1 /* $OpenBSD: channels.c,v 1.353 2016/09/19 07:52:42 natano Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * This file contains functions for generic socket connection forwarding. 7 * There is also code for initiating connection forwarding for X11 connections, 8 * arbitrary tcp/ip connections, and the authentication agent connection. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 support added by Markus Friedl. 17 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 18 * Copyright (c) 1999 Dug Song. All rights reserved. 19 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 40 */ 41 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 #include <sys/ioctl.h> 45 #include <sys/un.h> 46 #include <sys/socket.h> 47 #include <sys/time.h> 48 #include <sys/queue.h> 49 50 #include <netinet/in.h> 51 #include <arpa/inet.h> 52 53 #include <errno.h> 54 #include <fcntl.h> 55 #include <netdb.h> 56 #include <stdint.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 #include <termios.h> 61 #include <unistd.h> 62 #include <stdarg.h> 63 64 #include "xmalloc.h" 65 #include "ssh.h" 66 #include "ssh1.h" 67 #include "ssh2.h" 68 #include "packet.h" 69 #include "log.h" 70 #include "misc.h" 71 #include "buffer.h" 72 #include "channels.h" 73 #include "compat.h" 74 #include "canohost.h" 75 #include "key.h" 76 #include "authfd.h" 77 #include "pathnames.h" 78 79 /* -- channel core */ 80 81 /* 82 * Pointer to an array containing all allocated channels. The array is 83 * dynamically extended as needed. 84 */ 85 static Channel **channels = NULL; 86 87 /* 88 * Size of the channel array. All slots of the array must always be 89 * initialized (at least the type field); unused slots set to NULL 90 */ 91 static u_int channels_alloc = 0; 92 93 /* 94 * Maximum file descriptor value used in any of the channels. This is 95 * updated in channel_new. 96 */ 97 static int channel_max_fd = 0; 98 99 100 /* -- tcp forwarding */ 101 102 /* 103 * Data structure for storing which hosts are permitted for forward requests. 104 * The local sides of any remote forwards are stored in this array to prevent 105 * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 106 * network (which might be behind a firewall). 107 */ 108 /* XXX: streamlocal wants a path instead of host:port */ 109 /* Overload host_to_connect; we could just make this match Forward */ 110 /* XXX - can we use listen_host instead of listen_path? */ 111 typedef struct { 112 char *host_to_connect; /* Connect to 'host'. */ 113 int port_to_connect; /* Connect to 'port'. */ 114 char *listen_host; /* Remote side should listen address. */ 115 char *listen_path; /* Remote side should listen path. */ 116 int listen_port; /* Remote side should listen port. */ 117 } ForwardPermission; 118 119 /* List of all permitted host/port pairs to connect by the user. */ 120 static ForwardPermission *permitted_opens = NULL; 121 122 /* List of all permitted host/port pairs to connect by the admin. */ 123 static ForwardPermission *permitted_adm_opens = NULL; 124 125 /* Number of permitted host/port pairs in the array permitted by the user. */ 126 static int num_permitted_opens = 0; 127 128 /* Number of permitted host/port pair in the array permitted by the admin. */ 129 static int num_adm_permitted_opens = 0; 130 131 /* special-case port number meaning allow any port */ 132 #define FWD_PERMIT_ANY_PORT 0 133 134 /* special-case wildcard meaning allow any host */ 135 #define FWD_PERMIT_ANY_HOST "*" 136 137 /* 138 * If this is true, all opens are permitted. This is the case on the server 139 * on which we have to trust the client anyway, and the user could do 140 * anything after logging in anyway. 141 */ 142 static int all_opens_permitted = 0; 143 144 145 /* -- X11 forwarding */ 146 147 /* Maximum number of fake X11 displays to try. */ 148 #define MAX_DISPLAYS 1000 149 150 /* Saved X11 local (client) display. */ 151 static char *x11_saved_display = NULL; 152 153 /* Saved X11 authentication protocol name. */ 154 static char *x11_saved_proto = NULL; 155 156 /* Saved X11 authentication data. This is the real data. */ 157 static char *x11_saved_data = NULL; 158 static u_int x11_saved_data_len = 0; 159 160 /* Deadline after which all X11 connections are refused */ 161 static u_int x11_refuse_time; 162 163 /* 164 * Fake X11 authentication data. This is what the server will be sending us; 165 * we should replace any occurrences of this by the real data. 166 */ 167 static u_char *x11_fake_data = NULL; 168 static u_int x11_fake_data_len; 169 170 171 /* -- agent forwarding */ 172 173 #define NUM_SOCKS 10 174 175 /* AF_UNSPEC or AF_INET or AF_INET6 */ 176 static int IPv4or6 = AF_UNSPEC; 177 178 /* helper */ 179 static void port_open_helper(Channel *c, char *rtype); 180 181 /* non-blocking connect helpers */ 182 static int connect_next(struct channel_connect *); 183 static void channel_connect_ctx_free(struct channel_connect *); 184 185 /* -- channel core */ 186 187 Channel * 188 channel_by_id(int id) 189 { 190 Channel *c; 191 192 if (id < 0 || (u_int)id >= channels_alloc) { 193 logit("channel_by_id: %d: bad id", id); 194 return NULL; 195 } 196 c = channels[id]; 197 if (c == NULL) { 198 logit("channel_by_id: %d: bad id: channel free", id); 199 return NULL; 200 } 201 return c; 202 } 203 204 /* 205 * Returns the channel if it is allowed to receive protocol messages. 206 * Private channels, like listening sockets, may not receive messages. 207 */ 208 Channel * 209 channel_lookup(int id) 210 { 211 Channel *c; 212 213 if ((c = channel_by_id(id)) == NULL) 214 return (NULL); 215 216 switch (c->type) { 217 case SSH_CHANNEL_X11_OPEN: 218 case SSH_CHANNEL_LARVAL: 219 case SSH_CHANNEL_CONNECTING: 220 case SSH_CHANNEL_DYNAMIC: 221 case SSH_CHANNEL_OPENING: 222 case SSH_CHANNEL_OPEN: 223 case SSH_CHANNEL_INPUT_DRAINING: 224 case SSH_CHANNEL_OUTPUT_DRAINING: 225 case SSH_CHANNEL_ABANDONED: 226 return (c); 227 } 228 logit("Non-public channel %d, type %d.", id, c->type); 229 return (NULL); 230 } 231 232 /* 233 * Register filedescriptors for a channel, used when allocating a channel or 234 * when the channel consumer/producer is ready, e.g. shell exec'd 235 */ 236 static void 237 channel_register_fds(Channel *c, int rfd, int wfd, int efd, 238 int extusage, int nonblock, int is_tty) 239 { 240 /* Update the maximum file descriptor value. */ 241 channel_max_fd = MAXIMUM(channel_max_fd, rfd); 242 channel_max_fd = MAXIMUM(channel_max_fd, wfd); 243 channel_max_fd = MAXIMUM(channel_max_fd, efd); 244 245 if (rfd != -1) 246 fcntl(rfd, F_SETFD, FD_CLOEXEC); 247 if (wfd != -1 && wfd != rfd) 248 fcntl(wfd, F_SETFD, FD_CLOEXEC); 249 if (efd != -1 && efd != rfd && efd != wfd) 250 fcntl(efd, F_SETFD, FD_CLOEXEC); 251 252 c->rfd = rfd; 253 c->wfd = wfd; 254 c->sock = (rfd == wfd) ? rfd : -1; 255 c->efd = efd; 256 c->extended_usage = extusage; 257 258 if ((c->isatty = is_tty) != 0) 259 debug2("channel %d: rfd %d isatty", c->self, c->rfd); 260 261 /* enable nonblocking mode */ 262 if (nonblock) { 263 if (rfd != -1) 264 set_nonblock(rfd); 265 if (wfd != -1) 266 set_nonblock(wfd); 267 if (efd != -1) 268 set_nonblock(efd); 269 } 270 } 271 272 /* 273 * Allocate a new channel object and set its type and socket. This will cause 274 * remote_name to be freed. 275 */ 276 Channel * 277 channel_new(char *ctype, int type, int rfd, int wfd, int efd, 278 u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) 279 { 280 int found; 281 u_int i; 282 Channel *c; 283 284 /* Do initial allocation if this is the first call. */ 285 if (channels_alloc == 0) { 286 channels_alloc = 10; 287 channels = xcalloc(channels_alloc, sizeof(Channel *)); 288 for (i = 0; i < channels_alloc; i++) 289 channels[i] = NULL; 290 } 291 /* Try to find a free slot where to put the new channel. */ 292 for (found = -1, i = 0; i < channels_alloc; i++) 293 if (channels[i] == NULL) { 294 /* Found a free slot. */ 295 found = (int)i; 296 break; 297 } 298 if (found < 0) { 299 /* There are no free slots. Take last+1 slot and expand the array. */ 300 found = channels_alloc; 301 if (channels_alloc > 10000) 302 fatal("channel_new: internal error: channels_alloc %d " 303 "too big.", channels_alloc); 304 channels = xreallocarray(channels, channels_alloc + 10, 305 sizeof(Channel *)); 306 channels_alloc += 10; 307 debug2("channel: expanding %d", channels_alloc); 308 for (i = found; i < channels_alloc; i++) 309 channels[i] = NULL; 310 } 311 /* Initialize and return new channel. */ 312 c = channels[found] = xcalloc(1, sizeof(Channel)); 313 buffer_init(&c->input); 314 buffer_init(&c->output); 315 buffer_init(&c->extended); 316 c->path = NULL; 317 c->listening_addr = NULL; 318 c->listening_port = 0; 319 c->ostate = CHAN_OUTPUT_OPEN; 320 c->istate = CHAN_INPUT_OPEN; 321 c->flags = 0; 322 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0); 323 c->notbefore = 0; 324 c->self = found; 325 c->type = type; 326 c->ctype = ctype; 327 c->local_window = window; 328 c->local_window_max = window; 329 c->local_consumed = 0; 330 c->local_maxpacket = maxpack; 331 c->remote_id = -1; 332 c->remote_name = xstrdup(remote_name); 333 c->remote_window = 0; 334 c->remote_maxpacket = 0; 335 c->force_drain = 0; 336 c->single_connection = 0; 337 c->detach_user = NULL; 338 c->detach_close = 0; 339 c->open_confirm = NULL; 340 c->open_confirm_ctx = NULL; 341 c->input_filter = NULL; 342 c->output_filter = NULL; 343 c->filter_ctx = NULL; 344 c->filter_cleanup = NULL; 345 c->ctl_chan = -1; 346 c->mux_rcb = NULL; 347 c->mux_ctx = NULL; 348 c->mux_pause = 0; 349 c->delayed = 1; /* prevent call to channel_post handler */ 350 TAILQ_INIT(&c->status_confirms); 351 debug("channel %d: new [%s]", found, remote_name); 352 return c; 353 } 354 355 static int 356 channel_find_maxfd(void) 357 { 358 u_int i; 359 int max = 0; 360 Channel *c; 361 362 for (i = 0; i < channels_alloc; i++) { 363 c = channels[i]; 364 if (c != NULL) { 365 max = MAXIMUM(max, c->rfd); 366 max = MAXIMUM(max, c->wfd); 367 max = MAXIMUM(max, c->efd); 368 } 369 } 370 return max; 371 } 372 373 int 374 channel_close_fd(int *fdp) 375 { 376 int ret = 0, fd = *fdp; 377 378 if (fd != -1) { 379 ret = close(fd); 380 *fdp = -1; 381 if (fd == channel_max_fd) 382 channel_max_fd = channel_find_maxfd(); 383 } 384 return ret; 385 } 386 387 /* Close all channel fd/socket. */ 388 static void 389 channel_close_fds(Channel *c) 390 { 391 channel_close_fd(&c->sock); 392 channel_close_fd(&c->rfd); 393 channel_close_fd(&c->wfd); 394 channel_close_fd(&c->efd); 395 } 396 397 /* Free the channel and close its fd/socket. */ 398 void 399 channel_free(Channel *c) 400 { 401 char *s; 402 u_int i, n; 403 struct channel_confirm *cc; 404 405 for (n = 0, i = 0; i < channels_alloc; i++) 406 if (channels[i]) 407 n++; 408 debug("channel %d: free: %s, nchannels %u", c->self, 409 c->remote_name ? c->remote_name : "???", n); 410 411 s = channel_open_message(); 412 debug3("channel %d: status: %s", c->self, s); 413 free(s); 414 415 if (c->sock != -1) 416 shutdown(c->sock, SHUT_RDWR); 417 channel_close_fds(c); 418 buffer_free(&c->input); 419 buffer_free(&c->output); 420 buffer_free(&c->extended); 421 free(c->remote_name); 422 c->remote_name = NULL; 423 free(c->path); 424 c->path = NULL; 425 free(c->listening_addr); 426 c->listening_addr = NULL; 427 while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { 428 if (cc->abandon_cb != NULL) 429 cc->abandon_cb(c, cc->ctx); 430 TAILQ_REMOVE(&c->status_confirms, cc, entry); 431 explicit_bzero(cc, sizeof(*cc)); 432 free(cc); 433 } 434 if (c->filter_cleanup != NULL && c->filter_ctx != NULL) 435 c->filter_cleanup(c->self, c->filter_ctx); 436 channels[c->self] = NULL; 437 free(c); 438 } 439 440 void 441 channel_free_all(void) 442 { 443 u_int i; 444 445 for (i = 0; i < channels_alloc; i++) 446 if (channels[i] != NULL) 447 channel_free(channels[i]); 448 } 449 450 /* 451 * Closes the sockets/fds of all channels. This is used to close extra file 452 * descriptors after a fork. 453 */ 454 void 455 channel_close_all(void) 456 { 457 u_int i; 458 459 for (i = 0; i < channels_alloc; i++) 460 if (channels[i] != NULL) 461 channel_close_fds(channels[i]); 462 } 463 464 /* 465 * Stop listening to channels. 466 */ 467 void 468 channel_stop_listening(void) 469 { 470 u_int i; 471 Channel *c; 472 473 for (i = 0; i < channels_alloc; i++) { 474 c = channels[i]; 475 if (c != NULL) { 476 switch (c->type) { 477 case SSH_CHANNEL_AUTH_SOCKET: 478 case SSH_CHANNEL_PORT_LISTENER: 479 case SSH_CHANNEL_RPORT_LISTENER: 480 case SSH_CHANNEL_X11_LISTENER: 481 case SSH_CHANNEL_UNIX_LISTENER: 482 case SSH_CHANNEL_RUNIX_LISTENER: 483 channel_close_fd(&c->sock); 484 channel_free(c); 485 break; 486 } 487 } 488 } 489 } 490 491 /* 492 * Returns true if no channel has too much buffered data, and false if one or 493 * more channel is overfull. 494 */ 495 int 496 channel_not_very_much_buffered_data(void) 497 { 498 u_int i; 499 Channel *c; 500 501 for (i = 0; i < channels_alloc; i++) { 502 c = channels[i]; 503 if (c != NULL && c->type == SSH_CHANNEL_OPEN) { 504 #if 0 505 if (!compat20 && 506 buffer_len(&c->input) > packet_get_maxsize()) { 507 debug2("channel %d: big input buffer %d", 508 c->self, buffer_len(&c->input)); 509 return 0; 510 } 511 #endif 512 if (buffer_len(&c->output) > packet_get_maxsize()) { 513 debug2("channel %d: big output buffer %u > %u", 514 c->self, buffer_len(&c->output), 515 packet_get_maxsize()); 516 return 0; 517 } 518 } 519 } 520 return 1; 521 } 522 523 /* Returns true if any channel is still open. */ 524 int 525 channel_still_open(void) 526 { 527 u_int i; 528 Channel *c; 529 530 for (i = 0; i < channels_alloc; i++) { 531 c = channels[i]; 532 if (c == NULL) 533 continue; 534 switch (c->type) { 535 case SSH_CHANNEL_X11_LISTENER: 536 case SSH_CHANNEL_PORT_LISTENER: 537 case SSH_CHANNEL_RPORT_LISTENER: 538 case SSH_CHANNEL_MUX_LISTENER: 539 case SSH_CHANNEL_CLOSED: 540 case SSH_CHANNEL_AUTH_SOCKET: 541 case SSH_CHANNEL_DYNAMIC: 542 case SSH_CHANNEL_CONNECTING: 543 case SSH_CHANNEL_ZOMBIE: 544 case SSH_CHANNEL_ABANDONED: 545 case SSH_CHANNEL_UNIX_LISTENER: 546 case SSH_CHANNEL_RUNIX_LISTENER: 547 continue; 548 case SSH_CHANNEL_LARVAL: 549 if (!compat20) 550 fatal("cannot happen: SSH_CHANNEL_LARVAL"); 551 continue; 552 case SSH_CHANNEL_OPENING: 553 case SSH_CHANNEL_OPEN: 554 case SSH_CHANNEL_X11_OPEN: 555 case SSH_CHANNEL_MUX_CLIENT: 556 return 1; 557 case SSH_CHANNEL_INPUT_DRAINING: 558 case SSH_CHANNEL_OUTPUT_DRAINING: 559 if (!compat13) 560 fatal("cannot happen: OUT_DRAIN"); 561 return 1; 562 default: 563 fatal("channel_still_open: bad channel type %d", c->type); 564 /* NOTREACHED */ 565 } 566 } 567 return 0; 568 } 569 570 /* Returns the id of an open channel suitable for keepaliving */ 571 int 572 channel_find_open(void) 573 { 574 u_int i; 575 Channel *c; 576 577 for (i = 0; i < channels_alloc; i++) { 578 c = channels[i]; 579 if (c == NULL || c->remote_id < 0) 580 continue; 581 switch (c->type) { 582 case SSH_CHANNEL_CLOSED: 583 case SSH_CHANNEL_DYNAMIC: 584 case SSH_CHANNEL_X11_LISTENER: 585 case SSH_CHANNEL_PORT_LISTENER: 586 case SSH_CHANNEL_RPORT_LISTENER: 587 case SSH_CHANNEL_MUX_LISTENER: 588 case SSH_CHANNEL_MUX_CLIENT: 589 case SSH_CHANNEL_OPENING: 590 case SSH_CHANNEL_CONNECTING: 591 case SSH_CHANNEL_ZOMBIE: 592 case SSH_CHANNEL_ABANDONED: 593 case SSH_CHANNEL_UNIX_LISTENER: 594 case SSH_CHANNEL_RUNIX_LISTENER: 595 continue; 596 case SSH_CHANNEL_LARVAL: 597 case SSH_CHANNEL_AUTH_SOCKET: 598 case SSH_CHANNEL_OPEN: 599 case SSH_CHANNEL_X11_OPEN: 600 return i; 601 case SSH_CHANNEL_INPUT_DRAINING: 602 case SSH_CHANNEL_OUTPUT_DRAINING: 603 if (!compat13) 604 fatal("cannot happen: OUT_DRAIN"); 605 return i; 606 default: 607 fatal("channel_find_open: bad channel type %d", c->type); 608 /* NOTREACHED */ 609 } 610 } 611 return -1; 612 } 613 614 615 /* 616 * Returns a message describing the currently open forwarded connections, 617 * suitable for sending to the client. The message contains crlf pairs for 618 * newlines. 619 */ 620 char * 621 channel_open_message(void) 622 { 623 Buffer buffer; 624 Channel *c; 625 char buf[1024], *cp; 626 u_int i; 627 628 buffer_init(&buffer); 629 snprintf(buf, sizeof buf, "The following connections are open:\r\n"); 630 buffer_append(&buffer, buf, strlen(buf)); 631 for (i = 0; i < channels_alloc; i++) { 632 c = channels[i]; 633 if (c == NULL) 634 continue; 635 switch (c->type) { 636 case SSH_CHANNEL_X11_LISTENER: 637 case SSH_CHANNEL_PORT_LISTENER: 638 case SSH_CHANNEL_RPORT_LISTENER: 639 case SSH_CHANNEL_CLOSED: 640 case SSH_CHANNEL_AUTH_SOCKET: 641 case SSH_CHANNEL_ZOMBIE: 642 case SSH_CHANNEL_ABANDONED: 643 case SSH_CHANNEL_MUX_CLIENT: 644 case SSH_CHANNEL_MUX_LISTENER: 645 case SSH_CHANNEL_UNIX_LISTENER: 646 case SSH_CHANNEL_RUNIX_LISTENER: 647 continue; 648 case SSH_CHANNEL_LARVAL: 649 case SSH_CHANNEL_OPENING: 650 case SSH_CHANNEL_CONNECTING: 651 case SSH_CHANNEL_DYNAMIC: 652 case SSH_CHANNEL_OPEN: 653 case SSH_CHANNEL_X11_OPEN: 654 case SSH_CHANNEL_INPUT_DRAINING: 655 case SSH_CHANNEL_OUTPUT_DRAINING: 656 snprintf(buf, sizeof buf, 657 " #%d %.300s (t%d r%d i%u/%d o%u/%d fd %d/%d cc %d)\r\n", 658 c->self, c->remote_name, 659 c->type, c->remote_id, 660 c->istate, buffer_len(&c->input), 661 c->ostate, buffer_len(&c->output), 662 c->rfd, c->wfd, c->ctl_chan); 663 buffer_append(&buffer, buf, strlen(buf)); 664 continue; 665 default: 666 fatal("channel_open_message: bad channel type %d", c->type); 667 /* NOTREACHED */ 668 } 669 } 670 buffer_append(&buffer, "\0", 1); 671 cp = xstrdup((char *)buffer_ptr(&buffer)); 672 buffer_free(&buffer); 673 return cp; 674 } 675 676 void 677 channel_send_open(int id) 678 { 679 Channel *c = channel_lookup(id); 680 681 if (c == NULL) { 682 logit("channel_send_open: %d: bad id", id); 683 return; 684 } 685 debug2("channel %d: send open", id); 686 packet_start(SSH2_MSG_CHANNEL_OPEN); 687 packet_put_cstring(c->ctype); 688 packet_put_int(c->self); 689 packet_put_int(c->local_window); 690 packet_put_int(c->local_maxpacket); 691 packet_send(); 692 } 693 694 void 695 channel_request_start(int id, char *service, int wantconfirm) 696 { 697 Channel *c = channel_lookup(id); 698 699 if (c == NULL) { 700 logit("channel_request_start: %d: unknown channel id", id); 701 return; 702 } 703 debug2("channel %d: request %s confirm %d", id, service, wantconfirm); 704 packet_start(SSH2_MSG_CHANNEL_REQUEST); 705 packet_put_int(c->remote_id); 706 packet_put_cstring(service); 707 packet_put_char(wantconfirm); 708 } 709 710 void 711 channel_register_status_confirm(int id, channel_confirm_cb *cb, 712 channel_confirm_abandon_cb *abandon_cb, void *ctx) 713 { 714 struct channel_confirm *cc; 715 Channel *c; 716 717 if ((c = channel_lookup(id)) == NULL) 718 fatal("channel_register_expect: %d: bad id", id); 719 720 cc = xcalloc(1, sizeof(*cc)); 721 cc->cb = cb; 722 cc->abandon_cb = abandon_cb; 723 cc->ctx = ctx; 724 TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); 725 } 726 727 void 728 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx) 729 { 730 Channel *c = channel_lookup(id); 731 732 if (c == NULL) { 733 logit("channel_register_open_confirm: %d: bad id", id); 734 return; 735 } 736 c->open_confirm = fn; 737 c->open_confirm_ctx = ctx; 738 } 739 740 void 741 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close) 742 { 743 Channel *c = channel_by_id(id); 744 745 if (c == NULL) { 746 logit("channel_register_cleanup: %d: bad id", id); 747 return; 748 } 749 c->detach_user = fn; 750 c->detach_close = do_close; 751 } 752 753 void 754 channel_cancel_cleanup(int id) 755 { 756 Channel *c = channel_by_id(id); 757 758 if (c == NULL) { 759 logit("channel_cancel_cleanup: %d: bad id", id); 760 return; 761 } 762 c->detach_user = NULL; 763 c->detach_close = 0; 764 } 765 766 void 767 channel_register_filter(int id, channel_infilter_fn *ifn, 768 channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) 769 { 770 Channel *c = channel_lookup(id); 771 772 if (c == NULL) { 773 logit("channel_register_filter: %d: bad id", id); 774 return; 775 } 776 c->input_filter = ifn; 777 c->output_filter = ofn; 778 c->filter_ctx = ctx; 779 c->filter_cleanup = cfn; 780 } 781 782 void 783 channel_set_fds(int id, int rfd, int wfd, int efd, 784 int extusage, int nonblock, int is_tty, u_int window_max) 785 { 786 Channel *c = channel_lookup(id); 787 788 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 789 fatal("channel_activate for non-larval channel %d.", id); 790 channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty); 791 c->type = SSH_CHANNEL_OPEN; 792 c->local_window = c->local_window_max = window_max; 793 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 794 packet_put_int(c->remote_id); 795 packet_put_int(c->local_window); 796 packet_send(); 797 } 798 799 /* 800 * 'channel_pre*' are called just before select() to add any bits relevant to 801 * channels in the select bitmasks. 802 */ 803 /* 804 * 'channel_post*': perform any appropriate operations for channels which 805 * have events pending. 806 */ 807 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset); 808 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; 809 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; 810 811 /* ARGSUSED */ 812 static void 813 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset) 814 { 815 FD_SET(c->sock, readset); 816 } 817 818 /* ARGSUSED */ 819 static void 820 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset) 821 { 822 debug3("channel %d: waiting for connection", c->self); 823 FD_SET(c->sock, writeset); 824 } 825 826 static void 827 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset) 828 { 829 if (buffer_len(&c->input) < packet_get_maxsize()) 830 FD_SET(c->sock, readset); 831 if (buffer_len(&c->output) > 0) 832 FD_SET(c->sock, writeset); 833 } 834 835 static void 836 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset) 837 { 838 u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); 839 840 if (c->istate == CHAN_INPUT_OPEN && 841 limit > 0 && 842 buffer_len(&c->input) < limit && 843 buffer_check_alloc(&c->input, CHAN_RBUF)) 844 FD_SET(c->rfd, readset); 845 if (c->ostate == CHAN_OUTPUT_OPEN || 846 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 847 if (buffer_len(&c->output) > 0) { 848 FD_SET(c->wfd, writeset); 849 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 850 if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) 851 debug2("channel %d: obuf_empty delayed efd %d/(%d)", 852 c->self, c->efd, buffer_len(&c->extended)); 853 else 854 chan_obuf_empty(c); 855 } 856 } 857 /** XXX check close conditions, too */ 858 if (compat20 && c->efd != -1 && 859 !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) { 860 if (c->extended_usage == CHAN_EXTENDED_WRITE && 861 buffer_len(&c->extended) > 0) 862 FD_SET(c->efd, writeset); 863 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && 864 (c->extended_usage == CHAN_EXTENDED_READ || 865 c->extended_usage == CHAN_EXTENDED_IGNORE) && 866 buffer_len(&c->extended) < c->remote_window) 867 FD_SET(c->efd, readset); 868 } 869 /* XXX: What about efd? races? */ 870 } 871 872 /* ARGSUSED */ 873 static void 874 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset) 875 { 876 if (buffer_len(&c->input) == 0) { 877 packet_start(SSH_MSG_CHANNEL_CLOSE); 878 packet_put_int(c->remote_id); 879 packet_send(); 880 c->type = SSH_CHANNEL_CLOSED; 881 debug2("channel %d: closing after input drain.", c->self); 882 } 883 } 884 885 /* ARGSUSED */ 886 static void 887 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset) 888 { 889 if (buffer_len(&c->output) == 0) 890 chan_mark_dead(c); 891 else 892 FD_SET(c->sock, writeset); 893 } 894 895 /* 896 * This is a special state for X11 authentication spoofing. An opened X11 897 * connection (when authentication spoofing is being done) remains in this 898 * state until the first packet has been completely read. The authentication 899 * data in that packet is then substituted by the real data if it matches the 900 * fake data, and the channel is put into normal mode. 901 * XXX All this happens at the client side. 902 * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok 903 */ 904 static int 905 x11_open_helper(Buffer *b) 906 { 907 u_char *ucp; 908 u_int proto_len, data_len; 909 910 /* Is this being called after the refusal deadline? */ 911 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 912 verbose("Rejected X11 connection after ForwardX11Timeout " 913 "expired"); 914 return -1; 915 } 916 917 /* Check if the fixed size part of the packet is in buffer. */ 918 if (buffer_len(b) < 12) 919 return 0; 920 921 /* Parse the lengths of variable-length fields. */ 922 ucp = buffer_ptr(b); 923 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 924 proto_len = 256 * ucp[6] + ucp[7]; 925 data_len = 256 * ucp[8] + ucp[9]; 926 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 927 proto_len = ucp[6] + 256 * ucp[7]; 928 data_len = ucp[8] + 256 * ucp[9]; 929 } else { 930 debug2("Initial X11 packet contains bad byte order byte: 0x%x", 931 ucp[0]); 932 return -1; 933 } 934 935 /* Check if the whole packet is in buffer. */ 936 if (buffer_len(b) < 937 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 938 return 0; 939 940 /* Check if authentication protocol matches. */ 941 if (proto_len != strlen(x11_saved_proto) || 942 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { 943 debug2("X11 connection uses different authentication protocol."); 944 return -1; 945 } 946 /* Check if authentication data matches our fake data. */ 947 if (data_len != x11_fake_data_len || 948 timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), 949 x11_fake_data, x11_fake_data_len) != 0) { 950 debug2("X11 auth data does not match fake data."); 951 return -1; 952 } 953 /* Check fake data length */ 954 if (x11_fake_data_len != x11_saved_data_len) { 955 error("X11 fake_data_len %d != saved_data_len %d", 956 x11_fake_data_len, x11_saved_data_len); 957 return -1; 958 } 959 /* 960 * Received authentication protocol and data match 961 * our fake data. Substitute the fake data with real 962 * data. 963 */ 964 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 965 x11_saved_data, x11_saved_data_len); 966 return 1; 967 } 968 969 static void 970 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset) 971 { 972 int ret = x11_open_helper(&c->output); 973 974 if (ret == 1) { 975 /* Start normal processing for the channel. */ 976 c->type = SSH_CHANNEL_OPEN; 977 channel_pre_open_13(c, readset, writeset); 978 } else if (ret == -1) { 979 /* 980 * We have received an X11 connection that has bad 981 * authentication information. 982 */ 983 logit("X11 connection rejected because of wrong authentication."); 984 buffer_clear(&c->input); 985 buffer_clear(&c->output); 986 channel_close_fd(&c->sock); 987 c->sock = -1; 988 c->type = SSH_CHANNEL_CLOSED; 989 packet_start(SSH_MSG_CHANNEL_CLOSE); 990 packet_put_int(c->remote_id); 991 packet_send(); 992 } 993 } 994 995 static void 996 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset) 997 { 998 int ret = x11_open_helper(&c->output); 999 1000 /* c->force_drain = 1; */ 1001 1002 if (ret == 1) { 1003 c->type = SSH_CHANNEL_OPEN; 1004 channel_pre_open(c, readset, writeset); 1005 } else if (ret == -1) { 1006 logit("X11 connection rejected because of wrong authentication."); 1007 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); 1008 chan_read_failed(c); 1009 buffer_clear(&c->input); 1010 chan_ibuf_empty(c); 1011 buffer_clear(&c->output); 1012 /* for proto v1, the peer will send an IEOF */ 1013 if (compat20) 1014 chan_write_failed(c); 1015 else 1016 c->type = SSH_CHANNEL_OPEN; 1017 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 1018 } 1019 } 1020 1021 static void 1022 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1023 { 1024 if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && 1025 buffer_check_alloc(&c->input, CHAN_RBUF)) 1026 FD_SET(c->rfd, readset); 1027 if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 1028 /* clear buffer immediately (discard any partial packet) */ 1029 buffer_clear(&c->input); 1030 chan_ibuf_empty(c); 1031 /* Start output drain. XXX just kill chan? */ 1032 chan_rcvd_oclose(c); 1033 } 1034 if (c->ostate == CHAN_OUTPUT_OPEN || 1035 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 1036 if (buffer_len(&c->output) > 0) 1037 FD_SET(c->wfd, writeset); 1038 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) 1039 chan_obuf_empty(c); 1040 } 1041 } 1042 1043 /* try to decode a socks4 header */ 1044 /* ARGSUSED */ 1045 static int 1046 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset) 1047 { 1048 char *p, *host; 1049 u_int len, have, i, found, need; 1050 char username[256]; 1051 struct { 1052 u_int8_t version; 1053 u_int8_t command; 1054 u_int16_t dest_port; 1055 struct in_addr dest_addr; 1056 } s4_req, s4_rsp; 1057 1058 debug2("channel %d: decode socks4", c->self); 1059 1060 have = buffer_len(&c->input); 1061 len = sizeof(s4_req); 1062 if (have < len) 1063 return 0; 1064 p = (char *)buffer_ptr(&c->input); 1065 1066 need = 1; 1067 /* SOCKS4A uses an invalid IP address 0.0.0.x */ 1068 if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) { 1069 debug2("channel %d: socks4a request", c->self); 1070 /* ... and needs an extra string (the hostname) */ 1071 need = 2; 1072 } 1073 /* Check for terminating NUL on the string(s) */ 1074 for (found = 0, i = len; i < have; i++) { 1075 if (p[i] == '\0') { 1076 found++; 1077 if (found == need) 1078 break; 1079 } 1080 if (i > 1024) { 1081 /* the peer is probably sending garbage */ 1082 debug("channel %d: decode socks4: too long", 1083 c->self); 1084 return -1; 1085 } 1086 } 1087 if (found < need) 1088 return 0; 1089 buffer_get(&c->input, (char *)&s4_req.version, 1); 1090 buffer_get(&c->input, (char *)&s4_req.command, 1); 1091 buffer_get(&c->input, (char *)&s4_req.dest_port, 2); 1092 buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); 1093 have = buffer_len(&c->input); 1094 p = (char *)buffer_ptr(&c->input); 1095 if (memchr(p, '\0', have) == NULL) 1096 fatal("channel %d: decode socks4: user not nul terminated", 1097 c->self); 1098 len = strlen(p); 1099 debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); 1100 len++; /* trailing '\0' */ 1101 if (len > have) 1102 fatal("channel %d: decode socks4: len %d > have %d", 1103 c->self, len, have); 1104 strlcpy(username, p, sizeof(username)); 1105 buffer_consume(&c->input, len); 1106 1107 free(c->path); 1108 c->path = NULL; 1109 if (need == 1) { /* SOCKS4: one string */ 1110 host = inet_ntoa(s4_req.dest_addr); 1111 c->path = xstrdup(host); 1112 } else { /* SOCKS4A: two strings */ 1113 have = buffer_len(&c->input); 1114 p = (char *)buffer_ptr(&c->input); 1115 len = strlen(p); 1116 debug2("channel %d: decode socks4a: host %s/%d", 1117 c->self, p, len); 1118 len++; /* trailing '\0' */ 1119 if (len > have) 1120 fatal("channel %d: decode socks4a: len %d > have %d", 1121 c->self, len, have); 1122 if (len > NI_MAXHOST) { 1123 error("channel %d: hostname \"%.100s\" too long", 1124 c->self, p); 1125 return -1; 1126 } 1127 c->path = xstrdup(p); 1128 buffer_consume(&c->input, len); 1129 } 1130 c->host_port = ntohs(s4_req.dest_port); 1131 1132 debug2("channel %d: dynamic request: socks4 host %s port %u command %u", 1133 c->self, c->path, c->host_port, s4_req.command); 1134 1135 if (s4_req.command != 1) { 1136 debug("channel %d: cannot handle: %s cn %d", 1137 c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command); 1138 return -1; 1139 } 1140 s4_rsp.version = 0; /* vn: 0 for reply */ 1141 s4_rsp.command = 90; /* cd: req granted */ 1142 s4_rsp.dest_port = 0; /* ignored */ 1143 s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ 1144 buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp)); 1145 return 1; 1146 } 1147 1148 /* try to decode a socks5 header */ 1149 #define SSH_SOCKS5_AUTHDONE 0x1000 1150 #define SSH_SOCKS5_NOAUTH 0x00 1151 #define SSH_SOCKS5_IPV4 0x01 1152 #define SSH_SOCKS5_DOMAIN 0x03 1153 #define SSH_SOCKS5_IPV6 0x04 1154 #define SSH_SOCKS5_CONNECT 0x01 1155 #define SSH_SOCKS5_SUCCESS 0x00 1156 1157 /* ARGSUSED */ 1158 static int 1159 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset) 1160 { 1161 struct { 1162 u_int8_t version; 1163 u_int8_t command; 1164 u_int8_t reserved; 1165 u_int8_t atyp; 1166 } s5_req, s5_rsp; 1167 u_int16_t dest_port; 1168 char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; 1169 u_char *p; 1170 u_int have, need, i, found, nmethods, addrlen, af; 1171 1172 debug2("channel %d: decode socks5", c->self); 1173 p = buffer_ptr(&c->input); 1174 if (p[0] != 0x05) 1175 return -1; 1176 have = buffer_len(&c->input); 1177 if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { 1178 /* format: ver | nmethods | methods */ 1179 if (have < 2) 1180 return 0; 1181 nmethods = p[1]; 1182 if (have < nmethods + 2) 1183 return 0; 1184 /* look for method: "NO AUTHENTICATION REQUIRED" */ 1185 for (found = 0, i = 2; i < nmethods + 2; i++) { 1186 if (p[i] == SSH_SOCKS5_NOAUTH) { 1187 found = 1; 1188 break; 1189 } 1190 } 1191 if (!found) { 1192 debug("channel %d: method SSH_SOCKS5_NOAUTH not found", 1193 c->self); 1194 return -1; 1195 } 1196 buffer_consume(&c->input, nmethods + 2); 1197 buffer_put_char(&c->output, 0x05); /* version */ 1198 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ 1199 FD_SET(c->sock, writeset); 1200 c->flags |= SSH_SOCKS5_AUTHDONE; 1201 debug2("channel %d: socks5 auth done", c->self); 1202 return 0; /* need more */ 1203 } 1204 debug2("channel %d: socks5 post auth", c->self); 1205 if (have < sizeof(s5_req)+1) 1206 return 0; /* need more */ 1207 memcpy(&s5_req, p, sizeof(s5_req)); 1208 if (s5_req.version != 0x05 || 1209 s5_req.command != SSH_SOCKS5_CONNECT || 1210 s5_req.reserved != 0x00) { 1211 debug2("channel %d: only socks5 connect supported", c->self); 1212 return -1; 1213 } 1214 switch (s5_req.atyp){ 1215 case SSH_SOCKS5_IPV4: 1216 addrlen = 4; 1217 af = AF_INET; 1218 break; 1219 case SSH_SOCKS5_DOMAIN: 1220 addrlen = p[sizeof(s5_req)]; 1221 af = -1; 1222 break; 1223 case SSH_SOCKS5_IPV6: 1224 addrlen = 16; 1225 af = AF_INET6; 1226 break; 1227 default: 1228 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); 1229 return -1; 1230 } 1231 need = sizeof(s5_req) + addrlen + 2; 1232 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1233 need++; 1234 if (have < need) 1235 return 0; 1236 buffer_consume(&c->input, sizeof(s5_req)); 1237 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) 1238 buffer_consume(&c->input, 1); /* host string length */ 1239 buffer_get(&c->input, &dest_addr, addrlen); 1240 buffer_get(&c->input, (char *)&dest_port, 2); 1241 dest_addr[addrlen] = '\0'; 1242 free(c->path); 1243 c->path = NULL; 1244 if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { 1245 if (addrlen >= NI_MAXHOST) { 1246 error("channel %d: dynamic request: socks5 hostname " 1247 "\"%.100s\" too long", c->self, dest_addr); 1248 return -1; 1249 } 1250 c->path = xstrdup(dest_addr); 1251 } else { 1252 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL) 1253 return -1; 1254 c->path = xstrdup(ntop); 1255 } 1256 c->host_port = ntohs(dest_port); 1257 1258 debug2("channel %d: dynamic request: socks5 host %s port %u command %u", 1259 c->self, c->path, c->host_port, s5_req.command); 1260 1261 s5_rsp.version = 0x05; 1262 s5_rsp.command = SSH_SOCKS5_SUCCESS; 1263 s5_rsp.reserved = 0; /* ignored */ 1264 s5_rsp.atyp = SSH_SOCKS5_IPV4; 1265 dest_port = 0; /* ignored */ 1266 1267 buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp)); 1268 buffer_put_int(&c->output, ntohl(INADDR_ANY)); /* bind address */ 1269 buffer_append(&c->output, &dest_port, sizeof(dest_port)); 1270 return 1; 1271 } 1272 1273 Channel * 1274 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect, 1275 int in, int out) 1276 { 1277 Channel *c; 1278 1279 debug("channel_connect_stdio_fwd %s:%d", host_to_connect, 1280 port_to_connect); 1281 1282 c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out, 1283 -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1284 0, "stdio-forward", /*nonblock*/0); 1285 1286 c->path = xstrdup(host_to_connect); 1287 c->host_port = port_to_connect; 1288 c->listening_port = 0; 1289 c->force_drain = 1; 1290 1291 channel_register_fds(c, in, out, -1, 0, 1, 0); 1292 port_open_helper(c, "direct-tcpip"); 1293 1294 return c; 1295 } 1296 1297 /* dynamic port forwarding */ 1298 static void 1299 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset) 1300 { 1301 u_char *p; 1302 u_int have; 1303 int ret; 1304 1305 have = buffer_len(&c->input); 1306 debug2("channel %d: pre_dynamic: have %d", c->self, have); 1307 /* buffer_dump(&c->input); */ 1308 /* check if the fixed size part of the packet is in buffer. */ 1309 if (have < 3) { 1310 /* need more */ 1311 FD_SET(c->sock, readset); 1312 return; 1313 } 1314 /* try to guess the protocol */ 1315 p = buffer_ptr(&c->input); 1316 switch (p[0]) { 1317 case 0x04: 1318 ret = channel_decode_socks4(c, readset, writeset); 1319 break; 1320 case 0x05: 1321 ret = channel_decode_socks5(c, readset, writeset); 1322 break; 1323 default: 1324 ret = -1; 1325 break; 1326 } 1327 if (ret < 0) { 1328 chan_mark_dead(c); 1329 } else if (ret == 0) { 1330 debug2("channel %d: pre_dynamic: need more", c->self); 1331 /* need more */ 1332 FD_SET(c->sock, readset); 1333 } else { 1334 /* switch to the next state */ 1335 c->type = SSH_CHANNEL_OPENING; 1336 port_open_helper(c, "direct-tcpip"); 1337 } 1338 } 1339 1340 /* This is our fake X11 server socket. */ 1341 /* ARGSUSED */ 1342 static void 1343 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset) 1344 { 1345 Channel *nc; 1346 struct sockaddr_storage addr; 1347 int newsock, oerrno; 1348 socklen_t addrlen; 1349 char buf[16384], *remote_ipaddr; 1350 int remote_port; 1351 1352 if (FD_ISSET(c->sock, readset)) { 1353 debug("X11 connection requested."); 1354 addrlen = sizeof(addr); 1355 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1356 if (c->single_connection) { 1357 oerrno = errno; 1358 debug2("single_connection: closing X11 listener."); 1359 channel_close_fd(&c->sock); 1360 chan_mark_dead(c); 1361 errno = oerrno; 1362 } 1363 if (newsock < 0) { 1364 if (errno != EINTR && errno != EWOULDBLOCK && 1365 errno != ECONNABORTED) 1366 error("accept: %.100s", strerror(errno)); 1367 if (errno == EMFILE || errno == ENFILE) 1368 c->notbefore = monotime() + 1; 1369 return; 1370 } 1371 set_nodelay(newsock); 1372 remote_ipaddr = get_peer_ipaddr(newsock); 1373 remote_port = get_peer_port(newsock); 1374 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 1375 remote_ipaddr, remote_port); 1376 1377 nc = channel_new("accepted x11 socket", 1378 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1379 c->local_window_max, c->local_maxpacket, 0, buf, 1); 1380 if (compat20) { 1381 packet_start(SSH2_MSG_CHANNEL_OPEN); 1382 packet_put_cstring("x11"); 1383 packet_put_int(nc->self); 1384 packet_put_int(nc->local_window_max); 1385 packet_put_int(nc->local_maxpacket); 1386 /* originator ipaddr and port */ 1387 packet_put_cstring(remote_ipaddr); 1388 if (datafellows & SSH_BUG_X11FWD) { 1389 debug2("ssh2 x11 bug compat mode"); 1390 } else { 1391 packet_put_int(remote_port); 1392 } 1393 packet_send(); 1394 } else { 1395 packet_start(SSH_SMSG_X11_OPEN); 1396 packet_put_int(nc->self); 1397 if (packet_get_protocol_flags() & 1398 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1399 packet_put_cstring(buf); 1400 packet_send(); 1401 } 1402 free(remote_ipaddr); 1403 } 1404 } 1405 1406 static void 1407 port_open_helper(Channel *c, char *rtype) 1408 { 1409 char buf[1024]; 1410 char *local_ipaddr = get_local_ipaddr(c->sock); 1411 int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); 1412 char *remote_ipaddr = get_peer_ipaddr(c->sock); 1413 int remote_port = get_peer_port(c->sock); 1414 1415 if (remote_port == -1) { 1416 /* Fake addr/port to appease peers that validate it (Tectia) */ 1417 free(remote_ipaddr); 1418 remote_ipaddr = xstrdup("127.0.0.1"); 1419 remote_port = 65535; 1420 } 1421 1422 snprintf(buf, sizeof buf, 1423 "%s: listening port %d for %.100s port %d, " 1424 "connect from %.200s port %d to %.100s port %d", 1425 rtype, c->listening_port, c->path, c->host_port, 1426 remote_ipaddr, remote_port, local_ipaddr, local_port); 1427 1428 free(c->remote_name); 1429 c->remote_name = xstrdup(buf); 1430 1431 if (compat20) { 1432 packet_start(SSH2_MSG_CHANNEL_OPEN); 1433 packet_put_cstring(rtype); 1434 packet_put_int(c->self); 1435 packet_put_int(c->local_window_max); 1436 packet_put_int(c->local_maxpacket); 1437 if (strcmp(rtype, "direct-tcpip") == 0) { 1438 /* target host, port */ 1439 packet_put_cstring(c->path); 1440 packet_put_int(c->host_port); 1441 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { 1442 /* target path */ 1443 packet_put_cstring(c->path); 1444 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1445 /* listen path */ 1446 packet_put_cstring(c->path); 1447 } else { 1448 /* listen address, port */ 1449 packet_put_cstring(c->path); 1450 packet_put_int(local_port); 1451 } 1452 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { 1453 /* reserved for future owner/mode info */ 1454 packet_put_cstring(""); 1455 } else { 1456 /* originator host and port */ 1457 packet_put_cstring(remote_ipaddr); 1458 packet_put_int((u_int)remote_port); 1459 } 1460 packet_send(); 1461 } else { 1462 packet_start(SSH_MSG_PORT_OPEN); 1463 packet_put_int(c->self); 1464 packet_put_cstring(c->path); 1465 packet_put_int(c->host_port); 1466 if (packet_get_protocol_flags() & 1467 SSH_PROTOFLAG_HOST_IN_FWD_OPEN) 1468 packet_put_cstring(c->remote_name); 1469 packet_send(); 1470 } 1471 free(remote_ipaddr); 1472 free(local_ipaddr); 1473 } 1474 1475 static void 1476 channel_set_reuseaddr(int fd) 1477 { 1478 int on = 1; 1479 1480 /* 1481 * Set socket options. 1482 * Allow local port reuse in TIME_WAIT. 1483 */ 1484 if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) 1485 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); 1486 } 1487 1488 void 1489 channel_set_x11_refuse_time(u_int refuse_time) 1490 { 1491 x11_refuse_time = refuse_time; 1492 } 1493 1494 /* 1495 * This socket is listening for connections to a forwarded TCP/IP port. 1496 */ 1497 /* ARGSUSED */ 1498 static void 1499 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset) 1500 { 1501 Channel *nc; 1502 struct sockaddr_storage addr; 1503 int newsock, nextstate; 1504 socklen_t addrlen; 1505 char *rtype; 1506 1507 if (FD_ISSET(c->sock, readset)) { 1508 debug("Connection to port %d forwarding " 1509 "to %.100s port %d requested.", 1510 c->listening_port, c->path, c->host_port); 1511 1512 if (c->type == SSH_CHANNEL_RPORT_LISTENER) { 1513 nextstate = SSH_CHANNEL_OPENING; 1514 rtype = "forwarded-tcpip"; 1515 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) { 1516 nextstate = SSH_CHANNEL_OPENING; 1517 rtype = "forwarded-streamlocal@openssh.com"; 1518 } else if (c->host_port == PORT_STREAMLOCAL) { 1519 nextstate = SSH_CHANNEL_OPENING; 1520 rtype = "direct-streamlocal@openssh.com"; 1521 } else if (c->host_port == 0) { 1522 nextstate = SSH_CHANNEL_DYNAMIC; 1523 rtype = "dynamic-tcpip"; 1524 } else { 1525 nextstate = SSH_CHANNEL_OPENING; 1526 rtype = "direct-tcpip"; 1527 } 1528 1529 addrlen = sizeof(addr); 1530 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1531 if (newsock < 0) { 1532 if (errno != EINTR && errno != EWOULDBLOCK && 1533 errno != ECONNABORTED) 1534 error("accept: %.100s", strerror(errno)); 1535 if (errno == EMFILE || errno == ENFILE) 1536 c->notbefore = monotime() + 1; 1537 return; 1538 } 1539 if (c->host_port != PORT_STREAMLOCAL) 1540 set_nodelay(newsock); 1541 nc = channel_new(rtype, nextstate, newsock, newsock, -1, 1542 c->local_window_max, c->local_maxpacket, 0, rtype, 1); 1543 nc->listening_port = c->listening_port; 1544 nc->host_port = c->host_port; 1545 if (c->path != NULL) 1546 nc->path = xstrdup(c->path); 1547 1548 if (nextstate != SSH_CHANNEL_DYNAMIC) 1549 port_open_helper(nc, rtype); 1550 } 1551 } 1552 1553 /* 1554 * This is the authentication agent socket listening for connections from 1555 * clients. 1556 */ 1557 /* ARGSUSED */ 1558 static void 1559 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset) 1560 { 1561 Channel *nc; 1562 int newsock; 1563 struct sockaddr_storage addr; 1564 socklen_t addrlen; 1565 1566 if (FD_ISSET(c->sock, readset)) { 1567 addrlen = sizeof(addr); 1568 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); 1569 if (newsock < 0) { 1570 error("accept from auth socket: %.100s", 1571 strerror(errno)); 1572 if (errno == EMFILE || errno == ENFILE) 1573 c->notbefore = monotime() + 1; 1574 return; 1575 } 1576 nc = channel_new("accepted auth socket", 1577 SSH_CHANNEL_OPENING, newsock, newsock, -1, 1578 c->local_window_max, c->local_maxpacket, 1579 0, "accepted auth socket", 1); 1580 if (compat20) { 1581 packet_start(SSH2_MSG_CHANNEL_OPEN); 1582 packet_put_cstring("auth-agent@openssh.com"); 1583 packet_put_int(nc->self); 1584 packet_put_int(c->local_window_max); 1585 packet_put_int(c->local_maxpacket); 1586 } else { 1587 packet_start(SSH_SMSG_AGENT_OPEN); 1588 packet_put_int(nc->self); 1589 } 1590 packet_send(); 1591 } 1592 } 1593 1594 /* ARGSUSED */ 1595 static void 1596 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset) 1597 { 1598 int err = 0, sock; 1599 socklen_t sz = sizeof(err); 1600 1601 if (FD_ISSET(c->sock, writeset)) { 1602 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { 1603 err = errno; 1604 error("getsockopt SO_ERROR failed"); 1605 } 1606 if (err == 0) { 1607 debug("channel %d: connected to %s port %d", 1608 c->self, c->connect_ctx.host, c->connect_ctx.port); 1609 channel_connect_ctx_free(&c->connect_ctx); 1610 c->type = SSH_CHANNEL_OPEN; 1611 if (compat20) { 1612 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1613 packet_put_int(c->remote_id); 1614 packet_put_int(c->self); 1615 packet_put_int(c->local_window); 1616 packet_put_int(c->local_maxpacket); 1617 } else { 1618 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1619 packet_put_int(c->remote_id); 1620 packet_put_int(c->self); 1621 } 1622 } else { 1623 debug("channel %d: connection failed: %s", 1624 c->self, strerror(err)); 1625 /* Try next address, if any */ 1626 if ((sock = connect_next(&c->connect_ctx)) > 0) { 1627 close(c->sock); 1628 c->sock = c->rfd = c->wfd = sock; 1629 channel_max_fd = channel_find_maxfd(); 1630 return; 1631 } 1632 /* Exhausted all addresses */ 1633 error("connect_to %.100s port %d: failed.", 1634 c->connect_ctx.host, c->connect_ctx.port); 1635 channel_connect_ctx_free(&c->connect_ctx); 1636 if (compat20) { 1637 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1638 packet_put_int(c->remote_id); 1639 packet_put_int(SSH2_OPEN_CONNECT_FAILED); 1640 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1641 packet_put_cstring(strerror(err)); 1642 packet_put_cstring(""); 1643 } 1644 } else { 1645 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1646 packet_put_int(c->remote_id); 1647 } 1648 chan_mark_dead(c); 1649 } 1650 packet_send(); 1651 } 1652 } 1653 1654 /* ARGSUSED */ 1655 static int 1656 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset) 1657 { 1658 char buf[CHAN_RBUF]; 1659 int len; 1660 1661 if (c->rfd != -1 && 1662 FD_ISSET(c->rfd, readset)) { 1663 len = read(c->rfd, buf, sizeof(buf)); 1664 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1665 return 1; 1666 if (len <= 0) { 1667 debug2("channel %d: read<=0 rfd %d len %d", 1668 c->self, c->rfd, len); 1669 if (c->type != SSH_CHANNEL_OPEN) { 1670 debug2("channel %d: not open", c->self); 1671 chan_mark_dead(c); 1672 return -1; 1673 } else if (compat13) { 1674 buffer_clear(&c->output); 1675 c->type = SSH_CHANNEL_INPUT_DRAINING; 1676 debug2("channel %d: input draining.", c->self); 1677 } else { 1678 chan_read_failed(c); 1679 } 1680 return -1; 1681 } 1682 if (c->input_filter != NULL) { 1683 if (c->input_filter(c, buf, len) == -1) { 1684 debug2("channel %d: filter stops", c->self); 1685 chan_read_failed(c); 1686 } 1687 } else if (c->datagram) { 1688 buffer_put_string(&c->input, buf, len); 1689 } else { 1690 buffer_append(&c->input, buf, len); 1691 } 1692 } 1693 return 1; 1694 } 1695 1696 /* ARGSUSED */ 1697 static int 1698 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset) 1699 { 1700 struct termios tio; 1701 u_char *data = NULL, *buf; 1702 u_int dlen, olen = 0; 1703 int len; 1704 1705 /* Send buffered output data to the socket. */ 1706 if (c->wfd != -1 && 1707 FD_ISSET(c->wfd, writeset) && 1708 buffer_len(&c->output) > 0) { 1709 olen = buffer_len(&c->output); 1710 if (c->output_filter != NULL) { 1711 if ((buf = c->output_filter(c, &data, &dlen)) == NULL) { 1712 debug2("channel %d: filter stops", c->self); 1713 if (c->type != SSH_CHANNEL_OPEN) 1714 chan_mark_dead(c); 1715 else 1716 chan_write_failed(c); 1717 return -1; 1718 } 1719 } else if (c->datagram) { 1720 buf = data = buffer_get_string(&c->output, &dlen); 1721 } else { 1722 buf = data = buffer_ptr(&c->output); 1723 dlen = buffer_len(&c->output); 1724 } 1725 1726 if (c->datagram) { 1727 /* ignore truncated writes, datagrams might get lost */ 1728 len = write(c->wfd, buf, dlen); 1729 free(data); 1730 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1731 return 1; 1732 if (len <= 0) { 1733 if (c->type != SSH_CHANNEL_OPEN) 1734 chan_mark_dead(c); 1735 else 1736 chan_write_failed(c); 1737 return -1; 1738 } 1739 goto out; 1740 } 1741 1742 len = write(c->wfd, buf, dlen); 1743 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1744 return 1; 1745 if (len <= 0) { 1746 if (c->type != SSH_CHANNEL_OPEN) { 1747 debug2("channel %d: not open", c->self); 1748 chan_mark_dead(c); 1749 return -1; 1750 } else if (compat13) { 1751 buffer_clear(&c->output); 1752 debug2("channel %d: input draining.", c->self); 1753 c->type = SSH_CHANNEL_INPUT_DRAINING; 1754 } else { 1755 chan_write_failed(c); 1756 } 1757 return -1; 1758 } 1759 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') { 1760 if (tcgetattr(c->wfd, &tio) == 0 && 1761 !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { 1762 /* 1763 * Simulate echo to reduce the impact of 1764 * traffic analysis. We need to match the 1765 * size of a SSH2_MSG_CHANNEL_DATA message 1766 * (4 byte channel id + buf) 1767 */ 1768 packet_send_ignore(4 + len); 1769 packet_send(); 1770 } 1771 } 1772 buffer_consume(&c->output, len); 1773 } 1774 out: 1775 if (compat20 && olen > 0) 1776 c->local_consumed += olen - buffer_len(&c->output); 1777 return 1; 1778 } 1779 1780 static int 1781 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset) 1782 { 1783 char buf[CHAN_RBUF]; 1784 int len; 1785 1786 /** XXX handle drain efd, too */ 1787 if (c->efd != -1) { 1788 if (c->extended_usage == CHAN_EXTENDED_WRITE && 1789 FD_ISSET(c->efd, writeset) && 1790 buffer_len(&c->extended) > 0) { 1791 len = write(c->efd, buffer_ptr(&c->extended), 1792 buffer_len(&c->extended)); 1793 debug2("channel %d: written %d to efd %d", 1794 c->self, len, c->efd); 1795 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1796 return 1; 1797 if (len <= 0) { 1798 debug2("channel %d: closing write-efd %d", 1799 c->self, c->efd); 1800 channel_close_fd(&c->efd); 1801 } else { 1802 buffer_consume(&c->extended, len); 1803 c->local_consumed += len; 1804 } 1805 } else if (c->efd != -1 && 1806 (c->extended_usage == CHAN_EXTENDED_READ || 1807 c->extended_usage == CHAN_EXTENDED_IGNORE) && 1808 FD_ISSET(c->efd, readset)) { 1809 len = read(c->efd, buf, sizeof(buf)); 1810 debug2("channel %d: read %d from efd %d", 1811 c->self, len, c->efd); 1812 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1813 return 1; 1814 if (len <= 0) { 1815 debug2("channel %d: closing read-efd %d", 1816 c->self, c->efd); 1817 channel_close_fd(&c->efd); 1818 } else { 1819 if (c->extended_usage == CHAN_EXTENDED_IGNORE) { 1820 debug3("channel %d: discard efd", 1821 c->self); 1822 } else 1823 buffer_append(&c->extended, buf, len); 1824 } 1825 } 1826 } 1827 return 1; 1828 } 1829 1830 /* ARGSUSED */ 1831 static int 1832 channel_check_window(Channel *c) 1833 { 1834 if (c->type == SSH_CHANNEL_OPEN && 1835 !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 1836 ((c->local_window_max - c->local_window > 1837 c->local_maxpacket*3) || 1838 c->local_window < c->local_window_max/2) && 1839 c->local_consumed > 0) { 1840 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 1841 packet_put_int(c->remote_id); 1842 packet_put_int(c->local_consumed); 1843 packet_send(); 1844 debug2("channel %d: window %d sent adjust %d", 1845 c->self, c->local_window, 1846 c->local_consumed); 1847 c->local_window += c->local_consumed; 1848 c->local_consumed = 0; 1849 } 1850 return 1; 1851 } 1852 1853 static void 1854 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset) 1855 { 1856 channel_handle_rfd(c, readset, writeset); 1857 channel_handle_wfd(c, readset, writeset); 1858 if (!compat20) 1859 return; 1860 channel_handle_efd(c, readset, writeset); 1861 channel_check_window(c); 1862 } 1863 1864 static u_int 1865 read_mux(Channel *c, u_int need) 1866 { 1867 char buf[CHAN_RBUF]; 1868 int len; 1869 u_int rlen; 1870 1871 if (buffer_len(&c->input) < need) { 1872 rlen = need - buffer_len(&c->input); 1873 len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); 1874 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1875 return buffer_len(&c->input); 1876 if (len <= 0) { 1877 debug2("channel %d: ctl read<=0 rfd %d len %d", 1878 c->self, c->rfd, len); 1879 chan_read_failed(c); 1880 return 0; 1881 } else 1882 buffer_append(&c->input, buf, len); 1883 } 1884 return buffer_len(&c->input); 1885 } 1886 1887 static void 1888 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset) 1889 { 1890 u_int need; 1891 ssize_t len; 1892 1893 if (!compat20) 1894 fatal("%s: entered with !compat20", __func__); 1895 1896 if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) && 1897 (c->istate == CHAN_INPUT_OPEN || 1898 c->istate == CHAN_INPUT_WAIT_DRAIN)) { 1899 /* 1900 * Don't not read past the precise end of packets to 1901 * avoid disrupting fd passing. 1902 */ 1903 if (read_mux(c, 4) < 4) /* read header */ 1904 return; 1905 need = get_u32(buffer_ptr(&c->input)); 1906 #define CHANNEL_MUX_MAX_PACKET (256 * 1024) 1907 if (need > CHANNEL_MUX_MAX_PACKET) { 1908 debug2("channel %d: packet too big %u > %u", 1909 c->self, CHANNEL_MUX_MAX_PACKET, need); 1910 chan_rcvd_oclose(c); 1911 return; 1912 } 1913 if (read_mux(c, need + 4) < need + 4) /* read body */ 1914 return; 1915 if (c->mux_rcb(c) != 0) { 1916 debug("channel %d: mux_rcb failed", c->self); 1917 chan_mark_dead(c); 1918 return; 1919 } 1920 } 1921 1922 if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) && 1923 buffer_len(&c->output) > 0) { 1924 len = write(c->wfd, buffer_ptr(&c->output), 1925 buffer_len(&c->output)); 1926 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 1927 return; 1928 if (len <= 0) { 1929 chan_mark_dead(c); 1930 return; 1931 } 1932 buffer_consume(&c->output, len); 1933 } 1934 } 1935 1936 static void 1937 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset) 1938 { 1939 Channel *nc; 1940 struct sockaddr_storage addr; 1941 socklen_t addrlen; 1942 int newsock; 1943 uid_t euid; 1944 gid_t egid; 1945 1946 if (!FD_ISSET(c->sock, readset)) 1947 return; 1948 1949 debug("multiplexing control connection"); 1950 1951 /* 1952 * Accept connection on control socket 1953 */ 1954 memset(&addr, 0, sizeof(addr)); 1955 addrlen = sizeof(addr); 1956 if ((newsock = accept(c->sock, (struct sockaddr*)&addr, 1957 &addrlen)) == -1) { 1958 error("%s accept: %s", __func__, strerror(errno)); 1959 if (errno == EMFILE || errno == ENFILE) 1960 c->notbefore = monotime() + 1; 1961 return; 1962 } 1963 1964 if (getpeereid(newsock, &euid, &egid) < 0) { 1965 error("%s getpeereid failed: %s", __func__, 1966 strerror(errno)); 1967 close(newsock); 1968 return; 1969 } 1970 if ((euid != 0) && (getuid() != euid)) { 1971 error("multiplex uid mismatch: peer euid %u != uid %u", 1972 (u_int)euid, (u_int)getuid()); 1973 close(newsock); 1974 return; 1975 } 1976 nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT, 1977 newsock, newsock, -1, c->local_window_max, 1978 c->local_maxpacket, 0, "mux-control", 1); 1979 nc->mux_rcb = c->mux_rcb; 1980 debug3("%s: new mux channel %d fd %d", __func__, 1981 nc->self, nc->sock); 1982 /* establish state */ 1983 nc->mux_rcb(nc); 1984 /* mux state transitions must not elicit protocol messages */ 1985 nc->flags |= CHAN_LOCAL; 1986 } 1987 1988 /* ARGSUSED */ 1989 static void 1990 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset) 1991 { 1992 int len; 1993 1994 /* Send buffered output data to the socket. */ 1995 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { 1996 len = write(c->sock, buffer_ptr(&c->output), 1997 buffer_len(&c->output)); 1998 if (len <= 0) 1999 buffer_clear(&c->output); 2000 else 2001 buffer_consume(&c->output, len); 2002 } 2003 } 2004 2005 static void 2006 channel_handler_init_20(void) 2007 { 2008 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2009 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2010 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2011 channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; 2012 channel_pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; 2013 channel_pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; 2014 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2015 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2016 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2017 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2018 channel_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; 2019 channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; 2020 2021 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2022 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2023 channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; 2024 channel_post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; 2025 channel_post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; 2026 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2027 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2028 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2029 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2030 channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; 2031 channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; 2032 } 2033 2034 static void 2035 channel_handler_init_13(void) 2036 { 2037 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; 2038 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; 2039 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2040 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2041 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2042 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; 2043 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; 2044 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2045 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2046 2047 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2048 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2049 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2050 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2051 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; 2052 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2053 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2054 } 2055 2056 static void 2057 channel_handler_init_15(void) 2058 { 2059 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; 2060 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 2061 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 2062 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 2063 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 2064 channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; 2065 channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; 2066 2067 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 2068 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 2069 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 2070 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; 2071 channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; 2072 channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; 2073 } 2074 2075 static void 2076 channel_handler_init(void) 2077 { 2078 int i; 2079 2080 for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { 2081 channel_pre[i] = NULL; 2082 channel_post[i] = NULL; 2083 } 2084 if (compat20) 2085 channel_handler_init_20(); 2086 else if (compat13) 2087 channel_handler_init_13(); 2088 else 2089 channel_handler_init_15(); 2090 } 2091 2092 /* gc dead channels */ 2093 static void 2094 channel_garbage_collect(Channel *c) 2095 { 2096 if (c == NULL) 2097 return; 2098 if (c->detach_user != NULL) { 2099 if (!chan_is_dead(c, c->detach_close)) 2100 return; 2101 debug2("channel %d: gc: notify user", c->self); 2102 c->detach_user(c->self, NULL); 2103 /* if we still have a callback */ 2104 if (c->detach_user != NULL) 2105 return; 2106 debug2("channel %d: gc: user detached", c->self); 2107 } 2108 if (!chan_is_dead(c, 1)) 2109 return; 2110 debug2("channel %d: garbage collecting", c->self); 2111 channel_free(c); 2112 } 2113 2114 static void 2115 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset, 2116 time_t *unpause_secs) 2117 { 2118 static int did_init = 0; 2119 u_int i, oalloc; 2120 Channel *c; 2121 time_t now; 2122 2123 if (!did_init) { 2124 channel_handler_init(); 2125 did_init = 1; 2126 } 2127 now = monotime(); 2128 if (unpause_secs != NULL) 2129 *unpause_secs = 0; 2130 for (i = 0, oalloc = channels_alloc; i < oalloc; i++) { 2131 c = channels[i]; 2132 if (c == NULL) 2133 continue; 2134 if (c->delayed) { 2135 if (ftab == channel_pre) 2136 c->delayed = 0; 2137 else 2138 continue; 2139 } 2140 if (ftab[c->type] != NULL) { 2141 /* 2142 * Run handlers that are not paused. 2143 */ 2144 if (c->notbefore <= now) 2145 (*ftab[c->type])(c, readset, writeset); 2146 else if (unpause_secs != NULL) { 2147 /* 2148 * Collect the time that the earliest 2149 * channel comes off pause. 2150 */ 2151 debug3("%s: chan %d: skip for %d more seconds", 2152 __func__, c->self, 2153 (int)(c->notbefore - now)); 2154 if (*unpause_secs == 0 || 2155 (c->notbefore - now) < *unpause_secs) 2156 *unpause_secs = c->notbefore - now; 2157 } 2158 } 2159 channel_garbage_collect(c); 2160 } 2161 if (unpause_secs != NULL && *unpause_secs != 0) 2162 debug3("%s: first channel unpauses in %d seconds", 2163 __func__, (int)*unpause_secs); 2164 } 2165 2166 /* 2167 * Allocate/update select bitmasks and add any bits relevant to channels in 2168 * select bitmasks. 2169 */ 2170 void 2171 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, 2172 u_int *nallocp, time_t *minwait_secs, int rekeying) 2173 { 2174 u_int n, sz, nfdset; 2175 2176 n = MAXIMUM(*maxfdp, channel_max_fd); 2177 2178 nfdset = howmany(n+1, NFDBITS); 2179 /* Explicitly test here, because xrealloc isn't always called */ 2180 if (nfdset && SIZE_MAX / nfdset < sizeof(fd_mask)) 2181 fatal("channel_prepare_select: max_fd (%d) is too large", n); 2182 sz = nfdset * sizeof(fd_mask); 2183 2184 /* perhaps check sz < nalloc/2 and shrink? */ 2185 if (*readsetp == NULL || sz > *nallocp) { 2186 *readsetp = xreallocarray(*readsetp, nfdset, sizeof(fd_mask)); 2187 *writesetp = xreallocarray(*writesetp, nfdset, sizeof(fd_mask)); 2188 *nallocp = sz; 2189 } 2190 *maxfdp = n; 2191 memset(*readsetp, 0, sz); 2192 memset(*writesetp, 0, sz); 2193 2194 if (!rekeying) 2195 channel_handler(channel_pre, *readsetp, *writesetp, 2196 minwait_secs); 2197 } 2198 2199 /* 2200 * After select, perform any appropriate operations for channels which have 2201 * events pending. 2202 */ 2203 void 2204 channel_after_select(fd_set *readset, fd_set *writeset) 2205 { 2206 channel_handler(channel_post, readset, writeset, NULL); 2207 } 2208 2209 2210 /* If there is data to send to the connection, enqueue some of it now. */ 2211 void 2212 channel_output_poll(void) 2213 { 2214 Channel *c; 2215 u_int i, len; 2216 2217 for (i = 0; i < channels_alloc; i++) { 2218 c = channels[i]; 2219 if (c == NULL) 2220 continue; 2221 2222 /* 2223 * We are only interested in channels that can have buffered 2224 * incoming data. 2225 */ 2226 if (compat13) { 2227 if (c->type != SSH_CHANNEL_OPEN && 2228 c->type != SSH_CHANNEL_INPUT_DRAINING) 2229 continue; 2230 } else { 2231 if (c->type != SSH_CHANNEL_OPEN) 2232 continue; 2233 } 2234 if (compat20 && 2235 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 2236 /* XXX is this true? */ 2237 debug3("channel %d: will not send data after close", c->self); 2238 continue; 2239 } 2240 2241 /* Get the amount of buffered data for this channel. */ 2242 if ((c->istate == CHAN_INPUT_OPEN || 2243 c->istate == CHAN_INPUT_WAIT_DRAIN) && 2244 (len = buffer_len(&c->input)) > 0) { 2245 if (c->datagram) { 2246 if (len > 0) { 2247 u_char *data; 2248 u_int dlen; 2249 2250 data = buffer_get_string(&c->input, 2251 &dlen); 2252 if (dlen > c->remote_window || 2253 dlen > c->remote_maxpacket) { 2254 debug("channel %d: datagram " 2255 "too big for channel", 2256 c->self); 2257 free(data); 2258 continue; 2259 } 2260 packet_start(SSH2_MSG_CHANNEL_DATA); 2261 packet_put_int(c->remote_id); 2262 packet_put_string(data, dlen); 2263 packet_send(); 2264 c->remote_window -= dlen; 2265 free(data); 2266 } 2267 continue; 2268 } 2269 /* 2270 * Send some data for the other side over the secure 2271 * connection. 2272 */ 2273 if (compat20) { 2274 if (len > c->remote_window) 2275 len = c->remote_window; 2276 if (len > c->remote_maxpacket) 2277 len = c->remote_maxpacket; 2278 } else { 2279 if (packet_is_interactive()) { 2280 if (len > 1024) 2281 len = 512; 2282 } else { 2283 /* Keep the packets at reasonable size. */ 2284 if (len > packet_get_maxsize()/2) 2285 len = packet_get_maxsize()/2; 2286 } 2287 } 2288 if (len > 0) { 2289 packet_start(compat20 ? 2290 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); 2291 packet_put_int(c->remote_id); 2292 packet_put_string(buffer_ptr(&c->input), len); 2293 packet_send(); 2294 buffer_consume(&c->input, len); 2295 c->remote_window -= len; 2296 } 2297 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 2298 if (compat13) 2299 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); 2300 /* 2301 * input-buffer is empty and read-socket shutdown: 2302 * tell peer, that we will not send more data: send IEOF. 2303 * hack for extended data: delay EOF if EFD still in use. 2304 */ 2305 if (CHANNEL_EFD_INPUT_ACTIVE(c)) 2306 debug2("channel %d: ibuf_empty delayed efd %d/(%d)", 2307 c->self, c->efd, buffer_len(&c->extended)); 2308 else 2309 chan_ibuf_empty(c); 2310 } 2311 /* Send extended data, i.e. stderr */ 2312 if (compat20 && 2313 !(c->flags & CHAN_EOF_SENT) && 2314 c->remote_window > 0 && 2315 (len = buffer_len(&c->extended)) > 0 && 2316 c->extended_usage == CHAN_EXTENDED_READ) { 2317 debug2("channel %d: rwin %u elen %u euse %d", 2318 c->self, c->remote_window, buffer_len(&c->extended), 2319 c->extended_usage); 2320 if (len > c->remote_window) 2321 len = c->remote_window; 2322 if (len > c->remote_maxpacket) 2323 len = c->remote_maxpacket; 2324 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); 2325 packet_put_int(c->remote_id); 2326 packet_put_int(SSH2_EXTENDED_DATA_STDERR); 2327 packet_put_string(buffer_ptr(&c->extended), len); 2328 packet_send(); 2329 buffer_consume(&c->extended, len); 2330 c->remote_window -= len; 2331 debug2("channel %d: sent ext data %d", c->self, len); 2332 } 2333 } 2334 } 2335 2336 2337 /* -- protocol input */ 2338 2339 /* ARGSUSED */ 2340 int 2341 channel_input_data(int type, u_int32_t seq, void *ctxt) 2342 { 2343 int id; 2344 const u_char *data; 2345 u_int data_len, win_len; 2346 Channel *c; 2347 2348 /* Get the channel number and verify it. */ 2349 id = packet_get_int(); 2350 c = channel_lookup(id); 2351 if (c == NULL) 2352 packet_disconnect("Received data for nonexistent channel %d.", id); 2353 2354 /* Ignore any data for non-open channels (might happen on close) */ 2355 if (c->type != SSH_CHANNEL_OPEN && 2356 c->type != SSH_CHANNEL_X11_OPEN) 2357 return 0; 2358 2359 /* Get the data. */ 2360 data = packet_get_string_ptr(&data_len); 2361 win_len = data_len; 2362 if (c->datagram) 2363 win_len += 4; /* string length header */ 2364 2365 /* 2366 * Ignore data for protocol > 1.3 if output end is no longer open. 2367 * For protocol 2 the sending side is reducing its window as it sends 2368 * data, so we must 'fake' consumption of the data in order to ensure 2369 * that window updates are sent back. Otherwise the connection might 2370 * deadlock. 2371 */ 2372 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { 2373 if (compat20) { 2374 c->local_window -= win_len; 2375 c->local_consumed += win_len; 2376 } 2377 return 0; 2378 } 2379 2380 if (compat20) { 2381 if (win_len > c->local_maxpacket) { 2382 logit("channel %d: rcvd big packet %d, maxpack %d", 2383 c->self, win_len, c->local_maxpacket); 2384 } 2385 if (win_len > c->local_window) { 2386 logit("channel %d: rcvd too much data %d, win %d", 2387 c->self, win_len, c->local_window); 2388 return 0; 2389 } 2390 c->local_window -= win_len; 2391 } 2392 if (c->datagram) 2393 buffer_put_string(&c->output, data, data_len); 2394 else 2395 buffer_append(&c->output, data, data_len); 2396 packet_check_eom(); 2397 return 0; 2398 } 2399 2400 /* ARGSUSED */ 2401 int 2402 channel_input_extended_data(int type, u_int32_t seq, void *ctxt) 2403 { 2404 int id; 2405 char *data; 2406 u_int data_len, tcode; 2407 Channel *c; 2408 2409 /* Get the channel number and verify it. */ 2410 id = packet_get_int(); 2411 c = channel_lookup(id); 2412 2413 if (c == NULL) 2414 packet_disconnect("Received extended_data for bad channel %d.", id); 2415 if (c->type != SSH_CHANNEL_OPEN) { 2416 logit("channel %d: ext data for non open", id); 2417 return 0; 2418 } 2419 if (c->flags & CHAN_EOF_RCVD) { 2420 if (datafellows & SSH_BUG_EXTEOF) 2421 debug("channel %d: accepting ext data after eof", id); 2422 else 2423 packet_disconnect("Received extended_data after EOF " 2424 "on channel %d.", id); 2425 } 2426 tcode = packet_get_int(); 2427 if (c->efd == -1 || 2428 c->extended_usage != CHAN_EXTENDED_WRITE || 2429 tcode != SSH2_EXTENDED_DATA_STDERR) { 2430 logit("channel %d: bad ext data", c->self); 2431 return 0; 2432 } 2433 data = packet_get_string(&data_len); 2434 packet_check_eom(); 2435 if (data_len > c->local_window) { 2436 logit("channel %d: rcvd too much extended_data %d, win %d", 2437 c->self, data_len, c->local_window); 2438 free(data); 2439 return 0; 2440 } 2441 debug2("channel %d: rcvd ext data %d", c->self, data_len); 2442 c->local_window -= data_len; 2443 buffer_append(&c->extended, data, data_len); 2444 free(data); 2445 return 0; 2446 } 2447 2448 /* ARGSUSED */ 2449 int 2450 channel_input_ieof(int type, u_int32_t seq, void *ctxt) 2451 { 2452 int id; 2453 Channel *c; 2454 2455 id = packet_get_int(); 2456 packet_check_eom(); 2457 c = channel_lookup(id); 2458 if (c == NULL) 2459 packet_disconnect("Received ieof for nonexistent channel %d.", id); 2460 chan_rcvd_ieof(c); 2461 2462 /* XXX force input close */ 2463 if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { 2464 debug("channel %d: FORCE input drain", c->self); 2465 c->istate = CHAN_INPUT_WAIT_DRAIN; 2466 if (buffer_len(&c->input) == 0) 2467 chan_ibuf_empty(c); 2468 } 2469 return 0; 2470 } 2471 2472 /* ARGSUSED */ 2473 int 2474 channel_input_close(int type, u_int32_t seq, void *ctxt) 2475 { 2476 int id; 2477 Channel *c; 2478 2479 id = packet_get_int(); 2480 packet_check_eom(); 2481 c = channel_lookup(id); 2482 if (c == NULL) 2483 packet_disconnect("Received close for nonexistent channel %d.", id); 2484 2485 /* 2486 * Send a confirmation that we have closed the channel and no more 2487 * data is coming for it. 2488 */ 2489 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); 2490 packet_put_int(c->remote_id); 2491 packet_send(); 2492 2493 /* 2494 * If the channel is in closed state, we have sent a close request, 2495 * and the other side will eventually respond with a confirmation. 2496 * Thus, we cannot free the channel here, because then there would be 2497 * no-one to receive the confirmation. The channel gets freed when 2498 * the confirmation arrives. 2499 */ 2500 if (c->type != SSH_CHANNEL_CLOSED) { 2501 /* 2502 * Not a closed channel - mark it as draining, which will 2503 * cause it to be freed later. 2504 */ 2505 buffer_clear(&c->input); 2506 c->type = SSH_CHANNEL_OUTPUT_DRAINING; 2507 } 2508 return 0; 2509 } 2510 2511 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ 2512 /* ARGSUSED */ 2513 int 2514 channel_input_oclose(int type, u_int32_t seq, void *ctxt) 2515 { 2516 int id = packet_get_int(); 2517 Channel *c = channel_lookup(id); 2518 2519 packet_check_eom(); 2520 if (c == NULL) 2521 packet_disconnect("Received oclose for nonexistent channel %d.", id); 2522 chan_rcvd_oclose(c); 2523 return 0; 2524 } 2525 2526 /* ARGSUSED */ 2527 int 2528 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) 2529 { 2530 int id = packet_get_int(); 2531 Channel *c = channel_lookup(id); 2532 2533 packet_check_eom(); 2534 if (c == NULL) 2535 packet_disconnect("Received close confirmation for " 2536 "out-of-range channel %d.", id); 2537 if (c->type != SSH_CHANNEL_CLOSED && c->type != SSH_CHANNEL_ABANDONED) 2538 packet_disconnect("Received close confirmation for " 2539 "non-closed channel %d (type %d).", id, c->type); 2540 channel_free(c); 2541 return 0; 2542 } 2543 2544 /* ARGSUSED */ 2545 int 2546 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) 2547 { 2548 int id, remote_id; 2549 Channel *c; 2550 2551 id = packet_get_int(); 2552 c = channel_lookup(id); 2553 2554 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2555 packet_disconnect("Received open confirmation for " 2556 "non-opening channel %d.", id); 2557 remote_id = packet_get_int(); 2558 /* Record the remote channel number and mark that the channel is now open. */ 2559 c->remote_id = remote_id; 2560 c->type = SSH_CHANNEL_OPEN; 2561 2562 if (compat20) { 2563 c->remote_window = packet_get_int(); 2564 c->remote_maxpacket = packet_get_int(); 2565 if (c->open_confirm) { 2566 debug2("callback start"); 2567 c->open_confirm(c->self, 1, c->open_confirm_ctx); 2568 debug2("callback done"); 2569 } 2570 debug2("channel %d: open confirm rwindow %u rmax %u", c->self, 2571 c->remote_window, c->remote_maxpacket); 2572 } 2573 packet_check_eom(); 2574 return 0; 2575 } 2576 2577 static char * 2578 reason2txt(int reason) 2579 { 2580 switch (reason) { 2581 case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: 2582 return "administratively prohibited"; 2583 case SSH2_OPEN_CONNECT_FAILED: 2584 return "connect failed"; 2585 case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: 2586 return "unknown channel type"; 2587 case SSH2_OPEN_RESOURCE_SHORTAGE: 2588 return "resource shortage"; 2589 } 2590 return "unknown reason"; 2591 } 2592 2593 /* ARGSUSED */ 2594 int 2595 channel_input_open_failure(int type, u_int32_t seq, void *ctxt) 2596 { 2597 int id, reason; 2598 char *msg = NULL, *lang = NULL; 2599 Channel *c; 2600 2601 id = packet_get_int(); 2602 c = channel_lookup(id); 2603 2604 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 2605 packet_disconnect("Received open failure for " 2606 "non-opening channel %d.", id); 2607 if (compat20) { 2608 reason = packet_get_int(); 2609 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 2610 msg = packet_get_string(NULL); 2611 lang = packet_get_string(NULL); 2612 } 2613 logit("channel %d: open failed: %s%s%s", id, 2614 reason2txt(reason), msg ? ": ": "", msg ? msg : ""); 2615 free(msg); 2616 free(lang); 2617 if (c->open_confirm) { 2618 debug2("callback start"); 2619 c->open_confirm(c->self, 0, c->open_confirm_ctx); 2620 debug2("callback done"); 2621 } 2622 } 2623 packet_check_eom(); 2624 /* Schedule the channel for cleanup/deletion. */ 2625 chan_mark_dead(c); 2626 return 0; 2627 } 2628 2629 /* ARGSUSED */ 2630 int 2631 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) 2632 { 2633 Channel *c; 2634 int id; 2635 u_int adjust, tmp; 2636 2637 if (!compat20) 2638 return 0; 2639 2640 /* Get the channel number and verify it. */ 2641 id = packet_get_int(); 2642 c = channel_lookup(id); 2643 2644 if (c == NULL) { 2645 logit("Received window adjust for non-open channel %d.", id); 2646 return 0; 2647 } 2648 adjust = packet_get_int(); 2649 packet_check_eom(); 2650 debug2("channel %d: rcvd adjust %u", id, adjust); 2651 if ((tmp = c->remote_window + adjust) < c->remote_window) 2652 fatal("channel %d: adjust %u overflows remote window %u", 2653 id, adjust, c->remote_window); 2654 c->remote_window = tmp; 2655 return 0; 2656 } 2657 2658 /* ARGSUSED */ 2659 int 2660 channel_input_port_open(int type, u_int32_t seq, void *ctxt) 2661 { 2662 Channel *c = NULL; 2663 u_short host_port; 2664 char *host, *originator_string; 2665 int remote_id; 2666 2667 remote_id = packet_get_int(); 2668 host = packet_get_string(NULL); 2669 host_port = packet_get_int(); 2670 2671 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 2672 originator_string = packet_get_string(NULL); 2673 } else { 2674 originator_string = xstrdup("unknown (remote did not supply name)"); 2675 } 2676 packet_check_eom(); 2677 c = channel_connect_to_port(host, host_port, 2678 "connected socket", originator_string); 2679 free(originator_string); 2680 free(host); 2681 if (c == NULL) { 2682 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 2683 packet_put_int(remote_id); 2684 packet_send(); 2685 } else 2686 c->remote_id = remote_id; 2687 return 0; 2688 } 2689 2690 /* ARGSUSED */ 2691 int 2692 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt) 2693 { 2694 Channel *c; 2695 struct channel_confirm *cc; 2696 int id; 2697 2698 /* Reset keepalive timeout */ 2699 packet_set_alive_timeouts(0); 2700 2701 id = packet_get_int(); 2702 packet_check_eom(); 2703 2704 debug2("channel_input_status_confirm: type %d id %d", type, id); 2705 2706 if ((c = channel_lookup(id)) == NULL) { 2707 logit("channel_input_status_confirm: %d: unknown", id); 2708 return 0; 2709 } 2710 if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) 2711 return 0; 2712 cc->cb(type, c, cc->ctx); 2713 TAILQ_REMOVE(&c->status_confirms, cc, entry); 2714 explicit_bzero(cc, sizeof(*cc)); 2715 free(cc); 2716 return 0; 2717 } 2718 2719 /* -- tcp forwarding */ 2720 2721 void 2722 channel_set_af(int af) 2723 { 2724 IPv4or6 = af; 2725 } 2726 2727 2728 /* 2729 * Determine whether or not a port forward listens to loopback, the 2730 * specified address or wildcard. On the client, a specified bind 2731 * address will always override gateway_ports. On the server, a 2732 * gateway_ports of 1 (``yes'') will override the client's specification 2733 * and force a wildcard bind, whereas a value of 2 (``clientspecified'') 2734 * will bind to whatever address the client asked for. 2735 * 2736 * Special-case listen_addrs are: 2737 * 2738 * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR 2739 * "" (empty string), "*" -> wildcard v4/v6 2740 * "localhost" -> loopback v4/v6 2741 * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set 2742 */ 2743 static const char * 2744 channel_fwd_bind_addr(const char *listen_addr, int *wildcardp, 2745 int is_client, struct ForwardOptions *fwd_opts) 2746 { 2747 const char *addr = NULL; 2748 int wildcard = 0; 2749 2750 if (listen_addr == NULL) { 2751 /* No address specified: default to gateway_ports setting */ 2752 if (fwd_opts->gateway_ports) 2753 wildcard = 1; 2754 } else if (fwd_opts->gateway_ports || is_client) { 2755 if (((datafellows & SSH_OLD_FORWARD_ADDR) && 2756 strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || 2757 *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || 2758 (!is_client && fwd_opts->gateway_ports == 1)) { 2759 wildcard = 1; 2760 /* 2761 * Notify client if they requested a specific listen 2762 * address and it was overridden. 2763 */ 2764 if (*listen_addr != '\0' && 2765 strcmp(listen_addr, "0.0.0.0") != 0 && 2766 strcmp(listen_addr, "*") != 0) { 2767 packet_send_debug("Forwarding listen address " 2768 "\"%s\" overridden by server " 2769 "GatewayPorts", listen_addr); 2770 } 2771 } else if (strcmp(listen_addr, "localhost") != 0 || 2772 strcmp(listen_addr, "127.0.0.1") == 0 || 2773 strcmp(listen_addr, "::1") == 0) { 2774 /* Accept localhost address when GatewayPorts=yes */ 2775 addr = listen_addr; 2776 } 2777 } else if (strcmp(listen_addr, "127.0.0.1") == 0 || 2778 strcmp(listen_addr, "::1") == 0) { 2779 /* 2780 * If a specific IPv4/IPv6 localhost address has been 2781 * requested then accept it even if gateway_ports is in 2782 * effect. This allows the client to prefer IPv4 or IPv6. 2783 */ 2784 addr = listen_addr; 2785 } 2786 if (wildcardp != NULL) 2787 *wildcardp = wildcard; 2788 return addr; 2789 } 2790 2791 static int 2792 channel_setup_fwd_listener_tcpip(int type, struct Forward *fwd, 2793 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 2794 { 2795 Channel *c; 2796 int sock, r, success = 0, wildcard = 0, is_client; 2797 struct addrinfo hints, *ai, *aitop; 2798 const char *host, *addr; 2799 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 2800 in_port_t *lport_p; 2801 2802 is_client = (type == SSH_CHANNEL_PORT_LISTENER); 2803 2804 if (is_client && fwd->connect_path != NULL) { 2805 host = fwd->connect_path; 2806 } else { 2807 host = (type == SSH_CHANNEL_RPORT_LISTENER) ? 2808 fwd->listen_host : fwd->connect_host; 2809 if (host == NULL) { 2810 error("No forward host name."); 2811 return 0; 2812 } 2813 if (strlen(host) >= NI_MAXHOST) { 2814 error("Forward host name too long."); 2815 return 0; 2816 } 2817 } 2818 2819 /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ 2820 addr = channel_fwd_bind_addr(fwd->listen_host, &wildcard, 2821 is_client, fwd_opts); 2822 debug3("%s: type %d wildcard %d addr %s", __func__, 2823 type, wildcard, (addr == NULL) ? "NULL" : addr); 2824 2825 /* 2826 * getaddrinfo returns a loopback address if the hostname is 2827 * set to NULL and hints.ai_flags is not AI_PASSIVE 2828 */ 2829 memset(&hints, 0, sizeof(hints)); 2830 hints.ai_family = IPv4or6; 2831 hints.ai_flags = wildcard ? AI_PASSIVE : 0; 2832 hints.ai_socktype = SOCK_STREAM; 2833 snprintf(strport, sizeof strport, "%d", fwd->listen_port); 2834 if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { 2835 if (addr == NULL) { 2836 /* This really shouldn't happen */ 2837 packet_disconnect("getaddrinfo: fatal error: %s", 2838 ssh_gai_strerror(r)); 2839 } else { 2840 error("%s: getaddrinfo(%.64s): %s", __func__, addr, 2841 ssh_gai_strerror(r)); 2842 } 2843 return 0; 2844 } 2845 if (allocated_listen_port != NULL) 2846 *allocated_listen_port = 0; 2847 for (ai = aitop; ai; ai = ai->ai_next) { 2848 switch (ai->ai_family) { 2849 case AF_INET: 2850 lport_p = &((struct sockaddr_in *)ai->ai_addr)-> 2851 sin_port; 2852 break; 2853 case AF_INET6: 2854 lport_p = &((struct sockaddr_in6 *)ai->ai_addr)-> 2855 sin6_port; 2856 break; 2857 default: 2858 continue; 2859 } 2860 /* 2861 * If allocating a port for -R forwards, then use the 2862 * same port for all address families. 2863 */ 2864 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 && 2865 allocated_listen_port != NULL && *allocated_listen_port > 0) 2866 *lport_p = htons(*allocated_listen_port); 2867 2868 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 2869 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 2870 error("%s: getnameinfo failed", __func__); 2871 continue; 2872 } 2873 /* Create a port to listen for the host. */ 2874 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 2875 if (sock < 0) { 2876 /* this is no error since kernel may not support ipv6 */ 2877 verbose("socket: %.100s", strerror(errno)); 2878 continue; 2879 } 2880 2881 channel_set_reuseaddr(sock); 2882 2883 debug("Local forwarding listening on %s port %s.", 2884 ntop, strport); 2885 2886 /* Bind the socket to the address. */ 2887 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 2888 /* address can be in use ipv6 address is already bound */ 2889 verbose("bind: %.100s", strerror(errno)); 2890 close(sock); 2891 continue; 2892 } 2893 /* Start listening for connections on the socket. */ 2894 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 2895 error("listen: %.100s", strerror(errno)); 2896 close(sock); 2897 continue; 2898 } 2899 2900 /* 2901 * fwd->listen_port == 0 requests a dynamically allocated port - 2902 * record what we got. 2903 */ 2904 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 && 2905 allocated_listen_port != NULL && 2906 *allocated_listen_port == 0) { 2907 *allocated_listen_port = get_local_port(sock); 2908 debug("Allocated listen port %d", 2909 *allocated_listen_port); 2910 } 2911 2912 /* Allocate a channel number for the socket. */ 2913 c = channel_new("port listener", type, sock, sock, -1, 2914 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 2915 0, "port listener", 1); 2916 c->path = xstrdup(host); 2917 c->host_port = fwd->connect_port; 2918 c->listening_addr = addr == NULL ? NULL : xstrdup(addr); 2919 if (fwd->listen_port == 0 && allocated_listen_port != NULL && 2920 !(datafellows & SSH_BUG_DYNAMIC_RPORT)) 2921 c->listening_port = *allocated_listen_port; 2922 else 2923 c->listening_port = fwd->listen_port; 2924 success = 1; 2925 } 2926 if (success == 0) 2927 error("%s: cannot listen to port: %d", __func__, 2928 fwd->listen_port); 2929 freeaddrinfo(aitop); 2930 return success; 2931 } 2932 2933 static int 2934 channel_setup_fwd_listener_streamlocal(int type, struct Forward *fwd, 2935 struct ForwardOptions *fwd_opts) 2936 { 2937 struct sockaddr_un sunaddr; 2938 const char *path; 2939 Channel *c; 2940 int port, sock; 2941 mode_t omask; 2942 2943 switch (type) { 2944 case SSH_CHANNEL_UNIX_LISTENER: 2945 if (fwd->connect_path != NULL) { 2946 if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { 2947 error("Local connecting path too long: %s", 2948 fwd->connect_path); 2949 return 0; 2950 } 2951 path = fwd->connect_path; 2952 port = PORT_STREAMLOCAL; 2953 } else { 2954 if (fwd->connect_host == NULL) { 2955 error("No forward host name."); 2956 return 0; 2957 } 2958 if (strlen(fwd->connect_host) >= NI_MAXHOST) { 2959 error("Forward host name too long."); 2960 return 0; 2961 } 2962 path = fwd->connect_host; 2963 port = fwd->connect_port; 2964 } 2965 break; 2966 case SSH_CHANNEL_RUNIX_LISTENER: 2967 path = fwd->listen_path; 2968 port = PORT_STREAMLOCAL; 2969 break; 2970 default: 2971 error("%s: unexpected channel type %d", __func__, type); 2972 return 0; 2973 } 2974 2975 if (fwd->listen_path == NULL) { 2976 error("No forward path name."); 2977 return 0; 2978 } 2979 if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { 2980 error("Local listening path too long: %s", fwd->listen_path); 2981 return 0; 2982 } 2983 2984 debug3("%s: type %d path %s", __func__, type, fwd->listen_path); 2985 2986 /* Start a Unix domain listener. */ 2987 omask = umask(fwd_opts->streamlocal_bind_mask); 2988 sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, 2989 fwd_opts->streamlocal_bind_unlink); 2990 umask(omask); 2991 if (sock < 0) 2992 return 0; 2993 2994 debug("Local forwarding listening on path %s.", fwd->listen_path); 2995 2996 /* Allocate a channel number for the socket. */ 2997 c = channel_new("unix listener", type, sock, sock, -1, 2998 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 2999 0, "unix listener", 1); 3000 c->path = xstrdup(path); 3001 c->host_port = port; 3002 c->listening_port = PORT_STREAMLOCAL; 3003 c->listening_addr = xstrdup(fwd->listen_path); 3004 return 1; 3005 } 3006 3007 static int 3008 channel_cancel_rport_listener_tcpip(const char *host, u_short port) 3009 { 3010 u_int i; 3011 int found = 0; 3012 3013 for (i = 0; i < channels_alloc; i++) { 3014 Channel *c = channels[i]; 3015 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) 3016 continue; 3017 if (strcmp(c->path, host) == 0 && c->listening_port == port) { 3018 debug2("%s: close channel %d", __func__, i); 3019 channel_free(c); 3020 found = 1; 3021 } 3022 } 3023 3024 return (found); 3025 } 3026 3027 static int 3028 channel_cancel_rport_listener_streamlocal(const char *path) 3029 { 3030 u_int i; 3031 int found = 0; 3032 3033 for (i = 0; i < channels_alloc; i++) { 3034 Channel *c = channels[i]; 3035 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) 3036 continue; 3037 if (c->path == NULL) 3038 continue; 3039 if (strcmp(c->path, path) == 0) { 3040 debug2("%s: close channel %d", __func__, i); 3041 channel_free(c); 3042 found = 1; 3043 } 3044 } 3045 3046 return (found); 3047 } 3048 3049 int 3050 channel_cancel_rport_listener(struct Forward *fwd) 3051 { 3052 if (fwd->listen_path != NULL) 3053 return channel_cancel_rport_listener_streamlocal(fwd->listen_path); 3054 else 3055 return channel_cancel_rport_listener_tcpip(fwd->listen_host, fwd->listen_port); 3056 } 3057 3058 static int 3059 channel_cancel_lport_listener_tcpip(const char *lhost, u_short lport, 3060 int cport, struct ForwardOptions *fwd_opts) 3061 { 3062 u_int i; 3063 int found = 0; 3064 const char *addr = channel_fwd_bind_addr(lhost, NULL, 1, fwd_opts); 3065 3066 for (i = 0; i < channels_alloc; i++) { 3067 Channel *c = channels[i]; 3068 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) 3069 continue; 3070 if (c->listening_port != lport) 3071 continue; 3072 if (cport == CHANNEL_CANCEL_PORT_STATIC) { 3073 /* skip dynamic forwardings */ 3074 if (c->host_port == 0) 3075 continue; 3076 } else { 3077 if (c->host_port != cport) 3078 continue; 3079 } 3080 if ((c->listening_addr == NULL && addr != NULL) || 3081 (c->listening_addr != NULL && addr == NULL)) 3082 continue; 3083 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { 3084 debug2("%s: close channel %d", __func__, i); 3085 channel_free(c); 3086 found = 1; 3087 } 3088 } 3089 3090 return (found); 3091 } 3092 3093 static int 3094 channel_cancel_lport_listener_streamlocal(const char *path) 3095 { 3096 u_int i; 3097 int found = 0; 3098 3099 if (path == NULL) { 3100 error("%s: no path specified.", __func__); 3101 return 0; 3102 } 3103 3104 for (i = 0; i < channels_alloc; i++) { 3105 Channel *c = channels[i]; 3106 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) 3107 continue; 3108 if (c->listening_addr == NULL) 3109 continue; 3110 if (strcmp(c->listening_addr, path) == 0) { 3111 debug2("%s: close channel %d", __func__, i); 3112 channel_free(c); 3113 found = 1; 3114 } 3115 } 3116 3117 return (found); 3118 } 3119 3120 int 3121 channel_cancel_lport_listener(struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) 3122 { 3123 if (fwd->listen_path != NULL) 3124 return channel_cancel_lport_listener_streamlocal(fwd->listen_path); 3125 else 3126 return channel_cancel_lport_listener_tcpip(fwd->listen_host, fwd->listen_port, cport, fwd_opts); 3127 } 3128 3129 /* protocol local port fwd, used by ssh (and sshd in v1) */ 3130 int 3131 channel_setup_local_fwd_listener(struct Forward *fwd, struct ForwardOptions *fwd_opts) 3132 { 3133 if (fwd->listen_path != NULL) { 3134 return channel_setup_fwd_listener_streamlocal( 3135 SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); 3136 } else { 3137 return channel_setup_fwd_listener_tcpip(SSH_CHANNEL_PORT_LISTENER, 3138 fwd, NULL, fwd_opts); 3139 } 3140 } 3141 3142 /* protocol v2 remote port fwd, used by sshd */ 3143 int 3144 channel_setup_remote_fwd_listener(struct Forward *fwd, 3145 int *allocated_listen_port, struct ForwardOptions *fwd_opts) 3146 { 3147 if (fwd->listen_path != NULL) { 3148 return channel_setup_fwd_listener_streamlocal( 3149 SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); 3150 } else { 3151 return channel_setup_fwd_listener_tcpip( 3152 SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, 3153 fwd_opts); 3154 } 3155 } 3156 3157 /* 3158 * Translate the requested rfwd listen host to something usable for 3159 * this server. 3160 */ 3161 static const char * 3162 channel_rfwd_bind_host(const char *listen_host) 3163 { 3164 if (listen_host == NULL) { 3165 if (datafellows & SSH_BUG_RFWD_ADDR) 3166 return "127.0.0.1"; 3167 else 3168 return "localhost"; 3169 } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { 3170 if (datafellows & SSH_BUG_RFWD_ADDR) 3171 return "0.0.0.0"; 3172 else 3173 return ""; 3174 } else 3175 return listen_host; 3176 } 3177 3178 /* 3179 * Initiate forwarding of connections to port "port" on remote host through 3180 * the secure channel to host:port from local side. 3181 * Returns handle (index) for updating the dynamic listen port with 3182 * channel_update_permitted_opens(). 3183 */ 3184 int 3185 channel_request_remote_forwarding(struct Forward *fwd) 3186 { 3187 int type, success = 0, idx = -1; 3188 3189 /* Send the forward request to the remote side. */ 3190 if (compat20) { 3191 packet_start(SSH2_MSG_GLOBAL_REQUEST); 3192 if (fwd->listen_path != NULL) { 3193 packet_put_cstring("streamlocal-forward@openssh.com"); 3194 packet_put_char(1); /* boolean: want reply */ 3195 packet_put_cstring(fwd->listen_path); 3196 } else { 3197 packet_put_cstring("tcpip-forward"); 3198 packet_put_char(1); /* boolean: want reply */ 3199 packet_put_cstring(channel_rfwd_bind_host(fwd->listen_host)); 3200 packet_put_int(fwd->listen_port); 3201 } 3202 packet_send(); 3203 packet_write_wait(); 3204 /* Assume that server accepts the request */ 3205 success = 1; 3206 } else if (fwd->listen_path == NULL) { 3207 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); 3208 packet_put_int(fwd->listen_port); 3209 packet_put_cstring(fwd->connect_host); 3210 packet_put_int(fwd->connect_port); 3211 packet_send(); 3212 packet_write_wait(); 3213 3214 /* Wait for response from the remote side. */ 3215 type = packet_read(); 3216 switch (type) { 3217 case SSH_SMSG_SUCCESS: 3218 success = 1; 3219 break; 3220 case SSH_SMSG_FAILURE: 3221 break; 3222 default: 3223 /* Unknown packet */ 3224 packet_disconnect("Protocol error for port forward request:" 3225 "received packet type %d.", type); 3226 } 3227 } else { 3228 logit("Warning: Server does not support remote stream local forwarding."); 3229 } 3230 if (success) { 3231 /* Record that connection to this host/port is permitted. */ 3232 permitted_opens = xreallocarray(permitted_opens, 3233 num_permitted_opens + 1, sizeof(*permitted_opens)); 3234 idx = num_permitted_opens++; 3235 if (fwd->connect_path != NULL) { 3236 permitted_opens[idx].host_to_connect = 3237 xstrdup(fwd->connect_path); 3238 permitted_opens[idx].port_to_connect = 3239 PORT_STREAMLOCAL; 3240 } else { 3241 permitted_opens[idx].host_to_connect = 3242 xstrdup(fwd->connect_host); 3243 permitted_opens[idx].port_to_connect = 3244 fwd->connect_port; 3245 } 3246 if (fwd->listen_path != NULL) { 3247 permitted_opens[idx].listen_host = NULL; 3248 permitted_opens[idx].listen_path = 3249 xstrdup(fwd->listen_path); 3250 permitted_opens[idx].listen_port = PORT_STREAMLOCAL; 3251 } else { 3252 permitted_opens[idx].listen_host = 3253 fwd->listen_host ? xstrdup(fwd->listen_host) : NULL; 3254 permitted_opens[idx].listen_path = NULL; 3255 permitted_opens[idx].listen_port = fwd->listen_port; 3256 } 3257 } 3258 return (idx); 3259 } 3260 3261 static int 3262 open_match(ForwardPermission *allowed_open, const char *requestedhost, 3263 int requestedport) 3264 { 3265 if (allowed_open->host_to_connect == NULL) 3266 return 0; 3267 if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && 3268 allowed_open->port_to_connect != requestedport) 3269 return 0; 3270 if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && 3271 strcmp(allowed_open->host_to_connect, requestedhost) != 0) 3272 return 0; 3273 return 1; 3274 } 3275 3276 /* 3277 * Note that in the listen host/port case 3278 * we don't support FWD_PERMIT_ANY_PORT and 3279 * need to translate between the configured-host (listen_host) 3280 * and what we've sent to the remote server (channel_rfwd_bind_host) 3281 */ 3282 static int 3283 open_listen_match_tcpip(ForwardPermission *allowed_open, 3284 const char *requestedhost, u_short requestedport, int translate) 3285 { 3286 const char *allowed_host; 3287 3288 if (allowed_open->host_to_connect == NULL) 3289 return 0; 3290 if (allowed_open->listen_port != requestedport) 3291 return 0; 3292 if (!translate && allowed_open->listen_host == NULL && 3293 requestedhost == NULL) 3294 return 1; 3295 allowed_host = translate ? 3296 channel_rfwd_bind_host(allowed_open->listen_host) : 3297 allowed_open->listen_host; 3298 if (allowed_host == NULL || 3299 strcmp(allowed_host, requestedhost) != 0) 3300 return 0; 3301 return 1; 3302 } 3303 3304 static int 3305 open_listen_match_streamlocal(ForwardPermission *allowed_open, 3306 const char *requestedpath) 3307 { 3308 if (allowed_open->host_to_connect == NULL) 3309 return 0; 3310 if (allowed_open->listen_port != PORT_STREAMLOCAL) 3311 return 0; 3312 if (allowed_open->listen_path == NULL || 3313 strcmp(allowed_open->listen_path, requestedpath) != 0) 3314 return 0; 3315 return 1; 3316 } 3317 3318 /* 3319 * Request cancellation of remote forwarding of connection host:port from 3320 * local side. 3321 */ 3322 static int 3323 channel_request_rforward_cancel_tcpip(const char *host, u_short port) 3324 { 3325 int i; 3326 3327 if (!compat20) 3328 return -1; 3329 3330 for (i = 0; i < num_permitted_opens; i++) { 3331 if (open_listen_match_tcpip(&permitted_opens[i], host, port, 0)) 3332 break; 3333 } 3334 if (i >= num_permitted_opens) { 3335 debug("%s: requested forward not found", __func__); 3336 return -1; 3337 } 3338 packet_start(SSH2_MSG_GLOBAL_REQUEST); 3339 packet_put_cstring("cancel-tcpip-forward"); 3340 packet_put_char(0); 3341 packet_put_cstring(channel_rfwd_bind_host(host)); 3342 packet_put_int(port); 3343 packet_send(); 3344 3345 permitted_opens[i].listen_port = 0; 3346 permitted_opens[i].port_to_connect = 0; 3347 free(permitted_opens[i].host_to_connect); 3348 permitted_opens[i].host_to_connect = NULL; 3349 free(permitted_opens[i].listen_host); 3350 permitted_opens[i].listen_host = NULL; 3351 permitted_opens[i].listen_path = NULL; 3352 3353 return 0; 3354 } 3355 3356 /* 3357 * Request cancellation of remote forwarding of Unix domain socket 3358 * path from local side. 3359 */ 3360 static int 3361 channel_request_rforward_cancel_streamlocal(const char *path) 3362 { 3363 int i; 3364 3365 if (!compat20) 3366 return -1; 3367 3368 for (i = 0; i < num_permitted_opens; i++) { 3369 if (open_listen_match_streamlocal(&permitted_opens[i], path)) 3370 break; 3371 } 3372 if (i >= num_permitted_opens) { 3373 debug("%s: requested forward not found", __func__); 3374 return -1; 3375 } 3376 packet_start(SSH2_MSG_GLOBAL_REQUEST); 3377 packet_put_cstring("cancel-streamlocal-forward@openssh.com"); 3378 packet_put_char(0); 3379 packet_put_cstring(path); 3380 packet_send(); 3381 3382 permitted_opens[i].listen_port = 0; 3383 permitted_opens[i].port_to_connect = 0; 3384 free(permitted_opens[i].host_to_connect); 3385 permitted_opens[i].host_to_connect = NULL; 3386 permitted_opens[i].listen_host = NULL; 3387 free(permitted_opens[i].listen_path); 3388 permitted_opens[i].listen_path = NULL; 3389 3390 return 0; 3391 } 3392 3393 /* 3394 * Request cancellation of remote forwarding of a connection from local side. 3395 */ 3396 int 3397 channel_request_rforward_cancel(struct Forward *fwd) 3398 { 3399 if (fwd->listen_path != NULL) { 3400 return (channel_request_rforward_cancel_streamlocal( 3401 fwd->listen_path)); 3402 } else { 3403 return (channel_request_rforward_cancel_tcpip(fwd->listen_host, 3404 fwd->listen_port ? fwd->listen_port : fwd->allocated_port)); 3405 } 3406 } 3407 3408 /* 3409 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates 3410 * listening for the port, and sends back a success reply (or disconnect 3411 * message if there was an error). 3412 */ 3413 int 3414 channel_input_port_forward_request(int is_root, struct ForwardOptions *fwd_opts) 3415 { 3416 int success = 0; 3417 struct Forward fwd; 3418 3419 /* Get arguments from the packet. */ 3420 memset(&fwd, 0, sizeof(fwd)); 3421 fwd.listen_port = packet_get_int(); 3422 fwd.connect_host = packet_get_string(NULL); 3423 fwd.connect_port = packet_get_int(); 3424 3425 /* 3426 * Check that an unprivileged user is not trying to forward a 3427 * privileged port. 3428 */ 3429 if (fwd.listen_port < IPPORT_RESERVED && !is_root) 3430 packet_disconnect( 3431 "Requested forwarding of port %d but user is not root.", 3432 fwd.listen_port); 3433 if (fwd.connect_port == 0) 3434 packet_disconnect("Dynamic forwarding denied."); 3435 3436 /* Initiate forwarding */ 3437 success = channel_setup_local_fwd_listener(&fwd, fwd_opts); 3438 3439 /* Free the argument string. */ 3440 free(fwd.connect_host); 3441 3442 return (success ? 0 : -1); 3443 } 3444 3445 /* 3446 * Permits opening to any host/port if permitted_opens[] is empty. This is 3447 * usually called by the server, because the user could connect to any port 3448 * anyway, and the server has no way to know but to trust the client anyway. 3449 */ 3450 void 3451 channel_permit_all_opens(void) 3452 { 3453 if (num_permitted_opens == 0) 3454 all_opens_permitted = 1; 3455 } 3456 3457 void 3458 channel_add_permitted_opens(char *host, int port) 3459 { 3460 debug("allow port forwarding to host %s port %d", host, port); 3461 3462 permitted_opens = xreallocarray(permitted_opens, 3463 num_permitted_opens + 1, sizeof(*permitted_opens)); 3464 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); 3465 permitted_opens[num_permitted_opens].port_to_connect = port; 3466 permitted_opens[num_permitted_opens].listen_host = NULL; 3467 permitted_opens[num_permitted_opens].listen_path = NULL; 3468 permitted_opens[num_permitted_opens].listen_port = 0; 3469 num_permitted_opens++; 3470 3471 all_opens_permitted = 0; 3472 } 3473 3474 /* 3475 * Update the listen port for a dynamic remote forward, after 3476 * the actual 'newport' has been allocated. If 'newport' < 0 is 3477 * passed then they entry will be invalidated. 3478 */ 3479 void 3480 channel_update_permitted_opens(int idx, int newport) 3481 { 3482 if (idx < 0 || idx >= num_permitted_opens) { 3483 debug("channel_update_permitted_opens: index out of range:" 3484 " %d num_permitted_opens %d", idx, num_permitted_opens); 3485 return; 3486 } 3487 debug("%s allowed port %d for forwarding to host %s port %d", 3488 newport > 0 ? "Updating" : "Removing", 3489 newport, 3490 permitted_opens[idx].host_to_connect, 3491 permitted_opens[idx].port_to_connect); 3492 if (newport >= 0) { 3493 permitted_opens[idx].listen_port = 3494 (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; 3495 } else { 3496 permitted_opens[idx].listen_port = 0; 3497 permitted_opens[idx].port_to_connect = 0; 3498 free(permitted_opens[idx].host_to_connect); 3499 permitted_opens[idx].host_to_connect = NULL; 3500 free(permitted_opens[idx].listen_host); 3501 permitted_opens[idx].listen_host = NULL; 3502 free(permitted_opens[idx].listen_path); 3503 permitted_opens[idx].listen_path = NULL; 3504 } 3505 } 3506 3507 int 3508 channel_add_adm_permitted_opens(char *host, int port) 3509 { 3510 debug("config allows port forwarding to host %s port %d", host, port); 3511 3512 permitted_adm_opens = xreallocarray(permitted_adm_opens, 3513 num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens)); 3514 permitted_adm_opens[num_adm_permitted_opens].host_to_connect 3515 = xstrdup(host); 3516 permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port; 3517 permitted_adm_opens[num_adm_permitted_opens].listen_host = NULL; 3518 permitted_adm_opens[num_adm_permitted_opens].listen_path = NULL; 3519 permitted_adm_opens[num_adm_permitted_opens].listen_port = 0; 3520 return ++num_adm_permitted_opens; 3521 } 3522 3523 void 3524 channel_disable_adm_local_opens(void) 3525 { 3526 channel_clear_adm_permitted_opens(); 3527 permitted_adm_opens = xcalloc(sizeof(*permitted_adm_opens), 1); 3528 permitted_adm_opens[num_adm_permitted_opens].host_to_connect = NULL; 3529 num_adm_permitted_opens = 1; 3530 } 3531 3532 void 3533 channel_clear_permitted_opens(void) 3534 { 3535 int i; 3536 3537 for (i = 0; i < num_permitted_opens; i++) { 3538 free(permitted_opens[i].host_to_connect); 3539 free(permitted_opens[i].listen_host); 3540 free(permitted_opens[i].listen_path); 3541 } 3542 free(permitted_opens); 3543 permitted_opens = NULL; 3544 num_permitted_opens = 0; 3545 } 3546 3547 void 3548 channel_clear_adm_permitted_opens(void) 3549 { 3550 int i; 3551 3552 for (i = 0; i < num_adm_permitted_opens; i++) { 3553 free(permitted_adm_opens[i].host_to_connect); 3554 free(permitted_adm_opens[i].listen_host); 3555 free(permitted_adm_opens[i].listen_path); 3556 } 3557 free(permitted_adm_opens); 3558 permitted_adm_opens = NULL; 3559 num_adm_permitted_opens = 0; 3560 } 3561 3562 void 3563 channel_print_adm_permitted_opens(void) 3564 { 3565 int i; 3566 3567 printf("permitopen"); 3568 if (num_adm_permitted_opens == 0) { 3569 printf(" any\n"); 3570 return; 3571 } 3572 for (i = 0; i < num_adm_permitted_opens; i++) 3573 if (permitted_adm_opens[i].host_to_connect == NULL) 3574 printf(" none"); 3575 else 3576 printf(" %s:%d", permitted_adm_opens[i].host_to_connect, 3577 permitted_adm_opens[i].port_to_connect); 3578 printf("\n"); 3579 } 3580 3581 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ 3582 int 3583 permitopen_port(const char *p) 3584 { 3585 int port; 3586 3587 if (strcmp(p, "*") == 0) 3588 return FWD_PERMIT_ANY_PORT; 3589 if ((port = a2port(p)) > 0) 3590 return port; 3591 return -1; 3592 } 3593 3594 /* Try to start non-blocking connect to next host in cctx list */ 3595 static int 3596 connect_next(struct channel_connect *cctx) 3597 { 3598 int sock, saved_errno; 3599 struct sockaddr_un *sunaddr; 3600 char ntop[NI_MAXHOST], strport[MAXIMUM(NI_MAXSERV,sizeof(sunaddr->sun_path))]; 3601 3602 for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { 3603 switch (cctx->ai->ai_family) { 3604 case AF_UNIX: 3605 /* unix:pathname instead of host:port */ 3606 sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; 3607 strlcpy(ntop, "unix", sizeof(ntop)); 3608 strlcpy(strport, sunaddr->sun_path, sizeof(strport)); 3609 break; 3610 case AF_INET: 3611 case AF_INET6: 3612 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, 3613 ntop, sizeof(ntop), strport, sizeof(strport), 3614 NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 3615 error("connect_next: getnameinfo failed"); 3616 continue; 3617 } 3618 break; 3619 default: 3620 continue; 3621 } 3622 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, 3623 cctx->ai->ai_protocol)) == -1) { 3624 if (cctx->ai->ai_next == NULL) 3625 error("socket: %.100s", strerror(errno)); 3626 else 3627 verbose("socket: %.100s", strerror(errno)); 3628 continue; 3629 } 3630 if (set_nonblock(sock) == -1) 3631 fatal("%s: set_nonblock(%d)", __func__, sock); 3632 if (connect(sock, cctx->ai->ai_addr, 3633 cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { 3634 debug("connect_next: host %.100s ([%.100s]:%s): " 3635 "%.100s", cctx->host, ntop, strport, 3636 strerror(errno)); 3637 saved_errno = errno; 3638 close(sock); 3639 errno = saved_errno; 3640 continue; /* fail -- try next */ 3641 } 3642 if (cctx->ai->ai_family != AF_UNIX) 3643 set_nodelay(sock); 3644 debug("connect_next: host %.100s ([%.100s]:%s) " 3645 "in progress, fd=%d", cctx->host, ntop, strport, sock); 3646 cctx->ai = cctx->ai->ai_next; 3647 return sock; 3648 } 3649 return -1; 3650 } 3651 3652 static void 3653 channel_connect_ctx_free(struct channel_connect *cctx) 3654 { 3655 free(cctx->host); 3656 if (cctx->aitop) { 3657 if (cctx->aitop->ai_family == AF_UNIX) 3658 free(cctx->aitop); 3659 else 3660 freeaddrinfo(cctx->aitop); 3661 } 3662 memset(cctx, 0, sizeof(*cctx)); 3663 } 3664 3665 /* Return CONNECTING channel to remote host:port or local socket path */ 3666 static Channel * 3667 connect_to(const char *name, int port, char *ctype, char *rname) 3668 { 3669 struct addrinfo hints; 3670 int gaierr; 3671 int sock = -1; 3672 char strport[NI_MAXSERV]; 3673 struct channel_connect cctx; 3674 Channel *c; 3675 3676 memset(&cctx, 0, sizeof(cctx)); 3677 3678 if (port == PORT_STREAMLOCAL) { 3679 struct sockaddr_un *sunaddr; 3680 struct addrinfo *ai; 3681 3682 if (strlen(name) > sizeof(sunaddr->sun_path)) { 3683 error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); 3684 return (NULL); 3685 } 3686 3687 /* 3688 * Fake up a struct addrinfo for AF_UNIX connections. 3689 * channel_connect_ctx_free() must check ai_family 3690 * and use free() not freeaddirinfo() for AF_UNIX. 3691 */ 3692 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); 3693 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); 3694 ai->ai_addr = (struct sockaddr *)(ai + 1); 3695 ai->ai_addrlen = sizeof(*sunaddr); 3696 ai->ai_family = AF_UNIX; 3697 ai->ai_socktype = SOCK_STREAM; 3698 ai->ai_protocol = PF_UNSPEC; 3699 sunaddr = (struct sockaddr_un *)ai->ai_addr; 3700 sunaddr->sun_family = AF_UNIX; 3701 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); 3702 cctx.aitop = ai; 3703 } else { 3704 memset(&hints, 0, sizeof(hints)); 3705 hints.ai_family = IPv4or6; 3706 hints.ai_socktype = SOCK_STREAM; 3707 snprintf(strport, sizeof strport, "%d", port); 3708 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx.aitop)) != 0) { 3709 error("connect_to %.100s: unknown host (%s)", name, 3710 ssh_gai_strerror(gaierr)); 3711 return NULL; 3712 } 3713 } 3714 3715 cctx.host = xstrdup(name); 3716 cctx.port = port; 3717 cctx.ai = cctx.aitop; 3718 3719 if ((sock = connect_next(&cctx)) == -1) { 3720 error("connect to %.100s port %d failed: %s", 3721 name, port, strerror(errno)); 3722 channel_connect_ctx_free(&cctx); 3723 return NULL; 3724 } 3725 c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, 3726 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); 3727 c->connect_ctx = cctx; 3728 return c; 3729 } 3730 3731 Channel * 3732 channel_connect_by_listen_address(const char *listen_host, 3733 u_short listen_port, char *ctype, char *rname) 3734 { 3735 int i; 3736 3737 for (i = 0; i < num_permitted_opens; i++) { 3738 if (open_listen_match_tcpip(&permitted_opens[i], listen_host, 3739 listen_port, 1)) { 3740 return connect_to( 3741 permitted_opens[i].host_to_connect, 3742 permitted_opens[i].port_to_connect, ctype, rname); 3743 } 3744 } 3745 error("WARNING: Server requests forwarding for unknown listen_port %d", 3746 listen_port); 3747 return NULL; 3748 } 3749 3750 Channel * 3751 channel_connect_by_listen_path(const char *path, char *ctype, char *rname) 3752 { 3753 int i; 3754 3755 for (i = 0; i < num_permitted_opens; i++) { 3756 if (open_listen_match_streamlocal(&permitted_opens[i], path)) { 3757 return connect_to( 3758 permitted_opens[i].host_to_connect, 3759 permitted_opens[i].port_to_connect, ctype, rname); 3760 } 3761 } 3762 error("WARNING: Server requests forwarding for unknown path %.100s", 3763 path); 3764 return NULL; 3765 } 3766 3767 /* Check if connecting to that port is permitted and connect. */ 3768 Channel * 3769 channel_connect_to_port(const char *host, u_short port, char *ctype, char *rname) 3770 { 3771 int i, permit, permit_adm = 1; 3772 3773 permit = all_opens_permitted; 3774 if (!permit) { 3775 for (i = 0; i < num_permitted_opens; i++) 3776 if (open_match(&permitted_opens[i], host, port)) { 3777 permit = 1; 3778 break; 3779 } 3780 } 3781 3782 if (num_adm_permitted_opens > 0) { 3783 permit_adm = 0; 3784 for (i = 0; i < num_adm_permitted_opens; i++) 3785 if (open_match(&permitted_adm_opens[i], host, port)) { 3786 permit_adm = 1; 3787 break; 3788 } 3789 } 3790 3791 if (!permit || !permit_adm) { 3792 logit("Received request to connect to host %.100s port %d, " 3793 "but the request was denied.", host, port); 3794 return NULL; 3795 } 3796 return connect_to(host, port, ctype, rname); 3797 } 3798 3799 /* Check if connecting to that path is permitted and connect. */ 3800 Channel * 3801 channel_connect_to_path(const char *path, char *ctype, char *rname) 3802 { 3803 int i, permit, permit_adm = 1; 3804 3805 permit = all_opens_permitted; 3806 if (!permit) { 3807 for (i = 0; i < num_permitted_opens; i++) 3808 if (open_match(&permitted_opens[i], path, PORT_STREAMLOCAL)) { 3809 permit = 1; 3810 break; 3811 } 3812 } 3813 3814 if (num_adm_permitted_opens > 0) { 3815 permit_adm = 0; 3816 for (i = 0; i < num_adm_permitted_opens; i++) 3817 if (open_match(&permitted_adm_opens[i], path, PORT_STREAMLOCAL)) { 3818 permit_adm = 1; 3819 break; 3820 } 3821 } 3822 3823 if (!permit || !permit_adm) { 3824 logit("Received request to connect to path %.100s, " 3825 "but the request was denied.", path); 3826 return NULL; 3827 } 3828 return connect_to(path, PORT_STREAMLOCAL, ctype, rname); 3829 } 3830 3831 void 3832 channel_send_window_changes(void) 3833 { 3834 u_int i; 3835 struct winsize ws; 3836 3837 for (i = 0; i < channels_alloc; i++) { 3838 if (channels[i] == NULL || !channels[i]->client_tty || 3839 channels[i]->type != SSH_CHANNEL_OPEN) 3840 continue; 3841 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) 3842 continue; 3843 channel_request_start(i, "window-change", 0); 3844 packet_put_int((u_int)ws.ws_col); 3845 packet_put_int((u_int)ws.ws_row); 3846 packet_put_int((u_int)ws.ws_xpixel); 3847 packet_put_int((u_int)ws.ws_ypixel); 3848 packet_send(); 3849 } 3850 } 3851 3852 /* -- X11 forwarding */ 3853 3854 /* 3855 * Creates an internet domain socket for listening for X11 connections. 3856 * Returns 0 and a suitable display number for the DISPLAY variable 3857 * stored in display_numberp , or -1 if an error occurs. 3858 */ 3859 int 3860 x11_create_display_inet(int x11_display_offset, int x11_use_localhost, 3861 int single_connection, u_int *display_numberp, int **chanids) 3862 { 3863 Channel *nc = NULL; 3864 int display_number, sock; 3865 u_short port; 3866 struct addrinfo hints, *ai, *aitop; 3867 char strport[NI_MAXSERV]; 3868 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 3869 3870 if (chanids == NULL) 3871 return -1; 3872 3873 for (display_number = x11_display_offset; 3874 display_number < MAX_DISPLAYS; 3875 display_number++) { 3876 port = 6000 + display_number; 3877 memset(&hints, 0, sizeof(hints)); 3878 hints.ai_family = IPv4or6; 3879 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; 3880 hints.ai_socktype = SOCK_STREAM; 3881 snprintf(strport, sizeof strport, "%d", port); 3882 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { 3883 error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); 3884 return -1; 3885 } 3886 for (ai = aitop; ai; ai = ai->ai_next) { 3887 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 3888 continue; 3889 sock = socket(ai->ai_family, ai->ai_socktype, 3890 ai->ai_protocol); 3891 if (sock < 0) { 3892 error("socket: %.100s", strerror(errno)); 3893 freeaddrinfo(aitop); 3894 return -1; 3895 } 3896 channel_set_reuseaddr(sock); 3897 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 3898 debug2("bind port %d: %.100s", port, strerror(errno)); 3899 close(sock); 3900 3901 for (n = 0; n < num_socks; n++) { 3902 close(socks[n]); 3903 } 3904 num_socks = 0; 3905 break; 3906 } 3907 socks[num_socks++] = sock; 3908 if (num_socks == NUM_SOCKS) 3909 break; 3910 } 3911 freeaddrinfo(aitop); 3912 if (num_socks > 0) 3913 break; 3914 } 3915 if (display_number >= MAX_DISPLAYS) { 3916 error("Failed to allocate internet-domain X11 display socket."); 3917 return -1; 3918 } 3919 /* Start listening for connections on the socket. */ 3920 for (n = 0; n < num_socks; n++) { 3921 sock = socks[n]; 3922 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 3923 error("listen: %.100s", strerror(errno)); 3924 close(sock); 3925 return -1; 3926 } 3927 } 3928 3929 /* Allocate a channel for each socket. */ 3930 *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); 3931 for (n = 0; n < num_socks; n++) { 3932 sock = socks[n]; 3933 nc = channel_new("x11 listener", 3934 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 3935 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 3936 0, "X11 inet listener", 1); 3937 nc->single_connection = single_connection; 3938 (*chanids)[n] = nc->self; 3939 } 3940 (*chanids)[n] = -1; 3941 3942 /* Return the display number for the DISPLAY environment variable. */ 3943 *display_numberp = display_number; 3944 return (0); 3945 } 3946 3947 static int 3948 connect_local_xsocket(u_int dnr) 3949 { 3950 int sock; 3951 struct sockaddr_un addr; 3952 3953 sock = socket(AF_UNIX, SOCK_STREAM, 0); 3954 if (sock < 0) 3955 error("socket: %.100s", strerror(errno)); 3956 memset(&addr, 0, sizeof(addr)); 3957 addr.sun_family = AF_UNIX; 3958 snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); 3959 if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) 3960 return sock; 3961 close(sock); 3962 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 3963 return -1; 3964 } 3965 3966 int 3967 x11_connect_display(void) 3968 { 3969 u_int display_number; 3970 const char *display; 3971 char buf[1024], *cp; 3972 struct addrinfo hints, *ai, *aitop; 3973 char strport[NI_MAXSERV]; 3974 int gaierr, sock = 0; 3975 3976 /* Try to open a socket for the local X server. */ 3977 display = getenv("DISPLAY"); 3978 if (!display) { 3979 error("DISPLAY not set."); 3980 return -1; 3981 } 3982 /* 3983 * Now we decode the value of the DISPLAY variable and make a 3984 * connection to the real X server. 3985 */ 3986 3987 /* 3988 * Check if it is a unix domain socket. Unix domain displays are in 3989 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 3990 */ 3991 if (strncmp(display, "unix:", 5) == 0 || 3992 display[0] == ':') { 3993 /* Connect to the unix domain socket. */ 3994 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) { 3995 error("Could not parse display number from DISPLAY: %.100s", 3996 display); 3997 return -1; 3998 } 3999 /* Create a socket. */ 4000 sock = connect_local_xsocket(display_number); 4001 if (sock < 0) 4002 return -1; 4003 4004 /* OK, we now have a connection to the display. */ 4005 return sock; 4006 } 4007 /* 4008 * Connect to an inet socket. The DISPLAY value is supposedly 4009 * hostname:d[.s], where hostname may also be numeric IP address. 4010 */ 4011 strlcpy(buf, display, sizeof(buf)); 4012 cp = strchr(buf, ':'); 4013 if (!cp) { 4014 error("Could not find ':' in DISPLAY: %.100s", display); 4015 return -1; 4016 } 4017 *cp = 0; 4018 /* buf now contains the host name. But first we parse the display number. */ 4019 if (sscanf(cp + 1, "%u", &display_number) != 1) { 4020 error("Could not parse display number from DISPLAY: %.100s", 4021 display); 4022 return -1; 4023 } 4024 4025 /* Look up the host address */ 4026 memset(&hints, 0, sizeof(hints)); 4027 hints.ai_family = IPv4or6; 4028 hints.ai_socktype = SOCK_STREAM; 4029 snprintf(strport, sizeof strport, "%u", 6000 + display_number); 4030 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 4031 error("%.100s: unknown host. (%s)", buf, 4032 ssh_gai_strerror(gaierr)); 4033 return -1; 4034 } 4035 for (ai = aitop; ai; ai = ai->ai_next) { 4036 /* Create a socket. */ 4037 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); 4038 if (sock < 0) { 4039 debug2("socket: %.100s", strerror(errno)); 4040 continue; 4041 } 4042 /* Connect it to the display. */ 4043 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 4044 debug2("connect %.100s port %u: %.100s", buf, 4045 6000 + display_number, strerror(errno)); 4046 close(sock); 4047 continue; 4048 } 4049 /* Success */ 4050 break; 4051 } 4052 freeaddrinfo(aitop); 4053 if (!ai) { 4054 error("connect %.100s port %u: %.100s", buf, 6000 + display_number, 4055 strerror(errno)); 4056 return -1; 4057 } 4058 set_nodelay(sock); 4059 return sock; 4060 } 4061 4062 /* 4063 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains 4064 * the remote channel number. We should do whatever we want, and respond 4065 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. 4066 */ 4067 4068 /* ARGSUSED */ 4069 int 4070 x11_input_open(int type, u_int32_t seq, void *ctxt) 4071 { 4072 Channel *c = NULL; 4073 int remote_id, sock = 0; 4074 char *remote_host; 4075 4076 debug("Received X11 open request."); 4077 4078 remote_id = packet_get_int(); 4079 4080 if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { 4081 remote_host = packet_get_string(NULL); 4082 } else { 4083 remote_host = xstrdup("unknown (remote did not supply name)"); 4084 } 4085 packet_check_eom(); 4086 4087 /* Obtain a connection to the real X display. */ 4088 sock = x11_connect_display(); 4089 if (sock != -1) { 4090 /* Allocate a channel for this connection. */ 4091 c = channel_new("connected x11 socket", 4092 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, 4093 remote_host, 1); 4094 c->remote_id = remote_id; 4095 c->force_drain = 1; 4096 } 4097 free(remote_host); 4098 if (c == NULL) { 4099 /* Send refusal to the remote host. */ 4100 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 4101 packet_put_int(remote_id); 4102 } else { 4103 /* Send a confirmation to the remote host. */ 4104 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 4105 packet_put_int(remote_id); 4106 packet_put_int(c->self); 4107 } 4108 packet_send(); 4109 return 0; 4110 } 4111 4112 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ 4113 /* ARGSUSED */ 4114 int 4115 deny_input_open(int type, u_int32_t seq, void *ctxt) 4116 { 4117 int rchan = packet_get_int(); 4118 4119 switch (type) { 4120 case SSH_SMSG_AGENT_OPEN: 4121 error("Warning: ssh server tried agent forwarding."); 4122 break; 4123 case SSH_SMSG_X11_OPEN: 4124 error("Warning: ssh server tried X11 forwarding."); 4125 break; 4126 default: 4127 error("deny_input_open: type %d", type); 4128 break; 4129 } 4130 error("Warning: this is probably a break-in attempt by a malicious server."); 4131 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 4132 packet_put_int(rchan); 4133 packet_send(); 4134 return 0; 4135 } 4136 4137 /* 4138 * Requests forwarding of X11 connections, generates fake authentication 4139 * data, and enables authentication spoofing. 4140 * This should be called in the client only. 4141 */ 4142 void 4143 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp, 4144 const char *proto, const char *data, int want_reply) 4145 { 4146 u_int data_len = (u_int) strlen(data) / 2; 4147 u_int i, value; 4148 char *new_data; 4149 int screen_number; 4150 const char *cp; 4151 4152 if (x11_saved_display == NULL) 4153 x11_saved_display = xstrdup(disp); 4154 else if (strcmp(disp, x11_saved_display) != 0) { 4155 error("x11_request_forwarding_with_spoofing: different " 4156 "$DISPLAY already forwarded"); 4157 return; 4158 } 4159 4160 cp = strchr(disp, ':'); 4161 if (cp) 4162 cp = strchr(cp, '.'); 4163 if (cp) 4164 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); 4165 else 4166 screen_number = 0; 4167 4168 if (x11_saved_proto == NULL) { 4169 /* Save protocol name. */ 4170 x11_saved_proto = xstrdup(proto); 4171 4172 /* Extract real authentication data. */ 4173 x11_saved_data = xmalloc(data_len); 4174 for (i = 0; i < data_len; i++) { 4175 if (sscanf(data + 2 * i, "%2x", &value) != 1) 4176 fatal("x11_request_forwarding: bad " 4177 "authentication data: %.100s", data); 4178 x11_saved_data[i] = value; 4179 } 4180 x11_saved_data_len = data_len; 4181 4182 /* Generate fake data of the same length. */ 4183 x11_fake_data = xmalloc(data_len); 4184 arc4random_buf(x11_fake_data, data_len); 4185 x11_fake_data_len = data_len; 4186 } 4187 4188 /* Convert the fake data into hex. */ 4189 new_data = tohex(x11_fake_data, data_len); 4190 4191 /* Send the request packet. */ 4192 if (compat20) { 4193 channel_request_start(client_session_id, "x11-req", want_reply); 4194 packet_put_char(0); /* XXX bool single connection */ 4195 } else { 4196 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); 4197 } 4198 packet_put_cstring(proto); 4199 packet_put_cstring(new_data); 4200 packet_put_int(screen_number); 4201 packet_send(); 4202 packet_write_wait(); 4203 free(new_data); 4204 } 4205 4206 4207 /* -- agent forwarding */ 4208 4209 /* Sends a message to the server to request authentication fd forwarding. */ 4210 4211 void 4212 auth_request_forwarding(void) 4213 { 4214 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); 4215 packet_send(); 4216 packet_write_wait(); 4217 } 4218