1 /* $OpenBSD: channels.c,v 1.433 2023/09/04 00:01:46 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include "includes.h" 43 44 #include <sys/types.h> 45 #include <sys/stat.h> 46 #include <sys/ioctl.h> 47 #include <sys/un.h> 48 #include <sys/socket.h> 49 #ifdef HAVE_SYS_TIME_H 50 # include <sys/time.h> 51 #endif 52 53 #include <netinet/in.h> 54 #include <arpa/inet.h> 55 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <limits.h> 59 #include <netdb.h> 60 #ifdef HAVE_POLL_H 61 #include <poll.h> 62 #endif 63 #include <stdarg.h> 64 #ifdef HAVE_STDINT_H 65 # include <stdint.h> 66 #endif 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <string.h> 70 #include <termios.h> 71 #include <unistd.h> 72 73 #include "openbsd-compat/sys-queue.h" 74 #include "xmalloc.h" 75 #include "ssh.h" 76 #include "ssh2.h" 77 #include "ssherr.h" 78 #include "sshbuf.h" 79 #include "packet.h" 80 #include "log.h" 81 #include "misc.h" 82 #include "channels.h" 83 #include "compat.h" 84 #include "canohost.h" 85 #include "sshkey.h" 86 #include "authfd.h" 87 #include "pathnames.h" 88 #include "match.h" 89 90 /* XXX remove once we're satisfied there's no lurking bugs */ 91 /* #define DEBUG_CHANNEL_POLL 1 */ 92 93 /* -- agent forwarding */ 94 #define NUM_SOCKS 10 95 96 /* -- tcp forwarding */ 97 /* special-case port number meaning allow any port */ 98 #define FWD_PERMIT_ANY_PORT 0 99 100 /* special-case wildcard meaning allow any host */ 101 #define FWD_PERMIT_ANY_HOST "*" 102 103 /* -- X11 forwarding */ 104 /* Maximum number of fake X11 displays to try. */ 105 #define MAX_DISPLAYS 1000 106 107 /* Per-channel callback for pre/post IO actions */ 108 typedef void chan_fn(struct ssh *, Channel *c); 109 110 /* 111 * Data structure for storing which hosts are permitted for forward requests. 112 * The local sides of any remote forwards are stored in this array to prevent 113 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 114 * network (which might be behind a firewall). 115 */ 116 /* XXX: streamlocal wants a path instead of host:port */ 117 /* Overload host_to_connect; we could just make this match Forward */ 118 /* XXX - can we use listen_host instead of listen_path? */ 119 struct permission { 120 char *host_to_connect; /* Connect to 'host'. */ 121 int port_to_connect; /* Connect to 'port'. */ 122 char *listen_host; /* Remote side should listen address. */ 123 char *listen_path; /* Remote side should listen path. */ 124 int listen_port; /* Remote side should listen port. */ 125 Channel *downstream; /* Downstream mux*/ 126 }; 127 128 /* 129 * Stores the forwarding permission state for a single direction (local or 130 * remote). 131 */ 132 struct permission_set { 133 /* 134 * List of all local permitted host/port pairs to allow for the 135 * user. 136 */ 137 u_int num_permitted_user; 138 struct permission *permitted_user; 139 140 /* 141 * List of all permitted host/port pairs to allow for the admin. 142 */ 143 u_int num_permitted_admin; 144 struct permission *permitted_admin; 145 146 /* 147 * If this is true, all opens/listens are permitted. This is the 148 * case on the server on which we have to trust the client anyway, 149 * and the user could do anything after logging in. 150 */ 151 int all_permitted; 152 }; 153 154 /* Used to record timeouts per channel type */ 155 struct ssh_channel_timeout { 156 char *type_pattern; 157 int timeout_secs; 158 }; 159 160 /* Master structure for channels state */ 161 struct ssh_channels { 162 /* 163 * Pointer to an array containing all allocated channels. The array 164 * is dynamically extended as needed. 165 */ 166 Channel **channels; 167 168 /* 169 * Size of the channel array. All slots of the array must always be 170 * initialized (at least the type field); unused slots set to NULL 171 */ 172 u_int channels_alloc; 173 174 /* 175 * 'channel_pre*' are called just before IO to add any bits 176 * relevant to channels in the c->io_want bitmasks. 177 * 178 * 'channel_post*': perform any appropriate operations for 179 * channels which have c->io_ready events pending. 180 */ 181 chan_fn **channel_pre; 182 chan_fn **channel_post; 183 184 /* -- tcp forwarding */ 185 struct permission_set local_perms; 186 struct permission_set remote_perms; 187 188 /* -- X11 forwarding */ 189 190 /* Saved X11 local (client) display. */ 191 char *x11_saved_display; 192 193 /* Saved X11 authentication protocol name. */ 194 char *x11_saved_proto; 195 196 /* Saved X11 authentication data. This is the real data. */ 197 char *x11_saved_data; 198 u_int x11_saved_data_len; 199 200 /* Deadline after which all X11 connections are refused */ 201 time_t x11_refuse_time; 202 203 /* 204 * Fake X11 authentication data. This is what the server will be 205 * sending us; we should replace any occurrences of this by the 206 * real data. 207 */ 208 u_char *x11_fake_data; 209 u_int x11_fake_data_len; 210 211 /* AF_UNSPEC or AF_INET or AF_INET6 */ 212 int IPv4or6; 213 214 /* Channel timeouts by type */ 215 struct ssh_channel_timeout *timeouts; 216 size_t ntimeouts; 217 }; 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 int timeout_secs) 316 { 317 struct ssh_channels *sc = ssh->chanctxt; 318 319 debug2_f("channel type \"%s\" timeout %d seconds", 320 type_pattern, timeout_secs); 321 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 322 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 323 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 324 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 325 sc->ntimeouts++; 326 } 327 328 /* Clears all previously-added channel timeouts */ 329 void 330 channel_clear_timeouts(struct ssh *ssh) 331 { 332 struct ssh_channels *sc = ssh->chanctxt; 333 size_t i; 334 335 debug3_f("clearing"); 336 for (i = 0; i < sc->ntimeouts; i++) 337 free(sc->timeouts[i].type_pattern); 338 free(sc->timeouts); 339 sc->timeouts = NULL; 340 sc->ntimeouts = 0; 341 } 342 343 static int 344 lookup_timeout(struct ssh *ssh, const char *type) 345 { 346 struct ssh_channels *sc = ssh->chanctxt; 347 size_t i; 348 349 for (i = 0; i < sc->ntimeouts; i++) { 350 if (match_pattern(type, sc->timeouts[i].type_pattern)) 351 return sc->timeouts[i].timeout_secs; 352 } 353 354 return 0; 355 } 356 357 /* 358 * Sets "extended type" of a channel; used by session layer to add additional 359 * information about channel types (e.g. shell, login, subsystem) that can then 360 * be used to select timeouts. 361 * Will reset c->inactive_deadline as a side-effect. 362 */ 363 void 364 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 365 { 366 Channel *c; 367 368 if ((c = channel_by_id(ssh, id)) == NULL) 369 fatal_f("missing channel %d", id); 370 if (c->xctype != NULL) 371 free(c->xctype); 372 c->xctype = xstrdup(xctype); 373 /* Type has changed, so look up inactivity deadline again */ 374 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 375 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 376 c->inactive_deadline); 377 } 378 379 /* 380 * 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 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 391 if (wfd != -1 && wfd != rfd) 392 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 393 if (efd != -1 && efd != rfd && efd != wfd) 394 (void)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 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, int 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, port_to_connect == PORT_STREAMLOCAL ? 1655 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1656 1657 return c; 1658 } 1659 1660 /* dynamic port forwarding */ 1661 static void 1662 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1663 { 1664 const u_char *p; 1665 u_int have; 1666 int ret; 1667 1668 c->io_want = 0; 1669 have = sshbuf_len(c->input); 1670 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1671 /* sshbuf_dump(c->input, stderr); */ 1672 /* check if the fixed size part of the packet is in buffer. */ 1673 if (have < 3) { 1674 /* need more */ 1675 c->io_want |= SSH_CHAN_IO_RFD; 1676 return; 1677 } 1678 /* try to guess the protocol */ 1679 p = sshbuf_ptr(c->input); 1680 /* XXX sshbuf_peek_u8? */ 1681 switch (p[0]) { 1682 case 0x04: 1683 ret = channel_decode_socks4(c, c->input, c->output); 1684 break; 1685 case 0x05: 1686 ret = channel_decode_socks5(c, c->input, c->output); 1687 break; 1688 default: 1689 ret = -1; 1690 break; 1691 } 1692 if (ret < 0) { 1693 chan_mark_dead(ssh, c); 1694 } else if (ret == 0) { 1695 debug2("channel %d: pre_dynamic: need more", c->self); 1696 /* need more */ 1697 c->io_want |= SSH_CHAN_IO_RFD; 1698 if (sshbuf_len(c->output)) 1699 c->io_want |= SSH_CHAN_IO_WFD; 1700 } else { 1701 /* switch to the next state */ 1702 c->type = SSH_CHANNEL_OPENING; 1703 port_open_helper(ssh, c, "direct-tcpip"); 1704 } 1705 } 1706 1707 /* simulate read-error */ 1708 static void 1709 rdynamic_close(struct ssh *ssh, Channel *c) 1710 { 1711 c->type = SSH_CHANNEL_OPEN; 1712 channel_force_close(ssh, c, 0); 1713 } 1714 1715 /* reverse dynamic port forwarding */ 1716 static void 1717 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1718 { 1719 const u_char *p; 1720 u_int have, len; 1721 int r, ret; 1722 1723 have = sshbuf_len(c->output); 1724 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1725 /* sshbuf_dump(c->output, stderr); */ 1726 /* EOF received */ 1727 if (c->flags & CHAN_EOF_RCVD) { 1728 if ((r = sshbuf_consume(c->output, have)) != 0) 1729 fatal_fr(r, "channel %d: consume", c->self); 1730 rdynamic_close(ssh, c); 1731 return; 1732 } 1733 /* check if the fixed size part of the packet is in buffer. */ 1734 if (have < 3) 1735 return; 1736 /* try to guess the protocol */ 1737 p = sshbuf_ptr(c->output); 1738 switch (p[0]) { 1739 case 0x04: 1740 /* switch input/output for reverse forwarding */ 1741 ret = channel_decode_socks4(c, c->output, c->input); 1742 break; 1743 case 0x05: 1744 ret = channel_decode_socks5(c, c->output, c->input); 1745 break; 1746 default: 1747 ret = -1; 1748 break; 1749 } 1750 if (ret < 0) { 1751 rdynamic_close(ssh, c); 1752 } else if (ret == 0) { 1753 debug2("channel %d: pre_rdynamic: need more", c->self); 1754 /* send socks request to peer */ 1755 len = sshbuf_len(c->input); 1756 if (len > 0 && len < c->remote_window) { 1757 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1758 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1759 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1760 (r = sshpkt_send(ssh)) != 0) { 1761 fatal_fr(r, "channel %i: rdynamic", c->self); 1762 } 1763 if ((r = sshbuf_consume(c->input, len)) != 0) 1764 fatal_fr(r, "channel %d: consume", c->self); 1765 c->remote_window -= len; 1766 } 1767 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1768 /* the connect failed */ 1769 rdynamic_close(ssh, c); 1770 } 1771 } 1772 1773 /* This is our fake X11 server socket. */ 1774 static void 1775 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1776 { 1777 Channel *nc; 1778 struct sockaddr_storage addr; 1779 int r, newsock, oerrno, remote_port; 1780 socklen_t addrlen; 1781 char buf[16384], *remote_ipaddr; 1782 1783 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1784 return; 1785 1786 debug("X11 connection requested."); 1787 addrlen = sizeof(addr); 1788 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1789 if (c->single_connection) { 1790 oerrno = errno; 1791 debug2("single_connection: closing X11 listener."); 1792 channel_close_fd(ssh, c, &c->sock); 1793 chan_mark_dead(ssh, c); 1794 errno = oerrno; 1795 } 1796 if (newsock == -1) { 1797 if (errno != EINTR && errno != EWOULDBLOCK && 1798 errno != ECONNABORTED) 1799 error("accept: %.100s", strerror(errno)); 1800 if (errno == EMFILE || errno == ENFILE) 1801 c->notbefore = monotime() + 1; 1802 return; 1803 } 1804 set_nodelay(newsock); 1805 remote_ipaddr = get_peer_ipaddr(newsock); 1806 remote_port = get_peer_port(newsock); 1807 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1808 remote_ipaddr, remote_port); 1809 1810 nc = channel_new(ssh, "x11-connection", 1811 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1812 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1813 open_preamble(ssh, __func__, nc, "x11"); 1814 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1815 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1816 fatal_fr(r, "channel %i: reply", c->self); 1817 } 1818 if ((r = sshpkt_send(ssh)) != 0) 1819 fatal_fr(r, "channel %i: send", c->self); 1820 free(remote_ipaddr); 1821 } 1822 1823 static void 1824 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1825 { 1826 char *local_ipaddr = get_local_ipaddr(c->sock); 1827 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1828 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1829 int remote_port = get_peer_port(c->sock); 1830 int r; 1831 1832 if (remote_port == -1) { 1833 /* Fake addr/port to appease peers that validate it (Tectia) */ 1834 free(remote_ipaddr); 1835 remote_ipaddr = xstrdup("127.0.0.1"); 1836 remote_port = 65535; 1837 } 1838 1839 free(c->remote_name); 1840 xasprintf(&c->remote_name, 1841 "%s: listening port %d for %.100s port %d, " 1842 "connect from %.200s port %d to %.100s port %d", 1843 rtype, c->listening_port, c->path, c->host_port, 1844 remote_ipaddr, remote_port, local_ipaddr, local_port); 1845 1846 open_preamble(ssh, __func__, c, rtype); 1847 if (strcmp(rtype, "direct-tcpip") == 0) { 1848 /* target host, port */ 1849 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1850 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1851 fatal_fr(r, "channel %i: reply", c->self); 1852 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1853 /* target path */ 1854 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1855 fatal_fr(r, "channel %i: reply", c->self); 1856 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1857 /* listen path */ 1858 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1859 fatal_fr(r, "channel %i: reply", c->self); 1860 } else { 1861 /* listen address, port */ 1862 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1863 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1864 fatal_fr(r, "channel %i: reply", c->self); 1865 } 1866 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1867 /* reserved for future owner/mode info */ 1868 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1869 fatal_fr(r, "channel %i: reply", c->self); 1870 } else { 1871 /* originator host and port */ 1872 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1873 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1874 fatal_fr(r, "channel %i: reply", c->self); 1875 } 1876 if ((r = sshpkt_send(ssh)) != 0) 1877 fatal_fr(r, "channel %i: send", c->self); 1878 free(remote_ipaddr); 1879 free(local_ipaddr); 1880 } 1881 1882 void 1883 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1884 { 1885 ssh->chanctxt->x11_refuse_time = refuse_time; 1886 } 1887 1888 /* 1889 * This socket is listening for connections to a forwarded TCP/IP port. 1890 */ 1891 static void 1892 channel_post_port_listener(struct ssh *ssh, Channel *c) 1893 { 1894 Channel *nc; 1895 struct sockaddr_storage addr; 1896 int newsock, nextstate; 1897 socklen_t addrlen; 1898 char *rtype; 1899 1900 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1901 return; 1902 1903 debug("Connection to port %d forwarding to %.100s port %d requested.", 1904 c->listening_port, c->path, c->host_port); 1905 1906 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1907 nextstate = SSH_CHANNEL_OPENING; 1908 rtype = "forwarded-tcpip"; 1909 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1910 nextstate = SSH_CHANNEL_OPENING; 1911 rtype = "forwarded-streamlocal@openssh.com"; 1912 } else if (c->host_port == PORT_STREAMLOCAL) { 1913 nextstate = SSH_CHANNEL_OPENING; 1914 rtype = "direct-streamlocal@openssh.com"; 1915 } else if (c->host_port == 0) { 1916 nextstate = SSH_CHANNEL_DYNAMIC; 1917 rtype = "dynamic-tcpip"; 1918 } else { 1919 nextstate = SSH_CHANNEL_OPENING; 1920 rtype = "direct-tcpip"; 1921 } 1922 1923 addrlen = sizeof(addr); 1924 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1925 if (newsock == -1) { 1926 if (errno != EINTR && errno != EWOULDBLOCK && 1927 errno != ECONNABORTED) 1928 error("accept: %.100s", strerror(errno)); 1929 if (errno == EMFILE || errno == ENFILE) 1930 c->notbefore = monotime() + 1; 1931 return; 1932 } 1933 if (c->host_port != PORT_STREAMLOCAL) 1934 set_nodelay(newsock); 1935 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1936 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1937 nc->listening_port = c->listening_port; 1938 nc->host_port = c->host_port; 1939 if (c->path != NULL) 1940 nc->path = xstrdup(c->path); 1941 1942 if (nextstate != SSH_CHANNEL_DYNAMIC) 1943 port_open_helper(ssh, nc, rtype); 1944 } 1945 1946 /* 1947 * This is the authentication agent socket listening for connections from 1948 * clients. 1949 */ 1950 static void 1951 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1952 { 1953 Channel *nc; 1954 int r, newsock; 1955 struct sockaddr_storage addr; 1956 socklen_t addrlen; 1957 1958 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1959 return; 1960 1961 addrlen = sizeof(addr); 1962 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1963 if (newsock == -1) { 1964 error("accept from auth socket: %.100s", strerror(errno)); 1965 if (errno == EMFILE || errno == ENFILE) 1966 c->notbefore = monotime() + 1; 1967 return; 1968 } 1969 nc = channel_new(ssh, "agent-connection", 1970 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1971 c->local_window_max, c->local_maxpacket, 1972 0, "accepted auth socket", 1); 1973 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1974 if ((r = sshpkt_send(ssh)) != 0) 1975 fatal_fr(r, "channel %i", c->self); 1976 } 1977 1978 static void 1979 channel_post_connecting(struct ssh *ssh, Channel *c) 1980 { 1981 int err = 0, sock, isopen, r; 1982 socklen_t sz = sizeof(err); 1983 1984 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 1985 return; 1986 if (!c->have_remote_id) 1987 fatal_f("channel %d: no remote id", c->self); 1988 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1989 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1990 1991 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 1992 err = errno; 1993 error("getsockopt SO_ERROR failed"); 1994 } 1995 1996 if (err == 0) { 1997 /* Non-blocking connection completed */ 1998 debug("channel %d: connected to %s port %d", 1999 c->self, c->connect_ctx.host, c->connect_ctx.port); 2000 channel_connect_ctx_free(&c->connect_ctx); 2001 c->type = SSH_CHANNEL_OPEN; 2002 c->lastused = monotime(); 2003 if (isopen) { 2004 /* no message necessary */ 2005 } else { 2006 if ((r = sshpkt_start(ssh, 2007 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2008 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2009 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2010 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2011 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2012 (r = sshpkt_send(ssh)) != 0) 2013 fatal_fr(r, "channel %i open confirm", c->self); 2014 } 2015 return; 2016 } 2017 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2018 return; 2019 2020 /* Non-blocking connection failed */ 2021 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2022 2023 /* Try next address, if any */ 2024 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2025 /* Exhausted all addresses for this destination */ 2026 error("connect_to %.100s port %d: failed.", 2027 c->connect_ctx.host, c->connect_ctx.port); 2028 channel_connect_ctx_free(&c->connect_ctx); 2029 if (isopen) { 2030 rdynamic_close(ssh, c); 2031 } else { 2032 if ((r = sshpkt_start(ssh, 2033 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2034 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2035 (r = sshpkt_put_u32(ssh, 2036 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2037 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2038 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2039 (r = sshpkt_send(ssh)) != 0) 2040 fatal_fr(r, "channel %i: failure", c->self); 2041 chan_mark_dead(ssh, c); 2042 } 2043 } 2044 2045 /* New non-blocking connection in progress */ 2046 close(c->sock); 2047 c->sock = c->rfd = c->wfd = sock; 2048 } 2049 2050 static int 2051 channel_handle_rfd(struct ssh *ssh, Channel *c) 2052 { 2053 char buf[CHAN_RBUF]; 2054 ssize_t len; 2055 int r, force; 2056 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2057 int pty_zeroread = 0; 2058 2059 #ifdef PTY_ZEROREAD 2060 /* Bug on AIX: read(1) can return 0 for a non-closed fd */ 2061 pty_zeroread = c->isatty; 2062 #endif 2063 2064 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2065 2066 if (!force && (c->io_ready & SSH_CHAN_IO_RFD) == 0) 2067 return 1; 2068 if ((avail = sshbuf_avail(c->input)) == 0) 2069 return 1; /* Shouldn't happen */ 2070 2071 /* 2072 * For "simple" channels (i.e. not datagram or filtered), we can 2073 * read directly to the channel buffer. 2074 */ 2075 if (!pty_zeroread && c->input_filter == NULL && !c->datagram) { 2076 /* Only OPEN channels have valid rwin */ 2077 if (c->type == SSH_CHANNEL_OPEN) { 2078 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2079 return 1; /* shouldn't happen */ 2080 if (maxlen > c->remote_window - have) 2081 maxlen = c->remote_window - have; 2082 } 2083 if (maxlen > avail) 2084 maxlen = avail; 2085 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2086 if (errno == EINTR || (!force && 2087 (errno == EAGAIN || errno == EWOULDBLOCK))) 2088 return 1; 2089 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2090 c->self, c->rfd, maxlen, ssh_err(r)); 2091 goto rfail; 2092 } 2093 if (nr != 0) 2094 c->lastused = monotime(); 2095 return 1; 2096 } 2097 2098 errno = 0; 2099 len = read(c->rfd, buf, sizeof(buf)); 2100 /* fixup AIX zero-length read with errno set to look more like errors */ 2101 if (pty_zeroread && len == 0 && errno != 0) 2102 len = -1; 2103 if (len == -1 && (errno == EINTR || 2104 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 2105 return 1; 2106 if (len < 0 || (!pty_zeroread && len == 0)) { 2107 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2108 c->self, c->rfd, len, 2109 len == 0 ? "closed" : strerror(errno)); 2110 rfail: 2111 if (c->type != SSH_CHANNEL_OPEN) { 2112 debug2("channel %d: not open", c->self); 2113 chan_mark_dead(ssh, c); 2114 return -1; 2115 } else { 2116 chan_read_failed(ssh, c); 2117 } 2118 return -1; 2119 } 2120 c->lastused = monotime(); 2121 if (c->input_filter != NULL) { 2122 if (c->input_filter(ssh, c, buf, len) == -1) { 2123 debug2("channel %d: filter stops", c->self); 2124 chan_read_failed(ssh, c); 2125 } 2126 } else if (c->datagram) { 2127 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2128 fatal_fr(r, "channel %i: put datagram", c->self); 2129 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2130 fatal_fr(r, "channel %i: put data", c->self); 2131 2132 return 1; 2133 } 2134 2135 static int 2136 channel_handle_wfd(struct ssh *ssh, Channel *c) 2137 { 2138 struct termios tio; 2139 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2140 size_t dlen, olen = 0; 2141 int r, len; 2142 2143 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2144 return 1; 2145 if (sshbuf_len(c->output) == 0) 2146 return 1; 2147 2148 /* Send buffered output data to the socket. */ 2149 olen = sshbuf_len(c->output); 2150 if (c->output_filter != NULL) { 2151 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2152 debug2("channel %d: filter stops", c->self); 2153 if (c->type != SSH_CHANNEL_OPEN) 2154 chan_mark_dead(ssh, c); 2155 else 2156 chan_write_failed(ssh, c); 2157 return -1; 2158 } 2159 } else if (c->datagram) { 2160 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2161 fatal_fr(r, "channel %i: get datagram", c->self); 2162 buf = data; 2163 } else { 2164 buf = data = sshbuf_mutable_ptr(c->output); 2165 dlen = sshbuf_len(c->output); 2166 } 2167 2168 if (c->datagram) { 2169 /* ignore truncated writes, datagrams might get lost */ 2170 len = write(c->wfd, buf, dlen); 2171 free(data); 2172 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2173 errno == EWOULDBLOCK)) 2174 return 1; 2175 if (len <= 0) 2176 goto write_fail; 2177 goto out; 2178 } 2179 2180 #ifdef _AIX 2181 /* XXX: Later AIX versions can't push as much data to tty */ 2182 if (c->wfd_isatty) 2183 dlen = MINIMUM(dlen, 8*1024); 2184 #endif 2185 2186 len = write(c->wfd, buf, dlen); 2187 if (len == -1 && 2188 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 2189 return 1; 2190 if (len <= 0) { 2191 write_fail: 2192 if (c->type != SSH_CHANNEL_OPEN) { 2193 debug2("channel %d: not open", c->self); 2194 chan_mark_dead(ssh, c); 2195 return -1; 2196 } else { 2197 chan_write_failed(ssh, c); 2198 } 2199 return -1; 2200 } 2201 c->lastused = monotime(); 2202 #ifndef BROKEN_TCGETATTR_ICANON 2203 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2204 if (tcgetattr(c->wfd, &tio) == 0 && 2205 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2206 /* 2207 * Simulate echo to reduce the impact of 2208 * traffic analysis. We need to match the 2209 * size of a SSH2_MSG_CHANNEL_DATA message 2210 * (4 byte channel id + buf) 2211 */ 2212 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2213 (r = sshpkt_send(ssh)) != 0) 2214 fatal_fr(r, "channel %i: ignore", c->self); 2215 } 2216 } 2217 #endif /* BROKEN_TCGETATTR_ICANON */ 2218 if ((r = sshbuf_consume(c->output, len)) != 0) 2219 fatal_fr(r, "channel %i: consume", c->self); 2220 out: 2221 c->local_consumed += olen - sshbuf_len(c->output); 2222 2223 return 1; 2224 } 2225 2226 static int 2227 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2228 { 2229 int r; 2230 ssize_t len; 2231 2232 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2233 return 1; 2234 if (sshbuf_len(c->extended) == 0) 2235 return 1; 2236 2237 len = write(c->efd, sshbuf_ptr(c->extended), 2238 sshbuf_len(c->extended)); 2239 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2240 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2241 errno == EWOULDBLOCK)) 2242 return 1; 2243 if (len <= 0) { 2244 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2245 channel_close_fd(ssh, c, &c->efd); 2246 } else { 2247 if ((r = sshbuf_consume(c->extended, len)) != 0) 2248 fatal_fr(r, "channel %i: consume", c->self); 2249 c->local_consumed += len; 2250 c->lastused = monotime(); 2251 } 2252 return 1; 2253 } 2254 2255 static int 2256 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2257 { 2258 char buf[CHAN_RBUF]; 2259 ssize_t len; 2260 int r, force; 2261 2262 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2263 2264 if (!force && (c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2265 return 1; 2266 2267 len = read(c->efd, buf, sizeof(buf)); 2268 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2269 if (len == -1 && (errno == EINTR || ((errno == EAGAIN || 2270 errno == EWOULDBLOCK) && !force))) 2271 return 1; 2272 if (len <= 0) { 2273 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2274 channel_close_fd(ssh, c, &c->efd); 2275 return 1; 2276 } 2277 c->lastused = monotime(); 2278 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2279 debug3("channel %d: discard efd", c->self); 2280 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2281 fatal_fr(r, "channel %i: append", c->self); 2282 return 1; 2283 } 2284 2285 static int 2286 channel_handle_efd(struct ssh *ssh, Channel *c) 2287 { 2288 if (c->efd == -1) 2289 return 1; 2290 2291 /** XXX handle drain efd, too */ 2292 2293 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2294 return channel_handle_efd_write(ssh, c); 2295 else if (c->extended_usage == CHAN_EXTENDED_READ || 2296 c->extended_usage == CHAN_EXTENDED_IGNORE) 2297 return channel_handle_efd_read(ssh, c); 2298 2299 return 1; 2300 } 2301 2302 static int 2303 channel_check_window(struct ssh *ssh, Channel *c) 2304 { 2305 int r; 2306 2307 if (c->type == SSH_CHANNEL_OPEN && 2308 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2309 ((c->local_window_max - c->local_window > 2310 c->local_maxpacket*3) || 2311 c->local_window < c->local_window_max/2) && 2312 c->local_consumed > 0) { 2313 if (!c->have_remote_id) 2314 fatal_f("channel %d: no remote id", c->self); 2315 if ((r = sshpkt_start(ssh, 2316 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2317 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2318 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2319 (r = sshpkt_send(ssh)) != 0) { 2320 fatal_fr(r, "channel %i", c->self); 2321 } 2322 debug2("channel %d: window %d sent adjust %d", c->self, 2323 c->local_window, c->local_consumed); 2324 c->local_window += c->local_consumed; 2325 c->local_consumed = 0; 2326 } 2327 return 1; 2328 } 2329 2330 static void 2331 channel_post_open(struct ssh *ssh, Channel *c) 2332 { 2333 channel_handle_rfd(ssh, c); 2334 channel_handle_wfd(ssh, c); 2335 channel_handle_efd(ssh, c); 2336 channel_check_window(ssh, c); 2337 } 2338 2339 static u_int 2340 read_mux(struct ssh *ssh, Channel *c, u_int need) 2341 { 2342 char buf[CHAN_RBUF]; 2343 ssize_t len; 2344 u_int rlen; 2345 int r; 2346 2347 if (sshbuf_len(c->input) < need) { 2348 rlen = need - sshbuf_len(c->input); 2349 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2350 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2351 return sshbuf_len(c->input); 2352 if (len <= 0) { 2353 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2354 c->self, c->rfd, len); 2355 chan_read_failed(ssh, c); 2356 return 0; 2357 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2358 fatal_fr(r, "channel %i: append", c->self); 2359 } 2360 return sshbuf_len(c->input); 2361 } 2362 2363 static void 2364 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2365 { 2366 u_int need; 2367 2368 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2369 return; 2370 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2371 return; 2372 if (c->mux_pause) 2373 return; 2374 2375 /* 2376 * Don't not read past the precise end of packets to 2377 * avoid disrupting fd passing. 2378 */ 2379 if (read_mux(ssh, c, 4) < 4) /* read header */ 2380 return; 2381 /* XXX sshbuf_peek_u32 */ 2382 need = PEEK_U32(sshbuf_ptr(c->input)); 2383 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2384 if (need > CHANNEL_MUX_MAX_PACKET) { 2385 debug2("channel %d: packet too big %u > %u", 2386 c->self, CHANNEL_MUX_MAX_PACKET, need); 2387 chan_rcvd_oclose(ssh, c); 2388 return; 2389 } 2390 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2391 return; 2392 if (c->mux_rcb(ssh, c) != 0) { 2393 debug("channel %d: mux_rcb failed", c->self); 2394 chan_mark_dead(ssh, c); 2395 return; 2396 } 2397 } 2398 2399 static void 2400 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2401 { 2402 ssize_t len; 2403 int r; 2404 2405 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2406 return; 2407 if (sshbuf_len(c->output) == 0) 2408 return; 2409 2410 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2411 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2412 return; 2413 if (len <= 0) { 2414 chan_mark_dead(ssh, c); 2415 return; 2416 } 2417 if ((r = sshbuf_consume(c->output, len)) != 0) 2418 fatal_fr(r, "channel %i: consume", c->self); 2419 } 2420 2421 static void 2422 channel_post_mux_client(struct ssh *ssh, Channel *c) 2423 { 2424 channel_post_mux_client_read(ssh, c); 2425 channel_post_mux_client_write(ssh, c); 2426 } 2427 2428 static void 2429 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2430 { 2431 Channel *nc; 2432 struct sockaddr_storage addr; 2433 socklen_t addrlen; 2434 int newsock; 2435 uid_t euid; 2436 gid_t egid; 2437 2438 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2439 return; 2440 2441 debug("multiplexing control connection"); 2442 2443 /* 2444 * Accept connection on control socket 2445 */ 2446 memset(&addr, 0, sizeof(addr)); 2447 addrlen = sizeof(addr); 2448 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2449 &addrlen)) == -1) { 2450 error_f("accept: %s", strerror(errno)); 2451 if (errno == EMFILE || errno == ENFILE) 2452 c->notbefore = monotime() + 1; 2453 return; 2454 } 2455 2456 if (getpeereid(newsock, &euid, &egid) == -1) { 2457 error_f("getpeereid failed: %s", strerror(errno)); 2458 close(newsock); 2459 return; 2460 } 2461 if ((euid != 0) && (getuid() != euid)) { 2462 error("multiplex uid mismatch: peer euid %u != uid %u", 2463 (u_int)euid, (u_int)getuid()); 2464 close(newsock); 2465 return; 2466 } 2467 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2468 newsock, newsock, -1, c->local_window_max, 2469 c->local_maxpacket, 0, "mux-control", 1); 2470 nc->mux_rcb = c->mux_rcb; 2471 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2472 /* establish state */ 2473 nc->mux_rcb(ssh, nc); 2474 /* mux state transitions must not elicit protocol messages */ 2475 nc->flags |= CHAN_LOCAL; 2476 } 2477 2478 static void 2479 channel_handler_init(struct ssh_channels *sc) 2480 { 2481 chan_fn **pre, **post; 2482 2483 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2484 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2485 fatal_f("allocation failed"); 2486 2487 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2488 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2489 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2490 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2491 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2492 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2493 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2494 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2495 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2496 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2497 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2498 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2499 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2500 2501 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2502 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2503 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2504 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2505 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2506 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2507 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2508 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2509 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2510 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2511 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2512 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2513 2514 sc->channel_pre = pre; 2515 sc->channel_post = post; 2516 } 2517 2518 /* gc dead channels */ 2519 static void 2520 channel_garbage_collect(struct ssh *ssh, Channel *c) 2521 { 2522 if (c == NULL) 2523 return; 2524 if (c->detach_user != NULL) { 2525 if (!chan_is_dead(ssh, c, c->detach_close)) 2526 return; 2527 2528 debug2("channel %d: gc: notify user", c->self); 2529 c->detach_user(ssh, c->self, 0, NULL); 2530 /* if we still have a callback */ 2531 if (c->detach_user != NULL) 2532 return; 2533 debug2("channel %d: gc: user detached", c->self); 2534 } 2535 if (!chan_is_dead(ssh, c, 1)) 2536 return; 2537 debug2("channel %d: garbage collecting", c->self); 2538 channel_free(ssh, c); 2539 } 2540 2541 enum channel_table { CHAN_PRE, CHAN_POST }; 2542 2543 static void 2544 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2545 { 2546 struct ssh_channels *sc = ssh->chanctxt; 2547 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2548 u_int i, oalloc; 2549 Channel *c; 2550 time_t now; 2551 2552 now = monotime(); 2553 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2554 c = sc->channels[i]; 2555 if (c == NULL) 2556 continue; 2557 /* Try to keep IO going while rekeying */ 2558 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2559 continue; 2560 if (c->delayed) { 2561 if (table == CHAN_PRE) 2562 c->delayed = 0; 2563 else 2564 continue; 2565 } 2566 if (ftab[c->type] != NULL) { 2567 if (table == CHAN_PRE && 2568 c->type == SSH_CHANNEL_OPEN && 2569 c->inactive_deadline != 0 && c->lastused != 0 && 2570 now >= c->lastused + c->inactive_deadline) { 2571 /* channel closed for inactivity */ 2572 verbose("channel %d: closing after %u seconds " 2573 "of inactivity", c->self, 2574 c->inactive_deadline); 2575 channel_force_close(ssh, c, 1); 2576 } else if (c->notbefore <= now) { 2577 /* Run handlers that are not paused. */ 2578 (*ftab[c->type])(ssh, c); 2579 /* inactivity timeouts must interrupt poll() */ 2580 if (timeout != NULL && 2581 c->type == SSH_CHANNEL_OPEN && 2582 c->lastused != 0 && 2583 c->inactive_deadline != 0) { 2584 ptimeout_deadline_monotime(timeout, 2585 c->lastused + c->inactive_deadline); 2586 } 2587 } else if (timeout != NULL) { 2588 /* 2589 * Arrange for poll() wakeup when channel pause 2590 * timer expires. 2591 */ 2592 ptimeout_deadline_monotime(timeout, 2593 c->notbefore); 2594 } 2595 } 2596 channel_garbage_collect(ssh, c); 2597 } 2598 } 2599 2600 /* 2601 * Create sockets before preparing IO. 2602 * This is necessary for things that need to happen after reading 2603 * the network-input but need to be completed before IO event setup, e.g. 2604 * because they may create new channels. 2605 */ 2606 static void 2607 channel_before_prepare_io(struct ssh *ssh) 2608 { 2609 struct ssh_channels *sc = ssh->chanctxt; 2610 Channel *c; 2611 u_int i, oalloc; 2612 2613 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2614 c = sc->channels[i]; 2615 if (c == NULL) 2616 continue; 2617 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2618 channel_before_prepare_io_rdynamic(ssh, c); 2619 } 2620 } 2621 2622 static void 2623 dump_channel_poll(const char *func, const char *what, Channel *c, 2624 u_int pollfd_offset, struct pollfd *pfd) 2625 { 2626 #ifdef DEBUG_CHANNEL_POLL 2627 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2628 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2629 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2630 c->rfd, c->wfd, c->efd, c->sock, 2631 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2632 c->io_want, c->io_ready, 2633 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2634 #endif 2635 } 2636 2637 /* Prepare pollfd entries for a single channel */ 2638 static void 2639 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2640 struct pollfd *pfd, u_int npfd) 2641 { 2642 u_int ev, p = *next_pollfd; 2643 2644 if (c == NULL) 2645 return; 2646 if (p + 4 > npfd) { 2647 /* Shouldn't happen */ 2648 fatal_f("channel %d: bad pfd offset %u (max %u)", 2649 c->self, p, npfd); 2650 } 2651 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2652 /* 2653 * prepare c->rfd 2654 * 2655 * This is a special case, since c->rfd might be the same as 2656 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2657 * IO too. 2658 */ 2659 if (c->rfd != -1) { 2660 ev = 0; 2661 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2662 ev |= POLLIN; 2663 /* rfd == wfd */ 2664 if (c->wfd == c->rfd) { 2665 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2666 ev |= POLLOUT; 2667 } 2668 /* rfd == efd */ 2669 if (c->efd == c->rfd) { 2670 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2671 ev |= POLLIN; 2672 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2673 ev |= POLLOUT; 2674 } 2675 /* rfd == sock */ 2676 if (c->sock == c->rfd) { 2677 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2678 ev |= POLLIN; 2679 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2680 ev |= POLLOUT; 2681 } 2682 /* Pack a pfd entry if any event armed for this fd */ 2683 if (ev != 0) { 2684 c->pfds[0] = p; 2685 pfd[p].fd = c->rfd; 2686 pfd[p].events = ev; 2687 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2688 p++; 2689 } 2690 } 2691 /* prepare c->wfd if wanting IO and not already handled above */ 2692 if (c->wfd != -1 && c->rfd != c->wfd) { 2693 ev = 0; 2694 if ((c->io_want & SSH_CHAN_IO_WFD)) 2695 ev |= POLLOUT; 2696 /* Pack a pfd entry if any event armed for this fd */ 2697 if (ev != 0) { 2698 c->pfds[1] = p; 2699 pfd[p].fd = c->wfd; 2700 pfd[p].events = ev; 2701 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2702 p++; 2703 } 2704 } 2705 /* prepare c->efd if wanting IO and not already handled above */ 2706 if (c->efd != -1 && c->rfd != c->efd) { 2707 ev = 0; 2708 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2709 ev |= POLLIN; 2710 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2711 ev |= POLLOUT; 2712 /* Pack a pfd entry if any event armed for this fd */ 2713 if (ev != 0) { 2714 c->pfds[2] = p; 2715 pfd[p].fd = c->efd; 2716 pfd[p].events = ev; 2717 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2718 p++; 2719 } 2720 } 2721 /* prepare c->sock if wanting IO and not already handled above */ 2722 if (c->sock != -1 && c->rfd != c->sock) { 2723 ev = 0; 2724 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2725 ev |= POLLIN; 2726 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2727 ev |= POLLOUT; 2728 /* Pack a pfd entry if any event armed for this fd */ 2729 if (ev != 0) { 2730 c->pfds[3] = p; 2731 pfd[p].fd = c->sock; 2732 pfd[p].events = 0; 2733 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2734 p++; 2735 } 2736 } 2737 *next_pollfd = p; 2738 } 2739 2740 /* * Allocate/prepare poll structure */ 2741 void 2742 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2743 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2744 { 2745 struct ssh_channels *sc = ssh->chanctxt; 2746 u_int i, oalloc, p, npfd = npfd_reserved; 2747 2748 channel_before_prepare_io(ssh); /* might create a new channel */ 2749 /* clear out I/O flags from last poll */ 2750 for (i = 0; i < sc->channels_alloc; i++) { 2751 if (sc->channels[i] == NULL) 2752 continue; 2753 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2754 } 2755 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2756 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2757 fatal_f("too many channels"); /* shouldn't happen */ 2758 npfd += sc->channels_alloc * 4; 2759 if (npfd > *npfd_allocp) { 2760 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2761 npfd, sizeof(**pfdp)); 2762 *npfd_allocp = npfd; 2763 } 2764 *npfd_activep = npfd_reserved; 2765 oalloc = sc->channels_alloc; 2766 2767 channel_handler(ssh, CHAN_PRE, timeout); 2768 2769 if (oalloc != sc->channels_alloc) { 2770 /* shouldn't happen */ 2771 fatal_f("channels_alloc changed during CHAN_PRE " 2772 "(was %u, now %u)", oalloc, sc->channels_alloc); 2773 } 2774 2775 /* Prepare pollfd */ 2776 p = npfd_reserved; 2777 for (i = 0; i < sc->channels_alloc; i++) 2778 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2779 *npfd_activep = p; 2780 } 2781 2782 static void 2783 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2784 const char *what, u_int revents_mask, u_int ready) 2785 { 2786 struct pollfd *pfd = &pfds[p]; 2787 2788 if (fd == -1) 2789 return; 2790 if (p == -1 || (u_int)p >= npfd) 2791 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2792 dump_channel_poll(__func__, what, c, p, pfd); 2793 if (pfd->fd != fd) { 2794 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2795 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2796 c->rfd, c->wfd, c->efd, c->sock); 2797 } 2798 if ((pfd->revents & POLLNVAL) != 0) { 2799 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2800 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2801 } 2802 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2803 c->io_ready |= ready & c->io_want; 2804 } 2805 2806 /* 2807 * After poll, perform any appropriate operations for channels which have 2808 * events pending. 2809 */ 2810 void 2811 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2812 { 2813 struct ssh_channels *sc = ssh->chanctxt; 2814 u_int i; 2815 int p; 2816 Channel *c; 2817 2818 #ifdef DEBUG_CHANNEL_POLL 2819 for (p = 0; p < (int)npfd; p++) { 2820 if (pfd[p].revents == 0) 2821 continue; 2822 debug_f("pfd[%u].fd %d rev 0x%04x", 2823 p, pfd[p].fd, pfd[p].revents); 2824 } 2825 #endif 2826 2827 /* Convert pollfd into c->io_ready */ 2828 for (i = 0; i < sc->channels_alloc; i++) { 2829 c = sc->channels[i]; 2830 if (c == NULL) 2831 continue; 2832 /* if rfd is shared with efd/sock then wfd should be too */ 2833 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2834 (c->rfd == c->efd || c->rfd == c->sock)) { 2835 /* Shouldn't happen */ 2836 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2837 c->self, c->rfd, c->wfd, c->efd, c->sock); 2838 } 2839 c->io_ready = 0; 2840 /* rfd, potentially shared with wfd, efd and sock */ 2841 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2842 fd_ready(c, p, pfd, npfd, c->rfd, 2843 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2844 if (c->rfd == c->wfd) { 2845 fd_ready(c, p, pfd, npfd, c->wfd, 2846 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2847 } 2848 if (c->rfd == c->efd) { 2849 fd_ready(c, p, pfd, npfd, c->efd, 2850 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2851 fd_ready(c, p, pfd, npfd, c->efd, 2852 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2853 } 2854 if (c->rfd == c->sock) { 2855 fd_ready(c, p, pfd, npfd, c->sock, 2856 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2857 fd_ready(c, p, pfd, npfd, c->sock, 2858 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2859 } 2860 dump_channel_poll(__func__, "rfd", c, p, pfd); 2861 } 2862 /* wfd */ 2863 if (c->wfd != -1 && c->wfd != c->rfd && 2864 (p = c->pfds[1]) != -1) { 2865 fd_ready(c, p, pfd, npfd, c->wfd, 2866 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2867 dump_channel_poll(__func__, "wfd", c, p, pfd); 2868 } 2869 /* efd */ 2870 if (c->efd != -1 && c->efd != c->rfd && 2871 (p = c->pfds[2]) != -1) { 2872 fd_ready(c, p, pfd, npfd, c->efd, 2873 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2874 fd_ready(c, p, pfd, npfd, c->efd, 2875 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2876 dump_channel_poll(__func__, "efd", c, p, pfd); 2877 } 2878 /* sock */ 2879 if (c->sock != -1 && c->sock != c->rfd && 2880 (p = c->pfds[3]) != -1) { 2881 fd_ready(c, p, pfd, npfd, c->sock, 2882 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2883 fd_ready(c, p, pfd, npfd, c->sock, 2884 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2885 dump_channel_poll(__func__, "sock", c, p, pfd); 2886 } 2887 } 2888 channel_handler(ssh, CHAN_POST, NULL); 2889 } 2890 2891 /* 2892 * Enqueue data for channels with open or draining c->input. 2893 * Returns non-zero if a packet was enqueued. 2894 */ 2895 static int 2896 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2897 { 2898 size_t len, plen; 2899 const u_char *pkt; 2900 int r; 2901 2902 if ((len = sshbuf_len(c->input)) == 0) { 2903 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2904 /* 2905 * input-buffer is empty and read-socket shutdown: 2906 * tell peer, that we will not send more data: 2907 * send IEOF. 2908 * hack for extended data: delay EOF if EFD still 2909 * in use. 2910 */ 2911 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2912 debug2("channel %d: " 2913 "ibuf_empty delayed efd %d/(%zu)", 2914 c->self, c->efd, sshbuf_len(c->extended)); 2915 else 2916 chan_ibuf_empty(ssh, c); 2917 } 2918 return 0; 2919 } 2920 2921 if (!c->have_remote_id) 2922 fatal_f("channel %d: no remote id", c->self); 2923 2924 if (c->datagram) { 2925 /* Check datagram will fit; drop if not */ 2926 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2927 fatal_fr(r, "channel %i: get datagram", c->self); 2928 /* 2929 * XXX this does tail-drop on the datagram queue which is 2930 * usually suboptimal compared to head-drop. Better to have 2931 * backpressure at read time? (i.e. read + discard) 2932 */ 2933 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2934 debug("channel %d: datagram too big", c->self); 2935 return 0; 2936 } 2937 /* Enqueue it */ 2938 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2939 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2940 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2941 (r = sshpkt_send(ssh)) != 0) 2942 fatal_fr(r, "channel %i: send datagram", c->self); 2943 c->remote_window -= plen; 2944 return 1; 2945 } 2946 2947 /* Enqueue packet for buffered data. */ 2948 if (len > c->remote_window) 2949 len = c->remote_window; 2950 if (len > c->remote_maxpacket) 2951 len = c->remote_maxpacket; 2952 if (len == 0) 2953 return 0; 2954 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2955 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2956 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2957 (r = sshpkt_send(ssh)) != 0) 2958 fatal_fr(r, "channel %i: send data", c->self); 2959 if ((r = sshbuf_consume(c->input, len)) != 0) 2960 fatal_fr(r, "channel %i: consume", c->self); 2961 c->remote_window -= len; 2962 return 1; 2963 } 2964 2965 /* 2966 * Enqueue data for channels with open c->extended in read mode. 2967 * Returns non-zero if a packet was enqueued. 2968 */ 2969 static int 2970 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2971 { 2972 size_t len; 2973 int r; 2974 2975 if ((len = sshbuf_len(c->extended)) == 0) 2976 return 0; 2977 2978 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2979 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2980 if (len > c->remote_window) 2981 len = c->remote_window; 2982 if (len > c->remote_maxpacket) 2983 len = c->remote_maxpacket; 2984 if (len == 0) 2985 return 0; 2986 if (!c->have_remote_id) 2987 fatal_f("channel %d: no remote id", c->self); 2988 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2989 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2990 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2991 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2992 (r = sshpkt_send(ssh)) != 0) 2993 fatal_fr(r, "channel %i: data", c->self); 2994 if ((r = sshbuf_consume(c->extended, len)) != 0) 2995 fatal_fr(r, "channel %i: consume", c->self); 2996 c->remote_window -= len; 2997 debug2("channel %d: sent ext data %zu", c->self, len); 2998 return 1; 2999 } 3000 3001 /* 3002 * If there is data to send to the connection, enqueue some of it now. 3003 * Returns non-zero if data was enqueued. 3004 */ 3005 int 3006 channel_output_poll(struct ssh *ssh) 3007 { 3008 struct ssh_channels *sc = ssh->chanctxt; 3009 Channel *c; 3010 u_int i; 3011 int ret = 0; 3012 3013 for (i = 0; i < sc->channels_alloc; i++) { 3014 c = sc->channels[i]; 3015 if (c == NULL) 3016 continue; 3017 3018 /* 3019 * We are only interested in channels that can have buffered 3020 * incoming data. 3021 */ 3022 if (c->type != SSH_CHANNEL_OPEN) 3023 continue; 3024 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3025 /* XXX is this true? */ 3026 debug3("channel %d: will not send data after close", 3027 c->self); 3028 continue; 3029 } 3030 3031 /* Get the amount of buffered data for this channel. */ 3032 if (c->istate == CHAN_INPUT_OPEN || 3033 c->istate == CHAN_INPUT_WAIT_DRAIN) 3034 ret |= channel_output_poll_input_open(ssh, c); 3035 /* Send extended data, i.e. stderr */ 3036 if (!(c->flags & CHAN_EOF_SENT) && 3037 c->extended_usage == CHAN_EXTENDED_READ) 3038 ret |= channel_output_poll_extended_read(ssh, c); 3039 } 3040 return ret; 3041 } 3042 3043 /* -- mux proxy support */ 3044 3045 /* 3046 * When multiplexing channel messages for mux clients we have to deal 3047 * with downstream messages from the mux client and upstream messages 3048 * from the ssh server: 3049 * 1) Handling downstream messages is straightforward and happens 3050 * in channel_proxy_downstream(): 3051 * - We forward all messages (mostly) unmodified to the server. 3052 * - However, in order to route messages from upstream to the correct 3053 * downstream client, we have to replace the channel IDs used by the 3054 * mux clients with a unique channel ID because the mux clients might 3055 * use conflicting channel IDs. 3056 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3057 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3058 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3059 * with the newly allocated channel ID. 3060 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3061 * channels and processed by channel_proxy_upstream(). The local channel ID 3062 * is then translated back to the original mux client ID. 3063 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3064 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3065 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3066 * downstream mux client are removed. 3067 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3068 * requires more work, because they are not addressed to a specific 3069 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3070 * out whether the request is addressed to the local client or a 3071 * specific downstream client based on the listen-address/port. 3072 * 6) Agent and X11-Forwarding have a similar problem and are currently 3073 * not supported as the matching session/channel cannot be identified 3074 * easily. 3075 */ 3076 3077 /* 3078 * receive packets from downstream mux clients: 3079 * channel callback fired on read from mux client, creates 3080 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3081 * on channel creation. 3082 */ 3083 int 3084 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3085 { 3086 Channel *c = NULL; 3087 struct sshbuf *original = NULL, *modified = NULL; 3088 const u_char *cp; 3089 char *ctype = NULL, *listen_host = NULL; 3090 u_char type; 3091 size_t have; 3092 int ret = -1, r; 3093 u_int id, remote_id, listen_port; 3094 3095 /* sshbuf_dump(downstream->input, stderr); */ 3096 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3097 != 0) { 3098 error_fr(r, "parse"); 3099 return -1; 3100 } 3101 if (have < 2) { 3102 error_f("short message"); 3103 return -1; 3104 } 3105 type = cp[1]; 3106 /* skip padlen + type */ 3107 cp += 2; 3108 have -= 2; 3109 if (ssh_packet_log_type(type)) 3110 debug3_f("channel %u: down->up: type %u", 3111 downstream->self, type); 3112 3113 switch (type) { 3114 case SSH2_MSG_CHANNEL_OPEN: 3115 if ((original = sshbuf_from(cp, have)) == NULL || 3116 (modified = sshbuf_new()) == NULL) { 3117 error_f("alloc"); 3118 goto out; 3119 } 3120 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3121 (r = sshbuf_get_u32(original, &id)) != 0) { 3122 error_fr(r, "parse"); 3123 goto out; 3124 } 3125 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3126 -1, -1, -1, 0, 0, 0, ctype, 1); 3127 c->mux_ctx = downstream; /* point to mux client */ 3128 c->mux_downstream_id = id; /* original downstream id */ 3129 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3130 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3131 (r = sshbuf_putb(modified, original)) != 0) { 3132 error_fr(r, "compose"); 3133 channel_free(ssh, c); 3134 goto out; 3135 } 3136 break; 3137 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3138 /* 3139 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3140 * need to parse 'remote_id' instead of 'ctype'. 3141 */ 3142 if ((original = sshbuf_from(cp, have)) == NULL || 3143 (modified = sshbuf_new()) == NULL) { 3144 error_f("alloc"); 3145 goto out; 3146 } 3147 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3148 (r = sshbuf_get_u32(original, &id)) != 0) { 3149 error_fr(r, "parse"); 3150 goto out; 3151 } 3152 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3153 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3154 c->mux_ctx = downstream; /* point to mux client */ 3155 c->mux_downstream_id = id; 3156 c->remote_id = remote_id; 3157 c->have_remote_id = 1; 3158 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3159 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3160 (r = sshbuf_putb(modified, original)) != 0) { 3161 error_fr(r, "compose"); 3162 channel_free(ssh, c); 3163 goto out; 3164 } 3165 break; 3166 case SSH2_MSG_GLOBAL_REQUEST: 3167 if ((original = sshbuf_from(cp, have)) == NULL) { 3168 error_f("alloc"); 3169 goto out; 3170 } 3171 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3172 error_fr(r, "parse"); 3173 goto out; 3174 } 3175 if (strcmp(ctype, "tcpip-forward") != 0) { 3176 error_f("unsupported request %s", ctype); 3177 goto out; 3178 } 3179 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3180 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3181 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3182 error_fr(r, "parse"); 3183 goto out; 3184 } 3185 if (listen_port > 65535) { 3186 error_f("tcpip-forward for %s: bad port %u", 3187 listen_host, listen_port); 3188 goto out; 3189 } 3190 /* Record that connection to this host/port is permitted. */ 3191 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 3192 listen_host, NULL, (int)listen_port, downstream); 3193 listen_host = NULL; 3194 break; 3195 case SSH2_MSG_CHANNEL_CLOSE: 3196 if (have < 4) 3197 break; 3198 remote_id = PEEK_U32(cp); 3199 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3200 if (c->flags & CHAN_CLOSE_RCVD) 3201 channel_free(ssh, c); 3202 else 3203 c->flags |= CHAN_CLOSE_SENT; 3204 } 3205 break; 3206 } 3207 if (modified) { 3208 if ((r = sshpkt_start(ssh, type)) != 0 || 3209 (r = sshpkt_putb(ssh, modified)) != 0 || 3210 (r = sshpkt_send(ssh)) != 0) { 3211 error_fr(r, "send"); 3212 goto out; 3213 } 3214 } else { 3215 if ((r = sshpkt_start(ssh, type)) != 0 || 3216 (r = sshpkt_put(ssh, cp, have)) != 0 || 3217 (r = sshpkt_send(ssh)) != 0) { 3218 error_fr(r, "send"); 3219 goto out; 3220 } 3221 } 3222 ret = 0; 3223 out: 3224 free(ctype); 3225 free(listen_host); 3226 sshbuf_free(original); 3227 sshbuf_free(modified); 3228 return ret; 3229 } 3230 3231 /* 3232 * receive packets from upstream server and de-multiplex packets 3233 * to correct downstream: 3234 * implemented as a helper for channel input handlers, 3235 * replaces local (proxy) channel ID with downstream channel ID. 3236 */ 3237 int 3238 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3239 { 3240 struct sshbuf *b = NULL; 3241 Channel *downstream; 3242 const u_char *cp = NULL; 3243 size_t len; 3244 int r; 3245 3246 /* 3247 * When receiving packets from the peer we need to check whether we 3248 * need to forward the packets to the mux client. In this case we 3249 * restore the original channel id and keep track of CLOSE messages, 3250 * so we can cleanup the channel. 3251 */ 3252 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3253 return 0; 3254 if ((downstream = c->mux_ctx) == NULL) 3255 return 0; 3256 switch (type) { 3257 case SSH2_MSG_CHANNEL_CLOSE: 3258 case SSH2_MSG_CHANNEL_DATA: 3259 case SSH2_MSG_CHANNEL_EOF: 3260 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3261 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3262 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3263 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3264 case SSH2_MSG_CHANNEL_SUCCESS: 3265 case SSH2_MSG_CHANNEL_FAILURE: 3266 case SSH2_MSG_CHANNEL_REQUEST: 3267 break; 3268 default: 3269 debug2_f("channel %u: unsupported type %u", c->self, type); 3270 return 0; 3271 } 3272 if ((b = sshbuf_new()) == NULL) { 3273 error_f("alloc reply"); 3274 goto out; 3275 } 3276 /* get remaining payload (after id) */ 3277 cp = sshpkt_ptr(ssh, &len); 3278 if (cp == NULL) { 3279 error_f("no packet"); 3280 goto out; 3281 } 3282 /* translate id and send to muxclient */ 3283 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3284 (r = sshbuf_put_u8(b, type)) != 0 || 3285 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3286 (r = sshbuf_put(b, cp, len)) != 0 || 3287 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3288 error_fr(r, "compose muxclient"); 3289 goto out; 3290 } 3291 /* sshbuf_dump(b, stderr); */ 3292 if (ssh_packet_log_type(type)) 3293 debug3_f("channel %u: up->down: type %u", c->self, type); 3294 out: 3295 /* update state */ 3296 switch (type) { 3297 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3298 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3299 if (cp && len > 4) { 3300 c->remote_id = PEEK_U32(cp); 3301 c->have_remote_id = 1; 3302 } 3303 break; 3304 case SSH2_MSG_CHANNEL_CLOSE: 3305 if (c->flags & CHAN_CLOSE_SENT) 3306 channel_free(ssh, c); 3307 else 3308 c->flags |= CHAN_CLOSE_RCVD; 3309 break; 3310 } 3311 sshbuf_free(b); 3312 return 1; 3313 } 3314 3315 /* -- protocol input */ 3316 3317 /* Parse a channel ID from the current packet */ 3318 static int 3319 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3320 { 3321 u_int32_t id; 3322 int r; 3323 3324 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3325 error_r(r, "%s: parse id", where); 3326 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3327 } 3328 if (id > INT_MAX) { 3329 error_r(r, "%s: bad channel id %u", where, id); 3330 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3331 } 3332 return (int)id; 3333 } 3334 3335 /* Lookup a channel from an ID in the current packet */ 3336 static Channel * 3337 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3338 { 3339 int id = channel_parse_id(ssh, where, what); 3340 Channel *c; 3341 3342 if ((c = channel_lookup(ssh, id)) == NULL) { 3343 ssh_packet_disconnect(ssh, 3344 "%s packet referred to nonexistent channel %d", what, id); 3345 } 3346 return c; 3347 } 3348 3349 int 3350 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3351 { 3352 const u_char *data; 3353 size_t data_len, win_len; 3354 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3355 int r; 3356 3357 if (channel_proxy_upstream(c, type, seq, ssh)) 3358 return 0; 3359 3360 /* Ignore any data for non-open channels (might happen on close) */ 3361 if (c->type != SSH_CHANNEL_OPEN && 3362 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3363 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3364 c->type != SSH_CHANNEL_X11_OPEN) 3365 return 0; 3366 3367 /* Get the data. */ 3368 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3369 (r = sshpkt_get_end(ssh)) != 0) 3370 fatal_fr(r, "channel %i: get data", c->self); 3371 3372 win_len = data_len; 3373 if (c->datagram) 3374 win_len += 4; /* string length header */ 3375 3376 /* 3377 * The sending side reduces its window as it sends data, so we 3378 * must 'fake' consumption of the data in order to ensure that window 3379 * updates are sent back. Otherwise the connection might deadlock. 3380 */ 3381 if (c->ostate != CHAN_OUTPUT_OPEN) { 3382 c->local_window -= win_len; 3383 c->local_consumed += win_len; 3384 return 0; 3385 } 3386 3387 if (win_len > c->local_maxpacket) { 3388 logit("channel %d: rcvd big packet %zu, maxpack %u", 3389 c->self, win_len, c->local_maxpacket); 3390 return 0; 3391 } 3392 if (win_len > c->local_window) { 3393 logit("channel %d: rcvd too much data %zu, win %u", 3394 c->self, win_len, c->local_window); 3395 return 0; 3396 } 3397 c->local_window -= win_len; 3398 3399 if (c->datagram) { 3400 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3401 fatal_fr(r, "channel %i: append datagram", c->self); 3402 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3403 fatal_fr(r, "channel %i: append data", c->self); 3404 3405 return 0; 3406 } 3407 3408 int 3409 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3410 { 3411 const u_char *data; 3412 size_t data_len; 3413 u_int32_t tcode; 3414 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3415 int r; 3416 3417 if (channel_proxy_upstream(c, type, seq, ssh)) 3418 return 0; 3419 if (c->type != SSH_CHANNEL_OPEN) { 3420 logit("channel %d: ext data for non open", c->self); 3421 return 0; 3422 } 3423 if (c->flags & CHAN_EOF_RCVD) { 3424 if (ssh->compat & SSH_BUG_EXTEOF) 3425 debug("channel %d: accepting ext data after eof", 3426 c->self); 3427 else 3428 ssh_packet_disconnect(ssh, "Received extended_data " 3429 "after EOF on channel %d.", c->self); 3430 } 3431 3432 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3433 error_fr(r, "parse tcode"); 3434 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3435 } 3436 if (c->efd == -1 || 3437 c->extended_usage != CHAN_EXTENDED_WRITE || 3438 tcode != SSH2_EXTENDED_DATA_STDERR) { 3439 logit("channel %d: bad ext data", c->self); 3440 return 0; 3441 } 3442 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3443 (r = sshpkt_get_end(ssh)) != 0) { 3444 error_fr(r, "parse data"); 3445 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3446 } 3447 3448 if (data_len > c->local_window) { 3449 logit("channel %d: rcvd too much extended_data %zu, win %u", 3450 c->self, data_len, c->local_window); 3451 return 0; 3452 } 3453 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3454 /* XXX sshpkt_getb? */ 3455 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3456 error_fr(r, "append"); 3457 c->local_window -= data_len; 3458 return 0; 3459 } 3460 3461 int 3462 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3463 { 3464 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3465 int r; 3466 3467 if ((r = sshpkt_get_end(ssh)) != 0) { 3468 error_fr(r, "parse data"); 3469 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3470 } 3471 3472 if (channel_proxy_upstream(c, type, seq, ssh)) 3473 return 0; 3474 chan_rcvd_ieof(ssh, c); 3475 3476 /* XXX force input close */ 3477 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3478 debug("channel %d: FORCE input drain", c->self); 3479 c->istate = CHAN_INPUT_WAIT_DRAIN; 3480 if (sshbuf_len(c->input) == 0) 3481 chan_ibuf_empty(ssh, c); 3482 } 3483 return 0; 3484 } 3485 3486 int 3487 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3488 { 3489 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3490 int r; 3491 3492 if (channel_proxy_upstream(c, type, seq, ssh)) 3493 return 0; 3494 if ((r = sshpkt_get_end(ssh)) != 0) { 3495 error_fr(r, "parse data"); 3496 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3497 } 3498 chan_rcvd_oclose(ssh, c); 3499 return 0; 3500 } 3501 3502 int 3503 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3504 { 3505 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3506 u_int32_t remote_window, remote_maxpacket; 3507 int r; 3508 3509 if (channel_proxy_upstream(c, type, seq, ssh)) 3510 return 0; 3511 if (c->type != SSH_CHANNEL_OPENING) 3512 ssh_packet_disconnect(ssh, "Received open confirmation for " 3513 "non-opening channel %d.", c->self); 3514 /* 3515 * Record the remote channel number and mark that the channel 3516 * is now open. 3517 */ 3518 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3519 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3520 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3521 (r = sshpkt_get_end(ssh)) != 0) { 3522 error_fr(r, "window/maxpacket"); 3523 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3524 } 3525 3526 c->have_remote_id = 1; 3527 c->remote_window = remote_window; 3528 c->remote_maxpacket = remote_maxpacket; 3529 c->type = SSH_CHANNEL_OPEN; 3530 if (c->open_confirm) { 3531 debug2_f("channel %d: callback start", c->self); 3532 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3533 debug2_f("channel %d: callback done", c->self); 3534 } 3535 c->lastused = monotime(); 3536 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3537 c->remote_window, c->remote_maxpacket); 3538 return 0; 3539 } 3540 3541 static char * 3542 reason2txt(int reason) 3543 { 3544 switch (reason) { 3545 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3546 return "administratively prohibited"; 3547 case SSH2_OPEN_CONNECT_FAILED: 3548 return "connect failed"; 3549 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3550 return "unknown channel type"; 3551 case SSH2_OPEN_RESOURCE_SHORTAGE: 3552 return "resource shortage"; 3553 } 3554 return "unknown reason"; 3555 } 3556 3557 int 3558 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3559 { 3560 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3561 u_int32_t reason; 3562 char *msg = NULL; 3563 int r; 3564 3565 if (channel_proxy_upstream(c, type, seq, ssh)) 3566 return 0; 3567 if (c->type != SSH_CHANNEL_OPENING) 3568 ssh_packet_disconnect(ssh, "Received open failure for " 3569 "non-opening channel %d.", c->self); 3570 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3571 error_fr(r, "parse reason"); 3572 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3573 } 3574 /* skip language */ 3575 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3576 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3577 (r = sshpkt_get_end(ssh)) != 0) { 3578 error_fr(r, "parse msg/lang"); 3579 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3580 } 3581 logit("channel %d: open failed: %s%s%s", c->self, 3582 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3583 free(msg); 3584 if (c->open_confirm) { 3585 debug2_f("channel %d: callback start", c->self); 3586 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3587 debug2_f("channel %d: callback done", c->self); 3588 } 3589 /* Schedule the channel for cleanup/deletion. */ 3590 chan_mark_dead(ssh, c); 3591 return 0; 3592 } 3593 3594 int 3595 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3596 { 3597 int id = channel_parse_id(ssh, __func__, "window adjust"); 3598 Channel *c; 3599 u_int32_t adjust; 3600 u_int new_rwin; 3601 int r; 3602 3603 if ((c = channel_lookup(ssh, id)) == NULL) { 3604 logit("Received window adjust for non-open channel %d.", id); 3605 return 0; 3606 } 3607 3608 if (channel_proxy_upstream(c, type, seq, ssh)) 3609 return 0; 3610 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3611 (r = sshpkt_get_end(ssh)) != 0) { 3612 error_fr(r, "parse adjust"); 3613 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3614 } 3615 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3616 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3617 fatal("channel %d: adjust %u overflows remote window %u", 3618 c->self, adjust, c->remote_window); 3619 } 3620 c->remote_window = new_rwin; 3621 return 0; 3622 } 3623 3624 int 3625 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3626 { 3627 int id = channel_parse_id(ssh, __func__, "status confirm"); 3628 Channel *c; 3629 struct channel_confirm *cc; 3630 3631 /* Reset keepalive timeout */ 3632 ssh_packet_set_alive_timeouts(ssh, 0); 3633 3634 debug2_f("type %d id %d", type, id); 3635 3636 if ((c = channel_lookup(ssh, id)) == NULL) { 3637 logit_f("%d: unknown", id); 3638 return 0; 3639 } 3640 if (channel_proxy_upstream(c, type, seq, ssh)) 3641 return 0; 3642 if (sshpkt_get_end(ssh) != 0) 3643 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3644 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3645 return 0; 3646 cc->cb(ssh, type, c, cc->ctx); 3647 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3648 freezero(cc, sizeof(*cc)); 3649 return 0; 3650 } 3651 3652 /* -- tcp forwarding */ 3653 3654 void 3655 channel_set_af(struct ssh *ssh, int af) 3656 { 3657 ssh->chanctxt->IPv4or6 = af; 3658 } 3659 3660 3661 /* 3662 * Determine whether or not a port forward listens to loopback, the 3663 * specified address or wildcard. On the client, a specified bind 3664 * address will always override gateway_ports. On the server, a 3665 * gateway_ports of 1 (``yes'') will override the client's specification 3666 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3667 * will bind to whatever address the client asked for. 3668 * 3669 * Special-case listen_addrs are: 3670 * 3671 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3672 * "" (empty string), "*" -> wildcard v4/v6 3673 * "localhost" -> loopback v4/v6 3674 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3675 */ 3676 static const char * 3677 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3678 int is_client, struct ForwardOptions *fwd_opts) 3679 { 3680 const char *addr = NULL; 3681 int wildcard = 0; 3682 3683 if (listen_addr == NULL) { 3684 /* No address specified: default to gateway_ports setting */ 3685 if (fwd_opts->gateway_ports) 3686 wildcard = 1; 3687 } else if (fwd_opts->gateway_ports || is_client) { 3688 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3689 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3690 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3691 (!is_client && fwd_opts->gateway_ports == 1)) { 3692 wildcard = 1; 3693 /* 3694 * Notify client if they requested a specific listen 3695 * address and it was overridden. 3696 */ 3697 if (*listen_addr != '\0' && 3698 strcmp(listen_addr, "0.0.0.0") != 0 && 3699 strcmp(listen_addr, "*") != 0) { 3700 ssh_packet_send_debug(ssh, 3701 "Forwarding listen address " 3702 "\"%s\" overridden by server " 3703 "GatewayPorts", listen_addr); 3704 } 3705 } else if (strcmp(listen_addr, "localhost") != 0 || 3706 strcmp(listen_addr, "127.0.0.1") == 0 || 3707 strcmp(listen_addr, "::1") == 0) { 3708 /* 3709 * Accept explicit localhost address when 3710 * GatewayPorts=yes. The "localhost" hostname is 3711 * deliberately skipped here so it will listen on all 3712 * available local address families. 3713 */ 3714 addr = listen_addr; 3715 } 3716 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3717 strcmp(listen_addr, "::1") == 0) { 3718 /* 3719 * If a specific IPv4/IPv6 localhost address has been 3720 * requested then accept it even if gateway_ports is in 3721 * effect. This allows the client to prefer IPv4 or IPv6. 3722 */ 3723 addr = listen_addr; 3724 } 3725 if (wildcardp != NULL) 3726 *wildcardp = wildcard; 3727 return addr; 3728 } 3729 3730 static int 3731 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3732 struct Forward *fwd, int *allocated_listen_port, 3733 struct ForwardOptions *fwd_opts) 3734 { 3735 Channel *c; 3736 int sock, r, success = 0, wildcard = 0, is_client; 3737 struct addrinfo hints, *ai, *aitop; 3738 const char *host, *addr; 3739 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3740 in_port_t *lport_p; 3741 3742 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3743 3744 if (is_client && fwd->connect_path != NULL) { 3745 host = fwd->connect_path; 3746 } else { 3747 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3748 fwd->listen_host : fwd->connect_host; 3749 if (host == NULL) { 3750 error("No forward host name."); 3751 return 0; 3752 } 3753 if (strlen(host) >= NI_MAXHOST) { 3754 error("Forward host name too long."); 3755 return 0; 3756 } 3757 } 3758 3759 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3760 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3761 is_client, fwd_opts); 3762 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3763 (addr == NULL) ? "NULL" : addr); 3764 3765 /* 3766 * getaddrinfo returns a loopback address if the hostname is 3767 * set to NULL and hints.ai_flags is not AI_PASSIVE 3768 */ 3769 memset(&hints, 0, sizeof(hints)); 3770 hints.ai_family = ssh->chanctxt->IPv4or6; 3771 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3772 hints.ai_socktype = SOCK_STREAM; 3773 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3774 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3775 if (addr == NULL) { 3776 /* This really shouldn't happen */ 3777 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3778 ssh_gai_strerror(r)); 3779 } else { 3780 error_f("getaddrinfo(%.64s): %s", addr, 3781 ssh_gai_strerror(r)); 3782 } 3783 return 0; 3784 } 3785 if (allocated_listen_port != NULL) 3786 *allocated_listen_port = 0; 3787 for (ai = aitop; ai; ai = ai->ai_next) { 3788 switch (ai->ai_family) { 3789 case AF_INET: 3790 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3791 sin_port; 3792 break; 3793 case AF_INET6: 3794 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3795 sin6_port; 3796 break; 3797 default: 3798 continue; 3799 } 3800 /* 3801 * If allocating a port for -R forwards, then use the 3802 * same port for all address families. 3803 */ 3804 if (type == SSH_CHANNEL_RPORT_LISTENER && 3805 fwd->listen_port == 0 && allocated_listen_port != NULL && 3806 *allocated_listen_port > 0) 3807 *lport_p = htons(*allocated_listen_port); 3808 3809 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3810 strport, sizeof(strport), 3811 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3812 error_f("getnameinfo failed"); 3813 continue; 3814 } 3815 /* Create a port to listen for the host. */ 3816 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3817 if (sock == -1) { 3818 /* this is no error since kernel may not support ipv6 */ 3819 verbose("socket [%s]:%s: %.100s", ntop, strport, 3820 strerror(errno)); 3821 continue; 3822 } 3823 3824 set_reuseaddr(sock); 3825 if (ai->ai_family == AF_INET6) 3826 sock_set_v6only(sock); 3827 3828 debug("Local forwarding listening on %s port %s.", 3829 ntop, strport); 3830 3831 /* Bind the socket to the address. */ 3832 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3833 /* 3834 * address can be in if use ipv6 address is 3835 * already bound 3836 */ 3837 if (!ai->ai_next) 3838 error("bind [%s]:%s: %.100s", 3839 ntop, strport, strerror(errno)); 3840 else 3841 verbose("bind [%s]:%s: %.100s", 3842 ntop, strport, strerror(errno)); 3843 3844 close(sock); 3845 continue; 3846 } 3847 /* Start listening for connections on the socket. */ 3848 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3849 error("listen [%s]:%s: %.100s", ntop, strport, 3850 strerror(errno)); 3851 close(sock); 3852 continue; 3853 } 3854 3855 /* 3856 * fwd->listen_port == 0 requests a dynamically allocated port - 3857 * record what we got. 3858 */ 3859 if (type == SSH_CHANNEL_RPORT_LISTENER && 3860 fwd->listen_port == 0 && 3861 allocated_listen_port != NULL && 3862 *allocated_listen_port == 0) { 3863 *allocated_listen_port = get_local_port(sock); 3864 debug("Allocated listen port %d", 3865 *allocated_listen_port); 3866 } 3867 3868 /* Allocate a channel number for the socket. */ 3869 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3870 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3871 0, "port listener", 1); 3872 c->path = xstrdup(host); 3873 c->host_port = fwd->connect_port; 3874 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3875 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3876 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3877 c->listening_port = *allocated_listen_port; 3878 else 3879 c->listening_port = fwd->listen_port; 3880 success = 1; 3881 } 3882 if (success == 0) 3883 error_f("cannot listen to port: %d", fwd->listen_port); 3884 freeaddrinfo(aitop); 3885 return success; 3886 } 3887 3888 static int 3889 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3890 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3891 { 3892 struct sockaddr_un sunaddr; 3893 const char *path; 3894 Channel *c; 3895 int port, sock; 3896 mode_t omask; 3897 3898 switch (type) { 3899 case SSH_CHANNEL_UNIX_LISTENER: 3900 if (fwd->connect_path != NULL) { 3901 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3902 error("Local connecting path too long: %s", 3903 fwd->connect_path); 3904 return 0; 3905 } 3906 path = fwd->connect_path; 3907 port = PORT_STREAMLOCAL; 3908 } else { 3909 if (fwd->connect_host == NULL) { 3910 error("No forward host name."); 3911 return 0; 3912 } 3913 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3914 error("Forward host name too long."); 3915 return 0; 3916 } 3917 path = fwd->connect_host; 3918 port = fwd->connect_port; 3919 } 3920 break; 3921 case SSH_CHANNEL_RUNIX_LISTENER: 3922 path = fwd->listen_path; 3923 port = PORT_STREAMLOCAL; 3924 break; 3925 default: 3926 error_f("unexpected channel type %d", type); 3927 return 0; 3928 } 3929 3930 if (fwd->listen_path == NULL) { 3931 error("No forward path name."); 3932 return 0; 3933 } 3934 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3935 error("Local listening path too long: %s", fwd->listen_path); 3936 return 0; 3937 } 3938 3939 debug3_f("type %d path %s", type, fwd->listen_path); 3940 3941 /* Start a Unix domain listener. */ 3942 omask = umask(fwd_opts->streamlocal_bind_mask); 3943 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3944 fwd_opts->streamlocal_bind_unlink); 3945 umask(omask); 3946 if (sock < 0) 3947 return 0; 3948 3949 debug("Local forwarding listening on path %s.", fwd->listen_path); 3950 3951 /* Allocate a channel number for the socket. */ 3952 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 3953 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3954 0, "unix listener", 1); 3955 c->path = xstrdup(path); 3956 c->host_port = port; 3957 c->listening_port = PORT_STREAMLOCAL; 3958 c->listening_addr = xstrdup(fwd->listen_path); 3959 return 1; 3960 } 3961 3962 static int 3963 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3964 const char *host, u_short port) 3965 { 3966 u_int i; 3967 int found = 0; 3968 3969 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3970 Channel *c = ssh->chanctxt->channels[i]; 3971 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3972 continue; 3973 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3974 debug2_f("close channel %d", i); 3975 channel_free(ssh, c); 3976 found = 1; 3977 } 3978 } 3979 3980 return found; 3981 } 3982 3983 static int 3984 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3985 { 3986 u_int i; 3987 int found = 0; 3988 3989 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3990 Channel *c = ssh->chanctxt->channels[i]; 3991 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3992 continue; 3993 if (c->path == NULL) 3994 continue; 3995 if (strcmp(c->path, path) == 0) { 3996 debug2_f("close channel %d", i); 3997 channel_free(ssh, c); 3998 found = 1; 3999 } 4000 } 4001 4002 return found; 4003 } 4004 4005 int 4006 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4007 { 4008 if (fwd->listen_path != NULL) { 4009 return channel_cancel_rport_listener_streamlocal(ssh, 4010 fwd->listen_path); 4011 } else { 4012 return channel_cancel_rport_listener_tcpip(ssh, 4013 fwd->listen_host, fwd->listen_port); 4014 } 4015 } 4016 4017 static int 4018 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4019 const char *lhost, u_short lport, int cport, 4020 struct ForwardOptions *fwd_opts) 4021 { 4022 u_int i; 4023 int found = 0; 4024 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4025 4026 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4027 Channel *c = ssh->chanctxt->channels[i]; 4028 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4029 continue; 4030 if (c->listening_port != lport) 4031 continue; 4032 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4033 /* skip dynamic forwardings */ 4034 if (c->host_port == 0) 4035 continue; 4036 } else { 4037 if (c->host_port != cport) 4038 continue; 4039 } 4040 if ((c->listening_addr == NULL && addr != NULL) || 4041 (c->listening_addr != NULL && addr == NULL)) 4042 continue; 4043 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4044 debug2_f("close channel %d", i); 4045 channel_free(ssh, c); 4046 found = 1; 4047 } 4048 } 4049 4050 return found; 4051 } 4052 4053 static int 4054 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4055 { 4056 u_int i; 4057 int found = 0; 4058 4059 if (path == NULL) { 4060 error_f("no path specified."); 4061 return 0; 4062 } 4063 4064 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4065 Channel *c = ssh->chanctxt->channels[i]; 4066 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4067 continue; 4068 if (c->listening_addr == NULL) 4069 continue; 4070 if (strcmp(c->listening_addr, path) == 0) { 4071 debug2_f("close channel %d", i); 4072 channel_free(ssh, c); 4073 found = 1; 4074 } 4075 } 4076 4077 return found; 4078 } 4079 4080 int 4081 channel_cancel_lport_listener(struct ssh *ssh, 4082 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4083 { 4084 if (fwd->listen_path != NULL) { 4085 return channel_cancel_lport_listener_streamlocal(ssh, 4086 fwd->listen_path); 4087 } else { 4088 return channel_cancel_lport_listener_tcpip(ssh, 4089 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4090 } 4091 } 4092 4093 /* protocol local port fwd, used by ssh */ 4094 int 4095 channel_setup_local_fwd_listener(struct ssh *ssh, 4096 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4097 { 4098 if (fwd->listen_path != NULL) { 4099 return channel_setup_fwd_listener_streamlocal(ssh, 4100 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4101 } else { 4102 return channel_setup_fwd_listener_tcpip(ssh, 4103 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4104 } 4105 } 4106 4107 /* Matches a remote forwarding permission against a requested forwarding */ 4108 static int 4109 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4110 { 4111 int ret; 4112 char *lhost; 4113 4114 /* XXX add ACLs for streamlocal */ 4115 if (fwd->listen_path != NULL) 4116 return 1; 4117 4118 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4119 return 0; 4120 4121 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4122 allowed_open->listen_port != fwd->listen_port) 4123 return 0; 4124 4125 /* Match hostnames case-insensitively */ 4126 lhost = xstrdup(fwd->listen_host); 4127 lowercase(lhost); 4128 ret = match_pattern(lhost, allowed_open->listen_host); 4129 free(lhost); 4130 4131 return ret; 4132 } 4133 4134 /* Checks whether a requested remote forwarding is permitted */ 4135 static int 4136 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4137 { 4138 struct ssh_channels *sc = ssh->chanctxt; 4139 struct permission_set *pset = &sc->remote_perms; 4140 u_int i, permit, permit_adm = 1; 4141 struct permission *perm; 4142 4143 /* XXX apply GatewayPorts override before checking? */ 4144 4145 permit = pset->all_permitted; 4146 if (!permit) { 4147 for (i = 0; i < pset->num_permitted_user; i++) { 4148 perm = &pset->permitted_user[i]; 4149 if (remote_open_match(perm, fwd)) { 4150 permit = 1; 4151 break; 4152 } 4153 } 4154 } 4155 4156 if (pset->num_permitted_admin > 0) { 4157 permit_adm = 0; 4158 for (i = 0; i < pset->num_permitted_admin; i++) { 4159 perm = &pset->permitted_admin[i]; 4160 if (remote_open_match(perm, fwd)) { 4161 permit_adm = 1; 4162 break; 4163 } 4164 } 4165 } 4166 4167 return permit && permit_adm; 4168 } 4169 4170 /* protocol v2 remote port fwd, used by sshd */ 4171 int 4172 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4173 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4174 { 4175 if (!check_rfwd_permission(ssh, fwd)) { 4176 ssh_packet_send_debug(ssh, "port forwarding refused"); 4177 if (fwd->listen_path != NULL) 4178 /* XXX always allowed, see remote_open_match() */ 4179 logit("Received request from %.100s port %d to " 4180 "remote forward to path \"%.100s\", " 4181 "but the request was denied.", 4182 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4183 fwd->listen_path); 4184 else if(fwd->listen_host != NULL) 4185 logit("Received request from %.100s port %d to " 4186 "remote forward to host %.100s port %d, " 4187 "but the request was denied.", 4188 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4189 fwd->listen_host, fwd->listen_port ); 4190 else 4191 logit("Received request from %.100s port %d to remote " 4192 "forward, but the request was denied.", 4193 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4194 return 0; 4195 } 4196 if (fwd->listen_path != NULL) { 4197 return channel_setup_fwd_listener_streamlocal(ssh, 4198 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4199 } else { 4200 return channel_setup_fwd_listener_tcpip(ssh, 4201 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4202 fwd_opts); 4203 } 4204 } 4205 4206 /* 4207 * Translate the requested rfwd listen host to something usable for 4208 * this server. 4209 */ 4210 static const char * 4211 channel_rfwd_bind_host(const char *listen_host) 4212 { 4213 if (listen_host == NULL) { 4214 return "localhost"; 4215 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4216 return ""; 4217 } else 4218 return listen_host; 4219 } 4220 4221 /* 4222 * Initiate forwarding of connections to port "port" on remote host through 4223 * the secure channel to host:port from local side. 4224 * Returns handle (index) for updating the dynamic listen port with 4225 * channel_update_permission(). 4226 */ 4227 int 4228 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4229 { 4230 int r, success = 0, idx = -1; 4231 const char *host_to_connect, *listen_host, *listen_path; 4232 int port_to_connect, listen_port; 4233 4234 /* Send the forward request to the remote side. */ 4235 if (fwd->listen_path != NULL) { 4236 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4237 (r = sshpkt_put_cstring(ssh, 4238 "streamlocal-forward@openssh.com")) != 0 || 4239 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4240 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4241 (r = sshpkt_send(ssh)) != 0 || 4242 (r = ssh_packet_write_wait(ssh)) != 0) 4243 fatal_fr(r, "request streamlocal"); 4244 } else { 4245 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4246 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4247 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4248 (r = sshpkt_put_cstring(ssh, 4249 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4250 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4251 (r = sshpkt_send(ssh)) != 0 || 4252 (r = ssh_packet_write_wait(ssh)) != 0) 4253 fatal_fr(r, "request tcpip-forward"); 4254 } 4255 /* Assume that server accepts the request */ 4256 success = 1; 4257 if (success) { 4258 /* Record that connection to this host/port is permitted. */ 4259 host_to_connect = listen_host = listen_path = NULL; 4260 port_to_connect = listen_port = 0; 4261 if (fwd->connect_path != NULL) { 4262 host_to_connect = fwd->connect_path; 4263 port_to_connect = PORT_STREAMLOCAL; 4264 } else { 4265 host_to_connect = fwd->connect_host; 4266 port_to_connect = fwd->connect_port; 4267 } 4268 if (fwd->listen_path != NULL) { 4269 listen_path = fwd->listen_path; 4270 listen_port = PORT_STREAMLOCAL; 4271 } else { 4272 listen_host = fwd->listen_host; 4273 listen_port = fwd->listen_port; 4274 } 4275 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4276 host_to_connect, port_to_connect, 4277 listen_host, listen_path, listen_port, NULL); 4278 } 4279 return idx; 4280 } 4281 4282 static int 4283 open_match(struct permission *allowed_open, const char *requestedhost, 4284 int requestedport) 4285 { 4286 if (allowed_open->host_to_connect == NULL) 4287 return 0; 4288 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4289 allowed_open->port_to_connect != requestedport) 4290 return 0; 4291 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4292 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4293 return 0; 4294 return 1; 4295 } 4296 4297 /* 4298 * Note that in the listen host/port case 4299 * we don't support FWD_PERMIT_ANY_PORT and 4300 * need to translate between the configured-host (listen_host) 4301 * and what we've sent to the remote server (channel_rfwd_bind_host) 4302 */ 4303 static int 4304 open_listen_match_tcpip(struct permission *allowed_open, 4305 const char *requestedhost, u_short requestedport, int translate) 4306 { 4307 const char *allowed_host; 4308 4309 if (allowed_open->host_to_connect == NULL) 4310 return 0; 4311 if (allowed_open->listen_port != requestedport) 4312 return 0; 4313 if (!translate && allowed_open->listen_host == NULL && 4314 requestedhost == NULL) 4315 return 1; 4316 allowed_host = translate ? 4317 channel_rfwd_bind_host(allowed_open->listen_host) : 4318 allowed_open->listen_host; 4319 if (allowed_host == NULL || requestedhost == NULL || 4320 strcmp(allowed_host, requestedhost) != 0) 4321 return 0; 4322 return 1; 4323 } 4324 4325 static int 4326 open_listen_match_streamlocal(struct permission *allowed_open, 4327 const char *requestedpath) 4328 { 4329 if (allowed_open->host_to_connect == NULL) 4330 return 0; 4331 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4332 return 0; 4333 if (allowed_open->listen_path == NULL || 4334 strcmp(allowed_open->listen_path, requestedpath) != 0) 4335 return 0; 4336 return 1; 4337 } 4338 4339 /* 4340 * Request cancellation of remote forwarding of connection host:port from 4341 * local side. 4342 */ 4343 static int 4344 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4345 const char *host, u_short port) 4346 { 4347 struct ssh_channels *sc = ssh->chanctxt; 4348 struct permission_set *pset = &sc->local_perms; 4349 int r; 4350 u_int i; 4351 struct permission *perm = NULL; 4352 4353 for (i = 0; i < pset->num_permitted_user; i++) { 4354 perm = &pset->permitted_user[i]; 4355 if (open_listen_match_tcpip(perm, host, port, 0)) 4356 break; 4357 perm = NULL; 4358 } 4359 if (perm == NULL) { 4360 debug_f("requested forward not found"); 4361 return -1; 4362 } 4363 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4364 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4365 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4366 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4367 (r = sshpkt_put_u32(ssh, port)) != 0 || 4368 (r = sshpkt_send(ssh)) != 0) 4369 fatal_fr(r, "send cancel"); 4370 4371 fwd_perm_clear(perm); /* unregister */ 4372 4373 return 0; 4374 } 4375 4376 /* 4377 * Request cancellation of remote forwarding of Unix domain socket 4378 * path from local side. 4379 */ 4380 static int 4381 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4382 { 4383 struct ssh_channels *sc = ssh->chanctxt; 4384 struct permission_set *pset = &sc->local_perms; 4385 int r; 4386 u_int i; 4387 struct permission *perm = NULL; 4388 4389 for (i = 0; i < pset->num_permitted_user; i++) { 4390 perm = &pset->permitted_user[i]; 4391 if (open_listen_match_streamlocal(perm, path)) 4392 break; 4393 perm = NULL; 4394 } 4395 if (perm == NULL) { 4396 debug_f("requested forward not found"); 4397 return -1; 4398 } 4399 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4400 (r = sshpkt_put_cstring(ssh, 4401 "cancel-streamlocal-forward@openssh.com")) != 0 || 4402 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4403 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4404 (r = sshpkt_send(ssh)) != 0) 4405 fatal_fr(r, "send cancel"); 4406 4407 fwd_perm_clear(perm); /* unregister */ 4408 4409 return 0; 4410 } 4411 4412 /* 4413 * Request cancellation of remote forwarding of a connection from local side. 4414 */ 4415 int 4416 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4417 { 4418 if (fwd->listen_path != NULL) { 4419 return channel_request_rforward_cancel_streamlocal(ssh, 4420 fwd->listen_path); 4421 } else { 4422 return channel_request_rforward_cancel_tcpip(ssh, 4423 fwd->listen_host, 4424 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4425 } 4426 } 4427 4428 /* 4429 * Permits opening to any host/port if permitted_user[] is empty. This is 4430 * usually called by the server, because the user could connect to any port 4431 * anyway, and the server has no way to know but to trust the client anyway. 4432 */ 4433 void 4434 channel_permit_all(struct ssh *ssh, int where) 4435 { 4436 struct permission_set *pset = permission_set_get(ssh, where); 4437 4438 if (pset->num_permitted_user == 0) 4439 pset->all_permitted = 1; 4440 } 4441 4442 /* 4443 * Permit the specified host/port for forwarding. 4444 */ 4445 void 4446 channel_add_permission(struct ssh *ssh, int who, int where, 4447 char *host, int port) 4448 { 4449 int local = where == FORWARD_LOCAL; 4450 struct permission_set *pset = permission_set_get(ssh, where); 4451 4452 debug("allow %s forwarding to host %s port %d", 4453 fwd_ident(who, where), host, port); 4454 /* 4455 * Remote forwards set listen_host/port, local forwards set 4456 * host/port_to_connect. 4457 */ 4458 permission_set_add(ssh, who, where, 4459 local ? host : 0, local ? port : 0, 4460 local ? NULL : host, NULL, local ? 0 : port, NULL); 4461 pset->all_permitted = 0; 4462 } 4463 4464 /* 4465 * Administratively disable forwarding. 4466 */ 4467 void 4468 channel_disable_admin(struct ssh *ssh, int where) 4469 { 4470 channel_clear_permission(ssh, FORWARD_ADM, where); 4471 permission_set_add(ssh, FORWARD_ADM, where, 4472 NULL, 0, NULL, NULL, 0, NULL); 4473 } 4474 4475 /* 4476 * Clear a list of permitted opens. 4477 */ 4478 void 4479 channel_clear_permission(struct ssh *ssh, int who, int where) 4480 { 4481 struct permission **permp; 4482 u_int *npermp; 4483 4484 permission_set_get_array(ssh, who, where, &permp, &npermp); 4485 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4486 *npermp = 0; 4487 } 4488 4489 /* 4490 * Update the listen port for a dynamic remote forward, after 4491 * the actual 'newport' has been allocated. If 'newport' < 0 is 4492 * passed then they entry will be invalidated. 4493 */ 4494 void 4495 channel_update_permission(struct ssh *ssh, int idx, int newport) 4496 { 4497 struct permission_set *pset = &ssh->chanctxt->local_perms; 4498 4499 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4500 debug_f("index out of range: %d num_permitted_user %d", 4501 idx, pset->num_permitted_user); 4502 return; 4503 } 4504 debug("%s allowed port %d for forwarding to host %s port %d", 4505 newport > 0 ? "Updating" : "Removing", 4506 newport, 4507 pset->permitted_user[idx].host_to_connect, 4508 pset->permitted_user[idx].port_to_connect); 4509 if (newport <= 0) 4510 fwd_perm_clear(&pset->permitted_user[idx]); 4511 else { 4512 pset->permitted_user[idx].listen_port = 4513 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4514 } 4515 } 4516 4517 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4518 int 4519 permitopen_port(const char *p) 4520 { 4521 int port; 4522 4523 if (strcmp(p, "*") == 0) 4524 return FWD_PERMIT_ANY_PORT; 4525 if ((port = a2port(p)) > 0) 4526 return port; 4527 return -1; 4528 } 4529 4530 /* Try to start non-blocking connect to next host in cctx list */ 4531 static int 4532 connect_next(struct channel_connect *cctx) 4533 { 4534 int sock, saved_errno; 4535 struct sockaddr_un *sunaddr; 4536 char ntop[NI_MAXHOST]; 4537 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4538 4539 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4540 switch (cctx->ai->ai_family) { 4541 case AF_UNIX: 4542 /* unix:pathname instead of host:port */ 4543 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4544 strlcpy(ntop, "unix", sizeof(ntop)); 4545 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4546 break; 4547 case AF_INET: 4548 case AF_INET6: 4549 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4550 ntop, sizeof(ntop), strport, sizeof(strport), 4551 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4552 error_f("getnameinfo failed"); 4553 continue; 4554 } 4555 break; 4556 default: 4557 continue; 4558 } 4559 debug_f("start for host %.100s ([%.100s]:%s)", 4560 cctx->host, ntop, strport); 4561 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4562 cctx->ai->ai_protocol)) == -1) { 4563 if (cctx->ai->ai_next == NULL) 4564 error("socket: %.100s", strerror(errno)); 4565 else 4566 verbose("socket: %.100s", strerror(errno)); 4567 continue; 4568 } 4569 if (set_nonblock(sock) == -1) 4570 fatal_f("set_nonblock(%d)", sock); 4571 if (connect(sock, cctx->ai->ai_addr, 4572 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4573 debug_f("host %.100s ([%.100s]:%s): %.100s", 4574 cctx->host, ntop, strport, strerror(errno)); 4575 saved_errno = errno; 4576 close(sock); 4577 errno = saved_errno; 4578 continue; /* fail -- try next */ 4579 } 4580 if (cctx->ai->ai_family != AF_UNIX) 4581 set_nodelay(sock); 4582 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4583 cctx->host, ntop, strport, sock); 4584 cctx->ai = cctx->ai->ai_next; 4585 return sock; 4586 } 4587 return -1; 4588 } 4589 4590 static void 4591 channel_connect_ctx_free(struct channel_connect *cctx) 4592 { 4593 free(cctx->host); 4594 if (cctx->aitop) { 4595 if (cctx->aitop->ai_family == AF_UNIX) 4596 free(cctx->aitop); 4597 else 4598 freeaddrinfo(cctx->aitop); 4599 } 4600 memset(cctx, 0, sizeof(*cctx)); 4601 } 4602 4603 /* 4604 * Return connecting socket to remote host:port or local socket path, 4605 * passing back the failure reason if appropriate. 4606 */ 4607 static int 4608 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4609 char *ctype, char *rname, struct channel_connect *cctx, 4610 int *reason, const char **errmsg) 4611 { 4612 struct addrinfo hints; 4613 int gaierr; 4614 int sock = -1; 4615 char strport[NI_MAXSERV]; 4616 4617 if (port == PORT_STREAMLOCAL) { 4618 struct sockaddr_un *sunaddr; 4619 struct addrinfo *ai; 4620 4621 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4622 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4623 return -1; 4624 } 4625 4626 /* 4627 * Fake up a struct addrinfo for AF_UNIX connections. 4628 * channel_connect_ctx_free() must check ai_family 4629 * and use free() not freeaddirinfo() for AF_UNIX. 4630 */ 4631 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4632 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4633 ai->ai_addr = (struct sockaddr *)(ai + 1); 4634 ai->ai_addrlen = sizeof(*sunaddr); 4635 ai->ai_family = AF_UNIX; 4636 ai->ai_socktype = socktype; 4637 ai->ai_protocol = PF_UNSPEC; 4638 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4639 sunaddr->sun_family = AF_UNIX; 4640 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4641 cctx->aitop = ai; 4642 } else { 4643 memset(&hints, 0, sizeof(hints)); 4644 hints.ai_family = ssh->chanctxt->IPv4or6; 4645 hints.ai_socktype = socktype; 4646 snprintf(strport, sizeof strport, "%d", port); 4647 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4648 != 0) { 4649 if (errmsg != NULL) 4650 *errmsg = ssh_gai_strerror(gaierr); 4651 if (reason != NULL) 4652 *reason = SSH2_OPEN_CONNECT_FAILED; 4653 error("connect_to %.100s: unknown host (%s)", name, 4654 ssh_gai_strerror(gaierr)); 4655 return -1; 4656 } 4657 } 4658 4659 cctx->host = xstrdup(name); 4660 cctx->port = port; 4661 cctx->ai = cctx->aitop; 4662 4663 if ((sock = connect_next(cctx)) == -1) { 4664 error("connect to %.100s port %d failed: %s", 4665 name, port, strerror(errno)); 4666 return -1; 4667 } 4668 4669 return sock; 4670 } 4671 4672 /* Return CONNECTING channel to remote host:port or local socket path */ 4673 static Channel * 4674 connect_to(struct ssh *ssh, const char *host, int port, 4675 char *ctype, char *rname) 4676 { 4677 struct channel_connect cctx; 4678 Channel *c; 4679 int sock; 4680 4681 memset(&cctx, 0, sizeof(cctx)); 4682 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4683 &cctx, NULL, NULL); 4684 if (sock == -1) { 4685 channel_connect_ctx_free(&cctx); 4686 return NULL; 4687 } 4688 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4689 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4690 c->host_port = port; 4691 c->path = xstrdup(host); 4692 c->connect_ctx = cctx; 4693 4694 return c; 4695 } 4696 4697 /* 4698 * returns either the newly connected channel or the downstream channel 4699 * that needs to deal with this connection. 4700 */ 4701 Channel * 4702 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4703 u_short listen_port, char *ctype, char *rname) 4704 { 4705 struct ssh_channels *sc = ssh->chanctxt; 4706 struct permission_set *pset = &sc->local_perms; 4707 u_int i; 4708 struct permission *perm; 4709 4710 for (i = 0; i < pset->num_permitted_user; i++) { 4711 perm = &pset->permitted_user[i]; 4712 if (open_listen_match_tcpip(perm, 4713 listen_host, listen_port, 1)) { 4714 if (perm->downstream) 4715 return perm->downstream; 4716 if (perm->port_to_connect == 0) 4717 return rdynamic_connect_prepare(ssh, 4718 ctype, rname); 4719 return connect_to(ssh, 4720 perm->host_to_connect, perm->port_to_connect, 4721 ctype, rname); 4722 } 4723 } 4724 error("WARNING: Server requests forwarding for unknown listen_port %d", 4725 listen_port); 4726 return NULL; 4727 } 4728 4729 Channel * 4730 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4731 char *ctype, char *rname) 4732 { 4733 struct ssh_channels *sc = ssh->chanctxt; 4734 struct permission_set *pset = &sc->local_perms; 4735 u_int i; 4736 struct permission *perm; 4737 4738 for (i = 0; i < pset->num_permitted_user; i++) { 4739 perm = &pset->permitted_user[i]; 4740 if (open_listen_match_streamlocal(perm, path)) { 4741 return connect_to(ssh, 4742 perm->host_to_connect, perm->port_to_connect, 4743 ctype, rname); 4744 } 4745 } 4746 error("WARNING: Server requests forwarding for unknown path %.100s", 4747 path); 4748 return NULL; 4749 } 4750 4751 /* Check if connecting to that port is permitted and connect. */ 4752 Channel * 4753 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4754 char *ctype, char *rname, int *reason, const char **errmsg) 4755 { 4756 struct ssh_channels *sc = ssh->chanctxt; 4757 struct permission_set *pset = &sc->local_perms; 4758 struct channel_connect cctx; 4759 Channel *c; 4760 u_int i, permit, permit_adm = 1; 4761 int sock; 4762 struct permission *perm; 4763 4764 permit = pset->all_permitted; 4765 if (!permit) { 4766 for (i = 0; i < pset->num_permitted_user; i++) { 4767 perm = &pset->permitted_user[i]; 4768 if (open_match(perm, host, port)) { 4769 permit = 1; 4770 break; 4771 } 4772 } 4773 } 4774 4775 if (pset->num_permitted_admin > 0) { 4776 permit_adm = 0; 4777 for (i = 0; i < pset->num_permitted_admin; i++) { 4778 perm = &pset->permitted_admin[i]; 4779 if (open_match(perm, host, port)) { 4780 permit_adm = 1; 4781 break; 4782 } 4783 } 4784 } 4785 4786 if (!permit || !permit_adm) { 4787 logit("Received request from %.100s port %d to connect to " 4788 "host %.100s port %d, but the request was denied.", 4789 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4790 if (reason != NULL) 4791 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4792 return NULL; 4793 } 4794 4795 memset(&cctx, 0, sizeof(cctx)); 4796 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4797 &cctx, reason, errmsg); 4798 if (sock == -1) { 4799 channel_connect_ctx_free(&cctx); 4800 return NULL; 4801 } 4802 4803 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4804 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4805 c->host_port = port; 4806 c->path = xstrdup(host); 4807 c->connect_ctx = cctx; 4808 4809 return c; 4810 } 4811 4812 /* Check if connecting to that path is permitted and connect. */ 4813 Channel * 4814 channel_connect_to_path(struct ssh *ssh, const char *path, 4815 char *ctype, char *rname) 4816 { 4817 struct ssh_channels *sc = ssh->chanctxt; 4818 struct permission_set *pset = &sc->local_perms; 4819 u_int i, permit, permit_adm = 1; 4820 struct permission *perm; 4821 4822 permit = pset->all_permitted; 4823 if (!permit) { 4824 for (i = 0; i < pset->num_permitted_user; i++) { 4825 perm = &pset->permitted_user[i]; 4826 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4827 permit = 1; 4828 break; 4829 } 4830 } 4831 } 4832 4833 if (pset->num_permitted_admin > 0) { 4834 permit_adm = 0; 4835 for (i = 0; i < pset->num_permitted_admin; i++) { 4836 perm = &pset->permitted_admin[i]; 4837 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4838 permit_adm = 1; 4839 break; 4840 } 4841 } 4842 } 4843 4844 if (!permit || !permit_adm) { 4845 logit("Received request to connect to path %.100s, " 4846 "but the request was denied.", path); 4847 return NULL; 4848 } 4849 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4850 } 4851 4852 void 4853 channel_send_window_changes(struct ssh *ssh) 4854 { 4855 struct ssh_channels *sc = ssh->chanctxt; 4856 struct winsize ws; 4857 int r; 4858 u_int i; 4859 4860 for (i = 0; i < sc->channels_alloc; i++) { 4861 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4862 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4863 continue; 4864 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4865 continue; 4866 channel_request_start(ssh, i, "window-change", 0); 4867 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4868 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4869 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4870 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4871 (r = sshpkt_send(ssh)) != 0) 4872 fatal_fr(r, "channel %u; send window-change", i); 4873 } 4874 } 4875 4876 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4877 static Channel * 4878 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4879 { 4880 Channel *c; 4881 int r; 4882 4883 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4884 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4885 c->host_port = 0; 4886 c->path = NULL; 4887 4888 /* 4889 * We need to open the channel before we have a FD, 4890 * so that we can get SOCKS header from peer. 4891 */ 4892 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4893 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4894 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4895 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4896 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4897 fatal_fr(r, "channel %i; confirm", c->self); 4898 return c; 4899 } 4900 4901 /* Return CONNECTING socket to remote host:port or local socket path */ 4902 static int 4903 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4904 { 4905 struct ssh_channels *sc = ssh->chanctxt; 4906 struct permission_set *pset = &sc->local_perms; 4907 struct permission *perm; 4908 struct channel_connect cctx; 4909 u_int i, permit_adm = 1; 4910 int sock; 4911 4912 if (pset->num_permitted_admin > 0) { 4913 permit_adm = 0; 4914 for (i = 0; i < pset->num_permitted_admin; i++) { 4915 perm = &pset->permitted_admin[i]; 4916 if (open_match(perm, c->path, c->host_port)) { 4917 permit_adm = 1; 4918 break; 4919 } 4920 } 4921 } 4922 if (!permit_adm) { 4923 debug_f("requested forward not permitted"); 4924 return -1; 4925 } 4926 4927 memset(&cctx, 0, sizeof(cctx)); 4928 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4929 NULL, &cctx, NULL, NULL); 4930 if (sock == -1) 4931 channel_connect_ctx_free(&cctx); 4932 else { 4933 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4934 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4935 c->connect_ctx = cctx; 4936 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4937 } 4938 return sock; 4939 } 4940 4941 /* -- X11 forwarding */ 4942 4943 /* 4944 * Creates an internet domain socket for listening for X11 connections. 4945 * Returns 0 and a suitable display number for the DISPLAY variable 4946 * stored in display_numberp , or -1 if an error occurs. 4947 */ 4948 int 4949 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4950 int x11_use_localhost, int single_connection, 4951 u_int *display_numberp, int **chanids) 4952 { 4953 Channel *nc = NULL; 4954 int display_number, sock; 4955 u_short port; 4956 struct addrinfo hints, *ai, *aitop; 4957 char strport[NI_MAXSERV]; 4958 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4959 4960 if (chanids == NULL) 4961 return -1; 4962 4963 for (display_number = x11_display_offset; 4964 display_number < MAX_DISPLAYS; 4965 display_number++) { 4966 port = 6000 + display_number; 4967 memset(&hints, 0, sizeof(hints)); 4968 hints.ai_family = ssh->chanctxt->IPv4or6; 4969 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4970 hints.ai_socktype = SOCK_STREAM; 4971 snprintf(strport, sizeof strport, "%d", port); 4972 if ((gaierr = getaddrinfo(NULL, strport, 4973 &hints, &aitop)) != 0) { 4974 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4975 return -1; 4976 } 4977 for (ai = aitop; ai; ai = ai->ai_next) { 4978 if (ai->ai_family != AF_INET && 4979 ai->ai_family != AF_INET6) 4980 continue; 4981 sock = socket(ai->ai_family, ai->ai_socktype, 4982 ai->ai_protocol); 4983 if (sock == -1) { 4984 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 4985 #ifdef EPFNOSUPPORT 4986 && (errno != EPFNOSUPPORT) 4987 #endif 4988 ) { 4989 error("socket: %.100s", strerror(errno)); 4990 freeaddrinfo(aitop); 4991 return -1; 4992 } else { 4993 debug("x11_create_display_inet: Socket family %d not supported", 4994 ai->ai_family); 4995 continue; 4996 } 4997 } 4998 if (ai->ai_family == AF_INET6) 4999 sock_set_v6only(sock); 5000 if (x11_use_localhost) 5001 set_reuseaddr(sock); 5002 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5003 debug2_f("bind port %d: %.100s", port, 5004 strerror(errno)); 5005 close(sock); 5006 for (n = 0; n < num_socks; n++) 5007 close(socks[n]); 5008 num_socks = 0; 5009 break; 5010 } 5011 socks[num_socks++] = sock; 5012 if (num_socks == NUM_SOCKS) 5013 break; 5014 } 5015 freeaddrinfo(aitop); 5016 if (num_socks > 0) 5017 break; 5018 } 5019 if (display_number >= MAX_DISPLAYS) { 5020 error("Failed to allocate internet-domain X11 display socket."); 5021 return -1; 5022 } 5023 /* Start listening for connections on the socket. */ 5024 for (n = 0; n < num_socks; n++) { 5025 sock = socks[n]; 5026 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5027 error("listen: %.100s", strerror(errno)); 5028 close(sock); 5029 return -1; 5030 } 5031 } 5032 5033 /* Allocate a channel for each socket. */ 5034 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5035 for (n = 0; n < num_socks; n++) { 5036 sock = socks[n]; 5037 nc = channel_new(ssh, "x11-listener", 5038 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5039 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5040 0, "X11 inet listener", 1); 5041 nc->single_connection = single_connection; 5042 (*chanids)[n] = nc->self; 5043 } 5044 (*chanids)[n] = -1; 5045 5046 /* Return the display number for the DISPLAY environment variable. */ 5047 *display_numberp = display_number; 5048 return 0; 5049 } 5050 5051 static int 5052 connect_local_xsocket_path(const char *pathname) 5053 { 5054 int sock; 5055 struct sockaddr_un addr; 5056 5057 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5058 if (sock == -1) { 5059 error("socket: %.100s", strerror(errno)); 5060 return -1; 5061 } 5062 memset(&addr, 0, sizeof(addr)); 5063 addr.sun_family = AF_UNIX; 5064 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 5065 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5066 return sock; 5067 close(sock); 5068 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5069 return -1; 5070 } 5071 5072 static int 5073 connect_local_xsocket(u_int dnr) 5074 { 5075 char buf[1024]; 5076 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 5077 return connect_local_xsocket_path(buf); 5078 } 5079 5080 #ifdef __APPLE__ 5081 static int 5082 is_path_to_xsocket(const char *display, char *path, size_t pathlen) 5083 { 5084 struct stat sbuf; 5085 5086 if (strlcpy(path, display, pathlen) >= pathlen) { 5087 error("%s: display path too long", __func__); 5088 return 0; 5089 } 5090 if (display[0] != '/') 5091 return 0; 5092 if (stat(path, &sbuf) == 0) { 5093 return 1; 5094 } else { 5095 char *dot = strrchr(path, '.'); 5096 if (dot != NULL) { 5097 *dot = '\0'; 5098 if (stat(path, &sbuf) == 0) { 5099 return 1; 5100 } 5101 } 5102 } 5103 return 0; 5104 } 5105 #endif 5106 5107 int 5108 x11_connect_display(struct ssh *ssh) 5109 { 5110 u_int display_number; 5111 const char *display; 5112 char buf[1024], *cp; 5113 struct addrinfo hints, *ai, *aitop; 5114 char strport[NI_MAXSERV]; 5115 int gaierr, sock = 0; 5116 5117 /* Try to open a socket for the local X server. */ 5118 display = getenv("DISPLAY"); 5119 if (!display) { 5120 error("DISPLAY not set."); 5121 return -1; 5122 } 5123 /* 5124 * Now we decode the value of the DISPLAY variable and make a 5125 * connection to the real X server. 5126 */ 5127 5128 #ifdef __APPLE__ 5129 /* Check if display is a path to a socket (as set by launchd). */ 5130 { 5131 char path[PATH_MAX]; 5132 5133 if (is_path_to_xsocket(display, path, sizeof(path))) { 5134 debug("x11_connect_display: $DISPLAY is launchd"); 5135 5136 /* Create a socket. */ 5137 sock = connect_local_xsocket_path(path); 5138 if (sock < 0) 5139 return -1; 5140 5141 /* OK, we now have a connection to the display. */ 5142 return sock; 5143 } 5144 } 5145 #endif 5146 /* 5147 * Check if it is a unix domain socket. Unix domain displays are in 5148 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5149 */ 5150 if (strncmp(display, "unix:", 5) == 0 || 5151 display[0] == ':') { 5152 /* Connect to the unix domain socket. */ 5153 if (sscanf(strrchr(display, ':') + 1, "%u", 5154 &display_number) != 1) { 5155 error("Could not parse display number from DISPLAY: " 5156 "%.100s", display); 5157 return -1; 5158 } 5159 /* Create a socket. */ 5160 sock = connect_local_xsocket(display_number); 5161 if (sock < 0) 5162 return -1; 5163 5164 /* OK, we now have a connection to the display. */ 5165 return sock; 5166 } 5167 /* 5168 * Connect to an inet socket. The DISPLAY value is supposedly 5169 * hostname:d[.s], where hostname may also be numeric IP address. 5170 */ 5171 strlcpy(buf, display, sizeof(buf)); 5172 cp = strchr(buf, ':'); 5173 if (!cp) { 5174 error("Could not find ':' in DISPLAY: %.100s", display); 5175 return -1; 5176 } 5177 *cp = 0; 5178 /* 5179 * buf now contains the host name. But first we parse the 5180 * display number. 5181 */ 5182 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5183 error("Could not parse display number from DISPLAY: %.100s", 5184 display); 5185 return -1; 5186 } 5187 5188 /* Look up the host address */ 5189 memset(&hints, 0, sizeof(hints)); 5190 hints.ai_family = ssh->chanctxt->IPv4or6; 5191 hints.ai_socktype = SOCK_STREAM; 5192 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5193 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5194 error("%.100s: unknown host. (%s)", buf, 5195 ssh_gai_strerror(gaierr)); 5196 return -1; 5197 } 5198 for (ai = aitop; ai; ai = ai->ai_next) { 5199 /* Create a socket. */ 5200 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5201 if (sock == -1) { 5202 debug2("socket: %.100s", strerror(errno)); 5203 continue; 5204 } 5205 /* Connect it to the display. */ 5206 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5207 debug2("connect %.100s port %u: %.100s", buf, 5208 6000 + display_number, strerror(errno)); 5209 close(sock); 5210 continue; 5211 } 5212 /* Success */ 5213 break; 5214 } 5215 freeaddrinfo(aitop); 5216 if (!ai) { 5217 error("connect %.100s port %u: %.100s", buf, 5218 6000 + display_number, strerror(errno)); 5219 return -1; 5220 } 5221 set_nodelay(sock); 5222 return sock; 5223 } 5224 5225 /* 5226 * Requests forwarding of X11 connections, generates fake authentication 5227 * data, and enables authentication spoofing. 5228 * This should be called in the client only. 5229 */ 5230 void 5231 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5232 const char *disp, const char *proto, const char *data, int want_reply) 5233 { 5234 struct ssh_channels *sc = ssh->chanctxt; 5235 u_int data_len = (u_int) strlen(data) / 2; 5236 u_int i, value; 5237 const char *cp; 5238 char *new_data; 5239 int r, screen_number; 5240 5241 if (sc->x11_saved_display == NULL) 5242 sc->x11_saved_display = xstrdup(disp); 5243 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5244 error("x11_request_forwarding_with_spoofing: different " 5245 "$DISPLAY already forwarded"); 5246 return; 5247 } 5248 5249 cp = strchr(disp, ':'); 5250 if (cp) 5251 cp = strchr(cp, '.'); 5252 if (cp) 5253 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5254 else 5255 screen_number = 0; 5256 5257 if (sc->x11_saved_proto == NULL) { 5258 /* Save protocol name. */ 5259 sc->x11_saved_proto = xstrdup(proto); 5260 5261 /* Extract real authentication data. */ 5262 sc->x11_saved_data = xmalloc(data_len); 5263 for (i = 0; i < data_len; i++) { 5264 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5265 fatal("x11_request_forwarding: bad " 5266 "authentication data: %.100s", data); 5267 } 5268 sc->x11_saved_data[i] = value; 5269 } 5270 sc->x11_saved_data_len = data_len; 5271 5272 /* Generate fake data of the same length. */ 5273 sc->x11_fake_data = xmalloc(data_len); 5274 arc4random_buf(sc->x11_fake_data, data_len); 5275 sc->x11_fake_data_len = data_len; 5276 } 5277 5278 /* Convert the fake data into hex. */ 5279 new_data = tohex(sc->x11_fake_data, data_len); 5280 5281 /* Send the request packet. */ 5282 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5283 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5284 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5285 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5286 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5287 (r = sshpkt_send(ssh)) != 0 || 5288 (r = ssh_packet_write_wait(ssh)) != 0) 5289 fatal_fr(r, "send x11-req"); 5290 free(new_data); 5291 } 5292