1 /* 2 * Author: Tatu Ylonen <ylo@cs.hut.fi> 3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4 * All rights reserved 5 * This file contains functions for generic socket connection forwarding. 6 * There is also code for initiating connection forwarding for X11 connections, 7 * arbitrary tcp/ip connections, and the authentication agent connection. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * SSH2 support added by Markus Friedl. 16 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 17 * Copyright (c) 1999 Dug Song. All rights reserved. 18 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 19 * 20 * Redistribution and use in source and binary forms, with or without 21 * modification, are permitted provided that the following conditions 22 * are met: 23 * 1. Redistributions of source code must retain the above copyright 24 * notice, this list of conditions and the following disclaimer. 25 * 2. Redistributions in binary form must reproduce the above copyright 26 * notice, this list of conditions and the following disclaimer in the 27 * documentation and/or other materials provided with the distribution. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 30 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 31 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 32 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 33 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 34 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 38 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 */ 40 41 #include "includes.h" 42 RCSID("$OpenBSD: channels.c,v 1.232 2006/01/30 12:22:22 reyk Exp $"); 43 44 #include "ssh.h" 45 #include "ssh1.h" 46 #include "ssh2.h" 47 #include "packet.h" 48 #include "xmalloc.h" 49 #include "log.h" 50 #include "misc.h" 51 #include "channels.h" 52 #include "compat.h" 53 #include "canohost.h" 54 #include "key.h" 55 #include "authfd.h" 56 #include "pathnames.h" 57 #include "bufaux.h" 58 59 /* -- channel core */ 60 61 /* 62 * Pointer to an array containing all allocated channels. The array is 63 * dynamically extended as needed. 64 */ 65 static Channel **channels = NULL; 66 67 /* 68 * Size of the channel array. All slots of the array must always be 69 * initialized (at least the type field); unused slots set to NULL 70 */ 71 static u_int channels_alloc = 0; 72 73 /* 74 * Maximum file descriptor value used in any of the channels. This is 75 * updated in channel_new. 76 */ 77 static int channel_max_fd = 0; 78 79 80 /* -- tcp forwarding */ 81 82 /* 83 * Data structure for storing which hosts are permitted for forward requests. 84 * The local sides of any remote forwards are stored in this array to prevent 85 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 86 * network (which might be behind a firewall). 87 */ 88 typedef struct { 89 char *host_to_connect; /* Connect to 'host'. */ 90 u_short port_to_connect; /* Connect to 'port'. */ 91 u_short listen_port; /* Remote side should listen port number. */ 92 } ForwardPermission; 93 94 /* List of all permitted host/port pairs to connect. */ 95 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; 96 97 /* Number of permitted host/port pairs in the array. */ 98 static int num_permitted_opens = 0; 99 /* 100 * If this is true, all opens are permitted. This is the case on the server 101 * on which we have to trust the client anyway, and the user could do 102 * anything after logging in anyway. 103 */ 104 static int all_opens_permitted = 0; 105 106 107 /* -- X11 forwarding */ 108 109 /* Maximum number of fake X11 displays to try. */ 110 #define MAX_DISPLAYS 1000 111 112 /* Saved X11 local (client) display. */ 113 static char *x11_saved_display = NULL; 114 115 /* Saved X11 authentication protocol name. */ 116 static char *x11_saved_proto = NULL; 117 118 /* Saved X11 authentication data. This is the real data. */ 119 static char *x11_saved_data = NULL; 120 static u_int x11_saved_data_len = 0; 121 122 /* 123 * Fake X11 authentication data. This is what the server will be sending us; 124 * we should replace any occurrences of this by the real data. 125 */ 126 static char *x11_fake_data = NULL; 127 static u_int x11_fake_data_len; 128 129 130 /* -- agent forwarding */ 131 132 #define NUM_SOCKS 10 133 134 /* AF_UNSPEC or AF_INET or AF_INET6 */ 135 static int IPv4or6 = AF_UNSPEC; 136 137 /* helper */ 138 static void port_open_helper(Channel *c, char *rtype); 139 140 /* -- channel core */ 141 142 Channel * 143 channel_by_id(int id) 144 { 145 Channel *c; 146 147 if (id < 0 || (u_int)id >= channels_alloc) { 148 logit("channel_by_id: %d: bad id", id); 149 return NULL; 150 } 151 c = channels[id]; 152 if (c == NULL) { 153 logit("channel_by_id: %d: bad id: channel free", id); 154 return NULL; 155 } 156 return c; 157 } 158 159 /* 160 * Returns the channel if it is allowed to receive protocol messages. 161 * Private channels, like listening sockets, may not receive messages. 162 */ 163 Channel * 164 channel_lookup(int id) 165 { 166 Channel *c; 167 168 if ((c = channel_by_id(id)) == NULL) 169 return (NULL); 170 171 switch(c->type) { 172 case SSH_CHANNEL_X11_OPEN: 173 case SSH_CHANNEL_LARVAL: 174 case SSH_CHANNEL_CONNECTING: 175 case SSH_CHANNEL_DYNAMIC: 176 case SSH_CHANNEL_OPENING: 177 case SSH_CHANNEL_OPEN: 178 case SSH_CHANNEL_INPUT_DRAINING: 179 case SSH_CHANNEL_OUTPUT_DRAINING: 180 return (c); 181 break; 182 } 183 logit("Non-public channel %d, type %d.", id, c->type); 184 return (NULL); 185 } 186 187 /* 188 * Register filedescriptors for a channel, used when allocating a channel or 189 * when the channel consumer/producer is ready, e.g. shell exec'd 190 */ 191 192 static void 193 channel_register_fds(Channel *c, int rfd, int wfd, int efd, 194 int extusage, int nonblock) 195 { 196 /* Update the maximum file descriptor value. */ 197 channel_max_fd = MAX(channel_max_fd, rfd); 198 channel_max_fd = MAX(channel_max_fd, wfd); 199 channel_max_fd = MAX(channel_max_fd, efd); 200 201 /* XXX set close-on-exec -markus */ 202 203 c->rfd = rfd; 204 c->wfd = wfd; 205 c->sock = (rfd == wfd) ? rfd : -1; 206 c->ctl_fd = -1; /* XXX: set elsewhere */ 207 c->efd = efd; 208 c->extended_usage = extusage; 209 210 /* XXX ugly hack: nonblock is only set by the server */ 211 if (nonblock && isatty(c->rfd)) { 212 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 213 c->isatty = 1; 214 if (!isatty(c->wfd)) { 215 error("channel %d: wfd %d is not a tty?", 216 c->self, c->wfd); 217 } 218 } else { 219 c->isatty = 0; 220 } 221 c->wfd_isatty = isatty(c->wfd); 222 223 /* enable nonblocking mode */ 224 if (nonblock) { 225 if (rfd != -1) 226 set_nonblock(rfd); 227 if (wfd != -1) 228 set_nonblock(wfd); 229 if (efd != -1) 230 set_nonblock(efd); 231 } 232 } 233 234 /* 235 * Allocate a new channel object and set its type and socket. This will cause 236 * remote_name to be freed. 237 */ 238 239 Channel * 240 channel_new(char *ctype, int type, int rfd, int wfd, int efd, 241 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) 242 { 243 int found; 244 u_int i; 245 Channel *c; 246 247 /* Do initial allocation if this is the first call. */ 248 if (channels_alloc == 0) { 249 channels_alloc = 10; 250 channels = xmalloc(channels_alloc * sizeof(Channel *)); 251 for (i = 0; i < channels_alloc; i++) 252 channels[i] = NULL; 253 } 254 /* Try to find a free slot where to put the new channel. */ 255 for (found = -1, i = 0; i < channels_alloc; i++) 256 if (channels[i] == NULL) { 257 /* Found a free slot. */ 258 found = (int)i; 259 break; 260 } 261 if (found < 0) { 262 /* There are no free slots. Take last+1 slot and expand the array. */ 263 found = channels_alloc; 264 if (channels_alloc > 10000) 265 fatal("channel_new: internal error: channels_alloc %d " 266 "too big.", channels_alloc); 267 channels = xrealloc(channels, 268 (channels_alloc + 10) * sizeof(Channel *)); 269 channels_alloc += 10; 270 debug2("channel: expanding %d", channels_alloc); 271 for (i = found; i < channels_alloc; i++) 272 channels[i] = NULL; 273 } 274 /* Initialize and return new channel. */ 275 c = channels[found] = xmalloc(sizeof(Channel)); 276 memset(c, 0, sizeof(Channel)); 277 buffer_init(&c->input); 278 buffer_init(&c->output); 279 buffer_init(&c->extended); 280 c->ostate = CHAN_OUTPUT_OPEN; 281 c->istate = CHAN_INPUT_OPEN; 282 c->flags = 0; 283 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); 284 c->self = found; 285 c->type = type; 286 c->ctype = ctype; 287 c->local_window = window; 288 c->local_window_max = window; 289 c->local_consumed = 0; 290 c->local_maxpacket = maxpack; 291 c->remote_id = -1; 292 c->remote_name = xstrdup(remote_name); 293 c->remote_window = 0; 294 c->remote_maxpacket = 0; 295 c->force_drain = 0; 296 c->single_connection = 0; 297 c->detach_user = NULL; 298 c->detach_close = 0; 299 c->confirm = NULL; 300 c->confirm_ctx = NULL; 301 c->input_filter = NULL; 302 c->output_filter = NULL; 303 debug("channel %d: new [%s]", found, remote_name); 304 return c; 305 } 306 307 static int 308 channel_find_maxfd(void) 309 { 310 u_int i; 311 int max = 0; 312 Channel *c; 313 314 for (i = 0; i < channels_alloc; i++) { 315 c = channels[i]; 316 if (c != NULL) { 317 max = MAX(max, c->rfd); 318 max = MAX(max, c->wfd); 319 max = MAX(max, c->efd); 320 } 321 } 322 return max; 323 } 324 325 int 326 channel_close_fd(int *fdp) 327 { 328 int ret = 0, fd = *fdp; 329 330 if (fd != -1) { 331 ret = close(fd); 332 *fdp = -1; 333 if (fd == channel_max_fd) 334 channel_max_fd = channel_find_maxfd(); 335 } 336 return ret; 337 } 338 339 /* Close all channel fd/socket. */ 340 341 static void 342 channel_close_fds(Channel *c) 343 { 344 debug3("channel %d: close_fds r %d w %d e %d c %d", 345 c->self, c->rfd, c->wfd, c->efd, c->ctl_fd); 346 347 channel_close_fd(&c->sock); 348 channel_close_fd(&c->ctl_fd); 349 channel_close_fd(&c->rfd); 350 channel_close_fd(&c->wfd); 351 channel_close_fd(&c->efd); 352 } 353 354 /* Free the channel and close its fd/socket. */ 355 356 void 357 channel_free(Channel *c) 358 { 359 char *s; 360 u_int i, n; 361 362 for (n = 0, i = 0; i < channels_alloc; i++) 363 if (channels[i]) 364 n++; 365 debug("channel %d: free: %s, nchannels %u", c->self, 366 c->remote_name ? c->remote_name : "???", n); 367 368 s = channel_open_message(); 369 debug3("channel %d: status: %s", c->self, s); 370 xfree(s); 371 372 if (c->sock != -1) 373 shutdown(c->sock, SHUT_RDWR); 374 if (c->ctl_fd != -1) 375 shutdown(c->ctl_fd, SHUT_RDWR); 376 channel_close_fds(c); 377 buffer_free(&c->input); 378 buffer_free(&c->output); 379 buffer_free(&c->extended); 380 if (c->remote_name) { 381 xfree(c->remote_name); 382 c->remote_name = NULL; 383 } 384 channels[c->self] = NULL; 385 xfree(c); 386 } 387 388 void 389 channel_free_all(void) 390 { 391 u_int i; 392 393 for (i = 0; i < channels_alloc; i++) 394 if (channels[i] != NULL) 395 channel_free(channels[i]); 396 } 397 398 /* 399 * Closes the sockets/fds of all channels. This is used to close extra file 400 * descriptors after a fork. 401 */ 402 403 void 404 channel_close_all(void) 405 { 406 u_int i; 407 408 for (i = 0; i < channels_alloc; i++) 409 if (channels[i] != NULL) 410 channel_close_fds(channels[i]); 411 } 412 413 /* 414 * Stop listening to channels. 415 */ 416 417 void 418 channel_stop_listening(void) 419 { 420 u_int i; 421 Channel *c; 422 423 for (i = 0; i < channels_alloc; i++) { 424 c = channels[i]; 425 if (c != NULL) { 426 switch (c->type) { 427 case SSH_CHANNEL_AUTH_SOCKET: 428 case SSH_CHANNEL_PORT_LISTENER: 429 case SSH_CHANNEL_RPORT_LISTENER: 430 case SSH_CHANNEL_X11_LISTENER: 431 channel_close_fd(&c->sock); 432 channel_free(c); 433 break; 434 } 435 } 436 } 437 } 438 439 /* 440 * Returns true if no channel has too much buffered data, and false if one or 441 * more channel is overfull. 442 */ 443 444 int 445 channel_not_very_much_buffered_data(void) 446 { 447 u_int i; 448 Channel *c; 449 450 for (i = 0; i < channels_alloc; i++) { 451 c = channels[i]; 452 if (c != NULL && c->type == SSH_CHANNEL_OPEN) { 453 #if 0 454 if (!compat20 && 455 buffer_len(&c->input) > packet_get_maxsize()) { 456 debug2("channel %d: big input buffer %d", 457 c->self, buffer_len(&c->input)); 458 return 0; 459 } 460 #endif 461 if (buffer_len(&c->output) > packet_get_maxsize()) { 462 debug2("channel %d: big output buffer %u > %u", 463 c->self, buffer_len(&c->output), 464 packet_get_maxsize()); 465 return 0; 466 } 467 } 468 } 469 return 1; 470 } 471 472 /* Returns true if any channel is still open. */ 473 474 int 475 channel_still_open(void) 476 { 477 u_int i; 478 Channel *c; 479 480 for (i = 0; i < channels_alloc; i++) { 481 c = channels[i]; 482 if (c == NULL) 483 continue; 484 switch (c->type) { 485 case SSH_CHANNEL_X11_LISTENER: 486 case SSH_CHANNEL_PORT_LISTENER: 487 case SSH_CHANNEL_RPORT_LISTENER: 488 case SSH_CHANNEL_CLOSED: 489 case SSH_CHANNEL_AUTH_SOCKET: 490 case SSH_CHANNEL_DYNAMIC: 491 case SSH_CHANNEL_CONNECTING: 492 case SSH_CHANNEL_ZOMBIE: 493 continue; 494 case SSH_CHANNEL_LARVAL: 495 if (!compat20) 496 fatal("cannot happen: SSH_CHANNEL_LARVAL"); 497 continue; 498 case SSH_CHANNEL_OPENING: 499 case SSH_CHANNEL_OPEN: 500 case SSH_CHANNEL_X11_OPEN: 501 return 1; 502 case SSH_CHANNEL_INPUT_DRAINING: 503 case SSH_CHANNEL_OUTPUT_DRAINING: 504 if (!compat13) 505 fatal("cannot happen: OUT_DRAIN"); 506 return 1; 507 default: 508 fatal("channel_still_open: bad channel type %d", c->type); 509 /* NOTREACHED */ 510 } 511 } 512 return 0; 513 } 514 515 /* Returns the id of an open channel suitable for keepaliving */ 516 517 int 518 channel_find_open(void) 519 { 520 u_int i; 521 Channel *c; 522 523 for (i = 0; i < channels_alloc; i++) { 524 c = channels[i]; 525 if (c == NULL || c->remote_id < 0) 526 continue; 527 switch (c->type) { 528 case SSH_CHANNEL_CLOSED: 529 case SSH_CHANNEL_DYNAMIC: 530 case SSH_CHANNEL_X11_LISTENER: 531 case SSH_CHANNEL_PORT_LISTENER: 532 case SSH_CHANNEL_RPORT_LISTENER: 533 case SSH_CHANNEL_OPENING: 534 case SSH_CHANNEL_CONNECTING: 535 case SSH_CHANNEL_ZOMBIE: 536 continue; 537 case SSH_CHANNEL_LARVAL: 538 case SSH_CHANNEL_AUTH_SOCKET: 539 case SSH_CHANNEL_OPEN: 540 case SSH_CHANNEL_X11_OPEN: 541 return i; 542 case SSH_CHANNEL_INPUT_DRAINING: 543 case SSH_CHANNEL_OUTPUT_DRAINING: 544 if (!compat13) 545 fatal("cannot happen: OUT_DRAIN"); 546 return i; 547 default: 548 fatal("channel_find_open: bad channel type %d", c->type); 549 /* NOTREACHED */ 550 } 551 } 552 return -1; 553 } 554 555 556 /* 557 * Returns a message describing the currently open forwarded connections, 558 * suitable for sending to the client. The message contains crlf pairs for 559 * newlines. 560 */ 561 562 char * 563 channel_open_message(void) 564 { 565 Buffer buffer; 566 Channel *c; 567 char buf[1024], *cp; 568 u_int i; 569 570 buffer_init(&buffer); 571 snprintf(buf, sizeof buf, "The following connections are open:\r\n"); 572 buffer_append(&buffer, buf, strlen(buf)); 573 for (i = 0; i < channels_alloc; i++) { 574 c = channels[i]; 575 if (c == NULL) 576 continue; 577 switch (c->type) { 578 case SSH_CHANNEL_X11_LISTENER: 579 case SSH_CHANNEL_PORT_LISTENER: 580 case SSH_CHANNEL_RPORT_LISTENER: 581 case SSH_CHANNEL_CLOSED: 582 case SSH_CHANNEL_AUTH_SOCKET: 583 case SSH_CHANNEL_ZOMBIE: 584 continue; 585 case SSH_CHANNEL_LARVAL: 586 case SSH_CHANNEL_OPENING: 587 case SSH_CHANNEL_CONNECTING: 588 case SSH_CHANNEL_DYNAMIC: 589 case SSH_CHANNEL_OPEN: 590 case SSH_CHANNEL_X11_OPEN: 591 case SSH_CHANNEL_INPUT_DRAINING: 592 case SSH_CHANNEL_OUTPUT_DRAINING: 593 snprintf(buf, sizeof buf, 594 " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n", 595 c->self, c->remote_name, 596 c->type, c->remote_id, 597 c->istate, buffer_len(&c->input), 598 c->ostate, buffer_len(&c->output), 599 c->rfd, c->wfd, c->ctl_fd); 600 buffer_append(&buffer, buf, strlen(buf)); 601 continue; 602 default: 603 fatal("channel_open_message: bad channel type %d", c->type); 604 /* NOTREACHED */ 605 } 606 } 607 buffer_append(&buffer, "\0", 1); 608 cp = xstrdup(buffer_ptr(&buffer)); 609 buffer_free(&buffer); 610 return cp; 611 } 612 613 void 614 channel_send_open(int id) 615 { 616 Channel *c = channel_lookup(id); 617 618 if (c == NULL) { 619 logit("channel_send_open: %d: bad id", id); 620 return; 621 } 622 debug2("channel %d: send open", id); 623 packet_start(SSH2_MSG_CHANNEL_OPEN); 624 packet_put_cstring(c->ctype); 625 packet_put_int(c->self); 626 packet_put_int(c->local_window); 627 packet_put_int(c->local_maxpacket); 628 packet_send(); 629 } 630 631 void 632 channel_request_start(int id, char *service, int wantconfirm) 633 { 634 Channel *c = channel_lookup(id); 635 636 if (c == NULL) { 637 logit("channel_request_start: %d: unknown channel id", id); 638 return; 639 } 640 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 641 packet_start(SSH2_MSG_CHANNEL_REQUEST); 642 packet_put_int(c->remote_id); 643 packet_put_cstring(service); 644 packet_put_char(wantconfirm); 645 } 646 void 647 channel_register_confirm(int id, channel_callback_fn *fn, void *ctx) 648 { 649 Channel *c = channel_lookup(id); 650 651 if (c == NULL) { 652 logit("channel_register_comfirm: %d: bad id", id); 653 return; 654 } 655 c->confirm = fn; 656 c->confirm_ctx = ctx; 657 } 658 void 659 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close) 660 { 661 Channel *c = channel_by_id(id); 662 663 if (c == NULL) { 664 logit("channel_register_cleanup: %d: bad id", id); 665 return; 666 } 667 c->detach_user = fn; 668 c->detach_close = do_close; 669 } 670 void 671 channel_cancel_cleanup(int id) 672 { 673 Channel *c = channel_by_id(id); 674 675 if (c == NULL) { 676 logit("channel_cancel_cleanup: %d: bad id", id); 677 return; 678 } 679 c->detach_user = NULL; 680 c->detach_close = 0; 681 } 682 void 683 channel_register_filter(int id, channel_infilter_fn *ifn, 684 channel_outfilter_fn *ofn) 685 { 686 Channel *c = channel_lookup(id); 687 688 if (c == NULL) { 689 logit("channel_register_filter: %d: bad id", id); 690 return; 691 } 692 c->input_filter = ifn; 693 c->output_filter = ofn; 694 } 695 696 void 697 channel_set_fds(int id, int rfd, int wfd, int efd, 698 int extusage, int nonblock, u_int window_max) 699 { 700 Channel *c = channel_lookup(id); 701 702 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 703 fatal("channel_activate for non-larval channel %d.", id); 704 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); 705 c->type = SSH_CHANNEL_OPEN; 706 c->local_window = c->local_window_max = window_max; 707 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 708 packet_put_int(c->remote_id); 709 packet_put_int(c->local_window); 710 packet_send(); 711 } 712 713 /* 714 * 'channel_pre*' are called just before select() to add any bits relevant to 715 * channels in the select bitmasks. 716 */ 717 /* 718 * 'channel_post*': perform any appropriate operations for channels which 719 * have events pending. 720 */ 721 typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset); 722 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; 723 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; 724 725 static void 726 channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset) 727 { 728 FD_SET(c->sock, readset); 729 } 730 731 static void 732 channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset) 733 { 734 debug3("channel %d: waiting for connection", c->self); 735 FD_SET(c->sock, writeset); 736 } 737 738 static void 739 channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset) 740 { 741 if (buffer_len(&c->input) < packet_get_maxsize()) 742 FD_SET(c->sock, readset); 743 if (buffer_len(&c->output) > 0) 744 FD_SET(c->sock, writeset); 745 } 746 747 static void 748 channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset) 749 { 750 u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); 751 752 /* check buffer limits */ 753 limit = MIN(limit, (BUFFER_MAX_LEN - BUFFER_MAX_CHUNK - CHAN_RBUF)); 754 755 if (c->istate == CHAN_INPUT_OPEN && 756 limit > 0 && 757 buffer_len(&c->input) < limit) 758 FD_SET(c->rfd, readset); 759 if (c->ostate == CHAN_OUTPUT_OPEN || 760 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 761 if (buffer_len(&c->output) > 0) { 762 FD_SET(c->wfd, writeset); 763 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 764 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 765 debug2("channel %d: obuf_empty delayed efd %d/(%d)", 766 c->self, c->efd, buffer_len(&c->extended)); 767 else 768 chan_obuf_empty(c); 769 } 770 } 771 /** XXX check close conditions, too */ 772 if (compat20 && c->efd != -1) { 773 if (c->extended_usage == CHAN_EXTENDED_WRITE && 774 buffer_len(&c->extended) > 0) 775 FD_SET(c->efd, writeset); 776 else if (!(c->flags & CHAN_EOF_SENT) && 777 c->extended_usage == CHAN_EXTENDED_READ && 778 buffer_len(&c->extended) < c->remote_window) 779 FD_SET(c->efd, readset); 780 } 781 /* XXX: What about efd? races? */ 782 if (compat20 && c->ctl_fd != -1 && 783 c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN) 784 FD_SET(c->ctl_fd, readset); 785 } 786 787 static void 788 channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset) 789 { 790 if (buffer_len(&c->input) == 0) { 791 packet_start(SSH_MSG_CHANNEL_CLOSE); 792 packet_put_int(c->remote_id); 793 packet_send(); 794 c->type = SSH_CHANNEL_CLOSED; 795 debug2("channel %d: closing after input drain.", c->self); 796 } 797 } 798 799 static void 800 channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset) 801 { 802 if (buffer_len(&c->output) == 0) 803 chan_mark_dead(c); 804 else 805 FD_SET(c->sock, writeset); 806 } 807 808 /* 809 * This is a special state for X11 authentication spoofing. An opened X11 810 * connection (when authentication spoofing is being done) remains in this 811 * state until the first packet has been completely read. The authentication 812 * data in that packet is then substituted by the real data if it matches the 813 * fake data, and the channel is put into normal mode. 814 * XXX All this happens at the client side. 815 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 816 */ 817 static int 818 x11_open_helper(Buffer *b) 819 { 820 u_char *ucp; 821 u_int proto_len, data_len; 822 823 /* Check if the fixed size part of the packet is in buffer. */ 824 if (buffer_len(b) < 12) 825 return 0; 826 827 /* Parse the lengths of variable-length fields. */ 828 ucp = buffer_ptr(b); 829 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 830 proto_len = 256 * ucp[6] + ucp[7]; 831 data_len = 256 * ucp[8] + ucp[9]; 832 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 833 proto_len = ucp[6] + 256 * ucp[7]; 834 data_len = ucp[8] + 256 * ucp[9]; 835 } else { 836 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 837 ucp[0]); 838 return -1; 839 } 840 841 /* Check if the whole packet is in buffer. */ 842 if (buffer_len(b) < 843 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 844 return 0; 845 846 /* Check if authentication protocol matches. */ 847 if (proto_len != strlen(x11_saved_proto) || 848 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { 849 debug2("X11 connection uses different authentication protocol."); 850 return -1; 851 } 852 /* Check if authentication data matches our fake data. */ 853 if (data_len != x11_fake_data_len || 854 memcmp(ucp + 12 + ((proto_len + 3) & ~3), 855 x11_fake_data, x11_fake_data_len) != 0) { 856 debug2("X11 auth data does not match fake data."); 857 return -1; 858 } 859 /* Check fake data length */ 860 if (x11_fake_data_len != x11_saved_data_len) { 861 error("X11 fake_data_len %d != saved_data_len %d", 862 x11_fake_data_len, x11_saved_data_len); 863 return -1; 864 } 865 /* 866 * Received authentication protocol and data match 867 * our fake data. Substitute the fake data with real 868 * data. 869 */ 870 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 871 x11_saved_data, x11_saved_data_len); 872 return 1; 873 } 874 875 static void 876 channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset) 877 { 878 int ret = x11_open_helper(&c->output); 879 880 if (ret == 1) { 881 /* Start normal processing for the channel. */ 882 c->type = SSH_CHANNEL_OPEN; 883 channel_pre_open_13(c, readset, writeset); 884 } else if (ret == -1) { 885 /* 886 * We have received an X11 connection that has bad 887 * authentication information. 888 */ 889 logit("X11 connection rejected because of wrong authentication."); 890 buffer_clear(&c->input); 891 buffer_clear(&c->output); 892 channel_close_fd(&c->sock); 893 c->sock = -1; 894 c->type = SSH_CHANNEL_CLOSED; 895 packet_start(SSH_MSG_CHANNEL_CLOSE); 896 packet_put_int(c->remote_id); 897 packet_send(); 898 } 899 } 900 901 static void 902 channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset) 903 { 904 int ret = x11_open_helper(&c->output); 905 906 /* c->force_drain = 1; */ 907 908 if (ret == 1) { 909 c->type = SSH_CHANNEL_OPEN; 910 channel_pre_open(c, readset, writeset); 911 } else if (ret == -1) { 912 logit("X11 connection rejected because of wrong authentication."); 913 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); 914 chan_read_failed(c); 915 buffer_clear(&c->input); 916 chan_ibuf_empty(c); 917 buffer_clear(&c->output); 918 /* for proto v1, the peer will send an IEOF */ 919 if (compat20) 920 chan_write_failed(c); 921 else 922 c->type = SSH_CHANNEL_OPEN; 923 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 924 } 925 } 926 927 /* try to decode a socks4 header */ 928 static int 929 channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset) 930 { 931 char *p, *host; 932 u_int len, have, i, found; 933 char username[256]; 934 struct { 935 u_int8_t version; 936 u_int8_t command; 937 u_int16_t dest_port; 938 struct in_addr dest_addr; 939 } s4_req, s4_rsp; 940 941 debug2("channel %d: decode socks4", c->self); 942 943 have = buffer_len(&c->input); 944 len = sizeof(s4_req); 945 if (have < len) 946 return 0; 947 p = buffer_ptr(&c->input); 948 for (found = 0, i = len; i < have; i++) { 949 if (p[i] == '\0') { 950 found = 1; 951 break; 952 } 953 if (i > 1024) { 954 /* the peer is probably sending garbage */ 955 debug("channel %d: decode socks4: too long", 956 c->self); 957 return -1; 958 } 959 } 960 if (!found) 961 return 0; 962 buffer_get(&c->input, (char *)&s4_req.version, 1); 963 buffer_get(&c->input, (char *)&s4_req.command, 1); 964 buffer_get(&c->input, (char *)&s4_req.dest_port, 2); 965 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); 966 have = buffer_len(&c->input); 967 p = buffer_ptr(&c->input); 968 len = strlen(p); 969 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 970 if (len > have) 971 fatal("channel %d: decode socks4: len %d > have %d", 972 c->self, len, have); 973 strlcpy(username, p, sizeof(username)); 974 buffer_consume(&c->input, len); 975 buffer_consume(&c->input, 1); /* trailing '\0' */ 976 977 host = inet_ntoa(s4_req.dest_addr); 978 strlcpy(c->path, host, sizeof(c->path)); 979 c->host_port = ntohs(s4_req.dest_port); 980 981 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 982 c->self, host, c->host_port, s4_req.command); 983 984 if (s4_req.command != 1) { 985 debug("channel %d: cannot handle: socks4 cn %d", 986 c->self, s4_req.command); 987 return -1; 988 } 989 s4_rsp.version = 0; /* vn: 0 for reply */ 990 s4_rsp.command = 90; /* cd: req granted */ 991 s4_rsp.dest_port = 0; /* ignored */ 992 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 993 buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp)); 994 return 1; 995 } 996 997 /* try to decode a socks5 header */ 998 #define SSH_SOCKS5_AUTHDONE 0x1000 999 #define SSH_SOCKS5_NOAUTH 0x00 1000 #define SSH_SOCKS5_IPV4 0x01 1001 #define SSH_SOCKS5_DOMAIN 0x03 1002 #define SSH_SOCKS5_IPV6 0x04 1003 #define SSH_SOCKS5_CONNECT 0x01 1004 #define SSH_SOCKS5_SUCCESS 0x00 1005 1006 static int 1007 channel_decode_socks5(Channel *c, fd_set * readset, fd_set * writeset) 1008 { 1009 struct { 1010 u_int8_t version; 1011 u_int8_t command; 1012 u_int8_t reserved; 1013 u_int8_t atyp; 1014 } s5_req, s5_rsp; 1015 u_int16_t dest_port; 1016 u_char *p, dest_addr[255+1]; 1017 u_int have, i, found, nmethods, addrlen, af; 1018 1019 debug2("channel %d: decode socks5", c->self); 1020 p = buffer_ptr(&c->input); 1021 if (p[0] != 0x05) 1022 return -1; 1023 have = buffer_len(&c->input); 1024 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1025 /* format: ver | nmethods | methods */ 1026 if (have < 2) 1027 return 0; 1028 nmethods = p[1]; 1029 if (have < nmethods + 2) 1030 return 0; 1031 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1032 for (found = 0, i = 2 ; i < nmethods + 2; i++) { 1033 if (p[i] == SSH_SOCKS5_NOAUTH ) { 1034 found = 1; 1035 break; 1036 } 1037 } 1038 if (!found) { 1039 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1040 c->self); 1041 return -1; 1042 } 1043 buffer_consume(&c->input, nmethods + 2); 1044 buffer_put_char(&c->output, 0x05); /* version */ 1045 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ 1046 FD_SET(c->sock, writeset); 1047 c->flags |= SSH_SOCKS5_AUTHDONE; 1048 debug2("channel %d: socks5 auth done", c->self); 1049 return 0; /* need more */ 1050 } 1051 debug2("channel %d: socks5 post auth", c->self); 1052 if (have < sizeof(s5_req)+1) 1053 return 0; /* need more */ 1054 memcpy((char *)&s5_req, p, sizeof(s5_req)); 1055 if (s5_req.version != 0x05 || 1056 s5_req.command != SSH_SOCKS5_CONNECT || 1057 s5_req.reserved != 0x00) { 1058 debug2("channel %d: only socks5 connect supported", c->self); 1059 return -1; 1060 } 1061 switch (s5_req.atyp){ 1062 case SSH_SOCKS5_IPV4: 1063 addrlen = 4; 1064 af = AF_INET; 1065 break; 1066 case SSH_SOCKS5_DOMAIN: 1067 addrlen = p[sizeof(s5_req)]; 1068 af = -1; 1069 break; 1070 case SSH_SOCKS5_IPV6: 1071 addrlen = 16; 1072 af = AF_INET6; 1073 break; 1074 default: 1075 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1076 return -1; 1077 } 1078 if (have < 4 + addrlen + 2) 1079 return 0; 1080 buffer_consume(&c->input, sizeof(s5_req)); 1081 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1082 buffer_consume(&c->input, 1); /* host string length */ 1083 buffer_get(&c->input, (char *)&dest_addr, addrlen); 1084 buffer_get(&c->input, (char *)&dest_port, 2); 1085 dest_addr[addrlen] = '\0'; 1086 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1087 strlcpy(c->path, (char *)dest_addr, sizeof(c->path)); 1088 else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL) 1089 return -1; 1090 c->host_port = ntohs(dest_port); 1091 1092 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1093 c->self, c->path, c->host_port, s5_req.command); 1094 1095 s5_rsp.version = 0x05; 1096 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1097 s5_rsp.reserved = 0; /* ignored */ 1098 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1099 ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY; 1100 dest_port = 0; /* ignored */ 1101 1102 buffer_append(&c->output, (char *)&s5_rsp, sizeof(s5_rsp)); 1103 buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr)); 1104 buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port)); 1105 return 1; 1106 } 1107 1108 /* dynamic port forwarding */ 1109 static void 1110 channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset) 1111 { 1112 u_char *p; 1113 u_int have; 1114 int ret; 1115 1116 have = buffer_len(&c->input); 1117 c->delayed = 0; 1118 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1119 /* buffer_dump(&c->input); */ 1120 /* check if the fixed size part of the packet is in buffer. */ 1121 if (have < 3) { 1122 /* need more */ 1123 FD_SET(c->sock, readset); 1124 return; 1125 } 1126 /* try to guess the protocol */ 1127 p = buffer_ptr(&c->input); 1128 switch (p[0]) { 1129 case 0x04: 1130 ret = channel_decode_socks4(c, readset, writeset); 1131 break; 1132 case 0x05: 1133 ret = channel_decode_socks5(c, readset, writeset); 1134 break; 1135 default: 1136 ret = -1; 1137 break; 1138 } 1139 if (ret < 0) { 1140 chan_mark_dead(c); 1141 } else if (ret == 0) { 1142 debug2("channel %d: pre_dynamic: need more", c->self); 1143 /* need more */ 1144 FD_SET(c->sock, readset); 1145 } else { 1146 /* switch to the next state */ 1147 c->type = SSH_CHANNEL_OPENING; 1148 port_open_helper(c, "direct-tcpip"); 1149 } 1150 } 1151 1152 /* This is our fake X11 server socket. */ 1153 static void 1154 channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) 1155 { 1156 Channel *nc; 1157 struct sockaddr addr; 1158 int newsock; 1159 socklen_t addrlen; 1160 char buf[16384], *remote_ipaddr; 1161 int remote_port; 1162 1163 if (FD_ISSET(c->sock, readset)) { 1164 debug("X11 connection requested."); 1165 addrlen = sizeof(addr); 1166 newsock = accept(c->sock, &addr, &addrlen); 1167 if (c->single_connection) { 1168 debug2("single_connection: closing X11 listener."); 1169 channel_close_fd(&c->sock); 1170 chan_mark_dead(c); 1171 } 1172 if (newsock < 0) { 1173 error("accept: %.100s", strerror(errno)); 1174 return; 1175 } 1176 set_nodelay(newsock); 1177 remote_ipaddr = get_peer_ipaddr(newsock); 1178 remote_port = get_peer_port(newsock); 1179 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1180 remote_ipaddr, remote_port); 1181 1182 nc = channel_new("accepted x11 socket", 1183 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1184 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1185 if (compat20) { 1186 packet_start(SSH2_MSG_CHANNEL_OPEN); 1187 packet_put_cstring("x11"); 1188 packet_put_int(nc->self); 1189 packet_put_int(nc->local_window_max); 1190 packet_put_int(nc->local_maxpacket); 1191 /* originator ipaddr and port */ 1192 packet_put_cstring(remote_ipaddr); 1193 if (datafellows & SSH_BUG_X11FWD) { 1194 debug2("ssh2 x11 bug compat mode"); 1195 } else { 1196 packet_put_int(remote_port); 1197 } 1198 packet_send(); 1199 } else { 1200 packet_start(SSH_SMSG_X11_OPEN); 1201 packet_put_int(nc->self); 1202 if (packet_get_protocol_flags() & 1203 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1204 packet_put_cstring(buf); 1205 packet_send(); 1206 } 1207 xfree(remote_ipaddr); 1208 } 1209 } 1210 1211 static void 1212 port_open_helper(Channel *c, char *rtype) 1213 { 1214 int direct; 1215 char buf[1024]; 1216 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1217 int remote_port = get_peer_port(c->sock); 1218 1219 direct = (strcmp(rtype, "direct-tcpip") == 0); 1220 1221 snprintf(buf, sizeof buf, 1222 "%s: listening port %d for %.100s port %d, " 1223 "connect from %.200s port %d", 1224 rtype, c->listening_port, c->path, c->host_port, 1225 remote_ipaddr, remote_port); 1226 1227 xfree(c->remote_name); 1228 c->remote_name = xstrdup(buf); 1229 1230 if (compat20) { 1231 packet_start(SSH2_MSG_CHANNEL_OPEN); 1232 packet_put_cstring(rtype); 1233 packet_put_int(c->self); 1234 packet_put_int(c->local_window_max); 1235 packet_put_int(c->local_maxpacket); 1236 if (direct) { 1237 /* target host, port */ 1238 packet_put_cstring(c->path); 1239 packet_put_int(c->host_port); 1240 } else { 1241 /* listen address, port */ 1242 packet_put_cstring(c->path); 1243 packet_put_int(c->listening_port); 1244 } 1245 /* originator host and port */ 1246 packet_put_cstring(remote_ipaddr); 1247 packet_put_int((u_int)remote_port); 1248 packet_send(); 1249 } else { 1250 packet_start(SSH_MSG_PORT_OPEN); 1251 packet_put_int(c->self); 1252 packet_put_cstring(c->path); 1253 packet_put_int(c->host_port); 1254 if (packet_get_protocol_flags() & 1255 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1256 packet_put_cstring(c->remote_name); 1257 packet_send(); 1258 } 1259 xfree(remote_ipaddr); 1260 } 1261 1262 static void 1263 channel_set_reuseaddr(int fd) 1264 { 1265 int on = 1; 1266 1267 /* 1268 * Set socket options. 1269 * Allow local port reuse in TIME_WAIT. 1270 */ 1271 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) 1272 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); 1273 } 1274 1275 /* 1276 * This socket is listening for connections to a forwarded TCP/IP port. 1277 */ 1278 static void 1279 channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset) 1280 { 1281 Channel *nc; 1282 struct sockaddr addr; 1283 int newsock, nextstate; 1284 socklen_t addrlen; 1285 char *rtype; 1286 1287 if (FD_ISSET(c->sock, readset)) { 1288 debug("Connection to port %d forwarding " 1289 "to %.100s port %d requested.", 1290 c->listening_port, c->path, c->host_port); 1291 1292 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1293 nextstate = SSH_CHANNEL_OPENING; 1294 rtype = "forwarded-tcpip"; 1295 } else { 1296 if (c->host_port == 0) { 1297 nextstate = SSH_CHANNEL_DYNAMIC; 1298 rtype = "dynamic-tcpip"; 1299 } else { 1300 nextstate = SSH_CHANNEL_OPENING; 1301 rtype = "direct-tcpip"; 1302 } 1303 } 1304 1305 addrlen = sizeof(addr); 1306 newsock = accept(c->sock, &addr, &addrlen); 1307 if (newsock < 0) { 1308 error("accept: %.100s", strerror(errno)); 1309 return; 1310 } 1311 set_nodelay(newsock); 1312 nc = channel_new(rtype, nextstate, newsock, newsock, -1, 1313 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1314 nc->listening_port = c->listening_port; 1315 nc->host_port = c->host_port; 1316 strlcpy(nc->path, c->path, sizeof(nc->path)); 1317 1318 if (nextstate == SSH_CHANNEL_DYNAMIC) { 1319 /* 1320 * do not call the channel_post handler until 1321 * this flag has been reset by a pre-handler. 1322 * otherwise the FD_ISSET calls might overflow 1323 */ 1324 nc->delayed = 1; 1325 } else { 1326 port_open_helper(nc, rtype); 1327 } 1328 } 1329 } 1330 1331 /* 1332 * This is the authentication agent socket listening for connections from 1333 * clients. 1334 */ 1335 static void 1336 channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset) 1337 { 1338 Channel *nc; 1339 int newsock; 1340 struct sockaddr addr; 1341 socklen_t addrlen; 1342 1343 if (FD_ISSET(c->sock, readset)) { 1344 addrlen = sizeof(addr); 1345 newsock = accept(c->sock, &addr, &addrlen); 1346 if (newsock < 0) { 1347 error("accept from auth socket: %.100s", strerror(errno)); 1348 return; 1349 } 1350 nc = channel_new("accepted auth socket", 1351 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1352 c->local_window_max, c->local_maxpacket, 1353 0, "accepted auth socket", 1); 1354 if (compat20) { 1355 packet_start(SSH2_MSG_CHANNEL_OPEN); 1356 packet_put_cstring("auth-agent@openssh.com"); 1357 packet_put_int(nc->self); 1358 packet_put_int(c->local_window_max); 1359 packet_put_int(c->local_maxpacket); 1360 } else { 1361 packet_start(SSH_SMSG_AGENT_OPEN); 1362 packet_put_int(nc->self); 1363 } 1364 packet_send(); 1365 } 1366 } 1367 1368 static void 1369 channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset) 1370 { 1371 int err = 0; 1372 socklen_t sz = sizeof(err); 1373 1374 if (FD_ISSET(c->sock, writeset)) { 1375 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { 1376 err = errno; 1377 error("getsockopt SO_ERROR failed"); 1378 } 1379 if (err == 0) { 1380 debug("channel %d: connected", c->self); 1381 c->type = SSH_CHANNEL_OPEN; 1382 if (compat20) { 1383 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1384 packet_put_int(c->remote_id); 1385 packet_put_int(c->self); 1386 packet_put_int(c->local_window); 1387 packet_put_int(c->local_maxpacket); 1388 } else { 1389 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1390 packet_put_int(c->remote_id); 1391 packet_put_int(c->self); 1392 } 1393 } else { 1394 debug("channel %d: not connected: %s", 1395 c->self, strerror(err)); 1396 if (compat20) { 1397 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1398 packet_put_int(c->remote_id); 1399 packet_put_int(SSH2_OPEN_CONNECT_FAILED); 1400 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1401 packet_put_cstring(strerror(err)); 1402 packet_put_cstring(""); 1403 } 1404 } else { 1405 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1406 packet_put_int(c->remote_id); 1407 } 1408 chan_mark_dead(c); 1409 } 1410 packet_send(); 1411 } 1412 } 1413 1414 static int 1415 channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset) 1416 { 1417 char buf[CHAN_RBUF]; 1418 int len; 1419 1420 if (c->rfd != -1 && 1421 FD_ISSET(c->rfd, readset)) { 1422 len = read(c->rfd, buf, sizeof(buf)); 1423 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1424 return 1; 1425 if (len <= 0) { 1426 debug2("channel %d: read<=0 rfd %d len %d", 1427 c->self, c->rfd, len); 1428 if (c->type != SSH_CHANNEL_OPEN) { 1429 debug2("channel %d: not open", c->self); 1430 chan_mark_dead(c); 1431 return -1; 1432 } else if (compat13) { 1433 buffer_clear(&c->output); 1434 c->type = SSH_CHANNEL_INPUT_DRAINING; 1435 debug2("channel %d: input draining.", c->self); 1436 } else { 1437 chan_read_failed(c); 1438 } 1439 return -1; 1440 } 1441 if (c->input_filter != NULL) { 1442 if (c->input_filter(c, buf, len) == -1) { 1443 debug2("channel %d: filter stops", c->self); 1444 chan_read_failed(c); 1445 } 1446 } else if (c->datagram) { 1447 buffer_put_string(&c->input, buf, len); 1448 } else { 1449 buffer_append(&c->input, buf, len); 1450 } 1451 } 1452 return 1; 1453 } 1454 static int 1455 channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) 1456 { 1457 struct termios tio; 1458 u_char *data = NULL, *buf; 1459 u_int dlen; 1460 int len; 1461 1462 /* Send buffered output data to the socket. */ 1463 if (c->wfd != -1 && 1464 FD_ISSET(c->wfd, writeset) && 1465 buffer_len(&c->output) > 0) { 1466 if (c->output_filter != NULL) { 1467 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) { 1468 debug2("channel %d: filter stops", c->self); 1469 if (c->type != SSH_CHANNEL_OPEN) 1470 chan_mark_dead(c); 1471 else 1472 chan_write_failed(c); 1473 return -1; 1474 } 1475 } else if (c->datagram) { 1476 buf = data = buffer_get_string(&c->output, &dlen); 1477 } else { 1478 buf = data = buffer_ptr(&c->output); 1479 dlen = buffer_len(&c->output); 1480 } 1481 1482 if (c->datagram) { 1483 /* ignore truncated writes, datagrams might get lost */ 1484 c->local_consumed += dlen + 4; 1485 len = write(c->wfd, buf, dlen); 1486 xfree(data); 1487 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1488 return 1; 1489 if (len <= 0) { 1490 if (c->type != SSH_CHANNEL_OPEN) 1491 chan_mark_dead(c); 1492 else 1493 chan_write_failed(c); 1494 return -1; 1495 } 1496 return 1; 1497 } 1498 #ifdef _AIX 1499 /* XXX: Later AIX versions can't push as much data to tty */ 1500 if (compat20 && c->wfd_isatty) 1501 dlen = MIN(dlen, 8*1024); 1502 #endif 1503 1504 len = write(c->wfd, buf, dlen); 1505 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1506 return 1; 1507 if (len <= 0) { 1508 if (c->type != SSH_CHANNEL_OPEN) { 1509 debug2("channel %d: not open", c->self); 1510 chan_mark_dead(c); 1511 return -1; 1512 } else if (compat13) { 1513 buffer_clear(&c->output); 1514 debug2("channel %d: input draining.", c->self); 1515 c->type = SSH_CHANNEL_INPUT_DRAINING; 1516 } else { 1517 chan_write_failed(c); 1518 } 1519 return -1; 1520 } 1521 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') { 1522 if (tcgetattr(c->wfd, &tio) == 0 && 1523 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 1524 /* 1525 * Simulate echo to reduce the impact of 1526 * traffic analysis. We need to match the 1527 * size of a SSH2_MSG_CHANNEL_DATA message 1528 * (4 byte channel id + buf) 1529 */ 1530 packet_send_ignore(4 + len); 1531 packet_send(); 1532 } 1533 } 1534 buffer_consume(&c->output, len); 1535 if (compat20 && len > 0) { 1536 c->local_consumed += len; 1537 } 1538 } 1539 return 1; 1540 } 1541 static int 1542 channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset) 1543 { 1544 char buf[CHAN_RBUF]; 1545 int len; 1546 1547 /** XXX handle drain efd, too */ 1548 if (c->efd != -1) { 1549 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1550 FD_ISSET(c->efd, writeset) && 1551 buffer_len(&c->extended) > 0) { 1552 len = write(c->efd, buffer_ptr(&c->extended), 1553 buffer_len(&c->extended)); 1554 debug2("channel %d: written %d to efd %d", 1555 c->self, len, c->efd); 1556 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1557 return 1; 1558 if (len <= 0) { 1559 debug2("channel %d: closing write-efd %d", 1560 c->self, c->efd); 1561 channel_close_fd(&c->efd); 1562 } else { 1563 buffer_consume(&c->extended, len); 1564 c->local_consumed += len; 1565 } 1566 } else if (c->extended_usage == CHAN_EXTENDED_READ && 1567 FD_ISSET(c->efd, readset)) { 1568 len = read(c->efd, buf, sizeof(buf)); 1569 debug2("channel %d: read %d from efd %d", 1570 c->self, len, c->efd); 1571 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1572 return 1; 1573 if (len <= 0) { 1574 debug2("channel %d: closing read-efd %d", 1575 c->self, c->efd); 1576 channel_close_fd(&c->efd); 1577 } else { 1578 buffer_append(&c->extended, buf, len); 1579 } 1580 } 1581 } 1582 return 1; 1583 } 1584 static int 1585 channel_handle_ctl(Channel *c, fd_set * readset, fd_set * writeset) 1586 { 1587 char buf[16]; 1588 int len; 1589 1590 /* Monitor control fd to detect if the slave client exits */ 1591 if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) { 1592 len = read(c->ctl_fd, buf, sizeof(buf)); 1593 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1594 return 1; 1595 if (len <= 0) { 1596 debug2("channel %d: ctl read<=0", c->self); 1597 if (c->type != SSH_CHANNEL_OPEN) { 1598 debug2("channel %d: not open", c->self); 1599 chan_mark_dead(c); 1600 return -1; 1601 } else { 1602 chan_read_failed(c); 1603 chan_write_failed(c); 1604 } 1605 return -1; 1606 } else 1607 fatal("%s: unexpected data on ctl fd", __func__); 1608 } 1609 return 1; 1610 } 1611 static int 1612 channel_check_window(Channel *c) 1613 { 1614 if (c->type == SSH_CHANNEL_OPEN && 1615 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 1616 c->local_window < c->local_window_max/2 && 1617 c->local_consumed > 0) { 1618 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 1619 packet_put_int(c->remote_id); 1620 packet_put_int(c->local_consumed); 1621 packet_send(); 1622 debug2("channel %d: window %d sent adjust %d", 1623 c->self, c->local_window, 1624 c->local_consumed); 1625 c->local_window += c->local_consumed; 1626 c->local_consumed = 0; 1627 } 1628 return 1; 1629 } 1630 1631 static void 1632 channel_post_open(Channel *c, fd_set * readset, fd_set * writeset) 1633 { 1634 if (c->delayed) 1635 return; 1636 channel_handle_rfd(c, readset, writeset); 1637 channel_handle_wfd(c, readset, writeset); 1638 if (!compat20) 1639 return; 1640 channel_handle_efd(c, readset, writeset); 1641 channel_handle_ctl(c, readset, writeset); 1642 channel_check_window(c); 1643 } 1644 1645 static void 1646 channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset) 1647 { 1648 int len; 1649 1650 /* Send buffered output data to the socket. */ 1651 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { 1652 len = write(c->sock, buffer_ptr(&c->output), 1653 buffer_len(&c->output)); 1654 if (len <= 0) 1655 buffer_clear(&c->output); 1656 else 1657 buffer_consume(&c->output, len); 1658 } 1659 } 1660 1661 static void 1662 channel_handler_init_20(void) 1663 { 1664 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 1665 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 1666 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 1667 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 1668 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 1669 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 1670 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 1671 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 1672 1673 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 1674 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 1675 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 1676 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 1677 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 1678 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 1679 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 1680 } 1681 1682 static void 1683 channel_handler_init_13(void) 1684 { 1685 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; 1686 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; 1687 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 1688 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 1689 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 1690 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; 1691 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; 1692 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 1693 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 1694 1695 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 1696 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 1697 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 1698 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 1699 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; 1700 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 1701 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 1702 } 1703 1704 static void 1705 channel_handler_init_15(void) 1706 { 1707 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 1708 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 1709 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 1710 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 1711 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 1712 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 1713 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 1714 1715 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 1716 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 1717 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 1718 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 1719 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 1720 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 1721 } 1722 1723 static void 1724 channel_handler_init(void) 1725 { 1726 int i; 1727 1728 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { 1729 channel_pre[i] = NULL; 1730 channel_post[i] = NULL; 1731 } 1732 if (compat20) 1733 channel_handler_init_20(); 1734 else if (compat13) 1735 channel_handler_init_13(); 1736 else 1737 channel_handler_init_15(); 1738 } 1739 1740 /* gc dead channels */ 1741 static void 1742 channel_garbage_collect(Channel *c) 1743 { 1744 if (c == NULL) 1745 return; 1746 if (c->detach_user != NULL) { 1747 if (!chan_is_dead(c, c->detach_close)) 1748 return; 1749 debug2("channel %d: gc: notify user", c->self); 1750 c->detach_user(c->self, NULL); 1751 /* if we still have a callback */ 1752 if (c->detach_user != NULL) 1753 return; 1754 debug2("channel %d: gc: user detached", c->self); 1755 } 1756 if (!chan_is_dead(c, 1)) 1757 return; 1758 debug2("channel %d: garbage collecting", c->self); 1759 channel_free(c); 1760 } 1761 1762 static void 1763 channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset) 1764 { 1765 static int did_init = 0; 1766 u_int i; 1767 Channel *c; 1768 1769 if (!did_init) { 1770 channel_handler_init(); 1771 did_init = 1; 1772 } 1773 for (i = 0; i < channels_alloc; i++) { 1774 c = channels[i]; 1775 if (c == NULL) 1776 continue; 1777 if (ftab[c->type] != NULL) 1778 (*ftab[c->type])(c, readset, writeset); 1779 channel_garbage_collect(c); 1780 } 1781 } 1782 1783 /* 1784 * Allocate/update select bitmasks and add any bits relevant to channels in 1785 * select bitmasks. 1786 */ 1787 void 1788 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, 1789 u_int *nallocp, int rekeying) 1790 { 1791 u_int n, sz; 1792 1793 n = MAX(*maxfdp, channel_max_fd); 1794 1795 sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); 1796 /* perhaps check sz < nalloc/2 and shrink? */ 1797 if (*readsetp == NULL || sz > *nallocp) { 1798 *readsetp = xrealloc(*readsetp, sz); 1799 *writesetp = xrealloc(*writesetp, sz); 1800 *nallocp = sz; 1801 } 1802 *maxfdp = n; 1803 memset(*readsetp, 0, sz); 1804 memset(*writesetp, 0, sz); 1805 1806 if (!rekeying) 1807 channel_handler(channel_pre, *readsetp, *writesetp); 1808 } 1809 1810 /* 1811 * After select, perform any appropriate operations for channels which have 1812 * events pending. 1813 */ 1814 void 1815 channel_after_select(fd_set * readset, fd_set * writeset) 1816 { 1817 channel_handler(channel_post, readset, writeset); 1818 } 1819 1820 1821 /* If there is data to send to the connection, enqueue some of it now. */ 1822 1823 void 1824 channel_output_poll(void) 1825 { 1826 Channel *c; 1827 u_int i, len; 1828 1829 for (i = 0; i < channels_alloc; i++) { 1830 c = channels[i]; 1831 if (c == NULL) 1832 continue; 1833 1834 /* 1835 * We are only interested in channels that can have buffered 1836 * incoming data. 1837 */ 1838 if (compat13) { 1839 if (c->type != SSH_CHANNEL_OPEN && 1840 c->type != SSH_CHANNEL_INPUT_DRAINING) 1841 continue; 1842 } else { 1843 if (c->type != SSH_CHANNEL_OPEN) 1844 continue; 1845 } 1846 if (compat20 && 1847 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 1848 /* XXX is this true? */ 1849 debug3("channel %d: will not send data after close", c->self); 1850 continue; 1851 } 1852 1853 /* Get the amount of buffered data for this channel. */ 1854 if ((c->istate == CHAN_INPUT_OPEN || 1855 c->istate == CHAN_INPUT_WAIT_DRAIN) && 1856 (len = buffer_len(&c->input)) > 0) { 1857 if (c->datagram) { 1858 if (len > 0) { 1859 u_char *data; 1860 u_int dlen; 1861 1862 data = buffer_get_string(&c->input, 1863 &dlen); 1864 packet_start(SSH2_MSG_CHANNEL_DATA); 1865 packet_put_int(c->remote_id); 1866 packet_put_string(data, dlen); 1867 packet_send(); 1868 c->remote_window -= dlen + 4; 1869 xfree(data); 1870 } 1871 continue; 1872 } 1873 /* 1874 * Send some data for the other side over the secure 1875 * connection. 1876 */ 1877 if (compat20) { 1878 if (len > c->remote_window) 1879 len = c->remote_window; 1880 if (len > c->remote_maxpacket) 1881 len = c->remote_maxpacket; 1882 } else { 1883 if (packet_is_interactive()) { 1884 if (len > 1024) 1885 len = 512; 1886 } else { 1887 /* Keep the packets at reasonable size. */ 1888 if (len > packet_get_maxsize()/2) 1889 len = packet_get_maxsize()/2; 1890 } 1891 } 1892 if (len > 0) { 1893 packet_start(compat20 ? 1894 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); 1895 packet_put_int(c->remote_id); 1896 packet_put_string(buffer_ptr(&c->input), len); 1897 packet_send(); 1898 buffer_consume(&c->input, len); 1899 c->remote_window -= len; 1900 } 1901 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1902 if (compat13) 1903 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); 1904 /* 1905 * input-buffer is empty and read-socket shutdown: 1906 * tell peer, that we will not send more data: send IEOF. 1907 * hack for extended data: delay EOF if EFD still in use. 1908 */ 1909 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 1910 debug2("channel %d: ibuf_empty delayed efd %d/(%d)", 1911 c->self, c->efd, buffer_len(&c->extended)); 1912 else 1913 chan_ibuf_empty(c); 1914 } 1915 /* Send extended data, i.e. stderr */ 1916 if (compat20 && 1917 !(c->flags & CHAN_EOF_SENT) && 1918 c->remote_window > 0 && 1919 (len = buffer_len(&c->extended)) > 0 && 1920 c->extended_usage == CHAN_EXTENDED_READ) { 1921 debug2("channel %d: rwin %u elen %u euse %d", 1922 c->self, c->remote_window, buffer_len(&c->extended), 1923 c->extended_usage); 1924 if (len > c->remote_window) 1925 len = c->remote_window; 1926 if (len > c->remote_maxpacket) 1927 len = c->remote_maxpacket; 1928 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); 1929 packet_put_int(c->remote_id); 1930 packet_put_int(SSH2_EXTENDED_DATA_STDERR); 1931 packet_put_string(buffer_ptr(&c->extended), len); 1932 packet_send(); 1933 buffer_consume(&c->extended, len); 1934 c->remote_window -= len; 1935 debug2("channel %d: sent ext data %d", c->self, len); 1936 } 1937 } 1938 } 1939 1940 1941 /* -- protocol input */ 1942 1943 void 1944 channel_input_data(int type, u_int32_t seq, void *ctxt) 1945 { 1946 int id; 1947 char *data; 1948 u_int data_len; 1949 Channel *c; 1950 1951 /* Get the channel number and verify it. */ 1952 id = packet_get_int(); 1953 c = channel_lookup(id); 1954 if (c == NULL) 1955 packet_disconnect("Received data for nonexistent channel %d.", id); 1956 1957 /* Ignore any data for non-open channels (might happen on close) */ 1958 if (c->type != SSH_CHANNEL_OPEN && 1959 c->type != SSH_CHANNEL_X11_OPEN) 1960 return; 1961 1962 /* Get the data. */ 1963 data = packet_get_string(&data_len); 1964 1965 /* 1966 * Ignore data for protocol > 1.3 if output end is no longer open. 1967 * For protocol 2 the sending side is reducing its window as it sends 1968 * data, so we must 'fake' consumption of the data in order to ensure 1969 * that window updates are sent back. Otherwise the connection might 1970 * deadlock. 1971 */ 1972 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { 1973 if (compat20) { 1974 c->local_window -= data_len; 1975 c->local_consumed += data_len; 1976 } 1977 xfree(data); 1978 return; 1979 } 1980 1981 if (compat20) { 1982 if (data_len > c->local_maxpacket) { 1983 logit("channel %d: rcvd big packet %d, maxpack %d", 1984 c->self, data_len, c->local_maxpacket); 1985 } 1986 if (data_len > c->local_window) { 1987 logit("channel %d: rcvd too much data %d, win %d", 1988 c->self, data_len, c->local_window); 1989 xfree(data); 1990 return; 1991 } 1992 c->local_window -= data_len; 1993 } 1994 packet_check_eom(); 1995 if (c->datagram) 1996 buffer_put_string(&c->output, data, data_len); 1997 else 1998 buffer_append(&c->output, data, data_len); 1999 xfree(data); 2000 } 2001 2002 void 2003 channel_input_extended_data(int type, u_int32_t seq, void *ctxt) 2004 { 2005 int id; 2006 char *data; 2007 u_int data_len, tcode; 2008 Channel *c; 2009 2010 /* Get the channel number and verify it. */ 2011 id = packet_get_int(); 2012 c = channel_lookup(id); 2013 2014 if (c == NULL) 2015 packet_disconnect("Received extended_data for bad channel %d.", id); 2016 if (c->type != SSH_CHANNEL_OPEN) { 2017 logit("channel %d: ext data for non open", id); 2018 return; 2019 } 2020 if (c->flags & CHAN_EOF_RCVD) { 2021 if (datafellows & SSH_BUG_EXTEOF) 2022 debug("channel %d: accepting ext data after eof", id); 2023 else 2024 packet_disconnect("Received extended_data after EOF " 2025 "on channel %d.", id); 2026 } 2027 tcode = packet_get_int(); 2028 if (c->efd == -1 || 2029 c->extended_usage != CHAN_EXTENDED_WRITE || 2030 tcode != SSH2_EXTENDED_DATA_STDERR) { 2031 logit("channel %d: bad ext data", c->self); 2032 return; 2033 } 2034 data = packet_get_string(&data_len); 2035 packet_check_eom(); 2036 if (data_len > c->local_window) { 2037 logit("channel %d: rcvd too much extended_data %d, win %d", 2038 c->self, data_len, c->local_window); 2039 xfree(data); 2040 return; 2041 } 2042 debug2("channel %d: rcvd ext data %d", c->self, data_len); 2043 c->local_window -= data_len; 2044 buffer_append(&c->extended, data, data_len); 2045 xfree(data); 2046 } 2047 2048 void 2049 channel_input_ieof(int type, u_int32_t seq, void *ctxt) 2050 { 2051 int id; 2052 Channel *c; 2053 2054 id = packet_get_int(); 2055 packet_check_eom(); 2056 c = channel_lookup(id); 2057 if (c == NULL) 2058 packet_disconnect("Received ieof for nonexistent channel %d.", id); 2059 chan_rcvd_ieof(c); 2060 2061 /* XXX force input close */ 2062 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 2063 debug("channel %d: FORCE input drain", c->self); 2064 c->istate = CHAN_INPUT_WAIT_DRAIN; 2065 if (buffer_len(&c->input) == 0) 2066 chan_ibuf_empty(c); 2067 } 2068 2069 } 2070 2071 void 2072 channel_input_close(int type, u_int32_t seq, void *ctxt) 2073 { 2074 int id; 2075 Channel *c; 2076 2077 id = packet_get_int(); 2078 packet_check_eom(); 2079 c = channel_lookup(id); 2080 if (c == NULL) 2081 packet_disconnect("Received close for nonexistent channel %d.", id); 2082 2083 /* 2084 * Send a confirmation that we have closed the channel and no more 2085 * data is coming for it. 2086 */ 2087 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); 2088 packet_put_int(c->remote_id); 2089 packet_send(); 2090 2091 /* 2092 * If the channel is in closed state, we have sent a close request, 2093 * and the other side will eventually respond with a confirmation. 2094 * Thus, we cannot free the channel here, because then there would be 2095 * no-one to receive the confirmation. The channel gets freed when 2096 * the confirmation arrives. 2097 */ 2098 if (c->type != SSH_CHANNEL_CLOSED) { 2099 /* 2100 * Not a closed channel - mark it as draining, which will 2101 * cause it to be freed later. 2102 */ 2103 buffer_clear(&c->input); 2104 c->type = SSH_CHANNEL_OUTPUT_DRAINING; 2105 } 2106 } 2107 2108 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ 2109 void 2110 channel_input_oclose(int type, u_int32_t seq, void *ctxt) 2111 { 2112 int id = packet_get_int(); 2113 Channel *c = channel_lookup(id); 2114 2115 packet_check_eom(); 2116 if (c == NULL) 2117 packet_disconnect("Received oclose for nonexistent channel %d.", id); 2118 chan_rcvd_oclose(c); 2119 } 2120 2121 void 2122 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) 2123 { 2124 int id = packet_get_int(); 2125 Channel *c = channel_lookup(id); 2126 2127 packet_check_eom(); 2128 if (c == NULL) 2129 packet_disconnect("Received close confirmation for " 2130 "out-of-range channel %d.", id); 2131 if (c->type != SSH_CHANNEL_CLOSED) 2132 packet_disconnect("Received close confirmation for " 2133 "non-closed channel %d (type %d).", id, c->type); 2134 channel_free(c); 2135 } 2136 2137 void 2138 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) 2139 { 2140 int id, remote_id; 2141 Channel *c; 2142 2143 id = packet_get_int(); 2144 c = channel_lookup(id); 2145 2146 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2147 packet_disconnect("Received open confirmation for " 2148 "non-opening channel %d.", id); 2149 remote_id = packet_get_int(); 2150 /* Record the remote channel number and mark that the channel is now open. */ 2151 c->remote_id = remote_id; 2152 c->type = SSH_CHANNEL_OPEN; 2153 2154 if (compat20) { 2155 c->remote_window = packet_get_int(); 2156 c->remote_maxpacket = packet_get_int(); 2157 if (c->confirm) { 2158 debug2("callback start"); 2159 c->confirm(c->self, c->confirm_ctx); 2160 debug2("callback done"); 2161 } 2162 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 2163 c->remote_window, c->remote_maxpacket); 2164 } 2165 packet_check_eom(); 2166 } 2167 2168 static char * 2169 reason2txt(int reason) 2170 { 2171 switch (reason) { 2172 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 2173 return "administratively prohibited"; 2174 case SSH2_OPEN_CONNECT_FAILED: 2175 return "connect failed"; 2176 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 2177 return "unknown channel type"; 2178 case SSH2_OPEN_RESOURCE_SHORTAGE: 2179 return "resource shortage"; 2180 } 2181 return "unknown reason"; 2182 } 2183 2184 void 2185 channel_input_open_failure(int type, u_int32_t seq, void *ctxt) 2186 { 2187 int id, reason; 2188 char *msg = NULL, *lang = NULL; 2189 Channel *c; 2190 2191 id = packet_get_int(); 2192 c = channel_lookup(id); 2193 2194 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2195 packet_disconnect("Received open failure for " 2196 "non-opening channel %d.", id); 2197 if (compat20) { 2198 reason = packet_get_int(); 2199 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 2200 msg = packet_get_string(NULL); 2201 lang = packet_get_string(NULL); 2202 } 2203 logit("channel %d: open failed: %s%s%s", id, 2204 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 2205 if (msg != NULL) 2206 xfree(msg); 2207 if (lang != NULL) 2208 xfree(lang); 2209 } 2210 packet_check_eom(); 2211 /* Free the channel. This will also close the socket. */ 2212 channel_free(c); 2213 } 2214 2215 void 2216 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) 2217 { 2218 Channel *c; 2219 int id; 2220 u_int adjust; 2221 2222 if (!compat20) 2223 return; 2224 2225 /* Get the channel number and verify it. */ 2226 id = packet_get_int(); 2227 c = channel_lookup(id); 2228 2229 if (c == NULL) { 2230 logit("Received window adjust for non-open channel %d.", id); 2231 return; 2232 } 2233 adjust = packet_get_int(); 2234 packet_check_eom(); 2235 debug2("channel %d: rcvd adjust %u", id, adjust); 2236 c->remote_window += adjust; 2237 } 2238 2239 void 2240 channel_input_port_open(int type, u_int32_t seq, void *ctxt) 2241 { 2242 Channel *c = NULL; 2243 u_short host_port; 2244 char *host, *originator_string; 2245 int remote_id, sock = -1; 2246 2247 remote_id = packet_get_int(); 2248 host = packet_get_string(NULL); 2249 host_port = packet_get_int(); 2250 2251 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 2252 originator_string = packet_get_string(NULL); 2253 } else { 2254 originator_string = xstrdup("unknown (remote did not supply name)"); 2255 } 2256 packet_check_eom(); 2257 sock = channel_connect_to(host, host_port); 2258 if (sock != -1) { 2259 c = channel_new("connected socket", 2260 SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0, 2261 originator_string, 1); 2262 c->remote_id = remote_id; 2263 } 2264 xfree(originator_string); 2265 if (c == NULL) { 2266 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 2267 packet_put_int(remote_id); 2268 packet_send(); 2269 } 2270 xfree(host); 2271 } 2272 2273 2274 /* -- tcp forwarding */ 2275 2276 void 2277 channel_set_af(int af) 2278 { 2279 IPv4or6 = af; 2280 } 2281 2282 static int 2283 channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port, 2284 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2285 { 2286 Channel *c; 2287 int sock, r, success = 0, wildcard = 0, is_client; 2288 struct addrinfo hints, *ai, *aitop; 2289 const char *host, *addr; 2290 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 2291 2292 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 2293 listen_addr : host_to_connect; 2294 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 2295 2296 if (host == NULL) { 2297 error("No forward host name."); 2298 return 0; 2299 } 2300 if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) { 2301 error("Forward host name too long."); 2302 return 0; 2303 } 2304 2305 /* 2306 * Determine whether or not a port forward listens to loopback, 2307 * specified address or wildcard. On the client, a specified bind 2308 * address will always override gateway_ports. On the server, a 2309 * gateway_ports of 1 (``yes'') will override the client's 2310 * specification and force a wildcard bind, whereas a value of 2 2311 * (``clientspecified'') will bind to whatever address the client 2312 * asked for. 2313 * 2314 * Special-case listen_addrs are: 2315 * 2316 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 2317 * "" (empty string), "*" -> wildcard v4/v6 2318 * "localhost" -> loopback v4/v6 2319 */ 2320 addr = NULL; 2321 if (listen_addr == NULL) { 2322 /* No address specified: default to gateway_ports setting */ 2323 if (gateway_ports) 2324 wildcard = 1; 2325 } else if (gateway_ports || is_client) { 2326 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 2327 strcmp(listen_addr, "0.0.0.0") == 0) || 2328 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 2329 (!is_client && gateway_ports == 1)) 2330 wildcard = 1; 2331 else if (strcmp(listen_addr, "localhost") != 0) 2332 addr = listen_addr; 2333 } 2334 2335 debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s", 2336 type, wildcard, (addr == NULL) ? "NULL" : addr); 2337 2338 /* 2339 * getaddrinfo returns a loopback address if the hostname is 2340 * set to NULL and hints.ai_flags is not AI_PASSIVE 2341 */ 2342 memset(&hints, 0, sizeof(hints)); 2343 hints.ai_family = IPv4or6; 2344 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 2345 hints.ai_socktype = SOCK_STREAM; 2346 snprintf(strport, sizeof strport, "%d", listen_port); 2347 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 2348 if (addr == NULL) { 2349 /* This really shouldn't happen */ 2350 packet_disconnect("getaddrinfo: fatal error: %s", 2351 gai_strerror(r)); 2352 } else { 2353 error("channel_setup_fwd_listener: " 2354 "getaddrinfo(%.64s): %s", addr, gai_strerror(r)); 2355 } 2356 return 0; 2357 } 2358 2359 for (ai = aitop; ai; ai = ai->ai_next) { 2360 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 2361 continue; 2362 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 2363 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 2364 error("channel_setup_fwd_listener: getnameinfo failed"); 2365 continue; 2366 } 2367 /* Create a port to listen for the host. */ 2368 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 2369 if (sock < 0) { 2370 /* this is no error since kernel may not support ipv6 */ 2371 verbose("socket: %.100s", strerror(errno)); 2372 continue; 2373 } 2374 2375 channel_set_reuseaddr(sock); 2376 2377 debug("Local forwarding listening on %s port %s.", ntop, strport); 2378 2379 /* Bind the socket to the address. */ 2380 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 2381 /* address can be in use ipv6 address is already bound */ 2382 if (!ai->ai_next) 2383 error("bind: %.100s", strerror(errno)); 2384 else 2385 verbose("bind: %.100s", strerror(errno)); 2386 2387 close(sock); 2388 continue; 2389 } 2390 /* Start listening for connections on the socket. */ 2391 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 2392 error("listen: %.100s", strerror(errno)); 2393 close(sock); 2394 continue; 2395 } 2396 /* Allocate a channel number for the socket. */ 2397 c = channel_new("port listener", type, sock, sock, -1, 2398 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 2399 0, "port listener", 1); 2400 strlcpy(c->path, host, sizeof(c->path)); 2401 c->host_port = port_to_connect; 2402 c->listening_port = listen_port; 2403 success = 1; 2404 } 2405 if (success == 0) 2406 error("channel_setup_fwd_listener: cannot listen to port: %d", 2407 listen_port); 2408 freeaddrinfo(aitop); 2409 return success; 2410 } 2411 2412 int 2413 channel_cancel_rport_listener(const char *host, u_short port) 2414 { 2415 u_int i; 2416 int found = 0; 2417 2418 for (i = 0; i < channels_alloc; i++) { 2419 Channel *c = channels[i]; 2420 2421 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER && 2422 strncmp(c->path, host, sizeof(c->path)) == 0 && 2423 c->listening_port == port) { 2424 debug2("%s: close channel %d", __func__, i); 2425 channel_free(c); 2426 found = 1; 2427 } 2428 } 2429 2430 return (found); 2431 } 2432 2433 /* protocol local port fwd, used by ssh (and sshd in v1) */ 2434 int 2435 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port, 2436 const char *host_to_connect, u_short port_to_connect, int gateway_ports) 2437 { 2438 return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, 2439 listen_host, listen_port, host_to_connect, port_to_connect, 2440 gateway_ports); 2441 } 2442 2443 /* protocol v2 remote port fwd, used by sshd */ 2444 int 2445 channel_setup_remote_fwd_listener(const char *listen_address, 2446 u_short listen_port, int gateway_ports) 2447 { 2448 return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, 2449 listen_address, listen_port, NULL, 0, gateway_ports); 2450 } 2451 2452 /* 2453 * Initiate forwarding of connections to port "port" on remote host through 2454 * the secure channel to host:port from local side. 2455 */ 2456 2457 void 2458 channel_request_remote_forwarding(const char *listen_host, u_short listen_port, 2459 const char *host_to_connect, u_short port_to_connect) 2460 { 2461 int type, success = 0; 2462 2463 /* Record locally that connection to this host/port is permitted. */ 2464 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) 2465 fatal("channel_request_remote_forwarding: too many forwards"); 2466 2467 /* Send the forward request to the remote side. */ 2468 if (compat20) { 2469 const char *address_to_bind; 2470 if (listen_host == NULL) 2471 address_to_bind = "localhost"; 2472 else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) 2473 address_to_bind = ""; 2474 else 2475 address_to_bind = listen_host; 2476 2477 packet_start(SSH2_MSG_GLOBAL_REQUEST); 2478 packet_put_cstring("tcpip-forward"); 2479 packet_put_char(1); /* boolean: want reply */ 2480 packet_put_cstring(address_to_bind); 2481 packet_put_int(listen_port); 2482 packet_send(); 2483 packet_write_wait(); 2484 /* Assume that server accepts the request */ 2485 success = 1; 2486 } else { 2487 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); 2488 packet_put_int(listen_port); 2489 packet_put_cstring(host_to_connect); 2490 packet_put_int(port_to_connect); 2491 packet_send(); 2492 packet_write_wait(); 2493 2494 /* Wait for response from the remote side. */ 2495 type = packet_read(); 2496 switch (type) { 2497 case SSH_SMSG_SUCCESS: 2498 success = 1; 2499 break; 2500 case SSH_SMSG_FAILURE: 2501 logit("Warning: Server denied remote port forwarding."); 2502 break; 2503 default: 2504 /* Unknown packet */ 2505 packet_disconnect("Protocol error for port forward request:" 2506 "received packet type %d.", type); 2507 } 2508 } 2509 if (success) { 2510 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); 2511 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; 2512 permitted_opens[num_permitted_opens].listen_port = listen_port; 2513 num_permitted_opens++; 2514 } 2515 } 2516 2517 /* 2518 * Request cancellation of remote forwarding of connection host:port from 2519 * local side. 2520 */ 2521 void 2522 channel_request_rforward_cancel(const char *host, u_short port) 2523 { 2524 int i; 2525 2526 if (!compat20) 2527 return; 2528 2529 for (i = 0; i < num_permitted_opens; i++) { 2530 if (permitted_opens[i].host_to_connect != NULL && 2531 permitted_opens[i].listen_port == port) 2532 break; 2533 } 2534 if (i >= num_permitted_opens) { 2535 debug("%s: requested forward not found", __func__); 2536 return; 2537 } 2538 packet_start(SSH2_MSG_GLOBAL_REQUEST); 2539 packet_put_cstring("cancel-tcpip-forward"); 2540 packet_put_char(0); 2541 packet_put_cstring(host == NULL ? "" : host); 2542 packet_put_int(port); 2543 packet_send(); 2544 2545 permitted_opens[i].listen_port = 0; 2546 permitted_opens[i].port_to_connect = 0; 2547 xfree(permitted_opens[i].host_to_connect); 2548 permitted_opens[i].host_to_connect = NULL; 2549 } 2550 2551 /* 2552 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates 2553 * listening for the port, and sends back a success reply (or disconnect 2554 * message if there was an error). This never returns if there was an error. 2555 */ 2556 2557 void 2558 channel_input_port_forward_request(int is_root, int gateway_ports) 2559 { 2560 u_short port, host_port; 2561 char *hostname; 2562 2563 /* Get arguments from the packet. */ 2564 port = packet_get_int(); 2565 hostname = packet_get_string(NULL); 2566 host_port = packet_get_int(); 2567 2568 #ifndef HAVE_CYGWIN 2569 /* 2570 * Check that an unprivileged user is not trying to forward a 2571 * privileged port. 2572 */ 2573 if (port < IPPORT_RESERVED && !is_root) 2574 packet_disconnect( 2575 "Requested forwarding of port %d but user is not root.", 2576 port); 2577 if (host_port == 0) 2578 packet_disconnect("Dynamic forwarding denied."); 2579 #endif 2580 2581 /* Initiate forwarding */ 2582 channel_setup_local_fwd_listener(NULL, port, hostname, 2583 host_port, gateway_ports); 2584 2585 /* Free the argument string. */ 2586 xfree(hostname); 2587 } 2588 2589 /* 2590 * Permits opening to any host/port if permitted_opens[] is empty. This is 2591 * usually called by the server, because the user could connect to any port 2592 * anyway, and the server has no way to know but to trust the client anyway. 2593 */ 2594 void 2595 channel_permit_all_opens(void) 2596 { 2597 if (num_permitted_opens == 0) 2598 all_opens_permitted = 1; 2599 } 2600 2601 void 2602 channel_add_permitted_opens(char *host, int port) 2603 { 2604 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) 2605 fatal("channel_request_remote_forwarding: too many forwards"); 2606 debug("allow port forwarding to host %s port %d", host, port); 2607 2608 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); 2609 permitted_opens[num_permitted_opens].port_to_connect = port; 2610 num_permitted_opens++; 2611 2612 all_opens_permitted = 0; 2613 } 2614 2615 void 2616 channel_clear_permitted_opens(void) 2617 { 2618 int i; 2619 2620 for (i = 0; i < num_permitted_opens; i++) 2621 if (permitted_opens[i].host_to_connect != NULL) 2622 xfree(permitted_opens[i].host_to_connect); 2623 num_permitted_opens = 0; 2624 2625 } 2626 2627 2628 /* return socket to remote host, port */ 2629 static int 2630 connect_to(const char *host, u_short port) 2631 { 2632 struct addrinfo hints, *ai, *aitop; 2633 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 2634 int gaierr; 2635 int sock = -1; 2636 2637 memset(&hints, 0, sizeof(hints)); 2638 hints.ai_family = IPv4or6; 2639 hints.ai_socktype = SOCK_STREAM; 2640 snprintf(strport, sizeof strport, "%d", port); 2641 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { 2642 error("connect_to %.100s: unknown host (%s)", host, 2643 gai_strerror(gaierr)); 2644 return -1; 2645 } 2646 for (ai = aitop; ai; ai = ai->ai_next) { 2647 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 2648 continue; 2649 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 2650 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 2651 error("connect_to: getnameinfo failed"); 2652 continue; 2653 } 2654 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 2655 if (sock < 0) { 2656 if (ai->ai_next == NULL) 2657 error("socket: %.100s", strerror(errno)); 2658 else 2659 verbose("socket: %.100s", strerror(errno)); 2660 continue; 2661 } 2662 if (set_nonblock(sock) == -1) 2663 fatal("%s: set_nonblock(%d)", __func__, sock); 2664 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 && 2665 errno != EINPROGRESS) { 2666 error("connect_to %.100s port %s: %.100s", ntop, strport, 2667 strerror(errno)); 2668 close(sock); 2669 continue; /* fail -- try next */ 2670 } 2671 break; /* success */ 2672 2673 } 2674 freeaddrinfo(aitop); 2675 if (!ai) { 2676 error("connect_to %.100s port %d: failed.", host, port); 2677 return -1; 2678 } 2679 /* success */ 2680 set_nodelay(sock); 2681 return sock; 2682 } 2683 2684 int 2685 channel_connect_by_listen_address(u_short listen_port) 2686 { 2687 int i; 2688 2689 for (i = 0; i < num_permitted_opens; i++) 2690 if (permitted_opens[i].host_to_connect != NULL && 2691 permitted_opens[i].listen_port == listen_port) 2692 return connect_to( 2693 permitted_opens[i].host_to_connect, 2694 permitted_opens[i].port_to_connect); 2695 error("WARNING: Server requests forwarding for unknown listen_port %d", 2696 listen_port); 2697 return -1; 2698 } 2699 2700 /* Check if connecting to that port is permitted and connect. */ 2701 int 2702 channel_connect_to(const char *host, u_short port) 2703 { 2704 int i, permit; 2705 2706 permit = all_opens_permitted; 2707 if (!permit) { 2708 for (i = 0; i < num_permitted_opens; i++) 2709 if (permitted_opens[i].host_to_connect != NULL && 2710 permitted_opens[i].port_to_connect == port && 2711 strcmp(permitted_opens[i].host_to_connect, host) == 0) 2712 permit = 1; 2713 2714 } 2715 if (!permit) { 2716 logit("Received request to connect to host %.100s port %d, " 2717 "but the request was denied.", host, port); 2718 return -1; 2719 } 2720 return connect_to(host, port); 2721 } 2722 2723 void 2724 channel_send_window_changes(void) 2725 { 2726 u_int i; 2727 struct winsize ws; 2728 2729 for (i = 0; i < channels_alloc; i++) { 2730 if (channels[i] == NULL || !channels[i]->client_tty || 2731 channels[i]->type != SSH_CHANNEL_OPEN) 2732 continue; 2733 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) 2734 continue; 2735 channel_request_start(i, "window-change", 0); 2736 packet_put_int(ws.ws_col); 2737 packet_put_int(ws.ws_row); 2738 packet_put_int(ws.ws_xpixel); 2739 packet_put_int(ws.ws_ypixel); 2740 packet_send(); 2741 } 2742 } 2743 2744 /* -- X11 forwarding */ 2745 2746 /* 2747 * Creates an internet domain socket for listening for X11 connections. 2748 * Returns 0 and a suitable display number for the DISPLAY variable 2749 * stored in display_numberp , or -1 if an error occurs. 2750 */ 2751 int 2752 x11_create_display_inet(int x11_display_offset, int x11_use_localhost, 2753 int single_connection, u_int *display_numberp, int **chanids) 2754 { 2755 Channel *nc = NULL; 2756 int display_number, sock; 2757 u_short port; 2758 struct addrinfo hints, *ai, *aitop; 2759 char strport[NI_MAXSERV]; 2760 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 2761 2762 if (chanids == NULL) 2763 return -1; 2764 2765 for (display_number = x11_display_offset; 2766 display_number < MAX_DISPLAYS; 2767 display_number++) { 2768 port = 6000 + display_number; 2769 memset(&hints, 0, sizeof(hints)); 2770 hints.ai_family = IPv4or6; 2771 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 2772 hints.ai_socktype = SOCK_STREAM; 2773 snprintf(strport, sizeof strport, "%d", port); 2774 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { 2775 error("getaddrinfo: %.100s", gai_strerror(gaierr)); 2776 return -1; 2777 } 2778 for (ai = aitop; ai; ai = ai->ai_next) { 2779 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 2780 continue; 2781 sock = socket(ai->ai_family, ai->ai_socktype, 2782 ai->ai_protocol); 2783 if (sock < 0) { 2784 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { 2785 error("socket: %.100s", strerror(errno)); 2786 freeaddrinfo(aitop); 2787 return -1; 2788 } else { 2789 debug("x11_create_display_inet: Socket family %d not supported", 2790 ai->ai_family); 2791 continue; 2792 } 2793 } 2794 #ifdef IPV6_V6ONLY 2795 if (ai->ai_family == AF_INET6) { 2796 int on = 1; 2797 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) 2798 error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno)); 2799 } 2800 #endif 2801 channel_set_reuseaddr(sock); 2802 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 2803 debug2("bind port %d: %.100s", port, strerror(errno)); 2804 close(sock); 2805 2806 if (ai->ai_next) 2807 continue; 2808 2809 for (n = 0; n < num_socks; n++) { 2810 close(socks[n]); 2811 } 2812 num_socks = 0; 2813 break; 2814 } 2815 socks[num_socks++] = sock; 2816 #ifndef DONT_TRY_OTHER_AF 2817 if (num_socks == NUM_SOCKS) 2818 break; 2819 #else 2820 if (x11_use_localhost) { 2821 if (num_socks == NUM_SOCKS) 2822 break; 2823 } else { 2824 break; 2825 } 2826 #endif 2827 } 2828 freeaddrinfo(aitop); 2829 if (num_socks > 0) 2830 break; 2831 } 2832 if (display_number >= MAX_DISPLAYS) { 2833 error("Failed to allocate internet-domain X11 display socket."); 2834 return -1; 2835 } 2836 /* Start listening for connections on the socket. */ 2837 for (n = 0; n < num_socks; n++) { 2838 sock = socks[n]; 2839 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 2840 error("listen: %.100s", strerror(errno)); 2841 close(sock); 2842 return -1; 2843 } 2844 } 2845 2846 /* Allocate a channel for each socket. */ 2847 *chanids = xmalloc(sizeof(**chanids) * (num_socks + 1)); 2848 for (n = 0; n < num_socks; n++) { 2849 sock = socks[n]; 2850 nc = channel_new("x11 listener", 2851 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 2852 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 2853 0, "X11 inet listener", 1); 2854 nc->single_connection = single_connection; 2855 (*chanids)[n] = nc->self; 2856 } 2857 (*chanids)[n] = -1; 2858 2859 /* Return the display number for the DISPLAY environment variable. */ 2860 *display_numberp = display_number; 2861 return (0); 2862 } 2863 2864 static int 2865 connect_local_xsocket(u_int dnr) 2866 { 2867 int sock; 2868 struct sockaddr_un addr; 2869 2870 sock = socket(AF_UNIX, SOCK_STREAM, 0); 2871 if (sock < 0) 2872 error("socket: %.100s", strerror(errno)); 2873 memset(&addr, 0, sizeof(addr)); 2874 addr.sun_family = AF_UNIX; 2875 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 2876 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0) 2877 return sock; 2878 close(sock); 2879 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 2880 return -1; 2881 } 2882 2883 int 2884 x11_connect_display(void) 2885 { 2886 int display_number, sock = 0; 2887 const char *display; 2888 char buf[1024], *cp; 2889 struct addrinfo hints, *ai, *aitop; 2890 char strport[NI_MAXSERV]; 2891 int gaierr; 2892 2893 /* Try to open a socket for the local X server. */ 2894 display = getenv("DISPLAY"); 2895 if (!display) { 2896 error("DISPLAY not set."); 2897 return -1; 2898 } 2899 /* 2900 * Now we decode the value of the DISPLAY variable and make a 2901 * connection to the real X server. 2902 */ 2903 2904 /* 2905 * Check if it is a unix domain socket. Unix domain displays are in 2906 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 2907 */ 2908 if (strncmp(display, "unix:", 5) == 0 || 2909 display[0] == ':') { 2910 /* Connect to the unix domain socket. */ 2911 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) { 2912 error("Could not parse display number from DISPLAY: %.100s", 2913 display); 2914 return -1; 2915 } 2916 /* Create a socket. */ 2917 sock = connect_local_xsocket(display_number); 2918 if (sock < 0) 2919 return -1; 2920 2921 /* OK, we now have a connection to the display. */ 2922 return sock; 2923 } 2924 /* 2925 * Connect to an inet socket. The DISPLAY value is supposedly 2926 * hostname:d[.s], where hostname may also be numeric IP address. 2927 */ 2928 strlcpy(buf, display, sizeof(buf)); 2929 cp = strchr(buf, ':'); 2930 if (!cp) { 2931 error("Could not find ':' in DISPLAY: %.100s", display); 2932 return -1; 2933 } 2934 *cp = 0; 2935 /* buf now contains the host name. But first we parse the display number. */ 2936 if (sscanf(cp + 1, "%d", &display_number) != 1) { 2937 error("Could not parse display number from DISPLAY: %.100s", 2938 display); 2939 return -1; 2940 } 2941 2942 /* Look up the host address */ 2943 memset(&hints, 0, sizeof(hints)); 2944 hints.ai_family = IPv4or6; 2945 hints.ai_socktype = SOCK_STREAM; 2946 snprintf(strport, sizeof strport, "%d", 6000 + display_number); 2947 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 2948 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr)); 2949 return -1; 2950 } 2951 for (ai = aitop; ai; ai = ai->ai_next) { 2952 /* Create a socket. */ 2953 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 2954 if (sock < 0) { 2955 debug2("socket: %.100s", strerror(errno)); 2956 continue; 2957 } 2958 /* Connect it to the display. */ 2959 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 2960 debug2("connect %.100s port %d: %.100s", buf, 2961 6000 + display_number, strerror(errno)); 2962 close(sock); 2963 continue; 2964 } 2965 /* Success */ 2966 break; 2967 } 2968 freeaddrinfo(aitop); 2969 if (!ai) { 2970 error("connect %.100s port %d: %.100s", buf, 6000 + display_number, 2971 strerror(errno)); 2972 return -1; 2973 } 2974 set_nodelay(sock); 2975 return sock; 2976 } 2977 2978 /* 2979 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains 2980 * the remote channel number. We should do whatever we want, and respond 2981 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. 2982 */ 2983 2984 void 2985 x11_input_open(int type, u_int32_t seq, void *ctxt) 2986 { 2987 Channel *c = NULL; 2988 int remote_id, sock = 0; 2989 char *remote_host; 2990 2991 debug("Received X11 open request."); 2992 2993 remote_id = packet_get_int(); 2994 2995 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 2996 remote_host = packet_get_string(NULL); 2997 } else { 2998 remote_host = xstrdup("unknown (remote did not supply name)"); 2999 } 3000 packet_check_eom(); 3001 3002 /* Obtain a connection to the real X display. */ 3003 sock = x11_connect_display(); 3004 if (sock != -1) { 3005 /* Allocate a channel for this connection. */ 3006 c = channel_new("connected x11 socket", 3007 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, 3008 remote_host, 1); 3009 c->remote_id = remote_id; 3010 c->force_drain = 1; 3011 } 3012 xfree(remote_host); 3013 if (c == NULL) { 3014 /* Send refusal to the remote host. */ 3015 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3016 packet_put_int(remote_id); 3017 } else { 3018 /* Send a confirmation to the remote host. */ 3019 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 3020 packet_put_int(remote_id); 3021 packet_put_int(c->self); 3022 } 3023 packet_send(); 3024 } 3025 3026 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ 3027 void 3028 deny_input_open(int type, u_int32_t seq, void *ctxt) 3029 { 3030 int rchan = packet_get_int(); 3031 3032 switch (type) { 3033 case SSH_SMSG_AGENT_OPEN: 3034 error("Warning: ssh server tried agent forwarding."); 3035 break; 3036 case SSH_SMSG_X11_OPEN: 3037 error("Warning: ssh server tried X11 forwarding."); 3038 break; 3039 default: 3040 error("deny_input_open: type %d", type); 3041 break; 3042 } 3043 error("Warning: this is probably a break-in attempt by a malicious server."); 3044 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 3045 packet_put_int(rchan); 3046 packet_send(); 3047 } 3048 3049 /* 3050 * Requests forwarding of X11 connections, generates fake authentication 3051 * data, and enables authentication spoofing. 3052 * This should be called in the client only. 3053 */ 3054 void 3055 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp, 3056 const char *proto, const char *data) 3057 { 3058 u_int data_len = (u_int) strlen(data) / 2; 3059 u_int i, value; 3060 char *new_data; 3061 int screen_number; 3062 const char *cp; 3063 u_int32_t rnd = 0; 3064 3065 if (x11_saved_display == NULL) 3066 x11_saved_display = xstrdup(disp); 3067 else if (strcmp(disp, x11_saved_display) != 0) { 3068 error("x11_request_forwarding_with_spoofing: different " 3069 "$DISPLAY already forwarded"); 3070 return; 3071 } 3072 3073 cp = disp; 3074 if (disp) 3075 cp = strchr(disp, ':'); 3076 if (cp) 3077 cp = strchr(cp, '.'); 3078 if (cp) 3079 screen_number = atoi(cp + 1); 3080 else 3081 screen_number = 0; 3082 3083 if (x11_saved_proto == NULL) { 3084 /* Save protocol name. */ 3085 x11_saved_proto = xstrdup(proto); 3086 /* 3087 * Extract real authentication data and generate fake data 3088 * of the same length. 3089 */ 3090 x11_saved_data = xmalloc(data_len); 3091 x11_fake_data = xmalloc(data_len); 3092 for (i = 0; i < data_len; i++) { 3093 if (sscanf(data + 2 * i, "%2x", &value) != 1) 3094 fatal("x11_request_forwarding: bad " 3095 "authentication data: %.100s", data); 3096 if (i % 4 == 0) 3097 rnd = arc4random(); 3098 x11_saved_data[i] = value; 3099 x11_fake_data[i] = rnd & 0xff; 3100 rnd >>= 8; 3101 } 3102 x11_saved_data_len = data_len; 3103 x11_fake_data_len = data_len; 3104 } 3105 3106 /* Convert the fake data into hex. */ 3107 new_data = tohex(x11_fake_data, data_len); 3108 3109 /* Send the request packet. */ 3110 if (compat20) { 3111 channel_request_start(client_session_id, "x11-req", 0); 3112 packet_put_char(0); /* XXX bool single connection */ 3113 } else { 3114 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); 3115 } 3116 packet_put_cstring(proto); 3117 packet_put_cstring(new_data); 3118 packet_put_int(screen_number); 3119 packet_send(); 3120 packet_write_wait(); 3121 xfree(new_data); 3122 } 3123 3124 3125 /* -- agent forwarding */ 3126 3127 /* Sends a message to the server to request authentication fd forwarding. */ 3128 3129 void 3130 auth_request_forwarding(void) 3131 { 3132 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); 3133 packet_send(); 3134 packet_write_wait(); 3135 } 3136