1 /* $OpenBSD: channels.c,v 1.427 2023/01/18 02:00:10 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include "includes.h" 43 44 #include <sys/types.h> 45 #include <sys/stat.h> 46 #include <sys/ioctl.h> 47 #include <sys/un.h> 48 #include <sys/socket.h> 49 #ifdef HAVE_SYS_TIME_H 50 # include <sys/time.h> 51 #endif 52 53 #include <netinet/in.h> 54 #include <arpa/inet.h> 55 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <limits.h> 59 #include <netdb.h> 60 #ifdef HAVE_POLL_H 61 #include <poll.h> 62 #endif 63 #include <stdarg.h> 64 #ifdef HAVE_STDINT_H 65 # include <stdint.h> 66 #endif 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <string.h> 70 #include <termios.h> 71 #include <unistd.h> 72 73 #include "openbsd-compat/sys-queue.h" 74 #include "xmalloc.h" 75 #include "ssh.h" 76 #include "ssh2.h" 77 #include "ssherr.h" 78 #include "sshbuf.h" 79 #include "packet.h" 80 #include "log.h" 81 #include "misc.h" 82 #include "channels.h" 83 #include "compat.h" 84 #include "canohost.h" 85 #include "sshkey.h" 86 #include "authfd.h" 87 #include "pathnames.h" 88 #include "match.h" 89 90 /* XXX remove once we're satisfied there's no lurking bugs */ 91 /* #define DEBUG_CHANNEL_POLL 1 */ 92 93 /* -- agent forwarding */ 94 #define NUM_SOCKS 10 95 96 /* -- tcp forwarding */ 97 /* special-case port number meaning allow any port */ 98 #define FWD_PERMIT_ANY_PORT 0 99 100 /* special-case wildcard meaning allow any host */ 101 #define FWD_PERMIT_ANY_HOST "*" 102 103 /* -- X11 forwarding */ 104 /* Maximum number of fake X11 displays to try. */ 105 #define MAX_DISPLAYS 1000 106 107 /* Per-channel callback for pre/post IO actions */ 108 typedef void chan_fn(struct ssh *, Channel *c); 109 110 /* 111 * Data structure for storing which hosts are permitted for forward requests. 112 * The local sides of any remote forwards are stored in this array to prevent 113 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 114 * network (which might be behind a firewall). 115 */ 116 /* XXX: streamlocal wants a path instead of host:port */ 117 /* Overload host_to_connect; we could just make this match Forward */ 118 /* XXX - can we use listen_host instead of listen_path? */ 119 struct permission { 120 char *host_to_connect; /* Connect to 'host'. */ 121 int port_to_connect; /* Connect to 'port'. */ 122 char *listen_host; /* Remote side should listen address. */ 123 char *listen_path; /* Remote side should listen path. */ 124 int listen_port; /* Remote side should listen port. */ 125 Channel *downstream; /* Downstream mux*/ 126 }; 127 128 /* 129 * Stores the forwarding permission state for a single direction (local or 130 * remote). 131 */ 132 struct permission_set { 133 /* 134 * List of all local permitted host/port pairs to allow for the 135 * user. 136 */ 137 u_int num_permitted_user; 138 struct permission *permitted_user; 139 140 /* 141 * List of all permitted host/port pairs to allow for the admin. 142 */ 143 u_int num_permitted_admin; 144 struct permission *permitted_admin; 145 146 /* 147 * If this is true, all opens/listens are permitted. This is the 148 * case on the server on which we have to trust the client anyway, 149 * and the user could do anything after logging in. 150 */ 151 int all_permitted; 152 }; 153 154 /* Used to record timeouts per channel type */ 155 struct ssh_channel_timeout { 156 char *type_pattern; 157 u_int timeout_secs; 158 }; 159 160 /* Master structure for channels state */ 161 struct ssh_channels { 162 /* 163 * Pointer to an array containing all allocated channels. The array 164 * is dynamically extended as needed. 165 */ 166 Channel **channels; 167 168 /* 169 * Size of the channel array. All slots of the array must always be 170 * initialized (at least the type field); unused slots set to NULL 171 */ 172 u_int channels_alloc; 173 174 /* 175 * 'channel_pre*' are called just before IO to add any bits 176 * relevant to channels in the c->io_want bitmasks. 177 * 178 * 'channel_post*': perform any appropriate operations for 179 * channels which have c->io_ready events pending. 180 */ 181 chan_fn **channel_pre; 182 chan_fn **channel_post; 183 184 /* -- tcp forwarding */ 185 struct permission_set local_perms; 186 struct permission_set remote_perms; 187 188 /* -- X11 forwarding */ 189 190 /* Saved X11 local (client) display. */ 191 char *x11_saved_display; 192 193 /* Saved X11 authentication protocol name. */ 194 char *x11_saved_proto; 195 196 /* Saved X11 authentication data. This is the real data. */ 197 char *x11_saved_data; 198 u_int x11_saved_data_len; 199 200 /* Deadline after which all X11 connections are refused */ 201 u_int x11_refuse_time; 202 203 /* 204 * Fake X11 authentication data. This is what the server will be 205 * sending us; we should replace any occurrences of this by the 206 * real data. 207 */ 208 u_char *x11_fake_data; 209 u_int x11_fake_data_len; 210 211 /* AF_UNSPEC or AF_INET or AF_INET6 */ 212 int IPv4or6; 213 214 /* Channel timeouts by type */ 215 struct ssh_channel_timeout *timeouts; 216 size_t ntimeouts; 217 }; 218 219 /* helper */ 220 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 221 static const char *channel_rfwd_bind_host(const char *listen_host); 222 223 /* non-blocking connect helpers */ 224 static int connect_next(struct channel_connect *); 225 static void channel_connect_ctx_free(struct channel_connect *); 226 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 227 static int rdynamic_connect_finish(struct ssh *, Channel *); 228 229 /* Setup helper */ 230 static void channel_handler_init(struct ssh_channels *sc); 231 232 /* -- channel core */ 233 234 void 235 channel_init_channels(struct ssh *ssh) 236 { 237 struct ssh_channels *sc; 238 239 if ((sc = calloc(1, sizeof(*sc))) == NULL) 240 fatal_f("allocation failed"); 241 sc->channels_alloc = 10; 242 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 243 sc->IPv4or6 = AF_UNSPEC; 244 channel_handler_init(sc); 245 246 ssh->chanctxt = sc; 247 } 248 249 Channel * 250 channel_by_id(struct ssh *ssh, int id) 251 { 252 Channel *c; 253 254 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 255 logit_f("%d: bad id", id); 256 return NULL; 257 } 258 c = ssh->chanctxt->channels[id]; 259 if (c == NULL) { 260 logit_f("%d: bad id: channel free", id); 261 return NULL; 262 } 263 return c; 264 } 265 266 Channel * 267 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 268 { 269 Channel *c; 270 u_int i; 271 272 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 273 c = ssh->chanctxt->channels[i]; 274 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 275 return c; 276 } 277 return NULL; 278 } 279 280 /* 281 * Returns the channel if it is allowed to receive protocol messages. 282 * Private channels, like listening sockets, may not receive messages. 283 */ 284 Channel * 285 channel_lookup(struct ssh *ssh, int id) 286 { 287 Channel *c; 288 289 if ((c = channel_by_id(ssh, id)) == NULL) 290 return NULL; 291 292 switch (c->type) { 293 case SSH_CHANNEL_X11_OPEN: 294 case SSH_CHANNEL_LARVAL: 295 case SSH_CHANNEL_CONNECTING: 296 case SSH_CHANNEL_DYNAMIC: 297 case SSH_CHANNEL_RDYNAMIC_OPEN: 298 case SSH_CHANNEL_RDYNAMIC_FINISH: 299 case SSH_CHANNEL_OPENING: 300 case SSH_CHANNEL_OPEN: 301 case SSH_CHANNEL_ABANDONED: 302 case SSH_CHANNEL_MUX_PROXY: 303 return c; 304 } 305 logit("Non-public channel %d, type %d.", id, c->type); 306 return NULL; 307 } 308 309 /* 310 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 311 * match type_pattern. 312 */ 313 void 314 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 315 u_int timeout_secs) 316 { 317 struct ssh_channels *sc = ssh->chanctxt; 318 319 debug2_f("channel type \"%s\" timeout %u 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 u_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 * Register filedescriptors for a channel, used when allocating a channel or 381 * when the channel consumer/producer is ready, e.g. shell exec'd 382 */ 383 static void 384 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 385 int extusage, int nonblock, int is_tty) 386 { 387 int val; 388 389 if (rfd != -1) 390 fcntl(rfd, F_SETFD, FD_CLOEXEC); 391 if (wfd != -1 && wfd != rfd) 392 fcntl(wfd, F_SETFD, FD_CLOEXEC); 393 if (efd != -1 && efd != rfd && efd != wfd) 394 fcntl(efd, F_SETFD, FD_CLOEXEC); 395 396 c->rfd = rfd; 397 c->wfd = wfd; 398 c->sock = (rfd == wfd) ? rfd : -1; 399 c->efd = efd; 400 c->extended_usage = extusage; 401 402 if ((c->isatty = is_tty) != 0) 403 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 404 #ifdef _AIX 405 /* XXX: Later AIX versions can't push as much data to tty */ 406 c->wfd_isatty = is_tty || isatty(c->wfd); 407 #endif 408 409 /* enable nonblocking mode */ 410 c->restore_block = 0; 411 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 412 /* 413 * Special handling for stdio file descriptors: do not set 414 * non-blocking mode if they are TTYs. Otherwise prepare to 415 * restore their blocking state on exit to avoid interfering 416 * with other programs that follow. 417 */ 418 if (rfd != -1 && !isatty(rfd) && 419 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 420 c->restore_flags[0] = val; 421 c->restore_block |= CHANNEL_RESTORE_RFD; 422 set_nonblock(rfd); 423 } 424 if (wfd != -1 && !isatty(wfd) && 425 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 426 c->restore_flags[1] = val; 427 c->restore_block |= CHANNEL_RESTORE_WFD; 428 set_nonblock(wfd); 429 } 430 if (efd != -1 && !isatty(efd) && 431 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 432 c->restore_flags[2] = val; 433 c->restore_block |= CHANNEL_RESTORE_EFD; 434 set_nonblock(efd); 435 } 436 } else if (nonblock) { 437 if (rfd != -1) 438 set_nonblock(rfd); 439 if (wfd != -1) 440 set_nonblock(wfd); 441 if (efd != -1) 442 set_nonblock(efd); 443 } 444 } 445 446 /* 447 * Allocate a new channel object and set its type and socket. 448 */ 449 Channel * 450 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 451 u_int window, u_int maxpack, int extusage, const char *remote_name, 452 int nonblock) 453 { 454 struct ssh_channels *sc = ssh->chanctxt; 455 u_int i, found = 0; 456 Channel *c; 457 int r; 458 459 /* Try to find a free slot where to put the new channel. */ 460 for (i = 0; i < sc->channels_alloc; i++) { 461 if (sc->channels[i] == NULL) { 462 /* Found a free slot. */ 463 found = i; 464 break; 465 } 466 } 467 if (i >= sc->channels_alloc) { 468 /* 469 * There are no free slots. Take last+1 slot and expand 470 * the array. 471 */ 472 found = sc->channels_alloc; 473 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 474 fatal_f("internal error: channels_alloc %d too big", 475 sc->channels_alloc); 476 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 477 sc->channels_alloc + 10, sizeof(*sc->channels)); 478 sc->channels_alloc += 10; 479 debug2("channel: expanding %d", sc->channels_alloc); 480 } 481 /* Initialize and return new channel. */ 482 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 483 if ((c->input = sshbuf_new()) == NULL || 484 (c->output = sshbuf_new()) == NULL || 485 (c->extended = sshbuf_new()) == NULL) 486 fatal_f("sshbuf_new failed"); 487 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 488 fatal_fr(r, "sshbuf_set_max_size"); 489 c->ostate = CHAN_OUTPUT_OPEN; 490 c->istate = CHAN_INPUT_OPEN; 491 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 492 c->self = found; 493 c->type = type; 494 c->ctype = ctype; 495 c->local_window = window; 496 c->local_window_max = window; 497 c->local_maxpacket = maxpack; 498 c->remote_name = xstrdup(remote_name); 499 c->ctl_chan = -1; 500 c->delayed = 1; /* prevent call to channel_post handler */ 501 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 502 TAILQ_INIT(&c->status_confirms); 503 debug("channel %d: new %s [%s] (inactive timeout: %u)", 504 found, c->ctype, remote_name, c->inactive_deadline); 505 return c; 506 } 507 508 int 509 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 510 { 511 int ret, fd = *fdp; 512 513 if (fd == -1) 514 return 0; 515 516 /* restore blocking */ 517 if (*fdp == c->rfd && 518 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 519 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 520 else if (*fdp == c->wfd && 521 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 522 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 523 else if (*fdp == c->efd && 524 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 525 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 526 527 if (*fdp == c->rfd) { 528 c->io_want &= ~SSH_CHAN_IO_RFD; 529 c->io_ready &= ~SSH_CHAN_IO_RFD; 530 c->rfd = -1; 531 c->pfds[0] = -1; 532 } 533 if (*fdp == c->wfd) { 534 c->io_want &= ~SSH_CHAN_IO_WFD; 535 c->io_ready &= ~SSH_CHAN_IO_WFD; 536 c->wfd = -1; 537 c->pfds[1] = -1; 538 } 539 if (*fdp == c->efd) { 540 c->io_want &= ~SSH_CHAN_IO_EFD; 541 c->io_ready &= ~SSH_CHAN_IO_EFD; 542 c->efd = -1; 543 c->pfds[2] = -1; 544 } 545 if (*fdp == c->sock) { 546 c->io_want &= ~SSH_CHAN_IO_SOCK; 547 c->io_ready &= ~SSH_CHAN_IO_SOCK; 548 c->sock = -1; 549 c->pfds[3] = -1; 550 } 551 552 ret = close(fd); 553 *fdp = -1; /* probably redundant */ 554 return ret; 555 } 556 557 /* Close all channel fd/socket. */ 558 static void 559 channel_close_fds(struct ssh *ssh, Channel *c) 560 { 561 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 562 563 channel_close_fd(ssh, c, &c->sock); 564 if (rfd != sock) 565 channel_close_fd(ssh, c, &c->rfd); 566 if (wfd != sock && wfd != rfd) 567 channel_close_fd(ssh, c, &c->wfd); 568 if (efd != sock && efd != rfd && efd != wfd) 569 channel_close_fd(ssh, c, &c->efd); 570 } 571 572 static void 573 fwd_perm_clear(struct permission *perm) 574 { 575 free(perm->host_to_connect); 576 free(perm->listen_host); 577 free(perm->listen_path); 578 memset(perm, 0, sizeof(*perm)); 579 } 580 581 /* Returns an printable name for the specified forwarding permission list */ 582 static const char * 583 fwd_ident(int who, int where) 584 { 585 if (who == FORWARD_ADM) { 586 if (where == FORWARD_LOCAL) 587 return "admin local"; 588 else if (where == FORWARD_REMOTE) 589 return "admin remote"; 590 } else if (who == FORWARD_USER) { 591 if (where == FORWARD_LOCAL) 592 return "user local"; 593 else if (where == FORWARD_REMOTE) 594 return "user remote"; 595 } 596 fatal("Unknown forward permission list %d/%d", who, where); 597 } 598 599 /* Returns the forwarding permission list for the specified direction */ 600 static struct permission_set * 601 permission_set_get(struct ssh *ssh, int where) 602 { 603 struct ssh_channels *sc = ssh->chanctxt; 604 605 switch (where) { 606 case FORWARD_LOCAL: 607 return &sc->local_perms; 608 break; 609 case FORWARD_REMOTE: 610 return &sc->remote_perms; 611 break; 612 default: 613 fatal_f("invalid forwarding direction %d", where); 614 } 615 } 616 617 /* Returns pointers to the specified forwarding list and its element count */ 618 static void 619 permission_set_get_array(struct ssh *ssh, int who, int where, 620 struct permission ***permpp, u_int **npermpp) 621 { 622 struct permission_set *pset = permission_set_get(ssh, where); 623 624 switch (who) { 625 case FORWARD_USER: 626 *permpp = &pset->permitted_user; 627 *npermpp = &pset->num_permitted_user; 628 break; 629 case FORWARD_ADM: 630 *permpp = &pset->permitted_admin; 631 *npermpp = &pset->num_permitted_admin; 632 break; 633 default: 634 fatal_f("invalid forwarding client %d", who); 635 } 636 } 637 638 /* Adds an entry to the specified forwarding list */ 639 static int 640 permission_set_add(struct ssh *ssh, int who, int where, 641 const char *host_to_connect, int port_to_connect, 642 const char *listen_host, const char *listen_path, int listen_port, 643 Channel *downstream) 644 { 645 struct permission **permp; 646 u_int n, *npermp; 647 648 permission_set_get_array(ssh, who, where, &permp, &npermp); 649 650 if (*npermp >= INT_MAX) 651 fatal_f("%s overflow", fwd_ident(who, where)); 652 653 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 654 n = (*npermp)++; 655 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 656 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 657 (*permp)[n].port_to_connect = port_to_connect; 658 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 659 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 660 (*permp)[n].listen_port = listen_port; 661 (*permp)[n].downstream = downstream; 662 #undef MAYBE_DUP 663 return (int)n; 664 } 665 666 static void 667 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 668 { 669 struct ssh_channels *sc = ssh->chanctxt; 670 struct permission_set *pset = &sc->local_perms; 671 struct permission *perm; 672 int r; 673 u_int i; 674 675 for (i = 0; i < pset->num_permitted_user; i++) { 676 perm = &pset->permitted_user[i]; 677 if (perm->downstream != c) 678 continue; 679 680 /* cancel on the server, since mux client is gone */ 681 debug("channel %d: cleanup remote forward for %s:%u", 682 c->self, perm->listen_host, perm->listen_port); 683 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 684 (r = sshpkt_put_cstring(ssh, 685 "cancel-tcpip-forward")) != 0 || 686 (r = sshpkt_put_u8(ssh, 0)) != 0 || 687 (r = sshpkt_put_cstring(ssh, 688 channel_rfwd_bind_host(perm->listen_host))) != 0 || 689 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 690 (r = sshpkt_send(ssh)) != 0) { 691 fatal_fr(r, "channel %i", c->self); 692 } 693 fwd_perm_clear(perm); /* unregister */ 694 } 695 } 696 697 /* Free the channel and close its fd/socket. */ 698 void 699 channel_free(struct ssh *ssh, Channel *c) 700 { 701 struct ssh_channels *sc = ssh->chanctxt; 702 char *s; 703 u_int i, n; 704 Channel *other; 705 struct channel_confirm *cc; 706 707 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 708 if ((other = sc->channels[i]) == NULL) 709 continue; 710 n++; 711 /* detach from mux client and prepare for closing */ 712 if (c->type == SSH_CHANNEL_MUX_CLIENT && 713 other->type == SSH_CHANNEL_MUX_PROXY && 714 other->mux_ctx == c) { 715 other->mux_ctx = NULL; 716 other->type = SSH_CHANNEL_OPEN; 717 other->istate = CHAN_INPUT_CLOSED; 718 other->ostate = CHAN_OUTPUT_CLOSED; 719 } 720 } 721 debug("channel %d: free: %s, nchannels %u", c->self, 722 c->remote_name ? c->remote_name : "???", n); 723 724 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 725 mux_remove_remote_forwardings(ssh, c); 726 free(c->mux_ctx); 727 c->mux_ctx = NULL; 728 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 729 free(c->mux_ctx); 730 c->mux_ctx = NULL; 731 } 732 733 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 734 s = channel_open_message(ssh); 735 debug3("channel %d: status: %s", c->self, s); 736 free(s); 737 } 738 739 channel_close_fds(ssh, c); 740 sshbuf_free(c->input); 741 sshbuf_free(c->output); 742 sshbuf_free(c->extended); 743 c->input = c->output = c->extended = NULL; 744 free(c->remote_name); 745 c->remote_name = NULL; 746 free(c->path); 747 c->path = NULL; 748 free(c->listening_addr); 749 c->listening_addr = NULL; 750 free(c->xctype); 751 c->xctype = NULL; 752 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 753 if (cc->abandon_cb != NULL) 754 cc->abandon_cb(ssh, c, cc->ctx); 755 TAILQ_REMOVE(&c->status_confirms, cc, entry); 756 freezero(cc, sizeof(*cc)); 757 } 758 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 759 c->filter_cleanup(ssh, c->self, c->filter_ctx); 760 sc->channels[c->self] = NULL; 761 freezero(c, sizeof(*c)); 762 } 763 764 void 765 channel_free_all(struct ssh *ssh) 766 { 767 u_int i; 768 struct ssh_channels *sc = ssh->chanctxt; 769 770 for (i = 0; i < sc->channels_alloc; i++) 771 if (sc->channels[i] != NULL) 772 channel_free(ssh, sc->channels[i]); 773 774 free(sc->channels); 775 sc->channels = NULL; 776 sc->channels_alloc = 0; 777 778 free(sc->x11_saved_display); 779 sc->x11_saved_display = NULL; 780 781 free(sc->x11_saved_proto); 782 sc->x11_saved_proto = NULL; 783 784 free(sc->x11_saved_data); 785 sc->x11_saved_data = NULL; 786 sc->x11_saved_data_len = 0; 787 788 free(sc->x11_fake_data); 789 sc->x11_fake_data = NULL; 790 sc->x11_fake_data_len = 0; 791 } 792 793 /* 794 * Closes the sockets/fds of all channels. This is used to close extra file 795 * descriptors after a fork. 796 */ 797 void 798 channel_close_all(struct ssh *ssh) 799 { 800 u_int i; 801 802 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 803 if (ssh->chanctxt->channels[i] != NULL) 804 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 805 } 806 807 /* 808 * Stop listening to channels. 809 */ 810 void 811 channel_stop_listening(struct ssh *ssh) 812 { 813 u_int i; 814 Channel *c; 815 816 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 817 c = ssh->chanctxt->channels[i]; 818 if (c != NULL) { 819 switch (c->type) { 820 case SSH_CHANNEL_AUTH_SOCKET: 821 case SSH_CHANNEL_PORT_LISTENER: 822 case SSH_CHANNEL_RPORT_LISTENER: 823 case SSH_CHANNEL_X11_LISTENER: 824 case SSH_CHANNEL_UNIX_LISTENER: 825 case SSH_CHANNEL_RUNIX_LISTENER: 826 channel_close_fd(ssh, c, &c->sock); 827 channel_free(ssh, c); 828 break; 829 } 830 } 831 } 832 } 833 834 /* 835 * Returns true if no channel has too much buffered data, and false if one or 836 * more channel is overfull. 837 */ 838 int 839 channel_not_very_much_buffered_data(struct ssh *ssh) 840 { 841 u_int i; 842 u_int maxsize = ssh_packet_get_maxsize(ssh); 843 Channel *c; 844 845 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 846 c = ssh->chanctxt->channels[i]; 847 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 848 continue; 849 if (sshbuf_len(c->output) > maxsize) { 850 debug2("channel %d: big output buffer %zu > %u", 851 c->self, sshbuf_len(c->output), maxsize); 852 return 0; 853 } 854 } 855 return 1; 856 } 857 858 /* Returns true if any channel is still open. */ 859 int 860 channel_still_open(struct ssh *ssh) 861 { 862 u_int i; 863 Channel *c; 864 865 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 866 c = ssh->chanctxt->channels[i]; 867 if (c == NULL) 868 continue; 869 switch (c->type) { 870 case SSH_CHANNEL_X11_LISTENER: 871 case SSH_CHANNEL_PORT_LISTENER: 872 case SSH_CHANNEL_RPORT_LISTENER: 873 case SSH_CHANNEL_MUX_LISTENER: 874 case SSH_CHANNEL_CLOSED: 875 case SSH_CHANNEL_AUTH_SOCKET: 876 case SSH_CHANNEL_DYNAMIC: 877 case SSH_CHANNEL_RDYNAMIC_OPEN: 878 case SSH_CHANNEL_CONNECTING: 879 case SSH_CHANNEL_ZOMBIE: 880 case SSH_CHANNEL_ABANDONED: 881 case SSH_CHANNEL_UNIX_LISTENER: 882 case SSH_CHANNEL_RUNIX_LISTENER: 883 continue; 884 case SSH_CHANNEL_LARVAL: 885 continue; 886 case SSH_CHANNEL_OPENING: 887 case SSH_CHANNEL_OPEN: 888 case SSH_CHANNEL_RDYNAMIC_FINISH: 889 case SSH_CHANNEL_X11_OPEN: 890 case SSH_CHANNEL_MUX_CLIENT: 891 case SSH_CHANNEL_MUX_PROXY: 892 return 1; 893 default: 894 fatal_f("bad channel type %d", c->type); 895 /* NOTREACHED */ 896 } 897 } 898 return 0; 899 } 900 901 /* Returns the id of an open channel suitable for keepaliving */ 902 int 903 channel_find_open(struct ssh *ssh) 904 { 905 u_int i; 906 Channel *c; 907 908 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 909 c = ssh->chanctxt->channels[i]; 910 if (c == NULL || !c->have_remote_id) 911 continue; 912 switch (c->type) { 913 case SSH_CHANNEL_CLOSED: 914 case SSH_CHANNEL_DYNAMIC: 915 case SSH_CHANNEL_RDYNAMIC_OPEN: 916 case SSH_CHANNEL_RDYNAMIC_FINISH: 917 case SSH_CHANNEL_X11_LISTENER: 918 case SSH_CHANNEL_PORT_LISTENER: 919 case SSH_CHANNEL_RPORT_LISTENER: 920 case SSH_CHANNEL_MUX_LISTENER: 921 case SSH_CHANNEL_MUX_CLIENT: 922 case SSH_CHANNEL_MUX_PROXY: 923 case SSH_CHANNEL_OPENING: 924 case SSH_CHANNEL_CONNECTING: 925 case SSH_CHANNEL_ZOMBIE: 926 case SSH_CHANNEL_ABANDONED: 927 case SSH_CHANNEL_UNIX_LISTENER: 928 case SSH_CHANNEL_RUNIX_LISTENER: 929 continue; 930 case SSH_CHANNEL_LARVAL: 931 case SSH_CHANNEL_AUTH_SOCKET: 932 case SSH_CHANNEL_OPEN: 933 case SSH_CHANNEL_X11_OPEN: 934 return i; 935 default: 936 fatal_f("bad channel type %d", c->type); 937 /* NOTREACHED */ 938 } 939 } 940 return -1; 941 } 942 943 /* Returns the state of the channel's extended usage flag */ 944 const char * 945 channel_format_extended_usage(const Channel *c) 946 { 947 if (c->efd == -1) 948 return "closed"; 949 950 switch (c->extended_usage) { 951 case CHAN_EXTENDED_WRITE: 952 return "write"; 953 case CHAN_EXTENDED_READ: 954 return "read"; 955 case CHAN_EXTENDED_IGNORE: 956 return "ignore"; 957 default: 958 return "UNKNOWN"; 959 } 960 } 961 962 static char * 963 channel_format_status(const Channel *c) 964 { 965 char *ret = NULL; 966 967 xasprintf(&ret, "t%d [%s] %s%u i%u/%zu o%u/%zu e[%s]/%zu " 968 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 969 c->type, c->xctype != NULL ? c->xctype : c->ctype, 970 c->have_remote_id ? "r" : "nr", c->remote_id, 971 c->istate, sshbuf_len(c->input), 972 c->ostate, sshbuf_len(c->output), 973 channel_format_extended_usage(c), sshbuf_len(c->extended), 974 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 975 c->io_want, c->io_ready); 976 return ret; 977 } 978 979 /* 980 * Returns a message describing the currently open forwarded connections, 981 * suitable for sending to the client. The message contains crlf pairs for 982 * newlines. 983 */ 984 char * 985 channel_open_message(struct ssh *ssh) 986 { 987 struct sshbuf *buf; 988 Channel *c; 989 u_int i; 990 int r; 991 char *cp, *ret; 992 993 if ((buf = sshbuf_new()) == NULL) 994 fatal_f("sshbuf_new"); 995 if ((r = sshbuf_putf(buf, 996 "The following connections are open:\r\n")) != 0) 997 fatal_fr(r, "sshbuf_putf"); 998 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 999 c = ssh->chanctxt->channels[i]; 1000 if (c == NULL) 1001 continue; 1002 switch (c->type) { 1003 case SSH_CHANNEL_X11_LISTENER: 1004 case SSH_CHANNEL_PORT_LISTENER: 1005 case SSH_CHANNEL_RPORT_LISTENER: 1006 case SSH_CHANNEL_CLOSED: 1007 case SSH_CHANNEL_AUTH_SOCKET: 1008 case SSH_CHANNEL_ZOMBIE: 1009 case SSH_CHANNEL_ABANDONED: 1010 case SSH_CHANNEL_MUX_LISTENER: 1011 case SSH_CHANNEL_UNIX_LISTENER: 1012 case SSH_CHANNEL_RUNIX_LISTENER: 1013 continue; 1014 case SSH_CHANNEL_LARVAL: 1015 case SSH_CHANNEL_OPENING: 1016 case SSH_CHANNEL_CONNECTING: 1017 case SSH_CHANNEL_DYNAMIC: 1018 case SSH_CHANNEL_RDYNAMIC_OPEN: 1019 case SSH_CHANNEL_RDYNAMIC_FINISH: 1020 case SSH_CHANNEL_OPEN: 1021 case SSH_CHANNEL_X11_OPEN: 1022 case SSH_CHANNEL_MUX_PROXY: 1023 case SSH_CHANNEL_MUX_CLIENT: 1024 cp = channel_format_status(c); 1025 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1026 c->self, c->remote_name, cp)) != 0) { 1027 free(cp); 1028 fatal_fr(r, "sshbuf_putf"); 1029 } 1030 free(cp); 1031 continue; 1032 default: 1033 fatal_f("bad channel type %d", c->type); 1034 /* NOTREACHED */ 1035 } 1036 } 1037 if ((ret = sshbuf_dup_string(buf)) == NULL) 1038 fatal_f("sshbuf_dup_string"); 1039 sshbuf_free(buf); 1040 return ret; 1041 } 1042 1043 static void 1044 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1045 { 1046 int r; 1047 1048 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1049 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1050 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1051 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1052 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1053 fatal_r(r, "%s: channel %i: open", where, c->self); 1054 } 1055 } 1056 1057 void 1058 channel_send_open(struct ssh *ssh, int id) 1059 { 1060 Channel *c = channel_lookup(ssh, id); 1061 int r; 1062 1063 if (c == NULL) { 1064 logit("channel_send_open: %d: bad id", id); 1065 return; 1066 } 1067 debug2("channel %d: send open", id); 1068 open_preamble(ssh, __func__, c, c->ctype); 1069 if ((r = sshpkt_send(ssh)) != 0) 1070 fatal_fr(r, "channel %i", c->self); 1071 } 1072 1073 void 1074 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 1075 { 1076 Channel *c = channel_lookup(ssh, id); 1077 int r; 1078 1079 if (c == NULL) { 1080 logit_f("%d: unknown channel id", id); 1081 return; 1082 } 1083 if (!c->have_remote_id) 1084 fatal_f("channel %d: no remote id", c->self); 1085 1086 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1087 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1088 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1089 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1090 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1091 fatal_fr(r, "channel %i", c->self); 1092 } 1093 } 1094 1095 void 1096 channel_register_status_confirm(struct ssh *ssh, int id, 1097 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1098 { 1099 struct channel_confirm *cc; 1100 Channel *c; 1101 1102 if ((c = channel_lookup(ssh, id)) == NULL) 1103 fatal_f("%d: bad id", id); 1104 1105 cc = xcalloc(1, sizeof(*cc)); 1106 cc->cb = cb; 1107 cc->abandon_cb = abandon_cb; 1108 cc->ctx = ctx; 1109 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1110 } 1111 1112 void 1113 channel_register_open_confirm(struct ssh *ssh, int id, 1114 channel_open_fn *fn, void *ctx) 1115 { 1116 Channel *c = channel_lookup(ssh, id); 1117 1118 if (c == NULL) { 1119 logit_f("%d: bad id", id); 1120 return; 1121 } 1122 c->open_confirm = fn; 1123 c->open_confirm_ctx = ctx; 1124 } 1125 1126 void 1127 channel_register_cleanup(struct ssh *ssh, int id, 1128 channel_callback_fn *fn, int do_close) 1129 { 1130 Channel *c = channel_by_id(ssh, id); 1131 1132 if (c == NULL) { 1133 logit_f("%d: bad id", id); 1134 return; 1135 } 1136 c->detach_user = fn; 1137 c->detach_close = do_close; 1138 } 1139 1140 void 1141 channel_cancel_cleanup(struct ssh *ssh, int id) 1142 { 1143 Channel *c = channel_by_id(ssh, id); 1144 1145 if (c == NULL) { 1146 logit_f("%d: bad id", id); 1147 return; 1148 } 1149 c->detach_user = NULL; 1150 c->detach_close = 0; 1151 } 1152 1153 void 1154 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1155 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1156 { 1157 Channel *c = channel_lookup(ssh, id); 1158 1159 if (c == NULL) { 1160 logit_f("%d: bad id", id); 1161 return; 1162 } 1163 c->input_filter = ifn; 1164 c->output_filter = ofn; 1165 c->filter_ctx = ctx; 1166 c->filter_cleanup = cfn; 1167 } 1168 1169 void 1170 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1171 int extusage, int nonblock, int is_tty, u_int window_max) 1172 { 1173 Channel *c = channel_lookup(ssh, id); 1174 int r; 1175 1176 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1177 fatal("channel_activate for non-larval channel %d.", id); 1178 if (!c->have_remote_id) 1179 fatal_f("channel %d: no remote id", c->self); 1180 1181 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1182 c->type = SSH_CHANNEL_OPEN; 1183 c->lastused = monotime(); 1184 c->local_window = c->local_window_max = window_max; 1185 1186 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1187 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1188 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1189 (r = sshpkt_send(ssh)) != 0) 1190 fatal_fr(r, "channel %i", c->self); 1191 } 1192 1193 static void 1194 channel_pre_listener(struct ssh *ssh, Channel *c) 1195 { 1196 c->io_want = SSH_CHAN_IO_SOCK_R; 1197 } 1198 1199 static void 1200 channel_pre_connecting(struct ssh *ssh, Channel *c) 1201 { 1202 debug3("channel %d: waiting for connection", c->self); 1203 c->io_want = SSH_CHAN_IO_SOCK_W; 1204 } 1205 1206 static void 1207 channel_pre_open(struct ssh *ssh, Channel *c) 1208 { 1209 c->io_want = 0; 1210 if (c->istate == CHAN_INPUT_OPEN && 1211 c->remote_window > 0 && 1212 sshbuf_len(c->input) < c->remote_window && 1213 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1214 c->io_want |= SSH_CHAN_IO_RFD; 1215 if (c->ostate == CHAN_OUTPUT_OPEN || 1216 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1217 if (sshbuf_len(c->output) > 0) { 1218 c->io_want |= SSH_CHAN_IO_WFD; 1219 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1220 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1221 debug2("channel %d: " 1222 "obuf_empty delayed efd %d/(%zu)", c->self, 1223 c->efd, sshbuf_len(c->extended)); 1224 else 1225 chan_obuf_empty(ssh, c); 1226 } 1227 } 1228 /** XXX check close conditions, too */ 1229 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1230 c->ostate == CHAN_OUTPUT_CLOSED)) { 1231 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1232 sshbuf_len(c->extended) > 0) 1233 c->io_want |= SSH_CHAN_IO_EFD_W; 1234 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1235 (c->extended_usage == CHAN_EXTENDED_READ || 1236 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1237 sshbuf_len(c->extended) < c->remote_window) 1238 c->io_want |= SSH_CHAN_IO_EFD_R; 1239 } 1240 /* XXX: What about efd? races? */ 1241 } 1242 1243 /* 1244 * This is a special state for X11 authentication spoofing. An opened X11 1245 * connection (when authentication spoofing is being done) remains in this 1246 * state until the first packet has been completely read. The authentication 1247 * data in that packet is then substituted by the real data if it matches the 1248 * fake data, and the channel is put into normal mode. 1249 * XXX All this happens at the client side. 1250 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1251 */ 1252 static int 1253 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1254 { 1255 struct ssh_channels *sc = ssh->chanctxt; 1256 u_char *ucp; 1257 u_int proto_len, data_len; 1258 1259 /* Is this being called after the refusal deadline? */ 1260 if (sc->x11_refuse_time != 0 && 1261 (u_int)monotime() >= sc->x11_refuse_time) { 1262 verbose("Rejected X11 connection after ForwardX11Timeout " 1263 "expired"); 1264 return -1; 1265 } 1266 1267 /* Check if the fixed size part of the packet is in buffer. */ 1268 if (sshbuf_len(b) < 12) 1269 return 0; 1270 1271 /* Parse the lengths of variable-length fields. */ 1272 ucp = sshbuf_mutable_ptr(b); 1273 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1274 proto_len = 256 * ucp[6] + ucp[7]; 1275 data_len = 256 * ucp[8] + ucp[9]; 1276 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1277 proto_len = ucp[6] + 256 * ucp[7]; 1278 data_len = ucp[8] + 256 * ucp[9]; 1279 } else { 1280 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1281 ucp[0]); 1282 return -1; 1283 } 1284 1285 /* Check if the whole packet is in buffer. */ 1286 if (sshbuf_len(b) < 1287 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1288 return 0; 1289 1290 /* Check if authentication protocol matches. */ 1291 if (proto_len != strlen(sc->x11_saved_proto) || 1292 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1293 debug2("X11 connection uses different authentication protocol."); 1294 return -1; 1295 } 1296 /* Check if authentication data matches our fake data. */ 1297 if (data_len != sc->x11_fake_data_len || 1298 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1299 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1300 debug2("X11 auth data does not match fake data."); 1301 return -1; 1302 } 1303 /* Check fake data length */ 1304 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1305 error("X11 fake_data_len %d != saved_data_len %d", 1306 sc->x11_fake_data_len, sc->x11_saved_data_len); 1307 return -1; 1308 } 1309 /* 1310 * Received authentication protocol and data match 1311 * our fake data. Substitute the fake data with real 1312 * data. 1313 */ 1314 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1315 sc->x11_saved_data, sc->x11_saved_data_len); 1316 return 1; 1317 } 1318 1319 void 1320 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1321 { 1322 debug3_f("channel %d: forcibly closing", c->self); 1323 if (c->istate == CHAN_INPUT_OPEN) 1324 chan_read_failed(ssh, c); 1325 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1326 sshbuf_reset(c->input); 1327 chan_ibuf_empty(ssh, c); 1328 } 1329 if (c->ostate == CHAN_OUTPUT_OPEN || 1330 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1331 sshbuf_reset(c->output); 1332 chan_write_failed(ssh, c); 1333 } 1334 if (c->detach_user) 1335 c->detach_user(ssh, c->self, 1, NULL); 1336 if (c->efd != -1) 1337 channel_close_fd(ssh, c, &c->efd); 1338 if (abandon) 1339 c->type = SSH_CHANNEL_ABANDONED; 1340 /* exempt from inactivity timeouts */ 1341 c->inactive_deadline = 0; 1342 c->lastused = 0; 1343 } 1344 1345 static void 1346 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1347 { 1348 int ret = x11_open_helper(ssh, c->output); 1349 1350 /* c->force_drain = 1; */ 1351 1352 if (ret == 1) { 1353 c->type = SSH_CHANNEL_OPEN; 1354 c->lastused = monotime(); 1355 channel_pre_open(ssh, c); 1356 } else if (ret == -1) { 1357 logit("X11 connection rejected because of wrong " 1358 "authentication."); 1359 debug2("X11 rejected %d i%d/o%d", 1360 c->self, c->istate, c->ostate); 1361 channel_force_close(ssh, c, 0); 1362 } 1363 } 1364 1365 static void 1366 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1367 { 1368 c->io_want = 0; 1369 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1370 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1371 c->io_want |= SSH_CHAN_IO_RFD; 1372 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1373 /* clear buffer immediately (discard any partial packet) */ 1374 sshbuf_reset(c->input); 1375 chan_ibuf_empty(ssh, c); 1376 /* Start output drain. XXX just kill chan? */ 1377 chan_rcvd_oclose(ssh, c); 1378 } 1379 if (c->ostate == CHAN_OUTPUT_OPEN || 1380 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1381 if (sshbuf_len(c->output) > 0) 1382 c->io_want |= SSH_CHAN_IO_WFD; 1383 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1384 chan_obuf_empty(ssh, c); 1385 } 1386 } 1387 1388 /* try to decode a socks4 header */ 1389 static int 1390 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1391 { 1392 const u_char *p; 1393 char *host; 1394 u_int len, have, i, found, need; 1395 char username[256]; 1396 struct { 1397 u_int8_t version; 1398 u_int8_t command; 1399 u_int16_t dest_port; 1400 struct in_addr dest_addr; 1401 } s4_req, s4_rsp; 1402 int r; 1403 1404 debug2("channel %d: decode socks4", c->self); 1405 1406 have = sshbuf_len(input); 1407 len = sizeof(s4_req); 1408 if (have < len) 1409 return 0; 1410 p = sshbuf_ptr(input); 1411 1412 need = 1; 1413 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1414 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1415 debug2("channel %d: socks4a request", c->self); 1416 /* ... and needs an extra string (the hostname) */ 1417 need = 2; 1418 } 1419 /* Check for terminating NUL on the string(s) */ 1420 for (found = 0, i = len; i < have; i++) { 1421 if (p[i] == '\0') { 1422 found++; 1423 if (found == need) 1424 break; 1425 } 1426 if (i > 1024) { 1427 /* the peer is probably sending garbage */ 1428 debug("channel %d: decode socks4: too long", 1429 c->self); 1430 return -1; 1431 } 1432 } 1433 if (found < need) 1434 return 0; 1435 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1436 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1437 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1438 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1439 debug_r(r, "channels %d: decode socks4", c->self); 1440 return -1; 1441 } 1442 have = sshbuf_len(input); 1443 p = sshbuf_ptr(input); 1444 if (memchr(p, '\0', have) == NULL) { 1445 error("channel %d: decode socks4: unterminated user", c->self); 1446 return -1; 1447 } 1448 len = strlen(p); 1449 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1450 len++; /* trailing '\0' */ 1451 strlcpy(username, p, sizeof(username)); 1452 if ((r = sshbuf_consume(input, len)) != 0) 1453 fatal_fr(r, "channel %d: consume", c->self); 1454 free(c->path); 1455 c->path = NULL; 1456 if (need == 1) { /* SOCKS4: one string */ 1457 host = inet_ntoa(s4_req.dest_addr); 1458 c->path = xstrdup(host); 1459 } else { /* SOCKS4A: two strings */ 1460 have = sshbuf_len(input); 1461 p = sshbuf_ptr(input); 1462 if (memchr(p, '\0', have) == NULL) { 1463 error("channel %d: decode socks4a: host not nul " 1464 "terminated", c->self); 1465 return -1; 1466 } 1467 len = strlen(p); 1468 debug2("channel %d: decode socks4a: host %s/%d", 1469 c->self, p, len); 1470 len++; /* trailing '\0' */ 1471 if (len > NI_MAXHOST) { 1472 error("channel %d: hostname \"%.100s\" too long", 1473 c->self, p); 1474 return -1; 1475 } 1476 c->path = xstrdup(p); 1477 if ((r = sshbuf_consume(input, len)) != 0) 1478 fatal_fr(r, "channel %d: consume", c->self); 1479 } 1480 c->host_port = ntohs(s4_req.dest_port); 1481 1482 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1483 c->self, c->path, c->host_port, s4_req.command); 1484 1485 if (s4_req.command != 1) { 1486 debug("channel %d: cannot handle: %s cn %d", 1487 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1488 return -1; 1489 } 1490 s4_rsp.version = 0; /* vn: 0 for reply */ 1491 s4_rsp.command = 90; /* cd: req granted */ 1492 s4_rsp.dest_port = 0; /* ignored */ 1493 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1494 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1495 fatal_fr(r, "channel %d: append reply", c->self); 1496 return 1; 1497 } 1498 1499 /* try to decode a socks5 header */ 1500 #define SSH_SOCKS5_AUTHDONE 0x1000 1501 #define SSH_SOCKS5_NOAUTH 0x00 1502 #define SSH_SOCKS5_IPV4 0x01 1503 #define SSH_SOCKS5_DOMAIN 0x03 1504 #define SSH_SOCKS5_IPV6 0x04 1505 #define SSH_SOCKS5_CONNECT 0x01 1506 #define SSH_SOCKS5_SUCCESS 0x00 1507 1508 static int 1509 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1510 { 1511 /* XXX use get/put_u8 instead of trusting struct padding */ 1512 struct { 1513 u_int8_t version; 1514 u_int8_t command; 1515 u_int8_t reserved; 1516 u_int8_t atyp; 1517 } s5_req, s5_rsp; 1518 u_int16_t dest_port; 1519 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1520 const u_char *p; 1521 u_int have, need, i, found, nmethods, addrlen, af; 1522 int r; 1523 1524 debug2("channel %d: decode socks5", c->self); 1525 p = sshbuf_ptr(input); 1526 if (p[0] != 0x05) 1527 return -1; 1528 have = sshbuf_len(input); 1529 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1530 /* format: ver | nmethods | methods */ 1531 if (have < 2) 1532 return 0; 1533 nmethods = p[1]; 1534 if (have < nmethods + 2) 1535 return 0; 1536 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1537 for (found = 0, i = 2; i < nmethods + 2; i++) { 1538 if (p[i] == SSH_SOCKS5_NOAUTH) { 1539 found = 1; 1540 break; 1541 } 1542 } 1543 if (!found) { 1544 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1545 c->self); 1546 return -1; 1547 } 1548 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1549 fatal_fr(r, "channel %d: consume", c->self); 1550 /* version, method */ 1551 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1552 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1553 fatal_fr(r, "channel %d: append reply", c->self); 1554 c->flags |= SSH_SOCKS5_AUTHDONE; 1555 debug2("channel %d: socks5 auth done", c->self); 1556 return 0; /* need more */ 1557 } 1558 debug2("channel %d: socks5 post auth", c->self); 1559 if (have < sizeof(s5_req)+1) 1560 return 0; /* need more */ 1561 memcpy(&s5_req, p, sizeof(s5_req)); 1562 if (s5_req.version != 0x05 || 1563 s5_req.command != SSH_SOCKS5_CONNECT || 1564 s5_req.reserved != 0x00) { 1565 debug2("channel %d: only socks5 connect supported", c->self); 1566 return -1; 1567 } 1568 switch (s5_req.atyp){ 1569 case SSH_SOCKS5_IPV4: 1570 addrlen = 4; 1571 af = AF_INET; 1572 break; 1573 case SSH_SOCKS5_DOMAIN: 1574 addrlen = p[sizeof(s5_req)]; 1575 af = -1; 1576 break; 1577 case SSH_SOCKS5_IPV6: 1578 addrlen = 16; 1579 af = AF_INET6; 1580 break; 1581 default: 1582 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1583 return -1; 1584 } 1585 need = sizeof(s5_req) + addrlen + 2; 1586 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1587 need++; 1588 if (have < need) 1589 return 0; 1590 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1591 fatal_fr(r, "channel %d: consume", c->self); 1592 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1593 /* host string length */ 1594 if ((r = sshbuf_consume(input, 1)) != 0) 1595 fatal_fr(r, "channel %d: consume", c->self); 1596 } 1597 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1598 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1599 debug_r(r, "channel %d: parse addr/port", c->self); 1600 return -1; 1601 } 1602 dest_addr[addrlen] = '\0'; 1603 free(c->path); 1604 c->path = NULL; 1605 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1606 if (addrlen >= NI_MAXHOST) { 1607 error("channel %d: dynamic request: socks5 hostname " 1608 "\"%.100s\" too long", c->self, dest_addr); 1609 return -1; 1610 } 1611 c->path = xstrdup(dest_addr); 1612 } else { 1613 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1614 return -1; 1615 c->path = xstrdup(ntop); 1616 } 1617 c->host_port = ntohs(dest_port); 1618 1619 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1620 c->self, c->path, c->host_port, s5_req.command); 1621 1622 s5_rsp.version = 0x05; 1623 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1624 s5_rsp.reserved = 0; /* ignored */ 1625 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1626 dest_port = 0; /* ignored */ 1627 1628 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1629 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1630 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1631 fatal_fr(r, "channel %d: append reply", c->self); 1632 return 1; 1633 } 1634 1635 Channel * 1636 channel_connect_stdio_fwd(struct ssh *ssh, 1637 const char *host_to_connect, u_short port_to_connect, 1638 int in, int out, int nonblock) 1639 { 1640 Channel *c; 1641 1642 debug_f("%s:%d", host_to_connect, port_to_connect); 1643 1644 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1645 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1646 0, "stdio-forward", nonblock); 1647 1648 c->path = xstrdup(host_to_connect); 1649 c->host_port = port_to_connect; 1650 c->listening_port = 0; 1651 c->force_drain = 1; 1652 1653 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1654 port_open_helper(ssh, c, "direct-tcpip"); 1655 1656 return c; 1657 } 1658 1659 /* dynamic port forwarding */ 1660 static void 1661 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1662 { 1663 const u_char *p; 1664 u_int have; 1665 int ret; 1666 1667 c->io_want = 0; 1668 have = sshbuf_len(c->input); 1669 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1670 /* sshbuf_dump(c->input, stderr); */ 1671 /* check if the fixed size part of the packet is in buffer. */ 1672 if (have < 3) { 1673 /* need more */ 1674 c->io_want |= SSH_CHAN_IO_RFD; 1675 return; 1676 } 1677 /* try to guess the protocol */ 1678 p = sshbuf_ptr(c->input); 1679 /* XXX sshbuf_peek_u8? */ 1680 switch (p[0]) { 1681 case 0x04: 1682 ret = channel_decode_socks4(c, c->input, c->output); 1683 break; 1684 case 0x05: 1685 ret = channel_decode_socks5(c, c->input, c->output); 1686 break; 1687 default: 1688 ret = -1; 1689 break; 1690 } 1691 if (ret < 0) { 1692 chan_mark_dead(ssh, c); 1693 } else if (ret == 0) { 1694 debug2("channel %d: pre_dynamic: need more", c->self); 1695 /* need more */ 1696 c->io_want |= SSH_CHAN_IO_RFD; 1697 if (sshbuf_len(c->output)) 1698 c->io_want |= SSH_CHAN_IO_WFD; 1699 } else { 1700 /* switch to the next state */ 1701 c->type = SSH_CHANNEL_OPENING; 1702 port_open_helper(ssh, c, "direct-tcpip"); 1703 } 1704 } 1705 1706 /* simulate read-error */ 1707 static void 1708 rdynamic_close(struct ssh *ssh, Channel *c) 1709 { 1710 c->type = SSH_CHANNEL_OPEN; 1711 channel_force_close(ssh, c, 0); 1712 } 1713 1714 /* reverse dynamic port forwarding */ 1715 static void 1716 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1717 { 1718 const u_char *p; 1719 u_int have, len; 1720 int r, ret; 1721 1722 have = sshbuf_len(c->output); 1723 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1724 /* sshbuf_dump(c->output, stderr); */ 1725 /* EOF received */ 1726 if (c->flags & CHAN_EOF_RCVD) { 1727 if ((r = sshbuf_consume(c->output, have)) != 0) 1728 fatal_fr(r, "channel %d: consume", c->self); 1729 rdynamic_close(ssh, c); 1730 return; 1731 } 1732 /* check if the fixed size part of the packet is in buffer. */ 1733 if (have < 3) 1734 return; 1735 /* try to guess the protocol */ 1736 p = sshbuf_ptr(c->output); 1737 switch (p[0]) { 1738 case 0x04: 1739 /* switch input/output for reverse forwarding */ 1740 ret = channel_decode_socks4(c, c->output, c->input); 1741 break; 1742 case 0x05: 1743 ret = channel_decode_socks5(c, c->output, c->input); 1744 break; 1745 default: 1746 ret = -1; 1747 break; 1748 } 1749 if (ret < 0) { 1750 rdynamic_close(ssh, c); 1751 } else if (ret == 0) { 1752 debug2("channel %d: pre_rdynamic: need more", c->self); 1753 /* send socks request to peer */ 1754 len = sshbuf_len(c->input); 1755 if (len > 0 && len < c->remote_window) { 1756 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1757 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1758 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1759 (r = sshpkt_send(ssh)) != 0) { 1760 fatal_fr(r, "channel %i: rdynamic", c->self); 1761 } 1762 if ((r = sshbuf_consume(c->input, len)) != 0) 1763 fatal_fr(r, "channel %d: consume", c->self); 1764 c->remote_window -= len; 1765 } 1766 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1767 /* the connect failed */ 1768 rdynamic_close(ssh, c); 1769 } 1770 } 1771 1772 /* This is our fake X11 server socket. */ 1773 static void 1774 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1775 { 1776 Channel *nc; 1777 struct sockaddr_storage addr; 1778 int r, newsock, oerrno, remote_port; 1779 socklen_t addrlen; 1780 char buf[16384], *remote_ipaddr; 1781 1782 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1783 return; 1784 1785 debug("X11 connection requested."); 1786 addrlen = sizeof(addr); 1787 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1788 if (c->single_connection) { 1789 oerrno = errno; 1790 debug2("single_connection: closing X11 listener."); 1791 channel_close_fd(ssh, c, &c->sock); 1792 chan_mark_dead(ssh, c); 1793 errno = oerrno; 1794 } 1795 if (newsock == -1) { 1796 if (errno != EINTR && errno != EWOULDBLOCK && 1797 errno != ECONNABORTED) 1798 error("accept: %.100s", strerror(errno)); 1799 if (errno == EMFILE || errno == ENFILE) 1800 c->notbefore = monotime() + 1; 1801 return; 1802 } 1803 set_nodelay(newsock); 1804 remote_ipaddr = get_peer_ipaddr(newsock); 1805 remote_port = get_peer_port(newsock); 1806 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1807 remote_ipaddr, remote_port); 1808 1809 nc = channel_new(ssh, "x11-connection", 1810 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1811 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1812 open_preamble(ssh, __func__, nc, "x11"); 1813 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1814 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1815 fatal_fr(r, "channel %i: reply", c->self); 1816 } 1817 if ((r = sshpkt_send(ssh)) != 0) 1818 fatal_fr(r, "channel %i: send", c->self); 1819 free(remote_ipaddr); 1820 } 1821 1822 static void 1823 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1824 { 1825 char *local_ipaddr = get_local_ipaddr(c->sock); 1826 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1827 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1828 int remote_port = get_peer_port(c->sock); 1829 int r; 1830 1831 if (remote_port == -1) { 1832 /* Fake addr/port to appease peers that validate it (Tectia) */ 1833 free(remote_ipaddr); 1834 remote_ipaddr = xstrdup("127.0.0.1"); 1835 remote_port = 65535; 1836 } 1837 1838 free(c->remote_name); 1839 xasprintf(&c->remote_name, 1840 "%s: listening port %d for %.100s port %d, " 1841 "connect from %.200s port %d to %.100s port %d", 1842 rtype, c->listening_port, c->path, c->host_port, 1843 remote_ipaddr, remote_port, local_ipaddr, local_port); 1844 1845 open_preamble(ssh, __func__, c, rtype); 1846 if (strcmp(rtype, "direct-tcpip") == 0) { 1847 /* target host, port */ 1848 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1849 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1850 fatal_fr(r, "channel %i: reply", c->self); 1851 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1852 /* target path */ 1853 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1854 fatal_fr(r, "channel %i: reply", c->self); 1855 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1856 /* listen path */ 1857 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1858 fatal_fr(r, "channel %i: reply", c->self); 1859 } else { 1860 /* listen address, port */ 1861 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1862 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1863 fatal_fr(r, "channel %i: reply", c->self); 1864 } 1865 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1866 /* reserved for future owner/mode info */ 1867 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1868 fatal_fr(r, "channel %i: reply", c->self); 1869 } else { 1870 /* originator host and port */ 1871 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1872 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1873 fatal_fr(r, "channel %i: reply", c->self); 1874 } 1875 if ((r = sshpkt_send(ssh)) != 0) 1876 fatal_fr(r, "channel %i: send", c->self); 1877 free(remote_ipaddr); 1878 free(local_ipaddr); 1879 } 1880 1881 void 1882 channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time) 1883 { 1884 ssh->chanctxt->x11_refuse_time = refuse_time; 1885 } 1886 1887 /* 1888 * This socket is listening for connections to a forwarded TCP/IP port. 1889 */ 1890 static void 1891 channel_post_port_listener(struct ssh *ssh, Channel *c) 1892 { 1893 Channel *nc; 1894 struct sockaddr_storage addr; 1895 int newsock, nextstate; 1896 socklen_t addrlen; 1897 char *rtype; 1898 1899 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1900 return; 1901 1902 debug("Connection to port %d forwarding to %.100s port %d requested.", 1903 c->listening_port, c->path, c->host_port); 1904 1905 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1906 nextstate = SSH_CHANNEL_OPENING; 1907 rtype = "forwarded-tcpip"; 1908 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1909 nextstate = SSH_CHANNEL_OPENING; 1910 rtype = "forwarded-streamlocal@openssh.com"; 1911 } else if (c->host_port == PORT_STREAMLOCAL) { 1912 nextstate = SSH_CHANNEL_OPENING; 1913 rtype = "direct-streamlocal@openssh.com"; 1914 } else if (c->host_port == 0) { 1915 nextstate = SSH_CHANNEL_DYNAMIC; 1916 rtype = "dynamic-tcpip"; 1917 } else { 1918 nextstate = SSH_CHANNEL_OPENING; 1919 rtype = "direct-tcpip"; 1920 } 1921 1922 addrlen = sizeof(addr); 1923 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1924 if (newsock == -1) { 1925 if (errno != EINTR && errno != EWOULDBLOCK && 1926 errno != ECONNABORTED) 1927 error("accept: %.100s", strerror(errno)); 1928 if (errno == EMFILE || errno == ENFILE) 1929 c->notbefore = monotime() + 1; 1930 return; 1931 } 1932 if (c->host_port != PORT_STREAMLOCAL) 1933 set_nodelay(newsock); 1934 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1935 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1936 nc->listening_port = c->listening_port; 1937 nc->host_port = c->host_port; 1938 if (c->path != NULL) 1939 nc->path = xstrdup(c->path); 1940 1941 if (nextstate != SSH_CHANNEL_DYNAMIC) 1942 port_open_helper(ssh, nc, rtype); 1943 } 1944 1945 /* 1946 * This is the authentication agent socket listening for connections from 1947 * clients. 1948 */ 1949 static void 1950 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1951 { 1952 Channel *nc; 1953 int r, newsock; 1954 struct sockaddr_storage addr; 1955 socklen_t addrlen; 1956 1957 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1958 return; 1959 1960 addrlen = sizeof(addr); 1961 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1962 if (newsock == -1) { 1963 error("accept from auth socket: %.100s", strerror(errno)); 1964 if (errno == EMFILE || errno == ENFILE) 1965 c->notbefore = monotime() + 1; 1966 return; 1967 } 1968 nc = channel_new(ssh, "agent-connection", 1969 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1970 c->local_window_max, c->local_maxpacket, 1971 0, "accepted auth socket", 1); 1972 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1973 if ((r = sshpkt_send(ssh)) != 0) 1974 fatal_fr(r, "channel %i", c->self); 1975 } 1976 1977 static void 1978 channel_post_connecting(struct ssh *ssh, Channel *c) 1979 { 1980 int err = 0, sock, isopen, r; 1981 socklen_t sz = sizeof(err); 1982 1983 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 1984 return; 1985 if (!c->have_remote_id) 1986 fatal_f("channel %d: no remote id", c->self); 1987 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1988 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1989 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 1990 err = errno; 1991 error("getsockopt SO_ERROR failed"); 1992 } 1993 if (err == 0) { 1994 debug("channel %d: connected to %s port %d", 1995 c->self, c->connect_ctx.host, c->connect_ctx.port); 1996 channel_connect_ctx_free(&c->connect_ctx); 1997 c->type = SSH_CHANNEL_OPEN; 1998 c->lastused = monotime(); 1999 if (isopen) { 2000 /* no message necessary */ 2001 } else { 2002 if ((r = sshpkt_start(ssh, 2003 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2004 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2005 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2006 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2007 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2008 (r = sshpkt_send(ssh)) != 0) 2009 fatal_fr(r, "channel %i open confirm", c->self); 2010 } 2011 } else { 2012 debug("channel %d: connection failed: %s", 2013 c->self, strerror(err)); 2014 /* Try next address, if any */ 2015 if ((sock = connect_next(&c->connect_ctx)) > 0) { 2016 close(c->sock); 2017 c->sock = c->rfd = c->wfd = sock; 2018 return; 2019 } 2020 /* Exhausted all addresses */ 2021 error("connect_to %.100s port %d: failed.", 2022 c->connect_ctx.host, c->connect_ctx.port); 2023 channel_connect_ctx_free(&c->connect_ctx); 2024 if (isopen) { 2025 rdynamic_close(ssh, c); 2026 } else { 2027 if ((r = sshpkt_start(ssh, 2028 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2029 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2030 (r = sshpkt_put_u32(ssh, 2031 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2032 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2033 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2034 (r = sshpkt_send(ssh)) != 0) 2035 fatal_fr(r, "channel %i: failure", c->self); 2036 chan_mark_dead(ssh, c); 2037 } 2038 } 2039 } 2040 2041 static int 2042 channel_handle_rfd(struct ssh *ssh, Channel *c) 2043 { 2044 char buf[CHAN_RBUF]; 2045 ssize_t len; 2046 int r, force; 2047 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2048 int pty_zeroread = 0; 2049 2050 #ifdef PTY_ZEROREAD 2051 /* Bug on AIX: read(1) can return 0 for a non-closed fd */ 2052 pty_zeroread = c->isatty; 2053 #endif 2054 2055 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2056 2057 if (!force && (c->io_ready & SSH_CHAN_IO_RFD) == 0) 2058 return 1; 2059 if ((avail = sshbuf_avail(c->input)) == 0) 2060 return 1; /* Shouldn't happen */ 2061 2062 /* 2063 * For "simple" channels (i.e. not datagram or filtered), we can 2064 * read directly to the channel buffer. 2065 */ 2066 if (!pty_zeroread && c->input_filter == NULL && !c->datagram) { 2067 /* Only OPEN channels have valid rwin */ 2068 if (c->type == SSH_CHANNEL_OPEN) { 2069 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2070 return 1; /* shouldn't happen */ 2071 if (maxlen > c->remote_window - have) 2072 maxlen = c->remote_window - have; 2073 } 2074 if (maxlen > avail) 2075 maxlen = avail; 2076 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2077 if (errno == EINTR || (!force && 2078 (errno == EAGAIN || errno == EWOULDBLOCK))) 2079 return 1; 2080 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2081 c->self, c->rfd, maxlen, ssh_err(r)); 2082 goto rfail; 2083 } 2084 if (nr != 0) 2085 c->lastused = monotime(); 2086 return 1; 2087 } 2088 2089 errno = 0; 2090 len = read(c->rfd, buf, sizeof(buf)); 2091 /* fixup AIX zero-length read with errno set to look more like errors */ 2092 if (pty_zeroread && len == 0 && errno != 0) 2093 len = -1; 2094 if (len == -1 && (errno == EINTR || 2095 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 2096 return 1; 2097 if (len < 0 || (!pty_zeroread && len == 0)) { 2098 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2099 c->self, c->rfd, len, 2100 len == 0 ? "closed" : strerror(errno)); 2101 rfail: 2102 if (c->type != SSH_CHANNEL_OPEN) { 2103 debug2("channel %d: not open", c->self); 2104 chan_mark_dead(ssh, c); 2105 return -1; 2106 } else { 2107 chan_read_failed(ssh, c); 2108 } 2109 return -1; 2110 } 2111 c->lastused = monotime(); 2112 if (c->input_filter != NULL) { 2113 if (c->input_filter(ssh, c, buf, len) == -1) { 2114 debug2("channel %d: filter stops", c->self); 2115 chan_read_failed(ssh, c); 2116 } 2117 } else if (c->datagram) { 2118 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2119 fatal_fr(r, "channel %i: put datagram", c->self); 2120 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2121 fatal_fr(r, "channel %i: put data", c->self); 2122 2123 return 1; 2124 } 2125 2126 static int 2127 channel_handle_wfd(struct ssh *ssh, Channel *c) 2128 { 2129 struct termios tio; 2130 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2131 size_t dlen, olen = 0; 2132 int r, len; 2133 2134 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2135 return 1; 2136 if (sshbuf_len(c->output) == 0) 2137 return 1; 2138 2139 /* Send buffered output data to the socket. */ 2140 olen = sshbuf_len(c->output); 2141 if (c->output_filter != NULL) { 2142 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2143 debug2("channel %d: filter stops", c->self); 2144 if (c->type != SSH_CHANNEL_OPEN) 2145 chan_mark_dead(ssh, c); 2146 else 2147 chan_write_failed(ssh, c); 2148 return -1; 2149 } 2150 } else if (c->datagram) { 2151 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2152 fatal_fr(r, "channel %i: get datagram", c->self); 2153 buf = data; 2154 } else { 2155 buf = data = sshbuf_mutable_ptr(c->output); 2156 dlen = sshbuf_len(c->output); 2157 } 2158 2159 if (c->datagram) { 2160 /* ignore truncated writes, datagrams might get lost */ 2161 len = write(c->wfd, buf, dlen); 2162 free(data); 2163 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2164 errno == EWOULDBLOCK)) 2165 return 1; 2166 if (len <= 0) 2167 goto write_fail; 2168 goto out; 2169 } 2170 2171 #ifdef _AIX 2172 /* XXX: Later AIX versions can't push as much data to tty */ 2173 if (c->wfd_isatty) 2174 dlen = MINIMUM(dlen, 8*1024); 2175 #endif 2176 2177 len = write(c->wfd, buf, dlen); 2178 if (len == -1 && 2179 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 2180 return 1; 2181 if (len <= 0) { 2182 write_fail: 2183 if (c->type != SSH_CHANNEL_OPEN) { 2184 debug2("channel %d: not open", c->self); 2185 chan_mark_dead(ssh, c); 2186 return -1; 2187 } else { 2188 chan_write_failed(ssh, c); 2189 } 2190 return -1; 2191 } 2192 c->lastused = monotime(); 2193 #ifndef BROKEN_TCGETATTR_ICANON 2194 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2195 if (tcgetattr(c->wfd, &tio) == 0 && 2196 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2197 /* 2198 * Simulate echo to reduce the impact of 2199 * traffic analysis. We need to match the 2200 * size of a SSH2_MSG_CHANNEL_DATA message 2201 * (4 byte channel id + buf) 2202 */ 2203 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2204 (r = sshpkt_send(ssh)) != 0) 2205 fatal_fr(r, "channel %i: ignore", c->self); 2206 } 2207 } 2208 #endif /* BROKEN_TCGETATTR_ICANON */ 2209 if ((r = sshbuf_consume(c->output, len)) != 0) 2210 fatal_fr(r, "channel %i: consume", c->self); 2211 out: 2212 c->local_consumed += olen - sshbuf_len(c->output); 2213 2214 return 1; 2215 } 2216 2217 static int 2218 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2219 { 2220 int r; 2221 ssize_t len; 2222 2223 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2224 return 1; 2225 if (sshbuf_len(c->extended) == 0) 2226 return 1; 2227 2228 len = write(c->efd, sshbuf_ptr(c->extended), 2229 sshbuf_len(c->extended)); 2230 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2231 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2232 errno == EWOULDBLOCK)) 2233 return 1; 2234 if (len <= 0) { 2235 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2236 channel_close_fd(ssh, c, &c->efd); 2237 } else { 2238 if ((r = sshbuf_consume(c->extended, len)) != 0) 2239 fatal_fr(r, "channel %i: consume", c->self); 2240 c->local_consumed += len; 2241 c->lastused = monotime(); 2242 } 2243 return 1; 2244 } 2245 2246 static int 2247 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2248 { 2249 char buf[CHAN_RBUF]; 2250 ssize_t len; 2251 int r, force; 2252 2253 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2254 2255 if (!force && (c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2256 return 1; 2257 2258 len = read(c->efd, buf, sizeof(buf)); 2259 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2260 if (len == -1 && (errno == EINTR || ((errno == EAGAIN || 2261 errno == EWOULDBLOCK) && !force))) 2262 return 1; 2263 if (len <= 0) { 2264 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2265 channel_close_fd(ssh, c, &c->efd); 2266 return 1; 2267 } 2268 c->lastused = monotime(); 2269 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2270 debug3("channel %d: discard efd", c->self); 2271 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2272 fatal_fr(r, "channel %i: append", c->self); 2273 return 1; 2274 } 2275 2276 static int 2277 channel_handle_efd(struct ssh *ssh, Channel *c) 2278 { 2279 if (c->efd == -1) 2280 return 1; 2281 2282 /** XXX handle drain efd, too */ 2283 2284 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2285 return channel_handle_efd_write(ssh, c); 2286 else if (c->extended_usage == CHAN_EXTENDED_READ || 2287 c->extended_usage == CHAN_EXTENDED_IGNORE) 2288 return channel_handle_efd_read(ssh, c); 2289 2290 return 1; 2291 } 2292 2293 static int 2294 channel_check_window(struct ssh *ssh, Channel *c) 2295 { 2296 int r; 2297 2298 if (c->type == SSH_CHANNEL_OPEN && 2299 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2300 ((c->local_window_max - c->local_window > 2301 c->local_maxpacket*3) || 2302 c->local_window < c->local_window_max/2) && 2303 c->local_consumed > 0) { 2304 if (!c->have_remote_id) 2305 fatal_f("channel %d: no remote id", c->self); 2306 if ((r = sshpkt_start(ssh, 2307 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2308 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2309 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2310 (r = sshpkt_send(ssh)) != 0) { 2311 fatal_fr(r, "channel %i", c->self); 2312 } 2313 debug2("channel %d: window %d sent adjust %d", c->self, 2314 c->local_window, c->local_consumed); 2315 c->local_window += c->local_consumed; 2316 c->local_consumed = 0; 2317 } 2318 return 1; 2319 } 2320 2321 static void 2322 channel_post_open(struct ssh *ssh, Channel *c) 2323 { 2324 channel_handle_rfd(ssh, c); 2325 channel_handle_wfd(ssh, c); 2326 channel_handle_efd(ssh, c); 2327 channel_check_window(ssh, c); 2328 } 2329 2330 static u_int 2331 read_mux(struct ssh *ssh, Channel *c, u_int need) 2332 { 2333 char buf[CHAN_RBUF]; 2334 ssize_t len; 2335 u_int rlen; 2336 int r; 2337 2338 if (sshbuf_len(c->input) < need) { 2339 rlen = need - sshbuf_len(c->input); 2340 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2341 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2342 return sshbuf_len(c->input); 2343 if (len <= 0) { 2344 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2345 c->self, c->rfd, len); 2346 chan_read_failed(ssh, c); 2347 return 0; 2348 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2349 fatal_fr(r, "channel %i: append", c->self); 2350 } 2351 return sshbuf_len(c->input); 2352 } 2353 2354 static void 2355 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2356 { 2357 u_int need; 2358 2359 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2360 return; 2361 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2362 return; 2363 if (c->mux_pause) 2364 return; 2365 2366 /* 2367 * Don't not read past the precise end of packets to 2368 * avoid disrupting fd passing. 2369 */ 2370 if (read_mux(ssh, c, 4) < 4) /* read header */ 2371 return; 2372 /* XXX sshbuf_peek_u32 */ 2373 need = PEEK_U32(sshbuf_ptr(c->input)); 2374 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2375 if (need > CHANNEL_MUX_MAX_PACKET) { 2376 debug2("channel %d: packet too big %u > %u", 2377 c->self, CHANNEL_MUX_MAX_PACKET, need); 2378 chan_rcvd_oclose(ssh, c); 2379 return; 2380 } 2381 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2382 return; 2383 if (c->mux_rcb(ssh, c) != 0) { 2384 debug("channel %d: mux_rcb failed", c->self); 2385 chan_mark_dead(ssh, c); 2386 return; 2387 } 2388 } 2389 2390 static void 2391 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2392 { 2393 ssize_t len; 2394 int r; 2395 2396 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2397 return; 2398 if (sshbuf_len(c->output) == 0) 2399 return; 2400 2401 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2402 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2403 return; 2404 if (len <= 0) { 2405 chan_mark_dead(ssh, c); 2406 return; 2407 } 2408 if ((r = sshbuf_consume(c->output, len)) != 0) 2409 fatal_fr(r, "channel %i: consume", c->self); 2410 } 2411 2412 static void 2413 channel_post_mux_client(struct ssh *ssh, Channel *c) 2414 { 2415 channel_post_mux_client_read(ssh, c); 2416 channel_post_mux_client_write(ssh, c); 2417 } 2418 2419 static void 2420 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2421 { 2422 Channel *nc; 2423 struct sockaddr_storage addr; 2424 socklen_t addrlen; 2425 int newsock; 2426 uid_t euid; 2427 gid_t egid; 2428 2429 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2430 return; 2431 2432 debug("multiplexing control connection"); 2433 2434 /* 2435 * Accept connection on control socket 2436 */ 2437 memset(&addr, 0, sizeof(addr)); 2438 addrlen = sizeof(addr); 2439 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2440 &addrlen)) == -1) { 2441 error_f("accept: %s", strerror(errno)); 2442 if (errno == EMFILE || errno == ENFILE) 2443 c->notbefore = monotime() + 1; 2444 return; 2445 } 2446 2447 if (getpeereid(newsock, &euid, &egid) == -1) { 2448 error_f("getpeereid failed: %s", strerror(errno)); 2449 close(newsock); 2450 return; 2451 } 2452 if ((euid != 0) && (getuid() != euid)) { 2453 error("multiplex uid mismatch: peer euid %u != uid %u", 2454 (u_int)euid, (u_int)getuid()); 2455 close(newsock); 2456 return; 2457 } 2458 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2459 newsock, newsock, -1, c->local_window_max, 2460 c->local_maxpacket, 0, "mux-control", 1); 2461 nc->mux_rcb = c->mux_rcb; 2462 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2463 /* establish state */ 2464 nc->mux_rcb(ssh, nc); 2465 /* mux state transitions must not elicit protocol messages */ 2466 nc->flags |= CHAN_LOCAL; 2467 } 2468 2469 static void 2470 channel_handler_init(struct ssh_channels *sc) 2471 { 2472 chan_fn **pre, **post; 2473 2474 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2475 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2476 fatal_f("allocation failed"); 2477 2478 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2479 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2480 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2481 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2482 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2483 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2484 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2485 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2486 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2487 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2488 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2489 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2490 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2491 2492 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2493 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2494 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2495 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2496 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2497 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2498 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2499 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2500 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2501 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2502 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2503 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2504 2505 sc->channel_pre = pre; 2506 sc->channel_post = post; 2507 } 2508 2509 /* gc dead channels */ 2510 static void 2511 channel_garbage_collect(struct ssh *ssh, Channel *c) 2512 { 2513 if (c == NULL) 2514 return; 2515 if (c->detach_user != NULL) { 2516 if (!chan_is_dead(ssh, c, c->detach_close)) 2517 return; 2518 2519 debug2("channel %d: gc: notify user", c->self); 2520 c->detach_user(ssh, c->self, 0, NULL); 2521 /* if we still have a callback */ 2522 if (c->detach_user != NULL) 2523 return; 2524 debug2("channel %d: gc: user detached", c->self); 2525 } 2526 if (!chan_is_dead(ssh, c, 1)) 2527 return; 2528 debug2("channel %d: garbage collecting", c->self); 2529 channel_free(ssh, c); 2530 } 2531 2532 enum channel_table { CHAN_PRE, CHAN_POST }; 2533 2534 static void 2535 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2536 { 2537 struct ssh_channels *sc = ssh->chanctxt; 2538 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2539 u_int i, oalloc; 2540 Channel *c; 2541 time_t now; 2542 2543 now = monotime(); 2544 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2545 c = sc->channels[i]; 2546 if (c == NULL) 2547 continue; 2548 /* Try to keep IO going while rekeying */ 2549 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2550 continue; 2551 if (c->delayed) { 2552 if (table == CHAN_PRE) 2553 c->delayed = 0; 2554 else 2555 continue; 2556 } 2557 if (ftab[c->type] != NULL) { 2558 if (table == CHAN_PRE && 2559 c->type == SSH_CHANNEL_OPEN && 2560 c->inactive_deadline != 0 && c->lastused != 0 && 2561 now >= c->lastused + c->inactive_deadline) { 2562 /* channel closed for inactivity */ 2563 verbose("channel %d: closing after %u seconds " 2564 "of inactivity", c->self, 2565 c->inactive_deadline); 2566 channel_force_close(ssh, c, 1); 2567 } else if (c->notbefore <= now) { 2568 /* Run handlers that are not paused. */ 2569 (*ftab[c->type])(ssh, c); 2570 /* inactivity timeouts must interrupt poll() */ 2571 if (timeout != NULL && 2572 c->type == SSH_CHANNEL_OPEN && 2573 c->lastused != 0 && 2574 c->inactive_deadline != 0) { 2575 ptimeout_deadline_monotime(timeout, 2576 c->lastused + c->inactive_deadline); 2577 } 2578 } else if (timeout != NULL) { 2579 /* 2580 * Arrange for poll() wakeup when channel pause 2581 * timer expires. 2582 */ 2583 ptimeout_deadline_monotime(timeout, 2584 c->notbefore); 2585 } 2586 } 2587 channel_garbage_collect(ssh, c); 2588 } 2589 } 2590 2591 /* 2592 * Create sockets before preparing IO. 2593 * This is necessary for things that need to happen after reading 2594 * the network-input but need to be completed before IO event setup, e.g. 2595 * because they may create new channels. 2596 */ 2597 static void 2598 channel_before_prepare_io(struct ssh *ssh) 2599 { 2600 struct ssh_channels *sc = ssh->chanctxt; 2601 Channel *c; 2602 u_int i, oalloc; 2603 2604 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2605 c = sc->channels[i]; 2606 if (c == NULL) 2607 continue; 2608 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2609 channel_before_prepare_io_rdynamic(ssh, c); 2610 } 2611 } 2612 2613 static void 2614 dump_channel_poll(const char *func, const char *what, Channel *c, 2615 u_int pollfd_offset, struct pollfd *pfd) 2616 { 2617 #ifdef DEBUG_CHANNEL_POLL 2618 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2619 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2620 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2621 c->rfd, c->wfd, c->efd, c->sock, 2622 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2623 c->io_want, c->io_ready, 2624 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2625 #endif 2626 } 2627 2628 /* Prepare pollfd entries for a single channel */ 2629 static void 2630 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2631 struct pollfd *pfd, u_int npfd) 2632 { 2633 u_int ev, p = *next_pollfd; 2634 2635 if (c == NULL) 2636 return; 2637 if (p + 4 > npfd) { 2638 /* Shouldn't happen */ 2639 fatal_f("channel %d: bad pfd offset %u (max %u)", 2640 c->self, p, npfd); 2641 } 2642 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2643 /* 2644 * prepare c->rfd 2645 * 2646 * This is a special case, since c->rfd might be the same as 2647 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2648 * IO too. 2649 */ 2650 if (c->rfd != -1) { 2651 ev = 0; 2652 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2653 ev |= POLLIN; 2654 /* rfd == wfd */ 2655 if (c->wfd == c->rfd) { 2656 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2657 ev |= POLLOUT; 2658 } 2659 /* rfd == efd */ 2660 if (c->efd == c->rfd) { 2661 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2662 ev |= POLLIN; 2663 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2664 ev |= POLLOUT; 2665 } 2666 /* rfd == sock */ 2667 if (c->sock == c->rfd) { 2668 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2669 ev |= POLLIN; 2670 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2671 ev |= POLLOUT; 2672 } 2673 /* Pack a pfd entry if any event armed for this fd */ 2674 if (ev != 0) { 2675 c->pfds[0] = p; 2676 pfd[p].fd = c->rfd; 2677 pfd[p].events = ev; 2678 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2679 p++; 2680 } 2681 } 2682 /* prepare c->wfd if wanting IO and not already handled above */ 2683 if (c->wfd != -1 && c->rfd != c->wfd) { 2684 ev = 0; 2685 if ((c->io_want & SSH_CHAN_IO_WFD)) 2686 ev |= POLLOUT; 2687 /* Pack a pfd entry if any event armed for this fd */ 2688 if (ev != 0) { 2689 c->pfds[1] = p; 2690 pfd[p].fd = c->wfd; 2691 pfd[p].events = ev; 2692 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2693 p++; 2694 } 2695 } 2696 /* prepare c->efd if wanting IO and not already handled above */ 2697 if (c->efd != -1 && c->rfd != c->efd) { 2698 ev = 0; 2699 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2700 ev |= POLLIN; 2701 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2702 ev |= POLLOUT; 2703 /* Pack a pfd entry if any event armed for this fd */ 2704 if (ev != 0) { 2705 c->pfds[2] = p; 2706 pfd[p].fd = c->efd; 2707 pfd[p].events = ev; 2708 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2709 p++; 2710 } 2711 } 2712 /* prepare c->sock if wanting IO and not already handled above */ 2713 if (c->sock != -1 && c->rfd != c->sock) { 2714 ev = 0; 2715 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2716 ev |= POLLIN; 2717 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2718 ev |= POLLOUT; 2719 /* Pack a pfd entry if any event armed for this fd */ 2720 if (ev != 0) { 2721 c->pfds[3] = p; 2722 pfd[p].fd = c->sock; 2723 pfd[p].events = 0; 2724 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2725 p++; 2726 } 2727 } 2728 *next_pollfd = p; 2729 } 2730 2731 /* * Allocate/prepare poll structure */ 2732 void 2733 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2734 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2735 { 2736 struct ssh_channels *sc = ssh->chanctxt; 2737 u_int i, oalloc, p, npfd = npfd_reserved; 2738 2739 channel_before_prepare_io(ssh); /* might create a new channel */ 2740 /* clear out I/O flags from last poll */ 2741 for (i = 0; i < sc->channels_alloc; i++) { 2742 if (sc->channels[i] == NULL) 2743 continue; 2744 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2745 } 2746 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2747 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2748 fatal_f("too many channels"); /* shouldn't happen */ 2749 npfd += sc->channels_alloc * 4; 2750 if (npfd > *npfd_allocp) { 2751 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2752 npfd, sizeof(**pfdp)); 2753 *npfd_allocp = npfd; 2754 } 2755 *npfd_activep = npfd_reserved; 2756 oalloc = sc->channels_alloc; 2757 2758 channel_handler(ssh, CHAN_PRE, timeout); 2759 2760 if (oalloc != sc->channels_alloc) { 2761 /* shouldn't happen */ 2762 fatal_f("channels_alloc changed during CHAN_PRE " 2763 "(was %u, now %u)", oalloc, sc->channels_alloc); 2764 } 2765 2766 /* Prepare pollfd */ 2767 p = npfd_reserved; 2768 for (i = 0; i < sc->channels_alloc; i++) 2769 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2770 *npfd_activep = p; 2771 } 2772 2773 static void 2774 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2775 const char *what, u_int revents_mask, u_int ready) 2776 { 2777 struct pollfd *pfd = &pfds[p]; 2778 2779 if (fd == -1) 2780 return; 2781 if (p == -1 || (u_int)p >= npfd) 2782 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2783 dump_channel_poll(__func__, what, c, p, pfd); 2784 if (pfd->fd != fd) { 2785 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2786 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2787 c->rfd, c->wfd, c->efd, c->sock); 2788 } 2789 if ((pfd->revents & POLLNVAL) != 0) { 2790 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2791 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2792 } 2793 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2794 c->io_ready |= ready & c->io_want; 2795 } 2796 2797 /* 2798 * After poll, perform any appropriate operations for channels which have 2799 * events pending. 2800 */ 2801 void 2802 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2803 { 2804 struct ssh_channels *sc = ssh->chanctxt; 2805 u_int i; 2806 int p; 2807 Channel *c; 2808 2809 #ifdef DEBUG_CHANNEL_POLL 2810 for (p = 0; p < (int)npfd; p++) { 2811 if (pfd[p].revents == 0) 2812 continue; 2813 debug_f("pfd[%u].fd %d rev 0x%04x", 2814 p, pfd[p].fd, pfd[p].revents); 2815 } 2816 #endif 2817 2818 /* Convert pollfd into c->io_ready */ 2819 for (i = 0; i < sc->channels_alloc; i++) { 2820 c = sc->channels[i]; 2821 if (c == NULL) 2822 continue; 2823 /* if rfd is shared with efd/sock then wfd should be too */ 2824 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2825 (c->rfd == c->efd || c->rfd == c->sock)) { 2826 /* Shouldn't happen */ 2827 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2828 c->self, c->rfd, c->wfd, c->efd, c->sock); 2829 } 2830 c->io_ready = 0; 2831 /* rfd, potentially shared with wfd, efd and sock */ 2832 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2833 fd_ready(c, p, pfd, npfd, c->rfd, 2834 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2835 if (c->rfd == c->wfd) { 2836 fd_ready(c, p, pfd, npfd, c->wfd, 2837 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2838 } 2839 if (c->rfd == c->efd) { 2840 fd_ready(c, p, pfd, npfd, c->efd, 2841 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2842 fd_ready(c, p, pfd, npfd, c->efd, 2843 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2844 } 2845 if (c->rfd == c->sock) { 2846 fd_ready(c, p, pfd, npfd, c->sock, 2847 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2848 fd_ready(c, p, pfd, npfd, c->sock, 2849 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2850 } 2851 dump_channel_poll(__func__, "rfd", c, p, pfd); 2852 } 2853 /* wfd */ 2854 if (c->wfd != -1 && c->wfd != c->rfd && 2855 (p = c->pfds[1]) != -1) { 2856 fd_ready(c, p, pfd, npfd, c->wfd, 2857 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2858 dump_channel_poll(__func__, "wfd", c, p, pfd); 2859 } 2860 /* efd */ 2861 if (c->efd != -1 && c->efd != c->rfd && 2862 (p = c->pfds[2]) != -1) { 2863 fd_ready(c, p, pfd, npfd, c->efd, 2864 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2865 fd_ready(c, p, pfd, npfd, c->efd, 2866 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2867 dump_channel_poll(__func__, "efd", c, p, pfd); 2868 } 2869 /* sock */ 2870 if (c->sock != -1 && c->sock != c->rfd && 2871 (p = c->pfds[3]) != -1) { 2872 fd_ready(c, p, pfd, npfd, c->sock, 2873 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2874 fd_ready(c, p, pfd, npfd, c->sock, 2875 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2876 dump_channel_poll(__func__, "sock", c, p, pfd); 2877 } 2878 } 2879 channel_handler(ssh, CHAN_POST, NULL); 2880 } 2881 2882 /* 2883 * Enqueue data for channels with open or draining c->input. 2884 */ 2885 static void 2886 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2887 { 2888 size_t len, plen; 2889 const u_char *pkt; 2890 int r; 2891 2892 if ((len = sshbuf_len(c->input)) == 0) { 2893 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2894 /* 2895 * input-buffer is empty and read-socket shutdown: 2896 * tell peer, that we will not send more data: 2897 * send IEOF. 2898 * hack for extended data: delay EOF if EFD still 2899 * in use. 2900 */ 2901 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2902 debug2("channel %d: " 2903 "ibuf_empty delayed efd %d/(%zu)", 2904 c->self, c->efd, sshbuf_len(c->extended)); 2905 else 2906 chan_ibuf_empty(ssh, c); 2907 } 2908 return; 2909 } 2910 2911 if (!c->have_remote_id) 2912 fatal_f("channel %d: no remote id", c->self); 2913 2914 if (c->datagram) { 2915 /* Check datagram will fit; drop if not */ 2916 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2917 fatal_fr(r, "channel %i: get datagram", c->self); 2918 /* 2919 * XXX this does tail-drop on the datagram queue which is 2920 * usually suboptimal compared to head-drop. Better to have 2921 * backpressure at read time? (i.e. read + discard) 2922 */ 2923 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2924 debug("channel %d: datagram too big", c->self); 2925 return; 2926 } 2927 /* Enqueue it */ 2928 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2929 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2930 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2931 (r = sshpkt_send(ssh)) != 0) 2932 fatal_fr(r, "channel %i: send datagram", c->self); 2933 c->remote_window -= plen; 2934 return; 2935 } 2936 2937 /* Enqueue packet for buffered data. */ 2938 if (len > c->remote_window) 2939 len = c->remote_window; 2940 if (len > c->remote_maxpacket) 2941 len = c->remote_maxpacket; 2942 if (len == 0) 2943 return; 2944 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2945 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2946 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2947 (r = sshpkt_send(ssh)) != 0) 2948 fatal_fr(r, "channel %i: send data", c->self); 2949 if ((r = sshbuf_consume(c->input, len)) != 0) 2950 fatal_fr(r, "channel %i: consume", c->self); 2951 c->remote_window -= len; 2952 } 2953 2954 /* 2955 * Enqueue data for channels with open c->extended in read mode. 2956 */ 2957 static void 2958 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2959 { 2960 size_t len; 2961 int r; 2962 2963 if ((len = sshbuf_len(c->extended)) == 0) 2964 return; 2965 2966 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2967 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2968 if (len > c->remote_window) 2969 len = c->remote_window; 2970 if (len > c->remote_maxpacket) 2971 len = c->remote_maxpacket; 2972 if (len == 0) 2973 return; 2974 if (!c->have_remote_id) 2975 fatal_f("channel %d: no remote id", c->self); 2976 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2977 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2978 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2979 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2980 (r = sshpkt_send(ssh)) != 0) 2981 fatal_fr(r, "channel %i: data", c->self); 2982 if ((r = sshbuf_consume(c->extended, len)) != 0) 2983 fatal_fr(r, "channel %i: consume", c->self); 2984 c->remote_window -= len; 2985 debug2("channel %d: sent ext data %zu", c->self, len); 2986 } 2987 2988 /* If there is data to send to the connection, enqueue some of it now. */ 2989 void 2990 channel_output_poll(struct ssh *ssh) 2991 { 2992 struct ssh_channels *sc = ssh->chanctxt; 2993 Channel *c; 2994 u_int i; 2995 2996 for (i = 0; i < sc->channels_alloc; i++) { 2997 c = sc->channels[i]; 2998 if (c == NULL) 2999 continue; 3000 3001 /* 3002 * We are only interested in channels that can have buffered 3003 * incoming data. 3004 */ 3005 if (c->type != SSH_CHANNEL_OPEN) 3006 continue; 3007 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3008 /* XXX is this true? */ 3009 debug3("channel %d: will not send data after close", 3010 c->self); 3011 continue; 3012 } 3013 3014 /* Get the amount of buffered data for this channel. */ 3015 if (c->istate == CHAN_INPUT_OPEN || 3016 c->istate == CHAN_INPUT_WAIT_DRAIN) 3017 channel_output_poll_input_open(ssh, c); 3018 /* Send extended data, i.e. stderr */ 3019 if (!(c->flags & CHAN_EOF_SENT) && 3020 c->extended_usage == CHAN_EXTENDED_READ) 3021 channel_output_poll_extended_read(ssh, c); 3022 } 3023 } 3024 3025 /* -- mux proxy support */ 3026 3027 /* 3028 * When multiplexing channel messages for mux clients we have to deal 3029 * with downstream messages from the mux client and upstream messages 3030 * from the ssh server: 3031 * 1) Handling downstream messages is straightforward and happens 3032 * in channel_proxy_downstream(): 3033 * - We forward all messages (mostly) unmodified to the server. 3034 * - However, in order to route messages from upstream to the correct 3035 * downstream client, we have to replace the channel IDs used by the 3036 * mux clients with a unique channel ID because the mux clients might 3037 * use conflicting channel IDs. 3038 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3039 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3040 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3041 * with the newly allocated channel ID. 3042 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3043 * channels and processed by channel_proxy_upstream(). The local channel ID 3044 * is then translated back to the original mux client ID. 3045 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3046 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3047 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3048 * downstream mux client are removed. 3049 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3050 * requires more work, because they are not addressed to a specific 3051 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3052 * out whether the request is addressed to the local client or a 3053 * specific downstream client based on the listen-address/port. 3054 * 6) Agent and X11-Forwarding have a similar problem and are currently 3055 * not supported as the matching session/channel cannot be identified 3056 * easily. 3057 */ 3058 3059 /* 3060 * receive packets from downstream mux clients: 3061 * channel callback fired on read from mux client, creates 3062 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3063 * on channel creation. 3064 */ 3065 int 3066 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3067 { 3068 Channel *c = NULL; 3069 struct sshbuf *original = NULL, *modified = NULL; 3070 const u_char *cp; 3071 char *ctype = NULL, *listen_host = NULL; 3072 u_char type; 3073 size_t have; 3074 int ret = -1, r; 3075 u_int id, remote_id, listen_port; 3076 3077 /* sshbuf_dump(downstream->input, stderr); */ 3078 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3079 != 0) { 3080 error_fr(r, "parse"); 3081 return -1; 3082 } 3083 if (have < 2) { 3084 error_f("short message"); 3085 return -1; 3086 } 3087 type = cp[1]; 3088 /* skip padlen + type */ 3089 cp += 2; 3090 have -= 2; 3091 if (ssh_packet_log_type(type)) 3092 debug3_f("channel %u: down->up: type %u", 3093 downstream->self, type); 3094 3095 switch (type) { 3096 case SSH2_MSG_CHANNEL_OPEN: 3097 if ((original = sshbuf_from(cp, have)) == NULL || 3098 (modified = sshbuf_new()) == NULL) { 3099 error_f("alloc"); 3100 goto out; 3101 } 3102 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3103 (r = sshbuf_get_u32(original, &id)) != 0) { 3104 error_fr(r, "parse"); 3105 goto out; 3106 } 3107 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3108 -1, -1, -1, 0, 0, 0, ctype, 1); 3109 c->mux_ctx = downstream; /* point to mux client */ 3110 c->mux_downstream_id = id; /* original downstream id */ 3111 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3112 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3113 (r = sshbuf_putb(modified, original)) != 0) { 3114 error_fr(r, "compose"); 3115 channel_free(ssh, c); 3116 goto out; 3117 } 3118 break; 3119 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3120 /* 3121 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3122 * need to parse 'remote_id' instead of 'ctype'. 3123 */ 3124 if ((original = sshbuf_from(cp, have)) == NULL || 3125 (modified = sshbuf_new()) == NULL) { 3126 error_f("alloc"); 3127 goto out; 3128 } 3129 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3130 (r = sshbuf_get_u32(original, &id)) != 0) { 3131 error_fr(r, "parse"); 3132 goto out; 3133 } 3134 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3135 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3136 c->mux_ctx = downstream; /* point to mux client */ 3137 c->mux_downstream_id = id; 3138 c->remote_id = remote_id; 3139 c->have_remote_id = 1; 3140 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3141 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3142 (r = sshbuf_putb(modified, original)) != 0) { 3143 error_fr(r, "compose"); 3144 channel_free(ssh, c); 3145 goto out; 3146 } 3147 break; 3148 case SSH2_MSG_GLOBAL_REQUEST: 3149 if ((original = sshbuf_from(cp, have)) == NULL) { 3150 error_f("alloc"); 3151 goto out; 3152 } 3153 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3154 error_fr(r, "parse"); 3155 goto out; 3156 } 3157 if (strcmp(ctype, "tcpip-forward") != 0) { 3158 error_f("unsupported request %s", ctype); 3159 goto out; 3160 } 3161 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3162 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3163 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3164 error_fr(r, "parse"); 3165 goto out; 3166 } 3167 if (listen_port > 65535) { 3168 error_f("tcpip-forward for %s: bad port %u", 3169 listen_host, listen_port); 3170 goto out; 3171 } 3172 /* Record that connection to this host/port is permitted. */ 3173 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 3174 listen_host, NULL, (int)listen_port, downstream); 3175 listen_host = NULL; 3176 break; 3177 case SSH2_MSG_CHANNEL_CLOSE: 3178 if (have < 4) 3179 break; 3180 remote_id = PEEK_U32(cp); 3181 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3182 if (c->flags & CHAN_CLOSE_RCVD) 3183 channel_free(ssh, c); 3184 else 3185 c->flags |= CHAN_CLOSE_SENT; 3186 } 3187 break; 3188 } 3189 if (modified) { 3190 if ((r = sshpkt_start(ssh, type)) != 0 || 3191 (r = sshpkt_putb(ssh, modified)) != 0 || 3192 (r = sshpkt_send(ssh)) != 0) { 3193 error_fr(r, "send"); 3194 goto out; 3195 } 3196 } else { 3197 if ((r = sshpkt_start(ssh, type)) != 0 || 3198 (r = sshpkt_put(ssh, cp, have)) != 0 || 3199 (r = sshpkt_send(ssh)) != 0) { 3200 error_fr(r, "send"); 3201 goto out; 3202 } 3203 } 3204 ret = 0; 3205 out: 3206 free(ctype); 3207 free(listen_host); 3208 sshbuf_free(original); 3209 sshbuf_free(modified); 3210 return ret; 3211 } 3212 3213 /* 3214 * receive packets from upstream server and de-multiplex packets 3215 * to correct downstream: 3216 * implemented as a helper for channel input handlers, 3217 * replaces local (proxy) channel ID with downstream channel ID. 3218 */ 3219 int 3220 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3221 { 3222 struct sshbuf *b = NULL; 3223 Channel *downstream; 3224 const u_char *cp = NULL; 3225 size_t len; 3226 int r; 3227 3228 /* 3229 * When receiving packets from the peer we need to check whether we 3230 * need to forward the packets to the mux client. In this case we 3231 * restore the original channel id and keep track of CLOSE messages, 3232 * so we can cleanup the channel. 3233 */ 3234 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3235 return 0; 3236 if ((downstream = c->mux_ctx) == NULL) 3237 return 0; 3238 switch (type) { 3239 case SSH2_MSG_CHANNEL_CLOSE: 3240 case SSH2_MSG_CHANNEL_DATA: 3241 case SSH2_MSG_CHANNEL_EOF: 3242 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3243 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3244 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3245 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3246 case SSH2_MSG_CHANNEL_SUCCESS: 3247 case SSH2_MSG_CHANNEL_FAILURE: 3248 case SSH2_MSG_CHANNEL_REQUEST: 3249 break; 3250 default: 3251 debug2_f("channel %u: unsupported type %u", c->self, type); 3252 return 0; 3253 } 3254 if ((b = sshbuf_new()) == NULL) { 3255 error_f("alloc reply"); 3256 goto out; 3257 } 3258 /* get remaining payload (after id) */ 3259 cp = sshpkt_ptr(ssh, &len); 3260 if (cp == NULL) { 3261 error_f("no packet"); 3262 goto out; 3263 } 3264 /* translate id and send to muxclient */ 3265 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3266 (r = sshbuf_put_u8(b, type)) != 0 || 3267 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3268 (r = sshbuf_put(b, cp, len)) != 0 || 3269 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3270 error_fr(r, "compose muxclient"); 3271 goto out; 3272 } 3273 /* sshbuf_dump(b, stderr); */ 3274 if (ssh_packet_log_type(type)) 3275 debug3_f("channel %u: up->down: type %u", c->self, type); 3276 out: 3277 /* update state */ 3278 switch (type) { 3279 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3280 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3281 if (cp && len > 4) { 3282 c->remote_id = PEEK_U32(cp); 3283 c->have_remote_id = 1; 3284 } 3285 break; 3286 case SSH2_MSG_CHANNEL_CLOSE: 3287 if (c->flags & CHAN_CLOSE_SENT) 3288 channel_free(ssh, c); 3289 else 3290 c->flags |= CHAN_CLOSE_RCVD; 3291 break; 3292 } 3293 sshbuf_free(b); 3294 return 1; 3295 } 3296 3297 /* -- protocol input */ 3298 3299 /* Parse a channel ID from the current packet */ 3300 static int 3301 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3302 { 3303 u_int32_t id; 3304 int r; 3305 3306 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3307 error_r(r, "%s: parse id", where); 3308 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3309 } 3310 if (id > INT_MAX) { 3311 error_r(r, "%s: bad channel id %u", where, id); 3312 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3313 } 3314 return (int)id; 3315 } 3316 3317 /* Lookup a channel from an ID in the current packet */ 3318 static Channel * 3319 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3320 { 3321 int id = channel_parse_id(ssh, where, what); 3322 Channel *c; 3323 3324 if ((c = channel_lookup(ssh, id)) == NULL) { 3325 ssh_packet_disconnect(ssh, 3326 "%s packet referred to nonexistent channel %d", what, id); 3327 } 3328 return c; 3329 } 3330 3331 int 3332 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3333 { 3334 const u_char *data; 3335 size_t data_len, win_len; 3336 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3337 int r; 3338 3339 if (channel_proxy_upstream(c, type, seq, ssh)) 3340 return 0; 3341 3342 /* Ignore any data for non-open channels (might happen on close) */ 3343 if (c->type != SSH_CHANNEL_OPEN && 3344 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3345 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3346 c->type != SSH_CHANNEL_X11_OPEN) 3347 return 0; 3348 3349 /* Get the data. */ 3350 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3351 (r = sshpkt_get_end(ssh)) != 0) 3352 fatal_fr(r, "channel %i: get data", c->self); 3353 3354 win_len = data_len; 3355 if (c->datagram) 3356 win_len += 4; /* string length header */ 3357 3358 /* 3359 * The sending side reduces its window as it sends data, so we 3360 * must 'fake' consumption of the data in order to ensure that window 3361 * updates are sent back. Otherwise the connection might deadlock. 3362 */ 3363 if (c->ostate != CHAN_OUTPUT_OPEN) { 3364 c->local_window -= win_len; 3365 c->local_consumed += win_len; 3366 return 0; 3367 } 3368 3369 if (win_len > c->local_maxpacket) { 3370 logit("channel %d: rcvd big packet %zu, maxpack %u", 3371 c->self, win_len, c->local_maxpacket); 3372 return 0; 3373 } 3374 if (win_len > c->local_window) { 3375 logit("channel %d: rcvd too much data %zu, win %u", 3376 c->self, win_len, c->local_window); 3377 return 0; 3378 } 3379 c->local_window -= win_len; 3380 3381 if (c->datagram) { 3382 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3383 fatal_fr(r, "channel %i: append datagram", c->self); 3384 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3385 fatal_fr(r, "channel %i: append data", c->self); 3386 3387 return 0; 3388 } 3389 3390 int 3391 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3392 { 3393 const u_char *data; 3394 size_t data_len; 3395 u_int32_t tcode; 3396 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3397 int r; 3398 3399 if (channel_proxy_upstream(c, type, seq, ssh)) 3400 return 0; 3401 if (c->type != SSH_CHANNEL_OPEN) { 3402 logit("channel %d: ext data for non open", c->self); 3403 return 0; 3404 } 3405 if (c->flags & CHAN_EOF_RCVD) { 3406 if (ssh->compat & SSH_BUG_EXTEOF) 3407 debug("channel %d: accepting ext data after eof", 3408 c->self); 3409 else 3410 ssh_packet_disconnect(ssh, "Received extended_data " 3411 "after EOF on channel %d.", c->self); 3412 } 3413 3414 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3415 error_fr(r, "parse tcode"); 3416 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3417 } 3418 if (c->efd == -1 || 3419 c->extended_usage != CHAN_EXTENDED_WRITE || 3420 tcode != SSH2_EXTENDED_DATA_STDERR) { 3421 logit("channel %d: bad ext data", c->self); 3422 return 0; 3423 } 3424 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3425 (r = sshpkt_get_end(ssh)) != 0) { 3426 error_fr(r, "parse data"); 3427 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3428 } 3429 3430 if (data_len > c->local_window) { 3431 logit("channel %d: rcvd too much extended_data %zu, win %u", 3432 c->self, data_len, c->local_window); 3433 return 0; 3434 } 3435 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3436 /* XXX sshpkt_getb? */ 3437 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3438 error_fr(r, "append"); 3439 c->local_window -= data_len; 3440 return 0; 3441 } 3442 3443 int 3444 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3445 { 3446 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3447 int r; 3448 3449 if ((r = sshpkt_get_end(ssh)) != 0) { 3450 error_fr(r, "parse data"); 3451 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3452 } 3453 3454 if (channel_proxy_upstream(c, type, seq, ssh)) 3455 return 0; 3456 chan_rcvd_ieof(ssh, c); 3457 3458 /* XXX force input close */ 3459 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3460 debug("channel %d: FORCE input drain", c->self); 3461 c->istate = CHAN_INPUT_WAIT_DRAIN; 3462 if (sshbuf_len(c->input) == 0) 3463 chan_ibuf_empty(ssh, c); 3464 } 3465 return 0; 3466 } 3467 3468 int 3469 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3470 { 3471 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3472 int r; 3473 3474 if (channel_proxy_upstream(c, type, seq, ssh)) 3475 return 0; 3476 if ((r = sshpkt_get_end(ssh)) != 0) { 3477 error_fr(r, "parse data"); 3478 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3479 } 3480 chan_rcvd_oclose(ssh, c); 3481 return 0; 3482 } 3483 3484 int 3485 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3486 { 3487 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3488 u_int32_t remote_window, remote_maxpacket; 3489 int r; 3490 3491 if (channel_proxy_upstream(c, type, seq, ssh)) 3492 return 0; 3493 if (c->type != SSH_CHANNEL_OPENING) 3494 ssh_packet_disconnect(ssh, "Received open confirmation for " 3495 "non-opening channel %d.", c->self); 3496 /* 3497 * Record the remote channel number and mark that the channel 3498 * is now open. 3499 */ 3500 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3501 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3502 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3503 (r = sshpkt_get_end(ssh)) != 0) { 3504 error_fr(r, "window/maxpacket"); 3505 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3506 } 3507 3508 c->have_remote_id = 1; 3509 c->remote_window = remote_window; 3510 c->remote_maxpacket = remote_maxpacket; 3511 c->type = SSH_CHANNEL_OPEN; 3512 if (c->open_confirm) { 3513 debug2_f("channel %d: callback start", c->self); 3514 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3515 debug2_f("channel %d: callback done", c->self); 3516 } 3517 c->lastused = monotime(); 3518 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3519 c->remote_window, c->remote_maxpacket); 3520 return 0; 3521 } 3522 3523 static char * 3524 reason2txt(int reason) 3525 { 3526 switch (reason) { 3527 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3528 return "administratively prohibited"; 3529 case SSH2_OPEN_CONNECT_FAILED: 3530 return "connect failed"; 3531 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3532 return "unknown channel type"; 3533 case SSH2_OPEN_RESOURCE_SHORTAGE: 3534 return "resource shortage"; 3535 } 3536 return "unknown reason"; 3537 } 3538 3539 int 3540 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3541 { 3542 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3543 u_int32_t reason; 3544 char *msg = NULL; 3545 int r; 3546 3547 if (channel_proxy_upstream(c, type, seq, ssh)) 3548 return 0; 3549 if (c->type != SSH_CHANNEL_OPENING) 3550 ssh_packet_disconnect(ssh, "Received open failure for " 3551 "non-opening channel %d.", c->self); 3552 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3553 error_fr(r, "parse reason"); 3554 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3555 } 3556 /* skip language */ 3557 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3558 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3559 (r = sshpkt_get_end(ssh)) != 0) { 3560 error_fr(r, "parse msg/lang"); 3561 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3562 } 3563 logit("channel %d: open failed: %s%s%s", c->self, 3564 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3565 free(msg); 3566 if (c->open_confirm) { 3567 debug2_f("channel %d: callback start", c->self); 3568 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3569 debug2_f("channel %d: callback done", c->self); 3570 } 3571 /* Schedule the channel for cleanup/deletion. */ 3572 chan_mark_dead(ssh, c); 3573 return 0; 3574 } 3575 3576 int 3577 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3578 { 3579 int id = channel_parse_id(ssh, __func__, "window adjust"); 3580 Channel *c; 3581 u_int32_t adjust; 3582 u_int new_rwin; 3583 int r; 3584 3585 if ((c = channel_lookup(ssh, id)) == NULL) { 3586 logit("Received window adjust for non-open channel %d.", id); 3587 return 0; 3588 } 3589 3590 if (channel_proxy_upstream(c, type, seq, ssh)) 3591 return 0; 3592 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3593 (r = sshpkt_get_end(ssh)) != 0) { 3594 error_fr(r, "parse adjust"); 3595 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3596 } 3597 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3598 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3599 fatal("channel %d: adjust %u overflows remote window %u", 3600 c->self, adjust, c->remote_window); 3601 } 3602 c->remote_window = new_rwin; 3603 return 0; 3604 } 3605 3606 int 3607 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3608 { 3609 int id = channel_parse_id(ssh, __func__, "status confirm"); 3610 Channel *c; 3611 struct channel_confirm *cc; 3612 3613 /* Reset keepalive timeout */ 3614 ssh_packet_set_alive_timeouts(ssh, 0); 3615 3616 debug2_f("type %d id %d", type, id); 3617 3618 if ((c = channel_lookup(ssh, id)) == NULL) { 3619 logit_f("%d: unknown", id); 3620 return 0; 3621 } 3622 if (channel_proxy_upstream(c, type, seq, ssh)) 3623 return 0; 3624 if (sshpkt_get_end(ssh) != 0) 3625 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3626 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3627 return 0; 3628 cc->cb(ssh, type, c, cc->ctx); 3629 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3630 freezero(cc, sizeof(*cc)); 3631 return 0; 3632 } 3633 3634 /* -- tcp forwarding */ 3635 3636 void 3637 channel_set_af(struct ssh *ssh, int af) 3638 { 3639 ssh->chanctxt->IPv4or6 = af; 3640 } 3641 3642 3643 /* 3644 * Determine whether or not a port forward listens to loopback, the 3645 * specified address or wildcard. On the client, a specified bind 3646 * address will always override gateway_ports. On the server, a 3647 * gateway_ports of 1 (``yes'') will override the client's specification 3648 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3649 * will bind to whatever address the client asked for. 3650 * 3651 * Special-case listen_addrs are: 3652 * 3653 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3654 * "" (empty string), "*" -> wildcard v4/v6 3655 * "localhost" -> loopback v4/v6 3656 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3657 */ 3658 static const char * 3659 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3660 int is_client, struct ForwardOptions *fwd_opts) 3661 { 3662 const char *addr = NULL; 3663 int wildcard = 0; 3664 3665 if (listen_addr == NULL) { 3666 /* No address specified: default to gateway_ports setting */ 3667 if (fwd_opts->gateway_ports) 3668 wildcard = 1; 3669 } else if (fwd_opts->gateway_ports || is_client) { 3670 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3671 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3672 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3673 (!is_client && fwd_opts->gateway_ports == 1)) { 3674 wildcard = 1; 3675 /* 3676 * Notify client if they requested a specific listen 3677 * address and it was overridden. 3678 */ 3679 if (*listen_addr != '\0' && 3680 strcmp(listen_addr, "0.0.0.0") != 0 && 3681 strcmp(listen_addr, "*") != 0) { 3682 ssh_packet_send_debug(ssh, 3683 "Forwarding listen address " 3684 "\"%s\" overridden by server " 3685 "GatewayPorts", listen_addr); 3686 } 3687 } else if (strcmp(listen_addr, "localhost") != 0 || 3688 strcmp(listen_addr, "127.0.0.1") == 0 || 3689 strcmp(listen_addr, "::1") == 0) { 3690 /* 3691 * Accept explicit localhost address when 3692 * GatewayPorts=yes. The "localhost" hostname is 3693 * deliberately skipped here so it will listen on all 3694 * available local address families. 3695 */ 3696 addr = listen_addr; 3697 } 3698 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3699 strcmp(listen_addr, "::1") == 0) { 3700 /* 3701 * If a specific IPv4/IPv6 localhost address has been 3702 * requested then accept it even if gateway_ports is in 3703 * effect. This allows the client to prefer IPv4 or IPv6. 3704 */ 3705 addr = listen_addr; 3706 } 3707 if (wildcardp != NULL) 3708 *wildcardp = wildcard; 3709 return addr; 3710 } 3711 3712 static int 3713 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3714 struct Forward *fwd, int *allocated_listen_port, 3715 struct ForwardOptions *fwd_opts) 3716 { 3717 Channel *c; 3718 int sock, r, success = 0, wildcard = 0, is_client; 3719 struct addrinfo hints, *ai, *aitop; 3720 const char *host, *addr; 3721 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3722 in_port_t *lport_p; 3723 3724 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3725 3726 if (is_client && fwd->connect_path != NULL) { 3727 host = fwd->connect_path; 3728 } else { 3729 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3730 fwd->listen_host : fwd->connect_host; 3731 if (host == NULL) { 3732 error("No forward host name."); 3733 return 0; 3734 } 3735 if (strlen(host) >= NI_MAXHOST) { 3736 error("Forward host name too long."); 3737 return 0; 3738 } 3739 } 3740 3741 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3742 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3743 is_client, fwd_opts); 3744 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3745 (addr == NULL) ? "NULL" : addr); 3746 3747 /* 3748 * getaddrinfo returns a loopback address if the hostname is 3749 * set to NULL and hints.ai_flags is not AI_PASSIVE 3750 */ 3751 memset(&hints, 0, sizeof(hints)); 3752 hints.ai_family = ssh->chanctxt->IPv4or6; 3753 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3754 hints.ai_socktype = SOCK_STREAM; 3755 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3756 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3757 if (addr == NULL) { 3758 /* This really shouldn't happen */ 3759 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3760 ssh_gai_strerror(r)); 3761 } else { 3762 error_f("getaddrinfo(%.64s): %s", addr, 3763 ssh_gai_strerror(r)); 3764 } 3765 return 0; 3766 } 3767 if (allocated_listen_port != NULL) 3768 *allocated_listen_port = 0; 3769 for (ai = aitop; ai; ai = ai->ai_next) { 3770 switch (ai->ai_family) { 3771 case AF_INET: 3772 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3773 sin_port; 3774 break; 3775 case AF_INET6: 3776 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3777 sin6_port; 3778 break; 3779 default: 3780 continue; 3781 } 3782 /* 3783 * If allocating a port for -R forwards, then use the 3784 * same port for all address families. 3785 */ 3786 if (type == SSH_CHANNEL_RPORT_LISTENER && 3787 fwd->listen_port == 0 && allocated_listen_port != NULL && 3788 *allocated_listen_port > 0) 3789 *lport_p = htons(*allocated_listen_port); 3790 3791 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3792 strport, sizeof(strport), 3793 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3794 error_f("getnameinfo failed"); 3795 continue; 3796 } 3797 /* Create a port to listen for the host. */ 3798 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3799 if (sock == -1) { 3800 /* this is no error since kernel may not support ipv6 */ 3801 verbose("socket [%s]:%s: %.100s", ntop, strport, 3802 strerror(errno)); 3803 continue; 3804 } 3805 3806 set_reuseaddr(sock); 3807 if (ai->ai_family == AF_INET6) 3808 sock_set_v6only(sock); 3809 3810 debug("Local forwarding listening on %s port %s.", 3811 ntop, strport); 3812 3813 /* Bind the socket to the address. */ 3814 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3815 /* 3816 * address can be in if use ipv6 address is 3817 * already bound 3818 */ 3819 if (!ai->ai_next) 3820 error("bind [%s]:%s: %.100s", 3821 ntop, strport, strerror(errno)); 3822 else 3823 verbose("bind [%s]:%s: %.100s", 3824 ntop, strport, strerror(errno)); 3825 3826 close(sock); 3827 continue; 3828 } 3829 /* Start listening for connections on the socket. */ 3830 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3831 error("listen [%s]:%s: %.100s", ntop, strport, 3832 strerror(errno)); 3833 close(sock); 3834 continue; 3835 } 3836 3837 /* 3838 * fwd->listen_port == 0 requests a dynamically allocated port - 3839 * record what we got. 3840 */ 3841 if (type == SSH_CHANNEL_RPORT_LISTENER && 3842 fwd->listen_port == 0 && 3843 allocated_listen_port != NULL && 3844 *allocated_listen_port == 0) { 3845 *allocated_listen_port = get_local_port(sock); 3846 debug("Allocated listen port %d", 3847 *allocated_listen_port); 3848 } 3849 3850 /* Allocate a channel number for the socket. */ 3851 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3852 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3853 0, "port listener", 1); 3854 c->path = xstrdup(host); 3855 c->host_port = fwd->connect_port; 3856 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3857 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3858 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3859 c->listening_port = *allocated_listen_port; 3860 else 3861 c->listening_port = fwd->listen_port; 3862 success = 1; 3863 } 3864 if (success == 0) 3865 error_f("cannot listen to port: %d", fwd->listen_port); 3866 freeaddrinfo(aitop); 3867 return success; 3868 } 3869 3870 static int 3871 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3872 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3873 { 3874 struct sockaddr_un sunaddr; 3875 const char *path; 3876 Channel *c; 3877 int port, sock; 3878 mode_t omask; 3879 3880 switch (type) { 3881 case SSH_CHANNEL_UNIX_LISTENER: 3882 if (fwd->connect_path != NULL) { 3883 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3884 error("Local connecting path too long: %s", 3885 fwd->connect_path); 3886 return 0; 3887 } 3888 path = fwd->connect_path; 3889 port = PORT_STREAMLOCAL; 3890 } else { 3891 if (fwd->connect_host == NULL) { 3892 error("No forward host name."); 3893 return 0; 3894 } 3895 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3896 error("Forward host name too long."); 3897 return 0; 3898 } 3899 path = fwd->connect_host; 3900 port = fwd->connect_port; 3901 } 3902 break; 3903 case SSH_CHANNEL_RUNIX_LISTENER: 3904 path = fwd->listen_path; 3905 port = PORT_STREAMLOCAL; 3906 break; 3907 default: 3908 error_f("unexpected channel type %d", type); 3909 return 0; 3910 } 3911 3912 if (fwd->listen_path == NULL) { 3913 error("No forward path name."); 3914 return 0; 3915 } 3916 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3917 error("Local listening path too long: %s", fwd->listen_path); 3918 return 0; 3919 } 3920 3921 debug3_f("type %d path %s", type, fwd->listen_path); 3922 3923 /* Start a Unix domain listener. */ 3924 omask = umask(fwd_opts->streamlocal_bind_mask); 3925 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3926 fwd_opts->streamlocal_bind_unlink); 3927 umask(omask); 3928 if (sock < 0) 3929 return 0; 3930 3931 debug("Local forwarding listening on path %s.", fwd->listen_path); 3932 3933 /* Allocate a channel number for the socket. */ 3934 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 3935 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3936 0, "unix listener", 1); 3937 c->path = xstrdup(path); 3938 c->host_port = port; 3939 c->listening_port = PORT_STREAMLOCAL; 3940 c->listening_addr = xstrdup(fwd->listen_path); 3941 return 1; 3942 } 3943 3944 static int 3945 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3946 const char *host, u_short port) 3947 { 3948 u_int i; 3949 int found = 0; 3950 3951 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3952 Channel *c = ssh->chanctxt->channels[i]; 3953 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3954 continue; 3955 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3956 debug2_f("close channel %d", i); 3957 channel_free(ssh, c); 3958 found = 1; 3959 } 3960 } 3961 3962 return found; 3963 } 3964 3965 static int 3966 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3967 { 3968 u_int i; 3969 int found = 0; 3970 3971 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3972 Channel *c = ssh->chanctxt->channels[i]; 3973 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3974 continue; 3975 if (c->path == NULL) 3976 continue; 3977 if (strcmp(c->path, path) == 0) { 3978 debug2_f("close channel %d", i); 3979 channel_free(ssh, c); 3980 found = 1; 3981 } 3982 } 3983 3984 return found; 3985 } 3986 3987 int 3988 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3989 { 3990 if (fwd->listen_path != NULL) { 3991 return channel_cancel_rport_listener_streamlocal(ssh, 3992 fwd->listen_path); 3993 } else { 3994 return channel_cancel_rport_listener_tcpip(ssh, 3995 fwd->listen_host, fwd->listen_port); 3996 } 3997 } 3998 3999 static int 4000 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4001 const char *lhost, u_short lport, int cport, 4002 struct ForwardOptions *fwd_opts) 4003 { 4004 u_int i; 4005 int found = 0; 4006 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4007 4008 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4009 Channel *c = ssh->chanctxt->channels[i]; 4010 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4011 continue; 4012 if (c->listening_port != lport) 4013 continue; 4014 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4015 /* skip dynamic forwardings */ 4016 if (c->host_port == 0) 4017 continue; 4018 } else { 4019 if (c->host_port != cport) 4020 continue; 4021 } 4022 if ((c->listening_addr == NULL && addr != NULL) || 4023 (c->listening_addr != NULL && addr == NULL)) 4024 continue; 4025 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4026 debug2_f("close channel %d", i); 4027 channel_free(ssh, c); 4028 found = 1; 4029 } 4030 } 4031 4032 return found; 4033 } 4034 4035 static int 4036 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4037 { 4038 u_int i; 4039 int found = 0; 4040 4041 if (path == NULL) { 4042 error_f("no path specified."); 4043 return 0; 4044 } 4045 4046 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4047 Channel *c = ssh->chanctxt->channels[i]; 4048 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4049 continue; 4050 if (c->listening_addr == NULL) 4051 continue; 4052 if (strcmp(c->listening_addr, path) == 0) { 4053 debug2_f("close channel %d", i); 4054 channel_free(ssh, c); 4055 found = 1; 4056 } 4057 } 4058 4059 return found; 4060 } 4061 4062 int 4063 channel_cancel_lport_listener(struct ssh *ssh, 4064 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4065 { 4066 if (fwd->listen_path != NULL) { 4067 return channel_cancel_lport_listener_streamlocal(ssh, 4068 fwd->listen_path); 4069 } else { 4070 return channel_cancel_lport_listener_tcpip(ssh, 4071 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4072 } 4073 } 4074 4075 /* protocol local port fwd, used by ssh */ 4076 int 4077 channel_setup_local_fwd_listener(struct ssh *ssh, 4078 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4079 { 4080 if (fwd->listen_path != NULL) { 4081 return channel_setup_fwd_listener_streamlocal(ssh, 4082 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4083 } else { 4084 return channel_setup_fwd_listener_tcpip(ssh, 4085 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4086 } 4087 } 4088 4089 /* Matches a remote forwarding permission against a requested forwarding */ 4090 static int 4091 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4092 { 4093 int ret; 4094 char *lhost; 4095 4096 /* XXX add ACLs for streamlocal */ 4097 if (fwd->listen_path != NULL) 4098 return 1; 4099 4100 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4101 return 0; 4102 4103 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4104 allowed_open->listen_port != fwd->listen_port) 4105 return 0; 4106 4107 /* Match hostnames case-insensitively */ 4108 lhost = xstrdup(fwd->listen_host); 4109 lowercase(lhost); 4110 ret = match_pattern(lhost, allowed_open->listen_host); 4111 free(lhost); 4112 4113 return ret; 4114 } 4115 4116 /* Checks whether a requested remote forwarding is permitted */ 4117 static int 4118 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4119 { 4120 struct ssh_channels *sc = ssh->chanctxt; 4121 struct permission_set *pset = &sc->remote_perms; 4122 u_int i, permit, permit_adm = 1; 4123 struct permission *perm; 4124 4125 /* XXX apply GatewayPorts override before checking? */ 4126 4127 permit = pset->all_permitted; 4128 if (!permit) { 4129 for (i = 0; i < pset->num_permitted_user; i++) { 4130 perm = &pset->permitted_user[i]; 4131 if (remote_open_match(perm, fwd)) { 4132 permit = 1; 4133 break; 4134 } 4135 } 4136 } 4137 4138 if (pset->num_permitted_admin > 0) { 4139 permit_adm = 0; 4140 for (i = 0; i < pset->num_permitted_admin; i++) { 4141 perm = &pset->permitted_admin[i]; 4142 if (remote_open_match(perm, fwd)) { 4143 permit_adm = 1; 4144 break; 4145 } 4146 } 4147 } 4148 4149 return permit && permit_adm; 4150 } 4151 4152 /* protocol v2 remote port fwd, used by sshd */ 4153 int 4154 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4155 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4156 { 4157 if (!check_rfwd_permission(ssh, fwd)) { 4158 ssh_packet_send_debug(ssh, "port forwarding refused"); 4159 if (fwd->listen_path != NULL) 4160 /* XXX always allowed, see remote_open_match() */ 4161 logit("Received request from %.100s port %d to " 4162 "remote forward to path \"%.100s\", " 4163 "but the request was denied.", 4164 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4165 fwd->listen_path); 4166 else if(fwd->listen_host != NULL) 4167 logit("Received request from %.100s port %d to " 4168 "remote forward to host %.100s port %d, " 4169 "but the request was denied.", 4170 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4171 fwd->listen_host, fwd->listen_port ); 4172 else 4173 logit("Received request from %.100s port %d to remote " 4174 "forward, but the request was denied.", 4175 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4176 return 0; 4177 } 4178 if (fwd->listen_path != NULL) { 4179 return channel_setup_fwd_listener_streamlocal(ssh, 4180 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4181 } else { 4182 return channel_setup_fwd_listener_tcpip(ssh, 4183 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4184 fwd_opts); 4185 } 4186 } 4187 4188 /* 4189 * Translate the requested rfwd listen host to something usable for 4190 * this server. 4191 */ 4192 static const char * 4193 channel_rfwd_bind_host(const char *listen_host) 4194 { 4195 if (listen_host == NULL) { 4196 return "localhost"; 4197 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4198 return ""; 4199 } else 4200 return listen_host; 4201 } 4202 4203 /* 4204 * Initiate forwarding of connections to port "port" on remote host through 4205 * the secure channel to host:port from local side. 4206 * Returns handle (index) for updating the dynamic listen port with 4207 * channel_update_permission(). 4208 */ 4209 int 4210 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4211 { 4212 int r, success = 0, idx = -1; 4213 const char *host_to_connect, *listen_host, *listen_path; 4214 int port_to_connect, listen_port; 4215 4216 /* Send the forward request to the remote side. */ 4217 if (fwd->listen_path != NULL) { 4218 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4219 (r = sshpkt_put_cstring(ssh, 4220 "streamlocal-forward@openssh.com")) != 0 || 4221 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4222 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4223 (r = sshpkt_send(ssh)) != 0 || 4224 (r = ssh_packet_write_wait(ssh)) != 0) 4225 fatal_fr(r, "request streamlocal"); 4226 } else { 4227 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4228 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4229 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4230 (r = sshpkt_put_cstring(ssh, 4231 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4232 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4233 (r = sshpkt_send(ssh)) != 0 || 4234 (r = ssh_packet_write_wait(ssh)) != 0) 4235 fatal_fr(r, "request tcpip-forward"); 4236 } 4237 /* Assume that server accepts the request */ 4238 success = 1; 4239 if (success) { 4240 /* Record that connection to this host/port is permitted. */ 4241 host_to_connect = listen_host = listen_path = NULL; 4242 port_to_connect = listen_port = 0; 4243 if (fwd->connect_path != NULL) { 4244 host_to_connect = fwd->connect_path; 4245 port_to_connect = PORT_STREAMLOCAL; 4246 } else { 4247 host_to_connect = fwd->connect_host; 4248 port_to_connect = fwd->connect_port; 4249 } 4250 if (fwd->listen_path != NULL) { 4251 listen_path = fwd->listen_path; 4252 listen_port = PORT_STREAMLOCAL; 4253 } else { 4254 listen_host = fwd->listen_host; 4255 listen_port = fwd->listen_port; 4256 } 4257 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4258 host_to_connect, port_to_connect, 4259 listen_host, listen_path, listen_port, NULL); 4260 } 4261 return idx; 4262 } 4263 4264 static int 4265 open_match(struct permission *allowed_open, const char *requestedhost, 4266 int requestedport) 4267 { 4268 if (allowed_open->host_to_connect == NULL) 4269 return 0; 4270 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4271 allowed_open->port_to_connect != requestedport) 4272 return 0; 4273 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4274 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4275 return 0; 4276 return 1; 4277 } 4278 4279 /* 4280 * Note that in the listen host/port case 4281 * we don't support FWD_PERMIT_ANY_PORT and 4282 * need to translate between the configured-host (listen_host) 4283 * and what we've sent to the remote server (channel_rfwd_bind_host) 4284 */ 4285 static int 4286 open_listen_match_tcpip(struct permission *allowed_open, 4287 const char *requestedhost, u_short requestedport, int translate) 4288 { 4289 const char *allowed_host; 4290 4291 if (allowed_open->host_to_connect == NULL) 4292 return 0; 4293 if (allowed_open->listen_port != requestedport) 4294 return 0; 4295 if (!translate && allowed_open->listen_host == NULL && 4296 requestedhost == NULL) 4297 return 1; 4298 allowed_host = translate ? 4299 channel_rfwd_bind_host(allowed_open->listen_host) : 4300 allowed_open->listen_host; 4301 if (allowed_host == NULL || requestedhost == NULL || 4302 strcmp(allowed_host, requestedhost) != 0) 4303 return 0; 4304 return 1; 4305 } 4306 4307 static int 4308 open_listen_match_streamlocal(struct permission *allowed_open, 4309 const char *requestedpath) 4310 { 4311 if (allowed_open->host_to_connect == NULL) 4312 return 0; 4313 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4314 return 0; 4315 if (allowed_open->listen_path == NULL || 4316 strcmp(allowed_open->listen_path, requestedpath) != 0) 4317 return 0; 4318 return 1; 4319 } 4320 4321 /* 4322 * Request cancellation of remote forwarding of connection host:port from 4323 * local side. 4324 */ 4325 static int 4326 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4327 const char *host, u_short port) 4328 { 4329 struct ssh_channels *sc = ssh->chanctxt; 4330 struct permission_set *pset = &sc->local_perms; 4331 int r; 4332 u_int i; 4333 struct permission *perm = NULL; 4334 4335 for (i = 0; i < pset->num_permitted_user; i++) { 4336 perm = &pset->permitted_user[i]; 4337 if (open_listen_match_tcpip(perm, host, port, 0)) 4338 break; 4339 perm = NULL; 4340 } 4341 if (perm == NULL) { 4342 debug_f("requested forward not found"); 4343 return -1; 4344 } 4345 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4346 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4347 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4348 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4349 (r = sshpkt_put_u32(ssh, port)) != 0 || 4350 (r = sshpkt_send(ssh)) != 0) 4351 fatal_fr(r, "send cancel"); 4352 4353 fwd_perm_clear(perm); /* unregister */ 4354 4355 return 0; 4356 } 4357 4358 /* 4359 * Request cancellation of remote forwarding of Unix domain socket 4360 * path from local side. 4361 */ 4362 static int 4363 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4364 { 4365 struct ssh_channels *sc = ssh->chanctxt; 4366 struct permission_set *pset = &sc->local_perms; 4367 int r; 4368 u_int i; 4369 struct permission *perm = NULL; 4370 4371 for (i = 0; i < pset->num_permitted_user; i++) { 4372 perm = &pset->permitted_user[i]; 4373 if (open_listen_match_streamlocal(perm, path)) 4374 break; 4375 perm = NULL; 4376 } 4377 if (perm == NULL) { 4378 debug_f("requested forward not found"); 4379 return -1; 4380 } 4381 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4382 (r = sshpkt_put_cstring(ssh, 4383 "cancel-streamlocal-forward@openssh.com")) != 0 || 4384 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4385 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4386 (r = sshpkt_send(ssh)) != 0) 4387 fatal_fr(r, "send cancel"); 4388 4389 fwd_perm_clear(perm); /* unregister */ 4390 4391 return 0; 4392 } 4393 4394 /* 4395 * Request cancellation of remote forwarding of a connection from local side. 4396 */ 4397 int 4398 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4399 { 4400 if (fwd->listen_path != NULL) { 4401 return channel_request_rforward_cancel_streamlocal(ssh, 4402 fwd->listen_path); 4403 } else { 4404 return channel_request_rforward_cancel_tcpip(ssh, 4405 fwd->listen_host, 4406 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4407 } 4408 } 4409 4410 /* 4411 * Permits opening to any host/port if permitted_user[] is empty. This is 4412 * usually called by the server, because the user could connect to any port 4413 * anyway, and the server has no way to know but to trust the client anyway. 4414 */ 4415 void 4416 channel_permit_all(struct ssh *ssh, int where) 4417 { 4418 struct permission_set *pset = permission_set_get(ssh, where); 4419 4420 if (pset->num_permitted_user == 0) 4421 pset->all_permitted = 1; 4422 } 4423 4424 /* 4425 * Permit the specified host/port for forwarding. 4426 */ 4427 void 4428 channel_add_permission(struct ssh *ssh, int who, int where, 4429 char *host, int port) 4430 { 4431 int local = where == FORWARD_LOCAL; 4432 struct permission_set *pset = permission_set_get(ssh, where); 4433 4434 debug("allow %s forwarding to host %s port %d", 4435 fwd_ident(who, where), host, port); 4436 /* 4437 * Remote forwards set listen_host/port, local forwards set 4438 * host/port_to_connect. 4439 */ 4440 permission_set_add(ssh, who, where, 4441 local ? host : 0, local ? port : 0, 4442 local ? NULL : host, NULL, local ? 0 : port, NULL); 4443 pset->all_permitted = 0; 4444 } 4445 4446 /* 4447 * Administratively disable forwarding. 4448 */ 4449 void 4450 channel_disable_admin(struct ssh *ssh, int where) 4451 { 4452 channel_clear_permission(ssh, FORWARD_ADM, where); 4453 permission_set_add(ssh, FORWARD_ADM, where, 4454 NULL, 0, NULL, NULL, 0, NULL); 4455 } 4456 4457 /* 4458 * Clear a list of permitted opens. 4459 */ 4460 void 4461 channel_clear_permission(struct ssh *ssh, int who, int where) 4462 { 4463 struct permission **permp; 4464 u_int *npermp; 4465 4466 permission_set_get_array(ssh, who, where, &permp, &npermp); 4467 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4468 *npermp = 0; 4469 } 4470 4471 /* 4472 * Update the listen port for a dynamic remote forward, after 4473 * the actual 'newport' has been allocated. If 'newport' < 0 is 4474 * passed then they entry will be invalidated. 4475 */ 4476 void 4477 channel_update_permission(struct ssh *ssh, int idx, int newport) 4478 { 4479 struct permission_set *pset = &ssh->chanctxt->local_perms; 4480 4481 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4482 debug_f("index out of range: %d num_permitted_user %d", 4483 idx, pset->num_permitted_user); 4484 return; 4485 } 4486 debug("%s allowed port %d for forwarding to host %s port %d", 4487 newport > 0 ? "Updating" : "Removing", 4488 newport, 4489 pset->permitted_user[idx].host_to_connect, 4490 pset->permitted_user[idx].port_to_connect); 4491 if (newport <= 0) 4492 fwd_perm_clear(&pset->permitted_user[idx]); 4493 else { 4494 pset->permitted_user[idx].listen_port = 4495 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4496 } 4497 } 4498 4499 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4500 int 4501 permitopen_port(const char *p) 4502 { 4503 int port; 4504 4505 if (strcmp(p, "*") == 0) 4506 return FWD_PERMIT_ANY_PORT; 4507 if ((port = a2port(p)) > 0) 4508 return port; 4509 return -1; 4510 } 4511 4512 /* Try to start non-blocking connect to next host in cctx list */ 4513 static int 4514 connect_next(struct channel_connect *cctx) 4515 { 4516 int sock, saved_errno; 4517 struct sockaddr_un *sunaddr; 4518 char ntop[NI_MAXHOST]; 4519 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4520 4521 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4522 switch (cctx->ai->ai_family) { 4523 case AF_UNIX: 4524 /* unix:pathname instead of host:port */ 4525 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4526 strlcpy(ntop, "unix", sizeof(ntop)); 4527 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4528 break; 4529 case AF_INET: 4530 case AF_INET6: 4531 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4532 ntop, sizeof(ntop), strport, sizeof(strport), 4533 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4534 error_f("getnameinfo failed"); 4535 continue; 4536 } 4537 break; 4538 default: 4539 continue; 4540 } 4541 debug_f("start for host %.100s ([%.100s]:%s)", 4542 cctx->host, ntop, strport); 4543 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4544 cctx->ai->ai_protocol)) == -1) { 4545 if (cctx->ai->ai_next == NULL) 4546 error("socket: %.100s", strerror(errno)); 4547 else 4548 verbose("socket: %.100s", strerror(errno)); 4549 continue; 4550 } 4551 if (set_nonblock(sock) == -1) 4552 fatal_f("set_nonblock(%d)", sock); 4553 if (connect(sock, cctx->ai->ai_addr, 4554 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4555 debug_f("host %.100s ([%.100s]:%s): %.100s", 4556 cctx->host, ntop, strport, strerror(errno)); 4557 saved_errno = errno; 4558 close(sock); 4559 errno = saved_errno; 4560 continue; /* fail -- try next */ 4561 } 4562 if (cctx->ai->ai_family != AF_UNIX) 4563 set_nodelay(sock); 4564 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4565 cctx->host, ntop, strport, sock); 4566 cctx->ai = cctx->ai->ai_next; 4567 return sock; 4568 } 4569 return -1; 4570 } 4571 4572 static void 4573 channel_connect_ctx_free(struct channel_connect *cctx) 4574 { 4575 free(cctx->host); 4576 if (cctx->aitop) { 4577 if (cctx->aitop->ai_family == AF_UNIX) 4578 free(cctx->aitop); 4579 else 4580 freeaddrinfo(cctx->aitop); 4581 } 4582 memset(cctx, 0, sizeof(*cctx)); 4583 } 4584 4585 /* 4586 * Return connecting socket to remote host:port or local socket path, 4587 * passing back the failure reason if appropriate. 4588 */ 4589 static int 4590 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4591 char *ctype, char *rname, struct channel_connect *cctx, 4592 int *reason, const char **errmsg) 4593 { 4594 struct addrinfo hints; 4595 int gaierr; 4596 int sock = -1; 4597 char strport[NI_MAXSERV]; 4598 4599 if (port == PORT_STREAMLOCAL) { 4600 struct sockaddr_un *sunaddr; 4601 struct addrinfo *ai; 4602 4603 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4604 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4605 return -1; 4606 } 4607 4608 /* 4609 * Fake up a struct addrinfo for AF_UNIX connections. 4610 * channel_connect_ctx_free() must check ai_family 4611 * and use free() not freeaddirinfo() for AF_UNIX. 4612 */ 4613 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4614 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4615 ai->ai_addr = (struct sockaddr *)(ai + 1); 4616 ai->ai_addrlen = sizeof(*sunaddr); 4617 ai->ai_family = AF_UNIX; 4618 ai->ai_socktype = socktype; 4619 ai->ai_protocol = PF_UNSPEC; 4620 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4621 sunaddr->sun_family = AF_UNIX; 4622 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4623 cctx->aitop = ai; 4624 } else { 4625 memset(&hints, 0, sizeof(hints)); 4626 hints.ai_family = ssh->chanctxt->IPv4or6; 4627 hints.ai_socktype = socktype; 4628 snprintf(strport, sizeof strport, "%d", port); 4629 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4630 != 0) { 4631 if (errmsg != NULL) 4632 *errmsg = ssh_gai_strerror(gaierr); 4633 if (reason != NULL) 4634 *reason = SSH2_OPEN_CONNECT_FAILED; 4635 error("connect_to %.100s: unknown host (%s)", name, 4636 ssh_gai_strerror(gaierr)); 4637 return -1; 4638 } 4639 } 4640 4641 cctx->host = xstrdup(name); 4642 cctx->port = port; 4643 cctx->ai = cctx->aitop; 4644 4645 if ((sock = connect_next(cctx)) == -1) { 4646 error("connect to %.100s port %d failed: %s", 4647 name, port, strerror(errno)); 4648 return -1; 4649 } 4650 4651 return sock; 4652 } 4653 4654 /* Return CONNECTING channel to remote host:port or local socket path */ 4655 static Channel * 4656 connect_to(struct ssh *ssh, const char *host, int port, 4657 char *ctype, char *rname) 4658 { 4659 struct channel_connect cctx; 4660 Channel *c; 4661 int sock; 4662 4663 memset(&cctx, 0, sizeof(cctx)); 4664 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4665 &cctx, NULL, NULL); 4666 if (sock == -1) { 4667 channel_connect_ctx_free(&cctx); 4668 return NULL; 4669 } 4670 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4671 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4672 c->host_port = port; 4673 c->path = xstrdup(host); 4674 c->connect_ctx = cctx; 4675 4676 return c; 4677 } 4678 4679 /* 4680 * returns either the newly connected channel or the downstream channel 4681 * that needs to deal with this connection. 4682 */ 4683 Channel * 4684 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4685 u_short listen_port, char *ctype, char *rname) 4686 { 4687 struct ssh_channels *sc = ssh->chanctxt; 4688 struct permission_set *pset = &sc->local_perms; 4689 u_int i; 4690 struct permission *perm; 4691 4692 for (i = 0; i < pset->num_permitted_user; i++) { 4693 perm = &pset->permitted_user[i]; 4694 if (open_listen_match_tcpip(perm, 4695 listen_host, listen_port, 1)) { 4696 if (perm->downstream) 4697 return perm->downstream; 4698 if (perm->port_to_connect == 0) 4699 return rdynamic_connect_prepare(ssh, 4700 ctype, rname); 4701 return connect_to(ssh, 4702 perm->host_to_connect, perm->port_to_connect, 4703 ctype, rname); 4704 } 4705 } 4706 error("WARNING: Server requests forwarding for unknown listen_port %d", 4707 listen_port); 4708 return NULL; 4709 } 4710 4711 Channel * 4712 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4713 char *ctype, char *rname) 4714 { 4715 struct ssh_channels *sc = ssh->chanctxt; 4716 struct permission_set *pset = &sc->local_perms; 4717 u_int i; 4718 struct permission *perm; 4719 4720 for (i = 0; i < pset->num_permitted_user; i++) { 4721 perm = &pset->permitted_user[i]; 4722 if (open_listen_match_streamlocal(perm, path)) { 4723 return connect_to(ssh, 4724 perm->host_to_connect, perm->port_to_connect, 4725 ctype, rname); 4726 } 4727 } 4728 error("WARNING: Server requests forwarding for unknown path %.100s", 4729 path); 4730 return NULL; 4731 } 4732 4733 /* Check if connecting to that port is permitted and connect. */ 4734 Channel * 4735 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4736 char *ctype, char *rname, int *reason, const char **errmsg) 4737 { 4738 struct ssh_channels *sc = ssh->chanctxt; 4739 struct permission_set *pset = &sc->local_perms; 4740 struct channel_connect cctx; 4741 Channel *c; 4742 u_int i, permit, permit_adm = 1; 4743 int sock; 4744 struct permission *perm; 4745 4746 permit = pset->all_permitted; 4747 if (!permit) { 4748 for (i = 0; i < pset->num_permitted_user; i++) { 4749 perm = &pset->permitted_user[i]; 4750 if (open_match(perm, host, port)) { 4751 permit = 1; 4752 break; 4753 } 4754 } 4755 } 4756 4757 if (pset->num_permitted_admin > 0) { 4758 permit_adm = 0; 4759 for (i = 0; i < pset->num_permitted_admin; i++) { 4760 perm = &pset->permitted_admin[i]; 4761 if (open_match(perm, host, port)) { 4762 permit_adm = 1; 4763 break; 4764 } 4765 } 4766 } 4767 4768 if (!permit || !permit_adm) { 4769 logit("Received request from %.100s port %d to connect to " 4770 "host %.100s port %d, but the request was denied.", 4771 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4772 if (reason != NULL) 4773 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4774 return NULL; 4775 } 4776 4777 memset(&cctx, 0, sizeof(cctx)); 4778 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4779 &cctx, reason, errmsg); 4780 if (sock == -1) { 4781 channel_connect_ctx_free(&cctx); 4782 return NULL; 4783 } 4784 4785 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4786 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4787 c->host_port = port; 4788 c->path = xstrdup(host); 4789 c->connect_ctx = cctx; 4790 4791 return c; 4792 } 4793 4794 /* Check if connecting to that path is permitted and connect. */ 4795 Channel * 4796 channel_connect_to_path(struct ssh *ssh, const char *path, 4797 char *ctype, char *rname) 4798 { 4799 struct ssh_channels *sc = ssh->chanctxt; 4800 struct permission_set *pset = &sc->local_perms; 4801 u_int i, permit, permit_adm = 1; 4802 struct permission *perm; 4803 4804 permit = pset->all_permitted; 4805 if (!permit) { 4806 for (i = 0; i < pset->num_permitted_user; i++) { 4807 perm = &pset->permitted_user[i]; 4808 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4809 permit = 1; 4810 break; 4811 } 4812 } 4813 } 4814 4815 if (pset->num_permitted_admin > 0) { 4816 permit_adm = 0; 4817 for (i = 0; i < pset->num_permitted_admin; i++) { 4818 perm = &pset->permitted_admin[i]; 4819 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4820 permit_adm = 1; 4821 break; 4822 } 4823 } 4824 } 4825 4826 if (!permit || !permit_adm) { 4827 logit("Received request to connect to path %.100s, " 4828 "but the request was denied.", path); 4829 return NULL; 4830 } 4831 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4832 } 4833 4834 void 4835 channel_send_window_changes(struct ssh *ssh) 4836 { 4837 struct ssh_channels *sc = ssh->chanctxt; 4838 struct winsize ws; 4839 int r; 4840 u_int i; 4841 4842 for (i = 0; i < sc->channels_alloc; i++) { 4843 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4844 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4845 continue; 4846 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4847 continue; 4848 channel_request_start(ssh, i, "window-change", 0); 4849 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4850 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4851 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4852 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4853 (r = sshpkt_send(ssh)) != 0) 4854 fatal_fr(r, "channel %u; send window-change", i); 4855 } 4856 } 4857 4858 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4859 static Channel * 4860 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4861 { 4862 Channel *c; 4863 int r; 4864 4865 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4866 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4867 c->host_port = 0; 4868 c->path = NULL; 4869 4870 /* 4871 * We need to open the channel before we have a FD, 4872 * so that we can get SOCKS header from peer. 4873 */ 4874 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4875 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4876 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4877 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4878 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4879 fatal_fr(r, "channel %i; confirm", c->self); 4880 return c; 4881 } 4882 4883 /* Return CONNECTING socket to remote host:port or local socket path */ 4884 static int 4885 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4886 { 4887 struct ssh_channels *sc = ssh->chanctxt; 4888 struct permission_set *pset = &sc->local_perms; 4889 struct permission *perm; 4890 struct channel_connect cctx; 4891 u_int i, permit_adm = 1; 4892 int sock; 4893 4894 if (pset->num_permitted_admin > 0) { 4895 permit_adm = 0; 4896 for (i = 0; i < pset->num_permitted_admin; i++) { 4897 perm = &pset->permitted_admin[i]; 4898 if (open_match(perm, c->path, c->host_port)) { 4899 permit_adm = 1; 4900 break; 4901 } 4902 } 4903 } 4904 if (!permit_adm) { 4905 debug_f("requested forward not permitted"); 4906 return -1; 4907 } 4908 4909 memset(&cctx, 0, sizeof(cctx)); 4910 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4911 NULL, &cctx, NULL, NULL); 4912 if (sock == -1) 4913 channel_connect_ctx_free(&cctx); 4914 else { 4915 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4916 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4917 c->connect_ctx = cctx; 4918 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4919 } 4920 return sock; 4921 } 4922 4923 /* -- X11 forwarding */ 4924 4925 /* 4926 * Creates an internet domain socket for listening for X11 connections. 4927 * Returns 0 and a suitable display number for the DISPLAY variable 4928 * stored in display_numberp , or -1 if an error occurs. 4929 */ 4930 int 4931 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4932 int x11_use_localhost, int single_connection, 4933 u_int *display_numberp, int **chanids) 4934 { 4935 Channel *nc = NULL; 4936 int display_number, sock; 4937 u_short port; 4938 struct addrinfo hints, *ai, *aitop; 4939 char strport[NI_MAXSERV]; 4940 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4941 4942 if (chanids == NULL) 4943 return -1; 4944 4945 for (display_number = x11_display_offset; 4946 display_number < MAX_DISPLAYS; 4947 display_number++) { 4948 port = 6000 + display_number; 4949 memset(&hints, 0, sizeof(hints)); 4950 hints.ai_family = ssh->chanctxt->IPv4or6; 4951 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4952 hints.ai_socktype = SOCK_STREAM; 4953 snprintf(strport, sizeof strport, "%d", port); 4954 if ((gaierr = getaddrinfo(NULL, strport, 4955 &hints, &aitop)) != 0) { 4956 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4957 return -1; 4958 } 4959 for (ai = aitop; ai; ai = ai->ai_next) { 4960 if (ai->ai_family != AF_INET && 4961 ai->ai_family != AF_INET6) 4962 continue; 4963 sock = socket(ai->ai_family, ai->ai_socktype, 4964 ai->ai_protocol); 4965 if (sock == -1) { 4966 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 4967 #ifdef EPFNOSUPPORT 4968 && (errno != EPFNOSUPPORT) 4969 #endif 4970 ) { 4971 error("socket: %.100s", strerror(errno)); 4972 freeaddrinfo(aitop); 4973 return -1; 4974 } else { 4975 debug("x11_create_display_inet: Socket family %d not supported", 4976 ai->ai_family); 4977 continue; 4978 } 4979 } 4980 if (ai->ai_family == AF_INET6) 4981 sock_set_v6only(sock); 4982 if (x11_use_localhost) 4983 set_reuseaddr(sock); 4984 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4985 debug2_f("bind port %d: %.100s", port, 4986 strerror(errno)); 4987 close(sock); 4988 for (n = 0; n < num_socks; n++) 4989 close(socks[n]); 4990 num_socks = 0; 4991 break; 4992 } 4993 socks[num_socks++] = sock; 4994 if (num_socks == NUM_SOCKS) 4995 break; 4996 } 4997 freeaddrinfo(aitop); 4998 if (num_socks > 0) 4999 break; 5000 } 5001 if (display_number >= MAX_DISPLAYS) { 5002 error("Failed to allocate internet-domain X11 display socket."); 5003 return -1; 5004 } 5005 /* Start listening for connections on the socket. */ 5006 for (n = 0; n < num_socks; n++) { 5007 sock = socks[n]; 5008 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5009 error("listen: %.100s", strerror(errno)); 5010 close(sock); 5011 return -1; 5012 } 5013 } 5014 5015 /* Allocate a channel for each socket. */ 5016 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5017 for (n = 0; n < num_socks; n++) { 5018 sock = socks[n]; 5019 nc = channel_new(ssh, "x11-listener", 5020 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5021 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5022 0, "X11 inet listener", 1); 5023 nc->single_connection = single_connection; 5024 (*chanids)[n] = nc->self; 5025 } 5026 (*chanids)[n] = -1; 5027 5028 /* Return the display number for the DISPLAY environment variable. */ 5029 *display_numberp = display_number; 5030 return 0; 5031 } 5032 5033 static int 5034 connect_local_xsocket_path(const char *pathname) 5035 { 5036 int sock; 5037 struct sockaddr_un addr; 5038 5039 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5040 if (sock == -1) 5041 error("socket: %.100s", strerror(errno)); 5042 memset(&addr, 0, sizeof(addr)); 5043 addr.sun_family = AF_UNIX; 5044 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 5045 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5046 return sock; 5047 close(sock); 5048 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5049 return -1; 5050 } 5051 5052 static int 5053 connect_local_xsocket(u_int dnr) 5054 { 5055 char buf[1024]; 5056 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 5057 return connect_local_xsocket_path(buf); 5058 } 5059 5060 #ifdef __APPLE__ 5061 static int 5062 is_path_to_xsocket(const char *display, char *path, size_t pathlen) 5063 { 5064 struct stat sbuf; 5065 5066 if (strlcpy(path, display, pathlen) >= pathlen) { 5067 error("%s: display path too long", __func__); 5068 return 0; 5069 } 5070 if (display[0] != '/') 5071 return 0; 5072 if (stat(path, &sbuf) == 0) { 5073 return 1; 5074 } else { 5075 char *dot = strrchr(path, '.'); 5076 if (dot != NULL) { 5077 *dot = '\0'; 5078 if (stat(path, &sbuf) == 0) { 5079 return 1; 5080 } 5081 } 5082 } 5083 return 0; 5084 } 5085 #endif 5086 5087 int 5088 x11_connect_display(struct ssh *ssh) 5089 { 5090 u_int display_number; 5091 const char *display; 5092 char buf[1024], *cp; 5093 struct addrinfo hints, *ai, *aitop; 5094 char strport[NI_MAXSERV]; 5095 int gaierr, sock = 0; 5096 5097 /* Try to open a socket for the local X server. */ 5098 display = getenv("DISPLAY"); 5099 if (!display) { 5100 error("DISPLAY not set."); 5101 return -1; 5102 } 5103 /* 5104 * Now we decode the value of the DISPLAY variable and make a 5105 * connection to the real X server. 5106 */ 5107 5108 #ifdef __APPLE__ 5109 /* Check if display is a path to a socket (as set by launchd). */ 5110 { 5111 char path[PATH_MAX]; 5112 5113 if (is_path_to_xsocket(display, path, sizeof(path))) { 5114 debug("x11_connect_display: $DISPLAY is launchd"); 5115 5116 /* Create a socket. */ 5117 sock = connect_local_xsocket_path(path); 5118 if (sock < 0) 5119 return -1; 5120 5121 /* OK, we now have a connection to the display. */ 5122 return sock; 5123 } 5124 } 5125 #endif 5126 /* 5127 * Check if it is a unix domain socket. Unix domain displays are in 5128 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5129 */ 5130 if (strncmp(display, "unix:", 5) == 0 || 5131 display[0] == ':') { 5132 /* Connect to the unix domain socket. */ 5133 if (sscanf(strrchr(display, ':') + 1, "%u", 5134 &display_number) != 1) { 5135 error("Could not parse display number from DISPLAY: " 5136 "%.100s", display); 5137 return -1; 5138 } 5139 /* Create a socket. */ 5140 sock = connect_local_xsocket(display_number); 5141 if (sock < 0) 5142 return -1; 5143 5144 /* OK, we now have a connection to the display. */ 5145 return sock; 5146 } 5147 /* 5148 * Connect to an inet socket. The DISPLAY value is supposedly 5149 * hostname:d[.s], where hostname may also be numeric IP address. 5150 */ 5151 strlcpy(buf, display, sizeof(buf)); 5152 cp = strchr(buf, ':'); 5153 if (!cp) { 5154 error("Could not find ':' in DISPLAY: %.100s", display); 5155 return -1; 5156 } 5157 *cp = 0; 5158 /* 5159 * buf now contains the host name. But first we parse the 5160 * display number. 5161 */ 5162 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5163 error("Could not parse display number from DISPLAY: %.100s", 5164 display); 5165 return -1; 5166 } 5167 5168 /* Look up the host address */ 5169 memset(&hints, 0, sizeof(hints)); 5170 hints.ai_family = ssh->chanctxt->IPv4or6; 5171 hints.ai_socktype = SOCK_STREAM; 5172 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5173 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5174 error("%.100s: unknown host. (%s)", buf, 5175 ssh_gai_strerror(gaierr)); 5176 return -1; 5177 } 5178 for (ai = aitop; ai; ai = ai->ai_next) { 5179 /* Create a socket. */ 5180 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5181 if (sock == -1) { 5182 debug2("socket: %.100s", strerror(errno)); 5183 continue; 5184 } 5185 /* Connect it to the display. */ 5186 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5187 debug2("connect %.100s port %u: %.100s", buf, 5188 6000 + display_number, strerror(errno)); 5189 close(sock); 5190 continue; 5191 } 5192 /* Success */ 5193 break; 5194 } 5195 freeaddrinfo(aitop); 5196 if (!ai) { 5197 error("connect %.100s port %u: %.100s", buf, 5198 6000 + display_number, strerror(errno)); 5199 return -1; 5200 } 5201 set_nodelay(sock); 5202 return sock; 5203 } 5204 5205 /* 5206 * Requests forwarding of X11 connections, generates fake authentication 5207 * data, and enables authentication spoofing. 5208 * This should be called in the client only. 5209 */ 5210 void 5211 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5212 const char *disp, const char *proto, const char *data, int want_reply) 5213 { 5214 struct ssh_channels *sc = ssh->chanctxt; 5215 u_int data_len = (u_int) strlen(data) / 2; 5216 u_int i, value; 5217 const char *cp; 5218 char *new_data; 5219 int r, screen_number; 5220 5221 if (sc->x11_saved_display == NULL) 5222 sc->x11_saved_display = xstrdup(disp); 5223 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5224 error("x11_request_forwarding_with_spoofing: different " 5225 "$DISPLAY already forwarded"); 5226 return; 5227 } 5228 5229 cp = strchr(disp, ':'); 5230 if (cp) 5231 cp = strchr(cp, '.'); 5232 if (cp) 5233 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5234 else 5235 screen_number = 0; 5236 5237 if (sc->x11_saved_proto == NULL) { 5238 /* Save protocol name. */ 5239 sc->x11_saved_proto = xstrdup(proto); 5240 5241 /* Extract real authentication data. */ 5242 sc->x11_saved_data = xmalloc(data_len); 5243 for (i = 0; i < data_len; i++) { 5244 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5245 fatal("x11_request_forwarding: bad " 5246 "authentication data: %.100s", data); 5247 } 5248 sc->x11_saved_data[i] = value; 5249 } 5250 sc->x11_saved_data_len = data_len; 5251 5252 /* Generate fake data of the same length. */ 5253 sc->x11_fake_data = xmalloc(data_len); 5254 arc4random_buf(sc->x11_fake_data, data_len); 5255 sc->x11_fake_data_len = data_len; 5256 } 5257 5258 /* Convert the fake data into hex. */ 5259 new_data = tohex(sc->x11_fake_data, data_len); 5260 5261 /* Send the request packet. */ 5262 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5263 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5264 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5265 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5266 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5267 (r = sshpkt_send(ssh)) != 0 || 5268 (r = ssh_packet_write_wait(ssh)) != 0) 5269 fatal_fr(r, "send x11-req"); 5270 free(new_data); 5271 } 5272