1/* $OpenBSD: channels.c,v 1.319 2012/12/02 20:46:11 djm Exp $ */ 2/* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42#include "includes.h" 43 44#include <sys/types.h> 45#include <sys/ioctl.h> 46#include <sys/un.h> 47#include <sys/socket.h> 48#ifdef HAVE_SYS_TIME_H 49# include <sys/time.h> 50#endif 51 52#include <netinet/in.h> 53#include <arpa/inet.h> 54 55#include <errno.h> 56#include <fcntl.h> 57#include <netdb.h> 58#include <stdio.h> 59#include <stdlib.h> 60#include <string.h> 61#include <termios.h> 62#include <unistd.h> 63#include <stdarg.h> 64 65#include "openbsd-compat/sys-queue.h" 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/* -- channel core */ 82 83/* 84 * Pointer to an array containing all allocated channels. The array is 85 * dynamically extended as needed. 86 */ 87static Channel **channels = NULL; 88 89/* 90 * Size of the channel array. All slots of the array must always be 91 * initialized (at least the type field); unused slots set to NULL 92 */ 93static u_int channels_alloc = 0; 94 95/* 96 * Maximum file descriptor value used in any of the channels. This is 97 * updated in channel_new. 98 */ 99static int channel_max_fd = 0; 100 101 102/* -- tcp forwarding */ 103 104/* 105 * Data structure for storing which hosts are permitted for forward requests. 106 * The local sides of any remote forwards are stored in this array to prevent 107 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 108 * network (which might be behind a firewall). 109 */ 110typedef struct { 111 char *host_to_connect; /* Connect to 'host'. */ 112 u_short port_to_connect; /* Connect to 'port'. */ 113 u_short listen_port; /* Remote side should listen port number. */ 114} ForwardPermission; 115 116/* List of all permitted host/port pairs to connect by the user. */ 117static ForwardPermission *permitted_opens = NULL; 118 119/* List of all permitted host/port pairs to connect by the admin. */ 120static ForwardPermission *permitted_adm_opens = NULL; 121 122/* Number of permitted host/port pairs in the array permitted by the user. */ 123static int num_permitted_opens = 0; 124 125/* Number of permitted host/port pair in the array permitted by the admin. */ 126static int num_adm_permitted_opens = 0; 127 128/* special-case port number meaning allow any port */ 129#define FWD_PERMIT_ANY_PORT 0 130 131/* 132 * If this is true, all opens are permitted. This is the case on the server 133 * on which we have to trust the client anyway, and the user could do 134 * anything after logging in anyway. 135 */ 136static int all_opens_permitted = 0; 137 138 139/* -- X11 forwarding */ 140 141/* Maximum number of fake X11 displays to try. */ 142#define MAX_DISPLAYS 1000 143 144/* Saved X11 local (client) display. */ 145static char *x11_saved_display = NULL; 146 147/* Saved X11 authentication protocol name. */ 148static char *x11_saved_proto = NULL; 149 150/* Saved X11 authentication data. This is the real data. */ 151static char *x11_saved_data = NULL; 152static u_int x11_saved_data_len = 0; 153 154/* 155 * Fake X11 authentication data. This is what the server will be sending us; 156 * we should replace any occurrences of this by the real data. 157 */ 158static u_char *x11_fake_data = NULL; 159static u_int x11_fake_data_len; 160 161 162/* -- agent forwarding */ 163 164#define NUM_SOCKS 10 165 166/* AF_UNSPEC or AF_INET or AF_INET6 */ 167static int IPv4or6 = AF_UNSPEC; 168 169/* helper */ 170static void port_open_helper(Channel *c, char *rtype); 171 172/* non-blocking connect helpers */ 173static int connect_next(struct channel_connect *); 174static void channel_connect_ctx_free(struct channel_connect *); 175 176/* -- channel core */ 177 178Channel * 179channel_by_id(int id) 180{ 181 Channel *c; 182 183 if (id < 0 || (u_int)id >= channels_alloc) { 184 logit("channel_by_id: %d: bad id", id); 185 return NULL; 186 } 187 c = channels[id]; 188 if (c == NULL) { 189 logit("channel_by_id: %d: bad id: channel free", id); 190 return NULL; 191 } 192 return c; 193} 194 195/* 196 * Returns the channel if it is allowed to receive protocol messages. 197 * Private channels, like listening sockets, may not receive messages. 198 */ 199Channel * 200channel_lookup(int id) 201{ 202 Channel *c; 203 204 if ((c = channel_by_id(id)) == NULL) 205 return (NULL); 206 207 switch (c->type) { 208 case SSH_CHANNEL_X11_OPEN: 209 case SSH_CHANNEL_LARVAL: 210 case SSH_CHANNEL_CONNECTING: 211 case SSH_CHANNEL_DYNAMIC: 212 case SSH_CHANNEL_OPENING: 213 case SSH_CHANNEL_OPEN: 214 case SSH_CHANNEL_INPUT_DRAINING: 215 case SSH_CHANNEL_OUTPUT_DRAINING: 216 return (c); 217 } 218 logit("Non-public channel %d, type %d.", id, c->type); 219 return (NULL); 220} 221 222/* 223 * Register filedescriptors for a channel, used when allocating a channel or 224 * when the channel consumer/producer is ready, e.g. shell exec'd 225 */ 226static void 227channel_register_fds(Channel *c, int rfd, int wfd, int efd, 228 int extusage, int nonblock, int is_tty) 229{ 230 /* Update the maximum file descriptor value. */ 231 channel_max_fd = MAX(channel_max_fd, rfd); 232 channel_max_fd = MAX(channel_max_fd, wfd); 233 channel_max_fd = MAX(channel_max_fd, efd); 234 235 if (rfd != -1) 236 fcntl(rfd, F_SETFD, FD_CLOEXEC); 237 if (wfd != -1 && wfd != rfd) 238 fcntl(wfd, F_SETFD, FD_CLOEXEC); 239 if (efd != -1 && efd != rfd && efd != wfd) 240 fcntl(efd, F_SETFD, FD_CLOEXEC); 241 242 c->rfd = rfd; 243 c->wfd = wfd; 244 c->sock = (rfd == wfd) ? rfd : -1; 245 c->efd = efd; 246 c->extended_usage = extusage; 247 248 if ((c->isatty = is_tty) != 0) 249 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 250 c->wfd_isatty = is_tty || isatty(c->wfd); 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 */ 267Channel * 268channel_new(char *ctype, int type, int rfd, int wfd, int efd, 269 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) 270{ 271 int found; 272 u_int i; 273 Channel *c; 274 275 /* Do initial allocation if this is the first call. */ 276 if (channels_alloc == 0) { 277 channels_alloc = 10; 278 channels = xcalloc(channels_alloc, sizeof(Channel *)); 279 for (i = 0; i < channels_alloc; i++) 280 channels[i] = NULL; 281 } 282 /* Try to find a free slot where to put the new channel. */ 283 for (found = -1, i = 0; i < channels_alloc; i++) 284 if (channels[i] == NULL) { 285 /* Found a free slot. */ 286 found = (int)i; 287 break; 288 } 289 if (found < 0) { 290 /* There are no free slots. Take last+1 slot and expand the array. */ 291 found = channels_alloc; 292 if (channels_alloc > 10000) 293 fatal("channel_new: internal error: channels_alloc %d " 294 "too big.", channels_alloc); 295 channels = xrealloc(channels, channels_alloc + 10, 296 sizeof(Channel *)); 297 channels_alloc += 10; 298 debug2("channel: expanding %d", channels_alloc); 299 for (i = found; i < channels_alloc; i++) 300 channels[i] = NULL; 301 } 302 /* Initialize and return new channel. */ 303 c = channels[found] = xcalloc(1, sizeof(Channel)); 304 buffer_init(&c->input); 305 buffer_init(&c->output); 306 buffer_init(&c->extended); 307 c->path = NULL; 308 c->listening_addr = NULL; 309 c->listening_port = 0; 310 c->ostate = CHAN_OUTPUT_OPEN; 311 c->istate = CHAN_INPUT_OPEN; 312 c->flags = 0; 313 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0); 314 c->notbefore = 0; 315 c->self = found; 316 c->type = type; 317 c->ctype = ctype; 318 c->local_window = window; 319 c->local_window_max = window; 320 c->local_consumed = 0; 321 c->local_maxpacket = maxpack; 322 c->remote_id = -1; 323 c->remote_name = xstrdup(remote_name); 324 c->remote_window = 0; 325 c->remote_maxpacket = 0; 326 c->force_drain = 0; 327 c->single_connection = 0; 328 c->detach_user = NULL; 329 c->detach_close = 0; 330 c->open_confirm = NULL; 331 c->open_confirm_ctx = NULL; 332 c->input_filter = NULL; 333 c->output_filter = NULL; 334 c->filter_ctx = NULL; 335 c->filter_cleanup = NULL; 336 c->ctl_chan = -1; 337 c->mux_rcb = NULL; 338 c->mux_ctx = NULL; 339 c->mux_pause = 0; 340 c->delayed = 1; /* prevent call to channel_post handler */ 341 TAILQ_INIT(&c->status_confirms); 342 debug("channel %d: new [%s]", found, remote_name); 343 return c; 344} 345 346static int 347channel_find_maxfd(void) 348{ 349 u_int i; 350 int max = 0; 351 Channel *c; 352 353 for (i = 0; i < channels_alloc; i++) { 354 c = channels[i]; 355 if (c != NULL) { 356 max = MAX(max, c->rfd); 357 max = MAX(max, c->wfd); 358 max = MAX(max, c->efd); 359 } 360 } 361 return max; 362} 363 364int 365channel_close_fd(int *fdp) 366{ 367 int ret = 0, fd = *fdp; 368 369 if (fd != -1) { 370 ret = close(fd); 371 *fdp = -1; 372 if (fd == channel_max_fd) 373 channel_max_fd = channel_find_maxfd(); 374 } 375 return ret; 376} 377 378/* Close all channel fd/socket. */ 379static void 380channel_close_fds(Channel *c) 381{ 382 channel_close_fd(&c->sock); 383 channel_close_fd(&c->rfd); 384 channel_close_fd(&c->wfd); 385 channel_close_fd(&c->efd); 386} 387 388/* Free the channel and close its fd/socket. */ 389void 390channel_free(Channel *c) 391{ 392 char *s; 393 u_int i, n; 394 struct channel_confirm *cc; 395 396 for (n = 0, i = 0; i < channels_alloc; i++) 397 if (channels[i]) 398 n++; 399 debug("channel %d: free: %s, nchannels %u", c->self, 400 c->remote_name ? c->remote_name : "???", n); 401 402 s = channel_open_message(); 403 debug3("channel %d: status: %s", c->self, s); 404 xfree(s); 405 406 if (c->sock != -1) 407 shutdown(c->sock, SHUT_RDWR); 408 channel_close_fds(c); 409 buffer_free(&c->input); 410 buffer_free(&c->output); 411 buffer_free(&c->extended); 412 if (c->remote_name) { 413 xfree(c->remote_name); 414 c->remote_name = NULL; 415 } 416 if (c->path) { 417 xfree(c->path); 418 c->path = NULL; 419 } 420 if (c->listening_addr) { 421 xfree(c->listening_addr); 422 c->listening_addr = NULL; 423 } 424 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 425 if (cc->abandon_cb != NULL) 426 cc->abandon_cb(c, cc->ctx); 427 TAILQ_REMOVE(&c->status_confirms, cc, entry); 428 bzero(cc, sizeof(*cc)); 429 xfree(cc); 430 } 431 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 432 c->filter_cleanup(c->self, c->filter_ctx); 433 channels[c->self] = NULL; 434 xfree(c); 435} 436 437void 438channel_free_all(void) 439{ 440 u_int i; 441 442 for (i = 0; i < channels_alloc; i++) 443 if (channels[i] != NULL) 444 channel_free(channels[i]); 445} 446 447/* 448 * Closes the sockets/fds of all channels. This is used to close extra file 449 * descriptors after a fork. 450 */ 451void 452channel_close_all(void) 453{ 454 u_int i; 455 456 for (i = 0; i < channels_alloc; i++) 457 if (channels[i] != NULL) 458 channel_close_fds(channels[i]); 459} 460 461/* 462 * Stop listening to channels. 463 */ 464void 465channel_stop_listening(void) 466{ 467 u_int i; 468 Channel *c; 469 470 for (i = 0; i < channels_alloc; i++) { 471 c = channels[i]; 472 if (c != NULL) { 473 switch (c->type) { 474 case SSH_CHANNEL_AUTH_SOCKET: 475 case SSH_CHANNEL_PORT_LISTENER: 476 case SSH_CHANNEL_RPORT_LISTENER: 477 case SSH_CHANNEL_X11_LISTENER: 478 channel_close_fd(&c->sock); 479 channel_free(c); 480 break; 481 } 482 } 483 } 484} 485 486/* 487 * Returns true if no channel has too much buffered data, and false if one or 488 * more channel is overfull. 489 */ 490int 491channel_not_very_much_buffered_data(void) 492{ 493 u_int i; 494 Channel *c; 495 496 for (i = 0; i < channels_alloc; i++) { 497 c = channels[i]; 498 if (c != NULL && c->type == SSH_CHANNEL_OPEN) { 499#if 0 500 if (!compat20 && 501 buffer_len(&c->input) > packet_get_maxsize()) { 502 debug2("channel %d: big input buffer %d", 503 c->self, buffer_len(&c->input)); 504 return 0; 505 } 506#endif 507 if (buffer_len(&c->output) > packet_get_maxsize()) { 508 debug2("channel %d: big output buffer %u > %u", 509 c->self, buffer_len(&c->output), 510 packet_get_maxsize()); 511 return 0; 512 } 513 } 514 } 515 return 1; 516} 517 518/* Returns true if any channel is still open. */ 519int 520channel_still_open(void) 521{ 522 u_int i; 523 Channel *c; 524 525 for (i = 0; i < channels_alloc; i++) { 526 c = channels[i]; 527 if (c == NULL) 528 continue; 529 switch (c->type) { 530 case SSH_CHANNEL_X11_LISTENER: 531 case SSH_CHANNEL_PORT_LISTENER: 532 case SSH_CHANNEL_RPORT_LISTENER: 533 case SSH_CHANNEL_MUX_LISTENER: 534 case SSH_CHANNEL_CLOSED: 535 case SSH_CHANNEL_AUTH_SOCKET: 536 case SSH_CHANNEL_DYNAMIC: 537 case SSH_CHANNEL_CONNECTING: 538 case SSH_CHANNEL_ZOMBIE: 539 continue; 540 case SSH_CHANNEL_LARVAL: 541 if (!compat20) 542 fatal("cannot happen: SSH_CHANNEL_LARVAL"); 543 continue; 544 case SSH_CHANNEL_OPENING: 545 case SSH_CHANNEL_OPEN: 546 case SSH_CHANNEL_X11_OPEN: 547 case SSH_CHANNEL_MUX_CLIENT: 548 return 1; 549 case SSH_CHANNEL_INPUT_DRAINING: 550 case SSH_CHANNEL_OUTPUT_DRAINING: 551 if (!compat13) 552 fatal("cannot happen: OUT_DRAIN"); 553 return 1; 554 default: 555 fatal("channel_still_open: bad channel type %d", c->type); 556 /* NOTREACHED */ 557 } 558 } 559 return 0; 560} 561 562/* Returns the id of an open channel suitable for keepaliving */ 563int 564channel_find_open(void) 565{ 566 u_int i; 567 Channel *c; 568 569 for (i = 0; i < channels_alloc; i++) { 570 c = channels[i]; 571 if (c == NULL || c->remote_id < 0) 572 continue; 573 switch (c->type) { 574 case SSH_CHANNEL_CLOSED: 575 case SSH_CHANNEL_DYNAMIC: 576 case SSH_CHANNEL_X11_LISTENER: 577 case SSH_CHANNEL_PORT_LISTENER: 578 case SSH_CHANNEL_RPORT_LISTENER: 579 case SSH_CHANNEL_MUX_LISTENER: 580 case SSH_CHANNEL_MUX_CLIENT: 581 case SSH_CHANNEL_OPENING: 582 case SSH_CHANNEL_CONNECTING: 583 case SSH_CHANNEL_ZOMBIE: 584 continue; 585 case SSH_CHANNEL_LARVAL: 586 case SSH_CHANNEL_AUTH_SOCKET: 587 case SSH_CHANNEL_OPEN: 588 case SSH_CHANNEL_X11_OPEN: 589 return i; 590 case SSH_CHANNEL_INPUT_DRAINING: 591 case SSH_CHANNEL_OUTPUT_DRAINING: 592 if (!compat13) 593 fatal("cannot happen: OUT_DRAIN"); 594 return i; 595 default: 596 fatal("channel_find_open: bad channel type %d", c->type); 597 /* NOTREACHED */ 598 } 599 } 600 return -1; 601} 602 603 604/* 605 * Returns a message describing the currently open forwarded connections, 606 * suitable for sending to the client. The message contains crlf pairs for 607 * newlines. 608 */ 609char * 610channel_open_message(void) 611{ 612 Buffer buffer; 613 Channel *c; 614 char buf[1024], *cp; 615 u_int i; 616 617 buffer_init(&buffer); 618 snprintf(buf, sizeof buf, "The following connections are open:\r\n"); 619 buffer_append(&buffer, buf, strlen(buf)); 620 for (i = 0; i < channels_alloc; i++) { 621 c = channels[i]; 622 if (c == NULL) 623 continue; 624 switch (c->type) { 625 case SSH_CHANNEL_X11_LISTENER: 626 case SSH_CHANNEL_PORT_LISTENER: 627 case SSH_CHANNEL_RPORT_LISTENER: 628 case SSH_CHANNEL_CLOSED: 629 case SSH_CHANNEL_AUTH_SOCKET: 630 case SSH_CHANNEL_ZOMBIE: 631 case SSH_CHANNEL_MUX_CLIENT: 632 case SSH_CHANNEL_MUX_LISTENER: 633 continue; 634 case SSH_CHANNEL_LARVAL: 635 case SSH_CHANNEL_OPENING: 636 case SSH_CHANNEL_CONNECTING: 637 case SSH_CHANNEL_DYNAMIC: 638 case SSH_CHANNEL_OPEN: 639 case SSH_CHANNEL_X11_OPEN: 640 case SSH_CHANNEL_INPUT_DRAINING: 641 case SSH_CHANNEL_OUTPUT_DRAINING: 642 snprintf(buf, sizeof buf, 643 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n", 644 c->self, c->remote_name, 645 c->type, c->remote_id, 646 c->istate, buffer_len(&c->input), 647 c->ostate, buffer_len(&c->output), 648 c->rfd, c->wfd, c->ctl_chan); 649 buffer_append(&buffer, buf, strlen(buf)); 650 continue; 651 default: 652 fatal("channel_open_message: bad channel type %d", c->type); 653 /* NOTREACHED */ 654 } 655 } 656 buffer_append(&buffer, "\0", 1); 657 cp = xstrdup(buffer_ptr(&buffer)); 658 buffer_free(&buffer); 659 return cp; 660} 661 662void 663channel_send_open(int id) 664{ 665 Channel *c = channel_lookup(id); 666 667 if (c == NULL) { 668 logit("channel_send_open: %d: bad id", id); 669 return; 670 } 671 debug2("channel %d: send open", id); 672 packet_start(SSH2_MSG_CHANNEL_OPEN); 673 packet_put_cstring(c->ctype); 674 packet_put_int(c->self); 675 packet_put_int(c->local_window); 676 packet_put_int(c->local_maxpacket); 677 packet_send(); 678} 679 680void 681channel_request_start(int id, char *service, int wantconfirm) 682{ 683 Channel *c = channel_lookup(id); 684 685 if (c == NULL) { 686 logit("channel_request_start: %d: unknown channel id", id); 687 return; 688 } 689 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 690 packet_start(SSH2_MSG_CHANNEL_REQUEST); 691 packet_put_int(c->remote_id); 692 packet_put_cstring(service); 693 packet_put_char(wantconfirm); 694} 695 696void 697channel_register_status_confirm(int id, channel_confirm_cb *cb, 698 channel_confirm_abandon_cb *abandon_cb, void *ctx) 699{ 700 struct channel_confirm *cc; 701 Channel *c; 702 703 if ((c = channel_lookup(id)) == NULL) 704 fatal("channel_register_expect: %d: bad id", id); 705 706 cc = xmalloc(sizeof(*cc)); 707 cc->cb = cb; 708 cc->abandon_cb = abandon_cb; 709 cc->ctx = ctx; 710 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 711} 712 713void 714channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx) 715{ 716 Channel *c = channel_lookup(id); 717 718 if (c == NULL) { 719 logit("channel_register_open_confirm: %d: bad id", id); 720 return; 721 } 722 c->open_confirm = fn; 723 c->open_confirm_ctx = ctx; 724} 725 726void 727channel_register_cleanup(int id, channel_callback_fn *fn, int do_close) 728{ 729 Channel *c = channel_by_id(id); 730 731 if (c == NULL) { 732 logit("channel_register_cleanup: %d: bad id", id); 733 return; 734 } 735 c->detach_user = fn; 736 c->detach_close = do_close; 737} 738 739void 740channel_cancel_cleanup(int id) 741{ 742 Channel *c = channel_by_id(id); 743 744 if (c == NULL) { 745 logit("channel_cancel_cleanup: %d: bad id", id); 746 return; 747 } 748 c->detach_user = NULL; 749 c->detach_close = 0; 750} 751 752void 753channel_register_filter(int id, channel_infilter_fn *ifn, 754 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 755{ 756 Channel *c = channel_lookup(id); 757 758 if (c == NULL) { 759 logit("channel_register_filter: %d: bad id", id); 760 return; 761 } 762 c->input_filter = ifn; 763 c->output_filter = ofn; 764 c->filter_ctx = ctx; 765 c->filter_cleanup = cfn; 766} 767 768void 769channel_set_fds(int id, int rfd, int wfd, int efd, 770 int extusage, int nonblock, int is_tty, u_int window_max) 771{ 772 Channel *c = channel_lookup(id); 773 774 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 775 fatal("channel_activate for non-larval channel %d.", id); 776 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty); 777 c->type = SSH_CHANNEL_OPEN; 778 c->local_window = c->local_window_max = window_max; 779 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 780 packet_put_int(c->remote_id); 781 packet_put_int(c->local_window); 782 packet_send(); 783} 784 785/* 786 * 'channel_pre*' are called just before select() to add any bits relevant to 787 * channels in the select bitmasks. 788 */ 789/* 790 * 'channel_post*': perform any appropriate operations for channels which 791 * have events pending. 792 */ 793typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset); 794chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; 795chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; 796 797/* ARGSUSED */ 798static void 799channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset) 800{ 801 FD_SET(c->sock, readset); 802} 803 804/* ARGSUSED */ 805static void 806channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset) 807{ 808 debug3("channel %d: waiting for connection", c->self); 809 FD_SET(c->sock, writeset); 810} 811 812static void 813channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset) 814{ 815 if (buffer_len(&c->input) < packet_get_maxsize()) 816 FD_SET(c->sock, readset); 817 if (buffer_len(&c->output) > 0) 818 FD_SET(c->sock, writeset); 819} 820 821static void 822channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset) 823{ 824 u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); 825 826 if (c->istate == CHAN_INPUT_OPEN && 827 limit > 0 && 828 buffer_len(&c->input) < limit && 829 buffer_check_alloc(&c->input, CHAN_RBUF)) 830 FD_SET(c->rfd, readset); 831 if (c->ostate == CHAN_OUTPUT_OPEN || 832 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 833 if (buffer_len(&c->output) > 0) { 834 FD_SET(c->wfd, writeset); 835 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 836 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 837 debug2("channel %d: obuf_empty delayed efd %d/(%d)", 838 c->self, c->efd, buffer_len(&c->extended)); 839 else 840 chan_obuf_empty(c); 841 } 842 } 843 /** XXX check close conditions, too */ 844 if (compat20 && c->efd != -1 && 845 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) { 846 if (c->extended_usage == CHAN_EXTENDED_WRITE && 847 buffer_len(&c->extended) > 0) 848 FD_SET(c->efd, writeset); 849 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 850 (c->extended_usage == CHAN_EXTENDED_READ || 851 c->extended_usage == CHAN_EXTENDED_IGNORE) && 852 buffer_len(&c->extended) < c->remote_window) 853 FD_SET(c->efd, readset); 854 } 855 /* XXX: What about efd? races? */ 856} 857 858/* ARGSUSED */ 859static void 860channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset) 861{ 862 if (buffer_len(&c->input) == 0) { 863 packet_start(SSH_MSG_CHANNEL_CLOSE); 864 packet_put_int(c->remote_id); 865 packet_send(); 866 c->type = SSH_CHANNEL_CLOSED; 867 debug2("channel %d: closing after input drain.", c->self); 868 } 869} 870 871/* ARGSUSED */ 872static void 873channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset) 874{ 875 if (buffer_len(&c->output) == 0) 876 chan_mark_dead(c); 877 else 878 FD_SET(c->sock, writeset); 879} 880 881/* 882 * This is a special state for X11 authentication spoofing. An opened X11 883 * connection (when authentication spoofing is being done) remains in this 884 * state until the first packet has been completely read. The authentication 885 * data in that packet is then substituted by the real data if it matches the 886 * fake data, and the channel is put into normal mode. 887 * XXX All this happens at the client side. 888 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 889 */ 890static int 891x11_open_helper(Buffer *b) 892{ 893 u_char *ucp; 894 u_int proto_len, data_len; 895 896 /* Check if the fixed size part of the packet is in buffer. */ 897 if (buffer_len(b) < 12) 898 return 0; 899 900 /* Parse the lengths of variable-length fields. */ 901 ucp = buffer_ptr(b); 902 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 903 proto_len = 256 * ucp[6] + ucp[7]; 904 data_len = 256 * ucp[8] + ucp[9]; 905 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 906 proto_len = ucp[6] + 256 * ucp[7]; 907 data_len = ucp[8] + 256 * ucp[9]; 908 } else { 909 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 910 ucp[0]); 911 return -1; 912 } 913 914 /* Check if the whole packet is in buffer. */ 915 if (buffer_len(b) < 916 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 917 return 0; 918 919 /* Check if authentication protocol matches. */ 920 if (proto_len != strlen(x11_saved_proto) || 921 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { 922 debug2("X11 connection uses different authentication protocol."); 923 return -1; 924 } 925 /* Check if authentication data matches our fake data. */ 926 if (data_len != x11_fake_data_len || 927 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 928 x11_fake_data, x11_fake_data_len) != 0) { 929 debug2("X11 auth data does not match fake data."); 930 return -1; 931 } 932 /* Check fake data length */ 933 if (x11_fake_data_len != x11_saved_data_len) { 934 error("X11 fake_data_len %d != saved_data_len %d", 935 x11_fake_data_len, x11_saved_data_len); 936 return -1; 937 } 938 /* 939 * Received authentication protocol and data match 940 * our fake data. Substitute the fake data with real 941 * data. 942 */ 943 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 944 x11_saved_data, x11_saved_data_len); 945 return 1; 946} 947 948static void 949channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset) 950{ 951 int ret = x11_open_helper(&c->output); 952 953 if (ret == 1) { 954 /* Start normal processing for the channel. */ 955 c->type = SSH_CHANNEL_OPEN; 956 channel_pre_open_13(c, readset, writeset); 957 } else if (ret == -1) { 958 /* 959 * We have received an X11 connection that has bad 960 * authentication information. 961 */ 962 logit("X11 connection rejected because of wrong authentication."); 963 buffer_clear(&c->input); 964 buffer_clear(&c->output); 965 channel_close_fd(&c->sock); 966 c->sock = -1; 967 c->type = SSH_CHANNEL_CLOSED; 968 packet_start(SSH_MSG_CHANNEL_CLOSE); 969 packet_put_int(c->remote_id); 970 packet_send(); 971 } 972} 973 974static void 975channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset) 976{ 977 int ret = x11_open_helper(&c->output); 978 979 /* c->force_drain = 1; */ 980 981 if (ret == 1) { 982 c->type = SSH_CHANNEL_OPEN; 983 channel_pre_open(c, readset, writeset); 984 } else if (ret == -1) { 985 logit("X11 connection rejected because of wrong authentication."); 986 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); 987 chan_read_failed(c); 988 buffer_clear(&c->input); 989 chan_ibuf_empty(c); 990 buffer_clear(&c->output); 991 /* for proto v1, the peer will send an IEOF */ 992 if (compat20) 993 chan_write_failed(c); 994 else 995 c->type = SSH_CHANNEL_OPEN; 996 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 997 } 998} 999 1000static void 1001channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1002{ 1003 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1004 buffer_check_alloc(&c->input, CHAN_RBUF)) 1005 FD_SET(c->rfd, readset); 1006 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1007 /* clear buffer immediately (discard any partial packet) */ 1008 buffer_clear(&c->input); 1009 chan_ibuf_empty(c); 1010 /* Start output drain. XXX just kill chan? */ 1011 chan_rcvd_oclose(c); 1012 } 1013 if (c->ostate == CHAN_OUTPUT_OPEN || 1014 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1015 if (buffer_len(&c->output) > 0) 1016 FD_SET(c->wfd, writeset); 1017 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1018 chan_obuf_empty(c); 1019 } 1020} 1021 1022/* try to decode a socks4 header */ 1023/* ARGSUSED */ 1024static int 1025channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset) 1026{ 1027 char *p, *host; 1028 u_int len, have, i, found, need; 1029 char username[256]; 1030 struct { 1031 u_int8_t version; 1032 u_int8_t command; 1033 u_int16_t dest_port; 1034 struct in_addr dest_addr; 1035 } s4_req, s4_rsp; 1036 1037 debug2("channel %d: decode socks4", c->self); 1038 1039 have = buffer_len(&c->input); 1040 len = sizeof(s4_req); 1041 if (have < len) 1042 return 0; 1043 p = buffer_ptr(&c->input); 1044 1045 need = 1; 1046 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1047 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1048 debug2("channel %d: socks4a request", c->self); 1049 /* ... and needs an extra string (the hostname) */ 1050 need = 2; 1051 } 1052 /* Check for terminating NUL on the string(s) */ 1053 for (found = 0, i = len; i < have; i++) { 1054 if (p[i] == '\0') { 1055 found++; 1056 if (found == need) 1057 break; 1058 } 1059 if (i > 1024) { 1060 /* the peer is probably sending garbage */ 1061 debug("channel %d: decode socks4: too long", 1062 c->self); 1063 return -1; 1064 } 1065 } 1066 if (found < need) 1067 return 0; 1068 buffer_get(&c->input, (char *)&s4_req.version, 1); 1069 buffer_get(&c->input, (char *)&s4_req.command, 1); 1070 buffer_get(&c->input, (char *)&s4_req.dest_port, 2); 1071 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); 1072 have = buffer_len(&c->input); 1073 p = buffer_ptr(&c->input); 1074 len = strlen(p); 1075 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1076 len++; /* trailing '\0' */ 1077 if (len > have) 1078 fatal("channel %d: decode socks4: len %d > have %d", 1079 c->self, len, have); 1080 strlcpy(username, p, sizeof(username)); 1081 buffer_consume(&c->input, len); 1082 1083 if (c->path != NULL) { 1084 xfree(c->path); 1085 c->path = NULL; 1086 } 1087 if (need == 1) { /* SOCKS4: one string */ 1088 host = inet_ntoa(s4_req.dest_addr); 1089 c->path = xstrdup(host); 1090 } else { /* SOCKS4A: two strings */ 1091 have = buffer_len(&c->input); 1092 p = buffer_ptr(&c->input); 1093 len = strlen(p); 1094 debug2("channel %d: decode socks4a: host %s/%d", 1095 c->self, p, len); 1096 len++; /* trailing '\0' */ 1097 if (len > have) 1098 fatal("channel %d: decode socks4a: len %d > have %d", 1099 c->self, len, have); 1100 if (len > NI_MAXHOST) { 1101 error("channel %d: hostname \"%.100s\" too long", 1102 c->self, p); 1103 return -1; 1104 } 1105 c->path = xstrdup(p); 1106 buffer_consume(&c->input, len); 1107 } 1108 c->host_port = ntohs(s4_req.dest_port); 1109 1110 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1111 c->self, c->path, c->host_port, s4_req.command); 1112 1113 if (s4_req.command != 1) { 1114 debug("channel %d: cannot handle: %s cn %d", 1115 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1116 return -1; 1117 } 1118 s4_rsp.version = 0; /* vn: 0 for reply */ 1119 s4_rsp.command = 90; /* cd: req granted */ 1120 s4_rsp.dest_port = 0; /* ignored */ 1121 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1122 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp)); 1123 return 1; 1124} 1125 1126/* try to decode a socks5 header */ 1127#define SSH_SOCKS5_AUTHDONE 0x1000 1128#define SSH_SOCKS5_NOAUTH 0x00 1129#define SSH_SOCKS5_IPV4 0x01 1130#define SSH_SOCKS5_DOMAIN 0x03 1131#define SSH_SOCKS5_IPV6 0x04 1132#define SSH_SOCKS5_CONNECT 0x01 1133#define SSH_SOCKS5_SUCCESS 0x00 1134 1135/* ARGSUSED */ 1136static int 1137channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset) 1138{ 1139 struct { 1140 u_int8_t version; 1141 u_int8_t command; 1142 u_int8_t reserved; 1143 u_int8_t atyp; 1144 } s5_req, s5_rsp; 1145 u_int16_t dest_port; 1146 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1147 u_int have, need, i, found, nmethods, addrlen, af; 1148 1149 debug2("channel %d: decode socks5", c->self); 1150 p = buffer_ptr(&c->input); 1151 if (p[0] != 0x05) 1152 return -1; 1153 have = buffer_len(&c->input); 1154 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1155 /* format: ver | nmethods | methods */ 1156 if (have < 2) 1157 return 0; 1158 nmethods = p[1]; 1159 if (have < nmethods + 2) 1160 return 0; 1161 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1162 for (found = 0, i = 2; i < nmethods + 2; i++) { 1163 if (p[i] == SSH_SOCKS5_NOAUTH) { 1164 found = 1; 1165 break; 1166 } 1167 } 1168 if (!found) { 1169 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1170 c->self); 1171 return -1; 1172 } 1173 buffer_consume(&c->input, nmethods + 2); 1174 buffer_put_char(&c->output, 0x05); /* version */ 1175 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ 1176 FD_SET(c->sock, writeset); 1177 c->flags |= SSH_SOCKS5_AUTHDONE; 1178 debug2("channel %d: socks5 auth done", c->self); 1179 return 0; /* need more */ 1180 } 1181 debug2("channel %d: socks5 post auth", c->self); 1182 if (have < sizeof(s5_req)+1) 1183 return 0; /* need more */ 1184 memcpy(&s5_req, p, sizeof(s5_req)); 1185 if (s5_req.version != 0x05 || 1186 s5_req.command != SSH_SOCKS5_CONNECT || 1187 s5_req.reserved != 0x00) { 1188 debug2("channel %d: only socks5 connect supported", c->self); 1189 return -1; 1190 } 1191 switch (s5_req.atyp){ 1192 case SSH_SOCKS5_IPV4: 1193 addrlen = 4; 1194 af = AF_INET; 1195 break; 1196 case SSH_SOCKS5_DOMAIN: 1197 addrlen = p[sizeof(s5_req)]; 1198 af = -1; 1199 break; 1200 case SSH_SOCKS5_IPV6: 1201 addrlen = 16; 1202 af = AF_INET6; 1203 break; 1204 default: 1205 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1206 return -1; 1207 } 1208 need = sizeof(s5_req) + addrlen + 2; 1209 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1210 need++; 1211 if (have < need) 1212 return 0; 1213 buffer_consume(&c->input, sizeof(s5_req)); 1214 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1215 buffer_consume(&c->input, 1); /* host string length */ 1216 buffer_get(&c->input, (char *)&dest_addr, addrlen); 1217 buffer_get(&c->input, (char *)&dest_port, 2); 1218 dest_addr[addrlen] = '\0'; 1219 if (c->path != NULL) { 1220 xfree(c->path); 1221 c->path = NULL; 1222 } 1223 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1224 if (addrlen >= NI_MAXHOST) { 1225 error("channel %d: dynamic request: socks5 hostname " 1226 "\"%.100s\" too long", c->self, dest_addr); 1227 return -1; 1228 } 1229 c->path = xstrdup(dest_addr); 1230 } else { 1231 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1232 return -1; 1233 c->path = xstrdup(ntop); 1234 } 1235 c->host_port = ntohs(dest_port); 1236 1237 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1238 c->self, c->path, c->host_port, s5_req.command); 1239 1240 s5_rsp.version = 0x05; 1241 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1242 s5_rsp.reserved = 0; /* ignored */ 1243 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1244 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY; 1245 dest_port = 0; /* ignored */ 1246 1247 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp)); 1248 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr)); 1249 buffer_append(&c->output, &dest_port, sizeof(dest_port)); 1250 return 1; 1251} 1252 1253Channel * 1254channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect, 1255 int in, int out) 1256{ 1257 Channel *c; 1258 1259 debug("channel_connect_stdio_fwd %s:%d", host_to_connect, 1260 port_to_connect); 1261 1262 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out, 1263 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1264 0, "stdio-forward", /*nonblock*/0); 1265 1266 c->path = xstrdup(host_to_connect); 1267 c->host_port = port_to_connect; 1268 c->listening_port = 0; 1269 c->force_drain = 1; 1270 1271 channel_register_fds(c, in, out, -1, 0, 1, 0); 1272 port_open_helper(c, "direct-tcpip"); 1273 1274 return c; 1275} 1276 1277/* dynamic port forwarding */ 1278static void 1279channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset) 1280{ 1281 u_char *p; 1282 u_int have; 1283 int ret; 1284 1285 have = buffer_len(&c->input); 1286 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1287 /* buffer_dump(&c->input); */ 1288 /* check if the fixed size part of the packet is in buffer. */ 1289 if (have < 3) { 1290 /* need more */ 1291 FD_SET(c->sock, readset); 1292 return; 1293 } 1294 /* try to guess the protocol */ 1295 p = buffer_ptr(&c->input); 1296 switch (p[0]) { 1297 case 0x04: 1298 ret = channel_decode_socks4(c, readset, writeset); 1299 break; 1300 case 0x05: 1301 ret = channel_decode_socks5(c, readset, writeset); 1302 break; 1303 default: 1304 ret = -1; 1305 break; 1306 } 1307 if (ret < 0) { 1308 chan_mark_dead(c); 1309 } else if (ret == 0) { 1310 debug2("channel %d: pre_dynamic: need more", c->self); 1311 /* need more */ 1312 FD_SET(c->sock, readset); 1313 } else { 1314 /* switch to the next state */ 1315 c->type = SSH_CHANNEL_OPENING; 1316 port_open_helper(c, "direct-tcpip"); 1317 } 1318} 1319 1320/* This is our fake X11 server socket. */ 1321/* ARGSUSED */ 1322static void 1323channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset) 1324{ 1325 Channel *nc; 1326 struct sockaddr_storage addr; 1327 int newsock; 1328 socklen_t addrlen; 1329 char buf[16384], *remote_ipaddr; 1330 int remote_port; 1331 1332 if (FD_ISSET(c->sock, readset)) { 1333 debug("X11 connection requested."); 1334 addrlen = sizeof(addr); 1335 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1336 if (c->single_connection) { 1337 debug2("single_connection: closing X11 listener."); 1338 channel_close_fd(&c->sock); 1339 chan_mark_dead(c); 1340 } 1341 if (newsock < 0) { 1342 error("accept: %.100s", strerror(errno)); 1343 if (errno == EMFILE || errno == ENFILE) 1344 c->notbefore = time(NULL) + 1; 1345 return; 1346 } 1347 set_nodelay(newsock); 1348 remote_ipaddr = get_peer_ipaddr(newsock); 1349 remote_port = get_peer_port(newsock); 1350 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1351 remote_ipaddr, remote_port); 1352 1353 nc = channel_new("accepted x11 socket", 1354 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1355 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1356 if (compat20) { 1357 packet_start(SSH2_MSG_CHANNEL_OPEN); 1358 packet_put_cstring("x11"); 1359 packet_put_int(nc->self); 1360 packet_put_int(nc->local_window_max); 1361 packet_put_int(nc->local_maxpacket); 1362 /* originator ipaddr and port */ 1363 packet_put_cstring(remote_ipaddr); 1364 if (datafellows & SSH_BUG_X11FWD) { 1365 debug2("ssh2 x11 bug compat mode"); 1366 } else { 1367 packet_put_int(remote_port); 1368 } 1369 packet_send(); 1370 } else { 1371 packet_start(SSH_SMSG_X11_OPEN); 1372 packet_put_int(nc->self); 1373 if (packet_get_protocol_flags() & 1374 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1375 packet_put_cstring(buf); 1376 packet_send(); 1377 } 1378 xfree(remote_ipaddr); 1379 } 1380} 1381 1382static void 1383port_open_helper(Channel *c, char *rtype) 1384{ 1385 int direct; 1386 char buf[1024]; 1387 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1388 int remote_port = get_peer_port(c->sock); 1389 1390 if (remote_port == -1) { 1391 /* Fake addr/port to appease peers that validate it (Tectia) */ 1392 xfree(remote_ipaddr); 1393 remote_ipaddr = xstrdup("127.0.0.1"); 1394 remote_port = 65535; 1395 } 1396 1397 direct = (strcmp(rtype, "direct-tcpip") == 0); 1398 1399 snprintf(buf, sizeof buf, 1400 "%s: listening port %d for %.100s port %d, " 1401 "connect from %.200s port %d", 1402 rtype, c->listening_port, c->path, c->host_port, 1403 remote_ipaddr, remote_port); 1404 1405 xfree(c->remote_name); 1406 c->remote_name = xstrdup(buf); 1407 1408 if (compat20) { 1409 packet_start(SSH2_MSG_CHANNEL_OPEN); 1410 packet_put_cstring(rtype); 1411 packet_put_int(c->self); 1412 packet_put_int(c->local_window_max); 1413 packet_put_int(c->local_maxpacket); 1414 if (direct) { 1415 /* target host, port */ 1416 packet_put_cstring(c->path); 1417 packet_put_int(c->host_port); 1418 } else { 1419 /* listen address, port */ 1420 packet_put_cstring(c->path); 1421 packet_put_int(c->listening_port); 1422 } 1423 /* originator host and port */ 1424 packet_put_cstring(remote_ipaddr); 1425 packet_put_int((u_int)remote_port); 1426 packet_send(); 1427 } else { 1428 packet_start(SSH_MSG_PORT_OPEN); 1429 packet_put_int(c->self); 1430 packet_put_cstring(c->path); 1431 packet_put_int(c->host_port); 1432 if (packet_get_protocol_flags() & 1433 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1434 packet_put_cstring(c->remote_name); 1435 packet_send(); 1436 } 1437 xfree(remote_ipaddr); 1438} 1439 1440static void 1441channel_set_reuseaddr(int fd) 1442{ 1443 int on = 1; 1444 1445 /* 1446 * Set socket options. 1447 * Allow local port reuse in TIME_WAIT. 1448 */ 1449 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) 1450 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); 1451} 1452 1453/* 1454 * This socket is listening for connections to a forwarded TCP/IP port. 1455 */ 1456/* ARGSUSED */ 1457static void 1458channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset) 1459{ 1460 Channel *nc; 1461 struct sockaddr_storage addr; 1462 int newsock, nextstate; 1463 socklen_t addrlen; 1464 char *rtype; 1465 1466 if (FD_ISSET(c->sock, readset)) { 1467 debug("Connection to port %d forwarding " 1468 "to %.100s port %d requested.", 1469 c->listening_port, c->path, c->host_port); 1470 1471 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1472 nextstate = SSH_CHANNEL_OPENING; 1473 rtype = "forwarded-tcpip"; 1474 } else { 1475 if (c->host_port == 0) { 1476 nextstate = SSH_CHANNEL_DYNAMIC; 1477 rtype = "dynamic-tcpip"; 1478 } else { 1479 nextstate = SSH_CHANNEL_OPENING; 1480 rtype = "direct-tcpip"; 1481 } 1482 } 1483 1484 addrlen = sizeof(addr); 1485 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1486 if (newsock < 0) { 1487 error("accept: %.100s", strerror(errno)); 1488 if (errno == EMFILE || errno == ENFILE) 1489 c->notbefore = time(NULL) + 1; 1490 return; 1491 } 1492 set_nodelay(newsock); 1493 nc = channel_new(rtype, nextstate, newsock, newsock, -1, 1494 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1495 nc->listening_port = c->listening_port; 1496 nc->host_port = c->host_port; 1497 if (c->path != NULL) 1498 nc->path = xstrdup(c->path); 1499 1500 if (nextstate != SSH_CHANNEL_DYNAMIC) 1501 port_open_helper(nc, rtype); 1502 } 1503} 1504 1505/* 1506 * This is the authentication agent socket listening for connections from 1507 * clients. 1508 */ 1509/* ARGSUSED */ 1510static void 1511channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset) 1512{ 1513 Channel *nc; 1514 int newsock; 1515 struct sockaddr_storage addr; 1516 socklen_t addrlen; 1517 1518 if (FD_ISSET(c->sock, readset)) { 1519 addrlen = sizeof(addr); 1520 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1521 if (newsock < 0) { 1522 error("accept from auth socket: %.100s", 1523 strerror(errno)); 1524 if (errno == EMFILE || errno == ENFILE) 1525 c->notbefore = time(NULL) + 1; 1526 return; 1527 } 1528 nc = channel_new("accepted auth socket", 1529 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1530 c->local_window_max, c->local_maxpacket, 1531 0, "accepted auth socket", 1); 1532 if (compat20) { 1533 packet_start(SSH2_MSG_CHANNEL_OPEN); 1534 packet_put_cstring("auth-agent@openssh.com"); 1535 packet_put_int(nc->self); 1536 packet_put_int(c->local_window_max); 1537 packet_put_int(c->local_maxpacket); 1538 } else { 1539 packet_start(SSH_SMSG_AGENT_OPEN); 1540 packet_put_int(nc->self); 1541 } 1542 packet_send(); 1543 } 1544} 1545 1546/* ARGSUSED */ 1547static void 1548channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset) 1549{ 1550 int err = 0, sock; 1551 socklen_t sz = sizeof(err); 1552 1553 if (FD_ISSET(c->sock, writeset)) { 1554 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { 1555 err = errno; 1556 error("getsockopt SO_ERROR failed"); 1557 } 1558 if (err == 0) { 1559 debug("channel %d: connected to %s port %d", 1560 c->self, c->connect_ctx.host, c->connect_ctx.port); 1561 channel_connect_ctx_free(&c->connect_ctx); 1562 c->type = SSH_CHANNEL_OPEN; 1563 if (compat20) { 1564 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1565 packet_put_int(c->remote_id); 1566 packet_put_int(c->self); 1567 packet_put_int(c->local_window); 1568 packet_put_int(c->local_maxpacket); 1569 } else { 1570 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1571 packet_put_int(c->remote_id); 1572 packet_put_int(c->self); 1573 } 1574 } else { 1575 debug("channel %d: connection failed: %s", 1576 c->self, strerror(err)); 1577 /* Try next address, if any */ 1578 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1579 close(c->sock); 1580 c->sock = c->rfd = c->wfd = sock; 1581 channel_max_fd = channel_find_maxfd(); 1582 return; 1583 } 1584 /* Exhausted all addresses */ 1585 error("connect_to %.100s port %d: failed.", 1586 c->connect_ctx.host, c->connect_ctx.port); 1587 channel_connect_ctx_free(&c->connect_ctx); 1588 if (compat20) { 1589 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1590 packet_put_int(c->remote_id); 1591 packet_put_int(SSH2_OPEN_CONNECT_FAILED); 1592 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1593 packet_put_cstring(strerror(err)); 1594 packet_put_cstring(""); 1595 } 1596 } else { 1597 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1598 packet_put_int(c->remote_id); 1599 } 1600 chan_mark_dead(c); 1601 } 1602 packet_send(); 1603 } 1604} 1605 1606/* ARGSUSED */ 1607static int 1608channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset) 1609{ 1610 char buf[CHAN_RBUF]; 1611 int len, force; 1612 1613 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 1614 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) { 1615 errno = 0; 1616 len = read(c->rfd, buf, sizeof(buf)); 1617 if (len < 0 && (errno == EINTR || 1618 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 1619 return 1; 1620#ifndef PTY_ZEROREAD 1621 if (len <= 0) { 1622#else 1623 if ((!c->isatty && len <= 0) || 1624 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) { 1625#endif 1626 debug2("channel %d: read<=0 rfd %d len %d", 1627 c->self, c->rfd, len); 1628 if (c->type != SSH_CHANNEL_OPEN) { 1629 debug2("channel %d: not open", c->self); 1630 chan_mark_dead(c); 1631 return -1; 1632 } else if (compat13) { 1633 buffer_clear(&c->output); 1634 c->type = SSH_CHANNEL_INPUT_DRAINING; 1635 debug2("channel %d: input draining.", c->self); 1636 } else { 1637 chan_read_failed(c); 1638 } 1639 return -1; 1640 } 1641 if (c->input_filter != NULL) { 1642 if (c->input_filter(c, buf, len) == -1) { 1643 debug2("channel %d: filter stops", c->self); 1644 chan_read_failed(c); 1645 } 1646 } else if (c->datagram) { 1647 buffer_put_string(&c->input, buf, len); 1648 } else { 1649 buffer_append(&c->input, buf, len); 1650 } 1651 } 1652 return 1; 1653} 1654 1655/* ARGSUSED */ 1656static int 1657channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset) 1658{ 1659 struct termios tio; 1660 u_char *data = NULL, *buf; 1661 u_int dlen, olen = 0; 1662 int len; 1663 1664 /* Send buffered output data to the socket. */ 1665 if (c->wfd != -1 && 1666 FD_ISSET(c->wfd, writeset) && 1667 buffer_len(&c->output) > 0) { 1668 olen = buffer_len(&c->output); 1669 if (c->output_filter != NULL) { 1670 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) { 1671 debug2("channel %d: filter stops", c->self); 1672 if (c->type != SSH_CHANNEL_OPEN) 1673 chan_mark_dead(c); 1674 else 1675 chan_write_failed(c); 1676 return -1; 1677 } 1678 } else if (c->datagram) { 1679 buf = data = buffer_get_string(&c->output, &dlen); 1680 } else { 1681 buf = data = buffer_ptr(&c->output); 1682 dlen = buffer_len(&c->output); 1683 } 1684 1685 if (c->datagram) { 1686 /* ignore truncated writes, datagrams might get lost */ 1687 len = write(c->wfd, buf, dlen); 1688 xfree(data); 1689 if (len < 0 && (errno == EINTR || errno == EAGAIN || 1690 errno == EWOULDBLOCK)) 1691 return 1; 1692 if (len <= 0) { 1693 if (c->type != SSH_CHANNEL_OPEN) 1694 chan_mark_dead(c); 1695 else 1696 chan_write_failed(c); 1697 return -1; 1698 } 1699 goto out; 1700 } 1701#ifdef _AIX 1702 /* XXX: Later AIX versions can't push as much data to tty */ 1703 if (compat20 && c->wfd_isatty) 1704 dlen = MIN(dlen, 8*1024); 1705#endif 1706 1707 len = write(c->wfd, buf, dlen); 1708 if (len < 0 && 1709 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 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#ifndef BROKEN_TCGETATTR_ICANON 1726 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') { 1727 if (tcgetattr(c->wfd, &tio) == 0 && 1728 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 1729 /* 1730 * Simulate echo to reduce the impact of 1731 * traffic analysis. We need to match the 1732 * size of a SSH2_MSG_CHANNEL_DATA message 1733 * (4 byte channel id + buf) 1734 */ 1735 packet_send_ignore(4 + len); 1736 packet_send(); 1737 } 1738 } 1739#endif 1740 buffer_consume(&c->output, len); 1741 } 1742 out: 1743 if (compat20 && olen > 0) 1744 c->local_consumed += olen - buffer_len(&c->output); 1745 return 1; 1746} 1747 1748static int 1749channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset) 1750{ 1751 char buf[CHAN_RBUF]; 1752 int len; 1753 1754/** XXX handle drain efd, too */ 1755 if (c->efd != -1) { 1756 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1757 FD_ISSET(c->efd, writeset) && 1758 buffer_len(&c->extended) > 0) { 1759 len = write(c->efd, buffer_ptr(&c->extended), 1760 buffer_len(&c->extended)); 1761 debug2("channel %d: written %d to efd %d", 1762 c->self, len, c->efd); 1763 if (len < 0 && (errno == EINTR || errno == EAGAIN || 1764 errno == EWOULDBLOCK)) 1765 return 1; 1766 if (len <= 0) { 1767 debug2("channel %d: closing write-efd %d", 1768 c->self, c->efd); 1769 channel_close_fd(&c->efd); 1770 } else { 1771 buffer_consume(&c->extended, len); 1772 c->local_consumed += len; 1773 } 1774 } else if (c->efd != -1 && 1775 (c->extended_usage == CHAN_EXTENDED_READ || 1776 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1777 (c->detach_close || FD_ISSET(c->efd, readset))) { 1778 len = read(c->efd, buf, sizeof(buf)); 1779 debug2("channel %d: read %d from efd %d", 1780 c->self, len, c->efd); 1781 if (len < 0 && (errno == EINTR || ((errno == EAGAIN || 1782 errno == EWOULDBLOCK) && !c->detach_close))) 1783 return 1; 1784 if (len <= 0) { 1785 debug2("channel %d: closing read-efd %d", 1786 c->self, c->efd); 1787 channel_close_fd(&c->efd); 1788 } else { 1789 if (c->extended_usage == CHAN_EXTENDED_IGNORE) { 1790 debug3("channel %d: discard efd", 1791 c->self); 1792 } else 1793 buffer_append(&c->extended, buf, len); 1794 } 1795 } 1796 } 1797 return 1; 1798} 1799 1800static int 1801channel_check_window(Channel *c) 1802{ 1803 if (c->type == SSH_CHANNEL_OPEN && 1804 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 1805 ((c->local_window_max - c->local_window > 1806 c->local_maxpacket*3) || 1807 c->local_window < c->local_window_max/2) && 1808 c->local_consumed > 0) { 1809 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 1810 packet_put_int(c->remote_id); 1811 packet_put_int(c->local_consumed); 1812 packet_send(); 1813 debug2("channel %d: window %d sent adjust %d", 1814 c->self, c->local_window, 1815 c->local_consumed); 1816 c->local_window += c->local_consumed; 1817 c->local_consumed = 0; 1818 } 1819 return 1; 1820} 1821 1822static void 1823channel_post_open(Channel *c, fd_set *readset, fd_set *writeset) 1824{ 1825 channel_handle_rfd(c, readset, writeset); 1826 channel_handle_wfd(c, readset, writeset); 1827 if (!compat20) 1828 return; 1829 channel_handle_efd(c, readset, writeset); 1830 channel_check_window(c); 1831} 1832 1833static u_int 1834read_mux(Channel *c, u_int need) 1835{ 1836 char buf[CHAN_RBUF]; 1837 int len; 1838 u_int rlen; 1839 1840 if (buffer_len(&c->input) < need) { 1841 rlen = need - buffer_len(&c->input); 1842 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF)); 1843 if (len <= 0) { 1844 if (errno != EINTR && errno != EAGAIN) { 1845 debug2("channel %d: ctl read<=0 rfd %d len %d", 1846 c->self, c->rfd, len); 1847 chan_read_failed(c); 1848 return 0; 1849 } 1850 } else 1851 buffer_append(&c->input, buf, len); 1852 } 1853 return buffer_len(&c->input); 1854} 1855 1856static void 1857channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1858{ 1859 u_int need; 1860 ssize_t len; 1861 1862 if (!compat20) 1863 fatal("%s: entered with !compat20", __func__); 1864 1865 if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) && 1866 (c->istate == CHAN_INPUT_OPEN || 1867 c->istate == CHAN_INPUT_WAIT_DRAIN)) { 1868 /* 1869 * Don't not read past the precise end of packets to 1870 * avoid disrupting fd passing. 1871 */ 1872 if (read_mux(c, 4) < 4) /* read header */ 1873 return; 1874 need = get_u32(buffer_ptr(&c->input)); 1875#define CHANNEL_MUX_MAX_PACKET (256 * 1024) 1876 if (need > CHANNEL_MUX_MAX_PACKET) { 1877 debug2("channel %d: packet too big %u > %u", 1878 c->self, CHANNEL_MUX_MAX_PACKET, need); 1879 chan_rcvd_oclose(c); 1880 return; 1881 } 1882 if (read_mux(c, need + 4) < need + 4) /* read body */ 1883 return; 1884 if (c->mux_rcb(c) != 0) { 1885 debug("channel %d: mux_rcb failed", c->self); 1886 chan_mark_dead(c); 1887 return; 1888 } 1889 } 1890 1891 if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) && 1892 buffer_len(&c->output) > 0) { 1893 len = write(c->wfd, buffer_ptr(&c->output), 1894 buffer_len(&c->output)); 1895 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1896 return; 1897 if (len <= 0) { 1898 chan_mark_dead(c); 1899 return; 1900 } 1901 buffer_consume(&c->output, len); 1902 } 1903} 1904 1905static void 1906channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset) 1907{ 1908 Channel *nc; 1909 struct sockaddr_storage addr; 1910 socklen_t addrlen; 1911 int newsock; 1912 uid_t euid; 1913 gid_t egid; 1914 1915 if (!FD_ISSET(c->sock, readset)) 1916 return; 1917 1918 debug("multiplexing control connection"); 1919 1920 /* 1921 * Accept connection on control socket 1922 */ 1923 memset(&addr, 0, sizeof(addr)); 1924 addrlen = sizeof(addr); 1925 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 1926 &addrlen)) == -1) { 1927 error("%s accept: %s", __func__, strerror(errno)); 1928 if (errno == EMFILE || errno == ENFILE) 1929 c->notbefore = time(NULL) + 1; 1930 return; 1931 } 1932 1933 if (getpeereid(newsock, &euid, &egid) < 0) { 1934 error("%s getpeereid failed: %s", __func__, 1935 strerror(errno)); 1936 close(newsock); 1937 return; 1938 } 1939 if ((euid != 0) && (getuid() != euid)) { 1940 error("multiplex uid mismatch: peer euid %u != uid %u", 1941 (u_int)euid, (u_int)getuid()); 1942 close(newsock); 1943 return; 1944 } 1945 nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT, 1946 newsock, newsock, -1, c->local_window_max, 1947 c->local_maxpacket, 0, "mux-control", 1); 1948 nc->mux_rcb = c->mux_rcb; 1949 debug3("%s: new mux channel %d fd %d", __func__, 1950 nc->self, nc->sock); 1951 /* establish state */ 1952 nc->mux_rcb(nc); 1953 /* mux state transitions must not elicit protocol messages */ 1954 nc->flags |= CHAN_LOCAL; 1955} 1956 1957/* ARGSUSED */ 1958static void 1959channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset) 1960{ 1961 int len; 1962 1963 /* Send buffered output data to the socket. */ 1964 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { 1965 len = write(c->sock, buffer_ptr(&c->output), 1966 buffer_len(&c->output)); 1967 if (len <= 0) 1968 buffer_clear(&c->output); 1969 else 1970 buffer_consume(&c->output, len); 1971 } 1972} 1973 1974static void 1975channel_handler_init_20(void) 1976{ 1977 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 1978 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 1979 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 1980 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 1981 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 1982 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 1983 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 1984 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 1985 channel_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 1986 channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 1987 1988 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 1989 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 1990 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 1991 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 1992 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 1993 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 1994 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 1995 channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 1996 channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 1997} 1998 1999static void 2000channel_handler_init_13(void) 2001{ 2002 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; 2003 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; 2004 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2005 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2006 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2007 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; 2008 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; 2009 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2010 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2011 2012 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2013 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2014 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2015 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2016 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; 2017 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2018 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2019} 2020 2021static void 2022channel_handler_init_15(void) 2023{ 2024 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2025 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2026 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2027 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2028 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2029 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2030 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2031 2032 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2033 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2034 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2035 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2036 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2037 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2038} 2039 2040static void 2041channel_handler_init(void) 2042{ 2043 int i; 2044 2045 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { 2046 channel_pre[i] = NULL; 2047 channel_post[i] = NULL; 2048 } 2049 if (compat20) 2050 channel_handler_init_20(); 2051 else if (compat13) 2052 channel_handler_init_13(); 2053 else 2054 channel_handler_init_15(); 2055} 2056 2057/* gc dead channels */ 2058static void 2059channel_garbage_collect(Channel *c) 2060{ 2061 if (c == NULL) 2062 return; 2063 if (c->detach_user != NULL) { 2064 if (!chan_is_dead(c, c->detach_close)) 2065 return; 2066 debug2("channel %d: gc: notify user", c->self); 2067 c->detach_user(c->self, NULL); 2068 /* if we still have a callback */ 2069 if (c->detach_user != NULL) 2070 return; 2071 debug2("channel %d: gc: user detached", c->self); 2072 } 2073 if (!chan_is_dead(c, 1)) 2074 return; 2075 debug2("channel %d: garbage collecting", c->self); 2076 channel_free(c); 2077} 2078 2079static void 2080channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset, 2081 time_t *unpause_secs) 2082{ 2083 static int did_init = 0; 2084 u_int i, oalloc; 2085 Channel *c; 2086 time_t now; 2087 2088 if (!did_init) { 2089 channel_handler_init(); 2090 did_init = 1; 2091 } 2092 now = time(NULL); 2093 if (unpause_secs != NULL) 2094 *unpause_secs = 0; 2095 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) { 2096 c = channels[i]; 2097 if (c == NULL) 2098 continue; 2099 if (c->delayed) { 2100 if (ftab == channel_pre) 2101 c->delayed = 0; 2102 else 2103 continue; 2104 } 2105 if (ftab[c->type] != NULL) { 2106 /* 2107 * Run handlers that are not paused. 2108 */ 2109 if (c->notbefore <= now) 2110 (*ftab[c->type])(c, readset, writeset); 2111 else if (unpause_secs != NULL) { 2112 /* 2113 * Collect the time that the earliest 2114 * channel comes off pause. 2115 */ 2116 debug3("%s: chan %d: skip for %d more seconds", 2117 __func__, c->self, 2118 (int)(c->notbefore - now)); 2119 if (*unpause_secs == 0 || 2120 (c->notbefore - now) < *unpause_secs) 2121 *unpause_secs = c->notbefore - now; 2122 } 2123 } 2124 channel_garbage_collect(c); 2125 } 2126 if (unpause_secs != NULL && *unpause_secs != 0) 2127 debug3("%s: first channel unpauses in %d seconds", 2128 __func__, (int)*unpause_secs); 2129} 2130 2131/* 2132 * Allocate/update select bitmasks and add any bits relevant to channels in 2133 * select bitmasks. 2134 */ 2135void 2136channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, 2137 u_int *nallocp, time_t *minwait_secs, int rekeying) 2138{ 2139 u_int n, sz, nfdset; 2140 2141 n = MAX(*maxfdp, channel_max_fd); 2142 2143 nfdset = howmany(n+1, NFDBITS); 2144 /* Explicitly test here, because xrealloc isn't always called */ 2145 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask)) 2146 fatal("channel_prepare_select: max_fd (%d) is too large", n); 2147 sz = nfdset * sizeof(fd_mask); 2148 2149 /* perhaps check sz < nalloc/2 and shrink? */ 2150 if (*readsetp == NULL || sz > *nallocp) { 2151 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask)); 2152 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask)); 2153 *nallocp = sz; 2154 } 2155 *maxfdp = n; 2156 memset(*readsetp, 0, sz); 2157 memset(*writesetp, 0, sz); 2158 2159 if (!rekeying) 2160 channel_handler(channel_pre, *readsetp, *writesetp, 2161 minwait_secs); 2162} 2163 2164/* 2165 * After select, perform any appropriate operations for channels which have 2166 * events pending. 2167 */ 2168void 2169channel_after_select(fd_set *readset, fd_set *writeset) 2170{ 2171 channel_handler(channel_post, readset, writeset, NULL); 2172} 2173 2174 2175/* If there is data to send to the connection, enqueue some of it now. */ 2176void 2177channel_output_poll(void) 2178{ 2179 Channel *c; 2180 u_int i, len; 2181 2182 for (i = 0; i < channels_alloc; i++) { 2183 c = channels[i]; 2184 if (c == NULL) 2185 continue; 2186 2187 /* 2188 * We are only interested in channels that can have buffered 2189 * incoming data. 2190 */ 2191 if (compat13) { 2192 if (c->type != SSH_CHANNEL_OPEN && 2193 c->type != SSH_CHANNEL_INPUT_DRAINING) 2194 continue; 2195 } else { 2196 if (c->type != SSH_CHANNEL_OPEN) 2197 continue; 2198 } 2199 if (compat20 && 2200 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2201 /* XXX is this true? */ 2202 debug3("channel %d: will not send data after close", c->self); 2203 continue; 2204 } 2205 2206 /* Get the amount of buffered data for this channel. */ 2207 if ((c->istate == CHAN_INPUT_OPEN || 2208 c->istate == CHAN_INPUT_WAIT_DRAIN) && 2209 (len = buffer_len(&c->input)) > 0) { 2210 if (c->datagram) { 2211 if (len > 0) { 2212 u_char *data; 2213 u_int dlen; 2214 2215 data = buffer_get_string(&c->input, 2216 &dlen); 2217 if (dlen > c->remote_window || 2218 dlen > c->remote_maxpacket) { 2219 debug("channel %d: datagram " 2220 "too big for channel", 2221 c->self); 2222 xfree(data); 2223 continue; 2224 } 2225 packet_start(SSH2_MSG_CHANNEL_DATA); 2226 packet_put_int(c->remote_id); 2227 packet_put_string(data, dlen); 2228 packet_send(); 2229 c->remote_window -= dlen + 4; 2230 xfree(data); 2231 } 2232 continue; 2233 } 2234 /* 2235 * Send some data for the other side over the secure 2236 * connection. 2237 */ 2238 if (compat20) { 2239 if (len > c->remote_window) 2240 len = c->remote_window; 2241 if (len > c->remote_maxpacket) 2242 len = c->remote_maxpacket; 2243 } else { 2244 if (packet_is_interactive()) { 2245 if (len > 1024) 2246 len = 512; 2247 } else { 2248 /* Keep the packets at reasonable size. */ 2249 if (len > packet_get_maxsize()/2) 2250 len = packet_get_maxsize()/2; 2251 } 2252 } 2253 if (len > 0) { 2254 packet_start(compat20 ? 2255 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); 2256 packet_put_int(c->remote_id); 2257 packet_put_string(buffer_ptr(&c->input), len); 2258 packet_send(); 2259 buffer_consume(&c->input, len); 2260 c->remote_window -= len; 2261 } 2262 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2263 if (compat13) 2264 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); 2265 /* 2266 * input-buffer is empty and read-socket shutdown: 2267 * tell peer, that we will not send more data: send IEOF. 2268 * hack for extended data: delay EOF if EFD still in use. 2269 */ 2270 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2271 debug2("channel %d: ibuf_empty delayed efd %d/(%d)", 2272 c->self, c->efd, buffer_len(&c->extended)); 2273 else 2274 chan_ibuf_empty(c); 2275 } 2276 /* Send extended data, i.e. stderr */ 2277 if (compat20 && 2278 !(c->flags & CHAN_EOF_SENT) && 2279 c->remote_window > 0 && 2280 (len = buffer_len(&c->extended)) > 0 && 2281 c->extended_usage == CHAN_EXTENDED_READ) { 2282 debug2("channel %d: rwin %u elen %u euse %d", 2283 c->self, c->remote_window, buffer_len(&c->extended), 2284 c->extended_usage); 2285 if (len > c->remote_window) 2286 len = c->remote_window; 2287 if (len > c->remote_maxpacket) 2288 len = c->remote_maxpacket; 2289 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); 2290 packet_put_int(c->remote_id); 2291 packet_put_int(SSH2_EXTENDED_DATA_STDERR); 2292 packet_put_string(buffer_ptr(&c->extended), len); 2293 packet_send(); 2294 buffer_consume(&c->extended, len); 2295 c->remote_window -= len; 2296 debug2("channel %d: sent ext data %d", c->self, len); 2297 } 2298 } 2299} 2300 2301 2302/* -- protocol input */ 2303 2304/* ARGSUSED */ 2305void 2306channel_input_data(int type, u_int32_t seq, void *ctxt) 2307{ 2308 int id; 2309 char *data; 2310 u_int data_len, win_len; 2311 Channel *c; 2312 2313 /* Get the channel number and verify it. */ 2314 id = packet_get_int(); 2315 c = channel_lookup(id); 2316 if (c == NULL) 2317 packet_disconnect("Received data for nonexistent channel %d.", id); 2318 2319 /* Ignore any data for non-open channels (might happen on close) */ 2320 if (c->type != SSH_CHANNEL_OPEN && 2321 c->type != SSH_CHANNEL_X11_OPEN) 2322 return; 2323 2324 /* Get the data. */ 2325 data = packet_get_string_ptr(&data_len); 2326 win_len = data_len; 2327 if (c->datagram) 2328 win_len += 4; /* string length header */ 2329 2330 /* 2331 * Ignore data for protocol > 1.3 if output end is no longer open. 2332 * For protocol 2 the sending side is reducing its window as it sends 2333 * data, so we must 'fake' consumption of the data in order to ensure 2334 * that window updates are sent back. Otherwise the connection might 2335 * deadlock. 2336 */ 2337 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { 2338 if (compat20) { 2339 c->local_window -= win_len; 2340 c->local_consumed += win_len; 2341 } 2342 return; 2343 } 2344 2345 if (compat20) { 2346 if (win_len > c->local_maxpacket) { 2347 logit("channel %d: rcvd big packet %d, maxpack %d", 2348 c->self, win_len, c->local_maxpacket); 2349 } 2350 if (win_len > c->local_window) { 2351 logit("channel %d: rcvd too much data %d, win %d", 2352 c->self, win_len, c->local_window); 2353 return; 2354 } 2355 c->local_window -= win_len; 2356 } 2357 if (c->datagram) 2358 buffer_put_string(&c->output, data, data_len); 2359 else 2360 buffer_append(&c->output, data, data_len); 2361 packet_check_eom(); 2362} 2363 2364/* ARGSUSED */ 2365void 2366channel_input_extended_data(int type, u_int32_t seq, void *ctxt) 2367{ 2368 int id; 2369 char *data; 2370 u_int data_len, tcode; 2371 Channel *c; 2372 2373 /* Get the channel number and verify it. */ 2374 id = packet_get_int(); 2375 c = channel_lookup(id); 2376 2377 if (c == NULL) 2378 packet_disconnect("Received extended_data for bad channel %d.", id); 2379 if (c->type != SSH_CHANNEL_OPEN) { 2380 logit("channel %d: ext data for non open", id); 2381 return; 2382 } 2383 if (c->flags & CHAN_EOF_RCVD) { 2384 if (datafellows & SSH_BUG_EXTEOF) 2385 debug("channel %d: accepting ext data after eof", id); 2386 else 2387 packet_disconnect("Received extended_data after EOF " 2388 "on channel %d.", id); 2389 } 2390 tcode = packet_get_int(); 2391 if (c->efd == -1 || 2392 c->extended_usage != CHAN_EXTENDED_WRITE || 2393 tcode != SSH2_EXTENDED_DATA_STDERR) { 2394 logit("channel %d: bad ext data", c->self); 2395 return; 2396 } 2397 data = packet_get_string(&data_len); 2398 packet_check_eom(); 2399 if (data_len > c->local_window) { 2400 logit("channel %d: rcvd too much extended_data %d, win %d", 2401 c->self, data_len, c->local_window); 2402 xfree(data); 2403 return; 2404 } 2405 debug2("channel %d: rcvd ext data %d", c->self, data_len); 2406 c->local_window -= data_len; 2407 buffer_append(&c->extended, data, data_len); 2408 xfree(data); 2409} 2410 2411/* ARGSUSED */ 2412void 2413channel_input_ieof(int type, u_int32_t seq, void *ctxt) 2414{ 2415 int id; 2416 Channel *c; 2417 2418 id = packet_get_int(); 2419 packet_check_eom(); 2420 c = channel_lookup(id); 2421 if (c == NULL) 2422 packet_disconnect("Received ieof for nonexistent channel %d.", id); 2423 chan_rcvd_ieof(c); 2424 2425 /* XXX force input close */ 2426 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 2427 debug("channel %d: FORCE input drain", c->self); 2428 c->istate = CHAN_INPUT_WAIT_DRAIN; 2429 if (buffer_len(&c->input) == 0) 2430 chan_ibuf_empty(c); 2431 } 2432 2433} 2434 2435/* ARGSUSED */ 2436void 2437channel_input_close(int type, u_int32_t seq, void *ctxt) 2438{ 2439 int id; 2440 Channel *c; 2441 2442 id = packet_get_int(); 2443 packet_check_eom(); 2444 c = channel_lookup(id); 2445 if (c == NULL) 2446 packet_disconnect("Received close for nonexistent channel %d.", id); 2447 2448 /* 2449 * Send a confirmation that we have closed the channel and no more 2450 * data is coming for it. 2451 */ 2452 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); 2453 packet_put_int(c->remote_id); 2454 packet_send(); 2455 2456 /* 2457 * If the channel is in closed state, we have sent a close request, 2458 * and the other side will eventually respond with a confirmation. 2459 * Thus, we cannot free the channel here, because then there would be 2460 * no-one to receive the confirmation. The channel gets freed when 2461 * the confirmation arrives. 2462 */ 2463 if (c->type != SSH_CHANNEL_CLOSED) { 2464 /* 2465 * Not a closed channel - mark it as draining, which will 2466 * cause it to be freed later. 2467 */ 2468 buffer_clear(&c->input); 2469 c->type = SSH_CHANNEL_OUTPUT_DRAINING; 2470 } 2471} 2472 2473/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ 2474/* ARGSUSED */ 2475void 2476channel_input_oclose(int type, u_int32_t seq, void *ctxt) 2477{ 2478 int id = packet_get_int(); 2479 Channel *c = channel_lookup(id); 2480 2481 packet_check_eom(); 2482 if (c == NULL) 2483 packet_disconnect("Received oclose for nonexistent channel %d.", id); 2484 chan_rcvd_oclose(c); 2485} 2486 2487/* ARGSUSED */ 2488void 2489channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) 2490{ 2491 int id = packet_get_int(); 2492 Channel *c = channel_lookup(id); 2493 2494 packet_check_eom(); 2495 if (c == NULL) 2496 packet_disconnect("Received close confirmation for " 2497 "out-of-range channel %d.", id); 2498 if (c->type != SSH_CHANNEL_CLOSED) 2499 packet_disconnect("Received close confirmation for " 2500 "non-closed channel %d (type %d).", id, c->type); 2501 channel_free(c); 2502} 2503 2504/* ARGSUSED */ 2505void 2506channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) 2507{ 2508 int id, remote_id; 2509 Channel *c; 2510 2511 id = packet_get_int(); 2512 c = channel_lookup(id); 2513 2514 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2515 packet_disconnect("Received open confirmation for " 2516 "non-opening channel %d.", id); 2517 remote_id = packet_get_int(); 2518 /* Record the remote channel number and mark that the channel is now open. */ 2519 c->remote_id = remote_id; 2520 c->type = SSH_CHANNEL_OPEN; 2521 2522 if (compat20) { 2523 c->remote_window = packet_get_int(); 2524 c->remote_maxpacket = packet_get_int(); 2525 if (c->open_confirm) { 2526 debug2("callback start"); 2527 c->open_confirm(c->self, 1, c->open_confirm_ctx); 2528 debug2("callback done"); 2529 } 2530 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 2531 c->remote_window, c->remote_maxpacket); 2532 } 2533 packet_check_eom(); 2534} 2535 2536static char * 2537reason2txt(int reason) 2538{ 2539 switch (reason) { 2540 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 2541 return "administratively prohibited"; 2542 case SSH2_OPEN_CONNECT_FAILED: 2543 return "connect failed"; 2544 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 2545 return "unknown channel type"; 2546 case SSH2_OPEN_RESOURCE_SHORTAGE: 2547 return "resource shortage"; 2548 } 2549 return "unknown reason"; 2550} 2551 2552/* ARGSUSED */ 2553void 2554channel_input_open_failure(int type, u_int32_t seq, void *ctxt) 2555{ 2556 int id, reason; 2557 char *msg = NULL, *lang = NULL; 2558 Channel *c; 2559 2560 id = packet_get_int(); 2561 c = channel_lookup(id); 2562 2563 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2564 packet_disconnect("Received open failure for " 2565 "non-opening channel %d.", id); 2566 if (compat20) { 2567 reason = packet_get_int(); 2568 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 2569 msg = packet_get_string(NULL); 2570 lang = packet_get_string(NULL); 2571 } 2572 logit("channel %d: open failed: %s%s%s", id, 2573 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 2574 if (msg != NULL) 2575 xfree(msg); 2576 if (lang != NULL) 2577 xfree(lang); 2578 if (c->open_confirm) { 2579 debug2("callback start"); 2580 c->open_confirm(c->self, 0, c->open_confirm_ctx); 2581 debug2("callback done"); 2582 } 2583 } 2584 packet_check_eom(); 2585 /* Schedule the channel for cleanup/deletion. */ 2586 chan_mark_dead(c); 2587} 2588 2589/* ARGSUSED */ 2590void 2591channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) 2592{ 2593 Channel *c; 2594 int id; 2595 u_int adjust; 2596 2597 if (!compat20) 2598 return; 2599 2600 /* Get the channel number and verify it. */ 2601 id = packet_get_int(); 2602 c = channel_lookup(id); 2603 2604 if (c == NULL) { 2605 logit("Received window adjust for non-open channel %d.", id); 2606 return; 2607 } 2608 adjust = packet_get_int(); 2609 packet_check_eom(); 2610 debug2("channel %d: rcvd adjust %u", id, adjust); 2611 c->remote_window += adjust; 2612} 2613 2614/* ARGSUSED */ 2615void 2616channel_input_port_open(int type, u_int32_t seq, void *ctxt) 2617{ 2618 Channel *c = NULL; 2619 u_short host_port; 2620 char *host, *originator_string; 2621 int remote_id; 2622 2623 remote_id = packet_get_int(); 2624 host = packet_get_string(NULL); 2625 host_port = packet_get_int(); 2626 2627 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 2628 originator_string = packet_get_string(NULL); 2629 } else { 2630 originator_string = xstrdup("unknown (remote did not supply name)"); 2631 } 2632 packet_check_eom(); 2633 c = channel_connect_to(host, host_port, 2634 "connected socket", originator_string); 2635 xfree(originator_string); 2636 xfree(host); 2637 if (c == NULL) { 2638 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 2639 packet_put_int(remote_id); 2640 packet_send(); 2641 } else 2642 c->remote_id = remote_id; 2643} 2644 2645/* ARGSUSED */ 2646void 2647channel_input_status_confirm(int type, u_int32_t seq, void *ctxt) 2648{ 2649 Channel *c; 2650 struct channel_confirm *cc; 2651 int id; 2652 2653 /* Reset keepalive timeout */ 2654 packet_set_alive_timeouts(0); 2655 2656 id = packet_get_int(); 2657 packet_check_eom(); 2658 2659 debug2("channel_input_status_confirm: type %d id %d", type, id); 2660 2661 if ((c = channel_lookup(id)) == NULL) { 2662 logit("channel_input_status_confirm: %d: unknown", id); 2663 return; 2664 } 2665 ; 2666 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 2667 return; 2668 cc->cb(type, c, cc->ctx); 2669 TAILQ_REMOVE(&c->status_confirms, cc, entry); 2670 bzero(cc, sizeof(*cc)); 2671 xfree(cc); 2672} 2673 2674/* -- tcp forwarding */ 2675 2676void 2677channel_set_af(int af) 2678{ 2679 IPv4or6 = af; 2680} 2681 2682 2683/* 2684 * Determine whether or not a port forward listens to loopback, the 2685 * specified address or wildcard. On the client, a specified bind 2686 * address will always override gateway_ports. On the server, a 2687 * gateway_ports of 1 (``yes'') will override the client's specification 2688 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 2689 * will bind to whatever address the client asked for. 2690 * 2691 * Special-case listen_addrs are: 2692 * 2693 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 2694 * "" (empty string), "*" -> wildcard v4/v6 2695 * "localhost" -> loopback v4/v6 2696 */ 2697static const char * 2698channel_fwd_bind_addr(const char *listen_addr, int *wildcardp, 2699 int is_client, int gateway_ports) 2700{ 2701 const char *addr = NULL; 2702 int wildcard = 0; 2703 2704 if (listen_addr == NULL) { 2705 /* No address specified: default to gateway_ports setting */ 2706 if (gateway_ports) 2707 wildcard = 1; 2708 } else if (gateway_ports || is_client) { 2709 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 2710 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 2711 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 2712 (!is_client && gateway_ports == 1)) 2713 wildcard = 1; 2714 else if (strcmp(listen_addr, "localhost") != 0) 2715 addr = listen_addr; 2716 } 2717 if (wildcardp != NULL) 2718 *wildcardp = wildcard; 2719 return addr; 2720} 2721 2722static int 2723channel_setup_fwd_listener(int type, const char *listen_addr, 2724 u_short listen_port, int *allocated_listen_port, 2725 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2726{ 2727 Channel *c; 2728 int sock, r, success = 0, wildcard = 0, is_client; 2729 struct addrinfo hints, *ai, *aitop; 2730 const char *host, *addr; 2731 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 2732 in_port_t *lport_p; 2733 2734 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 2735 listen_addr : host_to_connect; 2736 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 2737 2738 if (host == NULL) { 2739 error("No forward host name."); 2740 return 0; 2741 } 2742 if (strlen(host) >= NI_MAXHOST) { 2743 error("Forward host name too long."); 2744 return 0; 2745 } 2746 2747 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 2748 addr = channel_fwd_bind_addr(listen_addr, &wildcard, 2749 is_client, gateway_ports); 2750 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s", 2751 type, wildcard, (addr == NULL) ? "NULL" : addr); 2752 2753 /* 2754 * getaddrinfo returns a loopback address if the hostname is 2755 * set to NULL and hints.ai_flags is not AI_PASSIVE 2756 */ 2757 memset(&hints, 0, sizeof(hints)); 2758 hints.ai_family = IPv4or6; 2759 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 2760 hints.ai_socktype = SOCK_STREAM; 2761 snprintf(strport, sizeof strport, "%d", listen_port); 2762 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 2763 if (addr == NULL) { 2764 /* This really shouldn't happen */ 2765 packet_disconnect("getaddrinfo: fatal error: %s", 2766 ssh_gai_strerror(r)); 2767 } else { 2768 error("channel_setup_fwd_listener: " 2769 "getaddrinfo(%.64s): %s", addr, 2770 ssh_gai_strerror(r)); 2771 } 2772 return 0; 2773 } 2774 if (allocated_listen_port != NULL) 2775 *allocated_listen_port = 0; 2776 for (ai = aitop; ai; ai = ai->ai_next) { 2777 switch (ai->ai_family) { 2778 case AF_INET: 2779 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 2780 sin_port; 2781 break; 2782 case AF_INET6: 2783 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 2784 sin6_port; 2785 break; 2786 default: 2787 continue; 2788 } 2789 /* 2790 * If allocating a port for -R forwards, then use the 2791 * same port for all address families. 2792 */ 2793 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 && 2794 allocated_listen_port != NULL && *allocated_listen_port > 0) 2795 *lport_p = htons(*allocated_listen_port); 2796 2797 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 2798 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 2799 error("channel_setup_fwd_listener: getnameinfo failed"); 2800 continue; 2801 } 2802 /* Create a port to listen for the host. */ 2803 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 2804 if (sock < 0) { 2805 /* this is no error since kernel may not support ipv6 */ 2806 verbose("socket: %.100s", strerror(errno)); 2807 continue; 2808 } 2809 2810 channel_set_reuseaddr(sock); 2811 if (ai->ai_family == AF_INET6) 2812 sock_set_v6only(sock); 2813 2814 debug("Local forwarding listening on %s port %s.", 2815 ntop, strport); 2816 2817 /* Bind the socket to the address. */ 2818 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 2819 /* address can be in use ipv6 address is already bound */ 2820 if (!ai->ai_next) 2821 error("bind: %.100s", strerror(errno)); 2822 else 2823 verbose("bind: %.100s", strerror(errno)); 2824 2825 close(sock); 2826 continue; 2827 } 2828 /* Start listening for connections on the socket. */ 2829 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 2830 error("listen: %.100s", strerror(errno)); 2831 close(sock); 2832 continue; 2833 } 2834 2835 /* 2836 * listen_port == 0 requests a dynamically allocated port - 2837 * record what we got. 2838 */ 2839 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 && 2840 allocated_listen_port != NULL && 2841 *allocated_listen_port == 0) { 2842 *allocated_listen_port = get_sock_port(sock, 1); 2843 debug("Allocated listen port %d", 2844 *allocated_listen_port); 2845 } 2846 2847 /* Allocate a channel number for the socket. */ 2848 c = channel_new("port listener", type, sock, sock, -1, 2849 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 2850 0, "port listener", 1); 2851 c->path = xstrdup(host); 2852 c->host_port = port_to_connect; 2853 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 2854 if (listen_port == 0 && allocated_listen_port != NULL && 2855 !(datafellows & SSH_BUG_DYNAMIC_RPORT)) 2856 c->listening_port = *allocated_listen_port; 2857 else 2858 c->listening_port = listen_port; 2859 success = 1; 2860 } 2861 if (success == 0) 2862 error("channel_setup_fwd_listener: cannot listen to port: %d", 2863 listen_port); 2864 freeaddrinfo(aitop); 2865 return success; 2866} 2867 2868int 2869channel_cancel_rport_listener(const char *host, u_short port) 2870{ 2871 u_int i; 2872 int found = 0; 2873 2874 for (i = 0; i < channels_alloc; i++) { 2875 Channel *c = channels[i]; 2876 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 2877 continue; 2878 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 2879 debug2("%s: close channel %d", __func__, i); 2880 channel_free(c); 2881 found = 1; 2882 } 2883 } 2884 2885 return (found); 2886} 2887 2888int 2889channel_cancel_lport_listener(const char *lhost, u_short lport, 2890 int cport, int gateway_ports) 2891{ 2892 u_int i; 2893 int found = 0; 2894 const char *addr = channel_fwd_bind_addr(lhost, NULL, 1, gateway_ports); 2895 2896 for (i = 0; i < channels_alloc; i++) { 2897 Channel *c = channels[i]; 2898 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 2899 continue; 2900 if (c->listening_port != lport) 2901 continue; 2902 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 2903 /* skip dynamic forwardings */ 2904 if (c->host_port == 0) 2905 continue; 2906 } else { 2907 if (c->host_port != cport) 2908 continue; 2909 } 2910 if ((c->listening_addr == NULL && addr != NULL) || 2911 (c->listening_addr != NULL && addr == NULL)) 2912 continue; 2913 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 2914 debug2("%s: close channel %d", __func__, i); 2915 channel_free(c); 2916 found = 1; 2917 } 2918 } 2919 2920 return (found); 2921} 2922 2923/* protocol local port fwd, used by ssh (and sshd in v1) */ 2924int 2925channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port, 2926 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2927{ 2928 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, 2929 listen_host, listen_port, NULL, host_to_connect, port_to_connect, 2930 gateway_ports); 2931} 2932 2933/* protocol v2 remote port fwd, used by sshd */ 2934int 2935channel_setup_remote_fwd_listener(const char *listen_address, 2936 u_short listen_port, int *allocated_listen_port, int gateway_ports) 2937{ 2938 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, 2939 listen_address, listen_port, allocated_listen_port, 2940 NULL, 0, gateway_ports); 2941} 2942 2943/* 2944 * Translate the requested rfwd listen host to something usable for 2945 * this server. 2946 */ 2947static const char * 2948channel_rfwd_bind_host(const char *listen_host) 2949{ 2950 if (listen_host == NULL) { 2951 if (datafellows & SSH_BUG_RFWD_ADDR) 2952 return "127.0.0.1"; 2953 else 2954 return "localhost"; 2955 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 2956 if (datafellows & SSH_BUG_RFWD_ADDR) 2957 return "0.0.0.0"; 2958 else 2959 return ""; 2960 } else 2961 return listen_host; 2962} 2963 2964/* 2965 * Initiate forwarding of connections to port "port" on remote host through 2966 * the secure channel to host:port from local side. 2967 * Returns handle (index) for updating the dynamic listen port with 2968 * channel_update_permitted_opens(). 2969 */ 2970int 2971channel_request_remote_forwarding(const char *listen_host, u_short listen_port, 2972 const char *host_to_connect, u_short port_to_connect) 2973{ 2974 int type, success = 0, idx = -1; 2975 2976 /* Send the forward request to the remote side. */ 2977 if (compat20) { 2978 packet_start(SSH2_MSG_GLOBAL_REQUEST); 2979 packet_put_cstring("tcpip-forward"); 2980 packet_put_char(1); /* boolean: want reply */ 2981 packet_put_cstring(channel_rfwd_bind_host(listen_host)); 2982 packet_put_int(listen_port); 2983 packet_send(); 2984 packet_write_wait(); 2985 /* Assume that server accepts the request */ 2986 success = 1; 2987 } else { 2988 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); 2989 packet_put_int(listen_port); 2990 packet_put_cstring(host_to_connect); 2991 packet_put_int(port_to_connect); 2992 packet_send(); 2993 packet_write_wait(); 2994 2995 /* Wait for response from the remote side. */ 2996 type = packet_read(); 2997 switch (type) { 2998 case SSH_SMSG_SUCCESS: 2999 success = 1; 3000 break; 3001 case SSH_SMSG_FAILURE: 3002 break; 3003 default: 3004 /* Unknown packet */ 3005 packet_disconnect("Protocol error for port forward request:" 3006 "received packet type %d.", type); 3007 } 3008 } 3009 if (success) { 3010 /* Record that connection to this host/port is permitted. */ 3011 permitted_opens = xrealloc(permitted_opens, 3012 num_permitted_opens + 1, sizeof(*permitted_opens)); 3013 idx = num_permitted_opens++; 3014 permitted_opens[idx].host_to_connect = xstrdup(host_to_connect); 3015 permitted_opens[idx].port_to_connect = port_to_connect; 3016 permitted_opens[idx].listen_port = listen_port; 3017 } 3018 return (idx); 3019} 3020 3021/* 3022 * Request cancellation of remote forwarding of connection host:port from 3023 * local side. 3024 */ 3025int 3026channel_request_rforward_cancel(const char *host, u_short port) 3027{ 3028 int i; 3029 3030 if (!compat20) 3031 return -1; 3032 3033 for (i = 0; i < num_permitted_opens; i++) { 3034 if (permitted_opens[i].host_to_connect != NULL && 3035 permitted_opens[i].listen_port == port) 3036 break; 3037 } 3038 if (i >= num_permitted_opens) { 3039 debug("%s: requested forward not found", __func__); 3040 return -1; 3041 } 3042 packet_start(SSH2_MSG_GLOBAL_REQUEST); 3043 packet_put_cstring("cancel-tcpip-forward"); 3044 packet_put_char(0); 3045 packet_put_cstring(channel_rfwd_bind_host(host)); 3046 packet_put_int(port); 3047 packet_send(); 3048 3049 permitted_opens[i].listen_port = 0; 3050 permitted_opens[i].port_to_connect = 0; 3051 xfree(permitted_opens[i].host_to_connect); 3052 permitted_opens[i].host_to_connect = NULL; 3053 3054 return 0; 3055} 3056 3057/* 3058 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates 3059 * listening for the port, and sends back a success reply (or disconnect 3060 * message if there was an error). 3061 */ 3062int 3063channel_input_port_forward_request(int is_root, int gateway_ports) 3064{ 3065 u_short port, host_port; 3066 int success = 0; 3067 char *hostname; 3068 3069 /* Get arguments from the packet. */ 3070 port = packet_get_int(); 3071 hostname = packet_get_string(NULL); 3072 host_port = packet_get_int(); 3073 3074#ifndef HAVE_CYGWIN 3075 /* 3076 * Check that an unprivileged user is not trying to forward a 3077 * privileged port. 3078 */ 3079 if (port < IPPORT_RESERVED && !is_root) 3080 packet_disconnect( 3081 "Requested forwarding of port %d but user is not root.", 3082 port); 3083 if (host_port == 0) 3084 packet_disconnect("Dynamic forwarding denied."); 3085#endif 3086 3087 /* Initiate forwarding */ 3088 success = channel_setup_local_fwd_listener(NULL, port, hostname, 3089 host_port, gateway_ports); 3090 3091 /* Free the argument string. */ 3092 xfree(hostname); 3093 3094 return (success ? 0 : -1); 3095} 3096 3097/* 3098 * Permits opening to any host/port if permitted_opens[] is empty. This is 3099 * usually called by the server, because the user could connect to any port 3100 * anyway, and the server has no way to know but to trust the client anyway. 3101 */ 3102void 3103channel_permit_all_opens(void) 3104{ 3105 if (num_permitted_opens == 0) 3106 all_opens_permitted = 1; 3107} 3108 3109void 3110channel_add_permitted_opens(char *host, int port) 3111{ 3112 debug("allow port forwarding to host %s port %d", host, port); 3113 3114 permitted_opens = xrealloc(permitted_opens, 3115 num_permitted_opens + 1, sizeof(*permitted_opens)); 3116 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); 3117 permitted_opens[num_permitted_opens].port_to_connect = port; 3118 num_permitted_opens++; 3119 3120 all_opens_permitted = 0; 3121} 3122 3123/* 3124 * Update the listen port for a dynamic remote forward, after 3125 * the actual 'newport' has been allocated. If 'newport' < 0 is 3126 * passed then they entry will be invalidated. 3127 */ 3128void 3129channel_update_permitted_opens(int idx, int newport) 3130{ 3131 if (idx < 0 || idx >= num_permitted_opens) { 3132 debug("channel_update_permitted_opens: index out of range:" 3133 " %d num_permitted_opens %d", idx, num_permitted_opens); 3134 return; 3135 } 3136 debug("%s allowed port %d for forwarding to host %s port %d", 3137 newport > 0 ? "Updating" : "Removing", 3138 newport, 3139 permitted_opens[idx].host_to_connect, 3140 permitted_opens[idx].port_to_connect); 3141 if (newport >= 0) { 3142 permitted_opens[idx].listen_port = 3143 (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 3144 } else { 3145 permitted_opens[idx].listen_port = 0; 3146 permitted_opens[idx].port_to_connect = 0; 3147 xfree(permitted_opens[idx].host_to_connect); 3148 permitted_opens[idx].host_to_connect = NULL; 3149 } 3150} 3151 3152int 3153channel_add_adm_permitted_opens(char *host, int port) 3154{ 3155 debug("config allows port forwarding to host %s port %d", host, port); 3156 3157 permitted_adm_opens = xrealloc(permitted_adm_opens, 3158 num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens)); 3159 permitted_adm_opens[num_adm_permitted_opens].host_to_connect 3160 = xstrdup(host); 3161 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port; 3162 return ++num_adm_permitted_opens; 3163} 3164 3165void 3166channel_disable_adm_local_opens(void) 3167{ 3168 channel_clear_adm_permitted_opens(); 3169 permitted_adm_opens = xmalloc(sizeof(*permitted_adm_opens)); 3170 permitted_adm_opens[num_adm_permitted_opens].host_to_connect = NULL; 3171 num_adm_permitted_opens = 1; 3172} 3173 3174void 3175channel_clear_permitted_opens(void) 3176{ 3177 int i; 3178 3179 for (i = 0; i < num_permitted_opens; i++) 3180 if (permitted_opens[i].host_to_connect != NULL) 3181 xfree(permitted_opens[i].host_to_connect); 3182 if (num_permitted_opens > 0) { 3183 xfree(permitted_opens); 3184 permitted_opens = NULL; 3185 } 3186 num_permitted_opens = 0; 3187} 3188 3189void 3190channel_clear_adm_permitted_opens(void) 3191{ 3192 int i; 3193 3194 for (i = 0; i < num_adm_permitted_opens; i++) 3195 if (permitted_adm_opens[i].host_to_connect != NULL) 3196 xfree(permitted_adm_opens[i].host_to_connect); 3197 if (num_adm_permitted_opens > 0) { 3198 xfree(permitted_adm_opens); 3199 permitted_adm_opens = NULL; 3200 } 3201 num_adm_permitted_opens = 0; 3202} 3203 3204void 3205channel_print_adm_permitted_opens(void) 3206{ 3207 int i; 3208 3209 printf("permitopen"); 3210 if (num_adm_permitted_opens == 0) { 3211 printf(" any\n"); 3212 return; 3213 } 3214 for (i = 0; i < num_adm_permitted_opens; i++) 3215 if (permitted_adm_opens[i].host_to_connect == NULL) 3216 printf(" none"); 3217 else 3218 printf(" %s:%d", permitted_adm_opens[i].host_to_connect, 3219 permitted_adm_opens[i].port_to_connect); 3220 printf("\n"); 3221} 3222 3223/* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 3224int 3225permitopen_port(const char *p) 3226{ 3227 int port; 3228 3229 if (strcmp(p, "*") == 0) 3230 return FWD_PERMIT_ANY_PORT; 3231 if ((port = a2port(p)) > 0) 3232 return port; 3233 return -1; 3234} 3235 3236static int 3237port_match(u_short allowedport, u_short requestedport) 3238{ 3239 if (allowedport == FWD_PERMIT_ANY_PORT || 3240 allowedport == requestedport) 3241 return 1; 3242 return 0; 3243} 3244 3245/* Try to start non-blocking connect to next host in cctx list */ 3246static int 3247connect_next(struct channel_connect *cctx) 3248{ 3249 int sock, saved_errno; 3250 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3251 3252 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 3253 if (cctx->ai->ai_family != AF_INET && 3254 cctx->ai->ai_family != AF_INET6) 3255 continue; 3256 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 3257 ntop, sizeof(ntop), strport, sizeof(strport), 3258 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3259 error("connect_next: getnameinfo failed"); 3260 continue; 3261 } 3262 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 3263 cctx->ai->ai_protocol)) == -1) { 3264 if (cctx->ai->ai_next == NULL) 3265 error("socket: %.100s", strerror(errno)); 3266 else 3267 verbose("socket: %.100s", strerror(errno)); 3268 continue; 3269 } 3270 if (set_nonblock(sock) == -1) 3271 fatal("%s: set_nonblock(%d)", __func__, sock); 3272 if (connect(sock, cctx->ai->ai_addr, 3273 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 3274 debug("connect_next: host %.100s ([%.100s]:%s): " 3275 "%.100s", cctx->host, ntop, strport, 3276 strerror(errno)); 3277 saved_errno = errno; 3278 close(sock); 3279 errno = saved_errno; 3280 continue; /* fail -- try next */ 3281 } 3282 debug("connect_next: host %.100s ([%.100s]:%s) " 3283 "in progress, fd=%d", cctx->host, ntop, strport, sock); 3284 cctx->ai = cctx->ai->ai_next; 3285 set_nodelay(sock); 3286 return sock; 3287 } 3288 return -1; 3289} 3290 3291static void 3292channel_connect_ctx_free(struct channel_connect *cctx) 3293{ 3294 xfree(cctx->host); 3295 if (cctx->aitop) 3296 freeaddrinfo(cctx->aitop); 3297 bzero(cctx, sizeof(*cctx)); 3298 cctx->host = NULL; 3299 cctx->ai = cctx->aitop = NULL; 3300} 3301 3302/* Return CONNECTING channel to remote host, port */ 3303static Channel * 3304connect_to(const char *host, u_short port, char *ctype, char *rname) 3305{ 3306 struct addrinfo hints; 3307 int gaierr; 3308 int sock = -1; 3309 char strport[NI_MAXSERV]; 3310 struct channel_connect cctx; 3311 Channel *c; 3312 3313 memset(&cctx, 0, sizeof(cctx)); 3314 memset(&hints, 0, sizeof(hints)); 3315 hints.ai_family = IPv4or6; 3316 hints.ai_socktype = SOCK_STREAM; 3317 snprintf(strport, sizeof strport, "%d", port); 3318 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) { 3319 error("connect_to %.100s: unknown host (%s)", host, 3320 ssh_gai_strerror(gaierr)); 3321 return NULL; 3322 } 3323 3324 cctx.host = xstrdup(host); 3325 cctx.port = port; 3326 cctx.ai = cctx.aitop; 3327 3328 if ((sock = connect_next(&cctx)) == -1) { 3329 error("connect to %.100s port %d failed: %s", 3330 host, port, strerror(errno)); 3331 channel_connect_ctx_free(&cctx); 3332 return NULL; 3333 } 3334 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 3335 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 3336 c->connect_ctx = cctx; 3337 return c; 3338} 3339 3340Channel * 3341channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname) 3342{ 3343 int i; 3344 3345 for (i = 0; i < num_permitted_opens; i++) { 3346 if (permitted_opens[i].host_to_connect != NULL && 3347 port_match(permitted_opens[i].listen_port, listen_port)) { 3348 return connect_to( 3349 permitted_opens[i].host_to_connect, 3350 permitted_opens[i].port_to_connect, ctype, rname); 3351 } 3352 } 3353 error("WARNING: Server requests forwarding for unknown listen_port %d", 3354 listen_port); 3355 return NULL; 3356} 3357 3358/* Check if connecting to that port is permitted and connect. */ 3359Channel * 3360channel_connect_to(const char *host, u_short port, char *ctype, char *rname) 3361{ 3362 int i, permit, permit_adm = 1; 3363 3364 permit = all_opens_permitted; 3365 if (!permit) { 3366 for (i = 0; i < num_permitted_opens; i++) 3367 if (permitted_opens[i].host_to_connect != NULL && 3368 port_match(permitted_opens[i].port_to_connect, port) && 3369 strcmp(permitted_opens[i].host_to_connect, host) == 0) 3370 permit = 1; 3371 } 3372 3373 if (num_adm_permitted_opens > 0) { 3374 permit_adm = 0; 3375 for (i = 0; i < num_adm_permitted_opens; i++) 3376 if (permitted_adm_opens[i].host_to_connect != NULL && 3377 port_match(permitted_adm_opens[i].port_to_connect, port) && 3378 strcmp(permitted_adm_opens[i].host_to_connect, host) 3379 == 0) 3380 permit_adm = 1; 3381 } 3382 3383 if (!permit || !permit_adm) { 3384 logit("Received request to connect to host %.100s port %d, " 3385 "but the request was denied.", host, port); 3386 return NULL; 3387 } 3388 return connect_to(host, port, ctype, rname); 3389} 3390 3391void 3392channel_send_window_changes(void) 3393{ 3394 u_int i; 3395 struct winsize ws; 3396 3397 for (i = 0; i < channels_alloc; i++) { 3398 if (channels[i] == NULL || !channels[i]->client_tty || 3399 channels[i]->type != SSH_CHANNEL_OPEN) 3400 continue; 3401 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) 3402 continue; 3403 channel_request_start(i, "window-change", 0); 3404 packet_put_int((u_int)ws.ws_col); 3405 packet_put_int((u_int)ws.ws_row); 3406 packet_put_int((u_int)ws.ws_xpixel); 3407 packet_put_int((u_int)ws.ws_ypixel); 3408 packet_send(); 3409 } 3410} 3411 3412/* -- X11 forwarding */ 3413 3414/* 3415 * Creates an internet domain socket for listening for X11 connections. 3416 * Returns 0 and a suitable display number for the DISPLAY variable 3417 * stored in display_numberp , or -1 if an error occurs. 3418 */ 3419int 3420x11_create_display_inet(int x11_display_offset, int x11_use_localhost, 3421 int single_connection, u_int *display_numberp, int **chanids) 3422{ 3423 Channel *nc = NULL; 3424 int display_number, sock; 3425 u_short port; 3426 struct addrinfo hints, *ai, *aitop; 3427 char strport[NI_MAXSERV]; 3428 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 3429 3430 if (chanids == NULL) 3431 return -1; 3432 3433 for (display_number = x11_display_offset; 3434 display_number < MAX_DISPLAYS; 3435 display_number++) { 3436 port = 6000 + display_number; 3437 memset(&hints, 0, sizeof(hints)); 3438 hints.ai_family = IPv4or6; 3439 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 3440 hints.ai_socktype = SOCK_STREAM; 3441 snprintf(strport, sizeof strport, "%d", port); 3442 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { 3443 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 3444 return -1; 3445 } 3446 for (ai = aitop; ai; ai = ai->ai_next) { 3447 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 3448 continue; 3449 sock = socket(ai->ai_family, ai->ai_socktype, 3450 ai->ai_protocol); 3451 if (sock < 0) { 3452 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 3453#ifdef EPFNOSUPPORT 3454 && (errno != EPFNOSUPPORT) 3455#endif 3456 ) { 3457 error("socket: %.100s", strerror(errno)); 3458 freeaddrinfo(aitop); 3459 return -1; 3460 } else { 3461 debug("x11_create_display_inet: Socket family %d not supported", 3462 ai->ai_family); 3463 continue; 3464 } 3465 } 3466 if (ai->ai_family == AF_INET6) 3467 sock_set_v6only(sock); 3468 if (x11_use_localhost) 3469 channel_set_reuseaddr(sock); 3470 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3471 debug2("bind port %d: %.100s", port, strerror(errno)); 3472 close(sock); 3473 3474 for (n = 0; n < num_socks; n++) { 3475 close(socks[n]); 3476 } 3477 num_socks = 0; 3478 break; 3479 } 3480 socks[num_socks++] = sock; 3481 if (num_socks == NUM_SOCKS) 3482 break; 3483 } 3484 freeaddrinfo(aitop); 3485 if (num_socks > 0) 3486 break; 3487 } 3488 if (display_number >= MAX_DISPLAYS) { 3489 error("Failed to allocate internet-domain X11 display socket."); 3490 return -1; 3491 } 3492 /* Start listening for connections on the socket. */ 3493 for (n = 0; n < num_socks; n++) { 3494 sock = socks[n]; 3495 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 3496 error("listen: %.100s", strerror(errno)); 3497 close(sock); 3498 return -1; 3499 } 3500 } 3501 3502 /* Allocate a channel for each socket. */ 3503 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 3504 for (n = 0; n < num_socks; n++) { 3505 sock = socks[n]; 3506 nc = channel_new("x11 listener", 3507 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 3508 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 3509 0, "X11 inet listener", 1); 3510 nc->single_connection = single_connection; 3511 (*chanids)[n] = nc->self; 3512 } 3513 (*chanids)[n] = -1; 3514 3515 /* Return the display number for the DISPLAY environment variable. */ 3516 *display_numberp = display_number; 3517 return (0); 3518} 3519 3520static int 3521connect_local_xsocket_path(const char *pathname) 3522{ 3523 int sock; 3524 struct sockaddr_un addr; 3525 3526 sock = socket(AF_UNIX, SOCK_STREAM, 0); 3527 if (sock < 0) 3528 error("socket: %.100s", strerror(errno)); 3529 memset(&addr, 0, sizeof(addr)); 3530 addr.sun_family = AF_UNIX; 3531 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 3532 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 3533 return sock; 3534 close(sock); 3535 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 3536 return -1; 3537} 3538 3539static int 3540connect_local_xsocket(u_int dnr) 3541{ 3542 char buf[1024]; 3543 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 3544 return connect_local_xsocket_path(buf); 3545} 3546 3547int 3548x11_connect_display(void) 3549{ 3550 u_int display_number; 3551 const char *display; 3552 char buf[1024], *cp; 3553 struct addrinfo hints, *ai, *aitop; 3554 char strport[NI_MAXSERV]; 3555 int gaierr, sock = 0; 3556 3557 /* Try to open a socket for the local X server. */ 3558 display = getenv("DISPLAY"); 3559 if (!display) { 3560 error("DISPLAY not set."); 3561 return -1; 3562 } 3563 /* 3564 * Now we decode the value of the DISPLAY variable and make a 3565 * connection to the real X server. 3566 */ 3567 3568#ifdef __APPLE__ 3569 /* Check if the display is a path to a socket (as set by launchd). */ 3570 { 3571 char path[PATH_MAX]; 3572 struct stat sbuf; 3573 int is_path_to_socket = 0; 3574 3575 strlcpy(path, display, sizeof(path)); 3576 if (0 == stat(path, &sbuf)) { 3577 is_path_to_socket = 1; 3578 } else { 3579 char *dot = strrchr(path, '.'); 3580 if (dot) { 3581 *dot = '\0'; 3582 /* screen = atoi(dot + 1); */ 3583 if (0 == stat(path, &sbuf)) { 3584 is_path_to_socket=1; 3585 } 3586 } 3587 } 3588 3589 if (is_path_to_socket) { 3590 sock = connect_local_xsocket_path(path); 3591 if (sock < 0) 3592 return -1; 3593 3594 /* OK, we now have a connection to the display. */ 3595 return sock; 3596 } 3597 } 3598#endif 3599 /* 3600 * Check if it is a unix domain socket. Unix domain displays are in 3601 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 3602 */ 3603 if (strncmp(display, "unix:", 5) == 0 || 3604 display[0] == ':') { 3605 /* Connect to the unix domain socket. */ 3606 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) { 3607 error("Could not parse display number from DISPLAY: %.100s", 3608 display); 3609 return -1; 3610 } 3611 /* Create a socket. */ 3612 sock = connect_local_xsocket(display_number); 3613 if (sock < 0) 3614 return -1; 3615 3616 /* OK, we now have a connection to the display. */ 3617 return sock; 3618 } 3619 /* 3620 * Connect to an inet socket. The DISPLAY value is supposedly 3621 * hostname:d[.s], where hostname may also be numeric IP address. 3622 */ 3623 strlcpy(buf, display, sizeof(buf)); 3624 cp = strchr(buf, ':'); 3625 if (!cp) { 3626 error("Could not find ':' in DISPLAY: %.100s", display); 3627 return -1; 3628 } 3629 *cp = 0; 3630 /* buf now contains the host name. But first we parse the display number. */ 3631 if (sscanf(cp + 1, "%u", &display_number) != 1) { 3632 error("Could not parse display number from DISPLAY: %.100s", 3633 display); 3634 return -1; 3635 } 3636 3637 /* Look up the host address */ 3638 memset(&hints, 0, sizeof(hints)); 3639 hints.ai_family = IPv4or6; 3640 hints.ai_socktype = SOCK_STREAM; 3641 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 3642 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 3643 error("%.100s: unknown host. (%s)", buf, 3644 ssh_gai_strerror(gaierr)); 3645 return -1; 3646 } 3647 for (ai = aitop; ai; ai = ai->ai_next) { 3648 /* Create a socket. */ 3649 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3650 if (sock < 0) { 3651 debug2("socket: %.100s", strerror(errno)); 3652 continue; 3653 } 3654 /* Connect it to the display. */ 3655 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3656 debug2("connect %.100s port %u: %.100s", buf, 3657 6000 + display_number, strerror(errno)); 3658 close(sock); 3659 continue; 3660 } 3661 /* Success */ 3662 break; 3663 } 3664 freeaddrinfo(aitop); 3665 if (!ai) { 3666 error("connect %.100s port %u: %.100s", buf, 6000 + display_number, 3667 strerror(errno)); 3668 return -1; 3669 } 3670 set_nodelay(sock); 3671 return sock; 3672} 3673 3674/* 3675 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains 3676 * the remote channel number. We should do whatever we want, and respond 3677 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. 3678 */ 3679 3680/* ARGSUSED */ 3681void 3682x11_input_open(int type, u_int32_t seq, void *ctxt) 3683{ 3684 Channel *c = NULL; 3685 int remote_id, sock = 0; 3686 char *remote_host; 3687 3688 debug("Received X11 open request."); 3689 3690 remote_id = packet_get_int(); 3691 3692 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 3693 remote_host = packet_get_string(NULL); 3694 } else { 3695 remote_host = xstrdup("unknown (remote did not supply name)"); 3696 } 3697 packet_check_eom(); 3698 3699 /* Obtain a connection to the real X display. */ 3700 sock = x11_connect_display(); 3701 if (sock != -1) { 3702 /* Allocate a channel for this connection. */ 3703 c = channel_new("connected x11 socket", 3704 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, 3705 remote_host, 1); 3706 c->remote_id = remote_id; 3707 c->force_drain = 1; 3708 } 3709 xfree(remote_host); 3710 if (c == NULL) { 3711 /* Send refusal to the remote host. */ 3712 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3713 packet_put_int(remote_id); 3714 } else { 3715 /* Send a confirmation to the remote host. */ 3716 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 3717 packet_put_int(remote_id); 3718 packet_put_int(c->self); 3719 } 3720 packet_send(); 3721} 3722 3723/* dummy protocol handler that denies SSH-1 requests (agent/x11) */ 3724/* ARGSUSED */ 3725void 3726deny_input_open(int type, u_int32_t seq, void *ctxt) 3727{ 3728 int rchan = packet_get_int(); 3729 3730 switch (type) { 3731 case SSH_SMSG_AGENT_OPEN: 3732 error("Warning: ssh server tried agent forwarding."); 3733 break; 3734 case SSH_SMSG_X11_OPEN: 3735 error("Warning: ssh server tried X11 forwarding."); 3736 break; 3737 default: 3738 error("deny_input_open: type %d", type); 3739 break; 3740 } 3741 error("Warning: this is probably a break-in attempt by a malicious server."); 3742 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3743 packet_put_int(rchan); 3744 packet_send(); 3745} 3746 3747/* 3748 * Requests forwarding of X11 connections, generates fake authentication 3749 * data, and enables authentication spoofing. 3750 * This should be called in the client only. 3751 */ 3752void 3753x11_request_forwarding_with_spoofing(int client_session_id, const char *disp, 3754 const char *proto, const char *data, int want_reply) 3755{ 3756 u_int data_len = (u_int) strlen(data) / 2; 3757 u_int i, value; 3758 char *new_data; 3759 int screen_number; 3760 const char *cp; 3761 u_int32_t rnd = 0; 3762 3763 if (x11_saved_display == NULL) 3764 x11_saved_display = xstrdup(disp); 3765 else if (strcmp(disp, x11_saved_display) != 0) { 3766 error("x11_request_forwarding_with_spoofing: different " 3767 "$DISPLAY already forwarded"); 3768 return; 3769 } 3770 3771 cp = strchr(disp, ':'); 3772 if (cp) 3773 cp = strchr(cp, '.'); 3774 if (cp) 3775 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 3776 else 3777 screen_number = 0; 3778 3779 if (x11_saved_proto == NULL) { 3780 /* Save protocol name. */ 3781 x11_saved_proto = xstrdup(proto); 3782 /* 3783 * Extract real authentication data and generate fake data 3784 * of the same length. 3785 */ 3786 x11_saved_data = xmalloc(data_len); 3787 x11_fake_data = xmalloc(data_len); 3788 for (i = 0; i < data_len; i++) { 3789 if (sscanf(data + 2 * i, "%2x", &value) != 1) 3790 fatal("x11_request_forwarding: bad " 3791 "authentication data: %.100s", data); 3792 if (i % 4 == 0) 3793 rnd = arc4random(); 3794 x11_saved_data[i] = value; 3795 x11_fake_data[i] = rnd & 0xff; 3796 rnd >>= 8; 3797 } 3798 x11_saved_data_len = data_len; 3799 x11_fake_data_len = data_len; 3800 } 3801 3802 /* Convert the fake data into hex. */ 3803 new_data = tohex(x11_fake_data, data_len); 3804 3805 /* Send the request packet. */ 3806 if (compat20) { 3807 channel_request_start(client_session_id, "x11-req", want_reply); 3808 packet_put_char(0); /* XXX bool single connection */ 3809 } else { 3810 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); 3811 } 3812 packet_put_cstring(proto); 3813 packet_put_cstring(new_data); 3814 packet_put_int(screen_number); 3815 packet_send(); 3816 packet_write_wait(); 3817 xfree(new_data); 3818} 3819 3820 3821/* -- agent forwarding */ 3822 3823/* Sends a message to the server to request authentication fd forwarding. */ 3824 3825void 3826auth_request_forwarding(void) 3827{ 3828 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); 3829 packet_send(); 3830 packet_write_wait(); 3831} 3832