1 /* $OpenBSD: channels.c,v 1.430 2023/03/10 03:01:51 dtucker Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include "includes.h" 43 44 #include <sys/types.h> 45 #include <sys/stat.h> 46 #include <sys/ioctl.h> 47 #include <sys/un.h> 48 #include <sys/socket.h> 49 #ifdef HAVE_SYS_TIME_H 50 # include <sys/time.h> 51 #endif 52 53 #include <netinet/in.h> 54 #include <arpa/inet.h> 55 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <limits.h> 59 #include <netdb.h> 60 #ifdef HAVE_POLL_H 61 #include <poll.h> 62 #endif 63 #include <stdarg.h> 64 #ifdef HAVE_STDINT_H 65 # include <stdint.h> 66 #endif 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <string.h> 70 #include <termios.h> 71 #include <unistd.h> 72 73 #include "openbsd-compat/sys-queue.h" 74 #include "xmalloc.h" 75 #include "ssh.h" 76 #include "ssh2.h" 77 #include "ssherr.h" 78 #include "sshbuf.h" 79 #include "packet.h" 80 #include "log.h" 81 #include "misc.h" 82 #include "channels.h" 83 #include "compat.h" 84 #include "canohost.h" 85 #include "sshkey.h" 86 #include "authfd.h" 87 #include "pathnames.h" 88 #include "match.h" 89 90 /* XXX remove once we're satisfied there's no lurking bugs */ 91 /* #define DEBUG_CHANNEL_POLL 1 */ 92 93 /* -- agent forwarding */ 94 #define NUM_SOCKS 10 95 96 /* -- tcp forwarding */ 97 /* special-case port number meaning allow any port */ 98 #define FWD_PERMIT_ANY_PORT 0 99 100 /* special-case wildcard meaning allow any host */ 101 #define FWD_PERMIT_ANY_HOST "*" 102 103 /* -- X11 forwarding */ 104 /* Maximum number of fake X11 displays to try. */ 105 #define MAX_DISPLAYS 1000 106 107 /* Per-channel callback for pre/post IO actions */ 108 typedef void chan_fn(struct ssh *, Channel *c); 109 110 /* 111 * Data structure for storing which hosts are permitted for forward requests. 112 * The local sides of any remote forwards are stored in this array to prevent 113 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 114 * network (which might be behind a firewall). 115 */ 116 /* XXX: streamlocal wants a path instead of host:port */ 117 /* Overload host_to_connect; we could just make this match Forward */ 118 /* XXX - can we use listen_host instead of listen_path? */ 119 struct permission { 120 char *host_to_connect; /* Connect to 'host'. */ 121 int port_to_connect; /* Connect to 'port'. */ 122 char *listen_host; /* Remote side should listen address. */ 123 char *listen_path; /* Remote side should listen path. */ 124 int listen_port; /* Remote side should listen port. */ 125 Channel *downstream; /* Downstream mux*/ 126 }; 127 128 /* 129 * Stores the forwarding permission state for a single direction (local or 130 * remote). 131 */ 132 struct permission_set { 133 /* 134 * List of all local permitted host/port pairs to allow for the 135 * user. 136 */ 137 u_int num_permitted_user; 138 struct permission *permitted_user; 139 140 /* 141 * List of all permitted host/port pairs to allow for the admin. 142 */ 143 u_int num_permitted_admin; 144 struct permission *permitted_admin; 145 146 /* 147 * If this is true, all opens/listens are permitted. This is the 148 * case on the server on which we have to trust the client anyway, 149 * and the user could do anything after logging in. 150 */ 151 int all_permitted; 152 }; 153 154 /* Used to record timeouts per channel type */ 155 struct ssh_channel_timeout { 156 char *type_pattern; 157 u_int timeout_secs; 158 }; 159 160 /* Master structure for channels state */ 161 struct ssh_channels { 162 /* 163 * Pointer to an array containing all allocated channels. The array 164 * is dynamically extended as needed. 165 */ 166 Channel **channels; 167 168 /* 169 * Size of the channel array. All slots of the array must always be 170 * initialized (at least the type field); unused slots set to NULL 171 */ 172 u_int channels_alloc; 173 174 /* 175 * 'channel_pre*' are called just before IO to add any bits 176 * relevant to channels in the c->io_want bitmasks. 177 * 178 * 'channel_post*': perform any appropriate operations for 179 * channels which have c->io_ready events pending. 180 */ 181 chan_fn **channel_pre; 182 chan_fn **channel_post; 183 184 /* -- tcp forwarding */ 185 struct permission_set local_perms; 186 struct permission_set remote_perms; 187 188 /* -- X11 forwarding */ 189 190 /* Saved X11 local (client) display. */ 191 char *x11_saved_display; 192 193 /* Saved X11 authentication protocol name. */ 194 char *x11_saved_proto; 195 196 /* Saved X11 authentication data. This is the real data. */ 197 char *x11_saved_data; 198 u_int x11_saved_data_len; 199 200 /* Deadline after which all X11 connections are refused */ 201 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 u_int timeout_secs) 316 { 317 struct ssh_channels *sc = ssh->chanctxt; 318 319 debug2_f("channel type \"%s\" timeout %u seconds", 320 type_pattern, timeout_secs); 321 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 322 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 323 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 324 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 325 sc->ntimeouts++; 326 } 327 328 /* Clears all previously-added channel timeouts */ 329 void 330 channel_clear_timeouts(struct ssh *ssh) 331 { 332 struct ssh_channels *sc = ssh->chanctxt; 333 size_t i; 334 335 debug3_f("clearing"); 336 for (i = 0; i < sc->ntimeouts; i++) 337 free(sc->timeouts[i].type_pattern); 338 free(sc->timeouts); 339 sc->timeouts = NULL; 340 sc->ntimeouts = 0; 341 } 342 343 static u_int 344 lookup_timeout(struct ssh *ssh, const char *type) 345 { 346 struct ssh_channels *sc = ssh->chanctxt; 347 size_t i; 348 349 for (i = 0; i < sc->ntimeouts; i++) { 350 if (match_pattern(type, sc->timeouts[i].type_pattern)) 351 return sc->timeouts[i].timeout_secs; 352 } 353 354 return 0; 355 } 356 357 /* 358 * Sets "extended type" of a channel; used by session layer to add additional 359 * information about channel types (e.g. shell, login, subsystem) that can then 360 * be used to select timeouts. 361 * Will reset c->inactive_deadline as a side-effect. 362 */ 363 void 364 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 365 { 366 Channel *c; 367 368 if ((c = channel_by_id(ssh, id)) == NULL) 369 fatal_f("missing channel %d", id); 370 if (c->xctype != NULL) 371 free(c->xctype); 372 c->xctype = xstrdup(xctype); 373 /* Type has changed, so look up inactivity deadline again */ 374 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 375 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 376 c->inactive_deadline); 377 } 378 379 /* 380 * Register filedescriptors for a channel, used when allocating a channel or 381 * when the channel consumer/producer is ready, e.g. shell exec'd 382 */ 383 static void 384 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 385 int extusage, int nonblock, int is_tty) 386 { 387 int val; 388 389 if (rfd != -1) 390 (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, u_short port_to_connect, 1638 int in, int out, int nonblock) 1639 { 1640 Channel *c; 1641 1642 debug_f("%s:%d", host_to_connect, port_to_connect); 1643 1644 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1645 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1646 0, "stdio-forward", nonblock); 1647 1648 c->path = xstrdup(host_to_connect); 1649 c->host_port = port_to_connect; 1650 c->listening_port = 0; 1651 c->force_drain = 1; 1652 1653 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1654 port_open_helper(ssh, c, "direct-tcpip"); 1655 1656 return c; 1657 } 1658 1659 /* dynamic port forwarding */ 1660 static void 1661 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1662 { 1663 const u_char *p; 1664 u_int have; 1665 int ret; 1666 1667 c->io_want = 0; 1668 have = sshbuf_len(c->input); 1669 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1670 /* sshbuf_dump(c->input, stderr); */ 1671 /* check if the fixed size part of the packet is in buffer. */ 1672 if (have < 3) { 1673 /* need more */ 1674 c->io_want |= SSH_CHAN_IO_RFD; 1675 return; 1676 } 1677 /* try to guess the protocol */ 1678 p = sshbuf_ptr(c->input); 1679 /* XXX sshbuf_peek_u8? */ 1680 switch (p[0]) { 1681 case 0x04: 1682 ret = channel_decode_socks4(c, c->input, c->output); 1683 break; 1684 case 0x05: 1685 ret = channel_decode_socks5(c, c->input, c->output); 1686 break; 1687 default: 1688 ret = -1; 1689 break; 1690 } 1691 if (ret < 0) { 1692 chan_mark_dead(ssh, c); 1693 } else if (ret == 0) { 1694 debug2("channel %d: pre_dynamic: need more", c->self); 1695 /* need more */ 1696 c->io_want |= SSH_CHAN_IO_RFD; 1697 if (sshbuf_len(c->output)) 1698 c->io_want |= SSH_CHAN_IO_WFD; 1699 } else { 1700 /* switch to the next state */ 1701 c->type = SSH_CHANNEL_OPENING; 1702 port_open_helper(ssh, c, "direct-tcpip"); 1703 } 1704 } 1705 1706 /* simulate read-error */ 1707 static void 1708 rdynamic_close(struct ssh *ssh, Channel *c) 1709 { 1710 c->type = SSH_CHANNEL_OPEN; 1711 channel_force_close(ssh, c, 0); 1712 } 1713 1714 /* reverse dynamic port forwarding */ 1715 static void 1716 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1717 { 1718 const u_char *p; 1719 u_int have, len; 1720 int r, ret; 1721 1722 have = sshbuf_len(c->output); 1723 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1724 /* sshbuf_dump(c->output, stderr); */ 1725 /* EOF received */ 1726 if (c->flags & CHAN_EOF_RCVD) { 1727 if ((r = sshbuf_consume(c->output, have)) != 0) 1728 fatal_fr(r, "channel %d: consume", c->self); 1729 rdynamic_close(ssh, c); 1730 return; 1731 } 1732 /* check if the fixed size part of the packet is in buffer. */ 1733 if (have < 3) 1734 return; 1735 /* try to guess the protocol */ 1736 p = sshbuf_ptr(c->output); 1737 switch (p[0]) { 1738 case 0x04: 1739 /* switch input/output for reverse forwarding */ 1740 ret = channel_decode_socks4(c, c->output, c->input); 1741 break; 1742 case 0x05: 1743 ret = channel_decode_socks5(c, c->output, c->input); 1744 break; 1745 default: 1746 ret = -1; 1747 break; 1748 } 1749 if (ret < 0) { 1750 rdynamic_close(ssh, c); 1751 } else if (ret == 0) { 1752 debug2("channel %d: pre_rdynamic: need more", c->self); 1753 /* send socks request to peer */ 1754 len = sshbuf_len(c->input); 1755 if (len > 0 && len < c->remote_window) { 1756 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1757 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1758 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1759 (r = sshpkt_send(ssh)) != 0) { 1760 fatal_fr(r, "channel %i: rdynamic", c->self); 1761 } 1762 if ((r = sshbuf_consume(c->input, len)) != 0) 1763 fatal_fr(r, "channel %d: consume", c->self); 1764 c->remote_window -= len; 1765 } 1766 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1767 /* the connect failed */ 1768 rdynamic_close(ssh, c); 1769 } 1770 } 1771 1772 /* This is our fake X11 server socket. */ 1773 static void 1774 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1775 { 1776 Channel *nc; 1777 struct sockaddr_storage addr; 1778 int r, newsock, oerrno, remote_port; 1779 socklen_t addrlen; 1780 char buf[16384], *remote_ipaddr; 1781 1782 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1783 return; 1784 1785 debug("X11 connection requested."); 1786 addrlen = sizeof(addr); 1787 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1788 if (c->single_connection) { 1789 oerrno = errno; 1790 debug2("single_connection: closing X11 listener."); 1791 channel_close_fd(ssh, c, &c->sock); 1792 chan_mark_dead(ssh, c); 1793 errno = oerrno; 1794 } 1795 if (newsock == -1) { 1796 if (errno != EINTR && errno != EWOULDBLOCK && 1797 errno != ECONNABORTED) 1798 error("accept: %.100s", strerror(errno)); 1799 if (errno == EMFILE || errno == ENFILE) 1800 c->notbefore = monotime() + 1; 1801 return; 1802 } 1803 set_nodelay(newsock); 1804 remote_ipaddr = get_peer_ipaddr(newsock); 1805 remote_port = get_peer_port(newsock); 1806 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1807 remote_ipaddr, remote_port); 1808 1809 nc = channel_new(ssh, "x11-connection", 1810 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1811 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1812 open_preamble(ssh, __func__, nc, "x11"); 1813 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1814 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1815 fatal_fr(r, "channel %i: reply", c->self); 1816 } 1817 if ((r = sshpkt_send(ssh)) != 0) 1818 fatal_fr(r, "channel %i: send", c->self); 1819 free(remote_ipaddr); 1820 } 1821 1822 static void 1823 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1824 { 1825 char *local_ipaddr = get_local_ipaddr(c->sock); 1826 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1827 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1828 int remote_port = get_peer_port(c->sock); 1829 int r; 1830 1831 if (remote_port == -1) { 1832 /* Fake addr/port to appease peers that validate it (Tectia) */ 1833 free(remote_ipaddr); 1834 remote_ipaddr = xstrdup("127.0.0.1"); 1835 remote_port = 65535; 1836 } 1837 1838 free(c->remote_name); 1839 xasprintf(&c->remote_name, 1840 "%s: listening port %d for %.100s port %d, " 1841 "connect from %.200s port %d to %.100s port %d", 1842 rtype, c->listening_port, c->path, c->host_port, 1843 remote_ipaddr, remote_port, local_ipaddr, local_port); 1844 1845 open_preamble(ssh, __func__, c, rtype); 1846 if (strcmp(rtype, "direct-tcpip") == 0) { 1847 /* target host, port */ 1848 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1849 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1850 fatal_fr(r, "channel %i: reply", c->self); 1851 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1852 /* target path */ 1853 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1854 fatal_fr(r, "channel %i: reply", c->self); 1855 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1856 /* listen path */ 1857 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1858 fatal_fr(r, "channel %i: reply", c->self); 1859 } else { 1860 /* listen address, port */ 1861 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1862 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1863 fatal_fr(r, "channel %i: reply", c->self); 1864 } 1865 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1866 /* reserved for future owner/mode info */ 1867 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1868 fatal_fr(r, "channel %i: reply", c->self); 1869 } else { 1870 /* originator host and port */ 1871 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1872 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1873 fatal_fr(r, "channel %i: reply", c->self); 1874 } 1875 if ((r = sshpkt_send(ssh)) != 0) 1876 fatal_fr(r, "channel %i: send", c->self); 1877 free(remote_ipaddr); 1878 free(local_ipaddr); 1879 } 1880 1881 void 1882 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1883 { 1884 ssh->chanctxt->x11_refuse_time = refuse_time; 1885 } 1886 1887 /* 1888 * This socket is listening for connections to a forwarded TCP/IP port. 1889 */ 1890 static void 1891 channel_post_port_listener(struct ssh *ssh, Channel *c) 1892 { 1893 Channel *nc; 1894 struct sockaddr_storage addr; 1895 int newsock, nextstate; 1896 socklen_t addrlen; 1897 char *rtype; 1898 1899 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1900 return; 1901 1902 debug("Connection to port %d forwarding to %.100s port %d requested.", 1903 c->listening_port, c->path, c->host_port); 1904 1905 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1906 nextstate = SSH_CHANNEL_OPENING; 1907 rtype = "forwarded-tcpip"; 1908 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1909 nextstate = SSH_CHANNEL_OPENING; 1910 rtype = "forwarded-streamlocal@openssh.com"; 1911 } else if (c->host_port == PORT_STREAMLOCAL) { 1912 nextstate = SSH_CHANNEL_OPENING; 1913 rtype = "direct-streamlocal@openssh.com"; 1914 } else if (c->host_port == 0) { 1915 nextstate = SSH_CHANNEL_DYNAMIC; 1916 rtype = "dynamic-tcpip"; 1917 } else { 1918 nextstate = SSH_CHANNEL_OPENING; 1919 rtype = "direct-tcpip"; 1920 } 1921 1922 addrlen = sizeof(addr); 1923 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1924 if (newsock == -1) { 1925 if (errno != EINTR && errno != EWOULDBLOCK && 1926 errno != ECONNABORTED) 1927 error("accept: %.100s", strerror(errno)); 1928 if (errno == EMFILE || errno == ENFILE) 1929 c->notbefore = monotime() + 1; 1930 return; 1931 } 1932 if (c->host_port != PORT_STREAMLOCAL) 1933 set_nodelay(newsock); 1934 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1935 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1936 nc->listening_port = c->listening_port; 1937 nc->host_port = c->host_port; 1938 if (c->path != NULL) 1939 nc->path = xstrdup(c->path); 1940 1941 if (nextstate != SSH_CHANNEL_DYNAMIC) 1942 port_open_helper(ssh, nc, rtype); 1943 } 1944 1945 /* 1946 * This is the authentication agent socket listening for connections from 1947 * clients. 1948 */ 1949 static void 1950 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1951 { 1952 Channel *nc; 1953 int r, newsock; 1954 struct sockaddr_storage addr; 1955 socklen_t addrlen; 1956 1957 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1958 return; 1959 1960 addrlen = sizeof(addr); 1961 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1962 if (newsock == -1) { 1963 error("accept from auth socket: %.100s", strerror(errno)); 1964 if (errno == EMFILE || errno == ENFILE) 1965 c->notbefore = monotime() + 1; 1966 return; 1967 } 1968 nc = channel_new(ssh, "agent-connection", 1969 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1970 c->local_window_max, c->local_maxpacket, 1971 0, "accepted auth socket", 1); 1972 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1973 if ((r = sshpkt_send(ssh)) != 0) 1974 fatal_fr(r, "channel %i", c->self); 1975 } 1976 1977 static void 1978 channel_post_connecting(struct ssh *ssh, Channel *c) 1979 { 1980 int err = 0, sock, isopen, r; 1981 socklen_t sz = sizeof(err); 1982 1983 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 1984 return; 1985 if (!c->have_remote_id) 1986 fatal_f("channel %d: no remote id", c->self); 1987 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1988 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1989 1990 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 1991 err = errno; 1992 error("getsockopt SO_ERROR failed"); 1993 } 1994 1995 if (err == 0) { 1996 /* Non-blocking connection completed */ 1997 debug("channel %d: connected to %s port %d", 1998 c->self, c->connect_ctx.host, c->connect_ctx.port); 1999 channel_connect_ctx_free(&c->connect_ctx); 2000 c->type = SSH_CHANNEL_OPEN; 2001 c->lastused = monotime(); 2002 if (isopen) { 2003 /* no message necessary */ 2004 } else { 2005 if ((r = sshpkt_start(ssh, 2006 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2007 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2008 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2009 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2010 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2011 (r = sshpkt_send(ssh)) != 0) 2012 fatal_fr(r, "channel %i open confirm", c->self); 2013 } 2014 return; 2015 } 2016 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2017 return; 2018 2019 /* Non-blocking connection failed */ 2020 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2021 2022 /* Try next address, if any */ 2023 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2024 /* Exhausted all addresses for this destination */ 2025 error("connect_to %.100s port %d: failed.", 2026 c->connect_ctx.host, c->connect_ctx.port); 2027 channel_connect_ctx_free(&c->connect_ctx); 2028 if (isopen) { 2029 rdynamic_close(ssh, c); 2030 } else { 2031 if ((r = sshpkt_start(ssh, 2032 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2033 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2034 (r = sshpkt_put_u32(ssh, 2035 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2036 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2037 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2038 (r = sshpkt_send(ssh)) != 0) 2039 fatal_fr(r, "channel %i: failure", c->self); 2040 chan_mark_dead(ssh, c); 2041 } 2042 } 2043 2044 /* New non-blocking connection in progress */ 2045 close(c->sock); 2046 c->sock = c->rfd = c->wfd = sock; 2047 } 2048 2049 static int 2050 channel_handle_rfd(struct ssh *ssh, Channel *c) 2051 { 2052 char buf[CHAN_RBUF]; 2053 ssize_t len; 2054 int r, force; 2055 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2056 int pty_zeroread = 0; 2057 2058 #ifdef PTY_ZEROREAD 2059 /* Bug on AIX: read(1) can return 0 for a non-closed fd */ 2060 pty_zeroread = c->isatty; 2061 #endif 2062 2063 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2064 2065 if (!force && (c->io_ready & SSH_CHAN_IO_RFD) == 0) 2066 return 1; 2067 if ((avail = sshbuf_avail(c->input)) == 0) 2068 return 1; /* Shouldn't happen */ 2069 2070 /* 2071 * For "simple" channels (i.e. not datagram or filtered), we can 2072 * read directly to the channel buffer. 2073 */ 2074 if (!pty_zeroread && c->input_filter == NULL && !c->datagram) { 2075 /* Only OPEN channels have valid rwin */ 2076 if (c->type == SSH_CHANNEL_OPEN) { 2077 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2078 return 1; /* shouldn't happen */ 2079 if (maxlen > c->remote_window - have) 2080 maxlen = c->remote_window - have; 2081 } 2082 if (maxlen > avail) 2083 maxlen = avail; 2084 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2085 if (errno == EINTR || (!force && 2086 (errno == EAGAIN || errno == EWOULDBLOCK))) 2087 return 1; 2088 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2089 c->self, c->rfd, maxlen, ssh_err(r)); 2090 goto rfail; 2091 } 2092 if (nr != 0) 2093 c->lastused = monotime(); 2094 return 1; 2095 } 2096 2097 errno = 0; 2098 len = read(c->rfd, buf, sizeof(buf)); 2099 /* fixup AIX zero-length read with errno set to look more like errors */ 2100 if (pty_zeroread && len == 0 && errno != 0) 2101 len = -1; 2102 if (len == -1 && (errno == EINTR || 2103 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 2104 return 1; 2105 if (len < 0 || (!pty_zeroread && len == 0)) { 2106 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2107 c->self, c->rfd, len, 2108 len == 0 ? "closed" : strerror(errno)); 2109 rfail: 2110 if (c->type != SSH_CHANNEL_OPEN) { 2111 debug2("channel %d: not open", c->self); 2112 chan_mark_dead(ssh, c); 2113 return -1; 2114 } else { 2115 chan_read_failed(ssh, c); 2116 } 2117 return -1; 2118 } 2119 c->lastused = monotime(); 2120 if (c->input_filter != NULL) { 2121 if (c->input_filter(ssh, c, buf, len) == -1) { 2122 debug2("channel %d: filter stops", c->self); 2123 chan_read_failed(ssh, c); 2124 } 2125 } else if (c->datagram) { 2126 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2127 fatal_fr(r, "channel %i: put datagram", c->self); 2128 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2129 fatal_fr(r, "channel %i: put data", c->self); 2130 2131 return 1; 2132 } 2133 2134 static int 2135 channel_handle_wfd(struct ssh *ssh, Channel *c) 2136 { 2137 struct termios tio; 2138 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2139 size_t dlen, olen = 0; 2140 int r, len; 2141 2142 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2143 return 1; 2144 if (sshbuf_len(c->output) == 0) 2145 return 1; 2146 2147 /* Send buffered output data to the socket. */ 2148 olen = sshbuf_len(c->output); 2149 if (c->output_filter != NULL) { 2150 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2151 debug2("channel %d: filter stops", c->self); 2152 if (c->type != SSH_CHANNEL_OPEN) 2153 chan_mark_dead(ssh, c); 2154 else 2155 chan_write_failed(ssh, c); 2156 return -1; 2157 } 2158 } else if (c->datagram) { 2159 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2160 fatal_fr(r, "channel %i: get datagram", c->self); 2161 buf = data; 2162 } else { 2163 buf = data = sshbuf_mutable_ptr(c->output); 2164 dlen = sshbuf_len(c->output); 2165 } 2166 2167 if (c->datagram) { 2168 /* ignore truncated writes, datagrams might get lost */ 2169 len = write(c->wfd, buf, dlen); 2170 free(data); 2171 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2172 errno == EWOULDBLOCK)) 2173 return 1; 2174 if (len <= 0) 2175 goto write_fail; 2176 goto out; 2177 } 2178 2179 #ifdef _AIX 2180 /* XXX: Later AIX versions can't push as much data to tty */ 2181 if (c->wfd_isatty) 2182 dlen = MINIMUM(dlen, 8*1024); 2183 #endif 2184 2185 len = write(c->wfd, buf, dlen); 2186 if (len == -1 && 2187 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 2188 return 1; 2189 if (len <= 0) { 2190 write_fail: 2191 if (c->type != SSH_CHANNEL_OPEN) { 2192 debug2("channel %d: not open", c->self); 2193 chan_mark_dead(ssh, c); 2194 return -1; 2195 } else { 2196 chan_write_failed(ssh, c); 2197 } 2198 return -1; 2199 } 2200 c->lastused = monotime(); 2201 #ifndef BROKEN_TCGETATTR_ICANON 2202 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2203 if (tcgetattr(c->wfd, &tio) == 0 && 2204 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2205 /* 2206 * Simulate echo to reduce the impact of 2207 * traffic analysis. We need to match the 2208 * size of a SSH2_MSG_CHANNEL_DATA message 2209 * (4 byte channel id + buf) 2210 */ 2211 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2212 (r = sshpkt_send(ssh)) != 0) 2213 fatal_fr(r, "channel %i: ignore", c->self); 2214 } 2215 } 2216 #endif /* BROKEN_TCGETATTR_ICANON */ 2217 if ((r = sshbuf_consume(c->output, len)) != 0) 2218 fatal_fr(r, "channel %i: consume", c->self); 2219 out: 2220 c->local_consumed += olen - sshbuf_len(c->output); 2221 2222 return 1; 2223 } 2224 2225 static int 2226 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2227 { 2228 int r; 2229 ssize_t len; 2230 2231 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2232 return 1; 2233 if (sshbuf_len(c->extended) == 0) 2234 return 1; 2235 2236 len = write(c->efd, sshbuf_ptr(c->extended), 2237 sshbuf_len(c->extended)); 2238 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2239 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2240 errno == EWOULDBLOCK)) 2241 return 1; 2242 if (len <= 0) { 2243 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2244 channel_close_fd(ssh, c, &c->efd); 2245 } else { 2246 if ((r = sshbuf_consume(c->extended, len)) != 0) 2247 fatal_fr(r, "channel %i: consume", c->self); 2248 c->local_consumed += len; 2249 c->lastused = monotime(); 2250 } 2251 return 1; 2252 } 2253 2254 static int 2255 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2256 { 2257 char buf[CHAN_RBUF]; 2258 ssize_t len; 2259 int r, force; 2260 2261 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2262 2263 if (!force && (c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2264 return 1; 2265 2266 len = read(c->efd, buf, sizeof(buf)); 2267 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2268 if (len == -1 && (errno == EINTR || ((errno == EAGAIN || 2269 errno == EWOULDBLOCK) && !force))) 2270 return 1; 2271 if (len <= 0) { 2272 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2273 channel_close_fd(ssh, c, &c->efd); 2274 return 1; 2275 } 2276 c->lastused = monotime(); 2277 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2278 debug3("channel %d: discard efd", c->self); 2279 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2280 fatal_fr(r, "channel %i: append", c->self); 2281 return 1; 2282 } 2283 2284 static int 2285 channel_handle_efd(struct ssh *ssh, Channel *c) 2286 { 2287 if (c->efd == -1) 2288 return 1; 2289 2290 /** XXX handle drain efd, too */ 2291 2292 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2293 return channel_handle_efd_write(ssh, c); 2294 else if (c->extended_usage == CHAN_EXTENDED_READ || 2295 c->extended_usage == CHAN_EXTENDED_IGNORE) 2296 return channel_handle_efd_read(ssh, c); 2297 2298 return 1; 2299 } 2300 2301 static int 2302 channel_check_window(struct ssh *ssh, Channel *c) 2303 { 2304 int r; 2305 2306 if (c->type == SSH_CHANNEL_OPEN && 2307 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2308 ((c->local_window_max - c->local_window > 2309 c->local_maxpacket*3) || 2310 c->local_window < c->local_window_max/2) && 2311 c->local_consumed > 0) { 2312 if (!c->have_remote_id) 2313 fatal_f("channel %d: no remote id", c->self); 2314 if ((r = sshpkt_start(ssh, 2315 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2316 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2317 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2318 (r = sshpkt_send(ssh)) != 0) { 2319 fatal_fr(r, "channel %i", c->self); 2320 } 2321 debug2("channel %d: window %d sent adjust %d", c->self, 2322 c->local_window, c->local_consumed); 2323 c->local_window += c->local_consumed; 2324 c->local_consumed = 0; 2325 } 2326 return 1; 2327 } 2328 2329 static void 2330 channel_post_open(struct ssh *ssh, Channel *c) 2331 { 2332 channel_handle_rfd(ssh, c); 2333 channel_handle_wfd(ssh, c); 2334 channel_handle_efd(ssh, c); 2335 channel_check_window(ssh, c); 2336 } 2337 2338 static u_int 2339 read_mux(struct ssh *ssh, Channel *c, u_int need) 2340 { 2341 char buf[CHAN_RBUF]; 2342 ssize_t len; 2343 u_int rlen; 2344 int r; 2345 2346 if (sshbuf_len(c->input) < need) { 2347 rlen = need - sshbuf_len(c->input); 2348 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2349 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2350 return sshbuf_len(c->input); 2351 if (len <= 0) { 2352 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2353 c->self, c->rfd, len); 2354 chan_read_failed(ssh, c); 2355 return 0; 2356 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2357 fatal_fr(r, "channel %i: append", c->self); 2358 } 2359 return sshbuf_len(c->input); 2360 } 2361 2362 static void 2363 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2364 { 2365 u_int need; 2366 2367 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2368 return; 2369 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2370 return; 2371 if (c->mux_pause) 2372 return; 2373 2374 /* 2375 * Don't not read past the precise end of packets to 2376 * avoid disrupting fd passing. 2377 */ 2378 if (read_mux(ssh, c, 4) < 4) /* read header */ 2379 return; 2380 /* XXX sshbuf_peek_u32 */ 2381 need = PEEK_U32(sshbuf_ptr(c->input)); 2382 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2383 if (need > CHANNEL_MUX_MAX_PACKET) { 2384 debug2("channel %d: packet too big %u > %u", 2385 c->self, CHANNEL_MUX_MAX_PACKET, need); 2386 chan_rcvd_oclose(ssh, c); 2387 return; 2388 } 2389 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2390 return; 2391 if (c->mux_rcb(ssh, c) != 0) { 2392 debug("channel %d: mux_rcb failed", c->self); 2393 chan_mark_dead(ssh, c); 2394 return; 2395 } 2396 } 2397 2398 static void 2399 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2400 { 2401 ssize_t len; 2402 int r; 2403 2404 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2405 return; 2406 if (sshbuf_len(c->output) == 0) 2407 return; 2408 2409 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2410 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2411 return; 2412 if (len <= 0) { 2413 chan_mark_dead(ssh, c); 2414 return; 2415 } 2416 if ((r = sshbuf_consume(c->output, len)) != 0) 2417 fatal_fr(r, "channel %i: consume", c->self); 2418 } 2419 2420 static void 2421 channel_post_mux_client(struct ssh *ssh, Channel *c) 2422 { 2423 channel_post_mux_client_read(ssh, c); 2424 channel_post_mux_client_write(ssh, c); 2425 } 2426 2427 static void 2428 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2429 { 2430 Channel *nc; 2431 struct sockaddr_storage addr; 2432 socklen_t addrlen; 2433 int newsock; 2434 uid_t euid; 2435 gid_t egid; 2436 2437 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2438 return; 2439 2440 debug("multiplexing control connection"); 2441 2442 /* 2443 * Accept connection on control socket 2444 */ 2445 memset(&addr, 0, sizeof(addr)); 2446 addrlen = sizeof(addr); 2447 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2448 &addrlen)) == -1) { 2449 error_f("accept: %s", strerror(errno)); 2450 if (errno == EMFILE || errno == ENFILE) 2451 c->notbefore = monotime() + 1; 2452 return; 2453 } 2454 2455 if (getpeereid(newsock, &euid, &egid) == -1) { 2456 error_f("getpeereid failed: %s", strerror(errno)); 2457 close(newsock); 2458 return; 2459 } 2460 if ((euid != 0) && (getuid() != euid)) { 2461 error("multiplex uid mismatch: peer euid %u != uid %u", 2462 (u_int)euid, (u_int)getuid()); 2463 close(newsock); 2464 return; 2465 } 2466 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2467 newsock, newsock, -1, c->local_window_max, 2468 c->local_maxpacket, 0, "mux-control", 1); 2469 nc->mux_rcb = c->mux_rcb; 2470 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2471 /* establish state */ 2472 nc->mux_rcb(ssh, nc); 2473 /* mux state transitions must not elicit protocol messages */ 2474 nc->flags |= CHAN_LOCAL; 2475 } 2476 2477 static void 2478 channel_handler_init(struct ssh_channels *sc) 2479 { 2480 chan_fn **pre, **post; 2481 2482 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2483 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2484 fatal_f("allocation failed"); 2485 2486 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2487 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2488 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2489 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2490 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2491 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2492 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2493 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2494 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2495 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2496 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2497 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2498 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2499 2500 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2501 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2502 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2503 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2504 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2505 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2506 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2507 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2508 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2509 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2510 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2511 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2512 2513 sc->channel_pre = pre; 2514 sc->channel_post = post; 2515 } 2516 2517 /* gc dead channels */ 2518 static void 2519 channel_garbage_collect(struct ssh *ssh, Channel *c) 2520 { 2521 if (c == NULL) 2522 return; 2523 if (c->detach_user != NULL) { 2524 if (!chan_is_dead(ssh, c, c->detach_close)) 2525 return; 2526 2527 debug2("channel %d: gc: notify user", c->self); 2528 c->detach_user(ssh, c->self, 0, NULL); 2529 /* if we still have a callback */ 2530 if (c->detach_user != NULL) 2531 return; 2532 debug2("channel %d: gc: user detached", c->self); 2533 } 2534 if (!chan_is_dead(ssh, c, 1)) 2535 return; 2536 debug2("channel %d: garbage collecting", c->self); 2537 channel_free(ssh, c); 2538 } 2539 2540 enum channel_table { CHAN_PRE, CHAN_POST }; 2541 2542 static void 2543 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2544 { 2545 struct ssh_channels *sc = ssh->chanctxt; 2546 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2547 u_int i, oalloc; 2548 Channel *c; 2549 time_t now; 2550 2551 now = monotime(); 2552 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2553 c = sc->channels[i]; 2554 if (c == NULL) 2555 continue; 2556 /* Try to keep IO going while rekeying */ 2557 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2558 continue; 2559 if (c->delayed) { 2560 if (table == CHAN_PRE) 2561 c->delayed = 0; 2562 else 2563 continue; 2564 } 2565 if (ftab[c->type] != NULL) { 2566 if (table == CHAN_PRE && 2567 c->type == SSH_CHANNEL_OPEN && 2568 c->inactive_deadline != 0 && c->lastused != 0 && 2569 now >= c->lastused + c->inactive_deadline) { 2570 /* channel closed for inactivity */ 2571 verbose("channel %d: closing after %u seconds " 2572 "of inactivity", c->self, 2573 c->inactive_deadline); 2574 channel_force_close(ssh, c, 1); 2575 } else if (c->notbefore <= now) { 2576 /* Run handlers that are not paused. */ 2577 (*ftab[c->type])(ssh, c); 2578 /* inactivity timeouts must interrupt poll() */ 2579 if (timeout != NULL && 2580 c->type == SSH_CHANNEL_OPEN && 2581 c->lastused != 0 && 2582 c->inactive_deadline != 0) { 2583 ptimeout_deadline_monotime(timeout, 2584 c->lastused + c->inactive_deadline); 2585 } 2586 } else if (timeout != NULL) { 2587 /* 2588 * Arrange for poll() wakeup when channel pause 2589 * timer expires. 2590 */ 2591 ptimeout_deadline_monotime(timeout, 2592 c->notbefore); 2593 } 2594 } 2595 channel_garbage_collect(ssh, c); 2596 } 2597 } 2598 2599 /* 2600 * Create sockets before preparing IO. 2601 * This is necessary for things that need to happen after reading 2602 * the network-input but need to be completed before IO event setup, e.g. 2603 * because they may create new channels. 2604 */ 2605 static void 2606 channel_before_prepare_io(struct ssh *ssh) 2607 { 2608 struct ssh_channels *sc = ssh->chanctxt; 2609 Channel *c; 2610 u_int i, oalloc; 2611 2612 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2613 c = sc->channels[i]; 2614 if (c == NULL) 2615 continue; 2616 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2617 channel_before_prepare_io_rdynamic(ssh, c); 2618 } 2619 } 2620 2621 static void 2622 dump_channel_poll(const char *func, const char *what, Channel *c, 2623 u_int pollfd_offset, struct pollfd *pfd) 2624 { 2625 #ifdef DEBUG_CHANNEL_POLL 2626 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2627 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2628 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2629 c->rfd, c->wfd, c->efd, c->sock, 2630 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2631 c->io_want, c->io_ready, 2632 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2633 #endif 2634 } 2635 2636 /* Prepare pollfd entries for a single channel */ 2637 static void 2638 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2639 struct pollfd *pfd, u_int npfd) 2640 { 2641 u_int ev, p = *next_pollfd; 2642 2643 if (c == NULL) 2644 return; 2645 if (p + 4 > npfd) { 2646 /* Shouldn't happen */ 2647 fatal_f("channel %d: bad pfd offset %u (max %u)", 2648 c->self, p, npfd); 2649 } 2650 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2651 /* 2652 * prepare c->rfd 2653 * 2654 * This is a special case, since c->rfd might be the same as 2655 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2656 * IO too. 2657 */ 2658 if (c->rfd != -1) { 2659 ev = 0; 2660 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2661 ev |= POLLIN; 2662 /* rfd == wfd */ 2663 if (c->wfd == c->rfd) { 2664 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2665 ev |= POLLOUT; 2666 } 2667 /* rfd == efd */ 2668 if (c->efd == c->rfd) { 2669 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2670 ev |= POLLIN; 2671 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2672 ev |= POLLOUT; 2673 } 2674 /* rfd == sock */ 2675 if (c->sock == c->rfd) { 2676 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2677 ev |= POLLIN; 2678 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2679 ev |= POLLOUT; 2680 } 2681 /* Pack a pfd entry if any event armed for this fd */ 2682 if (ev != 0) { 2683 c->pfds[0] = p; 2684 pfd[p].fd = c->rfd; 2685 pfd[p].events = ev; 2686 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2687 p++; 2688 } 2689 } 2690 /* prepare c->wfd if wanting IO and not already handled above */ 2691 if (c->wfd != -1 && c->rfd != c->wfd) { 2692 ev = 0; 2693 if ((c->io_want & SSH_CHAN_IO_WFD)) 2694 ev |= POLLOUT; 2695 /* Pack a pfd entry if any event armed for this fd */ 2696 if (ev != 0) { 2697 c->pfds[1] = p; 2698 pfd[p].fd = c->wfd; 2699 pfd[p].events = ev; 2700 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2701 p++; 2702 } 2703 } 2704 /* prepare c->efd if wanting IO and not already handled above */ 2705 if (c->efd != -1 && c->rfd != c->efd) { 2706 ev = 0; 2707 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2708 ev |= POLLIN; 2709 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2710 ev |= POLLOUT; 2711 /* Pack a pfd entry if any event armed for this fd */ 2712 if (ev != 0) { 2713 c->pfds[2] = p; 2714 pfd[p].fd = c->efd; 2715 pfd[p].events = ev; 2716 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2717 p++; 2718 } 2719 } 2720 /* prepare c->sock if wanting IO and not already handled above */ 2721 if (c->sock != -1 && c->rfd != c->sock) { 2722 ev = 0; 2723 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2724 ev |= POLLIN; 2725 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2726 ev |= POLLOUT; 2727 /* Pack a pfd entry if any event armed for this fd */ 2728 if (ev != 0) { 2729 c->pfds[3] = p; 2730 pfd[p].fd = c->sock; 2731 pfd[p].events = 0; 2732 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2733 p++; 2734 } 2735 } 2736 *next_pollfd = p; 2737 } 2738 2739 /* * Allocate/prepare poll structure */ 2740 void 2741 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2742 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2743 { 2744 struct ssh_channels *sc = ssh->chanctxt; 2745 u_int i, oalloc, p, npfd = npfd_reserved; 2746 2747 channel_before_prepare_io(ssh); /* might create a new channel */ 2748 /* clear out I/O flags from last poll */ 2749 for (i = 0; i < sc->channels_alloc; i++) { 2750 if (sc->channels[i] == NULL) 2751 continue; 2752 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2753 } 2754 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2755 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2756 fatal_f("too many channels"); /* shouldn't happen */ 2757 npfd += sc->channels_alloc * 4; 2758 if (npfd > *npfd_allocp) { 2759 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2760 npfd, sizeof(**pfdp)); 2761 *npfd_allocp = npfd; 2762 } 2763 *npfd_activep = npfd_reserved; 2764 oalloc = sc->channels_alloc; 2765 2766 channel_handler(ssh, CHAN_PRE, timeout); 2767 2768 if (oalloc != sc->channels_alloc) { 2769 /* shouldn't happen */ 2770 fatal_f("channels_alloc changed during CHAN_PRE " 2771 "(was %u, now %u)", oalloc, sc->channels_alloc); 2772 } 2773 2774 /* Prepare pollfd */ 2775 p = npfd_reserved; 2776 for (i = 0; i < sc->channels_alloc; i++) 2777 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2778 *npfd_activep = p; 2779 } 2780 2781 static void 2782 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2783 const char *what, u_int revents_mask, u_int ready) 2784 { 2785 struct pollfd *pfd = &pfds[p]; 2786 2787 if (fd == -1) 2788 return; 2789 if (p == -1 || (u_int)p >= npfd) 2790 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2791 dump_channel_poll(__func__, what, c, p, pfd); 2792 if (pfd->fd != fd) { 2793 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2794 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2795 c->rfd, c->wfd, c->efd, c->sock); 2796 } 2797 if ((pfd->revents & POLLNVAL) != 0) { 2798 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2799 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2800 } 2801 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2802 c->io_ready |= ready & c->io_want; 2803 } 2804 2805 /* 2806 * After poll, perform any appropriate operations for channels which have 2807 * events pending. 2808 */ 2809 void 2810 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2811 { 2812 struct ssh_channels *sc = ssh->chanctxt; 2813 u_int i; 2814 int p; 2815 Channel *c; 2816 2817 #ifdef DEBUG_CHANNEL_POLL 2818 for (p = 0; p < (int)npfd; p++) { 2819 if (pfd[p].revents == 0) 2820 continue; 2821 debug_f("pfd[%u].fd %d rev 0x%04x", 2822 p, pfd[p].fd, pfd[p].revents); 2823 } 2824 #endif 2825 2826 /* Convert pollfd into c->io_ready */ 2827 for (i = 0; i < sc->channels_alloc; i++) { 2828 c = sc->channels[i]; 2829 if (c == NULL) 2830 continue; 2831 /* if rfd is shared with efd/sock then wfd should be too */ 2832 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2833 (c->rfd == c->efd || c->rfd == c->sock)) { 2834 /* Shouldn't happen */ 2835 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2836 c->self, c->rfd, c->wfd, c->efd, c->sock); 2837 } 2838 c->io_ready = 0; 2839 /* rfd, potentially shared with wfd, efd and sock */ 2840 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2841 fd_ready(c, p, pfd, npfd, c->rfd, 2842 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2843 if (c->rfd == c->wfd) { 2844 fd_ready(c, p, pfd, npfd, c->wfd, 2845 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2846 } 2847 if (c->rfd == c->efd) { 2848 fd_ready(c, p, pfd, npfd, c->efd, 2849 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2850 fd_ready(c, p, pfd, npfd, c->efd, 2851 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2852 } 2853 if (c->rfd == c->sock) { 2854 fd_ready(c, p, pfd, npfd, c->sock, 2855 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2856 fd_ready(c, p, pfd, npfd, c->sock, 2857 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2858 } 2859 dump_channel_poll(__func__, "rfd", c, p, pfd); 2860 } 2861 /* wfd */ 2862 if (c->wfd != -1 && c->wfd != c->rfd && 2863 (p = c->pfds[1]) != -1) { 2864 fd_ready(c, p, pfd, npfd, c->wfd, 2865 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2866 dump_channel_poll(__func__, "wfd", c, p, pfd); 2867 } 2868 /* efd */ 2869 if (c->efd != -1 && c->efd != c->rfd && 2870 (p = c->pfds[2]) != -1) { 2871 fd_ready(c, p, pfd, npfd, c->efd, 2872 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2873 fd_ready(c, p, pfd, npfd, c->efd, 2874 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2875 dump_channel_poll(__func__, "efd", c, p, pfd); 2876 } 2877 /* sock */ 2878 if (c->sock != -1 && c->sock != c->rfd && 2879 (p = c->pfds[3]) != -1) { 2880 fd_ready(c, p, pfd, npfd, c->sock, 2881 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2882 fd_ready(c, p, pfd, npfd, c->sock, 2883 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2884 dump_channel_poll(__func__, "sock", c, p, pfd); 2885 } 2886 } 2887 channel_handler(ssh, CHAN_POST, NULL); 2888 } 2889 2890 /* 2891 * Enqueue data for channels with open or draining c->input. 2892 */ 2893 static void 2894 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2895 { 2896 size_t len, plen; 2897 const u_char *pkt; 2898 int r; 2899 2900 if ((len = sshbuf_len(c->input)) == 0) { 2901 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2902 /* 2903 * input-buffer is empty and read-socket shutdown: 2904 * tell peer, that we will not send more data: 2905 * send IEOF. 2906 * hack for extended data: delay EOF if EFD still 2907 * in use. 2908 */ 2909 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2910 debug2("channel %d: " 2911 "ibuf_empty delayed efd %d/(%zu)", 2912 c->self, c->efd, sshbuf_len(c->extended)); 2913 else 2914 chan_ibuf_empty(ssh, c); 2915 } 2916 return; 2917 } 2918 2919 if (!c->have_remote_id) 2920 fatal_f("channel %d: no remote id", c->self); 2921 2922 if (c->datagram) { 2923 /* Check datagram will fit; drop if not */ 2924 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2925 fatal_fr(r, "channel %i: get datagram", c->self); 2926 /* 2927 * XXX this does tail-drop on the datagram queue which is 2928 * usually suboptimal compared to head-drop. Better to have 2929 * backpressure at read time? (i.e. read + discard) 2930 */ 2931 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2932 debug("channel %d: datagram too big", c->self); 2933 return; 2934 } 2935 /* Enqueue it */ 2936 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2937 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2938 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2939 (r = sshpkt_send(ssh)) != 0) 2940 fatal_fr(r, "channel %i: send datagram", c->self); 2941 c->remote_window -= plen; 2942 return; 2943 } 2944 2945 /* Enqueue packet for buffered data. */ 2946 if (len > c->remote_window) 2947 len = c->remote_window; 2948 if (len > c->remote_maxpacket) 2949 len = c->remote_maxpacket; 2950 if (len == 0) 2951 return; 2952 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2953 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2954 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2955 (r = sshpkt_send(ssh)) != 0) 2956 fatal_fr(r, "channel %i: send data", c->self); 2957 if ((r = sshbuf_consume(c->input, len)) != 0) 2958 fatal_fr(r, "channel %i: consume", c->self); 2959 c->remote_window -= len; 2960 } 2961 2962 /* 2963 * Enqueue data for channels with open c->extended in read mode. 2964 */ 2965 static void 2966 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2967 { 2968 size_t len; 2969 int r; 2970 2971 if ((len = sshbuf_len(c->extended)) == 0) 2972 return; 2973 2974 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2975 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2976 if (len > c->remote_window) 2977 len = c->remote_window; 2978 if (len > c->remote_maxpacket) 2979 len = c->remote_maxpacket; 2980 if (len == 0) 2981 return; 2982 if (!c->have_remote_id) 2983 fatal_f("channel %d: no remote id", c->self); 2984 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2985 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2986 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2987 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2988 (r = sshpkt_send(ssh)) != 0) 2989 fatal_fr(r, "channel %i: data", c->self); 2990 if ((r = sshbuf_consume(c->extended, len)) != 0) 2991 fatal_fr(r, "channel %i: consume", c->self); 2992 c->remote_window -= len; 2993 debug2("channel %d: sent ext data %zu", c->self, len); 2994 } 2995 2996 /* If there is data to send to the connection, enqueue some of it now. */ 2997 void 2998 channel_output_poll(struct ssh *ssh) 2999 { 3000 struct ssh_channels *sc = ssh->chanctxt; 3001 Channel *c; 3002 u_int i; 3003 3004 for (i = 0; i < sc->channels_alloc; i++) { 3005 c = sc->channels[i]; 3006 if (c == NULL) 3007 continue; 3008 3009 /* 3010 * We are only interested in channels that can have buffered 3011 * incoming data. 3012 */ 3013 if (c->type != SSH_CHANNEL_OPEN) 3014 continue; 3015 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3016 /* XXX is this true? */ 3017 debug3("channel %d: will not send data after close", 3018 c->self); 3019 continue; 3020 } 3021 3022 /* Get the amount of buffered data for this channel. */ 3023 if (c->istate == CHAN_INPUT_OPEN || 3024 c->istate == CHAN_INPUT_WAIT_DRAIN) 3025 channel_output_poll_input_open(ssh, c); 3026 /* Send extended data, i.e. stderr */ 3027 if (!(c->flags & CHAN_EOF_SENT) && 3028 c->extended_usage == CHAN_EXTENDED_READ) 3029 channel_output_poll_extended_read(ssh, c); 3030 } 3031 } 3032 3033 /* -- mux proxy support */ 3034 3035 /* 3036 * When multiplexing channel messages for mux clients we have to deal 3037 * with downstream messages from the mux client and upstream messages 3038 * from the ssh server: 3039 * 1) Handling downstream messages is straightforward and happens 3040 * in channel_proxy_downstream(): 3041 * - We forward all messages (mostly) unmodified to the server. 3042 * - However, in order to route messages from upstream to the correct 3043 * downstream client, we have to replace the channel IDs used by the 3044 * mux clients with a unique channel ID because the mux clients might 3045 * use conflicting channel IDs. 3046 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3047 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3048 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3049 * with the newly allocated channel ID. 3050 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3051 * channels and processed by channel_proxy_upstream(). The local channel ID 3052 * is then translated back to the original mux client ID. 3053 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3054 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3055 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3056 * downstream mux client are removed. 3057 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3058 * requires more work, because they are not addressed to a specific 3059 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3060 * out whether the request is addressed to the local client or a 3061 * specific downstream client based on the listen-address/port. 3062 * 6) Agent and X11-Forwarding have a similar problem and are currently 3063 * not supported as the matching session/channel cannot be identified 3064 * easily. 3065 */ 3066 3067 /* 3068 * receive packets from downstream mux clients: 3069 * channel callback fired on read from mux client, creates 3070 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3071 * on channel creation. 3072 */ 3073 int 3074 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3075 { 3076 Channel *c = NULL; 3077 struct sshbuf *original = NULL, *modified = NULL; 3078 const u_char *cp; 3079 char *ctype = NULL, *listen_host = NULL; 3080 u_char type; 3081 size_t have; 3082 int ret = -1, r; 3083 u_int id, remote_id, listen_port; 3084 3085 /* sshbuf_dump(downstream->input, stderr); */ 3086 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3087 != 0) { 3088 error_fr(r, "parse"); 3089 return -1; 3090 } 3091 if (have < 2) { 3092 error_f("short message"); 3093 return -1; 3094 } 3095 type = cp[1]; 3096 /* skip padlen + type */ 3097 cp += 2; 3098 have -= 2; 3099 if (ssh_packet_log_type(type)) 3100 debug3_f("channel %u: down->up: type %u", 3101 downstream->self, type); 3102 3103 switch (type) { 3104 case SSH2_MSG_CHANNEL_OPEN: 3105 if ((original = sshbuf_from(cp, have)) == NULL || 3106 (modified = sshbuf_new()) == NULL) { 3107 error_f("alloc"); 3108 goto out; 3109 } 3110 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3111 (r = sshbuf_get_u32(original, &id)) != 0) { 3112 error_fr(r, "parse"); 3113 goto out; 3114 } 3115 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3116 -1, -1, -1, 0, 0, 0, ctype, 1); 3117 c->mux_ctx = downstream; /* point to mux client */ 3118 c->mux_downstream_id = id; /* original downstream id */ 3119 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3120 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3121 (r = sshbuf_putb(modified, original)) != 0) { 3122 error_fr(r, "compose"); 3123 channel_free(ssh, c); 3124 goto out; 3125 } 3126 break; 3127 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3128 /* 3129 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3130 * need to parse 'remote_id' instead of 'ctype'. 3131 */ 3132 if ((original = sshbuf_from(cp, have)) == NULL || 3133 (modified = sshbuf_new()) == NULL) { 3134 error_f("alloc"); 3135 goto out; 3136 } 3137 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3138 (r = sshbuf_get_u32(original, &id)) != 0) { 3139 error_fr(r, "parse"); 3140 goto out; 3141 } 3142 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3143 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3144 c->mux_ctx = downstream; /* point to mux client */ 3145 c->mux_downstream_id = id; 3146 c->remote_id = remote_id; 3147 c->have_remote_id = 1; 3148 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3149 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3150 (r = sshbuf_putb(modified, original)) != 0) { 3151 error_fr(r, "compose"); 3152 channel_free(ssh, c); 3153 goto out; 3154 } 3155 break; 3156 case SSH2_MSG_GLOBAL_REQUEST: 3157 if ((original = sshbuf_from(cp, have)) == NULL) { 3158 error_f("alloc"); 3159 goto out; 3160 } 3161 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3162 error_fr(r, "parse"); 3163 goto out; 3164 } 3165 if (strcmp(ctype, "tcpip-forward") != 0) { 3166 error_f("unsupported request %s", ctype); 3167 goto out; 3168 } 3169 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3170 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3171 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3172 error_fr(r, "parse"); 3173 goto out; 3174 } 3175 if (listen_port > 65535) { 3176 error_f("tcpip-forward for %s: bad port %u", 3177 listen_host, listen_port); 3178 goto out; 3179 } 3180 /* Record that connection to this host/port is permitted. */ 3181 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 3182 listen_host, NULL, (int)listen_port, downstream); 3183 listen_host = NULL; 3184 break; 3185 case SSH2_MSG_CHANNEL_CLOSE: 3186 if (have < 4) 3187 break; 3188 remote_id = PEEK_U32(cp); 3189 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3190 if (c->flags & CHAN_CLOSE_RCVD) 3191 channel_free(ssh, c); 3192 else 3193 c->flags |= CHAN_CLOSE_SENT; 3194 } 3195 break; 3196 } 3197 if (modified) { 3198 if ((r = sshpkt_start(ssh, type)) != 0 || 3199 (r = sshpkt_putb(ssh, modified)) != 0 || 3200 (r = sshpkt_send(ssh)) != 0) { 3201 error_fr(r, "send"); 3202 goto out; 3203 } 3204 } else { 3205 if ((r = sshpkt_start(ssh, type)) != 0 || 3206 (r = sshpkt_put(ssh, cp, have)) != 0 || 3207 (r = sshpkt_send(ssh)) != 0) { 3208 error_fr(r, "send"); 3209 goto out; 3210 } 3211 } 3212 ret = 0; 3213 out: 3214 free(ctype); 3215 free(listen_host); 3216 sshbuf_free(original); 3217 sshbuf_free(modified); 3218 return ret; 3219 } 3220 3221 /* 3222 * receive packets from upstream server and de-multiplex packets 3223 * to correct downstream: 3224 * implemented as a helper for channel input handlers, 3225 * replaces local (proxy) channel ID with downstream channel ID. 3226 */ 3227 int 3228 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3229 { 3230 struct sshbuf *b = NULL; 3231 Channel *downstream; 3232 const u_char *cp = NULL; 3233 size_t len; 3234 int r; 3235 3236 /* 3237 * When receiving packets from the peer we need to check whether we 3238 * need to forward the packets to the mux client. In this case we 3239 * restore the original channel id and keep track of CLOSE messages, 3240 * so we can cleanup the channel. 3241 */ 3242 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3243 return 0; 3244 if ((downstream = c->mux_ctx) == NULL) 3245 return 0; 3246 switch (type) { 3247 case SSH2_MSG_CHANNEL_CLOSE: 3248 case SSH2_MSG_CHANNEL_DATA: 3249 case SSH2_MSG_CHANNEL_EOF: 3250 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3251 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3252 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3253 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3254 case SSH2_MSG_CHANNEL_SUCCESS: 3255 case SSH2_MSG_CHANNEL_FAILURE: 3256 case SSH2_MSG_CHANNEL_REQUEST: 3257 break; 3258 default: 3259 debug2_f("channel %u: unsupported type %u", c->self, type); 3260 return 0; 3261 } 3262 if ((b = sshbuf_new()) == NULL) { 3263 error_f("alloc reply"); 3264 goto out; 3265 } 3266 /* get remaining payload (after id) */ 3267 cp = sshpkt_ptr(ssh, &len); 3268 if (cp == NULL) { 3269 error_f("no packet"); 3270 goto out; 3271 } 3272 /* translate id and send to muxclient */ 3273 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3274 (r = sshbuf_put_u8(b, type)) != 0 || 3275 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3276 (r = sshbuf_put(b, cp, len)) != 0 || 3277 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3278 error_fr(r, "compose muxclient"); 3279 goto out; 3280 } 3281 /* sshbuf_dump(b, stderr); */ 3282 if (ssh_packet_log_type(type)) 3283 debug3_f("channel %u: up->down: type %u", c->self, type); 3284 out: 3285 /* update state */ 3286 switch (type) { 3287 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3288 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3289 if (cp && len > 4) { 3290 c->remote_id = PEEK_U32(cp); 3291 c->have_remote_id = 1; 3292 } 3293 break; 3294 case SSH2_MSG_CHANNEL_CLOSE: 3295 if (c->flags & CHAN_CLOSE_SENT) 3296 channel_free(ssh, c); 3297 else 3298 c->flags |= CHAN_CLOSE_RCVD; 3299 break; 3300 } 3301 sshbuf_free(b); 3302 return 1; 3303 } 3304 3305 /* -- protocol input */ 3306 3307 /* Parse a channel ID from the current packet */ 3308 static int 3309 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3310 { 3311 u_int32_t id; 3312 int r; 3313 3314 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3315 error_r(r, "%s: parse id", where); 3316 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3317 } 3318 if (id > INT_MAX) { 3319 error_r(r, "%s: bad channel id %u", where, id); 3320 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3321 } 3322 return (int)id; 3323 } 3324 3325 /* Lookup a channel from an ID in the current packet */ 3326 static Channel * 3327 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3328 { 3329 int id = channel_parse_id(ssh, where, what); 3330 Channel *c; 3331 3332 if ((c = channel_lookup(ssh, id)) == NULL) { 3333 ssh_packet_disconnect(ssh, 3334 "%s packet referred to nonexistent channel %d", what, id); 3335 } 3336 return c; 3337 } 3338 3339 int 3340 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3341 { 3342 const u_char *data; 3343 size_t data_len, win_len; 3344 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3345 int r; 3346 3347 if (channel_proxy_upstream(c, type, seq, ssh)) 3348 return 0; 3349 3350 /* Ignore any data for non-open channels (might happen on close) */ 3351 if (c->type != SSH_CHANNEL_OPEN && 3352 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3353 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3354 c->type != SSH_CHANNEL_X11_OPEN) 3355 return 0; 3356 3357 /* Get the data. */ 3358 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3359 (r = sshpkt_get_end(ssh)) != 0) 3360 fatal_fr(r, "channel %i: get data", c->self); 3361 3362 win_len = data_len; 3363 if (c->datagram) 3364 win_len += 4; /* string length header */ 3365 3366 /* 3367 * The sending side reduces its window as it sends data, so we 3368 * must 'fake' consumption of the data in order to ensure that window 3369 * updates are sent back. Otherwise the connection might deadlock. 3370 */ 3371 if (c->ostate != CHAN_OUTPUT_OPEN) { 3372 c->local_window -= win_len; 3373 c->local_consumed += win_len; 3374 return 0; 3375 } 3376 3377 if (win_len > c->local_maxpacket) { 3378 logit("channel %d: rcvd big packet %zu, maxpack %u", 3379 c->self, win_len, c->local_maxpacket); 3380 return 0; 3381 } 3382 if (win_len > c->local_window) { 3383 logit("channel %d: rcvd too much data %zu, win %u", 3384 c->self, win_len, c->local_window); 3385 return 0; 3386 } 3387 c->local_window -= win_len; 3388 3389 if (c->datagram) { 3390 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3391 fatal_fr(r, "channel %i: append datagram", c->self); 3392 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3393 fatal_fr(r, "channel %i: append data", c->self); 3394 3395 return 0; 3396 } 3397 3398 int 3399 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3400 { 3401 const u_char *data; 3402 size_t data_len; 3403 u_int32_t tcode; 3404 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3405 int r; 3406 3407 if (channel_proxy_upstream(c, type, seq, ssh)) 3408 return 0; 3409 if (c->type != SSH_CHANNEL_OPEN) { 3410 logit("channel %d: ext data for non open", c->self); 3411 return 0; 3412 } 3413 if (c->flags & CHAN_EOF_RCVD) { 3414 if (ssh->compat & SSH_BUG_EXTEOF) 3415 debug("channel %d: accepting ext data after eof", 3416 c->self); 3417 else 3418 ssh_packet_disconnect(ssh, "Received extended_data " 3419 "after EOF on channel %d.", c->self); 3420 } 3421 3422 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3423 error_fr(r, "parse tcode"); 3424 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3425 } 3426 if (c->efd == -1 || 3427 c->extended_usage != CHAN_EXTENDED_WRITE || 3428 tcode != SSH2_EXTENDED_DATA_STDERR) { 3429 logit("channel %d: bad ext data", c->self); 3430 return 0; 3431 } 3432 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3433 (r = sshpkt_get_end(ssh)) != 0) { 3434 error_fr(r, "parse data"); 3435 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3436 } 3437 3438 if (data_len > c->local_window) { 3439 logit("channel %d: rcvd too much extended_data %zu, win %u", 3440 c->self, data_len, c->local_window); 3441 return 0; 3442 } 3443 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3444 /* XXX sshpkt_getb? */ 3445 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3446 error_fr(r, "append"); 3447 c->local_window -= data_len; 3448 return 0; 3449 } 3450 3451 int 3452 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3453 { 3454 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3455 int r; 3456 3457 if ((r = sshpkt_get_end(ssh)) != 0) { 3458 error_fr(r, "parse data"); 3459 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3460 } 3461 3462 if (channel_proxy_upstream(c, type, seq, ssh)) 3463 return 0; 3464 chan_rcvd_ieof(ssh, c); 3465 3466 /* XXX force input close */ 3467 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3468 debug("channel %d: FORCE input drain", c->self); 3469 c->istate = CHAN_INPUT_WAIT_DRAIN; 3470 if (sshbuf_len(c->input) == 0) 3471 chan_ibuf_empty(ssh, c); 3472 } 3473 return 0; 3474 } 3475 3476 int 3477 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3478 { 3479 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3480 int r; 3481 3482 if (channel_proxy_upstream(c, type, seq, ssh)) 3483 return 0; 3484 if ((r = sshpkt_get_end(ssh)) != 0) { 3485 error_fr(r, "parse data"); 3486 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3487 } 3488 chan_rcvd_oclose(ssh, c); 3489 return 0; 3490 } 3491 3492 int 3493 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3494 { 3495 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3496 u_int32_t remote_window, remote_maxpacket; 3497 int r; 3498 3499 if (channel_proxy_upstream(c, type, seq, ssh)) 3500 return 0; 3501 if (c->type != SSH_CHANNEL_OPENING) 3502 ssh_packet_disconnect(ssh, "Received open confirmation for " 3503 "non-opening channel %d.", c->self); 3504 /* 3505 * Record the remote channel number and mark that the channel 3506 * is now open. 3507 */ 3508 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3509 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3510 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3511 (r = sshpkt_get_end(ssh)) != 0) { 3512 error_fr(r, "window/maxpacket"); 3513 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3514 } 3515 3516 c->have_remote_id = 1; 3517 c->remote_window = remote_window; 3518 c->remote_maxpacket = remote_maxpacket; 3519 c->type = SSH_CHANNEL_OPEN; 3520 if (c->open_confirm) { 3521 debug2_f("channel %d: callback start", c->self); 3522 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3523 debug2_f("channel %d: callback done", c->self); 3524 } 3525 c->lastused = monotime(); 3526 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3527 c->remote_window, c->remote_maxpacket); 3528 return 0; 3529 } 3530 3531 static char * 3532 reason2txt(int reason) 3533 { 3534 switch (reason) { 3535 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3536 return "administratively prohibited"; 3537 case SSH2_OPEN_CONNECT_FAILED: 3538 return "connect failed"; 3539 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3540 return "unknown channel type"; 3541 case SSH2_OPEN_RESOURCE_SHORTAGE: 3542 return "resource shortage"; 3543 } 3544 return "unknown reason"; 3545 } 3546 3547 int 3548 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3549 { 3550 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3551 u_int32_t reason; 3552 char *msg = NULL; 3553 int r; 3554 3555 if (channel_proxy_upstream(c, type, seq, ssh)) 3556 return 0; 3557 if (c->type != SSH_CHANNEL_OPENING) 3558 ssh_packet_disconnect(ssh, "Received open failure for " 3559 "non-opening channel %d.", c->self); 3560 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3561 error_fr(r, "parse reason"); 3562 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3563 } 3564 /* skip language */ 3565 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3566 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3567 (r = sshpkt_get_end(ssh)) != 0) { 3568 error_fr(r, "parse msg/lang"); 3569 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3570 } 3571 logit("channel %d: open failed: %s%s%s", c->self, 3572 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3573 free(msg); 3574 if (c->open_confirm) { 3575 debug2_f("channel %d: callback start", c->self); 3576 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3577 debug2_f("channel %d: callback done", c->self); 3578 } 3579 /* Schedule the channel for cleanup/deletion. */ 3580 chan_mark_dead(ssh, c); 3581 return 0; 3582 } 3583 3584 int 3585 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3586 { 3587 int id = channel_parse_id(ssh, __func__, "window adjust"); 3588 Channel *c; 3589 u_int32_t adjust; 3590 u_int new_rwin; 3591 int r; 3592 3593 if ((c = channel_lookup(ssh, id)) == NULL) { 3594 logit("Received window adjust for non-open channel %d.", id); 3595 return 0; 3596 } 3597 3598 if (channel_proxy_upstream(c, type, seq, ssh)) 3599 return 0; 3600 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3601 (r = sshpkt_get_end(ssh)) != 0) { 3602 error_fr(r, "parse adjust"); 3603 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3604 } 3605 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3606 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3607 fatal("channel %d: adjust %u overflows remote window %u", 3608 c->self, adjust, c->remote_window); 3609 } 3610 c->remote_window = new_rwin; 3611 return 0; 3612 } 3613 3614 int 3615 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3616 { 3617 int id = channel_parse_id(ssh, __func__, "status confirm"); 3618 Channel *c; 3619 struct channel_confirm *cc; 3620 3621 /* Reset keepalive timeout */ 3622 ssh_packet_set_alive_timeouts(ssh, 0); 3623 3624 debug2_f("type %d id %d", type, id); 3625 3626 if ((c = channel_lookup(ssh, id)) == NULL) { 3627 logit_f("%d: unknown", id); 3628 return 0; 3629 } 3630 if (channel_proxy_upstream(c, type, seq, ssh)) 3631 return 0; 3632 if (sshpkt_get_end(ssh) != 0) 3633 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3634 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3635 return 0; 3636 cc->cb(ssh, type, c, cc->ctx); 3637 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3638 freezero(cc, sizeof(*cc)); 3639 return 0; 3640 } 3641 3642 /* -- tcp forwarding */ 3643 3644 void 3645 channel_set_af(struct ssh *ssh, int af) 3646 { 3647 ssh->chanctxt->IPv4or6 = af; 3648 } 3649 3650 3651 /* 3652 * Determine whether or not a port forward listens to loopback, the 3653 * specified address or wildcard. On the client, a specified bind 3654 * address will always override gateway_ports. On the server, a 3655 * gateway_ports of 1 (``yes'') will override the client's specification 3656 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3657 * will bind to whatever address the client asked for. 3658 * 3659 * Special-case listen_addrs are: 3660 * 3661 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3662 * "" (empty string), "*" -> wildcard v4/v6 3663 * "localhost" -> loopback v4/v6 3664 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3665 */ 3666 static const char * 3667 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3668 int is_client, struct ForwardOptions *fwd_opts) 3669 { 3670 const char *addr = NULL; 3671 int wildcard = 0; 3672 3673 if (listen_addr == NULL) { 3674 /* No address specified: default to gateway_ports setting */ 3675 if (fwd_opts->gateway_ports) 3676 wildcard = 1; 3677 } else if (fwd_opts->gateway_ports || is_client) { 3678 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3679 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3680 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3681 (!is_client && fwd_opts->gateway_ports == 1)) { 3682 wildcard = 1; 3683 /* 3684 * Notify client if they requested a specific listen 3685 * address and it was overridden. 3686 */ 3687 if (*listen_addr != '\0' && 3688 strcmp(listen_addr, "0.0.0.0") != 0 && 3689 strcmp(listen_addr, "*") != 0) { 3690 ssh_packet_send_debug(ssh, 3691 "Forwarding listen address " 3692 "\"%s\" overridden by server " 3693 "GatewayPorts", listen_addr); 3694 } 3695 } else if (strcmp(listen_addr, "localhost") != 0 || 3696 strcmp(listen_addr, "127.0.0.1") == 0 || 3697 strcmp(listen_addr, "::1") == 0) { 3698 /* 3699 * Accept explicit localhost address when 3700 * GatewayPorts=yes. The "localhost" hostname is 3701 * deliberately skipped here so it will listen on all 3702 * available local address families. 3703 */ 3704 addr = listen_addr; 3705 } 3706 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3707 strcmp(listen_addr, "::1") == 0) { 3708 /* 3709 * If a specific IPv4/IPv6 localhost address has been 3710 * requested then accept it even if gateway_ports is in 3711 * effect. This allows the client to prefer IPv4 or IPv6. 3712 */ 3713 addr = listen_addr; 3714 } 3715 if (wildcardp != NULL) 3716 *wildcardp = wildcard; 3717 return addr; 3718 } 3719 3720 static int 3721 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3722 struct Forward *fwd, int *allocated_listen_port, 3723 struct ForwardOptions *fwd_opts) 3724 { 3725 Channel *c; 3726 int sock, r, success = 0, wildcard = 0, is_client; 3727 struct addrinfo hints, *ai, *aitop; 3728 const char *host, *addr; 3729 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3730 in_port_t *lport_p; 3731 3732 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3733 3734 if (is_client && fwd->connect_path != NULL) { 3735 host = fwd->connect_path; 3736 } else { 3737 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3738 fwd->listen_host : fwd->connect_host; 3739 if (host == NULL) { 3740 error("No forward host name."); 3741 return 0; 3742 } 3743 if (strlen(host) >= NI_MAXHOST) { 3744 error("Forward host name too long."); 3745 return 0; 3746 } 3747 } 3748 3749 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3750 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3751 is_client, fwd_opts); 3752 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3753 (addr == NULL) ? "NULL" : addr); 3754 3755 /* 3756 * getaddrinfo returns a loopback address if the hostname is 3757 * set to NULL and hints.ai_flags is not AI_PASSIVE 3758 */ 3759 memset(&hints, 0, sizeof(hints)); 3760 hints.ai_family = ssh->chanctxt->IPv4or6; 3761 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3762 hints.ai_socktype = SOCK_STREAM; 3763 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3764 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3765 if (addr == NULL) { 3766 /* This really shouldn't happen */ 3767 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3768 ssh_gai_strerror(r)); 3769 } else { 3770 error_f("getaddrinfo(%.64s): %s", addr, 3771 ssh_gai_strerror(r)); 3772 } 3773 return 0; 3774 } 3775 if (allocated_listen_port != NULL) 3776 *allocated_listen_port = 0; 3777 for (ai = aitop; ai; ai = ai->ai_next) { 3778 switch (ai->ai_family) { 3779 case AF_INET: 3780 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3781 sin_port; 3782 break; 3783 case AF_INET6: 3784 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3785 sin6_port; 3786 break; 3787 default: 3788 continue; 3789 } 3790 /* 3791 * If allocating a port for -R forwards, then use the 3792 * same port for all address families. 3793 */ 3794 if (type == SSH_CHANNEL_RPORT_LISTENER && 3795 fwd->listen_port == 0 && allocated_listen_port != NULL && 3796 *allocated_listen_port > 0) 3797 *lport_p = htons(*allocated_listen_port); 3798 3799 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3800 strport, sizeof(strport), 3801 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3802 error_f("getnameinfo failed"); 3803 continue; 3804 } 3805 /* Create a port to listen for the host. */ 3806 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3807 if (sock == -1) { 3808 /* this is no error since kernel may not support ipv6 */ 3809 verbose("socket [%s]:%s: %.100s", ntop, strport, 3810 strerror(errno)); 3811 continue; 3812 } 3813 3814 set_reuseaddr(sock); 3815 if (ai->ai_family == AF_INET6) 3816 sock_set_v6only(sock); 3817 3818 debug("Local forwarding listening on %s port %s.", 3819 ntop, strport); 3820 3821 /* Bind the socket to the address. */ 3822 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3823 /* 3824 * address can be in if use ipv6 address is 3825 * already bound 3826 */ 3827 if (!ai->ai_next) 3828 error("bind [%s]:%s: %.100s", 3829 ntop, strport, strerror(errno)); 3830 else 3831 verbose("bind [%s]:%s: %.100s", 3832 ntop, strport, strerror(errno)); 3833 3834 close(sock); 3835 continue; 3836 } 3837 /* Start listening for connections on the socket. */ 3838 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3839 error("listen [%s]:%s: %.100s", ntop, strport, 3840 strerror(errno)); 3841 close(sock); 3842 continue; 3843 } 3844 3845 /* 3846 * fwd->listen_port == 0 requests a dynamically allocated port - 3847 * record what we got. 3848 */ 3849 if (type == SSH_CHANNEL_RPORT_LISTENER && 3850 fwd->listen_port == 0 && 3851 allocated_listen_port != NULL && 3852 *allocated_listen_port == 0) { 3853 *allocated_listen_port = get_local_port(sock); 3854 debug("Allocated listen port %d", 3855 *allocated_listen_port); 3856 } 3857 3858 /* Allocate a channel number for the socket. */ 3859 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3860 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3861 0, "port listener", 1); 3862 c->path = xstrdup(host); 3863 c->host_port = fwd->connect_port; 3864 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3865 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3866 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3867 c->listening_port = *allocated_listen_port; 3868 else 3869 c->listening_port = fwd->listen_port; 3870 success = 1; 3871 } 3872 if (success == 0) 3873 error_f("cannot listen to port: %d", fwd->listen_port); 3874 freeaddrinfo(aitop); 3875 return success; 3876 } 3877 3878 static int 3879 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3880 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3881 { 3882 struct sockaddr_un sunaddr; 3883 const char *path; 3884 Channel *c; 3885 int port, sock; 3886 mode_t omask; 3887 3888 switch (type) { 3889 case SSH_CHANNEL_UNIX_LISTENER: 3890 if (fwd->connect_path != NULL) { 3891 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3892 error("Local connecting path too long: %s", 3893 fwd->connect_path); 3894 return 0; 3895 } 3896 path = fwd->connect_path; 3897 port = PORT_STREAMLOCAL; 3898 } else { 3899 if (fwd->connect_host == NULL) { 3900 error("No forward host name."); 3901 return 0; 3902 } 3903 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3904 error("Forward host name too long."); 3905 return 0; 3906 } 3907 path = fwd->connect_host; 3908 port = fwd->connect_port; 3909 } 3910 break; 3911 case SSH_CHANNEL_RUNIX_LISTENER: 3912 path = fwd->listen_path; 3913 port = PORT_STREAMLOCAL; 3914 break; 3915 default: 3916 error_f("unexpected channel type %d", type); 3917 return 0; 3918 } 3919 3920 if (fwd->listen_path == NULL) { 3921 error("No forward path name."); 3922 return 0; 3923 } 3924 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3925 error("Local listening path too long: %s", fwd->listen_path); 3926 return 0; 3927 } 3928 3929 debug3_f("type %d path %s", type, fwd->listen_path); 3930 3931 /* Start a Unix domain listener. */ 3932 omask = umask(fwd_opts->streamlocal_bind_mask); 3933 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3934 fwd_opts->streamlocal_bind_unlink); 3935 umask(omask); 3936 if (sock < 0) 3937 return 0; 3938 3939 debug("Local forwarding listening on path %s.", fwd->listen_path); 3940 3941 /* Allocate a channel number for the socket. */ 3942 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 3943 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3944 0, "unix listener", 1); 3945 c->path = xstrdup(path); 3946 c->host_port = port; 3947 c->listening_port = PORT_STREAMLOCAL; 3948 c->listening_addr = xstrdup(fwd->listen_path); 3949 return 1; 3950 } 3951 3952 static int 3953 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3954 const char *host, u_short port) 3955 { 3956 u_int i; 3957 int found = 0; 3958 3959 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3960 Channel *c = ssh->chanctxt->channels[i]; 3961 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3962 continue; 3963 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3964 debug2_f("close channel %d", i); 3965 channel_free(ssh, c); 3966 found = 1; 3967 } 3968 } 3969 3970 return found; 3971 } 3972 3973 static int 3974 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3975 { 3976 u_int i; 3977 int found = 0; 3978 3979 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3980 Channel *c = ssh->chanctxt->channels[i]; 3981 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3982 continue; 3983 if (c->path == NULL) 3984 continue; 3985 if (strcmp(c->path, path) == 0) { 3986 debug2_f("close channel %d", i); 3987 channel_free(ssh, c); 3988 found = 1; 3989 } 3990 } 3991 3992 return found; 3993 } 3994 3995 int 3996 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3997 { 3998 if (fwd->listen_path != NULL) { 3999 return channel_cancel_rport_listener_streamlocal(ssh, 4000 fwd->listen_path); 4001 } else { 4002 return channel_cancel_rport_listener_tcpip(ssh, 4003 fwd->listen_host, fwd->listen_port); 4004 } 4005 } 4006 4007 static int 4008 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4009 const char *lhost, u_short lport, int cport, 4010 struct ForwardOptions *fwd_opts) 4011 { 4012 u_int i; 4013 int found = 0; 4014 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4015 4016 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4017 Channel *c = ssh->chanctxt->channels[i]; 4018 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4019 continue; 4020 if (c->listening_port != lport) 4021 continue; 4022 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4023 /* skip dynamic forwardings */ 4024 if (c->host_port == 0) 4025 continue; 4026 } else { 4027 if (c->host_port != cport) 4028 continue; 4029 } 4030 if ((c->listening_addr == NULL && addr != NULL) || 4031 (c->listening_addr != NULL && addr == NULL)) 4032 continue; 4033 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4034 debug2_f("close channel %d", i); 4035 channel_free(ssh, c); 4036 found = 1; 4037 } 4038 } 4039 4040 return found; 4041 } 4042 4043 static int 4044 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4045 { 4046 u_int i; 4047 int found = 0; 4048 4049 if (path == NULL) { 4050 error_f("no path specified."); 4051 return 0; 4052 } 4053 4054 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4055 Channel *c = ssh->chanctxt->channels[i]; 4056 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4057 continue; 4058 if (c->listening_addr == NULL) 4059 continue; 4060 if (strcmp(c->listening_addr, path) == 0) { 4061 debug2_f("close channel %d", i); 4062 channel_free(ssh, c); 4063 found = 1; 4064 } 4065 } 4066 4067 return found; 4068 } 4069 4070 int 4071 channel_cancel_lport_listener(struct ssh *ssh, 4072 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4073 { 4074 if (fwd->listen_path != NULL) { 4075 return channel_cancel_lport_listener_streamlocal(ssh, 4076 fwd->listen_path); 4077 } else { 4078 return channel_cancel_lport_listener_tcpip(ssh, 4079 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4080 } 4081 } 4082 4083 /* protocol local port fwd, used by ssh */ 4084 int 4085 channel_setup_local_fwd_listener(struct ssh *ssh, 4086 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4087 { 4088 if (fwd->listen_path != NULL) { 4089 return channel_setup_fwd_listener_streamlocal(ssh, 4090 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4091 } else { 4092 return channel_setup_fwd_listener_tcpip(ssh, 4093 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4094 } 4095 } 4096 4097 /* Matches a remote forwarding permission against a requested forwarding */ 4098 static int 4099 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4100 { 4101 int ret; 4102 char *lhost; 4103 4104 /* XXX add ACLs for streamlocal */ 4105 if (fwd->listen_path != NULL) 4106 return 1; 4107 4108 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4109 return 0; 4110 4111 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4112 allowed_open->listen_port != fwd->listen_port) 4113 return 0; 4114 4115 /* Match hostnames case-insensitively */ 4116 lhost = xstrdup(fwd->listen_host); 4117 lowercase(lhost); 4118 ret = match_pattern(lhost, allowed_open->listen_host); 4119 free(lhost); 4120 4121 return ret; 4122 } 4123 4124 /* Checks whether a requested remote forwarding is permitted */ 4125 static int 4126 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4127 { 4128 struct ssh_channels *sc = ssh->chanctxt; 4129 struct permission_set *pset = &sc->remote_perms; 4130 u_int i, permit, permit_adm = 1; 4131 struct permission *perm; 4132 4133 /* XXX apply GatewayPorts override before checking? */ 4134 4135 permit = pset->all_permitted; 4136 if (!permit) { 4137 for (i = 0; i < pset->num_permitted_user; i++) { 4138 perm = &pset->permitted_user[i]; 4139 if (remote_open_match(perm, fwd)) { 4140 permit = 1; 4141 break; 4142 } 4143 } 4144 } 4145 4146 if (pset->num_permitted_admin > 0) { 4147 permit_adm = 0; 4148 for (i = 0; i < pset->num_permitted_admin; i++) { 4149 perm = &pset->permitted_admin[i]; 4150 if (remote_open_match(perm, fwd)) { 4151 permit_adm = 1; 4152 break; 4153 } 4154 } 4155 } 4156 4157 return permit && permit_adm; 4158 } 4159 4160 /* protocol v2 remote port fwd, used by sshd */ 4161 int 4162 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4163 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4164 { 4165 if (!check_rfwd_permission(ssh, fwd)) { 4166 ssh_packet_send_debug(ssh, "port forwarding refused"); 4167 if (fwd->listen_path != NULL) 4168 /* XXX always allowed, see remote_open_match() */ 4169 logit("Received request from %.100s port %d to " 4170 "remote forward to path \"%.100s\", " 4171 "but the request was denied.", 4172 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4173 fwd->listen_path); 4174 else if(fwd->listen_host != NULL) 4175 logit("Received request from %.100s port %d to " 4176 "remote forward to host %.100s port %d, " 4177 "but the request was denied.", 4178 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4179 fwd->listen_host, fwd->listen_port ); 4180 else 4181 logit("Received request from %.100s port %d to remote " 4182 "forward, but the request was denied.", 4183 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4184 return 0; 4185 } 4186 if (fwd->listen_path != NULL) { 4187 return channel_setup_fwd_listener_streamlocal(ssh, 4188 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4189 } else { 4190 return channel_setup_fwd_listener_tcpip(ssh, 4191 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4192 fwd_opts); 4193 } 4194 } 4195 4196 /* 4197 * Translate the requested rfwd listen host to something usable for 4198 * this server. 4199 */ 4200 static const char * 4201 channel_rfwd_bind_host(const char *listen_host) 4202 { 4203 if (listen_host == NULL) { 4204 return "localhost"; 4205 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4206 return ""; 4207 } else 4208 return listen_host; 4209 } 4210 4211 /* 4212 * Initiate forwarding of connections to port "port" on remote host through 4213 * the secure channel to host:port from local side. 4214 * Returns handle (index) for updating the dynamic listen port with 4215 * channel_update_permission(). 4216 */ 4217 int 4218 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4219 { 4220 int r, success = 0, idx = -1; 4221 const char *host_to_connect, *listen_host, *listen_path; 4222 int port_to_connect, listen_port; 4223 4224 /* Send the forward request to the remote side. */ 4225 if (fwd->listen_path != NULL) { 4226 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4227 (r = sshpkt_put_cstring(ssh, 4228 "streamlocal-forward@openssh.com")) != 0 || 4229 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4230 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4231 (r = sshpkt_send(ssh)) != 0 || 4232 (r = ssh_packet_write_wait(ssh)) != 0) 4233 fatal_fr(r, "request streamlocal"); 4234 } else { 4235 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4236 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4237 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4238 (r = sshpkt_put_cstring(ssh, 4239 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4240 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4241 (r = sshpkt_send(ssh)) != 0 || 4242 (r = ssh_packet_write_wait(ssh)) != 0) 4243 fatal_fr(r, "request tcpip-forward"); 4244 } 4245 /* Assume that server accepts the request */ 4246 success = 1; 4247 if (success) { 4248 /* Record that connection to this host/port is permitted. */ 4249 host_to_connect = listen_host = listen_path = NULL; 4250 port_to_connect = listen_port = 0; 4251 if (fwd->connect_path != NULL) { 4252 host_to_connect = fwd->connect_path; 4253 port_to_connect = PORT_STREAMLOCAL; 4254 } else { 4255 host_to_connect = fwd->connect_host; 4256 port_to_connect = fwd->connect_port; 4257 } 4258 if (fwd->listen_path != NULL) { 4259 listen_path = fwd->listen_path; 4260 listen_port = PORT_STREAMLOCAL; 4261 } else { 4262 listen_host = fwd->listen_host; 4263 listen_port = fwd->listen_port; 4264 } 4265 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4266 host_to_connect, port_to_connect, 4267 listen_host, listen_path, listen_port, NULL); 4268 } 4269 return idx; 4270 } 4271 4272 static int 4273 open_match(struct permission *allowed_open, const char *requestedhost, 4274 int requestedport) 4275 { 4276 if (allowed_open->host_to_connect == NULL) 4277 return 0; 4278 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4279 allowed_open->port_to_connect != requestedport) 4280 return 0; 4281 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4282 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4283 return 0; 4284 return 1; 4285 } 4286 4287 /* 4288 * Note that in the listen host/port case 4289 * we don't support FWD_PERMIT_ANY_PORT and 4290 * need to translate between the configured-host (listen_host) 4291 * and what we've sent to the remote server (channel_rfwd_bind_host) 4292 */ 4293 static int 4294 open_listen_match_tcpip(struct permission *allowed_open, 4295 const char *requestedhost, u_short requestedport, int translate) 4296 { 4297 const char *allowed_host; 4298 4299 if (allowed_open->host_to_connect == NULL) 4300 return 0; 4301 if (allowed_open->listen_port != requestedport) 4302 return 0; 4303 if (!translate && allowed_open->listen_host == NULL && 4304 requestedhost == NULL) 4305 return 1; 4306 allowed_host = translate ? 4307 channel_rfwd_bind_host(allowed_open->listen_host) : 4308 allowed_open->listen_host; 4309 if (allowed_host == NULL || requestedhost == NULL || 4310 strcmp(allowed_host, requestedhost) != 0) 4311 return 0; 4312 return 1; 4313 } 4314 4315 static int 4316 open_listen_match_streamlocal(struct permission *allowed_open, 4317 const char *requestedpath) 4318 { 4319 if (allowed_open->host_to_connect == NULL) 4320 return 0; 4321 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4322 return 0; 4323 if (allowed_open->listen_path == NULL || 4324 strcmp(allowed_open->listen_path, requestedpath) != 0) 4325 return 0; 4326 return 1; 4327 } 4328 4329 /* 4330 * Request cancellation of remote forwarding of connection host:port from 4331 * local side. 4332 */ 4333 static int 4334 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4335 const char *host, u_short port) 4336 { 4337 struct ssh_channels *sc = ssh->chanctxt; 4338 struct permission_set *pset = &sc->local_perms; 4339 int r; 4340 u_int i; 4341 struct permission *perm = NULL; 4342 4343 for (i = 0; i < pset->num_permitted_user; i++) { 4344 perm = &pset->permitted_user[i]; 4345 if (open_listen_match_tcpip(perm, host, port, 0)) 4346 break; 4347 perm = NULL; 4348 } 4349 if (perm == NULL) { 4350 debug_f("requested forward not found"); 4351 return -1; 4352 } 4353 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4354 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4355 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4356 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4357 (r = sshpkt_put_u32(ssh, port)) != 0 || 4358 (r = sshpkt_send(ssh)) != 0) 4359 fatal_fr(r, "send cancel"); 4360 4361 fwd_perm_clear(perm); /* unregister */ 4362 4363 return 0; 4364 } 4365 4366 /* 4367 * Request cancellation of remote forwarding of Unix domain socket 4368 * path from local side. 4369 */ 4370 static int 4371 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4372 { 4373 struct ssh_channels *sc = ssh->chanctxt; 4374 struct permission_set *pset = &sc->local_perms; 4375 int r; 4376 u_int i; 4377 struct permission *perm = NULL; 4378 4379 for (i = 0; i < pset->num_permitted_user; i++) { 4380 perm = &pset->permitted_user[i]; 4381 if (open_listen_match_streamlocal(perm, path)) 4382 break; 4383 perm = NULL; 4384 } 4385 if (perm == NULL) { 4386 debug_f("requested forward not found"); 4387 return -1; 4388 } 4389 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4390 (r = sshpkt_put_cstring(ssh, 4391 "cancel-streamlocal-forward@openssh.com")) != 0 || 4392 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4393 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4394 (r = sshpkt_send(ssh)) != 0) 4395 fatal_fr(r, "send cancel"); 4396 4397 fwd_perm_clear(perm); /* unregister */ 4398 4399 return 0; 4400 } 4401 4402 /* 4403 * Request cancellation of remote forwarding of a connection from local side. 4404 */ 4405 int 4406 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4407 { 4408 if (fwd->listen_path != NULL) { 4409 return channel_request_rforward_cancel_streamlocal(ssh, 4410 fwd->listen_path); 4411 } else { 4412 return channel_request_rforward_cancel_tcpip(ssh, 4413 fwd->listen_host, 4414 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4415 } 4416 } 4417 4418 /* 4419 * Permits opening to any host/port if permitted_user[] is empty. This is 4420 * usually called by the server, because the user could connect to any port 4421 * anyway, and the server has no way to know but to trust the client anyway. 4422 */ 4423 void 4424 channel_permit_all(struct ssh *ssh, int where) 4425 { 4426 struct permission_set *pset = permission_set_get(ssh, where); 4427 4428 if (pset->num_permitted_user == 0) 4429 pset->all_permitted = 1; 4430 } 4431 4432 /* 4433 * Permit the specified host/port for forwarding. 4434 */ 4435 void 4436 channel_add_permission(struct ssh *ssh, int who, int where, 4437 char *host, int port) 4438 { 4439 int local = where == FORWARD_LOCAL; 4440 struct permission_set *pset = permission_set_get(ssh, where); 4441 4442 debug("allow %s forwarding to host %s port %d", 4443 fwd_ident(who, where), host, port); 4444 /* 4445 * Remote forwards set listen_host/port, local forwards set 4446 * host/port_to_connect. 4447 */ 4448 permission_set_add(ssh, who, where, 4449 local ? host : 0, local ? port : 0, 4450 local ? NULL : host, NULL, local ? 0 : port, NULL); 4451 pset->all_permitted = 0; 4452 } 4453 4454 /* 4455 * Administratively disable forwarding. 4456 */ 4457 void 4458 channel_disable_admin(struct ssh *ssh, int where) 4459 { 4460 channel_clear_permission(ssh, FORWARD_ADM, where); 4461 permission_set_add(ssh, FORWARD_ADM, where, 4462 NULL, 0, NULL, NULL, 0, NULL); 4463 } 4464 4465 /* 4466 * Clear a list of permitted opens. 4467 */ 4468 void 4469 channel_clear_permission(struct ssh *ssh, int who, int where) 4470 { 4471 struct permission **permp; 4472 u_int *npermp; 4473 4474 permission_set_get_array(ssh, who, where, &permp, &npermp); 4475 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4476 *npermp = 0; 4477 } 4478 4479 /* 4480 * Update the listen port for a dynamic remote forward, after 4481 * the actual 'newport' has been allocated. If 'newport' < 0 is 4482 * passed then they entry will be invalidated. 4483 */ 4484 void 4485 channel_update_permission(struct ssh *ssh, int idx, int newport) 4486 { 4487 struct permission_set *pset = &ssh->chanctxt->local_perms; 4488 4489 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4490 debug_f("index out of range: %d num_permitted_user %d", 4491 idx, pset->num_permitted_user); 4492 return; 4493 } 4494 debug("%s allowed port %d for forwarding to host %s port %d", 4495 newport > 0 ? "Updating" : "Removing", 4496 newport, 4497 pset->permitted_user[idx].host_to_connect, 4498 pset->permitted_user[idx].port_to_connect); 4499 if (newport <= 0) 4500 fwd_perm_clear(&pset->permitted_user[idx]); 4501 else { 4502 pset->permitted_user[idx].listen_port = 4503 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4504 } 4505 } 4506 4507 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4508 int 4509 permitopen_port(const char *p) 4510 { 4511 int port; 4512 4513 if (strcmp(p, "*") == 0) 4514 return FWD_PERMIT_ANY_PORT; 4515 if ((port = a2port(p)) > 0) 4516 return port; 4517 return -1; 4518 } 4519 4520 /* Try to start non-blocking connect to next host in cctx list */ 4521 static int 4522 connect_next(struct channel_connect *cctx) 4523 { 4524 int sock, saved_errno; 4525 struct sockaddr_un *sunaddr; 4526 char ntop[NI_MAXHOST]; 4527 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4528 4529 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4530 switch (cctx->ai->ai_family) { 4531 case AF_UNIX: 4532 /* unix:pathname instead of host:port */ 4533 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4534 strlcpy(ntop, "unix", sizeof(ntop)); 4535 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4536 break; 4537 case AF_INET: 4538 case AF_INET6: 4539 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4540 ntop, sizeof(ntop), strport, sizeof(strport), 4541 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4542 error_f("getnameinfo failed"); 4543 continue; 4544 } 4545 break; 4546 default: 4547 continue; 4548 } 4549 debug_f("start for host %.100s ([%.100s]:%s)", 4550 cctx->host, ntop, strport); 4551 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4552 cctx->ai->ai_protocol)) == -1) { 4553 if (cctx->ai->ai_next == NULL) 4554 error("socket: %.100s", strerror(errno)); 4555 else 4556 verbose("socket: %.100s", strerror(errno)); 4557 continue; 4558 } 4559 if (set_nonblock(sock) == -1) 4560 fatal_f("set_nonblock(%d)", sock); 4561 if (connect(sock, cctx->ai->ai_addr, 4562 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4563 debug_f("host %.100s ([%.100s]:%s): %.100s", 4564 cctx->host, ntop, strport, strerror(errno)); 4565 saved_errno = errno; 4566 close(sock); 4567 errno = saved_errno; 4568 continue; /* fail -- try next */ 4569 } 4570 if (cctx->ai->ai_family != AF_UNIX) 4571 set_nodelay(sock); 4572 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4573 cctx->host, ntop, strport, sock); 4574 cctx->ai = cctx->ai->ai_next; 4575 return sock; 4576 } 4577 return -1; 4578 } 4579 4580 static void 4581 channel_connect_ctx_free(struct channel_connect *cctx) 4582 { 4583 free(cctx->host); 4584 if (cctx->aitop) { 4585 if (cctx->aitop->ai_family == AF_UNIX) 4586 free(cctx->aitop); 4587 else 4588 freeaddrinfo(cctx->aitop); 4589 } 4590 memset(cctx, 0, sizeof(*cctx)); 4591 } 4592 4593 /* 4594 * Return connecting socket to remote host:port or local socket path, 4595 * passing back the failure reason if appropriate. 4596 */ 4597 static int 4598 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4599 char *ctype, char *rname, struct channel_connect *cctx, 4600 int *reason, const char **errmsg) 4601 { 4602 struct addrinfo hints; 4603 int gaierr; 4604 int sock = -1; 4605 char strport[NI_MAXSERV]; 4606 4607 if (port == PORT_STREAMLOCAL) { 4608 struct sockaddr_un *sunaddr; 4609 struct addrinfo *ai; 4610 4611 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4612 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4613 return -1; 4614 } 4615 4616 /* 4617 * Fake up a struct addrinfo for AF_UNIX connections. 4618 * channel_connect_ctx_free() must check ai_family 4619 * and use free() not freeaddirinfo() for AF_UNIX. 4620 */ 4621 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4622 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4623 ai->ai_addr = (struct sockaddr *)(ai + 1); 4624 ai->ai_addrlen = sizeof(*sunaddr); 4625 ai->ai_family = AF_UNIX; 4626 ai->ai_socktype = socktype; 4627 ai->ai_protocol = PF_UNSPEC; 4628 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4629 sunaddr->sun_family = AF_UNIX; 4630 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4631 cctx->aitop = ai; 4632 } else { 4633 memset(&hints, 0, sizeof(hints)); 4634 hints.ai_family = ssh->chanctxt->IPv4or6; 4635 hints.ai_socktype = socktype; 4636 snprintf(strport, sizeof strport, "%d", port); 4637 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4638 != 0) { 4639 if (errmsg != NULL) 4640 *errmsg = ssh_gai_strerror(gaierr); 4641 if (reason != NULL) 4642 *reason = SSH2_OPEN_CONNECT_FAILED; 4643 error("connect_to %.100s: unknown host (%s)", name, 4644 ssh_gai_strerror(gaierr)); 4645 return -1; 4646 } 4647 } 4648 4649 cctx->host = xstrdup(name); 4650 cctx->port = port; 4651 cctx->ai = cctx->aitop; 4652 4653 if ((sock = connect_next(cctx)) == -1) { 4654 error("connect to %.100s port %d failed: %s", 4655 name, port, strerror(errno)); 4656 return -1; 4657 } 4658 4659 return sock; 4660 } 4661 4662 /* Return CONNECTING channel to remote host:port or local socket path */ 4663 static Channel * 4664 connect_to(struct ssh *ssh, const char *host, int port, 4665 char *ctype, char *rname) 4666 { 4667 struct channel_connect cctx; 4668 Channel *c; 4669 int sock; 4670 4671 memset(&cctx, 0, sizeof(cctx)); 4672 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4673 &cctx, NULL, NULL); 4674 if (sock == -1) { 4675 channel_connect_ctx_free(&cctx); 4676 return NULL; 4677 } 4678 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4679 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4680 c->host_port = port; 4681 c->path = xstrdup(host); 4682 c->connect_ctx = cctx; 4683 4684 return c; 4685 } 4686 4687 /* 4688 * returns either the newly connected channel or the downstream channel 4689 * that needs to deal with this connection. 4690 */ 4691 Channel * 4692 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4693 u_short listen_port, char *ctype, char *rname) 4694 { 4695 struct ssh_channels *sc = ssh->chanctxt; 4696 struct permission_set *pset = &sc->local_perms; 4697 u_int i; 4698 struct permission *perm; 4699 4700 for (i = 0; i < pset->num_permitted_user; i++) { 4701 perm = &pset->permitted_user[i]; 4702 if (open_listen_match_tcpip(perm, 4703 listen_host, listen_port, 1)) { 4704 if (perm->downstream) 4705 return perm->downstream; 4706 if (perm->port_to_connect == 0) 4707 return rdynamic_connect_prepare(ssh, 4708 ctype, rname); 4709 return connect_to(ssh, 4710 perm->host_to_connect, perm->port_to_connect, 4711 ctype, rname); 4712 } 4713 } 4714 error("WARNING: Server requests forwarding for unknown listen_port %d", 4715 listen_port); 4716 return NULL; 4717 } 4718 4719 Channel * 4720 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4721 char *ctype, char *rname) 4722 { 4723 struct ssh_channels *sc = ssh->chanctxt; 4724 struct permission_set *pset = &sc->local_perms; 4725 u_int i; 4726 struct permission *perm; 4727 4728 for (i = 0; i < pset->num_permitted_user; i++) { 4729 perm = &pset->permitted_user[i]; 4730 if (open_listen_match_streamlocal(perm, path)) { 4731 return connect_to(ssh, 4732 perm->host_to_connect, perm->port_to_connect, 4733 ctype, rname); 4734 } 4735 } 4736 error("WARNING: Server requests forwarding for unknown path %.100s", 4737 path); 4738 return NULL; 4739 } 4740 4741 /* Check if connecting to that port is permitted and connect. */ 4742 Channel * 4743 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4744 char *ctype, char *rname, int *reason, const char **errmsg) 4745 { 4746 struct ssh_channels *sc = ssh->chanctxt; 4747 struct permission_set *pset = &sc->local_perms; 4748 struct channel_connect cctx; 4749 Channel *c; 4750 u_int i, permit, permit_adm = 1; 4751 int sock; 4752 struct permission *perm; 4753 4754 permit = pset->all_permitted; 4755 if (!permit) { 4756 for (i = 0; i < pset->num_permitted_user; i++) { 4757 perm = &pset->permitted_user[i]; 4758 if (open_match(perm, host, port)) { 4759 permit = 1; 4760 break; 4761 } 4762 } 4763 } 4764 4765 if (pset->num_permitted_admin > 0) { 4766 permit_adm = 0; 4767 for (i = 0; i < pset->num_permitted_admin; i++) { 4768 perm = &pset->permitted_admin[i]; 4769 if (open_match(perm, host, port)) { 4770 permit_adm = 1; 4771 break; 4772 } 4773 } 4774 } 4775 4776 if (!permit || !permit_adm) { 4777 logit("Received request from %.100s port %d to connect to " 4778 "host %.100s port %d, but the request was denied.", 4779 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4780 if (reason != NULL) 4781 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4782 return NULL; 4783 } 4784 4785 memset(&cctx, 0, sizeof(cctx)); 4786 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4787 &cctx, reason, errmsg); 4788 if (sock == -1) { 4789 channel_connect_ctx_free(&cctx); 4790 return NULL; 4791 } 4792 4793 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4794 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4795 c->host_port = port; 4796 c->path = xstrdup(host); 4797 c->connect_ctx = cctx; 4798 4799 return c; 4800 } 4801 4802 /* Check if connecting to that path is permitted and connect. */ 4803 Channel * 4804 channel_connect_to_path(struct ssh *ssh, const char *path, 4805 char *ctype, char *rname) 4806 { 4807 struct ssh_channels *sc = ssh->chanctxt; 4808 struct permission_set *pset = &sc->local_perms; 4809 u_int i, permit, permit_adm = 1; 4810 struct permission *perm; 4811 4812 permit = pset->all_permitted; 4813 if (!permit) { 4814 for (i = 0; i < pset->num_permitted_user; i++) { 4815 perm = &pset->permitted_user[i]; 4816 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4817 permit = 1; 4818 break; 4819 } 4820 } 4821 } 4822 4823 if (pset->num_permitted_admin > 0) { 4824 permit_adm = 0; 4825 for (i = 0; i < pset->num_permitted_admin; i++) { 4826 perm = &pset->permitted_admin[i]; 4827 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4828 permit_adm = 1; 4829 break; 4830 } 4831 } 4832 } 4833 4834 if (!permit || !permit_adm) { 4835 logit("Received request to connect to path %.100s, " 4836 "but the request was denied.", path); 4837 return NULL; 4838 } 4839 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4840 } 4841 4842 void 4843 channel_send_window_changes(struct ssh *ssh) 4844 { 4845 struct ssh_channels *sc = ssh->chanctxt; 4846 struct winsize ws; 4847 int r; 4848 u_int i; 4849 4850 for (i = 0; i < sc->channels_alloc; i++) { 4851 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4852 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4853 continue; 4854 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4855 continue; 4856 channel_request_start(ssh, i, "window-change", 0); 4857 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4858 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4859 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4860 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4861 (r = sshpkt_send(ssh)) != 0) 4862 fatal_fr(r, "channel %u; send window-change", i); 4863 } 4864 } 4865 4866 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4867 static Channel * 4868 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4869 { 4870 Channel *c; 4871 int r; 4872 4873 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4874 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4875 c->host_port = 0; 4876 c->path = NULL; 4877 4878 /* 4879 * We need to open the channel before we have a FD, 4880 * so that we can get SOCKS header from peer. 4881 */ 4882 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4883 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4884 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4885 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4886 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4887 fatal_fr(r, "channel %i; confirm", c->self); 4888 return c; 4889 } 4890 4891 /* Return CONNECTING socket to remote host:port or local socket path */ 4892 static int 4893 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4894 { 4895 struct ssh_channels *sc = ssh->chanctxt; 4896 struct permission_set *pset = &sc->local_perms; 4897 struct permission *perm; 4898 struct channel_connect cctx; 4899 u_int i, permit_adm = 1; 4900 int sock; 4901 4902 if (pset->num_permitted_admin > 0) { 4903 permit_adm = 0; 4904 for (i = 0; i < pset->num_permitted_admin; i++) { 4905 perm = &pset->permitted_admin[i]; 4906 if (open_match(perm, c->path, c->host_port)) { 4907 permit_adm = 1; 4908 break; 4909 } 4910 } 4911 } 4912 if (!permit_adm) { 4913 debug_f("requested forward not permitted"); 4914 return -1; 4915 } 4916 4917 memset(&cctx, 0, sizeof(cctx)); 4918 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4919 NULL, &cctx, NULL, NULL); 4920 if (sock == -1) 4921 channel_connect_ctx_free(&cctx); 4922 else { 4923 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4924 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4925 c->connect_ctx = cctx; 4926 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4927 } 4928 return sock; 4929 } 4930 4931 /* -- X11 forwarding */ 4932 4933 /* 4934 * Creates an internet domain socket for listening for X11 connections. 4935 * Returns 0 and a suitable display number for the DISPLAY variable 4936 * stored in display_numberp , or -1 if an error occurs. 4937 */ 4938 int 4939 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4940 int x11_use_localhost, int single_connection, 4941 u_int *display_numberp, int **chanids) 4942 { 4943 Channel *nc = NULL; 4944 int display_number, sock; 4945 u_short port; 4946 struct addrinfo hints, *ai, *aitop; 4947 char strport[NI_MAXSERV]; 4948 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4949 4950 if (chanids == NULL) 4951 return -1; 4952 4953 for (display_number = x11_display_offset; 4954 display_number < MAX_DISPLAYS; 4955 display_number++) { 4956 port = 6000 + display_number; 4957 memset(&hints, 0, sizeof(hints)); 4958 hints.ai_family = ssh->chanctxt->IPv4or6; 4959 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4960 hints.ai_socktype = SOCK_STREAM; 4961 snprintf(strport, sizeof strport, "%d", port); 4962 if ((gaierr = getaddrinfo(NULL, strport, 4963 &hints, &aitop)) != 0) { 4964 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4965 return -1; 4966 } 4967 for (ai = aitop; ai; ai = ai->ai_next) { 4968 if (ai->ai_family != AF_INET && 4969 ai->ai_family != AF_INET6) 4970 continue; 4971 sock = socket(ai->ai_family, ai->ai_socktype, 4972 ai->ai_protocol); 4973 if (sock == -1) { 4974 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 4975 #ifdef EPFNOSUPPORT 4976 && (errno != EPFNOSUPPORT) 4977 #endif 4978 ) { 4979 error("socket: %.100s", strerror(errno)); 4980 freeaddrinfo(aitop); 4981 return -1; 4982 } else { 4983 debug("x11_create_display_inet: Socket family %d not supported", 4984 ai->ai_family); 4985 continue; 4986 } 4987 } 4988 if (ai->ai_family == AF_INET6) 4989 sock_set_v6only(sock); 4990 if (x11_use_localhost) 4991 set_reuseaddr(sock); 4992 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4993 debug2_f("bind port %d: %.100s", port, 4994 strerror(errno)); 4995 close(sock); 4996 for (n = 0; n < num_socks; n++) 4997 close(socks[n]); 4998 num_socks = 0; 4999 break; 5000 } 5001 socks[num_socks++] = sock; 5002 if (num_socks == NUM_SOCKS) 5003 break; 5004 } 5005 freeaddrinfo(aitop); 5006 if (num_socks > 0) 5007 break; 5008 } 5009 if (display_number >= MAX_DISPLAYS) { 5010 error("Failed to allocate internet-domain X11 display socket."); 5011 return -1; 5012 } 5013 /* Start listening for connections on the socket. */ 5014 for (n = 0; n < num_socks; n++) { 5015 sock = socks[n]; 5016 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5017 error("listen: %.100s", strerror(errno)); 5018 close(sock); 5019 return -1; 5020 } 5021 } 5022 5023 /* Allocate a channel for each socket. */ 5024 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5025 for (n = 0; n < num_socks; n++) { 5026 sock = socks[n]; 5027 nc = channel_new(ssh, "x11-listener", 5028 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5029 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5030 0, "X11 inet listener", 1); 5031 nc->single_connection = single_connection; 5032 (*chanids)[n] = nc->self; 5033 } 5034 (*chanids)[n] = -1; 5035 5036 /* Return the display number for the DISPLAY environment variable. */ 5037 *display_numberp = display_number; 5038 return 0; 5039 } 5040 5041 static int 5042 connect_local_xsocket_path(const char *pathname) 5043 { 5044 int sock; 5045 struct sockaddr_un addr; 5046 5047 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5048 if (sock == -1) 5049 error("socket: %.100s", strerror(errno)); 5050 memset(&addr, 0, sizeof(addr)); 5051 addr.sun_family = AF_UNIX; 5052 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 5053 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5054 return sock; 5055 close(sock); 5056 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5057 return -1; 5058 } 5059 5060 static int 5061 connect_local_xsocket(u_int dnr) 5062 { 5063 char buf[1024]; 5064 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 5065 return connect_local_xsocket_path(buf); 5066 } 5067 5068 #ifdef __APPLE__ 5069 static int 5070 is_path_to_xsocket(const char *display, char *path, size_t pathlen) 5071 { 5072 struct stat sbuf; 5073 5074 if (strlcpy(path, display, pathlen) >= pathlen) { 5075 error("%s: display path too long", __func__); 5076 return 0; 5077 } 5078 if (display[0] != '/') 5079 return 0; 5080 if (stat(path, &sbuf) == 0) { 5081 return 1; 5082 } else { 5083 char *dot = strrchr(path, '.'); 5084 if (dot != NULL) { 5085 *dot = '\0'; 5086 if (stat(path, &sbuf) == 0) { 5087 return 1; 5088 } 5089 } 5090 } 5091 return 0; 5092 } 5093 #endif 5094 5095 int 5096 x11_connect_display(struct ssh *ssh) 5097 { 5098 u_int display_number; 5099 const char *display; 5100 char buf[1024], *cp; 5101 struct addrinfo hints, *ai, *aitop; 5102 char strport[NI_MAXSERV]; 5103 int gaierr, sock = 0; 5104 5105 /* Try to open a socket for the local X server. */ 5106 display = getenv("DISPLAY"); 5107 if (!display) { 5108 error("DISPLAY not set."); 5109 return -1; 5110 } 5111 /* 5112 * Now we decode the value of the DISPLAY variable and make a 5113 * connection to the real X server. 5114 */ 5115 5116 #ifdef __APPLE__ 5117 /* Check if display is a path to a socket (as set by launchd). */ 5118 { 5119 char path[PATH_MAX]; 5120 5121 if (is_path_to_xsocket(display, path, sizeof(path))) { 5122 debug("x11_connect_display: $DISPLAY is launchd"); 5123 5124 /* Create a socket. */ 5125 sock = connect_local_xsocket_path(path); 5126 if (sock < 0) 5127 return -1; 5128 5129 /* OK, we now have a connection to the display. */ 5130 return sock; 5131 } 5132 } 5133 #endif 5134 /* 5135 * Check if it is a unix domain socket. Unix domain displays are in 5136 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5137 */ 5138 if (strncmp(display, "unix:", 5) == 0 || 5139 display[0] == ':') { 5140 /* Connect to the unix domain socket. */ 5141 if (sscanf(strrchr(display, ':') + 1, "%u", 5142 &display_number) != 1) { 5143 error("Could not parse display number from DISPLAY: " 5144 "%.100s", display); 5145 return -1; 5146 } 5147 /* Create a socket. */ 5148 sock = connect_local_xsocket(display_number); 5149 if (sock < 0) 5150 return -1; 5151 5152 /* OK, we now have a connection to the display. */ 5153 return sock; 5154 } 5155 /* 5156 * Connect to an inet socket. The DISPLAY value is supposedly 5157 * hostname:d[.s], where hostname may also be numeric IP address. 5158 */ 5159 strlcpy(buf, display, sizeof(buf)); 5160 cp = strchr(buf, ':'); 5161 if (!cp) { 5162 error("Could not find ':' in DISPLAY: %.100s", display); 5163 return -1; 5164 } 5165 *cp = 0; 5166 /* 5167 * buf now contains the host name. But first we parse the 5168 * display number. 5169 */ 5170 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5171 error("Could not parse display number from DISPLAY: %.100s", 5172 display); 5173 return -1; 5174 } 5175 5176 /* Look up the host address */ 5177 memset(&hints, 0, sizeof(hints)); 5178 hints.ai_family = ssh->chanctxt->IPv4or6; 5179 hints.ai_socktype = SOCK_STREAM; 5180 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5181 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5182 error("%.100s: unknown host. (%s)", buf, 5183 ssh_gai_strerror(gaierr)); 5184 return -1; 5185 } 5186 for (ai = aitop; ai; ai = ai->ai_next) { 5187 /* Create a socket. */ 5188 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5189 if (sock == -1) { 5190 debug2("socket: %.100s", strerror(errno)); 5191 continue; 5192 } 5193 /* Connect it to the display. */ 5194 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5195 debug2("connect %.100s port %u: %.100s", buf, 5196 6000 + display_number, strerror(errno)); 5197 close(sock); 5198 continue; 5199 } 5200 /* Success */ 5201 break; 5202 } 5203 freeaddrinfo(aitop); 5204 if (!ai) { 5205 error("connect %.100s port %u: %.100s", buf, 5206 6000 + display_number, strerror(errno)); 5207 return -1; 5208 } 5209 set_nodelay(sock); 5210 return sock; 5211 } 5212 5213 /* 5214 * Requests forwarding of X11 connections, generates fake authentication 5215 * data, and enables authentication spoofing. 5216 * This should be called in the client only. 5217 */ 5218 void 5219 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5220 const char *disp, const char *proto, const char *data, int want_reply) 5221 { 5222 struct ssh_channels *sc = ssh->chanctxt; 5223 u_int data_len = (u_int) strlen(data) / 2; 5224 u_int i, value; 5225 const char *cp; 5226 char *new_data; 5227 int r, screen_number; 5228 5229 if (sc->x11_saved_display == NULL) 5230 sc->x11_saved_display = xstrdup(disp); 5231 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5232 error("x11_request_forwarding_with_spoofing: different " 5233 "$DISPLAY already forwarded"); 5234 return; 5235 } 5236 5237 cp = strchr(disp, ':'); 5238 if (cp) 5239 cp = strchr(cp, '.'); 5240 if (cp) 5241 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5242 else 5243 screen_number = 0; 5244 5245 if (sc->x11_saved_proto == NULL) { 5246 /* Save protocol name. */ 5247 sc->x11_saved_proto = xstrdup(proto); 5248 5249 /* Extract real authentication data. */ 5250 sc->x11_saved_data = xmalloc(data_len); 5251 for (i = 0; i < data_len; i++) { 5252 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5253 fatal("x11_request_forwarding: bad " 5254 "authentication data: %.100s", data); 5255 } 5256 sc->x11_saved_data[i] = value; 5257 } 5258 sc->x11_saved_data_len = data_len; 5259 5260 /* Generate fake data of the same length. */ 5261 sc->x11_fake_data = xmalloc(data_len); 5262 arc4random_buf(sc->x11_fake_data, data_len); 5263 sc->x11_fake_data_len = data_len; 5264 } 5265 5266 /* Convert the fake data into hex. */ 5267 new_data = tohex(sc->x11_fake_data, data_len); 5268 5269 /* Send the request packet. */ 5270 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5271 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5272 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5273 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5274 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5275 (r = sshpkt_send(ssh)) != 0 || 5276 (r = ssh_packet_write_wait(ssh)) != 0) 5277 fatal_fr(r, "send x11-req"); 5278 free(new_data); 5279 } 5280