1 /* $OpenBSD: channels.c,v 1.437 2024/03/06 02:59:59 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include "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 /* -- tcp forwarding */ 97 /* special-case port number meaning allow any port */ 98 #define FWD_PERMIT_ANY_PORT 0 99 100 /* special-case wildcard meaning allow any host */ 101 #define FWD_PERMIT_ANY_HOST "*" 102 103 /* -- X11 forwarding */ 104 /* Maximum number of fake X11 displays to try. */ 105 #define MAX_DISPLAYS 1000 106 107 /* Per-channel callback for pre/post IO actions */ 108 typedef void chan_fn(struct ssh *, Channel *c); 109 110 /* 111 * Data structure for storing which hosts are permitted for forward requests. 112 * The local sides of any remote forwards are stored in this array to prevent 113 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 114 * network (which might be behind a firewall). 115 */ 116 /* XXX: streamlocal wants a path instead of host:port */ 117 /* Overload host_to_connect; we could just make this match Forward */ 118 /* XXX - can we use listen_host instead of listen_path? */ 119 struct permission { 120 char *host_to_connect; /* Connect to 'host'. */ 121 int port_to_connect; /* Connect to 'port'. */ 122 char *listen_host; /* Remote side should listen address. */ 123 char *listen_path; /* Remote side should listen path. */ 124 int listen_port; /* Remote side should listen port. */ 125 Channel *downstream; /* Downstream mux*/ 126 }; 127 128 /* 129 * Stores the forwarding permission state for a single direction (local or 130 * remote). 131 */ 132 struct permission_set { 133 /* 134 * List of all local permitted host/port pairs to allow for the 135 * user. 136 */ 137 u_int num_permitted_user; 138 struct permission *permitted_user; 139 140 /* 141 * List of all permitted host/port pairs to allow for the admin. 142 */ 143 u_int num_permitted_admin; 144 struct permission *permitted_admin; 145 146 /* 147 * If this is true, all opens/listens are permitted. This is the 148 * case on the server on which we have to trust the client anyway, 149 * and the user could do anything after logging in. 150 */ 151 int all_permitted; 152 }; 153 154 /* Used to record timeouts per channel type */ 155 struct ssh_channel_timeout { 156 char *type_pattern; 157 int timeout_secs; 158 }; 159 160 /* Master structure for channels state */ 161 struct ssh_channels { 162 /* 163 * Pointer to an array containing all allocated channels. The array 164 * is dynamically extended as needed. 165 */ 166 Channel **channels; 167 168 /* 169 * Size of the channel array. All slots of the array must always be 170 * initialized (at least the type field); unused slots set to NULL 171 */ 172 u_int channels_alloc; 173 174 /* 175 * 'channel_pre*' are called just before IO to add any bits 176 * relevant to channels in the c->io_want bitmasks. 177 * 178 * 'channel_post*': perform any appropriate operations for 179 * channels which have c->io_ready events pending. 180 */ 181 chan_fn **channel_pre; 182 chan_fn **channel_post; 183 184 /* -- tcp forwarding */ 185 struct permission_set local_perms; 186 struct permission_set remote_perms; 187 188 /* -- X11 forwarding */ 189 190 /* Saved X11 local (client) display. */ 191 char *x11_saved_display; 192 193 /* Saved X11 authentication protocol name. */ 194 char *x11_saved_proto; 195 196 /* Saved X11 authentication data. This is the real data. */ 197 char *x11_saved_data; 198 u_int x11_saved_data_len; 199 200 /* Deadline after which all X11 connections are refused */ 201 time_t x11_refuse_time; 202 203 /* 204 * Fake X11 authentication data. This is what the server will be 205 * sending us; we should replace any occurrences of this by the 206 * real data. 207 */ 208 u_char *x11_fake_data; 209 u_int x11_fake_data_len; 210 211 /* AF_UNSPEC or AF_INET or AF_INET6 */ 212 int IPv4or6; 213 214 /* Channel timeouts by type */ 215 struct ssh_channel_timeout *timeouts; 216 size_t ntimeouts; 217 /* Global timeout for all OPEN channels */ 218 int global_deadline; 219 time_t lastused; 220 }; 221 222 /* helper */ 223 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 224 static const char *channel_rfwd_bind_host(const char *listen_host); 225 226 /* non-blocking connect helpers */ 227 static int connect_next(struct channel_connect *); 228 static void channel_connect_ctx_free(struct channel_connect *); 229 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 230 static int rdynamic_connect_finish(struct ssh *, Channel *); 231 232 /* Setup helper */ 233 static void channel_handler_init(struct ssh_channels *sc); 234 235 /* -- channel core */ 236 237 void 238 channel_init_channels(struct ssh *ssh) 239 { 240 struct ssh_channels *sc; 241 242 if ((sc = calloc(1, sizeof(*sc))) == NULL) 243 fatal_f("allocation failed"); 244 sc->channels_alloc = 10; 245 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 246 sc->IPv4or6 = AF_UNSPEC; 247 channel_handler_init(sc); 248 249 ssh->chanctxt = sc; 250 } 251 252 Channel * 253 channel_by_id(struct ssh *ssh, int id) 254 { 255 Channel *c; 256 257 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 258 logit_f("%d: bad id", id); 259 return NULL; 260 } 261 c = ssh->chanctxt->channels[id]; 262 if (c == NULL) { 263 logit_f("%d: bad id: channel free", id); 264 return NULL; 265 } 266 return c; 267 } 268 269 Channel * 270 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 271 { 272 Channel *c; 273 u_int i; 274 275 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 276 c = ssh->chanctxt->channels[i]; 277 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 278 return c; 279 } 280 return NULL; 281 } 282 283 /* 284 * Returns the channel if it is allowed to receive protocol messages. 285 * Private channels, like listening sockets, may not receive messages. 286 */ 287 Channel * 288 channel_lookup(struct ssh *ssh, int id) 289 { 290 Channel *c; 291 292 if ((c = channel_by_id(ssh, id)) == NULL) 293 return NULL; 294 295 switch (c->type) { 296 case SSH_CHANNEL_X11_OPEN: 297 case SSH_CHANNEL_LARVAL: 298 case SSH_CHANNEL_CONNECTING: 299 case SSH_CHANNEL_DYNAMIC: 300 case SSH_CHANNEL_RDYNAMIC_OPEN: 301 case SSH_CHANNEL_RDYNAMIC_FINISH: 302 case SSH_CHANNEL_OPENING: 303 case SSH_CHANNEL_OPEN: 304 case SSH_CHANNEL_ABANDONED: 305 case SSH_CHANNEL_MUX_PROXY: 306 return c; 307 } 308 logit("Non-public channel %d, type %d.", id, c->type); 309 return NULL; 310 } 311 312 /* 313 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 314 * match type_pattern. 315 */ 316 void 317 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 318 int timeout_secs) 319 { 320 struct ssh_channels *sc = ssh->chanctxt; 321 322 if (strcmp(type_pattern, "global") == 0) { 323 debug2_f("global channel timeout %d seconds", timeout_secs); 324 sc->global_deadline = timeout_secs; 325 return; 326 } 327 debug2_f("channel type \"%s\" timeout %d seconds", 328 type_pattern, timeout_secs); 329 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 330 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 331 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 332 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 333 sc->ntimeouts++; 334 } 335 336 /* Clears all previously-added channel timeouts */ 337 void 338 channel_clear_timeouts(struct ssh *ssh) 339 { 340 struct ssh_channels *sc = ssh->chanctxt; 341 size_t i; 342 343 debug3_f("clearing"); 344 for (i = 0; i < sc->ntimeouts; i++) 345 free(sc->timeouts[i].type_pattern); 346 free(sc->timeouts); 347 sc->timeouts = NULL; 348 sc->ntimeouts = 0; 349 } 350 351 static int 352 lookup_timeout(struct ssh *ssh, const char *type) 353 { 354 struct ssh_channels *sc = ssh->chanctxt; 355 size_t i; 356 357 for (i = 0; i < sc->ntimeouts; i++) { 358 if (match_pattern(type, sc->timeouts[i].type_pattern)) 359 return sc->timeouts[i].timeout_secs; 360 } 361 362 return 0; 363 } 364 365 /* 366 * Sets "extended type" of a channel; used by session layer to add additional 367 * information about channel types (e.g. shell, login, subsystem) that can then 368 * be used to select timeouts. 369 * Will reset c->inactive_deadline as a side-effect. 370 */ 371 void 372 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 373 { 374 Channel *c; 375 376 if ((c = channel_by_id(ssh, id)) == NULL) 377 fatal_f("missing channel %d", id); 378 if (c->xctype != NULL) 379 free(c->xctype); 380 c->xctype = xstrdup(xctype); 381 /* Type has changed, so look up inactivity deadline again */ 382 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 383 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 384 c->inactive_deadline); 385 } 386 387 /* 388 * update "last used" time on a channel. 389 * NB. nothing else should update lastused except to clear it. 390 */ 391 static void 392 channel_set_used_time(struct ssh *ssh, Channel *c) 393 { 394 ssh->chanctxt->lastused = monotime(); 395 if (c != NULL) 396 c->lastused = ssh->chanctxt->lastused; 397 } 398 399 /* 400 * Get the time at which a channel is due to time out for inactivity. 401 * Returns 0 if the channel is not due to time out ever. 402 */ 403 static time_t 404 channel_get_expiry(struct ssh *ssh, Channel *c) 405 { 406 struct ssh_channels *sc = ssh->chanctxt; 407 time_t expiry = 0, channel_expiry; 408 409 if (sc->lastused != 0 && sc->global_deadline != 0) 410 expiry = sc->lastused + sc->global_deadline; 411 if (c->lastused != 0 && c->inactive_deadline != 0) { 412 channel_expiry = c->lastused + c->inactive_deadline; 413 if (expiry == 0 || channel_expiry < expiry) 414 expiry = channel_expiry; 415 } 416 return expiry; 417 } 418 419 /* 420 * Register filedescriptors for a channel, used when allocating a channel or 421 * when the channel consumer/producer is ready, e.g. shell exec'd 422 */ 423 static void 424 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 425 int extusage, int nonblock, int is_tty) 426 { 427 int val; 428 429 if (rfd != -1) 430 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 431 if (wfd != -1 && wfd != rfd) 432 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 433 if (efd != -1 && efd != rfd && efd != wfd) 434 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 435 436 c->rfd = rfd; 437 c->wfd = wfd; 438 c->sock = (rfd == wfd) ? rfd : -1; 439 c->efd = efd; 440 c->extended_usage = extusage; 441 442 if ((c->isatty = is_tty) != 0) 443 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 444 #ifdef _AIX 445 /* XXX: Later AIX versions can't push as much data to tty */ 446 c->wfd_isatty = is_tty || isatty(c->wfd); 447 #endif 448 449 /* enable nonblocking mode */ 450 c->restore_block = 0; 451 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 452 /* 453 * Special handling for stdio file descriptors: do not set 454 * non-blocking mode if they are TTYs. Otherwise prepare to 455 * restore their blocking state on exit to avoid interfering 456 * with other programs that follow. 457 */ 458 if (rfd != -1 && !isatty(rfd) && 459 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 460 c->restore_flags[0] = val; 461 c->restore_block |= CHANNEL_RESTORE_RFD; 462 set_nonblock(rfd); 463 } 464 if (wfd != -1 && !isatty(wfd) && 465 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 466 c->restore_flags[1] = val; 467 c->restore_block |= CHANNEL_RESTORE_WFD; 468 set_nonblock(wfd); 469 } 470 if (efd != -1 && !isatty(efd) && 471 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 472 c->restore_flags[2] = val; 473 c->restore_block |= CHANNEL_RESTORE_EFD; 474 set_nonblock(efd); 475 } 476 } else if (nonblock) { 477 if (rfd != -1) 478 set_nonblock(rfd); 479 if (wfd != -1) 480 set_nonblock(wfd); 481 if (efd != -1) 482 set_nonblock(efd); 483 } 484 /* channel might be entering a larval state, so reset global timeout */ 485 channel_set_used_time(ssh, NULL); 486 } 487 488 /* 489 * Allocate a new channel object and set its type and socket. 490 */ 491 Channel * 492 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 493 u_int window, u_int maxpack, int extusage, const char *remote_name, 494 int nonblock) 495 { 496 struct ssh_channels *sc = ssh->chanctxt; 497 u_int i, found = 0; 498 Channel *c; 499 int r; 500 501 /* Try to find a free slot where to put the new channel. */ 502 for (i = 0; i < sc->channels_alloc; i++) { 503 if (sc->channels[i] == NULL) { 504 /* Found a free slot. */ 505 found = i; 506 break; 507 } 508 } 509 if (i >= sc->channels_alloc) { 510 /* 511 * There are no free slots. Take last+1 slot and expand 512 * the array. 513 */ 514 found = sc->channels_alloc; 515 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 516 fatal_f("internal error: channels_alloc %d too big", 517 sc->channels_alloc); 518 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 519 sc->channels_alloc + 10, sizeof(*sc->channels)); 520 sc->channels_alloc += 10; 521 debug2("channel: expanding %d", sc->channels_alloc); 522 } 523 /* Initialize and return new channel. */ 524 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 525 if ((c->input = sshbuf_new()) == NULL || 526 (c->output = sshbuf_new()) == NULL || 527 (c->extended = sshbuf_new()) == NULL) 528 fatal_f("sshbuf_new failed"); 529 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 530 fatal_fr(r, "sshbuf_set_max_size"); 531 c->ostate = CHAN_OUTPUT_OPEN; 532 c->istate = CHAN_INPUT_OPEN; 533 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 534 c->self = found; 535 c->type = type; 536 c->ctype = ctype; 537 c->local_window = window; 538 c->local_window_max = window; 539 c->local_maxpacket = maxpack; 540 c->remote_name = xstrdup(remote_name); 541 c->ctl_chan = -1; 542 c->delayed = 1; /* prevent call to channel_post handler */ 543 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 544 TAILQ_INIT(&c->status_confirms); 545 debug("channel %d: new %s [%s] (inactive timeout: %u)", 546 found, c->ctype, remote_name, c->inactive_deadline); 547 return c; 548 } 549 550 int 551 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 552 { 553 int ret, fd = *fdp; 554 555 if (fd == -1) 556 return 0; 557 558 /* restore blocking */ 559 if (*fdp == c->rfd && 560 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 561 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 562 else if (*fdp == c->wfd && 563 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 564 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 565 else if (*fdp == c->efd && 566 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 567 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 568 569 if (*fdp == c->rfd) { 570 c->io_want &= ~SSH_CHAN_IO_RFD; 571 c->io_ready &= ~SSH_CHAN_IO_RFD; 572 c->rfd = -1; 573 c->pfds[0] = -1; 574 } 575 if (*fdp == c->wfd) { 576 c->io_want &= ~SSH_CHAN_IO_WFD; 577 c->io_ready &= ~SSH_CHAN_IO_WFD; 578 c->wfd = -1; 579 c->pfds[1] = -1; 580 } 581 if (*fdp == c->efd) { 582 c->io_want &= ~SSH_CHAN_IO_EFD; 583 c->io_ready &= ~SSH_CHAN_IO_EFD; 584 c->efd = -1; 585 c->pfds[2] = -1; 586 } 587 if (*fdp == c->sock) { 588 c->io_want &= ~SSH_CHAN_IO_SOCK; 589 c->io_ready &= ~SSH_CHAN_IO_SOCK; 590 c->sock = -1; 591 c->pfds[3] = -1; 592 } 593 594 ret = close(fd); 595 *fdp = -1; /* probably redundant */ 596 return ret; 597 } 598 599 /* Close all channel fd/socket. */ 600 static void 601 channel_close_fds(struct ssh *ssh, Channel *c) 602 { 603 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 604 605 channel_close_fd(ssh, c, &c->sock); 606 if (rfd != sock) 607 channel_close_fd(ssh, c, &c->rfd); 608 if (wfd != sock && wfd != rfd) 609 channel_close_fd(ssh, c, &c->wfd); 610 if (efd != sock && efd != rfd && efd != wfd) 611 channel_close_fd(ssh, c, &c->efd); 612 } 613 614 static void 615 fwd_perm_clear(struct permission *perm) 616 { 617 free(perm->host_to_connect); 618 free(perm->listen_host); 619 free(perm->listen_path); 620 memset(perm, 0, sizeof(*perm)); 621 } 622 623 /* Returns an printable name for the specified forwarding permission list */ 624 static const char * 625 fwd_ident(int who, int where) 626 { 627 if (who == FORWARD_ADM) { 628 if (where == FORWARD_LOCAL) 629 return "admin local"; 630 else if (where == FORWARD_REMOTE) 631 return "admin remote"; 632 } else if (who == FORWARD_USER) { 633 if (where == FORWARD_LOCAL) 634 return "user local"; 635 else if (where == FORWARD_REMOTE) 636 return "user remote"; 637 } 638 fatal("Unknown forward permission list %d/%d", who, where); 639 } 640 641 /* Returns the forwarding permission list for the specified direction */ 642 static struct permission_set * 643 permission_set_get(struct ssh *ssh, int where) 644 { 645 struct ssh_channels *sc = ssh->chanctxt; 646 647 switch (where) { 648 case FORWARD_LOCAL: 649 return &sc->local_perms; 650 break; 651 case FORWARD_REMOTE: 652 return &sc->remote_perms; 653 break; 654 default: 655 fatal_f("invalid forwarding direction %d", where); 656 } 657 } 658 659 /* Returns pointers to the specified forwarding list and its element count */ 660 static void 661 permission_set_get_array(struct ssh *ssh, int who, int where, 662 struct permission ***permpp, u_int **npermpp) 663 { 664 struct permission_set *pset = permission_set_get(ssh, where); 665 666 switch (who) { 667 case FORWARD_USER: 668 *permpp = &pset->permitted_user; 669 *npermpp = &pset->num_permitted_user; 670 break; 671 case FORWARD_ADM: 672 *permpp = &pset->permitted_admin; 673 *npermpp = &pset->num_permitted_admin; 674 break; 675 default: 676 fatal_f("invalid forwarding client %d", who); 677 } 678 } 679 680 /* Adds an entry to the specified forwarding list */ 681 static int 682 permission_set_add(struct ssh *ssh, int who, int where, 683 const char *host_to_connect, int port_to_connect, 684 const char *listen_host, const char *listen_path, int listen_port, 685 Channel *downstream) 686 { 687 struct permission **permp; 688 u_int n, *npermp; 689 690 permission_set_get_array(ssh, who, where, &permp, &npermp); 691 692 if (*npermp >= INT_MAX) 693 fatal_f("%s overflow", fwd_ident(who, where)); 694 695 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 696 n = (*npermp)++; 697 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 698 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 699 (*permp)[n].port_to_connect = port_to_connect; 700 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 701 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 702 (*permp)[n].listen_port = listen_port; 703 (*permp)[n].downstream = downstream; 704 #undef MAYBE_DUP 705 return (int)n; 706 } 707 708 static void 709 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 710 { 711 struct ssh_channels *sc = ssh->chanctxt; 712 struct permission_set *pset = &sc->local_perms; 713 struct permission *perm; 714 int r; 715 u_int i; 716 717 for (i = 0; i < pset->num_permitted_user; i++) { 718 perm = &pset->permitted_user[i]; 719 if (perm->downstream != c) 720 continue; 721 722 /* cancel on the server, since mux client is gone */ 723 debug("channel %d: cleanup remote forward for %s:%u", 724 c->self, perm->listen_host, perm->listen_port); 725 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 726 (r = sshpkt_put_cstring(ssh, 727 "cancel-tcpip-forward")) != 0 || 728 (r = sshpkt_put_u8(ssh, 0)) != 0 || 729 (r = sshpkt_put_cstring(ssh, 730 channel_rfwd_bind_host(perm->listen_host))) != 0 || 731 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 732 (r = sshpkt_send(ssh)) != 0) { 733 fatal_fr(r, "channel %i", c->self); 734 } 735 fwd_perm_clear(perm); /* unregister */ 736 } 737 } 738 739 /* Free the channel and close its fd/socket. */ 740 void 741 channel_free(struct ssh *ssh, Channel *c) 742 { 743 struct ssh_channels *sc = ssh->chanctxt; 744 char *s; 745 u_int i, n; 746 Channel *other; 747 struct channel_confirm *cc; 748 749 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 750 if ((other = sc->channels[i]) == NULL) 751 continue; 752 n++; 753 /* detach from mux client and prepare for closing */ 754 if (c->type == SSH_CHANNEL_MUX_CLIENT && 755 other->type == SSH_CHANNEL_MUX_PROXY && 756 other->mux_ctx == c) { 757 other->mux_ctx = NULL; 758 other->type = SSH_CHANNEL_OPEN; 759 other->istate = CHAN_INPUT_CLOSED; 760 other->ostate = CHAN_OUTPUT_CLOSED; 761 } 762 } 763 debug("channel %d: free: %s, nchannels %u", c->self, 764 c->remote_name ? c->remote_name : "???", n); 765 766 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 767 mux_remove_remote_forwardings(ssh, c); 768 free(c->mux_ctx); 769 c->mux_ctx = NULL; 770 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 771 free(c->mux_ctx); 772 c->mux_ctx = NULL; 773 } 774 775 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 776 s = channel_open_message(ssh); 777 debug3("channel %d: status: %s", c->self, s); 778 free(s); 779 } 780 781 channel_close_fds(ssh, c); 782 sshbuf_free(c->input); 783 sshbuf_free(c->output); 784 sshbuf_free(c->extended); 785 c->input = c->output = c->extended = NULL; 786 free(c->remote_name); 787 c->remote_name = NULL; 788 free(c->path); 789 c->path = NULL; 790 free(c->listening_addr); 791 c->listening_addr = NULL; 792 free(c->xctype); 793 c->xctype = NULL; 794 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 795 if (cc->abandon_cb != NULL) 796 cc->abandon_cb(ssh, c, cc->ctx); 797 TAILQ_REMOVE(&c->status_confirms, cc, entry); 798 freezero(cc, sizeof(*cc)); 799 } 800 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 801 c->filter_cleanup(ssh, c->self, c->filter_ctx); 802 sc->channels[c->self] = NULL; 803 freezero(c, sizeof(*c)); 804 } 805 806 void 807 channel_free_all(struct ssh *ssh) 808 { 809 u_int i; 810 struct ssh_channels *sc = ssh->chanctxt; 811 812 for (i = 0; i < sc->channels_alloc; i++) 813 if (sc->channels[i] != NULL) 814 channel_free(ssh, sc->channels[i]); 815 816 free(sc->channels); 817 sc->channels = NULL; 818 sc->channels_alloc = 0; 819 820 free(sc->x11_saved_display); 821 sc->x11_saved_display = NULL; 822 823 free(sc->x11_saved_proto); 824 sc->x11_saved_proto = NULL; 825 826 free(sc->x11_saved_data); 827 sc->x11_saved_data = NULL; 828 sc->x11_saved_data_len = 0; 829 830 free(sc->x11_fake_data); 831 sc->x11_fake_data = NULL; 832 sc->x11_fake_data_len = 0; 833 } 834 835 /* 836 * Closes the sockets/fds of all channels. This is used to close extra file 837 * descriptors after a fork. 838 */ 839 void 840 channel_close_all(struct ssh *ssh) 841 { 842 u_int i; 843 844 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 845 if (ssh->chanctxt->channels[i] != NULL) 846 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 847 } 848 849 /* 850 * Stop listening to channels. 851 */ 852 void 853 channel_stop_listening(struct ssh *ssh) 854 { 855 u_int i; 856 Channel *c; 857 858 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 859 c = ssh->chanctxt->channels[i]; 860 if (c != NULL) { 861 switch (c->type) { 862 case SSH_CHANNEL_AUTH_SOCKET: 863 case SSH_CHANNEL_PORT_LISTENER: 864 case SSH_CHANNEL_RPORT_LISTENER: 865 case SSH_CHANNEL_X11_LISTENER: 866 case SSH_CHANNEL_UNIX_LISTENER: 867 case SSH_CHANNEL_RUNIX_LISTENER: 868 channel_close_fd(ssh, c, &c->sock); 869 channel_free(ssh, c); 870 break; 871 } 872 } 873 } 874 } 875 876 /* 877 * Returns true if no channel has too much buffered data, and false if one or 878 * more channel is overfull. 879 */ 880 int 881 channel_not_very_much_buffered_data(struct ssh *ssh) 882 { 883 u_int i; 884 u_int maxsize = ssh_packet_get_maxsize(ssh); 885 Channel *c; 886 887 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 888 c = ssh->chanctxt->channels[i]; 889 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 890 continue; 891 if (sshbuf_len(c->output) > maxsize) { 892 debug2("channel %d: big output buffer %zu > %u", 893 c->self, sshbuf_len(c->output), maxsize); 894 return 0; 895 } 896 } 897 return 1; 898 } 899 900 /* Returns true if any channel is still open. */ 901 int 902 channel_still_open(struct ssh *ssh) 903 { 904 u_int i; 905 Channel *c; 906 907 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 908 c = ssh->chanctxt->channels[i]; 909 if (c == NULL) 910 continue; 911 switch (c->type) { 912 case SSH_CHANNEL_X11_LISTENER: 913 case SSH_CHANNEL_PORT_LISTENER: 914 case SSH_CHANNEL_RPORT_LISTENER: 915 case SSH_CHANNEL_MUX_LISTENER: 916 case SSH_CHANNEL_CLOSED: 917 case SSH_CHANNEL_AUTH_SOCKET: 918 case SSH_CHANNEL_DYNAMIC: 919 case SSH_CHANNEL_RDYNAMIC_OPEN: 920 case SSH_CHANNEL_CONNECTING: 921 case SSH_CHANNEL_ZOMBIE: 922 case SSH_CHANNEL_ABANDONED: 923 case SSH_CHANNEL_UNIX_LISTENER: 924 case SSH_CHANNEL_RUNIX_LISTENER: 925 continue; 926 case SSH_CHANNEL_LARVAL: 927 continue; 928 case SSH_CHANNEL_OPENING: 929 case SSH_CHANNEL_OPEN: 930 case SSH_CHANNEL_RDYNAMIC_FINISH: 931 case SSH_CHANNEL_X11_OPEN: 932 case SSH_CHANNEL_MUX_CLIENT: 933 case SSH_CHANNEL_MUX_PROXY: 934 return 1; 935 default: 936 fatal_f("bad channel type %d", c->type); 937 /* NOTREACHED */ 938 } 939 } 940 return 0; 941 } 942 943 /* Returns true if a channel with a TTY is open. */ 944 int 945 channel_tty_open(struct ssh *ssh) 946 { 947 u_int i; 948 Channel *c; 949 950 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 951 c = ssh->chanctxt->channels[i]; 952 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 953 continue; 954 if (c->client_tty) 955 return 1; 956 } 957 return 0; 958 } 959 960 /* Returns the id of an open channel suitable for keepaliving */ 961 int 962 channel_find_open(struct ssh *ssh) 963 { 964 u_int i; 965 Channel *c; 966 967 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 968 c = ssh->chanctxt->channels[i]; 969 if (c == NULL || !c->have_remote_id) 970 continue; 971 switch (c->type) { 972 case SSH_CHANNEL_CLOSED: 973 case SSH_CHANNEL_DYNAMIC: 974 case SSH_CHANNEL_RDYNAMIC_OPEN: 975 case SSH_CHANNEL_RDYNAMIC_FINISH: 976 case SSH_CHANNEL_X11_LISTENER: 977 case SSH_CHANNEL_PORT_LISTENER: 978 case SSH_CHANNEL_RPORT_LISTENER: 979 case SSH_CHANNEL_MUX_LISTENER: 980 case SSH_CHANNEL_MUX_CLIENT: 981 case SSH_CHANNEL_MUX_PROXY: 982 case SSH_CHANNEL_OPENING: 983 case SSH_CHANNEL_CONNECTING: 984 case SSH_CHANNEL_ZOMBIE: 985 case SSH_CHANNEL_ABANDONED: 986 case SSH_CHANNEL_UNIX_LISTENER: 987 case SSH_CHANNEL_RUNIX_LISTENER: 988 continue; 989 case SSH_CHANNEL_LARVAL: 990 case SSH_CHANNEL_AUTH_SOCKET: 991 case SSH_CHANNEL_OPEN: 992 case SSH_CHANNEL_X11_OPEN: 993 return i; 994 default: 995 fatal_f("bad channel type %d", c->type); 996 /* NOTREACHED */ 997 } 998 } 999 return -1; 1000 } 1001 1002 /* Returns the state of the channel's extended usage flag */ 1003 const char * 1004 channel_format_extended_usage(const Channel *c) 1005 { 1006 if (c->efd == -1) 1007 return "closed"; 1008 1009 switch (c->extended_usage) { 1010 case CHAN_EXTENDED_WRITE: 1011 return "write"; 1012 case CHAN_EXTENDED_READ: 1013 return "read"; 1014 case CHAN_EXTENDED_IGNORE: 1015 return "ignore"; 1016 default: 1017 return "UNKNOWN"; 1018 } 1019 } 1020 1021 static char * 1022 channel_format_status(const Channel *c) 1023 { 1024 char *ret = NULL; 1025 1026 xasprintf(&ret, "t%d [%s] %s%u i%u/%zu o%u/%zu e[%s]/%zu " 1027 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 1028 c->type, c->xctype != NULL ? c->xctype : c->ctype, 1029 c->have_remote_id ? "r" : "nr", c->remote_id, 1030 c->istate, sshbuf_len(c->input), 1031 c->ostate, sshbuf_len(c->output), 1032 channel_format_extended_usage(c), sshbuf_len(c->extended), 1033 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 1034 c->io_want, c->io_ready); 1035 return ret; 1036 } 1037 1038 /* 1039 * Returns a message describing the currently open forwarded connections, 1040 * suitable for sending to the client. The message contains crlf pairs for 1041 * newlines. 1042 */ 1043 char * 1044 channel_open_message(struct ssh *ssh) 1045 { 1046 struct sshbuf *buf; 1047 Channel *c; 1048 u_int i; 1049 int r; 1050 char *cp, *ret; 1051 1052 if ((buf = sshbuf_new()) == NULL) 1053 fatal_f("sshbuf_new"); 1054 if ((r = sshbuf_putf(buf, 1055 "The following connections are open:\r\n")) != 0) 1056 fatal_fr(r, "sshbuf_putf"); 1057 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1058 c = ssh->chanctxt->channels[i]; 1059 if (c == NULL) 1060 continue; 1061 switch (c->type) { 1062 case SSH_CHANNEL_X11_LISTENER: 1063 case SSH_CHANNEL_PORT_LISTENER: 1064 case SSH_CHANNEL_RPORT_LISTENER: 1065 case SSH_CHANNEL_CLOSED: 1066 case SSH_CHANNEL_AUTH_SOCKET: 1067 case SSH_CHANNEL_ZOMBIE: 1068 case SSH_CHANNEL_ABANDONED: 1069 case SSH_CHANNEL_MUX_LISTENER: 1070 case SSH_CHANNEL_UNIX_LISTENER: 1071 case SSH_CHANNEL_RUNIX_LISTENER: 1072 continue; 1073 case SSH_CHANNEL_LARVAL: 1074 case SSH_CHANNEL_OPENING: 1075 case SSH_CHANNEL_CONNECTING: 1076 case SSH_CHANNEL_DYNAMIC: 1077 case SSH_CHANNEL_RDYNAMIC_OPEN: 1078 case SSH_CHANNEL_RDYNAMIC_FINISH: 1079 case SSH_CHANNEL_OPEN: 1080 case SSH_CHANNEL_X11_OPEN: 1081 case SSH_CHANNEL_MUX_PROXY: 1082 case SSH_CHANNEL_MUX_CLIENT: 1083 cp = channel_format_status(c); 1084 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1085 c->self, c->remote_name, cp)) != 0) { 1086 free(cp); 1087 fatal_fr(r, "sshbuf_putf"); 1088 } 1089 free(cp); 1090 continue; 1091 default: 1092 fatal_f("bad channel type %d", c->type); 1093 /* NOTREACHED */ 1094 } 1095 } 1096 if ((ret = sshbuf_dup_string(buf)) == NULL) 1097 fatal_f("sshbuf_dup_string"); 1098 sshbuf_free(buf); 1099 return ret; 1100 } 1101 1102 static void 1103 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1104 { 1105 int r; 1106 1107 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1108 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1109 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1110 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1111 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1112 fatal_r(r, "%s: channel %i: open", where, c->self); 1113 } 1114 } 1115 1116 void 1117 channel_send_open(struct ssh *ssh, int id) 1118 { 1119 Channel *c = channel_lookup(ssh, id); 1120 int r; 1121 1122 if (c == NULL) { 1123 logit("channel_send_open: %d: bad id", id); 1124 return; 1125 } 1126 debug2("channel %d: send open", id); 1127 open_preamble(ssh, __func__, c, c->ctype); 1128 if ((r = sshpkt_send(ssh)) != 0) 1129 fatal_fr(r, "channel %i", c->self); 1130 } 1131 1132 void 1133 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 1134 { 1135 Channel *c = channel_lookup(ssh, id); 1136 int r; 1137 1138 if (c == NULL) { 1139 logit_f("%d: unknown channel id", id); 1140 return; 1141 } 1142 if (!c->have_remote_id) 1143 fatal_f("channel %d: no remote id", c->self); 1144 1145 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1146 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1147 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1148 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1149 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1150 fatal_fr(r, "channel %i", c->self); 1151 } 1152 } 1153 1154 void 1155 channel_register_status_confirm(struct ssh *ssh, int id, 1156 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1157 { 1158 struct channel_confirm *cc; 1159 Channel *c; 1160 1161 if ((c = channel_lookup(ssh, id)) == NULL) 1162 fatal_f("%d: bad id", id); 1163 1164 cc = xcalloc(1, sizeof(*cc)); 1165 cc->cb = cb; 1166 cc->abandon_cb = abandon_cb; 1167 cc->ctx = ctx; 1168 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1169 } 1170 1171 void 1172 channel_register_open_confirm(struct ssh *ssh, int id, 1173 channel_open_fn *fn, void *ctx) 1174 { 1175 Channel *c = channel_lookup(ssh, id); 1176 1177 if (c == NULL) { 1178 logit_f("%d: bad id", id); 1179 return; 1180 } 1181 c->open_confirm = fn; 1182 c->open_confirm_ctx = ctx; 1183 } 1184 1185 void 1186 channel_register_cleanup(struct ssh *ssh, int id, 1187 channel_callback_fn *fn, int do_close) 1188 { 1189 Channel *c = channel_by_id(ssh, id); 1190 1191 if (c == NULL) { 1192 logit_f("%d: bad id", id); 1193 return; 1194 } 1195 c->detach_user = fn; 1196 c->detach_close = do_close; 1197 } 1198 1199 void 1200 channel_cancel_cleanup(struct ssh *ssh, int id) 1201 { 1202 Channel *c = channel_by_id(ssh, id); 1203 1204 if (c == NULL) { 1205 logit_f("%d: bad id", id); 1206 return; 1207 } 1208 c->detach_user = NULL; 1209 c->detach_close = 0; 1210 } 1211 1212 void 1213 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1214 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1215 { 1216 Channel *c = channel_lookup(ssh, id); 1217 1218 if (c == NULL) { 1219 logit_f("%d: bad id", id); 1220 return; 1221 } 1222 c->input_filter = ifn; 1223 c->output_filter = ofn; 1224 c->filter_ctx = ctx; 1225 c->filter_cleanup = cfn; 1226 } 1227 1228 void 1229 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1230 int extusage, int nonblock, int is_tty, u_int window_max) 1231 { 1232 Channel *c = channel_lookup(ssh, id); 1233 int r; 1234 1235 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1236 fatal("channel_activate for non-larval channel %d.", id); 1237 if (!c->have_remote_id) 1238 fatal_f("channel %d: no remote id", c->self); 1239 1240 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1241 c->type = SSH_CHANNEL_OPEN; 1242 channel_set_used_time(ssh, c); 1243 c->local_window = c->local_window_max = window_max; 1244 1245 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1246 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1247 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1248 (r = sshpkt_send(ssh)) != 0) 1249 fatal_fr(r, "channel %i", c->self); 1250 } 1251 1252 static void 1253 channel_pre_listener(struct ssh *ssh, Channel *c) 1254 { 1255 c->io_want = SSH_CHAN_IO_SOCK_R; 1256 } 1257 1258 static void 1259 channel_pre_connecting(struct ssh *ssh, Channel *c) 1260 { 1261 debug3("channel %d: waiting for connection", c->self); 1262 c->io_want = SSH_CHAN_IO_SOCK_W; 1263 } 1264 1265 static void 1266 channel_pre_open(struct ssh *ssh, Channel *c) 1267 { 1268 c->io_want = 0; 1269 if (c->istate == CHAN_INPUT_OPEN && 1270 c->remote_window > 0 && 1271 sshbuf_len(c->input) < c->remote_window && 1272 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1273 c->io_want |= SSH_CHAN_IO_RFD; 1274 if (c->ostate == CHAN_OUTPUT_OPEN || 1275 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1276 if (sshbuf_len(c->output) > 0) { 1277 c->io_want |= SSH_CHAN_IO_WFD; 1278 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1279 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1280 debug2("channel %d: " 1281 "obuf_empty delayed efd %d/(%zu)", c->self, 1282 c->efd, sshbuf_len(c->extended)); 1283 else 1284 chan_obuf_empty(ssh, c); 1285 } 1286 } 1287 /** XXX check close conditions, too */ 1288 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1289 c->ostate == CHAN_OUTPUT_CLOSED)) { 1290 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1291 sshbuf_len(c->extended) > 0) 1292 c->io_want |= SSH_CHAN_IO_EFD_W; 1293 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1294 (c->extended_usage == CHAN_EXTENDED_READ || 1295 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1296 sshbuf_len(c->extended) < c->remote_window) 1297 c->io_want |= SSH_CHAN_IO_EFD_R; 1298 } 1299 /* XXX: What about efd? races? */ 1300 } 1301 1302 /* 1303 * This is a special state for X11 authentication spoofing. An opened X11 1304 * connection (when authentication spoofing is being done) remains in this 1305 * state until the first packet has been completely read. The authentication 1306 * data in that packet is then substituted by the real data if it matches the 1307 * fake data, and the channel is put into normal mode. 1308 * XXX All this happens at the client side. 1309 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1310 */ 1311 static int 1312 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1313 { 1314 struct ssh_channels *sc = ssh->chanctxt; 1315 u_char *ucp; 1316 u_int proto_len, data_len; 1317 1318 /* Is this being called after the refusal deadline? */ 1319 if (sc->x11_refuse_time != 0 && 1320 monotime() >= sc->x11_refuse_time) { 1321 verbose("Rejected X11 connection after ForwardX11Timeout " 1322 "expired"); 1323 return -1; 1324 } 1325 1326 /* Check if the fixed size part of the packet is in buffer. */ 1327 if (sshbuf_len(b) < 12) 1328 return 0; 1329 1330 /* Parse the lengths of variable-length fields. */ 1331 ucp = sshbuf_mutable_ptr(b); 1332 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1333 proto_len = 256 * ucp[6] + ucp[7]; 1334 data_len = 256 * ucp[8] + ucp[9]; 1335 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1336 proto_len = ucp[6] + 256 * ucp[7]; 1337 data_len = ucp[8] + 256 * ucp[9]; 1338 } else { 1339 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1340 ucp[0]); 1341 return -1; 1342 } 1343 1344 /* Check if the whole packet is in buffer. */ 1345 if (sshbuf_len(b) < 1346 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1347 return 0; 1348 1349 /* Check if authentication protocol matches. */ 1350 if (proto_len != strlen(sc->x11_saved_proto) || 1351 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1352 debug2("X11 connection uses different authentication protocol."); 1353 return -1; 1354 } 1355 /* Check if authentication data matches our fake data. */ 1356 if (data_len != sc->x11_fake_data_len || 1357 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1358 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1359 debug2("X11 auth data does not match fake data."); 1360 return -1; 1361 } 1362 /* Check fake data length */ 1363 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1364 error("X11 fake_data_len %d != saved_data_len %d", 1365 sc->x11_fake_data_len, sc->x11_saved_data_len); 1366 return -1; 1367 } 1368 /* 1369 * Received authentication protocol and data match 1370 * our fake data. Substitute the fake data with real 1371 * data. 1372 */ 1373 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1374 sc->x11_saved_data, sc->x11_saved_data_len); 1375 return 1; 1376 } 1377 1378 void 1379 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1380 { 1381 debug3_f("channel %d: forcibly closing", c->self); 1382 if (c->istate == CHAN_INPUT_OPEN) 1383 chan_read_failed(ssh, c); 1384 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1385 sshbuf_reset(c->input); 1386 chan_ibuf_empty(ssh, c); 1387 } 1388 if (c->ostate == CHAN_OUTPUT_OPEN || 1389 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1390 sshbuf_reset(c->output); 1391 chan_write_failed(ssh, c); 1392 } 1393 if (c->detach_user) 1394 c->detach_user(ssh, c->self, 1, NULL); 1395 if (c->efd != -1) 1396 channel_close_fd(ssh, c, &c->efd); 1397 if (abandon) 1398 c->type = SSH_CHANNEL_ABANDONED; 1399 /* exempt from inactivity timeouts */ 1400 c->inactive_deadline = 0; 1401 c->lastused = 0; 1402 } 1403 1404 static void 1405 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1406 { 1407 int ret = x11_open_helper(ssh, c->output); 1408 1409 /* c->force_drain = 1; */ 1410 1411 if (ret == 1) { 1412 c->type = SSH_CHANNEL_OPEN; 1413 channel_set_used_time(ssh, c); 1414 channel_pre_open(ssh, c); 1415 } else if (ret == -1) { 1416 logit("X11 connection rejected because of wrong " 1417 "authentication."); 1418 debug2("X11 rejected %d i%d/o%d", 1419 c->self, c->istate, c->ostate); 1420 channel_force_close(ssh, c, 0); 1421 } 1422 } 1423 1424 static void 1425 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1426 { 1427 c->io_want = 0; 1428 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1429 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1430 c->io_want |= SSH_CHAN_IO_RFD; 1431 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1432 /* clear buffer immediately (discard any partial packet) */ 1433 sshbuf_reset(c->input); 1434 chan_ibuf_empty(ssh, c); 1435 /* Start output drain. XXX just kill chan? */ 1436 chan_rcvd_oclose(ssh, c); 1437 } 1438 if (c->ostate == CHAN_OUTPUT_OPEN || 1439 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1440 if (sshbuf_len(c->output) > 0) 1441 c->io_want |= SSH_CHAN_IO_WFD; 1442 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1443 chan_obuf_empty(ssh, c); 1444 } 1445 } 1446 1447 /* try to decode a socks4 header */ 1448 static int 1449 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1450 { 1451 const u_char *p; 1452 char *host; 1453 u_int len, have, i, found, need; 1454 char username[256]; 1455 struct { 1456 u_int8_t version; 1457 u_int8_t command; 1458 u_int16_t dest_port; 1459 struct in_addr dest_addr; 1460 } s4_req, s4_rsp; 1461 int r; 1462 1463 debug2("channel %d: decode socks4", c->self); 1464 1465 have = sshbuf_len(input); 1466 len = sizeof(s4_req); 1467 if (have < len) 1468 return 0; 1469 p = sshbuf_ptr(input); 1470 1471 need = 1; 1472 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1473 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1474 debug2("channel %d: socks4a request", c->self); 1475 /* ... and needs an extra string (the hostname) */ 1476 need = 2; 1477 } 1478 /* Check for terminating NUL on the string(s) */ 1479 for (found = 0, i = len; i < have; i++) { 1480 if (p[i] == '\0') { 1481 found++; 1482 if (found == need) 1483 break; 1484 } 1485 if (i > 1024) { 1486 /* the peer is probably sending garbage */ 1487 debug("channel %d: decode socks4: too long", 1488 c->self); 1489 return -1; 1490 } 1491 } 1492 if (found < need) 1493 return 0; 1494 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1495 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1496 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1497 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1498 debug_r(r, "channels %d: decode socks4", c->self); 1499 return -1; 1500 } 1501 have = sshbuf_len(input); 1502 p = sshbuf_ptr(input); 1503 if (memchr(p, '\0', have) == NULL) { 1504 error("channel %d: decode socks4: unterminated user", c->self); 1505 return -1; 1506 } 1507 len = strlen(p); 1508 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1509 len++; /* trailing '\0' */ 1510 strlcpy(username, p, sizeof(username)); 1511 if ((r = sshbuf_consume(input, len)) != 0) 1512 fatal_fr(r, "channel %d: consume", c->self); 1513 free(c->path); 1514 c->path = NULL; 1515 if (need == 1) { /* SOCKS4: one string */ 1516 host = inet_ntoa(s4_req.dest_addr); 1517 c->path = xstrdup(host); 1518 } else { /* SOCKS4A: two strings */ 1519 have = sshbuf_len(input); 1520 p = sshbuf_ptr(input); 1521 if (memchr(p, '\0', have) == NULL) { 1522 error("channel %d: decode socks4a: host not nul " 1523 "terminated", c->self); 1524 return -1; 1525 } 1526 len = strlen(p); 1527 debug2("channel %d: decode socks4a: host %s/%d", 1528 c->self, p, len); 1529 len++; /* trailing '\0' */ 1530 if (len > NI_MAXHOST) { 1531 error("channel %d: hostname \"%.100s\" too long", 1532 c->self, p); 1533 return -1; 1534 } 1535 c->path = xstrdup(p); 1536 if ((r = sshbuf_consume(input, len)) != 0) 1537 fatal_fr(r, "channel %d: consume", c->self); 1538 } 1539 c->host_port = ntohs(s4_req.dest_port); 1540 1541 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1542 c->self, c->path, c->host_port, s4_req.command); 1543 1544 if (s4_req.command != 1) { 1545 debug("channel %d: cannot handle: %s cn %d", 1546 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1547 return -1; 1548 } 1549 s4_rsp.version = 0; /* vn: 0 for reply */ 1550 s4_rsp.command = 90; /* cd: req granted */ 1551 s4_rsp.dest_port = 0; /* ignored */ 1552 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1553 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1554 fatal_fr(r, "channel %d: append reply", c->self); 1555 return 1; 1556 } 1557 1558 /* try to decode a socks5 header */ 1559 #define SSH_SOCKS5_AUTHDONE 0x1000 1560 #define SSH_SOCKS5_NOAUTH 0x00 1561 #define SSH_SOCKS5_IPV4 0x01 1562 #define SSH_SOCKS5_DOMAIN 0x03 1563 #define SSH_SOCKS5_IPV6 0x04 1564 #define SSH_SOCKS5_CONNECT 0x01 1565 #define SSH_SOCKS5_SUCCESS 0x00 1566 1567 static int 1568 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1569 { 1570 /* XXX use get/put_u8 instead of trusting struct padding */ 1571 struct { 1572 u_int8_t version; 1573 u_int8_t command; 1574 u_int8_t reserved; 1575 u_int8_t atyp; 1576 } s5_req, s5_rsp; 1577 u_int16_t dest_port; 1578 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1579 const u_char *p; 1580 u_int have, need, i, found, nmethods, addrlen, af; 1581 int r; 1582 1583 debug2("channel %d: decode socks5", c->self); 1584 p = sshbuf_ptr(input); 1585 if (p[0] != 0x05) 1586 return -1; 1587 have = sshbuf_len(input); 1588 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1589 /* format: ver | nmethods | methods */ 1590 if (have < 2) 1591 return 0; 1592 nmethods = p[1]; 1593 if (have < nmethods + 2) 1594 return 0; 1595 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1596 for (found = 0, i = 2; i < nmethods + 2; i++) { 1597 if (p[i] == SSH_SOCKS5_NOAUTH) { 1598 found = 1; 1599 break; 1600 } 1601 } 1602 if (!found) { 1603 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1604 c->self); 1605 return -1; 1606 } 1607 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1608 fatal_fr(r, "channel %d: consume", c->self); 1609 /* version, method */ 1610 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1611 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1612 fatal_fr(r, "channel %d: append reply", c->self); 1613 c->flags |= SSH_SOCKS5_AUTHDONE; 1614 debug2("channel %d: socks5 auth done", c->self); 1615 return 0; /* need more */ 1616 } 1617 debug2("channel %d: socks5 post auth", c->self); 1618 if (have < sizeof(s5_req)+1) 1619 return 0; /* need more */ 1620 memcpy(&s5_req, p, sizeof(s5_req)); 1621 if (s5_req.version != 0x05 || 1622 s5_req.command != SSH_SOCKS5_CONNECT || 1623 s5_req.reserved != 0x00) { 1624 debug2("channel %d: only socks5 connect supported", c->self); 1625 return -1; 1626 } 1627 switch (s5_req.atyp){ 1628 case SSH_SOCKS5_IPV4: 1629 addrlen = 4; 1630 af = AF_INET; 1631 break; 1632 case SSH_SOCKS5_DOMAIN: 1633 addrlen = p[sizeof(s5_req)]; 1634 af = -1; 1635 break; 1636 case SSH_SOCKS5_IPV6: 1637 addrlen = 16; 1638 af = AF_INET6; 1639 break; 1640 default: 1641 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1642 return -1; 1643 } 1644 need = sizeof(s5_req) + addrlen + 2; 1645 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1646 need++; 1647 if (have < need) 1648 return 0; 1649 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1650 fatal_fr(r, "channel %d: consume", c->self); 1651 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1652 /* host string length */ 1653 if ((r = sshbuf_consume(input, 1)) != 0) 1654 fatal_fr(r, "channel %d: consume", c->self); 1655 } 1656 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1657 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1658 debug_r(r, "channel %d: parse addr/port", c->self); 1659 return -1; 1660 } 1661 dest_addr[addrlen] = '\0'; 1662 free(c->path); 1663 c->path = NULL; 1664 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1665 if (addrlen >= NI_MAXHOST) { 1666 error("channel %d: dynamic request: socks5 hostname " 1667 "\"%.100s\" too long", c->self, dest_addr); 1668 return -1; 1669 } 1670 c->path = xstrdup(dest_addr); 1671 } else { 1672 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1673 return -1; 1674 c->path = xstrdup(ntop); 1675 } 1676 c->host_port = ntohs(dest_port); 1677 1678 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1679 c->self, c->path, c->host_port, s5_req.command); 1680 1681 s5_rsp.version = 0x05; 1682 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1683 s5_rsp.reserved = 0; /* ignored */ 1684 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1685 dest_port = 0; /* ignored */ 1686 1687 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1688 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1689 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1690 fatal_fr(r, "channel %d: append reply", c->self); 1691 return 1; 1692 } 1693 1694 Channel * 1695 channel_connect_stdio_fwd(struct ssh *ssh, 1696 const char *host_to_connect, int port_to_connect, 1697 int in, int out, int nonblock) 1698 { 1699 Channel *c; 1700 1701 debug_f("%s:%d", host_to_connect, port_to_connect); 1702 1703 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1704 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1705 0, "stdio-forward", nonblock); 1706 1707 c->path = xstrdup(host_to_connect); 1708 c->host_port = port_to_connect; 1709 c->listening_port = 0; 1710 c->force_drain = 1; 1711 1712 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1713 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1714 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1715 1716 return c; 1717 } 1718 1719 /* dynamic port forwarding */ 1720 static void 1721 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1722 { 1723 const u_char *p; 1724 u_int have; 1725 int ret; 1726 1727 c->io_want = 0; 1728 have = sshbuf_len(c->input); 1729 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1730 /* sshbuf_dump(c->input, stderr); */ 1731 /* check if the fixed size part of the packet is in buffer. */ 1732 if (have < 3) { 1733 /* need more */ 1734 c->io_want |= SSH_CHAN_IO_RFD; 1735 return; 1736 } 1737 /* try to guess the protocol */ 1738 p = sshbuf_ptr(c->input); 1739 /* XXX sshbuf_peek_u8? */ 1740 switch (p[0]) { 1741 case 0x04: 1742 ret = channel_decode_socks4(c, c->input, c->output); 1743 break; 1744 case 0x05: 1745 ret = channel_decode_socks5(c, c->input, c->output); 1746 break; 1747 default: 1748 ret = -1; 1749 break; 1750 } 1751 if (ret < 0) { 1752 chan_mark_dead(ssh, c); 1753 } else if (ret == 0) { 1754 debug2("channel %d: pre_dynamic: need more", c->self); 1755 /* need more */ 1756 c->io_want |= SSH_CHAN_IO_RFD; 1757 if (sshbuf_len(c->output)) 1758 c->io_want |= SSH_CHAN_IO_WFD; 1759 } else { 1760 /* switch to the next state */ 1761 c->type = SSH_CHANNEL_OPENING; 1762 port_open_helper(ssh, c, "direct-tcpip"); 1763 } 1764 } 1765 1766 /* simulate read-error */ 1767 static void 1768 rdynamic_close(struct ssh *ssh, Channel *c) 1769 { 1770 c->type = SSH_CHANNEL_OPEN; 1771 channel_force_close(ssh, c, 0); 1772 } 1773 1774 /* reverse dynamic port forwarding */ 1775 static void 1776 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1777 { 1778 const u_char *p; 1779 u_int have, len; 1780 int r, ret; 1781 1782 have = sshbuf_len(c->output); 1783 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1784 /* sshbuf_dump(c->output, stderr); */ 1785 /* EOF received */ 1786 if (c->flags & CHAN_EOF_RCVD) { 1787 if ((r = sshbuf_consume(c->output, have)) != 0) 1788 fatal_fr(r, "channel %d: consume", c->self); 1789 rdynamic_close(ssh, c); 1790 return; 1791 } 1792 /* check if the fixed size part of the packet is in buffer. */ 1793 if (have < 3) 1794 return; 1795 /* try to guess the protocol */ 1796 p = sshbuf_ptr(c->output); 1797 switch (p[0]) { 1798 case 0x04: 1799 /* switch input/output for reverse forwarding */ 1800 ret = channel_decode_socks4(c, c->output, c->input); 1801 break; 1802 case 0x05: 1803 ret = channel_decode_socks5(c, c->output, c->input); 1804 break; 1805 default: 1806 ret = -1; 1807 break; 1808 } 1809 if (ret < 0) { 1810 rdynamic_close(ssh, c); 1811 } else if (ret == 0) { 1812 debug2("channel %d: pre_rdynamic: need more", c->self); 1813 /* send socks request to peer */ 1814 len = sshbuf_len(c->input); 1815 if (len > 0 && len < c->remote_window) { 1816 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1817 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1818 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1819 (r = sshpkt_send(ssh)) != 0) { 1820 fatal_fr(r, "channel %i: rdynamic", c->self); 1821 } 1822 if ((r = sshbuf_consume(c->input, len)) != 0) 1823 fatal_fr(r, "channel %d: consume", c->self); 1824 c->remote_window -= len; 1825 } 1826 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1827 /* the connect failed */ 1828 rdynamic_close(ssh, c); 1829 } 1830 } 1831 1832 /* This is our fake X11 server socket. */ 1833 static void 1834 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1835 { 1836 Channel *nc; 1837 struct sockaddr_storage addr; 1838 int r, newsock, oerrno, remote_port; 1839 socklen_t addrlen; 1840 char buf[16384], *remote_ipaddr; 1841 1842 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1843 return; 1844 1845 debug("X11 connection requested."); 1846 addrlen = sizeof(addr); 1847 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1848 if (c->single_connection) { 1849 oerrno = errno; 1850 debug2("single_connection: closing X11 listener."); 1851 channel_close_fd(ssh, c, &c->sock); 1852 chan_mark_dead(ssh, c); 1853 errno = oerrno; 1854 } 1855 if (newsock == -1) { 1856 if (errno != EINTR && errno != EWOULDBLOCK && 1857 errno != ECONNABORTED) 1858 error("accept: %.100s", strerror(errno)); 1859 if (errno == EMFILE || errno == ENFILE) 1860 c->notbefore = monotime() + 1; 1861 return; 1862 } 1863 set_nodelay(newsock); 1864 remote_ipaddr = get_peer_ipaddr(newsock); 1865 remote_port = get_peer_port(newsock); 1866 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1867 remote_ipaddr, remote_port); 1868 1869 nc = channel_new(ssh, "x11-connection", 1870 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1871 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1872 open_preamble(ssh, __func__, nc, "x11"); 1873 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1874 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1875 fatal_fr(r, "channel %i: reply", c->self); 1876 } 1877 if ((r = sshpkt_send(ssh)) != 0) 1878 fatal_fr(r, "channel %i: send", c->self); 1879 free(remote_ipaddr); 1880 } 1881 1882 static void 1883 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1884 { 1885 char *local_ipaddr = get_local_ipaddr(c->sock); 1886 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1887 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1888 int remote_port = get_peer_port(c->sock); 1889 int r; 1890 1891 if (remote_port == -1) { 1892 /* Fake addr/port to appease peers that validate it (Tectia) */ 1893 free(remote_ipaddr); 1894 remote_ipaddr = xstrdup("127.0.0.1"); 1895 remote_port = 65535; 1896 } 1897 1898 free(c->remote_name); 1899 xasprintf(&c->remote_name, 1900 "%s: listening port %d for %.100s port %d, " 1901 "connect from %.200s port %d to %.100s port %d", 1902 rtype, c->listening_port, c->path, c->host_port, 1903 remote_ipaddr, remote_port, local_ipaddr, local_port); 1904 1905 open_preamble(ssh, __func__, c, rtype); 1906 if (strcmp(rtype, "direct-tcpip") == 0) { 1907 /* target host, port */ 1908 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1909 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1910 fatal_fr(r, "channel %i: reply", c->self); 1911 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1912 /* target path */ 1913 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1914 fatal_fr(r, "channel %i: reply", c->self); 1915 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1916 /* listen path */ 1917 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1918 fatal_fr(r, "channel %i: reply", c->self); 1919 } else { 1920 /* listen address, port */ 1921 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1922 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1923 fatal_fr(r, "channel %i: reply", c->self); 1924 } 1925 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1926 /* reserved for future owner/mode info */ 1927 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1928 fatal_fr(r, "channel %i: reply", c->self); 1929 } else { 1930 /* originator host and port */ 1931 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1932 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1933 fatal_fr(r, "channel %i: reply", c->self); 1934 } 1935 if ((r = sshpkt_send(ssh)) != 0) 1936 fatal_fr(r, "channel %i: send", c->self); 1937 free(remote_ipaddr); 1938 free(local_ipaddr); 1939 } 1940 1941 void 1942 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1943 { 1944 ssh->chanctxt->x11_refuse_time = refuse_time; 1945 } 1946 1947 /* 1948 * This socket is listening for connections to a forwarded TCP/IP port. 1949 */ 1950 static void 1951 channel_post_port_listener(struct ssh *ssh, Channel *c) 1952 { 1953 Channel *nc; 1954 struct sockaddr_storage addr; 1955 int newsock, nextstate; 1956 socklen_t addrlen; 1957 char *rtype; 1958 1959 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1960 return; 1961 1962 debug("Connection to port %d forwarding to %.100s port %d requested.", 1963 c->listening_port, c->path, c->host_port); 1964 1965 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1966 nextstate = SSH_CHANNEL_OPENING; 1967 rtype = "forwarded-tcpip"; 1968 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1969 nextstate = SSH_CHANNEL_OPENING; 1970 rtype = "forwarded-streamlocal@openssh.com"; 1971 } else if (c->host_port == PORT_STREAMLOCAL) { 1972 nextstate = SSH_CHANNEL_OPENING; 1973 rtype = "direct-streamlocal@openssh.com"; 1974 } else if (c->host_port == 0) { 1975 nextstate = SSH_CHANNEL_DYNAMIC; 1976 rtype = "dynamic-tcpip"; 1977 } else { 1978 nextstate = SSH_CHANNEL_OPENING; 1979 rtype = "direct-tcpip"; 1980 } 1981 1982 addrlen = sizeof(addr); 1983 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1984 if (newsock == -1) { 1985 if (errno != EINTR && errno != EWOULDBLOCK && 1986 errno != ECONNABORTED) 1987 error("accept: %.100s", strerror(errno)); 1988 if (errno == EMFILE || errno == ENFILE) 1989 c->notbefore = monotime() + 1; 1990 return; 1991 } 1992 if (c->host_port != PORT_STREAMLOCAL) 1993 set_nodelay(newsock); 1994 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1995 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1996 nc->listening_port = c->listening_port; 1997 nc->host_port = c->host_port; 1998 if (c->path != NULL) 1999 nc->path = xstrdup(c->path); 2000 2001 if (nextstate != SSH_CHANNEL_DYNAMIC) 2002 port_open_helper(ssh, nc, rtype); 2003 } 2004 2005 /* 2006 * This is the authentication agent socket listening for connections from 2007 * clients. 2008 */ 2009 static void 2010 channel_post_auth_listener(struct ssh *ssh, Channel *c) 2011 { 2012 Channel *nc; 2013 int r, newsock; 2014 struct sockaddr_storage addr; 2015 socklen_t addrlen; 2016 2017 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2018 return; 2019 2020 addrlen = sizeof(addr); 2021 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2022 if (newsock == -1) { 2023 error("accept from auth socket: %.100s", strerror(errno)); 2024 if (errno == EMFILE || errno == ENFILE) 2025 c->notbefore = monotime() + 1; 2026 return; 2027 } 2028 nc = channel_new(ssh, "agent-connection", 2029 SSH_CHANNEL_OPENING, newsock, newsock, -1, 2030 c->local_window_max, c->local_maxpacket, 2031 0, "accepted auth socket", 1); 2032 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 2033 if ((r = sshpkt_send(ssh)) != 0) 2034 fatal_fr(r, "channel %i", c->self); 2035 } 2036 2037 static void 2038 channel_post_connecting(struct ssh *ssh, Channel *c) 2039 { 2040 int err = 0, sock, isopen, r; 2041 socklen_t sz = sizeof(err); 2042 2043 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2044 return; 2045 if (!c->have_remote_id) 2046 fatal_f("channel %d: no remote id", c->self); 2047 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2048 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2049 2050 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2051 err = errno; 2052 error("getsockopt SO_ERROR failed"); 2053 } 2054 2055 if (err == 0) { 2056 /* Non-blocking connection completed */ 2057 debug("channel %d: connected to %s port %d", 2058 c->self, c->connect_ctx.host, c->connect_ctx.port); 2059 channel_connect_ctx_free(&c->connect_ctx); 2060 c->type = SSH_CHANNEL_OPEN; 2061 channel_set_used_time(ssh, c); 2062 if (isopen) { 2063 /* no message necessary */ 2064 } else { 2065 if ((r = sshpkt_start(ssh, 2066 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2067 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2068 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2069 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2070 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2071 (r = sshpkt_send(ssh)) != 0) 2072 fatal_fr(r, "channel %i open confirm", c->self); 2073 } 2074 return; 2075 } 2076 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2077 return; 2078 2079 /* Non-blocking connection failed */ 2080 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2081 2082 /* Try next address, if any */ 2083 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2084 /* Exhausted all addresses for this destination */ 2085 error("connect_to %.100s port %d: failed.", 2086 c->connect_ctx.host, c->connect_ctx.port); 2087 channel_connect_ctx_free(&c->connect_ctx); 2088 if (isopen) { 2089 rdynamic_close(ssh, c); 2090 } else { 2091 if ((r = sshpkt_start(ssh, 2092 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2093 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2094 (r = sshpkt_put_u32(ssh, 2095 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2096 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2097 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2098 (r = sshpkt_send(ssh)) != 0) 2099 fatal_fr(r, "channel %i: failure", c->self); 2100 chan_mark_dead(ssh, c); 2101 } 2102 } 2103 2104 /* New non-blocking connection in progress */ 2105 close(c->sock); 2106 c->sock = c->rfd = c->wfd = sock; 2107 } 2108 2109 static int 2110 channel_handle_rfd(struct ssh *ssh, Channel *c) 2111 { 2112 char buf[CHAN_RBUF]; 2113 ssize_t len; 2114 int r, force; 2115 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2116 int pty_zeroread = 0; 2117 2118 #ifdef PTY_ZEROREAD 2119 /* Bug on AIX: read(1) can return 0 for a non-closed fd */ 2120 pty_zeroread = c->isatty; 2121 #endif 2122 2123 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2124 2125 if (!force && (c->io_ready & SSH_CHAN_IO_RFD) == 0) 2126 return 1; 2127 if ((avail = sshbuf_avail(c->input)) == 0) 2128 return 1; /* Shouldn't happen */ 2129 2130 /* 2131 * For "simple" channels (i.e. not datagram or filtered), we can 2132 * read directly to the channel buffer. 2133 */ 2134 if (!pty_zeroread && c->input_filter == NULL && !c->datagram) { 2135 /* Only OPEN channels have valid rwin */ 2136 if (c->type == SSH_CHANNEL_OPEN) { 2137 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2138 return 1; /* shouldn't happen */ 2139 if (maxlen > c->remote_window - have) 2140 maxlen = c->remote_window - have; 2141 } 2142 if (maxlen > avail) 2143 maxlen = avail; 2144 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2145 if (errno == EINTR || (!force && 2146 (errno == EAGAIN || errno == EWOULDBLOCK))) 2147 return 1; 2148 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2149 c->self, c->rfd, maxlen, ssh_err(r)); 2150 goto rfail; 2151 } 2152 if (nr != 0) 2153 channel_set_used_time(ssh, c); 2154 return 1; 2155 } 2156 2157 errno = 0; 2158 len = read(c->rfd, buf, sizeof(buf)); 2159 /* fixup AIX zero-length read with errno set to look more like errors */ 2160 if (pty_zeroread && len == 0 && errno != 0) 2161 len = -1; 2162 if (len == -1 && (errno == EINTR || 2163 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 2164 return 1; 2165 if (len < 0 || (!pty_zeroread && len == 0)) { 2166 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2167 c->self, c->rfd, len, 2168 len == 0 ? "closed" : strerror(errno)); 2169 rfail: 2170 if (c->type != SSH_CHANNEL_OPEN) { 2171 debug2("channel %d: not open", c->self); 2172 chan_mark_dead(ssh, c); 2173 return -1; 2174 } else { 2175 chan_read_failed(ssh, c); 2176 } 2177 return -1; 2178 } 2179 channel_set_used_time(ssh, c); 2180 if (c->input_filter != NULL) { 2181 if (c->input_filter(ssh, c, buf, len) == -1) { 2182 debug2("channel %d: filter stops", c->self); 2183 chan_read_failed(ssh, c); 2184 } 2185 } else if (c->datagram) { 2186 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2187 fatal_fr(r, "channel %i: put datagram", c->self); 2188 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2189 fatal_fr(r, "channel %i: put data", c->self); 2190 2191 return 1; 2192 } 2193 2194 static int 2195 channel_handle_wfd(struct ssh *ssh, Channel *c) 2196 { 2197 struct termios tio; 2198 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2199 size_t dlen, olen = 0; 2200 int r, len; 2201 2202 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2203 return 1; 2204 if (sshbuf_len(c->output) == 0) 2205 return 1; 2206 2207 /* Send buffered output data to the socket. */ 2208 olen = sshbuf_len(c->output); 2209 if (c->output_filter != NULL) { 2210 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2211 debug2("channel %d: filter stops", c->self); 2212 if (c->type != SSH_CHANNEL_OPEN) 2213 chan_mark_dead(ssh, c); 2214 else 2215 chan_write_failed(ssh, c); 2216 return -1; 2217 } 2218 } else if (c->datagram) { 2219 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2220 fatal_fr(r, "channel %i: get datagram", c->self); 2221 buf = data; 2222 } else { 2223 buf = data = sshbuf_mutable_ptr(c->output); 2224 dlen = sshbuf_len(c->output); 2225 } 2226 2227 if (c->datagram) { 2228 /* ignore truncated writes, datagrams might get lost */ 2229 len = write(c->wfd, buf, dlen); 2230 free(data); 2231 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2232 errno == EWOULDBLOCK)) 2233 return 1; 2234 if (len <= 0) 2235 goto write_fail; 2236 goto out; 2237 } 2238 2239 #ifdef _AIX 2240 /* XXX: Later AIX versions can't push as much data to tty */ 2241 if (c->wfd_isatty) 2242 dlen = MINIMUM(dlen, 8*1024); 2243 #endif 2244 2245 len = write(c->wfd, buf, dlen); 2246 if (len == -1 && 2247 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 2248 return 1; 2249 if (len <= 0) { 2250 write_fail: 2251 if (c->type != SSH_CHANNEL_OPEN) { 2252 debug2("channel %d: not open", c->self); 2253 chan_mark_dead(ssh, c); 2254 return -1; 2255 } else { 2256 chan_write_failed(ssh, c); 2257 } 2258 return -1; 2259 } 2260 channel_set_used_time(ssh, c); 2261 #ifndef BROKEN_TCGETATTR_ICANON 2262 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2263 if (tcgetattr(c->wfd, &tio) == 0 && 2264 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2265 /* 2266 * Simulate echo to reduce the impact of 2267 * traffic analysis. We need to match the 2268 * size of a SSH2_MSG_CHANNEL_DATA message 2269 * (4 byte channel id + buf) 2270 */ 2271 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2272 (r = sshpkt_send(ssh)) != 0) 2273 fatal_fr(r, "channel %i: ignore", c->self); 2274 } 2275 } 2276 #endif /* BROKEN_TCGETATTR_ICANON */ 2277 if ((r = sshbuf_consume(c->output, len)) != 0) 2278 fatal_fr(r, "channel %i: consume", c->self); 2279 out: 2280 c->local_consumed += olen - sshbuf_len(c->output); 2281 2282 return 1; 2283 } 2284 2285 static int 2286 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2287 { 2288 int r; 2289 ssize_t len; 2290 2291 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2292 return 1; 2293 if (sshbuf_len(c->extended) == 0) 2294 return 1; 2295 2296 len = write(c->efd, sshbuf_ptr(c->extended), 2297 sshbuf_len(c->extended)); 2298 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2299 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2300 errno == EWOULDBLOCK)) 2301 return 1; 2302 if (len <= 0) { 2303 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2304 channel_close_fd(ssh, c, &c->efd); 2305 } else { 2306 if ((r = sshbuf_consume(c->extended, len)) != 0) 2307 fatal_fr(r, "channel %i: consume", c->self); 2308 c->local_consumed += len; 2309 channel_set_used_time(ssh, c); 2310 } 2311 return 1; 2312 } 2313 2314 static int 2315 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2316 { 2317 char buf[CHAN_RBUF]; 2318 ssize_t len; 2319 int r, force; 2320 2321 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2322 2323 if (!force && (c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2324 return 1; 2325 2326 len = read(c->efd, buf, sizeof(buf)); 2327 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2328 if (len == -1 && (errno == EINTR || ((errno == EAGAIN || 2329 errno == EWOULDBLOCK) && !force))) 2330 return 1; 2331 if (len <= 0) { 2332 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2333 channel_close_fd(ssh, c, &c->efd); 2334 return 1; 2335 } 2336 channel_set_used_time(ssh, c); 2337 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2338 debug3("channel %d: discard efd", c->self); 2339 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2340 fatal_fr(r, "channel %i: append", c->self); 2341 return 1; 2342 } 2343 2344 static int 2345 channel_handle_efd(struct ssh *ssh, Channel *c) 2346 { 2347 if (c->efd == -1) 2348 return 1; 2349 2350 /** XXX handle drain efd, too */ 2351 2352 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2353 return channel_handle_efd_write(ssh, c); 2354 else if (c->extended_usage == CHAN_EXTENDED_READ || 2355 c->extended_usage == CHAN_EXTENDED_IGNORE) 2356 return channel_handle_efd_read(ssh, c); 2357 2358 return 1; 2359 } 2360 2361 static int 2362 channel_check_window(struct ssh *ssh, Channel *c) 2363 { 2364 int r; 2365 2366 if (c->type == SSH_CHANNEL_OPEN && 2367 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2368 ((c->local_window_max - c->local_window > 2369 c->local_maxpacket*3) || 2370 c->local_window < c->local_window_max/2) && 2371 c->local_consumed > 0) { 2372 if (!c->have_remote_id) 2373 fatal_f("channel %d: no remote id", c->self); 2374 if ((r = sshpkt_start(ssh, 2375 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2376 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2377 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2378 (r = sshpkt_send(ssh)) != 0) { 2379 fatal_fr(r, "channel %i", c->self); 2380 } 2381 debug2("channel %d: window %d sent adjust %d", c->self, 2382 c->local_window, c->local_consumed); 2383 c->local_window += c->local_consumed; 2384 c->local_consumed = 0; 2385 } 2386 return 1; 2387 } 2388 2389 static void 2390 channel_post_open(struct ssh *ssh, Channel *c) 2391 { 2392 channel_handle_rfd(ssh, c); 2393 channel_handle_wfd(ssh, c); 2394 channel_handle_efd(ssh, c); 2395 channel_check_window(ssh, c); 2396 } 2397 2398 static u_int 2399 read_mux(struct ssh *ssh, Channel *c, u_int need) 2400 { 2401 char buf[CHAN_RBUF]; 2402 ssize_t len; 2403 u_int rlen; 2404 int r; 2405 2406 if (sshbuf_len(c->input) < need) { 2407 rlen = need - sshbuf_len(c->input); 2408 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2409 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2410 return sshbuf_len(c->input); 2411 if (len <= 0) { 2412 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2413 c->self, c->rfd, len); 2414 chan_read_failed(ssh, c); 2415 return 0; 2416 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2417 fatal_fr(r, "channel %i: append", c->self); 2418 } 2419 return sshbuf_len(c->input); 2420 } 2421 2422 static void 2423 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2424 { 2425 u_int need; 2426 2427 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2428 return; 2429 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2430 return; 2431 if (c->mux_pause) 2432 return; 2433 2434 /* 2435 * Don't not read past the precise end of packets to 2436 * avoid disrupting fd passing. 2437 */ 2438 if (read_mux(ssh, c, 4) < 4) /* read header */ 2439 return; 2440 /* XXX sshbuf_peek_u32 */ 2441 need = PEEK_U32(sshbuf_ptr(c->input)); 2442 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2443 if (need > CHANNEL_MUX_MAX_PACKET) { 2444 debug2("channel %d: packet too big %u > %u", 2445 c->self, CHANNEL_MUX_MAX_PACKET, need); 2446 chan_rcvd_oclose(ssh, c); 2447 return; 2448 } 2449 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2450 return; 2451 if (c->mux_rcb(ssh, c) != 0) { 2452 debug("channel %d: mux_rcb failed", c->self); 2453 chan_mark_dead(ssh, c); 2454 return; 2455 } 2456 } 2457 2458 static void 2459 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2460 { 2461 ssize_t len; 2462 int r; 2463 2464 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2465 return; 2466 if (sshbuf_len(c->output) == 0) 2467 return; 2468 2469 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2470 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2471 return; 2472 if (len <= 0) { 2473 chan_mark_dead(ssh, c); 2474 return; 2475 } 2476 if ((r = sshbuf_consume(c->output, len)) != 0) 2477 fatal_fr(r, "channel %i: consume", c->self); 2478 } 2479 2480 static void 2481 channel_post_mux_client(struct ssh *ssh, Channel *c) 2482 { 2483 channel_post_mux_client_read(ssh, c); 2484 channel_post_mux_client_write(ssh, c); 2485 } 2486 2487 static void 2488 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2489 { 2490 Channel *nc; 2491 struct sockaddr_storage addr; 2492 socklen_t addrlen; 2493 int newsock; 2494 uid_t euid; 2495 gid_t egid; 2496 2497 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2498 return; 2499 2500 debug("multiplexing control connection"); 2501 2502 /* 2503 * Accept connection on control socket 2504 */ 2505 memset(&addr, 0, sizeof(addr)); 2506 addrlen = sizeof(addr); 2507 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2508 &addrlen)) == -1) { 2509 error_f("accept: %s", strerror(errno)); 2510 if (errno == EMFILE || errno == ENFILE) 2511 c->notbefore = monotime() + 1; 2512 return; 2513 } 2514 2515 if (getpeereid(newsock, &euid, &egid) == -1) { 2516 error_f("getpeereid failed: %s", strerror(errno)); 2517 close(newsock); 2518 return; 2519 } 2520 if ((euid != 0) && (getuid() != euid)) { 2521 error("multiplex uid mismatch: peer euid %u != uid %u", 2522 (u_int)euid, (u_int)getuid()); 2523 close(newsock); 2524 return; 2525 } 2526 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2527 newsock, newsock, -1, c->local_window_max, 2528 c->local_maxpacket, 0, "mux-control", 1); 2529 nc->mux_rcb = c->mux_rcb; 2530 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2531 /* establish state */ 2532 nc->mux_rcb(ssh, nc); 2533 /* mux state transitions must not elicit protocol messages */ 2534 nc->flags |= CHAN_LOCAL; 2535 } 2536 2537 static void 2538 channel_handler_init(struct ssh_channels *sc) 2539 { 2540 chan_fn **pre, **post; 2541 2542 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2543 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2544 fatal_f("allocation failed"); 2545 2546 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2547 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2548 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2549 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2550 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2551 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2552 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2553 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2554 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2555 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2556 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2557 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2558 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2559 2560 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2561 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2562 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2563 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2564 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2565 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2566 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2567 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2568 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2569 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2570 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2571 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2572 2573 sc->channel_pre = pre; 2574 sc->channel_post = post; 2575 } 2576 2577 /* gc dead channels */ 2578 static void 2579 channel_garbage_collect(struct ssh *ssh, Channel *c) 2580 { 2581 if (c == NULL) 2582 return; 2583 if (c->detach_user != NULL) { 2584 if (!chan_is_dead(ssh, c, c->detach_close)) 2585 return; 2586 2587 debug2("channel %d: gc: notify user", c->self); 2588 c->detach_user(ssh, c->self, 0, NULL); 2589 /* if we still have a callback */ 2590 if (c->detach_user != NULL) 2591 return; 2592 debug2("channel %d: gc: user detached", c->self); 2593 } 2594 if (!chan_is_dead(ssh, c, 1)) 2595 return; 2596 debug2("channel %d: garbage collecting", c->self); 2597 channel_free(ssh, c); 2598 } 2599 2600 enum channel_table { CHAN_PRE, CHAN_POST }; 2601 2602 static void 2603 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2604 { 2605 struct ssh_channels *sc = ssh->chanctxt; 2606 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2607 u_int i, oalloc; 2608 Channel *c; 2609 time_t now; 2610 2611 now = monotime(); 2612 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2613 c = sc->channels[i]; 2614 if (c == NULL) 2615 continue; 2616 /* Try to keep IO going while rekeying */ 2617 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2618 continue; 2619 if (c->delayed) { 2620 if (table == CHAN_PRE) 2621 c->delayed = 0; 2622 else 2623 continue; 2624 } 2625 if (ftab[c->type] != NULL) { 2626 if (table == CHAN_PRE && c->type == SSH_CHANNEL_OPEN && 2627 channel_get_expiry(ssh, c) != 0 && 2628 now >= channel_get_expiry(ssh, c)) { 2629 /* channel closed for inactivity */ 2630 verbose("channel %d: closing after %u seconds " 2631 "of inactivity", c->self, 2632 c->inactive_deadline); 2633 channel_force_close(ssh, c, 1); 2634 } else if (c->notbefore <= now) { 2635 /* Run handlers that are not paused. */ 2636 (*ftab[c->type])(ssh, c); 2637 /* inactivity timeouts must interrupt poll() */ 2638 if (timeout != NULL && 2639 c->type == SSH_CHANNEL_OPEN && 2640 channel_get_expiry(ssh, c) != 0) { 2641 ptimeout_deadline_monotime(timeout, 2642 channel_get_expiry(ssh, c)); 2643 } 2644 } else if (timeout != NULL) { 2645 /* 2646 * Arrange for poll() wakeup when channel pause 2647 * timer expires. 2648 */ 2649 ptimeout_deadline_monotime(timeout, 2650 c->notbefore); 2651 } 2652 } 2653 channel_garbage_collect(ssh, c); 2654 } 2655 } 2656 2657 /* 2658 * Create sockets before preparing IO. 2659 * This is necessary for things that need to happen after reading 2660 * the network-input but need to be completed before IO event setup, e.g. 2661 * because they may create new channels. 2662 */ 2663 static void 2664 channel_before_prepare_io(struct ssh *ssh) 2665 { 2666 struct ssh_channels *sc = ssh->chanctxt; 2667 Channel *c; 2668 u_int i, oalloc; 2669 2670 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2671 c = sc->channels[i]; 2672 if (c == NULL) 2673 continue; 2674 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2675 channel_before_prepare_io_rdynamic(ssh, c); 2676 } 2677 } 2678 2679 static void 2680 dump_channel_poll(const char *func, const char *what, Channel *c, 2681 u_int pollfd_offset, struct pollfd *pfd) 2682 { 2683 #ifdef DEBUG_CHANNEL_POLL 2684 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2685 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2686 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2687 c->rfd, c->wfd, c->efd, c->sock, 2688 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2689 c->io_want, c->io_ready, 2690 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2691 #endif 2692 } 2693 2694 /* Prepare pollfd entries for a single channel */ 2695 static void 2696 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2697 struct pollfd *pfd, u_int npfd) 2698 { 2699 u_int ev, p = *next_pollfd; 2700 2701 if (c == NULL) 2702 return; 2703 if (p + 4 > npfd) { 2704 /* Shouldn't happen */ 2705 fatal_f("channel %d: bad pfd offset %u (max %u)", 2706 c->self, p, npfd); 2707 } 2708 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2709 /* 2710 * prepare c->rfd 2711 * 2712 * This is a special case, since c->rfd might be the same as 2713 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2714 * IO too. 2715 */ 2716 if (c->rfd != -1) { 2717 ev = 0; 2718 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2719 ev |= POLLIN; 2720 /* rfd == wfd */ 2721 if (c->wfd == c->rfd) { 2722 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2723 ev |= POLLOUT; 2724 } 2725 /* rfd == efd */ 2726 if (c->efd == c->rfd) { 2727 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2728 ev |= POLLIN; 2729 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2730 ev |= POLLOUT; 2731 } 2732 /* rfd == sock */ 2733 if (c->sock == c->rfd) { 2734 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2735 ev |= POLLIN; 2736 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2737 ev |= POLLOUT; 2738 } 2739 /* Pack a pfd entry if any event armed for this fd */ 2740 if (ev != 0) { 2741 c->pfds[0] = p; 2742 pfd[p].fd = c->rfd; 2743 pfd[p].events = ev; 2744 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2745 p++; 2746 } 2747 } 2748 /* prepare c->wfd if wanting IO and not already handled above */ 2749 if (c->wfd != -1 && c->rfd != c->wfd) { 2750 ev = 0; 2751 if ((c->io_want & SSH_CHAN_IO_WFD)) 2752 ev |= POLLOUT; 2753 /* Pack a pfd entry if any event armed for this fd */ 2754 if (ev != 0) { 2755 c->pfds[1] = p; 2756 pfd[p].fd = c->wfd; 2757 pfd[p].events = ev; 2758 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2759 p++; 2760 } 2761 } 2762 /* prepare c->efd if wanting IO and not already handled above */ 2763 if (c->efd != -1 && c->rfd != c->efd) { 2764 ev = 0; 2765 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2766 ev |= POLLIN; 2767 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2768 ev |= POLLOUT; 2769 /* Pack a pfd entry if any event armed for this fd */ 2770 if (ev != 0) { 2771 c->pfds[2] = p; 2772 pfd[p].fd = c->efd; 2773 pfd[p].events = ev; 2774 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2775 p++; 2776 } 2777 } 2778 /* prepare c->sock if wanting IO and not already handled above */ 2779 if (c->sock != -1 && c->rfd != c->sock) { 2780 ev = 0; 2781 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2782 ev |= POLLIN; 2783 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2784 ev |= POLLOUT; 2785 /* Pack a pfd entry if any event armed for this fd */ 2786 if (ev != 0) { 2787 c->pfds[3] = p; 2788 pfd[p].fd = c->sock; 2789 pfd[p].events = 0; 2790 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2791 p++; 2792 } 2793 } 2794 *next_pollfd = p; 2795 } 2796 2797 /* * Allocate/prepare poll structure */ 2798 void 2799 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2800 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2801 { 2802 struct ssh_channels *sc = ssh->chanctxt; 2803 u_int i, oalloc, p, npfd = npfd_reserved; 2804 2805 channel_before_prepare_io(ssh); /* might create a new channel */ 2806 /* clear out I/O flags from last poll */ 2807 for (i = 0; i < sc->channels_alloc; i++) { 2808 if (sc->channels[i] == NULL) 2809 continue; 2810 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2811 } 2812 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2813 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2814 fatal_f("too many channels"); /* shouldn't happen */ 2815 npfd += sc->channels_alloc * 4; 2816 if (npfd > *npfd_allocp) { 2817 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2818 npfd, sizeof(**pfdp)); 2819 *npfd_allocp = npfd; 2820 } 2821 *npfd_activep = npfd_reserved; 2822 oalloc = sc->channels_alloc; 2823 2824 channel_handler(ssh, CHAN_PRE, timeout); 2825 2826 if (oalloc != sc->channels_alloc) { 2827 /* shouldn't happen */ 2828 fatal_f("channels_alloc changed during CHAN_PRE " 2829 "(was %u, now %u)", oalloc, sc->channels_alloc); 2830 } 2831 2832 /* Prepare pollfd */ 2833 p = npfd_reserved; 2834 for (i = 0; i < sc->channels_alloc; i++) 2835 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2836 *npfd_activep = p; 2837 } 2838 2839 static void 2840 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2841 const char *what, u_int revents_mask, u_int ready) 2842 { 2843 struct pollfd *pfd = &pfds[p]; 2844 2845 if (fd == -1) 2846 return; 2847 if (p == -1 || (u_int)p >= npfd) 2848 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2849 dump_channel_poll(__func__, what, c, p, pfd); 2850 if (pfd->fd != fd) { 2851 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2852 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2853 c->rfd, c->wfd, c->efd, c->sock); 2854 } 2855 if ((pfd->revents & POLLNVAL) != 0) { 2856 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2857 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2858 } 2859 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2860 c->io_ready |= ready & c->io_want; 2861 } 2862 2863 /* 2864 * After poll, perform any appropriate operations for channels which have 2865 * events pending. 2866 */ 2867 void 2868 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2869 { 2870 struct ssh_channels *sc = ssh->chanctxt; 2871 u_int i; 2872 int p; 2873 Channel *c; 2874 2875 #ifdef DEBUG_CHANNEL_POLL 2876 for (p = 0; p < (int)npfd; p++) { 2877 if (pfd[p].revents == 0) 2878 continue; 2879 debug_f("pfd[%u].fd %d rev 0x%04x", 2880 p, pfd[p].fd, pfd[p].revents); 2881 } 2882 #endif 2883 2884 /* Convert pollfd into c->io_ready */ 2885 for (i = 0; i < sc->channels_alloc; i++) { 2886 c = sc->channels[i]; 2887 if (c == NULL) 2888 continue; 2889 /* if rfd is shared with efd/sock then wfd should be too */ 2890 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2891 (c->rfd == c->efd || c->rfd == c->sock)) { 2892 /* Shouldn't happen */ 2893 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2894 c->self, c->rfd, c->wfd, c->efd, c->sock); 2895 } 2896 c->io_ready = 0; 2897 /* rfd, potentially shared with wfd, efd and sock */ 2898 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2899 fd_ready(c, p, pfd, npfd, c->rfd, 2900 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2901 if (c->rfd == c->wfd) { 2902 fd_ready(c, p, pfd, npfd, c->wfd, 2903 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2904 } 2905 if (c->rfd == c->efd) { 2906 fd_ready(c, p, pfd, npfd, c->efd, 2907 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2908 fd_ready(c, p, pfd, npfd, c->efd, 2909 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2910 } 2911 if (c->rfd == c->sock) { 2912 fd_ready(c, p, pfd, npfd, c->sock, 2913 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2914 fd_ready(c, p, pfd, npfd, c->sock, 2915 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2916 } 2917 dump_channel_poll(__func__, "rfd", c, p, pfd); 2918 } 2919 /* wfd */ 2920 if (c->wfd != -1 && c->wfd != c->rfd && 2921 (p = c->pfds[1]) != -1) { 2922 fd_ready(c, p, pfd, npfd, c->wfd, 2923 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2924 dump_channel_poll(__func__, "wfd", c, p, pfd); 2925 } 2926 /* efd */ 2927 if (c->efd != -1 && c->efd != c->rfd && 2928 (p = c->pfds[2]) != -1) { 2929 fd_ready(c, p, pfd, npfd, c->efd, 2930 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2931 fd_ready(c, p, pfd, npfd, c->efd, 2932 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2933 dump_channel_poll(__func__, "efd", c, p, pfd); 2934 } 2935 /* sock */ 2936 if (c->sock != -1 && c->sock != c->rfd && 2937 (p = c->pfds[3]) != -1) { 2938 fd_ready(c, p, pfd, npfd, c->sock, 2939 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2940 fd_ready(c, p, pfd, npfd, c->sock, 2941 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2942 dump_channel_poll(__func__, "sock", c, p, pfd); 2943 } 2944 } 2945 channel_handler(ssh, CHAN_POST, NULL); 2946 } 2947 2948 /* 2949 * Enqueue data for channels with open or draining c->input. 2950 * Returns non-zero if a packet was enqueued. 2951 */ 2952 static int 2953 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2954 { 2955 size_t len, plen; 2956 const u_char *pkt; 2957 int r; 2958 2959 if ((len = sshbuf_len(c->input)) == 0) { 2960 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2961 /* 2962 * input-buffer is empty and read-socket shutdown: 2963 * tell peer, that we will not send more data: 2964 * send IEOF. 2965 * hack for extended data: delay EOF if EFD still 2966 * in use. 2967 */ 2968 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2969 debug2("channel %d: " 2970 "ibuf_empty delayed efd %d/(%zu)", 2971 c->self, c->efd, sshbuf_len(c->extended)); 2972 else 2973 chan_ibuf_empty(ssh, c); 2974 } 2975 return 0; 2976 } 2977 2978 if (!c->have_remote_id) 2979 fatal_f("channel %d: no remote id", c->self); 2980 2981 if (c->datagram) { 2982 /* Check datagram will fit; drop if not */ 2983 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2984 fatal_fr(r, "channel %i: get datagram", c->self); 2985 /* 2986 * XXX this does tail-drop on the datagram queue which is 2987 * usually suboptimal compared to head-drop. Better to have 2988 * backpressure at read time? (i.e. read + discard) 2989 */ 2990 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2991 debug("channel %d: datagram too big", c->self); 2992 return 0; 2993 } 2994 /* Enqueue it */ 2995 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2996 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2997 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2998 (r = sshpkt_send(ssh)) != 0) 2999 fatal_fr(r, "channel %i: send datagram", c->self); 3000 c->remote_window -= plen; 3001 return 1; 3002 } 3003 3004 /* Enqueue packet for buffered data. */ 3005 if (len > c->remote_window) 3006 len = c->remote_window; 3007 if (len > c->remote_maxpacket) 3008 len = c->remote_maxpacket; 3009 if (len == 0) 3010 return 0; 3011 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 3012 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3013 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 3014 (r = sshpkt_send(ssh)) != 0) 3015 fatal_fr(r, "channel %i: send data", c->self); 3016 if ((r = sshbuf_consume(c->input, len)) != 0) 3017 fatal_fr(r, "channel %i: consume", c->self); 3018 c->remote_window -= len; 3019 return 1; 3020 } 3021 3022 /* 3023 * Enqueue data for channels with open c->extended in read mode. 3024 * Returns non-zero if a packet was enqueued. 3025 */ 3026 static int 3027 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 3028 { 3029 size_t len; 3030 int r; 3031 3032 if ((len = sshbuf_len(c->extended)) == 0) 3033 return 0; 3034 3035 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 3036 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 3037 if (len > c->remote_window) 3038 len = c->remote_window; 3039 if (len > c->remote_maxpacket) 3040 len = c->remote_maxpacket; 3041 if (len == 0) 3042 return 0; 3043 if (!c->have_remote_id) 3044 fatal_f("channel %d: no remote id", c->self); 3045 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 3046 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3047 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 3048 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 3049 (r = sshpkt_send(ssh)) != 0) 3050 fatal_fr(r, "channel %i: data", c->self); 3051 if ((r = sshbuf_consume(c->extended, len)) != 0) 3052 fatal_fr(r, "channel %i: consume", c->self); 3053 c->remote_window -= len; 3054 debug2("channel %d: sent ext data %zu", c->self, len); 3055 return 1; 3056 } 3057 3058 /* 3059 * If there is data to send to the connection, enqueue some of it now. 3060 * Returns non-zero if data was enqueued. 3061 */ 3062 int 3063 channel_output_poll(struct ssh *ssh) 3064 { 3065 struct ssh_channels *sc = ssh->chanctxt; 3066 Channel *c; 3067 u_int i; 3068 int ret = 0; 3069 3070 for (i = 0; i < sc->channels_alloc; i++) { 3071 c = sc->channels[i]; 3072 if (c == NULL) 3073 continue; 3074 3075 /* 3076 * We are only interested in channels that can have buffered 3077 * incoming data. 3078 */ 3079 if (c->type != SSH_CHANNEL_OPEN) 3080 continue; 3081 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3082 /* XXX is this true? */ 3083 debug3("channel %d: will not send data after close", 3084 c->self); 3085 continue; 3086 } 3087 3088 /* Get the amount of buffered data for this channel. */ 3089 if (c->istate == CHAN_INPUT_OPEN || 3090 c->istate == CHAN_INPUT_WAIT_DRAIN) 3091 ret |= channel_output_poll_input_open(ssh, c); 3092 /* Send extended data, i.e. stderr */ 3093 if (!(c->flags & CHAN_EOF_SENT) && 3094 c->extended_usage == CHAN_EXTENDED_READ) 3095 ret |= channel_output_poll_extended_read(ssh, c); 3096 } 3097 return ret; 3098 } 3099 3100 /* -- mux proxy support */ 3101 3102 /* 3103 * When multiplexing channel messages for mux clients we have to deal 3104 * with downstream messages from the mux client and upstream messages 3105 * from the ssh server: 3106 * 1) Handling downstream messages is straightforward and happens 3107 * in channel_proxy_downstream(): 3108 * - We forward all messages (mostly) unmodified to the server. 3109 * - However, in order to route messages from upstream to the correct 3110 * downstream client, we have to replace the channel IDs used by the 3111 * mux clients with a unique channel ID because the mux clients might 3112 * use conflicting channel IDs. 3113 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3114 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3115 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3116 * with the newly allocated channel ID. 3117 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3118 * channels and processed by channel_proxy_upstream(). The local channel ID 3119 * is then translated back to the original mux client ID. 3120 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3121 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3122 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3123 * downstream mux client are removed. 3124 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3125 * requires more work, because they are not addressed to a specific 3126 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3127 * out whether the request is addressed to the local client or a 3128 * specific downstream client based on the listen-address/port. 3129 * 6) Agent and X11-Forwarding have a similar problem and are currently 3130 * not supported as the matching session/channel cannot be identified 3131 * easily. 3132 */ 3133 3134 /* 3135 * receive packets from downstream mux clients: 3136 * channel callback fired on read from mux client, creates 3137 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3138 * on channel creation. 3139 */ 3140 int 3141 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3142 { 3143 Channel *c = NULL; 3144 struct sshbuf *original = NULL, *modified = NULL; 3145 const u_char *cp; 3146 char *ctype = NULL, *listen_host = NULL; 3147 u_char type; 3148 size_t have; 3149 int ret = -1, r; 3150 u_int id, remote_id, listen_port; 3151 3152 /* sshbuf_dump(downstream->input, stderr); */ 3153 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3154 != 0) { 3155 error_fr(r, "parse"); 3156 return -1; 3157 } 3158 if (have < 2) { 3159 error_f("short message"); 3160 return -1; 3161 } 3162 type = cp[1]; 3163 /* skip padlen + type */ 3164 cp += 2; 3165 have -= 2; 3166 if (ssh_packet_log_type(type)) 3167 debug3_f("channel %u: down->up: type %u", 3168 downstream->self, type); 3169 3170 switch (type) { 3171 case SSH2_MSG_CHANNEL_OPEN: 3172 if ((original = sshbuf_from(cp, have)) == NULL || 3173 (modified = sshbuf_new()) == NULL) { 3174 error_f("alloc"); 3175 goto out; 3176 } 3177 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3178 (r = sshbuf_get_u32(original, &id)) != 0) { 3179 error_fr(r, "parse"); 3180 goto out; 3181 } 3182 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3183 -1, -1, -1, 0, 0, 0, ctype, 1); 3184 c->mux_ctx = downstream; /* point to mux client */ 3185 c->mux_downstream_id = id; /* original downstream id */ 3186 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3187 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3188 (r = sshbuf_putb(modified, original)) != 0) { 3189 error_fr(r, "compose"); 3190 channel_free(ssh, c); 3191 goto out; 3192 } 3193 break; 3194 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3195 /* 3196 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3197 * need to parse 'remote_id' instead of 'ctype'. 3198 */ 3199 if ((original = sshbuf_from(cp, have)) == NULL || 3200 (modified = sshbuf_new()) == NULL) { 3201 error_f("alloc"); 3202 goto out; 3203 } 3204 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3205 (r = sshbuf_get_u32(original, &id)) != 0) { 3206 error_fr(r, "parse"); 3207 goto out; 3208 } 3209 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3210 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3211 c->mux_ctx = downstream; /* point to mux client */ 3212 c->mux_downstream_id = id; 3213 c->remote_id = remote_id; 3214 c->have_remote_id = 1; 3215 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3216 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3217 (r = sshbuf_putb(modified, original)) != 0) { 3218 error_fr(r, "compose"); 3219 channel_free(ssh, c); 3220 goto out; 3221 } 3222 break; 3223 case SSH2_MSG_GLOBAL_REQUEST: 3224 if ((original = sshbuf_from(cp, have)) == NULL) { 3225 error_f("alloc"); 3226 goto out; 3227 } 3228 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3229 error_fr(r, "parse"); 3230 goto out; 3231 } 3232 if (strcmp(ctype, "tcpip-forward") != 0) { 3233 error_f("unsupported request %s", ctype); 3234 goto out; 3235 } 3236 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3237 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3238 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3239 error_fr(r, "parse"); 3240 goto out; 3241 } 3242 if (listen_port > 65535) { 3243 error_f("tcpip-forward for %s: bad port %u", 3244 listen_host, listen_port); 3245 goto out; 3246 } 3247 /* Record that connection to this host/port is permitted. */ 3248 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", 3249 -1, listen_host, NULL, (int)listen_port, downstream); 3250 break; 3251 case SSH2_MSG_CHANNEL_CLOSE: 3252 if (have < 4) 3253 break; 3254 remote_id = PEEK_U32(cp); 3255 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3256 if (c->flags & CHAN_CLOSE_RCVD) 3257 channel_free(ssh, c); 3258 else 3259 c->flags |= CHAN_CLOSE_SENT; 3260 } 3261 break; 3262 } 3263 if (modified) { 3264 if ((r = sshpkt_start(ssh, type)) != 0 || 3265 (r = sshpkt_putb(ssh, modified)) != 0 || 3266 (r = sshpkt_send(ssh)) != 0) { 3267 error_fr(r, "send"); 3268 goto out; 3269 } 3270 } else { 3271 if ((r = sshpkt_start(ssh, type)) != 0 || 3272 (r = sshpkt_put(ssh, cp, have)) != 0 || 3273 (r = sshpkt_send(ssh)) != 0) { 3274 error_fr(r, "send"); 3275 goto out; 3276 } 3277 } 3278 ret = 0; 3279 out: 3280 free(ctype); 3281 free(listen_host); 3282 sshbuf_free(original); 3283 sshbuf_free(modified); 3284 return ret; 3285 } 3286 3287 /* 3288 * receive packets from upstream server and de-multiplex packets 3289 * to correct downstream: 3290 * implemented as a helper for channel input handlers, 3291 * replaces local (proxy) channel ID with downstream channel ID. 3292 */ 3293 int 3294 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3295 { 3296 struct sshbuf *b = NULL; 3297 Channel *downstream; 3298 const u_char *cp = NULL; 3299 size_t len; 3300 int r; 3301 3302 /* 3303 * When receiving packets from the peer we need to check whether we 3304 * need to forward the packets to the mux client. In this case we 3305 * restore the original channel id and keep track of CLOSE messages, 3306 * so we can cleanup the channel. 3307 */ 3308 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3309 return 0; 3310 if ((downstream = c->mux_ctx) == NULL) 3311 return 0; 3312 switch (type) { 3313 case SSH2_MSG_CHANNEL_CLOSE: 3314 case SSH2_MSG_CHANNEL_DATA: 3315 case SSH2_MSG_CHANNEL_EOF: 3316 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3317 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3318 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3319 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3320 case SSH2_MSG_CHANNEL_SUCCESS: 3321 case SSH2_MSG_CHANNEL_FAILURE: 3322 case SSH2_MSG_CHANNEL_REQUEST: 3323 break; 3324 default: 3325 debug2_f("channel %u: unsupported type %u", c->self, type); 3326 return 0; 3327 } 3328 if ((b = sshbuf_new()) == NULL) { 3329 error_f("alloc reply"); 3330 goto out; 3331 } 3332 /* get remaining payload (after id) */ 3333 cp = sshpkt_ptr(ssh, &len); 3334 if (cp == NULL) { 3335 error_f("no packet"); 3336 goto out; 3337 } 3338 /* translate id and send to muxclient */ 3339 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3340 (r = sshbuf_put_u8(b, type)) != 0 || 3341 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3342 (r = sshbuf_put(b, cp, len)) != 0 || 3343 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3344 error_fr(r, "compose muxclient"); 3345 goto out; 3346 } 3347 /* sshbuf_dump(b, stderr); */ 3348 if (ssh_packet_log_type(type)) 3349 debug3_f("channel %u: up->down: type %u", c->self, type); 3350 out: 3351 /* update state */ 3352 switch (type) { 3353 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3354 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3355 if (cp && len > 4) { 3356 c->remote_id = PEEK_U32(cp); 3357 c->have_remote_id = 1; 3358 } 3359 break; 3360 case SSH2_MSG_CHANNEL_CLOSE: 3361 if (c->flags & CHAN_CLOSE_SENT) 3362 channel_free(ssh, c); 3363 else 3364 c->flags |= CHAN_CLOSE_RCVD; 3365 break; 3366 } 3367 sshbuf_free(b); 3368 return 1; 3369 } 3370 3371 /* -- protocol input */ 3372 3373 /* Parse a channel ID from the current packet */ 3374 static int 3375 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3376 { 3377 u_int32_t id; 3378 int r; 3379 3380 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3381 error_r(r, "%s: parse id", where); 3382 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3383 } 3384 if (id > INT_MAX) { 3385 error_r(r, "%s: bad channel id %u", where, id); 3386 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3387 } 3388 return (int)id; 3389 } 3390 3391 /* Lookup a channel from an ID in the current packet */ 3392 static Channel * 3393 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3394 { 3395 int id = channel_parse_id(ssh, where, what); 3396 Channel *c; 3397 3398 if ((c = channel_lookup(ssh, id)) == NULL) { 3399 ssh_packet_disconnect(ssh, 3400 "%s packet referred to nonexistent channel %d", what, id); 3401 } 3402 return c; 3403 } 3404 3405 int 3406 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3407 { 3408 const u_char *data; 3409 size_t data_len, win_len; 3410 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3411 int r; 3412 3413 if (channel_proxy_upstream(c, type, seq, ssh)) 3414 return 0; 3415 3416 /* Ignore any data for non-open channels (might happen on close) */ 3417 if (c->type != SSH_CHANNEL_OPEN && 3418 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3419 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3420 c->type != SSH_CHANNEL_X11_OPEN) 3421 return 0; 3422 3423 /* Get the data. */ 3424 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3425 (r = sshpkt_get_end(ssh)) != 0) 3426 fatal_fr(r, "channel %i: get data", c->self); 3427 3428 win_len = data_len; 3429 if (c->datagram) 3430 win_len += 4; /* string length header */ 3431 3432 /* 3433 * The sending side reduces its window as it sends data, so we 3434 * must 'fake' consumption of the data in order to ensure that window 3435 * updates are sent back. Otherwise the connection might deadlock. 3436 */ 3437 if (c->ostate != CHAN_OUTPUT_OPEN) { 3438 c->local_window -= win_len; 3439 c->local_consumed += win_len; 3440 return 0; 3441 } 3442 3443 if (win_len > c->local_maxpacket) { 3444 logit("channel %d: rcvd big packet %zu, maxpack %u", 3445 c->self, win_len, c->local_maxpacket); 3446 return 0; 3447 } 3448 if (win_len > c->local_window) { 3449 c->local_window_exceeded += win_len - c->local_window; 3450 logit("channel %d: rcvd too much data %zu, win %u/%u " 3451 "(excess %u)", c->self, win_len, c->local_window, 3452 c->local_window_max, c->local_window_exceeded); 3453 c->local_window = 0; 3454 /* Allow 10% grace before bringing the hammer down */ 3455 if (c->local_window_exceeded > (c->local_window_max / 10)) { 3456 ssh_packet_disconnect(ssh, "channel %d: peer ignored " 3457 "channel window", c->self); 3458 } 3459 } else { 3460 c->local_window -= win_len; 3461 c->local_window_exceeded = 0; 3462 } 3463 3464 if (c->datagram) { 3465 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3466 fatal_fr(r, "channel %i: append datagram", c->self); 3467 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3468 fatal_fr(r, "channel %i: append data", c->self); 3469 3470 return 0; 3471 } 3472 3473 int 3474 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3475 { 3476 const u_char *data; 3477 size_t data_len; 3478 u_int32_t tcode; 3479 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3480 int r; 3481 3482 if (channel_proxy_upstream(c, type, seq, ssh)) 3483 return 0; 3484 if (c->type != SSH_CHANNEL_OPEN) { 3485 logit("channel %d: ext data for non open", c->self); 3486 return 0; 3487 } 3488 if (c->flags & CHAN_EOF_RCVD) { 3489 if (ssh->compat & SSH_BUG_EXTEOF) 3490 debug("channel %d: accepting ext data after eof", 3491 c->self); 3492 else 3493 ssh_packet_disconnect(ssh, "Received extended_data " 3494 "after EOF on channel %d.", c->self); 3495 } 3496 3497 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3498 error_fr(r, "parse tcode"); 3499 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3500 } 3501 if (c->efd == -1 || 3502 c->extended_usage != CHAN_EXTENDED_WRITE || 3503 tcode != SSH2_EXTENDED_DATA_STDERR) { 3504 logit("channel %d: bad ext data", c->self); 3505 return 0; 3506 } 3507 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3508 (r = sshpkt_get_end(ssh)) != 0) { 3509 error_fr(r, "parse data"); 3510 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3511 } 3512 3513 if (data_len > c->local_window) { 3514 logit("channel %d: rcvd too much extended_data %zu, win %u", 3515 c->self, data_len, c->local_window); 3516 return 0; 3517 } 3518 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3519 /* XXX sshpkt_getb? */ 3520 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3521 error_fr(r, "append"); 3522 c->local_window -= data_len; 3523 return 0; 3524 } 3525 3526 int 3527 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3528 { 3529 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3530 int r; 3531 3532 if ((r = sshpkt_get_end(ssh)) != 0) { 3533 error_fr(r, "parse data"); 3534 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3535 } 3536 3537 if (channel_proxy_upstream(c, type, seq, ssh)) 3538 return 0; 3539 chan_rcvd_ieof(ssh, c); 3540 3541 /* XXX force input close */ 3542 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3543 debug("channel %d: FORCE input drain", c->self); 3544 c->istate = CHAN_INPUT_WAIT_DRAIN; 3545 if (sshbuf_len(c->input) == 0) 3546 chan_ibuf_empty(ssh, c); 3547 } 3548 return 0; 3549 } 3550 3551 int 3552 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3553 { 3554 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3555 int r; 3556 3557 if (channel_proxy_upstream(c, type, seq, ssh)) 3558 return 0; 3559 if ((r = sshpkt_get_end(ssh)) != 0) { 3560 error_fr(r, "parse data"); 3561 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3562 } 3563 chan_rcvd_oclose(ssh, c); 3564 return 0; 3565 } 3566 3567 int 3568 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3569 { 3570 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3571 u_int32_t remote_window, remote_maxpacket; 3572 int r; 3573 3574 if (channel_proxy_upstream(c, type, seq, ssh)) 3575 return 0; 3576 if (c->type != SSH_CHANNEL_OPENING) 3577 ssh_packet_disconnect(ssh, "Received open confirmation for " 3578 "non-opening channel %d.", c->self); 3579 /* 3580 * Record the remote channel number and mark that the channel 3581 * is now open. 3582 */ 3583 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3584 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3585 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3586 (r = sshpkt_get_end(ssh)) != 0) { 3587 error_fr(r, "window/maxpacket"); 3588 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3589 } 3590 3591 c->have_remote_id = 1; 3592 c->remote_window = remote_window; 3593 c->remote_maxpacket = remote_maxpacket; 3594 c->type = SSH_CHANNEL_OPEN; 3595 if (c->open_confirm) { 3596 debug2_f("channel %d: callback start", c->self); 3597 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3598 debug2_f("channel %d: callback done", c->self); 3599 } 3600 channel_set_used_time(ssh, c); 3601 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3602 c->remote_window, c->remote_maxpacket); 3603 return 0; 3604 } 3605 3606 static char * 3607 reason2txt(int reason) 3608 { 3609 switch (reason) { 3610 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3611 return "administratively prohibited"; 3612 case SSH2_OPEN_CONNECT_FAILED: 3613 return "connect failed"; 3614 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3615 return "unknown channel type"; 3616 case SSH2_OPEN_RESOURCE_SHORTAGE: 3617 return "resource shortage"; 3618 } 3619 return "unknown reason"; 3620 } 3621 3622 int 3623 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3624 { 3625 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3626 u_int32_t reason; 3627 char *msg = NULL; 3628 int r; 3629 3630 if (channel_proxy_upstream(c, type, seq, ssh)) 3631 return 0; 3632 if (c->type != SSH_CHANNEL_OPENING) 3633 ssh_packet_disconnect(ssh, "Received open failure for " 3634 "non-opening channel %d.", c->self); 3635 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3636 error_fr(r, "parse reason"); 3637 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3638 } 3639 /* skip language */ 3640 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3641 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3642 (r = sshpkt_get_end(ssh)) != 0) { 3643 error_fr(r, "parse msg/lang"); 3644 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3645 } 3646 logit("channel %d: open failed: %s%s%s", c->self, 3647 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3648 free(msg); 3649 if (c->open_confirm) { 3650 debug2_f("channel %d: callback start", c->self); 3651 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3652 debug2_f("channel %d: callback done", c->self); 3653 } 3654 /* Schedule the channel for cleanup/deletion. */ 3655 chan_mark_dead(ssh, c); 3656 return 0; 3657 } 3658 3659 int 3660 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3661 { 3662 int id = channel_parse_id(ssh, __func__, "window adjust"); 3663 Channel *c; 3664 u_int32_t adjust; 3665 u_int new_rwin; 3666 int r; 3667 3668 if ((c = channel_lookup(ssh, id)) == NULL) { 3669 logit("Received window adjust for non-open channel %d.", id); 3670 return 0; 3671 } 3672 3673 if (channel_proxy_upstream(c, type, seq, ssh)) 3674 return 0; 3675 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3676 (r = sshpkt_get_end(ssh)) != 0) { 3677 error_fr(r, "parse adjust"); 3678 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3679 } 3680 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3681 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3682 fatal("channel %d: adjust %u overflows remote window %u", 3683 c->self, adjust, c->remote_window); 3684 } 3685 c->remote_window = new_rwin; 3686 return 0; 3687 } 3688 3689 int 3690 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3691 { 3692 int id = channel_parse_id(ssh, __func__, "status confirm"); 3693 Channel *c; 3694 struct channel_confirm *cc; 3695 3696 /* Reset keepalive timeout */ 3697 ssh_packet_set_alive_timeouts(ssh, 0); 3698 3699 debug2_f("type %d id %d", type, id); 3700 3701 if ((c = channel_lookup(ssh, id)) == NULL) { 3702 logit_f("%d: unknown", id); 3703 return 0; 3704 } 3705 if (channel_proxy_upstream(c, type, seq, ssh)) 3706 return 0; 3707 if (sshpkt_get_end(ssh) != 0) 3708 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3709 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3710 return 0; 3711 cc->cb(ssh, type, c, cc->ctx); 3712 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3713 freezero(cc, sizeof(*cc)); 3714 return 0; 3715 } 3716 3717 /* -- tcp forwarding */ 3718 3719 void 3720 channel_set_af(struct ssh *ssh, int af) 3721 { 3722 ssh->chanctxt->IPv4or6 = af; 3723 } 3724 3725 3726 /* 3727 * Determine whether or not a port forward listens to loopback, the 3728 * specified address or wildcard. On the client, a specified bind 3729 * address will always override gateway_ports. On the server, a 3730 * gateway_ports of 1 (``yes'') will override the client's specification 3731 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3732 * will bind to whatever address the client asked for. 3733 * 3734 * Special-case listen_addrs are: 3735 * 3736 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3737 * "" (empty string), "*" -> wildcard v4/v6 3738 * "localhost" -> loopback v4/v6 3739 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3740 */ 3741 static const char * 3742 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3743 int is_client, struct ForwardOptions *fwd_opts) 3744 { 3745 const char *addr = NULL; 3746 int wildcard = 0; 3747 3748 if (listen_addr == NULL) { 3749 /* No address specified: default to gateway_ports setting */ 3750 if (fwd_opts->gateway_ports) 3751 wildcard = 1; 3752 } else if (fwd_opts->gateway_ports || is_client) { 3753 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3754 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3755 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3756 (!is_client && fwd_opts->gateway_ports == 1)) { 3757 wildcard = 1; 3758 /* 3759 * Notify client if they requested a specific listen 3760 * address and it was overridden. 3761 */ 3762 if (*listen_addr != '\0' && 3763 strcmp(listen_addr, "0.0.0.0") != 0 && 3764 strcmp(listen_addr, "*") != 0) { 3765 ssh_packet_send_debug(ssh, 3766 "Forwarding listen address " 3767 "\"%s\" overridden by server " 3768 "GatewayPorts", listen_addr); 3769 } 3770 } else if (strcmp(listen_addr, "localhost") != 0 || 3771 strcmp(listen_addr, "127.0.0.1") == 0 || 3772 strcmp(listen_addr, "::1") == 0) { 3773 /* 3774 * Accept explicit localhost address when 3775 * GatewayPorts=yes. The "localhost" hostname is 3776 * deliberately skipped here so it will listen on all 3777 * available local address families. 3778 */ 3779 addr = listen_addr; 3780 } 3781 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3782 strcmp(listen_addr, "::1") == 0) { 3783 /* 3784 * If a specific IPv4/IPv6 localhost address has been 3785 * requested then accept it even if gateway_ports is in 3786 * effect. This allows the client to prefer IPv4 or IPv6. 3787 */ 3788 addr = listen_addr; 3789 } 3790 if (wildcardp != NULL) 3791 *wildcardp = wildcard; 3792 return addr; 3793 } 3794 3795 static int 3796 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3797 struct Forward *fwd, int *allocated_listen_port, 3798 struct ForwardOptions *fwd_opts) 3799 { 3800 Channel *c; 3801 int sock, r, success = 0, wildcard = 0, is_client; 3802 struct addrinfo hints, *ai, *aitop; 3803 const char *host, *addr; 3804 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3805 in_port_t *lport_p; 3806 3807 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3808 3809 if (is_client && fwd->connect_path != NULL) { 3810 host = fwd->connect_path; 3811 } else { 3812 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3813 fwd->listen_host : fwd->connect_host; 3814 if (host == NULL) { 3815 error("No forward host name."); 3816 return 0; 3817 } 3818 if (strlen(host) >= NI_MAXHOST) { 3819 error("Forward host name too long."); 3820 return 0; 3821 } 3822 } 3823 3824 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3825 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3826 is_client, fwd_opts); 3827 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3828 (addr == NULL) ? "NULL" : addr); 3829 3830 /* 3831 * getaddrinfo returns a loopback address if the hostname is 3832 * set to NULL and hints.ai_flags is not AI_PASSIVE 3833 */ 3834 memset(&hints, 0, sizeof(hints)); 3835 hints.ai_family = ssh->chanctxt->IPv4or6; 3836 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3837 hints.ai_socktype = SOCK_STREAM; 3838 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3839 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3840 if (addr == NULL) { 3841 /* This really shouldn't happen */ 3842 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3843 ssh_gai_strerror(r)); 3844 } else { 3845 error_f("getaddrinfo(%.64s): %s", addr, 3846 ssh_gai_strerror(r)); 3847 } 3848 return 0; 3849 } 3850 if (allocated_listen_port != NULL) 3851 *allocated_listen_port = 0; 3852 for (ai = aitop; ai; ai = ai->ai_next) { 3853 switch (ai->ai_family) { 3854 case AF_INET: 3855 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3856 sin_port; 3857 break; 3858 case AF_INET6: 3859 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3860 sin6_port; 3861 break; 3862 default: 3863 continue; 3864 } 3865 /* 3866 * If allocating a port for -R forwards, then use the 3867 * same port for all address families. 3868 */ 3869 if (type == SSH_CHANNEL_RPORT_LISTENER && 3870 fwd->listen_port == 0 && allocated_listen_port != NULL && 3871 *allocated_listen_port > 0) 3872 *lport_p = htons(*allocated_listen_port); 3873 3874 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3875 strport, sizeof(strport), 3876 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3877 error_f("getnameinfo failed"); 3878 continue; 3879 } 3880 /* Create a port to listen for the host. */ 3881 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3882 if (sock == -1) { 3883 /* this is no error since kernel may not support ipv6 */ 3884 verbose("socket [%s]:%s: %.100s", ntop, strport, 3885 strerror(errno)); 3886 continue; 3887 } 3888 3889 set_reuseaddr(sock); 3890 if (ai->ai_family == AF_INET6) 3891 sock_set_v6only(sock); 3892 3893 debug("Local forwarding listening on %s port %s.", 3894 ntop, strport); 3895 3896 /* Bind the socket to the address. */ 3897 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3898 /* 3899 * address can be in if use ipv6 address is 3900 * already bound 3901 */ 3902 if (!ai->ai_next) 3903 error("bind [%s]:%s: %.100s", 3904 ntop, strport, strerror(errno)); 3905 else 3906 verbose("bind [%s]:%s: %.100s", 3907 ntop, strport, strerror(errno)); 3908 3909 close(sock); 3910 continue; 3911 } 3912 /* Start listening for connections on the socket. */ 3913 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3914 error("listen [%s]:%s: %.100s", ntop, strport, 3915 strerror(errno)); 3916 close(sock); 3917 continue; 3918 } 3919 3920 /* 3921 * fwd->listen_port == 0 requests a dynamically allocated port - 3922 * record what we got. 3923 */ 3924 if (type == SSH_CHANNEL_RPORT_LISTENER && 3925 fwd->listen_port == 0 && 3926 allocated_listen_port != NULL && 3927 *allocated_listen_port == 0) { 3928 *allocated_listen_port = get_local_port(sock); 3929 debug("Allocated listen port %d", 3930 *allocated_listen_port); 3931 } 3932 3933 /* Allocate a channel number for the socket. */ 3934 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3935 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3936 0, "port listener", 1); 3937 c->path = xstrdup(host); 3938 c->host_port = fwd->connect_port; 3939 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3940 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3941 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3942 c->listening_port = *allocated_listen_port; 3943 else 3944 c->listening_port = fwd->listen_port; 3945 success = 1; 3946 } 3947 if (success == 0) 3948 error_f("cannot listen to port: %d", fwd->listen_port); 3949 freeaddrinfo(aitop); 3950 return success; 3951 } 3952 3953 static int 3954 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3955 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3956 { 3957 struct sockaddr_un sunaddr; 3958 const char *path; 3959 Channel *c; 3960 int port, sock; 3961 mode_t omask; 3962 3963 switch (type) { 3964 case SSH_CHANNEL_UNIX_LISTENER: 3965 if (fwd->connect_path != NULL) { 3966 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3967 error("Local connecting path too long: %s", 3968 fwd->connect_path); 3969 return 0; 3970 } 3971 path = fwd->connect_path; 3972 port = PORT_STREAMLOCAL; 3973 } else { 3974 if (fwd->connect_host == NULL) { 3975 error("No forward host name."); 3976 return 0; 3977 } 3978 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3979 error("Forward host name too long."); 3980 return 0; 3981 } 3982 path = fwd->connect_host; 3983 port = fwd->connect_port; 3984 } 3985 break; 3986 case SSH_CHANNEL_RUNIX_LISTENER: 3987 path = fwd->listen_path; 3988 port = PORT_STREAMLOCAL; 3989 break; 3990 default: 3991 error_f("unexpected channel type %d", type); 3992 return 0; 3993 } 3994 3995 if (fwd->listen_path == NULL) { 3996 error("No forward path name."); 3997 return 0; 3998 } 3999 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 4000 error("Local listening path too long: %s", fwd->listen_path); 4001 return 0; 4002 } 4003 4004 debug3_f("type %d path %s", type, fwd->listen_path); 4005 4006 /* Start a Unix domain listener. */ 4007 omask = umask(fwd_opts->streamlocal_bind_mask); 4008 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 4009 fwd_opts->streamlocal_bind_unlink); 4010 umask(omask); 4011 if (sock < 0) 4012 return 0; 4013 4014 debug("Local forwarding listening on path %s.", fwd->listen_path); 4015 4016 /* Allocate a channel number for the socket. */ 4017 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 4018 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 4019 0, "unix listener", 1); 4020 c->path = xstrdup(path); 4021 c->host_port = port; 4022 c->listening_port = PORT_STREAMLOCAL; 4023 c->listening_addr = xstrdup(fwd->listen_path); 4024 return 1; 4025 } 4026 4027 static int 4028 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 4029 const char *host, u_short port) 4030 { 4031 u_int i; 4032 int found = 0; 4033 4034 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4035 Channel *c = ssh->chanctxt->channels[i]; 4036 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 4037 continue; 4038 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 4039 debug2_f("close channel %d", i); 4040 channel_free(ssh, c); 4041 found = 1; 4042 } 4043 } 4044 4045 return found; 4046 } 4047 4048 static int 4049 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 4050 { 4051 u_int i; 4052 int found = 0; 4053 4054 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4055 Channel *c = ssh->chanctxt->channels[i]; 4056 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 4057 continue; 4058 if (c->path == NULL) 4059 continue; 4060 if (strcmp(c->path, path) == 0) { 4061 debug2_f("close channel %d", i); 4062 channel_free(ssh, c); 4063 found = 1; 4064 } 4065 } 4066 4067 return found; 4068 } 4069 4070 int 4071 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4072 { 4073 if (fwd->listen_path != NULL) { 4074 return channel_cancel_rport_listener_streamlocal(ssh, 4075 fwd->listen_path); 4076 } else { 4077 return channel_cancel_rport_listener_tcpip(ssh, 4078 fwd->listen_host, fwd->listen_port); 4079 } 4080 } 4081 4082 static int 4083 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4084 const char *lhost, u_short lport, int cport, 4085 struct ForwardOptions *fwd_opts) 4086 { 4087 u_int i; 4088 int found = 0; 4089 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4090 4091 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4092 Channel *c = ssh->chanctxt->channels[i]; 4093 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4094 continue; 4095 if (c->listening_port != lport) 4096 continue; 4097 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4098 /* skip dynamic forwardings */ 4099 if (c->host_port == 0) 4100 continue; 4101 } else { 4102 if (c->host_port != cport) 4103 continue; 4104 } 4105 if ((c->listening_addr == NULL && addr != NULL) || 4106 (c->listening_addr != NULL && addr == NULL)) 4107 continue; 4108 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4109 debug2_f("close channel %d", i); 4110 channel_free(ssh, c); 4111 found = 1; 4112 } 4113 } 4114 4115 return found; 4116 } 4117 4118 static int 4119 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4120 { 4121 u_int i; 4122 int found = 0; 4123 4124 if (path == NULL) { 4125 error_f("no path specified."); 4126 return 0; 4127 } 4128 4129 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4130 Channel *c = ssh->chanctxt->channels[i]; 4131 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4132 continue; 4133 if (c->listening_addr == NULL) 4134 continue; 4135 if (strcmp(c->listening_addr, path) == 0) { 4136 debug2_f("close channel %d", i); 4137 channel_free(ssh, c); 4138 found = 1; 4139 } 4140 } 4141 4142 return found; 4143 } 4144 4145 int 4146 channel_cancel_lport_listener(struct ssh *ssh, 4147 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4148 { 4149 if (fwd->listen_path != NULL) { 4150 return channel_cancel_lport_listener_streamlocal(ssh, 4151 fwd->listen_path); 4152 } else { 4153 return channel_cancel_lport_listener_tcpip(ssh, 4154 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4155 } 4156 } 4157 4158 /* protocol local port fwd, used by ssh */ 4159 int 4160 channel_setup_local_fwd_listener(struct ssh *ssh, 4161 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4162 { 4163 if (fwd->listen_path != NULL) { 4164 return channel_setup_fwd_listener_streamlocal(ssh, 4165 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4166 } else { 4167 return channel_setup_fwd_listener_tcpip(ssh, 4168 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4169 } 4170 } 4171 4172 /* Matches a remote forwarding permission against a requested forwarding */ 4173 static int 4174 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4175 { 4176 int ret; 4177 char *lhost; 4178 4179 /* XXX add ACLs for streamlocal */ 4180 if (fwd->listen_path != NULL) 4181 return 1; 4182 4183 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4184 return 0; 4185 4186 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4187 allowed_open->listen_port != fwd->listen_port) 4188 return 0; 4189 4190 /* Match hostnames case-insensitively */ 4191 lhost = xstrdup(fwd->listen_host); 4192 lowercase(lhost); 4193 ret = match_pattern(lhost, allowed_open->listen_host); 4194 free(lhost); 4195 4196 return ret; 4197 } 4198 4199 /* Checks whether a requested remote forwarding is permitted */ 4200 static int 4201 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4202 { 4203 struct ssh_channels *sc = ssh->chanctxt; 4204 struct permission_set *pset = &sc->remote_perms; 4205 u_int i, permit, permit_adm = 1; 4206 struct permission *perm; 4207 4208 /* XXX apply GatewayPorts override before checking? */ 4209 4210 permit = pset->all_permitted; 4211 if (!permit) { 4212 for (i = 0; i < pset->num_permitted_user; i++) { 4213 perm = &pset->permitted_user[i]; 4214 if (remote_open_match(perm, fwd)) { 4215 permit = 1; 4216 break; 4217 } 4218 } 4219 } 4220 4221 if (pset->num_permitted_admin > 0) { 4222 permit_adm = 0; 4223 for (i = 0; i < pset->num_permitted_admin; i++) { 4224 perm = &pset->permitted_admin[i]; 4225 if (remote_open_match(perm, fwd)) { 4226 permit_adm = 1; 4227 break; 4228 } 4229 } 4230 } 4231 4232 return permit && permit_adm; 4233 } 4234 4235 /* protocol v2 remote port fwd, used by sshd */ 4236 int 4237 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4238 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4239 { 4240 if (!check_rfwd_permission(ssh, fwd)) { 4241 ssh_packet_send_debug(ssh, "port forwarding refused"); 4242 if (fwd->listen_path != NULL) 4243 /* XXX always allowed, see remote_open_match() */ 4244 logit("Received request from %.100s port %d to " 4245 "remote forward to path \"%.100s\", " 4246 "but the request was denied.", 4247 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4248 fwd->listen_path); 4249 else if(fwd->listen_host != NULL) 4250 logit("Received request from %.100s port %d to " 4251 "remote forward to host %.100s port %d, " 4252 "but the request was denied.", 4253 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4254 fwd->listen_host, fwd->listen_port ); 4255 else 4256 logit("Received request from %.100s port %d to remote " 4257 "forward, but the request was denied.", 4258 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4259 return 0; 4260 } 4261 if (fwd->listen_path != NULL) { 4262 return channel_setup_fwd_listener_streamlocal(ssh, 4263 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4264 } else { 4265 return channel_setup_fwd_listener_tcpip(ssh, 4266 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4267 fwd_opts); 4268 } 4269 } 4270 4271 /* 4272 * Translate the requested rfwd listen host to something usable for 4273 * this server. 4274 */ 4275 static const char * 4276 channel_rfwd_bind_host(const char *listen_host) 4277 { 4278 if (listen_host == NULL) { 4279 return "localhost"; 4280 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4281 return ""; 4282 } else 4283 return listen_host; 4284 } 4285 4286 /* 4287 * Initiate forwarding of connections to port "port" on remote host through 4288 * the secure channel to host:port from local side. 4289 * Returns handle (index) for updating the dynamic listen port with 4290 * channel_update_permission(). 4291 */ 4292 int 4293 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4294 { 4295 int r, success = 0, idx = -1; 4296 const char *host_to_connect, *listen_host, *listen_path; 4297 int port_to_connect, listen_port; 4298 4299 /* Send the forward request to the remote side. */ 4300 if (fwd->listen_path != NULL) { 4301 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4302 (r = sshpkt_put_cstring(ssh, 4303 "streamlocal-forward@openssh.com")) != 0 || 4304 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4305 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4306 (r = sshpkt_send(ssh)) != 0 || 4307 (r = ssh_packet_write_wait(ssh)) != 0) 4308 fatal_fr(r, "request streamlocal"); 4309 } else { 4310 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4311 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4312 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4313 (r = sshpkt_put_cstring(ssh, 4314 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4315 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4316 (r = sshpkt_send(ssh)) != 0 || 4317 (r = ssh_packet_write_wait(ssh)) != 0) 4318 fatal_fr(r, "request tcpip-forward"); 4319 } 4320 /* Assume that server accepts the request */ 4321 success = 1; 4322 if (success) { 4323 /* Record that connection to this host/port is permitted. */ 4324 host_to_connect = listen_host = listen_path = NULL; 4325 port_to_connect = listen_port = 0; 4326 if (fwd->connect_path != NULL) { 4327 host_to_connect = fwd->connect_path; 4328 port_to_connect = PORT_STREAMLOCAL; 4329 } else { 4330 host_to_connect = fwd->connect_host; 4331 port_to_connect = fwd->connect_port; 4332 } 4333 if (fwd->listen_path != NULL) { 4334 listen_path = fwd->listen_path; 4335 listen_port = PORT_STREAMLOCAL; 4336 } else { 4337 listen_host = fwd->listen_host; 4338 listen_port = fwd->listen_port; 4339 } 4340 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4341 host_to_connect, port_to_connect, 4342 listen_host, listen_path, listen_port, NULL); 4343 } 4344 return idx; 4345 } 4346 4347 static int 4348 open_match(struct permission *allowed_open, const char *requestedhost, 4349 int requestedport) 4350 { 4351 if (allowed_open->host_to_connect == NULL) 4352 return 0; 4353 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4354 allowed_open->port_to_connect != requestedport) 4355 return 0; 4356 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4357 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4358 return 0; 4359 return 1; 4360 } 4361 4362 /* 4363 * Note that in the listen host/port case 4364 * we don't support FWD_PERMIT_ANY_PORT and 4365 * need to translate between the configured-host (listen_host) 4366 * and what we've sent to the remote server (channel_rfwd_bind_host) 4367 */ 4368 static int 4369 open_listen_match_tcpip(struct permission *allowed_open, 4370 const char *requestedhost, u_short requestedport, int translate) 4371 { 4372 const char *allowed_host; 4373 4374 if (allowed_open->host_to_connect == NULL) 4375 return 0; 4376 if (allowed_open->listen_port != requestedport) 4377 return 0; 4378 if (!translate && allowed_open->listen_host == NULL && 4379 requestedhost == NULL) 4380 return 1; 4381 allowed_host = translate ? 4382 channel_rfwd_bind_host(allowed_open->listen_host) : 4383 allowed_open->listen_host; 4384 if (allowed_host == NULL || requestedhost == NULL || 4385 strcmp(allowed_host, requestedhost) != 0) 4386 return 0; 4387 return 1; 4388 } 4389 4390 static int 4391 open_listen_match_streamlocal(struct permission *allowed_open, 4392 const char *requestedpath) 4393 { 4394 if (allowed_open->host_to_connect == NULL) 4395 return 0; 4396 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4397 return 0; 4398 if (allowed_open->listen_path == NULL || 4399 strcmp(allowed_open->listen_path, requestedpath) != 0) 4400 return 0; 4401 return 1; 4402 } 4403 4404 /* 4405 * Request cancellation of remote forwarding of connection host:port from 4406 * local side. 4407 */ 4408 static int 4409 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4410 const char *host, u_short port) 4411 { 4412 struct ssh_channels *sc = ssh->chanctxt; 4413 struct permission_set *pset = &sc->local_perms; 4414 int r; 4415 u_int i; 4416 struct permission *perm = NULL; 4417 4418 for (i = 0; i < pset->num_permitted_user; i++) { 4419 perm = &pset->permitted_user[i]; 4420 if (open_listen_match_tcpip(perm, host, port, 0)) 4421 break; 4422 perm = NULL; 4423 } 4424 if (perm == NULL) { 4425 debug_f("requested forward not found"); 4426 return -1; 4427 } 4428 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4429 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4430 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4431 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4432 (r = sshpkt_put_u32(ssh, port)) != 0 || 4433 (r = sshpkt_send(ssh)) != 0) 4434 fatal_fr(r, "send cancel"); 4435 4436 fwd_perm_clear(perm); /* unregister */ 4437 4438 return 0; 4439 } 4440 4441 /* 4442 * Request cancellation of remote forwarding of Unix domain socket 4443 * path from local side. 4444 */ 4445 static int 4446 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4447 { 4448 struct ssh_channels *sc = ssh->chanctxt; 4449 struct permission_set *pset = &sc->local_perms; 4450 int r; 4451 u_int i; 4452 struct permission *perm = NULL; 4453 4454 for (i = 0; i < pset->num_permitted_user; i++) { 4455 perm = &pset->permitted_user[i]; 4456 if (open_listen_match_streamlocal(perm, path)) 4457 break; 4458 perm = NULL; 4459 } 4460 if (perm == NULL) { 4461 debug_f("requested forward not found"); 4462 return -1; 4463 } 4464 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4465 (r = sshpkt_put_cstring(ssh, 4466 "cancel-streamlocal-forward@openssh.com")) != 0 || 4467 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4468 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4469 (r = sshpkt_send(ssh)) != 0) 4470 fatal_fr(r, "send cancel"); 4471 4472 fwd_perm_clear(perm); /* unregister */ 4473 4474 return 0; 4475 } 4476 4477 /* 4478 * Request cancellation of remote forwarding of a connection from local side. 4479 */ 4480 int 4481 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4482 { 4483 if (fwd->listen_path != NULL) { 4484 return channel_request_rforward_cancel_streamlocal(ssh, 4485 fwd->listen_path); 4486 } else { 4487 return channel_request_rforward_cancel_tcpip(ssh, 4488 fwd->listen_host, 4489 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4490 } 4491 } 4492 4493 /* 4494 * Permits opening to any host/port if permitted_user[] is empty. This is 4495 * usually called by the server, because the user could connect to any port 4496 * anyway, and the server has no way to know but to trust the client anyway. 4497 */ 4498 void 4499 channel_permit_all(struct ssh *ssh, int where) 4500 { 4501 struct permission_set *pset = permission_set_get(ssh, where); 4502 4503 if (pset->num_permitted_user == 0) 4504 pset->all_permitted = 1; 4505 } 4506 4507 /* 4508 * Permit the specified host/port for forwarding. 4509 */ 4510 void 4511 channel_add_permission(struct ssh *ssh, int who, int where, 4512 char *host, int port) 4513 { 4514 int local = where == FORWARD_LOCAL; 4515 struct permission_set *pset = permission_set_get(ssh, where); 4516 4517 debug("allow %s forwarding to host %s port %d", 4518 fwd_ident(who, where), host, port); 4519 /* 4520 * Remote forwards set listen_host/port, local forwards set 4521 * host/port_to_connect. 4522 */ 4523 permission_set_add(ssh, who, where, 4524 local ? host : 0, local ? port : 0, 4525 local ? NULL : host, NULL, local ? 0 : port, NULL); 4526 pset->all_permitted = 0; 4527 } 4528 4529 /* 4530 * Administratively disable forwarding. 4531 */ 4532 void 4533 channel_disable_admin(struct ssh *ssh, int where) 4534 { 4535 channel_clear_permission(ssh, FORWARD_ADM, where); 4536 permission_set_add(ssh, FORWARD_ADM, where, 4537 NULL, 0, NULL, NULL, 0, NULL); 4538 } 4539 4540 /* 4541 * Clear a list of permitted opens. 4542 */ 4543 void 4544 channel_clear_permission(struct ssh *ssh, int who, int where) 4545 { 4546 struct permission **permp; 4547 u_int *npermp; 4548 4549 permission_set_get_array(ssh, who, where, &permp, &npermp); 4550 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4551 *npermp = 0; 4552 } 4553 4554 /* 4555 * Update the listen port for a dynamic remote forward, after 4556 * the actual 'newport' has been allocated. If 'newport' < 0 is 4557 * passed then they entry will be invalidated. 4558 */ 4559 void 4560 channel_update_permission(struct ssh *ssh, int idx, int newport) 4561 { 4562 struct permission_set *pset = &ssh->chanctxt->local_perms; 4563 4564 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4565 debug_f("index out of range: %d num_permitted_user %d", 4566 idx, pset->num_permitted_user); 4567 return; 4568 } 4569 debug("%s allowed port %d for forwarding to host %s port %d", 4570 newport > 0 ? "Updating" : "Removing", 4571 newport, 4572 pset->permitted_user[idx].host_to_connect, 4573 pset->permitted_user[idx].port_to_connect); 4574 if (newport <= 0) 4575 fwd_perm_clear(&pset->permitted_user[idx]); 4576 else { 4577 pset->permitted_user[idx].listen_port = 4578 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4579 } 4580 } 4581 4582 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4583 int 4584 permitopen_port(const char *p) 4585 { 4586 int port; 4587 4588 if (strcmp(p, "*") == 0) 4589 return FWD_PERMIT_ANY_PORT; 4590 if ((port = a2port(p)) > 0) 4591 return port; 4592 return -1; 4593 } 4594 4595 /* Try to start non-blocking connect to next host in cctx list */ 4596 static int 4597 connect_next(struct channel_connect *cctx) 4598 { 4599 int sock, saved_errno; 4600 struct sockaddr_un *sunaddr; 4601 char ntop[NI_MAXHOST]; 4602 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4603 4604 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4605 switch (cctx->ai->ai_family) { 4606 case AF_UNIX: 4607 /* unix:pathname instead of host:port */ 4608 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4609 strlcpy(ntop, "unix", sizeof(ntop)); 4610 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4611 break; 4612 case AF_INET: 4613 case AF_INET6: 4614 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4615 ntop, sizeof(ntop), strport, sizeof(strport), 4616 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4617 error_f("getnameinfo failed"); 4618 continue; 4619 } 4620 break; 4621 default: 4622 continue; 4623 } 4624 debug_f("start for host %.100s ([%.100s]:%s)", 4625 cctx->host, ntop, strport); 4626 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4627 cctx->ai->ai_protocol)) == -1) { 4628 if (cctx->ai->ai_next == NULL) 4629 error("socket: %.100s", strerror(errno)); 4630 else 4631 verbose("socket: %.100s", strerror(errno)); 4632 continue; 4633 } 4634 if (set_nonblock(sock) == -1) 4635 fatal_f("set_nonblock(%d)", sock); 4636 if (connect(sock, cctx->ai->ai_addr, 4637 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4638 debug_f("host %.100s ([%.100s]:%s): %.100s", 4639 cctx->host, ntop, strport, strerror(errno)); 4640 saved_errno = errno; 4641 close(sock); 4642 errno = saved_errno; 4643 continue; /* fail -- try next */ 4644 } 4645 if (cctx->ai->ai_family != AF_UNIX) 4646 set_nodelay(sock); 4647 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4648 cctx->host, ntop, strport, sock); 4649 cctx->ai = cctx->ai->ai_next; 4650 return sock; 4651 } 4652 return -1; 4653 } 4654 4655 static void 4656 channel_connect_ctx_free(struct channel_connect *cctx) 4657 { 4658 free(cctx->host); 4659 if (cctx->aitop) { 4660 if (cctx->aitop->ai_family == AF_UNIX) 4661 free(cctx->aitop); 4662 else 4663 freeaddrinfo(cctx->aitop); 4664 } 4665 memset(cctx, 0, sizeof(*cctx)); 4666 } 4667 4668 /* 4669 * Return connecting socket to remote host:port or local socket path, 4670 * passing back the failure reason if appropriate. 4671 */ 4672 static int 4673 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4674 char *ctype, char *rname, struct channel_connect *cctx, 4675 int *reason, const char **errmsg) 4676 { 4677 struct addrinfo hints; 4678 int gaierr; 4679 int sock = -1; 4680 char strport[NI_MAXSERV]; 4681 4682 if (port == PORT_STREAMLOCAL) { 4683 struct sockaddr_un *sunaddr; 4684 struct addrinfo *ai; 4685 4686 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4687 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4688 return -1; 4689 } 4690 4691 /* 4692 * Fake up a struct addrinfo for AF_UNIX connections. 4693 * channel_connect_ctx_free() must check ai_family 4694 * and use free() not freeaddirinfo() for AF_UNIX. 4695 */ 4696 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4697 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4698 ai->ai_addr = (struct sockaddr *)(ai + 1); 4699 ai->ai_addrlen = sizeof(*sunaddr); 4700 ai->ai_family = AF_UNIX; 4701 ai->ai_socktype = socktype; 4702 ai->ai_protocol = PF_UNSPEC; 4703 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4704 sunaddr->sun_family = AF_UNIX; 4705 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4706 cctx->aitop = ai; 4707 } else { 4708 memset(&hints, 0, sizeof(hints)); 4709 hints.ai_family = ssh->chanctxt->IPv4or6; 4710 hints.ai_socktype = socktype; 4711 snprintf(strport, sizeof strport, "%d", port); 4712 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4713 != 0) { 4714 if (errmsg != NULL) 4715 *errmsg = ssh_gai_strerror(gaierr); 4716 if (reason != NULL) 4717 *reason = SSH2_OPEN_CONNECT_FAILED; 4718 error("connect_to %.100s: unknown host (%s)", name, 4719 ssh_gai_strerror(gaierr)); 4720 return -1; 4721 } 4722 } 4723 4724 cctx->host = xstrdup(name); 4725 cctx->port = port; 4726 cctx->ai = cctx->aitop; 4727 4728 if ((sock = connect_next(cctx)) == -1) { 4729 error("connect to %.100s port %d failed: %s", 4730 name, port, strerror(errno)); 4731 return -1; 4732 } 4733 4734 return sock; 4735 } 4736 4737 /* Return CONNECTING channel to remote host:port or local socket path */ 4738 static Channel * 4739 connect_to(struct ssh *ssh, const char *host, int port, 4740 char *ctype, char *rname) 4741 { 4742 struct channel_connect cctx; 4743 Channel *c; 4744 int sock; 4745 4746 memset(&cctx, 0, sizeof(cctx)); 4747 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4748 &cctx, NULL, NULL); 4749 if (sock == -1) { 4750 channel_connect_ctx_free(&cctx); 4751 return NULL; 4752 } 4753 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4754 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4755 c->host_port = port; 4756 c->path = xstrdup(host); 4757 c->connect_ctx = cctx; 4758 4759 return c; 4760 } 4761 4762 /* 4763 * returns either the newly connected channel or the downstream channel 4764 * that needs to deal with this connection. 4765 */ 4766 Channel * 4767 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4768 u_short listen_port, char *ctype, char *rname) 4769 { 4770 struct ssh_channels *sc = ssh->chanctxt; 4771 struct permission_set *pset = &sc->local_perms; 4772 u_int i; 4773 struct permission *perm; 4774 4775 for (i = 0; i < pset->num_permitted_user; i++) { 4776 perm = &pset->permitted_user[i]; 4777 if (open_listen_match_tcpip(perm, 4778 listen_host, listen_port, 1)) { 4779 if (perm->downstream) 4780 return perm->downstream; 4781 if (perm->port_to_connect == 0) 4782 return rdynamic_connect_prepare(ssh, 4783 ctype, rname); 4784 return connect_to(ssh, 4785 perm->host_to_connect, perm->port_to_connect, 4786 ctype, rname); 4787 } 4788 } 4789 error("WARNING: Server requests forwarding for unknown listen_port %d", 4790 listen_port); 4791 return NULL; 4792 } 4793 4794 Channel * 4795 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4796 char *ctype, char *rname) 4797 { 4798 struct ssh_channels *sc = ssh->chanctxt; 4799 struct permission_set *pset = &sc->local_perms; 4800 u_int i; 4801 struct permission *perm; 4802 4803 for (i = 0; i < pset->num_permitted_user; i++) { 4804 perm = &pset->permitted_user[i]; 4805 if (open_listen_match_streamlocal(perm, path)) { 4806 return connect_to(ssh, 4807 perm->host_to_connect, perm->port_to_connect, 4808 ctype, rname); 4809 } 4810 } 4811 error("WARNING: Server requests forwarding for unknown path %.100s", 4812 path); 4813 return NULL; 4814 } 4815 4816 /* Check if connecting to that port is permitted and connect. */ 4817 Channel * 4818 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4819 char *ctype, char *rname, int *reason, const char **errmsg) 4820 { 4821 struct ssh_channels *sc = ssh->chanctxt; 4822 struct permission_set *pset = &sc->local_perms; 4823 struct channel_connect cctx; 4824 Channel *c; 4825 u_int i, permit, permit_adm = 1; 4826 int sock; 4827 struct permission *perm; 4828 4829 permit = pset->all_permitted; 4830 if (!permit) { 4831 for (i = 0; i < pset->num_permitted_user; i++) { 4832 perm = &pset->permitted_user[i]; 4833 if (open_match(perm, host, port)) { 4834 permit = 1; 4835 break; 4836 } 4837 } 4838 } 4839 4840 if (pset->num_permitted_admin > 0) { 4841 permit_adm = 0; 4842 for (i = 0; i < pset->num_permitted_admin; i++) { 4843 perm = &pset->permitted_admin[i]; 4844 if (open_match(perm, host, port)) { 4845 permit_adm = 1; 4846 break; 4847 } 4848 } 4849 } 4850 4851 if (!permit || !permit_adm) { 4852 logit("Received request from %.100s port %d to connect to " 4853 "host %.100s port %d, but the request was denied.", 4854 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4855 if (reason != NULL) 4856 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4857 return NULL; 4858 } 4859 4860 memset(&cctx, 0, sizeof(cctx)); 4861 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4862 &cctx, reason, errmsg); 4863 if (sock == -1) { 4864 channel_connect_ctx_free(&cctx); 4865 return NULL; 4866 } 4867 4868 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4869 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4870 c->host_port = port; 4871 c->path = xstrdup(host); 4872 c->connect_ctx = cctx; 4873 4874 return c; 4875 } 4876 4877 /* Check if connecting to that path is permitted and connect. */ 4878 Channel * 4879 channel_connect_to_path(struct ssh *ssh, const char *path, 4880 char *ctype, char *rname) 4881 { 4882 struct ssh_channels *sc = ssh->chanctxt; 4883 struct permission_set *pset = &sc->local_perms; 4884 u_int i, permit, permit_adm = 1; 4885 struct permission *perm; 4886 4887 permit = pset->all_permitted; 4888 if (!permit) { 4889 for (i = 0; i < pset->num_permitted_user; i++) { 4890 perm = &pset->permitted_user[i]; 4891 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4892 permit = 1; 4893 break; 4894 } 4895 } 4896 } 4897 4898 if (pset->num_permitted_admin > 0) { 4899 permit_adm = 0; 4900 for (i = 0; i < pset->num_permitted_admin; i++) { 4901 perm = &pset->permitted_admin[i]; 4902 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4903 permit_adm = 1; 4904 break; 4905 } 4906 } 4907 } 4908 4909 if (!permit || !permit_adm) { 4910 logit("Received request to connect to path %.100s, " 4911 "but the request was denied.", path); 4912 return NULL; 4913 } 4914 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4915 } 4916 4917 void 4918 channel_send_window_changes(struct ssh *ssh) 4919 { 4920 struct ssh_channels *sc = ssh->chanctxt; 4921 struct winsize ws; 4922 int r; 4923 u_int i; 4924 4925 for (i = 0; i < sc->channels_alloc; i++) { 4926 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4927 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4928 continue; 4929 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4930 continue; 4931 channel_request_start(ssh, i, "window-change", 0); 4932 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4933 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4934 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4935 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4936 (r = sshpkt_send(ssh)) != 0) 4937 fatal_fr(r, "channel %u; send window-change", i); 4938 } 4939 } 4940 4941 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4942 static Channel * 4943 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4944 { 4945 Channel *c; 4946 int r; 4947 4948 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4949 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4950 c->host_port = 0; 4951 c->path = NULL; 4952 4953 /* 4954 * We need to open the channel before we have a FD, 4955 * so that we can get SOCKS header from peer. 4956 */ 4957 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4958 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4959 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4960 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4961 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4962 fatal_fr(r, "channel %i; confirm", c->self); 4963 return c; 4964 } 4965 4966 /* Return CONNECTING socket to remote host:port or local socket path */ 4967 static int 4968 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4969 { 4970 struct ssh_channels *sc = ssh->chanctxt; 4971 struct permission_set *pset = &sc->local_perms; 4972 struct permission *perm; 4973 struct channel_connect cctx; 4974 u_int i, permit_adm = 1; 4975 int sock; 4976 4977 if (pset->num_permitted_admin > 0) { 4978 permit_adm = 0; 4979 for (i = 0; i < pset->num_permitted_admin; i++) { 4980 perm = &pset->permitted_admin[i]; 4981 if (open_match(perm, c->path, c->host_port)) { 4982 permit_adm = 1; 4983 break; 4984 } 4985 } 4986 } 4987 if (!permit_adm) { 4988 debug_f("requested forward not permitted"); 4989 return -1; 4990 } 4991 4992 memset(&cctx, 0, sizeof(cctx)); 4993 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4994 NULL, &cctx, NULL, NULL); 4995 if (sock == -1) 4996 channel_connect_ctx_free(&cctx); 4997 else { 4998 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4999 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 5000 c->connect_ctx = cctx; 5001 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 5002 } 5003 return sock; 5004 } 5005 5006 /* -- X11 forwarding */ 5007 5008 /* 5009 * Creates an internet domain socket for listening for X11 connections. 5010 * Returns 0 and a suitable display number for the DISPLAY variable 5011 * stored in display_numberp , or -1 if an error occurs. 5012 */ 5013 int 5014 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 5015 int x11_use_localhost, int single_connection, 5016 u_int *display_numberp, int **chanids) 5017 { 5018 Channel *nc = NULL; 5019 int display_number, sock; 5020 u_short port; 5021 struct addrinfo hints, *ai, *aitop; 5022 char strport[NI_MAXSERV]; 5023 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 5024 5025 if (chanids == NULL) 5026 return -1; 5027 5028 for (display_number = x11_display_offset; 5029 display_number < MAX_DISPLAYS; 5030 display_number++) { 5031 port = 6000 + display_number; 5032 memset(&hints, 0, sizeof(hints)); 5033 hints.ai_family = ssh->chanctxt->IPv4or6; 5034 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 5035 hints.ai_socktype = SOCK_STREAM; 5036 snprintf(strport, sizeof strport, "%d", port); 5037 if ((gaierr = getaddrinfo(NULL, strport, 5038 &hints, &aitop)) != 0) { 5039 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 5040 return -1; 5041 } 5042 for (ai = aitop; ai; ai = ai->ai_next) { 5043 if (ai->ai_family != AF_INET && 5044 ai->ai_family != AF_INET6) 5045 continue; 5046 sock = socket(ai->ai_family, ai->ai_socktype, 5047 ai->ai_protocol); 5048 if (sock == -1) { 5049 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 5050 #ifdef EPFNOSUPPORT 5051 && (errno != EPFNOSUPPORT) 5052 #endif 5053 ) { 5054 error("socket: %.100s", strerror(errno)); 5055 freeaddrinfo(aitop); 5056 return -1; 5057 } else { 5058 debug("x11_create_display_inet: Socket family %d not supported", 5059 ai->ai_family); 5060 continue; 5061 } 5062 } 5063 if (ai->ai_family == AF_INET6) 5064 sock_set_v6only(sock); 5065 if (x11_use_localhost) 5066 set_reuseaddr(sock); 5067 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5068 debug2_f("bind port %d: %.100s", port, 5069 strerror(errno)); 5070 close(sock); 5071 for (n = 0; n < num_socks; n++) 5072 close(socks[n]); 5073 num_socks = 0; 5074 break; 5075 } 5076 socks[num_socks++] = sock; 5077 if (num_socks == NUM_SOCKS) 5078 break; 5079 } 5080 freeaddrinfo(aitop); 5081 if (num_socks > 0) 5082 break; 5083 } 5084 if (display_number >= MAX_DISPLAYS) { 5085 error("Failed to allocate internet-domain X11 display socket."); 5086 return -1; 5087 } 5088 /* Start listening for connections on the socket. */ 5089 for (n = 0; n < num_socks; n++) { 5090 sock = socks[n]; 5091 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5092 error("listen: %.100s", strerror(errno)); 5093 close(sock); 5094 return -1; 5095 } 5096 } 5097 5098 /* Allocate a channel for each socket. */ 5099 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5100 for (n = 0; n < num_socks; n++) { 5101 sock = socks[n]; 5102 nc = channel_new(ssh, "x11-listener", 5103 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5104 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5105 0, "X11 inet listener", 1); 5106 nc->single_connection = single_connection; 5107 (*chanids)[n] = nc->self; 5108 } 5109 (*chanids)[n] = -1; 5110 5111 /* Return the display number for the DISPLAY environment variable. */ 5112 *display_numberp = display_number; 5113 return 0; 5114 } 5115 5116 static int 5117 connect_local_xsocket_path(const char *pathname) 5118 { 5119 int sock; 5120 struct sockaddr_un addr; 5121 5122 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5123 if (sock == -1) { 5124 error("socket: %.100s", strerror(errno)); 5125 return -1; 5126 } 5127 memset(&addr, 0, sizeof(addr)); 5128 addr.sun_family = AF_UNIX; 5129 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 5130 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5131 return sock; 5132 close(sock); 5133 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5134 return -1; 5135 } 5136 5137 static int 5138 connect_local_xsocket(u_int dnr) 5139 { 5140 char buf[1024]; 5141 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 5142 return connect_local_xsocket_path(buf); 5143 } 5144 5145 #ifdef __APPLE__ 5146 static int 5147 is_path_to_xsocket(const char *display, char *path, size_t pathlen) 5148 { 5149 struct stat sbuf; 5150 5151 if (strlcpy(path, display, pathlen) >= pathlen) { 5152 error("%s: display path too long", __func__); 5153 return 0; 5154 } 5155 if (display[0] != '/') 5156 return 0; 5157 if (stat(path, &sbuf) == 0) { 5158 return 1; 5159 } else { 5160 char *dot = strrchr(path, '.'); 5161 if (dot != NULL) { 5162 *dot = '\0'; 5163 if (stat(path, &sbuf) == 0) { 5164 return 1; 5165 } 5166 } 5167 } 5168 return 0; 5169 } 5170 #endif 5171 5172 int 5173 x11_connect_display(struct ssh *ssh) 5174 { 5175 u_int display_number; 5176 const char *display; 5177 char buf[1024], *cp; 5178 struct addrinfo hints, *ai, *aitop; 5179 char strport[NI_MAXSERV]; 5180 int gaierr, sock = 0; 5181 5182 /* Try to open a socket for the local X server. */ 5183 display = getenv("DISPLAY"); 5184 if (!display) { 5185 error("DISPLAY not set."); 5186 return -1; 5187 } 5188 /* 5189 * Now we decode the value of the DISPLAY variable and make a 5190 * connection to the real X server. 5191 */ 5192 5193 #ifdef __APPLE__ 5194 /* Check if display is a path to a socket (as set by launchd). */ 5195 { 5196 char path[PATH_MAX]; 5197 5198 if (is_path_to_xsocket(display, path, sizeof(path))) { 5199 debug("x11_connect_display: $DISPLAY is launchd"); 5200 5201 /* Create a socket. */ 5202 sock = connect_local_xsocket_path(path); 5203 if (sock < 0) 5204 return -1; 5205 5206 /* OK, we now have a connection to the display. */ 5207 return sock; 5208 } 5209 } 5210 #endif 5211 /* 5212 * Check if it is a unix domain socket. Unix domain displays are in 5213 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5214 */ 5215 if (strncmp(display, "unix:", 5) == 0 || 5216 display[0] == ':') { 5217 /* Connect to the unix domain socket. */ 5218 if (sscanf(strrchr(display, ':') + 1, "%u", 5219 &display_number) != 1) { 5220 error("Could not parse display number from DISPLAY: " 5221 "%.100s", display); 5222 return -1; 5223 } 5224 /* Create a socket. */ 5225 sock = connect_local_xsocket(display_number); 5226 if (sock < 0) 5227 return -1; 5228 5229 /* OK, we now have a connection to the display. */ 5230 return sock; 5231 } 5232 /* 5233 * Connect to an inet socket. The DISPLAY value is supposedly 5234 * hostname:d[.s], where hostname may also be numeric IP address. 5235 */ 5236 strlcpy(buf, display, sizeof(buf)); 5237 cp = strchr(buf, ':'); 5238 if (!cp) { 5239 error("Could not find ':' in DISPLAY: %.100s", display); 5240 return -1; 5241 } 5242 *cp = 0; 5243 /* 5244 * buf now contains the host name. But first we parse the 5245 * display number. 5246 */ 5247 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5248 error("Could not parse display number from DISPLAY: %.100s", 5249 display); 5250 return -1; 5251 } 5252 5253 /* Look up the host address */ 5254 memset(&hints, 0, sizeof(hints)); 5255 hints.ai_family = ssh->chanctxt->IPv4or6; 5256 hints.ai_socktype = SOCK_STREAM; 5257 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5258 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5259 error("%.100s: unknown host. (%s)", buf, 5260 ssh_gai_strerror(gaierr)); 5261 return -1; 5262 } 5263 for (ai = aitop; ai; ai = ai->ai_next) { 5264 /* Create a socket. */ 5265 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5266 if (sock == -1) { 5267 debug2("socket: %.100s", strerror(errno)); 5268 continue; 5269 } 5270 /* Connect it to the display. */ 5271 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5272 debug2("connect %.100s port %u: %.100s", buf, 5273 6000 + display_number, strerror(errno)); 5274 close(sock); 5275 continue; 5276 } 5277 /* Success */ 5278 break; 5279 } 5280 freeaddrinfo(aitop); 5281 if (!ai) { 5282 error("connect %.100s port %u: %.100s", buf, 5283 6000 + display_number, strerror(errno)); 5284 return -1; 5285 } 5286 set_nodelay(sock); 5287 return sock; 5288 } 5289 5290 /* 5291 * Requests forwarding of X11 connections, generates fake authentication 5292 * data, and enables authentication spoofing. 5293 * This should be called in the client only. 5294 */ 5295 void 5296 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5297 const char *disp, const char *proto, const char *data, int want_reply) 5298 { 5299 struct ssh_channels *sc = ssh->chanctxt; 5300 u_int data_len = (u_int) strlen(data) / 2; 5301 u_int i, value; 5302 const char *cp; 5303 char *new_data; 5304 int r, screen_number; 5305 5306 if (sc->x11_saved_display == NULL) 5307 sc->x11_saved_display = xstrdup(disp); 5308 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5309 error("x11_request_forwarding_with_spoofing: different " 5310 "$DISPLAY already forwarded"); 5311 return; 5312 } 5313 5314 cp = strchr(disp, ':'); 5315 if (cp) 5316 cp = strchr(cp, '.'); 5317 if (cp) 5318 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5319 else 5320 screen_number = 0; 5321 5322 if (sc->x11_saved_proto == NULL) { 5323 /* Save protocol name. */ 5324 sc->x11_saved_proto = xstrdup(proto); 5325 5326 /* Extract real authentication data. */ 5327 sc->x11_saved_data = xmalloc(data_len); 5328 for (i = 0; i < data_len; i++) { 5329 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5330 fatal("x11_request_forwarding: bad " 5331 "authentication data: %.100s", data); 5332 } 5333 sc->x11_saved_data[i] = value; 5334 } 5335 sc->x11_saved_data_len = data_len; 5336 5337 /* Generate fake data of the same length. */ 5338 sc->x11_fake_data = xmalloc(data_len); 5339 arc4random_buf(sc->x11_fake_data, data_len); 5340 sc->x11_fake_data_len = data_len; 5341 } 5342 5343 /* Convert the fake data into hex. */ 5344 new_data = tohex(sc->x11_fake_data, data_len); 5345 5346 /* Send the request packet. */ 5347 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5348 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5349 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5350 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5351 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5352 (r = sshpkt_send(ssh)) != 0 || 5353 (r = ssh_packet_write_wait(ssh)) != 0) 5354 fatal_fr(r, "send x11-req"); 5355 free(new_data); 5356 } 5357