1 /* $OpenBSD: channels.c,v 1.309 2010/08/05 13:08:42 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include "includes.h" 43 44 #include <sys/types.h> 45 #include <sys/ioctl.h> 46 #include <sys/un.h> 47 #include <sys/socket.h> 48 #ifdef HAVE_SYS_TIME_H 49 # include <sys/time.h> 50 #endif 51 52 #include <netinet/in.h> 53 #include <arpa/inet.h> 54 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <netdb.h> 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #include <termios.h> 62 #include <unistd.h> 63 #include <stdarg.h> 64 65 #include "openbsd-compat/sys-queue.h" 66 #include "xmalloc.h" 67 #include "ssh.h" 68 #include "ssh1.h" 69 #include "ssh2.h" 70 #include "packet.h" 71 #include "log.h" 72 #include "misc.h" 73 #include "buffer.h" 74 #include "channels.h" 75 #include "compat.h" 76 #include "canohost.h" 77 #include "key.h" 78 #include "authfd.h" 79 #include "pathnames.h" 80 81 /* -- channel core */ 82 83 /* 84 * Pointer to an array containing all allocated channels. The array is 85 * dynamically extended as needed. 86 */ 87 static Channel **channels = NULL; 88 89 /* 90 * Size of the channel array. All slots of the array must always be 91 * initialized (at least the type field); unused slots set to NULL 92 */ 93 static u_int channels_alloc = 0; 94 95 /* 96 * Maximum file descriptor value used in any of the channels. This is 97 * updated in channel_new. 98 */ 99 static int channel_max_fd = 0; 100 101 102 /* -- tcp forwarding */ 103 104 /* 105 * Data structure for storing which hosts are permitted for forward requests. 106 * The local sides of any remote forwards are stored in this array to prevent 107 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 108 * network (which might be behind a firewall). 109 */ 110 typedef struct { 111 char *host_to_connect; /* Connect to 'host'. */ 112 u_short port_to_connect; /* Connect to 'port'. */ 113 u_short listen_port; /* Remote side should listen port number. */ 114 } ForwardPermission; 115 116 /* List of all permitted host/port pairs to connect by the user. */ 117 static ForwardPermission *permitted_opens = NULL; 118 119 /* List of all permitted host/port pairs to connect by the admin. */ 120 static ForwardPermission *permitted_adm_opens = NULL; 121 122 /* Number of permitted host/port pairs in the array permitted by the user. */ 123 static int num_permitted_opens = 0; 124 125 /* Number of permitted host/port pair in the array permitted by the admin. */ 126 static int num_adm_permitted_opens = 0; 127 128 /* 129 * If this is true, all opens are permitted. This is the case on the server 130 * on which we have to trust the client anyway, and the user could do 131 * anything after logging in anyway. 132 */ 133 static int all_opens_permitted = 0; 134 135 136 /* -- X11 forwarding */ 137 138 /* Maximum number of fake X11 displays to try. */ 139 #define MAX_DISPLAYS 1000 140 141 /* Saved X11 local (client) display. */ 142 static char *x11_saved_display = NULL; 143 144 /* Saved X11 authentication protocol name. */ 145 static char *x11_saved_proto = NULL; 146 147 /* Saved X11 authentication data. This is the real data. */ 148 static char *x11_saved_data = NULL; 149 static u_int x11_saved_data_len = 0; 150 151 /* 152 * Fake X11 authentication data. This is what the server will be sending us; 153 * we should replace any occurrences of this by the real data. 154 */ 155 static u_char *x11_fake_data = NULL; 156 static u_int x11_fake_data_len; 157 158 159 /* -- agent forwarding */ 160 161 #define NUM_SOCKS 10 162 163 /* AF_UNSPEC or AF_INET or AF_INET6 */ 164 static int IPv4or6 = AF_UNSPEC; 165 166 /* helper */ 167 static void port_open_helper(Channel *c, char *rtype); 168 169 /* non-blocking connect helpers */ 170 static int connect_next(struct channel_connect *); 171 static void channel_connect_ctx_free(struct channel_connect *); 172 173 174 static int hpn_disabled = 0; 175 static int hpn_buffer_size = 2 * 1024 * 1024; 176 177 /* -- channel core */ 178 179 180 181 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->local_window = window; 319 c->local_window_max = window; 320 c->local_consumed = 0; 321 c->local_maxpacket = maxpack; 322 c->dynamic_window = 0; 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 debug3("channel %d: close_fds r %d w %d e %d", 384 c->self, c->rfd, c->wfd, c->efd); 385 386 channel_close_fd(&c->sock); 387 channel_close_fd(&c->rfd); 388 channel_close_fd(&c->wfd); 389 channel_close_fd(&c->efd); 390 } 391 392 /* Free the channel and close its fd/socket. */ 393 void 394 channel_free(Channel *c) 395 { 396 char *s; 397 u_int i, n; 398 struct channel_confirm *cc; 399 400 for (n = 0, i = 0; i < channels_alloc; i++) 401 if (channels[i]) 402 n++; 403 debug("channel %d: free: %s, nchannels %u", c->self, 404 c->remote_name ? c->remote_name : "???", n); 405 406 s = channel_open_message(); 407 debug3("channel %d: status: %s", c->self, s); 408 xfree(s); 409 410 if (c->sock != -1) 411 shutdown(c->sock, SHUT_RDWR); 412 channel_close_fds(c); 413 buffer_free(&c->input); 414 buffer_free(&c->output); 415 buffer_free(&c->extended); 416 if (c->remote_name) { 417 xfree(c->remote_name); 418 c->remote_name = NULL; 419 } 420 if (c->path) { 421 xfree(c->path); 422 c->path = NULL; 423 } 424 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 425 if (cc->abandon_cb != NULL) 426 cc->abandon_cb(c, cc->ctx); 427 TAILQ_REMOVE(&c->status_confirms, cc, entry); 428 bzero(cc, sizeof(*cc)); 429 xfree(cc); 430 } 431 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 432 c->filter_cleanup(c->self, c->filter_ctx); 433 channels[c->self] = NULL; 434 xfree(c); 435 } 436 437 void 438 channel_free_all(void) 439 { 440 u_int i; 441 442 for (i = 0; i < channels_alloc; i++) 443 if (channels[i] != NULL) 444 channel_free(channels[i]); 445 } 446 447 /* 448 * Closes the sockets/fds of all channels. This is used to close extra file 449 * descriptors after a fork. 450 */ 451 void 452 channel_close_all(void) 453 { 454 u_int i; 455 456 for (i = 0; i < channels_alloc; i++) 457 if (channels[i] != NULL) 458 channel_close_fds(channels[i]); 459 } 460 461 /* 462 * Stop listening to channels. 463 */ 464 void 465 channel_stop_listening(void) 466 { 467 u_int i; 468 Channel *c; 469 470 for (i = 0; i < channels_alloc; i++) { 471 c = channels[i]; 472 if (c != NULL) { 473 switch (c->type) { 474 case SSH_CHANNEL_AUTH_SOCKET: 475 case SSH_CHANNEL_PORT_LISTENER: 476 case SSH_CHANNEL_RPORT_LISTENER: 477 case SSH_CHANNEL_X11_LISTENER: 478 channel_close_fd(&c->sock); 479 channel_free(c); 480 break; 481 } 482 } 483 } 484 } 485 486 /* 487 * Returns true if no channel has too much buffered data, and false if one or 488 * more channel is overfull. 489 */ 490 int 491 channel_not_very_much_buffered_data(void) 492 { 493 u_int i; 494 Channel *c; 495 496 for (i = 0; i < channels_alloc; i++) { 497 c = channels[i]; 498 if (c != NULL && c->type == SSH_CHANNEL_OPEN) { 499 #if 0 500 if (!compat20 && 501 buffer_len(&c->input) > packet_get_maxsize()) { 502 debug2("channel %d: big input buffer %d", 503 c->self, buffer_len(&c->input)); 504 return 0; 505 } 506 #endif 507 if (buffer_len(&c->output) > packet_get_maxsize()) { 508 debug2("channel %d: big output buffer %u > %u", 509 c->self, buffer_len(&c->output), 510 packet_get_maxsize()); 511 return 0; 512 } 513 } 514 } 515 return 1; 516 } 517 518 /* Returns true if any channel is still open. */ 519 int 520 channel_still_open(void) 521 { 522 u_int i; 523 Channel *c; 524 525 for (i = 0; i < channels_alloc; i++) { 526 c = channels[i]; 527 if (c == NULL) 528 continue; 529 switch (c->type) { 530 case SSH_CHANNEL_X11_LISTENER: 531 case SSH_CHANNEL_PORT_LISTENER: 532 case SSH_CHANNEL_RPORT_LISTENER: 533 case SSH_CHANNEL_MUX_LISTENER: 534 case SSH_CHANNEL_CLOSED: 535 case SSH_CHANNEL_AUTH_SOCKET: 536 case SSH_CHANNEL_DYNAMIC: 537 case SSH_CHANNEL_CONNECTING: 538 case SSH_CHANNEL_ZOMBIE: 539 continue; 540 case SSH_CHANNEL_LARVAL: 541 if (!compat20) 542 fatal("cannot happen: SSH_CHANNEL_LARVAL"); 543 continue; 544 case SSH_CHANNEL_OPENING: 545 case SSH_CHANNEL_OPEN: 546 case SSH_CHANNEL_X11_OPEN: 547 case SSH_CHANNEL_MUX_CLIENT: 548 return 1; 549 case SSH_CHANNEL_INPUT_DRAINING: 550 case SSH_CHANNEL_OUTPUT_DRAINING: 551 if (!compat13) 552 fatal("cannot happen: OUT_DRAIN"); 553 return 1; 554 default: 555 fatal("channel_still_open: bad channel type %d", c->type); 556 /* NOTREACHED */ 557 } 558 } 559 return 0; 560 } 561 562 /* Returns the id of an open channel suitable for keepaliving */ 563 int 564 channel_find_open(void) 565 { 566 u_int i; 567 Channel *c; 568 569 for (i = 0; i < channels_alloc; i++) { 570 c = channels[i]; 571 if (c == NULL || c->remote_id < 0) 572 continue; 573 switch (c->type) { 574 case SSH_CHANNEL_CLOSED: 575 case SSH_CHANNEL_DYNAMIC: 576 case SSH_CHANNEL_X11_LISTENER: 577 case SSH_CHANNEL_PORT_LISTENER: 578 case SSH_CHANNEL_RPORT_LISTENER: 579 case SSH_CHANNEL_MUX_LISTENER: 580 case SSH_CHANNEL_MUX_CLIENT: 581 case SSH_CHANNEL_OPENING: 582 case SSH_CHANNEL_CONNECTING: 583 case SSH_CHANNEL_ZOMBIE: 584 continue; 585 case SSH_CHANNEL_LARVAL: 586 case SSH_CHANNEL_AUTH_SOCKET: 587 case SSH_CHANNEL_OPEN: 588 case SSH_CHANNEL_X11_OPEN: 589 return i; 590 case SSH_CHANNEL_INPUT_DRAINING: 591 case SSH_CHANNEL_OUTPUT_DRAINING: 592 if (!compat13) 593 fatal("cannot happen: OUT_DRAIN"); 594 return i; 595 default: 596 fatal("channel_find_open: bad channel type %d", c->type); 597 /* NOTREACHED */ 598 } 599 } 600 return -1; 601 } 602 603 604 /* 605 * Returns a message describing the currently open forwarded connections, 606 * suitable for sending to the client. The message contains crlf pairs for 607 * newlines. 608 */ 609 char * 610 channel_open_message(void) 611 { 612 Buffer buffer; 613 Channel *c; 614 char buf[1024], *cp; 615 u_int i; 616 617 buffer_init(&buffer); 618 snprintf(buf, sizeof buf, "The following connections are open:\r\n"); 619 buffer_append(&buffer, buf, strlen(buf)); 620 for (i = 0; i < channels_alloc; i++) { 621 c = channels[i]; 622 if (c == NULL) 623 continue; 624 switch (c->type) { 625 case SSH_CHANNEL_X11_LISTENER: 626 case SSH_CHANNEL_PORT_LISTENER: 627 case SSH_CHANNEL_RPORT_LISTENER: 628 case SSH_CHANNEL_CLOSED: 629 case SSH_CHANNEL_AUTH_SOCKET: 630 case SSH_CHANNEL_ZOMBIE: 631 case SSH_CHANNEL_MUX_CLIENT: 632 case SSH_CHANNEL_MUX_LISTENER: 633 continue; 634 case SSH_CHANNEL_LARVAL: 635 case SSH_CHANNEL_OPENING: 636 case SSH_CHANNEL_CONNECTING: 637 case SSH_CHANNEL_DYNAMIC: 638 case SSH_CHANNEL_OPEN: 639 case SSH_CHANNEL_X11_OPEN: 640 case SSH_CHANNEL_INPUT_DRAINING: 641 case SSH_CHANNEL_OUTPUT_DRAINING: 642 snprintf(buf, sizeof buf, 643 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n", 644 c->self, c->remote_name, 645 c->type, c->remote_id, 646 c->istate, buffer_len(&c->input), 647 c->ostate, buffer_len(&c->output), 648 c->rfd, c->wfd, c->ctl_chan); 649 buffer_append(&buffer, buf, strlen(buf)); 650 continue; 651 default: 652 fatal("channel_open_message: bad channel type %d", c->type); 653 /* NOTREACHED */ 654 } 655 } 656 buffer_append(&buffer, "\0", 1); 657 cp = xstrdup(buffer_ptr(&buffer)); 658 buffer_free(&buffer); 659 return cp; 660 } 661 662 void 663 channel_send_open(int id) 664 { 665 Channel *c = channel_lookup(id); 666 667 if (c == NULL) { 668 logit("channel_send_open: %d: bad id", id); 669 return; 670 } 671 debug2("channel %d: send open", id); 672 packet_start(SSH2_MSG_CHANNEL_OPEN); 673 packet_put_cstring(c->ctype); 674 packet_put_int(c->self); 675 packet_put_int(c->local_window); 676 packet_put_int(c->local_maxpacket); 677 packet_send(); 678 } 679 680 void 681 channel_request_start(int id, char *service, int wantconfirm) 682 { 683 Channel *c = channel_lookup(id); 684 685 if (c == NULL) { 686 logit("channel_request_start: %d: unknown channel id", id); 687 return; 688 } 689 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 690 packet_start(SSH2_MSG_CHANNEL_REQUEST); 691 packet_put_int(c->remote_id); 692 packet_put_cstring(service); 693 packet_put_char(wantconfirm); 694 } 695 696 void 697 channel_register_status_confirm(int id, channel_confirm_cb *cb, 698 channel_confirm_abandon_cb *abandon_cb, void *ctx) 699 { 700 struct channel_confirm *cc; 701 Channel *c; 702 703 if ((c = channel_lookup(id)) == NULL) 704 fatal("channel_register_expect: %d: bad id", id); 705 706 cc = xmalloc(sizeof(*cc)); 707 cc->cb = cb; 708 cc->abandon_cb = abandon_cb; 709 cc->ctx = ctx; 710 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 711 } 712 713 void 714 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx) 715 { 716 Channel *c = channel_lookup(id); 717 718 if (c == NULL) { 719 logit("channel_register_open_confirm: %d: bad id", id); 720 return; 721 } 722 c->open_confirm = fn; 723 c->open_confirm_ctx = ctx; 724 } 725 726 void 727 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close) 728 { 729 Channel *c = channel_by_id(id); 730 731 if (c == NULL) { 732 logit("channel_register_cleanup: %d: bad id", id); 733 return; 734 } 735 c->detach_user = fn; 736 c->detach_close = do_close; 737 } 738 739 void 740 channel_cancel_cleanup(int id) 741 { 742 Channel *c = channel_by_id(id); 743 744 if (c == NULL) { 745 logit("channel_cancel_cleanup: %d: bad id", id); 746 return; 747 } 748 c->detach_user = NULL; 749 c->detach_close = 0; 750 } 751 752 void 753 channel_register_filter(int id, channel_infilter_fn *ifn, 754 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 755 { 756 Channel *c = channel_lookup(id); 757 758 if (c == NULL) { 759 logit("channel_register_filter: %d: bad id", id); 760 return; 761 } 762 c->input_filter = ifn; 763 c->output_filter = ofn; 764 c->filter_ctx = ctx; 765 c->filter_cleanup = cfn; 766 } 767 768 void 769 channel_set_fds(int id, int rfd, int wfd, int efd, 770 int extusage, int nonblock, int is_tty, u_int window_max) 771 { 772 Channel *c = channel_lookup(id); 773 774 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 775 fatal("channel_activate for non-larval channel %d.", id); 776 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty); 777 c->type = SSH_CHANNEL_OPEN; 778 c->local_window = c->local_window_max = window_max; 779 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 780 packet_put_int(c->remote_id); 781 packet_put_int(c->local_window); 782 packet_send(); 783 } 784 785 /* 786 * 'channel_pre*' are called just before select() to add any bits relevant to 787 * channels in the select bitmasks. 788 */ 789 /* 790 * 'channel_post*': perform any appropriate operations for channels which 791 * have events pending. 792 */ 793 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset); 794 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; 795 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; 796 797 /* ARGSUSED */ 798 static void 799 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset) 800 { 801 FD_SET(c->sock, readset); 802 } 803 804 /* ARGSUSED */ 805 static void 806 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset) 807 { 808 debug3("channel %d: waiting for connection", c->self); 809 FD_SET(c->sock, writeset); 810 } 811 812 static void 813 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset) 814 { 815 if (buffer_len(&c->input) < packet_get_maxsize()) 816 FD_SET(c->sock, readset); 817 if (buffer_len(&c->output) > 0) 818 FD_SET(c->sock, writeset); 819 } 820 821 int channel_tcpwinsz () { 822 u_int32_t tcpwinsz = 0; 823 socklen_t optsz = sizeof(tcpwinsz); 824 int ret = -1; 825 826 /* if we aren't on a socket return 128KB*/ 827 if(!packet_connection_is_on_socket()) 828 return(128*1024); 829 ret = getsockopt(packet_get_connection_in(), 830 SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz); 831 /* return no more than 64MB */ 832 if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN) 833 tcpwinsz = BUFFER_MAX_LEN_HPN; 834 debug2("tcpwinsz: %d for connection: %d", tcpwinsz, 835 packet_get_connection_in()); 836 return(tcpwinsz); 837 } 838 839 static void 840 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset) 841 { 842 u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); 843 844 /* check buffer limits */ 845 if ((!c->tcpwinsz) || (c->dynamic_window > 0)) 846 c->tcpwinsz = channel_tcpwinsz(); 847 848 limit = MIN(limit, 2 * c->tcpwinsz); 849 850 if (c->istate == CHAN_INPUT_OPEN && 851 limit > 0 && 852 buffer_len(&c->input) < limit && 853 buffer_check_alloc(&c->input, CHAN_RBUF)) 854 FD_SET(c->rfd, readset); 855 if (c->ostate == CHAN_OUTPUT_OPEN || 856 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 857 if (buffer_len(&c->output) > 0) { 858 FD_SET(c->wfd, writeset); 859 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 860 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 861 debug2("channel %d: obuf_empty delayed efd %d/(%d)", 862 c->self, c->efd, buffer_len(&c->extended)); 863 else 864 chan_obuf_empty(c); 865 } 866 } 867 /** XXX check close conditions, too */ 868 if (compat20 && c->efd != -1 && 869 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) { 870 if (c->extended_usage == CHAN_EXTENDED_WRITE && 871 buffer_len(&c->extended) > 0) 872 FD_SET(c->efd, writeset); 873 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 874 (c->extended_usage == CHAN_EXTENDED_READ || 875 c->extended_usage == CHAN_EXTENDED_IGNORE) && 876 buffer_len(&c->extended) < c->remote_window) 877 FD_SET(c->efd, readset); 878 } 879 /* XXX: What about efd? races? */ 880 } 881 882 /* ARGSUSED */ 883 static void 884 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset) 885 { 886 if (buffer_len(&c->input) == 0) { 887 packet_start(SSH_MSG_CHANNEL_CLOSE); 888 packet_put_int(c->remote_id); 889 packet_send(); 890 c->type = SSH_CHANNEL_CLOSED; 891 debug2("channel %d: closing after input drain.", c->self); 892 } 893 } 894 895 /* ARGSUSED */ 896 static void 897 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset) 898 { 899 if (buffer_len(&c->output) == 0) 900 chan_mark_dead(c); 901 else 902 FD_SET(c->sock, writeset); 903 } 904 905 /* 906 * This is a special state for X11 authentication spoofing. An opened X11 907 * connection (when authentication spoofing is being done) remains in this 908 * state until the first packet has been completely read. The authentication 909 * data in that packet is then substituted by the real data if it matches the 910 * fake data, and the channel is put into normal mode. 911 * XXX All this happens at the client side. 912 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 913 */ 914 static int 915 x11_open_helper(Buffer *b) 916 { 917 u_char *ucp; 918 u_int proto_len, data_len; 919 920 /* Check if the fixed size part of the packet is in buffer. */ 921 if (buffer_len(b) < 12) 922 return 0; 923 924 /* Parse the lengths of variable-length fields. */ 925 ucp = buffer_ptr(b); 926 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 927 proto_len = 256 * ucp[6] + ucp[7]; 928 data_len = 256 * ucp[8] + ucp[9]; 929 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 930 proto_len = ucp[6] + 256 * ucp[7]; 931 data_len = ucp[8] + 256 * ucp[9]; 932 } else { 933 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 934 ucp[0]); 935 return -1; 936 } 937 938 /* Check if the whole packet is in buffer. */ 939 if (buffer_len(b) < 940 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 941 return 0; 942 943 /* Check if authentication protocol matches. */ 944 if (proto_len != strlen(x11_saved_proto) || 945 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { 946 debug2("X11 connection uses different authentication protocol."); 947 return -1; 948 } 949 /* Check if authentication data matches our fake data. */ 950 if (data_len != x11_fake_data_len || 951 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 952 x11_fake_data, x11_fake_data_len) != 0) { 953 debug2("X11 auth data does not match fake data."); 954 return -1; 955 } 956 /* Check fake data length */ 957 if (x11_fake_data_len != x11_saved_data_len) { 958 error("X11 fake_data_len %d != saved_data_len %d", 959 x11_fake_data_len, x11_saved_data_len); 960 return -1; 961 } 962 /* 963 * Received authentication protocol and data match 964 * our fake data. Substitute the fake data with real 965 * data. 966 */ 967 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 968 x11_saved_data, x11_saved_data_len); 969 return 1; 970 } 971 972 static void 973 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset) 974 { 975 int ret = x11_open_helper(&c->output); 976 977 if (ret == 1) { 978 /* Start normal processing for the channel. */ 979 c->type = SSH_CHANNEL_OPEN; 980 channel_pre_open_13(c, readset, writeset); 981 } else if (ret == -1) { 982 /* 983 * We have received an X11 connection that has bad 984 * authentication information. 985 */ 986 logit("X11 connection rejected because of wrong authentication."); 987 buffer_clear(&c->input); 988 buffer_clear(&c->output); 989 channel_close_fd(&c->sock); 990 c->sock = -1; 991 c->type = SSH_CHANNEL_CLOSED; 992 packet_start(SSH_MSG_CHANNEL_CLOSE); 993 packet_put_int(c->remote_id); 994 packet_send(); 995 } 996 } 997 998 static void 999 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset) 1000 { 1001 int ret = x11_open_helper(&c->output); 1002 1003 /* c->force_drain = 1; */ 1004 1005 if (ret == 1) { 1006 c->type = SSH_CHANNEL_OPEN; 1007 channel_pre_open(c, readset, writeset); 1008 } else if (ret == -1) { 1009 logit("X11 connection rejected because of wrong authentication."); 1010 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); 1011 chan_read_failed(c); 1012 buffer_clear(&c->input); 1013 chan_ibuf_empty(c); 1014 buffer_clear(&c->output); 1015 /* for proto v1, the peer will send an IEOF */ 1016 if (compat20) 1017 chan_write_failed(c); 1018 else 1019 c->type = SSH_CHANNEL_OPEN; 1020 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1021 } 1022 } 1023 1024 static void 1025 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1026 { 1027 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1028 buffer_check_alloc(&c->input, CHAN_RBUF)) 1029 FD_SET(c->rfd, readset); 1030 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1031 /* clear buffer immediately (discard any partial packet) */ 1032 buffer_clear(&c->input); 1033 chan_ibuf_empty(c); 1034 /* Start output drain. XXX just kill chan? */ 1035 chan_rcvd_oclose(c); 1036 } 1037 if (c->ostate == CHAN_OUTPUT_OPEN || 1038 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1039 if (buffer_len(&c->output) > 0) 1040 FD_SET(c->wfd, writeset); 1041 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1042 chan_obuf_empty(c); 1043 } 1044 } 1045 1046 /* try to decode a socks4 header */ 1047 /* ARGSUSED */ 1048 static int 1049 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset) 1050 { 1051 char *p, *host; 1052 u_int len, have, i, found, need; 1053 char username[256]; 1054 struct { 1055 u_int8_t version; 1056 u_int8_t command; 1057 u_int16_t dest_port; 1058 struct in_addr dest_addr; 1059 } s4_req, s4_rsp; 1060 1061 debug2("channel %d: decode socks4", c->self); 1062 1063 have = buffer_len(&c->input); 1064 len = sizeof(s4_req); 1065 if (have < len) 1066 return 0; 1067 p = buffer_ptr(&c->input); 1068 1069 need = 1; 1070 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1071 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1072 debug2("channel %d: socks4a request", c->self); 1073 /* ... and needs an extra string (the hostname) */ 1074 need = 2; 1075 } 1076 /* Check for terminating NUL on the string(s) */ 1077 for (found = 0, i = len; i < have; i++) { 1078 if (p[i] == '\0') { 1079 found++; 1080 if (found == need) 1081 break; 1082 } 1083 if (i > 1024) { 1084 /* the peer is probably sending garbage */ 1085 debug("channel %d: decode socks4: too long", 1086 c->self); 1087 return -1; 1088 } 1089 } 1090 if (found < need) 1091 return 0; 1092 buffer_get(&c->input, (char *)&s4_req.version, 1); 1093 buffer_get(&c->input, (char *)&s4_req.command, 1); 1094 buffer_get(&c->input, (char *)&s4_req.dest_port, 2); 1095 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); 1096 have = buffer_len(&c->input); 1097 p = buffer_ptr(&c->input); 1098 len = strlen(p); 1099 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1100 len++; /* trailing '\0' */ 1101 if (len > have) 1102 fatal("channel %d: decode socks4: len %d > have %d", 1103 c->self, len, have); 1104 strlcpy(username, p, sizeof(username)); 1105 buffer_consume(&c->input, len); 1106 1107 if (c->path != NULL) { 1108 xfree(c->path); 1109 c->path = NULL; 1110 } 1111 if (need == 1) { /* SOCKS4: one string */ 1112 host = inet_ntoa(s4_req.dest_addr); 1113 c->path = xstrdup(host); 1114 } else { /* SOCKS4A: two strings */ 1115 have = buffer_len(&c->input); 1116 p = buffer_ptr(&c->input); 1117 len = strlen(p); 1118 debug2("channel %d: decode socks4a: host %s/%d", 1119 c->self, p, len); 1120 len++; /* trailing '\0' */ 1121 if (len > have) 1122 fatal("channel %d: decode socks4a: len %d > have %d", 1123 c->self, len, have); 1124 if (len > NI_MAXHOST) { 1125 error("channel %d: hostname \"%.100s\" too long", 1126 c->self, p); 1127 return -1; 1128 } 1129 c->path = xstrdup(p); 1130 buffer_consume(&c->input, len); 1131 } 1132 c->host_port = ntohs(s4_req.dest_port); 1133 1134 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1135 c->self, c->path, c->host_port, s4_req.command); 1136 1137 if (s4_req.command != 1) { 1138 debug("channel %d: cannot handle: %s cn %d", 1139 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1140 return -1; 1141 } 1142 s4_rsp.version = 0; /* vn: 0 for reply */ 1143 s4_rsp.command = 90; /* cd: req granted */ 1144 s4_rsp.dest_port = 0; /* ignored */ 1145 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1146 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp)); 1147 return 1; 1148 } 1149 1150 /* try to decode a socks5 header */ 1151 #define SSH_SOCKS5_AUTHDONE 0x1000 1152 #define SSH_SOCKS5_NOAUTH 0x00 1153 #define SSH_SOCKS5_IPV4 0x01 1154 #define SSH_SOCKS5_DOMAIN 0x03 1155 #define SSH_SOCKS5_IPV6 0x04 1156 #define SSH_SOCKS5_CONNECT 0x01 1157 #define SSH_SOCKS5_SUCCESS 0x00 1158 1159 /* ARGSUSED */ 1160 static int 1161 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset) 1162 { 1163 struct { 1164 u_int8_t version; 1165 u_int8_t command; 1166 u_int8_t reserved; 1167 u_int8_t atyp; 1168 } s5_req, s5_rsp; 1169 u_int16_t dest_port; 1170 u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1171 u_int have, need, i, found, nmethods, addrlen, af; 1172 1173 debug2("channel %d: decode socks5", c->self); 1174 p = buffer_ptr(&c->input); 1175 if (p[0] != 0x05) 1176 return -1; 1177 have = buffer_len(&c->input); 1178 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1179 /* format: ver | nmethods | methods */ 1180 if (have < 2) 1181 return 0; 1182 nmethods = p[1]; 1183 if (have < nmethods + 2) 1184 return 0; 1185 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1186 for (found = 0, i = 2; i < nmethods + 2; i++) { 1187 if (p[i] == SSH_SOCKS5_NOAUTH) { 1188 found = 1; 1189 break; 1190 } 1191 } 1192 if (!found) { 1193 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1194 c->self); 1195 return -1; 1196 } 1197 buffer_consume(&c->input, nmethods + 2); 1198 buffer_put_char(&c->output, 0x05); /* version */ 1199 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ 1200 FD_SET(c->sock, writeset); 1201 c->flags |= SSH_SOCKS5_AUTHDONE; 1202 debug2("channel %d: socks5 auth done", c->self); 1203 return 0; /* need more */ 1204 } 1205 debug2("channel %d: socks5 post auth", c->self); 1206 if (have < sizeof(s5_req)+1) 1207 return 0; /* need more */ 1208 memcpy(&s5_req, p, sizeof(s5_req)); 1209 if (s5_req.version != 0x05 || 1210 s5_req.command != SSH_SOCKS5_CONNECT || 1211 s5_req.reserved != 0x00) { 1212 debug2("channel %d: only socks5 connect supported", c->self); 1213 return -1; 1214 } 1215 switch (s5_req.atyp){ 1216 case SSH_SOCKS5_IPV4: 1217 addrlen = 4; 1218 af = AF_INET; 1219 break; 1220 case SSH_SOCKS5_DOMAIN: 1221 addrlen = p[sizeof(s5_req)]; 1222 af = -1; 1223 break; 1224 case SSH_SOCKS5_IPV6: 1225 addrlen = 16; 1226 af = AF_INET6; 1227 break; 1228 default: 1229 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1230 return -1; 1231 } 1232 need = sizeof(s5_req) + addrlen + 2; 1233 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1234 need++; 1235 if (have < need) 1236 return 0; 1237 buffer_consume(&c->input, sizeof(s5_req)); 1238 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1239 buffer_consume(&c->input, 1); /* host string length */ 1240 buffer_get(&c->input, (char *)&dest_addr, addrlen); 1241 buffer_get(&c->input, (char *)&dest_port, 2); 1242 dest_addr[addrlen] = '\0'; 1243 if (c->path != NULL) { 1244 xfree(c->path); 1245 c->path = NULL; 1246 } 1247 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1248 if (addrlen >= NI_MAXHOST) { 1249 error("channel %d: dynamic request: socks5 hostname " 1250 "\"%.100s\" too long", c->self, dest_addr); 1251 return -1; 1252 } 1253 c->path = xstrdup(dest_addr); 1254 } else { 1255 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1256 return -1; 1257 c->path = xstrdup(ntop); 1258 } 1259 c->host_port = ntohs(dest_port); 1260 1261 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1262 c->self, c->path, c->host_port, s5_req.command); 1263 1264 s5_rsp.version = 0x05; 1265 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1266 s5_rsp.reserved = 0; /* ignored */ 1267 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1268 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY; 1269 dest_port = 0; /* ignored */ 1270 1271 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp)); 1272 buffer_append(&c->output, &dest_addr, sizeof(struct in_addr)); 1273 buffer_append(&c->output, &dest_port, sizeof(dest_port)); 1274 return 1; 1275 } 1276 1277 Channel * 1278 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect, 1279 int in, int out) 1280 { 1281 Channel *c; 1282 1283 debug("channel_connect_stdio_fwd %s:%d", host_to_connect, 1284 port_to_connect); 1285 1286 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out, 1287 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1288 0, "stdio-forward", /*nonblock*/0); 1289 1290 c->path = xstrdup(host_to_connect); 1291 c->host_port = port_to_connect; 1292 c->listening_port = 0; 1293 c->force_drain = 1; 1294 1295 channel_register_fds(c, in, out, -1, 0, 1, 0); 1296 port_open_helper(c, "direct-tcpip"); 1297 1298 return c; 1299 } 1300 1301 /* dynamic port forwarding */ 1302 static void 1303 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset) 1304 { 1305 u_char *p; 1306 u_int have; 1307 int ret; 1308 1309 have = buffer_len(&c->input); 1310 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1311 /* buffer_dump(&c->input); */ 1312 /* check if the fixed size part of the packet is in buffer. */ 1313 if (have < 3) { 1314 /* need more */ 1315 FD_SET(c->sock, readset); 1316 return; 1317 } 1318 /* try to guess the protocol */ 1319 p = buffer_ptr(&c->input); 1320 switch (p[0]) { 1321 case 0x04: 1322 ret = channel_decode_socks4(c, readset, writeset); 1323 break; 1324 case 0x05: 1325 ret = channel_decode_socks5(c, readset, writeset); 1326 break; 1327 default: 1328 ret = -1; 1329 break; 1330 } 1331 if (ret < 0) { 1332 chan_mark_dead(c); 1333 } else if (ret == 0) { 1334 debug2("channel %d: pre_dynamic: need more", c->self); 1335 /* need more */ 1336 FD_SET(c->sock, readset); 1337 } else { 1338 /* switch to the next state */ 1339 c->type = SSH_CHANNEL_OPENING; 1340 port_open_helper(c, "direct-tcpip"); 1341 } 1342 } 1343 1344 /* This is our fake X11 server socket. */ 1345 /* ARGSUSED */ 1346 static void 1347 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset) 1348 { 1349 Channel *nc; 1350 struct sockaddr_storage addr; 1351 int newsock; 1352 socklen_t addrlen; 1353 char buf[16384], *remote_ipaddr; 1354 int remote_port; 1355 1356 if (FD_ISSET(c->sock, readset)) { 1357 debug("X11 connection requested."); 1358 addrlen = sizeof(addr); 1359 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1360 if (c->single_connection) { 1361 debug2("single_connection: closing X11 listener."); 1362 channel_close_fd(&c->sock); 1363 chan_mark_dead(c); 1364 } 1365 if (newsock < 0) { 1366 error("accept: %.100s", strerror(errno)); 1367 return; 1368 } 1369 set_nodelay(newsock); 1370 remote_ipaddr = get_peer_ipaddr(newsock); 1371 remote_port = get_peer_port(newsock); 1372 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1373 remote_ipaddr, remote_port); 1374 1375 nc = channel_new("accepted x11 socket", 1376 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1377 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1378 if (compat20) { 1379 packet_start(SSH2_MSG_CHANNEL_OPEN); 1380 packet_put_cstring("x11"); 1381 packet_put_int(nc->self); 1382 packet_put_int(nc->local_window_max); 1383 packet_put_int(nc->local_maxpacket); 1384 /* originator ipaddr and port */ 1385 packet_put_cstring(remote_ipaddr); 1386 if (datafellows & SSH_BUG_X11FWD) { 1387 debug2("ssh2 x11 bug compat mode"); 1388 } else { 1389 packet_put_int(remote_port); 1390 } 1391 packet_send(); 1392 } else { 1393 packet_start(SSH_SMSG_X11_OPEN); 1394 packet_put_int(nc->self); 1395 if (packet_get_protocol_flags() & 1396 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1397 packet_put_cstring(buf); 1398 packet_send(); 1399 } 1400 xfree(remote_ipaddr); 1401 } 1402 } 1403 1404 static void 1405 port_open_helper(Channel *c, char *rtype) 1406 { 1407 int direct; 1408 char buf[1024]; 1409 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1410 int remote_port = get_peer_port(c->sock); 1411 1412 if (remote_port == -1) { 1413 /* Fake addr/port to appease peers that validate it (Tectia) */ 1414 xfree(remote_ipaddr); 1415 remote_ipaddr = xstrdup("127.0.0.1"); 1416 remote_port = 65535; 1417 } 1418 1419 direct = (strcmp(rtype, "direct-tcpip") == 0); 1420 1421 snprintf(buf, sizeof buf, 1422 "%s: listening port %d for %.100s port %d, " 1423 "connect from %.200s port %d", 1424 rtype, c->listening_port, c->path, c->host_port, 1425 remote_ipaddr, remote_port); 1426 1427 xfree(c->remote_name); 1428 c->remote_name = xstrdup(buf); 1429 1430 if (compat20) { 1431 packet_start(SSH2_MSG_CHANNEL_OPEN); 1432 packet_put_cstring(rtype); 1433 packet_put_int(c->self); 1434 packet_put_int(c->local_window_max); 1435 packet_put_int(c->local_maxpacket); 1436 if (direct) { 1437 /* target host, port */ 1438 packet_put_cstring(c->path); 1439 packet_put_int(c->host_port); 1440 } else { 1441 /* listen address, port */ 1442 packet_put_cstring(c->path); 1443 packet_put_int(c->listening_port); 1444 } 1445 /* originator host and port */ 1446 packet_put_cstring(remote_ipaddr); 1447 packet_put_int((u_int)remote_port); 1448 packet_send(); 1449 } else { 1450 packet_start(SSH_MSG_PORT_OPEN); 1451 packet_put_int(c->self); 1452 packet_put_cstring(c->path); 1453 packet_put_int(c->host_port); 1454 if (packet_get_protocol_flags() & 1455 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1456 packet_put_cstring(c->remote_name); 1457 packet_send(); 1458 } 1459 xfree(remote_ipaddr); 1460 } 1461 1462 static void 1463 channel_set_reuseaddr(int fd) 1464 { 1465 int on = 1; 1466 1467 /* 1468 * Set socket options. 1469 * Allow local port reuse in TIME_WAIT. 1470 */ 1471 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) 1472 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); 1473 } 1474 1475 /* 1476 * This socket is listening for connections to a forwarded TCP/IP port. 1477 */ 1478 /* ARGSUSED */ 1479 static void 1480 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset) 1481 { 1482 Channel *nc; 1483 struct sockaddr_storage addr; 1484 int newsock, nextstate; 1485 socklen_t addrlen; 1486 char *rtype; 1487 1488 if (FD_ISSET(c->sock, readset)) { 1489 debug("Connection to port %d forwarding " 1490 "to %.100s port %d requested.", 1491 c->listening_port, c->path, c->host_port); 1492 1493 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1494 nextstate = SSH_CHANNEL_OPENING; 1495 rtype = "forwarded-tcpip"; 1496 } else { 1497 if (c->host_port == 0) { 1498 nextstate = SSH_CHANNEL_DYNAMIC; 1499 rtype = "dynamic-tcpip"; 1500 } else { 1501 nextstate = SSH_CHANNEL_OPENING; 1502 rtype = "direct-tcpip"; 1503 } 1504 } 1505 1506 addrlen = sizeof(addr); 1507 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1508 if (newsock < 0) { 1509 error("accept: %.100s", strerror(errno)); 1510 return; 1511 } 1512 set_nodelay(newsock); 1513 nc = channel_new(rtype, nextstate, newsock, newsock, -1, 1514 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1515 nc->listening_port = c->listening_port; 1516 nc->host_port = c->host_port; 1517 if (c->path != NULL) 1518 nc->path = xstrdup(c->path); 1519 1520 if (nextstate != SSH_CHANNEL_DYNAMIC) 1521 port_open_helper(nc, rtype); 1522 } 1523 } 1524 1525 /* 1526 * This is the authentication agent socket listening for connections from 1527 * clients. 1528 */ 1529 /* ARGSUSED */ 1530 static void 1531 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset) 1532 { 1533 Channel *nc; 1534 int newsock; 1535 struct sockaddr_storage addr; 1536 socklen_t addrlen; 1537 1538 if (FD_ISSET(c->sock, readset)) { 1539 addrlen = sizeof(addr); 1540 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1541 if (newsock < 0) { 1542 error("accept from auth socket: %.100s", strerror(errno)); 1543 return; 1544 } 1545 nc = channel_new("accepted auth socket", 1546 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1547 c->local_window_max, c->local_maxpacket, 1548 0, "accepted auth socket", 1); 1549 if (compat20) { 1550 packet_start(SSH2_MSG_CHANNEL_OPEN); 1551 packet_put_cstring("auth-agent@openssh.com"); 1552 packet_put_int(nc->self); 1553 packet_put_int(c->local_window_max); 1554 packet_put_int(c->local_maxpacket); 1555 } else { 1556 packet_start(SSH_SMSG_AGENT_OPEN); 1557 packet_put_int(nc->self); 1558 } 1559 packet_send(); 1560 } 1561 } 1562 1563 /* ARGSUSED */ 1564 static void 1565 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset) 1566 { 1567 int err = 0, sock; 1568 socklen_t sz = sizeof(err); 1569 1570 if (FD_ISSET(c->sock, writeset)) { 1571 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { 1572 err = errno; 1573 error("getsockopt SO_ERROR failed"); 1574 } 1575 if (err == 0) { 1576 debug("channel %d: connected to %s port %d", 1577 c->self, c->connect_ctx.host, c->connect_ctx.port); 1578 channel_connect_ctx_free(&c->connect_ctx); 1579 c->type = SSH_CHANNEL_OPEN; 1580 if (compat20) { 1581 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1582 packet_put_int(c->remote_id); 1583 packet_put_int(c->self); 1584 packet_put_int(c->local_window); 1585 packet_put_int(c->local_maxpacket); 1586 } else { 1587 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1588 packet_put_int(c->remote_id); 1589 packet_put_int(c->self); 1590 } 1591 } else { 1592 debug("channel %d: connection failed: %s", 1593 c->self, strerror(err)); 1594 /* Try next address, if any */ 1595 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1596 close(c->sock); 1597 c->sock = c->rfd = c->wfd = sock; 1598 channel_max_fd = channel_find_maxfd(); 1599 return; 1600 } 1601 /* Exhausted all addresses */ 1602 error("connect_to %.100s port %d: failed.", 1603 c->connect_ctx.host, c->connect_ctx.port); 1604 channel_connect_ctx_free(&c->connect_ctx); 1605 if (compat20) { 1606 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1607 packet_put_int(c->remote_id); 1608 packet_put_int(SSH2_OPEN_CONNECT_FAILED); 1609 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1610 packet_put_cstring(strerror(err)); 1611 packet_put_cstring(""); 1612 } 1613 } else { 1614 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1615 packet_put_int(c->remote_id); 1616 } 1617 chan_mark_dead(c); 1618 } 1619 packet_send(); 1620 } 1621 } 1622 1623 /* ARGSUSED */ 1624 static int 1625 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset) 1626 { 1627 char buf[CHAN_RBUF]; 1628 int len, force; 1629 1630 force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; 1631 if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) { 1632 errno = 0; 1633 len = read(c->rfd, buf, sizeof(buf)); 1634 if (len < 0 && (errno == EINTR || 1635 ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) 1636 return 1; 1637 #ifndef PTY_ZEROREAD 1638 if (len <= 0) { 1639 #else 1640 if ((!c->isatty && len <= 0) || 1641 (c->isatty && (len < 0 || (len == 0 && errno != 0)))) { 1642 #endif 1643 debug2("channel %d: read<=0 rfd %d len %d", 1644 c->self, c->rfd, len); 1645 if (c->type != SSH_CHANNEL_OPEN) { 1646 debug2("channel %d: not open", c->self); 1647 chan_mark_dead(c); 1648 return -1; 1649 } else if (compat13) { 1650 buffer_clear(&c->output); 1651 c->type = SSH_CHANNEL_INPUT_DRAINING; 1652 debug2("channel %d: input draining.", c->self); 1653 } else { 1654 chan_read_failed(c); 1655 } 1656 return -1; 1657 } 1658 if (c->input_filter != NULL) { 1659 if (c->input_filter(c, buf, len) == -1) { 1660 debug2("channel %d: filter stops", c->self); 1661 chan_read_failed(c); 1662 } 1663 } else if (c->datagram) { 1664 buffer_put_string(&c->input, buf, len); 1665 } else { 1666 buffer_append(&c->input, buf, len); 1667 } 1668 } 1669 return 1; 1670 } 1671 1672 /* ARGSUSED */ 1673 static int 1674 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset) 1675 { 1676 struct termios tio; 1677 u_char *data = NULL, *buf; 1678 u_int dlen, olen = 0; 1679 int len; 1680 1681 /* Send buffered output data to the socket. */ 1682 if (c->wfd != -1 && 1683 FD_ISSET(c->wfd, writeset) && 1684 buffer_len(&c->output) > 0) { 1685 olen = buffer_len(&c->output); 1686 if (c->output_filter != NULL) { 1687 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) { 1688 debug2("channel %d: filter stops", c->self); 1689 if (c->type != SSH_CHANNEL_OPEN) 1690 chan_mark_dead(c); 1691 else 1692 chan_write_failed(c); 1693 return -1; 1694 } 1695 } else if (c->datagram) { 1696 buf = data = buffer_get_string(&c->output, &dlen); 1697 } else { 1698 buf = data = buffer_ptr(&c->output); 1699 dlen = buffer_len(&c->output); 1700 } 1701 1702 if (c->datagram) { 1703 /* ignore truncated writes, datagrams might get lost */ 1704 len = write(c->wfd, buf, dlen); 1705 xfree(data); 1706 if (len < 0 && (errno == EINTR || errno == EAGAIN || 1707 errno == EWOULDBLOCK)) 1708 return 1; 1709 if (len <= 0) { 1710 if (c->type != SSH_CHANNEL_OPEN) 1711 chan_mark_dead(c); 1712 else 1713 chan_write_failed(c); 1714 return -1; 1715 } 1716 goto out; 1717 } 1718 #ifdef _AIX 1719 /* XXX: Later AIX versions can't push as much data to tty */ 1720 if (compat20 && c->wfd_isatty) 1721 dlen = MIN(dlen, 8*1024); 1722 #endif 1723 1724 len = write(c->wfd, buf, dlen); 1725 if (len < 0 && 1726 (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) 1727 return 1; 1728 if (len <= 0) { 1729 if (c->type != SSH_CHANNEL_OPEN) { 1730 debug2("channel %d: not open", c->self); 1731 chan_mark_dead(c); 1732 return -1; 1733 } else if (compat13) { 1734 buffer_clear(&c->output); 1735 debug2("channel %d: input draining.", c->self); 1736 c->type = SSH_CHANNEL_INPUT_DRAINING; 1737 } else { 1738 chan_write_failed(c); 1739 } 1740 return -1; 1741 } 1742 #ifndef BROKEN_TCGETATTR_ICANON 1743 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') { 1744 if (tcgetattr(c->wfd, &tio) == 0 && 1745 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 1746 /* 1747 * Simulate echo to reduce the impact of 1748 * traffic analysis. We need to match the 1749 * size of a SSH2_MSG_CHANNEL_DATA message 1750 * (4 byte channel id + buf) 1751 */ 1752 packet_send_ignore(4 + len); 1753 packet_send(); 1754 } 1755 } 1756 #endif 1757 buffer_consume(&c->output, len); 1758 } 1759 out: 1760 if (compat20 && olen > 0) 1761 c->local_consumed += olen - buffer_len(&c->output); 1762 return 1; 1763 } 1764 1765 static int 1766 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset) 1767 { 1768 char buf[CHAN_RBUF]; 1769 int len; 1770 1771 /** XXX handle drain efd, too */ 1772 if (c->efd != -1) { 1773 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1774 FD_ISSET(c->efd, writeset) && 1775 buffer_len(&c->extended) > 0) { 1776 len = write(c->efd, buffer_ptr(&c->extended), 1777 buffer_len(&c->extended)); 1778 debug2("channel %d: written %d to efd %d", 1779 c->self, len, c->efd); 1780 if (len < 0 && (errno == EINTR || errno == EAGAIN || 1781 errno == EWOULDBLOCK)) 1782 return 1; 1783 if (len <= 0) { 1784 debug2("channel %d: closing write-efd %d", 1785 c->self, c->efd); 1786 channel_close_fd(&c->efd); 1787 } else { 1788 buffer_consume(&c->extended, len); 1789 c->local_consumed += len; 1790 } 1791 } else if (c->efd != -1 && 1792 (c->extended_usage == CHAN_EXTENDED_READ || 1793 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1794 (c->detach_close || FD_ISSET(c->efd, readset))) { 1795 len = read(c->efd, buf, sizeof(buf)); 1796 debug2("channel %d: read %d from efd %d", 1797 c->self, len, c->efd); 1798 if (len < 0 && (errno == EINTR || ((errno == EAGAIN || 1799 errno == EWOULDBLOCK) && !c->detach_close))) 1800 return 1; 1801 if (len <= 0) { 1802 debug2("channel %d: closing read-efd %d", 1803 c->self, c->efd); 1804 channel_close_fd(&c->efd); 1805 } else { 1806 if (c->extended_usage == CHAN_EXTENDED_IGNORE) { 1807 debug3("channel %d: discard efd", 1808 c->self); 1809 } else 1810 buffer_append(&c->extended, buf, len); 1811 } 1812 } 1813 } 1814 return 1; 1815 } 1816 1817 static int 1818 channel_check_window(Channel *c) 1819 { 1820 if (c->type == SSH_CHANNEL_OPEN && 1821 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 1822 ((c->local_window_max - c->local_window > 1823 c->local_maxpacket*3) || 1824 c->local_window < c->local_window_max/2) && 1825 c->local_consumed > 0) { 1826 u_int addition = 0; 1827 /* adjust max window size if we are in a dynamic environment */ 1828 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) { 1829 /* grow the window somewhat aggressively to maintain pressure */ 1830 addition = 1.5*(c->tcpwinsz - c->local_window_max); 1831 c->local_window_max += addition; 1832 } 1833 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 1834 packet_put_int(c->remote_id); 1835 packet_put_int(c->local_consumed + addition); 1836 packet_send(); 1837 debug2("channel %d: window %d sent adjust %d", 1838 c->self, c->local_window, 1839 c->local_consumed); 1840 c->local_window += c->local_consumed + addition; 1841 c->local_consumed = 0; 1842 } 1843 return 1; 1844 } 1845 1846 static void 1847 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset) 1848 { 1849 channel_handle_rfd(c, readset, writeset); 1850 channel_handle_wfd(c, readset, writeset); 1851 if (!compat20) 1852 return; 1853 channel_handle_efd(c, readset, writeset); 1854 channel_check_window(c); 1855 } 1856 1857 static u_int 1858 read_mux(Channel *c, u_int need) 1859 { 1860 char buf[CHAN_RBUF]; 1861 int len; 1862 u_int rlen; 1863 1864 if (buffer_len(&c->input) < need) { 1865 rlen = need - buffer_len(&c->input); 1866 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF)); 1867 if (len <= 0) { 1868 if (errno != EINTR && errno != EAGAIN) { 1869 debug2("channel %d: ctl read<=0 rfd %d len %d", 1870 c->self, c->rfd, len); 1871 chan_read_failed(c); 1872 return 0; 1873 } 1874 } else 1875 buffer_append(&c->input, buf, len); 1876 } 1877 return buffer_len(&c->input); 1878 } 1879 1880 static void 1881 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1882 { 1883 u_int need; 1884 ssize_t len; 1885 1886 if (!compat20) 1887 fatal("%s: entered with !compat20", __func__); 1888 1889 if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) && 1890 (c->istate == CHAN_INPUT_OPEN || 1891 c->istate == CHAN_INPUT_WAIT_DRAIN)) { 1892 /* 1893 * Don't not read past the precise end of packets to 1894 * avoid disrupting fd passing. 1895 */ 1896 if (read_mux(c, 4) < 4) /* read header */ 1897 return; 1898 need = get_u32(buffer_ptr(&c->input)); 1899 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 1900 if (need > CHANNEL_MUX_MAX_PACKET) { 1901 debug2("channel %d: packet too big %u > %u", 1902 c->self, CHANNEL_MUX_MAX_PACKET, need); 1903 chan_rcvd_oclose(c); 1904 return; 1905 } 1906 if (read_mux(c, need + 4) < need + 4) /* read body */ 1907 return; 1908 if (c->mux_rcb(c) != 0) { 1909 debug("channel %d: mux_rcb failed", c->self); 1910 chan_mark_dead(c); 1911 return; 1912 } 1913 } 1914 1915 if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) && 1916 buffer_len(&c->output) > 0) { 1917 len = write(c->wfd, buffer_ptr(&c->output), 1918 buffer_len(&c->output)); 1919 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1920 return; 1921 if (len <= 0) { 1922 chan_mark_dead(c); 1923 return; 1924 } 1925 buffer_consume(&c->output, len); 1926 } 1927 } 1928 1929 static void 1930 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset) 1931 { 1932 Channel *nc; 1933 struct sockaddr_storage addr; 1934 socklen_t addrlen; 1935 int newsock; 1936 uid_t euid; 1937 gid_t egid; 1938 1939 if (!FD_ISSET(c->sock, readset)) 1940 return; 1941 1942 debug("multiplexing control connection"); 1943 1944 /* 1945 * Accept connection on control socket 1946 */ 1947 memset(&addr, 0, sizeof(addr)); 1948 addrlen = sizeof(addr); 1949 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 1950 &addrlen)) == -1) { 1951 error("%s accept: %s", __func__, strerror(errno)); 1952 return; 1953 } 1954 1955 if (getpeereid(newsock, &euid, &egid) < 0) { 1956 error("%s getpeereid failed: %s", __func__, 1957 strerror(errno)); 1958 close(newsock); 1959 return; 1960 } 1961 if ((euid != 0) && (getuid() != euid)) { 1962 error("multiplex uid mismatch: peer euid %u != uid %u", 1963 (u_int)euid, (u_int)getuid()); 1964 close(newsock); 1965 return; 1966 } 1967 nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT, 1968 newsock, newsock, -1, c->local_window_max, 1969 c->local_maxpacket, 0, "mux-control", 1); 1970 nc->mux_rcb = c->mux_rcb; 1971 debug3("%s: new mux channel %d fd %d", __func__, 1972 nc->self, nc->sock); 1973 /* establish state */ 1974 nc->mux_rcb(nc); 1975 /* mux state transitions must not elicit protocol messages */ 1976 nc->flags |= CHAN_LOCAL; 1977 } 1978 1979 /* ARGSUSED */ 1980 static void 1981 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset) 1982 { 1983 int len; 1984 1985 /* Send buffered output data to the socket. */ 1986 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { 1987 len = write(c->sock, buffer_ptr(&c->output), 1988 buffer_len(&c->output)); 1989 if (len <= 0) 1990 buffer_clear(&c->output); 1991 else 1992 buffer_consume(&c->output, len); 1993 } 1994 } 1995 1996 static void 1997 channel_handler_init_20(void) 1998 { 1999 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2000 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2001 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2002 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2003 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2004 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2005 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2006 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2007 channel_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2008 channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2009 2010 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2011 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2012 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2013 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2014 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2015 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2016 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2017 channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2018 channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2019 } 2020 2021 static void 2022 channel_handler_init_13(void) 2023 { 2024 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; 2025 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; 2026 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2027 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2028 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2029 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; 2030 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; 2031 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2032 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2033 2034 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2035 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2036 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2037 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2038 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; 2039 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2040 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2041 } 2042 2043 static void 2044 channel_handler_init_15(void) 2045 { 2046 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2047 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2048 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2049 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2050 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2051 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2052 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2053 2054 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2055 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2056 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2057 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2058 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2059 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2060 } 2061 2062 static void 2063 channel_handler_init(void) 2064 { 2065 int i; 2066 2067 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { 2068 channel_pre[i] = NULL; 2069 channel_post[i] = NULL; 2070 } 2071 if (compat20) 2072 channel_handler_init_20(); 2073 else if (compat13) 2074 channel_handler_init_13(); 2075 else 2076 channel_handler_init_15(); 2077 } 2078 2079 /* gc dead channels */ 2080 static void 2081 channel_garbage_collect(Channel *c) 2082 { 2083 if (c == NULL) 2084 return; 2085 if (c->detach_user != NULL) { 2086 if (!chan_is_dead(c, c->detach_close)) 2087 return; 2088 debug2("channel %d: gc: notify user", c->self); 2089 c->detach_user(c->self, NULL); 2090 /* if we still have a callback */ 2091 if (c->detach_user != NULL) 2092 return; 2093 debug2("channel %d: gc: user detached", c->self); 2094 } 2095 if (!chan_is_dead(c, 1)) 2096 return; 2097 debug2("channel %d: garbage collecting", c->self); 2098 channel_free(c); 2099 } 2100 2101 static void 2102 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset) 2103 { 2104 static int did_init = 0; 2105 u_int i, oalloc; 2106 Channel *c; 2107 2108 if (!did_init) { 2109 channel_handler_init(); 2110 did_init = 1; 2111 } 2112 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) { 2113 c = channels[i]; 2114 if (c == NULL) 2115 continue; 2116 if (c->delayed) { 2117 if (ftab == channel_pre) 2118 c->delayed = 0; 2119 else 2120 continue; 2121 } 2122 if (ftab[c->type] != NULL) 2123 (*ftab[c->type])(c, readset, writeset); 2124 channel_garbage_collect(c); 2125 } 2126 } 2127 2128 /* 2129 * Allocate/update select bitmasks and add any bits relevant to channels in 2130 * select bitmasks. 2131 */ 2132 void 2133 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, 2134 u_int *nallocp, int rekeying) 2135 { 2136 u_int n, sz, nfdset; 2137 2138 n = MAX(*maxfdp, channel_max_fd); 2139 2140 nfdset = howmany(n+1, NFDBITS); 2141 /* Explicitly test here, because xrealloc isn't always called */ 2142 if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask)) 2143 fatal("channel_prepare_select: max_fd (%d) is too large", n); 2144 sz = nfdset * sizeof(fd_mask); 2145 2146 /* perhaps check sz < nalloc/2 and shrink? */ 2147 if (*readsetp == NULL || sz > *nallocp) { 2148 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask)); 2149 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask)); 2150 *nallocp = sz; 2151 } 2152 *maxfdp = n; 2153 memset(*readsetp, 0, sz); 2154 memset(*writesetp, 0, sz); 2155 2156 if (!rekeying) 2157 channel_handler(channel_pre, *readsetp, *writesetp); 2158 } 2159 2160 /* 2161 * After select, perform any appropriate operations for channels which have 2162 * events pending. 2163 */ 2164 void 2165 channel_after_select(fd_set *readset, fd_set *writeset) 2166 { 2167 channel_handler(channel_post, readset, writeset); 2168 } 2169 2170 2171 /* If there is data to send to the connection, enqueue some of it now. */ 2172 int 2173 channel_output_poll(void) 2174 { 2175 Channel *c; 2176 u_int i, len; 2177 int packet_length = 0; 2178 2179 for (i = 0; i < channels_alloc; i++) { 2180 c = channels[i]; 2181 if (c == NULL) 2182 continue; 2183 2184 /* 2185 * We are only interested in channels that can have buffered 2186 * incoming data. 2187 */ 2188 if (compat13) { 2189 if (c->type != SSH_CHANNEL_OPEN && 2190 c->type != SSH_CHANNEL_INPUT_DRAINING) 2191 continue; 2192 } else { 2193 if (c->type != SSH_CHANNEL_OPEN) 2194 continue; 2195 } 2196 if (compat20 && 2197 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2198 /* XXX is this true? */ 2199 debug3("channel %d: will not send data after close", c->self); 2200 continue; 2201 } 2202 2203 /* Get the amount of buffered data for this channel. */ 2204 if ((c->istate == CHAN_INPUT_OPEN || 2205 c->istate == CHAN_INPUT_WAIT_DRAIN) && 2206 (len = buffer_len(&c->input)) > 0) { 2207 if (c->datagram) { 2208 if (len > 0) { 2209 u_char *data; 2210 u_int dlen; 2211 2212 data = buffer_get_string(&c->input, 2213 &dlen); 2214 if (dlen > c->remote_window || 2215 dlen > c->remote_maxpacket) { 2216 debug("channel %d: datagram " 2217 "too big for channel", 2218 c->self); 2219 xfree(data); 2220 continue; 2221 } 2222 packet_start(SSH2_MSG_CHANNEL_DATA); 2223 packet_put_int(c->remote_id); 2224 packet_put_string(data, dlen); 2225 packet_length = packet_send(); 2226 c->remote_window -= dlen + 4; 2227 xfree(data); 2228 } 2229 continue; 2230 } 2231 /* 2232 * Send some data for the other side over the secure 2233 * connection. 2234 */ 2235 if (compat20) { 2236 if (len > c->remote_window) 2237 len = c->remote_window; 2238 if (len > c->remote_maxpacket) 2239 len = c->remote_maxpacket; 2240 } else { 2241 if (packet_is_interactive()) { 2242 if (len > 1024) 2243 len = 512; 2244 } else { 2245 /* Keep the packets at reasonable size. */ 2246 if (len > packet_get_maxsize()/2) 2247 len = packet_get_maxsize()/2; 2248 } 2249 } 2250 if (len > 0) { 2251 packet_start(compat20 ? 2252 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); 2253 packet_put_int(c->remote_id); 2254 packet_put_string(buffer_ptr(&c->input), len); 2255 packet_length = packet_send(); 2256 buffer_consume(&c->input, len); 2257 c->remote_window -= len; 2258 } 2259 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2260 if (compat13) 2261 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); 2262 /* 2263 * input-buffer is empty and read-socket shutdown: 2264 * tell peer, that we will not send more data: send IEOF. 2265 * hack for extended data: delay EOF if EFD still in use. 2266 */ 2267 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2268 debug2("channel %d: ibuf_empty delayed efd %d/(%d)", 2269 c->self, c->efd, buffer_len(&c->extended)); 2270 else 2271 chan_ibuf_empty(c); 2272 } 2273 /* Send extended data, i.e. stderr */ 2274 if (compat20 && 2275 !(c->flags & CHAN_EOF_SENT) && 2276 c->remote_window > 0 && 2277 (len = buffer_len(&c->extended)) > 0 && 2278 c->extended_usage == CHAN_EXTENDED_READ) { 2279 debug2("channel %d: rwin %u elen %u euse %d", 2280 c->self, c->remote_window, buffer_len(&c->extended), 2281 c->extended_usage); 2282 if (len > c->remote_window) 2283 len = c->remote_window; 2284 if (len > c->remote_maxpacket) 2285 len = c->remote_maxpacket; 2286 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); 2287 packet_put_int(c->remote_id); 2288 packet_put_int(SSH2_EXTENDED_DATA_STDERR); 2289 packet_put_string(buffer_ptr(&c->extended), len); 2290 packet_length = packet_send(); 2291 buffer_consume(&c->extended, len); 2292 c->remote_window -= len; 2293 debug2("channel %d: sent ext data %d", c->self, len); 2294 } 2295 } 2296 return (packet_length); 2297 } 2298 2299 2300 /* -- protocol input */ 2301 2302 /* ARGSUSED */ 2303 void 2304 channel_input_data(int type, u_int32_t seq, void *ctxt) 2305 { 2306 int id; 2307 char *data; 2308 u_int data_len, win_len; 2309 Channel *c; 2310 2311 /* Get the channel number and verify it. */ 2312 id = packet_get_int(); 2313 c = channel_lookup(id); 2314 if (c == NULL) 2315 packet_disconnect("Received data for nonexistent channel %d.", id); 2316 2317 /* Ignore any data for non-open channels (might happen on close) */ 2318 if (c->type != SSH_CHANNEL_OPEN && 2319 c->type != SSH_CHANNEL_X11_OPEN) 2320 return; 2321 2322 /* Get the data. */ 2323 data = packet_get_string_ptr(&data_len); 2324 win_len = data_len; 2325 if (c->datagram) 2326 win_len += 4; /* string length header */ 2327 2328 /* 2329 * Ignore data for protocol > 1.3 if output end is no longer open. 2330 * For protocol 2 the sending side is reducing its window as it sends 2331 * data, so we must 'fake' consumption of the data in order to ensure 2332 * that window updates are sent back. Otherwise the connection might 2333 * deadlock. 2334 */ 2335 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { 2336 if (compat20) { 2337 c->local_window -= win_len; 2338 c->local_consumed += win_len; 2339 } 2340 return; 2341 } 2342 2343 if (compat20) { 2344 if (win_len > c->local_maxpacket) { 2345 logit("channel %d: rcvd big packet %d, maxpack %d", 2346 c->self, win_len, c->local_maxpacket); 2347 } 2348 if (win_len > c->local_window) { 2349 logit("channel %d: rcvd too much data %d, win %d", 2350 c->self, win_len, c->local_window); 2351 return; 2352 } 2353 c->local_window -= win_len; 2354 } 2355 if (c->datagram) 2356 buffer_put_string(&c->output, data, data_len); 2357 else 2358 buffer_append(&c->output, data, data_len); 2359 packet_check_eom(); 2360 } 2361 2362 /* ARGSUSED */ 2363 void 2364 channel_input_extended_data(int type, u_int32_t seq, void *ctxt) 2365 { 2366 int id; 2367 char *data; 2368 u_int data_len, tcode; 2369 Channel *c; 2370 2371 /* Get the channel number and verify it. */ 2372 id = packet_get_int(); 2373 c = channel_lookup(id); 2374 2375 if (c == NULL) 2376 packet_disconnect("Received extended_data for bad channel %d.", id); 2377 if (c->type != SSH_CHANNEL_OPEN) { 2378 logit("channel %d: ext data for non open", id); 2379 return; 2380 } 2381 if (c->flags & CHAN_EOF_RCVD) { 2382 if (datafellows & SSH_BUG_EXTEOF) 2383 debug("channel %d: accepting ext data after eof", id); 2384 else 2385 packet_disconnect("Received extended_data after EOF " 2386 "on channel %d.", id); 2387 } 2388 tcode = packet_get_int(); 2389 if (c->efd == -1 || 2390 c->extended_usage != CHAN_EXTENDED_WRITE || 2391 tcode != SSH2_EXTENDED_DATA_STDERR) { 2392 logit("channel %d: bad ext data", c->self); 2393 return; 2394 } 2395 data = packet_get_string(&data_len); 2396 packet_check_eom(); 2397 if (data_len > c->local_window) { 2398 logit("channel %d: rcvd too much extended_data %d, win %d", 2399 c->self, data_len, c->local_window); 2400 xfree(data); 2401 return; 2402 } 2403 debug2("channel %d: rcvd ext data %d", c->self, data_len); 2404 c->local_window -= data_len; 2405 buffer_append(&c->extended, data, data_len); 2406 xfree(data); 2407 } 2408 2409 /* ARGSUSED */ 2410 void 2411 channel_input_ieof(int type, u_int32_t seq, void *ctxt) 2412 { 2413 int id; 2414 Channel *c; 2415 2416 id = packet_get_int(); 2417 packet_check_eom(); 2418 c = channel_lookup(id); 2419 if (c == NULL) 2420 packet_disconnect("Received ieof for nonexistent channel %d.", id); 2421 chan_rcvd_ieof(c); 2422 2423 /* XXX force input close */ 2424 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 2425 debug("channel %d: FORCE input drain", c->self); 2426 c->istate = CHAN_INPUT_WAIT_DRAIN; 2427 if (buffer_len(&c->input) == 0) 2428 chan_ibuf_empty(c); 2429 } 2430 2431 } 2432 2433 /* ARGSUSED */ 2434 void 2435 channel_input_close(int type, u_int32_t seq, void *ctxt) 2436 { 2437 int id; 2438 Channel *c; 2439 2440 id = packet_get_int(); 2441 packet_check_eom(); 2442 c = channel_lookup(id); 2443 if (c == NULL) 2444 packet_disconnect("Received close for nonexistent channel %d.", id); 2445 2446 /* 2447 * Send a confirmation that we have closed the channel and no more 2448 * data is coming for it. 2449 */ 2450 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); 2451 packet_put_int(c->remote_id); 2452 packet_send(); 2453 2454 /* 2455 * If the channel is in closed state, we have sent a close request, 2456 * and the other side will eventually respond with a confirmation. 2457 * Thus, we cannot free the channel here, because then there would be 2458 * no-one to receive the confirmation. The channel gets freed when 2459 * the confirmation arrives. 2460 */ 2461 if (c->type != SSH_CHANNEL_CLOSED) { 2462 /* 2463 * Not a closed channel - mark it as draining, which will 2464 * cause it to be freed later. 2465 */ 2466 buffer_clear(&c->input); 2467 c->type = SSH_CHANNEL_OUTPUT_DRAINING; 2468 } 2469 } 2470 2471 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ 2472 /* ARGSUSED */ 2473 void 2474 channel_input_oclose(int type, u_int32_t seq, void *ctxt) 2475 { 2476 int id = packet_get_int(); 2477 Channel *c = channel_lookup(id); 2478 2479 packet_check_eom(); 2480 if (c == NULL) 2481 packet_disconnect("Received oclose for nonexistent channel %d.", id); 2482 chan_rcvd_oclose(c); 2483 } 2484 2485 /* ARGSUSED */ 2486 void 2487 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) 2488 { 2489 int id = packet_get_int(); 2490 Channel *c = channel_lookup(id); 2491 2492 packet_check_eom(); 2493 if (c == NULL) 2494 packet_disconnect("Received close confirmation for " 2495 "out-of-range channel %d.", id); 2496 if (c->type != SSH_CHANNEL_CLOSED) 2497 packet_disconnect("Received close confirmation for " 2498 "non-closed channel %d (type %d).", id, c->type); 2499 channel_free(c); 2500 } 2501 2502 /* ARGSUSED */ 2503 void 2504 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) 2505 { 2506 int id, remote_id; 2507 Channel *c; 2508 2509 id = packet_get_int(); 2510 c = channel_lookup(id); 2511 2512 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2513 packet_disconnect("Received open confirmation for " 2514 "non-opening channel %d.", id); 2515 remote_id = packet_get_int(); 2516 /* Record the remote channel number and mark that the channel is now open. */ 2517 c->remote_id = remote_id; 2518 c->type = SSH_CHANNEL_OPEN; 2519 2520 if (compat20) { 2521 c->remote_window = packet_get_int(); 2522 c->remote_maxpacket = packet_get_int(); 2523 if (c->open_confirm) { 2524 debug2("callback start"); 2525 c->open_confirm(c->self, 1, c->open_confirm_ctx); 2526 debug2("callback done"); 2527 } 2528 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 2529 c->remote_window, c->remote_maxpacket); 2530 } 2531 packet_check_eom(); 2532 } 2533 2534 static char * 2535 reason2txt(int reason) 2536 { 2537 switch (reason) { 2538 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 2539 return "administratively prohibited"; 2540 case SSH2_OPEN_CONNECT_FAILED: 2541 return "connect failed"; 2542 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 2543 return "unknown channel type"; 2544 case SSH2_OPEN_RESOURCE_SHORTAGE: 2545 return "resource shortage"; 2546 } 2547 return "unknown reason"; 2548 } 2549 2550 /* ARGSUSED */ 2551 void 2552 channel_input_open_failure(int type, u_int32_t seq, void *ctxt) 2553 { 2554 int id, reason; 2555 char *msg = NULL, *lang = NULL; 2556 Channel *c; 2557 2558 id = packet_get_int(); 2559 c = channel_lookup(id); 2560 2561 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2562 packet_disconnect("Received open failure for " 2563 "non-opening channel %d.", id); 2564 if (compat20) { 2565 reason = packet_get_int(); 2566 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 2567 msg = packet_get_string(NULL); 2568 lang = packet_get_string(NULL); 2569 } 2570 logit("channel %d: open failed: %s%s%s", id, 2571 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 2572 if (msg != NULL) 2573 xfree(msg); 2574 if (lang != NULL) 2575 xfree(lang); 2576 if (c->open_confirm) { 2577 debug2("callback start"); 2578 c->open_confirm(c->self, 0, c->open_confirm_ctx); 2579 debug2("callback done"); 2580 } 2581 } 2582 packet_check_eom(); 2583 /* Schedule the channel for cleanup/deletion. */ 2584 chan_mark_dead(c); 2585 } 2586 2587 /* ARGSUSED */ 2588 void 2589 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) 2590 { 2591 Channel *c; 2592 int id; 2593 u_int adjust; 2594 2595 if (!compat20) 2596 return; 2597 2598 /* Get the channel number and verify it. */ 2599 id = packet_get_int(); 2600 c = channel_lookup(id); 2601 2602 if (c == NULL) { 2603 logit("Received window adjust for non-open channel %d.", id); 2604 return; 2605 } 2606 adjust = packet_get_int(); 2607 packet_check_eom(); 2608 debug2("channel %d: rcvd adjust %u", id, adjust); 2609 c->remote_window += adjust; 2610 } 2611 2612 /* ARGSUSED */ 2613 void 2614 channel_input_port_open(int type, u_int32_t seq, void *ctxt) 2615 { 2616 Channel *c = NULL; 2617 u_short host_port; 2618 char *host, *originator_string; 2619 int remote_id; 2620 2621 remote_id = packet_get_int(); 2622 host = packet_get_string(NULL); 2623 host_port = packet_get_int(); 2624 2625 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 2626 originator_string = packet_get_string(NULL); 2627 } else { 2628 originator_string = xstrdup("unknown (remote did not supply name)"); 2629 } 2630 packet_check_eom(); 2631 c = channel_connect_to(host, host_port, 2632 "connected socket", originator_string); 2633 xfree(originator_string); 2634 xfree(host); 2635 if (c == NULL) { 2636 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 2637 packet_put_int(remote_id); 2638 packet_send(); 2639 } else 2640 c->remote_id = remote_id; 2641 } 2642 2643 /* ARGSUSED */ 2644 void 2645 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt) 2646 { 2647 Channel *c; 2648 struct channel_confirm *cc; 2649 int id; 2650 2651 /* Reset keepalive timeout */ 2652 packet_set_alive_timeouts(0); 2653 2654 id = packet_get_int(); 2655 packet_check_eom(); 2656 2657 debug2("channel_input_status_confirm: type %d id %d", type, id); 2658 2659 if ((c = channel_lookup(id)) == NULL) { 2660 logit("channel_input_status_confirm: %d: unknown", id); 2661 return; 2662 } 2663 ; 2664 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 2665 return; 2666 cc->cb(type, c, cc->ctx); 2667 TAILQ_REMOVE(&c->status_confirms, cc, entry); 2668 bzero(cc, sizeof(*cc)); 2669 xfree(cc); 2670 } 2671 2672 /* -- tcp forwarding */ 2673 2674 void 2675 channel_set_af(int af) 2676 { 2677 IPv4or6 = af; 2678 } 2679 2680 2681 void 2682 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size) 2683 { 2684 hpn_disabled = external_hpn_disabled; 2685 hpn_buffer_size = external_hpn_buffer_size; 2686 debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size); 2687 } 2688 2689 static int 2690 channel_setup_fwd_listener(int type, const char *listen_addr, 2691 u_short listen_port, int *allocated_listen_port, 2692 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2693 { 2694 Channel *c; 2695 int sock, r, success = 0, wildcard = 0, is_client; 2696 struct addrinfo hints, *ai, *aitop; 2697 const char *host, *addr; 2698 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 2699 in_port_t *lport_p; 2700 2701 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 2702 listen_addr : host_to_connect; 2703 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 2704 2705 if (host == NULL) { 2706 error("No forward host name."); 2707 return 0; 2708 } 2709 if (strlen(host) >= NI_MAXHOST) { 2710 error("Forward host name too long."); 2711 return 0; 2712 } 2713 2714 /* 2715 * Determine whether or not a port forward listens to loopback, 2716 * specified address or wildcard. On the client, a specified bind 2717 * address will always override gateway_ports. On the server, a 2718 * gateway_ports of 1 (``yes'') will override the client's 2719 * specification and force a wildcard bind, whereas a value of 2 2720 * (``clientspecified'') will bind to whatever address the client 2721 * asked for. 2722 * 2723 * Special-case listen_addrs are: 2724 * 2725 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 2726 * "" (empty string), "*" -> wildcard v4/v6 2727 * "localhost" -> loopback v4/v6 2728 */ 2729 addr = NULL; 2730 if (listen_addr == NULL) { 2731 /* No address specified: default to gateway_ports setting */ 2732 if (gateway_ports) 2733 wildcard = 1; 2734 } else if (gateway_ports || is_client) { 2735 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 2736 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 2737 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 2738 (!is_client && gateway_ports == 1)) 2739 wildcard = 1; 2740 else if (strcmp(listen_addr, "localhost") != 0) 2741 addr = listen_addr; 2742 } 2743 2744 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s", 2745 type, wildcard, (addr == NULL) ? "NULL" : addr); 2746 2747 /* 2748 * getaddrinfo returns a loopback address if the hostname is 2749 * set to NULL and hints.ai_flags is not AI_PASSIVE 2750 */ 2751 memset(&hints, 0, sizeof(hints)); 2752 hints.ai_family = IPv4or6; 2753 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 2754 hints.ai_socktype = SOCK_STREAM; 2755 snprintf(strport, sizeof strport, "%d", listen_port); 2756 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 2757 if (addr == NULL) { 2758 /* This really shouldn't happen */ 2759 packet_disconnect("getaddrinfo: fatal error: %s", 2760 ssh_gai_strerror(r)); 2761 } else { 2762 error("channel_setup_fwd_listener: " 2763 "getaddrinfo(%.64s): %s", addr, 2764 ssh_gai_strerror(r)); 2765 } 2766 return 0; 2767 } 2768 if (allocated_listen_port != NULL) 2769 *allocated_listen_port = 0; 2770 for (ai = aitop; ai; ai = ai->ai_next) { 2771 switch (ai->ai_family) { 2772 case AF_INET: 2773 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 2774 sin_port; 2775 break; 2776 case AF_INET6: 2777 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 2778 sin6_port; 2779 break; 2780 default: 2781 continue; 2782 } 2783 /* 2784 * If allocating a port for -R forwards, then use the 2785 * same port for all address families. 2786 */ 2787 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 && 2788 allocated_listen_port != NULL && *allocated_listen_port > 0) 2789 *lport_p = htons(*allocated_listen_port); 2790 2791 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 2792 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 2793 error("channel_setup_fwd_listener: getnameinfo failed"); 2794 continue; 2795 } 2796 /* Create a port to listen for the host. */ 2797 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 2798 if (sock < 0) { 2799 /* this is no error since kernel may not support ipv6 */ 2800 verbose("socket: %.100s", strerror(errno)); 2801 continue; 2802 } 2803 2804 channel_set_reuseaddr(sock); 2805 if (ai->ai_family == AF_INET6) 2806 sock_set_v6only(sock); 2807 2808 debug("Local forwarding listening on %s port %s.", 2809 ntop, strport); 2810 2811 /* Bind the socket to the address. */ 2812 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 2813 /* address can be in use ipv6 address is already bound */ 2814 if (!ai->ai_next) 2815 error("bind: %.100s", strerror(errno)); 2816 else 2817 verbose("bind: %.100s", strerror(errno)); 2818 2819 close(sock); 2820 continue; 2821 } 2822 /* Start listening for connections on the socket. */ 2823 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 2824 error("listen: %.100s", strerror(errno)); 2825 close(sock); 2826 continue; 2827 } 2828 2829 /* 2830 * listen_port == 0 requests a dynamically allocated port - 2831 * record what we got. 2832 */ 2833 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 && 2834 allocated_listen_port != NULL && 2835 *allocated_listen_port == 0) { 2836 *allocated_listen_port = get_sock_port(sock, 1); 2837 debug("Allocated listen port %d", 2838 *allocated_listen_port); 2839 } 2840 2841 /* Allocate a channel number for the socket. */ 2842 /* explicitly test for hpn disabled option. if true use smaller window size */ 2843 if (hpn_disabled) 2844 c = channel_new("port listener", type, sock, sock, -1, 2845 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 2846 0, "port listener", 1); 2847 else 2848 c = channel_new("port listener", type, sock, sock, -1, 2849 hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 2850 0, "port listener", 1); 2851 c->path = xstrdup(host); 2852 c->host_port = port_to_connect; 2853 c->listening_port = listen_port; 2854 success = 1; 2855 } 2856 if (success == 0) 2857 error("channel_setup_fwd_listener: cannot listen to port: %d", 2858 listen_port); 2859 freeaddrinfo(aitop); 2860 return success; 2861 } 2862 2863 int 2864 channel_cancel_rport_listener(const char *host, u_short port) 2865 { 2866 u_int i; 2867 int found = 0; 2868 2869 for (i = 0; i < channels_alloc; i++) { 2870 Channel *c = channels[i]; 2871 2872 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER && 2873 strcmp(c->path, host) == 0 && c->listening_port == port) { 2874 debug2("%s: close channel %d", __func__, i); 2875 channel_free(c); 2876 found = 1; 2877 } 2878 } 2879 2880 return (found); 2881 } 2882 2883 /* protocol local port fwd, used by ssh (and sshd in v1) */ 2884 int 2885 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port, 2886 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2887 { 2888 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, 2889 listen_host, listen_port, NULL, host_to_connect, port_to_connect, 2890 gateway_ports); 2891 } 2892 2893 /* protocol v2 remote port fwd, used by sshd */ 2894 int 2895 channel_setup_remote_fwd_listener(const char *listen_address, 2896 u_short listen_port, int *allocated_listen_port, int gateway_ports) 2897 { 2898 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, 2899 listen_address, listen_port, allocated_listen_port, 2900 NULL, 0, gateway_ports); 2901 } 2902 2903 /* 2904 * Initiate forwarding of connections to port "port" on remote host through 2905 * the secure channel to host:port from local side. 2906 */ 2907 2908 int 2909 channel_request_remote_forwarding(const char *listen_host, u_short listen_port, 2910 const char *host_to_connect, u_short port_to_connect) 2911 { 2912 int type, success = 0; 2913 2914 /* Send the forward request to the remote side. */ 2915 if (compat20) { 2916 const char *address_to_bind; 2917 if (listen_host == NULL) { 2918 if (datafellows & SSH_BUG_RFWD_ADDR) 2919 address_to_bind = "127.0.0.1"; 2920 else 2921 address_to_bind = "localhost"; 2922 } else if (*listen_host == '\0' || 2923 strcmp(listen_host, "*") == 0) { 2924 if (datafellows & SSH_BUG_RFWD_ADDR) 2925 address_to_bind = "0.0.0.0"; 2926 else 2927 address_to_bind = ""; 2928 } else 2929 address_to_bind = listen_host; 2930 2931 packet_start(SSH2_MSG_GLOBAL_REQUEST); 2932 packet_put_cstring("tcpip-forward"); 2933 packet_put_char(1); /* boolean: want reply */ 2934 packet_put_cstring(address_to_bind); 2935 packet_put_int(listen_port); 2936 packet_send(); 2937 packet_write_wait(); 2938 /* Assume that server accepts the request */ 2939 success = 1; 2940 } else { 2941 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); 2942 packet_put_int(listen_port); 2943 packet_put_cstring(host_to_connect); 2944 packet_put_int(port_to_connect); 2945 packet_send(); 2946 packet_write_wait(); 2947 2948 /* Wait for response from the remote side. */ 2949 type = packet_read(); 2950 switch (type) { 2951 case SSH_SMSG_SUCCESS: 2952 success = 1; 2953 break; 2954 case SSH_SMSG_FAILURE: 2955 break; 2956 default: 2957 /* Unknown packet */ 2958 packet_disconnect("Protocol error for port forward request:" 2959 "received packet type %d.", type); 2960 } 2961 } 2962 if (success) { 2963 /* Record that connection to this host/port is permitted. */ 2964 permitted_opens = xrealloc(permitted_opens, 2965 num_permitted_opens + 1, sizeof(*permitted_opens)); 2966 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); 2967 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; 2968 permitted_opens[num_permitted_opens].listen_port = listen_port; 2969 num_permitted_opens++; 2970 } 2971 return (success ? 0 : -1); 2972 } 2973 2974 /* 2975 * Request cancellation of remote forwarding of connection host:port from 2976 * local side. 2977 */ 2978 void 2979 channel_request_rforward_cancel(const char *host, u_short port) 2980 { 2981 int i; 2982 2983 if (!compat20) 2984 return; 2985 2986 for (i = 0; i < num_permitted_opens; i++) { 2987 if (permitted_opens[i].host_to_connect != NULL && 2988 permitted_opens[i].listen_port == port) 2989 break; 2990 } 2991 if (i >= num_permitted_opens) { 2992 debug("%s: requested forward not found", __func__); 2993 return; 2994 } 2995 packet_start(SSH2_MSG_GLOBAL_REQUEST); 2996 packet_put_cstring("cancel-tcpip-forward"); 2997 packet_put_char(0); 2998 packet_put_cstring(host == NULL ? "" : host); 2999 packet_put_int(port); 3000 packet_send(); 3001 3002 permitted_opens[i].listen_port = 0; 3003 permitted_opens[i].port_to_connect = 0; 3004 xfree(permitted_opens[i].host_to_connect); 3005 permitted_opens[i].host_to_connect = NULL; 3006 } 3007 3008 /* 3009 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates 3010 * listening for the port, and sends back a success reply (or disconnect 3011 * message if there was an error). 3012 */ 3013 int 3014 channel_input_port_forward_request(int is_root, int gateway_ports) 3015 { 3016 u_short port, host_port; 3017 int success = 0; 3018 char *hostname; 3019 3020 /* Get arguments from the packet. */ 3021 port = packet_get_int(); 3022 hostname = packet_get_string(NULL); 3023 host_port = packet_get_int(); 3024 3025 #ifndef HAVE_CYGWIN 3026 /* 3027 * Check that an unprivileged user is not trying to forward a 3028 * privileged port. 3029 */ 3030 if (port < IPPORT_RESERVED && !is_root) 3031 packet_disconnect( 3032 "Requested forwarding of port %d but user is not root.", 3033 port); 3034 if (host_port == 0) 3035 packet_disconnect("Dynamic forwarding denied."); 3036 #endif 3037 3038 /* Initiate forwarding */ 3039 success = channel_setup_local_fwd_listener(NULL, port, hostname, 3040 host_port, gateway_ports); 3041 3042 /* Free the argument string. */ 3043 xfree(hostname); 3044 3045 return (success ? 0 : -1); 3046 } 3047 3048 /* 3049 * Permits opening to any host/port if permitted_opens[] is empty. This is 3050 * usually called by the server, because the user could connect to any port 3051 * anyway, and the server has no way to know but to trust the client anyway. 3052 */ 3053 void 3054 channel_permit_all_opens(void) 3055 { 3056 if (num_permitted_opens == 0) 3057 all_opens_permitted = 1; 3058 } 3059 3060 void 3061 channel_add_permitted_opens(char *host, int port) 3062 { 3063 debug("allow port forwarding to host %s port %d", host, port); 3064 3065 permitted_opens = xrealloc(permitted_opens, 3066 num_permitted_opens + 1, sizeof(*permitted_opens)); 3067 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); 3068 permitted_opens[num_permitted_opens].port_to_connect = port; 3069 num_permitted_opens++; 3070 3071 all_opens_permitted = 0; 3072 } 3073 3074 int 3075 channel_add_adm_permitted_opens(char *host, int port) 3076 { 3077 debug("config allows port forwarding to host %s port %d", host, port); 3078 3079 permitted_adm_opens = xrealloc(permitted_adm_opens, 3080 num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens)); 3081 permitted_adm_opens[num_adm_permitted_opens].host_to_connect 3082 = xstrdup(host); 3083 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port; 3084 return ++num_adm_permitted_opens; 3085 } 3086 3087 void 3088 channel_clear_permitted_opens(void) 3089 { 3090 int i; 3091 3092 for (i = 0; i < num_permitted_opens; i++) 3093 if (permitted_opens[i].host_to_connect != NULL) 3094 xfree(permitted_opens[i].host_to_connect); 3095 if (num_permitted_opens > 0) { 3096 xfree(permitted_opens); 3097 permitted_opens = NULL; 3098 } 3099 num_permitted_opens = 0; 3100 } 3101 3102 void 3103 channel_clear_adm_permitted_opens(void) 3104 { 3105 int i; 3106 3107 for (i = 0; i < num_adm_permitted_opens; i++) 3108 if (permitted_adm_opens[i].host_to_connect != NULL) 3109 xfree(permitted_adm_opens[i].host_to_connect); 3110 if (num_adm_permitted_opens > 0) { 3111 xfree(permitted_adm_opens); 3112 permitted_adm_opens = NULL; 3113 } 3114 num_adm_permitted_opens = 0; 3115 } 3116 3117 void 3118 channel_print_adm_permitted_opens(void) 3119 { 3120 int i; 3121 3122 printf("permitopen"); 3123 if (num_adm_permitted_opens == 0) { 3124 printf(" any\n"); 3125 return; 3126 } 3127 for (i = 0; i < num_adm_permitted_opens; i++) 3128 if (permitted_adm_opens[i].host_to_connect != NULL) 3129 printf(" %s:%d", permitted_adm_opens[i].host_to_connect, 3130 permitted_adm_opens[i].port_to_connect); 3131 printf("\n"); 3132 } 3133 3134 /* Try to start non-blocking connect to next host in cctx list */ 3135 static int 3136 connect_next(struct channel_connect *cctx) 3137 { 3138 int sock, saved_errno; 3139 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 3140 3141 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 3142 if (cctx->ai->ai_family != AF_INET && 3143 cctx->ai->ai_family != AF_INET6) 3144 continue; 3145 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 3146 ntop, sizeof(ntop), strport, sizeof(strport), 3147 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3148 error("connect_next: getnameinfo failed"); 3149 continue; 3150 } 3151 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 3152 cctx->ai->ai_protocol)) == -1) { 3153 if (cctx->ai->ai_next == NULL) 3154 error("socket: %.100s", strerror(errno)); 3155 else 3156 verbose("socket: %.100s", strerror(errno)); 3157 continue; 3158 } 3159 if (set_nonblock(sock) == -1) 3160 fatal("%s: set_nonblock(%d)", __func__, sock); 3161 if (connect(sock, cctx->ai->ai_addr, 3162 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 3163 debug("connect_next: host %.100s ([%.100s]:%s): " 3164 "%.100s", cctx->host, ntop, strport, 3165 strerror(errno)); 3166 saved_errno = errno; 3167 close(sock); 3168 errno = saved_errno; 3169 continue; /* fail -- try next */ 3170 } 3171 debug("connect_next: host %.100s ([%.100s]:%s) " 3172 "in progress, fd=%d", cctx->host, ntop, strport, sock); 3173 cctx->ai = cctx->ai->ai_next; 3174 set_nodelay(sock); 3175 return sock; 3176 } 3177 return -1; 3178 } 3179 3180 static void 3181 channel_connect_ctx_free(struct channel_connect *cctx) 3182 { 3183 xfree(cctx->host); 3184 if (cctx->aitop) 3185 freeaddrinfo(cctx->aitop); 3186 bzero(cctx, sizeof(*cctx)); 3187 cctx->host = NULL; 3188 cctx->ai = cctx->aitop = NULL; 3189 } 3190 3191 /* Return CONNECTING channel to remote host, port */ 3192 static Channel * 3193 connect_to(const char *host, u_short port, char *ctype, char *rname) 3194 { 3195 struct addrinfo hints; 3196 int gaierr; 3197 int sock = -1; 3198 char strport[NI_MAXSERV]; 3199 struct channel_connect cctx; 3200 Channel *c; 3201 3202 memset(&cctx, 0, sizeof(cctx)); 3203 memset(&hints, 0, sizeof(hints)); 3204 hints.ai_family = IPv4or6; 3205 hints.ai_socktype = SOCK_STREAM; 3206 snprintf(strport, sizeof strport, "%d", port); 3207 if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) { 3208 error("connect_to %.100s: unknown host (%s)", host, 3209 ssh_gai_strerror(gaierr)); 3210 return NULL; 3211 } 3212 3213 cctx.host = xstrdup(host); 3214 cctx.port = port; 3215 cctx.ai = cctx.aitop; 3216 3217 if ((sock = connect_next(&cctx)) == -1) { 3218 error("connect to %.100s port %d failed: %s", 3219 host, port, strerror(errno)); 3220 channel_connect_ctx_free(&cctx); 3221 return NULL; 3222 } 3223 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 3224 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 3225 c->connect_ctx = cctx; 3226 return c; 3227 } 3228 3229 Channel * 3230 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname) 3231 { 3232 int i; 3233 3234 for (i = 0; i < num_permitted_opens; i++) { 3235 if (permitted_opens[i].host_to_connect != NULL && 3236 permitted_opens[i].listen_port == listen_port) { 3237 return connect_to( 3238 permitted_opens[i].host_to_connect, 3239 permitted_opens[i].port_to_connect, ctype, rname); 3240 } 3241 } 3242 error("WARNING: Server requests forwarding for unknown listen_port %d", 3243 listen_port); 3244 return NULL; 3245 } 3246 3247 /* Check if connecting to that port is permitted and connect. */ 3248 Channel * 3249 channel_connect_to(const char *host, u_short port, char *ctype, char *rname) 3250 { 3251 int i, permit, permit_adm = 1; 3252 3253 permit = all_opens_permitted; 3254 if (!permit) { 3255 for (i = 0; i < num_permitted_opens; i++) 3256 if (permitted_opens[i].host_to_connect != NULL && 3257 permitted_opens[i].port_to_connect == port && 3258 strcmp(permitted_opens[i].host_to_connect, host) == 0) 3259 permit = 1; 3260 } 3261 3262 if (num_adm_permitted_opens > 0) { 3263 permit_adm = 0; 3264 for (i = 0; i < num_adm_permitted_opens; i++) 3265 if (permitted_adm_opens[i].host_to_connect != NULL && 3266 permitted_adm_opens[i].port_to_connect == port && 3267 strcmp(permitted_adm_opens[i].host_to_connect, host) 3268 == 0) 3269 permit_adm = 1; 3270 } 3271 3272 if (!permit || !permit_adm) { 3273 logit("Received request to connect to host %.100s port %d, " 3274 "but the request was denied.", host, port); 3275 return NULL; 3276 } 3277 return connect_to(host, port, ctype, rname); 3278 } 3279 3280 void 3281 channel_send_window_changes(void) 3282 { 3283 u_int i; 3284 struct winsize ws; 3285 3286 for (i = 0; i < channels_alloc; i++) { 3287 if (channels[i] == NULL || !channels[i]->client_tty || 3288 channels[i]->type != SSH_CHANNEL_OPEN) 3289 continue; 3290 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) 3291 continue; 3292 channel_request_start(i, "window-change", 0); 3293 packet_put_int((u_int)ws.ws_col); 3294 packet_put_int((u_int)ws.ws_row); 3295 packet_put_int((u_int)ws.ws_xpixel); 3296 packet_put_int((u_int)ws.ws_ypixel); 3297 packet_send(); 3298 } 3299 } 3300 3301 /* -- X11 forwarding */ 3302 3303 /* 3304 * Creates an internet domain socket for listening for X11 connections. 3305 * Returns 0 and a suitable display number for the DISPLAY variable 3306 * stored in display_numberp , or -1 if an error occurs. 3307 */ 3308 int 3309 x11_create_display_inet(int x11_display_offset, int x11_use_localhost, 3310 int single_connection, u_int *display_numberp, int **chanids) 3311 { 3312 Channel *nc = NULL; 3313 int display_number, sock; 3314 u_short port; 3315 struct addrinfo hints, *ai, *aitop; 3316 char strport[NI_MAXSERV]; 3317 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 3318 3319 if (chanids == NULL) 3320 return -1; 3321 3322 for (display_number = x11_display_offset; 3323 display_number < MAX_DISPLAYS; 3324 display_number++) { 3325 port = 6000 + display_number; 3326 memset(&hints, 0, sizeof(hints)); 3327 hints.ai_family = IPv4or6; 3328 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 3329 hints.ai_socktype = SOCK_STREAM; 3330 snprintf(strport, sizeof strport, "%d", port); 3331 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { 3332 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 3333 return -1; 3334 } 3335 for (ai = aitop; ai; ai = ai->ai_next) { 3336 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 3337 continue; 3338 sock = socket(ai->ai_family, ai->ai_socktype, 3339 ai->ai_protocol); 3340 if (sock < 0) { 3341 if ((errno != EINVAL) && (errno != EAFNOSUPPORT) 3342 #ifdef EPFNOSUPPORT 3343 && (errno != EPFNOSUPPORT) 3344 #endif 3345 ) { 3346 error("socket: %.100s", strerror(errno)); 3347 freeaddrinfo(aitop); 3348 return -1; 3349 } else { 3350 debug("x11_create_display_inet: Socket family %d not supported", 3351 ai->ai_family); 3352 continue; 3353 } 3354 } 3355 if (ai->ai_family == AF_INET6) 3356 sock_set_v6only(sock); 3357 if (x11_use_localhost) 3358 channel_set_reuseaddr(sock); 3359 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3360 debug2("bind port %d: %.100s", port, strerror(errno)); 3361 close(sock); 3362 3363 for (n = 0; n < num_socks; n++) { 3364 close(socks[n]); 3365 } 3366 num_socks = 0; 3367 break; 3368 } 3369 socks[num_socks++] = sock; 3370 if (num_socks == NUM_SOCKS) 3371 break; 3372 } 3373 freeaddrinfo(aitop); 3374 if (num_socks > 0) 3375 break; 3376 } 3377 if (display_number >= MAX_DISPLAYS) { 3378 error("Failed to allocate internet-domain X11 display socket."); 3379 return -1; 3380 } 3381 /* Start listening for connections on the socket. */ 3382 for (n = 0; n < num_socks; n++) { 3383 sock = socks[n]; 3384 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 3385 error("listen: %.100s", strerror(errno)); 3386 close(sock); 3387 return -1; 3388 } 3389 } 3390 3391 /* Allocate a channel for each socket. */ 3392 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 3393 for (n = 0; n < num_socks; n++) { 3394 sock = socks[n]; 3395 /* Is this really necassary? */ 3396 if (hpn_disabled) 3397 nc = channel_new("x11 listener", 3398 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 3399 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 3400 0, "X11 inet listener", 1); 3401 else 3402 nc = channel_new("x11 listener", 3403 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 3404 hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 3405 0, "X11 inet listener", 1); 3406 nc->single_connection = single_connection; 3407 (*chanids)[n] = nc->self; 3408 } 3409 (*chanids)[n] = -1; 3410 3411 /* Return the display number for the DISPLAY environment variable. */ 3412 *display_numberp = display_number; 3413 return (0); 3414 } 3415 3416 static int 3417 connect_local_xsocket_path(const char *pathname) 3418 { 3419 int sock; 3420 struct sockaddr_un addr; 3421 3422 sock = socket(AF_UNIX, SOCK_STREAM, 0); 3423 if (sock < 0) 3424 error("socket: %.100s", strerror(errno)); 3425 memset(&addr, 0, sizeof(addr)); 3426 addr.sun_family = AF_UNIX; 3427 strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); 3428 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 3429 return sock; 3430 close(sock); 3431 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 3432 return -1; 3433 } 3434 3435 static int 3436 connect_local_xsocket(u_int dnr) 3437 { 3438 char buf[1024]; 3439 snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); 3440 return connect_local_xsocket_path(buf); 3441 } 3442 3443 int 3444 x11_connect_display(void) 3445 { 3446 u_int display_number; 3447 const char *display; 3448 char buf[1024], *cp; 3449 struct addrinfo hints, *ai, *aitop; 3450 char strport[NI_MAXSERV]; 3451 int gaierr, sock = 0; 3452 3453 /* Try to open a socket for the local X server. */ 3454 display = getenv("DISPLAY"); 3455 if (!display) { 3456 error("DISPLAY not set."); 3457 return -1; 3458 } 3459 /* 3460 * Now we decode the value of the DISPLAY variable and make a 3461 * connection to the real X server. 3462 */ 3463 3464 /* Check if the display is from launchd. */ 3465 #ifdef __APPLE__ 3466 if (strncmp(display, "/tmp/launch", 11) == 0) { 3467 sock = connect_local_xsocket_path(display); 3468 if (sock < 0) 3469 return -1; 3470 3471 /* OK, we now have a connection to the display. */ 3472 return sock; 3473 } 3474 #endif 3475 /* 3476 * Check if it is a unix domain socket. Unix domain displays are in 3477 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 3478 */ 3479 if (strncmp(display, "unix:", 5) == 0 || 3480 display[0] == ':') { 3481 /* Connect to the unix domain socket. */ 3482 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) { 3483 error("Could not parse display number from DISPLAY: %.100s", 3484 display); 3485 return -1; 3486 } 3487 /* Create a socket. */ 3488 sock = connect_local_xsocket(display_number); 3489 if (sock < 0) 3490 return -1; 3491 3492 /* OK, we now have a connection to the display. */ 3493 return sock; 3494 } 3495 /* 3496 * Connect to an inet socket. The DISPLAY value is supposedly 3497 * hostname:d[.s], where hostname may also be numeric IP address. 3498 */ 3499 strlcpy(buf, display, sizeof(buf)); 3500 cp = strchr(buf, ':'); 3501 if (!cp) { 3502 error("Could not find ':' in DISPLAY: %.100s", display); 3503 return -1; 3504 } 3505 *cp = 0; 3506 /* buf now contains the host name. But first we parse the display number. */ 3507 if (sscanf(cp + 1, "%u", &display_number) != 1) { 3508 error("Could not parse display number from DISPLAY: %.100s", 3509 display); 3510 return -1; 3511 } 3512 3513 /* Look up the host address */ 3514 memset(&hints, 0, sizeof(hints)); 3515 hints.ai_family = IPv4or6; 3516 hints.ai_socktype = SOCK_STREAM; 3517 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 3518 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 3519 error("%.100s: unknown host. (%s)", buf, 3520 ssh_gai_strerror(gaierr)); 3521 return -1; 3522 } 3523 for (ai = aitop; ai; ai = ai->ai_next) { 3524 /* Create a socket. */ 3525 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 3526 if (sock < 0) { 3527 debug2("socket: %.100s", strerror(errno)); 3528 continue; 3529 } 3530 /* Connect it to the display. */ 3531 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3532 debug2("connect %.100s port %u: %.100s", buf, 3533 6000 + display_number, strerror(errno)); 3534 close(sock); 3535 continue; 3536 } 3537 /* Success */ 3538 break; 3539 } 3540 freeaddrinfo(aitop); 3541 if (!ai) { 3542 error("connect %.100s port %u: %.100s", buf, 6000 + display_number, 3543 strerror(errno)); 3544 return -1; 3545 } 3546 set_nodelay(sock); 3547 return sock; 3548 } 3549 3550 /* 3551 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains 3552 * the remote channel number. We should do whatever we want, and respond 3553 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. 3554 */ 3555 3556 /* ARGSUSED */ 3557 void 3558 x11_input_open(int type, u_int32_t seq, void *ctxt) 3559 { 3560 Channel *c = NULL; 3561 int remote_id, sock = 0; 3562 char *remote_host; 3563 3564 debug("Received X11 open request."); 3565 3566 remote_id = packet_get_int(); 3567 3568 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 3569 remote_host = packet_get_string(NULL); 3570 } else { 3571 remote_host = xstrdup("unknown (remote did not supply name)"); 3572 } 3573 packet_check_eom(); 3574 3575 /* Obtain a connection to the real X display. */ 3576 sock = x11_connect_display(); 3577 if (sock != -1) { 3578 /* Allocate a channel for this connection. */ 3579 c = channel_new("connected x11 socket", 3580 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, 3581 remote_host, 1); 3582 c->remote_id = remote_id; 3583 c->force_drain = 1; 3584 } 3585 xfree(remote_host); 3586 if (c == NULL) { 3587 /* Send refusal to the remote host. */ 3588 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3589 packet_put_int(remote_id); 3590 } else { 3591 /* Send a confirmation to the remote host. */ 3592 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 3593 packet_put_int(remote_id); 3594 packet_put_int(c->self); 3595 } 3596 packet_send(); 3597 } 3598 3599 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ 3600 /* ARGSUSED */ 3601 void 3602 deny_input_open(int type, u_int32_t seq, void *ctxt) 3603 { 3604 int rchan = packet_get_int(); 3605 3606 switch (type) { 3607 case SSH_SMSG_AGENT_OPEN: 3608 error("Warning: ssh server tried agent forwarding."); 3609 break; 3610 case SSH_SMSG_X11_OPEN: 3611 error("Warning: ssh server tried X11 forwarding."); 3612 break; 3613 default: 3614 error("deny_input_open: type %d", type); 3615 break; 3616 } 3617 error("Warning: this is probably a break-in attempt by a malicious server."); 3618 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3619 packet_put_int(rchan); 3620 packet_send(); 3621 } 3622 3623 /* 3624 * Requests forwarding of X11 connections, generates fake authentication 3625 * data, and enables authentication spoofing. 3626 * This should be called in the client only. 3627 */ 3628 void 3629 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp, 3630 const char *proto, const char *data) 3631 { 3632 u_int data_len = (u_int) strlen(data) / 2; 3633 u_int i, value; 3634 char *new_data; 3635 int screen_number; 3636 const char *cp; 3637 u_int32_t rnd = 0; 3638 3639 if (x11_saved_display == NULL) 3640 x11_saved_display = xstrdup(disp); 3641 else if (strcmp(disp, x11_saved_display) != 0) { 3642 error("x11_request_forwarding_with_spoofing: different " 3643 "$DISPLAY already forwarded"); 3644 return; 3645 } 3646 3647 cp = strchr(disp, ':'); 3648 if (cp) 3649 cp = strchr(cp, '.'); 3650 if (cp) 3651 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 3652 else 3653 screen_number = 0; 3654 3655 if (x11_saved_proto == NULL) { 3656 /* Save protocol name. */ 3657 x11_saved_proto = xstrdup(proto); 3658 /* 3659 * Extract real authentication data and generate fake data 3660 * of the same length. 3661 */ 3662 x11_saved_data = xmalloc(data_len); 3663 x11_fake_data = xmalloc(data_len); 3664 for (i = 0; i < data_len; i++) { 3665 if (sscanf(data + 2 * i, "%2x", &value) != 1) 3666 fatal("x11_request_forwarding: bad " 3667 "authentication data: %.100s", data); 3668 if (i % 4 == 0) 3669 rnd = arc4random(); 3670 x11_saved_data[i] = value; 3671 x11_fake_data[i] = rnd & 0xff; 3672 rnd >>= 8; 3673 } 3674 x11_saved_data_len = data_len; 3675 x11_fake_data_len = data_len; 3676 } 3677 3678 /* Convert the fake data into hex. */ 3679 new_data = tohex(x11_fake_data, data_len); 3680 3681 /* Send the request packet. */ 3682 if (compat20) { 3683 channel_request_start(client_session_id, "x11-req", 0); 3684 packet_put_char(0); /* XXX bool single connection */ 3685 } else { 3686 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); 3687 } 3688 packet_put_cstring(proto); 3689 packet_put_cstring(new_data); 3690 packet_put_int(screen_number); 3691 packet_send(); 3692 packet_write_wait(); 3693 xfree(new_data); 3694 } 3695 3696 3697 /* -- agent forwarding */ 3698 3699 /* Sends a message to the server to request authentication fd forwarding. */ 3700 3701 void 3702 auth_request_forwarding(void) 3703 { 3704 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); 3705 packet_send(); 3706 packet_write_wait(); 3707 } 3708