1 /* $OpenBSD: channels.c,v 1.419 2022/05/05 00:56:58 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 <poll.h> 58 #include <stdarg.h> 59 #include <stdint.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <termios.h> 64 #include <unistd.h> 65 66 #include "xmalloc.h" 67 #include "ssh.h" 68 #include "ssh2.h" 69 #include "ssherr.h" 70 #include "sshbuf.h" 71 #include "packet.h" 72 #include "log.h" 73 #include "misc.h" 74 #include "channels.h" 75 #include "compat.h" 76 #include "canohost.h" 77 #include "sshkey.h" 78 #include "authfd.h" 79 #include "pathnames.h" 80 #include "match.h" 81 82 /* XXX remove once we're satisfied there's no lurking bugs */ 83 /* #define DEBUG_CHANNEL_POLL 1 */ 84 85 /* -- agent forwarding */ 86 #define NUM_SOCKS 10 87 88 /* -- tcp forwarding */ 89 /* special-case port number meaning allow any port */ 90 #define FWD_PERMIT_ANY_PORT 0 91 92 /* special-case wildcard meaning allow any host */ 93 #define FWD_PERMIT_ANY_HOST "*" 94 95 /* -- X11 forwarding */ 96 /* Maximum number of fake X11 displays to try. */ 97 #define MAX_DISPLAYS 1000 98 99 /* Per-channel callback for pre/post IO actions */ 100 typedef void chan_fn(struct ssh *, Channel *c); 101 102 /* 103 * Data structure for storing which hosts are permitted for forward requests. 104 * The local sides of any remote forwards are stored in this array to prevent 105 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 106 * network (which might be behind a firewall). 107 */ 108 /* XXX: streamlocal wants a path instead of host:port */ 109 /* Overload host_to_connect; we could just make this match Forward */ 110 /* XXX - can we use listen_host instead of listen_path? */ 111 struct permission { 112 char *host_to_connect; /* Connect to 'host'. */ 113 int port_to_connect; /* Connect to 'port'. */ 114 char *listen_host; /* Remote side should listen address. */ 115 char *listen_path; /* Remote side should listen path. */ 116 int listen_port; /* Remote side should listen port. */ 117 Channel *downstream; /* Downstream mux*/ 118 }; 119 120 /* 121 * Stores the forwarding permission state for a single direction (local or 122 * remote). 123 */ 124 struct permission_set { 125 /* 126 * List of all local permitted host/port pairs to allow for the 127 * user. 128 */ 129 u_int num_permitted_user; 130 struct permission *permitted_user; 131 132 /* 133 * List of all permitted host/port pairs to allow for the admin. 134 */ 135 u_int num_permitted_admin; 136 struct permission *permitted_admin; 137 138 /* 139 * If this is true, all opens/listens are permitted. This is the 140 * case on the server on which we have to trust the client anyway, 141 * and the user could do anything after logging in. 142 */ 143 int all_permitted; 144 }; 145 146 /* Master structure for channels state */ 147 struct ssh_channels { 148 /* 149 * Pointer to an array containing all allocated channels. The array 150 * is dynamically extended as needed. 151 */ 152 Channel **channels; 153 154 /* 155 * Size of the channel array. All slots of the array must always be 156 * initialized (at least the type field); unused slots set to NULL 157 */ 158 u_int channels_alloc; 159 160 /* 161 * 'channel_pre*' are called just before IO to add any bits 162 * relevant to channels in the c->io_want bitmasks. 163 * 164 * 'channel_post*': perform any appropriate operations for 165 * channels which have c->io_ready events pending. 166 */ 167 chan_fn **channel_pre; 168 chan_fn **channel_post; 169 170 /* -- tcp forwarding */ 171 struct permission_set local_perms; 172 struct permission_set remote_perms; 173 174 /* -- X11 forwarding */ 175 176 /* Saved X11 local (client) display. */ 177 char *x11_saved_display; 178 179 /* Saved X11 authentication protocol name. */ 180 char *x11_saved_proto; 181 182 /* Saved X11 authentication data. This is the real data. */ 183 char *x11_saved_data; 184 u_int x11_saved_data_len; 185 186 /* Deadline after which all X11 connections are refused */ 187 u_int x11_refuse_time; 188 189 /* 190 * Fake X11 authentication data. This is what the server will be 191 * sending us; we should replace any occurrences of this by the 192 * real data. 193 */ 194 u_char *x11_fake_data; 195 u_int x11_fake_data_len; 196 197 /* AF_UNSPEC or AF_INET or AF_INET6 */ 198 int IPv4or6; 199 }; 200 201 /* helper */ 202 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 203 static const char *channel_rfwd_bind_host(const char *listen_host); 204 205 /* non-blocking connect helpers */ 206 static int connect_next(struct channel_connect *); 207 static void channel_connect_ctx_free(struct channel_connect *); 208 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 209 static int rdynamic_connect_finish(struct ssh *, Channel *); 210 211 /* Setup helper */ 212 static void channel_handler_init(struct ssh_channels *sc); 213 214 /* -- channel core */ 215 216 void 217 channel_init_channels(struct ssh *ssh) 218 { 219 struct ssh_channels *sc; 220 221 if ((sc = calloc(1, sizeof(*sc))) == NULL) 222 fatal_f("allocation failed"); 223 sc->channels_alloc = 10; 224 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 225 sc->IPv4or6 = AF_UNSPEC; 226 channel_handler_init(sc); 227 228 ssh->chanctxt = sc; 229 } 230 231 Channel * 232 channel_by_id(struct ssh *ssh, int id) 233 { 234 Channel *c; 235 236 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 237 logit_f("%d: bad id", id); 238 return NULL; 239 } 240 c = ssh->chanctxt->channels[id]; 241 if (c == NULL) { 242 logit_f("%d: bad id: channel free", id); 243 return NULL; 244 } 245 return c; 246 } 247 248 Channel * 249 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 250 { 251 Channel *c; 252 u_int i; 253 254 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 255 c = ssh->chanctxt->channels[i]; 256 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 257 return c; 258 } 259 return NULL; 260 } 261 262 /* 263 * Returns the channel if it is allowed to receive protocol messages. 264 * Private channels, like listening sockets, may not receive messages. 265 */ 266 Channel * 267 channel_lookup(struct ssh *ssh, int id) 268 { 269 Channel *c; 270 271 if ((c = channel_by_id(ssh, id)) == NULL) 272 return NULL; 273 274 switch (c->type) { 275 case SSH_CHANNEL_X11_OPEN: 276 case SSH_CHANNEL_LARVAL: 277 case SSH_CHANNEL_CONNECTING: 278 case SSH_CHANNEL_DYNAMIC: 279 case SSH_CHANNEL_RDYNAMIC_OPEN: 280 case SSH_CHANNEL_RDYNAMIC_FINISH: 281 case SSH_CHANNEL_OPENING: 282 case SSH_CHANNEL_OPEN: 283 case SSH_CHANNEL_ABANDONED: 284 case SSH_CHANNEL_MUX_PROXY: 285 return c; 286 } 287 logit("Non-public channel %d, type %d.", id, c->type); 288 return NULL; 289 } 290 291 /* 292 * Register filedescriptors for a channel, used when allocating a channel or 293 * when the channel consumer/producer is ready, e.g. shell exec'd 294 */ 295 static void 296 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 297 int extusage, int nonblock, int is_tty) 298 { 299 int val; 300 301 if (rfd != -1) 302 fcntl(rfd, F_SETFD, FD_CLOEXEC); 303 if (wfd != -1 && wfd != rfd) 304 fcntl(wfd, F_SETFD, FD_CLOEXEC); 305 if (efd != -1 && efd != rfd && efd != wfd) 306 fcntl(efd, F_SETFD, FD_CLOEXEC); 307 308 c->rfd = rfd; 309 c->wfd = wfd; 310 c->sock = (rfd == wfd) ? rfd : -1; 311 c->efd = efd; 312 c->extended_usage = extusage; 313 314 if ((c->isatty = is_tty) != 0) 315 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 316 317 /* enable nonblocking mode */ 318 c->restore_block = 0; 319 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 320 /* 321 * Special handling for stdio file descriptors: do not set 322 * non-blocking mode if they are TTYs. Otherwise prepare to 323 * restore their blocking state on exit to avoid interfering 324 * with other programs that follow. 325 */ 326 if (rfd != -1 && !isatty(rfd) && 327 (val = fcntl(rfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 328 c->restore_block |= CHANNEL_RESTORE_RFD; 329 set_nonblock(rfd); 330 } 331 if (wfd != -1 && !isatty(wfd) && 332 (val = fcntl(wfd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 333 c->restore_block |= CHANNEL_RESTORE_WFD; 334 set_nonblock(wfd); 335 } 336 if (efd != -1 && !isatty(efd) && 337 (val = fcntl(efd, F_GETFL)) != -1 && !(val & O_NONBLOCK)) { 338 c->restore_block |= CHANNEL_RESTORE_EFD; 339 set_nonblock(efd); 340 } 341 } else if (nonblock) { 342 if (rfd != -1) 343 set_nonblock(rfd); 344 if (wfd != -1) 345 set_nonblock(wfd); 346 if (efd != -1) 347 set_nonblock(efd); 348 } 349 } 350 351 /* 352 * Allocate a new channel object and set its type and socket. 353 */ 354 Channel * 355 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 356 u_int window, u_int maxpack, int extusage, const char *remote_name, 357 int nonblock) 358 { 359 struct ssh_channels *sc = ssh->chanctxt; 360 u_int i, found; 361 Channel *c; 362 int r; 363 364 /* Try to find a free slot where to put the new channel. */ 365 for (i = 0; i < sc->channels_alloc; i++) { 366 if (sc->channels[i] == NULL) { 367 /* Found a free slot. */ 368 found = i; 369 break; 370 } 371 } 372 if (i >= sc->channels_alloc) { 373 /* 374 * There are no free slots. Take last+1 slot and expand 375 * the array. 376 */ 377 found = sc->channels_alloc; 378 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 379 fatal_f("internal error: channels_alloc %d too big", 380 sc->channels_alloc); 381 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 382 sc->channels_alloc + 10, sizeof(*sc->channels)); 383 sc->channels_alloc += 10; 384 debug2("channel: expanding %d", sc->channels_alloc); 385 } 386 /* Initialize and return new channel. */ 387 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 388 if ((c->input = sshbuf_new()) == NULL || 389 (c->output = sshbuf_new()) == NULL || 390 (c->extended = sshbuf_new()) == NULL) 391 fatal_f("sshbuf_new failed"); 392 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 393 fatal_fr(r, "sshbuf_set_max_size"); 394 c->ostate = CHAN_OUTPUT_OPEN; 395 c->istate = CHAN_INPUT_OPEN; 396 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 397 c->self = found; 398 c->type = type; 399 c->ctype = ctype; 400 c->local_window = window; 401 c->local_window_max = window; 402 c->local_maxpacket = maxpack; 403 c->remote_name = xstrdup(remote_name); 404 c->ctl_chan = -1; 405 c->delayed = 1; /* prevent call to channel_post handler */ 406 TAILQ_INIT(&c->status_confirms); 407 debug("channel %d: new [%s]", found, remote_name); 408 return c; 409 } 410 411 int 412 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 413 { 414 int ret, fd = *fdp; 415 416 if (fd == -1) 417 return 0; 418 419 if ((*fdp == c->rfd && (c->restore_block & CHANNEL_RESTORE_RFD) != 0) || 420 (*fdp == c->wfd && (c->restore_block & CHANNEL_RESTORE_WFD) != 0) || 421 (*fdp == c->efd && (c->restore_block & CHANNEL_RESTORE_EFD) != 0)) 422 (void)fcntl(*fdp, F_SETFL, 0); /* restore blocking */ 423 424 if (*fdp == c->rfd) { 425 c->io_want &= ~SSH_CHAN_IO_RFD; 426 c->io_ready &= ~SSH_CHAN_IO_RFD; 427 c->rfd = -1; 428 c->pfds[0] = -1; 429 } 430 if (*fdp == c->wfd) { 431 c->io_want &= ~SSH_CHAN_IO_WFD; 432 c->io_ready &= ~SSH_CHAN_IO_WFD; 433 c->wfd = -1; 434 c->pfds[1] = -1; 435 } 436 if (*fdp == c->efd) { 437 c->io_want &= ~SSH_CHAN_IO_EFD; 438 c->io_ready &= ~SSH_CHAN_IO_EFD; 439 c->efd = -1; 440 c->pfds[2] = -1; 441 } 442 if (*fdp == c->sock) { 443 c->io_want &= ~SSH_CHAN_IO_SOCK; 444 c->io_ready &= ~SSH_CHAN_IO_SOCK; 445 c->sock = -1; 446 c->pfds[3] = -1; 447 } 448 449 ret = close(fd); 450 *fdp = -1; /* probably redundant */ 451 return ret; 452 } 453 454 /* Close all channel fd/socket. */ 455 static void 456 channel_close_fds(struct ssh *ssh, Channel *c) 457 { 458 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 459 460 channel_close_fd(ssh, c, &c->sock); 461 if (rfd != sock) 462 channel_close_fd(ssh, c, &c->rfd); 463 if (wfd != sock && wfd != rfd) 464 channel_close_fd(ssh, c, &c->wfd); 465 if (efd != sock && efd != rfd && efd != wfd) 466 channel_close_fd(ssh, c, &c->efd); 467 } 468 469 static void 470 fwd_perm_clear(struct permission *perm) 471 { 472 free(perm->host_to_connect); 473 free(perm->listen_host); 474 free(perm->listen_path); 475 memset(perm, 0, sizeof(*perm)); 476 } 477 478 /* Returns an printable name for the specified forwarding permission list */ 479 static const char * 480 fwd_ident(int who, int where) 481 { 482 if (who == FORWARD_ADM) { 483 if (where == FORWARD_LOCAL) 484 return "admin local"; 485 else if (where == FORWARD_REMOTE) 486 return "admin remote"; 487 } else if (who == FORWARD_USER) { 488 if (where == FORWARD_LOCAL) 489 return "user local"; 490 else if (where == FORWARD_REMOTE) 491 return "user remote"; 492 } 493 fatal("Unknown forward permission list %d/%d", who, where); 494 } 495 496 /* Returns the forwarding permission list for the specified direction */ 497 static struct permission_set * 498 permission_set_get(struct ssh *ssh, int where) 499 { 500 struct ssh_channels *sc = ssh->chanctxt; 501 502 switch (where) { 503 case FORWARD_LOCAL: 504 return &sc->local_perms; 505 break; 506 case FORWARD_REMOTE: 507 return &sc->remote_perms; 508 break; 509 default: 510 fatal_f("invalid forwarding direction %d", where); 511 } 512 } 513 514 /* Returns pointers to the specified forwarding list and its element count */ 515 static void 516 permission_set_get_array(struct ssh *ssh, int who, int where, 517 struct permission ***permpp, u_int **npermpp) 518 { 519 struct permission_set *pset = permission_set_get(ssh, where); 520 521 switch (who) { 522 case FORWARD_USER: 523 *permpp = &pset->permitted_user; 524 *npermpp = &pset->num_permitted_user; 525 break; 526 case FORWARD_ADM: 527 *permpp = &pset->permitted_admin; 528 *npermpp = &pset->num_permitted_admin; 529 break; 530 default: 531 fatal_f("invalid forwarding client %d", who); 532 } 533 } 534 535 /* Adds an entry to the specified forwarding list */ 536 static int 537 permission_set_add(struct ssh *ssh, int who, int where, 538 const char *host_to_connect, int port_to_connect, 539 const char *listen_host, const char *listen_path, int listen_port, 540 Channel *downstream) 541 { 542 struct permission **permp; 543 u_int n, *npermp; 544 545 permission_set_get_array(ssh, who, where, &permp, &npermp); 546 547 if (*npermp >= INT_MAX) 548 fatal_f("%s overflow", fwd_ident(who, where)); 549 550 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 551 n = (*npermp)++; 552 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 553 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 554 (*permp)[n].port_to_connect = port_to_connect; 555 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 556 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 557 (*permp)[n].listen_port = listen_port; 558 (*permp)[n].downstream = downstream; 559 #undef MAYBE_DUP 560 return (int)n; 561 } 562 563 static void 564 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 565 { 566 struct ssh_channels *sc = ssh->chanctxt; 567 struct permission_set *pset = &sc->local_perms; 568 struct permission *perm; 569 int r; 570 u_int i; 571 572 for (i = 0; i < pset->num_permitted_user; i++) { 573 perm = &pset->permitted_user[i]; 574 if (perm->downstream != c) 575 continue; 576 577 /* cancel on the server, since mux client is gone */ 578 debug("channel %d: cleanup remote forward for %s:%u", 579 c->self, perm->listen_host, perm->listen_port); 580 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 581 (r = sshpkt_put_cstring(ssh, 582 "cancel-tcpip-forward")) != 0 || 583 (r = sshpkt_put_u8(ssh, 0)) != 0 || 584 (r = sshpkt_put_cstring(ssh, 585 channel_rfwd_bind_host(perm->listen_host))) != 0 || 586 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 587 (r = sshpkt_send(ssh)) != 0) { 588 fatal_fr(r, "channel %i", c->self); 589 } 590 fwd_perm_clear(perm); /* unregister */ 591 } 592 } 593 594 /* Free the channel and close its fd/socket. */ 595 void 596 channel_free(struct ssh *ssh, Channel *c) 597 { 598 struct ssh_channels *sc = ssh->chanctxt; 599 char *s; 600 u_int i, n; 601 Channel *other; 602 struct channel_confirm *cc; 603 604 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 605 if ((other = sc->channels[i]) == NULL) 606 continue; 607 n++; 608 /* detach from mux client and prepare for closing */ 609 if (c->type == SSH_CHANNEL_MUX_CLIENT && 610 other->type == SSH_CHANNEL_MUX_PROXY && 611 other->mux_ctx == c) { 612 other->mux_ctx = NULL; 613 other->type = SSH_CHANNEL_OPEN; 614 other->istate = CHAN_INPUT_CLOSED; 615 other->ostate = CHAN_OUTPUT_CLOSED; 616 } 617 } 618 debug("channel %d: free: %s, nchannels %u", c->self, 619 c->remote_name ? c->remote_name : "???", n); 620 621 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 622 mux_remove_remote_forwardings(ssh, c); 623 free(c->mux_ctx); 624 c->mux_ctx = NULL; 625 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 626 free(c->mux_ctx); 627 c->mux_ctx = NULL; 628 } 629 630 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 631 s = channel_open_message(ssh); 632 debug3("channel %d: status: %s", c->self, s); 633 free(s); 634 } 635 636 channel_close_fds(ssh, c); 637 sshbuf_free(c->input); 638 sshbuf_free(c->output); 639 sshbuf_free(c->extended); 640 c->input = c->output = c->extended = NULL; 641 free(c->remote_name); 642 c->remote_name = NULL; 643 free(c->path); 644 c->path = NULL; 645 free(c->listening_addr); 646 c->listening_addr = NULL; 647 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 648 if (cc->abandon_cb != NULL) 649 cc->abandon_cb(ssh, c, cc->ctx); 650 TAILQ_REMOVE(&c->status_confirms, cc, entry); 651 freezero(cc, sizeof(*cc)); 652 } 653 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 654 c->filter_cleanup(ssh, c->self, c->filter_ctx); 655 sc->channels[c->self] = NULL; 656 freezero(c, sizeof(*c)); 657 } 658 659 void 660 channel_free_all(struct ssh *ssh) 661 { 662 u_int i; 663 struct ssh_channels *sc = ssh->chanctxt; 664 665 for (i = 0; i < sc->channels_alloc; i++) 666 if (sc->channels[i] != NULL) 667 channel_free(ssh, sc->channels[i]); 668 669 free(sc->channels); 670 sc->channels = NULL; 671 sc->channels_alloc = 0; 672 673 free(sc->x11_saved_display); 674 sc->x11_saved_display = NULL; 675 676 free(sc->x11_saved_proto); 677 sc->x11_saved_proto = NULL; 678 679 free(sc->x11_saved_data); 680 sc->x11_saved_data = NULL; 681 sc->x11_saved_data_len = 0; 682 683 free(sc->x11_fake_data); 684 sc->x11_fake_data = NULL; 685 sc->x11_fake_data_len = 0; 686 } 687 688 /* 689 * Closes the sockets/fds of all channels. This is used to close extra file 690 * descriptors after a fork. 691 */ 692 void 693 channel_close_all(struct ssh *ssh) 694 { 695 u_int i; 696 697 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 698 if (ssh->chanctxt->channels[i] != NULL) 699 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 700 } 701 702 /* 703 * Stop listening to channels. 704 */ 705 void 706 channel_stop_listening(struct ssh *ssh) 707 { 708 u_int i; 709 Channel *c; 710 711 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 712 c = ssh->chanctxt->channels[i]; 713 if (c != NULL) { 714 switch (c->type) { 715 case SSH_CHANNEL_AUTH_SOCKET: 716 case SSH_CHANNEL_PORT_LISTENER: 717 case SSH_CHANNEL_RPORT_LISTENER: 718 case SSH_CHANNEL_X11_LISTENER: 719 case SSH_CHANNEL_UNIX_LISTENER: 720 case SSH_CHANNEL_RUNIX_LISTENER: 721 channel_close_fd(ssh, c, &c->sock); 722 channel_free(ssh, c); 723 break; 724 } 725 } 726 } 727 } 728 729 /* 730 * Returns true if no channel has too much buffered data, and false if one or 731 * more channel is overfull. 732 */ 733 int 734 channel_not_very_much_buffered_data(struct ssh *ssh) 735 { 736 u_int i; 737 u_int maxsize = ssh_packet_get_maxsize(ssh); 738 Channel *c; 739 740 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 741 c = ssh->chanctxt->channels[i]; 742 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 743 continue; 744 if (sshbuf_len(c->output) > maxsize) { 745 debug2("channel %d: big output buffer %zu > %u", 746 c->self, sshbuf_len(c->output), maxsize); 747 return 0; 748 } 749 } 750 return 1; 751 } 752 753 /* Returns true if any channel is still open. */ 754 int 755 channel_still_open(struct ssh *ssh) 756 { 757 u_int i; 758 Channel *c; 759 760 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 761 c = ssh->chanctxt->channels[i]; 762 if (c == NULL) 763 continue; 764 switch (c->type) { 765 case SSH_CHANNEL_X11_LISTENER: 766 case SSH_CHANNEL_PORT_LISTENER: 767 case SSH_CHANNEL_RPORT_LISTENER: 768 case SSH_CHANNEL_MUX_LISTENER: 769 case SSH_CHANNEL_CLOSED: 770 case SSH_CHANNEL_AUTH_SOCKET: 771 case SSH_CHANNEL_DYNAMIC: 772 case SSH_CHANNEL_RDYNAMIC_OPEN: 773 case SSH_CHANNEL_CONNECTING: 774 case SSH_CHANNEL_ZOMBIE: 775 case SSH_CHANNEL_ABANDONED: 776 case SSH_CHANNEL_UNIX_LISTENER: 777 case SSH_CHANNEL_RUNIX_LISTENER: 778 continue; 779 case SSH_CHANNEL_LARVAL: 780 continue; 781 case SSH_CHANNEL_OPENING: 782 case SSH_CHANNEL_OPEN: 783 case SSH_CHANNEL_RDYNAMIC_FINISH: 784 case SSH_CHANNEL_X11_OPEN: 785 case SSH_CHANNEL_MUX_CLIENT: 786 case SSH_CHANNEL_MUX_PROXY: 787 return 1; 788 default: 789 fatal_f("bad channel type %d", c->type); 790 /* NOTREACHED */ 791 } 792 } 793 return 0; 794 } 795 796 /* Returns the id of an open channel suitable for keepaliving */ 797 int 798 channel_find_open(struct ssh *ssh) 799 { 800 u_int i; 801 Channel *c; 802 803 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 804 c = ssh->chanctxt->channels[i]; 805 if (c == NULL || !c->have_remote_id) 806 continue; 807 switch (c->type) { 808 case SSH_CHANNEL_CLOSED: 809 case SSH_CHANNEL_DYNAMIC: 810 case SSH_CHANNEL_RDYNAMIC_OPEN: 811 case SSH_CHANNEL_RDYNAMIC_FINISH: 812 case SSH_CHANNEL_X11_LISTENER: 813 case SSH_CHANNEL_PORT_LISTENER: 814 case SSH_CHANNEL_RPORT_LISTENER: 815 case SSH_CHANNEL_MUX_LISTENER: 816 case SSH_CHANNEL_MUX_CLIENT: 817 case SSH_CHANNEL_MUX_PROXY: 818 case SSH_CHANNEL_OPENING: 819 case SSH_CHANNEL_CONNECTING: 820 case SSH_CHANNEL_ZOMBIE: 821 case SSH_CHANNEL_ABANDONED: 822 case SSH_CHANNEL_UNIX_LISTENER: 823 case SSH_CHANNEL_RUNIX_LISTENER: 824 continue; 825 case SSH_CHANNEL_LARVAL: 826 case SSH_CHANNEL_AUTH_SOCKET: 827 case SSH_CHANNEL_OPEN: 828 case SSH_CHANNEL_X11_OPEN: 829 return i; 830 default: 831 fatal_f("bad channel type %d", c->type); 832 /* NOTREACHED */ 833 } 834 } 835 return -1; 836 } 837 838 /* Returns the state of the channel's extended usage flag */ 839 const char * 840 channel_format_extended_usage(const Channel *c) 841 { 842 if (c->efd == -1) 843 return "closed"; 844 845 switch (c->extended_usage) { 846 case CHAN_EXTENDED_WRITE: 847 return "write"; 848 case CHAN_EXTENDED_READ: 849 return "read"; 850 case CHAN_EXTENDED_IGNORE: 851 return "ignore"; 852 default: 853 return "UNKNOWN"; 854 } 855 } 856 857 static char * 858 channel_format_status(const Channel *c) 859 { 860 char *ret = NULL; 861 862 xasprintf(&ret, "t%d %s%u i%u/%zu o%u/%zu e[%s]/%zu " 863 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 864 c->type, 865 c->have_remote_id ? "r" : "nr", c->remote_id, 866 c->istate, sshbuf_len(c->input), 867 c->ostate, sshbuf_len(c->output), 868 channel_format_extended_usage(c), sshbuf_len(c->extended), 869 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 870 c->io_want, c->io_ready); 871 return ret; 872 } 873 874 /* 875 * Returns a message describing the currently open forwarded connections, 876 * suitable for sending to the client. The message contains crlf pairs for 877 * newlines. 878 */ 879 char * 880 channel_open_message(struct ssh *ssh) 881 { 882 struct sshbuf *buf; 883 Channel *c; 884 u_int i; 885 int r; 886 char *cp, *ret; 887 888 if ((buf = sshbuf_new()) == NULL) 889 fatal_f("sshbuf_new"); 890 if ((r = sshbuf_putf(buf, 891 "The following connections are open:\r\n")) != 0) 892 fatal_fr(r, "sshbuf_putf"); 893 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 894 c = ssh->chanctxt->channels[i]; 895 if (c == NULL) 896 continue; 897 switch (c->type) { 898 case SSH_CHANNEL_X11_LISTENER: 899 case SSH_CHANNEL_PORT_LISTENER: 900 case SSH_CHANNEL_RPORT_LISTENER: 901 case SSH_CHANNEL_CLOSED: 902 case SSH_CHANNEL_AUTH_SOCKET: 903 case SSH_CHANNEL_ZOMBIE: 904 case SSH_CHANNEL_ABANDONED: 905 case SSH_CHANNEL_MUX_LISTENER: 906 case SSH_CHANNEL_UNIX_LISTENER: 907 case SSH_CHANNEL_RUNIX_LISTENER: 908 continue; 909 case SSH_CHANNEL_LARVAL: 910 case SSH_CHANNEL_OPENING: 911 case SSH_CHANNEL_CONNECTING: 912 case SSH_CHANNEL_DYNAMIC: 913 case SSH_CHANNEL_RDYNAMIC_OPEN: 914 case SSH_CHANNEL_RDYNAMIC_FINISH: 915 case SSH_CHANNEL_OPEN: 916 case SSH_CHANNEL_X11_OPEN: 917 case SSH_CHANNEL_MUX_PROXY: 918 case SSH_CHANNEL_MUX_CLIENT: 919 cp = channel_format_status(c); 920 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 921 c->self, c->remote_name, cp)) != 0) { 922 free(cp); 923 fatal_fr(r, "sshbuf_putf"); 924 } 925 free(cp); 926 continue; 927 default: 928 fatal_f("bad channel type %d", c->type); 929 /* NOTREACHED */ 930 } 931 } 932 if ((ret = sshbuf_dup_string(buf)) == NULL) 933 fatal_f("sshbuf_dup_string"); 934 sshbuf_free(buf); 935 return ret; 936 } 937 938 static void 939 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 940 { 941 int r; 942 943 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 944 (r = sshpkt_put_cstring(ssh, type)) != 0 || 945 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 946 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 947 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 948 fatal_r(r, "%s: channel %i: open", where, c->self); 949 } 950 } 951 952 void 953 channel_send_open(struct ssh *ssh, int id) 954 { 955 Channel *c = channel_lookup(ssh, id); 956 int r; 957 958 if (c == NULL) { 959 logit("channel_send_open: %d: bad id", id); 960 return; 961 } 962 debug2("channel %d: send open", id); 963 open_preamble(ssh, __func__, c, c->ctype); 964 if ((r = sshpkt_send(ssh)) != 0) 965 fatal_fr(r, "channel %i", c->self); 966 } 967 968 void 969 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 970 { 971 Channel *c = channel_lookup(ssh, id); 972 int r; 973 974 if (c == NULL) { 975 logit_f("%d: unknown channel id", id); 976 return; 977 } 978 if (!c->have_remote_id) 979 fatal_f("channel %d: no remote id", c->self); 980 981 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 982 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 983 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 984 (r = sshpkt_put_cstring(ssh, service)) != 0 || 985 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 986 fatal_fr(r, "channel %i", c->self); 987 } 988 } 989 990 void 991 channel_register_status_confirm(struct ssh *ssh, int id, 992 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 993 { 994 struct channel_confirm *cc; 995 Channel *c; 996 997 if ((c = channel_lookup(ssh, id)) == NULL) 998 fatal_f("%d: bad id", id); 999 1000 cc = xcalloc(1, sizeof(*cc)); 1001 cc->cb = cb; 1002 cc->abandon_cb = abandon_cb; 1003 cc->ctx = ctx; 1004 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1005 } 1006 1007 void 1008 channel_register_open_confirm(struct ssh *ssh, int id, 1009 channel_open_fn *fn, void *ctx) 1010 { 1011 Channel *c = channel_lookup(ssh, id); 1012 1013 if (c == NULL) { 1014 logit_f("%d: bad id", id); 1015 return; 1016 } 1017 c->open_confirm = fn; 1018 c->open_confirm_ctx = ctx; 1019 } 1020 1021 void 1022 channel_register_cleanup(struct ssh *ssh, int id, 1023 channel_callback_fn *fn, int do_close) 1024 { 1025 Channel *c = channel_by_id(ssh, id); 1026 1027 if (c == NULL) { 1028 logit_f("%d: bad id", id); 1029 return; 1030 } 1031 c->detach_user = fn; 1032 c->detach_close = do_close; 1033 } 1034 1035 void 1036 channel_cancel_cleanup(struct ssh *ssh, int id) 1037 { 1038 Channel *c = channel_by_id(ssh, id); 1039 1040 if (c == NULL) { 1041 logit_f("%d: bad id", id); 1042 return; 1043 } 1044 c->detach_user = NULL; 1045 c->detach_close = 0; 1046 } 1047 1048 void 1049 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1050 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1051 { 1052 Channel *c = channel_lookup(ssh, id); 1053 1054 if (c == NULL) { 1055 logit_f("%d: bad id", id); 1056 return; 1057 } 1058 c->input_filter = ifn; 1059 c->output_filter = ofn; 1060 c->filter_ctx = ctx; 1061 c->filter_cleanup = cfn; 1062 } 1063 1064 void 1065 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1066 int extusage, int nonblock, int is_tty, u_int window_max) 1067 { 1068 Channel *c = channel_lookup(ssh, id); 1069 int r; 1070 1071 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1072 fatal("channel_activate for non-larval channel %d.", id); 1073 if (!c->have_remote_id) 1074 fatal_f("channel %d: no remote id", c->self); 1075 1076 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1077 c->type = SSH_CHANNEL_OPEN; 1078 c->local_window = c->local_window_max = window_max; 1079 1080 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1081 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1082 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1083 (r = sshpkt_send(ssh)) != 0) 1084 fatal_fr(r, "channel %i", c->self); 1085 } 1086 1087 static void 1088 channel_pre_listener(struct ssh *ssh, Channel *c) 1089 { 1090 c->io_want = SSH_CHAN_IO_SOCK_R; 1091 } 1092 1093 static void 1094 channel_pre_connecting(struct ssh *ssh, Channel *c) 1095 { 1096 debug3("channel %d: waiting for connection", c->self); 1097 c->io_want = SSH_CHAN_IO_SOCK_W; 1098 } 1099 1100 static void 1101 channel_pre_open(struct ssh *ssh, Channel *c) 1102 { 1103 c->io_want = 0; 1104 if (c->istate == CHAN_INPUT_OPEN && 1105 c->remote_window > 0 && 1106 sshbuf_len(c->input) < c->remote_window && 1107 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1108 c->io_want |= SSH_CHAN_IO_RFD; 1109 if (c->ostate == CHAN_OUTPUT_OPEN || 1110 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1111 if (sshbuf_len(c->output) > 0) { 1112 c->io_want |= SSH_CHAN_IO_WFD; 1113 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1114 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1115 debug2("channel %d: " 1116 "obuf_empty delayed efd %d/(%zu)", c->self, 1117 c->efd, sshbuf_len(c->extended)); 1118 else 1119 chan_obuf_empty(ssh, c); 1120 } 1121 } 1122 /** XXX check close conditions, too */ 1123 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1124 c->ostate == CHAN_OUTPUT_CLOSED)) { 1125 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1126 sshbuf_len(c->extended) > 0) 1127 c->io_want |= SSH_CHAN_IO_EFD_W; 1128 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1129 (c->extended_usage == CHAN_EXTENDED_READ || 1130 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1131 sshbuf_len(c->extended) < c->remote_window) 1132 c->io_want |= SSH_CHAN_IO_EFD_R; 1133 } 1134 /* XXX: What about efd? races? */ 1135 } 1136 1137 /* 1138 * This is a special state for X11 authentication spoofing. An opened X11 1139 * connection (when authentication spoofing is being done) remains in this 1140 * state until the first packet has been completely read. The authentication 1141 * data in that packet is then substituted by the real data if it matches the 1142 * fake data, and the channel is put into normal mode. 1143 * XXX All this happens at the client side. 1144 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1145 */ 1146 static int 1147 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1148 { 1149 struct ssh_channels *sc = ssh->chanctxt; 1150 u_char *ucp; 1151 u_int proto_len, data_len; 1152 1153 /* Is this being called after the refusal deadline? */ 1154 if (sc->x11_refuse_time != 0 && 1155 (u_int)monotime() >= sc->x11_refuse_time) { 1156 verbose("Rejected X11 connection after ForwardX11Timeout " 1157 "expired"); 1158 return -1; 1159 } 1160 1161 /* Check if the fixed size part of the packet is in buffer. */ 1162 if (sshbuf_len(b) < 12) 1163 return 0; 1164 1165 /* Parse the lengths of variable-length fields. */ 1166 ucp = sshbuf_mutable_ptr(b); 1167 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1168 proto_len = 256 * ucp[6] + ucp[7]; 1169 data_len = 256 * ucp[8] + ucp[9]; 1170 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1171 proto_len = ucp[6] + 256 * ucp[7]; 1172 data_len = ucp[8] + 256 * ucp[9]; 1173 } else { 1174 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1175 ucp[0]); 1176 return -1; 1177 } 1178 1179 /* Check if the whole packet is in buffer. */ 1180 if (sshbuf_len(b) < 1181 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1182 return 0; 1183 1184 /* Check if authentication protocol matches. */ 1185 if (proto_len != strlen(sc->x11_saved_proto) || 1186 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1187 debug2("X11 connection uses different authentication protocol."); 1188 return -1; 1189 } 1190 /* Check if authentication data matches our fake data. */ 1191 if (data_len != sc->x11_fake_data_len || 1192 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1193 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1194 debug2("X11 auth data does not match fake data."); 1195 return -1; 1196 } 1197 /* Check fake data length */ 1198 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1199 error("X11 fake_data_len %d != saved_data_len %d", 1200 sc->x11_fake_data_len, sc->x11_saved_data_len); 1201 return -1; 1202 } 1203 /* 1204 * Received authentication protocol and data match 1205 * our fake data. Substitute the fake data with real 1206 * data. 1207 */ 1208 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1209 sc->x11_saved_data, sc->x11_saved_data_len); 1210 return 1; 1211 } 1212 1213 static void 1214 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1215 { 1216 int ret = x11_open_helper(ssh, c->output); 1217 1218 /* c->force_drain = 1; */ 1219 1220 if (ret == 1) { 1221 c->type = SSH_CHANNEL_OPEN; 1222 channel_pre_open(ssh, c); 1223 } else if (ret == -1) { 1224 logit("X11 connection rejected because of wrong authentication."); 1225 debug2("X11 rejected %d i%d/o%d", 1226 c->self, c->istate, c->ostate); 1227 chan_read_failed(ssh, c); 1228 sshbuf_reset(c->input); 1229 chan_ibuf_empty(ssh, c); 1230 sshbuf_reset(c->output); 1231 chan_write_failed(ssh, c); 1232 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1233 } 1234 } 1235 1236 static void 1237 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1238 { 1239 c->io_want = 0; 1240 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1241 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1242 c->io_want |= SSH_CHAN_IO_RFD; 1243 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1244 /* clear buffer immediately (discard any partial packet) */ 1245 sshbuf_reset(c->input); 1246 chan_ibuf_empty(ssh, c); 1247 /* Start output drain. XXX just kill chan? */ 1248 chan_rcvd_oclose(ssh, c); 1249 } 1250 if (c->ostate == CHAN_OUTPUT_OPEN || 1251 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1252 if (sshbuf_len(c->output) > 0) 1253 c->io_want |= SSH_CHAN_IO_WFD; 1254 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1255 chan_obuf_empty(ssh, c); 1256 } 1257 } 1258 1259 /* try to decode a socks4 header */ 1260 static int 1261 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1262 { 1263 const u_char *p; 1264 char *host; 1265 u_int len, have, i, found, need; 1266 char username[256]; 1267 struct { 1268 u_int8_t version; 1269 u_int8_t command; 1270 u_int16_t dest_port; 1271 struct in_addr dest_addr; 1272 } s4_req, s4_rsp; 1273 int r; 1274 1275 debug2("channel %d: decode socks4", c->self); 1276 1277 have = sshbuf_len(input); 1278 len = sizeof(s4_req); 1279 if (have < len) 1280 return 0; 1281 p = sshbuf_ptr(input); 1282 1283 need = 1; 1284 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1285 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1286 debug2("channel %d: socks4a request", c->self); 1287 /* ... and needs an extra string (the hostname) */ 1288 need = 2; 1289 } 1290 /* Check for terminating NUL on the string(s) */ 1291 for (found = 0, i = len; i < have; i++) { 1292 if (p[i] == '\0') { 1293 found++; 1294 if (found == need) 1295 break; 1296 } 1297 if (i > 1024) { 1298 /* the peer is probably sending garbage */ 1299 debug("channel %d: decode socks4: too long", 1300 c->self); 1301 return -1; 1302 } 1303 } 1304 if (found < need) 1305 return 0; 1306 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1307 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1308 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1309 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1310 debug_r(r, "channels %d: decode socks4", c->self); 1311 return -1; 1312 } 1313 have = sshbuf_len(input); 1314 p = sshbuf_ptr(input); 1315 if (memchr(p, '\0', have) == NULL) { 1316 error("channel %d: decode socks4: unterminated user", c->self); 1317 return -1; 1318 } 1319 len = strlen(p); 1320 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1321 len++; /* trailing '\0' */ 1322 strlcpy(username, p, sizeof(username)); 1323 if ((r = sshbuf_consume(input, len)) != 0) 1324 fatal_fr(r, "channel %d: consume", c->self); 1325 free(c->path); 1326 c->path = NULL; 1327 if (need == 1) { /* SOCKS4: one string */ 1328 host = inet_ntoa(s4_req.dest_addr); 1329 c->path = xstrdup(host); 1330 } else { /* SOCKS4A: two strings */ 1331 have = sshbuf_len(input); 1332 p = sshbuf_ptr(input); 1333 if (memchr(p, '\0', have) == NULL) { 1334 error("channel %d: decode socks4a: host not nul " 1335 "terminated", c->self); 1336 return -1; 1337 } 1338 len = strlen(p); 1339 debug2("channel %d: decode socks4a: host %s/%d", 1340 c->self, p, len); 1341 len++; /* trailing '\0' */ 1342 if (len > NI_MAXHOST) { 1343 error("channel %d: hostname \"%.100s\" too long", 1344 c->self, p); 1345 return -1; 1346 } 1347 c->path = xstrdup(p); 1348 if ((r = sshbuf_consume(input, len)) != 0) 1349 fatal_fr(r, "channel %d: consume", c->self); 1350 } 1351 c->host_port = ntohs(s4_req.dest_port); 1352 1353 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1354 c->self, c->path, c->host_port, s4_req.command); 1355 1356 if (s4_req.command != 1) { 1357 debug("channel %d: cannot handle: %s cn %d", 1358 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1359 return -1; 1360 } 1361 s4_rsp.version = 0; /* vn: 0 for reply */ 1362 s4_rsp.command = 90; /* cd: req granted */ 1363 s4_rsp.dest_port = 0; /* ignored */ 1364 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1365 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1366 fatal_fr(r, "channel %d: append reply", c->self); 1367 return 1; 1368 } 1369 1370 /* try to decode a socks5 header */ 1371 #define SSH_SOCKS5_AUTHDONE 0x1000 1372 #define SSH_SOCKS5_NOAUTH 0x00 1373 #define SSH_SOCKS5_IPV4 0x01 1374 #define SSH_SOCKS5_DOMAIN 0x03 1375 #define SSH_SOCKS5_IPV6 0x04 1376 #define SSH_SOCKS5_CONNECT 0x01 1377 #define SSH_SOCKS5_SUCCESS 0x00 1378 1379 static int 1380 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1381 { 1382 /* XXX use get/put_u8 instead of trusting struct padding */ 1383 struct { 1384 u_int8_t version; 1385 u_int8_t command; 1386 u_int8_t reserved; 1387 u_int8_t atyp; 1388 } s5_req, s5_rsp; 1389 u_int16_t dest_port; 1390 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1391 const u_char *p; 1392 u_int have, need, i, found, nmethods, addrlen, af; 1393 int r; 1394 1395 debug2("channel %d: decode socks5", c->self); 1396 p = sshbuf_ptr(input); 1397 if (p[0] != 0x05) 1398 return -1; 1399 have = sshbuf_len(input); 1400 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1401 /* format: ver | nmethods | methods */ 1402 if (have < 2) 1403 return 0; 1404 nmethods = p[1]; 1405 if (have < nmethods + 2) 1406 return 0; 1407 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1408 for (found = 0, i = 2; i < nmethods + 2; i++) { 1409 if (p[i] == SSH_SOCKS5_NOAUTH) { 1410 found = 1; 1411 break; 1412 } 1413 } 1414 if (!found) { 1415 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1416 c->self); 1417 return -1; 1418 } 1419 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1420 fatal_fr(r, "channel %d: consume", c->self); 1421 /* version, method */ 1422 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1423 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1424 fatal_fr(r, "channel %d: append reply", c->self); 1425 c->flags |= SSH_SOCKS5_AUTHDONE; 1426 debug2("channel %d: socks5 auth done", c->self); 1427 return 0; /* need more */ 1428 } 1429 debug2("channel %d: socks5 post auth", c->self); 1430 if (have < sizeof(s5_req)+1) 1431 return 0; /* need more */ 1432 memcpy(&s5_req, p, sizeof(s5_req)); 1433 if (s5_req.version != 0x05 || 1434 s5_req.command != SSH_SOCKS5_CONNECT || 1435 s5_req.reserved != 0x00) { 1436 debug2("channel %d: only socks5 connect supported", c->self); 1437 return -1; 1438 } 1439 switch (s5_req.atyp){ 1440 case SSH_SOCKS5_IPV4: 1441 addrlen = 4; 1442 af = AF_INET; 1443 break; 1444 case SSH_SOCKS5_DOMAIN: 1445 addrlen = p[sizeof(s5_req)]; 1446 af = -1; 1447 break; 1448 case SSH_SOCKS5_IPV6: 1449 addrlen = 16; 1450 af = AF_INET6; 1451 break; 1452 default: 1453 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1454 return -1; 1455 } 1456 need = sizeof(s5_req) + addrlen + 2; 1457 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1458 need++; 1459 if (have < need) 1460 return 0; 1461 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1462 fatal_fr(r, "channel %d: consume", c->self); 1463 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1464 /* host string length */ 1465 if ((r = sshbuf_consume(input, 1)) != 0) 1466 fatal_fr(r, "channel %d: consume", c->self); 1467 } 1468 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1469 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1470 debug_r(r, "channel %d: parse addr/port", c->self); 1471 return -1; 1472 } 1473 dest_addr[addrlen] = '\0'; 1474 free(c->path); 1475 c->path = NULL; 1476 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1477 if (addrlen >= NI_MAXHOST) { 1478 error("channel %d: dynamic request: socks5 hostname " 1479 "\"%.100s\" too long", c->self, dest_addr); 1480 return -1; 1481 } 1482 c->path = xstrdup(dest_addr); 1483 } else { 1484 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1485 return -1; 1486 c->path = xstrdup(ntop); 1487 } 1488 c->host_port = ntohs(dest_port); 1489 1490 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1491 c->self, c->path, c->host_port, s5_req.command); 1492 1493 s5_rsp.version = 0x05; 1494 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1495 s5_rsp.reserved = 0; /* ignored */ 1496 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1497 dest_port = 0; /* ignored */ 1498 1499 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1500 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1501 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1502 fatal_fr(r, "channel %d: append reply", c->self); 1503 return 1; 1504 } 1505 1506 Channel * 1507 channel_connect_stdio_fwd(struct ssh *ssh, 1508 const char *host_to_connect, u_short port_to_connect, 1509 int in, int out, int nonblock) 1510 { 1511 Channel *c; 1512 1513 debug_f("%s:%d", host_to_connect, port_to_connect); 1514 1515 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1516 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1517 0, "stdio-forward", nonblock); 1518 1519 c->path = xstrdup(host_to_connect); 1520 c->host_port = port_to_connect; 1521 c->listening_port = 0; 1522 c->force_drain = 1; 1523 1524 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1525 port_open_helper(ssh, c, "direct-tcpip"); 1526 1527 return c; 1528 } 1529 1530 /* dynamic port forwarding */ 1531 static void 1532 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1533 { 1534 const u_char *p; 1535 u_int have; 1536 int ret; 1537 1538 c->io_want = 0; 1539 have = sshbuf_len(c->input); 1540 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1541 /* sshbuf_dump(c->input, stderr); */ 1542 /* check if the fixed size part of the packet is in buffer. */ 1543 if (have < 3) { 1544 /* need more */ 1545 c->io_want |= SSH_CHAN_IO_RFD; 1546 return; 1547 } 1548 /* try to guess the protocol */ 1549 p = sshbuf_ptr(c->input); 1550 /* XXX sshbuf_peek_u8? */ 1551 switch (p[0]) { 1552 case 0x04: 1553 ret = channel_decode_socks4(c, c->input, c->output); 1554 break; 1555 case 0x05: 1556 ret = channel_decode_socks5(c, c->input, c->output); 1557 break; 1558 default: 1559 ret = -1; 1560 break; 1561 } 1562 if (ret < 0) { 1563 chan_mark_dead(ssh, c); 1564 } else if (ret == 0) { 1565 debug2("channel %d: pre_dynamic: need more", c->self); 1566 /* need more */ 1567 c->io_want |= SSH_CHAN_IO_RFD; 1568 if (sshbuf_len(c->output)) 1569 c->io_want |= SSH_CHAN_IO_WFD; 1570 } else { 1571 /* switch to the next state */ 1572 c->type = SSH_CHANNEL_OPENING; 1573 port_open_helper(ssh, c, "direct-tcpip"); 1574 } 1575 } 1576 1577 /* simulate read-error */ 1578 static void 1579 rdynamic_close(struct ssh *ssh, Channel *c) 1580 { 1581 c->type = SSH_CHANNEL_OPEN; 1582 chan_read_failed(ssh, c); 1583 sshbuf_reset(c->input); 1584 chan_ibuf_empty(ssh, c); 1585 sshbuf_reset(c->output); 1586 chan_write_failed(ssh, c); 1587 } 1588 1589 /* reverse dynamic port forwarding */ 1590 static void 1591 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1592 { 1593 const u_char *p; 1594 u_int have, len; 1595 int r, ret; 1596 1597 have = sshbuf_len(c->output); 1598 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1599 /* sshbuf_dump(c->output, stderr); */ 1600 /* EOF received */ 1601 if (c->flags & CHAN_EOF_RCVD) { 1602 if ((r = sshbuf_consume(c->output, have)) != 0) 1603 fatal_fr(r, "channel %d: consume", c->self); 1604 rdynamic_close(ssh, c); 1605 return; 1606 } 1607 /* check if the fixed size part of the packet is in buffer. */ 1608 if (have < 3) 1609 return; 1610 /* try to guess the protocol */ 1611 p = sshbuf_ptr(c->output); 1612 switch (p[0]) { 1613 case 0x04: 1614 /* switch input/output for reverse forwarding */ 1615 ret = channel_decode_socks4(c, c->output, c->input); 1616 break; 1617 case 0x05: 1618 ret = channel_decode_socks5(c, c->output, c->input); 1619 break; 1620 default: 1621 ret = -1; 1622 break; 1623 } 1624 if (ret < 0) { 1625 rdynamic_close(ssh, c); 1626 } else if (ret == 0) { 1627 debug2("channel %d: pre_rdynamic: need more", c->self); 1628 /* send socks request to peer */ 1629 len = sshbuf_len(c->input); 1630 if (len > 0 && len < c->remote_window) { 1631 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1632 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1633 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1634 (r = sshpkt_send(ssh)) != 0) { 1635 fatal_fr(r, "channel %i: rdynamic", c->self); 1636 } 1637 if ((r = sshbuf_consume(c->input, len)) != 0) 1638 fatal_fr(r, "channel %d: consume", c->self); 1639 c->remote_window -= len; 1640 } 1641 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1642 /* the connect failed */ 1643 rdynamic_close(ssh, c); 1644 } 1645 } 1646 1647 /* This is our fake X11 server socket. */ 1648 static void 1649 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1650 { 1651 Channel *nc; 1652 struct sockaddr_storage addr; 1653 int r, newsock, oerrno, remote_port; 1654 socklen_t addrlen; 1655 char buf[16384], *remote_ipaddr; 1656 1657 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1658 return; 1659 1660 debug("X11 connection requested."); 1661 addrlen = sizeof(addr); 1662 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1663 if (c->single_connection) { 1664 oerrno = errno; 1665 debug2("single_connection: closing X11 listener."); 1666 channel_close_fd(ssh, c, &c->sock); 1667 chan_mark_dead(ssh, c); 1668 errno = oerrno; 1669 } 1670 if (newsock == -1) { 1671 if (errno != EINTR && errno != EWOULDBLOCK && 1672 errno != ECONNABORTED) 1673 error("accept: %.100s", strerror(errno)); 1674 if (errno == EMFILE || errno == ENFILE) 1675 c->notbefore = monotime() + 1; 1676 return; 1677 } 1678 set_nodelay(newsock); 1679 remote_ipaddr = get_peer_ipaddr(newsock); 1680 remote_port = get_peer_port(newsock); 1681 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1682 remote_ipaddr, remote_port); 1683 1684 nc = channel_new(ssh, "accepted x11 socket", 1685 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1686 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1687 open_preamble(ssh, __func__, nc, "x11"); 1688 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1689 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1690 fatal_fr(r, "channel %i: reply", c->self); 1691 } 1692 if ((r = sshpkt_send(ssh)) != 0) 1693 fatal_fr(r, "channel %i: send", c->self); 1694 free(remote_ipaddr); 1695 } 1696 1697 static void 1698 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1699 { 1700 char *local_ipaddr = get_local_ipaddr(c->sock); 1701 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1702 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1703 int remote_port = get_peer_port(c->sock); 1704 int r; 1705 1706 if (remote_port == -1) { 1707 /* Fake addr/port to appease peers that validate it (Tectia) */ 1708 free(remote_ipaddr); 1709 remote_ipaddr = xstrdup("127.0.0.1"); 1710 remote_port = 65535; 1711 } 1712 1713 free(c->remote_name); 1714 xasprintf(&c->remote_name, 1715 "%s: listening port %d for %.100s port %d, " 1716 "connect from %.200s port %d to %.100s port %d", 1717 rtype, c->listening_port, c->path, c->host_port, 1718 remote_ipaddr, remote_port, local_ipaddr, local_port); 1719 1720 open_preamble(ssh, __func__, c, rtype); 1721 if (strcmp(rtype, "direct-tcpip") == 0) { 1722 /* target host, port */ 1723 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1724 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1725 fatal_fr(r, "channel %i: reply", c->self); 1726 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1727 /* target path */ 1728 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1729 fatal_fr(r, "channel %i: reply", c->self); 1730 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1731 /* listen path */ 1732 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1733 fatal_fr(r, "channel %i: reply", c->self); 1734 } else { 1735 /* listen address, port */ 1736 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1737 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1738 fatal_fr(r, "channel %i: reply", c->self); 1739 } 1740 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1741 /* reserved for future owner/mode info */ 1742 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1743 fatal_fr(r, "channel %i: reply", c->self); 1744 } else { 1745 /* originator host and port */ 1746 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1747 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1748 fatal_fr(r, "channel %i: reply", c->self); 1749 } 1750 if ((r = sshpkt_send(ssh)) != 0) 1751 fatal_fr(r, "channel %i: send", c->self); 1752 free(remote_ipaddr); 1753 free(local_ipaddr); 1754 } 1755 1756 void 1757 channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time) 1758 { 1759 ssh->chanctxt->x11_refuse_time = refuse_time; 1760 } 1761 1762 /* 1763 * This socket is listening for connections to a forwarded TCP/IP port. 1764 */ 1765 static void 1766 channel_post_port_listener(struct ssh *ssh, Channel *c) 1767 { 1768 Channel *nc; 1769 struct sockaddr_storage addr; 1770 int newsock, nextstate; 1771 socklen_t addrlen; 1772 char *rtype; 1773 1774 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1775 return; 1776 1777 debug("Connection to port %d forwarding to %.100s port %d requested.", 1778 c->listening_port, c->path, c->host_port); 1779 1780 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1781 nextstate = SSH_CHANNEL_OPENING; 1782 rtype = "forwarded-tcpip"; 1783 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1784 nextstate = SSH_CHANNEL_OPENING; 1785 rtype = "forwarded-streamlocal@openssh.com"; 1786 } else if (c->host_port == PORT_STREAMLOCAL) { 1787 nextstate = SSH_CHANNEL_OPENING; 1788 rtype = "direct-streamlocal@openssh.com"; 1789 } else if (c->host_port == 0) { 1790 nextstate = SSH_CHANNEL_DYNAMIC; 1791 rtype = "dynamic-tcpip"; 1792 } else { 1793 nextstate = SSH_CHANNEL_OPENING; 1794 rtype = "direct-tcpip"; 1795 } 1796 1797 addrlen = sizeof(addr); 1798 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1799 if (newsock == -1) { 1800 if (errno != EINTR && errno != EWOULDBLOCK && 1801 errno != ECONNABORTED) 1802 error("accept: %.100s", strerror(errno)); 1803 if (errno == EMFILE || errno == ENFILE) 1804 c->notbefore = monotime() + 1; 1805 return; 1806 } 1807 if (c->host_port != PORT_STREAMLOCAL) 1808 set_nodelay(newsock); 1809 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1810 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1811 nc->listening_port = c->listening_port; 1812 nc->host_port = c->host_port; 1813 if (c->path != NULL) 1814 nc->path = xstrdup(c->path); 1815 1816 if (nextstate != SSH_CHANNEL_DYNAMIC) 1817 port_open_helper(ssh, nc, rtype); 1818 } 1819 1820 /* 1821 * This is the authentication agent socket listening for connections from 1822 * clients. 1823 */ 1824 static void 1825 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1826 { 1827 Channel *nc; 1828 int r, newsock; 1829 struct sockaddr_storage addr; 1830 socklen_t addrlen; 1831 1832 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1833 return; 1834 1835 addrlen = sizeof(addr); 1836 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1837 if (newsock == -1) { 1838 error("accept from auth socket: %.100s", strerror(errno)); 1839 if (errno == EMFILE || errno == ENFILE) 1840 c->notbefore = monotime() + 1; 1841 return; 1842 } 1843 nc = channel_new(ssh, "accepted auth socket", 1844 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1845 c->local_window_max, c->local_maxpacket, 1846 0, "accepted auth socket", 1); 1847 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1848 if ((r = sshpkt_send(ssh)) != 0) 1849 fatal_fr(r, "channel %i", c->self); 1850 } 1851 1852 static void 1853 channel_post_connecting(struct ssh *ssh, Channel *c) 1854 { 1855 int err = 0, sock, isopen, r; 1856 socklen_t sz = sizeof(err); 1857 1858 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 1859 return; 1860 if (!c->have_remote_id) 1861 fatal_f("channel %d: no remote id", c->self); 1862 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1863 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1864 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 1865 err = errno; 1866 error("getsockopt SO_ERROR failed"); 1867 } 1868 if (err == 0) { 1869 debug("channel %d: connected to %s port %d", 1870 c->self, c->connect_ctx.host, c->connect_ctx.port); 1871 channel_connect_ctx_free(&c->connect_ctx); 1872 c->type = SSH_CHANNEL_OPEN; 1873 if (isopen) { 1874 /* no message necessary */ 1875 } else { 1876 if ((r = sshpkt_start(ssh, 1877 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1878 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1879 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1880 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1881 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1882 (r = sshpkt_send(ssh)) != 0) 1883 fatal_fr(r, "channel %i open confirm", c->self); 1884 } 1885 } else { 1886 debug("channel %d: connection failed: %s", 1887 c->self, strerror(err)); 1888 /* Try next address, if any */ 1889 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1890 close(c->sock); 1891 c->sock = c->rfd = c->wfd = sock; 1892 return; 1893 } 1894 /* Exhausted all addresses */ 1895 error("connect_to %.100s port %d: failed.", 1896 c->connect_ctx.host, c->connect_ctx.port); 1897 channel_connect_ctx_free(&c->connect_ctx); 1898 if (isopen) { 1899 rdynamic_close(ssh, c); 1900 } else { 1901 if ((r = sshpkt_start(ssh, 1902 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1903 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1904 (r = sshpkt_put_u32(ssh, 1905 SSH2_OPEN_CONNECT_FAILED)) != 0 || 1906 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 1907 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1908 (r = sshpkt_send(ssh)) != 0) 1909 fatal_fr(r, "channel %i: failure", c->self); 1910 chan_mark_dead(ssh, c); 1911 } 1912 } 1913 } 1914 1915 static int 1916 channel_handle_rfd(struct ssh *ssh, Channel *c) 1917 { 1918 char buf[CHAN_RBUF]; 1919 ssize_t len; 1920 int r; 1921 size_t have, avail, maxlen = CHANNEL_MAX_READ; 1922 1923 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 1924 return 1; /* Shouldn't happen */ 1925 if ((avail = sshbuf_avail(c->input)) == 0) 1926 return 1; /* Shouldn't happen */ 1927 1928 /* 1929 * For "simple" channels (i.e. not datagram or filtered), we can 1930 * read directly to the channel buffer. 1931 */ 1932 if (c->input_filter == NULL && !c->datagram) { 1933 /* Only OPEN channels have valid rwin */ 1934 if (c->type == SSH_CHANNEL_OPEN) { 1935 if ((have = sshbuf_len(c->input)) >= c->remote_window) 1936 return 1; /* shouldn't happen */ 1937 if (maxlen > c->remote_window - have) 1938 maxlen = c->remote_window - have; 1939 } 1940 if (maxlen > avail) 1941 maxlen = avail; 1942 if ((r = sshbuf_read(c->rfd, c->input, maxlen, NULL)) != 0) { 1943 if (errno == EINTR || errno == EAGAIN) 1944 return 1; 1945 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 1946 c->self, c->rfd, maxlen, ssh_err(r)); 1947 goto rfail; 1948 } 1949 return 1; 1950 } 1951 1952 len = read(c->rfd, buf, sizeof(buf)); 1953 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 1954 return 1; 1955 if (len <= 0) { 1956 debug2("channel %d: read<=0 rfd %d len %zd: %s", 1957 c->self, c->rfd, len, 1958 len == 0 ? "closed" : strerror(errno)); 1959 rfail: 1960 if (c->type != SSH_CHANNEL_OPEN) { 1961 debug2("channel %d: not open", c->self); 1962 chan_mark_dead(ssh, c); 1963 return -1; 1964 } else { 1965 chan_read_failed(ssh, c); 1966 } 1967 return -1; 1968 } 1969 if (c->input_filter != NULL) { 1970 if (c->input_filter(ssh, c, buf, len) == -1) { 1971 debug2("channel %d: filter stops", c->self); 1972 chan_read_failed(ssh, c); 1973 } 1974 } else if (c->datagram) { 1975 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 1976 fatal_fr(r, "channel %i: put datagram", c->self); 1977 } 1978 return 1; 1979 } 1980 1981 static int 1982 channel_handle_wfd(struct ssh *ssh, Channel *c) 1983 { 1984 struct termios tio; 1985 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 1986 size_t dlen, olen = 0; 1987 int r, len; 1988 1989 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 1990 return 1; 1991 if (sshbuf_len(c->output) == 0) 1992 return 1; 1993 1994 /* Send buffered output data to the socket. */ 1995 olen = sshbuf_len(c->output); 1996 if (c->output_filter != NULL) { 1997 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 1998 debug2("channel %d: filter stops", c->self); 1999 if (c->type != SSH_CHANNEL_OPEN) 2000 chan_mark_dead(ssh, c); 2001 else 2002 chan_write_failed(ssh, c); 2003 return -1; 2004 } 2005 } else if (c->datagram) { 2006 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2007 fatal_fr(r, "channel %i: get datagram", c->self); 2008 buf = data; 2009 } else { 2010 buf = data = sshbuf_mutable_ptr(c->output); 2011 dlen = sshbuf_len(c->output); 2012 } 2013 2014 if (c->datagram) { 2015 /* ignore truncated writes, datagrams might get lost */ 2016 len = write(c->wfd, buf, dlen); 2017 free(data); 2018 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2019 return 1; 2020 if (len <= 0) 2021 goto write_fail; 2022 goto out; 2023 } 2024 2025 len = write(c->wfd, buf, dlen); 2026 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2027 return 1; 2028 if (len <= 0) { 2029 write_fail: 2030 if (c->type != SSH_CHANNEL_OPEN) { 2031 debug2("channel %d: not open", c->self); 2032 chan_mark_dead(ssh, c); 2033 return -1; 2034 } else { 2035 chan_write_failed(ssh, c); 2036 } 2037 return -1; 2038 } 2039 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2040 if (tcgetattr(c->wfd, &tio) == 0 && 2041 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2042 /* 2043 * Simulate echo to reduce the impact of 2044 * traffic analysis. We need to match the 2045 * size of a SSH2_MSG_CHANNEL_DATA message 2046 * (4 byte channel id + buf) 2047 */ 2048 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2049 (r = sshpkt_send(ssh)) != 0) 2050 fatal_fr(r, "channel %i: ignore", c->self); 2051 } 2052 } 2053 if ((r = sshbuf_consume(c->output, len)) != 0) 2054 fatal_fr(r, "channel %i: consume", c->self); 2055 out: 2056 c->local_consumed += olen - sshbuf_len(c->output); 2057 2058 return 1; 2059 } 2060 2061 static int 2062 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2063 { 2064 int r; 2065 ssize_t len; 2066 2067 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2068 return 1; 2069 if (sshbuf_len(c->extended) == 0) 2070 return 1; 2071 2072 len = write(c->efd, sshbuf_ptr(c->extended), 2073 sshbuf_len(c->extended)); 2074 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2075 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2076 return 1; 2077 if (len <= 0) { 2078 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2079 channel_close_fd(ssh, c, &c->efd); 2080 } else { 2081 if ((r = sshbuf_consume(c->extended, len)) != 0) 2082 fatal_fr(r, "channel %i: consume", c->self); 2083 c->local_consumed += len; 2084 } 2085 return 1; 2086 } 2087 2088 static int 2089 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2090 { 2091 char buf[CHAN_RBUF]; 2092 int r; 2093 ssize_t len; 2094 2095 if ((c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2096 return 1; 2097 2098 len = read(c->efd, buf, sizeof(buf)); 2099 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2100 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2101 return 1; 2102 if (len <= 0) { 2103 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2104 channel_close_fd(ssh, c, &c->efd); 2105 } else if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2106 debug3("channel %d: discard efd", c->self); 2107 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2108 fatal_fr(r, "channel %i: append", c->self); 2109 return 1; 2110 } 2111 2112 static int 2113 channel_handle_efd(struct ssh *ssh, Channel *c) 2114 { 2115 if (c->efd == -1) 2116 return 1; 2117 2118 /** XXX handle drain efd, too */ 2119 2120 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2121 return channel_handle_efd_write(ssh, c); 2122 else if (c->extended_usage == CHAN_EXTENDED_READ || 2123 c->extended_usage == CHAN_EXTENDED_IGNORE) 2124 return channel_handle_efd_read(ssh, c); 2125 2126 return 1; 2127 } 2128 2129 static int 2130 channel_check_window(struct ssh *ssh, Channel *c) 2131 { 2132 int r; 2133 2134 if (c->type == SSH_CHANNEL_OPEN && 2135 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2136 ((c->local_window_max - c->local_window > 2137 c->local_maxpacket*3) || 2138 c->local_window < c->local_window_max/2) && 2139 c->local_consumed > 0) { 2140 if (!c->have_remote_id) 2141 fatal_f("channel %d: no remote id", c->self); 2142 if ((r = sshpkt_start(ssh, 2143 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2144 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2145 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2146 (r = sshpkt_send(ssh)) != 0) { 2147 fatal_fr(r, "channel %i", c->self); 2148 } 2149 debug2("channel %d: window %d sent adjust %d", c->self, 2150 c->local_window, c->local_consumed); 2151 c->local_window += c->local_consumed; 2152 c->local_consumed = 0; 2153 } 2154 return 1; 2155 } 2156 2157 static void 2158 channel_post_open(struct ssh *ssh, Channel *c) 2159 { 2160 channel_handle_rfd(ssh, c); 2161 channel_handle_wfd(ssh, c); 2162 channel_handle_efd(ssh, c); 2163 channel_check_window(ssh, c); 2164 } 2165 2166 static u_int 2167 read_mux(struct ssh *ssh, Channel *c, u_int need) 2168 { 2169 char buf[CHAN_RBUF]; 2170 ssize_t len; 2171 u_int rlen; 2172 int r; 2173 2174 if (sshbuf_len(c->input) < need) { 2175 rlen = need - sshbuf_len(c->input); 2176 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2177 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2178 return sshbuf_len(c->input); 2179 if (len <= 0) { 2180 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2181 c->self, c->rfd, len); 2182 chan_read_failed(ssh, c); 2183 return 0; 2184 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2185 fatal_fr(r, "channel %i: append", c->self); 2186 } 2187 return sshbuf_len(c->input); 2188 } 2189 2190 static void 2191 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2192 { 2193 u_int need; 2194 2195 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2196 return; 2197 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2198 return; 2199 if (c->mux_pause) 2200 return; 2201 2202 /* 2203 * Don't not read past the precise end of packets to 2204 * avoid disrupting fd passing. 2205 */ 2206 if (read_mux(ssh, c, 4) < 4) /* read header */ 2207 return; 2208 /* XXX sshbuf_peek_u32 */ 2209 need = PEEK_U32(sshbuf_ptr(c->input)); 2210 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2211 if (need > CHANNEL_MUX_MAX_PACKET) { 2212 debug2("channel %d: packet too big %u > %u", 2213 c->self, CHANNEL_MUX_MAX_PACKET, need); 2214 chan_rcvd_oclose(ssh, c); 2215 return; 2216 } 2217 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2218 return; 2219 if (c->mux_rcb(ssh, c) != 0) { 2220 debug("channel %d: mux_rcb failed", c->self); 2221 chan_mark_dead(ssh, c); 2222 return; 2223 } 2224 } 2225 2226 static void 2227 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2228 { 2229 ssize_t len; 2230 int r; 2231 2232 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2233 return; 2234 if (sshbuf_len(c->output) == 0) 2235 return; 2236 2237 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2238 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2239 return; 2240 if (len <= 0) { 2241 chan_mark_dead(ssh, c); 2242 return; 2243 } 2244 if ((r = sshbuf_consume(c->output, len)) != 0) 2245 fatal_fr(r, "channel %i: consume", c->self); 2246 } 2247 2248 static void 2249 channel_post_mux_client(struct ssh *ssh, Channel *c) 2250 { 2251 channel_post_mux_client_read(ssh, c); 2252 channel_post_mux_client_write(ssh, c); 2253 } 2254 2255 static void 2256 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2257 { 2258 Channel *nc; 2259 struct sockaddr_storage addr; 2260 socklen_t addrlen; 2261 int newsock; 2262 uid_t euid; 2263 gid_t egid; 2264 2265 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2266 return; 2267 2268 debug("multiplexing control connection"); 2269 2270 /* 2271 * Accept connection on control socket 2272 */ 2273 memset(&addr, 0, sizeof(addr)); 2274 addrlen = sizeof(addr); 2275 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2276 &addrlen)) == -1) { 2277 error_f("accept: %s", strerror(errno)); 2278 if (errno == EMFILE || errno == ENFILE) 2279 c->notbefore = monotime() + 1; 2280 return; 2281 } 2282 2283 if (getpeereid(newsock, &euid, &egid) == -1) { 2284 error_f("getpeereid failed: %s", strerror(errno)); 2285 close(newsock); 2286 return; 2287 } 2288 if ((euid != 0) && (getuid() != euid)) { 2289 error("multiplex uid mismatch: peer euid %u != uid %u", 2290 (u_int)euid, (u_int)getuid()); 2291 close(newsock); 2292 return; 2293 } 2294 nc = channel_new(ssh, "multiplex client", SSH_CHANNEL_MUX_CLIENT, 2295 newsock, newsock, -1, c->local_window_max, 2296 c->local_maxpacket, 0, "mux-control", 1); 2297 nc->mux_rcb = c->mux_rcb; 2298 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2299 /* establish state */ 2300 nc->mux_rcb(ssh, nc); 2301 /* mux state transitions must not elicit protocol messages */ 2302 nc->flags |= CHAN_LOCAL; 2303 } 2304 2305 static void 2306 channel_handler_init(struct ssh_channels *sc) 2307 { 2308 chan_fn **pre, **post; 2309 2310 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2311 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2312 fatal_f("allocation failed"); 2313 2314 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2315 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2316 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2317 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2318 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2319 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2320 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2321 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2322 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2323 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2324 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2325 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2326 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2327 2328 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2329 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2330 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2331 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2332 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2333 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2334 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2335 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2336 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2337 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2338 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2339 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2340 2341 sc->channel_pre = pre; 2342 sc->channel_post = post; 2343 } 2344 2345 /* gc dead channels */ 2346 static void 2347 channel_garbage_collect(struct ssh *ssh, Channel *c) 2348 { 2349 if (c == NULL) 2350 return; 2351 if (c->detach_user != NULL) { 2352 if (!chan_is_dead(ssh, c, c->detach_close)) 2353 return; 2354 2355 debug2("channel %d: gc: notify user", c->self); 2356 c->detach_user(ssh, c->self, NULL); 2357 /* if we still have a callback */ 2358 if (c->detach_user != NULL) 2359 return; 2360 debug2("channel %d: gc: user detached", c->self); 2361 } 2362 if (!chan_is_dead(ssh, c, 1)) 2363 return; 2364 debug2("channel %d: garbage collecting", c->self); 2365 channel_free(ssh, c); 2366 } 2367 2368 enum channel_table { CHAN_PRE, CHAN_POST }; 2369 2370 static void 2371 channel_handler(struct ssh *ssh, int table, 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 /* Try to keep IO going while rekeying */ 2387 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2388 continue; 2389 if (c->delayed) { 2390 if (table == CHAN_PRE) 2391 c->delayed = 0; 2392 else 2393 continue; 2394 } 2395 if (ftab[c->type] != NULL) { 2396 /* 2397 * Run handlers that are not paused. 2398 */ 2399 if (c->notbefore <= now) 2400 (*ftab[c->type])(ssh, c); 2401 else if (unpause_secs != NULL) { 2402 /* 2403 * Collect the time that the earliest 2404 * channel comes off pause. 2405 */ 2406 debug3_f("chan %d: skip for %d more " 2407 "seconds", c->self, 2408 (int)(c->notbefore - now)); 2409 if (*unpause_secs == 0 || 2410 (c->notbefore - now) < *unpause_secs) 2411 *unpause_secs = c->notbefore - now; 2412 } 2413 } 2414 channel_garbage_collect(ssh, c); 2415 } 2416 if (unpause_secs != NULL && *unpause_secs != 0) 2417 debug3_f("first channel unpauses in %d seconds", 2418 (int)*unpause_secs); 2419 } 2420 2421 /* 2422 * Create sockets before preparing IO. 2423 * This is necessary for things that need to happen after reading 2424 * the network-input but need to be completed before IO event setup, e.g. 2425 * because they may create new channels. 2426 */ 2427 static void 2428 channel_before_prepare_io(struct ssh *ssh) 2429 { 2430 struct ssh_channels *sc = ssh->chanctxt; 2431 Channel *c; 2432 u_int i, oalloc; 2433 2434 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2435 c = sc->channels[i]; 2436 if (c == NULL) 2437 continue; 2438 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2439 channel_before_prepare_io_rdynamic(ssh, c); 2440 } 2441 } 2442 2443 static void 2444 dump_channel_poll(const char *func, const char *what, Channel *c, 2445 u_int pollfd_offset, struct pollfd *pfd) 2446 { 2447 #ifdef DEBUG_CHANNEL_POLL 2448 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2449 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2450 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2451 c->rfd, c->wfd, c->efd, c->sock, 2452 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2453 c->io_want, c->io_ready, 2454 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2455 #endif 2456 } 2457 2458 /* Prepare pollfd entries for a single channel */ 2459 static void 2460 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2461 struct pollfd *pfd, u_int npfd) 2462 { 2463 u_int ev, p = *next_pollfd; 2464 2465 if (c == NULL) 2466 return; 2467 if (p + 4 > npfd) { 2468 /* Shouldn't happen */ 2469 fatal_f("channel %d: bad pfd offset %u (max %u)", 2470 c->self, p, npfd); 2471 } 2472 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2473 /* 2474 * prepare c->rfd 2475 * 2476 * This is a special case, since c->rfd might be the same as 2477 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2478 * IO too. 2479 */ 2480 if (c->rfd != -1) { 2481 ev = 0; 2482 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2483 ev |= POLLIN; 2484 /* rfd == wfd */ 2485 if (c->wfd == c->rfd) { 2486 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2487 ev |= POLLOUT; 2488 } 2489 /* rfd == efd */ 2490 if (c->efd == c->rfd) { 2491 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2492 ev |= POLLIN; 2493 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2494 ev |= POLLOUT; 2495 } 2496 /* rfd == sock */ 2497 if (c->sock == c->rfd) { 2498 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2499 ev |= POLLIN; 2500 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2501 ev |= POLLOUT; 2502 } 2503 /* Pack a pfd entry if any event armed for this fd */ 2504 if (ev != 0) { 2505 c->pfds[0] = p; 2506 pfd[p].fd = c->rfd; 2507 pfd[p].events = ev; 2508 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2509 p++; 2510 } 2511 } 2512 /* prepare c->wfd if wanting IO and not already handled above */ 2513 if (c->wfd != -1 && c->rfd != c->wfd) { 2514 ev = 0; 2515 if ((c->io_want & SSH_CHAN_IO_WFD)) 2516 ev |= POLLOUT; 2517 /* Pack a pfd entry if any event armed for this fd */ 2518 if (ev != 0) { 2519 c->pfds[1] = p; 2520 pfd[p].fd = c->wfd; 2521 pfd[p].events = ev; 2522 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2523 p++; 2524 } 2525 } 2526 /* prepare c->efd if wanting IO and not already handled above */ 2527 if (c->efd != -1 && c->rfd != c->efd) { 2528 ev = 0; 2529 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2530 ev |= POLLIN; 2531 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2532 ev |= POLLOUT; 2533 /* Pack a pfd entry if any event armed for this fd */ 2534 if (ev != 0) { 2535 c->pfds[2] = p; 2536 pfd[p].fd = c->efd; 2537 pfd[p].events = ev; 2538 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2539 p++; 2540 } 2541 } 2542 /* prepare c->sock if wanting IO and not already handled above */ 2543 if (c->sock != -1 && c->rfd != c->sock) { 2544 ev = 0; 2545 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2546 ev |= POLLIN; 2547 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2548 ev |= POLLOUT; 2549 /* Pack a pfd entry if any event armed for this fd */ 2550 if (ev != 0) { 2551 c->pfds[3] = p; 2552 pfd[p].fd = c->sock; 2553 pfd[p].events = 0; 2554 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2555 p++; 2556 } 2557 } 2558 *next_pollfd = p; 2559 } 2560 2561 /* * Allocate/prepare poll structure */ 2562 void 2563 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2564 u_int *npfd_activep, u_int npfd_reserved, time_t *minwait_secs) 2565 { 2566 struct ssh_channels *sc = ssh->chanctxt; 2567 u_int i, oalloc, p, npfd = npfd_reserved; 2568 2569 channel_before_prepare_io(ssh); /* might create a new channel */ 2570 /* clear out I/O flags from last poll */ 2571 for (i = 0; i < sc->channels_alloc; i++) { 2572 if (sc->channels[i] == NULL) 2573 continue; 2574 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2575 } 2576 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2577 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2578 fatal_f("too many channels"); /* shouldn't happen */ 2579 npfd += sc->channels_alloc * 4; 2580 if (npfd > *npfd_allocp) { 2581 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2582 npfd, sizeof(**pfdp)); 2583 *npfd_allocp = npfd; 2584 } 2585 *npfd_activep = npfd_reserved; 2586 oalloc = sc->channels_alloc; 2587 2588 channel_handler(ssh, CHAN_PRE, minwait_secs); 2589 2590 if (oalloc != sc->channels_alloc) { 2591 /* shouldn't happen */ 2592 fatal_f("channels_alloc changed during CHAN_PRE " 2593 "(was %u, now %u)", oalloc, sc->channels_alloc); 2594 } 2595 2596 /* Prepare pollfd */ 2597 p = npfd_reserved; 2598 for (i = 0; i < sc->channels_alloc; i++) 2599 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2600 *npfd_activep = p; 2601 } 2602 2603 static void 2604 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2605 const char *what, u_int revents_mask, u_int ready) 2606 { 2607 struct pollfd *pfd = &pfds[p]; 2608 2609 if (fd == -1) 2610 return; 2611 if (p == -1 || (u_int)p >= npfd) 2612 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2613 dump_channel_poll(__func__, what, c, p, pfd); 2614 if (pfd->fd != fd) { 2615 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2616 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2617 c->rfd, c->wfd, c->efd, c->sock); 2618 } 2619 if ((pfd->revents & POLLNVAL) != 0) { 2620 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2621 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2622 } 2623 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2624 c->io_ready |= ready & c->io_want; 2625 } 2626 2627 /* 2628 * After poll, perform any appropriate operations for channels which have 2629 * events pending. 2630 */ 2631 void 2632 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2633 { 2634 struct ssh_channels *sc = ssh->chanctxt; 2635 u_int i; 2636 int p; 2637 Channel *c; 2638 2639 #ifdef DEBUG_CHANNEL_POLL 2640 for (p = 0; p < (int)npfd; p++) { 2641 if (pfd[p].revents == 0) 2642 continue; 2643 debug_f("pfd[%u].fd %d rev 0x%04x", 2644 p, pfd[p].fd, pfd[p].revents); 2645 } 2646 #endif 2647 2648 /* Convert pollfd into c->io_ready */ 2649 for (i = 0; i < sc->channels_alloc; i++) { 2650 c = sc->channels[i]; 2651 if (c == NULL) 2652 continue; 2653 /* if rfd is shared with efd/sock then wfd should be too */ 2654 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2655 (c->rfd == c->efd || c->rfd == c->sock)) { 2656 /* Shouldn't happen */ 2657 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2658 c->self, c->rfd, c->wfd, c->efd, c->sock); 2659 } 2660 c->io_ready = 0; 2661 /* rfd, potentially shared with wfd, efd and sock */ 2662 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2663 fd_ready(c, p, pfd, npfd, c->rfd, 2664 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2665 if (c->rfd == c->wfd) { 2666 fd_ready(c, p, pfd, npfd, c->wfd, 2667 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2668 } 2669 if (c->rfd == c->efd) { 2670 fd_ready(c, p, pfd, npfd, c->efd, 2671 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2672 fd_ready(c, p, pfd, npfd, c->efd, 2673 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2674 } 2675 if (c->rfd == c->sock) { 2676 fd_ready(c, p, pfd, npfd, c->sock, 2677 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2678 fd_ready(c, p, pfd, npfd, c->sock, 2679 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2680 } 2681 dump_channel_poll(__func__, "rfd", c, p, pfd); 2682 } 2683 /* wfd */ 2684 if (c->wfd != -1 && c->wfd != c->rfd && 2685 (p = c->pfds[1]) != -1) { 2686 fd_ready(c, p, pfd, npfd, c->wfd, 2687 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2688 dump_channel_poll(__func__, "wfd", c, p, pfd); 2689 } 2690 /* efd */ 2691 if (c->efd != -1 && c->efd != c->rfd && 2692 (p = c->pfds[2]) != -1) { 2693 fd_ready(c, p, pfd, npfd, c->efd, 2694 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2695 fd_ready(c, p, pfd, npfd, c->efd, 2696 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2697 dump_channel_poll(__func__, "efd", c, p, pfd); 2698 } 2699 /* sock */ 2700 if (c->sock != -1 && c->sock != c->rfd && 2701 (p = c->pfds[3]) != -1) { 2702 fd_ready(c, p, pfd, npfd, c->sock, 2703 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2704 fd_ready(c, p, pfd, npfd, c->sock, 2705 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2706 dump_channel_poll(__func__, "sock", c, p, pfd); 2707 } 2708 } 2709 channel_handler(ssh, CHAN_POST, NULL); 2710 } 2711 2712 /* 2713 * Enqueue data for channels with open or draining c->input. 2714 */ 2715 static void 2716 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2717 { 2718 size_t len, plen; 2719 const u_char *pkt; 2720 int r; 2721 2722 if ((len = sshbuf_len(c->input)) == 0) { 2723 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2724 /* 2725 * input-buffer is empty and read-socket shutdown: 2726 * tell peer, that we will not send more data: 2727 * send IEOF. 2728 * hack for extended data: delay EOF if EFD still 2729 * in use. 2730 */ 2731 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2732 debug2("channel %d: " 2733 "ibuf_empty delayed efd %d/(%zu)", 2734 c->self, c->efd, sshbuf_len(c->extended)); 2735 else 2736 chan_ibuf_empty(ssh, c); 2737 } 2738 return; 2739 } 2740 2741 if (!c->have_remote_id) 2742 fatal_f("channel %d: no remote id", c->self); 2743 2744 if (c->datagram) { 2745 /* Check datagram will fit; drop if not */ 2746 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2747 fatal_fr(r, "channel %i: get datagram", c->self); 2748 /* 2749 * XXX this does tail-drop on the datagram queue which is 2750 * usually suboptimal compared to head-drop. Better to have 2751 * backpressure at read time? (i.e. read + discard) 2752 */ 2753 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2754 debug("channel %d: datagram too big", c->self); 2755 return; 2756 } 2757 /* Enqueue it */ 2758 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2759 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2760 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2761 (r = sshpkt_send(ssh)) != 0) 2762 fatal_fr(r, "channel %i: send datagram", c->self); 2763 c->remote_window -= plen; 2764 return; 2765 } 2766 2767 /* Enqueue packet for buffered data. */ 2768 if (len > c->remote_window) 2769 len = c->remote_window; 2770 if (len > c->remote_maxpacket) 2771 len = c->remote_maxpacket; 2772 if (len == 0) 2773 return; 2774 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2775 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2776 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2777 (r = sshpkt_send(ssh)) != 0) 2778 fatal_fr(r, "channel %i: send data", c->self); 2779 if ((r = sshbuf_consume(c->input, len)) != 0) 2780 fatal_fr(r, "channel %i: consume", c->self); 2781 c->remote_window -= len; 2782 } 2783 2784 /* 2785 * Enqueue data for channels with open c->extended in read mode. 2786 */ 2787 static void 2788 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2789 { 2790 size_t len; 2791 int r; 2792 2793 if ((len = sshbuf_len(c->extended)) == 0) 2794 return; 2795 2796 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2797 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2798 if (len > c->remote_window) 2799 len = c->remote_window; 2800 if (len > c->remote_maxpacket) 2801 len = c->remote_maxpacket; 2802 if (len == 0) 2803 return; 2804 if (!c->have_remote_id) 2805 fatal_f("channel %d: no remote id", c->self); 2806 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2807 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2808 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2809 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2810 (r = sshpkt_send(ssh)) != 0) 2811 fatal_fr(r, "channel %i: data", c->self); 2812 if ((r = sshbuf_consume(c->extended, len)) != 0) 2813 fatal_fr(r, "channel %i: consume", c->self); 2814 c->remote_window -= len; 2815 debug2("channel %d: sent ext data %zu", c->self, len); 2816 } 2817 2818 /* If there is data to send to the connection, enqueue some of it now. */ 2819 void 2820 channel_output_poll(struct ssh *ssh) 2821 { 2822 struct ssh_channels *sc = ssh->chanctxt; 2823 Channel *c; 2824 u_int i; 2825 2826 for (i = 0; i < sc->channels_alloc; i++) { 2827 c = sc->channels[i]; 2828 if (c == NULL) 2829 continue; 2830 2831 /* 2832 * We are only interested in channels that can have buffered 2833 * incoming data. 2834 */ 2835 if (c->type != SSH_CHANNEL_OPEN) 2836 continue; 2837 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2838 /* XXX is this true? */ 2839 debug3("channel %d: will not send data after close", 2840 c->self); 2841 continue; 2842 } 2843 2844 /* Get the amount of buffered data for this channel. */ 2845 if (c->istate == CHAN_INPUT_OPEN || 2846 c->istate == CHAN_INPUT_WAIT_DRAIN) 2847 channel_output_poll_input_open(ssh, c); 2848 /* Send extended data, i.e. stderr */ 2849 if (!(c->flags & CHAN_EOF_SENT) && 2850 c->extended_usage == CHAN_EXTENDED_READ) 2851 channel_output_poll_extended_read(ssh, c); 2852 } 2853 } 2854 2855 /* -- mux proxy support */ 2856 2857 /* 2858 * When multiplexing channel messages for mux clients we have to deal 2859 * with downstream messages from the mux client and upstream messages 2860 * from the ssh server: 2861 * 1) Handling downstream messages is straightforward and happens 2862 * in channel_proxy_downstream(): 2863 * - We forward all messages (mostly) unmodified to the server. 2864 * - However, in order to route messages from upstream to the correct 2865 * downstream client, we have to replace the channel IDs used by the 2866 * mux clients with a unique channel ID because the mux clients might 2867 * use conflicting channel IDs. 2868 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 2869 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 2870 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 2871 * with the newly allocated channel ID. 2872 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 2873 * channels and processed by channel_proxy_upstream(). The local channel ID 2874 * is then translated back to the original mux client ID. 2875 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 2876 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 2877 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 2878 * downstream mux client are removed. 2879 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 2880 * requires more work, because they are not addressed to a specific 2881 * channel. E.g. client_request_forwarded_tcpip() needs to figure 2882 * out whether the request is addressed to the local client or a 2883 * specific downstream client based on the listen-address/port. 2884 * 6) Agent and X11-Forwarding have a similar problem and are currently 2885 * not supported as the matching session/channel cannot be identified 2886 * easily. 2887 */ 2888 2889 /* 2890 * receive packets from downstream mux clients: 2891 * channel callback fired on read from mux client, creates 2892 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 2893 * on channel creation. 2894 */ 2895 int 2896 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 2897 { 2898 Channel *c = NULL; 2899 struct sshbuf *original = NULL, *modified = NULL; 2900 const u_char *cp; 2901 char *ctype = NULL, *listen_host = NULL; 2902 u_char type; 2903 size_t have; 2904 int ret = -1, r; 2905 u_int id, remote_id, listen_port; 2906 2907 /* sshbuf_dump(downstream->input, stderr); */ 2908 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 2909 != 0) { 2910 error_fr(r, "parse"); 2911 return -1; 2912 } 2913 if (have < 2) { 2914 error_f("short message"); 2915 return -1; 2916 } 2917 type = cp[1]; 2918 /* skip padlen + type */ 2919 cp += 2; 2920 have -= 2; 2921 if (ssh_packet_log_type(type)) 2922 debug3_f("channel %u: down->up: type %u", 2923 downstream->self, type); 2924 2925 switch (type) { 2926 case SSH2_MSG_CHANNEL_OPEN: 2927 if ((original = sshbuf_from(cp, have)) == NULL || 2928 (modified = sshbuf_new()) == NULL) { 2929 error_f("alloc"); 2930 goto out; 2931 } 2932 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 2933 (r = sshbuf_get_u32(original, &id)) != 0) { 2934 error_fr(r, "parse"); 2935 goto out; 2936 } 2937 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2938 -1, -1, -1, 0, 0, 0, ctype, 1); 2939 c->mux_ctx = downstream; /* point to mux client */ 2940 c->mux_downstream_id = id; /* original downstream id */ 2941 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 2942 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2943 (r = sshbuf_putb(modified, original)) != 0) { 2944 error_fr(r, "compose"); 2945 channel_free(ssh, c); 2946 goto out; 2947 } 2948 break; 2949 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2950 /* 2951 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 2952 * need to parse 'remote_id' instead of 'ctype'. 2953 */ 2954 if ((original = sshbuf_from(cp, have)) == NULL || 2955 (modified = sshbuf_new()) == NULL) { 2956 error_f("alloc"); 2957 goto out; 2958 } 2959 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 2960 (r = sshbuf_get_u32(original, &id)) != 0) { 2961 error_fr(r, "parse"); 2962 goto out; 2963 } 2964 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2965 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 2966 c->mux_ctx = downstream; /* point to mux client */ 2967 c->mux_downstream_id = id; 2968 c->remote_id = remote_id; 2969 c->have_remote_id = 1; 2970 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 2971 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2972 (r = sshbuf_putb(modified, original)) != 0) { 2973 error_fr(r, "compose"); 2974 channel_free(ssh, c); 2975 goto out; 2976 } 2977 break; 2978 case SSH2_MSG_GLOBAL_REQUEST: 2979 if ((original = sshbuf_from(cp, have)) == NULL) { 2980 error_f("alloc"); 2981 goto out; 2982 } 2983 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 2984 error_fr(r, "parse"); 2985 goto out; 2986 } 2987 if (strcmp(ctype, "tcpip-forward") != 0) { 2988 error_f("unsupported request %s", ctype); 2989 goto out; 2990 } 2991 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 2992 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 2993 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 2994 error_fr(r, "parse"); 2995 goto out; 2996 } 2997 if (listen_port > 65535) { 2998 error_f("tcpip-forward for %s: bad port %u", 2999 listen_host, listen_port); 3000 goto out; 3001 } 3002 /* Record that connection to this host/port is permitted. */ 3003 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 3004 listen_host, NULL, (int)listen_port, downstream); 3005 listen_host = NULL; 3006 break; 3007 case SSH2_MSG_CHANNEL_CLOSE: 3008 if (have < 4) 3009 break; 3010 remote_id = PEEK_U32(cp); 3011 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3012 if (c->flags & CHAN_CLOSE_RCVD) 3013 channel_free(ssh, c); 3014 else 3015 c->flags |= CHAN_CLOSE_SENT; 3016 } 3017 break; 3018 } 3019 if (modified) { 3020 if ((r = sshpkt_start(ssh, type)) != 0 || 3021 (r = sshpkt_putb(ssh, modified)) != 0 || 3022 (r = sshpkt_send(ssh)) != 0) { 3023 error_fr(r, "send"); 3024 goto out; 3025 } 3026 } else { 3027 if ((r = sshpkt_start(ssh, type)) != 0 || 3028 (r = sshpkt_put(ssh, cp, have)) != 0 || 3029 (r = sshpkt_send(ssh)) != 0) { 3030 error_fr(r, "send"); 3031 goto out; 3032 } 3033 } 3034 ret = 0; 3035 out: 3036 free(ctype); 3037 free(listen_host); 3038 sshbuf_free(original); 3039 sshbuf_free(modified); 3040 return ret; 3041 } 3042 3043 /* 3044 * receive packets from upstream server and de-multiplex packets 3045 * to correct downstream: 3046 * implemented as a helper for channel input handlers, 3047 * replaces local (proxy) channel ID with downstream channel ID. 3048 */ 3049 int 3050 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3051 { 3052 struct sshbuf *b = NULL; 3053 Channel *downstream; 3054 const u_char *cp = NULL; 3055 size_t len; 3056 int r; 3057 3058 /* 3059 * When receiving packets from the peer we need to check whether we 3060 * need to forward the packets to the mux client. In this case we 3061 * restore the original channel id and keep track of CLOSE messages, 3062 * so we can cleanup the channel. 3063 */ 3064 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3065 return 0; 3066 if ((downstream = c->mux_ctx) == NULL) 3067 return 0; 3068 switch (type) { 3069 case SSH2_MSG_CHANNEL_CLOSE: 3070 case SSH2_MSG_CHANNEL_DATA: 3071 case SSH2_MSG_CHANNEL_EOF: 3072 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3073 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3074 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3075 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3076 case SSH2_MSG_CHANNEL_SUCCESS: 3077 case SSH2_MSG_CHANNEL_FAILURE: 3078 case SSH2_MSG_CHANNEL_REQUEST: 3079 break; 3080 default: 3081 debug2_f("channel %u: unsupported type %u", c->self, type); 3082 return 0; 3083 } 3084 if ((b = sshbuf_new()) == NULL) { 3085 error_f("alloc reply"); 3086 goto out; 3087 } 3088 /* get remaining payload (after id) */ 3089 cp = sshpkt_ptr(ssh, &len); 3090 if (cp == NULL) { 3091 error_f("no packet"); 3092 goto out; 3093 } 3094 /* translate id and send to muxclient */ 3095 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3096 (r = sshbuf_put_u8(b, type)) != 0 || 3097 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3098 (r = sshbuf_put(b, cp, len)) != 0 || 3099 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3100 error_fr(r, "compose muxclient"); 3101 goto out; 3102 } 3103 /* sshbuf_dump(b, stderr); */ 3104 if (ssh_packet_log_type(type)) 3105 debug3_f("channel %u: up->down: type %u", c->self, type); 3106 out: 3107 /* update state */ 3108 switch (type) { 3109 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3110 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3111 if (cp && len > 4) { 3112 c->remote_id = PEEK_U32(cp); 3113 c->have_remote_id = 1; 3114 } 3115 break; 3116 case SSH2_MSG_CHANNEL_CLOSE: 3117 if (c->flags & CHAN_CLOSE_SENT) 3118 channel_free(ssh, c); 3119 else 3120 c->flags |= CHAN_CLOSE_RCVD; 3121 break; 3122 } 3123 sshbuf_free(b); 3124 return 1; 3125 } 3126 3127 /* -- protocol input */ 3128 3129 /* Parse a channel ID from the current packet */ 3130 static int 3131 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3132 { 3133 u_int32_t id; 3134 int r; 3135 3136 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3137 error_r(r, "%s: parse id", where); 3138 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3139 } 3140 if (id > INT_MAX) { 3141 error_r(r, "%s: bad channel id %u", where, id); 3142 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3143 } 3144 return (int)id; 3145 } 3146 3147 /* Lookup a channel from an ID in the current packet */ 3148 static Channel * 3149 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3150 { 3151 int id = channel_parse_id(ssh, where, what); 3152 Channel *c; 3153 3154 if ((c = channel_lookup(ssh, id)) == NULL) { 3155 ssh_packet_disconnect(ssh, 3156 "%s packet referred to nonexistent channel %d", what, id); 3157 } 3158 return c; 3159 } 3160 3161 int 3162 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3163 { 3164 const u_char *data; 3165 size_t data_len, win_len; 3166 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3167 int r; 3168 3169 if (channel_proxy_upstream(c, type, seq, ssh)) 3170 return 0; 3171 3172 /* Ignore any data for non-open channels (might happen on close) */ 3173 if (c->type != SSH_CHANNEL_OPEN && 3174 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3175 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3176 c->type != SSH_CHANNEL_X11_OPEN) 3177 return 0; 3178 3179 /* Get the data. */ 3180 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3181 (r = sshpkt_get_end(ssh)) != 0) 3182 fatal_fr(r, "channel %i: get data", c->self); 3183 3184 win_len = data_len; 3185 if (c->datagram) 3186 win_len += 4; /* string length header */ 3187 3188 /* 3189 * The sending side reduces its window as it sends data, so we 3190 * must 'fake' consumption of the data in order to ensure that window 3191 * updates are sent back. Otherwise the connection might deadlock. 3192 */ 3193 if (c->ostate != CHAN_OUTPUT_OPEN) { 3194 c->local_window -= win_len; 3195 c->local_consumed += win_len; 3196 return 0; 3197 } 3198 3199 if (win_len > c->local_maxpacket) { 3200 logit("channel %d: rcvd big packet %zu, maxpack %u", 3201 c->self, win_len, c->local_maxpacket); 3202 return 0; 3203 } 3204 if (win_len > c->local_window) { 3205 logit("channel %d: rcvd too much data %zu, win %u", 3206 c->self, win_len, c->local_window); 3207 return 0; 3208 } 3209 c->local_window -= win_len; 3210 3211 if (c->datagram) { 3212 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3213 fatal_fr(r, "channel %i: append datagram", c->self); 3214 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3215 fatal_fr(r, "channel %i: append data", c->self); 3216 3217 return 0; 3218 } 3219 3220 int 3221 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3222 { 3223 const u_char *data; 3224 size_t data_len; 3225 u_int32_t tcode; 3226 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3227 int r; 3228 3229 if (channel_proxy_upstream(c, type, seq, ssh)) 3230 return 0; 3231 if (c->type != SSH_CHANNEL_OPEN) { 3232 logit("channel %d: ext data for non open", c->self); 3233 return 0; 3234 } 3235 if (c->flags & CHAN_EOF_RCVD) { 3236 if (ssh->compat & SSH_BUG_EXTEOF) 3237 debug("channel %d: accepting ext data after eof", 3238 c->self); 3239 else 3240 ssh_packet_disconnect(ssh, "Received extended_data " 3241 "after EOF on channel %d.", c->self); 3242 } 3243 3244 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3245 error_fr(r, "parse tcode"); 3246 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3247 } 3248 if (c->efd == -1 || 3249 c->extended_usage != CHAN_EXTENDED_WRITE || 3250 tcode != SSH2_EXTENDED_DATA_STDERR) { 3251 logit("channel %d: bad ext data", c->self); 3252 return 0; 3253 } 3254 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3255 (r = sshpkt_get_end(ssh)) != 0) { 3256 error_fr(r, "parse data"); 3257 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3258 } 3259 3260 if (data_len > c->local_window) { 3261 logit("channel %d: rcvd too much extended_data %zu, win %u", 3262 c->self, data_len, c->local_window); 3263 return 0; 3264 } 3265 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3266 /* XXX sshpkt_getb? */ 3267 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3268 error_fr(r, "append"); 3269 c->local_window -= data_len; 3270 return 0; 3271 } 3272 3273 int 3274 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3275 { 3276 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3277 int r; 3278 3279 if ((r = sshpkt_get_end(ssh)) != 0) { 3280 error_fr(r, "parse data"); 3281 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3282 } 3283 3284 if (channel_proxy_upstream(c, type, seq, ssh)) 3285 return 0; 3286 chan_rcvd_ieof(ssh, c); 3287 3288 /* XXX force input close */ 3289 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3290 debug("channel %d: FORCE input drain", c->self); 3291 c->istate = CHAN_INPUT_WAIT_DRAIN; 3292 if (sshbuf_len(c->input) == 0) 3293 chan_ibuf_empty(ssh, c); 3294 } 3295 return 0; 3296 } 3297 3298 int 3299 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3300 { 3301 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3302 int r; 3303 3304 if (channel_proxy_upstream(c, type, seq, ssh)) 3305 return 0; 3306 if ((r = sshpkt_get_end(ssh)) != 0) { 3307 error_fr(r, "parse data"); 3308 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3309 } 3310 chan_rcvd_oclose(ssh, c); 3311 return 0; 3312 } 3313 3314 int 3315 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3316 { 3317 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3318 u_int32_t remote_window, remote_maxpacket; 3319 int r; 3320 3321 if (channel_proxy_upstream(c, type, seq, ssh)) 3322 return 0; 3323 if (c->type != SSH_CHANNEL_OPENING) 3324 ssh_packet_disconnect(ssh, "Received open confirmation for " 3325 "non-opening channel %d.", c->self); 3326 /* 3327 * Record the remote channel number and mark that the channel 3328 * is now open. 3329 */ 3330 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3331 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3332 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3333 (r = sshpkt_get_end(ssh)) != 0) { 3334 error_fr(r, "window/maxpacket"); 3335 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3336 } 3337 3338 c->have_remote_id = 1; 3339 c->remote_window = remote_window; 3340 c->remote_maxpacket = remote_maxpacket; 3341 c->type = SSH_CHANNEL_OPEN; 3342 if (c->open_confirm) { 3343 debug2_f("channel %d: callback start", c->self); 3344 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3345 debug2_f("channel %d: callback done", c->self); 3346 } 3347 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3348 c->remote_window, c->remote_maxpacket); 3349 return 0; 3350 } 3351 3352 static char * 3353 reason2txt(int reason) 3354 { 3355 switch (reason) { 3356 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3357 return "administratively prohibited"; 3358 case SSH2_OPEN_CONNECT_FAILED: 3359 return "connect failed"; 3360 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3361 return "unknown channel type"; 3362 case SSH2_OPEN_RESOURCE_SHORTAGE: 3363 return "resource shortage"; 3364 } 3365 return "unknown reason"; 3366 } 3367 3368 int 3369 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3370 { 3371 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3372 u_int32_t reason; 3373 char *msg = NULL; 3374 int r; 3375 3376 if (channel_proxy_upstream(c, type, seq, ssh)) 3377 return 0; 3378 if (c->type != SSH_CHANNEL_OPENING) 3379 ssh_packet_disconnect(ssh, "Received open failure for " 3380 "non-opening channel %d.", c->self); 3381 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3382 error_fr(r, "parse reason"); 3383 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3384 } 3385 /* skip language */ 3386 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3387 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3388 (r = sshpkt_get_end(ssh)) != 0) { 3389 error_fr(r, "parse msg/lang"); 3390 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3391 } 3392 logit("channel %d: open failed: %s%s%s", c->self, 3393 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3394 free(msg); 3395 if (c->open_confirm) { 3396 debug2_f("channel %d: callback start", c->self); 3397 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3398 debug2_f("channel %d: callback done", c->self); 3399 } 3400 /* Schedule the channel for cleanup/deletion. */ 3401 chan_mark_dead(ssh, c); 3402 return 0; 3403 } 3404 3405 int 3406 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3407 { 3408 int id = channel_parse_id(ssh, __func__, "window adjust"); 3409 Channel *c; 3410 u_int32_t adjust; 3411 u_int new_rwin; 3412 int r; 3413 3414 if ((c = channel_lookup(ssh, id)) == NULL) { 3415 logit("Received window adjust for non-open channel %d.", id); 3416 return 0; 3417 } 3418 3419 if (channel_proxy_upstream(c, type, seq, ssh)) 3420 return 0; 3421 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3422 (r = sshpkt_get_end(ssh)) != 0) { 3423 error_fr(r, "parse adjust"); 3424 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3425 } 3426 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3427 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3428 fatal("channel %d: adjust %u overflows remote window %u", 3429 c->self, adjust, c->remote_window); 3430 } 3431 c->remote_window = new_rwin; 3432 return 0; 3433 } 3434 3435 int 3436 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3437 { 3438 int id = channel_parse_id(ssh, __func__, "status confirm"); 3439 Channel *c; 3440 struct channel_confirm *cc; 3441 3442 /* Reset keepalive timeout */ 3443 ssh_packet_set_alive_timeouts(ssh, 0); 3444 3445 debug2_f("type %d id %d", type, id); 3446 3447 if ((c = channel_lookup(ssh, id)) == NULL) { 3448 logit_f("%d: unknown", id); 3449 return 0; 3450 } 3451 if (channel_proxy_upstream(c, type, seq, ssh)) 3452 return 0; 3453 if (sshpkt_get_end(ssh) != 0) 3454 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3455 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3456 return 0; 3457 cc->cb(ssh, type, c, cc->ctx); 3458 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3459 freezero(cc, sizeof(*cc)); 3460 return 0; 3461 } 3462 3463 /* -- tcp forwarding */ 3464 3465 void 3466 channel_set_af(struct ssh *ssh, int af) 3467 { 3468 ssh->chanctxt->IPv4or6 = af; 3469 } 3470 3471 3472 /* 3473 * Determine whether or not a port forward listens to loopback, the 3474 * specified address or wildcard. On the client, a specified bind 3475 * address will always override gateway_ports. On the server, a 3476 * gateway_ports of 1 (``yes'') will override the client's specification 3477 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3478 * will bind to whatever address the client asked for. 3479 * 3480 * Special-case listen_addrs are: 3481 * 3482 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3483 * "" (empty string), "*" -> wildcard v4/v6 3484 * "localhost" -> loopback v4/v6 3485 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3486 */ 3487 static const char * 3488 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3489 int is_client, struct ForwardOptions *fwd_opts) 3490 { 3491 const char *addr = NULL; 3492 int wildcard = 0; 3493 3494 if (listen_addr == NULL) { 3495 /* No address specified: default to gateway_ports setting */ 3496 if (fwd_opts->gateway_ports) 3497 wildcard = 1; 3498 } else if (fwd_opts->gateway_ports || is_client) { 3499 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3500 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3501 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3502 (!is_client && fwd_opts->gateway_ports == 1)) { 3503 wildcard = 1; 3504 /* 3505 * Notify client if they requested a specific listen 3506 * address and it was overridden. 3507 */ 3508 if (*listen_addr != '\0' && 3509 strcmp(listen_addr, "0.0.0.0") != 0 && 3510 strcmp(listen_addr, "*") != 0) { 3511 ssh_packet_send_debug(ssh, 3512 "Forwarding listen address " 3513 "\"%s\" overridden by server " 3514 "GatewayPorts", listen_addr); 3515 } 3516 } else if (strcmp(listen_addr, "localhost") != 0 || 3517 strcmp(listen_addr, "127.0.0.1") == 0 || 3518 strcmp(listen_addr, "::1") == 0) { 3519 /* 3520 * Accept explicit localhost address when 3521 * GatewayPorts=yes. The "localhost" hostname is 3522 * deliberately skipped here so it will listen on all 3523 * available local address families. 3524 */ 3525 addr = listen_addr; 3526 } 3527 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3528 strcmp(listen_addr, "::1") == 0) { 3529 /* 3530 * If a specific IPv4/IPv6 localhost address has been 3531 * requested then accept it even if gateway_ports is in 3532 * effect. This allows the client to prefer IPv4 or IPv6. 3533 */ 3534 addr = listen_addr; 3535 } 3536 if (wildcardp != NULL) 3537 *wildcardp = wildcard; 3538 return addr; 3539 } 3540 3541 static int 3542 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3543 struct Forward *fwd, int *allocated_listen_port, 3544 struct ForwardOptions *fwd_opts) 3545 { 3546 Channel *c; 3547 int sock, r, success = 0, wildcard = 0, is_client; 3548 struct addrinfo hints, *ai, *aitop; 3549 const char *host, *addr; 3550 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3551 in_port_t *lport_p; 3552 3553 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3554 3555 if (is_client && fwd->connect_path != NULL) { 3556 host = fwd->connect_path; 3557 } else { 3558 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3559 fwd->listen_host : fwd->connect_host; 3560 if (host == NULL) { 3561 error("No forward host name."); 3562 return 0; 3563 } 3564 if (strlen(host) >= NI_MAXHOST) { 3565 error("Forward host name too long."); 3566 return 0; 3567 } 3568 } 3569 3570 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3571 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3572 is_client, fwd_opts); 3573 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3574 (addr == NULL) ? "NULL" : addr); 3575 3576 /* 3577 * getaddrinfo returns a loopback address if the hostname is 3578 * set to NULL and hints.ai_flags is not AI_PASSIVE 3579 */ 3580 memset(&hints, 0, sizeof(hints)); 3581 hints.ai_family = ssh->chanctxt->IPv4or6; 3582 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3583 hints.ai_socktype = SOCK_STREAM; 3584 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3585 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3586 if (addr == NULL) { 3587 /* This really shouldn't happen */ 3588 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3589 ssh_gai_strerror(r)); 3590 } else { 3591 error_f("getaddrinfo(%.64s): %s", addr, 3592 ssh_gai_strerror(r)); 3593 } 3594 return 0; 3595 } 3596 if (allocated_listen_port != NULL) 3597 *allocated_listen_port = 0; 3598 for (ai = aitop; ai; ai = ai->ai_next) { 3599 switch (ai->ai_family) { 3600 case AF_INET: 3601 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3602 sin_port; 3603 break; 3604 case AF_INET6: 3605 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3606 sin6_port; 3607 break; 3608 default: 3609 continue; 3610 } 3611 /* 3612 * If allocating a port for -R forwards, then use the 3613 * same port for all address families. 3614 */ 3615 if (type == SSH_CHANNEL_RPORT_LISTENER && 3616 fwd->listen_port == 0 && allocated_listen_port != NULL && 3617 *allocated_listen_port > 0) 3618 *lport_p = htons(*allocated_listen_port); 3619 3620 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3621 strport, sizeof(strport), 3622 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3623 error_f("getnameinfo failed"); 3624 continue; 3625 } 3626 /* Create a port to listen for the host. */ 3627 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3628 if (sock == -1) { 3629 /* this is no error since kernel may not support ipv6 */ 3630 verbose("socket [%s]:%s: %.100s", ntop, strport, 3631 strerror(errno)); 3632 continue; 3633 } 3634 3635 set_reuseaddr(sock); 3636 3637 debug("Local forwarding listening on %s port %s.", 3638 ntop, strport); 3639 3640 /* Bind the socket to the address. */ 3641 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3642 /* 3643 * address can be in if use ipv6 address is 3644 * already bound 3645 */ 3646 verbose("bind [%s]:%s: %.100s", 3647 ntop, strport, strerror(errno)); 3648 close(sock); 3649 continue; 3650 } 3651 /* Start listening for connections on the socket. */ 3652 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3653 error("listen [%s]:%s: %.100s", ntop, strport, 3654 strerror(errno)); 3655 close(sock); 3656 continue; 3657 } 3658 3659 /* 3660 * fwd->listen_port == 0 requests a dynamically allocated port - 3661 * record what we got. 3662 */ 3663 if (type == SSH_CHANNEL_RPORT_LISTENER && 3664 fwd->listen_port == 0 && 3665 allocated_listen_port != NULL && 3666 *allocated_listen_port == 0) { 3667 *allocated_listen_port = get_local_port(sock); 3668 debug("Allocated listen port %d", 3669 *allocated_listen_port); 3670 } 3671 3672 /* Allocate a channel number for the socket. */ 3673 c = channel_new(ssh, "port listener", type, sock, sock, -1, 3674 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3675 0, "port listener", 1); 3676 c->path = xstrdup(host); 3677 c->host_port = fwd->connect_port; 3678 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3679 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3680 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3681 c->listening_port = *allocated_listen_port; 3682 else 3683 c->listening_port = fwd->listen_port; 3684 success = 1; 3685 } 3686 if (success == 0) 3687 error_f("cannot listen to port: %d", fwd->listen_port); 3688 freeaddrinfo(aitop); 3689 return success; 3690 } 3691 3692 static int 3693 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3694 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3695 { 3696 struct sockaddr_un sunaddr; 3697 const char *path; 3698 Channel *c; 3699 int port, sock; 3700 mode_t omask; 3701 3702 switch (type) { 3703 case SSH_CHANNEL_UNIX_LISTENER: 3704 if (fwd->connect_path != NULL) { 3705 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3706 error("Local connecting path too long: %s", 3707 fwd->connect_path); 3708 return 0; 3709 } 3710 path = fwd->connect_path; 3711 port = PORT_STREAMLOCAL; 3712 } else { 3713 if (fwd->connect_host == NULL) { 3714 error("No forward host name."); 3715 return 0; 3716 } 3717 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3718 error("Forward host name too long."); 3719 return 0; 3720 } 3721 path = fwd->connect_host; 3722 port = fwd->connect_port; 3723 } 3724 break; 3725 case SSH_CHANNEL_RUNIX_LISTENER: 3726 path = fwd->listen_path; 3727 port = PORT_STREAMLOCAL; 3728 break; 3729 default: 3730 error_f("unexpected channel type %d", type); 3731 return 0; 3732 } 3733 3734 if (fwd->listen_path == NULL) { 3735 error("No forward path name."); 3736 return 0; 3737 } 3738 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3739 error("Local listening path too long: %s", fwd->listen_path); 3740 return 0; 3741 } 3742 3743 debug3_f("type %d path %s", type, fwd->listen_path); 3744 3745 /* Start a Unix domain listener. */ 3746 omask = umask(fwd_opts->streamlocal_bind_mask); 3747 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3748 fwd_opts->streamlocal_bind_unlink); 3749 umask(omask); 3750 if (sock < 0) 3751 return 0; 3752 3753 debug("Local forwarding listening on path %s.", fwd->listen_path); 3754 3755 /* Allocate a channel number for the socket. */ 3756 c = channel_new(ssh, "unix listener", type, sock, sock, -1, 3757 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3758 0, "unix listener", 1); 3759 c->path = xstrdup(path); 3760 c->host_port = port; 3761 c->listening_port = PORT_STREAMLOCAL; 3762 c->listening_addr = xstrdup(fwd->listen_path); 3763 return 1; 3764 } 3765 3766 static int 3767 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3768 const char *host, u_short port) 3769 { 3770 u_int i; 3771 int found = 0; 3772 3773 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3774 Channel *c = ssh->chanctxt->channels[i]; 3775 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3776 continue; 3777 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3778 debug2_f("close channel %d", i); 3779 channel_free(ssh, c); 3780 found = 1; 3781 } 3782 } 3783 3784 return found; 3785 } 3786 3787 static int 3788 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3789 { 3790 u_int i; 3791 int found = 0; 3792 3793 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3794 Channel *c = ssh->chanctxt->channels[i]; 3795 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3796 continue; 3797 if (c->path == NULL) 3798 continue; 3799 if (strcmp(c->path, path) == 0) { 3800 debug2_f("close channel %d", i); 3801 channel_free(ssh, c); 3802 found = 1; 3803 } 3804 } 3805 3806 return found; 3807 } 3808 3809 int 3810 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3811 { 3812 if (fwd->listen_path != NULL) { 3813 return channel_cancel_rport_listener_streamlocal(ssh, 3814 fwd->listen_path); 3815 } else { 3816 return channel_cancel_rport_listener_tcpip(ssh, 3817 fwd->listen_host, fwd->listen_port); 3818 } 3819 } 3820 3821 static int 3822 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 3823 const char *lhost, u_short lport, int cport, 3824 struct ForwardOptions *fwd_opts) 3825 { 3826 u_int i; 3827 int found = 0; 3828 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 3829 3830 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3831 Channel *c = ssh->chanctxt->channels[i]; 3832 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 3833 continue; 3834 if (c->listening_port != lport) 3835 continue; 3836 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 3837 /* skip dynamic forwardings */ 3838 if (c->host_port == 0) 3839 continue; 3840 } else { 3841 if (c->host_port != cport) 3842 continue; 3843 } 3844 if ((c->listening_addr == NULL && addr != NULL) || 3845 (c->listening_addr != NULL && addr == NULL)) 3846 continue; 3847 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 3848 debug2_f("close channel %d", i); 3849 channel_free(ssh, c); 3850 found = 1; 3851 } 3852 } 3853 3854 return found; 3855 } 3856 3857 static int 3858 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 3859 { 3860 u_int i; 3861 int found = 0; 3862 3863 if (path == NULL) { 3864 error_f("no path specified."); 3865 return 0; 3866 } 3867 3868 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3869 Channel *c = ssh->chanctxt->channels[i]; 3870 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 3871 continue; 3872 if (c->listening_addr == NULL) 3873 continue; 3874 if (strcmp(c->listening_addr, path) == 0) { 3875 debug2_f("close channel %d", i); 3876 channel_free(ssh, c); 3877 found = 1; 3878 } 3879 } 3880 3881 return found; 3882 } 3883 3884 int 3885 channel_cancel_lport_listener(struct ssh *ssh, 3886 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 3887 { 3888 if (fwd->listen_path != NULL) { 3889 return channel_cancel_lport_listener_streamlocal(ssh, 3890 fwd->listen_path); 3891 } else { 3892 return channel_cancel_lport_listener_tcpip(ssh, 3893 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 3894 } 3895 } 3896 3897 /* protocol local port fwd, used by ssh */ 3898 int 3899 channel_setup_local_fwd_listener(struct ssh *ssh, 3900 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3901 { 3902 if (fwd->listen_path != NULL) { 3903 return channel_setup_fwd_listener_streamlocal(ssh, 3904 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 3905 } else { 3906 return channel_setup_fwd_listener_tcpip(ssh, 3907 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 3908 } 3909 } 3910 3911 /* Matches a remote forwarding permission against a requested forwarding */ 3912 static int 3913 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 3914 { 3915 int ret; 3916 char *lhost; 3917 3918 /* XXX add ACLs for streamlocal */ 3919 if (fwd->listen_path != NULL) 3920 return 1; 3921 3922 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 3923 return 0; 3924 3925 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 3926 allowed_open->listen_port != fwd->listen_port) 3927 return 0; 3928 3929 /* Match hostnames case-insensitively */ 3930 lhost = xstrdup(fwd->listen_host); 3931 lowercase(lhost); 3932 ret = match_pattern(lhost, allowed_open->listen_host); 3933 free(lhost); 3934 3935 return ret; 3936 } 3937 3938 /* Checks whether a requested remote forwarding is permitted */ 3939 static int 3940 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 3941 { 3942 struct ssh_channels *sc = ssh->chanctxt; 3943 struct permission_set *pset = &sc->remote_perms; 3944 u_int i, permit, permit_adm = 1; 3945 struct permission *perm; 3946 3947 /* XXX apply GatewayPorts override before checking? */ 3948 3949 permit = pset->all_permitted; 3950 if (!permit) { 3951 for (i = 0; i < pset->num_permitted_user; i++) { 3952 perm = &pset->permitted_user[i]; 3953 if (remote_open_match(perm, fwd)) { 3954 permit = 1; 3955 break; 3956 } 3957 } 3958 } 3959 3960 if (pset->num_permitted_admin > 0) { 3961 permit_adm = 0; 3962 for (i = 0; i < pset->num_permitted_admin; i++) { 3963 perm = &pset->permitted_admin[i]; 3964 if (remote_open_match(perm, fwd)) { 3965 permit_adm = 1; 3966 break; 3967 } 3968 } 3969 } 3970 3971 return permit && permit_adm; 3972 } 3973 3974 /* protocol v2 remote port fwd, used by sshd */ 3975 int 3976 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 3977 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 3978 { 3979 if (!check_rfwd_permission(ssh, fwd)) { 3980 ssh_packet_send_debug(ssh, "port forwarding refused"); 3981 if (fwd->listen_path != NULL) 3982 /* XXX always allowed, see remote_open_match() */ 3983 logit("Received request from %.100s port %d to " 3984 "remote forward to path \"%.100s\", " 3985 "but the request was denied.", 3986 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 3987 fwd->listen_path); 3988 else if(fwd->listen_host != NULL) 3989 logit("Received request from %.100s port %d to " 3990 "remote forward to host %.100s port %d, " 3991 "but the request was denied.", 3992 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 3993 fwd->listen_host, fwd->listen_port ); 3994 else 3995 logit("Received request from %.100s port %d to remote " 3996 "forward, but the request was denied.", 3997 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 3998 return 0; 3999 } 4000 if (fwd->listen_path != NULL) { 4001 return channel_setup_fwd_listener_streamlocal(ssh, 4002 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 4003 } else { 4004 return channel_setup_fwd_listener_tcpip(ssh, 4005 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4006 fwd_opts); 4007 } 4008 } 4009 4010 /* 4011 * Translate the requested rfwd listen host to something usable for 4012 * this server. 4013 */ 4014 static const char * 4015 channel_rfwd_bind_host(const char *listen_host) 4016 { 4017 if (listen_host == NULL) { 4018 return "localhost"; 4019 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4020 return ""; 4021 } else 4022 return listen_host; 4023 } 4024 4025 /* 4026 * Initiate forwarding of connections to port "port" on remote host through 4027 * the secure channel to host:port from local side. 4028 * Returns handle (index) for updating the dynamic listen port with 4029 * channel_update_permission(). 4030 */ 4031 int 4032 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4033 { 4034 int r, success = 0, idx = -1; 4035 char *host_to_connect, *listen_host, *listen_path; 4036 int port_to_connect, listen_port; 4037 4038 /* Send the forward request to the remote side. */ 4039 if (fwd->listen_path != NULL) { 4040 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4041 (r = sshpkt_put_cstring(ssh, 4042 "streamlocal-forward@openssh.com")) != 0 || 4043 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4044 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4045 (r = sshpkt_send(ssh)) != 0 || 4046 (r = ssh_packet_write_wait(ssh)) != 0) 4047 fatal_fr(r, "request streamlocal"); 4048 } else { 4049 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4050 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4051 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4052 (r = sshpkt_put_cstring(ssh, 4053 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4054 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4055 (r = sshpkt_send(ssh)) != 0 || 4056 (r = ssh_packet_write_wait(ssh)) != 0) 4057 fatal_fr(r, "request tcpip-forward"); 4058 } 4059 /* Assume that server accepts the request */ 4060 success = 1; 4061 if (success) { 4062 /* Record that connection to this host/port is permitted. */ 4063 host_to_connect = listen_host = listen_path = NULL; 4064 port_to_connect = listen_port = 0; 4065 if (fwd->connect_path != NULL) { 4066 host_to_connect = xstrdup(fwd->connect_path); 4067 port_to_connect = PORT_STREAMLOCAL; 4068 } else { 4069 host_to_connect = xstrdup(fwd->connect_host); 4070 port_to_connect = fwd->connect_port; 4071 } 4072 if (fwd->listen_path != NULL) { 4073 listen_path = xstrdup(fwd->listen_path); 4074 listen_port = PORT_STREAMLOCAL; 4075 } else { 4076 if (fwd->listen_host != NULL) 4077 listen_host = xstrdup(fwd->listen_host); 4078 listen_port = fwd->listen_port; 4079 } 4080 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4081 host_to_connect, port_to_connect, 4082 listen_host, listen_path, listen_port, NULL); 4083 } 4084 return idx; 4085 } 4086 4087 static int 4088 open_match(struct permission *allowed_open, const char *requestedhost, 4089 int requestedport) 4090 { 4091 if (allowed_open->host_to_connect == NULL) 4092 return 0; 4093 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4094 allowed_open->port_to_connect != requestedport) 4095 return 0; 4096 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4097 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4098 return 0; 4099 return 1; 4100 } 4101 4102 /* 4103 * Note that in the listen host/port case 4104 * we don't support FWD_PERMIT_ANY_PORT and 4105 * need to translate between the configured-host (listen_host) 4106 * and what we've sent to the remote server (channel_rfwd_bind_host) 4107 */ 4108 static int 4109 open_listen_match_tcpip(struct permission *allowed_open, 4110 const char *requestedhost, u_short requestedport, int translate) 4111 { 4112 const char *allowed_host; 4113 4114 if (allowed_open->host_to_connect == NULL) 4115 return 0; 4116 if (allowed_open->listen_port != requestedport) 4117 return 0; 4118 if (!translate && allowed_open->listen_host == NULL && 4119 requestedhost == NULL) 4120 return 1; 4121 allowed_host = translate ? 4122 channel_rfwd_bind_host(allowed_open->listen_host) : 4123 allowed_open->listen_host; 4124 if (allowed_host == NULL || requestedhost == NULL || 4125 strcmp(allowed_host, requestedhost) != 0) 4126 return 0; 4127 return 1; 4128 } 4129 4130 static int 4131 open_listen_match_streamlocal(struct permission *allowed_open, 4132 const char *requestedpath) 4133 { 4134 if (allowed_open->host_to_connect == NULL) 4135 return 0; 4136 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4137 return 0; 4138 if (allowed_open->listen_path == NULL || 4139 strcmp(allowed_open->listen_path, requestedpath) != 0) 4140 return 0; 4141 return 1; 4142 } 4143 4144 /* 4145 * Request cancellation of remote forwarding of connection host:port from 4146 * local side. 4147 */ 4148 static int 4149 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4150 const char *host, u_short port) 4151 { 4152 struct ssh_channels *sc = ssh->chanctxt; 4153 struct permission_set *pset = &sc->local_perms; 4154 int r; 4155 u_int i; 4156 struct permission *perm = NULL; 4157 4158 for (i = 0; i < pset->num_permitted_user; i++) { 4159 perm = &pset->permitted_user[i]; 4160 if (open_listen_match_tcpip(perm, host, port, 0)) 4161 break; 4162 perm = NULL; 4163 } 4164 if (perm == NULL) { 4165 debug_f("requested forward not found"); 4166 return -1; 4167 } 4168 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4169 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4170 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4171 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4172 (r = sshpkt_put_u32(ssh, port)) != 0 || 4173 (r = sshpkt_send(ssh)) != 0) 4174 fatal_fr(r, "send cancel"); 4175 4176 fwd_perm_clear(perm); /* unregister */ 4177 4178 return 0; 4179 } 4180 4181 /* 4182 * Request cancellation of remote forwarding of Unix domain socket 4183 * path from local side. 4184 */ 4185 static int 4186 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4187 { 4188 struct ssh_channels *sc = ssh->chanctxt; 4189 struct permission_set *pset = &sc->local_perms; 4190 int r; 4191 u_int i; 4192 struct permission *perm = NULL; 4193 4194 for (i = 0; i < pset->num_permitted_user; i++) { 4195 perm = &pset->permitted_user[i]; 4196 if (open_listen_match_streamlocal(perm, path)) 4197 break; 4198 perm = NULL; 4199 } 4200 if (perm == NULL) { 4201 debug_f("requested forward not found"); 4202 return -1; 4203 } 4204 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4205 (r = sshpkt_put_cstring(ssh, 4206 "cancel-streamlocal-forward@openssh.com")) != 0 || 4207 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4208 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4209 (r = sshpkt_send(ssh)) != 0) 4210 fatal_fr(r, "send cancel"); 4211 4212 fwd_perm_clear(perm); /* unregister */ 4213 4214 return 0; 4215 } 4216 4217 /* 4218 * Request cancellation of remote forwarding of a connection from local side. 4219 */ 4220 int 4221 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4222 { 4223 if (fwd->listen_path != NULL) { 4224 return channel_request_rforward_cancel_streamlocal(ssh, 4225 fwd->listen_path); 4226 } else { 4227 return channel_request_rforward_cancel_tcpip(ssh, 4228 fwd->listen_host, 4229 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4230 } 4231 } 4232 4233 /* 4234 * Permits opening to any host/port if permitted_user[] is empty. This is 4235 * usually called by the server, because the user could connect to any port 4236 * anyway, and the server has no way to know but to trust the client anyway. 4237 */ 4238 void 4239 channel_permit_all(struct ssh *ssh, int where) 4240 { 4241 struct permission_set *pset = permission_set_get(ssh, where); 4242 4243 if (pset->num_permitted_user == 0) 4244 pset->all_permitted = 1; 4245 } 4246 4247 /* 4248 * Permit the specified host/port for forwarding. 4249 */ 4250 void 4251 channel_add_permission(struct ssh *ssh, int who, int where, 4252 char *host, int port) 4253 { 4254 int local = where == FORWARD_LOCAL; 4255 struct permission_set *pset = permission_set_get(ssh, where); 4256 4257 debug("allow %s forwarding to host %s port %d", 4258 fwd_ident(who, where), host, port); 4259 /* 4260 * Remote forwards set listen_host/port, local forwards set 4261 * host/port_to_connect. 4262 */ 4263 permission_set_add(ssh, who, where, 4264 local ? host : 0, local ? port : 0, 4265 local ? NULL : host, NULL, local ? 0 : port, NULL); 4266 pset->all_permitted = 0; 4267 } 4268 4269 /* 4270 * Administratively disable forwarding. 4271 */ 4272 void 4273 channel_disable_admin(struct ssh *ssh, int where) 4274 { 4275 channel_clear_permission(ssh, FORWARD_ADM, where); 4276 permission_set_add(ssh, FORWARD_ADM, where, 4277 NULL, 0, NULL, NULL, 0, NULL); 4278 } 4279 4280 /* 4281 * Clear a list of permitted opens. 4282 */ 4283 void 4284 channel_clear_permission(struct ssh *ssh, int who, int where) 4285 { 4286 struct permission **permp; 4287 u_int *npermp; 4288 4289 permission_set_get_array(ssh, who, where, &permp, &npermp); 4290 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4291 *npermp = 0; 4292 } 4293 4294 /* 4295 * Update the listen port for a dynamic remote forward, after 4296 * the actual 'newport' has been allocated. If 'newport' < 0 is 4297 * passed then they entry will be invalidated. 4298 */ 4299 void 4300 channel_update_permission(struct ssh *ssh, int idx, int newport) 4301 { 4302 struct permission_set *pset = &ssh->chanctxt->local_perms; 4303 4304 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4305 debug_f("index out of range: %d num_permitted_user %d", 4306 idx, pset->num_permitted_user); 4307 return; 4308 } 4309 debug("%s allowed port %d for forwarding to host %s port %d", 4310 newport > 0 ? "Updating" : "Removing", 4311 newport, 4312 pset->permitted_user[idx].host_to_connect, 4313 pset->permitted_user[idx].port_to_connect); 4314 if (newport <= 0) 4315 fwd_perm_clear(&pset->permitted_user[idx]); 4316 else { 4317 pset->permitted_user[idx].listen_port = 4318 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4319 } 4320 } 4321 4322 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4323 int 4324 permitopen_port(const char *p) 4325 { 4326 int port; 4327 4328 if (strcmp(p, "*") == 0) 4329 return FWD_PERMIT_ANY_PORT; 4330 if ((port = a2port(p)) > 0) 4331 return port; 4332 return -1; 4333 } 4334 4335 /* Try to start non-blocking connect to next host in cctx list */ 4336 static int 4337 connect_next(struct channel_connect *cctx) 4338 { 4339 int sock, saved_errno; 4340 struct sockaddr_un *sunaddr; 4341 char ntop[NI_MAXHOST]; 4342 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4343 4344 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4345 switch (cctx->ai->ai_family) { 4346 case AF_UNIX: 4347 /* unix:pathname instead of host:port */ 4348 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4349 strlcpy(ntop, "unix", sizeof(ntop)); 4350 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4351 break; 4352 case AF_INET: 4353 case AF_INET6: 4354 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4355 ntop, sizeof(ntop), strport, sizeof(strport), 4356 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4357 error("connect_next: getnameinfo failed"); 4358 continue; 4359 } 4360 break; 4361 default: 4362 continue; 4363 } 4364 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4365 cctx->ai->ai_protocol)) == -1) { 4366 if (cctx->ai->ai_next == NULL) 4367 error("socket: %.100s", strerror(errno)); 4368 else 4369 verbose("socket: %.100s", strerror(errno)); 4370 continue; 4371 } 4372 if (set_nonblock(sock) == -1) 4373 fatal_f("set_nonblock(%d)", sock); 4374 if (connect(sock, cctx->ai->ai_addr, 4375 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4376 debug("connect_next: host %.100s ([%.100s]:%s): " 4377 "%.100s", cctx->host, ntop, strport, 4378 strerror(errno)); 4379 saved_errno = errno; 4380 close(sock); 4381 errno = saved_errno; 4382 continue; /* fail -- try next */ 4383 } 4384 if (cctx->ai->ai_family != AF_UNIX) 4385 set_nodelay(sock); 4386 debug("connect_next: host %.100s ([%.100s]:%s) " 4387 "in progress, fd=%d", cctx->host, ntop, strport, sock); 4388 cctx->ai = cctx->ai->ai_next; 4389 return sock; 4390 } 4391 return -1; 4392 } 4393 4394 static void 4395 channel_connect_ctx_free(struct channel_connect *cctx) 4396 { 4397 free(cctx->host); 4398 if (cctx->aitop) { 4399 if (cctx->aitop->ai_family == AF_UNIX) 4400 free(cctx->aitop); 4401 else 4402 freeaddrinfo(cctx->aitop); 4403 } 4404 memset(cctx, 0, sizeof(*cctx)); 4405 } 4406 4407 /* 4408 * Return connecting socket to remote host:port or local socket path, 4409 * passing back the failure reason if appropriate. 4410 */ 4411 static int 4412 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4413 char *ctype, char *rname, struct channel_connect *cctx, 4414 int *reason, const char **errmsg) 4415 { 4416 struct addrinfo hints; 4417 int gaierr; 4418 int sock = -1; 4419 char strport[NI_MAXSERV]; 4420 4421 if (port == PORT_STREAMLOCAL) { 4422 struct sockaddr_un *sunaddr; 4423 struct addrinfo *ai; 4424 4425 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4426 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4427 return -1; 4428 } 4429 4430 /* 4431 * Fake up a struct addrinfo for AF_UNIX connections. 4432 * channel_connect_ctx_free() must check ai_family 4433 * and use free() not freeaddirinfo() for AF_UNIX. 4434 */ 4435 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4436 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4437 ai->ai_addr = (struct sockaddr *)(ai + 1); 4438 ai->ai_addrlen = sizeof(*sunaddr); 4439 ai->ai_family = AF_UNIX; 4440 ai->ai_socktype = socktype; 4441 ai->ai_protocol = PF_UNSPEC; 4442 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4443 sunaddr->sun_family = AF_UNIX; 4444 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4445 cctx->aitop = ai; 4446 } else { 4447 memset(&hints, 0, sizeof(hints)); 4448 hints.ai_family = ssh->chanctxt->IPv4or6; 4449 hints.ai_socktype = socktype; 4450 snprintf(strport, sizeof strport, "%d", port); 4451 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4452 != 0) { 4453 if (errmsg != NULL) 4454 *errmsg = ssh_gai_strerror(gaierr); 4455 if (reason != NULL) 4456 *reason = SSH2_OPEN_CONNECT_FAILED; 4457 error("connect_to %.100s: unknown host (%s)", name, 4458 ssh_gai_strerror(gaierr)); 4459 return -1; 4460 } 4461 } 4462 4463 cctx->host = xstrdup(name); 4464 cctx->port = port; 4465 cctx->ai = cctx->aitop; 4466 4467 if ((sock = connect_next(cctx)) == -1) { 4468 error("connect to %.100s port %d failed: %s", 4469 name, port, strerror(errno)); 4470 return -1; 4471 } 4472 4473 return sock; 4474 } 4475 4476 /* Return CONNECTING channel to remote host:port or local socket path */ 4477 static Channel * 4478 connect_to(struct ssh *ssh, const char *host, int port, 4479 char *ctype, char *rname) 4480 { 4481 struct channel_connect cctx; 4482 Channel *c; 4483 int sock; 4484 4485 memset(&cctx, 0, sizeof(cctx)); 4486 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4487 &cctx, NULL, NULL); 4488 if (sock == -1) { 4489 channel_connect_ctx_free(&cctx); 4490 return NULL; 4491 } 4492 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4493 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4494 c->host_port = port; 4495 c->path = xstrdup(host); 4496 c->connect_ctx = cctx; 4497 4498 return c; 4499 } 4500 4501 /* 4502 * returns either the newly connected channel or the downstream channel 4503 * that needs to deal with this connection. 4504 */ 4505 Channel * 4506 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4507 u_short listen_port, char *ctype, char *rname) 4508 { 4509 struct ssh_channels *sc = ssh->chanctxt; 4510 struct permission_set *pset = &sc->local_perms; 4511 u_int i; 4512 struct permission *perm; 4513 4514 for (i = 0; i < pset->num_permitted_user; i++) { 4515 perm = &pset->permitted_user[i]; 4516 if (open_listen_match_tcpip(perm, 4517 listen_host, listen_port, 1)) { 4518 if (perm->downstream) 4519 return perm->downstream; 4520 if (perm->port_to_connect == 0) 4521 return rdynamic_connect_prepare(ssh, 4522 ctype, rname); 4523 return connect_to(ssh, 4524 perm->host_to_connect, perm->port_to_connect, 4525 ctype, rname); 4526 } 4527 } 4528 error("WARNING: Server requests forwarding for unknown listen_port %d", 4529 listen_port); 4530 return NULL; 4531 } 4532 4533 Channel * 4534 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4535 char *ctype, char *rname) 4536 { 4537 struct ssh_channels *sc = ssh->chanctxt; 4538 struct permission_set *pset = &sc->local_perms; 4539 u_int i; 4540 struct permission *perm; 4541 4542 for (i = 0; i < pset->num_permitted_user; i++) { 4543 perm = &pset->permitted_user[i]; 4544 if (open_listen_match_streamlocal(perm, path)) { 4545 return connect_to(ssh, 4546 perm->host_to_connect, perm->port_to_connect, 4547 ctype, rname); 4548 } 4549 } 4550 error("WARNING: Server requests forwarding for unknown path %.100s", 4551 path); 4552 return NULL; 4553 } 4554 4555 /* Check if connecting to that port is permitted and connect. */ 4556 Channel * 4557 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4558 char *ctype, char *rname, int *reason, const char **errmsg) 4559 { 4560 struct ssh_channels *sc = ssh->chanctxt; 4561 struct permission_set *pset = &sc->local_perms; 4562 struct channel_connect cctx; 4563 Channel *c; 4564 u_int i, permit, permit_adm = 1; 4565 int sock; 4566 struct permission *perm; 4567 4568 permit = pset->all_permitted; 4569 if (!permit) { 4570 for (i = 0; i < pset->num_permitted_user; i++) { 4571 perm = &pset->permitted_user[i]; 4572 if (open_match(perm, host, port)) { 4573 permit = 1; 4574 break; 4575 } 4576 } 4577 } 4578 4579 if (pset->num_permitted_admin > 0) { 4580 permit_adm = 0; 4581 for (i = 0; i < pset->num_permitted_admin; i++) { 4582 perm = &pset->permitted_admin[i]; 4583 if (open_match(perm, host, port)) { 4584 permit_adm = 1; 4585 break; 4586 } 4587 } 4588 } 4589 4590 if (!permit || !permit_adm) { 4591 logit("Received request from %.100s port %d to connect to " 4592 "host %.100s port %d, but the request was denied.", 4593 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4594 if (reason != NULL) 4595 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4596 return NULL; 4597 } 4598 4599 memset(&cctx, 0, sizeof(cctx)); 4600 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4601 &cctx, reason, errmsg); 4602 if (sock == -1) { 4603 channel_connect_ctx_free(&cctx); 4604 return NULL; 4605 } 4606 4607 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4608 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4609 c->host_port = port; 4610 c->path = xstrdup(host); 4611 c->connect_ctx = cctx; 4612 4613 return c; 4614 } 4615 4616 /* Check if connecting to that path is permitted and connect. */ 4617 Channel * 4618 channel_connect_to_path(struct ssh *ssh, const char *path, 4619 char *ctype, char *rname) 4620 { 4621 struct ssh_channels *sc = ssh->chanctxt; 4622 struct permission_set *pset = &sc->local_perms; 4623 u_int i, permit, permit_adm = 1; 4624 struct permission *perm; 4625 4626 permit = pset->all_permitted; 4627 if (!permit) { 4628 for (i = 0; i < pset->num_permitted_user; i++) { 4629 perm = &pset->permitted_user[i]; 4630 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4631 permit = 1; 4632 break; 4633 } 4634 } 4635 } 4636 4637 if (pset->num_permitted_admin > 0) { 4638 permit_adm = 0; 4639 for (i = 0; i < pset->num_permitted_admin; i++) { 4640 perm = &pset->permitted_admin[i]; 4641 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4642 permit_adm = 1; 4643 break; 4644 } 4645 } 4646 } 4647 4648 if (!permit || !permit_adm) { 4649 logit("Received request to connect to path %.100s, " 4650 "but the request was denied.", path); 4651 return NULL; 4652 } 4653 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4654 } 4655 4656 void 4657 channel_send_window_changes(struct ssh *ssh) 4658 { 4659 struct ssh_channels *sc = ssh->chanctxt; 4660 struct winsize ws; 4661 int r; 4662 u_int i; 4663 4664 for (i = 0; i < sc->channels_alloc; i++) { 4665 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4666 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4667 continue; 4668 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4669 continue; 4670 channel_request_start(ssh, i, "window-change", 0); 4671 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4672 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4673 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4674 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4675 (r = sshpkt_send(ssh)) != 0) 4676 fatal_fr(r, "channel %u; send window-change", i); 4677 } 4678 } 4679 4680 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4681 static Channel * 4682 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4683 { 4684 Channel *c; 4685 int r; 4686 4687 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4688 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4689 c->host_port = 0; 4690 c->path = NULL; 4691 4692 /* 4693 * We need to open the channel before we have a FD, 4694 * so that we can get SOCKS header from peer. 4695 */ 4696 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4697 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4698 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4699 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4700 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4701 fatal_fr(r, "channel %i; confirm", c->self); 4702 return c; 4703 } 4704 4705 /* Return CONNECTING socket to remote host:port or local socket path */ 4706 static int 4707 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4708 { 4709 struct ssh_channels *sc = ssh->chanctxt; 4710 struct permission_set *pset = &sc->local_perms; 4711 struct permission *perm; 4712 struct channel_connect cctx; 4713 u_int i, permit_adm = 1; 4714 int sock; 4715 4716 if (pset->num_permitted_admin > 0) { 4717 permit_adm = 0; 4718 for (i = 0; i < pset->num_permitted_admin; i++) { 4719 perm = &pset->permitted_admin[i]; 4720 if (open_match(perm, c->path, c->host_port)) { 4721 permit_adm = 1; 4722 break; 4723 } 4724 } 4725 } 4726 if (!permit_adm) { 4727 debug_f("requested forward not permitted"); 4728 return -1; 4729 } 4730 4731 memset(&cctx, 0, sizeof(cctx)); 4732 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4733 NULL, &cctx, NULL, NULL); 4734 if (sock == -1) 4735 channel_connect_ctx_free(&cctx); 4736 else { 4737 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4738 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4739 c->connect_ctx = cctx; 4740 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4741 } 4742 return sock; 4743 } 4744 4745 /* -- X11 forwarding */ 4746 4747 /* 4748 * Creates an internet domain socket for listening for X11 connections. 4749 * Returns 0 and a suitable display number for the DISPLAY variable 4750 * stored in display_numberp , or -1 if an error occurs. 4751 */ 4752 int 4753 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4754 int x11_use_localhost, int single_connection, 4755 u_int *display_numberp, int **chanids) 4756 { 4757 Channel *nc = NULL; 4758 int display_number, sock; 4759 u_short port; 4760 struct addrinfo hints, *ai, *aitop; 4761 char strport[NI_MAXSERV]; 4762 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4763 4764 if (chanids == NULL) 4765 return -1; 4766 4767 for (display_number = x11_display_offset; 4768 display_number < MAX_DISPLAYS; 4769 display_number++) { 4770 port = 6000 + display_number; 4771 memset(&hints, 0, sizeof(hints)); 4772 hints.ai_family = ssh->chanctxt->IPv4or6; 4773 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4774 hints.ai_socktype = SOCK_STREAM; 4775 snprintf(strport, sizeof strport, "%d", port); 4776 if ((gaierr = getaddrinfo(NULL, strport, 4777 &hints, &aitop)) != 0) { 4778 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4779 return -1; 4780 } 4781 for (ai = aitop; ai; ai = ai->ai_next) { 4782 if (ai->ai_family != AF_INET && 4783 ai->ai_family != AF_INET6) 4784 continue; 4785 sock = socket(ai->ai_family, ai->ai_socktype, 4786 ai->ai_protocol); 4787 if (sock == -1) { 4788 error("socket: %.100s", strerror(errno)); 4789 freeaddrinfo(aitop); 4790 return -1; 4791 } 4792 set_reuseaddr(sock); 4793 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4794 debug2_f("bind port %d: %.100s", port, 4795 strerror(errno)); 4796 close(sock); 4797 for (n = 0; n < num_socks; n++) 4798 close(socks[n]); 4799 num_socks = 0; 4800 break; 4801 } 4802 socks[num_socks++] = sock; 4803 if (num_socks == NUM_SOCKS) 4804 break; 4805 } 4806 freeaddrinfo(aitop); 4807 if (num_socks > 0) 4808 break; 4809 } 4810 if (display_number >= MAX_DISPLAYS) { 4811 error("Failed to allocate internet-domain X11 display socket."); 4812 return -1; 4813 } 4814 /* Start listening for connections on the socket. */ 4815 for (n = 0; n < num_socks; n++) { 4816 sock = socks[n]; 4817 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 4818 error("listen: %.100s", strerror(errno)); 4819 close(sock); 4820 return -1; 4821 } 4822 } 4823 4824 /* Allocate a channel for each socket. */ 4825 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 4826 for (n = 0; n < num_socks; n++) { 4827 sock = socks[n]; 4828 nc = channel_new(ssh, "x11 listener", 4829 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4830 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 4831 0, "X11 inet listener", 1); 4832 nc->single_connection = single_connection; 4833 (*chanids)[n] = nc->self; 4834 } 4835 (*chanids)[n] = -1; 4836 4837 /* Return the display number for the DISPLAY environment variable. */ 4838 *display_numberp = display_number; 4839 return 0; 4840 } 4841 4842 static int 4843 connect_local_xsocket(u_int dnr) 4844 { 4845 int sock; 4846 struct sockaddr_un addr; 4847 4848 sock = socket(AF_UNIX, SOCK_STREAM, 0); 4849 if (sock == -1) 4850 error("socket: %.100s", strerror(errno)); 4851 memset(&addr, 0, sizeof(addr)); 4852 addr.sun_family = AF_UNIX; 4853 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 4854 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 4855 return sock; 4856 close(sock); 4857 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 4858 return -1; 4859 } 4860 4861 int 4862 x11_connect_display(struct ssh *ssh) 4863 { 4864 u_int display_number; 4865 const char *display; 4866 char buf[1024], *cp; 4867 struct addrinfo hints, *ai, *aitop; 4868 char strport[NI_MAXSERV]; 4869 int gaierr, sock = 0; 4870 4871 /* Try to open a socket for the local X server. */ 4872 display = getenv("DISPLAY"); 4873 if (!display) { 4874 error("DISPLAY not set."); 4875 return -1; 4876 } 4877 /* 4878 * Now we decode the value of the DISPLAY variable and make a 4879 * connection to the real X server. 4880 */ 4881 4882 /* 4883 * Check if it is a unix domain socket. Unix domain displays are in 4884 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 4885 */ 4886 if (strncmp(display, "unix:", 5) == 0 || 4887 display[0] == ':') { 4888 /* Connect to the unix domain socket. */ 4889 if (sscanf(strrchr(display, ':') + 1, "%u", 4890 &display_number) != 1) { 4891 error("Could not parse display number from DISPLAY: " 4892 "%.100s", display); 4893 return -1; 4894 } 4895 /* Create a socket. */ 4896 sock = connect_local_xsocket(display_number); 4897 if (sock < 0) 4898 return -1; 4899 4900 /* OK, we now have a connection to the display. */ 4901 return sock; 4902 } 4903 /* 4904 * Connect to an inet socket. The DISPLAY value is supposedly 4905 * hostname:d[.s], where hostname may also be numeric IP address. 4906 */ 4907 strlcpy(buf, display, sizeof(buf)); 4908 cp = strchr(buf, ':'); 4909 if (!cp) { 4910 error("Could not find ':' in DISPLAY: %.100s", display); 4911 return -1; 4912 } 4913 *cp = 0; 4914 /* 4915 * buf now contains the host name. But first we parse the 4916 * display number. 4917 */ 4918 if (sscanf(cp + 1, "%u", &display_number) != 1) { 4919 error("Could not parse display number from DISPLAY: %.100s", 4920 display); 4921 return -1; 4922 } 4923 4924 /* Look up the host address */ 4925 memset(&hints, 0, sizeof(hints)); 4926 hints.ai_family = ssh->chanctxt->IPv4or6; 4927 hints.ai_socktype = SOCK_STREAM; 4928 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 4929 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 4930 error("%.100s: unknown host. (%s)", buf, 4931 ssh_gai_strerror(gaierr)); 4932 return -1; 4933 } 4934 for (ai = aitop; ai; ai = ai->ai_next) { 4935 /* Create a socket. */ 4936 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 4937 if (sock == -1) { 4938 debug2("socket: %.100s", strerror(errno)); 4939 continue; 4940 } 4941 /* Connect it to the display. */ 4942 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4943 debug2("connect %.100s port %u: %.100s", buf, 4944 6000 + display_number, strerror(errno)); 4945 close(sock); 4946 continue; 4947 } 4948 /* Success */ 4949 break; 4950 } 4951 freeaddrinfo(aitop); 4952 if (!ai) { 4953 error("connect %.100s port %u: %.100s", buf, 4954 6000 + display_number, strerror(errno)); 4955 return -1; 4956 } 4957 set_nodelay(sock); 4958 return sock; 4959 } 4960 4961 /* 4962 * Requests forwarding of X11 connections, generates fake authentication 4963 * data, and enables authentication spoofing. 4964 * This should be called in the client only. 4965 */ 4966 void 4967 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 4968 const char *disp, const char *proto, const char *data, int want_reply) 4969 { 4970 struct ssh_channels *sc = ssh->chanctxt; 4971 u_int data_len = (u_int) strlen(data) / 2; 4972 u_int i, value; 4973 const char *cp; 4974 char *new_data; 4975 int r, screen_number; 4976 4977 if (sc->x11_saved_display == NULL) 4978 sc->x11_saved_display = xstrdup(disp); 4979 else if (strcmp(disp, sc->x11_saved_display) != 0) { 4980 error("x11_request_forwarding_with_spoofing: different " 4981 "$DISPLAY already forwarded"); 4982 return; 4983 } 4984 4985 cp = strchr(disp, ':'); 4986 if (cp) 4987 cp = strchr(cp, '.'); 4988 if (cp) 4989 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 4990 else 4991 screen_number = 0; 4992 4993 if (sc->x11_saved_proto == NULL) { 4994 /* Save protocol name. */ 4995 sc->x11_saved_proto = xstrdup(proto); 4996 4997 /* Extract real authentication data. */ 4998 sc->x11_saved_data = xmalloc(data_len); 4999 for (i = 0; i < data_len; i++) { 5000 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 5001 fatal("x11_request_forwarding: bad " 5002 "authentication data: %.100s", data); 5003 } 5004 sc->x11_saved_data[i] = value; 5005 } 5006 sc->x11_saved_data_len = data_len; 5007 5008 /* Generate fake data of the same length. */ 5009 sc->x11_fake_data = xmalloc(data_len); 5010 arc4random_buf(sc->x11_fake_data, data_len); 5011 sc->x11_fake_data_len = data_len; 5012 } 5013 5014 /* Convert the fake data into hex. */ 5015 new_data = tohex(sc->x11_fake_data, data_len); 5016 5017 /* Send the request packet. */ 5018 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5019 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5020 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5021 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5022 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5023 (r = sshpkt_send(ssh)) != 0 || 5024 (r = ssh_packet_write_wait(ssh)) != 0) 5025 fatal_fr(r, "send x11-req"); 5026 free(new_data); 5027 } 5028