crypto/openssh/channels.c

   1 /* $OpenBSD: channels.c,v 1.351 2016/07/19 11:38:53 dtucker 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/param.h>  /* MIN MAX */
  46 #include <sys/stat.h>
  47 #include <sys/ioctl.h>
  48 #include <sys/un.h>
  49 #include <sys/socket.h>
  50 #ifdef HAVE_SYS_TIME_H
  51 # include <sys/time.h>
  52 #endif
  53
  54 #include <netinet/in.h>
  55 #include <arpa/inet.h>
  56
  57 #include <errno.h>
  58 #include <fcntl.h>
  59 #include <netdb.h>
  60 #ifdef HAVE_STDINT_H
  61 #include <stdint.h>
  62 #endif
  63 #include <stdio.h>
  64 #include <stdlib.h>
  65 #include <string.h>
  66 #include <termios.h>
  67 #include <unistd.h>
  68 #include <stdarg.h>
  69
  70 #include "openbsd-compat/sys-queue.h"
  71 #include "xmalloc.h"
  72 #include "ssh.h"
  73 #include "ssh1.h"
  74 #include "ssh2.h"
  75 #include "packet.h"
  76 #include "log.h"
  77 #include "misc.h"
  78 #include "buffer.h"
  79 #include "channels.h"
  80 #include "compat.h"
  81 #include "canohost.h"
  82 #include "key.h"
  83 #include "authfd.h"
  84 #include "pathnames.h"
  85
  86 /* -- channel core */
  87
  88 /*
  89  * Pointer to an array containing all allocated channels.  The array is
  90  * dynamically extended as needed.
  91  */
  92 static Channel **channels = NULL;
  93
  94 /*
  95  * Size of the channel array.  All slots of the array must always be
  96  * initialized (at least the type field); unused slots set to NULL
  97  */
  98 static u_int channels_alloc = 0;
  99
 100 /*
 101  * Maximum file descriptor value used in any of the channels.  This is
 102  * updated in channel_new.
 103  */
 104 static int channel_max_fd = 0;
 105
 106
 107 /* -- tcp forwarding */
 108
 109 /*
 110  * Data structure for storing which hosts are permitted for forward requests.
 111  * The local sides of any remote forwards are stored in this array to prevent
 112  * a corrupt remote server from accessing arbitrary TCP/IP ports on our local
 113  * network (which might be behind a firewall).
 114  */
 115 /* XXX: streamlocal wants a path instead of host:port */
 116 /*      Overload host_to_connect; we could just make this match Forward */
 117 /*      XXX - can we use listen_host instead of listen_path? */
 118 typedef struct {
 119         char *host_to_connect;          /* Connect to 'host'. */
 120         int port_to_connect;            /* Connect to 'port'. */
 121         char *listen_host;              /* Remote side should listen address. */
 122         char *listen_path;              /* Remote side should listen path. */
 123         int listen_port;                /* Remote side should listen port. */
 124 } ForwardPermission;
 125
 126 /* List of all permitted host/port pairs to connect by the user. */
 127 static ForwardPermission *permitted_opens = NULL;
 128
 129 /* List of all permitted host/port pairs to connect by the admin. */
 130 static ForwardPermission *permitted_adm_opens = NULL;
 131
 132 /* Number of permitted host/port pairs in the array permitted by the user. */
 133 static int num_permitted_opens = 0;
 134
 135 /* Number of permitted host/port pair in the array permitted by the admin. */
 136 static int num_adm_permitted_opens = 0;
 137
 138 /* special-case port number meaning allow any port */
 139 #define FWD_PERMIT_ANY_PORT     0
 140
 141 /* special-case wildcard meaning allow any host */
 142 #define FWD_PERMIT_ANY_HOST     "*"
 143
 144 /*
 145  * If this is true, all opens are permitted.  This is the case on the server
 146  * on which we have to trust the client anyway, and the user could do
 147  * anything after logging in anyway.
 148  */
 149 static int all_opens_permitted = 0;
 150
 151
 152 /* -- X11 forwarding */
 153
 154 /* Maximum number of fake X11 displays to try. */
 155 #define MAX_DISPLAYS  1000
 156
 157 /* Saved X11 local (client) display. */
 158 static char *x11_saved_display = NULL;
 159
 160 /* Saved X11 authentication protocol name. */
 161 static char *x11_saved_proto = NULL;
 162
 163 /* Saved X11 authentication data.  This is the real data. */
 164 static char *x11_saved_data = NULL;
 165 static u_int x11_saved_data_len = 0;
 166
 167 /* Deadline after which all X11 connections are refused */
 168 static u_int x11_refuse_time;
 169
 170 /*
 171  * Fake X11 authentication data.  This is what the server will be sending us;
 172  * we should replace any occurrences of this by the real data.
 173  */
 174 static u_char *x11_fake_data = NULL;
 175 static u_int x11_fake_data_len;
 176
 177
 178 /* -- agent forwarding */
 179
 180 #define NUM_SOCKS       10
 181
 182 /* AF_UNSPEC or AF_INET or AF_INET6 */
 183 static int IPv4or6 = AF_UNSPEC;
 184
 185 /* helper */
 186 static void port_open_helper(Channel *c, char *rtype);
 187
 188 /* non-blocking connect helpers */
 189 static int connect_next(struct channel_connect *);
 190 static void channel_connect_ctx_free(struct channel_connect *);
 191
 192 /* -- channel core */
 193
 194 Channel *
 195 channel_by_id(int id)
 196 {
 197         Channel *c;
 198
 199         if (id < 0 || (u_int)id >= channels_alloc) {
 200                 logit("channel_by_id: %d: bad id", id);
 201                 return NULL;
 202         }
 203         c = channels[id];
 204         if (c == NULL) {
 205                 logit("channel_by_id: %d: bad id: channel free", id);
 206                 return NULL;
 207         }
 208         return c;
 209 }
 210
 211 /*
 212  * Returns the channel if it is allowed to receive protocol messages.
 213  * Private channels, like listening sockets, may not receive messages.
 214  */
 215 Channel *
 216 channel_lookup(int id)
 217 {
 218         Channel *c;
 219
 220         if ((c = channel_by_id(id)) == NULL)
 221                 return (NULL);
 222
 223         switch (c->type) {
 224         case SSH_CHANNEL_X11_OPEN:
 225         case SSH_CHANNEL_LARVAL:
 226         case SSH_CHANNEL_CONNECTING:
 227         case SSH_CHANNEL_DYNAMIC:
 228         case SSH_CHANNEL_OPENING:
 229         case SSH_CHANNEL_OPEN:
 230         case SSH_CHANNEL_INPUT_DRAINING:
 231         case SSH_CHANNEL_OUTPUT_DRAINING:
 232         case SSH_CHANNEL_ABANDONED:
 233                 return (c);
 234         }
 235         logit("Non-public channel %d, type %d.", id, c->type);
 236         return (NULL);
 237 }
 238
 239 /*
 240  * Register filedescriptors for a channel, used when allocating a channel or
 241  * when the channel consumer/producer is ready, e.g. shell exec'd
 242  */
 243 static void
 244 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
 245     int extusage, int nonblock, int is_tty)
 246 {
 247         /* Update the maximum file descriptor value. */
 248         channel_max_fd = MAX(channel_max_fd, rfd);
 249         channel_max_fd = MAX(channel_max_fd, wfd);
 250         channel_max_fd = MAX(channel_max_fd, efd);
 251
 252         if (rfd != -1)
 253                 fcntl(rfd, F_SETFD, FD_CLOEXEC);
 254         if (wfd != -1 && wfd != rfd)
 255                 fcntl(wfd, F_SETFD, FD_CLOEXEC);
 256         if (efd != -1 && efd != rfd && efd != wfd)
 257                 fcntl(efd, F_SETFD, FD_CLOEXEC);
 258
 259         c->rfd = rfd;
 260         c->wfd = wfd;
 261         c->sock = (rfd == wfd) ? rfd : -1;
 262         c->efd = efd;
 263         c->extended_usage = extusage;
 264
 265         if ((c->isatty = is_tty) != 0)
 266                 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
 267 #ifdef _AIX
 268         /* XXX: Later AIX versions can't push as much data to tty */
 269         c->wfd_isatty = is_tty || isatty(c->wfd);
 270 #endif
 271
 272         /* enable nonblocking mode */
 273         if (nonblock) {
 274                 if (rfd != -1)
 275                         set_nonblock(rfd);
 276                 if (wfd != -1)
 277                         set_nonblock(wfd);
 278                 if (efd != -1)
 279                         set_nonblock(efd);
 280         }
 281 }
 282
 283 /*
 284  * Allocate a new channel object and set its type and socket. This will cause
 285  * remote_name to be freed.
 286  */
 287 Channel *
 288 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
 289     u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
 290 {
 291         int found;
 292         u_int i;
 293         Channel *c;
 294
 295         /* Do initial allocation if this is the first call. */
 296         if (channels_alloc == 0) {
 297                 channels_alloc = 10;
 298                 channels = xcalloc(channels_alloc, sizeof(Channel *));
 299                 for (i = 0; i < channels_alloc; i++)
 300                         channels[i] = NULL;
 301         }
 302         /* Try to find a free slot where to put the new channel. */
 303         for (found = -1, i = 0; i < channels_alloc; i++)
 304                 if (channels[i] == NULL) {
 305                         /* Found a free slot. */
 306                         found = (int)i;
 307                         break;
 308                 }
 309         if (found < 0) {
 310                 /* There are no free slots.  Take last+1 slot and expand the array.  */
 311                 found = channels_alloc;
 312                 if (channels_alloc > 10000)
 313                         fatal("channel_new: internal error: channels_alloc %d "
 314                             "too big.", channels_alloc);
 315                 channels = xreallocarray(channels, channels_alloc + 10,
 316                     sizeof(Channel *));
 317                 channels_alloc += 10;
 318                 debug2("channel: expanding %d", channels_alloc);
 319                 for (i = found; i < channels_alloc; i++)
 320                         channels[i] = NULL;
 321         }
 322         /* Initialize and return new channel. */
 323         c = channels[found] = xcalloc(1, sizeof(Channel));
 324         buffer_init(&c->input);
 325         buffer_init(&c->output);
 326         buffer_init(&c->extended);
 327         c->path = NULL;
 328         c->listening_addr = NULL;
 329         c->listening_port = 0;
 330         c->ostate = CHAN_OUTPUT_OPEN;
 331         c->istate = CHAN_INPUT_OPEN;
 332         c->flags = 0;
 333         channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
 334         c->notbefore = 0;
 335         c->self = found;
 336         c->type = type;
 337         c->ctype = ctype;
 338         c->local_window = window;
 339         c->local_window_max = window;
 340         c->local_consumed = 0;
 341         c->local_maxpacket = maxpack;
 342         c->remote_id = -1;
 343         c->remote_name = xstrdup(remote_name);
 344         c->remote_window = 0;
 345         c->remote_maxpacket = 0;
 346         c->force_drain = 0;
 347         c->single_connection = 0;
 348         c->detach_user = NULL;
 349         c->detach_close = 0;
 350         c->open_confirm = NULL;
 351         c->open_confirm_ctx = NULL;
 352         c->input_filter = NULL;
 353         c->output_filter = NULL;
 354         c->filter_ctx = NULL;
 355         c->filter_cleanup = NULL;
 356         c->ctl_chan = -1;
 357         c->mux_rcb = NULL;
 358         c->mux_ctx = NULL;
 359         c->mux_pause = 0;
 360         c->delayed = 1;         /* prevent call to channel_post handler */
 361         TAILQ_INIT(&c->status_confirms);
 362         debug("channel %d: new [%s]", found, remote_name);
 363         return c;
 364 }
 365
 366 static int
 367 channel_find_maxfd(void)
 368 {
 369         u_int i;
 370         int max = 0;
 371         Channel *c;
 372
 373         for (i = 0; i < channels_alloc; i++) {
 374                 c = channels[i];
 375                 if (c != NULL) {
 376                         max = MAX(max, c->rfd);
 377                         max = MAX(max, c->wfd);
 378                         max = MAX(max, c->efd);
 379                 }
 380         }
 381         return max;
 382 }
 383
 384 int
 385 channel_close_fd(int *fdp)
 386 {
 387         int ret = 0, fd = *fdp;
 388
 389         if (fd != -1) {
 390                 ret = close(fd);
 391                 *fdp = -1;
 392                 if (fd == channel_max_fd)
 393                         channel_max_fd = channel_find_maxfd();
 394         }
 395         return ret;
 396 }
 397
 398 /* Close all channel fd/socket. */
 399 static void
 400 channel_close_fds(Channel *c)
 401 {
 402         channel_close_fd(&c->sock);
 403         channel_close_fd(&c->rfd);
 404         channel_close_fd(&c->wfd);
 405         channel_close_fd(&c->efd);
 406 }
 407
 408 /* Free the channel and close its fd/socket. */
 409 void
 410 channel_free(Channel *c)
 411 {
 412         char *s;
 413         u_int i, n;
 414         struct channel_confirm *cc;
 415
 416         for (n = 0, i = 0; i < channels_alloc; i++)
 417                 if (channels[i])
 418                         n++;
 419         debug("channel %d: free: %s, nchannels %u", c->self,
 420             c->remote_name ? c->remote_name : "???", n);
 421
 422         s = channel_open_message();
 423         debug3("channel %d: status: %s", c->self, s);
 424         free(s);
 425
 426         if (c->sock != -1)
 427                 shutdown(c->sock, SHUT_RDWR);
 428         channel_close_fds(c);
 429         buffer_free(&c->input);
 430         buffer_free(&c->output);
 431         buffer_free(&c->extended);
 432         free(c->remote_name);
 433         c->remote_name = NULL;
 434         free(c->path);
 435         c->path = NULL;
 436         free(c->listening_addr);
 437         c->listening_addr = NULL;
 438         while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
 439                 if (cc->abandon_cb != NULL)
 440                         cc->abandon_cb(c, cc->ctx);
 441                 TAILQ_REMOVE(&c->status_confirms, cc, entry);
 442                 explicit_bzero(cc, sizeof(*cc));
 443                 free(cc);
 444         }
 445         if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
 446                 c->filter_cleanup(c->self, c->filter_ctx);
 447         channels[c->self] = NULL;
 448         free(c);
 449 }
 450
 451 void
 452 channel_free_all(void)
 453 {
 454         u_int i;
 455
 456         for (i = 0; i < channels_alloc; i++)
 457                 if (channels[i] != NULL)
 458                         channel_free(channels[i]);
 459 }
 460
 461 /*
 462  * Closes the sockets/fds of all channels.  This is used to close extra file
 463  * descriptors after a fork.
 464  */
 465 void
 466 channel_close_all(void)
 467 {
 468         u_int i;
 469
 470         for (i = 0; i < channels_alloc; i++)
 471                 if (channels[i] != NULL)
 472                         channel_close_fds(channels[i]);
 473 }
 474
 475 /*
 476  * Stop listening to channels.
 477  */
 478 void
 479 channel_stop_listening(void)
 480 {
 481         u_int i;
 482         Channel *c;
 483
 484         for (i = 0; i < channels_alloc; i++) {
 485                 c = channels[i];
 486                 if (c != NULL) {
 487                         switch (c->type) {
 488                         case SSH_CHANNEL_AUTH_SOCKET:
 489                         case SSH_CHANNEL_PORT_LISTENER:
 490                         case SSH_CHANNEL_RPORT_LISTENER:
 491                         case SSH_CHANNEL_X11_LISTENER:
 492                         case SSH_CHANNEL_UNIX_LISTENER:
 493                         case SSH_CHANNEL_RUNIX_LISTENER:
 494                                 channel_close_fd(&c->sock);
 495                                 channel_free(c);
 496                                 break;
 497                         }
 498                 }
 499         }
 500 }
 501
 502 /*
 503  * Returns true if no channel has too much buffered data, and false if one or
 504  * more channel is overfull.
 505  */
 506 int
 507 channel_not_very_much_buffered_data(void)
 508 {
 509         u_int i;
 510         Channel *c;
 511
 512         for (i = 0; i < channels_alloc; i++) {
 513                 c = channels[i];
 514                 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
 515 #if 0
 516                         if (!compat20 &&
 517                             buffer_len(&c->input) > packet_get_maxsize()) {
 518                                 debug2("channel %d: big input buffer %d",
 519                                     c->self, buffer_len(&c->input));
 520                                 return 0;
 521                         }
 522 #endif
 523                         if (buffer_len(&c->output) > packet_get_maxsize()) {
 524                                 debug2("channel %d: big output buffer %u > %u",
 525                                     c->self, buffer_len(&c->output),
 526                                     packet_get_maxsize());
 527                                 return 0;
 528                         }
 529                 }
 530         }
 531         return 1;
 532 }
 533
 534 /* Returns true if any channel is still open. */
 535 int
 536 channel_still_open(void)
 537 {
 538         u_int i;
 539         Channel *c;
 540
 541         for (i = 0; i < channels_alloc; i++) {
 542                 c = channels[i];
 543                 if (c == NULL)
 544                         continue;
 545                 switch (c->type) {
 546                 case SSH_CHANNEL_X11_LISTENER:
 547                 case SSH_CHANNEL_PORT_LISTENER:
 548                 case SSH_CHANNEL_RPORT_LISTENER:
 549                 case SSH_CHANNEL_MUX_LISTENER:
 550                 case SSH_CHANNEL_CLOSED:
 551                 case SSH_CHANNEL_AUTH_SOCKET:
 552                 case SSH_CHANNEL_DYNAMIC:
 553                 case SSH_CHANNEL_CONNECTING:
 554                 case SSH_CHANNEL_ZOMBIE:
 555                 case SSH_CHANNEL_ABANDONED:
 556                 case SSH_CHANNEL_UNIX_LISTENER:
 557                 case SSH_CHANNEL_RUNIX_LISTENER:
 558                         continue;
 559                 case SSH_CHANNEL_LARVAL:
 560                         if (!compat20)
 561                                 fatal("cannot happen: SSH_CHANNEL_LARVAL");
 562                         continue;
 563                 case SSH_CHANNEL_OPENING:
 564                 case SSH_CHANNEL_OPEN:
 565                 case SSH_CHANNEL_X11_OPEN:
 566                 case SSH_CHANNEL_MUX_CLIENT:
 567                         return 1;
 568                 case SSH_CHANNEL_INPUT_DRAINING:
 569                 case SSH_CHANNEL_OUTPUT_DRAINING:
 570                         if (!compat13)
 571                                 fatal("cannot happen: OUT_DRAIN");
 572                         return 1;
 573                 default:
 574                         fatal("channel_still_open: bad channel type %d", c->type);
 575                         /* NOTREACHED */
 576                 }
 577         }
 578         return 0;
 579 }
 580
 581 /* Returns the id of an open channel suitable for keepaliving */
 582 int
 583 channel_find_open(void)
 584 {
 585         u_int i;
 586         Channel *c;
 587
 588         for (i = 0; i < channels_alloc; i++) {
 589                 c = channels[i];
 590                 if (c == NULL || c->remote_id < 0)
 591                         continue;
 592                 switch (c->type) {
 593                 case SSH_CHANNEL_CLOSED:
 594                 case SSH_CHANNEL_DYNAMIC:
 595                 case SSH_CHANNEL_X11_LISTENER:
 596                 case SSH_CHANNEL_PORT_LISTENER:
 597                 case SSH_CHANNEL_RPORT_LISTENER:
 598                 case SSH_CHANNEL_MUX_LISTENER:
 599                 case SSH_CHANNEL_MUX_CLIENT:
 600                 case SSH_CHANNEL_OPENING:
 601                 case SSH_CHANNEL_CONNECTING:
 602                 case SSH_CHANNEL_ZOMBIE:
 603                 case SSH_CHANNEL_ABANDONED:
 604                 case SSH_CHANNEL_UNIX_LISTENER:
 605                 case SSH_CHANNEL_RUNIX_LISTENER:
 606                         continue;
 607                 case SSH_CHANNEL_LARVAL:
 608                 case SSH_CHANNEL_AUTH_SOCKET:
 609                 case SSH_CHANNEL_OPEN:
 610                 case SSH_CHANNEL_X11_OPEN:
 611                         return i;
 612                 case SSH_CHANNEL_INPUT_DRAINING:
 613                 case SSH_CHANNEL_OUTPUT_DRAINING:
 614                         if (!compat13)
 615                                 fatal("cannot happen: OUT_DRAIN");
 616                         return i;
 617                 default:
 618                         fatal("channel_find_open: bad channel type %d", c->type);
 619                         /* NOTREACHED */
 620                 }
 621         }
 622         return -1;
 623 }
 624
 625
 626 /*
 627  * Returns a message describing the currently open forwarded connections,
 628  * suitable for sending to the client.  The message contains crlf pairs for
 629  * newlines.
 630  */
 631 char *
 632 channel_open_message(void)
 633 {
 634         Buffer buffer;
 635         Channel *c;
 636         char buf[1024], *cp;
 637         u_int i;
 638
 639         buffer_init(&buffer);
 640         snprintf(buf, sizeof buf, "The following connections are open:\r\n");
 641         buffer_append(&buffer, buf, strlen(buf));
 642         for (i = 0; i < channels_alloc; i++) {
 643                 c = channels[i];
 644                 if (c == NULL)
 645                         continue;
 646                 switch (c->type) {
 647                 case SSH_CHANNEL_X11_LISTENER:
 648                 case SSH_CHANNEL_PORT_LISTENER:
 649                 case SSH_CHANNEL_RPORT_LISTENER:
 650                 case SSH_CHANNEL_CLOSED:
 651                 case SSH_CHANNEL_AUTH_SOCKET:
 652                 case SSH_CHANNEL_ZOMBIE:
 653                 case SSH_CHANNEL_ABANDONED:
 654                 case SSH_CHANNEL_MUX_CLIENT:
 655                 case SSH_CHANNEL_MUX_LISTENER:
 656                 case SSH_CHANNEL_UNIX_LISTENER:
 657                 case SSH_CHANNEL_RUNIX_LISTENER:
 658                         continue;
 659                 case SSH_CHANNEL_LARVAL:
 660                 case SSH_CHANNEL_OPENING:
 661                 case SSH_CHANNEL_CONNECTING:
 662                 case SSH_CHANNEL_DYNAMIC:
 663                 case SSH_CHANNEL_OPEN:
 664                 case SSH_CHANNEL_X11_OPEN:
 665                 case SSH_CHANNEL_INPUT_DRAINING:
 666                 case SSH_CHANNEL_OUTPUT_DRAINING:
 667                         snprintf(buf, sizeof buf,
 668                             "  #%d %.300s (t%d r%d i%u/%d o%u/%d fd %d/%d cc %d)\r\n",
 669                             c->self, c->remote_name,
 670                             c->type, c->remote_id,
 671                             c->istate, buffer_len(&c->input),
 672                             c->ostate, buffer_len(&c->output),
 673                             c->rfd, c->wfd, c->ctl_chan);
 674                         buffer_append(&buffer, buf, strlen(buf));
 675                         continue;
 676                 default:
 677                         fatal("channel_open_message: bad channel type %d", c->type);
 678                         /* NOTREACHED */
 679                 }
 680         }
 681         buffer_append(&buffer, "\0", 1);
 682         cp = xstrdup((char *)buffer_ptr(&buffer));
 683         buffer_free(&buffer);
 684         return cp;
 685 }
 686
 687 void
 688 channel_send_open(int id)
 689 {
 690         Channel *c = channel_lookup(id);
 691
 692         if (c == NULL) {
 693                 logit("channel_send_open: %d: bad id", id);
 694                 return;
 695         }
 696         debug2("channel %d: send open", id);
 697         packet_start(SSH2_MSG_CHANNEL_OPEN);
 698         packet_put_cstring(c->ctype);
 699         packet_put_int(c->self);
 700         packet_put_int(c->local_window);
 701         packet_put_int(c->local_maxpacket);
 702         packet_send();
 703 }
 704
 705 void
 706 channel_request_start(int id, char *service, int wantconfirm)
 707 {
 708         Channel *c = channel_lookup(id);
 709
 710         if (c == NULL) {
 711                 logit("channel_request_start: %d: unknown channel id", id);
 712                 return;
 713         }
 714         debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
 715         packet_start(SSH2_MSG_CHANNEL_REQUEST);
 716         packet_put_int(c->remote_id);
 717         packet_put_cstring(service);
 718         packet_put_char(wantconfirm);
 719 }
 720
 721 void
 722 channel_register_status_confirm(int id, channel_confirm_cb *cb,
 723     channel_confirm_abandon_cb *abandon_cb, void *ctx)
 724 {
 725         struct channel_confirm *cc;
 726         Channel *c;
 727
 728         if ((c = channel_lookup(id)) == NULL)
 729                 fatal("channel_register_expect: %d: bad id", id);
 730
 731         cc = xcalloc(1, sizeof(*cc));
 732         cc->cb = cb;
 733         cc->abandon_cb = abandon_cb;
 734         cc->ctx = ctx;
 735         TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
 736 }
 737
 738 void
 739 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
 740 {
 741         Channel *c = channel_lookup(id);
 742
 743         if (c == NULL) {
 744                 logit("channel_register_open_confirm: %d: bad id", id);
 745                 return;
 746         }
 747         c->open_confirm = fn;
 748         c->open_confirm_ctx = ctx;
 749 }
 750
 751 void
 752 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
 753 {
 754         Channel *c = channel_by_id(id);
 755
 756         if (c == NULL) {
 757                 logit("channel_register_cleanup: %d: bad id", id);
 758                 return;
 759         }
 760         c->detach_user = fn;
 761         c->detach_close = do_close;
 762 }
 763
 764 void
 765 channel_cancel_cleanup(int id)
 766 {
 767         Channel *c = channel_by_id(id);
 768
 769         if (c == NULL) {
 770                 logit("channel_cancel_cleanup: %d: bad id", id);
 771                 return;
 772         }
 773         c->detach_user = NULL;
 774         c->detach_close = 0;
 775 }
 776
 777 void
 778 channel_register_filter(int id, channel_infilter_fn *ifn,
 779     channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
 780 {
 781         Channel *c = channel_lookup(id);
 782
 783         if (c == NULL) {
 784                 logit("channel_register_filter: %d: bad id", id);
 785                 return;
 786         }
 787         c->input_filter = ifn;
 788         c->output_filter = ofn;
 789         c->filter_ctx = ctx;
 790         c->filter_cleanup = cfn;
 791 }
 792
 793 void
 794 channel_set_fds(int id, int rfd, int wfd, int efd,
 795     int extusage, int nonblock, int is_tty, u_int window_max)
 796 {
 797         Channel *c = channel_lookup(id);
 798
 799         if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
 800                 fatal("channel_activate for non-larval channel %d.", id);
 801         channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
 802         c->type = SSH_CHANNEL_OPEN;
 803         c->local_window = c->local_window_max = window_max;
 804         packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
 805         packet_put_int(c->remote_id);
 806         packet_put_int(c->local_window);
 807         packet_send();
 808 }
 809
 810 /*
 811  * 'channel_pre*' are called just before select() to add any bits relevant to
 812  * channels in the select bitmasks.
 813  */
 814 /*
 815  * 'channel_post*': perform any appropriate operations for channels which
 816  * have events pending.
 817  */
 818 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
 819 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
 820 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
 821
 822 /* ARGSUSED */
 823 static void
 824 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
 825 {
 826         FD_SET(c->sock, readset);
 827 }
 828
 829 /* ARGSUSED */
 830 static void
 831 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
 832 {
 833         debug3("channel %d: waiting for connection", c->self);
 834         FD_SET(c->sock, writeset);
 835 }
 836
 837 static void
 838 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
 839 {
 840         if (buffer_len(&c->input) < packet_get_maxsize())
 841                 FD_SET(c->sock, readset);
 842         if (buffer_len(&c->output) > 0)
 843                 FD_SET(c->sock, writeset);
 844 }
 845
 846 static void
 847 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
 848 {
 849         u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
 850
 851         if (c->istate == CHAN_INPUT_OPEN &&
 852             limit > 0 &&
 853             buffer_len(&c->input) < limit &&
 854             buffer_check_alloc(&c->input, CHAN_RBUF))
 855                 FD_SET(c->rfd, readset);
 856         if (c->ostate == CHAN_OUTPUT_OPEN ||
 857             c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
 858                 if (buffer_len(&c->output) > 0) {
 859                         FD_SET(c->wfd, writeset);
 860                 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
 861                         if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
 862                                 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
 863                                     c->self, c->efd, buffer_len(&c->extended));
 864                         else
 865                                 chan_obuf_empty(c);
 866                 }
 867         }
 868         /** XXX check close conditions, too */
 869         if (compat20 && c->efd != -1 &&
 870             !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
 871                 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
 872                     buffer_len(&c->extended) > 0)
 873                         FD_SET(c->efd, writeset);
 874                 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
 875                     (c->extended_usage == CHAN_EXTENDED_READ ||
 876                     c->extended_usage == CHAN_EXTENDED_IGNORE) &&
 877                     buffer_len(&c->extended) < c->remote_window)
 878                         FD_SET(c->efd, readset);
 879         }
 880         /* XXX: What about efd? races? */
 881 }
 882
 883 /* ARGSUSED */
 884 static void
 885 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
 886 {
 887         if (buffer_len(&c->input) == 0) {
 888                 packet_start(SSH_MSG_CHANNEL_CLOSE);
 889                 packet_put_int(c->remote_id);
 890                 packet_send();
 891                 c->type = SSH_CHANNEL_CLOSED;
 892                 debug2("channel %d: closing after input drain.", c->self);
 893         }
 894 }
 895
 896 /* ARGSUSED */
 897 static void
 898 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
 899 {
 900         if (buffer_len(&c->output) == 0)
 901                 chan_mark_dead(c);
 902         else
 903                 FD_SET(c->sock, writeset);
 904 }
 905
 906 /*
 907  * This is a special state for X11 authentication spoofing.  An opened X11
 908  * connection (when authentication spoofing is being done) remains in this
 909  * state until the first packet has been completely read.  The authentication
 910  * data in that packet is then substituted by the real data if it matches the
 911  * fake data, and the channel is put into normal mode.
 912  * XXX All this happens at the client side.
 913  * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
 914  */
 915 static int
 916 x11_open_helper(Buffer *b)
 917 {
 918         u_char *ucp;
 919         u_int proto_len, data_len;
 920
 921         /* Is this being called after the refusal deadline? */
 922         if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) {
 923                 verbose("Rejected X11 connection after ForwardX11Timeout "
 924                     "expired");
 925                 return -1;
 926         }
 927
 928         /* Check if the fixed size part of the packet is in buffer. */
 929         if (buffer_len(b) < 12)
 930                 return 0;
 931
 932         /* Parse the lengths of variable-length fields. */
 933         ucp = buffer_ptr(b);
 934         if (ucp[0] == 0x42) {   /* Byte order MSB first. */
 935                 proto_len = 256 * ucp[6] + ucp[7];
 936                 data_len = 256 * ucp[8] + ucp[9];
 937         } else if (ucp[0] == 0x6c) {    /* Byte order LSB first. */
 938                 proto_len = ucp[6] + 256 * ucp[7];
 939                 data_len = ucp[8] + 256 * ucp[9];
 940         } else {
 941                 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
 942                     ucp[0]);
 943                 return -1;
 944         }
 945
 946         /* Check if the whole packet is in buffer. */
 947         if (buffer_len(b) <
 948             12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
 949                 return 0;
 950
 951         /* Check if authentication protocol matches. */
 952         if (proto_len != strlen(x11_saved_proto) ||
 953             memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
 954                 debug2("X11 connection uses different authentication protocol.");
 955                 return -1;
 956         }
 957         /* Check if authentication data matches our fake data. */
 958         if (data_len != x11_fake_data_len ||
 959             timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
 960                 x11_fake_data, x11_fake_data_len) != 0) {
 961                 debug2("X11 auth data does not match fake data.");
 962                 return -1;
 963         }
 964         /* Check fake data length */
 965         if (x11_fake_data_len != x11_saved_data_len) {
 966                 error("X11 fake_data_len %d != saved_data_len %d",
 967                     x11_fake_data_len, x11_saved_data_len);
 968                 return -1;
 969         }
 970         /*
 971          * Received authentication protocol and data match
 972          * our fake data. Substitute the fake data with real
 973          * data.
 974          */
 975         memcpy(ucp + 12 + ((proto_len + 3) & ~3),
 976             x11_saved_data, x11_saved_data_len);
 977         return 1;
 978 }
 979
 980 static void
 981 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
 982 {
 983         int ret = x11_open_helper(&c->output);
 984
 985         if (ret == 1) {
 986                 /* Start normal processing for the channel. */
 987                 c->type = SSH_CHANNEL_OPEN;
 988                 channel_pre_open_13(c, readset, writeset);
 989         } else if (ret == -1) {
 990                 /*
 991                  * We have received an X11 connection that has bad
 992                  * authentication information.
 993                  */
 994                 logit("X11 connection rejected because of wrong authentication.");
 995                 buffer_clear(&c->input);
 996                 buffer_clear(&c->output);
 997                 channel_close_fd(&c->sock);
 998                 c->sock = -1;
 999                 c->type = SSH_CHANNEL_CLOSED;
1000                 packet_start(SSH_MSG_CHANNEL_CLOSE);
1001                 packet_put_int(c->remote_id);
1002                 packet_send();
1003         }
1004 }
1005
1006 static void
1007 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
1008 {
1009         int ret = x11_open_helper(&c->output);
1010
1011         /* c->force_drain = 1; */
1012
1013         if (ret == 1) {
1014                 c->type = SSH_CHANNEL_OPEN;
1015                 channel_pre_open(c, readset, writeset);
1016         } else if (ret == -1) {
1017                 logit("X11 connection rejected because of wrong authentication.");
1018                 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
1019                 chan_read_failed(c);
1020                 buffer_clear(&c->input);
1021                 chan_ibuf_empty(c);
1022                 buffer_clear(&c->output);
1023                 /* for proto v1, the peer will send an IEOF */
1024                 if (compat20)
1025                         chan_write_failed(c);
1026                 else
1027                         c->type = SSH_CHANNEL_OPEN;
1028                 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
1029         }
1030 }
1031
1032 static void
1033 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1034 {
1035         if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
1036             buffer_check_alloc(&c->input, CHAN_RBUF))
1037                 FD_SET(c->rfd, readset);
1038         if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1039                 /* clear buffer immediately (discard any partial packet) */
1040                 buffer_clear(&c->input);
1041                 chan_ibuf_empty(c);
1042                 /* Start output drain. XXX just kill chan? */
1043                 chan_rcvd_oclose(c);
1044         }
1045         if (c->ostate == CHAN_OUTPUT_OPEN ||
1046             c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1047                 if (buffer_len(&c->output) > 0)
1048                         FD_SET(c->wfd, writeset);
1049                 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1050                         chan_obuf_empty(c);
1051         }
1052 }
1053
1054 /* try to decode a socks4 header */
1055 /* ARGSUSED */
1056 static int
1057 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1058 {
1059         char *p, *host;
1060         u_int len, have, i, found, need;
1061         char username[256];
1062         struct {
1063                 u_int8_t version;
1064                 u_int8_t command;
1065                 u_int16_t dest_port;
1066                 struct in_addr dest_addr;
1067         } s4_req, s4_rsp;
1068
1069         debug2("channel %d: decode socks4", c->self);
1070
1071         have = buffer_len(&c->input);
1072         len = sizeof(s4_req);
1073         if (have < len)
1074                 return 0;
1075         p = (char *)buffer_ptr(&c->input);
1076
1077         need = 1;
1078         /* SOCKS4A uses an invalid IP address 0.0.0.x */
1079         if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1080                 debug2("channel %d: socks4a request", c->self);
1081                 /* ... and needs an extra string (the hostname) */
1082                 need = 2;
1083         }
1084         /* Check for terminating NUL on the string(s) */
1085         for (found = 0, i = len; i < have; i++) {
1086                 if (p[i] == '\0') {
1087                         found++;
1088                         if (found == need)
1089                                 break;
1090                 }
1091                 if (i > 1024) {
1092                         /* the peer is probably sending garbage */
1093                         debug("channel %d: decode socks4: too long",
1094                             c->self);
1095                         return -1;
1096                 }
1097         }
1098         if (found < need)
1099                 return 0;
1100         buffer_get(&c->input, (char *)&s4_req.version, 1);
1101         buffer_get(&c->input, (char *)&s4_req.command, 1);
1102         buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1103         buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1104         have = buffer_len(&c->input);
1105         p = (char *)buffer_ptr(&c->input);
1106         if (memchr(p, '\0', have) == NULL)
1107                 fatal("channel %d: decode socks4: user not nul terminated",
1108                     c->self);
1109         len = strlen(p);
1110         debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1111         len++;                                  /* trailing '\0' */
1112         if (len > have)
1113                 fatal("channel %d: decode socks4: len %d > have %d",
1114                     c->self, len, have);
1115         strlcpy(username, p, sizeof(username));
1116         buffer_consume(&c->input, len);
1117
1118         free(c->path);
1119         c->path = NULL;
1120         if (need == 1) {                        /* SOCKS4: one string */
1121                 host = inet_ntoa(s4_req.dest_addr);
1122                 c->path = xstrdup(host);
1123         } else {                                /* SOCKS4A: two strings */
1124                 have = buffer_len(&c->input);
1125                 p = (char *)buffer_ptr(&c->input);
1126                 len = strlen(p);
1127                 debug2("channel %d: decode socks4a: host %s/%d",
1128                     c->self, p, len);
1129                 len++;                          /* trailing '\0' */
1130                 if (len > have)
1131                         fatal("channel %d: decode socks4a: len %d > have %d",
1132                             c->self, len, have);
1133                 if (len > NI_MAXHOST) {
1134                         error("channel %d: hostname \"%.100s\" too long",
1135                             c->self, p);
1136                         return -1;
1137                 }
1138                 c->path = xstrdup(p);
1139                 buffer_consume(&c->input, len);
1140         }
1141         c->host_port = ntohs(s4_req.dest_port);
1142
1143         debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1144             c->self, c->path, c->host_port, s4_req.command);
1145
1146         if (s4_req.command != 1) {
1147                 debug("channel %d: cannot handle: %s cn %d",
1148                     c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1149                 return -1;
1150         }
1151         s4_rsp.version = 0;                     /* vn: 0 for reply */
1152         s4_rsp.command = 90;                    /* cd: req granted */
1153         s4_rsp.dest_port = 0;                   /* ignored */
1154         s4_rsp.dest_addr.s_addr = INADDR_ANY;   /* ignored */
1155         buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1156         return 1;
1157 }
1158
1159 /* try to decode a socks5 header */
1160 #define SSH_SOCKS5_AUTHDONE     0x1000
1161 #define SSH_SOCKS5_NOAUTH       0x00
1162 #define SSH_SOCKS5_IPV4         0x01
1163 #define SSH_SOCKS5_DOMAIN       0x03
1164 #define SSH_SOCKS5_IPV6         0x04
1165 #define SSH_SOCKS5_CONNECT      0x01
1166 #define SSH_SOCKS5_SUCCESS      0x00
1167
1168 /* ARGSUSED */
1169 static int
1170 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1171 {
1172         struct {
1173                 u_int8_t version;
1174                 u_int8_t command;
1175                 u_int8_t reserved;
1176                 u_int8_t atyp;
1177         } s5_req, s5_rsp;
1178         u_int16_t dest_port;
1179         char dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1180         u_char *p;
1181         u_int have, need, i, found, nmethods, addrlen, af;
1182
1183         debug2("channel %d: decode socks5", c->self);
1184         p = buffer_ptr(&c->input);
1185         if (p[0] != 0x05)
1186                 return -1;
1187         have = buffer_len(&c->input);
1188         if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1189                 /* format: ver | nmethods | methods */
1190                 if (have < 2)
1191                         return 0;
1192                 nmethods = p[1];
1193                 if (have < nmethods + 2)
1194                         return 0;
1195                 /* look for method: "NO AUTHENTICATION REQUIRED" */
1196                 for (found = 0, i = 2; i < nmethods + 2; i++) {
1197                         if (p[i] == SSH_SOCKS5_NOAUTH) {
1198                                 found = 1;
1199                                 break;
1200                         }
1201                 }
1202                 if (!found) {
1203                         debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1204                             c->self);
1205                         return -1;
1206                 }
1207                 buffer_consume(&c->input, nmethods + 2);
1208                 buffer_put_char(&c->output, 0x05);              /* version */
1209                 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1210                 FD_SET(c->sock, writeset);
1211                 c->flags |= SSH_SOCKS5_AUTHDONE;
1212                 debug2("channel %d: socks5 auth done", c->self);
1213                 return 0;                               /* need more */
1214         }
1215         debug2("channel %d: socks5 post auth", c->self);
1216         if (have < sizeof(s5_req)+1)
1217                 return 0;                       /* need more */
1218         memcpy(&s5_req, p, sizeof(s5_req));
1219         if (s5_req.version != 0x05 ||
1220             s5_req.command != SSH_SOCKS5_CONNECT ||
1221             s5_req.reserved != 0x00) {
1222                 debug2("channel %d: only socks5 connect supported", c->self);
1223                 return -1;
1224         }
1225         switch (s5_req.atyp){
1226         case SSH_SOCKS5_IPV4:
1227                 addrlen = 4;
1228                 af = AF_INET;
1229                 break;
1230         case SSH_SOCKS5_DOMAIN:
1231                 addrlen = p[sizeof(s5_req)];
1232                 af = -1;
1233                 break;
1234         case SSH_SOCKS5_IPV6:
1235                 addrlen = 16;
1236                 af = AF_INET6;
1237                 break;
1238         default:
1239                 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1240                 return -1;
1241         }
1242         need = sizeof(s5_req) + addrlen + 2;
1243         if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1244                 need++;
1245         if (have < need)
1246                 return 0;
1247         buffer_consume(&c->input, sizeof(s5_req));
1248         if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1249                 buffer_consume(&c->input, 1);    /* host string length */
1250         buffer_get(&c->input, &dest_addr, addrlen);
1251         buffer_get(&c->input, (char *)&dest_port, 2);
1252         dest_addr[addrlen] = '\0';
1253         free(c->path);
1254         c->path = NULL;
1255         if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1256                 if (addrlen >= NI_MAXHOST) {
1257                         error("channel %d: dynamic request: socks5 hostname "
1258                             "\"%.100s\" too long", c->self, dest_addr);
1259                         return -1;
1260                 }
1261                 c->path = xstrdup(dest_addr);
1262         } else {
1263                 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1264                         return -1;
1265                 c->path = xstrdup(ntop);
1266         }
1267         c->host_port = ntohs(dest_port);
1268
1269         debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1270             c->self, c->path, c->host_port, s5_req.command);
1271
1272         s5_rsp.version = 0x05;
1273         s5_rsp.command = SSH_SOCKS5_SUCCESS;
1274         s5_rsp.reserved = 0;                    /* ignored */
1275         s5_rsp.atyp = SSH_SOCKS5_IPV4;
1276         dest_port = 0;                          /* ignored */
1277
1278         buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1279         buffer_put_int(&c->output, ntohl(INADDR_ANY)); /* bind address */
1280         buffer_append(&c->output, &dest_port, sizeof(dest_port));
1281         return 1;
1282 }
1283
1284 Channel *
1285 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
1286     int in, int out)
1287 {
1288         Channel *c;
1289
1290         debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
1291             port_to_connect);
1292
1293         c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
1294             -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1295             0, "stdio-forward", /*nonblock*/0);
1296
1297         c->path = xstrdup(host_to_connect);
1298         c->host_port = port_to_connect;
1299         c->listening_port = 0;
1300         c->force_drain = 1;
1301
1302         channel_register_fds(c, in, out, -1, 0, 1, 0);
1303         port_open_helper(c, "direct-tcpip");
1304
1305         return c;
1306 }
1307
1308 /* dynamic port forwarding */
1309 static void
1310 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1311 {
1312         u_char *p;
1313         u_int have;
1314         int ret;
1315
1316         have = buffer_len(&c->input);
1317         debug2("channel %d: pre_dynamic: have %d", c->self, have);
1318         /* buffer_dump(&c->input); */
1319         /* check if the fixed size part of the packet is in buffer. */
1320         if (have < 3) {
1321                 /* need more */
1322                 FD_SET(c->sock, readset);
1323                 return;
1324         }
1325         /* try to guess the protocol */
1326         p = buffer_ptr(&c->input);
1327         switch (p[0]) {
1328         case 0x04:
1329                 ret = channel_decode_socks4(c, readset, writeset);
1330                 break;
1331         case 0x05:
1332                 ret = channel_decode_socks5(c, readset, writeset);
1333                 break;
1334         default:
1335                 ret = -1;
1336                 break;
1337         }
1338         if (ret < 0) {
1339                 chan_mark_dead(c);
1340         } else if (ret == 0) {
1341                 debug2("channel %d: pre_dynamic: need more", c->self);
1342                 /* need more */
1343                 FD_SET(c->sock, readset);
1344         } else {
1345                 /* switch to the next state */
1346                 c->type = SSH_CHANNEL_OPENING;
1347                 port_open_helper(c, "direct-tcpip");
1348         }
1349 }
1350
1351 /* This is our fake X11 server socket. */
1352 /* ARGSUSED */
1353 static void
1354 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1355 {
1356         Channel *nc;
1357         struct sockaddr_storage addr;
1358         int newsock, oerrno;
1359         socklen_t addrlen;
1360         char buf[16384], *remote_ipaddr;
1361         int remote_port;
1362
1363         if (FD_ISSET(c->sock, readset)) {
1364                 debug("X11 connection requested.");
1365                 addrlen = sizeof(addr);
1366                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1367                 if (c->single_connection) {
1368                         oerrno = errno;
1369                         debug2("single_connection: closing X11 listener.");
1370                         channel_close_fd(&c->sock);
1371                         chan_mark_dead(c);
1372                         errno = oerrno;
1373                 }
1374                 if (newsock < 0) {
1375                         if (errno != EINTR && errno != EWOULDBLOCK &&
1376                             errno != ECONNABORTED)
1377                                 error("accept: %.100s", strerror(errno));
1378                         if (errno == EMFILE || errno == ENFILE)
1379                                 c->notbefore = monotime() + 1;
1380                         return;
1381                 }
1382                 set_nodelay(newsock);
1383                 remote_ipaddr = get_peer_ipaddr(newsock);
1384                 remote_port = get_peer_port(newsock);
1385                 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1386                     remote_ipaddr, remote_port);
1387
1388                 nc = channel_new("accepted x11 socket",
1389                     SSH_CHANNEL_OPENING, newsock, newsock, -1,
1390                     c->local_window_max, c->local_maxpacket, 0, buf, 1);
1391                 if (compat20) {
1392                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1393                         packet_put_cstring("x11");
1394                         packet_put_int(nc->self);
1395                         packet_put_int(nc->local_window_max);
1396                         packet_put_int(nc->local_maxpacket);
1397                         /* originator ipaddr and port */
1398                         packet_put_cstring(remote_ipaddr);
1399                         if (datafellows & SSH_BUG_X11FWD) {
1400                                 debug2("ssh2 x11 bug compat mode");
1401                         } else {
1402                                 packet_put_int(remote_port);
1403                         }
1404                         packet_send();
1405                 } else {
1406                         packet_start(SSH_SMSG_X11_OPEN);
1407                         packet_put_int(nc->self);
1408                         if (packet_get_protocol_flags() &
1409                             SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1410                                 packet_put_cstring(buf);
1411                         packet_send();
1412                 }
1413                 free(remote_ipaddr);
1414         }
1415 }
1416
1417 static void
1418 port_open_helper(Channel *c, char *rtype)
1419 {
1420         char buf[1024];
1421         char *local_ipaddr = get_local_ipaddr(c->sock);
1422         int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock);
1423         char *remote_ipaddr = get_peer_ipaddr(c->sock);
1424         int remote_port = get_peer_port(c->sock);
1425
1426         if (remote_port == -1) {
1427                 /* Fake addr/port to appease peers that validate it (Tectia) */
1428                 free(remote_ipaddr);
1429                 remote_ipaddr = xstrdup("127.0.0.1");
1430                 remote_port = 65535;
1431         }
1432
1433         snprintf(buf, sizeof buf,
1434             "%s: listening port %d for %.100s port %d, "
1435             "connect from %.200s port %d to %.100s port %d",
1436             rtype, c->listening_port, c->path, c->host_port,
1437             remote_ipaddr, remote_port, local_ipaddr, local_port);
1438
1439         free(c->remote_name);
1440         c->remote_name = xstrdup(buf);
1441
1442         if (compat20) {
1443                 packet_start(SSH2_MSG_CHANNEL_OPEN);
1444                 packet_put_cstring(rtype);
1445                 packet_put_int(c->self);
1446                 packet_put_int(c->local_window_max);
1447                 packet_put_int(c->local_maxpacket);
1448                 if (strcmp(rtype, "direct-tcpip") == 0) {
1449                         /* target host, port */
1450                         packet_put_cstring(c->path);
1451                         packet_put_int(c->host_port);
1452                 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) {
1453                         /* target path */
1454                         packet_put_cstring(c->path);
1455                 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1456                         /* listen path */
1457                         packet_put_cstring(c->path);
1458                 } else {
1459                         /* listen address, port */
1460                         packet_put_cstring(c->path);
1461                         packet_put_int(local_port);
1462                 }
1463                 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1464                         /* reserved for future owner/mode info */
1465                         packet_put_cstring("");
1466                 } else {
1467                         /* originator host and port */
1468                         packet_put_cstring(remote_ipaddr);
1469                         packet_put_int((u_int)remote_port);
1470                 }
1471                 packet_send();
1472         } else {
1473                 packet_start(SSH_MSG_PORT_OPEN);
1474                 packet_put_int(c->self);
1475                 packet_put_cstring(c->path);
1476                 packet_put_int(c->host_port);
1477                 if (packet_get_protocol_flags() &
1478                     SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1479                         packet_put_cstring(c->remote_name);
1480                 packet_send();
1481         }
1482         free(remote_ipaddr);
1483         free(local_ipaddr);
1484 }
1485
1486 static void
1487 channel_set_reuseaddr(int fd)
1488 {
1489         int on = 1;
1490
1491         /*
1492          * Set socket options.
1493          * Allow local port reuse in TIME_WAIT.
1494          */
1495         if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1496                 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1497 }
1498
1499 void
1500 channel_set_x11_refuse_time(u_int refuse_time)
1501 {
1502         x11_refuse_time = refuse_time;
1503 }
1504
1505 /*
1506  * This socket is listening for connections to a forwarded TCP/IP port.
1507  */
1508 /* ARGSUSED */
1509 static void
1510 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1511 {
1512         Channel *nc;
1513         struct sockaddr_storage addr;
1514         int newsock, nextstate;
1515         socklen_t addrlen;
1516         char *rtype;
1517
1518         if (FD_ISSET(c->sock, readset)) {
1519                 debug("Connection to port %d forwarding "
1520                     "to %.100s port %d requested.",
1521                     c->listening_port, c->path, c->host_port);
1522
1523                 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1524                         nextstate = SSH_CHANNEL_OPENING;
1525                         rtype = "forwarded-tcpip";
1526                 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) {
1527                         nextstate = SSH_CHANNEL_OPENING;
1528                         rtype = "forwarded-streamlocal@openssh.com";
1529                 } else if (c->host_port == PORT_STREAMLOCAL) {
1530                         nextstate = SSH_CHANNEL_OPENING;
1531                         rtype = "direct-streamlocal@openssh.com";
1532                 } else if (c->host_port == 0) {
1533                         nextstate = SSH_CHANNEL_DYNAMIC;
1534                         rtype = "dynamic-tcpip";
1535                 } else {
1536                         nextstate = SSH_CHANNEL_OPENING;
1537                         rtype = "direct-tcpip";
1538                 }
1539
1540                 addrlen = sizeof(addr);
1541                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1542                 if (newsock < 0) {
1543                         if (errno != EINTR && errno != EWOULDBLOCK &&
1544                             errno != ECONNABORTED)
1545                                 error("accept: %.100s", strerror(errno));
1546                         if (errno == EMFILE || errno == ENFILE)
1547                                 c->notbefore = monotime() + 1;
1548                         return;
1549                 }
1550                 if (c->host_port != PORT_STREAMLOCAL)
1551                         set_nodelay(newsock);
1552                 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1553                     c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1554                 nc->listening_port = c->listening_port;
1555                 nc->host_port = c->host_port;
1556                 if (c->path != NULL)
1557                         nc->path = xstrdup(c->path);
1558
1559                 if (nextstate != SSH_CHANNEL_DYNAMIC)
1560                         port_open_helper(nc, rtype);
1561         }
1562 }
1563
1564 /*
1565  * This is the authentication agent socket listening for connections from
1566  * clients.
1567  */
1568 /* ARGSUSED */
1569 static void
1570 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1571 {
1572         Channel *nc;
1573         int newsock;
1574         struct sockaddr_storage addr;
1575         socklen_t addrlen;
1576
1577         if (FD_ISSET(c->sock, readset)) {
1578                 addrlen = sizeof(addr);
1579                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1580                 if (newsock < 0) {
1581                         error("accept from auth socket: %.100s",
1582                             strerror(errno));
1583                         if (errno == EMFILE || errno == ENFILE)
1584                                 c->notbefore = monotime() + 1;
1585                         return;
1586                 }
1587                 nc = channel_new("accepted auth socket",
1588                     SSH_CHANNEL_OPENING, newsock, newsock, -1,
1589                     c->local_window_max, c->local_maxpacket,
1590                     0, "accepted auth socket", 1);
1591                 if (compat20) {
1592                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1593                         packet_put_cstring("auth-agent@openssh.com");
1594                         packet_put_int(nc->self);
1595                         packet_put_int(c->local_window_max);
1596                         packet_put_int(c->local_maxpacket);
1597                 } else {
1598                         packet_start(SSH_SMSG_AGENT_OPEN);
1599                         packet_put_int(nc->self);
1600                 }
1601                 packet_send();
1602         }
1603 }
1604
1605 /* ARGSUSED */
1606 static void
1607 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1608 {
1609         int err = 0, sock;
1610         socklen_t sz = sizeof(err);
1611
1612         if (FD_ISSET(c->sock, writeset)) {
1613                 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1614                         err = errno;
1615                         error("getsockopt SO_ERROR failed");
1616                 }
1617                 if (err == 0) {
1618                         debug("channel %d: connected to %s port %d",
1619                             c->self, c->connect_ctx.host, c->connect_ctx.port);
1620                         channel_connect_ctx_free(&c->connect_ctx);
1621                         c->type = SSH_CHANNEL_OPEN;
1622                         if (compat20) {
1623                                 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1624                                 packet_put_int(c->remote_id);
1625                                 packet_put_int(c->self);
1626                                 packet_put_int(c->local_window);
1627                                 packet_put_int(c->local_maxpacket);
1628                         } else {
1629                                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1630                                 packet_put_int(c->remote_id);
1631                                 packet_put_int(c->self);
1632                         }
1633                 } else {
1634                         debug("channel %d: connection failed: %s",
1635                             c->self, strerror(err));
1636                         /* Try next address, if any */
1637                         if ((sock = connect_next(&c->connect_ctx)) > 0) {
1638                                 close(c->sock);
1639                                 c->sock = c->rfd = c->wfd = sock;
1640                                 channel_max_fd = channel_find_maxfd();
1641                                 return;
1642                         }
1643                         /* Exhausted all addresses */
1644                         error("connect_to %.100s port %d: failed.",
1645                             c->connect_ctx.host, c->connect_ctx.port);
1646                         channel_connect_ctx_free(&c->connect_ctx);
1647                         if (compat20) {
1648                                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1649                                 packet_put_int(c->remote_id);
1650                                 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1651                                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1652                                         packet_put_cstring(strerror(err));
1653                                         packet_put_cstring("");
1654                                 }
1655                         } else {
1656                                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1657                                 packet_put_int(c->remote_id);
1658                         }
1659                         chan_mark_dead(c);
1660                 }
1661                 packet_send();
1662         }
1663 }
1664
1665 /* ARGSUSED */
1666 static int
1667 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1668 {
1669         char buf[CHAN_RBUF];
1670         int len, force;
1671
1672         force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1673         if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1674                 errno = 0;
1675                 len = read(c->rfd, buf, sizeof(buf));
1676                 if (len < 0 && (errno == EINTR ||
1677                     ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1678                         return 1;
1679 #ifndef PTY_ZEROREAD
1680                 if (len <= 0) {
1681 #else
1682                 if ((!c->isatty && len <= 0) ||
1683                     (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1684 #endif
1685                         debug2("channel %d: read<=0 rfd %d len %d",
1686                             c->self, c->rfd, len);
1687                         if (c->type != SSH_CHANNEL_OPEN) {
1688                                 debug2("channel %d: not open", c->self);
1689                                 chan_mark_dead(c);
1690                                 return -1;
1691                         } else if (compat13) {
1692                                 buffer_clear(&c->output);
1693                                 c->type = SSH_CHANNEL_INPUT_DRAINING;
1694                                 debug2("channel %d: input draining.", c->self);
1695                         } else {
1696                                 chan_read_failed(c);
1697                         }
1698                         return -1;
1699                 }
1700                 if (c->input_filter != NULL) {
1701                         if (c->input_filter(c, buf, len) == -1) {
1702                                 debug2("channel %d: filter stops", c->self);
1703                                 chan_read_failed(c);
1704                         }
1705                 } else if (c->datagram) {
1706                         buffer_put_string(&c->input, buf, len);
1707                 } else {
1708                         buffer_append(&c->input, buf, len);
1709                 }
1710         }
1711         return 1;
1712 }
1713
1714 /* ARGSUSED */
1715 static int
1716 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1717 {
1718         struct termios tio;
1719         u_char *data = NULL, *buf;
1720         u_int dlen, olen = 0;
1721         int len;
1722
1723         /* Send buffered output data to the socket. */
1724         if (c->wfd != -1 &&
1725             FD_ISSET(c->wfd, writeset) &&
1726             buffer_len(&c->output) > 0) {
1727                 olen = buffer_len(&c->output);
1728                 if (c->output_filter != NULL) {
1729                         if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1730                                 debug2("channel %d: filter stops", c->self);
1731                                 if (c->type != SSH_CHANNEL_OPEN)
1732                                         chan_mark_dead(c);
1733                                 else
1734                                         chan_write_failed(c);
1735                                 return -1;
1736                         }
1737                 } else if (c->datagram) {
1738                         buf = data = buffer_get_string(&c->output, &dlen);
1739                 } else {
1740                         buf = data = buffer_ptr(&c->output);
1741                         dlen = buffer_len(&c->output);
1742                 }
1743
1744                 if (c->datagram) {
1745                         /* ignore truncated writes, datagrams might get lost */
1746                         len = write(c->wfd, buf, dlen);
1747                         free(data);
1748                         if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1749                             errno == EWOULDBLOCK))
1750                                 return 1;
1751                         if (len <= 0) {
1752                                 if (c->type != SSH_CHANNEL_OPEN)
1753                                         chan_mark_dead(c);
1754                                 else
1755                                         chan_write_failed(c);
1756                                 return -1;
1757                         }
1758                         goto out;
1759                 }
1760 #ifdef _AIX
1761                 /* XXX: Later AIX versions can't push as much data to tty */
1762                 if (compat20 && c->wfd_isatty)
1763                         dlen = MIN(dlen, 8*1024);
1764 #endif
1765
1766                 len = write(c->wfd, buf, dlen);
1767                 if (len < 0 &&
1768                     (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1769                         return 1;
1770                 if (len <= 0) {
1771                         if (c->type != SSH_CHANNEL_OPEN) {
1772                                 debug2("channel %d: not open", c->self);
1773                                 chan_mark_dead(c);
1774                                 return -1;
1775                         } else if (compat13) {
1776                                 buffer_clear(&c->output);
1777                                 debug2("channel %d: input draining.", c->self);
1778                                 c->type = SSH_CHANNEL_INPUT_DRAINING;
1779                         } else {
1780                                 chan_write_failed(c);
1781                         }
1782                         return -1;
1783                 }
1784 #ifndef BROKEN_TCGETATTR_ICANON
1785                 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1786                         if (tcgetattr(c->wfd, &tio) == 0 &&
1787                             !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1788                                 /*
1789                                  * Simulate echo to reduce the impact of
1790                                  * traffic analysis. We need to match the
1791                                  * size of a SSH2_MSG_CHANNEL_DATA message
1792                                  * (4 byte channel id + buf)
1793                                  */
1794                                 packet_send_ignore(4 + len);
1795                                 packet_send();
1796                         }
1797                 }
1798 #endif
1799                 buffer_consume(&c->output, len);
1800         }
1801  out:
1802         if (compat20 && olen > 0)
1803                 c->local_consumed += olen - buffer_len(&c->output);
1804         return 1;
1805 }
1806
1807 static int
1808 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1809 {
1810         char buf[CHAN_RBUF];
1811         int len;
1812
1813 /** XXX handle drain efd, too */
1814         if (c->efd != -1) {
1815                 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1816                     FD_ISSET(c->efd, writeset) &&
1817                     buffer_len(&c->extended) > 0) {
1818                         len = write(c->efd, buffer_ptr(&c->extended),
1819                             buffer_len(&c->extended));
1820                         debug2("channel %d: written %d to efd %d",
1821                             c->self, len, c->efd);
1822                         if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1823                             errno == EWOULDBLOCK))
1824                                 return 1;
1825                         if (len <= 0) {
1826                                 debug2("channel %d: closing write-efd %d",
1827                                     c->self, c->efd);
1828                                 channel_close_fd(&c->efd);
1829                         } else {
1830                                 buffer_consume(&c->extended, len);
1831                                 c->local_consumed += len;
1832                         }
1833                 } else if (c->efd != -1 &&
1834                     (c->extended_usage == CHAN_EXTENDED_READ ||
1835                     c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1836                     (c->detach_close || FD_ISSET(c->efd, readset))) {
1837                         len = read(c->efd, buf, sizeof(buf));
1838                         debug2("channel %d: read %d from efd %d",
1839                             c->self, len, c->efd);
1840                         if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1841                             errno == EWOULDBLOCK) && !c->detach_close)))
1842                                 return 1;
1843                         if (len <= 0) {
1844                                 debug2("channel %d: closing read-efd %d",
1845                                     c->self, c->efd);
1846                                 channel_close_fd(&c->efd);
1847                         } else {
1848                                 if (c->extended_usage == CHAN_EXTENDED_IGNORE) {
1849                                         debug3("channel %d: discard efd",
1850                                             c->self);
1851                                 } else
1852                                         buffer_append(&c->extended, buf, len);
1853                         }
1854                 }
1855         }
1856         return 1;
1857 }
1858
1859 static int
1860 channel_check_window(Channel *c)
1861 {
1862         if (c->type == SSH_CHANNEL_OPEN &&
1863             !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1864             ((c->local_window_max - c->local_window >
1865             c->local_maxpacket*3) ||
1866             c->local_window < c->local_window_max/2) &&
1867             c->local_consumed > 0) {
1868                 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1869                 packet_put_int(c->remote_id);
1870                 packet_put_int(c->local_consumed);
1871                 packet_send();
1872                 debug2("channel %d: window %d sent adjust %d",
1873                     c->self, c->local_window,
1874                     c->local_consumed);
1875                 c->local_window += c->local_consumed;
1876                 c->local_consumed = 0;
1877         }
1878         return 1;
1879 }
1880
1881 static void
1882 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1883 {
1884         channel_handle_rfd(c, readset, writeset);
1885         channel_handle_wfd(c, readset, writeset);
1886         if (!compat20)
1887                 return;
1888         channel_handle_efd(c, readset, writeset);
1889         channel_check_window(c);
1890 }
1891
1892 static u_int
1893 read_mux(Channel *c, u_int need)
1894 {
1895         char buf[CHAN_RBUF];
1896         int len;
1897         u_int rlen;
1898
1899         if (buffer_len(&c->input) < need) {
1900                 rlen = need - buffer_len(&c->input);
1901                 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF));
1902                 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1903                         return buffer_len(&c->input);
1904                 if (len <= 0) {
1905                         debug2("channel %d: ctl read<=0 rfd %d len %d",
1906                             c->self, c->rfd, len);
1907                         chan_read_failed(c);
1908                         return 0;
1909                 } else
1910                         buffer_append(&c->input, buf, len);
1911         }
1912         return buffer_len(&c->input);
1913 }
1914
1915 static void
1916 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1917 {
1918         u_int need;
1919         ssize_t len;
1920
1921         if (!compat20)
1922                 fatal("%s: entered with !compat20", __func__);
1923
1924         if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
1925             (c->istate == CHAN_INPUT_OPEN ||
1926             c->istate == CHAN_INPUT_WAIT_DRAIN)) {
1927                 /*
1928                  * Don't not read past the precise end of packets to
1929                  * avoid disrupting fd passing.
1930                  */
1931                 if (read_mux(c, 4) < 4) /* read header */
1932                         return;
1933                 need = get_u32(buffer_ptr(&c->input));
1934 #define CHANNEL_MUX_MAX_PACKET  (256 * 1024)
1935                 if (need > CHANNEL_MUX_MAX_PACKET) {
1936                         debug2("channel %d: packet too big %u > %u",
1937                             c->self, CHANNEL_MUX_MAX_PACKET, need);
1938                         chan_rcvd_oclose(c);
1939                         return;
1940                 }
1941                 if (read_mux(c, need + 4) < need + 4) /* read body */
1942                         return;
1943                 if (c->mux_rcb(c) != 0) {
1944                         debug("channel %d: mux_rcb failed", c->self);
1945                         chan_mark_dead(c);
1946                         return;
1947                 }
1948         }
1949
1950         if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) &&
1951             buffer_len(&c->output) > 0) {
1952                 len = write(c->wfd, buffer_ptr(&c->output),
1953                     buffer_len(&c->output));
1954                 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1955                         return;
1956                 if (len <= 0) {
1957                         chan_mark_dead(c);
1958                         return;
1959                 }
1960                 buffer_consume(&c->output, len);
1961         }
1962 }
1963
1964 static void
1965 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset)
1966 {
1967         Channel *nc;
1968         struct sockaddr_storage addr;
1969         socklen_t addrlen;
1970         int newsock;
1971         uid_t euid;
1972         gid_t egid;
1973
1974         if (!FD_ISSET(c->sock, readset))
1975                 return;
1976
1977         debug("multiplexing control connection");
1978
1979         /*
1980          * Accept connection on control socket
1981          */
1982         memset(&addr, 0, sizeof(addr));
1983         addrlen = sizeof(addr);
1984         if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
1985             &addrlen)) == -1) {
1986                 error("%s accept: %s", __func__, strerror(errno));
1987                 if (errno == EMFILE || errno == ENFILE)
1988                         c->notbefore = monotime() + 1;
1989                 return;
1990         }
1991
1992         if (getpeereid(newsock, &euid, &egid) < 0) {
1993                 error("%s getpeereid failed: %s", __func__,
1994                     strerror(errno));
1995                 close(newsock);
1996                 return;
1997         }
1998         if ((euid != 0) && (getuid() != euid)) {
1999                 error("multiplex uid mismatch: peer euid %u != uid %u",
2000                     (u_int)euid, (u_int)getuid());
2001                 close(newsock);
2002                 return;
2003         }
2004         nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT,
2005             newsock, newsock, -1, c->local_window_max,
2006             c->local_maxpacket, 0, "mux-control", 1);
2007         nc->mux_rcb = c->mux_rcb;
2008         debug3("%s: new mux channel %d fd %d", __func__,
2009             nc->self, nc->sock);
2010         /* establish state */
2011         nc->mux_rcb(nc);
2012         /* mux state transitions must not elicit protocol messages */
2013         nc->flags |= CHAN_LOCAL;
2014 }
2015
2016 /* ARGSUSED */
2017 static void
2018 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
2019 {
2020         int len;
2021
2022         /* Send buffered output data to the socket. */
2023         if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
2024                 len = write(c->sock, buffer_ptr(&c->output),
2025                             buffer_len(&c->output));
2026                 if (len <= 0)
2027                         buffer_clear(&c->output);
2028                 else
2029                         buffer_consume(&c->output, len);
2030         }
2031 }
2032
2033 static void
2034 channel_handler_init_20(void)
2035 {
2036         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open;
2037         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open;
2038         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
2039         channel_pre[SSH_CHANNEL_RPORT_LISTENER] =       &channel_pre_listener;
2040         channel_pre[SSH_CHANNEL_UNIX_LISTENER] =        &channel_pre_listener;
2041         channel_pre[SSH_CHANNEL_RUNIX_LISTENER] =       &channel_pre_listener;
2042         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
2043         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
2044         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
2045         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
2046         channel_pre[SSH_CHANNEL_MUX_LISTENER] =         &channel_pre_listener;
2047         channel_pre[SSH_CHANNEL_MUX_CLIENT] =           &channel_pre_mux_client;
2048
2049         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
2050         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
2051         channel_post[SSH_CHANNEL_RPORT_LISTENER] =      &channel_post_port_listener;
2052         channel_post[SSH_CHANNEL_UNIX_LISTENER] =       &channel_post_port_listener;
2053         channel_post[SSH_CHANNEL_RUNIX_LISTENER] =      &channel_post_port_listener;
2054         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
2055         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
2056         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
2057         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
2058         channel_post[SSH_CHANNEL_MUX_LISTENER] =        &channel_post_mux_listener;
2059         channel_post[SSH_CHANNEL_MUX_CLIENT] =          &channel_post_mux_client;
2060 }
2061
2062 static void
2063 channel_handler_init_13(void)
2064 {
2065         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open_13;
2066         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open_13;
2067         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
2068         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
2069         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
2070         channel_pre[SSH_CHANNEL_INPUT_DRAINING] =       &channel_pre_input_draining;
2071         channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] =      &channel_pre_output_draining;
2072         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
2073         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
2074
2075         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
2076         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
2077         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
2078         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
2079         channel_post[SSH_CHANNEL_OUTPUT_DRAINING] =     &channel_post_output_drain_13;
2080         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
2081         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
2082 }
2083
2084 static void
2085 channel_handler_init_15(void)
2086 {
2087         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open;
2088         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open;
2089         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
2090         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
2091         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
2092         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
2093         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
2094
2095         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
2096         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
2097         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
2098         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
2099         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
2100         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
2101 }
2102
2103 static void
2104 channel_handler_init(void)
2105 {
2106         int i;
2107
2108         for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
2109                 channel_pre[i] = NULL;
2110                 channel_post[i] = NULL;
2111         }
2112         if (compat20)
2113                 channel_handler_init_20();
2114         else if (compat13)
2115                 channel_handler_init_13();
2116         else
2117                 channel_handler_init_15();
2118 }
2119
2120 /* gc dead channels */
2121 static void
2122 channel_garbage_collect(Channel *c)
2123 {
2124         if (c == NULL)
2125                 return;
2126         if (c->detach_user != NULL) {
2127                 if (!chan_is_dead(c, c->detach_close))
2128                         return;
2129                 debug2("channel %d: gc: notify user", c->self);
2130                 c->detach_user(c->self, NULL);
2131                 /* if we still have a callback */
2132                 if (c->detach_user != NULL)
2133                         return;
2134                 debug2("channel %d: gc: user detached", c->self);
2135         }
2136         if (!chan_is_dead(c, 1))
2137                 return;
2138         debug2("channel %d: garbage collecting", c->self);
2139         channel_free(c);
2140 }
2141
2142 static void
2143 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset,
2144     time_t *unpause_secs)
2145 {
2146         static int did_init = 0;
2147         u_int i, oalloc;
2148         Channel *c;
2149         time_t now;
2150
2151         if (!did_init) {
2152                 channel_handler_init();
2153                 did_init = 1;
2154         }
2155         now = monotime();
2156         if (unpause_secs != NULL)
2157                 *unpause_secs = 0;
2158         for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
2159                 c = channels[i];
2160                 if (c == NULL)
2161                         continue;
2162                 if (c->delayed) {
2163                         if (ftab == channel_pre)
2164                                 c->delayed = 0;
2165                         else
2166                                 continue;
2167                 }
2168                 if (ftab[c->type] != NULL) {
2169                         /*
2170                          * Run handlers that are not paused.
2171                          */
2172                         if (c->notbefore <= now)
2173                                 (*ftab[c->type])(c, readset, writeset);
2174                         else if (unpause_secs != NULL) {
2175                                 /*
2176                                  * Collect the time that the earliest
2177                                  * channel comes off pause.
2178                                  */
2179                                 debug3("%s: chan %d: skip for %d more seconds",
2180                                     __func__, c->self,
2181                                     (int)(c->notbefore - now));
2182                                 if (*unpause_secs == 0 ||
2183                                     (c->notbefore - now) < *unpause_secs)
2184                                         *unpause_secs = c->notbefore - now;
2185                         }
2186                 }
2187                 channel_garbage_collect(c);
2188         }
2189         if (unpause_secs != NULL && *unpause_secs != 0)
2190                 debug3("%s: first channel unpauses in %d seconds",
2191                     __func__, (int)*unpause_secs);
2192 }
2193
2194 /*
2195  * Allocate/update select bitmasks and add any bits relevant to channels in
2196  * select bitmasks.
2197  */
2198 void
2199 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
2200     u_int *nallocp, time_t *minwait_secs, int rekeying)
2201 {
2202         u_int n, sz, nfdset;
2203
2204         n = MAX(*maxfdp, channel_max_fd);
2205
2206         nfdset = howmany(n+1, NFDBITS);
2207         /* Explicitly test here, because xrealloc isn't always called */
2208         if (nfdset && SIZE_MAX / nfdset < sizeof(fd_mask))
2209                 fatal("channel_prepare_select: max_fd (%d) is too large", n);
2210         sz = nfdset * sizeof(fd_mask);
2211
2212         /* perhaps check sz < nalloc/2 and shrink? */
2213         if (*readsetp == NULL || sz > *nallocp) {
2214                 *readsetp = xreallocarray(*readsetp, nfdset, sizeof(fd_mask));
2215                 *writesetp = xreallocarray(*writesetp, nfdset, sizeof(fd_mask));
2216                 *nallocp = sz;
2217         }
2218         *maxfdp = n;
2219         memset(*readsetp, 0, sz);
2220         memset(*writesetp, 0, sz);
2221
2222         if (!rekeying)
2223                 channel_handler(channel_pre, *readsetp, *writesetp,
2224                     minwait_secs);
2225 }
2226
2227 /*
2228  * After select, perform any appropriate operations for channels which have
2229  * events pending.
2230  */
2231 void
2232 channel_after_select(fd_set *readset, fd_set *writeset)
2233 {
2234         channel_handler(channel_post, readset, writeset, NULL);
2235 }
2236
2237
2238 /* If there is data to send to the connection, enqueue some of it now. */
2239 void
2240 channel_output_poll(void)
2241 {
2242         Channel *c;
2243         u_int i, len;
2244
2245         for (i = 0; i < channels_alloc; i++) {
2246                 c = channels[i];
2247                 if (c == NULL)
2248                         continue;
2249
2250                 /*
2251                  * We are only interested in channels that can have buffered
2252                  * incoming data.
2253                  */
2254                 if (compat13) {
2255                         if (c->type != SSH_CHANNEL_OPEN &&
2256                             c->type != SSH_CHANNEL_INPUT_DRAINING)
2257                                 continue;
2258                 } else {
2259                         if (c->type != SSH_CHANNEL_OPEN)
2260                                 continue;
2261                 }
2262                 if (compat20 &&
2263                     (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2264                         /* XXX is this true? */
2265                         debug3("channel %d: will not send data after close", c->self);
2266                         continue;
2267                 }
2268
2269                 /* Get the amount of buffered data for this channel. */
2270                 if ((c->istate == CHAN_INPUT_OPEN ||
2271                     c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2272                     (len = buffer_len(&c->input)) > 0) {
2273                         if (c->datagram) {
2274                                 if (len > 0) {
2275                                         u_char *data;
2276                                         u_int dlen;
2277
2278                                         data = buffer_get_string(&c->input,
2279                                             &dlen);
2280                                         if (dlen > c->remote_window ||
2281                                             dlen > c->remote_maxpacket) {
2282                                                 debug("channel %d: datagram "
2283                                                     "too big for channel",
2284                                                     c->self);
2285                                                 free(data);
2286                                                 continue;
2287                                         }
2288                                         packet_start(SSH2_MSG_CHANNEL_DATA);
2289                                         packet_put_int(c->remote_id);
2290                                         packet_put_string(data, dlen);
2291                                         packet_send();
2292                                         c->remote_window -= dlen;
2293                                         free(data);
2294                                 }
2295                                 continue;
2296                         }
2297                         /*
2298                          * Send some data for the other side over the secure
2299                          * connection.
2300                          */
2301                         if (compat20) {
2302                                 if (len > c->remote_window)
2303                                         len = c->remote_window;
2304                                 if (len > c->remote_maxpacket)
2305                                         len = c->remote_maxpacket;
2306                         } else {
2307                                 if (packet_is_interactive()) {
2308                                         if (len > 1024)
2309                                                 len = 512;
2310                                 } else {
2311                                         /* Keep the packets at reasonable size. */
2312                                         if (len > packet_get_maxsize()/2)
2313                                                 len = packet_get_maxsize()/2;
2314                                 }
2315                         }
2316                         if (len > 0) {
2317                                 packet_start(compat20 ?
2318                                     SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2319                                 packet_put_int(c->remote_id);
2320                                 packet_put_string(buffer_ptr(&c->input), len);
2321                                 packet_send();
2322                                 buffer_consume(&c->input, len);
2323                                 c->remote_window -= len;
2324                         }
2325                 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2326                         if (compat13)
2327                                 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2328                         /*
2329                          * input-buffer is empty and read-socket shutdown:
2330                          * tell peer, that we will not send more data: send IEOF.
2331                          * hack for extended data: delay EOF if EFD still in use.
2332                          */
2333                         if (CHANNEL_EFD_INPUT_ACTIVE(c))
2334                                 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2335                                     c->self, c->efd, buffer_len(&c->extended));
2336                         else
2337                                 chan_ibuf_empty(c);
2338                 }
2339                 /* Send extended data, i.e. stderr */
2340                 if (compat20 &&
2341                     !(c->flags & CHAN_EOF_SENT) &&
2342                     c->remote_window > 0 &&
2343                     (len = buffer_len(&c->extended)) > 0 &&
2344                     c->extended_usage == CHAN_EXTENDED_READ) {
2345                         debug2("channel %d: rwin %u elen %u euse %d",
2346                             c->self, c->remote_window, buffer_len(&c->extended),
2347                             c->extended_usage);
2348                         if (len > c->remote_window)
2349                                 len = c->remote_window;
2350                         if (len > c->remote_maxpacket)
2351                                 len = c->remote_maxpacket;
2352                         packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2353                         packet_put_int(c->remote_id);
2354                         packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2355                         packet_put_string(buffer_ptr(&c->extended), len);
2356                         packet_send();
2357                         buffer_consume(&c->extended, len);
2358                         c->remote_window -= len;
2359                         debug2("channel %d: sent ext data %d", c->self, len);
2360                 }
2361         }
2362 }
2363
2364
2365 /* -- protocol input */
2366
2367 /* ARGSUSED */
2368 int
2369 channel_input_data(int type, u_int32_t seq, void *ctxt)
2370 {
2371         int id;
2372         const u_char *data;
2373         u_int data_len, win_len;
2374         Channel *c;
2375
2376         /* Get the channel number and verify it. */
2377         id = packet_get_int();
2378         c = channel_lookup(id);
2379         if (c == NULL)
2380                 packet_disconnect("Received data for nonexistent channel %d.", id);
2381
2382         /* Ignore any data for non-open channels (might happen on close) */
2383         if (c->type != SSH_CHANNEL_OPEN &&
2384             c->type != SSH_CHANNEL_X11_OPEN)
2385                 return 0;
2386
2387         /* Get the data. */
2388         data = packet_get_string_ptr(&data_len);
2389         win_len = data_len;
2390         if (c->datagram)
2391                 win_len += 4;  /* string length header */
2392
2393         /*
2394          * Ignore data for protocol > 1.3 if output end is no longer open.
2395          * For protocol 2 the sending side is reducing its window as it sends
2396          * data, so we must 'fake' consumption of the data in order to ensure
2397          * that window updates are sent back.  Otherwise the connection might
2398          * deadlock.
2399          */
2400         if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2401                 if (compat20) {
2402                         c->local_window -= win_len;
2403                         c->local_consumed += win_len;
2404                 }
2405                 return 0;
2406         }
2407
2408         if (compat20) {
2409                 if (win_len > c->local_maxpacket) {
2410                         logit("channel %d: rcvd big packet %d, maxpack %d",
2411                             c->self, win_len, c->local_maxpacket);
2412                 }
2413                 if (win_len > c->local_window) {
2414                         logit("channel %d: rcvd too much data %d, win %d",
2415                             c->self, win_len, c->local_window);
2416                         return 0;
2417                 }
2418                 c->local_window -= win_len;
2419         }
2420         if (c->datagram)
2421                 buffer_put_string(&c->output, data, data_len);
2422         else
2423                 buffer_append(&c->output, data, data_len);
2424         packet_check_eom();
2425         return 0;
2426 }
2427
2428 /* ARGSUSED */
2429 int
2430 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2431 {
2432         int id;
2433         char *data;
2434         u_int data_len, tcode;
2435         Channel *c;
2436
2437         /* Get the channel number and verify it. */
2438         id = packet_get_int();
2439         c = channel_lookup(id);
2440
2441         if (c == NULL)
2442                 packet_disconnect("Received extended_data for bad channel %d.", id);
2443         if (c->type != SSH_CHANNEL_OPEN) {
2444                 logit("channel %d: ext data for non open", id);
2445                 return 0;
2446         }
2447         if (c->flags & CHAN_EOF_RCVD) {
2448                 if (datafellows & SSH_BUG_EXTEOF)
2449                         debug("channel %d: accepting ext data after eof", id);
2450                 else
2451                         packet_disconnect("Received extended_data after EOF "
2452                             "on channel %d.", id);
2453         }
2454         tcode = packet_get_int();
2455         if (c->efd == -1 ||
2456             c->extended_usage != CHAN_EXTENDED_WRITE ||
2457             tcode != SSH2_EXTENDED_DATA_STDERR) {
2458                 logit("channel %d: bad ext data", c->self);
2459                 return 0;
2460         }
2461         data = packet_get_string(&data_len);
2462         packet_check_eom();
2463         if (data_len > c->local_window) {
2464                 logit("channel %d: rcvd too much extended_data %d, win %d",
2465                     c->self, data_len, c->local_window);
2466                 free(data);
2467                 return 0;
2468         }
2469         debug2("channel %d: rcvd ext data %d", c->self, data_len);
2470         c->local_window -= data_len;
2471         buffer_append(&c->extended, data, data_len);
2472         free(data);
2473         return 0;
2474 }
2475
2476 /* ARGSUSED */
2477 int
2478 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2479 {
2480         int id;
2481         Channel *c;
2482
2483         id = packet_get_int();
2484         packet_check_eom();
2485         c = channel_lookup(id);
2486         if (c == NULL)
2487                 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2488         chan_rcvd_ieof(c);
2489
2490         /* XXX force input close */
2491         if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2492                 debug("channel %d: FORCE input drain", c->self);
2493                 c->istate = CHAN_INPUT_WAIT_DRAIN;
2494                 if (buffer_len(&c->input) == 0)
2495                         chan_ibuf_empty(c);
2496         }
2497         return 0;
2498 }
2499
2500 /* ARGSUSED */
2501 int
2502 channel_input_close(int type, u_int32_t seq, void *ctxt)
2503 {
2504         int id;
2505         Channel *c;
2506
2507         id = packet_get_int();
2508         packet_check_eom();
2509         c = channel_lookup(id);
2510         if (c == NULL)
2511                 packet_disconnect("Received close for nonexistent channel %d.", id);
2512
2513         /*
2514          * Send a confirmation that we have closed the channel and no more
2515          * data is coming for it.
2516          */
2517         packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2518         packet_put_int(c->remote_id);
2519         packet_send();
2520
2521         /*
2522          * If the channel is in closed state, we have sent a close request,
2523          * and the other side will eventually respond with a confirmation.
2524          * Thus, we cannot free the channel here, because then there would be
2525          * no-one to receive the confirmation.  The channel gets freed when
2526          * the confirmation arrives.
2527          */
2528         if (c->type != SSH_CHANNEL_CLOSED) {
2529                 /*
2530                  * Not a closed channel - mark it as draining, which will
2531                  * cause it to be freed later.
2532                  */
2533                 buffer_clear(&c->input);
2534                 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2535         }
2536         return 0;
2537 }
2538
2539 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2540 /* ARGSUSED */
2541 int
2542 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2543 {
2544         int id = packet_get_int();
2545         Channel *c = channel_lookup(id);
2546
2547         packet_check_eom();
2548         if (c == NULL)
2549                 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2550         chan_rcvd_oclose(c);
2551         return 0;
2552 }
2553
2554 /* ARGSUSED */
2555 int
2556 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2557 {
2558         int id = packet_get_int();
2559         Channel *c = channel_lookup(id);
2560
2561         packet_check_eom();
2562         if (c == NULL)
2563                 packet_disconnect("Received close confirmation for "
2564                     "out-of-range channel %d.", id);
2565         if (c->type != SSH_CHANNEL_CLOSED && c->type != SSH_CHANNEL_ABANDONED)
2566                 packet_disconnect("Received close confirmation for "
2567                     "non-closed channel %d (type %d).", id, c->type);
2568         channel_free(c);
2569         return 0;
2570 }
2571
2572 /* ARGSUSED */
2573 int
2574 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2575 {
2576         int id, remote_id;
2577         Channel *c;
2578
2579         id = packet_get_int();
2580         c = channel_lookup(id);
2581
2582         if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2583                 packet_disconnect("Received open confirmation for "
2584                     "non-opening channel %d.", id);
2585         remote_id = packet_get_int();
2586         /* Record the remote channel number and mark that the channel is now open. */
2587         c->remote_id = remote_id;
2588         c->type = SSH_CHANNEL_OPEN;
2589
2590         if (compat20) {
2591                 c->remote_window = packet_get_int();
2592                 c->remote_maxpacket = packet_get_int();
2593                 if (c->open_confirm) {
2594                         debug2("callback start");
2595                         c->open_confirm(c->self, 1, c->open_confirm_ctx);
2596                         debug2("callback done");
2597                 }
2598                 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2599                     c->remote_window, c->remote_maxpacket);
2600         }
2601         packet_check_eom();
2602         return 0;
2603 }
2604
2605 static char *
2606 reason2txt(int reason)
2607 {
2608         switch (reason) {
2609         case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2610                 return "administratively prohibited";
2611         case SSH2_OPEN_CONNECT_FAILED:
2612                 return "connect failed";
2613         case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2614                 return "unknown channel type";
2615         case SSH2_OPEN_RESOURCE_SHORTAGE:
2616                 return "resource shortage";
2617         }
2618         return "unknown reason";
2619 }
2620
2621 /* ARGSUSED */
2622 int
2623 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2624 {
2625         int id, reason;
2626         char *msg = NULL, *lang = NULL;
2627         Channel *c;
2628
2629         id = packet_get_int();
2630         c = channel_lookup(id);
2631
2632         if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2633                 packet_disconnect("Received open failure for "
2634                     "non-opening channel %d.", id);
2635         if (compat20) {
2636                 reason = packet_get_int();
2637                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2638                         msg  = packet_get_string(NULL);
2639                         lang = packet_get_string(NULL);
2640                 }
2641                 logit("channel %d: open failed: %s%s%s", id,
2642                     reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2643                 free(msg);
2644                 free(lang);
2645                 if (c->open_confirm) {
2646                         debug2("callback start");
2647                         c->open_confirm(c->self, 0, c->open_confirm_ctx);
2648                         debug2("callback done");
2649                 }
2650         }
2651         packet_check_eom();
2652         /* Schedule the channel for cleanup/deletion. */
2653         chan_mark_dead(c);
2654         return 0;
2655 }
2656
2657 /* ARGSUSED */
2658 int
2659 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2660 {
2661         Channel *c;
2662         int id;
2663         u_int adjust, tmp;
2664
2665         if (!compat20)
2666                 return 0;
2667
2668         /* Get the channel number and verify it. */
2669         id = packet_get_int();
2670         c = channel_lookup(id);
2671
2672         if (c == NULL) {
2673                 logit("Received window adjust for non-open channel %d.", id);
2674                 return 0;
2675         }
2676         adjust = packet_get_int();
2677         packet_check_eom();
2678         debug2("channel %d: rcvd adjust %u", id, adjust);
2679         if ((tmp = c->remote_window + adjust) < c->remote_window)
2680                 fatal("channel %d: adjust %u overflows remote window %u",
2681                     id, adjust, c->remote_window);
2682         c->remote_window = tmp;
2683         return 0;
2684 }
2685
2686 /* ARGSUSED */
2687 int
2688 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2689 {
2690         Channel *c = NULL;
2691         u_short host_port;
2692         char *host, *originator_string;
2693         int remote_id;
2694
2695         remote_id = packet_get_int();
2696         host = packet_get_string(NULL);
2697         host_port = packet_get_int();
2698
2699         if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2700                 originator_string = packet_get_string(NULL);
2701         } else {
2702                 originator_string = xstrdup("unknown (remote did not supply name)");
2703         }
2704         packet_check_eom();
2705         c = channel_connect_to_port(host, host_port,
2706             "connected socket", originator_string);
2707         free(originator_string);
2708         free(host);
2709         if (c == NULL) {
2710                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2711                 packet_put_int(remote_id);
2712                 packet_send();
2713         } else
2714                 c->remote_id = remote_id;
2715         return 0;
2716 }
2717
2718 /* ARGSUSED */
2719 int
2720 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2721 {
2722         Channel *c;
2723         struct channel_confirm *cc;
2724         int id;
2725
2726         /* Reset keepalive timeout */
2727         packet_set_alive_timeouts(0);
2728
2729         id = packet_get_int();
2730         packet_check_eom();
2731
2732         debug2("channel_input_status_confirm: type %d id %d", type, id);
2733
2734         if ((c = channel_lookup(id)) == NULL) {
2735                 logit("channel_input_status_confirm: %d: unknown", id);
2736                 return 0;
2737         }
2738         if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2739                 return 0;
2740         cc->cb(type, c, cc->ctx);
2741         TAILQ_REMOVE(&c->status_confirms, cc, entry);
2742         explicit_bzero(cc, sizeof(*cc));
2743         free(cc);
2744         return 0;
2745 }
2746
2747 /* -- tcp forwarding */
2748
2749 void
2750 channel_set_af(int af)
2751 {
2752         IPv4or6 = af;
2753 }
2754
2755
2756 /*
2757  * Determine whether or not a port forward listens to loopback, the
2758  * specified address or wildcard. On the client, a specified bind
2759  * address will always override gateway_ports. On the server, a
2760  * gateway_ports of 1 (``yes'') will override the client's specification
2761  * and force a wildcard bind, whereas a value of 2 (``clientspecified'')
2762  * will bind to whatever address the client asked for.
2763  *
2764  * Special-case listen_addrs are:
2765  *
2766  * "0.0.0.0"               -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2767  * "" (empty string), "*"  -> wildcard v4/v6
2768  * "localhost"             -> loopback v4/v6
2769  * "127.0.0.1" / "::1"     -> accepted even if gateway_ports isn't set
2770  */
2771 static const char *
2772 channel_fwd_bind_addr(const char *listen_addr, int *wildcardp,
2773     int is_client, struct ForwardOptions *fwd_opts)
2774 {
2775         const char *addr = NULL;
2776         int wildcard = 0;
2777
2778         if (listen_addr == NULL) {
2779                 /* No address specified: default to gateway_ports setting */
2780                 if (fwd_opts->gateway_ports)
2781                         wildcard = 1;
2782         } else if (fwd_opts->gateway_ports || is_client) {
2783                 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2784                     strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2785                     *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2786                     (!is_client && fwd_opts->gateway_ports == 1)) {
2787                         wildcard = 1;
2788                         /*
2789                          * Notify client if they requested a specific listen
2790                          * address and it was overridden.
2791                          */
2792                         if (*listen_addr != '\0' &&
2793                             strcmp(listen_addr, "0.0.0.0") != 0 &&
2794                             strcmp(listen_addr, "*") != 0) {
2795                                 packet_send_debug("Forwarding listen address "
2796                                     "\"%s\" overridden by server "
2797                                     "GatewayPorts", listen_addr);
2798                         }
2799                 } else if (strcmp(listen_addr, "localhost") != 0 ||
2800                     strcmp(listen_addr, "127.0.0.1") == 0 ||
2801                     strcmp(listen_addr, "::1") == 0) {
2802                         /* Accept localhost address when GatewayPorts=yes */
2803                         addr = listen_addr;
2804                 }
2805         } else if (strcmp(listen_addr, "127.0.0.1") == 0 ||
2806             strcmp(listen_addr, "::1") == 0) {
2807                 /*
2808                  * If a specific IPv4/IPv6 localhost address has been
2809                  * requested then accept it even if gateway_ports is in
2810                  * effect. This allows the client to prefer IPv4 or IPv6.
2811                  */
2812                 addr = listen_addr;
2813         }
2814         if (wildcardp != NULL)
2815                 *wildcardp = wildcard;
2816         return addr;
2817 }
2818
2819 static int
2820 channel_setup_fwd_listener_tcpip(int type, struct Forward *fwd,
2821     int *allocated_listen_port, struct ForwardOptions *fwd_opts)
2822 {
2823         Channel *c;
2824         int sock, r, success = 0, wildcard = 0, is_client;
2825         struct addrinfo hints, *ai, *aitop;
2826         const char *host, *addr;
2827         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2828         in_port_t *lport_p;
2829
2830         is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2831
2832         if (is_client && fwd->connect_path != NULL) {
2833                 host = fwd->connect_path;
2834         } else {
2835                 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2836                     fwd->listen_host : fwd->connect_host;
2837                 if (host == NULL) {
2838                         error("No forward host name.");
2839                         return 0;
2840                 }
2841                 if (strlen(host) >= NI_MAXHOST) {
2842                         error("Forward host name too long.");
2843                         return 0;
2844                 }
2845         }
2846
2847         /* Determine the bind address, cf. channel_fwd_bind_addr() comment */
2848         addr = channel_fwd_bind_addr(fwd->listen_host, &wildcard,
2849             is_client, fwd_opts);
2850         debug3("%s: type %d wildcard %d addr %s", __func__,
2851             type, wildcard, (addr == NULL) ? "NULL" : addr);
2852
2853         /*
2854          * getaddrinfo returns a loopback address if the hostname is
2855          * set to NULL and hints.ai_flags is not AI_PASSIVE
2856          */
2857         memset(&hints, 0, sizeof(hints));
2858         hints.ai_family = IPv4or6;
2859         hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2860         hints.ai_socktype = SOCK_STREAM;
2861         snprintf(strport, sizeof strport, "%d", fwd->listen_port);
2862         if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2863                 if (addr == NULL) {
2864                         /* This really shouldn't happen */
2865                         packet_disconnect("getaddrinfo: fatal error: %s",
2866                             ssh_gai_strerror(r));
2867                 } else {
2868                         error("%s: getaddrinfo(%.64s): %s", __func__, addr,
2869                             ssh_gai_strerror(r));
2870                 }
2871                 return 0;
2872         }
2873         if (allocated_listen_port != NULL)
2874                 *allocated_listen_port = 0;
2875         for (ai = aitop; ai; ai = ai->ai_next) {
2876                 switch (ai->ai_family) {
2877                 case AF_INET:
2878                         lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2879                             sin_port;
2880                         break;
2881                 case AF_INET6:
2882                         lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2883                             sin6_port;
2884                         break;
2885                 default:
2886                         continue;
2887                 }
2888                 /*
2889                  * If allocating a port for -R forwards, then use the
2890                  * same port for all address families.
2891                  */
2892                 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 &&
2893                     allocated_listen_port != NULL && *allocated_listen_port > 0)
2894                         *lport_p = htons(*allocated_listen_port);
2895
2896                 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2897                     strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2898                         error("%s: getnameinfo failed", __func__);
2899                         continue;
2900                 }
2901                 /* Create a port to listen for the host. */
2902                 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2903                 if (sock < 0) {
2904                         /* this is no error since kernel may not support ipv6 */
2905                         verbose("socket: %.100s", strerror(errno));
2906                         continue;
2907                 }
2908
2909                 channel_set_reuseaddr(sock);
2910                 if (ai->ai_family == AF_INET6)
2911                         sock_set_v6only(sock);
2912
2913                 debug("Local forwarding listening on %s port %s.",
2914                     ntop, strport);
2915
2916                 /* Bind the socket to the address. */
2917                 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2918                         /* address can be in use ipv6 address is already bound */
2919                         if (!ai->ai_next)
2920                                 error("bind: %.100s", strerror(errno));
2921                         else
2922                                 verbose("bind: %.100s", strerror(errno));
2923
2924                         close(sock);
2925                         continue;
2926                 }
2927                 /* Start listening for connections on the socket. */
2928                 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2929                         error("listen: %.100s", strerror(errno));
2930                         close(sock);
2931                         continue;
2932                 }
2933
2934                 /*
2935                  * fwd->listen_port == 0 requests a dynamically allocated port -
2936                  * record what we got.
2937                  */
2938                 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 &&
2939                     allocated_listen_port != NULL &&
2940                     *allocated_listen_port == 0) {
2941                         *allocated_listen_port = get_local_port(sock);
2942                         debug("Allocated listen port %d",
2943                             *allocated_listen_port);
2944                 }
2945
2946                 /* Allocate a channel number for the socket. */
2947                 c = channel_new("port listener", type, sock, sock, -1,
2948                     CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2949                     0, "port listener", 1);
2950                 c->path = xstrdup(host);
2951                 c->host_port = fwd->connect_port;
2952                 c->listening_addr = addr == NULL ? NULL : xstrdup(addr);
2953                 if (fwd->listen_port == 0 && allocated_listen_port != NULL &&
2954                     !(datafellows & SSH_BUG_DYNAMIC_RPORT))
2955                         c->listening_port = *allocated_listen_port;
2956                 else
2957                         c->listening_port = fwd->listen_port;
2958                 success = 1;
2959         }
2960         if (success == 0)
2961                 error("%s: cannot listen to port: %d", __func__,
2962                     fwd->listen_port);
2963         freeaddrinfo(aitop);
2964         return success;
2965 }
2966
2967 static int
2968 channel_setup_fwd_listener_streamlocal(int type, struct Forward *fwd,
2969     struct ForwardOptions *fwd_opts)
2970 {
2971         struct sockaddr_un sunaddr;
2972         const char *path;
2973         Channel *c;
2974         int port, sock;
2975         mode_t omask;
2976
2977         switch (type) {
2978         case SSH_CHANNEL_UNIX_LISTENER:
2979                 if (fwd->connect_path != NULL) {
2980                         if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) {
2981                                 error("Local connecting path too long: %s",
2982                                     fwd->connect_path);
2983                                 return 0;
2984                         }
2985                         path = fwd->connect_path;
2986                         port = PORT_STREAMLOCAL;
2987                 } else {
2988                         if (fwd->connect_host == NULL) {
2989                                 error("No forward host name.");
2990                                 return 0;
2991                         }
2992                         if (strlen(fwd->connect_host) >= NI_MAXHOST) {
2993                                 error("Forward host name too long.");
2994                                 return 0;
2995                         }
2996                         path = fwd->connect_host;
2997                         port = fwd->connect_port;
2998                 }
2999                 break;
3000         case SSH_CHANNEL_RUNIX_LISTENER:
3001                 path = fwd->listen_path;
3002                 port = PORT_STREAMLOCAL;
3003                 break;
3004         default:
3005                 error("%s: unexpected channel type %d", __func__, type);
3006                 return 0;
3007         }
3008
3009         if (fwd->listen_path == NULL) {
3010                 error("No forward path name.");
3011                 return 0;
3012         }
3013         if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) {
3014                 error("Local listening path too long: %s", fwd->listen_path);
3015                 return 0;
3016         }
3017
3018         debug3("%s: type %d path %s", __func__, type, fwd->listen_path);
3019
3020         /* Start a Unix domain listener. */
3021         omask = umask(fwd_opts->streamlocal_bind_mask);
3022         sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG,
3023             fwd_opts->streamlocal_bind_unlink);
3024         umask(omask);
3025         if (sock < 0)
3026                 return 0;
3027
3028         debug("Local forwarding listening on path %s.", fwd->listen_path);
3029
3030         /* Allocate a channel number for the socket. */
3031         c = channel_new("unix listener", type, sock, sock, -1,
3032             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
3033             0, "unix listener", 1);
3034         c->path = xstrdup(path);
3035         c->host_port = port;
3036         c->listening_port = PORT_STREAMLOCAL;
3037         c->listening_addr = xstrdup(fwd->listen_path);
3038         return 1;
3039 }
3040
3041 static int
3042 channel_cancel_rport_listener_tcpip(const char *host, u_short port)
3043 {
3044         u_int i;
3045         int found = 0;
3046
3047         for (i = 0; i < channels_alloc; i++) {
3048                 Channel *c = channels[i];
3049                 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER)
3050                         continue;
3051                 if (strcmp(c->path, host) == 0 && c->listening_port == port) {
3052                         debug2("%s: close channel %d", __func__, i);
3053                         channel_free(c);
3054                         found = 1;
3055                 }
3056         }
3057
3058         return (found);
3059 }
3060
3061 static int
3062 channel_cancel_rport_listener_streamlocal(const char *path)
3063 {
3064         u_int i;
3065         int found = 0;
3066
3067         for (i = 0; i < channels_alloc; i++) {
3068                 Channel *c = channels[i];
3069                 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER)
3070                         continue;
3071                 if (c->path == NULL)
3072                         continue;
3073                 if (strcmp(c->path, path) == 0) {
3074                         debug2("%s: close channel %d", __func__, i);
3075                         channel_free(c);
3076                         found = 1;
3077                 }
3078         }
3079
3080         return (found);
3081 }
3082
3083 int
3084 channel_cancel_rport_listener(struct Forward *fwd)
3085 {
3086         if (fwd->listen_path != NULL)
3087                 return channel_cancel_rport_listener_streamlocal(fwd->listen_path);
3088         else
3089                 return channel_cancel_rport_listener_tcpip(fwd->listen_host, fwd->listen_port);
3090 }
3091
3092 static int
3093 channel_cancel_lport_listener_tcpip(const char *lhost, u_short lport,
3094     int cport, struct ForwardOptions *fwd_opts)
3095 {
3096         u_int i;
3097         int found = 0;
3098         const char *addr = channel_fwd_bind_addr(lhost, NULL, 1, fwd_opts);
3099
3100         for (i = 0; i < channels_alloc; i++) {
3101                 Channel *c = channels[i];
3102                 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER)
3103                         continue;
3104                 if (c->listening_port != lport)
3105                         continue;
3106                 if (cport == CHANNEL_CANCEL_PORT_STATIC) {
3107                         /* skip dynamic forwardings */
3108                         if (c->host_port == 0)
3109                                 continue;
3110                 } else {
3111                         if (c->host_port != cport)
3112                                 continue;
3113                 }
3114                 if ((c->listening_addr == NULL && addr != NULL) ||
3115                     (c->listening_addr != NULL && addr == NULL))
3116                         continue;
3117                 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) {
3118                         debug2("%s: close channel %d", __func__, i);
3119                         channel_free(c);
3120                         found = 1;
3121                 }
3122         }
3123
3124         return (found);
3125 }
3126
3127 static int
3128 channel_cancel_lport_listener_streamlocal(const char *path)
3129 {
3130         u_int i;
3131         int found = 0;
3132
3133         if (path == NULL) {
3134                 error("%s: no path specified.", __func__);
3135                 return 0;
3136         }
3137
3138         for (i = 0; i < channels_alloc; i++) {
3139                 Channel *c = channels[i];
3140                 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER)
3141                         continue;
3142                 if (c->listening_addr == NULL)
3143                         continue;
3144                 if (strcmp(c->listening_addr, path) == 0) {
3145                         debug2("%s: close channel %d", __func__, i);
3146                         channel_free(c);
3147                         found = 1;
3148                 }
3149         }
3150
3151         return (found);
3152 }
3153
3154 int
3155 channel_cancel_lport_listener(struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts)
3156 {
3157         if (fwd->listen_path != NULL)
3158                 return channel_cancel_lport_listener_streamlocal(fwd->listen_path);
3159         else
3160                 return channel_cancel_lport_listener_tcpip(fwd->listen_host, fwd->listen_port, cport, fwd_opts);
3161 }
3162
3163 /* protocol local port fwd, used by ssh (and sshd in v1) */
3164 int
3165 channel_setup_local_fwd_listener(struct Forward *fwd, struct ForwardOptions *fwd_opts)
3166 {
3167         if (fwd->listen_path != NULL) {
3168                 return channel_setup_fwd_listener_streamlocal(
3169                     SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts);
3170         } else {
3171                 return channel_setup_fwd_listener_tcpip(SSH_CHANNEL_PORT_LISTENER,
3172                     fwd, NULL, fwd_opts);
3173         }
3174 }
3175
3176 /* protocol v2 remote port fwd, used by sshd */
3177 int
3178 channel_setup_remote_fwd_listener(struct Forward *fwd,
3179     int *allocated_listen_port, struct ForwardOptions *fwd_opts)
3180 {
3181         if (fwd->listen_path != NULL) {
3182                 return channel_setup_fwd_listener_streamlocal(
3183                     SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts);
3184         } else {
3185                 return channel_setup_fwd_listener_tcpip(
3186                     SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port,
3187                     fwd_opts);
3188         }
3189 }
3190
3191 /*
3192  * Translate the requested rfwd listen host to something usable for
3193  * this server.
3194  */
3195 static const char *
3196 channel_rfwd_bind_host(const char *listen_host)
3197 {
3198         if (listen_host == NULL) {
3199                 if (datafellows & SSH_BUG_RFWD_ADDR)
3200                         return "127.0.0.1";
3201                 else
3202                         return "localhost";
3203         } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) {
3204                 if (datafellows & SSH_BUG_RFWD_ADDR)
3205                         return "0.0.0.0";
3206                 else
3207                         return "";
3208         } else
3209                 return listen_host;
3210 }
3211
3212 /*
3213  * Initiate forwarding of connections to port "port" on remote host through
3214  * the secure channel to host:port from local side.
3215  * Returns handle (index) for updating the dynamic listen port with
3216  * channel_update_permitted_opens().
3217  */
3218 int
3219 channel_request_remote_forwarding(struct Forward *fwd)
3220 {
3221         int type, success = 0, idx = -1;
3222
3223         /* Send the forward request to the remote side. */
3224         if (compat20) {
3225                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
3226                 if (fwd->listen_path != NULL) {
3227                     packet_put_cstring("streamlocal-forward@openssh.com");
3228                     packet_put_char(1);         /* boolean: want reply */
3229                     packet_put_cstring(fwd->listen_path);
3230                 } else {
3231                     packet_put_cstring("tcpip-forward");
3232                     packet_put_char(1);         /* boolean: want reply */
3233                     packet_put_cstring(channel_rfwd_bind_host(fwd->listen_host));
3234                     packet_put_int(fwd->listen_port);
3235                 }
3236                 packet_send();
3237                 packet_write_wait();
3238                 /* Assume that server accepts the request */
3239                 success = 1;
3240         } else if (fwd->listen_path == NULL) {
3241                 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
3242                 packet_put_int(fwd->listen_port);
3243                 packet_put_cstring(fwd->connect_host);
3244                 packet_put_int(fwd->connect_port);
3245                 packet_send();
3246                 packet_write_wait();
3247
3248                 /* Wait for response from the remote side. */
3249                 type = packet_read();
3250                 switch (type) {
3251                 case SSH_SMSG_SUCCESS:
3252                         success = 1;
3253                         break;
3254                 case SSH_SMSG_FAILURE:
3255                         break;
3256                 default:
3257                         /* Unknown packet */
3258                         packet_disconnect("Protocol error for port forward request:"
3259                             "received packet type %d.", type);
3260                 }
3261         } else {
3262                 logit("Warning: Server does not support remote stream local forwarding.");
3263         }
3264         if (success) {
3265                 /* Record that connection to this host/port is permitted. */
3266                 permitted_opens = xreallocarray(permitted_opens,
3267                     num_permitted_opens + 1, sizeof(*permitted_opens));
3268                 idx = num_permitted_opens++;
3269                 if (fwd->connect_path != NULL) {
3270                         permitted_opens[idx].host_to_connect =
3271                             xstrdup(fwd->connect_path);
3272                         permitted_opens[idx].port_to_connect =
3273                             PORT_STREAMLOCAL;
3274                 } else {
3275                         permitted_opens[idx].host_to_connect =
3276                             xstrdup(fwd->connect_host);
3277                         permitted_opens[idx].port_to_connect =
3278                             fwd->connect_port;
3279                 }
3280                 if (fwd->listen_path != NULL) {
3281                         permitted_opens[idx].listen_host = NULL;
3282                         permitted_opens[idx].listen_path =
3283                             xstrdup(fwd->listen_path);
3284                         permitted_opens[idx].listen_port = PORT_STREAMLOCAL;
3285                 } else {
3286                         permitted_opens[idx].listen_host =
3287                             fwd->listen_host ? xstrdup(fwd->listen_host) : NULL;
3288                         permitted_opens[idx].listen_path = NULL;
3289                         permitted_opens[idx].listen_port = fwd->listen_port;
3290                 }
3291         }
3292         return (idx);
3293 }
3294
3295 static int
3296 open_match(ForwardPermission *allowed_open, const char *requestedhost,
3297     int requestedport)
3298 {
3299         if (allowed_open->host_to_connect == NULL)
3300                 return 0;
3301         if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT &&
3302             allowed_open->port_to_connect != requestedport)
3303                 return 0;
3304         if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 &&
3305             strcmp(allowed_open->host_to_connect, requestedhost) != 0)
3306                 return 0;
3307         return 1;
3308 }
3309
3310 /*
3311  * Note that in the listen host/port case
3312  * we don't support FWD_PERMIT_ANY_PORT and
3313  * need to translate between the configured-host (listen_host)
3314  * and what we've sent to the remote server (channel_rfwd_bind_host)
3315  */
3316 static int
3317 open_listen_match_tcpip(ForwardPermission *allowed_open,
3318     const char *requestedhost, u_short requestedport, int translate)
3319 {
3320         const char *allowed_host;
3321
3322         if (allowed_open->host_to_connect == NULL)
3323                 return 0;
3324         if (allowed_open->listen_port != requestedport)
3325                 return 0;
3326         if (!translate && allowed_open->listen_host == NULL &&
3327             requestedhost == NULL)
3328                 return 1;
3329         allowed_host = translate ?
3330             channel_rfwd_bind_host(allowed_open->listen_host) :
3331             allowed_open->listen_host;
3332         if (allowed_host == NULL ||
3333             strcmp(allowed_host, requestedhost) != 0)
3334                 return 0;
3335         return 1;
3336 }
3337
3338 static int
3339 open_listen_match_streamlocal(ForwardPermission *allowed_open,
3340     const char *requestedpath)
3341 {
3342         if (allowed_open->host_to_connect == NULL)
3343                 return 0;
3344         if (allowed_open->listen_port != PORT_STREAMLOCAL)
3345                 return 0;
3346         if (allowed_open->listen_path == NULL ||
3347             strcmp(allowed_open->listen_path, requestedpath) != 0)
3348                 return 0;
3349         return 1;
3350 }
3351
3352 /*
3353  * Request cancellation of remote forwarding of connection host:port from
3354  * local side.
3355  */
3356 static int
3357 channel_request_rforward_cancel_tcpip(const char *host, u_short port)
3358 {
3359         int i;
3360
3361         if (!compat20)
3362                 return -1;
3363
3364         for (i = 0; i < num_permitted_opens; i++) {
3365                 if (open_listen_match_tcpip(&permitted_opens[i], host, port, 0))
3366                         break;
3367         }
3368         if (i >= num_permitted_opens) {
3369                 debug("%s: requested forward not found", __func__);
3370                 return -1;
3371         }
3372         packet_start(SSH2_MSG_GLOBAL_REQUEST);
3373         packet_put_cstring("cancel-tcpip-forward");
3374         packet_put_char(0);
3375         packet_put_cstring(channel_rfwd_bind_host(host));
3376         packet_put_int(port);
3377         packet_send();
3378
3379         permitted_opens[i].listen_port = 0;
3380         permitted_opens[i].port_to_connect = 0;
3381         free(permitted_opens[i].host_to_connect);
3382         permitted_opens[i].host_to_connect = NULL;
3383         free(permitted_opens[i].listen_host);
3384         permitted_opens[i].listen_host = NULL;
3385         permitted_opens[i].listen_path = NULL;
3386
3387         return 0;
3388 }
3389
3390 /*
3391  * Request cancellation of remote forwarding of Unix domain socket
3392  * path from local side.
3393  */
3394 static int
3395 channel_request_rforward_cancel_streamlocal(const char *path)
3396 {
3397         int i;
3398
3399         if (!compat20)
3400                 return -1;
3401
3402         for (i = 0; i < num_permitted_opens; i++) {
3403                 if (open_listen_match_streamlocal(&permitted_opens[i], path))
3404                         break;
3405         }
3406         if (i >= num_permitted_opens) {
3407                 debug("%s: requested forward not found", __func__);
3408                 return -1;
3409         }
3410         packet_start(SSH2_MSG_GLOBAL_REQUEST);
3411         packet_put_cstring("cancel-streamlocal-forward@openssh.com");
3412         packet_put_char(0);
3413         packet_put_cstring(path);
3414         packet_send();
3415
3416         permitted_opens[i].listen_port = 0;
3417         permitted_opens[i].port_to_connect = 0;
3418         free(permitted_opens[i].host_to_connect);
3419         permitted_opens[i].host_to_connect = NULL;
3420         permitted_opens[i].listen_host = NULL;
3421         free(permitted_opens[i].listen_path);
3422         permitted_opens[i].listen_path = NULL;
3423
3424         return 0;
3425 }
3426
3427 /*
3428  * Request cancellation of remote forwarding of a connection from local side.
3429  */
3430 int
3431 channel_request_rforward_cancel(struct Forward *fwd)
3432 {
3433         if (fwd->listen_path != NULL) {
3434                 return (channel_request_rforward_cancel_streamlocal(
3435                     fwd->listen_path));
3436         } else {
3437                 return (channel_request_rforward_cancel_tcpip(fwd->listen_host,
3438                     fwd->listen_port ? fwd->listen_port : fwd->allocated_port));
3439         }
3440 }
3441
3442 /*
3443  * This is called after receiving CHANNEL_FORWARDING_REQUEST.  This initates
3444  * listening for the port, and sends back a success reply (or disconnect
3445  * message if there was an error).
3446  */
3447 int
3448 channel_input_port_forward_request(int is_root, struct ForwardOptions *fwd_opts)
3449 {
3450         int success = 0;
3451         struct Forward fwd;
3452
3453         /* Get arguments from the packet. */
3454         memset(&fwd, 0, sizeof(fwd));
3455         fwd.listen_port = packet_get_int();
3456         fwd.connect_host = packet_get_string(NULL);
3457         fwd.connect_port = packet_get_int();
3458
3459 #ifndef HAVE_CYGWIN
3460         /*
3461          * Check that an unprivileged user is not trying to forward a
3462          * privileged port.
3463          */
3464         if (fwd.listen_port < IPPORT_RESERVED && !is_root)
3465                 packet_disconnect(
3466                     "Requested forwarding of port %d but user is not root.",
3467                     fwd.listen_port);
3468         if (fwd.connect_port == 0)
3469                 packet_disconnect("Dynamic forwarding denied.");
3470 #endif
3471
3472         /* Initiate forwarding */
3473         success = channel_setup_local_fwd_listener(&fwd, fwd_opts);
3474
3475         /* Free the argument string. */
3476         free(fwd.connect_host);
3477
3478         return (success ? 0 : -1);
3479 }
3480
3481 /*
3482  * Permits opening to any host/port if permitted_opens[] is empty.  This is
3483  * usually called by the server, because the user could connect to any port
3484  * anyway, and the server has no way to know but to trust the client anyway.
3485  */
3486 void
3487 channel_permit_all_opens(void)
3488 {
3489         if (num_permitted_opens == 0)
3490                 all_opens_permitted = 1;
3491 }
3492
3493 void
3494 channel_add_permitted_opens(char *host, int port)
3495 {
3496         debug("allow port forwarding to host %s port %d", host, port);
3497
3498         permitted_opens = xreallocarray(permitted_opens,
3499             num_permitted_opens + 1, sizeof(*permitted_opens));
3500         permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
3501         permitted_opens[num_permitted_opens].port_to_connect = port;
3502         permitted_opens[num_permitted_opens].listen_host = NULL;
3503         permitted_opens[num_permitted_opens].listen_path = NULL;
3504         permitted_opens[num_permitted_opens].listen_port = 0;
3505         num_permitted_opens++;
3506
3507         all_opens_permitted = 0;
3508 }
3509
3510 /*
3511  * Update the listen port for a dynamic remote forward, after
3512  * the actual 'newport' has been allocated. If 'newport' < 0 is
3513  * passed then they entry will be invalidated.
3514  */
3515 void
3516 channel_update_permitted_opens(int idx, int newport)
3517 {
3518         if (idx < 0 || idx >= num_permitted_opens) {
3519                 debug("channel_update_permitted_opens: index out of range:"
3520                     " %d num_permitted_opens %d", idx, num_permitted_opens);
3521                 return;
3522         }
3523         debug("%s allowed port %d for forwarding to host %s port %d",
3524             newport > 0 ? "Updating" : "Removing",
3525             newport,
3526             permitted_opens[idx].host_to_connect,
3527             permitted_opens[idx].port_to_connect);
3528         if (newport >= 0)  {
3529                 permitted_opens[idx].listen_port =
3530                     (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport;
3531         } else {
3532                 permitted_opens[idx].listen_port = 0;
3533                 permitted_opens[idx].port_to_connect = 0;
3534                 free(permitted_opens[idx].host_to_connect);
3535                 permitted_opens[idx].host_to_connect = NULL;
3536                 free(permitted_opens[idx].listen_host);
3537                 permitted_opens[idx].listen_host = NULL;
3538                 free(permitted_opens[idx].listen_path);
3539                 permitted_opens[idx].listen_path = NULL;
3540         }
3541 }
3542
3543 int
3544 channel_add_adm_permitted_opens(char *host, int port)
3545 {
3546         debug("config allows port forwarding to host %s port %d", host, port);
3547
3548         permitted_adm_opens = xreallocarray(permitted_adm_opens,
3549             num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens));
3550         permitted_adm_opens[num_adm_permitted_opens].host_to_connect
3551              = xstrdup(host);
3552         permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
3553         permitted_adm_opens[num_adm_permitted_opens].listen_host = NULL;
3554         permitted_adm_opens[num_adm_permitted_opens].listen_path = NULL;
3555         permitted_adm_opens[num_adm_permitted_opens].listen_port = 0;
3556         return ++num_adm_permitted_opens;
3557 }
3558
3559 void
3560 channel_disable_adm_local_opens(void)
3561 {
3562         channel_clear_adm_permitted_opens();
3563         permitted_adm_opens = xcalloc(sizeof(*permitted_adm_opens), 1);
3564         permitted_adm_opens[num_adm_permitted_opens].host_to_connect = NULL;
3565         num_adm_permitted_opens = 1;
3566 }
3567
3568 void
3569 channel_clear_permitted_opens(void)
3570 {
3571         int i;
3572
3573         for (i = 0; i < num_permitted_opens; i++) {
3574                 free(permitted_opens[i].host_to_connect);
3575                 free(permitted_opens[i].listen_host);
3576                 free(permitted_opens[i].listen_path);
3577         }
3578         free(permitted_opens);
3579         permitted_opens = NULL;
3580         num_permitted_opens = 0;
3581 }
3582
3583 void
3584 channel_clear_adm_permitted_opens(void)
3585 {
3586         int i;
3587
3588         for (i = 0; i < num_adm_permitted_opens; i++) {
3589                 free(permitted_adm_opens[i].host_to_connect);
3590                 free(permitted_adm_opens[i].listen_host);
3591                 free(permitted_adm_opens[i].listen_path);
3592         }
3593         free(permitted_adm_opens);
3594         permitted_adm_opens = NULL;
3595         num_adm_permitted_opens = 0;
3596 }
3597
3598 void
3599 channel_print_adm_permitted_opens(void)
3600 {
3601         int i;
3602
3603         printf("permitopen");
3604         if (num_adm_permitted_opens == 0) {
3605                 printf(" any\n");
3606                 return;
3607         }
3608         for (i = 0; i < num_adm_permitted_opens; i++)
3609                 if (permitted_adm_opens[i].host_to_connect == NULL)
3610                         printf(" none");
3611                 else
3612                         printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
3613                             permitted_adm_opens[i].port_to_connect);
3614         printf("\n");
3615 }
3616
3617 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */
3618 int
3619 permitopen_port(const char *p)
3620 {
3621         int port;
3622
3623         if (strcmp(p, "*") == 0)
3624                 return FWD_PERMIT_ANY_PORT;
3625         if ((port = a2port(p)) > 0)
3626                 return port;
3627         return -1;
3628 }
3629
3630 /* Try to start non-blocking connect to next host in cctx list */
3631 static int
3632 connect_next(struct channel_connect *cctx)
3633 {
3634         int sock, saved_errno;
3635         struct sockaddr_un *sunaddr;
3636         char ntop[NI_MAXHOST], strport[MAX(NI_MAXSERV,sizeof(sunaddr->sun_path))];
3637
3638         for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
3639                 switch (cctx->ai->ai_family) {
3640                 case AF_UNIX:
3641                         /* unix:pathname instead of host:port */
3642                         sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr;
3643                         strlcpy(ntop, "unix", sizeof(ntop));
3644                         strlcpy(strport, sunaddr->sun_path, sizeof(strport));
3645                         break;
3646                 case AF_INET:
3647                 case AF_INET6:
3648                         if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
3649                             ntop, sizeof(ntop), strport, sizeof(strport),
3650                             NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3651                                 error("connect_next: getnameinfo failed");
3652                                 continue;
3653                         }
3654                         break;
3655                 default:
3656                         continue;
3657                 }
3658                 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
3659                     cctx->ai->ai_protocol)) == -1) {
3660                         if (cctx->ai->ai_next == NULL)
3661                                 error("socket: %.100s", strerror(errno));
3662                         else
3663                                 verbose("socket: %.100s", strerror(errno));
3664                         continue;
3665                 }
3666                 if (set_nonblock(sock) == -1)
3667                         fatal("%s: set_nonblock(%d)", __func__, sock);
3668                 if (connect(sock, cctx->ai->ai_addr,
3669                     cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
3670                         debug("connect_next: host %.100s ([%.100s]:%s): "
3671                             "%.100s", cctx->host, ntop, strport,
3672                             strerror(errno));
3673                         saved_errno = errno;
3674                         close(sock);
3675                         errno = saved_errno;
3676                         continue;       /* fail -- try next */
3677                 }
3678                 if (cctx->ai->ai_family != AF_UNIX)
3679                         set_nodelay(sock);
3680                 debug("connect_next: host %.100s ([%.100s]:%s) "
3681                     "in progress, fd=%d", cctx->host, ntop, strport, sock);
3682                 cctx->ai = cctx->ai->ai_next;
3683                 return sock;
3684         }
3685         return -1;
3686 }
3687
3688 static void
3689 channel_connect_ctx_free(struct channel_connect *cctx)
3690 {
3691         free(cctx->host);
3692         if (cctx->aitop) {
3693                 if (cctx->aitop->ai_family == AF_UNIX)
3694                         free(cctx->aitop);
3695                 else
3696                         freeaddrinfo(cctx->aitop);
3697         }
3698         memset(cctx, 0, sizeof(*cctx));
3699 }
3700
3701 /* Return CONNECTING channel to remote host:port or local socket path */
3702 static Channel *
3703 connect_to(const char *name, int port, char *ctype, char *rname)
3704 {
3705         struct addrinfo hints;
3706         int gaierr;
3707         int sock = -1;
3708         char strport[NI_MAXSERV];
3709         struct channel_connect cctx;
3710         Channel *c;
3711
3712         memset(&cctx, 0, sizeof(cctx));
3713
3714         if (port == PORT_STREAMLOCAL) {
3715                 struct sockaddr_un *sunaddr;
3716                 struct addrinfo *ai;
3717
3718                 if (strlen(name) > sizeof(sunaddr->sun_path)) {
3719                         error("%.100s: %.100s", name, strerror(ENAMETOOLONG));
3720                         return (NULL);
3721                 }
3722
3723                 /*
3724                  * Fake up a struct addrinfo for AF_UNIX connections.
3725                  * channel_connect_ctx_free() must check ai_family
3726                  * and use free() not freeaddirinfo() for AF_UNIX.
3727                  */
3728                 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr));
3729                 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr));
3730                 ai->ai_addr = (struct sockaddr *)(ai + 1);
3731                 ai->ai_addrlen = sizeof(*sunaddr);
3732                 ai->ai_family = AF_UNIX;
3733                 ai->ai_socktype = SOCK_STREAM;
3734                 ai->ai_protocol = PF_UNSPEC;
3735                 sunaddr = (struct sockaddr_un *)ai->ai_addr;
3736                 sunaddr->sun_family = AF_UNIX;
3737                 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path));
3738                 cctx.aitop = ai;
3739         } else {
3740                 memset(&hints, 0, sizeof(hints));
3741                 hints.ai_family = IPv4or6;
3742                 hints.ai_socktype = SOCK_STREAM;
3743                 snprintf(strport, sizeof strport, "%d", port);
3744                 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx.aitop)) != 0) {
3745                         error("connect_to %.100s: unknown host (%s)", name,
3746                             ssh_gai_strerror(gaierr));
3747                         return NULL;
3748                 }
3749         }
3750
3751         cctx.host = xstrdup(name);
3752         cctx.port = port;
3753         cctx.ai = cctx.aitop;
3754
3755         if ((sock = connect_next(&cctx)) == -1) {
3756                 error("connect to %.100s port %d failed: %s",
3757                     name, port, strerror(errno));
3758                 channel_connect_ctx_free(&cctx);
3759                 return NULL;
3760         }
3761         c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3762             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3763         c->connect_ctx = cctx;
3764         return c;
3765 }
3766
3767 Channel *
3768 channel_connect_by_listen_address(const char *listen_host,
3769     u_short listen_port, char *ctype, char *rname)
3770 {
3771         int i;
3772
3773         for (i = 0; i < num_permitted_opens; i++) {
3774                 if (open_listen_match_tcpip(&permitted_opens[i], listen_host,
3775                     listen_port, 1)) {
3776                         return connect_to(
3777                             permitted_opens[i].host_to_connect,
3778                             permitted_opens[i].port_to_connect, ctype, rname);
3779                 }
3780         }
3781         error("WARNING: Server requests forwarding for unknown listen_port %d",
3782             listen_port);
3783         return NULL;
3784 }
3785
3786 Channel *
3787 channel_connect_by_listen_path(const char *path, char *ctype, char *rname)
3788 {
3789         int i;
3790
3791         for (i = 0; i < num_permitted_opens; i++) {
3792                 if (open_listen_match_streamlocal(&permitted_opens[i], path)) {
3793                         return connect_to(
3794                             permitted_opens[i].host_to_connect,
3795                             permitted_opens[i].port_to_connect, ctype, rname);
3796                 }
3797         }
3798         error("WARNING: Server requests forwarding for unknown path %.100s",
3799             path);
3800         return NULL;
3801 }
3802
3803 /* Check if connecting to that port is permitted and connect. */
3804 Channel *
3805 channel_connect_to_port(const char *host, u_short port, char *ctype, char *rname)
3806 {
3807         int i, permit, permit_adm = 1;
3808
3809         permit = all_opens_permitted;
3810         if (!permit) {
3811                 for (i = 0; i < num_permitted_opens; i++)
3812                         if (open_match(&permitted_opens[i], host, port)) {
3813                                 permit = 1;
3814                                 break;
3815                         }
3816         }
3817
3818         if (num_adm_permitted_opens > 0) {
3819                 permit_adm = 0;
3820                 for (i = 0; i < num_adm_permitted_opens; i++)
3821                         if (open_match(&permitted_adm_opens[i], host, port)) {
3822                                 permit_adm = 1;
3823                                 break;
3824                         }
3825         }
3826
3827         if (!permit || !permit_adm) {
3828                 logit("Received request to connect to host %.100s port %d, "
3829                     "but the request was denied.", host, port);
3830                 return NULL;
3831         }
3832         return connect_to(host, port, ctype, rname);
3833 }
3834
3835 /* Check if connecting to that path is permitted and connect. */
3836 Channel *
3837 channel_connect_to_path(const char *path, char *ctype, char *rname)
3838 {
3839         int i, permit, permit_adm = 1;
3840
3841         permit = all_opens_permitted;
3842         if (!permit) {
3843                 for (i = 0; i < num_permitted_opens; i++)
3844                         if (open_match(&permitted_opens[i], path, PORT_STREAMLOCAL)) {
3845                                 permit = 1;
3846                                 break;
3847                         }
3848         }
3849
3850         if (num_adm_permitted_opens > 0) {
3851                 permit_adm = 0;
3852                 for (i = 0; i < num_adm_permitted_opens; i++)
3853                         if (open_match(&permitted_adm_opens[i], path, PORT_STREAMLOCAL)) {
3854                                 permit_adm = 1;
3855                                 break;
3856                         }
3857         }
3858
3859         if (!permit || !permit_adm) {
3860                 logit("Received request to connect to path %.100s, "
3861                     "but the request was denied.", path);
3862                 return NULL;
3863         }
3864         return connect_to(path, PORT_STREAMLOCAL, ctype, rname);
3865 }
3866
3867 void
3868 channel_send_window_changes(void)
3869 {
3870         u_int i;
3871         struct winsize ws;
3872
3873         for (i = 0; i < channels_alloc; i++) {
3874                 if (channels[i] == NULL || !channels[i]->client_tty ||
3875                     channels[i]->type != SSH_CHANNEL_OPEN)
3876                         continue;
3877                 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3878                         continue;
3879                 channel_request_start(i, "window-change", 0);
3880                 packet_put_int((u_int)ws.ws_col);
3881                 packet_put_int((u_int)ws.ws_row);
3882                 packet_put_int((u_int)ws.ws_xpixel);
3883                 packet_put_int((u_int)ws.ws_ypixel);
3884                 packet_send();
3885         }
3886 }
3887
3888 /* -- X11 forwarding */
3889
3890 /*
3891  * Creates an internet domain socket for listening for X11 connections.
3892  * Returns 0 and a suitable display number for the DISPLAY variable
3893  * stored in display_numberp , or -1 if an error occurs.
3894  */
3895 int
3896 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3897     int single_connection, u_int *display_numberp, int **chanids)
3898 {
3899         Channel *nc = NULL;
3900         int display_number, sock;
3901         u_short port;
3902         struct addrinfo hints, *ai, *aitop;
3903         char strport[NI_MAXSERV];
3904         int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3905
3906         if (chanids == NULL)
3907                 return -1;
3908
3909         for (display_number = x11_display_offset;
3910             display_number < MAX_DISPLAYS;
3911             display_number++) {
3912                 port = 6000 + display_number;
3913                 memset(&hints, 0, sizeof(hints));
3914                 hints.ai_family = IPv4or6;
3915                 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3916                 hints.ai_socktype = SOCK_STREAM;
3917                 snprintf(strport, sizeof strport, "%d", port);
3918                 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3919                         error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3920                         return -1;
3921                 }
3922                 for (ai = aitop; ai; ai = ai->ai_next) {
3923                         if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3924                                 continue;
3925                         sock = socket(ai->ai_family, ai->ai_socktype,
3926                             ai->ai_protocol);
3927                         if (sock < 0) {
3928                                 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
3929 #ifdef EPFNOSUPPORT
3930                                     && (errno != EPFNOSUPPORT)
3931 #endif
3932                                     ) {
3933                                         error("socket: %.100s", strerror(errno));
3934                                         freeaddrinfo(aitop);
3935                                         return -1;
3936                                 } else {
3937                                         debug("x11_create_display_inet: Socket family %d not supported",
3938                                                  ai->ai_family);
3939                                         continue;
3940                                 }
3941                         }
3942                         if (ai->ai_family == AF_INET6)
3943                                 sock_set_v6only(sock);
3944                         if (x11_use_localhost)
3945                                 channel_set_reuseaddr(sock);
3946                         if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3947                                 debug2("bind port %d: %.100s", port, strerror(errno));
3948                                 close(sock);
3949
3950                                 for (n = 0; n < num_socks; n++) {
3951                                         close(socks[n]);
3952                                 }
3953                                 num_socks = 0;
3954                                 break;
3955                         }
3956                         socks[num_socks++] = sock;
3957                         if (num_socks == NUM_SOCKS)
3958                                 break;
3959                 }
3960                 freeaddrinfo(aitop);
3961                 if (num_socks > 0)
3962                         break;
3963         }
3964         if (display_number >= MAX_DISPLAYS) {
3965                 error("Failed to allocate internet-domain X11 display socket.");
3966                 return -1;
3967         }
3968         /* Start listening for connections on the socket. */
3969         for (n = 0; n < num_socks; n++) {
3970                 sock = socks[n];
3971                 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3972                         error("listen: %.100s", strerror(errno));
3973                         close(sock);
3974                         return -1;
3975                 }
3976         }
3977
3978         /* Allocate a channel for each socket. */
3979         *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3980         for (n = 0; n < num_socks; n++) {
3981                 sock = socks[n];
3982                 nc = channel_new("x11 listener",
3983                     SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3984                     CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3985                     0, "X11 inet listener", 1);
3986                 nc->single_connection = single_connection;
3987                 (*chanids)[n] = nc->self;
3988         }
3989         (*chanids)[n] = -1;
3990
3991         /* Return the display number for the DISPLAY environment variable. */
3992         *display_numberp = display_number;
3993         return (0);
3994 }
3995
3996 static int
3997 connect_local_xsocket_path(const char *pathname)
3998 {
3999         int sock;
4000         struct sockaddr_un addr;
4001
4002         sock = socket(AF_UNIX, SOCK_STREAM, 0);
4003         if (sock < 0)
4004                 error("socket: %.100s", strerror(errno));
4005         memset(&addr, 0, sizeof(addr));
4006         addr.sun_family = AF_UNIX;
4007         strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
4008         if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
4009                 return sock;
4010         close(sock);
4011         error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
4012         return -1;
4013 }
4014
4015 static int
4016 connect_local_xsocket(u_int dnr)
4017 {
4018         char buf[1024];
4019         snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
4020         return connect_local_xsocket_path(buf);
4021 }
4022
4023 int
4024 x11_connect_display(void)
4025 {
4026         u_int display_number;
4027         const char *display;
4028         char buf[1024], *cp;
4029         struct addrinfo hints, *ai, *aitop;
4030         char strport[NI_MAXSERV];
4031         int gaierr, sock = 0;
4032
4033         /* Try to open a socket for the local X server. */
4034         display = getenv("DISPLAY");
4035         if (!display) {
4036                 error("DISPLAY not set.");
4037                 return -1;
4038         }
4039         /*
4040          * Now we decode the value of the DISPLAY variable and make a
4041          * connection to the real X server.
4042          */
4043
4044         /* Check if the display is from launchd. */
4045 #ifdef __APPLE__
4046         if (strncmp(display, "/tmp/launch", 11) == 0) {
4047                 sock = connect_local_xsocket_path(display);
4048                 if (sock < 0)
4049                         return -1;
4050
4051                 /* OK, we now have a connection to the display. */
4052                 return sock;
4053         }
4054 #endif
4055         /*
4056          * Check if it is a unix domain socket.  Unix domain displays are in
4057          * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
4058          */
4059         if (strncmp(display, "unix:", 5) == 0 ||
4060             display[0] == ':') {
4061                 /* Connect to the unix domain socket. */
4062                 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
4063                         error("Could not parse display number from DISPLAY: %.100s",
4064                             display);
4065                         return -1;
4066                 }
4067                 /* Create a socket. */
4068                 sock = connect_local_xsocket(display_number);
4069                 if (sock < 0)
4070                         return -1;
4071
4072                 /* OK, we now have a connection to the display. */
4073                 return sock;
4074         }
4075         /*
4076          * Connect to an inet socket.  The DISPLAY value is supposedly
4077          * hostname:d[.s], where hostname may also be numeric IP address.
4078          */
4079         strlcpy(buf, display, sizeof(buf));
4080         cp = strchr(buf, ':');
4081         if (!cp) {
4082                 error("Could not find ':' in DISPLAY: %.100s", display);
4083                 return -1;
4084         }
4085         *cp = 0;
4086         /* buf now contains the host name.  But first we parse the display number. */
4087         if (sscanf(cp + 1, "%u", &display_number) != 1) {
4088                 error("Could not parse display number from DISPLAY: %.100s",
4089                     display);
4090                 return -1;
4091         }
4092
4093         /* Look up the host address */
4094         memset(&hints, 0, sizeof(hints));
4095         hints.ai_family = IPv4or6;
4096         hints.ai_socktype = SOCK_STREAM;
4097         snprintf(strport, sizeof strport, "%u", 6000 + display_number);
4098         if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
4099                 error("%.100s: unknown host. (%s)", buf,
4100                 ssh_gai_strerror(gaierr));
4101                 return -1;
4102         }
4103         for (ai = aitop; ai; ai = ai->ai_next) {
4104                 /* Create a socket. */
4105                 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
4106                 if (sock < 0) {
4107                         debug2("socket: %.100s", strerror(errno));
4108                         continue;
4109                 }
4110                 /* Connect it to the display. */
4111                 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
4112                         debug2("connect %.100s port %u: %.100s", buf,
4113                             6000 + display_number, strerror(errno));
4114                         close(sock);
4115                         continue;
4116                 }
4117                 /* Success */
4118                 break;
4119         }
4120         freeaddrinfo(aitop);
4121         if (!ai) {
4122                 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
4123                     strerror(errno));
4124                 return -1;
4125         }
4126         set_nodelay(sock);
4127         return sock;
4128 }
4129
4130 /*
4131  * This is called when SSH_SMSG_X11_OPEN is received.  The packet contains
4132  * the remote channel number.  We should do whatever we want, and respond
4133  * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
4134  */
4135
4136 /* ARGSUSED */
4137 int
4138 x11_input_open(int type, u_int32_t seq, void *ctxt)
4139 {
4140         Channel *c = NULL;
4141         int remote_id, sock = 0;
4142         char *remote_host;
4143
4144         debug("Received X11 open request.");
4145
4146         remote_id = packet_get_int();
4147
4148         if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
4149                 remote_host = packet_get_string(NULL);
4150         } else {
4151                 remote_host = xstrdup("unknown (remote did not supply name)");
4152         }
4153         packet_check_eom();
4154
4155         /* Obtain a connection to the real X display. */
4156         sock = x11_connect_display();
4157         if (sock != -1) {
4158                 /* Allocate a channel for this connection. */
4159                 c = channel_new("connected x11 socket",
4160                     SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
4161                     remote_host, 1);
4162                 c->remote_id = remote_id;
4163                 c->force_drain = 1;
4164         }
4165         free(remote_host);
4166         if (c == NULL) {
4167                 /* Send refusal to the remote host. */
4168                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
4169                 packet_put_int(remote_id);
4170         } else {
4171                 /* Send a confirmation to the remote host. */
4172                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
4173                 packet_put_int(remote_id);
4174                 packet_put_int(c->self);
4175         }
4176         packet_send();
4177         return 0;
4178 }
4179
4180 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
4181 /* ARGSUSED */
4182 int
4183 deny_input_open(int type, u_int32_t seq, void *ctxt)
4184 {
4185         int rchan = packet_get_int();
4186
4187         switch (type) {
4188         case SSH_SMSG_AGENT_OPEN:
4189                 error("Warning: ssh server tried agent forwarding.");
4190                 break;
4191         case SSH_SMSG_X11_OPEN:
4192                 error("Warning: ssh server tried X11 forwarding.");
4193                 break;
4194         default:
4195                 error("deny_input_open: type %d", type);
4196                 break;
4197         }
4198         error("Warning: this is probably a break-in attempt by a malicious server.");
4199         packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
4200         packet_put_int(rchan);
4201         packet_send();
4202         return 0;
4203 }
4204
4205 /*
4206  * Requests forwarding of X11 connections, generates fake authentication
4207  * data, and enables authentication spoofing.
4208  * This should be called in the client only.
4209  */
4210 void
4211 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
4212     const char *proto, const char *data, int want_reply)
4213 {
4214         u_int data_len = (u_int) strlen(data) / 2;
4215         u_int i, value;
4216         char *new_data;
4217         int screen_number;
4218         const char *cp;
4219         u_int32_t rnd = 0;
4220
4221         if (x11_saved_display == NULL)
4222                 x11_saved_display = xstrdup(disp);
4223         else if (strcmp(disp, x11_saved_display) != 0) {
4224                 error("x11_request_forwarding_with_spoofing: different "
4225                     "$DISPLAY already forwarded");
4226                 return;
4227         }
4228
4229         cp = strchr(disp, ':');
4230         if (cp)
4231                 cp = strchr(cp, '.');
4232         if (cp)
4233                 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
4234         else
4235                 screen_number = 0;
4236
4237         if (x11_saved_proto == NULL) {
4238                 /* Save protocol name. */
4239                 x11_saved_proto = xstrdup(proto);
4240                 /*
4241                  * Extract real authentication data and generate fake data
4242                  * of the same length.
4243                  */
4244                 x11_saved_data = xmalloc(data_len);
4245                 x11_fake_data = xmalloc(data_len);
4246                 for (i = 0; i < data_len; i++) {
4247                         if (sscanf(data + 2 * i, "%2x", &value) != 1)
4248                                 fatal("x11_request_forwarding: bad "
4249                                     "authentication data: %.100s", data);
4250                         if (i % 4 == 0)
4251                                 rnd = arc4random();
4252                         x11_saved_data[i] = value;
4253                         x11_fake_data[i] = rnd & 0xff;
4254                         rnd >>= 8;
4255                 }
4256                 x11_saved_data_len = data_len;
4257                 x11_fake_data_len = data_len;
4258         }
4259
4260         /* Convert the fake data into hex. */
4261         new_data = tohex(x11_fake_data, data_len);
4262
4263         /* Send the request packet. */
4264         if (compat20) {
4265                 channel_request_start(client_session_id, "x11-req", want_reply);
4266                 packet_put_char(0);     /* XXX bool single connection */
4267         } else {
4268                 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
4269         }
4270         packet_put_cstring(proto);
4271         packet_put_cstring(new_data);
4272         packet_put_int(screen_number);
4273         packet_send();
4274         packet_write_wait();
4275         free(new_data);
4276 }
4277
4278
4279 /* -- agent forwarding */
4280
4281 /* Sends a message to the server to request authentication fd forwarding. */
4282
4283 void
4284 auth_request_forwarding(void)
4285 {
4286         packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
4287         packet_send();
4288         packet_write_wait();
4289 }