1 /* $NetBSD: channels.c,v 1.27 2020/05/28 17:05:49 christos Exp $ */ 2 /* $OpenBSD: channels.c,v 1.398 2020/04/25 06:59:36 dtucker Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * This file contains functions for generic socket connection forwarding. 8 * There is also code for initiating connection forwarding for X11 connections, 9 * arbitrary tcp/ip connections, and the authentication agent connection. 10 * 11 * As far as I am concerned, the code I have written for this software 12 * can be used freely for any purpose. Any derived versions of this 13 * software must be clearly marked as such, and if the derived work is 14 * incompatible with the protocol description in the RFC file, it must be 15 * called by a name other than "ssh" or "Secure Shell". 16 * 17 * SSH2 support added by Markus Friedl. 18 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 19 * Copyright (c) 1999 Dug Song. All rights reserved. 20 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 32 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 34 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 41 */ 42 43 #include "includes.h" 44 __RCSID("$NetBSD: channels.c,v 1.27 2020/05/28 17:05:49 christos Exp $"); 45 #include <sys/param.h> 46 #include <sys/types.h> 47 #include <sys/stat.h> 48 #include <sys/ioctl.h> 49 #include <sys/un.h> 50 #include <sys/socket.h> 51 #include <sys/time.h> 52 #include <sys/queue.h> 53 54 #include <netinet/in.h> 55 #include <arpa/inet.h> 56 57 #include <errno.h> 58 #include <fcntl.h> 59 #include <limits.h> 60 #include <netdb.h> 61 #include <stdarg.h> 62 #include <stdint.h> 63 #include <stdio.h> 64 #include <stdlib.h> 65 #include <string.h> 66 #include <termios.h> 67 #include <unistd.h> 68 69 #include "xmalloc.h" 70 #include "ssh.h" 71 #include "ssh2.h" 72 #include "ssherr.h" 73 #include "sshbuf.h" 74 #include "packet.h" 75 #include "log.h" 76 #include "misc.h" 77 #include "channels.h" 78 #include "compat.h" 79 #include "canohost.h" 80 #include "sshkey.h" 81 #include "authfd.h" 82 #include "pathnames.h" 83 #include "match.h" 84 85 86 static int hpn_disabled = 0; 87 static int hpn_buffer_size = 2 * 1024 * 1024; 88 89 /* -- agent forwarding */ 90 #define NUM_SOCKS 10 91 92 /* -- tcp forwarding */ 93 /* special-case port number meaning allow any port */ 94 #define FWD_PERMIT_ANY_PORT 0 95 96 /* special-case wildcard meaning allow any host */ 97 #define FWD_PERMIT_ANY_HOST "*" 98 99 /* -- X11 forwarding */ 100 /* Maximum number of fake X11 displays to try. */ 101 #define MAX_DISPLAYS 1000 102 103 /* Per-channel callback for pre/post select() actions */ 104 typedef void chan_fn(struct ssh *, Channel *c, 105 fd_set *readset, fd_set *writeset); 106 107 /* 108 * Data structure for storing which hosts are permitted for forward requests. 109 * The local sides of any remote forwards are stored in this array to prevent 110 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 111 * network (which might be behind a firewall). 112 */ 113 /* XXX: streamlocal wants a path instead of host:port */ 114 /* Overload host_to_connect; we could just make this match Forward */ 115 /* XXX - can we use listen_host instead of listen_path? */ 116 struct permission { 117 char *host_to_connect; /* Connect to 'host'. */ 118 int port_to_connect; /* Connect to 'port'. */ 119 char *listen_host; /* Remote side should listen address. */ 120 char *listen_path; /* Remote side should listen path. */ 121 int listen_port; /* Remote side should listen port. */ 122 Channel *downstream; /* Downstream mux*/ 123 }; 124 125 /* 126 * Stores the forwarding permission state for a single direction (local or 127 * remote). 128 */ 129 struct permission_set { 130 /* 131 * List of all local permitted host/port pairs to allow for the 132 * user. 133 */ 134 u_int num_permitted_user; 135 struct permission *permitted_user; 136 137 /* 138 * List of all permitted host/port pairs to allow for the admin. 139 */ 140 u_int num_permitted_admin; 141 struct permission *permitted_admin; 142 143 /* 144 * If this is true, all opens/listens are permitted. This is the 145 * case on the server on which we have to trust the client anyway, 146 * and the user could do anything after logging in. 147 */ 148 int all_permitted; 149 }; 150 151 /* Master structure for channels state */ 152 struct ssh_channels { 153 /* 154 * Pointer to an array containing all allocated channels. The array 155 * is dynamically extended as needed. 156 */ 157 Channel **channels; 158 159 /* 160 * Size of the channel array. All slots of the array must always be 161 * initialized (at least the type field); unused slots set to NULL 162 */ 163 u_int channels_alloc; 164 165 /* 166 * Maximum file descriptor value used in any of the channels. This is 167 * updated in channel_new. 168 */ 169 int channel_max_fd; 170 171 /* 172 * 'channel_pre*' are called just before select() to add any bits 173 * relevant to channels in the select bitmasks. 174 * 175 * 'channel_post*': perform any appropriate operations for 176 * channels which have events pending. 177 */ 178 chan_fn **channel_pre; 179 chan_fn **channel_post; 180 181 /* -- tcp forwarding */ 182 struct permission_set local_perms; 183 struct permission_set remote_perms; 184 185 /* -- X11 forwarding */ 186 187 /* Saved X11 local (client) display. */ 188 char *x11_saved_display; 189 190 /* Saved X11 authentication protocol name. */ 191 char *x11_saved_proto; 192 193 /* Saved X11 authentication data. This is the real data. */ 194 char *x11_saved_data; 195 u_int x11_saved_data_len; 196 197 /* Deadline after which all X11 connections are refused */ 198 u_int x11_refuse_time; 199 200 /* 201 * Fake X11 authentication data. This is what the server will be 202 * sending us; we should replace any occurrences of this by the 203 * real data. 204 */ 205 u_char *x11_fake_data; 206 u_int x11_fake_data_len; 207 208 /* AF_UNSPEC or AF_INET or AF_INET6 */ 209 int IPv4or6; 210 }; 211 212 /* helper */ 213 static void port_open_helper(struct ssh *ssh, Channel *c, const char *rtype); 214 static const char *channel_rfwd_bind_host(const char *listen_host); 215 216 /* non-blocking connect helpers */ 217 static int connect_next(struct channel_connect *); 218 static void channel_connect_ctx_free(struct channel_connect *); 219 static Channel *rdynamic_connect_prepare(struct ssh *, const char *, 220 const char *); 221 static int rdynamic_connect_finish(struct ssh *, Channel *); 222 223 /* Setup helper */ 224 static void channel_handler_init(struct ssh_channels *sc); 225 226 /* -- channel core */ 227 228 void 229 channel_init_channels(struct ssh *ssh) 230 { 231 struct ssh_channels *sc; 232 233 if ((sc = calloc(1, sizeof(*sc))) == NULL) 234 fatal("%s: allocation failed", __func__); 235 sc->channels_alloc = 10; 236 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 237 sc->IPv4or6 = AF_UNSPEC; 238 channel_handler_init(sc); 239 240 ssh->chanctxt = sc; 241 } 242 243 Channel * 244 channel_by_id(struct ssh *ssh, int id) 245 { 246 Channel *c; 247 248 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 249 logit("%s: %d: bad id", __func__, id); 250 return NULL; 251 } 252 c = ssh->chanctxt->channels[id]; 253 if (c == NULL) { 254 logit("%s: %d: bad id: channel free", __func__, id); 255 return NULL; 256 } 257 return c; 258 } 259 260 Channel * 261 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 262 { 263 Channel *c; 264 u_int i; 265 266 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 267 c = ssh->chanctxt->channels[i]; 268 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 269 return c; 270 } 271 return NULL; 272 } 273 274 /* 275 * Returns the channel if it is allowed to receive protocol messages. 276 * Private channels, like listening sockets, may not receive messages. 277 */ 278 Channel * 279 channel_lookup(struct ssh *ssh, int id) 280 { 281 Channel *c; 282 283 if ((c = channel_by_id(ssh, id)) == NULL) 284 return NULL; 285 286 switch (c->type) { 287 case SSH_CHANNEL_X11_OPEN: 288 case SSH_CHANNEL_LARVAL: 289 case SSH_CHANNEL_CONNECTING: 290 case SSH_CHANNEL_DYNAMIC: 291 case SSH_CHANNEL_RDYNAMIC_OPEN: 292 case SSH_CHANNEL_RDYNAMIC_FINISH: 293 case SSH_CHANNEL_OPENING: 294 case SSH_CHANNEL_OPEN: 295 case SSH_CHANNEL_ABANDONED: 296 case SSH_CHANNEL_MUX_PROXY: 297 return c; 298 } 299 logit("Non-public channel %d, type %d.", id, c->type); 300 return NULL; 301 } 302 303 /* 304 * Register filedescriptors for a channel, used when allocating a channel or 305 * when the channel consumer/producer is ready, e.g. shell exec'd 306 */ 307 static void 308 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 309 int extusage, int nonblock, int is_tty) 310 { 311 struct ssh_channels *sc = ssh->chanctxt; 312 313 /* Update the maximum file descriptor value. */ 314 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, rfd); 315 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, wfd); 316 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, efd); 317 318 if (rfd != -1) 319 fcntl(rfd, F_SETFD, FD_CLOEXEC); 320 if (wfd != -1 && wfd != rfd) 321 fcntl(wfd, F_SETFD, FD_CLOEXEC); 322 if (efd != -1 && efd != rfd && efd != wfd) 323 fcntl(efd, F_SETFD, FD_CLOEXEC); 324 325 c->rfd = rfd; 326 c->wfd = wfd; 327 c->sock = (rfd == wfd) ? rfd : -1; 328 c->efd = efd; 329 c->extended_usage = extusage; 330 331 if ((c->isatty = is_tty) != 0) 332 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 333 334 /* enable nonblocking mode */ 335 if (nonblock) { 336 if (rfd != -1) 337 set_nonblock(rfd); 338 if (wfd != -1) 339 set_nonblock(wfd); 340 if (efd != -1) 341 set_nonblock(efd); 342 } 343 } 344 345 /* 346 * Allocate a new channel object and set its type and socket. This will cause 347 * remote_name to be freed. 348 */ 349 Channel * 350 channel_new(struct ssh *ssh, const char *ctype, int type, int rfd, int wfd, 351 int efd, u_int window, u_int maxpack, int extusage, const char *remote_name, 352 int nonblock) 353 { 354 struct ssh_channels *sc = ssh->chanctxt; 355 u_int i, found; 356 Channel *c; 357 358 /* Try to find a free slot where to put the new channel. */ 359 for (i = 0; i < sc->channels_alloc; i++) { 360 if (sc->channels[i] == NULL) { 361 /* Found a free slot. */ 362 found = i; 363 break; 364 } 365 } 366 if (i >= sc->channels_alloc) { 367 /* 368 * There are no free slots. Take last+1 slot and expand 369 * the array. 370 */ 371 found = sc->channels_alloc; 372 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 373 fatal("%s: internal error: channels_alloc %d too big", 374 __func__, sc->channels_alloc); 375 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 376 sc->channels_alloc + 10, sizeof(*sc->channels)); 377 sc->channels_alloc += 10; 378 debug2("channel: expanding %d", sc->channels_alloc); 379 } 380 /* Initialize and return new channel. */ 381 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 382 if ((c->input = sshbuf_new()) == NULL || 383 (c->output = sshbuf_new()) == NULL || 384 (c->extended = sshbuf_new()) == NULL) 385 fatal("%s: sshbuf_new failed", __func__); 386 c->ostate = CHAN_OUTPUT_OPEN; 387 c->istate = CHAN_INPUT_OPEN; 388 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 389 c->self = found; 390 c->type = type; 391 c->ctype = __UNCONST(ctype); 392 c->local_window = window; 393 c->local_window_max = window; 394 c->local_maxpacket = maxpack; 395 c->dynamic_window = 0; 396 c->remote_id = -1; 397 c->remote_name = xstrdup(remote_name); 398 c->ctl_chan = -1; 399 c->delayed = 1; /* prevent call to channel_post handler */ 400 TAILQ_INIT(&c->status_confirms); 401 debug("channel %d: new [%s]", found, remote_name); 402 return c; 403 } 404 405 static void 406 channel_find_maxfd(struct ssh_channels *sc) 407 { 408 u_int i; 409 int max = 0; 410 Channel *c; 411 412 for (i = 0; i < sc->channels_alloc; i++) { 413 c = sc->channels[i]; 414 if (c != NULL) { 415 max = MAXIMUM(max, c->rfd); 416 max = MAXIMUM(max, c->wfd); 417 max = MAXIMUM(max, c->efd); 418 } 419 } 420 sc->channel_max_fd = max; 421 } 422 423 int 424 channel_close_fd(struct ssh *ssh, int *fdp) 425 { 426 struct ssh_channels *sc = ssh->chanctxt; 427 int ret = 0, fd = *fdp; 428 429 if (fd != -1) { 430 ret = close(fd); 431 *fdp = -1; 432 if (fd == sc->channel_max_fd) 433 channel_find_maxfd(sc); 434 } 435 return ret; 436 } 437 438 /* Close all channel fd/socket. */ 439 static void 440 channel_close_fds(struct ssh *ssh, Channel *c) 441 { 442 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 443 444 channel_close_fd(ssh, &c->sock); 445 if (rfd != sock) 446 channel_close_fd(ssh, &c->rfd); 447 if (wfd != sock && wfd != rfd) 448 channel_close_fd(ssh, &c->wfd); 449 if (efd != sock && efd != rfd && efd != wfd) 450 channel_close_fd(ssh, &c->efd); 451 } 452 453 static void 454 fwd_perm_clear(struct permission *perm) 455 { 456 free(perm->host_to_connect); 457 free(perm->listen_host); 458 free(perm->listen_path); 459 memset(perm, 0, sizeof(*perm)); 460 } 461 462 /* Returns an printable name for the specified forwarding permission list */ 463 static const char * 464 fwd_ident(int who, int where) 465 { 466 if (who == FORWARD_ADM) { 467 if (where == FORWARD_LOCAL) 468 return "admin local"; 469 else if (where == FORWARD_REMOTE) 470 return "admin remote"; 471 } else if (who == FORWARD_USER) { 472 if (where == FORWARD_LOCAL) 473 return "user local"; 474 else if (where == FORWARD_REMOTE) 475 return "user remote"; 476 } 477 fatal("Unknown forward permission list %d/%d", who, where); 478 } 479 480 /* Returns the forwarding permission list for the specified direction */ 481 static struct permission_set * 482 permission_set_get(struct ssh *ssh, int where) 483 { 484 struct ssh_channels *sc = ssh->chanctxt; 485 486 switch (where) { 487 case FORWARD_LOCAL: 488 return &sc->local_perms; 489 break; 490 case FORWARD_REMOTE: 491 return &sc->remote_perms; 492 break; 493 default: 494 fatal("%s: invalid forwarding direction %d", __func__, where); 495 } 496 } 497 498 /* Returns pointers to the specified forwarding list and its element count */ 499 static void 500 permission_set_get_array(struct ssh *ssh, int who, int where, 501 struct permission ***permpp, u_int **npermpp) 502 { 503 struct permission_set *pset = permission_set_get(ssh, where); 504 505 switch (who) { 506 case FORWARD_USER: 507 *permpp = &pset->permitted_user; 508 *npermpp = &pset->num_permitted_user; 509 break; 510 case FORWARD_ADM: 511 *permpp = &pset->permitted_admin; 512 *npermpp = &pset->num_permitted_admin; 513 break; 514 default: 515 fatal("%s: invalid forwarding client %d", __func__, who); 516 } 517 } 518 519 /* Adds an entry to the spcified forwarding list */ 520 static int 521 permission_set_add(struct ssh *ssh, int who, int where, 522 const char *host_to_connect, int port_to_connect, 523 const char *listen_host, const char *listen_path, int listen_port, 524 Channel *downstream) 525 { 526 struct permission **permp; 527 u_int n, *npermp; 528 529 permission_set_get_array(ssh, who, where, &permp, &npermp); 530 531 if (*npermp >= INT_MAX) 532 fatal("%s: %s overflow", __func__, fwd_ident(who, where)); 533 534 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 535 n = (*npermp)++; 536 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 537 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 538 (*permp)[n].port_to_connect = port_to_connect; 539 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 540 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 541 (*permp)[n].listen_port = listen_port; 542 (*permp)[n].downstream = downstream; 543 #undef MAYBE_DUP 544 return (int)n; 545 } 546 547 static void 548 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 549 { 550 struct ssh_channels *sc = ssh->chanctxt; 551 struct permission_set *pset = &sc->local_perms; 552 struct permission *perm; 553 int r; 554 u_int i; 555 556 for (i = 0; i < pset->num_permitted_user; i++) { 557 perm = &pset->permitted_user[i]; 558 if (perm->downstream != c) 559 continue; 560 561 /* cancel on the server, since mux client is gone */ 562 debug("channel %d: cleanup remote forward for %s:%u", 563 c->self, perm->listen_host, perm->listen_port); 564 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 565 (r = sshpkt_put_cstring(ssh, 566 "cancel-tcpip-forward")) != 0 || 567 (r = sshpkt_put_u8(ssh, 0)) != 0 || 568 (r = sshpkt_put_cstring(ssh, 569 channel_rfwd_bind_host(perm->listen_host))) != 0 || 570 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 571 (r = sshpkt_send(ssh)) != 0) { 572 fatal("%s: channel %i: %s", __func__, 573 c->self, ssh_err(r)); 574 } 575 fwd_perm_clear(perm); /* unregister */ 576 } 577 } 578 579 /* Free the channel and close its fd/socket. */ 580 void 581 channel_free(struct ssh *ssh, Channel *c) 582 { 583 struct ssh_channels *sc = ssh->chanctxt; 584 char *s; 585 u_int i, n; 586 Channel *other; 587 struct channel_confirm *cc; 588 589 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 590 if ((other = sc->channels[i]) == NULL) 591 continue; 592 n++; 593 /* detach from mux client and prepare for closing */ 594 if (c->type == SSH_CHANNEL_MUX_CLIENT && 595 other->type == SSH_CHANNEL_MUX_PROXY && 596 other->mux_ctx == c) { 597 other->mux_ctx = NULL; 598 other->type = SSH_CHANNEL_OPEN; 599 other->istate = CHAN_INPUT_CLOSED; 600 other->ostate = CHAN_OUTPUT_CLOSED; 601 } 602 } 603 debug("channel %d: free: %s, nchannels %u", c->self, 604 c->remote_name ? c->remote_name : "???", n); 605 606 if (c->type == SSH_CHANNEL_MUX_CLIENT) 607 mux_remove_remote_forwardings(ssh, c); 608 609 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 610 s = channel_open_message(ssh); 611 debug3("channel %d: status: %s", c->self, s); 612 free(s); 613 } 614 615 channel_close_fds(ssh, c); 616 sshbuf_free(c->input); 617 sshbuf_free(c->output); 618 sshbuf_free(c->extended); 619 c->input = c->output = c->extended = NULL; 620 free(c->remote_name); 621 c->remote_name = NULL; 622 free(c->path); 623 c->path = NULL; 624 free(c->listening_addr); 625 c->listening_addr = NULL; 626 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 627 if (cc->abandon_cb != NULL) 628 cc->abandon_cb(ssh, c, cc->ctx); 629 TAILQ_REMOVE(&c->status_confirms, cc, entry); 630 freezero(cc, sizeof(*cc)); 631 } 632 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 633 c->filter_cleanup(ssh, c->self, c->filter_ctx); 634 sc->channels[c->self] = NULL; 635 freezero(c, sizeof(*c)); 636 } 637 638 void 639 channel_free_all(struct ssh *ssh) 640 { 641 u_int i; 642 struct ssh_channels *sc = ssh->chanctxt; 643 644 for (i = 0; i < sc->channels_alloc; i++) 645 if (sc->channels[i] != NULL) 646 channel_free(ssh, sc->channels[i]); 647 648 free(sc->channels); 649 sc->channels = NULL; 650 sc->channels_alloc = 0; 651 sc->channel_max_fd = 0; 652 653 free(sc->x11_saved_display); 654 sc->x11_saved_display = NULL; 655 656 free(sc->x11_saved_proto); 657 sc->x11_saved_proto = NULL; 658 659 free(sc->x11_saved_data); 660 sc->x11_saved_data = NULL; 661 sc->x11_saved_data_len = 0; 662 663 free(sc->x11_fake_data); 664 sc->x11_fake_data = NULL; 665 sc->x11_fake_data_len = 0; 666 } 667 668 /* 669 * Closes the sockets/fds of all channels. This is used to close extra file 670 * descriptors after a fork. 671 */ 672 void 673 channel_close_all(struct ssh *ssh) 674 { 675 u_int i; 676 677 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 678 if (ssh->chanctxt->channels[i] != NULL) 679 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 680 } 681 682 /* 683 * Stop listening to channels. 684 */ 685 void 686 channel_stop_listening(struct ssh *ssh) 687 { 688 u_int i; 689 Channel *c; 690 691 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 692 c = ssh->chanctxt->channels[i]; 693 if (c != NULL) { 694 switch (c->type) { 695 case SSH_CHANNEL_AUTH_SOCKET: 696 case SSH_CHANNEL_PORT_LISTENER: 697 case SSH_CHANNEL_RPORT_LISTENER: 698 case SSH_CHANNEL_X11_LISTENER: 699 case SSH_CHANNEL_UNIX_LISTENER: 700 case SSH_CHANNEL_RUNIX_LISTENER: 701 channel_close_fd(ssh, &c->sock); 702 channel_free(ssh, c); 703 break; 704 } 705 } 706 } 707 } 708 709 /* 710 * Returns true if no channel has too much buffered data, and false if one or 711 * more channel is overfull. 712 */ 713 int 714 channel_not_very_much_buffered_data(struct ssh *ssh) 715 { 716 u_int i; 717 u_int maxsize = ssh_packet_get_maxsize(ssh); 718 Channel *c; 719 720 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 721 c = ssh->chanctxt->channels[i]; 722 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 723 continue; 724 if (sshbuf_len(c->output) > maxsize) { 725 debug2("channel %d: big output buffer %zu > %u", 726 c->self, sshbuf_len(c->output), maxsize); 727 return 0; 728 } 729 } 730 return 1; 731 } 732 733 /* Returns true if any channel is still open. */ 734 int 735 channel_still_open(struct ssh *ssh) 736 { 737 u_int i; 738 Channel *c; 739 740 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 741 c = ssh->chanctxt->channels[i]; 742 if (c == NULL) 743 continue; 744 switch (c->type) { 745 case SSH_CHANNEL_X11_LISTENER: 746 case SSH_CHANNEL_PORT_LISTENER: 747 case SSH_CHANNEL_RPORT_LISTENER: 748 case SSH_CHANNEL_MUX_LISTENER: 749 case SSH_CHANNEL_CLOSED: 750 case SSH_CHANNEL_AUTH_SOCKET: 751 case SSH_CHANNEL_DYNAMIC: 752 case SSH_CHANNEL_RDYNAMIC_OPEN: 753 case SSH_CHANNEL_CONNECTING: 754 case SSH_CHANNEL_ZOMBIE: 755 case SSH_CHANNEL_ABANDONED: 756 case SSH_CHANNEL_UNIX_LISTENER: 757 case SSH_CHANNEL_RUNIX_LISTENER: 758 continue; 759 case SSH_CHANNEL_LARVAL: 760 continue; 761 case SSH_CHANNEL_OPENING: 762 case SSH_CHANNEL_OPEN: 763 case SSH_CHANNEL_RDYNAMIC_FINISH: 764 case SSH_CHANNEL_X11_OPEN: 765 case SSH_CHANNEL_MUX_CLIENT: 766 case SSH_CHANNEL_MUX_PROXY: 767 return 1; 768 default: 769 fatal("%s: bad channel type %d", __func__, c->type); 770 /* NOTREACHED */ 771 } 772 } 773 return 0; 774 } 775 776 /* Returns the id of an open channel suitable for keepaliving */ 777 int 778 channel_find_open(struct ssh *ssh) 779 { 780 u_int i; 781 Channel *c; 782 783 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 784 c = ssh->chanctxt->channels[i]; 785 if (c == NULL || !c->have_remote_id) 786 continue; 787 switch (c->type) { 788 case SSH_CHANNEL_CLOSED: 789 case SSH_CHANNEL_DYNAMIC: 790 case SSH_CHANNEL_RDYNAMIC_OPEN: 791 case SSH_CHANNEL_RDYNAMIC_FINISH: 792 case SSH_CHANNEL_X11_LISTENER: 793 case SSH_CHANNEL_PORT_LISTENER: 794 case SSH_CHANNEL_RPORT_LISTENER: 795 case SSH_CHANNEL_MUX_LISTENER: 796 case SSH_CHANNEL_MUX_CLIENT: 797 case SSH_CHANNEL_MUX_PROXY: 798 case SSH_CHANNEL_OPENING: 799 case SSH_CHANNEL_CONNECTING: 800 case SSH_CHANNEL_ZOMBIE: 801 case SSH_CHANNEL_ABANDONED: 802 case SSH_CHANNEL_UNIX_LISTENER: 803 case SSH_CHANNEL_RUNIX_LISTENER: 804 continue; 805 case SSH_CHANNEL_LARVAL: 806 case SSH_CHANNEL_AUTH_SOCKET: 807 case SSH_CHANNEL_OPEN: 808 case SSH_CHANNEL_X11_OPEN: 809 return i; 810 default: 811 fatal("%s: bad channel type %d", __func__, c->type); 812 /* NOTREACHED */ 813 } 814 } 815 return -1; 816 } 817 818 /* Returns the state of the channel's extended usage flag */ 819 const char * 820 channel_format_extended_usage(const Channel *c) 821 { 822 if (c->efd == -1) 823 return "closed"; 824 825 switch (c->extended_usage) { 826 case CHAN_EXTENDED_WRITE: 827 return "write"; 828 case CHAN_EXTENDED_READ: 829 return "read"; 830 case CHAN_EXTENDED_IGNORE: 831 return "ignore"; 832 default: 833 return "UNKNOWN"; 834 } 835 } 836 837 static char * 838 channel_format_status(const Channel *c) 839 { 840 char *ret = NULL; 841 842 xasprintf(&ret, "t%d %s%u i%u/%zu o%u/%zu e[%s]/%zu " 843 "fd %d/%d/%d sock %d cc %d", 844 c->type, 845 c->have_remote_id ? "r" : "nr", c->remote_id, 846 c->istate, sshbuf_len(c->input), 847 c->ostate, sshbuf_len(c->output), 848 channel_format_extended_usage(c), sshbuf_len(c->extended), 849 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan); 850 return ret; 851 } 852 853 /* 854 * Returns a message describing the currently open forwarded connections, 855 * suitable for sending to the client. The message contains crlf pairs for 856 * newlines. 857 */ 858 char * 859 channel_open_message(struct ssh *ssh) 860 { 861 struct sshbuf *buf; 862 Channel *c; 863 u_int i; 864 int r; 865 char *cp, *ret; 866 867 if ((buf = sshbuf_new()) == NULL) 868 fatal("%s: sshbuf_new", __func__); 869 if ((r = sshbuf_putf(buf, 870 "The following connections are open:\r\n")) != 0) 871 fatal("%s: sshbuf_putf: %s", __func__, ssh_err(r)); 872 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 873 c = ssh->chanctxt->channels[i]; 874 if (c == NULL) 875 continue; 876 switch (c->type) { 877 case SSH_CHANNEL_X11_LISTENER: 878 case SSH_CHANNEL_PORT_LISTENER: 879 case SSH_CHANNEL_RPORT_LISTENER: 880 case SSH_CHANNEL_CLOSED: 881 case SSH_CHANNEL_AUTH_SOCKET: 882 case SSH_CHANNEL_ZOMBIE: 883 case SSH_CHANNEL_ABANDONED: 884 case SSH_CHANNEL_MUX_LISTENER: 885 case SSH_CHANNEL_UNIX_LISTENER: 886 case SSH_CHANNEL_RUNIX_LISTENER: 887 continue; 888 case SSH_CHANNEL_LARVAL: 889 case SSH_CHANNEL_OPENING: 890 case SSH_CHANNEL_CONNECTING: 891 case SSH_CHANNEL_DYNAMIC: 892 case SSH_CHANNEL_RDYNAMIC_OPEN: 893 case SSH_CHANNEL_RDYNAMIC_FINISH: 894 case SSH_CHANNEL_OPEN: 895 case SSH_CHANNEL_X11_OPEN: 896 case SSH_CHANNEL_MUX_PROXY: 897 case SSH_CHANNEL_MUX_CLIENT: 898 cp = channel_format_status(c); 899 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 900 c->self, c->remote_name, cp)) != 0) { 901 free(cp); 902 fatal("%s: sshbuf_putf: %s", 903 __func__, ssh_err(r)); 904 } 905 free(cp); 906 continue; 907 default: 908 fatal("%s: bad channel type %d", __func__, c->type); 909 /* NOTREACHED */ 910 } 911 } 912 if ((ret = sshbuf_dup_string(buf)) == NULL) 913 fatal("%s: sshbuf_dup_string", __func__); 914 sshbuf_free(buf); 915 return ret; 916 } 917 918 static void 919 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 920 { 921 int r; 922 923 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 924 (r = sshpkt_put_cstring(ssh, type)) != 0 || 925 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 926 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 927 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 928 fatal("%s: channel %i: open: %s", where, c->self, ssh_err(r)); 929 } 930 } 931 932 void 933 channel_send_open(struct ssh *ssh, int id) 934 { 935 Channel *c = channel_lookup(ssh, id); 936 int r; 937 938 if (c == NULL) { 939 logit("channel_send_open: %d: bad id", id); 940 return; 941 } 942 debug2("channel %d: send open", id); 943 open_preamble(ssh, __func__, c, c->ctype); 944 if ((r = sshpkt_send(ssh)) != 0) 945 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 946 } 947 948 void 949 channel_request_start(struct ssh *ssh, int id, const char *service, 950 int wantconfirm) 951 { 952 Channel *c = channel_lookup(ssh, id); 953 int r; 954 955 if (c == NULL) { 956 logit("%s: %d: unknown channel id", __func__, id); 957 return; 958 } 959 if (!c->have_remote_id) 960 fatal(":%s: channel %d: no remote id", __func__, c->self); 961 962 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 963 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 964 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 965 (r = sshpkt_put_cstring(ssh, service)) != 0 || 966 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 967 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 968 } 969 } 970 971 void 972 channel_register_status_confirm(struct ssh *ssh, int id, 973 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 974 { 975 struct channel_confirm *cc; 976 Channel *c; 977 978 if ((c = channel_lookup(ssh, id)) == NULL) 979 fatal("%s: %d: bad id", __func__, id); 980 981 cc = xcalloc(1, sizeof(*cc)); 982 cc->cb = cb; 983 cc->abandon_cb = abandon_cb; 984 cc->ctx = ctx; 985 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 986 } 987 988 void 989 channel_register_open_confirm(struct ssh *ssh, int id, 990 channel_open_fn *fn, void *ctx) 991 { 992 Channel *c = channel_lookup(ssh, id); 993 994 if (c == NULL) { 995 logit("%s: %d: bad id", __func__, id); 996 return; 997 } 998 c->open_confirm = fn; 999 c->open_confirm_ctx = ctx; 1000 } 1001 1002 void 1003 channel_register_cleanup(struct ssh *ssh, int id, 1004 channel_callback_fn *fn, int do_close) 1005 { 1006 Channel *c = channel_by_id(ssh, id); 1007 1008 if (c == NULL) { 1009 logit("%s: %d: bad id", __func__, id); 1010 return; 1011 } 1012 c->detach_user = fn; 1013 c->detach_close = do_close; 1014 } 1015 1016 void 1017 channel_cancel_cleanup(struct ssh *ssh, int id) 1018 { 1019 Channel *c = channel_by_id(ssh, id); 1020 1021 if (c == NULL) { 1022 logit("%s: %d: bad id", __func__, id); 1023 return; 1024 } 1025 c->detach_user = NULL; 1026 c->detach_close = 0; 1027 } 1028 1029 void 1030 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1031 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1032 { 1033 Channel *c = channel_lookup(ssh, id); 1034 1035 if (c == NULL) { 1036 logit("%s: %d: bad id", __func__, id); 1037 return; 1038 } 1039 c->input_filter = ifn; 1040 c->output_filter = ofn; 1041 c->filter_ctx = ctx; 1042 c->filter_cleanup = cfn; 1043 } 1044 1045 void 1046 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1047 int extusage, int nonblock, int is_tty, u_int window_max) 1048 { 1049 Channel *c = channel_lookup(ssh, id); 1050 int r; 1051 1052 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1053 fatal("channel_activate for non-larval channel %d.", id); 1054 if (!c->have_remote_id) 1055 fatal(":%s: channel %d: no remote id", __func__, c->self); 1056 1057 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1058 c->type = SSH_CHANNEL_OPEN; 1059 c->local_window = c->local_window_max = window_max; 1060 1061 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1062 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1063 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1064 (r = sshpkt_send(ssh)) != 0) 1065 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 1066 } 1067 1068 static void 1069 channel_pre_listener(struct ssh *ssh, Channel *c, 1070 fd_set *readset, fd_set *writeset) 1071 { 1072 FD_SET(c->sock, readset); 1073 } 1074 1075 static void 1076 channel_pre_connecting(struct ssh *ssh, Channel *c, 1077 fd_set *readset, fd_set *writeset) 1078 { 1079 debug3("channel %d: waiting for connection", c->self); 1080 FD_SET(c->sock, writeset); 1081 } 1082 1083 static int 1084 channel_tcpwinsz(struct ssh *ssh) 1085 { 1086 u_int32_t tcpwinsz = 0; 1087 socklen_t optsz = sizeof(tcpwinsz); 1088 int ret = -1; 1089 1090 /* if we aren't on a socket return 128KB*/ 1091 if(!ssh_packet_connection_is_on_socket(ssh)) 1092 return(128*1024); 1093 ret = getsockopt(ssh_packet_get_connection_in(ssh), 1094 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz); 1095 /* return no more than 64MB */ 1096 if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN) 1097 tcpwinsz = BUFFER_MAX_LEN_HPN; 1098 debug2("tcpwinsz: %d for connection: %d", tcpwinsz, 1099 ssh_packet_get_connection_in(ssh)); 1100 return(tcpwinsz); 1101 } 1102 1103 static void 1104 channel_pre_open(struct ssh *ssh, Channel *c, 1105 fd_set *readset, fd_set *writeset) 1106 { 1107 u_int limit = ssh_packet_get_maxsize(ssh); 1108 1109 /* check buffer limits */ 1110 if ((!c->tcpwinsz) || (c->dynamic_window > 0)) 1111 c->tcpwinsz = channel_tcpwinsz(ssh); 1112 1113 limit = MIN(limit, 2 * c->tcpwinsz); 1114 1115 if (c->istate == CHAN_INPUT_OPEN && 1116 c->remote_window > 0 && 1117 sshbuf_len(c->input) < c->remote_window && 1118 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1119 FD_SET(c->rfd, readset); 1120 if (c->ostate == CHAN_OUTPUT_OPEN || 1121 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1122 if (sshbuf_len(c->output) > 0) { 1123 FD_SET(c->wfd, writeset); 1124 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1125 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1126 debug2("channel %d: " 1127 "obuf_empty delayed efd %d/(%zu)", c->self, 1128 c->efd, sshbuf_len(c->extended)); 1129 else 1130 chan_obuf_empty(ssh, c); 1131 } 1132 } 1133 /** XXX check close conditions, too */ 1134 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1135 c->ostate == CHAN_OUTPUT_CLOSED)) { 1136 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1137 sshbuf_len(c->extended) > 0) 1138 FD_SET(c->efd, writeset); 1139 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1140 (c->extended_usage == CHAN_EXTENDED_READ || 1141 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1142 sshbuf_len(c->extended) < c->remote_window) 1143 FD_SET(c->efd, readset); 1144 } 1145 /* XXX: What about efd? races? */ 1146 } 1147 1148 /* 1149 * This is a special state for X11 authentication spoofing. An opened X11 1150 * connection (when authentication spoofing is being done) remains in this 1151 * state until the first packet has been completely read. The authentication 1152 * data in that packet is then substituted by the real data if it matches the 1153 * fake data, and the channel is put into normal mode. 1154 * XXX All this happens at the client side. 1155 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1156 */ 1157 static int 1158 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1159 { 1160 struct ssh_channels *sc = ssh->chanctxt; 1161 u_char *ucp; 1162 u_int proto_len, data_len; 1163 1164 /* Is this being called after the refusal deadline? */ 1165 if (sc->x11_refuse_time != 0 && 1166 (u_int)monotime() >= sc->x11_refuse_time) { 1167 verbose("Rejected X11 connection after ForwardX11Timeout " 1168 "expired"); 1169 return -1; 1170 } 1171 1172 /* Check if the fixed size part of the packet is in buffer. */ 1173 if (sshbuf_len(b) < 12) 1174 return 0; 1175 1176 /* Parse the lengths of variable-length fields. */ 1177 ucp = sshbuf_mutable_ptr(b); 1178 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1179 proto_len = 256 * ucp[6] + ucp[7]; 1180 data_len = 256 * ucp[8] + ucp[9]; 1181 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1182 proto_len = ucp[6] + 256 * ucp[7]; 1183 data_len = ucp[8] + 256 * ucp[9]; 1184 } else { 1185 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1186 ucp[0]); 1187 return -1; 1188 } 1189 1190 /* Check if the whole packet is in buffer. */ 1191 if (sshbuf_len(b) < 1192 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1193 return 0; 1194 1195 /* Check if authentication protocol matches. */ 1196 if (proto_len != strlen(sc->x11_saved_proto) || 1197 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1198 debug2("X11 connection uses different authentication protocol."); 1199 return -1; 1200 } 1201 /* Check if authentication data matches our fake data. */ 1202 if (data_len != sc->x11_fake_data_len || 1203 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1204 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1205 debug2("X11 auth data does not match fake data."); 1206 return -1; 1207 } 1208 /* Check fake data length */ 1209 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1210 error("X11 fake_data_len %d != saved_data_len %d", 1211 sc->x11_fake_data_len, sc->x11_saved_data_len); 1212 return -1; 1213 } 1214 /* 1215 * Received authentication protocol and data match 1216 * our fake data. Substitute the fake data with real 1217 * data. 1218 */ 1219 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1220 sc->x11_saved_data, sc->x11_saved_data_len); 1221 return 1; 1222 } 1223 1224 static void 1225 channel_pre_x11_open(struct ssh *ssh, Channel *c, 1226 fd_set *readset, fd_set *writeset) 1227 { 1228 int ret = x11_open_helper(ssh, c->output); 1229 1230 /* c->force_drain = 1; */ 1231 1232 if (ret == 1) { 1233 c->type = SSH_CHANNEL_OPEN; 1234 channel_pre_open(ssh, c, readset, writeset); 1235 } else if (ret == -1) { 1236 logit("X11 connection rejected because of wrong authentication."); 1237 debug2("X11 rejected %d i%d/o%d", 1238 c->self, c->istate, c->ostate); 1239 chan_read_failed(ssh, c); 1240 sshbuf_reset(c->input); 1241 chan_ibuf_empty(ssh, c); 1242 sshbuf_reset(c->output); 1243 chan_write_failed(ssh, c); 1244 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1245 } 1246 } 1247 1248 static void 1249 channel_pre_mux_client(struct ssh *ssh, 1250 Channel *c, fd_set *readset, fd_set *writeset) 1251 { 1252 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1253 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1254 FD_SET(c->rfd, readset); 1255 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1256 /* clear buffer immediately (discard any partial packet) */ 1257 sshbuf_reset(c->input); 1258 chan_ibuf_empty(ssh, c); 1259 /* Start output drain. XXX just kill chan? */ 1260 chan_rcvd_oclose(ssh, c); 1261 } 1262 if (c->ostate == CHAN_OUTPUT_OPEN || 1263 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1264 if (sshbuf_len(c->output) > 0) 1265 FD_SET(c->wfd, writeset); 1266 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1267 chan_obuf_empty(ssh, c); 1268 } 1269 } 1270 1271 /* try to decode a socks4 header */ 1272 static int 1273 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1274 { 1275 const u_char *p; 1276 char *host; 1277 u_int len, have, i, found, need; 1278 char username[256]; 1279 struct { 1280 u_int8_t version; 1281 u_int8_t command; 1282 u_int16_t dest_port; 1283 struct in_addr dest_addr; 1284 } s4_req, s4_rsp; 1285 int r; 1286 1287 debug2("channel %d: decode socks4", c->self); 1288 1289 have = sshbuf_len(input); 1290 len = sizeof(s4_req); 1291 if (have < len) 1292 return 0; 1293 p = sshbuf_ptr(input); 1294 1295 need = 1; 1296 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1297 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1298 debug2("channel %d: socks4a request", c->self); 1299 /* ... and needs an extra string (the hostname) */ 1300 need = 2; 1301 } 1302 /* Check for terminating NUL on the string(s) */ 1303 for (found = 0, i = len; i < have; i++) { 1304 if (p[i] == '\0') { 1305 found++; 1306 if (found == need) 1307 break; 1308 } 1309 if (i > 1024) { 1310 /* the peer is probably sending garbage */ 1311 debug("channel %d: decode socks4: too long", 1312 c->self); 1313 return -1; 1314 } 1315 } 1316 if (found < need) 1317 return 0; 1318 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1319 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1320 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1321 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1322 debug("channels %d: decode socks4: %s", c->self, ssh_err(r)); 1323 return -1; 1324 } 1325 have = sshbuf_len(input); 1326 p = sshbuf_ptr(input); 1327 if (memchr(p, '\0', have) == NULL) { 1328 error("channel %d: decode socks4: user not nul terminated", 1329 c->self); 1330 return -1; 1331 } 1332 len = strlen(p); 1333 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1334 len++; /* trailing '\0' */ 1335 strlcpy(username, p, sizeof(username)); 1336 if ((r = sshbuf_consume(input, len)) != 0) { 1337 fatal("%s: channel %d: consume: %s", __func__, 1338 c->self, ssh_err(r)); 1339 } 1340 free(c->path); 1341 c->path = NULL; 1342 if (need == 1) { /* SOCKS4: one string */ 1343 host = inet_ntoa(s4_req.dest_addr); 1344 c->path = xstrdup(host); 1345 } else { /* SOCKS4A: two strings */ 1346 have = sshbuf_len(input); 1347 p = sshbuf_ptr(input); 1348 if (memchr(p, '\0', have) == NULL) { 1349 error("channel %d: decode socks4a: host not nul " 1350 "terminated", c->self); 1351 return -1; 1352 } 1353 len = strlen(p); 1354 debug2("channel %d: decode socks4a: host %s/%d", 1355 c->self, p, len); 1356 len++; /* trailing '\0' */ 1357 if (len > NI_MAXHOST) { 1358 error("channel %d: hostname \"%.100s\" too long", 1359 c->self, p); 1360 return -1; 1361 } 1362 c->path = xstrdup(p); 1363 if ((r = sshbuf_consume(input, len)) != 0) { 1364 fatal("%s: channel %d: consume: %s", __func__, 1365 c->self, ssh_err(r)); 1366 } 1367 } 1368 c->host_port = ntohs(s4_req.dest_port); 1369 1370 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1371 c->self, c->path, c->host_port, s4_req.command); 1372 1373 if (s4_req.command != 1) { 1374 debug("channel %d: cannot handle: %s cn %d", 1375 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1376 return -1; 1377 } 1378 s4_rsp.version = 0; /* vn: 0 for reply */ 1379 s4_rsp.command = 90; /* cd: req granted */ 1380 s4_rsp.dest_port = 0; /* ignored */ 1381 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1382 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) { 1383 fatal("%s: channel %d: append reply: %s", __func__, 1384 c->self, ssh_err(r)); 1385 } 1386 return 1; 1387 } 1388 1389 /* try to decode a socks5 header */ 1390 #define SSH_SOCKS5_AUTHDONE 0x1000 1391 #define SSH_SOCKS5_NOAUTH 0x00 1392 #define SSH_SOCKS5_IPV4 0x01 1393 #define SSH_SOCKS5_DOMAIN 0x03 1394 #define SSH_SOCKS5_IPV6 0x04 1395 #define SSH_SOCKS5_CONNECT 0x01 1396 #define SSH_SOCKS5_SUCCESS 0x00 1397 1398 static int 1399 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1400 { 1401 /* XXX use get/put_u8 instead of trusting struct padding */ 1402 struct { 1403 u_int8_t version; 1404 u_int8_t command; 1405 u_int8_t reserved; 1406 u_int8_t atyp; 1407 } s5_req, s5_rsp; 1408 u_int16_t dest_port; 1409 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1410 const u_char *p; 1411 u_int have, need, i, found, nmethods, addrlen, af; 1412 int r; 1413 1414 debug2("channel %d: decode socks5", c->self); 1415 p = sshbuf_ptr(input); 1416 if (p[0] != 0x05) 1417 return -1; 1418 have = sshbuf_len(input); 1419 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1420 /* format: ver | nmethods | methods */ 1421 if (have < 2) 1422 return 0; 1423 nmethods = p[1]; 1424 if (have < nmethods + 2) 1425 return 0; 1426 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1427 for (found = 0, i = 2; i < nmethods + 2; i++) { 1428 if (p[i] == SSH_SOCKS5_NOAUTH) { 1429 found = 1; 1430 break; 1431 } 1432 } 1433 if (!found) { 1434 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1435 c->self); 1436 return -1; 1437 } 1438 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) { 1439 fatal("%s: channel %d: consume: %s", __func__, 1440 c->self, ssh_err(r)); 1441 } 1442 /* version, method */ 1443 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1444 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) { 1445 fatal("%s: channel %d: append reply: %s", __func__, 1446 c->self, ssh_err(r)); 1447 } 1448 c->flags |= SSH_SOCKS5_AUTHDONE; 1449 debug2("channel %d: socks5 auth done", c->self); 1450 return 0; /* need more */ 1451 } 1452 debug2("channel %d: socks5 post auth", c->self); 1453 if (have < sizeof(s5_req)+1) 1454 return 0; /* need more */ 1455 memcpy(&s5_req, p, sizeof(s5_req)); 1456 if (s5_req.version != 0x05 || 1457 s5_req.command != SSH_SOCKS5_CONNECT || 1458 s5_req.reserved != 0x00) { 1459 debug2("channel %d: only socks5 connect supported", c->self); 1460 return -1; 1461 } 1462 switch (s5_req.atyp){ 1463 case SSH_SOCKS5_IPV4: 1464 addrlen = 4; 1465 af = AF_INET; 1466 break; 1467 case SSH_SOCKS5_DOMAIN: 1468 addrlen = p[sizeof(s5_req)]; 1469 af = -1; 1470 break; 1471 case SSH_SOCKS5_IPV6: 1472 addrlen = 16; 1473 af = AF_INET6; 1474 break; 1475 default: 1476 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1477 return -1; 1478 } 1479 need = sizeof(s5_req) + addrlen + 2; 1480 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1481 need++; 1482 if (have < need) 1483 return 0; 1484 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) { 1485 fatal("%s: channel %d: consume: %s", __func__, 1486 c->self, ssh_err(r)); 1487 } 1488 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1489 /* host string length */ 1490 if ((r = sshbuf_consume(input, 1)) != 0) { 1491 fatal("%s: channel %d: consume: %s", __func__, 1492 c->self, ssh_err(r)); 1493 } 1494 } 1495 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1496 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1497 debug("channel %d: parse addr/port: %s", c->self, ssh_err(r)); 1498 return -1; 1499 } 1500 dest_addr[addrlen] = '\0'; 1501 free(c->path); 1502 c->path = NULL; 1503 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1504 if (addrlen >= NI_MAXHOST) { 1505 error("channel %d: dynamic request: socks5 hostname " 1506 "\"%.100s\" too long", c->self, dest_addr); 1507 return -1; 1508 } 1509 c->path = xstrdup(dest_addr); 1510 } else { 1511 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1512 return -1; 1513 c->path = xstrdup(ntop); 1514 } 1515 c->host_port = ntohs(dest_port); 1516 1517 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1518 c->self, c->path, c->host_port, s5_req.command); 1519 1520 s5_rsp.version = 0x05; 1521 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1522 s5_rsp.reserved = 0; /* ignored */ 1523 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1524 dest_port = 0; /* ignored */ 1525 1526 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1527 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1528 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1529 fatal("%s: channel %d: append reply: %s", __func__, 1530 c->self, ssh_err(r)); 1531 return 1; 1532 } 1533 1534 Channel * 1535 channel_connect_stdio_fwd(struct ssh *ssh, 1536 const char *host_to_connect, u_short port_to_connect, int in, int out) 1537 { 1538 Channel *c; 1539 1540 debug("%s %s:%d", __func__, host_to_connect, port_to_connect); 1541 1542 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1543 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1544 0, "stdio-forward", /*nonblock*/0); 1545 1546 c->path = xstrdup(host_to_connect); 1547 c->host_port = port_to_connect; 1548 c->listening_port = 0; 1549 c->force_drain = 1; 1550 1551 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1552 port_open_helper(ssh, c, "direct-tcpip"); 1553 1554 return c; 1555 } 1556 1557 /* dynamic port forwarding */ 1558 static void 1559 channel_pre_dynamic(struct ssh *ssh, Channel *c, 1560 fd_set *readset, fd_set *writeset) 1561 { 1562 const u_char *p; 1563 u_int have; 1564 int ret; 1565 1566 have = sshbuf_len(c->input); 1567 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1568 /* sshbuf_dump(c->input, stderr); */ 1569 /* check if the fixed size part of the packet is in buffer. */ 1570 if (have < 3) { 1571 /* need more */ 1572 FD_SET(c->sock, readset); 1573 return; 1574 } 1575 /* try to guess the protocol */ 1576 p = sshbuf_ptr(c->input); 1577 /* XXX sshbuf_peek_u8? */ 1578 switch (p[0]) { 1579 case 0x04: 1580 ret = channel_decode_socks4(c, c->input, c->output); 1581 break; 1582 case 0x05: 1583 ret = channel_decode_socks5(c, c->input, c->output); 1584 break; 1585 default: 1586 ret = -1; 1587 break; 1588 } 1589 if (ret < 0) { 1590 chan_mark_dead(ssh, c); 1591 } else if (ret == 0) { 1592 debug2("channel %d: pre_dynamic: need more", c->self); 1593 /* need more */ 1594 FD_SET(c->sock, readset); 1595 if (sshbuf_len(c->output)) 1596 FD_SET(c->sock, writeset); 1597 } else { 1598 /* switch to the next state */ 1599 c->type = SSH_CHANNEL_OPENING; 1600 port_open_helper(ssh, c, "direct-tcpip"); 1601 } 1602 } 1603 1604 /* simulate read-error */ 1605 static void 1606 rdynamic_close(struct ssh *ssh, Channel *c) 1607 { 1608 c->type = SSH_CHANNEL_OPEN; 1609 chan_read_failed(ssh, c); 1610 sshbuf_reset(c->input); 1611 chan_ibuf_empty(ssh, c); 1612 sshbuf_reset(c->output); 1613 chan_write_failed(ssh, c); 1614 } 1615 1616 /* reverse dynamic port forwarding */ 1617 static void 1618 channel_before_prepare_select_rdynamic(struct ssh *ssh, Channel *c) 1619 { 1620 const u_char *p; 1621 u_int have, len; 1622 int r, ret; 1623 1624 have = sshbuf_len(c->output); 1625 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1626 /* sshbuf_dump(c->output, stderr); */ 1627 /* EOF received */ 1628 if (c->flags & CHAN_EOF_RCVD) { 1629 if ((r = sshbuf_consume(c->output, have)) != 0) { 1630 fatal("%s: channel %d: consume: %s", 1631 __func__, c->self, ssh_err(r)); 1632 } 1633 rdynamic_close(ssh, c); 1634 return; 1635 } 1636 /* check if the fixed size part of the packet is in buffer. */ 1637 if (have < 3) 1638 return; 1639 /* try to guess the protocol */ 1640 p = sshbuf_ptr(c->output); 1641 switch (p[0]) { 1642 case 0x04: 1643 /* switch input/output for reverse forwarding */ 1644 ret = channel_decode_socks4(c, c->output, c->input); 1645 break; 1646 case 0x05: 1647 ret = channel_decode_socks5(c, c->output, c->input); 1648 break; 1649 default: 1650 ret = -1; 1651 break; 1652 } 1653 if (ret < 0) { 1654 rdynamic_close(ssh, c); 1655 } else if (ret == 0) { 1656 debug2("channel %d: pre_rdynamic: need more", c->self); 1657 /* send socks request to peer */ 1658 len = sshbuf_len(c->input); 1659 if (len > 0 && len < c->remote_window) { 1660 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1661 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1662 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1663 (r = sshpkt_send(ssh)) != 0) { 1664 fatal("%s: channel %i: rdynamic: %s", __func__, 1665 c->self, ssh_err(r)); 1666 } 1667 if ((r = sshbuf_consume(c->input, len)) != 0) { 1668 fatal("%s: channel %d: consume: %s", 1669 __func__, c->self, ssh_err(r)); 1670 } 1671 c->remote_window -= len; 1672 } 1673 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1674 /* the connect failed */ 1675 rdynamic_close(ssh, c); 1676 } 1677 } 1678 1679 /* This is our fake X11 server socket. */ 1680 static void 1681 channel_post_x11_listener(struct ssh *ssh, Channel *c, 1682 fd_set *readset, fd_set *writeset) 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 (!FD_ISSET(c->sock, readset)) 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->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("%s: channel %i: reply %s", __func__, 1724 c->self, ssh_err(r)); 1725 } 1726 if ((r = sshpkt_send(ssh)) != 0) 1727 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); 1728 free(remote_ipaddr); 1729 } 1730 1731 static void 1732 port_open_helper(struct ssh *ssh, Channel *c, const char *rtype) 1733 { 1734 char *local_ipaddr = get_local_ipaddr(c->sock); 1735 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1736 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1737 int remote_port = get_peer_port(c->sock); 1738 int r; 1739 1740 if (remote_port == -1) { 1741 /* Fake addr/port to appease peers that validate it (Tectia) */ 1742 free(remote_ipaddr); 1743 remote_ipaddr = xstrdup("127.0.0.1"); 1744 remote_port = 65535; 1745 } 1746 1747 free(c->remote_name); 1748 xasprintf(&c->remote_name, 1749 "%s: listening port %d for %.100s port %d, " 1750 "connect from %.200s port %d to %.100s port %d", 1751 rtype, c->listening_port, c->path, c->host_port, 1752 remote_ipaddr, remote_port, local_ipaddr, local_port); 1753 1754 open_preamble(ssh, __func__, c, rtype); 1755 if (strcmp(rtype, "direct-tcpip") == 0) { 1756 /* target host, port */ 1757 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1758 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) { 1759 fatal("%s: channel %i: reply %s", __func__, 1760 c->self, ssh_err(r)); 1761 } 1762 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1763 /* target path */ 1764 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { 1765 fatal("%s: channel %i: reply %s", __func__, 1766 c->self, ssh_err(r)); 1767 } 1768 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1769 /* listen path */ 1770 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { 1771 fatal("%s: channel %i: reply %s", __func__, 1772 c->self, ssh_err(r)); 1773 } 1774 } else { 1775 /* listen address, port */ 1776 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1777 (r = sshpkt_put_u32(ssh, local_port)) != 0) { 1778 fatal("%s: channel %i: reply %s", __func__, 1779 c->self, ssh_err(r)); 1780 } 1781 } 1782 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1783 /* reserved for future owner/mode info */ 1784 if ((r = sshpkt_put_cstring(ssh, "")) != 0) { 1785 fatal("%s: channel %i: reply %s", __func__, 1786 c->self, ssh_err(r)); 1787 } 1788 } else { 1789 /* originator host and port */ 1790 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1791 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) { 1792 fatal("%s: channel %i: reply %s", __func__, 1793 c->self, ssh_err(r)); 1794 } 1795 } 1796 if ((r = sshpkt_send(ssh)) != 0) 1797 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); 1798 free(remote_ipaddr); 1799 free(local_ipaddr); 1800 } 1801 1802 void 1803 channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time) 1804 { 1805 ssh->chanctxt->x11_refuse_time = refuse_time; 1806 } 1807 1808 /* 1809 * This socket is listening for connections to a forwarded TCP/IP port. 1810 */ 1811 static void 1812 channel_post_port_listener(struct ssh *ssh, Channel *c, 1813 fd_set *readset, fd_set *writeset) 1814 { 1815 Channel *nc; 1816 struct sockaddr_storage addr; 1817 int newsock, nextstate; 1818 socklen_t addrlen; 1819 const char *rtype; 1820 1821 if (!FD_ISSET(c->sock, readset)) 1822 return; 1823 1824 debug("Connection to port %d forwarding to %.100s port %d requested.", 1825 c->listening_port, c->path, c->host_port); 1826 1827 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1828 nextstate = SSH_CHANNEL_OPENING; 1829 rtype = "forwarded-tcpip"; 1830 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1831 nextstate = SSH_CHANNEL_OPENING; 1832 rtype = "forwarded-streamlocal@openssh.com"; 1833 } else if (c->host_port == PORT_STREAMLOCAL) { 1834 nextstate = SSH_CHANNEL_OPENING; 1835 rtype = "direct-streamlocal@openssh.com"; 1836 } else if (c->host_port == 0) { 1837 nextstate = SSH_CHANNEL_DYNAMIC; 1838 rtype = "dynamic-tcpip"; 1839 } else { 1840 nextstate = SSH_CHANNEL_OPENING; 1841 rtype = "direct-tcpip"; 1842 } 1843 1844 addrlen = sizeof(addr); 1845 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1846 if (newsock == -1) { 1847 if (errno != EINTR && errno != EWOULDBLOCK && 1848 errno != ECONNABORTED) 1849 error("accept: %.100s", strerror(errno)); 1850 if (errno == EMFILE || errno == ENFILE) 1851 c->notbefore = monotime() + 1; 1852 return; 1853 } 1854 if (c->host_port != PORT_STREAMLOCAL) 1855 set_nodelay(newsock); 1856 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1857 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1858 nc->listening_port = c->listening_port; 1859 nc->host_port = c->host_port; 1860 if (c->path != NULL) 1861 nc->path = xstrdup(c->path); 1862 1863 if (nextstate != SSH_CHANNEL_DYNAMIC) 1864 port_open_helper(ssh, nc, rtype); 1865 } 1866 1867 /* 1868 * This is the authentication agent socket listening for connections from 1869 * clients. 1870 */ 1871 static void 1872 channel_post_auth_listener(struct ssh *ssh, Channel *c, 1873 fd_set *readset, fd_set *writeset) 1874 { 1875 Channel *nc; 1876 int r, newsock; 1877 struct sockaddr_storage addr; 1878 socklen_t addrlen; 1879 1880 if (!FD_ISSET(c->sock, readset)) 1881 return; 1882 1883 addrlen = sizeof(addr); 1884 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1885 if (newsock == -1) { 1886 error("accept from auth socket: %.100s", strerror(errno)); 1887 if (errno == EMFILE || errno == ENFILE) 1888 c->notbefore = monotime() + 1; 1889 return; 1890 } 1891 nc = channel_new(ssh, "accepted auth socket", 1892 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1893 c->local_window_max, c->local_maxpacket, 1894 0, "accepted auth socket", 1); 1895 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1896 if ((r = sshpkt_send(ssh)) != 0) 1897 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 1898 } 1899 1900 static void 1901 channel_post_connecting(struct ssh *ssh, Channel *c, 1902 fd_set *readset, fd_set *writeset) 1903 { 1904 int err = 0, sock, isopen, r; 1905 socklen_t sz = sizeof(err); 1906 1907 if (!FD_ISSET(c->sock, writeset)) 1908 return; 1909 if (!c->have_remote_id) 1910 fatal(":%s: channel %d: no remote id", __func__, c->self); 1911 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1912 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1913 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 1914 err = errno; 1915 error("getsockopt SO_ERROR failed"); 1916 } 1917 if (err == 0) { 1918 debug("channel %d: connected to %s port %d", 1919 c->self, c->connect_ctx.host, c->connect_ctx.port); 1920 channel_connect_ctx_free(&c->connect_ctx); 1921 c->type = SSH_CHANNEL_OPEN; 1922 if (isopen) { 1923 /* no message necessary */ 1924 } else { 1925 if ((r = sshpkt_start(ssh, 1926 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1927 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1928 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1929 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1930 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) 1931 != 0) 1932 fatal("%s: channel %i: confirm: %s", __func__, 1933 c->self, ssh_err(r)); 1934 if ((r = sshpkt_send(ssh)) != 0) 1935 fatal("%s: channel %i: %s", __func__, c->self, 1936 ssh_err(r)); 1937 } 1938 } else { 1939 debug("channel %d: connection failed: %s", 1940 c->self, strerror(err)); 1941 /* Try next address, if any */ 1942 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1943 close(c->sock); 1944 c->sock = c->rfd = c->wfd = sock; 1945 channel_find_maxfd(ssh->chanctxt); 1946 return; 1947 } 1948 /* Exhausted all addresses */ 1949 error("connect_to %.100s port %d: failed.", 1950 c->connect_ctx.host, c->connect_ctx.port); 1951 channel_connect_ctx_free(&c->connect_ctx); 1952 if (isopen) { 1953 rdynamic_close(ssh, c); 1954 } else { 1955 if ((r = sshpkt_start(ssh, 1956 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1957 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1958 (r = sshpkt_put_u32(ssh, 1959 SSH2_OPEN_CONNECT_FAILED)) != 0 || 1960 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 1961 (r = sshpkt_put_cstring(ssh, "")) != 0) { 1962 fatal("%s: channel %i: failure: %s", __func__, 1963 c->self, ssh_err(r)); 1964 } 1965 if ((r = sshpkt_send(ssh)) != 0) 1966 fatal("%s: channel %i: %s", __func__, c->self, 1967 ssh_err(r)); 1968 chan_mark_dead(ssh, c); 1969 } 1970 } 1971 } 1972 1973 static int 1974 channel_handle_rfd(struct ssh *ssh, Channel *c, 1975 fd_set *readset, fd_set *writeset) 1976 { 1977 char buf[CHAN_RBUF]; 1978 ssize_t len; 1979 int r; 1980 1981 if (c->rfd == -1 || !FD_ISSET(c->rfd, readset)) 1982 return 1; 1983 1984 len = read(c->rfd, buf, sizeof(buf)); 1985 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 1986 return 1; 1987 if (len <= 0) { 1988 debug2("channel %d: read<=0 rfd %d len %zd", 1989 c->self, c->rfd, len); 1990 if (c->type != SSH_CHANNEL_OPEN) { 1991 debug2("channel %d: not open", c->self); 1992 chan_mark_dead(ssh, c); 1993 return -1; 1994 } else { 1995 chan_read_failed(ssh, c); 1996 } 1997 return -1; 1998 } 1999 if (c->input_filter != NULL) { 2000 if (c->input_filter(ssh, c, buf, len) == -1) { 2001 debug2("channel %d: filter stops", c->self); 2002 chan_read_failed(ssh, c); 2003 } 2004 } else if (c->datagram) { 2005 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 2006 fatal("%s: channel %d: put datagram: %s", __func__, 2007 c->self, ssh_err(r)); 2008 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { 2009 fatal("%s: channel %d: put data: %s", __func__, 2010 c->self, ssh_err(r)); 2011 } 2012 return 1; 2013 } 2014 2015 static int 2016 channel_handle_wfd(struct ssh *ssh, Channel *c, 2017 fd_set *readset, fd_set *writeset) 2018 { 2019 struct termios tio; 2020 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 2021 size_t dlen, olen = 0; 2022 int r, len; 2023 2024 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || 2025 sshbuf_len(c->output) == 0) 2026 return 1; 2027 2028 /* Send buffered output data to the socket. */ 2029 olen = sshbuf_len(c->output); 2030 if (c->output_filter != NULL) { 2031 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 2032 debug2("channel %d: filter stops", c->self); 2033 if (c->type != SSH_CHANNEL_OPEN) 2034 chan_mark_dead(ssh, c); 2035 else 2036 chan_write_failed(ssh, c); 2037 return -1; 2038 } 2039 } else if (c->datagram) { 2040 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2041 fatal("%s: channel %d: get datagram: %s", __func__, 2042 c->self, ssh_err(r)); 2043 buf = data; 2044 } else { 2045 buf = data = sshbuf_mutable_ptr(c->output); 2046 dlen = sshbuf_len(c->output); 2047 } 2048 2049 if (c->datagram) { 2050 /* ignore truncated writes, datagrams might get lost */ 2051 len = write(c->wfd, buf, dlen); 2052 free(data); 2053 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2054 return 1; 2055 if (len <= 0) 2056 goto write_fail; 2057 goto out; 2058 } 2059 2060 len = write(c->wfd, buf, dlen); 2061 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2062 return 1; 2063 if (len <= 0) { 2064 write_fail: 2065 if (c->type != SSH_CHANNEL_OPEN) { 2066 debug2("channel %d: not open", c->self); 2067 chan_mark_dead(ssh, c); 2068 return -1; 2069 } else { 2070 chan_write_failed(ssh, c); 2071 } 2072 return -1; 2073 } 2074 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2075 if (tcgetattr(c->wfd, &tio) == 0 && 2076 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2077 /* 2078 * Simulate echo to reduce the impact of 2079 * traffic analysis. We need to match the 2080 * size of a SSH2_MSG_CHANNEL_DATA message 2081 * (4 byte channel id + buf) 2082 */ 2083 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2084 (r = sshpkt_send(ssh)) != 0) 2085 fatal("%s: channel %d: ignore: %s", 2086 __func__, c->self, ssh_err(r)); 2087 } 2088 } 2089 if ((r = sshbuf_consume(c->output, len)) != 0) { 2090 fatal("%s: channel %d: consume: %s", 2091 __func__, c->self, ssh_err(r)); 2092 } 2093 out: 2094 c->local_consumed += olen - sshbuf_len(c->output); 2095 2096 return 1; 2097 } 2098 2099 static int 2100 channel_handle_efd_write(struct ssh *ssh, Channel *c, 2101 fd_set *readset, fd_set *writeset) 2102 { 2103 int r; 2104 ssize_t len; 2105 2106 if (!FD_ISSET(c->efd, writeset) || sshbuf_len(c->extended) == 0) 2107 return 1; 2108 2109 len = write(c->efd, sshbuf_ptr(c->extended), 2110 sshbuf_len(c->extended)); 2111 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2112 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2113 return 1; 2114 if (len <= 0) { 2115 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2116 channel_close_fd(ssh, &c->efd); 2117 } else { 2118 if ((r = sshbuf_consume(c->extended, len)) != 0) { 2119 fatal("%s: channel %d: consume: %s", 2120 __func__, c->self, ssh_err(r)); 2121 } 2122 c->local_consumed += len; 2123 } 2124 return 1; 2125 } 2126 2127 static int 2128 channel_handle_efd_read(struct ssh *ssh, Channel *c, 2129 fd_set *readset, fd_set *writeset) 2130 { 2131 char buf[CHAN_RBUF]; 2132 int r; 2133 ssize_t len; 2134 2135 if (!FD_ISSET(c->efd, readset)) 2136 return 1; 2137 2138 len = read(c->efd, buf, sizeof(buf)); 2139 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2140 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2141 return 1; 2142 if (len <= 0) { 2143 debug2("channel %d: closing read-efd %d", 2144 c->self, c->efd); 2145 channel_close_fd(ssh, &c->efd); 2146 } else { 2147 if (c->extended_usage == CHAN_EXTENDED_IGNORE) { 2148 debug3("channel %d: discard efd", 2149 c->self); 2150 } else if ((r = sshbuf_put(c->extended, buf, len)) != 0) { 2151 fatal("%s: channel %d: append: %s", 2152 __func__, c->self, ssh_err(r)); 2153 } 2154 } 2155 return 1; 2156 } 2157 2158 static int 2159 channel_handle_efd(struct ssh *ssh, Channel *c, 2160 fd_set *readset, fd_set *writeset) 2161 { 2162 if (c->efd == -1) 2163 return 1; 2164 2165 /** XXX handle drain efd, too */ 2166 2167 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2168 return channel_handle_efd_write(ssh, c, readset, writeset); 2169 else if (c->extended_usage == CHAN_EXTENDED_READ || 2170 c->extended_usage == CHAN_EXTENDED_IGNORE) 2171 return channel_handle_efd_read(ssh, c, readset, writeset); 2172 2173 return 1; 2174 } 2175 2176 static int 2177 channel_check_window(struct ssh *ssh, Channel *c) 2178 { 2179 int r; 2180 2181 if (c->type == SSH_CHANNEL_OPEN && 2182 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2183 ((c->local_window_max - c->local_window > 2184 c->local_maxpacket*3) || 2185 c->local_window < c->local_window_max/2) && 2186 c->local_consumed > 0) { 2187 u_int addition = 0; 2188 2189 if (!c->have_remote_id) 2190 fatal(":%s: channel %d: no remote id", 2191 __func__, c->self); 2192 2193 /* adjust max window size if we are in a dynamic environment */ 2194 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) { 2195 /* grow the window somewhat aggressively to maintain 2196 * pressure */ 2197 addition = 1.5*(c->tcpwinsz - c->local_window_max); 2198 c->local_window_max += addition; 2199 } 2200 if ((r = sshpkt_start(ssh, 2201 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2202 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2203 (r = sshpkt_put_u32(ssh, c->local_consumed + addition)) != 0 || 2204 (r = sshpkt_send(ssh)) != 0) { 2205 fatal("%s: channel %i: %s", __func__, 2206 c->self, ssh_err(r)); 2207 } 2208 debug2("channel %d: window %d sent adjust %d", 2209 c->self, c->local_window, 2210 c->local_consumed); 2211 c->local_window += c->local_consumed + addition; 2212 c->local_consumed = 0; 2213 } 2214 return 1; 2215 } 2216 2217 static void 2218 channel_post_open(struct ssh *ssh, Channel *c, 2219 fd_set *readset, fd_set *writeset) 2220 { 2221 channel_handle_rfd(ssh, c, readset, writeset); 2222 channel_handle_wfd(ssh, c, readset, writeset); 2223 channel_handle_efd(ssh, c, readset, writeset); 2224 channel_check_window(ssh, c); 2225 } 2226 2227 static u_int 2228 read_mux(struct ssh *ssh, Channel *c, u_int need) 2229 { 2230 char buf[CHAN_RBUF]; 2231 ssize_t len; 2232 u_int rlen; 2233 int r; 2234 2235 if (sshbuf_len(c->input) < need) { 2236 rlen = need - sshbuf_len(c->input); 2237 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2238 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2239 return sshbuf_len(c->input); 2240 if (len <= 0) { 2241 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2242 c->self, c->rfd, len); 2243 chan_read_failed(ssh, c); 2244 return 0; 2245 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { 2246 fatal("%s: channel %d: append: %s", 2247 __func__, c->self, ssh_err(r)); 2248 } 2249 } 2250 return sshbuf_len(c->input); 2251 } 2252 2253 static void 2254 channel_post_mux_client_read(struct ssh *ssh, Channel *c, 2255 fd_set *readset, fd_set *writeset) 2256 { 2257 u_int need; 2258 2259 if (c->rfd == -1 || !FD_ISSET(c->rfd, readset)) 2260 return; 2261 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2262 return; 2263 if (c->mux_pause) 2264 return; 2265 2266 /* 2267 * Don't not read past the precise end of packets to 2268 * avoid disrupting fd passing. 2269 */ 2270 if (read_mux(ssh, c, 4) < 4) /* read header */ 2271 return; 2272 /* XXX sshbuf_peek_u32 */ 2273 need = PEEK_U32(sshbuf_ptr(c->input)); 2274 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2275 if (need > CHANNEL_MUX_MAX_PACKET) { 2276 debug2("channel %d: packet too big %u > %u", 2277 c->self, CHANNEL_MUX_MAX_PACKET, need); 2278 chan_rcvd_oclose(ssh, c); 2279 return; 2280 } 2281 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2282 return; 2283 if (c->mux_rcb(ssh, c) != 0) { 2284 debug("channel %d: mux_rcb failed", c->self); 2285 chan_mark_dead(ssh, c); 2286 return; 2287 } 2288 } 2289 2290 static void 2291 channel_post_mux_client_write(struct ssh *ssh, Channel *c, 2292 fd_set *readset, fd_set *writeset) 2293 { 2294 ssize_t len; 2295 int r; 2296 2297 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || 2298 sshbuf_len(c->output) == 0) 2299 return; 2300 2301 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2302 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2303 return; 2304 if (len <= 0) { 2305 chan_mark_dead(ssh, c); 2306 return; 2307 } 2308 if ((r = sshbuf_consume(c->output, len)) != 0) 2309 fatal("%s: channel %d: consume: %s", __func__, 2310 c->self, ssh_err(r)); 2311 } 2312 2313 static void 2314 channel_post_mux_client(struct ssh *ssh, Channel *c, 2315 fd_set *readset, fd_set *writeset) 2316 { 2317 channel_post_mux_client_read(ssh, c, readset, writeset); 2318 channel_post_mux_client_write(ssh, c, readset, writeset); 2319 } 2320 2321 static void 2322 channel_post_mux_listener(struct ssh *ssh, Channel *c, 2323 fd_set *readset, fd_set *writeset) 2324 { 2325 Channel *nc; 2326 struct sockaddr_storage addr; 2327 socklen_t addrlen; 2328 int newsock; 2329 uid_t euid; 2330 gid_t egid; 2331 2332 if (!FD_ISSET(c->sock, readset)) 2333 return; 2334 2335 debug("multiplexing control connection"); 2336 2337 /* 2338 * Accept connection on control socket 2339 */ 2340 memset(&addr, 0, sizeof(addr)); 2341 addrlen = sizeof(addr); 2342 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2343 &addrlen)) == -1) { 2344 error("%s accept: %s", __func__, strerror(errno)); 2345 if (errno == EMFILE || errno == ENFILE) 2346 c->notbefore = monotime() + 1; 2347 return; 2348 } 2349 2350 if (getpeereid(newsock, &euid, &egid) == -1) { 2351 error("%s getpeereid failed: %s", __func__, 2352 strerror(errno)); 2353 close(newsock); 2354 return; 2355 } 2356 if ((euid != 0) && (getuid() != euid)) { 2357 error("multiplex uid mismatch: peer euid %u != uid %u", 2358 (u_int)euid, (u_int)getuid()); 2359 close(newsock); 2360 return; 2361 } 2362 nc = channel_new(ssh, "multiplex client", SSH_CHANNEL_MUX_CLIENT, 2363 newsock, newsock, -1, c->local_window_max, 2364 c->local_maxpacket, 0, "mux-control", 1); 2365 nc->mux_rcb = c->mux_rcb; 2366 debug3("%s: new mux channel %d fd %d", __func__, nc->self, nc->sock); 2367 /* establish state */ 2368 nc->mux_rcb(ssh, nc); 2369 /* mux state transitions must not elicit protocol messages */ 2370 nc->flags |= CHAN_LOCAL; 2371 } 2372 2373 static void 2374 channel_handler_init(struct ssh_channels *sc) 2375 { 2376 chan_fn **pre, **post; 2377 2378 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2379 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2380 fatal("%s: allocation failed", __func__); 2381 2382 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2383 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2384 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2385 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2386 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2387 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2388 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2389 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2390 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2391 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2392 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2393 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2394 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2395 2396 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2397 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2398 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2399 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2400 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2401 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2402 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2403 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2404 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2405 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2406 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2407 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2408 2409 sc->channel_pre = pre; 2410 sc->channel_post = post; 2411 } 2412 2413 /* gc dead channels */ 2414 static void 2415 channel_garbage_collect(struct ssh *ssh, Channel *c) 2416 { 2417 if (c == NULL) 2418 return; 2419 if (c->detach_user != NULL) { 2420 if (!chan_is_dead(ssh, c, c->detach_close)) 2421 return; 2422 2423 debug2("channel %d: gc: notify user", c->self); 2424 c->detach_user(ssh, c->self, NULL); 2425 /* if we still have a callback */ 2426 if (c->detach_user != NULL) 2427 return; 2428 debug2("channel %d: gc: user detached", c->self); 2429 } 2430 if (!chan_is_dead(ssh, c, 1)) 2431 return; 2432 debug2("channel %d: garbage collecting", c->self); 2433 channel_free(ssh, c); 2434 } 2435 2436 enum channel_table { CHAN_PRE, CHAN_POST }; 2437 2438 static void 2439 channel_handler(struct ssh *ssh, int table, 2440 fd_set *readset, fd_set *writeset, time_t *unpause_secs) 2441 { 2442 struct ssh_channels *sc = ssh->chanctxt; 2443 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2444 u_int i, oalloc; 2445 Channel *c; 2446 time_t now; 2447 2448 now = monotime(); 2449 if (unpause_secs != NULL) 2450 *unpause_secs = 0; 2451 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2452 c = sc->channels[i]; 2453 if (c == NULL) 2454 continue; 2455 if (c->delayed) { 2456 if (table == CHAN_PRE) 2457 c->delayed = 0; 2458 else 2459 continue; 2460 } 2461 if (ftab[c->type] != NULL) { 2462 /* 2463 * Run handlers that are not paused. 2464 */ 2465 if (c->notbefore <= now) 2466 (*ftab[c->type])(ssh, c, readset, writeset); 2467 else if (unpause_secs != NULL) { 2468 /* 2469 * Collect the time that the earliest 2470 * channel comes off pause. 2471 */ 2472 debug3("%s: chan %d: skip for %d more seconds", 2473 __func__, c->self, 2474 (int)(c->notbefore - now)); 2475 if (*unpause_secs == 0 || 2476 (c->notbefore - now) < *unpause_secs) 2477 *unpause_secs = c->notbefore - now; 2478 } 2479 } 2480 channel_garbage_collect(ssh, c); 2481 } 2482 if (unpause_secs != NULL && *unpause_secs != 0) 2483 debug3("%s: first channel unpauses in %d seconds", 2484 __func__, (int)*unpause_secs); 2485 } 2486 2487 /* 2488 * Create sockets before allocating the select bitmasks. 2489 * This is necessary for things that need to happen after reading 2490 * the network-input but before channel_prepare_select(). 2491 */ 2492 static void 2493 channel_before_prepare_select(struct ssh *ssh) 2494 { 2495 struct ssh_channels *sc = ssh->chanctxt; 2496 Channel *c; 2497 u_int i, oalloc; 2498 2499 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2500 c = sc->channels[i]; 2501 if (c == NULL) 2502 continue; 2503 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2504 channel_before_prepare_select_rdynamic(ssh, c); 2505 } 2506 } 2507 2508 /* 2509 * Allocate/update select bitmasks and add any bits relevant to channels in 2510 * select bitmasks. 2511 */ 2512 void 2513 channel_prepare_select(struct ssh *ssh, fd_set **readsetp, fd_set **writesetp, 2514 int *maxfdp, u_int *nallocp, time_t *minwait_secs) 2515 { 2516 u_int n, sz, nfdset; 2517 2518 channel_before_prepare_select(ssh); /* might update channel_max_fd */ 2519 2520 n = MAXIMUM(*maxfdp, ssh->chanctxt->channel_max_fd); 2521 2522 nfdset = howmany(n+1, NFDBITS); 2523 /* Explicitly test here, because xrealloc isn't always called */ 2524 if (nfdset && SIZE_MAX / nfdset < sizeof(fd_mask)) 2525 fatal("channel_prepare_select: max_fd (%d) is too large", n); 2526 sz = nfdset * sizeof(fd_mask); 2527 2528 /* perhaps check sz < nalloc/2 and shrink? */ 2529 if (*readsetp == NULL || sz > *nallocp) { 2530 *readsetp = xreallocarray(*readsetp, nfdset, sizeof(fd_mask)); 2531 *writesetp = xreallocarray(*writesetp, nfdset, sizeof(fd_mask)); 2532 *nallocp = sz; 2533 } 2534 *maxfdp = n; 2535 memset(*readsetp, 0, sz); 2536 memset(*writesetp, 0, sz); 2537 2538 if (!ssh_packet_is_rekeying(ssh)) 2539 channel_handler(ssh, CHAN_PRE, *readsetp, *writesetp, 2540 minwait_secs); 2541 } 2542 2543 /* 2544 * After select, perform any appropriate operations for channels which have 2545 * events pending. 2546 */ 2547 void 2548 channel_after_select(struct ssh *ssh, fd_set *readset, fd_set *writeset) 2549 { 2550 channel_handler(ssh, CHAN_POST, readset, writeset, NULL); 2551 } 2552 2553 /* 2554 * Enqueue data for channels with open or draining c->input. 2555 */ 2556 static void 2557 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2558 { 2559 size_t len, plen; 2560 const u_char *pkt; 2561 int r; 2562 2563 if ((len = sshbuf_len(c->input)) == 0) { 2564 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2565 /* 2566 * input-buffer is empty and read-socket shutdown: 2567 * tell peer, that we will not send more data: 2568 * send IEOF. 2569 * hack for extended data: delay EOF if EFD still 2570 * in use. 2571 */ 2572 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2573 debug2("channel %d: " 2574 "ibuf_empty delayed efd %d/(%zu)", 2575 c->self, c->efd, sshbuf_len(c->extended)); 2576 else 2577 chan_ibuf_empty(ssh, c); 2578 } 2579 return; 2580 } 2581 2582 if (!c->have_remote_id) 2583 fatal(":%s: channel %d: no remote id", __func__, c->self); 2584 2585 if (c->datagram) { 2586 /* Check datagram will fit; drop if not */ 2587 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2588 fatal("%s: channel %d: get datagram: %s", __func__, 2589 c->self, ssh_err(r)); 2590 /* 2591 * XXX this does tail-drop on the datagram queue which is 2592 * usually suboptimal compared to head-drop. Better to have 2593 * backpressure at read time? (i.e. read + discard) 2594 */ 2595 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2596 debug("channel %d: datagram too big", c->self); 2597 return; 2598 } 2599 /* Enqueue it */ 2600 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2601 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2602 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2603 (r = sshpkt_send(ssh)) != 0) { 2604 fatal("%s: channel %i: datagram: %s", __func__, 2605 c->self, ssh_err(r)); 2606 } 2607 c->remote_window -= plen; 2608 return; 2609 } 2610 2611 /* Enqueue packet for buffered data. */ 2612 if (len > c->remote_window) 2613 len = c->remote_window; 2614 if (len > c->remote_maxpacket) 2615 len = c->remote_maxpacket; 2616 if (len == 0) 2617 return; 2618 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2619 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2620 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2621 (r = sshpkt_send(ssh)) != 0) { 2622 fatal("%s: channel %i: data: %s", __func__, 2623 c->self, ssh_err(r)); 2624 } 2625 if ((r = sshbuf_consume(c->input, len)) != 0) 2626 fatal("%s: channel %i: consume: %s", __func__, 2627 c->self, ssh_err(r)); 2628 c->remote_window -= len; 2629 } 2630 2631 /* 2632 * Enqueue data for channels with open c->extended in read mode. 2633 */ 2634 static void 2635 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2636 { 2637 size_t len; 2638 int r; 2639 2640 if ((len = sshbuf_len(c->extended)) == 0) 2641 return; 2642 2643 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2644 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2645 if (len > c->remote_window) 2646 len = c->remote_window; 2647 if (len > c->remote_maxpacket) 2648 len = c->remote_maxpacket; 2649 if (len == 0) 2650 return; 2651 if (!c->have_remote_id) 2652 fatal(":%s: channel %d: no remote id", __func__, c->self); 2653 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2654 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2655 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2656 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2657 (r = sshpkt_send(ssh)) != 0) { 2658 fatal("%s: channel %i: data: %s", __func__, 2659 c->self, ssh_err(r)); 2660 } 2661 if ((r = sshbuf_consume(c->extended, len)) != 0) 2662 fatal("%s: channel %i: consume: %s", __func__, 2663 c->self, ssh_err(r)); 2664 c->remote_window -= len; 2665 debug2("channel %d: sent ext data %zu", c->self, len); 2666 } 2667 2668 /* If there is data to send to the connection, enqueue some of it now. */ 2669 void 2670 channel_output_poll(struct ssh *ssh) 2671 { 2672 struct ssh_channels *sc = ssh->chanctxt; 2673 Channel *c; 2674 u_int i; 2675 2676 for (i = 0; i < sc->channels_alloc; i++) { 2677 c = sc->channels[i]; 2678 if (c == NULL) 2679 continue; 2680 2681 /* 2682 * We are only interested in channels that can have buffered 2683 * incoming data. 2684 */ 2685 if (c->type != SSH_CHANNEL_OPEN) 2686 continue; 2687 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2688 /* XXX is this true? */ 2689 debug3("channel %d: will not send data after close", 2690 c->self); 2691 continue; 2692 } 2693 2694 /* Get the amount of buffered data for this channel. */ 2695 if (c->istate == CHAN_INPUT_OPEN || 2696 c->istate == CHAN_INPUT_WAIT_DRAIN) 2697 channel_output_poll_input_open(ssh, c); 2698 /* Send extended data, i.e. stderr */ 2699 if (!(c->flags & CHAN_EOF_SENT) && 2700 c->extended_usage == CHAN_EXTENDED_READ) 2701 channel_output_poll_extended_read(ssh, c); 2702 } 2703 } 2704 2705 /* -- mux proxy support */ 2706 2707 /* 2708 * When multiplexing channel messages for mux clients we have to deal 2709 * with downstream messages from the mux client and upstream messages 2710 * from the ssh server: 2711 * 1) Handling downstream messages is straightforward and happens 2712 * in channel_proxy_downstream(): 2713 * - We forward all messages (mostly) unmodified to the server. 2714 * - However, in order to route messages from upstream to the correct 2715 * downstream client, we have to replace the channel IDs used by the 2716 * mux clients with a unique channel ID because the mux clients might 2717 * use conflicting channel IDs. 2718 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 2719 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 2720 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 2721 * with the newly allocated channel ID. 2722 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 2723 * channels and processed by channel_proxy_upstream(). The local channel ID 2724 * is then translated back to the original mux client ID. 2725 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 2726 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 2727 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 2728 * downstream mux client are removed. 2729 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 2730 * requires more work, because they are not addressed to a specific 2731 * channel. E.g. client_request_forwarded_tcpip() needs to figure 2732 * out whether the request is addressed to the local client or a 2733 * specific downstream client based on the listen-address/port. 2734 * 6) Agent and X11-Forwarding have a similar problem and are currently 2735 * not supported as the matching session/channel cannot be identified 2736 * easily. 2737 */ 2738 2739 /* 2740 * receive packets from downstream mux clients: 2741 * channel callback fired on read from mux client, creates 2742 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 2743 * on channel creation. 2744 */ 2745 int 2746 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 2747 { 2748 Channel *c = NULL; 2749 struct sshbuf *original = NULL, *modified = NULL; 2750 const u_char *cp; 2751 char *ctype = NULL, *listen_host = NULL; 2752 u_char type; 2753 size_t have; 2754 int ret = -1, r; 2755 u_int id, remote_id, listen_port; 2756 2757 /* sshbuf_dump(downstream->input, stderr); */ 2758 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 2759 != 0) { 2760 error("%s: malformed message: %s", __func__, ssh_err(r)); 2761 return -1; 2762 } 2763 if (have < 2) { 2764 error("%s: short message", __func__); 2765 return -1; 2766 } 2767 type = cp[1]; 2768 /* skip padlen + type */ 2769 cp += 2; 2770 have -= 2; 2771 if (ssh_packet_log_type(type)) 2772 debug3("%s: channel %u: down->up: type %u", __func__, 2773 downstream->self, type); 2774 2775 switch (type) { 2776 case SSH2_MSG_CHANNEL_OPEN: 2777 if ((original = sshbuf_from(cp, have)) == NULL || 2778 (modified = sshbuf_new()) == NULL) { 2779 error("%s: alloc", __func__); 2780 goto out; 2781 } 2782 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 2783 (r = sshbuf_get_u32(original, &id)) != 0) { 2784 error("%s: parse error %s", __func__, ssh_err(r)); 2785 goto out; 2786 } 2787 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2788 -1, -1, -1, 0, 0, 0, ctype, 1); 2789 c->mux_ctx = downstream; /* point to mux client */ 2790 c->mux_downstream_id = id; /* original downstream id */ 2791 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 2792 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2793 (r = sshbuf_putb(modified, original)) != 0) { 2794 error("%s: compose error %s", __func__, ssh_err(r)); 2795 channel_free(ssh, c); 2796 goto out; 2797 } 2798 break; 2799 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2800 /* 2801 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 2802 * need to parse 'remote_id' instead of 'ctype'. 2803 */ 2804 if ((original = sshbuf_from(cp, have)) == NULL || 2805 (modified = sshbuf_new()) == NULL) { 2806 error("%s: alloc", __func__); 2807 goto out; 2808 } 2809 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 2810 (r = sshbuf_get_u32(original, &id)) != 0) { 2811 error("%s: parse error %s", __func__, ssh_err(r)); 2812 goto out; 2813 } 2814 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2815 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 2816 c->mux_ctx = downstream; /* point to mux client */ 2817 c->mux_downstream_id = id; 2818 c->remote_id = remote_id; 2819 c->have_remote_id = 1; 2820 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 2821 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2822 (r = sshbuf_putb(modified, original)) != 0) { 2823 error("%s: compose error %s", __func__, ssh_err(r)); 2824 channel_free(ssh, c); 2825 goto out; 2826 } 2827 break; 2828 case SSH2_MSG_GLOBAL_REQUEST: 2829 if ((original = sshbuf_from(cp, have)) == NULL) { 2830 error("%s: alloc", __func__); 2831 goto out; 2832 } 2833 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 2834 error("%s: parse error %s", __func__, ssh_err(r)); 2835 goto out; 2836 } 2837 if (strcmp(ctype, "tcpip-forward") != 0) { 2838 error("%s: unsupported request %s", __func__, ctype); 2839 goto out; 2840 } 2841 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 2842 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 2843 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 2844 error("%s: parse error %s", __func__, ssh_err(r)); 2845 goto out; 2846 } 2847 if (listen_port > 65535) { 2848 error("%s: tcpip-forward for %s: bad port %u", 2849 __func__, listen_host, listen_port); 2850 goto out; 2851 } 2852 /* Record that connection to this host/port is permitted. */ 2853 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 2854 listen_host, NULL, (int)listen_port, downstream); 2855 listen_host = NULL; 2856 break; 2857 case SSH2_MSG_CHANNEL_CLOSE: 2858 if (have < 4) 2859 break; 2860 remote_id = PEEK_U32(cp); 2861 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 2862 if (c->flags & CHAN_CLOSE_RCVD) 2863 channel_free(ssh, c); 2864 else 2865 c->flags |= CHAN_CLOSE_SENT; 2866 } 2867 break; 2868 } 2869 if (modified) { 2870 if ((r = sshpkt_start(ssh, type)) != 0 || 2871 (r = sshpkt_putb(ssh, modified)) != 0 || 2872 (r = sshpkt_send(ssh)) != 0) { 2873 error("%s: send %s", __func__, ssh_err(r)); 2874 goto out; 2875 } 2876 } else { 2877 if ((r = sshpkt_start(ssh, type)) != 0 || 2878 (r = sshpkt_put(ssh, cp, have)) != 0 || 2879 (r = sshpkt_send(ssh)) != 0) { 2880 error("%s: send %s", __func__, ssh_err(r)); 2881 goto out; 2882 } 2883 } 2884 ret = 0; 2885 out: 2886 free(ctype); 2887 free(listen_host); 2888 sshbuf_free(original); 2889 sshbuf_free(modified); 2890 return ret; 2891 } 2892 2893 /* 2894 * receive packets from upstream server and de-multiplex packets 2895 * to correct downstream: 2896 * implemented as a helper for channel input handlers, 2897 * replaces local (proxy) channel ID with downstream channel ID. 2898 */ 2899 int 2900 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 2901 { 2902 struct sshbuf *b = NULL; 2903 Channel *downstream; 2904 const u_char *cp = NULL; 2905 size_t len; 2906 int r; 2907 2908 /* 2909 * When receiving packets from the peer we need to check whether we 2910 * need to forward the packets to the mux client. In this case we 2911 * restore the original channel id and keep track of CLOSE messages, 2912 * so we can cleanup the channel. 2913 */ 2914 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 2915 return 0; 2916 if ((downstream = c->mux_ctx) == NULL) 2917 return 0; 2918 switch (type) { 2919 case SSH2_MSG_CHANNEL_CLOSE: 2920 case SSH2_MSG_CHANNEL_DATA: 2921 case SSH2_MSG_CHANNEL_EOF: 2922 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 2923 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2924 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 2925 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 2926 case SSH2_MSG_CHANNEL_SUCCESS: 2927 case SSH2_MSG_CHANNEL_FAILURE: 2928 case SSH2_MSG_CHANNEL_REQUEST: 2929 break; 2930 default: 2931 debug2("%s: channel %u: unsupported type %u", __func__, 2932 c->self, type); 2933 return 0; 2934 } 2935 if ((b = sshbuf_new()) == NULL) { 2936 error("%s: alloc reply", __func__); 2937 goto out; 2938 } 2939 /* get remaining payload (after id) */ 2940 cp = sshpkt_ptr(ssh, &len); 2941 if (cp == NULL) { 2942 error("%s: no packet", __func__); 2943 goto out; 2944 } 2945 /* translate id and send to muxclient */ 2946 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 2947 (r = sshbuf_put_u8(b, type)) != 0 || 2948 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 2949 (r = sshbuf_put(b, cp, len)) != 0 || 2950 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 2951 error("%s: compose for muxclient %s", __func__, ssh_err(r)); 2952 goto out; 2953 } 2954 /* sshbuf_dump(b, stderr); */ 2955 if (ssh_packet_log_type(type)) 2956 debug3("%s: channel %u: up->down: type %u", __func__, c->self, 2957 type); 2958 out: 2959 /* update state */ 2960 switch (type) { 2961 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2962 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 2963 if (cp && len > 4) { 2964 c->remote_id = PEEK_U32(cp); 2965 c->have_remote_id = 1; 2966 } 2967 break; 2968 case SSH2_MSG_CHANNEL_CLOSE: 2969 if (c->flags & CHAN_CLOSE_SENT) 2970 channel_free(ssh, c); 2971 else 2972 c->flags |= CHAN_CLOSE_RCVD; 2973 break; 2974 } 2975 sshbuf_free(b); 2976 return 1; 2977 } 2978 2979 /* -- protocol input */ 2980 2981 /* Parse a channel ID from the current packet */ 2982 static int 2983 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 2984 { 2985 u_int32_t id; 2986 int r; 2987 2988 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 2989 error("%s: parse id: %s", where, ssh_err(r)); 2990 ssh_packet_disconnect(ssh, "Invalid %s message", what); 2991 } 2992 if (id > INT_MAX) { 2993 error("%s: bad channel id %u: %s", where, id, ssh_err(r)); 2994 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 2995 } 2996 return (int)id; 2997 } 2998 2999 /* Lookup a channel from an ID in the current packet */ 3000 static Channel * 3001 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3002 { 3003 int id = channel_parse_id(ssh, where, what); 3004 Channel *c; 3005 3006 if ((c = channel_lookup(ssh, id)) == NULL) { 3007 ssh_packet_disconnect(ssh, 3008 "%s packet referred to nonexistent channel %d", what, id); 3009 } 3010 return c; 3011 } 3012 3013 int 3014 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3015 { 3016 const u_char *data; 3017 size_t data_len, win_len; 3018 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3019 int r; 3020 3021 if (channel_proxy_upstream(c, type, seq, ssh)) 3022 return 0; 3023 3024 /* Ignore any data for non-open channels (might happen on close) */ 3025 if (c->type != SSH_CHANNEL_OPEN && 3026 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3027 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3028 c->type != SSH_CHANNEL_X11_OPEN) 3029 return 0; 3030 3031 /* Get the data. */ 3032 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3033 (r = sshpkt_get_end(ssh)) != 0) 3034 fatal("%s: channel %d: get data: %s", __func__, 3035 c->self, ssh_err(r)); 3036 3037 win_len = data_len; 3038 if (c->datagram) 3039 win_len += 4; /* string length header */ 3040 3041 /* 3042 * The sending side reduces its window as it sends data, so we 3043 * must 'fake' consumption of the data in order to ensure that window 3044 * updates are sent back. Otherwise the connection might deadlock. 3045 */ 3046 if (c->ostate != CHAN_OUTPUT_OPEN) { 3047 c->local_window -= win_len; 3048 c->local_consumed += win_len; 3049 return 0; 3050 } 3051 3052 if (win_len > c->local_maxpacket) { 3053 logit("channel %d: rcvd big packet %zu, maxpack %u", 3054 c->self, win_len, c->local_maxpacket); 3055 return 0; 3056 } 3057 if (win_len > c->local_window) { 3058 logit("channel %d: rcvd too much data %zu, win %u", 3059 c->self, win_len, c->local_window); 3060 return 0; 3061 } 3062 c->local_window -= win_len; 3063 3064 if (c->datagram) { 3065 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3066 fatal("%s: channel %d: append datagram: %s", 3067 __func__, c->self, ssh_err(r)); 3068 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3069 fatal("%s: channel %d: append data: %s", 3070 __func__, c->self, ssh_err(r)); 3071 3072 return 0; 3073 } 3074 3075 int 3076 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3077 { 3078 const u_char *data; 3079 size_t data_len; 3080 u_int32_t tcode; 3081 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3082 int r; 3083 3084 if (channel_proxy_upstream(c, type, seq, ssh)) 3085 return 0; 3086 if (c->type != SSH_CHANNEL_OPEN) { 3087 logit("channel %d: ext data for non open", c->self); 3088 return 0; 3089 } 3090 if (c->flags & CHAN_EOF_RCVD) { 3091 if (datafellows & SSH_BUG_EXTEOF) 3092 debug("channel %d: accepting ext data after eof", 3093 c->self); 3094 else 3095 ssh_packet_disconnect(ssh, "Received extended_data " 3096 "after EOF on channel %d.", c->self); 3097 } 3098 3099 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3100 error("%s: parse tcode: %s", __func__, ssh_err(r)); 3101 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3102 } 3103 if (c->efd == -1 || 3104 c->extended_usage != CHAN_EXTENDED_WRITE || 3105 tcode != SSH2_EXTENDED_DATA_STDERR) { 3106 logit("channel %d: bad ext data", c->self); 3107 return 0; 3108 } 3109 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3110 (r = sshpkt_get_end(ssh)) != 0) { 3111 error("%s: parse data: %s", __func__, ssh_err(r)); 3112 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3113 } 3114 3115 if (data_len > c->local_window) { 3116 logit("channel %d: rcvd too much extended_data %zu, win %u", 3117 c->self, data_len, c->local_window); 3118 return 0; 3119 } 3120 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3121 /* XXX sshpkt_getb? */ 3122 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3123 error("%s: append: %s", __func__, ssh_err(r)); 3124 c->local_window -= data_len; 3125 return 0; 3126 } 3127 3128 int 3129 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3130 { 3131 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3132 int r; 3133 3134 if ((r = sshpkt_get_end(ssh)) != 0) { 3135 error("%s: parse data: %s", __func__, ssh_err(r)); 3136 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3137 } 3138 3139 if (channel_proxy_upstream(c, type, seq, ssh)) 3140 return 0; 3141 chan_rcvd_ieof(ssh, c); 3142 3143 /* XXX force input close */ 3144 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3145 debug("channel %d: FORCE input drain", c->self); 3146 c->istate = CHAN_INPUT_WAIT_DRAIN; 3147 if (sshbuf_len(c->input) == 0) 3148 chan_ibuf_empty(ssh, c); 3149 } 3150 return 0; 3151 } 3152 3153 int 3154 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3155 { 3156 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3157 int r; 3158 3159 if (channel_proxy_upstream(c, type, seq, ssh)) 3160 return 0; 3161 if ((r = sshpkt_get_end(ssh)) != 0) { 3162 error("%s: parse data: %s", __func__, ssh_err(r)); 3163 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3164 } 3165 chan_rcvd_oclose(ssh, c); 3166 return 0; 3167 } 3168 3169 int 3170 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3171 { 3172 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3173 u_int32_t remote_window, remote_maxpacket; 3174 int r; 3175 3176 if (channel_proxy_upstream(c, type, seq, ssh)) 3177 return 0; 3178 if (c->type != SSH_CHANNEL_OPENING) 3179 ssh_packet_disconnect(ssh, "Received open confirmation for " 3180 "non-opening channel %d.", c->self); 3181 /* 3182 * Record the remote channel number and mark that the channel 3183 * is now open. 3184 */ 3185 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3186 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3187 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3188 (r = sshpkt_get_end(ssh)) != 0) { 3189 error("%s: window/maxpacket: %s", __func__, ssh_err(r)); 3190 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3191 } 3192 3193 c->have_remote_id = 1; 3194 c->remote_window = remote_window; 3195 c->remote_maxpacket = remote_maxpacket; 3196 c->type = SSH_CHANNEL_OPEN; 3197 if (c->open_confirm) { 3198 debug2("%s: channel %d: callback start", __func__, c->self); 3199 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3200 debug2("%s: channel %d: callback done", __func__, c->self); 3201 } 3202 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3203 c->remote_window, c->remote_maxpacket); 3204 return 0; 3205 } 3206 3207 static const char * 3208 reason2txt(int reason) 3209 { 3210 switch (reason) { 3211 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3212 return "administratively prohibited"; 3213 case SSH2_OPEN_CONNECT_FAILED: 3214 return "connect failed"; 3215 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3216 return "unknown channel type"; 3217 case SSH2_OPEN_RESOURCE_SHORTAGE: 3218 return "resource shortage"; 3219 } 3220 return "unknown reason"; 3221 } 3222 3223 int 3224 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3225 { 3226 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3227 u_int32_t reason; 3228 char *msg = NULL; 3229 int r; 3230 3231 if (channel_proxy_upstream(c, type, seq, ssh)) 3232 return 0; 3233 if (c->type != SSH_CHANNEL_OPENING) 3234 ssh_packet_disconnect(ssh, "Received open failure for " 3235 "non-opening channel %d.", c->self); 3236 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3237 error("%s: reason: %s", __func__, ssh_err(r)); 3238 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3239 } 3240 /* skip language */ 3241 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3242 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3243 (r = sshpkt_get_end(ssh)) != 0) { 3244 error("%s: message/lang: %s", __func__, ssh_err(r)); 3245 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3246 } 3247 logit("channel %d: open failed: %s%s%s", c->self, 3248 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3249 free(msg); 3250 if (c->open_confirm) { 3251 debug2("%s: channel %d: callback start", __func__, c->self); 3252 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3253 debug2("%s: channel %d: callback done", __func__, c->self); 3254 } 3255 /* Schedule the channel for cleanup/deletion. */ 3256 chan_mark_dead(ssh, c); 3257 return 0; 3258 } 3259 3260 int 3261 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3262 { 3263 int id = channel_parse_id(ssh, __func__, "window adjust"); 3264 Channel *c; 3265 u_int32_t adjust; 3266 u_int new_rwin; 3267 int r; 3268 3269 if ((c = channel_lookup(ssh, id)) == NULL) { 3270 logit("Received window adjust for non-open channel %d.", id); 3271 return 0; 3272 } 3273 3274 if (channel_proxy_upstream(c, type, seq, ssh)) 3275 return 0; 3276 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3277 (r = sshpkt_get_end(ssh)) != 0) { 3278 error("%s: adjust: %s", __func__, ssh_err(r)); 3279 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3280 } 3281 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3282 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3283 fatal("channel %d: adjust %u overflows remote window %u", 3284 c->self, adjust, c->remote_window); 3285 } 3286 c->remote_window = new_rwin; 3287 return 0; 3288 } 3289 3290 int 3291 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3292 { 3293 int id = channel_parse_id(ssh, __func__, "status confirm"); 3294 Channel *c; 3295 struct channel_confirm *cc; 3296 3297 /* Reset keepalive timeout */ 3298 ssh_packet_set_alive_timeouts(ssh, 0); 3299 3300 debug2("%s: type %d id %d", __func__, type, id); 3301 3302 if ((c = channel_lookup(ssh, id)) == NULL) { 3303 logit("%s: %d: unknown", __func__, id); 3304 return 0; 3305 } 3306 if (channel_proxy_upstream(c, type, seq, ssh)) 3307 return 0; 3308 if (sshpkt_get_end(ssh) != 0) 3309 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3310 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3311 return 0; 3312 cc->cb(ssh, type, c, cc->ctx); 3313 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3314 freezero(cc, sizeof(*cc)); 3315 return 0; 3316 } 3317 3318 /* -- tcp forwarding */ 3319 3320 void 3321 channel_set_af(struct ssh *ssh, int af) 3322 { 3323 ssh->chanctxt->IPv4or6 = af; 3324 } 3325 3326 void 3327 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size) 3328 { 3329 hpn_disabled = external_hpn_disabled; 3330 hpn_buffer_size = external_hpn_buffer_size; 3331 debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size); 3332 } 3333 3334 /* 3335 * Determine whether or not a port forward listens to loopback, the 3336 * specified address or wildcard. On the client, a specified bind 3337 * address will always override gateway_ports. On the server, a 3338 * gateway_ports of 1 (``yes'') will override the client's specification 3339 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3340 * will bind to whatever address the client asked for. 3341 * 3342 * Special-case listen_addrs are: 3343 * 3344 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3345 * "" (empty string), "*" -> wildcard v4/v6 3346 * "localhost" -> loopback v4/v6 3347 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3348 */ 3349 static const char * 3350 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3351 int is_client, struct ForwardOptions *fwd_opts) 3352 { 3353 const char *addr = NULL; 3354 int wildcard = 0; 3355 3356 if (listen_addr == NULL) { 3357 /* No address specified: default to gateway_ports setting */ 3358 if (fwd_opts->gateway_ports) 3359 wildcard = 1; 3360 } else if (fwd_opts->gateway_ports || is_client) { 3361 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 3362 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3363 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3364 (!is_client && fwd_opts->gateway_ports == 1)) { 3365 wildcard = 1; 3366 /* 3367 * Notify client if they requested a specific listen 3368 * address and it was overridden. 3369 */ 3370 if (*listen_addr != '\0' && 3371 strcmp(listen_addr, "0.0.0.0") != 0 && 3372 strcmp(listen_addr, "*") != 0) { 3373 ssh_packet_send_debug(ssh, 3374 "Forwarding listen address " 3375 "\"%s\" overridden by server " 3376 "GatewayPorts", listen_addr); 3377 } 3378 } else if (strcmp(listen_addr, "localhost") != 0 || 3379 strcmp(listen_addr, "127.0.0.1") == 0 || 3380 strcmp(listen_addr, "::1") == 0) { 3381 /* 3382 * Accept explicit localhost address when 3383 * GatewayPorts=yes. The "localhost" hostname is 3384 * deliberately skipped here so it will listen on all 3385 * available local address families. 3386 */ 3387 addr = listen_addr; 3388 } 3389 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3390 strcmp(listen_addr, "::1") == 0) { 3391 /* 3392 * If a specific IPv4/IPv6 localhost address has been 3393 * requested then accept it even if gateway_ports is in 3394 * effect. This allows the client to prefer IPv4 or IPv6. 3395 */ 3396 addr = listen_addr; 3397 } 3398 if (wildcardp != NULL) 3399 *wildcardp = wildcard; 3400 return addr; 3401 } 3402 3403 static int 3404 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3405 struct Forward *fwd, int *allocated_listen_port, 3406 struct ForwardOptions *fwd_opts) 3407 { 3408 Channel *c; 3409 int sock, r, success = 0, wildcard = 0, is_client; 3410 struct addrinfo hints, *ai, *aitop; 3411 const char *host, *addr; 3412 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3413 in_port_t *lport_p; 3414 3415 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3416 3417 if (is_client && fwd->connect_path != NULL) { 3418 host = fwd->connect_path; 3419 } else { 3420 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3421 fwd->listen_host : fwd->connect_host; 3422 if (host == NULL) { 3423 error("No forward host name."); 3424 return 0; 3425 } 3426 if (strlen(host) >= NI_MAXHOST) { 3427 error("Forward host name too long."); 3428 return 0; 3429 } 3430 } 3431 3432 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3433 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3434 is_client, fwd_opts); 3435 debug3("%s: type %d wildcard %d addr %s", __func__, 3436 type, wildcard, (addr == NULL) ? "NULL" : addr); 3437 3438 /* 3439 * getaddrinfo returns a loopback address if the hostname is 3440 * set to NULL and hints.ai_flags is not AI_PASSIVE 3441 */ 3442 memset(&hints, 0, sizeof(hints)); 3443 hints.ai_family = ssh->chanctxt->IPv4or6; 3444 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3445 hints.ai_socktype = SOCK_STREAM; 3446 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3447 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3448 if (addr == NULL) { 3449 /* This really shouldn't happen */ 3450 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3451 ssh_gai_strerror(r)); 3452 } else { 3453 error("%s: getaddrinfo(%.64s): %s", __func__, addr, 3454 ssh_gai_strerror(r)); 3455 } 3456 return 0; 3457 } 3458 if (allocated_listen_port != NULL) 3459 *allocated_listen_port = 0; 3460 for (ai = aitop; ai; ai = ai->ai_next) { 3461 switch (ai->ai_family) { 3462 case AF_INET: 3463 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3464 sin_port; 3465 break; 3466 case AF_INET6: 3467 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3468 sin6_port; 3469 break; 3470 default: 3471 continue; 3472 } 3473 /* 3474 * If allocating a port for -R forwards, then use the 3475 * same port for all address families. 3476 */ 3477 if (type == SSH_CHANNEL_RPORT_LISTENER && 3478 fwd->listen_port == 0 && allocated_listen_port != NULL && 3479 *allocated_listen_port > 0) 3480 *lport_p = htons(*allocated_listen_port); 3481 3482 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3483 strport, sizeof(strport), 3484 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3485 error("%s: getnameinfo failed", __func__); 3486 continue; 3487 } 3488 /* Create a port to listen for the host. */ 3489 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3490 if (sock == -1) { 3491 /* this is no error since kernel may not support ipv6 */ 3492 verbose("socket [%s]:%s: %.100s", ntop, strport, 3493 strerror(errno)); 3494 continue; 3495 } 3496 3497 set_reuseaddr(sock); 3498 3499 debug("Local forwarding listening on %s port %s.", 3500 ntop, strport); 3501 3502 /* Bind the socket to the address. */ 3503 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3504 /* 3505 * address can be in if use ipv6 address is 3506 * already bound 3507 */ 3508 verbose("bind [%s]:%s: %.100s", 3509 ntop, strport, strerror(errno)); 3510 close(sock); 3511 continue; 3512 } 3513 /* Start listening for connections on the socket. */ 3514 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3515 error("listen [%s]:%s: %.100s", ntop, strport, 3516 strerror(errno)); 3517 close(sock); 3518 continue; 3519 } 3520 3521 /* 3522 * fwd->listen_port == 0 requests a dynamically allocated port - 3523 * record what we got. 3524 */ 3525 if (type == SSH_CHANNEL_RPORT_LISTENER && 3526 fwd->listen_port == 0 && 3527 allocated_listen_port != NULL && 3528 *allocated_listen_port == 0) { 3529 *allocated_listen_port = get_local_port(sock); 3530 debug("Allocated listen port %d", 3531 *allocated_listen_port); 3532 } 3533 3534 /* Allocate a channel number for the socket. */ 3535 /* explicitly test for hpn disabled option. if true use smaller window size */ 3536 if (hpn_disabled) 3537 c = channel_new(ssh, "port listener", type, sock, sock, -1, 3538 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3539 0, "port listener", 1); 3540 else 3541 c = channel_new(ssh, "port listener", type, sock, sock, 3542 -1, hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 3543 0, "port listener", 1); 3544 c->path = xstrdup(host); 3545 c->host_port = fwd->connect_port; 3546 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3547 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3548 !(datafellows & SSH_BUG_DYNAMIC_RPORT)) 3549 c->listening_port = *allocated_listen_port; 3550 else 3551 c->listening_port = fwd->listen_port; 3552 success = 1; 3553 } 3554 if (success == 0) 3555 error("%s: cannot listen to port: %d", __func__, 3556 fwd->listen_port); 3557 freeaddrinfo(aitop); 3558 return success; 3559 } 3560 3561 static int 3562 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3563 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3564 { 3565 struct sockaddr_un sunaddr; 3566 const char *path; 3567 Channel *c; 3568 int port, sock; 3569 mode_t omask; 3570 3571 switch (type) { 3572 case SSH_CHANNEL_UNIX_LISTENER: 3573 if (fwd->connect_path != NULL) { 3574 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3575 error("Local connecting path too long: %s", 3576 fwd->connect_path); 3577 return 0; 3578 } 3579 path = fwd->connect_path; 3580 port = PORT_STREAMLOCAL; 3581 } else { 3582 if (fwd->connect_host == NULL) { 3583 error("No forward host name."); 3584 return 0; 3585 } 3586 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3587 error("Forward host name too long."); 3588 return 0; 3589 } 3590 path = fwd->connect_host; 3591 port = fwd->connect_port; 3592 } 3593 break; 3594 case SSH_CHANNEL_RUNIX_LISTENER: 3595 path = fwd->listen_path; 3596 port = PORT_STREAMLOCAL; 3597 break; 3598 default: 3599 error("%s: unexpected channel type %d", __func__, type); 3600 return 0; 3601 } 3602 3603 if (fwd->listen_path == NULL) { 3604 error("No forward path name."); 3605 return 0; 3606 } 3607 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3608 error("Local listening path too long: %s", fwd->listen_path); 3609 return 0; 3610 } 3611 3612 debug3("%s: type %d path %s", __func__, type, fwd->listen_path); 3613 3614 /* Start a Unix domain listener. */ 3615 omask = umask(fwd_opts->streamlocal_bind_mask); 3616 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3617 fwd_opts->streamlocal_bind_unlink); 3618 umask(omask); 3619 if (sock < 0) 3620 return 0; 3621 3622 debug("Local forwarding listening on path %s.", fwd->listen_path); 3623 3624 /* Allocate a channel number for the socket. */ 3625 c = channel_new(ssh, "unix listener", type, sock, sock, -1, 3626 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3627 0, "unix listener", 1); 3628 c->path = xstrdup(path); 3629 c->host_port = port; 3630 c->listening_port = PORT_STREAMLOCAL; 3631 c->listening_addr = xstrdup(fwd->listen_path); 3632 return 1; 3633 } 3634 3635 static int 3636 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3637 const char *host, u_short port) 3638 { 3639 u_int i; 3640 int found = 0; 3641 3642 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3643 Channel *c = ssh->chanctxt->channels[i]; 3644 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3645 continue; 3646 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3647 debug2("%s: close channel %d", __func__, i); 3648 channel_free(ssh, c); 3649 found = 1; 3650 } 3651 } 3652 3653 return found; 3654 } 3655 3656 static int 3657 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3658 { 3659 u_int i; 3660 int found = 0; 3661 3662 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3663 Channel *c = ssh->chanctxt->channels[i]; 3664 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3665 continue; 3666 if (c->path == NULL) 3667 continue; 3668 if (strcmp(c->path, path) == 0) { 3669 debug2("%s: close channel %d", __func__, i); 3670 channel_free(ssh, c); 3671 found = 1; 3672 } 3673 } 3674 3675 return found; 3676 } 3677 3678 int 3679 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3680 { 3681 if (fwd->listen_path != NULL) { 3682 return channel_cancel_rport_listener_streamlocal(ssh, 3683 fwd->listen_path); 3684 } else { 3685 return channel_cancel_rport_listener_tcpip(ssh, 3686 fwd->listen_host, fwd->listen_port); 3687 } 3688 } 3689 3690 static int 3691 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 3692 const char *lhost, u_short lport, int cport, 3693 struct ForwardOptions *fwd_opts) 3694 { 3695 u_int i; 3696 int found = 0; 3697 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 3698 3699 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3700 Channel *c = ssh->chanctxt->channels[i]; 3701 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 3702 continue; 3703 if (c->listening_port != lport) 3704 continue; 3705 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 3706 /* skip dynamic forwardings */ 3707 if (c->host_port == 0) 3708 continue; 3709 } else { 3710 if (c->host_port != cport) 3711 continue; 3712 } 3713 if ((c->listening_addr == NULL && addr != NULL) || 3714 (c->listening_addr != NULL && addr == NULL)) 3715 continue; 3716 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 3717 debug2("%s: close channel %d", __func__, i); 3718 channel_free(ssh, c); 3719 found = 1; 3720 } 3721 } 3722 3723 return found; 3724 } 3725 3726 static int 3727 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 3728 { 3729 u_int i; 3730 int found = 0; 3731 3732 if (path == NULL) { 3733 error("%s: no path specified.", __func__); 3734 return 0; 3735 } 3736 3737 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3738 Channel *c = ssh->chanctxt->channels[i]; 3739 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 3740 continue; 3741 if (c->listening_addr == NULL) 3742 continue; 3743 if (strcmp(c->listening_addr, path) == 0) { 3744 debug2("%s: close channel %d", __func__, i); 3745 channel_free(ssh, c); 3746 found = 1; 3747 } 3748 } 3749 3750 return found; 3751 } 3752 3753 int 3754 channel_cancel_lport_listener(struct ssh *ssh, 3755 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 3756 { 3757 if (fwd->listen_path != NULL) { 3758 return channel_cancel_lport_listener_streamlocal(ssh, 3759 fwd->listen_path); 3760 } else { 3761 return channel_cancel_lport_listener_tcpip(ssh, 3762 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 3763 } 3764 } 3765 3766 /* protocol local port fwd, used by ssh */ 3767 int 3768 channel_setup_local_fwd_listener(struct ssh *ssh, 3769 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3770 { 3771 if (fwd->listen_path != NULL) { 3772 return channel_setup_fwd_listener_streamlocal(ssh, 3773 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 3774 } else { 3775 return channel_setup_fwd_listener_tcpip(ssh, 3776 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 3777 } 3778 } 3779 3780 /* Matches a remote forwarding permission against a requested forwarding */ 3781 static int 3782 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 3783 { 3784 int ret; 3785 char *lhost; 3786 3787 /* XXX add ACLs for streamlocal */ 3788 if (fwd->listen_path != NULL) 3789 return 1; 3790 3791 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 3792 return 0; 3793 3794 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 3795 allowed_open->listen_port != fwd->listen_port) 3796 return 0; 3797 3798 /* Match hostnames case-insensitively */ 3799 lhost = xstrdup(fwd->listen_host); 3800 lowercase(lhost); 3801 ret = match_pattern(lhost, allowed_open->listen_host); 3802 free(lhost); 3803 3804 return ret; 3805 } 3806 3807 /* Checks whether a requested remote forwarding is permitted */ 3808 static int 3809 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 3810 { 3811 struct ssh_channels *sc = ssh->chanctxt; 3812 struct permission_set *pset = &sc->remote_perms; 3813 u_int i, permit, permit_adm = 1; 3814 struct permission *perm; 3815 3816 /* XXX apply GatewayPorts override before checking? */ 3817 3818 permit = pset->all_permitted; 3819 if (!permit) { 3820 for (i = 0; i < pset->num_permitted_user; i++) { 3821 perm = &pset->permitted_user[i]; 3822 if (remote_open_match(perm, fwd)) { 3823 permit = 1; 3824 break; 3825 } 3826 } 3827 } 3828 3829 if (pset->num_permitted_admin > 0) { 3830 permit_adm = 0; 3831 for (i = 0; i < pset->num_permitted_admin; i++) { 3832 perm = &pset->permitted_admin[i]; 3833 if (remote_open_match(perm, fwd)) { 3834 permit_adm = 1; 3835 break; 3836 } 3837 } 3838 } 3839 3840 return permit && permit_adm; 3841 } 3842 3843 /* protocol v2 remote port fwd, used by sshd */ 3844 int 3845 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 3846 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 3847 { 3848 if (!check_rfwd_permission(ssh, fwd)) { 3849 ssh_packet_send_debug(ssh, "port forwarding refused"); 3850 if (fwd->listen_path != NULL) 3851 /* XXX always allowed, see remote_open_match() */ 3852 logit("Received request from %.100s port %d to " 3853 "remote forward to path \"%.100s\", " 3854 "but the request was denied.", 3855 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 3856 fwd->listen_path); 3857 else if(fwd->listen_host != NULL) 3858 logit("Received request from %.100s port %d to " 3859 "remote forward to host %.100s port %d, " 3860 "but the request was denied.", 3861 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 3862 fwd->listen_host, fwd->listen_port ); 3863 else 3864 logit("Received request from %.100s port %d to remote " 3865 "forward, but the request was denied.", 3866 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 3867 return 0; 3868 } 3869 if (fwd->listen_path != NULL) { 3870 return channel_setup_fwd_listener_streamlocal(ssh, 3871 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 3872 } else { 3873 return channel_setup_fwd_listener_tcpip(ssh, 3874 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 3875 fwd_opts); 3876 } 3877 } 3878 3879 /* 3880 * Translate the requested rfwd listen host to something usable for 3881 * this server. 3882 */ 3883 static const char * 3884 channel_rfwd_bind_host(const char *listen_host) 3885 { 3886 if (listen_host == NULL) { 3887 return "localhost"; 3888 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 3889 return ""; 3890 } else 3891 return listen_host; 3892 } 3893 3894 /* 3895 * Initiate forwarding of connections to port "port" on remote host through 3896 * the secure channel to host:port from local side. 3897 * Returns handle (index) for updating the dynamic listen port with 3898 * channel_update_permission(). 3899 */ 3900 int 3901 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 3902 { 3903 int r, success = 0, idx = -1; 3904 char *host_to_connect, *listen_host, *listen_path; 3905 int port_to_connect, listen_port; 3906 3907 /* Send the forward request to the remote side. */ 3908 if (fwd->listen_path != NULL) { 3909 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3910 (r = sshpkt_put_cstring(ssh, 3911 "streamlocal-forward@openssh.com")) != 0 || 3912 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 3913 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 3914 (r = sshpkt_send(ssh)) != 0 || 3915 (r = ssh_packet_write_wait(ssh)) < 0) 3916 fatal("%s: request streamlocal: %s", 3917 __func__, ssh_err(r)); 3918 } else { 3919 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3920 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 3921 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 3922 (r = sshpkt_put_cstring(ssh, 3923 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 3924 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 3925 (r = sshpkt_send(ssh)) != 0 || 3926 (r = ssh_packet_write_wait(ssh)) < 0) 3927 fatal("%s: request tcpip-forward: %s", 3928 __func__, ssh_err(r)); 3929 } 3930 /* Assume that server accepts the request */ 3931 success = 1; 3932 if (success) { 3933 /* Record that connection to this host/port is permitted. */ 3934 host_to_connect = listen_host = listen_path = NULL; 3935 port_to_connect = listen_port = 0; 3936 if (fwd->connect_path != NULL) { 3937 host_to_connect = xstrdup(fwd->connect_path); 3938 port_to_connect = PORT_STREAMLOCAL; 3939 } else { 3940 host_to_connect = xstrdup(fwd->connect_host); 3941 port_to_connect = fwd->connect_port; 3942 } 3943 if (fwd->listen_path != NULL) { 3944 listen_path = xstrdup(fwd->listen_path); 3945 listen_port = PORT_STREAMLOCAL; 3946 } else { 3947 if (fwd->listen_host != NULL) 3948 listen_host = xstrdup(fwd->listen_host); 3949 listen_port = fwd->listen_port; 3950 } 3951 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 3952 host_to_connect, port_to_connect, 3953 listen_host, listen_path, listen_port, NULL); 3954 } 3955 return idx; 3956 } 3957 3958 static int 3959 open_match(struct permission *allowed_open, const char *requestedhost, 3960 int requestedport) 3961 { 3962 if (allowed_open->host_to_connect == NULL) 3963 return 0; 3964 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 3965 allowed_open->port_to_connect != requestedport) 3966 return 0; 3967 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 3968 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 3969 return 0; 3970 return 1; 3971 } 3972 3973 /* 3974 * Note that in the listen host/port case 3975 * we don't support FWD_PERMIT_ANY_PORT and 3976 * need to translate between the configured-host (listen_host) 3977 * and what we've sent to the remote server (channel_rfwd_bind_host) 3978 */ 3979 static int 3980 open_listen_match_tcpip(struct permission *allowed_open, 3981 const char *requestedhost, u_short requestedport, int translate) 3982 { 3983 const char *allowed_host; 3984 3985 if (allowed_open->host_to_connect == NULL) 3986 return 0; 3987 if (allowed_open->listen_port != requestedport) 3988 return 0; 3989 if (!translate && allowed_open->listen_host == NULL && 3990 requestedhost == NULL) 3991 return 1; 3992 allowed_host = translate ? 3993 channel_rfwd_bind_host(allowed_open->listen_host) : 3994 allowed_open->listen_host; 3995 if (allowed_host == NULL || requestedhost == NULL || 3996 strcmp(allowed_host, requestedhost) != 0) 3997 return 0; 3998 return 1; 3999 } 4000 4001 static int 4002 open_listen_match_streamlocal(struct permission *allowed_open, 4003 const char *requestedpath) 4004 { 4005 if (allowed_open->host_to_connect == NULL) 4006 return 0; 4007 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4008 return 0; 4009 if (allowed_open->listen_path == NULL || 4010 strcmp(allowed_open->listen_path, requestedpath) != 0) 4011 return 0; 4012 return 1; 4013 } 4014 4015 /* 4016 * Request cancellation of remote forwarding of connection host:port from 4017 * local side. 4018 */ 4019 static int 4020 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4021 const char *host, u_short port) 4022 { 4023 struct ssh_channels *sc = ssh->chanctxt; 4024 struct permission_set *pset = &sc->local_perms; 4025 int r; 4026 u_int i; 4027 struct permission *perm = NULL; 4028 4029 for (i = 0; i < pset->num_permitted_user; i++) { 4030 perm = &pset->permitted_user[i]; 4031 if (open_listen_match_tcpip(perm, host, port, 0)) 4032 break; 4033 perm = NULL; 4034 } 4035 if (perm == NULL) { 4036 debug("%s: requested forward not found", __func__); 4037 return -1; 4038 } 4039 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4040 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4041 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4042 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4043 (r = sshpkt_put_u32(ssh, port)) != 0 || 4044 (r = sshpkt_send(ssh)) != 0) 4045 fatal("%s: send cancel: %s", __func__, ssh_err(r)); 4046 4047 fwd_perm_clear(perm); /* unregister */ 4048 4049 return 0; 4050 } 4051 4052 /* 4053 * Request cancellation of remote forwarding of Unix domain socket 4054 * path from local side. 4055 */ 4056 static int 4057 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4058 { 4059 struct ssh_channels *sc = ssh->chanctxt; 4060 struct permission_set *pset = &sc->local_perms; 4061 int r; 4062 u_int i; 4063 struct permission *perm = NULL; 4064 4065 for (i = 0; i < pset->num_permitted_user; i++) { 4066 perm = &pset->permitted_user[i]; 4067 if (open_listen_match_streamlocal(perm, path)) 4068 break; 4069 perm = NULL; 4070 } 4071 if (perm == NULL) { 4072 debug("%s: requested forward not found", __func__); 4073 return -1; 4074 } 4075 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4076 (r = sshpkt_put_cstring(ssh, 4077 "cancel-streamlocal-forward@openssh.com")) != 0 || 4078 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4079 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4080 (r = sshpkt_send(ssh)) != 0) 4081 fatal("%s: send cancel: %s", __func__, ssh_err(r)); 4082 4083 fwd_perm_clear(perm); /* unregister */ 4084 4085 return 0; 4086 } 4087 4088 /* 4089 * Request cancellation of remote forwarding of a connection from local side. 4090 */ 4091 int 4092 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4093 { 4094 if (fwd->listen_path != NULL) { 4095 return channel_request_rforward_cancel_streamlocal(ssh, 4096 fwd->listen_path); 4097 } else { 4098 return channel_request_rforward_cancel_tcpip(ssh, 4099 fwd->listen_host, 4100 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4101 } 4102 } 4103 4104 /* 4105 * Permits opening to any host/port if permitted_user[] is empty. This is 4106 * usually called by the server, because the user could connect to any port 4107 * anyway, and the server has no way to know but to trust the client anyway. 4108 */ 4109 void 4110 channel_permit_all(struct ssh *ssh, int where) 4111 { 4112 struct permission_set *pset = permission_set_get(ssh, where); 4113 4114 if (pset->num_permitted_user == 0) 4115 pset->all_permitted = 1; 4116 } 4117 4118 /* 4119 * Permit the specified host/port for forwarding. 4120 */ 4121 void 4122 channel_add_permission(struct ssh *ssh, int who, int where, 4123 char *host, int port) 4124 { 4125 int local = where == FORWARD_LOCAL; 4126 struct permission_set *pset = permission_set_get(ssh, where); 4127 4128 debug("allow %s forwarding to host %s port %d", 4129 fwd_ident(who, where), host, port); 4130 /* 4131 * Remote forwards set listen_host/port, local forwards set 4132 * host/port_to_connect. 4133 */ 4134 permission_set_add(ssh, who, where, 4135 local ? host : 0, local ? port : 0, 4136 local ? NULL : host, NULL, local ? 0 : port, NULL); 4137 pset->all_permitted = 0; 4138 } 4139 4140 /* 4141 * Administratively disable forwarding. 4142 */ 4143 void 4144 channel_disable_admin(struct ssh *ssh, int where) 4145 { 4146 channel_clear_permission(ssh, FORWARD_ADM, where); 4147 permission_set_add(ssh, FORWARD_ADM, where, 4148 NULL, 0, NULL, NULL, 0, NULL); 4149 } 4150 4151 /* 4152 * Clear a list of permitted opens. 4153 */ 4154 void 4155 channel_clear_permission(struct ssh *ssh, int who, int where) 4156 { 4157 struct permission **permp; 4158 u_int *npermp; 4159 4160 permission_set_get_array(ssh, who, where, &permp, &npermp); 4161 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4162 *npermp = 0; 4163 } 4164 4165 /* 4166 * Update the listen port for a dynamic remote forward, after 4167 * the actual 'newport' has been allocated. If 'newport' < 0 is 4168 * passed then they entry will be invalidated. 4169 */ 4170 void 4171 channel_update_permission(struct ssh *ssh, int idx, int newport) 4172 { 4173 struct permission_set *pset = &ssh->chanctxt->local_perms; 4174 4175 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4176 debug("%s: index out of range: %d num_permitted_user %d", 4177 __func__, idx, pset->num_permitted_user); 4178 return; 4179 } 4180 debug("%s allowed port %d for forwarding to host %s port %d", 4181 newport > 0 ? "Updating" : "Removing", 4182 newport, 4183 pset->permitted_user[idx].host_to_connect, 4184 pset->permitted_user[idx].port_to_connect); 4185 if (newport <= 0) 4186 fwd_perm_clear(&pset->permitted_user[idx]); 4187 else { 4188 pset->permitted_user[idx].listen_port = 4189 (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4190 } 4191 } 4192 4193 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4194 int 4195 permitopen_port(const char *p) 4196 { 4197 int port; 4198 4199 if (strcmp(p, "*") == 0) 4200 return FWD_PERMIT_ANY_PORT; 4201 if ((port = a2port(p)) > 0) 4202 return port; 4203 return -1; 4204 } 4205 4206 /* Try to start non-blocking connect to next host in cctx list */ 4207 static int 4208 connect_next(struct channel_connect *cctx) 4209 { 4210 int sock, saved_errno; 4211 struct sockaddr_un *sunaddr; 4212 char ntop[NI_MAXHOST]; 4213 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4214 4215 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4216 switch (cctx->ai->ai_family) { 4217 case AF_UNIX: 4218 /* unix:pathname instead of host:port */ 4219 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4220 strlcpy(ntop, "unix", sizeof(ntop)); 4221 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4222 break; 4223 case AF_INET: 4224 case AF_INET6: 4225 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4226 ntop, sizeof(ntop), strport, sizeof(strport), 4227 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4228 error("connect_next: getnameinfo failed"); 4229 continue; 4230 } 4231 break; 4232 default: 4233 continue; 4234 } 4235 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4236 cctx->ai->ai_protocol)) == -1) { 4237 if (cctx->ai->ai_next == NULL) 4238 error("socket: %.100s", strerror(errno)); 4239 else 4240 verbose("socket: %.100s", strerror(errno)); 4241 continue; 4242 } 4243 if (set_nonblock(sock) == -1) 4244 fatal("%s: set_nonblock(%d)", __func__, sock); 4245 if (connect(sock, cctx->ai->ai_addr, 4246 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4247 debug("connect_next: host %.100s ([%.100s]:%s): " 4248 "%.100s", cctx->host, ntop, strport, 4249 strerror(errno)); 4250 saved_errno = errno; 4251 close(sock); 4252 errno = saved_errno; 4253 continue; /* fail -- try next */ 4254 } 4255 if (cctx->ai->ai_family != AF_UNIX) 4256 set_nodelay(sock); 4257 debug("connect_next: host %.100s ([%.100s]:%s) " 4258 "in progress, fd=%d", cctx->host, ntop, strport, sock); 4259 cctx->ai = cctx->ai->ai_next; 4260 return sock; 4261 } 4262 return -1; 4263 } 4264 4265 static void 4266 channel_connect_ctx_free(struct channel_connect *cctx) 4267 { 4268 free(cctx->host); 4269 if (cctx->aitop) { 4270 if (cctx->aitop->ai_family == AF_UNIX) 4271 free(cctx->aitop); 4272 else 4273 freeaddrinfo(cctx->aitop); 4274 } 4275 memset(cctx, 0, sizeof(*cctx)); 4276 } 4277 4278 /* 4279 * Return connecting socket to remote host:port or local socket path, 4280 * passing back the failure reason if appropriate. 4281 */ 4282 static int 4283 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4284 const char *ctype, const char *rname, struct channel_connect *cctx, 4285 int *reason, const char **errmsg) 4286 { 4287 struct addrinfo hints; 4288 int gaierr; 4289 int sock = -1; 4290 char strport[NI_MAXSERV]; 4291 4292 if (port == PORT_STREAMLOCAL) { 4293 struct sockaddr_un *sunaddr; 4294 struct addrinfo *ai; 4295 4296 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4297 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4298 return -1; 4299 } 4300 4301 /* 4302 * Fake up a struct addrinfo for AF_UNIX connections. 4303 * channel_connect_ctx_free() must check ai_family 4304 * and use free() not freeaddirinfo() for AF_UNIX. 4305 */ 4306 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4307 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4308 ai->ai_addr = (struct sockaddr *)(ai + 1); 4309 ai->ai_addrlen = sizeof(*sunaddr); 4310 ai->ai_family = AF_UNIX; 4311 ai->ai_socktype = socktype; 4312 ai->ai_protocol = PF_UNSPEC; 4313 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4314 sunaddr->sun_family = AF_UNIX; 4315 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4316 cctx->aitop = ai; 4317 } else { 4318 memset(&hints, 0, sizeof(hints)); 4319 hints.ai_family = ssh->chanctxt->IPv4or6; 4320 hints.ai_socktype = socktype; 4321 snprintf(strport, sizeof strport, "%d", port); 4322 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4323 != 0) { 4324 if (errmsg != NULL) 4325 *errmsg = ssh_gai_strerror(gaierr); 4326 if (reason != NULL) 4327 *reason = SSH2_OPEN_CONNECT_FAILED; 4328 error("connect_to %.100s: unknown host (%s)", name, 4329 ssh_gai_strerror(gaierr)); 4330 return -1; 4331 } 4332 } 4333 4334 cctx->host = xstrdup(name); 4335 cctx->port = port; 4336 cctx->ai = cctx->aitop; 4337 4338 if ((sock = connect_next(cctx)) == -1) { 4339 error("connect to %.100s port %d failed: %s", 4340 name, port, strerror(errno)); 4341 return -1; 4342 } 4343 4344 return sock; 4345 } 4346 4347 /* Return CONNECTING channel to remote host:port or local socket path */ 4348 static Channel * 4349 connect_to(struct ssh *ssh, const char *host, int port, 4350 const char *ctype, const char *rname) 4351 { 4352 struct channel_connect cctx; 4353 Channel *c; 4354 int sock; 4355 4356 memset(&cctx, 0, sizeof(cctx)); 4357 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4358 &cctx, NULL, NULL); 4359 if (sock == -1) { 4360 channel_connect_ctx_free(&cctx); 4361 return NULL; 4362 } 4363 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4364 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4365 c->host_port = port; 4366 c->path = xstrdup(host); 4367 c->connect_ctx = cctx; 4368 4369 return c; 4370 } 4371 4372 /* 4373 * returns either the newly connected channel or the downstream channel 4374 * that needs to deal with this connection. 4375 */ 4376 Channel * 4377 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4378 u_short listen_port, const char *ctype, const char *rname) 4379 { 4380 struct ssh_channels *sc = ssh->chanctxt; 4381 struct permission_set *pset = &sc->local_perms; 4382 u_int i; 4383 struct permission *perm; 4384 4385 for (i = 0; i < pset->num_permitted_user; i++) { 4386 perm = &pset->permitted_user[i]; 4387 if (open_listen_match_tcpip(perm, 4388 listen_host, listen_port, 1)) { 4389 if (perm->downstream) 4390 return perm->downstream; 4391 if (perm->port_to_connect == 0) 4392 return rdynamic_connect_prepare(ssh, 4393 ctype, rname); 4394 return connect_to(ssh, 4395 perm->host_to_connect, perm->port_to_connect, 4396 ctype, rname); 4397 } 4398 } 4399 error("WARNING: Server requests forwarding for unknown listen_port %d", 4400 listen_port); 4401 return NULL; 4402 } 4403 4404 Channel * 4405 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4406 const char *ctype, const char *rname) 4407 { 4408 struct ssh_channels *sc = ssh->chanctxt; 4409 struct permission_set *pset = &sc->local_perms; 4410 u_int i; 4411 struct permission *perm; 4412 4413 for (i = 0; i < pset->num_permitted_user; i++) { 4414 perm = &pset->permitted_user[i]; 4415 if (open_listen_match_streamlocal(perm, path)) { 4416 return connect_to(ssh, 4417 perm->host_to_connect, perm->port_to_connect, 4418 ctype, rname); 4419 } 4420 } 4421 error("WARNING: Server requests forwarding for unknown path %.100s", 4422 path); 4423 return NULL; 4424 } 4425 4426 /* Check if connecting to that port is permitted and connect. */ 4427 Channel * 4428 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4429 const char *ctype, const char *rname, int *reason, const char **errmsg) 4430 { 4431 struct ssh_channels *sc = ssh->chanctxt; 4432 struct permission_set *pset = &sc->local_perms; 4433 struct channel_connect cctx; 4434 Channel *c; 4435 u_int i, permit, permit_adm = 1; 4436 int sock; 4437 struct permission *perm; 4438 4439 permit = pset->all_permitted; 4440 if (!permit) { 4441 for (i = 0; i < pset->num_permitted_user; i++) { 4442 perm = &pset->permitted_user[i]; 4443 if (open_match(perm, host, port)) { 4444 permit = 1; 4445 break; 4446 } 4447 } 4448 } 4449 4450 if (pset->num_permitted_admin > 0) { 4451 permit_adm = 0; 4452 for (i = 0; i < pset->num_permitted_admin; i++) { 4453 perm = &pset->permitted_admin[i]; 4454 if (open_match(perm, host, port)) { 4455 permit_adm = 1; 4456 break; 4457 } 4458 } 4459 } 4460 4461 if (!permit || !permit_adm) { 4462 logit("Received request from %.100s port %d to connect to " 4463 "host %.100s port %d, but the request was denied.", 4464 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4465 if (reason != NULL) 4466 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4467 return NULL; 4468 } 4469 4470 memset(&cctx, 0, sizeof(cctx)); 4471 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4472 &cctx, reason, errmsg); 4473 if (sock == -1) { 4474 channel_connect_ctx_free(&cctx); 4475 return NULL; 4476 } 4477 4478 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4479 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4480 c->host_port = port; 4481 c->path = xstrdup(host); 4482 c->connect_ctx = cctx; 4483 4484 return c; 4485 } 4486 4487 /* Check if connecting to that path is permitted and connect. */ 4488 Channel * 4489 channel_connect_to_path(struct ssh *ssh, const char *path, const char *ctype, 4490 const char *rname) 4491 { 4492 struct ssh_channels *sc = ssh->chanctxt; 4493 struct permission_set *pset = &sc->local_perms; 4494 u_int i, permit, permit_adm = 1; 4495 struct permission *perm; 4496 4497 permit = pset->all_permitted; 4498 if (!permit) { 4499 for (i = 0; i < pset->num_permitted_user; i++) { 4500 perm = &pset->permitted_user[i]; 4501 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4502 permit = 1; 4503 break; 4504 } 4505 } 4506 } 4507 4508 if (pset->num_permitted_admin > 0) { 4509 permit_adm = 0; 4510 for (i = 0; i < pset->num_permitted_admin; i++) { 4511 perm = &pset->permitted_admin[i]; 4512 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4513 permit_adm = 1; 4514 break; 4515 } 4516 } 4517 } 4518 4519 if (!permit || !permit_adm) { 4520 logit("Received request to connect to path %.100s, " 4521 "but the request was denied.", path); 4522 return NULL; 4523 } 4524 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4525 } 4526 4527 void 4528 channel_send_window_changes(struct ssh *ssh) 4529 { 4530 struct ssh_channels *sc = ssh->chanctxt; 4531 struct winsize ws; 4532 int r; 4533 u_int i; 4534 4535 for (i = 0; i < sc->channels_alloc; i++) { 4536 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4537 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4538 continue; 4539 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4540 continue; 4541 channel_request_start(ssh, i, "window-change", 0); 4542 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4543 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4544 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4545 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4546 (r = sshpkt_send(ssh)) != 0) 4547 fatal("%s: channel %u: send window-change: %s", 4548 __func__, i, ssh_err(r)); 4549 } 4550 } 4551 4552 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4553 static Channel * 4554 rdynamic_connect_prepare(struct ssh *ssh, const char *ctype, const char *rname) 4555 { 4556 Channel *c; 4557 int r; 4558 4559 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4560 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4561 c->host_port = 0; 4562 c->path = NULL; 4563 4564 /* 4565 * We need to open the channel before we have a FD, 4566 * so that we can get SOCKS header from peer. 4567 */ 4568 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4569 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4570 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4571 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4572 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 4573 fatal("%s: channel %i: confirm: %s", __func__, 4574 c->self, ssh_err(r)); 4575 } 4576 return c; 4577 } 4578 4579 /* Return CONNECTING socket to remote host:port or local socket path */ 4580 static int 4581 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4582 { 4583 struct channel_connect cctx; 4584 int sock; 4585 4586 memset(&cctx, 0, sizeof(cctx)); 4587 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4588 NULL, &cctx, NULL, NULL); 4589 if (sock == -1) 4590 channel_connect_ctx_free(&cctx); 4591 else { 4592 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4593 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4594 c->connect_ctx = cctx; 4595 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4596 } 4597 return sock; 4598 } 4599 4600 /* -- X11 forwarding */ 4601 4602 /* 4603 * Creates an internet domain socket for listening for X11 connections. 4604 * Returns 0 and a suitable display number for the DISPLAY variable 4605 * stored in display_numberp , or -1 if an error occurs. 4606 */ 4607 int 4608 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4609 int x11_use_localhost, int single_connection, 4610 u_int *display_numberp, int **chanids) 4611 { 4612 Channel *nc = NULL; 4613 int display_number, sock; 4614 u_short port; 4615 struct addrinfo hints, *ai, *aitop; 4616 char strport[NI_MAXSERV]; 4617 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4618 4619 if (chanids == NULL) 4620 return -1; 4621 4622 for (display_number = x11_display_offset; 4623 display_number < MAX_DISPLAYS; 4624 display_number++) { 4625 port = 6000 + display_number; 4626 memset(&hints, 0, sizeof(hints)); 4627 hints.ai_family = ssh->chanctxt->IPv4or6; 4628 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4629 hints.ai_socktype = SOCK_STREAM; 4630 snprintf(strport, sizeof strport, "%d", port); 4631 if ((gaierr = getaddrinfo(NULL, strport, 4632 &hints, &aitop)) != 0) { 4633 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4634 return -1; 4635 } 4636 for (ai = aitop; ai; ai = ai->ai_next) { 4637 if (ai->ai_family != AF_INET && 4638 ai->ai_family != AF_INET6) 4639 continue; 4640 sock = socket(ai->ai_family, ai->ai_socktype, 4641 ai->ai_protocol); 4642 if (sock == -1) { 4643 error("socket: %.100s", strerror(errno)); 4644 freeaddrinfo(aitop); 4645 return -1; 4646 } 4647 set_reuseaddr(sock); 4648 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4649 debug2("%s: bind port %d: %.100s", __func__, 4650 port, strerror(errno)); 4651 close(sock); 4652 for (n = 0; n < num_socks; n++) 4653 close(socks[n]); 4654 num_socks = 0; 4655 break; 4656 } 4657 socks[num_socks++] = sock; 4658 if (num_socks == NUM_SOCKS) 4659 break; 4660 } 4661 freeaddrinfo(aitop); 4662 if (num_socks > 0) 4663 break; 4664 } 4665 if (display_number >= MAX_DISPLAYS) { 4666 error("Failed to allocate internet-domain X11 display socket."); 4667 return -1; 4668 } 4669 /* Start listening for connections on the socket. */ 4670 for (n = 0; n < num_socks; n++) { 4671 sock = socks[n]; 4672 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 4673 error("listen: %.100s", strerror(errno)); 4674 close(sock); 4675 return -1; 4676 } 4677 } 4678 4679 /* Allocate a channel for each socket. */ 4680 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 4681 for (n = 0; n < num_socks; n++) { 4682 sock = socks[n]; 4683 /* Is this really necassary? */ 4684 if (hpn_disabled) 4685 nc = channel_new(ssh, "x11 listener", 4686 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4687 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 4688 0, "X11 inet listener", 1); 4689 else 4690 nc = channel_new(ssh, "x11 listener", 4691 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4692 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 4693 0, "X11 inet listener", 1); 4694 nc->single_connection = single_connection; 4695 (*chanids)[n] = nc->self; 4696 } 4697 (*chanids)[n] = -1; 4698 4699 /* Return the display number for the DISPLAY environment variable. */ 4700 *display_numberp = display_number; 4701 return 0; 4702 } 4703 4704 static int 4705 connect_local_xsocket(u_int dnr) 4706 { 4707 int sock; 4708 struct sockaddr_un addr; 4709 4710 sock = socket(AF_UNIX, SOCK_STREAM, 0); 4711 if (sock == -1) 4712 error("socket: %.100s", strerror(errno)); 4713 memset(&addr, 0, sizeof(addr)); 4714 addr.sun_family = AF_UNIX; 4715 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 4716 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 4717 return sock; 4718 close(sock); 4719 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 4720 return -1; 4721 } 4722 4723 int 4724 x11_connect_display(struct ssh *ssh) 4725 { 4726 u_int display_number; 4727 const char *display; 4728 char buf[1024], *cp; 4729 struct addrinfo hints, *ai, *aitop; 4730 char strport[NI_MAXSERV]; 4731 int gaierr, sock = 0; 4732 4733 /* Try to open a socket for the local X server. */ 4734 display = getenv("DISPLAY"); 4735 if (!display) { 4736 error("DISPLAY not set."); 4737 return -1; 4738 } 4739 /* 4740 * Now we decode the value of the DISPLAY variable and make a 4741 * connection to the real X server. 4742 */ 4743 4744 /* 4745 * Check if it is a unix domain socket. Unix domain displays are in 4746 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 4747 */ 4748 if (strncmp(display, "unix:", 5) == 0 || 4749 display[0] == ':') { 4750 /* Connect to the unix domain socket. */ 4751 if (sscanf(strrchr(display, ':') + 1, "%u", 4752 &display_number) != 1) { 4753 error("Could not parse display number from DISPLAY: " 4754 "%.100s", display); 4755 return -1; 4756 } 4757 /* Create a socket. */ 4758 sock = connect_local_xsocket(display_number); 4759 if (sock < 0) 4760 return -1; 4761 4762 /* OK, we now have a connection to the display. */ 4763 return sock; 4764 } 4765 /* 4766 * Connect to an inet socket. The DISPLAY value is supposedly 4767 * hostname:d[.s], where hostname may also be numeric IP address. 4768 */ 4769 strlcpy(buf, display, sizeof(buf)); 4770 cp = strchr(buf, ':'); 4771 if (!cp) { 4772 error("Could not find ':' in DISPLAY: %.100s", display); 4773 return -1; 4774 } 4775 *cp = 0; 4776 /* 4777 * buf now contains the host name. But first we parse the 4778 * display number. 4779 */ 4780 if (sscanf(cp + 1, "%u", &display_number) != 1) { 4781 error("Could not parse display number from DISPLAY: %.100s", 4782 display); 4783 return -1; 4784 } 4785 4786 /* Look up the host address */ 4787 memset(&hints, 0, sizeof(hints)); 4788 hints.ai_family = ssh->chanctxt->IPv4or6; 4789 hints.ai_socktype = SOCK_STREAM; 4790 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 4791 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 4792 error("%.100s: unknown host. (%s)", buf, 4793 ssh_gai_strerror(gaierr)); 4794 return -1; 4795 } 4796 for (ai = aitop; ai; ai = ai->ai_next) { 4797 /* Create a socket. */ 4798 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 4799 if (sock == -1) { 4800 debug2("socket: %.100s", strerror(errno)); 4801 continue; 4802 } 4803 /* Connect it to the display. */ 4804 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4805 debug2("connect %.100s port %u: %.100s", buf, 4806 6000 + display_number, strerror(errno)); 4807 close(sock); 4808 continue; 4809 } 4810 /* Success */ 4811 break; 4812 } 4813 freeaddrinfo(aitop); 4814 if (!ai) { 4815 error("connect %.100s port %u: %.100s", buf, 4816 6000 + display_number, strerror(errno)); 4817 return -1; 4818 } 4819 set_nodelay(sock); 4820 return sock; 4821 } 4822 4823 /* 4824 * Requests forwarding of X11 connections, generates fake authentication 4825 * data, and enables authentication spoofing. 4826 * This should be called in the client only. 4827 */ 4828 void 4829 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 4830 const char *disp, const char *proto, const char *data, int want_reply) 4831 { 4832 struct ssh_channels *sc = ssh->chanctxt; 4833 u_int data_len = (u_int) strlen(data) / 2; 4834 u_int i, value; 4835 const char *cp; 4836 char *new_data; 4837 int r, screen_number; 4838 4839 if (sc->x11_saved_display == NULL) 4840 sc->x11_saved_display = xstrdup(disp); 4841 else if (strcmp(disp, sc->x11_saved_display) != 0) { 4842 error("x11_request_forwarding_with_spoofing: different " 4843 "$DISPLAY already forwarded"); 4844 return; 4845 } 4846 4847 cp = strchr(disp, ':'); 4848 if (cp) 4849 cp = strchr(cp, '.'); 4850 if (cp) 4851 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 4852 else 4853 screen_number = 0; 4854 4855 if (sc->x11_saved_proto == NULL) { 4856 /* Save protocol name. */ 4857 sc->x11_saved_proto = xstrdup(proto); 4858 4859 /* Extract real authentication data. */ 4860 sc->x11_saved_data = xmalloc(data_len); 4861 for (i = 0; i < data_len; i++) { 4862 if (sscanf(data + 2 * i, "%2x", &value) != 1) 4863 fatal("x11_request_forwarding: bad " 4864 "authentication data: %.100s", data); 4865 sc->x11_saved_data[i] = value; 4866 } 4867 sc->x11_saved_data_len = data_len; 4868 4869 /* Generate fake data of the same length. */ 4870 sc->x11_fake_data = xmalloc(data_len); 4871 arc4random_buf(sc->x11_fake_data, data_len); 4872 sc->x11_fake_data_len = data_len; 4873 } 4874 4875 /* Convert the fake data into hex. */ 4876 new_data = tohex(sc->x11_fake_data, data_len); 4877 4878 /* Send the request packet. */ 4879 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 4880 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 4881 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 4882 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 4883 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 4884 (r = sshpkt_send(ssh)) != 0 || 4885 (r = ssh_packet_write_wait(ssh)) < 0) 4886 fatal("%s: send x11-req: %s", __func__, ssh_err(r)); 4887 4888 free(new_data); 4889 } 4890