1 /* $OpenBSD: channels.c,v 1.463 2026/06/24 11:59:09 dtucker Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include "includes.h" 43 44 #include <sys/types.h> 45 #include <sys/stat.h> 46 #include <sys/ioctl.h> 47 #include <sys/un.h> 48 #include <sys/socket.h> 49 #include <sys/queue.h> 50 51 #include <netinet/in.h> 52 #include <arpa/inet.h> 53 54 #include <errno.h> 55 #include <fcntl.h> 56 #include <limits.h> 57 #include <netdb.h> 58 #include <poll.h> 59 #include <stdarg.h> 60 #include <stdint.h> 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <string.h> 64 #include <termios.h> 65 #include <unistd.h> 66 67 #include "xmalloc.h" 68 #include "ssh.h" 69 #include "ssh2.h" 70 #include "ssherr.h" 71 #include "sshbuf.h" 72 #include "packet.h" 73 #include "log.h" 74 #include "misc.h" 75 #include "channels.h" 76 #include "compat.h" 77 #include "canohost.h" 78 #include "pathnames.h" 79 #include "match.h" 80 81 /* XXX remove once we're satisfied there's no lurking bugs */ 82 /* #define DEBUG_CHANNEL_POLL 1 */ 83 84 /* -- agent forwarding */ 85 #define NUM_SOCKS 10 86 87 /* -- X11 forwarding */ 88 /* X11 port for display :0 */ 89 #define X11_BASE_PORT 6000 90 /* Maximum number of fake X11 displays to try. */ 91 #define MAX_DISPLAYS 1000 92 93 /* Per-channel callback for pre/post IO actions */ 94 typedef void chan_fn(struct ssh *, Channel *c); 95 96 /* 97 * Data structure for storing which hosts are permitted for forward requests. 98 * The local sides of any remote forwards are stored in this array to prevent 99 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 100 * network (which might be behind a firewall). 101 */ 102 /* XXX: streamlocal wants a path instead of host:port */ 103 /* Overload host_to_connect; we could just make this match Forward */ 104 /* XXX - can we use listen_host instead of listen_path? */ 105 struct permission { 106 char *host_to_connect; /* Connect to 'host'. */ 107 int port_to_connect; /* Connect to 'port'. */ 108 char *listen_host; /* Remote side should listen address. */ 109 char *listen_path; /* Remote side should listen path. */ 110 int listen_port; /* Remote side should listen port. */ 111 Channel *downstream; /* Downstream mux*/ 112 }; 113 114 /* 115 * Stores the forwarding permission state for a single direction (local or 116 * remote). 117 */ 118 struct permission_set { 119 /* 120 * List of all local permitted host/port pairs to allow for the 121 * user. 122 */ 123 u_int num_permitted_user; 124 struct permission *permitted_user; 125 126 /* 127 * List of all permitted host/port pairs to allow for the admin. 128 */ 129 u_int num_permitted_admin; 130 struct permission *permitted_admin; 131 132 /* 133 * If this is true, all opens/listens are permitted. This is the 134 * case on the server on which we have to trust the client anyway, 135 * and the user could do anything after logging in. 136 */ 137 int all_permitted; 138 }; 139 140 /* Used to record timeouts per channel type */ 141 struct ssh_channel_timeout { 142 char *type_pattern; 143 int timeout_secs; 144 }; 145 146 /* Master structure for channels state */ 147 struct ssh_channels { 148 /* 149 * Pointer to an array containing all allocated channels. The array 150 * is dynamically extended as needed. 151 */ 152 Channel **channels; 153 154 /* 155 * Size of the channel array. All slots of the array must always be 156 * initialized (at least the type field); unused slots set to NULL 157 */ 158 u_int channels_alloc; 159 160 /* 161 * 'channel_pre*' are called just before IO to add any bits 162 * relevant to channels in the c->io_want bitmasks. 163 * 164 * 'channel_post*': perform any appropriate operations for 165 * channels which have c->io_ready events pending. 166 */ 167 chan_fn **channel_pre; 168 chan_fn **channel_post; 169 170 /* -- tcp forwarding */ 171 struct permission_set local_perms; 172 struct permission_set remote_perms; 173 174 /* -- X11 forwarding */ 175 176 /* Saved X11 local (client) display. */ 177 char *x11_saved_display; 178 179 /* Saved X11 authentication protocol name. */ 180 char *x11_saved_proto; 181 182 /* Saved X11 authentication data. This is the real data. */ 183 char *x11_saved_data; 184 u_int x11_saved_data_len; 185 186 /* Deadline after which all X11 connections are refused */ 187 time_t x11_refuse_time; 188 189 /* 190 * Fake X11 authentication data. This is what the server will be 191 * sending us; we should replace any occurrences of this by the 192 * real data. 193 */ 194 u_char *x11_fake_data; 195 u_int x11_fake_data_len; 196 197 /* AF_UNSPEC or AF_INET or AF_INET6 */ 198 int IPv4or6; 199 200 /* Channel timeouts by type */ 201 struct ssh_channel_timeout *timeouts; 202 size_t ntimeouts; 203 /* Global timeout for all OPEN channels */ 204 int global_deadline; 205 time_t lastused; 206 /* pattern-lists used to classify channels as bulk */ 207 char *bulk_classifier_tty, *bulk_classifier_notty; 208 /* Number of active bulk channels (set by channel_handler) */ 209 u_int nbulk; 210 }; 211 212 /* helper */ 213 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 214 static const char *channel_rfwd_bind_host(const char *listen_host); 215 216 /* non-blocking connect helpers */ 217 static int connect_next(struct channel_connect *); 218 static void channel_connect_ctx_free(struct channel_connect *); 219 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 220 static int rdynamic_connect_finish(struct ssh *, Channel *); 221 222 /* Setup helper */ 223 static void channel_handler_init(struct ssh_channels *sc); 224 225 /* -- channel core */ 226 227 void 228 channel_init_channels(struct ssh *ssh) 229 { 230 struct ssh_channels *sc; 231 232 if ((sc = calloc(1, sizeof(*sc))) == NULL) 233 fatal_f("allocation failed"); 234 sc->channels_alloc = 10; 235 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 236 sc->IPv4or6 = AF_UNSPEC; 237 sc->bulk_classifier_tty = xstrdup(CHANNEL_BULK_TTY); 238 sc->bulk_classifier_notty = xstrdup(CHANNEL_BULK_NOTTY); 239 channel_handler_init(sc); 240 241 ssh->chanctxt = sc; 242 } 243 244 Channel * 245 channel_by_id(struct ssh *ssh, int id) 246 { 247 Channel *c; 248 249 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 250 logit_f("%d: bad id", id); 251 return NULL; 252 } 253 c = ssh->chanctxt->channels[id]; 254 if (c == NULL) { 255 logit_f("%d: bad id: channel free", id); 256 return NULL; 257 } 258 return c; 259 } 260 261 Channel * 262 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 263 { 264 Channel *c; 265 u_int i; 266 267 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 268 c = ssh->chanctxt->channels[i]; 269 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 270 return c; 271 } 272 return NULL; 273 } 274 275 /* 276 * Returns the channel if it is allowed to receive protocol messages. 277 * Private channels, like listening sockets, may not receive messages. 278 */ 279 Channel * 280 channel_lookup(struct ssh *ssh, int id) 281 { 282 Channel *c; 283 284 if ((c = channel_by_id(ssh, id)) == NULL) 285 return NULL; 286 287 switch (c->type) { 288 case SSH_CHANNEL_X11_OPEN: 289 case SSH_CHANNEL_LARVAL: 290 case SSH_CHANNEL_CONNECTING: 291 case SSH_CHANNEL_DYNAMIC: 292 case SSH_CHANNEL_RDYNAMIC_OPEN: 293 case SSH_CHANNEL_RDYNAMIC_FINISH: 294 case SSH_CHANNEL_OPENING: 295 case SSH_CHANNEL_OPEN: 296 case SSH_CHANNEL_ABANDONED: 297 case SSH_CHANNEL_MUX_PROXY: 298 return c; 299 } 300 logit("Non-public channel %d, type %d.", id, c->type); 301 return NULL; 302 } 303 304 /* 305 * Add a timeout for open channels whose c->ctype (or c->xctype if it is set) 306 * match type_pattern. 307 */ 308 void 309 channel_add_timeout(struct ssh *ssh, const char *type_pattern, 310 int timeout_secs) 311 { 312 struct ssh_channels *sc = ssh->chanctxt; 313 314 if (strcmp(type_pattern, "global") == 0) { 315 debug2_f("global channel timeout %d seconds", timeout_secs); 316 sc->global_deadline = timeout_secs; 317 return; 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 static void 358 channel_classify(struct ssh *ssh, Channel *c) 359 { 360 struct ssh_channels *sc = ssh->chanctxt; 361 const char *type = c->xctype == NULL ? c->ctype : c->xctype; 362 const int has_tty = c->isatty || c->remote_has_tty; 363 const char *classifier = has_tty ? 364 sc->bulk_classifier_tty : sc->bulk_classifier_notty; 365 366 c->bulk = type != NULL && match_pattern_list(type, classifier, 0) == 1; 367 debug3("channel %d: classify type \"%s\" (%s) as %s", c->self, 368 type ? type : "(null)", has_tty ? "with TTY" : "no TTY", 369 c->bulk ? "bulk" : "interactive"); 370 } 371 372 /* 373 * Sets "extended type" of a channel; used by session layer to add additional 374 * information about channel types (e.g. shell, login, subsystem) that can then 375 * be used to select timeouts and DSCP values. 376 * Will reset c->inactive_deadline as a side-effect. 377 */ 378 void 379 channel_set_xtype(struct ssh *ssh, int id, const char *xctype) 380 { 381 Channel *c; 382 383 if ((c = channel_by_id(ssh, id)) == NULL) 384 fatal_f("missing channel %d", id); 385 if (c->xctype != NULL) 386 free(c->xctype); 387 c->xctype = xstrdup(xctype); 388 /* Type has changed, so look up inactivity deadline again */ 389 c->inactive_deadline = lookup_timeout(ssh, c->xctype); 390 channel_classify(ssh, c); 391 debug2_f("labeled channel %d as %s (inactive timeout %u)", id, xctype, 392 c->inactive_deadline); 393 } 394 395 /* 396 * update "last used" time on a channel. 397 * NB. nothing else should update lastused except to clear it. 398 */ 399 static void 400 channel_set_used_time(struct ssh *ssh, Channel *c) 401 { 402 ssh->chanctxt->lastused = monotime(); 403 if (c != NULL) 404 c->lastused = ssh->chanctxt->lastused; 405 } 406 407 /* 408 * Get the time at which a channel is due to time out for inactivity. 409 * Returns 0 if the channel is not due to time out ever. 410 */ 411 static time_t 412 channel_get_expiry(struct ssh *ssh, Channel *c) 413 { 414 struct ssh_channels *sc = ssh->chanctxt; 415 time_t expiry = 0, channel_expiry; 416 417 if (sc->lastused != 0 && sc->global_deadline != 0) 418 expiry = sc->lastused + sc->global_deadline; 419 if (c->lastused != 0 && c->inactive_deadline != 0) { 420 channel_expiry = c->lastused + c->inactive_deadline; 421 if (expiry == 0 || channel_expiry < expiry) 422 expiry = channel_expiry; 423 } 424 return expiry; 425 } 426 427 /* Returns non-zero if there is an open, non-interactive channel */ 428 int 429 channel_has_bulk(struct ssh *ssh) 430 { 431 return ssh->chanctxt != NULL && ssh->chanctxt->nbulk != 0; 432 } 433 434 /* 435 * Register filedescriptors for a channel, used when allocating a channel or 436 * when the channel consumer/producer is ready, e.g. shell exec'd 437 */ 438 static void 439 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 440 int extusage, int nonblock, int is_tty) 441 { 442 int val; 443 444 if (rfd != -1) 445 (void)fcntl(rfd, F_SETFD, FD_CLOEXEC); 446 if (wfd != -1 && wfd != rfd) 447 (void)fcntl(wfd, F_SETFD, FD_CLOEXEC); 448 if (efd != -1 && efd != rfd && efd != wfd) 449 (void)fcntl(efd, F_SETFD, FD_CLOEXEC); 450 451 c->rfd = rfd; 452 c->wfd = wfd; 453 c->sock = (rfd == wfd) ? rfd : -1; 454 c->efd = efd; 455 c->extended_usage = extusage; 456 457 if ((c->isatty = is_tty) != 0) 458 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 459 #ifdef _AIX 460 /* XXX: Later AIX versions can't push as much data to tty */ 461 c->wfd_isatty = is_tty || isatty(c->wfd); 462 #endif 463 464 /* enable nonblocking mode */ 465 c->restore_block = 0; 466 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 467 /* 468 * Special handling for stdio file descriptors: do not set 469 * non-blocking mode if they are TTYs. Otherwise prepare to 470 * restore their blocking state on exit to avoid interfering 471 * with other programs that follow. 472 */ 473 if (rfd != -1 && !isatty(rfd) && 474 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 475 c->restore_flags[0] = val; 476 c->restore_block |= CHANNEL_RESTORE_RFD; 477 set_nonblock(rfd); 478 } 479 if (wfd != -1 && !isatty(wfd) && 480 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 481 c->restore_flags[1] = val; 482 c->restore_block |= CHANNEL_RESTORE_WFD; 483 set_nonblock(wfd); 484 } 485 if (efd != -1 && !isatty(efd) && 486 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 487 c->restore_flags[2] = val; 488 c->restore_block |= CHANNEL_RESTORE_EFD; 489 set_nonblock(efd); 490 } 491 } else if (nonblock) { 492 if (rfd != -1) 493 set_nonblock(rfd); 494 if (wfd != -1) 495 set_nonblock(wfd); 496 if (efd != -1) 497 set_nonblock(efd); 498 } 499 /* channel might be entering a larval state, so reset global timeout */ 500 channel_set_used_time(ssh, NULL); 501 channel_classify(ssh, c); 502 } 503 504 /* 505 * Allocate a new channel object and set its type and socket. 506 */ 507 Channel * 508 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 509 u_int window, u_int maxpack, int extusage, const char *remote_name, 510 int nonblock) 511 { 512 struct ssh_channels *sc = ssh->chanctxt; 513 u_int i, found = 0; 514 Channel *c; 515 int r; 516 517 /* Try to find a free slot where to put the new channel. */ 518 for (i = 0; i < sc->channels_alloc; i++) { 519 if (sc->channels[i] == NULL) { 520 /* Found a free slot. */ 521 found = i; 522 break; 523 } 524 } 525 if (i >= sc->channels_alloc) { 526 /* 527 * There are no free slots. Take last+1 slot and expand 528 * the array. 529 */ 530 found = sc->channels_alloc; 531 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 532 fatal_f("internal error: channels_alloc %d too big", 533 sc->channels_alloc); 534 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 535 sc->channels_alloc + 10, sizeof(*sc->channels)); 536 sc->channels_alloc += 10; 537 debug2("channel: expanding %d", sc->channels_alloc); 538 } 539 /* Initialize and return new channel. */ 540 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 541 if ((c->input = sshbuf_new()) == NULL || 542 (c->output = sshbuf_new()) == NULL || 543 (c->extended = sshbuf_new()) == NULL) 544 fatal_f("sshbuf_new failed"); 545 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 546 fatal_fr(r, "sshbuf_set_max_size"); 547 c->ostate = CHAN_OUTPUT_OPEN; 548 c->istate = CHAN_INPUT_OPEN; 549 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 550 c->self = found; 551 c->type = type; 552 c->ctype = ctype; 553 c->local_window = window; 554 c->local_window_max = window; 555 c->local_maxpacket = maxpack; 556 c->remote_name = xstrdup(remote_name); 557 c->ctl_chan = -1; 558 c->delayed = 1; /* prevent call to channel_post handler */ 559 c->inactive_deadline = lookup_timeout(ssh, c->ctype); 560 TAILQ_INIT(&c->status_confirms); 561 channel_classify(ssh, c); 562 debug("channel %d: new %s [%s] (inactive timeout: %u)", 563 found, c->ctype, remote_name, c->inactive_deadline); 564 return c; 565 } 566 567 void 568 channel_set_tty(struct ssh *ssh, Channel *c) 569 { 570 c->remote_has_tty = 1; 571 channel_classify(ssh, c); 572 } 573 574 int 575 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 576 { 577 int ret, fd = *fdp; 578 579 if (fd == -1) 580 return 0; 581 582 /* restore blocking */ 583 if (*fdp == c->rfd && 584 (c->restore_block & CHANNEL_RESTORE_RFD) != 0) 585 (void)fcntl(*fdp, F_SETFL, c->restore_flags[0]); 586 else if (*fdp == c->wfd && 587 (c->restore_block & CHANNEL_RESTORE_WFD) != 0) 588 (void)fcntl(*fdp, F_SETFL, c->restore_flags[1]); 589 else if (*fdp == c->efd && 590 (c->restore_block & CHANNEL_RESTORE_EFD) != 0) 591 (void)fcntl(*fdp, F_SETFL, c->restore_flags[2]); 592 593 if (*fdp == c->rfd) { 594 c->io_want &= ~SSH_CHAN_IO_RFD; 595 c->io_ready &= ~SSH_CHAN_IO_RFD; 596 c->rfd = -1; 597 c->pfds[0] = -1; 598 } 599 if (*fdp == c->wfd) { 600 c->io_want &= ~SSH_CHAN_IO_WFD; 601 c->io_ready &= ~SSH_CHAN_IO_WFD; 602 c->wfd = -1; 603 c->pfds[1] = -1; 604 } 605 if (*fdp == c->efd) { 606 c->io_want &= ~SSH_CHAN_IO_EFD; 607 c->io_ready &= ~SSH_CHAN_IO_EFD; 608 c->efd = -1; 609 c->pfds[2] = -1; 610 } 611 if (*fdp == c->sock) { 612 c->io_want &= ~SSH_CHAN_IO_SOCK; 613 c->io_ready &= ~SSH_CHAN_IO_SOCK; 614 c->sock = -1; 615 c->pfds[3] = -1; 616 } 617 618 ret = close(fd); 619 *fdp = -1; /* probably redundant */ 620 return ret; 621 } 622 623 /* Close all channel fd/socket. */ 624 static void 625 channel_close_fds(struct ssh *ssh, Channel *c) 626 { 627 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 628 629 channel_close_fd(ssh, c, &c->sock); 630 if (rfd != sock) 631 channel_close_fd(ssh, c, &c->rfd); 632 if (wfd != sock && wfd != rfd) 633 channel_close_fd(ssh, c, &c->wfd); 634 if (efd != sock && efd != rfd && efd != wfd) 635 channel_close_fd(ssh, c, &c->efd); 636 } 637 638 static void 639 fwd_perm_clear(struct permission *perm) 640 { 641 free(perm->host_to_connect); 642 free(perm->listen_host); 643 free(perm->listen_path); 644 memset(perm, 0, sizeof(*perm)); 645 } 646 647 /* Returns an printable name for the specified forwarding permission list */ 648 static const char * 649 fwd_ident(int who, int where) 650 { 651 if (who == FORWARD_ADM) { 652 if (where == FORWARD_LOCAL) 653 return "admin local"; 654 else if (where == FORWARD_REMOTE) 655 return "admin remote"; 656 } else if (who == FORWARD_USER) { 657 if (where == FORWARD_LOCAL) 658 return "user local"; 659 else if (where == FORWARD_REMOTE) 660 return "user remote"; 661 } 662 fatal("Unknown forward permission list %d/%d", who, where); 663 } 664 665 /* Returns the forwarding permission list for the specified direction */ 666 static struct permission_set * 667 permission_set_get(struct ssh *ssh, int where) 668 { 669 struct ssh_channels *sc = ssh->chanctxt; 670 671 switch (where) { 672 case FORWARD_LOCAL: 673 return &sc->local_perms; 674 break; 675 case FORWARD_REMOTE: 676 return &sc->remote_perms; 677 break; 678 default: 679 fatal_f("invalid forwarding direction %d", where); 680 } 681 } 682 683 /* Returns pointers to the specified forwarding list and its element count */ 684 static void 685 permission_set_get_array(struct ssh *ssh, int who, int where, 686 struct permission ***permpp, u_int **npermpp) 687 { 688 struct permission_set *pset = permission_set_get(ssh, where); 689 690 switch (who) { 691 case FORWARD_USER: 692 *permpp = &pset->permitted_user; 693 *npermpp = &pset->num_permitted_user; 694 break; 695 case FORWARD_ADM: 696 *permpp = &pset->permitted_admin; 697 *npermpp = &pset->num_permitted_admin; 698 break; 699 default: 700 fatal_f("invalid forwarding client %d", who); 701 } 702 } 703 704 /* Adds an entry to the specified forwarding list */ 705 static int 706 permission_set_add(struct ssh *ssh, int who, int where, 707 const char *host_to_connect, int port_to_connect, 708 const char *listen_host, const char *listen_path, int listen_port, 709 Channel *downstream) 710 { 711 struct permission **permp; 712 u_int n, *npermp; 713 714 permission_set_get_array(ssh, who, where, &permp, &npermp); 715 716 if (*npermp >= INT_MAX) 717 fatal_f("%s overflow", fwd_ident(who, where)); 718 719 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 720 n = (*npermp)++; 721 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 722 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 723 (*permp)[n].port_to_connect = port_to_connect; 724 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 725 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 726 (*permp)[n].listen_port = listen_port; 727 (*permp)[n].downstream = downstream; 728 #undef MAYBE_DUP 729 return (int)n; 730 } 731 732 static void 733 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 734 { 735 struct ssh_channels *sc = ssh->chanctxt; 736 struct permission_set *pset = &sc->local_perms; 737 struct permission *perm; 738 int r; 739 u_int i; 740 741 for (i = 0; i < pset->num_permitted_user; i++) { 742 perm = &pset->permitted_user[i]; 743 if (perm->downstream != c) 744 continue; 745 746 /* cancel on the server, since mux client is gone */ 747 debug("channel %d: cleanup remote forward for %s:%u", 748 c->self, perm->listen_host, perm->listen_port); 749 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 750 (r = sshpkt_put_cstring(ssh, 751 "cancel-tcpip-forward")) != 0 || 752 (r = sshpkt_put_u8(ssh, 0)) != 0 || 753 (r = sshpkt_put_cstring(ssh, 754 channel_rfwd_bind_host(perm->listen_host))) != 0 || 755 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 756 (r = sshpkt_send(ssh)) != 0) { 757 fatal_fr(r, "channel %i", c->self); 758 } 759 fwd_perm_clear(perm); /* unregister */ 760 } 761 } 762 763 /* Free the channel and close its fd/socket. */ 764 void 765 channel_free(struct ssh *ssh, Channel *c) 766 { 767 struct ssh_channels *sc = ssh->chanctxt; 768 char *s; 769 u_int i, n; 770 Channel *other; 771 struct channel_confirm *cc; 772 773 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 774 if ((other = sc->channels[i]) == NULL) 775 continue; 776 n++; 777 /* detach from mux client and prepare for closing */ 778 if (c->type == SSH_CHANNEL_MUX_CLIENT && 779 other->type == SSH_CHANNEL_MUX_PROXY && 780 other->mux_ctx == c) { 781 other->mux_ctx = NULL; 782 other->type = SSH_CHANNEL_OPEN; 783 other->istate = CHAN_INPUT_CLOSED; 784 other->ostate = CHAN_OUTPUT_CLOSED; 785 } 786 } 787 debug("channel %d: free: %s, nchannels %u", c->self, 788 c->remote_name ? c->remote_name : "???", n); 789 790 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 791 mux_remove_remote_forwardings(ssh, c); 792 free(c->mux_ctx); 793 c->mux_ctx = NULL; 794 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 795 free(c->mux_ctx); 796 c->mux_ctx = NULL; 797 } 798 799 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 800 s = channel_open_message(ssh); 801 debug3("channel %d: status: %s", c->self, s); 802 free(s); 803 } 804 805 channel_close_fds(ssh, c); 806 sshbuf_free(c->input); 807 sshbuf_free(c->output); 808 sshbuf_free(c->extended); 809 c->input = c->output = c->extended = NULL; 810 free(c->remote_name); 811 c->remote_name = NULL; 812 free(c->path); 813 c->path = NULL; 814 free(c->listening_addr); 815 c->listening_addr = NULL; 816 free(c->xctype); 817 c->xctype = NULL; 818 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 819 if (cc->abandon_cb != NULL) 820 cc->abandon_cb(ssh, c, cc->ctx); 821 TAILQ_REMOVE(&c->status_confirms, cc, entry); 822 freezero(cc, sizeof(*cc)); 823 } 824 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 825 c->filter_cleanup(ssh, c->self, c->filter_ctx); 826 sc->channels[c->self] = NULL; 827 freezero(c, sizeof(*c)); 828 } 829 830 void 831 channel_free_all(struct ssh *ssh) 832 { 833 u_int i; 834 struct ssh_channels *sc = ssh->chanctxt; 835 836 for (i = 0; i < sc->channels_alloc; i++) 837 if (sc->channels[i] != NULL) 838 channel_free(ssh, sc->channels[i]); 839 840 free(sc->channels); 841 sc->channels = NULL; 842 sc->channels_alloc = 0; 843 844 free(sc->x11_saved_display); 845 sc->x11_saved_display = NULL; 846 847 free(sc->x11_saved_proto); 848 sc->x11_saved_proto = NULL; 849 850 free(sc->x11_saved_data); 851 sc->x11_saved_data = NULL; 852 sc->x11_saved_data_len = 0; 853 854 free(sc->x11_fake_data); 855 sc->x11_fake_data = NULL; 856 sc->x11_fake_data_len = 0; 857 } 858 859 void 860 channel_free_channels(struct ssh *ssh) 861 { 862 struct ssh_channels *sc; 863 864 if (ssh == NULL || ssh->chanctxt == NULL) 865 return; 866 channel_free_all(ssh); 867 channel_clear_permission(ssh, FORWARD_USER, FORWARD_LOCAL); 868 channel_clear_permission(ssh, FORWARD_USER, FORWARD_REMOTE); 869 channel_clear_permission(ssh, FORWARD_ADM, FORWARD_LOCAL); 870 channel_clear_permission(ssh, FORWARD_ADM, FORWARD_REMOTE); 871 sc = ssh->chanctxt; 872 free(sc->bulk_classifier_tty); 873 free(sc->bulk_classifier_notty); 874 free(sc->channel_pre); 875 free(sc->channel_post); 876 freezero(sc, sizeof(*sc)); 877 ssh->chanctxt = NULL; 878 } 879 880 /* 881 * Closes the sockets/fds of all channels. This is used to close extra file 882 * descriptors after a fork. 883 */ 884 void 885 channel_close_all(struct ssh *ssh) 886 { 887 u_int i; 888 889 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 890 if (ssh->chanctxt->channels[i] != NULL) 891 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 892 } 893 894 /* 895 * Stop listening to channels. 896 */ 897 void 898 channel_stop_listening(struct ssh *ssh) 899 { 900 u_int i; 901 Channel *c; 902 903 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 904 c = ssh->chanctxt->channels[i]; 905 if (c != NULL) { 906 switch (c->type) { 907 case SSH_CHANNEL_AUTH_SOCKET: 908 case SSH_CHANNEL_PORT_LISTENER: 909 case SSH_CHANNEL_RPORT_LISTENER: 910 case SSH_CHANNEL_X11_LISTENER: 911 case SSH_CHANNEL_UNIX_LISTENER: 912 case SSH_CHANNEL_RUNIX_LISTENER: 913 channel_close_fd(ssh, c, &c->sock); 914 channel_free(ssh, c); 915 break; 916 } 917 } 918 } 919 } 920 921 /* 922 * Returns true if no channel has too much buffered data, and false if one or 923 * more channel is overfull. 924 */ 925 int 926 channel_not_very_much_buffered_data(struct ssh *ssh) 927 { 928 u_int i; 929 u_int maxsize = ssh_packet_get_maxsize(ssh); 930 Channel *c; 931 932 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 933 c = ssh->chanctxt->channels[i]; 934 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 935 continue; 936 if (sshbuf_len(c->output) > maxsize) { 937 debug2("channel %d: big output buffer %zu > %u", 938 c->self, sshbuf_len(c->output), maxsize); 939 return 0; 940 } 941 } 942 return 1; 943 } 944 945 /* Returns true if any channel is still open. */ 946 int 947 channel_still_open(struct ssh *ssh) 948 { 949 u_int i; 950 Channel *c; 951 952 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 953 c = ssh->chanctxt->channels[i]; 954 if (c == NULL) 955 continue; 956 switch (c->type) { 957 case SSH_CHANNEL_X11_LISTENER: 958 case SSH_CHANNEL_PORT_LISTENER: 959 case SSH_CHANNEL_RPORT_LISTENER: 960 case SSH_CHANNEL_MUX_LISTENER: 961 case SSH_CHANNEL_CLOSED: 962 case SSH_CHANNEL_AUTH_SOCKET: 963 case SSH_CHANNEL_DYNAMIC: 964 case SSH_CHANNEL_RDYNAMIC_OPEN: 965 case SSH_CHANNEL_CONNECTING: 966 case SSH_CHANNEL_ZOMBIE: 967 case SSH_CHANNEL_ABANDONED: 968 case SSH_CHANNEL_UNIX_LISTENER: 969 case SSH_CHANNEL_RUNIX_LISTENER: 970 continue; 971 case SSH_CHANNEL_LARVAL: 972 continue; 973 case SSH_CHANNEL_OPENING: 974 case SSH_CHANNEL_OPEN: 975 case SSH_CHANNEL_RDYNAMIC_FINISH: 976 case SSH_CHANNEL_X11_OPEN: 977 case SSH_CHANNEL_MUX_CLIENT: 978 case SSH_CHANNEL_MUX_PROXY: 979 return 1; 980 default: 981 fatal_f("bad channel type %d", c->type); 982 /* NOTREACHED */ 983 } 984 } 985 return 0; 986 } 987 988 /* Returns true if a channel with a TTY is open. */ 989 int 990 channel_tty_open(struct ssh *ssh) 991 { 992 u_int i; 993 Channel *c; 994 995 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 996 c = ssh->chanctxt->channels[i]; 997 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 998 continue; 999 if (c->client_tty) 1000 return 1; 1001 } 1002 return 0; 1003 } 1004 1005 /* Returns the id of an open channel suitable for keepaliving */ 1006 int 1007 channel_find_open(struct ssh *ssh) 1008 { 1009 u_int i; 1010 Channel *c; 1011 1012 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1013 c = ssh->chanctxt->channels[i]; 1014 if (c == NULL || !c->have_remote_id) 1015 continue; 1016 switch (c->type) { 1017 case SSH_CHANNEL_CLOSED: 1018 case SSH_CHANNEL_DYNAMIC: 1019 case SSH_CHANNEL_RDYNAMIC_OPEN: 1020 case SSH_CHANNEL_RDYNAMIC_FINISH: 1021 case SSH_CHANNEL_X11_LISTENER: 1022 case SSH_CHANNEL_PORT_LISTENER: 1023 case SSH_CHANNEL_RPORT_LISTENER: 1024 case SSH_CHANNEL_MUX_LISTENER: 1025 case SSH_CHANNEL_MUX_CLIENT: 1026 case SSH_CHANNEL_MUX_PROXY: 1027 case SSH_CHANNEL_OPENING: 1028 case SSH_CHANNEL_CONNECTING: 1029 case SSH_CHANNEL_ZOMBIE: 1030 case SSH_CHANNEL_ABANDONED: 1031 case SSH_CHANNEL_UNIX_LISTENER: 1032 case SSH_CHANNEL_RUNIX_LISTENER: 1033 continue; 1034 case SSH_CHANNEL_LARVAL: 1035 case SSH_CHANNEL_AUTH_SOCKET: 1036 case SSH_CHANNEL_OPEN: 1037 case SSH_CHANNEL_X11_OPEN: 1038 return i; 1039 default: 1040 fatal_f("bad channel type %d", c->type); 1041 /* NOTREACHED */ 1042 } 1043 } 1044 return -1; 1045 } 1046 1047 /* Returns the state of the channel's extended usage flag */ 1048 const char * 1049 channel_format_extended_usage(const Channel *c) 1050 { 1051 if (c->efd == -1) 1052 return "closed"; 1053 1054 switch (c->extended_usage) { 1055 case CHAN_EXTENDED_WRITE: 1056 return "write"; 1057 case CHAN_EXTENDED_READ: 1058 return "read"; 1059 case CHAN_EXTENDED_IGNORE: 1060 return "ignore"; 1061 default: 1062 return "UNKNOWN"; 1063 } 1064 } 1065 1066 static char * 1067 channel_format_status(const Channel *c) 1068 { 1069 char *ret = NULL; 1070 1071 xasprintf(&ret, "t%d [%s] %s%u %s%u i%u/%zu o%u/%zu e[%s]/%zu " 1072 "fd %d/%d/%d sock %d cc %d %s%u io 0x%02x/0x%02x %s%s", 1073 c->type, c->xctype != NULL ? c->xctype : c->ctype, 1074 c->have_remote_id ? "r" : "nr", c->remote_id, 1075 c->mux_ctx != NULL ? "m" : "nm", c->mux_downstream_id, 1076 c->istate, sshbuf_len(c->input), 1077 c->ostate, sshbuf_len(c->output), 1078 channel_format_extended_usage(c), sshbuf_len(c->extended), 1079 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 1080 c->have_ctl_child_id ? "c" : "nc", c->ctl_child_id, 1081 c->io_want, c->io_ready, 1082 c->isatty ? "T" : (c->remote_has_tty ? "RT" : ""), 1083 c->bulk ? "B" : "I"); 1084 return ret; 1085 } 1086 1087 /* 1088 * Returns a message describing the currently open forwarded connections, 1089 * suitable for sending to the client. The message contains crlf pairs for 1090 * newlines. 1091 */ 1092 char * 1093 channel_open_message(struct ssh *ssh) 1094 { 1095 struct sshbuf *buf; 1096 Channel *c; 1097 u_int i; 1098 int r; 1099 char *cp, *ret; 1100 1101 if ((buf = sshbuf_new()) == NULL) 1102 fatal_f("sshbuf_new"); 1103 if ((r = sshbuf_putf(buf, 1104 "The following connections are open:\r\n")) != 0) 1105 fatal_fr(r, "sshbuf_putf"); 1106 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 1107 c = ssh->chanctxt->channels[i]; 1108 if (c == NULL) 1109 continue; 1110 switch (c->type) { 1111 case SSH_CHANNEL_X11_LISTENER: 1112 case SSH_CHANNEL_PORT_LISTENER: 1113 case SSH_CHANNEL_RPORT_LISTENER: 1114 case SSH_CHANNEL_CLOSED: 1115 case SSH_CHANNEL_AUTH_SOCKET: 1116 case SSH_CHANNEL_ZOMBIE: 1117 case SSH_CHANNEL_ABANDONED: 1118 case SSH_CHANNEL_MUX_LISTENER: 1119 case SSH_CHANNEL_UNIX_LISTENER: 1120 case SSH_CHANNEL_RUNIX_LISTENER: 1121 continue; 1122 case SSH_CHANNEL_LARVAL: 1123 case SSH_CHANNEL_OPENING: 1124 case SSH_CHANNEL_CONNECTING: 1125 case SSH_CHANNEL_DYNAMIC: 1126 case SSH_CHANNEL_RDYNAMIC_OPEN: 1127 case SSH_CHANNEL_RDYNAMIC_FINISH: 1128 case SSH_CHANNEL_OPEN: 1129 case SSH_CHANNEL_X11_OPEN: 1130 case SSH_CHANNEL_MUX_PROXY: 1131 case SSH_CHANNEL_MUX_CLIENT: 1132 cp = channel_format_status(c); 1133 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 1134 c->self, c->remote_name, cp)) != 0) { 1135 free(cp); 1136 fatal_fr(r, "sshbuf_putf"); 1137 } 1138 free(cp); 1139 continue; 1140 default: 1141 fatal_f("bad channel type %d", c->type); 1142 /* NOTREACHED */ 1143 } 1144 } 1145 if ((ret = sshbuf_dup_string(buf)) == NULL) 1146 fatal_f("sshbuf_dup_string"); 1147 sshbuf_free(buf); 1148 return ret; 1149 } 1150 1151 void 1152 channel_report_open(struct ssh *ssh, int level) 1153 { 1154 char *open, *oopen, *cp, ident[256]; 1155 1156 sshpkt_fmt_connection_id(ssh, ident, sizeof(ident)); 1157 do_log2(level, "Connection: %s (pid %ld)", ident, (long)getpid()); 1158 open = oopen = channel_open_message(ssh); 1159 while ((cp = strsep(&open, "\r\n")) != NULL) { 1160 if (*cp != '\0') 1161 do_log2(level, "%s", cp); 1162 } 1163 free(oopen); 1164 } 1165 1166 static void 1167 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 1168 { 1169 int r; 1170 1171 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1172 (r = sshpkt_put_cstring(ssh, type)) != 0 || 1173 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1174 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1175 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 1176 fatal_r(r, "%s: channel %i: open", where, c->self); 1177 } 1178 } 1179 1180 void 1181 channel_send_open(struct ssh *ssh, int id) 1182 { 1183 Channel *c = channel_lookup(ssh, id); 1184 int r; 1185 1186 if (c == NULL) { 1187 logit("channel_send_open: %d: bad id", id); 1188 return; 1189 } 1190 debug2("channel %d: send open", id); 1191 open_preamble(ssh, __func__, c, c->ctype); 1192 if ((r = sshpkt_send(ssh)) != 0) 1193 fatal_fr(r, "channel %i", c->self); 1194 } 1195 1196 void 1197 channel_request_start(struct ssh *ssh, int id, const char *service, 1198 int wantconfirm) 1199 { 1200 Channel *c = channel_lookup(ssh, id); 1201 int r; 1202 1203 if (c == NULL) { 1204 logit_f("%d: unknown channel id", id); 1205 return; 1206 } 1207 if (!c->have_remote_id) 1208 fatal_f("channel %d: no remote id", c->self); 1209 1210 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 1211 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 1212 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1213 (r = sshpkt_put_cstring(ssh, service)) != 0 || 1214 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 1215 fatal_fr(r, "channel %i", c->self); 1216 } 1217 } 1218 1219 void 1220 channel_register_status_confirm(struct ssh *ssh, int id, 1221 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1222 { 1223 struct channel_confirm *cc; 1224 Channel *c; 1225 1226 if ((c = channel_lookup(ssh, id)) == NULL) 1227 fatal_f("%d: bad id", id); 1228 1229 cc = xcalloc(1, sizeof(*cc)); 1230 cc->cb = cb; 1231 cc->abandon_cb = abandon_cb; 1232 cc->ctx = ctx; 1233 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1234 } 1235 1236 void 1237 channel_register_open_confirm(struct ssh *ssh, int id, 1238 channel_open_fn *fn, void *ctx) 1239 { 1240 Channel *c = channel_lookup(ssh, id); 1241 1242 if (c == NULL) { 1243 logit_f("%d: bad id", id); 1244 return; 1245 } 1246 c->open_confirm = fn; 1247 c->open_confirm_ctx = ctx; 1248 } 1249 1250 void 1251 channel_register_cleanup(struct ssh *ssh, int id, 1252 channel_callback_fn *fn, int do_close) 1253 { 1254 Channel *c = channel_by_id(ssh, id); 1255 1256 if (c == NULL) { 1257 logit_f("%d: bad id", id); 1258 return; 1259 } 1260 c->detach_user = fn; 1261 c->detach_close = do_close; 1262 } 1263 1264 void 1265 channel_cancel_cleanup(struct ssh *ssh, int id) 1266 { 1267 Channel *c = channel_by_id(ssh, id); 1268 1269 if (c == NULL) { 1270 logit_f("%d: bad id", id); 1271 return; 1272 } 1273 c->detach_user = NULL; 1274 c->detach_close = 0; 1275 } 1276 1277 void 1278 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1279 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1280 { 1281 Channel *c = channel_lookup(ssh, id); 1282 1283 if (c == NULL) { 1284 logit_f("%d: bad id", id); 1285 return; 1286 } 1287 c->input_filter = ifn; 1288 c->output_filter = ofn; 1289 c->filter_ctx = ctx; 1290 c->filter_cleanup = cfn; 1291 } 1292 1293 void 1294 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1295 int extusage, int nonblock, int is_tty, u_int window_max) 1296 { 1297 Channel *c = channel_lookup(ssh, id); 1298 int r; 1299 1300 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1301 fatal("channel_activate for non-larval channel %d.", id); 1302 if (!c->have_remote_id) 1303 fatal_f("channel %d: no remote id", c->self); 1304 1305 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1306 c->type = SSH_CHANNEL_OPEN; 1307 channel_set_used_time(ssh, c); 1308 c->local_window = c->local_window_max = window_max; 1309 1310 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1311 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1312 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1313 (r = sshpkt_send(ssh)) != 0) 1314 fatal_fr(r, "channel %i", c->self); 1315 } 1316 1317 static void 1318 channel_pre_listener(struct ssh *ssh, Channel *c) 1319 { 1320 c->io_want = SSH_CHAN_IO_SOCK_R; 1321 } 1322 1323 static void 1324 channel_pre_connecting(struct ssh *ssh, Channel *c) 1325 { 1326 debug3("channel %d: waiting for connection", c->self); 1327 c->io_want = SSH_CHAN_IO_SOCK_W; 1328 } 1329 1330 static void 1331 channel_pre_open(struct ssh *ssh, Channel *c) 1332 { 1333 c->io_want = 0; 1334 if (c->istate == CHAN_INPUT_OPEN && 1335 c->remote_window > 0 && 1336 sshbuf_len(c->input) < c->remote_window && 1337 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1338 c->io_want |= SSH_CHAN_IO_RFD; 1339 if (c->ostate == CHAN_OUTPUT_OPEN || 1340 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1341 if (sshbuf_len(c->output) > 0) { 1342 c->io_want |= SSH_CHAN_IO_WFD; 1343 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1344 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1345 debug2("channel %d: " 1346 "obuf_empty delayed efd %d/(%zu)", c->self, 1347 c->efd, sshbuf_len(c->extended)); 1348 else 1349 chan_obuf_empty(ssh, c); 1350 } 1351 } 1352 /** XXX check close conditions, too */ 1353 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1354 c->ostate == CHAN_OUTPUT_CLOSED)) { 1355 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1356 sshbuf_len(c->extended) > 0) 1357 c->io_want |= SSH_CHAN_IO_EFD_W; 1358 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1359 (c->extended_usage == CHAN_EXTENDED_READ || 1360 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1361 sshbuf_len(c->extended) < c->remote_window) 1362 c->io_want |= SSH_CHAN_IO_EFD_R; 1363 } 1364 /* XXX: What about efd? races? */ 1365 } 1366 1367 /* 1368 * This is a special state for X11 authentication spoofing. An opened X11 1369 * connection (when authentication spoofing is being done) remains in this 1370 * state until the first packet has been completely read. The authentication 1371 * data in that packet is then substituted by the real data if it matches the 1372 * fake data, and the channel is put into normal mode. 1373 * XXX All this happens at the client side. 1374 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1375 */ 1376 static int 1377 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1378 { 1379 struct ssh_channels *sc = ssh->chanctxt; 1380 u_char *ucp; 1381 u_int proto_len, data_len; 1382 1383 if (sc->x11_saved_proto == NULL) { 1384 error("X11 forwarding opened before X11 forwarding requested"); 1385 return -1; 1386 } 1387 1388 /* Is this being called after the refusal deadline? */ 1389 if (sc->x11_refuse_time != 0 && 1390 monotime() >= sc->x11_refuse_time) { 1391 verbose("Rejected X11 connection after ForwardX11Timeout " 1392 "expired"); 1393 return -1; 1394 } 1395 1396 /* Check if the fixed size part of the packet is in buffer. */ 1397 if (sshbuf_len(b) < 12) 1398 return 0; 1399 1400 /* Parse the lengths of variable-length fields. */ 1401 ucp = sshbuf_mutable_ptr(b); 1402 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1403 proto_len = 256 * ucp[6] + ucp[7]; 1404 data_len = 256 * ucp[8] + ucp[9]; 1405 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1406 proto_len = ucp[6] + 256 * ucp[7]; 1407 data_len = ucp[8] + 256 * ucp[9]; 1408 } else { 1409 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1410 ucp[0]); 1411 return -1; 1412 } 1413 1414 /* Check if the whole packet is in buffer. */ 1415 if (sshbuf_len(b) < 1416 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1417 return 0; 1418 1419 /* Check if authentication protocol matches. */ 1420 if (proto_len != strlen(sc->x11_saved_proto) || 1421 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1422 debug2("X11 connection uses different authentication protocol."); 1423 return -1; 1424 } 1425 /* Check if authentication data matches our fake data. */ 1426 if (data_len != sc->x11_fake_data_len || 1427 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1428 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1429 debug2("X11 auth data does not match fake data."); 1430 return -1; 1431 } 1432 /* Check fake data length */ 1433 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1434 error("X11 fake_data_len %d != saved_data_len %d", 1435 sc->x11_fake_data_len, sc->x11_saved_data_len); 1436 return -1; 1437 } 1438 /* 1439 * Received authentication protocol and data match 1440 * our fake data. Substitute the fake data with real 1441 * data. 1442 */ 1443 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1444 sc->x11_saved_data, sc->x11_saved_data_len); 1445 return 1; 1446 } 1447 1448 void 1449 channel_force_close(struct ssh *ssh, Channel *c, int abandon) 1450 { 1451 debug3_f("channel %d: forcibly closing", c->self); 1452 if (c->istate == CHAN_INPUT_OPEN) 1453 chan_read_failed(ssh, c); 1454 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1455 sshbuf_reset(c->input); 1456 chan_ibuf_empty(ssh, c); 1457 } 1458 if (c->ostate == CHAN_OUTPUT_OPEN || 1459 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1460 sshbuf_reset(c->output); 1461 chan_write_failed(ssh, c); 1462 } 1463 if (c->detach_user) 1464 c->detach_user(ssh, c->self, 1, NULL); 1465 if (c->efd != -1) 1466 channel_close_fd(ssh, c, &c->efd); 1467 if (abandon) 1468 c->type = SSH_CHANNEL_ABANDONED; 1469 /* exempt from inactivity timeouts */ 1470 c->inactive_deadline = 0; 1471 c->lastused = 0; 1472 } 1473 1474 static void 1475 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1476 { 1477 int ret = x11_open_helper(ssh, c->output); 1478 1479 /* c->force_drain = 1; */ 1480 1481 if (ret == 1) { 1482 c->type = SSH_CHANNEL_OPEN; 1483 channel_set_used_time(ssh, c); 1484 channel_pre_open(ssh, c); 1485 } else if (ret == -1) { 1486 logit("X11 connection rejected because of wrong " 1487 "authentication."); 1488 debug2("X11 rejected %d i%d/o%d", 1489 c->self, c->istate, c->ostate); 1490 channel_force_close(ssh, c, 0); 1491 } 1492 } 1493 1494 static void 1495 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1496 { 1497 c->io_want = 0; 1498 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1499 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1500 c->io_want |= SSH_CHAN_IO_RFD; 1501 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1502 /* clear buffer immediately (discard any partial packet) */ 1503 sshbuf_reset(c->input); 1504 chan_ibuf_empty(ssh, c); 1505 /* Start output drain. XXX just kill chan? */ 1506 chan_rcvd_oclose(ssh, c); 1507 } 1508 if (c->ostate == CHAN_OUTPUT_OPEN || 1509 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1510 if (sshbuf_len(c->output) > 0) 1511 c->io_want |= SSH_CHAN_IO_WFD; 1512 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1513 chan_obuf_empty(ssh, c); 1514 } 1515 } 1516 1517 static inline int 1518 socks_decode_error(Channel *c, int status, const char *func, const char *msg) 1519 { 1520 if (status == SSH_ERR_MESSAGE_INCOMPLETE) 1521 return 0; 1522 else { 1523 debug_r(status, "%s: channel %d: decode %s", 1524 func, c->self, msg); 1525 return -1; 1526 } 1527 } 1528 1529 /* try to decode a socks4 header */ 1530 static int 1531 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1532 { 1533 uint8_t socks_ver, socks_cmd, dest_addr[4]; 1534 uint16_t dest_port; 1535 char *user = NULL, *host = NULL; 1536 int success = -1, socks4a = 0, r; 1537 struct sshbuf *b = NULL; 1538 1539 if (sshbuf_len(input) < 9) 1540 return 0; 1541 1542 /* We may not have a complete message, so work on a dup of the buffer */ 1543 if ((b = sshbuf_fromb(input)) == NULL) 1544 fatal_f("sshbuf_fromb failed"); 1545 1546 debug2("channel %d: decode socks4", c->self); 1547 if ((r = sshbuf_get_u8(b, &socks_ver)) != 0 || 1548 (r = sshbuf_get_u8(b, &socks_cmd)) != 0 || 1549 (r = sshbuf_get_u16(b, &dest_port)) != 0 || 1550 (r = sshbuf_get(b, &dest_addr, sizeof(dest_addr))) != 0 || 1551 (r = sshbuf_get_nulterminated_string(b, 1024, &user, NULL)) != 0) { 1552 success = socks_decode_error(c, r, __func__, "header"); 1553 goto out; 1554 } 1555 1556 /* Is this a SOCKS4A request? (indicated by an address of 0.0.0.x) */ 1557 if (dest_addr[0] == 0 && dest_addr[1] == 0 && 1558 dest_addr[2] == 0 && dest_addr[3] != 0) { 1559 /* If so, then the hostname follows, also nul-terminated */ 1560 if ((r = sshbuf_get_nulterminated_string(b, 1024, 1561 &host, NULL)) != 0) { 1562 success = socks_decode_error(c, r, __func__, "host"); 1563 goto out; 1564 } 1565 socks4a = 1; 1566 } else { 1567 /* Plain SOCKS4 passes an IPv4 binary address; reconstruct */ 1568 xasprintf(&host, "%d.%d.%d.%d", 1569 dest_addr[0], dest_addr[1], dest_addr[2], dest_addr[3]); 1570 } 1571 1572 /* We have a complete SOCKS4 message; consume it from input */ 1573 if ((r = sshbuf_consume_upto_child(input, b)) != 0) 1574 fatal_fr(r, "channel %d: consume", c->self); 1575 1576 /* Handle the request */ 1577 debug2("channel %d: %s: user=\"%s\" command=%d destination=[%s]:%d", 1578 c->self, socks4a ? "SOCKS4A" : "SOCKS4", user, (int)socks_cmd, 1579 host, dest_port); 1580 if (socks_cmd != 1) { 1581 debug("channel %d: cannot handle %s command 0x%02x", 1582 c->self, socks4a ? "SOCKS4A" : "SOCKS4", socks_cmd); 1583 goto out; 1584 } 1585 free(c->path); 1586 c->path = host; 1587 host = NULL; /* transferred */ 1588 c->host_port = dest_port; 1589 1590 /* Reply to the SOCKS4 client */ 1591 if ((r = sshbuf_put_u8(output, 0)) != 0 || /* vn: 0 for reply */ 1592 (r = sshbuf_put_u8(output, 90)) != 0 || /* cd: req granted */ 1593 (r = sshbuf_put_u16(output, 0)) != 0 || /* port: ignored */ 1594 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0) /* ignored */ 1595 fatal_fr(r, "channel %d: compose reply", c->self); 1596 1597 /* success */ 1598 success = 1; 1599 out: 1600 sshbuf_free(b); 1601 free(user); 1602 free(host); 1603 return success; 1604 } 1605 1606 /* try to decode a socks5 header */ 1607 #define SSH_SOCKS5_AUTHDONE 0x1000 1608 #define SSH_SOCKS5_NOAUTH 0x00 1609 #define SSH_SOCKS5_IPV4 0x01 1610 #define SSH_SOCKS5_DOMAIN 0x03 1611 #define SSH_SOCKS5_IPV6 0x04 1612 #define SSH_SOCKS5_CONNECT 0x01 1613 #define SSH_SOCKS5_SUCCESS 0x00 1614 1615 /* 1616 * Handles SOCKS5 authentication. Note 'b' must be a dup of 'input' 1617 * Returns 0 on insufficient queued date, 1 on authentication success or 1618 * -1 on error. 1619 */ 1620 static int 1621 channel_socks5_check_auth(Channel *c, struct sshbuf *b, struct sshbuf *input, 1622 struct sshbuf *output) 1623 { 1624 uint8_t socks_ver; 1625 uint8_t nmethods, method; 1626 int r; 1627 u_int i, found; 1628 1629 /* format: ver | nmethods | methods */ 1630 if ((r = sshbuf_get_u8(b, &socks_ver)) != 0) 1631 return socks_decode_error(c, r, __func__, "version"); 1632 if (socks_ver != 5) /* shouldn't happen; checked by caller^2 */ 1633 fatal_fr(r, "channel %d: internal error: not socks5", c->self); 1634 if ((r = sshbuf_get_u8(b, &nmethods)) != 0) 1635 return socks_decode_error(c, r, __func__, "methods"); 1636 for (found = i = 0; i < nmethods; i++) { 1637 if ((r = sshbuf_get_u8(b, &method)) != 0) 1638 return socks_decode_error(c, r, __func__, "method"); 1639 if (method == SSH_SOCKS5_NOAUTH) 1640 found = 1; 1641 } 1642 if (!found) { 1643 debug("channel %d: didn't request SSH_SOCKS5_NOAUTH", c->self); 1644 return -1; 1645 } 1646 /* Consume completed request */ 1647 if ((r = sshbuf_consume_upto_child(input, b)) != 0) 1648 fatal_fr(r, "channel %d: consume", c->self); 1649 1650 /* Compose reply: version, method */ 1651 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1652 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1653 fatal_fr(r, "channel %d: append reply", c->self); 1654 /* success */ 1655 debug2("channel %d: socks5 auth done", c->self); 1656 return 1; 1657 } 1658 1659 static int 1660 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1661 { 1662 uint8_t socks_ver, socks_cmd, socks_reserved, socks_atyp, addrlen; 1663 uint16_t dest_port; 1664 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1665 u_int af; 1666 int r, success = -1;; 1667 struct sshbuf *b = NULL; 1668 1669 debug2("channel %d: decode socks5 %s", c->self, 1670 (c->flags & SSH_SOCKS5_AUTHDONE) ? "request" : "auth"); 1671 1672 /* We may not have a complete message, so work on a dup of the buffer */ 1673 if ((b = sshbuf_fromb(input)) == NULL) 1674 fatal_f("sshbuf_fromb failed"); 1675 1676 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1677 if ((r = channel_socks5_check_auth(c, b, input, output)) != 1) { 1678 success = r; 1679 goto out; 1680 } 1681 c->flags |= SSH_SOCKS5_AUTHDONE; 1682 /* Continue to parse request in case client speculated ahead */ 1683 } 1684 1685 /* Request messages (auth or connect) always start with the version */ 1686 if ((r = sshbuf_get_u8(b, &socks_ver)) != 0) { 1687 success = socks_decode_error(c, r, __func__, "version"); 1688 goto out; 1689 } 1690 if (socks_ver != 5) /* shouldn't happen */ 1691 fatal_fr(r, "channel %d: internal error: not socks5", c->self); 1692 1693 /* Parse SOCKS5 request header */ 1694 debug2("channel %d: socks5 post auth", c->self); 1695 if ((r = sshbuf_get_u8(b, &socks_cmd)) != 0 || 1696 (r = sshbuf_get_u8(b, &socks_reserved)) != 0 || 1697 (r = sshbuf_get_u8(b, &socks_atyp)) != 0) { 1698 success = socks_decode_error(c, r, __func__, "request header"); 1699 goto out; 1700 } 1701 1702 if (socks_ver != 0x05 || 1703 socks_cmd != SSH_SOCKS5_CONNECT || 1704 socks_reserved != 0x00) { 1705 debug2("channel %d: only socks5 connect supported", c->self); 1706 goto out; 1707 } 1708 1709 switch (socks_atyp) { 1710 case SSH_SOCKS5_IPV4: 1711 addrlen = 4; 1712 af = AF_INET; 1713 break; 1714 case SSH_SOCKS5_DOMAIN: 1715 if ((r = sshbuf_get_u8(b, &addrlen)) != 0) { 1716 success = socks_decode_error(c, r, __func__, "addrlen"); 1717 goto out; 1718 } 1719 af = -1; 1720 break; 1721 case SSH_SOCKS5_IPV6: 1722 addrlen = 16; 1723 af = AF_INET6; 1724 break; 1725 default: 1726 debug2("channel %d: bad socks5 atyp %d", c->self, socks_atyp); 1727 goto out; 1728 } 1729 if ((r = sshbuf_get(b, &dest_addr, addrlen)) != 0 || 1730 (r = sshbuf_get_u16(b, &dest_port)) != 0) { 1731 success = socks_decode_error(c, r, __func__, "addr/port"); 1732 goto out; 1733 } 1734 dest_addr[addrlen] = '\0'; 1735 1736 /* We have a complete SOCKS5 request; consume it from input */ 1737 if ((r = sshbuf_consume_upto_child(input, b)) != 0) 1738 fatal_fr(r, "channel %d: consume", c->self); 1739 1740 free(c->path); 1741 c->path = NULL; 1742 if (socks_atyp == SSH_SOCKS5_DOMAIN) 1743 c->path = xstrdup(dest_addr); 1744 else { 1745 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1746 return -1; 1747 c->path = xstrdup(ntop); 1748 } 1749 c->host_port = dest_port; 1750 1751 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1752 c->self, c->path, c->host_port, socks_cmd); 1753 1754 /* Reply */ 1755 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || /* version */ 1756 (r = sshbuf_put_u8(output, SSH_SOCKS5_SUCCESS)) != 0 || /* cmd */ 1757 (r = sshbuf_put_u8(output, 0)) != 0 || /* reserved, ignored */ 1758 (r = sshbuf_put_u8(output, SSH_SOCKS5_IPV4)) != 0 || /* addrtype */ 1759 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || /* addr */ 1760 (r = sshbuf_put_u16(output, dest_port)) != 0) /* port */ 1761 fatal_fr(r, "channel %d: append reply", c->self); 1762 1763 /* success */ 1764 success = 1; 1765 out: 1766 sshbuf_free(b); 1767 return success; 1768 } 1769 1770 Channel * 1771 channel_connect_stdio_fwd(struct ssh *ssh, 1772 const char *host_to_connect, int port_to_connect, 1773 int in, int out, int nonblock) 1774 { 1775 Channel *c; 1776 1777 debug_f("%s:%d", host_to_connect, port_to_connect); 1778 1779 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1780 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1781 0, "stdio-forward", nonblock); 1782 1783 c->path = xstrdup(host_to_connect); 1784 c->host_port = port_to_connect; 1785 c->listening_port = 0; 1786 c->force_drain = 1; 1787 1788 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1789 port_open_helper(ssh, c, port_to_connect == PORT_STREAMLOCAL ? 1790 "direct-streamlocal@openssh.com" : "direct-tcpip"); 1791 1792 return c; 1793 } 1794 1795 /* dynamic port forwarding */ 1796 static void 1797 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1798 { 1799 u_int have; 1800 u_char ver; 1801 int r, ret; 1802 1803 c->io_want = 0; 1804 have = sshbuf_len(c->input); 1805 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1806 /* sshbuf_dump(c->input, stderr); */ 1807 /* check if the fixed size part of the packet is in buffer. */ 1808 if (have < 3) { 1809 /* need more */ 1810 c->io_want |= SSH_CHAN_IO_RFD; 1811 return; 1812 } 1813 /* try to guess the protocol */ 1814 if ((r = sshbuf_peek_u8(c->input, 0, &ver)) != 0) 1815 fatal_fr(r, "sshbuf_peek_u8"); 1816 switch (ver) { 1817 case 0x04: 1818 ret = channel_decode_socks4(c, c->input, c->output); 1819 break; 1820 case 0x05: 1821 ret = channel_decode_socks5(c, c->input, c->output); 1822 break; 1823 default: 1824 debug2_f("channel %d: unknown SOCKS version %u", c->self, ver); 1825 ret = -1; 1826 break; 1827 } 1828 if (ret < 0) { 1829 chan_mark_dead(ssh, c); 1830 } else if (ret == 0) { 1831 debug2("channel %d: pre_dynamic: need more", c->self); 1832 /* need more */ 1833 c->io_want |= SSH_CHAN_IO_RFD; 1834 if (sshbuf_len(c->output)) 1835 c->io_want |= SSH_CHAN_IO_WFD; 1836 } else { 1837 /* switch to the next state */ 1838 c->type = SSH_CHANNEL_OPENING; 1839 port_open_helper(ssh, c, "direct-tcpip"); 1840 } 1841 } 1842 1843 /* simulate read-error */ 1844 static void 1845 rdynamic_close(struct ssh *ssh, Channel *c) 1846 { 1847 c->type = SSH_CHANNEL_OPEN; 1848 channel_force_close(ssh, c, 0); 1849 } 1850 1851 /* reverse dynamic port forwarding */ 1852 static void 1853 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1854 { 1855 const u_char *p; 1856 u_int have, len; 1857 int r, ret; 1858 1859 have = sshbuf_len(c->output); 1860 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1861 /* sshbuf_dump(c->output, stderr); */ 1862 /* EOF received */ 1863 if (c->flags & CHAN_EOF_RCVD) { 1864 if ((r = sshbuf_consume(c->output, have)) != 0) 1865 fatal_fr(r, "channel %d: consume", c->self); 1866 rdynamic_close(ssh, c); 1867 return; 1868 } 1869 /* check if the fixed size part of the packet is in buffer. */ 1870 if (have < 3) 1871 return; 1872 /* try to guess the protocol */ 1873 p = sshbuf_ptr(c->output); 1874 switch (p[0]) { 1875 case 0x04: 1876 /* switch input/output for reverse forwarding */ 1877 ret = channel_decode_socks4(c, c->output, c->input); 1878 break; 1879 case 0x05: 1880 ret = channel_decode_socks5(c, c->output, c->input); 1881 break; 1882 default: 1883 ret = -1; 1884 break; 1885 } 1886 if (ret < 0) { 1887 rdynamic_close(ssh, c); 1888 } else if (ret == 0) { 1889 debug2("channel %d: pre_rdynamic: need more", c->self); 1890 /* send socks request to peer */ 1891 len = sshbuf_len(c->input); 1892 if (len > 0 && len < c->remote_window) { 1893 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1894 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1895 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1896 (r = sshpkt_send(ssh)) != 0) { 1897 fatal_fr(r, "channel %i: rdynamic", c->self); 1898 } 1899 if ((r = sshbuf_consume(c->input, len)) != 0) 1900 fatal_fr(r, "channel %d: consume", c->self); 1901 c->remote_window -= len; 1902 } 1903 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1904 /* the connect failed */ 1905 rdynamic_close(ssh, c); 1906 } 1907 } 1908 1909 /* This is our fake X11 server socket. */ 1910 static void 1911 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1912 { 1913 Channel *nc; 1914 struct sockaddr_storage addr; 1915 int r, newsock, oerrno, remote_port; 1916 socklen_t addrlen; 1917 char buf[16384], *remote_ipaddr; 1918 1919 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1920 return; 1921 1922 debug("X11 connection requested."); 1923 addrlen = sizeof(addr); 1924 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1925 if (c->single_connection) { 1926 oerrno = errno; 1927 debug2("single_connection: closing X11 listener."); 1928 channel_close_fd(ssh, c, &c->sock); 1929 chan_mark_dead(ssh, c); 1930 errno = oerrno; 1931 } 1932 if (newsock == -1) { 1933 if (errno != EINTR && errno != EWOULDBLOCK && 1934 errno != ECONNABORTED) 1935 error("accept: %.100s", strerror(errno)); 1936 if (errno == EMFILE || errno == ENFILE) 1937 c->notbefore = monotime() + 1; 1938 return; 1939 } 1940 set_nodelay(newsock); 1941 remote_ipaddr = get_peer_ipaddr(newsock); 1942 remote_port = get_peer_port(newsock); 1943 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1944 remote_ipaddr, remote_port); 1945 1946 nc = channel_new(ssh, "x11-connection", 1947 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1948 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1949 open_preamble(ssh, __func__, nc, "x11"); 1950 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1951 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1952 fatal_fr(r, "channel %i: reply", c->self); 1953 } 1954 if ((r = sshpkt_send(ssh)) != 0) 1955 fatal_fr(r, "channel %i: send", c->self); 1956 free(remote_ipaddr); 1957 } 1958 1959 static void 1960 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1961 { 1962 char *local_ipaddr = get_local_ipaddr(c->sock); 1963 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1964 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1965 int remote_port = get_peer_port(c->sock); 1966 int r; 1967 1968 if (remote_port == -1) { 1969 /* Fake addr/port to appease peers that validate it (Tectia) */ 1970 free(remote_ipaddr); 1971 remote_ipaddr = xstrdup("127.0.0.1"); 1972 remote_port = 65535; 1973 } 1974 1975 free(c->remote_name); 1976 xasprintf(&c->remote_name, 1977 "%s: listening port %d for %.100s port %d, " 1978 "connect from %.200s port %d to %.100s port %d", 1979 rtype, c->listening_port, c->path, c->host_port, 1980 remote_ipaddr, remote_port, local_ipaddr, local_port); 1981 1982 open_preamble(ssh, __func__, c, rtype); 1983 if (strcmp(rtype, "direct-tcpip") == 0) { 1984 /* target host, port */ 1985 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1986 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1987 fatal_fr(r, "channel %i: reply", c->self); 1988 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1989 /* target path */ 1990 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1991 fatal_fr(r, "channel %i: reply", c->self); 1992 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1993 /* listen path */ 1994 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1995 fatal_fr(r, "channel %i: reply", c->self); 1996 } else { 1997 /* listen address, port */ 1998 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1999 (r = sshpkt_put_u32(ssh, local_port)) != 0) 2000 fatal_fr(r, "channel %i: reply", c->self); 2001 } 2002 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 2003 /* reserved for future owner/mode info */ 2004 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 2005 fatal_fr(r, "channel %i: reply", c->self); 2006 } else { 2007 /* originator host and port */ 2008 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 2009 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 2010 fatal_fr(r, "channel %i: reply", c->self); 2011 } 2012 if ((r = sshpkt_send(ssh)) != 0) 2013 fatal_fr(r, "channel %i: send", c->self); 2014 free(remote_ipaddr); 2015 free(local_ipaddr); 2016 } 2017 2018 void 2019 channel_set_x11_refuse_time(struct ssh *ssh, time_t refuse_time) 2020 { 2021 ssh->chanctxt->x11_refuse_time = refuse_time; 2022 } 2023 2024 /* 2025 * This socket is listening for connections to a forwarded TCP/IP port. 2026 */ 2027 static void 2028 channel_post_port_listener(struct ssh *ssh, Channel *c) 2029 { 2030 Channel *nc; 2031 struct sockaddr_storage addr; 2032 int newsock, nextstate; 2033 socklen_t addrlen; 2034 char *rtype; 2035 2036 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2037 return; 2038 2039 debug("Connection to port %d forwarding to %.100s port %d requested.", 2040 c->listening_port, c->path, c->host_port); 2041 2042 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 2043 nextstate = SSH_CHANNEL_OPENING; 2044 rtype = "forwarded-tcpip"; 2045 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 2046 nextstate = SSH_CHANNEL_OPENING; 2047 rtype = "forwarded-streamlocal@openssh.com"; 2048 } else if (c->host_port == PORT_STREAMLOCAL) { 2049 nextstate = SSH_CHANNEL_OPENING; 2050 rtype = "direct-streamlocal@openssh.com"; 2051 } else if (c->host_port == 0) { 2052 nextstate = SSH_CHANNEL_DYNAMIC; 2053 rtype = "dynamic-tcpip"; 2054 } else { 2055 nextstate = SSH_CHANNEL_OPENING; 2056 rtype = "direct-tcpip"; 2057 } 2058 2059 addrlen = sizeof(addr); 2060 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2061 if (newsock == -1) { 2062 if (errno != EINTR && errno != EWOULDBLOCK && 2063 errno != ECONNABORTED) 2064 error("accept: %.100s", strerror(errno)); 2065 if (errno == EMFILE || errno == ENFILE) 2066 c->notbefore = monotime() + 1; 2067 return; 2068 } 2069 if (c->host_port != PORT_STREAMLOCAL) 2070 set_nodelay(newsock); 2071 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 2072 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 2073 nc->listening_port = c->listening_port; 2074 nc->host_port = c->host_port; 2075 if (c->path != NULL) 2076 nc->path = xstrdup(c->path); 2077 2078 if (nextstate != SSH_CHANNEL_DYNAMIC) 2079 port_open_helper(ssh, nc, rtype); 2080 } 2081 2082 /* 2083 * This is the authentication agent socket listening for connections from 2084 * clients. 2085 */ 2086 static void 2087 channel_post_auth_listener(struct ssh *ssh, Channel *c) 2088 { 2089 Channel *nc; 2090 int r, newsock; 2091 struct sockaddr_storage addr; 2092 socklen_t addrlen; 2093 2094 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2095 return; 2096 2097 addrlen = sizeof(addr); 2098 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 2099 if (newsock == -1) { 2100 error("accept from auth socket: %.100s", strerror(errno)); 2101 if (errno == EMFILE || errno == ENFILE) 2102 c->notbefore = monotime() + 1; 2103 return; 2104 } 2105 nc = channel_new(ssh, "agent-connection", 2106 SSH_CHANNEL_OPENING, newsock, newsock, -1, 2107 c->local_window_max, c->local_maxpacket, 2108 0, "accepted auth socket", 1); 2109 open_preamble(ssh, __func__, nc, 2110 c->agent_new ? "agent-connect" : "auth-agent@openssh.com"); 2111 if ((r = sshpkt_send(ssh)) != 0) 2112 fatal_fr(r, "channel %i", c->self); 2113 } 2114 2115 static void 2116 channel_post_connecting(struct ssh *ssh, Channel *c) 2117 { 2118 int err = 0, sock, isopen, r; 2119 socklen_t sz = sizeof(err); 2120 2121 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 2122 return; 2123 if (!c->have_remote_id) 2124 fatal_f("channel %d: no remote id", c->self); 2125 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 2126 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 2127 2128 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 2129 err = errno; 2130 error("getsockopt SO_ERROR failed"); 2131 } 2132 2133 if (err == 0) { 2134 /* Non-blocking connection completed */ 2135 debug("channel %d: connected to %s port %d", 2136 c->self, c->connect_ctx.host, c->connect_ctx.port); 2137 channel_connect_ctx_free(&c->connect_ctx); 2138 c->type = SSH_CHANNEL_OPEN; 2139 channel_set_used_time(ssh, c); 2140 if (isopen) { 2141 /* no message necessary */ 2142 } else { 2143 if ((r = sshpkt_start(ssh, 2144 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 2145 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2146 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 2147 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 2148 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 2149 (r = sshpkt_send(ssh)) != 0) 2150 fatal_fr(r, "channel %i open confirm", c->self); 2151 } 2152 return; 2153 } 2154 if (err == EINTR || err == EAGAIN || err == EINPROGRESS) 2155 return; 2156 2157 /* Non-blocking connection failed */ 2158 debug("channel %d: connection failed: %s", c->self, strerror(err)); 2159 2160 /* Try next address, if any */ 2161 if ((sock = connect_next(&c->connect_ctx)) == -1) { 2162 /* Exhausted all addresses for this destination */ 2163 error("connect_to %.100s port %d: failed.", 2164 c->connect_ctx.host, c->connect_ctx.port); 2165 channel_connect_ctx_free(&c->connect_ctx); 2166 if (isopen) { 2167 rdynamic_close(ssh, c); 2168 } else { 2169 if ((r = sshpkt_start(ssh, 2170 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 2171 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2172 (r = sshpkt_put_u32(ssh, 2173 SSH2_OPEN_CONNECT_FAILED)) != 0 || 2174 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 2175 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2176 (r = sshpkt_send(ssh)) != 0) 2177 fatal_fr(r, "channel %i: failure", c->self); 2178 chan_mark_dead(ssh, c); 2179 } 2180 } 2181 2182 /* New non-blocking connection in progress */ 2183 close(c->sock); 2184 c->sock = c->rfd = c->wfd = sock; 2185 } 2186 2187 static int 2188 channel_handle_rfd(struct ssh *ssh, Channel *c) 2189 { 2190 char buf[CHAN_RBUF]; 2191 ssize_t len; 2192 int r, force; 2193 size_t nr = 0, have, avail, maxlen = CHANNEL_MAX_READ; 2194 int pty_zeroread = 0; 2195 2196 #ifdef PTY_ZEROREAD 2197 /* Bug on AIX: read(1) can return 0 for a non-closed fd */ 2198 pty_zeroread = c->isatty; 2199 #endif 2200 2201 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2202 2203 if (!force && (c->io_ready & SSH_CHAN_IO_RFD) == 0) 2204 return 1; 2205 if ((avail = sshbuf_avail(c->input)) == 0) 2206 return 1; /* Shouldn't happen */ 2207 2208 /* 2209 * For "simple" channels (i.e. not datagram or filtered), we can 2210 * read directly to the channel buffer. 2211 */ 2212 if (!pty_zeroread && c->input_filter == NULL && !c->datagram) { 2213 /* Only OPEN channels have valid rwin */ 2214 if (c->type == SSH_CHANNEL_OPEN) { 2215 if ((have = sshbuf_len(c->input)) >= c->remote_window) 2216 return 1; /* shouldn't happen */ 2217 if (maxlen > c->remote_window - have) 2218 maxlen = c->remote_window - have; 2219 } 2220 if (maxlen > avail) 2221 maxlen = avail; 2222 if ((r = sshbuf_read(c->rfd, c->input, maxlen, &nr)) != 0) { 2223 if (errno == EINTR || (!force && 2224 (errno == EAGAIN || errno == EWOULDBLOCK))) 2225 return 1; 2226 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 2227 c->self, c->rfd, maxlen, ssh_err(r)); 2228 goto rfail; 2229 } 2230 if (nr != 0) 2231 channel_set_used_time(ssh, c); 2232 return 1; 2233 } 2234 2235 errno = 0; 2236 len = read(c->rfd, buf, sizeof(buf)); 2237 /* fixup AIX zero-length read with errno set to look more like errors */ 2238 if (pty_zeroread && len == 0 && errno != 0) 2239 len = -1; 2240 if (len == -1 && (errno == EINTR || 2241 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 2242 return 1; 2243 if (len < 0 || (!pty_zeroread && len == 0)) { 2244 debug2("channel %d: read<=0 rfd %d len %zd: %s", 2245 c->self, c->rfd, len, 2246 len == 0 ? "closed" : strerror(errno)); 2247 rfail: 2248 if (c->type != SSH_CHANNEL_OPEN) { 2249 debug2("channel %d: not open", c->self); 2250 chan_mark_dead(ssh, c); 2251 return -1; 2252 } else { 2253 chan_read_failed(ssh, c); 2254 } 2255 return -1; 2256 } 2257 channel_set_used_time(ssh, c); 2258 if (c->input_filter != NULL) { 2259 if (c->input_filter(ssh, c, buf, len) == -1) { 2260 debug2("channel %d: filter stops", c->self); 2261 chan_read_failed(ssh, c); 2262 } 2263 } else if (c->datagram) { 2264 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2265 fatal_fr(r, "channel %i: put datagram", c->self); 2266 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2267 fatal_fr(r, "channel %i: put data", c->self); 2268 2269 return 1; 2270 } 2271 2272 static int 2273 channel_handle_wfd(struct ssh *ssh, Channel *c) 2274 { 2275 struct termios tio; 2276 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2277 size_t dlen, olen = 0; 2278 int r, len; 2279 2280 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2281 return 1; 2282 if (sshbuf_len(c->output) == 0) 2283 return 1; 2284 2285 /* Send buffered output data to the socket. */ 2286 olen = sshbuf_len(c->output); 2287 if (c->output_filter != NULL) { 2288 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2289 debug2("channel %d: filter stops", c->self); 2290 if (c->type != SSH_CHANNEL_OPEN) 2291 chan_mark_dead(ssh, c); 2292 else 2293 chan_write_failed(ssh, c); 2294 return -1; 2295 } 2296 } else if (c->datagram) { 2297 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2298 fatal_fr(r, "channel %i: get datagram", c->self); 2299 buf = data; 2300 } else { 2301 buf = data = sshbuf_mutable_ptr(c->output); 2302 dlen = sshbuf_len(c->output); 2303 } 2304 2305 if (c->datagram) { 2306 /* ignore truncated writes, datagrams might get lost */ 2307 len = write(c->wfd, buf, dlen); 2308 free(data); 2309 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2310 errno == EWOULDBLOCK)) 2311 return 1; 2312 if (len <= 0) 2313 goto write_fail; 2314 goto out; 2315 } 2316 2317 #ifdef _AIX 2318 /* XXX: Later AIX versions can't push as much data to tty */ 2319 if (c->wfd_isatty) 2320 dlen = MINIMUM(dlen, 8*1024); 2321 #endif 2322 2323 len = write(c->wfd, buf, dlen); 2324 if (len == -1 && 2325 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 2326 return 1; 2327 if (len <= 0) { 2328 write_fail: 2329 if (c->type != SSH_CHANNEL_OPEN) { 2330 debug2("channel %d: not open", c->self); 2331 chan_mark_dead(ssh, c); 2332 return -1; 2333 } else { 2334 chan_write_failed(ssh, c); 2335 } 2336 return -1; 2337 } 2338 channel_set_used_time(ssh, c); 2339 #ifndef BROKEN_TCGETATTR_ICANON 2340 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2341 if (tcgetattr(c->wfd, &tio) == 0 && 2342 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2343 /* 2344 * Simulate echo to reduce the impact of 2345 * traffic analysis. We need to match the 2346 * size of a SSH2_MSG_CHANNEL_DATA message 2347 * (4 byte channel id + buf) 2348 */ 2349 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2350 (r = sshpkt_send(ssh)) != 0) 2351 fatal_fr(r, "channel %i: ignore", c->self); 2352 } 2353 } 2354 #endif /* BROKEN_TCGETATTR_ICANON */ 2355 if ((r = sshbuf_consume(c->output, len)) != 0) 2356 fatal_fr(r, "channel %i: consume", c->self); 2357 out: 2358 c->local_consumed += olen - sshbuf_len(c->output); 2359 2360 return 1; 2361 } 2362 2363 static int 2364 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2365 { 2366 int r; 2367 ssize_t len; 2368 2369 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2370 return 1; 2371 if (sshbuf_len(c->extended) == 0) 2372 return 1; 2373 2374 len = write(c->efd, sshbuf_ptr(c->extended), 2375 sshbuf_len(c->extended)); 2376 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2377 if (len == -1 && (errno == EINTR || errno == EAGAIN || 2378 errno == EWOULDBLOCK)) 2379 return 1; 2380 if (len <= 0) { 2381 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2382 channel_close_fd(ssh, c, &c->efd); 2383 } else { 2384 if ((r = sshbuf_consume(c->extended, len)) != 0) 2385 fatal_fr(r, "channel %i: consume", c->self); 2386 c->local_consumed += len; 2387 channel_set_used_time(ssh, c); 2388 } 2389 return 1; 2390 } 2391 2392 static int 2393 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2394 { 2395 char buf[CHAN_RBUF]; 2396 ssize_t len; 2397 int r, force; 2398 2399 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 2400 2401 if (!force && (c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2402 return 1; 2403 2404 len = read(c->efd, buf, sizeof(buf)); 2405 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2406 if (len == -1 && (errno == EINTR || ((errno == EAGAIN || 2407 errno == EWOULDBLOCK) && !force))) 2408 return 1; 2409 if (len <= 0) { 2410 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2411 channel_close_fd(ssh, c, &c->efd); 2412 return 1; 2413 } 2414 channel_set_used_time(ssh, c); 2415 if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2416 debug3("channel %d: discard efd", c->self); 2417 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2418 fatal_fr(r, "channel %i: append", c->self); 2419 return 1; 2420 } 2421 2422 static int 2423 channel_handle_efd(struct ssh *ssh, Channel *c) 2424 { 2425 if (c->efd == -1) 2426 return 1; 2427 2428 /** XXX handle drain efd, too */ 2429 2430 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2431 return channel_handle_efd_write(ssh, c); 2432 else if (c->extended_usage == CHAN_EXTENDED_READ || 2433 c->extended_usage == CHAN_EXTENDED_IGNORE) 2434 return channel_handle_efd_read(ssh, c); 2435 2436 return 1; 2437 } 2438 2439 static int 2440 channel_check_window(struct ssh *ssh, Channel *c) 2441 { 2442 int r; 2443 2444 if (c->type == SSH_CHANNEL_OPEN && 2445 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2446 ((c->local_window_max - c->local_window > 2447 c->local_maxpacket*3) || 2448 c->local_window < c->local_window_max/2) && 2449 c->local_consumed > 0) { 2450 if (!c->have_remote_id) 2451 fatal_f("channel %d: no remote id", c->self); 2452 if ((r = sshpkt_start(ssh, 2453 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2454 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2455 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2456 (r = sshpkt_send(ssh)) != 0) { 2457 fatal_fr(r, "channel %i", c->self); 2458 } 2459 debug2("channel %d: window %d sent adjust %d", c->self, 2460 c->local_window, c->local_consumed); 2461 c->local_window += c->local_consumed; 2462 c->local_consumed = 0; 2463 } 2464 return 1; 2465 } 2466 2467 static void 2468 channel_post_open(struct ssh *ssh, Channel *c) 2469 { 2470 channel_handle_rfd(ssh, c); 2471 channel_handle_wfd(ssh, c); 2472 channel_handle_efd(ssh, c); 2473 channel_check_window(ssh, c); 2474 } 2475 2476 static u_int 2477 read_mux(struct ssh *ssh, Channel *c, u_int need) 2478 { 2479 char buf[CHAN_RBUF]; 2480 ssize_t len; 2481 u_int rlen; 2482 int r; 2483 2484 if (sshbuf_len(c->input) < need) { 2485 rlen = need - sshbuf_len(c->input); 2486 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2487 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2488 return sshbuf_len(c->input); 2489 if (len <= 0) { 2490 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2491 c->self, c->rfd, len); 2492 chan_read_failed(ssh, c); 2493 return 0; 2494 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2495 fatal_fr(r, "channel %i: append", c->self); 2496 } 2497 return sshbuf_len(c->input); 2498 } 2499 2500 static void 2501 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2502 { 2503 u_int need; 2504 2505 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2506 return; 2507 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2508 return; 2509 if (c->mux_pause) 2510 return; 2511 2512 /* 2513 * Don't not read past the precise end of packets to 2514 * avoid disrupting fd passing. 2515 */ 2516 if (read_mux(ssh, c, 4) < 4) /* read header */ 2517 return; 2518 /* XXX sshbuf_peek_u32 */ 2519 need = PEEK_U32(sshbuf_ptr(c->input)); 2520 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2521 if (need > CHANNEL_MUX_MAX_PACKET) { 2522 debug2("channel %d: packet too big %u > %u", 2523 c->self, CHANNEL_MUX_MAX_PACKET, need); 2524 chan_rcvd_oclose(ssh, c); 2525 return; 2526 } 2527 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2528 return; 2529 if (c->mux_rcb(ssh, c) != 0) { 2530 debug("channel %d: mux_rcb failed", c->self); 2531 chan_mark_dead(ssh, c); 2532 return; 2533 } 2534 } 2535 2536 static void 2537 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2538 { 2539 ssize_t len; 2540 int r; 2541 2542 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2543 return; 2544 if (sshbuf_len(c->output) == 0) 2545 return; 2546 2547 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2548 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2549 return; 2550 if (len <= 0) { 2551 chan_mark_dead(ssh, c); 2552 return; 2553 } 2554 if ((r = sshbuf_consume(c->output, len)) != 0) 2555 fatal_fr(r, "channel %i: consume", c->self); 2556 } 2557 2558 static void 2559 channel_post_mux_client(struct ssh *ssh, Channel *c) 2560 { 2561 channel_post_mux_client_read(ssh, c); 2562 channel_post_mux_client_write(ssh, c); 2563 } 2564 2565 static void 2566 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2567 { 2568 Channel *nc; 2569 struct sockaddr_storage addr; 2570 socklen_t addrlen; 2571 int newsock; 2572 uid_t euid; 2573 gid_t egid; 2574 2575 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2576 return; 2577 2578 debug("multiplexing control connection"); 2579 2580 /* 2581 * Accept connection on control socket 2582 */ 2583 memset(&addr, 0, sizeof(addr)); 2584 addrlen = sizeof(addr); 2585 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2586 &addrlen)) == -1) { 2587 error_f("accept: %s", strerror(errno)); 2588 if (errno == EMFILE || errno == ENFILE) 2589 c->notbefore = monotime() + 1; 2590 return; 2591 } 2592 2593 if (getpeereid(newsock, &euid, &egid) == -1) { 2594 error_f("getpeereid failed: %s", strerror(errno)); 2595 close(newsock); 2596 return; 2597 } 2598 if ((euid != 0) && (getuid() != euid)) { 2599 error("multiplex uid mismatch: peer euid %u != uid %u", 2600 (u_int)euid, (u_int)getuid()); 2601 close(newsock); 2602 return; 2603 } 2604 nc = channel_new(ssh, "mux-control", SSH_CHANNEL_MUX_CLIENT, 2605 newsock, newsock, -1, c->local_window_max, 2606 c->local_maxpacket, 0, "mux-control", 1); 2607 nc->mux_rcb = c->mux_rcb; 2608 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2609 /* establish state */ 2610 nc->mux_rcb(ssh, nc); 2611 /* mux state transitions must not elicit protocol messages */ 2612 nc->flags |= CHAN_LOCAL; 2613 } 2614 2615 static void 2616 channel_handler_init(struct ssh_channels *sc) 2617 { 2618 chan_fn **pre, **post; 2619 2620 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2621 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2622 fatal_f("allocation failed"); 2623 2624 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2625 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2626 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2627 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2628 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2629 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2630 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2631 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2632 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2633 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2634 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2635 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2636 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2637 2638 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2639 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2640 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2641 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2642 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2643 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2644 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2645 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2646 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2647 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2648 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2649 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2650 2651 sc->channel_pre = pre; 2652 sc->channel_post = post; 2653 } 2654 2655 /* gc dead channels */ 2656 static void 2657 channel_garbage_collect(struct ssh *ssh, Channel *c) 2658 { 2659 if (c == NULL) 2660 return; 2661 if (c->detach_user != NULL) { 2662 if (!chan_is_dead(ssh, c, c->detach_close)) 2663 return; 2664 2665 debug2("channel %d: gc: notify user", c->self); 2666 c->detach_user(ssh, c->self, 0, NULL); 2667 /* if we still have a callback */ 2668 if (c->detach_user != NULL) 2669 return; 2670 debug2("channel %d: gc: user detached", c->self); 2671 } 2672 if (!chan_is_dead(ssh, c, 1)) 2673 return; 2674 debug2("channel %d: garbage collecting", c->self); 2675 channel_free(ssh, c); 2676 } 2677 2678 enum channel_table { CHAN_PRE, CHAN_POST }; 2679 2680 static void 2681 channel_handler(struct ssh *ssh, int table, struct timespec *timeout) 2682 { 2683 struct ssh_channels *sc = ssh->chanctxt; 2684 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2685 u_int i, oalloc; 2686 Channel *c; 2687 time_t now; 2688 2689 now = monotime(); 2690 for (sc->nbulk = i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2691 c = sc->channels[i]; 2692 if (c == NULL) 2693 continue; 2694 /* Count open channels in bulk state */ 2695 if (c->type == SSH_CHANNEL_OPEN && c->bulk) 2696 sc->nbulk++; 2697 /* Try to keep IO going while rekeying */ 2698 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2699 continue; 2700 if (c->delayed) { 2701 if (table == CHAN_PRE) 2702 c->delayed = 0; 2703 else 2704 continue; 2705 } 2706 if (ftab[c->type] != NULL) { 2707 if (table == CHAN_PRE && c->type == SSH_CHANNEL_OPEN && 2708 channel_get_expiry(ssh, c) != 0 && 2709 now >= channel_get_expiry(ssh, c)) { 2710 /* channel closed for inactivity */ 2711 verbose("channel %d: closing after %u seconds " 2712 "of inactivity", c->self, 2713 c->inactive_deadline); 2714 channel_force_close(ssh, c, 1); 2715 } else if (c->notbefore <= now) { 2716 /* Run handlers that are not paused. */ 2717 (*ftab[c->type])(ssh, c); 2718 /* inactivity timeouts must interrupt poll() */ 2719 if (timeout != NULL && 2720 c->type == SSH_CHANNEL_OPEN && 2721 channel_get_expiry(ssh, c) != 0) { 2722 ptimeout_deadline_monotime(timeout, 2723 channel_get_expiry(ssh, c)); 2724 } 2725 } else if (timeout != NULL) { 2726 /* 2727 * Arrange for poll() wakeup when channel pause 2728 * timer expires. 2729 */ 2730 ptimeout_deadline_monotime(timeout, 2731 c->notbefore); 2732 } 2733 } 2734 channel_garbage_collect(ssh, c); 2735 } 2736 } 2737 2738 /* 2739 * Create sockets before preparing IO. 2740 * This is necessary for things that need to happen after reading 2741 * the network-input but need to be completed before IO event setup, e.g. 2742 * because they may create new channels. 2743 */ 2744 static void 2745 channel_before_prepare_io(struct ssh *ssh) 2746 { 2747 struct ssh_channels *sc = ssh->chanctxt; 2748 Channel *c; 2749 u_int i, oalloc; 2750 2751 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2752 c = sc->channels[i]; 2753 if (c == NULL) 2754 continue; 2755 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2756 channel_before_prepare_io_rdynamic(ssh, c); 2757 } 2758 } 2759 2760 static void 2761 dump_channel_poll(const char *func, const char *what, Channel *c, 2762 u_int pollfd_offset, struct pollfd *pfd) 2763 { 2764 #ifdef DEBUG_CHANNEL_POLL 2765 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2766 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2767 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2768 c->rfd, c->wfd, c->efd, c->sock, 2769 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2770 c->io_want, c->io_ready, 2771 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2772 #endif 2773 } 2774 2775 /* Prepare pollfd entries for a single channel */ 2776 static void 2777 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2778 struct pollfd *pfd, u_int npfd) 2779 { 2780 u_int ev, p = *next_pollfd; 2781 2782 if (c == NULL) 2783 return; 2784 if (p + 4 > npfd) { 2785 /* Shouldn't happen */ 2786 fatal_f("channel %d: bad pfd offset %u (max %u)", 2787 c->self, p, npfd); 2788 } 2789 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2790 /* 2791 * prepare c->rfd 2792 * 2793 * This is a special case, since c->rfd might be the same as 2794 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2795 * IO too. 2796 */ 2797 if (c->rfd != -1) { 2798 ev = 0; 2799 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2800 ev |= POLLIN; 2801 /* rfd == wfd */ 2802 if (c->wfd == c->rfd) { 2803 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2804 ev |= POLLOUT; 2805 } 2806 /* rfd == efd */ 2807 if (c->efd == c->rfd) { 2808 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2809 ev |= POLLIN; 2810 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2811 ev |= POLLOUT; 2812 } 2813 /* rfd == sock */ 2814 if (c->sock == c->rfd) { 2815 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2816 ev |= POLLIN; 2817 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2818 ev |= POLLOUT; 2819 } 2820 /* Pack a pfd entry if any event armed for this fd */ 2821 if (ev != 0) { 2822 c->pfds[0] = p; 2823 pfd[p].fd = c->rfd; 2824 pfd[p].events = ev; 2825 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2826 p++; 2827 } 2828 } 2829 /* prepare c->wfd if wanting IO and not already handled above */ 2830 if (c->wfd != -1 && c->rfd != c->wfd) { 2831 ev = 0; 2832 if ((c->io_want & SSH_CHAN_IO_WFD)) 2833 ev |= POLLOUT; 2834 /* Pack a pfd entry if any event armed for this fd */ 2835 if (ev != 0) { 2836 c->pfds[1] = p; 2837 pfd[p].fd = c->wfd; 2838 pfd[p].events = ev; 2839 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2840 p++; 2841 } 2842 } 2843 /* prepare c->efd if wanting IO and not already handled above */ 2844 if (c->efd != -1 && c->rfd != c->efd) { 2845 ev = 0; 2846 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2847 ev |= POLLIN; 2848 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2849 ev |= POLLOUT; 2850 /* Pack a pfd entry if any event armed for this fd */ 2851 if (ev != 0) { 2852 c->pfds[2] = p; 2853 pfd[p].fd = c->efd; 2854 pfd[p].events = ev; 2855 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2856 p++; 2857 } 2858 } 2859 /* prepare c->sock if wanting IO and not already handled above */ 2860 if (c->sock != -1 && c->rfd != c->sock) { 2861 ev = 0; 2862 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2863 ev |= POLLIN; 2864 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2865 ev |= POLLOUT; 2866 /* Pack a pfd entry if any event armed for this fd */ 2867 if (ev != 0) { 2868 c->pfds[3] = p; 2869 pfd[p].fd = c->sock; 2870 pfd[p].events = ev; 2871 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2872 p++; 2873 } 2874 } 2875 *next_pollfd = p; 2876 } 2877 2878 /* * Allocate/prepare poll structure */ 2879 void 2880 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2881 u_int *npfd_activep, u_int npfd_reserved, struct timespec *timeout) 2882 { 2883 struct ssh_channels *sc = ssh->chanctxt; 2884 u_int i, oalloc, p, npfd = npfd_reserved; 2885 2886 channel_before_prepare_io(ssh); /* might create a new channel */ 2887 /* clear out I/O flags from last poll */ 2888 for (i = 0; i < sc->channels_alloc; i++) { 2889 if (sc->channels[i] == NULL) 2890 continue; 2891 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2892 } 2893 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2894 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2895 fatal_f("too many channels"); /* shouldn't happen */ 2896 npfd += sc->channels_alloc * 4; 2897 if (npfd > *npfd_allocp) { 2898 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2899 npfd, sizeof(**pfdp)); 2900 *npfd_allocp = npfd; 2901 } 2902 *npfd_activep = npfd_reserved; 2903 oalloc = sc->channels_alloc; 2904 2905 channel_handler(ssh, CHAN_PRE, timeout); 2906 2907 if (oalloc != sc->channels_alloc) { 2908 /* shouldn't happen */ 2909 fatal_f("channels_alloc changed during CHAN_PRE " 2910 "(was %u, now %u)", oalloc, sc->channels_alloc); 2911 } 2912 2913 /* Prepare pollfd */ 2914 p = npfd_reserved; 2915 for (i = 0; i < sc->channels_alloc; i++) 2916 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2917 *npfd_activep = p; 2918 } 2919 2920 static void 2921 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2922 const char *what, u_int revents_mask, u_int ready) 2923 { 2924 struct pollfd *pfd = &pfds[p]; 2925 2926 if (fd == -1) 2927 return; 2928 if (p == -1 || (u_int)p >= npfd) 2929 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2930 dump_channel_poll(__func__, what, c, p, pfd); 2931 if (pfd->fd != fd) { 2932 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2933 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2934 c->rfd, c->wfd, c->efd, c->sock); 2935 } 2936 if ((pfd->revents & POLLNVAL) != 0) { 2937 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2938 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2939 } 2940 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2941 c->io_ready |= ready & c->io_want; 2942 } 2943 2944 /* 2945 * After poll, perform any appropriate operations for channels which have 2946 * events pending. 2947 */ 2948 void 2949 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2950 { 2951 struct ssh_channels *sc = ssh->chanctxt; 2952 u_int i; 2953 int p; 2954 Channel *c; 2955 2956 #ifdef DEBUG_CHANNEL_POLL 2957 for (p = 0; p < (int)npfd; p++) { 2958 if (pfd[p].revents == 0) 2959 continue; 2960 debug_f("pfd[%u].fd %d rev 0x%04x", 2961 p, pfd[p].fd, pfd[p].revents); 2962 } 2963 #endif 2964 2965 /* Convert pollfd into c->io_ready */ 2966 for (i = 0; i < sc->channels_alloc; i++) { 2967 c = sc->channels[i]; 2968 if (c == NULL) 2969 continue; 2970 /* if rfd is shared with efd/sock then wfd should be too */ 2971 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2972 (c->rfd == c->efd || c->rfd == c->sock)) { 2973 /* Shouldn't happen */ 2974 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2975 c->self, c->rfd, c->wfd, c->efd, c->sock); 2976 } 2977 c->io_ready = 0; 2978 /* rfd, potentially shared with wfd, efd and sock */ 2979 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2980 fd_ready(c, p, pfd, npfd, c->rfd, 2981 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2982 if (c->rfd == c->wfd) { 2983 fd_ready(c, p, pfd, npfd, c->wfd, 2984 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2985 } 2986 if (c->rfd == c->efd) { 2987 fd_ready(c, p, pfd, npfd, c->efd, 2988 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2989 fd_ready(c, p, pfd, npfd, c->efd, 2990 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2991 } 2992 if (c->rfd == c->sock) { 2993 fd_ready(c, p, pfd, npfd, c->sock, 2994 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2995 fd_ready(c, p, pfd, npfd, c->sock, 2996 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2997 } 2998 dump_channel_poll(__func__, "rfd", c, p, pfd); 2999 } 3000 /* wfd */ 3001 if (c->wfd != -1 && c->wfd != c->rfd && 3002 (p = c->pfds[1]) != -1) { 3003 fd_ready(c, p, pfd, npfd, c->wfd, 3004 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 3005 dump_channel_poll(__func__, "wfd", c, p, pfd); 3006 } 3007 /* efd */ 3008 if (c->efd != -1 && c->efd != c->rfd && 3009 (p = c->pfds[2]) != -1) { 3010 fd_ready(c, p, pfd, npfd, c->efd, 3011 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 3012 fd_ready(c, p, pfd, npfd, c->efd, 3013 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 3014 dump_channel_poll(__func__, "efd", c, p, pfd); 3015 } 3016 /* sock */ 3017 if (c->sock != -1 && c->sock != c->rfd && 3018 (p = c->pfds[3]) != -1) { 3019 fd_ready(c, p, pfd, npfd, c->sock, 3020 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 3021 fd_ready(c, p, pfd, npfd, c->sock, 3022 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 3023 dump_channel_poll(__func__, "sock", c, p, pfd); 3024 } 3025 } 3026 channel_handler(ssh, CHAN_POST, NULL); 3027 } 3028 3029 /* 3030 * Enqueue data for channels with open or draining c->input. 3031 * Returns non-zero if a packet was enqueued. 3032 */ 3033 static int 3034 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 3035 { 3036 size_t len, plen; 3037 const u_char *pkt; 3038 int r; 3039 3040 if ((len = sshbuf_len(c->input)) == 0) { 3041 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 3042 /* 3043 * input-buffer is empty and read-socket shutdown: 3044 * tell peer, that we will not send more data: 3045 * send IEOF. 3046 * hack for extended data: delay EOF if EFD still 3047 * in use. 3048 */ 3049 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 3050 debug2("channel %d: " 3051 "ibuf_empty delayed efd %d/(%zu)", 3052 c->self, c->efd, sshbuf_len(c->extended)); 3053 else 3054 chan_ibuf_empty(ssh, c); 3055 } 3056 return 0; 3057 } 3058 3059 if (!c->have_remote_id) 3060 fatal_f("channel %d: no remote id", c->self); 3061 3062 if (c->datagram) { 3063 /* Check datagram will fit; drop if not */ 3064 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 3065 fatal_fr(r, "channel %i: get datagram", c->self); 3066 /* 3067 * XXX this does tail-drop on the datagram queue which is 3068 * usually suboptimal compared to head-drop. Better to have 3069 * backpressure at read time? (i.e. read + discard) 3070 */ 3071 if (plen > c->remote_window || plen > c->remote_maxpacket) { 3072 debug("channel %d: datagram too big", c->self); 3073 return 0; 3074 } 3075 /* Enqueue it */ 3076 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 3077 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3078 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 3079 (r = sshpkt_send(ssh)) != 0) 3080 fatal_fr(r, "channel %i: send datagram", c->self); 3081 c->remote_window -= plen; 3082 return 1; 3083 } 3084 3085 /* Enqueue packet for buffered data. */ 3086 if (len > c->remote_window) 3087 len = c->remote_window; 3088 if (len > c->remote_maxpacket) 3089 len = c->remote_maxpacket; 3090 if (len == 0) 3091 return 0; 3092 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 3093 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3094 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 3095 (r = sshpkt_send(ssh)) != 0) 3096 fatal_fr(r, "channel %i: send data", c->self); 3097 if ((r = sshbuf_consume(c->input, len)) != 0) 3098 fatal_fr(r, "channel %i: consume", c->self); 3099 c->remote_window -= len; 3100 return 1; 3101 } 3102 3103 /* 3104 * Enqueue data for channels with open c->extended in read mode. 3105 * Returns non-zero if a packet was enqueued. 3106 */ 3107 static int 3108 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 3109 { 3110 size_t len; 3111 int r; 3112 3113 if ((len = sshbuf_len(c->extended)) == 0) 3114 return 0; 3115 3116 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 3117 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 3118 if (len > c->remote_window) 3119 len = c->remote_window; 3120 if (len > c->remote_maxpacket) 3121 len = c->remote_maxpacket; 3122 if (len == 0) 3123 return 0; 3124 if (!c->have_remote_id) 3125 fatal_f("channel %d: no remote id", c->self); 3126 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 3127 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 3128 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 3129 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 3130 (r = sshpkt_send(ssh)) != 0) 3131 fatal_fr(r, "channel %i: data", c->self); 3132 if ((r = sshbuf_consume(c->extended, len)) != 0) 3133 fatal_fr(r, "channel %i: consume", c->self); 3134 c->remote_window -= len; 3135 debug2("channel %d: sent ext data %zu", c->self, len); 3136 return 1; 3137 } 3138 3139 /* 3140 * If there is data to send to the connection, enqueue some of it now. 3141 * Returns non-zero if data was enqueued. 3142 */ 3143 int 3144 channel_output_poll(struct ssh *ssh) 3145 { 3146 struct ssh_channels *sc = ssh->chanctxt; 3147 Channel *c; 3148 u_int i; 3149 int ret = 0; 3150 3151 for (i = 0; i < sc->channels_alloc; i++) { 3152 c = sc->channels[i]; 3153 if (c == NULL) 3154 continue; 3155 3156 /* 3157 * We are only interested in channels that can have buffered 3158 * incoming data. 3159 */ 3160 if (c->type != SSH_CHANNEL_OPEN) 3161 continue; 3162 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 3163 /* XXX is this true? */ 3164 debug3("channel %d: will not send data after close", 3165 c->self); 3166 continue; 3167 } 3168 3169 /* Get the amount of buffered data for this channel. */ 3170 if (c->istate == CHAN_INPUT_OPEN || 3171 c->istate == CHAN_INPUT_WAIT_DRAIN) 3172 ret |= channel_output_poll_input_open(ssh, c); 3173 /* Send extended data, i.e. stderr */ 3174 if (!(c->flags & CHAN_EOF_SENT) && 3175 c->extended_usage == CHAN_EXTENDED_READ) 3176 ret |= channel_output_poll_extended_read(ssh, c); 3177 } 3178 return ret; 3179 } 3180 3181 /* -- mux proxy support */ 3182 3183 /* 3184 * When multiplexing channel messages for mux clients we have to deal 3185 * with downstream messages from the mux client and upstream messages 3186 * from the ssh server: 3187 * 1) Handling downstream messages is straightforward and happens 3188 * in channel_proxy_downstream(): 3189 * - We forward all messages (mostly) unmodified to the server. 3190 * - However, in order to route messages from upstream to the correct 3191 * downstream client, we have to replace the channel IDs used by the 3192 * mux clients with a unique channel ID because the mux clients might 3193 * use conflicting channel IDs. 3194 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 3195 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 3196 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 3197 * with the newly allocated channel ID. 3198 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 3199 * channels and processed by channel_proxy_upstream(). The local channel ID 3200 * is then translated back to the original mux client ID. 3201 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 3202 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 3203 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 3204 * downstream mux client are removed. 3205 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 3206 * requires more work, because they are not addressed to a specific 3207 * channel. E.g. client_request_forwarded_tcpip() needs to figure 3208 * out whether the request is addressed to the local client or a 3209 * specific downstream client based on the listen-address/port. 3210 * 6) Agent and X11-Forwarding have a similar problem and are currently 3211 * not supported as the matching session/channel cannot be identified 3212 * easily. 3213 */ 3214 3215 /* 3216 * receive packets from downstream mux clients: 3217 * channel callback fired on read from mux client, creates 3218 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 3219 * on channel creation. 3220 */ 3221 int 3222 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 3223 { 3224 Channel *c = NULL; 3225 struct sshbuf *original = NULL, *modified = NULL; 3226 const u_char *cp; 3227 char *ctype = NULL, *listen_host = NULL; 3228 u_char type; 3229 size_t have; 3230 int ret = -1, r; 3231 u_int id, remote_id, listen_port; 3232 3233 /* sshbuf_dump(downstream->input, stderr); */ 3234 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 3235 != 0) { 3236 error_fr(r, "parse"); 3237 return -1; 3238 } 3239 if (have < 2) { 3240 error_f("short message"); 3241 return -1; 3242 } 3243 type = cp[1]; 3244 /* skip padlen + type */ 3245 cp += 2; 3246 have -= 2; 3247 if (ssh_packet_log_type(type)) 3248 debug3_f("channel %u: down->up: type %u", 3249 downstream->self, type); 3250 3251 switch (type) { 3252 case SSH2_MSG_CHANNEL_OPEN: 3253 if ((original = sshbuf_from(cp, have)) == NULL || 3254 (modified = sshbuf_new()) == NULL) { 3255 error_f("alloc"); 3256 goto out; 3257 } 3258 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 3259 (r = sshbuf_get_u32(original, &id)) != 0) { 3260 error_fr(r, "parse"); 3261 goto out; 3262 } 3263 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3264 -1, -1, -1, 0, 0, 0, ctype, 1); 3265 c->mux_ctx = downstream; /* point to mux client */ 3266 c->mux_downstream_id = id; /* original downstream id */ 3267 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 3268 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3269 (r = sshbuf_putb(modified, original)) != 0) { 3270 error_fr(r, "compose"); 3271 channel_free(ssh, c); 3272 goto out; 3273 } 3274 break; 3275 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3276 /* 3277 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 3278 * need to parse 'remote_id' instead of 'ctype'. 3279 */ 3280 if ((original = sshbuf_from(cp, have)) == NULL || 3281 (modified = sshbuf_new()) == NULL) { 3282 error_f("alloc"); 3283 goto out; 3284 } 3285 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3286 (r = sshbuf_get_u32(original, &id)) != 0) { 3287 error_fr(r, "parse"); 3288 goto out; 3289 } 3290 c = channel_new(ssh, "mux-proxy", SSH_CHANNEL_MUX_PROXY, 3291 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3292 c->mux_ctx = downstream; /* point to mux client */ 3293 c->mux_downstream_id = id; 3294 c->remote_id = remote_id; 3295 c->have_remote_id = 1; 3296 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3297 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3298 (r = sshbuf_putb(modified, original)) != 0) { 3299 error_fr(r, "compose"); 3300 channel_free(ssh, c); 3301 goto out; 3302 } 3303 break; 3304 case SSH2_MSG_GLOBAL_REQUEST: 3305 if ((original = sshbuf_from(cp, have)) == NULL) { 3306 error_f("alloc"); 3307 goto out; 3308 } 3309 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3310 error_fr(r, "parse"); 3311 goto out; 3312 } 3313 if (strcmp(ctype, "tcpip-forward") != 0) { 3314 error_f("unsupported request %s", ctype); 3315 goto out; 3316 } 3317 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3318 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3319 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3320 error_fr(r, "parse"); 3321 goto out; 3322 } 3323 if (listen_port > 65535) { 3324 error_f("tcpip-forward for %s: bad port %u", 3325 listen_host, listen_port); 3326 goto out; 3327 } 3328 /* Record that connection to this host/port is permitted. */ 3329 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", 3330 -1, listen_host, NULL, (int)listen_port, downstream); 3331 break; 3332 case SSH2_MSG_CHANNEL_CLOSE: 3333 if (have < 4) 3334 break; 3335 remote_id = PEEK_U32(cp); 3336 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3337 if (c->flags & CHAN_CLOSE_RCVD) 3338 channel_free(ssh, c); 3339 else 3340 c->flags |= CHAN_CLOSE_SENT; 3341 } 3342 break; 3343 } 3344 if (modified) { 3345 if ((r = sshpkt_start(ssh, type)) != 0 || 3346 (r = sshpkt_putb(ssh, modified)) != 0 || 3347 (r = sshpkt_send(ssh)) != 0) { 3348 error_fr(r, "send"); 3349 goto out; 3350 } 3351 } else { 3352 if ((r = sshpkt_start(ssh, type)) != 0 || 3353 (r = sshpkt_put(ssh, cp, have)) != 0 || 3354 (r = sshpkt_send(ssh)) != 0) { 3355 error_fr(r, "send"); 3356 goto out; 3357 } 3358 } 3359 ret = 0; 3360 out: 3361 free(ctype); 3362 free(listen_host); 3363 sshbuf_free(original); 3364 sshbuf_free(modified); 3365 return ret; 3366 } 3367 3368 /* 3369 * receive packets from upstream server and de-multiplex packets 3370 * to correct downstream: 3371 * implemented as a helper for channel input handlers, 3372 * replaces local (proxy) channel ID with downstream channel ID. 3373 */ 3374 int 3375 channel_proxy_upstream(Channel *c, int type, uint32_t seq, struct ssh *ssh) 3376 { 3377 struct sshbuf *b = NULL; 3378 Channel *downstream; 3379 const u_char *cp = NULL; 3380 size_t len; 3381 int r; 3382 3383 /* 3384 * When receiving packets from the peer we need to check whether we 3385 * need to forward the packets to the mux client. In this case we 3386 * restore the original channel id and keep track of CLOSE messages, 3387 * so we can cleanup the channel. 3388 */ 3389 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3390 return 0; 3391 if ((downstream = c->mux_ctx) == NULL) 3392 return 0; 3393 switch (type) { 3394 case SSH2_MSG_CHANNEL_CLOSE: 3395 case SSH2_MSG_CHANNEL_DATA: 3396 case SSH2_MSG_CHANNEL_EOF: 3397 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3398 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3399 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3400 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3401 case SSH2_MSG_CHANNEL_SUCCESS: 3402 case SSH2_MSG_CHANNEL_FAILURE: 3403 case SSH2_MSG_CHANNEL_REQUEST: 3404 break; 3405 default: 3406 debug2_f("channel %u: unsupported type %u", c->self, type); 3407 return 0; 3408 } 3409 if ((b = sshbuf_new()) == NULL) { 3410 error_f("alloc reply"); 3411 goto out; 3412 } 3413 /* get remaining payload (after id) */ 3414 cp = sshpkt_ptr(ssh, &len); 3415 if (cp == NULL) { 3416 error_f("no packet"); 3417 goto out; 3418 } 3419 /* translate id and send to muxclient */ 3420 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3421 (r = sshbuf_put_u8(b, type)) != 0 || 3422 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3423 (r = sshbuf_put(b, cp, len)) != 0 || 3424 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3425 error_fr(r, "compose muxclient"); 3426 goto out; 3427 } 3428 /* sshbuf_dump(b, stderr); */ 3429 if (ssh_packet_log_type(type)) 3430 debug3_f("channel %u: up->down: type %u", c->self, type); 3431 out: 3432 /* update state */ 3433 switch (type) { 3434 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3435 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3436 if (cp && len > 4) { 3437 c->remote_id = PEEK_U32(cp); 3438 c->have_remote_id = 1; 3439 } 3440 break; 3441 case SSH2_MSG_CHANNEL_CLOSE: 3442 if (c->flags & CHAN_CLOSE_SENT) 3443 channel_free(ssh, c); 3444 else 3445 c->flags |= CHAN_CLOSE_RCVD; 3446 break; 3447 } 3448 sshbuf_free(b); 3449 return 1; 3450 } 3451 3452 /* -- protocol input */ 3453 3454 /* Parse a channel ID from the current packet */ 3455 static int 3456 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3457 { 3458 uint32_t id; 3459 int r; 3460 3461 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3462 error_r(r, "%s: parse id", where); 3463 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3464 } 3465 if (id > INT_MAX) { 3466 error_r(r, "%s: bad channel id %u", where, id); 3467 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3468 } 3469 return (int)id; 3470 } 3471 3472 /* Lookup a channel from an ID in the current packet */ 3473 static Channel * 3474 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3475 { 3476 int id = channel_parse_id(ssh, where, what); 3477 Channel *c; 3478 3479 if ((c = channel_lookup(ssh, id)) == NULL) { 3480 ssh_packet_disconnect(ssh, 3481 "%s packet referred to nonexistent channel %d", what, id); 3482 } 3483 return c; 3484 } 3485 3486 int 3487 channel_input_data(int type, uint32_t seq, struct ssh *ssh) 3488 { 3489 const u_char *data; 3490 size_t data_len, win_len; 3491 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3492 int r; 3493 3494 if (channel_proxy_upstream(c, type, seq, ssh)) 3495 return 0; 3496 3497 /* Ignore any data for non-open channels (might happen on close) */ 3498 if (c->type != SSH_CHANNEL_OPEN && 3499 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3500 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3501 c->type != SSH_CHANNEL_X11_OPEN) 3502 return 0; 3503 3504 /* Get the data. */ 3505 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3506 (r = sshpkt_get_end(ssh)) != 0) 3507 fatal_fr(r, "channel %i: get data", c->self); 3508 3509 win_len = data_len; 3510 if (c->datagram) 3511 win_len += 4; /* string length header */ 3512 3513 /* 3514 * The sending side reduces its window as it sends data, so we 3515 * must 'fake' consumption of the data in order to ensure that window 3516 * updates are sent back. Otherwise the connection might deadlock. 3517 */ 3518 if (c->ostate != CHAN_OUTPUT_OPEN) { 3519 if (win_len > c->local_window) 3520 c->local_window = 0; 3521 else 3522 c->local_window -= win_len; 3523 c->local_consumed += win_len; 3524 return 0; 3525 } 3526 3527 if (win_len > c->local_maxpacket) { 3528 logit("channel %d: rcvd big packet %zu, maxpack %u", 3529 c->self, win_len, c->local_maxpacket); 3530 return 0; 3531 } 3532 if (win_len > c->local_window) { 3533 c->local_window_exceeded += win_len - c->local_window; 3534 logit("channel %d: rcvd too much data %zu, win %u/%u " 3535 "(excess %u)", c->self, win_len, c->local_window, 3536 c->local_window_max, c->local_window_exceeded); 3537 c->local_window = 0; 3538 /* Allow 10% grace before bringing the hammer down */ 3539 if (c->local_window_exceeded > (c->local_window_max / 10)) { 3540 ssh_packet_disconnect(ssh, "channel %d: peer ignored " 3541 "channel window", c->self); 3542 } 3543 } else { 3544 c->local_window -= win_len; 3545 c->local_window_exceeded = 0; 3546 } 3547 3548 if (c->datagram) { 3549 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3550 fatal_fr(r, "channel %i: append datagram", c->self); 3551 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3552 fatal_fr(r, "channel %i: append data", c->self); 3553 3554 return 0; 3555 } 3556 3557 int 3558 channel_input_extended_data(int type, uint32_t seq, struct ssh *ssh) 3559 { 3560 const u_char *data; 3561 size_t data_len; 3562 uint32_t tcode; 3563 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3564 int r; 3565 3566 if (channel_proxy_upstream(c, type, seq, ssh)) 3567 return 0; 3568 if (c->type != SSH_CHANNEL_OPEN) { 3569 logit("channel %d: ext data for non open", c->self); 3570 return 0; 3571 } 3572 if (c->flags & CHAN_EOF_RCVD) { 3573 if (ssh->compat & SSH_BUG_EXTEOF) 3574 debug("channel %d: accepting ext data after eof", 3575 c->self); 3576 else 3577 ssh_packet_disconnect(ssh, "Received extended_data " 3578 "after EOF on channel %d.", c->self); 3579 } 3580 3581 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3582 error_fr(r, "parse tcode"); 3583 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3584 } 3585 if (c->efd == -1 || 3586 c->extended_usage != CHAN_EXTENDED_WRITE || 3587 tcode != SSH2_EXTENDED_DATA_STDERR) { 3588 logit("channel %d: bad ext data", c->self); 3589 return 0; 3590 } 3591 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3592 (r = sshpkt_get_end(ssh)) != 0) { 3593 error_fr(r, "parse data"); 3594 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3595 } 3596 3597 if (data_len > c->local_window) { 3598 logit("channel %d: rcvd too much extended_data %zu, win %u", 3599 c->self, data_len, c->local_window); 3600 return 0; 3601 } 3602 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3603 /* XXX sshpkt_getb? */ 3604 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3605 error_fr(r, "append"); 3606 c->local_window -= data_len; 3607 return 0; 3608 } 3609 3610 int 3611 channel_input_ieof(int type, uint32_t seq, struct ssh *ssh) 3612 { 3613 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3614 int r; 3615 3616 if ((r = sshpkt_get_end(ssh)) != 0) { 3617 error_fr(r, "parse data"); 3618 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3619 } 3620 3621 if (channel_proxy_upstream(c, type, seq, ssh)) 3622 return 0; 3623 chan_rcvd_ieof(ssh, c); 3624 3625 /* XXX force input close */ 3626 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3627 debug("channel %d: FORCE input drain", c->self); 3628 c->istate = CHAN_INPUT_WAIT_DRAIN; 3629 if (sshbuf_len(c->input) == 0) 3630 chan_ibuf_empty(ssh, c); 3631 } 3632 return 0; 3633 } 3634 3635 int 3636 channel_input_oclose(int type, uint32_t seq, struct ssh *ssh) 3637 { 3638 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3639 int r; 3640 3641 if (channel_proxy_upstream(c, type, seq, ssh)) 3642 return 0; 3643 if ((r = sshpkt_get_end(ssh)) != 0) { 3644 error_fr(r, "parse data"); 3645 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3646 } 3647 chan_rcvd_oclose(ssh, c); 3648 return 0; 3649 } 3650 3651 int 3652 channel_input_open_confirmation(int type, uint32_t seq, struct ssh *ssh) 3653 { 3654 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3655 uint32_t remote_window, remote_maxpacket; 3656 int r; 3657 3658 if (channel_proxy_upstream(c, type, seq, ssh)) 3659 return 0; 3660 if (c->type != SSH_CHANNEL_OPENING) 3661 ssh_packet_disconnect(ssh, "Received open confirmation for " 3662 "non-opening channel %d.", c->self); 3663 /* 3664 * Record the remote channel number and mark that the channel 3665 * is now open. 3666 */ 3667 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3668 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3669 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3670 (r = sshpkt_get_end(ssh)) != 0) { 3671 error_fr(r, "window/maxpacket"); 3672 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3673 } 3674 3675 c->have_remote_id = 1; 3676 c->remote_window = remote_window; 3677 c->remote_maxpacket = remote_maxpacket; 3678 c->type = SSH_CHANNEL_OPEN; 3679 if (c->open_confirm) { 3680 debug2_f("channel %d: callback start", c->self); 3681 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3682 debug2_f("channel %d: callback done", c->self); 3683 } 3684 channel_set_used_time(ssh, c); 3685 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3686 c->remote_window, c->remote_maxpacket); 3687 return 0; 3688 } 3689 3690 static char * 3691 reason2txt(int reason) 3692 { 3693 switch (reason) { 3694 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3695 return "administratively prohibited"; 3696 case SSH2_OPEN_CONNECT_FAILED: 3697 return "connect failed"; 3698 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3699 return "unknown channel type"; 3700 case SSH2_OPEN_RESOURCE_SHORTAGE: 3701 return "resource shortage"; 3702 } 3703 return "unknown reason"; 3704 } 3705 3706 int 3707 channel_input_open_failure(int type, uint32_t seq, struct ssh *ssh) 3708 { 3709 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3710 uint32_t reason; 3711 char *msg = NULL; 3712 int r; 3713 3714 if (channel_proxy_upstream(c, type, seq, ssh)) 3715 return 0; 3716 if (c->type != SSH_CHANNEL_OPENING) 3717 ssh_packet_disconnect(ssh, "Received open failure for " 3718 "non-opening channel %d.", c->self); 3719 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3720 error_fr(r, "parse reason"); 3721 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3722 } 3723 /* skip language */ 3724 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3725 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3726 (r = sshpkt_get_end(ssh)) != 0) { 3727 error_fr(r, "parse msg/lang"); 3728 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3729 } 3730 logit("channel %d: open failed: %s%s%s", c->self, 3731 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3732 free(msg); 3733 if (c->open_confirm) { 3734 debug2_f("channel %d: callback start", c->self); 3735 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3736 debug2_f("channel %d: callback done", c->self); 3737 } 3738 /* Schedule the channel for cleanup/deletion. */ 3739 chan_mark_dead(ssh, c); 3740 return 0; 3741 } 3742 3743 int 3744 channel_input_window_adjust(int type, uint32_t seq, struct ssh *ssh) 3745 { 3746 int id = channel_parse_id(ssh, __func__, "window adjust"); 3747 Channel *c; 3748 uint32_t adjust; 3749 u_int new_rwin; 3750 int r; 3751 3752 if ((c = channel_lookup(ssh, id)) == NULL) { 3753 logit("Received window adjust for non-open channel %d.", id); 3754 return 0; 3755 } 3756 3757 if (channel_proxy_upstream(c, type, seq, ssh)) 3758 return 0; 3759 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3760 (r = sshpkt_get_end(ssh)) != 0) { 3761 error_fr(r, "parse adjust"); 3762 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3763 } 3764 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3765 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3766 fatal("channel %d: adjust %u overflows remote window %u", 3767 c->self, adjust, c->remote_window); 3768 } 3769 c->remote_window = new_rwin; 3770 return 0; 3771 } 3772 3773 int 3774 channel_input_status_confirm(int type, uint32_t seq, struct ssh *ssh) 3775 { 3776 int id = channel_parse_id(ssh, __func__, "status confirm"); 3777 Channel *c; 3778 struct channel_confirm *cc; 3779 3780 /* Reset keepalive timeout */ 3781 ssh_packet_set_alive_timeouts(ssh, 0); 3782 3783 debug2_f("type %d id %d", type, id); 3784 3785 if ((c = channel_lookup(ssh, id)) == NULL) { 3786 logit_f("%d: unknown", id); 3787 return 0; 3788 } 3789 if (channel_proxy_upstream(c, type, seq, ssh)) 3790 return 0; 3791 if (sshpkt_get_end(ssh) != 0) 3792 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3793 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3794 return 0; 3795 cc->cb(ssh, type, c, cc->ctx); 3796 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3797 freezero(cc, sizeof(*cc)); 3798 return 0; 3799 } 3800 3801 /* -- tcp forwarding */ 3802 3803 void 3804 channel_set_af(struct ssh *ssh, int af) 3805 { 3806 ssh->chanctxt->IPv4or6 = af; 3807 } 3808 3809 3810 /* 3811 * Determine whether or not a port forward listens to loopback, the 3812 * specified address or wildcard. On the client, a specified bind 3813 * address will always override gateway_ports. On the server, a 3814 * gateway_ports of 1 (``yes'') will override the client's specification 3815 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3816 * will bind to whatever address the client asked for. 3817 * 3818 * Special-case listen_addrs are: 3819 * 3820 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3821 * "" (empty string), "*" -> wildcard v4/v6 3822 * "localhost" -> loopback v4/v6 3823 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3824 */ 3825 static const char * 3826 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3827 int is_client, struct ForwardOptions *fwd_opts) 3828 { 3829 const char *addr = NULL; 3830 int wildcard = 0; 3831 3832 if (listen_addr == NULL) { 3833 /* No address specified: default to gateway_ports setting */ 3834 if (fwd_opts->gateway_ports) 3835 wildcard = 1; 3836 } else if (fwd_opts->gateway_ports || is_client) { 3837 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3838 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3839 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3840 (!is_client && fwd_opts->gateway_ports == 1)) { 3841 wildcard = 1; 3842 /* 3843 * Notify client if they requested a specific listen 3844 * address and it was overridden. 3845 */ 3846 if (*listen_addr != '\0' && 3847 strcmp(listen_addr, "0.0.0.0") != 0 && 3848 strcmp(listen_addr, "*") != 0) { 3849 ssh_packet_send_debug(ssh, 3850 "Forwarding listen address " 3851 "\"%s\" overridden by server " 3852 "GatewayPorts", listen_addr); 3853 } 3854 } else if (strcmp(listen_addr, "localhost") != 0 || 3855 strcmp(listen_addr, "127.0.0.1") == 0 || 3856 strcmp(listen_addr, "::1") == 0) { 3857 /* 3858 * Accept explicit localhost address when 3859 * GatewayPorts=yes. The "localhost" hostname is 3860 * deliberately skipped here so it will listen on all 3861 * available local address families. 3862 */ 3863 addr = listen_addr; 3864 } 3865 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3866 strcmp(listen_addr, "::1") == 0) { 3867 /* 3868 * If a specific IPv4/IPv6 localhost address has been 3869 * requested then accept it even if gateway_ports is in 3870 * effect. This allows the client to prefer IPv4 or IPv6. 3871 */ 3872 addr = listen_addr; 3873 } 3874 if (wildcardp != NULL) 3875 *wildcardp = wildcard; 3876 return addr; 3877 } 3878 3879 static int 3880 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3881 struct Forward *fwd, int *allocated_listen_port, 3882 struct ForwardOptions *fwd_opts) 3883 { 3884 Channel *c; 3885 int sock, r, success = 0, wildcard = 0, is_client; 3886 struct addrinfo hints, *ai, *aitop; 3887 const char *host, *addr; 3888 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3889 in_port_t *lport_p; 3890 3891 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3892 3893 if (is_client && fwd->connect_path != NULL) { 3894 host = fwd->connect_path; 3895 } else { 3896 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3897 fwd->listen_host : fwd->connect_host; 3898 if (host == NULL) { 3899 error("No forward host name."); 3900 return 0; 3901 } 3902 if (strlen(host) >= NI_MAXHOST) { 3903 error("Forward host name too long."); 3904 return 0; 3905 } 3906 } 3907 3908 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3909 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3910 is_client, fwd_opts); 3911 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3912 (addr == NULL) ? "NULL" : addr); 3913 3914 /* 3915 * getaddrinfo returns a loopback address if the hostname is 3916 * set to NULL and hints.ai_flags is not AI_PASSIVE 3917 */ 3918 memset(&hints, 0, sizeof(hints)); 3919 hints.ai_family = ssh->chanctxt->IPv4or6; 3920 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3921 hints.ai_socktype = SOCK_STREAM; 3922 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3923 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3924 if (addr == NULL) { 3925 /* This really shouldn't happen */ 3926 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3927 ssh_gai_strerror(r)); 3928 } else { 3929 error_f("getaddrinfo(%.64s): %s", addr, 3930 ssh_gai_strerror(r)); 3931 } 3932 return 0; 3933 } 3934 if (allocated_listen_port != NULL) 3935 *allocated_listen_port = 0; 3936 for (ai = aitop; ai; ai = ai->ai_next) { 3937 switch (ai->ai_family) { 3938 case AF_INET: 3939 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3940 sin_port; 3941 break; 3942 case AF_INET6: 3943 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3944 sin6_port; 3945 break; 3946 default: 3947 continue; 3948 } 3949 /* 3950 * If allocating a port for -R forwards, then use the 3951 * same port for all address families. 3952 */ 3953 if (type == SSH_CHANNEL_RPORT_LISTENER && 3954 fwd->listen_port == 0 && allocated_listen_port != NULL && 3955 *allocated_listen_port > 0) 3956 *lport_p = htons(*allocated_listen_port); 3957 3958 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3959 strport, sizeof(strport), 3960 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3961 error_f("getnameinfo failed"); 3962 continue; 3963 } 3964 /* Create a port to listen for the host. */ 3965 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3966 if (sock == -1) { 3967 /* this is no error since kernel may not support ipv6 */ 3968 verbose("socket [%s]:%s: %.100s", ntop, strport, 3969 strerror(errno)); 3970 continue; 3971 } 3972 3973 set_reuseaddr(sock); 3974 if (ai->ai_family == AF_INET6) 3975 sock_set_v6only(sock); 3976 3977 debug("Local forwarding listening on %s port %s.", 3978 ntop, strport); 3979 3980 /* Bind the socket to the address. */ 3981 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3982 /* 3983 * address can be in if use ipv6 address is 3984 * already bound 3985 */ 3986 if (!ai->ai_next) 3987 error("bind [%s]:%s: %.100s", 3988 ntop, strport, strerror(errno)); 3989 else 3990 verbose("bind [%s]:%s: %.100s", 3991 ntop, strport, strerror(errno)); 3992 3993 close(sock); 3994 continue; 3995 } 3996 /* Start listening for connections on the socket. */ 3997 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3998 error("listen [%s]:%s: %.100s", ntop, strport, 3999 strerror(errno)); 4000 close(sock); 4001 continue; 4002 } 4003 4004 /* 4005 * fwd->listen_port == 0 requests a dynamically allocated port - 4006 * record what we got. 4007 */ 4008 if (type == SSH_CHANNEL_RPORT_LISTENER && 4009 fwd->listen_port == 0 && 4010 allocated_listen_port != NULL && 4011 *allocated_listen_port == 0) { 4012 *allocated_listen_port = get_local_port(sock); 4013 debug("Allocated listen port %d", 4014 *allocated_listen_port); 4015 } 4016 4017 /* Allocate a channel number for the socket. */ 4018 c = channel_new(ssh, "port-listener", type, sock, sock, -1, 4019 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 4020 0, "port listener", 1); 4021 c->path = xstrdup(host); 4022 c->host_port = fwd->connect_port; 4023 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 4024 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 4025 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 4026 c->listening_port = *allocated_listen_port; 4027 else 4028 c->listening_port = fwd->listen_port; 4029 success = 1; 4030 } 4031 if (success == 0) 4032 error_f("cannot listen to port: %d", fwd->listen_port); 4033 freeaddrinfo(aitop); 4034 return success; 4035 } 4036 4037 static int 4038 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 4039 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4040 { 4041 struct sockaddr_un sunaddr; 4042 const char *path; 4043 Channel *c; 4044 int port, sock; 4045 mode_t omask; 4046 4047 switch (type) { 4048 case SSH_CHANNEL_UNIX_LISTENER: 4049 if (fwd->connect_path != NULL) { 4050 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 4051 error("Local connecting path too long: %s", 4052 fwd->connect_path); 4053 return 0; 4054 } 4055 path = fwd->connect_path; 4056 port = PORT_STREAMLOCAL; 4057 } else { 4058 if (fwd->connect_host == NULL) { 4059 error("No forward host name."); 4060 return 0; 4061 } 4062 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 4063 error("Forward host name too long."); 4064 return 0; 4065 } 4066 path = fwd->connect_host; 4067 port = fwd->connect_port; 4068 } 4069 break; 4070 case SSH_CHANNEL_RUNIX_LISTENER: 4071 path = fwd->listen_path; 4072 port = PORT_STREAMLOCAL; 4073 break; 4074 default: 4075 error_f("unexpected channel type %d", type); 4076 return 0; 4077 } 4078 4079 if (fwd->listen_path == NULL) { 4080 error("No forward path name."); 4081 return 0; 4082 } 4083 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 4084 error("Local listening path too long: %s", fwd->listen_path); 4085 return 0; 4086 } 4087 4088 debug3_f("type %d path %s", type, fwd->listen_path); 4089 4090 /* Start a Unix domain listener. */ 4091 omask = umask(fwd_opts->streamlocal_bind_mask); 4092 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 4093 fwd_opts->streamlocal_bind_unlink); 4094 umask(omask); 4095 if (sock < 0) 4096 return 0; 4097 4098 debug("Local forwarding listening on path %s.", fwd->listen_path); 4099 4100 /* Allocate a channel number for the socket. */ 4101 c = channel_new(ssh, "unix-listener", type, sock, sock, -1, 4102 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 4103 0, "unix listener", 1); 4104 c->path = xstrdup(path); 4105 c->host_port = port; 4106 c->listening_port = PORT_STREAMLOCAL; 4107 c->listening_addr = xstrdup(fwd->listen_path); 4108 return 1; 4109 } 4110 4111 static int 4112 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 4113 const char *host, u_short port) 4114 { 4115 u_int i; 4116 int found = 0; 4117 4118 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4119 Channel *c = ssh->chanctxt->channels[i]; 4120 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 4121 continue; 4122 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 4123 debug2_f("close channel %d", i); 4124 channel_free(ssh, c); 4125 found = 1; 4126 } 4127 } 4128 4129 return found; 4130 } 4131 4132 static int 4133 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 4134 { 4135 u_int i; 4136 int found = 0; 4137 4138 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4139 Channel *c = ssh->chanctxt->channels[i]; 4140 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 4141 continue; 4142 if (c->path == NULL) 4143 continue; 4144 if (strcmp(c->path, path) == 0) { 4145 debug2_f("close channel %d", i); 4146 channel_free(ssh, c); 4147 found = 1; 4148 } 4149 } 4150 4151 return found; 4152 } 4153 4154 int 4155 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 4156 { 4157 if (fwd->listen_path != NULL) { 4158 return channel_cancel_rport_listener_streamlocal(ssh, 4159 fwd->listen_path); 4160 } else { 4161 return channel_cancel_rport_listener_tcpip(ssh, 4162 fwd->listen_host, fwd->listen_port); 4163 } 4164 } 4165 4166 static int 4167 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 4168 const char *lhost, u_short lport, int cport, 4169 struct ForwardOptions *fwd_opts) 4170 { 4171 u_int i; 4172 int found = 0; 4173 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 4174 4175 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4176 Channel *c = ssh->chanctxt->channels[i]; 4177 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 4178 continue; 4179 if (c->listening_port != lport) 4180 continue; 4181 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 4182 /* skip dynamic forwardings */ 4183 if (c->host_port == 0) 4184 continue; 4185 } else { 4186 if (c->host_port != cport) 4187 continue; 4188 } 4189 if ((c->listening_addr == NULL && addr != NULL) || 4190 (c->listening_addr != NULL && addr == NULL)) 4191 continue; 4192 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 4193 debug2_f("close channel %d", i); 4194 channel_free(ssh, c); 4195 found = 1; 4196 } 4197 } 4198 4199 return found; 4200 } 4201 4202 static int 4203 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 4204 { 4205 u_int i; 4206 int found = 0; 4207 4208 if (path == NULL) { 4209 error_f("no path specified."); 4210 return 0; 4211 } 4212 4213 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 4214 Channel *c = ssh->chanctxt->channels[i]; 4215 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 4216 continue; 4217 if (c->listening_addr == NULL) 4218 continue; 4219 if (strcmp(c->listening_addr, path) == 0) { 4220 debug2_f("close channel %d", i); 4221 channel_free(ssh, c); 4222 found = 1; 4223 } 4224 } 4225 4226 return found; 4227 } 4228 4229 int 4230 channel_cancel_lport_listener(struct ssh *ssh, 4231 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 4232 { 4233 if (fwd->listen_path != NULL) { 4234 return channel_cancel_lport_listener_streamlocal(ssh, 4235 fwd->listen_path); 4236 } else { 4237 return channel_cancel_lport_listener_tcpip(ssh, 4238 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 4239 } 4240 } 4241 4242 /* protocol local port fwd, used by ssh */ 4243 int 4244 channel_setup_local_fwd_listener(struct ssh *ssh, 4245 struct Forward *fwd, struct ForwardOptions *fwd_opts) 4246 { 4247 if (fwd->listen_path != NULL) { 4248 return channel_setup_fwd_listener_streamlocal(ssh, 4249 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 4250 } else { 4251 return channel_setup_fwd_listener_tcpip(ssh, 4252 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 4253 } 4254 } 4255 4256 /* Matches a remote forwarding permission against a requested forwarding */ 4257 static int 4258 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 4259 { 4260 int ret; 4261 char *lhost; 4262 4263 /* XXX add ACLs for streamlocal */ 4264 if (fwd->listen_path != NULL) 4265 return 1; 4266 4267 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 4268 return 0; 4269 4270 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 4271 allowed_open->listen_port != fwd->listen_port) 4272 return 0; 4273 4274 /* Match hostnames case-insensitively */ 4275 lhost = xstrdup(fwd->listen_host); 4276 lowercase(lhost); 4277 ret = match_pattern(lhost, allowed_open->listen_host); 4278 free(lhost); 4279 4280 return ret; 4281 } 4282 4283 /* Checks whether a requested remote forwarding is permitted */ 4284 static int 4285 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 4286 { 4287 struct ssh_channels *sc = ssh->chanctxt; 4288 struct permission_set *pset = &sc->remote_perms; 4289 u_int i, permit, permit_adm = 1; 4290 struct permission *perm; 4291 4292 /* XXX apply GatewayPorts override before checking? */ 4293 4294 permit = pset->all_permitted; 4295 if (!permit) { 4296 for (i = 0; i < pset->num_permitted_user; i++) { 4297 perm = &pset->permitted_user[i]; 4298 if (remote_open_match(perm, fwd)) { 4299 permit = 1; 4300 break; 4301 } 4302 } 4303 } 4304 4305 if (pset->num_permitted_admin > 0) { 4306 permit_adm = 0; 4307 for (i = 0; i < pset->num_permitted_admin; i++) { 4308 perm = &pset->permitted_admin[i]; 4309 if (remote_open_match(perm, fwd)) { 4310 permit_adm = 1; 4311 break; 4312 } 4313 } 4314 } 4315 4316 return permit && permit_adm; 4317 } 4318 4319 /* protocol v2 remote port fwd, used by sshd */ 4320 int 4321 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4322 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4323 { 4324 if (!check_rfwd_permission(ssh, fwd)) { 4325 ssh_packet_send_debug(ssh, "port forwarding refused"); 4326 if (fwd->listen_path != NULL) 4327 /* XXX always allowed, see remote_open_match() */ 4328 logit("Received request from %.100s port %d to " 4329 "remote forward to path \"%.100s\", " 4330 "but the request was denied.", 4331 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4332 fwd->listen_path); 4333 else if(fwd->listen_host != NULL) 4334 logit("Received request from %.100s port %d to " 4335 "remote forward to host %.100s port %d, " 4336 "but the request was denied.", 4337 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4338 fwd->listen_host, fwd->listen_port ); 4339 else 4340 logit("Received request from %.100s port %d to remote " 4341 "forward, but the request was denied.", 4342 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4343 return 0; 4344 } 4345 if (fwd->listen_path != NULL) { 4346 return channel_setup_fwd_listener_streamlocal(ssh, 4347 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4348 } else { 4349 return channel_setup_fwd_listener_tcpip(ssh, 4350 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4351 fwd_opts); 4352 } 4353 } 4354 4355 /* 4356 * Translate the requested rfwd listen host to something usable for 4357 * this server. 4358 */ 4359 static const char * 4360 channel_rfwd_bind_host(const char *listen_host) 4361 { 4362 if (listen_host == NULL) { 4363 return "localhost"; 4364 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4365 return ""; 4366 } else 4367 return listen_host; 4368 } 4369 4370 /* 4371 * Initiate forwarding of connections to port "port" on remote host through 4372 * the secure channel to host:port from local side. 4373 * Returns handle (index) for updating the dynamic listen port with 4374 * channel_update_permission(). 4375 */ 4376 int 4377 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4378 { 4379 int r, success = 0, idx = -1; 4380 const char *host_to_connect, *listen_host, *listen_path; 4381 int port_to_connect, listen_port; 4382 4383 /* Send the forward request to the remote side. */ 4384 if (fwd->listen_path != NULL) { 4385 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4386 (r = sshpkt_put_cstring(ssh, 4387 "streamlocal-forward@openssh.com")) != 0 || 4388 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4389 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4390 (r = sshpkt_send(ssh)) != 0 || 4391 (r = ssh_packet_write_wait(ssh)) != 0) 4392 fatal_fr(r, "request streamlocal"); 4393 } else { 4394 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4395 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4396 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4397 (r = sshpkt_put_cstring(ssh, 4398 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4399 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4400 (r = sshpkt_send(ssh)) != 0 || 4401 (r = ssh_packet_write_wait(ssh)) != 0) 4402 fatal_fr(r, "request tcpip-forward"); 4403 } 4404 /* Assume that server accepts the request */ 4405 success = 1; 4406 if (success) { 4407 /* Record that connection to this host/port is permitted. */ 4408 host_to_connect = listen_host = listen_path = NULL; 4409 port_to_connect = listen_port = 0; 4410 if (fwd->connect_path != NULL) { 4411 host_to_connect = fwd->connect_path; 4412 port_to_connect = PORT_STREAMLOCAL; 4413 } else { 4414 host_to_connect = fwd->connect_host; 4415 port_to_connect = fwd->connect_port; 4416 } 4417 if (fwd->listen_path != NULL) { 4418 listen_path = fwd->listen_path; 4419 listen_port = PORT_STREAMLOCAL; 4420 } else { 4421 listen_host = fwd->listen_host; 4422 listen_port = fwd->listen_port; 4423 } 4424 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4425 host_to_connect, port_to_connect, 4426 listen_host, listen_path, listen_port, NULL); 4427 } 4428 return idx; 4429 } 4430 4431 static int 4432 open_match(struct permission *allowed_open, const char *requestedhost, 4433 int requestedport) 4434 { 4435 if (allowed_open->host_to_connect == NULL) 4436 return 0; 4437 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4438 allowed_open->port_to_connect != requestedport) 4439 return 0; 4440 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4441 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4442 return 0; 4443 return 1; 4444 } 4445 4446 /* 4447 * Note that in the listen host/port case 4448 * we don't support FWD_PERMIT_ANY_PORT and 4449 * need to translate between the configured-host (listen_host) 4450 * and what we've sent to the remote server (channel_rfwd_bind_host) 4451 */ 4452 static int 4453 open_listen_match_tcpip(struct permission *allowed_open, 4454 const char *requestedhost, u_short requestedport, int translate) 4455 { 4456 const char *allowed_host; 4457 4458 if (allowed_open->host_to_connect == NULL) 4459 return 0; 4460 if (allowed_open->listen_port != requestedport) 4461 return 0; 4462 if (!translate && allowed_open->listen_host == NULL && 4463 requestedhost == NULL) 4464 return 1; 4465 allowed_host = translate ? 4466 channel_rfwd_bind_host(allowed_open->listen_host) : 4467 allowed_open->listen_host; 4468 if (allowed_host == NULL || requestedhost == NULL || 4469 strcmp(allowed_host, requestedhost) != 0) 4470 return 0; 4471 return 1; 4472 } 4473 4474 static int 4475 open_listen_match_streamlocal(struct permission *allowed_open, 4476 const char *requestedpath) 4477 { 4478 if (allowed_open->host_to_connect == NULL) 4479 return 0; 4480 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4481 return 0; 4482 if (allowed_open->listen_path == NULL || 4483 strcmp(allowed_open->listen_path, requestedpath) != 0) 4484 return 0; 4485 return 1; 4486 } 4487 4488 /* 4489 * Request cancellation of remote forwarding of connection host:port from 4490 * local side. 4491 */ 4492 static int 4493 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4494 const char *host, u_short port) 4495 { 4496 struct ssh_channels *sc = ssh->chanctxt; 4497 struct permission_set *pset = &sc->local_perms; 4498 int r; 4499 u_int i; 4500 struct permission *perm = NULL; 4501 4502 for (i = 0; i < pset->num_permitted_user; i++) { 4503 perm = &pset->permitted_user[i]; 4504 if (open_listen_match_tcpip(perm, host, port, 0)) 4505 break; 4506 perm = NULL; 4507 } 4508 if (perm == NULL) { 4509 debug_f("requested forward not found"); 4510 return -1; 4511 } 4512 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4513 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4514 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4515 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4516 (r = sshpkt_put_u32(ssh, port)) != 0 || 4517 (r = sshpkt_send(ssh)) != 0) 4518 fatal_fr(r, "send cancel"); 4519 4520 fwd_perm_clear(perm); /* unregister */ 4521 4522 return 0; 4523 } 4524 4525 /* 4526 * Request cancellation of remote forwarding of Unix domain socket 4527 * path from local side. 4528 */ 4529 static int 4530 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4531 { 4532 struct ssh_channels *sc = ssh->chanctxt; 4533 struct permission_set *pset = &sc->local_perms; 4534 int r; 4535 u_int i; 4536 struct permission *perm = NULL; 4537 4538 for (i = 0; i < pset->num_permitted_user; i++) { 4539 perm = &pset->permitted_user[i]; 4540 if (open_listen_match_streamlocal(perm, path)) 4541 break; 4542 perm = NULL; 4543 } 4544 if (perm == NULL) { 4545 debug_f("requested forward not found"); 4546 return -1; 4547 } 4548 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4549 (r = sshpkt_put_cstring(ssh, 4550 "cancel-streamlocal-forward@openssh.com")) != 0 || 4551 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4552 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4553 (r = sshpkt_send(ssh)) != 0) 4554 fatal_fr(r, "send cancel"); 4555 4556 fwd_perm_clear(perm); /* unregister */ 4557 4558 return 0; 4559 } 4560 4561 /* 4562 * Request cancellation of remote forwarding of a connection from local side. 4563 */ 4564 int 4565 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4566 { 4567 if (fwd->listen_path != NULL) { 4568 return channel_request_rforward_cancel_streamlocal(ssh, 4569 fwd->listen_path); 4570 } else { 4571 return channel_request_rforward_cancel_tcpip(ssh, 4572 fwd->listen_host, 4573 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4574 } 4575 } 4576 4577 /* 4578 * Permits opening to any host/port if permitted_user[] is empty. This is 4579 * usually called by the server, because the user could connect to any port 4580 * anyway, and the server has no way to know but to trust the client anyway. 4581 */ 4582 void 4583 channel_permit_all(struct ssh *ssh, int where) 4584 { 4585 struct permission_set *pset = permission_set_get(ssh, where); 4586 4587 if (pset->num_permitted_user == 0) 4588 pset->all_permitted = 1; 4589 } 4590 4591 /* 4592 * Permit the specified host/port for forwarding. 4593 */ 4594 void 4595 channel_add_permission(struct ssh *ssh, int who, int where, 4596 char *host, int port) 4597 { 4598 int local = where == FORWARD_LOCAL; 4599 struct permission_set *pset = permission_set_get(ssh, where); 4600 4601 debug("allow %s forwarding to host %s port %d", 4602 fwd_ident(who, where), host, port); 4603 /* 4604 * Remote forwards set listen_host/port, local forwards set 4605 * host/port_to_connect. 4606 */ 4607 permission_set_add(ssh, who, where, 4608 local ? host : NULL, local ? port : 0, 4609 local ? NULL : host, NULL, local ? 0 : port, NULL); 4610 pset->all_permitted = 0; 4611 } 4612 4613 /* 4614 * Administratively disable forwarding. 4615 */ 4616 void 4617 channel_disable_admin(struct ssh *ssh, int where) 4618 { 4619 channel_clear_permission(ssh, FORWARD_ADM, where); 4620 permission_set_add(ssh, FORWARD_ADM, where, 4621 NULL, 0, NULL, NULL, 0, NULL); 4622 } 4623 4624 /* 4625 * Clear a list of permitted opens. 4626 */ 4627 void 4628 channel_clear_permission(struct ssh *ssh, int who, int where) 4629 { 4630 struct permission **permp; 4631 u_int i, *npermp; 4632 4633 permission_set_get_array(ssh, who, where, &permp, &npermp); 4634 for (i = 0; i < *npermp; i++) 4635 fwd_perm_clear((*permp) + i); 4636 free(*permp); 4637 *permp = NULL; 4638 *npermp = 0; 4639 } 4640 4641 /* 4642 * Update the listen port for a dynamic remote forward, after 4643 * the actual 'newport' has been allocated. If 'newport' < 0 is 4644 * passed then they entry will be invalidated. 4645 */ 4646 void 4647 channel_update_permission(struct ssh *ssh, int idx, int newport) 4648 { 4649 struct permission_set *pset = &ssh->chanctxt->local_perms; 4650 4651 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4652 debug_f("index out of range: %d num_permitted_user %d", 4653 idx, pset->num_permitted_user); 4654 return; 4655 } 4656 debug("%s allowed port %d for forwarding to host %s port %d", 4657 newport > 0 ? "Updating" : "Removing", 4658 newport, 4659 pset->permitted_user[idx].host_to_connect, 4660 pset->permitted_user[idx].port_to_connect); 4661 if (newport <= 0) 4662 fwd_perm_clear(&pset->permitted_user[idx]); 4663 else { 4664 pset->permitted_user[idx].listen_port = 4665 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4666 } 4667 } 4668 4669 /* Try to start non-blocking connect to next host in cctx list */ 4670 static int 4671 connect_next(struct channel_connect *cctx) 4672 { 4673 int sock, saved_errno; 4674 struct sockaddr_un *sunaddr; 4675 char ntop[NI_MAXHOST]; 4676 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4677 4678 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4679 switch (cctx->ai->ai_family) { 4680 case AF_UNIX: 4681 /* unix:pathname instead of host:port */ 4682 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4683 strlcpy(ntop, "unix", sizeof(ntop)); 4684 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4685 break; 4686 case AF_INET: 4687 case AF_INET6: 4688 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4689 ntop, sizeof(ntop), strport, sizeof(strport), 4690 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4691 error_f("getnameinfo failed"); 4692 continue; 4693 } 4694 break; 4695 default: 4696 continue; 4697 } 4698 debug_f("start for host %.100s ([%.100s]:%s)", 4699 cctx->host, ntop, strport); 4700 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4701 cctx->ai->ai_protocol)) == -1) { 4702 if (cctx->ai->ai_next == NULL) 4703 error("socket: %.100s", strerror(errno)); 4704 else 4705 verbose("socket: %.100s", strerror(errno)); 4706 continue; 4707 } 4708 if (set_nonblock(sock) == -1) 4709 fatal_f("set_nonblock(%d)", sock); 4710 if (connect(sock, cctx->ai->ai_addr, 4711 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4712 debug_f("host %.100s ([%.100s]:%s): %.100s", 4713 cctx->host, ntop, strport, strerror(errno)); 4714 saved_errno = errno; 4715 close(sock); 4716 errno = saved_errno; 4717 continue; /* fail -- try next */ 4718 } 4719 if (cctx->ai->ai_family != AF_UNIX) 4720 set_nodelay(sock); 4721 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4722 cctx->host, ntop, strport, sock); 4723 cctx->ai = cctx->ai->ai_next; 4724 return sock; 4725 } 4726 return -1; 4727 } 4728 4729 static void 4730 channel_connect_ctx_free(struct channel_connect *cctx) 4731 { 4732 free(cctx->host); 4733 if (cctx->aitop) { 4734 if (cctx->aitop->ai_family == AF_UNIX) 4735 free(cctx->aitop); 4736 else 4737 freeaddrinfo(cctx->aitop); 4738 } 4739 memset(cctx, 0, sizeof(*cctx)); 4740 } 4741 4742 /* 4743 * Return connecting socket to remote host:port or local socket path, 4744 * passing back the failure reason if appropriate. 4745 */ 4746 static int 4747 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4748 char *ctype, char *rname, struct channel_connect *cctx, 4749 int *reason, const char **errmsg) 4750 { 4751 struct addrinfo hints; 4752 int gaierr; 4753 int sock = -1; 4754 char strport[NI_MAXSERV]; 4755 4756 if (port == PORT_STREAMLOCAL) { 4757 struct sockaddr_un *sunaddr; 4758 struct addrinfo *ai; 4759 4760 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4761 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4762 return -1; 4763 } 4764 4765 /* 4766 * Fake up a struct addrinfo for AF_UNIX connections. 4767 * channel_connect_ctx_free() must check ai_family 4768 * and use free() not freeaddrinfo() for AF_UNIX. 4769 */ 4770 ai = xcalloc(1, sizeof(*ai) + sizeof(*sunaddr)); 4771 ai->ai_addr = (struct sockaddr *)(ai + 1); 4772 ai->ai_addrlen = sizeof(*sunaddr); 4773 ai->ai_family = AF_UNIX; 4774 ai->ai_socktype = socktype; 4775 ai->ai_protocol = PF_UNSPEC; 4776 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4777 sunaddr->sun_family = AF_UNIX; 4778 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4779 cctx->aitop = ai; 4780 } else { 4781 memset(&hints, 0, sizeof(hints)); 4782 hints.ai_family = ssh->chanctxt->IPv4or6; 4783 hints.ai_socktype = socktype; 4784 snprintf(strport, sizeof strport, "%d", port); 4785 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4786 != 0) { 4787 if (errmsg != NULL) 4788 *errmsg = ssh_gai_strerror(gaierr); 4789 if (reason != NULL) 4790 *reason = SSH2_OPEN_CONNECT_FAILED; 4791 error("connect_to %.100s: unknown host (%s)", name, 4792 ssh_gai_strerror(gaierr)); 4793 return -1; 4794 } 4795 } 4796 4797 cctx->host = xstrdup(name); 4798 cctx->port = port; 4799 cctx->ai = cctx->aitop; 4800 4801 if ((sock = connect_next(cctx)) == -1) { 4802 error("connect to %.100s port %d failed: %s", 4803 name, port, strerror(errno)); 4804 return -1; 4805 } 4806 4807 return sock; 4808 } 4809 4810 /* Return CONNECTING channel to remote host:port or local socket path */ 4811 static Channel * 4812 connect_to(struct ssh *ssh, const char *host, int port, 4813 char *ctype, char *rname) 4814 { 4815 struct channel_connect cctx; 4816 Channel *c; 4817 int sock; 4818 4819 memset(&cctx, 0, sizeof(cctx)); 4820 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4821 &cctx, NULL, NULL); 4822 if (sock == -1) { 4823 channel_connect_ctx_free(&cctx); 4824 return NULL; 4825 } 4826 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4827 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4828 c->host_port = port; 4829 c->path = xstrdup(host); 4830 c->connect_ctx = cctx; 4831 4832 return c; 4833 } 4834 4835 /* 4836 * returns either the newly connected channel or the downstream channel 4837 * that needs to deal with this connection. 4838 */ 4839 Channel * 4840 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4841 u_short listen_port, char *ctype, char *rname) 4842 { 4843 struct ssh_channels *sc = ssh->chanctxt; 4844 struct permission_set *pset = &sc->local_perms; 4845 u_int i; 4846 struct permission *perm; 4847 4848 for (i = 0; i < pset->num_permitted_user; i++) { 4849 perm = &pset->permitted_user[i]; 4850 if (open_listen_match_tcpip(perm, 4851 listen_host, listen_port, 1)) { 4852 if (perm->downstream) 4853 return perm->downstream; 4854 if (perm->port_to_connect == 0) 4855 return rdynamic_connect_prepare(ssh, 4856 ctype, rname); 4857 return connect_to(ssh, 4858 perm->host_to_connect, perm->port_to_connect, 4859 ctype, rname); 4860 } 4861 } 4862 error("WARNING: Server requests forwarding for unknown listen_port %d", 4863 listen_port); 4864 return NULL; 4865 } 4866 4867 Channel * 4868 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4869 char *ctype, char *rname) 4870 { 4871 struct ssh_channels *sc = ssh->chanctxt; 4872 struct permission_set *pset = &sc->local_perms; 4873 u_int i; 4874 struct permission *perm; 4875 4876 for (i = 0; i < pset->num_permitted_user; i++) { 4877 perm = &pset->permitted_user[i]; 4878 if (open_listen_match_streamlocal(perm, path)) { 4879 return connect_to(ssh, 4880 perm->host_to_connect, perm->port_to_connect, 4881 ctype, rname); 4882 } 4883 } 4884 error("WARNING: Server requests forwarding for unknown path %.100s", 4885 path); 4886 return NULL; 4887 } 4888 4889 /* Check if connecting to that port is permitted and connect. */ 4890 Channel * 4891 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4892 char *ctype, char *rname, int *reason, const char **errmsg) 4893 { 4894 struct ssh_channels *sc = ssh->chanctxt; 4895 struct permission_set *pset = &sc->local_perms; 4896 struct channel_connect cctx; 4897 Channel *c; 4898 u_int i, permit, permit_adm = 1; 4899 int sock; 4900 struct permission *perm; 4901 4902 permit = pset->all_permitted; 4903 if (!permit) { 4904 for (i = 0; i < pset->num_permitted_user; i++) { 4905 perm = &pset->permitted_user[i]; 4906 if (open_match(perm, host, port)) { 4907 permit = 1; 4908 break; 4909 } 4910 } 4911 } 4912 4913 if (pset->num_permitted_admin > 0) { 4914 permit_adm = 0; 4915 for (i = 0; i < pset->num_permitted_admin; i++) { 4916 perm = &pset->permitted_admin[i]; 4917 if (open_match(perm, host, port)) { 4918 permit_adm = 1; 4919 break; 4920 } 4921 } 4922 } 4923 4924 if (!permit || !permit_adm) { 4925 logit("Received request from %.100s port %d to connect to " 4926 "host %.100s port %d, but the request was denied.", 4927 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4928 if (reason != NULL) 4929 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4930 return NULL; 4931 } 4932 4933 memset(&cctx, 0, sizeof(cctx)); 4934 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4935 &cctx, reason, errmsg); 4936 if (sock == -1) { 4937 channel_connect_ctx_free(&cctx); 4938 return NULL; 4939 } 4940 4941 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4942 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4943 c->host_port = port; 4944 c->path = xstrdup(host); 4945 c->connect_ctx = cctx; 4946 4947 return c; 4948 } 4949 4950 /* Check if connecting to that path is permitted and connect. */ 4951 Channel * 4952 channel_connect_to_path(struct ssh *ssh, const char *path, 4953 char *ctype, char *rname) 4954 { 4955 struct ssh_channels *sc = ssh->chanctxt; 4956 struct permission_set *pset = &sc->local_perms; 4957 u_int i, permit, permit_adm = 1; 4958 struct permission *perm; 4959 4960 permit = pset->all_permitted; 4961 if (!permit) { 4962 for (i = 0; i < pset->num_permitted_user; i++) { 4963 perm = &pset->permitted_user[i]; 4964 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4965 permit = 1; 4966 break; 4967 } 4968 } 4969 } 4970 4971 if (pset->num_permitted_admin > 0) { 4972 permit_adm = 0; 4973 for (i = 0; i < pset->num_permitted_admin; i++) { 4974 perm = &pset->permitted_admin[i]; 4975 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4976 permit_adm = 1; 4977 break; 4978 } 4979 } 4980 } 4981 4982 if (!permit || !permit_adm) { 4983 logit("Received request to connect to path %.100s, " 4984 "but the request was denied.", path); 4985 return NULL; 4986 } 4987 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4988 } 4989 4990 void 4991 channel_send_window_changes(struct ssh *ssh) 4992 { 4993 struct ssh_channels *sc = ssh->chanctxt; 4994 struct winsize ws; 4995 int r; 4996 u_int i; 4997 4998 for (i = 0; i < sc->channels_alloc; i++) { 4999 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 5000 sc->channels[i]->type != SSH_CHANNEL_OPEN) 5001 continue; 5002 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 5003 continue; 5004 channel_request_start(ssh, i, "window-change", 0); 5005 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 5006 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 5007 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 5008 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 5009 (r = sshpkt_send(ssh)) != 0) 5010 fatal_fr(r, "channel %u; send window-change", i); 5011 } 5012 } 5013 5014 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 5015 static Channel * 5016 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 5017 { 5018 Channel *c; 5019 int r; 5020 5021 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 5022 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 5023 c->host_port = 0; 5024 c->path = NULL; 5025 5026 /* 5027 * We need to open the channel before we have a FD, 5028 * so that we can get SOCKS header from peer. 5029 */ 5030 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 5031 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 5032 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 5033 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 5034 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 5035 fatal_fr(r, "channel %i; confirm", c->self); 5036 return c; 5037 } 5038 5039 /* Return CONNECTING socket to remote host:port or local socket path */ 5040 static int 5041 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 5042 { 5043 struct ssh_channels *sc = ssh->chanctxt; 5044 struct permission_set *pset = &sc->local_perms; 5045 struct permission *perm; 5046 struct channel_connect cctx; 5047 u_int i, permit_adm = 1; 5048 int sock; 5049 5050 if (pset->num_permitted_admin > 0) { 5051 permit_adm = 0; 5052 for (i = 0; i < pset->num_permitted_admin; i++) { 5053 perm = &pset->permitted_admin[i]; 5054 if (open_match(perm, c->path, c->host_port)) { 5055 permit_adm = 1; 5056 break; 5057 } 5058 } 5059 } 5060 if (!permit_adm) { 5061 debug_f("requested forward not permitted"); 5062 return -1; 5063 } 5064 5065 memset(&cctx, 0, sizeof(cctx)); 5066 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 5067 NULL, &cctx, NULL, NULL); 5068 if (sock == -1) 5069 channel_connect_ctx_free(&cctx); 5070 else { 5071 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 5072 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 5073 c->connect_ctx = cctx; 5074 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 5075 } 5076 return sock; 5077 } 5078 5079 /* -- X11 forwarding */ 5080 5081 /* 5082 * Creates an internet domain socket for listening for X11 connections. 5083 * Returns 0 and a suitable display number for the DISPLAY variable 5084 * stored in display_numberp , or -1 if an error occurs. 5085 */ 5086 int 5087 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 5088 int x11_use_localhost, int single_connection, 5089 u_int *display_numberp, int **chanids) 5090 { 5091 Channel *nc = NULL; 5092 int display_number, sock, port; 5093 struct addrinfo hints, *ai, *aitop; 5094 char strport[NI_MAXSERV]; 5095 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 5096 5097 if (chanids == NULL || x11_display_offset < 0 || 5098 x11_display_offset > UINT16_MAX - X11_BASE_PORT - MAX_DISPLAYS) 5099 return -1; 5100 5101 for (display_number = x11_display_offset; 5102 display_number < x11_display_offset + MAX_DISPLAYS; 5103 display_number++) { 5104 port = X11_BASE_PORT + display_number; 5105 memset(&hints, 0, sizeof(hints)); 5106 hints.ai_family = ssh->chanctxt->IPv4or6; 5107 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 5108 hints.ai_socktype = SOCK_STREAM; 5109 snprintf(strport, sizeof strport, "%d", port); 5110 if ((gaierr = getaddrinfo(NULL, strport, 5111 &hints, &aitop)) != 0) { 5112 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 5113 return -1; 5114 } 5115 for (ai = aitop; ai; ai = ai->ai_next) { 5116 if (ai->ai_family != AF_INET && 5117 ai->ai_family != AF_INET6) 5118 continue; 5119 sock = socket(ai->ai_family, ai->ai_socktype, 5120 ai->ai_protocol); 5121 if (sock == -1) { 5122 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 5123 #ifdef EPFNOSUPPORT 5124 && (errno != EPFNOSUPPORT) 5125 #endif 5126 ) { 5127 error("socket: %.100s", strerror(errno)); 5128 freeaddrinfo(aitop); 5129 return -1; 5130 } else { 5131 debug("x11_create_display_inet: Socket family %d not supported", 5132 ai->ai_family); 5133 continue; 5134 } 5135 } 5136 if (ai->ai_family == AF_INET6) 5137 sock_set_v6only(sock); 5138 if (x11_use_localhost) 5139 set_reuseaddr(sock); 5140 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5141 debug2_f("bind port %d: %.100s", port, 5142 strerror(errno)); 5143 close(sock); 5144 for (n = 0; n < num_socks; n++) 5145 close(socks[n]); 5146 num_socks = 0; 5147 break; 5148 } 5149 socks[num_socks++] = sock; 5150 if (num_socks == NUM_SOCKS) 5151 break; 5152 } 5153 freeaddrinfo(aitop); 5154 if (num_socks > 0) 5155 break; 5156 } 5157 if (display_number >= x11_display_offset + MAX_DISPLAYS) { 5158 error("Failed to allocate internet-domain X11 display socket."); 5159 return -1; 5160 } 5161 /* Start listening for connections on the socket. */ 5162 for (n = 0; n < num_socks; n++) { 5163 sock = socks[n]; 5164 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 5165 error("listen: %.100s", strerror(errno)); 5166 close(sock); 5167 return -1; 5168 } 5169 } 5170 5171 /* Allocate a channel for each socket. */ 5172 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 5173 for (n = 0; n < num_socks; n++) { 5174 sock = socks[n]; 5175 nc = channel_new(ssh, "x11-listener", 5176 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 5177 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 5178 0, "X11 inet listener", 1); 5179 nc->single_connection = single_connection; 5180 (*chanids)[n] = nc->self; 5181 } 5182 (*chanids)[n] = -1; 5183 5184 /* Return the display number for the DISPLAY environment variable. */ 5185 *display_numberp = display_number; 5186 return 0; 5187 } 5188 5189 static int 5190 connect_local_xsocket_path(const char *pathname) 5191 { 5192 int sock; 5193 struct sockaddr_un addr; 5194 5195 sock = socket(AF_UNIX, SOCK_STREAM, 0); 5196 if (sock == -1) { 5197 error("socket: %.100s", strerror(errno)); 5198 return -1; 5199 } 5200 memset(&addr, 0, sizeof(addr)); 5201 addr.sun_family = AF_UNIX; 5202 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 5203 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 5204 return sock; 5205 close(sock); 5206 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 5207 return -1; 5208 } 5209 5210 static int 5211 connect_local_xsocket(u_int dnr) 5212 { 5213 char buf[1024]; 5214 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 5215 return connect_local_xsocket_path(buf); 5216 } 5217 5218 #ifdef __APPLE__ 5219 static int 5220 is_path_to_xsocket(const char *display, char *path, size_t pathlen) 5221 { 5222 struct stat sbuf; 5223 5224 if (strlcpy(path, display, pathlen) >= pathlen) { 5225 error_f("display path too long"); 5226 return 0; 5227 } 5228 if (display[0] != '/') 5229 return 0; 5230 if (stat(path, &sbuf) == 0) { 5231 return 1; 5232 } else { 5233 char *dot = strrchr(path, '.'); 5234 if (dot != NULL) { 5235 *dot = '\0'; 5236 if (stat(path, &sbuf) == 0) { 5237 return 1; 5238 } 5239 } 5240 } 5241 return 0; 5242 } 5243 #endif 5244 5245 int 5246 x11_connect_display(struct ssh *ssh) 5247 { 5248 u_int display_number; 5249 const char *display; 5250 char buf[1024], *cp; 5251 struct addrinfo hints, *ai, *aitop; 5252 char strport[NI_MAXSERV]; 5253 int gaierr, sock = 0; 5254 5255 /* Try to open a socket for the local X server. */ 5256 display = getenv("DISPLAY"); 5257 if (!display) { 5258 error("DISPLAY not set."); 5259 return -1; 5260 } 5261 /* 5262 * Now we decode the value of the DISPLAY variable and make a 5263 * connection to the real X server. 5264 */ 5265 5266 #ifdef __APPLE__ 5267 /* Check if display is a path to a socket (as set by launchd). */ 5268 { 5269 char path[PATH_MAX]; 5270 5271 if (is_path_to_xsocket(display, path, sizeof(path))) { 5272 debug("x11_connect_display: $DISPLAY is launchd"); 5273 5274 /* Create a socket. */ 5275 sock = connect_local_xsocket_path(path); 5276 if (sock < 0) 5277 return -1; 5278 5279 /* OK, we now have a connection to the display. */ 5280 return sock; 5281 } 5282 } 5283 #endif 5284 /* 5285 * Check if it is a unix domain socket. Unix domain displays are in 5286 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 5287 */ 5288 if (strncmp(display, "unix:", 5) == 0 || 5289 display[0] == ':') { 5290 /* Connect to the unix domain socket. */ 5291 if (sscanf(strrchr(display, ':') + 1, "%u", 5292 &display_number) != 1) { 5293 error("Could not parse display number from DISPLAY: " 5294 "%.100s", display); 5295 return -1; 5296 } 5297 /* Create a socket. */ 5298 sock = connect_local_xsocket(display_number); 5299 if (sock < 0) 5300 return -1; 5301 5302 /* OK, we now have a connection to the display. */ 5303 return sock; 5304 } 5305 /* 5306 * Connect to an inet socket. The DISPLAY value is supposedly 5307 * hostname:d[.s], where hostname may also be numeric IP address. 5308 */ 5309 strlcpy(buf, display, sizeof(buf)); 5310 cp = strchr(buf, ':'); 5311 if (!cp) { 5312 error("Could not find ':' in DISPLAY: %.100s", display); 5313 return -1; 5314 } 5315 *cp = 0; 5316 /* 5317 * buf now contains the host name. But first we parse the 5318 * display number. 5319 */ 5320 if (sscanf(cp + 1, "%u", &display_number) != 1 || 5321 display_number > UINT16_MAX - X11_BASE_PORT) { 5322 error("Could not parse display number from DISPLAY: %.100s", 5323 display); 5324 return -1; 5325 } 5326 5327 /* Look up the host address */ 5328 memset(&hints, 0, sizeof(hints)); 5329 hints.ai_family = ssh->chanctxt->IPv4or6; 5330 hints.ai_socktype = SOCK_STREAM; 5331 snprintf(strport, sizeof strport, "%u", X11_BASE_PORT + display_number); 5332 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 5333 error("%.100s: unknown host. (%s)", buf, 5334 ssh_gai_strerror(gaierr)); 5335 return -1; 5336 } 5337 for (ai = aitop; ai; ai = ai->ai_next) { 5338 /* Create a socket. */ 5339 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5340 if (sock == -1) { 5341 debug2("socket: %.100s", strerror(errno)); 5342 continue; 5343 } 5344 /* Connect it to the display. */ 5345 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5346 debug2("connect %.100s port %u: %.100s", buf, 5347 X11_BASE_PORT + display_number, strerror(errno)); 5348 close(sock); 5349 continue; 5350 } 5351 /* Success */ 5352 break; 5353 } 5354 freeaddrinfo(aitop); 5355 if (!ai) { 5356 error("connect %.100s port %u: %.100s", buf, 5357 X11_BASE_PORT + display_number, strerror(errno)); 5358 return -1; 5359 } 5360 set_nodelay(sock); 5361 return sock; 5362 } 5363 5364 /* 5365 * Requests forwarding of X11 connections, generates fake authentication 5366 * data, and enables authentication spoofing. 5367 * This should be called in the client only. 5368 */ 5369 void 5370 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5371 const char *disp, const char *proto, const char *data, int want_reply) 5372 { 5373 struct ssh_channels *sc = ssh->chanctxt; 5374 u_int data_len = (u_int) strlen(data) / 2; 5375 u_int i, value; 5376 const char *cp; 5377 char *new_data; 5378 int r, screen_number; 5379 5380 if (sc->x11_saved_display == NULL) 5381 sc->x11_saved_display = xstrdup(disp); 5382 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5383 error("x11_request_forwarding_with_spoofing: different " 5384 "$DISPLAY already forwarded"); 5385 return; 5386 } 5387 5388 cp = strchr(disp, ':'); 5389 if (cp) 5390 cp = strchr(cp, '.'); 5391 if (cp) 5392 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5393 else 5394 screen_number = 0; 5395 5396 if (sc->x11_saved_proto == NULL) { 5397 /* Save protocol name. */ 5398 sc->x11_saved_proto = xstrdup(proto); 5399 5400 /* Extract real authentication data. */ 5401 sc->x11_saved_data = xmalloc(data_len); 5402 for (i = 0; i < data_len; i++) { 5403 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5404 fatal("x11_request_forwarding: bad " 5405 "authentication data: %.100s", data); 5406 } 5407 sc->x11_saved_data[i] = value; 5408 } 5409 sc->x11_saved_data_len = data_len; 5410 5411 /* Generate fake data of the same length. */ 5412 sc->x11_fake_data = xmalloc(data_len); 5413 arc4random_buf(sc->x11_fake_data, data_len); 5414 sc->x11_fake_data_len = data_len; 5415 } 5416 5417 /* Convert the fake data into hex. */ 5418 new_data = tohex(sc->x11_fake_data, data_len); 5419 5420 /* Send the request packet. */ 5421 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5422 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5423 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5424 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5425 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5426 (r = sshpkt_send(ssh)) != 0 || 5427 (r = ssh_packet_write_wait(ssh)) != 0) 5428 fatal_fr(r, "send x11-req"); 5429 free(new_data); 5430 } 5431 5432 /* 5433 * Returns whether an x11 channel was used recently (less than a second ago) 5434 */ 5435 int 5436 x11_channel_used_recently(struct ssh *ssh) { 5437 u_int i; 5438 Channel *c; 5439 time_t lastused = 0; 5440 5441 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 5442 c = ssh->chanctxt->channels[i]; 5443 if (c == NULL || c->ctype == NULL || c->lastused == 0 || 5444 strcmp(c->ctype, "x11-connection") != 0) 5445 continue; 5446 if (c->lastused > lastused) 5447 lastused = c->lastused; 5448 } 5449 return lastused != 0 && monotime() <= lastused + 1; 5450 } 5451