1 /* $OpenBSD: channels.c,v 1.417 2022/04/20 04:19:11 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 if (rfd != -1) 300 fcntl(rfd, F_SETFD, FD_CLOEXEC); 301 if (wfd != -1 && wfd != rfd) 302 fcntl(wfd, F_SETFD, FD_CLOEXEC); 303 if (efd != -1 && efd != rfd && efd != wfd) 304 fcntl(efd, F_SETFD, FD_CLOEXEC); 305 306 c->rfd = rfd; 307 c->wfd = wfd; 308 c->sock = (rfd == wfd) ? rfd : -1; 309 c->efd = efd; 310 c->extended_usage = extusage; 311 312 if ((c->isatty = is_tty) != 0) 313 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 314 315 /* enable nonblocking mode */ 316 c->restore_block = 0; 317 if (nonblock == CHANNEL_NONBLOCK_STDIO) { 318 /* 319 * Special handling for stdio file descriptors: do not set 320 * non-blocking mode if they are TTYs. Otherwise prepare to 321 * restore their blocking state on exit to avoid interfering 322 * with other programs that follow. 323 */ 324 if (rfd != -1 && !isatty(rfd) && fcntl(rfd, F_GETFL) == 0) { 325 c->restore_block |= CHANNEL_RESTORE_RFD; 326 set_nonblock(rfd); 327 } 328 if (wfd != -1 && !isatty(wfd) && fcntl(wfd, F_GETFL) == 0) { 329 c->restore_block |= CHANNEL_RESTORE_WFD; 330 set_nonblock(wfd); 331 } 332 if (efd != -1 && !isatty(efd) && fcntl(efd, F_GETFL) == 0) { 333 c->restore_block |= CHANNEL_RESTORE_EFD; 334 set_nonblock(efd); 335 } 336 } else if (nonblock) { 337 if (rfd != -1) 338 set_nonblock(rfd); 339 if (wfd != -1) 340 set_nonblock(wfd); 341 if (efd != -1) 342 set_nonblock(efd); 343 } 344 } 345 346 /* 347 * Allocate a new channel object and set its type and socket. This will cause 348 * remote_name to be freed. 349 */ 350 Channel * 351 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 352 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) 353 { 354 struct ssh_channels *sc = ssh->chanctxt; 355 u_int i, found; 356 Channel *c; 357 int r; 358 359 /* Try to find a free slot where to put the new channel. */ 360 for (i = 0; i < sc->channels_alloc; i++) { 361 if (sc->channels[i] == NULL) { 362 /* Found a free slot. */ 363 found = i; 364 break; 365 } 366 } 367 if (i >= sc->channels_alloc) { 368 /* 369 * There are no free slots. Take last+1 slot and expand 370 * the array. 371 */ 372 found = sc->channels_alloc; 373 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 374 fatal_f("internal error: channels_alloc %d too big", 375 sc->channels_alloc); 376 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 377 sc->channels_alloc + 10, sizeof(*sc->channels)); 378 sc->channels_alloc += 10; 379 debug2("channel: expanding %d", sc->channels_alloc); 380 } 381 /* Initialize and return new channel. */ 382 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 383 if ((c->input = sshbuf_new()) == NULL || 384 (c->output = sshbuf_new()) == NULL || 385 (c->extended = sshbuf_new()) == NULL) 386 fatal_f("sshbuf_new failed"); 387 if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0) 388 fatal_fr(r, "sshbuf_set_max_size"); 389 c->ostate = CHAN_OUTPUT_OPEN; 390 c->istate = CHAN_INPUT_OPEN; 391 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 392 c->self = found; 393 c->type = type; 394 c->ctype = ctype; 395 c->local_window = window; 396 c->local_window_max = window; 397 c->local_maxpacket = maxpack; 398 c->remote_name = xstrdup(remote_name); 399 c->ctl_chan = -1; 400 c->delayed = 1; /* prevent call to channel_post handler */ 401 TAILQ_INIT(&c->status_confirms); 402 debug("channel %d: new [%s]", found, remote_name); 403 return c; 404 } 405 406 int 407 channel_close_fd(struct ssh *ssh, Channel *c, int *fdp) 408 { 409 int ret, fd = *fdp; 410 411 if (fd == -1) 412 return 0; 413 414 if ((*fdp == c->rfd && (c->restore_block & CHANNEL_RESTORE_RFD) != 0) || 415 (*fdp == c->wfd && (c->restore_block & CHANNEL_RESTORE_WFD) != 0) || 416 (*fdp == c->efd && (c->restore_block & CHANNEL_RESTORE_EFD) != 0)) 417 (void)fcntl(*fdp, F_SETFL, 0); /* restore blocking */ 418 419 if (*fdp == c->rfd) { 420 c->io_want &= ~SSH_CHAN_IO_RFD; 421 c->io_ready &= ~SSH_CHAN_IO_RFD; 422 c->rfd = -1; 423 c->pfds[0] = -1; 424 } 425 if (*fdp == c->wfd) { 426 c->io_want &= ~SSH_CHAN_IO_WFD; 427 c->io_ready &= ~SSH_CHAN_IO_WFD; 428 c->wfd = -1; 429 c->pfds[1] = -1; 430 } 431 if (*fdp == c->efd) { 432 c->io_want &= ~SSH_CHAN_IO_EFD; 433 c->io_ready &= ~SSH_CHAN_IO_EFD; 434 c->efd = -1; 435 c->pfds[2] = -1; 436 } 437 if (*fdp == c->sock) { 438 c->io_want &= ~SSH_CHAN_IO_SOCK; 439 c->io_ready &= ~SSH_CHAN_IO_SOCK; 440 c->sock = -1; 441 c->pfds[3] = -1; 442 } 443 444 ret = close(fd); 445 *fdp = -1; /* probably redundant */ 446 return ret; 447 } 448 449 /* Close all channel fd/socket. */ 450 static void 451 channel_close_fds(struct ssh *ssh, Channel *c) 452 { 453 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 454 455 channel_close_fd(ssh, c, &c->sock); 456 if (rfd != sock) 457 channel_close_fd(ssh, c, &c->rfd); 458 if (wfd != sock && wfd != rfd) 459 channel_close_fd(ssh, c, &c->wfd); 460 if (efd != sock && efd != rfd && efd != wfd) 461 channel_close_fd(ssh, c, &c->efd); 462 } 463 464 static void 465 fwd_perm_clear(struct permission *perm) 466 { 467 free(perm->host_to_connect); 468 free(perm->listen_host); 469 free(perm->listen_path); 470 memset(perm, 0, sizeof(*perm)); 471 } 472 473 /* Returns an printable name for the specified forwarding permission list */ 474 static const char * 475 fwd_ident(int who, int where) 476 { 477 if (who == FORWARD_ADM) { 478 if (where == FORWARD_LOCAL) 479 return "admin local"; 480 else if (where == FORWARD_REMOTE) 481 return "admin remote"; 482 } else if (who == FORWARD_USER) { 483 if (where == FORWARD_LOCAL) 484 return "user local"; 485 else if (where == FORWARD_REMOTE) 486 return "user remote"; 487 } 488 fatal("Unknown forward permission list %d/%d", who, where); 489 } 490 491 /* Returns the forwarding permission list for the specified direction */ 492 static struct permission_set * 493 permission_set_get(struct ssh *ssh, int where) 494 { 495 struct ssh_channels *sc = ssh->chanctxt; 496 497 switch (where) { 498 case FORWARD_LOCAL: 499 return &sc->local_perms; 500 break; 501 case FORWARD_REMOTE: 502 return &sc->remote_perms; 503 break; 504 default: 505 fatal_f("invalid forwarding direction %d", where); 506 } 507 } 508 509 /* Returns pointers to the specified forwarding list and its element count */ 510 static void 511 permission_set_get_array(struct ssh *ssh, int who, int where, 512 struct permission ***permpp, u_int **npermpp) 513 { 514 struct permission_set *pset = permission_set_get(ssh, where); 515 516 switch (who) { 517 case FORWARD_USER: 518 *permpp = &pset->permitted_user; 519 *npermpp = &pset->num_permitted_user; 520 break; 521 case FORWARD_ADM: 522 *permpp = &pset->permitted_admin; 523 *npermpp = &pset->num_permitted_admin; 524 break; 525 default: 526 fatal_f("invalid forwarding client %d", who); 527 } 528 } 529 530 /* Adds an entry to the specified forwarding list */ 531 static int 532 permission_set_add(struct ssh *ssh, int who, int where, 533 const char *host_to_connect, int port_to_connect, 534 const char *listen_host, const char *listen_path, int listen_port, 535 Channel *downstream) 536 { 537 struct permission **permp; 538 u_int n, *npermp; 539 540 permission_set_get_array(ssh, who, where, &permp, &npermp); 541 542 if (*npermp >= INT_MAX) 543 fatal_f("%s overflow", fwd_ident(who, where)); 544 545 *permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp)); 546 n = (*npermp)++; 547 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 548 (*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect); 549 (*permp)[n].port_to_connect = port_to_connect; 550 (*permp)[n].listen_host = MAYBE_DUP(listen_host); 551 (*permp)[n].listen_path = MAYBE_DUP(listen_path); 552 (*permp)[n].listen_port = listen_port; 553 (*permp)[n].downstream = downstream; 554 #undef MAYBE_DUP 555 return (int)n; 556 } 557 558 static void 559 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 560 { 561 struct ssh_channels *sc = ssh->chanctxt; 562 struct permission_set *pset = &sc->local_perms; 563 struct permission *perm; 564 int r; 565 u_int i; 566 567 for (i = 0; i < pset->num_permitted_user; i++) { 568 perm = &pset->permitted_user[i]; 569 if (perm->downstream != c) 570 continue; 571 572 /* cancel on the server, since mux client is gone */ 573 debug("channel %d: cleanup remote forward for %s:%u", 574 c->self, perm->listen_host, perm->listen_port); 575 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 576 (r = sshpkt_put_cstring(ssh, 577 "cancel-tcpip-forward")) != 0 || 578 (r = sshpkt_put_u8(ssh, 0)) != 0 || 579 (r = sshpkt_put_cstring(ssh, 580 channel_rfwd_bind_host(perm->listen_host))) != 0 || 581 (r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 || 582 (r = sshpkt_send(ssh)) != 0) { 583 fatal_fr(r, "channel %i", c->self); 584 } 585 fwd_perm_clear(perm); /* unregister */ 586 } 587 } 588 589 /* Free the channel and close its fd/socket. */ 590 void 591 channel_free(struct ssh *ssh, Channel *c) 592 { 593 struct ssh_channels *sc = ssh->chanctxt; 594 char *s; 595 u_int i, n; 596 Channel *other; 597 struct channel_confirm *cc; 598 599 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 600 if ((other = sc->channels[i]) == NULL) 601 continue; 602 n++; 603 /* detach from mux client and prepare for closing */ 604 if (c->type == SSH_CHANNEL_MUX_CLIENT && 605 other->type == SSH_CHANNEL_MUX_PROXY && 606 other->mux_ctx == c) { 607 other->mux_ctx = NULL; 608 other->type = SSH_CHANNEL_OPEN; 609 other->istate = CHAN_INPUT_CLOSED; 610 other->ostate = CHAN_OUTPUT_CLOSED; 611 } 612 } 613 debug("channel %d: free: %s, nchannels %u", c->self, 614 c->remote_name ? c->remote_name : "???", n); 615 616 if (c->type == SSH_CHANNEL_MUX_CLIENT) { 617 mux_remove_remote_forwardings(ssh, c); 618 free(c->mux_ctx); 619 c->mux_ctx = NULL; 620 } else if (c->type == SSH_CHANNEL_MUX_LISTENER) { 621 free(c->mux_ctx); 622 c->mux_ctx = NULL; 623 } 624 625 if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) { 626 s = channel_open_message(ssh); 627 debug3("channel %d: status: %s", c->self, s); 628 free(s); 629 } 630 631 channel_close_fds(ssh, c); 632 sshbuf_free(c->input); 633 sshbuf_free(c->output); 634 sshbuf_free(c->extended); 635 c->input = c->output = c->extended = NULL; 636 free(c->remote_name); 637 c->remote_name = NULL; 638 free(c->path); 639 c->path = NULL; 640 free(c->listening_addr); 641 c->listening_addr = NULL; 642 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 643 if (cc->abandon_cb != NULL) 644 cc->abandon_cb(ssh, c, cc->ctx); 645 TAILQ_REMOVE(&c->status_confirms, cc, entry); 646 freezero(cc, sizeof(*cc)); 647 } 648 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 649 c->filter_cleanup(ssh, c->self, c->filter_ctx); 650 sc->channels[c->self] = NULL; 651 freezero(c, sizeof(*c)); 652 } 653 654 void 655 channel_free_all(struct ssh *ssh) 656 { 657 u_int i; 658 struct ssh_channels *sc = ssh->chanctxt; 659 660 for (i = 0; i < sc->channels_alloc; i++) 661 if (sc->channels[i] != NULL) 662 channel_free(ssh, sc->channels[i]); 663 664 free(sc->channels); 665 sc->channels = NULL; 666 sc->channels_alloc = 0; 667 668 free(sc->x11_saved_display); 669 sc->x11_saved_display = NULL; 670 671 free(sc->x11_saved_proto); 672 sc->x11_saved_proto = NULL; 673 674 free(sc->x11_saved_data); 675 sc->x11_saved_data = NULL; 676 sc->x11_saved_data_len = 0; 677 678 free(sc->x11_fake_data); 679 sc->x11_fake_data = NULL; 680 sc->x11_fake_data_len = 0; 681 } 682 683 /* 684 * Closes the sockets/fds of all channels. This is used to close extra file 685 * descriptors after a fork. 686 */ 687 void 688 channel_close_all(struct ssh *ssh) 689 { 690 u_int i; 691 692 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 693 if (ssh->chanctxt->channels[i] != NULL) 694 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 695 } 696 697 /* 698 * Stop listening to channels. 699 */ 700 void 701 channel_stop_listening(struct ssh *ssh) 702 { 703 u_int i; 704 Channel *c; 705 706 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 707 c = ssh->chanctxt->channels[i]; 708 if (c != NULL) { 709 switch (c->type) { 710 case SSH_CHANNEL_AUTH_SOCKET: 711 case SSH_CHANNEL_PORT_LISTENER: 712 case SSH_CHANNEL_RPORT_LISTENER: 713 case SSH_CHANNEL_X11_LISTENER: 714 case SSH_CHANNEL_UNIX_LISTENER: 715 case SSH_CHANNEL_RUNIX_LISTENER: 716 channel_close_fd(ssh, c, &c->sock); 717 channel_free(ssh, c); 718 break; 719 } 720 } 721 } 722 } 723 724 /* 725 * Returns true if no channel has too much buffered data, and false if one or 726 * more channel is overfull. 727 */ 728 int 729 channel_not_very_much_buffered_data(struct ssh *ssh) 730 { 731 u_int i; 732 u_int maxsize = ssh_packet_get_maxsize(ssh); 733 Channel *c; 734 735 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 736 c = ssh->chanctxt->channels[i]; 737 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 738 continue; 739 if (sshbuf_len(c->output) > maxsize) { 740 debug2("channel %d: big output buffer %zu > %u", 741 c->self, sshbuf_len(c->output), maxsize); 742 return 0; 743 } 744 } 745 return 1; 746 } 747 748 /* Returns true if any channel is still open. */ 749 int 750 channel_still_open(struct ssh *ssh) 751 { 752 u_int i; 753 Channel *c; 754 755 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 756 c = ssh->chanctxt->channels[i]; 757 if (c == NULL) 758 continue; 759 switch (c->type) { 760 case SSH_CHANNEL_X11_LISTENER: 761 case SSH_CHANNEL_PORT_LISTENER: 762 case SSH_CHANNEL_RPORT_LISTENER: 763 case SSH_CHANNEL_MUX_LISTENER: 764 case SSH_CHANNEL_CLOSED: 765 case SSH_CHANNEL_AUTH_SOCKET: 766 case SSH_CHANNEL_DYNAMIC: 767 case SSH_CHANNEL_RDYNAMIC_OPEN: 768 case SSH_CHANNEL_CONNECTING: 769 case SSH_CHANNEL_ZOMBIE: 770 case SSH_CHANNEL_ABANDONED: 771 case SSH_CHANNEL_UNIX_LISTENER: 772 case SSH_CHANNEL_RUNIX_LISTENER: 773 continue; 774 case SSH_CHANNEL_LARVAL: 775 continue; 776 case SSH_CHANNEL_OPENING: 777 case SSH_CHANNEL_OPEN: 778 case SSH_CHANNEL_RDYNAMIC_FINISH: 779 case SSH_CHANNEL_X11_OPEN: 780 case SSH_CHANNEL_MUX_CLIENT: 781 case SSH_CHANNEL_MUX_PROXY: 782 return 1; 783 default: 784 fatal_f("bad channel type %d", c->type); 785 /* NOTREACHED */ 786 } 787 } 788 return 0; 789 } 790 791 /* Returns the id of an open channel suitable for keepaliving */ 792 int 793 channel_find_open(struct ssh *ssh) 794 { 795 u_int i; 796 Channel *c; 797 798 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 799 c = ssh->chanctxt->channels[i]; 800 if (c == NULL || !c->have_remote_id) 801 continue; 802 switch (c->type) { 803 case SSH_CHANNEL_CLOSED: 804 case SSH_CHANNEL_DYNAMIC: 805 case SSH_CHANNEL_RDYNAMIC_OPEN: 806 case SSH_CHANNEL_RDYNAMIC_FINISH: 807 case SSH_CHANNEL_X11_LISTENER: 808 case SSH_CHANNEL_PORT_LISTENER: 809 case SSH_CHANNEL_RPORT_LISTENER: 810 case SSH_CHANNEL_MUX_LISTENER: 811 case SSH_CHANNEL_MUX_CLIENT: 812 case SSH_CHANNEL_MUX_PROXY: 813 case SSH_CHANNEL_OPENING: 814 case SSH_CHANNEL_CONNECTING: 815 case SSH_CHANNEL_ZOMBIE: 816 case SSH_CHANNEL_ABANDONED: 817 case SSH_CHANNEL_UNIX_LISTENER: 818 case SSH_CHANNEL_RUNIX_LISTENER: 819 continue; 820 case SSH_CHANNEL_LARVAL: 821 case SSH_CHANNEL_AUTH_SOCKET: 822 case SSH_CHANNEL_OPEN: 823 case SSH_CHANNEL_X11_OPEN: 824 return i; 825 default: 826 fatal_f("bad channel type %d", c->type); 827 /* NOTREACHED */ 828 } 829 } 830 return -1; 831 } 832 833 /* Returns the state of the channel's extended usage flag */ 834 const char * 835 channel_format_extended_usage(const Channel *c) 836 { 837 if (c->efd == -1) 838 return "closed"; 839 840 switch (c->extended_usage) { 841 case CHAN_EXTENDED_WRITE: 842 return "write"; 843 case CHAN_EXTENDED_READ: 844 return "read"; 845 case CHAN_EXTENDED_IGNORE: 846 return "ignore"; 847 default: 848 return "UNKNOWN"; 849 } 850 } 851 852 static char * 853 channel_format_status(const Channel *c) 854 { 855 char *ret = NULL; 856 857 xasprintf(&ret, "t%d %s%u i%u/%zu o%u/%zu e[%s]/%zu " 858 "fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x", 859 c->type, 860 c->have_remote_id ? "r" : "nr", c->remote_id, 861 c->istate, sshbuf_len(c->input), 862 c->ostate, sshbuf_len(c->output), 863 channel_format_extended_usage(c), sshbuf_len(c->extended), 864 c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan, 865 c->io_want, c->io_ready); 866 return ret; 867 } 868 869 /* 870 * Returns a message describing the currently open forwarded connections, 871 * suitable for sending to the client. The message contains crlf pairs for 872 * newlines. 873 */ 874 char * 875 channel_open_message(struct ssh *ssh) 876 { 877 struct sshbuf *buf; 878 Channel *c; 879 u_int i; 880 int r; 881 char *cp, *ret; 882 883 if ((buf = sshbuf_new()) == NULL) 884 fatal_f("sshbuf_new"); 885 if ((r = sshbuf_putf(buf, 886 "The following connections are open:\r\n")) != 0) 887 fatal_fr(r, "sshbuf_putf"); 888 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 889 c = ssh->chanctxt->channels[i]; 890 if (c == NULL) 891 continue; 892 switch (c->type) { 893 case SSH_CHANNEL_X11_LISTENER: 894 case SSH_CHANNEL_PORT_LISTENER: 895 case SSH_CHANNEL_RPORT_LISTENER: 896 case SSH_CHANNEL_CLOSED: 897 case SSH_CHANNEL_AUTH_SOCKET: 898 case SSH_CHANNEL_ZOMBIE: 899 case SSH_CHANNEL_ABANDONED: 900 case SSH_CHANNEL_MUX_LISTENER: 901 case SSH_CHANNEL_UNIX_LISTENER: 902 case SSH_CHANNEL_RUNIX_LISTENER: 903 continue; 904 case SSH_CHANNEL_LARVAL: 905 case SSH_CHANNEL_OPENING: 906 case SSH_CHANNEL_CONNECTING: 907 case SSH_CHANNEL_DYNAMIC: 908 case SSH_CHANNEL_RDYNAMIC_OPEN: 909 case SSH_CHANNEL_RDYNAMIC_FINISH: 910 case SSH_CHANNEL_OPEN: 911 case SSH_CHANNEL_X11_OPEN: 912 case SSH_CHANNEL_MUX_PROXY: 913 case SSH_CHANNEL_MUX_CLIENT: 914 cp = channel_format_status(c); 915 if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n", 916 c->self, c->remote_name, cp)) != 0) { 917 free(cp); 918 fatal_fr(r, "sshbuf_putf"); 919 } 920 free(cp); 921 continue; 922 default: 923 fatal_f("bad channel type %d", c->type); 924 /* NOTREACHED */ 925 } 926 } 927 if ((ret = sshbuf_dup_string(buf)) == NULL) 928 fatal_f("sshbuf_dup_string"); 929 sshbuf_free(buf); 930 return ret; 931 } 932 933 static void 934 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 935 { 936 int r; 937 938 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 939 (r = sshpkt_put_cstring(ssh, type)) != 0 || 940 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 941 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 942 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 943 fatal_r(r, "%s: channel %i: open", where, c->self); 944 } 945 } 946 947 void 948 channel_send_open(struct ssh *ssh, int id) 949 { 950 Channel *c = channel_lookup(ssh, id); 951 int r; 952 953 if (c == NULL) { 954 logit("channel_send_open: %d: bad id", id); 955 return; 956 } 957 debug2("channel %d: send open", id); 958 open_preamble(ssh, __func__, c, c->ctype); 959 if ((r = sshpkt_send(ssh)) != 0) 960 fatal_fr(r, "channel %i", c->self); 961 } 962 963 void 964 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 965 { 966 Channel *c = channel_lookup(ssh, id); 967 int r; 968 969 if (c == NULL) { 970 logit_f("%d: unknown channel id", id); 971 return; 972 } 973 if (!c->have_remote_id) 974 fatal_f("channel %d: no remote id", c->self); 975 976 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 977 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 978 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 979 (r = sshpkt_put_cstring(ssh, service)) != 0 || 980 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 981 fatal_fr(r, "channel %i", c->self); 982 } 983 } 984 985 void 986 channel_register_status_confirm(struct ssh *ssh, int id, 987 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 988 { 989 struct channel_confirm *cc; 990 Channel *c; 991 992 if ((c = channel_lookup(ssh, id)) == NULL) 993 fatal_f("%d: bad id", id); 994 995 cc = xcalloc(1, sizeof(*cc)); 996 cc->cb = cb; 997 cc->abandon_cb = abandon_cb; 998 cc->ctx = ctx; 999 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 1000 } 1001 1002 void 1003 channel_register_open_confirm(struct ssh *ssh, int id, 1004 channel_open_fn *fn, void *ctx) 1005 { 1006 Channel *c = channel_lookup(ssh, id); 1007 1008 if (c == NULL) { 1009 logit_f("%d: bad id", id); 1010 return; 1011 } 1012 c->open_confirm = fn; 1013 c->open_confirm_ctx = ctx; 1014 } 1015 1016 void 1017 channel_register_cleanup(struct ssh *ssh, int id, 1018 channel_callback_fn *fn, int do_close) 1019 { 1020 Channel *c = channel_by_id(ssh, id); 1021 1022 if (c == NULL) { 1023 logit_f("%d: bad id", id); 1024 return; 1025 } 1026 c->detach_user = fn; 1027 c->detach_close = do_close; 1028 } 1029 1030 void 1031 channel_cancel_cleanup(struct ssh *ssh, int id) 1032 { 1033 Channel *c = channel_by_id(ssh, id); 1034 1035 if (c == NULL) { 1036 logit_f("%d: bad id", id); 1037 return; 1038 } 1039 c->detach_user = NULL; 1040 c->detach_close = 0; 1041 } 1042 1043 void 1044 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 1045 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 1046 { 1047 Channel *c = channel_lookup(ssh, id); 1048 1049 if (c == NULL) { 1050 logit_f("%d: bad id", id); 1051 return; 1052 } 1053 c->input_filter = ifn; 1054 c->output_filter = ofn; 1055 c->filter_ctx = ctx; 1056 c->filter_cleanup = cfn; 1057 } 1058 1059 void 1060 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 1061 int extusage, int nonblock, int is_tty, u_int window_max) 1062 { 1063 Channel *c = channel_lookup(ssh, id); 1064 int r; 1065 1066 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 1067 fatal("channel_activate for non-larval channel %d.", id); 1068 if (!c->have_remote_id) 1069 fatal_f("channel %d: no remote id", c->self); 1070 1071 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 1072 c->type = SSH_CHANNEL_OPEN; 1073 c->local_window = c->local_window_max = window_max; 1074 1075 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 1076 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1077 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1078 (r = sshpkt_send(ssh)) != 0) 1079 fatal_fr(r, "channel %i", c->self); 1080 } 1081 1082 static void 1083 channel_pre_listener(struct ssh *ssh, Channel *c) 1084 { 1085 c->io_want = SSH_CHAN_IO_SOCK_R; 1086 } 1087 1088 static void 1089 channel_pre_connecting(struct ssh *ssh, Channel *c) 1090 { 1091 debug3("channel %d: waiting for connection", c->self); 1092 c->io_want = SSH_CHAN_IO_SOCK_W; 1093 } 1094 1095 static void 1096 channel_pre_open(struct ssh *ssh, Channel *c) 1097 { 1098 c->io_want = 0; 1099 if (c->istate == CHAN_INPUT_OPEN && 1100 c->remote_window > 0 && 1101 sshbuf_len(c->input) < c->remote_window && 1102 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1103 c->io_want |= SSH_CHAN_IO_RFD; 1104 if (c->ostate == CHAN_OUTPUT_OPEN || 1105 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1106 if (sshbuf_len(c->output) > 0) { 1107 c->io_want |= SSH_CHAN_IO_WFD; 1108 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1109 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 1110 debug2("channel %d: " 1111 "obuf_empty delayed efd %d/(%zu)", c->self, 1112 c->efd, sshbuf_len(c->extended)); 1113 else 1114 chan_obuf_empty(ssh, c); 1115 } 1116 } 1117 /** XXX check close conditions, too */ 1118 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 1119 c->ostate == CHAN_OUTPUT_CLOSED)) { 1120 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1121 sshbuf_len(c->extended) > 0) 1122 c->io_want |= SSH_CHAN_IO_EFD_W; 1123 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 1124 (c->extended_usage == CHAN_EXTENDED_READ || 1125 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1126 sshbuf_len(c->extended) < c->remote_window) 1127 c->io_want |= SSH_CHAN_IO_EFD_R; 1128 } 1129 /* XXX: What about efd? races? */ 1130 } 1131 1132 /* 1133 * This is a special state for X11 authentication spoofing. An opened X11 1134 * connection (when authentication spoofing is being done) remains in this 1135 * state until the first packet has been completely read. The authentication 1136 * data in that packet is then substituted by the real data if it matches the 1137 * fake data, and the channel is put into normal mode. 1138 * XXX All this happens at the client side. 1139 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1140 */ 1141 static int 1142 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1143 { 1144 struct ssh_channels *sc = ssh->chanctxt; 1145 u_char *ucp; 1146 u_int proto_len, data_len; 1147 1148 /* Is this being called after the refusal deadline? */ 1149 if (sc->x11_refuse_time != 0 && 1150 (u_int)monotime() >= sc->x11_refuse_time) { 1151 verbose("Rejected X11 connection after ForwardX11Timeout " 1152 "expired"); 1153 return -1; 1154 } 1155 1156 /* Check if the fixed size part of the packet is in buffer. */ 1157 if (sshbuf_len(b) < 12) 1158 return 0; 1159 1160 /* Parse the lengths of variable-length fields. */ 1161 ucp = sshbuf_mutable_ptr(b); 1162 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1163 proto_len = 256 * ucp[6] + ucp[7]; 1164 data_len = 256 * ucp[8] + ucp[9]; 1165 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1166 proto_len = ucp[6] + 256 * ucp[7]; 1167 data_len = ucp[8] + 256 * ucp[9]; 1168 } else { 1169 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1170 ucp[0]); 1171 return -1; 1172 } 1173 1174 /* Check if the whole packet is in buffer. */ 1175 if (sshbuf_len(b) < 1176 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1177 return 0; 1178 1179 /* Check if authentication protocol matches. */ 1180 if (proto_len != strlen(sc->x11_saved_proto) || 1181 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1182 debug2("X11 connection uses different authentication protocol."); 1183 return -1; 1184 } 1185 /* Check if authentication data matches our fake data. */ 1186 if (data_len != sc->x11_fake_data_len || 1187 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1188 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1189 debug2("X11 auth data does not match fake data."); 1190 return -1; 1191 } 1192 /* Check fake data length */ 1193 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1194 error("X11 fake_data_len %d != saved_data_len %d", 1195 sc->x11_fake_data_len, sc->x11_saved_data_len); 1196 return -1; 1197 } 1198 /* 1199 * Received authentication protocol and data match 1200 * our fake data. Substitute the fake data with real 1201 * data. 1202 */ 1203 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1204 sc->x11_saved_data, sc->x11_saved_data_len); 1205 return 1; 1206 } 1207 1208 static void 1209 channel_pre_x11_open(struct ssh *ssh, Channel *c) 1210 { 1211 int ret = x11_open_helper(ssh, c->output); 1212 1213 /* c->force_drain = 1; */ 1214 1215 if (ret == 1) { 1216 c->type = SSH_CHANNEL_OPEN; 1217 channel_pre_open(ssh, c); 1218 } else if (ret == -1) { 1219 logit("X11 connection rejected because of wrong authentication."); 1220 debug2("X11 rejected %d i%d/o%d", 1221 c->self, c->istate, c->ostate); 1222 chan_read_failed(ssh, c); 1223 sshbuf_reset(c->input); 1224 chan_ibuf_empty(ssh, c); 1225 sshbuf_reset(c->output); 1226 chan_write_failed(ssh, c); 1227 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1228 } 1229 } 1230 1231 static void 1232 channel_pre_mux_client(struct ssh *ssh, Channel *c) 1233 { 1234 c->io_want = 0; 1235 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1236 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1237 c->io_want |= SSH_CHAN_IO_RFD; 1238 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1239 /* clear buffer immediately (discard any partial packet) */ 1240 sshbuf_reset(c->input); 1241 chan_ibuf_empty(ssh, c); 1242 /* Start output drain. XXX just kill chan? */ 1243 chan_rcvd_oclose(ssh, c); 1244 } 1245 if (c->ostate == CHAN_OUTPUT_OPEN || 1246 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1247 if (sshbuf_len(c->output) > 0) 1248 c->io_want |= SSH_CHAN_IO_WFD; 1249 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1250 chan_obuf_empty(ssh, c); 1251 } 1252 } 1253 1254 /* try to decode a socks4 header */ 1255 static int 1256 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1257 { 1258 const u_char *p; 1259 char *host; 1260 u_int len, have, i, found, need; 1261 char username[256]; 1262 struct { 1263 u_int8_t version; 1264 u_int8_t command; 1265 u_int16_t dest_port; 1266 struct in_addr dest_addr; 1267 } s4_req, s4_rsp; 1268 int r; 1269 1270 debug2("channel %d: decode socks4", c->self); 1271 1272 have = sshbuf_len(input); 1273 len = sizeof(s4_req); 1274 if (have < len) 1275 return 0; 1276 p = sshbuf_ptr(input); 1277 1278 need = 1; 1279 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1280 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1281 debug2("channel %d: socks4a request", c->self); 1282 /* ... and needs an extra string (the hostname) */ 1283 need = 2; 1284 } 1285 /* Check for terminating NUL on the string(s) */ 1286 for (found = 0, i = len; i < have; i++) { 1287 if (p[i] == '\0') { 1288 found++; 1289 if (found == need) 1290 break; 1291 } 1292 if (i > 1024) { 1293 /* the peer is probably sending garbage */ 1294 debug("channel %d: decode socks4: too long", 1295 c->self); 1296 return -1; 1297 } 1298 } 1299 if (found < need) 1300 return 0; 1301 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1302 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1303 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1304 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1305 debug_r(r, "channels %d: decode socks4", c->self); 1306 return -1; 1307 } 1308 have = sshbuf_len(input); 1309 p = sshbuf_ptr(input); 1310 if (memchr(p, '\0', have) == NULL) { 1311 error("channel %d: decode socks4: unterminated user", c->self); 1312 return -1; 1313 } 1314 len = strlen(p); 1315 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1316 len++; /* trailing '\0' */ 1317 strlcpy(username, p, sizeof(username)); 1318 if ((r = sshbuf_consume(input, len)) != 0) 1319 fatal_fr(r, "channel %d: consume", c->self); 1320 free(c->path); 1321 c->path = NULL; 1322 if (need == 1) { /* SOCKS4: one string */ 1323 host = inet_ntoa(s4_req.dest_addr); 1324 c->path = xstrdup(host); 1325 } else { /* SOCKS4A: two strings */ 1326 have = sshbuf_len(input); 1327 p = sshbuf_ptr(input); 1328 if (memchr(p, '\0', have) == NULL) { 1329 error("channel %d: decode socks4a: host not nul " 1330 "terminated", c->self); 1331 return -1; 1332 } 1333 len = strlen(p); 1334 debug2("channel %d: decode socks4a: host %s/%d", 1335 c->self, p, len); 1336 len++; /* trailing '\0' */ 1337 if (len > NI_MAXHOST) { 1338 error("channel %d: hostname \"%.100s\" too long", 1339 c->self, p); 1340 return -1; 1341 } 1342 c->path = xstrdup(p); 1343 if ((r = sshbuf_consume(input, len)) != 0) 1344 fatal_fr(r, "channel %d: consume", c->self); 1345 } 1346 c->host_port = ntohs(s4_req.dest_port); 1347 1348 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1349 c->self, c->path, c->host_port, s4_req.command); 1350 1351 if (s4_req.command != 1) { 1352 debug("channel %d: cannot handle: %s cn %d", 1353 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1354 return -1; 1355 } 1356 s4_rsp.version = 0; /* vn: 0 for reply */ 1357 s4_rsp.command = 90; /* cd: req granted */ 1358 s4_rsp.dest_port = 0; /* ignored */ 1359 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1360 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) 1361 fatal_fr(r, "channel %d: append reply", c->self); 1362 return 1; 1363 } 1364 1365 /* try to decode a socks5 header */ 1366 #define SSH_SOCKS5_AUTHDONE 0x1000 1367 #define SSH_SOCKS5_NOAUTH 0x00 1368 #define SSH_SOCKS5_IPV4 0x01 1369 #define SSH_SOCKS5_DOMAIN 0x03 1370 #define SSH_SOCKS5_IPV6 0x04 1371 #define SSH_SOCKS5_CONNECT 0x01 1372 #define SSH_SOCKS5_SUCCESS 0x00 1373 1374 static int 1375 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1376 { 1377 /* XXX use get/put_u8 instead of trusting struct padding */ 1378 struct { 1379 u_int8_t version; 1380 u_int8_t command; 1381 u_int8_t reserved; 1382 u_int8_t atyp; 1383 } s5_req, s5_rsp; 1384 u_int16_t dest_port; 1385 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1386 const u_char *p; 1387 u_int have, need, i, found, nmethods, addrlen, af; 1388 int r; 1389 1390 debug2("channel %d: decode socks5", c->self); 1391 p = sshbuf_ptr(input); 1392 if (p[0] != 0x05) 1393 return -1; 1394 have = sshbuf_len(input); 1395 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1396 /* format: ver | nmethods | methods */ 1397 if (have < 2) 1398 return 0; 1399 nmethods = p[1]; 1400 if (have < nmethods + 2) 1401 return 0; 1402 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1403 for (found = 0, i = 2; i < nmethods + 2; i++) { 1404 if (p[i] == SSH_SOCKS5_NOAUTH) { 1405 found = 1; 1406 break; 1407 } 1408 } 1409 if (!found) { 1410 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1411 c->self); 1412 return -1; 1413 } 1414 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) 1415 fatal_fr(r, "channel %d: consume", c->self); 1416 /* version, method */ 1417 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1418 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) 1419 fatal_fr(r, "channel %d: append reply", c->self); 1420 c->flags |= SSH_SOCKS5_AUTHDONE; 1421 debug2("channel %d: socks5 auth done", c->self); 1422 return 0; /* need more */ 1423 } 1424 debug2("channel %d: socks5 post auth", c->self); 1425 if (have < sizeof(s5_req)+1) 1426 return 0; /* need more */ 1427 memcpy(&s5_req, p, sizeof(s5_req)); 1428 if (s5_req.version != 0x05 || 1429 s5_req.command != SSH_SOCKS5_CONNECT || 1430 s5_req.reserved != 0x00) { 1431 debug2("channel %d: only socks5 connect supported", c->self); 1432 return -1; 1433 } 1434 switch (s5_req.atyp){ 1435 case SSH_SOCKS5_IPV4: 1436 addrlen = 4; 1437 af = AF_INET; 1438 break; 1439 case SSH_SOCKS5_DOMAIN: 1440 addrlen = p[sizeof(s5_req)]; 1441 af = -1; 1442 break; 1443 case SSH_SOCKS5_IPV6: 1444 addrlen = 16; 1445 af = AF_INET6; 1446 break; 1447 default: 1448 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1449 return -1; 1450 } 1451 need = sizeof(s5_req) + addrlen + 2; 1452 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1453 need++; 1454 if (have < need) 1455 return 0; 1456 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) 1457 fatal_fr(r, "channel %d: consume", c->self); 1458 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1459 /* host string length */ 1460 if ((r = sshbuf_consume(input, 1)) != 0) 1461 fatal_fr(r, "channel %d: consume", c->self); 1462 } 1463 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1464 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1465 debug_r(r, "channel %d: parse addr/port", c->self); 1466 return -1; 1467 } 1468 dest_addr[addrlen] = '\0'; 1469 free(c->path); 1470 c->path = NULL; 1471 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1472 if (addrlen >= NI_MAXHOST) { 1473 error("channel %d: dynamic request: socks5 hostname " 1474 "\"%.100s\" too long", c->self, dest_addr); 1475 return -1; 1476 } 1477 c->path = xstrdup(dest_addr); 1478 } else { 1479 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1480 return -1; 1481 c->path = xstrdup(ntop); 1482 } 1483 c->host_port = ntohs(dest_port); 1484 1485 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1486 c->self, c->path, c->host_port, s5_req.command); 1487 1488 s5_rsp.version = 0x05; 1489 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1490 s5_rsp.reserved = 0; /* ignored */ 1491 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1492 dest_port = 0; /* ignored */ 1493 1494 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1495 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1496 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1497 fatal_fr(r, "channel %d: append reply", c->self); 1498 return 1; 1499 } 1500 1501 Channel * 1502 channel_connect_stdio_fwd(struct ssh *ssh, 1503 const char *host_to_connect, u_short port_to_connect, 1504 int in, int out, int nonblock) 1505 { 1506 Channel *c; 1507 1508 debug_f("%s:%d", host_to_connect, port_to_connect); 1509 1510 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1511 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1512 0, "stdio-forward", nonblock); 1513 1514 c->path = xstrdup(host_to_connect); 1515 c->host_port = port_to_connect; 1516 c->listening_port = 0; 1517 c->force_drain = 1; 1518 1519 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1520 port_open_helper(ssh, c, "direct-tcpip"); 1521 1522 return c; 1523 } 1524 1525 /* dynamic port forwarding */ 1526 static void 1527 channel_pre_dynamic(struct ssh *ssh, Channel *c) 1528 { 1529 const u_char *p; 1530 u_int have; 1531 int ret; 1532 1533 c->io_want = 0; 1534 have = sshbuf_len(c->input); 1535 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1536 /* sshbuf_dump(c->input, stderr); */ 1537 /* check if the fixed size part of the packet is in buffer. */ 1538 if (have < 3) { 1539 /* need more */ 1540 c->io_want |= SSH_CHAN_IO_RFD; 1541 return; 1542 } 1543 /* try to guess the protocol */ 1544 p = sshbuf_ptr(c->input); 1545 /* XXX sshbuf_peek_u8? */ 1546 switch (p[0]) { 1547 case 0x04: 1548 ret = channel_decode_socks4(c, c->input, c->output); 1549 break; 1550 case 0x05: 1551 ret = channel_decode_socks5(c, c->input, c->output); 1552 break; 1553 default: 1554 ret = -1; 1555 break; 1556 } 1557 if (ret < 0) { 1558 chan_mark_dead(ssh, c); 1559 } else if (ret == 0) { 1560 debug2("channel %d: pre_dynamic: need more", c->self); 1561 /* need more */ 1562 c->io_want |= SSH_CHAN_IO_RFD; 1563 if (sshbuf_len(c->output)) 1564 c->io_want |= SSH_CHAN_IO_WFD; 1565 } else { 1566 /* switch to the next state */ 1567 c->type = SSH_CHANNEL_OPENING; 1568 port_open_helper(ssh, c, "direct-tcpip"); 1569 } 1570 } 1571 1572 /* simulate read-error */ 1573 static void 1574 rdynamic_close(struct ssh *ssh, Channel *c) 1575 { 1576 c->type = SSH_CHANNEL_OPEN; 1577 chan_read_failed(ssh, c); 1578 sshbuf_reset(c->input); 1579 chan_ibuf_empty(ssh, c); 1580 sshbuf_reset(c->output); 1581 chan_write_failed(ssh, c); 1582 } 1583 1584 /* reverse dynamic port forwarding */ 1585 static void 1586 channel_before_prepare_io_rdynamic(struct ssh *ssh, Channel *c) 1587 { 1588 const u_char *p; 1589 u_int have, len; 1590 int r, ret; 1591 1592 have = sshbuf_len(c->output); 1593 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1594 /* sshbuf_dump(c->output, stderr); */ 1595 /* EOF received */ 1596 if (c->flags & CHAN_EOF_RCVD) { 1597 if ((r = sshbuf_consume(c->output, have)) != 0) 1598 fatal_fr(r, "channel %d: consume", c->self); 1599 rdynamic_close(ssh, c); 1600 return; 1601 } 1602 /* check if the fixed size part of the packet is in buffer. */ 1603 if (have < 3) 1604 return; 1605 /* try to guess the protocol */ 1606 p = sshbuf_ptr(c->output); 1607 switch (p[0]) { 1608 case 0x04: 1609 /* switch input/output for reverse forwarding */ 1610 ret = channel_decode_socks4(c, c->output, c->input); 1611 break; 1612 case 0x05: 1613 ret = channel_decode_socks5(c, c->output, c->input); 1614 break; 1615 default: 1616 ret = -1; 1617 break; 1618 } 1619 if (ret < 0) { 1620 rdynamic_close(ssh, c); 1621 } else if (ret == 0) { 1622 debug2("channel %d: pre_rdynamic: need more", c->self); 1623 /* send socks request to peer */ 1624 len = sshbuf_len(c->input); 1625 if (len > 0 && len < c->remote_window) { 1626 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1627 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1628 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1629 (r = sshpkt_send(ssh)) != 0) { 1630 fatal_fr(r, "channel %i: rdynamic", c->self); 1631 } 1632 if ((r = sshbuf_consume(c->input, len)) != 0) 1633 fatal_fr(r, "channel %d: consume", c->self); 1634 c->remote_window -= len; 1635 } 1636 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1637 /* the connect failed */ 1638 rdynamic_close(ssh, c); 1639 } 1640 } 1641 1642 /* This is our fake X11 server socket. */ 1643 static void 1644 channel_post_x11_listener(struct ssh *ssh, Channel *c) 1645 { 1646 Channel *nc; 1647 struct sockaddr_storage addr; 1648 int r, newsock, oerrno, remote_port; 1649 socklen_t addrlen; 1650 char buf[16384], *remote_ipaddr; 1651 1652 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1653 return; 1654 1655 debug("X11 connection requested."); 1656 addrlen = sizeof(addr); 1657 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1658 if (c->single_connection) { 1659 oerrno = errno; 1660 debug2("single_connection: closing X11 listener."); 1661 channel_close_fd(ssh, c, &c->sock); 1662 chan_mark_dead(ssh, c); 1663 errno = oerrno; 1664 } 1665 if (newsock == -1) { 1666 if (errno != EINTR && errno != EWOULDBLOCK && 1667 errno != ECONNABORTED) 1668 error("accept: %.100s", strerror(errno)); 1669 if (errno == EMFILE || errno == ENFILE) 1670 c->notbefore = monotime() + 1; 1671 return; 1672 } 1673 set_nodelay(newsock); 1674 remote_ipaddr = get_peer_ipaddr(newsock); 1675 remote_port = get_peer_port(newsock); 1676 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1677 remote_ipaddr, remote_port); 1678 1679 nc = channel_new(ssh, "accepted x11 socket", 1680 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1681 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1682 open_preamble(ssh, __func__, nc, "x11"); 1683 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1684 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1685 fatal_fr(r, "channel %i: reply", c->self); 1686 } 1687 if ((r = sshpkt_send(ssh)) != 0) 1688 fatal_fr(r, "channel %i: send", c->self); 1689 free(remote_ipaddr); 1690 } 1691 1692 static void 1693 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1694 { 1695 char *local_ipaddr = get_local_ipaddr(c->sock); 1696 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1697 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1698 int remote_port = get_peer_port(c->sock); 1699 int r; 1700 1701 if (remote_port == -1) { 1702 /* Fake addr/port to appease peers that validate it (Tectia) */ 1703 free(remote_ipaddr); 1704 remote_ipaddr = xstrdup("127.0.0.1"); 1705 remote_port = 65535; 1706 } 1707 1708 free(c->remote_name); 1709 xasprintf(&c->remote_name, 1710 "%s: listening port %d for %.100s port %d, " 1711 "connect from %.200s port %d to %.100s port %d", 1712 rtype, c->listening_port, c->path, c->host_port, 1713 remote_ipaddr, remote_port, local_ipaddr, local_port); 1714 1715 open_preamble(ssh, __func__, c, rtype); 1716 if (strcmp(rtype, "direct-tcpip") == 0) { 1717 /* target host, port */ 1718 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1719 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) 1720 fatal_fr(r, "channel %i: reply", c->self); 1721 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1722 /* target path */ 1723 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1724 fatal_fr(r, "channel %i: reply", c->self); 1725 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1726 /* listen path */ 1727 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) 1728 fatal_fr(r, "channel %i: reply", c->self); 1729 } else { 1730 /* listen address, port */ 1731 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1732 (r = sshpkt_put_u32(ssh, local_port)) != 0) 1733 fatal_fr(r, "channel %i: reply", c->self); 1734 } 1735 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1736 /* reserved for future owner/mode info */ 1737 if ((r = sshpkt_put_cstring(ssh, "")) != 0) 1738 fatal_fr(r, "channel %i: reply", c->self); 1739 } else { 1740 /* originator host and port */ 1741 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1742 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) 1743 fatal_fr(r, "channel %i: reply", c->self); 1744 } 1745 if ((r = sshpkt_send(ssh)) != 0) 1746 fatal_fr(r, "channel %i: send", c->self); 1747 free(remote_ipaddr); 1748 free(local_ipaddr); 1749 } 1750 1751 void 1752 channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time) 1753 { 1754 ssh->chanctxt->x11_refuse_time = refuse_time; 1755 } 1756 1757 /* 1758 * This socket is listening for connections to a forwarded TCP/IP port. 1759 */ 1760 static void 1761 channel_post_port_listener(struct ssh *ssh, Channel *c) 1762 { 1763 Channel *nc; 1764 struct sockaddr_storage addr; 1765 int newsock, nextstate; 1766 socklen_t addrlen; 1767 char *rtype; 1768 1769 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1770 return; 1771 1772 debug("Connection to port %d forwarding to %.100s port %d requested.", 1773 c->listening_port, c->path, c->host_port); 1774 1775 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1776 nextstate = SSH_CHANNEL_OPENING; 1777 rtype = "forwarded-tcpip"; 1778 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1779 nextstate = SSH_CHANNEL_OPENING; 1780 rtype = "forwarded-streamlocal@openssh.com"; 1781 } else if (c->host_port == PORT_STREAMLOCAL) { 1782 nextstate = SSH_CHANNEL_OPENING; 1783 rtype = "direct-streamlocal@openssh.com"; 1784 } else if (c->host_port == 0) { 1785 nextstate = SSH_CHANNEL_DYNAMIC; 1786 rtype = "dynamic-tcpip"; 1787 } else { 1788 nextstate = SSH_CHANNEL_OPENING; 1789 rtype = "direct-tcpip"; 1790 } 1791 1792 addrlen = sizeof(addr); 1793 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1794 if (newsock == -1) { 1795 if (errno != EINTR && errno != EWOULDBLOCK && 1796 errno != ECONNABORTED) 1797 error("accept: %.100s", strerror(errno)); 1798 if (errno == EMFILE || errno == ENFILE) 1799 c->notbefore = monotime() + 1; 1800 return; 1801 } 1802 if (c->host_port != PORT_STREAMLOCAL) 1803 set_nodelay(newsock); 1804 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1805 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1806 nc->listening_port = c->listening_port; 1807 nc->host_port = c->host_port; 1808 if (c->path != NULL) 1809 nc->path = xstrdup(c->path); 1810 1811 if (nextstate != SSH_CHANNEL_DYNAMIC) 1812 port_open_helper(ssh, nc, rtype); 1813 } 1814 1815 /* 1816 * This is the authentication agent socket listening for connections from 1817 * clients. 1818 */ 1819 static void 1820 channel_post_auth_listener(struct ssh *ssh, Channel *c) 1821 { 1822 Channel *nc; 1823 int r, newsock; 1824 struct sockaddr_storage addr; 1825 socklen_t addrlen; 1826 1827 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 1828 return; 1829 1830 addrlen = sizeof(addr); 1831 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1832 if (newsock == -1) { 1833 error("accept from auth socket: %.100s", strerror(errno)); 1834 if (errno == EMFILE || errno == ENFILE) 1835 c->notbefore = monotime() + 1; 1836 return; 1837 } 1838 nc = channel_new(ssh, "accepted auth socket", 1839 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1840 c->local_window_max, c->local_maxpacket, 1841 0, "accepted auth socket", 1); 1842 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1843 if ((r = sshpkt_send(ssh)) != 0) 1844 fatal_fr(r, "channel %i", c->self); 1845 } 1846 1847 static void 1848 channel_post_connecting(struct ssh *ssh, Channel *c) 1849 { 1850 int err = 0, sock, isopen, r; 1851 socklen_t sz = sizeof(err); 1852 1853 if ((c->io_ready & SSH_CHAN_IO_SOCK_W) == 0) 1854 return; 1855 if (!c->have_remote_id) 1856 fatal_f("channel %d: no remote id", c->self); 1857 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1858 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1859 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) == -1) { 1860 err = errno; 1861 error("getsockopt SO_ERROR failed"); 1862 } 1863 if (err == 0) { 1864 debug("channel %d: connected to %s port %d", 1865 c->self, c->connect_ctx.host, c->connect_ctx.port); 1866 channel_connect_ctx_free(&c->connect_ctx); 1867 c->type = SSH_CHANNEL_OPEN; 1868 if (isopen) { 1869 /* no message necessary */ 1870 } else { 1871 if ((r = sshpkt_start(ssh, 1872 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1873 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1874 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1875 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1876 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1877 (r = sshpkt_send(ssh)) != 0) 1878 fatal_fr(r, "channel %i open confirm", c->self); 1879 } 1880 } else { 1881 debug("channel %d: connection failed: %s", 1882 c->self, strerror(err)); 1883 /* Try next address, if any */ 1884 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1885 close(c->sock); 1886 c->sock = c->rfd = c->wfd = sock; 1887 return; 1888 } 1889 /* Exhausted all addresses */ 1890 error("connect_to %.100s port %d: failed.", 1891 c->connect_ctx.host, c->connect_ctx.port); 1892 channel_connect_ctx_free(&c->connect_ctx); 1893 if (isopen) { 1894 rdynamic_close(ssh, c); 1895 } else { 1896 if ((r = sshpkt_start(ssh, 1897 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1898 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1899 (r = sshpkt_put_u32(ssh, 1900 SSH2_OPEN_CONNECT_FAILED)) != 0 || 1901 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 1902 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1903 (r = sshpkt_send(ssh)) != 0) 1904 fatal_fr(r, "channel %i: failure", c->self); 1905 chan_mark_dead(ssh, c); 1906 } 1907 } 1908 } 1909 1910 static int 1911 channel_handle_rfd(struct ssh *ssh, Channel *c) 1912 { 1913 char buf[CHAN_RBUF]; 1914 ssize_t len; 1915 int r; 1916 size_t have, avail, maxlen = CHANNEL_MAX_READ; 1917 1918 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 1919 return 1; /* Shouldn't happen */ 1920 if ((avail = sshbuf_avail(c->input)) == 0) 1921 return 1; /* Shouldn't happen */ 1922 1923 /* 1924 * For "simple" channels (i.e. not datagram or filtered), we can 1925 * read directly to the channel buffer. 1926 */ 1927 if (c->input_filter == NULL && !c->datagram) { 1928 /* Only OPEN channels have valid rwin */ 1929 if (c->type == SSH_CHANNEL_OPEN) { 1930 if ((have = sshbuf_len(c->input)) >= c->remote_window) 1931 return 1; /* shouldn't happen */ 1932 if (maxlen > c->remote_window - have) 1933 maxlen = c->remote_window - have; 1934 } 1935 if (maxlen > avail) 1936 maxlen = avail; 1937 if ((r = sshbuf_read(c->rfd, c->input, maxlen, NULL)) != 0) { 1938 if (errno == EINTR || errno == EAGAIN) 1939 return 1; 1940 debug2("channel %d: read failed rfd %d maxlen %zu: %s", 1941 c->self, c->rfd, maxlen, ssh_err(r)); 1942 goto rfail; 1943 } 1944 return 1; 1945 } 1946 1947 len = read(c->rfd, buf, sizeof(buf)); 1948 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 1949 return 1; 1950 if (len <= 0) { 1951 debug2("channel %d: read<=0 rfd %d len %zd: %s", 1952 c->self, c->rfd, len, 1953 len == 0 ? "closed" : strerror(errno)); 1954 rfail: 1955 if (c->type != SSH_CHANNEL_OPEN) { 1956 debug2("channel %d: not open", c->self); 1957 chan_mark_dead(ssh, c); 1958 return -1; 1959 } else { 1960 chan_read_failed(ssh, c); 1961 } 1962 return -1; 1963 } 1964 if (c->input_filter != NULL) { 1965 if (c->input_filter(ssh, c, buf, len) == -1) { 1966 debug2("channel %d: filter stops", c->self); 1967 chan_read_failed(ssh, c); 1968 } 1969 } else if (c->datagram) { 1970 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 1971 fatal_fr(r, "channel %i: put datagram", c->self); 1972 } 1973 return 1; 1974 } 1975 1976 static int 1977 channel_handle_wfd(struct ssh *ssh, Channel *c) 1978 { 1979 struct termios tio; 1980 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 1981 size_t dlen, olen = 0; 1982 int r, len; 1983 1984 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 1985 return 1; 1986 if (sshbuf_len(c->output) == 0) 1987 return 1; 1988 1989 /* Send buffered output data to the socket. */ 1990 olen = sshbuf_len(c->output); 1991 if (c->output_filter != NULL) { 1992 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 1993 debug2("channel %d: filter stops", c->self); 1994 if (c->type != SSH_CHANNEL_OPEN) 1995 chan_mark_dead(ssh, c); 1996 else 1997 chan_write_failed(ssh, c); 1998 return -1; 1999 } 2000 } else if (c->datagram) { 2001 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 2002 fatal_fr(r, "channel %i: get datagram", c->self); 2003 buf = data; 2004 } else { 2005 buf = data = sshbuf_mutable_ptr(c->output); 2006 dlen = sshbuf_len(c->output); 2007 } 2008 2009 if (c->datagram) { 2010 /* ignore truncated writes, datagrams might get lost */ 2011 len = write(c->wfd, buf, dlen); 2012 free(data); 2013 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2014 return 1; 2015 if (len <= 0) 2016 goto write_fail; 2017 goto out; 2018 } 2019 2020 len = write(c->wfd, buf, dlen); 2021 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2022 return 1; 2023 if (len <= 0) { 2024 write_fail: 2025 if (c->type != SSH_CHANNEL_OPEN) { 2026 debug2("channel %d: not open", c->self); 2027 chan_mark_dead(ssh, c); 2028 return -1; 2029 } else { 2030 chan_write_failed(ssh, c); 2031 } 2032 return -1; 2033 } 2034 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 2035 if (tcgetattr(c->wfd, &tio) == 0 && 2036 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 2037 /* 2038 * Simulate echo to reduce the impact of 2039 * traffic analysis. We need to match the 2040 * size of a SSH2_MSG_CHANNEL_DATA message 2041 * (4 byte channel id + buf) 2042 */ 2043 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 2044 (r = sshpkt_send(ssh)) != 0) 2045 fatal_fr(r, "channel %i: ignore", c->self); 2046 } 2047 } 2048 if ((r = sshbuf_consume(c->output, len)) != 0) 2049 fatal_fr(r, "channel %i: consume", c->self); 2050 out: 2051 c->local_consumed += olen - sshbuf_len(c->output); 2052 2053 return 1; 2054 } 2055 2056 static int 2057 channel_handle_efd_write(struct ssh *ssh, Channel *c) 2058 { 2059 int r; 2060 ssize_t len; 2061 2062 if ((c->io_ready & SSH_CHAN_IO_EFD_W) == 0) 2063 return 1; 2064 if (sshbuf_len(c->extended) == 0) 2065 return 1; 2066 2067 len = write(c->efd, sshbuf_ptr(c->extended), 2068 sshbuf_len(c->extended)); 2069 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 2070 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2071 return 1; 2072 if (len <= 0) { 2073 debug2("channel %d: closing write-efd %d", c->self, c->efd); 2074 channel_close_fd(ssh, c, &c->efd); 2075 } else { 2076 if ((r = sshbuf_consume(c->extended, len)) != 0) 2077 fatal_fr(r, "channel %i: consume", c->self); 2078 c->local_consumed += len; 2079 } 2080 return 1; 2081 } 2082 2083 static int 2084 channel_handle_efd_read(struct ssh *ssh, Channel *c) 2085 { 2086 char buf[CHAN_RBUF]; 2087 int r; 2088 ssize_t len; 2089 2090 if ((c->io_ready & SSH_CHAN_IO_EFD_R) == 0) 2091 return 1; 2092 2093 len = read(c->efd, buf, sizeof(buf)); 2094 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 2095 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2096 return 1; 2097 if (len <= 0) { 2098 debug2("channel %d: closing read-efd %d", c->self, c->efd); 2099 channel_close_fd(ssh, c, &c->efd); 2100 } else if (c->extended_usage == CHAN_EXTENDED_IGNORE) 2101 debug3("channel %d: discard efd", c->self); 2102 else if ((r = sshbuf_put(c->extended, buf, len)) != 0) 2103 fatal_fr(r, "channel %i: append", c->self); 2104 return 1; 2105 } 2106 2107 static int 2108 channel_handle_efd(struct ssh *ssh, Channel *c) 2109 { 2110 if (c->efd == -1) 2111 return 1; 2112 2113 /** XXX handle drain efd, too */ 2114 2115 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2116 return channel_handle_efd_write(ssh, c); 2117 else if (c->extended_usage == CHAN_EXTENDED_READ || 2118 c->extended_usage == CHAN_EXTENDED_IGNORE) 2119 return channel_handle_efd_read(ssh, c); 2120 2121 return 1; 2122 } 2123 2124 static int 2125 channel_check_window(struct ssh *ssh, Channel *c) 2126 { 2127 int r; 2128 2129 if (c->type == SSH_CHANNEL_OPEN && 2130 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2131 ((c->local_window_max - c->local_window > 2132 c->local_maxpacket*3) || 2133 c->local_window < c->local_window_max/2) && 2134 c->local_consumed > 0) { 2135 if (!c->have_remote_id) 2136 fatal_f("channel %d: no remote id", c->self); 2137 if ((r = sshpkt_start(ssh, 2138 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2139 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2140 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2141 (r = sshpkt_send(ssh)) != 0) { 2142 fatal_fr(r, "channel %i", c->self); 2143 } 2144 debug2("channel %d: window %d sent adjust %d", c->self, 2145 c->local_window, c->local_consumed); 2146 c->local_window += c->local_consumed; 2147 c->local_consumed = 0; 2148 } 2149 return 1; 2150 } 2151 2152 static void 2153 channel_post_open(struct ssh *ssh, Channel *c) 2154 { 2155 channel_handle_rfd(ssh, c); 2156 channel_handle_wfd(ssh, c); 2157 channel_handle_efd(ssh, c); 2158 channel_check_window(ssh, c); 2159 } 2160 2161 static u_int 2162 read_mux(struct ssh *ssh, Channel *c, u_int need) 2163 { 2164 char buf[CHAN_RBUF]; 2165 ssize_t len; 2166 u_int rlen; 2167 int r; 2168 2169 if (sshbuf_len(c->input) < need) { 2170 rlen = need - sshbuf_len(c->input); 2171 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2172 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2173 return sshbuf_len(c->input); 2174 if (len <= 0) { 2175 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2176 c->self, c->rfd, len); 2177 chan_read_failed(ssh, c); 2178 return 0; 2179 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) 2180 fatal_fr(r, "channel %i: append", c->self); 2181 } 2182 return sshbuf_len(c->input); 2183 } 2184 2185 static void 2186 channel_post_mux_client_read(struct ssh *ssh, Channel *c) 2187 { 2188 u_int need; 2189 2190 if ((c->io_ready & SSH_CHAN_IO_RFD) == 0) 2191 return; 2192 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2193 return; 2194 if (c->mux_pause) 2195 return; 2196 2197 /* 2198 * Don't not read past the precise end of packets to 2199 * avoid disrupting fd passing. 2200 */ 2201 if (read_mux(ssh, c, 4) < 4) /* read header */ 2202 return; 2203 /* XXX sshbuf_peek_u32 */ 2204 need = PEEK_U32(sshbuf_ptr(c->input)); 2205 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2206 if (need > CHANNEL_MUX_MAX_PACKET) { 2207 debug2("channel %d: packet too big %u > %u", 2208 c->self, CHANNEL_MUX_MAX_PACKET, need); 2209 chan_rcvd_oclose(ssh, c); 2210 return; 2211 } 2212 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2213 return; 2214 if (c->mux_rcb(ssh, c) != 0) { 2215 debug("channel %d: mux_rcb failed", c->self); 2216 chan_mark_dead(ssh, c); 2217 return; 2218 } 2219 } 2220 2221 static void 2222 channel_post_mux_client_write(struct ssh *ssh, Channel *c) 2223 { 2224 ssize_t len; 2225 int r; 2226 2227 if ((c->io_ready & SSH_CHAN_IO_WFD) == 0) 2228 return; 2229 if (sshbuf_len(c->output) == 0) 2230 return; 2231 2232 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2233 if (len == -1 && (errno == EINTR || errno == EAGAIN)) 2234 return; 2235 if (len <= 0) { 2236 chan_mark_dead(ssh, c); 2237 return; 2238 } 2239 if ((r = sshbuf_consume(c->output, len)) != 0) 2240 fatal_fr(r, "channel %i: consume", c->self); 2241 } 2242 2243 static void 2244 channel_post_mux_client(struct ssh *ssh, Channel *c) 2245 { 2246 channel_post_mux_client_read(ssh, c); 2247 channel_post_mux_client_write(ssh, c); 2248 } 2249 2250 static void 2251 channel_post_mux_listener(struct ssh *ssh, Channel *c) 2252 { 2253 Channel *nc; 2254 struct sockaddr_storage addr; 2255 socklen_t addrlen; 2256 int newsock; 2257 uid_t euid; 2258 gid_t egid; 2259 2260 if ((c->io_ready & SSH_CHAN_IO_SOCK_R) == 0) 2261 return; 2262 2263 debug("multiplexing control connection"); 2264 2265 /* 2266 * Accept connection on control socket 2267 */ 2268 memset(&addr, 0, sizeof(addr)); 2269 addrlen = sizeof(addr); 2270 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2271 &addrlen)) == -1) { 2272 error_f("accept: %s", strerror(errno)); 2273 if (errno == EMFILE || errno == ENFILE) 2274 c->notbefore = monotime() + 1; 2275 return; 2276 } 2277 2278 if (getpeereid(newsock, &euid, &egid) == -1) { 2279 error_f("getpeereid failed: %s", strerror(errno)); 2280 close(newsock); 2281 return; 2282 } 2283 if ((euid != 0) && (getuid() != euid)) { 2284 error("multiplex uid mismatch: peer euid %u != uid %u", 2285 (u_int)euid, (u_int)getuid()); 2286 close(newsock); 2287 return; 2288 } 2289 nc = channel_new(ssh, "multiplex client", SSH_CHANNEL_MUX_CLIENT, 2290 newsock, newsock, -1, c->local_window_max, 2291 c->local_maxpacket, 0, "mux-control", 1); 2292 nc->mux_rcb = c->mux_rcb; 2293 debug3_f("new mux channel %d fd %d", nc->self, nc->sock); 2294 /* establish state */ 2295 nc->mux_rcb(ssh, nc); 2296 /* mux state transitions must not elicit protocol messages */ 2297 nc->flags |= CHAN_LOCAL; 2298 } 2299 2300 static void 2301 channel_handler_init(struct ssh_channels *sc) 2302 { 2303 chan_fn **pre, **post; 2304 2305 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2306 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2307 fatal_f("allocation failed"); 2308 2309 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2310 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2311 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2312 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2313 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2314 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2315 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2316 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2317 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2318 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2319 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2320 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2321 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2322 2323 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2324 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2325 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2326 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2327 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2328 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2329 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2330 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2331 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2332 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2333 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2334 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2335 2336 sc->channel_pre = pre; 2337 sc->channel_post = post; 2338 } 2339 2340 /* gc dead channels */ 2341 static void 2342 channel_garbage_collect(struct ssh *ssh, Channel *c) 2343 { 2344 if (c == NULL) 2345 return; 2346 if (c->detach_user != NULL) { 2347 if (!chan_is_dead(ssh, c, c->detach_close)) 2348 return; 2349 2350 debug2("channel %d: gc: notify user", c->self); 2351 c->detach_user(ssh, c->self, NULL); 2352 /* if we still have a callback */ 2353 if (c->detach_user != NULL) 2354 return; 2355 debug2("channel %d: gc: user detached", c->self); 2356 } 2357 if (!chan_is_dead(ssh, c, 1)) 2358 return; 2359 debug2("channel %d: garbage collecting", c->self); 2360 channel_free(ssh, c); 2361 } 2362 2363 enum channel_table { CHAN_PRE, CHAN_POST }; 2364 2365 static void 2366 channel_handler(struct ssh *ssh, int table, time_t *unpause_secs) 2367 { 2368 struct ssh_channels *sc = ssh->chanctxt; 2369 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2370 u_int i, oalloc; 2371 Channel *c; 2372 time_t now; 2373 2374 now = monotime(); 2375 if (unpause_secs != NULL) 2376 *unpause_secs = 0; 2377 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2378 c = sc->channels[i]; 2379 if (c == NULL) 2380 continue; 2381 /* Try to keep IO going while rekeying */ 2382 if (ssh_packet_is_rekeying(ssh) && c->type != SSH_CHANNEL_OPEN) 2383 continue; 2384 if (c->delayed) { 2385 if (table == CHAN_PRE) 2386 c->delayed = 0; 2387 else 2388 continue; 2389 } 2390 if (ftab[c->type] != NULL) { 2391 /* 2392 * Run handlers that are not paused. 2393 */ 2394 if (c->notbefore <= now) 2395 (*ftab[c->type])(ssh, c); 2396 else if (unpause_secs != NULL) { 2397 /* 2398 * Collect the time that the earliest 2399 * channel comes off pause. 2400 */ 2401 debug3_f("chan %d: skip for %d more " 2402 "seconds", c->self, 2403 (int)(c->notbefore - now)); 2404 if (*unpause_secs == 0 || 2405 (c->notbefore - now) < *unpause_secs) 2406 *unpause_secs = c->notbefore - now; 2407 } 2408 } 2409 channel_garbage_collect(ssh, c); 2410 } 2411 if (unpause_secs != NULL && *unpause_secs != 0) 2412 debug3_f("first channel unpauses in %d seconds", 2413 (int)*unpause_secs); 2414 } 2415 2416 /* 2417 * Create sockets before preparing IO. 2418 * This is necessary for things that need to happen after reading 2419 * the network-input but need to be completed before IO event setup, e.g. 2420 * because they may create new channels. 2421 */ 2422 static void 2423 channel_before_prepare_io(struct ssh *ssh) 2424 { 2425 struct ssh_channels *sc = ssh->chanctxt; 2426 Channel *c; 2427 u_int i, oalloc; 2428 2429 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2430 c = sc->channels[i]; 2431 if (c == NULL) 2432 continue; 2433 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2434 channel_before_prepare_io_rdynamic(ssh, c); 2435 } 2436 } 2437 2438 static void 2439 dump_channel_poll(const char *func, const char *what, Channel *c, 2440 u_int pollfd_offset, struct pollfd *pfd) 2441 { 2442 #ifdef DEBUG_CHANNEL_POLL 2443 debug3("%s: channel %d: %s r%d w%d e%d s%d c->pfds [ %d %d %d %d ] " 2444 "io_want 0x%02x io_ready 0x%02x pfd[%u].fd=%d " 2445 "pfd.ev 0x%02x pfd.rev 0x%02x", func, c->self, what, 2446 c->rfd, c->wfd, c->efd, c->sock, 2447 c->pfds[0], c->pfds[1], c->pfds[2], c->pfds[3], 2448 c->io_want, c->io_ready, 2449 pollfd_offset, pfd->fd, pfd->events, pfd->revents); 2450 #endif 2451 } 2452 2453 /* Prepare pollfd entries for a single channel */ 2454 static void 2455 channel_prepare_pollfd(Channel *c, u_int *next_pollfd, 2456 struct pollfd *pfd, u_int npfd) 2457 { 2458 u_int ev, p = *next_pollfd; 2459 2460 if (c == NULL) 2461 return; 2462 if (p + 4 > npfd) { 2463 /* Shouldn't happen */ 2464 fatal_f("channel %d: bad pfd offset %u (max %u)", 2465 c->self, p, npfd); 2466 } 2467 c->pfds[0] = c->pfds[1] = c->pfds[2] = c->pfds[3] = -1; 2468 /* 2469 * prepare c->rfd 2470 * 2471 * This is a special case, since c->rfd might be the same as 2472 * c->wfd, c->efd and/or c->sock. Handle those here if they want 2473 * IO too. 2474 */ 2475 if (c->rfd != -1) { 2476 ev = 0; 2477 if ((c->io_want & SSH_CHAN_IO_RFD) != 0) 2478 ev |= POLLIN; 2479 /* rfd == wfd */ 2480 if (c->wfd == c->rfd) { 2481 if ((c->io_want & SSH_CHAN_IO_WFD) != 0) 2482 ev |= POLLOUT; 2483 } 2484 /* rfd == efd */ 2485 if (c->efd == c->rfd) { 2486 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2487 ev |= POLLIN; 2488 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2489 ev |= POLLOUT; 2490 } 2491 /* rfd == sock */ 2492 if (c->sock == c->rfd) { 2493 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2494 ev |= POLLIN; 2495 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2496 ev |= POLLOUT; 2497 } 2498 /* Pack a pfd entry if any event armed for this fd */ 2499 if (ev != 0) { 2500 c->pfds[0] = p; 2501 pfd[p].fd = c->rfd; 2502 pfd[p].events = ev; 2503 dump_channel_poll(__func__, "rfd", c, p, &pfd[p]); 2504 p++; 2505 } 2506 } 2507 /* prepare c->wfd if wanting IO and not already handled above */ 2508 if (c->wfd != -1 && c->rfd != c->wfd) { 2509 ev = 0; 2510 if ((c->io_want & SSH_CHAN_IO_WFD)) 2511 ev |= POLLOUT; 2512 /* Pack a pfd entry if any event armed for this fd */ 2513 if (ev != 0) { 2514 c->pfds[1] = p; 2515 pfd[p].fd = c->wfd; 2516 pfd[p].events = ev; 2517 dump_channel_poll(__func__, "wfd", c, p, &pfd[p]); 2518 p++; 2519 } 2520 } 2521 /* prepare c->efd if wanting IO and not already handled above */ 2522 if (c->efd != -1 && c->rfd != c->efd) { 2523 ev = 0; 2524 if ((c->io_want & SSH_CHAN_IO_EFD_R) != 0) 2525 ev |= POLLIN; 2526 if ((c->io_want & SSH_CHAN_IO_EFD_W) != 0) 2527 ev |= POLLOUT; 2528 /* Pack a pfd entry if any event armed for this fd */ 2529 if (ev != 0) { 2530 c->pfds[2] = p; 2531 pfd[p].fd = c->efd; 2532 pfd[p].events = ev; 2533 dump_channel_poll(__func__, "efd", c, p, &pfd[p]); 2534 p++; 2535 } 2536 } 2537 /* prepare c->sock if wanting IO and not already handled above */ 2538 if (c->sock != -1 && c->rfd != c->sock) { 2539 ev = 0; 2540 if ((c->io_want & SSH_CHAN_IO_SOCK_R) != 0) 2541 ev |= POLLIN; 2542 if ((c->io_want & SSH_CHAN_IO_SOCK_W) != 0) 2543 ev |= POLLOUT; 2544 /* Pack a pfd entry if any event armed for this fd */ 2545 if (ev != 0) { 2546 c->pfds[3] = p; 2547 pfd[p].fd = c->sock; 2548 pfd[p].events = 0; 2549 dump_channel_poll(__func__, "sock", c, p, &pfd[p]); 2550 p++; 2551 } 2552 } 2553 *next_pollfd = p; 2554 } 2555 2556 /* * Allocate/prepare poll structure */ 2557 void 2558 channel_prepare_poll(struct ssh *ssh, struct pollfd **pfdp, u_int *npfd_allocp, 2559 u_int *npfd_activep, u_int npfd_reserved, time_t *minwait_secs) 2560 { 2561 struct ssh_channels *sc = ssh->chanctxt; 2562 u_int i, oalloc, p, npfd = npfd_reserved; 2563 2564 channel_before_prepare_io(ssh); /* might create a new channel */ 2565 /* clear out I/O flags from last poll */ 2566 for (i = 0; i < sc->channels_alloc; i++) { 2567 if (sc->channels[i] == NULL) 2568 continue; 2569 sc->channels[i]->io_want = sc->channels[i]->io_ready = 0; 2570 } 2571 /* Allocate 4x pollfd for each channel (rfd, wfd, efd, sock) */ 2572 if (sc->channels_alloc >= (INT_MAX / 4) - npfd_reserved) 2573 fatal_f("too many channels"); /* shouldn't happen */ 2574 npfd += sc->channels_alloc * 4; 2575 if (npfd > *npfd_allocp) { 2576 *pfdp = xrecallocarray(*pfdp, *npfd_allocp, 2577 npfd, sizeof(**pfdp)); 2578 *npfd_allocp = npfd; 2579 } 2580 *npfd_activep = npfd_reserved; 2581 oalloc = sc->channels_alloc; 2582 2583 channel_handler(ssh, CHAN_PRE, minwait_secs); 2584 2585 if (oalloc != sc->channels_alloc) { 2586 /* shouldn't happen */ 2587 fatal_f("channels_alloc changed during CHAN_PRE " 2588 "(was %u, now %u)", oalloc, sc->channels_alloc); 2589 } 2590 2591 /* Prepare pollfd */ 2592 p = npfd_reserved; 2593 for (i = 0; i < sc->channels_alloc; i++) 2594 channel_prepare_pollfd(sc->channels[i], &p, *pfdp, npfd); 2595 *npfd_activep = p; 2596 } 2597 2598 static void 2599 fd_ready(Channel *c, int p, struct pollfd *pfds, u_int npfd, int fd, 2600 const char *what, u_int revents_mask, u_int ready) 2601 { 2602 struct pollfd *pfd = &pfds[p]; 2603 2604 if (fd == -1) 2605 return; 2606 if (p == -1 || (u_int)p >= npfd) 2607 fatal_f("channel %d: bad pfd %d (max %u)", c->self, p, npfd); 2608 dump_channel_poll(__func__, what, c, p, pfd); 2609 if (pfd->fd != fd) { 2610 fatal("channel %d: inconsistent %s fd=%d pollfd[%u].fd %d " 2611 "r%d w%d e%d s%d", c->self, what, fd, p, pfd->fd, 2612 c->rfd, c->wfd, c->efd, c->sock); 2613 } 2614 if ((pfd->revents & POLLNVAL) != 0) { 2615 fatal("channel %d: invalid %s pollfd[%u].fd %d r%d w%d e%d s%d", 2616 c->self, what, p, pfd->fd, c->rfd, c->wfd, c->efd, c->sock); 2617 } 2618 if ((pfd->revents & (revents_mask|POLLHUP|POLLERR)) != 0) 2619 c->io_ready |= ready & c->io_want; 2620 } 2621 2622 /* 2623 * After poll, perform any appropriate operations for channels which have 2624 * events pending. 2625 */ 2626 void 2627 channel_after_poll(struct ssh *ssh, struct pollfd *pfd, u_int npfd) 2628 { 2629 struct ssh_channels *sc = ssh->chanctxt; 2630 u_int i; 2631 int p; 2632 Channel *c; 2633 2634 #ifdef DEBUG_CHANNEL_POLL 2635 for (p = 0; p < (int)npfd; p++) { 2636 if (pfd[p].revents == 0) 2637 continue; 2638 debug_f("pfd[%u].fd %d rev 0x%04x", 2639 p, pfd[p].fd, pfd[p].revents); 2640 } 2641 #endif 2642 2643 /* Convert pollfd into c->io_ready */ 2644 for (i = 0; i < sc->channels_alloc; i++) { 2645 c = sc->channels[i]; 2646 if (c == NULL) 2647 continue; 2648 /* if rfd is shared with efd/sock then wfd should be too */ 2649 if (c->rfd != -1 && c->wfd != -1 && c->rfd != c->wfd && 2650 (c->rfd == c->efd || c->rfd == c->sock)) { 2651 /* Shouldn't happen */ 2652 fatal_f("channel %d: unexpected fds r%d w%d e%d s%d", 2653 c->self, c->rfd, c->wfd, c->efd, c->sock); 2654 } 2655 c->io_ready = 0; 2656 /* rfd, potentially shared with wfd, efd and sock */ 2657 if (c->rfd != -1 && (p = c->pfds[0]) != -1) { 2658 fd_ready(c, p, pfd, npfd, c->rfd, 2659 "rfd", POLLIN, SSH_CHAN_IO_RFD); 2660 if (c->rfd == c->wfd) { 2661 fd_ready(c, p, pfd, npfd, c->wfd, 2662 "wfd/r", POLLOUT, SSH_CHAN_IO_WFD); 2663 } 2664 if (c->rfd == c->efd) { 2665 fd_ready(c, p, pfd, npfd, c->efd, 2666 "efdr/r", POLLIN, SSH_CHAN_IO_EFD_R); 2667 fd_ready(c, p, pfd, npfd, c->efd, 2668 "efdw/r", POLLOUT, SSH_CHAN_IO_EFD_W); 2669 } 2670 if (c->rfd == c->sock) { 2671 fd_ready(c, p, pfd, npfd, c->sock, 2672 "sockr/r", POLLIN, SSH_CHAN_IO_SOCK_R); 2673 fd_ready(c, p, pfd, npfd, c->sock, 2674 "sockw/r", POLLOUT, SSH_CHAN_IO_SOCK_W); 2675 } 2676 dump_channel_poll(__func__, "rfd", c, p, pfd); 2677 } 2678 /* wfd */ 2679 if (c->wfd != -1 && c->wfd != c->rfd && 2680 (p = c->pfds[1]) != -1) { 2681 fd_ready(c, p, pfd, npfd, c->wfd, 2682 "wfd", POLLOUT, SSH_CHAN_IO_WFD); 2683 dump_channel_poll(__func__, "wfd", c, p, pfd); 2684 } 2685 /* efd */ 2686 if (c->efd != -1 && c->efd != c->rfd && 2687 (p = c->pfds[2]) != -1) { 2688 fd_ready(c, p, pfd, npfd, c->efd, 2689 "efdr", POLLIN, SSH_CHAN_IO_EFD_R); 2690 fd_ready(c, p, pfd, npfd, c->efd, 2691 "efdw", POLLOUT, SSH_CHAN_IO_EFD_W); 2692 dump_channel_poll(__func__, "efd", c, p, pfd); 2693 } 2694 /* sock */ 2695 if (c->sock != -1 && c->sock != c->rfd && 2696 (p = c->pfds[3]) != -1) { 2697 fd_ready(c, p, pfd, npfd, c->sock, 2698 "sockr", POLLIN, SSH_CHAN_IO_SOCK_R); 2699 fd_ready(c, p, pfd, npfd, c->sock, 2700 "sockw", POLLOUT, SSH_CHAN_IO_SOCK_W); 2701 dump_channel_poll(__func__, "sock", c, p, pfd); 2702 } 2703 } 2704 channel_handler(ssh, CHAN_POST, NULL); 2705 } 2706 2707 /* 2708 * Enqueue data for channels with open or draining c->input. 2709 */ 2710 static void 2711 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2712 { 2713 size_t len, plen; 2714 const u_char *pkt; 2715 int r; 2716 2717 if ((len = sshbuf_len(c->input)) == 0) { 2718 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2719 /* 2720 * input-buffer is empty and read-socket shutdown: 2721 * tell peer, that we will not send more data: 2722 * send IEOF. 2723 * hack for extended data: delay EOF if EFD still 2724 * in use. 2725 */ 2726 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2727 debug2("channel %d: " 2728 "ibuf_empty delayed efd %d/(%zu)", 2729 c->self, c->efd, sshbuf_len(c->extended)); 2730 else 2731 chan_ibuf_empty(ssh, c); 2732 } 2733 return; 2734 } 2735 2736 if (!c->have_remote_id) 2737 fatal_f("channel %d: no remote id", c->self); 2738 2739 if (c->datagram) { 2740 /* Check datagram will fit; drop if not */ 2741 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2742 fatal_fr(r, "channel %i: get datagram", c->self); 2743 /* 2744 * XXX this does tail-drop on the datagram queue which is 2745 * usually suboptimal compared to head-drop. Better to have 2746 * backpressure at read time? (i.e. read + discard) 2747 */ 2748 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2749 debug("channel %d: datagram too big", c->self); 2750 return; 2751 } 2752 /* Enqueue it */ 2753 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2754 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2755 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2756 (r = sshpkt_send(ssh)) != 0) 2757 fatal_fr(r, "channel %i: send datagram", c->self); 2758 c->remote_window -= plen; 2759 return; 2760 } 2761 2762 /* Enqueue packet for buffered data. */ 2763 if (len > c->remote_window) 2764 len = c->remote_window; 2765 if (len > c->remote_maxpacket) 2766 len = c->remote_maxpacket; 2767 if (len == 0) 2768 return; 2769 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2770 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2771 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2772 (r = sshpkt_send(ssh)) != 0) 2773 fatal_fr(r, "channel %i: send data", c->self); 2774 if ((r = sshbuf_consume(c->input, len)) != 0) 2775 fatal_fr(r, "channel %i: consume", c->self); 2776 c->remote_window -= len; 2777 } 2778 2779 /* 2780 * Enqueue data for channels with open c->extended in read mode. 2781 */ 2782 static void 2783 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2784 { 2785 size_t len; 2786 int r; 2787 2788 if ((len = sshbuf_len(c->extended)) == 0) 2789 return; 2790 2791 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2792 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2793 if (len > c->remote_window) 2794 len = c->remote_window; 2795 if (len > c->remote_maxpacket) 2796 len = c->remote_maxpacket; 2797 if (len == 0) 2798 return; 2799 if (!c->have_remote_id) 2800 fatal_f("channel %d: no remote id", c->self); 2801 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2802 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2803 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2804 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2805 (r = sshpkt_send(ssh)) != 0) 2806 fatal_fr(r, "channel %i: data", c->self); 2807 if ((r = sshbuf_consume(c->extended, len)) != 0) 2808 fatal_fr(r, "channel %i: consume", c->self); 2809 c->remote_window -= len; 2810 debug2("channel %d: sent ext data %zu", c->self, len); 2811 } 2812 2813 /* If there is data to send to the connection, enqueue some of it now. */ 2814 void 2815 channel_output_poll(struct ssh *ssh) 2816 { 2817 struct ssh_channels *sc = ssh->chanctxt; 2818 Channel *c; 2819 u_int i; 2820 2821 for (i = 0; i < sc->channels_alloc; i++) { 2822 c = sc->channels[i]; 2823 if (c == NULL) 2824 continue; 2825 2826 /* 2827 * We are only interested in channels that can have buffered 2828 * incoming data. 2829 */ 2830 if (c->type != SSH_CHANNEL_OPEN) 2831 continue; 2832 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2833 /* XXX is this true? */ 2834 debug3("channel %d: will not send data after close", 2835 c->self); 2836 continue; 2837 } 2838 2839 /* Get the amount of buffered data for this channel. */ 2840 if (c->istate == CHAN_INPUT_OPEN || 2841 c->istate == CHAN_INPUT_WAIT_DRAIN) 2842 channel_output_poll_input_open(ssh, c); 2843 /* Send extended data, i.e. stderr */ 2844 if (!(c->flags & CHAN_EOF_SENT) && 2845 c->extended_usage == CHAN_EXTENDED_READ) 2846 channel_output_poll_extended_read(ssh, c); 2847 } 2848 } 2849 2850 /* -- mux proxy support */ 2851 2852 /* 2853 * When multiplexing channel messages for mux clients we have to deal 2854 * with downstream messages from the mux client and upstream messages 2855 * from the ssh server: 2856 * 1) Handling downstream messages is straightforward and happens 2857 * in channel_proxy_downstream(): 2858 * - We forward all messages (mostly) unmodified to the server. 2859 * - However, in order to route messages from upstream to the correct 2860 * downstream client, we have to replace the channel IDs used by the 2861 * mux clients with a unique channel ID because the mux clients might 2862 * use conflicting channel IDs. 2863 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 2864 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 2865 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 2866 * with the newly allocated channel ID. 2867 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 2868 * channels and processed by channel_proxy_upstream(). The local channel ID 2869 * is then translated back to the original mux client ID. 2870 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 2871 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 2872 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 2873 * downstream mux client are removed. 2874 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 2875 * requires more work, because they are not addressed to a specific 2876 * channel. E.g. client_request_forwarded_tcpip() needs to figure 2877 * out whether the request is addressed to the local client or a 2878 * specific downstream client based on the listen-address/port. 2879 * 6) Agent and X11-Forwarding have a similar problem and are currently 2880 * not supported as the matching session/channel cannot be identified 2881 * easily. 2882 */ 2883 2884 /* 2885 * receive packets from downstream mux clients: 2886 * channel callback fired on read from mux client, creates 2887 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 2888 * on channel creation. 2889 */ 2890 int 2891 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 2892 { 2893 Channel *c = NULL; 2894 struct sshbuf *original = NULL, *modified = NULL; 2895 const u_char *cp; 2896 char *ctype = NULL, *listen_host = NULL; 2897 u_char type; 2898 size_t have; 2899 int ret = -1, r; 2900 u_int id, remote_id, listen_port; 2901 2902 /* sshbuf_dump(downstream->input, stderr); */ 2903 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 2904 != 0) { 2905 error_fr(r, "parse"); 2906 return -1; 2907 } 2908 if (have < 2) { 2909 error_f("short message"); 2910 return -1; 2911 } 2912 type = cp[1]; 2913 /* skip padlen + type */ 2914 cp += 2; 2915 have -= 2; 2916 if (ssh_packet_log_type(type)) 2917 debug3_f("channel %u: down->up: type %u", 2918 downstream->self, type); 2919 2920 switch (type) { 2921 case SSH2_MSG_CHANNEL_OPEN: 2922 if ((original = sshbuf_from(cp, have)) == NULL || 2923 (modified = sshbuf_new()) == NULL) { 2924 error_f("alloc"); 2925 goto out; 2926 } 2927 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 2928 (r = sshbuf_get_u32(original, &id)) != 0) { 2929 error_fr(r, "parse"); 2930 goto out; 2931 } 2932 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2933 -1, -1, -1, 0, 0, 0, ctype, 1); 2934 c->mux_ctx = downstream; /* point to mux client */ 2935 c->mux_downstream_id = id; /* original downstream id */ 2936 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 2937 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2938 (r = sshbuf_putb(modified, original)) != 0) { 2939 error_fr(r, "compose"); 2940 channel_free(ssh, c); 2941 goto out; 2942 } 2943 break; 2944 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2945 /* 2946 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 2947 * need to parse 'remote_id' instead of 'ctype'. 2948 */ 2949 if ((original = sshbuf_from(cp, have)) == NULL || 2950 (modified = sshbuf_new()) == NULL) { 2951 error_f("alloc"); 2952 goto out; 2953 } 2954 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 2955 (r = sshbuf_get_u32(original, &id)) != 0) { 2956 error_fr(r, "parse"); 2957 goto out; 2958 } 2959 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2960 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 2961 c->mux_ctx = downstream; /* point to mux client */ 2962 c->mux_downstream_id = id; 2963 c->remote_id = remote_id; 2964 c->have_remote_id = 1; 2965 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 2966 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2967 (r = sshbuf_putb(modified, original)) != 0) { 2968 error_fr(r, "compose"); 2969 channel_free(ssh, c); 2970 goto out; 2971 } 2972 break; 2973 case SSH2_MSG_GLOBAL_REQUEST: 2974 if ((original = sshbuf_from(cp, have)) == NULL) { 2975 error_f("alloc"); 2976 goto out; 2977 } 2978 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 2979 error_fr(r, "parse"); 2980 goto out; 2981 } 2982 if (strcmp(ctype, "tcpip-forward") != 0) { 2983 error_f("unsupported request %s", ctype); 2984 goto out; 2985 } 2986 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 2987 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 2988 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 2989 error_fr(r, "parse"); 2990 goto out; 2991 } 2992 if (listen_port > 65535) { 2993 error_f("tcpip-forward for %s: bad port %u", 2994 listen_host, listen_port); 2995 goto out; 2996 } 2997 /* Record that connection to this host/port is permitted. */ 2998 permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, 2999 listen_host, NULL, (int)listen_port, downstream); 3000 listen_host = NULL; 3001 break; 3002 case SSH2_MSG_CHANNEL_CLOSE: 3003 if (have < 4) 3004 break; 3005 remote_id = PEEK_U32(cp); 3006 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 3007 if (c->flags & CHAN_CLOSE_RCVD) 3008 channel_free(ssh, c); 3009 else 3010 c->flags |= CHAN_CLOSE_SENT; 3011 } 3012 break; 3013 } 3014 if (modified) { 3015 if ((r = sshpkt_start(ssh, type)) != 0 || 3016 (r = sshpkt_putb(ssh, modified)) != 0 || 3017 (r = sshpkt_send(ssh)) != 0) { 3018 error_fr(r, "send"); 3019 goto out; 3020 } 3021 } else { 3022 if ((r = sshpkt_start(ssh, type)) != 0 || 3023 (r = sshpkt_put(ssh, cp, have)) != 0 || 3024 (r = sshpkt_send(ssh)) != 0) { 3025 error_fr(r, "send"); 3026 goto out; 3027 } 3028 } 3029 ret = 0; 3030 out: 3031 free(ctype); 3032 free(listen_host); 3033 sshbuf_free(original); 3034 sshbuf_free(modified); 3035 return ret; 3036 } 3037 3038 /* 3039 * receive packets from upstream server and de-multiplex packets 3040 * to correct downstream: 3041 * implemented as a helper for channel input handlers, 3042 * replaces local (proxy) channel ID with downstream channel ID. 3043 */ 3044 int 3045 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 3046 { 3047 struct sshbuf *b = NULL; 3048 Channel *downstream; 3049 const u_char *cp = NULL; 3050 size_t len; 3051 int r; 3052 3053 /* 3054 * When receiving packets from the peer we need to check whether we 3055 * need to forward the packets to the mux client. In this case we 3056 * restore the original channel id and keep track of CLOSE messages, 3057 * so we can cleanup the channel. 3058 */ 3059 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 3060 return 0; 3061 if ((downstream = c->mux_ctx) == NULL) 3062 return 0; 3063 switch (type) { 3064 case SSH2_MSG_CHANNEL_CLOSE: 3065 case SSH2_MSG_CHANNEL_DATA: 3066 case SSH2_MSG_CHANNEL_EOF: 3067 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 3068 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3069 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 3070 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 3071 case SSH2_MSG_CHANNEL_SUCCESS: 3072 case SSH2_MSG_CHANNEL_FAILURE: 3073 case SSH2_MSG_CHANNEL_REQUEST: 3074 break; 3075 default: 3076 debug2_f("channel %u: unsupported type %u", c->self, type); 3077 return 0; 3078 } 3079 if ((b = sshbuf_new()) == NULL) { 3080 error_f("alloc reply"); 3081 goto out; 3082 } 3083 /* get remaining payload (after id) */ 3084 cp = sshpkt_ptr(ssh, &len); 3085 if (cp == NULL) { 3086 error_f("no packet"); 3087 goto out; 3088 } 3089 /* translate id and send to muxclient */ 3090 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 3091 (r = sshbuf_put_u8(b, type)) != 0 || 3092 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 3093 (r = sshbuf_put(b, cp, len)) != 0 || 3094 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 3095 error_fr(r, "compose muxclient"); 3096 goto out; 3097 } 3098 /* sshbuf_dump(b, stderr); */ 3099 if (ssh_packet_log_type(type)) 3100 debug3_f("channel %u: up->down: type %u", c->self, type); 3101 out: 3102 /* update state */ 3103 switch (type) { 3104 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 3105 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 3106 if (cp && len > 4) { 3107 c->remote_id = PEEK_U32(cp); 3108 c->have_remote_id = 1; 3109 } 3110 break; 3111 case SSH2_MSG_CHANNEL_CLOSE: 3112 if (c->flags & CHAN_CLOSE_SENT) 3113 channel_free(ssh, c); 3114 else 3115 c->flags |= CHAN_CLOSE_RCVD; 3116 break; 3117 } 3118 sshbuf_free(b); 3119 return 1; 3120 } 3121 3122 /* -- protocol input */ 3123 3124 /* Parse a channel ID from the current packet */ 3125 static int 3126 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 3127 { 3128 u_int32_t id; 3129 int r; 3130 3131 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 3132 error_r(r, "%s: parse id", where); 3133 ssh_packet_disconnect(ssh, "Invalid %s message", what); 3134 } 3135 if (id > INT_MAX) { 3136 error_r(r, "%s: bad channel id %u", where, id); 3137 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 3138 } 3139 return (int)id; 3140 } 3141 3142 /* Lookup a channel from an ID in the current packet */ 3143 static Channel * 3144 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 3145 { 3146 int id = channel_parse_id(ssh, where, what); 3147 Channel *c; 3148 3149 if ((c = channel_lookup(ssh, id)) == NULL) { 3150 ssh_packet_disconnect(ssh, 3151 "%s packet referred to nonexistent channel %d", what, id); 3152 } 3153 return c; 3154 } 3155 3156 int 3157 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 3158 { 3159 const u_char *data; 3160 size_t data_len, win_len; 3161 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 3162 int r; 3163 3164 if (channel_proxy_upstream(c, type, seq, ssh)) 3165 return 0; 3166 3167 /* Ignore any data for non-open channels (might happen on close) */ 3168 if (c->type != SSH_CHANNEL_OPEN && 3169 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 3170 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 3171 c->type != SSH_CHANNEL_X11_OPEN) 3172 return 0; 3173 3174 /* Get the data. */ 3175 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3176 (r = sshpkt_get_end(ssh)) != 0) 3177 fatal_fr(r, "channel %i: get data", c->self); 3178 3179 win_len = data_len; 3180 if (c->datagram) 3181 win_len += 4; /* string length header */ 3182 3183 /* 3184 * The sending side reduces its window as it sends data, so we 3185 * must 'fake' consumption of the data in order to ensure that window 3186 * updates are sent back. Otherwise the connection might deadlock. 3187 */ 3188 if (c->ostate != CHAN_OUTPUT_OPEN) { 3189 c->local_window -= win_len; 3190 c->local_consumed += win_len; 3191 return 0; 3192 } 3193 3194 if (win_len > c->local_maxpacket) { 3195 logit("channel %d: rcvd big packet %zu, maxpack %u", 3196 c->self, win_len, c->local_maxpacket); 3197 return 0; 3198 } 3199 if (win_len > c->local_window) { 3200 logit("channel %d: rcvd too much data %zu, win %u", 3201 c->self, win_len, c->local_window); 3202 return 0; 3203 } 3204 c->local_window -= win_len; 3205 3206 if (c->datagram) { 3207 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 3208 fatal_fr(r, "channel %i: append datagram", c->self); 3209 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 3210 fatal_fr(r, "channel %i: append data", c->self); 3211 3212 return 0; 3213 } 3214 3215 int 3216 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 3217 { 3218 const u_char *data; 3219 size_t data_len; 3220 u_int32_t tcode; 3221 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 3222 int r; 3223 3224 if (channel_proxy_upstream(c, type, seq, ssh)) 3225 return 0; 3226 if (c->type != SSH_CHANNEL_OPEN) { 3227 logit("channel %d: ext data for non open", c->self); 3228 return 0; 3229 } 3230 if (c->flags & CHAN_EOF_RCVD) { 3231 if (ssh->compat & SSH_BUG_EXTEOF) 3232 debug("channel %d: accepting ext data after eof", 3233 c->self); 3234 else 3235 ssh_packet_disconnect(ssh, "Received extended_data " 3236 "after EOF on channel %d.", c->self); 3237 } 3238 3239 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 3240 error_fr(r, "parse tcode"); 3241 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3242 } 3243 if (c->efd == -1 || 3244 c->extended_usage != CHAN_EXTENDED_WRITE || 3245 tcode != SSH2_EXTENDED_DATA_STDERR) { 3246 logit("channel %d: bad ext data", c->self); 3247 return 0; 3248 } 3249 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || 3250 (r = sshpkt_get_end(ssh)) != 0) { 3251 error_fr(r, "parse data"); 3252 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 3253 } 3254 3255 if (data_len > c->local_window) { 3256 logit("channel %d: rcvd too much extended_data %zu, win %u", 3257 c->self, data_len, c->local_window); 3258 return 0; 3259 } 3260 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 3261 /* XXX sshpkt_getb? */ 3262 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 3263 error_fr(r, "append"); 3264 c->local_window -= data_len; 3265 return 0; 3266 } 3267 3268 int 3269 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 3270 { 3271 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 3272 int r; 3273 3274 if ((r = sshpkt_get_end(ssh)) != 0) { 3275 error_fr(r, "parse data"); 3276 ssh_packet_disconnect(ssh, "Invalid ieof message"); 3277 } 3278 3279 if (channel_proxy_upstream(c, type, seq, ssh)) 3280 return 0; 3281 chan_rcvd_ieof(ssh, c); 3282 3283 /* XXX force input close */ 3284 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 3285 debug("channel %d: FORCE input drain", c->self); 3286 c->istate = CHAN_INPUT_WAIT_DRAIN; 3287 if (sshbuf_len(c->input) == 0) 3288 chan_ibuf_empty(ssh, c); 3289 } 3290 return 0; 3291 } 3292 3293 int 3294 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 3295 { 3296 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3297 int r; 3298 3299 if (channel_proxy_upstream(c, type, seq, ssh)) 3300 return 0; 3301 if ((r = sshpkt_get_end(ssh)) != 0) { 3302 error_fr(r, "parse data"); 3303 ssh_packet_disconnect(ssh, "Invalid oclose message"); 3304 } 3305 chan_rcvd_oclose(ssh, c); 3306 return 0; 3307 } 3308 3309 int 3310 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3311 { 3312 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3313 u_int32_t remote_window, remote_maxpacket; 3314 int r; 3315 3316 if (channel_proxy_upstream(c, type, seq, ssh)) 3317 return 0; 3318 if (c->type != SSH_CHANNEL_OPENING) 3319 ssh_packet_disconnect(ssh, "Received open confirmation for " 3320 "non-opening channel %d.", c->self); 3321 /* 3322 * Record the remote channel number and mark that the channel 3323 * is now open. 3324 */ 3325 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3326 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3327 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || 3328 (r = sshpkt_get_end(ssh)) != 0) { 3329 error_fr(r, "window/maxpacket"); 3330 ssh_packet_disconnect(ssh, "Invalid open confirmation message"); 3331 } 3332 3333 c->have_remote_id = 1; 3334 c->remote_window = remote_window; 3335 c->remote_maxpacket = remote_maxpacket; 3336 c->type = SSH_CHANNEL_OPEN; 3337 if (c->open_confirm) { 3338 debug2_f("channel %d: callback start", c->self); 3339 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3340 debug2_f("channel %d: callback done", c->self); 3341 } 3342 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3343 c->remote_window, c->remote_maxpacket); 3344 return 0; 3345 } 3346 3347 static char * 3348 reason2txt(int reason) 3349 { 3350 switch (reason) { 3351 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3352 return "administratively prohibited"; 3353 case SSH2_OPEN_CONNECT_FAILED: 3354 return "connect failed"; 3355 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3356 return "unknown channel type"; 3357 case SSH2_OPEN_RESOURCE_SHORTAGE: 3358 return "resource shortage"; 3359 } 3360 return "unknown reason"; 3361 } 3362 3363 int 3364 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3365 { 3366 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3367 u_int32_t reason; 3368 char *msg = NULL; 3369 int r; 3370 3371 if (channel_proxy_upstream(c, type, seq, ssh)) 3372 return 0; 3373 if (c->type != SSH_CHANNEL_OPENING) 3374 ssh_packet_disconnect(ssh, "Received open failure for " 3375 "non-opening channel %d.", c->self); 3376 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3377 error_fr(r, "parse reason"); 3378 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3379 } 3380 /* skip language */ 3381 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3382 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || 3383 (r = sshpkt_get_end(ssh)) != 0) { 3384 error_fr(r, "parse msg/lang"); 3385 ssh_packet_disconnect(ssh, "Invalid open failure message"); 3386 } 3387 logit("channel %d: open failed: %s%s%s", c->self, 3388 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3389 free(msg); 3390 if (c->open_confirm) { 3391 debug2_f("channel %d: callback start", c->self); 3392 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3393 debug2_f("channel %d: callback done", c->self); 3394 } 3395 /* Schedule the channel for cleanup/deletion. */ 3396 chan_mark_dead(ssh, c); 3397 return 0; 3398 } 3399 3400 int 3401 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3402 { 3403 int id = channel_parse_id(ssh, __func__, "window adjust"); 3404 Channel *c; 3405 u_int32_t adjust; 3406 u_int new_rwin; 3407 int r; 3408 3409 if ((c = channel_lookup(ssh, id)) == NULL) { 3410 logit("Received window adjust for non-open channel %d.", id); 3411 return 0; 3412 } 3413 3414 if (channel_proxy_upstream(c, type, seq, ssh)) 3415 return 0; 3416 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || 3417 (r = sshpkt_get_end(ssh)) != 0) { 3418 error_fr(r, "parse adjust"); 3419 ssh_packet_disconnect(ssh, "Invalid window adjust message"); 3420 } 3421 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3422 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3423 fatal("channel %d: adjust %u overflows remote window %u", 3424 c->self, adjust, c->remote_window); 3425 } 3426 c->remote_window = new_rwin; 3427 return 0; 3428 } 3429 3430 int 3431 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3432 { 3433 int id = channel_parse_id(ssh, __func__, "status confirm"); 3434 Channel *c; 3435 struct channel_confirm *cc; 3436 3437 /* Reset keepalive timeout */ 3438 ssh_packet_set_alive_timeouts(ssh, 0); 3439 3440 debug2_f("type %d id %d", type, id); 3441 3442 if ((c = channel_lookup(ssh, id)) == NULL) { 3443 logit_f("%d: unknown", id); 3444 return 0; 3445 } 3446 if (channel_proxy_upstream(c, type, seq, ssh)) 3447 return 0; 3448 if (sshpkt_get_end(ssh) != 0) 3449 ssh_packet_disconnect(ssh, "Invalid status confirm message"); 3450 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3451 return 0; 3452 cc->cb(ssh, type, c, cc->ctx); 3453 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3454 freezero(cc, sizeof(*cc)); 3455 return 0; 3456 } 3457 3458 /* -- tcp forwarding */ 3459 3460 void 3461 channel_set_af(struct ssh *ssh, int af) 3462 { 3463 ssh->chanctxt->IPv4or6 = af; 3464 } 3465 3466 3467 /* 3468 * Determine whether or not a port forward listens to loopback, the 3469 * specified address or wildcard. On the client, a specified bind 3470 * address will always override gateway_ports. On the server, a 3471 * gateway_ports of 1 (``yes'') will override the client's specification 3472 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3473 * will bind to whatever address the client asked for. 3474 * 3475 * Special-case listen_addrs are: 3476 * 3477 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3478 * "" (empty string), "*" -> wildcard v4/v6 3479 * "localhost" -> loopback v4/v6 3480 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3481 */ 3482 static const char * 3483 channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, 3484 int is_client, struct ForwardOptions *fwd_opts) 3485 { 3486 const char *addr = NULL; 3487 int wildcard = 0; 3488 3489 if (listen_addr == NULL) { 3490 /* No address specified: default to gateway_ports setting */ 3491 if (fwd_opts->gateway_ports) 3492 wildcard = 1; 3493 } else if (fwd_opts->gateway_ports || is_client) { 3494 if (((ssh->compat & SSH_OLD_FORWARD_ADDR) && 3495 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3496 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3497 (!is_client && fwd_opts->gateway_ports == 1)) { 3498 wildcard = 1; 3499 /* 3500 * Notify client if they requested a specific listen 3501 * address and it was overridden. 3502 */ 3503 if (*listen_addr != '\0' && 3504 strcmp(listen_addr, "0.0.0.0") != 0 && 3505 strcmp(listen_addr, "*") != 0) { 3506 ssh_packet_send_debug(ssh, 3507 "Forwarding listen address " 3508 "\"%s\" overridden by server " 3509 "GatewayPorts", listen_addr); 3510 } 3511 } else if (strcmp(listen_addr, "localhost") != 0 || 3512 strcmp(listen_addr, "127.0.0.1") == 0 || 3513 strcmp(listen_addr, "::1") == 0) { 3514 /* 3515 * Accept explicit localhost address when 3516 * GatewayPorts=yes. The "localhost" hostname is 3517 * deliberately skipped here so it will listen on all 3518 * available local address families. 3519 */ 3520 addr = listen_addr; 3521 } 3522 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3523 strcmp(listen_addr, "::1") == 0) { 3524 /* 3525 * If a specific IPv4/IPv6 localhost address has been 3526 * requested then accept it even if gateway_ports is in 3527 * effect. This allows the client to prefer IPv4 or IPv6. 3528 */ 3529 addr = listen_addr; 3530 } 3531 if (wildcardp != NULL) 3532 *wildcardp = wildcard; 3533 return addr; 3534 } 3535 3536 static int 3537 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3538 struct Forward *fwd, int *allocated_listen_port, 3539 struct ForwardOptions *fwd_opts) 3540 { 3541 Channel *c; 3542 int sock, r, success = 0, wildcard = 0, is_client; 3543 struct addrinfo hints, *ai, *aitop; 3544 const char *host, *addr; 3545 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3546 in_port_t *lport_p; 3547 3548 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3549 3550 if (is_client && fwd->connect_path != NULL) { 3551 host = fwd->connect_path; 3552 } else { 3553 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3554 fwd->listen_host : fwd->connect_host; 3555 if (host == NULL) { 3556 error("No forward host name."); 3557 return 0; 3558 } 3559 if (strlen(host) >= NI_MAXHOST) { 3560 error("Forward host name too long."); 3561 return 0; 3562 } 3563 } 3564 3565 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3566 addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, 3567 is_client, fwd_opts); 3568 debug3_f("type %d wildcard %d addr %s", type, wildcard, 3569 (addr == NULL) ? "NULL" : addr); 3570 3571 /* 3572 * getaddrinfo returns a loopback address if the hostname is 3573 * set to NULL and hints.ai_flags is not AI_PASSIVE 3574 */ 3575 memset(&hints, 0, sizeof(hints)); 3576 hints.ai_family = ssh->chanctxt->IPv4or6; 3577 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3578 hints.ai_socktype = SOCK_STREAM; 3579 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3580 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3581 if (addr == NULL) { 3582 /* This really shouldn't happen */ 3583 ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", 3584 ssh_gai_strerror(r)); 3585 } else { 3586 error_f("getaddrinfo(%.64s): %s", addr, 3587 ssh_gai_strerror(r)); 3588 } 3589 return 0; 3590 } 3591 if (allocated_listen_port != NULL) 3592 *allocated_listen_port = 0; 3593 for (ai = aitop; ai; ai = ai->ai_next) { 3594 switch (ai->ai_family) { 3595 case AF_INET: 3596 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3597 sin_port; 3598 break; 3599 case AF_INET6: 3600 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3601 sin6_port; 3602 break; 3603 default: 3604 continue; 3605 } 3606 /* 3607 * If allocating a port for -R forwards, then use the 3608 * same port for all address families. 3609 */ 3610 if (type == SSH_CHANNEL_RPORT_LISTENER && 3611 fwd->listen_port == 0 && allocated_listen_port != NULL && 3612 *allocated_listen_port > 0) 3613 *lport_p = htons(*allocated_listen_port); 3614 3615 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3616 strport, sizeof(strport), 3617 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3618 error_f("getnameinfo failed"); 3619 continue; 3620 } 3621 /* Create a port to listen for the host. */ 3622 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3623 if (sock == -1) { 3624 /* this is no error since kernel may not support ipv6 */ 3625 verbose("socket [%s]:%s: %.100s", ntop, strport, 3626 strerror(errno)); 3627 continue; 3628 } 3629 3630 set_reuseaddr(sock); 3631 3632 debug("Local forwarding listening on %s port %s.", 3633 ntop, strport); 3634 3635 /* Bind the socket to the address. */ 3636 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 3637 /* 3638 * address can be in if use ipv6 address is 3639 * already bound 3640 */ 3641 verbose("bind [%s]:%s: %.100s", 3642 ntop, strport, strerror(errno)); 3643 close(sock); 3644 continue; 3645 } 3646 /* Start listening for connections on the socket. */ 3647 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 3648 error("listen [%s]:%s: %.100s", ntop, strport, 3649 strerror(errno)); 3650 close(sock); 3651 continue; 3652 } 3653 3654 /* 3655 * fwd->listen_port == 0 requests a dynamically allocated port - 3656 * record what we got. 3657 */ 3658 if (type == SSH_CHANNEL_RPORT_LISTENER && 3659 fwd->listen_port == 0 && 3660 allocated_listen_port != NULL && 3661 *allocated_listen_port == 0) { 3662 *allocated_listen_port = get_local_port(sock); 3663 debug("Allocated listen port %d", 3664 *allocated_listen_port); 3665 } 3666 3667 /* Allocate a channel number for the socket. */ 3668 c = channel_new(ssh, "port listener", type, sock, sock, -1, 3669 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3670 0, "port listener", 1); 3671 c->path = xstrdup(host); 3672 c->host_port = fwd->connect_port; 3673 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3674 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3675 !(ssh->compat & SSH_BUG_DYNAMIC_RPORT)) 3676 c->listening_port = *allocated_listen_port; 3677 else 3678 c->listening_port = fwd->listen_port; 3679 success = 1; 3680 } 3681 if (success == 0) 3682 error_f("cannot listen to port: %d", fwd->listen_port); 3683 freeaddrinfo(aitop); 3684 return success; 3685 } 3686 3687 static int 3688 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3689 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3690 { 3691 struct sockaddr_un sunaddr; 3692 const char *path; 3693 Channel *c; 3694 int port, sock; 3695 mode_t omask; 3696 3697 switch (type) { 3698 case SSH_CHANNEL_UNIX_LISTENER: 3699 if (fwd->connect_path != NULL) { 3700 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3701 error("Local connecting path too long: %s", 3702 fwd->connect_path); 3703 return 0; 3704 } 3705 path = fwd->connect_path; 3706 port = PORT_STREAMLOCAL; 3707 } else { 3708 if (fwd->connect_host == NULL) { 3709 error("No forward host name."); 3710 return 0; 3711 } 3712 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3713 error("Forward host name too long."); 3714 return 0; 3715 } 3716 path = fwd->connect_host; 3717 port = fwd->connect_port; 3718 } 3719 break; 3720 case SSH_CHANNEL_RUNIX_LISTENER: 3721 path = fwd->listen_path; 3722 port = PORT_STREAMLOCAL; 3723 break; 3724 default: 3725 error_f("unexpected channel type %d", type); 3726 return 0; 3727 } 3728 3729 if (fwd->listen_path == NULL) { 3730 error("No forward path name."); 3731 return 0; 3732 } 3733 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3734 error("Local listening path too long: %s", fwd->listen_path); 3735 return 0; 3736 } 3737 3738 debug3_f("type %d path %s", type, fwd->listen_path); 3739 3740 /* Start a Unix domain listener. */ 3741 omask = umask(fwd_opts->streamlocal_bind_mask); 3742 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3743 fwd_opts->streamlocal_bind_unlink); 3744 umask(omask); 3745 if (sock < 0) 3746 return 0; 3747 3748 debug("Local forwarding listening on path %s.", fwd->listen_path); 3749 3750 /* Allocate a channel number for the socket. */ 3751 c = channel_new(ssh, "unix listener", type, sock, sock, -1, 3752 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3753 0, "unix listener", 1); 3754 c->path = xstrdup(path); 3755 c->host_port = port; 3756 c->listening_port = PORT_STREAMLOCAL; 3757 c->listening_addr = xstrdup(fwd->listen_path); 3758 return 1; 3759 } 3760 3761 static int 3762 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3763 const char *host, u_short port) 3764 { 3765 u_int i; 3766 int found = 0; 3767 3768 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3769 Channel *c = ssh->chanctxt->channels[i]; 3770 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3771 continue; 3772 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3773 debug2_f("close channel %d", i); 3774 channel_free(ssh, c); 3775 found = 1; 3776 } 3777 } 3778 3779 return found; 3780 } 3781 3782 static int 3783 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3784 { 3785 u_int i; 3786 int found = 0; 3787 3788 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3789 Channel *c = ssh->chanctxt->channels[i]; 3790 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3791 continue; 3792 if (c->path == NULL) 3793 continue; 3794 if (strcmp(c->path, path) == 0) { 3795 debug2_f("close channel %d", i); 3796 channel_free(ssh, c); 3797 found = 1; 3798 } 3799 } 3800 3801 return found; 3802 } 3803 3804 int 3805 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3806 { 3807 if (fwd->listen_path != NULL) { 3808 return channel_cancel_rport_listener_streamlocal(ssh, 3809 fwd->listen_path); 3810 } else { 3811 return channel_cancel_rport_listener_tcpip(ssh, 3812 fwd->listen_host, fwd->listen_port); 3813 } 3814 } 3815 3816 static int 3817 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 3818 const char *lhost, u_short lport, int cport, 3819 struct ForwardOptions *fwd_opts) 3820 { 3821 u_int i; 3822 int found = 0; 3823 const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); 3824 3825 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3826 Channel *c = ssh->chanctxt->channels[i]; 3827 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 3828 continue; 3829 if (c->listening_port != lport) 3830 continue; 3831 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 3832 /* skip dynamic forwardings */ 3833 if (c->host_port == 0) 3834 continue; 3835 } else { 3836 if (c->host_port != cport) 3837 continue; 3838 } 3839 if ((c->listening_addr == NULL && addr != NULL) || 3840 (c->listening_addr != NULL && addr == NULL)) 3841 continue; 3842 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 3843 debug2_f("close channel %d", i); 3844 channel_free(ssh, c); 3845 found = 1; 3846 } 3847 } 3848 3849 return found; 3850 } 3851 3852 static int 3853 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 3854 { 3855 u_int i; 3856 int found = 0; 3857 3858 if (path == NULL) { 3859 error_f("no path specified."); 3860 return 0; 3861 } 3862 3863 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3864 Channel *c = ssh->chanctxt->channels[i]; 3865 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 3866 continue; 3867 if (c->listening_addr == NULL) 3868 continue; 3869 if (strcmp(c->listening_addr, path) == 0) { 3870 debug2_f("close channel %d", i); 3871 channel_free(ssh, c); 3872 found = 1; 3873 } 3874 } 3875 3876 return found; 3877 } 3878 3879 int 3880 channel_cancel_lport_listener(struct ssh *ssh, 3881 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 3882 { 3883 if (fwd->listen_path != NULL) { 3884 return channel_cancel_lport_listener_streamlocal(ssh, 3885 fwd->listen_path); 3886 } else { 3887 return channel_cancel_lport_listener_tcpip(ssh, 3888 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 3889 } 3890 } 3891 3892 /* protocol local port fwd, used by ssh */ 3893 int 3894 channel_setup_local_fwd_listener(struct ssh *ssh, 3895 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3896 { 3897 if (fwd->listen_path != NULL) { 3898 return channel_setup_fwd_listener_streamlocal(ssh, 3899 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 3900 } else { 3901 return channel_setup_fwd_listener_tcpip(ssh, 3902 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 3903 } 3904 } 3905 3906 /* Matches a remote forwarding permission against a requested forwarding */ 3907 static int 3908 remote_open_match(struct permission *allowed_open, struct Forward *fwd) 3909 { 3910 int ret; 3911 char *lhost; 3912 3913 /* XXX add ACLs for streamlocal */ 3914 if (fwd->listen_path != NULL) 3915 return 1; 3916 3917 if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) 3918 return 0; 3919 3920 if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && 3921 allowed_open->listen_port != fwd->listen_port) 3922 return 0; 3923 3924 /* Match hostnames case-insensitively */ 3925 lhost = xstrdup(fwd->listen_host); 3926 lowercase(lhost); 3927 ret = match_pattern(lhost, allowed_open->listen_host); 3928 free(lhost); 3929 3930 return ret; 3931 } 3932 3933 /* Checks whether a requested remote forwarding is permitted */ 3934 static int 3935 check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) 3936 { 3937 struct ssh_channels *sc = ssh->chanctxt; 3938 struct permission_set *pset = &sc->remote_perms; 3939 u_int i, permit, permit_adm = 1; 3940 struct permission *perm; 3941 3942 /* XXX apply GatewayPorts override before checking? */ 3943 3944 permit = pset->all_permitted; 3945 if (!permit) { 3946 for (i = 0; i < pset->num_permitted_user; i++) { 3947 perm = &pset->permitted_user[i]; 3948 if (remote_open_match(perm, fwd)) { 3949 permit = 1; 3950 break; 3951 } 3952 } 3953 } 3954 3955 if (pset->num_permitted_admin > 0) { 3956 permit_adm = 0; 3957 for (i = 0; i < pset->num_permitted_admin; i++) { 3958 perm = &pset->permitted_admin[i]; 3959 if (remote_open_match(perm, fwd)) { 3960 permit_adm = 1; 3961 break; 3962 } 3963 } 3964 } 3965 3966 return permit && permit_adm; 3967 } 3968 3969 /* protocol v2 remote port fwd, used by sshd */ 3970 int 3971 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 3972 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 3973 { 3974 if (!check_rfwd_permission(ssh, fwd)) { 3975 ssh_packet_send_debug(ssh, "port forwarding refused"); 3976 if (fwd->listen_path != NULL) 3977 /* XXX always allowed, see remote_open_match() */ 3978 logit("Received request from %.100s port %d to " 3979 "remote forward to path \"%.100s\", " 3980 "but the request was denied.", 3981 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 3982 fwd->listen_path); 3983 else if(fwd->listen_host != NULL) 3984 logit("Received request from %.100s port %d to " 3985 "remote forward to host %.100s port %d, " 3986 "but the request was denied.", 3987 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 3988 fwd->listen_host, fwd->listen_port ); 3989 else 3990 logit("Received request from %.100s port %d to remote " 3991 "forward, but the request was denied.", 3992 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 3993 return 0; 3994 } 3995 if (fwd->listen_path != NULL) { 3996 return channel_setup_fwd_listener_streamlocal(ssh, 3997 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 3998 } else { 3999 return channel_setup_fwd_listener_tcpip(ssh, 4000 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 4001 fwd_opts); 4002 } 4003 } 4004 4005 /* 4006 * Translate the requested rfwd listen host to something usable for 4007 * this server. 4008 */ 4009 static const char * 4010 channel_rfwd_bind_host(const char *listen_host) 4011 { 4012 if (listen_host == NULL) { 4013 return "localhost"; 4014 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 4015 return ""; 4016 } else 4017 return listen_host; 4018 } 4019 4020 /* 4021 * Initiate forwarding of connections to port "port" on remote host through 4022 * the secure channel to host:port from local side. 4023 * Returns handle (index) for updating the dynamic listen port with 4024 * channel_update_permission(). 4025 */ 4026 int 4027 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 4028 { 4029 int r, success = 0, idx = -1; 4030 char *host_to_connect, *listen_host, *listen_path; 4031 int port_to_connect, listen_port; 4032 4033 /* Send the forward request to the remote side. */ 4034 if (fwd->listen_path != NULL) { 4035 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4036 (r = sshpkt_put_cstring(ssh, 4037 "streamlocal-forward@openssh.com")) != 0 || 4038 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4039 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 4040 (r = sshpkt_send(ssh)) != 0 || 4041 (r = ssh_packet_write_wait(ssh)) != 0) 4042 fatal_fr(r, "request streamlocal"); 4043 } else { 4044 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4045 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 4046 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 4047 (r = sshpkt_put_cstring(ssh, 4048 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 4049 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 4050 (r = sshpkt_send(ssh)) != 0 || 4051 (r = ssh_packet_write_wait(ssh)) != 0) 4052 fatal_fr(r, "request tcpip-forward"); 4053 } 4054 /* Assume that server accepts the request */ 4055 success = 1; 4056 if (success) { 4057 /* Record that connection to this host/port is permitted. */ 4058 host_to_connect = listen_host = listen_path = NULL; 4059 port_to_connect = listen_port = 0; 4060 if (fwd->connect_path != NULL) { 4061 host_to_connect = xstrdup(fwd->connect_path); 4062 port_to_connect = PORT_STREAMLOCAL; 4063 } else { 4064 host_to_connect = xstrdup(fwd->connect_host); 4065 port_to_connect = fwd->connect_port; 4066 } 4067 if (fwd->listen_path != NULL) { 4068 listen_path = xstrdup(fwd->listen_path); 4069 listen_port = PORT_STREAMLOCAL; 4070 } else { 4071 if (fwd->listen_host != NULL) 4072 listen_host = xstrdup(fwd->listen_host); 4073 listen_port = fwd->listen_port; 4074 } 4075 idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, 4076 host_to_connect, port_to_connect, 4077 listen_host, listen_path, listen_port, NULL); 4078 } 4079 return idx; 4080 } 4081 4082 static int 4083 open_match(struct permission *allowed_open, const char *requestedhost, 4084 int requestedport) 4085 { 4086 if (allowed_open->host_to_connect == NULL) 4087 return 0; 4088 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 4089 allowed_open->port_to_connect != requestedport) 4090 return 0; 4091 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 4092 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 4093 return 0; 4094 return 1; 4095 } 4096 4097 /* 4098 * Note that in the listen host/port case 4099 * we don't support FWD_PERMIT_ANY_PORT and 4100 * need to translate between the configured-host (listen_host) 4101 * and what we've sent to the remote server (channel_rfwd_bind_host) 4102 */ 4103 static int 4104 open_listen_match_tcpip(struct permission *allowed_open, 4105 const char *requestedhost, u_short requestedport, int translate) 4106 { 4107 const char *allowed_host; 4108 4109 if (allowed_open->host_to_connect == NULL) 4110 return 0; 4111 if (allowed_open->listen_port != requestedport) 4112 return 0; 4113 if (!translate && allowed_open->listen_host == NULL && 4114 requestedhost == NULL) 4115 return 1; 4116 allowed_host = translate ? 4117 channel_rfwd_bind_host(allowed_open->listen_host) : 4118 allowed_open->listen_host; 4119 if (allowed_host == NULL || requestedhost == NULL || 4120 strcmp(allowed_host, requestedhost) != 0) 4121 return 0; 4122 return 1; 4123 } 4124 4125 static int 4126 open_listen_match_streamlocal(struct permission *allowed_open, 4127 const char *requestedpath) 4128 { 4129 if (allowed_open->host_to_connect == NULL) 4130 return 0; 4131 if (allowed_open->listen_port != PORT_STREAMLOCAL) 4132 return 0; 4133 if (allowed_open->listen_path == NULL || 4134 strcmp(allowed_open->listen_path, requestedpath) != 0) 4135 return 0; 4136 return 1; 4137 } 4138 4139 /* 4140 * Request cancellation of remote forwarding of connection host:port from 4141 * local side. 4142 */ 4143 static int 4144 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 4145 const char *host, u_short port) 4146 { 4147 struct ssh_channels *sc = ssh->chanctxt; 4148 struct permission_set *pset = &sc->local_perms; 4149 int r; 4150 u_int i; 4151 struct permission *perm = NULL; 4152 4153 for (i = 0; i < pset->num_permitted_user; i++) { 4154 perm = &pset->permitted_user[i]; 4155 if (open_listen_match_tcpip(perm, host, port, 0)) 4156 break; 4157 perm = NULL; 4158 } 4159 if (perm == NULL) { 4160 debug_f("requested forward not found"); 4161 return -1; 4162 } 4163 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4164 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 4165 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4166 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 4167 (r = sshpkt_put_u32(ssh, port)) != 0 || 4168 (r = sshpkt_send(ssh)) != 0) 4169 fatal_fr(r, "send cancel"); 4170 4171 fwd_perm_clear(perm); /* unregister */ 4172 4173 return 0; 4174 } 4175 4176 /* 4177 * Request cancellation of remote forwarding of Unix domain socket 4178 * path from local side. 4179 */ 4180 static int 4181 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 4182 { 4183 struct ssh_channels *sc = ssh->chanctxt; 4184 struct permission_set *pset = &sc->local_perms; 4185 int r; 4186 u_int i; 4187 struct permission *perm = NULL; 4188 4189 for (i = 0; i < pset->num_permitted_user; i++) { 4190 perm = &pset->permitted_user[i]; 4191 if (open_listen_match_streamlocal(perm, path)) 4192 break; 4193 perm = NULL; 4194 } 4195 if (perm == NULL) { 4196 debug_f("requested forward not found"); 4197 return -1; 4198 } 4199 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 4200 (r = sshpkt_put_cstring(ssh, 4201 "cancel-streamlocal-forward@openssh.com")) != 0 || 4202 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 4203 (r = sshpkt_put_cstring(ssh, path)) != 0 || 4204 (r = sshpkt_send(ssh)) != 0) 4205 fatal_fr(r, "send cancel"); 4206 4207 fwd_perm_clear(perm); /* unregister */ 4208 4209 return 0; 4210 } 4211 4212 /* 4213 * Request cancellation of remote forwarding of a connection from local side. 4214 */ 4215 int 4216 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 4217 { 4218 if (fwd->listen_path != NULL) { 4219 return channel_request_rforward_cancel_streamlocal(ssh, 4220 fwd->listen_path); 4221 } else { 4222 return channel_request_rforward_cancel_tcpip(ssh, 4223 fwd->listen_host, 4224 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 4225 } 4226 } 4227 4228 /* 4229 * Permits opening to any host/port if permitted_user[] is empty. This is 4230 * usually called by the server, because the user could connect to any port 4231 * anyway, and the server has no way to know but to trust the client anyway. 4232 */ 4233 void 4234 channel_permit_all(struct ssh *ssh, int where) 4235 { 4236 struct permission_set *pset = permission_set_get(ssh, where); 4237 4238 if (pset->num_permitted_user == 0) 4239 pset->all_permitted = 1; 4240 } 4241 4242 /* 4243 * Permit the specified host/port for forwarding. 4244 */ 4245 void 4246 channel_add_permission(struct ssh *ssh, int who, int where, 4247 char *host, int port) 4248 { 4249 int local = where == FORWARD_LOCAL; 4250 struct permission_set *pset = permission_set_get(ssh, where); 4251 4252 debug("allow %s forwarding to host %s port %d", 4253 fwd_ident(who, where), host, port); 4254 /* 4255 * Remote forwards set listen_host/port, local forwards set 4256 * host/port_to_connect. 4257 */ 4258 permission_set_add(ssh, who, where, 4259 local ? host : 0, local ? port : 0, 4260 local ? NULL : host, NULL, local ? 0 : port, NULL); 4261 pset->all_permitted = 0; 4262 } 4263 4264 /* 4265 * Administratively disable forwarding. 4266 */ 4267 void 4268 channel_disable_admin(struct ssh *ssh, int where) 4269 { 4270 channel_clear_permission(ssh, FORWARD_ADM, where); 4271 permission_set_add(ssh, FORWARD_ADM, where, 4272 NULL, 0, NULL, NULL, 0, NULL); 4273 } 4274 4275 /* 4276 * Clear a list of permitted opens. 4277 */ 4278 void 4279 channel_clear_permission(struct ssh *ssh, int who, int where) 4280 { 4281 struct permission **permp; 4282 u_int *npermp; 4283 4284 permission_set_get_array(ssh, who, where, &permp, &npermp); 4285 *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); 4286 *npermp = 0; 4287 } 4288 4289 /* 4290 * Update the listen port for a dynamic remote forward, after 4291 * the actual 'newport' has been allocated. If 'newport' < 0 is 4292 * passed then they entry will be invalidated. 4293 */ 4294 void 4295 channel_update_permission(struct ssh *ssh, int idx, int newport) 4296 { 4297 struct permission_set *pset = &ssh->chanctxt->local_perms; 4298 4299 if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { 4300 debug_f("index out of range: %d num_permitted_user %d", 4301 idx, pset->num_permitted_user); 4302 return; 4303 } 4304 debug("%s allowed port %d for forwarding to host %s port %d", 4305 newport > 0 ? "Updating" : "Removing", 4306 newport, 4307 pset->permitted_user[idx].host_to_connect, 4308 pset->permitted_user[idx].port_to_connect); 4309 if (newport <= 0) 4310 fwd_perm_clear(&pset->permitted_user[idx]); 4311 else { 4312 pset->permitted_user[idx].listen_port = 4313 (ssh->compat & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 4314 } 4315 } 4316 4317 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 4318 int 4319 permitopen_port(const char *p) 4320 { 4321 int port; 4322 4323 if (strcmp(p, "*") == 0) 4324 return FWD_PERMIT_ANY_PORT; 4325 if ((port = a2port(p)) > 0) 4326 return port; 4327 return -1; 4328 } 4329 4330 /* Try to start non-blocking connect to next host in cctx list */ 4331 static int 4332 connect_next(struct channel_connect *cctx) 4333 { 4334 int sock, saved_errno; 4335 struct sockaddr_un *sunaddr; 4336 char ntop[NI_MAXHOST]; 4337 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 4338 4339 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 4340 switch (cctx->ai->ai_family) { 4341 case AF_UNIX: 4342 /* unix:pathname instead of host:port */ 4343 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 4344 strlcpy(ntop, "unix", sizeof(ntop)); 4345 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 4346 break; 4347 case AF_INET: 4348 case AF_INET6: 4349 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 4350 ntop, sizeof(ntop), strport, sizeof(strport), 4351 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 4352 error("connect_next: getnameinfo failed"); 4353 continue; 4354 } 4355 break; 4356 default: 4357 continue; 4358 } 4359 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 4360 cctx->ai->ai_protocol)) == -1) { 4361 if (cctx->ai->ai_next == NULL) 4362 error("socket: %.100s", strerror(errno)); 4363 else 4364 verbose("socket: %.100s", strerror(errno)); 4365 continue; 4366 } 4367 if (set_nonblock(sock) == -1) 4368 fatal_f("set_nonblock(%d)", sock); 4369 if (connect(sock, cctx->ai->ai_addr, 4370 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 4371 debug("connect_next: host %.100s ([%.100s]:%s): " 4372 "%.100s", cctx->host, ntop, strport, 4373 strerror(errno)); 4374 saved_errno = errno; 4375 close(sock); 4376 errno = saved_errno; 4377 continue; /* fail -- try next */ 4378 } 4379 if (cctx->ai->ai_family != AF_UNIX) 4380 set_nodelay(sock); 4381 debug("connect_next: host %.100s ([%.100s]:%s) " 4382 "in progress, fd=%d", cctx->host, ntop, strport, sock); 4383 cctx->ai = cctx->ai->ai_next; 4384 return sock; 4385 } 4386 return -1; 4387 } 4388 4389 static void 4390 channel_connect_ctx_free(struct channel_connect *cctx) 4391 { 4392 free(cctx->host); 4393 if (cctx->aitop) { 4394 if (cctx->aitop->ai_family == AF_UNIX) 4395 free(cctx->aitop); 4396 else 4397 freeaddrinfo(cctx->aitop); 4398 } 4399 memset(cctx, 0, sizeof(*cctx)); 4400 } 4401 4402 /* 4403 * Return connecting socket to remote host:port or local socket path, 4404 * passing back the failure reason if appropriate. 4405 */ 4406 static int 4407 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4408 char *ctype, char *rname, struct channel_connect *cctx, 4409 int *reason, const char **errmsg) 4410 { 4411 struct addrinfo hints; 4412 int gaierr; 4413 int sock = -1; 4414 char strport[NI_MAXSERV]; 4415 4416 if (port == PORT_STREAMLOCAL) { 4417 struct sockaddr_un *sunaddr; 4418 struct addrinfo *ai; 4419 4420 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4421 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4422 return -1; 4423 } 4424 4425 /* 4426 * Fake up a struct addrinfo for AF_UNIX connections. 4427 * channel_connect_ctx_free() must check ai_family 4428 * and use free() not freeaddirinfo() for AF_UNIX. 4429 */ 4430 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4431 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4432 ai->ai_addr = (struct sockaddr *)(ai + 1); 4433 ai->ai_addrlen = sizeof(*sunaddr); 4434 ai->ai_family = AF_UNIX; 4435 ai->ai_socktype = socktype; 4436 ai->ai_protocol = PF_UNSPEC; 4437 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4438 sunaddr->sun_family = AF_UNIX; 4439 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4440 cctx->aitop = ai; 4441 } else { 4442 memset(&hints, 0, sizeof(hints)); 4443 hints.ai_family = ssh->chanctxt->IPv4or6; 4444 hints.ai_socktype = socktype; 4445 snprintf(strport, sizeof strport, "%d", port); 4446 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4447 != 0) { 4448 if (errmsg != NULL) 4449 *errmsg = ssh_gai_strerror(gaierr); 4450 if (reason != NULL) 4451 *reason = SSH2_OPEN_CONNECT_FAILED; 4452 error("connect_to %.100s: unknown host (%s)", name, 4453 ssh_gai_strerror(gaierr)); 4454 return -1; 4455 } 4456 } 4457 4458 cctx->host = xstrdup(name); 4459 cctx->port = port; 4460 cctx->ai = cctx->aitop; 4461 4462 if ((sock = connect_next(cctx)) == -1) { 4463 error("connect to %.100s port %d failed: %s", 4464 name, port, strerror(errno)); 4465 return -1; 4466 } 4467 4468 return sock; 4469 } 4470 4471 /* Return CONNECTING channel to remote host:port or local socket path */ 4472 static Channel * 4473 connect_to(struct ssh *ssh, const char *host, int port, 4474 char *ctype, char *rname) 4475 { 4476 struct channel_connect cctx; 4477 Channel *c; 4478 int sock; 4479 4480 memset(&cctx, 0, sizeof(cctx)); 4481 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4482 &cctx, NULL, NULL); 4483 if (sock == -1) { 4484 channel_connect_ctx_free(&cctx); 4485 return NULL; 4486 } 4487 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4488 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4489 c->host_port = port; 4490 c->path = xstrdup(host); 4491 c->connect_ctx = cctx; 4492 4493 return c; 4494 } 4495 4496 /* 4497 * returns either the newly connected channel or the downstream channel 4498 * that needs to deal with this connection. 4499 */ 4500 Channel * 4501 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4502 u_short listen_port, char *ctype, char *rname) 4503 { 4504 struct ssh_channels *sc = ssh->chanctxt; 4505 struct permission_set *pset = &sc->local_perms; 4506 u_int i; 4507 struct permission *perm; 4508 4509 for (i = 0; i < pset->num_permitted_user; i++) { 4510 perm = &pset->permitted_user[i]; 4511 if (open_listen_match_tcpip(perm, 4512 listen_host, listen_port, 1)) { 4513 if (perm->downstream) 4514 return perm->downstream; 4515 if (perm->port_to_connect == 0) 4516 return rdynamic_connect_prepare(ssh, 4517 ctype, rname); 4518 return connect_to(ssh, 4519 perm->host_to_connect, perm->port_to_connect, 4520 ctype, rname); 4521 } 4522 } 4523 error("WARNING: Server requests forwarding for unknown listen_port %d", 4524 listen_port); 4525 return NULL; 4526 } 4527 4528 Channel * 4529 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4530 char *ctype, char *rname) 4531 { 4532 struct ssh_channels *sc = ssh->chanctxt; 4533 struct permission_set *pset = &sc->local_perms; 4534 u_int i; 4535 struct permission *perm; 4536 4537 for (i = 0; i < pset->num_permitted_user; i++) { 4538 perm = &pset->permitted_user[i]; 4539 if (open_listen_match_streamlocal(perm, path)) { 4540 return connect_to(ssh, 4541 perm->host_to_connect, perm->port_to_connect, 4542 ctype, rname); 4543 } 4544 } 4545 error("WARNING: Server requests forwarding for unknown path %.100s", 4546 path); 4547 return NULL; 4548 } 4549 4550 /* Check if connecting to that port is permitted and connect. */ 4551 Channel * 4552 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4553 char *ctype, char *rname, int *reason, const char **errmsg) 4554 { 4555 struct ssh_channels *sc = ssh->chanctxt; 4556 struct permission_set *pset = &sc->local_perms; 4557 struct channel_connect cctx; 4558 Channel *c; 4559 u_int i, permit, permit_adm = 1; 4560 int sock; 4561 struct permission *perm; 4562 4563 permit = pset->all_permitted; 4564 if (!permit) { 4565 for (i = 0; i < pset->num_permitted_user; i++) { 4566 perm = &pset->permitted_user[i]; 4567 if (open_match(perm, host, port)) { 4568 permit = 1; 4569 break; 4570 } 4571 } 4572 } 4573 4574 if (pset->num_permitted_admin > 0) { 4575 permit_adm = 0; 4576 for (i = 0; i < pset->num_permitted_admin; i++) { 4577 perm = &pset->permitted_admin[i]; 4578 if (open_match(perm, host, port)) { 4579 permit_adm = 1; 4580 break; 4581 } 4582 } 4583 } 4584 4585 if (!permit || !permit_adm) { 4586 logit("Received request from %.100s port %d to connect to " 4587 "host %.100s port %d, but the request was denied.", 4588 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), host, port); 4589 if (reason != NULL) 4590 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4591 return NULL; 4592 } 4593 4594 memset(&cctx, 0, sizeof(cctx)); 4595 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4596 &cctx, reason, errmsg); 4597 if (sock == -1) { 4598 channel_connect_ctx_free(&cctx); 4599 return NULL; 4600 } 4601 4602 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4603 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4604 c->host_port = port; 4605 c->path = xstrdup(host); 4606 c->connect_ctx = cctx; 4607 4608 return c; 4609 } 4610 4611 /* Check if connecting to that path is permitted and connect. */ 4612 Channel * 4613 channel_connect_to_path(struct ssh *ssh, const char *path, 4614 char *ctype, char *rname) 4615 { 4616 struct ssh_channels *sc = ssh->chanctxt; 4617 struct permission_set *pset = &sc->local_perms; 4618 u_int i, permit, permit_adm = 1; 4619 struct permission *perm; 4620 4621 permit = pset->all_permitted; 4622 if (!permit) { 4623 for (i = 0; i < pset->num_permitted_user; i++) { 4624 perm = &pset->permitted_user[i]; 4625 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4626 permit = 1; 4627 break; 4628 } 4629 } 4630 } 4631 4632 if (pset->num_permitted_admin > 0) { 4633 permit_adm = 0; 4634 for (i = 0; i < pset->num_permitted_admin; i++) { 4635 perm = &pset->permitted_admin[i]; 4636 if (open_match(perm, path, PORT_STREAMLOCAL)) { 4637 permit_adm = 1; 4638 break; 4639 } 4640 } 4641 } 4642 4643 if (!permit || !permit_adm) { 4644 logit("Received request to connect to path %.100s, " 4645 "but the request was denied.", path); 4646 return NULL; 4647 } 4648 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4649 } 4650 4651 void 4652 channel_send_window_changes(struct ssh *ssh) 4653 { 4654 struct ssh_channels *sc = ssh->chanctxt; 4655 struct winsize ws; 4656 int r; 4657 u_int i; 4658 4659 for (i = 0; i < sc->channels_alloc; i++) { 4660 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4661 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4662 continue; 4663 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) == -1) 4664 continue; 4665 channel_request_start(ssh, i, "window-change", 0); 4666 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4667 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4668 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4669 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4670 (r = sshpkt_send(ssh)) != 0) 4671 fatal_fr(r, "channel %u; send window-change", i); 4672 } 4673 } 4674 4675 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4676 static Channel * 4677 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4678 { 4679 Channel *c; 4680 int r; 4681 4682 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4683 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4684 c->host_port = 0; 4685 c->path = NULL; 4686 4687 /* 4688 * We need to open the channel before we have a FD, 4689 * so that we can get SOCKS header from peer. 4690 */ 4691 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4692 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4693 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4694 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4695 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) 4696 fatal_fr(r, "channel %i; confirm", c->self); 4697 return c; 4698 } 4699 4700 /* Return CONNECTING socket to remote host:port or local socket path */ 4701 static int 4702 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4703 { 4704 struct ssh_channels *sc = ssh->chanctxt; 4705 struct permission_set *pset = &sc->local_perms; 4706 struct permission *perm; 4707 struct channel_connect cctx; 4708 u_int i, permit_adm = 1; 4709 int sock; 4710 4711 if (pset->num_permitted_admin > 0) { 4712 permit_adm = 0; 4713 for (i = 0; i < pset->num_permitted_admin; i++) { 4714 perm = &pset->permitted_admin[i]; 4715 if (open_match(perm, c->path, c->host_port)) { 4716 permit_adm = 1; 4717 break; 4718 } 4719 } 4720 } 4721 if (!permit_adm) { 4722 debug_f("requested forward not permitted"); 4723 return -1; 4724 } 4725 4726 memset(&cctx, 0, sizeof(cctx)); 4727 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4728 NULL, &cctx, NULL, NULL); 4729 if (sock == -1) 4730 channel_connect_ctx_free(&cctx); 4731 else { 4732 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4733 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4734 c->connect_ctx = cctx; 4735 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4736 } 4737 return sock; 4738 } 4739 4740 /* -- X11 forwarding */ 4741 4742 /* 4743 * Creates an internet domain socket for listening for X11 connections. 4744 * Returns 0 and a suitable display number for the DISPLAY variable 4745 * stored in display_numberp , or -1 if an error occurs. 4746 */ 4747 int 4748 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4749 int x11_use_localhost, int single_connection, 4750 u_int *display_numberp, int **chanids) 4751 { 4752 Channel *nc = NULL; 4753 int display_number, sock; 4754 u_short port; 4755 struct addrinfo hints, *ai, *aitop; 4756 char strport[NI_MAXSERV]; 4757 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4758 4759 if (chanids == NULL) 4760 return -1; 4761 4762 for (display_number = x11_display_offset; 4763 display_number < MAX_DISPLAYS; 4764 display_number++) { 4765 port = 6000 + display_number; 4766 memset(&hints, 0, sizeof(hints)); 4767 hints.ai_family = ssh->chanctxt->IPv4or6; 4768 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4769 hints.ai_socktype = SOCK_STREAM; 4770 snprintf(strport, sizeof strport, "%d", port); 4771 if ((gaierr = getaddrinfo(NULL, strport, 4772 &hints, &aitop)) != 0) { 4773 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4774 return -1; 4775 } 4776 for (ai = aitop; ai; ai = ai->ai_next) { 4777 if (ai->ai_family != AF_INET && 4778 ai->ai_family != AF_INET6) 4779 continue; 4780 sock = socket(ai->ai_family, ai->ai_socktype, 4781 ai->ai_protocol); 4782 if (sock == -1) { 4783 error("socket: %.100s", strerror(errno)); 4784 freeaddrinfo(aitop); 4785 return -1; 4786 } 4787 set_reuseaddr(sock); 4788 if (bind(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4789 debug2_f("bind port %d: %.100s", port, 4790 strerror(errno)); 4791 close(sock); 4792 for (n = 0; n < num_socks; n++) 4793 close(socks[n]); 4794 num_socks = 0; 4795 break; 4796 } 4797 socks[num_socks++] = sock; 4798 if (num_socks == NUM_SOCKS) 4799 break; 4800 } 4801 freeaddrinfo(aitop); 4802 if (num_socks > 0) 4803 break; 4804 } 4805 if (display_number >= MAX_DISPLAYS) { 4806 error("Failed to allocate internet-domain X11 display socket."); 4807 return -1; 4808 } 4809 /* Start listening for connections on the socket. */ 4810 for (n = 0; n < num_socks; n++) { 4811 sock = socks[n]; 4812 if (listen(sock, SSH_LISTEN_BACKLOG) == -1) { 4813 error("listen: %.100s", strerror(errno)); 4814 close(sock); 4815 return -1; 4816 } 4817 } 4818 4819 /* Allocate a channel for each socket. */ 4820 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 4821 for (n = 0; n < num_socks; n++) { 4822 sock = socks[n]; 4823 nc = channel_new(ssh, "x11 listener", 4824 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4825 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 4826 0, "X11 inet listener", 1); 4827 nc->single_connection = single_connection; 4828 (*chanids)[n] = nc->self; 4829 } 4830 (*chanids)[n] = -1; 4831 4832 /* Return the display number for the DISPLAY environment variable. */ 4833 *display_numberp = display_number; 4834 return 0; 4835 } 4836 4837 static int 4838 connect_local_xsocket(u_int dnr) 4839 { 4840 int sock; 4841 struct sockaddr_un addr; 4842 4843 sock = socket(AF_UNIX, SOCK_STREAM, 0); 4844 if (sock == -1) 4845 error("socket: %.100s", strerror(errno)); 4846 memset(&addr, 0, sizeof(addr)); 4847 addr.sun_family = AF_UNIX; 4848 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 4849 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 4850 return sock; 4851 close(sock); 4852 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 4853 return -1; 4854 } 4855 4856 int 4857 x11_connect_display(struct ssh *ssh) 4858 { 4859 u_int display_number; 4860 const char *display; 4861 char buf[1024], *cp; 4862 struct addrinfo hints, *ai, *aitop; 4863 char strport[NI_MAXSERV]; 4864 int gaierr, sock = 0; 4865 4866 /* Try to open a socket for the local X server. */ 4867 display = getenv("DISPLAY"); 4868 if (!display) { 4869 error("DISPLAY not set."); 4870 return -1; 4871 } 4872 /* 4873 * Now we decode the value of the DISPLAY variable and make a 4874 * connection to the real X server. 4875 */ 4876 4877 /* 4878 * Check if it is a unix domain socket. Unix domain displays are in 4879 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 4880 */ 4881 if (strncmp(display, "unix:", 5) == 0 || 4882 display[0] == ':') { 4883 /* Connect to the unix domain socket. */ 4884 if (sscanf(strrchr(display, ':') + 1, "%u", 4885 &display_number) != 1) { 4886 error("Could not parse display number from DISPLAY: " 4887 "%.100s", display); 4888 return -1; 4889 } 4890 /* Create a socket. */ 4891 sock = connect_local_xsocket(display_number); 4892 if (sock < 0) 4893 return -1; 4894 4895 /* OK, we now have a connection to the display. */ 4896 return sock; 4897 } 4898 /* 4899 * Connect to an inet socket. The DISPLAY value is supposedly 4900 * hostname:d[.s], where hostname may also be numeric IP address. 4901 */ 4902 strlcpy(buf, display, sizeof(buf)); 4903 cp = strchr(buf, ':'); 4904 if (!cp) { 4905 error("Could not find ':' in DISPLAY: %.100s", display); 4906 return -1; 4907 } 4908 *cp = 0; 4909 /* 4910 * buf now contains the host name. But first we parse the 4911 * display number. 4912 */ 4913 if (sscanf(cp + 1, "%u", &display_number) != 1) { 4914 error("Could not parse display number from DISPLAY: %.100s", 4915 display); 4916 return -1; 4917 } 4918 4919 /* Look up the host address */ 4920 memset(&hints, 0, sizeof(hints)); 4921 hints.ai_family = ssh->chanctxt->IPv4or6; 4922 hints.ai_socktype = SOCK_STREAM; 4923 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 4924 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 4925 error("%.100s: unknown host. (%s)", buf, 4926 ssh_gai_strerror(gaierr)); 4927 return -1; 4928 } 4929 for (ai = aitop; ai; ai = ai->ai_next) { 4930 /* Create a socket. */ 4931 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 4932 if (sock == -1) { 4933 debug2("socket: %.100s", strerror(errno)); 4934 continue; 4935 } 4936 /* Connect it to the display. */ 4937 if (connect(sock, ai->ai_addr, ai->ai_addrlen) == -1) { 4938 debug2("connect %.100s port %u: %.100s", buf, 4939 6000 + display_number, strerror(errno)); 4940 close(sock); 4941 continue; 4942 } 4943 /* Success */ 4944 break; 4945 } 4946 freeaddrinfo(aitop); 4947 if (!ai) { 4948 error("connect %.100s port %u: %.100s", buf, 4949 6000 + display_number, strerror(errno)); 4950 return -1; 4951 } 4952 set_nodelay(sock); 4953 return sock; 4954 } 4955 4956 /* 4957 * Requests forwarding of X11 connections, generates fake authentication 4958 * data, and enables authentication spoofing. 4959 * This should be called in the client only. 4960 */ 4961 void 4962 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 4963 const char *disp, const char *proto, const char *data, int want_reply) 4964 { 4965 struct ssh_channels *sc = ssh->chanctxt; 4966 u_int data_len = (u_int) strlen(data) / 2; 4967 u_int i, value; 4968 const char *cp; 4969 char *new_data; 4970 int r, screen_number; 4971 4972 if (sc->x11_saved_display == NULL) 4973 sc->x11_saved_display = xstrdup(disp); 4974 else if (strcmp(disp, sc->x11_saved_display) != 0) { 4975 error("x11_request_forwarding_with_spoofing: different " 4976 "$DISPLAY already forwarded"); 4977 return; 4978 } 4979 4980 cp = strchr(disp, ':'); 4981 if (cp) 4982 cp = strchr(cp, '.'); 4983 if (cp) 4984 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 4985 else 4986 screen_number = 0; 4987 4988 if (sc->x11_saved_proto == NULL) { 4989 /* Save protocol name. */ 4990 sc->x11_saved_proto = xstrdup(proto); 4991 4992 /* Extract real authentication data. */ 4993 sc->x11_saved_data = xmalloc(data_len); 4994 for (i = 0; i < data_len; i++) { 4995 if (sscanf(data + 2 * i, "%2x", &value) != 1) { 4996 fatal("x11_request_forwarding: bad " 4997 "authentication data: %.100s", data); 4998 } 4999 sc->x11_saved_data[i] = value; 5000 } 5001 sc->x11_saved_data_len = data_len; 5002 5003 /* Generate fake data of the same length. */ 5004 sc->x11_fake_data = xmalloc(data_len); 5005 arc4random_buf(sc->x11_fake_data, data_len); 5006 sc->x11_fake_data_len = data_len; 5007 } 5008 5009 /* Convert the fake data into hex. */ 5010 new_data = tohex(sc->x11_fake_data, data_len); 5011 5012 /* Send the request packet. */ 5013 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 5014 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 5015 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 5016 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 5017 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 5018 (r = sshpkt_send(ssh)) != 0 || 5019 (r = ssh_packet_write_wait(ssh)) != 0) 5020 fatal_fr(r, "send x11-req"); 5021 free(new_data); 5022 } 5023