1 /* $OpenBSD: channels.c,v 1.436 2024/01/09 22:19:00 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 <sys/types.h> 43 #include <sys/stat.h> 44 #include <sys/ioctl.h> 45 #include <sys/un.h> 46 #include <sys/socket.h> 47 #include <sys/time.h> 48 #include <sys/queue.h> 49 50 #include <netinet/in.h> 51 #include <arpa/inet.h> 52 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <limits.h> 56 #include <netdb.h> 57 #include <poll.h> 58 #include <stdarg.h> 59 #include <stdint.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <termios.h> 64 #include <unistd.h> 65 66 #include "xmalloc.h" 67 #include "ssh.h" 68 #include "ssh2.h" 69 #include "ssherr.h" 70 #include "sshbuf.h" 71 #include "packet.h" 72 #include "log.h" 73 #include "misc.h" 74 #include "channels.h" 75 #include "compat.h" 76 #include "canohost.h" 77 #include "sshkey.h" 78 #include "authfd.h" 79 #include "pathnames.h" 80 #include "match.h" 81 82 /* XXX remove once we're satisfied there's no lurking bugs */ 83 /* #define DEBUG_CHANNEL_POLL 1 */ 84 85 /* -- agent forwarding */ 86 #define NUM_SOCKS 10 87 88 /* -- tcp forwarding */ 89 /* special-case port number meaning allow any port */ 90 #define FWD_PERMIT_ANY_PORT 0 91 92 /* special-case wildcard meaning allow any host */ 93 #define FWD_PERMIT_ANY_HOST "*" 94 95 /* -- X11 forwarding */ 96 /* Maximum number of fake X11 displays to try. */ 97 #define MAX_DISPLAYS 1000 98 99 /* Per-channel callback for pre/post IO actions */ 100 typedef void chan_fn(struct ssh *, Channel *c); 101 102 /* 103 * Data structure for storing which hosts are permitted for forward requests. 104 * The local sides of any remote forwards are stored in this array to prevent 105 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 106 * network (which might be behind a firewall). 107 */ 108 /* XXX: streamlocal wants a path instead of host:port */ 109 /* Overload host_to_connect; we could just make this match Forward */ 110 /* XXX - can we use listen_host instead of listen_path? */ 111 struct permission { 112 char *host_to_connect; /* Connect to 'host'. */ 113 int port_to_connect; /* Connect to 'port'. */ 114 char *listen_host; /* Remote side should listen address. */ 115 char *listen_path; /* Remote side should listen path. */ 116 int listen_port; /* Remote side should listen port. */ 117 Channel *downstream; /* Downstream mux*/ 118 }; 119 120 /* 121 * Stores the forwarding permission state for a single direction (local or 122 * remote). 123 */ 124 struct permission_set { 125 /* 126 * List of all local permitted host/port pairs to allow for the 127 * user. 128 */ 129 u_int num_permitted_user; 130 struct permission *permitted_user; 131 132 /* 133 * List of all permitted host/port pairs to allow for the admin. 134 */ 135 u_int num_permitted_admin; 136 struct permission *permitted_admin; 137 138 /* 139 * If this is true, all opens/listens are permitted. This is the 140 * case on the server on which we have to trust the client anyway, 141 * and the user could do anything after logging in. 142 */ 143 int all_permitted; 144 }; 145 146 /* Used to record timeouts per channel type */ 147 struct ssh_channel_timeout { 148 char *type_pattern; 149 int timeout_secs; 150 }; 151 152 /* Master structure for channels state */ 153 struct ssh_channels { 154 /* 155 * Pointer to an array containing all allocated channels. The array 156 * is dynamically extended as needed. 157 */ 158 Channel **channels; 159 160 /* 161 * Size of the channel array. All slots of the array must always be 162 * initialized (at least the type field); unused slots set to NULL 163 */ 164 u_int channels_alloc; 165 166 /* 167 * 'channel_pre*' are called just before IO to add any bits 168 * relevant to channels in the c->io_want bitmasks. 169 * 170 * 'channel_post*': perform any appropriate operations for 171 * channels which have c->io_ready events pending. 172 */ 173 chan_fn **channel_pre; 174 chan_fn **channel_post; 175 176 /* -- tcp forwarding */ 177 struct permission_set local_perms; 178 struct permission_set remote_perms; 179 180 /* -- X11 forwarding */ 181 182 /* Saved X11 local (client) display. */ 183 char *x11_saved_display; 184 185 /* Saved X11 authentication protocol name. */ 186 char *x11_saved_proto; 187 188 /* Saved X11 authentication data. This is the real data. */ 189 char *x11_saved_data; 190 u_int x11_saved_data_len; 191 192 /* Deadline after which all X11 connections are refused */ 193 time_t x11_refuse_time; 194 195 /* 196 * Fake X11 authentication data. This is what the server will be 197 * sending us; we should replace any occurrences of this by the 198 * real data. 199 */ 200 u_char *x11_fake_data; 201 u_int x11_fake_data_len; 202 203 /* AF_UNSPEC or AF_INET or AF_INET6 */ 204 int IPv4or6; 205 206 /* Channel timeouts by type */ 207 struct ssh_channel_timeout *timeouts; 208 size_t ntimeouts; 209 /* Global timeout for all OPEN channels */ 210 int global_deadline; 211 time_t lastused; 212 }; 213 214 /* helper */ 215 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 216 static const char *channel_rfwd_bind_host(const char *listen_host); 217 218 /* non-blocking connect helpers */ 219 static int connect_next(struct channel_connect *); 220 static void channel_connect_ctx_free(struct channel_connect *); 221 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 222 static int rdynamic_connect_finish(struct ssh *, Channel *); 223 224 /* Setup helper */ 225 static void channel_handler_init(struct ssh_channels *sc); 226 227 /* -- channel core */ 228 229 void 230 channel_init_channels(struct ssh *ssh) 231 { 232 struct ssh_channels *sc; 233 234 if ((sc = calloc(1, sizeof(*sc))) == NULL) 235 fatal_f("allocation failed"); 236 sc->channels_alloc = 10; 237 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 238 sc->IPv4or6 = AF_UNSPEC; 239 channel_handler_init(sc); 240 241 ssh->chanctxt = sc; 242 } 243 244 Channel * 245 channel_by_id(struct ssh *ssh, int id) 246 { 247 Channel *c; 248 249 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 250 logit_f("%d: bad id", id); 251 return NULL; 252 } 253 c = ssh->chanctxt->channels[id]; 254 if (c == NULL) { 255 logit_f("%d: bad id: channel free", id); 256 return NULL; 257 } 258 return c; 259 } 260 261 Channel * 262 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 263 { 264 Channel *c; 265 u_int i; 266 267 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 268 c = ssh->chanctxt->channels[i]; 269 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 270 return c; 271 } 272 return NULL; 273 } 274 275 /* 276 * Returns the channel if it is allowed to receive protocol messages. 277 * Private channels, like listening sockets, may not receive messages. 278 */ 279 Channel * 280 channel_lookup(struct ssh *ssh, int id) 281 { 282 Channel *c; 283 284 if ((c = channel_by_id(ssh, id)) == NULL) 285 return NULL; 286 287 switch (c->type) { 288 case SSH_CHANNEL_X11_OPEN: 289 case SSH_CHANNEL_LARVAL: 290 case SSH_CHANNEL_CONNECTING: 291 case SSH_CHANNEL_DYNAMIC: 292 case SSH_CHANNEL_RDYNAMIC_OPEN: 293 case SSH_CHANNEL_RDYNAMIC_FINISH: 294 case SSH_CHANNEL_OPENING: 295 case SSH_CHANNEL_OPEN: 296 case SSH_CHANNEL_ABANDONED: 297 case SSH_CHANNEL_MUX_PROXY: 298 return c; 299 } 300 logit("Non-public channel %d, type %d.", id, c->type); 301 return NULL; 302 } 303 304 /* 305 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 306 * match type_pattern. 307 */ 308 void 309 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 310 int timeout_secs) 311 { 312 struct ssh_channels *sc = ssh->chanctxt; 313 314 if (strcmp(type_pattern, "global") == 0) { 315 debug2_f("global channel timeout %d seconds", timeout_secs); 316 sc->global_deadline = timeout_secs; 317 return; 318 } 319 debug2_f("channel type \"%s\" timeout %d seconds", 320 type_pattern, timeout_secs); 321 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 322 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 323 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 324 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 325 sc->ntimeouts++; 326 } 327 328 /* Clears all previously-added channel timeouts */ 329 void 330 channel_clear_timeouts(struct ssh *ssh) 331 { 332 struct ssh_channels *sc = ssh->chanctxt; 333 size_t i; 334 335 debug3_f("clearing"); 336 for (i = 0; i < sc->ntimeouts; i++) 337 free(sc->timeouts[i].type_pattern); 338 free(sc->timeouts); 339 sc->timeouts = NULL; 340 sc->ntimeouts = 0; 341 } 342 343 static int 344 lookup_timeout(struct ssh *ssh, const char *type) 345 { 346 struct ssh_channels *sc = ssh->chanctxt; 347 size_t i; 348 349 for (i = 0; i < sc->ntimeouts; i++) { 350 if (match_pattern(type, sc->timeouts[i].type_pattern)) 351 return sc->timeouts[i].timeout_secs; 352 } 353 354 return 0; 355 } 356 357 /* 358 * Sets "extended type" of a channel; used by session layer to add additional 359 * information about channel types (e.g. shell, login, subsystem) that can then 360 * be used to select timeouts. 361 * Will reset c->inactive_deadline as a side-effect. 362 */ 363 void 364 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 365 { 366 Channel *c; 367 368 if ((c = channel_by_id(ssh, id)) == NULL) 369 fatal_f("missing channel %d", id); 370 if (c->xctype != NULL) 371 free(c->xctype); 372 c->xctype = xstrdup(xctype); 373 /* Type has changed, so look up inactivity deadline again */ 374 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 375 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 376 c->inactive_deadline); 377 } 378 379 /* 380 * update "last used" time on a channel. 381 * NB. nothing else should update lastused except to clear it. 382 */ 383 static void 384 channel_set_used_time(struct ssh *ssh, Channel *c) 385 { 386 ssh->chanctxt->lastused = monotime(); 387 if (c != NULL) 388 c->lastused = ssh->chanctxt->lastused; 389 } 390 391 /* 392 * Get the time at which a channel is due to time out for inactivity. 393 * Returns 0 if the channel is not due to time out ever. 394 */ 395 static time_t 396 channel_get_expiry(struct ssh *ssh, Channel *c) 397 { 398 struct ssh_channels *sc = ssh->chanctxt; 399 time_t expiry = 0, channel_expiry; 400 401 if (sc->lastused != 0 && sc->global_deadline != 0) 402 expiry = sc->lastused + sc->global_deadline; 403 if (c->lastused != 0 && c->inactive_deadline != 0) { 404 channel_expiry = c->lastused + c->inactive_deadline; 405 if (expiry == 0 || channel_expiry < expiry) 406 expiry = channel_expiry; 407 } 408 return expiry; 409 } 410 411 /* 412 * Register filedescriptors for a channel, used when allocating a channel or 413 * when the channel consumer/producer is ready, e.g. shell exec'd 414 */ 415 static void 416 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 417 int extusage, int nonblock, int is_tty) 418 { 419 int val; 420 421 if (rfd != -1) 422 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 423 if (wfd != -1 && wfd != rfd) 424 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 425 if (efd != -1 && efd != rfd && efd != wfd) 426 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 427 428 c->rfd = rfd; 429 c->wfd = wfd; 430 c->sock = (rfd == wfd) ? rfd : -1; 431 c->efd = efd; 432 c->extended_usage = extusage; 433 434 if ((c->isatty = is_tty) != 0) 435 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 436 437 /* enable nonblocking mode */ 438 c->restore_block = 0; 439 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 440 /* 441 * Special handling for stdio file descriptors: do not set 442 * non-blocking mode if they are TTYs. Otherwise prepare to 443 * restore their blocking state on exit to avoid interfering 444 * with other programs that follow. 445 */ 446 if (rfd != -1 && !isatty(rfd) && 447 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 448 c->restore_flags[0] = val; 449 c->restore_block |= CHANNEL_RESTORE_RFD; 450 set_nonblock(rfd); 451 } 452 if (wfd != -1 && !isatty(wfd) && 453 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 454 c->restore_flags[1] = val; 455 c->restore_block |= CHANNEL_RESTORE_WFD; 456 set_nonblock(wfd); 457 } 458 if (efd != -1 && !isatty(efd) && 459 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 460 c->restore_flags[2] = val; 461 c->restore_block |= CHANNEL_RESTORE_EFD; 462 set_nonblock(efd); 463 } 464 } else if (nonblock) { 465 if (rfd != -1) 466 set_nonblock(rfd); 467 if (wfd != -1) 468 set_nonblock(wfd); 469 if (efd != -1) 470 set_nonblock(efd); 471 } 472 /* channel might be entering a larval state, so reset global timeout */ 473 channel_set_used_time(ssh, NULL); 474 } 475 476 /* 477 * Allocate a new channel object and set its type and socket. 478 */ 479 Channel * 480 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 481 u_int window, u_int maxpack, int extusage, const char *remote_name, 482 int nonblock) 483 { 484 struct ssh_channels *sc = ssh->chanctxt; 485 u_int i, found; 486 Channel *c; 487 int r; 488 489 /* Try to find a free slot where to put the new channel. */ 490 for (i = 0; i < sc->channels_alloc; i++) { 491 if (sc->channels[i] == NULL) { 492 /* Found a free slot. */ 493 found = i; 494 break; 495 } 496 } 497 if (i >= sc->channels_alloc) { 498 /* 499 * There are no free slots. Take last+1 slot and expand 500 * the array. 501 */ 502 found = sc->channels_alloc; 503 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 504 fatal_f("internal error: channels_alloc %d too big", 505 sc->channels_alloc); 506 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 507 sc->channels_alloc + 10, sizeof(*sc->channels)); 508 sc->channels_alloc += 10; 509 debug2("channel: expanding %d", sc->channels_alloc); 510 } 511 /* Initialize and return new channel. */ 512 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 513 if ((c->input = sshbuf_new()) == NULL || 514 (c->output = sshbuf_new()) == NULL || 515 (c->extended = sshbuf_new()) == NULL) 516 fatal_f("sshbuf_new failed"); 517 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 518 fatal_fr(r, "sshbuf_set_max_size"); 519 c->ostate = CHAN_OUTPUT_OPEN; 520 c->istate = CHAN_INPUT_OPEN; 521 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 522 c->self = found; 523 c->type = type; 524 c->ctype = ctype; 525 c->local_window = window; 526 c->local_window_max = window; 527 c->local_maxpacket = maxpack; 528 c->remote_name = xstrdup(remote_name); 529 c->ctl_chan = -1; 530 c->delayed = 1; /* prevent call to channel_post handler */ 531 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 532 TAILQ_INIT(&c->status_confirms); 533 debug("channel %d: new %s [%s] (inactive timeout: %u)", 534 found, c->ctype, remote_name, c->inactive_deadline); 535 return c; 536 } 537 538 int 539 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 540 { 541 int ret, fd = *fdp; 542 543 if (fd == -1) 544 return 0; 545 546 /* restore blocking */ 547 if (*fdp == c->rfd && 548 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 549 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 550 else if (*fdp == c->wfd && 551 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 552 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 553 else if (*fdp == c->efd && 554 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 555 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 556 557 if (*fdp == c->rfd) { 558 c->io_want &= ~SSH_CHAN_IO_RFD; 559 c->io_ready &= ~SSH_CHAN_IO_RFD; 560 c->rfd = -1; 561 c->pfds[0] = -1; 562 } 563 if (*fdp == c->wfd) { 564 c->io_want &= ~SSH_CHAN_IO_WFD; 565 c->io_ready &= ~SSH_CHAN_IO_WFD; 566 c->wfd = -1; 567 c->pfds[1] = -1; 568 } 569 if (*fdp == c->efd) { 570 c->io_want &= ~SSH_CHAN_IO_EFD; 571 c->io_ready &= ~SSH_CHAN_IO_EFD; 572 c->efd = -1; 573 c->pfds[2] = -1; 574 } 575 if (*fdp == c->sock) { 576 c->io_want &= ~SSH_CHAN_IO_SOCK; 577 c->io_ready &= ~SSH_CHAN_IO_SOCK; 578 c->sock = -1; 579 c->pfds[3] = -1; 580 } 581 582 ret = close(fd); 583 *fdp = -1; /* probably redundant */ 584 return ret; 585 } 586 587 /* Close all channel fd/socket. */ 588 static void 589 channel_close_fds(struct ssh *ssh, Channel *c) 590 { 591 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 592 593 channel_close_fd(ssh, c, &c->sock); 594 if (rfd != sock) 595 channel_close_fd(ssh, c, &c->rfd); 596 if (wfd != sock && wfd != rfd) 597 channel_close_fd(ssh, c, &c->wfd); 598 if (efd != sock && efd != rfd && efd != wfd) 599 channel_close_fd(ssh, c, &c->efd); 600 } 601 602 static void 603 fwd_perm_clear(struct permission *perm) 604 { 605 free(perm->host_to_connect); 606 free(perm->listen_host); 607 free(perm->listen_path); 608 memset(perm, 0, sizeof(*perm)); 609 } 610 611 /* Returns an printable name for the specified forwarding permission list */ 612 static const char * 613 fwd_ident(int who, int where) 614 { 615 if (who == FORWARD_ADM) { 616 if (where == FORWARD_LOCAL) 617 return "admin local"; 618 else if (where == FORWARD_REMOTE) 619 return "admin remote"; 620 } else if (who == FORWARD_USER) { 621 if (where == FORWARD_LOCAL) 622 return "user local"; 623 else if (where == FORWARD_REMOTE) 624 return "user remote"; 625 } 626 fatal("Unknown forward permission list %d/%d", who, where); 627 } 628 629 /* Returns the forwarding permission list for the specified direction */ 630 static struct permission_set * 631 permission_set_get(struct ssh *ssh, int where) 632 { 633 struct ssh_channels *sc = ssh->chanctxt; 634 635 switch (where) { 636 case FORWARD_LOCAL: 637 return &sc->local_perms; 638 break; 639 case FORWARD_REMOTE: 640 return &sc->remote_perms; 641 break; 642 default: 643 fatal_f("invalid forwarding direction %d", where); 644 } 645 } 646 647 /* Returns pointers to the specified forwarding list and its element count */ 648 static void 649 permission_set_get_array(struct ssh *ssh, int who, int where, 650 struct permission ***permpp, u_int **npermpp) 651 { 652 struct permission_set *pset = permission_set_get(ssh, where); 653 654 switch (who) { 655 case FORWARD_USER: 656 *permpp = &pset->permitted_user; 657 *npermpp = &pset->num_permitted_user; 658 break; 659 case FORWARD_ADM: 660 *permpp = &pset->permitted_admin; 661 *npermpp = &pset->num_permitted_admin; 662 break; 663 default: 664 fatal_f("invalid forwarding client %d", who); 665 } 666 } 667 668 /* Adds an entry to the specified forwarding list */ 669 static int 670 permission_set_add(struct ssh *ssh, int who, int where, 671 const char *host_to_connect, int port_to_connect, 672 const char *listen_host, const char *listen_path, int listen_port, 673 Channel *downstream) 674 { 675 struct permission **permp; 676 u_int n, *npermp; 677 678 permission_set_get_array(ssh, who, where, &permp, &npermp); 679 680 if (*npermp >= INT_MAX) 681 fatal_f("%s overflow", fwd_ident(who, where)); 682 683 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 684 n = (*npermp)++; 685 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 686 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 687 (*permp)[n].port_to_connect = port_to_connect; 688 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 689 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 690 (*permp)[n].listen_port = listen_port; 691 (*permp)[n].downstream = downstream; 692 #undef MAYBE_DUP 693 return (int)n; 694 } 695 696 static void 697 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 698 { 699 struct ssh_channels *sc = ssh->chanctxt; 700 struct permission_set *pset = &sc->local_perms; 701 struct permission *perm; 702 int r; 703 u_int i; 704 705 for (i = 0; i < pset->num_permitted_user; i++) { 706 perm = &pset->permitted_user[i]; 707 if (perm->downstream != c) 708 continue; 709 710 /* cancel on the server, since mux client is gone */ 711 debug("channel %d: cleanup remote forward for %s:%u", 712 c->self, perm->listen_host, perm->listen_port); 713 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 714 (r = sshpkt_put_cstring(ssh, 715 "cancel-tcpip-forward")) != 0 || 716 (r = sshpkt_put_u8(ssh, 0)) != 0 || 717 (r = sshpkt_put_cstring(ssh, 718 channel_rfwd_bind_host(perm->listen_host))) != 0 || 719 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 720 (r = sshpkt_send(ssh)) != 0) { 721 fatal_fr(r, "channel %i", c->self); 722 } 723 fwd_perm_clear(perm); /* unregister */ 724 } 725 } 726 727 /* Free the channel and close its fd/socket. */ 728 void 729 channel_free(struct ssh *ssh, Channel *c) 730 { 731 struct ssh_channels *sc = ssh->chanctxt; 732 char *s; 733 u_int i, n; 734 Channel *other; 735 struct channel_confirm *cc; 736 737 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 738 if ((other = sc->channels[i]) == NULL) 739 continue; 740 n++; 741 /* detach from mux client and prepare for closing */ 742 if (c->type == SSH_CHANNEL_MUX_CLIENT && 743 other->type == SSH_CHANNEL_MUX_PROXY && 744 other->mux_ctx == c) { 745 other->mux_ctx = NULL; 746 other->type = SSH_CHANNEL_OPEN; 747 other->istate = CHAN_INPUT_CLOSED; 748 other->ostate = CHAN_OUTPUT_CLOSED; 749 } 750 } 751 debug("channel %d: free: %s, nchannels %u", c->self, 752 c->remote_name ? c->remote_name : "???", n); 753 754 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 755 mux_remove_remote_forwardings(ssh, c); 756 free(c->mux_ctx); 757 c->mux_ctx = NULL; 758 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 759 free(c->mux_ctx); 760 c->mux_ctx = NULL; 761 } 762 763 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 764 s = channel_open_message(ssh); 765 debug3("channel %d: status: %s", c->self, s); 766 free(s); 767 } 768 769 channel_close_fds(ssh, c); 770 sshbuf_free(c->input); 771 sshbuf_free(c->output); 772 sshbuf_free(c->extended); 773 c->input = c->output = c->extended = NULL; 774 free(c->remote_name); 775 c->remote_name = NULL; 776 free(c->path); 777 c->path = NULL; 778 free(c->listening_addr); 779 c->listening_addr = NULL; 780 free(c->xctype); 781 c->xctype = NULL; 782 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 783 if (cc->abandon_cb != NULL) 784 cc->abandon_cb(ssh, c, cc->ctx); 785 TAILQ_REMOVE(&c->status_confirms, cc, entry); 786 freezero(cc, sizeof(*cc)); 787 } 788 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 789 c->filter_cleanup(ssh, c->self, c->filter_ctx); 790 sc->channels[c->self] = NULL; 791 freezero(c, sizeof(*c)); 792 } 793 794 void 795 channel_free_all(struct ssh *ssh) 796 { 797 u_int i; 798 struct ssh_channels *sc = ssh->chanctxt; 799 800 for (i = 0; i < sc->channels_alloc; i++) 801 if (sc->channels[i] != NULL) 802 channel_free(ssh, sc->channels[i]); 803 804 free(sc->channels); 805 sc->channels = NULL; 806 sc->channels_alloc = 0; 807 808 free(sc->x11_saved_display); 809 sc->x11_saved_display = NULL; 810 811 free(sc->x11_saved_proto); 812 sc->x11_saved_proto = NULL; 813 814 free(sc->x11_saved_data); 815 sc->x11_saved_data = NULL; 816 sc->x11_saved_data_len = 0; 817 818 free(sc->x11_fake_data); 819 sc->x11_fake_data = NULL; 820 sc->x11_fake_data_len = 0; 821 } 822 823 /* 824 * Closes the sockets/fds of all channels. This is used to close extra file 825 * descriptors after a fork. 826 */ 827 void 828 channel_close_all(struct ssh *ssh) 829 { 830 u_int i; 831 832 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 833 if (ssh->chanctxt->channels[i] != NULL) 834 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 835 } 836 837 /* 838 * Stop listening to channels. 839 */ 840 void 841 channel_stop_listening(struct ssh *ssh) 842 { 843 u_int i; 844 Channel *c; 845 846 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 847 c = ssh->chanctxt->channels[i]; 848 if (c != NULL) { 849 switch (c->type) { 850 case SSH_CHANNEL_AUTH_SOCKET: 851 case SSH_CHANNEL_PORT_LISTENER: 852 case SSH_CHANNEL_RPORT_LISTENER: 853 case SSH_CHANNEL_X11_LISTENER: 854 case SSH_CHANNEL_UNIX_LISTENER: 855 case SSH_CHANNEL_RUNIX_LISTENER: 856 channel_close_fd(ssh, c, &c->sock); 857 channel_free(ssh, c); 858 break; 859 } 860 } 861 } 862 } 863 864 /* 865 * Returns true if no channel has too much buffered data, and false if one or 866 * more channel is overfull. 867 */ 868 int 869 channel_not_very_much_buffered_data(struct ssh *ssh) 870 { 871 u_int i; 872 u_int maxsize = ssh_packet_get_maxsize(ssh); 873 Channel *c; 874 875 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 876 c = ssh->chanctxt->channels[i]; 877 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 878 continue; 879 if (sshbuf_len(c->output) > maxsize) { 880 debug2("channel %d: big output buffer %zu > %u", 881 c->self, sshbuf_len(c->output), maxsize); 882 return 0; 883 } 884 } 885 return 1; 886 } 887 888 /* Returns true if any channel is still open. */ 889 int 890 channel_still_open(struct ssh *ssh) 891 { 892 u_int i; 893 Channel *c; 894 895 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 896 c = ssh->chanctxt->channels[i]; 897 if (c == NULL) 898 continue; 899 switch (c->type) { 900 case SSH_CHANNEL_X11_LISTENER: 901 case SSH_CHANNEL_PORT_LISTENER: 902 case SSH_CHANNEL_RPORT_LISTENER: 903 case SSH_CHANNEL_MUX_LISTENER: 904 case SSH_CHANNEL_CLOSED: 905 case SSH_CHANNEL_AUTH_SOCKET: 906 case SSH_CHANNEL_DYNAMIC: 907 case SSH_CHANNEL_RDYNAMIC_OPEN: 908 case SSH_CHANNEL_CONNECTING: 909 case SSH_CHANNEL_ZOMBIE: 910 case SSH_CHANNEL_ABANDONED: 911 case SSH_CHANNEL_UNIX_LISTENER: 912 case SSH_CHANNEL_RUNIX_LISTENER: 913 continue; 914 case SSH_CHANNEL_LARVAL: 915 continue; 916 case SSH_CHANNEL_OPENING: 917 case SSH_CHANNEL_OPEN: 918 case SSH_CHANNEL_RDYNAMIC_FINISH: 919 case SSH_CHANNEL_X11_OPEN: 920 case SSH_CHANNEL_MUX_CLIENT: 921 case SSH_CHANNEL_MUX_PROXY: 922 return 1; 923 default: 924 fatal_f("bad channel type %d", c->type); 925 /* NOTREACHED */ 926 } 927 } 928 return 0; 929 } 930 931 /* Returns true if a channel with a TTY is open. */ 932 int 933 channel_tty_open(struct ssh *ssh) 934 { 935 u_int i; 936 Channel *c; 937 938 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 939 c = ssh->chanctxt->channels[i]; 940 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 941 continue; 942 if (c->client_tty) 943 return 1; 944 } 945 return 0; 946 } 947 948 /* Returns the id of an open channel suitable for keepaliving */ 949 int 950 channel_find_open(struct ssh *ssh) 951 { 952 u_int i; 953 Channel *c; 954 955 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 956 c = ssh->chanctxt->channels[i]; 957 if (c == NULL || !c->have_remote_id) 958 continue; 959 switch (c->type) { 960 case SSH_CHANNEL_CLOSED: 961 case SSH_CHANNEL_DYNAMIC: 962 case SSH_CHANNEL_RDYNAMIC_OPEN: 963 case SSH_CHANNEL_RDYNAMIC_FINISH: 964 case SSH_CHANNEL_X11_LISTENER: 965 case SSH_CHANNEL_PORT_LISTENER: 966 case SSH_CHANNEL_RPORT_LISTENER: 967 case SSH_CHANNEL_MUX_LISTENER: 968 case SSH_CHANNEL_MUX_CLIENT: 969 case SSH_CHANNEL_MUX_PROXY: 970 case SSH_CHANNEL_OPENING: 971 case SSH_CHANNEL_CONNECTING: 972 case SSH_CHANNEL_ZOMBIE: 973 case SSH_CHANNEL_ABANDONED: 974 case SSH_CHANNEL_UNIX_LISTENER: 975 case SSH_CHANNEL_RUNIX_LISTENER: 976 continue; 977 case SSH_CHANNEL_LARVAL: 978 case SSH_CHANNEL_AUTH_SOCKET: 979 case SSH_CHANNEL_OPEN: 980 case SSH_CHANNEL_X11_OPEN: 981 return i; 982 default: 983 fatal_f("bad channel type %d", c->type); 984 /* NOTREACHED */ 985 } 986 } 987 return -1; 988 } 989 990 /* Returns the state of the channel's extended usage flag */ 991 const char * 992 channel_format_extended_usage(const Channel *c) 993 { 994 if (c->efd == -1) 995 return "closed"; 996 997 switch (c->extended_usage) { 998 case CHAN_EXTENDED_WRITE: 999 return "write"; 1000 case CHAN_EXTENDED_READ: 1001 return "read"; 1002 case CHAN_EXTENDED_IGNORE: 1003 return "ignore"; 1004 default: 1005 return "UNKNOWN"; 1006 } 1007 } 1008 1009 static char * 1010 channel_format_status(const Channel *c) 1011 { 1012 char *ret = NULL; 1013 1014 xasprintf(&ret, "t%d [%s] %s%u i%u/%zu o%u/%zu e[%s]/%zu " 1015 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 1016 c->type, c->xctype != NULL ? c->xctype : c->ctype, 1017 c->have_remote_id ? "r" : "nr", c->remote_id, 1018 c->istate, sshbuf_len(c->input), 1019 c->ostate, sshbuf_len(c->output), 1020 channel_format_extended_usage(c), sshbuf_len(c->extended), 1021 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 1022 c->io_want, c->io_ready); 1023 return ret; 1024 } 1025 1026 /* 1027 * Returns a message describing the currently open forwarded connections, 1028 * suitable for sending to the client. The message contains crlf pairs for 1029 * newlines. 1030 */ 1031 char * 1032 channel_open_message(struct ssh *ssh) 1033 { 1034 struct sshbuf *buf; 1035 Channel *c; 1036 u_int i; 1037 int r; 1038 char *cp, *ret; 1039 1040 if ((buf = sshbuf_new()) == NULL) 1041 fatal_f("sshbuf_new"); 1042 if ((r = sshbuf_putf(buf, 1043 "The following connections are open:\r\n")) != 0) 1044 fatal_fr(r, "sshbuf_putf"); 1045 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1046 c = ssh->chanctxt->channels[i]; 1047 if (c == NULL) 1048 continue; 1049 switch (c->type) { 1050 case SSH_CHANNEL_X11_LISTENER: 1051 case SSH_CHANNEL_PORT_LISTENER: 1052 case SSH_CHANNEL_RPORT_LISTENER: 1053 case SSH_CHANNEL_CLOSED: 1054 case SSH_CHANNEL_AUTH_SOCKET: 1055 case SSH_CHANNEL_ZOMBIE: 1056 case SSH_CHANNEL_ABANDONED: 1057 case SSH_CHANNEL_MUX_LISTENER: 1058 case SSH_CHANNEL_UNIX_LISTENER: 1059 case SSH_CHANNEL_RUNIX_LISTENER: 1060 continue; 1061 case SSH_CHANNEL_LARVAL: 1062 case SSH_CHANNEL_OPENING: 1063 case SSH_CHANNEL_CONNECTING: 1064 case SSH_CHANNEL_DYNAMIC: 1065 case SSH_CHANNEL_RDYNAMIC_OPEN: 1066 case SSH_CHANNEL_RDYNAMIC_FINISH: 1067 case SSH_CHANNEL_OPEN: 1068 case SSH_CHANNEL_X11_OPEN: 1069 case SSH_CHANNEL_MUX_PROXY: 1070 case SSH_CHANNEL_MUX_CLIENT: 1071 cp = channel_format_status(c); 1072 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1073 c->self, c->remote_name, cp)) != 0) { 1074 free(cp); 1075 fatal_fr(r, "sshbuf_putf"); 1076 } 1077 free(cp); 1078 continue; 1079 default: 1080 fatal_f("bad channel type %d", c->type); 1081 /* NOTREACHED */ 1082 } 1083 } 1084 if ((ret = sshbuf_dup_string(buf)) == NULL) 1085 fatal_f("sshbuf_dup_string"); 1086 sshbuf_free(buf); 1087 return ret; 1088 } 1089 1090 static void 1091 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1092 { 1093 int r; 1094 1095 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1096 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1097 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1098 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1099 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1100 fatal_r(r, "%s: channel %i: open", where, c->self); 1101 } 1102 } 1103 1104 void 1105 channel_send_open(struct ssh *ssh, int id) 1106 { 1107 Channel *c = channel_lookup(ssh, id); 1108 int r; 1109 1110 if (c == NULL) { 1111 logit("channel_send_open: %d: bad id", id); 1112 return; 1113 } 1114 debug2("channel %d: send open", id); 1115 open_preamble(ssh, __func__, c, c->ctype); 1116 if ((r = sshpkt_send(ssh)) != 0) 1117 fatal_fr(r, "channel %i", c->self); 1118 } 1119 1120 void 1121 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 1122 { 1123 Channel *c = channel_lookup(ssh, id); 1124 int r; 1125 1126 if (c == NULL) { 1127 logit_f("%d: unknown channel id", id); 1128 return; 1129 } 1130 if (!c->have_remote_id) 1131 fatal_f("channel %d: no remote id", c->self); 1132 1133 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1134 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1135 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1136 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1137 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1138 fatal_fr(r, "channel %i", c->self); 1139 } 1140 } 1141 1142 void 1143 channel_register_status_confirm(struct ssh *ssh, int id, 1144 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1145 { 1146 struct channel_confirm *cc; 1147 Channel *c; 1148 1149 if ((c = channel_lookup(ssh, id)) == NULL) 1150 fatal_f("%d: bad id", id); 1151 1152 cc = xcalloc(1, sizeof(*cc)); 1153 cc->cb = cb; 1154 cc->abandon_cb = abandon_cb; 1155 cc->ctx = ctx; 1156 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1157 } 1158 1159 void 1160 channel_register_open_confirm(struct ssh *ssh, int id, 1161 channel_open_fn *fn, void *ctx) 1162 { 1163 Channel *c = channel_lookup(ssh, id); 1164 1165 if (c == NULL) { 1166 logit_f("%d: bad id", id); 1167 return; 1168 } 1169 c->open_confirm = fn; 1170 c->open_confirm_ctx = ctx; 1171 } 1172 1173 void 1174 channel_register_cleanup(struct ssh *ssh, int id, 1175 channel_callback_fn *fn, int do_close) 1176 { 1177 Channel *c = channel_by_id(ssh, id); 1178 1179 if (c == NULL) { 1180 logit_f("%d: bad id", id); 1181 return; 1182 } 1183 c->detach_user = fn; 1184 c->detach_close = do_close; 1185 } 1186 1187 void 1188 channel_cancel_cleanup(struct ssh *ssh, int id) 1189 { 1190 Channel *c = channel_by_id(ssh, id); 1191 1192 if (c == NULL) { 1193 logit_f("%d: bad id", id); 1194 return; 1195 } 1196 c->detach_user = NULL; 1197 c->detach_close = 0; 1198 } 1199 1200 void 1201 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1202 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1203 { 1204 Channel *c = channel_lookup(ssh, id); 1205 1206 if (c == NULL) { 1207 logit_f("%d: bad id", id); 1208 return; 1209 } 1210 c->input_filter = ifn; 1211 c->output_filter = ofn; 1212 c->filter_ctx = ctx; 1213 c->filter_cleanup = cfn; 1214 } 1215 1216 void 1217 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1218 int extusage, int nonblock, int is_tty, u_int window_max) 1219 { 1220 Channel *c = channel_lookup(ssh, id); 1221 int r; 1222 1223 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1224 fatal("channel_activate for non-larval channel %d.", id); 1225 if (!c->have_remote_id) 1226 fatal_f("channel %d: no remote id", c->self); 1227 1228 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1229 c->type = SSH_CHANNEL_OPEN; 1230 channel_set_used_time(ssh, c); 1231 c->local_window = c->local_window_max = window_max; 1232 1233 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1234 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1235 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1236 (r = sshpkt_send(ssh)) != 0) 1237 fatal_fr(r, "channel %i", c->self); 1238 } 1239 1240 static void 1241 channel_pre_listener(struct ssh *ssh, Channel *c) 1242 { 1243 c->io_want = SSH_CHAN_IO_SOCK_R; 1244 } 1245 1246 static void 1247 channel_pre_connecting(struct ssh *ssh, Channel *c) 1248 { 1249 debug3("channel %d: waiting for connection", c->self); 1250 c->io_want = SSH_CHAN_IO_SOCK_W; 1251 } 1252 1253 static void 1254 channel_pre_open(struct ssh *ssh, Channel *c) 1255 { 1256 c->io_want = 0; 1257 if (c->istate == CHAN_INPUT_OPEN && 1258 c->remote_window > 0 && 1259 sshbuf_len(c->input) < c->remote_window && 1260 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1261 c->io_want |= SSH_CHAN_IO_RFD; 1262 if (c->ostate == CHAN_OUTPUT_OPEN || 1263 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1264 if (sshbuf_len(c->output) > 0) { 1265 c->io_want |= SSH_CHAN_IO_WFD; 1266 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1267 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1268 debug2("channel %d: " 1269 "obuf_empty delayed efd %d/(%zu)", c->self, 1270 c->efd, sshbuf_len(c->extended)); 1271 else 1272 chan_obuf_empty(ssh, c); 1273 } 1274 } 1275 /** XXX check close conditions, too */ 1276 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1277 c->ostate == CHAN_OUTPUT_CLOSED)) { 1278 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1279 sshbuf_len(c->extended) > 0) 1280 c->io_want |= SSH_CHAN_IO_EFD_W; 1281 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1282 (c->extended_usage == CHAN_EXTENDED_READ || 1283 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1284 sshbuf_len(c->extended) < c->remote_window) 1285 c->io_want |= SSH_CHAN_IO_EFD_R; 1286 } 1287 /* XXX: What about efd? races? */ 1288 } 1289 1290 /* 1291 * This is a special state for X11 authentication spoofing. An opened X11 1292 * connection (when authentication spoofing is being done) remains in this 1293 * state until the first packet has been completely read. The authentication 1294 * data in that packet is then substituted by the real data if it matches the 1295 * fake data, and the channel is put into normal mode. 1296 * XXX All this happens at the client side. 1297 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1298 */ 1299 static int 1300 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1301 { 1302 struct ssh_channels *sc = ssh->chanctxt; 1303 u_char *ucp; 1304 u_int proto_len, data_len; 1305 1306 /* Is this being called after the refusal deadline? */ 1307 if (sc->x11_refuse_time != 0 && 1308 monotime() >= sc->x11_refuse_time) { 1309 verbose("Rejected X11 connection after ForwardX11Timeout " 1310 "expired"); 1311 return -1; 1312 } 1313 1314 /* Check if the fixed size part of the packet is in buffer. */ 1315 if (sshbuf_len(b) < 12) 1316 return 0; 1317 1318 /* Parse the lengths of variable-length fields. */ 1319 ucp = sshbuf_mutable_ptr(b); 1320 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1321 proto_len = 256 * ucp[6] + ucp[7]; 1322 data_len = 256 * ucp[8] + ucp[9]; 1323 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1324 proto_len = ucp[6] + 256 * ucp[7]; 1325 data_len = ucp[8] + 256 * ucp[9]; 1326 } else { 1327 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1328 ucp[0]); 1329 return -1; 1330 } 1331 1332 /* Check if the whole packet is in buffer. */ 1333 if (sshbuf_len(b) < 1334 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1335 return 0; 1336 1337 /* Check if authentication protocol matches. */ 1338 if (proto_len != strlen(sc->x11_saved_proto) || 1339 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1340 debug2("X11 connection uses different authentication protocol."); 1341 return -1; 1342 } 1343 /* Check if authentication data matches our fake data. */ 1344 if (data_len != sc->x11_fake_data_len || 1345 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1346 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1347 debug2("X11 auth data does not match fake data."); 1348 return -1; 1349 } 1350 /* Check fake data length */ 1351 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1352 error("X11 fake_data_len %d != saved_data_len %d", 1353 sc->x11_fake_data_len, sc->x11_saved_data_len); 1354 return -1; 1355 } 1356 /* 1357 * Received authentication protocol and data match 1358 * our fake data. Substitute the fake data with real 1359 * data. 1360 */ 1361 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1362 sc->x11_saved_data, sc->x11_saved_data_len); 1363 return 1; 1364 } 1365 1366 void 1367 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1368 { 1369 debug3_f("channel %d: forcibly closing", c->self); 1370 if (c->istate == CHAN_INPUT_OPEN) 1371 chan_read_failed(ssh, c); 1372 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1373 sshbuf_reset(c->input); 1374 chan_ibuf_empty(ssh, c); 1375 } 1376 if (c->ostate == CHAN_OUTPUT_OPEN || 1377 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1378 sshbuf_reset(c->output); 1379 chan_write_failed(ssh, c); 1380 } 1381 if (c->detach_user) 1382 c->detach_user(ssh, c->self, 1, NULL); 1383 if (c->efd != -1) 1384 channel_close_fd(ssh, c, &c->efd); 1385 if (abandon) 1386 c->type = SSH_CHANNEL_ABANDONED; 1387 /* exempt from inactivity timeouts */ 1388 c->inactive_deadline = 0; 1389 c->lastused = 0; 1390 } 1391 1392 static void 1393 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1394 { 1395 int ret = x11_open_helper(ssh, c->output); 1396 1397 /* c->force_drain = 1; */ 1398 1399 if (ret == 1) { 1400 c->type = SSH_CHANNEL_OPEN; 1401 channel_set_used_time(ssh, c); 1402 channel_pre_open(ssh, c); 1403 } else if (ret == -1) { 1404 logit("X11 connection rejected because of wrong " 1405 "authentication."); 1406 debug2("X11 rejected %d i%d/o%d", 1407 c->self, c->istate, c->ostate); 1408 channel_force_close(ssh, c, 0); 1409 } 1410 } 1411 1412 static void 1413 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1414 { 1415 c->io_want = 0; 1416 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1417 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1418 c->io_want |= SSH_CHAN_IO_RFD; 1419 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1420 /* clear buffer immediately (discard any partial packet) */ 1421 sshbuf_reset(c->input); 1422 chan_ibuf_empty(ssh, c); 1423 /* Start output drain. XXX just kill chan? */ 1424 chan_rcvd_oclose(ssh, c); 1425 } 1426 if (c->ostate == CHAN_OUTPUT_OPEN || 1427 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1428 if (sshbuf_len(c->output) > 0) 1429 c->io_want |= SSH_CHAN_IO_WFD; 1430 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1431 chan_obuf_empty(ssh, c); 1432 } 1433 } 1434 1435 /* try to decode a socks4 header */ 1436 static int 1437 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1438 { 1439 const u_char *p; 1440 char *host; 1441 u_int len, have, i, found, need; 1442 char username[256]; 1443 struct { 1444 u_int8_t version; 1445 u_int8_t command; 1446 u_int16_t dest_port; 1447 struct in_addr dest_addr; 1448 } s4_req, s4_rsp; 1449 int r; 1450 1451 debug2("channel %d: decode socks4", c->self); 1452 1453 have = sshbuf_len(input); 1454 len = sizeof(s4_req); 1455 if (have < len) 1456 return 0; 1457 p = sshbuf_ptr(input); 1458 1459 need = 1; 1460 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1461 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1462 debug2("channel %d: socks4a request", c->self); 1463 /* ... and needs an extra string (the hostname) */ 1464 need = 2; 1465 } 1466 /* Check for terminating NUL on the string(s) */ 1467 for (found = 0, i = len; i < have; i++) { 1468 if (p[i] == '\0') { 1469 found++; 1470 if (found == need) 1471 break; 1472 } 1473 if (i > 1024) { 1474 /* the peer is probably sending garbage */ 1475 debug("channel %d: decode socks4: too long", 1476 c->self); 1477 return -1; 1478 } 1479 } 1480 if (found < need) 1481 return 0; 1482 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1483 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1484 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1485 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1486 debug_r(r, "channels %d: decode socks4", c->self); 1487 return -1; 1488 } 1489 have = sshbuf_len(input); 1490 p = sshbuf_ptr(input); 1491 if (memchr(p, '\0', have) == NULL) { 1492 error("channel %d: decode socks4: unterminated user", c->self); 1493 return -1; 1494 } 1495 len = strlen(p); 1496 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1497 len++; /* trailing '\0' */ 1498 strlcpy(username, p, sizeof(username)); 1499 if ((r = sshbuf_consume(input, len)) != 0) 1500 fatal_fr(r, "channel %d: consume", c->self); 1501 free(c->path); 1502 c->path = NULL; 1503 if (need == 1) { /* SOCKS4: one string */ 1504 host = inet_ntoa(s4_req.dest_addr); 1505 c->path = xstrdup(host); 1506 } else { /* SOCKS4A: two strings */ 1507 have = sshbuf_len(input); 1508 p = sshbuf_ptr(input); 1509 if (memchr(p, '\0', have) == NULL) { 1510 error("channel %d: decode socks4a: host not nul " 1511 "terminated", c->self); 1512 return -1; 1513 } 1514 len = strlen(p); 1515 debug2("channel %d: decode socks4a: host %s/%d", 1516 c->self, p, len); 1517 len++; /* trailing '\0' */ 1518 if (len > NI_MAXHOST) { 1519 error("channel %d: hostname \"%.100s\" too long", 1520 c->self, p); 1521 return -1; 1522 } 1523 c->path = xstrdup(p); 1524 if ((r = sshbuf_consume(input, len)) != 0) 1525 fatal_fr(r, "channel %d: consume", c->self); 1526 } 1527 c->host_port = ntohs(s4_req.dest_port); 1528 1529 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1530 c->self, c->path, c->host_port, s4_req.command); 1531 1532 if (s4_req.command != 1) { 1533 debug("channel %d: cannot handle: %s cn %d", 1534 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1535 return -1; 1536 } 1537 s4_rsp.version = 0; /* vn: 0 for reply */ 1538 s4_rsp.command = 90; /* cd: req granted */ 1539 s4_rsp.dest_port = 0; /* ignored */ 1540 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1541 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1542 fatal_fr(r, "channel %d: append reply", c->self); 1543 return 1; 1544 } 1545 1546 /* try to decode a socks5 header */ 1547 #define SSH_SOCKS5_AUTHDONE 0x1000 1548 #define SSH_SOCKS5_NOAUTH 0x00 1549 #define SSH_SOCKS5_IPV4 0x01 1550 #define SSH_SOCKS5_DOMAIN 0x03 1551 #define SSH_SOCKS5_IPV6 0x04 1552 #define SSH_SOCKS5_CONNECT 0x01 1553 #define SSH_SOCKS5_SUCCESS 0x00 1554 1555 static int 1556 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1557 { 1558 /* XXX use get/put_u8 instead of trusting struct padding */ 1559 struct { 1560 u_int8_t version; 1561 u_int8_t command; 1562 u_int8_t reserved; 1563 u_int8_t atyp; 1564 } s5_req, s5_rsp; 1565 u_int16_t dest_port; 1566 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1567 const u_char *p; 1568 u_int have, need, i, found, nmethods, addrlen, af; 1569 int r; 1570 1571 debug2("channel %d: decode socks5", c->self); 1572 p = sshbuf_ptr(input); 1573 if (p[0] != 0x05) 1574 return -1; 1575 have = sshbuf_len(input); 1576 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1577 /* format: ver | nmethods | methods */ 1578 if (have < 2) 1579 return 0; 1580 nmethods = p[1]; 1581 if (have < nmethods + 2) 1582 return 0; 1583 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1584 for (found = 0, i = 2; i < nmethods + 2; i++) { 1585 if (p[i] == SSH_SOCKS5_NOAUTH) { 1586 found = 1; 1587 break; 1588 } 1589 } 1590 if (!found) { 1591 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1592 c->self); 1593 return -1; 1594 } 1595 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1596 fatal_fr(r, "channel %d: consume", c->self); 1597 /* version, method */ 1598 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1599 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1600 fatal_fr(r, "channel %d: append reply", c->self); 1601 c->flags |= SSH_SOCKS5_AUTHDONE; 1602 debug2("channel %d: socks5 auth done", c->self); 1603 return 0; /* need more */ 1604 } 1605 debug2("channel %d: socks5 post auth", c->self); 1606 if (have < sizeof(s5_req)+1) 1607 return 0; /* need more */ 1608 memcpy(&s5_req, p, sizeof(s5_req)); 1609 if (s5_req.version != 0x05 || 1610 s5_req.command != SSH_SOCKS5_CONNECT || 1611 s5_req.reserved != 0x00) { 1612 debug2("channel %d: only socks5 connect supported", c->self); 1613 return -1; 1614 } 1615 switch (s5_req.atyp){ 1616 case SSH_SOCKS5_IPV4: 1617 addrlen = 4; 1618 af = AF_INET; 1619 break; 1620 case SSH_SOCKS5_DOMAIN: 1621 addrlen = p[sizeof(s5_req)]; 1622 af = -1; 1623 break; 1624 case SSH_SOCKS5_IPV6: 1625 addrlen = 16; 1626 af = AF_INET6; 1627 break; 1628 default: 1629 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1630 return -1; 1631 } 1632 need = sizeof(s5_req) + addrlen + 2; 1633 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1634 need++; 1635 if (have < need) 1636 return 0; 1637 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1638 fatal_fr(r, "channel %d: consume", c->self); 1639 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1640 /* host string length */ 1641 if ((r = sshbuf_consume(input, 1)) != 0) 1642 fatal_fr(r, "channel %d: consume", c->self); 1643 } 1644 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1645 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1646 debug_r(r, "channel %d: parse addr/port", c->self); 1647 return -1; 1648 } 1649 dest_addr[addrlen] = '\0'; 1650 free(c->path); 1651 c->path = NULL; 1652 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1653 if (addrlen >= NI_MAXHOST) { 1654 error("channel %d: dynamic request: socks5 hostname " 1655 "\"%.100s\" too long", c->self, dest_addr); 1656 return -1; 1657 } 1658 c->path = xstrdup(dest_addr); 1659 } else { 1660 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1661 return -1; 1662 c->path = xstrdup(ntop); 1663 } 1664 c->host_port = ntohs(dest_port); 1665 1666 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1667 c->self, c->path, c->host_port, s5_req.command); 1668 1669 s5_rsp.version = 0x05; 1670 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1671 s5_rsp.reserved = 0; /* ignored */ 1672 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1673 dest_port = 0; /* ignored */ 1674 1675 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1676 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1677 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1678 fatal_fr(r, "channel %d: append reply", c->self); 1679 return 1; 1680 } 1681 1682 Channel * 1683 channel_connect_stdio_fwd(struct ssh *ssh, 1684 const char *host_to_connect, int port_to_connect, 1685 int in, int out, int nonblock) 1686 { 1687 Channel *c; 1688 1689 debug_f("%s:%d", host_to_connect, port_to_connect); 1690 1691 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1692 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1693 0, "stdio-forward", nonblock); 1694 1695 c->path = xstrdup(host_to_connect); 1696 c->host_port = port_to_connect; 1697 c->listening_port = 0; 1698 c->force_drain = 1; 1699 1700 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1701 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1702 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1703 1704 return c; 1705 } 1706 1707 /* dynamic port forwarding */ 1708 static void 1709 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1710 { 1711 const u_char *p; 1712 u_int have; 1713 int ret; 1714 1715 c->io_want = 0; 1716 have = sshbuf_len(c->input); 1717 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1718 /* sshbuf_dump(c->input, stderr); */ 1719 /* check if the fixed size part of the packet is in buffer. */ 1720 if (have < 3) { 1721 /* need more */ 1722 c->io_want |= SSH_CHAN_IO_RFD; 1723 return; 1724 } 1725 /* try to guess the protocol */ 1726 p = sshbuf_ptr(c->input); 1727 /* XXX sshbuf_peek_u8? */ 1728 switch (p[0]) { 1729 case 0x04: 1730 ret = channel_decode_socks4(c, c->input, c->output); 1731 break; 1732 case 0x05: 1733 ret = channel_decode_socks5(c, c->input, c->output); 1734 break; 1735 default: 1736 ret = -1; 1737 break; 1738 } 1739 if (ret < 0) { 1740 chan_mark_dead(ssh, c); 1741 } else if (ret == 0) { 1742 debug2("channel %d: pre_dynamic: need more", c->self); 1743 /* need more */ 1744 c->io_want |= SSH_CHAN_IO_RFD; 1745 if (sshbuf_len(c->output)) 1746 c->io_want |= SSH_CHAN_IO_WFD; 1747 } else { 1748 /* switch to the next state */ 1749 c->type = SSH_CHANNEL_OPENING; 1750 port_open_helper(ssh, c, "direct-tcpip"); 1751 } 1752 } 1753 1754 /* simulate read-error */ 1755 static void 1756 rdynamic_close(struct ssh *ssh, Channel *c) 1757 { 1758 c->type = SSH_CHANNEL_OPEN; 1759 channel_force_close(ssh, c, 0); 1760 } 1761 1762 /* reverse dynamic port forwarding */ 1763 static void 1764 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1765 { 1766 const u_char *p; 1767 u_int have, len; 1768 int r, ret; 1769 1770 have = sshbuf_len(c->output); 1771 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1772 /* sshbuf_dump(c->output, stderr); */ 1773 /* EOF received */ 1774 if (c->flags & CHAN_EOF_RCVD) { 1775 if ((r = sshbuf_consume(c->output, have)) != 0) 1776 fatal_fr(r, "channel %d: consume", c->self); 1777 rdynamic_close(ssh, c); 1778 return; 1779 } 1780 /* check if the fixed size part of the packet is in buffer. */ 1781 if (have < 3) 1782 return; 1783 /* try to guess the protocol */ 1784 p = sshbuf_ptr(c->output); 1785 switch (p[0]) { 1786 case 0x04: 1787 /* switch input/output for reverse forwarding */ 1788 ret = channel_decode_socks4(c, c->output, c->input); 1789 break; 1790 case 0x05: 1791 ret = channel_decode_socks5(c, c->output, c->input); 1792 break; 1793 default: 1794 ret = -1; 1795 break; 1796 } 1797 if (ret < 0) { 1798 rdynamic_close(ssh, c); 1799 } else if (ret == 0) { 1800 debug2("channel %d: pre_rdynamic: need more", c->self); 1801 /* send socks request to peer */ 1802 len = sshbuf_len(c->input); 1803 if (len > 0 && len < c->remote_window) { 1804 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1805 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1806 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1807 (r = sshpkt_send(ssh)) != 0) { 1808 fatal_fr(r, "channel %i: rdynamic", c->self); 1809 } 1810 if ((r = sshbuf_consume(c->input, len)) != 0) 1811 fatal_fr(r, "channel %d: consume", c->self); 1812 c->remote_window -= len; 1813 } 1814 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1815 /* the connect failed */ 1816 rdynamic_close(ssh, c); 1817 } 1818 } 1819 1820 /* This is our fake X11 server socket. */ 1821 static void 1822 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1823 { 1824 Channel *nc; 1825 struct sockaddr_storage addr; 1826 int r, newsock, oerrno, remote_port; 1827 socklen_t addrlen; 1828 char buf[16384], *remote_ipaddr; 1829 1830 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1831 return; 1832 1833 debug("X11 connection requested."); 1834 addrlen = sizeof(addr); 1835 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1836 if (c->single_connection) { 1837 oerrno = errno; 1838 debug2("single_connection: closing X11 listener."); 1839 channel_close_fd(ssh, c, &c->sock); 1840 chan_mark_dead(ssh, c); 1841 errno = oerrno; 1842 } 1843 if (newsock == -1) { 1844 if (errno != EINTR && errno != EWOULDBLOCK && 1845 errno != ECONNABORTED) 1846 error("accept: %.100s", strerror(errno)); 1847 if (errno == EMFILE || errno == ENFILE) 1848 c->notbefore = monotime() + 1; 1849 return; 1850 } 1851 set_nodelay(newsock); 1852 remote_ipaddr = get_peer_ipaddr(newsock); 1853 remote_port = get_peer_port(newsock); 1854 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1855 remote_ipaddr, remote_port); 1856 1857 nc = channel_new(ssh, "x11-connection", 1858 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1859 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1860 open_preamble(ssh, __func__, nc, "x11"); 1861 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1862 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1863 fatal_fr(r, "channel %i: reply", c->self); 1864 } 1865 if ((r = sshpkt_send(ssh)) != 0) 1866 fatal_fr(r, "channel %i: send", c->self); 1867 free(remote_ipaddr); 1868 } 1869 1870 static void 1871 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1872 { 1873 char *local_ipaddr = get_local_ipaddr(c->sock); 1874 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1875 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1876 int remote_port = get_peer_port(c->sock); 1877 int r; 1878 1879 if (remote_port == -1) { 1880 /* Fake addr/port to appease peers that validate it (Tectia) */ 1881 free(remote_ipaddr); 1882 remote_ipaddr = xstrdup("127.0.0.1"); 1883 remote_port = 65535; 1884 } 1885 1886 free(c->remote_name); 1887 xasprintf(&c->remote_name, 1888 "%s: listening port %d for %.100s port %d, " 1889 "connect from %.200s port %d to %.100s port %d", 1890 rtype, c->listening_port, c->path, c->host_port, 1891 remote_ipaddr, remote_port, local_ipaddr, local_port); 1892 1893 open_preamble(ssh, __func__, c, rtype); 1894 if (strcmp(rtype, "direct-tcpip") == 0) { 1895 /* target host, port */ 1896 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1897 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1898 fatal_fr(r, "channel %i: reply", c->self); 1899 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1900 /* target path */ 1901 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1902 fatal_fr(r, "channel %i: reply", c->self); 1903 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1904 /* listen path */ 1905 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1906 fatal_fr(r, "channel %i: reply", c->self); 1907 } else { 1908 /* listen address, port */ 1909 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1910 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1911 fatal_fr(r, "channel %i: reply", c->self); 1912 } 1913 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1914 /* reserved for future owner/mode info */ 1915 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1916 fatal_fr(r, "channel %i: reply", c->self); 1917 } else { 1918 /* originator host and port */ 1919 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1920 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1921 fatal_fr(r, "channel %i: reply", c->self); 1922 } 1923 if ((r = sshpkt_send(ssh)) != 0) 1924 fatal_fr(r, "channel %i: send", c->self); 1925 free(remote_ipaddr); 1926 free(local_ipaddr); 1927 } 1928 1929 void 1930 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1931 { 1932 ssh->chanctxt->x11_refuse_time = refuse_time; 1933 } 1934 1935 /* 1936 * This socket is listening for connections to a forwarded TCP/IP port. 1937 */ 1938 static void 1939 channel_post_port_listener(struct ssh *ssh, Channel *c) 1940 { 1941 Channel *nc; 1942 struct sockaddr_storage addr; 1943 int newsock, nextstate; 1944 socklen_t addrlen; 1945 char *rtype; 1946 1947 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1948 return; 1949 1950 debug("Connection to port %d forwarding to %.100s port %d requested.", 1951 c->listening_port, c->path, c->host_port); 1952 1953 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1954 nextstate = SSH_CHANNEL_OPENING; 1955 rtype = "forwarded-tcpip"; 1956 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1957 nextstate = SSH_CHANNEL_OPENING; 1958 rtype = "forwarded-streamlocal@openssh.com"; 1959 } else if (c->host_port == PORT_STREAMLOCAL) { 1960 nextstate = SSH_CHANNEL_OPENING; 1961 rtype = "direct-streamlocal@openssh.com"; 1962 } else if (c->host_port == 0) { 1963 nextstate = SSH_CHANNEL_DYNAMIC; 1964 rtype = "dynamic-tcpip"; 1965 } else { 1966 nextstate = SSH_CHANNEL_OPENING; 1967 rtype = "direct-tcpip"; 1968 } 1969 1970 addrlen = sizeof(addr); 1971 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1972 if (newsock == -1) { 1973 if (errno != EINTR && errno != EWOULDBLOCK && 1974 errno != ECONNABORTED) 1975 error("accept: %.100s", strerror(errno)); 1976 if (errno == EMFILE || errno == ENFILE) 1977 c->notbefore = monotime() + 1; 1978 return; 1979 } 1980 if (c->host_port != PORT_STREAMLOCAL) 1981 set_nodelay(newsock); 1982 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1983 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1984 nc->listening_port = c->listening_port; 1985 nc->host_port = c->host_port; 1986 if (c->path != NULL) 1987 nc->path = xstrdup(c->path); 1988 1989 if (nextstate != SSH_CHANNEL_DYNAMIC) 1990 port_open_helper(ssh, nc, rtype); 1991 } 1992 1993 /* 1994 * This is the authentication agent socket listening for connections from 1995 * clients. 1996 */ 1997 static void 1998 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1999 { 2000 Channel *nc; 2001 int r, newsock; 2002 struct sockaddr_storage addr; 2003 socklen_t addrlen; 2004 2005 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2006 return; 2007 2008 addrlen = sizeof(addr); 2009 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2010 if (newsock == -1) { 2011 error("accept from auth socket: %.100s", strerror(errno)); 2012 if (errno == EMFILE || errno == ENFILE) 2013 c->notbefore = monotime() + 1; 2014 return; 2015 } 2016 nc = channel_new(ssh, "agent-connection", 2017 SSH_CHANNEL_OPENING, newsock, newsock, -1, 2018 c->local_window_max, c->local_maxpacket, 2019 0, "accepted auth socket", 1); 2020 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 2021 if ((r = sshpkt_send(ssh)) != 0) 2022 fatal_fr(r, "channel %i", c->self); 2023 } 2024 2025 static void 2026 channel_post_connecting(struct ssh *ssh, Channel *c) 2027 { 2028 int err = 0, sock, isopen, r; 2029 socklen_t sz = sizeof(err); 2030 2031 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2032 return; 2033 if (!c->have_remote_id) 2034 fatal_f("channel %d: no remote id", c->self); 2035 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2036 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2037 2038 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2039 err = errno; 2040 error("getsockopt SO_ERROR failed"); 2041 } 2042 2043 if (err == 0) { 2044 /* Non-blocking connection completed */ 2045 debug("channel %d: connected to %s port %d", 2046 c->self, c->connect_ctx.host, c->connect_ctx.port); 2047 channel_connect_ctx_free(&c->connect_ctx); 2048 c->type = SSH_CHANNEL_OPEN; 2049 channel_set_used_time(ssh, c); 2050 if (isopen) { 2051 /* no message necessary */ 2052 } else { 2053 if ((r = sshpkt_start(ssh, 2054 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2055 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2056 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2057 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2058 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2059 (r = sshpkt_send(ssh)) != 0) 2060 fatal_fr(r, "channel %i open confirm", c->self); 2061 } 2062 return; 2063 } 2064 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2065 return; 2066 2067 /* Non-blocking connection failed */ 2068 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2069 2070 /* Try next address, if any */ 2071 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2072 /* Exhausted all addresses for this destination */ 2073 error("connect_to %.100s port %d: failed.", 2074 c->connect_ctx.host, c->connect_ctx.port); 2075 channel_connect_ctx_free(&c->connect_ctx); 2076 if (isopen) { 2077 rdynamic_close(ssh, c); 2078 } else { 2079 if ((r = sshpkt_start(ssh, 2080 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2081 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2082 (r = sshpkt_put_u32(ssh, 2083 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2084 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2085 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2086 (r = sshpkt_send(ssh)) != 0) 2087 fatal_fr(r, "channel %i: failure", c->self); 2088 chan_mark_dead(ssh, c); 2089 } 2090 } 2091 2092 /* New non-blocking connection in progress */ 2093 close(c->sock); 2094 c->sock = c->rfd = c->wfd = sock; 2095 } 2096 2097 static int 2098 channel_handle_rfd(struct ssh *ssh, Channel *c) 2099 { 2100 char buf[CHAN_RBUF]; 2101 ssize_t len; 2102 int r; 2103 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2104 2105 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2106 return 1; /* Shouldn't happen */ 2107 if ((avail = sshbuf_avail(c->input)) == 0) 2108 return 1; /* Shouldn't happen */ 2109 2110 /* 2111 * For "simple" channels (i.e. not datagram or filtered), we can 2112 * read directly to the channel buffer. 2113 */ 2114 if (c->input_filter == NULL && !c->datagram) { 2115 /* Only OPEN channels have valid rwin */ 2116 if (c->type == SSH_CHANNEL_OPEN) { 2117 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2118 return 1; /* shouldn't happen */ 2119 if (maxlen > c->remote_window - have) 2120 maxlen = c->remote_window - have; 2121 } 2122 if (maxlen > avail) 2123 maxlen = avail; 2124 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2125 if (errno == EINTR || errno == EAGAIN) 2126 return 1; 2127 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2128 c->self, c->rfd, maxlen, ssh_err(r)); 2129 goto rfail; 2130 } 2131 if (nr != 0) 2132 channel_set_used_time(ssh, c); 2133 return 1; 2134 } 2135 2136 len = read(c->rfd, buf, sizeof(buf)); 2137 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2138 return 1; 2139 if (len <= 0) { 2140 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2141 c->self, c->rfd, len, 2142 len == 0 ? "closed" : strerror(errno)); 2143 rfail: 2144 if (c->type != SSH_CHANNEL_OPEN) { 2145 debug2("channel %d: not open", c->self); 2146 chan_mark_dead(ssh, c); 2147 return -1; 2148 } else { 2149 chan_read_failed(ssh, c); 2150 } 2151 return -1; 2152 } 2153 channel_set_used_time(ssh, c); 2154 if (c->input_filter != NULL) { 2155 if (c->input_filter(ssh, c, buf, len) == -1) { 2156 debug2("channel %d: filter stops", c->self); 2157 chan_read_failed(ssh, c); 2158 } 2159 } else if (c->datagram) { 2160 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2161 fatal_fr(r, "channel %i: put datagram", c->self); 2162 } 2163 return 1; 2164 } 2165 2166 static int 2167 channel_handle_wfd(struct ssh *ssh, Channel *c) 2168 { 2169 struct termios tio; 2170 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2171 size_t dlen, olen = 0; 2172 int r, len; 2173 2174 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2175 return 1; 2176 if (sshbuf_len(c->output) == 0) 2177 return 1; 2178 2179 /* Send buffered output data to the socket. */ 2180 olen = sshbuf_len(c->output); 2181 if (c->output_filter != NULL) { 2182 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2183 debug2("channel %d: filter stops", c->self); 2184 if (c->type != SSH_CHANNEL_OPEN) 2185 chan_mark_dead(ssh, c); 2186 else 2187 chan_write_failed(ssh, c); 2188 return -1; 2189 } 2190 } else if (c->datagram) { 2191 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2192 fatal_fr(r, "channel %i: get datagram", c->self); 2193 buf = data; 2194 } else { 2195 buf = data = sshbuf_mutable_ptr(c->output); 2196 dlen = sshbuf_len(c->output); 2197 } 2198 2199 if (c->datagram) { 2200 /* ignore truncated writes, datagrams might get lost */ 2201 len = write(c->wfd, buf, dlen); 2202 free(data); 2203 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2204 return 1; 2205 if (len <= 0) 2206 goto write_fail; 2207 goto out; 2208 } 2209 2210 len = write(c->wfd, buf, dlen); 2211 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2212 return 1; 2213 if (len <= 0) { 2214 write_fail: 2215 if (c->type != SSH_CHANNEL_OPEN) { 2216 debug2("channel %d: not open", c->self); 2217 chan_mark_dead(ssh, c); 2218 return -1; 2219 } else { 2220 chan_write_failed(ssh, c); 2221 } 2222 return -1; 2223 } 2224 channel_set_used_time(ssh, c); 2225 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2226 if (tcgetattr(c->wfd, &tio) == 0 && 2227 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2228 /* 2229 * Simulate echo to reduce the impact of 2230 * traffic analysis. We need to match the 2231 * size of a SSH2_MSG_CHANNEL_DATA message 2232 * (4 byte channel id + buf) 2233 */ 2234 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2235 (r = sshpkt_send(ssh)) != 0) 2236 fatal_fr(r, "channel %i: ignore", c->self); 2237 } 2238 } 2239 if ((r = sshbuf_consume(c->output, len)) != 0) 2240 fatal_fr(r, "channel %i: consume", c->self); 2241 out: 2242 c->local_consumed += olen - sshbuf_len(c->output); 2243 2244 return 1; 2245 } 2246 2247 static int 2248 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2249 { 2250 int r; 2251 ssize_t len; 2252 2253 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2254 return 1; 2255 if (sshbuf_len(c->extended) == 0) 2256 return 1; 2257 2258 len = write(c->efd, sshbuf_ptr(c->extended), 2259 sshbuf_len(c->extended)); 2260 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2261 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2262 return 1; 2263 if (len <= 0) { 2264 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2265 channel_close_fd(ssh, c, &c->efd); 2266 } else { 2267 if ((r = sshbuf_consume(c->extended, len)) != 0) 2268 fatal_fr(r, "channel %i: consume", c->self); 2269 c->local_consumed += len; 2270 channel_set_used_time(ssh, c); 2271 } 2272 return 1; 2273 } 2274 2275 static int 2276 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2277 { 2278 char buf[CHAN_RBUF]; 2279 int r; 2280 ssize_t len; 2281 2282 if ((c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2283 return 1; 2284 2285 len = read(c->efd, buf, sizeof(buf)); 2286 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2287 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2288 return 1; 2289 if (len <= 0) { 2290 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2291 channel_close_fd(ssh, c, &c->efd); 2292 return 1; 2293 } 2294 channel_set_used_time(ssh, c); 2295 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2296 debug3("channel %d: discard efd", c->self); 2297 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2298 fatal_fr(r, "channel %i: append", c->self); 2299 return 1; 2300 } 2301 2302 static int 2303 channel_handle_efd(struct ssh *ssh, Channel *c) 2304 { 2305 if (c->efd == -1) 2306 return 1; 2307 2308 /** XXX handle drain efd, too */ 2309 2310 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2311 return channel_handle_efd_write(ssh, c); 2312 else if (c->extended_usage == CHAN_EXTENDED_READ || 2313 c->extended_usage == CHAN_EXTENDED_IGNORE) 2314 return channel_handle_efd_read(ssh, c); 2315 2316 return 1; 2317 } 2318 2319 static int 2320 channel_check_window(struct ssh *ssh, Channel *c) 2321 { 2322 int r; 2323 2324 if (c->type == SSH_CHANNEL_OPEN && 2325 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2326 ((c->local_window_max - c->local_window > 2327 c->local_maxpacket*3) || 2328 c->local_window < c->local_window_max/2) && 2329 c->local_consumed > 0) { 2330 if (!c->have_remote_id) 2331 fatal_f("channel %d: no remote id", c->self); 2332 if ((r = sshpkt_start(ssh, 2333 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2334 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2335 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2336 (r = sshpkt_send(ssh)) != 0) { 2337 fatal_fr(r, "channel %i", c->self); 2338 } 2339 debug2("channel %d: window %d sent adjust %d", c->self, 2340 c->local_window, c->local_consumed); 2341 c->local_window += c->local_consumed; 2342 c->local_consumed = 0; 2343 } 2344 return 1; 2345 } 2346 2347 static void 2348 channel_post_open(struct ssh *ssh, Channel *c) 2349 { 2350 channel_handle_rfd(ssh, c); 2351 channel_handle_wfd(ssh, c); 2352 channel_handle_efd(ssh, c); 2353 channel_check_window(ssh, c); 2354 } 2355 2356 static u_int 2357 read_mux(struct ssh *ssh, Channel *c, u_int need) 2358 { 2359 char buf[CHAN_RBUF]; 2360 ssize_t len; 2361 u_int rlen; 2362 int r; 2363 2364 if (sshbuf_len(c->input) < need) { 2365 rlen = need - sshbuf_len(c->input); 2366 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2367 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2368 return sshbuf_len(c->input); 2369 if (len <= 0) { 2370 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2371 c->self, c->rfd, len); 2372 chan_read_failed(ssh, c); 2373 return 0; 2374 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2375 fatal_fr(r, "channel %i: append", c->self); 2376 } 2377 return sshbuf_len(c->input); 2378 } 2379 2380 static void 2381 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2382 { 2383 u_int need; 2384 2385 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2386 return; 2387 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2388 return; 2389 if (c->mux_pause) 2390 return; 2391 2392 /* 2393 * Don't not read past the precise end of packets to 2394 * avoid disrupting fd passing. 2395 */ 2396 if (read_mux(ssh, c, 4) < 4) /* read header */ 2397 return; 2398 /* XXX sshbuf_peek_u32 */ 2399 need = PEEK_U32(sshbuf_ptr(c->input)); 2400 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2401 if (need > CHANNEL_MUX_MAX_PACKET) { 2402 debug2("channel %d: packet too big %u > %u", 2403 c->self, CHANNEL_MUX_MAX_PACKET, need); 2404 chan_rcvd_oclose(ssh, c); 2405 return; 2406 } 2407 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2408 return; 2409 if (c->mux_rcb(ssh, c) != 0) { 2410 debug("channel %d: mux_rcb failed", c->self); 2411 chan_mark_dead(ssh, c); 2412 return; 2413 } 2414 } 2415 2416 static void 2417 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2418 { 2419 ssize_t len; 2420 int r; 2421 2422 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2423 return; 2424 if (sshbuf_len(c->output) == 0) 2425 return; 2426 2427 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2428 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2429 return; 2430 if (len <= 0) { 2431 chan_mark_dead(ssh, c); 2432 return; 2433 } 2434 if ((r = sshbuf_consume(c->output, len)) != 0) 2435 fatal_fr(r, "channel %i: consume", c->self); 2436 } 2437 2438 static void 2439 channel_post_mux_client(struct ssh *ssh, Channel *c) 2440 { 2441 channel_post_mux_client_read(ssh, c); 2442 channel_post_mux_client_write(ssh, c); 2443 } 2444 2445 static void 2446 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2447 { 2448 Channel *nc; 2449 struct sockaddr_storage addr; 2450 socklen_t addrlen; 2451 int newsock; 2452 uid_t euid; 2453 gid_t egid; 2454 2455 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2456 return; 2457 2458 debug("multiplexing control connection"); 2459 2460 /* 2461 * Accept connection on control socket 2462 */ 2463 memset(&addr, 0, sizeof(addr)); 2464 addrlen = sizeof(addr); 2465 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2466 &addrlen)) == -1) { 2467 error_f("accept: %s", strerror(errno)); 2468 if (errno == EMFILE || errno == ENFILE) 2469 c->notbefore = monotime() + 1; 2470 return; 2471 } 2472 2473 if (getpeereid(newsock, &euid, &egid) == -1) { 2474 error_f("getpeereid failed: %s", strerror(errno)); 2475 close(newsock); 2476 return; 2477 } 2478 if ((euid != 0) && (getuid() != euid)) { 2479 error("multiplex uid mismatch: peer euid %u != uid %u", 2480 (u_int)euid, (u_int)getuid()); 2481 close(newsock); 2482 return; 2483 } 2484 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2485 newsock, newsock, -1, c->local_window_max, 2486 c->local_maxpacket, 0, "mux-control", 1); 2487 nc->mux_rcb = c->mux_rcb; 2488 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2489 /* establish state */ 2490 nc->mux_rcb(ssh, nc); 2491 /* mux state transitions must not elicit protocol messages */ 2492 nc->flags |= CHAN_LOCAL; 2493 } 2494 2495 static void 2496 channel_handler_init(struct ssh_channels *sc) 2497 { 2498 chan_fn **pre, **post; 2499 2500 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2501 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2502 fatal_f("allocation failed"); 2503 2504 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2505 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2506 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2507 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2508 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2509 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2510 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2511 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2512 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2513 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2514 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2515 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2516 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2517 2518 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2519 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2520 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2521 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2522 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2523 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2524 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2525 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2526 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2527 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2528 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2529 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2530 2531 sc->channel_pre = pre; 2532 sc->channel_post = post; 2533 } 2534 2535 /* gc dead channels */ 2536 static void 2537 channel_garbage_collect(struct ssh *ssh, Channel *c) 2538 { 2539 if (c == NULL) 2540 return; 2541 if (c->detach_user != NULL) { 2542 if (!chan_is_dead(ssh, c, c->detach_close)) 2543 return; 2544 2545 debug2("channel %d: gc: notify user", c->self); 2546 c->detach_user(ssh, c->self, 0, NULL); 2547 /* if we still have a callback */ 2548 if (c->detach_user != NULL) 2549 return; 2550 debug2("channel %d: gc: user detached", c->self); 2551 } 2552 if (!chan_is_dead(ssh, c, 1)) 2553 return; 2554 debug2("channel %d: garbage collecting", c->self); 2555 channel_free(ssh, c); 2556 } 2557 2558 enum channel_table { CHAN_PRE, CHAN_POST }; 2559 2560 static void 2561 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2562 { 2563 struct ssh_channels *sc = ssh->chanctxt; 2564 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2565 u_int i, oalloc; 2566 Channel *c; 2567 time_t now; 2568 2569 now = monotime(); 2570 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2571 c = sc->channels[i]; 2572 if (c == NULL) 2573 continue; 2574 /* Try to keep IO going while rekeying */ 2575 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2576 continue; 2577 if (c->delayed) { 2578 if (table == CHAN_PRE) 2579 c->delayed = 0; 2580 else 2581 continue; 2582 } 2583 if (ftab[c->type] != NULL) { 2584 if (table == CHAN_PRE && c->type == SSH_CHANNEL_OPEN && 2585 channel_get_expiry(ssh, c) != 0 && 2586 now >= channel_get_expiry(ssh, c)) { 2587 /* channel closed for inactivity */ 2588 verbose("channel %d: closing after %u seconds " 2589 "of inactivity", c->self, 2590 c->inactive_deadline); 2591 channel_force_close(ssh, c, 1); 2592 } else if (c->notbefore <= now) { 2593 /* Run handlers that are not paused. */ 2594 (*ftab[c->type])(ssh, c); 2595 /* inactivity timeouts must interrupt poll() */ 2596 if (timeout != NULL && 2597 c->type == SSH_CHANNEL_OPEN && 2598 channel_get_expiry(ssh, c) != 0) { 2599 ptimeout_deadline_monotime(timeout, 2600 channel_get_expiry(ssh, c)); 2601 } 2602 } else if (timeout != NULL) { 2603 /* 2604 * Arrange for poll() wakeup when channel pause 2605 * timer expires. 2606 */ 2607 ptimeout_deadline_monotime(timeout, 2608 c->notbefore); 2609 } 2610 } 2611 channel_garbage_collect(ssh, c); 2612 } 2613 } 2614 2615 /* 2616 * Create sockets before preparing IO. 2617 * This is necessary for things that need to happen after reading 2618 * the network-input but need to be completed before IO event setup, e.g. 2619 * because they may create new channels. 2620 */ 2621 static void 2622 channel_before_prepare_io(struct ssh *ssh) 2623 { 2624 struct ssh_channels *sc = ssh->chanctxt; 2625 Channel *c; 2626 u_int i, oalloc; 2627 2628 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2629 c = sc->channels[i]; 2630 if (c == NULL) 2631 continue; 2632 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2633 channel_before_prepare_io_rdynamic(ssh, c); 2634 } 2635 } 2636 2637 static void 2638 dump_channel_poll(const char *func, const char *what, Channel *c, 2639 u_int pollfd_offset, struct pollfd *pfd) 2640 { 2641 #ifdef DEBUG_CHANNEL_POLL 2642 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2643 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2644 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2645 c->rfd, c->wfd, c->efd, c->sock, 2646 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2647 c->io_want, c->io_ready, 2648 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2649 #endif 2650 } 2651 2652 /* Prepare pollfd entries for a single channel */ 2653 static void 2654 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2655 struct pollfd *pfd, u_int npfd) 2656 { 2657 u_int ev, p = *next_pollfd; 2658 2659 if (c == NULL) 2660 return; 2661 if (p + 4 > npfd) { 2662 /* Shouldn't happen */ 2663 fatal_f("channel %d: bad pfd offset %u (max %u)", 2664 c->self, p, npfd); 2665 } 2666 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2667 /* 2668 * prepare c->rfd 2669 * 2670 * This is a special case, since c->rfd might be the same as 2671 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2672 * IO too. 2673 */ 2674 if (c->rfd != -1) { 2675 ev = 0; 2676 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2677 ev |= POLLIN; 2678 /* rfd == wfd */ 2679 if (c->wfd == c->rfd) { 2680 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2681 ev |= POLLOUT; 2682 } 2683 /* rfd == efd */ 2684 if (c->efd == c->rfd) { 2685 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2686 ev |= POLLIN; 2687 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2688 ev |= POLLOUT; 2689 } 2690 /* rfd == sock */ 2691 if (c->sock == c->rfd) { 2692 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2693 ev |= POLLIN; 2694 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2695 ev |= POLLOUT; 2696 } 2697 /* Pack a pfd entry if any event armed for this fd */ 2698 if (ev != 0) { 2699 c->pfds[0] = p; 2700 pfd[p].fd = c->rfd; 2701 pfd[p].events = ev; 2702 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2703 p++; 2704 } 2705 } 2706 /* prepare c->wfd if wanting IO and not already handled above */ 2707 if (c->wfd != -1 && c->rfd != c->wfd) { 2708 ev = 0; 2709 if ((c->io_want & SSH_CHAN_IO_WFD)) 2710 ev |= POLLOUT; 2711 /* Pack a pfd entry if any event armed for this fd */ 2712 if (ev != 0) { 2713 c->pfds[1] = p; 2714 pfd[p].fd = c->wfd; 2715 pfd[p].events = ev; 2716 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2717 p++; 2718 } 2719 } 2720 /* prepare c->efd if wanting IO and not already handled above */ 2721 if (c->efd != -1 && c->rfd != c->efd) { 2722 ev = 0; 2723 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2724 ev |= POLLIN; 2725 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2726 ev |= POLLOUT; 2727 /* Pack a pfd entry if any event armed for this fd */ 2728 if (ev != 0) { 2729 c->pfds[2] = p; 2730 pfd[p].fd = c->efd; 2731 pfd[p].events = ev; 2732 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2733 p++; 2734 } 2735 } 2736 /* prepare c->sock if wanting IO and not already handled above */ 2737 if (c->sock != -1 && c->rfd != c->sock) { 2738 ev = 0; 2739 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2740 ev |= POLLIN; 2741 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2742 ev |= POLLOUT; 2743 /* Pack a pfd entry if any event armed for this fd */ 2744 if (ev != 0) { 2745 c->pfds[3] = p; 2746 pfd[p].fd = c->sock; 2747 pfd[p].events = 0; 2748 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2749 p++; 2750 } 2751 } 2752 *next_pollfd = p; 2753 } 2754 2755 /* * Allocate/prepare poll structure */ 2756 void 2757 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2758 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2759 { 2760 struct ssh_channels *sc = ssh->chanctxt; 2761 u_int i, oalloc, p, npfd = npfd_reserved; 2762 2763 channel_before_prepare_io(ssh); /* might create a new channel */ 2764 /* clear out I/O flags from last poll */ 2765 for (i = 0; i < sc->channels_alloc; i++) { 2766 if (sc->channels[i] == NULL) 2767 continue; 2768 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2769 } 2770 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2771 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2772 fatal_f("too many channels"); /* shouldn't happen */ 2773 npfd += sc->channels_alloc * 4; 2774 if (npfd > *npfd_allocp) { 2775 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2776 npfd, sizeof(**pfdp)); 2777 *npfd_allocp = npfd; 2778 } 2779 *npfd_activep = npfd_reserved; 2780 oalloc = sc->channels_alloc; 2781 2782 channel_handler(ssh, CHAN_PRE, timeout); 2783 2784 if (oalloc != sc->channels_alloc) { 2785 /* shouldn't happen */ 2786 fatal_f("channels_alloc changed during CHAN_PRE " 2787 "(was %u, now %u)", oalloc, sc->channels_alloc); 2788 } 2789 2790 /* Prepare pollfd */ 2791 p = npfd_reserved; 2792 for (i = 0; i < sc->channels_alloc; i++) 2793 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2794 *npfd_activep = p; 2795 } 2796 2797 static void 2798 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2799 const char *what, u_int revents_mask, u_int ready) 2800 { 2801 struct pollfd *pfd = &pfds[p]; 2802 2803 if (fd == -1) 2804 return; 2805 if (p == -1 || (u_int)p >= npfd) 2806 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2807 dump_channel_poll(__func__, what, c, p, pfd); 2808 if (pfd->fd != fd) { 2809 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2810 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2811 c->rfd, c->wfd, c->efd, c->sock); 2812 } 2813 if ((pfd->revents & POLLNVAL) != 0) { 2814 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2815 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2816 } 2817 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2818 c->io_ready |= ready & c->io_want; 2819 } 2820 2821 /* 2822 * After poll, perform any appropriate operations for channels which have 2823 * events pending. 2824 */ 2825 void 2826 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2827 { 2828 struct ssh_channels *sc = ssh->chanctxt; 2829 u_int i; 2830 int p; 2831 Channel *c; 2832 2833 #ifdef DEBUG_CHANNEL_POLL 2834 for (p = 0; p < (int)npfd; p++) { 2835 if (pfd[p].revents == 0) 2836 continue; 2837 debug_f("pfd[%u].fd %d rev 0x%04x", 2838 p, pfd[p].fd, pfd[p].revents); 2839 } 2840 #endif 2841 2842 /* Convert pollfd into c->io_ready */ 2843 for (i = 0; i < sc->channels_alloc; i++) { 2844 c = sc->channels[i]; 2845 if (c == NULL) 2846 continue; 2847 /* if rfd is shared with efd/sock then wfd should be too */ 2848 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2849 (c->rfd == c->efd || c->rfd == c->sock)) { 2850 /* Shouldn't happen */ 2851 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2852 c->self, c->rfd, c->wfd, c->efd, c->sock); 2853 } 2854 c->io_ready = 0; 2855 /* rfd, potentially shared with wfd, efd and sock */ 2856 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2857 fd_ready(c, p, pfd, npfd, c->rfd, 2858 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2859 if (c->rfd == c->wfd) { 2860 fd_ready(c, p, pfd, npfd, c->wfd, 2861 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2862 } 2863 if (c->rfd == c->efd) { 2864 fd_ready(c, p, pfd, npfd, c->efd, 2865 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2866 fd_ready(c, p, pfd, npfd, c->efd, 2867 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2868 } 2869 if (c->rfd == c->sock) { 2870 fd_ready(c, p, pfd, npfd, c->sock, 2871 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2872 fd_ready(c, p, pfd, npfd, c->sock, 2873 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2874 } 2875 dump_channel_poll(__func__, "rfd", c, p, pfd); 2876 } 2877 /* wfd */ 2878 if (c->wfd != -1 && c->wfd != c->rfd && 2879 (p = c->pfds[1]) != -1) { 2880 fd_ready(c, p, pfd, npfd, c->wfd, 2881 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2882 dump_channel_poll(__func__, "wfd", c, p, pfd); 2883 } 2884 /* efd */ 2885 if (c->efd != -1 && c->efd != c->rfd && 2886 (p = c->pfds[2]) != -1) { 2887 fd_ready(c, p, pfd, npfd, c->efd, 2888 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2889 fd_ready(c, p, pfd, npfd, c->efd, 2890 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2891 dump_channel_poll(__func__, "efd", c, p, pfd); 2892 } 2893 /* sock */ 2894 if (c->sock != -1 && c->sock != c->rfd && 2895 (p = c->pfds[3]) != -1) { 2896 fd_ready(c, p, pfd, npfd, c->sock, 2897 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2898 fd_ready(c, p, pfd, npfd, c->sock, 2899 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2900 dump_channel_poll(__func__, "sock", c, p, pfd); 2901 } 2902 } 2903 channel_handler(ssh, CHAN_POST, NULL); 2904 } 2905 2906 /* 2907 * Enqueue data for channels with open or draining c->input. 2908 * Returns non-zero if a packet was enqueued. 2909 */ 2910 static int 2911 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2912 { 2913 size_t len, plen; 2914 const u_char *pkt; 2915 int r; 2916 2917 if ((len = sshbuf_len(c->input)) == 0) { 2918 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2919 /* 2920 * input-buffer is empty and read-socket shutdown: 2921 * tell peer, that we will not send more data: 2922 * send IEOF. 2923 * hack for extended data: delay EOF if EFD still 2924 * in use. 2925 */ 2926 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2927 debug2("channel %d: " 2928 "ibuf_empty delayed efd %d/(%zu)", 2929 c->self, c->efd, sshbuf_len(c->extended)); 2930 else 2931 chan_ibuf_empty(ssh, c); 2932 } 2933 return 0; 2934 } 2935 2936 if (!c->have_remote_id) 2937 fatal_f("channel %d: no remote id", c->self); 2938 2939 if (c->datagram) { 2940 /* Check datagram will fit; drop if not */ 2941 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2942 fatal_fr(r, "channel %i: get datagram", c->self); 2943 /* 2944 * XXX this does tail-drop on the datagram queue which is 2945 * usually suboptimal compared to head-drop. Better to have 2946 * backpressure at read time? (i.e. read + discard) 2947 */ 2948 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2949 debug("channel %d: datagram too big", c->self); 2950 return 0; 2951 } 2952 /* Enqueue it */ 2953 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2954 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2955 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2956 (r = sshpkt_send(ssh)) != 0) 2957 fatal_fr(r, "channel %i: send datagram", c->self); 2958 c->remote_window -= plen; 2959 return 1; 2960 } 2961 2962 /* Enqueue packet for buffered data. */ 2963 if (len > c->remote_window) 2964 len = c->remote_window; 2965 if (len > c->remote_maxpacket) 2966 len = c->remote_maxpacket; 2967 if (len == 0) 2968 return 0; 2969 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2970 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2971 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2972 (r = sshpkt_send(ssh)) != 0) 2973 fatal_fr(r, "channel %i: send data", c->self); 2974 if ((r = sshbuf_consume(c->input, len)) != 0) 2975 fatal_fr(r, "channel %i: consume", c->self); 2976 c->remote_window -= len; 2977 return 1; 2978 } 2979 2980 /* 2981 * Enqueue data for channels with open c->extended in read mode. 2982 * Returns non-zero if a packet was enqueued. 2983 */ 2984 static int 2985 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2986 { 2987 size_t len; 2988 int r; 2989 2990 if ((len = sshbuf_len(c->extended)) == 0) 2991 return 0; 2992 2993 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2994 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2995 if (len > c->remote_window) 2996 len = c->remote_window; 2997 if (len > c->remote_maxpacket) 2998 len = c->remote_maxpacket; 2999 if (len == 0) 3000 return 0; 3001 if (!c->have_remote_id) 3002 fatal_f("channel %d: no remote id", c->self); 3003 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 3004 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3005 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 3006 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 3007 (r = sshpkt_send(ssh)) != 0) 3008 fatal_fr(r, "channel %i: data", c->self); 3009 if ((r = sshbuf_consume(c->extended, len)) != 0) 3010 fatal_fr(r, "channel %i: consume", c->self); 3011 c->remote_window -= len; 3012 debug2("channel %d: sent ext data %zu", c->self, len); 3013 return 1; 3014 } 3015 3016 /* 3017 * If there is data to send to the connection, enqueue some of it now. 3018 * Returns non-zero if data was enqueued. 3019 */ 3020 int 3021 channel_output_poll(struct ssh *ssh) 3022 { 3023 struct ssh_channels *sc = ssh->chanctxt; 3024 Channel *c; 3025 u_int i; 3026 int ret = 0; 3027 3028 for (i = 0; i < sc->channels_alloc; i++) { 3029 c = sc->channels[i]; 3030 if (c == NULL) 3031 continue; 3032 3033 /* 3034 * We are only interested in channels that can have buffered 3035 * incoming data. 3036 */ 3037 if (c->type != SSH_CHANNEL_OPEN) 3038 continue; 3039 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3040 /* XXX is this true? */ 3041 debug3("channel %d: will not send data after close", 3042 c->self); 3043 continue; 3044 } 3045 3046 /* Get the amount of buffered data for this channel. */ 3047 if (c->istate == CHAN_INPUT_OPEN || 3048 c->istate == CHAN_INPUT_WAIT_DRAIN) 3049 ret |= channel_output_poll_input_open(ssh, c); 3050 /* Send extended data, i.e. stderr */ 3051 if (!(c->flags & CHAN_EOF_SENT) && 3052 c->extended_usage == CHAN_EXTENDED_READ) 3053 ret |= channel_output_poll_extended_read(ssh, c); 3054 } 3055 return ret; 3056 } 3057 3058 /* -- mux proxy support */ 3059 3060 /* 3061 * When multiplexing channel messages for mux clients we have to deal 3062 * with downstream messages from the mux client and upstream messages 3063 * from the ssh server: 3064 * 1) Handling downstream messages is straightforward and happens 3065 * in channel_proxy_downstream(): 3066 * - We forward all messages (mostly) unmodified to the server. 3067 * - However, in order to route messages from upstream to the correct 3068 * downstream client, we have to replace the channel IDs used by the 3069 * mux clients with a unique channel ID because the mux clients might 3070 * use conflicting channel IDs. 3071 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3072 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3073 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3074 * with the newly allocated channel ID. 3075 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3076 * channels and processed by channel_proxy_upstream(). The local channel ID 3077 * is then translated back to the original mux client ID. 3078 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3079 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3080 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3081 * downstream mux client are removed. 3082 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3083 * requires more work, because they are not addressed to a specific 3084 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3085 * out whether the request is addressed to the local client or a 3086 * specific downstream client based on the listen-address/port. 3087 * 6) Agent and X11-Forwarding have a similar problem and are currently 3088 * not supported as the matching session/channel cannot be identified 3089 * easily. 3090 */ 3091 3092 /* 3093 * receive packets from downstream mux clients: 3094 * channel callback fired on read from mux client, creates 3095 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3096 * on channel creation. 3097 */ 3098 int 3099 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3100 { 3101 Channel *c = NULL; 3102 struct sshbuf *original = NULL, *modified = NULL; 3103 const u_char *cp; 3104 char *ctype = NULL, *listen_host = NULL; 3105 u_char type; 3106 size_t have; 3107 int ret = -1, r; 3108 u_int id, remote_id, listen_port; 3109 3110 /* sshbuf_dump(downstream->input, stderr); */ 3111 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3112 != 0) { 3113 error_fr(r, "parse"); 3114 return -1; 3115 } 3116 if (have < 2) { 3117 error_f("short message"); 3118 return -1; 3119 } 3120 type = cp[1]; 3121 /* skip padlen + type */ 3122 cp += 2; 3123 have -= 2; 3124 if (ssh_packet_log_type(type)) 3125 debug3_f("channel %u: down->up: type %u", 3126 downstream->self, type); 3127 3128 switch (type) { 3129 case SSH2_MSG_CHANNEL_OPEN: 3130 if ((original = sshbuf_from(cp, have)) == NULL || 3131 (modified = sshbuf_new()) == NULL) { 3132 error_f("alloc"); 3133 goto out; 3134 } 3135 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3136 (r = sshbuf_get_u32(original, &id)) != 0) { 3137 error_fr(r, "parse"); 3138 goto out; 3139 } 3140 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3141 -1, -1, -1, 0, 0, 0, ctype, 1); 3142 c->mux_ctx = downstream; /* point to mux client */ 3143 c->mux_downstream_id = id; /* original downstream id */ 3144 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3145 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3146 (r = sshbuf_putb(modified, original)) != 0) { 3147 error_fr(r, "compose"); 3148 channel_free(ssh, c); 3149 goto out; 3150 } 3151 break; 3152 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3153 /* 3154 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3155 * need to parse 'remote_id' instead of 'ctype'. 3156 */ 3157 if ((original = sshbuf_from(cp, have)) == NULL || 3158 (modified = sshbuf_new()) == NULL) { 3159 error_f("alloc"); 3160 goto out; 3161 } 3162 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3163 (r = sshbuf_get_u32(original, &id)) != 0) { 3164 error_fr(r, "parse"); 3165 goto out; 3166 } 3167 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3168 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3169 c->mux_ctx = downstream; /* point to mux client */ 3170 c->mux_downstream_id = id; 3171 c->remote_id = remote_id; 3172 c->have_remote_id = 1; 3173 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3174 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3175 (r = sshbuf_putb(modified, original)) != 0) { 3176 error_fr(r, "compose"); 3177 channel_free(ssh, c); 3178 goto out; 3179 } 3180 break; 3181 case SSH2_MSG_GLOBAL_REQUEST: 3182 if ((original = sshbuf_from(cp, have)) == NULL) { 3183 error_f("alloc"); 3184 goto out; 3185 } 3186 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3187 error_fr(r, "parse"); 3188 goto out; 3189 } 3190 if (strcmp(ctype, "tcpip-forward") != 0) { 3191 error_f("unsupported request %s", ctype); 3192 goto out; 3193 } 3194 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3195 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3196 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3197 error_fr(r, "parse"); 3198 goto out; 3199 } 3200 if (listen_port > 65535) { 3201 error_f("tcpip-forward for %s: bad port %u", 3202 listen_host, listen_port); 3203 goto out; 3204 } 3205 /* Record that connection to this host/port is permitted. */ 3206 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 3207 listen_host, NULL, (int)listen_port, downstream); 3208 listen_host = NULL; 3209 break; 3210 case SSH2_MSG_CHANNEL_CLOSE: 3211 if (have < 4) 3212 break; 3213 remote_id = PEEK_U32(cp); 3214 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3215 if (c->flags & CHAN_CLOSE_RCVD) 3216 channel_free(ssh, c); 3217 else 3218 c->flags |= CHAN_CLOSE_SENT; 3219 } 3220 break; 3221 } 3222 if (modified) { 3223 if ((r = sshpkt_start(ssh, type)) != 0 || 3224 (r = sshpkt_putb(ssh, modified)) != 0 || 3225 (r = sshpkt_send(ssh)) != 0) { 3226 error_fr(r, "send"); 3227 goto out; 3228 } 3229 } else { 3230 if ((r = sshpkt_start(ssh, type)) != 0 || 3231 (r = sshpkt_put(ssh, cp, have)) != 0 || 3232 (r = sshpkt_send(ssh)) != 0) { 3233 error_fr(r, "send"); 3234 goto out; 3235 } 3236 } 3237 ret = 0; 3238 out: 3239 free(ctype); 3240 free(listen_host); 3241 sshbuf_free(original); 3242 sshbuf_free(modified); 3243 return ret; 3244 } 3245 3246 /* 3247 * receive packets from upstream server and de-multiplex packets 3248 * to correct downstream: 3249 * implemented as a helper for channel input handlers, 3250 * replaces local (proxy) channel ID with downstream channel ID. 3251 */ 3252 int 3253 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3254 { 3255 struct sshbuf *b = NULL; 3256 Channel *downstream; 3257 const u_char *cp = NULL; 3258 size_t len; 3259 int r; 3260 3261 /* 3262 * When receiving packets from the peer we need to check whether we 3263 * need to forward the packets to the mux client. In this case we 3264 * restore the original channel id and keep track of CLOSE messages, 3265 * so we can cleanup the channel. 3266 */ 3267 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3268 return 0; 3269 if ((downstream = c->mux_ctx) == NULL) 3270 return 0; 3271 switch (type) { 3272 case SSH2_MSG_CHANNEL_CLOSE: 3273 case SSH2_MSG_CHANNEL_DATA: 3274 case SSH2_MSG_CHANNEL_EOF: 3275 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3276 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3277 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3278 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3279 case SSH2_MSG_CHANNEL_SUCCESS: 3280 case SSH2_MSG_CHANNEL_FAILURE: 3281 case SSH2_MSG_CHANNEL_REQUEST: 3282 break; 3283 default: 3284 debug2_f("channel %u: unsupported type %u", c->self, type); 3285 return 0; 3286 } 3287 if ((b = sshbuf_new()) == NULL) { 3288 error_f("alloc reply"); 3289 goto out; 3290 } 3291 /* get remaining payload (after id) */ 3292 cp = sshpkt_ptr(ssh, &len); 3293 if (cp == NULL) { 3294 error_f("no packet"); 3295 goto out; 3296 } 3297 /* translate id and send to muxclient */ 3298 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3299 (r = sshbuf_put_u8(b, type)) != 0 || 3300 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3301 (r = sshbuf_put(b, cp, len)) != 0 || 3302 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3303 error_fr(r, "compose muxclient"); 3304 goto out; 3305 } 3306 /* sshbuf_dump(b, stderr); */ 3307 if (ssh_packet_log_type(type)) 3308 debug3_f("channel %u: up->down: type %u", c->self, type); 3309 out: 3310 /* update state */ 3311 switch (type) { 3312 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3313 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3314 if (cp && len > 4) { 3315 c->remote_id = PEEK_U32(cp); 3316 c->have_remote_id = 1; 3317 } 3318 break; 3319 case SSH2_MSG_CHANNEL_CLOSE: 3320 if (c->flags & CHAN_CLOSE_SENT) 3321 channel_free(ssh, c); 3322 else 3323 c->flags |= CHAN_CLOSE_RCVD; 3324 break; 3325 } 3326 sshbuf_free(b); 3327 return 1; 3328 } 3329 3330 /* -- protocol input */ 3331 3332 /* Parse a channel ID from the current packet */ 3333 static int 3334 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3335 { 3336 u_int32_t id; 3337 int r; 3338 3339 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3340 error_r(r, "%s: parse id", where); 3341 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3342 } 3343 if (id > INT_MAX) { 3344 error_r(r, "%s: bad channel id %u", where, id); 3345 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3346 } 3347 return (int)id; 3348 } 3349 3350 /* Lookup a channel from an ID in the current packet */ 3351 static Channel * 3352 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3353 { 3354 int id = channel_parse_id(ssh, where, what); 3355 Channel *c; 3356 3357 if ((c = channel_lookup(ssh, id)) == NULL) { 3358 ssh_packet_disconnect(ssh, 3359 "%s packet referred to nonexistent channel %d", what, id); 3360 } 3361 return c; 3362 } 3363 3364 int 3365 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3366 { 3367 const u_char *data; 3368 size_t data_len, win_len; 3369 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3370 int r; 3371 3372 if (channel_proxy_upstream(c, type, seq, ssh)) 3373 return 0; 3374 3375 /* Ignore any data for non-open channels (might happen on close) */ 3376 if (c->type != SSH_CHANNEL_OPEN && 3377 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3378 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3379 c->type != SSH_CHANNEL_X11_OPEN) 3380 return 0; 3381 3382 /* Get the data. */ 3383 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3384 (r = sshpkt_get_end(ssh)) != 0) 3385 fatal_fr(r, "channel %i: get data", c->self); 3386 3387 win_len = data_len; 3388 if (c->datagram) 3389 win_len += 4; /* string length header */ 3390 3391 /* 3392 * The sending side reduces its window as it sends data, so we 3393 * must 'fake' consumption of the data in order to ensure that window 3394 * updates are sent back. Otherwise the connection might deadlock. 3395 */ 3396 if (c->ostate != CHAN_OUTPUT_OPEN) { 3397 c->local_window -= win_len; 3398 c->local_consumed += win_len; 3399 return 0; 3400 } 3401 3402 if (win_len > c->local_maxpacket) { 3403 logit("channel %d: rcvd big packet %zu, maxpack %u", 3404 c->self, win_len, c->local_maxpacket); 3405 return 0; 3406 } 3407 if (win_len > c->local_window) { 3408 c->local_window_exceeded += win_len - c->local_window; 3409 logit("channel %d: rcvd too much data %zu, win %u/%u " 3410 "(excess %u)", c->self, win_len, c->local_window, 3411 c->local_window_max, c->local_window_exceeded); 3412 c->local_window = 0; 3413 /* Allow 10% grace before bringing the hammer down */ 3414 if (c->local_window_exceeded > (c->local_window_max / 10)) { 3415 ssh_packet_disconnect(ssh, "channel %d: peer ignored " 3416 "channel window", c->self); 3417 } 3418 } else { 3419 c->local_window -= win_len; 3420 c->local_window_exceeded = 0; 3421 } 3422 3423 if (c->datagram) { 3424 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3425 fatal_fr(r, "channel %i: append datagram", c->self); 3426 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3427 fatal_fr(r, "channel %i: append data", c->self); 3428 3429 return 0; 3430 } 3431 3432 int 3433 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3434 { 3435 const u_char *data; 3436 size_t data_len; 3437 u_int32_t tcode; 3438 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3439 int r; 3440 3441 if (channel_proxy_upstream(c, type, seq, ssh)) 3442 return 0; 3443 if (c->type != SSH_CHANNEL_OPEN) { 3444 logit("channel %d: ext data for non open", c->self); 3445 return 0; 3446 } 3447 if (c->flags & CHAN_EOF_RCVD) { 3448 if (ssh->compat & SSH_BUG_EXTEOF) 3449 debug("channel %d: accepting ext data after eof", 3450 c->self); 3451 else 3452 ssh_packet_disconnect(ssh, "Received extended_data " 3453 "after EOF on channel %d.", c->self); 3454 } 3455 3456 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3457 error_fr(r, "parse tcode"); 3458 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3459 } 3460 if (c->efd == -1 || 3461 c->extended_usage != CHAN_EXTENDED_WRITE || 3462 tcode != SSH2_EXTENDED_DATA_STDERR) { 3463 logit("channel %d: bad ext data", c->self); 3464 return 0; 3465 } 3466 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3467 (r = sshpkt_get_end(ssh)) != 0) { 3468 error_fr(r, "parse data"); 3469 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3470 } 3471 3472 if (data_len > c->local_window) { 3473 logit("channel %d: rcvd too much extended_data %zu, win %u", 3474 c->self, data_len, c->local_window); 3475 return 0; 3476 } 3477 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3478 /* XXX sshpkt_getb? */ 3479 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3480 error_fr(r, "append"); 3481 c->local_window -= data_len; 3482 return 0; 3483 } 3484 3485 int 3486 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3487 { 3488 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3489 int r; 3490 3491 if ((r = sshpkt_get_end(ssh)) != 0) { 3492 error_fr(r, "parse data"); 3493 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3494 } 3495 3496 if (channel_proxy_upstream(c, type, seq, ssh)) 3497 return 0; 3498 chan_rcvd_ieof(ssh, c); 3499 3500 /* XXX force input close */ 3501 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3502 debug("channel %d: FORCE input drain", c->self); 3503 c->istate = CHAN_INPUT_WAIT_DRAIN; 3504 if (sshbuf_len(c->input) == 0) 3505 chan_ibuf_empty(ssh, c); 3506 } 3507 return 0; 3508 } 3509 3510 int 3511 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3512 { 3513 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3514 int r; 3515 3516 if (channel_proxy_upstream(c, type, seq, ssh)) 3517 return 0; 3518 if ((r = sshpkt_get_end(ssh)) != 0) { 3519 error_fr(r, "parse data"); 3520 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3521 } 3522 chan_rcvd_oclose(ssh, c); 3523 return 0; 3524 } 3525 3526 int 3527 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3528 { 3529 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3530 u_int32_t remote_window, remote_maxpacket; 3531 int r; 3532 3533 if (channel_proxy_upstream(c, type, seq, ssh)) 3534 return 0; 3535 if (c->type != SSH_CHANNEL_OPENING) 3536 ssh_packet_disconnect(ssh, "Received open confirmation for " 3537 "non-opening channel %d.", c->self); 3538 /* 3539 * Record the remote channel number and mark that the channel 3540 * is now open. 3541 */ 3542 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3543 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3544 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3545 (r = sshpkt_get_end(ssh)) != 0) { 3546 error_fr(r, "window/maxpacket"); 3547 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3548 } 3549 3550 c->have_remote_id = 1; 3551 c->remote_window = remote_window; 3552 c->remote_maxpacket = remote_maxpacket; 3553 c->type = SSH_CHANNEL_OPEN; 3554 if (c->open_confirm) { 3555 debug2_f("channel %d: callback start", c->self); 3556 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3557 debug2_f("channel %d: callback done", c->self); 3558 } 3559 channel_set_used_time(ssh, c); 3560 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3561 c->remote_window, c->remote_maxpacket); 3562 return 0; 3563 } 3564 3565 static char * 3566 reason2txt(int reason) 3567 { 3568 switch (reason) { 3569 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3570 return "administratively prohibited"; 3571 case SSH2_OPEN_CONNECT_FAILED: 3572 return "connect failed"; 3573 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3574 return "unknown channel type"; 3575 case SSH2_OPEN_RESOURCE_SHORTAGE: 3576 return "resource shortage"; 3577 } 3578 return "unknown reason"; 3579 } 3580 3581 int 3582 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3583 { 3584 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3585 u_int32_t reason; 3586 char *msg = NULL; 3587 int r; 3588 3589 if (channel_proxy_upstream(c, type, seq, ssh)) 3590 return 0; 3591 if (c->type != SSH_CHANNEL_OPENING) 3592 ssh_packet_disconnect(ssh, "Received open failure for " 3593 "non-opening channel %d.", c->self); 3594 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3595 error_fr(r, "parse reason"); 3596 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3597 } 3598 /* skip language */ 3599 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3600 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3601 (r = sshpkt_get_end(ssh)) != 0) { 3602 error_fr(r, "parse msg/lang"); 3603 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3604 } 3605 logit("channel %d: open failed: %s%s%s", c->self, 3606 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3607 free(msg); 3608 if (c->open_confirm) { 3609 debug2_f("channel %d: callback start", c->self); 3610 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3611 debug2_f("channel %d: callback done", c->self); 3612 } 3613 /* Schedule the channel for cleanup/deletion. */ 3614 chan_mark_dead(ssh, c); 3615 return 0; 3616 } 3617 3618 int 3619 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3620 { 3621 int id = channel_parse_id(ssh, __func__, "window adjust"); 3622 Channel *c; 3623 u_int32_t adjust; 3624 u_int new_rwin; 3625 int r; 3626 3627 if ((c = channel_lookup(ssh, id)) == NULL) { 3628 logit("Received window adjust for non-open channel %d.", id); 3629 return 0; 3630 } 3631 3632 if (channel_proxy_upstream(c, type, seq, ssh)) 3633 return 0; 3634 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3635 (r = sshpkt_get_end(ssh)) != 0) { 3636 error_fr(r, "parse adjust"); 3637 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3638 } 3639 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3640 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3641 fatal("channel %d: adjust %u overflows remote window %u", 3642 c->self, adjust, c->remote_window); 3643 } 3644 c->remote_window = new_rwin; 3645 return 0; 3646 } 3647 3648 int 3649 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3650 { 3651 int id = channel_parse_id(ssh, __func__, "status confirm"); 3652 Channel *c; 3653 struct channel_confirm *cc; 3654 3655 /* Reset keepalive timeout */ 3656 ssh_packet_set_alive_timeouts(ssh, 0); 3657 3658 debug2_f("type %d id %d", type, id); 3659 3660 if ((c = channel_lookup(ssh, id)) == NULL) { 3661 logit_f("%d: unknown", id); 3662 return 0; 3663 } 3664 if (channel_proxy_upstream(c, type, seq, ssh)) 3665 return 0; 3666 if (sshpkt_get_end(ssh) != 0) 3667 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3668 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3669 return 0; 3670 cc->cb(ssh, type, c, cc->ctx); 3671 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3672 freezero(cc, sizeof(*cc)); 3673 return 0; 3674 } 3675 3676 /* -- tcp forwarding */ 3677 3678 void 3679 channel_set_af(struct ssh *ssh, int af) 3680 { 3681 ssh->chanctxt->IPv4or6 = af; 3682 } 3683 3684 3685 /* 3686 * Determine whether or not a port forward listens to loopback, the 3687 * specified address or wildcard. On the client, a specified bind 3688 * address will always override gateway_ports. On the server, a 3689 * gateway_ports of 1 (``yes'') will override the client's specification 3690 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3691 * will bind to whatever address the client asked for. 3692 * 3693 * Special-case listen_addrs are: 3694 * 3695 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3696 * "" (empty string), "*" -> wildcard v4/v6 3697 * "localhost" -> loopback v4/v6 3698 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3699 */ 3700 static const char * 3701 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3702 int is_client, struct ForwardOptions *fwd_opts) 3703 { 3704 const char *addr = NULL; 3705 int wildcard = 0; 3706 3707 if (listen_addr == NULL) { 3708 /* No address specified: default to gateway_ports setting */ 3709 if (fwd_opts->gateway_ports) 3710 wildcard = 1; 3711 } else if (fwd_opts->gateway_ports || is_client) { 3712 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3713 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3714 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3715 (!is_client && fwd_opts->gateway_ports == 1)) { 3716 wildcard = 1; 3717 /* 3718 * Notify client if they requested a specific listen 3719 * address and it was overridden. 3720 */ 3721 if (*listen_addr != '\0' && 3722 strcmp(listen_addr, "0.0.0.0") != 0 && 3723 strcmp(listen_addr, "*") != 0) { 3724 ssh_packet_send_debug(ssh, 3725 "Forwarding listen address " 3726 "\"%s\" overridden by server " 3727 "GatewayPorts", listen_addr); 3728 } 3729 } else if (strcmp(listen_addr, "localhost") != 0 || 3730 strcmp(listen_addr, "127.0.0.1") == 0 || 3731 strcmp(listen_addr, "::1") == 0) { 3732 /* 3733 * Accept explicit localhost address when 3734 * GatewayPorts=yes. The "localhost" hostname is 3735 * deliberately skipped here so it will listen on all 3736 * available local address families. 3737 */ 3738 addr = listen_addr; 3739 } 3740 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3741 strcmp(listen_addr, "::1") == 0) { 3742 /* 3743 * If a specific IPv4/IPv6 localhost address has been 3744 * requested then accept it even if gateway_ports is in 3745 * effect. This allows the client to prefer IPv4 or IPv6. 3746 */ 3747 addr = listen_addr; 3748 } 3749 if (wildcardp != NULL) 3750 *wildcardp = wildcard; 3751 return addr; 3752 } 3753 3754 static int 3755 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3756 struct Forward *fwd, int *allocated_listen_port, 3757 struct ForwardOptions *fwd_opts) 3758 { 3759 Channel *c; 3760 int sock, r, success = 0, wildcard = 0, is_client; 3761 struct addrinfo hints, *ai, *aitop; 3762 const char *host, *addr; 3763 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3764 in_port_t *lport_p; 3765 3766 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3767 3768 if (is_client && fwd->connect_path != NULL) { 3769 host = fwd->connect_path; 3770 } else { 3771 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3772 fwd->listen_host : fwd->connect_host; 3773 if (host == NULL) { 3774 error("No forward host name."); 3775 return 0; 3776 } 3777 if (strlen(host) >= NI_MAXHOST) { 3778 error("Forward host name too long."); 3779 return 0; 3780 } 3781 } 3782 3783 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3784 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3785 is_client, fwd_opts); 3786 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3787 (addr == NULL) ? "NULL" : addr); 3788 3789 /* 3790 * getaddrinfo returns a loopback address if the hostname is 3791 * set to NULL and hints.ai_flags is not AI_PASSIVE 3792 */ 3793 memset(&hints, 0, sizeof(hints)); 3794 hints.ai_family = ssh->chanctxt->IPv4or6; 3795 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3796 hints.ai_socktype = SOCK_STREAM; 3797 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3798 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3799 if (addr == NULL) { 3800 /* This really shouldn't happen */ 3801 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3802 ssh_gai_strerror(r)); 3803 } else { 3804 error_f("getaddrinfo(%.64s): %s", addr, 3805 ssh_gai_strerror(r)); 3806 } 3807 return 0; 3808 } 3809 if (allocated_listen_port != NULL) 3810 *allocated_listen_port = 0; 3811 for (ai = aitop; ai; ai = ai->ai_next) { 3812 switch (ai->ai_family) { 3813 case AF_INET: 3814 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3815 sin_port; 3816 break; 3817 case AF_INET6: 3818 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3819 sin6_port; 3820 break; 3821 default: 3822 continue; 3823 } 3824 /* 3825 * If allocating a port for -R forwards, then use the 3826 * same port for all address families. 3827 */ 3828 if (type == SSH_CHANNEL_RPORT_LISTENER && 3829 fwd->listen_port == 0 && allocated_listen_port != NULL && 3830 *allocated_listen_port > 0) 3831 *lport_p = htons(*allocated_listen_port); 3832 3833 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3834 strport, sizeof(strport), 3835 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3836 error_f("getnameinfo failed"); 3837 continue; 3838 } 3839 /* Create a port to listen for the host. */ 3840 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3841 if (sock == -1) { 3842 /* this is no error since kernel may not support ipv6 */ 3843 verbose("socket [%s]:%s: %.100s", ntop, strport, 3844 strerror(errno)); 3845 continue; 3846 } 3847 3848 set_reuseaddr(sock); 3849 3850 debug("Local forwarding listening on %s port %s.", 3851 ntop, strport); 3852 3853 /* Bind the socket to the address. */ 3854 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3855 /* 3856 * address can be in if use ipv6 address is 3857 * already bound 3858 */ 3859 verbose("bind [%s]:%s: %.100s", 3860 ntop, strport, strerror(errno)); 3861 close(sock); 3862 continue; 3863 } 3864 /* Start listening for connections on the socket. */ 3865 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3866 error("listen [%s]:%s: %.100s", ntop, strport, 3867 strerror(errno)); 3868 close(sock); 3869 continue; 3870 } 3871 3872 /* 3873 * fwd->listen_port == 0 requests a dynamically allocated port - 3874 * record what we got. 3875 */ 3876 if (type == SSH_CHANNEL_RPORT_LISTENER && 3877 fwd->listen_port == 0 && 3878 allocated_listen_port != NULL && 3879 *allocated_listen_port == 0) { 3880 *allocated_listen_port = get_local_port(sock); 3881 debug("Allocated listen port %d", 3882 *allocated_listen_port); 3883 } 3884 3885 /* Allocate a channel number for the socket. */ 3886 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3887 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3888 0, "port listener", 1); 3889 c->path = xstrdup(host); 3890 c->host_port = fwd->connect_port; 3891 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3892 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3893 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3894 c->listening_port = *allocated_listen_port; 3895 else 3896 c->listening_port = fwd->listen_port; 3897 success = 1; 3898 } 3899 if (success == 0) 3900 error_f("cannot listen to port: %d", fwd->listen_port); 3901 freeaddrinfo(aitop); 3902 return success; 3903 } 3904 3905 static int 3906 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3907 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3908 { 3909 struct sockaddr_un sunaddr; 3910 const char *path; 3911 Channel *c; 3912 int port, sock; 3913 mode_t omask; 3914 3915 switch (type) { 3916 case SSH_CHANNEL_UNIX_LISTENER: 3917 if (fwd->connect_path != NULL) { 3918 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3919 error("Local connecting path too long: %s", 3920 fwd->connect_path); 3921 return 0; 3922 } 3923 path = fwd->connect_path; 3924 port = PORT_STREAMLOCAL; 3925 } else { 3926 if (fwd->connect_host == NULL) { 3927 error("No forward host name."); 3928 return 0; 3929 } 3930 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3931 error("Forward host name too long."); 3932 return 0; 3933 } 3934 path = fwd->connect_host; 3935 port = fwd->connect_port; 3936 } 3937 break; 3938 case SSH_CHANNEL_RUNIX_LISTENER: 3939 path = fwd->listen_path; 3940 port = PORT_STREAMLOCAL; 3941 break; 3942 default: 3943 error_f("unexpected channel type %d", type); 3944 return 0; 3945 } 3946 3947 if (fwd->listen_path == NULL) { 3948 error("No forward path name."); 3949 return 0; 3950 } 3951 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3952 error("Local listening path too long: %s", fwd->listen_path); 3953 return 0; 3954 } 3955 3956 debug3_f("type %d path %s", type, fwd->listen_path); 3957 3958 /* Start a Unix domain listener. */ 3959 omask = umask(fwd_opts->streamlocal_bind_mask); 3960 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3961 fwd_opts->streamlocal_bind_unlink); 3962 umask(omask); 3963 if (sock < 0) 3964 return 0; 3965 3966 debug("Local forwarding listening on path %s.", fwd->listen_path); 3967 3968 /* Allocate a channel number for the socket. */ 3969 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 3970 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3971 0, "unix listener", 1); 3972 c->path = xstrdup(path); 3973 c->host_port = port; 3974 c->listening_port = PORT_STREAMLOCAL; 3975 c->listening_addr = xstrdup(fwd->listen_path); 3976 return 1; 3977 } 3978 3979 static int 3980 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3981 const char *host, u_short port) 3982 { 3983 u_int i; 3984 int found = 0; 3985 3986 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3987 Channel *c = ssh->chanctxt->channels[i]; 3988 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3989 continue; 3990 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3991 debug2_f("close channel %d", i); 3992 channel_free(ssh, c); 3993 found = 1; 3994 } 3995 } 3996 3997 return found; 3998 } 3999 4000 static int 4001 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 4002 { 4003 u_int i; 4004 int found = 0; 4005 4006 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4007 Channel *c = ssh->chanctxt->channels[i]; 4008 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 4009 continue; 4010 if (c->path == NULL) 4011 continue; 4012 if (strcmp(c->path, path) == 0) { 4013 debug2_f("close channel %d", i); 4014 channel_free(ssh, c); 4015 found = 1; 4016 } 4017 } 4018 4019 return found; 4020 } 4021 4022 int 4023 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4024 { 4025 if (fwd->listen_path != NULL) { 4026 return channel_cancel_rport_listener_streamlocal(ssh, 4027 fwd->listen_path); 4028 } else { 4029 return channel_cancel_rport_listener_tcpip(ssh, 4030 fwd->listen_host, fwd->listen_port); 4031 } 4032 } 4033 4034 static int 4035 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4036 const char *lhost, u_short lport, int cport, 4037 struct ForwardOptions *fwd_opts) 4038 { 4039 u_int i; 4040 int found = 0; 4041 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4042 4043 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4044 Channel *c = ssh->chanctxt->channels[i]; 4045 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4046 continue; 4047 if (c->listening_port != lport) 4048 continue; 4049 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4050 /* skip dynamic forwardings */ 4051 if (c->host_port == 0) 4052 continue; 4053 } else { 4054 if (c->host_port != cport) 4055 continue; 4056 } 4057 if ((c->listening_addr == NULL && addr != NULL) || 4058 (c->listening_addr != NULL && addr == NULL)) 4059 continue; 4060 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4061 debug2_f("close channel %d", i); 4062 channel_free(ssh, c); 4063 found = 1; 4064 } 4065 } 4066 4067 return found; 4068 } 4069 4070 static int 4071 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4072 { 4073 u_int i; 4074 int found = 0; 4075 4076 if (path == NULL) { 4077 error_f("no path specified."); 4078 return 0; 4079 } 4080 4081 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4082 Channel *c = ssh->chanctxt->channels[i]; 4083 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4084 continue; 4085 if (c->listening_addr == NULL) 4086 continue; 4087 if (strcmp(c->listening_addr, path) == 0) { 4088 debug2_f("close channel %d", i); 4089 channel_free(ssh, c); 4090 found = 1; 4091 } 4092 } 4093 4094 return found; 4095 } 4096 4097 int 4098 channel_cancel_lport_listener(struct ssh *ssh, 4099 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4100 { 4101 if (fwd->listen_path != NULL) { 4102 return channel_cancel_lport_listener_streamlocal(ssh, 4103 fwd->listen_path); 4104 } else { 4105 return channel_cancel_lport_listener_tcpip(ssh, 4106 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4107 } 4108 } 4109 4110 /* protocol local port fwd, used by ssh */ 4111 int 4112 channel_setup_local_fwd_listener(struct ssh *ssh, 4113 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4114 { 4115 if (fwd->listen_path != NULL) { 4116 return channel_setup_fwd_listener_streamlocal(ssh, 4117 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4118 } else { 4119 return channel_setup_fwd_listener_tcpip(ssh, 4120 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4121 } 4122 } 4123 4124 /* Matches a remote forwarding permission against a requested forwarding */ 4125 static int 4126 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4127 { 4128 int ret; 4129 char *lhost; 4130 4131 /* XXX add ACLs for streamlocal */ 4132 if (fwd->listen_path != NULL) 4133 return 1; 4134 4135 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4136 return 0; 4137 4138 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4139 allowed_open->listen_port != fwd->listen_port) 4140 return 0; 4141 4142 /* Match hostnames case-insensitively */ 4143 lhost = xstrdup(fwd->listen_host); 4144 lowercase(lhost); 4145 ret = match_pattern(lhost, allowed_open->listen_host); 4146 free(lhost); 4147 4148 return ret; 4149 } 4150 4151 /* Checks whether a requested remote forwarding is permitted */ 4152 static int 4153 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4154 { 4155 struct ssh_channels *sc = ssh->chanctxt; 4156 struct permission_set *pset = &sc->remote_perms; 4157 u_int i, permit, permit_adm = 1; 4158 struct permission *perm; 4159 4160 /* XXX apply GatewayPorts override before checking? */ 4161 4162 permit = pset->all_permitted; 4163 if (!permit) { 4164 for (i = 0; i < pset->num_permitted_user; i++) { 4165 perm = &pset->permitted_user[i]; 4166 if (remote_open_match(perm, fwd)) { 4167 permit = 1; 4168 break; 4169 } 4170 } 4171 } 4172 4173 if (pset->num_permitted_admin > 0) { 4174 permit_adm = 0; 4175 for (i = 0; i < pset->num_permitted_admin; i++) { 4176 perm = &pset->permitted_admin[i]; 4177 if (remote_open_match(perm, fwd)) { 4178 permit_adm = 1; 4179 break; 4180 } 4181 } 4182 } 4183 4184 return permit && permit_adm; 4185 } 4186 4187 /* protocol v2 remote port fwd, used by sshd */ 4188 int 4189 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4190 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4191 { 4192 if (!check_rfwd_permission(ssh, fwd)) { 4193 ssh_packet_send_debug(ssh, "port forwarding refused"); 4194 if (fwd->listen_path != NULL) 4195 /* XXX always allowed, see remote_open_match() */ 4196 logit("Received request from %.100s port %d to " 4197 "remote forward to path \"%.100s\", " 4198 "but the request was denied.", 4199 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4200 fwd->listen_path); 4201 else if(fwd->listen_host != NULL) 4202 logit("Received request from %.100s port %d to " 4203 "remote forward to host %.100s port %d, " 4204 "but the request was denied.", 4205 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4206 fwd->listen_host, fwd->listen_port ); 4207 else 4208 logit("Received request from %.100s port %d to remote " 4209 "forward, but the request was denied.", 4210 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4211 return 0; 4212 } 4213 if (fwd->listen_path != NULL) { 4214 return channel_setup_fwd_listener_streamlocal(ssh, 4215 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4216 } else { 4217 return channel_setup_fwd_listener_tcpip(ssh, 4218 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4219 fwd_opts); 4220 } 4221 } 4222 4223 /* 4224 * Translate the requested rfwd listen host to something usable for 4225 * this server. 4226 */ 4227 static const char * 4228 channel_rfwd_bind_host(const char *listen_host) 4229 { 4230 if (listen_host == NULL) { 4231 return "localhost"; 4232 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4233 return ""; 4234 } else 4235 return listen_host; 4236 } 4237 4238 /* 4239 * Initiate forwarding of connections to port "port" on remote host through 4240 * the secure channel to host:port from local side. 4241 * Returns handle (index) for updating the dynamic listen port with 4242 * channel_update_permission(). 4243 */ 4244 int 4245 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4246 { 4247 int r, success = 0, idx = -1; 4248 const char *host_to_connect, *listen_host, *listen_path; 4249 int port_to_connect, listen_port; 4250 4251 /* Send the forward request to the remote side. */ 4252 if (fwd->listen_path != NULL) { 4253 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4254 (r = sshpkt_put_cstring(ssh, 4255 "streamlocal-forward@openssh.com")) != 0 || 4256 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4257 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4258 (r = sshpkt_send(ssh)) != 0 || 4259 (r = ssh_packet_write_wait(ssh)) != 0) 4260 fatal_fr(r, "request streamlocal"); 4261 } else { 4262 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4263 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4264 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4265 (r = sshpkt_put_cstring(ssh, 4266 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4267 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4268 (r = sshpkt_send(ssh)) != 0 || 4269 (r = ssh_packet_write_wait(ssh)) != 0) 4270 fatal_fr(r, "request tcpip-forward"); 4271 } 4272 /* Assume that server accepts the request */ 4273 success = 1; 4274 if (success) { 4275 /* Record that connection to this host/port is permitted. */ 4276 host_to_connect = listen_host = listen_path = NULL; 4277 port_to_connect = listen_port = 0; 4278 if (fwd->connect_path != NULL) { 4279 host_to_connect = fwd->connect_path; 4280 port_to_connect = PORT_STREAMLOCAL; 4281 } else { 4282 host_to_connect = fwd->connect_host; 4283 port_to_connect = fwd->connect_port; 4284 } 4285 if (fwd->listen_path != NULL) { 4286 listen_path = fwd->listen_path; 4287 listen_port = PORT_STREAMLOCAL; 4288 } else { 4289 listen_host = fwd->listen_host; 4290 listen_port = fwd->listen_port; 4291 } 4292 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4293 host_to_connect, port_to_connect, 4294 listen_host, listen_path, listen_port, NULL); 4295 } 4296 return idx; 4297 } 4298 4299 static int 4300 open_match(struct permission *allowed_open, const char *requestedhost, 4301 int requestedport) 4302 { 4303 if (allowed_open->host_to_connect == NULL) 4304 return 0; 4305 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4306 allowed_open->port_to_connect != requestedport) 4307 return 0; 4308 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4309 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4310 return 0; 4311 return 1; 4312 } 4313 4314 /* 4315 * Note that in the listen host/port case 4316 * we don't support FWD_PERMIT_ANY_PORT and 4317 * need to translate between the configured-host (listen_host) 4318 * and what we've sent to the remote server (channel_rfwd_bind_host) 4319 */ 4320 static int 4321 open_listen_match_tcpip(struct permission *allowed_open, 4322 const char *requestedhost, u_short requestedport, int translate) 4323 { 4324 const char *allowed_host; 4325 4326 if (allowed_open->host_to_connect == NULL) 4327 return 0; 4328 if (allowed_open->listen_port != requestedport) 4329 return 0; 4330 if (!translate && allowed_open->listen_host == NULL && 4331 requestedhost == NULL) 4332 return 1; 4333 allowed_host = translate ? 4334 channel_rfwd_bind_host(allowed_open->listen_host) : 4335 allowed_open->listen_host; 4336 if (allowed_host == NULL || requestedhost == NULL || 4337 strcmp(allowed_host, requestedhost) != 0) 4338 return 0; 4339 return 1; 4340 } 4341 4342 static int 4343 open_listen_match_streamlocal(struct permission *allowed_open, 4344 const char *requestedpath) 4345 { 4346 if (allowed_open->host_to_connect == NULL) 4347 return 0; 4348 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4349 return 0; 4350 if (allowed_open->listen_path == NULL || 4351 strcmp(allowed_open->listen_path, requestedpath) != 0) 4352 return 0; 4353 return 1; 4354 } 4355 4356 /* 4357 * Request cancellation of remote forwarding of connection host:port from 4358 * local side. 4359 */ 4360 static int 4361 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4362 const char *host, u_short port) 4363 { 4364 struct ssh_channels *sc = ssh->chanctxt; 4365 struct permission_set *pset = &sc->local_perms; 4366 int r; 4367 u_int i; 4368 struct permission *perm = NULL; 4369 4370 for (i = 0; i < pset->num_permitted_user; i++) { 4371 perm = &pset->permitted_user[i]; 4372 if (open_listen_match_tcpip(perm, host, port, 0)) 4373 break; 4374 perm = NULL; 4375 } 4376 if (perm == NULL) { 4377 debug_f("requested forward not found"); 4378 return -1; 4379 } 4380 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4381 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4382 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4383 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4384 (r = sshpkt_put_u32(ssh, port)) != 0 || 4385 (r = sshpkt_send(ssh)) != 0) 4386 fatal_fr(r, "send cancel"); 4387 4388 fwd_perm_clear(perm); /* unregister */ 4389 4390 return 0; 4391 } 4392 4393 /* 4394 * Request cancellation of remote forwarding of Unix domain socket 4395 * path from local side. 4396 */ 4397 static int 4398 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4399 { 4400 struct ssh_channels *sc = ssh->chanctxt; 4401 struct permission_set *pset = &sc->local_perms; 4402 int r; 4403 u_int i; 4404 struct permission *perm = NULL; 4405 4406 for (i = 0; i < pset->num_permitted_user; i++) { 4407 perm = &pset->permitted_user[i]; 4408 if (open_listen_match_streamlocal(perm, path)) 4409 break; 4410 perm = NULL; 4411 } 4412 if (perm == NULL) { 4413 debug_f("requested forward not found"); 4414 return -1; 4415 } 4416 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4417 (r = sshpkt_put_cstring(ssh, 4418 "cancel-streamlocal-forward@openssh.com")) != 0 || 4419 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4420 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4421 (r = sshpkt_send(ssh)) != 0) 4422 fatal_fr(r, "send cancel"); 4423 4424 fwd_perm_clear(perm); /* unregister */ 4425 4426 return 0; 4427 } 4428 4429 /* 4430 * Request cancellation of remote forwarding of a connection from local side. 4431 */ 4432 int 4433 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4434 { 4435 if (fwd->listen_path != NULL) { 4436 return channel_request_rforward_cancel_streamlocal(ssh, 4437 fwd->listen_path); 4438 } else { 4439 return channel_request_rforward_cancel_tcpip(ssh, 4440 fwd->listen_host, 4441 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4442 } 4443 } 4444 4445 /* 4446 * Permits opening to any host/port if permitted_user[] is empty. This is 4447 * usually called by the server, because the user could connect to any port 4448 * anyway, and the server has no way to know but to trust the client anyway. 4449 */ 4450 void 4451 channel_permit_all(struct ssh *ssh, int where) 4452 { 4453 struct permission_set *pset = permission_set_get(ssh, where); 4454 4455 if (pset->num_permitted_user == 0) 4456 pset->all_permitted = 1; 4457 } 4458 4459 /* 4460 * Permit the specified host/port for forwarding. 4461 */ 4462 void 4463 channel_add_permission(struct ssh *ssh, int who, int where, 4464 char *host, int port) 4465 { 4466 int local = where == FORWARD_LOCAL; 4467 struct permission_set *pset = permission_set_get(ssh, where); 4468 4469 debug("allow %s forwarding to host %s port %d", 4470 fwd_ident(who, where), host, port); 4471 /* 4472 * Remote forwards set listen_host/port, local forwards set 4473 * host/port_to_connect. 4474 */ 4475 permission_set_add(ssh, who, where, 4476 local ? host : 0, local ? port : 0, 4477 local ? NULL : host, NULL, local ? 0 : port, NULL); 4478 pset->all_permitted = 0; 4479 } 4480 4481 /* 4482 * Administratively disable forwarding. 4483 */ 4484 void 4485 channel_disable_admin(struct ssh *ssh, int where) 4486 { 4487 channel_clear_permission(ssh, FORWARD_ADM, where); 4488 permission_set_add(ssh, FORWARD_ADM, where, 4489 NULL, 0, NULL, NULL, 0, NULL); 4490 } 4491 4492 /* 4493 * Clear a list of permitted opens. 4494 */ 4495 void 4496 channel_clear_permission(struct ssh *ssh, int who, int where) 4497 { 4498 struct permission **permp; 4499 u_int *npermp; 4500 4501 permission_set_get_array(ssh, who, where, &permp, &npermp); 4502 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4503 *npermp = 0; 4504 } 4505 4506 /* 4507 * Update the listen port for a dynamic remote forward, after 4508 * the actual 'newport' has been allocated. If 'newport' < 0 is 4509 * passed then they entry will be invalidated. 4510 */ 4511 void 4512 channel_update_permission(struct ssh *ssh, int idx, int newport) 4513 { 4514 struct permission_set *pset = &ssh->chanctxt->local_perms; 4515 4516 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4517 debug_f("index out of range: %d num_permitted_user %d", 4518 idx, pset->num_permitted_user); 4519 return; 4520 } 4521 debug("%s allowed port %d for forwarding to host %s port %d", 4522 newport > 0 ? "Updating" : "Removing", 4523 newport, 4524 pset->permitted_user[idx].host_to_connect, 4525 pset->permitted_user[idx].port_to_connect); 4526 if (newport <= 0) 4527 fwd_perm_clear(&pset->permitted_user[idx]); 4528 else { 4529 pset->permitted_user[idx].listen_port = 4530 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4531 } 4532 } 4533 4534 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4535 int 4536 permitopen_port(const char *p) 4537 { 4538 int port; 4539 4540 if (strcmp(p, "*") == 0) 4541 return FWD_PERMIT_ANY_PORT; 4542 if ((port = a2port(p)) > 0) 4543 return port; 4544 return -1; 4545 } 4546 4547 /* Try to start non-blocking connect to next host in cctx list */ 4548 static int 4549 connect_next(struct channel_connect *cctx) 4550 { 4551 int sock, saved_errno; 4552 struct sockaddr_un *sunaddr; 4553 char ntop[NI_MAXHOST]; 4554 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4555 4556 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4557 switch (cctx->ai->ai_family) { 4558 case AF_UNIX: 4559 /* unix:pathname instead of host:port */ 4560 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4561 strlcpy(ntop, "unix", sizeof(ntop)); 4562 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4563 break; 4564 case AF_INET: 4565 case AF_INET6: 4566 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4567 ntop, sizeof(ntop), strport, sizeof(strport), 4568 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4569 error_f("getnameinfo failed"); 4570 continue; 4571 } 4572 break; 4573 default: 4574 continue; 4575 } 4576 debug_f("start for host %.100s ([%.100s]:%s)", 4577 cctx->host, ntop, strport); 4578 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4579 cctx->ai->ai_protocol)) == -1) { 4580 if (cctx->ai->ai_next == NULL) 4581 error("socket: %.100s", strerror(errno)); 4582 else 4583 verbose("socket: %.100s", strerror(errno)); 4584 continue; 4585 } 4586 if (set_nonblock(sock) == -1) 4587 fatal_f("set_nonblock(%d)", sock); 4588 if (connect(sock, cctx->ai->ai_addr, 4589 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4590 debug_f("host %.100s ([%.100s]:%s): %.100s", 4591 cctx->host, ntop, strport, strerror(errno)); 4592 saved_errno = errno; 4593 close(sock); 4594 errno = saved_errno; 4595 continue; /* fail -- try next */ 4596 } 4597 if (cctx->ai->ai_family != AF_UNIX) 4598 set_nodelay(sock); 4599 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4600 cctx->host, ntop, strport, sock); 4601 cctx->ai = cctx->ai->ai_next; 4602 return sock; 4603 } 4604 return -1; 4605 } 4606 4607 static void 4608 channel_connect_ctx_free(struct channel_connect *cctx) 4609 { 4610 free(cctx->host); 4611 if (cctx->aitop) { 4612 if (cctx->aitop->ai_family == AF_UNIX) 4613 free(cctx->aitop); 4614 else 4615 freeaddrinfo(cctx->aitop); 4616 } 4617 memset(cctx, 0, sizeof(*cctx)); 4618 } 4619 4620 /* 4621 * Return connecting socket to remote host:port or local socket path, 4622 * passing back the failure reason if appropriate. 4623 */ 4624 static int 4625 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4626 char *ctype, char *rname, struct channel_connect *cctx, 4627 int *reason, const char **errmsg) 4628 { 4629 struct addrinfo hints; 4630 int gaierr; 4631 int sock = -1; 4632 char strport[NI_MAXSERV]; 4633 4634 if (port == PORT_STREAMLOCAL) { 4635 struct sockaddr_un *sunaddr; 4636 struct addrinfo *ai; 4637 4638 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4639 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4640 return -1; 4641 } 4642 4643 /* 4644 * Fake up a struct addrinfo for AF_UNIX connections. 4645 * channel_connect_ctx_free() must check ai_family 4646 * and use free() not freeaddirinfo() for AF_UNIX. 4647 */ 4648 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4649 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4650 ai->ai_addr = (struct sockaddr *)(ai + 1); 4651 ai->ai_addrlen = sizeof(*sunaddr); 4652 ai->ai_family = AF_UNIX; 4653 ai->ai_socktype = socktype; 4654 ai->ai_protocol = PF_UNSPEC; 4655 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4656 sunaddr->sun_family = AF_UNIX; 4657 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4658 cctx->aitop = ai; 4659 } else { 4660 memset(&hints, 0, sizeof(hints)); 4661 hints.ai_family = ssh->chanctxt->IPv4or6; 4662 hints.ai_socktype = socktype; 4663 snprintf(strport, sizeof strport, "%d", port); 4664 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4665 != 0) { 4666 if (errmsg != NULL) 4667 *errmsg = ssh_gai_strerror(gaierr); 4668 if (reason != NULL) 4669 *reason = SSH2_OPEN_CONNECT_FAILED; 4670 error("connect_to %.100s: unknown host (%s)", name, 4671 ssh_gai_strerror(gaierr)); 4672 return -1; 4673 } 4674 } 4675 4676 cctx->host = xstrdup(name); 4677 cctx->port = port; 4678 cctx->ai = cctx->aitop; 4679 4680 if ((sock = connect_next(cctx)) == -1) { 4681 error("connect to %.100s port %d failed: %s", 4682 name, port, strerror(errno)); 4683 return -1; 4684 } 4685 4686 return sock; 4687 } 4688 4689 /* Return CONNECTING channel to remote host:port or local socket path */ 4690 static Channel * 4691 connect_to(struct ssh *ssh, const char *host, int port, 4692 char *ctype, char *rname) 4693 { 4694 struct channel_connect cctx; 4695 Channel *c; 4696 int sock; 4697 4698 memset(&cctx, 0, sizeof(cctx)); 4699 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4700 &cctx, NULL, NULL); 4701 if (sock == -1) { 4702 channel_connect_ctx_free(&cctx); 4703 return NULL; 4704 } 4705 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4706 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4707 c->host_port = port; 4708 c->path = xstrdup(host); 4709 c->connect_ctx = cctx; 4710 4711 return c; 4712 } 4713 4714 /* 4715 * returns either the newly connected channel or the downstream channel 4716 * that needs to deal with this connection. 4717 */ 4718 Channel * 4719 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4720 u_short listen_port, char *ctype, char *rname) 4721 { 4722 struct ssh_channels *sc = ssh->chanctxt; 4723 struct permission_set *pset = &sc->local_perms; 4724 u_int i; 4725 struct permission *perm; 4726 4727 for (i = 0; i < pset->num_permitted_user; i++) { 4728 perm = &pset->permitted_user[i]; 4729 if (open_listen_match_tcpip(perm, 4730 listen_host, listen_port, 1)) { 4731 if (perm->downstream) 4732 return perm->downstream; 4733 if (perm->port_to_connect == 0) 4734 return rdynamic_connect_prepare(ssh, 4735 ctype, rname); 4736 return connect_to(ssh, 4737 perm->host_to_connect, perm->port_to_connect, 4738 ctype, rname); 4739 } 4740 } 4741 error("WARNING: Server requests forwarding for unknown listen_port %d", 4742 listen_port); 4743 return NULL; 4744 } 4745 4746 Channel * 4747 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4748 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_streamlocal(perm, path)) { 4758 return connect_to(ssh, 4759 perm->host_to_connect, perm->port_to_connect, 4760 ctype, rname); 4761 } 4762 } 4763 error("WARNING: Server requests forwarding for unknown path %.100s", 4764 path); 4765 return NULL; 4766 } 4767 4768 /* Check if connecting to that port is permitted and connect. */ 4769 Channel * 4770 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4771 char *ctype, char *rname, int *reason, const char **errmsg) 4772 { 4773 struct ssh_channels *sc = ssh->chanctxt; 4774 struct permission_set *pset = &sc->local_perms; 4775 struct channel_connect cctx; 4776 Channel *c; 4777 u_int i, permit, permit_adm = 1; 4778 int sock; 4779 struct permission *perm; 4780 4781 permit = pset->all_permitted; 4782 if (!permit) { 4783 for (i = 0; i < pset->num_permitted_user; i++) { 4784 perm = &pset->permitted_user[i]; 4785 if (open_match(perm, host, port)) { 4786 permit = 1; 4787 break; 4788 } 4789 } 4790 } 4791 4792 if (pset->num_permitted_admin > 0) { 4793 permit_adm = 0; 4794 for (i = 0; i < pset->num_permitted_admin; i++) { 4795 perm = &pset->permitted_admin[i]; 4796 if (open_match(perm, host, port)) { 4797 permit_adm = 1; 4798 break; 4799 } 4800 } 4801 } 4802 4803 if (!permit || !permit_adm) { 4804 logit("Received request from %.100s port %d to connect to " 4805 "host %.100s port %d, but the request was denied.", 4806 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4807 if (reason != NULL) 4808 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4809 return NULL; 4810 } 4811 4812 memset(&cctx, 0, sizeof(cctx)); 4813 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4814 &cctx, reason, errmsg); 4815 if (sock == -1) { 4816 channel_connect_ctx_free(&cctx); 4817 return NULL; 4818 } 4819 4820 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4821 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4822 c->host_port = port; 4823 c->path = xstrdup(host); 4824 c->connect_ctx = cctx; 4825 4826 return c; 4827 } 4828 4829 /* Check if connecting to that path is permitted and connect. */ 4830 Channel * 4831 channel_connect_to_path(struct ssh *ssh, const char *path, 4832 char *ctype, char *rname) 4833 { 4834 struct ssh_channels *sc = ssh->chanctxt; 4835 struct permission_set *pset = &sc->local_perms; 4836 u_int i, permit, permit_adm = 1; 4837 struct permission *perm; 4838 4839 permit = pset->all_permitted; 4840 if (!permit) { 4841 for (i = 0; i < pset->num_permitted_user; i++) { 4842 perm = &pset->permitted_user[i]; 4843 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4844 permit = 1; 4845 break; 4846 } 4847 } 4848 } 4849 4850 if (pset->num_permitted_admin > 0) { 4851 permit_adm = 0; 4852 for (i = 0; i < pset->num_permitted_admin; i++) { 4853 perm = &pset->permitted_admin[i]; 4854 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4855 permit_adm = 1; 4856 break; 4857 } 4858 } 4859 } 4860 4861 if (!permit || !permit_adm) { 4862 logit("Received request to connect to path %.100s, " 4863 "but the request was denied.", path); 4864 return NULL; 4865 } 4866 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4867 } 4868 4869 void 4870 channel_send_window_changes(struct ssh *ssh) 4871 { 4872 struct ssh_channels *sc = ssh->chanctxt; 4873 struct winsize ws; 4874 int r; 4875 u_int i; 4876 4877 for (i = 0; i < sc->channels_alloc; i++) { 4878 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4879 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4880 continue; 4881 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4882 continue; 4883 channel_request_start(ssh, i, "window-change", 0); 4884 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4885 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4886 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4887 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4888 (r = sshpkt_send(ssh)) != 0) 4889 fatal_fr(r, "channel %u; send window-change", i); 4890 } 4891 } 4892 4893 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4894 static Channel * 4895 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4896 { 4897 Channel *c; 4898 int r; 4899 4900 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4901 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4902 c->host_port = 0; 4903 c->path = NULL; 4904 4905 /* 4906 * We need to open the channel before we have a FD, 4907 * so that we can get SOCKS header from peer. 4908 */ 4909 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4910 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4911 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4912 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4913 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4914 fatal_fr(r, "channel %i; confirm", c->self); 4915 return c; 4916 } 4917 4918 /* Return CONNECTING socket to remote host:port or local socket path */ 4919 static int 4920 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4921 { 4922 struct ssh_channels *sc = ssh->chanctxt; 4923 struct permission_set *pset = &sc->local_perms; 4924 struct permission *perm; 4925 struct channel_connect cctx; 4926 u_int i, permit_adm = 1; 4927 int sock; 4928 4929 if (pset->num_permitted_admin > 0) { 4930 permit_adm = 0; 4931 for (i = 0; i < pset->num_permitted_admin; i++) { 4932 perm = &pset->permitted_admin[i]; 4933 if (open_match(perm, c->path, c->host_port)) { 4934 permit_adm = 1; 4935 break; 4936 } 4937 } 4938 } 4939 if (!permit_adm) { 4940 debug_f("requested forward not permitted"); 4941 return -1; 4942 } 4943 4944 memset(&cctx, 0, sizeof(cctx)); 4945 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4946 NULL, &cctx, NULL, NULL); 4947 if (sock == -1) 4948 channel_connect_ctx_free(&cctx); 4949 else { 4950 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4951 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4952 c->connect_ctx = cctx; 4953 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4954 } 4955 return sock; 4956 } 4957 4958 /* -- X11 forwarding */ 4959 4960 /* 4961 * Creates an internet domain socket for listening for X11 connections. 4962 * Returns 0 and a suitable display number for the DISPLAY variable 4963 * stored in display_numberp , or -1 if an error occurs. 4964 */ 4965 int 4966 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4967 int x11_use_localhost, int single_connection, 4968 u_int *display_numberp, int **chanids) 4969 { 4970 Channel *nc = NULL; 4971 int display_number, sock; 4972 u_short port; 4973 struct addrinfo hints, *ai, *aitop; 4974 char strport[NI_MAXSERV]; 4975 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4976 4977 if (chanids == NULL) 4978 return -1; 4979 4980 for (display_number = x11_display_offset; 4981 display_number < MAX_DISPLAYS; 4982 display_number++) { 4983 port = 6000 + display_number; 4984 memset(&hints, 0, sizeof(hints)); 4985 hints.ai_family = ssh->chanctxt->IPv4or6; 4986 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4987 hints.ai_socktype = SOCK_STREAM; 4988 snprintf(strport, sizeof strport, "%d", port); 4989 if ((gaierr = getaddrinfo(NULL, strport, 4990 &hints, &aitop)) != 0) { 4991 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4992 return -1; 4993 } 4994 for (ai = aitop; ai; ai = ai->ai_next) { 4995 if (ai->ai_family != AF_INET && 4996 ai->ai_family != AF_INET6) 4997 continue; 4998 sock = socket(ai->ai_family, ai->ai_socktype, 4999 ai->ai_protocol); 5000 if (sock == -1) { 5001 error("socket: %.100s", strerror(errno)); 5002 freeaddrinfo(aitop); 5003 return -1; 5004 } 5005 set_reuseaddr(sock); 5006 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5007 debug2_f("bind port %d: %.100s", port, 5008 strerror(errno)); 5009 close(sock); 5010 for (n = 0; n < num_socks; n++) 5011 close(socks[n]); 5012 num_socks = 0; 5013 break; 5014 } 5015 socks[num_socks++] = sock; 5016 if (num_socks == NUM_SOCKS) 5017 break; 5018 } 5019 freeaddrinfo(aitop); 5020 if (num_socks > 0) 5021 break; 5022 } 5023 if (display_number >= MAX_DISPLAYS) { 5024 error("Failed to allocate internet-domain X11 display socket."); 5025 return -1; 5026 } 5027 /* Start listening for connections on the socket. */ 5028 for (n = 0; n < num_socks; n++) { 5029 sock = socks[n]; 5030 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5031 error("listen: %.100s", strerror(errno)); 5032 close(sock); 5033 return -1; 5034 } 5035 } 5036 5037 /* Allocate a channel for each socket. */ 5038 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5039 for (n = 0; n < num_socks; n++) { 5040 sock = socks[n]; 5041 nc = channel_new(ssh, "x11-listener", 5042 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5043 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5044 0, "X11 inet listener", 1); 5045 nc->single_connection = single_connection; 5046 (*chanids)[n] = nc->self; 5047 } 5048 (*chanids)[n] = -1; 5049 5050 /* Return the display number for the DISPLAY environment variable. */ 5051 *display_numberp = display_number; 5052 return 0; 5053 } 5054 5055 static int 5056 connect_local_xsocket(u_int dnr) 5057 { 5058 int sock; 5059 struct sockaddr_un addr; 5060 5061 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5062 if (sock == -1) 5063 error("socket: %.100s", strerror(errno)); 5064 memset(&addr, 0, sizeof(addr)); 5065 addr.sun_family = AF_UNIX; 5066 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 5067 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5068 return sock; 5069 close(sock); 5070 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5071 return -1; 5072 } 5073 5074 int 5075 x11_connect_display(struct ssh *ssh) 5076 { 5077 u_int display_number; 5078 const char *display; 5079 char buf[1024], *cp; 5080 struct addrinfo hints, *ai, *aitop; 5081 char strport[NI_MAXSERV]; 5082 int gaierr, sock = 0; 5083 5084 /* Try to open a socket for the local X server. */ 5085 display = getenv("DISPLAY"); 5086 if (!display) { 5087 error("DISPLAY not set."); 5088 return -1; 5089 } 5090 /* 5091 * Now we decode the value of the DISPLAY variable and make a 5092 * connection to the real X server. 5093 */ 5094 5095 /* 5096 * Check if it is a unix domain socket. Unix domain displays are in 5097 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5098 */ 5099 if (strncmp(display, "unix:", 5) == 0 || 5100 display[0] == ':') { 5101 /* Connect to the unix domain socket. */ 5102 if (sscanf(strrchr(display, ':') + 1, "%u", 5103 &display_number) != 1) { 5104 error("Could not parse display number from DISPLAY: " 5105 "%.100s", display); 5106 return -1; 5107 } 5108 /* Create a socket. */ 5109 sock = connect_local_xsocket(display_number); 5110 if (sock < 0) 5111 return -1; 5112 5113 /* OK, we now have a connection to the display. */ 5114 return sock; 5115 } 5116 /* 5117 * Connect to an inet socket. The DISPLAY value is supposedly 5118 * hostname:d[.s], where hostname may also be numeric IP address. 5119 */ 5120 strlcpy(buf, display, sizeof(buf)); 5121 cp = strchr(buf, ':'); 5122 if (!cp) { 5123 error("Could not find ':' in DISPLAY: %.100s", display); 5124 return -1; 5125 } 5126 *cp = 0; 5127 /* 5128 * buf now contains the host name. But first we parse the 5129 * display number. 5130 */ 5131 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5132 error("Could not parse display number from DISPLAY: %.100s", 5133 display); 5134 return -1; 5135 } 5136 5137 /* Look up the host address */ 5138 memset(&hints, 0, sizeof(hints)); 5139 hints.ai_family = ssh->chanctxt->IPv4or6; 5140 hints.ai_socktype = SOCK_STREAM; 5141 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5142 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5143 error("%.100s: unknown host. (%s)", buf, 5144 ssh_gai_strerror(gaierr)); 5145 return -1; 5146 } 5147 for (ai = aitop; ai; ai = ai->ai_next) { 5148 /* Create a socket. */ 5149 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5150 if (sock == -1) { 5151 debug2("socket: %.100s", strerror(errno)); 5152 continue; 5153 } 5154 /* Connect it to the display. */ 5155 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5156 debug2("connect %.100s port %u: %.100s", buf, 5157 6000 + display_number, strerror(errno)); 5158 close(sock); 5159 continue; 5160 } 5161 /* Success */ 5162 break; 5163 } 5164 freeaddrinfo(aitop); 5165 if (!ai) { 5166 error("connect %.100s port %u: %.100s", buf, 5167 6000 + display_number, strerror(errno)); 5168 return -1; 5169 } 5170 set_nodelay(sock); 5171 return sock; 5172 } 5173 5174 /* 5175 * Requests forwarding of X11 connections, generates fake authentication 5176 * data, and enables authentication spoofing. 5177 * This should be called in the client only. 5178 */ 5179 void 5180 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5181 const char *disp, const char *proto, const char *data, int want_reply) 5182 { 5183 struct ssh_channels *sc = ssh->chanctxt; 5184 u_int data_len = (u_int) strlen(data) / 2; 5185 u_int i, value; 5186 const char *cp; 5187 char *new_data; 5188 int r, screen_number; 5189 5190 if (sc->x11_saved_display == NULL) 5191 sc->x11_saved_display = xstrdup(disp); 5192 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5193 error("x11_request_forwarding_with_spoofing: different " 5194 "$DISPLAY already forwarded"); 5195 return; 5196 } 5197 5198 cp = strchr(disp, ':'); 5199 if (cp) 5200 cp = strchr(cp, '.'); 5201 if (cp) 5202 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5203 else 5204 screen_number = 0; 5205 5206 if (sc->x11_saved_proto == NULL) { 5207 /* Save protocol name. */ 5208 sc->x11_saved_proto = xstrdup(proto); 5209 5210 /* Extract real authentication data. */ 5211 sc->x11_saved_data = xmalloc(data_len); 5212 for (i = 0; i < data_len; i++) { 5213 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5214 fatal("x11_request_forwarding: bad " 5215 "authentication data: %.100s", data); 5216 } 5217 sc->x11_saved_data[i] = value; 5218 } 5219 sc->x11_saved_data_len = data_len; 5220 5221 /* Generate fake data of the same length. */ 5222 sc->x11_fake_data = xmalloc(data_len); 5223 arc4random_buf(sc->x11_fake_data, data_len); 5224 sc->x11_fake_data_len = data_len; 5225 } 5226 5227 /* Convert the fake data into hex. */ 5228 new_data = tohex(sc->x11_fake_data, data_len); 5229 5230 /* Send the request packet. */ 5231 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5232 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5233 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5234 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5235 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5236 (r = sshpkt_send(ssh)) != 0 || 5237 (r = ssh_packet_write_wait(ssh)) != 0) 5238 fatal_fr(r, "send x11-req"); 5239 free(new_data); 5240 } 5241