1 /* $NetBSD: channels.c,v 1.7 2011/09/07 17:49:19 christos Exp $ */ 2 /* $OpenBSD: channels.c,v 1.311 2011/06/22 22:08:42 djm Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * This file contains functions for generic socket connection forwarding. 8 * There is also code for initiating connection forwarding for X11 connections, 9 * arbitrary tcp/ip connections, and the authentication agent connection. 10 * 11 * As far as I am concerned, the code I have written for this software 12 * can be used freely for any purpose. Any derived versions of this 13 * software must be clearly marked as such, and if the derived work is 14 * incompatible with the protocol description in the RFC file, it must be 15 * called by a name other than "ssh" or "Secure Shell". 16 * 17 * SSH2 support added by Markus Friedl. 18 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 19 * Copyright (c) 1999 Dug Song. All rights reserved. 20 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 32 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 34 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 41 */ 42 43 #include "includes.h" 44 __RCSID("$NetBSD: channels.c,v 1.7 2011/09/07 17:49:19 christos Exp $"); 45 #include <sys/param.h> 46 #include <sys/types.h> 47 #include <sys/ioctl.h> 48 #include <sys/un.h> 49 #include <sys/socket.h> 50 #include <sys/time.h> 51 #include <sys/queue.h> 52 53 #include <netinet/in.h> 54 #include <arpa/inet.h> 55 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <netdb.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <termios.h> 63 #include <unistd.h> 64 #include <stdarg.h> 65 66 #include "xmalloc.h" 67 #include "ssh.h" 68 #include "ssh1.h" 69 #include "ssh2.h" 70 #include "packet.h" 71 #include "log.h" 72 #include "misc.h" 73 #include "buffer.h" 74 #include "channels.h" 75 #include "compat.h" 76 #include "canohost.h" 77 #include "key.h" 78 #include "authfd.h" 79 #include "pathnames.h" 80 81 82 static int hpn_disabled = 0; 83 static int hpn_buffer_size = 2 * 1024 * 1024; 84 85 /* -- channel core */ 86 87 /* 88 * Pointer to an array containing all allocated channels. The array is 89 * dynamically extended as needed. 90 */ 91 static Channel **channels = NULL; 92 93 /* 94 * Size of the channel array. All slots of the array must always be 95 * initialized (at least the type field); unused slots set to NULL 96 */ 97 static u_int channels_alloc = 0; 98 99 /* 100 * Maximum file descriptor value used in any of the channels. This is 101 * updated in channel_new. 102 */ 103 static int channel_max_fd = 0; 104 105 106 /* -- tcp forwarding */ 107 108 /* 109 * Data structure for storing which hosts are permitted for forward requests. 110 * The local sides of any remote forwards are stored in this array to prevent 111 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 112 * network (which might be behind a firewall). 113 */ 114 typedef struct { 115 char *host_to_connect; /* Connect to 'host'. */ 116 u_short port_to_connect; /* Connect to 'port'. */ 117 u_short listen_port; /* Remote side should listen port number. */ 118 } ForwardPermission; 119 120 /* List of all permitted host/port pairs to connect by the user. */ 121 static ForwardPermission *permitted_opens = NULL; 122 123 /* List of all permitted host/port pairs to connect by the admin. */ 124 static ForwardPermission *permitted_adm_opens = NULL; 125 126 /* Number of permitted host/port pairs in the array permitted by the user. */ 127 static int num_permitted_opens = 0; 128 129 /* Number of permitted host/port pair in the array permitted by the admin. */ 130 static int num_adm_permitted_opens = 0; 131 132 /* 133 * If this is true, all opens are permitted. This is the case on the server 134 * on which we have to trust the client anyway, and the user could do 135 * anything after logging in anyway. 136 */ 137 static int all_opens_permitted = 0; 138 139 140 /* -- X11 forwarding */ 141 142 /* Maximum number of fake X11 displays to try. */ 143 #define MAX_DISPLAYS 1000 144 145 /* Saved X11 local (client) display. */ 146 static char *x11_saved_display = NULL; 147 148 /* Saved X11 authentication protocol name. */ 149 static char *x11_saved_proto = NULL; 150 151 /* Saved X11 authentication data. This is the real data. */ 152 static char *x11_saved_data = NULL; 153 static u_int x11_saved_data_len = 0; 154 155 /* 156 * Fake X11 authentication data. This is what the server will be sending us; 157 * we should replace any occurrences of this by the real data. 158 */ 159 static u_char *x11_fake_data = NULL; 160 static u_int x11_fake_data_len; 161 162 163 /* -- agent forwarding */ 164 165 #define NUM_SOCKS 10 166 167 /* AF_UNSPEC or AF_INET or AF_INET6 */ 168 static int IPv4or6 = AF_UNSPEC; 169 170 /* helper */ 171 static void port_open_helper(Channel *c, const char *rtype); 172 173 /* non-blocking connect helpers */ 174 static int connect_next(struct channel_connect *); 175 static void channel_connect_ctx_free(struct channel_connect *); 176 177 /* -- channel core */ 178 179 Channel * 180 channel_by_id(int id) 181 { 182 Channel *c; 183 184 if (id < 0 || (u_int)id >= channels_alloc) { 185 logit("channel_by_id: %d: bad id", id); 186 return NULL; 187 } 188 c = channels[id]; 189 if (c == NULL) { 190 logit("channel_by_id: %d: bad id: channel free", id); 191 return NULL; 192 } 193 return c; 194 } 195 196 /* 197 * Returns the channel if it is allowed to receive protocol messages. 198 * Private channels, like listening sockets, may not receive messages. 199 */ 200 Channel * 201 channel_lookup(int id) 202 { 203 Channel *c; 204 205 if ((c = channel_by_id(id)) == NULL) 206 return (NULL); 207 208 switch (c->type) { 209 case SSH_CHANNEL_X11_OPEN: 210 case SSH_CHANNEL_LARVAL: 211 case SSH_CHANNEL_CONNECTING: 212 case SSH_CHANNEL_DYNAMIC: 213 case SSH_CHANNEL_OPENING: 214 case SSH_CHANNEL_OPEN: 215 case SSH_CHANNEL_INPUT_DRAINING: 216 case SSH_CHANNEL_OUTPUT_DRAINING: 217 return (c); 218 } 219 logit("Non-public channel %d, type %d.", id, c->type); 220 return (NULL); 221 } 222 223 /* 224 * Register filedescriptors for a channel, used when allocating a channel or 225 * when the channel consumer/producer is ready, e.g. shell exec'd 226 */ 227 static void 228 channel_register_fds(Channel *c, int rfd, int wfd, int efd, 229 int extusage, int nonblock, int is_tty) 230 { 231 /* Update the maximum file descriptor value. */ 232 channel_max_fd = MAX(channel_max_fd, rfd); 233 channel_max_fd = MAX(channel_max_fd, wfd); 234 channel_max_fd = MAX(channel_max_fd, efd); 235 236 if (rfd != -1) 237 fcntl(rfd, F_SETFD, FD_CLOEXEC); 238 if (wfd != -1 && wfd != rfd) 239 fcntl(wfd, F_SETFD, FD_CLOEXEC); 240 if (efd != -1 && efd != rfd && efd != wfd) 241 fcntl(efd, F_SETFD, FD_CLOEXEC); 242 243 c->rfd = rfd; 244 c->wfd = wfd; 245 c->sock = (rfd == wfd) ? rfd : -1; 246 c->efd = efd; 247 c->extended_usage = extusage; 248 249 if ((c->isatty = is_tty) != 0) 250 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 251 252 /* enable nonblocking mode */ 253 if (nonblock) { 254 if (rfd != -1) 255 set_nonblock(rfd); 256 if (wfd != -1) 257 set_nonblock(wfd); 258 if (efd != -1) 259 set_nonblock(efd); 260 } 261 } 262 263 /* 264 * Allocate a new channel object and set its type and socket. This will cause 265 * remote_name to be freed. 266 */ 267 Channel * 268 channel_new(const char *ctype, int type, int rfd, int wfd, int efd, 269 u_int window, u_int maxpack, int extusage, const char *remote_name, 270 int nonblock) 271 { 272 int found; 273 u_int i; 274 Channel *c; 275 276 /* Do initial allocation if this is the first call. */ 277 if (channels_alloc == 0) { 278 channels_alloc = 10; 279 channels = xcalloc(channels_alloc, sizeof(Channel *)); 280 for (i = 0; i < channels_alloc; i++) 281 channels[i] = NULL; 282 } 283 /* Try to find a free slot where to put the new channel. */ 284 for (found = -1, i = 0; i < channels_alloc; i++) 285 if (channels[i] == NULL) { 286 /* Found a free slot. */ 287 found = (int)i; 288 break; 289 } 290 if (found < 0) { 291 /* There are no free slots. Take last+1 slot and expand the array. */ 292 found = channels_alloc; 293 if (channels_alloc > 10000) 294 fatal("channel_new: internal error: channels_alloc %d " 295 "too big.", channels_alloc); 296 channels = xrealloc(channels, channels_alloc + 10, 297 sizeof(Channel *)); 298 channels_alloc += 10; 299 debug2("channel: expanding %d", channels_alloc); 300 for (i = found; i < channels_alloc; i++) 301 channels[i] = NULL; 302 } 303 /* Initialize and return new channel. */ 304 c = channels[found] = xcalloc(1, sizeof(Channel)); 305 buffer_init(&c->input); 306 buffer_init(&c->output); 307 buffer_init(&c->extended); 308 c->path = NULL; 309 c->ostate = CHAN_OUTPUT_OPEN; 310 c->istate = CHAN_INPUT_OPEN; 311 c->flags = 0; 312 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0); 313 c->self = found; 314 c->type = type; 315 c->ctype = __UNCONST(ctype); 316 c->local_window = window; 317 c->local_window_max = window; 318 c->local_consumed = 0; 319 c->local_maxpacket = maxpack; 320 c->dynamic_window = 0; 321 c->remote_id = -1; 322 c->remote_name = xstrdup(remote_name); 323 c->remote_window = 0; 324 c->remote_maxpacket = 0; 325 c->force_drain = 0; 326 c->single_connection = 0; 327 c->detach_user = NULL; 328 c->detach_close = 0; 329 c->open_confirm = NULL; 330 c->open_confirm_ctx = NULL; 331 c->input_filter = NULL; 332 c->output_filter = NULL; 333 c->filter_ctx = NULL; 334 c->filter_cleanup = NULL; 335 c->ctl_chan = -1; 336 c->mux_rcb = NULL; 337 c->mux_ctx = NULL; 338 c->mux_pause = 0; 339 c->delayed = 1; /* prevent call to channel_post handler */ 340 TAILQ_INIT(&c->status_confirms); 341 debug("channel %d: new [%s]", found, remote_name); 342 return c; 343 } 344 345 static int 346 channel_find_maxfd(void) 347 { 348 u_int i; 349 int max = 0; 350 Channel *c; 351 352 for (i = 0; i < channels_alloc; i++) { 353 c = channels[i]; 354 if (c != NULL) { 355 max = MAX(max, c->rfd); 356 max = MAX(max, c->wfd); 357 max = MAX(max, c->efd); 358 } 359 } 360 return max; 361 } 362 363 int 364 channel_close_fd(int *fdp) 365 { 366 int ret = 0, fd = *fdp; 367 368 if (fd != -1) { 369 ret = close(fd); 370 *fdp = -1; 371 if (fd == channel_max_fd) 372 channel_max_fd = channel_find_maxfd(); 373 } 374 return ret; 375 } 376 377 /* Close all channel fd/socket. */ 378 static void 379 channel_close_fds(Channel *c) 380 { 381 channel_close_fd(&c->sock); 382 channel_close_fd(&c->rfd); 383 channel_close_fd(&c->wfd); 384 channel_close_fd(&c->efd); 385 } 386 387 /* Free the channel and close its fd/socket. */ 388 void 389 channel_free(Channel *c) 390 { 391 char *s; 392 u_int i, n; 393 struct channel_confirm *cc; 394 395 for (n = 0, i = 0; i < channels_alloc; i++) 396 if (channels[i]) 397 n++; 398 debug("channel %d: free: %s, nchannels %u", c->self, 399 c->remote_name ? c->remote_name : "???", n); 400 401 s = channel_open_message(); 402 debug3("channel %d: status: %s", c->self, s); 403 xfree(s); 404 405 if (c->sock != -1) 406 shutdown(c->sock, SHUT_RDWR); 407 channel_close_fds(c); 408 buffer_free(&c->input); 409 buffer_free(&c->output); 410 buffer_free(&c->extended); 411 if (c->remote_name) { 412 xfree(c->remote_name); 413 c->remote_name = NULL; 414 } 415 if (c->path) { 416 xfree(c->path); 417 c->path = NULL; 418 } 419 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 420 if (cc->abandon_cb != NULL) 421 cc->abandon_cb(c, cc->ctx); 422 TAILQ_REMOVE(&c->status_confirms, cc, entry); 423 bzero(cc, sizeof(*cc)); 424 xfree(cc); 425 } 426 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 427 c->filter_cleanup(c->self, c->filter_ctx); 428 channels[c->self] = NULL; 429 xfree(c); 430 } 431 432 void 433 channel_free_all(void) 434 { 435 u_int i; 436 437 for (i = 0; i < channels_alloc; i++) 438 if (channels[i] != NULL) 439 channel_free(channels[i]); 440 } 441 442 /* 443 * Closes the sockets/fds of all channels. This is used to close extra file 444 * descriptors after a fork. 445 */ 446 void 447 channel_close_all(void) 448 { 449 u_int i; 450 451 for (i = 0; i < channels_alloc; i++) 452 if (channels[i] != NULL) 453 channel_close_fds(channels[i]); 454 } 455 456 /* 457 * Stop listening to channels. 458 */ 459 void 460 channel_stop_listening(void) 461 { 462 u_int i; 463 Channel *c; 464 465 for (i = 0; i < channels_alloc; i++) { 466 c = channels[i]; 467 if (c != NULL) { 468 switch (c->type) { 469 case SSH_CHANNEL_AUTH_SOCKET: 470 case SSH_CHANNEL_PORT_LISTENER: 471 case SSH_CHANNEL_RPORT_LISTENER: 472 case SSH_CHANNEL_X11_LISTENER: 473 channel_close_fd(&c->sock); 474 channel_free(c); 475 break; 476 } 477 } 478 } 479 } 480 481 /* 482 * Returns true if no channel has too much buffered data, and false if one or 483 * more channel is overfull. 484 */ 485 int 486 channel_not_very_much_buffered_data(void) 487 { 488 u_int i; 489 Channel *c; 490 491 for (i = 0; i < channels_alloc; i++) { 492 c = channels[i]; 493 if (c != NULL && c->type == SSH_CHANNEL_OPEN) { 494 #if 0 495 if (!compat20 && 496 buffer_len(&c->input) > packet_get_maxsize()) { 497 debug2("channel %d: big input buffer %d", 498 c->self, buffer_len(&c->input)); 499 return 0; 500 } 501 #endif 502 if (buffer_len(&c->output) > packet_get_maxsize()) { 503 debug2("channel %d: big output buffer %u > %u", 504 c->self, buffer_len(&c->output), 505 packet_get_maxsize()); 506 return 0; 507 } 508 } 509 } 510 return 1; 511 } 512 513 /* Returns true if any channel is still open. */ 514 int 515 channel_still_open(void) 516 { 517 u_int i; 518 Channel *c; 519 520 for (i = 0; i < channels_alloc; i++) { 521 c = channels[i]; 522 if (c == NULL) 523 continue; 524 switch (c->type) { 525 case SSH_CHANNEL_X11_LISTENER: 526 case SSH_CHANNEL_PORT_LISTENER: 527 case SSH_CHANNEL_RPORT_LISTENER: 528 case SSH_CHANNEL_MUX_LISTENER: 529 case SSH_CHANNEL_CLOSED: 530 case SSH_CHANNEL_AUTH_SOCKET: 531 case SSH_CHANNEL_DYNAMIC: 532 case SSH_CHANNEL_CONNECTING: 533 case SSH_CHANNEL_ZOMBIE: 534 continue; 535 case SSH_CHANNEL_LARVAL: 536 if (!compat20) 537 fatal("cannot happen: SSH_CHANNEL_LARVAL"); 538 continue; 539 case SSH_CHANNEL_OPENING: 540 case SSH_CHANNEL_OPEN: 541 case SSH_CHANNEL_X11_OPEN: 542 case SSH_CHANNEL_MUX_CLIENT: 543 return 1; 544 case SSH_CHANNEL_INPUT_DRAINING: 545 case SSH_CHANNEL_OUTPUT_DRAINING: 546 if (!compat13) 547 fatal("cannot happen: OUT_DRAIN"); 548 return 1; 549 default: 550 fatal("channel_still_open: bad channel type %d", c->type); 551 /* NOTREACHED */ 552 } 553 } 554 return 0; 555 } 556 557 /* Returns the id of an open channel suitable for keepaliving */ 558 int 559 channel_find_open(void) 560 { 561 u_int i; 562 Channel *c; 563 564 for (i = 0; i < channels_alloc; i++) { 565 c = channels[i]; 566 if (c == NULL || c->remote_id < 0) 567 continue; 568 switch (c->type) { 569 case SSH_CHANNEL_CLOSED: 570 case SSH_CHANNEL_DYNAMIC: 571 case SSH_CHANNEL_X11_LISTENER: 572 case SSH_CHANNEL_PORT_LISTENER: 573 case SSH_CHANNEL_RPORT_LISTENER: 574 case SSH_CHANNEL_MUX_LISTENER: 575 case SSH_CHANNEL_MUX_CLIENT: 576 case SSH_CHANNEL_OPENING: 577 case SSH_CHANNEL_CONNECTING: 578 case SSH_CHANNEL_ZOMBIE: 579 continue; 580 case SSH_CHANNEL_LARVAL: 581 case SSH_CHANNEL_AUTH_SOCKET: 582 case SSH_CHANNEL_OPEN: 583 case SSH_CHANNEL_X11_OPEN: 584 return i; 585 case SSH_CHANNEL_INPUT_DRAINING: 586 case SSH_CHANNEL_OUTPUT_DRAINING: 587 if (!compat13) 588 fatal("cannot happen: OUT_DRAIN"); 589 return i; 590 default: 591 fatal("channel_find_open: bad channel type %d", c->type); 592 /* NOTREACHED */ 593 } 594 } 595 return -1; 596 } 597 598 599 /* 600 * Returns a message describing the currently open forwarded connections, 601 * suitable for sending to the client. The message contains crlf pairs for 602 * newlines. 603 */ 604 char * 605 channel_open_message(void) 606 { 607 Buffer buffer; 608 Channel *c; 609 char buf[1024], *cp; 610 u_int i; 611 612 buffer_init(&buffer); 613 snprintf(buf, sizeof buf, "The following connections are open:\r\n"); 614 buffer_append(&buffer, buf, strlen(buf)); 615 for (i = 0; i < channels_alloc; i++) { 616 c = channels[i]; 617 if (c == NULL) 618 continue; 619 switch (c->type) { 620 case SSH_CHANNEL_X11_LISTENER: 621 case SSH_CHANNEL_PORT_LISTENER: 622 case SSH_CHANNEL_RPORT_LISTENER: 623 case SSH_CHANNEL_CLOSED: 624 case SSH_CHANNEL_AUTH_SOCKET: 625 case SSH_CHANNEL_ZOMBIE: 626 case SSH_CHANNEL_MUX_CLIENT: 627 case SSH_CHANNEL_MUX_LISTENER: 628 continue; 629 case SSH_CHANNEL_LARVAL: 630 case SSH_CHANNEL_OPENING: 631 case SSH_CHANNEL_CONNECTING: 632 case SSH_CHANNEL_DYNAMIC: 633 case SSH_CHANNEL_OPEN: 634 case SSH_CHANNEL_X11_OPEN: 635 case SSH_CHANNEL_INPUT_DRAINING: 636 case SSH_CHANNEL_OUTPUT_DRAINING: 637 snprintf(buf, sizeof buf, 638 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n", 639 c->self, c->remote_name, 640 c->type, c->remote_id, 641 c->istate, buffer_len(&c->input), 642 c->ostate, buffer_len(&c->output), 643 c->rfd, c->wfd, c->ctl_chan); 644 buffer_append(&buffer, buf, strlen(buf)); 645 continue; 646 default: 647 fatal("channel_open_message: bad channel type %d", c->type); 648 /* NOTREACHED */ 649 } 650 } 651 buffer_append(&buffer, "\0", 1); 652 cp = xstrdup(buffer_ptr(&buffer)); 653 buffer_free(&buffer); 654 return cp; 655 } 656 657 void 658 channel_send_open(int id) 659 { 660 Channel *c = channel_lookup(id); 661 662 if (c == NULL) { 663 logit("channel_send_open: %d: bad id", id); 664 return; 665 } 666 debug2("channel %d: send open", id); 667 packet_start(SSH2_MSG_CHANNEL_OPEN); 668 packet_put_cstring(c->ctype); 669 packet_put_int(c->self); 670 packet_put_int(c->local_window); 671 packet_put_int(c->local_maxpacket); 672 packet_send(); 673 } 674 675 void 676 channel_request_start(int id, const char *service, int wantconfirm) 677 { 678 Channel *c = channel_lookup(id); 679 680 if (c == NULL) { 681 logit("channel_request_start: %d: unknown channel id", id); 682 return; 683 } 684 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 685 packet_start(SSH2_MSG_CHANNEL_REQUEST); 686 packet_put_int(c->remote_id); 687 packet_put_cstring(service); 688 packet_put_char(wantconfirm); 689 } 690 691 void 692 channel_register_status_confirm(int id, channel_confirm_cb *cb, 693 channel_confirm_abandon_cb *abandon_cb, void *ctx) 694 { 695 struct channel_confirm *cc; 696 Channel *c; 697 698 if ((c = channel_lookup(id)) == NULL) 699 fatal("channel_register_expect: %d: bad id", id); 700 701 cc = xmalloc(sizeof(*cc)); 702 cc->cb = cb; 703 cc->abandon_cb = abandon_cb; 704 cc->ctx = ctx; 705 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 706 } 707 708 void 709 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx) 710 { 711 Channel *c = channel_lookup(id); 712 713 if (c == NULL) { 714 logit("channel_register_open_confirm: %d: bad id", id); 715 return; 716 } 717 c->open_confirm = fn; 718 c->open_confirm_ctx = ctx; 719 } 720 721 void 722 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close) 723 { 724 Channel *c = channel_by_id(id); 725 726 if (c == NULL) { 727 logit("channel_register_cleanup: %d: bad id", id); 728 return; 729 } 730 c->detach_user = fn; 731 c->detach_close = do_close; 732 } 733 734 void 735 channel_cancel_cleanup(int id) 736 { 737 Channel *c = channel_by_id(id); 738 739 if (c == NULL) { 740 logit("channel_cancel_cleanup: %d: bad id", id); 741 return; 742 } 743 c->detach_user = NULL; 744 c->detach_close = 0; 745 } 746 747 void 748 channel_register_filter(int id, channel_infilter_fn *ifn, 749 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 750 { 751 Channel *c = channel_lookup(id); 752 753 if (c == NULL) { 754 logit("channel_register_filter: %d: bad id", id); 755 return; 756 } 757 c->input_filter = ifn; 758 c->output_filter = ofn; 759 c->filter_ctx = ctx; 760 c->filter_cleanup = cfn; 761 } 762 763 void 764 channel_set_fds(int id, int rfd, int wfd, int efd, 765 int extusage, int nonblock, int is_tty, u_int window_max) 766 { 767 Channel *c = channel_lookup(id); 768 769 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 770 fatal("channel_activate for non-larval channel %d.", id); 771 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty); 772 c->type = SSH_CHANNEL_OPEN; 773 c->local_window = c->local_window_max = window_max; 774 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 775 packet_put_int(c->remote_id); 776 packet_put_int(c->local_window); 777 packet_send(); 778 } 779 780 /* 781 * 'channel_pre*' are called just before select() to add any bits relevant to 782 * channels in the select bitmasks. 783 */ 784 /* 785 * 'channel_post*': perform any appropriate operations for channels which 786 * have events pending. 787 */ 788 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset); 789 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; 790 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; 791 792 /* ARGSUSED */ 793 static void 794 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset) 795 { 796 FD_SET(c->sock, readset); 797 } 798 799 /* ARGSUSED */ 800 static void 801 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset) 802 { 803 debug3("channel %d: waiting for connection", c->self); 804 FD_SET(c->sock, writeset); 805 } 806 807 static 808 int channel_tcpwinsz(void) 809 { 810 u_int32_t tcpwinsz = 0; 811 socklen_t optsz = sizeof(tcpwinsz); 812 int ret = -1; 813 814 /* if we aren't on a socket return 128KB*/ 815 if(!packet_connection_is_on_socket()) 816 return(128*1024); 817 ret = getsockopt(packet_get_connection_in(), 818 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz); 819 /* return no more than 64MB */ 820 if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN) 821 tcpwinsz = BUFFER_MAX_LEN_HPN; 822 debug2("tcpwinsz: %d for connection: %d", tcpwinsz, 823 packet_get_connection_in()); 824 return(tcpwinsz); 825 } 826 827 static void 828 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset) 829 { 830 if (buffer_len(&c->input) < packet_get_maxsize()) 831 FD_SET(c->sock, readset); 832 if (buffer_len(&c->output) > 0) 833 FD_SET(c->sock, writeset); 834 } 835 836 static void 837 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset) 838 { 839 u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); 840 841 /* check buffer limits */ 842 if ((!c->tcpwinsz) || (c->dynamic_window > 0)) 843 c->tcpwinsz = channel_tcpwinsz(); 844 845 limit = MIN(limit, 2 * c->tcpwinsz); 846 847 if (c->istate == CHAN_INPUT_OPEN && 848 limit > 0 && 849 buffer_len(&c->input) < limit && 850 buffer_check_alloc(&c->input, CHAN_RBUF)) 851 FD_SET(c->rfd, readset); 852 if (c->ostate == CHAN_OUTPUT_OPEN || 853 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 854 if (buffer_len(&c->output) > 0) { 855 FD_SET(c->wfd, writeset); 856 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 857 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 858 debug2("channel %d: obuf_empty delayed efd %d/(%d)", 859 c->self, c->efd, buffer_len(&c->extended)); 860 else 861 chan_obuf_empty(c); 862 } 863 } 864 /** XXX check close conditions, too */ 865 if (compat20 && c->efd != -1 && 866 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) { 867 if (c->extended_usage == CHAN_EXTENDED_WRITE && 868 buffer_len(&c->extended) > 0) 869 FD_SET(c->efd, writeset); 870 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 871 (c->extended_usage == CHAN_EXTENDED_READ || 872 c->extended_usage == CHAN_EXTENDED_IGNORE) && 873 buffer_len(&c->extended) < c->remote_window) 874 FD_SET(c->efd, readset); 875 } 876 /* XXX: What about efd? races? */ 877 } 878 879 /* ARGSUSED */ 880 static void 881 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset) 882 { 883 if (buffer_len(&c->input) == 0) { 884 packet_start(SSH_MSG_CHANNEL_CLOSE); 885 packet_put_int(c->remote_id); 886 packet_send(); 887 c->type = SSH_CHANNEL_CLOSED; 888 debug2("channel %d: closing after input drain.", c->self); 889 } 890 } 891 892 /* ARGSUSED */ 893 static void 894 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset) 895 { 896 if (buffer_len(&c->output) == 0) 897 chan_mark_dead(c); 898 else 899 FD_SET(c->sock, writeset); 900 } 901 902 /* 903 * This is a special state for X11 authentication spoofing. An opened X11 904 * connection (when authentication spoofing is being done) remains in this 905 * state until the first packet has been completely read. The authentication 906 * data in that packet is then substituted by the real data if it matches the 907 * fake data, and the channel is put into normal mode. 908 * XXX All this happens at the client side. 909 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 910 */ 911 static int 912 x11_open_helper(Buffer *b) 913 { 914 u_char *ucp; 915 u_int proto_len, data_len; 916 917 /* Check if the fixed size part of the packet is in buffer. */ 918 if (buffer_len(b) < 12) 919 return 0; 920 921 /* Parse the lengths of variable-length fields. */ 922 ucp = buffer_ptr(b); 923 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 924 proto_len = 256 * ucp[6] + ucp[7]; 925 data_len = 256 * ucp[8] + ucp[9]; 926 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 927 proto_len = ucp[6] + 256 * ucp[7]; 928 data_len = ucp[8] + 256 * ucp[9]; 929 } else { 930 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 931 ucp[0]); 932 return -1; 933 } 934 935 /* Check if the whole packet is in buffer. */ 936 if (buffer_len(b) < 937 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 938 return 0; 939 940 /* Check if authentication protocol matches. */ 941 if (proto_len != strlen(x11_saved_proto) || 942 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { 943 debug2("X11 connection uses different authentication protocol."); 944 return -1; 945 } 946 /* Check if authentication data matches our fake data. */ 947 if (data_len != x11_fake_data_len || 948 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 949 x11_fake_data, x11_fake_data_len) != 0) { 950 debug2("X11 auth data does not match fake data."); 951 return -1; 952 } 953 /* Check fake data length */ 954 if (x11_fake_data_len != x11_saved_data_len) { 955 error("X11 fake_data_len %d != saved_data_len %d", 956 x11_fake_data_len, x11_saved_data_len); 957 return -1; 958 } 959 /* 960 * Received authentication protocol and data match 961 * our fake data. Substitute the fake data with real 962 * data. 963 */ 964 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 965 x11_saved_data, x11_saved_data_len); 966 return 1; 967 } 968 969 static void 970 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset) 971 { 972 int ret = x11_open_helper(&c->output); 973 974 if (ret == 1) { 975 /* Start normal processing for the channel. */ 976 c->type = SSH_CHANNEL_OPEN; 977 channel_pre_open_13(c, readset, writeset); 978 } else if (ret == -1) { 979 /* 980 * We have received an X11 connection that has bad 981 * authentication information. 982 */ 983 logit("X11 connection rejected because of wrong authentication."); 984 buffer_clear(&c->input); 985 buffer_clear(&c->output); 986 channel_close_fd(&c->sock); 987 c->sock = -1; 988 c->type = SSH_CHANNEL_CLOSED; 989 packet_start(SSH_MSG_CHANNEL_CLOSE); 990 packet_put_int(c->remote_id); 991 packet_send(); 992 } 993 } 994 995 static void 996 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset) 997 { 998 int ret = x11_open_helper(&c->output); 999 1000 /* c->force_drain = 1; */ 1001 1002 if (ret == 1) { 1003 c->type = SSH_CHANNEL_OPEN; 1004 channel_pre_open(c, readset, writeset); 1005 } else if (ret == -1) { 1006 logit("X11 connection rejected because of wrong authentication."); 1007 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); 1008 chan_read_failed(c); 1009 buffer_clear(&c->input); 1010 chan_ibuf_empty(c); 1011 buffer_clear(&c->output); 1012 /* for proto v1, the peer will send an IEOF */ 1013 if (compat20) 1014 chan_write_failed(c); 1015 else 1016 c->type = SSH_CHANNEL_OPEN; 1017 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1018 } 1019 } 1020 1021 static void 1022 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1023 { 1024 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1025 buffer_check_alloc(&c->input, CHAN_RBUF)) 1026 FD_SET(c->rfd, readset); 1027 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1028 /* clear buffer immediately (discard any partial packet) */ 1029 buffer_clear(&c->input); 1030 chan_ibuf_empty(c); 1031 /* Start output drain. XXX just kill chan? */ 1032 chan_rcvd_oclose(c); 1033 } 1034 if (c->ostate == CHAN_OUTPUT_OPEN || 1035 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1036 if (buffer_len(&c->output) > 0) 1037 FD_SET(c->wfd, writeset); 1038 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1039 chan_obuf_empty(c); 1040 } 1041 } 1042 1043 /* try to decode a socks4 header */ 1044 /* ARGSUSED */ 1045 static int 1046 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset) 1047 { 1048 char *p, *host; 1049 u_int len, have, i, found, need; 1050 char username[256]; 1051 struct { 1052 u_int8_t version; 1053 u_int8_t command; 1054 u_int16_t dest_port; 1055 struct in_addr dest_addr; 1056 } s4_req, s4_rsp; 1057 1058 debug2("channel %d: decode socks4", c->self); 1059 1060 have = buffer_len(&c->input); 1061 len = sizeof(s4_req); 1062 if (have < len) 1063 return 0; 1064 p = buffer_ptr(&c->input); 1065 1066 need = 1; 1067 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1068 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1069 debug2("channel %d: socks4a request", c->self); 1070 /* ... and needs an extra string (the hostname) */ 1071 need = 2; 1072 } 1073 /* Check for terminating NUL on the string(s) */ 1074 for (found = 0, i = len; i < have; i++) { 1075 if (p[i] == '\0') { 1076 found++; 1077 if (found == need) 1078 break; 1079 } 1080 if (i > 1024) { 1081 /* the peer is probably sending garbage */ 1082 debug("channel %d: decode socks4: too long", 1083 c->self); 1084 return -1; 1085 } 1086 } 1087 if (found < need) 1088 return 0; 1089 buffer_get(&c->input, (char *)&s4_req.version, 1); 1090 buffer_get(&c->input, (char *)&s4_req.command, 1); 1091 buffer_get(&c->input, (char *)&s4_req.dest_port, 2); 1092 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); 1093 have = buffer_len(&c->input); 1094 p = buffer_ptr(&c->input); 1095 len = strlen(p); 1096 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1097 len++; /* trailing '\0' */ 1098 if (len > have) 1099 fatal("channel %d: decode socks4: len %d > have %d", 1100 c->self, len, have); 1101 strlcpy(username, p, sizeof(username)); 1102 buffer_consume(&c->input, len); 1103 1104 if (c->path != NULL) { 1105 xfree(c->path); 1106 c->path = NULL; 1107 } 1108 if (need == 1) { /* SOCKS4: one string */ 1109 host = inet_ntoa(s4_req.dest_addr); 1110 c->path = xstrdup(host); 1111 } else { /* SOCKS4A: two strings */ 1112 have = buffer_len(&c->input); 1113 p = buffer_ptr(&c->input); 1114 len = strlen(p); 1115 debug2("channel %d: decode socks4a: host %s/%d", 1116 c->self, p, len); 1117 len++; /* trailing '\0' */ 1118 if (len > have) 1119 fatal("channel %d: decode socks4a: len %d > have %d", 1120 c->self, len, have); 1121 if (len > NI_MAXHOST) { 1122 error("channel %d: hostname \"%.100s\" too long", 1123 c->self, p); 1124 return -1; 1125 } 1126 c->path = xstrdup(p); 1127 buffer_consume(&c->input, len); 1128 } 1129 c->host_port = ntohs(s4_req.dest_port); 1130 1131 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1132 c->self, c->path, c->host_port, s4_req.command); 1133 1134 if (s4_req.command != 1) { 1135 debug("channel %d: cannot handle: %s cn %d", 1136 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1137 return -1; 1138 } 1139 s4_rsp.version = 0; /* vn: 0 for reply */ 1140 s4_rsp.command = 90; /* cd: req granted */ 1141 s4_rsp.dest_port = 0; /* ignored */ 1142 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1143 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp)); 1144 return 1; 1145 } 1146 1147 /* try to decode a socks5 header */ 1148 #define SSH_SOCKS5_AUTHDONE 0x1000 1149 #define SSH_SOCKS5_NOAUTH 0x00 1150 #define SSH_SOCKS5_IPV4 0x01 1151 #define SSH_SOCKS5_DOMAIN 0x03 1152 #define SSH_SOCKS5_IPV6 0x04 1153 #define SSH_SOCKS5_CONNECT 0x01 1154 #define SSH_SOCKS5_SUCCESS 0x00 1155 1156 /* ARGSUSED */ 1157 static int 1158 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset) 1159 { 1160 struct { 1161 u_int8_t version; 1162 u_int8_t command; 1163 u_int8_t reserved; 1164 u_int8_t atyp; 1165 } s5_req, s5_rsp; 1166 u_int16_t dest_port; 1167 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1168 u_int have, need, i, found, nmethods, addrlen, af; 1169 1170 debug2("channel %d: decode socks5", c->self); 1171 p = buffer_ptr(&c->input); 1172 if (p[0] != 0x05) 1173 return -1; 1174 have = buffer_len(&c->input); 1175 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1176 /* format: ver | nmethods | methods */ 1177 if (have < 2) 1178 return 0; 1179 nmethods = p[1]; 1180 if (have < nmethods + 2) 1181 return 0; 1182 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1183 for (found = 0, i = 2; i < nmethods + 2; i++) { 1184 if (p[i] == SSH_SOCKS5_NOAUTH) { 1185 found = 1; 1186 break; 1187 } 1188 } 1189 if (!found) { 1190 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1191 c->self); 1192 return -1; 1193 } 1194 buffer_consume(&c->input, nmethods + 2); 1195 buffer_put_char(&c->output, 0x05); /* version */ 1196 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ 1197 FD_SET(c->sock, writeset); 1198 c->flags |= SSH_SOCKS5_AUTHDONE; 1199 debug2("channel %d: socks5 auth done", c->self); 1200 return 0; /* need more */ 1201 } 1202 debug2("channel %d: socks5 post auth", c->self); 1203 if (have < sizeof(s5_req)+1) 1204 return 0; /* need more */ 1205 memcpy(&s5_req, p, sizeof(s5_req)); 1206 if (s5_req.version != 0x05 || 1207 s5_req.command != SSH_SOCKS5_CONNECT || 1208 s5_req.reserved != 0x00) { 1209 debug2("channel %d: only socks5 connect supported", c->self); 1210 return -1; 1211 } 1212 switch (s5_req.atyp){ 1213 case SSH_SOCKS5_IPV4: 1214 addrlen = 4; 1215 af = AF_INET; 1216 break; 1217 case SSH_SOCKS5_DOMAIN: 1218 addrlen = p[sizeof(s5_req)]; 1219 af = -1; 1220 break; 1221 case SSH_SOCKS5_IPV6: 1222 addrlen = 16; 1223 af = AF_INET6; 1224 break; 1225 default: 1226 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1227 return -1; 1228 } 1229 need = sizeof(s5_req) + addrlen + 2; 1230 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1231 need++; 1232 if (have < need) 1233 return 0; 1234 buffer_consume(&c->input, sizeof(s5_req)); 1235 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1236 buffer_consume(&c->input, 1); /* host string length */ 1237 buffer_get(&c->input, (char *)&dest_addr, addrlen); 1238 buffer_get(&c->input, (char *)&dest_port, 2); 1239 dest_addr[addrlen] = '\0'; 1240 if (c->path != NULL) { 1241 xfree(c->path); 1242 c->path = NULL; 1243 } 1244 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1245 if (addrlen >= NI_MAXHOST) { 1246 error("channel %d: dynamic request: socks5 hostname " 1247 "\"%.100s\" too long", c->self, dest_addr); 1248 return -1; 1249 } 1250 c->path = xstrdup(dest_addr); 1251 } else { 1252 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1253 return -1; 1254 c->path = xstrdup(ntop); 1255 } 1256 c->host_port = ntohs(dest_port); 1257 1258 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1259 c->self, c->path, c->host_port, s5_req.command); 1260 1261 s5_rsp.version = 0x05; 1262 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1263 s5_rsp.reserved = 0; /* ignored */ 1264 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1265 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY; 1266 dest_port = 0; /* ignored */ 1267 1268 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp)); 1269 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr)); 1270 buffer_append(&c->output, &dest_port, sizeof(dest_port)); 1271 return 1; 1272 } 1273 1274 Channel * 1275 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect, 1276 int in, int out) 1277 { 1278 Channel *c; 1279 1280 debug("channel_connect_stdio_fwd %s:%d", host_to_connect, 1281 port_to_connect); 1282 1283 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out, 1284 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1285 0, "stdio-forward", /*nonblock*/0); 1286 1287 c->path = xstrdup(host_to_connect); 1288 c->host_port = port_to_connect; 1289 c->listening_port = 0; 1290 c->force_drain = 1; 1291 1292 channel_register_fds(c, in, out, -1, 0, 1, 0); 1293 port_open_helper(c, "direct-tcpip"); 1294 1295 return c; 1296 } 1297 1298 /* dynamic port forwarding */ 1299 static void 1300 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset) 1301 { 1302 u_char *p; 1303 u_int have; 1304 int ret; 1305 1306 have = buffer_len(&c->input); 1307 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1308 /* buffer_dump(&c->input); */ 1309 /* check if the fixed size part of the packet is in buffer. */ 1310 if (have < 3) { 1311 /* need more */ 1312 FD_SET(c->sock, readset); 1313 return; 1314 } 1315 /* try to guess the protocol */ 1316 p = buffer_ptr(&c->input); 1317 switch (p[0]) { 1318 case 0x04: 1319 ret = channel_decode_socks4(c, readset, writeset); 1320 break; 1321 case 0x05: 1322 ret = channel_decode_socks5(c, readset, writeset); 1323 break; 1324 default: 1325 ret = -1; 1326 break; 1327 } 1328 if (ret < 0) { 1329 chan_mark_dead(c); 1330 } else if (ret == 0) { 1331 debug2("channel %d: pre_dynamic: need more", c->self); 1332 /* need more */ 1333 FD_SET(c->sock, readset); 1334 } else { 1335 /* switch to the next state */ 1336 c->type = SSH_CHANNEL_OPENING; 1337 port_open_helper(c, "direct-tcpip"); 1338 } 1339 } 1340 1341 /* This is our fake X11 server socket. */ 1342 /* ARGSUSED */ 1343 static void 1344 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset) 1345 { 1346 Channel *nc; 1347 struct sockaddr_storage addr; 1348 int newsock; 1349 socklen_t addrlen; 1350 char buf[16384], *remote_ipaddr; 1351 int remote_port; 1352 1353 if (FD_ISSET(c->sock, readset)) { 1354 debug("X11 connection requested."); 1355 addrlen = sizeof(addr); 1356 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1357 if (c->single_connection) { 1358 debug2("single_connection: closing X11 listener."); 1359 channel_close_fd(&c->sock); 1360 chan_mark_dead(c); 1361 } 1362 if (newsock < 0) { 1363 error("accept: %.100s", strerror(errno)); 1364 return; 1365 } 1366 set_nodelay(newsock); 1367 remote_ipaddr = get_peer_ipaddr(newsock); 1368 remote_port = get_peer_port(newsock); 1369 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1370 remote_ipaddr, remote_port); 1371 1372 nc = channel_new("accepted x11 socket", 1373 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1374 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1375 if (compat20) { 1376 packet_start(SSH2_MSG_CHANNEL_OPEN); 1377 packet_put_cstring("x11"); 1378 packet_put_int(nc->self); 1379 packet_put_int(nc->local_window_max); 1380 packet_put_int(nc->local_maxpacket); 1381 /* originator ipaddr and port */ 1382 packet_put_cstring(remote_ipaddr); 1383 if (datafellows & SSH_BUG_X11FWD) { 1384 debug2("ssh2 x11 bug compat mode"); 1385 } else { 1386 packet_put_int(remote_port); 1387 } 1388 packet_send(); 1389 } else { 1390 packet_start(SSH_SMSG_X11_OPEN); 1391 packet_put_int(nc->self); 1392 if (packet_get_protocol_flags() & 1393 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1394 packet_put_cstring(buf); 1395 packet_send(); 1396 } 1397 xfree(remote_ipaddr); 1398 } 1399 } 1400 1401 static void 1402 port_open_helper(Channel *c, const char *rtype) 1403 { 1404 int direct; 1405 char buf[1024]; 1406 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1407 int remote_port = get_peer_port(c->sock); 1408 1409 if (remote_port == -1) { 1410 /* Fake addr/port to appease peers that validate it (Tectia) */ 1411 xfree(remote_ipaddr); 1412 remote_ipaddr = xstrdup("127.0.0.1"); 1413 remote_port = 65535; 1414 } 1415 1416 direct = (strcmp(rtype, "direct-tcpip") == 0); 1417 1418 snprintf(buf, sizeof buf, 1419 "%s: listening port %d for %.100s port %d, " 1420 "connect from %.200s port %d", 1421 rtype, c->listening_port, c->path, c->host_port, 1422 remote_ipaddr, remote_port); 1423 1424 xfree(c->remote_name); 1425 c->remote_name = xstrdup(buf); 1426 1427 if (compat20) { 1428 packet_start(SSH2_MSG_CHANNEL_OPEN); 1429 packet_put_cstring(rtype); 1430 packet_put_int(c->self); 1431 packet_put_int(c->local_window_max); 1432 packet_put_int(c->local_maxpacket); 1433 if (direct) { 1434 /* target host, port */ 1435 packet_put_cstring(c->path); 1436 packet_put_int(c->host_port); 1437 } else { 1438 /* listen address, port */ 1439 packet_put_cstring(c->path); 1440 packet_put_int(c->listening_port); 1441 } 1442 /* originator host and port */ 1443 packet_put_cstring(remote_ipaddr); 1444 packet_put_int((u_int)remote_port); 1445 packet_send(); 1446 } else { 1447 packet_start(SSH_MSG_PORT_OPEN); 1448 packet_put_int(c->self); 1449 packet_put_cstring(c->path); 1450 packet_put_int(c->host_port); 1451 if (packet_get_protocol_flags() & 1452 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1453 packet_put_cstring(c->remote_name); 1454 packet_send(); 1455 } 1456 xfree(remote_ipaddr); 1457 } 1458 1459 static void 1460 channel_set_reuseaddr(int fd) 1461 { 1462 int on = 1; 1463 1464 /* 1465 * Set socket options. 1466 * Allow local port reuse in TIME_WAIT. 1467 */ 1468 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) 1469 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); 1470 } 1471 1472 /* 1473 * This socket is listening for connections to a forwarded TCP/IP port. 1474 */ 1475 /* ARGSUSED */ 1476 static void 1477 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset) 1478 { 1479 Channel *nc; 1480 struct sockaddr_storage addr; 1481 int newsock, nextstate; 1482 socklen_t addrlen; 1483 const char *rtype; 1484 1485 if (FD_ISSET(c->sock, readset)) { 1486 debug("Connection to port %d forwarding " 1487 "to %.100s port %d requested.", 1488 c->listening_port, c->path, c->host_port); 1489 1490 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1491 nextstate = SSH_CHANNEL_OPENING; 1492 rtype = "forwarded-tcpip"; 1493 } else { 1494 if (c->host_port == 0) { 1495 nextstate = SSH_CHANNEL_DYNAMIC; 1496 rtype = "dynamic-tcpip"; 1497 } else { 1498 nextstate = SSH_CHANNEL_OPENING; 1499 rtype = "direct-tcpip"; 1500 } 1501 } 1502 1503 addrlen = sizeof(addr); 1504 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1505 if (newsock < 0) { 1506 error("accept: %.100s", strerror(errno)); 1507 return; 1508 } 1509 set_nodelay(newsock); 1510 nc = channel_new(rtype, nextstate, newsock, newsock, -1, 1511 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1512 nc->listening_port = c->listening_port; 1513 nc->host_port = c->host_port; 1514 if (c->path != NULL) 1515 nc->path = xstrdup(c->path); 1516 1517 if (nextstate != SSH_CHANNEL_DYNAMIC) 1518 port_open_helper(nc, rtype); 1519 } 1520 } 1521 1522 /* 1523 * This is the authentication agent socket listening for connections from 1524 * clients. 1525 */ 1526 /* ARGSUSED */ 1527 static void 1528 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset) 1529 { 1530 Channel *nc; 1531 int newsock; 1532 struct sockaddr_storage addr; 1533 socklen_t addrlen; 1534 1535 if (FD_ISSET(c->sock, readset)) { 1536 addrlen = sizeof(addr); 1537 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1538 if (newsock < 0) { 1539 error("accept from auth socket: %.100s", strerror(errno)); 1540 return; 1541 } 1542 nc = channel_new("accepted auth socket", 1543 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1544 c->local_window_max, c->local_maxpacket, 1545 0, "accepted auth socket", 1); 1546 if (compat20) { 1547 packet_start(SSH2_MSG_CHANNEL_OPEN); 1548 packet_put_cstring("auth-agent@openssh.com"); 1549 packet_put_int(nc->self); 1550 packet_put_int(c->local_window_max); 1551 packet_put_int(c->local_maxpacket); 1552 } else { 1553 packet_start(SSH_SMSG_AGENT_OPEN); 1554 packet_put_int(nc->self); 1555 } 1556 packet_send(); 1557 } 1558 } 1559 1560 /* ARGSUSED */ 1561 static void 1562 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset) 1563 { 1564 int err = 0, sock; 1565 socklen_t sz = sizeof(err); 1566 1567 if (FD_ISSET(c->sock, writeset)) { 1568 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { 1569 err = errno; 1570 error("getsockopt SO_ERROR failed"); 1571 } 1572 if (err == 0) { 1573 debug("channel %d: connected to %s port %d", 1574 c->self, c->connect_ctx.host, c->connect_ctx.port); 1575 channel_connect_ctx_free(&c->connect_ctx); 1576 c->type = SSH_CHANNEL_OPEN; 1577 if (compat20) { 1578 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1579 packet_put_int(c->remote_id); 1580 packet_put_int(c->self); 1581 packet_put_int(c->local_window); 1582 packet_put_int(c->local_maxpacket); 1583 } else { 1584 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1585 packet_put_int(c->remote_id); 1586 packet_put_int(c->self); 1587 } 1588 } else { 1589 debug("channel %d: connection failed: %s", 1590 c->self, strerror(err)); 1591 /* Try next address, if any */ 1592 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1593 close(c->sock); 1594 c->sock = c->rfd = c->wfd = sock; 1595 channel_max_fd = channel_find_maxfd(); 1596 return; 1597 } 1598 /* Exhausted all addresses */ 1599 error("connect_to %.100s port %d: failed.", 1600 c->connect_ctx.host, c->connect_ctx.port); 1601 channel_connect_ctx_free(&c->connect_ctx); 1602 if (compat20) { 1603 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1604 packet_put_int(c->remote_id); 1605 packet_put_int(SSH2_OPEN_CONNECT_FAILED); 1606 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1607 packet_put_cstring(strerror(err)); 1608 packet_put_cstring(""); 1609 } 1610 } else { 1611 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1612 packet_put_int(c->remote_id); 1613 } 1614 chan_mark_dead(c); 1615 } 1616 packet_send(); 1617 } 1618 } 1619 1620 /* ARGSUSED */ 1621 static int 1622 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset) 1623 { 1624 char buf[CHAN_RBUF]; 1625 int len, force; 1626 1627 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 1628 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) { 1629 len = read(c->rfd, buf, sizeof(buf)); 1630 if (len < 0 && (errno == EINTR || (errno == EAGAIN && !force))) 1631 return 1; 1632 if (len <= 0) { 1633 debug2("channel %d: read<=0 rfd %d len %d", 1634 c->self, c->rfd, len); 1635 if (c->type != SSH_CHANNEL_OPEN) { 1636 debug2("channel %d: not open", c->self); 1637 chan_mark_dead(c); 1638 return -1; 1639 } else if (compat13) { 1640 buffer_clear(&c->output); 1641 c->type = SSH_CHANNEL_INPUT_DRAINING; 1642 debug2("channel %d: input draining.", c->self); 1643 } else { 1644 chan_read_failed(c); 1645 } 1646 return -1; 1647 } 1648 if (c->input_filter != NULL) { 1649 if (c->input_filter(c, buf, len) == -1) { 1650 debug2("channel %d: filter stops", c->self); 1651 chan_read_failed(c); 1652 } 1653 } else if (c->datagram) { 1654 buffer_put_string(&c->input, buf, len); 1655 } else { 1656 buffer_append(&c->input, buf, len); 1657 } 1658 } 1659 return 1; 1660 } 1661 1662 /* ARGSUSED */ 1663 static int 1664 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset) 1665 { 1666 struct termios tio; 1667 u_char *data = NULL, *buf; 1668 u_int dlen, olen = 0; 1669 int len; 1670 1671 /* Send buffered output data to the socket. */ 1672 if (c->wfd != -1 && 1673 FD_ISSET(c->wfd, writeset) && 1674 buffer_len(&c->output) > 0) { 1675 olen = buffer_len(&c->output); 1676 if (c->output_filter != NULL) { 1677 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) { 1678 debug2("channel %d: filter stops", c->self); 1679 if (c->type != SSH_CHANNEL_OPEN) 1680 chan_mark_dead(c); 1681 else 1682 chan_write_failed(c); 1683 return -1; 1684 } 1685 } else if (c->datagram) { 1686 buf = data = buffer_get_string(&c->output, &dlen); 1687 } else { 1688 buf = data = buffer_ptr(&c->output); 1689 dlen = buffer_len(&c->output); 1690 } 1691 1692 if (c->datagram) { 1693 /* ignore truncated writes, datagrams might get lost */ 1694 len = write(c->wfd, buf, dlen); 1695 xfree(data); 1696 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1697 return 1; 1698 if (len <= 0) { 1699 if (c->type != SSH_CHANNEL_OPEN) 1700 chan_mark_dead(c); 1701 else 1702 chan_write_failed(c); 1703 return -1; 1704 } 1705 goto out; 1706 } 1707 1708 len = write(c->wfd, buf, dlen); 1709 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1710 return 1; 1711 if (len <= 0) { 1712 if (c->type != SSH_CHANNEL_OPEN) { 1713 debug2("channel %d: not open", c->self); 1714 chan_mark_dead(c); 1715 return -1; 1716 } else if (compat13) { 1717 buffer_clear(&c->output); 1718 debug2("channel %d: input draining.", c->self); 1719 c->type = SSH_CHANNEL_INPUT_DRAINING; 1720 } else { 1721 chan_write_failed(c); 1722 } 1723 return -1; 1724 } 1725 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') { 1726 if (tcgetattr(c->wfd, &tio) == 0 && 1727 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 1728 /* 1729 * Simulate echo to reduce the impact of 1730 * traffic analysis. We need to match the 1731 * size of a SSH2_MSG_CHANNEL_DATA message 1732 * (4 byte channel id + buf) 1733 */ 1734 packet_send_ignore(4 + len); 1735 packet_send(); 1736 } 1737 } 1738 buffer_consume(&c->output, len); 1739 } 1740 out: 1741 if (compat20 && olen > 0) 1742 c->local_consumed += olen - buffer_len(&c->output); 1743 return 1; 1744 } 1745 1746 static int 1747 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset) 1748 { 1749 char buf[CHAN_RBUF]; 1750 int len; 1751 1752 /** XXX handle drain efd, too */ 1753 if (c->efd != -1) { 1754 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1755 FD_ISSET(c->efd, writeset) && 1756 buffer_len(&c->extended) > 0) { 1757 len = write(c->efd, buffer_ptr(&c->extended), 1758 buffer_len(&c->extended)); 1759 debug2("channel %d: written %d to efd %d", 1760 c->self, len, c->efd); 1761 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1762 return 1; 1763 if (len <= 0) { 1764 debug2("channel %d: closing write-efd %d", 1765 c->self, c->efd); 1766 channel_close_fd(&c->efd); 1767 } else { 1768 buffer_consume(&c->extended, len); 1769 c->local_consumed += len; 1770 } 1771 } else if (c->efd != -1 && 1772 (c->extended_usage == CHAN_EXTENDED_READ || 1773 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1774 FD_ISSET(c->efd, readset)) { 1775 len = read(c->efd, buf, sizeof(buf)); 1776 debug2("channel %d: read %d from efd %d", 1777 c->self, len, c->efd); 1778 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1779 return 1; 1780 if (len <= 0) { 1781 debug2("channel %d: closing read-efd %d", 1782 c->self, c->efd); 1783 channel_close_fd(&c->efd); 1784 } else { 1785 if (c->extended_usage == CHAN_EXTENDED_IGNORE) { 1786 debug3("channel %d: discard efd", 1787 c->self); 1788 } else 1789 buffer_append(&c->extended, buf, len); 1790 } 1791 } 1792 } 1793 return 1; 1794 } 1795 1796 /* ARGSUSED */ 1797 static int 1798 channel_check_window(Channel *c) 1799 { 1800 if (c->type == SSH_CHANNEL_OPEN && 1801 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 1802 ((c->local_window_max - c->local_window > 1803 c->local_maxpacket*3) || 1804 c->local_window < c->local_window_max/2) && 1805 c->local_consumed > 0) { 1806 u_int addition = 0; 1807 /* adjust max window size if we are in a dynamic environment */ 1808 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) { 1809 /* grow the window somewhat aggressively to maintain pressure */ 1810 addition = 1.5*(c->tcpwinsz - c->local_window_max); 1811 c->local_window_max += addition; 1812 } 1813 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 1814 packet_put_int(c->remote_id); 1815 packet_put_int(c->local_consumed + addition); 1816 packet_send(); 1817 debug2("channel %d: window %d sent adjust %d", 1818 c->self, c->local_window, 1819 c->local_consumed); 1820 c->local_window += c->local_consumed + addition; 1821 c->local_consumed = 0; 1822 } 1823 return 1; 1824 } 1825 1826 static void 1827 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset) 1828 { 1829 channel_handle_rfd(c, readset, writeset); 1830 channel_handle_wfd(c, readset, writeset); 1831 if (!compat20) 1832 return; 1833 channel_handle_efd(c, readset, writeset); 1834 channel_check_window(c); 1835 } 1836 1837 static u_int 1838 read_mux(Channel *c, u_int need) 1839 { 1840 char buf[CHAN_RBUF]; 1841 int len; 1842 u_int rlen; 1843 1844 if (buffer_len(&c->input) < need) { 1845 rlen = need - buffer_len(&c->input); 1846 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF)); 1847 if (len <= 0) { 1848 if (errno != EINTR && errno != EAGAIN) { 1849 debug2("channel %d: ctl read<=0 rfd %d len %d", 1850 c->self, c->rfd, len); 1851 chan_read_failed(c); 1852 return 0; 1853 } 1854 } else 1855 buffer_append(&c->input, buf, len); 1856 } 1857 return buffer_len(&c->input); 1858 } 1859 1860 static void 1861 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1862 { 1863 u_int need; 1864 ssize_t len; 1865 1866 if (!compat20) 1867 fatal("%s: entered with !compat20", __func__); 1868 1869 if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) && 1870 (c->istate == CHAN_INPUT_OPEN || 1871 c->istate == CHAN_INPUT_WAIT_DRAIN)) { 1872 /* 1873 * Don't not read past the precise end of packets to 1874 * avoid disrupting fd passing. 1875 */ 1876 if (read_mux(c, 4) < 4) /* read header */ 1877 return; 1878 need = get_u32(buffer_ptr(&c->input)); 1879 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 1880 if (need > CHANNEL_MUX_MAX_PACKET) { 1881 debug2("channel %d: packet too big %u > %u", 1882 c->self, CHANNEL_MUX_MAX_PACKET, need); 1883 chan_rcvd_oclose(c); 1884 return; 1885 } 1886 if (read_mux(c, need + 4) < need + 4) /* read body */ 1887 return; 1888 if (c->mux_rcb(c) != 0) { 1889 debug("channel %d: mux_rcb failed", c->self); 1890 chan_mark_dead(c); 1891 return; 1892 } 1893 } 1894 1895 if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) && 1896 buffer_len(&c->output) > 0) { 1897 len = write(c->wfd, buffer_ptr(&c->output), 1898 buffer_len(&c->output)); 1899 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1900 return; 1901 if (len <= 0) { 1902 chan_mark_dead(c); 1903 return; 1904 } 1905 buffer_consume(&c->output, len); 1906 } 1907 } 1908 1909 static void 1910 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset) 1911 { 1912 Channel *nc; 1913 struct sockaddr_storage addr; 1914 socklen_t addrlen; 1915 int newsock; 1916 uid_t euid; 1917 gid_t egid; 1918 1919 if (!FD_ISSET(c->sock, readset)) 1920 return; 1921 1922 debug("multiplexing control connection"); 1923 1924 /* 1925 * Accept connection on control socket 1926 */ 1927 memset(&addr, 0, sizeof(addr)); 1928 addrlen = sizeof(addr); 1929 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 1930 &addrlen)) == -1) { 1931 error("%s accept: %s", __func__, strerror(errno)); 1932 return; 1933 } 1934 1935 if (getpeereid(newsock, &euid, &egid) < 0) { 1936 error("%s getpeereid failed: %s", __func__, 1937 strerror(errno)); 1938 close(newsock); 1939 return; 1940 } 1941 if ((euid != 0) && (getuid() != euid)) { 1942 error("multiplex uid mismatch: peer euid %u != uid %u", 1943 (u_int)euid, (u_int)getuid()); 1944 close(newsock); 1945 return; 1946 } 1947 nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT, 1948 newsock, newsock, -1, c->local_window_max, 1949 c->local_maxpacket, 0, "mux-control", 1); 1950 nc->mux_rcb = c->mux_rcb; 1951 debug3("%s: new mux channel %d fd %d", __func__, 1952 nc->self, nc->sock); 1953 /* establish state */ 1954 nc->mux_rcb(nc); 1955 /* mux state transitions must not elicit protocol messages */ 1956 nc->flags |= CHAN_LOCAL; 1957 } 1958 1959 /* ARGSUSED */ 1960 static void 1961 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset) 1962 { 1963 int len; 1964 1965 /* Send buffered output data to the socket. */ 1966 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { 1967 len = write(c->sock, buffer_ptr(&c->output), 1968 buffer_len(&c->output)); 1969 if (len <= 0) 1970 buffer_clear(&c->output); 1971 else 1972 buffer_consume(&c->output, len); 1973 } 1974 } 1975 1976 static void 1977 channel_handler_init_20(void) 1978 { 1979 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 1980 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 1981 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 1982 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 1983 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 1984 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 1985 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 1986 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 1987 channel_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 1988 channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 1989 1990 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 1991 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 1992 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 1993 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 1994 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 1995 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 1996 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 1997 channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 1998 channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 1999 } 2000 2001 static void 2002 channel_handler_init_13(void) 2003 { 2004 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; 2005 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; 2006 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2007 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2008 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2009 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; 2010 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; 2011 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2012 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2013 2014 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2015 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2016 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2017 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2018 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; 2019 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2020 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2021 } 2022 2023 static void 2024 channel_handler_init_15(void) 2025 { 2026 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2027 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2028 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2029 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2030 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2031 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2032 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2033 2034 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2035 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2036 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2037 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2038 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2039 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2040 } 2041 2042 static void 2043 channel_handler_init(void) 2044 { 2045 int i; 2046 2047 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { 2048 channel_pre[i] = NULL; 2049 channel_post[i] = NULL; 2050 } 2051 if (compat20) 2052 channel_handler_init_20(); 2053 else if (compat13) 2054 channel_handler_init_13(); 2055 else 2056 channel_handler_init_15(); 2057 } 2058 2059 /* gc dead channels */ 2060 static void 2061 channel_garbage_collect(Channel *c) 2062 { 2063 if (c == NULL) 2064 return; 2065 if (c->detach_user != NULL) { 2066 if (!chan_is_dead(c, c->detach_close)) 2067 return; 2068 debug2("channel %d: gc: notify user", c->self); 2069 c->detach_user(c->self, NULL); 2070 /* if we still have a callback */ 2071 if (c->detach_user != NULL) 2072 return; 2073 debug2("channel %d: gc: user detached", c->self); 2074 } 2075 if (!chan_is_dead(c, 1)) 2076 return; 2077 debug2("channel %d: garbage collecting", c->self); 2078 channel_free(c); 2079 } 2080 2081 static void 2082 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset) 2083 { 2084 static int did_init = 0; 2085 u_int i, oalloc; 2086 Channel *c; 2087 2088 if (!did_init) { 2089 channel_handler_init(); 2090 did_init = 1; 2091 } 2092 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) { 2093 c = channels[i]; 2094 if (c == NULL) 2095 continue; 2096 if (c->delayed) { 2097 if (ftab == channel_pre) 2098 c->delayed = 0; 2099 else 2100 continue; 2101 } 2102 if (ftab[c->type] != NULL) 2103 (*ftab[c->type])(c, readset, writeset); 2104 channel_garbage_collect(c); 2105 } 2106 } 2107 2108 /* 2109 * Allocate/update select bitmasks and add any bits relevant to channels in 2110 * select bitmasks. 2111 */ 2112 void 2113 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, 2114 u_int *nallocp, int rekeying) 2115 { 2116 u_int n, sz, nfdset; 2117 2118 n = MAX(*maxfdp, channel_max_fd); 2119 2120 nfdset = howmany(n+1, NFDBITS); 2121 /* Explicitly test here, because xrealloc isn't always called */ 2122 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask)) 2123 fatal("channel_prepare_select: max_fd (%d) is too large", n); 2124 sz = nfdset * sizeof(fd_mask); 2125 2126 /* perhaps check sz < nalloc/2 and shrink? */ 2127 if (*readsetp == NULL || sz > *nallocp) { 2128 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask)); 2129 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask)); 2130 *nallocp = sz; 2131 } 2132 *maxfdp = n; 2133 memset(*readsetp, 0, sz); 2134 memset(*writesetp, 0, sz); 2135 2136 if (!rekeying) 2137 channel_handler(channel_pre, *readsetp, *writesetp); 2138 } 2139 2140 /* 2141 * After select, perform any appropriate operations for channels which have 2142 * events pending. 2143 */ 2144 void 2145 channel_after_select(fd_set *readset, fd_set *writeset) 2146 { 2147 channel_handler(channel_post, readset, writeset); 2148 } 2149 2150 2151 /* If there is data to send to the connection, enqueue some of it now. */ 2152 int 2153 channel_output_poll(void) 2154 { 2155 Channel *c; 2156 u_int i, len; 2157 int packet_length = 0; 2158 2159 for (i = 0; i < channels_alloc; i++) { 2160 c = channels[i]; 2161 if (c == NULL) 2162 continue; 2163 2164 /* 2165 * We are only interested in channels that can have buffered 2166 * incoming data. 2167 */ 2168 if (compat13) { 2169 if (c->type != SSH_CHANNEL_OPEN && 2170 c->type != SSH_CHANNEL_INPUT_DRAINING) 2171 continue; 2172 } else { 2173 if (c->type != SSH_CHANNEL_OPEN) 2174 continue; 2175 } 2176 if (compat20 && 2177 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2178 /* XXX is this true? */ 2179 debug3("channel %d: will not send data after close", c->self); 2180 continue; 2181 } 2182 2183 /* Get the amount of buffered data for this channel. */ 2184 if ((c->istate == CHAN_INPUT_OPEN || 2185 c->istate == CHAN_INPUT_WAIT_DRAIN) && 2186 (len = buffer_len(&c->input)) > 0) { 2187 if (c->datagram) { 2188 if (len > 0) { 2189 u_char *data; 2190 u_int dlen; 2191 2192 data = buffer_get_string(&c->input, 2193 &dlen); 2194 if (dlen > c->remote_window || 2195 dlen > c->remote_maxpacket) { 2196 debug("channel %d: datagram " 2197 "too big for channel", 2198 c->self); 2199 xfree(data); 2200 continue; 2201 } 2202 packet_start(SSH2_MSG_CHANNEL_DATA); 2203 packet_put_int(c->remote_id); 2204 packet_put_string(data, dlen); 2205 packet_length = packet_send(); 2206 c->remote_window -= dlen + 4; 2207 xfree(data); 2208 } 2209 continue; 2210 } 2211 /* 2212 * Send some data for the other side over the secure 2213 * connection. 2214 */ 2215 if (compat20) { 2216 if (len > c->remote_window) 2217 len = c->remote_window; 2218 if (len > c->remote_maxpacket) 2219 len = c->remote_maxpacket; 2220 } else { 2221 if (packet_is_interactive()) { 2222 if (len > 1024) 2223 len = 512; 2224 } else { 2225 /* Keep the packets at reasonable size. */ 2226 if (len > packet_get_maxsize()/2) 2227 len = packet_get_maxsize()/2; 2228 } 2229 } 2230 if (len > 0) { 2231 packet_start(compat20 ? 2232 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); 2233 packet_put_int(c->remote_id); 2234 packet_put_string(buffer_ptr(&c->input), len); 2235 packet_length = packet_send(); 2236 buffer_consume(&c->input, len); 2237 c->remote_window -= len; 2238 } 2239 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2240 if (compat13) 2241 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); 2242 /* 2243 * input-buffer is empty and read-socket shutdown: 2244 * tell peer, that we will not send more data: send IEOF. 2245 * hack for extended data: delay EOF if EFD still in use. 2246 */ 2247 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2248 debug2("channel %d: ibuf_empty delayed efd %d/(%d)", 2249 c->self, c->efd, buffer_len(&c->extended)); 2250 else 2251 chan_ibuf_empty(c); 2252 } 2253 /* Send extended data, i.e. stderr */ 2254 if (compat20 && 2255 !(c->flags & CHAN_EOF_SENT) && 2256 c->remote_window > 0 && 2257 (len = buffer_len(&c->extended)) > 0 && 2258 c->extended_usage == CHAN_EXTENDED_READ) { 2259 debug2("channel %d: rwin %u elen %u euse %d", 2260 c->self, c->remote_window, buffer_len(&c->extended), 2261 c->extended_usage); 2262 if (len > c->remote_window) 2263 len = c->remote_window; 2264 if (len > c->remote_maxpacket) 2265 len = c->remote_maxpacket; 2266 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); 2267 packet_put_int(c->remote_id); 2268 packet_put_int(SSH2_EXTENDED_DATA_STDERR); 2269 packet_put_string(buffer_ptr(&c->extended), len); 2270 packet_length = packet_send(); 2271 buffer_consume(&c->extended, len); 2272 c->remote_window -= len; 2273 debug2("channel %d: sent ext data %d", c->self, len); 2274 } 2275 } 2276 return (packet_length); 2277 } 2278 2279 2280 /* -- protocol input */ 2281 2282 /* ARGSUSED */ 2283 void 2284 channel_input_data(int type, u_int32_t seq, void *ctxt) 2285 { 2286 int id; 2287 char *data; 2288 u_int data_len, win_len; 2289 Channel *c; 2290 2291 /* Get the channel number and verify it. */ 2292 id = packet_get_int(); 2293 c = channel_lookup(id); 2294 if (c == NULL) 2295 packet_disconnect("Received data for nonexistent channel %d.", id); 2296 2297 /* Ignore any data for non-open channels (might happen on close) */ 2298 if (c->type != SSH_CHANNEL_OPEN && 2299 c->type != SSH_CHANNEL_X11_OPEN) 2300 return; 2301 2302 /* Get the data. */ 2303 data = packet_get_string_ptr(&data_len); 2304 win_len = data_len; 2305 if (c->datagram) 2306 win_len += 4; /* string length header */ 2307 2308 /* 2309 * Ignore data for protocol > 1.3 if output end is no longer open. 2310 * For protocol 2 the sending side is reducing its window as it sends 2311 * data, so we must 'fake' consumption of the data in order to ensure 2312 * that window updates are sent back. Otherwise the connection might 2313 * deadlock. 2314 */ 2315 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { 2316 if (compat20) { 2317 c->local_window -= win_len; 2318 c->local_consumed += win_len; 2319 } 2320 return; 2321 } 2322 2323 if (compat20) { 2324 if (win_len > c->local_maxpacket) { 2325 logit("channel %d: rcvd big packet %d, maxpack %d", 2326 c->self, win_len, c->local_maxpacket); 2327 } 2328 if (win_len > c->local_window) { 2329 logit("channel %d: rcvd too much data %d, win %d", 2330 c->self, win_len, c->local_window); 2331 return; 2332 } 2333 c->local_window -= win_len; 2334 } 2335 if (c->datagram) 2336 buffer_put_string(&c->output, data, data_len); 2337 else 2338 buffer_append(&c->output, data, data_len); 2339 packet_check_eom(); 2340 } 2341 2342 /* ARGSUSED */ 2343 void 2344 channel_input_extended_data(int type, u_int32_t seq, void *ctxt) 2345 { 2346 int id; 2347 char *data; 2348 u_int data_len, tcode; 2349 Channel *c; 2350 2351 /* Get the channel number and verify it. */ 2352 id = packet_get_int(); 2353 c = channel_lookup(id); 2354 2355 if (c == NULL) 2356 packet_disconnect("Received extended_data for bad channel %d.", id); 2357 if (c->type != SSH_CHANNEL_OPEN) { 2358 logit("channel %d: ext data for non open", id); 2359 return; 2360 } 2361 if (c->flags & CHAN_EOF_RCVD) { 2362 if (datafellows & SSH_BUG_EXTEOF) 2363 debug("channel %d: accepting ext data after eof", id); 2364 else 2365 packet_disconnect("Received extended_data after EOF " 2366 "on channel %d.", id); 2367 } 2368 tcode = packet_get_int(); 2369 if (c->efd == -1 || 2370 c->extended_usage != CHAN_EXTENDED_WRITE || 2371 tcode != SSH2_EXTENDED_DATA_STDERR) { 2372 logit("channel %d: bad ext data", c->self); 2373 return; 2374 } 2375 data = packet_get_string(&data_len); 2376 packet_check_eom(); 2377 if (data_len > c->local_window) { 2378 logit("channel %d: rcvd too much extended_data %d, win %d", 2379 c->self, data_len, c->local_window); 2380 xfree(data); 2381 return; 2382 } 2383 debug2("channel %d: rcvd ext data %d", c->self, data_len); 2384 c->local_window -= data_len; 2385 buffer_append(&c->extended, data, data_len); 2386 xfree(data); 2387 } 2388 2389 /* ARGSUSED */ 2390 void 2391 channel_input_ieof(int type, u_int32_t seq, void *ctxt) 2392 { 2393 int id; 2394 Channel *c; 2395 2396 id = packet_get_int(); 2397 packet_check_eom(); 2398 c = channel_lookup(id); 2399 if (c == NULL) 2400 packet_disconnect("Received ieof for nonexistent channel %d.", id); 2401 chan_rcvd_ieof(c); 2402 2403 /* XXX force input close */ 2404 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 2405 debug("channel %d: FORCE input drain", c->self); 2406 c->istate = CHAN_INPUT_WAIT_DRAIN; 2407 if (buffer_len(&c->input) == 0) 2408 chan_ibuf_empty(c); 2409 } 2410 2411 } 2412 2413 /* ARGSUSED */ 2414 void 2415 channel_input_close(int type, u_int32_t seq, void *ctxt) 2416 { 2417 int id; 2418 Channel *c; 2419 2420 id = packet_get_int(); 2421 packet_check_eom(); 2422 c = channel_lookup(id); 2423 if (c == NULL) 2424 packet_disconnect("Received close for nonexistent channel %d.", id); 2425 2426 /* 2427 * Send a confirmation that we have closed the channel and no more 2428 * data is coming for it. 2429 */ 2430 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); 2431 packet_put_int(c->remote_id); 2432 packet_send(); 2433 2434 /* 2435 * If the channel is in closed state, we have sent a close request, 2436 * and the other side will eventually respond with a confirmation. 2437 * Thus, we cannot free the channel here, because then there would be 2438 * no-one to receive the confirmation. The channel gets freed when 2439 * the confirmation arrives. 2440 */ 2441 if (c->type != SSH_CHANNEL_CLOSED) { 2442 /* 2443 * Not a closed channel - mark it as draining, which will 2444 * cause it to be freed later. 2445 */ 2446 buffer_clear(&c->input); 2447 c->type = SSH_CHANNEL_OUTPUT_DRAINING; 2448 } 2449 } 2450 2451 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ 2452 /* ARGSUSED */ 2453 void 2454 channel_input_oclose(int type, u_int32_t seq, void *ctxt) 2455 { 2456 int id = packet_get_int(); 2457 Channel *c = channel_lookup(id); 2458 2459 packet_check_eom(); 2460 if (c == NULL) 2461 packet_disconnect("Received oclose for nonexistent channel %d.", id); 2462 chan_rcvd_oclose(c); 2463 } 2464 2465 /* ARGSUSED */ 2466 void 2467 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) 2468 { 2469 int id = packet_get_int(); 2470 Channel *c = channel_lookup(id); 2471 2472 packet_check_eom(); 2473 if (c == NULL) 2474 packet_disconnect("Received close confirmation for " 2475 "out-of-range channel %d.", id); 2476 if (c->type != SSH_CHANNEL_CLOSED) 2477 packet_disconnect("Received close confirmation for " 2478 "non-closed channel %d (type %d).", id, c->type); 2479 channel_free(c); 2480 } 2481 2482 /* ARGSUSED */ 2483 void 2484 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) 2485 { 2486 int id, remote_id; 2487 Channel *c; 2488 2489 id = packet_get_int(); 2490 c = channel_lookup(id); 2491 2492 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2493 packet_disconnect("Received open confirmation for " 2494 "non-opening channel %d.", id); 2495 remote_id = packet_get_int(); 2496 /* Record the remote channel number and mark that the channel is now open. */ 2497 c->remote_id = remote_id; 2498 c->type = SSH_CHANNEL_OPEN; 2499 2500 if (compat20) { 2501 c->remote_window = packet_get_int(); 2502 c->remote_maxpacket = packet_get_int(); 2503 if (c->open_confirm) { 2504 debug2("callback start"); 2505 c->open_confirm(c->self, 1, c->open_confirm_ctx); 2506 debug2("callback done"); 2507 } 2508 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 2509 c->remote_window, c->remote_maxpacket); 2510 } 2511 packet_check_eom(); 2512 } 2513 2514 static const char * 2515 reason2txt(int reason) 2516 { 2517 switch (reason) { 2518 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 2519 return "administratively prohibited"; 2520 case SSH2_OPEN_CONNECT_FAILED: 2521 return "connect failed"; 2522 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 2523 return "unknown channel type"; 2524 case SSH2_OPEN_RESOURCE_SHORTAGE: 2525 return "resource shortage"; 2526 } 2527 return "unknown reason"; 2528 } 2529 2530 /* ARGSUSED */ 2531 void 2532 channel_input_open_failure(int type, u_int32_t seq, void *ctxt) 2533 { 2534 int id, reason; 2535 char *msg = NULL, *lang = NULL; 2536 Channel *c; 2537 2538 id = packet_get_int(); 2539 c = channel_lookup(id); 2540 2541 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2542 packet_disconnect("Received open failure for " 2543 "non-opening channel %d.", id); 2544 if (compat20) { 2545 reason = packet_get_int(); 2546 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 2547 msg = packet_get_string(NULL); 2548 lang = packet_get_string(NULL); 2549 } 2550 logit("channel %d: open failed: %s%s%s", id, 2551 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 2552 if (msg != NULL) 2553 xfree(msg); 2554 if (lang != NULL) 2555 xfree(lang); 2556 if (c->open_confirm) { 2557 debug2("callback start"); 2558 c->open_confirm(c->self, 0, c->open_confirm_ctx); 2559 debug2("callback done"); 2560 } 2561 } 2562 packet_check_eom(); 2563 /* Schedule the channel for cleanup/deletion. */ 2564 chan_mark_dead(c); 2565 } 2566 2567 /* ARGSUSED */ 2568 void 2569 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) 2570 { 2571 Channel *c; 2572 int id; 2573 u_int adjust; 2574 2575 if (!compat20) 2576 return; 2577 2578 /* Get the channel number and verify it. */ 2579 id = packet_get_int(); 2580 c = channel_lookup(id); 2581 2582 if (c == NULL) { 2583 logit("Received window adjust for non-open channel %d.", id); 2584 return; 2585 } 2586 adjust = packet_get_int(); 2587 packet_check_eom(); 2588 debug2("channel %d: rcvd adjust %u", id, adjust); 2589 c->remote_window += adjust; 2590 } 2591 2592 /* ARGSUSED */ 2593 void 2594 channel_input_port_open(int type, u_int32_t seq, void *ctxt) 2595 { 2596 Channel *c = NULL; 2597 u_short host_port; 2598 char *host, *originator_string; 2599 int remote_id; 2600 2601 remote_id = packet_get_int(); 2602 host = packet_get_string(NULL); 2603 host_port = packet_get_int(); 2604 2605 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 2606 originator_string = packet_get_string(NULL); 2607 } else { 2608 originator_string = xstrdup("unknown (remote did not supply name)"); 2609 } 2610 packet_check_eom(); 2611 c = channel_connect_to(host, host_port, 2612 "connected socket", originator_string); 2613 xfree(originator_string); 2614 xfree(host); 2615 if (c == NULL) { 2616 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 2617 packet_put_int(remote_id); 2618 packet_send(); 2619 } else 2620 c->remote_id = remote_id; 2621 } 2622 2623 /* ARGSUSED */ 2624 void 2625 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt) 2626 { 2627 Channel *c; 2628 struct channel_confirm *cc; 2629 int id; 2630 2631 /* Reset keepalive timeout */ 2632 packet_set_alive_timeouts(0); 2633 2634 id = packet_get_int(); 2635 packet_check_eom(); 2636 2637 debug2("channel_input_status_confirm: type %d id %d", type, id); 2638 2639 if ((c = channel_lookup(id)) == NULL) { 2640 logit("channel_input_status_confirm: %d: unknown", id); 2641 return; 2642 } 2643 ; 2644 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 2645 return; 2646 cc->cb(type, c, cc->ctx); 2647 TAILQ_REMOVE(&c->status_confirms, cc, entry); 2648 bzero(cc, sizeof(*cc)); 2649 xfree(cc); 2650 } 2651 2652 /* -- tcp forwarding */ 2653 2654 void 2655 channel_set_af(int af) 2656 { 2657 IPv4or6 = af; 2658 } 2659 2660 2661 void 2662 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size) 2663 { 2664 hpn_disabled = external_hpn_disabled; 2665 hpn_buffer_size = external_hpn_buffer_size; 2666 debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size); 2667 } 2668 2669 static int 2670 channel_setup_fwd_listener(int type, const char *listen_addr, 2671 u_short listen_port, int *allocated_listen_port, 2672 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2673 { 2674 Channel *c; 2675 int sock, r, success = 0, wildcard = 0, is_client; 2676 struct addrinfo hints, *ai, *aitop; 2677 const char *host, *addr; 2678 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 2679 in_port_t *lport_p; 2680 2681 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 2682 listen_addr : host_to_connect; 2683 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 2684 2685 if (host == NULL) { 2686 error("No forward host name."); 2687 return 0; 2688 } 2689 if (strlen(host) >= NI_MAXHOST) { 2690 error("Forward host name too long."); 2691 return 0; 2692 } 2693 2694 /* 2695 * Determine whether or not a port forward listens to loopback, 2696 * specified address or wildcard. On the client, a specified bind 2697 * address will always override gateway_ports. On the server, a 2698 * gateway_ports of 1 (``yes'') will override the client's 2699 * specification and force a wildcard bind, whereas a value of 2 2700 * (``clientspecified'') will bind to whatever address the client 2701 * asked for. 2702 * 2703 * Special-case listen_addrs are: 2704 * 2705 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 2706 * "" (empty string), "*" -> wildcard v4/v6 2707 * "localhost" -> loopback v4/v6 2708 */ 2709 addr = NULL; 2710 if (listen_addr == NULL) { 2711 /* No address specified: default to gateway_ports setting */ 2712 if (gateway_ports) 2713 wildcard = 1; 2714 } else if (gateway_ports || is_client) { 2715 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 2716 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 2717 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 2718 (!is_client && gateway_ports == 1)) 2719 wildcard = 1; 2720 else if (strcmp(listen_addr, "localhost") != 0) 2721 addr = listen_addr; 2722 } 2723 2724 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s", 2725 type, wildcard, (addr == NULL) ? "NULL" : addr); 2726 2727 /* 2728 * getaddrinfo returns a loopback address if the hostname is 2729 * set to NULL and hints.ai_flags is not AI_PASSIVE 2730 */ 2731 memset(&hints, 0, sizeof(hints)); 2732 hints.ai_family = IPv4or6; 2733 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 2734 hints.ai_socktype = SOCK_STREAM; 2735 snprintf(strport, sizeof strport, "%d", listen_port); 2736 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 2737 if (addr == NULL) { 2738 /* This really shouldn't happen */ 2739 packet_disconnect("getaddrinfo: fatal error: %s", 2740 ssh_gai_strerror(r)); 2741 } else { 2742 error("channel_setup_fwd_listener: " 2743 "getaddrinfo(%.64s): %s", addr, 2744 ssh_gai_strerror(r)); 2745 } 2746 return 0; 2747 } 2748 if (allocated_listen_port != NULL) 2749 *allocated_listen_port = 0; 2750 for (ai = aitop; ai; ai = ai->ai_next) { 2751 switch (ai->ai_family) { 2752 case AF_INET: 2753 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 2754 sin_port; 2755 break; 2756 case AF_INET6: 2757 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 2758 sin6_port; 2759 break; 2760 default: 2761 continue; 2762 } 2763 /* 2764 * If allocating a port for -R forwards, then use the 2765 * same port for all address families. 2766 */ 2767 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 && 2768 allocated_listen_port != NULL && *allocated_listen_port > 0) 2769 *lport_p = htons(*allocated_listen_port); 2770 2771 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 2772 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 2773 error("channel_setup_fwd_listener: getnameinfo failed"); 2774 continue; 2775 } 2776 /* Create a port to listen for the host. */ 2777 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 2778 if (sock < 0) { 2779 /* this is no error since kernel may not support ipv6 */ 2780 verbose("socket: %.100s", strerror(errno)); 2781 continue; 2782 } 2783 2784 channel_set_reuseaddr(sock); 2785 2786 debug("Local forwarding listening on %s port %s.", 2787 ntop, strport); 2788 2789 /* Bind the socket to the address. */ 2790 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 2791 /* address can be in use ipv6 address is already bound */ 2792 verbose("bind: %.100s", strerror(errno)); 2793 close(sock); 2794 continue; 2795 } 2796 /* Start listening for connections on the socket. */ 2797 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 2798 error("listen: %.100s", strerror(errno)); 2799 close(sock); 2800 continue; 2801 } 2802 2803 /* 2804 * listen_port == 0 requests a dynamically allocated port - 2805 * record what we got. 2806 */ 2807 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 && 2808 allocated_listen_port != NULL && 2809 *allocated_listen_port == 0) { 2810 *allocated_listen_port = get_sock_port(sock, 1); 2811 debug("Allocated listen port %d", 2812 *allocated_listen_port); 2813 } 2814 2815 /* Allocate a channel number for the socket. */ 2816 /* explicitly test for hpn disabled option. if true use smaller window size */ 2817 if (hpn_disabled) 2818 c = channel_new("port listener", type, sock, sock, -1, 2819 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 2820 0, "port listener", 1); 2821 else 2822 c = channel_new("port listener", type, sock, sock, -1, 2823 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 2824 0, "port listener", 1); 2825 c->path = xstrdup(host); 2826 c->host_port = port_to_connect; 2827 c->listening_port = listen_port; 2828 success = 1; 2829 } 2830 if (success == 0) 2831 error("channel_setup_fwd_listener: cannot listen to port: %d", 2832 listen_port); 2833 freeaddrinfo(aitop); 2834 return success; 2835 } 2836 2837 int 2838 channel_cancel_rport_listener(const char *host, u_short port) 2839 { 2840 u_int i; 2841 int found = 0; 2842 2843 for (i = 0; i < channels_alloc; i++) { 2844 Channel *c = channels[i]; 2845 2846 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER && 2847 strcmp(c->path, host) == 0 && c->listening_port == port) { 2848 debug2("%s: close channel %d", __func__, i); 2849 channel_free(c); 2850 found = 1; 2851 } 2852 } 2853 2854 return (found); 2855 } 2856 2857 /* protocol local port fwd, used by ssh (and sshd in v1) */ 2858 int 2859 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port, 2860 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2861 { 2862 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, 2863 listen_host, listen_port, NULL, host_to_connect, port_to_connect, 2864 gateway_ports); 2865 } 2866 2867 /* protocol v2 remote port fwd, used by sshd */ 2868 int 2869 channel_setup_remote_fwd_listener(const char *listen_address, 2870 u_short listen_port, int *allocated_listen_port, int gateway_ports) 2871 { 2872 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, 2873 listen_address, listen_port, allocated_listen_port, 2874 NULL, 0, gateway_ports); 2875 } 2876 2877 /* 2878 * Initiate forwarding of connections to port "port" on remote host through 2879 * the secure channel to host:port from local side. 2880 */ 2881 2882 int 2883 channel_request_remote_forwarding(const char *listen_host, u_short listen_port, 2884 const char *host_to_connect, u_short port_to_connect) 2885 { 2886 int type, success = 0; 2887 2888 /* Send the forward request to the remote side. */ 2889 if (compat20) { 2890 const char *address_to_bind; 2891 if (listen_host == NULL) { 2892 if (datafellows & SSH_BUG_RFWD_ADDR) 2893 address_to_bind = "127.0.0.1"; 2894 else 2895 address_to_bind = "localhost"; 2896 } else if (*listen_host == '\0' || 2897 strcmp(listen_host, "*") == 0) { 2898 if (datafellows & SSH_BUG_RFWD_ADDR) 2899 address_to_bind = "0.0.0.0"; 2900 else 2901 address_to_bind = ""; 2902 } else 2903 address_to_bind = listen_host; 2904 2905 packet_start(SSH2_MSG_GLOBAL_REQUEST); 2906 packet_put_cstring("tcpip-forward"); 2907 packet_put_char(1); /* boolean: want reply */ 2908 packet_put_cstring(address_to_bind); 2909 packet_put_int(listen_port); 2910 packet_send(); 2911 packet_write_wait(); 2912 /* Assume that server accepts the request */ 2913 success = 1; 2914 } else { 2915 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); 2916 packet_put_int(listen_port); 2917 packet_put_cstring(host_to_connect); 2918 packet_put_int(port_to_connect); 2919 packet_send(); 2920 packet_write_wait(); 2921 2922 /* Wait for response from the remote side. */ 2923 type = packet_read(); 2924 switch (type) { 2925 case SSH_SMSG_SUCCESS: 2926 success = 1; 2927 break; 2928 case SSH_SMSG_FAILURE: 2929 break; 2930 default: 2931 /* Unknown packet */ 2932 packet_disconnect("Protocol error for port forward request:" 2933 "received packet type %d.", type); 2934 } 2935 } 2936 if (success) { 2937 /* Record that connection to this host/port is permitted. */ 2938 permitted_opens = xrealloc(permitted_opens, 2939 num_permitted_opens + 1, sizeof(*permitted_opens)); 2940 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); 2941 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; 2942 permitted_opens[num_permitted_opens].listen_port = listen_port; 2943 num_permitted_opens++; 2944 } 2945 return (success ? 0 : -1); 2946 } 2947 2948 /* 2949 * Request cancellation of remote forwarding of connection host:port from 2950 * local side. 2951 */ 2952 void 2953 channel_request_rforward_cancel(const char *host, u_short port) 2954 { 2955 int i; 2956 2957 if (!compat20) 2958 return; 2959 2960 for (i = 0; i < num_permitted_opens; i++) { 2961 if (permitted_opens[i].host_to_connect != NULL && 2962 permitted_opens[i].listen_port == port) 2963 break; 2964 } 2965 if (i >= num_permitted_opens) { 2966 debug("%s: requested forward not found", __func__); 2967 return; 2968 } 2969 packet_start(SSH2_MSG_GLOBAL_REQUEST); 2970 packet_put_cstring("cancel-tcpip-forward"); 2971 packet_put_char(0); 2972 packet_put_cstring(host == NULL ? "" : host); 2973 packet_put_int(port); 2974 packet_send(); 2975 2976 permitted_opens[i].listen_port = 0; 2977 permitted_opens[i].port_to_connect = 0; 2978 xfree(permitted_opens[i].host_to_connect); 2979 permitted_opens[i].host_to_connect = NULL; 2980 } 2981 2982 /* 2983 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates 2984 * listening for the port, and sends back a success reply (or disconnect 2985 * message if there was an error). 2986 */ 2987 int 2988 channel_input_port_forward_request(int is_root, int gateway_ports) 2989 { 2990 u_short port, host_port; 2991 int success = 0; 2992 char *hostname; 2993 2994 /* Get arguments from the packet. */ 2995 port = packet_get_int(); 2996 hostname = packet_get_string(NULL); 2997 host_port = packet_get_int(); 2998 2999 /* 3000 * Check that an unprivileged user is not trying to forward a 3001 * privileged port. 3002 */ 3003 if (port < IPPORT_RESERVED && !is_root) 3004 packet_disconnect( 3005 "Requested forwarding of port %d but user is not root.", 3006 port); 3007 if (host_port == 0) 3008 packet_disconnect("Dynamic forwarding denied."); 3009 3010 /* Initiate forwarding */ 3011 success = channel_setup_local_fwd_listener(NULL, port, hostname, 3012 host_port, gateway_ports); 3013 3014 /* Free the argument string. */ 3015 xfree(hostname); 3016 3017 return (success ? 0 : -1); 3018 } 3019 3020 /* 3021 * Permits opening to any host/port if permitted_opens[] is empty. This is 3022 * usually called by the server, because the user could connect to any port 3023 * anyway, and the server has no way to know but to trust the client anyway. 3024 */ 3025 void 3026 channel_permit_all_opens(void) 3027 { 3028 if (num_permitted_opens == 0) 3029 all_opens_permitted = 1; 3030 } 3031 3032 void 3033 channel_add_permitted_opens(char *host, int port) 3034 { 3035 debug("allow port forwarding to host %s port %d", host, port); 3036 3037 permitted_opens = xrealloc(permitted_opens, 3038 num_permitted_opens + 1, sizeof(*permitted_opens)); 3039 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); 3040 permitted_opens[num_permitted_opens].port_to_connect = port; 3041 num_permitted_opens++; 3042 3043 all_opens_permitted = 0; 3044 } 3045 3046 int 3047 channel_add_adm_permitted_opens(char *host, int port) 3048 { 3049 debug("config allows port forwarding to host %s port %d", host, port); 3050 3051 permitted_adm_opens = xrealloc(permitted_adm_opens, 3052 num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens)); 3053 permitted_adm_opens[num_adm_permitted_opens].host_to_connect 3054 = xstrdup(host); 3055 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port; 3056 return ++num_adm_permitted_opens; 3057 } 3058 3059 void 3060 channel_clear_permitted_opens(void) 3061 { 3062 int i; 3063 3064 for (i = 0; i < num_permitted_opens; i++) 3065 if (permitted_opens[i].host_to_connect != NULL) 3066 xfree(permitted_opens[i].host_to_connect); 3067 if (num_permitted_opens > 0) { 3068 xfree(permitted_opens); 3069 permitted_opens = NULL; 3070 } 3071 num_permitted_opens = 0; 3072 } 3073 3074 void 3075 channel_clear_adm_permitted_opens(void) 3076 { 3077 int i; 3078 3079 for (i = 0; i < num_adm_permitted_opens; i++) 3080 if (permitted_adm_opens[i].host_to_connect != NULL) 3081 xfree(permitted_adm_opens[i].host_to_connect); 3082 if (num_adm_permitted_opens > 0) { 3083 xfree(permitted_adm_opens); 3084 permitted_adm_opens = NULL; 3085 } 3086 num_adm_permitted_opens = 0; 3087 } 3088 3089 void 3090 channel_print_adm_permitted_opens(void) 3091 { 3092 int i; 3093 3094 printf("permitopen"); 3095 if (num_adm_permitted_opens == 0) { 3096 printf(" any\n"); 3097 return; 3098 } 3099 for (i = 0; i < num_adm_permitted_opens; i++) 3100 if (permitted_adm_opens[i].host_to_connect != NULL) 3101 printf(" %s:%d", permitted_adm_opens[i].host_to_connect, 3102 permitted_adm_opens[i].port_to_connect); 3103 printf("\n"); 3104 } 3105 3106 /* Try to start non-blocking connect to next host in cctx list */ 3107 static int 3108 connect_next(struct channel_connect *cctx) 3109 { 3110 int sock, saved_errno; 3111 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3112 3113 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 3114 if (cctx->ai->ai_family != AF_INET && 3115 cctx->ai->ai_family != AF_INET6) 3116 continue; 3117 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 3118 ntop, sizeof(ntop), strport, sizeof(strport), 3119 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3120 error("connect_next: getnameinfo failed"); 3121 continue; 3122 } 3123 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 3124 cctx->ai->ai_protocol)) == -1) { 3125 if (cctx->ai->ai_next == NULL) 3126 error("socket: %.100s", strerror(errno)); 3127 else 3128 verbose("socket: %.100s", strerror(errno)); 3129 continue; 3130 } 3131 if (set_nonblock(sock) == -1) 3132 fatal("%s: set_nonblock(%d)", __func__, sock); 3133 if (connect(sock, cctx->ai->ai_addr, 3134 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 3135 debug("connect_next: host %.100s ([%.100s]:%s): " 3136 "%.100s", cctx->host, ntop, strport, 3137 strerror(errno)); 3138 saved_errno = errno; 3139 close(sock); 3140 errno = saved_errno; 3141 continue; /* fail -- try next */ 3142 } 3143 debug("connect_next: host %.100s ([%.100s]:%s) " 3144 "in progress, fd=%d", cctx->host, ntop, strport, sock); 3145 cctx->ai = cctx->ai->ai_next; 3146 set_nodelay(sock); 3147 return sock; 3148 } 3149 return -1; 3150 } 3151 3152 static void 3153 channel_connect_ctx_free(struct channel_connect *cctx) 3154 { 3155 xfree(cctx->host); 3156 if (cctx->aitop) 3157 freeaddrinfo(cctx->aitop); 3158 bzero(cctx, sizeof(*cctx)); 3159 cctx->host = NULL; 3160 cctx->ai = cctx->aitop = NULL; 3161 } 3162 3163 /* Return CONNECTING channel to remote host, port */ 3164 static Channel * 3165 connect_to(const char *host, u_short port, const char *ctype, const char *rname) 3166 { 3167 struct addrinfo hints; 3168 int gaierr; 3169 int sock = -1; 3170 char strport[NI_MAXSERV]; 3171 struct channel_connect cctx; 3172 Channel *c; 3173 3174 memset(&cctx, 0, sizeof(cctx)); 3175 memset(&hints, 0, sizeof(hints)); 3176 hints.ai_family = IPv4or6; 3177 hints.ai_socktype = SOCK_STREAM; 3178 snprintf(strport, sizeof strport, "%d", port); 3179 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) { 3180 error("connect_to %.100s: unknown host (%s)", host, 3181 ssh_gai_strerror(gaierr)); 3182 return NULL; 3183 } 3184 3185 cctx.host = xstrdup(host); 3186 cctx.port = port; 3187 cctx.ai = cctx.aitop; 3188 3189 if ((sock = connect_next(&cctx)) == -1) { 3190 error("connect to %.100s port %d failed: %s", 3191 host, port, strerror(errno)); 3192 channel_connect_ctx_free(&cctx); 3193 return NULL; 3194 } 3195 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 3196 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 3197 c->connect_ctx = cctx; 3198 return c; 3199 } 3200 3201 Channel * 3202 channel_connect_by_listen_address(u_short listen_port, const char *ctype, 3203 const char *rname) 3204 { 3205 int i; 3206 3207 for (i = 0; i < num_permitted_opens; i++) { 3208 if (permitted_opens[i].host_to_connect != NULL && 3209 permitted_opens[i].listen_port == listen_port) { 3210 return connect_to( 3211 permitted_opens[i].host_to_connect, 3212 permitted_opens[i].port_to_connect, ctype, rname); 3213 } 3214 } 3215 error("WARNING: Server requests forwarding for unknown listen_port %d", 3216 listen_port); 3217 return NULL; 3218 } 3219 3220 /* Check if connecting to that port is permitted and connect. */ 3221 Channel * 3222 channel_connect_to(const char *host, u_short port, const char *ctype, 3223 const char *rname) 3224 { 3225 int i, permit, permit_adm = 1; 3226 3227 permit = all_opens_permitted; 3228 if (!permit) { 3229 for (i = 0; i < num_permitted_opens; i++) 3230 if (permitted_opens[i].host_to_connect != NULL && 3231 permitted_opens[i].port_to_connect == port && 3232 strcmp(permitted_opens[i].host_to_connect, host) == 0) 3233 permit = 1; 3234 } 3235 3236 if (num_adm_permitted_opens > 0) { 3237 permit_adm = 0; 3238 for (i = 0; i < num_adm_permitted_opens; i++) 3239 if (permitted_adm_opens[i].host_to_connect != NULL && 3240 permitted_adm_opens[i].port_to_connect == port && 3241 strcmp(permitted_adm_opens[i].host_to_connect, host) 3242 == 0) 3243 permit_adm = 1; 3244 } 3245 3246 if (!permit || !permit_adm) { 3247 logit("Received request to connect to host %.100s port %d, " 3248 "but the request was denied.", host, port); 3249 return NULL; 3250 } 3251 return connect_to(host, port, ctype, rname); 3252 } 3253 3254 void 3255 channel_send_window_changes(void) 3256 { 3257 u_int i; 3258 struct winsize ws; 3259 3260 for (i = 0; i < channels_alloc; i++) { 3261 if (channels[i] == NULL || !channels[i]->client_tty || 3262 channels[i]->type != SSH_CHANNEL_OPEN) 3263 continue; 3264 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) 3265 continue; 3266 channel_request_start(i, "window-change", 0); 3267 packet_put_int((u_int)ws.ws_col); 3268 packet_put_int((u_int)ws.ws_row); 3269 packet_put_int((u_int)ws.ws_xpixel); 3270 packet_put_int((u_int)ws.ws_ypixel); 3271 packet_send(); 3272 } 3273 } 3274 3275 /* -- X11 forwarding */ 3276 3277 /* 3278 * Creates an internet domain socket for listening for X11 connections. 3279 * Returns 0 and a suitable display number for the DISPLAY variable 3280 * stored in display_numberp , or -1 if an error occurs. 3281 */ 3282 int 3283 x11_create_display_inet(int x11_display_offset, int x11_use_localhost, 3284 int single_connection, u_int *display_numberp, int **chanids) 3285 { 3286 Channel *nc = NULL; 3287 int display_number, sock; 3288 u_short port; 3289 struct addrinfo hints, *ai, *aitop; 3290 char strport[NI_MAXSERV]; 3291 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 3292 3293 if (chanids == NULL) 3294 return -1; 3295 3296 for (display_number = x11_display_offset; 3297 display_number < MAX_DISPLAYS; 3298 display_number++) { 3299 port = 6000 + display_number; 3300 memset(&hints, 0, sizeof(hints)); 3301 hints.ai_family = IPv4or6; 3302 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 3303 hints.ai_socktype = SOCK_STREAM; 3304 snprintf(strport, sizeof strport, "%d", port); 3305 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { 3306 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 3307 return -1; 3308 } 3309 for (ai = aitop; ai; ai = ai->ai_next) { 3310 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 3311 continue; 3312 sock = socket(ai->ai_family, ai->ai_socktype, 3313 ai->ai_protocol); 3314 if (sock < 0) { 3315 error("socket: %.100s", strerror(errno)); 3316 freeaddrinfo(aitop); 3317 return -1; 3318 } 3319 channel_set_reuseaddr(sock); 3320 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3321 debug2("bind port %d: %.100s", port, strerror(errno)); 3322 close(sock); 3323 3324 for (n = 0; n < num_socks; n++) { 3325 close(socks[n]); 3326 } 3327 num_socks = 0; 3328 break; 3329 } 3330 socks[num_socks++] = sock; 3331 if (num_socks == NUM_SOCKS) 3332 break; 3333 } 3334 freeaddrinfo(aitop); 3335 if (num_socks > 0) 3336 break; 3337 } 3338 if (display_number >= MAX_DISPLAYS) { 3339 error("Failed to allocate internet-domain X11 display socket."); 3340 return -1; 3341 } 3342 /* Start listening for connections on the socket. */ 3343 for (n = 0; n < num_socks; n++) { 3344 sock = socks[n]; 3345 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 3346 error("listen: %.100s", strerror(errno)); 3347 close(sock); 3348 return -1; 3349 } 3350 } 3351 3352 /* Allocate a channel for each socket. */ 3353 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 3354 for (n = 0; n < num_socks; n++) { 3355 sock = socks[n]; 3356 /* Is this really necassary? */ 3357 if (hpn_disabled) 3358 nc = channel_new("x11 listener", 3359 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 3360 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 3361 0, "X11 inet listener", 1); 3362 else 3363 nc = channel_new("x11 listener", 3364 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 3365 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 3366 0, "X11 inet listener", 1); 3367 nc->single_connection = single_connection; 3368 (*chanids)[n] = nc->self; 3369 } 3370 (*chanids)[n] = -1; 3371 3372 /* Return the display number for the DISPLAY environment variable. */ 3373 *display_numberp = display_number; 3374 return (0); 3375 } 3376 3377 static int 3378 connect_local_xsocket(u_int dnr) 3379 { 3380 int sock; 3381 struct sockaddr_un addr; 3382 3383 sock = socket(AF_UNIX, SOCK_STREAM, 0); 3384 if (sock < 0) 3385 error("socket: %.100s", strerror(errno)); 3386 memset(&addr, 0, sizeof(addr)); 3387 addr.sun_family = AF_UNIX; 3388 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 3389 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 3390 return sock; 3391 close(sock); 3392 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 3393 return -1; 3394 } 3395 3396 int 3397 x11_connect_display(void) 3398 { 3399 u_int display_number; 3400 const char *display; 3401 char buf[1024], *cp; 3402 struct addrinfo hints, *ai, *aitop; 3403 char strport[NI_MAXSERV]; 3404 int gaierr, sock = 0; 3405 3406 /* Try to open a socket for the local X server. */ 3407 display = getenv("DISPLAY"); 3408 if (!display) { 3409 error("DISPLAY not set."); 3410 return -1; 3411 } 3412 /* 3413 * Now we decode the value of the DISPLAY variable and make a 3414 * connection to the real X server. 3415 */ 3416 3417 /* 3418 * Check if it is a unix domain socket. Unix domain displays are in 3419 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 3420 */ 3421 if (strncmp(display, "unix:", 5) == 0 || 3422 display[0] == ':') { 3423 /* Connect to the unix domain socket. */ 3424 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) { 3425 error("Could not parse display number from DISPLAY: %.100s", 3426 display); 3427 return -1; 3428 } 3429 /* Create a socket. */ 3430 sock = connect_local_xsocket(display_number); 3431 if (sock < 0) 3432 return -1; 3433 3434 /* OK, we now have a connection to the display. */ 3435 return sock; 3436 } 3437 /* 3438 * Connect to an inet socket. The DISPLAY value is supposedly 3439 * hostname:d[.s], where hostname may also be numeric IP address. 3440 */ 3441 strlcpy(buf, display, sizeof(buf)); 3442 cp = strchr(buf, ':'); 3443 if (!cp) { 3444 error("Could not find ':' in DISPLAY: %.100s", display); 3445 return -1; 3446 } 3447 *cp = 0; 3448 /* buf now contains the host name. But first we parse the display number. */ 3449 if (sscanf(cp + 1, "%u", &display_number) != 1) { 3450 error("Could not parse display number from DISPLAY: %.100s", 3451 display); 3452 return -1; 3453 } 3454 3455 /* Look up the host address */ 3456 memset(&hints, 0, sizeof(hints)); 3457 hints.ai_family = IPv4or6; 3458 hints.ai_socktype = SOCK_STREAM; 3459 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 3460 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 3461 error("%.100s: unknown host. (%s)", buf, 3462 ssh_gai_strerror(gaierr)); 3463 return -1; 3464 } 3465 for (ai = aitop; ai; ai = ai->ai_next) { 3466 /* Create a socket. */ 3467 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3468 if (sock < 0) { 3469 debug2("socket: %.100s", strerror(errno)); 3470 continue; 3471 } 3472 /* Connect it to the display. */ 3473 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3474 debug2("connect %.100s port %u: %.100s", buf, 3475 6000 + display_number, strerror(errno)); 3476 close(sock); 3477 continue; 3478 } 3479 /* Success */ 3480 break; 3481 } 3482 freeaddrinfo(aitop); 3483 if (!ai) { 3484 error("connect %.100s port %u: %.100s", buf, 6000 + display_number, 3485 strerror(errno)); 3486 return -1; 3487 } 3488 set_nodelay(sock); 3489 return sock; 3490 } 3491 3492 /* 3493 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains 3494 * the remote channel number. We should do whatever we want, and respond 3495 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. 3496 */ 3497 3498 /* ARGSUSED */ 3499 void 3500 x11_input_open(int type, u_int32_t seq, void *ctxt) 3501 { 3502 Channel *c = NULL; 3503 int remote_id, sock = 0; 3504 char *remote_host; 3505 3506 debug("Received X11 open request."); 3507 3508 remote_id = packet_get_int(); 3509 3510 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 3511 remote_host = packet_get_string(NULL); 3512 } else { 3513 remote_host = xstrdup("unknown (remote did not supply name)"); 3514 } 3515 packet_check_eom(); 3516 3517 /* Obtain a connection to the real X display. */ 3518 sock = x11_connect_display(); 3519 if (sock != -1) { 3520 /* Allocate a channel for this connection. */ 3521 c = channel_new("connected x11 socket", 3522 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, 3523 remote_host, 1); 3524 c->remote_id = remote_id; 3525 c->force_drain = 1; 3526 } 3527 xfree(remote_host); 3528 if (c == NULL) { 3529 /* Send refusal to the remote host. */ 3530 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3531 packet_put_int(remote_id); 3532 } else { 3533 /* Send a confirmation to the remote host. */ 3534 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 3535 packet_put_int(remote_id); 3536 packet_put_int(c->self); 3537 } 3538 packet_send(); 3539 } 3540 3541 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ 3542 /* ARGSUSED */ 3543 void 3544 deny_input_open(int type, u_int32_t seq, void *ctxt) 3545 { 3546 int rchan = packet_get_int(); 3547 3548 switch (type) { 3549 case SSH_SMSG_AGENT_OPEN: 3550 error("Warning: ssh server tried agent forwarding."); 3551 break; 3552 case SSH_SMSG_X11_OPEN: 3553 error("Warning: ssh server tried X11 forwarding."); 3554 break; 3555 default: 3556 error("deny_input_open: type %d", type); 3557 break; 3558 } 3559 error("Warning: this is probably a break-in attempt by a malicious server."); 3560 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3561 packet_put_int(rchan); 3562 packet_send(); 3563 } 3564 3565 /* 3566 * Requests forwarding of X11 connections, generates fake authentication 3567 * data, and enables authentication spoofing. 3568 * This should be called in the client only. 3569 */ 3570 void 3571 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp, 3572 const char *proto, const char *data, int want_reply) 3573 { 3574 u_int data_len = (u_int) strlen(data) / 2; 3575 u_int i, value; 3576 char *new_data; 3577 int screen_number; 3578 const char *cp; 3579 u_int32_t rnd = 0; 3580 3581 if (x11_saved_display == NULL) 3582 x11_saved_display = xstrdup(disp); 3583 else if (strcmp(disp, x11_saved_display) != 0) { 3584 error("x11_request_forwarding_with_spoofing: different " 3585 "$DISPLAY already forwarded"); 3586 return; 3587 } 3588 3589 cp = strchr(disp, ':'); 3590 if (cp) 3591 cp = strchr(cp, '.'); 3592 if (cp) 3593 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 3594 else 3595 screen_number = 0; 3596 3597 if (x11_saved_proto == NULL) { 3598 /* Save protocol name. */ 3599 x11_saved_proto = xstrdup(proto); 3600 /* 3601 * Extract real authentication data and generate fake data 3602 * of the same length. 3603 */ 3604 x11_saved_data = xmalloc(data_len); 3605 x11_fake_data = xmalloc(data_len); 3606 for (i = 0; i < data_len; i++) { 3607 if (sscanf(data + 2 * i, "%2x", &value) != 1) 3608 fatal("x11_request_forwarding: bad " 3609 "authentication data: %.100s", data); 3610 if (i % 4 == 0) 3611 rnd = arc4random(); 3612 x11_saved_data[i] = value; 3613 x11_fake_data[i] = rnd & 0xff; 3614 rnd >>= 8; 3615 } 3616 x11_saved_data_len = data_len; 3617 x11_fake_data_len = data_len; 3618 } 3619 3620 /* Convert the fake data into hex. */ 3621 new_data = tohex(x11_fake_data, data_len); 3622 3623 /* Send the request packet. */ 3624 if (compat20) { 3625 channel_request_start(client_session_id, "x11-req", want_reply); 3626 packet_put_char(0); /* XXX bool single connection */ 3627 } else { 3628 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); 3629 } 3630 packet_put_cstring(proto); 3631 packet_put_cstring(new_data); 3632 packet_put_int(screen_number); 3633 packet_send(); 3634 packet_write_wait(); 3635 xfree(new_data); 3636 } 3637 3638 3639 /* -- agent forwarding */ 3640 3641 /* Sends a message to the server to request authentication fd forwarding. */ 3642 3643 void 3644 auth_request_forwarding(void) 3645 { 3646 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); 3647 packet_send(); 3648 packet_write_wait(); 3649 } 3650