1 /* $OpenBSD: channels.c,v 1.433 2023/09/04 00:01:46 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 #include <sys/ioctl.h> 45 #include <sys/un.h> 46 #include <sys/socket.h> 47 #include <sys/time.h> 48 #include <sys/queue.h> 49 50 #include <netinet/in.h> 51 #include <arpa/inet.h> 52 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <limits.h> 56 #include <netdb.h> 57 #include <poll.h> 58 #include <stdarg.h> 59 #include <stdint.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <termios.h> 64 #include <unistd.h> 65 66 #include "xmalloc.h" 67 #include "ssh.h" 68 #include "ssh2.h" 69 #include "ssherr.h" 70 #include "sshbuf.h" 71 #include "packet.h" 72 #include "log.h" 73 #include "misc.h" 74 #include "channels.h" 75 #include "compat.h" 76 #include "canohost.h" 77 #include "sshkey.h" 78 #include "authfd.h" 79 #include "pathnames.h" 80 #include "match.h" 81 82 /* XXX remove once we're satisfied there's no lurking bugs */ 83 /* #define DEBUG_CHANNEL_POLL 1 */ 84 85 /* -- agent forwarding */ 86 #define NUM_SOCKS 10 87 88 /* -- tcp forwarding */ 89 /* special-case port number meaning allow any port */ 90 #define FWD_PERMIT_ANY_PORT 0 91 92 /* special-case wildcard meaning allow any host */ 93 #define FWD_PERMIT_ANY_HOST "*" 94 95 /* -- X11 forwarding */ 96 /* Maximum number of fake X11 displays to try. */ 97 #define MAX_DISPLAYS 1000 98 99 /* Per-channel callback for pre/post IO actions */ 100 typedef void chan_fn(struct ssh *, Channel *c); 101 102 /* 103 * Data structure for storing which hosts are permitted for forward requests. 104 * The local sides of any remote forwards are stored in this array to prevent 105 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 106 * network (which might be behind a firewall). 107 */ 108 /* XXX: streamlocal wants a path instead of host:port */ 109 /* Overload host_to_connect; we could just make this match Forward */ 110 /* XXX - can we use listen_host instead of listen_path? */ 111 struct permission { 112 char *host_to_connect; /* Connect to 'host'. */ 113 int port_to_connect; /* Connect to 'port'. */ 114 char *listen_host; /* Remote side should listen address. */ 115 char *listen_path; /* Remote side should listen path. */ 116 int listen_port; /* Remote side should listen port. */ 117 Channel *downstream; /* Downstream mux*/ 118 }; 119 120 /* 121 * Stores the forwarding permission state for a single direction (local or 122 * remote). 123 */ 124 struct permission_set { 125 /* 126 * List of all local permitted host/port pairs to allow for the 127 * user. 128 */ 129 u_int num_permitted_user; 130 struct permission *permitted_user; 131 132 /* 133 * List of all permitted host/port pairs to allow for the admin. 134 */ 135 u_int num_permitted_admin; 136 struct permission *permitted_admin; 137 138 /* 139 * If this is true, all opens/listens are permitted. This is the 140 * case on the server on which we have to trust the client anyway, 141 * and the user could do anything after logging in. 142 */ 143 int all_permitted; 144 }; 145 146 /* Used to record timeouts per channel type */ 147 struct ssh_channel_timeout { 148 char *type_pattern; 149 int timeout_secs; 150 }; 151 152 /* Master structure for channels state */ 153 struct ssh_channels { 154 /* 155 * Pointer to an array containing all allocated channels. The array 156 * is dynamically extended as needed. 157 */ 158 Channel **channels; 159 160 /* 161 * Size of the channel array. All slots of the array must always be 162 * initialized (at least the type field); unused slots set to NULL 163 */ 164 u_int channels_alloc; 165 166 /* 167 * 'channel_pre*' are called just before IO to add any bits 168 * relevant to channels in the c->io_want bitmasks. 169 * 170 * 'channel_post*': perform any appropriate operations for 171 * channels which have c->io_ready events pending. 172 */ 173 chan_fn **channel_pre; 174 chan_fn **channel_post; 175 176 /* -- tcp forwarding */ 177 struct permission_set local_perms; 178 struct permission_set remote_perms; 179 180 /* -- X11 forwarding */ 181 182 /* Saved X11 local (client) display. */ 183 char *x11_saved_display; 184 185 /* Saved X11 authentication protocol name. */ 186 char *x11_saved_proto; 187 188 /* Saved X11 authentication data. This is the real data. */ 189 char *x11_saved_data; 190 u_int x11_saved_data_len; 191 192 /* Deadline after which all X11 connections are refused */ 193 time_t x11_refuse_time; 194 195 /* 196 * Fake X11 authentication data. This is what the server will be 197 * sending us; we should replace any occurrences of this by the 198 * real data. 199 */ 200 u_char *x11_fake_data; 201 u_int x11_fake_data_len; 202 203 /* AF_UNSPEC or AF_INET or AF_INET6 */ 204 int IPv4or6; 205 206 /* Channel timeouts by type */ 207 struct ssh_channel_timeout *timeouts; 208 size_t ntimeouts; 209 }; 210 211 /* helper */ 212 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 213 static const char *channel_rfwd_bind_host(const char *listen_host); 214 215 /* non-blocking connect helpers */ 216 static int connect_next(struct channel_connect *); 217 static void channel_connect_ctx_free(struct channel_connect *); 218 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 219 static int rdynamic_connect_finish(struct ssh *, Channel *); 220 221 /* Setup helper */ 222 static void channel_handler_init(struct ssh_channels *sc); 223 224 /* -- channel core */ 225 226 void 227 channel_init_channels(struct ssh *ssh) 228 { 229 struct ssh_channels *sc; 230 231 if ((sc = calloc(1, sizeof(*sc))) == NULL) 232 fatal_f("allocation failed"); 233 sc->channels_alloc = 10; 234 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 235 sc->IPv4or6 = AF_UNSPEC; 236 channel_handler_init(sc); 237 238 ssh->chanctxt = sc; 239 } 240 241 Channel * 242 channel_by_id(struct ssh *ssh, int id) 243 { 244 Channel *c; 245 246 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 247 logit_f("%d: bad id", id); 248 return NULL; 249 } 250 c = ssh->chanctxt->channels[id]; 251 if (c == NULL) { 252 logit_f("%d: bad id: channel free", id); 253 return NULL; 254 } 255 return c; 256 } 257 258 Channel * 259 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 260 { 261 Channel *c; 262 u_int i; 263 264 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 265 c = ssh->chanctxt->channels[i]; 266 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 267 return c; 268 } 269 return NULL; 270 } 271 272 /* 273 * Returns the channel if it is allowed to receive protocol messages. 274 * Private channels, like listening sockets, may not receive messages. 275 */ 276 Channel * 277 channel_lookup(struct ssh *ssh, int id) 278 { 279 Channel *c; 280 281 if ((c = channel_by_id(ssh, id)) == NULL) 282 return NULL; 283 284 switch (c->type) { 285 case SSH_CHANNEL_X11_OPEN: 286 case SSH_CHANNEL_LARVAL: 287 case SSH_CHANNEL_CONNECTING: 288 case SSH_CHANNEL_DYNAMIC: 289 case SSH_CHANNEL_RDYNAMIC_OPEN: 290 case SSH_CHANNEL_RDYNAMIC_FINISH: 291 case SSH_CHANNEL_OPENING: 292 case SSH_CHANNEL_OPEN: 293 case SSH_CHANNEL_ABANDONED: 294 case SSH_CHANNEL_MUX_PROXY: 295 return c; 296 } 297 logit("Non-public channel %d, type %d.", id, c->type); 298 return NULL; 299 } 300 301 /* 302 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 303 * match type_pattern. 304 */ 305 void 306 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 307 int timeout_secs) 308 { 309 struct ssh_channels *sc = ssh->chanctxt; 310 311 debug2_f("channel type \"%s\" timeout %d seconds", 312 type_pattern, timeout_secs); 313 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 314 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 315 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 316 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 317 sc->ntimeouts++; 318 } 319 320 /* Clears all previously-added channel timeouts */ 321 void 322 channel_clear_timeouts(struct ssh *ssh) 323 { 324 struct ssh_channels *sc = ssh->chanctxt; 325 size_t i; 326 327 debug3_f("clearing"); 328 for (i = 0; i < sc->ntimeouts; i++) 329 free(sc->timeouts[i].type_pattern); 330 free(sc->timeouts); 331 sc->timeouts = NULL; 332 sc->ntimeouts = 0; 333 } 334 335 static int 336 lookup_timeout(struct ssh *ssh, const char *type) 337 { 338 struct ssh_channels *sc = ssh->chanctxt; 339 size_t i; 340 341 for (i = 0; i < sc->ntimeouts; i++) { 342 if (match_pattern(type, sc->timeouts[i].type_pattern)) 343 return sc->timeouts[i].timeout_secs; 344 } 345 346 return 0; 347 } 348 349 /* 350 * Sets "extended type" of a channel; used by session layer to add additional 351 * information about channel types (e.g. shell, login, subsystem) that can then 352 * be used to select timeouts. 353 * Will reset c->inactive_deadline as a side-effect. 354 */ 355 void 356 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 357 { 358 Channel *c; 359 360 if ((c = channel_by_id(ssh, id)) == NULL) 361 fatal_f("missing channel %d", id); 362 if (c->xctype != NULL) 363 free(c->xctype); 364 c->xctype = xstrdup(xctype); 365 /* Type has changed, so look up inactivity deadline again */ 366 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 367 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 368 c->inactive_deadline); 369 } 370 371 /* 372 * Register filedescriptors for a channel, used when allocating a channel or 373 * when the channel consumer/producer is ready, e.g. shell exec'd 374 */ 375 static void 376 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 377 int extusage, int nonblock, int is_tty) 378 { 379 int val; 380 381 if (rfd != -1) 382 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 383 if (wfd != -1 && wfd != rfd) 384 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 385 if (efd != -1 && efd != rfd && efd != wfd) 386 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 387 388 c->rfd = rfd; 389 c->wfd = wfd; 390 c->sock = (rfd == wfd) ? rfd : -1; 391 c->efd = efd; 392 c->extended_usage = extusage; 393 394 if ((c->isatty = is_tty) != 0) 395 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 396 397 /* enable nonblocking mode */ 398 c->restore_block = 0; 399 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 400 /* 401 * Special handling for stdio file descriptors: do not set 402 * non-blocking mode if they are TTYs. Otherwise prepare to 403 * restore their blocking state on exit to avoid interfering 404 * with other programs that follow. 405 */ 406 if (rfd != -1 && !isatty(rfd) && 407 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 408 c->restore_flags[0] = val; 409 c->restore_block |= CHANNEL_RESTORE_RFD; 410 set_nonblock(rfd); 411 } 412 if (wfd != -1 && !isatty(wfd) && 413 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 414 c->restore_flags[1] = val; 415 c->restore_block |= CHANNEL_RESTORE_WFD; 416 set_nonblock(wfd); 417 } 418 if (efd != -1 && !isatty(efd) && 419 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 420 c->restore_flags[2] = val; 421 c->restore_block |= CHANNEL_RESTORE_EFD; 422 set_nonblock(efd); 423 } 424 } else if (nonblock) { 425 if (rfd != -1) 426 set_nonblock(rfd); 427 if (wfd != -1) 428 set_nonblock(wfd); 429 if (efd != -1) 430 set_nonblock(efd); 431 } 432 } 433 434 /* 435 * Allocate a new channel object and set its type and socket. 436 */ 437 Channel * 438 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 439 u_int window, u_int maxpack, int extusage, const char *remote_name, 440 int nonblock) 441 { 442 struct ssh_channels *sc = ssh->chanctxt; 443 u_int i, found; 444 Channel *c; 445 int r; 446 447 /* Try to find a free slot where to put the new channel. */ 448 for (i = 0; i < sc->channels_alloc; i++) { 449 if (sc->channels[i] == NULL) { 450 /* Found a free slot. */ 451 found = i; 452 break; 453 } 454 } 455 if (i >= sc->channels_alloc) { 456 /* 457 * There are no free slots. Take last+1 slot and expand 458 * the array. 459 */ 460 found = sc->channels_alloc; 461 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 462 fatal_f("internal error: channels_alloc %d too big", 463 sc->channels_alloc); 464 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 465 sc->channels_alloc + 10, sizeof(*sc->channels)); 466 sc->channels_alloc += 10; 467 debug2("channel: expanding %d", sc->channels_alloc); 468 } 469 /* Initialize and return new channel. */ 470 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 471 if ((c->input = sshbuf_new()) == NULL || 472 (c->output = sshbuf_new()) == NULL || 473 (c->extended = sshbuf_new()) == NULL) 474 fatal_f("sshbuf_new failed"); 475 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 476 fatal_fr(r, "sshbuf_set_max_size"); 477 c->ostate = CHAN_OUTPUT_OPEN; 478 c->istate = CHAN_INPUT_OPEN; 479 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 480 c->self = found; 481 c->type = type; 482 c->ctype = ctype; 483 c->local_window = window; 484 c->local_window_max = window; 485 c->local_maxpacket = maxpack; 486 c->remote_name = xstrdup(remote_name); 487 c->ctl_chan = -1; 488 c->delayed = 1; /* prevent call to channel_post handler */ 489 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 490 TAILQ_INIT(&c->status_confirms); 491 debug("channel %d: new %s [%s] (inactive timeout: %u)", 492 found, c->ctype, remote_name, c->inactive_deadline); 493 return c; 494 } 495 496 int 497 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 498 { 499 int ret, fd = *fdp; 500 501 if (fd == -1) 502 return 0; 503 504 /* restore blocking */ 505 if (*fdp == c->rfd && 506 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 507 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 508 else if (*fdp == c->wfd && 509 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 510 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 511 else if (*fdp == c->efd && 512 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 513 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 514 515 if (*fdp == c->rfd) { 516 c->io_want &= ~SSH_CHAN_IO_RFD; 517 c->io_ready &= ~SSH_CHAN_IO_RFD; 518 c->rfd = -1; 519 c->pfds[0] = -1; 520 } 521 if (*fdp == c->wfd) { 522 c->io_want &= ~SSH_CHAN_IO_WFD; 523 c->io_ready &= ~SSH_CHAN_IO_WFD; 524 c->wfd = -1; 525 c->pfds[1] = -1; 526 } 527 if (*fdp == c->efd) { 528 c->io_want &= ~SSH_CHAN_IO_EFD; 529 c->io_ready &= ~SSH_CHAN_IO_EFD; 530 c->efd = -1; 531 c->pfds[2] = -1; 532 } 533 if (*fdp == c->sock) { 534 c->io_want &= ~SSH_CHAN_IO_SOCK; 535 c->io_ready &= ~SSH_CHAN_IO_SOCK; 536 c->sock = -1; 537 c->pfds[3] = -1; 538 } 539 540 ret = close(fd); 541 *fdp = -1; /* probably redundant */ 542 return ret; 543 } 544 545 /* Close all channel fd/socket. */ 546 static void 547 channel_close_fds(struct ssh *ssh, Channel *c) 548 { 549 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 550 551 channel_close_fd(ssh, c, &c->sock); 552 if (rfd != sock) 553 channel_close_fd(ssh, c, &c->rfd); 554 if (wfd != sock && wfd != rfd) 555 channel_close_fd(ssh, c, &c->wfd); 556 if (efd != sock && efd != rfd && efd != wfd) 557 channel_close_fd(ssh, c, &c->efd); 558 } 559 560 static void 561 fwd_perm_clear(struct permission *perm) 562 { 563 free(perm->host_to_connect); 564 free(perm->listen_host); 565 free(perm->listen_path); 566 memset(perm, 0, sizeof(*perm)); 567 } 568 569 /* Returns an printable name for the specified forwarding permission list */ 570 static const char * 571 fwd_ident(int who, int where) 572 { 573 if (who == FORWARD_ADM) { 574 if (where == FORWARD_LOCAL) 575 return "admin local"; 576 else if (where == FORWARD_REMOTE) 577 return "admin remote"; 578 } else if (who == FORWARD_USER) { 579 if (where == FORWARD_LOCAL) 580 return "user local"; 581 else if (where == FORWARD_REMOTE) 582 return "user remote"; 583 } 584 fatal("Unknown forward permission list %d/%d", who, where); 585 } 586 587 /* Returns the forwarding permission list for the specified direction */ 588 static struct permission_set * 589 permission_set_get(struct ssh *ssh, int where) 590 { 591 struct ssh_channels *sc = ssh->chanctxt; 592 593 switch (where) { 594 case FORWARD_LOCAL: 595 return &sc->local_perms; 596 break; 597 case FORWARD_REMOTE: 598 return &sc->remote_perms; 599 break; 600 default: 601 fatal_f("invalid forwarding direction %d", where); 602 } 603 } 604 605 /* Returns pointers to the specified forwarding list and its element count */ 606 static void 607 permission_set_get_array(struct ssh *ssh, int who, int where, 608 struct permission ***permpp, u_int **npermpp) 609 { 610 struct permission_set *pset = permission_set_get(ssh, where); 611 612 switch (who) { 613 case FORWARD_USER: 614 *permpp = &pset->permitted_user; 615 *npermpp = &pset->num_permitted_user; 616 break; 617 case FORWARD_ADM: 618 *permpp = &pset->permitted_admin; 619 *npermpp = &pset->num_permitted_admin; 620 break; 621 default: 622 fatal_f("invalid forwarding client %d", who); 623 } 624 } 625 626 /* Adds an entry to the specified forwarding list */ 627 static int 628 permission_set_add(struct ssh *ssh, int who, int where, 629 const char *host_to_connect, int port_to_connect, 630 const char *listen_host, const char *listen_path, int listen_port, 631 Channel *downstream) 632 { 633 struct permission **permp; 634 u_int n, *npermp; 635 636 permission_set_get_array(ssh, who, where, &permp, &npermp); 637 638 if (*npermp >= INT_MAX) 639 fatal_f("%s overflow", fwd_ident(who, where)); 640 641 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 642 n = (*npermp)++; 643 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 644 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 645 (*permp)[n].port_to_connect = port_to_connect; 646 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 647 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 648 (*permp)[n].listen_port = listen_port; 649 (*permp)[n].downstream = downstream; 650 #undef MAYBE_DUP 651 return (int)n; 652 } 653 654 static void 655 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 656 { 657 struct ssh_channels *sc = ssh->chanctxt; 658 struct permission_set *pset = &sc->local_perms; 659 struct permission *perm; 660 int r; 661 u_int i; 662 663 for (i = 0; i < pset->num_permitted_user; i++) { 664 perm = &pset->permitted_user[i]; 665 if (perm->downstream != c) 666 continue; 667 668 /* cancel on the server, since mux client is gone */ 669 debug("channel %d: cleanup remote forward for %s:%u", 670 c->self, perm->listen_host, perm->listen_port); 671 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 672 (r = sshpkt_put_cstring(ssh, 673 "cancel-tcpip-forward")) != 0 || 674 (r = sshpkt_put_u8(ssh, 0)) != 0 || 675 (r = sshpkt_put_cstring(ssh, 676 channel_rfwd_bind_host(perm->listen_host))) != 0 || 677 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 678 (r = sshpkt_send(ssh)) != 0) { 679 fatal_fr(r, "channel %i", c->self); 680 } 681 fwd_perm_clear(perm); /* unregister */ 682 } 683 } 684 685 /* Free the channel and close its fd/socket. */ 686 void 687 channel_free(struct ssh *ssh, Channel *c) 688 { 689 struct ssh_channels *sc = ssh->chanctxt; 690 char *s; 691 u_int i, n; 692 Channel *other; 693 struct channel_confirm *cc; 694 695 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 696 if ((other = sc->channels[i]) == NULL) 697 continue; 698 n++; 699 /* detach from mux client and prepare for closing */ 700 if (c->type == SSH_CHANNEL_MUX_CLIENT && 701 other->type == SSH_CHANNEL_MUX_PROXY && 702 other->mux_ctx == c) { 703 other->mux_ctx = NULL; 704 other->type = SSH_CHANNEL_OPEN; 705 other->istate = CHAN_INPUT_CLOSED; 706 other->ostate = CHAN_OUTPUT_CLOSED; 707 } 708 } 709 debug("channel %d: free: %s, nchannels %u", c->self, 710 c->remote_name ? c->remote_name : "???", n); 711 712 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 713 mux_remove_remote_forwardings(ssh, c); 714 free(c->mux_ctx); 715 c->mux_ctx = NULL; 716 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 717 free(c->mux_ctx); 718 c->mux_ctx = NULL; 719 } 720 721 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 722 s = channel_open_message(ssh); 723 debug3("channel %d: status: %s", c->self, s); 724 free(s); 725 } 726 727 channel_close_fds(ssh, c); 728 sshbuf_free(c->input); 729 sshbuf_free(c->output); 730 sshbuf_free(c->extended); 731 c->input = c->output = c->extended = NULL; 732 free(c->remote_name); 733 c->remote_name = NULL; 734 free(c->path); 735 c->path = NULL; 736 free(c->listening_addr); 737 c->listening_addr = NULL; 738 free(c->xctype); 739 c->xctype = NULL; 740 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 741 if (cc->abandon_cb != NULL) 742 cc->abandon_cb(ssh, c, cc->ctx); 743 TAILQ_REMOVE(&c->status_confirms, cc, entry); 744 freezero(cc, sizeof(*cc)); 745 } 746 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 747 c->filter_cleanup(ssh, c->self, c->filter_ctx); 748 sc->channels[c->self] = NULL; 749 freezero(c, sizeof(*c)); 750 } 751 752 void 753 channel_free_all(struct ssh *ssh) 754 { 755 u_int i; 756 struct ssh_channels *sc = ssh->chanctxt; 757 758 for (i = 0; i < sc->channels_alloc; i++) 759 if (sc->channels[i] != NULL) 760 channel_free(ssh, sc->channels[i]); 761 762 free(sc->channels); 763 sc->channels = NULL; 764 sc->channels_alloc = 0; 765 766 free(sc->x11_saved_display); 767 sc->x11_saved_display = NULL; 768 769 free(sc->x11_saved_proto); 770 sc->x11_saved_proto = NULL; 771 772 free(sc->x11_saved_data); 773 sc->x11_saved_data = NULL; 774 sc->x11_saved_data_len = 0; 775 776 free(sc->x11_fake_data); 777 sc->x11_fake_data = NULL; 778 sc->x11_fake_data_len = 0; 779 } 780 781 /* 782 * Closes the sockets/fds of all channels. This is used to close extra file 783 * descriptors after a fork. 784 */ 785 void 786 channel_close_all(struct ssh *ssh) 787 { 788 u_int i; 789 790 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 791 if (ssh->chanctxt->channels[i] != NULL) 792 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 793 } 794 795 /* 796 * Stop listening to channels. 797 */ 798 void 799 channel_stop_listening(struct ssh *ssh) 800 { 801 u_int i; 802 Channel *c; 803 804 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 805 c = ssh->chanctxt->channels[i]; 806 if (c != NULL) { 807 switch (c->type) { 808 case SSH_CHANNEL_AUTH_SOCKET: 809 case SSH_CHANNEL_PORT_LISTENER: 810 case SSH_CHANNEL_RPORT_LISTENER: 811 case SSH_CHANNEL_X11_LISTENER: 812 case SSH_CHANNEL_UNIX_LISTENER: 813 case SSH_CHANNEL_RUNIX_LISTENER: 814 channel_close_fd(ssh, c, &c->sock); 815 channel_free(ssh, c); 816 break; 817 } 818 } 819 } 820 } 821 822 /* 823 * Returns true if no channel has too much buffered data, and false if one or 824 * more channel is overfull. 825 */ 826 int 827 channel_not_very_much_buffered_data(struct ssh *ssh) 828 { 829 u_int i; 830 u_int maxsize = ssh_packet_get_maxsize(ssh); 831 Channel *c; 832 833 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 834 c = ssh->chanctxt->channels[i]; 835 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 836 continue; 837 if (sshbuf_len(c->output) > maxsize) { 838 debug2("channel %d: big output buffer %zu > %u", 839 c->self, sshbuf_len(c->output), maxsize); 840 return 0; 841 } 842 } 843 return 1; 844 } 845 846 /* Returns true if any channel is still open. */ 847 int 848 channel_still_open(struct ssh *ssh) 849 { 850 u_int i; 851 Channel *c; 852 853 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 854 c = ssh->chanctxt->channels[i]; 855 if (c == NULL) 856 continue; 857 switch (c->type) { 858 case SSH_CHANNEL_X11_LISTENER: 859 case SSH_CHANNEL_PORT_LISTENER: 860 case SSH_CHANNEL_RPORT_LISTENER: 861 case SSH_CHANNEL_MUX_LISTENER: 862 case SSH_CHANNEL_CLOSED: 863 case SSH_CHANNEL_AUTH_SOCKET: 864 case SSH_CHANNEL_DYNAMIC: 865 case SSH_CHANNEL_RDYNAMIC_OPEN: 866 case SSH_CHANNEL_CONNECTING: 867 case SSH_CHANNEL_ZOMBIE: 868 case SSH_CHANNEL_ABANDONED: 869 case SSH_CHANNEL_UNIX_LISTENER: 870 case SSH_CHANNEL_RUNIX_LISTENER: 871 continue; 872 case SSH_CHANNEL_LARVAL: 873 continue; 874 case SSH_CHANNEL_OPENING: 875 case SSH_CHANNEL_OPEN: 876 case SSH_CHANNEL_RDYNAMIC_FINISH: 877 case SSH_CHANNEL_X11_OPEN: 878 case SSH_CHANNEL_MUX_CLIENT: 879 case SSH_CHANNEL_MUX_PROXY: 880 return 1; 881 default: 882 fatal_f("bad channel type %d", c->type); 883 /* NOTREACHED */ 884 } 885 } 886 return 0; 887 } 888 889 /* Returns the id of an open channel suitable for keepaliving */ 890 int 891 channel_find_open(struct ssh *ssh) 892 { 893 u_int i; 894 Channel *c; 895 896 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 897 c = ssh->chanctxt->channels[i]; 898 if (c == NULL || !c->have_remote_id) 899 continue; 900 switch (c->type) { 901 case SSH_CHANNEL_CLOSED: 902 case SSH_CHANNEL_DYNAMIC: 903 case SSH_CHANNEL_RDYNAMIC_OPEN: 904 case SSH_CHANNEL_RDYNAMIC_FINISH: 905 case SSH_CHANNEL_X11_LISTENER: 906 case SSH_CHANNEL_PORT_LISTENER: 907 case SSH_CHANNEL_RPORT_LISTENER: 908 case SSH_CHANNEL_MUX_LISTENER: 909 case SSH_CHANNEL_MUX_CLIENT: 910 case SSH_CHANNEL_MUX_PROXY: 911 case SSH_CHANNEL_OPENING: 912 case SSH_CHANNEL_CONNECTING: 913 case SSH_CHANNEL_ZOMBIE: 914 case SSH_CHANNEL_ABANDONED: 915 case SSH_CHANNEL_UNIX_LISTENER: 916 case SSH_CHANNEL_RUNIX_LISTENER: 917 continue; 918 case SSH_CHANNEL_LARVAL: 919 case SSH_CHANNEL_AUTH_SOCKET: 920 case SSH_CHANNEL_OPEN: 921 case SSH_CHANNEL_X11_OPEN: 922 return i; 923 default: 924 fatal_f("bad channel type %d", c->type); 925 /* NOTREACHED */ 926 } 927 } 928 return -1; 929 } 930 931 /* Returns the state of the channel's extended usage flag */ 932 const char * 933 channel_format_extended_usage(const Channel *c) 934 { 935 if (c->efd == -1) 936 return "closed"; 937 938 switch (c->extended_usage) { 939 case CHAN_EXTENDED_WRITE: 940 return "write"; 941 case CHAN_EXTENDED_READ: 942 return "read"; 943 case CHAN_EXTENDED_IGNORE: 944 return "ignore"; 945 default: 946 return "UNKNOWN"; 947 } 948 } 949 950 static char * 951 channel_format_status(const Channel *c) 952 { 953 char *ret = NULL; 954 955 xasprintf(&ret, "t%d [%s] %s%u i%u/%zu o%u/%zu e[%s]/%zu " 956 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 957 c->type, c->xctype != NULL ? c->xctype : c->ctype, 958 c->have_remote_id ? "r" : "nr", c->remote_id, 959 c->istate, sshbuf_len(c->input), 960 c->ostate, sshbuf_len(c->output), 961 channel_format_extended_usage(c), sshbuf_len(c->extended), 962 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 963 c->io_want, c->io_ready); 964 return ret; 965 } 966 967 /* 968 * Returns a message describing the currently open forwarded connections, 969 * suitable for sending to the client. The message contains crlf pairs for 970 * newlines. 971 */ 972 char * 973 channel_open_message(struct ssh *ssh) 974 { 975 struct sshbuf *buf; 976 Channel *c; 977 u_int i; 978 int r; 979 char *cp, *ret; 980 981 if ((buf = sshbuf_new()) == NULL) 982 fatal_f("sshbuf_new"); 983 if ((r = sshbuf_putf(buf, 984 "The following connections are open:\r\n")) != 0) 985 fatal_fr(r, "sshbuf_putf"); 986 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 987 c = ssh->chanctxt->channels[i]; 988 if (c == NULL) 989 continue; 990 switch (c->type) { 991 case SSH_CHANNEL_X11_LISTENER: 992 case SSH_CHANNEL_PORT_LISTENER: 993 case SSH_CHANNEL_RPORT_LISTENER: 994 case SSH_CHANNEL_CLOSED: 995 case SSH_CHANNEL_AUTH_SOCKET: 996 case SSH_CHANNEL_ZOMBIE: 997 case SSH_CHANNEL_ABANDONED: 998 case SSH_CHANNEL_MUX_LISTENER: 999 case SSH_CHANNEL_UNIX_LISTENER: 1000 case SSH_CHANNEL_RUNIX_LISTENER: 1001 continue; 1002 case SSH_CHANNEL_LARVAL: 1003 case SSH_CHANNEL_OPENING: 1004 case SSH_CHANNEL_CONNECTING: 1005 case SSH_CHANNEL_DYNAMIC: 1006 case SSH_CHANNEL_RDYNAMIC_OPEN: 1007 case SSH_CHANNEL_RDYNAMIC_FINISH: 1008 case SSH_CHANNEL_OPEN: 1009 case SSH_CHANNEL_X11_OPEN: 1010 case SSH_CHANNEL_MUX_PROXY: 1011 case SSH_CHANNEL_MUX_CLIENT: 1012 cp = channel_format_status(c); 1013 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1014 c->self, c->remote_name, cp)) != 0) { 1015 free(cp); 1016 fatal_fr(r, "sshbuf_putf"); 1017 } 1018 free(cp); 1019 continue; 1020 default: 1021 fatal_f("bad channel type %d", c->type); 1022 /* NOTREACHED */ 1023 } 1024 } 1025 if ((ret = sshbuf_dup_string(buf)) == NULL) 1026 fatal_f("sshbuf_dup_string"); 1027 sshbuf_free(buf); 1028 return ret; 1029 } 1030 1031 static void 1032 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1033 { 1034 int r; 1035 1036 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1037 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1038 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1039 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1040 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1041 fatal_r(r, "%s: channel %i: open", where, c->self); 1042 } 1043 } 1044 1045 void 1046 channel_send_open(struct ssh *ssh, int id) 1047 { 1048 Channel *c = channel_lookup(ssh, id); 1049 int r; 1050 1051 if (c == NULL) { 1052 logit("channel_send_open: %d: bad id", id); 1053 return; 1054 } 1055 debug2("channel %d: send open", id); 1056 open_preamble(ssh, __func__, c, c->ctype); 1057 if ((r = sshpkt_send(ssh)) != 0) 1058 fatal_fr(r, "channel %i", c->self); 1059 } 1060 1061 void 1062 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 1063 { 1064 Channel *c = channel_lookup(ssh, id); 1065 int r; 1066 1067 if (c == NULL) { 1068 logit_f("%d: unknown channel id", id); 1069 return; 1070 } 1071 if (!c->have_remote_id) 1072 fatal_f("channel %d: no remote id", c->self); 1073 1074 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1075 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1076 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1077 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1078 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1079 fatal_fr(r, "channel %i", c->self); 1080 } 1081 } 1082 1083 void 1084 channel_register_status_confirm(struct ssh *ssh, int id, 1085 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1086 { 1087 struct channel_confirm *cc; 1088 Channel *c; 1089 1090 if ((c = channel_lookup(ssh, id)) == NULL) 1091 fatal_f("%d: bad id", id); 1092 1093 cc = xcalloc(1, sizeof(*cc)); 1094 cc->cb = cb; 1095 cc->abandon_cb = abandon_cb; 1096 cc->ctx = ctx; 1097 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1098 } 1099 1100 void 1101 channel_register_open_confirm(struct ssh *ssh, int id, 1102 channel_open_fn *fn, void *ctx) 1103 { 1104 Channel *c = channel_lookup(ssh, id); 1105 1106 if (c == NULL) { 1107 logit_f("%d: bad id", id); 1108 return; 1109 } 1110 c->open_confirm = fn; 1111 c->open_confirm_ctx = ctx; 1112 } 1113 1114 void 1115 channel_register_cleanup(struct ssh *ssh, int id, 1116 channel_callback_fn *fn, int do_close) 1117 { 1118 Channel *c = channel_by_id(ssh, id); 1119 1120 if (c == NULL) { 1121 logit_f("%d: bad id", id); 1122 return; 1123 } 1124 c->detach_user = fn; 1125 c->detach_close = do_close; 1126 } 1127 1128 void 1129 channel_cancel_cleanup(struct ssh *ssh, int id) 1130 { 1131 Channel *c = channel_by_id(ssh, id); 1132 1133 if (c == NULL) { 1134 logit_f("%d: bad id", id); 1135 return; 1136 } 1137 c->detach_user = NULL; 1138 c->detach_close = 0; 1139 } 1140 1141 void 1142 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1143 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1144 { 1145 Channel *c = channel_lookup(ssh, id); 1146 1147 if (c == NULL) { 1148 logit_f("%d: bad id", id); 1149 return; 1150 } 1151 c->input_filter = ifn; 1152 c->output_filter = ofn; 1153 c->filter_ctx = ctx; 1154 c->filter_cleanup = cfn; 1155 } 1156 1157 void 1158 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1159 int extusage, int nonblock, int is_tty, u_int window_max) 1160 { 1161 Channel *c = channel_lookup(ssh, id); 1162 int r; 1163 1164 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1165 fatal("channel_activate for non-larval channel %d.", id); 1166 if (!c->have_remote_id) 1167 fatal_f("channel %d: no remote id", c->self); 1168 1169 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1170 c->type = SSH_CHANNEL_OPEN; 1171 c->lastused = monotime(); 1172 c->local_window = c->local_window_max = window_max; 1173 1174 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1175 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1176 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1177 (r = sshpkt_send(ssh)) != 0) 1178 fatal_fr(r, "channel %i", c->self); 1179 } 1180 1181 static void 1182 channel_pre_listener(struct ssh *ssh, Channel *c) 1183 { 1184 c->io_want = SSH_CHAN_IO_SOCK_R; 1185 } 1186 1187 static void 1188 channel_pre_connecting(struct ssh *ssh, Channel *c) 1189 { 1190 debug3("channel %d: waiting for connection", c->self); 1191 c->io_want = SSH_CHAN_IO_SOCK_W; 1192 } 1193 1194 static void 1195 channel_pre_open(struct ssh *ssh, Channel *c) 1196 { 1197 c->io_want = 0; 1198 if (c->istate == CHAN_INPUT_OPEN && 1199 c->remote_window > 0 && 1200 sshbuf_len(c->input) < c->remote_window && 1201 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1202 c->io_want |= SSH_CHAN_IO_RFD; 1203 if (c->ostate == CHAN_OUTPUT_OPEN || 1204 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1205 if (sshbuf_len(c->output) > 0) { 1206 c->io_want |= SSH_CHAN_IO_WFD; 1207 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1208 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1209 debug2("channel %d: " 1210 "obuf_empty delayed efd %d/(%zu)", c->self, 1211 c->efd, sshbuf_len(c->extended)); 1212 else 1213 chan_obuf_empty(ssh, c); 1214 } 1215 } 1216 /** XXX check close conditions, too */ 1217 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1218 c->ostate == CHAN_OUTPUT_CLOSED)) { 1219 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1220 sshbuf_len(c->extended) > 0) 1221 c->io_want |= SSH_CHAN_IO_EFD_W; 1222 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1223 (c->extended_usage == CHAN_EXTENDED_READ || 1224 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1225 sshbuf_len(c->extended) < c->remote_window) 1226 c->io_want |= SSH_CHAN_IO_EFD_R; 1227 } 1228 /* XXX: What about efd? races? */ 1229 } 1230 1231 /* 1232 * This is a special state for X11 authentication spoofing. An opened X11 1233 * connection (when authentication spoofing is being done) remains in this 1234 * state until the first packet has been completely read. The authentication 1235 * data in that packet is then substituted by the real data if it matches the 1236 * fake data, and the channel is put into normal mode. 1237 * XXX All this happens at the client side. 1238 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1239 */ 1240 static int 1241 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1242 { 1243 struct ssh_channels *sc = ssh->chanctxt; 1244 u_char *ucp; 1245 u_int proto_len, data_len; 1246 1247 /* Is this being called after the refusal deadline? */ 1248 if (sc->x11_refuse_time != 0 && 1249 monotime() >= sc->x11_refuse_time) { 1250 verbose("Rejected X11 connection after ForwardX11Timeout " 1251 "expired"); 1252 return -1; 1253 } 1254 1255 /* Check if the fixed size part of the packet is in buffer. */ 1256 if (sshbuf_len(b) < 12) 1257 return 0; 1258 1259 /* Parse the lengths of variable-length fields. */ 1260 ucp = sshbuf_mutable_ptr(b); 1261 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1262 proto_len = 256 * ucp[6] + ucp[7]; 1263 data_len = 256 * ucp[8] + ucp[9]; 1264 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1265 proto_len = ucp[6] + 256 * ucp[7]; 1266 data_len = ucp[8] + 256 * ucp[9]; 1267 } else { 1268 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1269 ucp[0]); 1270 return -1; 1271 } 1272 1273 /* Check if the whole packet is in buffer. */ 1274 if (sshbuf_len(b) < 1275 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1276 return 0; 1277 1278 /* Check if authentication protocol matches. */ 1279 if (proto_len != strlen(sc->x11_saved_proto) || 1280 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1281 debug2("X11 connection uses different authentication protocol."); 1282 return -1; 1283 } 1284 /* Check if authentication data matches our fake data. */ 1285 if (data_len != sc->x11_fake_data_len || 1286 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1287 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1288 debug2("X11 auth data does not match fake data."); 1289 return -1; 1290 } 1291 /* Check fake data length */ 1292 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1293 error("X11 fake_data_len %d != saved_data_len %d", 1294 sc->x11_fake_data_len, sc->x11_saved_data_len); 1295 return -1; 1296 } 1297 /* 1298 * Received authentication protocol and data match 1299 * our fake data. Substitute the fake data with real 1300 * data. 1301 */ 1302 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1303 sc->x11_saved_data, sc->x11_saved_data_len); 1304 return 1; 1305 } 1306 1307 void 1308 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1309 { 1310 debug3_f("channel %d: forcibly closing", c->self); 1311 if (c->istate == CHAN_INPUT_OPEN) 1312 chan_read_failed(ssh, c); 1313 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1314 sshbuf_reset(c->input); 1315 chan_ibuf_empty(ssh, c); 1316 } 1317 if (c->ostate == CHAN_OUTPUT_OPEN || 1318 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1319 sshbuf_reset(c->output); 1320 chan_write_failed(ssh, c); 1321 } 1322 if (c->detach_user) 1323 c->detach_user(ssh, c->self, 1, NULL); 1324 if (c->efd != -1) 1325 channel_close_fd(ssh, c, &c->efd); 1326 if (abandon) 1327 c->type = SSH_CHANNEL_ABANDONED; 1328 /* exempt from inactivity timeouts */ 1329 c->inactive_deadline = 0; 1330 c->lastused = 0; 1331 } 1332 1333 static void 1334 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1335 { 1336 int ret = x11_open_helper(ssh, c->output); 1337 1338 /* c->force_drain = 1; */ 1339 1340 if (ret == 1) { 1341 c->type = SSH_CHANNEL_OPEN; 1342 c->lastused = monotime(); 1343 channel_pre_open(ssh, c); 1344 } else if (ret == -1) { 1345 logit("X11 connection rejected because of wrong " 1346 "authentication."); 1347 debug2("X11 rejected %d i%d/o%d", 1348 c->self, c->istate, c->ostate); 1349 channel_force_close(ssh, c, 0); 1350 } 1351 } 1352 1353 static void 1354 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1355 { 1356 c->io_want = 0; 1357 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1358 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1359 c->io_want |= SSH_CHAN_IO_RFD; 1360 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1361 /* clear buffer immediately (discard any partial packet) */ 1362 sshbuf_reset(c->input); 1363 chan_ibuf_empty(ssh, c); 1364 /* Start output drain. XXX just kill chan? */ 1365 chan_rcvd_oclose(ssh, c); 1366 } 1367 if (c->ostate == CHAN_OUTPUT_OPEN || 1368 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1369 if (sshbuf_len(c->output) > 0) 1370 c->io_want |= SSH_CHAN_IO_WFD; 1371 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1372 chan_obuf_empty(ssh, c); 1373 } 1374 } 1375 1376 /* try to decode a socks4 header */ 1377 static int 1378 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1379 { 1380 const u_char *p; 1381 char *host; 1382 u_int len, have, i, found, need; 1383 char username[256]; 1384 struct { 1385 u_int8_t version; 1386 u_int8_t command; 1387 u_int16_t dest_port; 1388 struct in_addr dest_addr; 1389 } s4_req, s4_rsp; 1390 int r; 1391 1392 debug2("channel %d: decode socks4", c->self); 1393 1394 have = sshbuf_len(input); 1395 len = sizeof(s4_req); 1396 if (have < len) 1397 return 0; 1398 p = sshbuf_ptr(input); 1399 1400 need = 1; 1401 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1402 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1403 debug2("channel %d: socks4a request", c->self); 1404 /* ... and needs an extra string (the hostname) */ 1405 need = 2; 1406 } 1407 /* Check for terminating NUL on the string(s) */ 1408 for (found = 0, i = len; i < have; i++) { 1409 if (p[i] == '\0') { 1410 found++; 1411 if (found == need) 1412 break; 1413 } 1414 if (i > 1024) { 1415 /* the peer is probably sending garbage */ 1416 debug("channel %d: decode socks4: too long", 1417 c->self); 1418 return -1; 1419 } 1420 } 1421 if (found < need) 1422 return 0; 1423 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1424 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1425 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1426 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1427 debug_r(r, "channels %d: decode socks4", c->self); 1428 return -1; 1429 } 1430 have = sshbuf_len(input); 1431 p = sshbuf_ptr(input); 1432 if (memchr(p, '\0', have) == NULL) { 1433 error("channel %d: decode socks4: unterminated user", c->self); 1434 return -1; 1435 } 1436 len = strlen(p); 1437 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1438 len++; /* trailing '\0' */ 1439 strlcpy(username, p, sizeof(username)); 1440 if ((r = sshbuf_consume(input, len)) != 0) 1441 fatal_fr(r, "channel %d: consume", c->self); 1442 free(c->path); 1443 c->path = NULL; 1444 if (need == 1) { /* SOCKS4: one string */ 1445 host = inet_ntoa(s4_req.dest_addr); 1446 c->path = xstrdup(host); 1447 } else { /* SOCKS4A: two strings */ 1448 have = sshbuf_len(input); 1449 p = sshbuf_ptr(input); 1450 if (memchr(p, '\0', have) == NULL) { 1451 error("channel %d: decode socks4a: host not nul " 1452 "terminated", c->self); 1453 return -1; 1454 } 1455 len = strlen(p); 1456 debug2("channel %d: decode socks4a: host %s/%d", 1457 c->self, p, len); 1458 len++; /* trailing '\0' */ 1459 if (len > NI_MAXHOST) { 1460 error("channel %d: hostname \"%.100s\" too long", 1461 c->self, p); 1462 return -1; 1463 } 1464 c->path = xstrdup(p); 1465 if ((r = sshbuf_consume(input, len)) != 0) 1466 fatal_fr(r, "channel %d: consume", c->self); 1467 } 1468 c->host_port = ntohs(s4_req.dest_port); 1469 1470 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1471 c->self, c->path, c->host_port, s4_req.command); 1472 1473 if (s4_req.command != 1) { 1474 debug("channel %d: cannot handle: %s cn %d", 1475 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1476 return -1; 1477 } 1478 s4_rsp.version = 0; /* vn: 0 for reply */ 1479 s4_rsp.command = 90; /* cd: req granted */ 1480 s4_rsp.dest_port = 0; /* ignored */ 1481 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1482 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1483 fatal_fr(r, "channel %d: append reply", c->self); 1484 return 1; 1485 } 1486 1487 /* try to decode a socks5 header */ 1488 #define SSH_SOCKS5_AUTHDONE 0x1000 1489 #define SSH_SOCKS5_NOAUTH 0x00 1490 #define SSH_SOCKS5_IPV4 0x01 1491 #define SSH_SOCKS5_DOMAIN 0x03 1492 #define SSH_SOCKS5_IPV6 0x04 1493 #define SSH_SOCKS5_CONNECT 0x01 1494 #define SSH_SOCKS5_SUCCESS 0x00 1495 1496 static int 1497 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1498 { 1499 /* XXX use get/put_u8 instead of trusting struct padding */ 1500 struct { 1501 u_int8_t version; 1502 u_int8_t command; 1503 u_int8_t reserved; 1504 u_int8_t atyp; 1505 } s5_req, s5_rsp; 1506 u_int16_t dest_port; 1507 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1508 const u_char *p; 1509 u_int have, need, i, found, nmethods, addrlen, af; 1510 int r; 1511 1512 debug2("channel %d: decode socks5", c->self); 1513 p = sshbuf_ptr(input); 1514 if (p[0] != 0x05) 1515 return -1; 1516 have = sshbuf_len(input); 1517 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1518 /* format: ver | nmethods | methods */ 1519 if (have < 2) 1520 return 0; 1521 nmethods = p[1]; 1522 if (have < nmethods + 2) 1523 return 0; 1524 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1525 for (found = 0, i = 2; i < nmethods + 2; i++) { 1526 if (p[i] == SSH_SOCKS5_NOAUTH) { 1527 found = 1; 1528 break; 1529 } 1530 } 1531 if (!found) { 1532 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1533 c->self); 1534 return -1; 1535 } 1536 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1537 fatal_fr(r, "channel %d: consume", c->self); 1538 /* version, method */ 1539 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1540 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1541 fatal_fr(r, "channel %d: append reply", c->self); 1542 c->flags |= SSH_SOCKS5_AUTHDONE; 1543 debug2("channel %d: socks5 auth done", c->self); 1544 return 0; /* need more */ 1545 } 1546 debug2("channel %d: socks5 post auth", c->self); 1547 if (have < sizeof(s5_req)+1) 1548 return 0; /* need more */ 1549 memcpy(&s5_req, p, sizeof(s5_req)); 1550 if (s5_req.version != 0x05 || 1551 s5_req.command != SSH_SOCKS5_CONNECT || 1552 s5_req.reserved != 0x00) { 1553 debug2("channel %d: only socks5 connect supported", c->self); 1554 return -1; 1555 } 1556 switch (s5_req.atyp){ 1557 case SSH_SOCKS5_IPV4: 1558 addrlen = 4; 1559 af = AF_INET; 1560 break; 1561 case SSH_SOCKS5_DOMAIN: 1562 addrlen = p[sizeof(s5_req)]; 1563 af = -1; 1564 break; 1565 case SSH_SOCKS5_IPV6: 1566 addrlen = 16; 1567 af = AF_INET6; 1568 break; 1569 default: 1570 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1571 return -1; 1572 } 1573 need = sizeof(s5_req) + addrlen + 2; 1574 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1575 need++; 1576 if (have < need) 1577 return 0; 1578 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1579 fatal_fr(r, "channel %d: consume", c->self); 1580 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1581 /* host string length */ 1582 if ((r = sshbuf_consume(input, 1)) != 0) 1583 fatal_fr(r, "channel %d: consume", c->self); 1584 } 1585 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1586 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1587 debug_r(r, "channel %d: parse addr/port", c->self); 1588 return -1; 1589 } 1590 dest_addr[addrlen] = '\0'; 1591 free(c->path); 1592 c->path = NULL; 1593 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1594 if (addrlen >= NI_MAXHOST) { 1595 error("channel %d: dynamic request: socks5 hostname " 1596 "\"%.100s\" too long", c->self, dest_addr); 1597 return -1; 1598 } 1599 c->path = xstrdup(dest_addr); 1600 } else { 1601 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1602 return -1; 1603 c->path = xstrdup(ntop); 1604 } 1605 c->host_port = ntohs(dest_port); 1606 1607 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1608 c->self, c->path, c->host_port, s5_req.command); 1609 1610 s5_rsp.version = 0x05; 1611 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1612 s5_rsp.reserved = 0; /* ignored */ 1613 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1614 dest_port = 0; /* ignored */ 1615 1616 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1617 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1618 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1619 fatal_fr(r, "channel %d: append reply", c->self); 1620 return 1; 1621 } 1622 1623 Channel * 1624 channel_connect_stdio_fwd(struct ssh *ssh, 1625 const char *host_to_connect, int port_to_connect, 1626 int in, int out, int nonblock) 1627 { 1628 Channel *c; 1629 1630 debug_f("%s:%d", host_to_connect, port_to_connect); 1631 1632 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1633 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1634 0, "stdio-forward", nonblock); 1635 1636 c->path = xstrdup(host_to_connect); 1637 c->host_port = port_to_connect; 1638 c->listening_port = 0; 1639 c->force_drain = 1; 1640 1641 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1642 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1643 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1644 1645 return c; 1646 } 1647 1648 /* dynamic port forwarding */ 1649 static void 1650 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1651 { 1652 const u_char *p; 1653 u_int have; 1654 int ret; 1655 1656 c->io_want = 0; 1657 have = sshbuf_len(c->input); 1658 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1659 /* sshbuf_dump(c->input, stderr); */ 1660 /* check if the fixed size part of the packet is in buffer. */ 1661 if (have < 3) { 1662 /* need more */ 1663 c->io_want |= SSH_CHAN_IO_RFD; 1664 return; 1665 } 1666 /* try to guess the protocol */ 1667 p = sshbuf_ptr(c->input); 1668 /* XXX sshbuf_peek_u8? */ 1669 switch (p[0]) { 1670 case 0x04: 1671 ret = channel_decode_socks4(c, c->input, c->output); 1672 break; 1673 case 0x05: 1674 ret = channel_decode_socks5(c, c->input, c->output); 1675 break; 1676 default: 1677 ret = -1; 1678 break; 1679 } 1680 if (ret < 0) { 1681 chan_mark_dead(ssh, c); 1682 } else if (ret == 0) { 1683 debug2("channel %d: pre_dynamic: need more", c->self); 1684 /* need more */ 1685 c->io_want |= SSH_CHAN_IO_RFD; 1686 if (sshbuf_len(c->output)) 1687 c->io_want |= SSH_CHAN_IO_WFD; 1688 } else { 1689 /* switch to the next state */ 1690 c->type = SSH_CHANNEL_OPENING; 1691 port_open_helper(ssh, c, "direct-tcpip"); 1692 } 1693 } 1694 1695 /* simulate read-error */ 1696 static void 1697 rdynamic_close(struct ssh *ssh, Channel *c) 1698 { 1699 c->type = SSH_CHANNEL_OPEN; 1700 channel_force_close(ssh, c, 0); 1701 } 1702 1703 /* reverse dynamic port forwarding */ 1704 static void 1705 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1706 { 1707 const u_char *p; 1708 u_int have, len; 1709 int r, ret; 1710 1711 have = sshbuf_len(c->output); 1712 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1713 /* sshbuf_dump(c->output, stderr); */ 1714 /* EOF received */ 1715 if (c->flags & CHAN_EOF_RCVD) { 1716 if ((r = sshbuf_consume(c->output, have)) != 0) 1717 fatal_fr(r, "channel %d: consume", c->self); 1718 rdynamic_close(ssh, c); 1719 return; 1720 } 1721 /* check if the fixed size part of the packet is in buffer. */ 1722 if (have < 3) 1723 return; 1724 /* try to guess the protocol */ 1725 p = sshbuf_ptr(c->output); 1726 switch (p[0]) { 1727 case 0x04: 1728 /* switch input/output for reverse forwarding */ 1729 ret = channel_decode_socks4(c, c->output, c->input); 1730 break; 1731 case 0x05: 1732 ret = channel_decode_socks5(c, c->output, c->input); 1733 break; 1734 default: 1735 ret = -1; 1736 break; 1737 } 1738 if (ret < 0) { 1739 rdynamic_close(ssh, c); 1740 } else if (ret == 0) { 1741 debug2("channel %d: pre_rdynamic: need more", c->self); 1742 /* send socks request to peer */ 1743 len = sshbuf_len(c->input); 1744 if (len > 0 && len < c->remote_window) { 1745 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1746 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1747 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1748 (r = sshpkt_send(ssh)) != 0) { 1749 fatal_fr(r, "channel %i: rdynamic", c->self); 1750 } 1751 if ((r = sshbuf_consume(c->input, len)) != 0) 1752 fatal_fr(r, "channel %d: consume", c->self); 1753 c->remote_window -= len; 1754 } 1755 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1756 /* the connect failed */ 1757 rdynamic_close(ssh, c); 1758 } 1759 } 1760 1761 /* This is our fake X11 server socket. */ 1762 static void 1763 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1764 { 1765 Channel *nc; 1766 struct sockaddr_storage addr; 1767 int r, newsock, oerrno, remote_port; 1768 socklen_t addrlen; 1769 char buf[16384], *remote_ipaddr; 1770 1771 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1772 return; 1773 1774 debug("X11 connection requested."); 1775 addrlen = sizeof(addr); 1776 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1777 if (c->single_connection) { 1778 oerrno = errno; 1779 debug2("single_connection: closing X11 listener."); 1780 channel_close_fd(ssh, c, &c->sock); 1781 chan_mark_dead(ssh, c); 1782 errno = oerrno; 1783 } 1784 if (newsock == -1) { 1785 if (errno != EINTR && errno != EWOULDBLOCK && 1786 errno != ECONNABORTED) 1787 error("accept: %.100s", strerror(errno)); 1788 if (errno == EMFILE || errno == ENFILE) 1789 c->notbefore = monotime() + 1; 1790 return; 1791 } 1792 set_nodelay(newsock); 1793 remote_ipaddr = get_peer_ipaddr(newsock); 1794 remote_port = get_peer_port(newsock); 1795 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1796 remote_ipaddr, remote_port); 1797 1798 nc = channel_new(ssh, "x11-connection", 1799 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1800 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1801 open_preamble(ssh, __func__, nc, "x11"); 1802 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1803 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1804 fatal_fr(r, "channel %i: reply", c->self); 1805 } 1806 if ((r = sshpkt_send(ssh)) != 0) 1807 fatal_fr(r, "channel %i: send", c->self); 1808 free(remote_ipaddr); 1809 } 1810 1811 static void 1812 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1813 { 1814 char *local_ipaddr = get_local_ipaddr(c->sock); 1815 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1816 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1817 int remote_port = get_peer_port(c->sock); 1818 int r; 1819 1820 if (remote_port == -1) { 1821 /* Fake addr/port to appease peers that validate it (Tectia) */ 1822 free(remote_ipaddr); 1823 remote_ipaddr = xstrdup("127.0.0.1"); 1824 remote_port = 65535; 1825 } 1826 1827 free(c->remote_name); 1828 xasprintf(&c->remote_name, 1829 "%s: listening port %d for %.100s port %d, " 1830 "connect from %.200s port %d to %.100s port %d", 1831 rtype, c->listening_port, c->path, c->host_port, 1832 remote_ipaddr, remote_port, local_ipaddr, local_port); 1833 1834 open_preamble(ssh, __func__, c, rtype); 1835 if (strcmp(rtype, "direct-tcpip") == 0) { 1836 /* target host, port */ 1837 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1838 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1839 fatal_fr(r, "channel %i: reply", c->self); 1840 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1841 /* target path */ 1842 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1843 fatal_fr(r, "channel %i: reply", c->self); 1844 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1845 /* listen path */ 1846 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1847 fatal_fr(r, "channel %i: reply", c->self); 1848 } else { 1849 /* listen address, port */ 1850 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1851 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1852 fatal_fr(r, "channel %i: reply", c->self); 1853 } 1854 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1855 /* reserved for future owner/mode info */ 1856 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1857 fatal_fr(r, "channel %i: reply", c->self); 1858 } else { 1859 /* originator host and port */ 1860 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1861 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1862 fatal_fr(r, "channel %i: reply", c->self); 1863 } 1864 if ((r = sshpkt_send(ssh)) != 0) 1865 fatal_fr(r, "channel %i: send", c->self); 1866 free(remote_ipaddr); 1867 free(local_ipaddr); 1868 } 1869 1870 void 1871 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1872 { 1873 ssh->chanctxt->x11_refuse_time = refuse_time; 1874 } 1875 1876 /* 1877 * This socket is listening for connections to a forwarded TCP/IP port. 1878 */ 1879 static void 1880 channel_post_port_listener(struct ssh *ssh, Channel *c) 1881 { 1882 Channel *nc; 1883 struct sockaddr_storage addr; 1884 int newsock, nextstate; 1885 socklen_t addrlen; 1886 char *rtype; 1887 1888 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1889 return; 1890 1891 debug("Connection to port %d forwarding to %.100s port %d requested.", 1892 c->listening_port, c->path, c->host_port); 1893 1894 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1895 nextstate = SSH_CHANNEL_OPENING; 1896 rtype = "forwarded-tcpip"; 1897 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1898 nextstate = SSH_CHANNEL_OPENING; 1899 rtype = "forwarded-streamlocal@openssh.com"; 1900 } else if (c->host_port == PORT_STREAMLOCAL) { 1901 nextstate = SSH_CHANNEL_OPENING; 1902 rtype = "direct-streamlocal@openssh.com"; 1903 } else if (c->host_port == 0) { 1904 nextstate = SSH_CHANNEL_DYNAMIC; 1905 rtype = "dynamic-tcpip"; 1906 } else { 1907 nextstate = SSH_CHANNEL_OPENING; 1908 rtype = "direct-tcpip"; 1909 } 1910 1911 addrlen = sizeof(addr); 1912 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1913 if (newsock == -1) { 1914 if (errno != EINTR && errno != EWOULDBLOCK && 1915 errno != ECONNABORTED) 1916 error("accept: %.100s", strerror(errno)); 1917 if (errno == EMFILE || errno == ENFILE) 1918 c->notbefore = monotime() + 1; 1919 return; 1920 } 1921 if (c->host_port != PORT_STREAMLOCAL) 1922 set_nodelay(newsock); 1923 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1924 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1925 nc->listening_port = c->listening_port; 1926 nc->host_port = c->host_port; 1927 if (c->path != NULL) 1928 nc->path = xstrdup(c->path); 1929 1930 if (nextstate != SSH_CHANNEL_DYNAMIC) 1931 port_open_helper(ssh, nc, rtype); 1932 } 1933 1934 /* 1935 * This is the authentication agent socket listening for connections from 1936 * clients. 1937 */ 1938 static void 1939 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1940 { 1941 Channel *nc; 1942 int r, newsock; 1943 struct sockaddr_storage addr; 1944 socklen_t addrlen; 1945 1946 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1947 return; 1948 1949 addrlen = sizeof(addr); 1950 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1951 if (newsock == -1) { 1952 error("accept from auth socket: %.100s", strerror(errno)); 1953 if (errno == EMFILE || errno == ENFILE) 1954 c->notbefore = monotime() + 1; 1955 return; 1956 } 1957 nc = channel_new(ssh, "agent-connection", 1958 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1959 c->local_window_max, c->local_maxpacket, 1960 0, "accepted auth socket", 1); 1961 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1962 if ((r = sshpkt_send(ssh)) != 0) 1963 fatal_fr(r, "channel %i", c->self); 1964 } 1965 1966 static void 1967 channel_post_connecting(struct ssh *ssh, Channel *c) 1968 { 1969 int err = 0, sock, isopen, r; 1970 socklen_t sz = sizeof(err); 1971 1972 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 1973 return; 1974 if (!c->have_remote_id) 1975 fatal_f("channel %d: no remote id", c->self); 1976 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1977 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1978 1979 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 1980 err = errno; 1981 error("getsockopt SO_ERROR failed"); 1982 } 1983 1984 if (err == 0) { 1985 /* Non-blocking connection completed */ 1986 debug("channel %d: connected to %s port %d", 1987 c->self, c->connect_ctx.host, c->connect_ctx.port); 1988 channel_connect_ctx_free(&c->connect_ctx); 1989 c->type = SSH_CHANNEL_OPEN; 1990 c->lastused = monotime(); 1991 if (isopen) { 1992 /* no message necessary */ 1993 } else { 1994 if ((r = sshpkt_start(ssh, 1995 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1996 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1997 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1998 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1999 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2000 (r = sshpkt_send(ssh)) != 0) 2001 fatal_fr(r, "channel %i open confirm", c->self); 2002 } 2003 return; 2004 } 2005 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2006 return; 2007 2008 /* Non-blocking connection failed */ 2009 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2010 2011 /* Try next address, if any */ 2012 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2013 /* Exhausted all addresses for this destination */ 2014 error("connect_to %.100s port %d: failed.", 2015 c->connect_ctx.host, c->connect_ctx.port); 2016 channel_connect_ctx_free(&c->connect_ctx); 2017 if (isopen) { 2018 rdynamic_close(ssh, c); 2019 } else { 2020 if ((r = sshpkt_start(ssh, 2021 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2022 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2023 (r = sshpkt_put_u32(ssh, 2024 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2025 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2026 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2027 (r = sshpkt_send(ssh)) != 0) 2028 fatal_fr(r, "channel %i: failure", c->self); 2029 chan_mark_dead(ssh, c); 2030 } 2031 } 2032 2033 /* New non-blocking connection in progress */ 2034 close(c->sock); 2035 c->sock = c->rfd = c->wfd = sock; 2036 } 2037 2038 static int 2039 channel_handle_rfd(struct ssh *ssh, Channel *c) 2040 { 2041 char buf[CHAN_RBUF]; 2042 ssize_t len; 2043 int r; 2044 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2045 2046 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2047 return 1; /* Shouldn't happen */ 2048 if ((avail = sshbuf_avail(c->input)) == 0) 2049 return 1; /* Shouldn't happen */ 2050 2051 /* 2052 * For "simple" channels (i.e. not datagram or filtered), we can 2053 * read directly to the channel buffer. 2054 */ 2055 if (c->input_filter == NULL && !c->datagram) { 2056 /* Only OPEN channels have valid rwin */ 2057 if (c->type == SSH_CHANNEL_OPEN) { 2058 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2059 return 1; /* shouldn't happen */ 2060 if (maxlen > c->remote_window - have) 2061 maxlen = c->remote_window - have; 2062 } 2063 if (maxlen > avail) 2064 maxlen = avail; 2065 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2066 if (errno == EINTR || errno == EAGAIN) 2067 return 1; 2068 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2069 c->self, c->rfd, maxlen, ssh_err(r)); 2070 goto rfail; 2071 } 2072 if (nr != 0) 2073 c->lastused = monotime(); 2074 return 1; 2075 } 2076 2077 len = read(c->rfd, buf, sizeof(buf)); 2078 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2079 return 1; 2080 if (len <= 0) { 2081 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2082 c->self, c->rfd, len, 2083 len == 0 ? "closed" : strerror(errno)); 2084 rfail: 2085 if (c->type != SSH_CHANNEL_OPEN) { 2086 debug2("channel %d: not open", c->self); 2087 chan_mark_dead(ssh, c); 2088 return -1; 2089 } else { 2090 chan_read_failed(ssh, c); 2091 } 2092 return -1; 2093 } 2094 c->lastused = monotime(); 2095 if (c->input_filter != NULL) { 2096 if (c->input_filter(ssh, c, buf, len) == -1) { 2097 debug2("channel %d: filter stops", c->self); 2098 chan_read_failed(ssh, c); 2099 } 2100 } else if (c->datagram) { 2101 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2102 fatal_fr(r, "channel %i: put datagram", c->self); 2103 } 2104 return 1; 2105 } 2106 2107 static int 2108 channel_handle_wfd(struct ssh *ssh, Channel *c) 2109 { 2110 struct termios tio; 2111 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2112 size_t dlen, olen = 0; 2113 int r, len; 2114 2115 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2116 return 1; 2117 if (sshbuf_len(c->output) == 0) 2118 return 1; 2119 2120 /* Send buffered output data to the socket. */ 2121 olen = sshbuf_len(c->output); 2122 if (c->output_filter != NULL) { 2123 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2124 debug2("channel %d: filter stops", c->self); 2125 if (c->type != SSH_CHANNEL_OPEN) 2126 chan_mark_dead(ssh, c); 2127 else 2128 chan_write_failed(ssh, c); 2129 return -1; 2130 } 2131 } else if (c->datagram) { 2132 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2133 fatal_fr(r, "channel %i: get datagram", c->self); 2134 buf = data; 2135 } else { 2136 buf = data = sshbuf_mutable_ptr(c->output); 2137 dlen = sshbuf_len(c->output); 2138 } 2139 2140 if (c->datagram) { 2141 /* ignore truncated writes, datagrams might get lost */ 2142 len = write(c->wfd, buf, dlen); 2143 free(data); 2144 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2145 return 1; 2146 if (len <= 0) 2147 goto write_fail; 2148 goto out; 2149 } 2150 2151 len = write(c->wfd, buf, dlen); 2152 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2153 return 1; 2154 if (len <= 0) { 2155 write_fail: 2156 if (c->type != SSH_CHANNEL_OPEN) { 2157 debug2("channel %d: not open", c->self); 2158 chan_mark_dead(ssh, c); 2159 return -1; 2160 } else { 2161 chan_write_failed(ssh, c); 2162 } 2163 return -1; 2164 } 2165 c->lastused = monotime(); 2166 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2167 if (tcgetattr(c->wfd, &tio) == 0 && 2168 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2169 /* 2170 * Simulate echo to reduce the impact of 2171 * traffic analysis. We need to match the 2172 * size of a SSH2_MSG_CHANNEL_DATA message 2173 * (4 byte channel id + buf) 2174 */ 2175 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2176 (r = sshpkt_send(ssh)) != 0) 2177 fatal_fr(r, "channel %i: ignore", c->self); 2178 } 2179 } 2180 if ((r = sshbuf_consume(c->output, len)) != 0) 2181 fatal_fr(r, "channel %i: consume", c->self); 2182 out: 2183 c->local_consumed += olen - sshbuf_len(c->output); 2184 2185 return 1; 2186 } 2187 2188 static int 2189 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2190 { 2191 int r; 2192 ssize_t len; 2193 2194 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2195 return 1; 2196 if (sshbuf_len(c->extended) == 0) 2197 return 1; 2198 2199 len = write(c->efd, sshbuf_ptr(c->extended), 2200 sshbuf_len(c->extended)); 2201 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2202 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2203 return 1; 2204 if (len <= 0) { 2205 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2206 channel_close_fd(ssh, c, &c->efd); 2207 } else { 2208 if ((r = sshbuf_consume(c->extended, len)) != 0) 2209 fatal_fr(r, "channel %i: consume", c->self); 2210 c->local_consumed += len; 2211 c->lastused = monotime(); 2212 } 2213 return 1; 2214 } 2215 2216 static int 2217 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2218 { 2219 char buf[CHAN_RBUF]; 2220 int r; 2221 ssize_t len; 2222 2223 if ((c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2224 return 1; 2225 2226 len = read(c->efd, buf, sizeof(buf)); 2227 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2228 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2229 return 1; 2230 if (len <= 0) { 2231 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2232 channel_close_fd(ssh, c, &c->efd); 2233 return 1; 2234 } 2235 c->lastused = monotime(); 2236 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2237 debug3("channel %d: discard efd", c->self); 2238 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2239 fatal_fr(r, "channel %i: append", c->self); 2240 return 1; 2241 } 2242 2243 static int 2244 channel_handle_efd(struct ssh *ssh, Channel *c) 2245 { 2246 if (c->efd == -1) 2247 return 1; 2248 2249 /** XXX handle drain efd, too */ 2250 2251 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2252 return channel_handle_efd_write(ssh, c); 2253 else if (c->extended_usage == CHAN_EXTENDED_READ || 2254 c->extended_usage == CHAN_EXTENDED_IGNORE) 2255 return channel_handle_efd_read(ssh, c); 2256 2257 return 1; 2258 } 2259 2260 static int 2261 channel_check_window(struct ssh *ssh, Channel *c) 2262 { 2263 int r; 2264 2265 if (c->type == SSH_CHANNEL_OPEN && 2266 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2267 ((c->local_window_max - c->local_window > 2268 c->local_maxpacket*3) || 2269 c->local_window < c->local_window_max/2) && 2270 c->local_consumed > 0) { 2271 if (!c->have_remote_id) 2272 fatal_f("channel %d: no remote id", c->self); 2273 if ((r = sshpkt_start(ssh, 2274 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2275 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2276 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2277 (r = sshpkt_send(ssh)) != 0) { 2278 fatal_fr(r, "channel %i", c->self); 2279 } 2280 debug2("channel %d: window %d sent adjust %d", c->self, 2281 c->local_window, c->local_consumed); 2282 c->local_window += c->local_consumed; 2283 c->local_consumed = 0; 2284 } 2285 return 1; 2286 } 2287 2288 static void 2289 channel_post_open(struct ssh *ssh, Channel *c) 2290 { 2291 channel_handle_rfd(ssh, c); 2292 channel_handle_wfd(ssh, c); 2293 channel_handle_efd(ssh, c); 2294 channel_check_window(ssh, c); 2295 } 2296 2297 static u_int 2298 read_mux(struct ssh *ssh, Channel *c, u_int need) 2299 { 2300 char buf[CHAN_RBUF]; 2301 ssize_t len; 2302 u_int rlen; 2303 int r; 2304 2305 if (sshbuf_len(c->input) < need) { 2306 rlen = need - sshbuf_len(c->input); 2307 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2308 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2309 return sshbuf_len(c->input); 2310 if (len <= 0) { 2311 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2312 c->self, c->rfd, len); 2313 chan_read_failed(ssh, c); 2314 return 0; 2315 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2316 fatal_fr(r, "channel %i: append", c->self); 2317 } 2318 return sshbuf_len(c->input); 2319 } 2320 2321 static void 2322 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2323 { 2324 u_int need; 2325 2326 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2327 return; 2328 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2329 return; 2330 if (c->mux_pause) 2331 return; 2332 2333 /* 2334 * Don't not read past the precise end of packets to 2335 * avoid disrupting fd passing. 2336 */ 2337 if (read_mux(ssh, c, 4) < 4) /* read header */ 2338 return; 2339 /* XXX sshbuf_peek_u32 */ 2340 need = PEEK_U32(sshbuf_ptr(c->input)); 2341 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2342 if (need > CHANNEL_MUX_MAX_PACKET) { 2343 debug2("channel %d: packet too big %u > %u", 2344 c->self, CHANNEL_MUX_MAX_PACKET, need); 2345 chan_rcvd_oclose(ssh, c); 2346 return; 2347 } 2348 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2349 return; 2350 if (c->mux_rcb(ssh, c) != 0) { 2351 debug("channel %d: mux_rcb failed", c->self); 2352 chan_mark_dead(ssh, c); 2353 return; 2354 } 2355 } 2356 2357 static void 2358 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2359 { 2360 ssize_t len; 2361 int r; 2362 2363 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2364 return; 2365 if (sshbuf_len(c->output) == 0) 2366 return; 2367 2368 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2369 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2370 return; 2371 if (len <= 0) { 2372 chan_mark_dead(ssh, c); 2373 return; 2374 } 2375 if ((r = sshbuf_consume(c->output, len)) != 0) 2376 fatal_fr(r, "channel %i: consume", c->self); 2377 } 2378 2379 static void 2380 channel_post_mux_client(struct ssh *ssh, Channel *c) 2381 { 2382 channel_post_mux_client_read(ssh, c); 2383 channel_post_mux_client_write(ssh, c); 2384 } 2385 2386 static void 2387 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2388 { 2389 Channel *nc; 2390 struct sockaddr_storage addr; 2391 socklen_t addrlen; 2392 int newsock; 2393 uid_t euid; 2394 gid_t egid; 2395 2396 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2397 return; 2398 2399 debug("multiplexing control connection"); 2400 2401 /* 2402 * Accept connection on control socket 2403 */ 2404 memset(&addr, 0, sizeof(addr)); 2405 addrlen = sizeof(addr); 2406 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2407 &addrlen)) == -1) { 2408 error_f("accept: %s", strerror(errno)); 2409 if (errno == EMFILE || errno == ENFILE) 2410 c->notbefore = monotime() + 1; 2411 return; 2412 } 2413 2414 if (getpeereid(newsock, &euid, &egid) == -1) { 2415 error_f("getpeereid failed: %s", strerror(errno)); 2416 close(newsock); 2417 return; 2418 } 2419 if ((euid != 0) && (getuid() != euid)) { 2420 error("multiplex uid mismatch: peer euid %u != uid %u", 2421 (u_int)euid, (u_int)getuid()); 2422 close(newsock); 2423 return; 2424 } 2425 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2426 newsock, newsock, -1, c->local_window_max, 2427 c->local_maxpacket, 0, "mux-control", 1); 2428 nc->mux_rcb = c->mux_rcb; 2429 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2430 /* establish state */ 2431 nc->mux_rcb(ssh, nc); 2432 /* mux state transitions must not elicit protocol messages */ 2433 nc->flags |= CHAN_LOCAL; 2434 } 2435 2436 static void 2437 channel_handler_init(struct ssh_channels *sc) 2438 { 2439 chan_fn **pre, **post; 2440 2441 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2442 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2443 fatal_f("allocation failed"); 2444 2445 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2446 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2447 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2448 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2449 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2450 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2451 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2452 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2453 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2454 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2455 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2456 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2457 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2458 2459 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2460 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2461 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2462 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2463 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2464 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2465 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2466 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2467 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2468 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2469 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2470 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2471 2472 sc->channel_pre = pre; 2473 sc->channel_post = post; 2474 } 2475 2476 /* gc dead channels */ 2477 static void 2478 channel_garbage_collect(struct ssh *ssh, Channel *c) 2479 { 2480 if (c == NULL) 2481 return; 2482 if (c->detach_user != NULL) { 2483 if (!chan_is_dead(ssh, c, c->detach_close)) 2484 return; 2485 2486 debug2("channel %d: gc: notify user", c->self); 2487 c->detach_user(ssh, c->self, 0, NULL); 2488 /* if we still have a callback */ 2489 if (c->detach_user != NULL) 2490 return; 2491 debug2("channel %d: gc: user detached", c->self); 2492 } 2493 if (!chan_is_dead(ssh, c, 1)) 2494 return; 2495 debug2("channel %d: garbage collecting", c->self); 2496 channel_free(ssh, c); 2497 } 2498 2499 enum channel_table { CHAN_PRE, CHAN_POST }; 2500 2501 static void 2502 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2503 { 2504 struct ssh_channels *sc = ssh->chanctxt; 2505 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2506 u_int i, oalloc; 2507 Channel *c; 2508 time_t now; 2509 2510 now = monotime(); 2511 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2512 c = sc->channels[i]; 2513 if (c == NULL) 2514 continue; 2515 /* Try to keep IO going while rekeying */ 2516 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2517 continue; 2518 if (c->delayed) { 2519 if (table == CHAN_PRE) 2520 c->delayed = 0; 2521 else 2522 continue; 2523 } 2524 if (ftab[c->type] != NULL) { 2525 if (table == CHAN_PRE && 2526 c->type == SSH_CHANNEL_OPEN && 2527 c->inactive_deadline != 0 && c->lastused != 0 && 2528 now >= c->lastused + c->inactive_deadline) { 2529 /* channel closed for inactivity */ 2530 verbose("channel %d: closing after %u seconds " 2531 "of inactivity", c->self, 2532 c->inactive_deadline); 2533 channel_force_close(ssh, c, 1); 2534 } else if (c->notbefore <= now) { 2535 /* Run handlers that are not paused. */ 2536 (*ftab[c->type])(ssh, c); 2537 /* inactivity timeouts must interrupt poll() */ 2538 if (timeout != NULL && 2539 c->type == SSH_CHANNEL_OPEN && 2540 c->lastused != 0 && 2541 c->inactive_deadline != 0) { 2542 ptimeout_deadline_monotime(timeout, 2543 c->lastused + c->inactive_deadline); 2544 } 2545 } else if (timeout != NULL) { 2546 /* 2547 * Arrange for poll() wakeup when channel pause 2548 * timer expires. 2549 */ 2550 ptimeout_deadline_monotime(timeout, 2551 c->notbefore); 2552 } 2553 } 2554 channel_garbage_collect(ssh, c); 2555 } 2556 } 2557 2558 /* 2559 * Create sockets before preparing IO. 2560 * This is necessary for things that need to happen after reading 2561 * the network-input but need to be completed before IO event setup, e.g. 2562 * because they may create new channels. 2563 */ 2564 static void 2565 channel_before_prepare_io(struct ssh *ssh) 2566 { 2567 struct ssh_channels *sc = ssh->chanctxt; 2568 Channel *c; 2569 u_int i, oalloc; 2570 2571 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2572 c = sc->channels[i]; 2573 if (c == NULL) 2574 continue; 2575 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2576 channel_before_prepare_io_rdynamic(ssh, c); 2577 } 2578 } 2579 2580 static void 2581 dump_channel_poll(const char *func, const char *what, Channel *c, 2582 u_int pollfd_offset, struct pollfd *pfd) 2583 { 2584 #ifdef DEBUG_CHANNEL_POLL 2585 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2586 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2587 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2588 c->rfd, c->wfd, c->efd, c->sock, 2589 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2590 c->io_want, c->io_ready, 2591 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2592 #endif 2593 } 2594 2595 /* Prepare pollfd entries for a single channel */ 2596 static void 2597 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2598 struct pollfd *pfd, u_int npfd) 2599 { 2600 u_int ev, p = *next_pollfd; 2601 2602 if (c == NULL) 2603 return; 2604 if (p + 4 > npfd) { 2605 /* Shouldn't happen */ 2606 fatal_f("channel %d: bad pfd offset %u (max %u)", 2607 c->self, p, npfd); 2608 } 2609 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2610 /* 2611 * prepare c->rfd 2612 * 2613 * This is a special case, since c->rfd might be the same as 2614 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2615 * IO too. 2616 */ 2617 if (c->rfd != -1) { 2618 ev = 0; 2619 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2620 ev |= POLLIN; 2621 /* rfd == wfd */ 2622 if (c->wfd == c->rfd) { 2623 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2624 ev |= POLLOUT; 2625 } 2626 /* rfd == efd */ 2627 if (c->efd == c->rfd) { 2628 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2629 ev |= POLLIN; 2630 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2631 ev |= POLLOUT; 2632 } 2633 /* rfd == sock */ 2634 if (c->sock == c->rfd) { 2635 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2636 ev |= POLLIN; 2637 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2638 ev |= POLLOUT; 2639 } 2640 /* Pack a pfd entry if any event armed for this fd */ 2641 if (ev != 0) { 2642 c->pfds[0] = p; 2643 pfd[p].fd = c->rfd; 2644 pfd[p].events = ev; 2645 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2646 p++; 2647 } 2648 } 2649 /* prepare c->wfd if wanting IO and not already handled above */ 2650 if (c->wfd != -1 && c->rfd != c->wfd) { 2651 ev = 0; 2652 if ((c->io_want & SSH_CHAN_IO_WFD)) 2653 ev |= POLLOUT; 2654 /* Pack a pfd entry if any event armed for this fd */ 2655 if (ev != 0) { 2656 c->pfds[1] = p; 2657 pfd[p].fd = c->wfd; 2658 pfd[p].events = ev; 2659 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2660 p++; 2661 } 2662 } 2663 /* prepare c->efd if wanting IO and not already handled above */ 2664 if (c->efd != -1 && c->rfd != c->efd) { 2665 ev = 0; 2666 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2667 ev |= POLLIN; 2668 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2669 ev |= POLLOUT; 2670 /* Pack a pfd entry if any event armed for this fd */ 2671 if (ev != 0) { 2672 c->pfds[2] = p; 2673 pfd[p].fd = c->efd; 2674 pfd[p].events = ev; 2675 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2676 p++; 2677 } 2678 } 2679 /* prepare c->sock if wanting IO and not already handled above */ 2680 if (c->sock != -1 && c->rfd != c->sock) { 2681 ev = 0; 2682 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2683 ev |= POLLIN; 2684 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2685 ev |= POLLOUT; 2686 /* Pack a pfd entry if any event armed for this fd */ 2687 if (ev != 0) { 2688 c->pfds[3] = p; 2689 pfd[p].fd = c->sock; 2690 pfd[p].events = 0; 2691 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2692 p++; 2693 } 2694 } 2695 *next_pollfd = p; 2696 } 2697 2698 /* * Allocate/prepare poll structure */ 2699 void 2700 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2701 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2702 { 2703 struct ssh_channels *sc = ssh->chanctxt; 2704 u_int i, oalloc, p, npfd = npfd_reserved; 2705 2706 channel_before_prepare_io(ssh); /* might create a new channel */ 2707 /* clear out I/O flags from last poll */ 2708 for (i = 0; i < sc->channels_alloc; i++) { 2709 if (sc->channels[i] == NULL) 2710 continue; 2711 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2712 } 2713 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2714 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2715 fatal_f("too many channels"); /* shouldn't happen */ 2716 npfd += sc->channels_alloc * 4; 2717 if (npfd > *npfd_allocp) { 2718 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2719 npfd, sizeof(**pfdp)); 2720 *npfd_allocp = npfd; 2721 } 2722 *npfd_activep = npfd_reserved; 2723 oalloc = sc->channels_alloc; 2724 2725 channel_handler(ssh, CHAN_PRE, timeout); 2726 2727 if (oalloc != sc->channels_alloc) { 2728 /* shouldn't happen */ 2729 fatal_f("channels_alloc changed during CHAN_PRE " 2730 "(was %u, now %u)", oalloc, sc->channels_alloc); 2731 } 2732 2733 /* Prepare pollfd */ 2734 p = npfd_reserved; 2735 for (i = 0; i < sc->channels_alloc; i++) 2736 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2737 *npfd_activep = p; 2738 } 2739 2740 static void 2741 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2742 const char *what, u_int revents_mask, u_int ready) 2743 { 2744 struct pollfd *pfd = &pfds[p]; 2745 2746 if (fd == -1) 2747 return; 2748 if (p == -1 || (u_int)p >= npfd) 2749 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2750 dump_channel_poll(__func__, what, c, p, pfd); 2751 if (pfd->fd != fd) { 2752 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2753 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2754 c->rfd, c->wfd, c->efd, c->sock); 2755 } 2756 if ((pfd->revents & POLLNVAL) != 0) { 2757 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2758 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2759 } 2760 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2761 c->io_ready |= ready & c->io_want; 2762 } 2763 2764 /* 2765 * After poll, perform any appropriate operations for channels which have 2766 * events pending. 2767 */ 2768 void 2769 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2770 { 2771 struct ssh_channels *sc = ssh->chanctxt; 2772 u_int i; 2773 int p; 2774 Channel *c; 2775 2776 #ifdef DEBUG_CHANNEL_POLL 2777 for (p = 0; p < (int)npfd; p++) { 2778 if (pfd[p].revents == 0) 2779 continue; 2780 debug_f("pfd[%u].fd %d rev 0x%04x", 2781 p, pfd[p].fd, pfd[p].revents); 2782 } 2783 #endif 2784 2785 /* Convert pollfd into c->io_ready */ 2786 for (i = 0; i < sc->channels_alloc; i++) { 2787 c = sc->channels[i]; 2788 if (c == NULL) 2789 continue; 2790 /* if rfd is shared with efd/sock then wfd should be too */ 2791 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2792 (c->rfd == c->efd || c->rfd == c->sock)) { 2793 /* Shouldn't happen */ 2794 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2795 c->self, c->rfd, c->wfd, c->efd, c->sock); 2796 } 2797 c->io_ready = 0; 2798 /* rfd, potentially shared with wfd, efd and sock */ 2799 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2800 fd_ready(c, p, pfd, npfd, c->rfd, 2801 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2802 if (c->rfd == c->wfd) { 2803 fd_ready(c, p, pfd, npfd, c->wfd, 2804 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2805 } 2806 if (c->rfd == c->efd) { 2807 fd_ready(c, p, pfd, npfd, c->efd, 2808 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2809 fd_ready(c, p, pfd, npfd, c->efd, 2810 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2811 } 2812 if (c->rfd == c->sock) { 2813 fd_ready(c, p, pfd, npfd, c->sock, 2814 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2815 fd_ready(c, p, pfd, npfd, c->sock, 2816 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2817 } 2818 dump_channel_poll(__func__, "rfd", c, p, pfd); 2819 } 2820 /* wfd */ 2821 if (c->wfd != -1 && c->wfd != c->rfd && 2822 (p = c->pfds[1]) != -1) { 2823 fd_ready(c, p, pfd, npfd, c->wfd, 2824 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2825 dump_channel_poll(__func__, "wfd", c, p, pfd); 2826 } 2827 /* efd */ 2828 if (c->efd != -1 && c->efd != c->rfd && 2829 (p = c->pfds[2]) != -1) { 2830 fd_ready(c, p, pfd, npfd, c->efd, 2831 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2832 fd_ready(c, p, pfd, npfd, c->efd, 2833 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2834 dump_channel_poll(__func__, "efd", c, p, pfd); 2835 } 2836 /* sock */ 2837 if (c->sock != -1 && c->sock != c->rfd && 2838 (p = c->pfds[3]) != -1) { 2839 fd_ready(c, p, pfd, npfd, c->sock, 2840 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2841 fd_ready(c, p, pfd, npfd, c->sock, 2842 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2843 dump_channel_poll(__func__, "sock", c, p, pfd); 2844 } 2845 } 2846 channel_handler(ssh, CHAN_POST, NULL); 2847 } 2848 2849 /* 2850 * Enqueue data for channels with open or draining c->input. 2851 * Returns non-zero if a packet was enqueued. 2852 */ 2853 static int 2854 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2855 { 2856 size_t len, plen; 2857 const u_char *pkt; 2858 int r; 2859 2860 if ((len = sshbuf_len(c->input)) == 0) { 2861 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2862 /* 2863 * input-buffer is empty and read-socket shutdown: 2864 * tell peer, that we will not send more data: 2865 * send IEOF. 2866 * hack for extended data: delay EOF if EFD still 2867 * in use. 2868 */ 2869 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2870 debug2("channel %d: " 2871 "ibuf_empty delayed efd %d/(%zu)", 2872 c->self, c->efd, sshbuf_len(c->extended)); 2873 else 2874 chan_ibuf_empty(ssh, c); 2875 } 2876 return 0; 2877 } 2878 2879 if (!c->have_remote_id) 2880 fatal_f("channel %d: no remote id", c->self); 2881 2882 if (c->datagram) { 2883 /* Check datagram will fit; drop if not */ 2884 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2885 fatal_fr(r, "channel %i: get datagram", c->self); 2886 /* 2887 * XXX this does tail-drop on the datagram queue which is 2888 * usually suboptimal compared to head-drop. Better to have 2889 * backpressure at read time? (i.e. read + discard) 2890 */ 2891 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2892 debug("channel %d: datagram too big", c->self); 2893 return 0; 2894 } 2895 /* Enqueue it */ 2896 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2897 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2898 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2899 (r = sshpkt_send(ssh)) != 0) 2900 fatal_fr(r, "channel %i: send datagram", c->self); 2901 c->remote_window -= plen; 2902 return 1; 2903 } 2904 2905 /* Enqueue packet for buffered data. */ 2906 if (len > c->remote_window) 2907 len = c->remote_window; 2908 if (len > c->remote_maxpacket) 2909 len = c->remote_maxpacket; 2910 if (len == 0) 2911 return 0; 2912 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2913 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2914 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2915 (r = sshpkt_send(ssh)) != 0) 2916 fatal_fr(r, "channel %i: send data", c->self); 2917 if ((r = sshbuf_consume(c->input, len)) != 0) 2918 fatal_fr(r, "channel %i: consume", c->self); 2919 c->remote_window -= len; 2920 return 1; 2921 } 2922 2923 /* 2924 * Enqueue data for channels with open c->extended in read mode. 2925 * Returns non-zero if a packet was enqueued. 2926 */ 2927 static int 2928 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2929 { 2930 size_t len; 2931 int r; 2932 2933 if ((len = sshbuf_len(c->extended)) == 0) 2934 return 0; 2935 2936 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2937 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2938 if (len > c->remote_window) 2939 len = c->remote_window; 2940 if (len > c->remote_maxpacket) 2941 len = c->remote_maxpacket; 2942 if (len == 0) 2943 return 0; 2944 if (!c->have_remote_id) 2945 fatal_f("channel %d: no remote id", c->self); 2946 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2947 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2948 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2949 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2950 (r = sshpkt_send(ssh)) != 0) 2951 fatal_fr(r, "channel %i: data", c->self); 2952 if ((r = sshbuf_consume(c->extended, len)) != 0) 2953 fatal_fr(r, "channel %i: consume", c->self); 2954 c->remote_window -= len; 2955 debug2("channel %d: sent ext data %zu", c->self, len); 2956 return 1; 2957 } 2958 2959 /* 2960 * If there is data to send to the connection, enqueue some of it now. 2961 * Returns non-zero if data was enqueued. 2962 */ 2963 int 2964 channel_output_poll(struct ssh *ssh) 2965 { 2966 struct ssh_channels *sc = ssh->chanctxt; 2967 Channel *c; 2968 u_int i; 2969 int ret = 0; 2970 2971 for (i = 0; i < sc->channels_alloc; i++) { 2972 c = sc->channels[i]; 2973 if (c == NULL) 2974 continue; 2975 2976 /* 2977 * We are only interested in channels that can have buffered 2978 * incoming data. 2979 */ 2980 if (c->type != SSH_CHANNEL_OPEN) 2981 continue; 2982 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2983 /* XXX is this true? */ 2984 debug3("channel %d: will not send data after close", 2985 c->self); 2986 continue; 2987 } 2988 2989 /* Get the amount of buffered data for this channel. */ 2990 if (c->istate == CHAN_INPUT_OPEN || 2991 c->istate == CHAN_INPUT_WAIT_DRAIN) 2992 ret |= channel_output_poll_input_open(ssh, c); 2993 /* Send extended data, i.e. stderr */ 2994 if (!(c->flags & CHAN_EOF_SENT) && 2995 c->extended_usage == CHAN_EXTENDED_READ) 2996 ret |= channel_output_poll_extended_read(ssh, c); 2997 } 2998 return ret; 2999 } 3000 3001 /* -- mux proxy support */ 3002 3003 /* 3004 * When multiplexing channel messages for mux clients we have to deal 3005 * with downstream messages from the mux client and upstream messages 3006 * from the ssh server: 3007 * 1) Handling downstream messages is straightforward and happens 3008 * in channel_proxy_downstream(): 3009 * - We forward all messages (mostly) unmodified to the server. 3010 * - However, in order to route messages from upstream to the correct 3011 * downstream client, we have to replace the channel IDs used by the 3012 * mux clients with a unique channel ID because the mux clients might 3013 * use conflicting channel IDs. 3014 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3015 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3016 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3017 * with the newly allocated channel ID. 3018 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3019 * channels and processed by channel_proxy_upstream(). The local channel ID 3020 * is then translated back to the original mux client ID. 3021 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3022 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3023 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3024 * downstream mux client are removed. 3025 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3026 * requires more work, because they are not addressed to a specific 3027 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3028 * out whether the request is addressed to the local client or a 3029 * specific downstream client based on the listen-address/port. 3030 * 6) Agent and X11-Forwarding have a similar problem and are currently 3031 * not supported as the matching session/channel cannot be identified 3032 * easily. 3033 */ 3034 3035 /* 3036 * receive packets from downstream mux clients: 3037 * channel callback fired on read from mux client, creates 3038 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3039 * on channel creation. 3040 */ 3041 int 3042 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3043 { 3044 Channel *c = NULL; 3045 struct sshbuf *original = NULL, *modified = NULL; 3046 const u_char *cp; 3047 char *ctype = NULL, *listen_host = NULL; 3048 u_char type; 3049 size_t have; 3050 int ret = -1, r; 3051 u_int id, remote_id, listen_port; 3052 3053 /* sshbuf_dump(downstream->input, stderr); */ 3054 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3055 != 0) { 3056 error_fr(r, "parse"); 3057 return -1; 3058 } 3059 if (have < 2) { 3060 error_f("short message"); 3061 return -1; 3062 } 3063 type = cp[1]; 3064 /* skip padlen + type */ 3065 cp += 2; 3066 have -= 2; 3067 if (ssh_packet_log_type(type)) 3068 debug3_f("channel %u: down->up: type %u", 3069 downstream->self, type); 3070 3071 switch (type) { 3072 case SSH2_MSG_CHANNEL_OPEN: 3073 if ((original = sshbuf_from(cp, have)) == NULL || 3074 (modified = sshbuf_new()) == NULL) { 3075 error_f("alloc"); 3076 goto out; 3077 } 3078 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3079 (r = sshbuf_get_u32(original, &id)) != 0) { 3080 error_fr(r, "parse"); 3081 goto out; 3082 } 3083 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3084 -1, -1, -1, 0, 0, 0, ctype, 1); 3085 c->mux_ctx = downstream; /* point to mux client */ 3086 c->mux_downstream_id = id; /* original downstream id */ 3087 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3088 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3089 (r = sshbuf_putb(modified, original)) != 0) { 3090 error_fr(r, "compose"); 3091 channel_free(ssh, c); 3092 goto out; 3093 } 3094 break; 3095 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3096 /* 3097 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3098 * need to parse 'remote_id' instead of 'ctype'. 3099 */ 3100 if ((original = sshbuf_from(cp, have)) == NULL || 3101 (modified = sshbuf_new()) == NULL) { 3102 error_f("alloc"); 3103 goto out; 3104 } 3105 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3106 (r = sshbuf_get_u32(original, &id)) != 0) { 3107 error_fr(r, "parse"); 3108 goto out; 3109 } 3110 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3111 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3112 c->mux_ctx = downstream; /* point to mux client */ 3113 c->mux_downstream_id = id; 3114 c->remote_id = remote_id; 3115 c->have_remote_id = 1; 3116 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3117 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3118 (r = sshbuf_putb(modified, original)) != 0) { 3119 error_fr(r, "compose"); 3120 channel_free(ssh, c); 3121 goto out; 3122 } 3123 break; 3124 case SSH2_MSG_GLOBAL_REQUEST: 3125 if ((original = sshbuf_from(cp, have)) == NULL) { 3126 error_f("alloc"); 3127 goto out; 3128 } 3129 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3130 error_fr(r, "parse"); 3131 goto out; 3132 } 3133 if (strcmp(ctype, "tcpip-forward") != 0) { 3134 error_f("unsupported request %s", ctype); 3135 goto out; 3136 } 3137 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3138 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3139 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3140 error_fr(r, "parse"); 3141 goto out; 3142 } 3143 if (listen_port > 65535) { 3144 error_f("tcpip-forward for %s: bad port %u", 3145 listen_host, listen_port); 3146 goto out; 3147 } 3148 /* Record that connection to this host/port is permitted. */ 3149 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 3150 listen_host, NULL, (int)listen_port, downstream); 3151 listen_host = NULL; 3152 break; 3153 case SSH2_MSG_CHANNEL_CLOSE: 3154 if (have < 4) 3155 break; 3156 remote_id = PEEK_U32(cp); 3157 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3158 if (c->flags & CHAN_CLOSE_RCVD) 3159 channel_free(ssh, c); 3160 else 3161 c->flags |= CHAN_CLOSE_SENT; 3162 } 3163 break; 3164 } 3165 if (modified) { 3166 if ((r = sshpkt_start(ssh, type)) != 0 || 3167 (r = sshpkt_putb(ssh, modified)) != 0 || 3168 (r = sshpkt_send(ssh)) != 0) { 3169 error_fr(r, "send"); 3170 goto out; 3171 } 3172 } else { 3173 if ((r = sshpkt_start(ssh, type)) != 0 || 3174 (r = sshpkt_put(ssh, cp, have)) != 0 || 3175 (r = sshpkt_send(ssh)) != 0) { 3176 error_fr(r, "send"); 3177 goto out; 3178 } 3179 } 3180 ret = 0; 3181 out: 3182 free(ctype); 3183 free(listen_host); 3184 sshbuf_free(original); 3185 sshbuf_free(modified); 3186 return ret; 3187 } 3188 3189 /* 3190 * receive packets from upstream server and de-multiplex packets 3191 * to correct downstream: 3192 * implemented as a helper for channel input handlers, 3193 * replaces local (proxy) channel ID with downstream channel ID. 3194 */ 3195 int 3196 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3197 { 3198 struct sshbuf *b = NULL; 3199 Channel *downstream; 3200 const u_char *cp = NULL; 3201 size_t len; 3202 int r; 3203 3204 /* 3205 * When receiving packets from the peer we need to check whether we 3206 * need to forward the packets to the mux client. In this case we 3207 * restore the original channel id and keep track of CLOSE messages, 3208 * so we can cleanup the channel. 3209 */ 3210 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3211 return 0; 3212 if ((downstream = c->mux_ctx) == NULL) 3213 return 0; 3214 switch (type) { 3215 case SSH2_MSG_CHANNEL_CLOSE: 3216 case SSH2_MSG_CHANNEL_DATA: 3217 case SSH2_MSG_CHANNEL_EOF: 3218 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3219 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3220 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3221 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3222 case SSH2_MSG_CHANNEL_SUCCESS: 3223 case SSH2_MSG_CHANNEL_FAILURE: 3224 case SSH2_MSG_CHANNEL_REQUEST: 3225 break; 3226 default: 3227 debug2_f("channel %u: unsupported type %u", c->self, type); 3228 return 0; 3229 } 3230 if ((b = sshbuf_new()) == NULL) { 3231 error_f("alloc reply"); 3232 goto out; 3233 } 3234 /* get remaining payload (after id) */ 3235 cp = sshpkt_ptr(ssh, &len); 3236 if (cp == NULL) { 3237 error_f("no packet"); 3238 goto out; 3239 } 3240 /* translate id and send to muxclient */ 3241 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3242 (r = sshbuf_put_u8(b, type)) != 0 || 3243 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3244 (r = sshbuf_put(b, cp, len)) != 0 || 3245 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3246 error_fr(r, "compose muxclient"); 3247 goto out; 3248 } 3249 /* sshbuf_dump(b, stderr); */ 3250 if (ssh_packet_log_type(type)) 3251 debug3_f("channel %u: up->down: type %u", c->self, type); 3252 out: 3253 /* update state */ 3254 switch (type) { 3255 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3256 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3257 if (cp && len > 4) { 3258 c->remote_id = PEEK_U32(cp); 3259 c->have_remote_id = 1; 3260 } 3261 break; 3262 case SSH2_MSG_CHANNEL_CLOSE: 3263 if (c->flags & CHAN_CLOSE_SENT) 3264 channel_free(ssh, c); 3265 else 3266 c->flags |= CHAN_CLOSE_RCVD; 3267 break; 3268 } 3269 sshbuf_free(b); 3270 return 1; 3271 } 3272 3273 /* -- protocol input */ 3274 3275 /* Parse a channel ID from the current packet */ 3276 static int 3277 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3278 { 3279 u_int32_t id; 3280 int r; 3281 3282 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3283 error_r(r, "%s: parse id", where); 3284 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3285 } 3286 if (id > INT_MAX) { 3287 error_r(r, "%s: bad channel id %u", where, id); 3288 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3289 } 3290 return (int)id; 3291 } 3292 3293 /* Lookup a channel from an ID in the current packet */ 3294 static Channel * 3295 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3296 { 3297 int id = channel_parse_id(ssh, where, what); 3298 Channel *c; 3299 3300 if ((c = channel_lookup(ssh, id)) == NULL) { 3301 ssh_packet_disconnect(ssh, 3302 "%s packet referred to nonexistent channel %d", what, id); 3303 } 3304 return c; 3305 } 3306 3307 int 3308 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3309 { 3310 const u_char *data; 3311 size_t data_len, win_len; 3312 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3313 int r; 3314 3315 if (channel_proxy_upstream(c, type, seq, ssh)) 3316 return 0; 3317 3318 /* Ignore any data for non-open channels (might happen on close) */ 3319 if (c->type != SSH_CHANNEL_OPEN && 3320 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3321 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3322 c->type != SSH_CHANNEL_X11_OPEN) 3323 return 0; 3324 3325 /* Get the data. */ 3326 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3327 (r = sshpkt_get_end(ssh)) != 0) 3328 fatal_fr(r, "channel %i: get data", c->self); 3329 3330 win_len = data_len; 3331 if (c->datagram) 3332 win_len += 4; /* string length header */ 3333 3334 /* 3335 * The sending side reduces its window as it sends data, so we 3336 * must 'fake' consumption of the data in order to ensure that window 3337 * updates are sent back. Otherwise the connection might deadlock. 3338 */ 3339 if (c->ostate != CHAN_OUTPUT_OPEN) { 3340 c->local_window -= win_len; 3341 c->local_consumed += win_len; 3342 return 0; 3343 } 3344 3345 if (win_len > c->local_maxpacket) { 3346 logit("channel %d: rcvd big packet %zu, maxpack %u", 3347 c->self, win_len, c->local_maxpacket); 3348 return 0; 3349 } 3350 if (win_len > c->local_window) { 3351 logit("channel %d: rcvd too much data %zu, win %u", 3352 c->self, win_len, c->local_window); 3353 return 0; 3354 } 3355 c->local_window -= win_len; 3356 3357 if (c->datagram) { 3358 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3359 fatal_fr(r, "channel %i: append datagram", c->self); 3360 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3361 fatal_fr(r, "channel %i: append data", c->self); 3362 3363 return 0; 3364 } 3365 3366 int 3367 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3368 { 3369 const u_char *data; 3370 size_t data_len; 3371 u_int32_t tcode; 3372 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3373 int r; 3374 3375 if (channel_proxy_upstream(c, type, seq, ssh)) 3376 return 0; 3377 if (c->type != SSH_CHANNEL_OPEN) { 3378 logit("channel %d: ext data for non open", c->self); 3379 return 0; 3380 } 3381 if (c->flags & CHAN_EOF_RCVD) { 3382 if (ssh->compat & SSH_BUG_EXTEOF) 3383 debug("channel %d: accepting ext data after eof", 3384 c->self); 3385 else 3386 ssh_packet_disconnect(ssh, "Received extended_data " 3387 "after EOF on channel %d.", c->self); 3388 } 3389 3390 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3391 error_fr(r, "parse tcode"); 3392 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3393 } 3394 if (c->efd == -1 || 3395 c->extended_usage != CHAN_EXTENDED_WRITE || 3396 tcode != SSH2_EXTENDED_DATA_STDERR) { 3397 logit("channel %d: bad ext data", c->self); 3398 return 0; 3399 } 3400 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3401 (r = sshpkt_get_end(ssh)) != 0) { 3402 error_fr(r, "parse data"); 3403 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3404 } 3405 3406 if (data_len > c->local_window) { 3407 logit("channel %d: rcvd too much extended_data %zu, win %u", 3408 c->self, data_len, c->local_window); 3409 return 0; 3410 } 3411 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3412 /* XXX sshpkt_getb? */ 3413 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3414 error_fr(r, "append"); 3415 c->local_window -= data_len; 3416 return 0; 3417 } 3418 3419 int 3420 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3421 { 3422 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3423 int r; 3424 3425 if ((r = sshpkt_get_end(ssh)) != 0) { 3426 error_fr(r, "parse data"); 3427 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3428 } 3429 3430 if (channel_proxy_upstream(c, type, seq, ssh)) 3431 return 0; 3432 chan_rcvd_ieof(ssh, c); 3433 3434 /* XXX force input close */ 3435 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3436 debug("channel %d: FORCE input drain", c->self); 3437 c->istate = CHAN_INPUT_WAIT_DRAIN; 3438 if (sshbuf_len(c->input) == 0) 3439 chan_ibuf_empty(ssh, c); 3440 } 3441 return 0; 3442 } 3443 3444 int 3445 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3446 { 3447 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3448 int r; 3449 3450 if (channel_proxy_upstream(c, type, seq, ssh)) 3451 return 0; 3452 if ((r = sshpkt_get_end(ssh)) != 0) { 3453 error_fr(r, "parse data"); 3454 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3455 } 3456 chan_rcvd_oclose(ssh, c); 3457 return 0; 3458 } 3459 3460 int 3461 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3462 { 3463 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3464 u_int32_t remote_window, remote_maxpacket; 3465 int r; 3466 3467 if (channel_proxy_upstream(c, type, seq, ssh)) 3468 return 0; 3469 if (c->type != SSH_CHANNEL_OPENING) 3470 ssh_packet_disconnect(ssh, "Received open confirmation for " 3471 "non-opening channel %d.", c->self); 3472 /* 3473 * Record the remote channel number and mark that the channel 3474 * is now open. 3475 */ 3476 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3477 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3478 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3479 (r = sshpkt_get_end(ssh)) != 0) { 3480 error_fr(r, "window/maxpacket"); 3481 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3482 } 3483 3484 c->have_remote_id = 1; 3485 c->remote_window = remote_window; 3486 c->remote_maxpacket = remote_maxpacket; 3487 c->type = SSH_CHANNEL_OPEN; 3488 if (c->open_confirm) { 3489 debug2_f("channel %d: callback start", c->self); 3490 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3491 debug2_f("channel %d: callback done", c->self); 3492 } 3493 c->lastused = monotime(); 3494 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3495 c->remote_window, c->remote_maxpacket); 3496 return 0; 3497 } 3498 3499 static char * 3500 reason2txt(int reason) 3501 { 3502 switch (reason) { 3503 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3504 return "administratively prohibited"; 3505 case SSH2_OPEN_CONNECT_FAILED: 3506 return "connect failed"; 3507 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3508 return "unknown channel type"; 3509 case SSH2_OPEN_RESOURCE_SHORTAGE: 3510 return "resource shortage"; 3511 } 3512 return "unknown reason"; 3513 } 3514 3515 int 3516 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3517 { 3518 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3519 u_int32_t reason; 3520 char *msg = NULL; 3521 int r; 3522 3523 if (channel_proxy_upstream(c, type, seq, ssh)) 3524 return 0; 3525 if (c->type != SSH_CHANNEL_OPENING) 3526 ssh_packet_disconnect(ssh, "Received open failure for " 3527 "non-opening channel %d.", c->self); 3528 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3529 error_fr(r, "parse reason"); 3530 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3531 } 3532 /* skip language */ 3533 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3534 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3535 (r = sshpkt_get_end(ssh)) != 0) { 3536 error_fr(r, "parse msg/lang"); 3537 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3538 } 3539 logit("channel %d: open failed: %s%s%s", c->self, 3540 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3541 free(msg); 3542 if (c->open_confirm) { 3543 debug2_f("channel %d: callback start", c->self); 3544 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3545 debug2_f("channel %d: callback done", c->self); 3546 } 3547 /* Schedule the channel for cleanup/deletion. */ 3548 chan_mark_dead(ssh, c); 3549 return 0; 3550 } 3551 3552 int 3553 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3554 { 3555 int id = channel_parse_id(ssh, __func__, "window adjust"); 3556 Channel *c; 3557 u_int32_t adjust; 3558 u_int new_rwin; 3559 int r; 3560 3561 if ((c = channel_lookup(ssh, id)) == NULL) { 3562 logit("Received window adjust for non-open channel %d.", id); 3563 return 0; 3564 } 3565 3566 if (channel_proxy_upstream(c, type, seq, ssh)) 3567 return 0; 3568 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3569 (r = sshpkt_get_end(ssh)) != 0) { 3570 error_fr(r, "parse adjust"); 3571 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3572 } 3573 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3574 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3575 fatal("channel %d: adjust %u overflows remote window %u", 3576 c->self, adjust, c->remote_window); 3577 } 3578 c->remote_window = new_rwin; 3579 return 0; 3580 } 3581 3582 int 3583 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3584 { 3585 int id = channel_parse_id(ssh, __func__, "status confirm"); 3586 Channel *c; 3587 struct channel_confirm *cc; 3588 3589 /* Reset keepalive timeout */ 3590 ssh_packet_set_alive_timeouts(ssh, 0); 3591 3592 debug2_f("type %d id %d", type, id); 3593 3594 if ((c = channel_lookup(ssh, id)) == NULL) { 3595 logit_f("%d: unknown", id); 3596 return 0; 3597 } 3598 if (channel_proxy_upstream(c, type, seq, ssh)) 3599 return 0; 3600 if (sshpkt_get_end(ssh) != 0) 3601 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3602 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3603 return 0; 3604 cc->cb(ssh, type, c, cc->ctx); 3605 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3606 freezero(cc, sizeof(*cc)); 3607 return 0; 3608 } 3609 3610 /* -- tcp forwarding */ 3611 3612 void 3613 channel_set_af(struct ssh *ssh, int af) 3614 { 3615 ssh->chanctxt->IPv4or6 = af; 3616 } 3617 3618 3619 /* 3620 * Determine whether or not a port forward listens to loopback, the 3621 * specified address or wildcard. On the client, a specified bind 3622 * address will always override gateway_ports. On the server, a 3623 * gateway_ports of 1 (``yes'') will override the client's specification 3624 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3625 * will bind to whatever address the client asked for. 3626 * 3627 * Special-case listen_addrs are: 3628 * 3629 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3630 * "" (empty string), "*" -> wildcard v4/v6 3631 * "localhost" -> loopback v4/v6 3632 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3633 */ 3634 static const char * 3635 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3636 int is_client, struct ForwardOptions *fwd_opts) 3637 { 3638 const char *addr = NULL; 3639 int wildcard = 0; 3640 3641 if (listen_addr == NULL) { 3642 /* No address specified: default to gateway_ports setting */ 3643 if (fwd_opts->gateway_ports) 3644 wildcard = 1; 3645 } else if (fwd_opts->gateway_ports || is_client) { 3646 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3647 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3648 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3649 (!is_client && fwd_opts->gateway_ports == 1)) { 3650 wildcard = 1; 3651 /* 3652 * Notify client if they requested a specific listen 3653 * address and it was overridden. 3654 */ 3655 if (*listen_addr != '\0' && 3656 strcmp(listen_addr, "0.0.0.0") != 0 && 3657 strcmp(listen_addr, "*") != 0) { 3658 ssh_packet_send_debug(ssh, 3659 "Forwarding listen address " 3660 "\"%s\" overridden by server " 3661 "GatewayPorts", listen_addr); 3662 } 3663 } else if (strcmp(listen_addr, "localhost") != 0 || 3664 strcmp(listen_addr, "127.0.0.1") == 0 || 3665 strcmp(listen_addr, "::1") == 0) { 3666 /* 3667 * Accept explicit localhost address when 3668 * GatewayPorts=yes. The "localhost" hostname is 3669 * deliberately skipped here so it will listen on all 3670 * available local address families. 3671 */ 3672 addr = listen_addr; 3673 } 3674 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3675 strcmp(listen_addr, "::1") == 0) { 3676 /* 3677 * If a specific IPv4/IPv6 localhost address has been 3678 * requested then accept it even if gateway_ports is in 3679 * effect. This allows the client to prefer IPv4 or IPv6. 3680 */ 3681 addr = listen_addr; 3682 } 3683 if (wildcardp != NULL) 3684 *wildcardp = wildcard; 3685 return addr; 3686 } 3687 3688 static int 3689 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3690 struct Forward *fwd, int *allocated_listen_port, 3691 struct ForwardOptions *fwd_opts) 3692 { 3693 Channel *c; 3694 int sock, r, success = 0, wildcard = 0, is_client; 3695 struct addrinfo hints, *ai, *aitop; 3696 const char *host, *addr; 3697 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3698 in_port_t *lport_p; 3699 3700 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3701 3702 if (is_client && fwd->connect_path != NULL) { 3703 host = fwd->connect_path; 3704 } else { 3705 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3706 fwd->listen_host : fwd->connect_host; 3707 if (host == NULL) { 3708 error("No forward host name."); 3709 return 0; 3710 } 3711 if (strlen(host) >= NI_MAXHOST) { 3712 error("Forward host name too long."); 3713 return 0; 3714 } 3715 } 3716 3717 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3718 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3719 is_client, fwd_opts); 3720 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3721 (addr == NULL) ? "NULL" : addr); 3722 3723 /* 3724 * getaddrinfo returns a loopback address if the hostname is 3725 * set to NULL and hints.ai_flags is not AI_PASSIVE 3726 */ 3727 memset(&hints, 0, sizeof(hints)); 3728 hints.ai_family = ssh->chanctxt->IPv4or6; 3729 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3730 hints.ai_socktype = SOCK_STREAM; 3731 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3732 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3733 if (addr == NULL) { 3734 /* This really shouldn't happen */ 3735 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3736 ssh_gai_strerror(r)); 3737 } else { 3738 error_f("getaddrinfo(%.64s): %s", addr, 3739 ssh_gai_strerror(r)); 3740 } 3741 return 0; 3742 } 3743 if (allocated_listen_port != NULL) 3744 *allocated_listen_port = 0; 3745 for (ai = aitop; ai; ai = ai->ai_next) { 3746 switch (ai->ai_family) { 3747 case AF_INET: 3748 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3749 sin_port; 3750 break; 3751 case AF_INET6: 3752 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3753 sin6_port; 3754 break; 3755 default: 3756 continue; 3757 } 3758 /* 3759 * If allocating a port for -R forwards, then use the 3760 * same port for all address families. 3761 */ 3762 if (type == SSH_CHANNEL_RPORT_LISTENER && 3763 fwd->listen_port == 0 && allocated_listen_port != NULL && 3764 *allocated_listen_port > 0) 3765 *lport_p = htons(*allocated_listen_port); 3766 3767 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3768 strport, sizeof(strport), 3769 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3770 error_f("getnameinfo failed"); 3771 continue; 3772 } 3773 /* Create a port to listen for the host. */ 3774 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3775 if (sock == -1) { 3776 /* this is no error since kernel may not support ipv6 */ 3777 verbose("socket [%s]:%s: %.100s", ntop, strport, 3778 strerror(errno)); 3779 continue; 3780 } 3781 3782 set_reuseaddr(sock); 3783 3784 debug("Local forwarding listening on %s port %s.", 3785 ntop, strport); 3786 3787 /* Bind the socket to the address. */ 3788 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3789 /* 3790 * address can be in if use ipv6 address is 3791 * already bound 3792 */ 3793 verbose("bind [%s]:%s: %.100s", 3794 ntop, strport, strerror(errno)); 3795 close(sock); 3796 continue; 3797 } 3798 /* Start listening for connections on the socket. */ 3799 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3800 error("listen [%s]:%s: %.100s", ntop, strport, 3801 strerror(errno)); 3802 close(sock); 3803 continue; 3804 } 3805 3806 /* 3807 * fwd->listen_port == 0 requests a dynamically allocated port - 3808 * record what we got. 3809 */ 3810 if (type == SSH_CHANNEL_RPORT_LISTENER && 3811 fwd->listen_port == 0 && 3812 allocated_listen_port != NULL && 3813 *allocated_listen_port == 0) { 3814 *allocated_listen_port = get_local_port(sock); 3815 debug("Allocated listen port %d", 3816 *allocated_listen_port); 3817 } 3818 3819 /* Allocate a channel number for the socket. */ 3820 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3821 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3822 0, "port listener", 1); 3823 c->path = xstrdup(host); 3824 c->host_port = fwd->connect_port; 3825 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3826 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3827 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3828 c->listening_port = *allocated_listen_port; 3829 else 3830 c->listening_port = fwd->listen_port; 3831 success = 1; 3832 } 3833 if (success == 0) 3834 error_f("cannot listen to port: %d", fwd->listen_port); 3835 freeaddrinfo(aitop); 3836 return success; 3837 } 3838 3839 static int 3840 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3841 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3842 { 3843 struct sockaddr_un sunaddr; 3844 const char *path; 3845 Channel *c; 3846 int port, sock; 3847 mode_t omask; 3848 3849 switch (type) { 3850 case SSH_CHANNEL_UNIX_LISTENER: 3851 if (fwd->connect_path != NULL) { 3852 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3853 error("Local connecting path too long: %s", 3854 fwd->connect_path); 3855 return 0; 3856 } 3857 path = fwd->connect_path; 3858 port = PORT_STREAMLOCAL; 3859 } else { 3860 if (fwd->connect_host == NULL) { 3861 error("No forward host name."); 3862 return 0; 3863 } 3864 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3865 error("Forward host name too long."); 3866 return 0; 3867 } 3868 path = fwd->connect_host; 3869 port = fwd->connect_port; 3870 } 3871 break; 3872 case SSH_CHANNEL_RUNIX_LISTENER: 3873 path = fwd->listen_path; 3874 port = PORT_STREAMLOCAL; 3875 break; 3876 default: 3877 error_f("unexpected channel type %d", type); 3878 return 0; 3879 } 3880 3881 if (fwd->listen_path == NULL) { 3882 error("No forward path name."); 3883 return 0; 3884 } 3885 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3886 error("Local listening path too long: %s", fwd->listen_path); 3887 return 0; 3888 } 3889 3890 debug3_f("type %d path %s", type, fwd->listen_path); 3891 3892 /* Start a Unix domain listener. */ 3893 omask = umask(fwd_opts->streamlocal_bind_mask); 3894 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3895 fwd_opts->streamlocal_bind_unlink); 3896 umask(omask); 3897 if (sock < 0) 3898 return 0; 3899 3900 debug("Local forwarding listening on path %s.", fwd->listen_path); 3901 3902 /* Allocate a channel number for the socket. */ 3903 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 3904 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3905 0, "unix listener", 1); 3906 c->path = xstrdup(path); 3907 c->host_port = port; 3908 c->listening_port = PORT_STREAMLOCAL; 3909 c->listening_addr = xstrdup(fwd->listen_path); 3910 return 1; 3911 } 3912 3913 static int 3914 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3915 const char *host, u_short port) 3916 { 3917 u_int i; 3918 int found = 0; 3919 3920 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3921 Channel *c = ssh->chanctxt->channels[i]; 3922 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3923 continue; 3924 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3925 debug2_f("close channel %d", i); 3926 channel_free(ssh, c); 3927 found = 1; 3928 } 3929 } 3930 3931 return found; 3932 } 3933 3934 static int 3935 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3936 { 3937 u_int i; 3938 int found = 0; 3939 3940 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3941 Channel *c = ssh->chanctxt->channels[i]; 3942 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3943 continue; 3944 if (c->path == NULL) 3945 continue; 3946 if (strcmp(c->path, path) == 0) { 3947 debug2_f("close channel %d", i); 3948 channel_free(ssh, c); 3949 found = 1; 3950 } 3951 } 3952 3953 return found; 3954 } 3955 3956 int 3957 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3958 { 3959 if (fwd->listen_path != NULL) { 3960 return channel_cancel_rport_listener_streamlocal(ssh, 3961 fwd->listen_path); 3962 } else { 3963 return channel_cancel_rport_listener_tcpip(ssh, 3964 fwd->listen_host, fwd->listen_port); 3965 } 3966 } 3967 3968 static int 3969 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 3970 const char *lhost, u_short lport, int cport, 3971 struct ForwardOptions *fwd_opts) 3972 { 3973 u_int i; 3974 int found = 0; 3975 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 3976 3977 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3978 Channel *c = ssh->chanctxt->channels[i]; 3979 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 3980 continue; 3981 if (c->listening_port != lport) 3982 continue; 3983 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 3984 /* skip dynamic forwardings */ 3985 if (c->host_port == 0) 3986 continue; 3987 } else { 3988 if (c->host_port != cport) 3989 continue; 3990 } 3991 if ((c->listening_addr == NULL && addr != NULL) || 3992 (c->listening_addr != NULL && addr == NULL)) 3993 continue; 3994 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 3995 debug2_f("close channel %d", i); 3996 channel_free(ssh, c); 3997 found = 1; 3998 } 3999 } 4000 4001 return found; 4002 } 4003 4004 static int 4005 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4006 { 4007 u_int i; 4008 int found = 0; 4009 4010 if (path == NULL) { 4011 error_f("no path specified."); 4012 return 0; 4013 } 4014 4015 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4016 Channel *c = ssh->chanctxt->channels[i]; 4017 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4018 continue; 4019 if (c->listening_addr == NULL) 4020 continue; 4021 if (strcmp(c->listening_addr, path) == 0) { 4022 debug2_f("close channel %d", i); 4023 channel_free(ssh, c); 4024 found = 1; 4025 } 4026 } 4027 4028 return found; 4029 } 4030 4031 int 4032 channel_cancel_lport_listener(struct ssh *ssh, 4033 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4034 { 4035 if (fwd->listen_path != NULL) { 4036 return channel_cancel_lport_listener_streamlocal(ssh, 4037 fwd->listen_path); 4038 } else { 4039 return channel_cancel_lport_listener_tcpip(ssh, 4040 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4041 } 4042 } 4043 4044 /* protocol local port fwd, used by ssh */ 4045 int 4046 channel_setup_local_fwd_listener(struct ssh *ssh, 4047 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4048 { 4049 if (fwd->listen_path != NULL) { 4050 return channel_setup_fwd_listener_streamlocal(ssh, 4051 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4052 } else { 4053 return channel_setup_fwd_listener_tcpip(ssh, 4054 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4055 } 4056 } 4057 4058 /* Matches a remote forwarding permission against a requested forwarding */ 4059 static int 4060 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4061 { 4062 int ret; 4063 char *lhost; 4064 4065 /* XXX add ACLs for streamlocal */ 4066 if (fwd->listen_path != NULL) 4067 return 1; 4068 4069 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4070 return 0; 4071 4072 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4073 allowed_open->listen_port != fwd->listen_port) 4074 return 0; 4075 4076 /* Match hostnames case-insensitively */ 4077 lhost = xstrdup(fwd->listen_host); 4078 lowercase(lhost); 4079 ret = match_pattern(lhost, allowed_open->listen_host); 4080 free(lhost); 4081 4082 return ret; 4083 } 4084 4085 /* Checks whether a requested remote forwarding is permitted */ 4086 static int 4087 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4088 { 4089 struct ssh_channels *sc = ssh->chanctxt; 4090 struct permission_set *pset = &sc->remote_perms; 4091 u_int i, permit, permit_adm = 1; 4092 struct permission *perm; 4093 4094 /* XXX apply GatewayPorts override before checking? */ 4095 4096 permit = pset->all_permitted; 4097 if (!permit) { 4098 for (i = 0; i < pset->num_permitted_user; i++) { 4099 perm = &pset->permitted_user[i]; 4100 if (remote_open_match(perm, fwd)) { 4101 permit = 1; 4102 break; 4103 } 4104 } 4105 } 4106 4107 if (pset->num_permitted_admin > 0) { 4108 permit_adm = 0; 4109 for (i = 0; i < pset->num_permitted_admin; i++) { 4110 perm = &pset->permitted_admin[i]; 4111 if (remote_open_match(perm, fwd)) { 4112 permit_adm = 1; 4113 break; 4114 } 4115 } 4116 } 4117 4118 return permit && permit_adm; 4119 } 4120 4121 /* protocol v2 remote port fwd, used by sshd */ 4122 int 4123 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4124 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4125 { 4126 if (!check_rfwd_permission(ssh, fwd)) { 4127 ssh_packet_send_debug(ssh, "port forwarding refused"); 4128 if (fwd->listen_path != NULL) 4129 /* XXX always allowed, see remote_open_match() */ 4130 logit("Received request from %.100s port %d to " 4131 "remote forward to path \"%.100s\", " 4132 "but the request was denied.", 4133 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4134 fwd->listen_path); 4135 else if(fwd->listen_host != NULL) 4136 logit("Received request from %.100s port %d to " 4137 "remote forward to host %.100s port %d, " 4138 "but the request was denied.", 4139 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4140 fwd->listen_host, fwd->listen_port ); 4141 else 4142 logit("Received request from %.100s port %d to remote " 4143 "forward, but the request was denied.", 4144 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4145 return 0; 4146 } 4147 if (fwd->listen_path != NULL) { 4148 return channel_setup_fwd_listener_streamlocal(ssh, 4149 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4150 } else { 4151 return channel_setup_fwd_listener_tcpip(ssh, 4152 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4153 fwd_opts); 4154 } 4155 } 4156 4157 /* 4158 * Translate the requested rfwd listen host to something usable for 4159 * this server. 4160 */ 4161 static const char * 4162 channel_rfwd_bind_host(const char *listen_host) 4163 { 4164 if (listen_host == NULL) { 4165 return "localhost"; 4166 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4167 return ""; 4168 } else 4169 return listen_host; 4170 } 4171 4172 /* 4173 * Initiate forwarding of connections to port "port" on remote host through 4174 * the secure channel to host:port from local side. 4175 * Returns handle (index) for updating the dynamic listen port with 4176 * channel_update_permission(). 4177 */ 4178 int 4179 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4180 { 4181 int r, success = 0, idx = -1; 4182 const char *host_to_connect, *listen_host, *listen_path; 4183 int port_to_connect, listen_port; 4184 4185 /* Send the forward request to the remote side. */ 4186 if (fwd->listen_path != NULL) { 4187 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4188 (r = sshpkt_put_cstring(ssh, 4189 "streamlocal-forward@openssh.com")) != 0 || 4190 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4191 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4192 (r = sshpkt_send(ssh)) != 0 || 4193 (r = ssh_packet_write_wait(ssh)) != 0) 4194 fatal_fr(r, "request streamlocal"); 4195 } else { 4196 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4197 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4198 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4199 (r = sshpkt_put_cstring(ssh, 4200 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4201 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4202 (r = sshpkt_send(ssh)) != 0 || 4203 (r = ssh_packet_write_wait(ssh)) != 0) 4204 fatal_fr(r, "request tcpip-forward"); 4205 } 4206 /* Assume that server accepts the request */ 4207 success = 1; 4208 if (success) { 4209 /* Record that connection to this host/port is permitted. */ 4210 host_to_connect = listen_host = listen_path = NULL; 4211 port_to_connect = listen_port = 0; 4212 if (fwd->connect_path != NULL) { 4213 host_to_connect = fwd->connect_path; 4214 port_to_connect = PORT_STREAMLOCAL; 4215 } else { 4216 host_to_connect = fwd->connect_host; 4217 port_to_connect = fwd->connect_port; 4218 } 4219 if (fwd->listen_path != NULL) { 4220 listen_path = fwd->listen_path; 4221 listen_port = PORT_STREAMLOCAL; 4222 } else { 4223 listen_host = fwd->listen_host; 4224 listen_port = fwd->listen_port; 4225 } 4226 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4227 host_to_connect, port_to_connect, 4228 listen_host, listen_path, listen_port, NULL); 4229 } 4230 return idx; 4231 } 4232 4233 static int 4234 open_match(struct permission *allowed_open, const char *requestedhost, 4235 int requestedport) 4236 { 4237 if (allowed_open->host_to_connect == NULL) 4238 return 0; 4239 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4240 allowed_open->port_to_connect != requestedport) 4241 return 0; 4242 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4243 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4244 return 0; 4245 return 1; 4246 } 4247 4248 /* 4249 * Note that in the listen host/port case 4250 * we don't support FWD_PERMIT_ANY_PORT and 4251 * need to translate between the configured-host (listen_host) 4252 * and what we've sent to the remote server (channel_rfwd_bind_host) 4253 */ 4254 static int 4255 open_listen_match_tcpip(struct permission *allowed_open, 4256 const char *requestedhost, u_short requestedport, int translate) 4257 { 4258 const char *allowed_host; 4259 4260 if (allowed_open->host_to_connect == NULL) 4261 return 0; 4262 if (allowed_open->listen_port != requestedport) 4263 return 0; 4264 if (!translate && allowed_open->listen_host == NULL && 4265 requestedhost == NULL) 4266 return 1; 4267 allowed_host = translate ? 4268 channel_rfwd_bind_host(allowed_open->listen_host) : 4269 allowed_open->listen_host; 4270 if (allowed_host == NULL || requestedhost == NULL || 4271 strcmp(allowed_host, requestedhost) != 0) 4272 return 0; 4273 return 1; 4274 } 4275 4276 static int 4277 open_listen_match_streamlocal(struct permission *allowed_open, 4278 const char *requestedpath) 4279 { 4280 if (allowed_open->host_to_connect == NULL) 4281 return 0; 4282 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4283 return 0; 4284 if (allowed_open->listen_path == NULL || 4285 strcmp(allowed_open->listen_path, requestedpath) != 0) 4286 return 0; 4287 return 1; 4288 } 4289 4290 /* 4291 * Request cancellation of remote forwarding of connection host:port from 4292 * local side. 4293 */ 4294 static int 4295 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4296 const char *host, u_short port) 4297 { 4298 struct ssh_channels *sc = ssh->chanctxt; 4299 struct permission_set *pset = &sc->local_perms; 4300 int r; 4301 u_int i; 4302 struct permission *perm = NULL; 4303 4304 for (i = 0; i < pset->num_permitted_user; i++) { 4305 perm = &pset->permitted_user[i]; 4306 if (open_listen_match_tcpip(perm, host, port, 0)) 4307 break; 4308 perm = NULL; 4309 } 4310 if (perm == NULL) { 4311 debug_f("requested forward not found"); 4312 return -1; 4313 } 4314 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4315 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4316 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4317 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4318 (r = sshpkt_put_u32(ssh, port)) != 0 || 4319 (r = sshpkt_send(ssh)) != 0) 4320 fatal_fr(r, "send cancel"); 4321 4322 fwd_perm_clear(perm); /* unregister */ 4323 4324 return 0; 4325 } 4326 4327 /* 4328 * Request cancellation of remote forwarding of Unix domain socket 4329 * path from local side. 4330 */ 4331 static int 4332 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4333 { 4334 struct ssh_channels *sc = ssh->chanctxt; 4335 struct permission_set *pset = &sc->local_perms; 4336 int r; 4337 u_int i; 4338 struct permission *perm = NULL; 4339 4340 for (i = 0; i < pset->num_permitted_user; i++) { 4341 perm = &pset->permitted_user[i]; 4342 if (open_listen_match_streamlocal(perm, path)) 4343 break; 4344 perm = NULL; 4345 } 4346 if (perm == NULL) { 4347 debug_f("requested forward not found"); 4348 return -1; 4349 } 4350 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4351 (r = sshpkt_put_cstring(ssh, 4352 "cancel-streamlocal-forward@openssh.com")) != 0 || 4353 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4354 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4355 (r = sshpkt_send(ssh)) != 0) 4356 fatal_fr(r, "send cancel"); 4357 4358 fwd_perm_clear(perm); /* unregister */ 4359 4360 return 0; 4361 } 4362 4363 /* 4364 * Request cancellation of remote forwarding of a connection from local side. 4365 */ 4366 int 4367 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4368 { 4369 if (fwd->listen_path != NULL) { 4370 return channel_request_rforward_cancel_streamlocal(ssh, 4371 fwd->listen_path); 4372 } else { 4373 return channel_request_rforward_cancel_tcpip(ssh, 4374 fwd->listen_host, 4375 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4376 } 4377 } 4378 4379 /* 4380 * Permits opening to any host/port if permitted_user[] is empty. This is 4381 * usually called by the server, because the user could connect to any port 4382 * anyway, and the server has no way to know but to trust the client anyway. 4383 */ 4384 void 4385 channel_permit_all(struct ssh *ssh, int where) 4386 { 4387 struct permission_set *pset = permission_set_get(ssh, where); 4388 4389 if (pset->num_permitted_user == 0) 4390 pset->all_permitted = 1; 4391 } 4392 4393 /* 4394 * Permit the specified host/port for forwarding. 4395 */ 4396 void 4397 channel_add_permission(struct ssh *ssh, int who, int where, 4398 char *host, int port) 4399 { 4400 int local = where == FORWARD_LOCAL; 4401 struct permission_set *pset = permission_set_get(ssh, where); 4402 4403 debug("allow %s forwarding to host %s port %d", 4404 fwd_ident(who, where), host, port); 4405 /* 4406 * Remote forwards set listen_host/port, local forwards set 4407 * host/port_to_connect. 4408 */ 4409 permission_set_add(ssh, who, where, 4410 local ? host : 0, local ? port : 0, 4411 local ? NULL : host, NULL, local ? 0 : port, NULL); 4412 pset->all_permitted = 0; 4413 } 4414 4415 /* 4416 * Administratively disable forwarding. 4417 */ 4418 void 4419 channel_disable_admin(struct ssh *ssh, int where) 4420 { 4421 channel_clear_permission(ssh, FORWARD_ADM, where); 4422 permission_set_add(ssh, FORWARD_ADM, where, 4423 NULL, 0, NULL, NULL, 0, NULL); 4424 } 4425 4426 /* 4427 * Clear a list of permitted opens. 4428 */ 4429 void 4430 channel_clear_permission(struct ssh *ssh, int who, int where) 4431 { 4432 struct permission **permp; 4433 u_int *npermp; 4434 4435 permission_set_get_array(ssh, who, where, &permp, &npermp); 4436 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4437 *npermp = 0; 4438 } 4439 4440 /* 4441 * Update the listen port for a dynamic remote forward, after 4442 * the actual 'newport' has been allocated. If 'newport' < 0 is 4443 * passed then they entry will be invalidated. 4444 */ 4445 void 4446 channel_update_permission(struct ssh *ssh, int idx, int newport) 4447 { 4448 struct permission_set *pset = &ssh->chanctxt->local_perms; 4449 4450 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4451 debug_f("index out of range: %d num_permitted_user %d", 4452 idx, pset->num_permitted_user); 4453 return; 4454 } 4455 debug("%s allowed port %d for forwarding to host %s port %d", 4456 newport > 0 ? "Updating" : "Removing", 4457 newport, 4458 pset->permitted_user[idx].host_to_connect, 4459 pset->permitted_user[idx].port_to_connect); 4460 if (newport <= 0) 4461 fwd_perm_clear(&pset->permitted_user[idx]); 4462 else { 4463 pset->permitted_user[idx].listen_port = 4464 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4465 } 4466 } 4467 4468 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4469 int 4470 permitopen_port(const char *p) 4471 { 4472 int port; 4473 4474 if (strcmp(p, "*") == 0) 4475 return FWD_PERMIT_ANY_PORT; 4476 if ((port = a2port(p)) > 0) 4477 return port; 4478 return -1; 4479 } 4480 4481 /* Try to start non-blocking connect to next host in cctx list */ 4482 static int 4483 connect_next(struct channel_connect *cctx) 4484 { 4485 int sock, saved_errno; 4486 struct sockaddr_un *sunaddr; 4487 char ntop[NI_MAXHOST]; 4488 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4489 4490 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4491 switch (cctx->ai->ai_family) { 4492 case AF_UNIX: 4493 /* unix:pathname instead of host:port */ 4494 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4495 strlcpy(ntop, "unix", sizeof(ntop)); 4496 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4497 break; 4498 case AF_INET: 4499 case AF_INET6: 4500 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4501 ntop, sizeof(ntop), strport, sizeof(strport), 4502 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4503 error_f("getnameinfo failed"); 4504 continue; 4505 } 4506 break; 4507 default: 4508 continue; 4509 } 4510 debug_f("start for host %.100s ([%.100s]:%s)", 4511 cctx->host, ntop, strport); 4512 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4513 cctx->ai->ai_protocol)) == -1) { 4514 if (cctx->ai->ai_next == NULL) 4515 error("socket: %.100s", strerror(errno)); 4516 else 4517 verbose("socket: %.100s", strerror(errno)); 4518 continue; 4519 } 4520 if (set_nonblock(sock) == -1) 4521 fatal_f("set_nonblock(%d)", sock); 4522 if (connect(sock, cctx->ai->ai_addr, 4523 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4524 debug_f("host %.100s ([%.100s]:%s): %.100s", 4525 cctx->host, ntop, strport, strerror(errno)); 4526 saved_errno = errno; 4527 close(sock); 4528 errno = saved_errno; 4529 continue; /* fail -- try next */ 4530 } 4531 if (cctx->ai->ai_family != AF_UNIX) 4532 set_nodelay(sock); 4533 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4534 cctx->host, ntop, strport, sock); 4535 cctx->ai = cctx->ai->ai_next; 4536 return sock; 4537 } 4538 return -1; 4539 } 4540 4541 static void 4542 channel_connect_ctx_free(struct channel_connect *cctx) 4543 { 4544 free(cctx->host); 4545 if (cctx->aitop) { 4546 if (cctx->aitop->ai_family == AF_UNIX) 4547 free(cctx->aitop); 4548 else 4549 freeaddrinfo(cctx->aitop); 4550 } 4551 memset(cctx, 0, sizeof(*cctx)); 4552 } 4553 4554 /* 4555 * Return connecting socket to remote host:port or local socket path, 4556 * passing back the failure reason if appropriate. 4557 */ 4558 static int 4559 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4560 char *ctype, char *rname, struct channel_connect *cctx, 4561 int *reason, const char **errmsg) 4562 { 4563 struct addrinfo hints; 4564 int gaierr; 4565 int sock = -1; 4566 char strport[NI_MAXSERV]; 4567 4568 if (port == PORT_STREAMLOCAL) { 4569 struct sockaddr_un *sunaddr; 4570 struct addrinfo *ai; 4571 4572 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4573 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4574 return -1; 4575 } 4576 4577 /* 4578 * Fake up a struct addrinfo for AF_UNIX connections. 4579 * channel_connect_ctx_free() must check ai_family 4580 * and use free() not freeaddirinfo() for AF_UNIX. 4581 */ 4582 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4583 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4584 ai->ai_addr = (struct sockaddr *)(ai + 1); 4585 ai->ai_addrlen = sizeof(*sunaddr); 4586 ai->ai_family = AF_UNIX; 4587 ai->ai_socktype = socktype; 4588 ai->ai_protocol = PF_UNSPEC; 4589 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4590 sunaddr->sun_family = AF_UNIX; 4591 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4592 cctx->aitop = ai; 4593 } else { 4594 memset(&hints, 0, sizeof(hints)); 4595 hints.ai_family = ssh->chanctxt->IPv4or6; 4596 hints.ai_socktype = socktype; 4597 snprintf(strport, sizeof strport, "%d", port); 4598 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4599 != 0) { 4600 if (errmsg != NULL) 4601 *errmsg = ssh_gai_strerror(gaierr); 4602 if (reason != NULL) 4603 *reason = SSH2_OPEN_CONNECT_FAILED; 4604 error("connect_to %.100s: unknown host (%s)", name, 4605 ssh_gai_strerror(gaierr)); 4606 return -1; 4607 } 4608 } 4609 4610 cctx->host = xstrdup(name); 4611 cctx->port = port; 4612 cctx->ai = cctx->aitop; 4613 4614 if ((sock = connect_next(cctx)) == -1) { 4615 error("connect to %.100s port %d failed: %s", 4616 name, port, strerror(errno)); 4617 return -1; 4618 } 4619 4620 return sock; 4621 } 4622 4623 /* Return CONNECTING channel to remote host:port or local socket path */ 4624 static Channel * 4625 connect_to(struct ssh *ssh, const char *host, int port, 4626 char *ctype, char *rname) 4627 { 4628 struct channel_connect cctx; 4629 Channel *c; 4630 int sock; 4631 4632 memset(&cctx, 0, sizeof(cctx)); 4633 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4634 &cctx, NULL, NULL); 4635 if (sock == -1) { 4636 channel_connect_ctx_free(&cctx); 4637 return NULL; 4638 } 4639 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4640 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4641 c->host_port = port; 4642 c->path = xstrdup(host); 4643 c->connect_ctx = cctx; 4644 4645 return c; 4646 } 4647 4648 /* 4649 * returns either the newly connected channel or the downstream channel 4650 * that needs to deal with this connection. 4651 */ 4652 Channel * 4653 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4654 u_short listen_port, char *ctype, char *rname) 4655 { 4656 struct ssh_channels *sc = ssh->chanctxt; 4657 struct permission_set *pset = &sc->local_perms; 4658 u_int i; 4659 struct permission *perm; 4660 4661 for (i = 0; i < pset->num_permitted_user; i++) { 4662 perm = &pset->permitted_user[i]; 4663 if (open_listen_match_tcpip(perm, 4664 listen_host, listen_port, 1)) { 4665 if (perm->downstream) 4666 return perm->downstream; 4667 if (perm->port_to_connect == 0) 4668 return rdynamic_connect_prepare(ssh, 4669 ctype, rname); 4670 return connect_to(ssh, 4671 perm->host_to_connect, perm->port_to_connect, 4672 ctype, rname); 4673 } 4674 } 4675 error("WARNING: Server requests forwarding for unknown listen_port %d", 4676 listen_port); 4677 return NULL; 4678 } 4679 4680 Channel * 4681 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4682 char *ctype, char *rname) 4683 { 4684 struct ssh_channels *sc = ssh->chanctxt; 4685 struct permission_set *pset = &sc->local_perms; 4686 u_int i; 4687 struct permission *perm; 4688 4689 for (i = 0; i < pset->num_permitted_user; i++) { 4690 perm = &pset->permitted_user[i]; 4691 if (open_listen_match_streamlocal(perm, path)) { 4692 return connect_to(ssh, 4693 perm->host_to_connect, perm->port_to_connect, 4694 ctype, rname); 4695 } 4696 } 4697 error("WARNING: Server requests forwarding for unknown path %.100s", 4698 path); 4699 return NULL; 4700 } 4701 4702 /* Check if connecting to that port is permitted and connect. */ 4703 Channel * 4704 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4705 char *ctype, char *rname, int *reason, const char **errmsg) 4706 { 4707 struct ssh_channels *sc = ssh->chanctxt; 4708 struct permission_set *pset = &sc->local_perms; 4709 struct channel_connect cctx; 4710 Channel *c; 4711 u_int i, permit, permit_adm = 1; 4712 int sock; 4713 struct permission *perm; 4714 4715 permit = pset->all_permitted; 4716 if (!permit) { 4717 for (i = 0; i < pset->num_permitted_user; i++) { 4718 perm = &pset->permitted_user[i]; 4719 if (open_match(perm, host, port)) { 4720 permit = 1; 4721 break; 4722 } 4723 } 4724 } 4725 4726 if (pset->num_permitted_admin > 0) { 4727 permit_adm = 0; 4728 for (i = 0; i < pset->num_permitted_admin; i++) { 4729 perm = &pset->permitted_admin[i]; 4730 if (open_match(perm, host, port)) { 4731 permit_adm = 1; 4732 break; 4733 } 4734 } 4735 } 4736 4737 if (!permit || !permit_adm) { 4738 logit("Received request from %.100s port %d to connect to " 4739 "host %.100s port %d, but the request was denied.", 4740 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4741 if (reason != NULL) 4742 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4743 return NULL; 4744 } 4745 4746 memset(&cctx, 0, sizeof(cctx)); 4747 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4748 &cctx, reason, errmsg); 4749 if (sock == -1) { 4750 channel_connect_ctx_free(&cctx); 4751 return NULL; 4752 } 4753 4754 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4755 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4756 c->host_port = port; 4757 c->path = xstrdup(host); 4758 c->connect_ctx = cctx; 4759 4760 return c; 4761 } 4762 4763 /* Check if connecting to that path is permitted and connect. */ 4764 Channel * 4765 channel_connect_to_path(struct ssh *ssh, const char *path, 4766 char *ctype, char *rname) 4767 { 4768 struct ssh_channels *sc = ssh->chanctxt; 4769 struct permission_set *pset = &sc->local_perms; 4770 u_int i, permit, permit_adm = 1; 4771 struct permission *perm; 4772 4773 permit = pset->all_permitted; 4774 if (!permit) { 4775 for (i = 0; i < pset->num_permitted_user; i++) { 4776 perm = &pset->permitted_user[i]; 4777 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4778 permit = 1; 4779 break; 4780 } 4781 } 4782 } 4783 4784 if (pset->num_permitted_admin > 0) { 4785 permit_adm = 0; 4786 for (i = 0; i < pset->num_permitted_admin; i++) { 4787 perm = &pset->permitted_admin[i]; 4788 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4789 permit_adm = 1; 4790 break; 4791 } 4792 } 4793 } 4794 4795 if (!permit || !permit_adm) { 4796 logit("Received request to connect to path %.100s, " 4797 "but the request was denied.", path); 4798 return NULL; 4799 } 4800 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4801 } 4802 4803 void 4804 channel_send_window_changes(struct ssh *ssh) 4805 { 4806 struct ssh_channels *sc = ssh->chanctxt; 4807 struct winsize ws; 4808 int r; 4809 u_int i; 4810 4811 for (i = 0; i < sc->channels_alloc; i++) { 4812 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4813 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4814 continue; 4815 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4816 continue; 4817 channel_request_start(ssh, i, "window-change", 0); 4818 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4819 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4820 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4821 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4822 (r = sshpkt_send(ssh)) != 0) 4823 fatal_fr(r, "channel %u; send window-change", i); 4824 } 4825 } 4826 4827 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4828 static Channel * 4829 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4830 { 4831 Channel *c; 4832 int r; 4833 4834 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4835 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4836 c->host_port = 0; 4837 c->path = NULL; 4838 4839 /* 4840 * We need to open the channel before we have a FD, 4841 * so that we can get SOCKS header from peer. 4842 */ 4843 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4844 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4845 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4846 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4847 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4848 fatal_fr(r, "channel %i; confirm", c->self); 4849 return c; 4850 } 4851 4852 /* Return CONNECTING socket to remote host:port or local socket path */ 4853 static int 4854 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4855 { 4856 struct ssh_channels *sc = ssh->chanctxt; 4857 struct permission_set *pset = &sc->local_perms; 4858 struct permission *perm; 4859 struct channel_connect cctx; 4860 u_int i, permit_adm = 1; 4861 int sock; 4862 4863 if (pset->num_permitted_admin > 0) { 4864 permit_adm = 0; 4865 for (i = 0; i < pset->num_permitted_admin; i++) { 4866 perm = &pset->permitted_admin[i]; 4867 if (open_match(perm, c->path, c->host_port)) { 4868 permit_adm = 1; 4869 break; 4870 } 4871 } 4872 } 4873 if (!permit_adm) { 4874 debug_f("requested forward not permitted"); 4875 return -1; 4876 } 4877 4878 memset(&cctx, 0, sizeof(cctx)); 4879 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4880 NULL, &cctx, NULL, NULL); 4881 if (sock == -1) 4882 channel_connect_ctx_free(&cctx); 4883 else { 4884 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4885 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4886 c->connect_ctx = cctx; 4887 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4888 } 4889 return sock; 4890 } 4891 4892 /* -- X11 forwarding */ 4893 4894 /* 4895 * Creates an internet domain socket for listening for X11 connections. 4896 * Returns 0 and a suitable display number for the DISPLAY variable 4897 * stored in display_numberp , or -1 if an error occurs. 4898 */ 4899 int 4900 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4901 int x11_use_localhost, int single_connection, 4902 u_int *display_numberp, int **chanids) 4903 { 4904 Channel *nc = NULL; 4905 int display_number, sock; 4906 u_short port; 4907 struct addrinfo hints, *ai, *aitop; 4908 char strport[NI_MAXSERV]; 4909 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4910 4911 if (chanids == NULL) 4912 return -1; 4913 4914 for (display_number = x11_display_offset; 4915 display_number < MAX_DISPLAYS; 4916 display_number++) { 4917 port = 6000 + display_number; 4918 memset(&hints, 0, sizeof(hints)); 4919 hints.ai_family = ssh->chanctxt->IPv4or6; 4920 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4921 hints.ai_socktype = SOCK_STREAM; 4922 snprintf(strport, sizeof strport, "%d", port); 4923 if ((gaierr = getaddrinfo(NULL, strport, 4924 &hints, &aitop)) != 0) { 4925 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4926 return -1; 4927 } 4928 for (ai = aitop; ai; ai = ai->ai_next) { 4929 if (ai->ai_family != AF_INET && 4930 ai->ai_family != AF_INET6) 4931 continue; 4932 sock = socket(ai->ai_family, ai->ai_socktype, 4933 ai->ai_protocol); 4934 if (sock == -1) { 4935 error("socket: %.100s", strerror(errno)); 4936 freeaddrinfo(aitop); 4937 return -1; 4938 } 4939 set_reuseaddr(sock); 4940 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4941 debug2_f("bind port %d: %.100s", port, 4942 strerror(errno)); 4943 close(sock); 4944 for (n = 0; n < num_socks; n++) 4945 close(socks[n]); 4946 num_socks = 0; 4947 break; 4948 } 4949 socks[num_socks++] = sock; 4950 if (num_socks == NUM_SOCKS) 4951 break; 4952 } 4953 freeaddrinfo(aitop); 4954 if (num_socks > 0) 4955 break; 4956 } 4957 if (display_number >= MAX_DISPLAYS) { 4958 error("Failed to allocate internet-domain X11 display socket."); 4959 return -1; 4960 } 4961 /* Start listening for connections on the socket. */ 4962 for (n = 0; n < num_socks; n++) { 4963 sock = socks[n]; 4964 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 4965 error("listen: %.100s", strerror(errno)); 4966 close(sock); 4967 return -1; 4968 } 4969 } 4970 4971 /* Allocate a channel for each socket. */ 4972 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 4973 for (n = 0; n < num_socks; n++) { 4974 sock = socks[n]; 4975 nc = channel_new(ssh, "x11-listener", 4976 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4977 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 4978 0, "X11 inet listener", 1); 4979 nc->single_connection = single_connection; 4980 (*chanids)[n] = nc->self; 4981 } 4982 (*chanids)[n] = -1; 4983 4984 /* Return the display number for the DISPLAY environment variable. */ 4985 *display_numberp = display_number; 4986 return 0; 4987 } 4988 4989 static int 4990 connect_local_xsocket(u_int dnr) 4991 { 4992 int sock; 4993 struct sockaddr_un addr; 4994 4995 sock = socket(AF_UNIX, SOCK_STREAM, 0); 4996 if (sock == -1) 4997 error("socket: %.100s", strerror(errno)); 4998 memset(&addr, 0, sizeof(addr)); 4999 addr.sun_family = AF_UNIX; 5000 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 5001 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5002 return sock; 5003 close(sock); 5004 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5005 return -1; 5006 } 5007 5008 int 5009 x11_connect_display(struct ssh *ssh) 5010 { 5011 u_int display_number; 5012 const char *display; 5013 char buf[1024], *cp; 5014 struct addrinfo hints, *ai, *aitop; 5015 char strport[NI_MAXSERV]; 5016 int gaierr, sock = 0; 5017 5018 /* Try to open a socket for the local X server. */ 5019 display = getenv("DISPLAY"); 5020 if (!display) { 5021 error("DISPLAY not set."); 5022 return -1; 5023 } 5024 /* 5025 * Now we decode the value of the DISPLAY variable and make a 5026 * connection to the real X server. 5027 */ 5028 5029 /* 5030 * Check if it is a unix domain socket. Unix domain displays are in 5031 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5032 */ 5033 if (strncmp(display, "unix:", 5) == 0 || 5034 display[0] == ':') { 5035 /* Connect to the unix domain socket. */ 5036 if (sscanf(strrchr(display, ':') + 1, "%u", 5037 &display_number) != 1) { 5038 error("Could not parse display number from DISPLAY: " 5039 "%.100s", display); 5040 return -1; 5041 } 5042 /* Create a socket. */ 5043 sock = connect_local_xsocket(display_number); 5044 if (sock < 0) 5045 return -1; 5046 5047 /* OK, we now have a connection to the display. */ 5048 return sock; 5049 } 5050 /* 5051 * Connect to an inet socket. The DISPLAY value is supposedly 5052 * hostname:d[.s], where hostname may also be numeric IP address. 5053 */ 5054 strlcpy(buf, display, sizeof(buf)); 5055 cp = strchr(buf, ':'); 5056 if (!cp) { 5057 error("Could not find ':' in DISPLAY: %.100s", display); 5058 return -1; 5059 } 5060 *cp = 0; 5061 /* 5062 * buf now contains the host name. But first we parse the 5063 * display number. 5064 */ 5065 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5066 error("Could not parse display number from DISPLAY: %.100s", 5067 display); 5068 return -1; 5069 } 5070 5071 /* Look up the host address */ 5072 memset(&hints, 0, sizeof(hints)); 5073 hints.ai_family = ssh->chanctxt->IPv4or6; 5074 hints.ai_socktype = SOCK_STREAM; 5075 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5076 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5077 error("%.100s: unknown host. (%s)", buf, 5078 ssh_gai_strerror(gaierr)); 5079 return -1; 5080 } 5081 for (ai = aitop; ai; ai = ai->ai_next) { 5082 /* Create a socket. */ 5083 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5084 if (sock == -1) { 5085 debug2("socket: %.100s", strerror(errno)); 5086 continue; 5087 } 5088 /* Connect it to the display. */ 5089 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5090 debug2("connect %.100s port %u: %.100s", buf, 5091 6000 + display_number, strerror(errno)); 5092 close(sock); 5093 continue; 5094 } 5095 /* Success */ 5096 break; 5097 } 5098 freeaddrinfo(aitop); 5099 if (!ai) { 5100 error("connect %.100s port %u: %.100s", buf, 5101 6000 + display_number, strerror(errno)); 5102 return -1; 5103 } 5104 set_nodelay(sock); 5105 return sock; 5106 } 5107 5108 /* 5109 * Requests forwarding of X11 connections, generates fake authentication 5110 * data, and enables authentication spoofing. 5111 * This should be called in the client only. 5112 */ 5113 void 5114 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5115 const char *disp, const char *proto, const char *data, int want_reply) 5116 { 5117 struct ssh_channels *sc = ssh->chanctxt; 5118 u_int data_len = (u_int) strlen(data) / 2; 5119 u_int i, value; 5120 const char *cp; 5121 char *new_data; 5122 int r, screen_number; 5123 5124 if (sc->x11_saved_display == NULL) 5125 sc->x11_saved_display = xstrdup(disp); 5126 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5127 error("x11_request_forwarding_with_spoofing: different " 5128 "$DISPLAY already forwarded"); 5129 return; 5130 } 5131 5132 cp = strchr(disp, ':'); 5133 if (cp) 5134 cp = strchr(cp, '.'); 5135 if (cp) 5136 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5137 else 5138 screen_number = 0; 5139 5140 if (sc->x11_saved_proto == NULL) { 5141 /* Save protocol name. */ 5142 sc->x11_saved_proto = xstrdup(proto); 5143 5144 /* Extract real authentication data. */ 5145 sc->x11_saved_data = xmalloc(data_len); 5146 for (i = 0; i < data_len; i++) { 5147 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5148 fatal("x11_request_forwarding: bad " 5149 "authentication data: %.100s", data); 5150 } 5151 sc->x11_saved_data[i] = value; 5152 } 5153 sc->x11_saved_data_len = data_len; 5154 5155 /* Generate fake data of the same length. */ 5156 sc->x11_fake_data = xmalloc(data_len); 5157 arc4random_buf(sc->x11_fake_data, data_len); 5158 sc->x11_fake_data_len = data_len; 5159 } 5160 5161 /* Convert the fake data into hex. */ 5162 new_data = tohex(sc->x11_fake_data, data_len); 5163 5164 /* Send the request packet. */ 5165 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5166 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5167 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5168 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5169 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5170 (r = sshpkt_send(ssh)) != 0 || 5171 (r = ssh_packet_write_wait(ssh)) != 0) 5172 fatal_fr(r, "send x11-req"); 5173 free(new_data); 5174 } 5175