1 /* $OpenBSD: channels.c,v 1.435 2023/12/18 14:47:20 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include "includes.h" 43 44 #include <sys/types.h> 45 #include <sys/stat.h> 46 #include <sys/ioctl.h> 47 #include <sys/un.h> 48 #include <sys/socket.h> 49 #ifdef HAVE_SYS_TIME_H 50 # include <sys/time.h> 51 #endif 52 53 #include <netinet/in.h> 54 #include <arpa/inet.h> 55 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <limits.h> 59 #include <netdb.h> 60 #ifdef HAVE_POLL_H 61 #include <poll.h> 62 #endif 63 #include <stdarg.h> 64 #ifdef HAVE_STDINT_H 65 # include <stdint.h> 66 #endif 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <string.h> 70 #include <termios.h> 71 #include <unistd.h> 72 73 #include "openbsd-compat/sys-queue.h" 74 #include "xmalloc.h" 75 #include "ssh.h" 76 #include "ssh2.h" 77 #include "ssherr.h" 78 #include "sshbuf.h" 79 #include "packet.h" 80 #include "log.h" 81 #include "misc.h" 82 #include "channels.h" 83 #include "compat.h" 84 #include "canohost.h" 85 #include "sshkey.h" 86 #include "authfd.h" 87 #include "pathnames.h" 88 #include "match.h" 89 90 /* XXX remove once we're satisfied there's no lurking bugs */ 91 /* #define DEBUG_CHANNEL_POLL 1 */ 92 93 /* -- agent forwarding */ 94 #define NUM_SOCKS 10 95 96 /* -- tcp forwarding */ 97 /* special-case port number meaning allow any port */ 98 #define FWD_PERMIT_ANY_PORT 0 99 100 /* special-case wildcard meaning allow any host */ 101 #define FWD_PERMIT_ANY_HOST "*" 102 103 /* -- X11 forwarding */ 104 /* Maximum number of fake X11 displays to try. */ 105 #define MAX_DISPLAYS 1000 106 107 /* Per-channel callback for pre/post IO actions */ 108 typedef void chan_fn(struct ssh *, Channel *c); 109 110 /* 111 * Data structure for storing which hosts are permitted for forward requests. 112 * The local sides of any remote forwards are stored in this array to prevent 113 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 114 * network (which might be behind a firewall). 115 */ 116 /* XXX: streamlocal wants a path instead of host:port */ 117 /* Overload host_to_connect; we could just make this match Forward */ 118 /* XXX - can we use listen_host instead of listen_path? */ 119 struct permission { 120 char *host_to_connect; /* Connect to 'host'. */ 121 int port_to_connect; /* Connect to 'port'. */ 122 char *listen_host; /* Remote side should listen address. */ 123 char *listen_path; /* Remote side should listen path. */ 124 int listen_port; /* Remote side should listen port. */ 125 Channel *downstream; /* Downstream mux*/ 126 }; 127 128 /* 129 * Stores the forwarding permission state for a single direction (local or 130 * remote). 131 */ 132 struct permission_set { 133 /* 134 * List of all local permitted host/port pairs to allow for the 135 * user. 136 */ 137 u_int num_permitted_user; 138 struct permission *permitted_user; 139 140 /* 141 * List of all permitted host/port pairs to allow for the admin. 142 */ 143 u_int num_permitted_admin; 144 struct permission *permitted_admin; 145 146 /* 147 * If this is true, all opens/listens are permitted. This is the 148 * case on the server on which we have to trust the client anyway, 149 * and the user could do anything after logging in. 150 */ 151 int all_permitted; 152 }; 153 154 /* Used to record timeouts per channel type */ 155 struct ssh_channel_timeout { 156 char *type_pattern; 157 int timeout_secs; 158 }; 159 160 /* Master structure for channels state */ 161 struct ssh_channels { 162 /* 163 * Pointer to an array containing all allocated channels. The array 164 * is dynamically extended as needed. 165 */ 166 Channel **channels; 167 168 /* 169 * Size of the channel array. All slots of the array must always be 170 * initialized (at least the type field); unused slots set to NULL 171 */ 172 u_int channels_alloc; 173 174 /* 175 * 'channel_pre*' are called just before IO to add any bits 176 * relevant to channels in the c->io_want bitmasks. 177 * 178 * 'channel_post*': perform any appropriate operations for 179 * channels which have c->io_ready events pending. 180 */ 181 chan_fn **channel_pre; 182 chan_fn **channel_post; 183 184 /* -- tcp forwarding */ 185 struct permission_set local_perms; 186 struct permission_set remote_perms; 187 188 /* -- X11 forwarding */ 189 190 /* Saved X11 local (client) display. */ 191 char *x11_saved_display; 192 193 /* Saved X11 authentication protocol name. */ 194 char *x11_saved_proto; 195 196 /* Saved X11 authentication data. This is the real data. */ 197 char *x11_saved_data; 198 u_int x11_saved_data_len; 199 200 /* Deadline after which all X11 connections are refused */ 201 time_t x11_refuse_time; 202 203 /* 204 * Fake X11 authentication data. This is what the server will be 205 * sending us; we should replace any occurrences of this by the 206 * real data. 207 */ 208 u_char *x11_fake_data; 209 u_int x11_fake_data_len; 210 211 /* AF_UNSPEC or AF_INET or AF_INET6 */ 212 int IPv4or6; 213 214 /* Channel timeouts by type */ 215 struct ssh_channel_timeout *timeouts; 216 size_t ntimeouts; 217 }; 218 219 /* helper */ 220 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 221 static const char *channel_rfwd_bind_host(const char *listen_host); 222 223 /* non-blocking connect helpers */ 224 static int connect_next(struct channel_connect *); 225 static void channel_connect_ctx_free(struct channel_connect *); 226 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 227 static int rdynamic_connect_finish(struct ssh *, Channel *); 228 229 /* Setup helper */ 230 static void channel_handler_init(struct ssh_channels *sc); 231 232 /* -- channel core */ 233 234 void 235 channel_init_channels(struct ssh *ssh) 236 { 237 struct ssh_channels *sc; 238 239 if ((sc = calloc(1, sizeof(*sc))) == NULL) 240 fatal_f("allocation failed"); 241 sc->channels_alloc = 10; 242 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 243 sc->IPv4or6 = AF_UNSPEC; 244 channel_handler_init(sc); 245 246 ssh->chanctxt = sc; 247 } 248 249 Channel * 250 channel_by_id(struct ssh *ssh, int id) 251 { 252 Channel *c; 253 254 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 255 logit_f("%d: bad id", id); 256 return NULL; 257 } 258 c = ssh->chanctxt->channels[id]; 259 if (c == NULL) { 260 logit_f("%d: bad id: channel free", id); 261 return NULL; 262 } 263 return c; 264 } 265 266 Channel * 267 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 268 { 269 Channel *c; 270 u_int i; 271 272 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 273 c = ssh->chanctxt->channels[i]; 274 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 275 return c; 276 } 277 return NULL; 278 } 279 280 /* 281 * Returns the channel if it is allowed to receive protocol messages. 282 * Private channels, like listening sockets, may not receive messages. 283 */ 284 Channel * 285 channel_lookup(struct ssh *ssh, int id) 286 { 287 Channel *c; 288 289 if ((c = channel_by_id(ssh, id)) == NULL) 290 return NULL; 291 292 switch (c->type) { 293 case SSH_CHANNEL_X11_OPEN: 294 case SSH_CHANNEL_LARVAL: 295 case SSH_CHANNEL_CONNECTING: 296 case SSH_CHANNEL_DYNAMIC: 297 case SSH_CHANNEL_RDYNAMIC_OPEN: 298 case SSH_CHANNEL_RDYNAMIC_FINISH: 299 case SSH_CHANNEL_OPENING: 300 case SSH_CHANNEL_OPEN: 301 case SSH_CHANNEL_ABANDONED: 302 case SSH_CHANNEL_MUX_PROXY: 303 return c; 304 } 305 logit("Non-public channel %d, type %d.", id, c->type); 306 return NULL; 307 } 308 309 /* 310 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 311 * match type_pattern. 312 */ 313 void 314 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 315 int timeout_secs) 316 { 317 struct ssh_channels *sc = ssh->chanctxt; 318 319 debug2_f("channel type \"%s\" timeout %d seconds", 320 type_pattern, timeout_secs); 321 sc->timeouts = xrecallocarray(sc->timeouts, sc->ntimeouts, 322 sc->ntimeouts + 1, sizeof(*sc->timeouts)); 323 sc->timeouts[sc->ntimeouts].type_pattern = xstrdup(type_pattern); 324 sc->timeouts[sc->ntimeouts].timeout_secs = timeout_secs; 325 sc->ntimeouts++; 326 } 327 328 /* Clears all previously-added channel timeouts */ 329 void 330 channel_clear_timeouts(struct ssh *ssh) 331 { 332 struct ssh_channels *sc = ssh->chanctxt; 333 size_t i; 334 335 debug3_f("clearing"); 336 for (i = 0; i < sc->ntimeouts; i++) 337 free(sc->timeouts[i].type_pattern); 338 free(sc->timeouts); 339 sc->timeouts = NULL; 340 sc->ntimeouts = 0; 341 } 342 343 static int 344 lookup_timeout(struct ssh *ssh, const char *type) 345 { 346 struct ssh_channels *sc = ssh->chanctxt; 347 size_t i; 348 349 for (i = 0; i < sc->ntimeouts; i++) { 350 if (match_pattern(type, sc->timeouts[i].type_pattern)) 351 return sc->timeouts[i].timeout_secs; 352 } 353 354 return 0; 355 } 356 357 /* 358 * Sets "extended type" of a channel; used by session layer to add additional 359 * information about channel types (e.g. shell, login, subsystem) that can then 360 * be used to select timeouts. 361 * Will reset c->inactive_deadline as a side-effect. 362 */ 363 void 364 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 365 { 366 Channel *c; 367 368 if ((c = channel_by_id(ssh, id)) == NULL) 369 fatal_f("missing channel %d", id); 370 if (c->xctype != NULL) 371 free(c->xctype); 372 c->xctype = xstrdup(xctype); 373 /* Type has changed, so look up inactivity deadline again */ 374 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 375 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 376 c->inactive_deadline); 377 } 378 379 /* 380 * Register filedescriptors for a channel, used when allocating a channel or 381 * when the channel consumer/producer is ready, e.g. shell exec'd 382 */ 383 static void 384 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 385 int extusage, int nonblock, int is_tty) 386 { 387 int val; 388 389 if (rfd != -1) 390 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 391 if (wfd != -1 && wfd != rfd) 392 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 393 if (efd != -1 && efd != rfd && efd != wfd) 394 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 395 396 c->rfd = rfd; 397 c->wfd = wfd; 398 c->sock = (rfd == wfd) ? rfd : -1; 399 c->efd = efd; 400 c->extended_usage = extusage; 401 402 if ((c->isatty = is_tty) != 0) 403 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 404 #ifdef _AIX 405 /* XXX: Later AIX versions can't push as much data to tty */ 406 c->wfd_isatty = is_tty || isatty(c->wfd); 407 #endif 408 409 /* enable nonblocking mode */ 410 c->restore_block = 0; 411 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 412 /* 413 * Special handling for stdio file descriptors: do not set 414 * non-blocking mode if they are TTYs. Otherwise prepare to 415 * restore their blocking state on exit to avoid interfering 416 * with other programs that follow. 417 */ 418 if (rfd != -1 && !isatty(rfd) && 419 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 420 c->restore_flags[0] = val; 421 c->restore_block |= CHANNEL_RESTORE_RFD; 422 set_nonblock(rfd); 423 } 424 if (wfd != -1 && !isatty(wfd) && 425 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 426 c->restore_flags[1] = val; 427 c->restore_block |= CHANNEL_RESTORE_WFD; 428 set_nonblock(wfd); 429 } 430 if (efd != -1 && !isatty(efd) && 431 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 432 c->restore_flags[2] = val; 433 c->restore_block |= CHANNEL_RESTORE_EFD; 434 set_nonblock(efd); 435 } 436 } else if (nonblock) { 437 if (rfd != -1) 438 set_nonblock(rfd); 439 if (wfd != -1) 440 set_nonblock(wfd); 441 if (efd != -1) 442 set_nonblock(efd); 443 } 444 } 445 446 /* 447 * Allocate a new channel object and set its type and socket. 448 */ 449 Channel * 450 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 451 u_int window, u_int maxpack, int extusage, const char *remote_name, 452 int nonblock) 453 { 454 struct ssh_channels *sc = ssh->chanctxt; 455 u_int i, found = 0; 456 Channel *c; 457 int r; 458 459 /* Try to find a free slot where to put the new channel. */ 460 for (i = 0; i < sc->channels_alloc; i++) { 461 if (sc->channels[i] == NULL) { 462 /* Found a free slot. */ 463 found = i; 464 break; 465 } 466 } 467 if (i >= sc->channels_alloc) { 468 /* 469 * There are no free slots. Take last+1 slot and expand 470 * the array. 471 */ 472 found = sc->channels_alloc; 473 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 474 fatal_f("internal error: channels_alloc %d too big", 475 sc->channels_alloc); 476 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 477 sc->channels_alloc + 10, sizeof(*sc->channels)); 478 sc->channels_alloc += 10; 479 debug2("channel: expanding %d", sc->channels_alloc); 480 } 481 /* Initialize and return new channel. */ 482 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 483 if ((c->input = sshbuf_new()) == NULL || 484 (c->output = sshbuf_new()) == NULL || 485 (c->extended = sshbuf_new()) == NULL) 486 fatal_f("sshbuf_new failed"); 487 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 488 fatal_fr(r, "sshbuf_set_max_size"); 489 c->ostate = CHAN_OUTPUT_OPEN; 490 c->istate = CHAN_INPUT_OPEN; 491 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 492 c->self = found; 493 c->type = type; 494 c->ctype = ctype; 495 c->local_window = window; 496 c->local_window_max = window; 497 c->local_maxpacket = maxpack; 498 c->remote_name = xstrdup(remote_name); 499 c->ctl_chan = -1; 500 c->delayed = 1; /* prevent call to channel_post handler */ 501 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 502 TAILQ_INIT(&c->status_confirms); 503 debug("channel %d: new %s [%s] (inactive timeout: %u)", 504 found, c->ctype, remote_name, c->inactive_deadline); 505 return c; 506 } 507 508 int 509 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 510 { 511 int ret, fd = *fdp; 512 513 if (fd == -1) 514 return 0; 515 516 /* restore blocking */ 517 if (*fdp == c->rfd && 518 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 519 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 520 else if (*fdp == c->wfd && 521 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 522 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 523 else if (*fdp == c->efd && 524 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 525 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 526 527 if (*fdp == c->rfd) { 528 c->io_want &= ~SSH_CHAN_IO_RFD; 529 c->io_ready &= ~SSH_CHAN_IO_RFD; 530 c->rfd = -1; 531 c->pfds[0] = -1; 532 } 533 if (*fdp == c->wfd) { 534 c->io_want &= ~SSH_CHAN_IO_WFD; 535 c->io_ready &= ~SSH_CHAN_IO_WFD; 536 c->wfd = -1; 537 c->pfds[1] = -1; 538 } 539 if (*fdp == c->efd) { 540 c->io_want &= ~SSH_CHAN_IO_EFD; 541 c->io_ready &= ~SSH_CHAN_IO_EFD; 542 c->efd = -1; 543 c->pfds[2] = -1; 544 } 545 if (*fdp == c->sock) { 546 c->io_want &= ~SSH_CHAN_IO_SOCK; 547 c->io_ready &= ~SSH_CHAN_IO_SOCK; 548 c->sock = -1; 549 c->pfds[3] = -1; 550 } 551 552 ret = close(fd); 553 *fdp = -1; /* probably redundant */ 554 return ret; 555 } 556 557 /* Close all channel fd/socket. */ 558 static void 559 channel_close_fds(struct ssh *ssh, Channel *c) 560 { 561 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 562 563 channel_close_fd(ssh, c, &c->sock); 564 if (rfd != sock) 565 channel_close_fd(ssh, c, &c->rfd); 566 if (wfd != sock && wfd != rfd) 567 channel_close_fd(ssh, c, &c->wfd); 568 if (efd != sock && efd != rfd && efd != wfd) 569 channel_close_fd(ssh, c, &c->efd); 570 } 571 572 static void 573 fwd_perm_clear(struct permission *perm) 574 { 575 free(perm->host_to_connect); 576 free(perm->listen_host); 577 free(perm->listen_path); 578 memset(perm, 0, sizeof(*perm)); 579 } 580 581 /* Returns an printable name for the specified forwarding permission list */ 582 static const char * 583 fwd_ident(int who, int where) 584 { 585 if (who == FORWARD_ADM) { 586 if (where == FORWARD_LOCAL) 587 return "admin local"; 588 else if (where == FORWARD_REMOTE) 589 return "admin remote"; 590 } else if (who == FORWARD_USER) { 591 if (where == FORWARD_LOCAL) 592 return "user local"; 593 else if (where == FORWARD_REMOTE) 594 return "user remote"; 595 } 596 fatal("Unknown forward permission list %d/%d", who, where); 597 } 598 599 /* Returns the forwarding permission list for the specified direction */ 600 static struct permission_set * 601 permission_set_get(struct ssh *ssh, int where) 602 { 603 struct ssh_channels *sc = ssh->chanctxt; 604 605 switch (where) { 606 case FORWARD_LOCAL: 607 return &sc->local_perms; 608 break; 609 case FORWARD_REMOTE: 610 return &sc->remote_perms; 611 break; 612 default: 613 fatal_f("invalid forwarding direction %d", where); 614 } 615 } 616 617 /* Returns pointers to the specified forwarding list and its element count */ 618 static void 619 permission_set_get_array(struct ssh *ssh, int who, int where, 620 struct permission ***permpp, u_int **npermpp) 621 { 622 struct permission_set *pset = permission_set_get(ssh, where); 623 624 switch (who) { 625 case FORWARD_USER: 626 *permpp = &pset->permitted_user; 627 *npermpp = &pset->num_permitted_user; 628 break; 629 case FORWARD_ADM: 630 *permpp = &pset->permitted_admin; 631 *npermpp = &pset->num_permitted_admin; 632 break; 633 default: 634 fatal_f("invalid forwarding client %d", who); 635 } 636 } 637 638 /* Adds an entry to the specified forwarding list */ 639 static int 640 permission_set_add(struct ssh *ssh, int who, int where, 641 const char *host_to_connect, int port_to_connect, 642 const char *listen_host, const char *listen_path, int listen_port, 643 Channel *downstream) 644 { 645 struct permission **permp; 646 u_int n, *npermp; 647 648 permission_set_get_array(ssh, who, where, &permp, &npermp); 649 650 if (*npermp >= INT_MAX) 651 fatal_f("%s overflow", fwd_ident(who, where)); 652 653 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 654 n = (*npermp)++; 655 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 656 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 657 (*permp)[n].port_to_connect = port_to_connect; 658 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 659 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 660 (*permp)[n].listen_port = listen_port; 661 (*permp)[n].downstream = downstream; 662 #undef MAYBE_DUP 663 return (int)n; 664 } 665 666 static void 667 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 668 { 669 struct ssh_channels *sc = ssh->chanctxt; 670 struct permission_set *pset = &sc->local_perms; 671 struct permission *perm; 672 int r; 673 u_int i; 674 675 for (i = 0; i < pset->num_permitted_user; i++) { 676 perm = &pset->permitted_user[i]; 677 if (perm->downstream != c) 678 continue; 679 680 /* cancel on the server, since mux client is gone */ 681 debug("channel %d: cleanup remote forward for %s:%u", 682 c->self, perm->listen_host, perm->listen_port); 683 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 684 (r = sshpkt_put_cstring(ssh, 685 "cancel-tcpip-forward")) != 0 || 686 (r = sshpkt_put_u8(ssh, 0)) != 0 || 687 (r = sshpkt_put_cstring(ssh, 688 channel_rfwd_bind_host(perm->listen_host))) != 0 || 689 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 690 (r = sshpkt_send(ssh)) != 0) { 691 fatal_fr(r, "channel %i", c->self); 692 } 693 fwd_perm_clear(perm); /* unregister */ 694 } 695 } 696 697 /* Free the channel and close its fd/socket. */ 698 void 699 channel_free(struct ssh *ssh, Channel *c) 700 { 701 struct ssh_channels *sc = ssh->chanctxt; 702 char *s; 703 u_int i, n; 704 Channel *other; 705 struct channel_confirm *cc; 706 707 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 708 if ((other = sc->channels[i]) == NULL) 709 continue; 710 n++; 711 /* detach from mux client and prepare for closing */ 712 if (c->type == SSH_CHANNEL_MUX_CLIENT && 713 other->type == SSH_CHANNEL_MUX_PROXY && 714 other->mux_ctx == c) { 715 other->mux_ctx = NULL; 716 other->type = SSH_CHANNEL_OPEN; 717 other->istate = CHAN_INPUT_CLOSED; 718 other->ostate = CHAN_OUTPUT_CLOSED; 719 } 720 } 721 debug("channel %d: free: %s, nchannels %u", c->self, 722 c->remote_name ? c->remote_name : "???", n); 723 724 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 725 mux_remove_remote_forwardings(ssh, c); 726 free(c->mux_ctx); 727 c->mux_ctx = NULL; 728 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 729 free(c->mux_ctx); 730 c->mux_ctx = NULL; 731 } 732 733 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 734 s = channel_open_message(ssh); 735 debug3("channel %d: status: %s", c->self, s); 736 free(s); 737 } 738 739 channel_close_fds(ssh, c); 740 sshbuf_free(c->input); 741 sshbuf_free(c->output); 742 sshbuf_free(c->extended); 743 c->input = c->output = c->extended = NULL; 744 free(c->remote_name); 745 c->remote_name = NULL; 746 free(c->path); 747 c->path = NULL; 748 free(c->listening_addr); 749 c->listening_addr = NULL; 750 free(c->xctype); 751 c->xctype = NULL; 752 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 753 if (cc->abandon_cb != NULL) 754 cc->abandon_cb(ssh, c, cc->ctx); 755 TAILQ_REMOVE(&c->status_confirms, cc, entry); 756 freezero(cc, sizeof(*cc)); 757 } 758 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 759 c->filter_cleanup(ssh, c->self, c->filter_ctx); 760 sc->channels[c->self] = NULL; 761 freezero(c, sizeof(*c)); 762 } 763 764 void 765 channel_free_all(struct ssh *ssh) 766 { 767 u_int i; 768 struct ssh_channels *sc = ssh->chanctxt; 769 770 for (i = 0; i < sc->channels_alloc; i++) 771 if (sc->channels[i] != NULL) 772 channel_free(ssh, sc->channels[i]); 773 774 free(sc->channels); 775 sc->channels = NULL; 776 sc->channels_alloc = 0; 777 778 free(sc->x11_saved_display); 779 sc->x11_saved_display = NULL; 780 781 free(sc->x11_saved_proto); 782 sc->x11_saved_proto = NULL; 783 784 free(sc->x11_saved_data); 785 sc->x11_saved_data = NULL; 786 sc->x11_saved_data_len = 0; 787 788 free(sc->x11_fake_data); 789 sc->x11_fake_data = NULL; 790 sc->x11_fake_data_len = 0; 791 } 792 793 /* 794 * Closes the sockets/fds of all channels. This is used to close extra file 795 * descriptors after a fork. 796 */ 797 void 798 channel_close_all(struct ssh *ssh) 799 { 800 u_int i; 801 802 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 803 if (ssh->chanctxt->channels[i] != NULL) 804 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 805 } 806 807 /* 808 * Stop listening to channels. 809 */ 810 void 811 channel_stop_listening(struct ssh *ssh) 812 { 813 u_int i; 814 Channel *c; 815 816 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 817 c = ssh->chanctxt->channels[i]; 818 if (c != NULL) { 819 switch (c->type) { 820 case SSH_CHANNEL_AUTH_SOCKET: 821 case SSH_CHANNEL_PORT_LISTENER: 822 case SSH_CHANNEL_RPORT_LISTENER: 823 case SSH_CHANNEL_X11_LISTENER: 824 case SSH_CHANNEL_UNIX_LISTENER: 825 case SSH_CHANNEL_RUNIX_LISTENER: 826 channel_close_fd(ssh, c, &c->sock); 827 channel_free(ssh, c); 828 break; 829 } 830 } 831 } 832 } 833 834 /* 835 * Returns true if no channel has too much buffered data, and false if one or 836 * more channel is overfull. 837 */ 838 int 839 channel_not_very_much_buffered_data(struct ssh *ssh) 840 { 841 u_int i; 842 u_int maxsize = ssh_packet_get_maxsize(ssh); 843 Channel *c; 844 845 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 846 c = ssh->chanctxt->channels[i]; 847 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 848 continue; 849 if (sshbuf_len(c->output) > maxsize) { 850 debug2("channel %d: big output buffer %zu > %u", 851 c->self, sshbuf_len(c->output), maxsize); 852 return 0; 853 } 854 } 855 return 1; 856 } 857 858 /* Returns true if any channel is still open. */ 859 int 860 channel_still_open(struct ssh *ssh) 861 { 862 u_int i; 863 Channel *c; 864 865 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 866 c = ssh->chanctxt->channels[i]; 867 if (c == NULL) 868 continue; 869 switch (c->type) { 870 case SSH_CHANNEL_X11_LISTENER: 871 case SSH_CHANNEL_PORT_LISTENER: 872 case SSH_CHANNEL_RPORT_LISTENER: 873 case SSH_CHANNEL_MUX_LISTENER: 874 case SSH_CHANNEL_CLOSED: 875 case SSH_CHANNEL_AUTH_SOCKET: 876 case SSH_CHANNEL_DYNAMIC: 877 case SSH_CHANNEL_RDYNAMIC_OPEN: 878 case SSH_CHANNEL_CONNECTING: 879 case SSH_CHANNEL_ZOMBIE: 880 case SSH_CHANNEL_ABANDONED: 881 case SSH_CHANNEL_UNIX_LISTENER: 882 case SSH_CHANNEL_RUNIX_LISTENER: 883 continue; 884 case SSH_CHANNEL_LARVAL: 885 continue; 886 case SSH_CHANNEL_OPENING: 887 case SSH_CHANNEL_OPEN: 888 case SSH_CHANNEL_RDYNAMIC_FINISH: 889 case SSH_CHANNEL_X11_OPEN: 890 case SSH_CHANNEL_MUX_CLIENT: 891 case SSH_CHANNEL_MUX_PROXY: 892 return 1; 893 default: 894 fatal_f("bad channel type %d", c->type); 895 /* NOTREACHED */ 896 } 897 } 898 return 0; 899 } 900 901 /* Returns true if a channel with a TTY is open. */ 902 int 903 channel_tty_open(struct ssh *ssh) 904 { 905 u_int i; 906 Channel *c; 907 908 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 909 c = ssh->chanctxt->channels[i]; 910 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 911 continue; 912 if (c->client_tty) 913 return 1; 914 } 915 return 0; 916 } 917 918 /* Returns the id of an open channel suitable for keepaliving */ 919 int 920 channel_find_open(struct ssh *ssh) 921 { 922 u_int i; 923 Channel *c; 924 925 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 926 c = ssh->chanctxt->channels[i]; 927 if (c == NULL || !c->have_remote_id) 928 continue; 929 switch (c->type) { 930 case SSH_CHANNEL_CLOSED: 931 case SSH_CHANNEL_DYNAMIC: 932 case SSH_CHANNEL_RDYNAMIC_OPEN: 933 case SSH_CHANNEL_RDYNAMIC_FINISH: 934 case SSH_CHANNEL_X11_LISTENER: 935 case SSH_CHANNEL_PORT_LISTENER: 936 case SSH_CHANNEL_RPORT_LISTENER: 937 case SSH_CHANNEL_MUX_LISTENER: 938 case SSH_CHANNEL_MUX_CLIENT: 939 case SSH_CHANNEL_MUX_PROXY: 940 case SSH_CHANNEL_OPENING: 941 case SSH_CHANNEL_CONNECTING: 942 case SSH_CHANNEL_ZOMBIE: 943 case SSH_CHANNEL_ABANDONED: 944 case SSH_CHANNEL_UNIX_LISTENER: 945 case SSH_CHANNEL_RUNIX_LISTENER: 946 continue; 947 case SSH_CHANNEL_LARVAL: 948 case SSH_CHANNEL_AUTH_SOCKET: 949 case SSH_CHANNEL_OPEN: 950 case SSH_CHANNEL_X11_OPEN: 951 return i; 952 default: 953 fatal_f("bad channel type %d", c->type); 954 /* NOTREACHED */ 955 } 956 } 957 return -1; 958 } 959 960 /* Returns the state of the channel's extended usage flag */ 961 const char * 962 channel_format_extended_usage(const Channel *c) 963 { 964 if (c->efd == -1) 965 return "closed"; 966 967 switch (c->extended_usage) { 968 case CHAN_EXTENDED_WRITE: 969 return "write"; 970 case CHAN_EXTENDED_READ: 971 return "read"; 972 case CHAN_EXTENDED_IGNORE: 973 return "ignore"; 974 default: 975 return "UNKNOWN"; 976 } 977 } 978 979 static char * 980 channel_format_status(const Channel *c) 981 { 982 char *ret = NULL; 983 984 xasprintf(&ret, "t%d [%s] %s%u i%u/%zu o%u/%zu e[%s]/%zu " 985 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 986 c->type, c->xctype != NULL ? c->xctype : c->ctype, 987 c->have_remote_id ? "r" : "nr", c->remote_id, 988 c->istate, sshbuf_len(c->input), 989 c->ostate, sshbuf_len(c->output), 990 channel_format_extended_usage(c), sshbuf_len(c->extended), 991 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 992 c->io_want, c->io_ready); 993 return ret; 994 } 995 996 /* 997 * Returns a message describing the currently open forwarded connections, 998 * suitable for sending to the client. The message contains crlf pairs for 999 * newlines. 1000 */ 1001 char * 1002 channel_open_message(struct ssh *ssh) 1003 { 1004 struct sshbuf *buf; 1005 Channel *c; 1006 u_int i; 1007 int r; 1008 char *cp, *ret; 1009 1010 if ((buf = sshbuf_new()) == NULL) 1011 fatal_f("sshbuf_new"); 1012 if ((r = sshbuf_putf(buf, 1013 "The following connections are open:\r\n")) != 0) 1014 fatal_fr(r, "sshbuf_putf"); 1015 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1016 c = ssh->chanctxt->channels[i]; 1017 if (c == NULL) 1018 continue; 1019 switch (c->type) { 1020 case SSH_CHANNEL_X11_LISTENER: 1021 case SSH_CHANNEL_PORT_LISTENER: 1022 case SSH_CHANNEL_RPORT_LISTENER: 1023 case SSH_CHANNEL_CLOSED: 1024 case SSH_CHANNEL_AUTH_SOCKET: 1025 case SSH_CHANNEL_ZOMBIE: 1026 case SSH_CHANNEL_ABANDONED: 1027 case SSH_CHANNEL_MUX_LISTENER: 1028 case SSH_CHANNEL_UNIX_LISTENER: 1029 case SSH_CHANNEL_RUNIX_LISTENER: 1030 continue; 1031 case SSH_CHANNEL_LARVAL: 1032 case SSH_CHANNEL_OPENING: 1033 case SSH_CHANNEL_CONNECTING: 1034 case SSH_CHANNEL_DYNAMIC: 1035 case SSH_CHANNEL_RDYNAMIC_OPEN: 1036 case SSH_CHANNEL_RDYNAMIC_FINISH: 1037 case SSH_CHANNEL_OPEN: 1038 case SSH_CHANNEL_X11_OPEN: 1039 case SSH_CHANNEL_MUX_PROXY: 1040 case SSH_CHANNEL_MUX_CLIENT: 1041 cp = channel_format_status(c); 1042 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1043 c->self, c->remote_name, cp)) != 0) { 1044 free(cp); 1045 fatal_fr(r, "sshbuf_putf"); 1046 } 1047 free(cp); 1048 continue; 1049 default: 1050 fatal_f("bad channel type %d", c->type); 1051 /* NOTREACHED */ 1052 } 1053 } 1054 if ((ret = sshbuf_dup_string(buf)) == NULL) 1055 fatal_f("sshbuf_dup_string"); 1056 sshbuf_free(buf); 1057 return ret; 1058 } 1059 1060 static void 1061 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1062 { 1063 int r; 1064 1065 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1066 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1067 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1068 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1069 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1070 fatal_r(r, "%s: channel %i: open", where, c->self); 1071 } 1072 } 1073 1074 void 1075 channel_send_open(struct ssh *ssh, int id) 1076 { 1077 Channel *c = channel_lookup(ssh, id); 1078 int r; 1079 1080 if (c == NULL) { 1081 logit("channel_send_open: %d: bad id", id); 1082 return; 1083 } 1084 debug2("channel %d: send open", id); 1085 open_preamble(ssh, __func__, c, c->ctype); 1086 if ((r = sshpkt_send(ssh)) != 0) 1087 fatal_fr(r, "channel %i", c->self); 1088 } 1089 1090 void 1091 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 1092 { 1093 Channel *c = channel_lookup(ssh, id); 1094 int r; 1095 1096 if (c == NULL) { 1097 logit_f("%d: unknown channel id", id); 1098 return; 1099 } 1100 if (!c->have_remote_id) 1101 fatal_f("channel %d: no remote id", c->self); 1102 1103 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1104 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1105 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1106 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1107 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1108 fatal_fr(r, "channel %i", c->self); 1109 } 1110 } 1111 1112 void 1113 channel_register_status_confirm(struct ssh *ssh, int id, 1114 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1115 { 1116 struct channel_confirm *cc; 1117 Channel *c; 1118 1119 if ((c = channel_lookup(ssh, id)) == NULL) 1120 fatal_f("%d: bad id", id); 1121 1122 cc = xcalloc(1, sizeof(*cc)); 1123 cc->cb = cb; 1124 cc->abandon_cb = abandon_cb; 1125 cc->ctx = ctx; 1126 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1127 } 1128 1129 void 1130 channel_register_open_confirm(struct ssh *ssh, int id, 1131 channel_open_fn *fn, void *ctx) 1132 { 1133 Channel *c = channel_lookup(ssh, id); 1134 1135 if (c == NULL) { 1136 logit_f("%d: bad id", id); 1137 return; 1138 } 1139 c->open_confirm = fn; 1140 c->open_confirm_ctx = ctx; 1141 } 1142 1143 void 1144 channel_register_cleanup(struct ssh *ssh, int id, 1145 channel_callback_fn *fn, int do_close) 1146 { 1147 Channel *c = channel_by_id(ssh, id); 1148 1149 if (c == NULL) { 1150 logit_f("%d: bad id", id); 1151 return; 1152 } 1153 c->detach_user = fn; 1154 c->detach_close = do_close; 1155 } 1156 1157 void 1158 channel_cancel_cleanup(struct ssh *ssh, int id) 1159 { 1160 Channel *c = channel_by_id(ssh, id); 1161 1162 if (c == NULL) { 1163 logit_f("%d: bad id", id); 1164 return; 1165 } 1166 c->detach_user = NULL; 1167 c->detach_close = 0; 1168 } 1169 1170 void 1171 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1172 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1173 { 1174 Channel *c = channel_lookup(ssh, id); 1175 1176 if (c == NULL) { 1177 logit_f("%d: bad id", id); 1178 return; 1179 } 1180 c->input_filter = ifn; 1181 c->output_filter = ofn; 1182 c->filter_ctx = ctx; 1183 c->filter_cleanup = cfn; 1184 } 1185 1186 void 1187 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1188 int extusage, int nonblock, int is_tty, u_int window_max) 1189 { 1190 Channel *c = channel_lookup(ssh, id); 1191 int r; 1192 1193 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1194 fatal("channel_activate for non-larval channel %d.", id); 1195 if (!c->have_remote_id) 1196 fatal_f("channel %d: no remote id", c->self); 1197 1198 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1199 c->type = SSH_CHANNEL_OPEN; 1200 c->lastused = monotime(); 1201 c->local_window = c->local_window_max = window_max; 1202 1203 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1204 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1205 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1206 (r = sshpkt_send(ssh)) != 0) 1207 fatal_fr(r, "channel %i", c->self); 1208 } 1209 1210 static void 1211 channel_pre_listener(struct ssh *ssh, Channel *c) 1212 { 1213 c->io_want = SSH_CHAN_IO_SOCK_R; 1214 } 1215 1216 static void 1217 channel_pre_connecting(struct ssh *ssh, Channel *c) 1218 { 1219 debug3("channel %d: waiting for connection", c->self); 1220 c->io_want = SSH_CHAN_IO_SOCK_W; 1221 } 1222 1223 static void 1224 channel_pre_open(struct ssh *ssh, Channel *c) 1225 { 1226 c->io_want = 0; 1227 if (c->istate == CHAN_INPUT_OPEN && 1228 c->remote_window > 0 && 1229 sshbuf_len(c->input) < c->remote_window && 1230 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1231 c->io_want |= SSH_CHAN_IO_RFD; 1232 if (c->ostate == CHAN_OUTPUT_OPEN || 1233 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1234 if (sshbuf_len(c->output) > 0) { 1235 c->io_want |= SSH_CHAN_IO_WFD; 1236 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1237 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1238 debug2("channel %d: " 1239 "obuf_empty delayed efd %d/(%zu)", c->self, 1240 c->efd, sshbuf_len(c->extended)); 1241 else 1242 chan_obuf_empty(ssh, c); 1243 } 1244 } 1245 /** XXX check close conditions, too */ 1246 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1247 c->ostate == CHAN_OUTPUT_CLOSED)) { 1248 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1249 sshbuf_len(c->extended) > 0) 1250 c->io_want |= SSH_CHAN_IO_EFD_W; 1251 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1252 (c->extended_usage == CHAN_EXTENDED_READ || 1253 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1254 sshbuf_len(c->extended) < c->remote_window) 1255 c->io_want |= SSH_CHAN_IO_EFD_R; 1256 } 1257 /* XXX: What about efd? races? */ 1258 } 1259 1260 /* 1261 * This is a special state for X11 authentication spoofing. An opened X11 1262 * connection (when authentication spoofing is being done) remains in this 1263 * state until the first packet has been completely read. The authentication 1264 * data in that packet is then substituted by the real data if it matches the 1265 * fake data, and the channel is put into normal mode. 1266 * XXX All this happens at the client side. 1267 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1268 */ 1269 static int 1270 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1271 { 1272 struct ssh_channels *sc = ssh->chanctxt; 1273 u_char *ucp; 1274 u_int proto_len, data_len; 1275 1276 /* Is this being called after the refusal deadline? */ 1277 if (sc->x11_refuse_time != 0 && 1278 monotime() >= sc->x11_refuse_time) { 1279 verbose("Rejected X11 connection after ForwardX11Timeout " 1280 "expired"); 1281 return -1; 1282 } 1283 1284 /* Check if the fixed size part of the packet is in buffer. */ 1285 if (sshbuf_len(b) < 12) 1286 return 0; 1287 1288 /* Parse the lengths of variable-length fields. */ 1289 ucp = sshbuf_mutable_ptr(b); 1290 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1291 proto_len = 256 * ucp[6] + ucp[7]; 1292 data_len = 256 * ucp[8] + ucp[9]; 1293 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1294 proto_len = ucp[6] + 256 * ucp[7]; 1295 data_len = ucp[8] + 256 * ucp[9]; 1296 } else { 1297 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1298 ucp[0]); 1299 return -1; 1300 } 1301 1302 /* Check if the whole packet is in buffer. */ 1303 if (sshbuf_len(b) < 1304 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1305 return 0; 1306 1307 /* Check if authentication protocol matches. */ 1308 if (proto_len != strlen(sc->x11_saved_proto) || 1309 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1310 debug2("X11 connection uses different authentication protocol."); 1311 return -1; 1312 } 1313 /* Check if authentication data matches our fake data. */ 1314 if (data_len != sc->x11_fake_data_len || 1315 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1316 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1317 debug2("X11 auth data does not match fake data."); 1318 return -1; 1319 } 1320 /* Check fake data length */ 1321 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1322 error("X11 fake_data_len %d != saved_data_len %d", 1323 sc->x11_fake_data_len, sc->x11_saved_data_len); 1324 return -1; 1325 } 1326 /* 1327 * Received authentication protocol and data match 1328 * our fake data. Substitute the fake data with real 1329 * data. 1330 */ 1331 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1332 sc->x11_saved_data, sc->x11_saved_data_len); 1333 return 1; 1334 } 1335 1336 void 1337 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1338 { 1339 debug3_f("channel %d: forcibly closing", c->self); 1340 if (c->istate == CHAN_INPUT_OPEN) 1341 chan_read_failed(ssh, c); 1342 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1343 sshbuf_reset(c->input); 1344 chan_ibuf_empty(ssh, c); 1345 } 1346 if (c->ostate == CHAN_OUTPUT_OPEN || 1347 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1348 sshbuf_reset(c->output); 1349 chan_write_failed(ssh, c); 1350 } 1351 if (c->detach_user) 1352 c->detach_user(ssh, c->self, 1, NULL); 1353 if (c->efd != -1) 1354 channel_close_fd(ssh, c, &c->efd); 1355 if (abandon) 1356 c->type = SSH_CHANNEL_ABANDONED; 1357 /* exempt from inactivity timeouts */ 1358 c->inactive_deadline = 0; 1359 c->lastused = 0; 1360 } 1361 1362 static void 1363 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1364 { 1365 int ret = x11_open_helper(ssh, c->output); 1366 1367 /* c->force_drain = 1; */ 1368 1369 if (ret == 1) { 1370 c->type = SSH_CHANNEL_OPEN; 1371 c->lastused = monotime(); 1372 channel_pre_open(ssh, c); 1373 } else if (ret == -1) { 1374 logit("X11 connection rejected because of wrong " 1375 "authentication."); 1376 debug2("X11 rejected %d i%d/o%d", 1377 c->self, c->istate, c->ostate); 1378 channel_force_close(ssh, c, 0); 1379 } 1380 } 1381 1382 static void 1383 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1384 { 1385 c->io_want = 0; 1386 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1387 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1388 c->io_want |= SSH_CHAN_IO_RFD; 1389 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1390 /* clear buffer immediately (discard any partial packet) */ 1391 sshbuf_reset(c->input); 1392 chan_ibuf_empty(ssh, c); 1393 /* Start output drain. XXX just kill chan? */ 1394 chan_rcvd_oclose(ssh, c); 1395 } 1396 if (c->ostate == CHAN_OUTPUT_OPEN || 1397 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1398 if (sshbuf_len(c->output) > 0) 1399 c->io_want |= SSH_CHAN_IO_WFD; 1400 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1401 chan_obuf_empty(ssh, c); 1402 } 1403 } 1404 1405 /* try to decode a socks4 header */ 1406 static int 1407 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1408 { 1409 const u_char *p; 1410 char *host; 1411 u_int len, have, i, found, need; 1412 char username[256]; 1413 struct { 1414 u_int8_t version; 1415 u_int8_t command; 1416 u_int16_t dest_port; 1417 struct in_addr dest_addr; 1418 } s4_req, s4_rsp; 1419 int r; 1420 1421 debug2("channel %d: decode socks4", c->self); 1422 1423 have = sshbuf_len(input); 1424 len = sizeof(s4_req); 1425 if (have < len) 1426 return 0; 1427 p = sshbuf_ptr(input); 1428 1429 need = 1; 1430 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1431 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1432 debug2("channel %d: socks4a request", c->self); 1433 /* ... and needs an extra string (the hostname) */ 1434 need = 2; 1435 } 1436 /* Check for terminating NUL on the string(s) */ 1437 for (found = 0, i = len; i < have; i++) { 1438 if (p[i] == '\0') { 1439 found++; 1440 if (found == need) 1441 break; 1442 } 1443 if (i > 1024) { 1444 /* the peer is probably sending garbage */ 1445 debug("channel %d: decode socks4: too long", 1446 c->self); 1447 return -1; 1448 } 1449 } 1450 if (found < need) 1451 return 0; 1452 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1453 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1454 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1455 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1456 debug_r(r, "channels %d: decode socks4", c->self); 1457 return -1; 1458 } 1459 have = sshbuf_len(input); 1460 p = sshbuf_ptr(input); 1461 if (memchr(p, '\0', have) == NULL) { 1462 error("channel %d: decode socks4: unterminated user", c->self); 1463 return -1; 1464 } 1465 len = strlen(p); 1466 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1467 len++; /* trailing '\0' */ 1468 strlcpy(username, p, sizeof(username)); 1469 if ((r = sshbuf_consume(input, len)) != 0) 1470 fatal_fr(r, "channel %d: consume", c->self); 1471 free(c->path); 1472 c->path = NULL; 1473 if (need == 1) { /* SOCKS4: one string */ 1474 host = inet_ntoa(s4_req.dest_addr); 1475 c->path = xstrdup(host); 1476 } else { /* SOCKS4A: two strings */ 1477 have = sshbuf_len(input); 1478 p = sshbuf_ptr(input); 1479 if (memchr(p, '\0', have) == NULL) { 1480 error("channel %d: decode socks4a: host not nul " 1481 "terminated", c->self); 1482 return -1; 1483 } 1484 len = strlen(p); 1485 debug2("channel %d: decode socks4a: host %s/%d", 1486 c->self, p, len); 1487 len++; /* trailing '\0' */ 1488 if (len > NI_MAXHOST) { 1489 error("channel %d: hostname \"%.100s\" too long", 1490 c->self, p); 1491 return -1; 1492 } 1493 c->path = xstrdup(p); 1494 if ((r = sshbuf_consume(input, len)) != 0) 1495 fatal_fr(r, "channel %d: consume", c->self); 1496 } 1497 c->host_port = ntohs(s4_req.dest_port); 1498 1499 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1500 c->self, c->path, c->host_port, s4_req.command); 1501 1502 if (s4_req.command != 1) { 1503 debug("channel %d: cannot handle: %s cn %d", 1504 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1505 return -1; 1506 } 1507 s4_rsp.version = 0; /* vn: 0 for reply */ 1508 s4_rsp.command = 90; /* cd: req granted */ 1509 s4_rsp.dest_port = 0; /* ignored */ 1510 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1511 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1512 fatal_fr(r, "channel %d: append reply", c->self); 1513 return 1; 1514 } 1515 1516 /* try to decode a socks5 header */ 1517 #define SSH_SOCKS5_AUTHDONE 0x1000 1518 #define SSH_SOCKS5_NOAUTH 0x00 1519 #define SSH_SOCKS5_IPV4 0x01 1520 #define SSH_SOCKS5_DOMAIN 0x03 1521 #define SSH_SOCKS5_IPV6 0x04 1522 #define SSH_SOCKS5_CONNECT 0x01 1523 #define SSH_SOCKS5_SUCCESS 0x00 1524 1525 static int 1526 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1527 { 1528 /* XXX use get/put_u8 instead of trusting struct padding */ 1529 struct { 1530 u_int8_t version; 1531 u_int8_t command; 1532 u_int8_t reserved; 1533 u_int8_t atyp; 1534 } s5_req, s5_rsp; 1535 u_int16_t dest_port; 1536 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1537 const u_char *p; 1538 u_int have, need, i, found, nmethods, addrlen, af; 1539 int r; 1540 1541 debug2("channel %d: decode socks5", c->self); 1542 p = sshbuf_ptr(input); 1543 if (p[0] != 0x05) 1544 return -1; 1545 have = sshbuf_len(input); 1546 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1547 /* format: ver | nmethods | methods */ 1548 if (have < 2) 1549 return 0; 1550 nmethods = p[1]; 1551 if (have < nmethods + 2) 1552 return 0; 1553 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1554 for (found = 0, i = 2; i < nmethods + 2; i++) { 1555 if (p[i] == SSH_SOCKS5_NOAUTH) { 1556 found = 1; 1557 break; 1558 } 1559 } 1560 if (!found) { 1561 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1562 c->self); 1563 return -1; 1564 } 1565 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1566 fatal_fr(r, "channel %d: consume", c->self); 1567 /* version, method */ 1568 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1569 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1570 fatal_fr(r, "channel %d: append reply", c->self); 1571 c->flags |= SSH_SOCKS5_AUTHDONE; 1572 debug2("channel %d: socks5 auth done", c->self); 1573 return 0; /* need more */ 1574 } 1575 debug2("channel %d: socks5 post auth", c->self); 1576 if (have < sizeof(s5_req)+1) 1577 return 0; /* need more */ 1578 memcpy(&s5_req, p, sizeof(s5_req)); 1579 if (s5_req.version != 0x05 || 1580 s5_req.command != SSH_SOCKS5_CONNECT || 1581 s5_req.reserved != 0x00) { 1582 debug2("channel %d: only socks5 connect supported", c->self); 1583 return -1; 1584 } 1585 switch (s5_req.atyp){ 1586 case SSH_SOCKS5_IPV4: 1587 addrlen = 4; 1588 af = AF_INET; 1589 break; 1590 case SSH_SOCKS5_DOMAIN: 1591 addrlen = p[sizeof(s5_req)]; 1592 af = -1; 1593 break; 1594 case SSH_SOCKS5_IPV6: 1595 addrlen = 16; 1596 af = AF_INET6; 1597 break; 1598 default: 1599 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1600 return -1; 1601 } 1602 need = sizeof(s5_req) + addrlen + 2; 1603 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1604 need++; 1605 if (have < need) 1606 return 0; 1607 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1608 fatal_fr(r, "channel %d: consume", c->self); 1609 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1610 /* host string length */ 1611 if ((r = sshbuf_consume(input, 1)) != 0) 1612 fatal_fr(r, "channel %d: consume", c->self); 1613 } 1614 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1615 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1616 debug_r(r, "channel %d: parse addr/port", c->self); 1617 return -1; 1618 } 1619 dest_addr[addrlen] = '\0'; 1620 free(c->path); 1621 c->path = NULL; 1622 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1623 if (addrlen >= NI_MAXHOST) { 1624 error("channel %d: dynamic request: socks5 hostname " 1625 "\"%.100s\" too long", c->self, dest_addr); 1626 return -1; 1627 } 1628 c->path = xstrdup(dest_addr); 1629 } else { 1630 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1631 return -1; 1632 c->path = xstrdup(ntop); 1633 } 1634 c->host_port = ntohs(dest_port); 1635 1636 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1637 c->self, c->path, c->host_port, s5_req.command); 1638 1639 s5_rsp.version = 0x05; 1640 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1641 s5_rsp.reserved = 0; /* ignored */ 1642 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1643 dest_port = 0; /* ignored */ 1644 1645 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1646 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1647 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1648 fatal_fr(r, "channel %d: append reply", c->self); 1649 return 1; 1650 } 1651 1652 Channel * 1653 channel_connect_stdio_fwd(struct ssh *ssh, 1654 const char *host_to_connect, int port_to_connect, 1655 int in, int out, int nonblock) 1656 { 1657 Channel *c; 1658 1659 debug_f("%s:%d", host_to_connect, port_to_connect); 1660 1661 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1662 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1663 0, "stdio-forward", nonblock); 1664 1665 c->path = xstrdup(host_to_connect); 1666 c->host_port = port_to_connect; 1667 c->listening_port = 0; 1668 c->force_drain = 1; 1669 1670 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1671 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1672 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1673 1674 return c; 1675 } 1676 1677 /* dynamic port forwarding */ 1678 static void 1679 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1680 { 1681 const u_char *p; 1682 u_int have; 1683 int ret; 1684 1685 c->io_want = 0; 1686 have = sshbuf_len(c->input); 1687 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1688 /* sshbuf_dump(c->input, stderr); */ 1689 /* check if the fixed size part of the packet is in buffer. */ 1690 if (have < 3) { 1691 /* need more */ 1692 c->io_want |= SSH_CHAN_IO_RFD; 1693 return; 1694 } 1695 /* try to guess the protocol */ 1696 p = sshbuf_ptr(c->input); 1697 /* XXX sshbuf_peek_u8? */ 1698 switch (p[0]) { 1699 case 0x04: 1700 ret = channel_decode_socks4(c, c->input, c->output); 1701 break; 1702 case 0x05: 1703 ret = channel_decode_socks5(c, c->input, c->output); 1704 break; 1705 default: 1706 ret = -1; 1707 break; 1708 } 1709 if (ret < 0) { 1710 chan_mark_dead(ssh, c); 1711 } else if (ret == 0) { 1712 debug2("channel %d: pre_dynamic: need more", c->self); 1713 /* need more */ 1714 c->io_want |= SSH_CHAN_IO_RFD; 1715 if (sshbuf_len(c->output)) 1716 c->io_want |= SSH_CHAN_IO_WFD; 1717 } else { 1718 /* switch to the next state */ 1719 c->type = SSH_CHANNEL_OPENING; 1720 port_open_helper(ssh, c, "direct-tcpip"); 1721 } 1722 } 1723 1724 /* simulate read-error */ 1725 static void 1726 rdynamic_close(struct ssh *ssh, Channel *c) 1727 { 1728 c->type = SSH_CHANNEL_OPEN; 1729 channel_force_close(ssh, c, 0); 1730 } 1731 1732 /* reverse dynamic port forwarding */ 1733 static void 1734 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1735 { 1736 const u_char *p; 1737 u_int have, len; 1738 int r, ret; 1739 1740 have = sshbuf_len(c->output); 1741 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1742 /* sshbuf_dump(c->output, stderr); */ 1743 /* EOF received */ 1744 if (c->flags & CHAN_EOF_RCVD) { 1745 if ((r = sshbuf_consume(c->output, have)) != 0) 1746 fatal_fr(r, "channel %d: consume", c->self); 1747 rdynamic_close(ssh, c); 1748 return; 1749 } 1750 /* check if the fixed size part of the packet is in buffer. */ 1751 if (have < 3) 1752 return; 1753 /* try to guess the protocol */ 1754 p = sshbuf_ptr(c->output); 1755 switch (p[0]) { 1756 case 0x04: 1757 /* switch input/output for reverse forwarding */ 1758 ret = channel_decode_socks4(c, c->output, c->input); 1759 break; 1760 case 0x05: 1761 ret = channel_decode_socks5(c, c->output, c->input); 1762 break; 1763 default: 1764 ret = -1; 1765 break; 1766 } 1767 if (ret < 0) { 1768 rdynamic_close(ssh, c); 1769 } else if (ret == 0) { 1770 debug2("channel %d: pre_rdynamic: need more", c->self); 1771 /* send socks request to peer */ 1772 len = sshbuf_len(c->input); 1773 if (len > 0 && len < c->remote_window) { 1774 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1775 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1776 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1777 (r = sshpkt_send(ssh)) != 0) { 1778 fatal_fr(r, "channel %i: rdynamic", c->self); 1779 } 1780 if ((r = sshbuf_consume(c->input, len)) != 0) 1781 fatal_fr(r, "channel %d: consume", c->self); 1782 c->remote_window -= len; 1783 } 1784 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1785 /* the connect failed */ 1786 rdynamic_close(ssh, c); 1787 } 1788 } 1789 1790 /* This is our fake X11 server socket. */ 1791 static void 1792 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1793 { 1794 Channel *nc; 1795 struct sockaddr_storage addr; 1796 int r, newsock, oerrno, remote_port; 1797 socklen_t addrlen; 1798 char buf[16384], *remote_ipaddr; 1799 1800 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1801 return; 1802 1803 debug("X11 connection requested."); 1804 addrlen = sizeof(addr); 1805 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1806 if (c->single_connection) { 1807 oerrno = errno; 1808 debug2("single_connection: closing X11 listener."); 1809 channel_close_fd(ssh, c, &c->sock); 1810 chan_mark_dead(ssh, c); 1811 errno = oerrno; 1812 } 1813 if (newsock == -1) { 1814 if (errno != EINTR && errno != EWOULDBLOCK && 1815 errno != ECONNABORTED) 1816 error("accept: %.100s", strerror(errno)); 1817 if (errno == EMFILE || errno == ENFILE) 1818 c->notbefore = monotime() + 1; 1819 return; 1820 } 1821 set_nodelay(newsock); 1822 remote_ipaddr = get_peer_ipaddr(newsock); 1823 remote_port = get_peer_port(newsock); 1824 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1825 remote_ipaddr, remote_port); 1826 1827 nc = channel_new(ssh, "x11-connection", 1828 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1829 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1830 open_preamble(ssh, __func__, nc, "x11"); 1831 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1832 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1833 fatal_fr(r, "channel %i: reply", c->self); 1834 } 1835 if ((r = sshpkt_send(ssh)) != 0) 1836 fatal_fr(r, "channel %i: send", c->self); 1837 free(remote_ipaddr); 1838 } 1839 1840 static void 1841 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1842 { 1843 char *local_ipaddr = get_local_ipaddr(c->sock); 1844 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1845 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1846 int remote_port = get_peer_port(c->sock); 1847 int r; 1848 1849 if (remote_port == -1) { 1850 /* Fake addr/port to appease peers that validate it (Tectia) */ 1851 free(remote_ipaddr); 1852 remote_ipaddr = xstrdup("127.0.0.1"); 1853 remote_port = 65535; 1854 } 1855 1856 free(c->remote_name); 1857 xasprintf(&c->remote_name, 1858 "%s: listening port %d for %.100s port %d, " 1859 "connect from %.200s port %d to %.100s port %d", 1860 rtype, c->listening_port, c->path, c->host_port, 1861 remote_ipaddr, remote_port, local_ipaddr, local_port); 1862 1863 open_preamble(ssh, __func__, c, rtype); 1864 if (strcmp(rtype, "direct-tcpip") == 0) { 1865 /* target host, port */ 1866 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1867 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1868 fatal_fr(r, "channel %i: reply", c->self); 1869 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1870 /* target path */ 1871 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1872 fatal_fr(r, "channel %i: reply", c->self); 1873 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1874 /* listen path */ 1875 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1876 fatal_fr(r, "channel %i: reply", c->self); 1877 } else { 1878 /* listen address, port */ 1879 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1880 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1881 fatal_fr(r, "channel %i: reply", c->self); 1882 } 1883 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1884 /* reserved for future owner/mode info */ 1885 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1886 fatal_fr(r, "channel %i: reply", c->self); 1887 } else { 1888 /* originator host and port */ 1889 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1890 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1891 fatal_fr(r, "channel %i: reply", c->self); 1892 } 1893 if ((r = sshpkt_send(ssh)) != 0) 1894 fatal_fr(r, "channel %i: send", c->self); 1895 free(remote_ipaddr); 1896 free(local_ipaddr); 1897 } 1898 1899 void 1900 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 1901 { 1902 ssh->chanctxt->x11_refuse_time = refuse_time; 1903 } 1904 1905 /* 1906 * This socket is listening for connections to a forwarded TCP/IP port. 1907 */ 1908 static void 1909 channel_post_port_listener(struct ssh *ssh, Channel *c) 1910 { 1911 Channel *nc; 1912 struct sockaddr_storage addr; 1913 int newsock, nextstate; 1914 socklen_t addrlen; 1915 char *rtype; 1916 1917 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1918 return; 1919 1920 debug("Connection to port %d forwarding to %.100s port %d requested.", 1921 c->listening_port, c->path, c->host_port); 1922 1923 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1924 nextstate = SSH_CHANNEL_OPENING; 1925 rtype = "forwarded-tcpip"; 1926 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1927 nextstate = SSH_CHANNEL_OPENING; 1928 rtype = "forwarded-streamlocal@openssh.com"; 1929 } else if (c->host_port == PORT_STREAMLOCAL) { 1930 nextstate = SSH_CHANNEL_OPENING; 1931 rtype = "direct-streamlocal@openssh.com"; 1932 } else if (c->host_port == 0) { 1933 nextstate = SSH_CHANNEL_DYNAMIC; 1934 rtype = "dynamic-tcpip"; 1935 } else { 1936 nextstate = SSH_CHANNEL_OPENING; 1937 rtype = "direct-tcpip"; 1938 } 1939 1940 addrlen = sizeof(addr); 1941 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1942 if (newsock == -1) { 1943 if (errno != EINTR && errno != EWOULDBLOCK && 1944 errno != ECONNABORTED) 1945 error("accept: %.100s", strerror(errno)); 1946 if (errno == EMFILE || errno == ENFILE) 1947 c->notbefore = monotime() + 1; 1948 return; 1949 } 1950 if (c->host_port != PORT_STREAMLOCAL) 1951 set_nodelay(newsock); 1952 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1953 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1954 nc->listening_port = c->listening_port; 1955 nc->host_port = c->host_port; 1956 if (c->path != NULL) 1957 nc->path = xstrdup(c->path); 1958 1959 if (nextstate != SSH_CHANNEL_DYNAMIC) 1960 port_open_helper(ssh, nc, rtype); 1961 } 1962 1963 /* 1964 * This is the authentication agent socket listening for connections from 1965 * clients. 1966 */ 1967 static void 1968 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1969 { 1970 Channel *nc; 1971 int r, newsock; 1972 struct sockaddr_storage addr; 1973 socklen_t addrlen; 1974 1975 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1976 return; 1977 1978 addrlen = sizeof(addr); 1979 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1980 if (newsock == -1) { 1981 error("accept from auth socket: %.100s", strerror(errno)); 1982 if (errno == EMFILE || errno == ENFILE) 1983 c->notbefore = monotime() + 1; 1984 return; 1985 } 1986 nc = channel_new(ssh, "agent-connection", 1987 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1988 c->local_window_max, c->local_maxpacket, 1989 0, "accepted auth socket", 1); 1990 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1991 if ((r = sshpkt_send(ssh)) != 0) 1992 fatal_fr(r, "channel %i", c->self); 1993 } 1994 1995 static void 1996 channel_post_connecting(struct ssh *ssh, Channel *c) 1997 { 1998 int err = 0, sock, isopen, r; 1999 socklen_t sz = sizeof(err); 2000 2001 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2002 return; 2003 if (!c->have_remote_id) 2004 fatal_f("channel %d: no remote id", c->self); 2005 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2006 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2007 2008 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2009 err = errno; 2010 error("getsockopt SO_ERROR failed"); 2011 } 2012 2013 if (err == 0) { 2014 /* Non-blocking connection completed */ 2015 debug("channel %d: connected to %s port %d", 2016 c->self, c->connect_ctx.host, c->connect_ctx.port); 2017 channel_connect_ctx_free(&c->connect_ctx); 2018 c->type = SSH_CHANNEL_OPEN; 2019 c->lastused = monotime(); 2020 if (isopen) { 2021 /* no message necessary */ 2022 } else { 2023 if ((r = sshpkt_start(ssh, 2024 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2025 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2026 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2027 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2028 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2029 (r = sshpkt_send(ssh)) != 0) 2030 fatal_fr(r, "channel %i open confirm", c->self); 2031 } 2032 return; 2033 } 2034 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2035 return; 2036 2037 /* Non-blocking connection failed */ 2038 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2039 2040 /* Try next address, if any */ 2041 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2042 /* Exhausted all addresses for this destination */ 2043 error("connect_to %.100s port %d: failed.", 2044 c->connect_ctx.host, c->connect_ctx.port); 2045 channel_connect_ctx_free(&c->connect_ctx); 2046 if (isopen) { 2047 rdynamic_close(ssh, c); 2048 } else { 2049 if ((r = sshpkt_start(ssh, 2050 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2051 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2052 (r = sshpkt_put_u32(ssh, 2053 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2054 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2055 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2056 (r = sshpkt_send(ssh)) != 0) 2057 fatal_fr(r, "channel %i: failure", c->self); 2058 chan_mark_dead(ssh, c); 2059 } 2060 } 2061 2062 /* New non-blocking connection in progress */ 2063 close(c->sock); 2064 c->sock = c->rfd = c->wfd = sock; 2065 } 2066 2067 static int 2068 channel_handle_rfd(struct ssh *ssh, Channel *c) 2069 { 2070 char buf[CHAN_RBUF]; 2071 ssize_t len; 2072 int r, force; 2073 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2074 int pty_zeroread = 0; 2075 2076 #ifdef PTY_ZEROREAD 2077 /* Bug on AIX: read(1) can return 0 for a non-closed fd */ 2078 pty_zeroread = c->isatty; 2079 #endif 2080 2081 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2082 2083 if (!force && (c->io_ready & SSH_CHAN_IO_RFD) == 0) 2084 return 1; 2085 if ((avail = sshbuf_avail(c->input)) == 0) 2086 return 1; /* Shouldn't happen */ 2087 2088 /* 2089 * For "simple" channels (i.e. not datagram or filtered), we can 2090 * read directly to the channel buffer. 2091 */ 2092 if (!pty_zeroread && c->input_filter == NULL && !c->datagram) { 2093 /* Only OPEN channels have valid rwin */ 2094 if (c->type == SSH_CHANNEL_OPEN) { 2095 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2096 return 1; /* shouldn't happen */ 2097 if (maxlen > c->remote_window - have) 2098 maxlen = c->remote_window - have; 2099 } 2100 if (maxlen > avail) 2101 maxlen = avail; 2102 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2103 if (errno == EINTR || (!force && 2104 (errno == EAGAIN || errno == EWOULDBLOCK))) 2105 return 1; 2106 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2107 c->self, c->rfd, maxlen, ssh_err(r)); 2108 goto rfail; 2109 } 2110 if (nr != 0) 2111 c->lastused = monotime(); 2112 return 1; 2113 } 2114 2115 errno = 0; 2116 len = read(c->rfd, buf, sizeof(buf)); 2117 /* fixup AIX zero-length read with errno set to look more like errors */ 2118 if (pty_zeroread && len == 0 && errno != 0) 2119 len = -1; 2120 if (len == -1 && (errno == EINTR || 2121 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 2122 return 1; 2123 if (len < 0 || (!pty_zeroread && len == 0)) { 2124 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2125 c->self, c->rfd, len, 2126 len == 0 ? "closed" : strerror(errno)); 2127 rfail: 2128 if (c->type != SSH_CHANNEL_OPEN) { 2129 debug2("channel %d: not open", c->self); 2130 chan_mark_dead(ssh, c); 2131 return -1; 2132 } else { 2133 chan_read_failed(ssh, c); 2134 } 2135 return -1; 2136 } 2137 c->lastused = monotime(); 2138 if (c->input_filter != NULL) { 2139 if (c->input_filter(ssh, c, buf, len) == -1) { 2140 debug2("channel %d: filter stops", c->self); 2141 chan_read_failed(ssh, c); 2142 } 2143 } else if (c->datagram) { 2144 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2145 fatal_fr(r, "channel %i: put datagram", c->self); 2146 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2147 fatal_fr(r, "channel %i: put data", c->self); 2148 2149 return 1; 2150 } 2151 2152 static int 2153 channel_handle_wfd(struct ssh *ssh, Channel *c) 2154 { 2155 struct termios tio; 2156 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2157 size_t dlen, olen = 0; 2158 int r, len; 2159 2160 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2161 return 1; 2162 if (sshbuf_len(c->output) == 0) 2163 return 1; 2164 2165 /* Send buffered output data to the socket. */ 2166 olen = sshbuf_len(c->output); 2167 if (c->output_filter != NULL) { 2168 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2169 debug2("channel %d: filter stops", c->self); 2170 if (c->type != SSH_CHANNEL_OPEN) 2171 chan_mark_dead(ssh, c); 2172 else 2173 chan_write_failed(ssh, c); 2174 return -1; 2175 } 2176 } else if (c->datagram) { 2177 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2178 fatal_fr(r, "channel %i: get datagram", c->self); 2179 buf = data; 2180 } else { 2181 buf = data = sshbuf_mutable_ptr(c->output); 2182 dlen = sshbuf_len(c->output); 2183 } 2184 2185 if (c->datagram) { 2186 /* ignore truncated writes, datagrams might get lost */ 2187 len = write(c->wfd, buf, dlen); 2188 free(data); 2189 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2190 errno == EWOULDBLOCK)) 2191 return 1; 2192 if (len <= 0) 2193 goto write_fail; 2194 goto out; 2195 } 2196 2197 #ifdef _AIX 2198 /* XXX: Later AIX versions can't push as much data to tty */ 2199 if (c->wfd_isatty) 2200 dlen = MINIMUM(dlen, 8*1024); 2201 #endif 2202 2203 len = write(c->wfd, buf, dlen); 2204 if (len == -1 && 2205 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 2206 return 1; 2207 if (len <= 0) { 2208 write_fail: 2209 if (c->type != SSH_CHANNEL_OPEN) { 2210 debug2("channel %d: not open", c->self); 2211 chan_mark_dead(ssh, c); 2212 return -1; 2213 } else { 2214 chan_write_failed(ssh, c); 2215 } 2216 return -1; 2217 } 2218 c->lastused = monotime(); 2219 #ifndef BROKEN_TCGETATTR_ICANON 2220 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2221 if (tcgetattr(c->wfd, &tio) == 0 && 2222 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2223 /* 2224 * Simulate echo to reduce the impact of 2225 * traffic analysis. We need to match the 2226 * size of a SSH2_MSG_CHANNEL_DATA message 2227 * (4 byte channel id + buf) 2228 */ 2229 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2230 (r = sshpkt_send(ssh)) != 0) 2231 fatal_fr(r, "channel %i: ignore", c->self); 2232 } 2233 } 2234 #endif /* BROKEN_TCGETATTR_ICANON */ 2235 if ((r = sshbuf_consume(c->output, len)) != 0) 2236 fatal_fr(r, "channel %i: consume", c->self); 2237 out: 2238 c->local_consumed += olen - sshbuf_len(c->output); 2239 2240 return 1; 2241 } 2242 2243 static int 2244 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2245 { 2246 int r; 2247 ssize_t len; 2248 2249 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2250 return 1; 2251 if (sshbuf_len(c->extended) == 0) 2252 return 1; 2253 2254 len = write(c->efd, sshbuf_ptr(c->extended), 2255 sshbuf_len(c->extended)); 2256 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2257 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2258 errno == EWOULDBLOCK)) 2259 return 1; 2260 if (len <= 0) { 2261 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2262 channel_close_fd(ssh, c, &c->efd); 2263 } else { 2264 if ((r = sshbuf_consume(c->extended, len)) != 0) 2265 fatal_fr(r, "channel %i: consume", c->self); 2266 c->local_consumed += len; 2267 c->lastused = monotime(); 2268 } 2269 return 1; 2270 } 2271 2272 static int 2273 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2274 { 2275 char buf[CHAN_RBUF]; 2276 ssize_t len; 2277 int r, force; 2278 2279 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2280 2281 if (!force && (c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2282 return 1; 2283 2284 len = read(c->efd, buf, sizeof(buf)); 2285 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2286 if (len == -1 && (errno == EINTR || ((errno == EAGAIN || 2287 errno == EWOULDBLOCK) && !force))) 2288 return 1; 2289 if (len <= 0) { 2290 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2291 channel_close_fd(ssh, c, &c->efd); 2292 return 1; 2293 } 2294 c->lastused = monotime(); 2295 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2296 debug3("channel %d: discard efd", c->self); 2297 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2298 fatal_fr(r, "channel %i: append", c->self); 2299 return 1; 2300 } 2301 2302 static int 2303 channel_handle_efd(struct ssh *ssh, Channel *c) 2304 { 2305 if (c->efd == -1) 2306 return 1; 2307 2308 /** XXX handle drain efd, too */ 2309 2310 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2311 return channel_handle_efd_write(ssh, c); 2312 else if (c->extended_usage == CHAN_EXTENDED_READ || 2313 c->extended_usage == CHAN_EXTENDED_IGNORE) 2314 return channel_handle_efd_read(ssh, c); 2315 2316 return 1; 2317 } 2318 2319 static int 2320 channel_check_window(struct ssh *ssh, Channel *c) 2321 { 2322 int r; 2323 2324 if (c->type == SSH_CHANNEL_OPEN && 2325 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2326 ((c->local_window_max - c->local_window > 2327 c->local_maxpacket*3) || 2328 c->local_window < c->local_window_max/2) && 2329 c->local_consumed > 0) { 2330 if (!c->have_remote_id) 2331 fatal_f("channel %d: no remote id", c->self); 2332 if ((r = sshpkt_start(ssh, 2333 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2334 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2335 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2336 (r = sshpkt_send(ssh)) != 0) { 2337 fatal_fr(r, "channel %i", c->self); 2338 } 2339 debug2("channel %d: window %d sent adjust %d", c->self, 2340 c->local_window, c->local_consumed); 2341 c->local_window += c->local_consumed; 2342 c->local_consumed = 0; 2343 } 2344 return 1; 2345 } 2346 2347 static void 2348 channel_post_open(struct ssh *ssh, Channel *c) 2349 { 2350 channel_handle_rfd(ssh, c); 2351 channel_handle_wfd(ssh, c); 2352 channel_handle_efd(ssh, c); 2353 channel_check_window(ssh, c); 2354 } 2355 2356 static u_int 2357 read_mux(struct ssh *ssh, Channel *c, u_int need) 2358 { 2359 char buf[CHAN_RBUF]; 2360 ssize_t len; 2361 u_int rlen; 2362 int r; 2363 2364 if (sshbuf_len(c->input) < need) { 2365 rlen = need - sshbuf_len(c->input); 2366 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2367 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2368 return sshbuf_len(c->input); 2369 if (len <= 0) { 2370 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2371 c->self, c->rfd, len); 2372 chan_read_failed(ssh, c); 2373 return 0; 2374 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2375 fatal_fr(r, "channel %i: append", c->self); 2376 } 2377 return sshbuf_len(c->input); 2378 } 2379 2380 static void 2381 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2382 { 2383 u_int need; 2384 2385 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2386 return; 2387 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2388 return; 2389 if (c->mux_pause) 2390 return; 2391 2392 /* 2393 * Don't not read past the precise end of packets to 2394 * avoid disrupting fd passing. 2395 */ 2396 if (read_mux(ssh, c, 4) < 4) /* read header */ 2397 return; 2398 /* XXX sshbuf_peek_u32 */ 2399 need = PEEK_U32(sshbuf_ptr(c->input)); 2400 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2401 if (need > CHANNEL_MUX_MAX_PACKET) { 2402 debug2("channel %d: packet too big %u > %u", 2403 c->self, CHANNEL_MUX_MAX_PACKET, need); 2404 chan_rcvd_oclose(ssh, c); 2405 return; 2406 } 2407 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2408 return; 2409 if (c->mux_rcb(ssh, c) != 0) { 2410 debug("channel %d: mux_rcb failed", c->self); 2411 chan_mark_dead(ssh, c); 2412 return; 2413 } 2414 } 2415 2416 static void 2417 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2418 { 2419 ssize_t len; 2420 int r; 2421 2422 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2423 return; 2424 if (sshbuf_len(c->output) == 0) 2425 return; 2426 2427 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2428 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2429 return; 2430 if (len <= 0) { 2431 chan_mark_dead(ssh, c); 2432 return; 2433 } 2434 if ((r = sshbuf_consume(c->output, len)) != 0) 2435 fatal_fr(r, "channel %i: consume", c->self); 2436 } 2437 2438 static void 2439 channel_post_mux_client(struct ssh *ssh, Channel *c) 2440 { 2441 channel_post_mux_client_read(ssh, c); 2442 channel_post_mux_client_write(ssh, c); 2443 } 2444 2445 static void 2446 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2447 { 2448 Channel *nc; 2449 struct sockaddr_storage addr; 2450 socklen_t addrlen; 2451 int newsock; 2452 uid_t euid; 2453 gid_t egid; 2454 2455 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2456 return; 2457 2458 debug("multiplexing control connection"); 2459 2460 /* 2461 * Accept connection on control socket 2462 */ 2463 memset(&addr, 0, sizeof(addr)); 2464 addrlen = sizeof(addr); 2465 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2466 &addrlen)) == -1) { 2467 error_f("accept: %s", strerror(errno)); 2468 if (errno == EMFILE || errno == ENFILE) 2469 c->notbefore = monotime() + 1; 2470 return; 2471 } 2472 2473 if (getpeereid(newsock, &euid, &egid) == -1) { 2474 error_f("getpeereid failed: %s", strerror(errno)); 2475 close(newsock); 2476 return; 2477 } 2478 if ((euid != 0) && (getuid() != euid)) { 2479 error("multiplex uid mismatch: peer euid %u != uid %u", 2480 (u_int)euid, (u_int)getuid()); 2481 close(newsock); 2482 return; 2483 } 2484 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2485 newsock, newsock, -1, c->local_window_max, 2486 c->local_maxpacket, 0, "mux-control", 1); 2487 nc->mux_rcb = c->mux_rcb; 2488 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2489 /* establish state */ 2490 nc->mux_rcb(ssh, nc); 2491 /* mux state transitions must not elicit protocol messages */ 2492 nc->flags |= CHAN_LOCAL; 2493 } 2494 2495 static void 2496 channel_handler_init(struct ssh_channels *sc) 2497 { 2498 chan_fn **pre, **post; 2499 2500 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2501 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2502 fatal_f("allocation failed"); 2503 2504 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2505 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2506 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2507 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2508 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2509 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2510 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2511 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2512 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2513 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2514 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2515 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2516 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2517 2518 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2519 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2520 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2521 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2522 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2523 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2524 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2525 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2526 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2527 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2528 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2529 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2530 2531 sc->channel_pre = pre; 2532 sc->channel_post = post; 2533 } 2534 2535 /* gc dead channels */ 2536 static void 2537 channel_garbage_collect(struct ssh *ssh, Channel *c) 2538 { 2539 if (c == NULL) 2540 return; 2541 if (c->detach_user != NULL) { 2542 if (!chan_is_dead(ssh, c, c->detach_close)) 2543 return; 2544 2545 debug2("channel %d: gc: notify user", c->self); 2546 c->detach_user(ssh, c->self, 0, NULL); 2547 /* if we still have a callback */ 2548 if (c->detach_user != NULL) 2549 return; 2550 debug2("channel %d: gc: user detached", c->self); 2551 } 2552 if (!chan_is_dead(ssh, c, 1)) 2553 return; 2554 debug2("channel %d: garbage collecting", c->self); 2555 channel_free(ssh, c); 2556 } 2557 2558 enum channel_table { CHAN_PRE, CHAN_POST }; 2559 2560 static void 2561 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2562 { 2563 struct ssh_channels *sc = ssh->chanctxt; 2564 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2565 u_int i, oalloc; 2566 Channel *c; 2567 time_t now; 2568 2569 now = monotime(); 2570 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2571 c = sc->channels[i]; 2572 if (c == NULL) 2573 continue; 2574 /* Try to keep IO going while rekeying */ 2575 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2576 continue; 2577 if (c->delayed) { 2578 if (table == CHAN_PRE) 2579 c->delayed = 0; 2580 else 2581 continue; 2582 } 2583 if (ftab[c->type] != NULL) { 2584 if (table == CHAN_PRE && 2585 c->type == SSH_CHANNEL_OPEN && 2586 c->inactive_deadline != 0 && c->lastused != 0 && 2587 now >= c->lastused + c->inactive_deadline) { 2588 /* channel closed for inactivity */ 2589 verbose("channel %d: closing after %u seconds " 2590 "of inactivity", c->self, 2591 c->inactive_deadline); 2592 channel_force_close(ssh, c, 1); 2593 } else if (c->notbefore <= now) { 2594 /* Run handlers that are not paused. */ 2595 (*ftab[c->type])(ssh, c); 2596 /* inactivity timeouts must interrupt poll() */ 2597 if (timeout != NULL && 2598 c->type == SSH_CHANNEL_OPEN && 2599 c->lastused != 0 && 2600 c->inactive_deadline != 0) { 2601 ptimeout_deadline_monotime(timeout, 2602 c->lastused + c->inactive_deadline); 2603 } 2604 } else if (timeout != NULL) { 2605 /* 2606 * Arrange for poll() wakeup when channel pause 2607 * timer expires. 2608 */ 2609 ptimeout_deadline_monotime(timeout, 2610 c->notbefore); 2611 } 2612 } 2613 channel_garbage_collect(ssh, c); 2614 } 2615 } 2616 2617 /* 2618 * Create sockets before preparing IO. 2619 * This is necessary for things that need to happen after reading 2620 * the network-input but need to be completed before IO event setup, e.g. 2621 * because they may create new channels. 2622 */ 2623 static void 2624 channel_before_prepare_io(struct ssh *ssh) 2625 { 2626 struct ssh_channels *sc = ssh->chanctxt; 2627 Channel *c; 2628 u_int i, oalloc; 2629 2630 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2631 c = sc->channels[i]; 2632 if (c == NULL) 2633 continue; 2634 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2635 channel_before_prepare_io_rdynamic(ssh, c); 2636 } 2637 } 2638 2639 static void 2640 dump_channel_poll(const char *func, const char *what, Channel *c, 2641 u_int pollfd_offset, struct pollfd *pfd) 2642 { 2643 #ifdef DEBUG_CHANNEL_POLL 2644 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2645 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2646 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2647 c->rfd, c->wfd, c->efd, c->sock, 2648 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2649 c->io_want, c->io_ready, 2650 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2651 #endif 2652 } 2653 2654 /* Prepare pollfd entries for a single channel */ 2655 static void 2656 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2657 struct pollfd *pfd, u_int npfd) 2658 { 2659 u_int ev, p = *next_pollfd; 2660 2661 if (c == NULL) 2662 return; 2663 if (p + 4 > npfd) { 2664 /* Shouldn't happen */ 2665 fatal_f("channel %d: bad pfd offset %u (max %u)", 2666 c->self, p, npfd); 2667 } 2668 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2669 /* 2670 * prepare c->rfd 2671 * 2672 * This is a special case, since c->rfd might be the same as 2673 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2674 * IO too. 2675 */ 2676 if (c->rfd != -1) { 2677 ev = 0; 2678 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2679 ev |= POLLIN; 2680 /* rfd == wfd */ 2681 if (c->wfd == c->rfd) { 2682 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2683 ev |= POLLOUT; 2684 } 2685 /* rfd == efd */ 2686 if (c->efd == c->rfd) { 2687 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2688 ev |= POLLIN; 2689 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2690 ev |= POLLOUT; 2691 } 2692 /* rfd == sock */ 2693 if (c->sock == c->rfd) { 2694 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2695 ev |= POLLIN; 2696 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2697 ev |= POLLOUT; 2698 } 2699 /* Pack a pfd entry if any event armed for this fd */ 2700 if (ev != 0) { 2701 c->pfds[0] = p; 2702 pfd[p].fd = c->rfd; 2703 pfd[p].events = ev; 2704 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2705 p++; 2706 } 2707 } 2708 /* prepare c->wfd if wanting IO and not already handled above */ 2709 if (c->wfd != -1 && c->rfd != c->wfd) { 2710 ev = 0; 2711 if ((c->io_want & SSH_CHAN_IO_WFD)) 2712 ev |= POLLOUT; 2713 /* Pack a pfd entry if any event armed for this fd */ 2714 if (ev != 0) { 2715 c->pfds[1] = p; 2716 pfd[p].fd = c->wfd; 2717 pfd[p].events = ev; 2718 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2719 p++; 2720 } 2721 } 2722 /* prepare c->efd if wanting IO and not already handled above */ 2723 if (c->efd != -1 && c->rfd != c->efd) { 2724 ev = 0; 2725 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2726 ev |= POLLIN; 2727 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2728 ev |= POLLOUT; 2729 /* Pack a pfd entry if any event armed for this fd */ 2730 if (ev != 0) { 2731 c->pfds[2] = p; 2732 pfd[p].fd = c->efd; 2733 pfd[p].events = ev; 2734 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2735 p++; 2736 } 2737 } 2738 /* prepare c->sock if wanting IO and not already handled above */ 2739 if (c->sock != -1 && c->rfd != c->sock) { 2740 ev = 0; 2741 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2742 ev |= POLLIN; 2743 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2744 ev |= POLLOUT; 2745 /* Pack a pfd entry if any event armed for this fd */ 2746 if (ev != 0) { 2747 c->pfds[3] = p; 2748 pfd[p].fd = c->sock; 2749 pfd[p].events = 0; 2750 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2751 p++; 2752 } 2753 } 2754 *next_pollfd = p; 2755 } 2756 2757 /* * Allocate/prepare poll structure */ 2758 void 2759 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2760 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2761 { 2762 struct ssh_channels *sc = ssh->chanctxt; 2763 u_int i, oalloc, p, npfd = npfd_reserved; 2764 2765 channel_before_prepare_io(ssh); /* might create a new channel */ 2766 /* clear out I/O flags from last poll */ 2767 for (i = 0; i < sc->channels_alloc; i++) { 2768 if (sc->channels[i] == NULL) 2769 continue; 2770 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2771 } 2772 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2773 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2774 fatal_f("too many channels"); /* shouldn't happen */ 2775 npfd += sc->channels_alloc * 4; 2776 if (npfd > *npfd_allocp) { 2777 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2778 npfd, sizeof(**pfdp)); 2779 *npfd_allocp = npfd; 2780 } 2781 *npfd_activep = npfd_reserved; 2782 oalloc = sc->channels_alloc; 2783 2784 channel_handler(ssh, CHAN_PRE, timeout); 2785 2786 if (oalloc != sc->channels_alloc) { 2787 /* shouldn't happen */ 2788 fatal_f("channels_alloc changed during CHAN_PRE " 2789 "(was %u, now %u)", oalloc, sc->channels_alloc); 2790 } 2791 2792 /* Prepare pollfd */ 2793 p = npfd_reserved; 2794 for (i = 0; i < sc->channels_alloc; i++) 2795 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2796 *npfd_activep = p; 2797 } 2798 2799 static void 2800 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2801 const char *what, u_int revents_mask, u_int ready) 2802 { 2803 struct pollfd *pfd = &pfds[p]; 2804 2805 if (fd == -1) 2806 return; 2807 if (p == -1 || (u_int)p >= npfd) 2808 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2809 dump_channel_poll(__func__, what, c, p, pfd); 2810 if (pfd->fd != fd) { 2811 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2812 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2813 c->rfd, c->wfd, c->efd, c->sock); 2814 } 2815 if ((pfd->revents & POLLNVAL) != 0) { 2816 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2817 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2818 } 2819 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2820 c->io_ready |= ready & c->io_want; 2821 } 2822 2823 /* 2824 * After poll, perform any appropriate operations for channels which have 2825 * events pending. 2826 */ 2827 void 2828 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2829 { 2830 struct ssh_channels *sc = ssh->chanctxt; 2831 u_int i; 2832 int p; 2833 Channel *c; 2834 2835 #ifdef DEBUG_CHANNEL_POLL 2836 for (p = 0; p < (int)npfd; p++) { 2837 if (pfd[p].revents == 0) 2838 continue; 2839 debug_f("pfd[%u].fd %d rev 0x%04x", 2840 p, pfd[p].fd, pfd[p].revents); 2841 } 2842 #endif 2843 2844 /* Convert pollfd into c->io_ready */ 2845 for (i = 0; i < sc->channels_alloc; i++) { 2846 c = sc->channels[i]; 2847 if (c == NULL) 2848 continue; 2849 /* if rfd is shared with efd/sock then wfd should be too */ 2850 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2851 (c->rfd == c->efd || c->rfd == c->sock)) { 2852 /* Shouldn't happen */ 2853 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2854 c->self, c->rfd, c->wfd, c->efd, c->sock); 2855 } 2856 c->io_ready = 0; 2857 /* rfd, potentially shared with wfd, efd and sock */ 2858 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2859 fd_ready(c, p, pfd, npfd, c->rfd, 2860 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2861 if (c->rfd == c->wfd) { 2862 fd_ready(c, p, pfd, npfd, c->wfd, 2863 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2864 } 2865 if (c->rfd == c->efd) { 2866 fd_ready(c, p, pfd, npfd, c->efd, 2867 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2868 fd_ready(c, p, pfd, npfd, c->efd, 2869 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2870 } 2871 if (c->rfd == c->sock) { 2872 fd_ready(c, p, pfd, npfd, c->sock, 2873 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2874 fd_ready(c, p, pfd, npfd, c->sock, 2875 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2876 } 2877 dump_channel_poll(__func__, "rfd", c, p, pfd); 2878 } 2879 /* wfd */ 2880 if (c->wfd != -1 && c->wfd != c->rfd && 2881 (p = c->pfds[1]) != -1) { 2882 fd_ready(c, p, pfd, npfd, c->wfd, 2883 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2884 dump_channel_poll(__func__, "wfd", c, p, pfd); 2885 } 2886 /* efd */ 2887 if (c->efd != -1 && c->efd != c->rfd && 2888 (p = c->pfds[2]) != -1) { 2889 fd_ready(c, p, pfd, npfd, c->efd, 2890 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2891 fd_ready(c, p, pfd, npfd, c->efd, 2892 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2893 dump_channel_poll(__func__, "efd", c, p, pfd); 2894 } 2895 /* sock */ 2896 if (c->sock != -1 && c->sock != c->rfd && 2897 (p = c->pfds[3]) != -1) { 2898 fd_ready(c, p, pfd, npfd, c->sock, 2899 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2900 fd_ready(c, p, pfd, npfd, c->sock, 2901 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2902 dump_channel_poll(__func__, "sock", c, p, pfd); 2903 } 2904 } 2905 channel_handler(ssh, CHAN_POST, NULL); 2906 } 2907 2908 /* 2909 * Enqueue data for channels with open or draining c->input. 2910 * Returns non-zero if a packet was enqueued. 2911 */ 2912 static int 2913 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2914 { 2915 size_t len, plen; 2916 const u_char *pkt; 2917 int r; 2918 2919 if ((len = sshbuf_len(c->input)) == 0) { 2920 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2921 /* 2922 * input-buffer is empty and read-socket shutdown: 2923 * tell peer, that we will not send more data: 2924 * send IEOF. 2925 * hack for extended data: delay EOF if EFD still 2926 * in use. 2927 */ 2928 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2929 debug2("channel %d: " 2930 "ibuf_empty delayed efd %d/(%zu)", 2931 c->self, c->efd, sshbuf_len(c->extended)); 2932 else 2933 chan_ibuf_empty(ssh, c); 2934 } 2935 return 0; 2936 } 2937 2938 if (!c->have_remote_id) 2939 fatal_f("channel %d: no remote id", c->self); 2940 2941 if (c->datagram) { 2942 /* Check datagram will fit; drop if not */ 2943 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2944 fatal_fr(r, "channel %i: get datagram", c->self); 2945 /* 2946 * XXX this does tail-drop on the datagram queue which is 2947 * usually suboptimal compared to head-drop. Better to have 2948 * backpressure at read time? (i.e. read + discard) 2949 */ 2950 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2951 debug("channel %d: datagram too big", c->self); 2952 return 0; 2953 } 2954 /* Enqueue it */ 2955 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2956 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2957 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2958 (r = sshpkt_send(ssh)) != 0) 2959 fatal_fr(r, "channel %i: send datagram", c->self); 2960 c->remote_window -= plen; 2961 return 1; 2962 } 2963 2964 /* Enqueue packet for buffered data. */ 2965 if (len > c->remote_window) 2966 len = c->remote_window; 2967 if (len > c->remote_maxpacket) 2968 len = c->remote_maxpacket; 2969 if (len == 0) 2970 return 0; 2971 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2972 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2973 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2974 (r = sshpkt_send(ssh)) != 0) 2975 fatal_fr(r, "channel %i: send data", c->self); 2976 if ((r = sshbuf_consume(c->input, len)) != 0) 2977 fatal_fr(r, "channel %i: consume", c->self); 2978 c->remote_window -= len; 2979 return 1; 2980 } 2981 2982 /* 2983 * Enqueue data for channels with open c->extended in read mode. 2984 * Returns non-zero if a packet was enqueued. 2985 */ 2986 static int 2987 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2988 { 2989 size_t len; 2990 int r; 2991 2992 if ((len = sshbuf_len(c->extended)) == 0) 2993 return 0; 2994 2995 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2996 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2997 if (len > c->remote_window) 2998 len = c->remote_window; 2999 if (len > c->remote_maxpacket) 3000 len = c->remote_maxpacket; 3001 if (len == 0) 3002 return 0; 3003 if (!c->have_remote_id) 3004 fatal_f("channel %d: no remote id", c->self); 3005 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 3006 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3007 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 3008 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 3009 (r = sshpkt_send(ssh)) != 0) 3010 fatal_fr(r, "channel %i: data", c->self); 3011 if ((r = sshbuf_consume(c->extended, len)) != 0) 3012 fatal_fr(r, "channel %i: consume", c->self); 3013 c->remote_window -= len; 3014 debug2("channel %d: sent ext data %zu", c->self, len); 3015 return 1; 3016 } 3017 3018 /* 3019 * If there is data to send to the connection, enqueue some of it now. 3020 * Returns non-zero if data was enqueued. 3021 */ 3022 int 3023 channel_output_poll(struct ssh *ssh) 3024 { 3025 struct ssh_channels *sc = ssh->chanctxt; 3026 Channel *c; 3027 u_int i; 3028 int ret = 0; 3029 3030 for (i = 0; i < sc->channels_alloc; i++) { 3031 c = sc->channels[i]; 3032 if (c == NULL) 3033 continue; 3034 3035 /* 3036 * We are only interested in channels that can have buffered 3037 * incoming data. 3038 */ 3039 if (c->type != SSH_CHANNEL_OPEN) 3040 continue; 3041 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3042 /* XXX is this true? */ 3043 debug3("channel %d: will not send data after close", 3044 c->self); 3045 continue; 3046 } 3047 3048 /* Get the amount of buffered data for this channel. */ 3049 if (c->istate == CHAN_INPUT_OPEN || 3050 c->istate == CHAN_INPUT_WAIT_DRAIN) 3051 ret |= channel_output_poll_input_open(ssh, c); 3052 /* Send extended data, i.e. stderr */ 3053 if (!(c->flags & CHAN_EOF_SENT) && 3054 c->extended_usage == CHAN_EXTENDED_READ) 3055 ret |= channel_output_poll_extended_read(ssh, c); 3056 } 3057 return ret; 3058 } 3059 3060 /* -- mux proxy support */ 3061 3062 /* 3063 * When multiplexing channel messages for mux clients we have to deal 3064 * with downstream messages from the mux client and upstream messages 3065 * from the ssh server: 3066 * 1) Handling downstream messages is straightforward and happens 3067 * in channel_proxy_downstream(): 3068 * - We forward all messages (mostly) unmodified to the server. 3069 * - However, in order to route messages from upstream to the correct 3070 * downstream client, we have to replace the channel IDs used by the 3071 * mux clients with a unique channel ID because the mux clients might 3072 * use conflicting channel IDs. 3073 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3074 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3075 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3076 * with the newly allocated channel ID. 3077 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3078 * channels and processed by channel_proxy_upstream(). The local channel ID 3079 * is then translated back to the original mux client ID. 3080 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3081 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3082 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3083 * downstream mux client are removed. 3084 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3085 * requires more work, because they are not addressed to a specific 3086 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3087 * out whether the request is addressed to the local client or a 3088 * specific downstream client based on the listen-address/port. 3089 * 6) Agent and X11-Forwarding have a similar problem and are currently 3090 * not supported as the matching session/channel cannot be identified 3091 * easily. 3092 */ 3093 3094 /* 3095 * receive packets from downstream mux clients: 3096 * channel callback fired on read from mux client, creates 3097 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3098 * on channel creation. 3099 */ 3100 int 3101 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3102 { 3103 Channel *c = NULL; 3104 struct sshbuf *original = NULL, *modified = NULL; 3105 const u_char *cp; 3106 char *ctype = NULL, *listen_host = NULL; 3107 u_char type; 3108 size_t have; 3109 int ret = -1, r; 3110 u_int id, remote_id, listen_port; 3111 3112 /* sshbuf_dump(downstream->input, stderr); */ 3113 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3114 != 0) { 3115 error_fr(r, "parse"); 3116 return -1; 3117 } 3118 if (have < 2) { 3119 error_f("short message"); 3120 return -1; 3121 } 3122 type = cp[1]; 3123 /* skip padlen + type */ 3124 cp += 2; 3125 have -= 2; 3126 if (ssh_packet_log_type(type)) 3127 debug3_f("channel %u: down->up: type %u", 3128 downstream->self, type); 3129 3130 switch (type) { 3131 case SSH2_MSG_CHANNEL_OPEN: 3132 if ((original = sshbuf_from(cp, have)) == NULL || 3133 (modified = sshbuf_new()) == NULL) { 3134 error_f("alloc"); 3135 goto out; 3136 } 3137 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3138 (r = sshbuf_get_u32(original, &id)) != 0) { 3139 error_fr(r, "parse"); 3140 goto out; 3141 } 3142 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3143 -1, -1, -1, 0, 0, 0, ctype, 1); 3144 c->mux_ctx = downstream; /* point to mux client */ 3145 c->mux_downstream_id = id; /* original downstream id */ 3146 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3147 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3148 (r = sshbuf_putb(modified, original)) != 0) { 3149 error_fr(r, "compose"); 3150 channel_free(ssh, c); 3151 goto out; 3152 } 3153 break; 3154 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3155 /* 3156 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3157 * need to parse 'remote_id' instead of 'ctype'. 3158 */ 3159 if ((original = sshbuf_from(cp, have)) == NULL || 3160 (modified = sshbuf_new()) == NULL) { 3161 error_f("alloc"); 3162 goto out; 3163 } 3164 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3165 (r = sshbuf_get_u32(original, &id)) != 0) { 3166 error_fr(r, "parse"); 3167 goto out; 3168 } 3169 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3170 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3171 c->mux_ctx = downstream; /* point to mux client */ 3172 c->mux_downstream_id = id; 3173 c->remote_id = remote_id; 3174 c->have_remote_id = 1; 3175 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3176 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3177 (r = sshbuf_putb(modified, original)) != 0) { 3178 error_fr(r, "compose"); 3179 channel_free(ssh, c); 3180 goto out; 3181 } 3182 break; 3183 case SSH2_MSG_GLOBAL_REQUEST: 3184 if ((original = sshbuf_from(cp, have)) == NULL) { 3185 error_f("alloc"); 3186 goto out; 3187 } 3188 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3189 error_fr(r, "parse"); 3190 goto out; 3191 } 3192 if (strcmp(ctype, "tcpip-forward") != 0) { 3193 error_f("unsupported request %s", ctype); 3194 goto out; 3195 } 3196 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3197 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3198 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3199 error_fr(r, "parse"); 3200 goto out; 3201 } 3202 if (listen_port > 65535) { 3203 error_f("tcpip-forward for %s: bad port %u", 3204 listen_host, listen_port); 3205 goto out; 3206 } 3207 /* Record that connection to this host/port is permitted. */ 3208 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 3209 listen_host, NULL, (int)listen_port, downstream); 3210 listen_host = NULL; 3211 break; 3212 case SSH2_MSG_CHANNEL_CLOSE: 3213 if (have < 4) 3214 break; 3215 remote_id = PEEK_U32(cp); 3216 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3217 if (c->flags & CHAN_CLOSE_RCVD) 3218 channel_free(ssh, c); 3219 else 3220 c->flags |= CHAN_CLOSE_SENT; 3221 } 3222 break; 3223 } 3224 if (modified) { 3225 if ((r = sshpkt_start(ssh, type)) != 0 || 3226 (r = sshpkt_putb(ssh, modified)) != 0 || 3227 (r = sshpkt_send(ssh)) != 0) { 3228 error_fr(r, "send"); 3229 goto out; 3230 } 3231 } else { 3232 if ((r = sshpkt_start(ssh, type)) != 0 || 3233 (r = sshpkt_put(ssh, cp, have)) != 0 || 3234 (r = sshpkt_send(ssh)) != 0) { 3235 error_fr(r, "send"); 3236 goto out; 3237 } 3238 } 3239 ret = 0; 3240 out: 3241 free(ctype); 3242 free(listen_host); 3243 sshbuf_free(original); 3244 sshbuf_free(modified); 3245 return ret; 3246 } 3247 3248 /* 3249 * receive packets from upstream server and de-multiplex packets 3250 * to correct downstream: 3251 * implemented as a helper for channel input handlers, 3252 * replaces local (proxy) channel ID with downstream channel ID. 3253 */ 3254 int 3255 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3256 { 3257 struct sshbuf *b = NULL; 3258 Channel *downstream; 3259 const u_char *cp = NULL; 3260 size_t len; 3261 int r; 3262 3263 /* 3264 * When receiving packets from the peer we need to check whether we 3265 * need to forward the packets to the mux client. In this case we 3266 * restore the original channel id and keep track of CLOSE messages, 3267 * so we can cleanup the channel. 3268 */ 3269 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3270 return 0; 3271 if ((downstream = c->mux_ctx) == NULL) 3272 return 0; 3273 switch (type) { 3274 case SSH2_MSG_CHANNEL_CLOSE: 3275 case SSH2_MSG_CHANNEL_DATA: 3276 case SSH2_MSG_CHANNEL_EOF: 3277 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3278 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3279 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3280 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3281 case SSH2_MSG_CHANNEL_SUCCESS: 3282 case SSH2_MSG_CHANNEL_FAILURE: 3283 case SSH2_MSG_CHANNEL_REQUEST: 3284 break; 3285 default: 3286 debug2_f("channel %u: unsupported type %u", c->self, type); 3287 return 0; 3288 } 3289 if ((b = sshbuf_new()) == NULL) { 3290 error_f("alloc reply"); 3291 goto out; 3292 } 3293 /* get remaining payload (after id) */ 3294 cp = sshpkt_ptr(ssh, &len); 3295 if (cp == NULL) { 3296 error_f("no packet"); 3297 goto out; 3298 } 3299 /* translate id and send to muxclient */ 3300 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3301 (r = sshbuf_put_u8(b, type)) != 0 || 3302 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3303 (r = sshbuf_put(b, cp, len)) != 0 || 3304 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3305 error_fr(r, "compose muxclient"); 3306 goto out; 3307 } 3308 /* sshbuf_dump(b, stderr); */ 3309 if (ssh_packet_log_type(type)) 3310 debug3_f("channel %u: up->down: type %u", c->self, type); 3311 out: 3312 /* update state */ 3313 switch (type) { 3314 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3315 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3316 if (cp && len > 4) { 3317 c->remote_id = PEEK_U32(cp); 3318 c->have_remote_id = 1; 3319 } 3320 break; 3321 case SSH2_MSG_CHANNEL_CLOSE: 3322 if (c->flags & CHAN_CLOSE_SENT) 3323 channel_free(ssh, c); 3324 else 3325 c->flags |= CHAN_CLOSE_RCVD; 3326 break; 3327 } 3328 sshbuf_free(b); 3329 return 1; 3330 } 3331 3332 /* -- protocol input */ 3333 3334 /* Parse a channel ID from the current packet */ 3335 static int 3336 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3337 { 3338 u_int32_t id; 3339 int r; 3340 3341 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3342 error_r(r, "%s: parse id", where); 3343 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3344 } 3345 if (id > INT_MAX) { 3346 error_r(r, "%s: bad channel id %u", where, id); 3347 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3348 } 3349 return (int)id; 3350 } 3351 3352 /* Lookup a channel from an ID in the current packet */ 3353 static Channel * 3354 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3355 { 3356 int id = channel_parse_id(ssh, where, what); 3357 Channel *c; 3358 3359 if ((c = channel_lookup(ssh, id)) == NULL) { 3360 ssh_packet_disconnect(ssh, 3361 "%s packet referred to nonexistent channel %d", what, id); 3362 } 3363 return c; 3364 } 3365 3366 int 3367 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3368 { 3369 const u_char *data; 3370 size_t data_len, win_len; 3371 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3372 int r; 3373 3374 if (channel_proxy_upstream(c, type, seq, ssh)) 3375 return 0; 3376 3377 /* Ignore any data for non-open channels (might happen on close) */ 3378 if (c->type != SSH_CHANNEL_OPEN && 3379 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3380 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3381 c->type != SSH_CHANNEL_X11_OPEN) 3382 return 0; 3383 3384 /* Get the data. */ 3385 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3386 (r = sshpkt_get_end(ssh)) != 0) 3387 fatal_fr(r, "channel %i: get data", c->self); 3388 3389 win_len = data_len; 3390 if (c->datagram) 3391 win_len += 4; /* string length header */ 3392 3393 /* 3394 * The sending side reduces its window as it sends data, so we 3395 * must 'fake' consumption of the data in order to ensure that window 3396 * updates are sent back. Otherwise the connection might deadlock. 3397 */ 3398 if (c->ostate != CHAN_OUTPUT_OPEN) { 3399 c->local_window -= win_len; 3400 c->local_consumed += win_len; 3401 return 0; 3402 } 3403 3404 if (win_len > c->local_maxpacket) { 3405 logit("channel %d: rcvd big packet %zu, maxpack %u", 3406 c->self, win_len, c->local_maxpacket); 3407 return 0; 3408 } 3409 if (win_len > c->local_window) { 3410 c->local_window_exceeded += win_len - c->local_window; 3411 logit("channel %d: rcvd too much data %zu, win %u/%u " 3412 "(excess %u)", c->self, win_len, c->local_window, 3413 c->local_window_max, c->local_window_exceeded); 3414 c->local_window = 0; 3415 /* Allow 10% grace before bringing the hammer down */ 3416 if (c->local_window_exceeded > (c->local_window_max / 10)) { 3417 ssh_packet_disconnect(ssh, "channel %d: peer ignored " 3418 "channel window", c->self); 3419 } 3420 } else { 3421 c->local_window -= win_len; 3422 c->local_window_exceeded = 0; 3423 } 3424 3425 if (c->datagram) { 3426 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3427 fatal_fr(r, "channel %i: append datagram", c->self); 3428 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3429 fatal_fr(r, "channel %i: append data", c->self); 3430 3431 return 0; 3432 } 3433 3434 int 3435 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3436 { 3437 const u_char *data; 3438 size_t data_len; 3439 u_int32_t tcode; 3440 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3441 int r; 3442 3443 if (channel_proxy_upstream(c, type, seq, ssh)) 3444 return 0; 3445 if (c->type != SSH_CHANNEL_OPEN) { 3446 logit("channel %d: ext data for non open", c->self); 3447 return 0; 3448 } 3449 if (c->flags & CHAN_EOF_RCVD) { 3450 if (ssh->compat & SSH_BUG_EXTEOF) 3451 debug("channel %d: accepting ext data after eof", 3452 c->self); 3453 else 3454 ssh_packet_disconnect(ssh, "Received extended_data " 3455 "after EOF on channel %d.", c->self); 3456 } 3457 3458 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3459 error_fr(r, "parse tcode"); 3460 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3461 } 3462 if (c->efd == -1 || 3463 c->extended_usage != CHAN_EXTENDED_WRITE || 3464 tcode != SSH2_EXTENDED_DATA_STDERR) { 3465 logit("channel %d: bad ext data", c->self); 3466 return 0; 3467 } 3468 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3469 (r = sshpkt_get_end(ssh)) != 0) { 3470 error_fr(r, "parse data"); 3471 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3472 } 3473 3474 if (data_len > c->local_window) { 3475 logit("channel %d: rcvd too much extended_data %zu, win %u", 3476 c->self, data_len, c->local_window); 3477 return 0; 3478 } 3479 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3480 /* XXX sshpkt_getb? */ 3481 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3482 error_fr(r, "append"); 3483 c->local_window -= data_len; 3484 return 0; 3485 } 3486 3487 int 3488 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3489 { 3490 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3491 int r; 3492 3493 if ((r = sshpkt_get_end(ssh)) != 0) { 3494 error_fr(r, "parse data"); 3495 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3496 } 3497 3498 if (channel_proxy_upstream(c, type, seq, ssh)) 3499 return 0; 3500 chan_rcvd_ieof(ssh, c); 3501 3502 /* XXX force input close */ 3503 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3504 debug("channel %d: FORCE input drain", c->self); 3505 c->istate = CHAN_INPUT_WAIT_DRAIN; 3506 if (sshbuf_len(c->input) == 0) 3507 chan_ibuf_empty(ssh, c); 3508 } 3509 return 0; 3510 } 3511 3512 int 3513 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3514 { 3515 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3516 int r; 3517 3518 if (channel_proxy_upstream(c, type, seq, ssh)) 3519 return 0; 3520 if ((r = sshpkt_get_end(ssh)) != 0) { 3521 error_fr(r, "parse data"); 3522 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3523 } 3524 chan_rcvd_oclose(ssh, c); 3525 return 0; 3526 } 3527 3528 int 3529 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3530 { 3531 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3532 u_int32_t remote_window, remote_maxpacket; 3533 int r; 3534 3535 if (channel_proxy_upstream(c, type, seq, ssh)) 3536 return 0; 3537 if (c->type != SSH_CHANNEL_OPENING) 3538 ssh_packet_disconnect(ssh, "Received open confirmation for " 3539 "non-opening channel %d.", c->self); 3540 /* 3541 * Record the remote channel number and mark that the channel 3542 * is now open. 3543 */ 3544 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3545 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3546 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3547 (r = sshpkt_get_end(ssh)) != 0) { 3548 error_fr(r, "window/maxpacket"); 3549 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3550 } 3551 3552 c->have_remote_id = 1; 3553 c->remote_window = remote_window; 3554 c->remote_maxpacket = remote_maxpacket; 3555 c->type = SSH_CHANNEL_OPEN; 3556 if (c->open_confirm) { 3557 debug2_f("channel %d: callback start", c->self); 3558 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3559 debug2_f("channel %d: callback done", c->self); 3560 } 3561 c->lastused = monotime(); 3562 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3563 c->remote_window, c->remote_maxpacket); 3564 return 0; 3565 } 3566 3567 static char * 3568 reason2txt(int reason) 3569 { 3570 switch (reason) { 3571 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3572 return "administratively prohibited"; 3573 case SSH2_OPEN_CONNECT_FAILED: 3574 return "connect failed"; 3575 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3576 return "unknown channel type"; 3577 case SSH2_OPEN_RESOURCE_SHORTAGE: 3578 return "resource shortage"; 3579 } 3580 return "unknown reason"; 3581 } 3582 3583 int 3584 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3585 { 3586 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3587 u_int32_t reason; 3588 char *msg = NULL; 3589 int r; 3590 3591 if (channel_proxy_upstream(c, type, seq, ssh)) 3592 return 0; 3593 if (c->type != SSH_CHANNEL_OPENING) 3594 ssh_packet_disconnect(ssh, "Received open failure for " 3595 "non-opening channel %d.", c->self); 3596 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3597 error_fr(r, "parse reason"); 3598 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3599 } 3600 /* skip language */ 3601 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3602 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3603 (r = sshpkt_get_end(ssh)) != 0) { 3604 error_fr(r, "parse msg/lang"); 3605 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3606 } 3607 logit("channel %d: open failed: %s%s%s", c->self, 3608 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3609 free(msg); 3610 if (c->open_confirm) { 3611 debug2_f("channel %d: callback start", c->self); 3612 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3613 debug2_f("channel %d: callback done", c->self); 3614 } 3615 /* Schedule the channel for cleanup/deletion. */ 3616 chan_mark_dead(ssh, c); 3617 return 0; 3618 } 3619 3620 int 3621 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3622 { 3623 int id = channel_parse_id(ssh, __func__, "window adjust"); 3624 Channel *c; 3625 u_int32_t adjust; 3626 u_int new_rwin; 3627 int r; 3628 3629 if ((c = channel_lookup(ssh, id)) == NULL) { 3630 logit("Received window adjust for non-open channel %d.", id); 3631 return 0; 3632 } 3633 3634 if (channel_proxy_upstream(c, type, seq, ssh)) 3635 return 0; 3636 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3637 (r = sshpkt_get_end(ssh)) != 0) { 3638 error_fr(r, "parse adjust"); 3639 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3640 } 3641 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3642 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3643 fatal("channel %d: adjust %u overflows remote window %u", 3644 c->self, adjust, c->remote_window); 3645 } 3646 c->remote_window = new_rwin; 3647 return 0; 3648 } 3649 3650 int 3651 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3652 { 3653 int id = channel_parse_id(ssh, __func__, "status confirm"); 3654 Channel *c; 3655 struct channel_confirm *cc; 3656 3657 /* Reset keepalive timeout */ 3658 ssh_packet_set_alive_timeouts(ssh, 0); 3659 3660 debug2_f("type %d id %d", type, id); 3661 3662 if ((c = channel_lookup(ssh, id)) == NULL) { 3663 logit_f("%d: unknown", id); 3664 return 0; 3665 } 3666 if (channel_proxy_upstream(c, type, seq, ssh)) 3667 return 0; 3668 if (sshpkt_get_end(ssh) != 0) 3669 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3670 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3671 return 0; 3672 cc->cb(ssh, type, c, cc->ctx); 3673 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3674 freezero(cc, sizeof(*cc)); 3675 return 0; 3676 } 3677 3678 /* -- tcp forwarding */ 3679 3680 void 3681 channel_set_af(struct ssh *ssh, int af) 3682 { 3683 ssh->chanctxt->IPv4or6 = af; 3684 } 3685 3686 3687 /* 3688 * Determine whether or not a port forward listens to loopback, the 3689 * specified address or wildcard. On the client, a specified bind 3690 * address will always override gateway_ports. On the server, a 3691 * gateway_ports of 1 (``yes'') will override the client's specification 3692 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3693 * will bind to whatever address the client asked for. 3694 * 3695 * Special-case listen_addrs are: 3696 * 3697 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3698 * "" (empty string), "*" -> wildcard v4/v6 3699 * "localhost" -> loopback v4/v6 3700 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3701 */ 3702 static const char * 3703 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3704 int is_client, struct ForwardOptions *fwd_opts) 3705 { 3706 const char *addr = NULL; 3707 int wildcard = 0; 3708 3709 if (listen_addr == NULL) { 3710 /* No address specified: default to gateway_ports setting */ 3711 if (fwd_opts->gateway_ports) 3712 wildcard = 1; 3713 } else if (fwd_opts->gateway_ports || is_client) { 3714 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3715 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3716 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3717 (!is_client && fwd_opts->gateway_ports == 1)) { 3718 wildcard = 1; 3719 /* 3720 * Notify client if they requested a specific listen 3721 * address and it was overridden. 3722 */ 3723 if (*listen_addr != '\0' && 3724 strcmp(listen_addr, "0.0.0.0") != 0 && 3725 strcmp(listen_addr, "*") != 0) { 3726 ssh_packet_send_debug(ssh, 3727 "Forwarding listen address " 3728 "\"%s\" overridden by server " 3729 "GatewayPorts", listen_addr); 3730 } 3731 } else if (strcmp(listen_addr, "localhost") != 0 || 3732 strcmp(listen_addr, "127.0.0.1") == 0 || 3733 strcmp(listen_addr, "::1") == 0) { 3734 /* 3735 * Accept explicit localhost address when 3736 * GatewayPorts=yes. The "localhost" hostname is 3737 * deliberately skipped here so it will listen on all 3738 * available local address families. 3739 */ 3740 addr = listen_addr; 3741 } 3742 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3743 strcmp(listen_addr, "::1") == 0) { 3744 /* 3745 * If a specific IPv4/IPv6 localhost address has been 3746 * requested then accept it even if gateway_ports is in 3747 * effect. This allows the client to prefer IPv4 or IPv6. 3748 */ 3749 addr = listen_addr; 3750 } 3751 if (wildcardp != NULL) 3752 *wildcardp = wildcard; 3753 return addr; 3754 } 3755 3756 static int 3757 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3758 struct Forward *fwd, int *allocated_listen_port, 3759 struct ForwardOptions *fwd_opts) 3760 { 3761 Channel *c; 3762 int sock, r, success = 0, wildcard = 0, is_client; 3763 struct addrinfo hints, *ai, *aitop; 3764 const char *host, *addr; 3765 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3766 in_port_t *lport_p; 3767 3768 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3769 3770 if (is_client && fwd->connect_path != NULL) { 3771 host = fwd->connect_path; 3772 } else { 3773 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3774 fwd->listen_host : fwd->connect_host; 3775 if (host == NULL) { 3776 error("No forward host name."); 3777 return 0; 3778 } 3779 if (strlen(host) >= NI_MAXHOST) { 3780 error("Forward host name too long."); 3781 return 0; 3782 } 3783 } 3784 3785 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3786 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3787 is_client, fwd_opts); 3788 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3789 (addr == NULL) ? "NULL" : addr); 3790 3791 /* 3792 * getaddrinfo returns a loopback address if the hostname is 3793 * set to NULL and hints.ai_flags is not AI_PASSIVE 3794 */ 3795 memset(&hints, 0, sizeof(hints)); 3796 hints.ai_family = ssh->chanctxt->IPv4or6; 3797 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3798 hints.ai_socktype = SOCK_STREAM; 3799 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3800 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3801 if (addr == NULL) { 3802 /* This really shouldn't happen */ 3803 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3804 ssh_gai_strerror(r)); 3805 } else { 3806 error_f("getaddrinfo(%.64s): %s", addr, 3807 ssh_gai_strerror(r)); 3808 } 3809 return 0; 3810 } 3811 if (allocated_listen_port != NULL) 3812 *allocated_listen_port = 0; 3813 for (ai = aitop; ai; ai = ai->ai_next) { 3814 switch (ai->ai_family) { 3815 case AF_INET: 3816 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3817 sin_port; 3818 break; 3819 case AF_INET6: 3820 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3821 sin6_port; 3822 break; 3823 default: 3824 continue; 3825 } 3826 /* 3827 * If allocating a port for -R forwards, then use the 3828 * same port for all address families. 3829 */ 3830 if (type == SSH_CHANNEL_RPORT_LISTENER && 3831 fwd->listen_port == 0 && allocated_listen_port != NULL && 3832 *allocated_listen_port > 0) 3833 *lport_p = htons(*allocated_listen_port); 3834 3835 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3836 strport, sizeof(strport), 3837 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3838 error_f("getnameinfo failed"); 3839 continue; 3840 } 3841 /* Create a port to listen for the host. */ 3842 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3843 if (sock == -1) { 3844 /* this is no error since kernel may not support ipv6 */ 3845 verbose("socket [%s]:%s: %.100s", ntop, strport, 3846 strerror(errno)); 3847 continue; 3848 } 3849 3850 set_reuseaddr(sock); 3851 if (ai->ai_family == AF_INET6) 3852 sock_set_v6only(sock); 3853 3854 debug("Local forwarding listening on %s port %s.", 3855 ntop, strport); 3856 3857 /* Bind the socket to the address. */ 3858 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3859 /* 3860 * address can be in if use ipv6 address is 3861 * already bound 3862 */ 3863 if (!ai->ai_next) 3864 error("bind [%s]:%s: %.100s", 3865 ntop, strport, strerror(errno)); 3866 else 3867 verbose("bind [%s]:%s: %.100s", 3868 ntop, strport, strerror(errno)); 3869 3870 close(sock); 3871 continue; 3872 } 3873 /* Start listening for connections on the socket. */ 3874 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3875 error("listen [%s]:%s: %.100s", ntop, strport, 3876 strerror(errno)); 3877 close(sock); 3878 continue; 3879 } 3880 3881 /* 3882 * fwd->listen_port == 0 requests a dynamically allocated port - 3883 * record what we got. 3884 */ 3885 if (type == SSH_CHANNEL_RPORT_LISTENER && 3886 fwd->listen_port == 0 && 3887 allocated_listen_port != NULL && 3888 *allocated_listen_port == 0) { 3889 *allocated_listen_port = get_local_port(sock); 3890 debug("Allocated listen port %d", 3891 *allocated_listen_port); 3892 } 3893 3894 /* Allocate a channel number for the socket. */ 3895 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 3896 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3897 0, "port listener", 1); 3898 c->path = xstrdup(host); 3899 c->host_port = fwd->connect_port; 3900 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3901 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3902 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3903 c->listening_port = *allocated_listen_port; 3904 else 3905 c->listening_port = fwd->listen_port; 3906 success = 1; 3907 } 3908 if (success == 0) 3909 error_f("cannot listen to port: %d", fwd->listen_port); 3910 freeaddrinfo(aitop); 3911 return success; 3912 } 3913 3914 static int 3915 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3916 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3917 { 3918 struct sockaddr_un sunaddr; 3919 const char *path; 3920 Channel *c; 3921 int port, sock; 3922 mode_t omask; 3923 3924 switch (type) { 3925 case SSH_CHANNEL_UNIX_LISTENER: 3926 if (fwd->connect_path != NULL) { 3927 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3928 error("Local connecting path too long: %s", 3929 fwd->connect_path); 3930 return 0; 3931 } 3932 path = fwd->connect_path; 3933 port = PORT_STREAMLOCAL; 3934 } else { 3935 if (fwd->connect_host == NULL) { 3936 error("No forward host name."); 3937 return 0; 3938 } 3939 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3940 error("Forward host name too long."); 3941 return 0; 3942 } 3943 path = fwd->connect_host; 3944 port = fwd->connect_port; 3945 } 3946 break; 3947 case SSH_CHANNEL_RUNIX_LISTENER: 3948 path = fwd->listen_path; 3949 port = PORT_STREAMLOCAL; 3950 break; 3951 default: 3952 error_f("unexpected channel type %d", type); 3953 return 0; 3954 } 3955 3956 if (fwd->listen_path == NULL) { 3957 error("No forward path name."); 3958 return 0; 3959 } 3960 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3961 error("Local listening path too long: %s", fwd->listen_path); 3962 return 0; 3963 } 3964 3965 debug3_f("type %d path %s", type, fwd->listen_path); 3966 3967 /* Start a Unix domain listener. */ 3968 omask = umask(fwd_opts->streamlocal_bind_mask); 3969 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3970 fwd_opts->streamlocal_bind_unlink); 3971 umask(omask); 3972 if (sock < 0) 3973 return 0; 3974 3975 debug("Local forwarding listening on path %s.", fwd->listen_path); 3976 3977 /* Allocate a channel number for the socket. */ 3978 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 3979 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3980 0, "unix listener", 1); 3981 c->path = xstrdup(path); 3982 c->host_port = port; 3983 c->listening_port = PORT_STREAMLOCAL; 3984 c->listening_addr = xstrdup(fwd->listen_path); 3985 return 1; 3986 } 3987 3988 static int 3989 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3990 const char *host, u_short port) 3991 { 3992 u_int i; 3993 int found = 0; 3994 3995 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3996 Channel *c = ssh->chanctxt->channels[i]; 3997 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3998 continue; 3999 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 4000 debug2_f("close channel %d", i); 4001 channel_free(ssh, c); 4002 found = 1; 4003 } 4004 } 4005 4006 return found; 4007 } 4008 4009 static int 4010 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 4011 { 4012 u_int i; 4013 int found = 0; 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_RUNIX_LISTENER) 4018 continue; 4019 if (c->path == NULL) 4020 continue; 4021 if (strcmp(c->path, 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_rport_listener(struct ssh *ssh, struct Forward *fwd) 4033 { 4034 if (fwd->listen_path != NULL) { 4035 return channel_cancel_rport_listener_streamlocal(ssh, 4036 fwd->listen_path); 4037 } else { 4038 return channel_cancel_rport_listener_tcpip(ssh, 4039 fwd->listen_host, fwd->listen_port); 4040 } 4041 } 4042 4043 static int 4044 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4045 const char *lhost, u_short lport, int cport, 4046 struct ForwardOptions *fwd_opts) 4047 { 4048 u_int i; 4049 int found = 0; 4050 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4051 4052 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4053 Channel *c = ssh->chanctxt->channels[i]; 4054 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4055 continue; 4056 if (c->listening_port != lport) 4057 continue; 4058 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4059 /* skip dynamic forwardings */ 4060 if (c->host_port == 0) 4061 continue; 4062 } else { 4063 if (c->host_port != cport) 4064 continue; 4065 } 4066 if ((c->listening_addr == NULL && addr != NULL) || 4067 (c->listening_addr != NULL && addr == NULL)) 4068 continue; 4069 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4070 debug2_f("close channel %d", i); 4071 channel_free(ssh, c); 4072 found = 1; 4073 } 4074 } 4075 4076 return found; 4077 } 4078 4079 static int 4080 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4081 { 4082 u_int i; 4083 int found = 0; 4084 4085 if (path == NULL) { 4086 error_f("no path specified."); 4087 return 0; 4088 } 4089 4090 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4091 Channel *c = ssh->chanctxt->channels[i]; 4092 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4093 continue; 4094 if (c->listening_addr == NULL) 4095 continue; 4096 if (strcmp(c->listening_addr, path) == 0) { 4097 debug2_f("close channel %d", i); 4098 channel_free(ssh, c); 4099 found = 1; 4100 } 4101 } 4102 4103 return found; 4104 } 4105 4106 int 4107 channel_cancel_lport_listener(struct ssh *ssh, 4108 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4109 { 4110 if (fwd->listen_path != NULL) { 4111 return channel_cancel_lport_listener_streamlocal(ssh, 4112 fwd->listen_path); 4113 } else { 4114 return channel_cancel_lport_listener_tcpip(ssh, 4115 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4116 } 4117 } 4118 4119 /* protocol local port fwd, used by ssh */ 4120 int 4121 channel_setup_local_fwd_listener(struct ssh *ssh, 4122 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4123 { 4124 if (fwd->listen_path != NULL) { 4125 return channel_setup_fwd_listener_streamlocal(ssh, 4126 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4127 } else { 4128 return channel_setup_fwd_listener_tcpip(ssh, 4129 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4130 } 4131 } 4132 4133 /* Matches a remote forwarding permission against a requested forwarding */ 4134 static int 4135 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4136 { 4137 int ret; 4138 char *lhost; 4139 4140 /* XXX add ACLs for streamlocal */ 4141 if (fwd->listen_path != NULL) 4142 return 1; 4143 4144 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4145 return 0; 4146 4147 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4148 allowed_open->listen_port != fwd->listen_port) 4149 return 0; 4150 4151 /* Match hostnames case-insensitively */ 4152 lhost = xstrdup(fwd->listen_host); 4153 lowercase(lhost); 4154 ret = match_pattern(lhost, allowed_open->listen_host); 4155 free(lhost); 4156 4157 return ret; 4158 } 4159 4160 /* Checks whether a requested remote forwarding is permitted */ 4161 static int 4162 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4163 { 4164 struct ssh_channels *sc = ssh->chanctxt; 4165 struct permission_set *pset = &sc->remote_perms; 4166 u_int i, permit, permit_adm = 1; 4167 struct permission *perm; 4168 4169 /* XXX apply GatewayPorts override before checking? */ 4170 4171 permit = pset->all_permitted; 4172 if (!permit) { 4173 for (i = 0; i < pset->num_permitted_user; i++) { 4174 perm = &pset->permitted_user[i]; 4175 if (remote_open_match(perm, fwd)) { 4176 permit = 1; 4177 break; 4178 } 4179 } 4180 } 4181 4182 if (pset->num_permitted_admin > 0) { 4183 permit_adm = 0; 4184 for (i = 0; i < pset->num_permitted_admin; i++) { 4185 perm = &pset->permitted_admin[i]; 4186 if (remote_open_match(perm, fwd)) { 4187 permit_adm = 1; 4188 break; 4189 } 4190 } 4191 } 4192 4193 return permit && permit_adm; 4194 } 4195 4196 /* protocol v2 remote port fwd, used by sshd */ 4197 int 4198 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4199 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4200 { 4201 if (!check_rfwd_permission(ssh, fwd)) { 4202 ssh_packet_send_debug(ssh, "port forwarding refused"); 4203 if (fwd->listen_path != NULL) 4204 /* XXX always allowed, see remote_open_match() */ 4205 logit("Received request from %.100s port %d to " 4206 "remote forward to path \"%.100s\", " 4207 "but the request was denied.", 4208 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4209 fwd->listen_path); 4210 else if(fwd->listen_host != NULL) 4211 logit("Received request from %.100s port %d to " 4212 "remote forward to host %.100s port %d, " 4213 "but the request was denied.", 4214 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4215 fwd->listen_host, fwd->listen_port ); 4216 else 4217 logit("Received request from %.100s port %d to remote " 4218 "forward, but the request was denied.", 4219 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4220 return 0; 4221 } 4222 if (fwd->listen_path != NULL) { 4223 return channel_setup_fwd_listener_streamlocal(ssh, 4224 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4225 } else { 4226 return channel_setup_fwd_listener_tcpip(ssh, 4227 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4228 fwd_opts); 4229 } 4230 } 4231 4232 /* 4233 * Translate the requested rfwd listen host to something usable for 4234 * this server. 4235 */ 4236 static const char * 4237 channel_rfwd_bind_host(const char *listen_host) 4238 { 4239 if (listen_host == NULL) { 4240 return "localhost"; 4241 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4242 return ""; 4243 } else 4244 return listen_host; 4245 } 4246 4247 /* 4248 * Initiate forwarding of connections to port "port" on remote host through 4249 * the secure channel to host:port from local side. 4250 * Returns handle (index) for updating the dynamic listen port with 4251 * channel_update_permission(). 4252 */ 4253 int 4254 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4255 { 4256 int r, success = 0, idx = -1; 4257 const char *host_to_connect, *listen_host, *listen_path; 4258 int port_to_connect, listen_port; 4259 4260 /* Send the forward request to the remote side. */ 4261 if (fwd->listen_path != NULL) { 4262 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4263 (r = sshpkt_put_cstring(ssh, 4264 "streamlocal-forward@openssh.com")) != 0 || 4265 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4266 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4267 (r = sshpkt_send(ssh)) != 0 || 4268 (r = ssh_packet_write_wait(ssh)) != 0) 4269 fatal_fr(r, "request streamlocal"); 4270 } else { 4271 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4272 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4273 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4274 (r = sshpkt_put_cstring(ssh, 4275 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4276 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4277 (r = sshpkt_send(ssh)) != 0 || 4278 (r = ssh_packet_write_wait(ssh)) != 0) 4279 fatal_fr(r, "request tcpip-forward"); 4280 } 4281 /* Assume that server accepts the request */ 4282 success = 1; 4283 if (success) { 4284 /* Record that connection to this host/port is permitted. */ 4285 host_to_connect = listen_host = listen_path = NULL; 4286 port_to_connect = listen_port = 0; 4287 if (fwd->connect_path != NULL) { 4288 host_to_connect = fwd->connect_path; 4289 port_to_connect = PORT_STREAMLOCAL; 4290 } else { 4291 host_to_connect = fwd->connect_host; 4292 port_to_connect = fwd->connect_port; 4293 } 4294 if (fwd->listen_path != NULL) { 4295 listen_path = fwd->listen_path; 4296 listen_port = PORT_STREAMLOCAL; 4297 } else { 4298 listen_host = fwd->listen_host; 4299 listen_port = fwd->listen_port; 4300 } 4301 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4302 host_to_connect, port_to_connect, 4303 listen_host, listen_path, listen_port, NULL); 4304 } 4305 return idx; 4306 } 4307 4308 static int 4309 open_match(struct permission *allowed_open, const char *requestedhost, 4310 int requestedport) 4311 { 4312 if (allowed_open->host_to_connect == NULL) 4313 return 0; 4314 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4315 allowed_open->port_to_connect != requestedport) 4316 return 0; 4317 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4318 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4319 return 0; 4320 return 1; 4321 } 4322 4323 /* 4324 * Note that in the listen host/port case 4325 * we don't support FWD_PERMIT_ANY_PORT and 4326 * need to translate between the configured-host (listen_host) 4327 * and what we've sent to the remote server (channel_rfwd_bind_host) 4328 */ 4329 static int 4330 open_listen_match_tcpip(struct permission *allowed_open, 4331 const char *requestedhost, u_short requestedport, int translate) 4332 { 4333 const char *allowed_host; 4334 4335 if (allowed_open->host_to_connect == NULL) 4336 return 0; 4337 if (allowed_open->listen_port != requestedport) 4338 return 0; 4339 if (!translate && allowed_open->listen_host == NULL && 4340 requestedhost == NULL) 4341 return 1; 4342 allowed_host = translate ? 4343 channel_rfwd_bind_host(allowed_open->listen_host) : 4344 allowed_open->listen_host; 4345 if (allowed_host == NULL || requestedhost == NULL || 4346 strcmp(allowed_host, requestedhost) != 0) 4347 return 0; 4348 return 1; 4349 } 4350 4351 static int 4352 open_listen_match_streamlocal(struct permission *allowed_open, 4353 const char *requestedpath) 4354 { 4355 if (allowed_open->host_to_connect == NULL) 4356 return 0; 4357 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4358 return 0; 4359 if (allowed_open->listen_path == NULL || 4360 strcmp(allowed_open->listen_path, requestedpath) != 0) 4361 return 0; 4362 return 1; 4363 } 4364 4365 /* 4366 * Request cancellation of remote forwarding of connection host:port from 4367 * local side. 4368 */ 4369 static int 4370 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4371 const char *host, u_short port) 4372 { 4373 struct ssh_channels *sc = ssh->chanctxt; 4374 struct permission_set *pset = &sc->local_perms; 4375 int r; 4376 u_int i; 4377 struct permission *perm = NULL; 4378 4379 for (i = 0; i < pset->num_permitted_user; i++) { 4380 perm = &pset->permitted_user[i]; 4381 if (open_listen_match_tcpip(perm, host, port, 0)) 4382 break; 4383 perm = NULL; 4384 } 4385 if (perm == NULL) { 4386 debug_f("requested forward not found"); 4387 return -1; 4388 } 4389 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4390 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4391 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4392 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4393 (r = sshpkt_put_u32(ssh, port)) != 0 || 4394 (r = sshpkt_send(ssh)) != 0) 4395 fatal_fr(r, "send cancel"); 4396 4397 fwd_perm_clear(perm); /* unregister */ 4398 4399 return 0; 4400 } 4401 4402 /* 4403 * Request cancellation of remote forwarding of Unix domain socket 4404 * path from local side. 4405 */ 4406 static int 4407 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4408 { 4409 struct ssh_channels *sc = ssh->chanctxt; 4410 struct permission_set *pset = &sc->local_perms; 4411 int r; 4412 u_int i; 4413 struct permission *perm = NULL; 4414 4415 for (i = 0; i < pset->num_permitted_user; i++) { 4416 perm = &pset->permitted_user[i]; 4417 if (open_listen_match_streamlocal(perm, path)) 4418 break; 4419 perm = NULL; 4420 } 4421 if (perm == NULL) { 4422 debug_f("requested forward not found"); 4423 return -1; 4424 } 4425 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4426 (r = sshpkt_put_cstring(ssh, 4427 "cancel-streamlocal-forward@openssh.com")) != 0 || 4428 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4429 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4430 (r = sshpkt_send(ssh)) != 0) 4431 fatal_fr(r, "send cancel"); 4432 4433 fwd_perm_clear(perm); /* unregister */ 4434 4435 return 0; 4436 } 4437 4438 /* 4439 * Request cancellation of remote forwarding of a connection from local side. 4440 */ 4441 int 4442 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4443 { 4444 if (fwd->listen_path != NULL) { 4445 return channel_request_rforward_cancel_streamlocal(ssh, 4446 fwd->listen_path); 4447 } else { 4448 return channel_request_rforward_cancel_tcpip(ssh, 4449 fwd->listen_host, 4450 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4451 } 4452 } 4453 4454 /* 4455 * Permits opening to any host/port if permitted_user[] is empty. This is 4456 * usually called by the server, because the user could connect to any port 4457 * anyway, and the server has no way to know but to trust the client anyway. 4458 */ 4459 void 4460 channel_permit_all(struct ssh *ssh, int where) 4461 { 4462 struct permission_set *pset = permission_set_get(ssh, where); 4463 4464 if (pset->num_permitted_user == 0) 4465 pset->all_permitted = 1; 4466 } 4467 4468 /* 4469 * Permit the specified host/port for forwarding. 4470 */ 4471 void 4472 channel_add_permission(struct ssh *ssh, int who, int where, 4473 char *host, int port) 4474 { 4475 int local = where == FORWARD_LOCAL; 4476 struct permission_set *pset = permission_set_get(ssh, where); 4477 4478 debug("allow %s forwarding to host %s port %d", 4479 fwd_ident(who, where), host, port); 4480 /* 4481 * Remote forwards set listen_host/port, local forwards set 4482 * host/port_to_connect. 4483 */ 4484 permission_set_add(ssh, who, where, 4485 local ? host : 0, local ? port : 0, 4486 local ? NULL : host, NULL, local ? 0 : port, NULL); 4487 pset->all_permitted = 0; 4488 } 4489 4490 /* 4491 * Administratively disable forwarding. 4492 */ 4493 void 4494 channel_disable_admin(struct ssh *ssh, int where) 4495 { 4496 channel_clear_permission(ssh, FORWARD_ADM, where); 4497 permission_set_add(ssh, FORWARD_ADM, where, 4498 NULL, 0, NULL, NULL, 0, NULL); 4499 } 4500 4501 /* 4502 * Clear a list of permitted opens. 4503 */ 4504 void 4505 channel_clear_permission(struct ssh *ssh, int who, int where) 4506 { 4507 struct permission **permp; 4508 u_int *npermp; 4509 4510 permission_set_get_array(ssh, who, where, &permp, &npermp); 4511 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4512 *npermp = 0; 4513 } 4514 4515 /* 4516 * Update the listen port for a dynamic remote forward, after 4517 * the actual 'newport' has been allocated. If 'newport' < 0 is 4518 * passed then they entry will be invalidated. 4519 */ 4520 void 4521 channel_update_permission(struct ssh *ssh, int idx, int newport) 4522 { 4523 struct permission_set *pset = &ssh->chanctxt->local_perms; 4524 4525 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4526 debug_f("index out of range: %d num_permitted_user %d", 4527 idx, pset->num_permitted_user); 4528 return; 4529 } 4530 debug("%s allowed port %d for forwarding to host %s port %d", 4531 newport > 0 ? "Updating" : "Removing", 4532 newport, 4533 pset->permitted_user[idx].host_to_connect, 4534 pset->permitted_user[idx].port_to_connect); 4535 if (newport <= 0) 4536 fwd_perm_clear(&pset->permitted_user[idx]); 4537 else { 4538 pset->permitted_user[idx].listen_port = 4539 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4540 } 4541 } 4542 4543 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4544 int 4545 permitopen_port(const char *p) 4546 { 4547 int port; 4548 4549 if (strcmp(p, "*") == 0) 4550 return FWD_PERMIT_ANY_PORT; 4551 if ((port = a2port(p)) > 0) 4552 return port; 4553 return -1; 4554 } 4555 4556 /* Try to start non-blocking connect to next host in cctx list */ 4557 static int 4558 connect_next(struct channel_connect *cctx) 4559 { 4560 int sock, saved_errno; 4561 struct sockaddr_un *sunaddr; 4562 char ntop[NI_MAXHOST]; 4563 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4564 4565 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4566 switch (cctx->ai->ai_family) { 4567 case AF_UNIX: 4568 /* unix:pathname instead of host:port */ 4569 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4570 strlcpy(ntop, "unix", sizeof(ntop)); 4571 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4572 break; 4573 case AF_INET: 4574 case AF_INET6: 4575 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4576 ntop, sizeof(ntop), strport, sizeof(strport), 4577 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4578 error_f("getnameinfo failed"); 4579 continue; 4580 } 4581 break; 4582 default: 4583 continue; 4584 } 4585 debug_f("start for host %.100s ([%.100s]:%s)", 4586 cctx->host, ntop, strport); 4587 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4588 cctx->ai->ai_protocol)) == -1) { 4589 if (cctx->ai->ai_next == NULL) 4590 error("socket: %.100s", strerror(errno)); 4591 else 4592 verbose("socket: %.100s", strerror(errno)); 4593 continue; 4594 } 4595 if (set_nonblock(sock) == -1) 4596 fatal_f("set_nonblock(%d)", sock); 4597 if (connect(sock, cctx->ai->ai_addr, 4598 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4599 debug_f("host %.100s ([%.100s]:%s): %.100s", 4600 cctx->host, ntop, strport, strerror(errno)); 4601 saved_errno = errno; 4602 close(sock); 4603 errno = saved_errno; 4604 continue; /* fail -- try next */ 4605 } 4606 if (cctx->ai->ai_family != AF_UNIX) 4607 set_nodelay(sock); 4608 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4609 cctx->host, ntop, strport, sock); 4610 cctx->ai = cctx->ai->ai_next; 4611 return sock; 4612 } 4613 return -1; 4614 } 4615 4616 static void 4617 channel_connect_ctx_free(struct channel_connect *cctx) 4618 { 4619 free(cctx->host); 4620 if (cctx->aitop) { 4621 if (cctx->aitop->ai_family == AF_UNIX) 4622 free(cctx->aitop); 4623 else 4624 freeaddrinfo(cctx->aitop); 4625 } 4626 memset(cctx, 0, sizeof(*cctx)); 4627 } 4628 4629 /* 4630 * Return connecting socket to remote host:port or local socket path, 4631 * passing back the failure reason if appropriate. 4632 */ 4633 static int 4634 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4635 char *ctype, char *rname, struct channel_connect *cctx, 4636 int *reason, const char **errmsg) 4637 { 4638 struct addrinfo hints; 4639 int gaierr; 4640 int sock = -1; 4641 char strport[NI_MAXSERV]; 4642 4643 if (port == PORT_STREAMLOCAL) { 4644 struct sockaddr_un *sunaddr; 4645 struct addrinfo *ai; 4646 4647 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4648 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4649 return -1; 4650 } 4651 4652 /* 4653 * Fake up a struct addrinfo for AF_UNIX connections. 4654 * channel_connect_ctx_free() must check ai_family 4655 * and use free() not freeaddirinfo() for AF_UNIX. 4656 */ 4657 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4658 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4659 ai->ai_addr = (struct sockaddr *)(ai + 1); 4660 ai->ai_addrlen = sizeof(*sunaddr); 4661 ai->ai_family = AF_UNIX; 4662 ai->ai_socktype = socktype; 4663 ai->ai_protocol = PF_UNSPEC; 4664 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4665 sunaddr->sun_family = AF_UNIX; 4666 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4667 cctx->aitop = ai; 4668 } else { 4669 memset(&hints, 0, sizeof(hints)); 4670 hints.ai_family = ssh->chanctxt->IPv4or6; 4671 hints.ai_socktype = socktype; 4672 snprintf(strport, sizeof strport, "%d", port); 4673 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4674 != 0) { 4675 if (errmsg != NULL) 4676 *errmsg = ssh_gai_strerror(gaierr); 4677 if (reason != NULL) 4678 *reason = SSH2_OPEN_CONNECT_FAILED; 4679 error("connect_to %.100s: unknown host (%s)", name, 4680 ssh_gai_strerror(gaierr)); 4681 return -1; 4682 } 4683 } 4684 4685 cctx->host = xstrdup(name); 4686 cctx->port = port; 4687 cctx->ai = cctx->aitop; 4688 4689 if ((sock = connect_next(cctx)) == -1) { 4690 error("connect to %.100s port %d failed: %s", 4691 name, port, strerror(errno)); 4692 return -1; 4693 } 4694 4695 return sock; 4696 } 4697 4698 /* Return CONNECTING channel to remote host:port or local socket path */ 4699 static Channel * 4700 connect_to(struct ssh *ssh, const char *host, int port, 4701 char *ctype, char *rname) 4702 { 4703 struct channel_connect cctx; 4704 Channel *c; 4705 int sock; 4706 4707 memset(&cctx, 0, sizeof(cctx)); 4708 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4709 &cctx, NULL, NULL); 4710 if (sock == -1) { 4711 channel_connect_ctx_free(&cctx); 4712 return NULL; 4713 } 4714 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4715 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4716 c->host_port = port; 4717 c->path = xstrdup(host); 4718 c->connect_ctx = cctx; 4719 4720 return c; 4721 } 4722 4723 /* 4724 * returns either the newly connected channel or the downstream channel 4725 * that needs to deal with this connection. 4726 */ 4727 Channel * 4728 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4729 u_short listen_port, char *ctype, char *rname) 4730 { 4731 struct ssh_channels *sc = ssh->chanctxt; 4732 struct permission_set *pset = &sc->local_perms; 4733 u_int i; 4734 struct permission *perm; 4735 4736 for (i = 0; i < pset->num_permitted_user; i++) { 4737 perm = &pset->permitted_user[i]; 4738 if (open_listen_match_tcpip(perm, 4739 listen_host, listen_port, 1)) { 4740 if (perm->downstream) 4741 return perm->downstream; 4742 if (perm->port_to_connect == 0) 4743 return rdynamic_connect_prepare(ssh, 4744 ctype, rname); 4745 return connect_to(ssh, 4746 perm->host_to_connect, perm->port_to_connect, 4747 ctype, rname); 4748 } 4749 } 4750 error("WARNING: Server requests forwarding for unknown listen_port %d", 4751 listen_port); 4752 return NULL; 4753 } 4754 4755 Channel * 4756 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4757 char *ctype, char *rname) 4758 { 4759 struct ssh_channels *sc = ssh->chanctxt; 4760 struct permission_set *pset = &sc->local_perms; 4761 u_int i; 4762 struct permission *perm; 4763 4764 for (i = 0; i < pset->num_permitted_user; i++) { 4765 perm = &pset->permitted_user[i]; 4766 if (open_listen_match_streamlocal(perm, path)) { 4767 return connect_to(ssh, 4768 perm->host_to_connect, perm->port_to_connect, 4769 ctype, rname); 4770 } 4771 } 4772 error("WARNING: Server requests forwarding for unknown path %.100s", 4773 path); 4774 return NULL; 4775 } 4776 4777 /* Check if connecting to that port is permitted and connect. */ 4778 Channel * 4779 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4780 char *ctype, char *rname, int *reason, const char **errmsg) 4781 { 4782 struct ssh_channels *sc = ssh->chanctxt; 4783 struct permission_set *pset = &sc->local_perms; 4784 struct channel_connect cctx; 4785 Channel *c; 4786 u_int i, permit, permit_adm = 1; 4787 int sock; 4788 struct permission *perm; 4789 4790 permit = pset->all_permitted; 4791 if (!permit) { 4792 for (i = 0; i < pset->num_permitted_user; i++) { 4793 perm = &pset->permitted_user[i]; 4794 if (open_match(perm, host, port)) { 4795 permit = 1; 4796 break; 4797 } 4798 } 4799 } 4800 4801 if (pset->num_permitted_admin > 0) { 4802 permit_adm = 0; 4803 for (i = 0; i < pset->num_permitted_admin; i++) { 4804 perm = &pset->permitted_admin[i]; 4805 if (open_match(perm, host, port)) { 4806 permit_adm = 1; 4807 break; 4808 } 4809 } 4810 } 4811 4812 if (!permit || !permit_adm) { 4813 logit("Received request from %.100s port %d to connect to " 4814 "host %.100s port %d, but the request was denied.", 4815 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4816 if (reason != NULL) 4817 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4818 return NULL; 4819 } 4820 4821 memset(&cctx, 0, sizeof(cctx)); 4822 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4823 &cctx, reason, errmsg); 4824 if (sock == -1) { 4825 channel_connect_ctx_free(&cctx); 4826 return NULL; 4827 } 4828 4829 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4830 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4831 c->host_port = port; 4832 c->path = xstrdup(host); 4833 c->connect_ctx = cctx; 4834 4835 return c; 4836 } 4837 4838 /* Check if connecting to that path is permitted and connect. */ 4839 Channel * 4840 channel_connect_to_path(struct ssh *ssh, const char *path, 4841 char *ctype, char *rname) 4842 { 4843 struct ssh_channels *sc = ssh->chanctxt; 4844 struct permission_set *pset = &sc->local_perms; 4845 u_int i, permit, permit_adm = 1; 4846 struct permission *perm; 4847 4848 permit = pset->all_permitted; 4849 if (!permit) { 4850 for (i = 0; i < pset->num_permitted_user; i++) { 4851 perm = &pset->permitted_user[i]; 4852 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4853 permit = 1; 4854 break; 4855 } 4856 } 4857 } 4858 4859 if (pset->num_permitted_admin > 0) { 4860 permit_adm = 0; 4861 for (i = 0; i < pset->num_permitted_admin; i++) { 4862 perm = &pset->permitted_admin[i]; 4863 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4864 permit_adm = 1; 4865 break; 4866 } 4867 } 4868 } 4869 4870 if (!permit || !permit_adm) { 4871 logit("Received request to connect to path %.100s, " 4872 "but the request was denied.", path); 4873 return NULL; 4874 } 4875 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4876 } 4877 4878 void 4879 channel_send_window_changes(struct ssh *ssh) 4880 { 4881 struct ssh_channels *sc = ssh->chanctxt; 4882 struct winsize ws; 4883 int r; 4884 u_int i; 4885 4886 for (i = 0; i < sc->channels_alloc; i++) { 4887 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4888 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4889 continue; 4890 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4891 continue; 4892 channel_request_start(ssh, i, "window-change", 0); 4893 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4894 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4895 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4896 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4897 (r = sshpkt_send(ssh)) != 0) 4898 fatal_fr(r, "channel %u; send window-change", i); 4899 } 4900 } 4901 4902 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4903 static Channel * 4904 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4905 { 4906 Channel *c; 4907 int r; 4908 4909 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4910 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4911 c->host_port = 0; 4912 c->path = NULL; 4913 4914 /* 4915 * We need to open the channel before we have a FD, 4916 * so that we can get SOCKS header from peer. 4917 */ 4918 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4919 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4920 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4921 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4922 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4923 fatal_fr(r, "channel %i; confirm", c->self); 4924 return c; 4925 } 4926 4927 /* Return CONNECTING socket to remote host:port or local socket path */ 4928 static int 4929 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4930 { 4931 struct ssh_channels *sc = ssh->chanctxt; 4932 struct permission_set *pset = &sc->local_perms; 4933 struct permission *perm; 4934 struct channel_connect cctx; 4935 u_int i, permit_adm = 1; 4936 int sock; 4937 4938 if (pset->num_permitted_admin > 0) { 4939 permit_adm = 0; 4940 for (i = 0; i < pset->num_permitted_admin; i++) { 4941 perm = &pset->permitted_admin[i]; 4942 if (open_match(perm, c->path, c->host_port)) { 4943 permit_adm = 1; 4944 break; 4945 } 4946 } 4947 } 4948 if (!permit_adm) { 4949 debug_f("requested forward not permitted"); 4950 return -1; 4951 } 4952 4953 memset(&cctx, 0, sizeof(cctx)); 4954 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4955 NULL, &cctx, NULL, NULL); 4956 if (sock == -1) 4957 channel_connect_ctx_free(&cctx); 4958 else { 4959 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4960 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4961 c->connect_ctx = cctx; 4962 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4963 } 4964 return sock; 4965 } 4966 4967 /* -- X11 forwarding */ 4968 4969 /* 4970 * Creates an internet domain socket for listening for X11 connections. 4971 * Returns 0 and a suitable display number for the DISPLAY variable 4972 * stored in display_numberp , or -1 if an error occurs. 4973 */ 4974 int 4975 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4976 int x11_use_localhost, int single_connection, 4977 u_int *display_numberp, int **chanids) 4978 { 4979 Channel *nc = NULL; 4980 int display_number, sock; 4981 u_short port; 4982 struct addrinfo hints, *ai, *aitop; 4983 char strport[NI_MAXSERV]; 4984 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4985 4986 if (chanids == NULL) 4987 return -1; 4988 4989 for (display_number = x11_display_offset; 4990 display_number < MAX_DISPLAYS; 4991 display_number++) { 4992 port = 6000 + display_number; 4993 memset(&hints, 0, sizeof(hints)); 4994 hints.ai_family = ssh->chanctxt->IPv4or6; 4995 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4996 hints.ai_socktype = SOCK_STREAM; 4997 snprintf(strport, sizeof strport, "%d", port); 4998 if ((gaierr = getaddrinfo(NULL, strport, 4999 &hints, &aitop)) != 0) { 5000 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 5001 return -1; 5002 } 5003 for (ai = aitop; ai; ai = ai->ai_next) { 5004 if (ai->ai_family != AF_INET && 5005 ai->ai_family != AF_INET6) 5006 continue; 5007 sock = socket(ai->ai_family, ai->ai_socktype, 5008 ai->ai_protocol); 5009 if (sock == -1) { 5010 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 5011 #ifdef EPFNOSUPPORT 5012 && (errno != EPFNOSUPPORT) 5013 #endif 5014 ) { 5015 error("socket: %.100s", strerror(errno)); 5016 freeaddrinfo(aitop); 5017 return -1; 5018 } else { 5019 debug("x11_create_display_inet: Socket family %d not supported", 5020 ai->ai_family); 5021 continue; 5022 } 5023 } 5024 if (ai->ai_family == AF_INET6) 5025 sock_set_v6only(sock); 5026 if (x11_use_localhost) 5027 set_reuseaddr(sock); 5028 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5029 debug2_f("bind port %d: %.100s", port, 5030 strerror(errno)); 5031 close(sock); 5032 for (n = 0; n < num_socks; n++) 5033 close(socks[n]); 5034 num_socks = 0; 5035 break; 5036 } 5037 socks[num_socks++] = sock; 5038 if (num_socks == NUM_SOCKS) 5039 break; 5040 } 5041 freeaddrinfo(aitop); 5042 if (num_socks > 0) 5043 break; 5044 } 5045 if (display_number >= MAX_DISPLAYS) { 5046 error("Failed to allocate internet-domain X11 display socket."); 5047 return -1; 5048 } 5049 /* Start listening for connections on the socket. */ 5050 for (n = 0; n < num_socks; n++) { 5051 sock = socks[n]; 5052 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5053 error("listen: %.100s", strerror(errno)); 5054 close(sock); 5055 return -1; 5056 } 5057 } 5058 5059 /* Allocate a channel for each socket. */ 5060 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5061 for (n = 0; n < num_socks; n++) { 5062 sock = socks[n]; 5063 nc = channel_new(ssh, "x11-listener", 5064 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5065 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5066 0, "X11 inet listener", 1); 5067 nc->single_connection = single_connection; 5068 (*chanids)[n] = nc->self; 5069 } 5070 (*chanids)[n] = -1; 5071 5072 /* Return the display number for the DISPLAY environment variable. */ 5073 *display_numberp = display_number; 5074 return 0; 5075 } 5076 5077 static int 5078 connect_local_xsocket_path(const char *pathname) 5079 { 5080 int sock; 5081 struct sockaddr_un addr; 5082 5083 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5084 if (sock == -1) { 5085 error("socket: %.100s", strerror(errno)); 5086 return -1; 5087 } 5088 memset(&addr, 0, sizeof(addr)); 5089 addr.sun_family = AF_UNIX; 5090 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 5091 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5092 return sock; 5093 close(sock); 5094 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5095 return -1; 5096 } 5097 5098 static int 5099 connect_local_xsocket(u_int dnr) 5100 { 5101 char buf[1024]; 5102 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 5103 return connect_local_xsocket_path(buf); 5104 } 5105 5106 #ifdef __APPLE__ 5107 static int 5108 is_path_to_xsocket(const char *display, char *path, size_t pathlen) 5109 { 5110 struct stat sbuf; 5111 5112 if (strlcpy(path, display, pathlen) >= pathlen) { 5113 error("%s: display path too long", __func__); 5114 return 0; 5115 } 5116 if (display[0] != '/') 5117 return 0; 5118 if (stat(path, &sbuf) == 0) { 5119 return 1; 5120 } else { 5121 char *dot = strrchr(path, '.'); 5122 if (dot != NULL) { 5123 *dot = '\0'; 5124 if (stat(path, &sbuf) == 0) { 5125 return 1; 5126 } 5127 } 5128 } 5129 return 0; 5130 } 5131 #endif 5132 5133 int 5134 x11_connect_display(struct ssh *ssh) 5135 { 5136 u_int display_number; 5137 const char *display; 5138 char buf[1024], *cp; 5139 struct addrinfo hints, *ai, *aitop; 5140 char strport[NI_MAXSERV]; 5141 int gaierr, sock = 0; 5142 5143 /* Try to open a socket for the local X server. */ 5144 display = getenv("DISPLAY"); 5145 if (!display) { 5146 error("DISPLAY not set."); 5147 return -1; 5148 } 5149 /* 5150 * Now we decode the value of the DISPLAY variable and make a 5151 * connection to the real X server. 5152 */ 5153 5154 #ifdef __APPLE__ 5155 /* Check if display is a path to a socket (as set by launchd). */ 5156 { 5157 char path[PATH_MAX]; 5158 5159 if (is_path_to_xsocket(display, path, sizeof(path))) { 5160 debug("x11_connect_display: $DISPLAY is launchd"); 5161 5162 /* Create a socket. */ 5163 sock = connect_local_xsocket_path(path); 5164 if (sock < 0) 5165 return -1; 5166 5167 /* OK, we now have a connection to the display. */ 5168 return sock; 5169 } 5170 } 5171 #endif 5172 /* 5173 * Check if it is a unix domain socket. Unix domain displays are in 5174 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5175 */ 5176 if (strncmp(display, "unix:", 5) == 0 || 5177 display[0] == ':') { 5178 /* Connect to the unix domain socket. */ 5179 if (sscanf(strrchr(display, ':') + 1, "%u", 5180 &display_number) != 1) { 5181 error("Could not parse display number from DISPLAY: " 5182 "%.100s", display); 5183 return -1; 5184 } 5185 /* Create a socket. */ 5186 sock = connect_local_xsocket(display_number); 5187 if (sock < 0) 5188 return -1; 5189 5190 /* OK, we now have a connection to the display. */ 5191 return sock; 5192 } 5193 /* 5194 * Connect to an inet socket. The DISPLAY value is supposedly 5195 * hostname:d[.s], where hostname may also be numeric IP address. 5196 */ 5197 strlcpy(buf, display, sizeof(buf)); 5198 cp = strchr(buf, ':'); 5199 if (!cp) { 5200 error("Could not find ':' in DISPLAY: %.100s", display); 5201 return -1; 5202 } 5203 *cp = 0; 5204 /* 5205 * buf now contains the host name. But first we parse the 5206 * display number. 5207 */ 5208 if (sscanf(cp + 1, "%u", &display_number) != 1) { 5209 error("Could not parse display number from DISPLAY: %.100s", 5210 display); 5211 return -1; 5212 } 5213 5214 /* Look up the host address */ 5215 memset(&hints, 0, sizeof(hints)); 5216 hints.ai_family = ssh->chanctxt->IPv4or6; 5217 hints.ai_socktype = SOCK_STREAM; 5218 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 5219 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5220 error("%.100s: unknown host. (%s)", buf, 5221 ssh_gai_strerror(gaierr)); 5222 return -1; 5223 } 5224 for (ai = aitop; ai; ai = ai->ai_next) { 5225 /* Create a socket. */ 5226 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5227 if (sock == -1) { 5228 debug2("socket: %.100s", strerror(errno)); 5229 continue; 5230 } 5231 /* Connect it to the display. */ 5232 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5233 debug2("connect %.100s port %u: %.100s", buf, 5234 6000 + display_number, strerror(errno)); 5235 close(sock); 5236 continue; 5237 } 5238 /* Success */ 5239 break; 5240 } 5241 freeaddrinfo(aitop); 5242 if (!ai) { 5243 error("connect %.100s port %u: %.100s", buf, 5244 6000 + display_number, strerror(errno)); 5245 return -1; 5246 } 5247 set_nodelay(sock); 5248 return sock; 5249 } 5250 5251 /* 5252 * Requests forwarding of X11 connections, generates fake authentication 5253 * data, and enables authentication spoofing. 5254 * This should be called in the client only. 5255 */ 5256 void 5257 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5258 const char *disp, const char *proto, const char *data, int want_reply) 5259 { 5260 struct ssh_channels *sc = ssh->chanctxt; 5261 u_int data_len = (u_int) strlen(data) / 2; 5262 u_int i, value; 5263 const char *cp; 5264 char *new_data; 5265 int r, screen_number; 5266 5267 if (sc->x11_saved_display == NULL) 5268 sc->x11_saved_display = xstrdup(disp); 5269 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5270 error("x11_request_forwarding_with_spoofing: different " 5271 "$DISPLAY already forwarded"); 5272 return; 5273 } 5274 5275 cp = strchr(disp, ':'); 5276 if (cp) 5277 cp = strchr(cp, '.'); 5278 if (cp) 5279 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5280 else 5281 screen_number = 0; 5282 5283 if (sc->x11_saved_proto == NULL) { 5284 /* Save protocol name. */ 5285 sc->x11_saved_proto = xstrdup(proto); 5286 5287 /* Extract real authentication data. */ 5288 sc->x11_saved_data = xmalloc(data_len); 5289 for (i = 0; i < data_len; i++) { 5290 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5291 fatal("x11_request_forwarding: bad " 5292 "authentication data: %.100s", data); 5293 } 5294 sc->x11_saved_data[i] = value; 5295 } 5296 sc->x11_saved_data_len = data_len; 5297 5298 /* Generate fake data of the same length. */ 5299 sc->x11_fake_data = xmalloc(data_len); 5300 arc4random_buf(sc->x11_fake_data, data_len); 5301 sc->x11_fake_data_len = data_len; 5302 } 5303 5304 /* Convert the fake data into hex. */ 5305 new_data = tohex(sc->x11_fake_data, data_len); 5306 5307 /* Send the request packet. */ 5308 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5309 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5310 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5311 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5312 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5313 (r = sshpkt_send(ssh)) != 0 || 5314 (r = ssh_packet_write_wait(ssh)) != 0) 5315 fatal_fr(r, "send x11-req"); 5316 free(new_data); 5317 } 5318