 0 || 4430 (r = sshpkt_send(ssh)) != 0) 4431 fatal_fr(r, "send cancel"); 4432 4433 fwd_perm_clear(perm); /* unregister */ 4434 4435 return 0; 4436 } 4437 4438 /* 4439 * Request cancellation of remote forwarding of Unix domain socket 4440 * path from local side. 4441 */ 4442 static int 4443 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4444 { 4445 struct ssh_channels *sc = ssh->chanctxt; 4446 struct permission_set *pset = &sc->local_perms; 4447 int r; 4448 u_int i; 4449 struct permission *perm = NULL; 4450 4451 for (i = 0; i < pset->num_permitted_user; i++) { 4452 perm = &pset->permitted_user[i]; 4453 if (open_listen_match_streamlocal(perm, path)) 4454 break; 4455 perm = NULL; 4456 } 4457 if (perm == NULL) { 4458 debug_f("requested forward not found"); 4459 return -1; 4460 } 4461 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4462 (r = sshpkt_put_cstring(ssh, 4463 "cancel-streamlocal-forward@openssh.com")) != 0 || 4464 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4465 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4466 (r = sshpkt_send(ssh)) != 0) 4467 fatal_fr(r, "send cancel"); 4468 4469 fwd_perm_clear(perm); /* unregister */ 4470 4471 return 0; 4472 } 4473 4474 /* 4475 * Request cancellation of remote forwarding of a connection from local side. 4476 */ 4477 int 4478 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4479 { 4480 if (fwd->listen_path != NULL) { 4481 return channel_request_rforward_cancel_streamlocal(ssh, 4482 fwd->listen_path); 4483 } else { 4484 return channel_request_rforward_cancel_tcpip(ssh, 4485 fwd->listen_host, 4486 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4487 } 4488 } 4489 4490 /* 4491 * Permits opening to any host/port if permitted_user[] is empty. This is 4492 * usually called by the server, because the user could connect to any port 4493 * anyway, and the server has no way to know but to trust the client anyway. 4494 */ 4495 void 4496 channel_permit_all(struct ssh *ssh, int where) 4497 { 4498 struct permission_set *pset = permission_set_get(ssh, where); 4499 4500 if (pset->num_permitted_user == 0) 4501 pset->all_permitted = 1; 4502 } 4503 4504 /* 4505 * Permit the specified host/port for forwarding. 4506 */ 4507 void 4508 channel_add_permission(struct ssh *ssh, int who, int where, 4509 char *host, int port) 4510 { 4511 int local = where == FORWARD_LOCAL; 4512 struct permission_set *pset = permission_set_get(ssh, where); 4513 4514 debug("allow %s forwarding to host %s port %d", 4515 fwd_ident(who, where), host, port); 4516 /* 4517 * Remote forwards set listen_host/port, local forwards set 4518 * host/port_to_connect. 4519 */ 4520 permission_set_add(ssh, who, where, 4521 local ? host : 0, local ? port : 0, 4522 local ? NULL : host, NULL, local ? 0 : port, NULL); 4523 pset->all_permitted = 0; 4524 } 4525 4526 /* 4527 * Administratively disable forwarding. 4528 */ 4529 void 4530 channel_disable_admin(struct ssh *ssh, int where) 4531 { 4532 channel_clear_permission(ssh, FORWARD_ADM, where); 4533 permission_set_add(ssh, FORWARD_ADM, where, 4534 NULL, 0, NULL, NULL, 0, NULL); 4535 } 4536 4537 /* 4538 * Clear a list of permitted opens. 4539 */ 4540 void 4541 channel_clear_permission(struct ssh *ssh, int who, int where) 4542 { 4543 struct permission **permp; 4544 u_int *npermp; 4545 4546 permission_set_get_array(ssh, who, where, &permp, &npermp); 4547 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4548 *npermp = 0; 4549 } 4550 4551 /* 4552 * Update the listen port for a dynamic remote forward, after 4553 * the actual 'newport' has been allocated. If 'newport' < 0 is 4554 * passed then they entry will be invalidated. 4555 */ 4556 void 4557 channel_update_permission(struct ssh *ssh, int idx, int newport) 4558 { 4559 struct permission_set *pset = &ssh->chanctxt->local_perms; 4560 4561 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4562 debug_f("index out of range: %d num_permitted_user %d", 4563 idx, pset->num_permitted_user); 4564 return; 4565 } 4566 debug("%s allowed port %d for forwarding to host %s port %d", 4567 newport > 0 ? "Updating" : "Removing", 4568 newport, 4569 pset->permitted_user[idx].host_to_connect, 4570 pset->permitted_user[idx].port_to_connect); 4571 if (newport <= 0) 4572 fwd_perm_clear(&pset->permitted_user[idx]); 4573 else { 4574 pset->permitted_user[idx].listen_port = 4575 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4576 } 4577 } 4578 4579 /* Try to start non-blocking connect to next host in cctx list */ 4580 static int 4581 connect_next(struct channel_connect *cctx) 4582 { 4583 int sock, saved_errno; 4584 struct sockaddr_un *sunaddr; 4585 char ntop[NI_MAXHOST]; 4586 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4587 4588 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4589 switch (cctx->ai->ai_family) { 4590 case AF_UNIX: 4591 /* unix:pathname instead of host:port */ 4592 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4593 strlcpy(ntop, "unix", sizeof(ntop)); 4594 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4595 break; 4596 case AF_INET: 4597 case AF_INET6: 4598 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4599 ntop, sizeof(ntop), strport, sizeof(strport), 4600 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4601 error_f("getnameinfo failed"); 4602 continue; 4603 } 4604 break; 4605 default: 4606 continue; 4607 } 4608 debug_f("start for host %.100s ([%.100s]:%s)", 4609 cctx->host, ntop, strport); 4610 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4611 cctx->ai->ai_protocol)) == -1) { 4612 if (cctx->ai->ai_next == NULL) 4613 error("socket: %.100s", strerror(errno)); 4614 else 4615 verbose("socket: %.100s", strerror(errno)); 4616 continue; 4617 } 4618 if (set_nonblock(sock) == -1) 4619 fatal_f("set_nonblock(%d)", sock); 4620 if (connect(sock, cctx->ai->ai_addr, 4621 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4622 debug_f("host %.100s ([%.100s]:%s): %.100s", 4623 cctx->host, ntop, strport, strerror(errno)); 4624 saved_errno = errno; 4625 close(sock); 4626 errno = saved_errno; 4627 continue; /* fail -- try next */ 4628 } 4629 if (cctx->ai->ai_family != AF_UNIX) 4630 set_nodelay(sock); 4631 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4632 cctx->host, ntop, strport, sock); 4633 cctx->ai = cctx->ai->ai_next; 4634 return sock; 4635 } 4636 return -1; 4637 } 4638 4639 static void 4640 channel_connect_ctx_free(struct channel_connect *cctx) 4641 { 4642 free(cctx->host); 4643 if (cctx->aitop) { 4644 if (cctx->aitop->ai_family == AF_UNIX) 4645 free(cctx->aitop); 4646 else 4647 freeaddrinfo(cctx->aitop); 4648 } 4649 memset(cctx, 0, sizeof(*cctx)); 4650 } 4651 4652 /* 4653 * Return connecting socket to remote host:port or local socket path, 4654 * passing back the failure reason if appropriate. 4655 */ 4656 static int 4657 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4658 char *ctype, char *rname, struct channel_connect *cctx, 4659 int *reason, const char **errmsg) 4660 { 4661 struct addrinfo hints; 4662 int gaierr; 4663 int sock = -1; 4664 char strport[NI_MAXSERV]; 4665 4666 if (port == PORT_STREAMLOCAL) { 4667 struct sockaddr_un *sunaddr; 4668 struct addrinfo *ai; 4669 4670 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4671 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4672 return -1; 4673 } 4674 4675 /* 4676 * Fake up a struct addrinfo for AF_UNIX connections. 4677 * channel_connect_ctx_free() must check ai_family 4678 * and use free() not freeaddirinfo() for AF_UNIX. 4679 */ 4680 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4681 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4682 ai->ai_addr = (struct sockaddr *)(ai + 1); 4683 ai->ai_addrlen = sizeof(*sunaddr); 4684 ai->ai_family = AF_UNIX; 4685 ai->ai_socktype = socktype; 4686 ai->ai_protocol = PF_UNSPEC; 4687 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4688 sunaddr->sun_family = AF_UNIX; 4689 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4690 cctx->aitop = ai; 4691 } else { 4692 memset(&hints, 0, sizeof(hints)); 4693 hints.ai_family = ssh->chanctxt->IPv4or6; 4694 hints.ai_socktype = socktype; 4695 snprintf(strport, sizeof strport, "%d", port); 4696 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4697 != 0) { 4698 if (errmsg != NULL) 4699 *errmsg = ssh_gai_strerror(gaierr); 4700 if (reason != NULL) 4701 *reason = SSH2_OPEN_CONNECT_FAILED; 4702 error("connect_to %.100s: unknown host (%s)", name, 4703 ssh_gai_strerror(gaierr)); 4704 return -1; 4705 } 4706 } 4707 4708 cctx->host = xstrdup(name); 4709 cctx->port = port; 4710 cctx->ai = cctx->aitop; 4711 4712 if ((sock = connect_next(cctx)) == -1) { 4713 error("connect to %.100s port %d failed: %s", 4714 name, port, strerror(errno)); 4715 return -1; 4716 } 4717 4718 return sock; 4719 } 4720 4721 /* Return CONNECTING channel to remote host:port or local socket path */ 4722 static Channel * 4723 connect_to(struct ssh *ssh, const char *host, int port, 4724 char *ctype, char *rname) 4725 { 4726 struct channel_connect cctx; 4727 Channel *c; 4728 int sock; 4729 4730 memset(&cctx, 0, sizeof(cctx)); 4731 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4732 &cctx, NULL, NULL); 4733 if (sock == -1) { 4734 channel_connect_ctx_free(&cctx); 4735 return NULL; 4736 } 4737 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4738 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4739 c->host_port = port; 4740 c->path = xstrdup(host); 4741 c->connect_ctx = cctx; 4742 4743 return c; 4744 } 4745 4746 /* 4747 * returns either the newly connected channel or the downstream channel 4748 * that needs to deal with this connection. 4749 */ 4750 Channel * 4751 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4752 u_short listen_port, char *ctype, char *rname) 4753 { 4754 struct ssh_channels *sc = ssh->chanctxt; 4755 struct permission_set *pset = &sc->local_perms; 4756 u_int i; 4757 struct permission *perm; 4758 4759 for (i = 0; i < pset->num_permitted_user; i++) { 4760 perm = &pset->permitted_user[i]; 4761 if (open_listen_match_tcpip(perm, 4762 listen_host, listen_port, 1)) { 4763 if (perm->downstream) 4764 return perm->downstream; 4765 if (perm->port_to_connect == 0) 4766 return rdynamic_connect_prepare(ssh, 4767 ctype, rname); 4768 return connect_to(ssh, 4769 perm->host_to_connect, perm->port_to_connect, 4770 ctype, rname); 4771 } 4772 } 4773 error("WARNING: Server requests forwarding for unknown listen_port %d", 4774 listen_port); 4775 return NULL; 4776 } 4777 4778 Channel * 4779 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4780 char *ctype, char *rname) 4781 { 4782 struct ssh_channels *sc = ssh->chanctxt; 4783 struct permission_set *pset = &sc->local_perms; 4784 u_int i; 4785 struct permission *perm; 4786 4787 for (i = 0; i < pset->num_permitted_user; i++) { 4788 perm = &pset->permitted_user[i]; 4789 if (open_listen_match_streamlocal(perm, path)) { 4790 return connect_to(ssh, 4791 perm->host_to_connect, perm->port_to_connect, 4792 ctype, rname); 4793 } 4794 } 4795 error("WARNING: Server requests forwarding for unknown path %.100s", 4796 path); 4797 return NULL; 4798 } 4799 4800 /* Check if connecting to that port is permitted and connect. */ 4801 Channel * 4802 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4803 char *ctype, char *rname, int *reason, const char **errmsg) 4804 { 4805 struct ssh_channels *sc = ssh->chanctxt; 4806 struct permission_set *pset = &sc->local_perms; 4807 struct channel_connect cctx; 4808 Channel *c; 4809 u_int i, permit, permit_adm = 1; 4810 int sock; 4811 struct permission *perm; 4812 4813 permit = pset->all_permitted; 4814 if (!permit) { 4815 for (i = 0; i < pset->num_permitted_user; i++) { 4816 perm = &pset->permitted_user[i]; 4817 if (open_match(perm, host, port)) { 4818 permit = 1; 4819 break; 4820 } 4821 } 4822 } 4823 4824 if (pset->num_permitted_admin > 0) { 4825 permit_adm = 0; 4826 for (i = 0; i < pset->num_permitted_admin; i++) { 4827 perm = &pset->permitted_admin[i]; 4828 if (open_match(perm, host, port)) { 4829 permit_adm = 1; 4830 break; 4831 } 4832 } 4833 } 4834 4835 if (!permit || !permit_adm) { 4836 logit("Received request from %.100s port %d to connect to " 4837 "host %.100s port %d, but the request was denied.", 4838 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4839 if (reason != NULL) 4840 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4841 return NULL; 4842 } 4843 4844 memset(&cctx, 0, sizeof(cctx)); 4845 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4846 &cctx, reason, errmsg); 4847 if (sock == -1) { 4848 channel_connect_ctx_free(&cctx); 4849 return NULL; 4850 } 4851 4852 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4853 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4854 c->host_port = port; 4855 c->path = xstrdup(host); 4856 c->connect_ctx = cctx; 4857 4858 return c; 4859 } 4860 4861 /* Check if connecting to that path is permitted and connect. */ 4862 Channel * 4863 channel_connect_to_path(struct ssh *ssh, const char *path, 4864 char *ctype, char *rname) 4865 { 4866 struct ssh_channels *sc = ssh->chanctxt; 4867 struct permission_set *pset = &sc->local_perms; 4868 u_int i, permit, permit_adm = 1; 4869 struct permission *perm; 4870 4871 permit = pset->all_permitted; 4872 if (!permit) { 4873 for (i = 0; i < pset->num_permitted_user; i++) { 4874 perm = &pset->permitted_user[i]; 4875 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4876 permit = 1; 4877 break; 4878 } 4879 } 4880 } 4881 4882 if (pset->num_permitted_admin > 0) { 4883 permit_adm = 0; 4884 for (i = 0; i < pset->num_permitted_admin; i++) { 4885 perm = &pset->permitted_admin[i]; 4886 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4887 permit_adm = 1; 4888 break; 4889 } 4890 } 4891 } 4892 4893 if (!permit || !permit_adm) { 4894 logit("Received request to connect to path %.100s, " 4895 "but the request was denied.", path); 4896 return NULL; 4897 } 4898 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4899 } 4900 4901 void 4902 channel_send_window_changes(struct ssh *ssh) 4903 { 4904 struct ssh_channels *sc = ssh->chanctxt; 4905 struct winsize ws; 4906 int r; 4907 u_int i; 4908 4909 for (i = 0; i < sc->channels_alloc; i++) { 4910 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4911 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4912 continue; 4913 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4914 continue; 4915 channel_request_start(ssh, i, "window-change", 0); 4916 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4917 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4918 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4919 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4920 (r = sshpkt_send(ssh)) != 0) 4921 fatal_fr(r, "channel %u; send window-change", i); 4922 } 4923 } 4924 4925 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4926 static Channel * 4927 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4928 { 4929 Channel *c; 4930 int r; 4931 4932 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4933 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4934 c->host_port = 0; 4935 c->path = NULL; 4936 4937 /* 4938 * We need to open the channel before we have a FD, 4939 * so that we can get SOCKS header from peer. 4940 */ 4941 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4942 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4943 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4944 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4945 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4946 fatal_fr(r, "channel %i; confirm", c->self); 4947 return c; 4948 } 4949 4950 /* Return CONNECTING socket to remote host:port or local socket path */ 4951 static int 4952 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4953 { 4954 struct ssh_channels *sc = ssh->chanctxt; 4955 struct permission_set *pset = &sc->local_perms; 4956 struct permission *perm; 4957 struct channel_connect cctx; 4958 u_int i, permit_adm = 1; 4959 int sock; 4960 4961 if (pset->num_permitted_admin > 0) { 4962 permit_adm = 0; 4963 for (i = 0; i < pset->num_permitted_admin; i++) { 4964 perm = &pset->permitted_admin[i]; 4965 if (open_match(perm, c->path, c->host_port)) { 4966 permit_adm = 1; 4967 break; 4968 } 4969 } 4970 } 4971 if (!permit_adm) { 4972 debug_f("requested forward not permitted"); 4973 return -1; 4974 } 4975 4976 memset(&cctx, 0, sizeof(cctx)); 4977 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4978 NULL, &cctx, NULL, NULL); 4979 if (sock == -1) 4980 channel_connect_ctx_free(&cctx); 4981 else { 4982 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4983 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4984 c->connect_ctx = cctx; 4985 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4986 } 4987 return sock; 4988 } 4989 4990 /* -- X11 forwarding */ 4991 4992 /* 4993 * Creates an internet domain socket for listening for X11 connections. 4994 * Returns 0 and a suitable display number for the DISPLAY variable 4995 * stored in display_numberp , or -1 if an error occurs. 4996 */ 4997 int 4998 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4999 int x11_use_localhost, int single_connection, 5000 u_int *display_numberp, int **chanids) 5001 { 5002 Channel *nc = NULL; 5003 int display_number, sock, port; 5004 struct addrinfo hints, *ai, *aitop; 5005 char strport[NI_MAXSERV]; 5006 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 5007 5008 if (chanids == NULL || x11_display_offset < 0 || 5009 x11_display_offset > UINT16_MAX - X11_BASE_PORT - MAX_DISPLAYS) 5010 return -1; 5011 5012 for (display_number = x11_display_offset; 5013 display_number < MAX_DISPLAYS; 5014 display_number++) { 5015 port = X11_BASE_PORT + display_number; 5016 memset(&hints, 0, sizeof(hints)); 5017 hints.ai_family = ssh->chanctxt->IPv4or6; 5018 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 5019 hints.ai_socktype = SOCK_STREAM; 5020 snprintf(strport, sizeof strport, "%d", port); 5021 if ((gaierr = getaddrinfo(NULL, strport, 5022 &hints, &aitop)) != 0) { 5023 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 5024 return -1; 5025 } 5026 for (ai = aitop; ai; ai = ai->ai_next) { 5027 if (ai->ai_family != AF_INET && 5028 ai->ai_family != AF_INET6) 5029 continue; 5030 sock = socket(ai->ai_family, ai->ai_socktype, 5031 ai->ai_protocol); 5032 if (sock == -1) { 5033 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 5034 #ifdef EPFNOSUPPORT 5035 && (errno != EPFNOSUPPORT) 5036 #endif 5037 ) { 5038 error("socket: %.100s", strerror(errno)); 5039 freeaddrinfo(aitop); 5040 return -1; 5041 } else { 5042 debug("x11_create_display_inet: Socket family %d not supported", 5043 ai->ai_family); 5044 continue; 5045 } 5046 } 5047 if (ai->ai_family == AF_INET6) 5048 sock_set_v6only(sock); 5049 if (x11_use_localhost) 5050 set_reuseaddr(sock); 5051 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5052 debug2_f("bind port %d: %.100s", port, 5053 strerror(errno)); 5054 close(sock); 5055 for (n = 0; n < num_socks; n++) 5056 close(socks[n]); 5057 num_socks = 0; 5058 break; 5059 } 5060 socks[num_socks++] = sock; 5061 if (num_socks == NUM_SOCKS) 5062 break; 5063 } 5064 freeaddrinfo(aitop); 5065 if (num_socks > 0) 5066 break; 5067 } 5068 if (display_number >= MAX_DISPLAYS) { 5069 error("Failed to allocate internet-domain X11 display socket."); 5070 return -1; 5071 } 5072 /* Start listening for connections on the socket. */ 5073 for (n = 0; n < num_socks; n++) { 5074 sock = socks[n]; 5075 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5076 error("listen: %.100s", strerror(errno)); 5077 close(sock); 5078 return -1; 5079 } 5080 } 5081 5082 /* Allocate a channel for each socket. */ 5083 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5084 for (n = 0; n < num_socks; n++) { 5085 sock = socks[n]; 5086 nc = channel_new(ssh, "x11-listener", 5087 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5088 CHAN_X11_WINDOW_DEFAULT, 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_path(const char *pathname) 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 return -1; 5110 } 5111 memset(&addr, 0, sizeof(addr)); 5112 addr.sun_family = AF_UNIX; 5113 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 5114 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5115 return sock; 5116 close(sock); 5117 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5118 return -1; 5119 } 5120 5121 static int 5122 connect_local_xsocket(u_int dnr) 5123 { 5124 char buf[1024]; 5125 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 5126 return connect_local_xsocket_path(buf); 5127 } 5128 5129 #ifdef __APPLE__ 5130 static int 5131 is_path_to_xsocket(const char *display, char *path, size_t pathlen) 5132 { 5133 struct stat sbuf; 5134 5135 if (strlcpy(path, display, pathlen) >= pathlen) { 5136 error("%s: display path too long", __func__); 5137 return 0; 5138 } 5139 if (display[0] != '/') 5140 return 0; 5141 if (stat(path, &sbuf) == 0) { 5142 return 1; 5143 } else { 5144 char *dot = strrchr(path, '.'); 5145 if (dot != NULL) { 5146 *dot = '\0'; 5147 if (stat(path, &sbuf) == 0) { 5148 return 1; 5149 } 5150 } 5151 } 5152 return 0; 5153 } 5154 #endif 5155 5156 int 5157 x11_connect_display(struct ssh *ssh) 5158 { 5159 u_int display_number; 5160 const char *display; 5161 char buf[1024], *cp; 5162 struct addrinfo hints, *ai, *aitop; 5163 char strport[NI_MAXSERV]; 5164 int gaierr, sock = 0; 5165 5166 /* Try to open a socket for the local X server. */ 5167 display = getenv("DISPLAY"); 5168 if (!display) { 5169 error("DISPLAY not set."); 5170 return -1; 5171 } 5172 /* 5173 * Now we decode the value of the DISPLAY variable and make a 5174 * connection to the real X server. 5175 */ 5176 5177 #ifdef __APPLE__ 5178 /* Check if display is a path to a socket (as set by launchd). */ 5179 { 5180 char path[PATH_MAX]; 5181 5182 if (is_path_to_xsocket(display, path, sizeof(path))) { 5183 debug("x11_connect_display: $DISPLAY is launchd"); 5184 5185 /* Create a socket. */ 5186 sock = connect_local_xsocket_path(path); 5187 if (sock < 0) 5188 return -1; 5189 5190 /* OK, we now have a connection to the display. */ 5191 return sock; 5192 } 5193 } 5194 #endif 5195 /* 5196 * Check if it is a unix domain socket. Unix domain displays are in 5197 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5198 */ 5199 if (strncmp(display, "unix:", 5) == 0 || 5200 display[0] == ':') { 5201 /* Connect to the unix domain socket. */ 5202 if (sscanf(strrchr(display, ':') + 1, "%u", 5203 &display_number) != 1) { 5204 error("Could not parse display number from DISPLAY: " 5205 "%.100s", display); 5206 return -1; 5207 } 5208 /* Create a socket. */ 5209 sock = connect_local_xsocket(display_number); 5210 if (sock < 0) 5211 return -1; 5212 5213 /* OK, we now have a connection to the display. */ 5214 return sock; 5215 } 5216 /* 5217 * Connect to an inet socket. The DISPLAY value is supposedly 5218 * hostname:d[.s], where hostname may also be numeric IP address. 5219 */ 5220 strlcpy(buf, display, sizeof(buf)); 5221 cp = strchr(buf, ':'); 5222 if (!cp) { 5223 error("Could not find ':' in DISPLAY: %.100s", display); 5224 return -1; 5225 } 5226 *cp = 0; 5227 /* 5228 * buf now contains the host name. But first we parse the 5229 * display number. 5230 */ 5231 if (sscanf(cp + 1, "%u", &display_number) != 1 || 5232 display_number > UINT16_MAX - X11_BASE_PORT) { 5233 error("Could not parse display number from DISPLAY: %.100s", 5234 display); 5235 return -1; 5236 } 5237 5238 /* Look up the host address */ 5239 memset(&hints, 0, sizeof(hints)); 5240 hints.ai_family = ssh->chanctxt->IPv4or6; 5241 hints.ai_socktype = SOCK_STREAM; 5242 snprintf(strport, sizeof strport, "%u", X11_BASE_PORT + display_number); 5243 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5244 error("%.100s: unknown host. (%s)", buf, 5245 ssh_gai_strerror(gaierr)); 5246 return -1; 5247 } 5248 for (ai = aitop; ai; ai = ai->ai_next) { 5249 /* Create a socket. */ 5250 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5251 if (sock == -1) { 5252 debug2("socket: %.100s", strerror(errno)); 5253 continue; 5254 } 5255 /* Connect it to the display. */ 5256 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5257 debug2("connect %.100s port %u: %.100s", buf, 5258 X11_BASE_PORT + display_number, strerror(errno)); 5259 close(sock); 5260 continue; 5261 } 5262 /* Success */ 5263 break; 5264 } 5265 freeaddrinfo(aitop); 5266 if (!ai) { 5267 error("connect %.100s port %u: %.100s", buf, 5268 X11_BASE_PORT + display_number, strerror(errno)); 5269 return -1; 5270 } 5271 set_nodelay(sock); 5272 return sock; 5273 } 5274 5275 /* 5276 * Requests forwarding of X11 connections, generates fake authentication 5277 * data, and enables authentication spoofing. 5278 * This should be called in the client only. 5279 */ 5280 void 5281 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5282 const char *disp, const char *proto, const char *data, int want_reply) 5283 { 5284 struct ssh_channels *sc = ssh->chanctxt; 5285 u_int data_len = (u_int) strlen(data) / 2; 5286 u_int i, value; 5287 const char *cp; 5288 char *new_data; 5289 int r, screen_number; 5290 5291 if (sc->x11_saved_display == NULL) 5292 sc->x11_saved_display = xstrdup(disp); 5293 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5294 error("x11_request_forwarding_with_spoofing: different " 5295 "$DISPLAY already forwarded"); 5296 return; 5297 } 5298 5299 cp = strchr(disp, ':'); 5300 if (cp) 5301 cp = strchr(cp, '.'); 5302 if (cp) 5303 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5304 else 5305 screen_number = 0; 5306 5307 if (sc->x11_saved_proto == NULL) { 5308 /* Save protocol name. */ 5309 sc->x11_saved_proto = xstrdup(proto); 5310 5311 /* Extract real authentication data. */ 5312 sc->x11_saved_data = xmalloc(data_len); 5313 for (i = 0; i < data_len; i++) { 5314 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5315 fatal("x11_request_forwarding: bad " 5316 "authentication data: %.100s", data); 5317 } 5318 sc->x11_saved_data[i] = value; 5319 } 5320 sc->x11_saved_data_len = data_len; 5321 5322 /* Generate fake data of the same length. */ 5323 sc->x11_fake_data = xmalloc(data_len); 5324 arc4random_buf(sc->x11_fake_data, data_len); 5325 sc->x11_fake_data_len = data_len; 5326 } 5327 5328 /* Convert the fake data into hex. */ 5329 new_data = tohex(sc->x11_fake_data, data_len); 5330 5331 /* Send the request packet. */ 5332 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5333 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5334 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5335 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5336 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5337 (r = sshpkt_send(ssh)) != 0 || 5338 (r = ssh_packet_write_wait(ssh)) != 0) 5339 fatal_fr(r, "send x11-req"); 5340 free(new_data); 5341 } 5342 5343 /* 5344 * Returns whether an x11 channel was used recently (less than a second ago) 5345 */ 5346 int 5347 x11_channel_used_recently(struct ssh *ssh) { 5348 u_int i; 5349 Channel *c; 5350 time_t lastused = 0; 5351 5352 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 5353 c = ssh->chanctxt->channels[i]; 5354 if (c == NULL || c->ctype == NULL || c->lastused == 0 || 5355 strcmp(c->ctype, "x11-connection") != 0) 5356 continue; 5357 lastused = c->lastused; 5358 } 5359 return lastused != 0 && monotime() > lastused + 1; 5360 } 5361