1 /* $OpenBSD: channels.c,v 1.387 2018/12/07 02:31:20 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include <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; 347 348 /* Try to find a free slot where to put the new channel. */ 349 for (i = 0; i < sc->channels_alloc; i++) { 350 if (sc->channels[i] == NULL) { 351 /* Found a free slot. */ 352 found = i; 353 break; 354 } 355 } 356 if (i >= sc->channels_alloc) { 357 /* 358 * There are no free slots. Take last+1 slot and expand 359 * the array. 360 */ 361 found = sc->channels_alloc; 362 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 363 fatal("%s: internal error: channels_alloc %d too big", 364 __func__, sc->channels_alloc); 365 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 366 sc->channels_alloc + 10, sizeof(*sc->channels)); 367 sc->channels_alloc += 10; 368 debug2("channel: expanding %d", sc->channels_alloc); 369 } 370 /* Initialize and return new channel. */ 371 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 372 if ((c->input = sshbuf_new()) == NULL || 373 (c->output = sshbuf_new()) == NULL || 374 (c->extended = sshbuf_new()) == NULL) 375 fatal("%s: sshbuf_new failed", __func__); 376 c->ostate = CHAN_OUTPUT_OPEN; 377 c->istate = CHAN_INPUT_OPEN; 378 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 379 c->self = found; 380 c->type = type; 381 c->ctype = ctype; 382 c->local_window = window; 383 c->local_window_max = window; 384 c->local_maxpacket = maxpack; 385 c->remote_name = xstrdup(remote_name); 386 c->ctl_chan = -1; 387 c->delayed = 1; /* prevent call to channel_post handler */ 388 TAILQ_INIT(&c->status_confirms); 389 debug("channel %d: new [%s]", found, remote_name); 390 return c; 391 } 392 393 static void 394 channel_find_maxfd(struct ssh_channels *sc) 395 { 396 u_int i; 397 int max = 0; 398 Channel *c; 399 400 for (i = 0; i < sc->channels_alloc; i++) { 401 c = sc->channels[i]; 402 if (c != NULL) { 403 max = MAXIMUM(max, c->rfd); 404 max = MAXIMUM(max, c->wfd); 405 max = MAXIMUM(max, c->efd); 406 } 407 } 408 sc->channel_max_fd = max; 409 } 410 411 int 412 channel_close_fd(struct ssh *ssh, int *fdp) 413 { 414 struct ssh_channels *sc = ssh->chanctxt; 415 int ret = 0, fd = *fdp; 416 417 if (fd != -1) { 418 ret = close(fd); 419 *fdp = -1; 420 if (fd == sc->channel_max_fd) 421 channel_find_maxfd(sc); 422 } 423 return ret; 424 } 425 426 /* Close all channel fd/socket. */ 427 static void 428 channel_close_fds(struct ssh *ssh, Channel *c) 429 { 430 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 431 432 channel_close_fd(ssh, &c->sock); 433 if (rfd != sock) 434 channel_close_fd(ssh, &c->rfd); 435 if (wfd != sock && wfd != rfd) 436 channel_close_fd(ssh, &c->wfd); 437 if (efd != sock && efd != rfd && efd != wfd) 438 channel_close_fd(ssh, &c->efd); 439 } 440 441 static void 442 fwd_perm_clear(struct permission *perm) 443 { 444 free(perm->host_to_connect); 445 free(perm->listen_host); 446 free(perm->listen_path); 447 bzero(perm, sizeof(*perm)); 448 } 449 450 /* Returns an printable name for the specified forwarding permission list */ 451 static const char * 452 fwd_ident(int who, int where) 453 { 454 if (who == FORWARD_ADM) { 455 if (where == FORWARD_LOCAL) 456 return "admin local"; 457 else if (where == FORWARD_REMOTE) 458 return "admin remote"; 459 } else if (who == FORWARD_USER) { 460 if (where == FORWARD_LOCAL) 461 return "user local"; 462 else if (where == FORWARD_REMOTE) 463 return "user remote"; 464 } 465 fatal("Unknown forward permission list %d/%d", who, where); 466 } 467 468 /* Returns the forwarding permission list for the specified direction */ 469 static struct permission_set * 470 permission_set_get(struct ssh *ssh, int where) 471 { 472 struct ssh_channels *sc = ssh->chanctxt; 473 474 switch (where) { 475 case FORWARD_LOCAL: 476 return &sc->local_perms; 477 break; 478 case FORWARD_REMOTE: 479 return &sc->remote_perms; 480 break; 481 default: 482 fatal("%s: invalid forwarding direction %d", __func__, where); 483 } 484 } 485 486 /* Reutrns pointers to the specified forwarding list and its element count */ 487 static void 488 permission_set_get_array(struct ssh *ssh, int who, int where, 489 struct permission ***permpp, u_int **npermpp) 490 { 491 struct permission_set *pset = permission_set_get(ssh, where); 492 493 switch (who) { 494 case FORWARD_USER: 495 *permpp = &pset->permitted_user; 496 *npermpp = &pset->num_permitted_user; 497 break; 498 case FORWARD_ADM: 499 *permpp = &pset->permitted_admin; 500 *npermpp = &pset->num_permitted_admin; 501 break; 502 default: 503 fatal("%s: invalid forwarding client %d", __func__, who); 504 } 505 } 506 507 /* Adds an entry to the spcified forwarding list */ 508 static int 509 permission_set_add(struct ssh *ssh, int who, int where, 510 const char *host_to_connect, int port_to_connect, 511 const char *listen_host, const char *listen_path, int listen_port, 512 Channel *downstream) 513 { 514 struct permission **permp; 515 u_int n, *npermp; 516 517 permission_set_get_array(ssh, who, where, &permp, &npermp); 518 519 if (*npermp >= INT_MAX) 520 fatal("%s: %s overflow", __func__, fwd_ident(who, where)); 521 522 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 523 n = (*npermp)++; 524 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 525 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 526 (*permp)[n].port_to_connect = port_to_connect; 527 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 528 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 529 (*permp)[n].listen_port = listen_port; 530 (*permp)[n].downstream = downstream; 531 #undef MAYBE_DUP 532 return (int)n; 533 } 534 535 static void 536 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 537 { 538 struct ssh_channels *sc = ssh->chanctxt; 539 struct permission_set *pset = &sc->local_perms; 540 struct permission *perm; 541 int r; 542 u_int i; 543 544 for (i = 0; i < pset->num_permitted_user; i++) { 545 perm = &pset->permitted_user[i]; 546 if (perm->downstream != c) 547 continue; 548 549 /* cancel on the server, since mux client is gone */ 550 debug("channel %d: cleanup remote forward for %s:%u", 551 c->self, perm->listen_host, perm->listen_port); 552 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 553 (r = sshpkt_put_cstring(ssh, 554 "cancel-tcpip-forward")) != 0 || 555 (r = sshpkt_put_u8(ssh, 0)) != 0 || 556 (r = sshpkt_put_cstring(ssh, 557 channel_rfwd_bind_host(perm->listen_host))) != 0 || 558 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 559 (r = sshpkt_send(ssh)) != 0) { 560 fatal("%s: channel %i: %s", __func__, 561 c->self, ssh_err(r)); 562 } 563 fwd_perm_clear(perm); /* unregister */ 564 } 565 } 566 567 /* Free the channel and close its fd/socket. */ 568 void 569 channel_free(struct ssh *ssh, Channel *c) 570 { 571 struct ssh_channels *sc = ssh->chanctxt; 572 char *s; 573 u_int i, n; 574 Channel *other; 575 struct channel_confirm *cc; 576 577 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 578 if ((other = sc->channels[i]) == NULL) 579 continue; 580 n++; 581 /* detach from mux client and prepare for closing */ 582 if (c->type == SSH_CHANNEL_MUX_CLIENT && 583 other->type == SSH_CHANNEL_MUX_PROXY && 584 other->mux_ctx == c) { 585 other->mux_ctx = NULL; 586 other->type = SSH_CHANNEL_OPEN; 587 other->istate = CHAN_INPUT_CLOSED; 588 other->ostate = CHAN_OUTPUT_CLOSED; 589 } 590 } 591 debug("channel %d: free: %s, nchannels %u", c->self, 592 c->remote_name ? c->remote_name : "???", n); 593 594 if (c->type == SSH_CHANNEL_MUX_CLIENT) 595 mux_remove_remote_forwardings(ssh, c); 596 597 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 598 s = channel_open_message(ssh); 599 debug3("channel %d: status: %s", c->self, s); 600 free(s); 601 } 602 603 channel_close_fds(ssh, c); 604 sshbuf_free(c->input); 605 sshbuf_free(c->output); 606 sshbuf_free(c->extended); 607 c->input = c->output = c->extended = NULL; 608 free(c->remote_name); 609 c->remote_name = NULL; 610 free(c->path); 611 c->path = NULL; 612 free(c->listening_addr); 613 c->listening_addr = NULL; 614 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 615 if (cc->abandon_cb != NULL) 616 cc->abandon_cb(ssh, c, cc->ctx); 617 TAILQ_REMOVE(&c->status_confirms, cc, entry); 618 explicit_bzero(cc, sizeof(*cc)); 619 free(cc); 620 } 621 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 622 c->filter_cleanup(ssh, c->self, c->filter_ctx); 623 sc->channels[c->self] = NULL; 624 explicit_bzero(c, sizeof(*c)); 625 free(c); 626 } 627 628 void 629 channel_free_all(struct ssh *ssh) 630 { 631 u_int i; 632 633 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 634 if (ssh->chanctxt->channels[i] != NULL) 635 channel_free(ssh, ssh->chanctxt->channels[i]); 636 } 637 638 /* 639 * Closes the sockets/fds of all channels. This is used to close extra file 640 * descriptors after a fork. 641 */ 642 void 643 channel_close_all(struct ssh *ssh) 644 { 645 u_int i; 646 647 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 648 if (ssh->chanctxt->channels[i] != NULL) 649 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 650 } 651 652 /* 653 * Stop listening to channels. 654 */ 655 void 656 channel_stop_listening(struct ssh *ssh) 657 { 658 u_int i; 659 Channel *c; 660 661 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 662 c = ssh->chanctxt->channels[i]; 663 if (c != NULL) { 664 switch (c->type) { 665 case SSH_CHANNEL_AUTH_SOCKET: 666 case SSH_CHANNEL_PORT_LISTENER: 667 case SSH_CHANNEL_RPORT_LISTENER: 668 case SSH_CHANNEL_X11_LISTENER: 669 case SSH_CHANNEL_UNIX_LISTENER: 670 case SSH_CHANNEL_RUNIX_LISTENER: 671 channel_close_fd(ssh, &c->sock); 672 channel_free(ssh, c); 673 break; 674 } 675 } 676 } 677 } 678 679 /* 680 * Returns true if no channel has too much buffered data, and false if one or 681 * more channel is overfull. 682 */ 683 int 684 channel_not_very_much_buffered_data(struct ssh *ssh) 685 { 686 u_int i; 687 u_int maxsize = ssh_packet_get_maxsize(ssh); 688 Channel *c; 689 690 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 691 c = ssh->chanctxt->channels[i]; 692 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 693 continue; 694 if (sshbuf_len(c->output) > maxsize) { 695 debug2("channel %d: big output buffer %zu > %u", 696 c->self, sshbuf_len(c->output), maxsize); 697 return 0; 698 } 699 } 700 return 1; 701 } 702 703 /* Returns true if any channel is still open. */ 704 int 705 channel_still_open(struct ssh *ssh) 706 { 707 u_int i; 708 Channel *c; 709 710 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 711 c = ssh->chanctxt->channels[i]; 712 if (c == NULL) 713 continue; 714 switch (c->type) { 715 case SSH_CHANNEL_X11_LISTENER: 716 case SSH_CHANNEL_PORT_LISTENER: 717 case SSH_CHANNEL_RPORT_LISTENER: 718 case SSH_CHANNEL_MUX_LISTENER: 719 case SSH_CHANNEL_CLOSED: 720 case SSH_CHANNEL_AUTH_SOCKET: 721 case SSH_CHANNEL_DYNAMIC: 722 case SSH_CHANNEL_RDYNAMIC_OPEN: 723 case SSH_CHANNEL_CONNECTING: 724 case SSH_CHANNEL_ZOMBIE: 725 case SSH_CHANNEL_ABANDONED: 726 case SSH_CHANNEL_UNIX_LISTENER: 727 case SSH_CHANNEL_RUNIX_LISTENER: 728 continue; 729 case SSH_CHANNEL_LARVAL: 730 continue; 731 case SSH_CHANNEL_OPENING: 732 case SSH_CHANNEL_OPEN: 733 case SSH_CHANNEL_RDYNAMIC_FINISH: 734 case SSH_CHANNEL_X11_OPEN: 735 case SSH_CHANNEL_MUX_CLIENT: 736 case SSH_CHANNEL_MUX_PROXY: 737 return 1; 738 default: 739 fatal("%s: bad channel type %d", __func__, c->type); 740 /* NOTREACHED */ 741 } 742 } 743 return 0; 744 } 745 746 /* Returns the id of an open channel suitable for keepaliving */ 747 int 748 channel_find_open(struct ssh *ssh) 749 { 750 u_int i; 751 Channel *c; 752 753 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 754 c = ssh->chanctxt->channels[i]; 755 if (c == NULL || !c->have_remote_id) 756 continue; 757 switch (c->type) { 758 case SSH_CHANNEL_CLOSED: 759 case SSH_CHANNEL_DYNAMIC: 760 case SSH_CHANNEL_RDYNAMIC_OPEN: 761 case SSH_CHANNEL_RDYNAMIC_FINISH: 762 case SSH_CHANNEL_X11_LISTENER: 763 case SSH_CHANNEL_PORT_LISTENER: 764 case SSH_CHANNEL_RPORT_LISTENER: 765 case SSH_CHANNEL_MUX_LISTENER: 766 case SSH_CHANNEL_MUX_CLIENT: 767 case SSH_CHANNEL_MUX_PROXY: 768 case SSH_CHANNEL_OPENING: 769 case SSH_CHANNEL_CONNECTING: 770 case SSH_CHANNEL_ZOMBIE: 771 case SSH_CHANNEL_ABANDONED: 772 case SSH_CHANNEL_UNIX_LISTENER: 773 case SSH_CHANNEL_RUNIX_LISTENER: 774 continue; 775 case SSH_CHANNEL_LARVAL: 776 case SSH_CHANNEL_AUTH_SOCKET: 777 case SSH_CHANNEL_OPEN: 778 case SSH_CHANNEL_X11_OPEN: 779 return i; 780 default: 781 fatal("%s: bad channel type %d", __func__, c->type); 782 /* NOTREACHED */ 783 } 784 } 785 return -1; 786 } 787 788 /* Returns the state of the channel's extended usage flag */ 789 const char * 790 channel_format_extended_usage(const Channel *c) 791 { 792 if (c->efd == -1) 793 return "closed"; 794 795 switch (c->extended_usage) { 796 case CHAN_EXTENDED_WRITE: 797 return "write"; 798 case CHAN_EXTENDED_READ: 799 return "read"; 800 case CHAN_EXTENDED_IGNORE: 801 return "ignore"; 802 default: 803 return "UNKNOWN"; 804 } 805 } 806 807 static char * 808 channel_format_status(const Channel *c) 809 { 810 char *ret = NULL; 811 812 xasprintf(&ret, "t%d %s%u i%u/%zu o%u/%zu e[%s]/%zu " 813 "fd %d/%d/%d sock %d cc %d", 814 c->type, 815 c->have_remote_id ? "r" : "nr", c->remote_id, 816 c->istate, sshbuf_len(c->input), 817 c->ostate, sshbuf_len(c->output), 818 channel_format_extended_usage(c), sshbuf_len(c->extended), 819 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan); 820 return ret; 821 } 822 823 /* 824 * Returns a message describing the currently open forwarded connections, 825 * suitable for sending to the client. The message contains crlf pairs for 826 * newlines. 827 */ 828 char * 829 channel_open_message(struct ssh *ssh) 830 { 831 struct sshbuf *buf; 832 Channel *c; 833 u_int i; 834 int r; 835 char *cp, *ret; 836 837 if ((buf = sshbuf_new()) == NULL) 838 fatal("%s: sshbuf_new", __func__); 839 if ((r = sshbuf_putf(buf, 840 "The following connections are open:\r\n")) != 0) 841 fatal("%s: sshbuf_putf: %s", __func__, ssh_err(r)); 842 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 843 c = ssh->chanctxt->channels[i]; 844 if (c == NULL) 845 continue; 846 switch (c->type) { 847 case SSH_CHANNEL_X11_LISTENER: 848 case SSH_CHANNEL_PORT_LISTENER: 849 case SSH_CHANNEL_RPORT_LISTENER: 850 case SSH_CHANNEL_CLOSED: 851 case SSH_CHANNEL_AUTH_SOCKET: 852 case SSH_CHANNEL_ZOMBIE: 853 case SSH_CHANNEL_ABANDONED: 854 case SSH_CHANNEL_MUX_LISTENER: 855 case SSH_CHANNEL_UNIX_LISTENER: 856 case SSH_CHANNEL_RUNIX_LISTENER: 857 continue; 858 case SSH_CHANNEL_LARVAL: 859 case SSH_CHANNEL_OPENING: 860 case SSH_CHANNEL_CONNECTING: 861 case SSH_CHANNEL_DYNAMIC: 862 case SSH_CHANNEL_RDYNAMIC_OPEN: 863 case SSH_CHANNEL_RDYNAMIC_FINISH: 864 case SSH_CHANNEL_OPEN: 865 case SSH_CHANNEL_X11_OPEN: 866 case SSH_CHANNEL_MUX_PROXY: 867 case SSH_CHANNEL_MUX_CLIENT: 868 cp = channel_format_status(c); 869 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 870 c->self, c->remote_name, cp)) != 0) { 871 free(cp); 872 fatal("%s: sshbuf_putf: %s", 873 __func__, ssh_err(r)); 874 } 875 free(cp); 876 continue; 877 default: 878 fatal("%s: bad channel type %d", __func__, c->type); 879 /* NOTREACHED */ 880 } 881 } 882 if ((ret = sshbuf_dup_string(buf)) == NULL) 883 fatal("%s: sshbuf_dup_string", __func__); 884 sshbuf_free(buf); 885 return ret; 886 } 887 888 static void 889 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 890 { 891 int r; 892 893 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 894 (r = sshpkt_put_cstring(ssh, type)) != 0 || 895 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 896 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 897 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 898 fatal("%s: channel %i: open: %s", where, c->self, ssh_err(r)); 899 } 900 } 901 902 void 903 channel_send_open(struct ssh *ssh, int id) 904 { 905 Channel *c = channel_lookup(ssh, id); 906 int r; 907 908 if (c == NULL) { 909 logit("channel_send_open: %d: bad id", id); 910 return; 911 } 912 debug2("channel %d: send open", id); 913 open_preamble(ssh, __func__, c, c->ctype); 914 if ((r = sshpkt_send(ssh)) != 0) 915 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 916 } 917 918 void 919 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 920 { 921 Channel *c = channel_lookup(ssh, id); 922 int r; 923 924 if (c == NULL) { 925 logit("%s: %d: unknown channel id", __func__, id); 926 return; 927 } 928 if (!c->have_remote_id) 929 fatal(":%s: channel %d: no remote id", __func__, c->self); 930 931 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 932 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 933 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 934 (r = sshpkt_put_cstring(ssh, service)) != 0 || 935 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 936 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 937 } 938 } 939 940 void 941 channel_register_status_confirm(struct ssh *ssh, int id, 942 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 943 { 944 struct channel_confirm *cc; 945 Channel *c; 946 947 if ((c = channel_lookup(ssh, id)) == NULL) 948 fatal("%s: %d: bad id", __func__, id); 949 950 cc = xcalloc(1, sizeof(*cc)); 951 cc->cb = cb; 952 cc->abandon_cb = abandon_cb; 953 cc->ctx = ctx; 954 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 955 } 956 957 void 958 channel_register_open_confirm(struct ssh *ssh, int id, 959 channel_open_fn *fn, void *ctx) 960 { 961 Channel *c = channel_lookup(ssh, id); 962 963 if (c == NULL) { 964 logit("%s: %d: bad id", __func__, id); 965 return; 966 } 967 c->open_confirm = fn; 968 c->open_confirm_ctx = ctx; 969 } 970 971 void 972 channel_register_cleanup(struct ssh *ssh, int id, 973 channel_callback_fn *fn, int do_close) 974 { 975 Channel *c = channel_by_id(ssh, id); 976 977 if (c == NULL) { 978 logit("%s: %d: bad id", __func__, id); 979 return; 980 } 981 c->detach_user = fn; 982 c->detach_close = do_close; 983 } 984 985 void 986 channel_cancel_cleanup(struct ssh *ssh, int id) 987 { 988 Channel *c = channel_by_id(ssh, id); 989 990 if (c == NULL) { 991 logit("%s: %d: bad id", __func__, id); 992 return; 993 } 994 c->detach_user = NULL; 995 c->detach_close = 0; 996 } 997 998 void 999 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1000 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1001 { 1002 Channel *c = channel_lookup(ssh, id); 1003 1004 if (c == NULL) { 1005 logit("%s: %d: bad id", __func__, id); 1006 return; 1007 } 1008 c->input_filter = ifn; 1009 c->output_filter = ofn; 1010 c->filter_ctx = ctx; 1011 c->filter_cleanup = cfn; 1012 } 1013 1014 void 1015 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1016 int extusage, int nonblock, int is_tty, u_int window_max) 1017 { 1018 Channel *c = channel_lookup(ssh, id); 1019 int r; 1020 1021 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1022 fatal("channel_activate for non-larval channel %d.", id); 1023 if (!c->have_remote_id) 1024 fatal(":%s: channel %d: no remote id", __func__, c->self); 1025 1026 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1027 c->type = SSH_CHANNEL_OPEN; 1028 c->local_window = c->local_window_max = window_max; 1029 1030 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1031 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1032 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1033 (r = sshpkt_send(ssh)) != 0) 1034 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 1035 } 1036 1037 static void 1038 channel_pre_listener(struct ssh *ssh, Channel *c, 1039 fd_set *readset, fd_set *writeset) 1040 { 1041 FD_SET(c->sock, readset); 1042 } 1043 1044 static void 1045 channel_pre_connecting(struct ssh *ssh, Channel *c, 1046 fd_set *readset, fd_set *writeset) 1047 { 1048 debug3("channel %d: waiting for connection", c->self); 1049 FD_SET(c->sock, writeset); 1050 } 1051 1052 static void 1053 channel_pre_open(struct ssh *ssh, Channel *c, 1054 fd_set *readset, fd_set *writeset) 1055 { 1056 if (c->istate == CHAN_INPUT_OPEN && 1057 c->remote_window > 0 && 1058 sshbuf_len(c->input) < c->remote_window && 1059 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1060 FD_SET(c->rfd, readset); 1061 if (c->ostate == CHAN_OUTPUT_OPEN || 1062 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1063 if (sshbuf_len(c->output) > 0) { 1064 FD_SET(c->wfd, writeset); 1065 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1066 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1067 debug2("channel %d: " 1068 "obuf_empty delayed efd %d/(%zu)", c->self, 1069 c->efd, sshbuf_len(c->extended)); 1070 else 1071 chan_obuf_empty(ssh, c); 1072 } 1073 } 1074 /** XXX check close conditions, too */ 1075 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1076 c->ostate == CHAN_OUTPUT_CLOSED)) { 1077 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1078 sshbuf_len(c->extended) > 0) 1079 FD_SET(c->efd, writeset); 1080 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1081 (c->extended_usage == CHAN_EXTENDED_READ || 1082 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1083 sshbuf_len(c->extended) < c->remote_window) 1084 FD_SET(c->efd, readset); 1085 } 1086 /* XXX: What about efd? races? */ 1087 } 1088 1089 /* 1090 * This is a special state for X11 authentication spoofing. An opened X11 1091 * connection (when authentication spoofing is being done) remains in this 1092 * state until the first packet has been completely read. The authentication 1093 * data in that packet is then substituted by the real data if it matches the 1094 * fake data, and the channel is put into normal mode. 1095 * XXX All this happens at the client side. 1096 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1097 */ 1098 static int 1099 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1100 { 1101 struct ssh_channels *sc = ssh->chanctxt; 1102 u_char *ucp; 1103 u_int proto_len, data_len; 1104 1105 /* Is this being called after the refusal deadline? */ 1106 if (sc->x11_refuse_time != 0 && 1107 (u_int)monotime() >= sc->x11_refuse_time) { 1108 verbose("Rejected X11 connection after ForwardX11Timeout " 1109 "expired"); 1110 return -1; 1111 } 1112 1113 /* Check if the fixed size part of the packet is in buffer. */ 1114 if (sshbuf_len(b) < 12) 1115 return 0; 1116 1117 /* Parse the lengths of variable-length fields. */ 1118 ucp = sshbuf_mutable_ptr(b); 1119 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1120 proto_len = 256 * ucp[6] + ucp[7]; 1121 data_len = 256 * ucp[8] + ucp[9]; 1122 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1123 proto_len = ucp[6] + 256 * ucp[7]; 1124 data_len = ucp[8] + 256 * ucp[9]; 1125 } else { 1126 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1127 ucp[0]); 1128 return -1; 1129 } 1130 1131 /* Check if the whole packet is in buffer. */ 1132 if (sshbuf_len(b) < 1133 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1134 return 0; 1135 1136 /* Check if authentication protocol matches. */ 1137 if (proto_len != strlen(sc->x11_saved_proto) || 1138 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1139 debug2("X11 connection uses different authentication protocol."); 1140 return -1; 1141 } 1142 /* Check if authentication data matches our fake data. */ 1143 if (data_len != sc->x11_fake_data_len || 1144 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1145 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1146 debug2("X11 auth data does not match fake data."); 1147 return -1; 1148 } 1149 /* Check fake data length */ 1150 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1151 error("X11 fake_data_len %d != saved_data_len %d", 1152 sc->x11_fake_data_len, sc->x11_saved_data_len); 1153 return -1; 1154 } 1155 /* 1156 * Received authentication protocol and data match 1157 * our fake data. Substitute the fake data with real 1158 * data. 1159 */ 1160 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1161 sc->x11_saved_data, sc->x11_saved_data_len); 1162 return 1; 1163 } 1164 1165 static void 1166 channel_pre_x11_open(struct ssh *ssh, Channel *c, 1167 fd_set *readset, fd_set *writeset) 1168 { 1169 int ret = x11_open_helper(ssh, c->output); 1170 1171 /* c->force_drain = 1; */ 1172 1173 if (ret == 1) { 1174 c->type = SSH_CHANNEL_OPEN; 1175 channel_pre_open(ssh, c, readset, writeset); 1176 } else if (ret == -1) { 1177 logit("X11 connection rejected because of wrong authentication."); 1178 debug2("X11 rejected %d i%d/o%d", 1179 c->self, c->istate, c->ostate); 1180 chan_read_failed(ssh, c); 1181 sshbuf_reset(c->input); 1182 chan_ibuf_empty(ssh, c); 1183 sshbuf_reset(c->output); 1184 chan_write_failed(ssh, c); 1185 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1186 } 1187 } 1188 1189 static void 1190 channel_pre_mux_client(struct ssh *ssh, 1191 Channel *c, fd_set *readset, fd_set *writeset) 1192 { 1193 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1194 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1195 FD_SET(c->rfd, readset); 1196 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1197 /* clear buffer immediately (discard any partial packet) */ 1198 sshbuf_reset(c->input); 1199 chan_ibuf_empty(ssh, c); 1200 /* Start output drain. XXX just kill chan? */ 1201 chan_rcvd_oclose(ssh, c); 1202 } 1203 if (c->ostate == CHAN_OUTPUT_OPEN || 1204 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1205 if (sshbuf_len(c->output) > 0) 1206 FD_SET(c->wfd, writeset); 1207 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1208 chan_obuf_empty(ssh, c); 1209 } 1210 } 1211 1212 /* try to decode a socks4 header */ 1213 static int 1214 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1215 { 1216 const u_char *p; 1217 char *host; 1218 u_int len, have, i, found, need; 1219 char username[256]; 1220 struct { 1221 u_int8_t version; 1222 u_int8_t command; 1223 u_int16_t dest_port; 1224 struct in_addr dest_addr; 1225 } s4_req, s4_rsp; 1226 int r; 1227 1228 debug2("channel %d: decode socks4", c->self); 1229 1230 have = sshbuf_len(input); 1231 len = sizeof(s4_req); 1232 if (have < len) 1233 return 0; 1234 p = sshbuf_ptr(input); 1235 1236 need = 1; 1237 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1238 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1239 debug2("channel %d: socks4a request", c->self); 1240 /* ... and needs an extra string (the hostname) */ 1241 need = 2; 1242 } 1243 /* Check for terminating NUL on the string(s) */ 1244 for (found = 0, i = len; i < have; i++) { 1245 if (p[i] == '\0') { 1246 found++; 1247 if (found == need) 1248 break; 1249 } 1250 if (i > 1024) { 1251 /* the peer is probably sending garbage */ 1252 debug("channel %d: decode socks4: too long", 1253 c->self); 1254 return -1; 1255 } 1256 } 1257 if (found < need) 1258 return 0; 1259 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1260 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1261 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1262 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1263 debug("channels %d: decode socks4: %s", c->self, ssh_err(r)); 1264 return -1; 1265 } 1266 have = sshbuf_len(input); 1267 p = sshbuf_ptr(input); 1268 if (memchr(p, '\0', have) == NULL) { 1269 error("channel %d: decode socks4: user not nul terminated", 1270 c->self); 1271 return -1; 1272 } 1273 len = strlen(p); 1274 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1275 len++; /* trailing '\0' */ 1276 strlcpy(username, p, sizeof(username)); 1277 if ((r = sshbuf_consume(input, len)) != 0) { 1278 fatal("%s: channel %d: consume: %s", __func__, 1279 c->self, ssh_err(r)); 1280 } 1281 free(c->path); 1282 c->path = NULL; 1283 if (need == 1) { /* SOCKS4: one string */ 1284 host = inet_ntoa(s4_req.dest_addr); 1285 c->path = xstrdup(host); 1286 } else { /* SOCKS4A: two strings */ 1287 have = sshbuf_len(input); 1288 p = sshbuf_ptr(input); 1289 if (memchr(p, '\0', have) == NULL) { 1290 error("channel %d: decode socks4a: host not nul " 1291 "terminated", c->self); 1292 return -1; 1293 } 1294 len = strlen(p); 1295 debug2("channel %d: decode socks4a: host %s/%d", 1296 c->self, p, len); 1297 len++; /* trailing '\0' */ 1298 if (len > NI_MAXHOST) { 1299 error("channel %d: hostname \"%.100s\" too long", 1300 c->self, p); 1301 return -1; 1302 } 1303 c->path = xstrdup(p); 1304 if ((r = sshbuf_consume(input, len)) != 0) { 1305 fatal("%s: channel %d: consume: %s", __func__, 1306 c->self, ssh_err(r)); 1307 } 1308 } 1309 c->host_port = ntohs(s4_req.dest_port); 1310 1311 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1312 c->self, c->path, c->host_port, s4_req.command); 1313 1314 if (s4_req.command != 1) { 1315 debug("channel %d: cannot handle: %s cn %d", 1316 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1317 return -1; 1318 } 1319 s4_rsp.version = 0; /* vn: 0 for reply */ 1320 s4_rsp.command = 90; /* cd: req granted */ 1321 s4_rsp.dest_port = 0; /* ignored */ 1322 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1323 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) { 1324 fatal("%s: channel %d: append reply: %s", __func__, 1325 c->self, ssh_err(r)); 1326 } 1327 return 1; 1328 } 1329 1330 /* try to decode a socks5 header */ 1331 #define SSH_SOCKS5_AUTHDONE 0x1000 1332 #define SSH_SOCKS5_NOAUTH 0x00 1333 #define SSH_SOCKS5_IPV4 0x01 1334 #define SSH_SOCKS5_DOMAIN 0x03 1335 #define SSH_SOCKS5_IPV6 0x04 1336 #define SSH_SOCKS5_CONNECT 0x01 1337 #define SSH_SOCKS5_SUCCESS 0x00 1338 1339 static int 1340 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1341 { 1342 /* XXX use get/put_u8 instead of trusting struct padding */ 1343 struct { 1344 u_int8_t version; 1345 u_int8_t command; 1346 u_int8_t reserved; 1347 u_int8_t atyp; 1348 } s5_req, s5_rsp; 1349 u_int16_t dest_port; 1350 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1351 const u_char *p; 1352 u_int have, need, i, found, nmethods, addrlen, af; 1353 int r; 1354 1355 debug2("channel %d: decode socks5", c->self); 1356 p = sshbuf_ptr(input); 1357 if (p[0] != 0x05) 1358 return -1; 1359 have = sshbuf_len(input); 1360 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1361 /* format: ver | nmethods | methods */ 1362 if (have < 2) 1363 return 0; 1364 nmethods = p[1]; 1365 if (have < nmethods + 2) 1366 return 0; 1367 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1368 for (found = 0, i = 2; i < nmethods + 2; i++) { 1369 if (p[i] == SSH_SOCKS5_NOAUTH) { 1370 found = 1; 1371 break; 1372 } 1373 } 1374 if (!found) { 1375 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1376 c->self); 1377 return -1; 1378 } 1379 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) { 1380 fatal("%s: channel %d: consume: %s", __func__, 1381 c->self, ssh_err(r)); 1382 } 1383 /* version, method */ 1384 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1385 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) { 1386 fatal("%s: channel %d: append reply: %s", __func__, 1387 c->self, ssh_err(r)); 1388 } 1389 c->flags |= SSH_SOCKS5_AUTHDONE; 1390 debug2("channel %d: socks5 auth done", c->self); 1391 return 0; /* need more */ 1392 } 1393 debug2("channel %d: socks5 post auth", c->self); 1394 if (have < sizeof(s5_req)+1) 1395 return 0; /* need more */ 1396 memcpy(&s5_req, p, sizeof(s5_req)); 1397 if (s5_req.version != 0x05 || 1398 s5_req.command != SSH_SOCKS5_CONNECT || 1399 s5_req.reserved != 0x00) { 1400 debug2("channel %d: only socks5 connect supported", c->self); 1401 return -1; 1402 } 1403 switch (s5_req.atyp){ 1404 case SSH_SOCKS5_IPV4: 1405 addrlen = 4; 1406 af = AF_INET; 1407 break; 1408 case SSH_SOCKS5_DOMAIN: 1409 addrlen = p[sizeof(s5_req)]; 1410 af = -1; 1411 break; 1412 case SSH_SOCKS5_IPV6: 1413 addrlen = 16; 1414 af = AF_INET6; 1415 break; 1416 default: 1417 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1418 return -1; 1419 } 1420 need = sizeof(s5_req) + addrlen + 2; 1421 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1422 need++; 1423 if (have < need) 1424 return 0; 1425 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) { 1426 fatal("%s: channel %d: consume: %s", __func__, 1427 c->self, ssh_err(r)); 1428 } 1429 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1430 /* host string length */ 1431 if ((r = sshbuf_consume(input, 1)) != 0) { 1432 fatal("%s: channel %d: consume: %s", __func__, 1433 c->self, ssh_err(r)); 1434 } 1435 } 1436 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1437 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1438 debug("channel %d: parse addr/port: %s", c->self, ssh_err(r)); 1439 return -1; 1440 } 1441 dest_addr[addrlen] = '\0'; 1442 free(c->path); 1443 c->path = NULL; 1444 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1445 if (addrlen >= NI_MAXHOST) { 1446 error("channel %d: dynamic request: socks5 hostname " 1447 "\"%.100s\" too long", c->self, dest_addr); 1448 return -1; 1449 } 1450 c->path = xstrdup(dest_addr); 1451 } else { 1452 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1453 return -1; 1454 c->path = xstrdup(ntop); 1455 } 1456 c->host_port = ntohs(dest_port); 1457 1458 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1459 c->self, c->path, c->host_port, s5_req.command); 1460 1461 s5_rsp.version = 0x05; 1462 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1463 s5_rsp.reserved = 0; /* ignored */ 1464 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1465 dest_port = 0; /* ignored */ 1466 1467 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1468 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1469 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1470 fatal("%s: channel %d: append reply: %s", __func__, 1471 c->self, ssh_err(r)); 1472 return 1; 1473 } 1474 1475 Channel * 1476 channel_connect_stdio_fwd(struct ssh *ssh, 1477 const char *host_to_connect, u_short port_to_connect, int in, int out) 1478 { 1479 Channel *c; 1480 1481 debug("%s %s:%d", __func__, host_to_connect, port_to_connect); 1482 1483 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1484 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1485 0, "stdio-forward", /*nonblock*/0); 1486 1487 c->path = xstrdup(host_to_connect); 1488 c->host_port = port_to_connect; 1489 c->listening_port = 0; 1490 c->force_drain = 1; 1491 1492 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1493 port_open_helper(ssh, c, "direct-tcpip"); 1494 1495 return c; 1496 } 1497 1498 /* dynamic port forwarding */ 1499 static void 1500 channel_pre_dynamic(struct ssh *ssh, Channel *c, 1501 fd_set *readset, fd_set *writeset) 1502 { 1503 const u_char *p; 1504 u_int have; 1505 int ret; 1506 1507 have = sshbuf_len(c->input); 1508 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1509 /* sshbuf_dump(c->input, stderr); */ 1510 /* check if the fixed size part of the packet is in buffer. */ 1511 if (have < 3) { 1512 /* need more */ 1513 FD_SET(c->sock, readset); 1514 return; 1515 } 1516 /* try to guess the protocol */ 1517 p = sshbuf_ptr(c->input); 1518 /* XXX sshbuf_peek_u8? */ 1519 switch (p[0]) { 1520 case 0x04: 1521 ret = channel_decode_socks4(c, c->input, c->output); 1522 break; 1523 case 0x05: 1524 ret = channel_decode_socks5(c, c->input, c->output); 1525 break; 1526 default: 1527 ret = -1; 1528 break; 1529 } 1530 if (ret < 0) { 1531 chan_mark_dead(ssh, c); 1532 } else if (ret == 0) { 1533 debug2("channel %d: pre_dynamic: need more", c->self); 1534 /* need more */ 1535 FD_SET(c->sock, readset); 1536 if (sshbuf_len(c->output)) 1537 FD_SET(c->sock, writeset); 1538 } else { 1539 /* switch to the next state */ 1540 c->type = SSH_CHANNEL_OPENING; 1541 port_open_helper(ssh, c, "direct-tcpip"); 1542 } 1543 } 1544 1545 /* simulate read-error */ 1546 static void 1547 rdynamic_close(struct ssh *ssh, Channel *c) 1548 { 1549 c->type = SSH_CHANNEL_OPEN; 1550 chan_read_failed(ssh, c); 1551 sshbuf_reset(c->input); 1552 chan_ibuf_empty(ssh, c); 1553 sshbuf_reset(c->output); 1554 chan_write_failed(ssh, c); 1555 } 1556 1557 /* reverse dynamic port forwarding */ 1558 static void 1559 channel_before_prepare_select_rdynamic(struct ssh *ssh, Channel *c) 1560 { 1561 const u_char *p; 1562 u_int have, len; 1563 int r, ret; 1564 1565 have = sshbuf_len(c->output); 1566 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1567 /* sshbuf_dump(c->output, stderr); */ 1568 /* EOF received */ 1569 if (c->flags & CHAN_EOF_RCVD) { 1570 if ((r = sshbuf_consume(c->output, have)) != 0) { 1571 fatal("%s: channel %d: consume: %s", 1572 __func__, c->self, ssh_err(r)); 1573 } 1574 rdynamic_close(ssh, c); 1575 return; 1576 } 1577 /* check if the fixed size part of the packet is in buffer. */ 1578 if (have < 3) 1579 return; 1580 /* try to guess the protocol */ 1581 p = sshbuf_ptr(c->output); 1582 switch (p[0]) { 1583 case 0x04: 1584 /* switch input/output for reverse forwarding */ 1585 ret = channel_decode_socks4(c, c->output, c->input); 1586 break; 1587 case 0x05: 1588 ret = channel_decode_socks5(c, c->output, c->input); 1589 break; 1590 default: 1591 ret = -1; 1592 break; 1593 } 1594 if (ret < 0) { 1595 rdynamic_close(ssh, c); 1596 } else if (ret == 0) { 1597 debug2("channel %d: pre_rdynamic: need more", c->self); 1598 /* send socks request to peer */ 1599 len = sshbuf_len(c->input); 1600 if (len > 0 && len < c->remote_window) { 1601 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1602 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1603 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1604 (r = sshpkt_send(ssh)) != 0) { 1605 fatal("%s: channel %i: rdynamic: %s", __func__, 1606 c->self, ssh_err(r)); 1607 } 1608 if ((r = sshbuf_consume(c->input, len)) != 0) { 1609 fatal("%s: channel %d: consume: %s", 1610 __func__, c->self, ssh_err(r)); 1611 } 1612 c->remote_window -= len; 1613 } 1614 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1615 /* the connect failed */ 1616 rdynamic_close(ssh, c); 1617 } 1618 } 1619 1620 /* This is our fake X11 server socket. */ 1621 static void 1622 channel_post_x11_listener(struct ssh *ssh, Channel *c, 1623 fd_set *readset, fd_set *writeset) 1624 { 1625 Channel *nc; 1626 struct sockaddr_storage addr; 1627 int r, newsock, oerrno, remote_port; 1628 socklen_t addrlen; 1629 char buf[16384], *remote_ipaddr; 1630 1631 if (!FD_ISSET(c->sock, readset)) 1632 return; 1633 1634 debug("X11 connection requested."); 1635 addrlen = sizeof(addr); 1636 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1637 if (c->single_connection) { 1638 oerrno = errno; 1639 debug2("single_connection: closing X11 listener."); 1640 channel_close_fd(ssh, &c->sock); 1641 chan_mark_dead(ssh, c); 1642 errno = oerrno; 1643 } 1644 if (newsock < 0) { 1645 if (errno != EINTR && errno != EWOULDBLOCK && 1646 errno != ECONNABORTED) 1647 error("accept: %.100s", strerror(errno)); 1648 if (errno == EMFILE || errno == ENFILE) 1649 c->notbefore = monotime() + 1; 1650 return; 1651 } 1652 set_nodelay(newsock); 1653 remote_ipaddr = get_peer_ipaddr(newsock); 1654 remote_port = get_peer_port(newsock); 1655 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1656 remote_ipaddr, remote_port); 1657 1658 nc = channel_new(ssh, "accepted x11 socket", 1659 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1660 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1661 open_preamble(ssh, __func__, nc, "x11"); 1662 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1663 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1664 fatal("%s: channel %i: reply %s", __func__, 1665 c->self, ssh_err(r)); 1666 } 1667 if ((r = sshpkt_send(ssh)) != 0) 1668 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); 1669 free(remote_ipaddr); 1670 } 1671 1672 static void 1673 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1674 { 1675 char *local_ipaddr = get_local_ipaddr(c->sock); 1676 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1677 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1678 int remote_port = get_peer_port(c->sock); 1679 int r; 1680 1681 if (remote_port == -1) { 1682 /* Fake addr/port to appease peers that validate it (Tectia) */ 1683 free(remote_ipaddr); 1684 remote_ipaddr = xstrdup("127.0.0.1"); 1685 remote_port = 65535; 1686 } 1687 1688 free(c->remote_name); 1689 xasprintf(&c->remote_name, 1690 "%s: listening port %d for %.100s port %d, " 1691 "connect from %.200s port %d to %.100s port %d", 1692 rtype, c->listening_port, c->path, c->host_port, 1693 remote_ipaddr, remote_port, local_ipaddr, local_port); 1694 1695 open_preamble(ssh, __func__, c, rtype); 1696 if (strcmp(rtype, "direct-tcpip") == 0) { 1697 /* target host, port */ 1698 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1699 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) { 1700 fatal("%s: channel %i: reply %s", __func__, 1701 c->self, ssh_err(r)); 1702 } 1703 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1704 /* target path */ 1705 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { 1706 fatal("%s: channel %i: reply %s", __func__, 1707 c->self, ssh_err(r)); 1708 } 1709 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1710 /* listen path */ 1711 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { 1712 fatal("%s: channel %i: reply %s", __func__, 1713 c->self, ssh_err(r)); 1714 } 1715 } else { 1716 /* listen address, port */ 1717 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1718 (r = sshpkt_put_u32(ssh, local_port)) != 0) { 1719 fatal("%s: channel %i: reply %s", __func__, 1720 c->self, ssh_err(r)); 1721 } 1722 } 1723 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1724 /* reserved for future owner/mode info */ 1725 if ((r = sshpkt_put_cstring(ssh, "")) != 0) { 1726 fatal("%s: channel %i: reply %s", __func__, 1727 c->self, ssh_err(r)); 1728 } 1729 } else { 1730 /* originator host and port */ 1731 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1732 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) { 1733 fatal("%s: channel %i: reply %s", __func__, 1734 c->self, ssh_err(r)); 1735 } 1736 } 1737 if ((r = sshpkt_send(ssh)) != 0) 1738 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); 1739 free(remote_ipaddr); 1740 free(local_ipaddr); 1741 } 1742 1743 void 1744 channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time) 1745 { 1746 ssh->chanctxt->x11_refuse_time = refuse_time; 1747 } 1748 1749 /* 1750 * This socket is listening for connections to a forwarded TCP/IP port. 1751 */ 1752 static void 1753 channel_post_port_listener(struct ssh *ssh, Channel *c, 1754 fd_set *readset, fd_set *writeset) 1755 { 1756 Channel *nc; 1757 struct sockaddr_storage addr; 1758 int newsock, nextstate; 1759 socklen_t addrlen; 1760 char *rtype; 1761 1762 if (!FD_ISSET(c->sock, readset)) 1763 return; 1764 1765 debug("Connection to port %d forwarding to %.100s port %d requested.", 1766 c->listening_port, c->path, c->host_port); 1767 1768 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1769 nextstate = SSH_CHANNEL_OPENING; 1770 rtype = "forwarded-tcpip"; 1771 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1772 nextstate = SSH_CHANNEL_OPENING; 1773 rtype = "forwarded-streamlocal@openssh.com"; 1774 } else if (c->host_port == PORT_STREAMLOCAL) { 1775 nextstate = SSH_CHANNEL_OPENING; 1776 rtype = "direct-streamlocal@openssh.com"; 1777 } else if (c->host_port == 0) { 1778 nextstate = SSH_CHANNEL_DYNAMIC; 1779 rtype = "dynamic-tcpip"; 1780 } else { 1781 nextstate = SSH_CHANNEL_OPENING; 1782 rtype = "direct-tcpip"; 1783 } 1784 1785 addrlen = sizeof(addr); 1786 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1787 if (newsock < 0) { 1788 if (errno != EINTR && errno != EWOULDBLOCK && 1789 errno != ECONNABORTED) 1790 error("accept: %.100s", strerror(errno)); 1791 if (errno == EMFILE || errno == ENFILE) 1792 c->notbefore = monotime() + 1; 1793 return; 1794 } 1795 if (c->host_port != PORT_STREAMLOCAL) 1796 set_nodelay(newsock); 1797 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1798 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1799 nc->listening_port = c->listening_port; 1800 nc->host_port = c->host_port; 1801 if (c->path != NULL) 1802 nc->path = xstrdup(c->path); 1803 1804 if (nextstate != SSH_CHANNEL_DYNAMIC) 1805 port_open_helper(ssh, nc, rtype); 1806 } 1807 1808 /* 1809 * This is the authentication agent socket listening for connections from 1810 * clients. 1811 */ 1812 static void 1813 channel_post_auth_listener(struct ssh *ssh, Channel *c, 1814 fd_set *readset, fd_set *writeset) 1815 { 1816 Channel *nc; 1817 int r, newsock; 1818 struct sockaddr_storage addr; 1819 socklen_t addrlen; 1820 1821 if (!FD_ISSET(c->sock, readset)) 1822 return; 1823 1824 addrlen = sizeof(addr); 1825 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1826 if (newsock < 0) { 1827 error("accept from auth socket: %.100s", strerror(errno)); 1828 if (errno == EMFILE || errno == ENFILE) 1829 c->notbefore = monotime() + 1; 1830 return; 1831 } 1832 nc = channel_new(ssh, "accepted auth socket", 1833 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1834 c->local_window_max, c->local_maxpacket, 1835 0, "accepted auth socket", 1); 1836 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1837 if ((r = sshpkt_send(ssh)) != 0) 1838 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 1839 } 1840 1841 static void 1842 channel_post_connecting(struct ssh *ssh, Channel *c, 1843 fd_set *readset, fd_set *writeset) 1844 { 1845 int err = 0, sock, isopen, r; 1846 socklen_t sz = sizeof(err); 1847 1848 if (!FD_ISSET(c->sock, writeset)) 1849 return; 1850 if (!c->have_remote_id) 1851 fatal(":%s: channel %d: no remote id", __func__, c->self); 1852 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1853 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1854 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { 1855 err = errno; 1856 error("getsockopt SO_ERROR failed"); 1857 } 1858 if (err == 0) { 1859 debug("channel %d: connected to %s port %d", 1860 c->self, c->connect_ctx.host, c->connect_ctx.port); 1861 channel_connect_ctx_free(&c->connect_ctx); 1862 c->type = SSH_CHANNEL_OPEN; 1863 if (isopen) { 1864 /* no message necessary */ 1865 } else { 1866 if ((r = sshpkt_start(ssh, 1867 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1868 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1869 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1870 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1871 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) 1872 != 0) 1873 fatal("%s: channel %i: confirm: %s", __func__, 1874 c->self, ssh_err(r)); 1875 if ((r = sshpkt_send(ssh)) != 0) 1876 fatal("%s: channel %i: %s", __func__, c->self, 1877 ssh_err(r)); 1878 } 1879 } else { 1880 debug("channel %d: connection failed: %s", 1881 c->self, strerror(err)); 1882 /* Try next address, if any */ 1883 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1884 close(c->sock); 1885 c->sock = c->rfd = c->wfd = sock; 1886 channel_find_maxfd(ssh->chanctxt); 1887 return; 1888 } 1889 /* Exhausted all addresses */ 1890 error("connect_to %.100s port %d: failed.", 1891 c->connect_ctx.host, c->connect_ctx.port); 1892 channel_connect_ctx_free(&c->connect_ctx); 1893 if (isopen) { 1894 rdynamic_close(ssh, c); 1895 } else { 1896 if ((r = sshpkt_start(ssh, 1897 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1898 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1899 (r = sshpkt_put_u32(ssh, 1900 SSH2_OPEN_CONNECT_FAILED)) != 0 || 1901 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 1902 (r = sshpkt_put_cstring(ssh, "")) != 0) { 1903 fatal("%s: channel %i: failure: %s", __func__, 1904 c->self, ssh_err(r)); 1905 } 1906 if ((r = sshpkt_send(ssh)) != 0) 1907 fatal("%s: channel %i: %s", __func__, c->self, 1908 ssh_err(r)); 1909 chan_mark_dead(ssh, c); 1910 } 1911 } 1912 } 1913 1914 static int 1915 channel_handle_rfd(struct ssh *ssh, Channel *c, 1916 fd_set *readset, fd_set *writeset) 1917 { 1918 char buf[CHAN_RBUF]; 1919 ssize_t len; 1920 int r; 1921 1922 if (c->rfd == -1 || !FD_ISSET(c->rfd, readset)) 1923 return 1; 1924 1925 len = read(c->rfd, buf, sizeof(buf)); 1926 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1927 return 1; 1928 if (len <= 0) { 1929 debug2("channel %d: read<=0 rfd %d len %zd", 1930 c->self, c->rfd, len); 1931 if (c->type != SSH_CHANNEL_OPEN) { 1932 debug2("channel %d: not open", c->self); 1933 chan_mark_dead(ssh, c); 1934 return -1; 1935 } else { 1936 chan_read_failed(ssh, c); 1937 } 1938 return -1; 1939 } 1940 if (c->input_filter != NULL) { 1941 if (c->input_filter(ssh, c, buf, len) == -1) { 1942 debug2("channel %d: filter stops", c->self); 1943 chan_read_failed(ssh, c); 1944 } 1945 } else if (c->datagram) { 1946 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 1947 fatal("%s: channel %d: put datagram: %s", __func__, 1948 c->self, ssh_err(r)); 1949 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { 1950 fatal("%s: channel %d: put data: %s", __func__, 1951 c->self, ssh_err(r)); 1952 } 1953 return 1; 1954 } 1955 1956 static int 1957 channel_handle_wfd(struct ssh *ssh, Channel *c, 1958 fd_set *readset, fd_set *writeset) 1959 { 1960 struct termios tio; 1961 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 1962 size_t dlen, olen = 0; 1963 int r, len; 1964 1965 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || 1966 sshbuf_len(c->output) == 0) 1967 return 1; 1968 1969 /* Send buffered output data to the socket. */ 1970 olen = sshbuf_len(c->output); 1971 if (c->output_filter != NULL) { 1972 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 1973 debug2("channel %d: filter stops", c->self); 1974 if (c->type != SSH_CHANNEL_OPEN) 1975 chan_mark_dead(ssh, c); 1976 else 1977 chan_write_failed(ssh, c); 1978 return -1; 1979 } 1980 } else if (c->datagram) { 1981 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 1982 fatal("%s: channel %d: get datagram: %s", __func__, 1983 c->self, ssh_err(r)); 1984 buf = data; 1985 } else { 1986 buf = data = sshbuf_mutable_ptr(c->output); 1987 dlen = sshbuf_len(c->output); 1988 } 1989 1990 if (c->datagram) { 1991 /* ignore truncated writes, datagrams might get lost */ 1992 len = write(c->wfd, buf, dlen); 1993 free(data); 1994 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1995 return 1; 1996 if (len <= 0) 1997 goto write_fail; 1998 goto out; 1999 } 2000 2001 len = write(c->wfd, buf, dlen); 2002 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 2003 return 1; 2004 if (len <= 0) { 2005 write_fail: 2006 if (c->type != SSH_CHANNEL_OPEN) { 2007 debug2("channel %d: not open", c->self); 2008 chan_mark_dead(ssh, c); 2009 return -1; 2010 } else { 2011 chan_write_failed(ssh, c); 2012 } 2013 return -1; 2014 } 2015 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2016 if (tcgetattr(c->wfd, &tio) == 0 && 2017 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2018 /* 2019 * Simulate echo to reduce the impact of 2020 * traffic analysis. We need to match the 2021 * size of a SSH2_MSG_CHANNEL_DATA message 2022 * (4 byte channel id + buf) 2023 */ 2024 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2025 (r = sshpkt_send(ssh)) != 0) 2026 fatal("%s: channel %d: ignore: %s", 2027 __func__, c->self, ssh_err(r)); 2028 } 2029 } 2030 if ((r = sshbuf_consume(c->output, len)) != 0) { 2031 fatal("%s: channel %d: consume: %s", 2032 __func__, c->self, ssh_err(r)); 2033 } 2034 out: 2035 c->local_consumed += olen - sshbuf_len(c->output); 2036 2037 return 1; 2038 } 2039 2040 static int 2041 channel_handle_efd_write(struct ssh *ssh, Channel *c, 2042 fd_set *readset, fd_set *writeset) 2043 { 2044 int r; 2045 ssize_t len; 2046 2047 if (!FD_ISSET(c->efd, writeset) || sshbuf_len(c->extended) == 0) 2048 return 1; 2049 2050 len = write(c->efd, sshbuf_ptr(c->extended), 2051 sshbuf_len(c->extended)); 2052 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2053 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 2054 return 1; 2055 if (len <= 0) { 2056 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2057 channel_close_fd(ssh, &c->efd); 2058 } else { 2059 if ((r = sshbuf_consume(c->extended, len)) != 0) { 2060 fatal("%s: channel %d: consume: %s", 2061 __func__, c->self, ssh_err(r)); 2062 } 2063 c->local_consumed += len; 2064 } 2065 return 1; 2066 } 2067 2068 static int 2069 channel_handle_efd_read(struct ssh *ssh, Channel *c, 2070 fd_set *readset, fd_set *writeset) 2071 { 2072 char buf[CHAN_RBUF]; 2073 int r; 2074 ssize_t len; 2075 2076 if (!FD_ISSET(c->efd, readset)) 2077 return 1; 2078 2079 len = read(c->efd, buf, sizeof(buf)); 2080 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2081 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 2082 return 1; 2083 if (len <= 0) { 2084 debug2("channel %d: closing read-efd %d", 2085 c->self, c->efd); 2086 channel_close_fd(ssh, &c->efd); 2087 } else { 2088 if (c->extended_usage == CHAN_EXTENDED_IGNORE) { 2089 debug3("channel %d: discard efd", 2090 c->self); 2091 } else if ((r = sshbuf_put(c->extended, buf, len)) != 0) { 2092 fatal("%s: channel %d: append: %s", 2093 __func__, c->self, ssh_err(r)); 2094 } 2095 } 2096 return 1; 2097 } 2098 2099 static int 2100 channel_handle_efd(struct ssh *ssh, Channel *c, 2101 fd_set *readset, fd_set *writeset) 2102 { 2103 if (c->efd == -1) 2104 return 1; 2105 2106 /** XXX handle drain efd, too */ 2107 2108 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2109 return channel_handle_efd_write(ssh, c, readset, writeset); 2110 else if (c->extended_usage == CHAN_EXTENDED_READ || 2111 c->extended_usage == CHAN_EXTENDED_IGNORE) 2112 return channel_handle_efd_read(ssh, c, readset, writeset); 2113 2114 return 1; 2115 } 2116 2117 static int 2118 channel_check_window(struct ssh *ssh, Channel *c) 2119 { 2120 int r; 2121 2122 if (c->type == SSH_CHANNEL_OPEN && 2123 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2124 ((c->local_window_max - c->local_window > 2125 c->local_maxpacket*3) || 2126 c->local_window < c->local_window_max/2) && 2127 c->local_consumed > 0) { 2128 if (!c->have_remote_id) 2129 fatal(":%s: channel %d: no remote id", 2130 __func__, c->self); 2131 if ((r = sshpkt_start(ssh, 2132 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2133 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2134 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2135 (r = sshpkt_send(ssh)) != 0) { 2136 fatal("%s: channel %i: %s", __func__, 2137 c->self, ssh_err(r)); 2138 } 2139 debug2("channel %d: window %d sent adjust %d", 2140 c->self, c->local_window, 2141 c->local_consumed); 2142 c->local_window += c->local_consumed; 2143 c->local_consumed = 0; 2144 } 2145 return 1; 2146 } 2147 2148 static void 2149 channel_post_open(struct ssh *ssh, Channel *c, 2150 fd_set *readset, fd_set *writeset) 2151 { 2152 channel_handle_rfd(ssh, c, readset, writeset); 2153 channel_handle_wfd(ssh, c, readset, writeset); 2154 channel_handle_efd(ssh, c, readset, writeset); 2155 channel_check_window(ssh, c); 2156 } 2157 2158 static u_int 2159 read_mux(struct ssh *ssh, Channel *c, u_int need) 2160 { 2161 char buf[CHAN_RBUF]; 2162 ssize_t len; 2163 u_int rlen; 2164 int r; 2165 2166 if (sshbuf_len(c->input) < need) { 2167 rlen = need - sshbuf_len(c->input); 2168 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2169 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 2170 return sshbuf_len(c->input); 2171 if (len <= 0) { 2172 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2173 c->self, c->rfd, len); 2174 chan_read_failed(ssh, c); 2175 return 0; 2176 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { 2177 fatal("%s: channel %d: append: %s", 2178 __func__, c->self, ssh_err(r)); 2179 } 2180 } 2181 return sshbuf_len(c->input); 2182 } 2183 2184 static void 2185 channel_post_mux_client_read(struct ssh *ssh, Channel *c, 2186 fd_set *readset, fd_set *writeset) 2187 { 2188 u_int need; 2189 2190 if (c->rfd == -1 || !FD_ISSET(c->rfd, readset)) 2191 return; 2192 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2193 return; 2194 if (c->mux_pause) 2195 return; 2196 2197 /* 2198 * Don't not read past the precise end of packets to 2199 * avoid disrupting fd passing. 2200 */ 2201 if (read_mux(ssh, c, 4) < 4) /* read header */ 2202 return; 2203 /* XXX sshbuf_peek_u32 */ 2204 need = PEEK_U32(sshbuf_ptr(c->input)); 2205 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2206 if (need > CHANNEL_MUX_MAX_PACKET) { 2207 debug2("channel %d: packet too big %u > %u", 2208 c->self, CHANNEL_MUX_MAX_PACKET, need); 2209 chan_rcvd_oclose(ssh, c); 2210 return; 2211 } 2212 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2213 return; 2214 if (c->mux_rcb(ssh, c) != 0) { 2215 debug("channel %d: mux_rcb failed", c->self); 2216 chan_mark_dead(ssh, c); 2217 return; 2218 } 2219 } 2220 2221 static void 2222 channel_post_mux_client_write(struct ssh *ssh, Channel *c, 2223 fd_set *readset, fd_set *writeset) 2224 { 2225 ssize_t len; 2226 int r; 2227 2228 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || 2229 sshbuf_len(c->output) == 0) 2230 return; 2231 2232 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2233 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 2234 return; 2235 if (len <= 0) { 2236 chan_mark_dead(ssh, c); 2237 return; 2238 } 2239 if ((r = sshbuf_consume(c->output, len)) != 0) 2240 fatal("%s: channel %d: consume: %s", __func__, 2241 c->self, ssh_err(r)); 2242 } 2243 2244 static void 2245 channel_post_mux_client(struct ssh *ssh, Channel *c, 2246 fd_set *readset, fd_set *writeset) 2247 { 2248 channel_post_mux_client_read(ssh, c, readset, writeset); 2249 channel_post_mux_client_write(ssh, c, readset, writeset); 2250 } 2251 2252 static void 2253 channel_post_mux_listener(struct ssh *ssh, Channel *c, 2254 fd_set *readset, fd_set *writeset) 2255 { 2256 Channel *nc; 2257 struct sockaddr_storage addr; 2258 socklen_t addrlen; 2259 int newsock; 2260 uid_t euid; 2261 gid_t egid; 2262 2263 if (!FD_ISSET(c->sock, readset)) 2264 return; 2265 2266 debug("multiplexing control connection"); 2267 2268 /* 2269 * Accept connection on control socket 2270 */ 2271 memset(&addr, 0, sizeof(addr)); 2272 addrlen = sizeof(addr); 2273 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2274 &addrlen)) == -1) { 2275 error("%s accept: %s", __func__, strerror(errno)); 2276 if (errno == EMFILE || errno == ENFILE) 2277 c->notbefore = monotime() + 1; 2278 return; 2279 } 2280 2281 if (getpeereid(newsock, &euid, &egid) < 0) { 2282 error("%s getpeereid failed: %s", __func__, 2283 strerror(errno)); 2284 close(newsock); 2285 return; 2286 } 2287 if ((euid != 0) && (getuid() != euid)) { 2288 error("multiplex uid mismatch: peer euid %u != uid %u", 2289 (u_int)euid, (u_int)getuid()); 2290 close(newsock); 2291 return; 2292 } 2293 nc = channel_new(ssh, "multiplex client", SSH_CHANNEL_MUX_CLIENT, 2294 newsock, newsock, -1, c->local_window_max, 2295 c->local_maxpacket, 0, "mux-control", 1); 2296 nc->mux_rcb = c->mux_rcb; 2297 debug3("%s: new mux channel %d fd %d", __func__, nc->self, nc->sock); 2298 /* establish state */ 2299 nc->mux_rcb(ssh, nc); 2300 /* mux state transitions must not elicit protocol messages */ 2301 nc->flags |= CHAN_LOCAL; 2302 } 2303 2304 static void 2305 channel_handler_init(struct ssh_channels *sc) 2306 { 2307 chan_fn **pre, **post; 2308 2309 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2310 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2311 fatal("%s: allocation failed", __func__); 2312 2313 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2314 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2315 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2316 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2317 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2318 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2319 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2320 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2321 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2322 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2323 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2324 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2325 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2326 2327 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2328 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2329 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2330 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2331 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2332 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2333 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2334 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2335 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2336 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2337 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2338 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2339 2340 sc->channel_pre = pre; 2341 sc->channel_post = post; 2342 } 2343 2344 /* gc dead channels */ 2345 static void 2346 channel_garbage_collect(struct ssh *ssh, Channel *c) 2347 { 2348 if (c == NULL) 2349 return; 2350 if (c->detach_user != NULL) { 2351 if (!chan_is_dead(ssh, c, c->detach_close)) 2352 return; 2353 2354 debug2("channel %d: gc: notify user", c->self); 2355 c->detach_user(ssh, c->self, NULL); 2356 /* if we still have a callback */ 2357 if (c->detach_user != NULL) 2358 return; 2359 debug2("channel %d: gc: user detached", c->self); 2360 } 2361 if (!chan_is_dead(ssh, c, 1)) 2362 return; 2363 debug2("channel %d: garbage collecting", c->self); 2364 channel_free(ssh, c); 2365 } 2366 2367 enum channel_table { CHAN_PRE, CHAN_POST }; 2368 2369 static void 2370 channel_handler(struct ssh *ssh, int table, 2371 fd_set *readset, fd_set *writeset, time_t *unpause_secs) 2372 { 2373 struct ssh_channels *sc = ssh->chanctxt; 2374 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2375 u_int i, oalloc; 2376 Channel *c; 2377 time_t now; 2378 2379 now = monotime(); 2380 if (unpause_secs != NULL) 2381 *unpause_secs = 0; 2382 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2383 c = sc->channels[i]; 2384 if (c == NULL) 2385 continue; 2386 if (c->delayed) { 2387 if (table == CHAN_PRE) 2388 c->delayed = 0; 2389 else 2390 continue; 2391 } 2392 if (ftab[c->type] != NULL) { 2393 /* 2394 * Run handlers that are not paused. 2395 */ 2396 if (c->notbefore <= now) 2397 (*ftab[c->type])(ssh, c, readset, writeset); 2398 else if (unpause_secs != NULL) { 2399 /* 2400 * Collect the time that the earliest 2401 * channel comes off pause. 2402 */ 2403 debug3("%s: chan %d: skip for %d more seconds", 2404 __func__, c->self, 2405 (int)(c->notbefore - now)); 2406 if (*unpause_secs == 0 || 2407 (c->notbefore - now) < *unpause_secs) 2408 *unpause_secs = c->notbefore - now; 2409 } 2410 } 2411 channel_garbage_collect(ssh, c); 2412 } 2413 if (unpause_secs != NULL && *unpause_secs != 0) 2414 debug3("%s: first channel unpauses in %d seconds", 2415 __func__, (int)*unpause_secs); 2416 } 2417 2418 /* 2419 * Create sockets before allocating the select bitmasks. 2420 * This is necessary for things that need to happen after reading 2421 * the network-input but before channel_prepare_select(). 2422 */ 2423 static void 2424 channel_before_prepare_select(struct ssh *ssh) 2425 { 2426 struct ssh_channels *sc = ssh->chanctxt; 2427 Channel *c; 2428 u_int i, oalloc; 2429 2430 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2431 c = sc->channels[i]; 2432 if (c == NULL) 2433 continue; 2434 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2435 channel_before_prepare_select_rdynamic(ssh, c); 2436 } 2437 } 2438 2439 /* 2440 * Allocate/update select bitmasks and add any bits relevant to channels in 2441 * select bitmasks. 2442 */ 2443 void 2444 channel_prepare_select(struct ssh *ssh, fd_set **readsetp, fd_set **writesetp, 2445 int *maxfdp, u_int *nallocp, time_t *minwait_secs) 2446 { 2447 u_int n, sz, nfdset; 2448 2449 channel_before_prepare_select(ssh); /* might update channel_max_fd */ 2450 2451 n = MAXIMUM(*maxfdp, ssh->chanctxt->channel_max_fd); 2452 2453 nfdset = howmany(n+1, NFDBITS); 2454 /* Explicitly test here, because xrealloc isn't always called */ 2455 if (nfdset && SIZE_MAX / nfdset < sizeof(fd_mask)) 2456 fatal("channel_prepare_select: max_fd (%d) is too large", n); 2457 sz = nfdset * sizeof(fd_mask); 2458 2459 /* perhaps check sz < nalloc/2 and shrink? */ 2460 if (*readsetp == NULL || sz > *nallocp) { 2461 *readsetp = xreallocarray(*readsetp, nfdset, sizeof(fd_mask)); 2462 *writesetp = xreallocarray(*writesetp, nfdset, sizeof(fd_mask)); 2463 *nallocp = sz; 2464 } 2465 *maxfdp = n; 2466 memset(*readsetp, 0, sz); 2467 memset(*writesetp, 0, sz); 2468 2469 if (!ssh_packet_is_rekeying(ssh)) 2470 channel_handler(ssh, CHAN_PRE, *readsetp, *writesetp, 2471 minwait_secs); 2472 } 2473 2474 /* 2475 * After select, perform any appropriate operations for channels which have 2476 * events pending. 2477 */ 2478 void 2479 channel_after_select(struct ssh *ssh, fd_set *readset, fd_set *writeset) 2480 { 2481 channel_handler(ssh, CHAN_POST, readset, writeset, NULL); 2482 } 2483 2484 /* 2485 * Enqueue data for channels with open or draining c->input. 2486 */ 2487 static void 2488 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2489 { 2490 size_t len, plen; 2491 const u_char *pkt; 2492 int r; 2493 2494 if ((len = sshbuf_len(c->input)) == 0) { 2495 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2496 /* 2497 * input-buffer is empty and read-socket shutdown: 2498 * tell peer, that we will not send more data: 2499 * send IEOF. 2500 * hack for extended data: delay EOF if EFD still 2501 * in use. 2502 */ 2503 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2504 debug2("channel %d: " 2505 "ibuf_empty delayed efd %d/(%zu)", 2506 c->self, c->efd, sshbuf_len(c->extended)); 2507 else 2508 chan_ibuf_empty(ssh, c); 2509 } 2510 return; 2511 } 2512 2513 if (!c->have_remote_id) 2514 fatal(":%s: channel %d: no remote id", __func__, c->self); 2515 2516 if (c->datagram) { 2517 /* Check datagram will fit; drop if not */ 2518 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2519 fatal("%s: channel %d: get datagram: %s", __func__, 2520 c->self, ssh_err(r)); 2521 /* 2522 * XXX this does tail-drop on the datagram queue which is 2523 * usually suboptimal compared to head-drop. Better to have 2524 * backpressure at read time? (i.e. read + discard) 2525 */ 2526 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2527 debug("channel %d: datagram too big", c->self); 2528 return; 2529 } 2530 /* Enqueue it */ 2531 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2532 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2533 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2534 (r = sshpkt_send(ssh)) != 0) { 2535 fatal("%s: channel %i: datagram: %s", __func__, 2536 c->self, ssh_err(r)); 2537 } 2538 c->remote_window -= plen; 2539 return; 2540 } 2541 2542 /* Enqueue packet for buffered data. */ 2543 if (len > c->remote_window) 2544 len = c->remote_window; 2545 if (len > c->remote_maxpacket) 2546 len = c->remote_maxpacket; 2547 if (len == 0) 2548 return; 2549 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2550 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2551 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2552 (r = sshpkt_send(ssh)) != 0) { 2553 fatal("%s: channel %i: data: %s", __func__, 2554 c->self, ssh_err(r)); 2555 } 2556 if ((r = sshbuf_consume(c->input, len)) != 0) 2557 fatal("%s: channel %i: consume: %s", __func__, 2558 c->self, ssh_err(r)); 2559 c->remote_window -= len; 2560 } 2561 2562 /* 2563 * Enqueue data for channels with open c->extended in read mode. 2564 */ 2565 static void 2566 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2567 { 2568 size_t len; 2569 int r; 2570 2571 if ((len = sshbuf_len(c->extended)) == 0) 2572 return; 2573 2574 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2575 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2576 if (len > c->remote_window) 2577 len = c->remote_window; 2578 if (len > c->remote_maxpacket) 2579 len = c->remote_maxpacket; 2580 if (len == 0) 2581 return; 2582 if (!c->have_remote_id) 2583 fatal(":%s: channel %d: no remote id", __func__, c->self); 2584 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2585 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2586 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2587 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2588 (r = sshpkt_send(ssh)) != 0) { 2589 fatal("%s: channel %i: data: %s", __func__, 2590 c->self, ssh_err(r)); 2591 } 2592 if ((r = sshbuf_consume(c->extended, len)) != 0) 2593 fatal("%s: channel %i: consume: %s", __func__, 2594 c->self, ssh_err(r)); 2595 c->remote_window -= len; 2596 debug2("channel %d: sent ext data %zu", c->self, len); 2597 } 2598 2599 /* If there is data to send to the connection, enqueue some of it now. */ 2600 void 2601 channel_output_poll(struct ssh *ssh) 2602 { 2603 struct ssh_channels *sc = ssh->chanctxt; 2604 Channel *c; 2605 u_int i; 2606 2607 for (i = 0; i < sc->channels_alloc; i++) { 2608 c = sc->channels[i]; 2609 if (c == NULL) 2610 continue; 2611 2612 /* 2613 * We are only interested in channels that can have buffered 2614 * incoming data. 2615 */ 2616 if (c->type != SSH_CHANNEL_OPEN) 2617 continue; 2618 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2619 /* XXX is this true? */ 2620 debug3("channel %d: will not send data after close", 2621 c->self); 2622 continue; 2623 } 2624 2625 /* Get the amount of buffered data for this channel. */ 2626 if (c->istate == CHAN_INPUT_OPEN || 2627 c->istate == CHAN_INPUT_WAIT_DRAIN) 2628 channel_output_poll_input_open(ssh, c); 2629 /* Send extended data, i.e. stderr */ 2630 if (!(c->flags & CHAN_EOF_SENT) && 2631 c->extended_usage == CHAN_EXTENDED_READ) 2632 channel_output_poll_extended_read(ssh, c); 2633 } 2634 } 2635 2636 /* -- mux proxy support */ 2637 2638 /* 2639 * When multiplexing channel messages for mux clients we have to deal 2640 * with downstream messages from the mux client and upstream messages 2641 * from the ssh server: 2642 * 1) Handling downstream messages is straightforward and happens 2643 * in channel_proxy_downstream(): 2644 * - We forward all messages (mostly) unmodified to the server. 2645 * - However, in order to route messages from upstream to the correct 2646 * downstream client, we have to replace the channel IDs used by the 2647 * mux clients with a unique channel ID because the mux clients might 2648 * use conflicting channel IDs. 2649 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 2650 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 2651 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 2652 * with the newly allocated channel ID. 2653 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 2654 * channels and processed by channel_proxy_upstream(). The local channel ID 2655 * is then translated back to the original mux client ID. 2656 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 2657 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 2658 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 2659 * downstream mux client are removed. 2660 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 2661 * requires more work, because they are not addressed to a specific 2662 * channel. E.g. client_request_forwarded_tcpip() needs to figure 2663 * out whether the request is addressed to the local client or a 2664 * specific downstream client based on the listen-address/port. 2665 * 6) Agent and X11-Forwarding have a similar problem and are currently 2666 * not supported as the matching session/channel cannot be identified 2667 * easily. 2668 */ 2669 2670 /* 2671 * receive packets from downstream mux clients: 2672 * channel callback fired on read from mux client, creates 2673 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 2674 * on channel creation. 2675 */ 2676 int 2677 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 2678 { 2679 Channel *c = NULL; 2680 struct sshbuf *original = NULL, *modified = NULL; 2681 const u_char *cp; 2682 char *ctype = NULL, *listen_host = NULL; 2683 u_char type; 2684 size_t have; 2685 int ret = -1, r; 2686 u_int id, remote_id, listen_port; 2687 2688 /* sshbuf_dump(downstream->input, stderr); */ 2689 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 2690 != 0) { 2691 error("%s: malformed message: %s", __func__, ssh_err(r)); 2692 return -1; 2693 } 2694 if (have < 2) { 2695 error("%s: short message", __func__); 2696 return -1; 2697 } 2698 type = cp[1]; 2699 /* skip padlen + type */ 2700 cp += 2; 2701 have -= 2; 2702 if (ssh_packet_log_type(type)) 2703 debug3("%s: channel %u: down->up: type %u", __func__, 2704 downstream->self, type); 2705 2706 switch (type) { 2707 case SSH2_MSG_CHANNEL_OPEN: 2708 if ((original = sshbuf_from(cp, have)) == NULL || 2709 (modified = sshbuf_new()) == NULL) { 2710 error("%s: alloc", __func__); 2711 goto out; 2712 } 2713 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 2714 (r = sshbuf_get_u32(original, &id)) != 0) { 2715 error("%s: parse error %s", __func__, ssh_err(r)); 2716 goto out; 2717 } 2718 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2719 -1, -1, -1, 0, 0, 0, ctype, 1); 2720 c->mux_ctx = downstream; /* point to mux client */ 2721 c->mux_downstream_id = id; /* original downstream id */ 2722 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 2723 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2724 (r = sshbuf_putb(modified, original)) != 0) { 2725 error("%s: compose error %s", __func__, ssh_err(r)); 2726 channel_free(ssh, c); 2727 goto out; 2728 } 2729 break; 2730 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2731 /* 2732 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 2733 * need to parse 'remote_id' instead of 'ctype'. 2734 */ 2735 if ((original = sshbuf_from(cp, have)) == NULL || 2736 (modified = sshbuf_new()) == NULL) { 2737 error("%s: alloc", __func__); 2738 goto out; 2739 } 2740 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 2741 (r = sshbuf_get_u32(original, &id)) != 0) { 2742 error("%s: parse error %s", __func__, ssh_err(r)); 2743 goto out; 2744 } 2745 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2746 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 2747 c->mux_ctx = downstream; /* point to mux client */ 2748 c->mux_downstream_id = id; 2749 c->remote_id = remote_id; 2750 c->have_remote_id = 1; 2751 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 2752 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2753 (r = sshbuf_putb(modified, original)) != 0) { 2754 error("%s: compose error %s", __func__, ssh_err(r)); 2755 channel_free(ssh, c); 2756 goto out; 2757 } 2758 break; 2759 case SSH2_MSG_GLOBAL_REQUEST: 2760 if ((original = sshbuf_from(cp, have)) == NULL) { 2761 error("%s: alloc", __func__); 2762 goto out; 2763 } 2764 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 2765 error("%s: parse error %s", __func__, ssh_err(r)); 2766 goto out; 2767 } 2768 if (strcmp(ctype, "tcpip-forward") != 0) { 2769 error("%s: unsupported request %s", __func__, ctype); 2770 goto out; 2771 } 2772 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 2773 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 2774 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 2775 error("%s: parse error %s", __func__, ssh_err(r)); 2776 goto out; 2777 } 2778 if (listen_port > 65535) { 2779 error("%s: tcpip-forward for %s: bad port %u", 2780 __func__, listen_host, listen_port); 2781 goto out; 2782 } 2783 /* Record that connection to this host/port is permitted. */ 2784 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 2785 listen_host, NULL, (int)listen_port, downstream); 2786 listen_host = NULL; 2787 break; 2788 case SSH2_MSG_CHANNEL_CLOSE: 2789 if (have < 4) 2790 break; 2791 remote_id = PEEK_U32(cp); 2792 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 2793 if (c->flags & CHAN_CLOSE_RCVD) 2794 channel_free(ssh, c); 2795 else 2796 c->flags |= CHAN_CLOSE_SENT; 2797 } 2798 break; 2799 } 2800 if (modified) { 2801 if ((r = sshpkt_start(ssh, type)) != 0 || 2802 (r = sshpkt_putb(ssh, modified)) != 0 || 2803 (r = sshpkt_send(ssh)) != 0) { 2804 error("%s: send %s", __func__, ssh_err(r)); 2805 goto out; 2806 } 2807 } else { 2808 if ((r = sshpkt_start(ssh, type)) != 0 || 2809 (r = sshpkt_put(ssh, cp, have)) != 0 || 2810 (r = sshpkt_send(ssh)) != 0) { 2811 error("%s: send %s", __func__, ssh_err(r)); 2812 goto out; 2813 } 2814 } 2815 ret = 0; 2816 out: 2817 free(ctype); 2818 free(listen_host); 2819 sshbuf_free(original); 2820 sshbuf_free(modified); 2821 return ret; 2822 } 2823 2824 /* 2825 * receive packets from upstream server and de-multiplex packets 2826 * to correct downstream: 2827 * implemented as a helper for channel input handlers, 2828 * replaces local (proxy) channel ID with downstream channel ID. 2829 */ 2830 int 2831 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 2832 { 2833 struct sshbuf *b = NULL; 2834 Channel *downstream; 2835 const u_char *cp = NULL; 2836 size_t len; 2837 int r; 2838 2839 /* 2840 * When receiving packets from the peer we need to check whether we 2841 * need to forward the packets to the mux client. In this case we 2842 * restore the original channel id and keep track of CLOSE messages, 2843 * so we can cleanup the channel. 2844 */ 2845 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 2846 return 0; 2847 if ((downstream = c->mux_ctx) == NULL) 2848 return 0; 2849 switch (type) { 2850 case SSH2_MSG_CHANNEL_CLOSE: 2851 case SSH2_MSG_CHANNEL_DATA: 2852 case SSH2_MSG_CHANNEL_EOF: 2853 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 2854 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2855 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 2856 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 2857 case SSH2_MSG_CHANNEL_SUCCESS: 2858 case SSH2_MSG_CHANNEL_FAILURE: 2859 case SSH2_MSG_CHANNEL_REQUEST: 2860 break; 2861 default: 2862 debug2("%s: channel %u: unsupported type %u", __func__, 2863 c->self, type); 2864 return 0; 2865 } 2866 if ((b = sshbuf_new()) == NULL) { 2867 error("%s: alloc reply", __func__); 2868 goto out; 2869 } 2870 /* get remaining payload (after id) */ 2871 cp = sshpkt_ptr(ssh, &len); 2872 if (cp == NULL) { 2873 error("%s: no packet", __func__); 2874 goto out; 2875 } 2876 /* translate id and send to muxclient */ 2877 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 2878 (r = sshbuf_put_u8(b, type)) != 0 || 2879 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 2880 (r = sshbuf_put(b, cp, len)) != 0 || 2881 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 2882 error("%s: compose for muxclient %s", __func__, ssh_err(r)); 2883 goto out; 2884 } 2885 /* sshbuf_dump(b, stderr); */ 2886 if (ssh_packet_log_type(type)) 2887 debug3("%s: channel %u: up->down: type %u", __func__, c->self, 2888 type); 2889 out: 2890 /* update state */ 2891 switch (type) { 2892 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2893 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 2894 if (cp && len > 4) { 2895 c->remote_id = PEEK_U32(cp); 2896 c->have_remote_id = 1; 2897 } 2898 break; 2899 case SSH2_MSG_CHANNEL_CLOSE: 2900 if (c->flags & CHAN_CLOSE_SENT) 2901 channel_free(ssh, c); 2902 else 2903 c->flags |= CHAN_CLOSE_RCVD; 2904 break; 2905 } 2906 sshbuf_free(b); 2907 return 1; 2908 } 2909 2910 /* -- protocol input */ 2911 2912 /* Parse a channel ID from the current packet */ 2913 static int 2914 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 2915 { 2916 u_int32_t id; 2917 int r; 2918 2919 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 2920 error("%s: parse id: %s", where, ssh_err(r)); 2921 ssh_packet_disconnect(ssh, "Invalid %s message", what); 2922 } 2923 if (id > INT_MAX) { 2924 error("%s: bad channel id %u: %s", where, id, ssh_err(r)); 2925 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 2926 } 2927 return (int)id; 2928 } 2929 2930 /* Lookup a channel from an ID in the current packet */ 2931 static Channel * 2932 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 2933 { 2934 int id = channel_parse_id(ssh, where, what); 2935 Channel *c; 2936 2937 if ((c = channel_lookup(ssh, id)) == NULL) { 2938 ssh_packet_disconnect(ssh, 2939 "%s packet referred to nonexistent channel %d", what, id); 2940 } 2941 return c; 2942 } 2943 2944 int 2945 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 2946 { 2947 const u_char *data; 2948 size_t data_len, win_len; 2949 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 2950 int r; 2951 2952 if (channel_proxy_upstream(c, type, seq, ssh)) 2953 return 0; 2954 2955 /* Ignore any data for non-open channels (might happen on close) */ 2956 if (c->type != SSH_CHANNEL_OPEN && 2957 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 2958 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 2959 c->type != SSH_CHANNEL_X11_OPEN) 2960 return 0; 2961 2962 /* Get the data. */ 2963 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0) 2964 fatal("%s: channel %d: get data: %s", __func__, 2965 c->self, ssh_err(r)); 2966 ssh_packet_check_eom(ssh); 2967 2968 win_len = data_len; 2969 if (c->datagram) 2970 win_len += 4; /* string length header */ 2971 2972 /* 2973 * The sending side reduces its window as it sends data, so we 2974 * must 'fake' consumption of the data in order to ensure that window 2975 * updates are sent back. Otherwise the connection might deadlock. 2976 */ 2977 if (c->ostate != CHAN_OUTPUT_OPEN) { 2978 c->local_window -= win_len; 2979 c->local_consumed += win_len; 2980 return 0; 2981 } 2982 2983 if (win_len > c->local_maxpacket) { 2984 logit("channel %d: rcvd big packet %zu, maxpack %u", 2985 c->self, win_len, c->local_maxpacket); 2986 return 0; 2987 } 2988 if (win_len > c->local_window) { 2989 logit("channel %d: rcvd too much data %zu, win %u", 2990 c->self, win_len, c->local_window); 2991 return 0; 2992 } 2993 c->local_window -= win_len; 2994 2995 if (c->datagram) { 2996 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 2997 fatal("%s: channel %d: append datagram: %s", 2998 __func__, c->self, ssh_err(r)); 2999 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3000 fatal("%s: channel %d: append data: %s", 3001 __func__, c->self, ssh_err(r)); 3002 3003 return 0; 3004 } 3005 3006 int 3007 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3008 { 3009 const u_char *data; 3010 size_t data_len; 3011 u_int32_t tcode; 3012 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3013 int r; 3014 3015 if (channel_proxy_upstream(c, type, seq, ssh)) 3016 return 0; 3017 if (c->type != SSH_CHANNEL_OPEN) { 3018 logit("channel %d: ext data for non open", c->self); 3019 return 0; 3020 } 3021 if (c->flags & CHAN_EOF_RCVD) { 3022 if (datafellows & SSH_BUG_EXTEOF) 3023 debug("channel %d: accepting ext data after eof", 3024 c->self); 3025 else 3026 ssh_packet_disconnect(ssh, "Received extended_data " 3027 "after EOF on channel %d.", c->self); 3028 } 3029 3030 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3031 error("%s: parse tcode: %s", __func__, ssh_err(r)); 3032 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3033 } 3034 if (c->efd == -1 || 3035 c->extended_usage != CHAN_EXTENDED_WRITE || 3036 tcode != SSH2_EXTENDED_DATA_STDERR) { 3037 logit("channel %d: bad ext data", c->self); 3038 return 0; 3039 } 3040 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0) { 3041 error("%s: parse data: %s", __func__, ssh_err(r)); 3042 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3043 } 3044 ssh_packet_check_eom(ssh); 3045 3046 if (data_len > c->local_window) { 3047 logit("channel %d: rcvd too much extended_data %zu, win %u", 3048 c->self, data_len, c->local_window); 3049 return 0; 3050 } 3051 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3052 /* XXX sshpkt_getb? */ 3053 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3054 error("%s: append: %s", __func__, ssh_err(r)); 3055 c->local_window -= data_len; 3056 return 0; 3057 } 3058 3059 int 3060 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3061 { 3062 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3063 3064 ssh_packet_check_eom(ssh); 3065 3066 if (channel_proxy_upstream(c, type, seq, ssh)) 3067 return 0; 3068 chan_rcvd_ieof(ssh, c); 3069 3070 /* XXX force input close */ 3071 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3072 debug("channel %d: FORCE input drain", c->self); 3073 c->istate = CHAN_INPUT_WAIT_DRAIN; 3074 if (sshbuf_len(c->input) == 0) 3075 chan_ibuf_empty(ssh, c); 3076 } 3077 return 0; 3078 } 3079 3080 int 3081 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3082 { 3083 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3084 3085 if (channel_proxy_upstream(c, type, seq, ssh)) 3086 return 0; 3087 ssh_packet_check_eom(ssh); 3088 chan_rcvd_oclose(ssh, c); 3089 return 0; 3090 } 3091 3092 int 3093 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3094 { 3095 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3096 u_int32_t remote_window, remote_maxpacket; 3097 int r; 3098 3099 if (channel_proxy_upstream(c, type, seq, ssh)) 3100 return 0; 3101 if (c->type != SSH_CHANNEL_OPENING) 3102 packet_disconnect("Received open confirmation for " 3103 "non-opening channel %d.", c->self); 3104 /* 3105 * Record the remote channel number and mark that the channel 3106 * is now open. 3107 */ 3108 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3109 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3110 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0) { 3111 error("%s: window/maxpacket: %s", __func__, ssh_err(r)); 3112 packet_disconnect("Invalid open confirmation message"); 3113 } 3114 ssh_packet_check_eom(ssh); 3115 3116 c->have_remote_id = 1; 3117 c->remote_window = remote_window; 3118 c->remote_maxpacket = remote_maxpacket; 3119 c->type = SSH_CHANNEL_OPEN; 3120 if (c->open_confirm) { 3121 debug2("%s: channel %d: callback start", __func__, c->self); 3122 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3123 debug2("%s: channel %d: callback done", __func__, c->self); 3124 } 3125 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3126 c->remote_window, c->remote_maxpacket); 3127 return 0; 3128 } 3129 3130 static char * 3131 reason2txt(int reason) 3132 { 3133 switch (reason) { 3134 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3135 return "administratively prohibited"; 3136 case SSH2_OPEN_CONNECT_FAILED: 3137 return "connect failed"; 3138 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3139 return "unknown channel type"; 3140 case SSH2_OPEN_RESOURCE_SHORTAGE: 3141 return "resource shortage"; 3142 } 3143 return "unknown reason"; 3144 } 3145 3146 int 3147 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3148 { 3149 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3150 u_int32_t reason; 3151 char *msg = NULL; 3152 int r; 3153 3154 if (channel_proxy_upstream(c, type, seq, ssh)) 3155 return 0; 3156 if (c->type != SSH_CHANNEL_OPENING) 3157 packet_disconnect("Received open failure for " 3158 "non-opening channel %d.", c->self); 3159 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3160 error("%s: reason: %s", __func__, ssh_err(r)); 3161 packet_disconnect("Invalid open failure message"); 3162 } 3163 /* skip language */ 3164 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3165 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0) { 3166 error("%s: message/lang: %s", __func__, ssh_err(r)); 3167 packet_disconnect("Invalid open failure message"); 3168 } 3169 ssh_packet_check_eom(ssh); 3170 logit("channel %d: open failed: %s%s%s", c->self, 3171 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3172 free(msg); 3173 if (c->open_confirm) { 3174 debug2("%s: channel %d: callback start", __func__, c->self); 3175 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3176 debug2("%s: channel %d: callback done", __func__, c->self); 3177 } 3178 /* Schedule the channel for cleanup/deletion. */ 3179 chan_mark_dead(ssh, c); 3180 return 0; 3181 } 3182 3183 int 3184 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3185 { 3186 int id = channel_parse_id(ssh, __func__, "window adjust"); 3187 Channel *c; 3188 u_int32_t adjust; 3189 u_int new_rwin; 3190 int r; 3191 3192 if ((c = channel_lookup(ssh, id)) == NULL) { 3193 logit("Received window adjust for non-open channel %d.", id); 3194 return 0; 3195 } 3196 3197 if (channel_proxy_upstream(c, type, seq, ssh)) 3198 return 0; 3199 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0) { 3200 error("%s: adjust: %s", __func__, ssh_err(r)); 3201 packet_disconnect("Invalid window adjust message"); 3202 } 3203 ssh_packet_check_eom(ssh); 3204 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3205 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3206 fatal("channel %d: adjust %u overflows remote window %u", 3207 c->self, adjust, c->remote_window); 3208 } 3209 c->remote_window = new_rwin; 3210 return 0; 3211 } 3212 3213 int 3214 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3215 { 3216 int id = channel_parse_id(ssh, __func__, "status confirm"); 3217 Channel *c; 3218 struct channel_confirm *cc; 3219 3220 /* Reset keepalive timeout */ 3221 packet_set_alive_timeouts(0); 3222 3223 debug2("%s: type %d id %d", __func__, type, id); 3224 3225 if ((c = channel_lookup(ssh, id)) == NULL) { 3226 logit("%s: %d: unknown", __func__, id); 3227 return 0; 3228 } 3229 if (channel_proxy_upstream(c, type, seq, ssh)) 3230 return 0; 3231 ssh_packet_check_eom(ssh); 3232 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3233 return 0; 3234 cc->cb(ssh, type, c, cc->ctx); 3235 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3236 explicit_bzero(cc, sizeof(*cc)); 3237 free(cc); 3238 return 0; 3239 } 3240 3241 /* -- tcp forwarding */ 3242 3243 void 3244 channel_set_af(struct ssh *ssh, int af) 3245 { 3246 ssh->chanctxt->IPv4or6 = af; 3247 } 3248 3249 3250 /* 3251 * Determine whether or not a port forward listens to loopback, the 3252 * specified address or wildcard. On the client, a specified bind 3253 * address will always override gateway_ports. On the server, a 3254 * gateway_ports of 1 (``yes'') will override the client's specification 3255 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3256 * will bind to whatever address the client asked for. 3257 * 3258 * Special-case listen_addrs are: 3259 * 3260 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3261 * "" (empty string), "*" -> wildcard v4/v6 3262 * "localhost" -> loopback v4/v6 3263 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3264 */ 3265 static const char * 3266 channel_fwd_bind_addr(const char *listen_addr, int *wildcardp, 3267 int is_client, struct ForwardOptions *fwd_opts) 3268 { 3269 const char *addr = NULL; 3270 int wildcard = 0; 3271 3272 if (listen_addr == NULL) { 3273 /* No address specified: default to gateway_ports setting */ 3274 if (fwd_opts->gateway_ports) 3275 wildcard = 1; 3276 } else if (fwd_opts->gateway_ports || is_client) { 3277 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 3278 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3279 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3280 (!is_client && fwd_opts->gateway_ports == 1)) { 3281 wildcard = 1; 3282 /* 3283 * Notify client if they requested a specific listen 3284 * address and it was overridden. 3285 */ 3286 if (*listen_addr != '\0' && 3287 strcmp(listen_addr, "0.0.0.0") != 0 && 3288 strcmp(listen_addr, "*") != 0) { 3289 packet_send_debug("Forwarding listen address " 3290 "\"%s\" overridden by server " 3291 "GatewayPorts", listen_addr); 3292 } 3293 } else if (strcmp(listen_addr, "localhost") != 0 || 3294 strcmp(listen_addr, "127.0.0.1") == 0 || 3295 strcmp(listen_addr, "::1") == 0) { 3296 /* Accept localhost address when GatewayPorts=yes */ 3297 addr = listen_addr; 3298 } 3299 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3300 strcmp(listen_addr, "::1") == 0) { 3301 /* 3302 * If a specific IPv4/IPv6 localhost address has been 3303 * requested then accept it even if gateway_ports is in 3304 * effect. This allows the client to prefer IPv4 or IPv6. 3305 */ 3306 addr = listen_addr; 3307 } 3308 if (wildcardp != NULL) 3309 *wildcardp = wildcard; 3310 return addr; 3311 } 3312 3313 static int 3314 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3315 struct Forward *fwd, int *allocated_listen_port, 3316 struct ForwardOptions *fwd_opts) 3317 { 3318 Channel *c; 3319 int sock, r, success = 0, wildcard = 0, is_client; 3320 struct addrinfo hints, *ai, *aitop; 3321 const char *host, *addr; 3322 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3323 in_port_t *lport_p; 3324 3325 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3326 3327 if (is_client && fwd->connect_path != NULL) { 3328 host = fwd->connect_path; 3329 } else { 3330 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3331 fwd->listen_host : fwd->connect_host; 3332 if (host == NULL) { 3333 error("No forward host name."); 3334 return 0; 3335 } 3336 if (strlen(host) >= NI_MAXHOST) { 3337 error("Forward host name too long."); 3338 return 0; 3339 } 3340 } 3341 3342 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3343 addr = channel_fwd_bind_addr(fwd->listen_host, &wildcard, 3344 is_client, fwd_opts); 3345 debug3("%s: type %d wildcard %d addr %s", __func__, 3346 type, wildcard, (addr == NULL) ? "NULL" : addr); 3347 3348 /* 3349 * getaddrinfo returns a loopback address if the hostname is 3350 * set to NULL and hints.ai_flags is not AI_PASSIVE 3351 */ 3352 memset(&hints, 0, sizeof(hints)); 3353 hints.ai_family = ssh->chanctxt->IPv4or6; 3354 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3355 hints.ai_socktype = SOCK_STREAM; 3356 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3357 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3358 if (addr == NULL) { 3359 /* This really shouldn't happen */ 3360 packet_disconnect("getaddrinfo: fatal error: %s", 3361 ssh_gai_strerror(r)); 3362 } else { 3363 error("%s: getaddrinfo(%.64s): %s", __func__, addr, 3364 ssh_gai_strerror(r)); 3365 } 3366 return 0; 3367 } 3368 if (allocated_listen_port != NULL) 3369 *allocated_listen_port = 0; 3370 for (ai = aitop; ai; ai = ai->ai_next) { 3371 switch (ai->ai_family) { 3372 case AF_INET: 3373 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3374 sin_port; 3375 break; 3376 case AF_INET6: 3377 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3378 sin6_port; 3379 break; 3380 default: 3381 continue; 3382 } 3383 /* 3384 * If allocating a port for -R forwards, then use the 3385 * same port for all address families. 3386 */ 3387 if (type == SSH_CHANNEL_RPORT_LISTENER && 3388 fwd->listen_port == 0 && allocated_listen_port != NULL && 3389 *allocated_listen_port > 0) 3390 *lport_p = htons(*allocated_listen_port); 3391 3392 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3393 strport, sizeof(strport), 3394 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3395 error("%s: getnameinfo failed", __func__); 3396 continue; 3397 } 3398 /* Create a port to listen for the host. */ 3399 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3400 if (sock < 0) { 3401 /* this is no error since kernel may not support ipv6 */ 3402 verbose("socket [%s]:%s: %.100s", ntop, strport, 3403 strerror(errno)); 3404 continue; 3405 } 3406 3407 set_reuseaddr(sock); 3408 3409 debug("Local forwarding listening on %s port %s.", 3410 ntop, strport); 3411 3412 /* Bind the socket to the address. */ 3413 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3414 /* 3415 * address can be in if use ipv6 address is 3416 * already bound 3417 */ 3418 verbose("bind [%s]:%s: %.100s", 3419 ntop, strport, strerror(errno)); 3420 close(sock); 3421 continue; 3422 } 3423 /* Start listening for connections on the socket. */ 3424 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 3425 error("listen [%s]:%s: %.100s", ntop, strport, 3426 strerror(errno)); 3427 close(sock); 3428 continue; 3429 } 3430 3431 /* 3432 * fwd->listen_port == 0 requests a dynamically allocated port - 3433 * record what we got. 3434 */ 3435 if (type == SSH_CHANNEL_RPORT_LISTENER && 3436 fwd->listen_port == 0 && 3437 allocated_listen_port != NULL && 3438 *allocated_listen_port == 0) { 3439 *allocated_listen_port = get_local_port(sock); 3440 debug("Allocated listen port %d", 3441 *allocated_listen_port); 3442 } 3443 3444 /* Allocate a channel number for the socket. */ 3445 c = channel_new(ssh, "port listener", type, sock, sock, -1, 3446 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3447 0, "port listener", 1); 3448 c->path = xstrdup(host); 3449 c->host_port = fwd->connect_port; 3450 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3451 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3452 !(datafellows & SSH_BUG_DYNAMIC_RPORT)) 3453 c->listening_port = *allocated_listen_port; 3454 else 3455 c->listening_port = fwd->listen_port; 3456 success = 1; 3457 } 3458 if (success == 0) 3459 error("%s: cannot listen to port: %d", __func__, 3460 fwd->listen_port); 3461 freeaddrinfo(aitop); 3462 return success; 3463 } 3464 3465 static int 3466 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3467 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3468 { 3469 struct sockaddr_un sunaddr; 3470 const char *path; 3471 Channel *c; 3472 int port, sock; 3473 mode_t omask; 3474 3475 switch (type) { 3476 case SSH_CHANNEL_UNIX_LISTENER: 3477 if (fwd->connect_path != NULL) { 3478 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3479 error("Local connecting path too long: %s", 3480 fwd->connect_path); 3481 return 0; 3482 } 3483 path = fwd->connect_path; 3484 port = PORT_STREAMLOCAL; 3485 } else { 3486 if (fwd->connect_host == NULL) { 3487 error("No forward host name."); 3488 return 0; 3489 } 3490 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3491 error("Forward host name too long."); 3492 return 0; 3493 } 3494 path = fwd->connect_host; 3495 port = fwd->connect_port; 3496 } 3497 break; 3498 case SSH_CHANNEL_RUNIX_LISTENER: 3499 path = fwd->listen_path; 3500 port = PORT_STREAMLOCAL; 3501 break; 3502 default: 3503 error("%s: unexpected channel type %d", __func__, type); 3504 return 0; 3505 } 3506 3507 if (fwd->listen_path == NULL) { 3508 error("No forward path name."); 3509 return 0; 3510 } 3511 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3512 error("Local listening path too long: %s", fwd->listen_path); 3513 return 0; 3514 } 3515 3516 debug3("%s: type %d path %s", __func__, type, fwd->listen_path); 3517 3518 /* Start a Unix domain listener. */ 3519 omask = umask(fwd_opts->streamlocal_bind_mask); 3520 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3521 fwd_opts->streamlocal_bind_unlink); 3522 umask(omask); 3523 if (sock < 0) 3524 return 0; 3525 3526 debug("Local forwarding listening on path %s.", fwd->listen_path); 3527 3528 /* Allocate a channel number for the socket. */ 3529 c = channel_new(ssh, "unix listener", type, sock, sock, -1, 3530 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3531 0, "unix listener", 1); 3532 c->path = xstrdup(path); 3533 c->host_port = port; 3534 c->listening_port = PORT_STREAMLOCAL; 3535 c->listening_addr = xstrdup(fwd->listen_path); 3536 return 1; 3537 } 3538 3539 static int 3540 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3541 const char *host, u_short port) 3542 { 3543 u_int i; 3544 int found = 0; 3545 3546 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3547 Channel *c = ssh->chanctxt->channels[i]; 3548 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3549 continue; 3550 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3551 debug2("%s: close channel %d", __func__, i); 3552 channel_free(ssh, c); 3553 found = 1; 3554 } 3555 } 3556 3557 return found; 3558 } 3559 3560 static int 3561 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3562 { 3563 u_int i; 3564 int found = 0; 3565 3566 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3567 Channel *c = ssh->chanctxt->channels[i]; 3568 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3569 continue; 3570 if (c->path == NULL) 3571 continue; 3572 if (strcmp(c->path, path) == 0) { 3573 debug2("%s: close channel %d", __func__, i); 3574 channel_free(ssh, c); 3575 found = 1; 3576 } 3577 } 3578 3579 return found; 3580 } 3581 3582 int 3583 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3584 { 3585 if (fwd->listen_path != NULL) { 3586 return channel_cancel_rport_listener_streamlocal(ssh, 3587 fwd->listen_path); 3588 } else { 3589 return channel_cancel_rport_listener_tcpip(ssh, 3590 fwd->listen_host, fwd->listen_port); 3591 } 3592 } 3593 3594 static int 3595 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 3596 const char *lhost, u_short lport, int cport, 3597 struct ForwardOptions *fwd_opts) 3598 { 3599 u_int i; 3600 int found = 0; 3601 const char *addr = channel_fwd_bind_addr(lhost, NULL, 1, fwd_opts); 3602 3603 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3604 Channel *c = ssh->chanctxt->channels[i]; 3605 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 3606 continue; 3607 if (c->listening_port != lport) 3608 continue; 3609 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 3610 /* skip dynamic forwardings */ 3611 if (c->host_port == 0) 3612 continue; 3613 } else { 3614 if (c->host_port != cport) 3615 continue; 3616 } 3617 if ((c->listening_addr == NULL && addr != NULL) || 3618 (c->listening_addr != NULL && addr == NULL)) 3619 continue; 3620 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 3621 debug2("%s: close channel %d", __func__, i); 3622 channel_free(ssh, c); 3623 found = 1; 3624 } 3625 } 3626 3627 return found; 3628 } 3629 3630 static int 3631 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 3632 { 3633 u_int i; 3634 int found = 0; 3635 3636 if (path == NULL) { 3637 error("%s: no path specified.", __func__); 3638 return 0; 3639 } 3640 3641 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3642 Channel *c = ssh->chanctxt->channels[i]; 3643 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 3644 continue; 3645 if (c->listening_addr == NULL) 3646 continue; 3647 if (strcmp(c->listening_addr, path) == 0) { 3648 debug2("%s: close channel %d", __func__, i); 3649 channel_free(ssh, c); 3650 found = 1; 3651 } 3652 } 3653 3654 return found; 3655 } 3656 3657 int 3658 channel_cancel_lport_listener(struct ssh *ssh, 3659 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 3660 { 3661 if (fwd->listen_path != NULL) { 3662 return channel_cancel_lport_listener_streamlocal(ssh, 3663 fwd->listen_path); 3664 } else { 3665 return channel_cancel_lport_listener_tcpip(ssh, 3666 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 3667 } 3668 } 3669 3670 /* protocol local port fwd, used by ssh */ 3671 int 3672 channel_setup_local_fwd_listener(struct ssh *ssh, 3673 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3674 { 3675 if (fwd->listen_path != NULL) { 3676 return channel_setup_fwd_listener_streamlocal(ssh, 3677 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 3678 } else { 3679 return channel_setup_fwd_listener_tcpip(ssh, 3680 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 3681 } 3682 } 3683 3684 /* Matches a remote forwarding permission against a requested forwarding */ 3685 static int 3686 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 3687 { 3688 int ret; 3689 char *lhost; 3690 3691 /* XXX add ACLs for streamlocal */ 3692 if (fwd->listen_path != NULL) 3693 return 1; 3694 3695 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 3696 return 0; 3697 3698 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 3699 allowed_open->listen_port != fwd->listen_port) 3700 return 0; 3701 3702 /* Match hostnames case-insensitively */ 3703 lhost = xstrdup(fwd->listen_host); 3704 lowercase(lhost); 3705 ret = match_pattern(lhost, allowed_open->listen_host); 3706 free(lhost); 3707 3708 return ret; 3709 } 3710 3711 /* Checks whether a requested remote forwarding is permitted */ 3712 static int 3713 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 3714 { 3715 struct ssh_channels *sc = ssh->chanctxt; 3716 struct permission_set *pset = &sc->remote_perms; 3717 u_int i, permit, permit_adm = 1; 3718 struct permission *perm; 3719 3720 /* XXX apply GatewayPorts override before checking? */ 3721 3722 permit = pset->all_permitted; 3723 if (!permit) { 3724 for (i = 0; i < pset->num_permitted_user; i++) { 3725 perm = &pset->permitted_user[i]; 3726 if (remote_open_match(perm, fwd)) { 3727 permit = 1; 3728 break; 3729 } 3730 } 3731 } 3732 3733 if (pset->num_permitted_admin > 0) { 3734 permit_adm = 0; 3735 for (i = 0; i < pset->num_permitted_admin; i++) { 3736 perm = &pset->permitted_admin[i]; 3737 if (remote_open_match(perm, fwd)) { 3738 permit_adm = 1; 3739 break; 3740 } 3741 } 3742 } 3743 3744 return permit && permit_adm; 3745 } 3746 3747 /* protocol v2 remote port fwd, used by sshd */ 3748 int 3749 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 3750 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 3751 { 3752 if (!check_rfwd_permission(ssh, fwd)) { 3753 packet_send_debug("port forwarding refused"); 3754 return 0; 3755 } 3756 if (fwd->listen_path != NULL) { 3757 return channel_setup_fwd_listener_streamlocal(ssh, 3758 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 3759 } else { 3760 return channel_setup_fwd_listener_tcpip(ssh, 3761 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 3762 fwd_opts); 3763 } 3764 } 3765 3766 /* 3767 * Translate the requested rfwd listen host to something usable for 3768 * this server. 3769 */ 3770 static const char * 3771 channel_rfwd_bind_host(const char *listen_host) 3772 { 3773 if (listen_host == NULL) { 3774 return "localhost"; 3775 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 3776 return ""; 3777 } else 3778 return listen_host; 3779 } 3780 3781 /* 3782 * Initiate forwarding of connections to port "port" on remote host through 3783 * the secure channel to host:port from local side. 3784 * Returns handle (index) for updating the dynamic listen port with 3785 * channel_update_permission(). 3786 */ 3787 int 3788 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 3789 { 3790 int r, success = 0, idx = -1; 3791 char *host_to_connect, *listen_host, *listen_path; 3792 int port_to_connect, listen_port; 3793 3794 /* Send the forward request to the remote side. */ 3795 if (fwd->listen_path != NULL) { 3796 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3797 (r = sshpkt_put_cstring(ssh, 3798 "streamlocal-forward@openssh.com")) != 0 || 3799 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 3800 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 3801 (r = sshpkt_send(ssh)) != 0 || 3802 (r = ssh_packet_write_wait(ssh)) != 0) 3803 fatal("%s: request streamlocal: %s", 3804 __func__, ssh_err(r)); 3805 } else { 3806 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3807 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 3808 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 3809 (r = sshpkt_put_cstring(ssh, 3810 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 3811 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 3812 (r = sshpkt_send(ssh)) != 0 || 3813 (r = ssh_packet_write_wait(ssh)) != 0) 3814 fatal("%s: request tcpip-forward: %s", 3815 __func__, ssh_err(r)); 3816 } 3817 /* Assume that server accepts the request */ 3818 success = 1; 3819 if (success) { 3820 /* Record that connection to this host/port is permitted. */ 3821 host_to_connect = listen_host = listen_path = NULL; 3822 port_to_connect = listen_port = 0; 3823 if (fwd->connect_path != NULL) { 3824 host_to_connect = xstrdup(fwd->connect_path); 3825 port_to_connect = PORT_STREAMLOCAL; 3826 } else { 3827 host_to_connect = xstrdup(fwd->connect_host); 3828 port_to_connect = fwd->connect_port; 3829 } 3830 if (fwd->listen_path != NULL) { 3831 listen_path = xstrdup(fwd->listen_path); 3832 listen_port = PORT_STREAMLOCAL; 3833 } else { 3834 if (fwd->listen_host != NULL) 3835 listen_host = xstrdup(fwd->listen_host); 3836 listen_port = fwd->listen_port; 3837 } 3838 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 3839 host_to_connect, port_to_connect, 3840 listen_host, listen_path, listen_port, NULL); 3841 } 3842 return idx; 3843 } 3844 3845 static int 3846 open_match(struct permission *allowed_open, const char *requestedhost, 3847 int requestedport) 3848 { 3849 if (allowed_open->host_to_connect == NULL) 3850 return 0; 3851 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 3852 allowed_open->port_to_connect != requestedport) 3853 return 0; 3854 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 3855 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 3856 return 0; 3857 return 1; 3858 } 3859 3860 /* 3861 * Note that in the listen host/port case 3862 * we don't support FWD_PERMIT_ANY_PORT and 3863 * need to translate between the configured-host (listen_host) 3864 * and what we've sent to the remote server (channel_rfwd_bind_host) 3865 */ 3866 static int 3867 open_listen_match_tcpip(struct permission *allowed_open, 3868 const char *requestedhost, u_short requestedport, int translate) 3869 { 3870 const char *allowed_host; 3871 3872 if (allowed_open->host_to_connect == NULL) 3873 return 0; 3874 if (allowed_open->listen_port != requestedport) 3875 return 0; 3876 if (!translate && allowed_open->listen_host == NULL && 3877 requestedhost == NULL) 3878 return 1; 3879 allowed_host = translate ? 3880 channel_rfwd_bind_host(allowed_open->listen_host) : 3881 allowed_open->listen_host; 3882 if (allowed_host == NULL || requestedhost == NULL || 3883 strcmp(allowed_host, requestedhost) != 0) 3884 return 0; 3885 return 1; 3886 } 3887 3888 static int 3889 open_listen_match_streamlocal(struct permission *allowed_open, 3890 const char *requestedpath) 3891 { 3892 if (allowed_open->host_to_connect == NULL) 3893 return 0; 3894 if (allowed_open->listen_port != PORT_STREAMLOCAL) 3895 return 0; 3896 if (allowed_open->listen_path == NULL || 3897 strcmp(allowed_open->listen_path, requestedpath) != 0) 3898 return 0; 3899 return 1; 3900 } 3901 3902 /* 3903 * Request cancellation of remote forwarding of connection host:port from 3904 * local side. 3905 */ 3906 static int 3907 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 3908 const char *host, u_short port) 3909 { 3910 struct ssh_channels *sc = ssh->chanctxt; 3911 struct permission_set *pset = &sc->local_perms; 3912 int r; 3913 u_int i; 3914 struct permission *perm; 3915 3916 for (i = 0; i < pset->num_permitted_user; i++) { 3917 perm = &pset->permitted_user[i]; 3918 if (open_listen_match_tcpip(perm, host, port, 0)) 3919 break; 3920 perm = NULL; 3921 } 3922 if (perm == NULL) { 3923 debug("%s: requested forward not found", __func__); 3924 return -1; 3925 } 3926 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3927 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 3928 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 3929 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 3930 (r = sshpkt_put_u32(ssh, port)) != 0 || 3931 (r = sshpkt_send(ssh)) != 0) 3932 fatal("%s: send cancel: %s", __func__, ssh_err(r)); 3933 3934 fwd_perm_clear(perm); /* unregister */ 3935 3936 return 0; 3937 } 3938 3939 /* 3940 * Request cancellation of remote forwarding of Unix domain socket 3941 * path from local side. 3942 */ 3943 static int 3944 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 3945 { 3946 struct ssh_channels *sc = ssh->chanctxt; 3947 struct permission_set *pset = &sc->local_perms; 3948 int r; 3949 u_int i; 3950 struct permission *perm; 3951 3952 for (i = 0; i < pset->num_permitted_user; i++) { 3953 perm = &pset->permitted_user[i]; 3954 if (open_listen_match_streamlocal(perm, path)) 3955 break; 3956 perm = NULL; 3957 } 3958 if (perm == NULL) { 3959 debug("%s: requested forward not found", __func__); 3960 return -1; 3961 } 3962 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3963 (r = sshpkt_put_cstring(ssh, 3964 "cancel-streamlocal-forward@openssh.com")) != 0 || 3965 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 3966 (r = sshpkt_put_cstring(ssh, path)) != 0 || 3967 (r = sshpkt_send(ssh)) != 0) 3968 fatal("%s: send cancel: %s", __func__, ssh_err(r)); 3969 3970 fwd_perm_clear(perm); /* unregister */ 3971 3972 return 0; 3973 } 3974 3975 /* 3976 * Request cancellation of remote forwarding of a connection from local side. 3977 */ 3978 int 3979 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 3980 { 3981 if (fwd->listen_path != NULL) { 3982 return channel_request_rforward_cancel_streamlocal(ssh, 3983 fwd->listen_path); 3984 } else { 3985 return channel_request_rforward_cancel_tcpip(ssh, 3986 fwd->listen_host, 3987 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 3988 } 3989 } 3990 3991 /* 3992 * Permits opening to any host/port if permitted_user[] is empty. This is 3993 * usually called by the server, because the user could connect to any port 3994 * anyway, and the server has no way to know but to trust the client anyway. 3995 */ 3996 void 3997 channel_permit_all(struct ssh *ssh, int where) 3998 { 3999 struct permission_set *pset = permission_set_get(ssh, where); 4000 4001 if (pset->num_permitted_user == 0) 4002 pset->all_permitted = 1; 4003 } 4004 4005 /* 4006 * Permit the specified host/port for forwarding. 4007 */ 4008 void 4009 channel_add_permission(struct ssh *ssh, int who, int where, 4010 char *host, int port) 4011 { 4012 int local = where == FORWARD_LOCAL; 4013 struct permission_set *pset = permission_set_get(ssh, where); 4014 4015 debug("allow %s forwarding to host %s port %d", 4016 fwd_ident(who, where), host, port); 4017 /* 4018 * Remote forwards set listen_host/port, local forwards set 4019 * host/port_to_connect. 4020 */ 4021 permission_set_add(ssh, who, where, 4022 local ? host : 0, local ? port : 0, 4023 local ? NULL : host, NULL, local ? 0 : port, NULL); 4024 pset->all_permitted = 0; 4025 } 4026 4027 /* 4028 * Administratively disable forwarding. 4029 */ 4030 void 4031 channel_disable_admin(struct ssh *ssh, int where) 4032 { 4033 channel_clear_permission(ssh, FORWARD_ADM, where); 4034 permission_set_add(ssh, FORWARD_ADM, where, 4035 NULL, 0, NULL, NULL, 0, NULL); 4036 } 4037 4038 /* 4039 * Clear a list of permitted opens. 4040 */ 4041 void 4042 channel_clear_permission(struct ssh *ssh, int who, int where) 4043 { 4044 struct permission **permp; 4045 u_int *npermp; 4046 4047 permission_set_get_array(ssh, who, where, &permp, &npermp); 4048 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4049 *npermp = 0; 4050 } 4051 4052 /* 4053 * Update the listen port for a dynamic remote forward, after 4054 * the actual 'newport' has been allocated. If 'newport' < 0 is 4055 * passed then they entry will be invalidated. 4056 */ 4057 void 4058 channel_update_permission(struct ssh *ssh, int idx, int newport) 4059 { 4060 struct permission_set *pset = &ssh->chanctxt->local_perms; 4061 4062 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4063 debug("%s: index out of range: %d num_permitted_user %d", 4064 __func__, idx, pset->num_permitted_user); 4065 return; 4066 } 4067 debug("%s allowed port %d for forwarding to host %s port %d", 4068 newport > 0 ? "Updating" : "Removing", 4069 newport, 4070 pset->permitted_user[idx].host_to_connect, 4071 pset->permitted_user[idx].port_to_connect); 4072 if (newport <= 0) 4073 fwd_perm_clear(&pset->permitted_user[idx]); 4074 else { 4075 pset->permitted_user[idx].listen_port = 4076 (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4077 } 4078 } 4079 4080 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4081 int 4082 permitopen_port(const char *p) 4083 { 4084 int port; 4085 4086 if (strcmp(p, "*") == 0) 4087 return FWD_PERMIT_ANY_PORT; 4088 if ((port = a2port(p)) > 0) 4089 return port; 4090 return -1; 4091 } 4092 4093 /* Try to start non-blocking connect to next host in cctx list */ 4094 static int 4095 connect_next(struct channel_connect *cctx) 4096 { 4097 int sock, saved_errno; 4098 struct sockaddr_un *sunaddr; 4099 char ntop[NI_MAXHOST]; 4100 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4101 4102 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4103 switch (cctx->ai->ai_family) { 4104 case AF_UNIX: 4105 /* unix:pathname instead of host:port */ 4106 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4107 strlcpy(ntop, "unix", sizeof(ntop)); 4108 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4109 break; 4110 case AF_INET: 4111 case AF_INET6: 4112 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4113 ntop, sizeof(ntop), strport, sizeof(strport), 4114 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4115 error("connect_next: getnameinfo failed"); 4116 continue; 4117 } 4118 break; 4119 default: 4120 continue; 4121 } 4122 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4123 cctx->ai->ai_protocol)) == -1) { 4124 if (cctx->ai->ai_next == NULL) 4125 error("socket: %.100s", strerror(errno)); 4126 else 4127 verbose("socket: %.100s", strerror(errno)); 4128 continue; 4129 } 4130 if (set_nonblock(sock) == -1) 4131 fatal("%s: set_nonblock(%d)", __func__, sock); 4132 if (connect(sock, cctx->ai->ai_addr, 4133 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4134 debug("connect_next: host %.100s ([%.100s]:%s): " 4135 "%.100s", cctx->host, ntop, strport, 4136 strerror(errno)); 4137 saved_errno = errno; 4138 close(sock); 4139 errno = saved_errno; 4140 continue; /* fail -- try next */ 4141 } 4142 if (cctx->ai->ai_family != AF_UNIX) 4143 set_nodelay(sock); 4144 debug("connect_next: host %.100s ([%.100s]:%s) " 4145 "in progress, fd=%d", cctx->host, ntop, strport, sock); 4146 cctx->ai = cctx->ai->ai_next; 4147 return sock; 4148 } 4149 return -1; 4150 } 4151 4152 static void 4153 channel_connect_ctx_free(struct channel_connect *cctx) 4154 { 4155 free(cctx->host); 4156 if (cctx->aitop) { 4157 if (cctx->aitop->ai_family == AF_UNIX) 4158 free(cctx->aitop); 4159 else 4160 freeaddrinfo(cctx->aitop); 4161 } 4162 memset(cctx, 0, sizeof(*cctx)); 4163 } 4164 4165 /* 4166 * Return connecting socket to remote host:port or local socket path, 4167 * passing back the failure reason if appropriate. 4168 */ 4169 static int 4170 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4171 char *ctype, char *rname, struct channel_connect *cctx, 4172 int *reason, const char **errmsg) 4173 { 4174 struct addrinfo hints; 4175 int gaierr; 4176 int sock = -1; 4177 char strport[NI_MAXSERV]; 4178 4179 if (port == PORT_STREAMLOCAL) { 4180 struct sockaddr_un *sunaddr; 4181 struct addrinfo *ai; 4182 4183 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4184 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4185 return -1; 4186 } 4187 4188 /* 4189 * Fake up a struct addrinfo for AF_UNIX connections. 4190 * channel_connect_ctx_free() must check ai_family 4191 * and use free() not freeaddirinfo() for AF_UNIX. 4192 */ 4193 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4194 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4195 ai->ai_addr = (struct sockaddr *)(ai + 1); 4196 ai->ai_addrlen = sizeof(*sunaddr); 4197 ai->ai_family = AF_UNIX; 4198 ai->ai_socktype = socktype; 4199 ai->ai_protocol = PF_UNSPEC; 4200 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4201 sunaddr->sun_family = AF_UNIX; 4202 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4203 cctx->aitop = ai; 4204 } else { 4205 memset(&hints, 0, sizeof(hints)); 4206 hints.ai_family = ssh->chanctxt->IPv4or6; 4207 hints.ai_socktype = socktype; 4208 snprintf(strport, sizeof strport, "%d", port); 4209 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4210 != 0) { 4211 if (errmsg != NULL) 4212 *errmsg = ssh_gai_strerror(gaierr); 4213 if (reason != NULL) 4214 *reason = SSH2_OPEN_CONNECT_FAILED; 4215 error("connect_to %.100s: unknown host (%s)", name, 4216 ssh_gai_strerror(gaierr)); 4217 return -1; 4218 } 4219 } 4220 4221 cctx->host = xstrdup(name); 4222 cctx->port = port; 4223 cctx->ai = cctx->aitop; 4224 4225 if ((sock = connect_next(cctx)) == -1) { 4226 error("connect to %.100s port %d failed: %s", 4227 name, port, strerror(errno)); 4228 return -1; 4229 } 4230 4231 return sock; 4232 } 4233 4234 /* Return CONNECTING channel to remote host:port or local socket path */ 4235 static Channel * 4236 connect_to(struct ssh *ssh, const char *host, int port, 4237 char *ctype, char *rname) 4238 { 4239 struct channel_connect cctx; 4240 Channel *c; 4241 int sock; 4242 4243 memset(&cctx, 0, sizeof(cctx)); 4244 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4245 &cctx, NULL, NULL); 4246 if (sock == -1) { 4247 channel_connect_ctx_free(&cctx); 4248 return NULL; 4249 } 4250 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4251 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4252 c->host_port = port; 4253 c->path = xstrdup(host); 4254 c->connect_ctx = cctx; 4255 4256 return c; 4257 } 4258 4259 /* 4260 * returns either the newly connected channel or the downstream channel 4261 * that needs to deal with this connection. 4262 */ 4263 Channel * 4264 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4265 u_short listen_port, char *ctype, char *rname) 4266 { 4267 struct ssh_channels *sc = ssh->chanctxt; 4268 struct permission_set *pset = &sc->local_perms; 4269 u_int i; 4270 struct permission *perm; 4271 4272 for (i = 0; i < pset->num_permitted_user; i++) { 4273 perm = &pset->permitted_user[i]; 4274 if (open_listen_match_tcpip(perm, 4275 listen_host, listen_port, 1)) { 4276 if (perm->downstream) 4277 return perm->downstream; 4278 if (perm->port_to_connect == 0) 4279 return rdynamic_connect_prepare(ssh, 4280 ctype, rname); 4281 return connect_to(ssh, 4282 perm->host_to_connect, perm->port_to_connect, 4283 ctype, rname); 4284 } 4285 } 4286 error("WARNING: Server requests forwarding for unknown listen_port %d", 4287 listen_port); 4288 return NULL; 4289 } 4290 4291 Channel * 4292 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4293 char *ctype, char *rname) 4294 { 4295 struct ssh_channels *sc = ssh->chanctxt; 4296 struct permission_set *pset = &sc->local_perms; 4297 u_int i; 4298 struct permission *perm; 4299 4300 for (i = 0; i < pset->num_permitted_user; i++) { 4301 perm = &pset->permitted_user[i]; 4302 if (open_listen_match_streamlocal(perm, path)) { 4303 return connect_to(ssh, 4304 perm->host_to_connect, perm->port_to_connect, 4305 ctype, rname); 4306 } 4307 } 4308 error("WARNING: Server requests forwarding for unknown path %.100s", 4309 path); 4310 return NULL; 4311 } 4312 4313 /* Check if connecting to that port is permitted and connect. */ 4314 Channel * 4315 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4316 char *ctype, char *rname, int *reason, const char **errmsg) 4317 { 4318 struct ssh_channels *sc = ssh->chanctxt; 4319 struct permission_set *pset = &sc->local_perms; 4320 struct channel_connect cctx; 4321 Channel *c; 4322 u_int i, permit, permit_adm = 1; 4323 int sock; 4324 struct permission *perm; 4325 4326 permit = pset->all_permitted; 4327 if (!permit) { 4328 for (i = 0; i < pset->num_permitted_user; i++) { 4329 perm = &pset->permitted_user[i]; 4330 if (open_match(perm, host, port)) { 4331 permit = 1; 4332 break; 4333 } 4334 } 4335 } 4336 4337 if (pset->num_permitted_admin > 0) { 4338 permit_adm = 0; 4339 for (i = 0; i < pset->num_permitted_admin; i++) { 4340 perm = &pset->permitted_admin[i]; 4341 if (open_match(perm, host, port)) { 4342 permit_adm = 1; 4343 break; 4344 } 4345 } 4346 } 4347 4348 if (!permit || !permit_adm) { 4349 logit("Received request to connect to host %.100s port %d, " 4350 "but the request was denied.", host, port); 4351 if (reason != NULL) 4352 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4353 return NULL; 4354 } 4355 4356 memset(&cctx, 0, sizeof(cctx)); 4357 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4358 &cctx, reason, errmsg); 4359 if (sock == -1) { 4360 channel_connect_ctx_free(&cctx); 4361 return NULL; 4362 } 4363 4364 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4365 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4366 c->host_port = port; 4367 c->path = xstrdup(host); 4368 c->connect_ctx = cctx; 4369 4370 return c; 4371 } 4372 4373 /* Check if connecting to that path is permitted and connect. */ 4374 Channel * 4375 channel_connect_to_path(struct ssh *ssh, const char *path, 4376 char *ctype, char *rname) 4377 { 4378 struct ssh_channels *sc = ssh->chanctxt; 4379 struct permission_set *pset = &sc->local_perms; 4380 u_int i, permit, permit_adm = 1; 4381 struct permission *perm; 4382 4383 permit = pset->all_permitted; 4384 if (!permit) { 4385 for (i = 0; i < pset->num_permitted_user; i++) { 4386 perm = &pset->permitted_user[i]; 4387 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4388 permit = 1; 4389 break; 4390 } 4391 } 4392 } 4393 4394 if (pset->num_permitted_admin > 0) { 4395 permit_adm = 0; 4396 for (i = 0; i < pset->num_permitted_admin; i++) { 4397 perm = &pset->permitted_admin[i]; 4398 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4399 permit_adm = 1; 4400 break; 4401 } 4402 } 4403 } 4404 4405 if (!permit || !permit_adm) { 4406 logit("Received request to connect to path %.100s, " 4407 "but the request was denied.", path); 4408 return NULL; 4409 } 4410 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4411 } 4412 4413 void 4414 channel_send_window_changes(struct ssh *ssh) 4415 { 4416 struct ssh_channels *sc = ssh->chanctxt; 4417 struct winsize ws; 4418 int r; 4419 u_int i; 4420 4421 for (i = 0; i < sc->channels_alloc; i++) { 4422 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4423 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4424 continue; 4425 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) < 0) 4426 continue; 4427 channel_request_start(ssh, i, "window-change", 0); 4428 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4429 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4430 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4431 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4432 (r = sshpkt_send(ssh)) != 0) 4433 fatal("%s: channel %u: send window-change: %s", 4434 __func__, i, ssh_err(r)); 4435 } 4436 } 4437 4438 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4439 static Channel * 4440 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4441 { 4442 Channel *c; 4443 int r; 4444 4445 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4446 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4447 c->host_port = 0; 4448 c->path = NULL; 4449 4450 /* 4451 * We need to open the channel before we have a FD, 4452 * so that we can get SOCKS header from peer. 4453 */ 4454 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4455 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4456 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4457 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4458 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 4459 fatal("%s: channel %i: confirm: %s", __func__, 4460 c->self, ssh_err(r)); 4461 } 4462 return c; 4463 } 4464 4465 /* Return CONNECTING socket to remote host:port or local socket path */ 4466 static int 4467 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4468 { 4469 struct channel_connect cctx; 4470 int sock; 4471 4472 memset(&cctx, 0, sizeof(cctx)); 4473 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4474 NULL, &cctx, NULL, NULL); 4475 if (sock == -1) 4476 channel_connect_ctx_free(&cctx); 4477 else { 4478 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4479 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4480 c->connect_ctx = cctx; 4481 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4482 } 4483 return sock; 4484 } 4485 4486 /* -- X11 forwarding */ 4487 4488 /* 4489 * Creates an internet domain socket for listening for X11 connections. 4490 * Returns 0 and a suitable display number for the DISPLAY variable 4491 * stored in display_numberp , or -1 if an error occurs. 4492 */ 4493 int 4494 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4495 int x11_use_localhost, int single_connection, 4496 u_int *display_numberp, int **chanids) 4497 { 4498 Channel *nc = NULL; 4499 int display_number, sock; 4500 u_short port; 4501 struct addrinfo hints, *ai, *aitop; 4502 char strport[NI_MAXSERV]; 4503 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4504 4505 if (chanids == NULL) 4506 return -1; 4507 4508 for (display_number = x11_display_offset; 4509 display_number < MAX_DISPLAYS; 4510 display_number++) { 4511 port = 6000 + display_number; 4512 memset(&hints, 0, sizeof(hints)); 4513 hints.ai_family = ssh->chanctxt->IPv4or6; 4514 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4515 hints.ai_socktype = SOCK_STREAM; 4516 snprintf(strport, sizeof strport, "%d", port); 4517 if ((gaierr = getaddrinfo(NULL, strport, 4518 &hints, &aitop)) != 0) { 4519 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4520 return -1; 4521 } 4522 for (ai = aitop; ai; ai = ai->ai_next) { 4523 if (ai->ai_family != AF_INET && 4524 ai->ai_family != AF_INET6) 4525 continue; 4526 sock = socket(ai->ai_family, ai->ai_socktype, 4527 ai->ai_protocol); 4528 if (sock < 0) { 4529 error("socket: %.100s", strerror(errno)); 4530 freeaddrinfo(aitop); 4531 return -1; 4532 } 4533 set_reuseaddr(sock); 4534 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 4535 debug2("%s: bind port %d: %.100s", __func__, 4536 port, strerror(errno)); 4537 close(sock); 4538 for (n = 0; n < num_socks; n++) 4539 close(socks[n]); 4540 num_socks = 0; 4541 break; 4542 } 4543 socks[num_socks++] = sock; 4544 if (num_socks == NUM_SOCKS) 4545 break; 4546 } 4547 freeaddrinfo(aitop); 4548 if (num_socks > 0) 4549 break; 4550 } 4551 if (display_number >= MAX_DISPLAYS) { 4552 error("Failed to allocate internet-domain X11 display socket."); 4553 return -1; 4554 } 4555 /* Start listening for connections on the socket. */ 4556 for (n = 0; n < num_socks; n++) { 4557 sock = socks[n]; 4558 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 4559 error("listen: %.100s", strerror(errno)); 4560 close(sock); 4561 return -1; 4562 } 4563 } 4564 4565 /* Allocate a channel for each socket. */ 4566 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 4567 for (n = 0; n < num_socks; n++) { 4568 sock = socks[n]; 4569 nc = channel_new(ssh, "x11 listener", 4570 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4571 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 4572 0, "X11 inet listener", 1); 4573 nc->single_connection = single_connection; 4574 (*chanids)[n] = nc->self; 4575 } 4576 (*chanids)[n] = -1; 4577 4578 /* Return the display number for the DISPLAY environment variable. */ 4579 *display_numberp = display_number; 4580 return 0; 4581 } 4582 4583 static int 4584 connect_local_xsocket(u_int dnr) 4585 { 4586 int sock; 4587 struct sockaddr_un addr; 4588 4589 sock = socket(AF_UNIX, SOCK_STREAM, 0); 4590 if (sock < 0) 4591 error("socket: %.100s", strerror(errno)); 4592 memset(&addr, 0, sizeof(addr)); 4593 addr.sun_family = AF_UNIX; 4594 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 4595 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 4596 return sock; 4597 close(sock); 4598 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 4599 return -1; 4600 } 4601 4602 int 4603 x11_connect_display(struct ssh *ssh) 4604 { 4605 u_int display_number; 4606 const char *display; 4607 char buf[1024], *cp; 4608 struct addrinfo hints, *ai, *aitop; 4609 char strport[NI_MAXSERV]; 4610 int gaierr, sock = 0; 4611 4612 /* Try to open a socket for the local X server. */ 4613 display = getenv("DISPLAY"); 4614 if (!display) { 4615 error("DISPLAY not set."); 4616 return -1; 4617 } 4618 /* 4619 * Now we decode the value of the DISPLAY variable and make a 4620 * connection to the real X server. 4621 */ 4622 4623 /* 4624 * Check if it is a unix domain socket. Unix domain displays are in 4625 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 4626 */ 4627 if (strncmp(display, "unix:", 5) == 0 || 4628 display[0] == ':') { 4629 /* Connect to the unix domain socket. */ 4630 if (sscanf(strrchr(display, ':') + 1, "%u", 4631 &display_number) != 1) { 4632 error("Could not parse display number from DISPLAY: " 4633 "%.100s", display); 4634 return -1; 4635 } 4636 /* Create a socket. */ 4637 sock = connect_local_xsocket(display_number); 4638 if (sock < 0) 4639 return -1; 4640 4641 /* OK, we now have a connection to the display. */ 4642 return sock; 4643 } 4644 /* 4645 * Connect to an inet socket. The DISPLAY value is supposedly 4646 * hostname:d[.s], where hostname may also be numeric IP address. 4647 */ 4648 strlcpy(buf, display, sizeof(buf)); 4649 cp = strchr(buf, ':'); 4650 if (!cp) { 4651 error("Could not find ':' in DISPLAY: %.100s", display); 4652 return -1; 4653 } 4654 *cp = 0; 4655 /* 4656 * buf now contains the host name. But first we parse the 4657 * display number. 4658 */ 4659 if (sscanf(cp + 1, "%u", &display_number) != 1) { 4660 error("Could not parse display number from DISPLAY: %.100s", 4661 display); 4662 return -1; 4663 } 4664 4665 /* Look up the host address */ 4666 memset(&hints, 0, sizeof(hints)); 4667 hints.ai_family = ssh->chanctxt->IPv4or6; 4668 hints.ai_socktype = SOCK_STREAM; 4669 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 4670 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 4671 error("%.100s: unknown host. (%s)", buf, 4672 ssh_gai_strerror(gaierr)); 4673 return -1; 4674 } 4675 for (ai = aitop; ai; ai = ai->ai_next) { 4676 /* Create a socket. */ 4677 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 4678 if (sock < 0) { 4679 debug2("socket: %.100s", strerror(errno)); 4680 continue; 4681 } 4682 /* Connect it to the display. */ 4683 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 4684 debug2("connect %.100s port %u: %.100s", buf, 4685 6000 + display_number, strerror(errno)); 4686 close(sock); 4687 continue; 4688 } 4689 /* Success */ 4690 break; 4691 } 4692 freeaddrinfo(aitop); 4693 if (!ai) { 4694 error("connect %.100s port %u: %.100s", buf, 4695 6000 + display_number, strerror(errno)); 4696 return -1; 4697 } 4698 set_nodelay(sock); 4699 return sock; 4700 } 4701 4702 /* 4703 * Requests forwarding of X11 connections, generates fake authentication 4704 * data, and enables authentication spoofing. 4705 * This should be called in the client only. 4706 */ 4707 void 4708 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 4709 const char *disp, const char *proto, const char *data, int want_reply) 4710 { 4711 struct ssh_channels *sc = ssh->chanctxt; 4712 u_int data_len = (u_int) strlen(data) / 2; 4713 u_int i, value; 4714 const char *cp; 4715 char *new_data; 4716 int r, screen_number; 4717 4718 if (sc->x11_saved_display == NULL) 4719 sc->x11_saved_display = xstrdup(disp); 4720 else if (strcmp(disp, sc->x11_saved_display) != 0) { 4721 error("x11_request_forwarding_with_spoofing: different " 4722 "$DISPLAY already forwarded"); 4723 return; 4724 } 4725 4726 cp = strchr(disp, ':'); 4727 if (cp) 4728 cp = strchr(cp, '.'); 4729 if (cp) 4730 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 4731 else 4732 screen_number = 0; 4733 4734 if (sc->x11_saved_proto == NULL) { 4735 /* Save protocol name. */ 4736 sc->x11_saved_proto = xstrdup(proto); 4737 4738 /* Extract real authentication data. */ 4739 sc->x11_saved_data = xmalloc(data_len); 4740 for (i = 0; i < data_len; i++) { 4741 if (sscanf(data + 2 * i, "%2x", &value) != 1) 4742 fatal("x11_request_forwarding: bad " 4743 "authentication data: %.100s", data); 4744 sc->x11_saved_data[i] = value; 4745 } 4746 sc->x11_saved_data_len = data_len; 4747 4748 /* Generate fake data of the same length. */ 4749 sc->x11_fake_data = xmalloc(data_len); 4750 arc4random_buf(sc->x11_fake_data, data_len); 4751 sc->x11_fake_data_len = data_len; 4752 } 4753 4754 /* Convert the fake data into hex. */ 4755 new_data = tohex(sc->x11_fake_data, data_len); 4756 4757 /* Send the request packet. */ 4758 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 4759 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 4760 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 4761 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 4762 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 4763 (r = sshpkt_send(ssh)) != 0 || 4764 (r = ssh_packet_write_wait(ssh)) != 0) 4765 fatal("%s: send x11-req: %s", __func__, ssh_err(r)); 4766 free(new_data); 4767 } 4768