1 /* $OpenBSD: channels.c,v 1.380 2018/04/10 00:10:49 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 #include <sys/ioctl.h> 45 #include <sys/un.h> 46 #include <sys/socket.h> 47 #include <sys/time.h> 48 #include <sys/queue.h> 49 50 #include <netinet/in.h> 51 #include <arpa/inet.h> 52 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <limits.h> 56 #include <netdb.h> 57 #include <stdarg.h> 58 #include <stdint.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <termios.h> 63 #include <unistd.h> 64 65 #include "xmalloc.h" 66 #include "ssh.h" 67 #include "ssh2.h" 68 #include "ssherr.h" 69 #include "sshbuf.h" 70 #include "packet.h" 71 #include "log.h" 72 #include "misc.h" 73 #include "channels.h" 74 #include "compat.h" 75 #include "canohost.h" 76 #include "key.h" 77 #include "authfd.h" 78 #include "pathnames.h" 79 80 /* -- agent forwarding */ 81 #define NUM_SOCKS 10 82 83 /* -- tcp forwarding */ 84 /* special-case port number meaning allow any port */ 85 #define FWD_PERMIT_ANY_PORT 0 86 87 /* special-case wildcard meaning allow any host */ 88 #define FWD_PERMIT_ANY_HOST "*" 89 90 /* -- X11 forwarding */ 91 /* Maximum number of fake X11 displays to try. */ 92 #define MAX_DISPLAYS 1000 93 94 /* 95 * Data structure for storing which hosts are permitted for forward requests. 96 * The local sides of any remote forwards are stored in this array to prevent 97 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 98 * network (which might be behind a firewall). 99 */ 100 /* XXX: streamlocal wants a path instead of host:port */ 101 /* Overload host_to_connect; we could just make this match Forward */ 102 /* XXX - can we use listen_host instead of listen_path? */ 103 typedef struct { 104 char *host_to_connect; /* Connect to 'host'. */ 105 int port_to_connect; /* Connect to 'port'. */ 106 char *listen_host; /* Remote side should listen address. */ 107 char *listen_path; /* Remote side should listen path. */ 108 int listen_port; /* Remote side should listen port. */ 109 Channel *downstream; /* Downstream mux*/ 110 } ForwardPermission; 111 112 typedef void chan_fn(struct ssh *, Channel *c, 113 fd_set *readset, fd_set *writeset); 114 115 /* Master structure for channels state */ 116 struct ssh_channels { 117 /* 118 * Pointer to an array containing all allocated channels. The array 119 * is dynamically extended as needed. 120 */ 121 Channel **channels; 122 123 /* 124 * Size of the channel array. All slots of the array must always be 125 * initialized (at least the type field); unused slots set to NULL 126 */ 127 u_int channels_alloc; 128 129 /* 130 * Maximum file descriptor value used in any of the channels. This is 131 * updated in channel_new. 132 */ 133 int channel_max_fd; 134 135 /* 136 * 'channel_pre*' are called just before select() to add any bits 137 * relevant to channels in the select bitmasks. 138 * 139 * 'channel_post*': perform any appropriate operations for 140 * channels which have events pending. 141 */ 142 chan_fn **channel_pre; 143 chan_fn **channel_post; 144 145 /* -- tcp forwarding */ 146 147 /* List of all permitted host/port pairs to connect by the user. */ 148 ForwardPermission *permitted_opens; 149 150 /* List of all permitted host/port pairs to connect by the admin. */ 151 ForwardPermission *permitted_adm_opens; 152 153 /* 154 * Number of permitted host/port pairs in the array permitted by 155 * the user. 156 */ 157 u_int num_permitted_opens; 158 159 /* 160 * Number of permitted host/port pair in the array permitted by 161 * the admin. 162 */ 163 u_int num_adm_permitted_opens; 164 165 /* 166 * If this is true, all opens are permitted. This is the case on 167 * the server on which we have to trust the client anyway, and the 168 * user could do anything after logging in anyway. 169 */ 170 int all_opens_permitted; 171 172 /* -- X11 forwarding */ 173 174 /* Saved X11 local (client) display. */ 175 char *x11_saved_display; 176 177 /* Saved X11 authentication protocol name. */ 178 char *x11_saved_proto; 179 180 /* Saved X11 authentication data. This is the real data. */ 181 char *x11_saved_data; 182 u_int x11_saved_data_len; 183 184 /* Deadline after which all X11 connections are refused */ 185 u_int x11_refuse_time; 186 187 /* 188 * Fake X11 authentication data. This is what the server will be 189 * sending us; we should replace any occurrences of this by the 190 * real data. 191 */ 192 u_char *x11_fake_data; 193 u_int x11_fake_data_len; 194 195 /* AF_UNSPEC or AF_INET or AF_INET6 */ 196 int IPv4or6; 197 }; 198 199 /* helper */ 200 static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype); 201 static const char *channel_rfwd_bind_host(const char *listen_host); 202 203 /* non-blocking connect helpers */ 204 static int connect_next(struct channel_connect *); 205 static void channel_connect_ctx_free(struct channel_connect *); 206 static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *); 207 static int rdynamic_connect_finish(struct ssh *, Channel *); 208 209 /* Setup helper */ 210 static void channel_handler_init(struct ssh_channels *sc); 211 212 /* -- channel core */ 213 214 void 215 channel_init_channels(struct ssh *ssh) 216 { 217 struct ssh_channels *sc; 218 219 if ((sc = calloc(1, sizeof(*sc))) == NULL || 220 (sc->channel_pre = calloc(SSH_CHANNEL_MAX_TYPE, 221 sizeof(*sc->channel_pre))) == NULL || 222 (sc->channel_post = calloc(SSH_CHANNEL_MAX_TYPE, 223 sizeof(*sc->channel_post))) == NULL) 224 fatal("%s: allocation failed", __func__); 225 sc->channels_alloc = 10; 226 sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels)); 227 sc->IPv4or6 = AF_UNSPEC; 228 channel_handler_init(sc); 229 230 ssh->chanctxt = sc; 231 } 232 233 Channel * 234 channel_by_id(struct ssh *ssh, int id) 235 { 236 Channel *c; 237 238 if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) { 239 logit("%s: %d: bad id", __func__, id); 240 return NULL; 241 } 242 c = ssh->chanctxt->channels[id]; 243 if (c == NULL) { 244 logit("%s: %d: bad id: channel free", __func__, id); 245 return NULL; 246 } 247 return c; 248 } 249 250 Channel * 251 channel_by_remote_id(struct ssh *ssh, u_int remote_id) 252 { 253 Channel *c; 254 u_int i; 255 256 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 257 c = ssh->chanctxt->channels[i]; 258 if (c != NULL && c->have_remote_id && c->remote_id == remote_id) 259 return c; 260 } 261 return NULL; 262 } 263 264 /* 265 * Returns the channel if it is allowed to receive protocol messages. 266 * Private channels, like listening sockets, may not receive messages. 267 */ 268 Channel * 269 channel_lookup(struct ssh *ssh, int id) 270 { 271 Channel *c; 272 273 if ((c = channel_by_id(ssh, id)) == NULL) 274 return NULL; 275 276 switch (c->type) { 277 case SSH_CHANNEL_X11_OPEN: 278 case SSH_CHANNEL_LARVAL: 279 case SSH_CHANNEL_CONNECTING: 280 case SSH_CHANNEL_DYNAMIC: 281 case SSH_CHANNEL_RDYNAMIC_OPEN: 282 case SSH_CHANNEL_RDYNAMIC_FINISH: 283 case SSH_CHANNEL_OPENING: 284 case SSH_CHANNEL_OPEN: 285 case SSH_CHANNEL_ABANDONED: 286 case SSH_CHANNEL_MUX_PROXY: 287 return c; 288 } 289 logit("Non-public channel %d, type %d.", id, c->type); 290 return NULL; 291 } 292 293 /* 294 * Register filedescriptors for a channel, used when allocating a channel or 295 * when the channel consumer/producer is ready, e.g. shell exec'd 296 */ 297 static void 298 channel_register_fds(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd, 299 int extusage, int nonblock, int is_tty) 300 { 301 struct ssh_channels *sc = ssh->chanctxt; 302 303 /* Update the maximum file descriptor value. */ 304 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, rfd); 305 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, wfd); 306 sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, efd); 307 308 if (rfd != -1) 309 fcntl(rfd, F_SETFD, FD_CLOEXEC); 310 if (wfd != -1 && wfd != rfd) 311 fcntl(wfd, F_SETFD, FD_CLOEXEC); 312 if (efd != -1 && efd != rfd && efd != wfd) 313 fcntl(efd, F_SETFD, FD_CLOEXEC); 314 315 c->rfd = rfd; 316 c->wfd = wfd; 317 c->sock = (rfd == wfd) ? rfd : -1; 318 c->efd = efd; 319 c->extended_usage = extusage; 320 321 if ((c->isatty = is_tty) != 0) 322 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 323 324 /* enable nonblocking mode */ 325 if (nonblock) { 326 if (rfd != -1) 327 set_nonblock(rfd); 328 if (wfd != -1) 329 set_nonblock(wfd); 330 if (efd != -1) 331 set_nonblock(efd); 332 } 333 } 334 335 /* 336 * Allocate a new channel object and set its type and socket. This will cause 337 * remote_name to be freed. 338 */ 339 Channel * 340 channel_new(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd, 341 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) 342 { 343 struct ssh_channels *sc = ssh->chanctxt; 344 u_int i, found; 345 Channel *c; 346 347 /* Try to find a free slot where to put the new channel. */ 348 for (i = 0; i < sc->channels_alloc; i++) { 349 if (sc->channels[i] == NULL) { 350 /* Found a free slot. */ 351 found = i; 352 break; 353 } 354 } 355 if (i >= sc->channels_alloc) { 356 /* 357 * There are no free slots. Take last+1 slot and expand 358 * the array. 359 */ 360 found = sc->channels_alloc; 361 if (sc->channels_alloc > CHANNELS_MAX_CHANNELS) 362 fatal("%s: internal error: channels_alloc %d too big", 363 __func__, sc->channels_alloc); 364 sc->channels = xrecallocarray(sc->channels, sc->channels_alloc, 365 sc->channels_alloc + 10, sizeof(*sc->channels)); 366 sc->channels_alloc += 10; 367 debug2("channel: expanding %d", sc->channels_alloc); 368 } 369 /* Initialize and return new channel. */ 370 c = sc->channels[found] = xcalloc(1, sizeof(Channel)); 371 if ((c->input = sshbuf_new()) == NULL || 372 (c->output = sshbuf_new()) == NULL || 373 (c->extended = sshbuf_new()) == NULL) 374 fatal("%s: sshbuf_new failed", __func__); 375 c->ostate = CHAN_OUTPUT_OPEN; 376 c->istate = CHAN_INPUT_OPEN; 377 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, 0); 378 c->self = found; 379 c->type = type; 380 c->ctype = ctype; 381 c->local_window = window; 382 c->local_window_max = window; 383 c->local_maxpacket = maxpack; 384 c->remote_name = xstrdup(remote_name); 385 c->ctl_chan = -1; 386 c->delayed = 1; /* prevent call to channel_post handler */ 387 TAILQ_INIT(&c->status_confirms); 388 debug("channel %d: new [%s]", found, remote_name); 389 return c; 390 } 391 392 static void 393 channel_find_maxfd(struct ssh_channels *sc) 394 { 395 u_int i; 396 int max = 0; 397 Channel *c; 398 399 for (i = 0; i < sc->channels_alloc; i++) { 400 c = sc->channels[i]; 401 if (c != NULL) { 402 max = MAXIMUM(max, c->rfd); 403 max = MAXIMUM(max, c->wfd); 404 max = MAXIMUM(max, c->efd); 405 } 406 } 407 sc->channel_max_fd = max; 408 } 409 410 int 411 channel_close_fd(struct ssh *ssh, int *fdp) 412 { 413 struct ssh_channels *sc = ssh->chanctxt; 414 int ret = 0, fd = *fdp; 415 416 if (fd != -1) { 417 ret = close(fd); 418 *fdp = -1; 419 if (fd == sc->channel_max_fd) 420 channel_find_maxfd(sc); 421 } 422 return ret; 423 } 424 425 /* Close all channel fd/socket. */ 426 static void 427 channel_close_fds(struct ssh *ssh, Channel *c) 428 { 429 int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd; 430 431 channel_close_fd(ssh, &c->sock); 432 if (rfd != sock) 433 channel_close_fd(ssh, &c->rfd); 434 if (wfd != sock && wfd != rfd) 435 channel_close_fd(ssh, &c->wfd); 436 if (efd != sock && efd != rfd && efd != wfd) 437 channel_close_fd(ssh, &c->efd); 438 } 439 440 static void 441 fwd_perm_clear(ForwardPermission *fp) 442 { 443 free(fp->host_to_connect); 444 free(fp->listen_host); 445 free(fp->listen_path); 446 bzero(fp, sizeof(*fp)); 447 } 448 449 enum { FWDPERM_USER, FWDPERM_ADMIN }; 450 451 static int 452 fwd_perm_list_add(struct ssh *ssh, int which, 453 const char *host_to_connect, int port_to_connect, 454 const char *listen_host, const char *listen_path, int listen_port, 455 Channel *downstream) 456 { 457 ForwardPermission **fpl; 458 u_int n, *nfpl; 459 460 switch (which) { 461 case FWDPERM_USER: 462 fpl = &ssh->chanctxt->permitted_opens; 463 nfpl = &ssh->chanctxt->num_permitted_opens; 464 break; 465 case FWDPERM_ADMIN: 466 fpl = &ssh->chanctxt->permitted_adm_opens; 467 nfpl = &ssh->chanctxt->num_adm_permitted_opens; 468 break; 469 default: 470 fatal("%s: invalid list %d", __func__, which); 471 } 472 473 if (*nfpl >= INT_MAX) 474 fatal("%s: overflow", __func__); 475 476 *fpl = xrecallocarray(*fpl, *nfpl, *nfpl + 1, sizeof(**fpl)); 477 n = (*nfpl)++; 478 #define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s)) 479 (*fpl)[n].host_to_connect = MAYBE_DUP(host_to_connect); 480 (*fpl)[n].port_to_connect = port_to_connect; 481 (*fpl)[n].listen_host = MAYBE_DUP(listen_host); 482 (*fpl)[n].listen_path = MAYBE_DUP(listen_path); 483 (*fpl)[n].listen_port = listen_port; 484 (*fpl)[n].downstream = downstream; 485 #undef MAYBE_DUP 486 return (int)n; 487 } 488 489 static void 490 mux_remove_remote_forwardings(struct ssh *ssh, Channel *c) 491 { 492 struct ssh_channels *sc = ssh->chanctxt; 493 ForwardPermission *fp; 494 int r; 495 u_int i; 496 497 for (i = 0; i < sc->num_permitted_opens; i++) { 498 fp = &sc->permitted_opens[i]; 499 if (fp->downstream != c) 500 continue; 501 502 /* cancel on the server, since mux client is gone */ 503 debug("channel %d: cleanup remote forward for %s:%u", 504 c->self, fp->listen_host, fp->listen_port); 505 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 506 (r = sshpkt_put_cstring(ssh, 507 "cancel-tcpip-forward")) != 0 || 508 (r = sshpkt_put_u8(ssh, 0)) != 0 || 509 (r = sshpkt_put_cstring(ssh, 510 channel_rfwd_bind_host(fp->listen_host))) != 0 || 511 (r = sshpkt_put_u32(ssh, fp->listen_port)) != 0 || 512 (r = sshpkt_send(ssh)) != 0) { 513 fatal("%s: channel %i: %s", __func__, 514 c->self, ssh_err(r)); 515 } 516 fwd_perm_clear(fp); /* unregister */ 517 } 518 } 519 520 /* Free the channel and close its fd/socket. */ 521 void 522 channel_free(struct ssh *ssh, Channel *c) 523 { 524 struct ssh_channels *sc = ssh->chanctxt; 525 char *s; 526 u_int i, n; 527 Channel *other; 528 struct channel_confirm *cc; 529 530 for (n = 0, i = 0; i < sc->channels_alloc; i++) { 531 if ((other = sc->channels[i]) == NULL) 532 continue; 533 n++; 534 /* detach from mux client and prepare for closing */ 535 if (c->type == SSH_CHANNEL_MUX_CLIENT && 536 other->type == SSH_CHANNEL_MUX_PROXY && 537 other->mux_ctx == c) { 538 other->mux_ctx = NULL; 539 other->type = SSH_CHANNEL_OPEN; 540 other->istate = CHAN_INPUT_CLOSED; 541 other->ostate = CHAN_OUTPUT_CLOSED; 542 } 543 } 544 debug("channel %d: free: %s, nchannels %u", c->self, 545 c->remote_name ? c->remote_name : "???", n); 546 547 if (c->type == SSH_CHANNEL_MUX_CLIENT) 548 mux_remove_remote_forwardings(ssh, c); 549 550 s = channel_open_message(ssh); 551 debug3("channel %d: status: %s", c->self, s); 552 free(s); 553 554 channel_close_fds(ssh, c); 555 sshbuf_free(c->input); 556 sshbuf_free(c->output); 557 sshbuf_free(c->extended); 558 c->input = c->output = c->extended = NULL; 559 free(c->remote_name); 560 c->remote_name = NULL; 561 free(c->path); 562 c->path = NULL; 563 free(c->listening_addr); 564 c->listening_addr = NULL; 565 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 566 if (cc->abandon_cb != NULL) 567 cc->abandon_cb(ssh, c, cc->ctx); 568 TAILQ_REMOVE(&c->status_confirms, cc, entry); 569 explicit_bzero(cc, sizeof(*cc)); 570 free(cc); 571 } 572 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 573 c->filter_cleanup(ssh, c->self, c->filter_ctx); 574 sc->channels[c->self] = NULL; 575 explicit_bzero(c, sizeof(*c)); 576 free(c); 577 } 578 579 void 580 channel_free_all(struct ssh *ssh) 581 { 582 u_int i; 583 584 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 585 if (ssh->chanctxt->channels[i] != NULL) 586 channel_free(ssh, ssh->chanctxt->channels[i]); 587 } 588 589 /* 590 * Closes the sockets/fds of all channels. This is used to close extra file 591 * descriptors after a fork. 592 */ 593 void 594 channel_close_all(struct ssh *ssh) 595 { 596 u_int i; 597 598 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) 599 if (ssh->chanctxt->channels[i] != NULL) 600 channel_close_fds(ssh, ssh->chanctxt->channels[i]); 601 } 602 603 /* 604 * Stop listening to channels. 605 */ 606 void 607 channel_stop_listening(struct ssh *ssh) 608 { 609 u_int i; 610 Channel *c; 611 612 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 613 c = ssh->chanctxt->channels[i]; 614 if (c != NULL) { 615 switch (c->type) { 616 case SSH_CHANNEL_AUTH_SOCKET: 617 case SSH_CHANNEL_PORT_LISTENER: 618 case SSH_CHANNEL_RPORT_LISTENER: 619 case SSH_CHANNEL_X11_LISTENER: 620 case SSH_CHANNEL_UNIX_LISTENER: 621 case SSH_CHANNEL_RUNIX_LISTENER: 622 channel_close_fd(ssh, &c->sock); 623 channel_free(ssh, c); 624 break; 625 } 626 } 627 } 628 } 629 630 /* 631 * Returns true if no channel has too much buffered data, and false if one or 632 * more channel is overfull. 633 */ 634 int 635 channel_not_very_much_buffered_data(struct ssh *ssh) 636 { 637 u_int i; 638 u_int maxsize = ssh_packet_get_maxsize(ssh); 639 Channel *c; 640 641 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 642 c = ssh->chanctxt->channels[i]; 643 if (c == NULL || c->type != SSH_CHANNEL_OPEN) 644 continue; 645 if (sshbuf_len(c->output) > maxsize) { 646 debug2("channel %d: big output buffer %zu > %u", 647 c->self, sshbuf_len(c->output), maxsize); 648 return 0; 649 } 650 } 651 return 1; 652 } 653 654 /* Returns true if any channel is still open. */ 655 int 656 channel_still_open(struct ssh *ssh) 657 { 658 u_int i; 659 Channel *c; 660 661 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 662 c = ssh->chanctxt->channels[i]; 663 if (c == NULL) 664 continue; 665 switch (c->type) { 666 case SSH_CHANNEL_X11_LISTENER: 667 case SSH_CHANNEL_PORT_LISTENER: 668 case SSH_CHANNEL_RPORT_LISTENER: 669 case SSH_CHANNEL_MUX_LISTENER: 670 case SSH_CHANNEL_CLOSED: 671 case SSH_CHANNEL_AUTH_SOCKET: 672 case SSH_CHANNEL_DYNAMIC: 673 case SSH_CHANNEL_RDYNAMIC_OPEN: 674 case SSH_CHANNEL_CONNECTING: 675 case SSH_CHANNEL_ZOMBIE: 676 case SSH_CHANNEL_ABANDONED: 677 case SSH_CHANNEL_UNIX_LISTENER: 678 case SSH_CHANNEL_RUNIX_LISTENER: 679 continue; 680 case SSH_CHANNEL_LARVAL: 681 continue; 682 case SSH_CHANNEL_OPENING: 683 case SSH_CHANNEL_OPEN: 684 case SSH_CHANNEL_RDYNAMIC_FINISH: 685 case SSH_CHANNEL_X11_OPEN: 686 case SSH_CHANNEL_MUX_CLIENT: 687 case SSH_CHANNEL_MUX_PROXY: 688 return 1; 689 default: 690 fatal("%s: bad channel type %d", __func__, c->type); 691 /* NOTREACHED */ 692 } 693 } 694 return 0; 695 } 696 697 /* Returns the id of an open channel suitable for keepaliving */ 698 int 699 channel_find_open(struct ssh *ssh) 700 { 701 u_int i; 702 Channel *c; 703 704 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 705 c = ssh->chanctxt->channels[i]; 706 if (c == NULL || !c->have_remote_id) 707 continue; 708 switch (c->type) { 709 case SSH_CHANNEL_CLOSED: 710 case SSH_CHANNEL_DYNAMIC: 711 case SSH_CHANNEL_RDYNAMIC_OPEN: 712 case SSH_CHANNEL_RDYNAMIC_FINISH: 713 case SSH_CHANNEL_X11_LISTENER: 714 case SSH_CHANNEL_PORT_LISTENER: 715 case SSH_CHANNEL_RPORT_LISTENER: 716 case SSH_CHANNEL_MUX_LISTENER: 717 case SSH_CHANNEL_MUX_CLIENT: 718 case SSH_CHANNEL_MUX_PROXY: 719 case SSH_CHANNEL_OPENING: 720 case SSH_CHANNEL_CONNECTING: 721 case SSH_CHANNEL_ZOMBIE: 722 case SSH_CHANNEL_ABANDONED: 723 case SSH_CHANNEL_UNIX_LISTENER: 724 case SSH_CHANNEL_RUNIX_LISTENER: 725 continue; 726 case SSH_CHANNEL_LARVAL: 727 case SSH_CHANNEL_AUTH_SOCKET: 728 case SSH_CHANNEL_OPEN: 729 case SSH_CHANNEL_X11_OPEN: 730 return i; 731 default: 732 fatal("%s: bad channel type %d", __func__, c->type); 733 /* NOTREACHED */ 734 } 735 } 736 return -1; 737 } 738 739 /* 740 * Returns a message describing the currently open forwarded connections, 741 * suitable for sending to the client. The message contains crlf pairs for 742 * newlines. 743 */ 744 char * 745 channel_open_message(struct ssh *ssh) 746 { 747 struct sshbuf *buf; 748 Channel *c; 749 u_int i; 750 int r; 751 char *ret; 752 753 if ((buf = sshbuf_new()) == NULL) 754 fatal("%s: sshbuf_new", __func__); 755 if ((r = sshbuf_putf(buf, 756 "The following connections are open:\r\n")) != 0) 757 fatal("%s: sshbuf_putf: %s", __func__, ssh_err(r)); 758 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 759 c = ssh->chanctxt->channels[i]; 760 if (c == NULL) 761 continue; 762 switch (c->type) { 763 case SSH_CHANNEL_X11_LISTENER: 764 case SSH_CHANNEL_PORT_LISTENER: 765 case SSH_CHANNEL_RPORT_LISTENER: 766 case SSH_CHANNEL_CLOSED: 767 case SSH_CHANNEL_AUTH_SOCKET: 768 case SSH_CHANNEL_ZOMBIE: 769 case SSH_CHANNEL_ABANDONED: 770 case SSH_CHANNEL_MUX_LISTENER: 771 case SSH_CHANNEL_UNIX_LISTENER: 772 case SSH_CHANNEL_RUNIX_LISTENER: 773 continue; 774 case SSH_CHANNEL_LARVAL: 775 case SSH_CHANNEL_OPENING: 776 case SSH_CHANNEL_CONNECTING: 777 case SSH_CHANNEL_DYNAMIC: 778 case SSH_CHANNEL_RDYNAMIC_OPEN: 779 case SSH_CHANNEL_RDYNAMIC_FINISH: 780 case SSH_CHANNEL_OPEN: 781 case SSH_CHANNEL_X11_OPEN: 782 case SSH_CHANNEL_MUX_PROXY: 783 case SSH_CHANNEL_MUX_CLIENT: 784 if ((r = sshbuf_putf(buf, " #%d %.300s " 785 "(t%d %s%u i%u/%zu o%u/%zu fd %d/%d cc %d)\r\n", 786 c->self, c->remote_name, 787 c->type, 788 c->have_remote_id ? "r" : "nr", c->remote_id, 789 c->istate, sshbuf_len(c->input), 790 c->ostate, sshbuf_len(c->output), 791 c->rfd, c->wfd, c->ctl_chan)) != 0) 792 fatal("%s: sshbuf_putf: %s", 793 __func__, ssh_err(r)); 794 continue; 795 default: 796 fatal("%s: bad channel type %d", __func__, c->type); 797 /* NOTREACHED */ 798 } 799 } 800 if ((ret = sshbuf_dup_string(buf)) == NULL) 801 fatal("%s: sshbuf_dup_string", __func__); 802 sshbuf_free(buf); 803 return ret; 804 } 805 806 static void 807 open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type) 808 { 809 int r; 810 811 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 812 (r = sshpkt_put_cstring(ssh, type)) != 0 || 813 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 814 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 815 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 816 fatal("%s: channel %i: open: %s", where, c->self, ssh_err(r)); 817 } 818 } 819 820 void 821 channel_send_open(struct ssh *ssh, int id) 822 { 823 Channel *c = channel_lookup(ssh, id); 824 int r; 825 826 if (c == NULL) { 827 logit("channel_send_open: %d: bad id", id); 828 return; 829 } 830 debug2("channel %d: send open", id); 831 open_preamble(ssh, __func__, c, c->ctype); 832 if ((r = sshpkt_send(ssh)) != 0) 833 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 834 } 835 836 void 837 channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm) 838 { 839 Channel *c = channel_lookup(ssh, id); 840 int r; 841 842 if (c == NULL) { 843 logit("%s: %d: unknown channel id", __func__, id); 844 return; 845 } 846 if (!c->have_remote_id) 847 fatal(":%s: channel %d: no remote id", __func__, c->self); 848 849 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 850 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || 851 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 852 (r = sshpkt_put_cstring(ssh, service)) != 0 || 853 (r = sshpkt_put_u8(ssh, wantconfirm)) != 0) { 854 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 855 } 856 } 857 858 void 859 channel_register_status_confirm(struct ssh *ssh, int id, 860 channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx) 861 { 862 struct channel_confirm *cc; 863 Channel *c; 864 865 if ((c = channel_lookup(ssh, id)) == NULL) 866 fatal("%s: %d: bad id", __func__, id); 867 868 cc = xcalloc(1, sizeof(*cc)); 869 cc->cb = cb; 870 cc->abandon_cb = abandon_cb; 871 cc->ctx = ctx; 872 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 873 } 874 875 void 876 channel_register_open_confirm(struct ssh *ssh, int id, 877 channel_open_fn *fn, void *ctx) 878 { 879 Channel *c = channel_lookup(ssh, id); 880 881 if (c == NULL) { 882 logit("%s: %d: bad id", __func__, id); 883 return; 884 } 885 c->open_confirm = fn; 886 c->open_confirm_ctx = ctx; 887 } 888 889 void 890 channel_register_cleanup(struct ssh *ssh, int id, 891 channel_callback_fn *fn, int do_close) 892 { 893 Channel *c = channel_by_id(ssh, id); 894 895 if (c == NULL) { 896 logit("%s: %d: bad id", __func__, id); 897 return; 898 } 899 c->detach_user = fn; 900 c->detach_close = do_close; 901 } 902 903 void 904 channel_cancel_cleanup(struct ssh *ssh, int id) 905 { 906 Channel *c = channel_by_id(ssh, id); 907 908 if (c == NULL) { 909 logit("%s: %d: bad id", __func__, id); 910 return; 911 } 912 c->detach_user = NULL; 913 c->detach_close = 0; 914 } 915 916 void 917 channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, 918 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 919 { 920 Channel *c = channel_lookup(ssh, id); 921 922 if (c == NULL) { 923 logit("%s: %d: bad id", __func__, id); 924 return; 925 } 926 c->input_filter = ifn; 927 c->output_filter = ofn; 928 c->filter_ctx = ctx; 929 c->filter_cleanup = cfn; 930 } 931 932 void 933 channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, 934 int extusage, int nonblock, int is_tty, u_int window_max) 935 { 936 Channel *c = channel_lookup(ssh, id); 937 int r; 938 939 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 940 fatal("channel_activate for non-larval channel %d.", id); 941 if (!c->have_remote_id) 942 fatal(":%s: channel %d: no remote id", __func__, c->self); 943 944 channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); 945 c->type = SSH_CHANNEL_OPEN; 946 c->local_window = c->local_window_max = window_max; 947 948 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 949 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 950 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 951 (r = sshpkt_send(ssh)) != 0) 952 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 953 } 954 955 static void 956 channel_pre_listener(struct ssh *ssh, Channel *c, 957 fd_set *readset, fd_set *writeset) 958 { 959 FD_SET(c->sock, readset); 960 } 961 962 static void 963 channel_pre_connecting(struct ssh *ssh, Channel *c, 964 fd_set *readset, fd_set *writeset) 965 { 966 debug3("channel %d: waiting for connection", c->self); 967 FD_SET(c->sock, writeset); 968 } 969 970 static void 971 channel_pre_open(struct ssh *ssh, Channel *c, 972 fd_set *readset, fd_set *writeset) 973 { 974 if (c->istate == CHAN_INPUT_OPEN && 975 c->remote_window > 0 && 976 sshbuf_len(c->input) < c->remote_window && 977 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 978 FD_SET(c->rfd, readset); 979 if (c->ostate == CHAN_OUTPUT_OPEN || 980 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 981 if (sshbuf_len(c->output) > 0) { 982 FD_SET(c->wfd, writeset); 983 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 984 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 985 debug2("channel %d: " 986 "obuf_empty delayed efd %d/(%zu)", c->self, 987 c->efd, sshbuf_len(c->extended)); 988 else 989 chan_obuf_empty(ssh, c); 990 } 991 } 992 /** XXX check close conditions, too */ 993 if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && 994 c->ostate == CHAN_OUTPUT_CLOSED)) { 995 if (c->extended_usage == CHAN_EXTENDED_WRITE && 996 sshbuf_len(c->extended) > 0) 997 FD_SET(c->efd, writeset); 998 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 999 (c->extended_usage == CHAN_EXTENDED_READ || 1000 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1001 sshbuf_len(c->extended) < c->remote_window) 1002 FD_SET(c->efd, readset); 1003 } 1004 /* XXX: What about efd? races? */ 1005 } 1006 1007 /* 1008 * This is a special state for X11 authentication spoofing. An opened X11 1009 * connection (when authentication spoofing is being done) remains in this 1010 * state until the first packet has been completely read. The authentication 1011 * data in that packet is then substituted by the real data if it matches the 1012 * fake data, and the channel is put into normal mode. 1013 * XXX All this happens at the client side. 1014 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 1015 */ 1016 static int 1017 x11_open_helper(struct ssh *ssh, struct sshbuf *b) 1018 { 1019 struct ssh_channels *sc = ssh->chanctxt; 1020 u_char *ucp; 1021 u_int proto_len, data_len; 1022 1023 /* Is this being called after the refusal deadline? */ 1024 if (sc->x11_refuse_time != 0 && 1025 (u_int)monotime() >= sc->x11_refuse_time) { 1026 verbose("Rejected X11 connection after ForwardX11Timeout " 1027 "expired"); 1028 return -1; 1029 } 1030 1031 /* Check if the fixed size part of the packet is in buffer. */ 1032 if (sshbuf_len(b) < 12) 1033 return 0; 1034 1035 /* Parse the lengths of variable-length fields. */ 1036 ucp = sshbuf_mutable_ptr(b); 1037 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 1038 proto_len = 256 * ucp[6] + ucp[7]; 1039 data_len = 256 * ucp[8] + ucp[9]; 1040 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 1041 proto_len = ucp[6] + 256 * ucp[7]; 1042 data_len = ucp[8] + 256 * ucp[9]; 1043 } else { 1044 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 1045 ucp[0]); 1046 return -1; 1047 } 1048 1049 /* Check if the whole packet is in buffer. */ 1050 if (sshbuf_len(b) < 1051 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 1052 return 0; 1053 1054 /* Check if authentication protocol matches. */ 1055 if (proto_len != strlen(sc->x11_saved_proto) || 1056 memcmp(ucp + 12, sc->x11_saved_proto, proto_len) != 0) { 1057 debug2("X11 connection uses different authentication protocol."); 1058 return -1; 1059 } 1060 /* Check if authentication data matches our fake data. */ 1061 if (data_len != sc->x11_fake_data_len || 1062 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 1063 sc->x11_fake_data, sc->x11_fake_data_len) != 0) { 1064 debug2("X11 auth data does not match fake data."); 1065 return -1; 1066 } 1067 /* Check fake data length */ 1068 if (sc->x11_fake_data_len != sc->x11_saved_data_len) { 1069 error("X11 fake_data_len %d != saved_data_len %d", 1070 sc->x11_fake_data_len, sc->x11_saved_data_len); 1071 return -1; 1072 } 1073 /* 1074 * Received authentication protocol and data match 1075 * our fake data. Substitute the fake data with real 1076 * data. 1077 */ 1078 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 1079 sc->x11_saved_data, sc->x11_saved_data_len); 1080 return 1; 1081 } 1082 1083 static void 1084 channel_pre_x11_open(struct ssh *ssh, Channel *c, 1085 fd_set *readset, fd_set *writeset) 1086 { 1087 int ret = x11_open_helper(ssh, c->output); 1088 1089 /* c->force_drain = 1; */ 1090 1091 if (ret == 1) { 1092 c->type = SSH_CHANNEL_OPEN; 1093 channel_pre_open(ssh, c, readset, writeset); 1094 } else if (ret == -1) { 1095 logit("X11 connection rejected because of wrong authentication."); 1096 debug2("X11 rejected %d i%d/o%d", 1097 c->self, c->istate, c->ostate); 1098 chan_read_failed(ssh, c); 1099 sshbuf_reset(c->input); 1100 chan_ibuf_empty(ssh, c); 1101 sshbuf_reset(c->output); 1102 chan_write_failed(ssh, c); 1103 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1104 } 1105 } 1106 1107 static void 1108 channel_pre_mux_client(struct ssh *ssh, 1109 Channel *c, fd_set *readset, fd_set *writeset) 1110 { 1111 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1112 sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) 1113 FD_SET(c->rfd, readset); 1114 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1115 /* clear buffer immediately (discard any partial packet) */ 1116 sshbuf_reset(c->input); 1117 chan_ibuf_empty(ssh, c); 1118 /* Start output drain. XXX just kill chan? */ 1119 chan_rcvd_oclose(ssh, c); 1120 } 1121 if (c->ostate == CHAN_OUTPUT_OPEN || 1122 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1123 if (sshbuf_len(c->output) > 0) 1124 FD_SET(c->wfd, writeset); 1125 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1126 chan_obuf_empty(ssh, c); 1127 } 1128 } 1129 1130 /* try to decode a socks4 header */ 1131 static int 1132 channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) 1133 { 1134 const u_char *p; 1135 char *host; 1136 u_int len, have, i, found, need; 1137 char username[256]; 1138 struct { 1139 u_int8_t version; 1140 u_int8_t command; 1141 u_int16_t dest_port; 1142 struct in_addr dest_addr; 1143 } s4_req, s4_rsp; 1144 int r; 1145 1146 debug2("channel %d: decode socks4", c->self); 1147 1148 have = sshbuf_len(input); 1149 len = sizeof(s4_req); 1150 if (have < len) 1151 return 0; 1152 p = sshbuf_ptr(input); 1153 1154 need = 1; 1155 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1156 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1157 debug2("channel %d: socks4a request", c->self); 1158 /* ... and needs an extra string (the hostname) */ 1159 need = 2; 1160 } 1161 /* Check for terminating NUL on the string(s) */ 1162 for (found = 0, i = len; i < have; i++) { 1163 if (p[i] == '\0') { 1164 found++; 1165 if (found == need) 1166 break; 1167 } 1168 if (i > 1024) { 1169 /* the peer is probably sending garbage */ 1170 debug("channel %d: decode socks4: too long", 1171 c->self); 1172 return -1; 1173 } 1174 } 1175 if (found < need) 1176 return 0; 1177 if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || 1178 (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || 1179 (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || 1180 (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { 1181 debug("channels %d: decode socks4: %s", c->self, ssh_err(r)); 1182 return -1; 1183 } 1184 have = sshbuf_len(input); 1185 p = sshbuf_ptr(input); 1186 if (memchr(p, '\0', have) == NULL) { 1187 error("channel %d: decode socks4: user not nul terminated", 1188 c->self); 1189 return -1; 1190 } 1191 len = strlen(p); 1192 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1193 len++; /* trailing '\0' */ 1194 strlcpy(username, p, sizeof(username)); 1195 if ((r = sshbuf_consume(input, len)) != 0) { 1196 fatal("%s: channel %d: consume: %s", __func__, 1197 c->self, ssh_err(r)); 1198 } 1199 free(c->path); 1200 c->path = NULL; 1201 if (need == 1) { /* SOCKS4: one string */ 1202 host = inet_ntoa(s4_req.dest_addr); 1203 c->path = xstrdup(host); 1204 } else { /* SOCKS4A: two strings */ 1205 have = sshbuf_len(input); 1206 p = sshbuf_ptr(input); 1207 if (memchr(p, '\0', have) == NULL) { 1208 error("channel %d: decode socks4a: host not nul " 1209 "terminated", c->self); 1210 return -1; 1211 } 1212 len = strlen(p); 1213 debug2("channel %d: decode socks4a: host %s/%d", 1214 c->self, p, len); 1215 len++; /* trailing '\0' */ 1216 if (len > NI_MAXHOST) { 1217 error("channel %d: hostname \"%.100s\" too long", 1218 c->self, p); 1219 return -1; 1220 } 1221 c->path = xstrdup(p); 1222 if ((r = sshbuf_consume(input, len)) != 0) { 1223 fatal("%s: channel %d: consume: %s", __func__, 1224 c->self, ssh_err(r)); 1225 } 1226 } 1227 c->host_port = ntohs(s4_req.dest_port); 1228 1229 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1230 c->self, c->path, c->host_port, s4_req.command); 1231 1232 if (s4_req.command != 1) { 1233 debug("channel %d: cannot handle: %s cn %d", 1234 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1235 return -1; 1236 } 1237 s4_rsp.version = 0; /* vn: 0 for reply */ 1238 s4_rsp.command = 90; /* cd: req granted */ 1239 s4_rsp.dest_port = 0; /* ignored */ 1240 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1241 if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) { 1242 fatal("%s: channel %d: append reply: %s", __func__, 1243 c->self, ssh_err(r)); 1244 } 1245 return 1; 1246 } 1247 1248 /* try to decode a socks5 header */ 1249 #define SSH_SOCKS5_AUTHDONE 0x1000 1250 #define SSH_SOCKS5_NOAUTH 0x00 1251 #define SSH_SOCKS5_IPV4 0x01 1252 #define SSH_SOCKS5_DOMAIN 0x03 1253 #define SSH_SOCKS5_IPV6 0x04 1254 #define SSH_SOCKS5_CONNECT 0x01 1255 #define SSH_SOCKS5_SUCCESS 0x00 1256 1257 static int 1258 channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) 1259 { 1260 /* XXX use get/put_u8 instead of trusting struct padding */ 1261 struct { 1262 u_int8_t version; 1263 u_int8_t command; 1264 u_int8_t reserved; 1265 u_int8_t atyp; 1266 } s5_req, s5_rsp; 1267 u_int16_t dest_port; 1268 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1269 const u_char *p; 1270 u_int have, need, i, found, nmethods, addrlen, af; 1271 int r; 1272 1273 debug2("channel %d: decode socks5", c->self); 1274 p = sshbuf_ptr(input); 1275 if (p[0] != 0x05) 1276 return -1; 1277 have = sshbuf_len(input); 1278 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1279 /* format: ver | nmethods | methods */ 1280 if (have < 2) 1281 return 0; 1282 nmethods = p[1]; 1283 if (have < nmethods + 2) 1284 return 0; 1285 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1286 for (found = 0, i = 2; i < nmethods + 2; i++) { 1287 if (p[i] == SSH_SOCKS5_NOAUTH) { 1288 found = 1; 1289 break; 1290 } 1291 } 1292 if (!found) { 1293 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1294 c->self); 1295 return -1; 1296 } 1297 if ((r = sshbuf_consume(input, nmethods + 2)) != 0) { 1298 fatal("%s: channel %d: consume: %s", __func__, 1299 c->self, ssh_err(r)); 1300 } 1301 /* version, method */ 1302 if ((r = sshbuf_put_u8(output, 0x05)) != 0 || 1303 (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) { 1304 fatal("%s: channel %d: append reply: %s", __func__, 1305 c->self, ssh_err(r)); 1306 } 1307 c->flags |= SSH_SOCKS5_AUTHDONE; 1308 debug2("channel %d: socks5 auth done", c->self); 1309 return 0; /* need more */ 1310 } 1311 debug2("channel %d: socks5 post auth", c->self); 1312 if (have < sizeof(s5_req)+1) 1313 return 0; /* need more */ 1314 memcpy(&s5_req, p, sizeof(s5_req)); 1315 if (s5_req.version != 0x05 || 1316 s5_req.command != SSH_SOCKS5_CONNECT || 1317 s5_req.reserved != 0x00) { 1318 debug2("channel %d: only socks5 connect supported", c->self); 1319 return -1; 1320 } 1321 switch (s5_req.atyp){ 1322 case SSH_SOCKS5_IPV4: 1323 addrlen = 4; 1324 af = AF_INET; 1325 break; 1326 case SSH_SOCKS5_DOMAIN: 1327 addrlen = p[sizeof(s5_req)]; 1328 af = -1; 1329 break; 1330 case SSH_SOCKS5_IPV6: 1331 addrlen = 16; 1332 af = AF_INET6; 1333 break; 1334 default: 1335 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1336 return -1; 1337 } 1338 need = sizeof(s5_req) + addrlen + 2; 1339 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1340 need++; 1341 if (have < need) 1342 return 0; 1343 if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) { 1344 fatal("%s: channel %d: consume: %s", __func__, 1345 c->self, ssh_err(r)); 1346 } 1347 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1348 /* host string length */ 1349 if ((r = sshbuf_consume(input, 1)) != 0) { 1350 fatal("%s: channel %d: consume: %s", __func__, 1351 c->self, ssh_err(r)); 1352 } 1353 } 1354 if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || 1355 (r = sshbuf_get(input, &dest_port, 2)) != 0) { 1356 debug("channel %d: parse addr/port: %s", c->self, ssh_err(r)); 1357 return -1; 1358 } 1359 dest_addr[addrlen] = '\0'; 1360 free(c->path); 1361 c->path = NULL; 1362 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1363 if (addrlen >= NI_MAXHOST) { 1364 error("channel %d: dynamic request: socks5 hostname " 1365 "\"%.100s\" too long", c->self, dest_addr); 1366 return -1; 1367 } 1368 c->path = xstrdup(dest_addr); 1369 } else { 1370 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1371 return -1; 1372 c->path = xstrdup(ntop); 1373 } 1374 c->host_port = ntohs(dest_port); 1375 1376 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1377 c->self, c->path, c->host_port, s5_req.command); 1378 1379 s5_rsp.version = 0x05; 1380 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1381 s5_rsp.reserved = 0; /* ignored */ 1382 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1383 dest_port = 0; /* ignored */ 1384 1385 if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || 1386 (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || 1387 (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) 1388 fatal("%s: channel %d: append reply: %s", __func__, 1389 c->self, ssh_err(r)); 1390 return 1; 1391 } 1392 1393 Channel * 1394 channel_connect_stdio_fwd(struct ssh *ssh, 1395 const char *host_to_connect, u_short port_to_connect, int in, int out) 1396 { 1397 Channel *c; 1398 1399 debug("%s %s:%d", __func__, host_to_connect, port_to_connect); 1400 1401 c = channel_new(ssh, "stdio-forward", SSH_CHANNEL_OPENING, in, out, 1402 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1403 0, "stdio-forward", /*nonblock*/0); 1404 1405 c->path = xstrdup(host_to_connect); 1406 c->host_port = port_to_connect; 1407 c->listening_port = 0; 1408 c->force_drain = 1; 1409 1410 channel_register_fds(ssh, c, in, out, -1, 0, 1, 0); 1411 port_open_helper(ssh, c, "direct-tcpip"); 1412 1413 return c; 1414 } 1415 1416 /* dynamic port forwarding */ 1417 static void 1418 channel_pre_dynamic(struct ssh *ssh, Channel *c, 1419 fd_set *readset, fd_set *writeset) 1420 { 1421 const u_char *p; 1422 u_int have; 1423 int ret; 1424 1425 have = sshbuf_len(c->input); 1426 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1427 /* sshbuf_dump(c->input, stderr); */ 1428 /* check if the fixed size part of the packet is in buffer. */ 1429 if (have < 3) { 1430 /* need more */ 1431 FD_SET(c->sock, readset); 1432 return; 1433 } 1434 /* try to guess the protocol */ 1435 p = sshbuf_ptr(c->input); 1436 /* XXX sshbuf_peek_u8? */ 1437 switch (p[0]) { 1438 case 0x04: 1439 ret = channel_decode_socks4(c, c->input, c->output); 1440 break; 1441 case 0x05: 1442 ret = channel_decode_socks5(c, c->input, c->output); 1443 break; 1444 default: 1445 ret = -1; 1446 break; 1447 } 1448 if (ret < 0) { 1449 chan_mark_dead(ssh, c); 1450 } else if (ret == 0) { 1451 debug2("channel %d: pre_dynamic: need more", c->self); 1452 /* need more */ 1453 FD_SET(c->sock, readset); 1454 if (sshbuf_len(c->output)) 1455 FD_SET(c->sock, writeset); 1456 } else { 1457 /* switch to the next state */ 1458 c->type = SSH_CHANNEL_OPENING; 1459 port_open_helper(ssh, c, "direct-tcpip"); 1460 } 1461 } 1462 1463 /* simulate read-error */ 1464 static void 1465 rdynamic_close(struct ssh *ssh, Channel *c) 1466 { 1467 c->type = SSH_CHANNEL_OPEN; 1468 chan_read_failed(ssh, c); 1469 sshbuf_reset(c->input); 1470 chan_ibuf_empty(ssh, c); 1471 sshbuf_reset(c->output); 1472 chan_write_failed(ssh, c); 1473 } 1474 1475 /* reverse dynamic port forwarding */ 1476 static void 1477 channel_before_prepare_select_rdynamic(struct ssh *ssh, Channel *c) 1478 { 1479 const u_char *p; 1480 u_int have, len; 1481 int r, ret; 1482 1483 have = sshbuf_len(c->output); 1484 debug2("channel %d: pre_rdynamic: have %d", c->self, have); 1485 /* sshbuf_dump(c->output, stderr); */ 1486 /* EOF received */ 1487 if (c->flags & CHAN_EOF_RCVD) { 1488 if ((r = sshbuf_consume(c->output, have)) != 0) { 1489 fatal("%s: channel %d: consume: %s", 1490 __func__, c->self, ssh_err(r)); 1491 } 1492 rdynamic_close(ssh, c); 1493 return; 1494 } 1495 /* check if the fixed size part of the packet is in buffer. */ 1496 if (have < 3) 1497 return; 1498 /* try to guess the protocol */ 1499 p = sshbuf_ptr(c->output); 1500 switch (p[0]) { 1501 case 0x04: 1502 /* switch input/output for reverse forwarding */ 1503 ret = channel_decode_socks4(c, c->output, c->input); 1504 break; 1505 case 0x05: 1506 ret = channel_decode_socks5(c, c->output, c->input); 1507 break; 1508 default: 1509 ret = -1; 1510 break; 1511 } 1512 if (ret < 0) { 1513 rdynamic_close(ssh, c); 1514 } else if (ret == 0) { 1515 debug2("channel %d: pre_rdynamic: need more", c->self); 1516 /* send socks request to peer */ 1517 len = sshbuf_len(c->input); 1518 if (len > 0 && len < c->remote_window) { 1519 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 1520 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1521 (r = sshpkt_put_stringb(ssh, c->input)) != 0 || 1522 (r = sshpkt_send(ssh)) != 0) { 1523 fatal("%s: channel %i: rdynamic: %s", __func__, 1524 c->self, ssh_err(r)); 1525 } 1526 if ((r = sshbuf_consume(c->input, len)) != 0) { 1527 fatal("%s: channel %d: consume: %s", 1528 __func__, c->self, ssh_err(r)); 1529 } 1530 c->remote_window -= len; 1531 } 1532 } else if (rdynamic_connect_finish(ssh, c) < 0) { 1533 /* the connect failed */ 1534 rdynamic_close(ssh, c); 1535 } 1536 } 1537 1538 /* This is our fake X11 server socket. */ 1539 static void 1540 channel_post_x11_listener(struct ssh *ssh, Channel *c, 1541 fd_set *readset, fd_set *writeset) 1542 { 1543 Channel *nc; 1544 struct sockaddr_storage addr; 1545 int r, newsock, oerrno, remote_port; 1546 socklen_t addrlen; 1547 char buf[16384], *remote_ipaddr; 1548 1549 if (!FD_ISSET(c->sock, readset)) 1550 return; 1551 1552 debug("X11 connection requested."); 1553 addrlen = sizeof(addr); 1554 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1555 if (c->single_connection) { 1556 oerrno = errno; 1557 debug2("single_connection: closing X11 listener."); 1558 channel_close_fd(ssh, &c->sock); 1559 chan_mark_dead(ssh, c); 1560 errno = oerrno; 1561 } 1562 if (newsock < 0) { 1563 if (errno != EINTR && errno != EWOULDBLOCK && 1564 errno != ECONNABORTED) 1565 error("accept: %.100s", strerror(errno)); 1566 if (errno == EMFILE || errno == ENFILE) 1567 c->notbefore = monotime() + 1; 1568 return; 1569 } 1570 set_nodelay(newsock); 1571 remote_ipaddr = get_peer_ipaddr(newsock); 1572 remote_port = get_peer_port(newsock); 1573 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1574 remote_ipaddr, remote_port); 1575 1576 nc = channel_new(ssh, "accepted x11 socket", 1577 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1578 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1579 open_preamble(ssh, __func__, nc, "x11"); 1580 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1581 (r = sshpkt_put_u32(ssh, remote_port)) != 0) { 1582 fatal("%s: channel %i: reply %s", __func__, 1583 c->self, ssh_err(r)); 1584 } 1585 if ((r = sshpkt_send(ssh)) != 0) 1586 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); 1587 free(remote_ipaddr); 1588 } 1589 1590 static void 1591 port_open_helper(struct ssh *ssh, Channel *c, char *rtype) 1592 { 1593 char *local_ipaddr = get_local_ipaddr(c->sock); 1594 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1595 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1596 int remote_port = get_peer_port(c->sock); 1597 int r; 1598 1599 if (remote_port == -1) { 1600 /* Fake addr/port to appease peers that validate it (Tectia) */ 1601 free(remote_ipaddr); 1602 remote_ipaddr = xstrdup("127.0.0.1"); 1603 remote_port = 65535; 1604 } 1605 1606 free(c->remote_name); 1607 xasprintf(&c->remote_name, 1608 "%s: listening port %d for %.100s port %d, " 1609 "connect from %.200s port %d to %.100s port %d", 1610 rtype, c->listening_port, c->path, c->host_port, 1611 remote_ipaddr, remote_port, local_ipaddr, local_port); 1612 1613 open_preamble(ssh, __func__, c, rtype); 1614 if (strcmp(rtype, "direct-tcpip") == 0) { 1615 /* target host, port */ 1616 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1617 (r = sshpkt_put_u32(ssh, c->host_port)) != 0) { 1618 fatal("%s: channel %i: reply %s", __func__, 1619 c->self, ssh_err(r)); 1620 } 1621 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1622 /* target path */ 1623 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { 1624 fatal("%s: channel %i: reply %s", __func__, 1625 c->self, ssh_err(r)); 1626 } 1627 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1628 /* listen path */ 1629 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { 1630 fatal("%s: channel %i: reply %s", __func__, 1631 c->self, ssh_err(r)); 1632 } 1633 } else { 1634 /* listen address, port */ 1635 if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || 1636 (r = sshpkt_put_u32(ssh, local_port)) != 0) { 1637 fatal("%s: channel %i: reply %s", __func__, 1638 c->self, ssh_err(r)); 1639 } 1640 } 1641 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1642 /* reserved for future owner/mode info */ 1643 if ((r = sshpkt_put_cstring(ssh, "")) != 0) { 1644 fatal("%s: channel %i: reply %s", __func__, 1645 c->self, ssh_err(r)); 1646 } 1647 } else { 1648 /* originator host and port */ 1649 if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || 1650 (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) { 1651 fatal("%s: channel %i: reply %s", __func__, 1652 c->self, ssh_err(r)); 1653 } 1654 } 1655 if ((r = sshpkt_send(ssh)) != 0) 1656 fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); 1657 free(remote_ipaddr); 1658 free(local_ipaddr); 1659 } 1660 1661 void 1662 channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time) 1663 { 1664 ssh->chanctxt->x11_refuse_time = refuse_time; 1665 } 1666 1667 /* 1668 * This socket is listening for connections to a forwarded TCP/IP port. 1669 */ 1670 static void 1671 channel_post_port_listener(struct ssh *ssh, Channel *c, 1672 fd_set *readset, fd_set *writeset) 1673 { 1674 Channel *nc; 1675 struct sockaddr_storage addr; 1676 int newsock, nextstate; 1677 socklen_t addrlen; 1678 char *rtype; 1679 1680 if (!FD_ISSET(c->sock, readset)) 1681 return; 1682 1683 debug("Connection to port %d forwarding to %.100s port %d requested.", 1684 c->listening_port, c->path, c->host_port); 1685 1686 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1687 nextstate = SSH_CHANNEL_OPENING; 1688 rtype = "forwarded-tcpip"; 1689 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1690 nextstate = SSH_CHANNEL_OPENING; 1691 rtype = "forwarded-streamlocal@openssh.com"; 1692 } else if (c->host_port == PORT_STREAMLOCAL) { 1693 nextstate = SSH_CHANNEL_OPENING; 1694 rtype = "direct-streamlocal@openssh.com"; 1695 } else if (c->host_port == 0) { 1696 nextstate = SSH_CHANNEL_DYNAMIC; 1697 rtype = "dynamic-tcpip"; 1698 } else { 1699 nextstate = SSH_CHANNEL_OPENING; 1700 rtype = "direct-tcpip"; 1701 } 1702 1703 addrlen = sizeof(addr); 1704 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1705 if (newsock < 0) { 1706 if (errno != EINTR && errno != EWOULDBLOCK && 1707 errno != ECONNABORTED) 1708 error("accept: %.100s", strerror(errno)); 1709 if (errno == EMFILE || errno == ENFILE) 1710 c->notbefore = monotime() + 1; 1711 return; 1712 } 1713 if (c->host_port != PORT_STREAMLOCAL) 1714 set_nodelay(newsock); 1715 nc = channel_new(ssh, rtype, nextstate, newsock, newsock, -1, 1716 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1717 nc->listening_port = c->listening_port; 1718 nc->host_port = c->host_port; 1719 if (c->path != NULL) 1720 nc->path = xstrdup(c->path); 1721 1722 if (nextstate != SSH_CHANNEL_DYNAMIC) 1723 port_open_helper(ssh, nc, rtype); 1724 } 1725 1726 /* 1727 * This is the authentication agent socket listening for connections from 1728 * clients. 1729 */ 1730 static void 1731 channel_post_auth_listener(struct ssh *ssh, Channel *c, 1732 fd_set *readset, fd_set *writeset) 1733 { 1734 Channel *nc; 1735 int r, newsock; 1736 struct sockaddr_storage addr; 1737 socklen_t addrlen; 1738 1739 if (!FD_ISSET(c->sock, readset)) 1740 return; 1741 1742 addrlen = sizeof(addr); 1743 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1744 if (newsock < 0) { 1745 error("accept from auth socket: %.100s", strerror(errno)); 1746 if (errno == EMFILE || errno == ENFILE) 1747 c->notbefore = monotime() + 1; 1748 return; 1749 } 1750 nc = channel_new(ssh, "accepted auth socket", 1751 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1752 c->local_window_max, c->local_maxpacket, 1753 0, "accepted auth socket", 1); 1754 open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); 1755 if ((r = sshpkt_send(ssh)) != 0) 1756 fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); 1757 } 1758 1759 static void 1760 channel_post_connecting(struct ssh *ssh, Channel *c, 1761 fd_set *readset, fd_set *writeset) 1762 { 1763 int err = 0, sock, isopen, r; 1764 socklen_t sz = sizeof(err); 1765 1766 if (!FD_ISSET(c->sock, writeset)) 1767 return; 1768 if (!c->have_remote_id) 1769 fatal(":%s: channel %d: no remote id", __func__, c->self); 1770 /* for rdynamic the OPEN_CONFIRMATION has been sent already */ 1771 isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); 1772 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { 1773 err = errno; 1774 error("getsockopt SO_ERROR failed"); 1775 } 1776 if (err == 0) { 1777 debug("channel %d: connected to %s port %d", 1778 c->self, c->connect_ctx.host, c->connect_ctx.port); 1779 channel_connect_ctx_free(&c->connect_ctx); 1780 c->type = SSH_CHANNEL_OPEN; 1781 if (isopen) { 1782 /* no message necessary */ 1783 } else { 1784 if ((r = sshpkt_start(ssh, 1785 SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1786 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1787 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1788 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1789 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) 1790 != 0) 1791 fatal("%s: channel %i: confirm: %s", __func__, 1792 c->self, ssh_err(r)); 1793 if ((r = sshpkt_send(ssh)) != 0) 1794 fatal("%s: channel %i: %s", __func__, c->self, 1795 ssh_err(r)); 1796 } 1797 } else { 1798 debug("channel %d: connection failed: %s", 1799 c->self, strerror(err)); 1800 /* Try next address, if any */ 1801 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1802 close(c->sock); 1803 c->sock = c->rfd = c->wfd = sock; 1804 channel_find_maxfd(ssh->chanctxt); 1805 return; 1806 } 1807 /* Exhausted all addresses */ 1808 error("connect_to %.100s port %d: failed.", 1809 c->connect_ctx.host, c->connect_ctx.port); 1810 channel_connect_ctx_free(&c->connect_ctx); 1811 if (isopen) { 1812 rdynamic_close(ssh, c); 1813 } else { 1814 if ((r = sshpkt_start(ssh, 1815 SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1816 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1817 (r = sshpkt_put_u32(ssh, 1818 SSH2_OPEN_CONNECT_FAILED)) != 0 || 1819 (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || 1820 (r = sshpkt_put_cstring(ssh, "")) != 0) { 1821 fatal("%s: channel %i: failure: %s", __func__, 1822 c->self, ssh_err(r)); 1823 } 1824 if ((r = sshpkt_send(ssh)) != 0) 1825 fatal("%s: channel %i: %s", __func__, c->self, 1826 ssh_err(r)); 1827 chan_mark_dead(ssh, c); 1828 } 1829 } 1830 } 1831 1832 static int 1833 channel_handle_rfd(struct ssh *ssh, Channel *c, 1834 fd_set *readset, fd_set *writeset) 1835 { 1836 char buf[CHAN_RBUF]; 1837 ssize_t len; 1838 int r; 1839 1840 if (c->rfd == -1 || !FD_ISSET(c->rfd, readset)) 1841 return 1; 1842 1843 len = read(c->rfd, buf, sizeof(buf)); 1844 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1845 return 1; 1846 if (len <= 0) { 1847 debug2("channel %d: read<=0 rfd %d len %zd", 1848 c->self, c->rfd, len); 1849 if (c->type != SSH_CHANNEL_OPEN) { 1850 debug2("channel %d: not open", c->self); 1851 chan_mark_dead(ssh, c); 1852 return -1; 1853 } else { 1854 chan_read_failed(ssh, c); 1855 } 1856 return -1; 1857 } 1858 if (c->input_filter != NULL) { 1859 if (c->input_filter(ssh, c, buf, len) == -1) { 1860 debug2("channel %d: filter stops", c->self); 1861 chan_read_failed(ssh, c); 1862 } 1863 } else if (c->datagram) { 1864 if ((r = sshbuf_put_string(c->input, buf, len)) != 0) 1865 fatal("%s: channel %d: put datagram: %s", __func__, 1866 c->self, ssh_err(r)); 1867 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { 1868 fatal("%s: channel %d: put data: %s", __func__, 1869 c->self, ssh_err(r)); 1870 } 1871 return 1; 1872 } 1873 1874 static int 1875 channel_handle_wfd(struct ssh *ssh, Channel *c, 1876 fd_set *readset, fd_set *writeset) 1877 { 1878 struct termios tio; 1879 u_char *data = NULL, *buf; /* XXX const; need filter API change */ 1880 size_t dlen, olen = 0; 1881 int r, len; 1882 1883 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || 1884 sshbuf_len(c->output) == 0) 1885 return 1; 1886 1887 /* Send buffered output data to the socket. */ 1888 olen = sshbuf_len(c->output); 1889 if (c->output_filter != NULL) { 1890 if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { 1891 debug2("channel %d: filter stops", c->self); 1892 if (c->type != SSH_CHANNEL_OPEN) 1893 chan_mark_dead(ssh, c); 1894 else 1895 chan_write_failed(ssh, c); 1896 return -1; 1897 } 1898 } else if (c->datagram) { 1899 if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) 1900 fatal("%s: channel %d: get datagram: %s", __func__, 1901 c->self, ssh_err(r)); 1902 buf = data; 1903 } else { 1904 buf = data = sshbuf_mutable_ptr(c->output); 1905 dlen = sshbuf_len(c->output); 1906 } 1907 1908 if (c->datagram) { 1909 /* ignore truncated writes, datagrams might get lost */ 1910 len = write(c->wfd, buf, dlen); 1911 free(data); 1912 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1913 return 1; 1914 if (len <= 0) 1915 goto write_fail; 1916 goto out; 1917 } 1918 1919 len = write(c->wfd, buf, dlen); 1920 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1921 return 1; 1922 if (len <= 0) { 1923 write_fail: 1924 if (c->type != SSH_CHANNEL_OPEN) { 1925 debug2("channel %d: not open", c->self); 1926 chan_mark_dead(ssh, c); 1927 return -1; 1928 } else { 1929 chan_write_failed(ssh, c); 1930 } 1931 return -1; 1932 } 1933 if (c->isatty && dlen >= 1 && buf[0] != '\r') { 1934 if (tcgetattr(c->wfd, &tio) == 0 && 1935 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 1936 /* 1937 * Simulate echo to reduce the impact of 1938 * traffic analysis. We need to match the 1939 * size of a SSH2_MSG_CHANNEL_DATA message 1940 * (4 byte channel id + buf) 1941 */ 1942 if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || 1943 (r = sshpkt_send(ssh)) != 0) 1944 fatal("%s: channel %d: ignore: %s", 1945 __func__, c->self, ssh_err(r)); 1946 } 1947 } 1948 if ((r = sshbuf_consume(c->output, len)) != 0) { 1949 fatal("%s: channel %d: consume: %s", 1950 __func__, c->self, ssh_err(r)); 1951 } 1952 out: 1953 c->local_consumed += olen - sshbuf_len(c->output); 1954 1955 return 1; 1956 } 1957 1958 static int 1959 channel_handle_efd_write(struct ssh *ssh, Channel *c, 1960 fd_set *readset, fd_set *writeset) 1961 { 1962 int r; 1963 ssize_t len; 1964 1965 if (!FD_ISSET(c->efd, writeset) || sshbuf_len(c->extended) == 0) 1966 return 1; 1967 1968 len = write(c->efd, sshbuf_ptr(c->extended), 1969 sshbuf_len(c->extended)); 1970 debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); 1971 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1972 return 1; 1973 if (len <= 0) { 1974 debug2("channel %d: closing write-efd %d", c->self, c->efd); 1975 channel_close_fd(ssh, &c->efd); 1976 } else { 1977 if ((r = sshbuf_consume(c->extended, len)) != 0) { 1978 fatal("%s: channel %d: consume: %s", 1979 __func__, c->self, ssh_err(r)); 1980 } 1981 c->local_consumed += len; 1982 } 1983 return 1; 1984 } 1985 1986 static int 1987 channel_handle_efd_read(struct ssh *ssh, Channel *c, 1988 fd_set *readset, fd_set *writeset) 1989 { 1990 char buf[CHAN_RBUF]; 1991 int r; 1992 ssize_t len; 1993 1994 if (!FD_ISSET(c->efd, readset)) 1995 return 1; 1996 1997 len = read(c->efd, buf, sizeof(buf)); 1998 debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); 1999 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 2000 return 1; 2001 if (len <= 0) { 2002 debug2("channel %d: closing read-efd %d", 2003 c->self, c->efd); 2004 channel_close_fd(ssh, &c->efd); 2005 } else { 2006 if (c->extended_usage == CHAN_EXTENDED_IGNORE) { 2007 debug3("channel %d: discard efd", 2008 c->self); 2009 } else if ((r = sshbuf_put(c->extended, buf, len)) != 0) { 2010 fatal("%s: channel %d: append: %s", 2011 __func__, c->self, ssh_err(r)); 2012 } 2013 } 2014 return 1; 2015 } 2016 2017 static int 2018 channel_handle_efd(struct ssh *ssh, Channel *c, 2019 fd_set *readset, fd_set *writeset) 2020 { 2021 if (c->efd == -1) 2022 return 1; 2023 2024 /** XXX handle drain efd, too */ 2025 2026 if (c->extended_usage == CHAN_EXTENDED_WRITE) 2027 return channel_handle_efd_write(ssh, c, readset, writeset); 2028 else if (c->extended_usage == CHAN_EXTENDED_READ || 2029 c->extended_usage == CHAN_EXTENDED_IGNORE) 2030 return channel_handle_efd_read(ssh, c, readset, writeset); 2031 2032 return 1; 2033 } 2034 2035 static int 2036 channel_check_window(struct ssh *ssh, Channel *c) 2037 { 2038 int r; 2039 2040 if (c->type == SSH_CHANNEL_OPEN && 2041 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 2042 ((c->local_window_max - c->local_window > 2043 c->local_maxpacket*3) || 2044 c->local_window < c->local_window_max/2) && 2045 c->local_consumed > 0) { 2046 if (!c->have_remote_id) 2047 fatal(":%s: channel %d: no remote id", 2048 __func__, c->self); 2049 if ((r = sshpkt_start(ssh, 2050 SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || 2051 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2052 (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || 2053 (r = sshpkt_send(ssh)) != 0) { 2054 fatal("%s: channel %i: %s", __func__, 2055 c->self, ssh_err(r)); 2056 } 2057 debug2("channel %d: window %d sent adjust %d", 2058 c->self, c->local_window, 2059 c->local_consumed); 2060 c->local_window += c->local_consumed; 2061 c->local_consumed = 0; 2062 } 2063 return 1; 2064 } 2065 2066 static void 2067 channel_post_open(struct ssh *ssh, Channel *c, 2068 fd_set *readset, fd_set *writeset) 2069 { 2070 channel_handle_rfd(ssh, c, readset, writeset); 2071 channel_handle_wfd(ssh, c, readset, writeset); 2072 channel_handle_efd(ssh, c, readset, writeset); 2073 channel_check_window(ssh, c); 2074 } 2075 2076 static u_int 2077 read_mux(struct ssh *ssh, Channel *c, u_int need) 2078 { 2079 char buf[CHAN_RBUF]; 2080 ssize_t len; 2081 u_int rlen; 2082 int r; 2083 2084 if (sshbuf_len(c->input) < need) { 2085 rlen = need - sshbuf_len(c->input); 2086 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 2087 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 2088 return sshbuf_len(c->input); 2089 if (len <= 0) { 2090 debug2("channel %d: ctl read<=0 rfd %d len %zd", 2091 c->self, c->rfd, len); 2092 chan_read_failed(ssh, c); 2093 return 0; 2094 } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { 2095 fatal("%s: channel %d: append: %s", 2096 __func__, c->self, ssh_err(r)); 2097 } 2098 } 2099 return sshbuf_len(c->input); 2100 } 2101 2102 static void 2103 channel_post_mux_client_read(struct ssh *ssh, Channel *c, 2104 fd_set *readset, fd_set *writeset) 2105 { 2106 u_int need; 2107 2108 if (c->rfd == -1 || !FD_ISSET(c->rfd, readset)) 2109 return; 2110 if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) 2111 return; 2112 if (c->mux_pause) 2113 return; 2114 2115 /* 2116 * Don't not read past the precise end of packets to 2117 * avoid disrupting fd passing. 2118 */ 2119 if (read_mux(ssh, c, 4) < 4) /* read header */ 2120 return; 2121 /* XXX sshbuf_peek_u32 */ 2122 need = PEEK_U32(sshbuf_ptr(c->input)); 2123 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 2124 if (need > CHANNEL_MUX_MAX_PACKET) { 2125 debug2("channel %d: packet too big %u > %u", 2126 c->self, CHANNEL_MUX_MAX_PACKET, need); 2127 chan_rcvd_oclose(ssh, c); 2128 return; 2129 } 2130 if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ 2131 return; 2132 if (c->mux_rcb(ssh, c) != 0) { 2133 debug("channel %d: mux_rcb failed", c->self); 2134 chan_mark_dead(ssh, c); 2135 return; 2136 } 2137 } 2138 2139 static void 2140 channel_post_mux_client_write(struct ssh *ssh, Channel *c, 2141 fd_set *readset, fd_set *writeset) 2142 { 2143 ssize_t len; 2144 int r; 2145 2146 if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || 2147 sshbuf_len(c->output) == 0) 2148 return; 2149 2150 len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); 2151 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 2152 return; 2153 if (len <= 0) { 2154 chan_mark_dead(ssh, c); 2155 return; 2156 } 2157 if ((r = sshbuf_consume(c->output, len)) != 0) 2158 fatal("%s: channel %d: consume: %s", __func__, 2159 c->self, ssh_err(r)); 2160 } 2161 2162 static void 2163 channel_post_mux_client(struct ssh *ssh, Channel *c, 2164 fd_set *readset, fd_set *writeset) 2165 { 2166 channel_post_mux_client_read(ssh, c, readset, writeset); 2167 channel_post_mux_client_write(ssh, c, readset, writeset); 2168 } 2169 2170 static void 2171 channel_post_mux_listener(struct ssh *ssh, Channel *c, 2172 fd_set *readset, fd_set *writeset) 2173 { 2174 Channel *nc; 2175 struct sockaddr_storage addr; 2176 socklen_t addrlen; 2177 int newsock; 2178 uid_t euid; 2179 gid_t egid; 2180 2181 if (!FD_ISSET(c->sock, readset)) 2182 return; 2183 2184 debug("multiplexing control connection"); 2185 2186 /* 2187 * Accept connection on control socket 2188 */ 2189 memset(&addr, 0, sizeof(addr)); 2190 addrlen = sizeof(addr); 2191 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 2192 &addrlen)) == -1) { 2193 error("%s accept: %s", __func__, strerror(errno)); 2194 if (errno == EMFILE || errno == ENFILE) 2195 c->notbefore = monotime() + 1; 2196 return; 2197 } 2198 2199 if (getpeereid(newsock, &euid, &egid) < 0) { 2200 error("%s getpeereid failed: %s", __func__, 2201 strerror(errno)); 2202 close(newsock); 2203 return; 2204 } 2205 if ((euid != 0) && (getuid() != euid)) { 2206 error("multiplex uid mismatch: peer euid %u != uid %u", 2207 (u_int)euid, (u_int)getuid()); 2208 close(newsock); 2209 return; 2210 } 2211 nc = channel_new(ssh, "multiplex client", SSH_CHANNEL_MUX_CLIENT, 2212 newsock, newsock, -1, c->local_window_max, 2213 c->local_maxpacket, 0, "mux-control", 1); 2214 nc->mux_rcb = c->mux_rcb; 2215 debug3("%s: new mux channel %d fd %d", __func__, nc->self, nc->sock); 2216 /* establish state */ 2217 nc->mux_rcb(ssh, nc); 2218 /* mux state transitions must not elicit protocol messages */ 2219 nc->flags |= CHAN_LOCAL; 2220 } 2221 2222 static void 2223 channel_handler_init(struct ssh_channels *sc) 2224 { 2225 chan_fn **pre, **post; 2226 2227 if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || 2228 (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) 2229 fatal("%s: allocation failed", __func__); 2230 2231 pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2232 pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2233 pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2234 pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2235 pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2236 pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2237 pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2238 pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2239 pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2240 pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2241 pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; 2242 pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2243 pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2244 2245 post[SSH_CHANNEL_OPEN] = &channel_post_open; 2246 post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2247 post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2248 post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2249 post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2250 post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2251 post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2252 post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2253 post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2254 post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; 2255 post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2256 post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2257 2258 sc->channel_pre = pre; 2259 sc->channel_post = post; 2260 } 2261 2262 /* gc dead channels */ 2263 static void 2264 channel_garbage_collect(struct ssh *ssh, Channel *c) 2265 { 2266 if (c == NULL) 2267 return; 2268 if (c->detach_user != NULL) { 2269 if (!chan_is_dead(ssh, c, c->detach_close)) 2270 return; 2271 debug2("channel %d: gc: notify user", c->self); 2272 c->detach_user(ssh, c->self, NULL); 2273 /* if we still have a callback */ 2274 if (c->detach_user != NULL) 2275 return; 2276 debug2("channel %d: gc: user detached", c->self); 2277 } 2278 if (!chan_is_dead(ssh, c, 1)) 2279 return; 2280 debug2("channel %d: garbage collecting", c->self); 2281 channel_free(ssh, c); 2282 } 2283 2284 enum channel_table { CHAN_PRE, CHAN_POST }; 2285 2286 static void 2287 channel_handler(struct ssh *ssh, int table, 2288 fd_set *readset, fd_set *writeset, time_t *unpause_secs) 2289 { 2290 struct ssh_channels *sc = ssh->chanctxt; 2291 chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; 2292 u_int i, oalloc; 2293 Channel *c; 2294 time_t now; 2295 2296 now = monotime(); 2297 if (unpause_secs != NULL) 2298 *unpause_secs = 0; 2299 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2300 c = sc->channels[i]; 2301 if (c == NULL) 2302 continue; 2303 if (c->delayed) { 2304 if (table == CHAN_PRE) 2305 c->delayed = 0; 2306 else 2307 continue; 2308 } 2309 if (ftab[c->type] != NULL) { 2310 /* 2311 * Run handlers that are not paused. 2312 */ 2313 if (c->notbefore <= now) 2314 (*ftab[c->type])(ssh, c, readset, writeset); 2315 else if (unpause_secs != NULL) { 2316 /* 2317 * Collect the time that the earliest 2318 * channel comes off pause. 2319 */ 2320 debug3("%s: chan %d: skip for %d more seconds", 2321 __func__, c->self, 2322 (int)(c->notbefore - now)); 2323 if (*unpause_secs == 0 || 2324 (c->notbefore - now) < *unpause_secs) 2325 *unpause_secs = c->notbefore - now; 2326 } 2327 } 2328 channel_garbage_collect(ssh, c); 2329 } 2330 if (unpause_secs != NULL && *unpause_secs != 0) 2331 debug3("%s: first channel unpauses in %d seconds", 2332 __func__, (int)*unpause_secs); 2333 } 2334 2335 /* 2336 * Create sockets before allocating the select bitmasks. 2337 * This is necessary for things that need to happen after reading 2338 * the network-input but before channel_prepare_select(). 2339 */ 2340 static void 2341 channel_before_prepare_select(struct ssh *ssh) 2342 { 2343 struct ssh_channels *sc = ssh->chanctxt; 2344 Channel *c; 2345 u_int i, oalloc; 2346 2347 for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { 2348 c = sc->channels[i]; 2349 if (c == NULL) 2350 continue; 2351 if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) 2352 channel_before_prepare_select_rdynamic(ssh, c); 2353 } 2354 } 2355 2356 /* 2357 * Allocate/update select bitmasks and add any bits relevant to channels in 2358 * select bitmasks. 2359 */ 2360 void 2361 channel_prepare_select(struct ssh *ssh, fd_set **readsetp, fd_set **writesetp, 2362 int *maxfdp, u_int *nallocp, time_t *minwait_secs) 2363 { 2364 u_int n, sz, nfdset; 2365 2366 channel_before_prepare_select(ssh); /* might update channel_max_fd */ 2367 2368 n = MAXIMUM(*maxfdp, ssh->chanctxt->channel_max_fd); 2369 2370 nfdset = howmany(n+1, NFDBITS); 2371 /* Explicitly test here, because xrealloc isn't always called */ 2372 if (nfdset && SIZE_MAX / nfdset < sizeof(fd_mask)) 2373 fatal("channel_prepare_select: max_fd (%d) is too large", n); 2374 sz = nfdset * sizeof(fd_mask); 2375 2376 /* perhaps check sz < nalloc/2 and shrink? */ 2377 if (*readsetp == NULL || sz > *nallocp) { 2378 *readsetp = xreallocarray(*readsetp, nfdset, sizeof(fd_mask)); 2379 *writesetp = xreallocarray(*writesetp, nfdset, sizeof(fd_mask)); 2380 *nallocp = sz; 2381 } 2382 *maxfdp = n; 2383 memset(*readsetp, 0, sz); 2384 memset(*writesetp, 0, sz); 2385 2386 if (!ssh_packet_is_rekeying(ssh)) 2387 channel_handler(ssh, CHAN_PRE, *readsetp, *writesetp, 2388 minwait_secs); 2389 } 2390 2391 /* 2392 * After select, perform any appropriate operations for channels which have 2393 * events pending. 2394 */ 2395 void 2396 channel_after_select(struct ssh *ssh, fd_set *readset, fd_set *writeset) 2397 { 2398 channel_handler(ssh, CHAN_POST, readset, writeset, NULL); 2399 } 2400 2401 /* 2402 * Enqueue data for channels with open or draining c->input. 2403 */ 2404 static void 2405 channel_output_poll_input_open(struct ssh *ssh, Channel *c) 2406 { 2407 size_t len, plen; 2408 const u_char *pkt; 2409 int r; 2410 2411 if ((len = sshbuf_len(c->input)) == 0) { 2412 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2413 /* 2414 * input-buffer is empty and read-socket shutdown: 2415 * tell peer, that we will not send more data: 2416 * send IEOF. 2417 * hack for extended data: delay EOF if EFD still 2418 * in use. 2419 */ 2420 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2421 debug2("channel %d: " 2422 "ibuf_empty delayed efd %d/(%zu)", 2423 c->self, c->efd, sshbuf_len(c->extended)); 2424 else 2425 chan_ibuf_empty(ssh, c); 2426 } 2427 return; 2428 } 2429 2430 if (!c->have_remote_id) 2431 fatal(":%s: channel %d: no remote id", __func__, c->self); 2432 2433 if (c->datagram) { 2434 /* Check datagram will fit; drop if not */ 2435 if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) 2436 fatal("%s: channel %d: get datagram: %s", __func__, 2437 c->self, ssh_err(r)); 2438 /* 2439 * XXX this does tail-drop on the datagram queue which is 2440 * usually suboptimal compared to head-drop. Better to have 2441 * backpressure at read time? (i.e. read + discard) 2442 */ 2443 if (plen > c->remote_window || plen > c->remote_maxpacket) { 2444 debug("channel %d: datagram too big", c->self); 2445 return; 2446 } 2447 /* Enqueue it */ 2448 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2449 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2450 (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || 2451 (r = sshpkt_send(ssh)) != 0) { 2452 fatal("%s: channel %i: datagram: %s", __func__, 2453 c->self, ssh_err(r)); 2454 } 2455 c->remote_window -= plen; 2456 return; 2457 } 2458 2459 /* Enqueue packet for buffered data. */ 2460 if (len > c->remote_window) 2461 len = c->remote_window; 2462 if (len > c->remote_maxpacket) 2463 len = c->remote_maxpacket; 2464 if (len == 0) 2465 return; 2466 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || 2467 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2468 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || 2469 (r = sshpkt_send(ssh)) != 0) { 2470 fatal("%s: channel %i: data: %s", __func__, 2471 c->self, ssh_err(r)); 2472 } 2473 if ((r = sshbuf_consume(c->input, len)) != 0) 2474 fatal("%s: channel %i: consume: %s", __func__, 2475 c->self, ssh_err(r)); 2476 c->remote_window -= len; 2477 } 2478 2479 /* 2480 * Enqueue data for channels with open c->extended in read mode. 2481 */ 2482 static void 2483 channel_output_poll_extended_read(struct ssh *ssh, Channel *c) 2484 { 2485 size_t len; 2486 int r; 2487 2488 if ((len = sshbuf_len(c->extended)) == 0) 2489 return; 2490 2491 debug2("channel %d: rwin %u elen %zu euse %d", c->self, 2492 c->remote_window, sshbuf_len(c->extended), c->extended_usage); 2493 if (len > c->remote_window) 2494 len = c->remote_window; 2495 if (len > c->remote_maxpacket) 2496 len = c->remote_maxpacket; 2497 if (len == 0) 2498 return; 2499 if (!c->have_remote_id) 2500 fatal(":%s: channel %d: no remote id", __func__, c->self); 2501 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || 2502 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 2503 (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || 2504 (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || 2505 (r = sshpkt_send(ssh)) != 0) { 2506 fatal("%s: channel %i: data: %s", __func__, 2507 c->self, ssh_err(r)); 2508 } 2509 if ((r = sshbuf_consume(c->extended, len)) != 0) 2510 fatal("%s: channel %i: consume: %s", __func__, 2511 c->self, ssh_err(r)); 2512 c->remote_window -= len; 2513 debug2("channel %d: sent ext data %zu", c->self, len); 2514 } 2515 2516 /* If there is data to send to the connection, enqueue some of it now. */ 2517 void 2518 channel_output_poll(struct ssh *ssh) 2519 { 2520 struct ssh_channels *sc = ssh->chanctxt; 2521 Channel *c; 2522 u_int i; 2523 2524 for (i = 0; i < sc->channels_alloc; i++) { 2525 c = sc->channels[i]; 2526 if (c == NULL) 2527 continue; 2528 2529 /* 2530 * We are only interested in channels that can have buffered 2531 * incoming data. 2532 */ 2533 if (c->type != SSH_CHANNEL_OPEN) 2534 continue; 2535 if ((c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2536 /* XXX is this true? */ 2537 debug3("channel %d: will not send data after close", 2538 c->self); 2539 continue; 2540 } 2541 2542 /* Get the amount of buffered data for this channel. */ 2543 if (c->istate == CHAN_INPUT_OPEN || 2544 c->istate == CHAN_INPUT_WAIT_DRAIN) 2545 channel_output_poll_input_open(ssh, c); 2546 /* Send extended data, i.e. stderr */ 2547 if (!(c->flags & CHAN_EOF_SENT) && 2548 c->extended_usage == CHAN_EXTENDED_READ) 2549 channel_output_poll_extended_read(ssh, c); 2550 } 2551 } 2552 2553 /* -- mux proxy support */ 2554 2555 /* 2556 * When multiplexing channel messages for mux clients we have to deal 2557 * with downstream messages from the mux client and upstream messages 2558 * from the ssh server: 2559 * 1) Handling downstream messages is straightforward and happens 2560 * in channel_proxy_downstream(): 2561 * - We forward all messages (mostly) unmodified to the server. 2562 * - However, in order to route messages from upstream to the correct 2563 * downstream client, we have to replace the channel IDs used by the 2564 * mux clients with a unique channel ID because the mux clients might 2565 * use conflicting channel IDs. 2566 * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and 2567 * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local 2568 * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID 2569 * with the newly allocated channel ID. 2570 * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY 2571 * channels and processed by channel_proxy_upstream(). The local channel ID 2572 * is then translated back to the original mux client ID. 2573 * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE 2574 * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. 2575 * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the 2576 * downstream mux client are removed. 2577 * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server 2578 * requires more work, because they are not addressed to a specific 2579 * channel. E.g. client_request_forwarded_tcpip() needs to figure 2580 * out whether the request is addressed to the local client or a 2581 * specific downstream client based on the listen-address/port. 2582 * 6) Agent and X11-Forwarding have a similar problem and are currently 2583 * not supported as the matching session/channel cannot be identified 2584 * easily. 2585 */ 2586 2587 /* 2588 * receive packets from downstream mux clients: 2589 * channel callback fired on read from mux client, creates 2590 * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs 2591 * on channel creation. 2592 */ 2593 int 2594 channel_proxy_downstream(struct ssh *ssh, Channel *downstream) 2595 { 2596 Channel *c = NULL; 2597 struct sshbuf *original = NULL, *modified = NULL; 2598 const u_char *cp; 2599 char *ctype = NULL, *listen_host = NULL; 2600 u_char type; 2601 size_t have; 2602 int ret = -1, r; 2603 u_int id, remote_id, listen_port; 2604 2605 /* sshbuf_dump(downstream->input, stderr); */ 2606 if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) 2607 != 0) { 2608 error("%s: malformed message: %s", __func__, ssh_err(r)); 2609 return -1; 2610 } 2611 if (have < 2) { 2612 error("%s: short message", __func__); 2613 return -1; 2614 } 2615 type = cp[1]; 2616 /* skip padlen + type */ 2617 cp += 2; 2618 have -= 2; 2619 if (ssh_packet_log_type(type)) 2620 debug3("%s: channel %u: down->up: type %u", __func__, 2621 downstream->self, type); 2622 2623 switch (type) { 2624 case SSH2_MSG_CHANNEL_OPEN: 2625 if ((original = sshbuf_from(cp, have)) == NULL || 2626 (modified = sshbuf_new()) == NULL) { 2627 error("%s: alloc", __func__); 2628 goto out; 2629 } 2630 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || 2631 (r = sshbuf_get_u32(original, &id)) != 0) { 2632 error("%s: parse error %s", __func__, ssh_err(r)); 2633 goto out; 2634 } 2635 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2636 -1, -1, -1, 0, 0, 0, ctype, 1); 2637 c->mux_ctx = downstream; /* point to mux client */ 2638 c->mux_downstream_id = id; /* original downstream id */ 2639 if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || 2640 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2641 (r = sshbuf_putb(modified, original)) != 0) { 2642 error("%s: compose error %s", __func__, ssh_err(r)); 2643 channel_free(ssh, c); 2644 goto out; 2645 } 2646 break; 2647 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2648 /* 2649 * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we 2650 * need to parse 'remote_id' instead of 'ctype'. 2651 */ 2652 if ((original = sshbuf_from(cp, have)) == NULL || 2653 (modified = sshbuf_new()) == NULL) { 2654 error("%s: alloc", __func__); 2655 goto out; 2656 } 2657 if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || 2658 (r = sshbuf_get_u32(original, &id)) != 0) { 2659 error("%s: parse error %s", __func__, ssh_err(r)); 2660 goto out; 2661 } 2662 c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, 2663 -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); 2664 c->mux_ctx = downstream; /* point to mux client */ 2665 c->mux_downstream_id = id; 2666 c->remote_id = remote_id; 2667 c->have_remote_id = 1; 2668 if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || 2669 (r = sshbuf_put_u32(modified, c->self)) != 0 || 2670 (r = sshbuf_putb(modified, original)) != 0) { 2671 error("%s: compose error %s", __func__, ssh_err(r)); 2672 channel_free(ssh, c); 2673 goto out; 2674 } 2675 break; 2676 case SSH2_MSG_GLOBAL_REQUEST: 2677 if ((original = sshbuf_from(cp, have)) == NULL) { 2678 error("%s: alloc", __func__); 2679 goto out; 2680 } 2681 if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { 2682 error("%s: parse error %s", __func__, ssh_err(r)); 2683 goto out; 2684 } 2685 if (strcmp(ctype, "tcpip-forward") != 0) { 2686 error("%s: unsupported request %s", __func__, ctype); 2687 goto out; 2688 } 2689 if ((r = sshbuf_get_u8(original, NULL)) != 0 || 2690 (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || 2691 (r = sshbuf_get_u32(original, &listen_port)) != 0) { 2692 error("%s: parse error %s", __func__, ssh_err(r)); 2693 goto out; 2694 } 2695 if (listen_port > 65535) { 2696 error("%s: tcpip-forward for %s: bad port %u", 2697 __func__, listen_host, listen_port); 2698 goto out; 2699 } 2700 /* Record that connection to this host/port is permitted. */ 2701 fwd_perm_list_add(ssh, FWDPERM_USER, "<mux>", -1, 2702 listen_host, NULL, (int)listen_port, downstream); 2703 listen_host = NULL; 2704 break; 2705 case SSH2_MSG_CHANNEL_CLOSE: 2706 if (have < 4) 2707 break; 2708 remote_id = PEEK_U32(cp); 2709 if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { 2710 if (c->flags & CHAN_CLOSE_RCVD) 2711 channel_free(ssh, c); 2712 else 2713 c->flags |= CHAN_CLOSE_SENT; 2714 } 2715 break; 2716 } 2717 if (modified) { 2718 if ((r = sshpkt_start(ssh, type)) != 0 || 2719 (r = sshpkt_putb(ssh, modified)) != 0 || 2720 (r = sshpkt_send(ssh)) != 0) { 2721 error("%s: send %s", __func__, ssh_err(r)); 2722 goto out; 2723 } 2724 } else { 2725 if ((r = sshpkt_start(ssh, type)) != 0 || 2726 (r = sshpkt_put(ssh, cp, have)) != 0 || 2727 (r = sshpkt_send(ssh)) != 0) { 2728 error("%s: send %s", __func__, ssh_err(r)); 2729 goto out; 2730 } 2731 } 2732 ret = 0; 2733 out: 2734 free(ctype); 2735 free(listen_host); 2736 sshbuf_free(original); 2737 sshbuf_free(modified); 2738 return ret; 2739 } 2740 2741 /* 2742 * receive packets from upstream server and de-multiplex packets 2743 * to correct downstream: 2744 * implemented as a helper for channel input handlers, 2745 * replaces local (proxy) channel ID with downstream channel ID. 2746 */ 2747 int 2748 channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) 2749 { 2750 struct sshbuf *b = NULL; 2751 Channel *downstream; 2752 const u_char *cp = NULL; 2753 size_t len; 2754 int r; 2755 2756 /* 2757 * When receiving packets from the peer we need to check whether we 2758 * need to forward the packets to the mux client. In this case we 2759 * restore the original channel id and keep track of CLOSE messages, 2760 * so we can cleanup the channel. 2761 */ 2762 if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) 2763 return 0; 2764 if ((downstream = c->mux_ctx) == NULL) 2765 return 0; 2766 switch (type) { 2767 case SSH2_MSG_CHANNEL_CLOSE: 2768 case SSH2_MSG_CHANNEL_DATA: 2769 case SSH2_MSG_CHANNEL_EOF: 2770 case SSH2_MSG_CHANNEL_EXTENDED_DATA: 2771 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2772 case SSH2_MSG_CHANNEL_OPEN_FAILURE: 2773 case SSH2_MSG_CHANNEL_WINDOW_ADJUST: 2774 case SSH2_MSG_CHANNEL_SUCCESS: 2775 case SSH2_MSG_CHANNEL_FAILURE: 2776 case SSH2_MSG_CHANNEL_REQUEST: 2777 break; 2778 default: 2779 debug2("%s: channel %u: unsupported type %u", __func__, 2780 c->self, type); 2781 return 0; 2782 } 2783 if ((b = sshbuf_new()) == NULL) { 2784 error("%s: alloc reply", __func__); 2785 goto out; 2786 } 2787 /* get remaining payload (after id) */ 2788 cp = sshpkt_ptr(ssh, &len); 2789 if (cp == NULL) { 2790 error("%s: no packet", __func__); 2791 goto out; 2792 } 2793 /* translate id and send to muxclient */ 2794 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 2795 (r = sshbuf_put_u8(b, type)) != 0 || 2796 (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || 2797 (r = sshbuf_put(b, cp, len)) != 0 || 2798 (r = sshbuf_put_stringb(downstream->output, b)) != 0) { 2799 error("%s: compose for muxclient %s", __func__, ssh_err(r)); 2800 goto out; 2801 } 2802 /* sshbuf_dump(b, stderr); */ 2803 if (ssh_packet_log_type(type)) 2804 debug3("%s: channel %u: up->down: type %u", __func__, c->self, 2805 type); 2806 out: 2807 /* update state */ 2808 switch (type) { 2809 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: 2810 /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ 2811 if (cp && len > 4) { 2812 c->remote_id = PEEK_U32(cp); 2813 c->have_remote_id = 1; 2814 } 2815 break; 2816 case SSH2_MSG_CHANNEL_CLOSE: 2817 if (c->flags & CHAN_CLOSE_SENT) 2818 channel_free(ssh, c); 2819 else 2820 c->flags |= CHAN_CLOSE_RCVD; 2821 break; 2822 } 2823 sshbuf_free(b); 2824 return 1; 2825 } 2826 2827 /* -- protocol input */ 2828 2829 /* Parse a channel ID from the current packet */ 2830 static int 2831 channel_parse_id(struct ssh *ssh, const char *where, const char *what) 2832 { 2833 u_int32_t id; 2834 int r; 2835 2836 if ((r = sshpkt_get_u32(ssh, &id)) != 0) { 2837 error("%s: parse id: %s", where, ssh_err(r)); 2838 ssh_packet_disconnect(ssh, "Invalid %s message", what); 2839 } 2840 if (id > INT_MAX) { 2841 error("%s: bad channel id %u: %s", where, id, ssh_err(r)); 2842 ssh_packet_disconnect(ssh, "Invalid %s channel id", what); 2843 } 2844 return (int)id; 2845 } 2846 2847 /* Lookup a channel from an ID in the current packet */ 2848 static Channel * 2849 channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) 2850 { 2851 int id = channel_parse_id(ssh, where, what); 2852 Channel *c; 2853 2854 if ((c = channel_lookup(ssh, id)) == NULL) { 2855 ssh_packet_disconnect(ssh, 2856 "%s packet referred to nonexistent channel %d", what, id); 2857 } 2858 return c; 2859 } 2860 2861 int 2862 channel_input_data(int type, u_int32_t seq, struct ssh *ssh) 2863 { 2864 const u_char *data; 2865 size_t data_len, win_len; 2866 Channel *c = channel_from_packet_id(ssh, __func__, "data"); 2867 int r; 2868 2869 if (channel_proxy_upstream(c, type, seq, ssh)) 2870 return 0; 2871 2872 /* Ignore any data for non-open channels (might happen on close) */ 2873 if (c->type != SSH_CHANNEL_OPEN && 2874 c->type != SSH_CHANNEL_RDYNAMIC_OPEN && 2875 c->type != SSH_CHANNEL_RDYNAMIC_FINISH && 2876 c->type != SSH_CHANNEL_X11_OPEN) 2877 return 0; 2878 2879 /* Get the data. */ 2880 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0) 2881 fatal("%s: channel %d: get data: %s", __func__, 2882 c->self, ssh_err(r)); 2883 ssh_packet_check_eom(ssh); 2884 2885 win_len = data_len; 2886 if (c->datagram) 2887 win_len += 4; /* string length header */ 2888 2889 /* 2890 * The sending side reduces its window as it sends data, so we 2891 * must 'fake' consumption of the data in order to ensure that window 2892 * updates are sent back. Otherwise the connection might deadlock. 2893 */ 2894 if (c->ostate != CHAN_OUTPUT_OPEN) { 2895 c->local_window -= win_len; 2896 c->local_consumed += win_len; 2897 return 0; 2898 } 2899 2900 if (win_len > c->local_maxpacket) { 2901 logit("channel %d: rcvd big packet %zu, maxpack %u", 2902 c->self, win_len, c->local_maxpacket); 2903 return 0; 2904 } 2905 if (win_len > c->local_window) { 2906 logit("channel %d: rcvd too much data %zu, win %u", 2907 c->self, win_len, c->local_window); 2908 return 0; 2909 } 2910 c->local_window -= win_len; 2911 2912 if (c->datagram) { 2913 if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) 2914 fatal("%s: channel %d: append datagram: %s", 2915 __func__, c->self, ssh_err(r)); 2916 } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) 2917 fatal("%s: channel %d: append data: %s", 2918 __func__, c->self, ssh_err(r)); 2919 2920 return 0; 2921 } 2922 2923 int 2924 channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) 2925 { 2926 const u_char *data; 2927 size_t data_len; 2928 u_int32_t tcode; 2929 Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); 2930 int r; 2931 2932 if (channel_proxy_upstream(c, type, seq, ssh)) 2933 return 0; 2934 if (c->type != SSH_CHANNEL_OPEN) { 2935 logit("channel %d: ext data for non open", c->self); 2936 return 0; 2937 } 2938 if (c->flags & CHAN_EOF_RCVD) { 2939 if (datafellows & SSH_BUG_EXTEOF) 2940 debug("channel %d: accepting ext data after eof", 2941 c->self); 2942 else 2943 ssh_packet_disconnect(ssh, "Received extended_data " 2944 "after EOF on channel %d.", c->self); 2945 } 2946 2947 if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { 2948 error("%s: parse tcode: %s", __func__, ssh_err(r)); 2949 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 2950 } 2951 if (c->efd == -1 || 2952 c->extended_usage != CHAN_EXTENDED_WRITE || 2953 tcode != SSH2_EXTENDED_DATA_STDERR) { 2954 logit("channel %d: bad ext data", c->self); 2955 return 0; 2956 } 2957 if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0) { 2958 error("%s: parse data: %s", __func__, ssh_err(r)); 2959 ssh_packet_disconnect(ssh, "Invalid extended_data message"); 2960 } 2961 ssh_packet_check_eom(ssh); 2962 2963 if (data_len > c->local_window) { 2964 logit("channel %d: rcvd too much extended_data %zu, win %u", 2965 c->self, data_len, c->local_window); 2966 return 0; 2967 } 2968 debug2("channel %d: rcvd ext data %zu", c->self, data_len); 2969 /* XXX sshpkt_getb? */ 2970 if ((r = sshbuf_put(c->extended, data, data_len)) != 0) 2971 error("%s: append: %s", __func__, ssh_err(r)); 2972 c->local_window -= data_len; 2973 return 0; 2974 } 2975 2976 int 2977 channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) 2978 { 2979 Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); 2980 2981 ssh_packet_check_eom(ssh); 2982 2983 if (channel_proxy_upstream(c, type, seq, ssh)) 2984 return 0; 2985 chan_rcvd_ieof(ssh, c); 2986 2987 /* XXX force input close */ 2988 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 2989 debug("channel %d: FORCE input drain", c->self); 2990 c->istate = CHAN_INPUT_WAIT_DRAIN; 2991 if (sshbuf_len(c->input) == 0) 2992 chan_ibuf_empty(ssh, c); 2993 } 2994 return 0; 2995 } 2996 2997 int 2998 channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) 2999 { 3000 Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); 3001 3002 if (channel_proxy_upstream(c, type, seq, ssh)) 3003 return 0; 3004 ssh_packet_check_eom(ssh); 3005 chan_rcvd_oclose(ssh, c); 3006 return 0; 3007 } 3008 3009 int 3010 channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) 3011 { 3012 Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); 3013 u_int32_t remote_window, remote_maxpacket; 3014 int r; 3015 3016 if (channel_proxy_upstream(c, type, seq, ssh)) 3017 return 0; 3018 if (c->type != SSH_CHANNEL_OPENING) 3019 packet_disconnect("Received open confirmation for " 3020 "non-opening channel %d.", c->self); 3021 /* 3022 * Record the remote channel number and mark that the channel 3023 * is now open. 3024 */ 3025 if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || 3026 (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || 3027 (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0) { 3028 error("%s: window/maxpacket: %s", __func__, ssh_err(r)); 3029 packet_disconnect("Invalid open confirmation message"); 3030 } 3031 ssh_packet_check_eom(ssh); 3032 3033 c->have_remote_id = 1; 3034 c->remote_window = remote_window; 3035 c->remote_maxpacket = remote_maxpacket; 3036 c->type = SSH_CHANNEL_OPEN; 3037 if (c->open_confirm) { 3038 debug2("%s: channel %d: callback start", __func__, c->self); 3039 c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); 3040 debug2("%s: channel %d: callback done", __func__, c->self); 3041 } 3042 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 3043 c->remote_window, c->remote_maxpacket); 3044 return 0; 3045 } 3046 3047 static char * 3048 reason2txt(int reason) 3049 { 3050 switch (reason) { 3051 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 3052 return "administratively prohibited"; 3053 case SSH2_OPEN_CONNECT_FAILED: 3054 return "connect failed"; 3055 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 3056 return "unknown channel type"; 3057 case SSH2_OPEN_RESOURCE_SHORTAGE: 3058 return "resource shortage"; 3059 } 3060 return "unknown reason"; 3061 } 3062 3063 int 3064 channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) 3065 { 3066 Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); 3067 u_int32_t reason; 3068 char *msg = NULL; 3069 int r; 3070 3071 if (channel_proxy_upstream(c, type, seq, ssh)) 3072 return 0; 3073 if (c->type != SSH_CHANNEL_OPENING) 3074 packet_disconnect("Received open failure for " 3075 "non-opening channel %d.", c->self); 3076 if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { 3077 error("%s: reason: %s", __func__, ssh_err(r)); 3078 packet_disconnect("Invalid open failure message"); 3079 } 3080 /* skip language */ 3081 if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 3082 (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0) { 3083 error("%s: message/lang: %s", __func__, ssh_err(r)); 3084 packet_disconnect("Invalid open failure message"); 3085 } 3086 ssh_packet_check_eom(ssh); 3087 logit("channel %d: open failed: %s%s%s", c->self, 3088 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 3089 free(msg); 3090 if (c->open_confirm) { 3091 debug2("%s: channel %d: callback start", __func__, c->self); 3092 c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); 3093 debug2("%s: channel %d: callback done", __func__, c->self); 3094 } 3095 /* Schedule the channel for cleanup/deletion. */ 3096 chan_mark_dead(ssh, c); 3097 return 0; 3098 } 3099 3100 int 3101 channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) 3102 { 3103 int id = channel_parse_id(ssh, __func__, "window adjust"); 3104 Channel *c; 3105 u_int32_t adjust; 3106 u_int new_rwin; 3107 int r; 3108 3109 if ((c = channel_lookup(ssh, id)) == NULL) { 3110 logit("Received window adjust for non-open channel %d.", id); 3111 return 0; 3112 } 3113 3114 if (channel_proxy_upstream(c, type, seq, ssh)) 3115 return 0; 3116 if ((r = sshpkt_get_u32(ssh, &adjust)) != 0) { 3117 error("%s: adjust: %s", __func__, ssh_err(r)); 3118 packet_disconnect("Invalid window adjust message"); 3119 } 3120 ssh_packet_check_eom(ssh); 3121 debug2("channel %d: rcvd adjust %u", c->self, adjust); 3122 if ((new_rwin = c->remote_window + adjust) < c->remote_window) { 3123 fatal("channel %d: adjust %u overflows remote window %u", 3124 c->self, adjust, c->remote_window); 3125 } 3126 c->remote_window = new_rwin; 3127 return 0; 3128 } 3129 3130 int 3131 channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) 3132 { 3133 int id = channel_parse_id(ssh, __func__, "status confirm"); 3134 Channel *c; 3135 struct channel_confirm *cc; 3136 3137 /* Reset keepalive timeout */ 3138 packet_set_alive_timeouts(0); 3139 3140 debug2("%s: type %d id %d", __func__, type, id); 3141 3142 if ((c = channel_lookup(ssh, id)) == NULL) { 3143 logit("%s: %d: unknown", __func__, id); 3144 return 0; 3145 } 3146 if (channel_proxy_upstream(c, type, seq, ssh)) 3147 return 0; 3148 ssh_packet_check_eom(ssh); 3149 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 3150 return 0; 3151 cc->cb(ssh, type, c, cc->ctx); 3152 TAILQ_REMOVE(&c->status_confirms, cc, entry); 3153 explicit_bzero(cc, sizeof(*cc)); 3154 free(cc); 3155 return 0; 3156 } 3157 3158 /* -- tcp forwarding */ 3159 3160 void 3161 channel_set_af(struct ssh *ssh, int af) 3162 { 3163 ssh->chanctxt->IPv4or6 = af; 3164 } 3165 3166 3167 /* 3168 * Determine whether or not a port forward listens to loopback, the 3169 * specified address or wildcard. On the client, a specified bind 3170 * address will always override gateway_ports. On the server, a 3171 * gateway_ports of 1 (``yes'') will override the client's specification 3172 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 3173 * will bind to whatever address the client asked for. 3174 * 3175 * Special-case listen_addrs are: 3176 * 3177 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 3178 * "" (empty string), "*" -> wildcard v4/v6 3179 * "localhost" -> loopback v4/v6 3180 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 3181 */ 3182 static const char * 3183 channel_fwd_bind_addr(const char *listen_addr, int *wildcardp, 3184 int is_client, struct ForwardOptions *fwd_opts) 3185 { 3186 const char *addr = NULL; 3187 int wildcard = 0; 3188 3189 if (listen_addr == NULL) { 3190 /* No address specified: default to gateway_ports setting */ 3191 if (fwd_opts->gateway_ports) 3192 wildcard = 1; 3193 } else if (fwd_opts->gateway_ports || is_client) { 3194 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 3195 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 3196 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 3197 (!is_client && fwd_opts->gateway_ports == 1)) { 3198 wildcard = 1; 3199 /* 3200 * Notify client if they requested a specific listen 3201 * address and it was overridden. 3202 */ 3203 if (*listen_addr != '\0' && 3204 strcmp(listen_addr, "0.0.0.0") != 0 && 3205 strcmp(listen_addr, "*") != 0) { 3206 packet_send_debug("Forwarding listen address " 3207 "\"%s\" overridden by server " 3208 "GatewayPorts", listen_addr); 3209 } 3210 } else if (strcmp(listen_addr, "localhost") != 0 || 3211 strcmp(listen_addr, "127.0.0.1") == 0 || 3212 strcmp(listen_addr, "::1") == 0) { 3213 /* Accept localhost address when GatewayPorts=yes */ 3214 addr = listen_addr; 3215 } 3216 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 3217 strcmp(listen_addr, "::1") == 0) { 3218 /* 3219 * If a specific IPv4/IPv6 localhost address has been 3220 * requested then accept it even if gateway_ports is in 3221 * effect. This allows the client to prefer IPv4 or IPv6. 3222 */ 3223 addr = listen_addr; 3224 } 3225 if (wildcardp != NULL) 3226 *wildcardp = wildcard; 3227 return addr; 3228 } 3229 3230 static int 3231 channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, 3232 struct Forward *fwd, int *allocated_listen_port, 3233 struct ForwardOptions *fwd_opts) 3234 { 3235 Channel *c; 3236 int sock, r, success = 0, wildcard = 0, is_client; 3237 struct addrinfo hints, *ai, *aitop; 3238 const char *host, *addr; 3239 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3240 in_port_t *lport_p; 3241 3242 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 3243 3244 if (is_client && fwd->connect_path != NULL) { 3245 host = fwd->connect_path; 3246 } else { 3247 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 3248 fwd->listen_host : fwd->connect_host; 3249 if (host == NULL) { 3250 error("No forward host name."); 3251 return 0; 3252 } 3253 if (strlen(host) >= NI_MAXHOST) { 3254 error("Forward host name too long."); 3255 return 0; 3256 } 3257 } 3258 3259 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 3260 addr = channel_fwd_bind_addr(fwd->listen_host, &wildcard, 3261 is_client, fwd_opts); 3262 debug3("%s: type %d wildcard %d addr %s", __func__, 3263 type, wildcard, (addr == NULL) ? "NULL" : addr); 3264 3265 /* 3266 * getaddrinfo returns a loopback address if the hostname is 3267 * set to NULL and hints.ai_flags is not AI_PASSIVE 3268 */ 3269 memset(&hints, 0, sizeof(hints)); 3270 hints.ai_family = ssh->chanctxt->IPv4or6; 3271 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 3272 hints.ai_socktype = SOCK_STREAM; 3273 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 3274 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 3275 if (addr == NULL) { 3276 /* This really shouldn't happen */ 3277 packet_disconnect("getaddrinfo: fatal error: %s", 3278 ssh_gai_strerror(r)); 3279 } else { 3280 error("%s: getaddrinfo(%.64s): %s", __func__, addr, 3281 ssh_gai_strerror(r)); 3282 } 3283 return 0; 3284 } 3285 if (allocated_listen_port != NULL) 3286 *allocated_listen_port = 0; 3287 for (ai = aitop; ai; ai = ai->ai_next) { 3288 switch (ai->ai_family) { 3289 case AF_INET: 3290 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 3291 sin_port; 3292 break; 3293 case AF_INET6: 3294 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 3295 sin6_port; 3296 break; 3297 default: 3298 continue; 3299 } 3300 /* 3301 * If allocating a port for -R forwards, then use the 3302 * same port for all address families. 3303 */ 3304 if (type == SSH_CHANNEL_RPORT_LISTENER && 3305 fwd->listen_port == 0 && allocated_listen_port != NULL && 3306 *allocated_listen_port > 0) 3307 *lport_p = htons(*allocated_listen_port); 3308 3309 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 3310 strport, sizeof(strport), 3311 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3312 error("%s: getnameinfo failed", __func__); 3313 continue; 3314 } 3315 /* Create a port to listen for the host. */ 3316 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3317 if (sock < 0) { 3318 /* this is no error since kernel may not support ipv6 */ 3319 verbose("socket [%s]:%s: %.100s", ntop, strport, 3320 strerror(errno)); 3321 continue; 3322 } 3323 3324 set_reuseaddr(sock); 3325 3326 debug("Local forwarding listening on %s port %s.", 3327 ntop, strport); 3328 3329 /* Bind the socket to the address. */ 3330 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3331 /* 3332 * address can be in if use ipv6 address is 3333 * already bound 3334 */ 3335 verbose("bind [%s]:%s: %.100s", 3336 ntop, strport, strerror(errno)); 3337 close(sock); 3338 continue; 3339 } 3340 /* Start listening for connections on the socket. */ 3341 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 3342 error("listen [%s]:%s: %.100s", ntop, strport, 3343 strerror(errno)); 3344 close(sock); 3345 continue; 3346 } 3347 3348 /* 3349 * fwd->listen_port == 0 requests a dynamically allocated port - 3350 * record what we got. 3351 */ 3352 if (type == SSH_CHANNEL_RPORT_LISTENER && 3353 fwd->listen_port == 0 && 3354 allocated_listen_port != NULL && 3355 *allocated_listen_port == 0) { 3356 *allocated_listen_port = get_local_port(sock); 3357 debug("Allocated listen port %d", 3358 *allocated_listen_port); 3359 } 3360 3361 /* Allocate a channel number for the socket. */ 3362 c = channel_new(ssh, "port listener", type, sock, sock, -1, 3363 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3364 0, "port listener", 1); 3365 c->path = xstrdup(host); 3366 c->host_port = fwd->connect_port; 3367 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 3368 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 3369 !(datafellows & SSH_BUG_DYNAMIC_RPORT)) 3370 c->listening_port = *allocated_listen_port; 3371 else 3372 c->listening_port = fwd->listen_port; 3373 success = 1; 3374 } 3375 if (success == 0) 3376 error("%s: cannot listen to port: %d", __func__, 3377 fwd->listen_port); 3378 freeaddrinfo(aitop); 3379 return success; 3380 } 3381 3382 static int 3383 channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, 3384 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3385 { 3386 struct sockaddr_un sunaddr; 3387 const char *path; 3388 Channel *c; 3389 int port, sock; 3390 mode_t omask; 3391 3392 switch (type) { 3393 case SSH_CHANNEL_UNIX_LISTENER: 3394 if (fwd->connect_path != NULL) { 3395 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 3396 error("Local connecting path too long: %s", 3397 fwd->connect_path); 3398 return 0; 3399 } 3400 path = fwd->connect_path; 3401 port = PORT_STREAMLOCAL; 3402 } else { 3403 if (fwd->connect_host == NULL) { 3404 error("No forward host name."); 3405 return 0; 3406 } 3407 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 3408 error("Forward host name too long."); 3409 return 0; 3410 } 3411 path = fwd->connect_host; 3412 port = fwd->connect_port; 3413 } 3414 break; 3415 case SSH_CHANNEL_RUNIX_LISTENER: 3416 path = fwd->listen_path; 3417 port = PORT_STREAMLOCAL; 3418 break; 3419 default: 3420 error("%s: unexpected channel type %d", __func__, type); 3421 return 0; 3422 } 3423 3424 if (fwd->listen_path == NULL) { 3425 error("No forward path name."); 3426 return 0; 3427 } 3428 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 3429 error("Local listening path too long: %s", fwd->listen_path); 3430 return 0; 3431 } 3432 3433 debug3("%s: type %d path %s", __func__, type, fwd->listen_path); 3434 3435 /* Start a Unix domain listener. */ 3436 omask = umask(fwd_opts->streamlocal_bind_mask); 3437 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 3438 fwd_opts->streamlocal_bind_unlink); 3439 umask(omask); 3440 if (sock < 0) 3441 return 0; 3442 3443 debug("Local forwarding listening on path %s.", fwd->listen_path); 3444 3445 /* Allocate a channel number for the socket. */ 3446 c = channel_new(ssh, "unix listener", type, sock, sock, -1, 3447 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 3448 0, "unix listener", 1); 3449 c->path = xstrdup(path); 3450 c->host_port = port; 3451 c->listening_port = PORT_STREAMLOCAL; 3452 c->listening_addr = xstrdup(fwd->listen_path); 3453 return 1; 3454 } 3455 3456 static int 3457 channel_cancel_rport_listener_tcpip(struct ssh *ssh, 3458 const char *host, u_short port) 3459 { 3460 u_int i; 3461 int found = 0; 3462 3463 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3464 Channel *c = ssh->chanctxt->channels[i]; 3465 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3466 continue; 3467 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3468 debug2("%s: close channel %d", __func__, i); 3469 channel_free(ssh, c); 3470 found = 1; 3471 } 3472 } 3473 3474 return found; 3475 } 3476 3477 static int 3478 channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) 3479 { 3480 u_int i; 3481 int found = 0; 3482 3483 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3484 Channel *c = ssh->chanctxt->channels[i]; 3485 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3486 continue; 3487 if (c->path == NULL) 3488 continue; 3489 if (strcmp(c->path, path) == 0) { 3490 debug2("%s: close channel %d", __func__, i); 3491 channel_free(ssh, c); 3492 found = 1; 3493 } 3494 } 3495 3496 return found; 3497 } 3498 3499 int 3500 channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) 3501 { 3502 if (fwd->listen_path != NULL) { 3503 return channel_cancel_rport_listener_streamlocal(ssh, 3504 fwd->listen_path); 3505 } else { 3506 return channel_cancel_rport_listener_tcpip(ssh, 3507 fwd->listen_host, fwd->listen_port); 3508 } 3509 } 3510 3511 static int 3512 channel_cancel_lport_listener_tcpip(struct ssh *ssh, 3513 const char *lhost, u_short lport, int cport, 3514 struct ForwardOptions *fwd_opts) 3515 { 3516 u_int i; 3517 int found = 0; 3518 const char *addr = channel_fwd_bind_addr(lhost, NULL, 1, fwd_opts); 3519 3520 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3521 Channel *c = ssh->chanctxt->channels[i]; 3522 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 3523 continue; 3524 if (c->listening_port != lport) 3525 continue; 3526 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 3527 /* skip dynamic forwardings */ 3528 if (c->host_port == 0) 3529 continue; 3530 } else { 3531 if (c->host_port != cport) 3532 continue; 3533 } 3534 if ((c->listening_addr == NULL && addr != NULL) || 3535 (c->listening_addr != NULL && addr == NULL)) 3536 continue; 3537 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 3538 debug2("%s: close channel %d", __func__, i); 3539 channel_free(ssh, c); 3540 found = 1; 3541 } 3542 } 3543 3544 return found; 3545 } 3546 3547 static int 3548 channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) 3549 { 3550 u_int i; 3551 int found = 0; 3552 3553 if (path == NULL) { 3554 error("%s: no path specified.", __func__); 3555 return 0; 3556 } 3557 3558 for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { 3559 Channel *c = ssh->chanctxt->channels[i]; 3560 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 3561 continue; 3562 if (c->listening_addr == NULL) 3563 continue; 3564 if (strcmp(c->listening_addr, path) == 0) { 3565 debug2("%s: close channel %d", __func__, i); 3566 channel_free(ssh, c); 3567 found = 1; 3568 } 3569 } 3570 3571 return found; 3572 } 3573 3574 int 3575 channel_cancel_lport_listener(struct ssh *ssh, 3576 struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 3577 { 3578 if (fwd->listen_path != NULL) { 3579 return channel_cancel_lport_listener_streamlocal(ssh, 3580 fwd->listen_path); 3581 } else { 3582 return channel_cancel_lport_listener_tcpip(ssh, 3583 fwd->listen_host, fwd->listen_port, cport, fwd_opts); 3584 } 3585 } 3586 3587 /* protocol local port fwd, used by ssh */ 3588 int 3589 channel_setup_local_fwd_listener(struct ssh *ssh, 3590 struct Forward *fwd, struct ForwardOptions *fwd_opts) 3591 { 3592 if (fwd->listen_path != NULL) { 3593 return channel_setup_fwd_listener_streamlocal(ssh, 3594 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 3595 } else { 3596 return channel_setup_fwd_listener_tcpip(ssh, 3597 SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); 3598 } 3599 } 3600 3601 /* protocol v2 remote port fwd, used by sshd */ 3602 int 3603 channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, 3604 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 3605 { 3606 if (fwd->listen_path != NULL) { 3607 return channel_setup_fwd_listener_streamlocal(ssh, 3608 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 3609 } else { 3610 return channel_setup_fwd_listener_tcpip(ssh, 3611 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 3612 fwd_opts); 3613 } 3614 } 3615 3616 /* 3617 * Translate the requested rfwd listen host to something usable for 3618 * this server. 3619 */ 3620 static const char * 3621 channel_rfwd_bind_host(const char *listen_host) 3622 { 3623 if (listen_host == NULL) { 3624 return "localhost"; 3625 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 3626 return ""; 3627 } else 3628 return listen_host; 3629 } 3630 3631 /* 3632 * Initiate forwarding of connections to port "port" on remote host through 3633 * the secure channel to host:port from local side. 3634 * Returns handle (index) for updating the dynamic listen port with 3635 * channel_update_permitted_opens(). 3636 */ 3637 int 3638 channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) 3639 { 3640 int r, success = 0, idx = -1; 3641 char *host_to_connect, *listen_host, *listen_path; 3642 int port_to_connect, listen_port; 3643 3644 /* Send the forward request to the remote side. */ 3645 if (fwd->listen_path != NULL) { 3646 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3647 (r = sshpkt_put_cstring(ssh, 3648 "streamlocal-forward@openssh.com")) != 0 || 3649 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 3650 (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || 3651 (r = sshpkt_send(ssh)) != 0 || 3652 (r = ssh_packet_write_wait(ssh)) != 0) 3653 fatal("%s: request streamlocal: %s", 3654 __func__, ssh_err(r)); 3655 } else { 3656 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3657 (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || 3658 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ 3659 (r = sshpkt_put_cstring(ssh, 3660 channel_rfwd_bind_host(fwd->listen_host))) != 0 || 3661 (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || 3662 (r = sshpkt_send(ssh)) != 0 || 3663 (r = ssh_packet_write_wait(ssh)) != 0) 3664 fatal("%s: request tcpip-forward: %s", 3665 __func__, ssh_err(r)); 3666 } 3667 /* Assume that server accepts the request */ 3668 success = 1; 3669 if (success) { 3670 /* Record that connection to this host/port is permitted. */ 3671 host_to_connect = listen_host = listen_path = NULL; 3672 port_to_connect = listen_port = 0; 3673 if (fwd->connect_path != NULL) { 3674 host_to_connect = xstrdup(fwd->connect_path); 3675 port_to_connect = PORT_STREAMLOCAL; 3676 } else { 3677 host_to_connect = xstrdup(fwd->connect_host); 3678 port_to_connect = fwd->connect_port; 3679 } 3680 if (fwd->listen_path != NULL) { 3681 listen_path = xstrdup(fwd->listen_path); 3682 listen_port = PORT_STREAMLOCAL; 3683 } else { 3684 if (fwd->listen_host != NULL) 3685 listen_host = xstrdup(fwd->listen_host); 3686 listen_port = fwd->listen_port; 3687 } 3688 idx = fwd_perm_list_add(ssh, FWDPERM_USER, 3689 host_to_connect, port_to_connect, 3690 listen_host, listen_path, listen_port, NULL); 3691 } 3692 return idx; 3693 } 3694 3695 static int 3696 open_match(ForwardPermission *allowed_open, const char *requestedhost, 3697 int requestedport) 3698 { 3699 if (allowed_open->host_to_connect == NULL) 3700 return 0; 3701 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 3702 allowed_open->port_to_connect != requestedport) 3703 return 0; 3704 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 3705 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 3706 return 0; 3707 return 1; 3708 } 3709 3710 /* 3711 * Note that in the listen host/port case 3712 * we don't support FWD_PERMIT_ANY_PORT and 3713 * need to translate between the configured-host (listen_host) 3714 * and what we've sent to the remote server (channel_rfwd_bind_host) 3715 */ 3716 static int 3717 open_listen_match_tcpip(ForwardPermission *allowed_open, 3718 const char *requestedhost, u_short requestedport, int translate) 3719 { 3720 const char *allowed_host; 3721 3722 if (allowed_open->host_to_connect == NULL) 3723 return 0; 3724 if (allowed_open->listen_port != requestedport) 3725 return 0; 3726 if (!translate && allowed_open->listen_host == NULL && 3727 requestedhost == NULL) 3728 return 1; 3729 allowed_host = translate ? 3730 channel_rfwd_bind_host(allowed_open->listen_host) : 3731 allowed_open->listen_host; 3732 if (allowed_host == NULL || 3733 strcmp(allowed_host, requestedhost) != 0) 3734 return 0; 3735 return 1; 3736 } 3737 3738 static int 3739 open_listen_match_streamlocal(ForwardPermission *allowed_open, 3740 const char *requestedpath) 3741 { 3742 if (allowed_open->host_to_connect == NULL) 3743 return 0; 3744 if (allowed_open->listen_port != PORT_STREAMLOCAL) 3745 return 0; 3746 if (allowed_open->listen_path == NULL || 3747 strcmp(allowed_open->listen_path, requestedpath) != 0) 3748 return 0; 3749 return 1; 3750 } 3751 3752 /* 3753 * Request cancellation of remote forwarding of connection host:port from 3754 * local side. 3755 */ 3756 static int 3757 channel_request_rforward_cancel_tcpip(struct ssh *ssh, 3758 const char *host, u_short port) 3759 { 3760 struct ssh_channels *sc = ssh->chanctxt; 3761 int r; 3762 u_int i; 3763 ForwardPermission *fp; 3764 3765 for (i = 0; i < sc->num_permitted_opens; i++) { 3766 fp = &sc->permitted_opens[i]; 3767 if (open_listen_match_tcpip(fp, host, port, 0)) 3768 break; 3769 fp = NULL; 3770 } 3771 if (fp == NULL) { 3772 debug("%s: requested forward not found", __func__); 3773 return -1; 3774 } 3775 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3776 (r = sshpkt_put_cstring(ssh, "cancel-tcpip-forward")) != 0 || 3777 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 3778 (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || 3779 (r = sshpkt_put_u32(ssh, port)) != 0 || 3780 (r = sshpkt_send(ssh)) != 0) 3781 fatal("%s: send cancel: %s", __func__, ssh_err(r)); 3782 3783 fwd_perm_clear(fp); /* unregister */ 3784 3785 return 0; 3786 } 3787 3788 /* 3789 * Request cancellation of remote forwarding of Unix domain socket 3790 * path from local side. 3791 */ 3792 static int 3793 channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) 3794 { 3795 struct ssh_channels *sc = ssh->chanctxt; 3796 int r; 3797 u_int i; 3798 ForwardPermission *fp; 3799 3800 for (i = 0; i < sc->num_permitted_opens; i++) { 3801 fp = &sc->permitted_opens[i]; 3802 if (open_listen_match_streamlocal(fp, path)) 3803 break; 3804 fp = NULL; 3805 } 3806 if (fp == NULL) { 3807 debug("%s: requested forward not found", __func__); 3808 return -1; 3809 } 3810 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 3811 (r = sshpkt_put_cstring(ssh, 3812 "cancel-streamlocal-forward@openssh.com")) != 0 || 3813 (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ 3814 (r = sshpkt_put_cstring(ssh, path)) != 0 || 3815 (r = sshpkt_send(ssh)) != 0) 3816 fatal("%s: send cancel: %s", __func__, ssh_err(r)); 3817 3818 fwd_perm_clear(fp); /* unregister */ 3819 3820 return 0; 3821 } 3822 3823 /* 3824 * Request cancellation of remote forwarding of a connection from local side. 3825 */ 3826 int 3827 channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) 3828 { 3829 if (fwd->listen_path != NULL) { 3830 return channel_request_rforward_cancel_streamlocal(ssh, 3831 fwd->listen_path); 3832 } else { 3833 return channel_request_rforward_cancel_tcpip(ssh, 3834 fwd->listen_host, 3835 fwd->listen_port ? fwd->listen_port : fwd->allocated_port); 3836 } 3837 } 3838 3839 /* 3840 * Permits opening to any host/port if permitted_opens[] is empty. This is 3841 * usually called by the server, because the user could connect to any port 3842 * anyway, and the server has no way to know but to trust the client anyway. 3843 */ 3844 void 3845 channel_permit_all_opens(struct ssh *ssh) 3846 { 3847 if (ssh->chanctxt->num_permitted_opens == 0) 3848 ssh->chanctxt->all_opens_permitted = 1; 3849 } 3850 3851 void 3852 channel_add_permitted_opens(struct ssh *ssh, char *host, int port) 3853 { 3854 struct ssh_channels *sc = ssh->chanctxt; 3855 3856 debug("allow port forwarding to host %s port %d", host, port); 3857 fwd_perm_list_add(ssh, FWDPERM_USER, host, port, NULL, NULL, 0, NULL); 3858 sc->all_opens_permitted = 0; 3859 } 3860 3861 /* 3862 * Update the listen port for a dynamic remote forward, after 3863 * the actual 'newport' has been allocated. If 'newport' < 0 is 3864 * passed then they entry will be invalidated. 3865 */ 3866 void 3867 channel_update_permitted_opens(struct ssh *ssh, int idx, int newport) 3868 { 3869 struct ssh_channels *sc = ssh->chanctxt; 3870 3871 if (idx < 0 || (u_int)idx >= sc->num_permitted_opens) { 3872 debug("%s: index out of range: %d num_permitted_opens %d", 3873 __func__, idx, sc->num_permitted_opens); 3874 return; 3875 } 3876 debug("%s allowed port %d for forwarding to host %s port %d", 3877 newport > 0 ? "Updating" : "Removing", 3878 newport, 3879 sc->permitted_opens[idx].host_to_connect, 3880 sc->permitted_opens[idx].port_to_connect); 3881 if (newport <= 0) 3882 fwd_perm_clear(&sc->permitted_opens[idx]); 3883 else { 3884 sc->permitted_opens[idx].listen_port = 3885 (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 3886 } 3887 } 3888 3889 int 3890 channel_add_adm_permitted_opens(struct ssh *ssh, char *host, int port) 3891 { 3892 debug("config allows port forwarding to host %s port %d", host, port); 3893 return fwd_perm_list_add(ssh, FWDPERM_ADMIN, host, port, 3894 NULL, NULL, 0, NULL); 3895 } 3896 3897 void 3898 channel_disable_adm_local_opens(struct ssh *ssh) 3899 { 3900 channel_clear_adm_permitted_opens(ssh); 3901 fwd_perm_list_add(ssh, FWDPERM_ADMIN, NULL, 0, NULL, NULL, 0, NULL); 3902 } 3903 3904 void 3905 channel_clear_permitted_opens(struct ssh *ssh) 3906 { 3907 struct ssh_channels *sc = ssh->chanctxt; 3908 3909 sc->permitted_opens = xrecallocarray(sc->permitted_opens, 3910 sc->num_permitted_opens, 0, sizeof(*sc->permitted_opens)); 3911 sc->num_permitted_opens = 0; 3912 } 3913 3914 void 3915 channel_clear_adm_permitted_opens(struct ssh *ssh) 3916 { 3917 struct ssh_channels *sc = ssh->chanctxt; 3918 3919 sc->permitted_adm_opens = xrecallocarray(sc->permitted_adm_opens, 3920 sc->num_adm_permitted_opens, 0, sizeof(*sc->permitted_adm_opens)); 3921 sc->num_adm_permitted_opens = 0; 3922 } 3923 3924 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 3925 int 3926 permitopen_port(const char *p) 3927 { 3928 int port; 3929 3930 if (strcmp(p, "*") == 0) 3931 return FWD_PERMIT_ANY_PORT; 3932 if ((port = a2port(p)) > 0) 3933 return port; 3934 return -1; 3935 } 3936 3937 /* Try to start non-blocking connect to next host in cctx list */ 3938 static int 3939 connect_next(struct channel_connect *cctx) 3940 { 3941 int sock, saved_errno; 3942 struct sockaddr_un *sunaddr; 3943 char ntop[NI_MAXHOST]; 3944 char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; 3945 3946 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 3947 switch (cctx->ai->ai_family) { 3948 case AF_UNIX: 3949 /* unix:pathname instead of host:port */ 3950 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 3951 strlcpy(ntop, "unix", sizeof(ntop)); 3952 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 3953 break; 3954 case AF_INET: 3955 case AF_INET6: 3956 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 3957 ntop, sizeof(ntop), strport, sizeof(strport), 3958 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3959 error("connect_next: getnameinfo failed"); 3960 continue; 3961 } 3962 break; 3963 default: 3964 continue; 3965 } 3966 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 3967 cctx->ai->ai_protocol)) == -1) { 3968 if (cctx->ai->ai_next == NULL) 3969 error("socket: %.100s", strerror(errno)); 3970 else 3971 verbose("socket: %.100s", strerror(errno)); 3972 continue; 3973 } 3974 if (set_nonblock(sock) == -1) 3975 fatal("%s: set_nonblock(%d)", __func__, sock); 3976 if (connect(sock, cctx->ai->ai_addr, 3977 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 3978 debug("connect_next: host %.100s ([%.100s]:%s): " 3979 "%.100s", cctx->host, ntop, strport, 3980 strerror(errno)); 3981 saved_errno = errno; 3982 close(sock); 3983 errno = saved_errno; 3984 continue; /* fail -- try next */ 3985 } 3986 if (cctx->ai->ai_family != AF_UNIX) 3987 set_nodelay(sock); 3988 debug("connect_next: host %.100s ([%.100s]:%s) " 3989 "in progress, fd=%d", cctx->host, ntop, strport, sock); 3990 cctx->ai = cctx->ai->ai_next; 3991 return sock; 3992 } 3993 return -1; 3994 } 3995 3996 static void 3997 channel_connect_ctx_free(struct channel_connect *cctx) 3998 { 3999 free(cctx->host); 4000 if (cctx->aitop) { 4001 if (cctx->aitop->ai_family == AF_UNIX) 4002 free(cctx->aitop); 4003 else 4004 freeaddrinfo(cctx->aitop); 4005 } 4006 memset(cctx, 0, sizeof(*cctx)); 4007 } 4008 4009 /* 4010 * Return connecting socket to remote host:port or local socket path, 4011 * passing back the failure reason if appropriate. 4012 */ 4013 static int 4014 connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, 4015 char *ctype, char *rname, struct channel_connect *cctx, 4016 int *reason, const char **errmsg) 4017 { 4018 struct addrinfo hints; 4019 int gaierr; 4020 int sock = -1; 4021 char strport[NI_MAXSERV]; 4022 4023 if (port == PORT_STREAMLOCAL) { 4024 struct sockaddr_un *sunaddr; 4025 struct addrinfo *ai; 4026 4027 if (strlen(name) > sizeof(sunaddr->sun_path)) { 4028 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 4029 return -1; 4030 } 4031 4032 /* 4033 * Fake up a struct addrinfo for AF_UNIX connections. 4034 * channel_connect_ctx_free() must check ai_family 4035 * and use free() not freeaddirinfo() for AF_UNIX. 4036 */ 4037 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 4038 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 4039 ai->ai_addr = (struct sockaddr *)(ai + 1); 4040 ai->ai_addrlen = sizeof(*sunaddr); 4041 ai->ai_family = AF_UNIX; 4042 ai->ai_socktype = socktype; 4043 ai->ai_protocol = PF_UNSPEC; 4044 sunaddr = (struct sockaddr_un *)ai->ai_addr; 4045 sunaddr->sun_family = AF_UNIX; 4046 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 4047 cctx->aitop = ai; 4048 } else { 4049 memset(&hints, 0, sizeof(hints)); 4050 hints.ai_family = ssh->chanctxt->IPv4or6; 4051 hints.ai_socktype = socktype; 4052 snprintf(strport, sizeof strport, "%d", port); 4053 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) 4054 != 0) { 4055 if (errmsg != NULL) 4056 *errmsg = ssh_gai_strerror(gaierr); 4057 if (reason != NULL) 4058 *reason = SSH2_OPEN_CONNECT_FAILED; 4059 error("connect_to %.100s: unknown host (%s)", name, 4060 ssh_gai_strerror(gaierr)); 4061 return -1; 4062 } 4063 } 4064 4065 cctx->host = xstrdup(name); 4066 cctx->port = port; 4067 cctx->ai = cctx->aitop; 4068 4069 if ((sock = connect_next(cctx)) == -1) { 4070 error("connect to %.100s port %d failed: %s", 4071 name, port, strerror(errno)); 4072 return -1; 4073 } 4074 4075 return sock; 4076 } 4077 4078 /* Return CONNECTING channel to remote host:port or local socket path */ 4079 static Channel * 4080 connect_to(struct ssh *ssh, const char *host, int port, 4081 char *ctype, char *rname) 4082 { 4083 struct channel_connect cctx; 4084 Channel *c; 4085 int sock; 4086 4087 memset(&cctx, 0, sizeof(cctx)); 4088 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4089 &cctx, NULL, NULL); 4090 if (sock == -1) { 4091 channel_connect_ctx_free(&cctx); 4092 return NULL; 4093 } 4094 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4095 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4096 c->host_port = port; 4097 c->path = xstrdup(host); 4098 c->connect_ctx = cctx; 4099 4100 return c; 4101 } 4102 4103 /* 4104 * returns either the newly connected channel or the downstream channel 4105 * that needs to deal with this connection. 4106 */ 4107 Channel * 4108 channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, 4109 u_short listen_port, char *ctype, char *rname) 4110 { 4111 struct ssh_channels *sc = ssh->chanctxt; 4112 u_int i; 4113 ForwardPermission *fp; 4114 4115 for (i = 0; i < sc->num_permitted_opens; i++) { 4116 fp = &sc->permitted_opens[i]; 4117 if (open_listen_match_tcpip(fp, listen_host, listen_port, 1)) { 4118 if (fp->downstream) 4119 return fp->downstream; 4120 if (fp->port_to_connect == 0) 4121 return rdynamic_connect_prepare(ssh, 4122 ctype, rname); 4123 return connect_to(ssh, 4124 fp->host_to_connect, fp->port_to_connect, 4125 ctype, rname); 4126 } 4127 } 4128 error("WARNING: Server requests forwarding for unknown listen_port %d", 4129 listen_port); 4130 return NULL; 4131 } 4132 4133 Channel * 4134 channel_connect_by_listen_path(struct ssh *ssh, const char *path, 4135 char *ctype, char *rname) 4136 { 4137 struct ssh_channels *sc = ssh->chanctxt; 4138 u_int i; 4139 ForwardPermission *fp; 4140 4141 for (i = 0; i < sc->num_permitted_opens; i++) { 4142 fp = &sc->permitted_opens[i]; 4143 if (open_listen_match_streamlocal(fp, path)) { 4144 return connect_to(ssh, 4145 fp->host_to_connect, fp->port_to_connect, 4146 ctype, rname); 4147 } 4148 } 4149 error("WARNING: Server requests forwarding for unknown path %.100s", 4150 path); 4151 return NULL; 4152 } 4153 4154 /* Check if connecting to that port is permitted and connect. */ 4155 Channel * 4156 channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, 4157 char *ctype, char *rname, int *reason, const char **errmsg) 4158 { 4159 struct ssh_channels *sc = ssh->chanctxt; 4160 struct channel_connect cctx; 4161 Channel *c; 4162 u_int i, permit, permit_adm = 1; 4163 int sock; 4164 ForwardPermission *fp; 4165 4166 permit = sc->all_opens_permitted; 4167 if (!permit) { 4168 for (i = 0; i < sc->num_permitted_opens; i++) { 4169 fp = &sc->permitted_opens[i]; 4170 if (open_match(fp, host, port)) { 4171 permit = 1; 4172 break; 4173 } 4174 } 4175 } 4176 4177 if (sc->num_adm_permitted_opens > 0) { 4178 permit_adm = 0; 4179 for (i = 0; i < sc->num_adm_permitted_opens; i++) { 4180 fp = &sc->permitted_adm_opens[i]; 4181 if (open_match(fp, host, port)) { 4182 permit_adm = 1; 4183 break; 4184 } 4185 } 4186 } 4187 4188 if (!permit || !permit_adm) { 4189 logit("Received request to connect to host %.100s port %d, " 4190 "but the request was denied.", host, port); 4191 if (reason != NULL) 4192 *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; 4193 return NULL; 4194 } 4195 4196 memset(&cctx, 0, sizeof(cctx)); 4197 sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, 4198 &cctx, reason, errmsg); 4199 if (sock == -1) { 4200 channel_connect_ctx_free(&cctx); 4201 return NULL; 4202 } 4203 4204 c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 4205 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4206 c->host_port = port; 4207 c->path = xstrdup(host); 4208 c->connect_ctx = cctx; 4209 4210 return c; 4211 } 4212 4213 /* Check if connecting to that path is permitted and connect. */ 4214 Channel * 4215 channel_connect_to_path(struct ssh *ssh, const char *path, 4216 char *ctype, char *rname) 4217 { 4218 struct ssh_channels *sc = ssh->chanctxt; 4219 u_int i, permit, permit_adm = 1; 4220 ForwardPermission *fp; 4221 4222 permit = sc->all_opens_permitted; 4223 if (!permit) { 4224 for (i = 0; i < sc->num_permitted_opens; i++) { 4225 fp = &sc->permitted_opens[i]; 4226 if (open_match(fp, path, PORT_STREAMLOCAL)) { 4227 permit = 1; 4228 break; 4229 } 4230 } 4231 } 4232 4233 if (sc->num_adm_permitted_opens > 0) { 4234 permit_adm = 0; 4235 for (i = 0; i < sc->num_adm_permitted_opens; i++) { 4236 fp = &sc->permitted_adm_opens[i]; 4237 if (open_match(fp, path, PORT_STREAMLOCAL)) { 4238 permit_adm = 1; 4239 break; 4240 } 4241 } 4242 } 4243 4244 if (!permit || !permit_adm) { 4245 logit("Received request to connect to path %.100s, " 4246 "but the request was denied.", path); 4247 return NULL; 4248 } 4249 return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); 4250 } 4251 4252 void 4253 channel_send_window_changes(struct ssh *ssh) 4254 { 4255 struct ssh_channels *sc = ssh->chanctxt; 4256 struct winsize ws; 4257 int r; 4258 u_int i; 4259 4260 for (i = 0; i < sc->channels_alloc; i++) { 4261 if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || 4262 sc->channels[i]->type != SSH_CHANNEL_OPEN) 4263 continue; 4264 if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) < 0) 4265 continue; 4266 channel_request_start(ssh, i, "window-change", 0); 4267 if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 4268 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 4269 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 4270 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || 4271 (r = sshpkt_send(ssh)) != 0) 4272 fatal("%s: channel %u: send window-change: %s", 4273 __func__, i, ssh_err(r)); 4274 } 4275 } 4276 4277 /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ 4278 static Channel * 4279 rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) 4280 { 4281 Channel *c; 4282 int r; 4283 4284 c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, 4285 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 4286 c->host_port = 0; 4287 c->path = NULL; 4288 4289 /* 4290 * We need to open the channel before we have a FD, 4291 * so that we can get SOCKS header from peer. 4292 */ 4293 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 4294 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 4295 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 4296 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 4297 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) { 4298 fatal("%s: channel %i: confirm: %s", __func__, 4299 c->self, ssh_err(r)); 4300 } 4301 return c; 4302 } 4303 4304 /* Return CONNECTING socket to remote host:port or local socket path */ 4305 static int 4306 rdynamic_connect_finish(struct ssh *ssh, Channel *c) 4307 { 4308 struct channel_connect cctx; 4309 int sock; 4310 4311 memset(&cctx, 0, sizeof(cctx)); 4312 sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, 4313 NULL, &cctx, NULL, NULL); 4314 if (sock == -1) 4315 channel_connect_ctx_free(&cctx); 4316 else { 4317 /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ 4318 c->type = SSH_CHANNEL_RDYNAMIC_FINISH; 4319 c->connect_ctx = cctx; 4320 channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); 4321 } 4322 return sock; 4323 } 4324 4325 /* -- X11 forwarding */ 4326 4327 /* 4328 * Creates an internet domain socket for listening for X11 connections. 4329 * Returns 0 and a suitable display number for the DISPLAY variable 4330 * stored in display_numberp , or -1 if an error occurs. 4331 */ 4332 int 4333 x11_create_display_inet(struct ssh *ssh, int x11_display_offset, 4334 int x11_use_localhost, int single_connection, 4335 u_int *display_numberp, int **chanids) 4336 { 4337 Channel *nc = NULL; 4338 int display_number, sock; 4339 u_short port; 4340 struct addrinfo hints, *ai, *aitop; 4341 char strport[NI_MAXSERV]; 4342 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 4343 4344 if (chanids == NULL) 4345 return -1; 4346 4347 for (display_number = x11_display_offset; 4348 display_number < MAX_DISPLAYS; 4349 display_number++) { 4350 port = 6000 + display_number; 4351 memset(&hints, 0, sizeof(hints)); 4352 hints.ai_family = ssh->chanctxt->IPv4or6; 4353 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 4354 hints.ai_socktype = SOCK_STREAM; 4355 snprintf(strport, sizeof strport, "%d", port); 4356 if ((gaierr = getaddrinfo(NULL, strport, 4357 &hints, &aitop)) != 0) { 4358 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 4359 return -1; 4360 } 4361 for (ai = aitop; ai; ai = ai->ai_next) { 4362 if (ai->ai_family != AF_INET && 4363 ai->ai_family != AF_INET6) 4364 continue; 4365 sock = socket(ai->ai_family, ai->ai_socktype, 4366 ai->ai_protocol); 4367 if (sock < 0) { 4368 error("socket: %.100s", strerror(errno)); 4369 freeaddrinfo(aitop); 4370 return -1; 4371 } 4372 set_reuseaddr(sock); 4373 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 4374 debug2("%s: bind port %d: %.100s", __func__, 4375 port, strerror(errno)); 4376 close(sock); 4377 for (n = 0; n < num_socks; n++) 4378 close(socks[n]); 4379 num_socks = 0; 4380 break; 4381 } 4382 socks[num_socks++] = sock; 4383 if (num_socks == NUM_SOCKS) 4384 break; 4385 } 4386 freeaddrinfo(aitop); 4387 if (num_socks > 0) 4388 break; 4389 } 4390 if (display_number >= MAX_DISPLAYS) { 4391 error("Failed to allocate internet-domain X11 display socket."); 4392 return -1; 4393 } 4394 /* Start listening for connections on the socket. */ 4395 for (n = 0; n < num_socks; n++) { 4396 sock = socks[n]; 4397 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 4398 error("listen: %.100s", strerror(errno)); 4399 close(sock); 4400 return -1; 4401 } 4402 } 4403 4404 /* Allocate a channel for each socket. */ 4405 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 4406 for (n = 0; n < num_socks; n++) { 4407 sock = socks[n]; 4408 nc = channel_new(ssh, "x11 listener", 4409 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 4410 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 4411 0, "X11 inet listener", 1); 4412 nc->single_connection = single_connection; 4413 (*chanids)[n] = nc->self; 4414 } 4415 (*chanids)[n] = -1; 4416 4417 /* Return the display number for the DISPLAY environment variable. */ 4418 *display_numberp = display_number; 4419 return 0; 4420 } 4421 4422 static int 4423 connect_local_xsocket(u_int dnr) 4424 { 4425 int sock; 4426 struct sockaddr_un addr; 4427 4428 sock = socket(AF_UNIX, SOCK_STREAM, 0); 4429 if (sock < 0) 4430 error("socket: %.100s", strerror(errno)); 4431 memset(&addr, 0, sizeof(addr)); 4432 addr.sun_family = AF_UNIX; 4433 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 4434 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 4435 return sock; 4436 close(sock); 4437 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 4438 return -1; 4439 } 4440 4441 int 4442 x11_connect_display(struct ssh *ssh) 4443 { 4444 u_int display_number; 4445 const char *display; 4446 char buf[1024], *cp; 4447 struct addrinfo hints, *ai, *aitop; 4448 char strport[NI_MAXSERV]; 4449 int gaierr, sock = 0; 4450 4451 /* Try to open a socket for the local X server. */ 4452 display = getenv("DISPLAY"); 4453 if (!display) { 4454 error("DISPLAY not set."); 4455 return -1; 4456 } 4457 /* 4458 * Now we decode the value of the DISPLAY variable and make a 4459 * connection to the real X server. 4460 */ 4461 4462 /* 4463 * Check if it is a unix domain socket. Unix domain displays are in 4464 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 4465 */ 4466 if (strncmp(display, "unix:", 5) == 0 || 4467 display[0] == ':') { 4468 /* Connect to the unix domain socket. */ 4469 if (sscanf(strrchr(display, ':') + 1, "%u", 4470 &display_number) != 1) { 4471 error("Could not parse display number from DISPLAY: " 4472 "%.100s", display); 4473 return -1; 4474 } 4475 /* Create a socket. */ 4476 sock = connect_local_xsocket(display_number); 4477 if (sock < 0) 4478 return -1; 4479 4480 /* OK, we now have a connection to the display. */ 4481 return sock; 4482 } 4483 /* 4484 * Connect to an inet socket. The DISPLAY value is supposedly 4485 * hostname:d[.s], where hostname may also be numeric IP address. 4486 */ 4487 strlcpy(buf, display, sizeof(buf)); 4488 cp = strchr(buf, ':'); 4489 if (!cp) { 4490 error("Could not find ':' in DISPLAY: %.100s", display); 4491 return -1; 4492 } 4493 *cp = 0; 4494 /* 4495 * buf now contains the host name. But first we parse the 4496 * display number. 4497 */ 4498 if (sscanf(cp + 1, "%u", &display_number) != 1) { 4499 error("Could not parse display number from DISPLAY: %.100s", 4500 display); 4501 return -1; 4502 } 4503 4504 /* Look up the host address */ 4505 memset(&hints, 0, sizeof(hints)); 4506 hints.ai_family = ssh->chanctxt->IPv4or6; 4507 hints.ai_socktype = SOCK_STREAM; 4508 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 4509 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 4510 error("%.100s: unknown host. (%s)", buf, 4511 ssh_gai_strerror(gaierr)); 4512 return -1; 4513 } 4514 for (ai = aitop; ai; ai = ai->ai_next) { 4515 /* Create a socket. */ 4516 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 4517 if (sock < 0) { 4518 debug2("socket: %.100s", strerror(errno)); 4519 continue; 4520 } 4521 /* Connect it to the display. */ 4522 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 4523 debug2("connect %.100s port %u: %.100s", buf, 4524 6000 + display_number, strerror(errno)); 4525 close(sock); 4526 continue; 4527 } 4528 /* Success */ 4529 break; 4530 } 4531 freeaddrinfo(aitop); 4532 if (!ai) { 4533 error("connect %.100s port %u: %.100s", buf, 4534 6000 + display_number, strerror(errno)); 4535 return -1; 4536 } 4537 set_nodelay(sock); 4538 return sock; 4539 } 4540 4541 /* 4542 * Requests forwarding of X11 connections, generates fake authentication 4543 * data, and enables authentication spoofing. 4544 * This should be called in the client only. 4545 */ 4546 void 4547 x11_request_forwarding_with_spoofing(struct ssh *ssh, int client_session_id, 4548 const char *disp, const char *proto, const char *data, int want_reply) 4549 { 4550 struct ssh_channels *sc = ssh->chanctxt; 4551 u_int data_len = (u_int) strlen(data) / 2; 4552 u_int i, value; 4553 const char *cp; 4554 char *new_data; 4555 int r, screen_number; 4556 4557 if (sc->x11_saved_display == NULL) 4558 sc->x11_saved_display = xstrdup(disp); 4559 else if (strcmp(disp, sc->x11_saved_display) != 0) { 4560 error("x11_request_forwarding_with_spoofing: different " 4561 "$DISPLAY already forwarded"); 4562 return; 4563 } 4564 4565 cp = strchr(disp, ':'); 4566 if (cp) 4567 cp = strchr(cp, '.'); 4568 if (cp) 4569 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 4570 else 4571 screen_number = 0; 4572 4573 if (sc->x11_saved_proto == NULL) { 4574 /* Save protocol name. */ 4575 sc->x11_saved_proto = xstrdup(proto); 4576 4577 /* Extract real authentication data. */ 4578 sc->x11_saved_data = xmalloc(data_len); 4579 for (i = 0; i < data_len; i++) { 4580 if (sscanf(data + 2 * i, "%2x", &value) != 1) 4581 fatal("x11_request_forwarding: bad " 4582 "authentication data: %.100s", data); 4583 sc->x11_saved_data[i] = value; 4584 } 4585 sc->x11_saved_data_len = data_len; 4586 4587 /* Generate fake data of the same length. */ 4588 sc->x11_fake_data = xmalloc(data_len); 4589 arc4random_buf(sc->x11_fake_data, data_len); 4590 sc->x11_fake_data_len = data_len; 4591 } 4592 4593 /* Convert the fake data into hex. */ 4594 new_data = tohex(sc->x11_fake_data, data_len); 4595 4596 /* Send the request packet. */ 4597 channel_request_start(ssh, client_session_id, "x11-req", want_reply); 4598 if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ 4599 (r = sshpkt_put_cstring(ssh, proto)) != 0 || 4600 (r = sshpkt_put_cstring(ssh, new_data)) != 0 || 4601 (r = sshpkt_put_u32(ssh, screen_number)) != 0 || 4602 (r = sshpkt_send(ssh)) != 0 || 4603 (r = ssh_packet_write_wait(ssh)) != 0) 4604 fatal("%s: send x11-req: %s", __func__, ssh_err(r)); 4605 free(new_data); 4606 } 4607