channels.c revision 60573
121259Swollman/* 221259Swollman * 321259Swollman * channels.c 421259Swollman * 521259Swollman * Author: Tatu Ylonen <ylo@cs.hut.fi> 621259Swollman * 721259Swollman * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 821259Swollman * All rights reserved 921259Swollman * 1021259Swollman * Created: Fri Mar 24 16:35:24 1995 ylo 1121259Swollman * 1221259Swollman * This file contains functions for generic socket connection forwarding. 1321259Swollman * There is also code for initiating connection forwarding for X11 connections, 1421259Swollman * arbitrary tcp/ip connections, and the authentication agent connection. 1521259Swollman * 1621259Swollman * SSH2 support added by Markus Friedl. 1721259Swollman */ 1821259Swollman 1921259Swollman#include "includes.h" 2021259SwollmanRCSID("$Id: channels.c,v 1.57 2000/05/08 17:42:24 markus Exp $"); 2121259Swollman 2221259Swollman#include "ssh.h" 2321259Swollman#include "packet.h" 2421259Swollman#include "xmalloc.h" 2521259Swollman#include "buffer.h" 2621259Swollman#include "authfd.h" 2721259Swollman#include "uidswap.h" 2821259Swollman#include "readconf.h" 2921259Swollman#include "servconf.h" 3021259Swollman 3121259Swollman#include "channels.h" 3221259Swollman#include "nchan.h" 3321259Swollman#include "compat.h" 3421404Swollman 3521259Swollman#include "ssh2.h" 3621259Swollman 3721259Swollman/* Maximum number of fake X11 displays to try. */ 3821259Swollman#define MAX_DISPLAYS 1000 3921259Swollman 4021259Swollman/* Max len of agent socket */ 4121259Swollman#define MAX_SOCKET_NAME 100 4221259Swollman 4321259Swollman/* default window/packet sizes for tcp/x11-fwd-channel */ 4421259Swollman#define CHAN_TCP_WINDOW_DEFAULT (8*1024) 4521259Swollman#define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2) 4621259Swollman#define CHAN_X11_WINDOW_DEFAULT (4*1024) 4721259Swollman#define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2) 4821259Swollman 4921259Swollman/* 5021259Swollman * Pointer to an array containing all allocated channels. The array is 5121259Swollman * dynamically extended as needed. 5221259Swollman */ 5321259Swollmanstatic Channel *channels = NULL; 5421259Swollman 5521259Swollman/* 5621259Swollman * Size of the channel array. All slots of the array must always be 5721259Swollman * initialized (at least the type field); unused slots are marked with type 5821259Swollman * SSH_CHANNEL_FREE. 5921259Swollman */ 6021259Swollmanstatic int channels_alloc = 0; 6121259Swollman 6221259Swollman/* 6321259Swollman * Maximum file descriptor value used in any of the channels. This is 6421259Swollman * updated in channel_allocate. 6521259Swollman */ 6621259Swollmanstatic int channel_max_fd_value = 0; 6721259Swollman 6821259Swollman/* Name and directory of socket for authentication agent forwarding. */ 6921259Swollmanstatic char *channel_forwarded_auth_socket_name = NULL; 7021259Swollmanstatic char *channel_forwarded_auth_socket_dir = NULL; 7121259Swollman 7221259Swollman/* Saved X11 authentication protocol name. */ 7321259Swollmanchar *x11_saved_proto = NULL; 7421259Swollman 7521259Swollman/* Saved X11 authentication data. This is the real data. */ 7621259Swollmanchar *x11_saved_data = NULL; 7721259Swollmanunsigned int x11_saved_data_len = 0; 7821259Swollman 7921259Swollman/* 8021404Swollman * Fake X11 authentication data. This is what the server will be sending us; 8121259Swollman * we should replace any occurrences of this by the real data. 8221259Swollman */ 8321259Swollmanchar *x11_fake_data = NULL; 8421259Swollmanunsigned int x11_fake_data_len; 8521259Swollman 8621259Swollman/* 8721259Swollman * Data structure for storing which hosts are permitted for forward requests. 8821259Swollman * The local sides of any remote forwards are stored in this array to prevent 8921259Swollman * a corrupt remote server from accessing arbitrary TCP/IP ports on our local 9021259Swollman * network (which might be behind a firewall). 9121259Swollman */ 9221259Swollmantypedef struct { 9321259Swollman char *host_to_connect; /* Connect to 'host'. */ 9421259Swollman u_short port_to_connect; /* Connect to 'port'. */ 9521259Swollman u_short listen_port; /* Remote side should listen port number. */ 9621259Swollman} ForwardPermission; 9721259Swollman 9821259Swollman/* List of all permitted host/port pairs to connect. */ 9921259Swollmanstatic ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; 10021259Swollman/* Number of permitted host/port pairs in the array. */ 10121259Swollmanstatic int num_permitted_opens = 0; 10221259Swollman/* 10321259Swollman * If this is true, all opens are permitted. This is the case on the server 10421259Swollman * on which we have to trust the client anyway, and the user could do 10521259Swollman * anything after logging in anyway. 10621259Swollman */ 10721259Swollmanstatic int all_opens_permitted = 0; 10821259Swollman 10921259Swollman/* This is set to true if both sides support SSH_PROTOFLAG_HOST_IN_FWD_OPEN. */ 11021259Swollmanstatic int have_hostname_in_open = 0; 11121259Swollman 11221259Swollman/* Sets specific protocol options. */ 11321404Swollman 11421404Swollmanvoid 11521259Swollmanchannel_set_options(int hostname_in_open) 11621259Swollman{ 11721259Swollman have_hostname_in_open = hostname_in_open; 11821259Swollman} 11921259Swollman 12021259Swollman/* 12121259Swollman * Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually 12221259Swollman * called by the server, because the user could connect to any port anyway, 12321259Swollman * and the server has no way to know but to trust the client anyway. 12421259Swollman */ 12521259Swollman 12621259Swollmanvoid 12721259Swollmanchannel_permit_all_opens() 12821259Swollman{ 12921259Swollman all_opens_permitted = 1; 13021259Swollman} 13121259Swollman 13221259Swollman/* lookup channel by id */ 13321259Swollman 13421259SwollmanChannel * 13521259Swollmanchannel_lookup(int id) 13621259Swollman{ 13721404Swollman Channel *c; 13821404Swollman if (id < 0 && id > channels_alloc) { 13921259Swollman log("channel_lookup: %d: bad id", id); 14021259Swollman return NULL; 14121259Swollman } 14221259Swollman c = &channels[id]; 14321259Swollman if (c->type == SSH_CHANNEL_FREE) { 14421259Swollman log("channel_lookup: %d: bad id: channel free", id); 14521259Swollman return NULL; 14621259Swollman } 14721259Swollman return c; 14821259Swollman} 14921259Swollman 15021259Swollmanvoid 15121259Swollmanset_nonblock(int fd) 15221259Swollman{ 15321259Swollman int val; 15421259Swollman val = fcntl(fd, F_GETFL, 0); 15521259Swollman if (val < 0) { 15621259Swollman error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno)); 15721259Swollman return; 15821259Swollman } 15921259Swollman if (val & O_NONBLOCK) 16021259Swollman return; 16121259Swollman debug("fd %d setting O_NONBLOCK", fd); 16221259Swollman val |= O_NONBLOCK; 16321259Swollman if (fcntl(fd, F_SETFL, val) == -1) 16421259Swollman error("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd, strerror(errno)); 16521259Swollman} 16621259Swollman 16721259Swollman/* 16821259Swollman * Register filedescriptors for a channel, used when allocating a channel or 16921259Swollman * when the channel consumer/producer is ready, e.g. shell exec'd 17021259Swollman */ 17121259Swollman 17221259Swollmanvoid 17321259Swollmanchannel_register_fds(Channel *c, int rfd, int wfd, int efd, int extusage) 17421259Swollman{ 17521259Swollman /* Update the maximum file descriptor value. */ 17621259Swollman if (rfd > channel_max_fd_value) 17721259Swollman channel_max_fd_value = rfd; 17821259Swollman if (wfd > channel_max_fd_value) 17921259Swollman channel_max_fd_value = wfd; 18021259Swollman if (efd > channel_max_fd_value) 18121259Swollman channel_max_fd_value = efd; 18221259Swollman /* XXX set close-on-exec -markus */ 18321259Swollman 18421259Swollman c->rfd = rfd; 18521259Swollman c->wfd = wfd; 18621259Swollman c->sock = (rfd == wfd) ? rfd : -1; 18721259Swollman c->efd = efd; 18821259Swollman c->extended_usage = extusage; 18921259Swollman if (rfd != -1) 19021259Swollman set_nonblock(rfd); 19121259Swollman if (wfd != -1) 19221259Swollman set_nonblock(wfd); 19321259Swollman if (efd != -1) 19421259Swollman set_nonblock(efd); 19521259Swollman} 19621259Swollman 19721259Swollman/* 19821259Swollman * Allocate a new channel object and set its type and socket. This will cause 19921259Swollman * remote_name to be freed. 20021259Swollman */ 20121259Swollman 20221259Swollmanint 20321259Swollmanchannel_new(char *ctype, int type, int rfd, int wfd, int efd, 20421259Swollman int window, int maxpack, int extusage, char *remote_name) 20521259Swollman{ 20621259Swollman int i, found; 20721259Swollman Channel *c; 20821259Swollman 20921259Swollman /* Do initial allocation if this is the first call. */ 21021259Swollman if (channels_alloc == 0) { 21121259Swollman chan_init(); 21221259Swollman channels_alloc = 10; 21321259Swollman channels = xmalloc(channels_alloc * sizeof(Channel)); 21421259Swollman for (i = 0; i < channels_alloc; i++) 21521259Swollman channels[i].type = SSH_CHANNEL_FREE; 21621259Swollman /* 21721259Swollman * Kludge: arrange a call to channel_stop_listening if we 21821259Swollman * terminate with fatal(). 21921259Swollman */ 22021259Swollman fatal_add_cleanup((void (*) (void *)) channel_stop_listening, NULL); 22121259Swollman } 22221259Swollman /* Try to find a free slot where to put the new channel. */ 22321259Swollman for (found = -1, i = 0; i < channels_alloc; i++) 22421259Swollman if (channels[i].type == SSH_CHANNEL_FREE) { 22521259Swollman /* Found a free slot. */ 22621259Swollman found = i; 22721259Swollman break; 22821259Swollman } 22921259Swollman if (found == -1) { 23021259Swollman /* There are no free slots. Take last+1 slot and expand the array. */ 23121259Swollman found = channels_alloc; 23221259Swollman channels_alloc += 10; 23321259Swollman debug("channel: expanding %d", channels_alloc); 23421259Swollman channels = xrealloc(channels, channels_alloc * sizeof(Channel)); 23521259Swollman for (i = found; i < channels_alloc; i++) 23621259Swollman channels[i].type = SSH_CHANNEL_FREE; 23721259Swollman } 23821259Swollman /* Initialize and return new channel number. */ 23921259Swollman c = &channels[found]; 24021259Swollman buffer_init(&c->input); 24121259Swollman buffer_init(&c->output); 24221259Swollman buffer_init(&c->extended); 24321259Swollman chan_init_iostates(c); 24421259Swollman channel_register_fds(c, rfd, wfd, efd, extusage); 24521259Swollman c->self = found; 24621259Swollman c->type = type; 24721259Swollman c->ctype = ctype; 24821259Swollman c->local_window = window; 24921259Swollman c->local_window_max = window; 25021259Swollman c->local_consumed = 0; 25121259Swollman c->local_maxpacket = maxpack; 25221259Swollman c->remote_id = -1; 25321259Swollman c->remote_name = remote_name; 25421259Swollman c->remote_window = 0; 25521259Swollman c->remote_maxpacket = 0; 25621259Swollman c->cb_fn = NULL; 25721259Swollman c->cb_arg = NULL; 25821259Swollman c->cb_event = 0; 25921259Swollman c->dettach_user = NULL; 26021404Swollman debug("channel %d: new [%s]", found, remote_name); 26121404Swollman return found; 26221404Swollman} 26321404Swollman/* old interface XXX */ 26421404Swollmanint 26521404Swollmanchannel_allocate(int type, int sock, char *remote_name) 26621404Swollman{ 26721404Swollman return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name); 26821404Swollman} 26921404Swollman 27021404Swollman 27121404Swollman/* Close all channel fd/socket. */ 27221404Swollman 27321404Swollmanvoid 27421259Swollmanchannel_close_fds(Channel *c) 27521259Swollman{ 27621259Swollman if (c->sock != -1) { 27721259Swollman close(c->sock); 27821259Swollman c->sock = -1; 27921259Swollman } 28021259Swollman if (c->rfd != -1) { 28121259Swollman close(c->rfd); 28221259Swollman c->rfd = -1; 28321259Swollman } 28421259Swollman if (c->wfd != -1) { 28521259Swollman close(c->wfd); 28621259Swollman c->wfd = -1; 28721259Swollman } 28821259Swollman if (c->efd != -1) { 28921259Swollman close(c->efd); 29021259Swollman c->efd = -1; 29121259Swollman } 29221259Swollman} 29321404Swollman 29421404Swollman/* Free the channel and close its fd/socket. */ 29521259Swollman 29621404Swollmanvoid 29721259Swollmanchannel_free(int id) 29821259Swollman{ 29921259Swollman Channel *c = channel_lookup(id); 30021259Swollman if (c == NULL) 30121259Swollman packet_disconnect("channel free: bad local channel %d", id); 30221259Swollman debug("channel_free: channel %d: status: %s", id, channel_open_message()); 30321259Swollman if (c->dettach_user != NULL) { 30421259Swollman debug("channel_free: channel %d: dettaching channel user", id); 30521259Swollman c->dettach_user(c->self, NULL); 30621259Swollman } 30721259Swollman if (c->sock != -1) 30821259Swollman shutdown(c->sock, SHUT_RDWR); 30921259Swollman channel_close_fds(c); 31021259Swollman buffer_free(&c->input); 31121259Swollman buffer_free(&c->output); 31221259Swollman buffer_free(&c->extended); 31321259Swollman c->type = SSH_CHANNEL_FREE; 31421259Swollman if (c->remote_name) { 31521259Swollman xfree(c->remote_name); 31621259Swollman c->remote_name = NULL; 31721259Swollman } 31821259Swollman} 31921259Swollman 32021259Swollman/* 32121259Swollman * 'channel_pre*' are called just before select() to add any bits relevant to 32221259Swollman * channels in the select bitmasks. 32321259Swollman */ 32421259Swollman/* 32521259Swollman * 'channel_post*': perform any appropriate operations for channels which 32621259Swollman * have events pending. 32721259Swollman */ 328typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset); 329chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; 330chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; 331 332void 333channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset) 334{ 335 FD_SET(c->sock, readset); 336} 337 338void 339channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset) 340{ 341 if (buffer_len(&c->input) < packet_get_maxsize()) 342 FD_SET(c->sock, readset); 343 if (buffer_len(&c->output) > 0) 344 FD_SET(c->sock, writeset); 345} 346 347void 348channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset) 349{ 350 /* test whether sockets are 'alive' for read/write */ 351 if (c->istate == CHAN_INPUT_OPEN) 352 if (buffer_len(&c->input) < packet_get_maxsize()) 353 FD_SET(c->sock, readset); 354 if (c->ostate == CHAN_OUTPUT_OPEN || 355 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 356 if (buffer_len(&c->output) > 0) { 357 FD_SET(c->sock, writeset); 358 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 359 chan_obuf_empty(c); 360 } 361 } 362} 363 364void 365channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset) 366{ 367 if (c->istate == CHAN_INPUT_OPEN && 368 c->remote_window > 0 && 369 buffer_len(&c->input) < c->remote_window) 370 FD_SET(c->rfd, readset); 371 if (c->ostate == CHAN_OUTPUT_OPEN || 372 c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 373 if (buffer_len(&c->output) > 0) { 374 FD_SET(c->wfd, writeset); 375 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { 376 chan_obuf_empty(c); 377 } 378 } 379 /** XXX check close conditions, too */ 380 if (c->efd != -1) { 381 if (c->extended_usage == CHAN_EXTENDED_WRITE && 382 buffer_len(&c->extended) > 0) 383 FD_SET(c->efd, writeset); 384 else if (c->extended_usage == CHAN_EXTENDED_READ && 385 buffer_len(&c->extended) < c->remote_window) 386 FD_SET(c->efd, readset); 387 } 388} 389 390void 391channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset) 392{ 393 if (buffer_len(&c->input) == 0) { 394 packet_start(SSH_MSG_CHANNEL_CLOSE); 395 packet_put_int(c->remote_id); 396 packet_send(); 397 c->type = SSH_CHANNEL_CLOSED; 398 debug("Closing channel %d after input drain.", c->self); 399 } 400} 401 402void 403channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset) 404{ 405 if (buffer_len(&c->output) == 0) 406 channel_free(c->self); 407 else 408 FD_SET(c->sock, writeset); 409} 410 411/* 412 * This is a special state for X11 authentication spoofing. An opened X11 413 * connection (when authentication spoofing is being done) remains in this 414 * state until the first packet has been completely read. The authentication 415 * data in that packet is then substituted by the real data if it matches the 416 * fake data, and the channel is put into normal mode. 417 * XXX All this happens at the client side. 418 */ 419int 420x11_open_helper(Channel *c) 421{ 422 unsigned char *ucp; 423 unsigned int proto_len, data_len; 424 425 /* Check if the fixed size part of the packet is in buffer. */ 426 if (buffer_len(&c->output) < 12) 427 return 0; 428 429 /* Parse the lengths of variable-length fields. */ 430 ucp = (unsigned char *) buffer_ptr(&c->output); 431 if (ucp[0] == 0x42) { /* Byte order MSB first. */ 432 proto_len = 256 * ucp[6] + ucp[7]; 433 data_len = 256 * ucp[8] + ucp[9]; 434 } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ 435 proto_len = ucp[6] + 256 * ucp[7]; 436 data_len = ucp[8] + 256 * ucp[9]; 437 } else { 438 debug("Initial X11 packet contains bad byte order byte: 0x%x", 439 ucp[0]); 440 return -1; 441 } 442 443 /* Check if the whole packet is in buffer. */ 444 if (buffer_len(&c->output) < 445 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) 446 return 0; 447 448 /* Check if authentication protocol matches. */ 449 if (proto_len != strlen(x11_saved_proto) || 450 memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { 451 debug("X11 connection uses different authentication protocol."); 452 return -1; 453 } 454 /* Check if authentication data matches our fake data. */ 455 if (data_len != x11_fake_data_len || 456 memcmp(ucp + 12 + ((proto_len + 3) & ~3), 457 x11_fake_data, x11_fake_data_len) != 0) { 458 debug("X11 auth data does not match fake data."); 459 return -1; 460 } 461 /* Check fake data length */ 462 if (x11_fake_data_len != x11_saved_data_len) { 463 error("X11 fake_data_len %d != saved_data_len %d", 464 x11_fake_data_len, x11_saved_data_len); 465 return -1; 466 } 467 /* 468 * Received authentication protocol and data match 469 * our fake data. Substitute the fake data with real 470 * data. 471 */ 472 memcpy(ucp + 12 + ((proto_len + 3) & ~3), 473 x11_saved_data, x11_saved_data_len); 474 return 1; 475} 476 477void 478channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset) 479{ 480 int ret = x11_open_helper(c); 481 if (ret == 1) { 482 /* Start normal processing for the channel. */ 483 c->type = SSH_CHANNEL_OPEN; 484 channel_pre_open_13(c, readset, writeset); 485 } else if (ret == -1) { 486 /* 487 * We have received an X11 connection that has bad 488 * authentication information. 489 */ 490 log("X11 connection rejected because of wrong authentication.\r\n"); 491 buffer_clear(&c->input); 492 buffer_clear(&c->output); 493 close(c->sock); 494 c->sock = -1; 495 c->type = SSH_CHANNEL_CLOSED; 496 packet_start(SSH_MSG_CHANNEL_CLOSE); 497 packet_put_int(c->remote_id); 498 packet_send(); 499 } 500} 501 502void 503channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset) 504{ 505 int ret = x11_open_helper(c); 506 if (ret == 1) { 507 c->type = SSH_CHANNEL_OPEN; 508 if (compat20) 509 channel_pre_open_20(c, readset, writeset); 510 else 511 channel_pre_open_15(c, readset, writeset); 512 } else if (ret == -1) { 513 debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); 514 chan_read_failed(c); /** force close? */ 515 chan_write_failed(c); 516 debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); 517 } 518} 519 520/* This is our fake X11 server socket. */ 521void 522channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) 523{ 524 struct sockaddr addr; 525 int newsock, newch; 526 socklen_t addrlen; 527 char buf[16384], *remote_hostname; 528 int remote_port; 529 530 if (FD_ISSET(c->sock, readset)) { 531 debug("X11 connection requested."); 532 addrlen = sizeof(addr); 533 newsock = accept(c->sock, &addr, &addrlen); 534 if (newsock < 0) { 535 error("accept: %.100s", strerror(errno)); 536 return; 537 } 538 remote_hostname = get_remote_hostname(newsock); 539 remote_port = get_peer_port(newsock); 540 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", 541 remote_hostname, remote_port); 542 543 newch = channel_new("x11", 544 SSH_CHANNEL_OPENING, newsock, newsock, -1, 545 c->local_window_max, c->local_maxpacket, 546 0, xstrdup(buf)); 547 if (compat20) { 548 packet_start(SSH2_MSG_CHANNEL_OPEN); 549 packet_put_cstring("x11"); 550 packet_put_int(newch); 551 packet_put_int(c->local_window_max); 552 packet_put_int(c->local_maxpacket); 553 /* originator host and port */ 554 packet_put_cstring(remote_hostname); 555 if (datafellows & SSH_BUG_X11FWD) { 556 debug("ssh2 x11 bug compat mode"); 557 } else { 558 packet_put_int(remote_port); 559 } 560 packet_send(); 561 } else { 562 packet_start(SSH_SMSG_X11_OPEN); 563 packet_put_int(newch); 564 if (have_hostname_in_open) 565 packet_put_string(buf, strlen(buf)); 566 packet_send(); 567 } 568 xfree(remote_hostname); 569 } 570} 571 572/* 573 * This socket is listening for connections to a forwarded TCP/IP port. 574 */ 575void 576channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset) 577{ 578 struct sockaddr addr; 579 int newsock, newch; 580 socklen_t addrlen; 581 char buf[1024], *remote_hostname; 582 int remote_port; 583 584 if (FD_ISSET(c->sock, readset)) { 585 debug("Connection to port %d forwarding " 586 "to %.100s port %d requested.", 587 c->listening_port, c->path, c->host_port); 588 addrlen = sizeof(addr); 589 newsock = accept(c->sock, &addr, &addrlen); 590 if (newsock < 0) { 591 error("accept: %.100s", strerror(errno)); 592 return; 593 } 594 remote_hostname = get_remote_hostname(newsock); 595 remote_port = get_peer_port(newsock); 596 snprintf(buf, sizeof buf, 597 "listen port %d for %.100s port %d, " 598 "connect from %.200s port %d", 599 c->listening_port, c->path, c->host_port, 600 remote_hostname, remote_port); 601 newch = channel_new("direct-tcpip", 602 SSH_CHANNEL_OPENING, newsock, newsock, -1, 603 c->local_window_max, c->local_maxpacket, 604 0, xstrdup(buf)); 605 if (compat20) { 606 packet_start(SSH2_MSG_CHANNEL_OPEN); 607 packet_put_cstring("direct-tcpip"); 608 packet_put_int(newch); 609 packet_put_int(c->local_window_max); 610 packet_put_int(c->local_maxpacket); 611 /* target host and port */ 612 packet_put_string(c->path, strlen(c->path)); 613 packet_put_int(c->host_port); 614 /* originator host and port */ 615 packet_put_cstring(remote_hostname); 616 packet_put_int(remote_port); 617 packet_send(); 618 } else { 619 packet_start(SSH_MSG_PORT_OPEN); 620 packet_put_int(newch); 621 packet_put_string(c->path, strlen(c->path)); 622 packet_put_int(c->host_port); 623 if (have_hostname_in_open) { 624 packet_put_string(buf, strlen(buf)); 625 } 626 packet_send(); 627 } 628 xfree(remote_hostname); 629 } 630} 631 632/* 633 * This is the authentication agent socket listening for connections from 634 * clients. 635 */ 636void 637channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset) 638{ 639 struct sockaddr addr; 640 int newsock, newch; 641 socklen_t addrlen; 642 643 if (FD_ISSET(c->sock, readset)) { 644 addrlen = sizeof(addr); 645 newsock = accept(c->sock, &addr, &addrlen); 646 if (newsock < 0) { 647 error("accept from auth socket: %.100s", strerror(errno)); 648 return; 649 } 650 newch = channel_allocate(SSH_CHANNEL_OPENING, newsock, 651 xstrdup("accepted auth socket")); 652 packet_start(SSH_SMSG_AGENT_OPEN); 653 packet_put_int(newch); 654 packet_send(); 655 } 656} 657 658int 659channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset) 660{ 661 char buf[16*1024]; 662 int len; 663 664 if (c->rfd != -1 && 665 FD_ISSET(c->rfd, readset)) { 666 len = read(c->rfd, buf, sizeof(buf)); 667 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 668 return 1; 669 if (len <= 0) { 670 debug("channel %d: read<=0 rfd %d len %d", 671 c->self, c->rfd, len); 672 if (compat13) { 673 buffer_consume(&c->output, buffer_len(&c->output)); 674 c->type = SSH_CHANNEL_INPUT_DRAINING; 675 debug("Channel %d status set to input draining.", c->self); 676 } else { 677 chan_read_failed(c); 678 } 679 return -1; 680 } 681 buffer_append(&c->input, buf, len); 682 } 683 return 1; 684} 685int 686channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) 687{ 688 int len; 689 690 /* Send buffered output data to the socket. */ 691 if (c->wfd != -1 && 692 FD_ISSET(c->wfd, writeset) && 693 buffer_len(&c->output) > 0) { 694 len = write(c->wfd, buffer_ptr(&c->output), 695 buffer_len(&c->output)); 696 if (len < 0 && (errno == EINTR || errno == EAGAIN)) 697 return 1; 698 if (len <= 0) { 699 if (compat13) { 700 buffer_consume(&c->output, buffer_len(&c->output)); 701 debug("Channel %d status set to input draining.", c->self); 702 c->type = SSH_CHANNEL_INPUT_DRAINING; 703 } else { 704 chan_write_failed(c); 705 } 706 return -1; 707 } 708 buffer_consume(&c->output, len); 709 if (compat20 && len > 0) { 710 c->local_consumed += len; 711 } 712 } 713 return 1; 714} 715int 716channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset) 717{ 718 char buf[16*1024]; 719 int len; 720 721/** XXX handle drain efd, too */ 722 if (c->efd != -1) { 723 if (c->extended_usage == CHAN_EXTENDED_WRITE && 724 FD_ISSET(c->efd, writeset) && 725 buffer_len(&c->extended) > 0) { 726 len = write(c->efd, buffer_ptr(&c->extended), 727 buffer_len(&c->extended)); 728 debug("channel %d: written %d to efd %d", 729 c->self, len, c->efd); 730 if (len > 0) { 731 buffer_consume(&c->extended, len); 732 c->local_consumed += len; 733 } 734 } else if (c->extended_usage == CHAN_EXTENDED_READ && 735 FD_ISSET(c->efd, readset)) { 736 len = read(c->efd, buf, sizeof(buf)); 737 debug("channel %d: read %d from efd %d", 738 c->self, len, c->efd); 739 if (len == 0) { 740 debug("channel %d: closing efd %d", 741 c->self, c->efd); 742 close(c->efd); 743 c->efd = -1; 744 } else if (len > 0) 745 buffer_append(&c->extended, buf, len); 746 } 747 } 748 return 1; 749} 750int 751channel_check_window(Channel *c, fd_set * readset, fd_set * writeset) 752{ 753 if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && 754 c->local_window < c->local_window_max/2 && 755 c->local_consumed > 0) { 756 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 757 packet_put_int(c->remote_id); 758 packet_put_int(c->local_consumed); 759 packet_send(); 760 debug("channel %d: window %d sent adjust %d", 761 c->self, c->local_window, 762 c->local_consumed); 763 c->local_window += c->local_consumed; 764 c->local_consumed = 0; 765 } 766 return 1; 767} 768 769void 770channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset) 771{ 772 channel_handle_rfd(c, readset, writeset); 773 channel_handle_wfd(c, readset, writeset); 774} 775 776void 777channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset) 778{ 779 channel_handle_rfd(c, readset, writeset); 780 channel_handle_wfd(c, readset, writeset); 781 channel_handle_efd(c, readset, writeset); 782 channel_check_window(c, readset, writeset); 783} 784 785void 786channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset) 787{ 788 int len; 789 /* Send buffered output data to the socket. */ 790 if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { 791 len = write(c->sock, buffer_ptr(&c->output), 792 buffer_len(&c->output)); 793 if (len <= 0) 794 buffer_consume(&c->output, buffer_len(&c->output)); 795 else 796 buffer_consume(&c->output, len); 797 } 798} 799 800void 801channel_handler_init_20(void) 802{ 803 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20; 804 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 805 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 806 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 807 808 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2; 809 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 810 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 811} 812 813void 814channel_handler_init_13(void) 815{ 816 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; 817 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; 818 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 819 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 820 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 821 channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; 822 channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; 823 824 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1; 825 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 826 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 827 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 828 channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; 829} 830 831void 832channel_handler_init_15(void) 833{ 834 channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15; 835 channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; 836 channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; 837 channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; 838 channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; 839 840 channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; 841 channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; 842 channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; 843 channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1; 844} 845 846void 847channel_handler_init(void) 848{ 849 int i; 850 for(i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { 851 channel_pre[i] = NULL; 852 channel_post[i] = NULL; 853 } 854 if (compat20) 855 channel_handler_init_20(); 856 else if (compat13) 857 channel_handler_init_13(); 858 else 859 channel_handler_init_15(); 860} 861 862void 863channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset) 864{ 865 static int did_init = 0; 866 int i; 867 Channel *c; 868 869 if (!did_init) { 870 channel_handler_init(); 871 did_init = 1; 872 } 873 for (i = 0; i < channels_alloc; i++) { 874 c = &channels[i]; 875 if (c->type == SSH_CHANNEL_FREE) 876 continue; 877 if (ftab[c->type] == NULL) 878 continue; 879 (*ftab[c->type])(c, readset, writeset); 880 chan_delete_if_full_closed(c); 881 } 882} 883 884void 885channel_prepare_select(fd_set * readset, fd_set * writeset) 886{ 887 channel_handler(channel_pre, readset, writeset); 888} 889 890void 891channel_after_select(fd_set * readset, fd_set * writeset) 892{ 893 channel_handler(channel_post, readset, writeset); 894} 895 896/* If there is data to send to the connection, send some of it now. */ 897 898void 899channel_output_poll() 900{ 901 int len, i; 902 Channel *c; 903 904 for (i = 0; i < channels_alloc; i++) { 905 c = &channels[i]; 906 907 /* We are only interested in channels that can have buffered incoming data. */ 908 if (compat13) { 909 if (c->type != SSH_CHANNEL_OPEN && 910 c->type != SSH_CHANNEL_INPUT_DRAINING) 911 continue; 912 } else { 913 if (c->type != SSH_CHANNEL_OPEN) 914 continue; 915 if (c->istate != CHAN_INPUT_OPEN && 916 c->istate != CHAN_INPUT_WAIT_DRAIN) 917 continue; 918 } 919 if (compat20 && 920 (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { 921 debug("channel: %d: no data after CLOSE", c->self); 922 continue; 923 } 924 925 /* Get the amount of buffered data for this channel. */ 926 len = buffer_len(&c->input); 927 if (len > 0) { 928 /* Send some data for the other side over the secure connection. */ 929 if (compat20) { 930 if (len > c->remote_window) 931 len = c->remote_window; 932 if (len > c->remote_maxpacket) 933 len = c->remote_maxpacket; 934 } else { 935 if (packet_is_interactive()) { 936 if (len > 1024) 937 len = 512; 938 } else { 939 /* Keep the packets at reasonable size. */ 940 if (len > packet_get_maxsize()/2) 941 len = packet_get_maxsize()/2; 942 } 943 } 944 if (len > 0) { 945 packet_start(compat20 ? 946 SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); 947 packet_put_int(c->remote_id); 948 packet_put_string(buffer_ptr(&c->input), len); 949 packet_send(); 950 buffer_consume(&c->input, len); 951 c->remote_window -= len; 952 debug("channel %d: send data len %d", c->self, len); 953 } 954 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { 955 if (compat13) 956 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); 957 /* 958 * input-buffer is empty and read-socket shutdown: 959 * tell peer, that we will not send more data: send IEOF 960 */ 961 chan_ibuf_empty(c); 962 } 963 /* Send extended data, i.e. stderr */ 964 if (compat20 && 965 c->remote_window > 0 && 966 (len = buffer_len(&c->extended)) > 0 && 967 c->extended_usage == CHAN_EXTENDED_READ) { 968 if (len > c->remote_window) 969 len = c->remote_window; 970 if (len > c->remote_maxpacket) 971 len = c->remote_maxpacket; 972 packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); 973 packet_put_int(c->remote_id); 974 packet_put_int(SSH2_EXTENDED_DATA_STDERR); 975 packet_put_string(buffer_ptr(&c->extended), len); 976 packet_send(); 977 buffer_consume(&c->extended, len); 978 c->remote_window -= len; 979 } 980 } 981} 982 983/* 984 * This is called when a packet of type CHANNEL_DATA has just been received. 985 * The message type has already been consumed, but channel number and data is 986 * still there. 987 */ 988 989void 990channel_input_data(int type, int plen) 991{ 992 int id; 993 char *data; 994 unsigned int data_len; 995 Channel *c; 996 997 /* Get the channel number and verify it. */ 998 id = packet_get_int(); 999 c = channel_lookup(id); 1000 if (c == NULL) 1001 packet_disconnect("Received data for nonexistent channel %d.", id); 1002 1003 /* Ignore any data for non-open channels (might happen on close) */ 1004 if (c->type != SSH_CHANNEL_OPEN && 1005 c->type != SSH_CHANNEL_X11_OPEN) 1006 return; 1007 1008 /* same for protocol 1.5 if output end is no longer open */ 1009 if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) 1010 return; 1011 1012 /* Get the data. */ 1013 data = packet_get_string(&data_len); 1014 packet_done(); 1015 1016 if (compat20){ 1017 if (data_len > c->local_maxpacket) { 1018 log("channel %d: rcvd big packet %d, maxpack %d", 1019 c->self, data_len, c->local_maxpacket); 1020 } 1021 if (data_len > c->local_window) { 1022 log("channel %d: rcvd too much data %d, win %d", 1023 c->self, data_len, c->local_window); 1024 xfree(data); 1025 return; 1026 } 1027 c->local_window -= data_len; 1028 }else{ 1029 packet_integrity_check(plen, 4 + 4 + data_len, type); 1030 } 1031 buffer_append(&c->output, data, data_len); 1032 xfree(data); 1033} 1034void 1035channel_input_extended_data(int type, int plen) 1036{ 1037 int id; 1038 int tcode; 1039 char *data; 1040 unsigned int data_len; 1041 Channel *c; 1042 1043 /* Get the channel number and verify it. */ 1044 id = packet_get_int(); 1045 c = channel_lookup(id); 1046 1047 if (c == NULL) 1048 packet_disconnect("Received extended_data for bad channel %d.", id); 1049 if (c->type != SSH_CHANNEL_OPEN) { 1050 log("channel %d: ext data for non open", id); 1051 return; 1052 } 1053 tcode = packet_get_int(); 1054 if (c->efd == -1 || 1055 c->extended_usage != CHAN_EXTENDED_WRITE || 1056 tcode != SSH2_EXTENDED_DATA_STDERR) { 1057 log("channel %d: bad ext data", c->self); 1058 return; 1059 } 1060 data = packet_get_string(&data_len); 1061 packet_done(); 1062 if (data_len > c->local_window) { 1063 log("channel %d: rcvd too much extended_data %d, win %d", 1064 c->self, data_len, c->local_window); 1065 xfree(data); 1066 return; 1067 } 1068 debug("channel %d: rcvd ext data %d", c->self, data_len); 1069 c->local_window -= data_len; 1070 buffer_append(&c->extended, data, data_len); 1071 xfree(data); 1072} 1073 1074 1075/* 1076 * Returns true if no channel has too much buffered data, and false if one or 1077 * more channel is overfull. 1078 */ 1079 1080int 1081channel_not_very_much_buffered_data() 1082{ 1083 unsigned int i; 1084 Channel *c; 1085 1086 for (i = 0; i < channels_alloc; i++) { 1087 c = &channels[i]; 1088 if (c->type == SSH_CHANNEL_OPEN) { 1089 if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) { 1090 debug("channel %d: big input buffer %d", 1091 c->self, buffer_len(&c->input)); 1092 return 0; 1093 } 1094 if (buffer_len(&c->output) > packet_get_maxsize()) { 1095 debug("channel %d: big output buffer %d", 1096 c->self, buffer_len(&c->output)); 1097 return 0; 1098 } 1099 } 1100 } 1101 return 1; 1102} 1103 1104void 1105channel_input_ieof(int type, int plen) 1106{ 1107 int id; 1108 Channel *c; 1109 1110 packet_integrity_check(plen, 4, type); 1111 1112 id = packet_get_int(); 1113 c = channel_lookup(id); 1114 if (c == NULL) 1115 packet_disconnect("Received ieof for nonexistent channel %d.", id); 1116 chan_rcvd_ieof(c); 1117} 1118 1119void 1120channel_input_close(int type, int plen) 1121{ 1122 int id; 1123 Channel *c; 1124 1125 packet_integrity_check(plen, 4, type); 1126 1127 id = packet_get_int(); 1128 c = channel_lookup(id); 1129 if (c == NULL) 1130 packet_disconnect("Received close for nonexistent channel %d.", id); 1131 1132 /* 1133 * Send a confirmation that we have closed the channel and no more 1134 * data is coming for it. 1135 */ 1136 packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); 1137 packet_put_int(c->remote_id); 1138 packet_send(); 1139 1140 /* 1141 * If the channel is in closed state, we have sent a close request, 1142 * and the other side will eventually respond with a confirmation. 1143 * Thus, we cannot free the channel here, because then there would be 1144 * no-one to receive the confirmation. The channel gets freed when 1145 * the confirmation arrives. 1146 */ 1147 if (c->type != SSH_CHANNEL_CLOSED) { 1148 /* 1149 * Not a closed channel - mark it as draining, which will 1150 * cause it to be freed later. 1151 */ 1152 buffer_consume(&c->input, buffer_len(&c->input)); 1153 c->type = SSH_CHANNEL_OUTPUT_DRAINING; 1154 } 1155} 1156 1157/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ 1158void 1159channel_input_oclose(int type, int plen) 1160{ 1161 int id = packet_get_int(); 1162 Channel *c = channel_lookup(id); 1163 packet_integrity_check(plen, 4, type); 1164 if (c == NULL) 1165 packet_disconnect("Received oclose for nonexistent channel %d.", id); 1166 chan_rcvd_oclose(c); 1167} 1168 1169void 1170channel_input_close_confirmation(int type, int plen) 1171{ 1172 int id = packet_get_int(); 1173 Channel *c = channel_lookup(id); 1174 1175 packet_done(); 1176 if (c == NULL) 1177 packet_disconnect("Received close confirmation for " 1178 "out-of-range channel %d.", id); 1179 if (c->type != SSH_CHANNEL_CLOSED) 1180 packet_disconnect("Received close confirmation for " 1181 "non-closed channel %d (type %d).", id, c->type); 1182 channel_free(c->self); 1183} 1184 1185void 1186channel_input_open_confirmation(int type, int plen) 1187{ 1188 int id, remote_id; 1189 Channel *c; 1190 1191 if (!compat20) 1192 packet_integrity_check(plen, 4 + 4, type); 1193 1194 id = packet_get_int(); 1195 c = channel_lookup(id); 1196 1197 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 1198 packet_disconnect("Received open confirmation for " 1199 "non-opening channel %d.", id); 1200 remote_id = packet_get_int(); 1201 /* Record the remote channel number and mark that the channel is now open. */ 1202 c->remote_id = remote_id; 1203 c->type = SSH_CHANNEL_OPEN; 1204 1205 if (compat20) { 1206 c->remote_window = packet_get_int(); 1207 c->remote_maxpacket = packet_get_int(); 1208 packet_done(); 1209 if (c->cb_fn != NULL && c->cb_event == type) { 1210 debug("callback start"); 1211 c->cb_fn(c->self, c->cb_arg); 1212 debug("callback done"); 1213 } 1214 debug("channel %d: open confirm rwindow %d rmax %d", c->self, 1215 c->remote_window, c->remote_maxpacket); 1216 } 1217} 1218 1219void 1220channel_input_open_failure(int type, int plen) 1221{ 1222 int id; 1223 Channel *c; 1224 1225 if (!compat20) 1226 packet_integrity_check(plen, 4, type); 1227 1228 id = packet_get_int(); 1229 c = channel_lookup(id); 1230 1231 if (c==NULL || c->type != SSH_CHANNEL_OPENING) 1232 packet_disconnect("Received open failure for " 1233 "non-opening channel %d.", id); 1234 if (compat20) { 1235 int reason = packet_get_int(); 1236 char *msg = packet_get_string(NULL); 1237 char *lang = packet_get_string(NULL); 1238 log("channel_open_failure: %d: reason %d: %s", id, reason, msg); 1239 packet_done(); 1240 xfree(msg); 1241 xfree(lang); 1242 } 1243 /* Free the channel. This will also close the socket. */ 1244 channel_free(id); 1245} 1246 1247void 1248channel_input_channel_request(int type, int plen) 1249{ 1250 int id; 1251 Channel *c; 1252 1253 id = packet_get_int(); 1254 c = channel_lookup(id); 1255 1256 if (c == NULL || 1257 (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL)) 1258 packet_disconnect("Received request for " 1259 "non-open channel %d.", id); 1260 if (c->cb_fn != NULL && c->cb_event == type) { 1261 debug("callback start"); 1262 c->cb_fn(c->self, c->cb_arg); 1263 debug("callback done"); 1264 } else { 1265 char *service = packet_get_string(NULL); 1266 debug("channel: %d rcvd request for %s", c->self, service); 1267debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event); 1268 xfree(service); 1269 } 1270} 1271 1272void 1273channel_input_window_adjust(int type, int plen) 1274{ 1275 Channel *c; 1276 int id, adjust; 1277 1278 if (!compat20) 1279 return; 1280 1281 /* Get the channel number and verify it. */ 1282 id = packet_get_int(); 1283 c = channel_lookup(id); 1284 1285 if (c == NULL || c->type != SSH_CHANNEL_OPEN) { 1286 log("Received window adjust for " 1287 "non-open channel %d.", id); 1288 return; 1289 } 1290 adjust = packet_get_int(); 1291 packet_done(); 1292 debug("channel %d: rcvd adjust %d", id, adjust); 1293 c->remote_window += adjust; 1294} 1295 1296/* 1297 * Stops listening for channels, and removes any unix domain sockets that we 1298 * might have. 1299 */ 1300 1301void 1302channel_stop_listening() 1303{ 1304 int i; 1305 for (i = 0; i < channels_alloc; i++) { 1306 switch (channels[i].type) { 1307 case SSH_CHANNEL_AUTH_SOCKET: 1308 close(channels[i].sock); 1309 remove(channels[i].path); 1310 channel_free(i); 1311 break; 1312 case SSH_CHANNEL_PORT_LISTENER: 1313 case SSH_CHANNEL_X11_LISTENER: 1314 close(channels[i].sock); 1315 channel_free(i); 1316 break; 1317 default: 1318 break; 1319 } 1320 } 1321} 1322 1323/* 1324 * Closes the sockets/fds of all channels. This is used to close extra file 1325 * descriptors after a fork. 1326 */ 1327 1328void 1329channel_close_all() 1330{ 1331 int i; 1332 for (i = 0; i < channels_alloc; i++) 1333 if (channels[i].type != SSH_CHANNEL_FREE) 1334 channel_close_fds(&channels[i]); 1335} 1336 1337/* Returns the maximum file descriptor number used by the channels. */ 1338 1339int 1340channel_max_fd() 1341{ 1342 return channel_max_fd_value; 1343} 1344 1345/* Returns true if any channel is still open. */ 1346 1347int 1348channel_still_open() 1349{ 1350 unsigned int i; 1351 for (i = 0; i < channels_alloc; i++) 1352 switch (channels[i].type) { 1353 case SSH_CHANNEL_FREE: 1354 case SSH_CHANNEL_X11_LISTENER: 1355 case SSH_CHANNEL_PORT_LISTENER: 1356 case SSH_CHANNEL_CLOSED: 1357 case SSH_CHANNEL_AUTH_SOCKET: 1358 continue; 1359 case SSH_CHANNEL_LARVAL: 1360 if (!compat20) 1361 fatal("cannot happen: SSH_CHANNEL_LARVAL"); 1362 continue; 1363 case SSH_CHANNEL_OPENING: 1364 case SSH_CHANNEL_OPEN: 1365 case SSH_CHANNEL_X11_OPEN: 1366 return 1; 1367 case SSH_CHANNEL_INPUT_DRAINING: 1368 case SSH_CHANNEL_OUTPUT_DRAINING: 1369 if (!compat13) 1370 fatal("cannot happen: OUT_DRAIN"); 1371 return 1; 1372 default: 1373 fatal("channel_still_open: bad channel type %d", channels[i].type); 1374 /* NOTREACHED */ 1375 } 1376 return 0; 1377} 1378 1379/* 1380 * Returns a message describing the currently open forwarded connections, 1381 * suitable for sending to the client. The message contains crlf pairs for 1382 * newlines. 1383 */ 1384 1385char * 1386channel_open_message() 1387{ 1388 Buffer buffer; 1389 int i; 1390 char buf[512], *cp; 1391 1392 buffer_init(&buffer); 1393 snprintf(buf, sizeof buf, "The following connections are open:\r\n"); 1394 buffer_append(&buffer, buf, strlen(buf)); 1395 for (i = 0; i < channels_alloc; i++) { 1396 Channel *c = &channels[i]; 1397 switch (c->type) { 1398 case SSH_CHANNEL_FREE: 1399 case SSH_CHANNEL_X11_LISTENER: 1400 case SSH_CHANNEL_PORT_LISTENER: 1401 case SSH_CHANNEL_CLOSED: 1402 case SSH_CHANNEL_AUTH_SOCKET: 1403 continue; 1404 case SSH_CHANNEL_LARVAL: 1405 case SSH_CHANNEL_OPENING: 1406 case SSH_CHANNEL_OPEN: 1407 case SSH_CHANNEL_X11_OPEN: 1408 case SSH_CHANNEL_INPUT_DRAINING: 1409 case SSH_CHANNEL_OUTPUT_DRAINING: 1410 snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n", 1411 c->self, c->remote_name, 1412 c->type, c->remote_id, 1413 c->istate, buffer_len(&c->input), 1414 c->ostate, buffer_len(&c->output), 1415 c->rfd, c->wfd); 1416 buffer_append(&buffer, buf, strlen(buf)); 1417 continue; 1418 default: 1419 fatal("channel_open_message: bad channel type %d", c->type); 1420 /* NOTREACHED */ 1421 } 1422 } 1423 buffer_append(&buffer, "\0", 1); 1424 cp = xstrdup(buffer_ptr(&buffer)); 1425 buffer_free(&buffer); 1426 return cp; 1427} 1428 1429/* 1430 * Initiate forwarding of connections to local port "port" through the secure 1431 * channel to host:port from remote side. 1432 */ 1433 1434void 1435channel_request_local_forwarding(u_short port, const char *host, 1436 u_short host_port, int gateway_ports) 1437{ 1438 int success, ch, sock, on = 1; 1439 struct addrinfo hints, *ai, *aitop; 1440 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 1441 struct linger linger; 1442 1443 if (strlen(host) > sizeof(channels[0].path) - 1) 1444 packet_disconnect("Forward host name too long."); 1445 1446 /* 1447 * getaddrinfo returns a loopback address if the hostname is 1448 * set to NULL and hints.ai_flags is not AI_PASSIVE 1449 */ 1450 memset(&hints, 0, sizeof(hints)); 1451 hints.ai_family = IPv4or6; 1452 hints.ai_flags = gateway_ports ? AI_PASSIVE : 0; 1453 hints.ai_socktype = SOCK_STREAM; 1454 snprintf(strport, sizeof strport, "%d", port); 1455 if (getaddrinfo(NULL, strport, &hints, &aitop) != 0) 1456 packet_disconnect("getaddrinfo: fatal error"); 1457 1458 success = 0; 1459 for (ai = aitop; ai; ai = ai->ai_next) { 1460 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 1461 continue; 1462 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 1463 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 1464 error("channel_request_local_forwarding: getnameinfo failed"); 1465 continue; 1466 } 1467 /* Create a port to listen for the host. */ 1468 sock = socket(ai->ai_family, SOCK_STREAM, 0); 1469 if (sock < 0) { 1470 /* this is no error since kernel may not support ipv6 */ 1471 verbose("socket: %.100s", strerror(errno)); 1472 continue; 1473 } 1474 /* 1475 * Set socket options. We would like the socket to disappear 1476 * as soon as it has been closed for whatever reason. 1477 */ 1478 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); 1479 linger.l_onoff = 1; 1480 linger.l_linger = 5; 1481 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger)); 1482 debug("Local forwarding listening on %s port %s.", ntop, strport); 1483 1484 /* Bind the socket to the address. */ 1485 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1486 /* address can be in use ipv6 address is already bound */ 1487 verbose("bind: %.100s", strerror(errno)); 1488 close(sock); 1489 continue; 1490 } 1491 /* Start listening for connections on the socket. */ 1492 if (listen(sock, 5) < 0) { 1493 error("listen: %.100s", strerror(errno)); 1494 close(sock); 1495 continue; 1496 } 1497 /* Allocate a channel number for the socket. */ 1498 ch = channel_new( 1499 "port listener", SSH_CHANNEL_PORT_LISTENER, 1500 sock, sock, -1, 1501 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 1502 0, xstrdup("port listener")); 1503 strlcpy(channels[ch].path, host, sizeof(channels[ch].path)); 1504 channels[ch].host_port = host_port; 1505 channels[ch].listening_port = port; 1506 success = 1; 1507 } 1508 if (success == 0) 1509 packet_disconnect("cannot listen port: %d", port); 1510 freeaddrinfo(aitop); 1511} 1512 1513/* 1514 * Initiate forwarding of connections to port "port" on remote host through 1515 * the secure channel to host:port from local side. 1516 */ 1517 1518void 1519channel_request_remote_forwarding(u_short listen_port, const char *host_to_connect, 1520 u_short port_to_connect) 1521{ 1522 int payload_len; 1523 /* Record locally that connection to this host/port is permitted. */ 1524 if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) 1525 fatal("channel_request_remote_forwarding: too many forwards"); 1526 1527 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); 1528 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; 1529 permitted_opens[num_permitted_opens].listen_port = listen_port; 1530 num_permitted_opens++; 1531 1532 /* Send the forward request to the remote side. */ 1533 if (compat20) { 1534 const char *address_to_bind = "0.0.0.0"; 1535 packet_start(SSH2_MSG_GLOBAL_REQUEST); 1536 packet_put_cstring("tcpip-forward"); 1537 packet_put_char(0); /* boolean: want reply */ 1538 packet_put_cstring(address_to_bind); 1539 packet_put_int(listen_port); 1540 } else { 1541 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); 1542 packet_put_int(listen_port); 1543 packet_put_cstring(host_to_connect); 1544 packet_put_int(port_to_connect); 1545 packet_send(); 1546 packet_write_wait(); 1547 /* 1548 * Wait for response from the remote side. It will send a disconnect 1549 * message on failure, and we will never see it here. 1550 */ 1551 packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); 1552 } 1553} 1554 1555/* 1556 * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates 1557 * listening for the port, and sends back a success reply (or disconnect 1558 * message if there was an error). This never returns if there was an error. 1559 */ 1560 1561void 1562channel_input_port_forward_request(int is_root, int gateway_ports) 1563{ 1564 u_short port, host_port; 1565 char *hostname; 1566 1567 /* Get arguments from the packet. */ 1568 port = packet_get_int(); 1569 hostname = packet_get_string(NULL); 1570 host_port = packet_get_int(); 1571 1572 /* 1573 * Check that an unprivileged user is not trying to forward a 1574 * privileged port. 1575 */ 1576 if (port < IPPORT_RESERVED && !is_root) 1577 packet_disconnect("Requested forwarding of port %d but user is not root.", 1578 port); 1579 /* 1580 * Initiate forwarding, 1581 */ 1582 channel_request_local_forwarding(port, hostname, host_port, gateway_ports); 1583 1584 /* Free the argument string. */ 1585 xfree(hostname); 1586} 1587 1588/* XXX move to aux.c */ 1589int 1590channel_connect_to(const char *host, u_short host_port) 1591{ 1592 struct addrinfo hints, *ai, *aitop; 1593 char ntop[NI_MAXHOST], strport[NI_MAXSERV]; 1594 int gaierr; 1595 int sock = -1; 1596 1597 memset(&hints, 0, sizeof(hints)); 1598 hints.ai_family = IPv4or6; 1599 hints.ai_socktype = SOCK_STREAM; 1600 snprintf(strport, sizeof strport, "%d", host_port); 1601 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { 1602 error("%.100s: unknown host (%s)", host, gai_strerror(gaierr)); 1603 return -1; 1604 } 1605 for (ai = aitop; ai; ai = ai->ai_next) { 1606 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 1607 continue; 1608 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), 1609 strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { 1610 error("channel_connect_to: getnameinfo failed"); 1611 continue; 1612 } 1613 /* Create the socket. */ 1614 sock = socket(ai->ai_family, SOCK_STREAM, 0); 1615 if (sock < 0) { 1616 error("socket: %.100s", strerror(errno)); 1617 continue; 1618 } 1619 /* Connect to the host/port. */ 1620 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1621 error("connect %.100s port %s: %.100s", ntop, strport, 1622 strerror(errno)); 1623 close(sock); 1624 continue; /* fail -- try next */ 1625 } 1626 break; /* success */ 1627 1628 } 1629 freeaddrinfo(aitop); 1630 if (!ai) { 1631 error("connect %.100s port %d: failed.", host, host_port); 1632 return -1; 1633 } 1634 /* success */ 1635 return sock; 1636} 1637/* 1638 * This is called after receiving PORT_OPEN message. This attempts to 1639 * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION 1640 * or CHANNEL_OPEN_FAILURE. 1641 */ 1642 1643void 1644channel_input_port_open(int type, int plen) 1645{ 1646 u_short host_port; 1647 char *host, *originator_string; 1648 int remote_channel, sock = -1, newch, i, denied; 1649 unsigned int host_len, originator_len; 1650 1651 /* Get remote channel number. */ 1652 remote_channel = packet_get_int(); 1653 1654 /* Get host name to connect to. */ 1655 host = packet_get_string(&host_len); 1656 1657 /* Get port to connect to. */ 1658 host_port = packet_get_int(); 1659 1660 /* Get remote originator name. */ 1661 if (have_hostname_in_open) { 1662 originator_string = packet_get_string(&originator_len); 1663 originator_len += 4; /* size of packet_int */ 1664 } else { 1665 originator_string = xstrdup("unknown (remote did not supply name)"); 1666 originator_len = 0; /* no originator supplied */ 1667 } 1668 1669 packet_integrity_check(plen, 1670 4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN); 1671 1672 /* Check if opening that port is permitted. */ 1673 denied = 0; 1674 if (!all_opens_permitted) { 1675 /* Go trough all permitted ports. */ 1676 for (i = 0; i < num_permitted_opens; i++) 1677 if (permitted_opens[i].port_to_connect == host_port && 1678 strcmp(permitted_opens[i].host_to_connect, host) == 0) 1679 break; 1680 1681 /* Check if we found the requested port among those permitted. */ 1682 if (i >= num_permitted_opens) { 1683 /* The port is not permitted. */ 1684 log("Received request to connect to %.100s:%d, but the request was denied.", 1685 host, host_port); 1686 denied = 1; 1687 } 1688 } 1689 sock = denied ? -1 : channel_connect_to(host, host_port); 1690 if (sock > 0) { 1691 /* Allocate a channel for this connection. */ 1692 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string); 1693 channels[newch].remote_id = remote_channel; 1694 1695 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1696 packet_put_int(remote_channel); 1697 packet_put_int(newch); 1698 packet_send(); 1699 } else { 1700 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1701 packet_put_int(remote_channel); 1702 packet_send(); 1703 } 1704 xfree(host); 1705} 1706 1707/* 1708 * Creates an internet domain socket for listening for X11 connections. 1709 * Returns a suitable value for the DISPLAY variable, or NULL if an error 1710 * occurs. 1711 */ 1712 1713#define NUM_SOCKS 10 1714 1715char * 1716x11_create_display_inet(int screen_number, int x11_display_offset) 1717{ 1718 int display_number, sock; 1719 u_short port; 1720 struct addrinfo hints, *ai, *aitop; 1721 char strport[NI_MAXSERV]; 1722 int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; 1723 char display[512]; 1724 char hostname[MAXHOSTNAMELEN]; 1725 1726 for (display_number = x11_display_offset; 1727 display_number < MAX_DISPLAYS; 1728 display_number++) { 1729 port = 6000 + display_number; 1730 memset(&hints, 0, sizeof(hints)); 1731 hints.ai_family = IPv4or6; 1732 hints.ai_flags = AI_PASSIVE; /* XXX loopback only ? */ 1733 hints.ai_socktype = SOCK_STREAM; 1734 snprintf(strport, sizeof strport, "%d", port); 1735 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { 1736 error("getaddrinfo: %.100s", gai_strerror(gaierr)); 1737 return NULL; 1738 } 1739 for (ai = aitop; ai; ai = ai->ai_next) { 1740 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) 1741 continue; 1742 sock = socket(ai->ai_family, SOCK_STREAM, 0); 1743 if (sock < 0) { 1744 error("socket: %.100s", strerror(errno)); 1745 return NULL; 1746 } 1747 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1748 debug("bind port %d: %.100s", port, strerror(errno)); 1749 shutdown(sock, SHUT_RDWR); 1750 close(sock); 1751 for (n = 0; n < num_socks; n++) { 1752 shutdown(socks[n], SHUT_RDWR); 1753 close(socks[n]); 1754 } 1755 num_socks = 0; 1756 break; 1757 } 1758 socks[num_socks++] = sock; 1759 if (num_socks == NUM_SOCKS) 1760 break; 1761 } 1762 if (num_socks > 0) 1763 break; 1764 } 1765 if (display_number >= MAX_DISPLAYS) { 1766 error("Failed to allocate internet-domain X11 display socket."); 1767 return NULL; 1768 } 1769 /* Start listening for connections on the socket. */ 1770 for (n = 0; n < num_socks; n++) { 1771 sock = socks[n]; 1772 if (listen(sock, 5) < 0) { 1773 error("listen: %.100s", strerror(errno)); 1774 shutdown(sock, SHUT_RDWR); 1775 close(sock); 1776 return NULL; 1777 } 1778 } 1779 1780 /* Set up a suitable value for the DISPLAY variable. */ 1781 if (gethostname(hostname, sizeof(hostname)) < 0) 1782 fatal("gethostname: %.100s", strerror(errno)); 1783 snprintf(display, sizeof display, "%.400s:%d.%d", hostname, 1784 display_number, screen_number); 1785 1786 /* Allocate a channel for each socket. */ 1787 for (n = 0; n < num_socks; n++) { 1788 sock = socks[n]; 1789 (void) channel_new("x11 listener", 1790 SSH_CHANNEL_X11_LISTENER, sock, sock, -1, 1791 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 1792 0, xstrdup("X11 inet listener")); 1793 } 1794 1795 /* Return a suitable value for the DISPLAY environment variable. */ 1796 return xstrdup(display); 1797} 1798 1799#ifndef X_UNIX_PATH 1800#define X_UNIX_PATH "/tmp/.X11-unix/X" 1801#endif 1802 1803static 1804int 1805connect_local_xsocket(unsigned int dnr) 1806{ 1807 static const char *const x_sockets[] = { 1808 X_UNIX_PATH "%u", 1809 "/var/X/.X11-unix/X" "%u", 1810 "/usr/spool/sockets/X11/" "%u", 1811 NULL 1812 }; 1813 int sock; 1814 struct sockaddr_un addr; 1815 const char *const * path; 1816 1817 for (path = x_sockets; *path; ++path) { 1818 sock = socket(AF_UNIX, SOCK_STREAM, 0); 1819 if (sock < 0) 1820 error("socket: %.100s", strerror(errno)); 1821 memset(&addr, 0, sizeof(addr)); 1822 addr.sun_family = AF_UNIX; 1823 snprintf(addr.sun_path, sizeof addr.sun_path, *path, dnr); 1824 if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0) 1825 return sock; 1826 close(sock); 1827 } 1828 error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); 1829 return -1; 1830} 1831 1832int 1833x11_connect_display(void) 1834{ 1835 int display_number, sock = 0; 1836 const char *display; 1837 char buf[1024], *cp; 1838 struct addrinfo hints, *ai, *aitop; 1839 char strport[NI_MAXSERV]; 1840 int gaierr; 1841 1842 /* Try to open a socket for the local X server. */ 1843 display = getenv("DISPLAY"); 1844 if (!display) { 1845 error("DISPLAY not set."); 1846 return -1; 1847 } 1848 /* 1849 * Now we decode the value of the DISPLAY variable and make a 1850 * connection to the real X server. 1851 */ 1852 1853 /* 1854 * Check if it is a unix domain socket. Unix domain displays are in 1855 * one of the following formats: unix:d[.s], :d[.s], ::d[.s] 1856 */ 1857 if (strncmp(display, "unix:", 5) == 0 || 1858 display[0] == ':') { 1859 /* Connect to the unix domain socket. */ 1860 if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) { 1861 error("Could not parse display number from DISPLAY: %.100s", 1862 display); 1863 return -1; 1864 } 1865 /* Create a socket. */ 1866 sock = connect_local_xsocket(display_number); 1867 if (sock < 0) 1868 return -1; 1869 1870 /* OK, we now have a connection to the display. */ 1871 return sock; 1872 } 1873 /* 1874 * Connect to an inet socket. The DISPLAY value is supposedly 1875 * hostname:d[.s], where hostname may also be numeric IP address. 1876 */ 1877 strncpy(buf, display, sizeof(buf)); 1878 buf[sizeof(buf) - 1] = 0; 1879 cp = strchr(buf, ':'); 1880 if (!cp) { 1881 error("Could not find ':' in DISPLAY: %.100s", display); 1882 return -1; 1883 } 1884 *cp = 0; 1885 /* buf now contains the host name. But first we parse the display number. */ 1886 if (sscanf(cp + 1, "%d", &display_number) != 1) { 1887 error("Could not parse display number from DISPLAY: %.100s", 1888 display); 1889 return -1; 1890 } 1891 1892 /* Look up the host address */ 1893 memset(&hints, 0, sizeof(hints)); 1894 hints.ai_family = IPv4or6; 1895 hints.ai_socktype = SOCK_STREAM; 1896 snprintf(strport, sizeof strport, "%d", 6000 + display_number); 1897 if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { 1898 error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr)); 1899 return -1; 1900 } 1901 for (ai = aitop; ai; ai = ai->ai_next) { 1902 /* Create a socket. */ 1903 sock = socket(ai->ai_family, SOCK_STREAM, 0); 1904 if (sock < 0) { 1905 debug("socket: %.100s", strerror(errno)); 1906 continue; 1907 } 1908 /* Connect it to the display. */ 1909 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { 1910 debug("connect %.100s port %d: %.100s", buf, 1911 6000 + display_number, strerror(errno)); 1912 close(sock); 1913 continue; 1914 } 1915 /* Success */ 1916 break; 1917 } 1918 freeaddrinfo(aitop); 1919 if (!ai) { 1920 error("connect %.100s port %d: %.100s", buf, 6000 + display_number, 1921 strerror(errno)); 1922 return -1; 1923 } 1924 return sock; 1925} 1926 1927/* 1928 * This is called when SSH_SMSG_X11_OPEN is received. The packet contains 1929 * the remote channel number. We should do whatever we want, and respond 1930 * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. 1931 */ 1932 1933void 1934x11_input_open(int type, int plen) 1935{ 1936 int remote_channel, sock = 0, newch; 1937 char *remote_host; 1938 unsigned int remote_len; 1939 1940 /* Get remote channel number. */ 1941 remote_channel = packet_get_int(); 1942 1943 /* Get remote originator name. */ 1944 if (have_hostname_in_open) { 1945 remote_host = packet_get_string(&remote_len); 1946 remote_len += 4; 1947 } else { 1948 remote_host = xstrdup("unknown (remote did not supply name)"); 1949 remote_len = 0; 1950 } 1951 1952 debug("Received X11 open request."); 1953 packet_integrity_check(plen, 4 + remote_len, SSH_SMSG_X11_OPEN); 1954 1955 /* Obtain a connection to the real X display. */ 1956 sock = x11_connect_display(); 1957 if (sock == -1) { 1958 /* Send refusal to the remote host. */ 1959 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1960 packet_put_int(remote_channel); 1961 packet_send(); 1962 } else { 1963 /* Allocate a channel for this connection. */ 1964 newch = channel_allocate( 1965 (x11_saved_proto == NULL) ? 1966 SSH_CHANNEL_OPEN : SSH_CHANNEL_X11_OPEN, 1967 sock, remote_host); 1968 channels[newch].remote_id = remote_channel; 1969 1970 /* Send a confirmation to the remote host. */ 1971 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1972 packet_put_int(remote_channel); 1973 packet_put_int(newch); 1974 packet_send(); 1975 } 1976} 1977 1978/* 1979 * Requests forwarding of X11 connections, generates fake authentication 1980 * data, and enables authentication spoofing. 1981 */ 1982 1983void 1984x11_request_forwarding_with_spoofing(int client_session_id, 1985 const char *proto, const char *data) 1986{ 1987 unsigned int data_len = (unsigned int) strlen(data) / 2; 1988 unsigned int i, value; 1989 char *new_data; 1990 int screen_number; 1991 const char *cp; 1992 u_int32_t rand = 0; 1993 1994 cp = getenv("DISPLAY"); 1995 if (cp) 1996 cp = strchr(cp, ':'); 1997 if (cp) 1998 cp = strchr(cp, '.'); 1999 if (cp) 2000 screen_number = atoi(cp + 1); 2001 else 2002 screen_number = 0; 2003 2004 /* Save protocol name. */ 2005 x11_saved_proto = xstrdup(proto); 2006 2007 /* 2008 * Extract real authentication data and generate fake data of the 2009 * same length. 2010 */ 2011 x11_saved_data = xmalloc(data_len); 2012 x11_fake_data = xmalloc(data_len); 2013 for (i = 0; i < data_len; i++) { 2014 if (sscanf(data + 2 * i, "%2x", &value) != 1) 2015 fatal("x11_request_forwarding: bad authentication data: %.100s", data); 2016 if (i % 4 == 0) 2017 rand = arc4random(); 2018 x11_saved_data[i] = value; 2019 x11_fake_data[i] = rand & 0xff; 2020 rand >>= 8; 2021 } 2022 x11_saved_data_len = data_len; 2023 x11_fake_data_len = data_len; 2024 2025 /* Convert the fake data into hex. */ 2026 new_data = xmalloc(2 * data_len + 1); 2027 for (i = 0; i < data_len; i++) 2028 sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]); 2029 2030 /* Send the request packet. */ 2031 if (compat20) { 2032 channel_request_start(client_session_id, "x11-req", 0); 2033 packet_put_char(0); /* XXX bool single connection */ 2034 } else { 2035 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); 2036 } 2037 packet_put_cstring(proto); 2038 packet_put_cstring(new_data); 2039 packet_put_int(screen_number); 2040 packet_send(); 2041 packet_write_wait(); 2042 xfree(new_data); 2043} 2044 2045/* Sends a message to the server to request authentication fd forwarding. */ 2046 2047void 2048auth_request_forwarding() 2049{ 2050 packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); 2051 packet_send(); 2052 packet_write_wait(); 2053} 2054 2055/* 2056 * Returns the name of the forwarded authentication socket. Returns NULL if 2057 * there is no forwarded authentication socket. The returned value points to 2058 * a static buffer. 2059 */ 2060 2061char * 2062auth_get_socket_name() 2063{ 2064 return channel_forwarded_auth_socket_name; 2065} 2066 2067/* removes the agent forwarding socket */ 2068 2069void 2070cleanup_socket(void) 2071{ 2072 remove(channel_forwarded_auth_socket_name); 2073 rmdir(channel_forwarded_auth_socket_dir); 2074} 2075 2076/* 2077 * This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. 2078 * This starts forwarding authentication requests. 2079 */ 2080 2081void 2082auth_input_request_forwarding(struct passwd * pw) 2083{ 2084 int sock, newch; 2085 struct sockaddr_un sunaddr; 2086 2087 if (auth_get_socket_name() != NULL) 2088 fatal("Protocol error: authentication forwarding requested twice."); 2089 2090 /* Temporarily drop privileged uid for mkdir/bind. */ 2091 temporarily_use_uid(pw->pw_uid); 2092 2093 /* Allocate a buffer for the socket name, and format the name. */ 2094 channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME); 2095 channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME); 2096 strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME); 2097 2098 /* Create private directory for socket */ 2099 if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL) 2100 packet_disconnect("mkdtemp: %.100s", strerror(errno)); 2101 snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d", 2102 channel_forwarded_auth_socket_dir, (int) getpid()); 2103 2104 if (atexit(cleanup_socket) < 0) { 2105 int saved = errno; 2106 cleanup_socket(); 2107 packet_disconnect("socket: %.100s", strerror(saved)); 2108 } 2109 /* Create the socket. */ 2110 sock = socket(AF_UNIX, SOCK_STREAM, 0); 2111 if (sock < 0) 2112 packet_disconnect("socket: %.100s", strerror(errno)); 2113 2114 /* Bind it to the name. */ 2115 memset(&sunaddr, 0, sizeof(sunaddr)); 2116 sunaddr.sun_family = AF_UNIX; 2117 strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name, 2118 sizeof(sunaddr.sun_path)); 2119 2120 if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) 2121 packet_disconnect("bind: %.100s", strerror(errno)); 2122 2123 /* Restore the privileged uid. */ 2124 restore_uid(); 2125 2126 /* Start listening on the socket. */ 2127 if (listen(sock, 5) < 0) 2128 packet_disconnect("listen: %.100s", strerror(errno)); 2129 2130 /* Allocate a channel for the authentication agent socket. */ 2131 newch = channel_allocate(SSH_CHANNEL_AUTH_SOCKET, sock, 2132 xstrdup("auth socket")); 2133 strlcpy(channels[newch].path, channel_forwarded_auth_socket_name, 2134 sizeof(channels[newch].path)); 2135} 2136 2137/* This is called to process an SSH_SMSG_AGENT_OPEN message. */ 2138 2139void 2140auth_input_open_request(int type, int plen) 2141{ 2142 int remch, sock, newch; 2143 char *dummyname; 2144 2145 packet_integrity_check(plen, 4, type); 2146 2147 /* Read the remote channel number from the message. */ 2148 remch = packet_get_int(); 2149 2150 /* 2151 * Get a connection to the local authentication agent (this may again 2152 * get forwarded). 2153 */ 2154 sock = ssh_get_authentication_socket(); 2155 2156 /* 2157 * If we could not connect the agent, send an error message back to 2158 * the server. This should never happen unless the agent dies, 2159 * because authentication forwarding is only enabled if we have an 2160 * agent. 2161 */ 2162 if (sock < 0) { 2163 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 2164 packet_put_int(remch); 2165 packet_send(); 2166 return; 2167 } 2168 debug("Forwarding authentication connection."); 2169 2170 /* 2171 * Dummy host name. This will be freed when the channel is freed; it 2172 * will still be valid in the packet_put_string below since the 2173 * channel cannot yet be freed at that point. 2174 */ 2175 dummyname = xstrdup("authentication agent connection"); 2176 2177 newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname); 2178 channels[newch].remote_id = remch; 2179 2180 /* Send a confirmation to the remote host. */ 2181 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 2182 packet_put_int(remch); 2183 packet_put_int(newch); 2184 packet_send(); 2185} 2186 2187void 2188channel_start_open(int id) 2189{ 2190 Channel *c = channel_lookup(id); 2191 if (c == NULL) { 2192 log("channel_open: %d: bad id", id); 2193 return; 2194 } 2195 debug("send channel open %d", id); 2196 packet_start(SSH2_MSG_CHANNEL_OPEN); 2197 packet_put_cstring(c->ctype); 2198 packet_put_int(c->self); 2199 packet_put_int(c->local_window); 2200 packet_put_int(c->local_maxpacket); 2201} 2202void 2203channel_open(int id) 2204{ 2205 /* XXX REMOVE ME */ 2206 channel_start_open(id); 2207 packet_send(); 2208} 2209void 2210channel_request(int id, char *service, int wantconfirm) 2211{ 2212 channel_request_start(id, service, wantconfirm); 2213 packet_send(); 2214 debug("channel request %d: %s", id, service) ; 2215} 2216void 2217channel_request_start(int id, char *service, int wantconfirm) 2218{ 2219 Channel *c = channel_lookup(id); 2220 if (c == NULL) { 2221 log("channel_request: %d: bad id", id); 2222 return; 2223 } 2224 packet_start(SSH2_MSG_CHANNEL_REQUEST); 2225 packet_put_int(c->remote_id); 2226 packet_put_cstring(service); 2227 packet_put_char(wantconfirm); 2228} 2229void 2230channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg) 2231{ 2232 Channel *c = channel_lookup(id); 2233 if (c == NULL) { 2234 log("channel_register_callback: %d: bad id", id); 2235 return; 2236 } 2237 c->cb_event = mtype; 2238 c->cb_fn = fn; 2239 c->cb_arg = arg; 2240} 2241void 2242channel_register_cleanup(int id, channel_callback_fn *fn) 2243{ 2244 Channel *c = channel_lookup(id); 2245 if (c == NULL) { 2246 log("channel_register_cleanup: %d: bad id", id); 2247 return; 2248 } 2249 c->dettach_user = fn; 2250} 2251void 2252channel_cancel_cleanup(int id) 2253{ 2254 Channel *c = channel_lookup(id); 2255 if (c == NULL) { 2256 log("channel_cancel_cleanup: %d: bad id", id); 2257 return; 2258 } 2259 c->dettach_user = NULL; 2260} 2261 2262void 2263channel_set_fds(int id, int rfd, int wfd, int efd, int extusage) 2264{ 2265 Channel *c = channel_lookup(id); 2266 if (c == NULL || c->type != SSH_CHANNEL_LARVAL) 2267 fatal("channel_activate for non-larval channel %d.", id); 2268 2269 channel_register_fds(c, rfd, wfd, efd, extusage); 2270 c->type = SSH_CHANNEL_OPEN; 2271 /* XXX window size? */ 2272 c->local_window = c->local_window_max = c->local_maxpacket/2; 2273 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); 2274 packet_put_int(c->remote_id); 2275 packet_put_int(c->local_window); 2276 packet_send(); 2277} 2278