1 /* $NetBSD: channels.c,v 1.38 2022/10/05 22:39:36 christos Exp $ */ 2 /* $OpenBSD: channels.c,v 1.420 2022/09/19 08:49:50 djm Exp $ */ 3 4 /* 5 * Author: Tatu Ylonen <ylo@cs.hut.fi> 6 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 7 * All rights reserved 8 * This file contains functions for generic socket connection forwarding. 9 * There is also code for initiating connection forwarding for X11 connections, 10 * arbitrary tcp/ip connections, and the authentication agent connection. 11 * 12 * As far as I am concerned, the code I have written for this software 13 * can be used freely for any purpose. Any derived versions of this 14 * software must be clearly marked as such, and if the derived work is 15 * incompatible with the protocol description in the RFC file, it must be 16 * called by a name other than "ssh" or "Secure Shell". 17 * 18 * SSH2 support added by Markus Friedl. 19 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 20 * Copyright (c) 1999 Dug Song. All rights reserved. 21 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the above copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 33 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 34 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 35 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 36 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 37 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 38 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 39 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 41 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 42 */ 43 44 #include "includes.h" 45 __RCSID("$NetBSD: channels.c,v 1.38 2022/10/05 22:39:36 christos Exp $"); 46 #include <sys/param.h> 47 #include <sys/types.h> 48 #include <sys/stat.h> 49 #include <sys/ioctl.h> 50 #include <sys/un.h> 51 #include <sys/socket.h> 52 #include <sys/time.h> 53 #include <sys/queue.h> 54 55 #include <netinet/in.h> 56 #include <arpa/inet.h> 57 58 #include <errno.h> 59 #include <fcntl.h> 60 #include <limits.h> 61 #include <netdb.h> 62 #include <poll.h> 63 #include <stdarg.h> 64 #include <stdint.h> 65 #include <stdio.h> 66 #include <stdlib.h> 67 #include <string.h> 68 #include <termios.h> 69 #include <unistd.h> 70 71 #include "xmalloc.h" 72 #include "ssh.h" 73 #include "ssh2.h" 74 #include "ssherr.h" 75 #include "sshbuf.h" 76 #include "packet.h" 77 #include "log.h" 78 #include "misc.h" 79 #include "channels.h" 80 #include "compat.h" 81 #include "canohost.h" 82 #include "sshkey.h" 83 #include "authfd.h" 84 #include "pathnames.h" 85 #include "match.h" 86 87 88 static int hpn_disabled = 0; 89 static int hpn_buffer_size = 2 * 1024 * 1024; 90 91 /* XXX remove once we're satisfied there's no lurking bugs */ 92 /* #define DEBUG_CHANNEL_POLL 1 */ 93 94 /* -- agent forwarding */ 95 #define NUM_SOCKS 10 96 97 /* -- tcp forwarding */ 98 /* special-case port number meaning allow any port */ 99 #define FWD_PERMIT_ANY_PORT 0 100 101 /* special-case wildcard meaning allow any host */ 102 #define FWD_PERMIT_ANY_HOST "*" 103 104 /* -- X11 forwarding */ 105 /* Maximum number of fake X11 displays to try. */ 106 #define MAX_DISPLAYS 1000 107 108 /* Per-channel callback for pre/post IO actions */ 109 typedef void chan_fn(struct ssh *, Channel *c); 110 111 /* 112 * Data structure for storing which hosts are permitted for forward requests. 113 * The local sides of any remote forwards are stored in this array to prevent 114 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 115 * network (which might be behind a firewall). 116 */ 117 /* XXX: streamlocal wants a path instead of host:port */ 118 /* Overload host_to_connect; we could just make this match Forward */ 119 /* XXX - can we use listen_host instead of listen_path? */ 120 struct permission { 121 char *host_to_connect; /* Connect to 'host'. */ 122 int port_to_connect; /* Connect to 'port'. */ 123 char *listen_host; /* Remote side should listen address. */ 124 char *listen_path; /* Remote side should listen path. */ 125 int listen_port; /* Remote side should listen port. */ 126 Channel *downstream; /* Downstream mux*/ 127 }; 128 129 /* 130 * Stores the forwarding permission state for a single direction (local or 131 * remote). 132 */ 133 struct permission_set { 134 /* 135 * List of all local permitted host/port pairs to allow for the 136 * user. 137 */ 138 u_int num_permitted_user; 139 struct permission *permitted_user; 140 141 /* 142 * List of all permitted host/port pairs to allow for the admin. 143 */ 144 u_int num_permitted_admin; 145 struct permission *permitted_admin; 146 147 /* 148 * If this is true, all opens/listens are permitted. This is the 149 * case on the server on which we have to trust the client anyway, 150 * and the user could do anything after logging in. 151 */ 152 int all_permitted; 153 }; 154 155 /* Master structure for channels state */ 156 struct ssh_channels { 157 /* 158 * Pointer to an array containing all allocated channels. The array 159 * is dynamically extended as needed. 160 */ 161 Channel **channels; 162 163 /* 164 * Size of the channel array. All slots of the array must always be 165 * initialized (at least the type field); unused slots set to NULL 166 */ 167 u_int channels_alloc; 168 169 /* 170 * 'channel_pre*' are called just before IO to add any bits 171 * relevant to channels in the c->io_want bitmasks. 172 * 173 * 'channel_post*': perform any appropriate operations for 174 * channels which have c->io_ready events pending. 175 */ 176 chan_fn **channel_pre; 177 chan_fn **channel_post; 178 179 /* -- tcp forwarding */ 180 struct permission_set local_perms; 181 struct permission_set remote_perms; 182 183 /* -- X11 forwarding */ 184 185 /* Saved X11 local (client) display. */ 186 char *x11_saved_display; 187 188 /* Saved X11 authentication protocol name. */ 189 char *x11_saved_proto; 190 191 /* Saved X11 authentication data. This is the real data. */ 192 char *x11_saved_data; 193 u_int x11_saved_data_len; 194 195 /* Deadline after which all X11 connections are refused */ 196 u_int x11_refuse_time; 197 198 /* 199 * Fake X11 authentication data. This is what the server will be 200 * sending us; we should replace any occurrences of this by the 201 * real data. 202 */ 203 u_char *x11_fake_data; 204 u_int x11_fake_data_len; 205 206 /* AF_UNSPEC or AF_INET or AF_INET6 */ 207 int IPv4or6; 208 }; 209 210 /* helper */ 211 static void port_open_helper(struct ssh *ssh, Channel *c, const char *rtype); 212 static const char *channel_rfwd_bind_host(const char *listen_host); 213 214 /* non-blocking connect helpers */ 215 static int connect_next(struct channel_connect *); 216 static void channel_connect_ctx_free(struct channel_connect *); 217 static Channel *rdynamic_connect_prepare(struct ssh *, const char *, 218 const char *); 219 static int rdynamic_connect_finish(struct ssh *, Channel *); 220 221 /* Setup helper */ 222 static void channel_handler_init(struct ssh_channels *sc); 223 224 /* -- channel core */ 225 226 void 227 channel_init_channels(struct ssh *ssh) 228 { 229 struct ssh_channels *sc; 230 231 if ((sc = calloc(1, sizeof(*sc))) == NULL) 232 fatal_f("allocation failed"); 233 sc->channels_alloc = 10; 234 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 235 sc->IPv4or6 = AF_UNSPEC; 236 channel_handler_init(sc); 237 238 ssh->chanctxt = sc; 239 } 240 241 Channel * 242 channel_by_id(struct ssh *ssh, int id) 243 { 244 Channel *c; 245 246 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 247 logit_f("%d: bad id", id); 248 return NULL; 249 } 250 c = ssh->chanctxt->channels[id]; 251 if (c == NULL) { 252 logit_f("%d: bad id: channel free", id); 253 return NULL; 254 } 255 return c; 256 } 257 258 Channel * 259 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 260 { 261 Channel *c; 262 u_int i; 263 264 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 265 c = ssh->chanctxt->channels[i]; 266 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 267 return c; 268 } 269 return NULL; 270 } 271 272 /* 273 * Returns the channel if it is allowed to receive protocol messages. 274 * Private channels, like listening sockets, may not receive messages. 275 */ 276 Channel * 277 channel_lookup(struct ssh *ssh, int id) 278 { 279 Channel *c; 280 281 if ((c = channel_by_id(ssh, id)) == NULL) 282 return NULL; 283 284 switch (c->type) { 285 case SSH_CHANNEL_X11_OPEN: 286 case SSH_CHANNEL_LARVAL: 287 case SSH_CHANNEL_CONNECTING: 288 case SSH_CHANNEL_DYNAMIC: 289 case SSH_CHANNEL_RDYNAMIC_OPEN: 290 case SSH_CHANNEL_RDYNAMIC_FINISH: 291 case SSH_CHANNEL_OPENING: 292 case SSH_CHANNEL_OPEN: 293 case SSH_CHANNEL_ABANDONED: 294 case SSH_CHANNEL_MUX_PROXY: 295 return c; 296 } 297 logit("Non-public channel %d, type %d.", id, c->type); 298 return NULL; 299 } 300 301 /* 302 * Register filedescriptors for a channel, used when allocating a channel or 303 * when the channel consumer/producer is ready, e.g. shell exec'd 304 */ 305 static void 306 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 307 int extusage, int nonblock, int is_tty) 308 { 309 int val; 310 311 if (rfd != -1) 312 fcntl(rfd, F_SETFD, FD_CLOEXEC); 313 if (wfd != -1 && wfd != rfd) 314 fcntl(wfd, F_SETFD, FD_CLOEXEC); 315 if (efd != -1 && efd != rfd && efd != wfd) 316 fcntl(efd, F_SETFD, FD_CLOEXEC); 317 318 c->rfd = rfd; 319 c->wfd = wfd; 320 c->sock = (rfd == wfd) ? rfd : -1; 321 c->efd = efd; 322 c->extended_usage = extusage; 323 324 if ((c->isatty = is_tty) != 0) 325 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 326 327 /* enable nonblocking mode */ 328 c->restore_block = 0; 329 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 330 /* 331 * Special handling for stdio file descriptors: do not set 332 * non-blocking mode if they are TTYs. Otherwise prepare to 333 * restore their blocking state on exit to avoid interfering 334 * with other programs that follow. 335 */ 336 if (rfd != -1 && !isatty(rfd) && 337 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 338 c->restore_block |= CHANNEL_RESTORE_RFD; 339 set_nonblock(rfd); 340 } 341 if (wfd != -1 && !isatty(wfd) && 342 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 343 c->restore_block |= CHANNEL_RESTORE_WFD; 344 set_nonblock(wfd); 345 } 346 if (efd != -1 && !isatty(efd) && 347 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 348 c->restore_block |= CHANNEL_RESTORE_EFD; 349 set_nonblock(efd); 350 } 351 } else if (nonblock) { 352 if (rfd != -1) 353 set_nonblock(rfd); 354 if (wfd != -1) 355 set_nonblock(wfd); 356 if (efd != -1) 357 set_nonblock(efd); 358 } 359 } 360 361 /* 362 * Allocate a new channel object and set its type and socket. 363 */ 364 Channel * 365 channel_new(struct ssh *ssh, const char *ctype, int type, int rfd, int wfd, 366 int efd, u_int window, u_int maxpack, int extusage, const char *remote_name, 367 int nonblock) 368 { 369 struct ssh_channels *sc = ssh->chanctxt; 370 u_int i, found; 371 Channel *c; 372 int r; 373 374 /* Try to find a free slot where to put the new channel. */ 375 for (i = 0; i < sc->channels_alloc; i++) { 376 if (sc->channels[i] == NULL) { 377 /* Found a free slot. */ 378 found = i; 379 break; 380 } 381 } 382 if (i >= sc->channels_alloc) { 383 /* 384 * There are no free slots. Take last+1 slot and expand 385 * the array. 386 */ 387 found = sc->channels_alloc; 388 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 389 fatal_f("internal error: channels_alloc %d too big", 390 sc->channels_alloc); 391 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 392 sc->channels_alloc + 10, sizeof(*sc->channels)); 393 sc->channels_alloc += 10; 394 debug2("channel: expanding %d", sc->channels_alloc); 395 } 396 /* Initialize and return new channel. */ 397 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 398 if ((c->input = sshbuf_new()) == NULL || 399 (c->output = sshbuf_new()) == NULL || 400 (c->extended = sshbuf_new()) == NULL) 401 fatal_f("sshbuf_new failed"); 402 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 403 fatal_fr(r, "sshbuf_set_max_size"); 404 c->ostate = CHAN_OUTPUT_OPEN; 405 c->istate = CHAN_INPUT_OPEN; 406 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 407 c->self = found; 408 c->type = type; 409 c->ctype = __UNCONST(ctype); 410 c->local_window = window; 411 c->local_window_max = window; 412 c->local_maxpacket = maxpack; 413 c->dynamic_window = 0; 414 c->remote_id = -1; 415 c->remote_name = xstrdup(remote_name); 416 c->ctl_chan = -1; 417 c->delayed = 1; /* prevent call to channel_post handler */ 418 TAILQ_INIT(&c->status_confirms); 419 debug("channel %d: new [%s]", found, remote_name); 420 return c; 421 } 422 423 int 424 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 425 { 426 int ret, fd = *fdp; 427 428 if (fd == -1) 429 return 0; 430 431 if ((*fdp == c->rfd && (c->restore_block & CHANNEL_RESTORE_RFD) != 0) || 432 (*fdp == c->wfd && (c->restore_block & CHANNEL_RESTORE_WFD) != 0) || 433 (*fdp == c->efd && (c->restore_block & CHANNEL_RESTORE_EFD) != 0)) 434 (void)fcntl(*fdp, F_SETFL, 0); /* restore blocking */ 435 436 if (*fdp == c->rfd) { 437 c->io_want &= ~SSH_CHAN_IO_RFD; 438 c->io_ready &= ~SSH_CHAN_IO_RFD; 439 c->rfd = -1; 440 c->pfds[0] = -1; 441 } 442 if (*fdp == c->wfd) { 443 c->io_want &= ~SSH_CHAN_IO_WFD; 444 c->io_ready &= ~SSH_CHAN_IO_WFD; 445 c->wfd = -1; 446 c->pfds[1] = -1; 447 } 448 if (*fdp == c->efd) { 449 c->io_want &= ~SSH_CHAN_IO_EFD; 450 c->io_ready &= ~SSH_CHAN_IO_EFD; 451 c->efd = -1; 452 c->pfds[2] = -1; 453 } 454 if (*fdp == c->sock) { 455 c->io_want &= ~SSH_CHAN_IO_SOCK; 456 c->io_ready &= ~SSH_CHAN_IO_SOCK; 457 c->sock = -1; 458 c->pfds[3] = -1; 459 } 460 461 ret = close(fd); 462 *fdp = -1; /* probably redundant */ 463 return ret; 464 } 465 466 /* Close all channel fd/socket. */ 467 static void 468 channel_close_fds(struct ssh *ssh, Channel *c) 469 { 470 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 471 472 channel_close_fd(ssh, c, &c->sock); 473 if (rfd != sock) 474 channel_close_fd(ssh, c, &c->rfd); 475 if (wfd != sock && wfd != rfd) 476 channel_close_fd(ssh, c, &c->wfd); 477 if (efd != sock && efd != rfd && efd != wfd) 478 channel_close_fd(ssh, c, &c->efd); 479 } 480 481 static void 482 fwd_perm_clear(struct permission *perm) 483 { 484 free(perm->host_to_connect); 485 free(perm->listen_host); 486 free(perm->listen_path); 487 memset(perm, 0, sizeof(*perm)); 488 } 489 490 /* Returns an printable name for the specified forwarding permission list */ 491 static const char * 492 fwd_ident(int who, int where) 493 { 494 if (who == FORWARD_ADM) { 495 if (where == FORWARD_LOCAL) 496 return "admin local"; 497 else if (where == FORWARD_REMOTE) 498 return "admin remote"; 499 } else if (who == FORWARD_USER) { 500 if (where == FORWARD_LOCAL) 501 return "user local"; 502 else if (where == FORWARD_REMOTE) 503 return "user remote"; 504 } 505 fatal("Unknown forward permission list %d/%d", who, where); 506 } 507 508 /* Returns the forwarding permission list for the specified direction */ 509 static struct permission_set * 510 permission_set_get(struct ssh *ssh, int where) 511 { 512 struct ssh_channels *sc = ssh->chanctxt; 513 514 switch (where) { 515 case FORWARD_LOCAL: 516 return &sc->local_perms; 517 break; 518 case FORWARD_REMOTE: 519 return &sc->remote_perms; 520 break; 521 default: 522 fatal_f("invalid forwarding direction %d", where); 523 } 524 } 525 526 /* Returns pointers to the specified forwarding list and its element count */ 527 static void 528 permission_set_get_array(struct ssh *ssh, int who, int where, 529 struct permission ***permpp, u_int **npermpp) 530 { 531 struct permission_set *pset = permission_set_get(ssh, where); 532 533 switch (who) { 534 case FORWARD_USER: 535 *permpp = &pset->permitted_user; 536 *npermpp = &pset->num_permitted_user; 537 break; 538 case FORWARD_ADM: 539 *permpp = &pset->permitted_admin; 540 *npermpp = &pset->num_permitted_admin; 541 break; 542 default: 543 fatal_f("invalid forwarding client %d", who); 544 } 545 } 546 547 /* Adds an entry to the specified forwarding list */ 548 static int 549 permission_set_add(struct ssh *ssh, int who, int where, 550 const char *host_to_connect, int port_to_connect, 551 const char *listen_host, const char *listen_path, int listen_port, 552 Channel *downstream) 553 { 554 struct permission **permp; 555 u_int n, *npermp; 556 557 permission_set_get_array(ssh, who, where, &permp, &npermp); 558 559 if (*npermp >= INT_MAX) 560 fatal_f("%s overflow", fwd_ident(who, where)); 561 562 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 563 n = (*npermp)++; 564 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 565 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 566 (*permp)[n].port_to_connect = port_to_connect; 567 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 568 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 569 (*permp)[n].listen_port = listen_port; 570 (*permp)[n].downstream = downstream; 571 #undef MAYBE_DUP 572 return (int)n; 573 } 574 575 static void 576 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 577 { 578 struct ssh_channels *sc = ssh->chanctxt; 579 struct permission_set *pset = &sc->local_perms; 580 struct permission *perm; 581 int r; 582 u_int i; 583 584 for (i = 0; i < pset->num_permitted_user; i++) { 585 perm = &pset->permitted_user[i]; 586 if (perm->downstream != c) 587 continue; 588 589 /* cancel on the server, since mux client is gone */ 590 debug("channel %d: cleanup remote forward for %s:%u", 591 c->self, perm->listen_host, perm->listen_port); 592 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 593 (r = sshpkt_put_cstring(ssh, 594 "cancel-tcpip-forward")) != 0 || 595 (r = sshpkt_put_u8(ssh, 0)) != 0 || 596 (r = sshpkt_put_cstring(ssh, 597 channel_rfwd_bind_host(perm->listen_host))) != 0 || 598 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 599 (r = sshpkt_send(ssh)) != 0) { 600 fatal_fr(r, "channel %i", c->self); 601 } 602 fwd_perm_clear(perm); /* unregister */ 603 } 604 } 605 606 /* Free the channel and close its fd/socket. */ 607 void 608 channel_free(struct ssh *ssh, Channel *c) 609 { 610 struct ssh_channels *sc = ssh->chanctxt; 611 char *s; 612 u_int i, n; 613 Channel *other; 614 struct channel_confirm *cc; 615 616 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 617 if ((other = sc->channels[i]) == NULL) 618 continue; 619 n++; 620 /* detach from mux client and prepare for closing */ 621 if (c->type == SSH_CHANNEL_MUX_CLIENT && 622 other->type == SSH_CHANNEL_MUX_PROXY && 623 other->mux_ctx == c) { 624 other->mux_ctx = NULL; 625 other->type = SSH_CHANNEL_OPEN; 626 other->istate = CHAN_INPUT_CLOSED; 627 other->ostate = CHAN_OUTPUT_CLOSED; 628 } 629 } 630 debug("channel %d: free: %s, nchannels %u", c->self, 631 c->remote_name ? c->remote_name : "???", n); 632 633 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 634 mux_remove_remote_forwardings(ssh, c); 635 free(c->mux_ctx); 636 c->mux_ctx = NULL; 637 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 638 free(c->mux_ctx); 639 c->mux_ctx = NULL; 640 } 641 642 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 643 s = channel_open_message(ssh); 644 debug3("channel %d: status: %s", c->self, s); 645 free(s); 646 } 647 648 channel_close_fds(ssh, c); 649 sshbuf_free(c->input); 650 sshbuf_free(c->output); 651 sshbuf_free(c->extended); 652 c->input = c->output = c->extended = NULL; 653 free(c->remote_name); 654 c->remote_name = NULL; 655 free(c->path); 656 c->path = NULL; 657 free(c->listening_addr); 658 c->listening_addr = NULL; 659 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 660 if (cc->abandon_cb != NULL) 661 cc->abandon_cb(ssh, c, cc->ctx); 662 TAILQ_REMOVE(&c->status_confirms, cc, entry); 663 freezero(cc, sizeof(*cc)); 664 } 665 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 666 c->filter_cleanup(ssh, c->self, c->filter_ctx); 667 sc->channels[c->self] = NULL; 668 freezero(c, sizeof(*c)); 669 } 670 671 void 672 channel_free_all(struct ssh *ssh) 673 { 674 u_int i; 675 struct ssh_channels *sc = ssh->chanctxt; 676 677 for (i = 0; i < sc->channels_alloc; i++) 678 if (sc->channels[i] != NULL) 679 channel_free(ssh, sc->channels[i]); 680 681 free(sc->channels); 682 sc->channels = NULL; 683 sc->channels_alloc = 0; 684 685 free(sc->x11_saved_display); 686 sc->x11_saved_display = NULL; 687 688 free(sc->x11_saved_proto); 689 sc->x11_saved_proto = NULL; 690 691 free(sc->x11_saved_data); 692 sc->x11_saved_data = NULL; 693 sc->x11_saved_data_len = 0; 694 695 free(sc->x11_fake_data); 696 sc->x11_fake_data = NULL; 697 sc->x11_fake_data_len = 0; 698 } 699 700 /* 701 * Closes the sockets/fds of all channels. This is used to close extra file 702 * descriptors after a fork. 703 */ 704 void 705 channel_close_all(struct ssh *ssh) 706 { 707 u_int i; 708 709 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 710 if (ssh->chanctxt->channels[i] != NULL) 711 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 712 } 713 714 /* 715 * Stop listening to channels. 716 */ 717 void 718 channel_stop_listening(struct ssh *ssh) 719 { 720 u_int i; 721 Channel *c; 722 723 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 724 c = ssh->chanctxt->channels[i]; 725 if (c != NULL) { 726 switch (c->type) { 727 case SSH_CHANNEL_AUTH_SOCKET: 728 case SSH_CHANNEL_PORT_LISTENER: 729 case SSH_CHANNEL_RPORT_LISTENER: 730 case SSH_CHANNEL_X11_LISTENER: 731 case SSH_CHANNEL_UNIX_LISTENER: 732 case SSH_CHANNEL_RUNIX_LISTENER: 733 channel_close_fd(ssh, c, &c->sock); 734 channel_free(ssh, c); 735 break; 736 } 737 } 738 } 739 } 740 741 /* 742 * Returns true if no channel has too much buffered data, and false if one or 743 * more channel is overfull. 744 */ 745 int 746 channel_not_very_much_buffered_data(struct ssh *ssh) 747 { 748 u_int i; 749 u_int maxsize = ssh_packet_get_maxsize(ssh); 750 Channel *c; 751 752 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 753 c = ssh->chanctxt->channels[i]; 754 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 755 continue; 756 if (sshbuf_len(c->output) > maxsize) { 757 debug2("channel %d: big output buffer %zu > %u", 758 c->self, sshbuf_len(c->output), maxsize); 759 return 0; 760 } 761 } 762 return 1; 763 } 764 765 /* Returns true if any channel is still open. */ 766 int 767 channel_still_open(struct ssh *ssh) 768 { 769 u_int i; 770 Channel *c; 771 772 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 773 c = ssh->chanctxt->channels[i]; 774 if (c == NULL) 775 continue; 776 switch (c->type) { 777 case SSH_CHANNEL_X11_LISTENER: 778 case SSH_CHANNEL_PORT_LISTENER: 779 case SSH_CHANNEL_RPORT_LISTENER: 780 case SSH_CHANNEL_MUX_LISTENER: 781 case SSH_CHANNEL_CLOSED: 782 case SSH_CHANNEL_AUTH_SOCKET: 783 case SSH_CHANNEL_DYNAMIC: 784 case SSH_CHANNEL_RDYNAMIC_OPEN: 785 case SSH_CHANNEL_CONNECTING: 786 case SSH_CHANNEL_ZOMBIE: 787 case SSH_CHANNEL_ABANDONED: 788 case SSH_CHANNEL_UNIX_LISTENER: 789 case SSH_CHANNEL_RUNIX_LISTENER: 790 continue; 791 case SSH_CHANNEL_LARVAL: 792 continue; 793 case SSH_CHANNEL_OPENING: 794 case SSH_CHANNEL_OPEN: 795 case SSH_CHANNEL_RDYNAMIC_FINISH: 796 case SSH_CHANNEL_X11_OPEN: 797 case SSH_CHANNEL_MUX_CLIENT: 798 case SSH_CHANNEL_MUX_PROXY: 799 return 1; 800 default: 801 fatal_f("bad channel type %d", c->type); 802 /* NOTREACHED */ 803 } 804 } 805 return 0; 806 } 807 808 /* Returns the id of an open channel suitable for keepaliving */ 809 int 810 channel_find_open(struct ssh *ssh) 811 { 812 u_int i; 813 Channel *c; 814 815 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 816 c = ssh->chanctxt->channels[i]; 817 if (c == NULL || !c->have_remote_id) 818 continue; 819 switch (c->type) { 820 case SSH_CHANNEL_CLOSED: 821 case SSH_CHANNEL_DYNAMIC: 822 case SSH_CHANNEL_RDYNAMIC_OPEN: 823 case SSH_CHANNEL_RDYNAMIC_FINISH: 824 case SSH_CHANNEL_X11_LISTENER: 825 case SSH_CHANNEL_PORT_LISTENER: 826 case SSH_CHANNEL_RPORT_LISTENER: 827 case SSH_CHANNEL_MUX_LISTENER: 828 case SSH_CHANNEL_MUX_CLIENT: 829 case SSH_CHANNEL_MUX_PROXY: 830 case SSH_CHANNEL_OPENING: 831 case SSH_CHANNEL_CONNECTING: 832 case SSH_CHANNEL_ZOMBIE: 833 case SSH_CHANNEL_ABANDONED: 834 case SSH_CHANNEL_UNIX_LISTENER: 835 case SSH_CHANNEL_RUNIX_LISTENER: 836 continue; 837 case SSH_CHANNEL_LARVAL: 838 case SSH_CHANNEL_AUTH_SOCKET: 839 case SSH_CHANNEL_OPEN: 840 case SSH_CHANNEL_X11_OPEN: 841 return i; 842 default: 843 fatal_f("bad channel type %d", c->type); 844 /* NOTREACHED */ 845 } 846 } 847 return -1; 848 } 849 850 /* Returns the state of the channel's extended usage flag */ 851 const char * 852 channel_format_extended_usage(const Channel *c) 853 { 854 if (c->efd == -1) 855 return "closed"; 856 857 switch (c->extended_usage) { 858 case CHAN_EXTENDED_WRITE: 859 return "write"; 860 case CHAN_EXTENDED_READ: 861 return "read"; 862 case CHAN_EXTENDED_IGNORE: 863 return "ignore"; 864 default: 865 return "UNKNOWN"; 866 } 867 } 868 869 static char * 870 channel_format_status(const Channel *c) 871 { 872 char *ret = NULL; 873 874 xasprintf(&ret, "t%d %s%u i%u/%zu o%u/%zu e[%s]/%zu " 875 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 876 c->type, 877 c->have_remote_id ? "r" : "nr", c->remote_id, 878 c->istate, sshbuf_len(c->input), 879 c->ostate, sshbuf_len(c->output), 880 channel_format_extended_usage(c), sshbuf_len(c->extended), 881 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 882 c->io_want, c->io_ready); 883 return ret; 884 } 885 886 /* 887 * Returns a message describing the currently open forwarded connections, 888 * suitable for sending to the client. The message contains crlf pairs for 889 * newlines. 890 */ 891 char * 892 channel_open_message(struct ssh *ssh) 893 { 894 struct sshbuf *buf; 895 Channel *c; 896 u_int i; 897 int r; 898 char *cp, *ret; 899 900 if ((buf = sshbuf_new()) == NULL) 901 fatal_f("sshbuf_new"); 902 if ((r = sshbuf_putf(buf, 903 "The following connections are open:\r\n")) != 0) 904 fatal_fr(r, "sshbuf_putf"); 905 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 906 c = ssh->chanctxt->channels[i]; 907 if (c == NULL) 908 continue; 909 switch (c->type) { 910 case SSH_CHANNEL_X11_LISTENER: 911 case SSH_CHANNEL_PORT_LISTENER: 912 case SSH_CHANNEL_RPORT_LISTENER: 913 case SSH_CHANNEL_CLOSED: 914 case SSH_CHANNEL_AUTH_SOCKET: 915 case SSH_CHANNEL_ZOMBIE: 916 case SSH_CHANNEL_ABANDONED: 917 case SSH_CHANNEL_MUX_LISTENER: 918 case SSH_CHANNEL_UNIX_LISTENER: 919 case SSH_CHANNEL_RUNIX_LISTENER: 920 continue; 921 case SSH_CHANNEL_LARVAL: 922 case SSH_CHANNEL_OPENING: 923 case SSH_CHANNEL_CONNECTING: 924 case SSH_CHANNEL_DYNAMIC: 925 case SSH_CHANNEL_RDYNAMIC_OPEN: 926 case SSH_CHANNEL_RDYNAMIC_FINISH: 927 case SSH_CHANNEL_OPEN: 928 case SSH_CHANNEL_X11_OPEN: 929 case SSH_CHANNEL_MUX_PROXY: 930 case SSH_CHANNEL_MUX_CLIENT: 931 cp = channel_format_status(c); 932 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 933 c->self, c->remote_name, cp)) != 0) { 934 free(cp); 935 fatal_fr(r, "sshbuf_putf"); 936 } 937 free(cp); 938 continue; 939 default: 940 fatal_f("bad channel type %d", c->type); 941 /* NOTREACHED */ 942 } 943 } 944 if ((ret = sshbuf_dup_string(buf)) == NULL) 945 fatal_f("sshbuf_dup_string"); 946 sshbuf_free(buf); 947 return ret; 948 } 949 950 static void 951 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 952 { 953 int r; 954 955 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 956 (r = sshpkt_put_cstring(ssh, type)) != 0 || 957 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 958 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 959 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 960 fatal_r(r, "%s: channel %i: open", where, c->self); 961 } 962 } 963 964 void 965 channel_send_open(struct ssh *ssh, int id) 966 { 967 Channel *c = channel_lookup(ssh, id); 968 int r; 969 970 if (c == NULL) { 971 logit("channel_send_open: %d: bad id", id); 972 return; 973 } 974 debug2("channel %d: send open", id); 975 open_preamble(ssh, __func__, c, c->ctype); 976 if ((r = sshpkt_send(ssh)) != 0) 977 fatal_fr(r, "channel %i", c->self); 978 } 979 980 void 981 channel_request_start(struct ssh *ssh, int id, const char *service, 982 int wantconfirm) 983 { 984 Channel *c = channel_lookup(ssh, id); 985 int r; 986 987 if (c == NULL) { 988 logit_f("%d: unknown channel id", id); 989 return; 990 } 991 if (!c->have_remote_id) 992 fatal_f("channel %d: no remote id", c->self); 993 994 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 995 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 996 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 997 (r = sshpkt_put_cstring(ssh, service)) != 0 || 998 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 999 fatal_fr(r, "channel %i", c->self); 1000 } 1001 } 1002 1003 void 1004 channel_register_status_confirm(struct ssh *ssh, int id, 1005 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 1006 { 1007 struct channel_confirm *cc; 1008 Channel *c; 1009 1010 if ((c = channel_lookup(ssh, id)) == NULL) 1011 fatal_f("%d: bad id", id); 1012 1013 cc = xcalloc(1, sizeof(*cc)); 1014 cc->cb = cb; 1015 cc->abandon_cb = abandon_cb; 1016 cc->ctx = ctx; 1017 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1018 } 1019 1020 void 1021 channel_register_open_confirm(struct ssh *ssh, int id, 1022 channel_open_fn *fn, void *ctx) 1023 { 1024 Channel *c = channel_lookup(ssh, id); 1025 1026 if (c == NULL) { 1027 logit_f("%d: bad id", id); 1028 return; 1029 } 1030 c->open_confirm = fn; 1031 c->open_confirm_ctx = ctx; 1032 } 1033 1034 void 1035 channel_register_cleanup(struct ssh *ssh, int id, 1036 channel_callback_fn *fn, int do_close) 1037 { 1038 Channel *c = channel_by_id(ssh, id); 1039 1040 if (c == NULL) { 1041 logit_f("%d: bad id", id); 1042 return; 1043 } 1044 c->detach_user = fn; 1045 c->detach_close = do_close; 1046 } 1047 1048 void 1049 channel_cancel_cleanup(struct ssh *ssh, int id) 1050 { 1051 Channel *c = channel_by_id(ssh, id); 1052 1053 if (c == NULL) { 1054 logit_f("%d: bad id", id); 1055 return; 1056 } 1057 c->detach_user = NULL; 1058 c->detach_close = 0; 1059 } 1060 1061 void 1062 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1063 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1064 { 1065 Channel *c = channel_lookup(ssh, id); 1066 1067 if (c == NULL) { 1068 logit_f("%d: bad id", id); 1069 return; 1070 } 1071 c->input_filter = ifn; 1072 c->output_filter = ofn; 1073 c->filter_ctx = ctx; 1074 c->filter_cleanup = cfn; 1075 } 1076 1077 void 1078 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1079 int extusage, int nonblock, int is_tty, u_int window_max) 1080 { 1081 Channel *c = channel_lookup(ssh, id); 1082 int r; 1083 1084 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1085 fatal("channel_activate for non-larval channel %d.", id); 1086 if (!c->have_remote_id) 1087 fatal_f("channel %d: no remote id", c->self); 1088 1089 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1090 c->type = SSH_CHANNEL_OPEN; 1091 c->local_window = c->local_window_max = window_max; 1092 1093 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1094 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1095 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1096 (r = sshpkt_send(ssh)) != 0) 1097 fatal_fr(r, "channel %i", c->self); 1098 } 1099 1100 static void 1101 channel_pre_listener(struct ssh *ssh, Channel *c) 1102 { 1103 c->io_want = SSH_CHAN_IO_SOCK_R; 1104 } 1105 1106 static void 1107 channel_pre_connecting(struct ssh *ssh, Channel *c) 1108 { 1109 debug3("channel %d: waiting for connection", c->self); 1110 c->io_want = SSH_CHAN_IO_SOCK_W; 1111 } 1112 1113 static int 1114 channel_tcpwinsz(struct ssh *ssh) 1115 { 1116 u_int32_t tcpwinsz = 0; 1117 socklen_t optsz = sizeof(tcpwinsz); 1118 int ret = -1; 1119 1120 /* if we aren't on a socket return 128KB*/ 1121 if(!ssh_packet_connection_is_on_socket(ssh)) 1122 return(128*1024); 1123 ret = getsockopt(ssh_packet_get_connection_in(ssh), 1124 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz); 1125 /* return no more than SSHBUF_SIZE_MAX (currently 256MB) */ 1126 if ((ret == 0) && tcpwinsz > SSHBUF_SIZE_MAX) 1127 tcpwinsz = SSHBUF_SIZE_MAX; 1128 debug2("tcpwinsz: %d for connection: %d", tcpwinsz, 1129 ssh_packet_get_connection_in(ssh)); 1130 return(tcpwinsz); 1131 } 1132 1133 static void 1134 channel_pre_open(struct ssh *ssh, Channel *c) 1135 { 1136 c->io_want = 0; 1137 if (c->istate == CHAN_INPUT_OPEN && 1138 c->remote_window > 0 && 1139 sshbuf_len(c->input) < c->remote_window && 1140 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1141 c->io_want |= SSH_CHAN_IO_RFD; 1142 if (c->ostate == CHAN_OUTPUT_OPEN || 1143 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1144 if (sshbuf_len(c->output) > 0) { 1145 c->io_want |= SSH_CHAN_IO_WFD; 1146 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1147 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1148 debug2("channel %d: " 1149 "obuf_empty delayed efd %d/(%zu)", c->self, 1150 c->efd, sshbuf_len(c->extended)); 1151 else 1152 chan_obuf_empty(ssh, c); 1153 } 1154 } 1155 /** XXX check close conditions, too */ 1156 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1157 c->ostate == CHAN_OUTPUT_CLOSED)) { 1158 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1159 sshbuf_len(c->extended) > 0) 1160 c->io_want |= SSH_CHAN_IO_EFD_W; 1161 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1162 (c->extended_usage == CHAN_EXTENDED_READ || 1163 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1164 sshbuf_len(c->extended) < c->remote_window) 1165 c->io_want |= SSH_CHAN_IO_EFD_R; 1166 } 1167 /* XXX: What about efd? races? */ 1168 } 1169 1170 /* 1171 * This is a special state for X11 authentication spoofing. An opened X11 1172 * connection (when authentication spoofing is being done) remains in this 1173 * state until the first packet has been completely read. The authentication 1174 * data in that packet is then substituted by the real data if it matches the 1175 * fake data, and the channel is put into normal mode. 1176 * XXX All this happens at the client side. 1177 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1178 */ 1179 static int 1180 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1181 { 1182 struct ssh_channels *sc = ssh->chanctxt; 1183 u_char *ucp; 1184 u_int proto_len, data_len; 1185 1186 /* Is this being called after the refusal deadline? */ 1187 if (sc->x11_refuse_time != 0 && 1188 (u_int)monotime() >= sc->x11_refuse_time) { 1189 verbose("Rejected X11 connection after ForwardX11Timeout " 1190 "expired"); 1191 return -1; 1192 } 1193 1194 /* Check if the fixed size part of the packet is in buffer. */ 1195 if (sshbuf_len(b) < 12) 1196 return 0; 1197 1198 /* Parse the lengths of variable-length fields. */ 1199 ucp = sshbuf_mutable_ptr(b); 1200 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1201 proto_len = 256 * ucp[6] + ucp[7]; 1202 data_len = 256 * ucp[8] + ucp[9]; 1203 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1204 proto_len = ucp[6] + 256 * ucp[7]; 1205 data_len = ucp[8] + 256 * ucp[9]; 1206 } else { 1207 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1208 ucp[0]); 1209 return -1; 1210 } 1211 1212 /* Check if the whole packet is in buffer. */ 1213 if (sshbuf_len(b) < 1214 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1215 return 0; 1216 1217 /* Check if authentication protocol matches. */ 1218 if (proto_len != strlen(sc->x11_saved_proto) || 1219 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1220 debug2("X11 connection uses different authentication protocol."); 1221 return -1; 1222 } 1223 /* Check if authentication data matches our fake data. */ 1224 if (data_len != sc->x11_fake_data_len || 1225 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1226 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1227 debug2("X11 auth data does not match fake data."); 1228 return -1; 1229 } 1230 /* Check fake data length */ 1231 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1232 error("X11 fake_data_len %d != saved_data_len %d", 1233 sc->x11_fake_data_len, sc->x11_saved_data_len); 1234 return -1; 1235 } 1236 /* 1237 * Received authentication protocol and data match 1238 * our fake data. Substitute the fake data with real 1239 * data. 1240 */ 1241 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1242 sc->x11_saved_data, sc->x11_saved_data_len); 1243 return 1; 1244 } 1245 1246 static void 1247 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1248 { 1249 int ret = x11_open_helper(ssh, c->output); 1250 1251 /* c->force_drain = 1; */ 1252 1253 if (ret == 1) { 1254 c->type = SSH_CHANNEL_OPEN; 1255 channel_pre_open(ssh, c); 1256 } else if (ret == -1) { 1257 logit("X11 connection rejected because of wrong authentication."); 1258 debug2("X11 rejected %d i%d/o%d", 1259 c->self, c->istate, c->ostate); 1260 chan_read_failed(ssh, c); 1261 sshbuf_reset(c->input); 1262 chan_ibuf_empty(ssh, c); 1263 sshbuf_reset(c->output); 1264 chan_write_failed(ssh, c); 1265 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1266 } 1267 } 1268 1269 static void 1270 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1271 { 1272 c->io_want = 0; 1273 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1274 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1275 c->io_want |= SSH_CHAN_IO_RFD; 1276 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1277 /* clear buffer immediately (discard any partial packet) */ 1278 sshbuf_reset(c->input); 1279 chan_ibuf_empty(ssh, c); 1280 /* Start output drain. XXX just kill chan? */ 1281 chan_rcvd_oclose(ssh, c); 1282 } 1283 if (c->ostate == CHAN_OUTPUT_OPEN || 1284 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1285 if (sshbuf_len(c->output) > 0) 1286 c->io_want |= SSH_CHAN_IO_WFD; 1287 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1288 chan_obuf_empty(ssh, c); 1289 } 1290 } 1291 1292 /* try to decode a socks4 header */ 1293 static int 1294 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1295 { 1296 const u_char *p; 1297 char *host; 1298 u_int len, have, i, found, need; 1299 char username[256]; 1300 struct { 1301 u_int8_t version; 1302 u_int8_t command; 1303 u_int16_t dest_port; 1304 struct in_addr dest_addr; 1305 } s4_req, s4_rsp; 1306 int r; 1307 1308 debug2("channel %d: decode socks4", c->self); 1309 1310 have = sshbuf_len(input); 1311 len = sizeof(s4_req); 1312 if (have < len) 1313 return 0; 1314 p = sshbuf_ptr(input); 1315 1316 need = 1; 1317 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1318 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1319 debug2("channel %d: socks4a request", c->self); 1320 /* ... and needs an extra string (the hostname) */ 1321 need = 2; 1322 } 1323 /* Check for terminating NUL on the string(s) */ 1324 for (found = 0, i = len; i < have; i++) { 1325 if (p[i] == '\0') { 1326 found++; 1327 if (found == need) 1328 break; 1329 } 1330 if (i > 1024) { 1331 /* the peer is probably sending garbage */ 1332 debug("channel %d: decode socks4: too long", 1333 c->self); 1334 return -1; 1335 } 1336 } 1337 if (found < need) 1338 return 0; 1339 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1340 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1341 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1342 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1343 debug_r(r, "channels %d: decode socks4", c->self); 1344 return -1; 1345 } 1346 have = sshbuf_len(input); 1347 p = sshbuf_ptr(input); 1348 if (memchr(p, '\0', have) == NULL) { 1349 error("channel %d: decode socks4: unterminated user", c->self); 1350 return -1; 1351 } 1352 len = strlen(p); 1353 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1354 len++; /* trailing '\0' */ 1355 strlcpy(username, p, sizeof(username)); 1356 if ((r = sshbuf_consume(input, len)) != 0) 1357 fatal_fr(r, "channel %d: consume", c->self); 1358 free(c->path); 1359 c->path = NULL; 1360 if (need == 1) { /* SOCKS4: one string */ 1361 host = inet_ntoa(s4_req.dest_addr); 1362 c->path = xstrdup(host); 1363 } else { /* SOCKS4A: two strings */ 1364 have = sshbuf_len(input); 1365 p = sshbuf_ptr(input); 1366 if (memchr(p, '\0', have) == NULL) { 1367 error("channel %d: decode socks4a: host not nul " 1368 "terminated", c->self); 1369 return -1; 1370 } 1371 len = strlen(p); 1372 debug2("channel %d: decode socks4a: host %s/%d", 1373 c->self, p, len); 1374 len++; /* trailing '\0' */ 1375 if (len > NI_MAXHOST) { 1376 error("channel %d: hostname \"%.100s\" too long", 1377 c->self, p); 1378 return -1; 1379 } 1380 c->path = xstrdup(p); 1381 if ((r = sshbuf_consume(input, len)) != 0) 1382 fatal_fr(r, "channel %d: consume", c->self); 1383 } 1384 c->host_port = ntohs(s4_req.dest_port); 1385 1386 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1387 c->self, c->path, c->host_port, s4_req.command); 1388 1389 if (s4_req.command != 1) { 1390 debug("channel %d: cannot handle: %s cn %d", 1391 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1392 return -1; 1393 } 1394 s4_rsp.version = 0; /* vn: 0 for reply */ 1395 s4_rsp.command = 90; /* cd: req granted */ 1396 s4_rsp.dest_port = 0; /* ignored */ 1397 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1398 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1399 fatal_fr(r, "channel %d: append reply", c->self); 1400 return 1; 1401 } 1402 1403 /* try to decode a socks5 header */ 1404 #define SSH_SOCKS5_AUTHDONE 0x1000 1405 #define SSH_SOCKS5_NOAUTH 0x00 1406 #define SSH_SOCKS5_IPV4 0x01 1407 #define SSH_SOCKS5_DOMAIN 0x03 1408 #define SSH_SOCKS5_IPV6 0x04 1409 #define SSH_SOCKS5_CONNECT 0x01 1410 #define SSH_SOCKS5_SUCCESS 0x00 1411 1412 static int 1413 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1414 { 1415 /* XXX use get/put_u8 instead of trusting struct padding */ 1416 struct { 1417 u_int8_t version; 1418 u_int8_t command; 1419 u_int8_t reserved; 1420 u_int8_t atyp; 1421 } s5_req, s5_rsp; 1422 u_int16_t dest_port; 1423 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1424 const u_char *p; 1425 u_int have, need, i, found, nmethods, addrlen, af; 1426 int r; 1427 1428 debug2("channel %d: decode socks5", c->self); 1429 p = sshbuf_ptr(input); 1430 if (p[0] != 0x05) 1431 return -1; 1432 have = sshbuf_len(input); 1433 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1434 /* format: ver | nmethods | methods */ 1435 if (have < 2) 1436 return 0; 1437 nmethods = p[1]; 1438 if (have < nmethods + 2) 1439 return 0; 1440 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1441 for (found = 0, i = 2; i < nmethods + 2; i++) { 1442 if (p[i] == SSH_SOCKS5_NOAUTH) { 1443 found = 1; 1444 break; 1445 } 1446 } 1447 if (!found) { 1448 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1449 c->self); 1450 return -1; 1451 } 1452 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1453 fatal_fr(r, "channel %d: consume", c->self); 1454 /* version, method */ 1455 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1456 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1457 fatal_fr(r, "channel %d: append reply", c->self); 1458 c->flags |= SSH_SOCKS5_AUTHDONE; 1459 debug2("channel %d: socks5 auth done", c->self); 1460 return 0; /* need more */ 1461 } 1462 debug2("channel %d: socks5 post auth", c->self); 1463 if (have < sizeof(s5_req)+1) 1464 return 0; /* need more */ 1465 memcpy(&s5_req, p, sizeof(s5_req)); 1466 if (s5_req.version != 0x05 || 1467 s5_req.command != SSH_SOCKS5_CONNECT || 1468 s5_req.reserved != 0x00) { 1469 debug2("channel %d: only socks5 connect supported", c->self); 1470 return -1; 1471 } 1472 switch (s5_req.atyp){ 1473 case SSH_SOCKS5_IPV4: 1474 addrlen = 4; 1475 af = AF_INET; 1476 break; 1477 case SSH_SOCKS5_DOMAIN: 1478 addrlen = p[sizeof(s5_req)]; 1479 af = -1; 1480 break; 1481 case SSH_SOCKS5_IPV6: 1482 addrlen = 16; 1483 af = AF_INET6; 1484 break; 1485 default: 1486 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1487 return -1; 1488 } 1489 need = sizeof(s5_req) + addrlen + 2; 1490 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1491 need++; 1492 if (have < need) 1493 return 0; 1494 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1495 fatal_fr(r, "channel %d: consume", c->self); 1496 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1497 /* host string length */ 1498 if ((r = sshbuf_consume(input, 1)) != 0) 1499 fatal_fr(r, "channel %d: consume", c->self); 1500 } 1501 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1502 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1503 debug_r(r, "channel %d: parse addr/port", c->self); 1504 return -1; 1505 } 1506 dest_addr[addrlen] = '\0'; 1507 free(c->path); 1508 c->path = NULL; 1509 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1510 if (addrlen >= NI_MAXHOST) { 1511 error("channel %d: dynamic request: socks5 hostname " 1512 "\"%.100s\" too long", c->self, dest_addr); 1513 return -1; 1514 } 1515 c->path = xstrdup(dest_addr); 1516 } else { 1517 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1518 return -1; 1519 c->path = xstrdup(ntop); 1520 } 1521 c->host_port = ntohs(dest_port); 1522 1523 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1524 c->self, c->path, c->host_port, s5_req.command); 1525 1526 s5_rsp.version = 0x05; 1527 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1528 s5_rsp.reserved = 0; /* ignored */ 1529 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1530 dest_port = 0; /* ignored */ 1531 1532 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1533 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1534 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1535 fatal_fr(r, "channel %d: append reply", c->self); 1536 return 1; 1537 } 1538 1539 Channel * 1540 channel_connect_stdio_fwd(struct ssh *ssh, 1541 const char *host_to_connect, u_short port_to_connect, 1542 int in, int out, int nonblock) 1543 { 1544 Channel *c; 1545 1546 debug_f("%s:%d", host_to_connect, port_to_connect); 1547 1548 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1549 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1550 0, "stdio-forward", nonblock); 1551 1552 c->path = xstrdup(host_to_connect); 1553 c->host_port = port_to_connect; 1554 c->listening_port = 0; 1555 c->force_drain = 1; 1556 1557 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1558 port_open_helper(ssh, c, "direct-tcpip"); 1559 1560 return c; 1561 } 1562 1563 /* dynamic port forwarding */ 1564 static void 1565 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1566 { 1567 const u_char *p; 1568 u_int have; 1569 int ret; 1570 1571 c->io_want = 0; 1572 have = sshbuf_len(c->input); 1573 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1574 /* sshbuf_dump(c->input, stderr); */ 1575 /* check if the fixed size part of the packet is in buffer. */ 1576 if (have < 3) { 1577 /* need more */ 1578 c->io_want |= SSH_CHAN_IO_RFD; 1579 return; 1580 } 1581 /* try to guess the protocol */ 1582 p = sshbuf_ptr(c->input); 1583 /* XXX sshbuf_peek_u8? */ 1584 switch (p[0]) { 1585 case 0x04: 1586 ret = channel_decode_socks4(c, c->input, c->output); 1587 break; 1588 case 0x05: 1589 ret = channel_decode_socks5(c, c->input, c->output); 1590 break; 1591 default: 1592 ret = -1; 1593 break; 1594 } 1595 if (ret < 0) { 1596 chan_mark_dead(ssh, c); 1597 } else if (ret == 0) { 1598 debug2("channel %d: pre_dynamic: need more", c->self); 1599 /* need more */ 1600 c->io_want |= SSH_CHAN_IO_RFD; 1601 if (sshbuf_len(c->output)) 1602 c->io_want |= SSH_CHAN_IO_WFD; 1603 } else { 1604 /* switch to the next state */ 1605 c->type = SSH_CHANNEL_OPENING; 1606 port_open_helper(ssh, c, "direct-tcpip"); 1607 } 1608 } 1609 1610 /* simulate read-error */ 1611 static void 1612 rdynamic_close(struct ssh *ssh, Channel *c) 1613 { 1614 c->type = SSH_CHANNEL_OPEN; 1615 chan_read_failed(ssh, c); 1616 sshbuf_reset(c->input); 1617 chan_ibuf_empty(ssh, c); 1618 sshbuf_reset(c->output); 1619 chan_write_failed(ssh, c); 1620 } 1621 1622 /* reverse dynamic port forwarding */ 1623 static void 1624 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1625 { 1626 const u_char *p; 1627 u_int have, len; 1628 int r, ret; 1629 1630 have = sshbuf_len(c->output); 1631 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1632 /* sshbuf_dump(c->output, stderr); */ 1633 /* EOF received */ 1634 if (c->flags & CHAN_EOF_RCVD) { 1635 if ((r = sshbuf_consume(c->output, have)) != 0) 1636 fatal_fr(r, "channel %d: consume", c->self); 1637 rdynamic_close(ssh, c); 1638 return; 1639 } 1640 /* check if the fixed size part of the packet is in buffer. */ 1641 if (have < 3) 1642 return; 1643 /* try to guess the protocol */ 1644 p = sshbuf_ptr(c->output); 1645 switch (p[0]) { 1646 case 0x04: 1647 /* switch input/output for reverse forwarding */ 1648 ret = channel_decode_socks4(c, c->output, c->input); 1649 break; 1650 case 0x05: 1651 ret = channel_decode_socks5(c, c->output, c->input); 1652 break; 1653 default: 1654 ret = -1; 1655 break; 1656 } 1657 if (ret < 0) { 1658 rdynamic_close(ssh, c); 1659 } else if (ret == 0) { 1660 debug2("channel %d: pre_rdynamic: need more", c->self); 1661 /* send socks request to peer */ 1662 len = sshbuf_len(c->input); 1663 if (len > 0 && len < c->remote_window) { 1664 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1665 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1666 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1667 (r = sshpkt_send(ssh)) != 0) { 1668 fatal_fr(r, "channel %i: rdynamic", c->self); 1669 } 1670 if ((r = sshbuf_consume(c->input, len)) != 0) 1671 fatal_fr(r, "channel %d: consume", c->self); 1672 c->remote_window -= len; 1673 } 1674 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1675 /* the connect failed */ 1676 rdynamic_close(ssh, c); 1677 } 1678 } 1679 1680 /* This is our fake X11 server socket. */ 1681 static void 1682 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1683 { 1684 Channel *nc; 1685 struct sockaddr_storage addr; 1686 int r, newsock, oerrno, remote_port; 1687 socklen_t addrlen; 1688 char buf[16384], *remote_ipaddr; 1689 1690 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1691 return; 1692 1693 debug("X11 connection requested."); 1694 addrlen = sizeof(addr); 1695 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1696 if (c->single_connection) { 1697 oerrno = errno; 1698 debug2("single_connection: closing X11 listener."); 1699 channel_close_fd(ssh, c, &c->sock); 1700 chan_mark_dead(ssh, c); 1701 errno = oerrno; 1702 } 1703 if (newsock == -1) { 1704 if (errno != EINTR && errno != EWOULDBLOCK && 1705 errno != ECONNABORTED) 1706 error("accept: %.100s", strerror(errno)); 1707 if (errno == EMFILE || errno == ENFILE) 1708 c->notbefore = monotime() + 1; 1709 return; 1710 } 1711 set_nodelay(newsock); 1712 remote_ipaddr = get_peer_ipaddr(newsock); 1713 remote_port = get_peer_port(newsock); 1714 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1715 remote_ipaddr, remote_port); 1716 1717 nc = channel_new(ssh, "accepted x11 socket", 1718 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1719 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1720 open_preamble(ssh, __func__, nc, "x11"); 1721 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1722 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1723 fatal_fr(r, "channel %i: reply", c->self); 1724 } 1725 if ((r = sshpkt_send(ssh)) != 0) 1726 fatal_fr(r, "channel %i: send", c->self); 1727 free(remote_ipaddr); 1728 } 1729 1730 static void 1731 port_open_helper(struct ssh *ssh, Channel *c, const char *rtype) 1732 { 1733 char *local_ipaddr = get_local_ipaddr(c->sock); 1734 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1735 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1736 int remote_port = get_peer_port(c->sock); 1737 int r; 1738 1739 if (remote_port == -1) { 1740 /* Fake addr/port to appease peers that validate it (Tectia) */ 1741 free(remote_ipaddr); 1742 remote_ipaddr = xstrdup("127.0.0.1"); 1743 remote_port = 65535; 1744 } 1745 1746 free(c->remote_name); 1747 xasprintf(&c->remote_name, 1748 "%s: listening port %d for %.100s port %d, " 1749 "connect from %.200s port %d to %.100s port %d", 1750 rtype, c->listening_port, c->path, c->host_port, 1751 remote_ipaddr, remote_port, local_ipaddr, local_port); 1752 1753 open_preamble(ssh, __func__, c, rtype); 1754 if (strcmp(rtype, "direct-tcpip") == 0) { 1755 /* target host, port */ 1756 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1757 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1758 fatal_fr(r, "channel %i: reply", c->self); 1759 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1760 /* target path */ 1761 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1762 fatal_fr(r, "channel %i: reply", c->self); 1763 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1764 /* listen path */ 1765 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1766 fatal_fr(r, "channel %i: reply", c->self); 1767 } else { 1768 /* listen address, port */ 1769 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1770 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1771 fatal_fr(r, "channel %i: reply", c->self); 1772 } 1773 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1774 /* reserved for future owner/mode info */ 1775 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1776 fatal_fr(r, "channel %i: reply", c->self); 1777 } else { 1778 /* originator host and port */ 1779 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1780 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1781 fatal_fr(r, "channel %i: reply", c->self); 1782 } 1783 if ((r = sshpkt_send(ssh)) != 0) 1784 fatal_fr(r, "channel %i: send", c->self); 1785 free(remote_ipaddr); 1786 free(local_ipaddr); 1787 } 1788 1789 void 1790 channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time) 1791 { 1792 ssh->chanctxt->x11_refuse_time = refuse_time; 1793 } 1794 1795 /* 1796 * This socket is listening for connections to a forwarded TCP/IP port. 1797 */ 1798 static void 1799 channel_post_port_listener(struct ssh *ssh, Channel *c) 1800 { 1801 Channel *nc; 1802 struct sockaddr_storage addr; 1803 int newsock, nextstate; 1804 socklen_t addrlen; 1805 const char *rtype; 1806 1807 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1808 return; 1809 1810 debug("Connection to port %d forwarding to %.100s port %d requested.", 1811 c->listening_port, c->path, c->host_port); 1812 1813 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1814 nextstate = SSH_CHANNEL_OPENING; 1815 rtype = "forwarded-tcpip"; 1816 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1817 nextstate = SSH_CHANNEL_OPENING; 1818 rtype = "forwarded-streamlocal@openssh.com"; 1819 } else if (c->host_port == PORT_STREAMLOCAL) { 1820 nextstate = SSH_CHANNEL_OPENING; 1821 rtype = "direct-streamlocal@openssh.com"; 1822 } else if (c->host_port == 0) { 1823 nextstate = SSH_CHANNEL_DYNAMIC; 1824 rtype = "dynamic-tcpip"; 1825 } else { 1826 nextstate = SSH_CHANNEL_OPENING; 1827 rtype = "direct-tcpip"; 1828 } 1829 1830 addrlen = sizeof(addr); 1831 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1832 if (newsock == -1) { 1833 if (errno != EINTR && errno != EWOULDBLOCK && 1834 errno != ECONNABORTED) 1835 error("accept: %.100s", strerror(errno)); 1836 if (errno == EMFILE || errno == ENFILE) 1837 c->notbefore = monotime() + 1; 1838 return; 1839 } 1840 if (c->host_port != PORT_STREAMLOCAL) 1841 set_nodelay(newsock); 1842 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1843 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1844 nc->listening_port = c->listening_port; 1845 nc->host_port = c->host_port; 1846 if (c->path != NULL) 1847 nc->path = xstrdup(c->path); 1848 1849 if (nextstate != SSH_CHANNEL_DYNAMIC) 1850 port_open_helper(ssh, nc, rtype); 1851 } 1852 1853 /* 1854 * This is the authentication agent socket listening for connections from 1855 * clients. 1856 */ 1857 static void 1858 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1859 { 1860 Channel *nc; 1861 int r, newsock; 1862 struct sockaddr_storage addr; 1863 socklen_t addrlen; 1864 1865 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1866 return; 1867 1868 addrlen = sizeof(addr); 1869 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1870 if (newsock == -1) { 1871 error("accept from auth socket: %.100s", strerror(errno)); 1872 if (errno == EMFILE || errno == ENFILE) 1873 c->notbefore = monotime() + 1; 1874 return; 1875 } 1876 nc = channel_new(ssh, "accepted auth socket", 1877 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1878 c->local_window_max, c->local_maxpacket, 1879 0, "accepted auth socket", 1); 1880 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1881 if ((r = sshpkt_send(ssh)) != 0) 1882 fatal_fr(r, "channel %i", c->self); 1883 } 1884 1885 static void 1886 channel_post_connecting(struct ssh *ssh, Channel *c) 1887 { 1888 int err = 0, sock, isopen, r; 1889 socklen_t sz = sizeof(err); 1890 1891 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 1892 return; 1893 if (!c->have_remote_id) 1894 fatal_f("channel %d: no remote id", c->self); 1895 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1896 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1897 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 1898 err = errno; 1899 error("getsockopt SO_ERROR failed"); 1900 } 1901 if (err == 0) { 1902 debug("channel %d: connected to %s port %d", 1903 c->self, c->connect_ctx.host, c->connect_ctx.port); 1904 channel_connect_ctx_free(&c->connect_ctx); 1905 c->type = SSH_CHANNEL_OPEN; 1906 if (isopen) { 1907 /* no message necessary */ 1908 } else { 1909 if ((r = sshpkt_start(ssh, 1910 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1911 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1912 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1913 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1914 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1915 (r = sshpkt_send(ssh)) != 0) 1916 fatal_fr(r, "channel %i open confirm", c->self); 1917 } 1918 } else { 1919 debug("channel %d: connection failed: %s", 1920 c->self, strerror(err)); 1921 /* Try next address, if any */ 1922 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1923 close(c->sock); 1924 c->sock = c->rfd = c->wfd = sock; 1925 return; 1926 } 1927 /* Exhausted all addresses */ 1928 error("connect_to %.100s port %d: failed.", 1929 c->connect_ctx.host, c->connect_ctx.port); 1930 channel_connect_ctx_free(&c->connect_ctx); 1931 if (isopen) { 1932 rdynamic_close(ssh, c); 1933 } else { 1934 if ((r = sshpkt_start(ssh, 1935 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1936 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1937 (r = sshpkt_put_u32(ssh, 1938 SSH2_OPEN_CONNECT_FAILED)) != 0 || 1939 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 1940 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1941 (r = sshpkt_send(ssh)) != 0) 1942 fatal_fr(r, "channel %i: failure", c->self); 1943 chan_mark_dead(ssh, c); 1944 } 1945 } 1946 } 1947 1948 static int 1949 channel_handle_rfd(struct ssh *ssh, Channel *c) 1950 { 1951 char buf[CHAN_RBUF]; 1952 ssize_t len; 1953 int r; 1954 size_t have, avail, maxlen = CHANNEL_MAX_READ; 1955 1956 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 1957 return 1; /* Shouldn't happen */ 1958 if ((avail = sshbuf_avail(c->input)) == 0) 1959 return 1; /* Shouldn't happen */ 1960 1961 /* 1962 * For "simple" channels (i.e. not datagram or filtered), we can 1963 * read directly to the channel buffer. 1964 */ 1965 if (c->input_filter == NULL && !c->datagram) { 1966 /* Only OPEN channels have valid rwin */ 1967 if (c->type == SSH_CHANNEL_OPEN) { 1968 if ((have = sshbuf_len(c->input)) >= c->remote_window) 1969 return 1; /* shouldn't happen */ 1970 if (maxlen > c->remote_window - have) 1971 maxlen = c->remote_window - have; 1972 } 1973 if (maxlen > avail) 1974 maxlen = avail; 1975 if ((r = sshbuf_read(c->rfd, c->input, maxlen, NULL)) != 0) { 1976 if (errno == EINTR || errno == EAGAIN) 1977 return 1; 1978 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 1979 c->self, c->rfd, maxlen, ssh_err(r)); 1980 goto rfail; 1981 } 1982 return 1; 1983 } 1984 1985 len = read(c->rfd, buf, sizeof(buf)); 1986 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 1987 return 1; 1988 if (len <= 0) { 1989 debug2("channel %d: read<=0 rfd %d len %zd: %s", 1990 c->self, c->rfd, len, 1991 len == 0 ? "closed" : strerror(errno)); 1992 rfail: 1993 if (c->type != SSH_CHANNEL_OPEN) { 1994 debug2("channel %d: not open", c->self); 1995 chan_mark_dead(ssh, c); 1996 return -1; 1997 } else { 1998 chan_read_failed(ssh, c); 1999 } 2000 return -1; 2001 } 2002 if (c->input_filter != NULL) { 2003 if (c->input_filter(ssh, c, buf, len) == -1) { 2004 debug2("channel %d: filter stops", c->self); 2005 chan_read_failed(ssh, c); 2006 } 2007 } else if (c->datagram) { 2008 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2009 fatal_fr(r, "channel %i: put datagram", c->self); 2010 } 2011 return 1; 2012 } 2013 2014 static int 2015 channel_handle_wfd(struct ssh *ssh, Channel *c) 2016 { 2017 struct termios tio; 2018 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2019 size_t dlen, olen = 0; 2020 int r, len; 2021 2022 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2023 return 1; 2024 if (sshbuf_len(c->output) == 0) 2025 return 1; 2026 2027 /* Send buffered output data to the socket. */ 2028 olen = sshbuf_len(c->output); 2029 if (c->output_filter != NULL) { 2030 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2031 debug2("channel %d: filter stops", c->self); 2032 if (c->type != SSH_CHANNEL_OPEN) 2033 chan_mark_dead(ssh, c); 2034 else 2035 chan_write_failed(ssh, c); 2036 return -1; 2037 } 2038 } else if (c->datagram) { 2039 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2040 fatal_fr(r, "channel %i: get datagram", c->self); 2041 buf = data; 2042 } else { 2043 buf = data = sshbuf_mutable_ptr(c->output); 2044 dlen = sshbuf_len(c->output); 2045 } 2046 2047 if (c->datagram) { 2048 /* ignore truncated writes, datagrams might get lost */ 2049 len = write(c->wfd, buf, dlen); 2050 free(data); 2051 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2052 return 1; 2053 if (len <= 0) 2054 goto write_fail; 2055 goto out; 2056 } 2057 2058 len = write(c->wfd, buf, dlen); 2059 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2060 return 1; 2061 if (len <= 0) { 2062 write_fail: 2063 if (c->type != SSH_CHANNEL_OPEN) { 2064 debug2("channel %d: not open", c->self); 2065 chan_mark_dead(ssh, c); 2066 return -1; 2067 } else { 2068 chan_write_failed(ssh, c); 2069 } 2070 return -1; 2071 } 2072 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2073 if (tcgetattr(c->wfd, &tio) == 0 && 2074 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2075 /* 2076 * Simulate echo to reduce the impact of 2077 * traffic analysis. We need to match the 2078 * size of a SSH2_MSG_CHANNEL_DATA message 2079 * (4 byte channel id + buf) 2080 */ 2081 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2082 (r = sshpkt_send(ssh)) != 0) 2083 fatal_fr(r, "channel %i: ignore", c->self); 2084 } 2085 } 2086 if ((r = sshbuf_consume(c->output, len)) != 0) 2087 fatal_fr(r, "channel %i: consume", c->self); 2088 out: 2089 c->local_consumed += olen - sshbuf_len(c->output); 2090 2091 return 1; 2092 } 2093 2094 static int 2095 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2096 { 2097 int r; 2098 ssize_t len; 2099 2100 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2101 return 1; 2102 if (sshbuf_len(c->extended) == 0) 2103 return 1; 2104 2105 len = write(c->efd, sshbuf_ptr(c->extended), 2106 sshbuf_len(c->extended)); 2107 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2108 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2109 return 1; 2110 if (len <= 0) { 2111 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2112 channel_close_fd(ssh, c, &c->efd); 2113 } else { 2114 if ((r = sshbuf_consume(c->extended, len)) != 0) 2115 fatal_fr(r, "channel %i: consume", c->self); 2116 c->local_consumed += len; 2117 } 2118 return 1; 2119 } 2120 2121 static int 2122 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2123 { 2124 char buf[CHAN_RBUF]; 2125 int r; 2126 ssize_t len; 2127 2128 if ((c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2129 return 1; 2130 2131 len = read(c->efd, buf, sizeof(buf)); 2132 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2133 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2134 return 1; 2135 if (len <= 0) { 2136 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2137 channel_close_fd(ssh, c, &c->efd); 2138 } else if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2139 debug3("channel %d: discard efd", c->self); 2140 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2141 fatal_fr(r, "channel %i: append", c->self); 2142 return 1; 2143 } 2144 2145 static int 2146 channel_handle_efd(struct ssh *ssh, Channel *c) 2147 { 2148 if (c->efd == -1) 2149 return 1; 2150 2151 /** XXX handle drain efd, too */ 2152 2153 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2154 return channel_handle_efd_write(ssh, c); 2155 else if (c->extended_usage == CHAN_EXTENDED_READ || 2156 c->extended_usage == CHAN_EXTENDED_IGNORE) 2157 return channel_handle_efd_read(ssh, c); 2158 2159 return 1; 2160 } 2161 2162 static int 2163 channel_check_window(struct ssh *ssh, Channel *c) 2164 { 2165 int r; 2166 2167 if (c->type == SSH_CHANNEL_OPEN && 2168 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2169 ((c->local_window_max - c->local_window > 2170 c->local_maxpacket*3) || 2171 c->local_window < c->local_window_max/2) && 2172 c->local_consumed > 0) { 2173 u_int addition = 0; 2174 u_int32_t tcpwinsz = channel_tcpwinsz(ssh); 2175 /* adjust max window size if we are in a dynamic environment */ 2176 if (c->dynamic_window && (tcpwinsz > c->local_window_max)) { 2177 /* grow the window somewhat aggressively to maintain 2178 * pressure */ 2179 addition = 1.5*(tcpwinsz - c->local_window_max); 2180 c->local_window_max += addition; 2181 debug("Channel: Window growth to %d by %d bytes", c->local_window_max, addition); 2182 } 2183 if (!c->have_remote_id) 2184 fatal_f("channel %d: no remote id", c->self); 2185 if ((r = sshpkt_start(ssh, 2186 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2187 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2188 (r = sshpkt_put_u32(ssh, c->local_consumed + addition)) != 0 || 2189 (r = sshpkt_send(ssh)) != 0) { 2190 fatal_fr(r, "channel %i", c->self); 2191 } 2192 debug2("channel %d: window %d sent adjust %d", c->self, 2193 c->local_window, 2194 c->local_consumed + addition); 2195 c->local_window += c->local_consumed + addition; 2196 c->local_consumed = 0; 2197 } 2198 return 1; 2199 } 2200 2201 static void 2202 channel_post_open(struct ssh *ssh, Channel *c) 2203 { 2204 channel_handle_rfd(ssh, c); 2205 channel_handle_wfd(ssh, c); 2206 channel_handle_efd(ssh, c); 2207 channel_check_window(ssh, c); 2208 } 2209 2210 static u_int 2211 read_mux(struct ssh *ssh, Channel *c, u_int need) 2212 { 2213 char buf[CHAN_RBUF]; 2214 ssize_t len; 2215 u_int rlen; 2216 int r; 2217 2218 if (sshbuf_len(c->input) < need) { 2219 rlen = need - sshbuf_len(c->input); 2220 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2221 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2222 return sshbuf_len(c->input); 2223 if (len <= 0) { 2224 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2225 c->self, c->rfd, len); 2226 chan_read_failed(ssh, c); 2227 return 0; 2228 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2229 fatal_fr(r, "channel %i: append", c->self); 2230 } 2231 return sshbuf_len(c->input); 2232 } 2233 2234 static void 2235 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2236 { 2237 u_int need; 2238 2239 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2240 return; 2241 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2242 return; 2243 if (c->mux_pause) 2244 return; 2245 2246 /* 2247 * Don't not read past the precise end of packets to 2248 * avoid disrupting fd passing. 2249 */ 2250 if (read_mux(ssh, c, 4) < 4) /* read header */ 2251 return; 2252 /* XXX sshbuf_peek_u32 */ 2253 need = PEEK_U32(sshbuf_ptr(c->input)); 2254 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2255 if (need > CHANNEL_MUX_MAX_PACKET) { 2256 debug2("channel %d: packet too big %u > %u", 2257 c->self, CHANNEL_MUX_MAX_PACKET, need); 2258 chan_rcvd_oclose(ssh, c); 2259 return; 2260 } 2261 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2262 return; 2263 if (c->mux_rcb(ssh, c) != 0) { 2264 debug("channel %d: mux_rcb failed", c->self); 2265 chan_mark_dead(ssh, c); 2266 return; 2267 } 2268 } 2269 2270 static void 2271 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2272 { 2273 ssize_t len; 2274 int r; 2275 2276 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2277 return; 2278 if (sshbuf_len(c->output) == 0) 2279 return; 2280 2281 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2282 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2283 return; 2284 if (len <= 0) { 2285 chan_mark_dead(ssh, c); 2286 return; 2287 } 2288 if ((r = sshbuf_consume(c->output, len)) != 0) 2289 fatal_fr(r, "channel %i: consume", c->self); 2290 } 2291 2292 static void 2293 channel_post_mux_client(struct ssh *ssh, Channel *c) 2294 { 2295 channel_post_mux_client_read(ssh, c); 2296 channel_post_mux_client_write(ssh, c); 2297 } 2298 2299 static void 2300 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2301 { 2302 Channel *nc; 2303 struct sockaddr_storage addr; 2304 socklen_t addrlen; 2305 int newsock; 2306 uid_t euid; 2307 gid_t egid; 2308 2309 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2310 return; 2311 2312 debug("multiplexing control connection"); 2313 2314 /* 2315 * Accept connection on control socket 2316 */ 2317 memset(&addr, 0, sizeof(addr)); 2318 addrlen = sizeof(addr); 2319 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2320 &addrlen)) == -1) { 2321 error_f("accept: %s", strerror(errno)); 2322 if (errno == EMFILE || errno == ENFILE) 2323 c->notbefore = monotime() + 1; 2324 return; 2325 } 2326 2327 if (getpeereid(newsock, &euid, &egid) == -1) { 2328 error_f("getpeereid failed: %s", strerror(errno)); 2329 close(newsock); 2330 return; 2331 } 2332 if ((euid != 0) && (getuid() != euid)) { 2333 error("multiplex uid mismatch: peer euid %u != uid %u", 2334 (u_int)euid, (u_int)getuid()); 2335 close(newsock); 2336 return; 2337 } 2338 nc = channel_new(ssh, "multiplex client", SSH_CHANNEL_MUX_CLIENT, 2339 newsock, newsock, -1, c->local_window_max, 2340 c->local_maxpacket, 0, "mux-control", 1); 2341 nc->mux_rcb = c->mux_rcb; 2342 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2343 /* establish state */ 2344 nc->mux_rcb(ssh, nc); 2345 /* mux state transitions must not elicit protocol messages */ 2346 nc->flags |= CHAN_LOCAL; 2347 } 2348 2349 static void 2350 channel_handler_init(struct ssh_channels *sc) 2351 { 2352 chan_fn **pre, **post; 2353 2354 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2355 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2356 fatal_f("allocation failed"); 2357 2358 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2359 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2360 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2361 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2362 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2363 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2364 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2365 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2366 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2367 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2368 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2369 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2370 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2371 2372 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2373 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2374 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2375 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2376 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2377 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2378 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2379 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2380 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2381 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2382 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2383 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2384 2385 sc->channel_pre = pre; 2386 sc->channel_post = post; 2387 } 2388 2389 /* gc dead channels */ 2390 static void 2391 channel_garbage_collect(struct ssh *ssh, Channel *c) 2392 { 2393 if (c == NULL) 2394 return; 2395 if (c->detach_user != NULL) { 2396 if (!chan_is_dead(ssh, c, c->detach_close)) 2397 return; 2398 2399 debug2("channel %d: gc: notify user", c->self); 2400 c->detach_user(ssh, c->self, NULL); 2401 /* if we still have a callback */ 2402 if (c->detach_user != NULL) 2403 return; 2404 debug2("channel %d: gc: user detached", c->self); 2405 } 2406 if (!chan_is_dead(ssh, c, 1)) 2407 return; 2408 debug2("channel %d: garbage collecting", c->self); 2409 channel_free(ssh, c); 2410 } 2411 2412 enum channel_table { CHAN_PRE, CHAN_POST }; 2413 2414 static void 2415 channel_handler(struct ssh *ssh, int table, time_t *unpause_secs) 2416 { 2417 struct ssh_channels *sc = ssh->chanctxt; 2418 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2419 u_int i, oalloc; 2420 Channel *c; 2421 time_t now; 2422 2423 now = monotime(); 2424 if (unpause_secs != NULL) 2425 *unpause_secs = 0; 2426 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2427 c = sc->channels[i]; 2428 if (c == NULL) 2429 continue; 2430 /* Try to keep IO going while rekeying */ 2431 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2432 continue; 2433 if (c->delayed) { 2434 if (table == CHAN_PRE) 2435 c->delayed = 0; 2436 else 2437 continue; 2438 } 2439 if (ftab[c->type] != NULL) { 2440 /* 2441 * Run handlers that are not paused. 2442 */ 2443 if (c->notbefore <= now) 2444 (*ftab[c->type])(ssh, c); 2445 else if (unpause_secs != NULL) { 2446 /* 2447 * Collect the time that the earliest 2448 * channel comes off pause. 2449 */ 2450 debug3_f("chan %d: skip for %d more " 2451 "seconds", c->self, 2452 (int)(c->notbefore - now)); 2453 if (*unpause_secs == 0 || 2454 (c->notbefore - now) < *unpause_secs) 2455 *unpause_secs = c->notbefore - now; 2456 } 2457 } 2458 channel_garbage_collect(ssh, c); 2459 } 2460 if (unpause_secs != NULL && *unpause_secs != 0) 2461 debug3_f("first channel unpauses in %d seconds", 2462 (int)*unpause_secs); 2463 } 2464 2465 /* 2466 * Create sockets before preparing IO. 2467 * This is necessary for things that need to happen after reading 2468 * the network-input but need to be completed before IO event setup, e.g. 2469 * because they may create new channels. 2470 */ 2471 static void 2472 channel_before_prepare_io(struct ssh *ssh) 2473 { 2474 struct ssh_channels *sc = ssh->chanctxt; 2475 Channel *c; 2476 u_int i, oalloc; 2477 2478 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2479 c = sc->channels[i]; 2480 if (c == NULL) 2481 continue; 2482 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2483 channel_before_prepare_io_rdynamic(ssh, c); 2484 } 2485 } 2486 2487 static void 2488 dump_channel_poll(const char *func, const char *what, Channel *c, 2489 u_int pollfd_offset, struct pollfd *pfd) 2490 { 2491 #ifdef DEBUG_CHANNEL_POLL 2492 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2493 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2494 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2495 c->rfd, c->wfd, c->efd, c->sock, 2496 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2497 c->io_want, c->io_ready, 2498 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2499 #endif 2500 } 2501 2502 /* Prepare pollfd entries for a single channel */ 2503 static void 2504 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2505 struct pollfd *pfd, u_int npfd) 2506 { 2507 u_int ev, p = *next_pollfd; 2508 2509 if (c == NULL) 2510 return; 2511 if (p + 4 > npfd) { 2512 /* Shouldn't happen */ 2513 fatal_f("channel %d: bad pfd offset %u (max %u)", 2514 c->self, p, npfd); 2515 } 2516 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2517 /* 2518 * prepare c->rfd 2519 * 2520 * This is a special case, since c->rfd might be the same as 2521 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2522 * IO too. 2523 */ 2524 if (c->rfd != -1) { 2525 ev = 0; 2526 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2527 ev |= POLLIN; 2528 /* rfd == wfd */ 2529 if (c->wfd == c->rfd) { 2530 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2531 ev |= POLLOUT; 2532 } 2533 /* rfd == efd */ 2534 if (c->efd == c->rfd) { 2535 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2536 ev |= POLLIN; 2537 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2538 ev |= POLLOUT; 2539 } 2540 /* rfd == sock */ 2541 if (c->sock == c->rfd) { 2542 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2543 ev |= POLLIN; 2544 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2545 ev |= POLLOUT; 2546 } 2547 /* Pack a pfd entry if any event armed for this fd */ 2548 if (ev != 0) { 2549 c->pfds[0] = p; 2550 pfd[p].fd = c->rfd; 2551 pfd[p].events = ev; 2552 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2553 p++; 2554 } 2555 } 2556 /* prepare c->wfd if wanting IO and not already handled above */ 2557 if (c->wfd != -1 && c->rfd != c->wfd) { 2558 ev = 0; 2559 if ((c->io_want & SSH_CHAN_IO_WFD)) 2560 ev |= POLLOUT; 2561 /* Pack a pfd entry if any event armed for this fd */ 2562 if (ev != 0) { 2563 c->pfds[1] = p; 2564 pfd[p].fd = c->wfd; 2565 pfd[p].events = ev; 2566 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2567 p++; 2568 } 2569 } 2570 /* prepare c->efd if wanting IO and not already handled above */ 2571 if (c->efd != -1 && c->rfd != c->efd) { 2572 ev = 0; 2573 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2574 ev |= POLLIN; 2575 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2576 ev |= POLLOUT; 2577 /* Pack a pfd entry if any event armed for this fd */ 2578 if (ev != 0) { 2579 c->pfds[2] = p; 2580 pfd[p].fd = c->efd; 2581 pfd[p].events = ev; 2582 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2583 p++; 2584 } 2585 } 2586 /* prepare c->sock if wanting IO and not already handled above */ 2587 if (c->sock != -1 && c->rfd != c->sock) { 2588 ev = 0; 2589 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2590 ev |= POLLIN; 2591 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2592 ev |= POLLOUT; 2593 /* Pack a pfd entry if any event armed for this fd */ 2594 if (ev != 0) { 2595 c->pfds[3] = p; 2596 pfd[p].fd = c->sock; 2597 pfd[p].events = 0; 2598 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2599 p++; 2600 } 2601 } 2602 *next_pollfd = p; 2603 } 2604 2605 /* * Allocate/prepare poll structure */ 2606 void 2607 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2608 u_int *npfd_activep, u_int npfd_reserved, time_t *minwait_secs) 2609 { 2610 struct ssh_channels *sc = ssh->chanctxt; 2611 u_int i, oalloc, p, npfd = npfd_reserved; 2612 2613 channel_before_prepare_io(ssh); /* might create a new channel */ 2614 /* clear out I/O flags from last poll */ 2615 for (i = 0; i < sc->channels_alloc; i++) { 2616 if (sc->channels[i] == NULL) 2617 continue; 2618 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2619 } 2620 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2621 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2622 fatal_f("too many channels"); /* shouldn't happen */ 2623 npfd += sc->channels_alloc * 4; 2624 if (npfd > *npfd_allocp) { 2625 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2626 npfd, sizeof(**pfdp)); 2627 *npfd_allocp = npfd; 2628 } 2629 *npfd_activep = npfd_reserved; 2630 oalloc = sc->channels_alloc; 2631 2632 channel_handler(ssh, CHAN_PRE, minwait_secs); 2633 2634 if (oalloc != sc->channels_alloc) { 2635 /* shouldn't happen */ 2636 fatal_f("channels_alloc changed during CHAN_PRE " 2637 "(was %u, now %u)", oalloc, sc->channels_alloc); 2638 } 2639 2640 /* Prepare pollfd */ 2641 p = npfd_reserved; 2642 for (i = 0; i < sc->channels_alloc; i++) 2643 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2644 *npfd_activep = p; 2645 } 2646 2647 static void 2648 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2649 const char *what, u_int revents_mask, u_int ready) 2650 { 2651 struct pollfd *pfd = &pfds[p]; 2652 2653 if (fd == -1) 2654 return; 2655 if (p == -1 || (u_int)p >= npfd) 2656 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2657 dump_channel_poll(__func__, what, c, p, pfd); 2658 if (pfd->fd != fd) { 2659 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2660 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2661 c->rfd, c->wfd, c->efd, c->sock); 2662 } 2663 if ((pfd->revents & POLLNVAL) != 0) { 2664 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2665 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2666 } 2667 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2668 c->io_ready |= ready & c->io_want; 2669 } 2670 2671 /* 2672 * After poll, perform any appropriate operations for channels which have 2673 * events pending. 2674 */ 2675 void 2676 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2677 { 2678 struct ssh_channels *sc = ssh->chanctxt; 2679 u_int i; 2680 int p; 2681 Channel *c; 2682 2683 #ifdef DEBUG_CHANNEL_POLL 2684 for (p = 0; p < (int)npfd; p++) { 2685 if (pfd[p].revents == 0) 2686 continue; 2687 debug_f("pfd[%u].fd %d rev 0x%04x", 2688 p, pfd[p].fd, pfd[p].revents); 2689 } 2690 #endif 2691 2692 /* Convert pollfd into c->io_ready */ 2693 for (i = 0; i < sc->channels_alloc; i++) { 2694 c = sc->channels[i]; 2695 if (c == NULL) 2696 continue; 2697 /* if rfd is shared with efd/sock then wfd should be too */ 2698 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2699 (c->rfd == c->efd || c->rfd == c->sock)) { 2700 /* Shouldn't happen */ 2701 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2702 c->self, c->rfd, c->wfd, c->efd, c->sock); 2703 } 2704 c->io_ready = 0; 2705 /* rfd, potentially shared with wfd, efd and sock */ 2706 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2707 fd_ready(c, p, pfd, npfd, c->rfd, 2708 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2709 if (c->rfd == c->wfd) { 2710 fd_ready(c, p, pfd, npfd, c->wfd, 2711 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2712 } 2713 if (c->rfd == c->efd) { 2714 fd_ready(c, p, pfd, npfd, c->efd, 2715 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2716 fd_ready(c, p, pfd, npfd, c->efd, 2717 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2718 } 2719 if (c->rfd == c->sock) { 2720 fd_ready(c, p, pfd, npfd, c->sock, 2721 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2722 fd_ready(c, p, pfd, npfd, c->sock, 2723 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2724 } 2725 dump_channel_poll(__func__, "rfd", c, p, pfd); 2726 } 2727 /* wfd */ 2728 if (c->wfd != -1 && c->wfd != c->rfd && 2729 (p = c->pfds[1]) != -1) { 2730 fd_ready(c, p, pfd, npfd, c->wfd, 2731 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2732 dump_channel_poll(__func__, "wfd", c, p, pfd); 2733 } 2734 /* efd */ 2735 if (c->efd != -1 && c->efd != c->rfd && 2736 (p = c->pfds[2]) != -1) { 2737 fd_ready(c, p, pfd, npfd, c->efd, 2738 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2739 fd_ready(c, p, pfd, npfd, c->efd, 2740 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2741 dump_channel_poll(__func__, "efd", c, p, pfd); 2742 } 2743 /* sock */ 2744 if (c->sock != -1 && c->sock != c->rfd && 2745 (p = c->pfds[3]) != -1) { 2746 fd_ready(c, p, pfd, npfd, c->sock, 2747 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2748 fd_ready(c, p, pfd, npfd, c->sock, 2749 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2750 dump_channel_poll(__func__, "sock", c, p, pfd); 2751 } 2752 } 2753 channel_handler(ssh, CHAN_POST, NULL); 2754 } 2755 2756 /* 2757 * Enqueue data for channels with open or draining c->input. 2758 */ 2759 static void 2760 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2761 { 2762 size_t len, plen; 2763 const u_char *pkt; 2764 int r; 2765 2766 if ((len = sshbuf_len(c->input)) == 0) { 2767 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2768 /* 2769 * input-buffer is empty and read-socket shutdown: 2770 * tell peer, that we will not send more data: 2771 * send IEOF. 2772 * hack for extended data: delay EOF if EFD still 2773 * in use. 2774 */ 2775 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2776 debug2("channel %d: " 2777 "ibuf_empty delayed efd %d/(%zu)", 2778 c->self, c->efd, sshbuf_len(c->extended)); 2779 else 2780 chan_ibuf_empty(ssh, c); 2781 } 2782 return; 2783 } 2784 2785 if (!c->have_remote_id) 2786 fatal_f("channel %d: no remote id", c->self); 2787 2788 if (c->datagram) { 2789 /* Check datagram will fit; drop if not */ 2790 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2791 fatal_fr(r, "channel %i: get datagram", c->self); 2792 /* 2793 * XXX this does tail-drop on the datagram queue which is 2794 * usually suboptimal compared to head-drop. Better to have 2795 * backpressure at read time? (i.e. read + discard) 2796 */ 2797 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2798 debug("channel %d: datagram too big", c->self); 2799 return; 2800 } 2801 /* Enqueue it */ 2802 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2803 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2804 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2805 (r = sshpkt_send(ssh)) != 0) 2806 fatal_fr(r, "channel %i: send datagram", c->self); 2807 c->remote_window -= plen; 2808 return; 2809 } 2810 2811 /* Enqueue packet for buffered data. */ 2812 if (len > c->remote_window) 2813 len = c->remote_window; 2814 if (len > c->remote_maxpacket) 2815 len = c->remote_maxpacket; 2816 if (len == 0) 2817 return; 2818 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2819 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2820 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2821 (r = sshpkt_send(ssh)) != 0) 2822 fatal_fr(r, "channel %i: send data", c->self); 2823 if ((r = sshbuf_consume(c->input, len)) != 0) 2824 fatal_fr(r, "channel %i: consume", c->self); 2825 c->remote_window -= len; 2826 } 2827 2828 /* 2829 * Enqueue data for channels with open c->extended in read mode. 2830 */ 2831 static void 2832 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2833 { 2834 size_t len; 2835 int r; 2836 2837 if ((len = sshbuf_len(c->extended)) == 0) 2838 return; 2839 2840 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2841 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2842 if (len > c->remote_window) 2843 len = c->remote_window; 2844 if (len > c->remote_maxpacket) 2845 len = c->remote_maxpacket; 2846 if (len == 0) 2847 return; 2848 if (!c->have_remote_id) 2849 fatal_f("channel %d: no remote id", c->self); 2850 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2851 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2852 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2853 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2854 (r = sshpkt_send(ssh)) != 0) 2855 fatal_fr(r, "channel %i: data", c->self); 2856 if ((r = sshbuf_consume(c->extended, len)) != 0) 2857 fatal_fr(r, "channel %i: consume", c->self); 2858 c->remote_window -= len; 2859 debug2("channel %d: sent ext data %zu", c->self, len); 2860 } 2861 2862 /* If there is data to send to the connection, enqueue some of it now. */ 2863 void 2864 channel_output_poll(struct ssh *ssh) 2865 { 2866 struct ssh_channels *sc = ssh->chanctxt; 2867 Channel *c; 2868 u_int i; 2869 2870 for (i = 0; i < sc->channels_alloc; i++) { 2871 c = sc->channels[i]; 2872 if (c == NULL) 2873 continue; 2874 2875 /* 2876 * We are only interested in channels that can have buffered 2877 * incoming data. 2878 */ 2879 if (c->type != SSH_CHANNEL_OPEN) 2880 continue; 2881 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2882 /* XXX is this true? */ 2883 debug3("channel %d: will not send data after close", 2884 c->self); 2885 continue; 2886 } 2887 2888 /* Get the amount of buffered data for this channel. */ 2889 if (c->istate == CHAN_INPUT_OPEN || 2890 c->istate == CHAN_INPUT_WAIT_DRAIN) 2891 channel_output_poll_input_open(ssh, c); 2892 /* Send extended data, i.e. stderr */ 2893 if (!(c->flags & CHAN_EOF_SENT) && 2894 c->extended_usage == CHAN_EXTENDED_READ) 2895 channel_output_poll_extended_read(ssh, c); 2896 } 2897 } 2898 2899 /* -- mux proxy support */ 2900 2901 /* 2902 * When multiplexing channel messages for mux clients we have to deal 2903 * with downstream messages from the mux client and upstream messages 2904 * from the ssh server: 2905 * 1) Handling downstream messages is straightforward and happens 2906 * in channel_proxy_downstream(): 2907 * - We forward all messages (mostly) unmodified to the server. 2908 * - However, in order to route messages from upstream to the correct 2909 * downstream client, we have to replace the channel IDs used by the 2910 * mux clients with a unique channel ID because the mux clients might 2911 * use conflicting channel IDs. 2912 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 2913 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 2914 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 2915 * with the newly allocated channel ID. 2916 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 2917 * channels and processed by channel_proxy_upstream(). The local channel ID 2918 * is then translated back to the original mux client ID. 2919 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 2920 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 2921 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 2922 * downstream mux client are removed. 2923 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 2924 * requires more work, because they are not addressed to a specific 2925 * channel. E.g. client_request_forwarded_tcpip() needs to figure 2926 * out whether the request is addressed to the local client or a 2927 * specific downstream client based on the listen-address/port. 2928 * 6) Agent and X11-Forwarding have a similar problem and are currently 2929 * not supported as the matching session/channel cannot be identified 2930 * easily. 2931 */ 2932 2933 /* 2934 * receive packets from downstream mux clients: 2935 * channel callback fired on read from mux client, creates 2936 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 2937 * on channel creation. 2938 */ 2939 int 2940 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 2941 { 2942 Channel *c = NULL; 2943 struct sshbuf *original = NULL, *modified = NULL; 2944 const u_char *cp; 2945 char *ctype = NULL, *listen_host = NULL; 2946 u_char type; 2947 size_t have; 2948 int ret = -1, r; 2949 u_int id, remote_id, listen_port; 2950 2951 /* sshbuf_dump(downstream->input, stderr); */ 2952 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 2953 != 0) { 2954 error_fr(r, "parse"); 2955 return -1; 2956 } 2957 if (have < 2) { 2958 error_f("short message"); 2959 return -1; 2960 } 2961 type = cp[1]; 2962 /* skip padlen + type */ 2963 cp += 2; 2964 have -= 2; 2965 if (ssh_packet_log_type(type)) 2966 debug3_f("channel %u: down->up: type %u", 2967 downstream->self, type); 2968 2969 switch (type) { 2970 case SSH2_MSG_CHANNEL_OPEN: 2971 if ((original = sshbuf_from(cp, have)) == NULL || 2972 (modified = sshbuf_new()) == NULL) { 2973 error_f("alloc"); 2974 goto out; 2975 } 2976 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 2977 (r = sshbuf_get_u32(original, &id)) != 0) { 2978 error_fr(r, "parse"); 2979 goto out; 2980 } 2981 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2982 -1, -1, -1, 0, 0, 0, ctype, 1); 2983 c->mux_ctx = downstream; /* point to mux client */ 2984 c->mux_downstream_id = id; /* original downstream id */ 2985 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 2986 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2987 (r = sshbuf_putb(modified, original)) != 0) { 2988 error_fr(r, "compose"); 2989 channel_free(ssh, c); 2990 goto out; 2991 } 2992 break; 2993 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2994 /* 2995 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 2996 * need to parse 'remote_id' instead of 'ctype'. 2997 */ 2998 if ((original = sshbuf_from(cp, have)) == NULL || 2999 (modified = sshbuf_new()) == NULL) { 3000 error_f("alloc"); 3001 goto out; 3002 } 3003 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 3004 (r = sshbuf_get_u32(original, &id)) != 0) { 3005 error_fr(r, "parse"); 3006 goto out; 3007 } 3008 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 3009 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 3010 c->mux_ctx = downstream; /* point to mux client */ 3011 c->mux_downstream_id = id; 3012 c->remote_id = remote_id; 3013 c->have_remote_id = 1; 3014 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 3015 (r = sshbuf_put_u32(modified, c->self)) != 0 || 3016 (r = sshbuf_putb(modified, original)) != 0) { 3017 error_fr(r, "compose"); 3018 channel_free(ssh, c); 3019 goto out; 3020 } 3021 break; 3022 case SSH2_MSG_GLOBAL_REQUEST: 3023 if ((original = sshbuf_from(cp, have)) == NULL) { 3024 error_f("alloc"); 3025 goto out; 3026 } 3027 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 3028 error_fr(r, "parse"); 3029 goto out; 3030 } 3031 if (strcmp(ctype, "tcpip-forward") != 0) { 3032 error_f("unsupported request %s", ctype); 3033 goto out; 3034 } 3035 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 3036 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 3037 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 3038 error_fr(r, "parse"); 3039 goto out; 3040 } 3041 if (listen_port > 65535) { 3042 error_f("tcpip-forward for %s: bad port %u", 3043 listen_host, listen_port); 3044 goto out; 3045 } 3046 /* Record that connection to this host/port is permitted. */ 3047 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 3048 listen_host, NULL, (int)listen_port, downstream); 3049 listen_host = NULL; 3050 break; 3051 case SSH2_MSG_CHANNEL_CLOSE: 3052 if (have < 4) 3053 break; 3054 remote_id = PEEK_U32(cp); 3055 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3056 if (c->flags & CHAN_CLOSE_RCVD) 3057 channel_free(ssh, c); 3058 else 3059 c->flags |= CHAN_CLOSE_SENT; 3060 } 3061 break; 3062 } 3063 if (modified) { 3064 if ((r = sshpkt_start(ssh, type)) != 0 || 3065 (r = sshpkt_putb(ssh, modified)) != 0 || 3066 (r = sshpkt_send(ssh)) != 0) { 3067 error_fr(r, "send"); 3068 goto out; 3069 } 3070 } else { 3071 if ((r = sshpkt_start(ssh, type)) != 0 || 3072 (r = sshpkt_put(ssh, cp, have)) != 0 || 3073 (r = sshpkt_send(ssh)) != 0) { 3074 error_fr(r, "send"); 3075 goto out; 3076 } 3077 } 3078 ret = 0; 3079 out: 3080 free(ctype); 3081 free(listen_host); 3082 sshbuf_free(original); 3083 sshbuf_free(modified); 3084 return ret; 3085 } 3086 3087 /* 3088 * receive packets from upstream server and de-multiplex packets 3089 * to correct downstream: 3090 * implemented as a helper for channel input handlers, 3091 * replaces local (proxy) channel ID with downstream channel ID. 3092 */ 3093 int 3094 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3095 { 3096 struct sshbuf *b = NULL; 3097 Channel *downstream; 3098 const u_char *cp = NULL; 3099 size_t len; 3100 int r; 3101 3102 /* 3103 * When receiving packets from the peer we need to check whether we 3104 * need to forward the packets to the mux client. In this case we 3105 * restore the original channel id and keep track of CLOSE messages, 3106 * so we can cleanup the channel. 3107 */ 3108 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3109 return 0; 3110 if ((downstream = c->mux_ctx) == NULL) 3111 return 0; 3112 switch (type) { 3113 case SSH2_MSG_CHANNEL_CLOSE: 3114 case SSH2_MSG_CHANNEL_DATA: 3115 case SSH2_MSG_CHANNEL_EOF: 3116 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3117 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3118 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3119 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3120 case SSH2_MSG_CHANNEL_SUCCESS: 3121 case SSH2_MSG_CHANNEL_FAILURE: 3122 case SSH2_MSG_CHANNEL_REQUEST: 3123 break; 3124 default: 3125 debug2_f("channel %u: unsupported type %u", c->self, type); 3126 return 0; 3127 } 3128 if ((b = sshbuf_new()) == NULL) { 3129 error_f("alloc reply"); 3130 goto out; 3131 } 3132 /* get remaining payload (after id) */ 3133 cp = sshpkt_ptr(ssh, &len); 3134 if (cp == NULL) { 3135 error_f("no packet"); 3136 goto out; 3137 } 3138 /* translate id and send to muxclient */ 3139 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3140 (r = sshbuf_put_u8(b, type)) != 0 || 3141 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3142 (r = sshbuf_put(b, cp, len)) != 0 || 3143 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3144 error_fr(r, "compose muxclient"); 3145 goto out; 3146 } 3147 /* sshbuf_dump(b, stderr); */ 3148 if (ssh_packet_log_type(type)) 3149 debug3_f("channel %u: up->down: type %u", c->self, type); 3150 out: 3151 /* update state */ 3152 switch (type) { 3153 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3154 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3155 if (cp && len > 4) { 3156 c->remote_id = PEEK_U32(cp); 3157 c->have_remote_id = 1; 3158 } 3159 break; 3160 case SSH2_MSG_CHANNEL_CLOSE: 3161 if (c->flags & CHAN_CLOSE_SENT) 3162 channel_free(ssh, c); 3163 else 3164 c->flags |= CHAN_CLOSE_RCVD; 3165 break; 3166 } 3167 sshbuf_free(b); 3168 return 1; 3169 } 3170 3171 /* -- protocol input */ 3172 3173 /* Parse a channel ID from the current packet */ 3174 static int 3175 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3176 { 3177 u_int32_t id; 3178 int r; 3179 3180 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3181 error_r(r, "%s: parse id", where); 3182 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3183 } 3184 if (id > INT_MAX) { 3185 error_r(r, "%s: bad channel id %u", where, id); 3186 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3187 } 3188 return (int)id; 3189 } 3190 3191 /* Lookup a channel from an ID in the current packet */ 3192 static Channel * 3193 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3194 { 3195 int id = channel_parse_id(ssh, where, what); 3196 Channel *c; 3197 3198 if ((c = channel_lookup(ssh, id)) == NULL) { 3199 ssh_packet_disconnect(ssh, 3200 "%s packet referred to nonexistent channel %d", what, id); 3201 } 3202 return c; 3203 } 3204 3205 int 3206 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3207 { 3208 const u_char *data; 3209 size_t data_len, win_len; 3210 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3211 int r; 3212 3213 if (channel_proxy_upstream(c, type, seq, ssh)) 3214 return 0; 3215 3216 /* Ignore any data for non-open channels (might happen on close) */ 3217 if (c->type != SSH_CHANNEL_OPEN && 3218 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3219 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3220 c->type != SSH_CHANNEL_X11_OPEN) 3221 return 0; 3222 3223 /* Get the data. */ 3224 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3225 (r = sshpkt_get_end(ssh)) != 0) 3226 fatal_fr(r, "channel %i: get data", c->self); 3227 3228 win_len = data_len; 3229 if (c->datagram) 3230 win_len += 4; /* string length header */ 3231 3232 /* 3233 * The sending side reduces its window as it sends data, so we 3234 * must 'fake' consumption of the data in order to ensure that window 3235 * updates are sent back. Otherwise the connection might deadlock. 3236 */ 3237 if (c->ostate != CHAN_OUTPUT_OPEN) { 3238 c->local_window -= win_len; 3239 c->local_consumed += win_len; 3240 return 0; 3241 } 3242 3243 if (win_len > c->local_maxpacket) { 3244 logit("channel %d: rcvd big packet %zu, maxpack %u", 3245 c->self, win_len, c->local_maxpacket); 3246 return 0; 3247 } 3248 if (win_len > c->local_window) { 3249 logit("channel %d: rcvd too much data %zu, win %u", 3250 c->self, win_len, c->local_window); 3251 return 0; 3252 } 3253 c->local_window -= win_len; 3254 3255 if (c->datagram) { 3256 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3257 fatal_fr(r, "channel %i: append datagram", c->self); 3258 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3259 fatal_fr(r, "channel %i: append data", c->self); 3260 3261 return 0; 3262 } 3263 3264 int 3265 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3266 { 3267 const u_char *data; 3268 size_t data_len; 3269 u_int32_t tcode; 3270 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3271 int r; 3272 3273 if (channel_proxy_upstream(c, type, seq, ssh)) 3274 return 0; 3275 if (c->type != SSH_CHANNEL_OPEN) { 3276 logit("channel %d: ext data for non open", c->self); 3277 return 0; 3278 } 3279 if (c->flags & CHAN_EOF_RCVD) { 3280 if (ssh->compat & SSH_BUG_EXTEOF) 3281 debug("channel %d: accepting ext data after eof", 3282 c->self); 3283 else 3284 ssh_packet_disconnect(ssh, "Received extended_data " 3285 "after EOF on channel %d.", c->self); 3286 } 3287 3288 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3289 error_fr(r, "parse tcode"); 3290 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3291 } 3292 if (c->efd == -1 || 3293 c->extended_usage != CHAN_EXTENDED_WRITE || 3294 tcode != SSH2_EXTENDED_DATA_STDERR) { 3295 logit("channel %d: bad ext data", c->self); 3296 return 0; 3297 } 3298 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3299 (r = sshpkt_get_end(ssh)) != 0) { 3300 error_fr(r, "parse data"); 3301 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3302 } 3303 3304 if (data_len > c->local_window) { 3305 logit("channel %d: rcvd too much extended_data %zu, win %u", 3306 c->self, data_len, c->local_window); 3307 return 0; 3308 } 3309 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3310 /* XXX sshpkt_getb? */ 3311 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3312 error_fr(r, "append"); 3313 c->local_window -= data_len; 3314 return 0; 3315 } 3316 3317 int 3318 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3319 { 3320 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3321 int r; 3322 3323 if ((r = sshpkt_get_end(ssh)) != 0) { 3324 error_fr(r, "parse data"); 3325 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3326 } 3327 3328 if (channel_proxy_upstream(c, type, seq, ssh)) 3329 return 0; 3330 chan_rcvd_ieof(ssh, c); 3331 3332 /* XXX force input close */ 3333 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3334 debug("channel %d: FORCE input drain", c->self); 3335 c->istate = CHAN_INPUT_WAIT_DRAIN; 3336 if (sshbuf_len(c->input) == 0) 3337 chan_ibuf_empty(ssh, c); 3338 } 3339 return 0; 3340 } 3341 3342 int 3343 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3344 { 3345 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3346 int r; 3347 3348 if (channel_proxy_upstream(c, type, seq, ssh)) 3349 return 0; 3350 if ((r = sshpkt_get_end(ssh)) != 0) { 3351 error_fr(r, "parse data"); 3352 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3353 } 3354 chan_rcvd_oclose(ssh, c); 3355 return 0; 3356 } 3357 3358 int 3359 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3360 { 3361 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3362 u_int32_t remote_window, remote_maxpacket; 3363 int r; 3364 3365 if (channel_proxy_upstream(c, type, seq, ssh)) 3366 return 0; 3367 if (c->type != SSH_CHANNEL_OPENING) 3368 ssh_packet_disconnect(ssh, "Received open confirmation for " 3369 "non-opening channel %d.", c->self); 3370 /* 3371 * Record the remote channel number and mark that the channel 3372 * is now open. 3373 */ 3374 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3375 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3376 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3377 (r = sshpkt_get_end(ssh)) != 0) { 3378 error_fr(r, "window/maxpacket"); 3379 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3380 } 3381 3382 c->have_remote_id = 1; 3383 c->remote_window = remote_window; 3384 c->remote_maxpacket = remote_maxpacket; 3385 c->type = SSH_CHANNEL_OPEN; 3386 if (c->open_confirm) { 3387 debug2_f("channel %d: callback start", c->self); 3388 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3389 debug2_f("channel %d: callback done", c->self); 3390 } 3391 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3392 c->remote_window, c->remote_maxpacket); 3393 return 0; 3394 } 3395 3396 static const char * 3397 reason2txt(int reason) 3398 { 3399 switch (reason) { 3400 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3401 return "administratively prohibited"; 3402 case SSH2_OPEN_CONNECT_FAILED: 3403 return "connect failed"; 3404 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3405 return "unknown channel type"; 3406 case SSH2_OPEN_RESOURCE_SHORTAGE: 3407 return "resource shortage"; 3408 } 3409 return "unknown reason"; 3410 } 3411 3412 int 3413 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3414 { 3415 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3416 u_int32_t reason; 3417 char *msg = NULL; 3418 int r; 3419 3420 if (channel_proxy_upstream(c, type, seq, ssh)) 3421 return 0; 3422 if (c->type != SSH_CHANNEL_OPENING) 3423 ssh_packet_disconnect(ssh, "Received open failure for " 3424 "non-opening channel %d.", c->self); 3425 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3426 error_fr(r, "parse reason"); 3427 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3428 } 3429 /* skip language */ 3430 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3431 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3432 (r = sshpkt_get_end(ssh)) != 0) { 3433 error_fr(r, "parse msg/lang"); 3434 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3435 } 3436 logit("channel %d: open failed: %s%s%s", c->self, 3437 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3438 free(msg); 3439 if (c->open_confirm) { 3440 debug2_f("channel %d: callback start", c->self); 3441 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3442 debug2_f("channel %d: callback done", c->self); 3443 } 3444 /* Schedule the channel for cleanup/deletion. */ 3445 chan_mark_dead(ssh, c); 3446 return 0; 3447 } 3448 3449 int 3450 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3451 { 3452 int id = channel_parse_id(ssh, __func__, "window adjust"); 3453 Channel *c; 3454 u_int32_t adjust; 3455 u_int new_rwin; 3456 int r; 3457 3458 if ((c = channel_lookup(ssh, id)) == NULL) { 3459 logit("Received window adjust for non-open channel %d.", id); 3460 return 0; 3461 } 3462 3463 if (channel_proxy_upstream(c, type, seq, ssh)) 3464 return 0; 3465 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3466 (r = sshpkt_get_end(ssh)) != 0) { 3467 error_fr(r, "parse adjust"); 3468 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3469 } 3470 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3471 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3472 fatal("channel %d: adjust %u overflows remote window %u", 3473 c->self, adjust, c->remote_window); 3474 } 3475 c->remote_window = new_rwin; 3476 return 0; 3477 } 3478 3479 int 3480 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3481 { 3482 int id = channel_parse_id(ssh, __func__, "status confirm"); 3483 Channel *c; 3484 struct channel_confirm *cc; 3485 3486 /* Reset keepalive timeout */ 3487 ssh_packet_set_alive_timeouts(ssh, 0); 3488 3489 debug2_f("type %d id %d", type, id); 3490 3491 if ((c = channel_lookup(ssh, id)) == NULL) { 3492 logit_f("%d: unknown", id); 3493 return 0; 3494 } 3495 if (channel_proxy_upstream(c, type, seq, ssh)) 3496 return 0; 3497 if (sshpkt_get_end(ssh) != 0) 3498 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3499 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3500 return 0; 3501 cc->cb(ssh, type, c, cc->ctx); 3502 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3503 freezero(cc, sizeof(*cc)); 3504 return 0; 3505 } 3506 3507 /* -- tcp forwarding */ 3508 3509 void 3510 channel_set_af(struct ssh *ssh, int af) 3511 { 3512 ssh->chanctxt->IPv4or6 = af; 3513 } 3514 3515 void 3516 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size) 3517 { 3518 hpn_disabled = external_hpn_disabled; 3519 hpn_buffer_size = external_hpn_buffer_size; 3520 debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size); 3521 } 3522 3523 /* 3524 * Determine whether or not a port forward listens to loopback, the 3525 * specified address or wildcard. On the client, a specified bind 3526 * address will always override gateway_ports. On the server, a 3527 * gateway_ports of 1 (``yes'') will override the client's specification 3528 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3529 * will bind to whatever address the client asked for. 3530 * 3531 * Special-case listen_addrs are: 3532 * 3533 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3534 * "" (empty string), "*" -> wildcard v4/v6 3535 * "localhost" -> loopback v4/v6 3536 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3537 */ 3538 static const char * 3539 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3540 int is_client, struct ForwardOptions *fwd_opts) 3541 { 3542 const char *addr = NULL; 3543 int wildcard = 0; 3544 3545 if (listen_addr == NULL) { 3546 /* No address specified: default to gateway_ports setting */ 3547 if (fwd_opts->gateway_ports) 3548 wildcard = 1; 3549 } else if (fwd_opts->gateway_ports || is_client) { 3550 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3551 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3552 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3553 (!is_client && fwd_opts->gateway_ports == 1)) { 3554 wildcard = 1; 3555 /* 3556 * Notify client if they requested a specific listen 3557 * address and it was overridden. 3558 */ 3559 if (*listen_addr != '\0' && 3560 strcmp(listen_addr, "0.0.0.0") != 0 && 3561 strcmp(listen_addr, "*") != 0) { 3562 ssh_packet_send_debug(ssh, 3563 "Forwarding listen address " 3564 "\"%s\" overridden by server " 3565 "GatewayPorts", listen_addr); 3566 } 3567 } else if (strcmp(listen_addr, "localhost") != 0 || 3568 strcmp(listen_addr, "127.0.0.1") == 0 || 3569 strcmp(listen_addr, "::1") == 0) { 3570 /* 3571 * Accept explicit localhost address when 3572 * GatewayPorts=yes. The "localhost" hostname is 3573 * deliberately skipped here so it will listen on all 3574 * available local address families. 3575 */ 3576 addr = listen_addr; 3577 } 3578 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3579 strcmp(listen_addr, "::1") == 0) { 3580 /* 3581 * If a specific IPv4/IPv6 localhost address has been 3582 * requested then accept it even if gateway_ports is in 3583 * effect. This allows the client to prefer IPv4 or IPv6. 3584 */ 3585 addr = listen_addr; 3586 } 3587 if (wildcardp != NULL) 3588 *wildcardp = wildcard; 3589 return addr; 3590 } 3591 3592 static int 3593 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3594 struct Forward *fwd, int *allocated_listen_port, 3595 struct ForwardOptions *fwd_opts) 3596 { 3597 Channel *c; 3598 int sock, r, success = 0, wildcard = 0, is_client; 3599 struct addrinfo hints, *ai, *aitop; 3600 const char *host, *addr; 3601 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3602 in_port_t *lport_p; 3603 3604 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3605 3606 if (is_client && fwd->connect_path != NULL) { 3607 host = fwd->connect_path; 3608 } else { 3609 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3610 fwd->listen_host : fwd->connect_host; 3611 if (host == NULL) { 3612 error("No forward host name."); 3613 return 0; 3614 } 3615 if (strlen(host) >= NI_MAXHOST) { 3616 error("Forward host name too long."); 3617 return 0; 3618 } 3619 } 3620 3621 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3622 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3623 is_client, fwd_opts); 3624 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3625 (addr == NULL) ? "NULL" : addr); 3626 3627 /* 3628 * getaddrinfo returns a loopback address if the hostname is 3629 * set to NULL and hints.ai_flags is not AI_PASSIVE 3630 */ 3631 memset(&hints, 0, sizeof(hints)); 3632 hints.ai_family = ssh->chanctxt->IPv4or6; 3633 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3634 hints.ai_socktype = SOCK_STREAM; 3635 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3636 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3637 if (addr == NULL) { 3638 /* This really shouldn't happen */ 3639 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3640 ssh_gai_strerror(r)); 3641 } else { 3642 error_f("getaddrinfo(%.64s): %s", addr, 3643 ssh_gai_strerror(r)); 3644 } 3645 return 0; 3646 } 3647 if (allocated_listen_port != NULL) 3648 *allocated_listen_port = 0; 3649 for (ai = aitop; ai; ai = ai->ai_next) { 3650 switch (ai->ai_family) { 3651 case AF_INET: 3652 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3653 sin_port; 3654 break; 3655 case AF_INET6: 3656 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3657 sin6_port; 3658 break; 3659 default: 3660 continue; 3661 } 3662 /* 3663 * If allocating a port for -R forwards, then use the 3664 * same port for all address families. 3665 */ 3666 if (type == SSH_CHANNEL_RPORT_LISTENER && 3667 fwd->listen_port == 0 && allocated_listen_port != NULL && 3668 *allocated_listen_port > 0) 3669 *lport_p = htons(*allocated_listen_port); 3670 3671 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3672 strport, sizeof(strport), 3673 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3674 error_f("getnameinfo failed"); 3675 continue; 3676 } 3677 /* Create a port to listen for the host. */ 3678 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3679 if (sock == -1) { 3680 /* this is no error since kernel may not support ipv6 */ 3681 verbose("socket [%s]:%s: %.100s", ntop, strport, 3682 strerror(errno)); 3683 continue; 3684 } 3685 3686 set_reuseaddr(sock); 3687 3688 debug("Local forwarding listening on %s port %s.", 3689 ntop, strport); 3690 3691 /* Bind the socket to the address. */ 3692 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3693 /* 3694 * address can be in if use ipv6 address is 3695 * already bound 3696 */ 3697 verbose("bind [%s]:%s: %.100s", 3698 ntop, strport, strerror(errno)); 3699 close(sock); 3700 continue; 3701 } 3702 /* Start listening for connections on the socket. */ 3703 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3704 error("listen [%s]:%s: %.100s", ntop, strport, 3705 strerror(errno)); 3706 close(sock); 3707 continue; 3708 } 3709 3710 /* 3711 * fwd->listen_port == 0 requests a dynamically allocated port - 3712 * record what we got. 3713 */ 3714 if (type == SSH_CHANNEL_RPORT_LISTENER && 3715 fwd->listen_port == 0 && 3716 allocated_listen_port != NULL && 3717 *allocated_listen_port == 0) { 3718 *allocated_listen_port = get_local_port(sock); 3719 debug("Allocated listen port %d", 3720 *allocated_listen_port); 3721 } 3722 3723 /* Allocate a channel number for the socket. */ 3724 /* explicitly test for hpn disabled option. if true use smaller window size */ 3725 if (hpn_disabled) 3726 c = channel_new(ssh, "port listener", type, sock, sock, -1, 3727 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3728 0, "port listener", 1); 3729 else 3730 c = channel_new(ssh, "port listener", type, sock, sock, 3731 -1, hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 3732 0, "port listener", 1); 3733 c->path = xstrdup(host); 3734 c->host_port = fwd->connect_port; 3735 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3736 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3737 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3738 c->listening_port = *allocated_listen_port; 3739 else 3740 c->listening_port = fwd->listen_port; 3741 success = 1; 3742 } 3743 if (success == 0) 3744 error_f("cannot listen to port: %d", fwd->listen_port); 3745 freeaddrinfo(aitop); 3746 return success; 3747 } 3748 3749 static int 3750 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3751 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3752 { 3753 struct sockaddr_un sunaddr; 3754 const char *path; 3755 Channel *c; 3756 int port, sock; 3757 mode_t omask; 3758 3759 switch (type) { 3760 case SSH_CHANNEL_UNIX_LISTENER: 3761 if (fwd->connect_path != NULL) { 3762 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3763 error("Local connecting path too long: %s", 3764 fwd->connect_path); 3765 return 0; 3766 } 3767 path = fwd->connect_path; 3768 port = PORT_STREAMLOCAL; 3769 } else { 3770 if (fwd->connect_host == NULL) { 3771 error("No forward host name."); 3772 return 0; 3773 } 3774 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3775 error("Forward host name too long."); 3776 return 0; 3777 } 3778 path = fwd->connect_host; 3779 port = fwd->connect_port; 3780 } 3781 break; 3782 case SSH_CHANNEL_RUNIX_LISTENER: 3783 path = fwd->listen_path; 3784 port = PORT_STREAMLOCAL; 3785 break; 3786 default: 3787 error_f("unexpected channel type %d", type); 3788 return 0; 3789 } 3790 3791 if (fwd->listen_path == NULL) { 3792 error("No forward path name."); 3793 return 0; 3794 } 3795 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3796 error("Local listening path too long: %s", fwd->listen_path); 3797 return 0; 3798 } 3799 3800 debug3_f("type %d path %s", type, fwd->listen_path); 3801 3802 /* Start a Unix domain listener. */ 3803 omask = umask(fwd_opts->streamlocal_bind_mask); 3804 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3805 fwd_opts->streamlocal_bind_unlink); 3806 umask(omask); 3807 if (sock < 0) 3808 return 0; 3809 3810 debug("Local forwarding listening on path %s.", fwd->listen_path); 3811 3812 /* Allocate a channel number for the socket. */ 3813 c = channel_new(ssh, "unix listener", type, sock, sock, -1, 3814 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3815 0, "unix listener", 1); 3816 c->path = xstrdup(path); 3817 c->host_port = port; 3818 c->listening_port = PORT_STREAMLOCAL; 3819 c->listening_addr = xstrdup(fwd->listen_path); 3820 return 1; 3821 } 3822 3823 static int 3824 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3825 const char *host, u_short port) 3826 { 3827 u_int i; 3828 int found = 0; 3829 3830 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3831 Channel *c = ssh->chanctxt->channels[i]; 3832 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3833 continue; 3834 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3835 debug2_f("close channel %d", i); 3836 channel_free(ssh, c); 3837 found = 1; 3838 } 3839 } 3840 3841 return found; 3842 } 3843 3844 static int 3845 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3846 { 3847 u_int i; 3848 int found = 0; 3849 3850 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3851 Channel *c = ssh->chanctxt->channels[i]; 3852 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3853 continue; 3854 if (c->path == NULL) 3855 continue; 3856 if (strcmp(c->path, path) == 0) { 3857 debug2_f("close channel %d", i); 3858 channel_free(ssh, c); 3859 found = 1; 3860 } 3861 } 3862 3863 return found; 3864 } 3865 3866 int 3867 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3868 { 3869 if (fwd->listen_path != NULL) { 3870 return channel_cancel_rport_listener_streamlocal(ssh, 3871 fwd->listen_path); 3872 } else { 3873 return channel_cancel_rport_listener_tcpip(ssh, 3874 fwd->listen_host, fwd->listen_port); 3875 } 3876 } 3877 3878 static int 3879 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 3880 const char *lhost, u_short lport, int cport, 3881 struct ForwardOptions *fwd_opts) 3882 { 3883 u_int i; 3884 int found = 0; 3885 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 3886 3887 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3888 Channel *c = ssh->chanctxt->channels[i]; 3889 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 3890 continue; 3891 if (c->listening_port != lport) 3892 continue; 3893 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 3894 /* skip dynamic forwardings */ 3895 if (c->host_port == 0) 3896 continue; 3897 } else { 3898 if (c->host_port != cport) 3899 continue; 3900 } 3901 if ((c->listening_addr == NULL && addr != NULL) || 3902 (c->listening_addr != NULL && addr == NULL)) 3903 continue; 3904 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 3905 debug2_f("close channel %d", i); 3906 channel_free(ssh, c); 3907 found = 1; 3908 } 3909 } 3910 3911 return found; 3912 } 3913 3914 static int 3915 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 3916 { 3917 u_int i; 3918 int found = 0; 3919 3920 if (path == NULL) { 3921 error_f("no path specified."); 3922 return 0; 3923 } 3924 3925 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3926 Channel *c = ssh->chanctxt->channels[i]; 3927 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 3928 continue; 3929 if (c->listening_addr == NULL) 3930 continue; 3931 if (strcmp(c->listening_addr, path) == 0) { 3932 debug2_f("close channel %d", i); 3933 channel_free(ssh, c); 3934 found = 1; 3935 } 3936 } 3937 3938 return found; 3939 } 3940 3941 int 3942 channel_cancel_lport_listener(struct ssh *ssh, 3943 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 3944 { 3945 if (fwd->listen_path != NULL) { 3946 return channel_cancel_lport_listener_streamlocal(ssh, 3947 fwd->listen_path); 3948 } else { 3949 return channel_cancel_lport_listener_tcpip(ssh, 3950 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 3951 } 3952 } 3953 3954 /* protocol local port fwd, used by ssh */ 3955 int 3956 channel_setup_local_fwd_listener(struct ssh *ssh, 3957 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3958 { 3959 if (fwd->listen_path != NULL) { 3960 return channel_setup_fwd_listener_streamlocal(ssh, 3961 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 3962 } else { 3963 return channel_setup_fwd_listener_tcpip(ssh, 3964 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 3965 } 3966 } 3967 3968 /* Matches a remote forwarding permission against a requested forwarding */ 3969 static int 3970 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 3971 { 3972 int ret; 3973 char *lhost; 3974 3975 /* XXX add ACLs for streamlocal */ 3976 if (fwd->listen_path != NULL) 3977 return 1; 3978 3979 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 3980 return 0; 3981 3982 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 3983 allowed_open->listen_port != fwd->listen_port) 3984 return 0; 3985 3986 /* Match hostnames case-insensitively */ 3987 lhost = xstrdup(fwd->listen_host); 3988 lowercase(lhost); 3989 ret = match_pattern(lhost, allowed_open->listen_host); 3990 free(lhost); 3991 3992 return ret; 3993 } 3994 3995 /* Checks whether a requested remote forwarding is permitted */ 3996 static int 3997 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 3998 { 3999 struct ssh_channels *sc = ssh->chanctxt; 4000 struct permission_set *pset = &sc->remote_perms; 4001 u_int i, permit, permit_adm = 1; 4002 struct permission *perm; 4003 4004 /* XXX apply GatewayPorts override before checking? */ 4005 4006 permit = pset->all_permitted; 4007 if (!permit) { 4008 for (i = 0; i < pset->num_permitted_user; i++) { 4009 perm = &pset->permitted_user[i]; 4010 if (remote_open_match(perm, fwd)) { 4011 permit = 1; 4012 break; 4013 } 4014 } 4015 } 4016 4017 if (pset->num_permitted_admin > 0) { 4018 permit_adm = 0; 4019 for (i = 0; i < pset->num_permitted_admin; i++) { 4020 perm = &pset->permitted_admin[i]; 4021 if (remote_open_match(perm, fwd)) { 4022 permit_adm = 1; 4023 break; 4024 } 4025 } 4026 } 4027 4028 return permit && permit_adm; 4029 } 4030 4031 /* protocol v2 remote port fwd, used by sshd */ 4032 int 4033 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 4034 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 4035 { 4036 if (!check_rfwd_permission(ssh, fwd)) { 4037 ssh_packet_send_debug(ssh, "port forwarding refused"); 4038 if (fwd->listen_path != NULL) 4039 /* XXX always allowed, see remote_open_match() */ 4040 logit("Received request from %.100s port %d to " 4041 "remote forward to path \"%.100s\", " 4042 "but the request was denied.", 4043 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4044 fwd->listen_path); 4045 else if(fwd->listen_host != NULL) 4046 logit("Received request from %.100s port %d to " 4047 "remote forward to host %.100s port %d, " 4048 "but the request was denied.", 4049 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 4050 fwd->listen_host, fwd->listen_port ); 4051 else 4052 logit("Received request from %.100s port %d to remote " 4053 "forward, but the request was denied.", 4054 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 4055 return 0; 4056 } 4057 if (fwd->listen_path != NULL) { 4058 return channel_setup_fwd_listener_streamlocal(ssh, 4059 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4060 } else { 4061 return channel_setup_fwd_listener_tcpip(ssh, 4062 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4063 fwd_opts); 4064 } 4065 } 4066 4067 /* 4068 * Translate the requested rfwd listen host to something usable for 4069 * this server. 4070 */ 4071 static const char * 4072 channel_rfwd_bind_host(const char *listen_host) 4073 { 4074 if (listen_host == NULL) { 4075 return "localhost"; 4076 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4077 return ""; 4078 } else 4079 return listen_host; 4080 } 4081 4082 /* 4083 * Initiate forwarding of connections to port "port" on remote host through 4084 * the secure channel to host:port from local side. 4085 * Returns handle (index) for updating the dynamic listen port with 4086 * channel_update_permission(). 4087 */ 4088 int 4089 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4090 { 4091 int r, success = 0, idx = -1; 4092 char *host_to_connect, *listen_host, *listen_path; 4093 int port_to_connect, listen_port; 4094 4095 /* Send the forward request to the remote side. */ 4096 if (fwd->listen_path != NULL) { 4097 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4098 (r = sshpkt_put_cstring(ssh, 4099 "streamlocal-forward@openssh.com")) != 0 || 4100 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4101 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4102 (r = sshpkt_send(ssh)) != 0 || 4103 (r = ssh_packet_write_wait(ssh)) < 0) 4104 fatal_fr(r, "request streamlocal"); 4105 } else { 4106 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4107 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4108 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4109 (r = sshpkt_put_cstring(ssh, 4110 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4111 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4112 (r = sshpkt_send(ssh)) != 0 || 4113 (r = ssh_packet_write_wait(ssh)) < 0) 4114 fatal_fr(r, "request tcpip-forward"); 4115 } 4116 /* Assume that server accepts the request */ 4117 success = 1; 4118 if (success) { 4119 /* Record that connection to this host/port is permitted. */ 4120 host_to_connect = listen_host = listen_path = NULL; 4121 port_to_connect = listen_port = 0; 4122 if (fwd->connect_path != NULL) { 4123 host_to_connect = xstrdup(fwd->connect_path); 4124 port_to_connect = PORT_STREAMLOCAL; 4125 } else { 4126 host_to_connect = xstrdup(fwd->connect_host); 4127 port_to_connect = fwd->connect_port; 4128 } 4129 if (fwd->listen_path != NULL) { 4130 listen_path = xstrdup(fwd->listen_path); 4131 listen_port = PORT_STREAMLOCAL; 4132 } else { 4133 if (fwd->listen_host != NULL) 4134 listen_host = xstrdup(fwd->listen_host); 4135 listen_port = fwd->listen_port; 4136 } 4137 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4138 host_to_connect, port_to_connect, 4139 listen_host, listen_path, listen_port, NULL); 4140 } 4141 return idx; 4142 } 4143 4144 static int 4145 open_match(struct permission *allowed_open, const char *requestedhost, 4146 int requestedport) 4147 { 4148 if (allowed_open->host_to_connect == NULL) 4149 return 0; 4150 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4151 allowed_open->port_to_connect != requestedport) 4152 return 0; 4153 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4154 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4155 return 0; 4156 return 1; 4157 } 4158 4159 /* 4160 * Note that in the listen host/port case 4161 * we don't support FWD_PERMIT_ANY_PORT and 4162 * need to translate between the configured-host (listen_host) 4163 * and what we've sent to the remote server (channel_rfwd_bind_host) 4164 */ 4165 static int 4166 open_listen_match_tcpip(struct permission *allowed_open, 4167 const char *requestedhost, u_short requestedport, int translate) 4168 { 4169 const char *allowed_host; 4170 4171 if (allowed_open->host_to_connect == NULL) 4172 return 0; 4173 if (allowed_open->listen_port != requestedport) 4174 return 0; 4175 if (!translate && allowed_open->listen_host == NULL && 4176 requestedhost == NULL) 4177 return 1; 4178 allowed_host = translate ? 4179 channel_rfwd_bind_host(allowed_open->listen_host) : 4180 allowed_open->listen_host; 4181 if (allowed_host == NULL || requestedhost == NULL || 4182 strcmp(allowed_host, requestedhost) != 0) 4183 return 0; 4184 return 1; 4185 } 4186 4187 static int 4188 open_listen_match_streamlocal(struct permission *allowed_open, 4189 const char *requestedpath) 4190 { 4191 if (allowed_open->host_to_connect == NULL) 4192 return 0; 4193 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4194 return 0; 4195 if (allowed_open->listen_path == NULL || 4196 strcmp(allowed_open->listen_path, requestedpath) != 0) 4197 return 0; 4198 return 1; 4199 } 4200 4201 /* 4202 * Request cancellation of remote forwarding of connection host:port from 4203 * local side. 4204 */ 4205 static int 4206 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4207 const char *host, u_short port) 4208 { 4209 struct ssh_channels *sc = ssh->chanctxt; 4210 struct permission_set *pset = &sc->local_perms; 4211 int r; 4212 u_int i; 4213 struct permission *perm = NULL; 4214 4215 for (i = 0; i < pset->num_permitted_user; i++) { 4216 perm = &pset->permitted_user[i]; 4217 if (open_listen_match_tcpip(perm, host, port, 0)) 4218 break; 4219 perm = NULL; 4220 } 4221 if (perm == NULL) { 4222 debug_f("requested forward not found"); 4223 return -1; 4224 } 4225 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4226 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4227 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4228 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4229 (r = sshpkt_put_u32(ssh, port)) != 0 || 4230 (r = sshpkt_send(ssh)) != 0) 4231 fatal_fr(r, "send cancel"); 4232 4233 fwd_perm_clear(perm); /* unregister */ 4234 4235 return 0; 4236 } 4237 4238 /* 4239 * Request cancellation of remote forwarding of Unix domain socket 4240 * path from local side. 4241 */ 4242 static int 4243 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4244 { 4245 struct ssh_channels *sc = ssh->chanctxt; 4246 struct permission_set *pset = &sc->local_perms; 4247 int r; 4248 u_int i; 4249 struct permission *perm = NULL; 4250 4251 for (i = 0; i < pset->num_permitted_user; i++) { 4252 perm = &pset->permitted_user[i]; 4253 if (open_listen_match_streamlocal(perm, path)) 4254 break; 4255 perm = NULL; 4256 } 4257 if (perm == NULL) { 4258 debug_f("requested forward not found"); 4259 return -1; 4260 } 4261 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4262 (r = sshpkt_put_cstring(ssh, 4263 "cancel-streamlocal-forward@openssh.com")) != 0 || 4264 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4265 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4266 (r = sshpkt_send(ssh)) != 0) 4267 fatal_fr(r, "send cancel"); 4268 4269 fwd_perm_clear(perm); /* unregister */ 4270 4271 return 0; 4272 } 4273 4274 /* 4275 * Request cancellation of remote forwarding of a connection from local side. 4276 */ 4277 int 4278 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4279 { 4280 if (fwd->listen_path != NULL) { 4281 return channel_request_rforward_cancel_streamlocal(ssh, 4282 fwd->listen_path); 4283 } else { 4284 return channel_request_rforward_cancel_tcpip(ssh, 4285 fwd->listen_host, 4286 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4287 } 4288 } 4289 4290 /* 4291 * Permits opening to any host/port if permitted_user[] is empty. This is 4292 * usually called by the server, because the user could connect to any port 4293 * anyway, and the server has no way to know but to trust the client anyway. 4294 */ 4295 void 4296 channel_permit_all(struct ssh *ssh, int where) 4297 { 4298 struct permission_set *pset = permission_set_get(ssh, where); 4299 4300 if (pset->num_permitted_user == 0) 4301 pset->all_permitted = 1; 4302 } 4303 4304 /* 4305 * Permit the specified host/port for forwarding. 4306 */ 4307 void 4308 channel_add_permission(struct ssh *ssh, int who, int where, 4309 char *host, int port) 4310 { 4311 int local = where == FORWARD_LOCAL; 4312 struct permission_set *pset = permission_set_get(ssh, where); 4313 4314 debug("allow %s forwarding to host %s port %d", 4315 fwd_ident(who, where), host, port); 4316 /* 4317 * Remote forwards set listen_host/port, local forwards set 4318 * host/port_to_connect. 4319 */ 4320 permission_set_add(ssh, who, where, 4321 local ? host : 0, local ? port : 0, 4322 local ? NULL : host, NULL, local ? 0 : port, NULL); 4323 pset->all_permitted = 0; 4324 } 4325 4326 /* 4327 * Administratively disable forwarding. 4328 */ 4329 void 4330 channel_disable_admin(struct ssh *ssh, int where) 4331 { 4332 channel_clear_permission(ssh, FORWARD_ADM, where); 4333 permission_set_add(ssh, FORWARD_ADM, where, 4334 NULL, 0, NULL, NULL, 0, NULL); 4335 } 4336 4337 /* 4338 * Clear a list of permitted opens. 4339 */ 4340 void 4341 channel_clear_permission(struct ssh *ssh, int who, int where) 4342 { 4343 struct permission **permp; 4344 u_int *npermp; 4345 4346 permission_set_get_array(ssh, who, where, &permp, &npermp); 4347 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4348 *npermp = 0; 4349 } 4350 4351 /* 4352 * Update the listen port for a dynamic remote forward, after 4353 * the actual 'newport' has been allocated. If 'newport' < 0 is 4354 * passed then they entry will be invalidated. 4355 */ 4356 void 4357 channel_update_permission(struct ssh *ssh, int idx, int newport) 4358 { 4359 struct permission_set *pset = &ssh->chanctxt->local_perms; 4360 4361 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4362 debug_f("index out of range: %d num_permitted_user %d", 4363 idx, pset->num_permitted_user); 4364 return; 4365 } 4366 debug("%s allowed port %d for forwarding to host %s port %d", 4367 newport > 0 ? "Updating" : "Removing", 4368 newport, 4369 pset->permitted_user[idx].host_to_connect, 4370 pset->permitted_user[idx].port_to_connect); 4371 if (newport <= 0) 4372 fwd_perm_clear(&pset->permitted_user[idx]); 4373 else { 4374 pset->permitted_user[idx].listen_port = 4375 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4376 } 4377 } 4378 4379 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4380 int 4381 permitopen_port(const char *p) 4382 { 4383 int port; 4384 4385 if (strcmp(p, "*") == 0) 4386 return FWD_PERMIT_ANY_PORT; 4387 if ((port = a2port(p)) > 0) 4388 return port; 4389 return -1; 4390 } 4391 4392 /* Try to start non-blocking connect to next host in cctx list */ 4393 static int 4394 connect_next(struct channel_connect *cctx) 4395 { 4396 int sock, saved_errno; 4397 struct sockaddr_un *sunaddr; 4398 char ntop[NI_MAXHOST]; 4399 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4400 4401 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4402 switch (cctx->ai->ai_family) { 4403 case AF_UNIX: 4404 /* unix:pathname instead of host:port */ 4405 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4406 strlcpy(ntop, "unix", sizeof(ntop)); 4407 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4408 break; 4409 case AF_INET: 4410 case AF_INET6: 4411 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4412 ntop, sizeof(ntop), strport, sizeof(strport), 4413 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4414 error_f("getnameinfo failed"); 4415 continue; 4416 } 4417 break; 4418 default: 4419 continue; 4420 } 4421 debug_f("start for host %.100s ([%.100s]:%s)", 4422 cctx->host, ntop, strport); 4423 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4424 cctx->ai->ai_protocol)) == -1) { 4425 if (cctx->ai->ai_next == NULL) 4426 error("socket: %.100s", strerror(errno)); 4427 else 4428 verbose("socket: %.100s", strerror(errno)); 4429 continue; 4430 } 4431 if (set_nonblock(sock) == -1) 4432 fatal_f("set_nonblock(%d)", sock); 4433 if (connect(sock, cctx->ai->ai_addr, 4434 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4435 debug_f("host %.100s ([%.100s]:%s): %.100s", 4436 cctx->host, ntop, strport, strerror(errno)); 4437 saved_errno = errno; 4438 close(sock); 4439 errno = saved_errno; 4440 continue; /* fail -- try next */ 4441 } 4442 if (cctx->ai->ai_family != AF_UNIX) 4443 set_nodelay(sock); 4444 debug_f("connect host %.100s ([%.100s]:%s) in progress, fd=%d", 4445 cctx->host, ntop, strport, sock); 4446 cctx->ai = cctx->ai->ai_next; 4447 return sock; 4448 } 4449 return -1; 4450 } 4451 4452 static void 4453 channel_connect_ctx_free(struct channel_connect *cctx) 4454 { 4455 free(cctx->host); 4456 if (cctx->aitop) { 4457 if (cctx->aitop->ai_family == AF_UNIX) 4458 free(cctx->aitop); 4459 else 4460 freeaddrinfo(cctx->aitop); 4461 } 4462 memset(cctx, 0, sizeof(*cctx)); 4463 } 4464 4465 /* 4466 * Return connecting socket to remote host:port or local socket path, 4467 * passing back the failure reason if appropriate. 4468 */ 4469 static int 4470 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4471 const char *ctype, const char *rname, struct channel_connect *cctx, 4472 int *reason, const char **errmsg) 4473 { 4474 struct addrinfo hints; 4475 int gaierr; 4476 int sock = -1; 4477 char strport[NI_MAXSERV]; 4478 4479 if (port == PORT_STREAMLOCAL) { 4480 struct sockaddr_un *sunaddr; 4481 struct addrinfo *ai; 4482 4483 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4484 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4485 return -1; 4486 } 4487 4488 /* 4489 * Fake up a struct addrinfo for AF_UNIX connections. 4490 * channel_connect_ctx_free() must check ai_family 4491 * and use free() not freeaddirinfo() for AF_UNIX. 4492 */ 4493 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4494 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4495 ai->ai_addr = (struct sockaddr *)(ai + 1); 4496 ai->ai_addrlen = sizeof(*sunaddr); 4497 ai->ai_family = AF_UNIX; 4498 ai->ai_socktype = socktype; 4499 ai->ai_protocol = PF_UNSPEC; 4500 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4501 sunaddr->sun_family = AF_UNIX; 4502 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4503 cctx->aitop = ai; 4504 } else { 4505 memset(&hints, 0, sizeof(hints)); 4506 hints.ai_family = ssh->chanctxt->IPv4or6; 4507 hints.ai_socktype = socktype; 4508 snprintf(strport, sizeof strport, "%d", port); 4509 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4510 != 0) { 4511 if (errmsg != NULL) 4512 *errmsg = ssh_gai_strerror(gaierr); 4513 if (reason != NULL) 4514 *reason = SSH2_OPEN_CONNECT_FAILED; 4515 error("connect_to %.100s: unknown host (%s)", name, 4516 ssh_gai_strerror(gaierr)); 4517 return -1; 4518 } 4519 } 4520 4521 cctx->host = xstrdup(name); 4522 cctx->port = port; 4523 cctx->ai = cctx->aitop; 4524 4525 if ((sock = connect_next(cctx)) == -1) { 4526 error("connect to %.100s port %d failed: %s", 4527 name, port, strerror(errno)); 4528 return -1; 4529 } 4530 4531 return sock; 4532 } 4533 4534 /* Return CONNECTING channel to remote host:port or local socket path */ 4535 static Channel * 4536 connect_to(struct ssh *ssh, const char *host, int port, 4537 const char *ctype, const char *rname) 4538 { 4539 struct channel_connect cctx; 4540 Channel *c; 4541 int sock; 4542 4543 memset(&cctx, 0, sizeof(cctx)); 4544 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4545 &cctx, NULL, NULL); 4546 if (sock == -1) { 4547 channel_connect_ctx_free(&cctx); 4548 return NULL; 4549 } 4550 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4551 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4552 c->host_port = port; 4553 c->path = xstrdup(host); 4554 c->connect_ctx = cctx; 4555 4556 return c; 4557 } 4558 4559 /* 4560 * returns either the newly connected channel or the downstream channel 4561 * that needs to deal with this connection. 4562 */ 4563 Channel * 4564 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4565 u_short listen_port, const char *ctype, const char *rname) 4566 { 4567 struct ssh_channels *sc = ssh->chanctxt; 4568 struct permission_set *pset = &sc->local_perms; 4569 u_int i; 4570 struct permission *perm; 4571 4572 for (i = 0; i < pset->num_permitted_user; i++) { 4573 perm = &pset->permitted_user[i]; 4574 if (open_listen_match_tcpip(perm, 4575 listen_host, listen_port, 1)) { 4576 if (perm->downstream) 4577 return perm->downstream; 4578 if (perm->port_to_connect == 0) 4579 return rdynamic_connect_prepare(ssh, 4580 ctype, rname); 4581 return connect_to(ssh, 4582 perm->host_to_connect, perm->port_to_connect, 4583 ctype, rname); 4584 } 4585 } 4586 error("WARNING: Server requests forwarding for unknown listen_port %d", 4587 listen_port); 4588 return NULL; 4589 } 4590 4591 Channel * 4592 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4593 const char *ctype, const char *rname) 4594 { 4595 struct ssh_channels *sc = ssh->chanctxt; 4596 struct permission_set *pset = &sc->local_perms; 4597 u_int i; 4598 struct permission *perm; 4599 4600 for (i = 0; i < pset->num_permitted_user; i++) { 4601 perm = &pset->permitted_user[i]; 4602 if (open_listen_match_streamlocal(perm, path)) { 4603 return connect_to(ssh, 4604 perm->host_to_connect, perm->port_to_connect, 4605 ctype, rname); 4606 } 4607 } 4608 error("WARNING: Server requests forwarding for unknown path %.100s", 4609 path); 4610 return NULL; 4611 } 4612 4613 /* Check if connecting to that port is permitted and connect. */ 4614 Channel * 4615 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4616 const char *ctype, const char *rname, int *reason, const char **errmsg) 4617 { 4618 struct ssh_channels *sc = ssh->chanctxt; 4619 struct permission_set *pset = &sc->local_perms; 4620 struct channel_connect cctx; 4621 Channel *c; 4622 u_int i, permit, permit_adm = 1; 4623 int sock; 4624 struct permission *perm; 4625 4626 permit = pset->all_permitted; 4627 if (!permit) { 4628 for (i = 0; i < pset->num_permitted_user; i++) { 4629 perm = &pset->permitted_user[i]; 4630 if (open_match(perm, host, port)) { 4631 permit = 1; 4632 break; 4633 } 4634 } 4635 } 4636 4637 if (pset->num_permitted_admin > 0) { 4638 permit_adm = 0; 4639 for (i = 0; i < pset->num_permitted_admin; i++) { 4640 perm = &pset->permitted_admin[i]; 4641 if (open_match(perm, host, port)) { 4642 permit_adm = 1; 4643 break; 4644 } 4645 } 4646 } 4647 4648 if (!permit || !permit_adm) { 4649 logit("Received request from %.100s port %d to connect to " 4650 "host %.100s port %d, but the request was denied.", 4651 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4652 if (reason != NULL) 4653 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4654 return NULL; 4655 } 4656 4657 memset(&cctx, 0, sizeof(cctx)); 4658 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4659 &cctx, reason, errmsg); 4660 if (sock == -1) { 4661 channel_connect_ctx_free(&cctx); 4662 return NULL; 4663 } 4664 4665 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4666 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4667 c->host_port = port; 4668 c->path = xstrdup(host); 4669 c->connect_ctx = cctx; 4670 4671 return c; 4672 } 4673 4674 /* Check if connecting to that path is permitted and connect. */ 4675 Channel * 4676 channel_connect_to_path(struct ssh *ssh, const char *path, const char *ctype, 4677 const char *rname) 4678 { 4679 struct ssh_channels *sc = ssh->chanctxt; 4680 struct permission_set *pset = &sc->local_perms; 4681 u_int i, permit, permit_adm = 1; 4682 struct permission *perm; 4683 4684 permit = pset->all_permitted; 4685 if (!permit) { 4686 for (i = 0; i < pset->num_permitted_user; i++) { 4687 perm = &pset->permitted_user[i]; 4688 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4689 permit = 1; 4690 break; 4691 } 4692 } 4693 } 4694 4695 if (pset->num_permitted_admin > 0) { 4696 permit_adm = 0; 4697 for (i = 0; i < pset->num_permitted_admin; i++) { 4698 perm = &pset->permitted_admin[i]; 4699 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4700 permit_adm = 1; 4701 break; 4702 } 4703 } 4704 } 4705 4706 if (!permit || !permit_adm) { 4707 logit("Received request to connect to path %.100s, " 4708 "but the request was denied.", path); 4709 return NULL; 4710 } 4711 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4712 } 4713 4714 void 4715 channel_send_window_changes(struct ssh *ssh) 4716 { 4717 struct ssh_channels *sc = ssh->chanctxt; 4718 struct winsize ws; 4719 int r; 4720 u_int i; 4721 4722 for (i = 0; i < sc->channels_alloc; i++) { 4723 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4724 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4725 continue; 4726 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4727 continue; 4728 channel_request_start(ssh, i, "window-change", 0); 4729 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4730 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4731 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4732 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4733 (r = sshpkt_send(ssh)) != 0) 4734 fatal_fr(r, "channel %u; send window-change", i); 4735 } 4736 } 4737 4738 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4739 static Channel * 4740 rdynamic_connect_prepare(struct ssh *ssh, const char *ctype, const char *rname) 4741 { 4742 Channel *c; 4743 int r; 4744 4745 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4746 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4747 c->host_port = 0; 4748 c->path = NULL; 4749 4750 /* 4751 * We need to open the channel before we have a FD, 4752 * so that we can get SOCKS header from peer. 4753 */ 4754 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4755 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4756 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4757 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4758 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4759 fatal_fr(r, "channel %i; confirm", c->self); 4760 return c; 4761 } 4762 4763 /* Return CONNECTING socket to remote host:port or local socket path */ 4764 static int 4765 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4766 { 4767 struct ssh_channels *sc = ssh->chanctxt; 4768 struct permission_set *pset = &sc->local_perms; 4769 struct permission *perm; 4770 struct channel_connect cctx; 4771 u_int i, permit_adm = 1; 4772 int sock; 4773 4774 if (pset->num_permitted_admin > 0) { 4775 permit_adm = 0; 4776 for (i = 0; i < pset->num_permitted_admin; i++) { 4777 perm = &pset->permitted_admin[i]; 4778 if (open_match(perm, c->path, c->host_port)) { 4779 permit_adm = 1; 4780 break; 4781 } 4782 } 4783 } 4784 if (!permit_adm) { 4785 debug_f("requested forward not permitted"); 4786 return -1; 4787 } 4788 4789 memset(&cctx, 0, sizeof(cctx)); 4790 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4791 NULL, &cctx, NULL, NULL); 4792 if (sock == -1) 4793 channel_connect_ctx_free(&cctx); 4794 else { 4795 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4796 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4797 c->connect_ctx = cctx; 4798 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4799 } 4800 return sock; 4801 } 4802 4803 /* -- X11 forwarding */ 4804 4805 /* 4806 * Creates an internet domain socket for listening for X11 connections. 4807 * Returns 0 and a suitable display number for the DISPLAY variable 4808 * stored in display_numberp , or -1 if an error occurs. 4809 */ 4810 int 4811 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4812 int x11_use_localhost, int single_connection, 4813 u_int *display_numberp, int **chanids) 4814 { 4815 Channel *nc = NULL; 4816 int display_number, sock; 4817 u_short port; 4818 struct addrinfo hints, *ai, *aitop; 4819 char strport[NI_MAXSERV]; 4820 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4821 4822 if (chanids == NULL) 4823 return -1; 4824 4825 for (display_number = x11_display_offset; 4826 display_number < MAX_DISPLAYS; 4827 display_number++) { 4828 port = 6000 + display_number; 4829 memset(&hints, 0, sizeof(hints)); 4830 hints.ai_family = ssh->chanctxt->IPv4or6; 4831 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4832 hints.ai_socktype = SOCK_STREAM; 4833 snprintf(strport, sizeof strport, "%d", port); 4834 if ((gaierr = getaddrinfo(NULL, strport, 4835 &hints, &aitop)) != 0) { 4836 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4837 return -1; 4838 } 4839 for (ai = aitop; ai; ai = ai->ai_next) { 4840 if (ai->ai_family != AF_INET && 4841 ai->ai_family != AF_INET6) 4842 continue; 4843 sock = socket(ai->ai_family, ai->ai_socktype, 4844 ai->ai_protocol); 4845 if (sock == -1) { 4846 error("socket: %.100s", strerror(errno)); 4847 freeaddrinfo(aitop); 4848 return -1; 4849 } 4850 set_reuseaddr(sock); 4851 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4852 debug2_f("bind port %d: %.100s", port, 4853 strerror(errno)); 4854 close(sock); 4855 for (n = 0; n < num_socks; n++) 4856 close(socks[n]); 4857 num_socks = 0; 4858 break; 4859 } 4860 socks[num_socks++] = sock; 4861 if (num_socks == NUM_SOCKS) 4862 break; 4863 } 4864 freeaddrinfo(aitop); 4865 if (num_socks > 0) 4866 break; 4867 } 4868 if (display_number >= MAX_DISPLAYS) { 4869 error("Failed to allocate internet-domain X11 display socket."); 4870 return -1; 4871 } 4872 /* Start listening for connections on the socket. */ 4873 for (n = 0; n < num_socks; n++) { 4874 sock = socks[n]; 4875 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 4876 error("listen: %.100s", strerror(errno)); 4877 close(sock); 4878 return -1; 4879 } 4880 } 4881 4882 /* Allocate a channel for each socket. */ 4883 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 4884 for (n = 0; n < num_socks; n++) { 4885 sock = socks[n]; 4886 /* Is this really necassary? */ 4887 if (hpn_disabled) 4888 nc = channel_new(ssh, "x11 listener", 4889 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4890 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 4891 0, "X11 inet listener", 1); 4892 else 4893 nc = channel_new(ssh, "x11 listener", 4894 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4895 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 4896 0, "X11 inet listener", 1); 4897 nc->single_connection = single_connection; 4898 (*chanids)[n] = nc->self; 4899 } 4900 (*chanids)[n] = -1; 4901 4902 /* Return the display number for the DISPLAY environment variable. */ 4903 *display_numberp = display_number; 4904 return 0; 4905 } 4906 4907 static int 4908 connect_local_xsocket(u_int dnr) 4909 { 4910 int sock; 4911 struct sockaddr_un addr; 4912 4913 sock = socket(AF_UNIX, SOCK_STREAM, 0); 4914 if (sock == -1) 4915 error("socket: %.100s", strerror(errno)); 4916 memset(&addr, 0, sizeof(addr)); 4917 addr.sun_family = AF_UNIX; 4918 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 4919 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 4920 return sock; 4921 close(sock); 4922 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 4923 return -1; 4924 } 4925 4926 int 4927 x11_connect_display(struct ssh *ssh) 4928 { 4929 u_int display_number; 4930 const char *display; 4931 char buf[1024], *cp; 4932 struct addrinfo hints, *ai, *aitop; 4933 char strport[NI_MAXSERV]; 4934 int gaierr, sock = 0; 4935 4936 /* Try to open a socket for the local X server. */ 4937 display = getenv("DISPLAY"); 4938 if (!display) { 4939 error("DISPLAY not set."); 4940 return -1; 4941 } 4942 /* 4943 * Now we decode the value of the DISPLAY variable and make a 4944 * connection to the real X server. 4945 */ 4946 4947 /* 4948 * Check if it is a unix domain socket. Unix domain displays are in 4949 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 4950 */ 4951 if (strncmp(display, "unix:", 5) == 0 || 4952 display[0] == ':') { 4953 /* Connect to the unix domain socket. */ 4954 if (sscanf(strrchr(display, ':') + 1, "%u", 4955 &display_number) != 1) { 4956 error("Could not parse display number from DISPLAY: " 4957 "%.100s", display); 4958 return -1; 4959 } 4960 /* Create a socket. */ 4961 sock = connect_local_xsocket(display_number); 4962 if (sock < 0) 4963 return -1; 4964 4965 /* OK, we now have a connection to the display. */ 4966 return sock; 4967 } 4968 /* 4969 * Connect to an inet socket. The DISPLAY value is supposedly 4970 * hostname:d[.s], where hostname may also be numeric IP address. 4971 */ 4972 strlcpy(buf, display, sizeof(buf)); 4973 cp = strchr(buf, ':'); 4974 if (!cp) { 4975 error("Could not find ':' in DISPLAY: %.100s", display); 4976 return -1; 4977 } 4978 *cp = 0; 4979 /* 4980 * buf now contains the host name. But first we parse the 4981 * display number. 4982 */ 4983 if (sscanf(cp + 1, "%u", &display_number) != 1) { 4984 error("Could not parse display number from DISPLAY: %.100s", 4985 display); 4986 return -1; 4987 } 4988 4989 /* Look up the host address */ 4990 memset(&hints, 0, sizeof(hints)); 4991 hints.ai_family = ssh->chanctxt->IPv4or6; 4992 hints.ai_socktype = SOCK_STREAM; 4993 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 4994 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 4995 error("%.100s: unknown host. (%s)", buf, 4996 ssh_gai_strerror(gaierr)); 4997 return -1; 4998 } 4999 for (ai = aitop; ai; ai = ai->ai_next) { 5000 /* Create a socket. */ 5001 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 5002 if (sock == -1) { 5003 debug2("socket: %.100s", strerror(errno)); 5004 continue; 5005 } 5006 /* Connect it to the display. */ 5007 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 5008 debug2("connect %.100s port %u: %.100s", buf, 5009 6000 + display_number, strerror(errno)); 5010 close(sock); 5011 continue; 5012 } 5013 /* Success */ 5014 break; 5015 } 5016 freeaddrinfo(aitop); 5017 if (!ai) { 5018 error("connect %.100s port %u: %.100s", buf, 5019 6000 + display_number, strerror(errno)); 5020 return -1; 5021 } 5022 set_nodelay(sock); 5023 return sock; 5024 } 5025 5026 /* 5027 * Requests forwarding of X11 connections, generates fake authentication 5028 * data, and enables authentication spoofing. 5029 * This should be called in the client only. 5030 */ 5031 void 5032 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 5033 const char *disp, const char *proto, const char *data, int want_reply) 5034 { 5035 struct ssh_channels *sc = ssh->chanctxt; 5036 u_int data_len = (u_int) strlen(data) / 2; 5037 u_int i, value; 5038 const char *cp; 5039 char *new_data; 5040 int r, screen_number; 5041 5042 if (sc->x11_saved_display == NULL) 5043 sc->x11_saved_display = xstrdup(disp); 5044 else if (strcmp(disp, sc->x11_saved_display) != 0) { 5045 error("x11_request_forwarding_with_spoofing: different " 5046 "$DISPLAY already forwarded"); 5047 return; 5048 } 5049 5050 cp = strchr(disp, ':'); 5051 if (cp) 5052 cp = strchr(cp, '.'); 5053 if (cp) 5054 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 5055 else 5056 screen_number = 0; 5057 5058 if (sc->x11_saved_proto == NULL) { 5059 /* Save protocol name. */ 5060 sc->x11_saved_proto = xstrdup(proto); 5061 5062 /* Extract real authentication data. */ 5063 sc->x11_saved_data = xmalloc(data_len); 5064 for (i = 0; i < data_len; i++) { 5065 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5066 fatal("x11_request_forwarding: bad " 5067 "authentication data: %.100s", data); 5068 } 5069 sc->x11_saved_data[i] = value; 5070 } 5071 sc->x11_saved_data_len = data_len; 5072 5073 /* Generate fake data of the same length. */ 5074 sc->x11_fake_data = xmalloc(data_len); 5075 arc4random_buf(sc->x11_fake_data, data_len); 5076 sc->x11_fake_data_len = data_len; 5077 } 5078 5079 /* Convert the fake data into hex. */ 5080 new_data = tohex(sc->x11_fake_data, data_len); 5081 5082 /* Send the request packet. */ 5083 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5084 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5085 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5086 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5087 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5088 (r = sshpkt_send(ssh)) != 0 || 5089 (r = ssh_packet_write_wait(ssh)) < 0) 5090 fatal_fr(r, "send x11-req"); 5091 free(new_data); 5092 } 5093