crypto/openssh/channels.c

   1 /* $OpenBSD: channels.c,v 1.311 2011/06/22 22:08:42 djm Exp $ */
   2 /*
   3  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   4  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   5  *                    All rights reserved
   6  * This file contains functions for generic socket connection forwarding.
   7  * There is also code for initiating connection forwarding for X11 connections,
   8  * arbitrary tcp/ip connections, and the authentication agent connection.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  *
  16  * SSH2 support added by Markus Friedl.
  17  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
  18  * Copyright (c) 1999 Dug Song.  All rights reserved.
  19  * Copyright (c) 1999 Theo de Raadt.  All rights reserved.
  20  *
  21  * Redistribution and use in source and binary forms, with or without
  22  * modification, are permitted provided that the following conditions
  23  * are met:
  24  * 1. Redistributions of source code must retain the above copyright
  25  *    notice, this list of conditions and the following disclaimer.
  26  * 2. Redistributions in binary form must reproduce the above copyright
  27  *    notice, this list of conditions and the following disclaimer in the
  28  *    documentation and/or other materials provided with the distribution.
  29  *
  30  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  31  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  32  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  33  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  34  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  35  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  36  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  37  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  38  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  39  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  40  */
  41
  42 #include "includes.h"
  43
  44 #include <sys/types.h>
  45 #include <sys/ioctl.h>
  46 #include <sys/un.h>
  47 #include <sys/socket.h>
  48 #ifdef HAVE_SYS_TIME_H
  49 # include <sys/time.h>
  50 #endif
  51
  52 #include <netinet/in.h>
  53 #include <arpa/inet.h>
  54
  55 #include <errno.h>
  56 #include <fcntl.h>
  57 #include <netdb.h>
  58 #include <stdio.h>
  59 #include <stdlib.h>
  60 #include <string.h>
  61 #include <termios.h>
  62 #include <unistd.h>
  63 #include <stdarg.h>
  64
  65 #include "openbsd-compat/sys-queue.h"
  66 #include "xmalloc.h"
  67 #include "ssh.h"
  68 #include "ssh1.h"
  69 #include "ssh2.h"
  70 #include "packet.h"
  71 #include "log.h"
  72 #include "misc.h"
  73 #include "buffer.h"
  74 #include "channels.h"
  75 #include "compat.h"
  76 #include "canohost.h"
  77 #include "key.h"
  78 #include "authfd.h"
  79 #include "pathnames.h"
  80
  81 /* -- channel core */
  82
  83 /*
  84  * Pointer to an array containing all allocated channels.  The array is
  85  * dynamically extended as needed.
  86  */
  87 static Channel **channels = NULL;
  88
  89 /*
  90  * Size of the channel array.  All slots of the array must always be
  91  * initialized (at least the type field); unused slots set to NULL
  92  */
  93 static u_int channels_alloc = 0;
  94
  95 /*
  96  * Maximum file descriptor value used in any of the channels.  This is
  97  * updated in channel_new.
  98  */
  99 static int channel_max_fd = 0;
 100
 101
 102 /* -- tcp forwarding */
 103
 104 /*
 105  * Data structure for storing which hosts are permitted for forward requests.
 106  * The local sides of any remote forwards are stored in this array to prevent
 107  * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
 108  * network (which might be behind a firewall).
 109  */
 110 typedef struct {
 111         char *host_to_connect;          /* Connect to 'host'. */
 112         u_short port_to_connect;        /* Connect to 'port'. */
 113         u_short listen_port;            /* Remote side should listen port number. */
 114 } ForwardPermission;
 115
 116 /* List of all permitted host/port pairs to connect by the user. */
 117 static ForwardPermission *permitted_opens = NULL;
 118
 119 /* List of all permitted host/port pairs to connect by the admin. */
 120 static ForwardPermission *permitted_adm_opens = NULL;
 121
 122 /* Number of permitted host/port pairs in the array permitted by the user. */
 123 static int num_permitted_opens = 0;
 124
 125 /* Number of permitted host/port pair in the array permitted by the admin. */
 126 static int num_adm_permitted_opens = 0;
 127
 128 /*
 129  * If this is true, all opens are permitted.  This is the case on the server
 130  * on which we have to trust the client anyway, and the user could do
 131  * anything after logging in anyway.
 132  */
 133 static int all_opens_permitted = 0;
 134
 135
 136 /* -- X11 forwarding */
 137
 138 /* Maximum number of fake X11 displays to try. */
 139 #define MAX_DISPLAYS  1000
 140
 141 /* Saved X11 local (client) display. */
 142 static char *x11_saved_display = NULL;
 143
 144 /* Saved X11 authentication protocol name. */
 145 static char *x11_saved_proto = NULL;
 146
 147 /* Saved X11 authentication data.  This is the real data. */
 148 static char *x11_saved_data = NULL;
 149 static u_int x11_saved_data_len = 0;
 150
 151 /*
 152  * Fake X11 authentication data.  This is what the server will be sending us;
 153  * we should replace any occurrences of this by the real data.
 154  */
 155 static u_char *x11_fake_data = NULL;
 156 static u_int x11_fake_data_len;
 157
 158
 159 /* -- agent forwarding */
 160
 161 #define NUM_SOCKS       10
 162
 163 /* AF_UNSPEC or AF_INET or AF_INET6 */
 164 static int IPv4or6 = AF_UNSPEC;
 165
 166 /* helper */
 167 static void port_open_helper(Channel *c, char *rtype);
 168
 169 /* non-blocking connect helpers */
 170 static int connect_next(struct channel_connect *);
 171 static void channel_connect_ctx_free(struct channel_connect *);
 172
 173
 174 static int hpn_disabled = 0;
 175 static int hpn_buffer_size = 2 * 1024 * 1024;
 176
 177 /* -- channel core */
 178
 179
 180
 181 Channel *
 182 channel_by_id(int id)
 183 {
 184         Channel *c;
 185
 186         if (id < 0 || (u_int)id >= channels_alloc) {
 187                 logit("channel_by_id: %d: bad id", id);
 188                 return NULL;
 189         }
 190         c = channels[id];
 191         if (c == NULL) {
 192                 logit("channel_by_id: %d: bad id: channel free", id);
 193                 return NULL;
 194         }
 195         return c;
 196 }
 197
 198 /*
 199  * Returns the channel if it is allowed to receive protocol messages.
 200  * Private channels, like listening sockets, may not receive messages.
 201  */
 202 Channel *
 203 channel_lookup(int id)
 204 {
 205         Channel *c;
 206
 207         if ((c = channel_by_id(id)) == NULL)
 208                 return (NULL);
 209
 210         switch (c->type) {
 211         case SSH_CHANNEL_X11_OPEN:
 212         case SSH_CHANNEL_LARVAL:
 213         case SSH_CHANNEL_CONNECTING:
 214         case SSH_CHANNEL_DYNAMIC:
 215         case SSH_CHANNEL_OPENING:
 216         case SSH_CHANNEL_OPEN:
 217         case SSH_CHANNEL_INPUT_DRAINING:
 218         case SSH_CHANNEL_OUTPUT_DRAINING:
 219                 return (c);
 220         }
 221         logit("Non-public channel %d, type %d.", id, c->type);
 222         return (NULL);
 223 }
 224
 225 /*
 226  * Register filedescriptors for a channel, used when allocating a channel or
 227  * when the channel consumer/producer is ready, e.g. shell exec'd
 228  */
 229 static void
 230 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
 231     int extusage, int nonblock, int is_tty)
 232 {
 233         /* Update the maximum file descriptor value. */
 234         channel_max_fd = MAX(channel_max_fd, rfd);
 235         channel_max_fd = MAX(channel_max_fd, wfd);
 236         channel_max_fd = MAX(channel_max_fd, efd);
 237
 238         if (rfd != -1)
 239                 fcntl(rfd, F_SETFD, FD_CLOEXEC);
 240         if (wfd != -1 && wfd != rfd)
 241                 fcntl(wfd, F_SETFD, FD_CLOEXEC);
 242         if (efd != -1 && efd != rfd && efd != wfd)
 243                 fcntl(efd, F_SETFD, FD_CLOEXEC);
 244
 245         c->rfd = rfd;
 246         c->wfd = wfd;
 247         c->sock = (rfd == wfd) ? rfd : -1;
 248         c->efd = efd;
 249         c->extended_usage = extusage;
 250
 251         if ((c->isatty = is_tty) != 0)
 252                 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
 253         c->wfd_isatty = is_tty || isatty(c->wfd);
 254
 255         /* enable nonblocking mode */
 256         if (nonblock) {
 257                 if (rfd != -1)
 258                         set_nonblock(rfd);
 259                 if (wfd != -1)
 260                         set_nonblock(wfd);
 261                 if (efd != -1)
 262                         set_nonblock(efd);
 263         }
 264 }
 265
 266 /*
 267  * Allocate a new channel object and set its type and socket. This will cause
 268  * remote_name to be freed.
 269  */
 270 Channel *
 271 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
 272     u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
 273 {
 274         int found;
 275         u_int i;
 276         Channel *c;
 277
 278         /* Do initial allocation if this is the first call. */
 279         if (channels_alloc == 0) {
 280                 channels_alloc = 10;
 281                 channels = xcalloc(channels_alloc, sizeof(Channel *));
 282                 for (i = 0; i < channels_alloc; i++)
 283                         channels[i] = NULL;
 284         }
 285         /* Try to find a free slot where to put the new channel. */
 286         for (found = -1, i = 0; i < channels_alloc; i++)
 287                 if (channels[i] == NULL) {
 288                         /* Found a free slot. */
 289                         found = (int)i;
 290                         break;
 291                 }
 292         if (found < 0) {
 293                 /* There are no free slots.  Take last+1 slot and expand the array.  */
 294                 found = channels_alloc;
 295                 if (channels_alloc > 10000)
 296                         fatal("channel_new: internal error: channels_alloc %d "
 297                             "too big.", channels_alloc);
 298                 channels = xrealloc(channels, channels_alloc + 10,
 299                     sizeof(Channel *));
 300                 channels_alloc += 10;
 301                 debug2("channel: expanding %d", channels_alloc);
 302                 for (i = found; i < channels_alloc; i++)
 303                         channels[i] = NULL;
 304         }
 305         /* Initialize and return new channel. */
 306         c = channels[found] = xcalloc(1, sizeof(Channel));
 307         buffer_init(&c->input);
 308         buffer_init(&c->output);
 309         buffer_init(&c->extended);
 310         c->path = NULL;
 311         c->ostate = CHAN_OUTPUT_OPEN;
 312         c->istate = CHAN_INPUT_OPEN;
 313         c->flags = 0;
 314         channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
 315         c->self = found;
 316         c->type = type;
 317         c->ctype = ctype;
 318         c->local_window = window;
 319         c->local_window_max = window;
 320         c->local_consumed = 0;
 321         c->local_maxpacket = maxpack;
 322         c->dynamic_window = 0;
 323         c->remote_id = -1;
 324         c->remote_name = xstrdup(remote_name);
 325         c->remote_window = 0;
 326         c->remote_maxpacket = 0;
 327         c->force_drain = 0;
 328         c->single_connection = 0;
 329         c->detach_user = NULL;
 330         c->detach_close = 0;
 331         c->open_confirm = NULL;
 332         c->open_confirm_ctx = NULL;
 333         c->input_filter = NULL;
 334         c->output_filter = NULL;
 335         c->filter_ctx = NULL;
 336         c->filter_cleanup = NULL;
 337         c->ctl_chan = -1;
 338         c->mux_rcb = NULL;
 339         c->mux_ctx = NULL;
 340         c->mux_pause = 0;
 341         c->delayed = 1;         /* prevent call to channel_post handler */
 342         TAILQ_INIT(&c->status_confirms);
 343         debug("channel %d: new [%s]", found, remote_name);
 344         return c;
 345 }
 346
 347 static int
 348 channel_find_maxfd(void)
 349 {
 350         u_int i;
 351         int max = 0;
 352         Channel *c;
 353
 354         for (i = 0; i < channels_alloc; i++) {
 355                 c = channels[i];
 356                 if (c != NULL) {
 357                         max = MAX(max, c->rfd);
 358                         max = MAX(max, c->wfd);
 359                         max = MAX(max, c->efd);
 360                 }
 361         }
 362         return max;
 363 }
 364
 365 int
 366 channel_close_fd(int *fdp)
 367 {
 368         int ret = 0, fd = *fdp;
 369
 370         if (fd != -1) {
 371                 ret = close(fd);
 372                 *fdp = -1;
 373                 if (fd == channel_max_fd)
 374                         channel_max_fd = channel_find_maxfd();
 375         }
 376         return ret;
 377 }
 378
 379 /* Close all channel fd/socket. */
 380 static void
 381 channel_close_fds(Channel *c)
 382 {
 383         channel_close_fd(&c->sock);
 384         channel_close_fd(&c->rfd);
 385         channel_close_fd(&c->wfd);
 386         channel_close_fd(&c->efd);
 387 }
 388
 389 /* Free the channel and close its fd/socket. */
 390 void
 391 channel_free(Channel *c)
 392 {
 393         char *s;
 394         u_int i, n;
 395         struct channel_confirm *cc;
 396
 397         for (n = 0, i = 0; i < channels_alloc; i++)
 398                 if (channels[i])
 399                         n++;
 400         debug("channel %d: free: %s, nchannels %u", c->self,
 401             c->remote_name ? c->remote_name : "???", n);
 402
 403         s = channel_open_message();
 404         debug3("channel %d: status: %s", c->self, s);
 405         xfree(s);
 406
 407         if (c->sock != -1)
 408                 shutdown(c->sock, SHUT_RDWR);
 409         channel_close_fds(c);
 410         buffer_free(&c->input);
 411         buffer_free(&c->output);
 412         buffer_free(&c->extended);
 413         if (c->remote_name) {
 414                 xfree(c->remote_name);
 415                 c->remote_name = NULL;
 416         }
 417         if (c->path) {
 418                 xfree(c->path);
 419                 c->path = NULL;
 420         }
 421         while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
 422                 if (cc->abandon_cb != NULL)
 423                         cc->abandon_cb(c, cc->ctx);
 424                 TAILQ_REMOVE(&c->status_confirms, cc, entry);
 425                 bzero(cc, sizeof(*cc));
 426                 xfree(cc);
 427         }
 428         if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
 429                 c->filter_cleanup(c->self, c->filter_ctx);
 430         channels[c->self] = NULL;
 431         xfree(c);
 432 }
 433
 434 void
 435 channel_free_all(void)
 436 {
 437         u_int i;
 438
 439         for (i = 0; i < channels_alloc; i++)
 440                 if (channels[i] != NULL)
 441                         channel_free(channels[i]);
 442 }
 443
 444 /*
 445  * Closes the sockets/fds of all channels.  This is used to close extra file
 446  * descriptors after a fork.
 447  */
 448 void
 449 channel_close_all(void)
 450 {
 451         u_int i;
 452
 453         for (i = 0; i < channels_alloc; i++)
 454                 if (channels[i] != NULL)
 455                         channel_close_fds(channels[i]);
 456 }
 457
 458 /*
 459  * Stop listening to channels.
 460  */
 461 void
 462 channel_stop_listening(void)
 463 {
 464         u_int i;
 465         Channel *c;
 466
 467         for (i = 0; i < channels_alloc; i++) {
 468                 c = channels[i];
 469                 if (c != NULL) {
 470                         switch (c->type) {
 471                         case SSH_CHANNEL_AUTH_SOCKET:
 472                         case SSH_CHANNEL_PORT_LISTENER:
 473                         case SSH_CHANNEL_RPORT_LISTENER:
 474                         case SSH_CHANNEL_X11_LISTENER:
 475                                 channel_close_fd(&c->sock);
 476                                 channel_free(c);
 477                                 break;
 478                         }
 479                 }
 480         }
 481 }
 482
 483 /*
 484  * Returns true if no channel has too much buffered data, and false if one or
 485  * more channel is overfull.
 486  */
 487 int
 488 channel_not_very_much_buffered_data(void)
 489 {
 490         u_int i;
 491         Channel *c;
 492
 493         for (i = 0; i < channels_alloc; i++) {
 494                 c = channels[i];
 495                 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
 496 #if 0
 497                         if (!compat20 &&
 498                             buffer_len(&c->input) > packet_get_maxsize()) {
 499                                 debug2("channel %d: big input buffer %d",
 500                                     c->self, buffer_len(&c->input));
 501                                 return 0;
 502                         }
 503 #endif
 504                         if (buffer_len(&c->output) > packet_get_maxsize()) {
 505                                 debug2("channel %d: big output buffer %u > %u",
 506                                     c->self, buffer_len(&c->output),
 507                                     packet_get_maxsize());
 508                                 return 0;
 509                         }
 510                 }
 511         }
 512         return 1;
 513 }
 514
 515 /* Returns true if any channel is still open. */
 516 int
 517 channel_still_open(void)
 518 {
 519         u_int i;
 520         Channel *c;
 521
 522         for (i = 0; i < channels_alloc; i++) {
 523                 c = channels[i];
 524                 if (c == NULL)
 525                         continue;
 526                 switch (c->type) {
 527                 case SSH_CHANNEL_X11_LISTENER:
 528                 case SSH_CHANNEL_PORT_LISTENER:
 529                 case SSH_CHANNEL_RPORT_LISTENER:
 530                 case SSH_CHANNEL_MUX_LISTENER:
 531                 case SSH_CHANNEL_CLOSED:
 532                 case SSH_CHANNEL_AUTH_SOCKET:
 533                 case SSH_CHANNEL_DYNAMIC:
 534                 case SSH_CHANNEL_CONNECTING:
 535                 case SSH_CHANNEL_ZOMBIE:
 536                         continue;
 537                 case SSH_CHANNEL_LARVAL:
 538                         if (!compat20)
 539                                 fatal("cannot happen: SSH_CHANNEL_LARVAL");
 540                         continue;
 541                 case SSH_CHANNEL_OPENING:
 542                 case SSH_CHANNEL_OPEN:
 543                 case SSH_CHANNEL_X11_OPEN:
 544                 case SSH_CHANNEL_MUX_CLIENT:
 545                         return 1;
 546                 case SSH_CHANNEL_INPUT_DRAINING:
 547                 case SSH_CHANNEL_OUTPUT_DRAINING:
 548                         if (!compat13)
 549                                 fatal("cannot happen: OUT_DRAIN");
 550                         return 1;
 551                 default:
 552                         fatal("channel_still_open: bad channel type %d", c->type);
 553                         /* NOTREACHED */
 554                 }
 555         }
 556         return 0;
 557 }
 558
 559 /* Returns the id of an open channel suitable for keepaliving */
 560 int
 561 channel_find_open(void)
 562 {
 563         u_int i;
 564         Channel *c;
 565
 566         for (i = 0; i < channels_alloc; i++) {
 567                 c = channels[i];
 568                 if (c == NULL || c->remote_id < 0)
 569                         continue;
 570                 switch (c->type) {
 571                 case SSH_CHANNEL_CLOSED:
 572                 case SSH_CHANNEL_DYNAMIC:
 573                 case SSH_CHANNEL_X11_LISTENER:
 574                 case SSH_CHANNEL_PORT_LISTENER:
 575                 case SSH_CHANNEL_RPORT_LISTENER:
 576                 case SSH_CHANNEL_MUX_LISTENER:
 577                 case SSH_CHANNEL_MUX_CLIENT:
 578                 case SSH_CHANNEL_OPENING:
 579                 case SSH_CHANNEL_CONNECTING:
 580                 case SSH_CHANNEL_ZOMBIE:
 581                         continue;
 582                 case SSH_CHANNEL_LARVAL:
 583                 case SSH_CHANNEL_AUTH_SOCKET:
 584                 case SSH_CHANNEL_OPEN:
 585                 case SSH_CHANNEL_X11_OPEN:
 586                         return i;
 587                 case SSH_CHANNEL_INPUT_DRAINING:
 588                 case SSH_CHANNEL_OUTPUT_DRAINING:
 589                         if (!compat13)
 590                                 fatal("cannot happen: OUT_DRAIN");
 591                         return i;
 592                 default:
 593                         fatal("channel_find_open: bad channel type %d", c->type);
 594                         /* NOTREACHED */
 595                 }
 596         }
 597         return -1;
 598 }
 599
 600
 601 /*
 602  * Returns a message describing the currently open forwarded connections,
 603  * suitable for sending to the client.  The message contains crlf pairs for
 604  * newlines.
 605  */
 606 char *
 607 channel_open_message(void)
 608 {
 609         Buffer buffer;
 610         Channel *c;
 611         char buf[1024], *cp;
 612         u_int i;
 613
 614         buffer_init(&buffer);
 615         snprintf(buf, sizeof buf, "The following connections are open:\r\n");
 616         buffer_append(&buffer, buf, strlen(buf));
 617         for (i = 0; i < channels_alloc; i++) {
 618                 c = channels[i];
 619                 if (c == NULL)
 620                         continue;
 621                 switch (c->type) {
 622                 case SSH_CHANNEL_X11_LISTENER:
 623                 case SSH_CHANNEL_PORT_LISTENER:
 624                 case SSH_CHANNEL_RPORT_LISTENER:
 625                 case SSH_CHANNEL_CLOSED:
 626                 case SSH_CHANNEL_AUTH_SOCKET:
 627                 case SSH_CHANNEL_ZOMBIE:
 628                 case SSH_CHANNEL_MUX_CLIENT:
 629                 case SSH_CHANNEL_MUX_LISTENER:
 630                         continue;
 631                 case SSH_CHANNEL_LARVAL:
 632                 case SSH_CHANNEL_OPENING:
 633                 case SSH_CHANNEL_CONNECTING:
 634                 case SSH_CHANNEL_DYNAMIC:
 635                 case SSH_CHANNEL_OPEN:
 636                 case SSH_CHANNEL_X11_OPEN:
 637                 case SSH_CHANNEL_INPUT_DRAINING:
 638                 case SSH_CHANNEL_OUTPUT_DRAINING:
 639                         snprintf(buf, sizeof buf,
 640                             "  #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cc %d)\r\n",
 641                             c->self, c->remote_name,
 642                             c->type, c->remote_id,
 643                             c->istate, buffer_len(&c->input),
 644                             c->ostate, buffer_len(&c->output),
 645                             c->rfd, c->wfd, c->ctl_chan);
 646                         buffer_append(&buffer, buf, strlen(buf));
 647                         continue;
 648                 default:
 649                         fatal("channel_open_message: bad channel type %d", c->type);
 650                         /* NOTREACHED */
 651                 }
 652         }
 653         buffer_append(&buffer, "\0", 1);
 654         cp = xstrdup(buffer_ptr(&buffer));
 655         buffer_free(&buffer);
 656         return cp;
 657 }
 658
 659 void
 660 channel_send_open(int id)
 661 {
 662         Channel *c = channel_lookup(id);
 663
 664         if (c == NULL) {
 665                 logit("channel_send_open: %d: bad id", id);
 666                 return;
 667         }
 668         debug2("channel %d: send open", id);
 669         packet_start(SSH2_MSG_CHANNEL_OPEN);
 670         packet_put_cstring(c->ctype);
 671         packet_put_int(c->self);
 672         packet_put_int(c->local_window);
 673         packet_put_int(c->local_maxpacket);
 674         packet_send();
 675 }
 676
 677 void
 678 channel_request_start(int id, char *service, int wantconfirm)
 679 {
 680         Channel *c = channel_lookup(id);
 681
 682         if (c == NULL) {
 683                 logit("channel_request_start: %d: unknown channel id", id);
 684                 return;
 685         }
 686         debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
 687         packet_start(SSH2_MSG_CHANNEL_REQUEST);
 688         packet_put_int(c->remote_id);
 689         packet_put_cstring(service);
 690         packet_put_char(wantconfirm);
 691 }
 692
 693 void
 694 channel_register_status_confirm(int id, channel_confirm_cb *cb,
 695     channel_confirm_abandon_cb *abandon_cb, void *ctx)
 696 {
 697         struct channel_confirm *cc;
 698         Channel *c;
 699
 700         if ((c = channel_lookup(id)) == NULL)
 701                 fatal("channel_register_expect: %d: bad id", id);
 702
 703         cc = xmalloc(sizeof(*cc));
 704         cc->cb = cb;
 705         cc->abandon_cb = abandon_cb;
 706         cc->ctx = ctx;
 707         TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
 708 }
 709
 710 void
 711 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
 712 {
 713         Channel *c = channel_lookup(id);
 714
 715         if (c == NULL) {
 716                 logit("channel_register_open_confirm: %d: bad id", id);
 717                 return;
 718         }
 719         c->open_confirm = fn;
 720         c->open_confirm_ctx = ctx;
 721 }
 722
 723 void
 724 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
 725 {
 726         Channel *c = channel_by_id(id);
 727
 728         if (c == NULL) {
 729                 logit("channel_register_cleanup: %d: bad id", id);
 730                 return;
 731         }
 732         c->detach_user = fn;
 733         c->detach_close = do_close;
 734 }
 735
 736 void
 737 channel_cancel_cleanup(int id)
 738 {
 739         Channel *c = channel_by_id(id);
 740
 741         if (c == NULL) {
 742                 logit("channel_cancel_cleanup: %d: bad id", id);
 743                 return;
 744         }
 745         c->detach_user = NULL;
 746         c->detach_close = 0;
 747 }
 748
 749 void
 750 channel_register_filter(int id, channel_infilter_fn *ifn,
 751     channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
 752 {
 753         Channel *c = channel_lookup(id);
 754
 755         if (c == NULL) {
 756                 logit("channel_register_filter: %d: bad id", id);
 757                 return;
 758         }
 759         c->input_filter = ifn;
 760         c->output_filter = ofn;
 761         c->filter_ctx = ctx;
 762         c->filter_cleanup = cfn;
 763 }
 764
 765 void
 766 channel_set_fds(int id, int rfd, int wfd, int efd,
 767     int extusage, int nonblock, int is_tty, u_int window_max)
 768 {
 769         Channel *c = channel_lookup(id);
 770
 771         if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
 772                 fatal("channel_activate for non-larval channel %d.", id);
 773         channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
 774         c->type = SSH_CHANNEL_OPEN;
 775         c->local_window = c->local_window_max = window_max;
 776         packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
 777         packet_put_int(c->remote_id);
 778         packet_put_int(c->local_window);
 779         packet_send();
 780 }
 781
 782 /*
 783  * 'channel_pre*' are called just before select() to add any bits relevant to
 784  * channels in the select bitmasks.
 785  */
 786 /*
 787  * 'channel_post*': perform any appropriate operations for channels which
 788  * have events pending.
 789  */
 790 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
 791 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
 792 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
 793
 794 /* ARGSUSED */
 795 static void
 796 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
 797 {
 798         FD_SET(c->sock, readset);
 799 }
 800
 801 /* ARGSUSED */
 802 static void
 803 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
 804 {
 805         debug3("channel %d: waiting for connection", c->self);
 806         FD_SET(c->sock, writeset);
 807 }
 808
 809 static void
 810 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
 811 {
 812         if (buffer_len(&c->input) < packet_get_maxsize())
 813                 FD_SET(c->sock, readset);
 814         if (buffer_len(&c->output) > 0)
 815                 FD_SET(c->sock, writeset);
 816 }
 817
 818 int channel_tcpwinsz () {
 819         u_int32_t tcpwinsz = 0;
 820         socklen_t optsz = sizeof(tcpwinsz);
 821         int ret = -1;
 822
 823         /* if we aren't on a socket return 128KB*/
 824         if(!packet_connection_is_on_socket())
 825             return(128*1024);
 826         ret = getsockopt(packet_get_connection_in(),
 827                          SOL_SOCKET, SO_RCVBUF, &tcpwinsz, &optsz);
 828         /* return no more than 64MB */
 829         if ((ret == 0) && tcpwinsz > BUFFER_MAX_LEN_HPN)
 830             tcpwinsz = BUFFER_MAX_LEN_HPN;
 831         debug2("tcpwinsz: %d for connection: %d", tcpwinsz,
 832                packet_get_connection_in());
 833         return(tcpwinsz);
 834 }
 835
 836 static void
 837 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
 838 {
 839         u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
 840
 841         /* check buffer limits */
 842         if ((!c->tcpwinsz) || (c->dynamic_window > 0))
 843             c->tcpwinsz = channel_tcpwinsz();
 844
 845         limit = MIN(limit, 2 * c->tcpwinsz);
 846
 847         if (c->istate == CHAN_INPUT_OPEN &&
 848             limit > 0 &&
 849             buffer_len(&c->input) < limit &&
 850             buffer_check_alloc(&c->input, CHAN_RBUF))
 851                 FD_SET(c->rfd, readset);
 852         if (c->ostate == CHAN_OUTPUT_OPEN ||
 853             c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
 854                 if (buffer_len(&c->output) > 0) {
 855                         FD_SET(c->wfd, writeset);
 856                 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
 857                         if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
 858                                 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
 859                                     c->self, c->efd, buffer_len(&c->extended));
 860                         else
 861                                 chan_obuf_empty(c);
 862                 }
 863         }
 864         /** XXX check close conditions, too */
 865         if (compat20 && c->efd != -1 &&
 866             !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
 867                 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
 868                     buffer_len(&c->extended) > 0)
 869                         FD_SET(c->efd, writeset);
 870                 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
 871                     (c->extended_usage == CHAN_EXTENDED_READ ||
 872                     c->extended_usage == CHAN_EXTENDED_IGNORE) &&
 873                     buffer_len(&c->extended) < c->remote_window)
 874                         FD_SET(c->efd, readset);
 875         }
 876         /* XXX: What about efd? races? */
 877 }
 878
 879 /* ARGSUSED */
 880 static void
 881 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
 882 {
 883         if (buffer_len(&c->input) == 0) {
 884                 packet_start(SSH_MSG_CHANNEL_CLOSE);
 885                 packet_put_int(c->remote_id);
 886                 packet_send();
 887                 c->type = SSH_CHANNEL_CLOSED;
 888                 debug2("channel %d: closing after input drain.", c->self);
 889         }
 890 }
 891
 892 /* ARGSUSED */
 893 static void
 894 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
 895 {
 896         if (buffer_len(&c->output) == 0)
 897                 chan_mark_dead(c);
 898         else
 899                 FD_SET(c->sock, writeset);
 900 }
 901
 902 /*
 903  * This is a special state for X11 authentication spoofing.  An opened X11
 904  * connection (when authentication spoofing is being done) remains in this
 905  * state until the first packet has been completely read.  The authentication
 906  * data in that packet is then substituted by the real data if it matches the
 907  * fake data, and the channel is put into normal mode.
 908  * XXX All this happens at the client side.
 909  * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
 910  */
 911 static int
 912 x11_open_helper(Buffer *b)
 913 {
 914         u_char *ucp;
 915         u_int proto_len, data_len;
 916
 917         /* Check if the fixed size part of the packet is in buffer. */
 918         if (buffer_len(b) < 12)
 919                 return 0;
 920
 921         /* Parse the lengths of variable-length fields. */
 922         ucp = buffer_ptr(b);
 923         if (ucp[0] == 0x42) {   /* Byte order MSB first. */
 924                 proto_len = 256 * ucp[6] + ucp[7];
 925                 data_len = 256 * ucp[8] + ucp[9];
 926         } else if (ucp[0] == 0x6c) {    /* Byte order LSB first. */
 927                 proto_len = ucp[6] + 256 * ucp[7];
 928                 data_len = ucp[8] + 256 * ucp[9];
 929         } else {
 930                 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
 931                     ucp[0]);
 932                 return -1;
 933         }
 934
 935         /* Check if the whole packet is in buffer. */
 936         if (buffer_len(b) <
 937             12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
 938                 return 0;
 939
 940         /* Check if authentication protocol matches. */
 941         if (proto_len != strlen(x11_saved_proto) ||
 942             memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
 943                 debug2("X11 connection uses different authentication protocol.");
 944                 return -1;
 945         }
 946         /* Check if authentication data matches our fake data. */
 947         if (data_len != x11_fake_data_len ||
 948             timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
 949                 x11_fake_data, x11_fake_data_len) != 0) {
 950                 debug2("X11 auth data does not match fake data.");
 951                 return -1;
 952         }
 953         /* Check fake data length */
 954         if (x11_fake_data_len != x11_saved_data_len) {
 955                 error("X11 fake_data_len %d != saved_data_len %d",
 956                     x11_fake_data_len, x11_saved_data_len);
 957                 return -1;
 958         }
 959         /*
 960          * Received authentication protocol and data match
 961          * our fake data. Substitute the fake data with real
 962          * data.
 963          */
 964         memcpy(ucp + 12 + ((proto_len + 3) & ~3),
 965             x11_saved_data, x11_saved_data_len);
 966         return 1;
 967 }
 968
 969 static void
 970 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
 971 {
 972         int ret = x11_open_helper(&c->output);
 973
 974         if (ret == 1) {
 975                 /* Start normal processing for the channel. */
 976                 c->type = SSH_CHANNEL_OPEN;
 977                 channel_pre_open_13(c, readset, writeset);
 978         } else if (ret == -1) {
 979                 /*
 980                  * We have received an X11 connection that has bad
 981                  * authentication information.
 982                  */
 983                 logit("X11 connection rejected because of wrong authentication.");
 984                 buffer_clear(&c->input);
 985                 buffer_clear(&c->output);
 986                 channel_close_fd(&c->sock);
 987                 c->sock = -1;
 988                 c->type = SSH_CHANNEL_CLOSED;
 989                 packet_start(SSH_MSG_CHANNEL_CLOSE);
 990                 packet_put_int(c->remote_id);
 991                 packet_send();
 992         }
 993 }
 994
 995 static void
 996 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
 997 {
 998         int ret = x11_open_helper(&c->output);
 999
1000         /* c->force_drain = 1; */
1001
1002         if (ret == 1) {
1003                 c->type = SSH_CHANNEL_OPEN;
1004                 channel_pre_open(c, readset, writeset);
1005         } else if (ret == -1) {
1006                 logit("X11 connection rejected because of wrong authentication.");
1007                 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
1008                 chan_read_failed(c);
1009                 buffer_clear(&c->input);
1010                 chan_ibuf_empty(c);
1011                 buffer_clear(&c->output);
1012                 /* for proto v1, the peer will send an IEOF */
1013                 if (compat20)
1014                         chan_write_failed(c);
1015                 else
1016                         c->type = SSH_CHANNEL_OPEN;
1017                 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
1018         }
1019 }
1020
1021 static void
1022 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1023 {
1024         if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
1025             buffer_check_alloc(&c->input, CHAN_RBUF))
1026                 FD_SET(c->rfd, readset);
1027         if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1028                 /* clear buffer immediately (discard any partial packet) */
1029                 buffer_clear(&c->input);
1030                 chan_ibuf_empty(c);
1031                 /* Start output drain. XXX just kill chan? */
1032                 chan_rcvd_oclose(c);
1033         }
1034         if (c->ostate == CHAN_OUTPUT_OPEN ||
1035             c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1036                 if (buffer_len(&c->output) > 0)
1037                         FD_SET(c->wfd, writeset);
1038                 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1039                         chan_obuf_empty(c);
1040         }
1041 }
1042
1043 /* try to decode a socks4 header */
1044 /* ARGSUSED */
1045 static int
1046 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1047 {
1048         char *p, *host;
1049         u_int len, have, i, found, need;
1050         char username[256];
1051         struct {
1052                 u_int8_t version;
1053                 u_int8_t command;
1054                 u_int16_t dest_port;
1055                 struct in_addr dest_addr;
1056         } s4_req, s4_rsp;
1057
1058         debug2("channel %d: decode socks4", c->self);
1059
1060         have = buffer_len(&c->input);
1061         len = sizeof(s4_req);
1062         if (have < len)
1063                 return 0;
1064         p = buffer_ptr(&c->input);
1065
1066         need = 1;
1067         /* SOCKS4A uses an invalid IP address 0.0.0.x */
1068         if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1069                 debug2("channel %d: socks4a request", c->self);
1070                 /* ... and needs an extra string (the hostname) */
1071                 need = 2;
1072         }
1073         /* Check for terminating NUL on the string(s) */
1074         for (found = 0, i = len; i < have; i++) {
1075                 if (p[i] == '\0') {
1076                         found++;
1077                         if (found == need)
1078                                 break;
1079                 }
1080                 if (i > 1024) {
1081                         /* the peer is probably sending garbage */
1082                         debug("channel %d: decode socks4: too long",
1083                             c->self);
1084                         return -1;
1085                 }
1086         }
1087         if (found < need)
1088                 return 0;
1089         buffer_get(&c->input, (char *)&s4_req.version, 1);
1090         buffer_get(&c->input, (char *)&s4_req.command, 1);
1091         buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1092         buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1093         have = buffer_len(&c->input);
1094         p = buffer_ptr(&c->input);
1095         len = strlen(p);
1096         debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1097         len++;                                  /* trailing '\0' */
1098         if (len > have)
1099                 fatal("channel %d: decode socks4: len %d > have %d",
1100                     c->self, len, have);
1101         strlcpy(username, p, sizeof(username));
1102         buffer_consume(&c->input, len);
1103
1104         if (c->path != NULL) {
1105                 xfree(c->path);
1106                 c->path = NULL;
1107         }
1108         if (need == 1) {                        /* SOCKS4: one string */
1109                 host = inet_ntoa(s4_req.dest_addr);
1110                 c->path = xstrdup(host);
1111         } else {                                /* SOCKS4A: two strings */
1112                 have = buffer_len(&c->input);
1113                 p = buffer_ptr(&c->input);
1114                 len = strlen(p);
1115                 debug2("channel %d: decode socks4a: host %s/%d",
1116                     c->self, p, len);
1117                 len++;                          /* trailing '\0' */
1118                 if (len > have)
1119                         fatal("channel %d: decode socks4a: len %d > have %d",
1120                             c->self, len, have);
1121                 if (len > NI_MAXHOST) {
1122                         error("channel %d: hostname \"%.100s\" too long",
1123                             c->self, p);
1124                         return -1;
1125                 }
1126                 c->path = xstrdup(p);
1127                 buffer_consume(&c->input, len);
1128         }
1129         c->host_port = ntohs(s4_req.dest_port);
1130
1131         debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1132             c->self, c->path, c->host_port, s4_req.command);
1133
1134         if (s4_req.command != 1) {
1135                 debug("channel %d: cannot handle: %s cn %d",
1136                     c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1137                 return -1;
1138         }
1139         s4_rsp.version = 0;                     /* vn: 0 for reply */
1140         s4_rsp.command = 90;                    /* cd: req granted */
1141         s4_rsp.dest_port = 0;                   /* ignored */
1142         s4_rsp.dest_addr.s_addr = INADDR_ANY;   /* ignored */
1143         buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1144         return 1;
1145 }
1146
1147 /* try to decode a socks5 header */
1148 #define SSH_SOCKS5_AUTHDONE     0x1000
1149 #define SSH_SOCKS5_NOAUTH       0x00
1150 #define SSH_SOCKS5_IPV4         0x01
1151 #define SSH_SOCKS5_DOMAIN       0x03
1152 #define SSH_SOCKS5_IPV6         0x04
1153 #define SSH_SOCKS5_CONNECT      0x01
1154 #define SSH_SOCKS5_SUCCESS      0x00
1155
1156 /* ARGSUSED */
1157 static int
1158 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1159 {
1160         struct {
1161                 u_int8_t version;
1162                 u_int8_t command;
1163                 u_int8_t reserved;
1164                 u_int8_t atyp;
1165         } s5_req, s5_rsp;
1166         u_int16_t dest_port;
1167         u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1168         u_int have, need, i, found, nmethods, addrlen, af;
1169
1170         debug2("channel %d: decode socks5", c->self);
1171         p = buffer_ptr(&c->input);
1172         if (p[0] != 0x05)
1173                 return -1;
1174         have = buffer_len(&c->input);
1175         if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1176                 /* format: ver | nmethods | methods */
1177                 if (have < 2)
1178                         return 0;
1179                 nmethods = p[1];
1180                 if (have < nmethods + 2)
1181                         return 0;
1182                 /* look for method: "NO AUTHENTICATION REQUIRED" */
1183                 for (found = 0, i = 2; i < nmethods + 2; i++) {
1184                         if (p[i] == SSH_SOCKS5_NOAUTH) {
1185                                 found = 1;
1186                                 break;
1187                         }
1188                 }
1189                 if (!found) {
1190                         debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1191                             c->self);
1192                         return -1;
1193                 }
1194                 buffer_consume(&c->input, nmethods + 2);
1195                 buffer_put_char(&c->output, 0x05);              /* version */
1196                 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1197                 FD_SET(c->sock, writeset);
1198                 c->flags |= SSH_SOCKS5_AUTHDONE;
1199                 debug2("channel %d: socks5 auth done", c->self);
1200                 return 0;                               /* need more */
1201         }
1202         debug2("channel %d: socks5 post auth", c->self);
1203         if (have < sizeof(s5_req)+1)
1204                 return 0;                       /* need more */
1205         memcpy(&s5_req, p, sizeof(s5_req));
1206         if (s5_req.version != 0x05 ||
1207             s5_req.command != SSH_SOCKS5_CONNECT ||
1208             s5_req.reserved != 0x00) {
1209                 debug2("channel %d: only socks5 connect supported", c->self);
1210                 return -1;
1211         }
1212         switch (s5_req.atyp){
1213         case SSH_SOCKS5_IPV4:
1214                 addrlen = 4;
1215                 af = AF_INET;
1216                 break;
1217         case SSH_SOCKS5_DOMAIN:
1218                 addrlen = p[sizeof(s5_req)];
1219                 af = -1;
1220                 break;
1221         case SSH_SOCKS5_IPV6:
1222                 addrlen = 16;
1223                 af = AF_INET6;
1224                 break;
1225         default:
1226                 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1227                 return -1;
1228         }
1229         need = sizeof(s5_req) + addrlen + 2;
1230         if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1231                 need++;
1232         if (have < need)
1233                 return 0;
1234         buffer_consume(&c->input, sizeof(s5_req));
1235         if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1236                 buffer_consume(&c->input, 1);    /* host string length */
1237         buffer_get(&c->input, (char *)&dest_addr, addrlen);
1238         buffer_get(&c->input, (char *)&dest_port, 2);
1239         dest_addr[addrlen] = '\0';
1240         if (c->path != NULL) {
1241                 xfree(c->path);
1242                 c->path = NULL;
1243         }
1244         if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1245                 if (addrlen >= NI_MAXHOST) {
1246                         error("channel %d: dynamic request: socks5 hostname "
1247                             "\"%.100s\" too long", c->self, dest_addr);
1248                         return -1;
1249                 }
1250                 c->path = xstrdup(dest_addr);
1251         } else {
1252                 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1253                         return -1;
1254                 c->path = xstrdup(ntop);
1255         }
1256         c->host_port = ntohs(dest_port);
1257
1258         debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1259             c->self, c->path, c->host_port, s5_req.command);
1260
1261         s5_rsp.version = 0x05;
1262         s5_rsp.command = SSH_SOCKS5_SUCCESS;
1263         s5_rsp.reserved = 0;                    /* ignored */
1264         s5_rsp.atyp = SSH_SOCKS5_IPV4;
1265         ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
1266         dest_port = 0;                          /* ignored */
1267
1268         buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1269         buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
1270         buffer_append(&c->output, &dest_port, sizeof(dest_port));
1271         return 1;
1272 }
1273
1274 Channel *
1275 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
1276     int in, int out)
1277 {
1278         Channel *c;
1279
1280         debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
1281             port_to_connect);
1282
1283         c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
1284             -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1285             0, "stdio-forward", /*nonblock*/0);
1286
1287         c->path = xstrdup(host_to_connect);
1288         c->host_port = port_to_connect;
1289         c->listening_port = 0;
1290         c->force_drain = 1;
1291
1292         channel_register_fds(c, in, out, -1, 0, 1, 0);
1293         port_open_helper(c, "direct-tcpip");
1294
1295         return c;
1296 }
1297
1298 /* dynamic port forwarding */
1299 static void
1300 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1301 {
1302         u_char *p;
1303         u_int have;
1304         int ret;
1305
1306         have = buffer_len(&c->input);
1307         debug2("channel %d: pre_dynamic: have %d", c->self, have);
1308         /* buffer_dump(&c->input); */
1309         /* check if the fixed size part of the packet is in buffer. */
1310         if (have < 3) {
1311                 /* need more */
1312                 FD_SET(c->sock, readset);
1313                 return;
1314         }
1315         /* try to guess the protocol */
1316         p = buffer_ptr(&c->input);
1317         switch (p[0]) {
1318         case 0x04:
1319                 ret = channel_decode_socks4(c, readset, writeset);
1320                 break;
1321         case 0x05:
1322                 ret = channel_decode_socks5(c, readset, writeset);
1323                 break;
1324         default:
1325                 ret = -1;
1326                 break;
1327         }
1328         if (ret < 0) {
1329                 chan_mark_dead(c);
1330         } else if (ret == 0) {
1331                 debug2("channel %d: pre_dynamic: need more", c->self);
1332                 /* need more */
1333                 FD_SET(c->sock, readset);
1334         } else {
1335                 /* switch to the next state */
1336                 c->type = SSH_CHANNEL_OPENING;
1337                 port_open_helper(c, "direct-tcpip");
1338         }
1339 }
1340
1341 /* This is our fake X11 server socket. */
1342 /* ARGSUSED */
1343 static void
1344 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1345 {
1346         Channel *nc;
1347         struct sockaddr_storage addr;
1348         int newsock;
1349         socklen_t addrlen;
1350         char buf[16384], *remote_ipaddr;
1351         int remote_port;
1352
1353         if (FD_ISSET(c->sock, readset)) {
1354                 debug("X11 connection requested.");
1355                 addrlen = sizeof(addr);
1356                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1357                 if (c->single_connection) {
1358                         debug2("single_connection: closing X11 listener.");
1359                         channel_close_fd(&c->sock);
1360                         chan_mark_dead(c);
1361                 }
1362                 if (newsock < 0) {
1363                         error("accept: %.100s", strerror(errno));
1364                         return;
1365                 }
1366                 set_nodelay(newsock);
1367                 remote_ipaddr = get_peer_ipaddr(newsock);
1368                 remote_port = get_peer_port(newsock);
1369                 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1370                     remote_ipaddr, remote_port);
1371
1372                 nc = channel_new("accepted x11 socket",
1373                     SSH_CHANNEL_OPENING, newsock, newsock, -1,
1374                     c->local_window_max, c->local_maxpacket, 0, buf, 1);
1375                 if (compat20) {
1376                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1377                         packet_put_cstring("x11");
1378                         packet_put_int(nc->self);
1379                         packet_put_int(nc->local_window_max);
1380                         packet_put_int(nc->local_maxpacket);
1381                         /* originator ipaddr and port */
1382                         packet_put_cstring(remote_ipaddr);
1383                         if (datafellows & SSH_BUG_X11FWD) {
1384                                 debug2("ssh2 x11 bug compat mode");
1385                         } else {
1386                                 packet_put_int(remote_port);
1387                         }
1388                         packet_send();
1389                 } else {
1390                         packet_start(SSH_SMSG_X11_OPEN);
1391                         packet_put_int(nc->self);
1392                         if (packet_get_protocol_flags() &
1393                             SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1394                                 packet_put_cstring(buf);
1395                         packet_send();
1396                 }
1397                 xfree(remote_ipaddr);
1398         }
1399 }
1400
1401 static void
1402 port_open_helper(Channel *c, char *rtype)
1403 {
1404         int direct;
1405         char buf[1024];
1406         char *remote_ipaddr = get_peer_ipaddr(c->sock);
1407         int remote_port = get_peer_port(c->sock);
1408
1409         if (remote_port == -1) {
1410                 /* Fake addr/port to appease peers that validate it (Tectia) */
1411                 xfree(remote_ipaddr);
1412                 remote_ipaddr = xstrdup("127.0.0.1");
1413                 remote_port = 65535;
1414         }
1415
1416         direct = (strcmp(rtype, "direct-tcpip") == 0);
1417
1418         snprintf(buf, sizeof buf,
1419             "%s: listening port %d for %.100s port %d, "
1420             "connect from %.200s port %d",
1421             rtype, c->listening_port, c->path, c->host_port,
1422             remote_ipaddr, remote_port);
1423
1424         xfree(c->remote_name);
1425         c->remote_name = xstrdup(buf);
1426
1427         if (compat20) {
1428                 packet_start(SSH2_MSG_CHANNEL_OPEN);
1429                 packet_put_cstring(rtype);
1430                 packet_put_int(c->self);
1431                 packet_put_int(c->local_window_max);
1432                 packet_put_int(c->local_maxpacket);
1433                 if (direct) {
1434                         /* target host, port */
1435                         packet_put_cstring(c->path);
1436                         packet_put_int(c->host_port);
1437                 } else {
1438                         /* listen address, port */
1439                         packet_put_cstring(c->path);
1440                         packet_put_int(c->listening_port);
1441                 }
1442                 /* originator host and port */
1443                 packet_put_cstring(remote_ipaddr);
1444                 packet_put_int((u_int)remote_port);
1445                 packet_send();
1446         } else {
1447                 packet_start(SSH_MSG_PORT_OPEN);
1448                 packet_put_int(c->self);
1449                 packet_put_cstring(c->path);
1450                 packet_put_int(c->host_port);
1451                 if (packet_get_protocol_flags() &
1452                     SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1453                         packet_put_cstring(c->remote_name);
1454                 packet_send();
1455         }
1456         xfree(remote_ipaddr);
1457 }
1458
1459 static void
1460 channel_set_reuseaddr(int fd)
1461 {
1462         int on = 1;
1463
1464         /*
1465          * Set socket options.
1466          * Allow local port reuse in TIME_WAIT.
1467          */
1468         if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1469                 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1470 }
1471
1472 /*
1473  * This socket is listening for connections to a forwarded TCP/IP port.
1474  */
1475 /* ARGSUSED */
1476 static void
1477 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1478 {
1479         Channel *nc;
1480         struct sockaddr_storage addr;
1481         int newsock, nextstate;
1482         socklen_t addrlen;
1483         char *rtype;
1484
1485         if (FD_ISSET(c->sock, readset)) {
1486                 debug("Connection to port %d forwarding "
1487                     "to %.100s port %d requested.",
1488                     c->listening_port, c->path, c->host_port);
1489
1490                 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1491                         nextstate = SSH_CHANNEL_OPENING;
1492                         rtype = "forwarded-tcpip";
1493                 } else {
1494                         if (c->host_port == 0) {
1495                                 nextstate = SSH_CHANNEL_DYNAMIC;
1496                                 rtype = "dynamic-tcpip";
1497                         } else {
1498                                 nextstate = SSH_CHANNEL_OPENING;
1499                                 rtype = "direct-tcpip";
1500                         }
1501                 }
1502
1503                 addrlen = sizeof(addr);
1504                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1505                 if (newsock < 0) {
1506                         error("accept: %.100s", strerror(errno));
1507                         return;
1508                 }
1509                 set_nodelay(newsock);
1510                 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1511                     c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1512                 nc->listening_port = c->listening_port;
1513                 nc->host_port = c->host_port;
1514                 if (c->path != NULL)
1515                         nc->path = xstrdup(c->path);
1516
1517                 if (nextstate != SSH_CHANNEL_DYNAMIC)
1518                         port_open_helper(nc, rtype);
1519         }
1520 }
1521
1522 /*
1523  * This is the authentication agent socket listening for connections from
1524  * clients.
1525  */
1526 /* ARGSUSED */
1527 static void
1528 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1529 {
1530         Channel *nc;
1531         int newsock;
1532         struct sockaddr_storage addr;
1533         socklen_t addrlen;
1534
1535         if (FD_ISSET(c->sock, readset)) {
1536                 addrlen = sizeof(addr);
1537                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1538                 if (newsock < 0) {
1539                         error("accept from auth socket: %.100s", strerror(errno));
1540                         return;
1541                 }
1542                 nc = channel_new("accepted auth socket",
1543                     SSH_CHANNEL_OPENING, newsock, newsock, -1,
1544                     c->local_window_max, c->local_maxpacket,
1545                     0, "accepted auth socket", 1);
1546                 if (compat20) {
1547                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1548                         packet_put_cstring("auth-agent@openssh.com");
1549                         packet_put_int(nc->self);
1550                         packet_put_int(c->local_window_max);
1551                         packet_put_int(c->local_maxpacket);
1552                 } else {
1553                         packet_start(SSH_SMSG_AGENT_OPEN);
1554                         packet_put_int(nc->self);
1555                 }
1556                 packet_send();
1557         }
1558 }
1559
1560 /* ARGSUSED */
1561 static void
1562 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1563 {
1564         int err = 0, sock;
1565         socklen_t sz = sizeof(err);
1566
1567         if (FD_ISSET(c->sock, writeset)) {
1568                 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1569                         err = errno;
1570                         error("getsockopt SO_ERROR failed");
1571                 }
1572                 if (err == 0) {
1573                         debug("channel %d: connected to %s port %d",
1574                             c->self, c->connect_ctx.host, c->connect_ctx.port);
1575                         channel_connect_ctx_free(&c->connect_ctx);
1576                         c->type = SSH_CHANNEL_OPEN;
1577                         if (compat20) {
1578                                 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1579                                 packet_put_int(c->remote_id);
1580                                 packet_put_int(c->self);
1581                                 packet_put_int(c->local_window);
1582                                 packet_put_int(c->local_maxpacket);
1583                         } else {
1584                                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1585                                 packet_put_int(c->remote_id);
1586                                 packet_put_int(c->self);
1587                         }
1588                 } else {
1589                         debug("channel %d: connection failed: %s",
1590                             c->self, strerror(err));
1591                         /* Try next address, if any */
1592                         if ((sock = connect_next(&c->connect_ctx)) > 0) {
1593                                 close(c->sock);
1594                                 c->sock = c->rfd = c->wfd = sock;
1595                                 channel_max_fd = channel_find_maxfd();
1596                                 return;
1597                         }
1598                         /* Exhausted all addresses */
1599                         error("connect_to %.100s port %d: failed.",
1600                             c->connect_ctx.host, c->connect_ctx.port);
1601                         channel_connect_ctx_free(&c->connect_ctx);
1602                         if (compat20) {
1603                                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1604                                 packet_put_int(c->remote_id);
1605                                 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1606                                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1607                                         packet_put_cstring(strerror(err));
1608                                         packet_put_cstring("");
1609                                 }
1610                         } else {
1611                                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1612                                 packet_put_int(c->remote_id);
1613                         }
1614                         chan_mark_dead(c);
1615                 }
1616                 packet_send();
1617         }
1618 }
1619
1620 /* ARGSUSED */
1621 static int
1622 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1623 {
1624         char buf[CHAN_RBUF];
1625         int len, force;
1626
1627         force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1628         if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1629                 errno = 0;
1630                 len = read(c->rfd, buf, sizeof(buf));
1631                 if (len < 0 && (errno == EINTR ||
1632                     ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1633                         return 1;
1634 #ifndef PTY_ZEROREAD
1635                 if (len <= 0) {
1636 #else
1637                 if ((!c->isatty && len <= 0) ||
1638                     (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1639 #endif
1640                         debug2("channel %d: read<=0 rfd %d len %d",
1641                             c->self, c->rfd, len);
1642                         if (c->type != SSH_CHANNEL_OPEN) {
1643                                 debug2("channel %d: not open", c->self);
1644                                 chan_mark_dead(c);
1645                                 return -1;
1646                         } else if (compat13) {
1647                                 buffer_clear(&c->output);
1648                                 c->type = SSH_CHANNEL_INPUT_DRAINING;
1649                                 debug2("channel %d: input draining.", c->self);
1650                         } else {
1651                                 chan_read_failed(c);
1652                         }
1653                         return -1;
1654                 }
1655                 if (c->input_filter != NULL) {
1656                         if (c->input_filter(c, buf, len) == -1) {
1657                                 debug2("channel %d: filter stops", c->self);
1658                                 chan_read_failed(c);
1659                         }
1660                 } else if (c->datagram) {
1661                         buffer_put_string(&c->input, buf, len);
1662                 } else {
1663                         buffer_append(&c->input, buf, len);
1664                 }
1665         }
1666         return 1;
1667 }
1668
1669 /* ARGSUSED */
1670 static int
1671 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1672 {
1673         struct termios tio;
1674         u_char *data = NULL, *buf;
1675         u_int dlen, olen = 0;
1676         int len;
1677
1678         /* Send buffered output data to the socket. */
1679         if (c->wfd != -1 &&
1680             FD_ISSET(c->wfd, writeset) &&
1681             buffer_len(&c->output) > 0) {
1682                 olen = buffer_len(&c->output);
1683                 if (c->output_filter != NULL) {
1684                         if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1685                                 debug2("channel %d: filter stops", c->self);
1686                                 if (c->type != SSH_CHANNEL_OPEN)
1687                                         chan_mark_dead(c);
1688                                 else
1689                                         chan_write_failed(c);
1690                                 return -1;
1691                         }
1692                 } else if (c->datagram) {
1693                         buf = data = buffer_get_string(&c->output, &dlen);
1694                 } else {
1695                         buf = data = buffer_ptr(&c->output);
1696                         dlen = buffer_len(&c->output);
1697                 }
1698
1699                 if (c->datagram) {
1700                         /* ignore truncated writes, datagrams might get lost */
1701                         len = write(c->wfd, buf, dlen);
1702                         xfree(data);
1703                         if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1704                             errno == EWOULDBLOCK))
1705                                 return 1;
1706                         if (len <= 0) {
1707                                 if (c->type != SSH_CHANNEL_OPEN)
1708                                         chan_mark_dead(c);
1709                                 else
1710                                         chan_write_failed(c);
1711                                 return -1;
1712                         }
1713                         goto out;
1714                 }
1715 #ifdef _AIX
1716                 /* XXX: Later AIX versions can't push as much data to tty */
1717                 if (compat20 && c->wfd_isatty)
1718                         dlen = MIN(dlen, 8*1024);
1719 #endif
1720
1721                 len = write(c->wfd, buf, dlen);
1722                 if (len < 0 &&
1723                     (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1724                         return 1;
1725                 if (len <= 0) {
1726                         if (c->type != SSH_CHANNEL_OPEN) {
1727                                 debug2("channel %d: not open", c->self);
1728                                 chan_mark_dead(c);
1729                                 return -1;
1730                         } else if (compat13) {
1731                                 buffer_clear(&c->output);
1732                                 debug2("channel %d: input draining.", c->self);
1733                                 c->type = SSH_CHANNEL_INPUT_DRAINING;
1734                         } else {
1735                                 chan_write_failed(c);
1736                         }
1737                         return -1;
1738                 }
1739 #ifndef BROKEN_TCGETATTR_ICANON
1740                 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1741                         if (tcgetattr(c->wfd, &tio) == 0 &&
1742                             !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1743                                 /*
1744                                  * Simulate echo to reduce the impact of
1745                                  * traffic analysis. We need to match the
1746                                  * size of a SSH2_MSG_CHANNEL_DATA message
1747                                  * (4 byte channel id + buf)
1748                                  */
1749                                 packet_send_ignore(4 + len);
1750                                 packet_send();
1751                         }
1752                 }
1753 #endif
1754                 buffer_consume(&c->output, len);
1755         }
1756  out:
1757         if (compat20 && olen > 0)
1758                 c->local_consumed += olen - buffer_len(&c->output);
1759         return 1;
1760 }
1761
1762 static int
1763 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1764 {
1765         char buf[CHAN_RBUF];
1766         int len;
1767
1768 /** XXX handle drain efd, too */
1769         if (c->efd != -1) {
1770                 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1771                     FD_ISSET(c->efd, writeset) &&
1772                     buffer_len(&c->extended) > 0) {
1773                         len = write(c->efd, buffer_ptr(&c->extended),
1774                             buffer_len(&c->extended));
1775                         debug2("channel %d: written %d to efd %d",
1776                             c->self, len, c->efd);
1777                         if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1778                             errno == EWOULDBLOCK))
1779                                 return 1;
1780                         if (len <= 0) {
1781                                 debug2("channel %d: closing write-efd %d",
1782                                     c->self, c->efd);
1783                                 channel_close_fd(&c->efd);
1784                         } else {
1785                                 buffer_consume(&c->extended, len);
1786                                 c->local_consumed += len;
1787                         }
1788                 } else if (c->efd != -1 &&
1789                     (c->extended_usage == CHAN_EXTENDED_READ ||
1790                     c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1791                     (c->detach_close || FD_ISSET(c->efd, readset))) {
1792                         len = read(c->efd, buf, sizeof(buf));
1793                         debug2("channel %d: read %d from efd %d",
1794                             c->self, len, c->efd);
1795                         if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1796                             errno == EWOULDBLOCK) && !c->detach_close)))
1797                                 return 1;
1798                         if (len <= 0) {
1799                                 debug2("channel %d: closing read-efd %d",
1800                                     c->self, c->efd);
1801                                 channel_close_fd(&c->efd);
1802                         } else {
1803                                 if (c->extended_usage == CHAN_EXTENDED_IGNORE) {
1804                                         debug3("channel %d: discard efd",
1805                                             c->self);
1806                                 } else
1807                                         buffer_append(&c->extended, buf, len);
1808                         }
1809                 }
1810         }
1811         return 1;
1812 }
1813
1814 static int
1815 channel_check_window(Channel *c)
1816 {
1817         if (c->type == SSH_CHANNEL_OPEN &&
1818             !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1819             ((c->local_window_max - c->local_window >
1820             c->local_maxpacket*3) ||
1821             c->local_window < c->local_window_max/2) &&
1822             c->local_consumed > 0) {
1823                 u_int addition = 0;
1824                 /* adjust max window size if we are in a dynamic environment */
1825                 if (c->dynamic_window && (c->tcpwinsz > c->local_window_max)) {
1826                         /* grow the window somewhat aggressively to maintain pressure */
1827                         addition = 1.5*(c->tcpwinsz - c->local_window_max);
1828                         c->local_window_max += addition;
1829                 }
1830                 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1831                 packet_put_int(c->remote_id);
1832                 packet_put_int(c->local_consumed + addition);
1833                 packet_send();
1834                 debug2("channel %d: window %d sent adjust %d",
1835                     c->self, c->local_window,
1836                     c->local_consumed);
1837                 c->local_window += c->local_consumed + addition;
1838                 c->local_consumed = 0;
1839         }
1840         return 1;
1841 }
1842
1843 static void
1844 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1845 {
1846         channel_handle_rfd(c, readset, writeset);
1847         channel_handle_wfd(c, readset, writeset);
1848         if (!compat20)
1849                 return;
1850         channel_handle_efd(c, readset, writeset);
1851         channel_check_window(c);
1852 }
1853
1854 static u_int
1855 read_mux(Channel *c, u_int need)
1856 {
1857         char buf[CHAN_RBUF];
1858         int len;
1859         u_int rlen;
1860
1861         if (buffer_len(&c->input) < need) {
1862                 rlen = need - buffer_len(&c->input);
1863                 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF));
1864                 if (len <= 0) {
1865                         if (errno != EINTR && errno != EAGAIN) {
1866                                 debug2("channel %d: ctl read<=0 rfd %d len %d",
1867                                     c->self, c->rfd, len);
1868                                 chan_read_failed(c);
1869                                 return 0;
1870                         }
1871                 } else
1872                         buffer_append(&c->input, buf, len);
1873         }
1874         return buffer_len(&c->input);
1875 }
1876
1877 static void
1878 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1879 {
1880         u_int need;
1881         ssize_t len;
1882
1883         if (!compat20)
1884                 fatal("%s: entered with !compat20", __func__);
1885
1886         if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
1887             (c->istate == CHAN_INPUT_OPEN ||
1888             c->istate == CHAN_INPUT_WAIT_DRAIN)) {
1889                 /*
1890                  * Don't not read past the precise end of packets to
1891                  * avoid disrupting fd passing.
1892                  */
1893                 if (read_mux(c, 4) < 4) /* read header */
1894                         return;
1895                 need = get_u32(buffer_ptr(&c->input));
1896 #define CHANNEL_MUX_MAX_PACKET  (256 * 1024)
1897                 if (need > CHANNEL_MUX_MAX_PACKET) {
1898                         debug2("channel %d: packet too big %u > %u",
1899                             c->self, CHANNEL_MUX_MAX_PACKET, need);
1900                         chan_rcvd_oclose(c);
1901                         return;
1902                 }
1903                 if (read_mux(c, need + 4) < need + 4) /* read body */
1904                         return;
1905                 if (c->mux_rcb(c) != 0) {
1906                         debug("channel %d: mux_rcb failed", c->self);
1907                         chan_mark_dead(c);
1908                         return;
1909                 }
1910         }
1911
1912         if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) &&
1913             buffer_len(&c->output) > 0) {
1914                 len = write(c->wfd, buffer_ptr(&c->output),
1915                     buffer_len(&c->output));
1916                 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1917                         return;
1918                 if (len <= 0) {
1919                         chan_mark_dead(c);
1920                         return;
1921                 }
1922                 buffer_consume(&c->output, len);
1923         }
1924 }
1925
1926 static void
1927 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset)
1928 {
1929         Channel *nc;
1930         struct sockaddr_storage addr;
1931         socklen_t addrlen;
1932         int newsock;
1933         uid_t euid;
1934         gid_t egid;
1935
1936         if (!FD_ISSET(c->sock, readset))
1937                 return;
1938
1939         debug("multiplexing control connection");
1940
1941         /*
1942          * Accept connection on control socket
1943          */
1944         memset(&addr, 0, sizeof(addr));
1945         addrlen = sizeof(addr);
1946         if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
1947             &addrlen)) == -1) {
1948                 error("%s accept: %s", __func__, strerror(errno));
1949                 return;
1950         }
1951
1952         if (getpeereid(newsock, &euid, &egid) < 0) {
1953                 error("%s getpeereid failed: %s", __func__,
1954                     strerror(errno));
1955                 close(newsock);
1956                 return;
1957         }
1958         if ((euid != 0) && (getuid() != euid)) {
1959                 error("multiplex uid mismatch: peer euid %u != uid %u",
1960                     (u_int)euid, (u_int)getuid());
1961                 close(newsock);
1962                 return;
1963         }
1964         nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT,
1965             newsock, newsock, -1, c->local_window_max,
1966             c->local_maxpacket, 0, "mux-control", 1);
1967         nc->mux_rcb = c->mux_rcb;
1968         debug3("%s: new mux channel %d fd %d", __func__,
1969             nc->self, nc->sock);
1970         /* establish state */
1971         nc->mux_rcb(nc);
1972         /* mux state transitions must not elicit protocol messages */
1973         nc->flags |= CHAN_LOCAL;
1974 }
1975
1976 /* ARGSUSED */
1977 static void
1978 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
1979 {
1980         int len;
1981
1982         /* Send buffered output data to the socket. */
1983         if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
1984                 len = write(c->sock, buffer_ptr(&c->output),
1985                             buffer_len(&c->output));
1986                 if (len <= 0)
1987                         buffer_clear(&c->output);
1988                 else
1989                         buffer_consume(&c->output, len);
1990         }
1991 }
1992
1993 static void
1994 channel_handler_init_20(void)
1995 {
1996         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open;
1997         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open;
1998         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
1999         channel_pre[SSH_CHANNEL_RPORT_LISTENER] =       &channel_pre_listener;
2000         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
2001         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
2002         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
2003         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
2004         channel_pre[SSH_CHANNEL_MUX_LISTENER] =         &channel_pre_listener;
2005         channel_pre[SSH_CHANNEL_MUX_CLIENT] =           &channel_pre_mux_client;
2006
2007         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
2008         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
2009         channel_post[SSH_CHANNEL_RPORT_LISTENER] =      &channel_post_port_listener;
2010         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
2011         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
2012         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
2013         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
2014         channel_post[SSH_CHANNEL_MUX_LISTENER] =        &channel_post_mux_listener;
2015         channel_post[SSH_CHANNEL_MUX_CLIENT] =          &channel_post_mux_client;
2016 }
2017
2018 static void
2019 channel_handler_init_13(void)
2020 {
2021         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open_13;
2022         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open_13;
2023         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
2024         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
2025         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
2026         channel_pre[SSH_CHANNEL_INPUT_DRAINING] =       &channel_pre_input_draining;
2027         channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] =      &channel_pre_output_draining;
2028         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
2029         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
2030
2031         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
2032         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
2033         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
2034         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
2035         channel_post[SSH_CHANNEL_OUTPUT_DRAINING] =     &channel_post_output_drain_13;
2036         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
2037         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
2038 }
2039
2040 static void
2041 channel_handler_init_15(void)
2042 {
2043         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open;
2044         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open;
2045         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
2046         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
2047         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
2048         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
2049         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
2050
2051         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
2052         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
2053         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
2054         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
2055         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
2056         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
2057 }
2058
2059 static void
2060 channel_handler_init(void)
2061 {
2062         int i;
2063
2064         for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
2065                 channel_pre[i] = NULL;
2066                 channel_post[i] = NULL;
2067         }
2068         if (compat20)
2069                 channel_handler_init_20();
2070         else if (compat13)
2071                 channel_handler_init_13();
2072         else
2073                 channel_handler_init_15();
2074 }
2075
2076 /* gc dead channels */
2077 static void
2078 channel_garbage_collect(Channel *c)
2079 {
2080         if (c == NULL)
2081                 return;
2082         if (c->detach_user != NULL) {
2083                 if (!chan_is_dead(c, c->detach_close))
2084                         return;
2085                 debug2("channel %d: gc: notify user", c->self);
2086                 c->detach_user(c->self, NULL);
2087                 /* if we still have a callback */
2088                 if (c->detach_user != NULL)
2089                         return;
2090                 debug2("channel %d: gc: user detached", c->self);
2091         }
2092         if (!chan_is_dead(c, 1))
2093                 return;
2094         debug2("channel %d: garbage collecting", c->self);
2095         channel_free(c);
2096 }
2097
2098 static void
2099 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset)
2100 {
2101         static int did_init = 0;
2102         u_int i, oalloc;
2103         Channel *c;
2104
2105         if (!did_init) {
2106                 channel_handler_init();
2107                 did_init = 1;
2108         }
2109         for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
2110                 c = channels[i];
2111                 if (c == NULL)
2112                         continue;
2113                 if (c->delayed) {
2114                         if (ftab == channel_pre)
2115                                 c->delayed = 0;
2116                         else
2117                                 continue;
2118                 }
2119                 if (ftab[c->type] != NULL)
2120                         (*ftab[c->type])(c, readset, writeset);
2121                 channel_garbage_collect(c);
2122         }
2123 }
2124
2125 /*
2126  * Allocate/update select bitmasks and add any bits relevant to channels in
2127  * select bitmasks.
2128  */
2129 void
2130 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
2131     u_int *nallocp, int rekeying)
2132 {
2133         u_int n, sz, nfdset;
2134
2135         n = MAX(*maxfdp, channel_max_fd);
2136
2137         nfdset = howmany(n+1, NFDBITS);
2138         /* Explicitly test here, because xrealloc isn't always called */
2139         if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
2140                 fatal("channel_prepare_select: max_fd (%d) is too large", n);
2141         sz = nfdset * sizeof(fd_mask);
2142
2143         /* perhaps check sz < nalloc/2 and shrink? */
2144         if (*readsetp == NULL || sz > *nallocp) {
2145                 *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
2146                 *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
2147                 *nallocp = sz;
2148         }
2149         *maxfdp = n;
2150         memset(*readsetp, 0, sz);
2151         memset(*writesetp, 0, sz);
2152
2153         if (!rekeying)
2154                 channel_handler(channel_pre, *readsetp, *writesetp);
2155 }
2156
2157 /*
2158  * After select, perform any appropriate operations for channels which have
2159  * events pending.
2160  */
2161 void
2162 channel_after_select(fd_set *readset, fd_set *writeset)
2163 {
2164         channel_handler(channel_post, readset, writeset);
2165 }
2166
2167
2168 /* If there is data to send to the connection, enqueue some of it now. */
2169 int
2170 channel_output_poll(void)
2171 {
2172         Channel *c;
2173         u_int i, len;
2174         int packet_length = 0;
2175
2176         for (i = 0; i < channels_alloc; i++) {
2177                 c = channels[i];
2178                 if (c == NULL)
2179                         continue;
2180
2181                 /*
2182                  * We are only interested in channels that can have buffered
2183                  * incoming data.
2184                  */
2185                 if (compat13) {
2186                         if (c->type != SSH_CHANNEL_OPEN &&
2187                             c->type != SSH_CHANNEL_INPUT_DRAINING)
2188                                 continue;
2189                 } else {
2190                         if (c->type != SSH_CHANNEL_OPEN)
2191                                 continue;
2192                 }
2193                 if (compat20 &&
2194                     (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2195                         /* XXX is this true? */
2196                         debug3("channel %d: will not send data after close", c->self);
2197                         continue;
2198                 }
2199
2200                 /* Get the amount of buffered data for this channel. */
2201                 if ((c->istate == CHAN_INPUT_OPEN ||
2202                     c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2203                     (len = buffer_len(&c->input)) > 0) {
2204                         if (c->datagram) {
2205                                 if (len > 0) {
2206                                         u_char *data;
2207                                         u_int dlen;
2208
2209                                         data = buffer_get_string(&c->input,
2210                                             &dlen);
2211                                         if (dlen > c->remote_window ||
2212                                             dlen > c->remote_maxpacket) {
2213                                                 debug("channel %d: datagram "
2214                                                     "too big for channel",
2215                                                     c->self);
2216                                                 xfree(data);
2217                                                 continue;
2218                                         }
2219                                         packet_start(SSH2_MSG_CHANNEL_DATA);
2220                                         packet_put_int(c->remote_id);
2221                                         packet_put_string(data, dlen);
2222                                         packet_length = packet_send();
2223                                         c->remote_window -= dlen + 4;
2224                                         xfree(data);
2225                                 }
2226                                 continue;
2227                         }
2228                         /*
2229                          * Send some data for the other side over the secure
2230                          * connection.
2231                          */
2232                         if (compat20) {
2233                                 if (len > c->remote_window)
2234                                         len = c->remote_window;
2235                                 if (len > c->remote_maxpacket)
2236                                         len = c->remote_maxpacket;
2237                         } else {
2238                                 if (packet_is_interactive()) {
2239                                         if (len > 1024)
2240                                                 len = 512;
2241                                 } else {
2242                                         /* Keep the packets at reasonable size. */
2243                                         if (len > packet_get_maxsize()/2)
2244                                                 len = packet_get_maxsize()/2;
2245                                 }
2246                         }
2247                         if (len > 0) {
2248                                 packet_start(compat20 ?
2249                                     SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2250                                 packet_put_int(c->remote_id);
2251                                 packet_put_string(buffer_ptr(&c->input), len);
2252                                 packet_length = packet_send();
2253                                 buffer_consume(&c->input, len);
2254                                 c->remote_window -= len;
2255                         }
2256                 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2257                         if (compat13)
2258                                 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2259                         /*
2260                          * input-buffer is empty and read-socket shutdown:
2261                          * tell peer, that we will not send more data: send IEOF.
2262                          * hack for extended data: delay EOF if EFD still in use.
2263                          */
2264                         if (CHANNEL_EFD_INPUT_ACTIVE(c))
2265                                 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2266                                     c->self, c->efd, buffer_len(&c->extended));
2267                         else
2268                                 chan_ibuf_empty(c);
2269                 }
2270                 /* Send extended data, i.e. stderr */
2271                 if (compat20 &&
2272                     !(c->flags & CHAN_EOF_SENT) &&
2273                     c->remote_window > 0 &&
2274                     (len = buffer_len(&c->extended)) > 0 &&
2275                     c->extended_usage == CHAN_EXTENDED_READ) {
2276                         debug2("channel %d: rwin %u elen %u euse %d",
2277                             c->self, c->remote_window, buffer_len(&c->extended),
2278                             c->extended_usage);
2279                         if (len > c->remote_window)
2280                                 len = c->remote_window;
2281                         if (len > c->remote_maxpacket)
2282                                 len = c->remote_maxpacket;
2283                         packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2284                         packet_put_int(c->remote_id);
2285                         packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2286                         packet_put_string(buffer_ptr(&c->extended), len);
2287                         packet_length = packet_send();
2288                         buffer_consume(&c->extended, len);
2289                         c->remote_window -= len;
2290                         debug2("channel %d: sent ext data %d", c->self, len);
2291                 }
2292         }
2293         return (packet_length);
2294 }
2295
2296
2297 /* -- protocol input */
2298
2299 /* ARGSUSED */
2300 void
2301 channel_input_data(int type, u_int32_t seq, void *ctxt)
2302 {
2303         int id;
2304         char *data;
2305         u_int data_len, win_len;
2306         Channel *c;
2307
2308         /* Get the channel number and verify it. */
2309         id = packet_get_int();
2310         c = channel_lookup(id);
2311         if (c == NULL)
2312                 packet_disconnect("Received data for nonexistent channel %d.", id);
2313
2314         /* Ignore any data for non-open channels (might happen on close) */
2315         if (c->type != SSH_CHANNEL_OPEN &&
2316             c->type != SSH_CHANNEL_X11_OPEN)
2317                 return;
2318
2319         /* Get the data. */
2320         data = packet_get_string_ptr(&data_len);
2321         win_len = data_len;
2322         if (c->datagram)
2323                 win_len += 4;  /* string length header */
2324
2325         /*
2326          * Ignore data for protocol > 1.3 if output end is no longer open.
2327          * For protocol 2 the sending side is reducing its window as it sends
2328          * data, so we must 'fake' consumption of the data in order to ensure
2329          * that window updates are sent back.  Otherwise the connection might
2330          * deadlock.
2331          */
2332         if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2333                 if (compat20) {
2334                         c->local_window -= win_len;
2335                         c->local_consumed += win_len;
2336                 }
2337                 return;
2338         }
2339
2340         if (compat20) {
2341                 if (win_len > c->local_maxpacket) {
2342                         logit("channel %d: rcvd big packet %d, maxpack %d",
2343                             c->self, win_len, c->local_maxpacket);
2344                 }
2345                 if (win_len > c->local_window) {
2346                         logit("channel %d: rcvd too much data %d, win %d",
2347                             c->self, win_len, c->local_window);
2348                         return;
2349                 }
2350                 c->local_window -= win_len;
2351         }
2352         if (c->datagram)
2353                 buffer_put_string(&c->output, data, data_len);
2354         else
2355                 buffer_append(&c->output, data, data_len);
2356         packet_check_eom();
2357 }
2358
2359 /* ARGSUSED */
2360 void
2361 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2362 {
2363         int id;
2364         char *data;
2365         u_int data_len, tcode;
2366         Channel *c;
2367
2368         /* Get the channel number and verify it. */
2369         id = packet_get_int();
2370         c = channel_lookup(id);
2371
2372         if (c == NULL)
2373                 packet_disconnect("Received extended_data for bad channel %d.", id);
2374         if (c->type != SSH_CHANNEL_OPEN) {
2375                 logit("channel %d: ext data for non open", id);
2376                 return;
2377         }
2378         if (c->flags & CHAN_EOF_RCVD) {
2379                 if (datafellows & SSH_BUG_EXTEOF)
2380                         debug("channel %d: accepting ext data after eof", id);
2381                 else
2382                         packet_disconnect("Received extended_data after EOF "
2383                             "on channel %d.", id);
2384         }
2385         tcode = packet_get_int();
2386         if (c->efd == -1 ||
2387             c->extended_usage != CHAN_EXTENDED_WRITE ||
2388             tcode != SSH2_EXTENDED_DATA_STDERR) {
2389                 logit("channel %d: bad ext data", c->self);
2390                 return;
2391         }
2392         data = packet_get_string(&data_len);
2393         packet_check_eom();
2394         if (data_len > c->local_window) {
2395                 logit("channel %d: rcvd too much extended_data %d, win %d",
2396                     c->self, data_len, c->local_window);
2397                 xfree(data);
2398                 return;
2399         }
2400         debug2("channel %d: rcvd ext data %d", c->self, data_len);
2401         c->local_window -= data_len;
2402         buffer_append(&c->extended, data, data_len);
2403         xfree(data);
2404 }
2405
2406 /* ARGSUSED */
2407 void
2408 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2409 {
2410         int id;
2411         Channel *c;
2412
2413         id = packet_get_int();
2414         packet_check_eom();
2415         c = channel_lookup(id);
2416         if (c == NULL)
2417                 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2418         chan_rcvd_ieof(c);
2419
2420         /* XXX force input close */
2421         if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2422                 debug("channel %d: FORCE input drain", c->self);
2423                 c->istate = CHAN_INPUT_WAIT_DRAIN;
2424                 if (buffer_len(&c->input) == 0)
2425                         chan_ibuf_empty(c);
2426         }
2427
2428 }
2429
2430 /* ARGSUSED */
2431 void
2432 channel_input_close(int type, u_int32_t seq, void *ctxt)
2433 {
2434         int id;
2435         Channel *c;
2436
2437         id = packet_get_int();
2438         packet_check_eom();
2439         c = channel_lookup(id);
2440         if (c == NULL)
2441                 packet_disconnect("Received close for nonexistent channel %d.", id);
2442
2443         /*
2444          * Send a confirmation that we have closed the channel and no more
2445          * data is coming for it.
2446          */
2447         packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2448         packet_put_int(c->remote_id);
2449         packet_send();
2450
2451         /*
2452          * If the channel is in closed state, we have sent a close request,
2453          * and the other side will eventually respond with a confirmation.
2454          * Thus, we cannot free the channel here, because then there would be
2455          * no-one to receive the confirmation.  The channel gets freed when
2456          * the confirmation arrives.
2457          */
2458         if (c->type != SSH_CHANNEL_CLOSED) {
2459                 /*
2460                  * Not a closed channel - mark it as draining, which will
2461                  * cause it to be freed later.
2462                  */
2463                 buffer_clear(&c->input);
2464                 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2465         }
2466 }
2467
2468 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2469 /* ARGSUSED */
2470 void
2471 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2472 {
2473         int id = packet_get_int();
2474         Channel *c = channel_lookup(id);
2475
2476         packet_check_eom();
2477         if (c == NULL)
2478                 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2479         chan_rcvd_oclose(c);
2480 }
2481
2482 /* ARGSUSED */
2483 void
2484 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2485 {
2486         int id = packet_get_int();
2487         Channel *c = channel_lookup(id);
2488
2489         packet_check_eom();
2490         if (c == NULL)
2491                 packet_disconnect("Received close confirmation for "
2492                     "out-of-range channel %d.", id);
2493         if (c->type != SSH_CHANNEL_CLOSED)
2494                 packet_disconnect("Received close confirmation for "
2495                     "non-closed channel %d (type %d).", id, c->type);
2496         channel_free(c);
2497 }
2498
2499 /* ARGSUSED */
2500 void
2501 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2502 {
2503         int id, remote_id;
2504         Channel *c;
2505
2506         id = packet_get_int();
2507         c = channel_lookup(id);
2508
2509         if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2510                 packet_disconnect("Received open confirmation for "
2511                     "non-opening channel %d.", id);
2512         remote_id = packet_get_int();
2513         /* Record the remote channel number and mark that the channel is now open. */
2514         c->remote_id = remote_id;
2515         c->type = SSH_CHANNEL_OPEN;
2516
2517         if (compat20) {
2518                 c->remote_window = packet_get_int();
2519                 c->remote_maxpacket = packet_get_int();
2520                 if (c->open_confirm) {
2521                         debug2("callback start");
2522                         c->open_confirm(c->self, 1, c->open_confirm_ctx);
2523                         debug2("callback done");
2524                 }
2525                 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2526                     c->remote_window, c->remote_maxpacket);
2527         }
2528         packet_check_eom();
2529 }
2530
2531 static char *
2532 reason2txt(int reason)
2533 {
2534         switch (reason) {
2535         case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2536                 return "administratively prohibited";
2537         case SSH2_OPEN_CONNECT_FAILED:
2538                 return "connect failed";
2539         case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2540                 return "unknown channel type";
2541         case SSH2_OPEN_RESOURCE_SHORTAGE:
2542                 return "resource shortage";
2543         }
2544         return "unknown reason";
2545 }
2546
2547 /* ARGSUSED */
2548 void
2549 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2550 {
2551         int id, reason;
2552         char *msg = NULL, *lang = NULL;
2553         Channel *c;
2554
2555         id = packet_get_int();
2556         c = channel_lookup(id);
2557
2558         if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2559                 packet_disconnect("Received open failure for "
2560                     "non-opening channel %d.", id);
2561         if (compat20) {
2562                 reason = packet_get_int();
2563                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2564                         msg  = packet_get_string(NULL);
2565                         lang = packet_get_string(NULL);
2566                 }
2567                 logit("channel %d: open failed: %s%s%s", id,
2568                     reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2569                 if (msg != NULL)
2570                         xfree(msg);
2571                 if (lang != NULL)
2572                         xfree(lang);
2573                 if (c->open_confirm) {
2574                         debug2("callback start");
2575                         c->open_confirm(c->self, 0, c->open_confirm_ctx);
2576                         debug2("callback done");
2577                 }
2578         }
2579         packet_check_eom();
2580         /* Schedule the channel for cleanup/deletion. */
2581         chan_mark_dead(c);
2582 }
2583
2584 /* ARGSUSED */
2585 void
2586 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2587 {
2588         Channel *c;
2589         int id;
2590         u_int adjust;
2591
2592         if (!compat20)
2593                 return;
2594
2595         /* Get the channel number and verify it. */
2596         id = packet_get_int();
2597         c = channel_lookup(id);
2598
2599         if (c == NULL) {
2600                 logit("Received window adjust for non-open channel %d.", id);
2601                 return;
2602         }
2603         adjust = packet_get_int();
2604         packet_check_eom();
2605         debug2("channel %d: rcvd adjust %u", id, adjust);
2606         c->remote_window += adjust;
2607 }
2608
2609 /* ARGSUSED */
2610 void
2611 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2612 {
2613         Channel *c = NULL;
2614         u_short host_port;
2615         char *host, *originator_string;
2616         int remote_id;
2617
2618         remote_id = packet_get_int();
2619         host = packet_get_string(NULL);
2620         host_port = packet_get_int();
2621
2622         if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2623                 originator_string = packet_get_string(NULL);
2624         } else {
2625                 originator_string = xstrdup("unknown (remote did not supply name)");
2626         }
2627         packet_check_eom();
2628         c = channel_connect_to(host, host_port,
2629             "connected socket", originator_string);
2630         xfree(originator_string);
2631         xfree(host);
2632         if (c == NULL) {
2633                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2634                 packet_put_int(remote_id);
2635                 packet_send();
2636         } else
2637                 c->remote_id = remote_id;
2638 }
2639
2640 /* ARGSUSED */
2641 void
2642 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2643 {
2644         Channel *c;
2645         struct channel_confirm *cc;
2646         int id;
2647
2648         /* Reset keepalive timeout */
2649         packet_set_alive_timeouts(0);
2650
2651         id = packet_get_int();
2652         packet_check_eom();
2653
2654         debug2("channel_input_status_confirm: type %d id %d", type, id);
2655
2656         if ((c = channel_lookup(id)) == NULL) {
2657                 logit("channel_input_status_confirm: %d: unknown", id);
2658                 return;
2659         }
2660         ;
2661         if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2662                 return;
2663         cc->cb(type, c, cc->ctx);
2664         TAILQ_REMOVE(&c->status_confirms, cc, entry);
2665         bzero(cc, sizeof(*cc));
2666         xfree(cc);
2667 }
2668
2669 /* -- tcp forwarding */
2670
2671 void
2672 channel_set_af(int af)
2673 {
2674         IPv4or6 = af;
2675 }
2676
2677
2678 void
2679 channel_set_hpn(int external_hpn_disabled, int external_hpn_buffer_size)
2680 {
2681         hpn_disabled = external_hpn_disabled;
2682         hpn_buffer_size = external_hpn_buffer_size;
2683         debug("HPN Disabled: %d, HPN Buffer Size: %d", hpn_disabled, hpn_buffer_size);
2684 }
2685
2686 static int
2687 channel_setup_fwd_listener(int type, const char *listen_addr,
2688     u_short listen_port, int *allocated_listen_port,
2689     const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2690 {
2691         Channel *c;
2692         int sock, r, success = 0, wildcard = 0, is_client;
2693         struct addrinfo hints, *ai, *aitop;
2694         const char *host, *addr;
2695         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2696         in_port_t *lport_p;
2697
2698         host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2699             listen_addr : host_to_connect;
2700         is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2701
2702         if (host == NULL) {
2703                 error("No forward host name.");
2704                 return 0;
2705         }
2706         if (strlen(host) >= NI_MAXHOST) {
2707                 error("Forward host name too long.");
2708                 return 0;
2709         }
2710
2711         /*
2712          * Determine whether or not a port forward listens to loopback,
2713          * specified address or wildcard. On the client, a specified bind
2714          * address will always override gateway_ports. On the server, a
2715          * gateway_ports of 1 (``yes'') will override the client's
2716          * specification and force a wildcard bind, whereas a value of 2
2717          * (``clientspecified'') will bind to whatever address the client
2718          * asked for.
2719          *
2720          * Special-case listen_addrs are:
2721          *
2722          * "0.0.0.0"               -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2723          * "" (empty string), "*"  -> wildcard v4/v6
2724          * "localhost"             -> loopback v4/v6
2725          */
2726         addr = NULL;
2727         if (listen_addr == NULL) {
2728                 /* No address specified: default to gateway_ports setting */
2729                 if (gateway_ports)
2730                         wildcard = 1;
2731         } else if (gateway_ports || is_client) {
2732                 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2733                     strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2734                     *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2735                     (!is_client && gateway_ports == 1))
2736                         wildcard = 1;
2737                 else if (strcmp(listen_addr, "localhost") != 0)
2738                         addr = listen_addr;
2739         }
2740
2741         debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
2742             type, wildcard, (addr == NULL) ? "NULL" : addr);
2743
2744         /*
2745          * getaddrinfo returns a loopback address if the hostname is
2746          * set to NULL and hints.ai_flags is not AI_PASSIVE
2747          */
2748         memset(&hints, 0, sizeof(hints));
2749         hints.ai_family = IPv4or6;
2750         hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2751         hints.ai_socktype = SOCK_STREAM;
2752         snprintf(strport, sizeof strport, "%d", listen_port);
2753         if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2754                 if (addr == NULL) {
2755                         /* This really shouldn't happen */
2756                         packet_disconnect("getaddrinfo: fatal error: %s",
2757                             ssh_gai_strerror(r));
2758                 } else {
2759                         error("channel_setup_fwd_listener: "
2760                             "getaddrinfo(%.64s): %s", addr,
2761                             ssh_gai_strerror(r));
2762                 }
2763                 return 0;
2764         }
2765         if (allocated_listen_port != NULL)
2766                 *allocated_listen_port = 0;
2767         for (ai = aitop; ai; ai = ai->ai_next) {
2768                 switch (ai->ai_family) {
2769                 case AF_INET:
2770                         lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2771                             sin_port;
2772                         break;
2773                 case AF_INET6:
2774                         lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2775                             sin6_port;
2776                         break;
2777                 default:
2778                         continue;
2779                 }
2780                 /*
2781                  * If allocating a port for -R forwards, then use the
2782                  * same port for all address families.
2783                  */
2784                 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2785                     allocated_listen_port != NULL && *allocated_listen_port > 0)
2786                         *lport_p = htons(*allocated_listen_port);
2787
2788                 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2789                     strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2790                         error("channel_setup_fwd_listener: getnameinfo failed");
2791                         continue;
2792                 }
2793                 /* Create a port to listen for the host. */
2794                 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2795                 if (sock < 0) {
2796                         /* this is no error since kernel may not support ipv6 */
2797                         verbose("socket: %.100s", strerror(errno));
2798                         continue;
2799                 }
2800
2801                 channel_set_reuseaddr(sock);
2802                 if (ai->ai_family == AF_INET6)
2803                         sock_set_v6only(sock);
2804
2805                 debug("Local forwarding listening on %s port %s.",
2806                     ntop, strport);
2807
2808                 /* Bind the socket to the address. */
2809                 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2810                         /* address can be in use ipv6 address is already bound */
2811                         if (!ai->ai_next)
2812                                 error("bind: %.100s", strerror(errno));
2813                         else
2814                                 verbose("bind: %.100s", strerror(errno));
2815
2816                         close(sock);
2817                         continue;
2818                 }
2819                 /* Start listening for connections on the socket. */
2820                 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2821                         error("listen: %.100s", strerror(errno));
2822                         close(sock);
2823                         continue;
2824                 }
2825
2826                 /*
2827                  * listen_port == 0 requests a dynamically allocated port -
2828                  * record what we got.
2829                  */
2830                 if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
2831                     allocated_listen_port != NULL &&
2832                     *allocated_listen_port == 0) {
2833                         *allocated_listen_port = get_sock_port(sock, 1);
2834                         debug("Allocated listen port %d",
2835                             *allocated_listen_port);
2836                 }
2837
2838                 /* Allocate a channel number for the socket. */
2839                 /* explicitly test for hpn disabled option. if true use smaller window size */
2840                 if (hpn_disabled)
2841                 c = channel_new("port listener", type, sock, sock, -1,
2842                     CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2843                     0, "port listener", 1);
2844                 else
2845                         c = channel_new("port listener", type, sock, sock, -1,
2846                           hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT,
2847                           0, "port listener", 1);
2848                 c->path = xstrdup(host);
2849                 c->host_port = port_to_connect;
2850                 c->listening_port = listen_port;
2851                 success = 1;
2852         }
2853         if (success == 0)
2854                 error("channel_setup_fwd_listener: cannot listen to port: %d",
2855                     listen_port);
2856         freeaddrinfo(aitop);
2857         return success;
2858 }
2859
2860 int
2861 channel_cancel_rport_listener(const char *host, u_short port)
2862 {
2863         u_int i;
2864         int found = 0;
2865
2866         for (i = 0; i < channels_alloc; i++) {
2867                 Channel *c = channels[i];
2868
2869                 if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
2870                     strcmp(c->path, host) == 0 && c->listening_port == port) {
2871                         debug2("%s: close channel %d", __func__, i);
2872                         channel_free(c);
2873                         found = 1;
2874                 }
2875         }
2876
2877         return (found);
2878 }
2879
2880 /* protocol local port fwd, used by ssh (and sshd in v1) */
2881 int
2882 channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port,
2883     const char *host_to_connect, u_short port_to_connect, int gateway_ports)
2884 {
2885         return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
2886             listen_host, listen_port, NULL, host_to_connect, port_to_connect,
2887             gateway_ports);
2888 }
2889
2890 /* protocol v2 remote port fwd, used by sshd */
2891 int
2892 channel_setup_remote_fwd_listener(const char *listen_address,
2893     u_short listen_port, int *allocated_listen_port, int gateway_ports)
2894 {
2895         return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
2896             listen_address, listen_port, allocated_listen_port,
2897             NULL, 0, gateway_ports);
2898 }
2899
2900 /*
2901  * Initiate forwarding of connections to port "port" on remote host through
2902  * the secure channel to host:port from local side.
2903  */
2904
2905 int
2906 channel_request_remote_forwarding(const char *listen_host, u_short listen_port,
2907     const char *host_to_connect, u_short port_to_connect)
2908 {
2909         int type, success = 0;
2910
2911         /* Send the forward request to the remote side. */
2912         if (compat20) {
2913                 const char *address_to_bind;
2914                 if (listen_host == NULL) {
2915                         if (datafellows & SSH_BUG_RFWD_ADDR)
2916                                 address_to_bind = "127.0.0.1";
2917                         else
2918                                 address_to_bind = "localhost";
2919                 } else if (*listen_host == '\0' ||
2920                            strcmp(listen_host, "*") == 0) {
2921                         if (datafellows & SSH_BUG_RFWD_ADDR)
2922                                 address_to_bind = "0.0.0.0";
2923                         else
2924                                 address_to_bind = "";
2925                 } else
2926                         address_to_bind = listen_host;
2927
2928                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
2929                 packet_put_cstring("tcpip-forward");
2930                 packet_put_char(1);                     /* boolean: want reply */
2931                 packet_put_cstring(address_to_bind);
2932                 packet_put_int(listen_port);
2933                 packet_send();
2934                 packet_write_wait();
2935                 /* Assume that server accepts the request */
2936                 success = 1;
2937         } else {
2938                 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
2939                 packet_put_int(listen_port);
2940                 packet_put_cstring(host_to_connect);
2941                 packet_put_int(port_to_connect);
2942                 packet_send();
2943                 packet_write_wait();
2944
2945                 /* Wait for response from the remote side. */
2946                 type = packet_read();
2947                 switch (type) {
2948                 case SSH_SMSG_SUCCESS:
2949                         success = 1;
2950                         break;
2951                 case SSH_SMSG_FAILURE:
2952                         break;
2953                 default:
2954                         /* Unknown packet */
2955                         packet_disconnect("Protocol error for port forward request:"
2956                             "received packet type %d.", type);
2957                 }
2958         }
2959         if (success) {
2960                 /* Record that connection to this host/port is permitted. */
2961                 permitted_opens = xrealloc(permitted_opens,
2962                     num_permitted_opens + 1, sizeof(*permitted_opens));
2963                 permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
2964                 permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
2965                 permitted_opens[num_permitted_opens].listen_port = listen_port;
2966                 num_permitted_opens++;
2967         }
2968         return (success ? 0 : -1);
2969 }
2970
2971 /*
2972  * Request cancellation of remote forwarding of connection host:port from
2973  * local side.
2974  */
2975 void
2976 channel_request_rforward_cancel(const char *host, u_short port)
2977 {
2978         int i;
2979
2980         if (!compat20)
2981                 return;
2982
2983         for (i = 0; i < num_permitted_opens; i++) {
2984                 if (permitted_opens[i].host_to_connect != NULL &&
2985                     permitted_opens[i].listen_port == port)
2986                         break;
2987         }
2988         if (i >= num_permitted_opens) {
2989                 debug("%s: requested forward not found", __func__);
2990                 return;
2991         }
2992         packet_start(SSH2_MSG_GLOBAL_REQUEST);
2993         packet_put_cstring("cancel-tcpip-forward");
2994         packet_put_char(0);
2995         packet_put_cstring(host == NULL ? "" : host);
2996         packet_put_int(port);
2997         packet_send();
2998
2999         permitted_opens[i].listen_port = 0;
3000         permitted_opens[i].port_to_connect = 0;
3001         xfree(permitted_opens[i].host_to_connect);
3002         permitted_opens[i].host_to_connect = NULL;
3003 }
3004
3005 /*
3006  * This is called after receiving CHANNEL_FORWARDING_REQUEST.  This initates
3007  * listening for the port, and sends back a success reply (or disconnect
3008  * message if there was an error).
3009  */
3010 int
3011 channel_input_port_forward_request(int is_root, int gateway_ports)
3012 {
3013         u_short port, host_port;
3014         int success = 0;
3015         char *hostname;
3016
3017         /* Get arguments from the packet. */
3018         port = packet_get_int();
3019         hostname = packet_get_string(NULL);
3020         host_port = packet_get_int();
3021
3022 #ifndef HAVE_CYGWIN
3023         /*
3024          * Check that an unprivileged user is not trying to forward a
3025          * privileged port.
3026          */
3027         if (port < IPPORT_RESERVED && !is_root)
3028                 packet_disconnect(
3029                     "Requested forwarding of port %d but user is not root.",
3030                     port);
3031         if (host_port == 0)
3032                 packet_disconnect("Dynamic forwarding denied.");
3033 #endif
3034
3035         /* Initiate forwarding */
3036         success = channel_setup_local_fwd_listener(NULL, port, hostname,
3037             host_port, gateway_ports);
3038
3039         /* Free the argument string. */
3040         xfree(hostname);
3041
3042         return (success ? 0 : -1);
3043 }
3044
3045 /*
3046  * Permits opening to any host/port if permitted_opens[] is empty.  This is
3047  * usually called by the server, because the user could connect to any port
3048  * anyway, and the server has no way to know but to trust the client anyway.
3049  */
3050 void
3051 channel_permit_all_opens(void)
3052 {
3053         if (num_permitted_opens == 0)
3054                 all_opens_permitted = 1;
3055 }
3056
3057 void
3058 channel_add_permitted_opens(char *host, int port)
3059 {
3060         debug("allow port forwarding to host %s port %d", host, port);
3061
3062         permitted_opens = xrealloc(permitted_opens,
3063             num_permitted_opens + 1, sizeof(*permitted_opens));
3064         permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
3065         permitted_opens[num_permitted_opens].port_to_connect = port;
3066         num_permitted_opens++;
3067
3068         all_opens_permitted = 0;
3069 }
3070
3071 int
3072 channel_add_adm_permitted_opens(char *host, int port)
3073 {
3074         debug("config allows port forwarding to host %s port %d", host, port);
3075
3076         permitted_adm_opens = xrealloc(permitted_adm_opens,
3077             num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens));
3078         permitted_adm_opens[num_adm_permitted_opens].host_to_connect
3079              = xstrdup(host);
3080         permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
3081         return ++num_adm_permitted_opens;
3082 }
3083
3084 void
3085 channel_clear_permitted_opens(void)
3086 {
3087         int i;
3088
3089         for (i = 0; i < num_permitted_opens; i++)
3090                 if (permitted_opens[i].host_to_connect != NULL)
3091                         xfree(permitted_opens[i].host_to_connect);
3092         if (num_permitted_opens > 0) {
3093                 xfree(permitted_opens);
3094                 permitted_opens = NULL;
3095         }
3096         num_permitted_opens = 0;
3097 }
3098
3099 void
3100 channel_clear_adm_permitted_opens(void)
3101 {
3102         int i;
3103
3104         for (i = 0; i < num_adm_permitted_opens; i++)
3105                 if (permitted_adm_opens[i].host_to_connect != NULL)
3106                         xfree(permitted_adm_opens[i].host_to_connect);
3107         if (num_adm_permitted_opens > 0) {
3108                 xfree(permitted_adm_opens);
3109                 permitted_adm_opens = NULL;
3110         }
3111         num_adm_permitted_opens = 0;
3112 }
3113
3114 void
3115 channel_print_adm_permitted_opens(void)
3116 {
3117         int i;
3118
3119         printf("permitopen");
3120         if (num_adm_permitted_opens == 0) {
3121                 printf(" any\n");
3122                 return;
3123         }
3124         for (i = 0; i < num_adm_permitted_opens; i++)
3125                 if (permitted_adm_opens[i].host_to_connect != NULL)
3126                         printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
3127                             permitted_adm_opens[i].port_to_connect);
3128         printf("\n");
3129 }
3130
3131 /* Try to start non-blocking connect to next host in cctx list */
3132 static int
3133 connect_next(struct channel_connect *cctx)
3134 {
3135         int sock, saved_errno;
3136         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
3137
3138         for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
3139                 if (cctx->ai->ai_family != AF_INET &&
3140                     cctx->ai->ai_family != AF_INET6)
3141                         continue;
3142                 if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
3143                     ntop, sizeof(ntop), strport, sizeof(strport),
3144                     NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3145                         error("connect_next: getnameinfo failed");
3146                         continue;
3147                 }
3148                 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
3149                     cctx->ai->ai_protocol)) == -1) {
3150                         if (cctx->ai->ai_next == NULL)
3151                                 error("socket: %.100s", strerror(errno));
3152                         else
3153                                 verbose("socket: %.100s", strerror(errno));
3154                         continue;
3155                 }
3156                 if (set_nonblock(sock) == -1)
3157                         fatal("%s: set_nonblock(%d)", __func__, sock);
3158                 if (connect(sock, cctx->ai->ai_addr,
3159                     cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
3160                         debug("connect_next: host %.100s ([%.100s]:%s): "
3161                             "%.100s", cctx->host, ntop, strport,
3162                             strerror(errno));
3163                         saved_errno = errno;
3164                         close(sock);
3165                         errno = saved_errno;
3166                         continue;       /* fail -- try next */
3167                 }
3168                 debug("connect_next: host %.100s ([%.100s]:%s) "
3169                     "in progress, fd=%d", cctx->host, ntop, strport, sock);
3170                 cctx->ai = cctx->ai->ai_next;
3171                 set_nodelay(sock);
3172                 return sock;
3173         }
3174         return -1;
3175 }
3176
3177 static void
3178 channel_connect_ctx_free(struct channel_connect *cctx)
3179 {
3180         xfree(cctx->host);
3181         if (cctx->aitop)
3182                 freeaddrinfo(cctx->aitop);
3183         bzero(cctx, sizeof(*cctx));
3184         cctx->host = NULL;
3185         cctx->ai = cctx->aitop = NULL;
3186 }
3187
3188 /* Return CONNECTING channel to remote host, port */
3189 static Channel *
3190 connect_to(const char *host, u_short port, char *ctype, char *rname)
3191 {
3192         struct addrinfo hints;
3193         int gaierr;
3194         int sock = -1;
3195         char strport[NI_MAXSERV];
3196         struct channel_connect cctx;
3197         Channel *c;
3198
3199         memset(&cctx, 0, sizeof(cctx));
3200         memset(&hints, 0, sizeof(hints));
3201         hints.ai_family = IPv4or6;
3202         hints.ai_socktype = SOCK_STREAM;
3203         snprintf(strport, sizeof strport, "%d", port);
3204         if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) {
3205                 error("connect_to %.100s: unknown host (%s)", host,
3206                     ssh_gai_strerror(gaierr));
3207                 return NULL;
3208         }
3209
3210         cctx.host = xstrdup(host);
3211         cctx.port = port;
3212         cctx.ai = cctx.aitop;
3213
3214         if ((sock = connect_next(&cctx)) == -1) {
3215                 error("connect to %.100s port %d failed: %s",
3216                     host, port, strerror(errno));
3217                 channel_connect_ctx_free(&cctx);
3218                 return NULL;
3219         }
3220         c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3221             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3222         c->connect_ctx = cctx;
3223         return c;
3224 }
3225
3226 Channel *
3227 channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
3228 {
3229         int i;
3230
3231         for (i = 0; i < num_permitted_opens; i++) {
3232                 if (permitted_opens[i].host_to_connect != NULL &&
3233                     permitted_opens[i].listen_port == listen_port) {
3234                         return connect_to(
3235                             permitted_opens[i].host_to_connect,
3236                             permitted_opens[i].port_to_connect, ctype, rname);
3237                 }
3238         }
3239         error("WARNING: Server requests forwarding for unknown listen_port %d",
3240             listen_port);
3241         return NULL;
3242 }
3243
3244 /* Check if connecting to that port is permitted and connect. */
3245 Channel *
3246 channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
3247 {
3248         int i, permit, permit_adm = 1;
3249
3250         permit = all_opens_permitted;
3251         if (!permit) {
3252                 for (i = 0; i < num_permitted_opens; i++)
3253                         if (permitted_opens[i].host_to_connect != NULL &&
3254                             permitted_opens[i].port_to_connect == port &&
3255                             strcmp(permitted_opens[i].host_to_connect, host) == 0)
3256                                 permit = 1;
3257         }
3258
3259         if (num_adm_permitted_opens > 0) {
3260                 permit_adm = 0;
3261                 for (i = 0; i < num_adm_permitted_opens; i++)
3262                         if (permitted_adm_opens[i].host_to_connect != NULL &&
3263                             permitted_adm_opens[i].port_to_connect == port &&
3264                             strcmp(permitted_adm_opens[i].host_to_connect, host)
3265                             == 0)
3266                                 permit_adm = 1;
3267         }
3268
3269         if (!permit || !permit_adm) {
3270                 logit("Received request to connect to host %.100s port %d, "
3271                     "but the request was denied.", host, port);
3272                 return NULL;
3273         }
3274         return connect_to(host, port, ctype, rname);
3275 }
3276
3277 void
3278 channel_send_window_changes(void)
3279 {
3280         u_int i;
3281         struct winsize ws;
3282
3283         for (i = 0; i < channels_alloc; i++) {
3284                 if (channels[i] == NULL || !channels[i]->client_tty ||
3285                     channels[i]->type != SSH_CHANNEL_OPEN)
3286                         continue;
3287                 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3288                         continue;
3289                 channel_request_start(i, "window-change", 0);
3290                 packet_put_int((u_int)ws.ws_col);
3291                 packet_put_int((u_int)ws.ws_row);
3292                 packet_put_int((u_int)ws.ws_xpixel);
3293                 packet_put_int((u_int)ws.ws_ypixel);
3294                 packet_send();
3295         }
3296 }
3297
3298 /* -- X11 forwarding */
3299
3300 /*
3301  * Creates an internet domain socket for listening for X11 connections.
3302  * Returns 0 and a suitable display number for the DISPLAY variable
3303  * stored in display_numberp , or -1 if an error occurs.
3304  */
3305 int
3306 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3307     int single_connection, u_int *display_numberp, int **chanids)
3308 {
3309         Channel *nc = NULL;
3310         int display_number, sock;
3311         u_short port;
3312         struct addrinfo hints, *ai, *aitop;
3313         char strport[NI_MAXSERV];
3314         int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3315
3316         if (chanids == NULL)
3317                 return -1;
3318
3319         for (display_number = x11_display_offset;
3320             display_number < MAX_DISPLAYS;
3321             display_number++) {
3322                 port = 6000 + display_number;
3323                 memset(&hints, 0, sizeof(hints));
3324                 hints.ai_family = IPv4or6;
3325                 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3326                 hints.ai_socktype = SOCK_STREAM;
3327                 snprintf(strport, sizeof strport, "%d", port);
3328                 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3329                         error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3330                         return -1;
3331                 }
3332                 for (ai = aitop; ai; ai = ai->ai_next) {
3333                         if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3334                                 continue;
3335                         sock = socket(ai->ai_family, ai->ai_socktype,
3336                             ai->ai_protocol);
3337                         if (sock < 0) {
3338                                 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
3339 #ifdef EPFNOSUPPORT
3340                                     && (errno != EPFNOSUPPORT)
3341 #endif
3342                                     ) {
3343                                         error("socket: %.100s", strerror(errno));
3344                                         freeaddrinfo(aitop);
3345                                         return -1;
3346                                 } else {
3347                                         debug("x11_create_display_inet: Socket family %d not supported",
3348                                                  ai->ai_family);
3349                                         continue;
3350                                 }
3351                         }
3352                         if (ai->ai_family == AF_INET6)
3353                                 sock_set_v6only(sock);
3354                         if (x11_use_localhost)
3355                                 channel_set_reuseaddr(sock);
3356                         if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3357                                 debug2("bind port %d: %.100s", port, strerror(errno));
3358                                 close(sock);
3359
3360                                 for (n = 0; n < num_socks; n++) {
3361                                         close(socks[n]);
3362                                 }
3363                                 num_socks = 0;
3364                                 break;
3365                         }
3366                         socks[num_socks++] = sock;
3367                         if (num_socks == NUM_SOCKS)
3368                                 break;
3369                 }
3370                 freeaddrinfo(aitop);
3371                 if (num_socks > 0)
3372                         break;
3373         }
3374         if (display_number >= MAX_DISPLAYS) {
3375                 error("Failed to allocate internet-domain X11 display socket.");
3376                 return -1;
3377         }
3378         /* Start listening for connections on the socket. */
3379         for (n = 0; n < num_socks; n++) {
3380                 sock = socks[n];
3381                 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3382                         error("listen: %.100s", strerror(errno));
3383                         close(sock);
3384                         return -1;
3385                 }
3386         }
3387
3388         /* Allocate a channel for each socket. */
3389         *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3390         for (n = 0; n < num_socks; n++) {
3391                 sock = socks[n];
3392                 /* Is this really necassary? */
3393                 if (hpn_disabled)
3394                 nc = channel_new("x11 listener",
3395                     SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3396                     CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3397                     0, "X11 inet listener", 1);
3398                 else
3399                         nc = channel_new("x11 listener",
3400                             SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3401                             hpn_buffer_size, CHAN_X11_PACKET_DEFAULT,
3402                             0, "X11 inet listener", 1);
3403                 nc->single_connection = single_connection;
3404                 (*chanids)[n] = nc->self;
3405         }
3406         (*chanids)[n] = -1;
3407
3408         /* Return the display number for the DISPLAY environment variable. */
3409         *display_numberp = display_number;
3410         return (0);
3411 }
3412
3413 static int
3414 connect_local_xsocket_path(const char *pathname)
3415 {
3416         int sock;
3417         struct sockaddr_un addr;
3418
3419         sock = socket(AF_UNIX, SOCK_STREAM, 0);
3420         if (sock < 0)
3421                 error("socket: %.100s", strerror(errno));
3422         memset(&addr, 0, sizeof(addr));
3423         addr.sun_family = AF_UNIX;
3424         strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
3425         if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
3426                 return sock;
3427         close(sock);
3428         error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
3429         return -1;
3430 }
3431
3432 static int
3433 connect_local_xsocket(u_int dnr)
3434 {
3435         char buf[1024];
3436         snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
3437         return connect_local_xsocket_path(buf);
3438 }
3439
3440 int
3441 x11_connect_display(void)
3442 {
3443         u_int display_number;
3444         const char *display;
3445         char buf[1024], *cp;
3446         struct addrinfo hints, *ai, *aitop;
3447         char strport[NI_MAXSERV];
3448         int gaierr, sock = 0;
3449
3450         /* Try to open a socket for the local X server. */
3451         display = getenv("DISPLAY");
3452         if (!display) {
3453                 error("DISPLAY not set.");
3454                 return -1;
3455         }
3456         /*
3457          * Now we decode the value of the DISPLAY variable and make a
3458          * connection to the real X server.
3459          */
3460
3461         /* Check if the display is from launchd. */
3462 #ifdef __APPLE__
3463         if (strncmp(display, "/tmp/launch", 11) == 0) {
3464                 sock = connect_local_xsocket_path(display);
3465                 if (sock < 0)
3466                         return -1;
3467
3468                 /* OK, we now have a connection to the display. */
3469                 return sock;
3470         }
3471 #endif
3472         /*
3473          * Check if it is a unix domain socket.  Unix domain displays are in
3474          * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
3475          */
3476         if (strncmp(display, "unix:", 5) == 0 ||
3477             display[0] == ':') {
3478                 /* Connect to the unix domain socket. */
3479                 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
3480                         error("Could not parse display number from DISPLAY: %.100s",
3481                             display);
3482                         return -1;
3483                 }
3484                 /* Create a socket. */
3485                 sock = connect_local_xsocket(display_number);
3486                 if (sock < 0)
3487                         return -1;
3488
3489                 /* OK, we now have a connection to the display. */
3490                 return sock;
3491         }
3492         /*
3493          * Connect to an inet socket.  The DISPLAY value is supposedly
3494          * hostname:d[.s], where hostname may also be numeric IP address.
3495          */
3496         strlcpy(buf, display, sizeof(buf));
3497         cp = strchr(buf, ':');
3498         if (!cp) {
3499                 error("Could not find ':' in DISPLAY: %.100s", display);
3500                 return -1;
3501         }
3502         *cp = 0;
3503         /* buf now contains the host name.  But first we parse the display number. */
3504         if (sscanf(cp + 1, "%u", &display_number) != 1) {
3505                 error("Could not parse display number from DISPLAY: %.100s",
3506                     display);
3507                 return -1;
3508         }
3509
3510         /* Look up the host address */
3511         memset(&hints, 0, sizeof(hints));
3512         hints.ai_family = IPv4or6;
3513         hints.ai_socktype = SOCK_STREAM;
3514         snprintf(strport, sizeof strport, "%u", 6000 + display_number);
3515         if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
3516                 error("%.100s: unknown host. (%s)", buf,
3517                 ssh_gai_strerror(gaierr));
3518                 return -1;
3519         }
3520         for (ai = aitop; ai; ai = ai->ai_next) {
3521                 /* Create a socket. */
3522                 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
3523                 if (sock < 0) {
3524                         debug2("socket: %.100s", strerror(errno));
3525                         continue;
3526                 }
3527                 /* Connect it to the display. */
3528                 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3529                         debug2("connect %.100s port %u: %.100s", buf,
3530                             6000 + display_number, strerror(errno));
3531                         close(sock);
3532                         continue;
3533                 }
3534                 /* Success */
3535                 break;
3536         }
3537         freeaddrinfo(aitop);
3538         if (!ai) {
3539                 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
3540                     strerror(errno));
3541                 return -1;
3542         }
3543         set_nodelay(sock);
3544         return sock;
3545 }
3546
3547 /*
3548  * This is called when SSH_SMSG_X11_OPEN is received.  The packet contains
3549  * the remote channel number.  We should do whatever we want, and respond
3550  * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
3551  */
3552
3553 /* ARGSUSED */
3554 void
3555 x11_input_open(int type, u_int32_t seq, void *ctxt)
3556 {
3557         Channel *c = NULL;
3558         int remote_id, sock = 0;
3559         char *remote_host;
3560
3561         debug("Received X11 open request.");
3562
3563         remote_id = packet_get_int();
3564
3565         if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
3566                 remote_host = packet_get_string(NULL);
3567         } else {
3568                 remote_host = xstrdup("unknown (remote did not supply name)");
3569         }
3570         packet_check_eom();
3571
3572         /* Obtain a connection to the real X display. */
3573         sock = x11_connect_display();
3574         if (sock != -1) {
3575                 /* Allocate a channel for this connection. */
3576                 c = channel_new("connected x11 socket",
3577                     SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
3578                     remote_host, 1);
3579                 c->remote_id = remote_id;
3580                 c->force_drain = 1;
3581         }
3582         xfree(remote_host);
3583         if (c == NULL) {
3584                 /* Send refusal to the remote host. */
3585                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3586                 packet_put_int(remote_id);
3587         } else {
3588                 /* Send a confirmation to the remote host. */
3589                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
3590                 packet_put_int(remote_id);
3591                 packet_put_int(c->self);
3592         }
3593         packet_send();
3594 }
3595
3596 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
3597 /* ARGSUSED */
3598 void
3599 deny_input_open(int type, u_int32_t seq, void *ctxt)
3600 {
3601         int rchan = packet_get_int();
3602
3603         switch (type) {
3604         case SSH_SMSG_AGENT_OPEN:
3605                 error("Warning: ssh server tried agent forwarding.");
3606                 break;
3607         case SSH_SMSG_X11_OPEN:
3608                 error("Warning: ssh server tried X11 forwarding.");
3609                 break;
3610         default:
3611                 error("deny_input_open: type %d", type);
3612                 break;
3613         }
3614         error("Warning: this is probably a break-in attempt by a malicious server.");
3615         packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
3616         packet_put_int(rchan);
3617         packet_send();
3618 }
3619
3620 /*
3621  * Requests forwarding of X11 connections, generates fake authentication
3622  * data, and enables authentication spoofing.
3623  * This should be called in the client only.
3624  */
3625 void
3626 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
3627     const char *proto, const char *data, int want_reply)
3628 {
3629         u_int data_len = (u_int) strlen(data) / 2;
3630         u_int i, value;
3631         char *new_data;
3632         int screen_number;
3633         const char *cp;
3634         u_int32_t rnd = 0;
3635
3636         if (x11_saved_display == NULL)
3637                 x11_saved_display = xstrdup(disp);
3638         else if (strcmp(disp, x11_saved_display) != 0) {
3639                 error("x11_request_forwarding_with_spoofing: different "
3640                     "$DISPLAY already forwarded");
3641                 return;
3642         }
3643
3644         cp = strchr(disp, ':');
3645         if (cp)
3646                 cp = strchr(cp, '.');
3647         if (cp)
3648                 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
3649         else
3650                 screen_number = 0;
3651
3652         if (x11_saved_proto == NULL) {
3653                 /* Save protocol name. */
3654                 x11_saved_proto = xstrdup(proto);
3655                 /*
3656                  * Extract real authentication data and generate fake data
3657                  * of the same length.
3658                  */
3659                 x11_saved_data = xmalloc(data_len);
3660                 x11_fake_data = xmalloc(data_len);
3661                 for (i = 0; i < data_len; i++) {
3662                         if (sscanf(data + 2 * i, "%2x", &value) != 1)
3663                                 fatal("x11_request_forwarding: bad "
3664                                     "authentication data: %.100s", data);
3665                         if (i % 4 == 0)
3666                                 rnd = arc4random();
3667                         x11_saved_data[i] = value;
3668                         x11_fake_data[i] = rnd & 0xff;
3669                         rnd >>= 8;
3670                 }
3671                 x11_saved_data_len = data_len;
3672                 x11_fake_data_len = data_len;
3673         }
3674
3675         /* Convert the fake data into hex. */
3676         new_data = tohex(x11_fake_data, data_len);
3677
3678         /* Send the request packet. */
3679         if (compat20) {
3680                 channel_request_start(client_session_id, "x11-req", want_reply);
3681                 packet_put_char(0);     /* XXX bool single connection */
3682         } else {
3683                 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
3684         }
3685         packet_put_cstring(proto);
3686         packet_put_cstring(new_data);
3687         packet_put_int(screen_number);
3688         packet_send();
3689         packet_write_wait();
3690         xfree(new_data);
3691 }
3692
3693
3694 /* -- agent forwarding */
3695
3696 /* Sends a message to the server to request authentication fd forwarding. */
3697
3698 void
3699 auth_request_forwarding(void)
3700 {
3701         packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
3702         packet_send();
3703         packet_write_wait();
3704 }