1 /* $OpenBSD: channels.c,v 1.438 2024/05/17 00:30:23 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 /* -- X11 forwarding */ 97 /* Maximum number of fake X11 displays to try. */ 98 #define MAX_DISPLAYS 1000 99 100 /* Per-channel callback for pre/post IO actions */ 101 typedef void chan_fn(struct ssh *, Channel *c); 102 103 /* 104 * Data structure for storing which hosts are permitted for forward requests. 105 * The local sides of any remote forwards are stored in this array to prevent 106 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 107 * network (which might be behind a firewall). 108 */ 109 /* XXX: streamlocal wants a path instead of host:port */ 110 /* Overload host_to_connect; we could just make this match Forward */ 111 /* XXX - can we use listen_host instead of listen_path? */ 112 struct permission { 113 char *host_to_connect; /* Connect to 'host'. */ 114 int port_to_connect; /* Connect to 'port'. */ 115 char *listen_host; /* Remote side should listen address. */ 116 char *listen_path; /* Remote side should listen path. */ 117 int listen_port; /* Remote side should listen port. */ 118 Channel *downstream; /* Downstream mux*/ 119 }; 120 121 /* 122 * Stores the forwarding permission state for a single direction (local or 123 * remote). 124 */ 125 struct permission_set { 126 /* 127 * List of all local permitted host/port pairs to allow for the 128 * user. 129 */ 130 u_int num_permitted_user; 131 struct permission *permitted_user; 132 133 /* 134 * List of all permitted host/port pairs to allow for the admin. 135 */ 136 u_int num_permitted_admin; 137 struct permission *permitted_admin; 138 139 /* 140 * If this is true, all opens/listens are permitted. This is the 141 * case on the server on which we have to trust the client anyway, 142 * and the user could do anything after logging in. 143 */ 144 int all_permitted; 145 }; 146 147 /* Used to record timeouts per channel type */ 148 struct ssh_channel_timeout { 149 char *type_pattern; 150 int timeout_secs; 151 }; 152 153 /* Master structure for channels state */ 154 struct ssh_channels { 155 /* 156 * Pointer to an array containing all allocated channels. The array 157 * is dynamically extended as needed. 158 */ 159 Channel **channels; 160 161 /* 162 * Size of the channel array. All slots of the array must always be 163 * initialized (at least the type field); unused slots set to NULL 164 */ 165 u_int channels_alloc; 166 167 /* 168 * 'channel_pre*' are called just before IO to add any bits 169 * relevant to channels in the c->io_want bitmasks. 170 * 171 * 'channel_post*': perform any appropriate operations for 172 * channels which have c->io_ready events pending. 173 */ 174 chan_fn **channel_pre; 175 chan_fn **channel_post; 176 177 /* -- tcp forwarding */ 178 struct permission_set local_perms; 179 struct permission_set remote_perms; 180 181 /* -- X11 forwarding */ 182 183 /* Saved X11 local (client) display. */ 184 char *x11_saved_display; 185 186 /* Saved X11 authentication protocol name. */ 187 char *x11_saved_proto; 188 189 /* Saved X11 authentication data. This is the real data. */ 190 char *x11_saved_data; 191 u_int x11_saved_data_len; 192 193 /* Deadline after which all X11 connections are refused */ 194 time_t x11_refuse_time; 195 196 /* 197 * Fake X11 authentication data. This is what the server will be 198 * sending us; we should replace any occurrences of this by the 199 * real data. 200 */ 201 u_char *x11_fake_data; 202 u_int x11_fake_data_len; 203 204 /* AF_UNSPEC or AF_INET or AF_INET6 */ 205 int IPv4or6; 206 207 /* Channel timeouts by type */ 208 struct ssh_channel_timeout *timeouts; 209 size_t ntimeouts; 210 /* Global timeout for all OPEN channels */ 211 int global_deadline; 212 time_t lastused; 213 }; 214 215 /* helper */ 216 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 217 static const char *channel_rfwd_bind_host(const char *listen_host); 218 219 /* non-blocking connect helpers */ 220 static int connect_next(struct channel_connect *); 221 static void channel_connect_ctx_free(struct channel_connect *); 222 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 223 static int rdynamic_connect_finish(struct ssh *, Channel *); 224 225 /* Setup helper */ 226 static void channel_handler_init(struct ssh_channels *sc); 227 228 /* -- channel core */ 229 230 void 231 channel_init_channels(struct ssh *ssh) 232 { 233 struct ssh_channels *sc; 234 235 if ((sc = calloc(1, sizeof(*sc))) == NULL) 236 fatal_f("allocation failed"); 237 sc->channels_alloc = 10; 238 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 239 sc->IPv4or6 = AF_UNSPEC; 240 channel_handler_init(sc); 241 242 ssh->chanctxt = sc; 243 } 244 245 Channel * 246 channel_by_id(struct ssh *ssh, int id) 247 { 248 Channel *c; 249 250 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 251 logit_f("%d: bad id", id); 252 return NULL; 253 } 254 c = ssh->chanctxt->channels[id]; 255 if (c == NULL) { 256 logit_f("%d: bad id: channel free", id); 257 return NULL; 258 } 259 return c; 260 } 261 262 Channel * 263 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 264 { 265 Channel *c; 266 u_int i; 267 268 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 269 c = ssh->chanctxt->channels[i]; 270 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 271 return c; 272 } 273 return NULL; 274 } 275 276 /* 277 * Returns the channel if it is allowed to receive protocol messages. 278 * Private channels, like listening sockets, may not receive messages. 279 */ 280 Channel * 281 channel_lookup(struct ssh *ssh, int id) 282 { 283 Channel *c; 284 285 if ((c = channel_by_id(ssh, id)) == NULL) 286 return NULL; 287 288 switch (c->type) { 289 case SSH_CHANNEL_X11_OPEN: 290 case SSH_CHANNEL_LARVAL: 291 case SSH_CHANNEL_CONNECTING: 292 case SSH_CHANNEL_DYNAMIC: 293 case SSH_CHANNEL_RDYNAMIC_OPEN: 294 case SSH_CHANNEL_RDYNAMIC_FINISH: 295 case SSH_CHANNEL_OPENING: 296 case SSH_CHANNEL_OPEN: 297 case SSH_CHANNEL_ABANDONED: 298 case SSH_CHANNEL_MUX_PROXY: 299 return c; 300 } 301 logit("Non-public channel %d, type %d.", id, c->type); 302 return NULL; 303 } 304 305 /* 306 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 307 * match type_pattern. 308 */ 309 void 310 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 311 int timeout_secs) 312 { 313 struct ssh_channels *sc = ssh->chanctxt; 314 315 if (strcmp(type_pattern, "global") == 0) { 316 debug2_f("global channel timeout %d seconds", timeout_secs); 317 sc->global_deadline = timeout_secs; 318 return; 319 } 320 debug2_f("channel type \"%s\" timeout %d seconds", 321 type_pattern, timeout_secs); 322 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 323 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 324 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 325 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 326 sc->ntimeouts++; 327 } 328 329 /* Clears all previously-added channel timeouts */ 330 void 331 channel_clear_timeouts(struct ssh *ssh) 332 { 333 struct ssh_channels *sc = ssh->chanctxt; 334 size_t i; 335 336 debug3_f("clearing"); 337 for (i = 0; i < sc->ntimeouts; i++) 338 free(sc->timeouts[i].type_pattern); 339 free(sc->timeouts); 340 sc->timeouts = NULL; 341 sc->ntimeouts = 0; 342 } 343 344 static int 345 lookup_timeout(struct ssh *ssh, const char *type) 346 { 347 struct ssh_channels *sc = ssh->chanctxt; 348 size_t i; 349 350 for (i = 0; i < sc->ntimeouts; i++) { 351 if (match_pattern(type, sc->timeouts[i].type_pattern)) 352 return sc->timeouts[i].timeout_secs; 353 } 354 355 return 0; 356 } 357 358 /* 359 * Sets "extended type" of a channel; used by session layer to add additional 360 * information about channel types (e.g. shell, login, subsystem) that can then 361 * be used to select timeouts. 362 * Will reset c->inactive_deadline as a side-effect. 363 */ 364 void 365 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 366 { 367 Channel *c; 368 369 if ((c = channel_by_id(ssh, id)) == NULL) 370 fatal_f("missing channel %d", id); 371 if (c->xctype != NULL) 372 free(c->xctype); 373 c->xctype = xstrdup(xctype); 374 /* Type has changed, so look up inactivity deadline again */ 375 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 376 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 377 c->inactive_deadline); 378 } 379 380 /* 381 * update "last used" time on a channel. 382 * NB. nothing else should update lastused except to clear it. 383 */ 384 static void 385 channel_set_used_time(struct ssh *ssh, Channel *c) 386 { 387 ssh->chanctxt->lastused = monotime(); 388 if (c != NULL) 389 c->lastused = ssh->chanctxt->lastused; 390 } 391 392 /* 393 * Get the time at which a channel is due to time out for inactivity. 394 * Returns 0 if the channel is not due to time out ever. 395 */ 396 static time_t 397 channel_get_expiry(struct ssh *ssh, Channel *c) 398 { 399 struct ssh_channels *sc = ssh->chanctxt; 400 time_t expiry = 0, channel_expiry; 401 402 if (sc->lastused != 0 && sc->global_deadline != 0) 403 expiry = sc->lastused + sc->global_deadline; 404 if (c->lastused != 0 && c->inactive_deadline != 0) { 405 channel_expiry = c->lastused + c->inactive_deadline; 406 if (expiry == 0 || channel_expiry < expiry) 407 expiry = channel_expiry; 408 } 409 return expiry; 410 } 411 412 /* 413 * Register filedescriptors for a channel, used when allocating a channel or 414 * when the channel consumer/producer is ready, e.g. shell exec'd 415 */ 416 static void 417 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 418 int extusage, int nonblock, int is_tty) 419 { 420 int val; 421 422 if (rfd != -1) 423 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 424 if (wfd != -1 && wfd != rfd) 425 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 426 if (efd != -1 && efd != rfd && efd != wfd) 427 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 428 429 c->rfd = rfd; 430 c->wfd = wfd; 431 c->sock = (rfd == wfd) ? rfd : -1; 432 c->efd = efd; 433 c->extended_usage = extusage; 434 435 if ((c->isatty = is_tty) != 0) 436 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 437 #ifdef _AIX 438 /* XXX: Later AIX versions can't push as much data to tty */ 439 c->wfd_isatty = is_tty || isatty(c->wfd); 440 #endif 441 442 /* enable nonblocking mode */ 443 c->restore_block = 0; 444 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 445 /* 446 * Special handling for stdio file descriptors: do not set 447 * non-blocking mode if they are TTYs. Otherwise prepare to 448 * restore their blocking state on exit to avoid interfering 449 * with other programs that follow. 450 */ 451 if (rfd != -1 && !isatty(rfd) && 452 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 453 c->restore_flags[0] = val; 454 c->restore_block |= CHANNEL_RESTORE_RFD; 455 set_nonblock(rfd); 456 } 457 if (wfd != -1 && !isatty(wfd) && 458 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 459 c->restore_flags[1] = val; 460 c->restore_block |= CHANNEL_RESTORE_WFD; 461 set_nonblock(wfd); 462 } 463 if (efd != -1 && !isatty(efd) && 464 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 465 c->restore_flags[2] = val; 466 c->restore_block |= CHANNEL_RESTORE_EFD; 467 set_nonblock(efd); 468 } 469 } else if (nonblock) { 470 if (rfd != -1) 471 set_nonblock(rfd); 472 if (wfd != -1) 473 set_nonblock(wfd); 474 if (efd != -1) 475 set_nonblock(efd); 476 } 477 /* channel might be entering a larval state, so reset global timeout */ 478 channel_set_used_time(ssh, NULL); 479 } 480 481 /* 482 * Allocate a new channel object and set its type and socket. 483 */ 484 Channel * 485 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 486 u_int window, u_int maxpack, int extusage, const char *remote_name, 487 int nonblock) 488 { 489 struct ssh_channels *sc = ssh->chanctxt; 490 u_int i, found = 0; 491 Channel *c; 492 int r; 493 494 /* Try to find a free slot where to put the new channel. */ 495 for (i = 0; i < sc->channels_alloc; i++) { 496 if (sc->channels[i] == NULL) { 497 /* Found a free slot. */ 498 found = i; 499 break; 500 } 501 } 502 if (i >= sc->channels_alloc) { 503 /* 504 * There are no free slots. Take last+1 slot and expand 505 * the array. 506 */ 507 found = sc->channels_alloc; 508 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 509 fatal_f("internal error: channels_alloc %d too big", 510 sc->channels_alloc); 511 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 512 sc->channels_alloc + 10, sizeof(*sc->channels)); 513 sc->channels_alloc += 10; 514 debug2("channel: expanding %d", sc->channels_alloc); 515 } 516 /* Initialize and return new channel. */ 517 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 518 if ((c->input = sshbuf_new()) == NULL || 519 (c->output = sshbuf_new()) == NULL || 520 (c->extended = sshbuf_new()) == NULL) 521 fatal_f("sshbuf_new failed"); 522 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 523 fatal_fr(r, "sshbuf_set_max_size"); 524 c->ostate = CHAN_OUTPUT_OPEN; 525 c->istate = CHAN_INPUT_OPEN; 526 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 527 c->self = found; 528 c->type = type; 529 c->ctype = ctype; 530 c->local_window = window; 531 c->local_window_max = window; 532 c->local_maxpacket = maxpack; 533 c->remote_name = xstrdup(remote_name); 534 c->ctl_chan = -1; 535 c->delayed = 1; /* prevent call to channel_post handler */ 536 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 537 TAILQ_INIT(&c->status_confirms); 538 debug("channel %d: new %s [%s] (inactive timeout: %u)", 539 found, c->ctype, remote_name, c->inactive_deadline); 540 return c; 541 } 542 543 int 544 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 545 { 546 int ret, fd = *fdp; 547 548 if (fd == -1) 549 return 0; 550 551 /* restore blocking */ 552 if (*fdp == c->rfd && 553 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 554 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 555 else if (*fdp == c->wfd && 556 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 557 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 558 else if (*fdp == c->efd && 559 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 560 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 561 562 if (*fdp == c->rfd) { 563 c->io_want &= ~SSH_CHAN_IO_RFD; 564 c->io_ready &= ~SSH_CHAN_IO_RFD; 565 c->rfd = -1; 566 c->pfds[0] = -1; 567 } 568 if (*fdp == c->wfd) { 569 c->io_want &= ~SSH_CHAN_IO_WFD; 570 c->io_ready &= ~SSH_CHAN_IO_WFD; 571 c->wfd = -1; 572 c->pfds[1] = -1; 573 } 574 if (*fdp == c->efd) { 575 c->io_want &= ~SSH_CHAN_IO_EFD; 576 c->io_ready &= ~SSH_CHAN_IO_EFD; 577 c->efd = -1; 578 c->pfds[2] = -1; 579 } 580 if (*fdp == c->sock) { 581 c->io_want &= ~SSH_CHAN_IO_SOCK; 582 c->io_ready &= ~SSH_CHAN_IO_SOCK; 583 c->sock = -1; 584 c->pfds[3] = -1; 585 } 586 587 ret = close(fd); 588 *fdp = -1; /* probably redundant */ 589 return ret; 590 } 591 592 /* Close all channel fd/socket. */ 593 static void 594 channel_close_fds(struct ssh *ssh, Channel *c) 595 { 596 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 597 598 channel_close_fd(ssh, c, &c->sock); 599 if (rfd != sock) 600 channel_close_fd(ssh, c, &c->rfd); 601 if (wfd != sock && wfd != rfd) 602 channel_close_fd(ssh, c, &c->wfd); 603 if (efd != sock && efd != rfd && efd != wfd) 604 channel_close_fd(ssh, c, &c->efd); 605 } 606 607 static void 608 fwd_perm_clear(struct permission *perm) 609 { 610 free(perm->host_to_connect); 611 free(perm->listen_host); 612 free(perm->listen_path); 613 memset(perm, 0, sizeof(*perm)); 614 } 615 616 /* Returns an printable name for the specified forwarding permission list */ 617 static const char * 618 fwd_ident(int who, int where) 619 { 620 if (who == FORWARD_ADM) { 621 if (where == FORWARD_LOCAL) 622 return "admin local"; 623 else if (where == FORWARD_REMOTE) 624 return "admin remote"; 625 } else if (who == FORWARD_USER) { 626 if (where == FORWARD_LOCAL) 627 return "user local"; 628 else if (where == FORWARD_REMOTE) 629 return "user remote"; 630 } 631 fatal("Unknown forward permission list %d/%d", who, where); 632 } 633 634 /* Returns the forwarding permission list for the specified direction */ 635 static struct permission_set * 636 permission_set_get(struct ssh *ssh, int where) 637 { 638 struct ssh_channels *sc = ssh->chanctxt; 639 640 switch (where) { 641 case FORWARD_LOCAL: 642 return &sc->local_perms; 643 break; 644 case FORWARD_REMOTE: 645 return &sc->remote_perms; 646 break; 647 default: 648 fatal_f("invalid forwarding direction %d", where); 649 } 650 } 651 652 /* Returns pointers to the specified forwarding list and its element count */ 653 static void 654 permission_set_get_array(struct ssh *ssh, int who, int where, 655 struct permission ***permpp, u_int **npermpp) 656 { 657 struct permission_set *pset = permission_set_get(ssh, where); 658 659 switch (who) { 660 case FORWARD_USER: 661 *permpp = &pset->permitted_user; 662 *npermpp = &pset->num_permitted_user; 663 break; 664 case FORWARD_ADM: 665 *permpp = &pset->permitted_admin; 666 *npermpp = &pset->num_permitted_admin; 667 break; 668 default: 669 fatal_f("invalid forwarding client %d", who); 670 } 671 } 672 673 /* Adds an entry to the specified forwarding list */ 674 static int 675 permission_set_add(struct ssh *ssh, int who, int where, 676 const char *host_to_connect, int port_to_connect, 677 const char *listen_host, const char *listen_path, int listen_port, 678 Channel *downstream) 679 { 680 struct permission **permp; 681 u_int n, *npermp; 682 683 permission_set_get_array(ssh, who, where, &permp, &npermp); 684 685 if (*npermp >= INT_MAX) 686 fatal_f("%s overflow", fwd_ident(who, where)); 687 688 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 689 n = (*npermp)++; 690 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 691 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 692 (*permp)[n].port_to_connect = port_to_connect; 693 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 694 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 695 (*permp)[n].listen_port = listen_port; 696 (*permp)[n].downstream = downstream; 697 #undef MAYBE_DUP 698 return (int)n; 699 } 700 701 static void 702 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 703 { 704 struct ssh_channels *sc = ssh->chanctxt; 705 struct permission_set *pset = &sc->local_perms; 706 struct permission *perm; 707 int r; 708 u_int i; 709 710 for (i = 0; i < pset->num_permitted_user; i++) { 711 perm = &pset->permitted_user[i]; 712 if (perm->downstream != c) 713 continue; 714 715 /* cancel on the server, since mux client is gone */ 716 debug("channel %d: cleanup remote forward for %s:%u", 717 c->self, perm->listen_host, perm->listen_port); 718 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 719 (r = sshpkt_put_cstring(ssh, 720 "cancel-tcpip-forward")) != 0 || 721 (r = sshpkt_put_u8(ssh, 0)) != 0 || 722 (r = sshpkt_put_cstring(ssh, 723 channel_rfwd_bind_host(perm->listen_host))) != 0 || 724 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 725 (r = sshpkt_send(ssh)) != 0) { 726 fatal_fr(r, "channel %i", c->self); 727 } 728 fwd_perm_clear(perm); /* unregister */ 729 } 730 } 731 732 /* Free the channel and close its fd/socket. */ 733 void 734 channel_free(struct ssh *ssh, Channel *c) 735 { 736 struct ssh_channels *sc = ssh->chanctxt; 737 char *s; 738 u_int i, n; 739 Channel *other; 740 struct channel_confirm *cc; 741 742 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 743 if ((other = sc->channels[i]) == NULL) 744 continue; 745 n++; 746 /* detach from mux client and prepare for closing */ 747 if (c->type == SSH_CHANNEL_MUX_CLIENT && 748 other->type == SSH_CHANNEL_MUX_PROXY && 749 other->mux_ctx == c) { 750 other->mux_ctx = NULL; 751 other->type = SSH_CHANNEL_OPEN; 752 other->istate = CHAN_INPUT_CLOSED; 753 other->ostate = CHAN_OUTPUT_CLOSED; 754 } 755 } 756 debug("channel %d: free: %s, nchannels %u", c->self, 757 c->remote_name ? c->remote_name : "???", n); 758 759 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 760 mux_remove_remote_forwardings(ssh, c); 761 free(c->mux_ctx); 762 c->mux_ctx = NULL; 763 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 764 free(c->mux_ctx); 765 c->mux_ctx = NULL; 766 } 767 768 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 769 s = channel_open_message(ssh); 770 debug3("channel %d: status: %s", c->self, s); 771 free(s); 772 } 773 774 channel_close_fds(ssh, c); 775 sshbuf_free(c->input); 776 sshbuf_free(c->output); 777 sshbuf_free(c->extended); 778 c->input = c->output = c->extended = NULL; 779 free(c->remote_name); 780 c->remote_name = NULL; 781 free(c->path); 782 c->path = NULL; 783 free(c->listening_addr); 784 c->listening_addr = NULL; 785 free(c->xctype); 786 c->xctype = NULL; 787 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 788 if (cc->abandon_cb != NULL) 789 cc->abandon_cb(ssh, c, cc->ctx); 790 TAILQ_REMOVE(&c->status_confirms, cc, entry); 791 freezero(cc, sizeof(*cc)); 792 } 793 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 794 c->filter_cleanup(ssh, c->self, c->filter_ctx); 795 sc->channels[c->self] = NULL; 796 freezero(c, sizeof(*c)); 797 } 798 799 void 800 channel_free_all(struct ssh *ssh) 801 { 802 u_int i; 803 struct ssh_channels *sc = ssh->chanctxt; 804 805 for (i = 0; i < sc->channels_alloc; i++) 806 if (sc->channels[i] != NULL) 807 channel_free(ssh, sc->channels[i]); 808 809 free(sc->channels); 810 sc->channels = NULL; 811 sc->channels_alloc = 0; 812 813 free(sc->x11_saved_display); 814 sc->x11_saved_display = NULL; 815 816 free(sc->x11_saved_proto); 817 sc->x11_saved_proto = NULL; 818 819 free(sc->x11_saved_data); 820 sc->x11_saved_data = NULL; 821 sc->x11_saved_data_len = 0; 822 823 free(sc->x11_fake_data); 824 sc->x11_fake_data = NULL; 825 sc->x11_fake_data_len = 0; 826 } 827 828 /* 829 * Closes the sockets/fds of all channels. This is used to close extra file 830 * descriptors after a fork. 831 */ 832 void 833 channel_close_all(struct ssh *ssh) 834 { 835 u_int i; 836 837 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 838 if (ssh->chanctxt->channels[i] != NULL) 839 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 840 } 841 842 /* 843 * Stop listening to channels. 844 */ 845 void 846 channel_stop_listening(struct ssh *ssh) 847 { 848 u_int i; 849 Channel *c; 850 851 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 852 c = ssh->chanctxt->channels[i]; 853 if (c != NULL) { 854 switch (c->type) { 855 case SSH_CHANNEL_AUTH_SOCKET: 856 case SSH_CHANNEL_PORT_LISTENER: 857 case SSH_CHANNEL_RPORT_LISTENER: 858 case SSH_CHANNEL_X11_LISTENER: 859 case SSH_CHANNEL_UNIX_LISTENER: 860 case SSH_CHANNEL_RUNIX_LISTENER: 861 channel_close_fd(ssh, c, &c->sock); 862 channel_free(ssh, c); 863 break; 864 } 865 } 866 } 867 } 868 869 /* 870 * Returns true if no channel has too much buffered data, and false if one or 871 * more channel is overfull. 872 */ 873 int 874 channel_not_very_much_buffered_data(struct ssh *ssh) 875 { 876 u_int i; 877 u_int maxsize = ssh_packet_get_maxsize(ssh); 878 Channel *c; 879 880 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 881 c = ssh->chanctxt->channels[i]; 882 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 883 continue; 884 if (sshbuf_len(c->output) > maxsize) { 885 debug2("channel %d: big output buffer %zu > %u", 886 c->self, sshbuf_len(c->output), maxsize); 887 return 0; 888 } 889 } 890 return 1; 891 } 892 893 /* Returns true if any channel is still open. */ 894 int 895 channel_still_open(struct ssh *ssh) 896 { 897 u_int i; 898 Channel *c; 899 900 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 901 c = ssh->chanctxt->channels[i]; 902 if (c == NULL) 903 continue; 904 switch (c->type) { 905 case SSH_CHANNEL_X11_LISTENER: 906 case SSH_CHANNEL_PORT_LISTENER: 907 case SSH_CHANNEL_RPORT_LISTENER: 908 case SSH_CHANNEL_MUX_LISTENER: 909 case SSH_CHANNEL_CLOSED: 910 case SSH_CHANNEL_AUTH_SOCKET: 911 case SSH_CHANNEL_DYNAMIC: 912 case SSH_CHANNEL_RDYNAMIC_OPEN: 913 case SSH_CHANNEL_CONNECTING: 914 case SSH_CHANNEL_ZOMBIE: 915 case SSH_CHANNEL_ABANDONED: 916 case SSH_CHANNEL_UNIX_LISTENER: 917 case SSH_CHANNEL_RUNIX_LISTENER: 918 continue; 919 case SSH_CHANNEL_LARVAL: 920 continue; 921 case SSH_CHANNEL_OPENING: 922 case SSH_CHANNEL_OPEN: 923 case SSH_CHANNEL_RDYNAMIC_FINISH: 924 case SSH_CHANNEL_X11_OPEN: 925 case SSH_CHANNEL_MUX_CLIENT: 926 case SSH_CHANNEL_MUX_PROXY: 927 return 1; 928 default: 929 fatal_f("bad channel type %d", c->type); 930 /* NOTREACHED */ 931 } 932 } 933 return 0; 934 } 935 936 /* Returns true if a channel with a TTY is open. */ 937 int 938 channel_tty_open(struct ssh *ssh) 939 { 940 u_int i; 941 Channel *c; 942 943 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 944 c = ssh->chanctxt->channels[i]; 945 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 946 continue; 947 if (c->client_tty) 948 return 1; 949 } 950 return 0; 951 } 952 953 /* Returns the id of an open channel suitable for keepaliving */ 954 int 955 channel_find_open(struct ssh *ssh) 956 { 957 u_int i; 958 Channel *c; 959 960 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 961 c = ssh->chanctxt->channels[i]; 962 if (c == NULL || !c->have_remote_id) 963 continue; 964 switch (c->type) { 965 case SSH_CHANNEL_CLOSED: 966 case SSH_CHANNEL_DYNAMIC: 967 case SSH_CHANNEL_RDYNAMIC_OPEN: 968 case SSH_CHANNEL_RDYNAMIC_FINISH: 969 case SSH_CHANNEL_X11_LISTENER: 970 case SSH_CHANNEL_PORT_LISTENER: 971 case SSH_CHANNEL_RPORT_LISTENER: 972 case SSH_CHANNEL_MUX_LISTENER: 973 case SSH_CHANNEL_MUX_CLIENT: 974 case SSH_CHANNEL_MUX_PROXY: 975 case SSH_CHANNEL_OPENING: 976 case SSH_CHANNEL_CONNECTING: 977 case SSH_CHANNEL_ZOMBIE: 978 case SSH_CHANNEL_ABANDONED: 979 case SSH_CHANNEL_UNIX_LISTENER: 980 case SSH_CHANNEL_RUNIX_LISTENER: 981 continue; 982 case SSH_CHANNEL_LARVAL: 983 case SSH_CHANNEL_AUTH_SOCKET: 984 case SSH_CHANNEL_OPEN: 985 case SSH_CHANNEL_X11_OPEN: 986 return i; 987 default: 988 fatal_f("bad channel type %d", c->type); 989 /* NOTREACHED */ 990 } 991 } 992 return -1; 993 } 994 995 /* Returns the state of the channel's extended usage flag */ 996 const char * 997 channel_format_extended_usage(const Channel *c) 998 { 999 if (c->efd == -1) 1000 return "closed"; 1001 1002 switch (c->extended_usage) { 1003 case CHAN_EXTENDED_WRITE: 1004 return "write"; 1005 case CHAN_EXTENDED_READ: 1006 return "read"; 1007 case CHAN_EXTENDED_IGNORE: 1008 return "ignore"; 1009 default: 1010 return "UNKNOWN"; 1011 } 1012 } 1013 1014 static char * 1015 channel_format_status(const Channel *c) 1016 { 1017 char *ret = NULL; 1018 1019 xasprintf(&ret, "t%d [%s] %s%u i%u/%zu o%u/%zu e[%s]/%zu " 1020 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 1021 c->type, c->xctype != NULL ? c->xctype : c->ctype, 1022 c->have_remote_id ? "r" : "nr", c->remote_id, 1023 c->istate, sshbuf_len(c->input), 1024 c->ostate, sshbuf_len(c->output), 1025 channel_format_extended_usage(c), sshbuf_len(c->extended), 1026 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 1027 c->io_want, c->io_ready); 1028 return ret; 1029 } 1030 1031 /* 1032 * Returns a message describing the currently open forwarded connections, 1033 * suitable for sending to the client. The message contains crlf pairs for 1034 * newlines. 1035 */ 1036 char * 1037 channel_open_message(struct ssh *ssh) 1038 { 1039 struct sshbuf *buf; 1040 Channel *c; 1041 u_int i; 1042 int r; 1043 char *cp, *ret; 1044 1045 if ((buf = sshbuf_new()) == NULL) 1046 fatal_f("sshbuf_new"); 1047 if ((r = sshbuf_putf(buf, 1048 "The following connections are open:\r\n")) != 0) 1049 fatal_fr(r, "sshbuf_putf"); 1050 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1051 c = ssh->chanctxt->channels[i]; 1052 if (c == NULL) 1053 continue; 1054 switch (c->type) { 1055 case SSH_CHANNEL_X11_LISTENER: 1056 case SSH_CHANNEL_PORT_LISTENER: 1057 case SSH_CHANNEL_RPORT_LISTENER: 1058 case SSH_CHANNEL_CLOSED: 1059 case SSH_CHANNEL_AUTH_SOCKET: 1060 case SSH_CHANNEL_ZOMBIE: 1061 case SSH_CHANNEL_ABANDONED: 1062 case SSH_CHANNEL_MUX_LISTENER: 1063 case SSH_CHANNEL_UNIX_LISTENER: 1064 case SSH_CHANNEL_RUNIX_LISTENER: 1065 continue; 1066 case SSH_CHANNEL_LARVAL: 1067 case SSH_CHANNEL_OPENING: 1068 case SSH_CHANNEL_CONNECTING: 1069 case SSH_CHANNEL_DYNAMIC: 1070 case SSH_CHANNEL_RDYNAMIC_OPEN: 1071 case SSH_CHANNEL_RDYNAMIC_FINISH: 1072 case SSH_CHANNEL_OPEN: 1073 case SSH_CHANNEL_X11_OPEN: 1074 case SSH_CHANNEL_MUX_PROXY: 1075 case SSH_CHANNEL_MUX_CLIENT: 1076 cp = channel_format_status(c); 1077 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1078 c->self, c->remote_name, cp)) != 0) { 1079 free(cp); 1080 fatal_fr(r, "sshbuf_putf"); 1081 } 1082 free(cp); 1083 continue; 1084 default: 1085 fatal_f("bad channel type %d", c->type); 1086 /* NOTREACHED */ 1087 } 1088 } 1089 if ((ret = sshbuf_dup_string(buf)) == NULL) 1090 fatal_f("sshbuf_dup_string"); 1091 sshbuf_free(buf); 1092 return ret; 1093 } 1094 1095 static void 1096 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1097 { 1098 int r; 1099 1100 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1101 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1102 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1103 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1104 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1105 fatal_r(r, "%s: channel %i: open", where, c->self); 1106 } 1107 } 1108 1109 void 1110 channel_send_open(struct ssh *ssh, int id) 1111 { 1112 Channel *c = channel_lookup(ssh, id); 1113 int r; 1114 1115 if (c == NULL) { 1116 logit("channel_send_open: %d: bad id", id); 1117 return; 1118 } 1119 debug2("channel %d: send open", id); 1120 open_preamble(ssh, __func__, c, c->ctype); 1121 if ((r = sshpkt_send(ssh)) != 0) 1122 fatal_fr(r, "channel %i", c->self); 1123 } 1124 1125 void 1126 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 1127 { 1128 Channel *c = channel_lookup(ssh, id); 1129 int r; 1130 1131 if (c == NULL) { 1132 logit_f("%d: unknown channel id", id); 1133 return; 1134 } 1135 if (!c->have_remote_id) 1136 fatal_f("channel %d: no remote id", c->self); 1137 1138 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1139 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1140 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1141 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1142 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1143 fatal_fr(r, "channel %i", c->self); 1144 } 1145 } 1146 1147 void 1148 channel_register_status_confirm(struct ssh *ssh, int id, 1149 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1150 { 1151 struct channel_confirm *cc; 1152 Channel *c; 1153 1154 if ((c = channel_lookup(ssh, id)) == NULL) 1155 fatal_f("%d: bad id", id); 1156 1157 cc = xcalloc(1, sizeof(*cc)); 1158 cc->cb = cb; 1159 cc->abandon_cb = abandon_cb; 1160 cc->ctx = ctx; 1161 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1162 } 1163 1164 void 1165 channel_register_open_confirm(struct ssh *ssh, int id, 1166 channel_open_fn *fn, void *ctx) 1167 { 1168 Channel *c = channel_lookup(ssh, id); 1169 1170 if (c == NULL) { 1171 logit_f("%d: bad id", id); 1172 return; 1173 } 1174 c->open_confirm = fn; 1175 c->open_confirm_ctx = ctx; 1176 } 1177 1178 void 1179 channel_register_cleanup(struct ssh *ssh, int id, 1180 channel_callback_fn *fn, int do_close) 1181 { 1182 Channel *c = channel_by_id(ssh, id); 1183 1184 if (c == NULL) { 1185 logit_f("%d: bad id", id); 1186 return; 1187 } 1188 c->detach_user = fn; 1189 c->detach_close = do_close; 1190 } 1191 1192 void 1193 channel_cancel_cleanup(struct ssh *ssh, int id) 1194 { 1195 Channel *c = channel_by_id(ssh, id); 1196 1197 if (c == NULL) { 1198 logit_f("%d: bad id", id); 1199 return; 1200 } 1201 c->detach_user = NULL; 1202 c->detach_close = 0; 1203 } 1204 1205 void 1206 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1207 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1208 { 1209 Channel *c = channel_lookup(ssh, id); 1210 1211 if (c == NULL) { 1212 logit_f("%d: bad id", id); 1213 return; 1214 } 1215 c->input_filter = ifn; 1216 c->output_filter = ofn; 1217 c->filter_ctx = ctx; 1218 c->filter_cleanup = cfn; 1219 } 1220 1221 void 1222 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1223 int extusage, int nonblock, int is_tty, u_int window_max) 1224 { 1225 Channel *c = channel_lookup(ssh, id); 1226 int r; 1227 1228 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1229 fatal("channel_activate for non-larval channel %d.", id); 1230 if (!c->have_remote_id) 1231 fatal_f("channel %d: no remote id", c->self); 1232 1233 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1234 c->type = SSH_CHANNEL_OPEN; 1235 channel_set_used_time(ssh, c); 1236 c->local_window = c->local_window_max = window_max; 1237 1238 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1239 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1240 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1241 (r = sshpkt_send(ssh)) != 0) 1242 fatal_fr(r, "channel %i", c->self); 1243 } 1244 1245 static void 1246 channel_pre_listener(struct ssh *ssh, Channel *c) 1247 { 1248 c->io_want = SSH_CHAN_IO_SOCK_R; 1249 } 1250 1251 static void 1252 channel_pre_connecting(struct ssh *ssh, Channel *c) 1253 { 1254 debug3("channel %d: waiting for connection", c->self); 1255 c->io_want = SSH_CHAN_IO_SOCK_W; 1256 } 1257 1258 static void 1259 channel_pre_open(struct ssh *ssh, Channel *c) 1260 { 1261 c->io_want = 0; 1262 if (c->istate == CHAN_INPUT_OPEN && 1263 c->remote_window > 0 && 1264 sshbuf_len(c->input) < c->remote_window && 1265 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1266 c->io_want |= SSH_CHAN_IO_RFD; 1267 if (c->ostate == CHAN_OUTPUT_OPEN || 1268 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1269 if (sshbuf_len(c->output) > 0) { 1270 c->io_want |= SSH_CHAN_IO_WFD; 1271 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1272 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1273 debug2("channel %d: " 1274 "obuf_empty delayed efd %d/(%zu)", c->self, 1275 c->efd, sshbuf_len(c->extended)); 1276 else 1277 chan_obuf_empty(ssh, c); 1278 } 1279 } 1280 /** XXX check close conditions, too */ 1281 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1282 c->ostate == CHAN_OUTPUT_CLOSED)) { 1283 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1284 sshbuf_len(c->extended) > 0) 1285 c->io_want |= SSH_CHAN_IO_EFD_W; 1286 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1287 (c->extended_usage == CHAN_EXTENDED_READ || 1288 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1289 sshbuf_len(c->extended) < c->remote_window) 1290 c->io_want |= SSH_CHAN_IO_EFD_R; 1291 } 1292 /* XXX: What about efd? races? */ 1293 } 1294 1295 /* 1296 * This is a special state for X11 authentication spoofing. An opened X11 1297 * connection (when authentication spoofing is being done) remains in this 1298 * state until the first packet has been completely read. The authentication 1299 * data in that packet is then substituted by the real data if it matches the 1300 * fake data, and the channel is put into normal mode. 1301 * XXX All this happens at the client side. 1302 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1303 */ 1304 static int 1305 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1306 { 1307 struct ssh_channels *sc = ssh->chanctxt; 1308 u_char *ucp; 1309 u_int proto_len, data_len; 1310 1311 /* Is this being called after the refusal deadline? */ 1312 if (sc->x11_refuse_time != 0 && 1313 monotime() >= sc->x11_refuse_time) { 1314 verbose("Rejected X11 connection after ForwardX11Timeout " 1315 "expired"); 1316 return -1; 1317 } 1318 1319 /* Check if the fixed size part of the packet is in buffer. */ 1320 if (sshbuf_len(b) < 12) 1321 return 0; 1322 1323 /* Parse the lengths of variable-length fields. */ 1324 ucp = sshbuf_mutable_ptr(b); 1325 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1326 proto_len = 256 * ucp[6] + ucp[7]; 1327 data_len = 256 * ucp[8] + ucp[9]; 1328 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1329 proto_len = ucp[6] + 256 * ucp[7]; 1330 data_len = ucp[8] + 256 * ucp[9]; 1331 } else { 1332 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1333 ucp[0]); 1334 return -1; 1335 } 1336 1337 /* Check if the whole packet is in buffer. */ 1338 if (sshbuf_len(b) < 1339 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1340 return 0; 1341 1342 /* Check if authentication protocol matches. */ 1343 if (proto_len != strlen(sc->x11_saved_proto) || 1344 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1345 debug2("X11 connection uses different authentication protocol."); 1346 return -1; 1347 } 1348 /* Check if authentication data matches our fake data. */ 1349 if (data_len != sc->x11_fake_data_len || 1350 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1351 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1352 debug2("X11 auth data does not match fake data."); 1353 return -1; 1354 } 1355 /* Check fake data length */ 1356 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1357 error("X11 fake_data_len %d != saved_data_len %d", 1358 sc->x11_fake_data_len, sc->x11_saved_data_len); 1359 return -1; 1360 } 1361 /* 1362 * Received authentication protocol and data match 1363 * our fake data. Substitute the fake data with real 1364 * data. 1365 */ 1366 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1367 sc->x11_saved_data, sc->x11_saved_data_len); 1368 return 1; 1369 } 1370 1371 void 1372 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1373 { 1374 debug3_f("channel %d: forcibly closing", c->self); 1375 if (c->istate == CHAN_INPUT_OPEN) 1376 chan_read_failed(ssh, c); 1377 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1378 sshbuf_reset(c->input); 1379 chan_ibuf_empty(ssh, c); 1380 } 1381 if (c->ostate == CHAN_OUTPUT_OPEN || 1382 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1383 sshbuf_reset(c->output); 1384 chan_write_failed(ssh, c); 1385 } 1386 if (c->detach_user) 1387 c->detach_user(ssh, c->self, 1, NULL); 1388 if (c->efd != -1) 1389 channel_close_fd(ssh, c, &c->efd); 1390 if (abandon) 1391 c->type = SSH_CHANNEL_ABANDONED; 1392 /* exempt from inactivity timeouts */ 1393 c->inactive_deadline = 0; 1394 c->lastused = 0; 1395 } 1396 1397 static void 1398 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1399 { 1400 int ret = x11_open_helper(ssh, c->output); 1401 1402 /* c->force_drain = 1; */ 1403 1404 if (ret == 1) { 1405 c->type = SSH_CHANNEL_OPEN; 1406 channel_set_used_time(ssh, c); 1407 channel_pre_open(ssh, c); 1408 } else if (ret == -1) { 1409 logit("X11 connection rejected because of wrong " 1410 "authentication."); 1411 debug2("X11 rejected %d i%d/o%d", 1412 c->self, c->istate, c->ostate); 1413 channel_force_close(ssh, c, 0); 1414 } 1415 } 1416 1417 static void 1418 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1419 { 1420 c->io_want = 0; 1421 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1422 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1423 c->io_want |= SSH_CHAN_IO_RFD; 1424 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1425 /* clear buffer immediately (discard any partial packet) */ 1426 sshbuf_reset(c->input); 1427 chan_ibuf_empty(ssh, c); 1428 /* Start output drain. XXX just kill chan? */ 1429 chan_rcvd_oclose(ssh, c); 1430 } 1431 if (c->ostate == CHAN_OUTPUT_OPEN || 1432 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1433 if (sshbuf_len(c->output) > 0) 1434 c->io_want |= SSH_CHAN_IO_WFD; 1435 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1436 chan_obuf_empty(ssh, c); 1437 } 1438 } 1439 1440 /* try to decode a socks4 header */ 1441 static int 1442 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1443 { 1444 const u_char *p; 1445 char *host; 1446 u_int len, have, i, found, need; 1447 char username[256]; 1448 struct { 1449 u_int8_t version; 1450 u_int8_t command; 1451 u_int16_t dest_port; 1452 struct in_addr dest_addr; 1453 } s4_req, s4_rsp; 1454 int r; 1455 1456 debug2("channel %d: decode socks4", c->self); 1457 1458 have = sshbuf_len(input); 1459 len = sizeof(s4_req); 1460 if (have < len) 1461 return 0; 1462 p = sshbuf_ptr(input); 1463 1464 need = 1; 1465 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1466 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1467 debug2("channel %d: socks4a request", c->self); 1468 /* ... and needs an extra string (the hostname) */ 1469 need = 2; 1470 } 1471 /* Check for terminating NUL on the string(s) */ 1472 for (found = 0, i = len; i < have; i++) { 1473 if (p[i] == '\0') { 1474 found++; 1475 if (found == need) 1476 break; 1477 } 1478 if (i > 1024) { 1479 /* the peer is probably sending garbage */ 1480 debug("channel %d: decode socks4: too long", 1481 c->self); 1482 return -1; 1483 } 1484 } 1485 if (found < need) 1486 return 0; 1487 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1488 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1489 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1490 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1491 debug_r(r, "channels %d: decode socks4", c->self); 1492 return -1; 1493 } 1494 have = sshbuf_len(input); 1495 p = sshbuf_ptr(input); 1496 if (memchr(p, '\0', have) == NULL) { 1497 error("channel %d: decode socks4: unterminated user", c->self); 1498 return -1; 1499 } 1500 len = strlen(p); 1501 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1502 len++; /* trailing '\0' */ 1503 strlcpy(username, p, sizeof(username)); 1504 if ((r = sshbuf_consume(input, len)) != 0) 1505 fatal_fr(r, "channel %d: consume", c->self); 1506 free(c->path); 1507 c->path = NULL; 1508 if (need == 1) { /* SOCKS4: one string */ 1509 host = inet_ntoa(s4_req.dest_addr); 1510 c->path = xstrdup(host); 1511 } else { /* SOCKS4A: two strings */ 1512 have = sshbuf_len(input); 1513 p = sshbuf_ptr(input); 1514 if (memchr(p, '\0', have) == NULL) { 1515 error("channel %d: decode socks4a: host not nul " 1516 "terminated", c->self); 1517 return -1; 1518 } 1519 len = strlen(p); 1520 debug2("channel %d: decode socks4a: host %s/%d", 1521 c->self, p, len); 1522 len++; /* trailing '\0' */ 1523 if (len > NI_MAXHOST) { 1524 error("channel %d: hostname \"%.100s\" too long", 1525 c->self, p); 1526 return -1; 1527 } 1528 c->path = xstrdup(p); 1529 if ((r = sshbuf_consume(input, len)) != 0) 1530 fatal_fr(r, "channel %d: consume", c->self); 1531 } 1532 c->host_port = ntohs(s4_req.dest_port); 1533 1534 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1535 c->self, c->path, c->host_port, s4_req.command); 1536 1537 if (s4_req.command != 1) { 1538 debug("channel %d: cannot handle: %s cn %d", 1539 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1540 return -1; 1541 } 1542 s4_rsp.version = 0; /* vn: 0 for reply */ 1543 s4_rsp.command = 90; /* cd: req granted */ 1544 s4_rsp.dest_port = 0; /* ignored */ 1545 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1546 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1547 fatal_fr(r, "channel %d: append reply", c->self); 1548 return 1; 1549 } 1550 1551 /* try to decode a socks5 header */ 1552 #define SSH_SOCKS5_AUTHDONE 0x1000 1553 #define SSH_SOCKS5_NOAUTH 0x00 1554 #define SSH_SOCKS5_IPV4 0x01 1555 #define SSH_SOCKS5_DOMAIN 0x03 1556 #define SSH_SOCKS5_IPV6 0x04 1557 #define SSH_SOCKS5_CONNECT 0x01 1558 #define SSH_SOCKS5_SUCCESS 0x00 1559 1560 static int 1561 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1562 { 1563 /* XXX use get/put_u8 instead of trusting struct padding */ 1564 struct { 1565 u_int8_t version; 1566 u_int8_t command; 1567 u_int8_t reserved; 1568 u_int8_t atyp; 1569 } s5_req, s5_rsp; 1570 u_int16_t dest_port; 1571 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1572 const u_char *p; 1573 u_int have, need, i, found, nmethods, addrlen, af; 1574 int r; 1575 1576 debug2("channel %d: decode socks5", c->self); 1577 p = sshbuf_ptr(input); 1578 if (p[0] != 0x05) 1579 return -1; 1580 have = sshbuf_len(input); 1581 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1582 /* format: ver | nmethods | methods */ 1583 if (have < 2) 1584 return 0; 1585 nmethods = p[1]; 1586 if (have < nmethods + 2) 1587 return 0; 1588 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1589 for (found = 0, i = 2; i < nmethods + 2; i++) { 1590 if (p[i] == SSH_SOCKS5_NOAUTH) { 1591 found = 1; 1592 break; 1593 } 1594 } 1595 if (!found) { 1596 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1597 c->self); 1598 return -1; 1599 } 1600 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1601 fatal_fr(r, "channel %d: consume", c->self); 1602 /* version, method */ 1603 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1604 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1605 fatal_fr(r, "channel %d: append reply", c->self); 1606 c->flags |= SSH_SOCKS5_AUTHDONE; 1607 debug2("channel %d: socks5 auth done", c->self); 1608 return 0; /* need more */ 1609 } 1610 debug2("channel %d: socks5 post auth", c->self); 1611 if (have < sizeof(s5_req)+1) 1612 return 0; /* need more */ 1613 memcpy(&s5_req, p, sizeof(s5_req)); 1614 if (s5_req.version != 0x05 || 1615 s5_req.command != SSH_SOCKS5_CONNECT || 1616 s5_req.reserved != 0x00) { 1617 debug2("channel %d: only socks5 connect supported", c->self); 1618 return -1; 1619 } 1620 switch (s5_req.atyp){ 1621 case SSH_SOCKS5_IPV4: 1622 addrlen = 4; 1623 af = AF_INET; 1624 break; 1625 case SSH_SOCKS5_DOMAIN: 1626 addrlen = p[sizeof(s5_req)]; 1627 af = -1; 1628 break; 1629 case SSH_SOCKS5_IPV6: 1630 addrlen = 16; 1631 af = AF_INET6; 1632 break; 1633 default: 1634 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1635 return -1; 1636 } 1637 need = sizeof(s5_req) + addrlen + 2; 1638 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1639 need++; 1640 if (have < need) 1641 return 0; 1642 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1643 fatal_fr(r, "channel %d: consume", c->self); 1644 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1645 /* host string length */ 1646 if ((r = sshbuf_consume(input, 1)) != 0) 1647 fatal_fr(r, "channel %d: consume", c->self); 1648 } 1649 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1650 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1651 debug_r(r, "channel %d: parse addr/port", c->self); 1652 return -1; 1653 } 1654 dest_addr[addrlen] = '\0'; 1655 free(c->path); 1656 c->path = NULL; 1657 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1658 if (addrlen >= NI_MAXHOST) { 1659 error("channel %d: dynamic request: socks5 hostname " 1660 "\"%.100s\" too long", c->self, dest_addr); 1661 return -1; 1662 } 1663 c->path = xstrdup(dest_addr); 1664 } else { 1665 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1666 return -1; 1667 c->path = xstrdup(ntop); 1668 } 1669 c->host_port = ntohs(dest_port); 1670 1671 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1672 c->self, c->path, c->host_port, s5_req.command); 1673 1674 s5_rsp.version = 0x05; 1675 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1676 s5_rsp.reserved = 0; /* ignored */ 1677 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1678 dest_port = 0; /* ignored */ 1679 1680 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1681 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1682 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1683 fatal_fr(r, "channel %d: append reply", c->self); 1684 return 1; 1685 } 1686 1687 Channel * 1688 channel_connect_stdio_fwd(struct ssh *ssh, 1689 const char *host_to_connect, int port_to_connect, 1690 int in, int out, int nonblock) 1691 { 1692 Channel *c; 1693 1694 debug_f("%s:%d", host_to_connect, port_to_connect); 1695 1696 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1697 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1698 0, "stdio-forward", nonblock); 1699 1700 c->path = xstrdup(host_to_connect); 1701 c->host_port = port_to_connect; 1702 c->listening_port = 0; 1703 c->force_drain = 1; 1704 1705 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1706 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1707 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1708 1709 return c; 1710 } 1711 1712 /* dynamic port forwarding */ 1713 static void 1714 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1715 { 1716 const u_char *p; 1717 u_int have; 1718 int ret; 1719 1720 c->io_want = 0; 1721 have = sshbuf_len(c->input); 1722 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1723 /* sshbuf_dump(c->input, stderr); */ 1724 /* check if the fixed size part of the packet is in buffer. */ 1725 if (have < 3) { 1726 /* need more */ 1727 c->io_want |= SSH_CHAN_IO_RFD; 1728 return; 1729 } 1730 /* try to guess the protocol */ 1731 p = sshbuf_ptr(c->input); 1732 /* XXX sshbuf_peek_u8? */ 1733 switch (p[0]) { 1734 case 0x04: 1735 ret = channel_decode_socks4(c, c->input, c->output); 1736 break; 1737 case 0x05: 1738 ret = channel_decode_socks5(c, c->input, c->output); 1739 break; 1740 default: 1741 ret = -1; 1742 break; 1743 } 1744 if (ret < 0) { 1745 chan_mark_dead(ssh, c); 1746 } else if (ret == 0) { 1747 debug2("channel %d: pre_dynamic: need more", c->self); 1748 /* need more */ 1749 c->io_want |= SSH_CHAN_IO_RFD; 1750 if (sshbuf_len(c->output)) 1751 c->io_want |= SSH_CHAN_IO_WFD; 1752 } else { 1753 /* switch to the next state */ 1754 c->type = SSH_CHANNEL_OPENING; 1755 port_open_helper(ssh, c, "direct-tcpip"); 1756 } 1757 } 1758 1759 /* simulate read-error */ 1760 static void 1761 rdynamic_close(struct ssh *ssh, Channel *c) 1762 { 1763 c->type = SSH_CHANNEL_OPEN; 1764 channel_force_close(ssh, c, 0); 1765 } 1766 1767 /* reverse dynamic port forwarding */ 1768 static void 1769 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1770 { 1771 const u_char *p; 1772 u_int have, len; 1773 int r, ret; 1774 1775 have = sshbuf_len(c->output); 1776 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1777 /* sshbuf_dump(c->output, stderr); */ 1778 /* EOF received */ 1779 if (c->flags & CHAN_EOF_RCVD) { 1780 if ((r = sshbuf_consume(c->output, have)) != 0) 1781 fatal_fr(r, "channel %d: consume", c->self); 1782 rdynamic_close(ssh, c); 1783 return; 1784 } 1785 /* check if the fixed size part of the packet is in buffer. */ 1786 if (have < 3) 1787 return; 1788 /* try to guess the protocol */ 1789 p = sshbuf_ptr(c->output); 1790 switch (p[0]) { 1791 case 0x04: 1792 /* switch input/output for reverse forwarding */ 1793 ret = channel_decode_socks4(c, c->output, c->input); 1794 break; 1795 case 0x05: 1796 ret = channel_decode_socks5(c, c->output, c->input); 1797 break; 1798 default: 1799 ret = -1; 1800 break; 1801 } 1802 if (ret < 0) { 1803 rdynamic_close(ssh, c); 1804 } else if (ret == 0) { 1805 debug2("channel %d: pre_rdynamic: need more", c->self); 1806 /* send socks request to peer */ 1807 len = sshbuf_len(c->input); 1808 if (len > 0 && len < c->remote_window) { 1809 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1810 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1811 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1812 (r = sshpkt_send(ssh)) != 0) { 1813 fatal_fr(r, "channel %i: rdynamic", c->self); 1814 } 1815 if ((r = sshbuf_consume(c->input, len)) != 0) 1816 fatal_fr(r, "channel %d: consume", c->self); 1817 c->remote_window -= len; 1818 } 1819 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1820 /* the connect failed */ 1821 rdynamic_close(ssh, c); 1822 } 1823 } 1824 1825 /* This is our fake X11 server socket. */ 1826 static void 1827 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1828 { 1829 Channel *nc; 1830 struct sockaddr_storage addr; 1831 int r, newsock, oerrno, remote_port; 1832 socklen_t addrlen; 1833 char buf[16384], *remote_ipaddr; 1834 1835 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1836 return; 1837 1838 debug("X11 connection requested."); 1839 addrlen = sizeof(addr); 1840 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1841 if (c->single_connection) { 1842 oerrno = errno; 1843 debug2("single_connection: closing X11 listener."); 1844 channel_close_fd(ssh, c, &c->sock); 1845 chan_mark_dead(ssh, c); 1846 errno = oerrno; 1847 } 1848 if (newsock == -1) { 1849 if (errno != EINTR && errno != EWOULDBLOCK && 1850 errno != ECONNABORTED) 1851 error("accept: %.100s", strerror(errno)); 1852 if (errno == EMFILE || errno == ENFILE) 1853 c->notbefore = monotime() + 1; 1854 return; 1855 } 1856 set_nodelay(newsock); 1857 remote_ipaddr = get_peer_ipaddr(newsock); 1858 remote_port = get_peer_port(newsock); 1859 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1860 remote_ipaddr, remote_port); 1861 1862 nc = channel_new(ssh, "x11-connection", 1863 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1864 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1865 open_preamble(ssh, __func__, nc, "x11"); 1866 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1867 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1868 fatal_fr(r, "channel %i: reply", c->self); 1869 } 1870 if ((r = sshpkt_send(ssh)) != 0) 1871 fatal_fr(r, "channel %i: send", c->self); 1872 free(remote_ipaddr); 1873 } 1874 1875 static void 1876 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1877 { 1878 char *local_ipaddr = get_local_ipaddr(c->sock); 1879 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1880 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1881 int remote_port = get_peer_port(c->sock); 1882 int r; 1883 1884 if (remote_port == -1) { 1885 /* Fake addr/port to appease peers that validate it (Tectia) */ 1886 free(remote_ipaddr); 1887 remote_ipaddr = xstrdup("127.0.0.1"); 1888 remote_port = 65535; 1889 } 1890 1891 free(c->remote_name); 1892 xasprintf(&c->remote_name, 1893 "%s: listening port %d for %.100s port %d, " 1894 "connect from %.200s port %d to %.100s port %d", 1895 rtype, c->listening_port, c->path, c->host_port, 1896 remote_ipaddr, remote_port, local_ipaddr, local_port); 1897 1898 open_preamble(ssh, __func__, c, rtype); 1899 if (strcmp(rtype, "direct-tcpip") == 0) { 1900 /* target host, port */ 1901 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1902 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1903 fatal_fr(r, "channel %i: reply", c->self); 1904 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1905 /* target path */ 1906 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1907 fatal_fr(r, "channel %i: reply", c->self); 1908 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1909 /* listen path */ 1910 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1911 fatal_fr(r, "channel %i: reply", c->self); 1912 } else { 1913 /* listen address, port */ 1914 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1915 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1916 fatal_fr(r, "channel %i: reply", c->self); 1917 } 1918 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1919 /* reserved for future owner/mode info */ 1920 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1921 fatal_fr(r, "channel %i: reply", c->self); 1922 } else { 1923 /* originator host and port */ 1924 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1925 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1926 fatal_fr(r, "channel %i: reply", c->self); 1927 } 1928 if ((r = sshpkt_send(ssh)) != 0) 1929 fatal_fr(r, "channel %i: send", c->self); 1930 free(remote_ipaddr); 1931 free(local_ipaddr); 1932 } 1933 1934 void 1935 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1936 { 1937 ssh->chanctxt->x11_refuse_time = refuse_time; 1938 } 1939 1940 /* 1941 * This socket is listening for connections to a forwarded TCP/IP port. 1942 */ 1943 static void 1944 channel_post_port_listener(struct ssh *ssh, Channel *c) 1945 { 1946 Channel *nc; 1947 struct sockaddr_storage addr; 1948 int newsock, nextstate; 1949 socklen_t addrlen; 1950 char *rtype; 1951 1952 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1953 return; 1954 1955 debug("Connection to port %d forwarding to %.100s port %d requested.", 1956 c->listening_port, c->path, c->host_port); 1957 1958 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1959 nextstate = SSH_CHANNEL_OPENING; 1960 rtype = "forwarded-tcpip"; 1961 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1962 nextstate = SSH_CHANNEL_OPENING; 1963 rtype = "forwarded-streamlocal@openssh.com"; 1964 } else if (c->host_port == PORT_STREAMLOCAL) { 1965 nextstate = SSH_CHANNEL_OPENING; 1966 rtype = "direct-streamlocal@openssh.com"; 1967 } else if (c->host_port == 0) { 1968 nextstate = SSH_CHANNEL_DYNAMIC; 1969 rtype = "dynamic-tcpip"; 1970 } else { 1971 nextstate = SSH_CHANNEL_OPENING; 1972 rtype = "direct-tcpip"; 1973 } 1974 1975 addrlen = sizeof(addr); 1976 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1977 if (newsock == -1) { 1978 if (errno != EINTR && errno != EWOULDBLOCK && 1979 errno != ECONNABORTED) 1980 error("accept: %.100s", strerror(errno)); 1981 if (errno == EMFILE || errno == ENFILE) 1982 c->notbefore = monotime() + 1; 1983 return; 1984 } 1985 if (c->host_port != PORT_STREAMLOCAL) 1986 set_nodelay(newsock); 1987 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1988 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1989 nc->listening_port = c->listening_port; 1990 nc->host_port = c->host_port; 1991 if (c->path != NULL) 1992 nc->path = xstrdup(c->path); 1993 1994 if (nextstate != SSH_CHANNEL_DYNAMIC) 1995 port_open_helper(ssh, nc, rtype); 1996 } 1997 1998 /* 1999 * This is the authentication agent socket listening for connections from 2000 * clients. 2001 */ 2002 static void 2003 channel_post_auth_listener(struct ssh *ssh, Channel *c) 2004 { 2005 Channel *nc; 2006 int r, newsock; 2007 struct sockaddr_storage addr; 2008 socklen_t addrlen; 2009 2010 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2011 return; 2012 2013 addrlen = sizeof(addr); 2014 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2015 if (newsock == -1) { 2016 error("accept from auth socket: %.100s", strerror(errno)); 2017 if (errno == EMFILE || errno == ENFILE) 2018 c->notbefore = monotime() + 1; 2019 return; 2020 } 2021 nc = channel_new(ssh, "agent-connection", 2022 SSH_CHANNEL_OPENING, newsock, newsock, -1, 2023 c->local_window_max, c->local_maxpacket, 2024 0, "accepted auth socket", 1); 2025 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 2026 if ((r = sshpkt_send(ssh)) != 0) 2027 fatal_fr(r, "channel %i", c->self); 2028 } 2029 2030 static void 2031 channel_post_connecting(struct ssh *ssh, Channel *c) 2032 { 2033 int err = 0, sock, isopen, r; 2034 socklen_t sz = sizeof(err); 2035 2036 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2037 return; 2038 if (!c->have_remote_id) 2039 fatal_f("channel %d: no remote id", c->self); 2040 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2041 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2042 2043 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2044 err = errno; 2045 error("getsockopt SO_ERROR failed"); 2046 } 2047 2048 if (err == 0) { 2049 /* Non-blocking connection completed */ 2050 debug("channel %d: connected to %s port %d", 2051 c->self, c->connect_ctx.host, c->connect_ctx.port); 2052 channel_connect_ctx_free(&c->connect_ctx); 2053 c->type = SSH_CHANNEL_OPEN; 2054 channel_set_used_time(ssh, c); 2055 if (isopen) { 2056 /* no message necessary */ 2057 } else { 2058 if ((r = sshpkt_start(ssh, 2059 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2060 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2061 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2062 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2063 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2064 (r = sshpkt_send(ssh)) != 0) 2065 fatal_fr(r, "channel %i open confirm", c->self); 2066 } 2067 return; 2068 } 2069 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2070 return; 2071 2072 /* Non-blocking connection failed */ 2073 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2074 2075 /* Try next address, if any */ 2076 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2077 /* Exhausted all addresses for this destination */ 2078 error("connect_to %.100s port %d: failed.", 2079 c->connect_ctx.host, c->connect_ctx.port); 2080 channel_connect_ctx_free(&c->connect_ctx); 2081 if (isopen) { 2082 rdynamic_close(ssh, c); 2083 } else { 2084 if ((r = sshpkt_start(ssh, 2085 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2086 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2087 (r = sshpkt_put_u32(ssh, 2088 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2089 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2090 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2091 (r = sshpkt_send(ssh)) != 0) 2092 fatal_fr(r, "channel %i: failure", c->self); 2093 chan_mark_dead(ssh, c); 2094 } 2095 } 2096 2097 /* New non-blocking connection in progress */ 2098 close(c->sock); 2099 c->sock = c->rfd = c->wfd = sock; 2100 } 2101 2102 static int 2103 channel_handle_rfd(struct ssh *ssh, Channel *c) 2104 { 2105 char buf[CHAN_RBUF]; 2106 ssize_t len; 2107 int r, force; 2108 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2109 int pty_zeroread = 0; 2110 2111 #ifdef PTY_ZEROREAD 2112 /* Bug on AIX: read(1) can return 0 for a non-closed fd */ 2113 pty_zeroread = c->isatty; 2114 #endif 2115 2116 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2117 2118 if (!force && (c->io_ready & SSH_CHAN_IO_RFD) == 0) 2119 return 1; 2120 if ((avail = sshbuf_avail(c->input)) == 0) 2121 return 1; /* Shouldn't happen */ 2122 2123 /* 2124 * For "simple" channels (i.e. not datagram or filtered), we can 2125 * read directly to the channel buffer. 2126 */ 2127 if (!pty_zeroread && c->input_filter == NULL && !c->datagram) { 2128 /* Only OPEN channels have valid rwin */ 2129 if (c->type == SSH_CHANNEL_OPEN) { 2130 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2131 return 1; /* shouldn't happen */ 2132 if (maxlen > c->remote_window - have) 2133 maxlen = c->remote_window - have; 2134 } 2135 if (maxlen > avail) 2136 maxlen = avail; 2137 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2138 if (errno == EINTR || (!force && 2139 (errno == EAGAIN || errno == EWOULDBLOCK))) 2140 return 1; 2141 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2142 c->self, c->rfd, maxlen, ssh_err(r)); 2143 goto rfail; 2144 } 2145 if (nr != 0) 2146 channel_set_used_time(ssh, c); 2147 return 1; 2148 } 2149 2150 errno = 0; 2151 len = read(c->rfd, buf, sizeof(buf)); 2152 /* fixup AIX zero-length read with errno set to look more like errors */ 2153 if (pty_zeroread && len == 0 && errno != 0) 2154 len = -1; 2155 if (len == -1 && (errno == EINTR || 2156 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 2157 return 1; 2158 if (len < 0 || (!pty_zeroread && len == 0)) { 2159 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2160 c->self, c->rfd, len, 2161 len == 0 ? "closed" : strerror(errno)); 2162 rfail: 2163 if (c->type != SSH_CHANNEL_OPEN) { 2164 debug2("channel %d: not open", c->self); 2165 chan_mark_dead(ssh, c); 2166 return -1; 2167 } else { 2168 chan_read_failed(ssh, c); 2169 } 2170 return -1; 2171 } 2172 channel_set_used_time(ssh, c); 2173 if (c->input_filter != NULL) { 2174 if (c->input_filter(ssh, c, buf, len) == -1) { 2175 debug2("channel %d: filter stops", c->self); 2176 chan_read_failed(ssh, c); 2177 } 2178 } else if (c->datagram) { 2179 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2180 fatal_fr(r, "channel %i: put datagram", c->self); 2181 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2182 fatal_fr(r, "channel %i: put data", c->self); 2183 2184 return 1; 2185 } 2186 2187 static int 2188 channel_handle_wfd(struct ssh *ssh, Channel *c) 2189 { 2190 struct termios tio; 2191 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2192 size_t dlen, olen = 0; 2193 int r, len; 2194 2195 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2196 return 1; 2197 if (sshbuf_len(c->output) == 0) 2198 return 1; 2199 2200 /* Send buffered output data to the socket. */ 2201 olen = sshbuf_len(c->output); 2202 if (c->output_filter != NULL) { 2203 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2204 debug2("channel %d: filter stops", c->self); 2205 if (c->type != SSH_CHANNEL_OPEN) 2206 chan_mark_dead(ssh, c); 2207 else 2208 chan_write_failed(ssh, c); 2209 return -1; 2210 } 2211 } else if (c->datagram) { 2212 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2213 fatal_fr(r, "channel %i: get datagram", c->self); 2214 buf = data; 2215 } else { 2216 buf = data = sshbuf_mutable_ptr(c->output); 2217 dlen = sshbuf_len(c->output); 2218 } 2219 2220 if (c->datagram) { 2221 /* ignore truncated writes, datagrams might get lost */ 2222 len = write(c->wfd, buf, dlen); 2223 free(data); 2224 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2225 errno == EWOULDBLOCK)) 2226 return 1; 2227 if (len <= 0) 2228 goto write_fail; 2229 goto out; 2230 } 2231 2232 #ifdef _AIX 2233 /* XXX: Later AIX versions can't push as much data to tty */ 2234 if (c->wfd_isatty) 2235 dlen = MINIMUM(dlen, 8*1024); 2236 #endif 2237 2238 len = write(c->wfd, buf, dlen); 2239 if (len == -1 && 2240 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 2241 return 1; 2242 if (len <= 0) { 2243 write_fail: 2244 if (c->type != SSH_CHANNEL_OPEN) { 2245 debug2("channel %d: not open", c->self); 2246 chan_mark_dead(ssh, c); 2247 return -1; 2248 } else { 2249 chan_write_failed(ssh, c); 2250 } 2251 return -1; 2252 } 2253 channel_set_used_time(ssh, c); 2254 #ifndef BROKEN_TCGETATTR_ICANON 2255 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2256 if (tcgetattr(c->wfd, &tio) == 0 && 2257 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2258 /* 2259 * Simulate echo to reduce the impact of 2260 * traffic analysis. We need to match the 2261 * size of a SSH2_MSG_CHANNEL_DATA message 2262 * (4 byte channel id + buf) 2263 */ 2264 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2265 (r = sshpkt_send(ssh)) != 0) 2266 fatal_fr(r, "channel %i: ignore", c->self); 2267 } 2268 } 2269 #endif /* BROKEN_TCGETATTR_ICANON */ 2270 if ((r = sshbuf_consume(c->output, len)) != 0) 2271 fatal_fr(r, "channel %i: consume", c->self); 2272 out: 2273 c->local_consumed += olen - sshbuf_len(c->output); 2274 2275 return 1; 2276 } 2277 2278 static int 2279 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2280 { 2281 int r; 2282 ssize_t len; 2283 2284 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2285 return 1; 2286 if (sshbuf_len(c->extended) == 0) 2287 return 1; 2288 2289 len = write(c->efd, sshbuf_ptr(c->extended), 2290 sshbuf_len(c->extended)); 2291 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2292 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2293 errno == EWOULDBLOCK)) 2294 return 1; 2295 if (len <= 0) { 2296 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2297 channel_close_fd(ssh, c, &c->efd); 2298 } else { 2299 if ((r = sshbuf_consume(c->extended, len)) != 0) 2300 fatal_fr(r, "channel %i: consume", c->self); 2301 c->local_consumed += len; 2302 channel_set_used_time(ssh, c); 2303 } 2304 return 1; 2305 } 2306 2307 static int 2308 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2309 { 2310 char buf[CHAN_RBUF]; 2311 ssize_t len; 2312 int r, force; 2313 2314 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2315 2316 if (!force && (c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2317 return 1; 2318 2319 len = read(c->efd, buf, sizeof(buf)); 2320 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2321 if (len == -1 && (errno == EINTR || ((errno == EAGAIN || 2322 errno == EWOULDBLOCK) && !force))) 2323 return 1; 2324 if (len <= 0) { 2325 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2326 channel_close_fd(ssh, c, &c->efd); 2327 return 1; 2328 } 2329 channel_set_used_time(ssh, c); 2330 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2331 debug3("channel %d: discard efd", c->self); 2332 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2333 fatal_fr(r, "channel %i: append", c->self); 2334 return 1; 2335 } 2336 2337 static int 2338 channel_handle_efd(struct ssh *ssh, Channel *c) 2339 { 2340 if (c->efd == -1) 2341 return 1; 2342 2343 /** XXX handle drain efd, too */ 2344 2345 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2346 return channel_handle_efd_write(ssh, c); 2347 else if (c->extended_usage == CHAN_EXTENDED_READ || 2348 c->extended_usage == CHAN_EXTENDED_IGNORE) 2349 return channel_handle_efd_read(ssh, c); 2350 2351 return 1; 2352 } 2353 2354 static int 2355 channel_check_window(struct ssh *ssh, Channel *c) 2356 { 2357 int r; 2358 2359 if (c->type == SSH_CHANNEL_OPEN && 2360 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2361 ((c->local_window_max - c->local_window > 2362 c->local_maxpacket*3) || 2363 c->local_window < c->local_window_max/2) && 2364 c->local_consumed > 0) { 2365 if (!c->have_remote_id) 2366 fatal_f("channel %d: no remote id", c->self); 2367 if ((r = sshpkt_start(ssh, 2368 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2369 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2370 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2371 (r = sshpkt_send(ssh)) != 0) { 2372 fatal_fr(r, "channel %i", c->self); 2373 } 2374 debug2("channel %d: window %d sent adjust %d", c->self, 2375 c->local_window, c->local_consumed); 2376 c->local_window += c->local_consumed; 2377 c->local_consumed = 0; 2378 } 2379 return 1; 2380 } 2381 2382 static void 2383 channel_post_open(struct ssh *ssh, Channel *c) 2384 { 2385 channel_handle_rfd(ssh, c); 2386 channel_handle_wfd(ssh, c); 2387 channel_handle_efd(ssh, c); 2388 channel_check_window(ssh, c); 2389 } 2390 2391 static u_int 2392 read_mux(struct ssh *ssh, Channel *c, u_int need) 2393 { 2394 char buf[CHAN_RBUF]; 2395 ssize_t len; 2396 u_int rlen; 2397 int r; 2398 2399 if (sshbuf_len(c->input) < need) { 2400 rlen = need - sshbuf_len(c->input); 2401 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2402 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2403 return sshbuf_len(c->input); 2404 if (len <= 0) { 2405 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2406 c->self, c->rfd, len); 2407 chan_read_failed(ssh, c); 2408 return 0; 2409 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2410 fatal_fr(r, "channel %i: append", c->self); 2411 } 2412 return sshbuf_len(c->input); 2413 } 2414 2415 static void 2416 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2417 { 2418 u_int need; 2419 2420 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2421 return; 2422 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2423 return; 2424 if (c->mux_pause) 2425 return; 2426 2427 /* 2428 * Don't not read past the precise end of packets to 2429 * avoid disrupting fd passing. 2430 */ 2431 if (read_mux(ssh, c, 4) < 4) /* read header */ 2432 return; 2433 /* XXX sshbuf_peek_u32 */ 2434 need = PEEK_U32(sshbuf_ptr(c->input)); 2435 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2436 if (need > CHANNEL_MUX_MAX_PACKET) { 2437 debug2("channel %d: packet too big %u > %u", 2438 c->self, CHANNEL_MUX_MAX_PACKET, need); 2439 chan_rcvd_oclose(ssh, c); 2440 return; 2441 } 2442 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2443 return; 2444 if (c->mux_rcb(ssh, c) != 0) { 2445 debug("channel %d: mux_rcb failed", c->self); 2446 chan_mark_dead(ssh, c); 2447 return; 2448 } 2449 } 2450 2451 static void 2452 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2453 { 2454 ssize_t len; 2455 int r; 2456 2457 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2458 return; 2459 if (sshbuf_len(c->output) == 0) 2460 return; 2461 2462 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2463 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2464 return; 2465 if (len <= 0) { 2466 chan_mark_dead(ssh, c); 2467 return; 2468 } 2469 if ((r = sshbuf_consume(c->output, len)) != 0) 2470 fatal_fr(r, "channel %i: consume", c->self); 2471 } 2472 2473 static void 2474 channel_post_mux_client(struct ssh *ssh, Channel *c) 2475 { 2476 channel_post_mux_client_read(ssh, c); 2477 channel_post_mux_client_write(ssh, c); 2478 } 2479 2480 static void 2481 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2482 { 2483 Channel *nc; 2484 struct sockaddr_storage addr; 2485 socklen_t addrlen; 2486 int newsock; 2487 uid_t euid; 2488 gid_t egid; 2489 2490 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2491 return; 2492 2493 debug("multiplexing control connection"); 2494 2495 /* 2496 * Accept connection on control socket 2497 */ 2498 memset(&addr, 0, sizeof(addr)); 2499 addrlen = sizeof(addr); 2500 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2501 &addrlen)) == -1) { 2502 error_f("accept: %s", strerror(errno)); 2503 if (errno == EMFILE || errno == ENFILE) 2504 c->notbefore = monotime() + 1; 2505 return; 2506 } 2507 2508 if (getpeereid(newsock, &euid, &egid) == -1) { 2509 error_f("getpeereid failed: %s", strerror(errno)); 2510 close(newsock); 2511 return; 2512 } 2513 if ((euid != 0) && (getuid() != euid)) { 2514 error("multiplex uid mismatch: peer euid %u != uid %u", 2515 (u_int)euid, (u_int)getuid()); 2516 close(newsock); 2517 return; 2518 } 2519 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2520 newsock, newsock, -1, c->local_window_max, 2521 c->local_maxpacket, 0, "mux-control", 1); 2522 nc->mux_rcb = c->mux_rcb; 2523 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2524 /* establish state */ 2525 nc->mux_rcb(ssh, nc); 2526 /* mux state transitions must not elicit protocol messages */ 2527 nc->flags |= CHAN_LOCAL; 2528 } 2529 2530 static void 2531 channel_handler_init(struct ssh_channels *sc) 2532 { 2533 chan_fn **pre, **post; 2534 2535 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2536 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2537 fatal_f("allocation failed"); 2538 2539 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2540 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2541 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2542 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2543 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2544 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2545 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2546 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2547 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2548 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2549 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2550 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2551 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2552 2553 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2554 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2555 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2556 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2557 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2558 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2559 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2560 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2561 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2562 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2563 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2564 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2565 2566 sc->channel_pre = pre; 2567 sc->channel_post = post; 2568 } 2569 2570 /* gc dead channels */ 2571 static void 2572 channel_garbage_collect(struct ssh *ssh, Channel *c) 2573 { 2574 if (c == NULL) 2575 return; 2576 if (c->detach_user != NULL) { 2577 if (!chan_is_dead(ssh, c, c->detach_close)) 2578 return; 2579 2580 debug2("channel %d: gc: notify user", c->self); 2581 c->detach_user(ssh, c->self, 0, NULL); 2582 /* if we still have a callback */ 2583 if (c->detach_user != NULL) 2584 return; 2585 debug2("channel %d: gc: user detached", c->self); 2586 } 2587 if (!chan_is_dead(ssh, c, 1)) 2588 return; 2589 debug2("channel %d: garbage collecting", c->self); 2590 channel_free(ssh, c); 2591 } 2592 2593 enum channel_table { CHAN_PRE, CHAN_POST }; 2594 2595 static void 2596 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2597 { 2598 struct ssh_channels *sc = ssh->chanctxt; 2599 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2600 u_int i, oalloc; 2601 Channel *c; 2602 time_t now; 2603 2604 now = monotime(); 2605 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2606 c = sc->channels[i]; 2607 if (c == NULL) 2608 continue; 2609 /* Try to keep IO going while rekeying */ 2610 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2611 continue; 2612 if (c->delayed) { 2613 if (table == CHAN_PRE) 2614 c->delayed = 0; 2615 else 2616 continue; 2617 } 2618 if (ftab[c->type] != NULL) { 2619 if (table == CHAN_PRE && c->type == SSH_CHANNEL_OPEN && 2620 channel_get_expiry(ssh, c) != 0 && 2621 now >= channel_get_expiry(ssh, c)) { 2622 /* channel closed for inactivity */ 2623 verbose("channel %d: closing after %u seconds " 2624 "of inactivity", c->self, 2625 c->inactive_deadline); 2626 channel_force_close(ssh, c, 1); 2627 } else if (c->notbefore <= now) { 2628 /* Run handlers that are not paused. */ 2629 (*ftab[c->type])(ssh, c); 2630 /* inactivity timeouts must interrupt poll() */ 2631 if (timeout != NULL && 2632 c->type == SSH_CHANNEL_OPEN && 2633 channel_get_expiry(ssh, c) != 0) { 2634 ptimeout_deadline_monotime(timeout, 2635 channel_get_expiry(ssh, c)); 2636 } 2637 } else if (timeout != NULL) { 2638 /* 2639 * Arrange for poll() wakeup when channel pause 2640 * timer expires. 2641 */ 2642 ptimeout_deadline_monotime(timeout, 2643 c->notbefore); 2644 } 2645 } 2646 channel_garbage_collect(ssh, c); 2647 } 2648 } 2649 2650 /* 2651 * Create sockets before preparing IO. 2652 * This is necessary for things that need to happen after reading 2653 * the network-input but need to be completed before IO event setup, e.g. 2654 * because they may create new channels. 2655 */ 2656 static void 2657 channel_before_prepare_io(struct ssh *ssh) 2658 { 2659 struct ssh_channels *sc = ssh->chanctxt; 2660 Channel *c; 2661 u_int i, oalloc; 2662 2663 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2664 c = sc->channels[i]; 2665 if (c == NULL) 2666 continue; 2667 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2668 channel_before_prepare_io_rdynamic(ssh, c); 2669 } 2670 } 2671 2672 static void 2673 dump_channel_poll(const char *func, const char *what, Channel *c, 2674 u_int pollfd_offset, struct pollfd *pfd) 2675 { 2676 #ifdef DEBUG_CHANNEL_POLL 2677 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2678 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2679 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2680 c->rfd, c->wfd, c->efd, c->sock, 2681 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2682 c->io_want, c->io_ready, 2683 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2684 #endif 2685 } 2686 2687 /* Prepare pollfd entries for a single channel */ 2688 static void 2689 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2690 struct pollfd *pfd, u_int npfd) 2691 { 2692 u_int ev, p = *next_pollfd; 2693 2694 if (c == NULL) 2695 return; 2696 if (p + 4 > npfd) { 2697 /* Shouldn't happen */ 2698 fatal_f("channel %d: bad pfd offset %u (max %u)", 2699 c->self, p, npfd); 2700 } 2701 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2702 /* 2703 * prepare c->rfd 2704 * 2705 * This is a special case, since c->rfd might be the same as 2706 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2707 * IO too. 2708 */ 2709 if (c->rfd != -1) { 2710 ev = 0; 2711 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2712 ev |= POLLIN; 2713 /* rfd == wfd */ 2714 if (c->wfd == c->rfd) { 2715 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2716 ev |= POLLOUT; 2717 } 2718 /* rfd == efd */ 2719 if (c->efd == c->rfd) { 2720 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2721 ev |= POLLIN; 2722 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2723 ev |= POLLOUT; 2724 } 2725 /* rfd == sock */ 2726 if (c->sock == c->rfd) { 2727 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2728 ev |= POLLIN; 2729 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2730 ev |= POLLOUT; 2731 } 2732 /* Pack a pfd entry if any event armed for this fd */ 2733 if (ev != 0) { 2734 c->pfds[0] = p; 2735 pfd[p].fd = c->rfd; 2736 pfd[p].events = ev; 2737 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2738 p++; 2739 } 2740 } 2741 /* prepare c->wfd if wanting IO and not already handled above */ 2742 if (c->wfd != -1 && c->rfd != c->wfd) { 2743 ev = 0; 2744 if ((c->io_want & SSH_CHAN_IO_WFD)) 2745 ev |= POLLOUT; 2746 /* Pack a pfd entry if any event armed for this fd */ 2747 if (ev != 0) { 2748 c->pfds[1] = p; 2749 pfd[p].fd = c->wfd; 2750 pfd[p].events = ev; 2751 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2752 p++; 2753 } 2754 } 2755 /* prepare c->efd if wanting IO and not already handled above */ 2756 if (c->efd != -1 && c->rfd != c->efd) { 2757 ev = 0; 2758 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2759 ev |= POLLIN; 2760 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2761 ev |= POLLOUT; 2762 /* Pack a pfd entry if any event armed for this fd */ 2763 if (ev != 0) { 2764 c->pfds[2] = p; 2765 pfd[p].fd = c->efd; 2766 pfd[p].events = ev; 2767 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2768 p++; 2769 } 2770 } 2771 /* prepare c->sock if wanting IO and not already handled above */ 2772 if (c->sock != -1 && c->rfd != c->sock) { 2773 ev = 0; 2774 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2775 ev |= POLLIN; 2776 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2777 ev |= POLLOUT; 2778 /* Pack a pfd entry if any event armed for this fd */ 2779 if (ev != 0) { 2780 c->pfds[3] = p; 2781 pfd[p].fd = c->sock; 2782 pfd[p].events = 0; 2783 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2784 p++; 2785 } 2786 } 2787 *next_pollfd = p; 2788 } 2789 2790 /* * Allocate/prepare poll structure */ 2791 void 2792 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2793 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2794 { 2795 struct ssh_channels *sc = ssh->chanctxt; 2796 u_int i, oalloc, p, npfd = npfd_reserved; 2797 2798 channel_before_prepare_io(ssh); /* might create a new channel */ 2799 /* clear out I/O flags from last poll */ 2800 for (i = 0; i < sc->channels_alloc; i++) { 2801 if (sc->channels[i] == NULL) 2802 continue; 2803 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2804 } 2805 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2806 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2807 fatal_f("too many channels"); /* shouldn't happen */ 2808 npfd += sc->channels_alloc * 4; 2809 if (npfd > *npfd_allocp) { 2810 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2811 npfd, sizeof(**pfdp)); 2812 *npfd_allocp = npfd; 2813 } 2814 *npfd_activep = npfd_reserved; 2815 oalloc = sc->channels_alloc; 2816 2817 channel_handler(ssh, CHAN_PRE, timeout); 2818 2819 if (oalloc != sc->channels_alloc) { 2820 /* shouldn't happen */ 2821 fatal_f("channels_alloc changed during CHAN_PRE " 2822 "(was %u, now %u)", oalloc, sc->channels_alloc); 2823 } 2824 2825 /* Prepare pollfd */ 2826 p = npfd_reserved; 2827 for (i = 0; i < sc->channels_alloc; i++) 2828 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2829 *npfd_activep = p; 2830 } 2831 2832 static void 2833 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2834 const char *what, u_int revents_mask, u_int ready) 2835 { 2836 struct pollfd *pfd = &pfds[p]; 2837 2838 if (fd == -1) 2839 return; 2840 if (p == -1 || (u_int)p >= npfd) 2841 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2842 dump_channel_poll(__func__, what, c, p, pfd); 2843 if (pfd->fd != fd) { 2844 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2845 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2846 c->rfd, c->wfd, c->efd, c->sock); 2847 } 2848 if ((pfd->revents & POLLNVAL) != 0) { 2849 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2850 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2851 } 2852 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2853 c->io_ready |= ready & c->io_want; 2854 } 2855 2856 /* 2857 * After poll, perform any appropriate operations for channels which have 2858 * events pending. 2859 */ 2860 void 2861 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2862 { 2863 struct ssh_channels *sc = ssh->chanctxt; 2864 u_int i; 2865 int p; 2866 Channel *c; 2867 2868 #ifdef DEBUG_CHANNEL_POLL 2869 for (p = 0; p < (int)npfd; p++) { 2870 if (pfd[p].revents == 0) 2871 continue; 2872 debug_f("pfd[%u].fd %d rev 0x%04x", 2873 p, pfd[p].fd, pfd[p].revents); 2874 } 2875 #endif 2876 2877 /* Convert pollfd into c->io_ready */ 2878 for (i = 0; i < sc->channels_alloc; i++) { 2879 c = sc->channels[i]; 2880 if (c == NULL) 2881 continue; 2882 /* if rfd is shared with efd/sock then wfd should be too */ 2883 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2884 (c->rfd == c->efd || c->rfd == c->sock)) { 2885 /* Shouldn't happen */ 2886 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2887 c->self, c->rfd, c->wfd, c->efd, c->sock); 2888 } 2889 c->io_ready = 0; 2890 /* rfd, potentially shared with wfd, efd and sock */ 2891 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2892 fd_ready(c, p, pfd, npfd, c->rfd, 2893 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2894 if (c->rfd == c->wfd) { 2895 fd_ready(c, p, pfd, npfd, c->wfd, 2896 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2897 } 2898 if (c->rfd == c->efd) { 2899 fd_ready(c, p, pfd, npfd, c->efd, 2900 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2901 fd_ready(c, p, pfd, npfd, c->efd, 2902 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2903 } 2904 if (c->rfd == c->sock) { 2905 fd_ready(c, p, pfd, npfd, c->sock, 2906 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2907 fd_ready(c, p, pfd, npfd, c->sock, 2908 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2909 } 2910 dump_channel_poll(__func__, "rfd", c, p, pfd); 2911 } 2912 /* wfd */ 2913 if (c->wfd != -1 && c->wfd != c->rfd && 2914 (p = c->pfds[1]) != -1) { 2915 fd_ready(c, p, pfd, npfd, c->wfd, 2916 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2917 dump_channel_poll(__func__, "wfd", c, p, pfd); 2918 } 2919 /* efd */ 2920 if (c->efd != -1 && c->efd != c->rfd && 2921 (p = c->pfds[2]) != -1) { 2922 fd_ready(c, p, pfd, npfd, c->efd, 2923 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2924 fd_ready(c, p, pfd, npfd, c->efd, 2925 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2926 dump_channel_poll(__func__, "efd", c, p, pfd); 2927 } 2928 /* sock */ 2929 if (c->sock != -1 && c->sock != c->rfd && 2930 (p = c->pfds[3]) != -1) { 2931 fd_ready(c, p, pfd, npfd, c->sock, 2932 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2933 fd_ready(c, p, pfd, npfd, c->sock, 2934 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2935 dump_channel_poll(__func__, "sock", c, p, pfd); 2936 } 2937 } 2938 channel_handler(ssh, CHAN_POST, NULL); 2939 } 2940 2941 /* 2942 * Enqueue data for channels with open or draining c->input. 2943 * Returns non-zero if a packet was enqueued. 2944 */ 2945 static int 2946 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2947 { 2948 size_t len, plen; 2949 const u_char *pkt; 2950 int r; 2951 2952 if ((len = sshbuf_len(c->input)) == 0) { 2953 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2954 /* 2955 * input-buffer is empty and read-socket shutdown: 2956 * tell peer, that we will not send more data: 2957 * send IEOF. 2958 * hack for extended data: delay EOF if EFD still 2959 * in use. 2960 */ 2961 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2962 debug2("channel %d: " 2963 "ibuf_empty delayed efd %d/(%zu)", 2964 c->self, c->efd, sshbuf_len(c->extended)); 2965 else 2966 chan_ibuf_empty(ssh, c); 2967 } 2968 return 0; 2969 } 2970 2971 if (!c->have_remote_id) 2972 fatal_f("channel %d: no remote id", c->self); 2973 2974 if (c->datagram) { 2975 /* Check datagram will fit; drop if not */ 2976 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2977 fatal_fr(r, "channel %i: get datagram", c->self); 2978 /* 2979 * XXX this does tail-drop on the datagram queue which is 2980 * usually suboptimal compared to head-drop. Better to have 2981 * backpressure at read time? (i.e. read + discard) 2982 */ 2983 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2984 debug("channel %d: datagram too big", c->self); 2985 return 0; 2986 } 2987 /* Enqueue it */ 2988 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2989 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2990 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2991 (r = sshpkt_send(ssh)) != 0) 2992 fatal_fr(r, "channel %i: send datagram", c->self); 2993 c->remote_window -= plen; 2994 return 1; 2995 } 2996 2997 /* Enqueue packet for buffered data. */ 2998 if (len > c->remote_window) 2999 len = c->remote_window; 3000 if (len > c->remote_maxpacket) 3001 len = c->remote_maxpacket; 3002 if (len == 0) 3003 return 0; 3004 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 3005 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3006 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 3007 (r = sshpkt_send(ssh)) != 0) 3008 fatal_fr(r, "channel %i: send data", c->self); 3009 if ((r = sshbuf_consume(c->input, len)) != 0) 3010 fatal_fr(r, "channel %i: consume", c->self); 3011 c->remote_window -= len; 3012 return 1; 3013 } 3014 3015 /* 3016 * Enqueue data for channels with open c->extended in read mode. 3017 * Returns non-zero if a packet was enqueued. 3018 */ 3019 static int 3020 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 3021 { 3022 size_t len; 3023 int r; 3024 3025 if ((len = sshbuf_len(c->extended)) == 0) 3026 return 0; 3027 3028 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 3029 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 3030 if (len > c->remote_window) 3031 len = c->remote_window; 3032 if (len > c->remote_maxpacket) 3033 len = c->remote_maxpacket; 3034 if (len == 0) 3035 return 0; 3036 if (!c->have_remote_id) 3037 fatal_f("channel %d: no remote id", c->self); 3038 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 3039 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3040 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 3041 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 3042 (r = sshpkt_send(ssh)) != 0) 3043 fatal_fr(r, "channel %i: data", c->self); 3044 if ((r = sshbuf_consume(c->extended, len)) != 0) 3045 fatal_fr(r, "channel %i: consume", c->self); 3046 c->remote_window -= len; 3047 debug2("channel %d: sent ext data %zu", c->self, len); 3048 return 1; 3049 } 3050 3051 /* 3052 * If there is data to send to the connection, enqueue some of it now. 3053 * Returns non-zero if data was enqueued. 3054 */ 3055 int 3056 channel_output_poll(struct ssh *ssh) 3057 { 3058 struct ssh_channels *sc = ssh->chanctxt; 3059 Channel *c; 3060 u_int i; 3061 int ret = 0; 3062 3063 for (i = 0; i < sc->channels_alloc; i++) { 3064 c = sc->channels[i]; 3065 if (c == NULL) 3066 continue; 3067 3068 /* 3069 * We are only interested in channels that can have buffered 3070 * incoming data. 3071 */ 3072 if (c->type != SSH_CHANNEL_OPEN) 3073 continue; 3074 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3075 /* XXX is this true? */ 3076 debug3("channel %d: will not send data after close", 3077 c->self); 3078 continue; 3079 } 3080 3081 /* Get the amount of buffered data for this channel. */ 3082 if (c->istate == CHAN_INPUT_OPEN || 3083 c->istate == CHAN_INPUT_WAIT_DRAIN) 3084 ret |= channel_output_poll_input_open(ssh, c); 3085 /* Send extended data, i.e. stderr */ 3086 if (!(c->flags & CHAN_EOF_SENT) && 3087 c->extended_usage == CHAN_EXTENDED_READ) 3088 ret |= channel_output_poll_extended_read(ssh, c); 3089 } 3090 return ret; 3091 } 3092 3093 /* -- mux proxy support */ 3094 3095 /* 3096 * When multiplexing channel messages for mux clients we have to deal 3097 * with downstream messages from the mux client and upstream messages 3098 * from the ssh server: 3099 * 1) Handling downstream messages is straightforward and happens 3100 * in channel_proxy_downstream(): 3101 * - We forward all messages (mostly) unmodified to the server. 3102 * - However, in order to route messages from upstream to the correct 3103 * downstream client, we have to replace the channel IDs used by the 3104 * mux clients with a unique channel ID because the mux clients might 3105 * use conflicting channel IDs. 3106 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3107 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3108 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3109 * with the newly allocated channel ID. 3110 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3111 * channels and processed by channel_proxy_upstream(). The local channel ID 3112 * is then translated back to the original mux client ID. 3113 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3114 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3115 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3116 * downstream mux client are removed. 3117 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3118 * requires more work, because they are not addressed to a specific 3119 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3120 * out whether the request is addressed to the local client or a 3121 * specific downstream client based on the listen-address/port. 3122 * 6) Agent and X11-Forwarding have a similar problem and are currently 3123 * not supported as the matching session/channel cannot be identified 3124 * easily. 3125 */ 3126 3127 /* 3128 * receive packets from downstream mux clients: 3129 * channel callback fired on read from mux client, creates 3130 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3131 * on channel creation. 3132 */ 3133 int 3134 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3135 { 3136 Channel *c = NULL; 3137 struct sshbuf *original = NULL, *modified = NULL; 3138 const u_char *cp; 3139 char *ctype = NULL, *listen_host = NULL; 3140 u_char type; 3141 size_t have; 3142 int ret = -1, r; 3143 u_int id, remote_id, listen_port; 3144 3145 /* sshbuf_dump(downstream->input, stderr); */ 3146 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3147 != 0) { 3148 error_fr(r, "parse"); 3149 return -1; 3150 } 3151 if (have < 2) { 3152 error_f("short message"); 3153 return -1; 3154 } 3155 type = cp[1]; 3156 /* skip padlen + type */ 3157 cp += 2; 3158 have -= 2; 3159 if (ssh_packet_log_type(type)) 3160 debug3_f("channel %u: down->up: type %u", 3161 downstream->self, type); 3162 3163 switch (type) { 3164 case SSH2_MSG_CHANNEL_OPEN: 3165 if ((original = sshbuf_from(cp, have)) == NULL || 3166 (modified = sshbuf_new()) == NULL) { 3167 error_f("alloc"); 3168 goto out; 3169 } 3170 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3171 (r = sshbuf_get_u32(original, &id)) != 0) { 3172 error_fr(r, "parse"); 3173 goto out; 3174 } 3175 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3176 -1, -1, -1, 0, 0, 0, ctype, 1); 3177 c->mux_ctx = downstream; /* point to mux client */ 3178 c->mux_downstream_id = id; /* original downstream id */ 3179 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3180 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3181 (r = sshbuf_putb(modified, original)) != 0) { 3182 error_fr(r, "compose"); 3183 channel_free(ssh, c); 3184 goto out; 3185 } 3186 break; 3187 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3188 /* 3189 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3190 * need to parse 'remote_id' instead of 'ctype'. 3191 */ 3192 if ((original = sshbuf_from(cp, have)) == NULL || 3193 (modified = sshbuf_new()) == NULL) { 3194 error_f("alloc"); 3195 goto out; 3196 } 3197 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3198 (r = sshbuf_get_u32(original, &id)) != 0) { 3199 error_fr(r, "parse"); 3200 goto out; 3201 } 3202 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3203 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3204 c->mux_ctx = downstream; /* point to mux client */ 3205 c->mux_downstream_id = id; 3206 c->remote_id = remote_id; 3207 c->have_remote_id = 1; 3208 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3209 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3210 (r = sshbuf_putb(modified, original)) != 0) { 3211 error_fr(r, "compose"); 3212 channel_free(ssh, c); 3213 goto out; 3214 } 3215 break; 3216 case SSH2_MSG_GLOBAL_REQUEST: 3217 if ((original = sshbuf_from(cp, have)) == NULL) { 3218 error_f("alloc"); 3219 goto out; 3220 } 3221 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3222 error_fr(r, "parse"); 3223 goto out; 3224 } 3225 if (strcmp(ctype, "tcpip-forward") != 0) { 3226 error_f("unsupported request %s", ctype); 3227 goto out; 3228 } 3229 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3230 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3231 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3232 error_fr(r, "parse"); 3233 goto out; 3234 } 3235 if (listen_port > 65535) { 3236 error_f("tcpip-forward for %s: bad port %u", 3237 listen_host, listen_port); 3238 goto out; 3239 } 3240 /* Record that connection to this host/port is permitted. */ 3241 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", 3242 -1, listen_host, NULL, (int)listen_port, downstream); 3243 break; 3244 case SSH2_MSG_CHANNEL_CLOSE: 3245 if (have < 4) 3246 break; 3247 remote_id = PEEK_U32(cp); 3248 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3249 if (c->flags & CHAN_CLOSE_RCVD) 3250 channel_free(ssh, c); 3251 else 3252 c->flags |= CHAN_CLOSE_SENT; 3253 } 3254 break; 3255 } 3256 if (modified) { 3257 if ((r = sshpkt_start(ssh, type)) != 0 || 3258 (r = sshpkt_putb(ssh, modified)) != 0 || 3259 (r = sshpkt_send(ssh)) != 0) { 3260 error_fr(r, "send"); 3261 goto out; 3262 } 3263 } else { 3264 if ((r = sshpkt_start(ssh, type)) != 0 || 3265 (r = sshpkt_put(ssh, cp, have)) != 0 || 3266 (r = sshpkt_send(ssh)) != 0) { 3267 error_fr(r, "send"); 3268 goto out; 3269 } 3270 } 3271 ret = 0; 3272 out: 3273 free(ctype); 3274 free(listen_host); 3275 sshbuf_free(original); 3276 sshbuf_free(modified); 3277 return ret; 3278 } 3279 3280 /* 3281 * receive packets from upstream server and de-multiplex packets 3282 * to correct downstream: 3283 * implemented as a helper for channel input handlers, 3284 * replaces local (proxy) channel ID with downstream channel ID. 3285 */ 3286 int 3287 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3288 { 3289 struct sshbuf *b = NULL; 3290 Channel *downstream; 3291 const u_char *cp = NULL; 3292 size_t len; 3293 int r; 3294 3295 /* 3296 * When receiving packets from the peer we need to check whether we 3297 * need to forward the packets to the mux client. In this case we 3298 * restore the original channel id and keep track of CLOSE messages, 3299 * so we can cleanup the channel. 3300 */ 3301 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3302 return 0; 3303 if ((downstream = c->mux_ctx) == NULL) 3304 return 0; 3305 switch (type) { 3306 case SSH2_MSG_CHANNEL_CLOSE: 3307 case SSH2_MSG_CHANNEL_DATA: 3308 case SSH2_MSG_CHANNEL_EOF: 3309 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3310 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3311 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3312 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3313 case SSH2_MSG_CHANNEL_SUCCESS: 3314 case SSH2_MSG_CHANNEL_FAILURE: 3315 case SSH2_MSG_CHANNEL_REQUEST: 3316 break; 3317 default: 3318 debug2_f("channel %u: unsupported type %u", c->self, type); 3319 return 0; 3320 } 3321 if ((b = sshbuf_new()) == NULL) { 3322 error_f("alloc reply"); 3323 goto out; 3324 } 3325 /* get remaining payload (after id) */ 3326 cp = sshpkt_ptr(ssh, &len); 3327 if (cp == NULL) { 3328 error_f("no packet"); 3329 goto out; 3330 } 3331 /* translate id and send to muxclient */ 3332 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3333 (r = sshbuf_put_u8(b, type)) != 0 || 3334 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3335 (r = sshbuf_put(b, cp, len)) != 0 || 3336 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3337 error_fr(r, "compose muxclient"); 3338 goto out; 3339 } 3340 /* sshbuf_dump(b, stderr); */ 3341 if (ssh_packet_log_type(type)) 3342 debug3_f("channel %u: up->down: type %u", c->self, type); 3343 out: 3344 /* update state */ 3345 switch (type) { 3346 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3347 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3348 if (cp && len > 4) { 3349 c->remote_id = PEEK_U32(cp); 3350 c->have_remote_id = 1; 3351 } 3352 break; 3353 case SSH2_MSG_CHANNEL_CLOSE: 3354 if (c->flags & CHAN_CLOSE_SENT) 3355 channel_free(ssh, c); 3356 else 3357 c->flags |= CHAN_CLOSE_RCVD; 3358 break; 3359 } 3360 sshbuf_free(b); 3361 return 1; 3362 } 3363 3364 /* -- protocol input */ 3365 3366 /* Parse a channel ID from the current packet */ 3367 static int 3368 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3369 { 3370 u_int32_t id; 3371 int r; 3372 3373 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3374 error_r(r, "%s: parse id", where); 3375 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3376 } 3377 if (id > INT_MAX) { 3378 error_r(r, "%s: bad channel id %u", where, id); 3379 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3380 } 3381 return (int)id; 3382 } 3383 3384 /* Lookup a channel from an ID in the current packet */ 3385 static Channel * 3386 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3387 { 3388 int id = channel_parse_id(ssh, where, what); 3389 Channel *c; 3390 3391 if ((c = channel_lookup(ssh, id)) == NULL) { 3392 ssh_packet_disconnect(ssh, 3393 "%s packet referred to nonexistent channel %d", what, id); 3394 } 3395 return c; 3396 } 3397 3398 int 3399 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3400 { 3401 const u_char *data; 3402 size_t data_len, win_len; 3403 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3404 int r; 3405 3406 if (channel_proxy_upstream(c, type, seq, ssh)) 3407 return 0; 3408 3409 /* Ignore any data for non-open channels (might happen on close) */ 3410 if (c->type != SSH_CHANNEL_OPEN && 3411 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3412 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3413 c->type != SSH_CHANNEL_X11_OPEN) 3414 return 0; 3415 3416 /* Get the data. */ 3417 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3418 (r = sshpkt_get_end(ssh)) != 0) 3419 fatal_fr(r, "channel %i: get data", c->self); 3420 3421 win_len = data_len; 3422 if (c->datagram) 3423 win_len += 4; /* string length header */ 3424 3425 /* 3426 * The sending side reduces its window as it sends data, so we 3427 * must 'fake' consumption of the data in order to ensure that window 3428 * updates are sent back. Otherwise the connection might deadlock. 3429 */ 3430 if (c->ostate != CHAN_OUTPUT_OPEN) { 3431 c->local_window -= win_len; 3432 c->local_consumed += win_len; 3433 return 0; 3434 } 3435 3436 if (win_len > c->local_maxpacket) { 3437 logit("channel %d: rcvd big packet %zu, maxpack %u", 3438 c->self, win_len, c->local_maxpacket); 3439 return 0; 3440 } 3441 if (win_len > c->local_window) { 3442 c->local_window_exceeded += win_len - c->local_window; 3443 logit("channel %d: rcvd too much data %zu, win %u/%u " 3444 "(excess %u)", c->self, win_len, c->local_window, 3445 c->local_window_max, c->local_window_exceeded); 3446 c->local_window = 0; 3447 /* Allow 10% grace before bringing the hammer down */ 3448 if (c->local_window_exceeded > (c->local_window_max / 10)) { 3449 ssh_packet_disconnect(ssh, "channel %d: peer ignored " 3450 "channel window", c->self); 3451 } 3452 } else { 3453 c->local_window -= win_len; 3454 c->local_window_exceeded = 0; 3455 } 3456 3457 if (c->datagram) { 3458 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3459 fatal_fr(r, "channel %i: append datagram", c->self); 3460 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3461 fatal_fr(r, "channel %i: append data", c->self); 3462 3463 return 0; 3464 } 3465 3466 int 3467 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3468 { 3469 const u_char *data; 3470 size_t data_len; 3471 u_int32_t tcode; 3472 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3473 int r; 3474 3475 if (channel_proxy_upstream(c, type, seq, ssh)) 3476 return 0; 3477 if (c->type != SSH_CHANNEL_OPEN) { 3478 logit("channel %d: ext data for non open", c->self); 3479 return 0; 3480 } 3481 if (c->flags & CHAN_EOF_RCVD) { 3482 if (ssh->compat & SSH_BUG_EXTEOF) 3483 debug("channel %d: accepting ext data after eof", 3484 c->self); 3485 else 3486 ssh_packet_disconnect(ssh, "Received extended_data " 3487 "after EOF on channel %d.", c->self); 3488 } 3489 3490 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3491 error_fr(r, "parse tcode"); 3492 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3493 } 3494 if (c->efd == -1 || 3495 c->extended_usage != CHAN_EXTENDED_WRITE || 3496 tcode != SSH2_EXTENDED_DATA_STDERR) { 3497 logit("channel %d: bad ext data", c->self); 3498 return 0; 3499 } 3500 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3501 (r = sshpkt_get_end(ssh)) != 0) { 3502 error_fr(r, "parse data"); 3503 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3504 } 3505 3506 if (data_len > c->local_window) { 3507 logit("channel %d: rcvd too much extended_data %zu, win %u", 3508 c->self, data_len, c->local_window); 3509 return 0; 3510 } 3511 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3512 /* XXX sshpkt_getb? */ 3513 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3514 error_fr(r, "append"); 3515 c->local_window -= data_len; 3516 return 0; 3517 } 3518 3519 int 3520 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3521 { 3522 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3523 int r; 3524 3525 if ((r = sshpkt_get_end(ssh)) != 0) { 3526 error_fr(r, "parse data"); 3527 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3528 } 3529 3530 if (channel_proxy_upstream(c, type, seq, ssh)) 3531 return 0; 3532 chan_rcvd_ieof(ssh, c); 3533 3534 /* XXX force input close */ 3535 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3536 debug("channel %d: FORCE input drain", c->self); 3537 c->istate = CHAN_INPUT_WAIT_DRAIN; 3538 if (sshbuf_len(c->input) == 0) 3539 chan_ibuf_empty(ssh, c); 3540 } 3541 return 0; 3542 } 3543 3544 int 3545 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3546 { 3547 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3548 int r; 3549 3550 if (channel_proxy_upstream(c, type, seq, ssh)) 3551 return 0; 3552 if ((r = sshpkt_get_end(ssh)) != 0) { 3553 error_fr(r, "parse data"); 3554 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3555 } 3556 chan_rcvd_oclose(ssh, c); 3557 return 0; 3558 } 3559 3560 int 3561 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3562 { 3563 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3564 u_int32_t remote_window, remote_maxpacket; 3565 int r; 3566 3567 if (channel_proxy_upstream(c, type, seq, ssh)) 3568 return 0; 3569 if (c->type != SSH_CHANNEL_OPENING) 3570 ssh_packet_disconnect(ssh, "Received open confirmation for " 3571 "non-opening channel %d.", c->self); 3572 /* 3573 * Record the remote channel number and mark that the channel 3574 * is now open. 3575 */ 3576 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3577 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3578 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3579 (r = sshpkt_get_end(ssh)) != 0) { 3580 error_fr(r, "window/maxpacket"); 3581 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3582 } 3583 3584 c->have_remote_id = 1; 3585 c->remote_window = remote_window; 3586 c->remote_maxpacket = remote_maxpacket; 3587 c->type = SSH_CHANNEL_OPEN; 3588 if (c->open_confirm) { 3589 debug2_f("channel %d: callback start", c->self); 3590 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3591 debug2_f("channel %d: callback done", c->self); 3592 } 3593 channel_set_used_time(ssh, c); 3594 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3595 c->remote_window, c->remote_maxpacket); 3596 return 0; 3597 } 3598 3599 static char * 3600 reason2txt(int reason) 3601 { 3602 switch (reason) { 3603 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3604 return "administratively prohibited"; 3605 case SSH2_OPEN_CONNECT_FAILED: 3606 return "connect failed"; 3607 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3608 return "unknown channel type"; 3609 case SSH2_OPEN_RESOURCE_SHORTAGE: 3610 return "resource shortage"; 3611 } 3612 return "unknown reason"; 3613 } 3614 3615 int 3616 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3617 { 3618 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3619 u_int32_t reason; 3620 char *msg = NULL; 3621 int r; 3622 3623 if (channel_proxy_upstream(c, type, seq, ssh)) 3624 return 0; 3625 if (c->type != SSH_CHANNEL_OPENING) 3626 ssh_packet_disconnect(ssh, "Received open failure for " 3627 "non-opening channel %d.", c->self); 3628 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3629 error_fr(r, "parse reason"); 3630 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3631 } 3632 /* skip language */ 3633 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3634 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3635 (r = sshpkt_get_end(ssh)) != 0) { 3636 error_fr(r, "parse msg/lang"); 3637 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3638 } 3639 logit("channel %d: open failed: %s%s%s", c->self, 3640 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3641 free(msg); 3642 if (c->open_confirm) { 3643 debug2_f("channel %d: callback start", c->self); 3644 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3645 debug2_f("channel %d: callback done", c->self); 3646 } 3647 /* Schedule the channel for cleanup/deletion. */ 3648 chan_mark_dead(ssh, c); 3649 return 0; 3650 } 3651 3652 int 3653 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3654 { 3655 int id = channel_parse_id(ssh, __func__, "window adjust"); 3656 Channel *c; 3657 u_int32_t adjust; 3658 u_int new_rwin; 3659 int r; 3660 3661 if ((c = channel_lookup(ssh, id)) == NULL) { 3662 logit("Received window adjust for non-open channel %d.", id); 3663 return 0; 3664 } 3665 3666 if (channel_proxy_upstream(c, type, seq, ssh)) 3667 return 0; 3668 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3669 (r = sshpkt_get_end(ssh)) != 0) { 3670 error_fr(r, "parse adjust"); 3671 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3672 } 3673 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3674 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3675 fatal("channel %d: adjust %u overflows remote window %u", 3676 c->self, adjust, c->remote_window); 3677 } 3678 c->remote_window = new_rwin; 3679 return 0; 3680 } 3681 3682 int 3683 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3684 { 3685 int id = channel_parse_id(ssh, __func__, "status confirm"); 3686 Channel *c; 3687 struct channel_confirm *cc; 3688 3689 /* Reset keepalive timeout */ 3690 ssh_packet_set_alive_timeouts(ssh, 0); 3691 3692 debug2_f("type %d id %d", type, id); 3693 3694 if ((c = channel_lookup(ssh, id)) == NULL) { 3695 logit_f("%d: unknown", id); 3696 return 0; 3697 } 3698 if (channel_proxy_upstream(c, type, seq, ssh)) 3699 return 0; 3700 if (sshpkt_get_end(ssh) != 0) 3701 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3702 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3703 return 0; 3704 cc->cb(ssh, type, c, cc->ctx); 3705 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3706 freezero(cc, sizeof(*cc)); 3707 return 0; 3708 } 3709 3710 /* -- tcp forwarding */ 3711 3712 void 3713 channel_set_af(struct ssh *ssh, int af) 3714 { 3715 ssh->chanctxt->IPv4or6 = af; 3716 } 3717 3718 3719 /* 3720 * Determine whether or not a port forward listens to loopback, the 3721 * specified address or wildcard. On the client, a specified bind 3722 * address will always override gateway_ports. On the server, a 3723 * gateway_ports of 1 (``yes'') will override the client's specification 3724 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3725 * will bind to whatever address the client asked for. 3726 * 3727 * Special-case listen_addrs are: 3728 * 3729 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3730 * "" (empty string), "*" -> wildcard v4/v6 3731 * "localhost" -> loopback v4/v6 3732 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3733 */ 3734 static const char * 3735 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3736 int is_client, struct ForwardOptions *fwd_opts) 3737 { 3738 const char *addr = NULL; 3739 int wildcard = 0; 3740 3741 if (listen_addr == NULL) { 3742 /* No address specified: default to gateway_ports setting */ 3743 if (fwd_opts->gateway_ports) 3744 wildcard = 1; 3745 } else if (fwd_opts->gateway_ports || is_client) { 3746 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3747 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3748 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3749 (!is_client && fwd_opts->gateway_ports == 1)) { 3750 wildcard = 1; 3751 /* 3752 * Notify client if they requested a specific listen 3753 * address and it was overridden. 3754 */ 3755 if (*listen_addr != '\0' && 3756 strcmp(listen_addr, "0.0.0.0") != 0 && 3757 strcmp(listen_addr, "*") != 0) { 3758 ssh_packet_send_debug(ssh, 3759 "Forwarding listen address " 3760 "\"%s\" overridden by server " 3761 "GatewayPorts", listen_addr); 3762 } 3763 } else if (strcmp(listen_addr, "localhost") != 0 || 3764 strcmp(listen_addr, "127.0.0.1") == 0 || 3765 strcmp(listen_addr, "::1") == 0) { 3766 /* 3767 * Accept explicit localhost address when 3768 * GatewayPorts=yes. The "localhost" hostname is 3769 * deliberately skipped here so it will listen on all 3770 * available local address families. 3771 */ 3772 addr = listen_addr; 3773 } 3774 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3775 strcmp(listen_addr, "::1") == 0) { 3776 /* 3777 * If a specific IPv4/IPv6 localhost address has been 3778 * requested then accept it even if gateway_ports is in 3779 * effect. This allows the client to prefer IPv4 or IPv6. 3780 */ 3781 addr = listen_addr; 3782 } 3783 if (wildcardp != NULL) 3784 *wildcardp = wildcard; 3785 return addr; 3786 } 3787 3788 static int 3789 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3790 struct Forward *fwd, int *allocated_listen_port, 3791 struct ForwardOptions *fwd_opts) 3792 { 3793 Channel *c; 3794 int sock, r, success = 0, wildcard = 0, is_client; 3795 struct addrinfo hints, *ai, *aitop; 3796 const char *host, *addr; 3797 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3798 in_port_t *lport_p; 3799 3800 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3801 3802 if (is_client && fwd->connect_path != NULL) { 3803 host = fwd->connect_path; 3804 } else { 3805 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3806 fwd->listen_host : fwd->connect_host; 3807 if (host == NULL) { 3808 error("No forward host name."); 3809 return 0; 3810 } 3811 if (strlen(host) >= NI_MAXHOST) { 3812 error("Forward host name too long."); 3813 return 0; 3814 } 3815 } 3816 3817 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3818 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3819 is_client, fwd_opts); 3820 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3821 (addr == NULL) ? "NULL" : addr); 3822 3823 /* 3824 * getaddrinfo returns a loopback address if the hostname is 3825 * set to NULL and hints.ai_flags is not AI_PASSIVE 3826 */ 3827 memset(&hints, 0, sizeof(hints)); 3828 hints.ai_family = ssh->chanctxt->IPv4or6; 3829 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3830 hints.ai_socktype = SOCK_STREAM; 3831 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3832 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3833 if (addr == NULL) { 3834 /* This really shouldn't happen */ 3835 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3836 ssh_gai_strerror(r)); 3837 } else { 3838 error_f("getaddrinfo(%.64s): %s", addr, 3839 ssh_gai_strerror(r)); 3840 } 3841 return 0; 3842 } 3843 if (allocated_listen_port != NULL) 3844 *allocated_listen_port = 0; 3845 for (ai = aitop; ai; ai = ai->ai_next) { 3846 switch (ai->ai_family) { 3847 case AF_INET: 3848 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3849 sin_port; 3850 break; 3851 case AF_INET6: 3852 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3853 sin6_port; 3854 break; 3855 default: 3856 continue; 3857 } 3858 /* 3859 * If allocating a port for -R forwards, then use the 3860 * same port for all address families. 3861 */ 3862 if (type == SSH_CHANNEL_RPORT_LISTENER && 3863 fwd->listen_port == 0 && allocated_listen_port != NULL && 3864 *allocated_listen_port > 0) 3865 *lport_p = htons(*allocated_listen_port); 3866 3867 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3868 strport, sizeof(strport), 3869 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3870 error_f("getnameinfo failed"); 3871 continue; 3872 } 3873 /* Create a port to listen for the host. */ 3874 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3875 if (sock == -1) { 3876 /* this is no error since kernel may not support ipv6 */ 3877 verbose("socket [%s]:%s: %.100s", ntop, strport, 3878 strerror(errno)); 3879 continue; 3880 } 3881 3882 set_reuseaddr(sock); 3883 if (ai->ai_family == AF_INET6) 3884 sock_set_v6only(sock); 3885 3886 debug("Local forwarding listening on %s port %s.", 3887 ntop, strport); 3888 3889 /* Bind the socket to the address. */ 3890 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3891 /* 3892 * address can be in if use ipv6 address is 3893 * already bound 3894 */ 3895 if (!ai->ai_next) 3896 error("bind [%s]:%s: %.100s", 3897 ntop, strport, strerror(errno)); 3898 else 3899 verbose("bind [%s]:%s: %.100s", 3900 ntop, strport, strerror(errno)); 3901 3902 close(sock); 3903 continue; 3904 } 3905 /* Start listening for connections on the socket. */ 3906 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3907 error("listen [%s]:%s: %.100s", ntop, strport, 3908 strerror(errno)); 3909 close(sock); 3910 continue; 3911 } 3912 3913 /* 3914 * fwd->listen_port == 0 requests a dynamically allocated port - 3915 * record what we got. 3916 */ 3917 if (type == SSH_CHANNEL_RPORT_LISTENER && 3918 fwd->listen_port == 0 && 3919 allocated_listen_port != NULL && 3920 *allocated_listen_port == 0) { 3921 *allocated_listen_port = get_local_port(sock); 3922 debug("Allocated listen port %d", 3923 *allocated_listen_port); 3924 } 3925 3926 /* Allocate a channel number for the socket. */ 3927 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3928 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3929 0, "port listener", 1); 3930 c->path = xstrdup(host); 3931 c->host_port = fwd->connect_port; 3932 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3933 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3934 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3935 c->listening_port = *allocated_listen_port; 3936 else 3937 c->listening_port = fwd->listen_port; 3938 success = 1; 3939 } 3940 if (success == 0) 3941 error_f("cannot listen to port: %d", fwd->listen_port); 3942 freeaddrinfo(aitop); 3943 return success; 3944 } 3945 3946 static int 3947 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3948 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3949 { 3950 struct sockaddr_un sunaddr; 3951 const char *path; 3952 Channel *c; 3953 int port, sock; 3954 mode_t omask; 3955 3956 switch (type) { 3957 case SSH_CHANNEL_UNIX_LISTENER: 3958 if (fwd->connect_path != NULL) { 3959 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3960 error("Local connecting path too long: %s", 3961 fwd->connect_path); 3962 return 0; 3963 } 3964 path = fwd->connect_path; 3965 port = PORT_STREAMLOCAL; 3966 } else { 3967 if (fwd->connect_host == NULL) { 3968 error("No forward host name."); 3969 return 0; 3970 } 3971 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3972 error("Forward host name too long."); 3973 return 0; 3974 } 3975 path = fwd->connect_host; 3976 port = fwd->connect_port; 3977 } 3978 break; 3979 case SSH_CHANNEL_RUNIX_LISTENER: 3980 path = fwd->listen_path; 3981 port = PORT_STREAMLOCAL; 3982 break; 3983 default: 3984 error_f("unexpected channel type %d", type); 3985 return 0; 3986 } 3987 3988 if (fwd->listen_path == NULL) { 3989 error("No forward path name."); 3990 return 0; 3991 } 3992 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3993 error("Local listening path too long: %s", fwd->listen_path); 3994 return 0; 3995 } 3996 3997 debug3_f("type %d path %s", type, fwd->listen_path); 3998 3999 /* Start a Unix domain listener. */ 4000 omask = umask(fwd_opts->streamlocal_bind_mask); 4001 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 4002 fwd_opts->streamlocal_bind_unlink); 4003 umask(omask); 4004 if (sock < 0) 4005 return 0; 4006 4007 debug("Local forwarding listening on path %s.", fwd->listen_path); 4008 4009 /* Allocate a channel number for the socket. */ 4010 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 4011 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 4012 0, "unix listener", 1); 4013 c->path = xstrdup(path); 4014 c->host_port = port; 4015 c->listening_port = PORT_STREAMLOCAL; 4016 c->listening_addr = xstrdup(fwd->listen_path); 4017 return 1; 4018 } 4019 4020 static int 4021 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 4022 const char *host, u_short port) 4023 { 4024 u_int i; 4025 int found = 0; 4026 4027 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4028 Channel *c = ssh->chanctxt->channels[i]; 4029 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 4030 continue; 4031 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 4032 debug2_f("close channel %d", i); 4033 channel_free(ssh, c); 4034 found = 1; 4035 } 4036 } 4037 4038 return found; 4039 } 4040 4041 static int 4042 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 4043 { 4044 u_int i; 4045 int found = 0; 4046 4047 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4048 Channel *c = ssh->chanctxt->channels[i]; 4049 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 4050 continue; 4051 if (c->path == NULL) 4052 continue; 4053 if (strcmp(c->path, path) == 0) { 4054 debug2_f("close channel %d", i); 4055 channel_free(ssh, c); 4056 found = 1; 4057 } 4058 } 4059 4060 return found; 4061 } 4062 4063 int 4064 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4065 { 4066 if (fwd->listen_path != NULL) { 4067 return channel_cancel_rport_listener_streamlocal(ssh, 4068 fwd->listen_path); 4069 } else { 4070 return channel_cancel_rport_listener_tcpip(ssh, 4071 fwd->listen_host, fwd->listen_port); 4072 } 4073 } 4074 4075 static int 4076 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4077 const char *lhost, u_short lport, int cport, 4078 struct ForwardOptions *fwd_opts) 4079 { 4080 u_int i; 4081 int found = 0; 4082 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4083 4084 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4085 Channel *c = ssh->chanctxt->channels[i]; 4086 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4087 continue; 4088 if (c->listening_port != lport) 4089 continue; 4090 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4091 /* skip dynamic forwardings */ 4092 if (c->host_port == 0) 4093 continue; 4094 } else { 4095 if (c->host_port != cport) 4096 continue; 4097 } 4098 if ((c->listening_addr == NULL && addr != NULL) || 4099 (c->listening_addr != NULL && addr == NULL)) 4100 continue; 4101 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4102 debug2_f("close channel %d", i); 4103 channel_free(ssh, c); 4104 found = 1; 4105 } 4106 } 4107 4108 return found; 4109 } 4110 4111 static int 4112 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4113 { 4114 u_int i; 4115 int found = 0; 4116 4117 if (path == NULL) { 4118 error_f("no path specified."); 4119 return 0; 4120 } 4121 4122 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4123 Channel *c = ssh->chanctxt->channels[i]; 4124 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4125 continue; 4126 if (c->listening_addr == NULL) 4127 continue; 4128 if (strcmp(c->listening_addr, path) == 0) { 4129 debug2_f("close channel %d", i); 4130 channel_free(ssh, c); 4131 found = 1; 4132 } 4133 } 4134 4135 return found; 4136 } 4137 4138 int 4139 channel_cancel_lport_listener(struct ssh *ssh, 4140 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4141 { 4142 if (fwd->listen_path != NULL) { 4143 return channel_cancel_lport_listener_streamlocal(ssh, 4144 fwd->listen_path); 4145 } else { 4146 return channel_cancel_lport_listener_tcpip(ssh, 4147 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4148 } 4149 } 4150 4151 /* protocol local port fwd, used by ssh */ 4152 int 4153 channel_setup_local_fwd_listener(struct ssh *ssh, 4154 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4155 { 4156 if (fwd->listen_path != NULL) { 4157 return channel_setup_fwd_listener_streamlocal(ssh, 4158 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4159 } else { 4160 return channel_setup_fwd_listener_tcpip(ssh, 4161 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4162 } 4163 } 4164 4165 /* Matches a remote forwarding permission against a requested forwarding */ 4166 static int 4167 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4168 { 4169 int ret; 4170 char *lhost; 4171 4172 /* XXX add ACLs for streamlocal */ 4173 if (fwd->listen_path != NULL) 4174 return 1; 4175 4176 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4177 return 0; 4178 4179 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4180 allowed_open->listen_port != fwd->listen_port) 4181 return 0; 4182 4183 /* Match hostnames case-insensitively */ 4184 lhost = xstrdup(fwd->listen_host); 4185 lowercase(lhost); 4186 ret = match_pattern(lhost, allowed_open->listen_host); 4187 free(lhost); 4188 4189 return ret; 4190 } 4191 4192 /* Checks whether a requested remote forwarding is permitted */ 4193 static int 4194 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4195 { 4196 struct ssh_channels *sc = ssh->chanctxt; 4197 struct permission_set *pset = &sc->remote_perms; 4198 u_int i, permit, permit_adm = 1; 4199 struct permission *perm; 4200 4201 /* XXX apply GatewayPorts override before checking? */ 4202 4203 permit = pset->all_permitted; 4204 if (!permit) { 4205 for (i = 0; i < pset->num_permitted_user; i++) { 4206 perm = &pset->permitted_user[i]; 4207 if (remote_open_match(perm, fwd)) { 4208 permit = 1; 4209 break; 4210 } 4211 } 4212 } 4213 4214 if (pset->num_permitted_admin > 0) { 4215 permit_adm = 0; 4216 for (i = 0; i < pset->num_permitted_admin; i++) { 4217 perm = &pset->permitted_admin[i]; 4218 if (remote_open_match(perm, fwd)) { 4219 permit_adm = 1; 4220 break; 4221 } 4222 } 4223 } 4224 4225 return permit && permit_adm; 4226 } 4227 4228 /* protocol v2 remote port fwd, used by sshd */ 4229 int 4230 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4231 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4232 { 4233 if (!check_rfwd_permission(ssh, fwd)) { 4234 ssh_packet_send_debug(ssh, "port forwarding refused"); 4235 if (fwd->listen_path != NULL) 4236 /* XXX always allowed, see remote_open_match() */ 4237 logit("Received request from %.100s port %d to " 4238 "remote forward to path \"%.100s\", " 4239 "but the request was denied.", 4240 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4241 fwd->listen_path); 4242 else if(fwd->listen_host != NULL) 4243 logit("Received request from %.100s port %d to " 4244 "remote forward to host %.100s port %d, " 4245 "but the request was denied.", 4246 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4247 fwd->listen_host, fwd->listen_port ); 4248 else 4249 logit("Received request from %.100s port %d to remote " 4250 "forward, but the request was denied.", 4251 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4252 return 0; 4253 } 4254 if (fwd->listen_path != NULL) { 4255 return channel_setup_fwd_listener_streamlocal(ssh, 4256 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4257 } else { 4258 return channel_setup_fwd_listener_tcpip(ssh, 4259 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4260 fwd_opts); 4261 } 4262 } 4263 4264 /* 4265 * Translate the requested rfwd listen host to something usable for 4266 * this server. 4267 */ 4268 static const char * 4269 channel_rfwd_bind_host(const char *listen_host) 4270 { 4271 if (listen_host == NULL) { 4272 return "localhost"; 4273 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4274 return ""; 4275 } else 4276 return listen_host; 4277 } 4278 4279 /* 4280 * Initiate forwarding of connections to port "port" on remote host through 4281 * the secure channel to host:port from local side. 4282 * Returns handle (index) for updating the dynamic listen port with 4283 * channel_update_permission(). 4284 */ 4285 int 4286 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4287 { 4288 int r, success = 0, idx = -1; 4289 const char *host_to_connect, *listen_host, *listen_path; 4290 int port_to_connect, listen_port; 4291 4292 /* Send the forward request to the remote side. */ 4293 if (fwd->listen_path != NULL) { 4294 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4295 (r = sshpkt_put_cstring(ssh, 4296 "streamlocal-forward@openssh.com")) != 0 || 4297 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4298 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4299 (r = sshpkt_send(ssh)) != 0 || 4300 (r = ssh_packet_write_wait(ssh)) != 0) 4301 fatal_fr(r, "request streamlocal"); 4302 } else { 4303 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4304 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4305 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4306 (r = sshpkt_put_cstring(ssh, 4307 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4308 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4309 (r = sshpkt_send(ssh)) != 0 || 4310 (r = ssh_packet_write_wait(ssh)) != 0) 4311 fatal_fr(r, "request tcpip-forward"); 4312 } 4313 /* Assume that server accepts the request */ 4314 success = 1; 4315 if (success) { 4316 /* Record that connection to this host/port is permitted. */ 4317 host_to_connect = listen_host = listen_path = NULL; 4318 port_to_connect = listen_port = 0; 4319 if (fwd->connect_path != NULL) { 4320 host_to_connect = fwd->connect_path; 4321 port_to_connect = PORT_STREAMLOCAL; 4322 } else { 4323 host_to_connect = fwd->connect_host; 4324 port_to_connect = fwd->connect_port; 4325 } 4326 if (fwd->listen_path != NULL) { 4327 listen_path = fwd->listen_path; 4328 listen_port = PORT_STREAMLOCAL; 4329 } else { 4330 listen_host = fwd->listen_host; 4331 listen_port = fwd->listen_port; 4332 } 4333 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4334 host_to_connect, port_to_connect, 4335 listen_host, listen_path, listen_port, NULL); 4336 } 4337 return idx; 4338 } 4339 4340 static int 4341 open_match(struct permission *allowed_open, const char *requestedhost, 4342 int requestedport) 4343 { 4344 if (allowed_open->host_to_connect == NULL) 4345 return 0; 4346 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4347 allowed_open->port_to_connect != requestedport) 4348 return 0; 4349 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4350 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4351 return 0; 4352 return 1; 4353 } 4354 4355 /* 4356 * Note that in the listen host/port case 4357 * we don't support FWD_PERMIT_ANY_PORT and 4358 * need to translate between the configured-host (listen_host) 4359 * and what we've sent to the remote server (channel_rfwd_bind_host) 4360 */ 4361 static int 4362 open_listen_match_tcpip(struct permission *allowed_open, 4363 const char *requestedhost, u_short requestedport, int translate) 4364 { 4365 const char *allowed_host; 4366 4367 if (allowed_open->host_to_connect == NULL) 4368 return 0; 4369 if (allowed_open->listen_port != requestedport) 4370 return 0; 4371 if (!translate && allowed_open->listen_host == NULL && 4372 requestedhost == NULL) 4373 return 1; 4374 allowed_host = translate ? 4375 channel_rfwd_bind_host(allowed_open->listen_host) : 4376 allowed_open->listen_host; 4377 if (allowed_host == NULL || requestedhost == NULL || 4378 strcmp(allowed_host, requestedhost) != 0) 4379 return 0; 4380 return 1; 4381 } 4382 4383 static int 4384 open_listen_match_streamlocal(struct permission *allowed_open, 4385 const char *requestedpath) 4386 { 4387 if (allowed_open->host_to_connect == NULL) 4388 return 0; 4389 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4390 return 0; 4391 if (allowed_open->listen_path == NULL || 4392 strcmp(allowed_open->listen_path, requestedpath) != 0) 4393 return 0; 4394 return 1; 4395 } 4396 4397 /* 4398 * Request cancellation of remote forwarding of connection host:port from 4399 * local side. 4400 */ 4401 static int 4402 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4403 const char *host, u_short port) 4404 { 4405 struct ssh_channels *sc = ssh->chanctxt; 4406 struct permission_set *pset = &sc->local_perms; 4407 int r; 4408 u_int i; 4409 struct permission *perm = NULL; 4410 4411 for (i = 0; i < pset->num_permitted_user; i++) { 4412 perm = &pset->permitted_user[i]; 4413 if (open_listen_match_tcpip(perm, host, port, 0)) 4414 break; 4415 perm = NULL; 4416 } 4417 if (perm == NULL) { 4418 debug_f("requested forward not found"); 4419 return -1; 4420 } 4421 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4422 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4423 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4424 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4425 (r = sshpkt_put_u32(ssh, port)) != 0 || 4426 (r = sshpkt_send(ssh)) != 0) 4427 fatal_fr(r, "send cancel"); 4428 4429 fwd_perm_clear(perm); /* unregister */ 4430 4431 return 0; 4432 } 4433 4434 /* 4435 * Request cancellation of remote forwarding of Unix domain socket 4436 * path from local side. 4437 */ 4438 static int 4439 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4440 { 4441 struct ssh_channels *sc = ssh->chanctxt; 4442 struct permission_set *pset = &sc->local_perms; 4443 int r; 4444 u_int i; 4445 struct permission *perm = NULL; 4446 4447 for (i = 0; i < pset->num_permitted_user; i++) { 4448 perm = &pset->permitted_user[i]; 4449 if (open_listen_match_streamlocal(perm, path)) 4450 break; 4451 perm = NULL; 4452 } 4453 if (perm == NULL) { 4454 debug_f("requested forward not found"); 4455 return -1; 4456 } 4457 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4458 (r = sshpkt_put_cstring(ssh, 4459 "cancel-streamlocal-forward@openssh.com")) != 0 || 4460 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4461 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4462 (r = sshpkt_send(ssh)) != 0) 4463 fatal_fr(r, "send cancel"); 4464 4465 fwd_perm_clear(perm); /* unregister */ 4466 4467 return 0; 4468 } 4469 4470 /* 4471 * Request cancellation of remote forwarding of a connection from local side. 4472 */ 4473 int 4474 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4475 { 4476 if (fwd->listen_path != NULL) { 4477 return channel_request_rforward_cancel_streamlocal(ssh, 4478 fwd->listen_path); 4479 } else { 4480 return channel_request_rforward_cancel_tcpip(ssh, 4481 fwd->listen_host, 4482 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4483 } 4484 } 4485 4486 /* 4487 * Permits opening to any host/port if permitted_user[] is empty. This is 4488 * usually called by the server, because the user could connect to any port 4489 * anyway, and the server has no way to know but to trust the client anyway. 4490 */ 4491 void 4492 channel_permit_all(struct ssh *ssh, int where) 4493 { 4494 struct permission_set *pset = permission_set_get(ssh, where); 4495 4496 if (pset->num_permitted_user == 0) 4497 pset->all_permitted = 1; 4498 } 4499 4500 /* 4501 * Permit the specified host/port for forwarding. 4502 */ 4503 void 4504 channel_add_permission(struct ssh *ssh, int who, int where, 4505 char *host, int port) 4506 { 4507 int local = where == FORWARD_LOCAL; 4508 struct permission_set *pset = permission_set_get(ssh, where); 4509 4510 debug("allow %s forwarding to host %s port %d", 4511 fwd_ident(who, where), host, port); 4512 /* 4513 * Remote forwards set listen_host/port, local forwards set 4514 * host/port_to_connect. 4515 */ 4516 permission_set_add(ssh, who, where, 4517 local ? host : 0, local ? port : 0, 4518 local ? NULL : host, NULL, local ? 0 : port, NULL); 4519 pset->all_permitted = 0; 4520 } 4521 4522 /* 4523 * Administratively disable forwarding. 4524 */ 4525 void 4526 channel_disable_admin(struct ssh *ssh, int where) 4527 { 4528 channel_clear_permission(ssh, FORWARD_ADM, where); 4529 permission_set_add(ssh, FORWARD_ADM, where, 4530 NULL, 0, NULL, NULL, 0, NULL); 4531 } 4532 4533 /* 4534 * Clear a list of permitted opens. 4535 */ 4536 void 4537 channel_clear_permission(struct ssh *ssh, int who, int where) 4538 { 4539 struct permission **permp; 4540 u_int *npermp; 4541 4542 permission_set_get_array(ssh, who, where, &permp, &npermp); 4543 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4544 *npermp = 0; 4545 } 4546 4547 /* 4548 * Update the listen port for a dynamic remote forward, after 4549 * the actual 'newport' has been allocated. If 'newport' < 0 is 4550 * passed then they entry will be invalidated. 4551 */ 4552 void 4553 channel_update_permission(struct ssh *ssh, int idx, int newport) 4554 { 4555 struct permission_set *pset = &ssh->chanctxt->local_perms; 4556 4557 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4558 debug_f("index out of range: %d num_permitted_user %d", 4559 idx, pset->num_permitted_user); 4560 return; 4561 } 4562 debug("%s allowed port %d for forwarding to host %s port %d", 4563 newport > 0 ? "Updating" : "Removing", 4564 newport, 4565 pset->permitted_user[idx].host_to_connect, 4566 pset->permitted_user[idx].port_to_connect); 4567 if (newport <= 0) 4568 fwd_perm_clear(&pset->permitted_user[idx]); 4569 else { 4570 pset->permitted_user[idx].listen_port = 4571 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4572 } 4573 } 4574 4575 /* Try to start non-blocking connect to next host in cctx list */ 4576 static int 4577 connect_next(struct channel_connect *cctx) 4578 { 4579 int sock, saved_errno; 4580 struct sockaddr_un *sunaddr; 4581 char ntop[NI_MAXHOST]; 4582 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4583 4584 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4585 switch (cctx->ai->ai_family) { 4586 case AF_UNIX: 4587 /* unix:pathname instead of host:port */ 4588 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4589 strlcpy(ntop, "unix", sizeof(ntop)); 4590 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4591 break; 4592 case AF_INET: 4593 case AF_INET6: 4594 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4595 ntop, sizeof(ntop), strport, sizeof(strport), 4596 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4597 error_f("getnameinfo failed"); 4598 continue; 4599 } 4600 break; 4601 default: 4602 continue; 4603 } 4604 debug_f("start for host %.100s ([%.100s]:%s)", 4605 cctx->host, ntop, strport); 4606 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4607 cctx->ai->ai_protocol)) == -1) { 4608 if (cctx->ai->ai_next == NULL) 4609 error("socket: %.100s", strerror(errno)); 4610 else 4611 verbose("socket: %.100s", strerror(errno)); 4612 continue; 4613 } 4614 if (set_nonblock(sock) == -1) 4615 fatal_f("set_nonblock(%d)", sock); 4616 if (connect(sock, cctx->ai->ai_addr, 4617 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4618 debug_f("host %.100s ([%.100s]:%s): %.100s", 4619 cctx->host, ntop, strport, strerror(errno)); 4620 saved_errno = errno; 4621 close(sock); 4622 errno = saved_errno; 4623 continue; /* fail -- try next */ 4624 } 4625 if (cctx->ai->ai_family != AF_UNIX) 4626 set_nodelay(sock); 4627 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4628 cctx->host, ntop, strport, sock); 4629 cctx->ai = cctx->ai->ai_next; 4630 return sock; 4631 } 4632 return -1; 4633 } 4634 4635 static void 4636 channel_connect_ctx_free(struct channel_connect *cctx) 4637 { 4638 free(cctx->host); 4639 if (cctx->aitop) { 4640 if (cctx->aitop->ai_family == AF_UNIX) 4641 free(cctx->aitop); 4642 else 4643 freeaddrinfo(cctx->aitop); 4644 } 4645 memset(cctx, 0, sizeof(*cctx)); 4646 } 4647 4648 /* 4649 * Return connecting socket to remote host:port or local socket path, 4650 * passing back the failure reason if appropriate. 4651 */ 4652 static int 4653 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4654 char *ctype, char *rname, struct channel_connect *cctx, 4655 int *reason, const char **errmsg) 4656 { 4657 struct addrinfo hints; 4658 int gaierr; 4659 int sock = -1; 4660 char strport[NI_MAXSERV]; 4661 4662 if (port == PORT_STREAMLOCAL) { 4663 struct sockaddr_un *sunaddr; 4664 struct addrinfo *ai; 4665 4666 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4667 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4668 return -1; 4669 } 4670 4671 /* 4672 * Fake up a struct addrinfo for AF_UNIX connections. 4673 * channel_connect_ctx_free() must check ai_family 4674 * and use free() not freeaddirinfo() for AF_UNIX. 4675 */ 4676 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4677 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4678 ai->ai_addr = (struct sockaddr *)(ai + 1); 4679 ai->ai_addrlen = sizeof(*sunaddr); 4680 ai->ai_family = AF_UNIX; 4681 ai->ai_socktype = socktype; 4682 ai->ai_protocol = PF_UNSPEC; 4683 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4684 sunaddr->sun_family = AF_UNIX; 4685 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4686 cctx->aitop = ai; 4687 } else { 4688 memset(&hints, 0, sizeof(hints)); 4689 hints.ai_family = ssh->chanctxt->IPv4or6; 4690 hints.ai_socktype = socktype; 4691 snprintf(strport, sizeof strport, "%d", port); 4692 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4693 != 0) { 4694 if (errmsg != NULL) 4695 *errmsg = ssh_gai_strerror(gaierr); 4696 if (reason != NULL) 4697 *reason = SSH2_OPEN_CONNECT_FAILED; 4698 error("connect_to %.100s: unknown host (%s)", name, 4699 ssh_gai_strerror(gaierr)); 4700 return -1; 4701 } 4702 } 4703 4704 cctx->host = xstrdup(name); 4705 cctx->port = port; 4706 cctx->ai = cctx->aitop; 4707 4708 if ((sock = connect_next(cctx)) == -1) { 4709 error("connect to %.100s port %d failed: %s", 4710 name, port, strerror(errno)); 4711 return -1; 4712 } 4713 4714 return sock; 4715 } 4716 4717 /* Return CONNECTING channel to remote host:port or local socket path */ 4718 static Channel * 4719 connect_to(struct ssh *ssh, const char *host, int port, 4720 char *ctype, char *rname) 4721 { 4722 struct channel_connect cctx; 4723 Channel *c; 4724 int sock; 4725 4726 memset(&cctx, 0, sizeof(cctx)); 4727 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4728 &cctx, NULL, NULL); 4729 if (sock == -1) { 4730 channel_connect_ctx_free(&cctx); 4731 return NULL; 4732 } 4733 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4734 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4735 c->host_port = port; 4736 c->path = xstrdup(host); 4737 c->connect_ctx = cctx; 4738 4739 return c; 4740 } 4741 4742 /* 4743 * returns either the newly connected channel or the downstream channel 4744 * that needs to deal with this connection. 4745 */ 4746 Channel * 4747 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4748 u_short listen_port, char *ctype, char *rname) 4749 { 4750 struct ssh_channels *sc = ssh->chanctxt; 4751 struct permission_set *pset = &sc->local_perms; 4752 u_int i; 4753 struct permission *perm; 4754 4755 for (i = 0; i < pset->num_permitted_user; i++) { 4756 perm = &pset->permitted_user[i]; 4757 if (open_listen_match_tcpip(perm, 4758 listen_host, listen_port, 1)) { 4759 if (perm->downstream) 4760 return perm->downstream; 4761 if (perm->port_to_connect == 0) 4762 return rdynamic_connect_prepare(ssh, 4763 ctype, rname); 4764 return connect_to(ssh, 4765 perm->host_to_connect, perm->port_to_connect, 4766 ctype, rname); 4767 } 4768 } 4769 error("WARNING: Server requests forwarding for unknown listen_port %d", 4770 listen_port); 4771 return NULL; 4772 } 4773 4774 Channel * 4775 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4776 char *ctype, char *rname) 4777 { 4778 struct ssh_channels *sc = ssh->chanctxt; 4779 struct permission_set *pset = &sc->local_perms; 4780 u_int i; 4781 struct permission *perm; 4782 4783 for (i = 0; i < pset->num_permitted_user; i++) { 4784 perm = &pset->permitted_user[i]; 4785 if (open_listen_match_streamlocal(perm, path)) { 4786 return connect_to(ssh, 4787 perm->host_to_connect, perm->port_to_connect, 4788 ctype, rname); 4789 } 4790 } 4791 error("WARNING: Server requests forwarding for unknown path %.100s", 4792 path); 4793 return NULL; 4794 } 4795 4796 /* Check if connecting to that port is permitted and connect. */ 4797 Channel * 4798 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4799 char *ctype, char *rname, int *reason, const char **errmsg) 4800 { 4801 struct ssh_channels *sc = ssh->chanctxt; 4802 struct permission_set *pset = &sc->local_perms; 4803 struct channel_connect cctx; 4804 Channel *c; 4805 u_int i, permit, permit_adm = 1; 4806 int sock; 4807 struct permission *perm; 4808 4809 permit = pset->all_permitted; 4810 if (!permit) { 4811 for (i = 0; i < pset->num_permitted_user; i++) { 4812 perm = &pset->permitted_user[i]; 4813 if (open_match(perm, host, port)) { 4814 permit = 1; 4815 break; 4816 } 4817 } 4818 } 4819 4820 if (pset->num_permitted_admin > 0) { 4821 permit_adm = 0; 4822 for (i = 0; i < pset->num_permitted_admin; i++) { 4823 perm = &pset->permitted_admin[i]; 4824 if (open_match(perm, host, port)) { 4825 permit_adm = 1; 4826 break; 4827 } 4828 } 4829 } 4830 4831 if (!permit || !permit_adm) { 4832 logit("Received request from %.100s port %d to connect to " 4833 "host %.100s port %d, but the request was denied.", 4834 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4835 if (reason != NULL) 4836 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4837 return NULL; 4838 } 4839 4840 memset(&cctx, 0, sizeof(cctx)); 4841 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4842 &cctx, reason, errmsg); 4843 if (sock == -1) { 4844 channel_connect_ctx_free(&cctx); 4845 return NULL; 4846 } 4847 4848 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4849 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4850 c->host_port = port; 4851 c->path = xstrdup(host); 4852 c->connect_ctx = cctx; 4853 4854 return c; 4855 } 4856 4857 /* Check if connecting to that path is permitted and connect. */ 4858 Channel * 4859 channel_connect_to_path(struct ssh *ssh, const char *path, 4860 char *ctype, char *rname) 4861 { 4862 struct ssh_channels *sc = ssh->chanctxt; 4863 struct permission_set *pset = &sc->local_perms; 4864 u_int i, permit, permit_adm = 1; 4865 struct permission *perm; 4866 4867 permit = pset->all_permitted; 4868 if (!permit) { 4869 for (i = 0; i < pset->num_permitted_user; i++) { 4870 perm = &pset->permitted_user[i]; 4871 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4872 permit = 1; 4873 break; 4874 } 4875 } 4876 } 4877 4878 if (pset->num_permitted_admin > 0) { 4879 permit_adm = 0; 4880 for (i = 0; i < pset->num_permitted_admin; i++) { 4881 perm = &pset->permitted_admin[i]; 4882 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4883 permit_adm = 1; 4884 break; 4885 } 4886 } 4887 } 4888 4889 if (!permit || !permit_adm) { 4890 logit("Received request to connect to path %.100s, " 4891 "but the request was denied.", path); 4892 return NULL; 4893 } 4894 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4895 } 4896 4897 void 4898 channel_send_window_changes(struct ssh *ssh) 4899 { 4900 struct ssh_channels *sc = ssh->chanctxt; 4901 struct winsize ws; 4902 int r; 4903 u_int i; 4904 4905 for (i = 0; i < sc->channels_alloc; i++) { 4906 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4907 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4908 continue; 4909 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4910 continue; 4911 channel_request_start(ssh, i, "window-change", 0); 4912 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4913 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4914 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4915 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4916 (r = sshpkt_send(ssh)) != 0) 4917 fatal_fr(r, "channel %u; send window-change", i); 4918 } 4919 } 4920 4921 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4922 static Channel * 4923 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4924 { 4925 Channel *c; 4926 int r; 4927 4928 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4929 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4930 c->host_port = 0; 4931 c->path = NULL; 4932 4933 /* 4934 * We need to open the channel before we have a FD, 4935 * so that we can get SOCKS header from peer. 4936 */ 4937 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4938 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4939 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4940 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4941 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4942 fatal_fr(r, "channel %i; confirm", c->self); 4943 return c; 4944 } 4945 4946 /* Return CONNECTING socket to remote host:port or local socket path */ 4947 static int 4948 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4949 { 4950 struct ssh_channels *sc = ssh->chanctxt; 4951 struct permission_set *pset = &sc->local_perms; 4952 struct permission *perm; 4953 struct channel_connect cctx; 4954 u_int i, permit_adm = 1; 4955 int sock; 4956 4957 if (pset->num_permitted_admin > 0) { 4958 permit_adm = 0; 4959 for (i = 0; i < pset->num_permitted_admin; i++) { 4960 perm = &pset->permitted_admin[i]; 4961 if (open_match(perm, c->path, c->host_port)) { 4962 permit_adm = 1; 4963 break; 4964 } 4965 } 4966 } 4967 if (!permit_adm) { 4968 debug_f("requested forward not permitted"); 4969 return -1; 4970 } 4971 4972 memset(&cctx, 0, sizeof(cctx)); 4973 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4974 NULL, &cctx, NULL, NULL); 4975 if (sock == -1) 4976 channel_connect_ctx_free(&cctx); 4977 else { 4978 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4979 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4980 c->connect_ctx = cctx; 4981 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4982 } 4983 return sock; 4984 } 4985 4986 /* -- X11 forwarding */ 4987 4988 /* 4989 * Creates an internet domain socket for listening for X11 connections. 4990 * Returns 0 and a suitable display number for the DISPLAY variable 4991 * stored in display_numberp , or -1 if an error occurs. 4992 */ 4993 int 4994 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4995 int x11_use_localhost, int single_connection, 4996 u_int *display_numberp, int **chanids) 4997 { 4998 Channel *nc = NULL; 4999 int display_number, sock; 5000 u_short port; 5001 struct addrinfo hints, *ai, *aitop; 5002 char strport[NI_MAXSERV]; 5003 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 5004 5005 if (chanids == NULL) 5006 return -1; 5007 5008 for (display_number = x11_display_offset; 5009 display_number < MAX_DISPLAYS; 5010 display_number++) { 5011 port = 6000 + display_number; 5012 memset(&hints, 0, sizeof(hints)); 5013 hints.ai_family = ssh->chanctxt->IPv4or6; 5014 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 5015 hints.ai_socktype = SOCK_STREAM; 5016 snprintf(strport, sizeof strport, "%d", port); 5017 if ((gaierr = getaddrinfo(NULL, strport, 5018 &hints, &aitop)) != 0) { 5019 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 5020 return -1; 5021 } 5022 for (ai = aitop; ai; ai = ai->ai_next) { 5023 if (ai->ai_family != AF_INET && 5024 ai->ai_family != AF_INET6) 5025 continue; 5026 sock = socket(ai->ai_family, ai->ai_socktype, 5027 ai->ai_protocol); 5028 if (sock == -1) { 5029 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 5030 #ifdef EPFNOSUPPORT 5031 && (errno != EPFNOSUPPORT) 5032 #endif 5033 ) { 5034 error("socket: %.100s", strerror(errno)); 5035 freeaddrinfo(aitop); 5036 return -1; 5037 } else { 5038 debug("x11_create_display_inet: Socket family %d not supported", 5039 ai->ai_family); 5040 continue; 5041 } 5042 } 5043 if (ai->ai_family == AF_INET6) 5044 sock_set_v6only(sock); 5045 if (x11_use_localhost) 5046 set_reuseaddr(sock); 5047 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5048 debug2_f("bind port %d: %.100s", port, 5049 strerror(errno)); 5050 close(sock); 5051 for (n = 0; n < num_socks; n++) 5052 close(socks[n]); 5053 num_socks = 0; 5054 break; 5055 } 5056 socks[num_socks++] = sock; 5057 if (num_socks == NUM_SOCKS) 5058 break; 5059 } 5060 freeaddrinfo(aitop); 5061 if (num_socks > 0) 5062 break; 5063 } 5064 if (display_number >= MAX_DISPLAYS) { 5065 error("Failed to allocate internet-domain X11 display socket."); 5066 return -1; 5067 } 5068 /* Start listening for connections on the socket. */ 5069 for (n = 0; n < num_socks; n++) { 5070 sock = socks[n]; 5071 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5072 error("listen: %.100s", strerror(errno)); 5073 close(sock); 5074 return -1; 5075 } 5076 } 5077 5078 /* Allocate a channel for each socket. */ 5079 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5080 for (n = 0; n < num_socks; n++) { 5081 sock = socks[n]; 5082 nc = channel_new(ssh, "x11-listener", 5083 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5084 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5085 0, "X11 inet listener", 1); 5086 nc->single_connection = single_connection; 5087 (*chanids)[n] = nc->self; 5088 } 5089 (*chanids)[n] = -1; 5090 5091 /* Return the display number for the DISPLAY environment variable. */ 5092 *display_numberp = display_number; 5093 return 0; 5094 } 5095 5096 static int 5097 connect_local_xsocket_path(const char *pathname) 5098 { 5099 int sock; 5100 struct sockaddr_un addr; 5101 5102 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5103 if (sock == -1) { 5104 error("socket: %.100s", strerror(errno)); 5105 return -1; 5106 } 5107 memset(&addr, 0, sizeof(addr)); 5108 addr.sun_family = AF_UNIX; 5109 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 5110 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5111 return sock; 5112 close(sock); 5113 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5114 return -1; 5115 } 5116 5117 static int 5118 connect_local_xsocket(u_int dnr) 5119 { 5120 char buf[1024]; 5121 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 5122 return connect_local_xsocket_path(buf); 5123 } 5124 5125 #ifdef __APPLE__ 5126 static int 5127 is_path_to_xsocket(const char *display, char *path, size_t pathlen) 5128 { 5129 struct stat sbuf; 5130 5131 if (strlcpy(path, display, pathlen) >= pathlen) { 5132 error("%s: display path too long", __func__); 5133 return 0; 5134 } 5135 if (display[0] != '/') 5136 return 0; 5137 if (stat(path, &sbuf) == 0) { 5138 return 1; 5139 } else { 5140 char *dot = strrchr(path, '.'); 5141 if (dot != NULL) { 5142 *dot = '\0'; 5143 if (stat(path, &sbuf) == 0) { 5144 return 1; 5145 } 5146 } 5147 } 5148 return 0; 5149 } 5150 #endif 5151 5152 int 5153 x11_connect_display(struct ssh *ssh) 5154 { 5155 u_int display_number; 5156 const char *display; 5157 char buf[1024], *cp; 5158 struct addrinfo hints, *ai, *aitop; 5159 char strport[NI_MAXSERV]; 5160 int gaierr, sock = 0; 5161 5162 /* Try to open a socket for the local X server. */ 5163 display = getenv("DISPLAY"); 5164 if (!display) { 5165 error("DISPLAY not set."); 5166 return -1; 5167 } 5168 /* 5169 * Now we decode the value of the DISPLAY variable and make a 5170 * connection to the real X server. 5171 */ 5172 5173 #ifdef __APPLE__ 5174 /* Check if display is a path to a socket (as set by launchd). */ 5175 { 5176 char path[PATH_MAX]; 5177 5178 if (is_path_to_xsocket(display, path, sizeof(path))) { 5179 debug("x11_connect_display: $DISPLAY is launchd"); 5180 5181 /* Create a socket. */ 5182 sock = connect_local_xsocket_path(path); 5183 if (sock < 0) 5184 return -1; 5185 5186 /* OK, we now have a connection to the display. */ 5187 return sock; 5188 } 5189 } 5190 #endif 5191 /* 5192 * Check if it is a unix domain socket. Unix domain displays are in 5193 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5194 */ 5195 if (strncmp(display, "unix:", 5) == 0 || 5196 display[0] == ':') { 5197 /* Connect to the unix domain socket. */ 5198 if (sscanf(strrchr(display, ':') + 1, "%u", 5199 &display_number) != 1) { 5200 error("Could not parse display number from DISPLAY: " 5201 "%.100s", display); 5202 return -1; 5203 } 5204 /* Create a socket. */ 5205 sock = connect_local_xsocket(display_number); 5206 if (sock < 0) 5207 return -1; 5208 5209 /* OK, we now have a connection to the display. */ 5210 return sock; 5211 } 5212 /* 5213 * Connect to an inet socket. The DISPLAY value is supposedly 5214 * hostname:d[.s], where hostname may also be numeric IP address. 5215 */ 5216 strlcpy(buf, display, sizeof(buf)); 5217 cp = strchr(buf, ':'); 5218 if (!cp) { 5219 error("Could not find ':' in DISPLAY: %.100s", display); 5220 return -1; 5221 } 5222 *cp = 0; 5223 /* 5224 * buf now contains the host name. But first we parse the 5225 * display number. 5226 */ 5227 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5228 error("Could not parse display number from DISPLAY: %.100s", 5229 display); 5230 return -1; 5231 } 5232 5233 /* Look up the host address */ 5234 memset(&hints, 0, sizeof(hints)); 5235 hints.ai_family = ssh->chanctxt->IPv4or6; 5236 hints.ai_socktype = SOCK_STREAM; 5237 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5238 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5239 error("%.100s: unknown host. (%s)", buf, 5240 ssh_gai_strerror(gaierr)); 5241 return -1; 5242 } 5243 for (ai = aitop; ai; ai = ai->ai_next) { 5244 /* Create a socket. */ 5245 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5246 if (sock == -1) { 5247 debug2("socket: %.100s", strerror(errno)); 5248 continue; 5249 } 5250 /* Connect it to the display. */ 5251 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5252 debug2("connect %.100s port %u: %.100s", buf, 5253 6000 + display_number, strerror(errno)); 5254 close(sock); 5255 continue; 5256 } 5257 /* Success */ 5258 break; 5259 } 5260 freeaddrinfo(aitop); 5261 if (!ai) { 5262 error("connect %.100s port %u: %.100s", buf, 5263 6000 + display_number, strerror(errno)); 5264 return -1; 5265 } 5266 set_nodelay(sock); 5267 return sock; 5268 } 5269 5270 /* 5271 * Requests forwarding of X11 connections, generates fake authentication 5272 * data, and enables authentication spoofing. 5273 * This should be called in the client only. 5274 */ 5275 void 5276 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5277 const char *disp, const char *proto, const char *data, int want_reply) 5278 { 5279 struct ssh_channels *sc = ssh->chanctxt; 5280 u_int data_len = (u_int) strlen(data) / 2; 5281 u_int i, value; 5282 const char *cp; 5283 char *new_data; 5284 int r, screen_number; 5285 5286 if (sc->x11_saved_display == NULL) 5287 sc->x11_saved_display = xstrdup(disp); 5288 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5289 error("x11_request_forwarding_with_spoofing: different " 5290 "$DISPLAY already forwarded"); 5291 return; 5292 } 5293 5294 cp = strchr(disp, ':'); 5295 if (cp) 5296 cp = strchr(cp, '.'); 5297 if (cp) 5298 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5299 else 5300 screen_number = 0; 5301 5302 if (sc->x11_saved_proto == NULL) { 5303 /* Save protocol name. */ 5304 sc->x11_saved_proto = xstrdup(proto); 5305 5306 /* Extract real authentication data. */ 5307 sc->x11_saved_data = xmalloc(data_len); 5308 for (i = 0; i < data_len; i++) { 5309 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5310 fatal("x11_request_forwarding: bad " 5311 "authentication data: %.100s", data); 5312 } 5313 sc->x11_saved_data[i] = value; 5314 } 5315 sc->x11_saved_data_len = data_len; 5316 5317 /* Generate fake data of the same length. */ 5318 sc->x11_fake_data = xmalloc(data_len); 5319 arc4random_buf(sc->x11_fake_data, data_len); 5320 sc->x11_fake_data_len = data_len; 5321 } 5322 5323 /* Convert the fake data into hex. */ 5324 new_data = tohex(sc->x11_fake_data, data_len); 5325 5326 /* Send the request packet. */ 5327 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5328 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5329 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5330 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5331 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5332 (r = sshpkt_send(ssh)) != 0 || 5333 (r = ssh_packet_write_wait(ssh)) != 0) 5334 fatal_fr(r, "send x11-req"); 5335 free(new_data); 5336 } 5337