1 /* $OpenBSD: channels.c,v 1.311 2011/06/22 22:08:42 djm Exp $ */ 2 /* $FreeBSD$ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * This file contains functions for generic socket connection forwarding. 8 * There is also code for initiating connection forwarding for X11 connections, 9 * arbitrary tcp/ip connections, and the authentication agent connection. 10 * 11 * As far as I am concerned, the code I have written for this software 12 * can be used freely for any purpose. Any derived versions of this 13 * software must be clearly marked as such, and if the derived work is 14 * incompatible with the protocol description in the RFC file, it must be 15 * called by a name other than "ssh" or "Secure Shell". 16 * 17 * SSH2 support added by Markus Friedl. 18 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 19 * Copyright (c) 1999 Dug Song. All rights reserved. 20 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 32 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 33 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 34 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 35 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 37 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 38 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 39 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 40 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 41 */ 42 43 #include "includes.h" 44 45 #include <sys/types.h> 46 #include <sys/ioctl.h> 47 #include <sys/un.h> 48 #include <sys/socket.h> 49 #ifdef HAVE_SYS_TIME_H 50 # include <sys/time.h> 51 #endif 52 53 #include <netinet/in.h> 54 #include <arpa/inet.h> 55 56 #include <errno.h> 57 #include <fcntl.h> 58 #include <netdb.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <termios.h> 63 #include <unistd.h> 64 #include <stdarg.h> 65 66 #include "openbsd-compat/sys-queue.h" 67 #include "xmalloc.h" 68 #include "ssh.h" 69 #include "ssh1.h" 70 #include "ssh2.h" 71 #include "packet.h" 72 #include "log.h" 73 #include "misc.h" 74 #include "buffer.h" 75 #include "channels.h" 76 #include "compat.h" 77 #include "canohost.h" 78 #include "key.h" 79 #include "authfd.h" 80 #include "pathnames.h" 81 82 /* -- channel core */ 83 84 /* 85 * Pointer to an array containing all allocated channels. The array is 86 * dynamically extended as needed. 87 */ 88 static Channel **channels = NULL; 89 90 /* 91 * Size of the channel array. All slots of the array must always be 92 * initialized (at least the type field); unused slots set to NULL 93 */ 94 static u_int channels_alloc = 0; 95 96 /* 97 * Maximum file descriptor value used in any of the channels. This is 98 * updated in channel_new. 99 */ 100 static int channel_max_fd = 0; 101 102 103 /* -- tcp forwarding */ 104 105 /* 106 * Data structure for storing which hosts are permitted for forward requests. 107 * The local sides of any remote forwards are stored in this array to prevent 108 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 109 * network (which might be behind a firewall). 110 */ 111 typedef struct { 112 char *host_to_connect; /* Connect to 'host'. */ 113 u_short port_to_connect; /* Connect to 'port'. */ 114 u_short listen_port; /* Remote side should listen port number. */ 115 } ForwardPermission; 116 117 /* List of all permitted host/port pairs to connect by the user. */ 118 static ForwardPermission *permitted_opens = NULL; 119 120 /* List of all permitted host/port pairs to connect by the admin. */ 121 static ForwardPermission *permitted_adm_opens = NULL; 122 123 /* Number of permitted host/port pairs in the array permitted by the user. */ 124 static int num_permitted_opens = 0; 125 126 /* Number of permitted host/port pair in the array permitted by the admin. */ 127 static int num_adm_permitted_opens = 0; 128 129 /* 130 * If this is true, all opens are permitted. This is the case on the server 131 * on which we have to trust the client anyway, and the user could do 132 * anything after logging in anyway. 133 */ 134 static int all_opens_permitted = 0; 135 136 137 /* -- X11 forwarding */ 138 139 /* Maximum number of fake X11 displays to try. */ 140 #define MAX_DISPLAYS 1000 141 142 /* Saved X11 local (client) display. */ 143 static char *x11_saved_display = NULL; 144 145 /* Saved X11 authentication protocol name. */ 146 static char *x11_saved_proto = NULL; 147 148 /* Saved X11 authentication data. This is the real data. */ 149 static char *x11_saved_data = NULL; 150 static u_int x11_saved_data_len = 0; 151 152 /* 153 * Fake X11 authentication data. This is what the server will be sending us; 154 * we should replace any occurrences of this by the real data. 155 */ 156 static u_char *x11_fake_data = NULL; 157 static u_int x11_fake_data_len; 158 159 160 /* -- agent forwarding */ 161 162 #define NUM_SOCKS 10 163 164 /* AF_UNSPEC or AF_INET or AF_INET6 */ 165 static int IPv4or6 = AF_UNSPEC; 166 167 /* helper */ 168 static void port_open_helper(Channel *c, char *rtype); 169 170 /* non-blocking connect helpers */ 171 static int connect_next(struct channel_connect *); 172 static void channel_connect_ctx_free(struct channel_connect *); 173 174 /* -- HPN */ 175 176 static int hpn_disabled = 0; 177 static u_int buffer_size = CHAN_HPN_MIN_WINDOW_DEFAULT; 178 179 /* -- channel core */ 180 181 Channel * 182 channel_by_id(int id) 183 { 184 Channel *c; 185 186 if (id < 0 || (u_int)id >= channels_alloc) { 187 logit("channel_by_id: %d: bad id", id); 188 return NULL; 189 } 190 c = channels[id]; 191 if (c == NULL) { 192 logit("channel_by_id: %d: bad id: channel free", id); 193 return NULL; 194 } 195 return c; 196 } 197 198 /* 199 * Returns the channel if it is allowed to receive protocol messages. 200 * Private channels, like listening sockets, may not receive messages. 201 */ 202 Channel * 203 channel_lookup(int id) 204 { 205 Channel *c; 206 207 if ((c = channel_by_id(id)) == NULL) 208 return (NULL); 209 210 switch (c->type) { 211 case SSH_CHANNEL_X11_OPEN: 212 case SSH_CHANNEL_LARVAL: 213 case SSH_CHANNEL_CONNECTING: 214 case SSH_CHANNEL_DYNAMIC: 215 case SSH_CHANNEL_OPENING: 216 case SSH_CHANNEL_OPEN: 217 case SSH_CHANNEL_INPUT_DRAINING: 218 case SSH_CHANNEL_OUTPUT_DRAINING: 219 return (c); 220 } 221 logit("Non-public channel %d, type %d.", id, c->type); 222 return (NULL); 223 } 224 225 /* 226 * Register filedescriptors for a channel, used when allocating a channel or 227 * when the channel consumer/producer is ready, e.g. shell exec'd 228 */ 229 static void 230 channel_register_fds(Channel *c, int rfd, int wfd, int efd, 231 int extusage, int nonblock, int is_tty) 232 { 233 /* Update the maximum file descriptor value. */ 234 channel_max_fd = MAX(channel_max_fd, rfd); 235 channel_max_fd = MAX(channel_max_fd, wfd); 236 channel_max_fd = MAX(channel_max_fd, efd); 237 238 if (rfd != -1) 239 fcntl(rfd, F_SETFD, FD_CLOEXEC); 240 if (wfd != -1 && wfd != rfd) 241 fcntl(wfd, F_SETFD, FD_CLOEXEC); 242 if (efd != -1 && efd != rfd && efd != wfd) 243 fcntl(efd, F_SETFD, FD_CLOEXEC); 244 245 c->rfd = rfd; 246 c->wfd = wfd; 247 c->sock = (rfd == wfd) ? rfd : -1; 248 c->efd = efd; 249 c->extended_usage = extusage; 250 251 if ((c->isatty = is_tty) != 0) 252 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 253 c->wfd_isatty = is_tty || isatty(c->wfd); 254 255 /* enable nonblocking mode */ 256 if (nonblock) { 257 if (rfd != -1) 258 set_nonblock(rfd); 259 if (wfd != -1) 260 set_nonblock(wfd); 261 if (efd != -1) 262 set_nonblock(efd); 263 } 264 } 265 266 /* 267 * Allocate a new channel object and set its type and socket. This will cause 268 * remote_name to be freed. 269 */ 270 Channel * 271 channel_new(char *ctype, int type, int rfd, int wfd, int efd, 272 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) 273 { 274 int found; 275 u_int i; 276 Channel *c; 277 278 /* Do initial allocation if this is the first call. */ 279 if (channels_alloc == 0) { 280 channels_alloc = 10; 281 channels = xcalloc(channels_alloc, sizeof(Channel *)); 282 for (i = 0; i < channels_alloc; i++) 283 channels[i] = NULL; 284 } 285 /* Try to find a free slot where to put the new channel. */ 286 for (found = -1, i = 0; i < channels_alloc; i++) 287 if (channels[i] == NULL) { 288 /* Found a free slot. */ 289 found = (int)i; 290 break; 291 } 292 if (found < 0) { 293 /* There are no free slots. Take last+1 slot and expand the array. */ 294 found = channels_alloc; 295 if (channels_alloc > 10000) 296 fatal("channel_new: internal error: channels_alloc %d " 297 "too big.", channels_alloc); 298 channels = xrealloc(channels, channels_alloc + 10, 299 sizeof(Channel *)); 300 channels_alloc += 10; 301 debug2("channel: expanding %d", channels_alloc); 302 for (i = found; i < channels_alloc; i++) 303 channels[i] = NULL; 304 } 305 /* Initialize and return new channel. */ 306 c = channels[found] = xcalloc(1, sizeof(Channel)); 307 buffer_init(&c->input); 308 buffer_init(&c->output); 309 buffer_init(&c->extended); 310 c->path = NULL; 311 c->ostate = CHAN_OUTPUT_OPEN; 312 c->istate = CHAN_INPUT_OPEN; 313 c->flags = 0; 314 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0); 315 c->self = found; 316 c->type = type; 317 c->ctype = ctype; 318 c->dynamic_window = 0; 319 c->local_window = window; 320 c->local_window_max = window; 321 c->local_consumed = 0; 322 c->local_maxpacket = maxpack; 323 c->remote_id = -1; 324 c->remote_name = xstrdup(remote_name); 325 c->remote_window = 0; 326 c->remote_maxpacket = 0; 327 c->force_drain = 0; 328 c->single_connection = 0; 329 c->detach_user = NULL; 330 c->detach_close = 0; 331 c->open_confirm = NULL; 332 c->open_confirm_ctx = NULL; 333 c->input_filter = NULL; 334 c->output_filter = NULL; 335 c->filter_ctx = NULL; 336 c->filter_cleanup = NULL; 337 c->ctl_chan = -1; 338 c->mux_rcb = NULL; 339 c->mux_ctx = NULL; 340 c->mux_pause = 0; 341 c->delayed = 1; /* prevent call to channel_post handler */ 342 TAILQ_INIT(&c->status_confirms); 343 debug("channel %d: new [%s]", found, remote_name); 344 return c; 345 } 346 347 static int 348 channel_find_maxfd(void) 349 { 350 u_int i; 351 int max = 0; 352 Channel *c; 353 354 for (i = 0; i < channels_alloc; i++) { 355 c = channels[i]; 356 if (c != NULL) { 357 max = MAX(max, c->rfd); 358 max = MAX(max, c->wfd); 359 max = MAX(max, c->efd); 360 } 361 } 362 return max; 363 } 364 365 int 366 channel_close_fd(int *fdp) 367 { 368 int ret = 0, fd = *fdp; 369 370 if (fd != -1) { 371 ret = close(fd); 372 *fdp = -1; 373 if (fd == channel_max_fd) 374 channel_max_fd = channel_find_maxfd(); 375 } 376 return ret; 377 } 378 379 /* Close all channel fd/socket. */ 380 static void 381 channel_close_fds(Channel *c) 382 { 383 channel_close_fd(&c->sock); 384 channel_close_fd(&c->rfd); 385 channel_close_fd(&c->wfd); 386 channel_close_fd(&c->efd); 387 } 388 389 /* Free the channel and close its fd/socket. */ 390 void 391 channel_free(Channel *c) 392 { 393 char *s; 394 u_int i, n; 395 struct channel_confirm *cc; 396 397 for (n = 0, i = 0; i < channels_alloc; i++) 398 if (channels[i]) 399 n++; 400 debug("channel %d: free: %s, nchannels %u", c->self, 401 c->remote_name ? c->remote_name : "???", n); 402 403 s = channel_open_message(); 404 debug3("channel %d: status: %s", c->self, s); 405 xfree(s); 406 407 if (c->sock != -1) 408 shutdown(c->sock, SHUT_RDWR); 409 channel_close_fds(c); 410 buffer_free(&c->input); 411 buffer_free(&c->output); 412 buffer_free(&c->extended); 413 if (c->remote_name) { 414 xfree(c->remote_name); 415 c->remote_name = NULL; 416 } 417 if (c->path) { 418 xfree(c->path); 419 c->path = NULL; 420 } 421 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 422 if (cc->abandon_cb != NULL) 423 cc->abandon_cb(c, cc->ctx); 424 TAILQ_REMOVE(&c->status_confirms, cc, entry); 425 bzero(cc, sizeof(*cc)); 426 xfree(cc); 427 } 428 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 429 c->filter_cleanup(c->self, c->filter_ctx); 430 channels[c->self] = NULL; 431 xfree(c); 432 } 433 434 void 435 channel_free_all(void) 436 { 437 u_int i; 438 439 for (i = 0; i < channels_alloc; i++) 440 if (channels[i] != NULL) 441 channel_free(channels[i]); 442 } 443 444 /* 445 * Closes the sockets/fds of all channels. This is used to close extra file 446 * descriptors after a fork. 447 */ 448 void 449 channel_close_all(void) 450 { 451 u_int i; 452 453 for (i = 0; i < channels_alloc; i++) 454 if (channels[i] != NULL) 455 channel_close_fds(channels[i]); 456 } 457 458 /* 459 * Stop listening to channels. 460 */ 461 void 462 channel_stop_listening(void) 463 { 464 u_int i; 465 Channel *c; 466 467 for (i = 0; i < channels_alloc; i++) { 468 c = channels[i]; 469 if (c != NULL) { 470 switch (c->type) { 471 case SSH_CHANNEL_AUTH_SOCKET: 472 case SSH_CHANNEL_PORT_LISTENER: 473 case SSH_CHANNEL_RPORT_LISTENER: 474 case SSH_CHANNEL_X11_LISTENER: 475 channel_close_fd(&c->sock); 476 channel_free(c); 477 break; 478 } 479 } 480 } 481 } 482 483 /* 484 * Returns true if no channel has too much buffered data, and false if one or 485 * more channel is overfull. 486 */ 487 int 488 channel_not_very_much_buffered_data(void) 489 { 490 u_int i; 491 Channel *c; 492 493 for (i = 0; i < channels_alloc; i++) { 494 c = channels[i]; 495 if (c != NULL && c->type == SSH_CHANNEL_OPEN) { 496 #if 0 497 if (!compat20 && 498 buffer_len(&c->input) > packet_get_maxsize()) { 499 debug2("channel %d: big input buffer %d", 500 c->self, buffer_len(&c->input)); 501 return 0; 502 } 503 #endif 504 if (buffer_len(&c->output) > packet_get_maxsize()) { 505 debug2("channel %d: big output buffer %u > %u", 506 c->self, buffer_len(&c->output), 507 packet_get_maxsize()); 508 return 0; 509 } 510 } 511 } 512 return 1; 513 } 514 515 /* Returns true if any channel is still open. */ 516 int 517 channel_still_open(void) 518 { 519 u_int i; 520 Channel *c; 521 522 for (i = 0; i < channels_alloc; i++) { 523 c = channels[i]; 524 if (c == NULL) 525 continue; 526 switch (c->type) { 527 case SSH_CHANNEL_X11_LISTENER: 528 case SSH_CHANNEL_PORT_LISTENER: 529 case SSH_CHANNEL_RPORT_LISTENER: 530 case SSH_CHANNEL_MUX_LISTENER: 531 case SSH_CHANNEL_CLOSED: 532 case SSH_CHANNEL_AUTH_SOCKET: 533 case SSH_CHANNEL_DYNAMIC: 534 case SSH_CHANNEL_CONNECTING: 535 case SSH_CHANNEL_ZOMBIE: 536 continue; 537 case SSH_CHANNEL_LARVAL: 538 if (!compat20) 539 fatal("cannot happen: SSH_CHANNEL_LARVAL"); 540 continue; 541 case SSH_CHANNEL_OPENING: 542 case SSH_CHANNEL_OPEN: 543 case SSH_CHANNEL_X11_OPEN: 544 case SSH_CHANNEL_MUX_CLIENT: 545 return 1; 546 case SSH_CHANNEL_INPUT_DRAINING: 547 case SSH_CHANNEL_OUTPUT_DRAINING: 548 if (!compat13) 549 fatal("cannot happen: OUT_DRAIN"); 550 return 1; 551 default: 552 fatal("channel_still_open: bad channel type %d", c->type); 553 /* NOTREACHED */ 554 } 555 } 556 return 0; 557 } 558 559 /* Returns the id of an open channel suitable for keepaliving */ 560 int 561 channel_find_open(void) 562 { 563 u_int i; 564 Channel *c; 565 566 for (i = 0; i < channels_alloc; i++) { 567 c = channels[i]; 568 if (c == NULL || c->remote_id < 0) 569 continue; 570 switch (c->type) { 571 case SSH_CHANNEL_CLOSED: 572 case SSH_CHANNEL_DYNAMIC: 573 case SSH_CHANNEL_X11_LISTENER: 574 case SSH_CHANNEL_PORT_LISTENER: 575 case SSH_CHANNEL_RPORT_LISTENER: 576 case SSH_CHANNEL_MUX_LISTENER: 577 case SSH_CHANNEL_MUX_CLIENT: 578 case SSH_CHANNEL_OPENING: 579 case SSH_CHANNEL_CONNECTING: 580 case SSH_CHANNEL_ZOMBIE: 581 continue; 582 case SSH_CHANNEL_LARVAL: 583 case SSH_CHANNEL_AUTH_SOCKET: 584 case SSH_CHANNEL_OPEN: 585 case SSH_CHANNEL_X11_OPEN: 586 return i; 587 case SSH_CHANNEL_INPUT_DRAINING: 588 case SSH_CHANNEL_OUTPUT_DRAINING: 589 if (!compat13) 590 fatal("cannot happen: OUT_DRAIN"); 591 return i; 592 default: 593 fatal("channel_find_open: bad channel type %d", c->type); 594 /* NOTREACHED */ 595 } 596 } 597 return -1; 598 } 599 600 601 /* 602 * Returns a message describing the currently open forwarded connections, 603 * suitable for sending to the client. The message contains crlf pairs for 604 * newlines. 605 */ 606 char * 607 channel_open_message(void) 608 { 609 Buffer buffer; 610 Channel *c; 611 char buf[1024], *cp; 612 u_int i; 613 614 buffer_init(&buffer); 615 snprintf(buf, sizeof buf, "The following connections are open:\r\n"); 616 buffer_append(&buffer, buf, strlen(buf)); 617 for (i = 0; i < channels_alloc; i++) { 618 c = channels[i]; 619 if (c == NULL) 620 continue; 621 switch (c->type) { 622 case SSH_CHANNEL_X11_LISTENER: 623 case SSH_CHANNEL_PORT_LISTENER: 624 case SSH_CHANNEL_RPORT_LISTENER: 625 case SSH_CHANNEL_CLOSED: 626 case SSH_CHANNEL_AUTH_SOCKET: 627 case SSH_CHANNEL_ZOMBIE: 628 case SSH_CHANNEL_MUX_CLIENT: 629 case SSH_CHANNEL_MUX_LISTENER: 630 continue; 631 case SSH_CHANNEL_LARVAL: 632 case SSH_CHANNEL_OPENING: 633 case SSH_CHANNEL_CONNECTING: 634 case SSH_CHANNEL_DYNAMIC: 635 case SSH_CHANNEL_OPEN: 636 case SSH_CHANNEL_X11_OPEN: 637 case SSH_CHANNEL_INPUT_DRAINING: 638 case SSH_CHANNEL_OUTPUT_DRAINING: 639 snprintf(buf, sizeof buf, 640 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n", 641 c->self, c->remote_name, 642 c->type, c->remote_id, 643 c->istate, buffer_len(&c->input), 644 c->ostate, buffer_len(&c->output), 645 c->rfd, c->wfd, c->ctl_chan); 646 buffer_append(&buffer, buf, strlen(buf)); 647 continue; 648 default: 649 fatal("channel_open_message: bad channel type %d", c->type); 650 /* NOTREACHED */ 651 } 652 } 653 buffer_append(&buffer, "\0", 1); 654 cp = xstrdup(buffer_ptr(&buffer)); 655 buffer_free(&buffer); 656 return cp; 657 } 658 659 void 660 channel_send_open(int id) 661 { 662 Channel *c = channel_lookup(id); 663 664 if (c == NULL) { 665 logit("channel_send_open: %d: bad id", id); 666 return; 667 } 668 debug2("channel %d: send open", id); 669 packet_start(SSH2_MSG_CHANNEL_OPEN); 670 packet_put_cstring(c->ctype); 671 packet_put_int(c->self); 672 packet_put_int(c->local_window); 673 packet_put_int(c->local_maxpacket); 674 packet_send(); 675 } 676 677 void 678 channel_request_start(int id, char *service, int wantconfirm) 679 { 680 Channel *c = channel_lookup(id); 681 682 if (c == NULL) { 683 logit("channel_request_start: %d: unknown channel id", id); 684 return; 685 } 686 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 687 packet_start(SSH2_MSG_CHANNEL_REQUEST); 688 packet_put_int(c->remote_id); 689 packet_put_cstring(service); 690 packet_put_char(wantconfirm); 691 } 692 693 void 694 channel_register_status_confirm(int id, channel_confirm_cb *cb, 695 channel_confirm_abandon_cb *abandon_cb, void *ctx) 696 { 697 struct channel_confirm *cc; 698 Channel *c; 699 700 if ((c = channel_lookup(id)) == NULL) 701 fatal("channel_register_expect: %d: bad id", id); 702 703 cc = xmalloc(sizeof(*cc)); 704 cc->cb = cb; 705 cc->abandon_cb = abandon_cb; 706 cc->ctx = ctx; 707 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 708 } 709 710 void 711 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx) 712 { 713 Channel *c = channel_lookup(id); 714 715 if (c == NULL) { 716 logit("channel_register_open_confirm: %d: bad id", id); 717 return; 718 } 719 c->open_confirm = fn; 720 c->open_confirm_ctx = ctx; 721 } 722 723 void 724 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close) 725 { 726 Channel *c = channel_by_id(id); 727 728 if (c == NULL) { 729 logit("channel_register_cleanup: %d: bad id", id); 730 return; 731 } 732 c->detach_user = fn; 733 c->detach_close = do_close; 734 } 735 736 void 737 channel_cancel_cleanup(int id) 738 { 739 Channel *c = channel_by_id(id); 740 741 if (c == NULL) { 742 logit("channel_cancel_cleanup: %d: bad id", id); 743 return; 744 } 745 c->detach_user = NULL; 746 c->detach_close = 0; 747 } 748 749 void 750 channel_register_filter(int id, channel_infilter_fn *ifn, 751 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 752 { 753 Channel *c = channel_lookup(id); 754 755 if (c == NULL) { 756 logit("channel_register_filter: %d: bad id", id); 757 return; 758 } 759 c->input_filter = ifn; 760 c->output_filter = ofn; 761 c->filter_ctx = ctx; 762 c->filter_cleanup = cfn; 763 } 764 765 void 766 channel_set_fds(int id, int rfd, int wfd, int efd, 767 int extusage, int nonblock, int is_tty, u_int window_max) 768 { 769 Channel *c = channel_lookup(id); 770 771 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 772 fatal("channel_activate for non-larval channel %d.", id); 773 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty); 774 c->type = SSH_CHANNEL_OPEN; 775 c->local_window = c->local_window_max = window_max; 776 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 777 packet_put_int(c->remote_id); 778 packet_put_int(c->local_window); 779 packet_send(); 780 } 781 782 /* 783 * 'channel_pre*' are called just before select() to add any bits relevant to 784 * channels in the select bitmasks. 785 */ 786 /* 787 * 'channel_post*': perform any appropriate operations for channels which 788 * have events pending. 789 */ 790 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset); 791 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; 792 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; 793 794 /* ARGSUSED */ 795 static void 796 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset) 797 { 798 FD_SET(c->sock, readset); 799 } 800 801 /* ARGSUSED */ 802 static void 803 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset) 804 { 805 debug3("channel %d: waiting for connection", c->self); 806 FD_SET(c->sock, writeset); 807 } 808 809 static void 810 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset) 811 { 812 if (buffer_len(&c->input) < packet_get_maxsize()) 813 FD_SET(c->sock, readset); 814 if (buffer_len(&c->output) > 0) 815 FD_SET(c->sock, writeset); 816 } 817 818 static u_int 819 channel_tcpwinsz(void) 820 { 821 u_int32_t tcpwinsz; 822 socklen_t optsz; 823 int ret, sd; 824 u_int maxlen; 825 826 /* If we are not on a socket return 128KB. */ 827 if (!packet_connection_is_on_socket()) 828 return (128 * 1024); 829 830 tcpwinsz = 0; 831 optsz = sizeof(tcpwinsz); 832 sd = packet_get_connection_in(); 833 ret = getsockopt(sd, SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz); 834 835 /* Return no more than the maximum buffer size. */ 836 maxlen = buffer_get_max_len(); 837 if ((ret == 0) && tcpwinsz > maxlen) 838 tcpwinsz = maxlen; 839 /* In case getsockopt() failed return a minimum. */ 840 if (tcpwinsz == 0) 841 tcpwinsz = CHAN_TCP_WINDOW_DEFAULT; 842 debug2("tcpwinsz: %d for connection: %d", tcpwinsz, sd); 843 return (tcpwinsz); 844 } 845 846 static void 847 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset) 848 { 849 u_int limit; 850 851 /* Check buffer limits. */ 852 if (!c->tcpwinsz || c->dynamic_window > 0) 853 c->tcpwinsz = channel_tcpwinsz(); 854 855 limit = MIN(compat20 ? c->remote_window : packet_get_maxsize(), 856 2 * c->tcpwinsz); 857 858 if (c->istate == CHAN_INPUT_OPEN && 859 limit > 0 && 860 buffer_len(&c->input) < limit && 861 buffer_check_alloc(&c->input, CHAN_RBUF)) 862 FD_SET(c->rfd, readset); 863 if (c->ostate == CHAN_OUTPUT_OPEN || 864 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 865 if (buffer_len(&c->output) > 0) { 866 FD_SET(c->wfd, writeset); 867 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 868 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 869 debug2("channel %d: obuf_empty delayed efd %d/(%d)", 870 c->self, c->efd, buffer_len(&c->extended)); 871 else 872 chan_obuf_empty(c); 873 } 874 } 875 /** XXX check close conditions, too */ 876 if (compat20 && c->efd != -1 && 877 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) { 878 if (c->extended_usage == CHAN_EXTENDED_WRITE && 879 buffer_len(&c->extended) > 0) 880 FD_SET(c->efd, writeset); 881 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 882 (c->extended_usage == CHAN_EXTENDED_READ || 883 c->extended_usage == CHAN_EXTENDED_IGNORE) && 884 buffer_len(&c->extended) < c->remote_window) 885 FD_SET(c->efd, readset); 886 } 887 /* XXX: What about efd? races? */ 888 } 889 890 /* ARGSUSED */ 891 static void 892 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset) 893 { 894 if (buffer_len(&c->input) == 0) { 895 packet_start(SSH_MSG_CHANNEL_CLOSE); 896 packet_put_int(c->remote_id); 897 packet_send(); 898 c->type = SSH_CHANNEL_CLOSED; 899 debug2("channel %d: closing after input drain.", c->self); 900 } 901 } 902 903 /* ARGSUSED */ 904 static void 905 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset) 906 { 907 if (buffer_len(&c->output) == 0) 908 chan_mark_dead(c); 909 else 910 FD_SET(c->sock, writeset); 911 } 912 913 /* 914 * This is a special state for X11 authentication spoofing. An opened X11 915 * connection (when authentication spoofing is being done) remains in this 916 * state until the first packet has been completely read. The authentication 917 * data in that packet is then substituted by the real data if it matches the 918 * fake data, and the channel is put into normal mode. 919 * XXX All this happens at the client side. 920 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 921 */ 922 static int 923 x11_open_helper(Buffer *b) 924 { 925 u_char *ucp; 926 u_int proto_len, data_len; 927 928 /* Check if the fixed size part of the packet is in buffer. */ 929 if (buffer_len(b) < 12) 930 return 0; 931 932 /* Parse the lengths of variable-length fields. */ 933 ucp = buffer_ptr(b); 934 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 935 proto_len = 256 * ucp[6] + ucp[7]; 936 data_len = 256 * ucp[8] + ucp[9]; 937 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 938 proto_len = ucp[6] + 256 * ucp[7]; 939 data_len = ucp[8] + 256 * ucp[9]; 940 } else { 941 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 942 ucp[0]); 943 return -1; 944 } 945 946 /* Check if the whole packet is in buffer. */ 947 if (buffer_len(b) < 948 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 949 return 0; 950 951 /* Check if authentication protocol matches. */ 952 if (proto_len != strlen(x11_saved_proto) || 953 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { 954 debug2("X11 connection uses different authentication protocol."); 955 return -1; 956 } 957 /* Check if authentication data matches our fake data. */ 958 if (data_len != x11_fake_data_len || 959 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 960 x11_fake_data, x11_fake_data_len) != 0) { 961 debug2("X11 auth data does not match fake data."); 962 return -1; 963 } 964 /* Check fake data length */ 965 if (x11_fake_data_len != x11_saved_data_len) { 966 error("X11 fake_data_len %d != saved_data_len %d", 967 x11_fake_data_len, x11_saved_data_len); 968 return -1; 969 } 970 /* 971 * Received authentication protocol and data match 972 * our fake data. Substitute the fake data with real 973 * data. 974 */ 975 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 976 x11_saved_data, x11_saved_data_len); 977 return 1; 978 } 979 980 static void 981 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset) 982 { 983 int ret = x11_open_helper(&c->output); 984 985 if (ret == 1) { 986 /* Start normal processing for the channel. */ 987 c->type = SSH_CHANNEL_OPEN; 988 channel_pre_open_13(c, readset, writeset); 989 } else if (ret == -1) { 990 /* 991 * We have received an X11 connection that has bad 992 * authentication information. 993 */ 994 logit("X11 connection rejected because of wrong authentication."); 995 buffer_clear(&c->input); 996 buffer_clear(&c->output); 997 channel_close_fd(&c->sock); 998 c->sock = -1; 999 c->type = SSH_CHANNEL_CLOSED; 1000 packet_start(SSH_MSG_CHANNEL_CLOSE); 1001 packet_put_int(c->remote_id); 1002 packet_send(); 1003 } 1004 } 1005 1006 static void 1007 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset) 1008 { 1009 int ret = x11_open_helper(&c->output); 1010 1011 /* c->force_drain = 1; */ 1012 1013 if (ret == 1) { 1014 c->type = SSH_CHANNEL_OPEN; 1015 channel_pre_open(c, readset, writeset); 1016 } else if (ret == -1) { 1017 logit("X11 connection rejected because of wrong authentication."); 1018 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); 1019 chan_read_failed(c); 1020 buffer_clear(&c->input); 1021 chan_ibuf_empty(c); 1022 buffer_clear(&c->output); 1023 /* for proto v1, the peer will send an IEOF */ 1024 if (compat20) 1025 chan_write_failed(c); 1026 else 1027 c->type = SSH_CHANNEL_OPEN; 1028 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1029 } 1030 } 1031 1032 static void 1033 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1034 { 1035 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1036 buffer_check_alloc(&c->input, CHAN_RBUF)) 1037 FD_SET(c->rfd, readset); 1038 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1039 /* clear buffer immediately (discard any partial packet) */ 1040 buffer_clear(&c->input); 1041 chan_ibuf_empty(c); 1042 /* Start output drain. XXX just kill chan? */ 1043 chan_rcvd_oclose(c); 1044 } 1045 if (c->ostate == CHAN_OUTPUT_OPEN || 1046 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1047 if (buffer_len(&c->output) > 0) 1048 FD_SET(c->wfd, writeset); 1049 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1050 chan_obuf_empty(c); 1051 } 1052 } 1053 1054 /* try to decode a socks4 header */ 1055 /* ARGSUSED */ 1056 static int 1057 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset) 1058 { 1059 char *p, *host; 1060 u_int len, have, i, found, need; 1061 char username[256]; 1062 struct { 1063 u_int8_t version; 1064 u_int8_t command; 1065 u_int16_t dest_port; 1066 struct in_addr dest_addr; 1067 } s4_req, s4_rsp; 1068 1069 debug2("channel %d: decode socks4", c->self); 1070 1071 have = buffer_len(&c->input); 1072 len = sizeof(s4_req); 1073 if (have < len) 1074 return 0; 1075 p = buffer_ptr(&c->input); 1076 1077 need = 1; 1078 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1079 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1080 debug2("channel %d: socks4a request", c->self); 1081 /* ... and needs an extra string (the hostname) */ 1082 need = 2; 1083 } 1084 /* Check for terminating NUL on the string(s) */ 1085 for (found = 0, i = len; i < have; i++) { 1086 if (p[i] == '\0') { 1087 found++; 1088 if (found == need) 1089 break; 1090 } 1091 if (i > 1024) { 1092 /* the peer is probably sending garbage */ 1093 debug("channel %d: decode socks4: too long", 1094 c->self); 1095 return -1; 1096 } 1097 } 1098 if (found < need) 1099 return 0; 1100 buffer_get(&c->input, (char *)&s4_req.version, 1); 1101 buffer_get(&c->input, (char *)&s4_req.command, 1); 1102 buffer_get(&c->input, (char *)&s4_req.dest_port, 2); 1103 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); 1104 have = buffer_len(&c->input); 1105 p = buffer_ptr(&c->input); 1106 len = strlen(p); 1107 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1108 len++; /* trailing '\0' */ 1109 if (len > have) 1110 fatal("channel %d: decode socks4: len %d > have %d", 1111 c->self, len, have); 1112 strlcpy(username, p, sizeof(username)); 1113 buffer_consume(&c->input, len); 1114 1115 if (c->path != NULL) { 1116 xfree(c->path); 1117 c->path = NULL; 1118 } 1119 if (need == 1) { /* SOCKS4: one string */ 1120 host = inet_ntoa(s4_req.dest_addr); 1121 c->path = xstrdup(host); 1122 } else { /* SOCKS4A: two strings */ 1123 have = buffer_len(&c->input); 1124 p = buffer_ptr(&c->input); 1125 len = strlen(p); 1126 debug2("channel %d: decode socks4a: host %s/%d", 1127 c->self, p, len); 1128 len++; /* trailing '\0' */ 1129 if (len > have) 1130 fatal("channel %d: decode socks4a: len %d > have %d", 1131 c->self, len, have); 1132 if (len > NI_MAXHOST) { 1133 error("channel %d: hostname \"%.100s\" too long", 1134 c->self, p); 1135 return -1; 1136 } 1137 c->path = xstrdup(p); 1138 buffer_consume(&c->input, len); 1139 } 1140 c->host_port = ntohs(s4_req.dest_port); 1141 1142 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1143 c->self, c->path, c->host_port, s4_req.command); 1144 1145 if (s4_req.command != 1) { 1146 debug("channel %d: cannot handle: %s cn %d", 1147 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1148 return -1; 1149 } 1150 s4_rsp.version = 0; /* vn: 0 for reply */ 1151 s4_rsp.command = 90; /* cd: req granted */ 1152 s4_rsp.dest_port = 0; /* ignored */ 1153 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1154 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp)); 1155 return 1; 1156 } 1157 1158 /* try to decode a socks5 header */ 1159 #define SSH_SOCKS5_AUTHDONE 0x1000 1160 #define SSH_SOCKS5_NOAUTH 0x00 1161 #define SSH_SOCKS5_IPV4 0x01 1162 #define SSH_SOCKS5_DOMAIN 0x03 1163 #define SSH_SOCKS5_IPV6 0x04 1164 #define SSH_SOCKS5_CONNECT 0x01 1165 #define SSH_SOCKS5_SUCCESS 0x00 1166 1167 /* ARGSUSED */ 1168 static int 1169 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset) 1170 { 1171 struct { 1172 u_int8_t version; 1173 u_int8_t command; 1174 u_int8_t reserved; 1175 u_int8_t atyp; 1176 } s5_req, s5_rsp; 1177 u_int16_t dest_port; 1178 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1179 u_int have, need, i, found, nmethods, addrlen, af; 1180 1181 debug2("channel %d: decode socks5", c->self); 1182 p = buffer_ptr(&c->input); 1183 if (p[0] != 0x05) 1184 return -1; 1185 have = buffer_len(&c->input); 1186 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1187 /* format: ver | nmethods | methods */ 1188 if (have < 2) 1189 return 0; 1190 nmethods = p[1]; 1191 if (have < nmethods + 2) 1192 return 0; 1193 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1194 for (found = 0, i = 2; i < nmethods + 2; i++) { 1195 if (p[i] == SSH_SOCKS5_NOAUTH) { 1196 found = 1; 1197 break; 1198 } 1199 } 1200 if (!found) { 1201 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1202 c->self); 1203 return -1; 1204 } 1205 buffer_consume(&c->input, nmethods + 2); 1206 buffer_put_char(&c->output, 0x05); /* version */ 1207 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ 1208 FD_SET(c->sock, writeset); 1209 c->flags |= SSH_SOCKS5_AUTHDONE; 1210 debug2("channel %d: socks5 auth done", c->self); 1211 return 0; /* need more */ 1212 } 1213 debug2("channel %d: socks5 post auth", c->self); 1214 if (have < sizeof(s5_req)+1) 1215 return 0; /* need more */ 1216 memcpy(&s5_req, p, sizeof(s5_req)); 1217 if (s5_req.version != 0x05 || 1218 s5_req.command != SSH_SOCKS5_CONNECT || 1219 s5_req.reserved != 0x00) { 1220 debug2("channel %d: only socks5 connect supported", c->self); 1221 return -1; 1222 } 1223 switch (s5_req.atyp){ 1224 case SSH_SOCKS5_IPV4: 1225 addrlen = 4; 1226 af = AF_INET; 1227 break; 1228 case SSH_SOCKS5_DOMAIN: 1229 addrlen = p[sizeof(s5_req)]; 1230 af = -1; 1231 break; 1232 case SSH_SOCKS5_IPV6: 1233 addrlen = 16; 1234 af = AF_INET6; 1235 break; 1236 default: 1237 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1238 return -1; 1239 } 1240 need = sizeof(s5_req) + addrlen + 2; 1241 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1242 need++; 1243 if (have < need) 1244 return 0; 1245 buffer_consume(&c->input, sizeof(s5_req)); 1246 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1247 buffer_consume(&c->input, 1); /* host string length */ 1248 buffer_get(&c->input, (char *)&dest_addr, addrlen); 1249 buffer_get(&c->input, (char *)&dest_port, 2); 1250 dest_addr[addrlen] = '\0'; 1251 if (c->path != NULL) { 1252 xfree(c->path); 1253 c->path = NULL; 1254 } 1255 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1256 if (addrlen >= NI_MAXHOST) { 1257 error("channel %d: dynamic request: socks5 hostname " 1258 "\"%.100s\" too long", c->self, dest_addr); 1259 return -1; 1260 } 1261 c->path = xstrdup(dest_addr); 1262 } else { 1263 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1264 return -1; 1265 c->path = xstrdup(ntop); 1266 } 1267 c->host_port = ntohs(dest_port); 1268 1269 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1270 c->self, c->path, c->host_port, s5_req.command); 1271 1272 s5_rsp.version = 0x05; 1273 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1274 s5_rsp.reserved = 0; /* ignored */ 1275 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1276 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY; 1277 dest_port = 0; /* ignored */ 1278 1279 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp)); 1280 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr)); 1281 buffer_append(&c->output, &dest_port, sizeof(dest_port)); 1282 return 1; 1283 } 1284 1285 Channel * 1286 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect, 1287 int in, int out) 1288 { 1289 Channel *c; 1290 1291 debug("channel_connect_stdio_fwd %s:%d", host_to_connect, 1292 port_to_connect); 1293 1294 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out, 1295 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1296 0, "stdio-forward", /*nonblock*/0); 1297 1298 c->path = xstrdup(host_to_connect); 1299 c->host_port = port_to_connect; 1300 c->listening_port = 0; 1301 c->force_drain = 1; 1302 1303 channel_register_fds(c, in, out, -1, 0, 1, 0); 1304 port_open_helper(c, "direct-tcpip"); 1305 1306 return c; 1307 } 1308 1309 /* dynamic port forwarding */ 1310 static void 1311 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset) 1312 { 1313 u_char *p; 1314 u_int have; 1315 int ret; 1316 1317 have = buffer_len(&c->input); 1318 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1319 /* buffer_dump(&c->input); */ 1320 /* check if the fixed size part of the packet is in buffer. */ 1321 if (have < 3) { 1322 /* need more */ 1323 FD_SET(c->sock, readset); 1324 return; 1325 } 1326 /* try to guess the protocol */ 1327 p = buffer_ptr(&c->input); 1328 switch (p[0]) { 1329 case 0x04: 1330 ret = channel_decode_socks4(c, readset, writeset); 1331 break; 1332 case 0x05: 1333 ret = channel_decode_socks5(c, readset, writeset); 1334 break; 1335 default: 1336 ret = -1; 1337 break; 1338 } 1339 if (ret < 0) { 1340 chan_mark_dead(c); 1341 } else if (ret == 0) { 1342 debug2("channel %d: pre_dynamic: need more", c->self); 1343 /* need more */ 1344 FD_SET(c->sock, readset); 1345 } else { 1346 /* switch to the next state */ 1347 c->type = SSH_CHANNEL_OPENING; 1348 port_open_helper(c, "direct-tcpip"); 1349 } 1350 } 1351 1352 /* This is our fake X11 server socket. */ 1353 /* ARGSUSED */ 1354 static void 1355 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset) 1356 { 1357 Channel *nc; 1358 struct sockaddr_storage addr; 1359 int newsock; 1360 socklen_t addrlen; 1361 char buf[16384], *remote_ipaddr; 1362 int remote_port; 1363 1364 if (FD_ISSET(c->sock, readset)) { 1365 debug("X11 connection requested."); 1366 addrlen = sizeof(addr); 1367 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1368 if (c->single_connection) { 1369 debug2("single_connection: closing X11 listener."); 1370 channel_close_fd(&c->sock); 1371 chan_mark_dead(c); 1372 } 1373 if (newsock < 0) { 1374 error("accept: %.100s", strerror(errno)); 1375 return; 1376 } 1377 set_nodelay(newsock); 1378 remote_ipaddr = get_peer_ipaddr(newsock); 1379 remote_port = get_peer_port(newsock); 1380 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1381 remote_ipaddr, remote_port); 1382 1383 nc = channel_new("accepted x11 socket", 1384 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1385 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1386 if (compat20) { 1387 packet_start(SSH2_MSG_CHANNEL_OPEN); 1388 packet_put_cstring("x11"); 1389 packet_put_int(nc->self); 1390 packet_put_int(nc->local_window_max); 1391 packet_put_int(nc->local_maxpacket); 1392 /* originator ipaddr and port */ 1393 packet_put_cstring(remote_ipaddr); 1394 if (datafellows & SSH_BUG_X11FWD) { 1395 debug2("ssh2 x11 bug compat mode"); 1396 } else { 1397 packet_put_int(remote_port); 1398 } 1399 packet_send(); 1400 } else { 1401 packet_start(SSH_SMSG_X11_OPEN); 1402 packet_put_int(nc->self); 1403 if (packet_get_protocol_flags() & 1404 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1405 packet_put_cstring(buf); 1406 packet_send(); 1407 } 1408 xfree(remote_ipaddr); 1409 } 1410 } 1411 1412 static void 1413 port_open_helper(Channel *c, char *rtype) 1414 { 1415 int direct; 1416 char buf[1024]; 1417 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1418 int remote_port = get_peer_port(c->sock); 1419 1420 if (remote_port == -1) { 1421 /* Fake addr/port to appease peers that validate it (Tectia) */ 1422 xfree(remote_ipaddr); 1423 remote_ipaddr = xstrdup("127.0.0.1"); 1424 remote_port = 65535; 1425 } 1426 1427 direct = (strcmp(rtype, "direct-tcpip") == 0); 1428 1429 snprintf(buf, sizeof buf, 1430 "%s: listening port %d for %.100s port %d, " 1431 "connect from %.200s port %d", 1432 rtype, c->listening_port, c->path, c->host_port, 1433 remote_ipaddr, remote_port); 1434 1435 xfree(c->remote_name); 1436 c->remote_name = xstrdup(buf); 1437 1438 if (compat20) { 1439 packet_start(SSH2_MSG_CHANNEL_OPEN); 1440 packet_put_cstring(rtype); 1441 packet_put_int(c->self); 1442 packet_put_int(c->local_window_max); 1443 packet_put_int(c->local_maxpacket); 1444 if (direct) { 1445 /* target host, port */ 1446 packet_put_cstring(c->path); 1447 packet_put_int(c->host_port); 1448 } else { 1449 /* listen address, port */ 1450 packet_put_cstring(c->path); 1451 packet_put_int(c->listening_port); 1452 } 1453 /* originator host and port */ 1454 packet_put_cstring(remote_ipaddr); 1455 packet_put_int((u_int)remote_port); 1456 packet_send(); 1457 } else { 1458 packet_start(SSH_MSG_PORT_OPEN); 1459 packet_put_int(c->self); 1460 packet_put_cstring(c->path); 1461 packet_put_int(c->host_port); 1462 if (packet_get_protocol_flags() & 1463 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1464 packet_put_cstring(c->remote_name); 1465 packet_send(); 1466 } 1467 xfree(remote_ipaddr); 1468 } 1469 1470 static void 1471 channel_set_reuseaddr(int fd) 1472 { 1473 int on = 1; 1474 1475 /* 1476 * Set socket options. 1477 * Allow local port reuse in TIME_WAIT. 1478 */ 1479 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) 1480 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); 1481 } 1482 1483 /* 1484 * This socket is listening for connections to a forwarded TCP/IP port. 1485 */ 1486 /* ARGSUSED */ 1487 static void 1488 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset) 1489 { 1490 Channel *nc; 1491 struct sockaddr_storage addr; 1492 int newsock, nextstate; 1493 socklen_t addrlen; 1494 char *rtype; 1495 1496 if (FD_ISSET(c->sock, readset)) { 1497 debug("Connection to port %d forwarding " 1498 "to %.100s port %d requested.", 1499 c->listening_port, c->path, c->host_port); 1500 1501 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1502 nextstate = SSH_CHANNEL_OPENING; 1503 rtype = "forwarded-tcpip"; 1504 } else { 1505 if (c->host_port == 0) { 1506 nextstate = SSH_CHANNEL_DYNAMIC; 1507 rtype = "dynamic-tcpip"; 1508 } else { 1509 nextstate = SSH_CHANNEL_OPENING; 1510 rtype = "direct-tcpip"; 1511 } 1512 } 1513 1514 addrlen = sizeof(addr); 1515 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1516 if (newsock < 0) { 1517 error("accept: %.100s", strerror(errno)); 1518 return; 1519 } 1520 set_nodelay(newsock); 1521 nc = channel_new(rtype, nextstate, newsock, newsock, -1, 1522 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1523 nc->listening_port = c->listening_port; 1524 nc->host_port = c->host_port; 1525 if (c->path != NULL) 1526 nc->path = xstrdup(c->path); 1527 1528 if (nextstate != SSH_CHANNEL_DYNAMIC) 1529 port_open_helper(nc, rtype); 1530 } 1531 } 1532 1533 /* 1534 * This is the authentication agent socket listening for connections from 1535 * clients. 1536 */ 1537 /* ARGSUSED */ 1538 static void 1539 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset) 1540 { 1541 Channel *nc; 1542 int newsock; 1543 struct sockaddr_storage addr; 1544 socklen_t addrlen; 1545 1546 if (FD_ISSET(c->sock, readset)) { 1547 addrlen = sizeof(addr); 1548 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1549 if (newsock < 0) { 1550 error("accept from auth socket: %.100s", strerror(errno)); 1551 return; 1552 } 1553 nc = channel_new("accepted auth socket", 1554 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1555 c->local_window_max, c->local_maxpacket, 1556 0, "accepted auth socket", 1); 1557 if (compat20) { 1558 packet_start(SSH2_MSG_CHANNEL_OPEN); 1559 packet_put_cstring("auth-agent@openssh.com"); 1560 packet_put_int(nc->self); 1561 packet_put_int(c->local_window_max); 1562 packet_put_int(c->local_maxpacket); 1563 } else { 1564 packet_start(SSH_SMSG_AGENT_OPEN); 1565 packet_put_int(nc->self); 1566 } 1567 packet_send(); 1568 } 1569 } 1570 1571 /* ARGSUSED */ 1572 static void 1573 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset) 1574 { 1575 int err = 0, sock; 1576 socklen_t sz = sizeof(err); 1577 1578 if (FD_ISSET(c->sock, writeset)) { 1579 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { 1580 err = errno; 1581 error("getsockopt SO_ERROR failed"); 1582 } 1583 if (err == 0) { 1584 debug("channel %d: connected to %s port %d", 1585 c->self, c->connect_ctx.host, c->connect_ctx.port); 1586 channel_connect_ctx_free(&c->connect_ctx); 1587 c->type = SSH_CHANNEL_OPEN; 1588 if (compat20) { 1589 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1590 packet_put_int(c->remote_id); 1591 packet_put_int(c->self); 1592 packet_put_int(c->local_window); 1593 packet_put_int(c->local_maxpacket); 1594 } else { 1595 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1596 packet_put_int(c->remote_id); 1597 packet_put_int(c->self); 1598 } 1599 } else { 1600 debug("channel %d: connection failed: %s", 1601 c->self, strerror(err)); 1602 /* Try next address, if any */ 1603 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1604 close(c->sock); 1605 c->sock = c->rfd = c->wfd = sock; 1606 channel_max_fd = channel_find_maxfd(); 1607 return; 1608 } 1609 /* Exhausted all addresses */ 1610 error("connect_to %.100s port %d: failed.", 1611 c->connect_ctx.host, c->connect_ctx.port); 1612 channel_connect_ctx_free(&c->connect_ctx); 1613 if (compat20) { 1614 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1615 packet_put_int(c->remote_id); 1616 packet_put_int(SSH2_OPEN_CONNECT_FAILED); 1617 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1618 packet_put_cstring(strerror(err)); 1619 packet_put_cstring(""); 1620 } 1621 } else { 1622 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1623 packet_put_int(c->remote_id); 1624 } 1625 chan_mark_dead(c); 1626 } 1627 packet_send(); 1628 } 1629 } 1630 1631 /* ARGSUSED */ 1632 static int 1633 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset) 1634 { 1635 char buf[CHAN_RBUF]; 1636 int len, force; 1637 1638 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 1639 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) { 1640 errno = 0; 1641 len = read(c->rfd, buf, sizeof(buf)); 1642 if (len < 0 && (errno == EINTR || 1643 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 1644 return 1; 1645 #ifndef PTY_ZEROREAD 1646 if (len <= 0) { 1647 #else 1648 if ((!c->isatty && len <= 0) || 1649 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) { 1650 #endif 1651 debug2("channel %d: read<=0 rfd %d len %d", 1652 c->self, c->rfd, len); 1653 if (c->type != SSH_CHANNEL_OPEN) { 1654 debug2("channel %d: not open", c->self); 1655 chan_mark_dead(c); 1656 return -1; 1657 } else if (compat13) { 1658 buffer_clear(&c->output); 1659 c->type = SSH_CHANNEL_INPUT_DRAINING; 1660 debug2("channel %d: input draining.", c->self); 1661 } else { 1662 chan_read_failed(c); 1663 } 1664 return -1; 1665 } 1666 if (c->input_filter != NULL) { 1667 if (c->input_filter(c, buf, len) == -1) { 1668 debug2("channel %d: filter stops", c->self); 1669 chan_read_failed(c); 1670 } 1671 } else if (c->datagram) { 1672 buffer_put_string(&c->input, buf, len); 1673 } else { 1674 buffer_append(&c->input, buf, len); 1675 } 1676 } 1677 return 1; 1678 } 1679 1680 /* ARGSUSED */ 1681 static int 1682 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset) 1683 { 1684 struct termios tio; 1685 u_char *data = NULL, *buf; 1686 u_int dlen, olen = 0; 1687 int len; 1688 1689 /* Send buffered output data to the socket. */ 1690 if (c->wfd != -1 && 1691 FD_ISSET(c->wfd, writeset) && 1692 buffer_len(&c->output) > 0) { 1693 olen = buffer_len(&c->output); 1694 if (c->output_filter != NULL) { 1695 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) { 1696 debug2("channel %d: filter stops", c->self); 1697 if (c->type != SSH_CHANNEL_OPEN) 1698 chan_mark_dead(c); 1699 else 1700 chan_write_failed(c); 1701 return -1; 1702 } 1703 } else if (c->datagram) { 1704 buf = data = buffer_get_string(&c->output, &dlen); 1705 } else { 1706 buf = data = buffer_ptr(&c->output); 1707 dlen = buffer_len(&c->output); 1708 } 1709 1710 if (c->datagram) { 1711 /* ignore truncated writes, datagrams might get lost */ 1712 len = write(c->wfd, buf, dlen); 1713 xfree(data); 1714 if (len < 0 && (errno == EINTR || errno == EAGAIN || 1715 errno == EWOULDBLOCK)) 1716 return 1; 1717 if (len <= 0) { 1718 if (c->type != SSH_CHANNEL_OPEN) 1719 chan_mark_dead(c); 1720 else 1721 chan_write_failed(c); 1722 return -1; 1723 } 1724 goto out; 1725 } 1726 #ifdef _AIX 1727 /* XXX: Later AIX versions can't push as much data to tty */ 1728 if (compat20 && c->wfd_isatty) 1729 dlen = MIN(dlen, 8*1024); 1730 #endif 1731 1732 len = write(c->wfd, buf, dlen); 1733 if (len < 0 && 1734 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 1735 return 1; 1736 if (len <= 0) { 1737 if (c->type != SSH_CHANNEL_OPEN) { 1738 debug2("channel %d: not open", c->self); 1739 chan_mark_dead(c); 1740 return -1; 1741 } else if (compat13) { 1742 buffer_clear(&c->output); 1743 debug2("channel %d: input draining.", c->self); 1744 c->type = SSH_CHANNEL_INPUT_DRAINING; 1745 } else { 1746 chan_write_failed(c); 1747 } 1748 return -1; 1749 } 1750 #ifndef BROKEN_TCGETATTR_ICANON 1751 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') { 1752 if (tcgetattr(c->wfd, &tio) == 0 && 1753 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 1754 /* 1755 * Simulate echo to reduce the impact of 1756 * traffic analysis. We need to match the 1757 * size of a SSH2_MSG_CHANNEL_DATA message 1758 * (4 byte channel id + buf) 1759 */ 1760 packet_send_ignore(4 + len); 1761 packet_send(); 1762 } 1763 } 1764 #endif 1765 buffer_consume(&c->output, len); 1766 } 1767 out: 1768 if (compat20 && olen > 0) 1769 c->local_consumed += olen - buffer_len(&c->output); 1770 return 1; 1771 } 1772 1773 static int 1774 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset) 1775 { 1776 char buf[CHAN_RBUF]; 1777 int len; 1778 1779 /** XXX handle drain efd, too */ 1780 if (c->efd != -1) { 1781 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1782 FD_ISSET(c->efd, writeset) && 1783 buffer_len(&c->extended) > 0) { 1784 len = write(c->efd, buffer_ptr(&c->extended), 1785 buffer_len(&c->extended)); 1786 debug2("channel %d: written %d to efd %d", 1787 c->self, len, c->efd); 1788 if (len < 0 && (errno == EINTR || errno == EAGAIN || 1789 errno == EWOULDBLOCK)) 1790 return 1; 1791 if (len <= 0) { 1792 debug2("channel %d: closing write-efd %d", 1793 c->self, c->efd); 1794 channel_close_fd(&c->efd); 1795 } else { 1796 buffer_consume(&c->extended, len); 1797 c->local_consumed += len; 1798 } 1799 } else if (c->efd != -1 && 1800 (c->extended_usage == CHAN_EXTENDED_READ || 1801 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1802 (c->detach_close || FD_ISSET(c->efd, readset))) { 1803 len = read(c->efd, buf, sizeof(buf)); 1804 debug2("channel %d: read %d from efd %d", 1805 c->self, len, c->efd); 1806 if (len < 0 && (errno == EINTR || ((errno == EAGAIN || 1807 errno == EWOULDBLOCK) && !c->detach_close))) 1808 return 1; 1809 if (len <= 0) { 1810 debug2("channel %d: closing read-efd %d", 1811 c->self, c->efd); 1812 channel_close_fd(&c->efd); 1813 } else { 1814 if (c->extended_usage == CHAN_EXTENDED_IGNORE) { 1815 debug3("channel %d: discard efd", 1816 c->self); 1817 } else 1818 buffer_append(&c->extended, buf, len); 1819 } 1820 } 1821 } 1822 return 1; 1823 } 1824 1825 static int 1826 channel_check_window(Channel *c) 1827 { 1828 if (c->type == SSH_CHANNEL_OPEN && 1829 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 1830 ((c->local_window_max - c->local_window > 1831 c->local_maxpacket*3) || 1832 c->local_window < c->local_window_max/2) && 1833 c->local_consumed > 0) { 1834 u_int addition = 0; 1835 1836 /* Adjust max window size if we are in a dynamic environment. */ 1837 if (c->dynamic_window && c->tcpwinsz > c->local_window_max) { 1838 /* 1839 * Grow the window somewhat aggressively to maintain 1840 * pressure. 1841 */ 1842 addition = 1.5 * (c->tcpwinsz - c->local_window_max); 1843 c->local_window_max += addition; 1844 } 1845 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 1846 packet_put_int(c->remote_id); 1847 packet_put_int(c->local_consumed + addition); 1848 packet_send(); 1849 debug2("channel %d: window %d sent adjust %d", 1850 c->self, c->local_window, 1851 c->local_consumed); 1852 c->local_window += c->local_consumed + addition; 1853 c->local_consumed = 0; 1854 } 1855 return 1; 1856 } 1857 1858 static void 1859 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset) 1860 { 1861 channel_handle_rfd(c, readset, writeset); 1862 channel_handle_wfd(c, readset, writeset); 1863 if (!compat20) 1864 return; 1865 channel_handle_efd(c, readset, writeset); 1866 channel_check_window(c); 1867 } 1868 1869 static u_int 1870 read_mux(Channel *c, u_int need) 1871 { 1872 char buf[CHAN_RBUF]; 1873 int len; 1874 u_int rlen; 1875 1876 if (buffer_len(&c->input) < need) { 1877 rlen = need - buffer_len(&c->input); 1878 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF)); 1879 if (len <= 0) { 1880 if (errno != EINTR && errno != EAGAIN) { 1881 debug2("channel %d: ctl read<=0 rfd %d len %d", 1882 c->self, c->rfd, len); 1883 chan_read_failed(c); 1884 return 0; 1885 } 1886 } else 1887 buffer_append(&c->input, buf, len); 1888 } 1889 return buffer_len(&c->input); 1890 } 1891 1892 static void 1893 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1894 { 1895 u_int need; 1896 ssize_t len; 1897 1898 if (!compat20) 1899 fatal("%s: entered with !compat20", __func__); 1900 1901 if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) && 1902 (c->istate == CHAN_INPUT_OPEN || 1903 c->istate == CHAN_INPUT_WAIT_DRAIN)) { 1904 /* 1905 * Don't not read past the precise end of packets to 1906 * avoid disrupting fd passing. 1907 */ 1908 if (read_mux(c, 4) < 4) /* read header */ 1909 return; 1910 need = get_u32(buffer_ptr(&c->input)); 1911 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 1912 if (need > CHANNEL_MUX_MAX_PACKET) { 1913 debug2("channel %d: packet too big %u > %u", 1914 c->self, CHANNEL_MUX_MAX_PACKET, need); 1915 chan_rcvd_oclose(c); 1916 return; 1917 } 1918 if (read_mux(c, need + 4) < need + 4) /* read body */ 1919 return; 1920 if (c->mux_rcb(c) != 0) { 1921 debug("channel %d: mux_rcb failed", c->self); 1922 chan_mark_dead(c); 1923 return; 1924 } 1925 } 1926 1927 if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) && 1928 buffer_len(&c->output) > 0) { 1929 len = write(c->wfd, buffer_ptr(&c->output), 1930 buffer_len(&c->output)); 1931 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1932 return; 1933 if (len <= 0) { 1934 chan_mark_dead(c); 1935 return; 1936 } 1937 buffer_consume(&c->output, len); 1938 } 1939 } 1940 1941 static void 1942 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset) 1943 { 1944 Channel *nc; 1945 struct sockaddr_storage addr; 1946 socklen_t addrlen; 1947 int newsock; 1948 uid_t euid; 1949 gid_t egid; 1950 1951 if (!FD_ISSET(c->sock, readset)) 1952 return; 1953 1954 debug("multiplexing control connection"); 1955 1956 /* 1957 * Accept connection on control socket 1958 */ 1959 memset(&addr, 0, sizeof(addr)); 1960 addrlen = sizeof(addr); 1961 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 1962 &addrlen)) == -1) { 1963 error("%s accept: %s", __func__, strerror(errno)); 1964 return; 1965 } 1966 1967 if (getpeereid(newsock, &euid, &egid) < 0) { 1968 error("%s getpeereid failed: %s", __func__, 1969 strerror(errno)); 1970 close(newsock); 1971 return; 1972 } 1973 if ((euid != 0) && (getuid() != euid)) { 1974 error("multiplex uid mismatch: peer euid %u != uid %u", 1975 (u_int)euid, (u_int)getuid()); 1976 close(newsock); 1977 return; 1978 } 1979 nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT, 1980 newsock, newsock, -1, c->local_window_max, 1981 c->local_maxpacket, 0, "mux-control", 1); 1982 nc->mux_rcb = c->mux_rcb; 1983 debug3("%s: new mux channel %d fd %d", __func__, 1984 nc->self, nc->sock); 1985 /* establish state */ 1986 nc->mux_rcb(nc); 1987 /* mux state transitions must not elicit protocol messages */ 1988 nc->flags |= CHAN_LOCAL; 1989 } 1990 1991 /* ARGSUSED */ 1992 static void 1993 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset) 1994 { 1995 int len; 1996 1997 /* Send buffered output data to the socket. */ 1998 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { 1999 len = write(c->sock, buffer_ptr(&c->output), 2000 buffer_len(&c->output)); 2001 if (len <= 0) 2002 buffer_clear(&c->output); 2003 else 2004 buffer_consume(&c->output, len); 2005 } 2006 } 2007 2008 static void 2009 channel_handler_init_20(void) 2010 { 2011 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2012 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2013 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2014 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2015 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2016 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2017 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2018 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2019 channel_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2020 channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2021 2022 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2023 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2024 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2025 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2026 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2027 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2028 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2029 channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2030 channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2031 } 2032 2033 static void 2034 channel_handler_init_13(void) 2035 { 2036 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; 2037 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; 2038 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2039 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2040 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2041 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; 2042 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; 2043 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2044 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2045 2046 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2047 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2048 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2049 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2050 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; 2051 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2052 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2053 } 2054 2055 static void 2056 channel_handler_init_15(void) 2057 { 2058 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2059 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2060 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2061 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2062 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2063 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2064 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2065 2066 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2067 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2068 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2069 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2070 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2071 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2072 } 2073 2074 static void 2075 channel_handler_init(void) 2076 { 2077 int i; 2078 2079 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { 2080 channel_pre[i] = NULL; 2081 channel_post[i] = NULL; 2082 } 2083 if (compat20) 2084 channel_handler_init_20(); 2085 else if (compat13) 2086 channel_handler_init_13(); 2087 else 2088 channel_handler_init_15(); 2089 } 2090 2091 /* gc dead channels */ 2092 static void 2093 channel_garbage_collect(Channel *c) 2094 { 2095 if (c == NULL) 2096 return; 2097 if (c->detach_user != NULL) { 2098 if (!chan_is_dead(c, c->detach_close)) 2099 return; 2100 debug2("channel %d: gc: notify user", c->self); 2101 c->detach_user(c->self, NULL); 2102 /* if we still have a callback */ 2103 if (c->detach_user != NULL) 2104 return; 2105 debug2("channel %d: gc: user detached", c->self); 2106 } 2107 if (!chan_is_dead(c, 1)) 2108 return; 2109 debug2("channel %d: garbage collecting", c->self); 2110 channel_free(c); 2111 } 2112 2113 static void 2114 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset) 2115 { 2116 static int did_init = 0; 2117 u_int i, oalloc; 2118 Channel *c; 2119 2120 if (!did_init) { 2121 channel_handler_init(); 2122 did_init = 1; 2123 } 2124 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) { 2125 c = channels[i]; 2126 if (c == NULL) 2127 continue; 2128 if (c->delayed) { 2129 if (ftab == channel_pre) 2130 c->delayed = 0; 2131 else 2132 continue; 2133 } 2134 if (ftab[c->type] != NULL) 2135 (*ftab[c->type])(c, readset, writeset); 2136 channel_garbage_collect(c); 2137 } 2138 } 2139 2140 /* 2141 * Allocate/update select bitmasks and add any bits relevant to channels in 2142 * select bitmasks. 2143 */ 2144 void 2145 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, 2146 u_int *nallocp, int rekeying) 2147 { 2148 u_int n, sz, nfdset; 2149 2150 n = MAX(*maxfdp, channel_max_fd); 2151 2152 nfdset = howmany(n+1, NFDBITS); 2153 /* Explicitly test here, because xrealloc isn't always called */ 2154 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask)) 2155 fatal("channel_prepare_select: max_fd (%d) is too large", n); 2156 sz = nfdset * sizeof(fd_mask); 2157 2158 /* perhaps check sz < nalloc/2 and shrink? */ 2159 if (*readsetp == NULL || sz > *nallocp) { 2160 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask)); 2161 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask)); 2162 *nallocp = sz; 2163 } 2164 *maxfdp = n; 2165 memset(*readsetp, 0, sz); 2166 memset(*writesetp, 0, sz); 2167 2168 if (!rekeying) 2169 channel_handler(channel_pre, *readsetp, *writesetp); 2170 } 2171 2172 /* 2173 * After select, perform any appropriate operations for channels which have 2174 * events pending. 2175 */ 2176 void 2177 channel_after_select(fd_set *readset, fd_set *writeset) 2178 { 2179 channel_handler(channel_post, readset, writeset); 2180 } 2181 2182 2183 /* If there is data to send to the connection, enqueue some of it now. */ 2184 void 2185 channel_output_poll(void) 2186 { 2187 Channel *c; 2188 u_int i, len; 2189 2190 for (i = 0; i < channels_alloc; i++) { 2191 c = channels[i]; 2192 if (c == NULL) 2193 continue; 2194 2195 /* 2196 * We are only interested in channels that can have buffered 2197 * incoming data. 2198 */ 2199 if (compat13) { 2200 if (c->type != SSH_CHANNEL_OPEN && 2201 c->type != SSH_CHANNEL_INPUT_DRAINING) 2202 continue; 2203 } else { 2204 if (c->type != SSH_CHANNEL_OPEN) 2205 continue; 2206 } 2207 if (compat20 && 2208 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2209 /* XXX is this true? */ 2210 debug3("channel %d: will not send data after close", c->self); 2211 continue; 2212 } 2213 2214 /* Get the amount of buffered data for this channel. */ 2215 if ((c->istate == CHAN_INPUT_OPEN || 2216 c->istate == CHAN_INPUT_WAIT_DRAIN) && 2217 (len = buffer_len(&c->input)) > 0) { 2218 if (c->datagram) { 2219 if (len > 0) { 2220 u_char *data; 2221 u_int dlen; 2222 2223 data = buffer_get_string(&c->input, 2224 &dlen); 2225 if (dlen > c->remote_window || 2226 dlen > c->remote_maxpacket) { 2227 debug("channel %d: datagram " 2228 "too big for channel", 2229 c->self); 2230 xfree(data); 2231 continue; 2232 } 2233 packet_start(SSH2_MSG_CHANNEL_DATA); 2234 packet_put_int(c->remote_id); 2235 packet_put_string(data, dlen); 2236 packet_send(); 2237 c->remote_window -= dlen + 4; 2238 xfree(data); 2239 } 2240 continue; 2241 } 2242 /* 2243 * Send some data for the other side over the secure 2244 * connection. 2245 */ 2246 if (compat20) { 2247 if (len > c->remote_window) 2248 len = c->remote_window; 2249 if (len > c->remote_maxpacket) 2250 len = c->remote_maxpacket; 2251 } else { 2252 if (packet_is_interactive()) { 2253 if (len > 1024) 2254 len = 512; 2255 } else { 2256 /* Keep the packets at reasonable size. */ 2257 if (len > packet_get_maxsize()/2) 2258 len = packet_get_maxsize()/2; 2259 } 2260 } 2261 if (len > 0) { 2262 packet_start(compat20 ? 2263 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); 2264 packet_put_int(c->remote_id); 2265 packet_put_string(buffer_ptr(&c->input), len); 2266 packet_send(); 2267 buffer_consume(&c->input, len); 2268 c->remote_window -= len; 2269 } 2270 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2271 if (compat13) 2272 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); 2273 /* 2274 * input-buffer is empty and read-socket shutdown: 2275 * tell peer, that we will not send more data: send IEOF. 2276 * hack for extended data: delay EOF if EFD still in use. 2277 */ 2278 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2279 debug2("channel %d: ibuf_empty delayed efd %d/(%d)", 2280 c->self, c->efd, buffer_len(&c->extended)); 2281 else 2282 chan_ibuf_empty(c); 2283 } 2284 /* Send extended data, i.e. stderr */ 2285 if (compat20 && 2286 !(c->flags & CHAN_EOF_SENT) && 2287 c->remote_window > 0 && 2288 (len = buffer_len(&c->extended)) > 0 && 2289 c->extended_usage == CHAN_EXTENDED_READ) { 2290 debug2("channel %d: rwin %u elen %u euse %d", 2291 c->self, c->remote_window, buffer_len(&c->extended), 2292 c->extended_usage); 2293 if (len > c->remote_window) 2294 len = c->remote_window; 2295 if (len > c->remote_maxpacket) 2296 len = c->remote_maxpacket; 2297 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); 2298 packet_put_int(c->remote_id); 2299 packet_put_int(SSH2_EXTENDED_DATA_STDERR); 2300 packet_put_string(buffer_ptr(&c->extended), len); 2301 packet_send(); 2302 buffer_consume(&c->extended, len); 2303 c->remote_window -= len; 2304 debug2("channel %d: sent ext data %d", c->self, len); 2305 } 2306 } 2307 } 2308 2309 2310 /* -- protocol input */ 2311 2312 /* ARGSUSED */ 2313 void 2314 channel_input_data(int type, u_int32_t seq, void *ctxt) 2315 { 2316 int id; 2317 char *data; 2318 u_int data_len, win_len; 2319 Channel *c; 2320 2321 /* Get the channel number and verify it. */ 2322 id = packet_get_int(); 2323 c = channel_lookup(id); 2324 if (c == NULL) 2325 packet_disconnect("Received data for nonexistent channel %d.", id); 2326 2327 /* Ignore any data for non-open channels (might happen on close) */ 2328 if (c->type != SSH_CHANNEL_OPEN && 2329 c->type != SSH_CHANNEL_X11_OPEN) 2330 return; 2331 2332 /* Get the data. */ 2333 data = packet_get_string_ptr(&data_len); 2334 win_len = data_len; 2335 if (c->datagram) 2336 win_len += 4; /* string length header */ 2337 2338 /* 2339 * Ignore data for protocol > 1.3 if output end is no longer open. 2340 * For protocol 2 the sending side is reducing its window as it sends 2341 * data, so we must 'fake' consumption of the data in order to ensure 2342 * that window updates are sent back. Otherwise the connection might 2343 * deadlock. 2344 */ 2345 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { 2346 if (compat20) { 2347 c->local_window -= win_len; 2348 c->local_consumed += win_len; 2349 } 2350 return; 2351 } 2352 2353 if (compat20) { 2354 if (win_len > c->local_maxpacket) { 2355 logit("channel %d: rcvd big packet %d, maxpack %d", 2356 c->self, win_len, c->local_maxpacket); 2357 } 2358 if (win_len > c->local_window) { 2359 logit("channel %d: rcvd too much data %d, win %d", 2360 c->self, win_len, c->local_window); 2361 return; 2362 } 2363 c->local_window -= win_len; 2364 } 2365 if (c->datagram) 2366 buffer_put_string(&c->output, data, data_len); 2367 else 2368 buffer_append(&c->output, data, data_len); 2369 packet_check_eom(); 2370 } 2371 2372 /* ARGSUSED */ 2373 void 2374 channel_input_extended_data(int type, u_int32_t seq, void *ctxt) 2375 { 2376 int id; 2377 char *data; 2378 u_int data_len, tcode; 2379 Channel *c; 2380 2381 /* Get the channel number and verify it. */ 2382 id = packet_get_int(); 2383 c = channel_lookup(id); 2384 2385 if (c == NULL) 2386 packet_disconnect("Received extended_data for bad channel %d.", id); 2387 if (c->type != SSH_CHANNEL_OPEN) { 2388 logit("channel %d: ext data for non open", id); 2389 return; 2390 } 2391 if (c->flags & CHAN_EOF_RCVD) { 2392 if (datafellows & SSH_BUG_EXTEOF) 2393 debug("channel %d: accepting ext data after eof", id); 2394 else 2395 packet_disconnect("Received extended_data after EOF " 2396 "on channel %d.", id); 2397 } 2398 tcode = packet_get_int(); 2399 if (c->efd == -1 || 2400 c->extended_usage != CHAN_EXTENDED_WRITE || 2401 tcode != SSH2_EXTENDED_DATA_STDERR) { 2402 logit("channel %d: bad ext data", c->self); 2403 return; 2404 } 2405 data = packet_get_string(&data_len); 2406 packet_check_eom(); 2407 if (data_len > c->local_window) { 2408 logit("channel %d: rcvd too much extended_data %d, win %d", 2409 c->self, data_len, c->local_window); 2410 xfree(data); 2411 return; 2412 } 2413 debug2("channel %d: rcvd ext data %d", c->self, data_len); 2414 c->local_window -= data_len; 2415 buffer_append(&c->extended, data, data_len); 2416 xfree(data); 2417 } 2418 2419 /* ARGSUSED */ 2420 void 2421 channel_input_ieof(int type, u_int32_t seq, void *ctxt) 2422 { 2423 int id; 2424 Channel *c; 2425 2426 id = packet_get_int(); 2427 packet_check_eom(); 2428 c = channel_lookup(id); 2429 if (c == NULL) 2430 packet_disconnect("Received ieof for nonexistent channel %d.", id); 2431 chan_rcvd_ieof(c); 2432 2433 /* XXX force input close */ 2434 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 2435 debug("channel %d: FORCE input drain", c->self); 2436 c->istate = CHAN_INPUT_WAIT_DRAIN; 2437 if (buffer_len(&c->input) == 0) 2438 chan_ibuf_empty(c); 2439 } 2440 2441 } 2442 2443 /* ARGSUSED */ 2444 void 2445 channel_input_close(int type, u_int32_t seq, void *ctxt) 2446 { 2447 int id; 2448 Channel *c; 2449 2450 id = packet_get_int(); 2451 packet_check_eom(); 2452 c = channel_lookup(id); 2453 if (c == NULL) 2454 packet_disconnect("Received close for nonexistent channel %d.", id); 2455 2456 /* 2457 * Send a confirmation that we have closed the channel and no more 2458 * data is coming for it. 2459 */ 2460 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); 2461 packet_put_int(c->remote_id); 2462 packet_send(); 2463 2464 /* 2465 * If the channel is in closed state, we have sent a close request, 2466 * and the other side will eventually respond with a confirmation. 2467 * Thus, we cannot free the channel here, because then there would be 2468 * no-one to receive the confirmation. The channel gets freed when 2469 * the confirmation arrives. 2470 */ 2471 if (c->type != SSH_CHANNEL_CLOSED) { 2472 /* 2473 * Not a closed channel - mark it as draining, which will 2474 * cause it to be freed later. 2475 */ 2476 buffer_clear(&c->input); 2477 c->type = SSH_CHANNEL_OUTPUT_DRAINING; 2478 } 2479 } 2480 2481 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ 2482 /* ARGSUSED */ 2483 void 2484 channel_input_oclose(int type, u_int32_t seq, void *ctxt) 2485 { 2486 int id = packet_get_int(); 2487 Channel *c = channel_lookup(id); 2488 2489 packet_check_eom(); 2490 if (c == NULL) 2491 packet_disconnect("Received oclose for nonexistent channel %d.", id); 2492 chan_rcvd_oclose(c); 2493 } 2494 2495 /* ARGSUSED */ 2496 void 2497 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) 2498 { 2499 int id = packet_get_int(); 2500 Channel *c = channel_lookup(id); 2501 2502 packet_check_eom(); 2503 if (c == NULL) 2504 packet_disconnect("Received close confirmation for " 2505 "out-of-range channel %d.", id); 2506 if (c->type != SSH_CHANNEL_CLOSED) 2507 packet_disconnect("Received close confirmation for " 2508 "non-closed channel %d (type %d).", id, c->type); 2509 channel_free(c); 2510 } 2511 2512 /* ARGSUSED */ 2513 void 2514 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) 2515 { 2516 int id, remote_id; 2517 Channel *c; 2518 2519 id = packet_get_int(); 2520 c = channel_lookup(id); 2521 2522 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2523 packet_disconnect("Received open confirmation for " 2524 "non-opening channel %d.", id); 2525 remote_id = packet_get_int(); 2526 /* Record the remote channel number and mark that the channel is now open. */ 2527 c->remote_id = remote_id; 2528 c->type = SSH_CHANNEL_OPEN; 2529 2530 if (compat20) { 2531 c->remote_window = packet_get_int(); 2532 c->remote_maxpacket = packet_get_int(); 2533 if (c->open_confirm) { 2534 debug2("callback start"); 2535 c->open_confirm(c->self, 1, c->open_confirm_ctx); 2536 debug2("callback done"); 2537 } 2538 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 2539 c->remote_window, c->remote_maxpacket); 2540 } 2541 packet_check_eom(); 2542 } 2543 2544 static char * 2545 reason2txt(int reason) 2546 { 2547 switch (reason) { 2548 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 2549 return "administratively prohibited"; 2550 case SSH2_OPEN_CONNECT_FAILED: 2551 return "connect failed"; 2552 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 2553 return "unknown channel type"; 2554 case SSH2_OPEN_RESOURCE_SHORTAGE: 2555 return "resource shortage"; 2556 } 2557 return "unknown reason"; 2558 } 2559 2560 /* ARGSUSED */ 2561 void 2562 channel_input_open_failure(int type, u_int32_t seq, void *ctxt) 2563 { 2564 int id, reason; 2565 char *msg = NULL, *lang = NULL; 2566 Channel *c; 2567 2568 id = packet_get_int(); 2569 c = channel_lookup(id); 2570 2571 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2572 packet_disconnect("Received open failure for " 2573 "non-opening channel %d.", id); 2574 if (compat20) { 2575 reason = packet_get_int(); 2576 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 2577 msg = packet_get_string(NULL); 2578 lang = packet_get_string(NULL); 2579 } 2580 logit("channel %d: open failed: %s%s%s", id, 2581 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 2582 if (msg != NULL) 2583 xfree(msg); 2584 if (lang != NULL) 2585 xfree(lang); 2586 if (c->open_confirm) { 2587 debug2("callback start"); 2588 c->open_confirm(c->self, 0, c->open_confirm_ctx); 2589 debug2("callback done"); 2590 } 2591 } 2592 packet_check_eom(); 2593 /* Schedule the channel for cleanup/deletion. */ 2594 chan_mark_dead(c); 2595 } 2596 2597 /* ARGSUSED */ 2598 void 2599 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) 2600 { 2601 Channel *c; 2602 int id; 2603 u_int adjust; 2604 2605 if (!compat20) 2606 return; 2607 2608 /* Get the channel number and verify it. */ 2609 id = packet_get_int(); 2610 c = channel_lookup(id); 2611 2612 if (c == NULL) { 2613 logit("Received window adjust for non-open channel %d.", id); 2614 return; 2615 } 2616 adjust = packet_get_int(); 2617 packet_check_eom(); 2618 debug2("channel %d: rcvd adjust %u", id, adjust); 2619 c->remote_window += adjust; 2620 } 2621 2622 /* ARGSUSED */ 2623 void 2624 channel_input_port_open(int type, u_int32_t seq, void *ctxt) 2625 { 2626 Channel *c = NULL; 2627 u_short host_port; 2628 char *host, *originator_string; 2629 int remote_id; 2630 2631 remote_id = packet_get_int(); 2632 host = packet_get_string(NULL); 2633 host_port = packet_get_int(); 2634 2635 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 2636 originator_string = packet_get_string(NULL); 2637 } else { 2638 originator_string = xstrdup("unknown (remote did not supply name)"); 2639 } 2640 packet_check_eom(); 2641 c = channel_connect_to(host, host_port, 2642 "connected socket", originator_string); 2643 xfree(originator_string); 2644 xfree(host); 2645 if (c == NULL) { 2646 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 2647 packet_put_int(remote_id); 2648 packet_send(); 2649 } else 2650 c->remote_id = remote_id; 2651 } 2652 2653 /* ARGSUSED */ 2654 void 2655 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt) 2656 { 2657 Channel *c; 2658 struct channel_confirm *cc; 2659 int id; 2660 2661 /* Reset keepalive timeout */ 2662 packet_set_alive_timeouts(0); 2663 2664 id = packet_get_int(); 2665 packet_check_eom(); 2666 2667 debug2("channel_input_status_confirm: type %d id %d", type, id); 2668 2669 if ((c = channel_lookup(id)) == NULL) { 2670 logit("channel_input_status_confirm: %d: unknown", id); 2671 return; 2672 } 2673 ; 2674 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 2675 return; 2676 cc->cb(type, c, cc->ctx); 2677 TAILQ_REMOVE(&c->status_confirms, cc, entry); 2678 bzero(cc, sizeof(*cc)); 2679 xfree(cc); 2680 } 2681 2682 /* -- tcp forwarding */ 2683 2684 void 2685 channel_set_af(int af) 2686 { 2687 IPv4or6 = af; 2688 } 2689 2690 void 2691 channel_set_hpn(int disabled, u_int buf_size) 2692 { 2693 hpn_disabled = disabled; 2694 buffer_size = buf_size; 2695 debug("HPN Disabled: %d, HPN Buffer Size: %d", 2696 hpn_disabled, buffer_size); 2697 } 2698 2699 static int 2700 channel_setup_fwd_listener(int type, const char *listen_addr, 2701 u_short listen_port, int *allocated_listen_port, 2702 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2703 { 2704 Channel *c; 2705 int sock, r, success = 0, wildcard = 0, is_client; 2706 struct addrinfo hints, *ai, *aitop; 2707 const char *host, *addr; 2708 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 2709 in_port_t *lport_p; 2710 2711 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 2712 listen_addr : host_to_connect; 2713 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 2714 2715 if (host == NULL) { 2716 error("No forward host name."); 2717 return 0; 2718 } 2719 if (strlen(host) >= NI_MAXHOST) { 2720 error("Forward host name too long."); 2721 return 0; 2722 } 2723 2724 /* 2725 * Determine whether or not a port forward listens to loopback, 2726 * specified address or wildcard. On the client, a specified bind 2727 * address will always override gateway_ports. On the server, a 2728 * gateway_ports of 1 (``yes'') will override the client's 2729 * specification and force a wildcard bind, whereas a value of 2 2730 * (``clientspecified'') will bind to whatever address the client 2731 * asked for. 2732 * 2733 * Special-case listen_addrs are: 2734 * 2735 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 2736 * "" (empty string), "*" -> wildcard v4/v6 2737 * "localhost" -> loopback v4/v6 2738 */ 2739 addr = NULL; 2740 if (listen_addr == NULL) { 2741 /* No address specified: default to gateway_ports setting */ 2742 if (gateway_ports) 2743 wildcard = 1; 2744 } else if (gateway_ports || is_client) { 2745 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 2746 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 2747 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 2748 (!is_client && gateway_ports == 1)) 2749 wildcard = 1; 2750 else if (strcmp(listen_addr, "localhost") != 0) 2751 addr = listen_addr; 2752 } 2753 2754 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s", 2755 type, wildcard, (addr == NULL) ? "NULL" : addr); 2756 2757 /* 2758 * getaddrinfo returns a loopback address if the hostname is 2759 * set to NULL and hints.ai_flags is not AI_PASSIVE 2760 */ 2761 memset(&hints, 0, sizeof(hints)); 2762 hints.ai_family = IPv4or6; 2763 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 2764 hints.ai_socktype = SOCK_STREAM; 2765 snprintf(strport, sizeof strport, "%d", listen_port); 2766 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 2767 if (addr == NULL) { 2768 /* This really shouldn't happen */ 2769 packet_disconnect("getaddrinfo: fatal error: %s", 2770 ssh_gai_strerror(r)); 2771 } else { 2772 error("channel_setup_fwd_listener: " 2773 "getaddrinfo(%.64s): %s", addr, 2774 ssh_gai_strerror(r)); 2775 } 2776 return 0; 2777 } 2778 if (allocated_listen_port != NULL) 2779 *allocated_listen_port = 0; 2780 for (ai = aitop; ai; ai = ai->ai_next) { 2781 switch (ai->ai_family) { 2782 case AF_INET: 2783 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 2784 sin_port; 2785 break; 2786 case AF_INET6: 2787 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 2788 sin6_port; 2789 break; 2790 default: 2791 continue; 2792 } 2793 /* 2794 * If allocating a port for -R forwards, then use the 2795 * same port for all address families. 2796 */ 2797 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 && 2798 allocated_listen_port != NULL && *allocated_listen_port > 0) 2799 *lport_p = htons(*allocated_listen_port); 2800 2801 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 2802 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 2803 error("channel_setup_fwd_listener: getnameinfo failed"); 2804 continue; 2805 } 2806 /* Create a port to listen for the host. */ 2807 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 2808 if (sock < 0) { 2809 /* this is no error since kernel may not support ipv6 */ 2810 verbose("socket: %.100s", strerror(errno)); 2811 continue; 2812 } 2813 2814 channel_set_reuseaddr(sock); 2815 if (ai->ai_family == AF_INET6) 2816 sock_set_v6only(sock); 2817 2818 debug("Local forwarding listening on %s port %s.", 2819 ntop, strport); 2820 2821 /* Bind the socket to the address. */ 2822 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 2823 /* address can be in use ipv6 address is already bound */ 2824 if (!ai->ai_next) 2825 error("bind: %.100s", strerror(errno)); 2826 else 2827 verbose("bind: %.100s", strerror(errno)); 2828 2829 close(sock); 2830 continue; 2831 } 2832 /* Start listening for connections on the socket. */ 2833 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 2834 error("listen: %.100s", strerror(errno)); 2835 close(sock); 2836 continue; 2837 } 2838 2839 /* 2840 * listen_port == 0 requests a dynamically allocated port - 2841 * record what we got. 2842 */ 2843 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 && 2844 allocated_listen_port != NULL && 2845 *allocated_listen_port == 0) { 2846 *allocated_listen_port = get_sock_port(sock, 1); 2847 debug("Allocated listen port %d", 2848 *allocated_listen_port); 2849 } 2850 2851 /* 2852 * Allocate a channel number for the socket. Explicitly test 2853 * for hpn disabled option. If true use smaller window size. 2854 */ 2855 if (hpn_disabled) 2856 c = channel_new("port listener", type, sock, sock, -1, 2857 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 2858 0, "port listener", 1); 2859 else 2860 c = channel_new("port listener", type, sock, sock, -1, 2861 buffer_size, CHAN_TCP_PACKET_DEFAULT, 2862 0, "port listener", 1); 2863 c->path = xstrdup(host); 2864 c->host_port = port_to_connect; 2865 c->listening_port = listen_port; 2866 success = 1; 2867 } 2868 if (success == 0) 2869 error("channel_setup_fwd_listener: cannot listen to port: %d", 2870 listen_port); 2871 freeaddrinfo(aitop); 2872 return success; 2873 } 2874 2875 int 2876 channel_cancel_rport_listener(const char *host, u_short port) 2877 { 2878 u_int i; 2879 int found = 0; 2880 2881 for (i = 0; i < channels_alloc; i++) { 2882 Channel *c = channels[i]; 2883 2884 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER && 2885 strcmp(c->path, host) == 0 && c->listening_port == port) { 2886 debug2("%s: close channel %d", __func__, i); 2887 channel_free(c); 2888 found = 1; 2889 } 2890 } 2891 2892 return (found); 2893 } 2894 2895 /* protocol local port fwd, used by ssh (and sshd in v1) */ 2896 int 2897 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port, 2898 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2899 { 2900 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, 2901 listen_host, listen_port, NULL, host_to_connect, port_to_connect, 2902 gateway_ports); 2903 } 2904 2905 /* protocol v2 remote port fwd, used by sshd */ 2906 int 2907 channel_setup_remote_fwd_listener(const char *listen_address, 2908 u_short listen_port, int *allocated_listen_port, int gateway_ports) 2909 { 2910 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, 2911 listen_address, listen_port, allocated_listen_port, 2912 NULL, 0, gateway_ports); 2913 } 2914 2915 /* 2916 * Initiate forwarding of connections to port "port" on remote host through 2917 * the secure channel to host:port from local side. 2918 */ 2919 2920 int 2921 channel_request_remote_forwarding(const char *listen_host, u_short listen_port, 2922 const char *host_to_connect, u_short port_to_connect) 2923 { 2924 int type, success = 0; 2925 2926 /* Send the forward request to the remote side. */ 2927 if (compat20) { 2928 const char *address_to_bind; 2929 if (listen_host == NULL) { 2930 if (datafellows & SSH_BUG_RFWD_ADDR) 2931 address_to_bind = "127.0.0.1"; 2932 else 2933 address_to_bind = "localhost"; 2934 } else if (*listen_host == '\0' || 2935 strcmp(listen_host, "*") == 0) { 2936 if (datafellows & SSH_BUG_RFWD_ADDR) 2937 address_to_bind = "0.0.0.0"; 2938 else 2939 address_to_bind = ""; 2940 } else 2941 address_to_bind = listen_host; 2942 2943 packet_start(SSH2_MSG_GLOBAL_REQUEST); 2944 packet_put_cstring("tcpip-forward"); 2945 packet_put_char(1); /* boolean: want reply */ 2946 packet_put_cstring(address_to_bind); 2947 packet_put_int(listen_port); 2948 packet_send(); 2949 packet_write_wait(); 2950 /* Assume that server accepts the request */ 2951 success = 1; 2952 } else { 2953 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); 2954 packet_put_int(listen_port); 2955 packet_put_cstring(host_to_connect); 2956 packet_put_int(port_to_connect); 2957 packet_send(); 2958 packet_write_wait(); 2959 2960 /* Wait for response from the remote side. */ 2961 type = packet_read(); 2962 switch (type) { 2963 case SSH_SMSG_SUCCESS: 2964 success = 1; 2965 break; 2966 case SSH_SMSG_FAILURE: 2967 break; 2968 default: 2969 /* Unknown packet */ 2970 packet_disconnect("Protocol error for port forward request:" 2971 "received packet type %d.", type); 2972 } 2973 } 2974 if (success) { 2975 /* Record that connection to this host/port is permitted. */ 2976 permitted_opens = xrealloc(permitted_opens, 2977 num_permitted_opens + 1, sizeof(*permitted_opens)); 2978 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); 2979 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; 2980 permitted_opens[num_permitted_opens].listen_port = listen_port; 2981 num_permitted_opens++; 2982 } 2983 return (success ? 0 : -1); 2984 } 2985 2986 /* 2987 * Request cancellation of remote forwarding of connection host:port from 2988 * local side. 2989 */ 2990 void 2991 channel_request_rforward_cancel(const char *host, u_short port) 2992 { 2993 int i; 2994 2995 if (!compat20) 2996 return; 2997 2998 for (i = 0; i < num_permitted_opens; i++) { 2999 if (permitted_opens[i].host_to_connect != NULL && 3000 permitted_opens[i].listen_port == port) 3001 break; 3002 } 3003 if (i >= num_permitted_opens) { 3004 debug("%s: requested forward not found", __func__); 3005 return; 3006 } 3007 packet_start(SSH2_MSG_GLOBAL_REQUEST); 3008 packet_put_cstring("cancel-tcpip-forward"); 3009 packet_put_char(0); 3010 packet_put_cstring(host == NULL ? "" : host); 3011 packet_put_int(port); 3012 packet_send(); 3013 3014 permitted_opens[i].listen_port = 0; 3015 permitted_opens[i].port_to_connect = 0; 3016 xfree(permitted_opens[i].host_to_connect); 3017 permitted_opens[i].host_to_connect = NULL; 3018 } 3019 3020 /* 3021 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates 3022 * listening for the port, and sends back a success reply (or disconnect 3023 * message if there was an error). 3024 */ 3025 int 3026 channel_input_port_forward_request(int is_root, int gateway_ports) 3027 { 3028 u_short port, host_port; 3029 int success = 0; 3030 char *hostname; 3031 3032 /* Get arguments from the packet. */ 3033 port = packet_get_int(); 3034 hostname = packet_get_string(NULL); 3035 host_port = packet_get_int(); 3036 3037 #ifndef HAVE_CYGWIN 3038 /* 3039 * Check that an unprivileged user is not trying to forward a 3040 * privileged port. 3041 */ 3042 if (port < IPPORT_RESERVED && !is_root) 3043 packet_disconnect( 3044 "Requested forwarding of port %d but user is not root.", 3045 port); 3046 if (host_port == 0) 3047 packet_disconnect("Dynamic forwarding denied."); 3048 #endif 3049 3050 /* Initiate forwarding */ 3051 success = channel_setup_local_fwd_listener(NULL, port, hostname, 3052 host_port, gateway_ports); 3053 3054 /* Free the argument string. */ 3055 xfree(hostname); 3056 3057 return (success ? 0 : -1); 3058 } 3059 3060 /* 3061 * Permits opening to any host/port if permitted_opens[] is empty. This is 3062 * usually called by the server, because the user could connect to any port 3063 * anyway, and the server has no way to know but to trust the client anyway. 3064 */ 3065 void 3066 channel_permit_all_opens(void) 3067 { 3068 if (num_permitted_opens == 0) 3069 all_opens_permitted = 1; 3070 } 3071 3072 void 3073 channel_add_permitted_opens(char *host, int port) 3074 { 3075 debug("allow port forwarding to host %s port %d", host, port); 3076 3077 permitted_opens = xrealloc(permitted_opens, 3078 num_permitted_opens + 1, sizeof(*permitted_opens)); 3079 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); 3080 permitted_opens[num_permitted_opens].port_to_connect = port; 3081 num_permitted_opens++; 3082 3083 all_opens_permitted = 0; 3084 } 3085 3086 int 3087 channel_add_adm_permitted_opens(char *host, int port) 3088 { 3089 debug("config allows port forwarding to host %s port %d", host, port); 3090 3091 permitted_adm_opens = xrealloc(permitted_adm_opens, 3092 num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens)); 3093 permitted_adm_opens[num_adm_permitted_opens].host_to_connect 3094 = xstrdup(host); 3095 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port; 3096 return ++num_adm_permitted_opens; 3097 } 3098 3099 void 3100 channel_clear_permitted_opens(void) 3101 { 3102 int i; 3103 3104 for (i = 0; i < num_permitted_opens; i++) 3105 if (permitted_opens[i].host_to_connect != NULL) 3106 xfree(permitted_opens[i].host_to_connect); 3107 if (num_permitted_opens > 0) { 3108 xfree(permitted_opens); 3109 permitted_opens = NULL; 3110 } 3111 num_permitted_opens = 0; 3112 } 3113 3114 void 3115 channel_clear_adm_permitted_opens(void) 3116 { 3117 int i; 3118 3119 for (i = 0; i < num_adm_permitted_opens; i++) 3120 if (permitted_adm_opens[i].host_to_connect != NULL) 3121 xfree(permitted_adm_opens[i].host_to_connect); 3122 if (num_adm_permitted_opens > 0) { 3123 xfree(permitted_adm_opens); 3124 permitted_adm_opens = NULL; 3125 } 3126 num_adm_permitted_opens = 0; 3127 } 3128 3129 void 3130 channel_print_adm_permitted_opens(void) 3131 { 3132 int i; 3133 3134 printf("permitopen"); 3135 if (num_adm_permitted_opens == 0) { 3136 printf(" any\n"); 3137 return; 3138 } 3139 for (i = 0; i < num_adm_permitted_opens; i++) 3140 if (permitted_adm_opens[i].host_to_connect != NULL) 3141 printf(" %s:%d", permitted_adm_opens[i].host_to_connect, 3142 permitted_adm_opens[i].port_to_connect); 3143 printf("\n"); 3144 } 3145 3146 /* Try to start non-blocking connect to next host in cctx list */ 3147 static int 3148 connect_next(struct channel_connect *cctx) 3149 { 3150 int sock, saved_errno; 3151 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3152 3153 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 3154 if (cctx->ai->ai_family != AF_INET && 3155 cctx->ai->ai_family != AF_INET6) 3156 continue; 3157 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 3158 ntop, sizeof(ntop), strport, sizeof(strport), 3159 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3160 error("connect_next: getnameinfo failed"); 3161 continue; 3162 } 3163 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 3164 cctx->ai->ai_protocol)) == -1) { 3165 if (cctx->ai->ai_next == NULL) 3166 error("socket: %.100s", strerror(errno)); 3167 else 3168 verbose("socket: %.100s", strerror(errno)); 3169 continue; 3170 } 3171 if (set_nonblock(sock) == -1) 3172 fatal("%s: set_nonblock(%d)", __func__, sock); 3173 if (connect(sock, cctx->ai->ai_addr, 3174 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 3175 debug("connect_next: host %.100s ([%.100s]:%s): " 3176 "%.100s", cctx->host, ntop, strport, 3177 strerror(errno)); 3178 saved_errno = errno; 3179 close(sock); 3180 errno = saved_errno; 3181 continue; /* fail -- try next */ 3182 } 3183 debug("connect_next: host %.100s ([%.100s]:%s) " 3184 "in progress, fd=%d", cctx->host, ntop, strport, sock); 3185 cctx->ai = cctx->ai->ai_next; 3186 set_nodelay(sock); 3187 return sock; 3188 } 3189 return -1; 3190 } 3191 3192 static void 3193 channel_connect_ctx_free(struct channel_connect *cctx) 3194 { 3195 xfree(cctx->host); 3196 if (cctx->aitop) 3197 freeaddrinfo(cctx->aitop); 3198 bzero(cctx, sizeof(*cctx)); 3199 cctx->host = NULL; 3200 cctx->ai = cctx->aitop = NULL; 3201 } 3202 3203 /* Return CONNECTING channel to remote host, port */ 3204 static Channel * 3205 connect_to(const char *host, u_short port, char *ctype, char *rname) 3206 { 3207 struct addrinfo hints; 3208 int gaierr; 3209 int sock = -1; 3210 char strport[NI_MAXSERV]; 3211 struct channel_connect cctx; 3212 Channel *c; 3213 3214 memset(&cctx, 0, sizeof(cctx)); 3215 memset(&hints, 0, sizeof(hints)); 3216 hints.ai_family = IPv4or6; 3217 hints.ai_socktype = SOCK_STREAM; 3218 snprintf(strport, sizeof strport, "%d", port); 3219 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) { 3220 error("connect_to %.100s: unknown host (%s)", host, 3221 ssh_gai_strerror(gaierr)); 3222 return NULL; 3223 } 3224 3225 cctx.host = xstrdup(host); 3226 cctx.port = port; 3227 cctx.ai = cctx.aitop; 3228 3229 if ((sock = connect_next(&cctx)) == -1) { 3230 error("connect to %.100s port %d failed: %s", 3231 host, port, strerror(errno)); 3232 channel_connect_ctx_free(&cctx); 3233 return NULL; 3234 } 3235 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 3236 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 3237 c->connect_ctx = cctx; 3238 return c; 3239 } 3240 3241 Channel * 3242 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname) 3243 { 3244 int i; 3245 3246 for (i = 0; i < num_permitted_opens; i++) { 3247 if (permitted_opens[i].host_to_connect != NULL && 3248 permitted_opens[i].listen_port == listen_port) { 3249 return connect_to( 3250 permitted_opens[i].host_to_connect, 3251 permitted_opens[i].port_to_connect, ctype, rname); 3252 } 3253 } 3254 error("WARNING: Server requests forwarding for unknown listen_port %d", 3255 listen_port); 3256 return NULL; 3257 } 3258 3259 /* Check if connecting to that port is permitted and connect. */ 3260 Channel * 3261 channel_connect_to(const char *host, u_short port, char *ctype, char *rname) 3262 { 3263 int i, permit, permit_adm = 1; 3264 3265 permit = all_opens_permitted; 3266 if (!permit) { 3267 for (i = 0; i < num_permitted_opens; i++) 3268 if (permitted_opens[i].host_to_connect != NULL && 3269 permitted_opens[i].port_to_connect == port && 3270 strcmp(permitted_opens[i].host_to_connect, host) == 0) 3271 permit = 1; 3272 } 3273 3274 if (num_adm_permitted_opens > 0) { 3275 permit_adm = 0; 3276 for (i = 0; i < num_adm_permitted_opens; i++) 3277 if (permitted_adm_opens[i].host_to_connect != NULL && 3278 permitted_adm_opens[i].port_to_connect == port && 3279 strcmp(permitted_adm_opens[i].host_to_connect, host) 3280 == 0) 3281 permit_adm = 1; 3282 } 3283 3284 if (!permit || !permit_adm) { 3285 logit("Received request to connect to host %.100s port %d, " 3286 "but the request was denied.", host, port); 3287 return NULL; 3288 } 3289 return connect_to(host, port, ctype, rname); 3290 } 3291 3292 void 3293 channel_send_window_changes(void) 3294 { 3295 u_int i; 3296 struct winsize ws; 3297 3298 for (i = 0; i < channels_alloc; i++) { 3299 if (channels[i] == NULL || !channels[i]->client_tty || 3300 channels[i]->type != SSH_CHANNEL_OPEN) 3301 continue; 3302 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) 3303 continue; 3304 channel_request_start(i, "window-change", 0); 3305 packet_put_int((u_int)ws.ws_col); 3306 packet_put_int((u_int)ws.ws_row); 3307 packet_put_int((u_int)ws.ws_xpixel); 3308 packet_put_int((u_int)ws.ws_ypixel); 3309 packet_send(); 3310 } 3311 } 3312 3313 /* -- X11 forwarding */ 3314 3315 /* 3316 * Creates an internet domain socket for listening for X11 connections. 3317 * Returns 0 and a suitable display number for the DISPLAY variable 3318 * stored in display_numberp , or -1 if an error occurs. 3319 */ 3320 int 3321 x11_create_display_inet(int x11_display_offset, int x11_use_localhost, 3322 int single_connection, u_int *display_numberp, int **chanids) 3323 { 3324 Channel *nc = NULL; 3325 int display_number, sock; 3326 u_short port; 3327 struct addrinfo hints, *ai, *aitop; 3328 char strport[NI_MAXSERV]; 3329 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 3330 3331 if (chanids == NULL) 3332 return -1; 3333 3334 for (display_number = x11_display_offset; 3335 display_number < MAX_DISPLAYS; 3336 display_number++) { 3337 port = 6000 + display_number; 3338 memset(&hints, 0, sizeof(hints)); 3339 hints.ai_family = IPv4or6; 3340 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 3341 hints.ai_socktype = SOCK_STREAM; 3342 snprintf(strport, sizeof strport, "%d", port); 3343 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { 3344 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 3345 return -1; 3346 } 3347 for (ai = aitop; ai; ai = ai->ai_next) { 3348 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 3349 continue; 3350 sock = socket(ai->ai_family, ai->ai_socktype, 3351 ai->ai_protocol); 3352 if (sock < 0) { 3353 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 3354 #ifdef EPFNOSUPPORT 3355 && (errno != EPFNOSUPPORT) 3356 #endif 3357 ) { 3358 error("socket: %.100s", strerror(errno)); 3359 freeaddrinfo(aitop); 3360 return -1; 3361 } else { 3362 debug("x11_create_display_inet: Socket family %d not supported", 3363 ai->ai_family); 3364 continue; 3365 } 3366 } 3367 if (ai->ai_family == AF_INET6) 3368 sock_set_v6only(sock); 3369 if (x11_use_localhost) 3370 channel_set_reuseaddr(sock); 3371 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3372 debug2("bind port %d: %.100s", port, strerror(errno)); 3373 close(sock); 3374 3375 for (n = 0; n < num_socks; n++) { 3376 close(socks[n]); 3377 } 3378 num_socks = 0; 3379 break; 3380 } 3381 socks[num_socks++] = sock; 3382 if (num_socks == NUM_SOCKS) 3383 break; 3384 } 3385 freeaddrinfo(aitop); 3386 if (num_socks > 0) 3387 break; 3388 } 3389 if (display_number >= MAX_DISPLAYS) { 3390 error("Failed to allocate internet-domain X11 display socket."); 3391 return -1; 3392 } 3393 /* Start listening for connections on the socket. */ 3394 for (n = 0; n < num_socks; n++) { 3395 sock = socks[n]; 3396 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 3397 error("listen: %.100s", strerror(errno)); 3398 close(sock); 3399 return -1; 3400 } 3401 } 3402 3403 /* Allocate a channel for each socket. */ 3404 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 3405 for (n = 0; n < num_socks; n++) { 3406 sock = socks[n]; 3407 if (hpn_disabled) 3408 nc = channel_new("x11 listener", 3409 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 3410 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 3411 0, "X11 inet listener", 1); 3412 else 3413 nc = channel_new("x11 listener", 3414 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 3415 buffer_size, CHAN_X11_PACKET_DEFAULT, 3416 0, "X11 inet listener", 1); 3417 nc->single_connection = single_connection; 3418 (*chanids)[n] = nc->self; 3419 } 3420 (*chanids)[n] = -1; 3421 3422 /* Return the display number for the DISPLAY environment variable. */ 3423 *display_numberp = display_number; 3424 return (0); 3425 } 3426 3427 static int 3428 connect_local_xsocket_path(const char *pathname) 3429 { 3430 int sock; 3431 struct sockaddr_un addr; 3432 3433 sock = socket(AF_UNIX, SOCK_STREAM, 0); 3434 if (sock < 0) 3435 error("socket: %.100s", strerror(errno)); 3436 memset(&addr, 0, sizeof(addr)); 3437 addr.sun_family = AF_UNIX; 3438 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 3439 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 3440 return sock; 3441 close(sock); 3442 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 3443 return -1; 3444 } 3445 3446 static int 3447 connect_local_xsocket(u_int dnr) 3448 { 3449 char buf[1024]; 3450 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 3451 return connect_local_xsocket_path(buf); 3452 } 3453 3454 int 3455 x11_connect_display(void) 3456 { 3457 u_int display_number; 3458 const char *display; 3459 char buf[1024], *cp; 3460 struct addrinfo hints, *ai, *aitop; 3461 char strport[NI_MAXSERV]; 3462 int gaierr, sock = 0; 3463 3464 /* Try to open a socket for the local X server. */ 3465 display = getenv("DISPLAY"); 3466 if (!display) { 3467 error("DISPLAY not set."); 3468 return -1; 3469 } 3470 /* 3471 * Now we decode the value of the DISPLAY variable and make a 3472 * connection to the real X server. 3473 */ 3474 3475 /* Check if the display is from launchd. */ 3476 #ifdef __APPLE__ 3477 if (strncmp(display, "/tmp/launch", 11) == 0) { 3478 sock = connect_local_xsocket_path(display); 3479 if (sock < 0) 3480 return -1; 3481 3482 /* OK, we now have a connection to the display. */ 3483 return sock; 3484 } 3485 #endif 3486 /* 3487 * Check if it is a unix domain socket. Unix domain displays are in 3488 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 3489 */ 3490 if (strncmp(display, "unix:", 5) == 0 || 3491 display[0] == ':') { 3492 /* Connect to the unix domain socket. */ 3493 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) { 3494 error("Could not parse display number from DISPLAY: %.100s", 3495 display); 3496 return -1; 3497 } 3498 /* Create a socket. */ 3499 sock = connect_local_xsocket(display_number); 3500 if (sock < 0) 3501 return -1; 3502 3503 /* OK, we now have a connection to the display. */ 3504 return sock; 3505 } 3506 /* 3507 * Connect to an inet socket. The DISPLAY value is supposedly 3508 * hostname:d[.s], where hostname may also be numeric IP address. 3509 */ 3510 strlcpy(buf, display, sizeof(buf)); 3511 cp = strchr(buf, ':'); 3512 if (!cp) { 3513 error("Could not find ':' in DISPLAY: %.100s", display); 3514 return -1; 3515 } 3516 *cp = 0; 3517 /* buf now contains the host name. But first we parse the display number. */ 3518 if (sscanf(cp + 1, "%u", &display_number) != 1) { 3519 error("Could not parse display number from DISPLAY: %.100s", 3520 display); 3521 return -1; 3522 } 3523 3524 /* Look up the host address */ 3525 memset(&hints, 0, sizeof(hints)); 3526 hints.ai_family = IPv4or6; 3527 hints.ai_socktype = SOCK_STREAM; 3528 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 3529 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 3530 error("%.100s: unknown host. (%s)", buf, 3531 ssh_gai_strerror(gaierr)); 3532 return -1; 3533 } 3534 for (ai = aitop; ai; ai = ai->ai_next) { 3535 /* Create a socket. */ 3536 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3537 if (sock < 0) { 3538 debug2("socket: %.100s", strerror(errno)); 3539 continue; 3540 } 3541 /* Connect it to the display. */ 3542 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3543 debug2("connect %.100s port %u: %.100s", buf, 3544 6000 + display_number, strerror(errno)); 3545 close(sock); 3546 continue; 3547 } 3548 /* Success */ 3549 break; 3550 } 3551 freeaddrinfo(aitop); 3552 if (!ai) { 3553 error("connect %.100s port %u: %.100s", buf, 6000 + display_number, 3554 strerror(errno)); 3555 return -1; 3556 } 3557 set_nodelay(sock); 3558 return sock; 3559 } 3560 3561 /* 3562 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains 3563 * the remote channel number. We should do whatever we want, and respond 3564 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. 3565 */ 3566 3567 /* ARGSUSED */ 3568 void 3569 x11_input_open(int type, u_int32_t seq, void *ctxt) 3570 { 3571 Channel *c = NULL; 3572 int remote_id, sock = 0; 3573 char *remote_host; 3574 3575 debug("Received X11 open request."); 3576 3577 remote_id = packet_get_int(); 3578 3579 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 3580 remote_host = packet_get_string(NULL); 3581 } else { 3582 remote_host = xstrdup("unknown (remote did not supply name)"); 3583 } 3584 packet_check_eom(); 3585 3586 /* Obtain a connection to the real X display. */ 3587 sock = x11_connect_display(); 3588 if (sock != -1) { 3589 /* Allocate a channel for this connection. */ 3590 c = channel_new("connected x11 socket", 3591 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, 3592 remote_host, 1); 3593 c->remote_id = remote_id; 3594 c->force_drain = 1; 3595 } 3596 xfree(remote_host); 3597 if (c == NULL) { 3598 /* Send refusal to the remote host. */ 3599 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3600 packet_put_int(remote_id); 3601 } else { 3602 /* Send a confirmation to the remote host. */ 3603 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 3604 packet_put_int(remote_id); 3605 packet_put_int(c->self); 3606 } 3607 packet_send(); 3608 } 3609 3610 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ 3611 /* ARGSUSED */ 3612 void 3613 deny_input_open(int type, u_int32_t seq, void *ctxt) 3614 { 3615 int rchan = packet_get_int(); 3616 3617 switch (type) { 3618 case SSH_SMSG_AGENT_OPEN: 3619 error("Warning: ssh server tried agent forwarding."); 3620 break; 3621 case SSH_SMSG_X11_OPEN: 3622 error("Warning: ssh server tried X11 forwarding."); 3623 break; 3624 default: 3625 error("deny_input_open: type %d", type); 3626 break; 3627 } 3628 error("Warning: this is probably a break-in attempt by a malicious server."); 3629 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3630 packet_put_int(rchan); 3631 packet_send(); 3632 } 3633 3634 /* 3635 * Requests forwarding of X11 connections, generates fake authentication 3636 * data, and enables authentication spoofing. 3637 * This should be called in the client only. 3638 */ 3639 void 3640 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp, 3641 const char *proto, const char *data, int want_reply) 3642 { 3643 u_int data_len = (u_int) strlen(data) / 2; 3644 u_int i, value; 3645 char *new_data; 3646 int screen_number; 3647 const char *cp; 3648 u_int32_t rnd = 0; 3649 3650 if (x11_saved_display == NULL) 3651 x11_saved_display = xstrdup(disp); 3652 else if (strcmp(disp, x11_saved_display) != 0) { 3653 error("x11_request_forwarding_with_spoofing: different " 3654 "$DISPLAY already forwarded"); 3655 return; 3656 } 3657 3658 cp = strchr(disp, ':'); 3659 if (cp) 3660 cp = strchr(cp, '.'); 3661 if (cp) 3662 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 3663 else 3664 screen_number = 0; 3665 3666 if (x11_saved_proto == NULL) { 3667 /* Save protocol name. */ 3668 x11_saved_proto = xstrdup(proto); 3669 /* 3670 * Extract real authentication data and generate fake data 3671 * of the same length. 3672 */ 3673 x11_saved_data = xmalloc(data_len); 3674 x11_fake_data = xmalloc(data_len); 3675 for (i = 0; i < data_len; i++) { 3676 if (sscanf(data + 2 * i, "%2x", &value) != 1) 3677 fatal("x11_request_forwarding: bad " 3678 "authentication data: %.100s", data); 3679 if (i % 4 == 0) 3680 rnd = arc4random(); 3681 x11_saved_data[i] = value; 3682 x11_fake_data[i] = rnd & 0xff; 3683 rnd >>= 8; 3684 } 3685 x11_saved_data_len = data_len; 3686 x11_fake_data_len = data_len; 3687 } 3688 3689 /* Convert the fake data into hex. */ 3690 new_data = tohex(x11_fake_data, data_len); 3691 3692 /* Send the request packet. */ 3693 if (compat20) { 3694 channel_request_start(client_session_id, "x11-req", want_reply); 3695 packet_put_char(0); /* XXX bool single connection */ 3696 } else { 3697 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); 3698 } 3699 packet_put_cstring(proto); 3700 packet_put_cstring(new_data); 3701 packet_put_int(screen_number); 3702 packet_send(); 3703 packet_write_wait(); 3704 xfree(new_data); 3705 } 3706 3707 3708 /* -- agent forwarding */ 3709 3710 /* Sends a message to the server to request authentication fd forwarding. */ 3711 3712 void 3713 auth_request_forwarding(void) 3714 { 3715 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); 3716 packet_send(); 3717 packet_write_wait(); 3718 } 3719