1 /* $OpenBSD: channels.c,v 1.402 2020/09/20 05:47:25 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 #include <sys/ioctl.h> 45 #include <sys/un.h> 46 #include <sys/socket.h> 47 #include <sys/time.h> 48 #include <sys/queue.h> 49 50 #include <netinet/in.h> 51 #include <arpa/inet.h> 52 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <limits.h> 56 #include <netdb.h> 57 #include <stdarg.h> 58 #include <stdint.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <termios.h> 63 #include <unistd.h> 64 65 #include "xmalloc.h" 66 #include "ssh.h" 67 #include "ssh2.h" 68 #include "ssherr.h" 69 #include "sshbuf.h" 70 #include "packet.h" 71 #include "log.h" 72 #include "misc.h" 73 #include "channels.h" 74 #include "compat.h" 75 #include "canohost.h" 76 #include "sshkey.h" 77 #include "authfd.h" 78 #include "pathnames.h" 79 #include "match.h" 80 81 /* -- agent forwarding */ 82 #define NUM_SOCKS 10 83 84 /* -- tcp forwarding */ 85 /* special-case port number meaning allow any port */ 86 #define FWD_PERMIT_ANY_PORT 0 87 88 /* special-case wildcard meaning allow any host */ 89 #define FWD_PERMIT_ANY_HOST "*" 90 91 /* -- X11 forwarding */ 92 /* Maximum number of fake X11 displays to try. */ 93 #define MAX_DISPLAYS 1000 94 95 /* Per-channel callback for pre/post select() actions */ 96 typedef void chan_fn(struct ssh *, Channel *c, 97 fd_set *readset, fd_set *writeset); 98 99 /* 100 * Data structure for storing which hosts are permitted for forward requests. 101 * The local sides of any remote forwards are stored in this array to prevent 102 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 103 * network (which might be behind a firewall). 104 */ 105 /* XXX: streamlocal wants a path instead of host:port */ 106 /* Overload host_to_connect; we could just make this match Forward */ 107 /* XXX - can we use listen_host instead of listen_path? */ 108 struct permission { 109 char *host_to_connect; /* Connect to 'host'. */ 110 int port_to_connect; /* Connect to 'port'. */ 111 char *listen_host; /* Remote side should listen address. */ 112 char *listen_path; /* Remote side should listen path. */ 113 int listen_port; /* Remote side should listen port. */ 114 Channel *downstream; /* Downstream mux*/ 115 }; 116 117 /* 118 * Stores the forwarding permission state for a single direction (local or 119 * remote). 120 */ 121 struct permission_set { 122 /* 123 * List of all local permitted host/port pairs to allow for the 124 * user. 125 */ 126 u_int num_permitted_user; 127 struct permission *permitted_user; 128 129 /* 130 * List of all permitted host/port pairs to allow for the admin. 131 */ 132 u_int num_permitted_admin; 133 struct permission *permitted_admin; 134 135 /* 136 * If this is true, all opens/listens are permitted. This is the 137 * case on the server on which we have to trust the client anyway, 138 * and the user could do anything after logging in. 139 */ 140 int all_permitted; 141 }; 142 143 /* Master structure for channels state */ 144 struct ssh_channels { 145 /* 146 * Pointer to an array containing all allocated channels. The array 147 * is dynamically extended as needed. 148 */ 149 Channel **channels; 150 151 /* 152 * Size of the channel array. All slots of the array must always be 153 * initialized (at least the type field); unused slots set to NULL 154 */ 155 u_int channels_alloc; 156 157 /* 158 * Maximum file descriptor value used in any of the channels. This is 159 * updated in channel_new. 160 */ 161 int channel_max_fd; 162 163 /* 164 * 'channel_pre*' are called just before select() to add any bits 165 * relevant to channels in the select bitmasks. 166 * 167 * 'channel_post*': perform any appropriate operations for 168 * channels which have events pending. 169 */ 170 chan_fn **channel_pre; 171 chan_fn **channel_post; 172 173 /* -- tcp forwarding */ 174 struct permission_set local_perms; 175 struct permission_set remote_perms; 176 177 /* -- X11 forwarding */ 178 179 /* Saved X11 local (client) display. */ 180 char *x11_saved_display; 181 182 /* Saved X11 authentication protocol name. */ 183 char *x11_saved_proto; 184 185 /* Saved X11 authentication data. This is the real data. */ 186 char *x11_saved_data; 187 u_int x11_saved_data_len; 188 189 /* Deadline after which all X11 connections are refused */ 190 u_int x11_refuse_time; 191 192 /* 193 * Fake X11 authentication data. This is what the server will be 194 * sending us; we should replace any occurrences of this by the 195 * real data. 196 */ 197 u_char *x11_fake_data; 198 u_int x11_fake_data_len; 199 200 /* AF_UNSPEC or AF_INET or AF_INET6 */ 201 int IPv4or6; 202 }; 203 204 /* helper */ 205 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 206 static const char *channel_rfwd_bind_host(const char *listen_host); 207 208 /* non-blocking connect helpers */ 209 static int connect_next(struct channel_connect *); 210 static void channel_connect_ctx_free(struct channel_connect *); 211 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 212 static int rdynamic_connect_finish(struct ssh *, Channel *); 213 214 /* Setup helper */ 215 static void channel_handler_init(struct ssh_channels *sc); 216 217 /* -- channel core */ 218 219 void 220 channel_init_channels(struct ssh *ssh) 221 { 222 struct ssh_channels *sc; 223 224 if ((sc = calloc(1, sizeof(*sc))) == NULL) 225 fatal("%s: allocation failed", __func__); 226 sc->channels_alloc = 10; 227 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 228 sc->IPv4or6 = AF_UNSPEC; 229 channel_handler_init(sc); 230 231 ssh->chanctxt = sc; 232 } 233 234 Channel * 235 channel_by_id(struct ssh *ssh, int id) 236 { 237 Channel *c; 238 239 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 240 logit("%s: %d: bad id", __func__, id); 241 return NULL; 242 } 243 c = ssh->chanctxt->channels[id]; 244 if (c == NULL) { 245 logit("%s: %d: bad id: channel free", __func__, id); 246 return NULL; 247 } 248 return c; 249 } 250 251 Channel * 252 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 253 { 254 Channel *c; 255 u_int i; 256 257 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 258 c = ssh->chanctxt->channels[i]; 259 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 260 return c; 261 } 262 return NULL; 263 } 264 265 /* 266 * Returns the channel if it is allowed to receive protocol messages. 267 * Private channels, like listening sockets, may not receive messages. 268 */ 269 Channel * 270 channel_lookup(struct ssh *ssh, int id) 271 { 272 Channel *c; 273 274 if ((c = channel_by_id(ssh, id)) == NULL) 275 return NULL; 276 277 switch (c->type) { 278 case SSH_CHANNEL_X11_OPEN: 279 case SSH_CHANNEL_LARVAL: 280 case SSH_CHANNEL_CONNECTING: 281 case SSH_CHANNEL_DYNAMIC: 282 case SSH_CHANNEL_RDYNAMIC_OPEN: 283 case SSH_CHANNEL_RDYNAMIC_FINISH: 284 case SSH_CHANNEL_OPENING: 285 case SSH_CHANNEL_OPEN: 286 case SSH_CHANNEL_ABANDONED: 287 case SSH_CHANNEL_MUX_PROXY: 288 return c; 289 } 290 logit("Non-public channel %d, type %d.", id, c->type); 291 return NULL; 292 } 293 294 /* 295 * Register filedescriptors for a channel, used when allocating a channel or 296 * when the channel consumer/producer is ready, e.g. shell exec'd 297 */ 298 static void 299 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 300 int extusage, int nonblock, int is_tty) 301 { 302 struct ssh_channels *sc = ssh->chanctxt; 303 304 /* Update the maximum file descriptor value. */ 305 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, rfd); 306 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, wfd); 307 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, efd); 308 309 if (rfd != -1) 310 fcntl(rfd, F_SETFD, FD_CLOEXEC); 311 if (wfd != -1 && wfd != rfd) 312 fcntl(wfd, F_SETFD, FD_CLOEXEC); 313 if (efd != -1 && efd != rfd && efd != wfd) 314 fcntl(efd, F_SETFD, FD_CLOEXEC); 315 316 c->rfd = rfd; 317 c->wfd = wfd; 318 c->sock = (rfd == wfd) ? rfd : -1; 319 c->efd = efd; 320 c->extended_usage = extusage; 321 322 if ((c->isatty = is_tty) != 0) 323 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 324 325 /* enable nonblocking mode */ 326 if (nonblock) { 327 if (rfd != -1) 328 set_nonblock(rfd); 329 if (wfd != -1) 330 set_nonblock(wfd); 331 if (efd != -1) 332 set_nonblock(efd); 333 } 334 } 335 336 /* 337 * Allocate a new channel object and set its type and socket. This will cause 338 * remote_name to be freed. 339 */ 340 Channel * 341 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 342 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) 343 { 344 struct ssh_channels *sc = ssh->chanctxt; 345 u_int i, found; 346 Channel *c; 347 int r; 348 349 /* Try to find a free slot where to put the new channel. */ 350 for (i = 0; i < sc->channels_alloc; i++) { 351 if (sc->channels[i] == NULL) { 352 /* Found a free slot. */ 353 found = i; 354 break; 355 } 356 } 357 if (i >= sc->channels_alloc) { 358 /* 359 * There are no free slots. Take last+1 slot and expand 360 * the array. 361 */ 362 found = sc->channels_alloc; 363 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 364 fatal("%s: internal error: channels_alloc %d too big", 365 __func__, sc->channels_alloc); 366 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 367 sc->channels_alloc + 10, sizeof(*sc->channels)); 368 sc->channels_alloc += 10; 369 debug2("channel: expanding %d", sc->channels_alloc); 370 } 371 /* Initialize and return new channel. */ 372 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 373 if ((c->input = sshbuf_new()) == NULL || 374 (c->output = sshbuf_new()) == NULL || 375 (c->extended = sshbuf_new()) == NULL) 376 fatal("%s: sshbuf_new failed", __func__); 377 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 378 fatal("%s: sshbuf_set_max_size: %s", __func__, ssh_err(r)); 379 c->ostate = CHAN_OUTPUT_OPEN; 380 c->istate = CHAN_INPUT_OPEN; 381 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 382 c->self = found; 383 c->type = type; 384 c->ctype = ctype; 385 c->local_window = window; 386 c->local_window_max = window; 387 c->local_maxpacket = maxpack; 388 c->remote_name = xstrdup(remote_name); 389 c->ctl_chan = -1; 390 c->delayed = 1; /* prevent call to channel_post handler */ 391 TAILQ_INIT(&c->status_confirms); 392 debug("channel %d: new [%s]", found, remote_name); 393 return c; 394 } 395 396 static void 397 channel_find_maxfd(struct ssh_channels *sc) 398 { 399 u_int i; 400 int max = 0; 401 Channel *c; 402 403 for (i = 0; i < sc->channels_alloc; i++) { 404 c = sc->channels[i]; 405 if (c != NULL) { 406 max = MAXIMUM(max, c->rfd); 407 max = MAXIMUM(max, c->wfd); 408 max = MAXIMUM(max, c->efd); 409 } 410 } 411 sc->channel_max_fd = max; 412 } 413 414 int 415 channel_close_fd(struct ssh *ssh, int *fdp) 416 { 417 struct ssh_channels *sc = ssh->chanctxt; 418 int ret = 0, fd = *fdp; 419 420 if (fd != -1) { 421 ret = close(fd); 422 *fdp = -1; 423 if (fd == sc->channel_max_fd) 424 channel_find_maxfd(sc); 425 } 426 return ret; 427 } 428 429 /* Close all channel fd/socket. */ 430 static void 431 channel_close_fds(struct ssh *ssh, Channel *c) 432 { 433 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 434 435 channel_close_fd(ssh, &c->sock); 436 if (rfd != sock) 437 channel_close_fd(ssh, &c->rfd); 438 if (wfd != sock && wfd != rfd) 439 channel_close_fd(ssh, &c->wfd); 440 if (efd != sock && efd != rfd && efd != wfd) 441 channel_close_fd(ssh, &c->efd); 442 } 443 444 static void 445 fwd_perm_clear(struct permission *perm) 446 { 447 free(perm->host_to_connect); 448 free(perm->listen_host); 449 free(perm->listen_path); 450 memset(perm, 0, sizeof(*perm)); 451 } 452 453 /* Returns an printable name for the specified forwarding permission list */ 454 static const char * 455 fwd_ident(int who, int where) 456 { 457 if (who == FORWARD_ADM) { 458 if (where == FORWARD_LOCAL) 459 return "admin local"; 460 else if (where == FORWARD_REMOTE) 461 return "admin remote"; 462 } else if (who == FORWARD_USER) { 463 if (where == FORWARD_LOCAL) 464 return "user local"; 465 else if (where == FORWARD_REMOTE) 466 return "user remote"; 467 } 468 fatal("Unknown forward permission list %d/%d", who, where); 469 } 470 471 /* Returns the forwarding permission list for the specified direction */ 472 static struct permission_set * 473 permission_set_get(struct ssh *ssh, int where) 474 { 475 struct ssh_channels *sc = ssh->chanctxt; 476 477 switch (where) { 478 case FORWARD_LOCAL: 479 return &sc->local_perms; 480 break; 481 case FORWARD_REMOTE: 482 return &sc->remote_perms; 483 break; 484 default: 485 fatal("%s: invalid forwarding direction %d", __func__, where); 486 } 487 } 488 489 /* Returns pointers to the specified forwarding list and its element count */ 490 static void 491 permission_set_get_array(struct ssh *ssh, int who, int where, 492 struct permission ***permpp, u_int **npermpp) 493 { 494 struct permission_set *pset = permission_set_get(ssh, where); 495 496 switch (who) { 497 case FORWARD_USER: 498 *permpp = &pset->permitted_user; 499 *npermpp = &pset->num_permitted_user; 500 break; 501 case FORWARD_ADM: 502 *permpp = &pset->permitted_admin; 503 *npermpp = &pset->num_permitted_admin; 504 break; 505 default: 506 fatal("%s: invalid forwarding client %d", __func__, who); 507 } 508 } 509 510 /* Adds an entry to the spcified forwarding list */ 511 static int 512 permission_set_add(struct ssh *ssh, int who, int where, 513 const char *host_to_connect, int port_to_connect, 514 const char *listen_host, const char *listen_path, int listen_port, 515 Channel *downstream) 516 { 517 struct permission **permp; 518 u_int n, *npermp; 519 520 permission_set_get_array(ssh, who, where, &permp, &npermp); 521 522 if (*npermp >= INT_MAX) 523 fatal("%s: %s overflow", __func__, fwd_ident(who, where)); 524 525 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 526 n = (*npermp)++; 527 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 528 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 529 (*permp)[n].port_to_connect = port_to_connect; 530 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 531 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 532 (*permp)[n].listen_port = listen_port; 533 (*permp)[n].downstream = downstream; 534 #undef MAYBE_DUP 535 return (int)n; 536 } 537 538 static void 539 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 540 { 541 struct ssh_channels *sc = ssh->chanctxt; 542 struct permission_set *pset = &sc->local_perms; 543 struct permission *perm; 544 int r; 545 u_int i; 546 547 for (i = 0; i < pset->num_permitted_user; i++) { 548 perm = &pset->permitted_user[i]; 549 if (perm->downstream != c) 550 continue; 551 552 /* cancel on the server, since mux client is gone */ 553 debug("channel %d: cleanup remote forward for %s:%u", 554 c->self, perm->listen_host, perm->listen_port); 555 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 556 (r = sshpkt_put_cstring(ssh, 557 "cancel-tcpip-forward")) != 0 || 558 (r = sshpkt_put_u8(ssh, 0)) != 0 || 559 (r = sshpkt_put_cstring(ssh, 560 channel_rfwd_bind_host(perm->listen_host))) != 0 || 561 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 562 (r = sshpkt_send(ssh)) != 0) { 563 fatal("%s: channel %i: %s", __func__, 564 c->self, ssh_err(r)); 565 } 566 fwd_perm_clear(perm); /* unregister */ 567 } 568 } 569 570 /* Free the channel and close its fd/socket. */ 571 void 572 channel_free(struct ssh *ssh, Channel *c) 573 { 574 struct ssh_channels *sc = ssh->chanctxt; 575 char *s; 576 u_int i, n; 577 Channel *other; 578 struct channel_confirm *cc; 579 580 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 581 if ((other = sc->channels[i]) == NULL) 582 continue; 583 n++; 584 /* detach from mux client and prepare for closing */ 585 if (c->type == SSH_CHANNEL_MUX_CLIENT && 586 other->type == SSH_CHANNEL_MUX_PROXY && 587 other->mux_ctx == c) { 588 other->mux_ctx = NULL; 589 other->type = SSH_CHANNEL_OPEN; 590 other->istate = CHAN_INPUT_CLOSED; 591 other->ostate = CHAN_OUTPUT_CLOSED; 592 } 593 } 594 debug("channel %d: free: %s, nchannels %u", c->self, 595 c->remote_name ? c->remote_name : "???", n); 596 597 if (c->type == SSH_CHANNEL_MUX_CLIENT) 598 mux_remove_remote_forwardings(ssh, c); 599 else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 600 free(c->mux_ctx); 601 c->mux_ctx = NULL; 602 } 603 604 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 605 s = channel_open_message(ssh); 606 debug3("channel %d: status: %s", c->self, s); 607 free(s); 608 } 609 610 channel_close_fds(ssh, c); 611 sshbuf_free(c->input); 612 sshbuf_free(c->output); 613 sshbuf_free(c->extended); 614 c->input = c->output = c->extended = NULL; 615 free(c->remote_name); 616 c->remote_name = NULL; 617 free(c->path); 618 c->path = NULL; 619 free(c->listening_addr); 620 c->listening_addr = NULL; 621 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 622 if (cc->abandon_cb != NULL) 623 cc->abandon_cb(ssh, c, cc->ctx); 624 TAILQ_REMOVE(&c->status_confirms, cc, entry); 625 freezero(cc, sizeof(*cc)); 626 } 627 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 628 c->filter_cleanup(ssh, c->self, c->filter_ctx); 629 sc->channels[c->self] = NULL; 630 freezero(c, sizeof(*c)); 631 } 632 633 void 634 channel_free_all(struct ssh *ssh) 635 { 636 u_int i; 637 struct ssh_channels *sc = ssh->chanctxt; 638 639 for (i = 0; i < sc->channels_alloc; i++) 640 if (sc->channels[i] != NULL) 641 channel_free(ssh, sc->channels[i]); 642 643 free(sc->channels); 644 sc->channels = NULL; 645 sc->channels_alloc = 0; 646 sc->channel_max_fd = 0; 647 648 free(sc->x11_saved_display); 649 sc->x11_saved_display = NULL; 650 651 free(sc->x11_saved_proto); 652 sc->x11_saved_proto = NULL; 653 654 free(sc->x11_saved_data); 655 sc->x11_saved_data = NULL; 656 sc->x11_saved_data_len = 0; 657 658 free(sc->x11_fake_data); 659 sc->x11_fake_data = NULL; 660 sc->x11_fake_data_len = 0; 661 } 662 663 /* 664 * Closes the sockets/fds of all channels. This is used to close extra file 665 * descriptors after a fork. 666 */ 667 void 668 channel_close_all(struct ssh *ssh) 669 { 670 u_int i; 671 672 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 673 if (ssh->chanctxt->channels[i] != NULL) 674 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 675 } 676 677 /* 678 * Stop listening to channels. 679 */ 680 void 681 channel_stop_listening(struct ssh *ssh) 682 { 683 u_int i; 684 Channel *c; 685 686 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 687 c = ssh->chanctxt->channels[i]; 688 if (c != NULL) { 689 switch (c->type) { 690 case SSH_CHANNEL_AUTH_SOCKET: 691 case SSH_CHANNEL_PORT_LISTENER: 692 case SSH_CHANNEL_RPORT_LISTENER: 693 case SSH_CHANNEL_X11_LISTENER: 694 case SSH_CHANNEL_UNIX_LISTENER: 695 case SSH_CHANNEL_RUNIX_LISTENER: 696 channel_close_fd(ssh, &c->sock); 697 channel_free(ssh, c); 698 break; 699 } 700 } 701 } 702 } 703 704 /* 705 * Returns true if no channel has too much buffered data, and false if one or 706 * more channel is overfull. 707 */ 708 int 709 channel_not_very_much_buffered_data(struct ssh *ssh) 710 { 711 u_int i; 712 u_int maxsize = ssh_packet_get_maxsize(ssh); 713 Channel *c; 714 715 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 716 c = ssh->chanctxt->channels[i]; 717 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 718 continue; 719 if (sshbuf_len(c->output) > maxsize) { 720 debug2("channel %d: big output buffer %zu > %u", 721 c->self, sshbuf_len(c->output), maxsize); 722 return 0; 723 } 724 } 725 return 1; 726 } 727 728 /* Returns true if any channel is still open. */ 729 int 730 channel_still_open(struct ssh *ssh) 731 { 732 u_int i; 733 Channel *c; 734 735 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 736 c = ssh->chanctxt->channels[i]; 737 if (c == NULL) 738 continue; 739 switch (c->type) { 740 case SSH_CHANNEL_X11_LISTENER: 741 case SSH_CHANNEL_PORT_LISTENER: 742 case SSH_CHANNEL_RPORT_LISTENER: 743 case SSH_CHANNEL_MUX_LISTENER: 744 case SSH_CHANNEL_CLOSED: 745 case SSH_CHANNEL_AUTH_SOCKET: 746 case SSH_CHANNEL_DYNAMIC: 747 case SSH_CHANNEL_RDYNAMIC_OPEN: 748 case SSH_CHANNEL_CONNECTING: 749 case SSH_CHANNEL_ZOMBIE: 750 case SSH_CHANNEL_ABANDONED: 751 case SSH_CHANNEL_UNIX_LISTENER: 752 case SSH_CHANNEL_RUNIX_LISTENER: 753 continue; 754 case SSH_CHANNEL_LARVAL: 755 continue; 756 case SSH_CHANNEL_OPENING: 757 case SSH_CHANNEL_OPEN: 758 case SSH_CHANNEL_RDYNAMIC_FINISH: 759 case SSH_CHANNEL_X11_OPEN: 760 case SSH_CHANNEL_MUX_CLIENT: 761 case SSH_CHANNEL_MUX_PROXY: 762 return 1; 763 default: 764 fatal("%s: bad channel type %d", __func__, c->type); 765 /* NOTREACHED */ 766 } 767 } 768 return 0; 769 } 770 771 /* Returns the id of an open channel suitable for keepaliving */ 772 int 773 channel_find_open(struct ssh *ssh) 774 { 775 u_int i; 776 Channel *c; 777 778 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 779 c = ssh->chanctxt->channels[i]; 780 if (c == NULL || !c->have_remote_id) 781 continue; 782 switch (c->type) { 783 case SSH_CHANNEL_CLOSED: 784 case SSH_CHANNEL_DYNAMIC: 785 case SSH_CHANNEL_RDYNAMIC_OPEN: 786 case SSH_CHANNEL_RDYNAMIC_FINISH: 787 case SSH_CHANNEL_X11_LISTENER: 788 case SSH_CHANNEL_PORT_LISTENER: 789 case SSH_CHANNEL_RPORT_LISTENER: 790 case SSH_CHANNEL_MUX_LISTENER: 791 case SSH_CHANNEL_MUX_CLIENT: 792 case SSH_CHANNEL_MUX_PROXY: 793 case SSH_CHANNEL_OPENING: 794 case SSH_CHANNEL_CONNECTING: 795 case SSH_CHANNEL_ZOMBIE: 796 case SSH_CHANNEL_ABANDONED: 797 case SSH_CHANNEL_UNIX_LISTENER: 798 case SSH_CHANNEL_RUNIX_LISTENER: 799 continue; 800 case SSH_CHANNEL_LARVAL: 801 case SSH_CHANNEL_AUTH_SOCKET: 802 case SSH_CHANNEL_OPEN: 803 case SSH_CHANNEL_X11_OPEN: 804 return i; 805 default: 806 fatal("%s: bad channel type %d", __func__, c->type); 807 /* NOTREACHED */ 808 } 809 } 810 return -1; 811 } 812 813 /* Returns the state of the channel's extended usage flag */ 814 const char * 815 channel_format_extended_usage(const Channel *c) 816 { 817 if (c->efd == -1) 818 return "closed"; 819 820 switch (c->extended_usage) { 821 case CHAN_EXTENDED_WRITE: 822 return "write"; 823 case CHAN_EXTENDED_READ: 824 return "read"; 825 case CHAN_EXTENDED_IGNORE: 826 return "ignore"; 827 default: 828 return "UNKNOWN"; 829 } 830 } 831 832 static char * 833 channel_format_status(const Channel *c) 834 { 835 char *ret = NULL; 836 837 xasprintf(&ret, "t%d %s%u i%u/%zu o%u/%zu e[%s]/%zu " 838 "fd %d/%d/%d sock %d cc %d", 839 c->type, 840 c->have_remote_id ? "r" : "nr", c->remote_id, 841 c->istate, sshbuf_len(c->input), 842 c->ostate, sshbuf_len(c->output), 843 channel_format_extended_usage(c), sshbuf_len(c->extended), 844 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan); 845 return ret; 846 } 847 848 /* 849 * Returns a message describing the currently open forwarded connections, 850 * suitable for sending to the client. The message contains crlf pairs for 851 * newlines. 852 */ 853 char * 854 channel_open_message(struct ssh *ssh) 855 { 856 struct sshbuf *buf; 857 Channel *c; 858 u_int i; 859 int r; 860 char *cp, *ret; 861 862 if ((buf = sshbuf_new()) == NULL) 863 fatal("%s: sshbuf_new", __func__); 864 if ((r = sshbuf_putf(buf, 865 "The following connections are open:\r\n")) != 0) 866 fatal("%s: sshbuf_putf: %s", __func__, ssh_err(r)); 867 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 868 c = ssh->chanctxt->channels[i]; 869 if (c == NULL) 870 continue; 871 switch (c->type) { 872 case SSH_CHANNEL_X11_LISTENER: 873 case SSH_CHANNEL_PORT_LISTENER: 874 case SSH_CHANNEL_RPORT_LISTENER: 875 case SSH_CHANNEL_CLOSED: 876 case SSH_CHANNEL_AUTH_SOCKET: 877 case SSH_CHANNEL_ZOMBIE: 878 case SSH_CHANNEL_ABANDONED: 879 case SSH_CHANNEL_MUX_LISTENER: 880 case SSH_CHANNEL_UNIX_LISTENER: 881 case SSH_CHANNEL_RUNIX_LISTENER: 882 continue; 883 case SSH_CHANNEL_LARVAL: 884 case SSH_CHANNEL_OPENING: 885 case SSH_CHANNEL_CONNECTING: 886 case SSH_CHANNEL_DYNAMIC: 887 case SSH_CHANNEL_RDYNAMIC_OPEN: 888 case SSH_CHANNEL_RDYNAMIC_FINISH: 889 case SSH_CHANNEL_OPEN: 890 case SSH_CHANNEL_X11_OPEN: 891 case SSH_CHANNEL_MUX_PROXY: 892 case SSH_CHANNEL_MUX_CLIENT: 893 cp = channel_format_status(c); 894 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 895 c->self, c->remote_name, cp)) != 0) { 896 free(cp); 897 fatal("%s: sshbuf_putf: %s", 898 __func__, ssh_err(r)); 899 } 900 free(cp); 901 continue; 902 default: 903 fatal("%s: bad channel type %d", __func__, c->type); 904 /* NOTREACHED */ 905 } 906 } 907 if ((ret = sshbuf_dup_string(buf)) == NULL) 908 fatal("%s: sshbuf_dup_string", __func__); 909 sshbuf_free(buf); 910 return ret; 911 } 912 913 static void 914 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 915 { 916 int r; 917 918 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 919 (r = sshpkt_put_cstring(ssh, type)) != 0 || 920 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 921 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 922 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 923 fatal("%s: channel %i: open: %s", where, c->self, ssh_err(r)); 924 } 925 } 926 927 void 928 channel_send_open(struct ssh *ssh, int id) 929 { 930 Channel *c = channel_lookup(ssh, id); 931 int r; 932 933 if (c == NULL) { 934 logit("channel_send_open: %d: bad id", id); 935 return; 936 } 937 debug2("channel %d: send open", id); 938 open_preamble(ssh, __func__, c, c->ctype); 939 if ((r = sshpkt_send(ssh)) != 0) 940 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 941 } 942 943 void 944 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 945 { 946 Channel *c = channel_lookup(ssh, id); 947 int r; 948 949 if (c == NULL) { 950 logit("%s: %d: unknown channel id", __func__, id); 951 return; 952 } 953 if (!c->have_remote_id) 954 fatal(":%s: channel %d: no remote id", __func__, c->self); 955 956 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 957 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 958 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 959 (r = sshpkt_put_cstring(ssh, service)) != 0 || 960 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 961 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 962 } 963 } 964 965 void 966 channel_register_status_confirm(struct ssh *ssh, int id, 967 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 968 { 969 struct channel_confirm *cc; 970 Channel *c; 971 972 if ((c = channel_lookup(ssh, id)) == NULL) 973 fatal("%s: %d: bad id", __func__, id); 974 975 cc = xcalloc(1, sizeof(*cc)); 976 cc->cb = cb; 977 cc->abandon_cb = abandon_cb; 978 cc->ctx = ctx; 979 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 980 } 981 982 void 983 channel_register_open_confirm(struct ssh *ssh, int id, 984 channel_open_fn *fn, void *ctx) 985 { 986 Channel *c = channel_lookup(ssh, id); 987 988 if (c == NULL) { 989 logit("%s: %d: bad id", __func__, id); 990 return; 991 } 992 c->open_confirm = fn; 993 c->open_confirm_ctx = ctx; 994 } 995 996 void 997 channel_register_cleanup(struct ssh *ssh, int id, 998 channel_callback_fn *fn, int do_close) 999 { 1000 Channel *c = channel_by_id(ssh, id); 1001 1002 if (c == NULL) { 1003 logit("%s: %d: bad id", __func__, id); 1004 return; 1005 } 1006 c->detach_user = fn; 1007 c->detach_close = do_close; 1008 } 1009 1010 void 1011 channel_cancel_cleanup(struct ssh *ssh, int id) 1012 { 1013 Channel *c = channel_by_id(ssh, id); 1014 1015 if (c == NULL) { 1016 logit("%s: %d: bad id", __func__, id); 1017 return; 1018 } 1019 c->detach_user = NULL; 1020 c->detach_close = 0; 1021 } 1022 1023 void 1024 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1025 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1026 { 1027 Channel *c = channel_lookup(ssh, id); 1028 1029 if (c == NULL) { 1030 logit("%s: %d: bad id", __func__, id); 1031 return; 1032 } 1033 c->input_filter = ifn; 1034 c->output_filter = ofn; 1035 c->filter_ctx = ctx; 1036 c->filter_cleanup = cfn; 1037 } 1038 1039 void 1040 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1041 int extusage, int nonblock, int is_tty, u_int window_max) 1042 { 1043 Channel *c = channel_lookup(ssh, id); 1044 int r; 1045 1046 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1047 fatal("channel_activate for non-larval channel %d.", id); 1048 if (!c->have_remote_id) 1049 fatal(":%s: channel %d: no remote id", __func__, c->self); 1050 1051 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1052 c->type = SSH_CHANNEL_OPEN; 1053 c->local_window = c->local_window_max = window_max; 1054 1055 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1056 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1057 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1058 (r = sshpkt_send(ssh)) != 0) 1059 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 1060 } 1061 1062 static void 1063 channel_pre_listener(struct ssh *ssh, Channel *c, 1064 fd_set *readset, fd_set *writeset) 1065 { 1066 FD_SET(c->sock, readset); 1067 } 1068 1069 static void 1070 channel_pre_connecting(struct ssh *ssh, Channel *c, 1071 fd_set *readset, fd_set *writeset) 1072 { 1073 debug3("channel %d: waiting for connection", c->self); 1074 FD_SET(c->sock, writeset); 1075 } 1076 1077 static void 1078 channel_pre_open(struct ssh *ssh, Channel *c, 1079 fd_set *readset, fd_set *writeset) 1080 { 1081 if (c->istate == CHAN_INPUT_OPEN && 1082 c->remote_window > 0 && 1083 sshbuf_len(c->input) < c->remote_window && 1084 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1085 FD_SET(c->rfd, readset); 1086 if (c->ostate == CHAN_OUTPUT_OPEN || 1087 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1088 if (sshbuf_len(c->output) > 0) { 1089 FD_SET(c->wfd, writeset); 1090 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1091 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1092 debug2("channel %d: " 1093 "obuf_empty delayed efd %d/(%zu)", c->self, 1094 c->efd, sshbuf_len(c->extended)); 1095 else 1096 chan_obuf_empty(ssh, c); 1097 } 1098 } 1099 /** XXX check close conditions, too */ 1100 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1101 c->ostate == CHAN_OUTPUT_CLOSED)) { 1102 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1103 sshbuf_len(c->extended) > 0) 1104 FD_SET(c->efd, writeset); 1105 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1106 (c->extended_usage == CHAN_EXTENDED_READ || 1107 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1108 sshbuf_len(c->extended) < c->remote_window) 1109 FD_SET(c->efd, readset); 1110 } 1111 /* XXX: What about efd? races? */ 1112 } 1113 1114 /* 1115 * This is a special state for X11 authentication spoofing. An opened X11 1116 * connection (when authentication spoofing is being done) remains in this 1117 * state until the first packet has been completely read. The authentication 1118 * data in that packet is then substituted by the real data if it matches the 1119 * fake data, and the channel is put into normal mode. 1120 * XXX All this happens at the client side. 1121 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1122 */ 1123 static int 1124 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1125 { 1126 struct ssh_channels *sc = ssh->chanctxt; 1127 u_char *ucp; 1128 u_int proto_len, data_len; 1129 1130 /* Is this being called after the refusal deadline? */ 1131 if (sc->x11_refuse_time != 0 && 1132 (u_int)monotime() >= sc->x11_refuse_time) { 1133 verbose("Rejected X11 connection after ForwardX11Timeout " 1134 "expired"); 1135 return -1; 1136 } 1137 1138 /* Check if the fixed size part of the packet is in buffer. */ 1139 if (sshbuf_len(b) < 12) 1140 return 0; 1141 1142 /* Parse the lengths of variable-length fields. */ 1143 ucp = sshbuf_mutable_ptr(b); 1144 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1145 proto_len = 256 * ucp[6] + ucp[7]; 1146 data_len = 256 * ucp[8] + ucp[9]; 1147 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1148 proto_len = ucp[6] + 256 * ucp[7]; 1149 data_len = ucp[8] + 256 * ucp[9]; 1150 } else { 1151 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1152 ucp[0]); 1153 return -1; 1154 } 1155 1156 /* Check if the whole packet is in buffer. */ 1157 if (sshbuf_len(b) < 1158 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1159 return 0; 1160 1161 /* Check if authentication protocol matches. */ 1162 if (proto_len != strlen(sc->x11_saved_proto) || 1163 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1164 debug2("X11 connection uses different authentication protocol."); 1165 return -1; 1166 } 1167 /* Check if authentication data matches our fake data. */ 1168 if (data_len != sc->x11_fake_data_len || 1169 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1170 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1171 debug2("X11 auth data does not match fake data."); 1172 return -1; 1173 } 1174 /* Check fake data length */ 1175 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1176 error("X11 fake_data_len %d != saved_data_len %d", 1177 sc->x11_fake_data_len, sc->x11_saved_data_len); 1178 return -1; 1179 } 1180 /* 1181 * Received authentication protocol and data match 1182 * our fake data. Substitute the fake data with real 1183 * data. 1184 */ 1185 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1186 sc->x11_saved_data, sc->x11_saved_data_len); 1187 return 1; 1188 } 1189 1190 static void 1191 channel_pre_x11_open(struct ssh *ssh, Channel *c, 1192 fd_set *readset, fd_set *writeset) 1193 { 1194 int ret = x11_open_helper(ssh, c->output); 1195 1196 /* c->force_drain = 1; */ 1197 1198 if (ret == 1) { 1199 c->type = SSH_CHANNEL_OPEN; 1200 channel_pre_open(ssh, c, readset, writeset); 1201 } else if (ret == -1) { 1202 logit("X11 connection rejected because of wrong authentication."); 1203 debug2("X11 rejected %d i%d/o%d", 1204 c->self, c->istate, c->ostate); 1205 chan_read_failed(ssh, c); 1206 sshbuf_reset(c->input); 1207 chan_ibuf_empty(ssh, c); 1208 sshbuf_reset(c->output); 1209 chan_write_failed(ssh, c); 1210 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1211 } 1212 } 1213 1214 static void 1215 channel_pre_mux_client(struct ssh *ssh, 1216 Channel *c, fd_set *readset, fd_set *writeset) 1217 { 1218 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1219 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1220 FD_SET(c->rfd, readset); 1221 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1222 /* clear buffer immediately (discard any partial packet) */ 1223 sshbuf_reset(c->input); 1224 chan_ibuf_empty(ssh, c); 1225 /* Start output drain. XXX just kill chan? */ 1226 chan_rcvd_oclose(ssh, c); 1227 } 1228 if (c->ostate == CHAN_OUTPUT_OPEN || 1229 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1230 if (sshbuf_len(c->output) > 0) 1231 FD_SET(c->wfd, writeset); 1232 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1233 chan_obuf_empty(ssh, c); 1234 } 1235 } 1236 1237 /* try to decode a socks4 header */ 1238 static int 1239 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1240 { 1241 const u_char *p; 1242 char *host; 1243 u_int len, have, i, found, need; 1244 char username[256]; 1245 struct { 1246 u_int8_t version; 1247 u_int8_t command; 1248 u_int16_t dest_port; 1249 struct in_addr dest_addr; 1250 } s4_req, s4_rsp; 1251 int r; 1252 1253 debug2("channel %d: decode socks4", c->self); 1254 1255 have = sshbuf_len(input); 1256 len = sizeof(s4_req); 1257 if (have < len) 1258 return 0; 1259 p = sshbuf_ptr(input); 1260 1261 need = 1; 1262 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1263 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1264 debug2("channel %d: socks4a request", c->self); 1265 /* ... and needs an extra string (the hostname) */ 1266 need = 2; 1267 } 1268 /* Check for terminating NUL on the string(s) */ 1269 for (found = 0, i = len; i < have; i++) { 1270 if (p[i] == '\0') { 1271 found++; 1272 if (found == need) 1273 break; 1274 } 1275 if (i > 1024) { 1276 /* the peer is probably sending garbage */ 1277 debug("channel %d: decode socks4: too long", 1278 c->self); 1279 return -1; 1280 } 1281 } 1282 if (found < need) 1283 return 0; 1284 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1285 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1286 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1287 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1288 debug("channels %d: decode socks4: %s", c->self, ssh_err(r)); 1289 return -1; 1290 } 1291 have = sshbuf_len(input); 1292 p = sshbuf_ptr(input); 1293 if (memchr(p, '\0', have) == NULL) { 1294 error("channel %d: decode socks4: user not nul terminated", 1295 c->self); 1296 return -1; 1297 } 1298 len = strlen(p); 1299 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1300 len++; /* trailing '\0' */ 1301 strlcpy(username, p, sizeof(username)); 1302 if ((r = sshbuf_consume(input, len)) != 0) { 1303 fatal("%s: channel %d: consume: %s", __func__, 1304 c->self, ssh_err(r)); 1305 } 1306 free(c->path); 1307 c->path = NULL; 1308 if (need == 1) { /* SOCKS4: one string */ 1309 host = inet_ntoa(s4_req.dest_addr); 1310 c->path = xstrdup(host); 1311 } else { /* SOCKS4A: two strings */ 1312 have = sshbuf_len(input); 1313 p = sshbuf_ptr(input); 1314 if (memchr(p, '\0', have) == NULL) { 1315 error("channel %d: decode socks4a: host not nul " 1316 "terminated", c->self); 1317 return -1; 1318 } 1319 len = strlen(p); 1320 debug2("channel %d: decode socks4a: host %s/%d", 1321 c->self, p, len); 1322 len++; /* trailing '\0' */ 1323 if (len > NI_MAXHOST) { 1324 error("channel %d: hostname \"%.100s\" too long", 1325 c->self, p); 1326 return -1; 1327 } 1328 c->path = xstrdup(p); 1329 if ((r = sshbuf_consume(input, len)) != 0) { 1330 fatal("%s: channel %d: consume: %s", __func__, 1331 c->self, ssh_err(r)); 1332 } 1333 } 1334 c->host_port = ntohs(s4_req.dest_port); 1335 1336 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1337 c->self, c->path, c->host_port, s4_req.command); 1338 1339 if (s4_req.command != 1) { 1340 debug("channel %d: cannot handle: %s cn %d", 1341 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1342 return -1; 1343 } 1344 s4_rsp.version = 0; /* vn: 0 for reply */ 1345 s4_rsp.command = 90; /* cd: req granted */ 1346 s4_rsp.dest_port = 0; /* ignored */ 1347 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1348 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) { 1349 fatal("%s: channel %d: append reply: %s", __func__, 1350 c->self, ssh_err(r)); 1351 } 1352 return 1; 1353 } 1354 1355 /* try to decode a socks5 header */ 1356 #define SSH_SOCKS5_AUTHDONE 0x1000 1357 #define SSH_SOCKS5_NOAUTH 0x00 1358 #define SSH_SOCKS5_IPV4 0x01 1359 #define SSH_SOCKS5_DOMAIN 0x03 1360 #define SSH_SOCKS5_IPV6 0x04 1361 #define SSH_SOCKS5_CONNECT 0x01 1362 #define SSH_SOCKS5_SUCCESS 0x00 1363 1364 static int 1365 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1366 { 1367 /* XXX use get/put_u8 instead of trusting struct padding */ 1368 struct { 1369 u_int8_t version; 1370 u_int8_t command; 1371 u_int8_t reserved; 1372 u_int8_t atyp; 1373 } s5_req, s5_rsp; 1374 u_int16_t dest_port; 1375 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1376 const u_char *p; 1377 u_int have, need, i, found, nmethods, addrlen, af; 1378 int r; 1379 1380 debug2("channel %d: decode socks5", c->self); 1381 p = sshbuf_ptr(input); 1382 if (p[0] != 0x05) 1383 return -1; 1384 have = sshbuf_len(input); 1385 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1386 /* format: ver | nmethods | methods */ 1387 if (have < 2) 1388 return 0; 1389 nmethods = p[1]; 1390 if (have < nmethods + 2) 1391 return 0; 1392 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1393 for (found = 0, i = 2; i < nmethods + 2; i++) { 1394 if (p[i] == SSH_SOCKS5_NOAUTH) { 1395 found = 1; 1396 break; 1397 } 1398 } 1399 if (!found) { 1400 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1401 c->self); 1402 return -1; 1403 } 1404 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) { 1405 fatal("%s: channel %d: consume: %s", __func__, 1406 c->self, ssh_err(r)); 1407 } 1408 /* version, method */ 1409 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1410 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) { 1411 fatal("%s: channel %d: append reply: %s", __func__, 1412 c->self, ssh_err(r)); 1413 } 1414 c->flags |= SSH_SOCKS5_AUTHDONE; 1415 debug2("channel %d: socks5 auth done", c->self); 1416 return 0; /* need more */ 1417 } 1418 debug2("channel %d: socks5 post auth", c->self); 1419 if (have < sizeof(s5_req)+1) 1420 return 0; /* need more */ 1421 memcpy(&s5_req, p, sizeof(s5_req)); 1422 if (s5_req.version != 0x05 || 1423 s5_req.command != SSH_SOCKS5_CONNECT || 1424 s5_req.reserved != 0x00) { 1425 debug2("channel %d: only socks5 connect supported", c->self); 1426 return -1; 1427 } 1428 switch (s5_req.atyp){ 1429 case SSH_SOCKS5_IPV4: 1430 addrlen = 4; 1431 af = AF_INET; 1432 break; 1433 case SSH_SOCKS5_DOMAIN: 1434 addrlen = p[sizeof(s5_req)]; 1435 af = -1; 1436 break; 1437 case SSH_SOCKS5_IPV6: 1438 addrlen = 16; 1439 af = AF_INET6; 1440 break; 1441 default: 1442 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1443 return -1; 1444 } 1445 need = sizeof(s5_req) + addrlen + 2; 1446 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1447 need++; 1448 if (have < need) 1449 return 0; 1450 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) { 1451 fatal("%s: channel %d: consume: %s", __func__, 1452 c->self, ssh_err(r)); 1453 } 1454 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1455 /* host string length */ 1456 if ((r = sshbuf_consume(input, 1)) != 0) { 1457 fatal("%s: channel %d: consume: %s", __func__, 1458 c->self, ssh_err(r)); 1459 } 1460 } 1461 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1462 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1463 debug("channel %d: parse addr/port: %s", c->self, ssh_err(r)); 1464 return -1; 1465 } 1466 dest_addr[addrlen] = '\0'; 1467 free(c->path); 1468 c->path = NULL; 1469 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1470 if (addrlen >= NI_MAXHOST) { 1471 error("channel %d: dynamic request: socks5 hostname " 1472 "\"%.100s\" too long", c->self, dest_addr); 1473 return -1; 1474 } 1475 c->path = xstrdup(dest_addr); 1476 } else { 1477 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1478 return -1; 1479 c->path = xstrdup(ntop); 1480 } 1481 c->host_port = ntohs(dest_port); 1482 1483 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1484 c->self, c->path, c->host_port, s5_req.command); 1485 1486 s5_rsp.version = 0x05; 1487 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1488 s5_rsp.reserved = 0; /* ignored */ 1489 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1490 dest_port = 0; /* ignored */ 1491 1492 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1493 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1494 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1495 fatal("%s: channel %d: append reply: %s", __func__, 1496 c->self, ssh_err(r)); 1497 return 1; 1498 } 1499 1500 Channel * 1501 channel_connect_stdio_fwd(struct ssh *ssh, 1502 const char *host_to_connect, u_short port_to_connect, int in, int out) 1503 { 1504 Channel *c; 1505 1506 debug("%s %s:%d", __func__, host_to_connect, port_to_connect); 1507 1508 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1509 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1510 0, "stdio-forward", /*nonblock*/0); 1511 1512 c->path = xstrdup(host_to_connect); 1513 c->host_port = port_to_connect; 1514 c->listening_port = 0; 1515 c->force_drain = 1; 1516 1517 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1518 port_open_helper(ssh, c, "direct-tcpip"); 1519 1520 return c; 1521 } 1522 1523 /* dynamic port forwarding */ 1524 static void 1525 channel_pre_dynamic(struct ssh *ssh, Channel *c, 1526 fd_set *readset, fd_set *writeset) 1527 { 1528 const u_char *p; 1529 u_int have; 1530 int ret; 1531 1532 have = sshbuf_len(c->input); 1533 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1534 /* sshbuf_dump(c->input, stderr); */ 1535 /* check if the fixed size part of the packet is in buffer. */ 1536 if (have < 3) { 1537 /* need more */ 1538 FD_SET(c->sock, readset); 1539 return; 1540 } 1541 /* try to guess the protocol */ 1542 p = sshbuf_ptr(c->input); 1543 /* XXX sshbuf_peek_u8? */ 1544 switch (p[0]) { 1545 case 0x04: 1546 ret = channel_decode_socks4(c, c->input, c->output); 1547 break; 1548 case 0x05: 1549 ret = channel_decode_socks5(c, c->input, c->output); 1550 break; 1551 default: 1552 ret = -1; 1553 break; 1554 } 1555 if (ret < 0) { 1556 chan_mark_dead(ssh, c); 1557 } else if (ret == 0) { 1558 debug2("channel %d: pre_dynamic: need more", c->self); 1559 /* need more */ 1560 FD_SET(c->sock, readset); 1561 if (sshbuf_len(c->output)) 1562 FD_SET(c->sock, writeset); 1563 } else { 1564 /* switch to the next state */ 1565 c->type = SSH_CHANNEL_OPENING; 1566 port_open_helper(ssh, c, "direct-tcpip"); 1567 } 1568 } 1569 1570 /* simulate read-error */ 1571 static void 1572 rdynamic_close(struct ssh *ssh, Channel *c) 1573 { 1574 c->type = SSH_CHANNEL_OPEN; 1575 chan_read_failed(ssh, c); 1576 sshbuf_reset(c->input); 1577 chan_ibuf_empty(ssh, c); 1578 sshbuf_reset(c->output); 1579 chan_write_failed(ssh, c); 1580 } 1581 1582 /* reverse dynamic port forwarding */ 1583 static void 1584 channel_before_prepare_select_rdynamic(struct ssh *ssh, Channel *c) 1585 { 1586 const u_char *p; 1587 u_int have, len; 1588 int r, ret; 1589 1590 have = sshbuf_len(c->output); 1591 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1592 /* sshbuf_dump(c->output, stderr); */ 1593 /* EOF received */ 1594 if (c->flags & CHAN_EOF_RCVD) { 1595 if ((r = sshbuf_consume(c->output, have)) != 0) { 1596 fatal("%s: channel %d: consume: %s", 1597 __func__, c->self, ssh_err(r)); 1598 } 1599 rdynamic_close(ssh, c); 1600 return; 1601 } 1602 /* check if the fixed size part of the packet is in buffer. */ 1603 if (have < 3) 1604 return; 1605 /* try to guess the protocol */ 1606 p = sshbuf_ptr(c->output); 1607 switch (p[0]) { 1608 case 0x04: 1609 /* switch input/output for reverse forwarding */ 1610 ret = channel_decode_socks4(c, c->output, c->input); 1611 break; 1612 case 0x05: 1613 ret = channel_decode_socks5(c, c->output, c->input); 1614 break; 1615 default: 1616 ret = -1; 1617 break; 1618 } 1619 if (ret < 0) { 1620 rdynamic_close(ssh, c); 1621 } else if (ret == 0) { 1622 debug2("channel %d: pre_rdynamic: need more", c->self); 1623 /* send socks request to peer */ 1624 len = sshbuf_len(c->input); 1625 if (len > 0 && len < c->remote_window) { 1626 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1627 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1628 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1629 (r = sshpkt_send(ssh)) != 0) { 1630 fatal("%s: channel %i: rdynamic: %s", __func__, 1631 c->self, ssh_err(r)); 1632 } 1633 if ((r = sshbuf_consume(c->input, len)) != 0) { 1634 fatal("%s: channel %d: consume: %s", 1635 __func__, c->self, ssh_err(r)); 1636 } 1637 c->remote_window -= len; 1638 } 1639 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1640 /* the connect failed */ 1641 rdynamic_close(ssh, c); 1642 } 1643 } 1644 1645 /* This is our fake X11 server socket. */ 1646 static void 1647 channel_post_x11_listener(struct ssh *ssh, Channel *c, 1648 fd_set *readset, fd_set *writeset) 1649 { 1650 Channel *nc; 1651 struct sockaddr_storage addr; 1652 int r, newsock, oerrno, remote_port; 1653 socklen_t addrlen; 1654 char buf[16384], *remote_ipaddr; 1655 1656 if (!FD_ISSET(c->sock, readset)) 1657 return; 1658 1659 debug("X11 connection requested."); 1660 addrlen = sizeof(addr); 1661 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1662 if (c->single_connection) { 1663 oerrno = errno; 1664 debug2("single_connection: closing X11 listener."); 1665 channel_close_fd(ssh, &c->sock); 1666 chan_mark_dead(ssh, c); 1667 errno = oerrno; 1668 } 1669 if (newsock == -1) { 1670 if (errno != EINTR && errno != EWOULDBLOCK && 1671 errno != ECONNABORTED) 1672 error("accept: %.100s", strerror(errno)); 1673 if (errno == EMFILE || errno == ENFILE) 1674 c->notbefore = monotime() + 1; 1675 return; 1676 } 1677 set_nodelay(newsock); 1678 remote_ipaddr = get_peer_ipaddr(newsock); 1679 remote_port = get_peer_port(newsock); 1680 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1681 remote_ipaddr, remote_port); 1682 1683 nc = channel_new(ssh, "accepted x11 socket", 1684 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1685 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1686 open_preamble(ssh, __func__, nc, "x11"); 1687 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1688 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1689 fatal("%s: channel %i: reply %s", __func__, 1690 c->self, ssh_err(r)); 1691 } 1692 if ((r = sshpkt_send(ssh)) != 0) 1693 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); 1694 free(remote_ipaddr); 1695 } 1696 1697 static void 1698 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1699 { 1700 char *local_ipaddr = get_local_ipaddr(c->sock); 1701 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1702 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1703 int remote_port = get_peer_port(c->sock); 1704 int r; 1705 1706 if (remote_port == -1) { 1707 /* Fake addr/port to appease peers that validate it (Tectia) */ 1708 free(remote_ipaddr); 1709 remote_ipaddr = xstrdup("127.0.0.1"); 1710 remote_port = 65535; 1711 } 1712 1713 free(c->remote_name); 1714 xasprintf(&c->remote_name, 1715 "%s: listening port %d for %.100s port %d, " 1716 "connect from %.200s port %d to %.100s port %d", 1717 rtype, c->listening_port, c->path, c->host_port, 1718 remote_ipaddr, remote_port, local_ipaddr, local_port); 1719 1720 open_preamble(ssh, __func__, c, rtype); 1721 if (strcmp(rtype, "direct-tcpip") == 0) { 1722 /* target host, port */ 1723 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1724 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) { 1725 fatal("%s: channel %i: reply %s", __func__, 1726 c->self, ssh_err(r)); 1727 } 1728 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1729 /* target path */ 1730 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { 1731 fatal("%s: channel %i: reply %s", __func__, 1732 c->self, ssh_err(r)); 1733 } 1734 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1735 /* listen path */ 1736 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { 1737 fatal("%s: channel %i: reply %s", __func__, 1738 c->self, ssh_err(r)); 1739 } 1740 } else { 1741 /* listen address, port */ 1742 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1743 (r = sshpkt_put_u32(ssh, local_port)) != 0) { 1744 fatal("%s: channel %i: reply %s", __func__, 1745 c->self, ssh_err(r)); 1746 } 1747 } 1748 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1749 /* reserved for future owner/mode info */ 1750 if ((r = sshpkt_put_cstring(ssh, "")) != 0) { 1751 fatal("%s: channel %i: reply %s", __func__, 1752 c->self, ssh_err(r)); 1753 } 1754 } else { 1755 /* originator host and port */ 1756 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1757 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) { 1758 fatal("%s: channel %i: reply %s", __func__, 1759 c->self, ssh_err(r)); 1760 } 1761 } 1762 if ((r = sshpkt_send(ssh)) != 0) 1763 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); 1764 free(remote_ipaddr); 1765 free(local_ipaddr); 1766 } 1767 1768 void 1769 channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time) 1770 { 1771 ssh->chanctxt->x11_refuse_time = refuse_time; 1772 } 1773 1774 /* 1775 * This socket is listening for connections to a forwarded TCP/IP port. 1776 */ 1777 static void 1778 channel_post_port_listener(struct ssh *ssh, Channel *c, 1779 fd_set *readset, fd_set *writeset) 1780 { 1781 Channel *nc; 1782 struct sockaddr_storage addr; 1783 int newsock, nextstate; 1784 socklen_t addrlen; 1785 char *rtype; 1786 1787 if (!FD_ISSET(c->sock, readset)) 1788 return; 1789 1790 debug("Connection to port %d forwarding to %.100s port %d requested.", 1791 c->listening_port, c->path, c->host_port); 1792 1793 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1794 nextstate = SSH_CHANNEL_OPENING; 1795 rtype = "forwarded-tcpip"; 1796 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1797 nextstate = SSH_CHANNEL_OPENING; 1798 rtype = "forwarded-streamlocal@openssh.com"; 1799 } else if (c->host_port == PORT_STREAMLOCAL) { 1800 nextstate = SSH_CHANNEL_OPENING; 1801 rtype = "direct-streamlocal@openssh.com"; 1802 } else if (c->host_port == 0) { 1803 nextstate = SSH_CHANNEL_DYNAMIC; 1804 rtype = "dynamic-tcpip"; 1805 } else { 1806 nextstate = SSH_CHANNEL_OPENING; 1807 rtype = "direct-tcpip"; 1808 } 1809 1810 addrlen = sizeof(addr); 1811 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1812 if (newsock == -1) { 1813 if (errno != EINTR && errno != EWOULDBLOCK && 1814 errno != ECONNABORTED) 1815 error("accept: %.100s", strerror(errno)); 1816 if (errno == EMFILE || errno == ENFILE) 1817 c->notbefore = monotime() + 1; 1818 return; 1819 } 1820 if (c->host_port != PORT_STREAMLOCAL) 1821 set_nodelay(newsock); 1822 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1823 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1824 nc->listening_port = c->listening_port; 1825 nc->host_port = c->host_port; 1826 if (c->path != NULL) 1827 nc->path = xstrdup(c->path); 1828 1829 if (nextstate != SSH_CHANNEL_DYNAMIC) 1830 port_open_helper(ssh, nc, rtype); 1831 } 1832 1833 /* 1834 * This is the authentication agent socket listening for connections from 1835 * clients. 1836 */ 1837 static void 1838 channel_post_auth_listener(struct ssh *ssh, Channel *c, 1839 fd_set *readset, fd_set *writeset) 1840 { 1841 Channel *nc; 1842 int r, newsock; 1843 struct sockaddr_storage addr; 1844 socklen_t addrlen; 1845 1846 if (!FD_ISSET(c->sock, readset)) 1847 return; 1848 1849 addrlen = sizeof(addr); 1850 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1851 if (newsock == -1) { 1852 error("accept from auth socket: %.100s", strerror(errno)); 1853 if (errno == EMFILE || errno == ENFILE) 1854 c->notbefore = monotime() + 1; 1855 return; 1856 } 1857 nc = channel_new(ssh, "accepted auth socket", 1858 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1859 c->local_window_max, c->local_maxpacket, 1860 0, "accepted auth socket", 1); 1861 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1862 if ((r = sshpkt_send(ssh)) != 0) 1863 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 1864 } 1865 1866 static void 1867 channel_post_connecting(struct ssh *ssh, Channel *c, 1868 fd_set *readset, fd_set *writeset) 1869 { 1870 int err = 0, sock, isopen, r; 1871 socklen_t sz = sizeof(err); 1872 1873 if (!FD_ISSET(c->sock, writeset)) 1874 return; 1875 if (!c->have_remote_id) 1876 fatal(":%s: channel %d: no remote id", __func__, c->self); 1877 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1878 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1879 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 1880 err = errno; 1881 error("getsockopt SO_ERROR failed"); 1882 } 1883 if (err == 0) { 1884 debug("channel %d: connected to %s port %d", 1885 c->self, c->connect_ctx.host, c->connect_ctx.port); 1886 channel_connect_ctx_free(&c->connect_ctx); 1887 c->type = SSH_CHANNEL_OPEN; 1888 if (isopen) { 1889 /* no message necessary */ 1890 } else { 1891 if ((r = sshpkt_start(ssh, 1892 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1893 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1894 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1895 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1896 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) 1897 != 0) 1898 fatal("%s: channel %i: confirm: %s", __func__, 1899 c->self, ssh_err(r)); 1900 if ((r = sshpkt_send(ssh)) != 0) 1901 fatal("%s: channel %i: %s", __func__, c->self, 1902 ssh_err(r)); 1903 } 1904 } else { 1905 debug("channel %d: connection failed: %s", 1906 c->self, strerror(err)); 1907 /* Try next address, if any */ 1908 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1909 close(c->sock); 1910 c->sock = c->rfd = c->wfd = sock; 1911 channel_find_maxfd(ssh->chanctxt); 1912 return; 1913 } 1914 /* Exhausted all addresses */ 1915 error("connect_to %.100s port %d: failed.", 1916 c->connect_ctx.host, c->connect_ctx.port); 1917 channel_connect_ctx_free(&c->connect_ctx); 1918 if (isopen) { 1919 rdynamic_close(ssh, c); 1920 } else { 1921 if ((r = sshpkt_start(ssh, 1922 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1923 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1924 (r = sshpkt_put_u32(ssh, 1925 SSH2_OPEN_CONNECT_FAILED)) != 0 || 1926 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 1927 (r = sshpkt_put_cstring(ssh, "")) != 0) { 1928 fatal("%s: channel %i: failure: %s", __func__, 1929 c->self, ssh_err(r)); 1930 } 1931 if ((r = sshpkt_send(ssh)) != 0) 1932 fatal("%s: channel %i: %s", __func__, c->self, 1933 ssh_err(r)); 1934 chan_mark_dead(ssh, c); 1935 } 1936 } 1937 } 1938 1939 static int 1940 channel_handle_rfd(struct ssh *ssh, Channel *c, 1941 fd_set *readset, fd_set *writeset) 1942 { 1943 char buf[CHAN_RBUF]; 1944 ssize_t len; 1945 int r; 1946 1947 if (c->rfd == -1 || !FD_ISSET(c->rfd, readset)) 1948 return 1; 1949 1950 len = read(c->rfd, buf, sizeof(buf)); 1951 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 1952 return 1; 1953 if (len <= 0) { 1954 debug2("channel %d: read<=0 rfd %d len %zd", 1955 c->self, c->rfd, len); 1956 if (c->type != SSH_CHANNEL_OPEN) { 1957 debug2("channel %d: not open", c->self); 1958 chan_mark_dead(ssh, c); 1959 return -1; 1960 } else { 1961 chan_read_failed(ssh, c); 1962 } 1963 return -1; 1964 } 1965 if (c->input_filter != NULL) { 1966 if (c->input_filter(ssh, c, buf, len) == -1) { 1967 debug2("channel %d: filter stops", c->self); 1968 chan_read_failed(ssh, c); 1969 } 1970 } else if (c->datagram) { 1971 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 1972 fatal("%s: channel %d: put datagram: %s", __func__, 1973 c->self, ssh_err(r)); 1974 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { 1975 fatal("%s: channel %d: put data: %s", __func__, 1976 c->self, ssh_err(r)); 1977 } 1978 return 1; 1979 } 1980 1981 static int 1982 channel_handle_wfd(struct ssh *ssh, Channel *c, 1983 fd_set *readset, fd_set *writeset) 1984 { 1985 struct termios tio; 1986 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 1987 size_t dlen, olen = 0; 1988 int r, len; 1989 1990 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || 1991 sshbuf_len(c->output) == 0) 1992 return 1; 1993 1994 /* Send buffered output data to the socket. */ 1995 olen = sshbuf_len(c->output); 1996 if (c->output_filter != NULL) { 1997 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 1998 debug2("channel %d: filter stops", c->self); 1999 if (c->type != SSH_CHANNEL_OPEN) 2000 chan_mark_dead(ssh, c); 2001 else 2002 chan_write_failed(ssh, c); 2003 return -1; 2004 } 2005 } else if (c->datagram) { 2006 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2007 fatal("%s: channel %d: get datagram: %s", __func__, 2008 c->self, ssh_err(r)); 2009 buf = data; 2010 } else { 2011 buf = data = sshbuf_mutable_ptr(c->output); 2012 dlen = sshbuf_len(c->output); 2013 } 2014 2015 if (c->datagram) { 2016 /* ignore truncated writes, datagrams might get lost */ 2017 len = write(c->wfd, buf, dlen); 2018 free(data); 2019 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2020 return 1; 2021 if (len <= 0) 2022 goto write_fail; 2023 goto out; 2024 } 2025 2026 len = write(c->wfd, buf, dlen); 2027 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2028 return 1; 2029 if (len <= 0) { 2030 write_fail: 2031 if (c->type != SSH_CHANNEL_OPEN) { 2032 debug2("channel %d: not open", c->self); 2033 chan_mark_dead(ssh, c); 2034 return -1; 2035 } else { 2036 chan_write_failed(ssh, c); 2037 } 2038 return -1; 2039 } 2040 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2041 if (tcgetattr(c->wfd, &tio) == 0 && 2042 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2043 /* 2044 * Simulate echo to reduce the impact of 2045 * traffic analysis. We need to match the 2046 * size of a SSH2_MSG_CHANNEL_DATA message 2047 * (4 byte channel id + buf) 2048 */ 2049 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2050 (r = sshpkt_send(ssh)) != 0) 2051 fatal("%s: channel %d: ignore: %s", 2052 __func__, c->self, ssh_err(r)); 2053 } 2054 } 2055 if ((r = sshbuf_consume(c->output, len)) != 0) { 2056 fatal("%s: channel %d: consume: %s", 2057 __func__, c->self, ssh_err(r)); 2058 } 2059 out: 2060 c->local_consumed += olen - sshbuf_len(c->output); 2061 2062 return 1; 2063 } 2064 2065 static int 2066 channel_handle_efd_write(struct ssh *ssh, Channel *c, 2067 fd_set *readset, fd_set *writeset) 2068 { 2069 int r; 2070 ssize_t len; 2071 2072 if (!FD_ISSET(c->efd, writeset) || sshbuf_len(c->extended) == 0) 2073 return 1; 2074 2075 len = write(c->efd, sshbuf_ptr(c->extended), 2076 sshbuf_len(c->extended)); 2077 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2078 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2079 return 1; 2080 if (len <= 0) { 2081 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2082 channel_close_fd(ssh, &c->efd); 2083 } else { 2084 if ((r = sshbuf_consume(c->extended, len)) != 0) { 2085 fatal("%s: channel %d: consume: %s", 2086 __func__, c->self, ssh_err(r)); 2087 } 2088 c->local_consumed += len; 2089 } 2090 return 1; 2091 } 2092 2093 static int 2094 channel_handle_efd_read(struct ssh *ssh, Channel *c, 2095 fd_set *readset, fd_set *writeset) 2096 { 2097 char buf[CHAN_RBUF]; 2098 int r; 2099 ssize_t len; 2100 2101 if (!FD_ISSET(c->efd, readset)) 2102 return 1; 2103 2104 len = read(c->efd, buf, sizeof(buf)); 2105 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2106 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2107 return 1; 2108 if (len <= 0) { 2109 debug2("channel %d: closing read-efd %d", 2110 c->self, c->efd); 2111 channel_close_fd(ssh, &c->efd); 2112 } else { 2113 if (c->extended_usage == CHAN_EXTENDED_IGNORE) { 2114 debug3("channel %d: discard efd", 2115 c->self); 2116 } else if ((r = sshbuf_put(c->extended, buf, len)) != 0) { 2117 fatal("%s: channel %d: append: %s", 2118 __func__, c->self, ssh_err(r)); 2119 } 2120 } 2121 return 1; 2122 } 2123 2124 static int 2125 channel_handle_efd(struct ssh *ssh, Channel *c, 2126 fd_set *readset, fd_set *writeset) 2127 { 2128 if (c->efd == -1) 2129 return 1; 2130 2131 /** XXX handle drain efd, too */ 2132 2133 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2134 return channel_handle_efd_write(ssh, c, readset, writeset); 2135 else if (c->extended_usage == CHAN_EXTENDED_READ || 2136 c->extended_usage == CHAN_EXTENDED_IGNORE) 2137 return channel_handle_efd_read(ssh, c, readset, writeset); 2138 2139 return 1; 2140 } 2141 2142 static int 2143 channel_check_window(struct ssh *ssh, Channel *c) 2144 { 2145 int r; 2146 2147 if (c->type == SSH_CHANNEL_OPEN && 2148 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2149 ((c->local_window_max - c->local_window > 2150 c->local_maxpacket*3) || 2151 c->local_window < c->local_window_max/2) && 2152 c->local_consumed > 0) { 2153 if (!c->have_remote_id) 2154 fatal(":%s: channel %d: no remote id", 2155 __func__, c->self); 2156 if ((r = sshpkt_start(ssh, 2157 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2158 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2159 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2160 (r = sshpkt_send(ssh)) != 0) { 2161 fatal("%s: channel %i: %s", __func__, 2162 c->self, ssh_err(r)); 2163 } 2164 debug2("channel %d: window %d sent adjust %d", 2165 c->self, c->local_window, 2166 c->local_consumed); 2167 c->local_window += c->local_consumed; 2168 c->local_consumed = 0; 2169 } 2170 return 1; 2171 } 2172 2173 static void 2174 channel_post_open(struct ssh *ssh, Channel *c, 2175 fd_set *readset, fd_set *writeset) 2176 { 2177 channel_handle_rfd(ssh, c, readset, writeset); 2178 channel_handle_wfd(ssh, c, readset, writeset); 2179 channel_handle_efd(ssh, c, readset, writeset); 2180 channel_check_window(ssh, c); 2181 } 2182 2183 static u_int 2184 read_mux(struct ssh *ssh, Channel *c, u_int need) 2185 { 2186 char buf[CHAN_RBUF]; 2187 ssize_t len; 2188 u_int rlen; 2189 int r; 2190 2191 if (sshbuf_len(c->input) < need) { 2192 rlen = need - sshbuf_len(c->input); 2193 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2194 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2195 return sshbuf_len(c->input); 2196 if (len <= 0) { 2197 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2198 c->self, c->rfd, len); 2199 chan_read_failed(ssh, c); 2200 return 0; 2201 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { 2202 fatal("%s: channel %d: append: %s", 2203 __func__, c->self, ssh_err(r)); 2204 } 2205 } 2206 return sshbuf_len(c->input); 2207 } 2208 2209 static void 2210 channel_post_mux_client_read(struct ssh *ssh, Channel *c, 2211 fd_set *readset, fd_set *writeset) 2212 { 2213 u_int need; 2214 2215 if (c->rfd == -1 || !FD_ISSET(c->rfd, readset)) 2216 return; 2217 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2218 return; 2219 if (c->mux_pause) 2220 return; 2221 2222 /* 2223 * Don't not read past the precise end of packets to 2224 * avoid disrupting fd passing. 2225 */ 2226 if (read_mux(ssh, c, 4) < 4) /* read header */ 2227 return; 2228 /* XXX sshbuf_peek_u32 */ 2229 need = PEEK_U32(sshbuf_ptr(c->input)); 2230 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2231 if (need > CHANNEL_MUX_MAX_PACKET) { 2232 debug2("channel %d: packet too big %u > %u", 2233 c->self, CHANNEL_MUX_MAX_PACKET, need); 2234 chan_rcvd_oclose(ssh, c); 2235 return; 2236 } 2237 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2238 return; 2239 if (c->mux_rcb(ssh, c) != 0) { 2240 debug("channel %d: mux_rcb failed", c->self); 2241 chan_mark_dead(ssh, c); 2242 return; 2243 } 2244 } 2245 2246 static void 2247 channel_post_mux_client_write(struct ssh *ssh, Channel *c, 2248 fd_set *readset, fd_set *writeset) 2249 { 2250 ssize_t len; 2251 int r; 2252 2253 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || 2254 sshbuf_len(c->output) == 0) 2255 return; 2256 2257 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2258 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2259 return; 2260 if (len <= 0) { 2261 chan_mark_dead(ssh, c); 2262 return; 2263 } 2264 if ((r = sshbuf_consume(c->output, len)) != 0) 2265 fatal("%s: channel %d: consume: %s", __func__, 2266 c->self, ssh_err(r)); 2267 } 2268 2269 static void 2270 channel_post_mux_client(struct ssh *ssh, Channel *c, 2271 fd_set *readset, fd_set *writeset) 2272 { 2273 channel_post_mux_client_read(ssh, c, readset, writeset); 2274 channel_post_mux_client_write(ssh, c, readset, writeset); 2275 } 2276 2277 static void 2278 channel_post_mux_listener(struct ssh *ssh, Channel *c, 2279 fd_set *readset, fd_set *writeset) 2280 { 2281 Channel *nc; 2282 struct sockaddr_storage addr; 2283 socklen_t addrlen; 2284 int newsock; 2285 uid_t euid; 2286 gid_t egid; 2287 2288 if (!FD_ISSET(c->sock, readset)) 2289 return; 2290 2291 debug("multiplexing control connection"); 2292 2293 /* 2294 * Accept connection on control socket 2295 */ 2296 memset(&addr, 0, sizeof(addr)); 2297 addrlen = sizeof(addr); 2298 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2299 &addrlen)) == -1) { 2300 error("%s accept: %s", __func__, strerror(errno)); 2301 if (errno == EMFILE || errno == ENFILE) 2302 c->notbefore = monotime() + 1; 2303 return; 2304 } 2305 2306 if (getpeereid(newsock, &euid, &egid) == -1) { 2307 error("%s getpeereid failed: %s", __func__, 2308 strerror(errno)); 2309 close(newsock); 2310 return; 2311 } 2312 if ((euid != 0) && (getuid() != euid)) { 2313 error("multiplex uid mismatch: peer euid %u != uid %u", 2314 (u_int)euid, (u_int)getuid()); 2315 close(newsock); 2316 return; 2317 } 2318 nc = channel_new(ssh, "multiplex client", SSH_CHANNEL_MUX_CLIENT, 2319 newsock, newsock, -1, c->local_window_max, 2320 c->local_maxpacket, 0, "mux-control", 1); 2321 nc->mux_rcb = c->mux_rcb; 2322 debug3("%s: new mux channel %d fd %d", __func__, nc->self, nc->sock); 2323 /* establish state */ 2324 nc->mux_rcb(ssh, nc); 2325 /* mux state transitions must not elicit protocol messages */ 2326 nc->flags |= CHAN_LOCAL; 2327 } 2328 2329 static void 2330 channel_handler_init(struct ssh_channels *sc) 2331 { 2332 chan_fn **pre, **post; 2333 2334 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2335 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2336 fatal("%s: allocation failed", __func__); 2337 2338 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2339 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2340 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2341 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2342 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2343 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2344 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2345 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2346 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2347 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2348 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2349 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2350 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2351 2352 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2353 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2354 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2355 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2356 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2357 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2358 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2359 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2360 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2361 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2362 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2363 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2364 2365 sc->channel_pre = pre; 2366 sc->channel_post = post; 2367 } 2368 2369 /* gc dead channels */ 2370 static void 2371 channel_garbage_collect(struct ssh *ssh, Channel *c) 2372 { 2373 if (c == NULL) 2374 return; 2375 if (c->detach_user != NULL) { 2376 if (!chan_is_dead(ssh, c, c->detach_close)) 2377 return; 2378 2379 debug2("channel %d: gc: notify user", c->self); 2380 c->detach_user(ssh, c->self, NULL); 2381 /* if we still have a callback */ 2382 if (c->detach_user != NULL) 2383 return; 2384 debug2("channel %d: gc: user detached", c->self); 2385 } 2386 if (!chan_is_dead(ssh, c, 1)) 2387 return; 2388 debug2("channel %d: garbage collecting", c->self); 2389 channel_free(ssh, c); 2390 } 2391 2392 enum channel_table { CHAN_PRE, CHAN_POST }; 2393 2394 static void 2395 channel_handler(struct ssh *ssh, int table, 2396 fd_set *readset, fd_set *writeset, time_t *unpause_secs) 2397 { 2398 struct ssh_channels *sc = ssh->chanctxt; 2399 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2400 u_int i, oalloc; 2401 Channel *c; 2402 time_t now; 2403 2404 now = monotime(); 2405 if (unpause_secs != NULL) 2406 *unpause_secs = 0; 2407 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2408 c = sc->channels[i]; 2409 if (c == NULL) 2410 continue; 2411 if (c->delayed) { 2412 if (table == CHAN_PRE) 2413 c->delayed = 0; 2414 else 2415 continue; 2416 } 2417 if (ftab[c->type] != NULL) { 2418 /* 2419 * Run handlers that are not paused. 2420 */ 2421 if (c->notbefore <= now) 2422 (*ftab[c->type])(ssh, c, readset, writeset); 2423 else if (unpause_secs != NULL) { 2424 /* 2425 * Collect the time that the earliest 2426 * channel comes off pause. 2427 */ 2428 debug3("%s: chan %d: skip for %d more seconds", 2429 __func__, c->self, 2430 (int)(c->notbefore - now)); 2431 if (*unpause_secs == 0 || 2432 (c->notbefore - now) < *unpause_secs) 2433 *unpause_secs = c->notbefore - now; 2434 } 2435 } 2436 channel_garbage_collect(ssh, c); 2437 } 2438 if (unpause_secs != NULL && *unpause_secs != 0) 2439 debug3("%s: first channel unpauses in %d seconds", 2440 __func__, (int)*unpause_secs); 2441 } 2442 2443 /* 2444 * Create sockets before allocating the select bitmasks. 2445 * This is necessary for things that need to happen after reading 2446 * the network-input but before channel_prepare_select(). 2447 */ 2448 static void 2449 channel_before_prepare_select(struct ssh *ssh) 2450 { 2451 struct ssh_channels *sc = ssh->chanctxt; 2452 Channel *c; 2453 u_int i, oalloc; 2454 2455 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2456 c = sc->channels[i]; 2457 if (c == NULL) 2458 continue; 2459 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2460 channel_before_prepare_select_rdynamic(ssh, c); 2461 } 2462 } 2463 2464 /* 2465 * Allocate/update select bitmasks and add any bits relevant to channels in 2466 * select bitmasks. 2467 */ 2468 void 2469 channel_prepare_select(struct ssh *ssh, fd_set **readsetp, fd_set **writesetp, 2470 int *maxfdp, u_int *nallocp, time_t *minwait_secs) 2471 { 2472 u_int n, sz, nfdset; 2473 2474 channel_before_prepare_select(ssh); /* might update channel_max_fd */ 2475 2476 n = MAXIMUM(*maxfdp, ssh->chanctxt->channel_max_fd); 2477 2478 nfdset = howmany(n+1, NFDBITS); 2479 /* Explicitly test here, because xrealloc isn't always called */ 2480 if (nfdset && SIZE_MAX / nfdset < sizeof(fd_mask)) 2481 fatal("channel_prepare_select: max_fd (%d) is too large", n); 2482 sz = nfdset * sizeof(fd_mask); 2483 2484 /* perhaps check sz < nalloc/2 and shrink? */ 2485 if (*readsetp == NULL || sz > *nallocp) { 2486 *readsetp = xreallocarray(*readsetp, nfdset, sizeof(fd_mask)); 2487 *writesetp = xreallocarray(*writesetp, nfdset, sizeof(fd_mask)); 2488 *nallocp = sz; 2489 } 2490 *maxfdp = n; 2491 memset(*readsetp, 0, sz); 2492 memset(*writesetp, 0, sz); 2493 2494 if (!ssh_packet_is_rekeying(ssh)) 2495 channel_handler(ssh, CHAN_PRE, *readsetp, *writesetp, 2496 minwait_secs); 2497 } 2498 2499 /* 2500 * After select, perform any appropriate operations for channels which have 2501 * events pending. 2502 */ 2503 void 2504 channel_after_select(struct ssh *ssh, fd_set *readset, fd_set *writeset) 2505 { 2506 channel_handler(ssh, CHAN_POST, readset, writeset, NULL); 2507 } 2508 2509 /* 2510 * Enqueue data for channels with open or draining c->input. 2511 */ 2512 static void 2513 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2514 { 2515 size_t len, plen; 2516 const u_char *pkt; 2517 int r; 2518 2519 if ((len = sshbuf_len(c->input)) == 0) { 2520 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2521 /* 2522 * input-buffer is empty and read-socket shutdown: 2523 * tell peer, that we will not send more data: 2524 * send IEOF. 2525 * hack for extended data: delay EOF if EFD still 2526 * in use. 2527 */ 2528 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2529 debug2("channel %d: " 2530 "ibuf_empty delayed efd %d/(%zu)", 2531 c->self, c->efd, sshbuf_len(c->extended)); 2532 else 2533 chan_ibuf_empty(ssh, c); 2534 } 2535 return; 2536 } 2537 2538 if (!c->have_remote_id) 2539 fatal(":%s: channel %d: no remote id", __func__, c->self); 2540 2541 if (c->datagram) { 2542 /* Check datagram will fit; drop if not */ 2543 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2544 fatal("%s: channel %d: get datagram: %s", __func__, 2545 c->self, ssh_err(r)); 2546 /* 2547 * XXX this does tail-drop on the datagram queue which is 2548 * usually suboptimal compared to head-drop. Better to have 2549 * backpressure at read time? (i.e. read + discard) 2550 */ 2551 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2552 debug("channel %d: datagram too big", c->self); 2553 return; 2554 } 2555 /* Enqueue it */ 2556 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2557 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2558 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2559 (r = sshpkt_send(ssh)) != 0) { 2560 fatal("%s: channel %i: datagram: %s", __func__, 2561 c->self, ssh_err(r)); 2562 } 2563 c->remote_window -= plen; 2564 return; 2565 } 2566 2567 /* Enqueue packet for buffered data. */ 2568 if (len > c->remote_window) 2569 len = c->remote_window; 2570 if (len > c->remote_maxpacket) 2571 len = c->remote_maxpacket; 2572 if (len == 0) 2573 return; 2574 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2575 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2576 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2577 (r = sshpkt_send(ssh)) != 0) { 2578 fatal("%s: channel %i: data: %s", __func__, 2579 c->self, ssh_err(r)); 2580 } 2581 if ((r = sshbuf_consume(c->input, len)) != 0) 2582 fatal("%s: channel %i: consume: %s", __func__, 2583 c->self, ssh_err(r)); 2584 c->remote_window -= len; 2585 } 2586 2587 /* 2588 * Enqueue data for channels with open c->extended in read mode. 2589 */ 2590 static void 2591 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2592 { 2593 size_t len; 2594 int r; 2595 2596 if ((len = sshbuf_len(c->extended)) == 0) 2597 return; 2598 2599 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2600 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2601 if (len > c->remote_window) 2602 len = c->remote_window; 2603 if (len > c->remote_maxpacket) 2604 len = c->remote_maxpacket; 2605 if (len == 0) 2606 return; 2607 if (!c->have_remote_id) 2608 fatal(":%s: channel %d: no remote id", __func__, c->self); 2609 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2610 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2611 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2612 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2613 (r = sshpkt_send(ssh)) != 0) { 2614 fatal("%s: channel %i: data: %s", __func__, 2615 c->self, ssh_err(r)); 2616 } 2617 if ((r = sshbuf_consume(c->extended, len)) != 0) 2618 fatal("%s: channel %i: consume: %s", __func__, 2619 c->self, ssh_err(r)); 2620 c->remote_window -= len; 2621 debug2("channel %d: sent ext data %zu", c->self, len); 2622 } 2623 2624 /* If there is data to send to the connection, enqueue some of it now. */ 2625 void 2626 channel_output_poll(struct ssh *ssh) 2627 { 2628 struct ssh_channels *sc = ssh->chanctxt; 2629 Channel *c; 2630 u_int i; 2631 2632 for (i = 0; i < sc->channels_alloc; i++) { 2633 c = sc->channels[i]; 2634 if (c == NULL) 2635 continue; 2636 2637 /* 2638 * We are only interested in channels that can have buffered 2639 * incoming data. 2640 */ 2641 if (c->type != SSH_CHANNEL_OPEN) 2642 continue; 2643 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2644 /* XXX is this true? */ 2645 debug3("channel %d: will not send data after close", 2646 c->self); 2647 continue; 2648 } 2649 2650 /* Get the amount of buffered data for this channel. */ 2651 if (c->istate == CHAN_INPUT_OPEN || 2652 c->istate == CHAN_INPUT_WAIT_DRAIN) 2653 channel_output_poll_input_open(ssh, c); 2654 /* Send extended data, i.e. stderr */ 2655 if (!(c->flags & CHAN_EOF_SENT) && 2656 c->extended_usage == CHAN_EXTENDED_READ) 2657 channel_output_poll_extended_read(ssh, c); 2658 } 2659 } 2660 2661 /* -- mux proxy support */ 2662 2663 /* 2664 * When multiplexing channel messages for mux clients we have to deal 2665 * with downstream messages from the mux client and upstream messages 2666 * from the ssh server: 2667 * 1) Handling downstream messages is straightforward and happens 2668 * in channel_proxy_downstream(): 2669 * - We forward all messages (mostly) unmodified to the server. 2670 * - However, in order to route messages from upstream to the correct 2671 * downstream client, we have to replace the channel IDs used by the 2672 * mux clients with a unique channel ID because the mux clients might 2673 * use conflicting channel IDs. 2674 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 2675 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 2676 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 2677 * with the newly allocated channel ID. 2678 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 2679 * channels and processed by channel_proxy_upstream(). The local channel ID 2680 * is then translated back to the original mux client ID. 2681 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 2682 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 2683 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 2684 * downstream mux client are removed. 2685 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 2686 * requires more work, because they are not addressed to a specific 2687 * channel. E.g. client_request_forwarded_tcpip() needs to figure 2688 * out whether the request is addressed to the local client or a 2689 * specific downstream client based on the listen-address/port. 2690 * 6) Agent and X11-Forwarding have a similar problem and are currently 2691 * not supported as the matching session/channel cannot be identified 2692 * easily. 2693 */ 2694 2695 /* 2696 * receive packets from downstream mux clients: 2697 * channel callback fired on read from mux client, creates 2698 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 2699 * on channel creation. 2700 */ 2701 int 2702 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 2703 { 2704 Channel *c = NULL; 2705 struct sshbuf *original = NULL, *modified = NULL; 2706 const u_char *cp; 2707 char *ctype = NULL, *listen_host = NULL; 2708 u_char type; 2709 size_t have; 2710 int ret = -1, r; 2711 u_int id, remote_id, listen_port; 2712 2713 /* sshbuf_dump(downstream->input, stderr); */ 2714 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 2715 != 0) { 2716 error("%s: malformed message: %s", __func__, ssh_err(r)); 2717 return -1; 2718 } 2719 if (have < 2) { 2720 error("%s: short message", __func__); 2721 return -1; 2722 } 2723 type = cp[1]; 2724 /* skip padlen + type */ 2725 cp += 2; 2726 have -= 2; 2727 if (ssh_packet_log_type(type)) 2728 debug3("%s: channel %u: down->up: type %u", __func__, 2729 downstream->self, type); 2730 2731 switch (type) { 2732 case SSH2_MSG_CHANNEL_OPEN: 2733 if ((original = sshbuf_from(cp, have)) == NULL || 2734 (modified = sshbuf_new()) == NULL) { 2735 error("%s: alloc", __func__); 2736 goto out; 2737 } 2738 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 2739 (r = sshbuf_get_u32(original, &id)) != 0) { 2740 error("%s: parse error %s", __func__, ssh_err(r)); 2741 goto out; 2742 } 2743 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2744 -1, -1, -1, 0, 0, 0, ctype, 1); 2745 c->mux_ctx = downstream; /* point to mux client */ 2746 c->mux_downstream_id = id; /* original downstream id */ 2747 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 2748 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2749 (r = sshbuf_putb(modified, original)) != 0) { 2750 error("%s: compose error %s", __func__, ssh_err(r)); 2751 channel_free(ssh, c); 2752 goto out; 2753 } 2754 break; 2755 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2756 /* 2757 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 2758 * need to parse 'remote_id' instead of 'ctype'. 2759 */ 2760 if ((original = sshbuf_from(cp, have)) == NULL || 2761 (modified = sshbuf_new()) == NULL) { 2762 error("%s: alloc", __func__); 2763 goto out; 2764 } 2765 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 2766 (r = sshbuf_get_u32(original, &id)) != 0) { 2767 error("%s: parse error %s", __func__, ssh_err(r)); 2768 goto out; 2769 } 2770 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2771 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 2772 c->mux_ctx = downstream; /* point to mux client */ 2773 c->mux_downstream_id = id; 2774 c->remote_id = remote_id; 2775 c->have_remote_id = 1; 2776 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 2777 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2778 (r = sshbuf_putb(modified, original)) != 0) { 2779 error("%s: compose error %s", __func__, ssh_err(r)); 2780 channel_free(ssh, c); 2781 goto out; 2782 } 2783 break; 2784 case SSH2_MSG_GLOBAL_REQUEST: 2785 if ((original = sshbuf_from(cp, have)) == NULL) { 2786 error("%s: alloc", __func__); 2787 goto out; 2788 } 2789 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 2790 error("%s: parse error %s", __func__, ssh_err(r)); 2791 goto out; 2792 } 2793 if (strcmp(ctype, "tcpip-forward") != 0) { 2794 error("%s: unsupported request %s", __func__, ctype); 2795 goto out; 2796 } 2797 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 2798 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 2799 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 2800 error("%s: parse error %s", __func__, ssh_err(r)); 2801 goto out; 2802 } 2803 if (listen_port > 65535) { 2804 error("%s: tcpip-forward for %s: bad port %u", 2805 __func__, listen_host, listen_port); 2806 goto out; 2807 } 2808 /* Record that connection to this host/port is permitted. */ 2809 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 2810 listen_host, NULL, (int)listen_port, downstream); 2811 listen_host = NULL; 2812 break; 2813 case SSH2_MSG_CHANNEL_CLOSE: 2814 if (have < 4) 2815 break; 2816 remote_id = PEEK_U32(cp); 2817 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 2818 if (c->flags & CHAN_CLOSE_RCVD) 2819 channel_free(ssh, c); 2820 else 2821 c->flags |= CHAN_CLOSE_SENT; 2822 } 2823 break; 2824 } 2825 if (modified) { 2826 if ((r = sshpkt_start(ssh, type)) != 0 || 2827 (r = sshpkt_putb(ssh, modified)) != 0 || 2828 (r = sshpkt_send(ssh)) != 0) { 2829 error("%s: send %s", __func__, ssh_err(r)); 2830 goto out; 2831 } 2832 } else { 2833 if ((r = sshpkt_start(ssh, type)) != 0 || 2834 (r = sshpkt_put(ssh, cp, have)) != 0 || 2835 (r = sshpkt_send(ssh)) != 0) { 2836 error("%s: send %s", __func__, ssh_err(r)); 2837 goto out; 2838 } 2839 } 2840 ret = 0; 2841 out: 2842 free(ctype); 2843 free(listen_host); 2844 sshbuf_free(original); 2845 sshbuf_free(modified); 2846 return ret; 2847 } 2848 2849 /* 2850 * receive packets from upstream server and de-multiplex packets 2851 * to correct downstream: 2852 * implemented as a helper for channel input handlers, 2853 * replaces local (proxy) channel ID with downstream channel ID. 2854 */ 2855 int 2856 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 2857 { 2858 struct sshbuf *b = NULL; 2859 Channel *downstream; 2860 const u_char *cp = NULL; 2861 size_t len; 2862 int r; 2863 2864 /* 2865 * When receiving packets from the peer we need to check whether we 2866 * need to forward the packets to the mux client. In this case we 2867 * restore the original channel id and keep track of CLOSE messages, 2868 * so we can cleanup the channel. 2869 */ 2870 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 2871 return 0; 2872 if ((downstream = c->mux_ctx) == NULL) 2873 return 0; 2874 switch (type) { 2875 case SSH2_MSG_CHANNEL_CLOSE: 2876 case SSH2_MSG_CHANNEL_DATA: 2877 case SSH2_MSG_CHANNEL_EOF: 2878 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 2879 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2880 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 2881 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 2882 case SSH2_MSG_CHANNEL_SUCCESS: 2883 case SSH2_MSG_CHANNEL_FAILURE: 2884 case SSH2_MSG_CHANNEL_REQUEST: 2885 break; 2886 default: 2887 debug2("%s: channel %u: unsupported type %u", __func__, 2888 c->self, type); 2889 return 0; 2890 } 2891 if ((b = sshbuf_new()) == NULL) { 2892 error("%s: alloc reply", __func__); 2893 goto out; 2894 } 2895 /* get remaining payload (after id) */ 2896 cp = sshpkt_ptr(ssh, &len); 2897 if (cp == NULL) { 2898 error("%s: no packet", __func__); 2899 goto out; 2900 } 2901 /* translate id and send to muxclient */ 2902 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 2903 (r = sshbuf_put_u8(b, type)) != 0 || 2904 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 2905 (r = sshbuf_put(b, cp, len)) != 0 || 2906 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 2907 error("%s: compose for muxclient %s", __func__, ssh_err(r)); 2908 goto out; 2909 } 2910 /* sshbuf_dump(b, stderr); */ 2911 if (ssh_packet_log_type(type)) 2912 debug3("%s: channel %u: up->down: type %u", __func__, c->self, 2913 type); 2914 out: 2915 /* update state */ 2916 switch (type) { 2917 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2918 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 2919 if (cp && len > 4) { 2920 c->remote_id = PEEK_U32(cp); 2921 c->have_remote_id = 1; 2922 } 2923 break; 2924 case SSH2_MSG_CHANNEL_CLOSE: 2925 if (c->flags & CHAN_CLOSE_SENT) 2926 channel_free(ssh, c); 2927 else 2928 c->flags |= CHAN_CLOSE_RCVD; 2929 break; 2930 } 2931 sshbuf_free(b); 2932 return 1; 2933 } 2934 2935 /* -- protocol input */ 2936 2937 /* Parse a channel ID from the current packet */ 2938 static int 2939 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 2940 { 2941 u_int32_t id; 2942 int r; 2943 2944 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 2945 error("%s: parse id: %s", where, ssh_err(r)); 2946 ssh_packet_disconnect(ssh, "Invalid %s message", what); 2947 } 2948 if (id > INT_MAX) { 2949 error("%s: bad channel id %u: %s", where, id, ssh_err(r)); 2950 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 2951 } 2952 return (int)id; 2953 } 2954 2955 /* Lookup a channel from an ID in the current packet */ 2956 static Channel * 2957 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 2958 { 2959 int id = channel_parse_id(ssh, where, what); 2960 Channel *c; 2961 2962 if ((c = channel_lookup(ssh, id)) == NULL) { 2963 ssh_packet_disconnect(ssh, 2964 "%s packet referred to nonexistent channel %d", what, id); 2965 } 2966 return c; 2967 } 2968 2969 int 2970 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 2971 { 2972 const u_char *data; 2973 size_t data_len, win_len; 2974 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 2975 int r; 2976 2977 if (channel_proxy_upstream(c, type, seq, ssh)) 2978 return 0; 2979 2980 /* Ignore any data for non-open channels (might happen on close) */ 2981 if (c->type != SSH_CHANNEL_OPEN && 2982 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 2983 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 2984 c->type != SSH_CHANNEL_X11_OPEN) 2985 return 0; 2986 2987 /* Get the data. */ 2988 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 2989 (r = sshpkt_get_end(ssh)) != 0) 2990 fatal("%s: channel %d: get data: %s", __func__, 2991 c->self, ssh_err(r)); 2992 2993 win_len = data_len; 2994 if (c->datagram) 2995 win_len += 4; /* string length header */ 2996 2997 /* 2998 * The sending side reduces its window as it sends data, so we 2999 * must 'fake' consumption of the data in order to ensure that window 3000 * updates are sent back. Otherwise the connection might deadlock. 3001 */ 3002 if (c->ostate != CHAN_OUTPUT_OPEN) { 3003 c->local_window -= win_len; 3004 c->local_consumed += win_len; 3005 return 0; 3006 } 3007 3008 if (win_len > c->local_maxpacket) { 3009 logit("channel %d: rcvd big packet %zu, maxpack %u", 3010 c->self, win_len, c->local_maxpacket); 3011 return 0; 3012 } 3013 if (win_len > c->local_window) { 3014 logit("channel %d: rcvd too much data %zu, win %u", 3015 c->self, win_len, c->local_window); 3016 return 0; 3017 } 3018 c->local_window -= win_len; 3019 3020 if (c->datagram) { 3021 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3022 fatal("%s: channel %d: append datagram: %s", 3023 __func__, c->self, ssh_err(r)); 3024 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3025 fatal("%s: channel %d: append data: %s", 3026 __func__, c->self, ssh_err(r)); 3027 3028 return 0; 3029 } 3030 3031 int 3032 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3033 { 3034 const u_char *data; 3035 size_t data_len; 3036 u_int32_t tcode; 3037 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3038 int r; 3039 3040 if (channel_proxy_upstream(c, type, seq, ssh)) 3041 return 0; 3042 if (c->type != SSH_CHANNEL_OPEN) { 3043 logit("channel %d: ext data for non open", c->self); 3044 return 0; 3045 } 3046 if (c->flags & CHAN_EOF_RCVD) { 3047 if (datafellows & SSH_BUG_EXTEOF) 3048 debug("channel %d: accepting ext data after eof", 3049 c->self); 3050 else 3051 ssh_packet_disconnect(ssh, "Received extended_data " 3052 "after EOF on channel %d.", c->self); 3053 } 3054 3055 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3056 error("%s: parse tcode: %s", __func__, ssh_err(r)); 3057 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3058 } 3059 if (c->efd == -1 || 3060 c->extended_usage != CHAN_EXTENDED_WRITE || 3061 tcode != SSH2_EXTENDED_DATA_STDERR) { 3062 logit("channel %d: bad ext data", c->self); 3063 return 0; 3064 } 3065 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3066 (r = sshpkt_get_end(ssh)) != 0) { 3067 error("%s: parse data: %s", __func__, ssh_err(r)); 3068 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3069 } 3070 3071 if (data_len > c->local_window) { 3072 logit("channel %d: rcvd too much extended_data %zu, win %u", 3073 c->self, data_len, c->local_window); 3074 return 0; 3075 } 3076 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3077 /* XXX sshpkt_getb? */ 3078 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3079 error("%s: append: %s", __func__, ssh_err(r)); 3080 c->local_window -= data_len; 3081 return 0; 3082 } 3083 3084 int 3085 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3086 { 3087 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3088 int r; 3089 3090 if ((r = sshpkt_get_end(ssh)) != 0) { 3091 error("%s: parse data: %s", __func__, ssh_err(r)); 3092 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3093 } 3094 3095 if (channel_proxy_upstream(c, type, seq, ssh)) 3096 return 0; 3097 chan_rcvd_ieof(ssh, c); 3098 3099 /* XXX force input close */ 3100 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3101 debug("channel %d: FORCE input drain", c->self); 3102 c->istate = CHAN_INPUT_WAIT_DRAIN; 3103 if (sshbuf_len(c->input) == 0) 3104 chan_ibuf_empty(ssh, c); 3105 } 3106 return 0; 3107 } 3108 3109 int 3110 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3111 { 3112 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3113 int r; 3114 3115 if (channel_proxy_upstream(c, type, seq, ssh)) 3116 return 0; 3117 if ((r = sshpkt_get_end(ssh)) != 0) { 3118 error("%s: parse data: %s", __func__, ssh_err(r)); 3119 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3120 } 3121 chan_rcvd_oclose(ssh, c); 3122 return 0; 3123 } 3124 3125 int 3126 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3127 { 3128 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3129 u_int32_t remote_window, remote_maxpacket; 3130 int r; 3131 3132 if (channel_proxy_upstream(c, type, seq, ssh)) 3133 return 0; 3134 if (c->type != SSH_CHANNEL_OPENING) 3135 ssh_packet_disconnect(ssh, "Received open confirmation for " 3136 "non-opening channel %d.", c->self); 3137 /* 3138 * Record the remote channel number and mark that the channel 3139 * is now open. 3140 */ 3141 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3142 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3143 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3144 (r = sshpkt_get_end(ssh)) != 0) { 3145 error("%s: window/maxpacket: %s", __func__, ssh_err(r)); 3146 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3147 } 3148 3149 c->have_remote_id = 1; 3150 c->remote_window = remote_window; 3151 c->remote_maxpacket = remote_maxpacket; 3152 c->type = SSH_CHANNEL_OPEN; 3153 if (c->open_confirm) { 3154 debug2("%s: channel %d: callback start", __func__, c->self); 3155 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3156 debug2("%s: channel %d: callback done", __func__, c->self); 3157 } 3158 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3159 c->remote_window, c->remote_maxpacket); 3160 return 0; 3161 } 3162 3163 static char * 3164 reason2txt(int reason) 3165 { 3166 switch (reason) { 3167 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3168 return "administratively prohibited"; 3169 case SSH2_OPEN_CONNECT_FAILED: 3170 return "connect failed"; 3171 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3172 return "unknown channel type"; 3173 case SSH2_OPEN_RESOURCE_SHORTAGE: 3174 return "resource shortage"; 3175 } 3176 return "unknown reason"; 3177 } 3178 3179 int 3180 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3181 { 3182 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3183 u_int32_t reason; 3184 char *msg = NULL; 3185 int r; 3186 3187 if (channel_proxy_upstream(c, type, seq, ssh)) 3188 return 0; 3189 if (c->type != SSH_CHANNEL_OPENING) 3190 ssh_packet_disconnect(ssh, "Received open failure for " 3191 "non-opening channel %d.", c->self); 3192 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3193 error("%s: reason: %s", __func__, ssh_err(r)); 3194 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3195 } 3196 /* skip language */ 3197 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3198 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3199 (r = sshpkt_get_end(ssh)) != 0) { 3200 error("%s: message/lang: %s", __func__, ssh_err(r)); 3201 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3202 } 3203 logit("channel %d: open failed: %s%s%s", c->self, 3204 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3205 free(msg); 3206 if (c->open_confirm) { 3207 debug2("%s: channel %d: callback start", __func__, c->self); 3208 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3209 debug2("%s: channel %d: callback done", __func__, c->self); 3210 } 3211 /* Schedule the channel for cleanup/deletion. */ 3212 chan_mark_dead(ssh, c); 3213 return 0; 3214 } 3215 3216 int 3217 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3218 { 3219 int id = channel_parse_id(ssh, __func__, "window adjust"); 3220 Channel *c; 3221 u_int32_t adjust; 3222 u_int new_rwin; 3223 int r; 3224 3225 if ((c = channel_lookup(ssh, id)) == NULL) { 3226 logit("Received window adjust for non-open channel %d.", id); 3227 return 0; 3228 } 3229 3230 if (channel_proxy_upstream(c, type, seq, ssh)) 3231 return 0; 3232 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3233 (r = sshpkt_get_end(ssh)) != 0) { 3234 error("%s: adjust: %s", __func__, ssh_err(r)); 3235 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3236 } 3237 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3238 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3239 fatal("channel %d: adjust %u overflows remote window %u", 3240 c->self, adjust, c->remote_window); 3241 } 3242 c->remote_window = new_rwin; 3243 return 0; 3244 } 3245 3246 int 3247 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3248 { 3249 int id = channel_parse_id(ssh, __func__, "status confirm"); 3250 Channel *c; 3251 struct channel_confirm *cc; 3252 3253 /* Reset keepalive timeout */ 3254 ssh_packet_set_alive_timeouts(ssh, 0); 3255 3256 debug2("%s: type %d id %d", __func__, type, id); 3257 3258 if ((c = channel_lookup(ssh, id)) == NULL) { 3259 logit("%s: %d: unknown", __func__, id); 3260 return 0; 3261 } 3262 if (channel_proxy_upstream(c, type, seq, ssh)) 3263 return 0; 3264 if (sshpkt_get_end(ssh) != 0) 3265 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3266 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3267 return 0; 3268 cc->cb(ssh, type, c, cc->ctx); 3269 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3270 freezero(cc, sizeof(*cc)); 3271 return 0; 3272 } 3273 3274 /* -- tcp forwarding */ 3275 3276 void 3277 channel_set_af(struct ssh *ssh, int af) 3278 { 3279 ssh->chanctxt->IPv4or6 = af; 3280 } 3281 3282 3283 /* 3284 * Determine whether or not a port forward listens to loopback, the 3285 * specified address or wildcard. On the client, a specified bind 3286 * address will always override gateway_ports. On the server, a 3287 * gateway_ports of 1 (``yes'') will override the client's specification 3288 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3289 * will bind to whatever address the client asked for. 3290 * 3291 * Special-case listen_addrs are: 3292 * 3293 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3294 * "" (empty string), "*" -> wildcard v4/v6 3295 * "localhost" -> loopback v4/v6 3296 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3297 */ 3298 static const char * 3299 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3300 int is_client, struct ForwardOptions *fwd_opts) 3301 { 3302 const char *addr = NULL; 3303 int wildcard = 0; 3304 3305 if (listen_addr == NULL) { 3306 /* No address specified: default to gateway_ports setting */ 3307 if (fwd_opts->gateway_ports) 3308 wildcard = 1; 3309 } else if (fwd_opts->gateway_ports || is_client) { 3310 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 3311 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3312 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3313 (!is_client && fwd_opts->gateway_ports == 1)) { 3314 wildcard = 1; 3315 /* 3316 * Notify client if they requested a specific listen 3317 * address and it was overridden. 3318 */ 3319 if (*listen_addr != '\0' && 3320 strcmp(listen_addr, "0.0.0.0") != 0 && 3321 strcmp(listen_addr, "*") != 0) { 3322 ssh_packet_send_debug(ssh, 3323 "Forwarding listen address " 3324 "\"%s\" overridden by server " 3325 "GatewayPorts", listen_addr); 3326 } 3327 } else if (strcmp(listen_addr, "localhost") != 0 || 3328 strcmp(listen_addr, "127.0.0.1") == 0 || 3329 strcmp(listen_addr, "::1") == 0) { 3330 /* 3331 * Accept explicit localhost address when 3332 * GatewayPorts=yes. The "localhost" hostname is 3333 * deliberately skipped here so it will listen on all 3334 * available local address families. 3335 */ 3336 addr = listen_addr; 3337 } 3338 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3339 strcmp(listen_addr, "::1") == 0) { 3340 /* 3341 * If a specific IPv4/IPv6 localhost address has been 3342 * requested then accept it even if gateway_ports is in 3343 * effect. This allows the client to prefer IPv4 or IPv6. 3344 */ 3345 addr = listen_addr; 3346 } 3347 if (wildcardp != NULL) 3348 *wildcardp = wildcard; 3349 return addr; 3350 } 3351 3352 static int 3353 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3354 struct Forward *fwd, int *allocated_listen_port, 3355 struct ForwardOptions *fwd_opts) 3356 { 3357 Channel *c; 3358 int sock, r, success = 0, wildcard = 0, is_client; 3359 struct addrinfo hints, *ai, *aitop; 3360 const char *host, *addr; 3361 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3362 in_port_t *lport_p; 3363 3364 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3365 3366 if (is_client && fwd->connect_path != NULL) { 3367 host = fwd->connect_path; 3368 } else { 3369 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3370 fwd->listen_host : fwd->connect_host; 3371 if (host == NULL) { 3372 error("No forward host name."); 3373 return 0; 3374 } 3375 if (strlen(host) >= NI_MAXHOST) { 3376 error("Forward host name too long."); 3377 return 0; 3378 } 3379 } 3380 3381 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3382 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3383 is_client, fwd_opts); 3384 debug3("%s: type %d wildcard %d addr %s", __func__, 3385 type, wildcard, (addr == NULL) ? "NULL" : addr); 3386 3387 /* 3388 * getaddrinfo returns a loopback address if the hostname is 3389 * set to NULL and hints.ai_flags is not AI_PASSIVE 3390 */ 3391 memset(&hints, 0, sizeof(hints)); 3392 hints.ai_family = ssh->chanctxt->IPv4or6; 3393 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3394 hints.ai_socktype = SOCK_STREAM; 3395 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3396 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3397 if (addr == NULL) { 3398 /* This really shouldn't happen */ 3399 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3400 ssh_gai_strerror(r)); 3401 } else { 3402 error("%s: getaddrinfo(%.64s): %s", __func__, addr, 3403 ssh_gai_strerror(r)); 3404 } 3405 return 0; 3406 } 3407 if (allocated_listen_port != NULL) 3408 *allocated_listen_port = 0; 3409 for (ai = aitop; ai; ai = ai->ai_next) { 3410 switch (ai->ai_family) { 3411 case AF_INET: 3412 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3413 sin_port; 3414 break; 3415 case AF_INET6: 3416 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3417 sin6_port; 3418 break; 3419 default: 3420 continue; 3421 } 3422 /* 3423 * If allocating a port for -R forwards, then use the 3424 * same port for all address families. 3425 */ 3426 if (type == SSH_CHANNEL_RPORT_LISTENER && 3427 fwd->listen_port == 0 && allocated_listen_port != NULL && 3428 *allocated_listen_port > 0) 3429 *lport_p = htons(*allocated_listen_port); 3430 3431 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3432 strport, sizeof(strport), 3433 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3434 error("%s: getnameinfo failed", __func__); 3435 continue; 3436 } 3437 /* Create a port to listen for the host. */ 3438 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3439 if (sock == -1) { 3440 /* this is no error since kernel may not support ipv6 */ 3441 verbose("socket [%s]:%s: %.100s", ntop, strport, 3442 strerror(errno)); 3443 continue; 3444 } 3445 3446 set_reuseaddr(sock); 3447 3448 debug("Local forwarding listening on %s port %s.", 3449 ntop, strport); 3450 3451 /* Bind the socket to the address. */ 3452 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3453 /* 3454 * address can be in if use ipv6 address is 3455 * already bound 3456 */ 3457 verbose("bind [%s]:%s: %.100s", 3458 ntop, strport, strerror(errno)); 3459 close(sock); 3460 continue; 3461 } 3462 /* Start listening for connections on the socket. */ 3463 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3464 error("listen [%s]:%s: %.100s", ntop, strport, 3465 strerror(errno)); 3466 close(sock); 3467 continue; 3468 } 3469 3470 /* 3471 * fwd->listen_port == 0 requests a dynamically allocated port - 3472 * record what we got. 3473 */ 3474 if (type == SSH_CHANNEL_RPORT_LISTENER && 3475 fwd->listen_port == 0 && 3476 allocated_listen_port != NULL && 3477 *allocated_listen_port == 0) { 3478 *allocated_listen_port = get_local_port(sock); 3479 debug("Allocated listen port %d", 3480 *allocated_listen_port); 3481 } 3482 3483 /* Allocate a channel number for the socket. */ 3484 c = channel_new(ssh, "port listener", type, sock, sock, -1, 3485 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3486 0, "port listener", 1); 3487 c->path = xstrdup(host); 3488 c->host_port = fwd->connect_port; 3489 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3490 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3491 !(datafellows & SSH_BUG_DYNAMIC_RPORT)) 3492 c->listening_port = *allocated_listen_port; 3493 else 3494 c->listening_port = fwd->listen_port; 3495 success = 1; 3496 } 3497 if (success == 0) 3498 error("%s: cannot listen to port: %d", __func__, 3499 fwd->listen_port); 3500 freeaddrinfo(aitop); 3501 return success; 3502 } 3503 3504 static int 3505 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3506 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3507 { 3508 struct sockaddr_un sunaddr; 3509 const char *path; 3510 Channel *c; 3511 int port, sock; 3512 mode_t omask; 3513 3514 switch (type) { 3515 case SSH_CHANNEL_UNIX_LISTENER: 3516 if (fwd->connect_path != NULL) { 3517 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3518 error("Local connecting path too long: %s", 3519 fwd->connect_path); 3520 return 0; 3521 } 3522 path = fwd->connect_path; 3523 port = PORT_STREAMLOCAL; 3524 } else { 3525 if (fwd->connect_host == NULL) { 3526 error("No forward host name."); 3527 return 0; 3528 } 3529 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3530 error("Forward host name too long."); 3531 return 0; 3532 } 3533 path = fwd->connect_host; 3534 port = fwd->connect_port; 3535 } 3536 break; 3537 case SSH_CHANNEL_RUNIX_LISTENER: 3538 path = fwd->listen_path; 3539 port = PORT_STREAMLOCAL; 3540 break; 3541 default: 3542 error("%s: unexpected channel type %d", __func__, type); 3543 return 0; 3544 } 3545 3546 if (fwd->listen_path == NULL) { 3547 error("No forward path name."); 3548 return 0; 3549 } 3550 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3551 error("Local listening path too long: %s", fwd->listen_path); 3552 return 0; 3553 } 3554 3555 debug3("%s: type %d path %s", __func__, type, fwd->listen_path); 3556 3557 /* Start a Unix domain listener. */ 3558 omask = umask(fwd_opts->streamlocal_bind_mask); 3559 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3560 fwd_opts->streamlocal_bind_unlink); 3561 umask(omask); 3562 if (sock < 0) 3563 return 0; 3564 3565 debug("Local forwarding listening on path %s.", fwd->listen_path); 3566 3567 /* Allocate a channel number for the socket. */ 3568 c = channel_new(ssh, "unix listener", type, sock, sock, -1, 3569 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3570 0, "unix listener", 1); 3571 c->path = xstrdup(path); 3572 c->host_port = port; 3573 c->listening_port = PORT_STREAMLOCAL; 3574 c->listening_addr = xstrdup(fwd->listen_path); 3575 return 1; 3576 } 3577 3578 static int 3579 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3580 const char *host, u_short port) 3581 { 3582 u_int i; 3583 int found = 0; 3584 3585 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3586 Channel *c = ssh->chanctxt->channels[i]; 3587 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3588 continue; 3589 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3590 debug2("%s: close channel %d", __func__, i); 3591 channel_free(ssh, c); 3592 found = 1; 3593 } 3594 } 3595 3596 return found; 3597 } 3598 3599 static int 3600 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3601 { 3602 u_int i; 3603 int found = 0; 3604 3605 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3606 Channel *c = ssh->chanctxt->channels[i]; 3607 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3608 continue; 3609 if (c->path == NULL) 3610 continue; 3611 if (strcmp(c->path, path) == 0) { 3612 debug2("%s: close channel %d", __func__, i); 3613 channel_free(ssh, c); 3614 found = 1; 3615 } 3616 } 3617 3618 return found; 3619 } 3620 3621 int 3622 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3623 { 3624 if (fwd->listen_path != NULL) { 3625 return channel_cancel_rport_listener_streamlocal(ssh, 3626 fwd->listen_path); 3627 } else { 3628 return channel_cancel_rport_listener_tcpip(ssh, 3629 fwd->listen_host, fwd->listen_port); 3630 } 3631 } 3632 3633 static int 3634 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 3635 const char *lhost, u_short lport, int cport, 3636 struct ForwardOptions *fwd_opts) 3637 { 3638 u_int i; 3639 int found = 0; 3640 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 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_PORT_LISTENER) 3645 continue; 3646 if (c->listening_port != lport) 3647 continue; 3648 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 3649 /* skip dynamic forwardings */ 3650 if (c->host_port == 0) 3651 continue; 3652 } else { 3653 if (c->host_port != cport) 3654 continue; 3655 } 3656 if ((c->listening_addr == NULL && addr != NULL) || 3657 (c->listening_addr != NULL && addr == NULL)) 3658 continue; 3659 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 3660 debug2("%s: close channel %d", __func__, i); 3661 channel_free(ssh, c); 3662 found = 1; 3663 } 3664 } 3665 3666 return found; 3667 } 3668 3669 static int 3670 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 3671 { 3672 u_int i; 3673 int found = 0; 3674 3675 if (path == NULL) { 3676 error("%s: no path specified.", __func__); 3677 return 0; 3678 } 3679 3680 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3681 Channel *c = ssh->chanctxt->channels[i]; 3682 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 3683 continue; 3684 if (c->listening_addr == NULL) 3685 continue; 3686 if (strcmp(c->listening_addr, path) == 0) { 3687 debug2("%s: close channel %d", __func__, i); 3688 channel_free(ssh, c); 3689 found = 1; 3690 } 3691 } 3692 3693 return found; 3694 } 3695 3696 int 3697 channel_cancel_lport_listener(struct ssh *ssh, 3698 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 3699 { 3700 if (fwd->listen_path != NULL) { 3701 return channel_cancel_lport_listener_streamlocal(ssh, 3702 fwd->listen_path); 3703 } else { 3704 return channel_cancel_lport_listener_tcpip(ssh, 3705 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 3706 } 3707 } 3708 3709 /* protocol local port fwd, used by ssh */ 3710 int 3711 channel_setup_local_fwd_listener(struct ssh *ssh, 3712 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3713 { 3714 if (fwd->listen_path != NULL) { 3715 return channel_setup_fwd_listener_streamlocal(ssh, 3716 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 3717 } else { 3718 return channel_setup_fwd_listener_tcpip(ssh, 3719 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 3720 } 3721 } 3722 3723 /* Matches a remote forwarding permission against a requested forwarding */ 3724 static int 3725 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 3726 { 3727 int ret; 3728 char *lhost; 3729 3730 /* XXX add ACLs for streamlocal */ 3731 if (fwd->listen_path != NULL) 3732 return 1; 3733 3734 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 3735 return 0; 3736 3737 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 3738 allowed_open->listen_port != fwd->listen_port) 3739 return 0; 3740 3741 /* Match hostnames case-insensitively */ 3742 lhost = xstrdup(fwd->listen_host); 3743 lowercase(lhost); 3744 ret = match_pattern(lhost, allowed_open->listen_host); 3745 free(lhost); 3746 3747 return ret; 3748 } 3749 3750 /* Checks whether a requested remote forwarding is permitted */ 3751 static int 3752 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 3753 { 3754 struct ssh_channels *sc = ssh->chanctxt; 3755 struct permission_set *pset = &sc->remote_perms; 3756 u_int i, permit, permit_adm = 1; 3757 struct permission *perm; 3758 3759 /* XXX apply GatewayPorts override before checking? */ 3760 3761 permit = pset->all_permitted; 3762 if (!permit) { 3763 for (i = 0; i < pset->num_permitted_user; i++) { 3764 perm = &pset->permitted_user[i]; 3765 if (remote_open_match(perm, fwd)) { 3766 permit = 1; 3767 break; 3768 } 3769 } 3770 } 3771 3772 if (pset->num_permitted_admin > 0) { 3773 permit_adm = 0; 3774 for (i = 0; i < pset->num_permitted_admin; i++) { 3775 perm = &pset->permitted_admin[i]; 3776 if (remote_open_match(perm, fwd)) { 3777 permit_adm = 1; 3778 break; 3779 } 3780 } 3781 } 3782 3783 return permit && permit_adm; 3784 } 3785 3786 /* protocol v2 remote port fwd, used by sshd */ 3787 int 3788 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 3789 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 3790 { 3791 if (!check_rfwd_permission(ssh, fwd)) { 3792 ssh_packet_send_debug(ssh, "port forwarding refused"); 3793 if (fwd->listen_path != NULL) 3794 /* XXX always allowed, see remote_open_match() */ 3795 logit("Received request from %.100s port %d to " 3796 "remote forward to path \"%.100s\", " 3797 "but the request was denied.", 3798 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 3799 fwd->listen_path); 3800 else if(fwd->listen_host != NULL) 3801 logit("Received request from %.100s port %d to " 3802 "remote forward to host %.100s port %d, " 3803 "but the request was denied.", 3804 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 3805 fwd->listen_host, fwd->listen_port ); 3806 else 3807 logit("Received request from %.100s port %d to remote " 3808 "forward, but the request was denied.", 3809 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 3810 return 0; 3811 } 3812 if (fwd->listen_path != NULL) { 3813 return channel_setup_fwd_listener_streamlocal(ssh, 3814 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 3815 } else { 3816 return channel_setup_fwd_listener_tcpip(ssh, 3817 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 3818 fwd_opts); 3819 } 3820 } 3821 3822 /* 3823 * Translate the requested rfwd listen host to something usable for 3824 * this server. 3825 */ 3826 static const char * 3827 channel_rfwd_bind_host(const char *listen_host) 3828 { 3829 if (listen_host == NULL) { 3830 return "localhost"; 3831 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 3832 return ""; 3833 } else 3834 return listen_host; 3835 } 3836 3837 /* 3838 * Initiate forwarding of connections to port "port" on remote host through 3839 * the secure channel to host:port from local side. 3840 * Returns handle (index) for updating the dynamic listen port with 3841 * channel_update_permission(). 3842 */ 3843 int 3844 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 3845 { 3846 int r, success = 0, idx = -1; 3847 char *host_to_connect, *listen_host, *listen_path; 3848 int port_to_connect, listen_port; 3849 3850 /* Send the forward request to the remote side. */ 3851 if (fwd->listen_path != NULL) { 3852 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3853 (r = sshpkt_put_cstring(ssh, 3854 "streamlocal-forward@openssh.com")) != 0 || 3855 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 3856 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 3857 (r = sshpkt_send(ssh)) != 0 || 3858 (r = ssh_packet_write_wait(ssh)) != 0) 3859 fatal("%s: request streamlocal: %s", 3860 __func__, ssh_err(r)); 3861 } else { 3862 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3863 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 3864 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 3865 (r = sshpkt_put_cstring(ssh, 3866 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 3867 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 3868 (r = sshpkt_send(ssh)) != 0 || 3869 (r = ssh_packet_write_wait(ssh)) != 0) 3870 fatal("%s: request tcpip-forward: %s", 3871 __func__, ssh_err(r)); 3872 } 3873 /* Assume that server accepts the request */ 3874 success = 1; 3875 if (success) { 3876 /* Record that connection to this host/port is permitted. */ 3877 host_to_connect = listen_host = listen_path = NULL; 3878 port_to_connect = listen_port = 0; 3879 if (fwd->connect_path != NULL) { 3880 host_to_connect = xstrdup(fwd->connect_path); 3881 port_to_connect = PORT_STREAMLOCAL; 3882 } else { 3883 host_to_connect = xstrdup(fwd->connect_host); 3884 port_to_connect = fwd->connect_port; 3885 } 3886 if (fwd->listen_path != NULL) { 3887 listen_path = xstrdup(fwd->listen_path); 3888 listen_port = PORT_STREAMLOCAL; 3889 } else { 3890 if (fwd->listen_host != NULL) 3891 listen_host = xstrdup(fwd->listen_host); 3892 listen_port = fwd->listen_port; 3893 } 3894 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 3895 host_to_connect, port_to_connect, 3896 listen_host, listen_path, listen_port, NULL); 3897 } 3898 return idx; 3899 } 3900 3901 static int 3902 open_match(struct permission *allowed_open, const char *requestedhost, 3903 int requestedport) 3904 { 3905 if (allowed_open->host_to_connect == NULL) 3906 return 0; 3907 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 3908 allowed_open->port_to_connect != requestedport) 3909 return 0; 3910 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 3911 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 3912 return 0; 3913 return 1; 3914 } 3915 3916 /* 3917 * Note that in the listen host/port case 3918 * we don't support FWD_PERMIT_ANY_PORT and 3919 * need to translate between the configured-host (listen_host) 3920 * and what we've sent to the remote server (channel_rfwd_bind_host) 3921 */ 3922 static int 3923 open_listen_match_tcpip(struct permission *allowed_open, 3924 const char *requestedhost, u_short requestedport, int translate) 3925 { 3926 const char *allowed_host; 3927 3928 if (allowed_open->host_to_connect == NULL) 3929 return 0; 3930 if (allowed_open->listen_port != requestedport) 3931 return 0; 3932 if (!translate && allowed_open->listen_host == NULL && 3933 requestedhost == NULL) 3934 return 1; 3935 allowed_host = translate ? 3936 channel_rfwd_bind_host(allowed_open->listen_host) : 3937 allowed_open->listen_host; 3938 if (allowed_host == NULL || requestedhost == NULL || 3939 strcmp(allowed_host, requestedhost) != 0) 3940 return 0; 3941 return 1; 3942 } 3943 3944 static int 3945 open_listen_match_streamlocal(struct permission *allowed_open, 3946 const char *requestedpath) 3947 { 3948 if (allowed_open->host_to_connect == NULL) 3949 return 0; 3950 if (allowed_open->listen_port != PORT_STREAMLOCAL) 3951 return 0; 3952 if (allowed_open->listen_path == NULL || 3953 strcmp(allowed_open->listen_path, requestedpath) != 0) 3954 return 0; 3955 return 1; 3956 } 3957 3958 /* 3959 * Request cancellation of remote forwarding of connection host:port from 3960 * local side. 3961 */ 3962 static int 3963 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 3964 const char *host, u_short port) 3965 { 3966 struct ssh_channels *sc = ssh->chanctxt; 3967 struct permission_set *pset = &sc->local_perms; 3968 int r; 3969 u_int i; 3970 struct permission *perm = NULL; 3971 3972 for (i = 0; i < pset->num_permitted_user; i++) { 3973 perm = &pset->permitted_user[i]; 3974 if (open_listen_match_tcpip(perm, host, port, 0)) 3975 break; 3976 perm = NULL; 3977 } 3978 if (perm == NULL) { 3979 debug("%s: requested forward not found", __func__); 3980 return -1; 3981 } 3982 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3983 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 3984 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 3985 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 3986 (r = sshpkt_put_u32(ssh, port)) != 0 || 3987 (r = sshpkt_send(ssh)) != 0) 3988 fatal("%s: send cancel: %s", __func__, ssh_err(r)); 3989 3990 fwd_perm_clear(perm); /* unregister */ 3991 3992 return 0; 3993 } 3994 3995 /* 3996 * Request cancellation of remote forwarding of Unix domain socket 3997 * path from local side. 3998 */ 3999 static int 4000 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4001 { 4002 struct ssh_channels *sc = ssh->chanctxt; 4003 struct permission_set *pset = &sc->local_perms; 4004 int r; 4005 u_int i; 4006 struct permission *perm = NULL; 4007 4008 for (i = 0; i < pset->num_permitted_user; i++) { 4009 perm = &pset->permitted_user[i]; 4010 if (open_listen_match_streamlocal(perm, path)) 4011 break; 4012 perm = NULL; 4013 } 4014 if (perm == NULL) { 4015 debug("%s: requested forward not found", __func__); 4016 return -1; 4017 } 4018 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4019 (r = sshpkt_put_cstring(ssh, 4020 "cancel-streamlocal-forward@openssh.com")) != 0 || 4021 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4022 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4023 (r = sshpkt_send(ssh)) != 0) 4024 fatal("%s: send cancel: %s", __func__, ssh_err(r)); 4025 4026 fwd_perm_clear(perm); /* unregister */ 4027 4028 return 0; 4029 } 4030 4031 /* 4032 * Request cancellation of remote forwarding of a connection from local side. 4033 */ 4034 int 4035 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4036 { 4037 if (fwd->listen_path != NULL) { 4038 return channel_request_rforward_cancel_streamlocal(ssh, 4039 fwd->listen_path); 4040 } else { 4041 return channel_request_rforward_cancel_tcpip(ssh, 4042 fwd->listen_host, 4043 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4044 } 4045 } 4046 4047 /* 4048 * Permits opening to any host/port if permitted_user[] is empty. This is 4049 * usually called by the server, because the user could connect to any port 4050 * anyway, and the server has no way to know but to trust the client anyway. 4051 */ 4052 void 4053 channel_permit_all(struct ssh *ssh, int where) 4054 { 4055 struct permission_set *pset = permission_set_get(ssh, where); 4056 4057 if (pset->num_permitted_user == 0) 4058 pset->all_permitted = 1; 4059 } 4060 4061 /* 4062 * Permit the specified host/port for forwarding. 4063 */ 4064 void 4065 channel_add_permission(struct ssh *ssh, int who, int where, 4066 char *host, int port) 4067 { 4068 int local = where == FORWARD_LOCAL; 4069 struct permission_set *pset = permission_set_get(ssh, where); 4070 4071 debug("allow %s forwarding to host %s port %d", 4072 fwd_ident(who, where), host, port); 4073 /* 4074 * Remote forwards set listen_host/port, local forwards set 4075 * host/port_to_connect. 4076 */ 4077 permission_set_add(ssh, who, where, 4078 local ? host : 0, local ? port : 0, 4079 local ? NULL : host, NULL, local ? 0 : port, NULL); 4080 pset->all_permitted = 0; 4081 } 4082 4083 /* 4084 * Administratively disable forwarding. 4085 */ 4086 void 4087 channel_disable_admin(struct ssh *ssh, int where) 4088 { 4089 channel_clear_permission(ssh, FORWARD_ADM, where); 4090 permission_set_add(ssh, FORWARD_ADM, where, 4091 NULL, 0, NULL, NULL, 0, NULL); 4092 } 4093 4094 /* 4095 * Clear a list of permitted opens. 4096 */ 4097 void 4098 channel_clear_permission(struct ssh *ssh, int who, int where) 4099 { 4100 struct permission **permp; 4101 u_int *npermp; 4102 4103 permission_set_get_array(ssh, who, where, &permp, &npermp); 4104 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4105 *npermp = 0; 4106 } 4107 4108 /* 4109 * Update the listen port for a dynamic remote forward, after 4110 * the actual 'newport' has been allocated. If 'newport' < 0 is 4111 * passed then they entry will be invalidated. 4112 */ 4113 void 4114 channel_update_permission(struct ssh *ssh, int idx, int newport) 4115 { 4116 struct permission_set *pset = &ssh->chanctxt->local_perms; 4117 4118 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4119 debug("%s: index out of range: %d num_permitted_user %d", 4120 __func__, idx, pset->num_permitted_user); 4121 return; 4122 } 4123 debug("%s allowed port %d for forwarding to host %s port %d", 4124 newport > 0 ? "Updating" : "Removing", 4125 newport, 4126 pset->permitted_user[idx].host_to_connect, 4127 pset->permitted_user[idx].port_to_connect); 4128 if (newport <= 0) 4129 fwd_perm_clear(&pset->permitted_user[idx]); 4130 else { 4131 pset->permitted_user[idx].listen_port = 4132 (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4133 } 4134 } 4135 4136 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4137 int 4138 permitopen_port(const char *p) 4139 { 4140 int port; 4141 4142 if (strcmp(p, "*") == 0) 4143 return FWD_PERMIT_ANY_PORT; 4144 if ((port = a2port(p)) > 0) 4145 return port; 4146 return -1; 4147 } 4148 4149 /* Try to start non-blocking connect to next host in cctx list */ 4150 static int 4151 connect_next(struct channel_connect *cctx) 4152 { 4153 int sock, saved_errno; 4154 struct sockaddr_un *sunaddr; 4155 char ntop[NI_MAXHOST]; 4156 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4157 4158 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4159 switch (cctx->ai->ai_family) { 4160 case AF_UNIX: 4161 /* unix:pathname instead of host:port */ 4162 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4163 strlcpy(ntop, "unix", sizeof(ntop)); 4164 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4165 break; 4166 case AF_INET: 4167 case AF_INET6: 4168 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4169 ntop, sizeof(ntop), strport, sizeof(strport), 4170 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4171 error("connect_next: getnameinfo failed"); 4172 continue; 4173 } 4174 break; 4175 default: 4176 continue; 4177 } 4178 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4179 cctx->ai->ai_protocol)) == -1) { 4180 if (cctx->ai->ai_next == NULL) 4181 error("socket: %.100s", strerror(errno)); 4182 else 4183 verbose("socket: %.100s", strerror(errno)); 4184 continue; 4185 } 4186 if (set_nonblock(sock) == -1) 4187 fatal("%s: set_nonblock(%d)", __func__, sock); 4188 if (connect(sock, cctx->ai->ai_addr, 4189 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4190 debug("connect_next: host %.100s ([%.100s]:%s): " 4191 "%.100s", cctx->host, ntop, strport, 4192 strerror(errno)); 4193 saved_errno = errno; 4194 close(sock); 4195 errno = saved_errno; 4196 continue; /* fail -- try next */ 4197 } 4198 if (cctx->ai->ai_family != AF_UNIX) 4199 set_nodelay(sock); 4200 debug("connect_next: host %.100s ([%.100s]:%s) " 4201 "in progress, fd=%d", cctx->host, ntop, strport, sock); 4202 cctx->ai = cctx->ai->ai_next; 4203 return sock; 4204 } 4205 return -1; 4206 } 4207 4208 static void 4209 channel_connect_ctx_free(struct channel_connect *cctx) 4210 { 4211 free(cctx->host); 4212 if (cctx->aitop) { 4213 if (cctx->aitop->ai_family == AF_UNIX) 4214 free(cctx->aitop); 4215 else 4216 freeaddrinfo(cctx->aitop); 4217 } 4218 memset(cctx, 0, sizeof(*cctx)); 4219 } 4220 4221 /* 4222 * Return connecting socket to remote host:port or local socket path, 4223 * passing back the failure reason if appropriate. 4224 */ 4225 static int 4226 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4227 char *ctype, char *rname, struct channel_connect *cctx, 4228 int *reason, const char **errmsg) 4229 { 4230 struct addrinfo hints; 4231 int gaierr; 4232 int sock = -1; 4233 char strport[NI_MAXSERV]; 4234 4235 if (port == PORT_STREAMLOCAL) { 4236 struct sockaddr_un *sunaddr; 4237 struct addrinfo *ai; 4238 4239 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4240 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4241 return -1; 4242 } 4243 4244 /* 4245 * Fake up a struct addrinfo for AF_UNIX connections. 4246 * channel_connect_ctx_free() must check ai_family 4247 * and use free() not freeaddirinfo() for AF_UNIX. 4248 */ 4249 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4250 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4251 ai->ai_addr = (struct sockaddr *)(ai + 1); 4252 ai->ai_addrlen = sizeof(*sunaddr); 4253 ai->ai_family = AF_UNIX; 4254 ai->ai_socktype = socktype; 4255 ai->ai_protocol = PF_UNSPEC; 4256 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4257 sunaddr->sun_family = AF_UNIX; 4258 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4259 cctx->aitop = ai; 4260 } else { 4261 memset(&hints, 0, sizeof(hints)); 4262 hints.ai_family = ssh->chanctxt->IPv4or6; 4263 hints.ai_socktype = socktype; 4264 snprintf(strport, sizeof strport, "%d", port); 4265 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4266 != 0) { 4267 if (errmsg != NULL) 4268 *errmsg = ssh_gai_strerror(gaierr); 4269 if (reason != NULL) 4270 *reason = SSH2_OPEN_CONNECT_FAILED; 4271 error("connect_to %.100s: unknown host (%s)", name, 4272 ssh_gai_strerror(gaierr)); 4273 return -1; 4274 } 4275 } 4276 4277 cctx->host = xstrdup(name); 4278 cctx->port = port; 4279 cctx->ai = cctx->aitop; 4280 4281 if ((sock = connect_next(cctx)) == -1) { 4282 error("connect to %.100s port %d failed: %s", 4283 name, port, strerror(errno)); 4284 return -1; 4285 } 4286 4287 return sock; 4288 } 4289 4290 /* Return CONNECTING channel to remote host:port or local socket path */ 4291 static Channel * 4292 connect_to(struct ssh *ssh, const char *host, int port, 4293 char *ctype, char *rname) 4294 { 4295 struct channel_connect cctx; 4296 Channel *c; 4297 int sock; 4298 4299 memset(&cctx, 0, sizeof(cctx)); 4300 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4301 &cctx, NULL, NULL); 4302 if (sock == -1) { 4303 channel_connect_ctx_free(&cctx); 4304 return NULL; 4305 } 4306 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4307 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4308 c->host_port = port; 4309 c->path = xstrdup(host); 4310 c->connect_ctx = cctx; 4311 4312 return c; 4313 } 4314 4315 /* 4316 * returns either the newly connected channel or the downstream channel 4317 * that needs to deal with this connection. 4318 */ 4319 Channel * 4320 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4321 u_short listen_port, char *ctype, char *rname) 4322 { 4323 struct ssh_channels *sc = ssh->chanctxt; 4324 struct permission_set *pset = &sc->local_perms; 4325 u_int i; 4326 struct permission *perm; 4327 4328 for (i = 0; i < pset->num_permitted_user; i++) { 4329 perm = &pset->permitted_user[i]; 4330 if (open_listen_match_tcpip(perm, 4331 listen_host, listen_port, 1)) { 4332 if (perm->downstream) 4333 return perm->downstream; 4334 if (perm->port_to_connect == 0) 4335 return rdynamic_connect_prepare(ssh, 4336 ctype, rname); 4337 return connect_to(ssh, 4338 perm->host_to_connect, perm->port_to_connect, 4339 ctype, rname); 4340 } 4341 } 4342 error("WARNING: Server requests forwarding for unknown listen_port %d", 4343 listen_port); 4344 return NULL; 4345 } 4346 4347 Channel * 4348 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4349 char *ctype, char *rname) 4350 { 4351 struct ssh_channels *sc = ssh->chanctxt; 4352 struct permission_set *pset = &sc->local_perms; 4353 u_int i; 4354 struct permission *perm; 4355 4356 for (i = 0; i < pset->num_permitted_user; i++) { 4357 perm = &pset->permitted_user[i]; 4358 if (open_listen_match_streamlocal(perm, path)) { 4359 return connect_to(ssh, 4360 perm->host_to_connect, perm->port_to_connect, 4361 ctype, rname); 4362 } 4363 } 4364 error("WARNING: Server requests forwarding for unknown path %.100s", 4365 path); 4366 return NULL; 4367 } 4368 4369 /* Check if connecting to that port is permitted and connect. */ 4370 Channel * 4371 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4372 char *ctype, char *rname, int *reason, const char **errmsg) 4373 { 4374 struct ssh_channels *sc = ssh->chanctxt; 4375 struct permission_set *pset = &sc->local_perms; 4376 struct channel_connect cctx; 4377 Channel *c; 4378 u_int i, permit, permit_adm = 1; 4379 int sock; 4380 struct permission *perm; 4381 4382 permit = pset->all_permitted; 4383 if (!permit) { 4384 for (i = 0; i < pset->num_permitted_user; i++) { 4385 perm = &pset->permitted_user[i]; 4386 if (open_match(perm, host, port)) { 4387 permit = 1; 4388 break; 4389 } 4390 } 4391 } 4392 4393 if (pset->num_permitted_admin > 0) { 4394 permit_adm = 0; 4395 for (i = 0; i < pset->num_permitted_admin; i++) { 4396 perm = &pset->permitted_admin[i]; 4397 if (open_match(perm, host, port)) { 4398 permit_adm = 1; 4399 break; 4400 } 4401 } 4402 } 4403 4404 if (!permit || !permit_adm) { 4405 logit("Received request from %.100s port %d to connect to " 4406 "host %.100s port %d, but the request was denied.", 4407 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4408 if (reason != NULL) 4409 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4410 return NULL; 4411 } 4412 4413 memset(&cctx, 0, sizeof(cctx)); 4414 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4415 &cctx, reason, errmsg); 4416 if (sock == -1) { 4417 channel_connect_ctx_free(&cctx); 4418 return NULL; 4419 } 4420 4421 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4422 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4423 c->host_port = port; 4424 c->path = xstrdup(host); 4425 c->connect_ctx = cctx; 4426 4427 return c; 4428 } 4429 4430 /* Check if connecting to that path is permitted and connect. */ 4431 Channel * 4432 channel_connect_to_path(struct ssh *ssh, const char *path, 4433 char *ctype, char *rname) 4434 { 4435 struct ssh_channels *sc = ssh->chanctxt; 4436 struct permission_set *pset = &sc->local_perms; 4437 u_int i, permit, permit_adm = 1; 4438 struct permission *perm; 4439 4440 permit = pset->all_permitted; 4441 if (!permit) { 4442 for (i = 0; i < pset->num_permitted_user; i++) { 4443 perm = &pset->permitted_user[i]; 4444 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4445 permit = 1; 4446 break; 4447 } 4448 } 4449 } 4450 4451 if (pset->num_permitted_admin > 0) { 4452 permit_adm = 0; 4453 for (i = 0; i < pset->num_permitted_admin; i++) { 4454 perm = &pset->permitted_admin[i]; 4455 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4456 permit_adm = 1; 4457 break; 4458 } 4459 } 4460 } 4461 4462 if (!permit || !permit_adm) { 4463 logit("Received request to connect to path %.100s, " 4464 "but the request was denied.", path); 4465 return NULL; 4466 } 4467 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4468 } 4469 4470 void 4471 channel_send_window_changes(struct ssh *ssh) 4472 { 4473 struct ssh_channels *sc = ssh->chanctxt; 4474 struct winsize ws; 4475 int r; 4476 u_int i; 4477 4478 for (i = 0; i < sc->channels_alloc; i++) { 4479 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4480 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4481 continue; 4482 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4483 continue; 4484 channel_request_start(ssh, i, "window-change", 0); 4485 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4486 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4487 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4488 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4489 (r = sshpkt_send(ssh)) != 0) 4490 fatal("%s: channel %u: send window-change: %s", 4491 __func__, i, ssh_err(r)); 4492 } 4493 } 4494 4495 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4496 static Channel * 4497 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4498 { 4499 Channel *c; 4500 int r; 4501 4502 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4503 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4504 c->host_port = 0; 4505 c->path = NULL; 4506 4507 /* 4508 * We need to open the channel before we have a FD, 4509 * so that we can get SOCKS header from peer. 4510 */ 4511 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4512 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4513 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4514 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4515 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 4516 fatal("%s: channel %i: confirm: %s", __func__, 4517 c->self, ssh_err(r)); 4518 } 4519 return c; 4520 } 4521 4522 /* Return CONNECTING socket to remote host:port or local socket path */ 4523 static int 4524 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4525 { 4526 struct channel_connect cctx; 4527 int sock; 4528 4529 memset(&cctx, 0, sizeof(cctx)); 4530 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4531 NULL, &cctx, NULL, NULL); 4532 if (sock == -1) 4533 channel_connect_ctx_free(&cctx); 4534 else { 4535 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4536 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4537 c->connect_ctx = cctx; 4538 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4539 } 4540 return sock; 4541 } 4542 4543 /* -- X11 forwarding */ 4544 4545 /* 4546 * Creates an internet domain socket for listening for X11 connections. 4547 * Returns 0 and a suitable display number for the DISPLAY variable 4548 * stored in display_numberp , or -1 if an error occurs. 4549 */ 4550 int 4551 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4552 int x11_use_localhost, int single_connection, 4553 u_int *display_numberp, int **chanids) 4554 { 4555 Channel *nc = NULL; 4556 int display_number, sock; 4557 u_short port; 4558 struct addrinfo hints, *ai, *aitop; 4559 char strport[NI_MAXSERV]; 4560 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4561 4562 if (chanids == NULL) 4563 return -1; 4564 4565 for (display_number = x11_display_offset; 4566 display_number < MAX_DISPLAYS; 4567 display_number++) { 4568 port = 6000 + display_number; 4569 memset(&hints, 0, sizeof(hints)); 4570 hints.ai_family = ssh->chanctxt->IPv4or6; 4571 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4572 hints.ai_socktype = SOCK_STREAM; 4573 snprintf(strport, sizeof strport, "%d", port); 4574 if ((gaierr = getaddrinfo(NULL, strport, 4575 &hints, &aitop)) != 0) { 4576 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4577 return -1; 4578 } 4579 for (ai = aitop; ai; ai = ai->ai_next) { 4580 if (ai->ai_family != AF_INET && 4581 ai->ai_family != AF_INET6) 4582 continue; 4583 sock = socket(ai->ai_family, ai->ai_socktype, 4584 ai->ai_protocol); 4585 if (sock == -1) { 4586 error("socket: %.100s", strerror(errno)); 4587 freeaddrinfo(aitop); 4588 return -1; 4589 } 4590 set_reuseaddr(sock); 4591 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4592 debug2("%s: bind port %d: %.100s", __func__, 4593 port, strerror(errno)); 4594 close(sock); 4595 for (n = 0; n < num_socks; n++) 4596 close(socks[n]); 4597 num_socks = 0; 4598 break; 4599 } 4600 socks[num_socks++] = sock; 4601 if (num_socks == NUM_SOCKS) 4602 break; 4603 } 4604 freeaddrinfo(aitop); 4605 if (num_socks > 0) 4606 break; 4607 } 4608 if (display_number >= MAX_DISPLAYS) { 4609 error("Failed to allocate internet-domain X11 display socket."); 4610 return -1; 4611 } 4612 /* Start listening for connections on the socket. */ 4613 for (n = 0; n < num_socks; n++) { 4614 sock = socks[n]; 4615 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 4616 error("listen: %.100s", strerror(errno)); 4617 close(sock); 4618 return -1; 4619 } 4620 } 4621 4622 /* Allocate a channel for each socket. */ 4623 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 4624 for (n = 0; n < num_socks; n++) { 4625 sock = socks[n]; 4626 nc = channel_new(ssh, "x11 listener", 4627 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4628 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 4629 0, "X11 inet listener", 1); 4630 nc->single_connection = single_connection; 4631 (*chanids)[n] = nc->self; 4632 } 4633 (*chanids)[n] = -1; 4634 4635 /* Return the display number for the DISPLAY environment variable. */ 4636 *display_numberp = display_number; 4637 return 0; 4638 } 4639 4640 static int 4641 connect_local_xsocket(u_int dnr) 4642 { 4643 int sock; 4644 struct sockaddr_un addr; 4645 4646 sock = socket(AF_UNIX, SOCK_STREAM, 0); 4647 if (sock == -1) 4648 error("socket: %.100s", strerror(errno)); 4649 memset(&addr, 0, sizeof(addr)); 4650 addr.sun_family = AF_UNIX; 4651 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 4652 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 4653 return sock; 4654 close(sock); 4655 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 4656 return -1; 4657 } 4658 4659 int 4660 x11_connect_display(struct ssh *ssh) 4661 { 4662 u_int display_number; 4663 const char *display; 4664 char buf[1024], *cp; 4665 struct addrinfo hints, *ai, *aitop; 4666 char strport[NI_MAXSERV]; 4667 int gaierr, sock = 0; 4668 4669 /* Try to open a socket for the local X server. */ 4670 display = getenv("DISPLAY"); 4671 if (!display) { 4672 error("DISPLAY not set."); 4673 return -1; 4674 } 4675 /* 4676 * Now we decode the value of the DISPLAY variable and make a 4677 * connection to the real X server. 4678 */ 4679 4680 /* 4681 * Check if it is a unix domain socket. Unix domain displays are in 4682 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 4683 */ 4684 if (strncmp(display, "unix:", 5) == 0 || 4685 display[0] == ':') { 4686 /* Connect to the unix domain socket. */ 4687 if (sscanf(strrchr(display, ':') + 1, "%u", 4688 &display_number) != 1) { 4689 error("Could not parse display number from DISPLAY: " 4690 "%.100s", display); 4691 return -1; 4692 } 4693 /* Create a socket. */ 4694 sock = connect_local_xsocket(display_number); 4695 if (sock < 0) 4696 return -1; 4697 4698 /* OK, we now have a connection to the display. */ 4699 return sock; 4700 } 4701 /* 4702 * Connect to an inet socket. The DISPLAY value is supposedly 4703 * hostname:d[.s], where hostname may also be numeric IP address. 4704 */ 4705 strlcpy(buf, display, sizeof(buf)); 4706 cp = strchr(buf, ':'); 4707 if (!cp) { 4708 error("Could not find ':' in DISPLAY: %.100s", display); 4709 return -1; 4710 } 4711 *cp = 0; 4712 /* 4713 * buf now contains the host name. But first we parse the 4714 * display number. 4715 */ 4716 if (sscanf(cp + 1, "%u", &display_number) != 1) { 4717 error("Could not parse display number from DISPLAY: %.100s", 4718 display); 4719 return -1; 4720 } 4721 4722 /* Look up the host address */ 4723 memset(&hints, 0, sizeof(hints)); 4724 hints.ai_family = ssh->chanctxt->IPv4or6; 4725 hints.ai_socktype = SOCK_STREAM; 4726 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 4727 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 4728 error("%.100s: unknown host. (%s)", buf, 4729 ssh_gai_strerror(gaierr)); 4730 return -1; 4731 } 4732 for (ai = aitop; ai; ai = ai->ai_next) { 4733 /* Create a socket. */ 4734 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 4735 if (sock == -1) { 4736 debug2("socket: %.100s", strerror(errno)); 4737 continue; 4738 } 4739 /* Connect it to the display. */ 4740 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4741 debug2("connect %.100s port %u: %.100s", buf, 4742 6000 + display_number, strerror(errno)); 4743 close(sock); 4744 continue; 4745 } 4746 /* Success */ 4747 break; 4748 } 4749 freeaddrinfo(aitop); 4750 if (!ai) { 4751 error("connect %.100s port %u: %.100s", buf, 4752 6000 + display_number, strerror(errno)); 4753 return -1; 4754 } 4755 set_nodelay(sock); 4756 return sock; 4757 } 4758 4759 /* 4760 * Requests forwarding of X11 connections, generates fake authentication 4761 * data, and enables authentication spoofing. 4762 * This should be called in the client only. 4763 */ 4764 void 4765 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 4766 const char *disp, const char *proto, const char *data, int want_reply) 4767 { 4768 struct ssh_channels *sc = ssh->chanctxt; 4769 u_int data_len = (u_int) strlen(data) / 2; 4770 u_int i, value; 4771 const char *cp; 4772 char *new_data; 4773 int r, screen_number; 4774 4775 if (sc->x11_saved_display == NULL) 4776 sc->x11_saved_display = xstrdup(disp); 4777 else if (strcmp(disp, sc->x11_saved_display) != 0) { 4778 error("x11_request_forwarding_with_spoofing: different " 4779 "$DISPLAY already forwarded"); 4780 return; 4781 } 4782 4783 cp = strchr(disp, ':'); 4784 if (cp) 4785 cp = strchr(cp, '.'); 4786 if (cp) 4787 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 4788 else 4789 screen_number = 0; 4790 4791 if (sc->x11_saved_proto == NULL) { 4792 /* Save protocol name. */ 4793 sc->x11_saved_proto = xstrdup(proto); 4794 4795 /* Extract real authentication data. */ 4796 sc->x11_saved_data = xmalloc(data_len); 4797 for (i = 0; i < data_len; i++) { 4798 if (sscanf(data + 2 * i, "%2x", &value) != 1) 4799 fatal("x11_request_forwarding: bad " 4800 "authentication data: %.100s", data); 4801 sc->x11_saved_data[i] = value; 4802 } 4803 sc->x11_saved_data_len = data_len; 4804 4805 /* Generate fake data of the same length. */ 4806 sc->x11_fake_data = xmalloc(data_len); 4807 arc4random_buf(sc->x11_fake_data, data_len); 4808 sc->x11_fake_data_len = data_len; 4809 } 4810 4811 /* Convert the fake data into hex. */ 4812 new_data = tohex(sc->x11_fake_data, data_len); 4813 4814 /* Send the request packet. */ 4815 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 4816 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 4817 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 4818 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 4819 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 4820 (r = sshpkt_send(ssh)) != 0 || 4821 (r = ssh_packet_write_wait(ssh)) != 0) 4822 fatal("%s: send x11-req: %s", __func__, ssh_err(r)); 4823 free(new_data); 4824 } 4825