openssh/channels.c

   1 /* $OpenBSD: channels.c,v 1.296 2009/05/25 06:48:00 andreas Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * This file contains functions for generic socket connection forwarding.
   7  * There is also code for initiating connection forwarding for X11 connections,
   8  * arbitrary tcp/ip connections, and the authentication agent connection.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * SSH2 support added by Markus Friedl.
  17  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
  18  * Copyright (c) 1999 Dug Song.  All rights reserved.
  19  * Copyright (c) 1999 Theo de Raadt.  All rights reserved.
  20  *
  21  * Redistribution and use in source and binary forms, with or without
  22  * modification, are permitted provided that the following conditions
  23  * are met:
  24  * 1. Redistributions of source code must retain the above copyright
  25  *    notice, this list of conditions and the following disclaimer.
  26  * 2. Redistributions in binary form must reproduce the above copyright
  27  *    notice, this list of conditions and the following disclaimer in the
  28  *    documentation and/or other materials provided with the distribution.
  29  *
  30  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  31  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  32  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  33  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  34  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  35  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  36  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  37  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  38  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  39  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  40  */
  41
  42 #include "includes.h"
  43
  44 #include <sys/types.h>
  45 #include <sys/ioctl.h>
  46 #include <sys/un.h>
  47 #include <sys/socket.h>
  48 #ifdef HAVE_SYS_TIME_H
  49 # include <sys/time.h>
  50 #endif
  51
  52 #include <netinet/in.h>
  53 #include <arpa/inet.h>
  54
  55 #include <errno.h>
  56 #include <netdb.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 "openbsd-compat/sys-queue.h"
  65 #include "xmalloc.h"
  66 #include "ssh.h"
  67 #include "ssh1.h"
  68 #include "ssh2.h"
  69 #include "packet.h"
  70 #include "log.h"
  71 #include "misc.h"
  72 #include "buffer.h"
  73 #include "channels.h"
  74 #include "compat.h"
  75 #include "canohost.h"
  76 #include "key.h"
  77 #include "authfd.h"
  78 #include "pathnames.h"
  79
  80 /* -- channel core */
  81
  82 /*
  83  * Pointer to an array containing all allocated channels.  The array is
  84  * dynamically extended as needed.
  85  */
  86 static Channel **channels = NULL;
  87
  88 /*
  89  * Size of the channel array.  All slots of the array must always be
  90  * initialized (at least the type field); unused slots set to NULL
  91  */
  92 static u_int channels_alloc = 0;
  93
  94 /*
  95  * Maximum file descriptor value used in any of the channels.  This is
  96  * updated in channel_new.
  97  */
  98 static int channel_max_fd = 0;
  99
 100
 101 /* -- tcp forwarding */
 102
 103 /*
 104  * Data structure for storing which hosts are permitted for forward requests.
 105  * The local sides of any remote forwards are stored in this array to prevent
 106  * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
 107  * network (which might be behind a firewall).
 108  */
 109 typedef struct {
 110         char *host_to_connect;          /* Connect to 'host'. */
 111         u_short port_to_connect;        /* Connect to 'port'. */
 112         u_short listen_port;            /* Remote side should listen port number. */
 113 } ForwardPermission;
 114
 115 /* List of all permitted host/port pairs to connect by the user. */
 116 static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
 117
 118 /* List of all permitted host/port pairs to connect by the admin. */
 119 static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
 120
 121 /* Number of permitted host/port pairs in the array permitted by the user. */
 122 static int num_permitted_opens = 0;
 123
 124 /* Number of permitted host/port pair in the array permitted by the admin. */
 125 static int num_adm_permitted_opens = 0;
 126
 127 /*
 128  * If this is true, all opens are permitted.  This is the case on the server
 129  * on which we have to trust the client anyway, and the user could do
 130  * anything after logging in anyway.
 131  */
 132 static int all_opens_permitted = 0;
 133
 134
 135 /* -- X11 forwarding */
 136
 137 /* Maximum number of fake X11 displays to try. */
 138 #define MAX_DISPLAYS  1000
 139
 140 /* Saved X11 local (client) display. */
 141 static char *x11_saved_display = NULL;
 142
 143 /* Saved X11 authentication protocol name. */
 144 static char *x11_saved_proto = NULL;
 145
 146 /* Saved X11 authentication data.  This is the real data. */
 147 static char *x11_saved_data = NULL;
 148 static u_int x11_saved_data_len = 0;
 149
 150 /*
 151  * Fake X11 authentication data.  This is what the server will be sending us;
 152  * we should replace any occurrences of this by the real data.
 153  */
 154 static u_char *x11_fake_data = NULL;
 155 static u_int x11_fake_data_len;
 156
 157
 158 /* -- agent forwarding */
 159
 160 #define NUM_SOCKS       10
 161
 162 /* AF_UNSPEC or AF_INET or AF_INET6 */
 163 static int IPv4or6 = AF_UNSPEC;
 164
 165 /* helper */
 166 static void port_open_helper(Channel *c, char *rtype);
 167
 168 /* non-blocking connect helpers */
 169 static int connect_next(struct channel_connect *);
 170 static void channel_connect_ctx_free(struct channel_connect *);
 171
 172
 173 static int hpn_disabled = 0;
 174 static int hpn_buffer_size = 2 * 1024 * 1024;
 175
 176 /* -- channel core */
 177
 178
 179
 180 Channel *
 181 channel_by_id(int id)
 182 {
 183         Channel *c;
 184
 185         if (id < 0 || (u_int)id >= channels_alloc) {
 186                 logit("channel_by_id: %d: bad id", id);
 187                 return NULL;
 188         }
 189         c = channels[id];
 190         if (c == NULL) {
 191                 logit("channel_by_id: %d: bad id: channel free", id);
 192                 return NULL;
 193         }
 194         return c;
 195 }
 196
 197 /*
 198  * Returns the channel if it is allowed to receive protocol messages.
 199  * Private channels, like listening sockets, may not receive messages.
 200  */
 201 Channel *
 202 channel_lookup(int id)
 203 {
 204         Channel *c;
 205
 206         if ((c = channel_by_id(id)) == NULL)
 207                 return (NULL);
 208
 209         switch (c->type) {
 210         case SSH_CHANNEL_X11_OPEN:
 211         case SSH_CHANNEL_LARVAL:
 212         case SSH_CHANNEL_CONNECTING:
 213         case SSH_CHANNEL_DYNAMIC:
 214         case SSH_CHANNEL_OPENING:
 215         case SSH_CHANNEL_OPEN:
 216         case SSH_CHANNEL_INPUT_DRAINING:
 217         case SSH_CHANNEL_OUTPUT_DRAINING:
 218                 return (c);
 219         }
 220         logit("Non-public channel %d, type %d.", id, c->type);
 221         return (NULL);
 222 }
 223
 224 /*
 225  * Register filedescriptors for a channel, used when allocating a channel or
 226  * when the channel consumer/producer is ready, e.g. shell exec'd
 227  */
 228 static void
 229 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
 230     int extusage, int nonblock, int is_tty)
 231 {
 232         /* Update the maximum file descriptor value. */
 233         channel_max_fd = MAX(channel_max_fd, rfd);
 234         channel_max_fd = MAX(channel_max_fd, wfd);
 235         channel_max_fd = MAX(channel_max_fd, efd);
 236
 237         /* XXX set close-on-exec -markus */
 238
 239         c->rfd = rfd;
 240         c->wfd = wfd;
 241         c->sock = (rfd == wfd) ? rfd : -1;
 242         c->ctl_fd = -1; /* XXX: set elsewhere */
 243         c->efd = efd;
 244         c->extended_usage = extusage;
 245
 246         if ((c->isatty = is_tty) != 0)
 247                 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
 248         c->wfd_isatty = is_tty || isatty(c->wfd);
 249
 250         /* enable nonblocking mode */
 251         if (nonblock) {
 252                 if (rfd != -1)
 253                         set_nonblock(rfd);
 254                 if (wfd != -1)
 255                         set_nonblock(wfd);
 256                 if (efd != -1)
 257                         set_nonblock(efd);
 258         }
 259 }
 260
 261 /*
 262  * Allocate a new channel object and set its type and socket. This will cause
 263  * remote_name to be freed.
 264  */
 265 Channel *
 266 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
 267     u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
 268 {
 269         int found;
 270         u_int i;
 271         Channel *c;
 272
 273         /* Do initial allocation if this is the first call. */
 274         if (channels_alloc == 0) {
 275                 channels_alloc = 10;
 276                 channels = xcalloc(channels_alloc, sizeof(Channel *));
 277                 for (i = 0; i < channels_alloc; i++)
 278                         channels[i] = NULL;
 279         }
 280         /* Try to find a free slot where to put the new channel. */
 281         for (found = -1, i = 0; i < channels_alloc; i++)
 282                 if (channels[i] == NULL) {
 283                         /* Found a free slot. */
 284                         found = (int)i;
 285                         break;
 286                 }
 287         if (found < 0) {
 288                 /* There are no free slots.  Take last+1 slot and expand the array.  */
 289                 found = channels_alloc;
 290                 if (channels_alloc > 10000)
 291                         fatal("channel_new: internal error: channels_alloc %d "
 292                             "too big.", channels_alloc);
 293                 channels = xrealloc(channels, channels_alloc + 10,
 294                     sizeof(Channel *));
 295                 channels_alloc += 10;
 296                 debug2("channel: expanding %d", channels_alloc);
 297                 for (i = found; i < channels_alloc; i++)
 298                         channels[i] = NULL;
 299         }
 300         /* Initialize and return new channel. */
 301         c = channels[found] = xcalloc(1, sizeof(Channel));
 302         buffer_init(&c->input);
 303         buffer_init(&c->output);
 304         buffer_init(&c->extended);
 305         c->path = NULL;
 306         c->ostate = CHAN_OUTPUT_OPEN;
 307         c->istate = CHAN_INPUT_OPEN;
 308         c->flags = 0;
 309         channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
 310         c->self = found;
 311         c->type = type;
 312         c->ctype = ctype;
 313         c->local_window = window;
 314         c->local_window_max = window;
 315         c->local_consumed = 0;
 316         c->local_maxpacket = maxpack;
 317         c->dynamic_window = 0;
 318         c->remote_id = -1;
 319         c->remote_name = xstrdup(remote_name);
 320         c->remote_window = 0;
 321         c->remote_maxpacket = 0;
 322         c->force_drain = 0;
 323         c->single_connection = 0;
 324         c->detach_user = NULL;
 325         c->detach_close = 0;
 326         c->open_confirm = NULL;
 327         c->open_confirm_ctx = NULL;
 328         c->input_filter = NULL;
 329         c->output_filter = NULL;
 330         c->filter_ctx = NULL;
 331         c->filter_cleanup = NULL;
 332         TAILQ_INIT(&c->status_confirms);
 333         debug("channel %d: new [%s]", found, remote_name);
 334         return c;
 335 }
 336
 337 static int
 338 channel_find_maxfd(void)
 339 {
 340         u_int i;
 341         int max = 0;
 342         Channel *c;
 343
 344         for (i = 0; i < channels_alloc; i++) {
 345                 c = channels[i];
 346                 if (c != NULL) {
 347                         max = MAX(max, c->rfd);
 348                         max = MAX(max, c->wfd);
 349                         max = MAX(max, c->efd);
 350                 }
 351         }
 352         return max;
 353 }
 354
 355 int
 356 channel_close_fd(int *fdp)
 357 {
 358         int ret = 0, fd = *fdp;
 359
 360         if (fd != -1) {
 361                 ret = close(fd);
 362                 *fdp = -1;
 363                 if (fd == channel_max_fd)
 364                         channel_max_fd = channel_find_maxfd();
 365         }
 366         return ret;
 367 }
 368
 369 /* Close all channel fd/socket. */
 370 static void
 371 channel_close_fds(Channel *c)
 372 {
 373         debug3("channel %d: close_fds r %d w %d e %d c %d",
 374             c->self, c->rfd, c->wfd, c->efd, c->ctl_fd);
 375
 376         channel_close_fd(&c->sock);
 377         channel_close_fd(&c->ctl_fd);
 378         channel_close_fd(&c->rfd);
 379         channel_close_fd(&c->wfd);
 380         channel_close_fd(&c->efd);
 381 }
 382
 383 /* Free the channel and close its fd/socket. */
 384 void
 385 channel_free(Channel *c)
 386 {
 387         char *s;
 388         u_int i, n;
 389         struct channel_confirm *cc;
 390
 391         for (n = 0, i = 0; i < channels_alloc; i++)
 392                 if (channels[i])
 393                         n++;
 394         debug("channel %d: free: %s, nchannels %u", c->self,
 395             c->remote_name ? c->remote_name : "???", n);
 396
 397         s = channel_open_message();
 398         debug3("channel %d: status: %s", c->self, s);
 399         xfree(s);
 400
 401         if (c->sock != -1)
 402                 shutdown(c->sock, SHUT_RDWR);
 403         if (c->ctl_fd != -1)
 404                 shutdown(c->ctl_fd, SHUT_RDWR);
 405         channel_close_fds(c);
 406         buffer_free(&c->input);
 407         buffer_free(&c->output);
 408         buffer_free(&c->extended);
 409         if (c->remote_name) {
 410                 xfree(c->remote_name);
 411                 c->remote_name = NULL;
 412         }
 413         if (c->path) {
 414                 xfree(c->path);
 415                 c->path = NULL;
 416         }
 417         while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
 418                 if (cc->abandon_cb != NULL)
 419                         cc->abandon_cb(c, cc->ctx);
 420                 TAILQ_REMOVE(&c->status_confirms, cc, entry);
 421                 bzero(cc, sizeof(*cc));
 422                 xfree(cc);
 423         }
 424         if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
 425                 c->filter_cleanup(c->self, c->filter_ctx);
 426         channels[c->self] = NULL;
 427         xfree(c);
 428 }
 429
 430 void
 431 channel_free_all(void)
 432 {
 433         u_int i;
 434
 435         for (i = 0; i < channels_alloc; i++)
 436                 if (channels[i] != NULL)
 437                         channel_free(channels[i]);
 438 }
 439
 440 /*
 441  * Closes the sockets/fds of all channels.  This is used to close extra file
 442  * descriptors after a fork.
 443  */
 444 void
 445 channel_close_all(void)
 446 {
 447         u_int i;
 448
 449         for (i = 0; i < channels_alloc; i++)
 450                 if (channels[i] != NULL)
 451                         channel_close_fds(channels[i]);
 452 }
 453
 454 /*
 455  * Stop listening to channels.
 456  */
 457 void
 458 channel_stop_listening(void)
 459 {
 460         u_int i;
 461         Channel *c;
 462
 463         for (i = 0; i < channels_alloc; i++) {
 464                 c = channels[i];
 465                 if (c != NULL) {
 466                         switch (c->type) {
 467                         case SSH_CHANNEL_AUTH_SOCKET:
 468                         case SSH_CHANNEL_PORT_LISTENER:
 469                         case SSH_CHANNEL_RPORT_LISTENER:
 470                         case SSH_CHANNEL_X11_LISTENER:
 471                                 channel_close_fd(&c->sock);
 472                                 channel_free(c);
 473                                 break;
 474                         }
 475                 }
 476         }
 477 }
 478
 479 /*
 480  * Returns true if no channel has too much buffered data, and false if one or
 481  * more channel is overfull.
 482  */
 483 int
 484 channel_not_very_much_buffered_data(void)
 485 {
 486         u_int i;
 487         Channel *c;
 488
 489         for (i = 0; i < channels_alloc; i++) {
 490                 c = channels[i];
 491                 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
 492 #if 0
 493                         if (!compat20 &&
 494                             buffer_len(&c->input) > packet_get_maxsize()) {
 495                                 debug2("channel %d: big input buffer %d",
 496                                     c->self, buffer_len(&c->input));
 497                                 return 0;
 498                         }
 499 #endif
 500                         if (buffer_len(&c->output) > packet_get_maxsize()) {
 501                                 debug2("channel %d: big output buffer %u > %u",
 502                                     c->self, buffer_len(&c->output),
 503                                     packet_get_maxsize());
 504                                 return 0;
 505                         }
 506                 }
 507         }
 508         return 1;
 509 }
 510
 511 /* Returns true if any channel is still open. */
 512 int
 513 channel_still_open(void)
 514 {
 515         u_int i;
 516         Channel *c;
 517
 518         for (i = 0; i < channels_alloc; i++) {
 519                 c = channels[i];
 520                 if (c == NULL)
 521                         continue;
 522                 switch (c->type) {
 523                 case SSH_CHANNEL_X11_LISTENER:
 524                 case SSH_CHANNEL_PORT_LISTENER:
 525                 case SSH_CHANNEL_RPORT_LISTENER:
 526                 case SSH_CHANNEL_CLOSED:
 527                 case SSH_CHANNEL_AUTH_SOCKET:
 528                 case SSH_CHANNEL_DYNAMIC:
 529                 case SSH_CHANNEL_CONNECTING:
 530                 case SSH_CHANNEL_ZOMBIE:
 531                         continue;
 532                 case SSH_CHANNEL_LARVAL:
 533                         if (!compat20)
 534                                 fatal("cannot happen: SSH_CHANNEL_LARVAL");
 535                         continue;
 536                 case SSH_CHANNEL_OPENING:
 537                 case SSH_CHANNEL_OPEN:
 538                 case SSH_CHANNEL_X11_OPEN:
 539                         return 1;
 540                 case SSH_CHANNEL_INPUT_DRAINING:
 541                 case SSH_CHANNEL_OUTPUT_DRAINING:
 542                         if (!compat13)
 543                                 fatal("cannot happen: OUT_DRAIN");
 544                         return 1;
 545                 default:
 546                         fatal("channel_still_open: bad channel type %d", c->type);
 547                         /* NOTREACHED */
 548                 }
 549         }
 550         return 0;
 551 }
 552
 553 /* Returns the id of an open channel suitable for keepaliving */
 554 int
 555 channel_find_open(void)
 556 {
 557         u_int i;
 558         Channel *c;
 559
 560         for (i = 0; i < channels_alloc; i++) {
 561                 c = channels[i];
 562                 if (c == NULL || c->remote_id < 0)
 563                         continue;
 564                 switch (c->type) {
 565                 case SSH_CHANNEL_CLOSED:
 566                 case SSH_CHANNEL_DYNAMIC:
 567                 case SSH_CHANNEL_X11_LISTENER:
 568                 case SSH_CHANNEL_PORT_LISTENER:
 569                 case SSH_CHANNEL_RPORT_LISTENER:
 570                 case SSH_CHANNEL_OPENING:
 571                 case SSH_CHANNEL_CONNECTING:
 572                 case SSH_CHANNEL_ZOMBIE:
 573                         continue;
 574                 case SSH_CHANNEL_LARVAL:
 575                 case SSH_CHANNEL_AUTH_SOCKET:
 576                 case SSH_CHANNEL_OPEN:
 577                 case SSH_CHANNEL_X11_OPEN:
 578                         return i;
 579                 case SSH_CHANNEL_INPUT_DRAINING:
 580                 case SSH_CHANNEL_OUTPUT_DRAINING:
 581                         if (!compat13)
 582                                 fatal("cannot happen: OUT_DRAIN");
 583                         return i;
 584                 default:
 585                         fatal("channel_find_open: bad channel type %d", c->type);
 586                         /* NOTREACHED */
 587                 }
 588         }
 589         return -1;
 590 }
 591
 592
 593 /*
 594  * Returns a message describing the currently open forwarded connections,
 595  * suitable for sending to the client.  The message contains crlf pairs for
 596  * newlines.
 597  */
 598 char *
 599 channel_open_message(void)
 600 {
 601         Buffer buffer;
 602         Channel *c;
 603         char buf[1024], *cp;
 604         u_int i;
 605
 606         buffer_init(&buffer);
 607         snprintf(buf, sizeof buf, "The following connections are open:\r\n");
 608         buffer_append(&buffer, buf, strlen(buf));
 609         for (i = 0; i < channels_alloc; i++) {
 610                 c = channels[i];
 611                 if (c == NULL)
 612                         continue;
 613                 switch (c->type) {
 614                 case SSH_CHANNEL_X11_LISTENER:
 615                 case SSH_CHANNEL_PORT_LISTENER:
 616                 case SSH_CHANNEL_RPORT_LISTENER:
 617                 case SSH_CHANNEL_CLOSED:
 618                 case SSH_CHANNEL_AUTH_SOCKET:
 619                 case SSH_CHANNEL_ZOMBIE:
 620                         continue;
 621                 case SSH_CHANNEL_LARVAL:
 622                 case SSH_CHANNEL_OPENING:
 623                 case SSH_CHANNEL_CONNECTING:
 624                 case SSH_CHANNEL_DYNAMIC:
 625                 case SSH_CHANNEL_OPEN:
 626                 case SSH_CHANNEL_X11_OPEN:
 627                 case SSH_CHANNEL_INPUT_DRAINING:
 628                 case SSH_CHANNEL_OUTPUT_DRAINING:
 629                         snprintf(buf, sizeof buf,
 630                             "  #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n",
 631                             c->self, c->remote_name,
 632                             c->type, c->remote_id,
 633                             c->istate, buffer_len(&c->input),
 634                             c->ostate, buffer_len(&c->output),
 635                             c->rfd, c->wfd, c->ctl_fd);
 636                         buffer_append(&buffer, buf, strlen(buf));
 637                         continue;
 638                 default:
 639                         fatal("channel_open_message: bad channel type %d", c->type);
 640                         /* NOTREACHED */
 641                 }
 642         }
 643         buffer_append(&buffer, "\0", 1);
 644         cp = xstrdup(buffer_ptr(&buffer));
 645         buffer_free(&buffer);
 646         return cp;
 647 }
 648
 649 void
 650 channel_send_open(int id)
 651 {
 652         Channel *c = channel_lookup(id);
 653
 654         if (c == NULL) {
 655                 logit("channel_send_open: %d: bad id", id);
 656                 return;
 657         }
 658         debug2("channel %d: send open", id);
 659         packet_start(SSH2_MSG_CHANNEL_OPEN);
 660         packet_put_cstring(c->ctype);
 661         packet_put_int(c->self);
 662         packet_put_int(c->local_window);
 663         packet_put_int(c->local_maxpacket);
 664         packet_send();
 665 }
 666
 667 void
 668 channel_request_start(int id, char *service, int wantconfirm)
 669 {
 670         Channel *c = channel_lookup(id);
 671
 672         if (c == NULL) {
 673                 logit("channel_request_start: %d: unknown channel id", id);
 674                 return;
 675         }
 676         debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
 677         packet_start(SSH2_MSG_CHANNEL_REQUEST);
 678         packet_put_int(c->remote_id);
 679         packet_put_cstring(service);
 680         packet_put_char(wantconfirm);
 681 }
 682
 683 void
 684 channel_register_status_confirm(int id, channel_confirm_cb *cb,
 685     channel_confirm_abandon_cb *abandon_cb, void *ctx)
 686 {
 687         struct channel_confirm *cc;
 688         Channel *c;
 689
 690         if ((c = channel_lookup(id)) == NULL)
 691                 fatal("channel_register_expect: %d: bad id", id);
 692
 693         cc = xmalloc(sizeof(*cc));
 694         cc->cb = cb;
 695         cc->abandon_cb = abandon_cb;
 696         cc->ctx = ctx;
 697         TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
 698 }
 699
 700 void
 701 channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx)
 702 {
 703         Channel *c = channel_lookup(id);
 704
 705         if (c == NULL) {
 706                 logit("channel_register_open_confirm: %d: bad id", id);
 707                 return;
 708         }
 709         c->open_confirm = fn;
 710         c->open_confirm_ctx = ctx;
 711 }
 712
 713 void
 714 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
 715 {
 716         Channel *c = channel_by_id(id);
 717
 718         if (c == NULL) {
 719                 logit("channel_register_cleanup: %d: bad id", id);
 720                 return;
 721         }
 722         c->detach_user = fn;
 723         c->detach_close = do_close;
 724 }
 725
 726 void
 727 channel_cancel_cleanup(int id)
 728 {
 729         Channel *c = channel_by_id(id);
 730
 731         if (c == NULL) {
 732                 logit("channel_cancel_cleanup: %d: bad id", id);
 733                 return;
 734         }
 735         c->detach_user = NULL;
 736         c->detach_close = 0;
 737 }
 738
 739 void
 740 channel_register_filter(int id, channel_infilter_fn *ifn,
 741     channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
 742 {
 743         Channel *c = channel_lookup(id);
 744
 745         if (c == NULL) {
 746                 logit("channel_register_filter: %d: bad id", id);
 747                 return;
 748         }
 749         c->input_filter = ifn;
 750         c->output_filter = ofn;
 751         c->filter_ctx = ctx;
 752         c->filter_cleanup = cfn;
 753 }
 754
 755 void
 756 channel_set_fds(int id, int rfd, int wfd, int efd,
 757     int extusage, int nonblock, int is_tty, u_int window_max)
 758 {
 759         Channel *c = channel_lookup(id);
 760
 761         if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
 762                 fatal("channel_activate for non-larval channel %d.", id);
 763         channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
 764         c->type = SSH_CHANNEL_OPEN;
 765         c->local_window = c->local_window_max = window_max;
 766         packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
 767         packet_put_int(c->remote_id);
 768         packet_put_int(c->local_window);
 769         packet_send();
 770 }
 771
 772 /*
 773  * 'channel_pre*' are called just before select() to add any bits relevant to
 774  * channels in the select bitmasks.
 775  */
 776 /*
 777  * 'channel_post*': perform any appropriate operations for channels which
 778  * have events pending.
 779  */
 780 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
 781 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
 782 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
 783
 784 /* ARGSUSED */
 785 static void
 786 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
 787 {
 788         FD_SET(c->sock, readset);
 789 }
 790
 791 /* ARGSUSED */
 792 static void
 793 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
 794 {
 795         debug3("channel %d: waiting for connection", c->self);
 796         FD_SET(c->sock, writeset);
 797 }
 798
 799 static void
 800 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
 801 {
 802         if (buffer_len(&c->input) < packet_get_maxsize())
 803                 FD_SET(c->sock, readset);
 804         if (buffer_len(&c->output) > 0)
 805                 FD_SET(c->sock, writeset);
 806 }
 807
 808 int channel_tcpwinsz () {
 809         u_int32_t tcpwinsz = 0;
 810         socklen_t optsz = sizeof(tcpwinsz);
 811         int ret = -1;
 812
 813         /* if we aren't on a socket return 128KB*/
 814         if(!packet_connection_is_on_socket())
 815             return(128*1024);
 816         ret = getsockopt(packet_get_connection_in(),
 817                          SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz);
 818         /* return no more than 64MB */
 819         if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN)
 820             tcpwinsz = BUFFER_MAX_LEN_HPN;
 821         return(tcpwinsz);
 822 }
 823
 824 static void
 825 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
 826 {
 827         u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
 828
 829         /* check buffer limits */
 830         if ((!c->tcpwinsz) || (c->dynamic_window > 0))
 831             c->tcpwinsz = channel_tcpwinsz();
 832
 833         limit = MIN(limit, 2 * c->tcpwinsz);
 834
 835         if (c->istate == CHAN_INPUT_OPEN &&
 836             limit > 0 &&
 837             buffer_len(&c->input) < limit &&
 838             buffer_check_alloc(&c->input, CHAN_RBUF))
 839                 FD_SET(c->rfd, readset);
 840         if (c->ostate == CHAN_OUTPUT_OPEN ||
 841             c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
 842                 if (buffer_len(&c->output) > 0) {
 843                         FD_SET(c->wfd, writeset);
 844                 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
 845                         if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
 846                                 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
 847                                     c->self, c->efd, buffer_len(&c->extended));
 848                         else
 849                                 chan_obuf_empty(c);
 850                 }
 851         }
 852         /** XXX check close conditions, too */
 853         if (compat20 && c->efd != -1 &&
 854             !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
 855                 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
 856                     buffer_len(&c->extended) > 0)
 857                         FD_SET(c->efd, writeset);
 858                 else if (!(c->flags & CHAN_EOF_SENT) &&
 859                     c->extended_usage == CHAN_EXTENDED_READ &&
 860                     buffer_len(&c->extended) < c->remote_window)
 861                         FD_SET(c->efd, readset);
 862         }
 863         /* XXX: What about efd? races? */
 864         if (compat20 && c->ctl_fd != -1 &&
 865             c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN)
 866                 FD_SET(c->ctl_fd, readset);
 867 }
 868
 869 /* ARGSUSED */
 870 static void
 871 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
 872 {
 873         if (buffer_len(&c->input) == 0) {
 874                 packet_start(SSH_MSG_CHANNEL_CLOSE);
 875                 packet_put_int(c->remote_id);
 876                 packet_send();
 877                 c->type = SSH_CHANNEL_CLOSED;
 878                 debug2("channel %d: closing after input drain.", c->self);
 879         }
 880 }
 881
 882 /* ARGSUSED */
 883 static void
 884 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
 885 {
 886         if (buffer_len(&c->output) == 0)
 887                 chan_mark_dead(c);
 888         else
 889                 FD_SET(c->sock, writeset);
 890 }
 891
 892 /*
 893  * This is a special state for X11 authentication spoofing.  An opened X11
 894  * connection (when authentication spoofing is being done) remains in this
 895  * state until the first packet has been completely read.  The authentication
 896  * data in that packet is then substituted by the real data if it matches the
 897  * fake data, and the channel is put into normal mode.
 898  * XXX All this happens at the client side.
 899  * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
 900  */
 901 static int
 902 x11_open_helper(Buffer *b)
 903 {
 904         u_char *ucp;
 905         u_int proto_len, data_len;
 906
 907         /* Check if the fixed size part of the packet is in buffer. */
 908         if (buffer_len(b) < 12)
 909                 return 0;
 910
 911         /* Parse the lengths of variable-length fields. */
 912         ucp = buffer_ptr(b);
 913         if (ucp[0] == 0x42) {   /* Byte order MSB first. */
 914                 proto_len = 256 * ucp[6] + ucp[7];
 915                 data_len = 256 * ucp[8] + ucp[9];
 916         } else if (ucp[0] == 0x6c) {    /* Byte order LSB first. */
 917                 proto_len = ucp[6] + 256 * ucp[7];
 918                 data_len = ucp[8] + 256 * ucp[9];
 919         } else {
 920                 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
 921                     ucp[0]);
 922                 return -1;
 923         }
 924
 925         /* Check if the whole packet is in buffer. */
 926         if (buffer_len(b) <
 927             12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
 928                 return 0;
 929
 930         /* Check if authentication protocol matches. */
 931         if (proto_len != strlen(x11_saved_proto) ||
 932             memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
 933                 debug2("X11 connection uses different authentication protocol.");
 934                 return -1;
 935         }
 936         /* Check if authentication data matches our fake data. */
 937         if (data_len != x11_fake_data_len ||
 938             memcmp(ucp + 12 + ((proto_len + 3) & ~3),
 939                 x11_fake_data, x11_fake_data_len) != 0) {
 940                 debug2("X11 auth data does not match fake data.");
 941                 return -1;
 942         }
 943         /* Check fake data length */
 944         if (x11_fake_data_len != x11_saved_data_len) {
 945                 error("X11 fake_data_len %d != saved_data_len %d",
 946                     x11_fake_data_len, x11_saved_data_len);
 947                 return -1;
 948         }
 949         /*
 950          * Received authentication protocol and data match
 951          * our fake data. Substitute the fake data with real
 952          * data.
 953          */
 954         memcpy(ucp + 12 + ((proto_len + 3) & ~3),
 955             x11_saved_data, x11_saved_data_len);
 956         return 1;
 957 }
 958
 959 static void
 960 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
 961 {
 962         int ret = x11_open_helper(&c->output);
 963
 964         if (ret == 1) {
 965                 /* Start normal processing for the channel. */
 966                 c->type = SSH_CHANNEL_OPEN;
 967                 channel_pre_open_13(c, readset, writeset);
 968         } else if (ret == -1) {
 969                 /*
 970                  * We have received an X11 connection that has bad
 971                  * authentication information.
 972                  */
 973                 logit("X11 connection rejected because of wrong authentication.");
 974                 buffer_clear(&c->input);
 975                 buffer_clear(&c->output);
 976                 channel_close_fd(&c->sock);
 977                 c->sock = -1;
 978                 c->type = SSH_CHANNEL_CLOSED;
 979                 packet_start(SSH_MSG_CHANNEL_CLOSE);
 980                 packet_put_int(c->remote_id);
 981                 packet_send();
 982         }
 983 }
 984
 985 static void
 986 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
 987 {
 988         int ret = x11_open_helper(&c->output);
 989
 990         /* c->force_drain = 1; */
 991
 992         if (ret == 1) {
 993                 c->type = SSH_CHANNEL_OPEN;
 994                 channel_pre_open(c, readset, writeset);
 995         } else if (ret == -1) {
 996                 logit("X11 connection rejected because of wrong authentication.");
 997                 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
 998                 chan_read_failed(c);
 999                 buffer_clear(&c->input);
1000                 chan_ibuf_empty(c);
1001                 buffer_clear(&c->output);
1002                 /* for proto v1, the peer will send an IEOF */
1003                 if (compat20)
1004                         chan_write_failed(c);
1005                 else
1006                         c->type = SSH_CHANNEL_OPEN;
1007                 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
1008         }
1009 }
1010
1011 /* try to decode a socks4 header */
1012 /* ARGSUSED */
1013 static int
1014 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1015 {
1016         char *p, *host;
1017         u_int len, have, i, found, need;
1018         char username[256];
1019         struct {
1020                 u_int8_t version;
1021                 u_int8_t command;
1022                 u_int16_t dest_port;
1023                 struct in_addr dest_addr;
1024         } s4_req, s4_rsp;
1025
1026         debug2("channel %d: decode socks4", c->self);
1027
1028         have = buffer_len(&c->input);
1029         len = sizeof(s4_req);
1030         if (have < len)
1031                 return 0;
1032         p = buffer_ptr(&c->input);
1033
1034         need = 1;
1035         /* SOCKS4A uses an invalid IP address 0.0.0.x */
1036         if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1037                 debug2("channel %d: socks4a request", c->self);
1038                 /* ... and needs an extra string (the hostname) */
1039                 need = 2;
1040         }
1041         /* Check for terminating NUL on the string(s) */
1042         for (found = 0, i = len; i < have; i++) {
1043                 if (p[i] == '\0') {
1044                         found++;
1045                         if (found == need)
1046                                 break;
1047                 }
1048                 if (i > 1024) {
1049                         /* the peer is probably sending garbage */
1050                         debug("channel %d: decode socks4: too long",
1051                             c->self);
1052                         return -1;
1053                 }
1054         }
1055         if (found < need)
1056                 return 0;
1057         buffer_get(&c->input, (char *)&s4_req.version, 1);
1058         buffer_get(&c->input, (char *)&s4_req.command, 1);
1059         buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1060         buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1061         have = buffer_len(&c->input);
1062         p = buffer_ptr(&c->input);
1063         len = strlen(p);
1064         debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1065         len++;                                  /* trailing '\0' */
1066         if (len > have)
1067                 fatal("channel %d: decode socks4: len %d > have %d",
1068                     c->self, len, have);
1069         strlcpy(username, p, sizeof(username));
1070         buffer_consume(&c->input, len);
1071
1072         if (c->path != NULL) {
1073                 xfree(c->path);
1074                 c->path = NULL;
1075         }
1076         if (need == 1) {                        /* SOCKS4: one string */
1077                 host = inet_ntoa(s4_req.dest_addr);
1078                 c->path = xstrdup(host);
1079         } else {                                /* SOCKS4A: two strings */
1080                 have = buffer_len(&c->input);
1081                 p = buffer_ptr(&c->input);
1082                 len = strlen(p);
1083                 debug2("channel %d: decode socks4a: host %s/%d",
1084                     c->self, p, len);
1085                 len++;                          /* trailing '\0' */
1086                 if (len > have)
1087                         fatal("channel %d: decode socks4a: len %d > have %d",
1088                             c->self, len, have);
1089                 if (len > NI_MAXHOST) {
1090                         error("channel %d: hostname \"%.100s\" too long",
1091                             c->self, p);
1092                         return -1;
1093                 }
1094                 c->path = xstrdup(p);
1095                 buffer_consume(&c->input, len);
1096         }
1097         c->host_port = ntohs(s4_req.dest_port);
1098
1099         debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1100             c->self, c->path, c->host_port, s4_req.command);
1101
1102         if (s4_req.command != 1) {
1103                 debug("channel %d: cannot handle: %s cn %d",
1104                     c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1105                 return -1;
1106         }
1107         s4_rsp.version = 0;                     /* vn: 0 for reply */
1108         s4_rsp.command = 90;                    /* cd: req granted */
1109         s4_rsp.dest_port = 0;                   /* ignored */
1110         s4_rsp.dest_addr.s_addr = INADDR_ANY;   /* ignored */
1111         buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1112         return 1;
1113 }
1114
1115 /* try to decode a socks5 header */
1116 #define SSH_SOCKS5_AUTHDONE     0x1000
1117 #define SSH_SOCKS5_NOAUTH       0x00
1118 #define SSH_SOCKS5_IPV4         0x01
1119 #define SSH_SOCKS5_DOMAIN       0x03
1120 #define SSH_SOCKS5_IPV6         0x04
1121 #define SSH_SOCKS5_CONNECT      0x01
1122 #define SSH_SOCKS5_SUCCESS      0x00
1123
1124 /* ARGSUSED */
1125 static int
1126 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1127 {
1128         struct {
1129                 u_int8_t version;
1130                 u_int8_t command;
1131                 u_int8_t reserved;
1132                 u_int8_t atyp;
1133         } s5_req, s5_rsp;
1134         u_int16_t dest_port;
1135         u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1136         u_int have, need, i, found, nmethods, addrlen, af;
1137
1138         debug2("channel %d: decode socks5", c->self);
1139         p = buffer_ptr(&c->input);
1140         if (p[0] != 0x05)
1141                 return -1;
1142         have = buffer_len(&c->input);
1143         if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1144                 /* format: ver | nmethods | methods */
1145                 if (have < 2)
1146                         return 0;
1147                 nmethods = p[1];
1148                 if (have < nmethods + 2)
1149                         return 0;
1150                 /* look for method: "NO AUTHENTICATION REQUIRED" */
1151                 for (found = 0, i = 2; i < nmethods + 2; i++) {
1152                         if (p[i] == SSH_SOCKS5_NOAUTH) {
1153                                 found = 1;
1154                                 break;
1155                         }
1156                 }
1157                 if (!found) {
1158                         debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1159                             c->self);
1160                         return -1;
1161                 }
1162                 buffer_consume(&c->input, nmethods + 2);
1163                 buffer_put_char(&c->output, 0x05);              /* version */
1164                 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1165                 FD_SET(c->sock, writeset);
1166                 c->flags |= SSH_SOCKS5_AUTHDONE;
1167                 debug2("channel %d: socks5 auth done", c->self);
1168                 return 0;                               /* need more */
1169         }
1170         debug2("channel %d: socks5 post auth", c->self);
1171         if (have < sizeof(s5_req)+1)
1172                 return 0;                       /* need more */
1173         memcpy(&s5_req, p, sizeof(s5_req));
1174         if (s5_req.version != 0x05 ||
1175             s5_req.command != SSH_SOCKS5_CONNECT ||
1176             s5_req.reserved != 0x00) {
1177                 debug2("channel %d: only socks5 connect supported", c->self);
1178                 return -1;
1179         }
1180         switch (s5_req.atyp){
1181         case SSH_SOCKS5_IPV4:
1182                 addrlen = 4;
1183                 af = AF_INET;
1184                 break;
1185         case SSH_SOCKS5_DOMAIN:
1186                 addrlen = p[sizeof(s5_req)];
1187                 af = -1;
1188                 break;
1189         case SSH_SOCKS5_IPV6:
1190                 addrlen = 16;
1191                 af = AF_INET6;
1192                 break;
1193         default:
1194                 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1195                 return -1;
1196         }
1197         need = sizeof(s5_req) + addrlen + 2;
1198         if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1199                 need++;
1200         if (have < need)
1201                 return 0;
1202         buffer_consume(&c->input, sizeof(s5_req));
1203         if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1204                 buffer_consume(&c->input, 1);    /* host string length */
1205         buffer_get(&c->input, (char *)&dest_addr, addrlen);
1206         buffer_get(&c->input, (char *)&dest_port, 2);
1207         dest_addr[addrlen] = '\0';
1208         if (c->path != NULL) {
1209                 xfree(c->path);
1210                 c->path = NULL;
1211         }
1212         if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1213                 if (addrlen >= NI_MAXHOST) {
1214                         error("channel %d: dynamic request: socks5 hostname "
1215                             "\"%.100s\" too long", c->self, dest_addr);
1216                         return -1;
1217                 }
1218                 c->path = xstrdup(dest_addr);
1219         } else {
1220                 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1221                         return -1;
1222                 c->path = xstrdup(ntop);
1223         }
1224         c->host_port = ntohs(dest_port);
1225
1226         debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1227             c->self, c->path, c->host_port, s5_req.command);
1228
1229         s5_rsp.version = 0x05;
1230         s5_rsp.command = SSH_SOCKS5_SUCCESS;
1231         s5_rsp.reserved = 0;                    /* ignored */
1232         s5_rsp.atyp = SSH_SOCKS5_IPV4;
1233         ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1234         dest_port = 0;                          /* ignored */
1235
1236         buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1237         buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1238         buffer_append(&c->output, &dest_port, sizeof(dest_port));
1239         return 1;
1240 }
1241
1242 /* dynamic port forwarding */
1243 static void
1244 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1245 {
1246         u_char *p;
1247         u_int have;
1248         int ret;
1249
1250         have = buffer_len(&c->input);
1251         c->delayed = 0;
1252         debug2("channel %d: pre_dynamic: have %d", c->self, have);
1253         /* buffer_dump(&c->input); */
1254         /* check if the fixed size part of the packet is in buffer. */
1255         if (have < 3) {
1256                 /* need more */
1257                 FD_SET(c->sock, readset);
1258                 return;
1259         }
1260         /* try to guess the protocol */
1261         p = buffer_ptr(&c->input);
1262         switch (p[0]) {
1263         case 0x04:
1264                 ret = channel_decode_socks4(c, readset, writeset);
1265                 break;
1266         case 0x05:
1267                 ret = channel_decode_socks5(c, readset, writeset);
1268                 break;
1269         default:
1270                 ret = -1;
1271                 break;
1272         }
1273         if (ret < 0) {
1274                 chan_mark_dead(c);
1275         } else if (ret == 0) {
1276                 debug2("channel %d: pre_dynamic: need more", c->self);
1277                 /* need more */
1278                 FD_SET(c->sock, readset);
1279         } else {
1280                 /* switch to the next state */
1281                 c->type = SSH_CHANNEL_OPENING;
1282                 port_open_helper(c, "direct-tcpip");
1283         }
1284 }
1285
1286 /* This is our fake X11 server socket. */
1287 /* ARGSUSED */
1288 static void
1289 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1290 {
1291         Channel *nc;
1292         struct sockaddr_storage addr;
1293         int newsock;
1294         socklen_t addrlen;
1295         char buf[16384], *remote_ipaddr;
1296         int remote_port;
1297
1298         if (FD_ISSET(c->sock, readset)) {
1299                 debug("X11 connection requested.");
1300                 addrlen = sizeof(addr);
1301                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1302                 if (c->single_connection) {
1303                         debug2("single_connection: closing X11 listener.");
1304                         channel_close_fd(&c->sock);
1305                         chan_mark_dead(c);
1306                 }
1307                 if (newsock < 0) {
1308                         error("accept: %.100s", strerror(errno));
1309                         return;
1310                 }
1311                 set_nodelay(newsock);
1312                 remote_ipaddr = get_peer_ipaddr(newsock);
1313                 remote_port = get_peer_port(newsock);
1314                 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1315                     remote_ipaddr, remote_port);
1316
1317                 nc = channel_new("accepted x11 socket",
1318                     SSH_CHANNEL_OPENING, newsock, newsock, -1,
1319                     c->local_window_max, c->local_maxpacket, 0, buf, 1);
1320                 if (compat20) {
1321                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1322                         packet_put_cstring("x11");
1323                         packet_put_int(nc->self);
1324                         packet_put_int(nc->local_window_max);
1325                         packet_put_int(nc->local_maxpacket);
1326                         /* originator ipaddr and port */
1327                         packet_put_cstring(remote_ipaddr);
1328                         if (datafellows & SSH_BUG_X11FWD) {
1329                                 debug2("ssh2 x11 bug compat mode");
1330                         } else {
1331                                 packet_put_int(remote_port);
1332                         }
1333                         packet_send();
1334                 } else {
1335                         packet_start(SSH_SMSG_X11_OPEN);
1336                         packet_put_int(nc->self);
1337                         if (packet_get_protocol_flags() &
1338                             SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1339                                 packet_put_cstring(buf);
1340                         packet_send();
1341                 }
1342                 xfree(remote_ipaddr);
1343         }
1344 }
1345
1346 static void
1347 port_open_helper(Channel *c, char *rtype)
1348 {
1349         int direct;
1350         char buf[1024];
1351         char *remote_ipaddr = get_peer_ipaddr(c->sock);
1352         int remote_port = get_peer_port(c->sock);
1353
1354         direct = (strcmp(rtype, "direct-tcpip") == 0);
1355
1356         snprintf(buf, sizeof buf,
1357             "%s: listening port %d for %.100s port %d, "
1358             "connect from %.200s port %d",
1359             rtype, c->listening_port, c->path, c->host_port,
1360             remote_ipaddr, remote_port);
1361
1362         xfree(c->remote_name);
1363         c->remote_name = xstrdup(buf);
1364
1365         if (compat20) {
1366                 packet_start(SSH2_MSG_CHANNEL_OPEN);
1367                 packet_put_cstring(rtype);
1368                 packet_put_int(c->self);
1369                 packet_put_int(c->local_window_max);
1370                 packet_put_int(c->local_maxpacket);
1371                 if (direct) {
1372                         /* target host, port */
1373                         packet_put_cstring(c->path);
1374                         packet_put_int(c->host_port);
1375                 } else {
1376                         /* listen address, port */
1377                         packet_put_cstring(c->path);
1378                         packet_put_int(c->listening_port);
1379                 }
1380                 /* originator host and port */
1381                 packet_put_cstring(remote_ipaddr);
1382                 packet_put_int((u_int)remote_port);
1383                 packet_send();
1384         } else {
1385                 packet_start(SSH_MSG_PORT_OPEN);
1386                 packet_put_int(c->self);
1387                 packet_put_cstring(c->path);
1388                 packet_put_int(c->host_port);
1389                 if (packet_get_protocol_flags() &
1390                     SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1391                         packet_put_cstring(c->remote_name);
1392                 packet_send();
1393         }
1394         xfree(remote_ipaddr);
1395 }
1396
1397 static void
1398 channel_set_reuseaddr(int fd)
1399 {
1400         int on = 1;
1401
1402         /*
1403          * Set socket options.
1404          * Allow local port reuse in TIME_WAIT.
1405          */
1406         if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1407                 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1408 }
1409
1410 /*
1411  * This socket is listening for connections to a forwarded TCP/IP port.
1412  */
1413 /* ARGSUSED */
1414 static void
1415 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1416 {
1417         Channel *nc;
1418         struct sockaddr_storage addr;
1419         int newsock, nextstate;
1420         socklen_t addrlen;
1421         char *rtype;
1422
1423         if (FD_ISSET(c->sock, readset)) {
1424                 debug("Connection to port %d forwarding "
1425                     "to %.100s port %d requested.",
1426                     c->listening_port, c->path, c->host_port);
1427
1428                 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1429                         nextstate = SSH_CHANNEL_OPENING;
1430                         rtype = "forwarded-tcpip";
1431                 } else {
1432                         if (c->host_port == 0) {
1433                                 nextstate = SSH_CHANNEL_DYNAMIC;
1434                                 rtype = "dynamic-tcpip";
1435                         } else {
1436                                 nextstate = SSH_CHANNEL_OPENING;
1437                                 rtype = "direct-tcpip";
1438                         }
1439                 }
1440
1441                 addrlen = sizeof(addr);
1442                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1443                 if (newsock < 0) {
1444                         error("accept: %.100s", strerror(errno));
1445                         return;
1446                 }
1447                 set_nodelay(newsock);
1448                 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1449                     c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1450                 nc->listening_port = c->listening_port;
1451                 nc->host_port = c->host_port;
1452                 if (c->path != NULL)
1453                         nc->path = xstrdup(c->path);
1454
1455                 if (nextstate == SSH_CHANNEL_DYNAMIC) {
1456                         /*
1457                          * do not call the channel_post handler until
1458                          * this flag has been reset by a pre-handler.
1459                          * otherwise the FD_ISSET calls might overflow
1460                          */
1461                         nc->delayed = 1;
1462                 } else {
1463                         port_open_helper(nc, rtype);
1464                 }
1465         }
1466 }
1467
1468 /*
1469  * This is the authentication agent socket listening for connections from
1470  * clients.
1471  */
1472 /* ARGSUSED */
1473 static void
1474 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1475 {
1476         Channel *nc;
1477         int newsock;
1478         struct sockaddr_storage addr;
1479         socklen_t addrlen;
1480
1481         if (FD_ISSET(c->sock, readset)) {
1482                 addrlen = sizeof(addr);
1483                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1484                 if (newsock < 0) {
1485                         error("accept from auth socket: %.100s", strerror(errno));
1486                         return;
1487                 }
1488                 nc = channel_new("accepted auth socket",
1489                     SSH_CHANNEL_OPENING, newsock, newsock, -1,
1490                     c->local_window_max, c->local_maxpacket,
1491                     0, "accepted auth socket", 1);
1492                 if (compat20) {
1493                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1494                         packet_put_cstring("auth-agent@openssh.com");
1495                         packet_put_int(nc->self);
1496                         packet_put_int(c->local_window_max);
1497                         packet_put_int(c->local_maxpacket);
1498                 } else {
1499                         packet_start(SSH_SMSG_AGENT_OPEN);
1500                         packet_put_int(nc->self);
1501                 }
1502                 packet_send();
1503         }
1504 }
1505
1506 /* ARGSUSED */
1507 static void
1508 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1509 {
1510         int err = 0, sock;
1511         socklen_t sz = sizeof(err);
1512
1513         if (FD_ISSET(c->sock, writeset)) {
1514                 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1515                         err = errno;
1516                         error("getsockopt SO_ERROR failed");
1517                 }
1518                 if (err == 0) {
1519                         debug("channel %d: connected to %s port %d",
1520                             c->self, c->connect_ctx.host, c->connect_ctx.port);
1521                         channel_connect_ctx_free(&c->connect_ctx);
1522                         c->type = SSH_CHANNEL_OPEN;
1523                         if (compat20) {
1524                                 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1525                                 packet_put_int(c->remote_id);
1526                                 packet_put_int(c->self);
1527                                 packet_put_int(c->local_window);
1528                                 packet_put_int(c->local_maxpacket);
1529                         } else {
1530                                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1531                                 packet_put_int(c->remote_id);
1532                                 packet_put_int(c->self);
1533                         }
1534                 } else {
1535                         debug("channel %d: connection failed: %s",
1536                             c->self, strerror(err));
1537                         /* Try next address, if any */
1538                         if ((sock = connect_next(&c->connect_ctx)) > 0) {
1539                                 close(c->sock);
1540                                 c->sock = c->rfd = c->wfd = sock;
1541                                 channel_max_fd = channel_find_maxfd();
1542                                 return;
1543                         }
1544                         /* Exhausted all addresses */
1545                         error("connect_to %.100s port %d: failed.",
1546                             c->connect_ctx.host, c->connect_ctx.port);
1547                         channel_connect_ctx_free(&c->connect_ctx);
1548                         if (compat20) {
1549                                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1550                                 packet_put_int(c->remote_id);
1551                                 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1552                                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1553                                         packet_put_cstring(strerror(err));
1554                                         packet_put_cstring("");
1555                                 }
1556                         } else {
1557                                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1558                                 packet_put_int(c->remote_id);
1559                         }
1560                         chan_mark_dead(c);
1561                 }
1562                 packet_send();
1563         }
1564 }
1565
1566 /* ARGSUSED */
1567 static int
1568 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1569 {
1570         char buf[CHAN_RBUF];
1571         int len, force;
1572
1573         force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1574         if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1575                 errno = 0;
1576                 len = read(c->rfd, buf, sizeof(buf));
1577                 if (len < 0 && (errno == EINTR ||
1578                     ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1579                         return 1;
1580 #ifndef PTY_ZEROREAD
1581                 if (len <= 0) {
1582 #else
1583                 if ((!c->isatty && len <= 0) ||
1584                     (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1585 #endif
1586                         debug2("channel %d: read<=0 rfd %d len %d",
1587                             c->self, c->rfd, len);
1588                         if (c->type != SSH_CHANNEL_OPEN) {
1589                                 debug2("channel %d: not open", c->self);
1590                                 chan_mark_dead(c);
1591                                 return -1;
1592                         } else if (compat13) {
1593                                 buffer_clear(&c->output);
1594                                 c->type = SSH_CHANNEL_INPUT_DRAINING;
1595                                 debug2("channel %d: input draining.", c->self);
1596                         } else {
1597                                 chan_read_failed(c);
1598                         }
1599                         return -1;
1600                 }
1601                 if (c->input_filter != NULL) {
1602                         if (c->input_filter(c, buf, len) == -1) {
1603                                 debug2("channel %d: filter stops", c->self);
1604                                 chan_read_failed(c);
1605                         }
1606                 } else if (c->datagram) {
1607                         buffer_put_string(&c->input, buf, len);
1608                 } else {
1609                         buffer_append(&c->input, buf, len);
1610                 }
1611         }
1612         return 1;
1613 }
1614
1615 /* ARGSUSED */
1616 static int
1617 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1618 {
1619         struct termios tio;
1620         u_char *data = NULL, *buf;
1621         u_int dlen;
1622         int len;
1623
1624         /* Send buffered output data to the socket. */
1625         if (c->wfd != -1 &&
1626             FD_ISSET(c->wfd, writeset) &&
1627             buffer_len(&c->output) > 0) {
1628                 if (c->output_filter != NULL) {
1629                         if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1630                                 debug2("channel %d: filter stops", c->self);
1631                                 if (c->type != SSH_CHANNEL_OPEN)
1632                                         chan_mark_dead(c);
1633                                 else
1634                                         chan_write_failed(c);
1635                                 return -1;
1636                         }
1637                 } else if (c->datagram) {
1638                         buf = data = buffer_get_string(&c->output, &dlen);
1639                 } else {
1640                         buf = data = buffer_ptr(&c->output);
1641                         dlen = buffer_len(&c->output);
1642                 }
1643
1644                 if (c->datagram) {
1645                         /* ignore truncated writes, datagrams might get lost */
1646                         c->local_consumed += dlen + 4;
1647                         len = write(c->wfd, buf, dlen);
1648                         xfree(data);
1649                         if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1650                             errno == EWOULDBLOCK))
1651                                 return 1;
1652                         if (len <= 0) {
1653                                 if (c->type != SSH_CHANNEL_OPEN)
1654                                         chan_mark_dead(c);
1655                                 else
1656                                         chan_write_failed(c);
1657                                 return -1;
1658                         }
1659                         return 1;
1660                 }
1661 #ifdef _AIX
1662                 /* XXX: Later AIX versions can't push as much data to tty */
1663                 if (compat20 && c->wfd_isatty)
1664                         dlen = MIN(dlen, 8*1024);
1665 #endif
1666
1667                 len = write(c->wfd, buf, dlen);
1668                 if (len < 0 &&
1669                     (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1670                         return 1;
1671                 if (len <= 0) {
1672                         if (c->type != SSH_CHANNEL_OPEN) {
1673                                 debug2("channel %d: not open", c->self);
1674                                 chan_mark_dead(c);
1675                                 return -1;
1676                         } else if (compat13) {
1677                                 buffer_clear(&c->output);
1678                                 debug2("channel %d: input draining.", c->self);
1679                                 c->type = SSH_CHANNEL_INPUT_DRAINING;
1680                         } else {
1681                                 chan_write_failed(c);
1682                         }
1683                         return -1;
1684                 }
1685 #ifndef BROKEN_TCGETATTR_ICANON
1686                 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1687                         if (tcgetattr(c->wfd, &tio) == 0 &&
1688                             !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1689                                 /*
1690                                  * Simulate echo to reduce the impact of
1691                                  * traffic analysis. We need to match the
1692                                  * size of a SSH2_MSG_CHANNEL_DATA message
1693                                  * (4 byte channel id + buf)
1694                                  */
1695                                 packet_send_ignore(4 + len);
1696                                 packet_send();
1697                         }
1698                 }
1699 #endif
1700                 buffer_consume(&c->output, len);
1701                 if (compat20 && len > 0) {
1702                         c->local_consumed += len;
1703                 }
1704         }
1705         return 1;
1706 }
1707
1708 static int
1709 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1710 {
1711         char buf[CHAN_RBUF];
1712         int len;
1713
1714 /** XXX handle drain efd, too */
1715         if (c->efd != -1) {
1716                 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1717                     FD_ISSET(c->efd, writeset) &&
1718                     buffer_len(&c->extended) > 0) {
1719                         len = write(c->efd, buffer_ptr(&c->extended),
1720                             buffer_len(&c->extended));
1721                         debug2("channel %d: written %d to efd %d",
1722                             c->self, len, c->efd);
1723                         if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1724                             errno == EWOULDBLOCK))
1725                                 return 1;
1726                         if (len <= 0) {
1727                                 debug2("channel %d: closing write-efd %d",
1728                                     c->self, c->efd);
1729                                 channel_close_fd(&c->efd);
1730                         } else {
1731                                 buffer_consume(&c->extended, len);
1732                                 c->local_consumed += len;
1733                         }
1734                 } else if (c->extended_usage == CHAN_EXTENDED_READ &&
1735                     (c->detach_close || FD_ISSET(c->efd, readset))) {
1736                         len = read(c->efd, buf, sizeof(buf));
1737                         debug2("channel %d: read %d from efd %d",
1738                             c->self, len, c->efd);
1739                         if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1740                             errno == EWOULDBLOCK) && !c->detach_close)))
1741                                 return 1;
1742                         if (len <= 0) {
1743                                 debug2("channel %d: closing read-efd %d",
1744                                     c->self, c->efd);
1745                                 channel_close_fd(&c->efd);
1746                         } else {
1747                                 buffer_append(&c->extended, buf, len);
1748                         }
1749                 }
1750         }
1751         return 1;
1752 }
1753
1754 /* ARGSUSED */
1755 static int
1756 channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset)
1757 {
1758         char buf[16];
1759         int len;
1760
1761         /* Monitor control fd to detect if the slave client exits */
1762         if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) {
1763                 len = read(c->ctl_fd, buf, sizeof(buf));
1764                 if (len < 0 &&
1765                     (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1766                         return 1;
1767                 if (len <= 0) {
1768                         debug2("channel %d: ctl read<=0", c->self);
1769                         if (c->type != SSH_CHANNEL_OPEN) {
1770                                 debug2("channel %d: not open", c->self);
1771                                 chan_mark_dead(c);
1772                                 return -1;
1773                         } else {
1774                                 chan_read_failed(c);
1775                                 chan_write_failed(c);
1776                         }
1777                         return -1;
1778                 } else
1779                         fatal("%s: unexpected data on ctl fd", __func__);
1780         }
1781         return 1;
1782 }
1783
1784 static int
1785 channel_check_window(Channel *c)
1786 {
1787         if (c->type == SSH_CHANNEL_OPEN &&
1788             !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1789             ((c->local_window_max - c->local_window >
1790             c->local_maxpacket*3) ||
1791             c->local_window < c->local_window_max/2) &&
1792             c->local_consumed > 0) {
1793                 u_int addition = 0;
1794                 /* adjust max window size if we are in a dynamic environment */
1795                 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1796                         /* grow the window somewhat aggressively to maintain pressure */
1797                         addition = 1.5*(c->tcpwinsz - c->local_window_max);
1798                         c->local_window_max += addition;
1799                 }
1800                 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1801                 packet_put_int(c->remote_id);
1802                 packet_put_int(c->local_consumed + addition);
1803                 packet_send();
1804                 debug2("channel %d: window %d sent adjust %d",
1805                     c->self, c->local_window,
1806                     c->local_consumed);
1807                 c->local_window += c->local_consumed + addition;
1808                 c->local_consumed = 0;
1809         }
1810         return 1;
1811 }
1812
1813 static void
1814 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1815 {
1816         if (c->delayed)
1817                 return;
1818         channel_handle_rfd(c, readset, writeset);
1819         channel_handle_wfd(c, readset, writeset);
1820         if (!compat20)
1821                 return;
1822         channel_handle_efd(c, readset, writeset);
1823         channel_handle_ctl(c, readset, writeset);
1824         channel_check_window(c);
1825 }
1826
1827 /* ARGSUSED */
1828 static void
1829 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1830 {
1831         int len;
1832
1833         /* Send buffered output data to the socket. */
1834         if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1835                 len = write(c->sock, buffer_ptr(&c->output),
1836                             buffer_len(&c->output));
1837                 if (len <= 0)
1838                         buffer_clear(&c->output);
1839                 else
1840                         buffer_consume(&c->output, len);
1841         }
1842 }
1843
1844 static void
1845 channel_handler_init_20(void)
1846 {
1847         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open;
1848         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open;
1849         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
1850         channel_pre[SSH_CHANNEL_RPORT_LISTENER] =       &channel_pre_listener;
1851         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
1852         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
1853         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
1854         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
1855
1856         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
1857         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
1858         channel_post[SSH_CHANNEL_RPORT_LISTENER] =      &channel_post_port_listener;
1859         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
1860         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
1861         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
1862         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
1863 }
1864
1865 static void
1866 channel_handler_init_13(void)
1867 {
1868         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open_13;
1869         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open_13;
1870         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
1871         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
1872         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
1873         channel_pre[SSH_CHANNEL_INPUT_DRAINING] =       &channel_pre_input_draining;
1874         channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] =      &channel_pre_output_draining;
1875         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
1876         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
1877
1878         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
1879         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
1880         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
1881         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
1882         channel_post[SSH_CHANNEL_OUTPUT_DRAINING] =     &channel_post_output_drain_13;
1883         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
1884         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
1885 }
1886
1887 static void
1888 channel_handler_init_15(void)
1889 {
1890         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open;
1891         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open;
1892         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
1893         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
1894         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
1895         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
1896         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
1897
1898         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
1899         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
1900         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
1901         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
1902         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
1903         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
1904 }
1905
1906 static void
1907 channel_handler_init(void)
1908 {
1909         int i;
1910
1911         for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
1912                 channel_pre[i] = NULL;
1913                 channel_post[i] = NULL;
1914         }
1915         if (compat20)
1916                 channel_handler_init_20();
1917         else if (compat13)
1918                 channel_handler_init_13();
1919         else
1920                 channel_handler_init_15();
1921 }
1922
1923 /* gc dead channels */
1924 static void
1925 channel_garbage_collect(Channel *c)
1926 {
1927         if (c == NULL)
1928                 return;
1929         if (c->detach_user != NULL) {
1930                 if (!chan_is_dead(c, c->detach_close))
1931                         return;
1932                 debug2("channel %d: gc: notify user", c->self);
1933                 c->detach_user(c->self, NULL);
1934                 /* if we still have a callback */
1935                 if (c->detach_user != NULL)
1936                         return;
1937                 debug2("channel %d: gc: user detached", c->self);
1938         }
1939         if (!chan_is_dead(c, 1))
1940                 return;
1941         debug2("channel %d: garbage collecting", c->self);
1942         channel_free(c);
1943 }
1944
1945 static void
1946 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
1947 {
1948         static int did_init = 0;
1949         u_int i;
1950         Channel *c;
1951
1952         if (!did_init) {
1953                 channel_handler_init();
1954                 did_init = 1;
1955         }
1956         for (i = 0; i < channels_alloc; i++) {
1957                 c = channels[i];
1958                 if (c == NULL)
1959                         continue;
1960                 if (ftab[c->type] != NULL)
1961                         (*ftab[c->type])(c, readset, writeset);
1962                 channel_garbage_collect(c);
1963         }
1964 }
1965
1966 /*
1967  * Allocate/update select bitmasks and add any bits relevant to channels in
1968  * select bitmasks.
1969  */
1970 void
1971 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
1972     u_int *nallocp, int rekeying)
1973 {
1974         u_int n, sz, nfdset;
1975
1976         n = MAX(*maxfdp, channel_max_fd);
1977
1978         nfdset = howmany(n+1, NFDBITS);
1979         /* Explicitly test here, because xrealloc isn't always called */
1980         if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
1981                 fatal("channel_prepare_select: max_fd (%d) is too large", n);
1982         sz = nfdset * sizeof(fd_mask);
1983
1984         /* perhaps check sz < nalloc/2 and shrink? */
1985         if (*readsetp == NULL || sz > *nallocp) {
1986                 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
1987                 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
1988                 *nallocp = sz;
1989         }
1990         *maxfdp = n;
1991         memset(*readsetp, 0, sz);
1992         memset(*writesetp, 0, sz);
1993
1994         if (!rekeying)
1995                 channel_handler(channel_pre, *readsetp, *writesetp);
1996 }
1997
1998 /*
1999  * After select, perform any appropriate operations for channels which have
2000  * events pending.
2001  */
2002 void
2003 channel_after_select(fd_set *readset, fd_set *writeset)
2004 {
2005         channel_handler(channel_post, readset, writeset);
2006 }
2007
2008
2009 /* If there is data to send to the connection, enqueue some of it now. */
2010 int
2011 channel_output_poll(void)
2012 {
2013         Channel *c;
2014         u_int i, len;
2015         int packet_length = 0;
2016
2017         for (i = 0; i < channels_alloc; i++) {
2018                 c = channels[i];
2019                 if (c == NULL)
2020                         continue;
2021
2022                 /*
2023                  * We are only interested in channels that can have buffered
2024                  * incoming data.
2025                  */
2026                 if (compat13) {
2027                         if (c->type != SSH_CHANNEL_OPEN &&
2028                             c->type != SSH_CHANNEL_INPUT_DRAINING)
2029                                 continue;
2030                 } else {
2031                         if (c->type != SSH_CHANNEL_OPEN)
2032                                 continue;
2033                 }
2034                 if (compat20 &&
2035                     (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2036                         /* XXX is this true? */
2037                         debug3("channel %d: will not send data after close", c->self);
2038                         continue;
2039                 }
2040
2041                 /* Get the amount of buffered data for this channel. */
2042                 if ((c->istate == CHAN_INPUT_OPEN ||
2043                     c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2044                     (len = buffer_len(&c->input)) > 0) {
2045                         if (c->datagram) {
2046                                 if (len > 0) {
2047                                         u_char *data;
2048                                         u_int dlen;
2049
2050                                         data = buffer_get_string(&c->input,
2051                                             &dlen);
2052                                         packet_start(SSH2_MSG_CHANNEL_DATA);
2053                                         packet_put_int(c->remote_id);
2054                                         packet_put_string(data, dlen);
2055                                         packet_length = packet_send();
2056                                         c->remote_window -= dlen + 4;
2057                                         xfree(data);
2058                                 }
2059                                 continue;
2060                         }
2061                         /*
2062                          * Send some data for the other side over the secure
2063                          * connection.
2064                          */
2065                         if (compat20) {
2066                                 if (len > c->remote_window)
2067                                         len = c->remote_window;
2068                                 if (len > c->remote_maxpacket)
2069                                         len = c->remote_maxpacket;
2070                         } else {
2071                                 if (packet_is_interactive()) {
2072                                         if (len > 1024)
2073                                                 len = 512;
2074                                 } else {
2075                                         /* Keep the packets at reasonable size. */
2076                                         if (len > packet_get_maxsize()/2)
2077                                                 len = packet_get_maxsize()/2;
2078                                 }
2079                         }
2080                         if (len > 0) {
2081                                 packet_start(compat20 ?
2082                                     SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2083                                 packet_put_int(c->remote_id);
2084                                 packet_put_string(buffer_ptr(&c->input), len);
2085                                 packet_length = packet_send();
2086                                 buffer_consume(&c->input, len);
2087                                 c->remote_window -= len;
2088                         }
2089                 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2090                         if (compat13)
2091                                 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2092                         /*
2093                          * input-buffer is empty and read-socket shutdown:
2094                          * tell peer, that we will not send more data: send IEOF.
2095                          * hack for extended data: delay EOF if EFD still in use.
2096                          */
2097                         if (CHANNEL_EFD_INPUT_ACTIVE(c))
2098                                 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2099                                     c->self, c->efd, buffer_len(&c->extended));
2100                         else
2101                                 chan_ibuf_empty(c);
2102                 }
2103                 /* Send extended data, i.e. stderr */
2104                 if (compat20 &&
2105                     !(c->flags & CHAN_EOF_SENT) &&
2106                     c->remote_window > 0 &&
2107                     (len = buffer_len(&c->extended)) > 0 &&
2108                     c->extended_usage == CHAN_EXTENDED_READ) {
2109                         debug2("channel %d: rwin %u elen %u euse %d",
2110                             c->self, c->remote_window, buffer_len(&c->extended),
2111                             c->extended_usage);
2112                         if (len > c->remote_window)
2113                                 len = c->remote_window;
2114                         if (len > c->remote_maxpacket)
2115                                 len = c->remote_maxpacket;
2116                         packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2117                         packet_put_int(c->remote_id);
2118                         packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2119                         packet_put_string(buffer_ptr(&c->extended), len);
2120                         packet_length = packet_send();
2121                         buffer_consume(&c->extended, len);
2122                         c->remote_window -= len;
2123                         debug2("channel %d: sent ext data %d", c->self, len);
2124                 }
2125         }
2126         return (packet_length);
2127 }
2128
2129
2130 /* -- protocol input */
2131
2132 /* ARGSUSED */
2133 void
2134 channel_input_data(int type, u_int32_t seq, void *ctxt)
2135 {
2136         int id;
2137         char *data;
2138         u_int data_len;
2139         Channel *c;
2140
2141         /* Get the channel number and verify it. */
2142         id = packet_get_int();
2143         c = channel_lookup(id);
2144         if (c == NULL)
2145                 packet_disconnect("Received data for nonexistent channel %d.", id);
2146
2147         /* Ignore any data for non-open channels (might happen on close) */
2148         if (c->type != SSH_CHANNEL_OPEN &&
2149             c->type != SSH_CHANNEL_X11_OPEN)
2150                 return;
2151
2152         /* Get the data. */
2153         data = packet_get_string_ptr(&data_len);
2154
2155         /*
2156          * Ignore data for protocol > 1.3 if output end is no longer open.
2157          * For protocol 2 the sending side is reducing its window as it sends
2158          * data, so we must 'fake' consumption of the data in order to ensure
2159          * that window updates are sent back.  Otherwise the connection might
2160          * deadlock.
2161          */
2162         if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2163                 if (compat20) {
2164                         c->local_window -= data_len;
2165                         c->local_consumed += data_len;
2166                 }
2167                 return;
2168         }
2169
2170         if (compat20) {
2171                 if (data_len > c->local_maxpacket) {
2172                         logit("channel %d: rcvd big packet %d, maxpack %d",
2173                             c->self, data_len, c->local_maxpacket);
2174                 }
2175                 if (data_len > c->local_window) {
2176                         logit("channel %d: rcvd too much data %d, win %d",
2177                             c->self, data_len, c->local_window);
2178                         return;
2179                 }
2180                 c->local_window -= data_len;
2181         }
2182         if (c->datagram)
2183                 buffer_put_string(&c->output, data, data_len);
2184         else
2185                 buffer_append(&c->output, data, data_len);
2186         packet_check_eom();
2187 }
2188
2189 /* ARGSUSED */
2190 void
2191 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2192 {
2193         int id;
2194         char *data;
2195         u_int data_len, tcode;
2196         Channel *c;
2197
2198         /* Get the channel number and verify it. */
2199         id = packet_get_int();
2200         c = channel_lookup(id);
2201
2202         if (c == NULL)
2203                 packet_disconnect("Received extended_data for bad channel %d.", id);
2204         if (c->type != SSH_CHANNEL_OPEN) {
2205                 logit("channel %d: ext data for non open", id);
2206                 return;
2207         }
2208         if (c->flags & CHAN_EOF_RCVD) {
2209                 if (datafellows & SSH_BUG_EXTEOF)
2210                         debug("channel %d: accepting ext data after eof", id);
2211                 else
2212                         packet_disconnect("Received extended_data after EOF "
2213                             "on channel %d.", id);
2214         }
2215         tcode = packet_get_int();
2216         if (c->efd == -1 ||
2217             c->extended_usage != CHAN_EXTENDED_WRITE ||
2218             tcode != SSH2_EXTENDED_DATA_STDERR) {
2219                 logit("channel %d: bad ext data", c->self);
2220                 return;
2221         }
2222         data = packet_get_string(&data_len);
2223         packet_check_eom();
2224         if (data_len > c->local_window) {
2225                 logit("channel %d: rcvd too much extended_data %d, win %d",
2226                     c->self, data_len, c->local_window);
2227                 xfree(data);
2228                 return;
2229         }
2230         debug2("channel %d: rcvd ext data %d", c->self, data_len);
2231         c->local_window -= data_len;
2232         buffer_append(&c->extended, data, data_len);
2233         xfree(data);
2234 }
2235
2236 /* ARGSUSED */
2237 void
2238 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2239 {
2240         int id;
2241         Channel *c;
2242
2243         id = packet_get_int();
2244         packet_check_eom();
2245         c = channel_lookup(id);
2246         if (c == NULL)
2247                 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2248         chan_rcvd_ieof(c);
2249
2250         /* XXX force input close */
2251         if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2252                 debug("channel %d: FORCE input drain", c->self);
2253                 c->istate = CHAN_INPUT_WAIT_DRAIN;
2254                 if (buffer_len(&c->input) == 0)
2255                         chan_ibuf_empty(c);
2256         }
2257
2258 }
2259
2260 /* ARGSUSED */
2261 void
2262 channel_input_close(int type, u_int32_t seq, void *ctxt)
2263 {
2264         int id;
2265         Channel *c;
2266
2267         id = packet_get_int();
2268         packet_check_eom();
2269         c = channel_lookup(id);
2270         if (c == NULL)
2271                 packet_disconnect("Received close for nonexistent channel %d.", id);
2272
2273         /*
2274          * Send a confirmation that we have closed the channel and no more
2275          * data is coming for it.
2276          */
2277         packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2278         packet_put_int(c->remote_id);
2279         packet_send();
2280
2281         /*
2282          * If the channel is in closed state, we have sent a close request,
2283          * and the other side will eventually respond with a confirmation.
2284          * Thus, we cannot free the channel here, because then there would be
2285          * no-one to receive the confirmation.  The channel gets freed when
2286          * the confirmation arrives.
2287          */
2288         if (c->type != SSH_CHANNEL_CLOSED) {
2289                 /*
2290                  * Not a closed channel - mark it as draining, which will
2291                  * cause it to be freed later.
2292                  */
2293                 buffer_clear(&c->input);
2294                 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2295         }
2296 }
2297
2298 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2299 /* ARGSUSED */
2300 void
2301 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2302 {
2303         int id = packet_get_int();
2304         Channel *c = channel_lookup(id);
2305
2306         packet_check_eom();
2307         if (c == NULL)
2308                 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2309         chan_rcvd_oclose(c);
2310 }
2311
2312 /* ARGSUSED */
2313 void
2314 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2315 {
2316         int id = packet_get_int();
2317         Channel *c = channel_lookup(id);
2318
2319         packet_check_eom();
2320         if (c == NULL)
2321                 packet_disconnect("Received close confirmation for "
2322                     "out-of-range channel %d.", id);
2323         if (c->type != SSH_CHANNEL_CLOSED)
2324                 packet_disconnect("Received close confirmation for "
2325                     "non-closed channel %d (type %d).", id, c->type);
2326         channel_free(c);
2327 }
2328
2329 /* ARGSUSED */
2330 void
2331 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2332 {
2333         int id, remote_id;
2334         Channel *c;
2335
2336         id = packet_get_int();
2337         c = channel_lookup(id);
2338
2339         if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2340                 packet_disconnect("Received open confirmation for "
2341                     "non-opening channel %d.", id);
2342         remote_id = packet_get_int();
2343         /* Record the remote channel number and mark that the channel is now open. */
2344         c->remote_id = remote_id;
2345         c->type = SSH_CHANNEL_OPEN;
2346
2347         if (compat20) {
2348                 c->remote_window = packet_get_int();
2349                 c->remote_maxpacket = packet_get_int();
2350                 if (c->open_confirm) {
2351                         debug2("callback start");
2352                         c->open_confirm(c->self, c->open_confirm_ctx);
2353                         debug2("callback done");
2354                 }
2355                 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2356                     c->remote_window, c->remote_maxpacket);
2357         }
2358         packet_check_eom();
2359 }
2360
2361 static char *
2362 reason2txt(int reason)
2363 {
2364         switch (reason) {
2365         case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2366                 return "administratively prohibited";
2367         case SSH2_OPEN_CONNECT_FAILED:
2368                 return "connect failed";
2369         case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2370                 return "unknown channel type";
2371         case SSH2_OPEN_RESOURCE_SHORTAGE:
2372                 return "resource shortage";
2373         }
2374         return "unknown reason";
2375 }
2376
2377 /* ARGSUSED */
2378 void
2379 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2380 {
2381         int id, reason;
2382         char *msg = NULL, *lang = NULL;
2383         Channel *c;
2384
2385         id = packet_get_int();
2386         c = channel_lookup(id);
2387
2388         if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2389                 packet_disconnect("Received open failure for "
2390                     "non-opening channel %d.", id);
2391         if (compat20) {
2392                 reason = packet_get_int();
2393                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2394                         msg  = packet_get_string(NULL);
2395                         lang = packet_get_string(NULL);
2396                 }
2397                 logit("channel %d: open failed: %s%s%s", id,
2398                     reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2399                 if (msg != NULL)
2400                         xfree(msg);
2401                 if (lang != NULL)
2402                         xfree(lang);
2403         }
2404         packet_check_eom();
2405         /* Schedule the channel for cleanup/deletion. */
2406         chan_mark_dead(c);
2407 }
2408
2409 /* ARGSUSED */
2410 void
2411 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2412 {
2413         Channel *c;
2414         int id;
2415         u_int adjust;
2416
2417         if (!compat20)
2418                 return;
2419
2420         /* Get the channel number and verify it. */
2421         id = packet_get_int();
2422         c = channel_lookup(id);
2423
2424         if (c == NULL) {
2425                 logit("Received window adjust for non-open channel %d.", id);
2426                 return;
2427         }
2428         adjust = packet_get_int();
2429         packet_check_eom();
2430         debug2("channel %d: rcvd adjust %u", id, adjust);
2431         c->remote_window += adjust;
2432 }
2433
2434 /* ARGSUSED */
2435 void
2436 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2437 {
2438         Channel *c = NULL;
2439         u_short host_port;
2440         char *host, *originator_string;
2441         int remote_id;
2442
2443         remote_id = packet_get_int();
2444         host = packet_get_string(NULL);
2445         host_port = packet_get_int();
2446
2447         if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2448                 originator_string = packet_get_string(NULL);
2449         } else {
2450                 originator_string = xstrdup("unknown (remote did not supply name)");
2451         }
2452         packet_check_eom();
2453         c = channel_connect_to(host, host_port,
2454             "connected socket", originator_string);
2455         xfree(originator_string);
2456         xfree(host);
2457         if (c == NULL) {
2458                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2459                 packet_put_int(remote_id);
2460                 packet_send();
2461         } else
2462                 c->remote_id = remote_id;
2463 }
2464
2465 /* ARGSUSED */
2466 void
2467 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2468 {
2469         Channel *c;
2470         struct channel_confirm *cc;
2471         int id;
2472
2473         /* Reset keepalive timeout */
2474         packet_set_alive_timeouts(0);
2475
2476         id = packet_get_int();
2477         packet_check_eom();
2478
2479         debug2("channel_input_status_confirm: type %d id %d", type, id);
2480
2481         if ((c = channel_lookup(id)) == NULL) {
2482                 logit("channel_input_status_confirm: %d: unknown", id);
2483                 return;
2484         }
2485         ;
2486         if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2487                 return;
2488         cc->cb(type, c, cc->ctx);
2489         TAILQ_REMOVE(&c->status_confirms, cc, entry);
2490         bzero(cc, sizeof(*cc));
2491         xfree(cc);
2492 }
2493
2494 /* -- tcp forwarding */
2495
2496 void
2497 channel_set_af(int af)
2498 {
2499         IPv4or6 = af;
2500 }
2501
2502
2503 void
2504 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size)
2505 {
2506         hpn_disabled = external_hpn_disabled;
2507         hpn_buffer_size = external_hpn_buffer_size;
2508         debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size);
2509 }
2510
2511 static int
2512 channel_setup_fwd_listener(int type, const char *listen_addr,
2513     u_short listen_port, int *allocated_listen_port,
2514     const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2515 {
2516         Channel *c;
2517         int sock, r, success = 0, wildcard = 0, is_client;
2518         struct addrinfo hints, *ai, *aitop;
2519         const char *host, *addr;
2520         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2521         in_port_t *lport_p;
2522
2523         host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2524             listen_addr : host_to_connect;
2525         is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2526
2527         if (host == NULL) {
2528                 error("No forward host name.");
2529                 return 0;
2530         }
2531         if (strlen(host) >= NI_MAXHOST) {
2532                 error("Forward host name too long.");
2533                 return 0;
2534         }
2535
2536         /*
2537          * Determine whether or not a port forward listens to loopback,
2538          * specified address or wildcard. On the client, a specified bind
2539          * address will always override gateway_ports. On the server, a
2540          * gateway_ports of 1 (``yes'') will override the client's
2541          * specification and force a wildcard bind, whereas a value of 2
2542          * (``clientspecified'') will bind to whatever address the client
2543          * asked for.
2544          *
2545          * Special-case listen_addrs are:
2546          *
2547          * "0.0.0.0"               -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2548          * "" (empty string), "*"  -> wildcard v4/v6
2549          * "localhost"             -> loopback v4/v6
2550          */
2551         addr = NULL;
2552         if (listen_addr == NULL) {
2553                 /* No address specified: default to gateway_ports setting */
2554                 if (gateway_ports)
2555                         wildcard = 1;
2556         } else if (gateway_ports || is_client) {
2557                 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2558                     strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2559                     *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2560                     (!is_client && gateway_ports == 1))
2561                         wildcard = 1;
2562                 else if (strcmp(listen_addr, "localhost") != 0)
2563                         addr = listen_addr;
2564         }
2565
2566         debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2567             type, wildcard, (addr == NULL) ? "NULL" : addr);
2568
2569         /*
2570          * getaddrinfo returns a loopback address if the hostname is
2571          * set to NULL and hints.ai_flags is not AI_PASSIVE
2572          */
2573         memset(&hints, 0, sizeof(hints));
2574         hints.ai_family = IPv4or6;
2575         hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2576         hints.ai_socktype = SOCK_STREAM;
2577         snprintf(strport, sizeof strport, "%d", listen_port);
2578         if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2579                 if (addr == NULL) {
2580                         /* This really shouldn't happen */
2581                         packet_disconnect("getaddrinfo: fatal error: %s",
2582                             ssh_gai_strerror(r));
2583                 } else {
2584                         error("channel_setup_fwd_listener: "
2585                             "getaddrinfo(%.64s): %s", addr,
2586                             ssh_gai_strerror(r));
2587                 }
2588                 return 0;
2589         }
2590         if (allocated_listen_port != NULL)
2591                 *allocated_listen_port = 0;
2592         for (ai = aitop; ai; ai = ai->ai_next) {
2593                 switch (ai->ai_family) {
2594                 case AF_INET:
2595                         lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2596                             sin_port;
2597                         break;
2598                 case AF_INET6:
2599                         lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2600                             sin6_port;
2601                         break;
2602                 default:
2603                         continue;
2604                 }
2605                 /*
2606                  * If allocating a port for -R forwards, then use the
2607                  * same port for all address families.
2608                  */
2609                 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2610                     allocated_listen_port != NULL && *allocated_listen_port > 0)
2611                         *lport_p = htons(*allocated_listen_port);
2612
2613                 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2614                     strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2615                         error("channel_setup_fwd_listener: getnameinfo failed");
2616                         continue;
2617                 }
2618                 /* Create a port to listen for the host. */
2619                 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2620                 if (sock < 0) {
2621                         /* this is no error since kernel may not support ipv6 */
2622                         verbose("socket: %.100s", strerror(errno));
2623                         continue;
2624                 }
2625
2626                 channel_set_reuseaddr(sock);
2627
2628                 debug("Local forwarding listening on %s port %s.",
2629                     ntop, strport);
2630
2631                 /* Bind the socket to the address. */
2632                 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2633                         /* address can be in use ipv6 address is already bound */
2634                         if (!ai->ai_next)
2635                                 error("bind: %.100s", strerror(errno));
2636                         else
2637                                 verbose("bind: %.100s", strerror(errno));
2638
2639                         close(sock);
2640                         continue;
2641                 }
2642                 /* Start listening for connections on the socket. */
2643                 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2644                         error("listen: %.100s", strerror(errno));
2645                         close(sock);
2646                         continue;
2647                 }
2648
2649                 /*
2650                  * listen_port == 0 requests a dynamically allocated port -
2651                  * record what we got.
2652                  */
2653                 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2654                     allocated_listen_port != NULL &&
2655                     *allocated_listen_port == 0) {
2656                         *allocated_listen_port = get_sock_port(sock, 1);
2657                         debug("Allocated listen port %d",
2658                             *allocated_listen_port);
2659                 }
2660
2661                 /* Allocate a channel number for the socket. */
2662                 /* explicitly test for hpn disabled option. if true use smaller window size */
2663                 if (hpn_disabled)
2664                 c = channel_new("port listener", type, sock, sock, -1,
2665                     CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2666                     0, "port listener", 1);
2667                 else
2668                         c = channel_new("port listener", type, sock, sock, -1,
2669                           hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2670                           0, "port listener", 1);
2671                 c->path = xstrdup(host);
2672                 c->host_port = port_to_connect;
2673                 c->listening_port = listen_port;
2674                 success = 1;
2675         }
2676         if (success == 0)
2677                 error("channel_setup_fwd_listener: cannot listen to port: %d",
2678                     listen_port);
2679         freeaddrinfo(aitop);
2680         return success;
2681 }
2682
2683 int
2684 channel_cancel_rport_listener(const char *host, u_short port)
2685 {
2686         u_int i;
2687         int found = 0;
2688
2689         for (i = 0; i < channels_alloc; i++) {
2690                 Channel *c = channels[i];
2691
2692                 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2693                     strcmp(c->path, host) == 0 && c->listening_port == port) {
2694                         debug2("%s: close channel %d", __func__, i);
2695                         channel_free(c);
2696                         found = 1;
2697                 }
2698         }
2699
2700         return (found);
2701 }
2702
2703 /* protocol local port fwd, used by ssh (and sshd in v1) */
2704 int
2705 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2706     const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2707 {
2708         return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2709             listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2710             gateway_ports);
2711 }
2712
2713 /* protocol v2 remote port fwd, used by sshd */
2714 int
2715 channel_setup_remote_fwd_listener(const char *listen_address,
2716     u_short listen_port, int *allocated_listen_port, int gateway_ports)
2717 {
2718         return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2719             listen_address, listen_port, allocated_listen_port,
2720             NULL, 0, gateway_ports);
2721 }
2722
2723 /*
2724  * Initiate forwarding of connections to port "port" on remote host through
2725  * the secure channel to host:port from local side.
2726  */
2727
2728 int
2729 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2730     const char *host_to_connect, u_short port_to_connect)
2731 {
2732         int type, success = 0;
2733
2734         /* Record locally that connection to this host/port is permitted. */
2735         if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2736                 fatal("channel_request_remote_forwarding: too many forwards");
2737
2738         /* Send the forward request to the remote side. */
2739         if (compat20) {
2740                 const char *address_to_bind;
2741                 if (listen_host == NULL) {
2742                         if (datafellows & SSH_BUG_RFWD_ADDR)
2743                                 address_to_bind = "127.0.0.1";
2744                         else
2745                                 address_to_bind = "localhost";
2746                 } else if (*listen_host == '\0' ||
2747                            strcmp(listen_host, "*") == 0) {
2748                         if (datafellows & SSH_BUG_RFWD_ADDR)
2749                                 address_to_bind = "0.0.0.0";
2750                         else
2751                                 address_to_bind = "";
2752                 } else
2753                         address_to_bind = listen_host;
2754
2755                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2756                 packet_put_cstring("tcpip-forward");
2757                 packet_put_char(1);                     /* boolean: want reply */
2758                 packet_put_cstring(address_to_bind);
2759                 packet_put_int(listen_port);
2760                 packet_send();
2761                 packet_write_wait();
2762                 /* Assume that server accepts the request */
2763                 success = 1;
2764         } else {
2765                 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2766                 packet_put_int(listen_port);
2767                 packet_put_cstring(host_to_connect);
2768                 packet_put_int(port_to_connect);
2769                 packet_send();
2770                 packet_write_wait();
2771
2772                 /* Wait for response from the remote side. */
2773                 type = packet_read();
2774                 switch (type) {
2775                 case SSH_SMSG_SUCCESS:
2776                         success = 1;
2777                         break;
2778                 case SSH_SMSG_FAILURE:
2779                         break;
2780                 default:
2781                         /* Unknown packet */
2782                         packet_disconnect("Protocol error for port forward request:"
2783                             "received packet type %d.", type);
2784                 }
2785         }
2786         if (success) {
2787                 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2788                 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2789                 permitted_opens[num_permitted_opens].listen_port = listen_port;
2790                 num_permitted_opens++;
2791         }
2792         return (success ? 0 : -1);
2793 }
2794
2795 /*
2796  * Request cancellation of remote forwarding of connection host:port from
2797  * local side.
2798  */
2799 void
2800 channel_request_rforward_cancel(const char *host, u_short port)
2801 {
2802         int i;
2803
2804         if (!compat20)
2805                 return;
2806
2807         for (i = 0; i < num_permitted_opens; i++) {
2808                 if (permitted_opens[i].host_to_connect != NULL &&
2809                     permitted_opens[i].listen_port == port)
2810                         break;
2811         }
2812         if (i >= num_permitted_opens) {
2813                 debug("%s: requested forward not found", __func__);
2814                 return;
2815         }
2816         packet_start(SSH2_MSG_GLOBAL_REQUEST);
2817         packet_put_cstring("cancel-tcpip-forward");
2818         packet_put_char(0);
2819         packet_put_cstring(host == NULL ? "" : host);
2820         packet_put_int(port);
2821         packet_send();
2822
2823         permitted_opens[i].listen_port = 0;
2824         permitted_opens[i].port_to_connect = 0;
2825         xfree(permitted_opens[i].host_to_connect);
2826         permitted_opens[i].host_to_connect = NULL;
2827 }
2828
2829 /*
2830  * This is called after receiving CHANNEL_FORWARDING_REQUEST.  This initates
2831  * listening for the port, and sends back a success reply (or disconnect
2832  * message if there was an error).
2833  */
2834 int
2835 channel_input_port_forward_request(int is_root, int gateway_ports)
2836 {
2837         u_short port, host_port;
2838         int success = 0;
2839         char *hostname;
2840
2841         /* Get arguments from the packet. */
2842         port = packet_get_int();
2843         hostname = packet_get_string(NULL);
2844         host_port = packet_get_int();
2845
2846 #ifndef HAVE_CYGWIN
2847         /*
2848          * Check that an unprivileged user is not trying to forward a
2849          * privileged port.
2850          */
2851         if (port < IPPORT_RESERVED && !is_root)
2852                 packet_disconnect(
2853                     "Requested forwarding of port %d but user is not root.",
2854                     port);
2855         if (host_port == 0)
2856                 packet_disconnect("Dynamic forwarding denied.");
2857 #endif
2858
2859         /* Initiate forwarding */
2860         success = channel_setup_local_fwd_listener(NULL, port, hostname,
2861             host_port, gateway_ports);
2862
2863         /* Free the argument string. */
2864         xfree(hostname);
2865
2866         return (success ? 0 : -1);
2867 }
2868
2869 /*
2870  * Permits opening to any host/port if permitted_opens[] is empty.  This is
2871  * usually called by the server, because the user could connect to any port
2872  * anyway, and the server has no way to know but to trust the client anyway.
2873  */
2874 void
2875 channel_permit_all_opens(void)
2876 {
2877         if (num_permitted_opens == 0)
2878                 all_opens_permitted = 1;
2879 }
2880
2881 void
2882 channel_add_permitted_opens(char *host, int port)
2883 {
2884         if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2885                 fatal("channel_add_permitted_opens: too many forwards");
2886         debug("allow port forwarding to host %s port %d", host, port);
2887
2888         permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
2889         permitted_opens[num_permitted_opens].port_to_connect = port;
2890         num_permitted_opens++;
2891
2892         all_opens_permitted = 0;
2893 }
2894
2895 int
2896 channel_add_adm_permitted_opens(char *host, int port)
2897 {
2898         if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
2899                 fatal("channel_add_adm_permitted_opens: too many forwards");
2900         debug("config allows port forwarding to host %s port %d", host, port);
2901
2902         permitted_adm_opens[num_adm_permitted_opens].host_to_connect
2903              = xstrdup(host);
2904         permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
2905         return ++num_adm_permitted_opens;
2906 }
2907
2908 void
2909 channel_clear_permitted_opens(void)
2910 {
2911         int i;
2912
2913         for (i = 0; i < num_permitted_opens; i++)
2914                 if (permitted_opens[i].host_to_connect != NULL)
2915                         xfree(permitted_opens[i].host_to_connect);
2916         num_permitted_opens = 0;
2917 }
2918
2919 void
2920 channel_clear_adm_permitted_opens(void)
2921 {
2922         int i;
2923
2924         for (i = 0; i < num_adm_permitted_opens; i++)
2925                 if (permitted_adm_opens[i].host_to_connect != NULL)
2926                         xfree(permitted_adm_opens[i].host_to_connect);
2927         num_adm_permitted_opens = 0;
2928 }
2929
2930 void
2931 channel_print_adm_permitted_opens(void)
2932 {
2933         int i;
2934
2935         printf("permitopen");
2936         if (num_adm_permitted_opens == 0) {
2937                 printf(" any\n");
2938                 return;
2939         }
2940         for (i = 0; i < num_adm_permitted_opens; i++)
2941                 if (permitted_adm_opens[i].host_to_connect != NULL)
2942                         printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
2943                             permitted_adm_opens[i].port_to_connect);
2944         printf("\n");
2945 }
2946
2947 /* Try to start non-blocking connect to next host in cctx list */
2948 static int
2949 connect_next(struct channel_connect *cctx)
2950 {
2951         int sock, saved_errno;
2952         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2953
2954         for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
2955                 if (cctx->ai->ai_family != AF_INET &&
2956                     cctx->ai->ai_family != AF_INET6)
2957                         continue;
2958                 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
2959                     ntop, sizeof(ntop), strport, sizeof(strport),
2960                     NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2961                         error("connect_next: getnameinfo failed");
2962                         continue;
2963                 }
2964                 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
2965                     cctx->ai->ai_protocol)) == -1) {
2966                         if (cctx->ai->ai_next == NULL)
2967                                 error("socket: %.100s", strerror(errno));
2968                         else
2969                                 verbose("socket: %.100s", strerror(errno));
2970                         continue;
2971                 }
2972                 if (set_nonblock(sock) == -1)
2973                         fatal("%s: set_nonblock(%d)", __func__, sock);
2974                 if (connect(sock, cctx->ai->ai_addr,
2975                     cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
2976                         debug("connect_next: host %.100s ([%.100s]:%s): "
2977                             "%.100s", cctx->host, ntop, strport,
2978                             strerror(errno));
2979                         saved_errno = errno;
2980                         close(sock);
2981                         errno = saved_errno;
2982                         continue;       /* fail -- try next */
2983                 }
2984                 debug("connect_next: host %.100s ([%.100s]:%s) "
2985                     "in progress, fd=%d", cctx->host, ntop, strport, sock);
2986                 cctx->ai = cctx->ai->ai_next;
2987                 set_nodelay(sock);
2988                 return sock;
2989         }
2990         return -1;
2991 }
2992
2993 static void
2994 channel_connect_ctx_free(struct channel_connect *cctx)
2995 {
2996         xfree(cctx->host);
2997         if (cctx->aitop)
2998                 freeaddrinfo(cctx->aitop);
2999         bzero(cctx, sizeof(*cctx));
3000         cctx->host = NULL;
3001         cctx->ai = cctx->aitop = NULL;
3002 }
3003
3004 /* Return CONNECTING channel to remote host, port */
3005 static Channel *
3006 connect_to(const char *host, u_short port, char *ctype, char *rname)
3007 {
3008         struct addrinfo hints;
3009         int gaierr;
3010         int sock = -1;
3011         char strport[NI_MAXSERV];
3012         struct channel_connect cctx;
3013         Channel *c;
3014
3015         memset(&cctx, 0, sizeof(cctx));
3016         memset(&hints, 0, sizeof(hints));
3017         hints.ai_family = IPv4or6;
3018         hints.ai_socktype = SOCK_STREAM;
3019         snprintf(strport, sizeof strport, "%d", port);
3020         if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
3021                 error("connect_to %.100s: unknown host (%s)", host,
3022                     ssh_gai_strerror(gaierr));
3023                 return NULL;
3024         }
3025
3026         cctx.host = xstrdup(host);
3027         cctx.port = port;
3028         cctx.ai = cctx.aitop;
3029
3030         if ((sock = connect_next(&cctx)) == -1) {
3031                 error("connect to %.100s port %d failed: %s",
3032                     host, port, strerror(errno));
3033                 channel_connect_ctx_free(&cctx);
3034                 return NULL;
3035         }
3036         c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3037             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3038         c->connect_ctx = cctx;
3039         return c;
3040 }
3041
3042 Channel *
3043 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3044 {
3045         int i;
3046
3047         for (i = 0; i < num_permitted_opens; i++) {
3048                 if (permitted_opens[i].host_to_connect != NULL &&
3049                     permitted_opens[i].listen_port == listen_port) {
3050                         return connect_to(
3051                             permitted_opens[i].host_to_connect,
3052                             permitted_opens[i].port_to_connect, ctype, rname);
3053                 }
3054         }
3055         error("WARNING: Server requests forwarding for unknown listen_port %d",
3056             listen_port);
3057         return NULL;
3058 }
3059
3060 /* Check if connecting to that port is permitted and connect. */
3061 Channel *
3062 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3063 {
3064         int i, permit, permit_adm = 1;
3065
3066         permit = all_opens_permitted;
3067         if (!permit) {
3068                 for (i = 0; i < num_permitted_opens; i++)
3069                         if (permitted_opens[i].host_to_connect != NULL &&
3070                             permitted_opens[i].port_to_connect == port &&
3071                             strcmp(permitted_opens[i].host_to_connect, host) == 0)
3072                                 permit = 1;
3073         }
3074
3075         if (num_adm_permitted_opens > 0) {
3076                 permit_adm = 0;
3077                 for (i = 0; i < num_adm_permitted_opens; i++)
3078                         if (permitted_adm_opens[i].host_to_connect != NULL &&
3079                             permitted_adm_opens[i].port_to_connect == port &&
3080                             strcmp(permitted_adm_opens[i].host_to_connect, host)
3081                             == 0)
3082                                 permit_adm = 1;
3083         }
3084
3085         if (!permit || !permit_adm) {
3086                 logit("Received request to connect to host %.100s port %d, "
3087                     "but the request was denied.", host, port);
3088                 return NULL;
3089         }
3090         return connect_to(host, port, ctype, rname);
3091 }
3092
3093 void
3094 channel_send_window_changes(void)
3095 {
3096         u_int i;
3097         struct winsize ws;
3098
3099         for (i = 0; i < channels_alloc; i++) {
3100                 if (channels[i] == NULL || !channels[i]->client_tty ||
3101                     channels[i]->type != SSH_CHANNEL_OPEN)
3102                         continue;
3103                 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3104                         continue;
3105                 channel_request_start(i, "window-change", 0);
3106                 packet_put_int((u_int)ws.ws_col);
3107                 packet_put_int((u_int)ws.ws_row);
3108                 packet_put_int((u_int)ws.ws_xpixel);
3109                 packet_put_int((u_int)ws.ws_ypixel);
3110                 packet_send();
3111         }
3112 }
3113
3114 /* -- X11 forwarding */
3115
3116 /*
3117  * Creates an internet domain socket for listening for X11 connections.
3118  * Returns 0 and a suitable display number for the DISPLAY variable
3119  * stored in display_numberp , or -1 if an error occurs.
3120  */
3121 int
3122 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3123     int single_connection, u_int *display_numberp, int **chanids)
3124 {
3125         Channel *nc = NULL;
3126         int display_number, sock;
3127         u_short port;
3128         struct addrinfo hints, *ai, *aitop;
3129         char strport[NI_MAXSERV];
3130         int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3131
3132         if (chanids == NULL)
3133                 return -1;
3134
3135         for (display_number = x11_display_offset;
3136             display_number < MAX_DISPLAYS;
3137             display_number++) {
3138                 port = 6000 + display_number;
3139                 memset(&hints, 0, sizeof(hints));
3140                 hints.ai_family = IPv4or6;
3141                 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3142                 hints.ai_socktype = SOCK_STREAM;
3143                 snprintf(strport, sizeof strport, "%d", port);
3144                 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3145                         error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3146                         return -1;
3147                 }
3148                 for (ai = aitop; ai; ai = ai->ai_next) {
3149                         if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3150                                 continue;
3151                         sock = socket(ai->ai_family, ai->ai_socktype,
3152                             ai->ai_protocol);
3153                         if (sock < 0) {
3154                                 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
3155                                         error("socket: %.100s", strerror(errno));
3156                                         freeaddrinfo(aitop);
3157                                         return -1;
3158                                 } else {
3159                                         debug("x11_create_display_inet: Socket family %d not supported",
3160                                                  ai->ai_family);
3161                                         continue;
3162                                 }
3163                         }
3164 #ifdef IPV6_V6ONLY
3165                         if (ai->ai_family == AF_INET6) {
3166                                 int on = 1;
3167                                 if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
3168                                         error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
3169                         }
3170 #endif
3171                         if (x11_use_localhost)
3172                                 channel_set_reuseaddr(sock);
3173                         if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3174                                 debug2("bind port %d: %.100s", port, strerror(errno));
3175                                 close(sock);
3176
3177                                 for (n = 0; n < num_socks; n++) {
3178                                         close(socks[n]);
3179                                 }
3180                                 num_socks = 0;
3181                                 break;
3182                         }
3183                         socks[num_socks++] = sock;
3184                         if (num_socks == NUM_SOCKS)
3185                                 break;
3186                 }
3187                 freeaddrinfo(aitop);
3188                 if (num_socks > 0)
3189                         break;
3190         }
3191         if (display_number >= MAX_DISPLAYS) {
3192                 error("Failed to allocate internet-domain X11 display socket.");
3193                 return -1;
3194         }
3195         /* Start listening for connections on the socket. */
3196         for (n = 0; n < num_socks; n++) {
3197                 sock = socks[n];
3198                 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3199                         error("listen: %.100s", strerror(errno));
3200                         close(sock);
3201                         return -1;
3202                 }
3203         }
3204
3205         /* Allocate a channel for each socket. */
3206         *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3207         for (n = 0; n < num_socks; n++) {
3208                 sock = socks[n];
3209                 /* Is this really necassary? */
3210                 if (hpn_disabled)
3211                 nc = channel_new("x11 listener",
3212                     SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3213                     CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3214                     0, "X11 inet listener", 1);
3215                 else
3216                         nc = channel_new("x11 listener",
3217                             SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3218                             hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
3219                             0, "X11 inet listener", 1);
3220                 nc->single_connection = single_connection;
3221                 (*chanids)[n] = nc->self;
3222         }
3223         (*chanids)[n] = -1;
3224
3225         /* Return the display number for the DISPLAY environment variable. */
3226         *display_numberp = display_number;
3227         return (0);
3228 }
3229
3230 static int
3231 connect_local_xsocket_path(const char *pathname)
3232 {
3233         int sock;
3234         struct sockaddr_un addr;
3235
3236         sock = socket(AF_UNIX, SOCK_STREAM, 0);
3237         if (sock < 0)
3238                 error("socket: %.100s", strerror(errno));
3239         memset(&addr, 0, sizeof(addr));
3240         addr.sun_family = AF_UNIX;
3241         strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3242         if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3243                 return sock;
3244         close(sock);
3245         error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3246         return -1;
3247 }
3248
3249 static int
3250 connect_local_xsocket(u_int dnr)
3251 {
3252         char buf[1024];
3253         snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3254         return connect_local_xsocket_path(buf);
3255 }
3256
3257 int
3258 x11_connect_display(void)
3259 {
3260         u_int display_number;
3261         const char *display;
3262         char buf[1024], *cp;
3263         struct addrinfo hints, *ai, *aitop;
3264         char strport[NI_MAXSERV];
3265         int gaierr, sock = 0;
3266
3267         /* Try to open a socket for the local X server. */
3268         display = getenv("DISPLAY");
3269         if (!display) {
3270                 error("DISPLAY not set.");
3271                 return -1;
3272         }
3273         /*
3274          * Now we decode the value of the DISPLAY variable and make a
3275          * connection to the real X server.
3276          */
3277
3278         /* Check if the display is from launchd. */
3279 #ifdef __APPLE__
3280         if (strncmp(display, "/tmp/launch", 11) == 0) {
3281                 sock = connect_local_xsocket_path(display);
3282                 if (sock < 0)
3283                         return -1;
3284
3285                 /* OK, we now have a connection to the display. */
3286                 return sock;
3287         }
3288 #endif
3289         /*
3290          * Check if it is a unix domain socket.  Unix domain displays are in
3291          * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3292          */
3293         if (strncmp(display, "unix:", 5) == 0 ||
3294             display[0] == ':') {
3295                 /* Connect to the unix domain socket. */
3296                 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3297                         error("Could not parse display number from DISPLAY: %.100s",
3298                             display);
3299                         return -1;
3300                 }
3301                 /* Create a socket. */
3302                 sock = connect_local_xsocket(display_number);
3303                 if (sock < 0)
3304                         return -1;
3305
3306                 /* OK, we now have a connection to the display. */
3307                 return sock;
3308         }
3309         /*
3310          * Connect to an inet socket.  The DISPLAY value is supposedly
3311          * hostname:d[.s], where hostname may also be numeric IP address.
3312          */
3313         strlcpy(buf, display, sizeof(buf));
3314         cp = strchr(buf, ':');
3315         if (!cp) {
3316                 error("Could not find ':' in DISPLAY: %.100s", display);
3317                 return -1;
3318         }
3319         *cp = 0;
3320         /* buf now contains the host name.  But first we parse the display number. */
3321         if (sscanf(cp + 1, "%u", &display_number) != 1) {
3322                 error("Could not parse display number from DISPLAY: %.100s",
3323                     display);
3324                 return -1;
3325         }
3326
3327         /* Look up the host address */
3328         memset(&hints, 0, sizeof(hints));
3329         hints.ai_family = IPv4or6;
3330         hints.ai_socktype = SOCK_STREAM;
3331         snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3332         if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3333                 error("%.100s: unknown host. (%s)", buf,
3334                 ssh_gai_strerror(gaierr));
3335                 return -1;
3336         }
3337         for (ai = aitop; ai; ai = ai->ai_next) {
3338                 /* Create a socket. */
3339                 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3340                 if (sock < 0) {
3341                         debug2("socket: %.100s", strerror(errno));
3342                         continue;
3343                 }
3344                 /* Connect it to the display. */
3345                 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3346                         debug2("connect %.100s port %u: %.100s", buf,
3347                             6000 + display_number, strerror(errno));
3348                         close(sock);
3349                         continue;
3350                 }
3351                 /* Success */
3352                 break;
3353         }
3354         freeaddrinfo(aitop);
3355         if (!ai) {
3356                 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3357                     strerror(errno));
3358                 return -1;
3359         }
3360         set_nodelay(sock);
3361         return sock;
3362 }
3363
3364 /*
3365  * This is called when SSH_SMSG_X11_OPEN is received.  The packet contains
3366  * the remote channel number.  We should do whatever we want, and respond
3367  * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3368  */
3369
3370 /* ARGSUSED */
3371 void
3372 x11_input_open(int type, u_int32_t seq, void *ctxt)
3373 {
3374         Channel *c = NULL;
3375         int remote_id, sock = 0;
3376         char *remote_host;
3377
3378         debug("Received X11 open request.");
3379
3380         remote_id = packet_get_int();
3381
3382         if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3383                 remote_host = packet_get_string(NULL);
3384         } else {
3385                 remote_host = xstrdup("unknown (remote did not supply name)");
3386         }
3387         packet_check_eom();
3388
3389         /* Obtain a connection to the real X display. */
3390         sock = x11_connect_display();
3391         if (sock != -1) {
3392                 /* Allocate a channel for this connection. */
3393                 c = channel_new("connected x11 socket",
3394                     SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3395                     remote_host, 1);
3396                 c->remote_id = remote_id;
3397                 c->force_drain = 1;
3398         }
3399         xfree(remote_host);
3400         if (c == NULL) {
3401                 /* Send refusal to the remote host. */
3402                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3403                 packet_put_int(remote_id);
3404         } else {
3405                 /* Send a confirmation to the remote host. */
3406                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3407                 packet_put_int(remote_id);
3408                 packet_put_int(c->self);
3409         }
3410         packet_send();
3411 }
3412
3413 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3414 /* ARGSUSED */
3415 void
3416 deny_input_open(int type, u_int32_t seq, void *ctxt)
3417 {
3418         int rchan = packet_get_int();
3419
3420         switch (type) {
3421         case SSH_SMSG_AGENT_OPEN:
3422                 error("Warning: ssh server tried agent forwarding.");
3423                 break;
3424         case SSH_SMSG_X11_OPEN:
3425                 error("Warning: ssh server tried X11 forwarding.");
3426                 break;
3427         default:
3428                 error("deny_input_open: type %d", type);
3429                 break;
3430         }
3431         error("Warning: this is probably a break-in attempt by a malicious server.");
3432         packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3433         packet_put_int(rchan);
3434         packet_send();
3435 }
3436
3437 /*
3438  * Requests forwarding of X11 connections, generates fake authentication
3439  * data, and enables authentication spoofing.
3440  * This should be called in the client only.
3441  */
3442 void
3443 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3444     const char *proto, const char *data)
3445 {
3446         u_int data_len = (u_int) strlen(data) / 2;
3447         u_int i, value;
3448         char *new_data;
3449         int screen_number;
3450         const char *cp;
3451         u_int32_t rnd = 0;
3452
3453         if (x11_saved_display == NULL)
3454                 x11_saved_display = xstrdup(disp);
3455         else if (strcmp(disp, x11_saved_display) != 0) {
3456                 error("x11_request_forwarding_with_spoofing: different "
3457                     "$DISPLAY already forwarded");
3458                 return;
3459         }
3460
3461         cp = strchr(disp, ':');
3462         if (cp)
3463                 cp = strchr(cp, '.');
3464         if (cp)
3465                 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3466         else
3467                 screen_number = 0;
3468
3469         if (x11_saved_proto == NULL) {
3470                 /* Save protocol name. */
3471                 x11_saved_proto = xstrdup(proto);
3472                 /*
3473                  * Extract real authentication data and generate fake data
3474                  * of the same length.
3475                  */
3476                 x11_saved_data = xmalloc(data_len);
3477                 x11_fake_data = xmalloc(data_len);
3478                 for (i = 0; i < data_len; i++) {
3479                         if (sscanf(data + 2 * i, "%2x", &value) != 1)
3480                                 fatal("x11_request_forwarding: bad "
3481                                     "authentication data: %.100s", data);
3482                         if (i % 4 == 0)
3483                                 rnd = arc4random();
3484                         x11_saved_data[i] = value;
3485                         x11_fake_data[i] = rnd & 0xff;
3486                         rnd >>= 8;
3487                 }
3488                 x11_saved_data_len = data_len;
3489                 x11_fake_data_len = data_len;
3490         }
3491
3492         /* Convert the fake data into hex. */
3493         new_data = tohex(x11_fake_data, data_len);
3494
3495         /* Send the request packet. */
3496         if (compat20) {
3497                 channel_request_start(client_session_id, "x11-req", 0);
3498                 packet_put_char(0);     /* XXX bool single connection */
3499         } else {
3500                 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3501         }
3502         packet_put_cstring(proto);
3503         packet_put_cstring(new_data);
3504         packet_put_int(screen_number);
3505         packet_send();
3506         packet_write_wait();
3507         xfree(new_data);
3508 }
3509
3510
3511 /* -- agent forwarding */
3512
3513 /* Sends a message to the server to request authentication fd forwarding. */
3514
3515 void
3516 auth_request_forwarding(void)
3517 {
3518         packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3519         packet_send();
3520         packet_write_wait();
3521 }