crypto/openssh/channels.c

   1 /* $OpenBSD: channels.c,v 1.349 2016/02/05 13:28:19 naddy 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 /*
 142  * If this is true, all opens are permitted.  This is the case on the server
 143  * on which we have to trust the client anyway, and the user could do
 144  * anything after logging in anyway.
 145  */
 146 static int all_opens_permitted = 0;
 147
 148
 149 /* -- X11 forwarding */
 150
 151 /* Maximum number of fake X11 displays to try. */
 152 #define MAX_DISPLAYS  1000
 153
 154 /* Saved X11 local (client) display. */
 155 static char *x11_saved_display = NULL;
 156
 157 /* Saved X11 authentication protocol name. */
 158 static char *x11_saved_proto = NULL;
 159
 160 /* Saved X11 authentication data.  This is the real data. */
 161 static char *x11_saved_data = NULL;
 162 static u_int x11_saved_data_len = 0;
 163
 164 /* Deadline after which all X11 connections are refused */
 165 static u_int x11_refuse_time;
 166
 167 /*
 168  * Fake X11 authentication data.  This is what the server will be sending us;
 169  * we should replace any occurrences of this by the real data.
 170  */
 171 static u_char *x11_fake_data = NULL;
 172 static u_int x11_fake_data_len;
 173
 174
 175 /* -- agent forwarding */
 176
 177 #define NUM_SOCKS       10
 178
 179 /* AF_UNSPEC or AF_INET or AF_INET6 */
 180 static int IPv4or6 = AF_UNSPEC;
 181
 182 /* helper */
 183 static void port_open_helper(Channel *c, char *rtype);
 184
 185 /* non-blocking connect helpers */
 186 static int connect_next(struct channel_connect *);
 187 static void channel_connect_ctx_free(struct channel_connect *);
 188
 189 /* -- channel core */
 190
 191 Channel *
 192 channel_by_id(int id)
 193 {
 194         Channel *c;
 195
 196         if (id < 0 || (u_int)id >= channels_alloc) {
 197                 logit("channel_by_id: %d: bad id", id);
 198                 return NULL;
 199         }
 200         c = channels[id];
 201         if (c == NULL) {
 202                 logit("channel_by_id: %d: bad id: channel free", id);
 203                 return NULL;
 204         }
 205         return c;
 206 }
 207
 208 /*
 209  * Returns the channel if it is allowed to receive protocol messages.
 210  * Private channels, like listening sockets, may not receive messages.
 211  */
 212 Channel *
 213 channel_lookup(int id)
 214 {
 215         Channel *c;
 216
 217         if ((c = channel_by_id(id)) == NULL)
 218                 return (NULL);
 219
 220         switch (c->type) {
 221         case SSH_CHANNEL_X11_OPEN:
 222         case SSH_CHANNEL_LARVAL:
 223         case SSH_CHANNEL_CONNECTING:
 224         case SSH_CHANNEL_DYNAMIC:
 225         case SSH_CHANNEL_OPENING:
 226         case SSH_CHANNEL_OPEN:
 227         case SSH_CHANNEL_INPUT_DRAINING:
 228         case SSH_CHANNEL_OUTPUT_DRAINING:
 229         case SSH_CHANNEL_ABANDONED:
 230                 return (c);
 231         }
 232         logit("Non-public channel %d, type %d.", id, c->type);
 233         return (NULL);
 234 }
 235
 236 /*
 237  * Register filedescriptors for a channel, used when allocating a channel or
 238  * when the channel consumer/producer is ready, e.g. shell exec'd
 239  */
 240 static void
 241 channel_register_fds(Channel *c, int rfd, int wfd, int efd,
 242     int extusage, int nonblock, int is_tty)
 243 {
 244         /* Update the maximum file descriptor value. */
 245         channel_max_fd = MAX(channel_max_fd, rfd);
 246         channel_max_fd = MAX(channel_max_fd, wfd);
 247         channel_max_fd = MAX(channel_max_fd, efd);
 248
 249         if (rfd != -1)
 250                 fcntl(rfd, F_SETFD, FD_CLOEXEC);
 251         if (wfd != -1 && wfd != rfd)
 252                 fcntl(wfd, F_SETFD, FD_CLOEXEC);
 253         if (efd != -1 && efd != rfd && efd != wfd)
 254                 fcntl(efd, F_SETFD, FD_CLOEXEC);
 255
 256         c->rfd = rfd;
 257         c->wfd = wfd;
 258         c->sock = (rfd == wfd) ? rfd : -1;
 259         c->efd = efd;
 260         c->extended_usage = extusage;
 261
 262         if ((c->isatty = is_tty) != 0)
 263                 debug2("channel %d: rfd %d isatty", c->self, c->rfd);
 264 #ifdef _AIX
 265         /* XXX: Later AIX versions can't push as much data to tty */
 266         c->wfd_isatty = is_tty || isatty(c->wfd);
 267 #endif
 268
 269         /* enable nonblocking mode */
 270         if (nonblock) {
 271                 if (rfd != -1)
 272                         set_nonblock(rfd);
 273                 if (wfd != -1)
 274                         set_nonblock(wfd);
 275                 if (efd != -1)
 276                         set_nonblock(efd);
 277         }
 278 }
 279
 280 /*
 281  * Allocate a new channel object and set its type and socket. This will cause
 282  * remote_name to be freed.
 283  */
 284 Channel *
 285 channel_new(char *ctype, int type, int rfd, int wfd, int efd,
 286     u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
 287 {
 288         int found;
 289         u_int i;
 290         Channel *c;
 291
 292         /* Do initial allocation if this is the first call. */
 293         if (channels_alloc == 0) {
 294                 channels_alloc = 10;
 295                 channels = xcalloc(channels_alloc, sizeof(Channel *));
 296                 for (i = 0; i < channels_alloc; i++)
 297                         channels[i] = NULL;
 298         }
 299         /* Try to find a free slot where to put the new channel. */
 300         for (found = -1, i = 0; i < channels_alloc; i++)
 301                 if (channels[i] == NULL) {
 302                         /* Found a free slot. */
 303                         found = (int)i;
 304                         break;
 305                 }
 306         if (found < 0) {
 307                 /* There are no free slots.  Take last+1 slot and expand the array.  */
 308                 found = channels_alloc;
 309                 if (channels_alloc > 10000)
 310                         fatal("channel_new: internal error: channels_alloc %d "
 311                             "too big.", channels_alloc);
 312                 channels = xreallocarray(channels, channels_alloc + 10,
 313                     sizeof(Channel *));
 314                 channels_alloc += 10;
 315                 debug2("channel: expanding %d", channels_alloc);
 316                 for (i = found; i < channels_alloc; i++)
 317                         channels[i] = NULL;
 318         }
 319         /* Initialize and return new channel. */
 320         c = channels[found] = xcalloc(1, sizeof(Channel));
 321         buffer_init(&c->input);
 322         buffer_init(&c->output);
 323         buffer_init(&c->extended);
 324         c->path = NULL;
 325         c->listening_addr = NULL;
 326         c->listening_port = 0;
 327         c->ostate = CHAN_OUTPUT_OPEN;
 328         c->istate = CHAN_INPUT_OPEN;
 329         c->flags = 0;
 330         channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
 331         c->notbefore = 0;
 332         c->self = found;
 333         c->type = type;
 334         c->ctype = ctype;
 335         c->local_window = window;
 336         c->local_window_max = window;
 337         c->local_consumed = 0;
 338         c->local_maxpacket = maxpack;
 339         c->remote_id = -1;
 340         c->remote_name = xstrdup(remote_name);
 341         c->remote_window = 0;
 342         c->remote_maxpacket = 0;
 343         c->force_drain = 0;
 344         c->single_connection = 0;
 345         c->detach_user = NULL;
 346         c->detach_close = 0;
 347         c->open_confirm = NULL;
 348         c->open_confirm_ctx = NULL;
 349         c->input_filter = NULL;
 350         c->output_filter = NULL;
 351         c->filter_ctx = NULL;
 352         c->filter_cleanup = NULL;
 353         c->ctl_chan = -1;
 354         c->mux_rcb = NULL;
 355         c->mux_ctx = NULL;
 356         c->mux_pause = 0;
 357         c->delayed = 1;         /* prevent call to channel_post handler */
 358         TAILQ_INIT(&c->status_confirms);
 359         debug("channel %d: new [%s]", found, remote_name);
 360         return c;
 361 }
 362
 363 static int
 364 channel_find_maxfd(void)
 365 {
 366         u_int i;
 367         int max = 0;
 368         Channel *c;
 369
 370         for (i = 0; i < channels_alloc; i++) {
 371                 c = channels[i];
 372                 if (c != NULL) {
 373                         max = MAX(max, c->rfd);
 374                         max = MAX(max, c->wfd);
 375                         max = MAX(max, c->efd);
 376                 }
 377         }
 378         return max;
 379 }
 380
 381 int
 382 channel_close_fd(int *fdp)
 383 {
 384         int ret = 0, fd = *fdp;
 385
 386         if (fd != -1) {
 387                 ret = close(fd);
 388                 *fdp = -1;
 389                 if (fd == channel_max_fd)
 390                         channel_max_fd = channel_find_maxfd();
 391         }
 392         return ret;
 393 }
 394
 395 /* Close all channel fd/socket. */
 396 static void
 397 channel_close_fds(Channel *c)
 398 {
 399         channel_close_fd(&c->sock);
 400         channel_close_fd(&c->rfd);
 401         channel_close_fd(&c->wfd);
 402         channel_close_fd(&c->efd);
 403 }
 404
 405 /* Free the channel and close its fd/socket. */
 406 void
 407 channel_free(Channel *c)
 408 {
 409         char *s;
 410         u_int i, n;
 411         struct channel_confirm *cc;
 412
 413         for (n = 0, i = 0; i < channels_alloc; i++)
 414                 if (channels[i])
 415                         n++;
 416         debug("channel %d: free: %s, nchannels %u", c->self,
 417             c->remote_name ? c->remote_name : "???", n);
 418
 419         s = channel_open_message();
 420         debug3("channel %d: status: %s", c->self, s);
 421         free(s);
 422
 423         if (c->sock != -1)
 424                 shutdown(c->sock, SHUT_RDWR);
 425         channel_close_fds(c);
 426         buffer_free(&c->input);
 427         buffer_free(&c->output);
 428         buffer_free(&c->extended);
 429         free(c->remote_name);
 430         c->remote_name = NULL;
 431         free(c->path);
 432         c->path = NULL;
 433         free(c->listening_addr);
 434         c->listening_addr = NULL;
 435         while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
 436                 if (cc->abandon_cb != NULL)
 437                         cc->abandon_cb(c, cc->ctx);
 438                 TAILQ_REMOVE(&c->status_confirms, cc, entry);
 439                 explicit_bzero(cc, sizeof(*cc));
 440                 free(cc);
 441         }
 442         if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
 443                 c->filter_cleanup(c->self, c->filter_ctx);
 444         channels[c->self] = NULL;
 445         free(c);
 446 }
 447
 448 void
 449 channel_free_all(void)
 450 {
 451         u_int i;
 452
 453         for (i = 0; i < channels_alloc; i++)
 454                 if (channels[i] != NULL)
 455                         channel_free(channels[i]);
 456 }
 457
 458 /*
 459  * Closes the sockets/fds of all channels.  This is used to close extra file
 460  * descriptors after a fork.
 461  */
 462 void
 463 channel_close_all(void)
 464 {
 465         u_int i;
 466
 467         for (i = 0; i < channels_alloc; i++)
 468                 if (channels[i] != NULL)
 469                         channel_close_fds(channels[i]);
 470 }
 471
 472 /*
 473  * Stop listening to channels.
 474  */
 475 void
 476 channel_stop_listening(void)
 477 {
 478         u_int i;
 479         Channel *c;
 480
 481         for (i = 0; i < channels_alloc; i++) {
 482                 c = channels[i];
 483                 if (c != NULL) {
 484                         switch (c->type) {
 485                         case SSH_CHANNEL_AUTH_SOCKET:
 486                         case SSH_CHANNEL_PORT_LISTENER:
 487                         case SSH_CHANNEL_RPORT_LISTENER:
 488                         case SSH_CHANNEL_X11_LISTENER:
 489                         case SSH_CHANNEL_UNIX_LISTENER:
 490                         case SSH_CHANNEL_RUNIX_LISTENER:
 491                                 channel_close_fd(&c->sock);
 492                                 channel_free(c);
 493                                 break;
 494                         }
 495                 }
 496         }
 497 }
 498
 499 /*
 500  * Returns true if no channel has too much buffered data, and false if one or
 501  * more channel is overfull.
 502  */
 503 int
 504 channel_not_very_much_buffered_data(void)
 505 {
 506         u_int i;
 507         Channel *c;
 508
 509         for (i = 0; i < channels_alloc; i++) {
 510                 c = channels[i];
 511                 if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
 512 #if 0
 513                         if (!compat20 &&
 514                             buffer_len(&c->input) > packet_get_maxsize()) {
 515                                 debug2("channel %d: big input buffer %d",
 516                                     c->self, buffer_len(&c->input));
 517                                 return 0;
 518                         }
 519 #endif
 520                         if (buffer_len(&c->output) > packet_get_maxsize()) {
 521                                 debug2("channel %d: big output buffer %u > %u",
 522                                     c->self, buffer_len(&c->output),
 523                                     packet_get_maxsize());
 524                                 return 0;
 525                         }
 526                 }
 527         }
 528         return 1;
 529 }
 530
 531 /* Returns true if any channel is still open. */
 532 int
 533 channel_still_open(void)
 534 {
 535         u_int i;
 536         Channel *c;
 537
 538         for (i = 0; i < channels_alloc; i++) {
 539                 c = channels[i];
 540                 if (c == NULL)
 541                         continue;
 542                 switch (c->type) {
 543                 case SSH_CHANNEL_X11_LISTENER:
 544                 case SSH_CHANNEL_PORT_LISTENER:
 545                 case SSH_CHANNEL_RPORT_LISTENER:
 546                 case SSH_CHANNEL_MUX_LISTENER:
 547                 case SSH_CHANNEL_CLOSED:
 548                 case SSH_CHANNEL_AUTH_SOCKET:
 549                 case SSH_CHANNEL_DYNAMIC:
 550                 case SSH_CHANNEL_CONNECTING:
 551                 case SSH_CHANNEL_ZOMBIE:
 552                 case SSH_CHANNEL_ABANDONED:
 553                 case SSH_CHANNEL_UNIX_LISTENER:
 554                 case SSH_CHANNEL_RUNIX_LISTENER:
 555                         continue;
 556                 case SSH_CHANNEL_LARVAL:
 557                         if (!compat20)
 558                                 fatal("cannot happen: SSH_CHANNEL_LARVAL");
 559                         continue;
 560                 case SSH_CHANNEL_OPENING:
 561                 case SSH_CHANNEL_OPEN:
 562                 case SSH_CHANNEL_X11_OPEN:
 563                 case SSH_CHANNEL_MUX_CLIENT:
 564                         return 1;
 565                 case SSH_CHANNEL_INPUT_DRAINING:
 566                 case SSH_CHANNEL_OUTPUT_DRAINING:
 567                         if (!compat13)
 568                                 fatal("cannot happen: OUT_DRAIN");
 569                         return 1;
 570                 default:
 571                         fatal("channel_still_open: bad channel type %d", c->type);
 572                         /* NOTREACHED */
 573                 }
 574         }
 575         return 0;
 576 }
 577
 578 /* Returns the id of an open channel suitable for keepaliving */
 579 int
 580 channel_find_open(void)
 581 {
 582         u_int i;
 583         Channel *c;
 584
 585         for (i = 0; i < channels_alloc; i++) {
 586                 c = channels[i];
 587                 if (c == NULL || c->remote_id < 0)
 588                         continue;
 589                 switch (c->type) {
 590                 case SSH_CHANNEL_CLOSED:
 591                 case SSH_CHANNEL_DYNAMIC:
 592                 case SSH_CHANNEL_X11_LISTENER:
 593                 case SSH_CHANNEL_PORT_LISTENER:
 594                 case SSH_CHANNEL_RPORT_LISTENER:
 595                 case SSH_CHANNEL_MUX_LISTENER:
 596                 case SSH_CHANNEL_MUX_CLIENT:
 597                 case SSH_CHANNEL_OPENING:
 598                 case SSH_CHANNEL_CONNECTING:
 599                 case SSH_CHANNEL_ZOMBIE:
 600                 case SSH_CHANNEL_ABANDONED:
 601                 case SSH_CHANNEL_UNIX_LISTENER:
 602                 case SSH_CHANNEL_RUNIX_LISTENER:
 603                         continue;
 604                 case SSH_CHANNEL_LARVAL:
 605                 case SSH_CHANNEL_AUTH_SOCKET:
 606                 case SSH_CHANNEL_OPEN:
 607                 case SSH_CHANNEL_X11_OPEN:
 608                         return i;
 609                 case SSH_CHANNEL_INPUT_DRAINING:
 610                 case SSH_CHANNEL_OUTPUT_DRAINING:
 611                         if (!compat13)
 612                                 fatal("cannot happen: OUT_DRAIN");
 613                         return i;
 614                 default:
 615                         fatal("channel_find_open: bad channel type %d", c->type);
 616                         /* NOTREACHED */
 617                 }
 618         }
 619         return -1;
 620 }
 621
 622
 623 /*
 624  * Returns a message describing the currently open forwarded connections,
 625  * suitable for sending to the client.  The message contains crlf pairs for
 626  * newlines.
 627  */
 628 char *
 629 channel_open_message(void)
 630 {
 631         Buffer buffer;
 632         Channel *c;
 633         char buf[1024], *cp;
 634         u_int i;
 635
 636         buffer_init(&buffer);
 637         snprintf(buf, sizeof buf, "The following connections are open:\r\n");
 638         buffer_append(&buffer, buf, strlen(buf));
 639         for (i = 0; i < channels_alloc; i++) {
 640                 c = channels[i];
 641                 if (c == NULL)
 642                         continue;
 643                 switch (c->type) {
 644                 case SSH_CHANNEL_X11_LISTENER:
 645                 case SSH_CHANNEL_PORT_LISTENER:
 646                 case SSH_CHANNEL_RPORT_LISTENER:
 647                 case SSH_CHANNEL_CLOSED:
 648                 case SSH_CHANNEL_AUTH_SOCKET:
 649                 case SSH_CHANNEL_ZOMBIE:
 650                 case SSH_CHANNEL_ABANDONED:
 651                 case SSH_CHANNEL_MUX_CLIENT:
 652                 case SSH_CHANNEL_MUX_LISTENER:
 653                 case SSH_CHANNEL_UNIX_LISTENER:
 654                 case SSH_CHANNEL_RUNIX_LISTENER:
 655                         continue;
 656                 case SSH_CHANNEL_LARVAL:
 657                 case SSH_CHANNEL_OPENING:
 658                 case SSH_CHANNEL_CONNECTING:
 659                 case SSH_CHANNEL_DYNAMIC:
 660                 case SSH_CHANNEL_OPEN:
 661                 case SSH_CHANNEL_X11_OPEN:
 662                 case SSH_CHANNEL_INPUT_DRAINING:
 663                 case SSH_CHANNEL_OUTPUT_DRAINING:
 664                         snprintf(buf, sizeof buf,
 665                             "  #%d %.300s (t%d r%d i%u/%d o%u/%d fd %d/%d cc %d)\r\n",
 666                             c->self, c->remote_name,
 667                             c->type, c->remote_id,
 668                             c->istate, buffer_len(&c->input),
 669                             c->ostate, buffer_len(&c->output),
 670                             c->rfd, c->wfd, c->ctl_chan);
 671                         buffer_append(&buffer, buf, strlen(buf));
 672                         continue;
 673                 default:
 674                         fatal("channel_open_message: bad channel type %d", c->type);
 675                         /* NOTREACHED */
 676                 }
 677         }
 678         buffer_append(&buffer, "\0", 1);
 679         cp = xstrdup((char *)buffer_ptr(&buffer));
 680         buffer_free(&buffer);
 681         return cp;
 682 }
 683
 684 void
 685 channel_send_open(int id)
 686 {
 687         Channel *c = channel_lookup(id);
 688
 689         if (c == NULL) {
 690                 logit("channel_send_open: %d: bad id", id);
 691                 return;
 692         }
 693         debug2("channel %d: send open", id);
 694         packet_start(SSH2_MSG_CHANNEL_OPEN);
 695         packet_put_cstring(c->ctype);
 696         packet_put_int(c->self);
 697         packet_put_int(c->local_window);
 698         packet_put_int(c->local_maxpacket);
 699         packet_send();
 700 }
 701
 702 void
 703 channel_request_start(int id, char *service, int wantconfirm)
 704 {
 705         Channel *c = channel_lookup(id);
 706
 707         if (c == NULL) {
 708                 logit("channel_request_start: %d: unknown channel id", id);
 709                 return;
 710         }
 711         debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
 712         packet_start(SSH2_MSG_CHANNEL_REQUEST);
 713         packet_put_int(c->remote_id);
 714         packet_put_cstring(service);
 715         packet_put_char(wantconfirm);
 716 }
 717
 718 void
 719 channel_register_status_confirm(int id, channel_confirm_cb *cb,
 720     channel_confirm_abandon_cb *abandon_cb, void *ctx)
 721 {
 722         struct channel_confirm *cc;
 723         Channel *c;
 724
 725         if ((c = channel_lookup(id)) == NULL)
 726                 fatal("channel_register_expect: %d: bad id", id);
 727
 728         cc = xcalloc(1, sizeof(*cc));
 729         cc->cb = cb;
 730         cc->abandon_cb = abandon_cb;
 731         cc->ctx = ctx;
 732         TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
 733 }
 734
 735 void
 736 channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
 737 {
 738         Channel *c = channel_lookup(id);
 739
 740         if (c == NULL) {
 741                 logit("channel_register_open_confirm: %d: bad id", id);
 742                 return;
 743         }
 744         c->open_confirm = fn;
 745         c->open_confirm_ctx = ctx;
 746 }
 747
 748 void
 749 channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
 750 {
 751         Channel *c = channel_by_id(id);
 752
 753         if (c == NULL) {
 754                 logit("channel_register_cleanup: %d: bad id", id);
 755                 return;
 756         }
 757         c->detach_user = fn;
 758         c->detach_close = do_close;
 759 }
 760
 761 void
 762 channel_cancel_cleanup(int id)
 763 {
 764         Channel *c = channel_by_id(id);
 765
 766         if (c == NULL) {
 767                 logit("channel_cancel_cleanup: %d: bad id", id);
 768                 return;
 769         }
 770         c->detach_user = NULL;
 771         c->detach_close = 0;
 772 }
 773
 774 void
 775 channel_register_filter(int id, channel_infilter_fn *ifn,
 776     channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
 777 {
 778         Channel *c = channel_lookup(id);
 779
 780         if (c == NULL) {
 781                 logit("channel_register_filter: %d: bad id", id);
 782                 return;
 783         }
 784         c->input_filter = ifn;
 785         c->output_filter = ofn;
 786         c->filter_ctx = ctx;
 787         c->filter_cleanup = cfn;
 788 }
 789
 790 void
 791 channel_set_fds(int id, int rfd, int wfd, int efd,
 792     int extusage, int nonblock, int is_tty, u_int window_max)
 793 {
 794         Channel *c = channel_lookup(id);
 795
 796         if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
 797                 fatal("channel_activate for non-larval channel %d.", id);
 798         channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty);
 799         c->type = SSH_CHANNEL_OPEN;
 800         c->local_window = c->local_window_max = window_max;
 801         packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
 802         packet_put_int(c->remote_id);
 803         packet_put_int(c->local_window);
 804         packet_send();
 805 }
 806
 807 /*
 808  * 'channel_pre*' are called just before select() to add any bits relevant to
 809  * channels in the select bitmasks.
 810  */
 811 /*
 812  * 'channel_post*': perform any appropriate operations for channels which
 813  * have events pending.
 814  */
 815 typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset);
 816 chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
 817 chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
 818
 819 /* ARGSUSED */
 820 static void
 821 channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
 822 {
 823         FD_SET(c->sock, readset);
 824 }
 825
 826 /* ARGSUSED */
 827 static void
 828 channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset)
 829 {
 830         debug3("channel %d: waiting for connection", c->self);
 831         FD_SET(c->sock, writeset);
 832 }
 833
 834 static void
 835 channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset)
 836 {
 837         if (buffer_len(&c->input) < packet_get_maxsize())
 838                 FD_SET(c->sock, readset);
 839         if (buffer_len(&c->output) > 0)
 840                 FD_SET(c->sock, writeset);
 841 }
 842
 843 static void
 844 channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset)
 845 {
 846         u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
 847
 848         if (c->istate == CHAN_INPUT_OPEN &&
 849             limit > 0 &&
 850             buffer_len(&c->input) < limit &&
 851             buffer_check_alloc(&c->input, CHAN_RBUF))
 852                 FD_SET(c->rfd, readset);
 853         if (c->ostate == CHAN_OUTPUT_OPEN ||
 854             c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
 855                 if (buffer_len(&c->output) > 0) {
 856                         FD_SET(c->wfd, writeset);
 857                 } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
 858                         if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
 859                                 debug2("channel %d: obuf_empty delayed efd %d/(%d)",
 860                                     c->self, c->efd, buffer_len(&c->extended));
 861                         else
 862                                 chan_obuf_empty(c);
 863                 }
 864         }
 865         /** XXX check close conditions, too */
 866         if (compat20 && c->efd != -1 &&
 867             !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
 868                 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
 869                     buffer_len(&c->extended) > 0)
 870                         FD_SET(c->efd, writeset);
 871                 else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) &&
 872                     (c->extended_usage == CHAN_EXTENDED_READ ||
 873                     c->extended_usage == CHAN_EXTENDED_IGNORE) &&
 874                     buffer_len(&c->extended) < c->remote_window)
 875                         FD_SET(c->efd, readset);
 876         }
 877         /* XXX: What about efd? races? */
 878 }
 879
 880 /* ARGSUSED */
 881 static void
 882 channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset)
 883 {
 884         if (buffer_len(&c->input) == 0) {
 885                 packet_start(SSH_MSG_CHANNEL_CLOSE);
 886                 packet_put_int(c->remote_id);
 887                 packet_send();
 888                 c->type = SSH_CHANNEL_CLOSED;
 889                 debug2("channel %d: closing after input drain.", c->self);
 890         }
 891 }
 892
 893 /* ARGSUSED */
 894 static void
 895 channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset)
 896 {
 897         if (buffer_len(&c->output) == 0)
 898                 chan_mark_dead(c);
 899         else
 900                 FD_SET(c->sock, writeset);
 901 }
 902
 903 /*
 904  * This is a special state for X11 authentication spoofing.  An opened X11
 905  * connection (when authentication spoofing is being done) remains in this
 906  * state until the first packet has been completely read.  The authentication
 907  * data in that packet is then substituted by the real data if it matches the
 908  * fake data, and the channel is put into normal mode.
 909  * XXX All this happens at the client side.
 910  * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
 911  */
 912 static int
 913 x11_open_helper(Buffer *b)
 914 {
 915         u_char *ucp;
 916         u_int proto_len, data_len;
 917
 918         /* Is this being called after the refusal deadline? */
 919         if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) {
 920                 verbose("Rejected X11 connection after ForwardX11Timeout "
 921                     "expired");
 922                 return -1;
 923         }
 924
 925         /* Check if the fixed size part of the packet is in buffer. */
 926         if (buffer_len(b) < 12)
 927                 return 0;
 928
 929         /* Parse the lengths of variable-length fields. */
 930         ucp = buffer_ptr(b);
 931         if (ucp[0] == 0x42) {   /* Byte order MSB first. */
 932                 proto_len = 256 * ucp[6] + ucp[7];
 933                 data_len = 256 * ucp[8] + ucp[9];
 934         } else if (ucp[0] == 0x6c) {    /* Byte order LSB first. */
 935                 proto_len = ucp[6] + 256 * ucp[7];
 936                 data_len = ucp[8] + 256 * ucp[9];
 937         } else {
 938                 debug2("Initial X11 packet contains bad byte order byte: 0x%x",
 939                     ucp[0]);
 940                 return -1;
 941         }
 942
 943         /* Check if the whole packet is in buffer. */
 944         if (buffer_len(b) <
 945             12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
 946                 return 0;
 947
 948         /* Check if authentication protocol matches. */
 949         if (proto_len != strlen(x11_saved_proto) ||
 950             memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
 951                 debug2("X11 connection uses different authentication protocol.");
 952                 return -1;
 953         }
 954         /* Check if authentication data matches our fake data. */
 955         if (data_len != x11_fake_data_len ||
 956             timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3),
 957                 x11_fake_data, x11_fake_data_len) != 0) {
 958                 debug2("X11 auth data does not match fake data.");
 959                 return -1;
 960         }
 961         /* Check fake data length */
 962         if (x11_fake_data_len != x11_saved_data_len) {
 963                 error("X11 fake_data_len %d != saved_data_len %d",
 964                     x11_fake_data_len, x11_saved_data_len);
 965                 return -1;
 966         }
 967         /*
 968          * Received authentication protocol and data match
 969          * our fake data. Substitute the fake data with real
 970          * data.
 971          */
 972         memcpy(ucp + 12 + ((proto_len + 3) & ~3),
 973             x11_saved_data, x11_saved_data_len);
 974         return 1;
 975 }
 976
 977 static void
 978 channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset)
 979 {
 980         int ret = x11_open_helper(&c->output);
 981
 982         if (ret == 1) {
 983                 /* Start normal processing for the channel. */
 984                 c->type = SSH_CHANNEL_OPEN;
 985                 channel_pre_open_13(c, readset, writeset);
 986         } else if (ret == -1) {
 987                 /*
 988                  * We have received an X11 connection that has bad
 989                  * authentication information.
 990                  */
 991                 logit("X11 connection rejected because of wrong authentication.");
 992                 buffer_clear(&c->input);
 993                 buffer_clear(&c->output);
 994                 channel_close_fd(&c->sock);
 995                 c->sock = -1;
 996                 c->type = SSH_CHANNEL_CLOSED;
 997                 packet_start(SSH_MSG_CHANNEL_CLOSE);
 998                 packet_put_int(c->remote_id);
 999                 packet_send();
1000         }
1001 }
1002
1003 static void
1004 channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset)
1005 {
1006         int ret = x11_open_helper(&c->output);
1007
1008         /* c->force_drain = 1; */
1009
1010         if (ret == 1) {
1011                 c->type = SSH_CHANNEL_OPEN;
1012                 channel_pre_open(c, readset, writeset);
1013         } else if (ret == -1) {
1014                 logit("X11 connection rejected because of wrong authentication.");
1015                 debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
1016                 chan_read_failed(c);
1017                 buffer_clear(&c->input);
1018                 chan_ibuf_empty(c);
1019                 buffer_clear(&c->output);
1020                 /* for proto v1, the peer will send an IEOF */
1021                 if (compat20)
1022                         chan_write_failed(c);
1023                 else
1024                         c->type = SSH_CHANNEL_OPEN;
1025                 debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
1026         }
1027 }
1028
1029 static void
1030 channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1031 {
1032         if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
1033             buffer_check_alloc(&c->input, CHAN_RBUF))
1034                 FD_SET(c->rfd, readset);
1035         if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
1036                 /* clear buffer immediately (discard any partial packet) */
1037                 buffer_clear(&c->input);
1038                 chan_ibuf_empty(c);
1039                 /* Start output drain. XXX just kill chan? */
1040                 chan_rcvd_oclose(c);
1041         }
1042         if (c->ostate == CHAN_OUTPUT_OPEN ||
1043             c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
1044                 if (buffer_len(&c->output) > 0)
1045                         FD_SET(c->wfd, writeset);
1046                 else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN)
1047                         chan_obuf_empty(c);
1048         }
1049 }
1050
1051 /* try to decode a socks4 header */
1052 /* ARGSUSED */
1053 static int
1054 channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
1055 {
1056         char *p, *host;
1057         u_int len, have, i, found, need;
1058         char username[256];
1059         struct {
1060                 u_int8_t version;
1061                 u_int8_t command;
1062                 u_int16_t dest_port;
1063                 struct in_addr dest_addr;
1064         } s4_req, s4_rsp;
1065
1066         debug2("channel %d: decode socks4", c->self);
1067
1068         have = buffer_len(&c->input);
1069         len = sizeof(s4_req);
1070         if (have < len)
1071                 return 0;
1072         p = (char *)buffer_ptr(&c->input);
1073
1074         need = 1;
1075         /* SOCKS4A uses an invalid IP address 0.0.0.x */
1076         if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
1077                 debug2("channel %d: socks4a request", c->self);
1078                 /* ... and needs an extra string (the hostname) */
1079                 need = 2;
1080         }
1081         /* Check for terminating NUL on the string(s) */
1082         for (found = 0, i = len; i < have; i++) {
1083                 if (p[i] == '\0') {
1084                         found++;
1085                         if (found == need)
1086                                 break;
1087                 }
1088                 if (i > 1024) {
1089                         /* the peer is probably sending garbage */
1090                         debug("channel %d: decode socks4: too long",
1091                             c->self);
1092                         return -1;
1093                 }
1094         }
1095         if (found < need)
1096                 return 0;
1097         buffer_get(&c->input, (char *)&s4_req.version, 1);
1098         buffer_get(&c->input, (char *)&s4_req.command, 1);
1099         buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
1100         buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
1101         have = buffer_len(&c->input);
1102         p = (char *)buffer_ptr(&c->input);
1103         if (memchr(p, '\0', have) == NULL)
1104                 fatal("channel %d: decode socks4: user not nul terminated",
1105                     c->self);
1106         len = strlen(p);
1107         debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
1108         len++;                                  /* trailing '\0' */
1109         if (len > have)
1110                 fatal("channel %d: decode socks4: len %d > have %d",
1111                     c->self, len, have);
1112         strlcpy(username, p, sizeof(username));
1113         buffer_consume(&c->input, len);
1114
1115         free(c->path);
1116         c->path = NULL;
1117         if (need == 1) {                        /* SOCKS4: one string */
1118                 host = inet_ntoa(s4_req.dest_addr);
1119                 c->path = xstrdup(host);
1120         } else {                                /* SOCKS4A: two strings */
1121                 have = buffer_len(&c->input);
1122                 p = (char *)buffer_ptr(&c->input);
1123                 len = strlen(p);
1124                 debug2("channel %d: decode socks4a: host %s/%d",
1125                     c->self, p, len);
1126                 len++;                          /* trailing '\0' */
1127                 if (len > have)
1128                         fatal("channel %d: decode socks4a: len %d > have %d",
1129                             c->self, len, have);
1130                 if (len > NI_MAXHOST) {
1131                         error("channel %d: hostname \"%.100s\" too long",
1132                             c->self, p);
1133                         return -1;
1134                 }
1135                 c->path = xstrdup(p);
1136                 buffer_consume(&c->input, len);
1137         }
1138         c->host_port = ntohs(s4_req.dest_port);
1139
1140         debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
1141             c->self, c->path, c->host_port, s4_req.command);
1142
1143         if (s4_req.command != 1) {
1144                 debug("channel %d: cannot handle: %s cn %d",
1145                     c->self, need == 1 ? "SOCKS4" : "SOCKS4A", s4_req.command);
1146                 return -1;
1147         }
1148         s4_rsp.version = 0;                     /* vn: 0 for reply */
1149         s4_rsp.command = 90;                    /* cd: req granted */
1150         s4_rsp.dest_port = 0;                   /* ignored */
1151         s4_rsp.dest_addr.s_addr = INADDR_ANY;   /* ignored */
1152         buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp));
1153         return 1;
1154 }
1155
1156 /* try to decode a socks5 header */
1157 #define SSH_SOCKS5_AUTHDONE     0x1000
1158 #define SSH_SOCKS5_NOAUTH       0x00
1159 #define SSH_SOCKS5_IPV4         0x01
1160 #define SSH_SOCKS5_DOMAIN       0x03
1161 #define SSH_SOCKS5_IPV6         0x04
1162 #define SSH_SOCKS5_CONNECT      0x01
1163 #define SSH_SOCKS5_SUCCESS      0x00
1164
1165 /* ARGSUSED */
1166 static int
1167 channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
1168 {
1169         struct {
1170                 u_int8_t version;
1171                 u_int8_t command;
1172                 u_int8_t reserved;
1173                 u_int8_t atyp;
1174         } s5_req, s5_rsp;
1175         u_int16_t dest_port;
1176         char dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
1177         u_char *p;
1178         u_int have, need, i, found, nmethods, addrlen, af;
1179
1180         debug2("channel %d: decode socks5", c->self);
1181         p = buffer_ptr(&c->input);
1182         if (p[0] != 0x05)
1183                 return -1;
1184         have = buffer_len(&c->input);
1185         if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
1186                 /* format: ver | nmethods | methods */
1187                 if (have < 2)
1188                         return 0;
1189                 nmethods = p[1];
1190                 if (have < nmethods + 2)
1191                         return 0;
1192                 /* look for method: "NO AUTHENTICATION REQUIRED" */
1193                 for (found = 0, i = 2; i < nmethods + 2; i++) {
1194                         if (p[i] == SSH_SOCKS5_NOAUTH) {
1195                                 found = 1;
1196                                 break;
1197                         }
1198                 }
1199                 if (!found) {
1200                         debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
1201                             c->self);
1202                         return -1;
1203                 }
1204                 buffer_consume(&c->input, nmethods + 2);
1205                 buffer_put_char(&c->output, 0x05);              /* version */
1206                 buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
1207                 FD_SET(c->sock, writeset);
1208                 c->flags |= SSH_SOCKS5_AUTHDONE;
1209                 debug2("channel %d: socks5 auth done", c->self);
1210                 return 0;                               /* need more */
1211         }
1212         debug2("channel %d: socks5 post auth", c->self);
1213         if (have < sizeof(s5_req)+1)
1214                 return 0;                       /* need more */
1215         memcpy(&s5_req, p, sizeof(s5_req));
1216         if (s5_req.version != 0x05 ||
1217             s5_req.command != SSH_SOCKS5_CONNECT ||
1218             s5_req.reserved != 0x00) {
1219                 debug2("channel %d: only socks5 connect supported", c->self);
1220                 return -1;
1221         }
1222         switch (s5_req.atyp){
1223         case SSH_SOCKS5_IPV4:
1224                 addrlen = 4;
1225                 af = AF_INET;
1226                 break;
1227         case SSH_SOCKS5_DOMAIN:
1228                 addrlen = p[sizeof(s5_req)];
1229                 af = -1;
1230                 break;
1231         case SSH_SOCKS5_IPV6:
1232                 addrlen = 16;
1233                 af = AF_INET6;
1234                 break;
1235         default:
1236                 debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
1237                 return -1;
1238         }
1239         need = sizeof(s5_req) + addrlen + 2;
1240         if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1241                 need++;
1242         if (have < need)
1243                 return 0;
1244         buffer_consume(&c->input, sizeof(s5_req));
1245         if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
1246                 buffer_consume(&c->input, 1);    /* host string length */
1247         buffer_get(&c->input, &dest_addr, addrlen);
1248         buffer_get(&c->input, (char *)&dest_port, 2);
1249         dest_addr[addrlen] = '\0';
1250         free(c->path);
1251         c->path = NULL;
1252         if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
1253                 if (addrlen >= NI_MAXHOST) {
1254                         error("channel %d: dynamic request: socks5 hostname "
1255                             "\"%.100s\" too long", c->self, dest_addr);
1256                         return -1;
1257                 }
1258                 c->path = xstrdup(dest_addr);
1259         } else {
1260                 if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
1261                         return -1;
1262                 c->path = xstrdup(ntop);
1263         }
1264         c->host_port = ntohs(dest_port);
1265
1266         debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
1267             c->self, c->path, c->host_port, s5_req.command);
1268
1269         s5_rsp.version = 0x05;
1270         s5_rsp.command = SSH_SOCKS5_SUCCESS;
1271         s5_rsp.reserved = 0;                    /* ignored */
1272         s5_rsp.atyp = SSH_SOCKS5_IPV4;
1273         dest_port = 0;                          /* ignored */
1274
1275         buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
1276         buffer_put_int(&c->output, ntohl(INADDR_ANY)); /* bind address */
1277         buffer_append(&c->output, &dest_port, sizeof(dest_port));
1278         return 1;
1279 }
1280
1281 Channel *
1282 channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
1283     int in, int out)
1284 {
1285         Channel *c;
1286
1287         debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
1288             port_to_connect);
1289
1290         c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
1291             -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
1292             0, "stdio-forward", /*nonblock*/0);
1293
1294         c->path = xstrdup(host_to_connect);
1295         c->host_port = port_to_connect;
1296         c->listening_port = 0;
1297         c->force_drain = 1;
1298
1299         channel_register_fds(c, in, out, -1, 0, 1, 0);
1300         port_open_helper(c, "direct-tcpip");
1301
1302         return c;
1303 }
1304
1305 /* dynamic port forwarding */
1306 static void
1307 channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
1308 {
1309         u_char *p;
1310         u_int have;
1311         int ret;
1312
1313         have = buffer_len(&c->input);
1314         debug2("channel %d: pre_dynamic: have %d", c->self, have);
1315         /* buffer_dump(&c->input); */
1316         /* check if the fixed size part of the packet is in buffer. */
1317         if (have < 3) {
1318                 /* need more */
1319                 FD_SET(c->sock, readset);
1320                 return;
1321         }
1322         /* try to guess the protocol */
1323         p = buffer_ptr(&c->input);
1324         switch (p[0]) {
1325         case 0x04:
1326                 ret = channel_decode_socks4(c, readset, writeset);
1327                 break;
1328         case 0x05:
1329                 ret = channel_decode_socks5(c, readset, writeset);
1330                 break;
1331         default:
1332                 ret = -1;
1333                 break;
1334         }
1335         if (ret < 0) {
1336                 chan_mark_dead(c);
1337         } else if (ret == 0) {
1338                 debug2("channel %d: pre_dynamic: need more", c->self);
1339                 /* need more */
1340                 FD_SET(c->sock, readset);
1341         } else {
1342                 /* switch to the next state */
1343                 c->type = SSH_CHANNEL_OPENING;
1344                 port_open_helper(c, "direct-tcpip");
1345         }
1346 }
1347
1348 /* This is our fake X11 server socket. */
1349 /* ARGSUSED */
1350 static void
1351 channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
1352 {
1353         Channel *nc;
1354         struct sockaddr_storage addr;
1355         int newsock, oerrno;
1356         socklen_t addrlen;
1357         char buf[16384], *remote_ipaddr;
1358         int remote_port;
1359
1360         if (FD_ISSET(c->sock, readset)) {
1361                 debug("X11 connection requested.");
1362                 addrlen = sizeof(addr);
1363                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1364                 if (c->single_connection) {
1365                         oerrno = errno;
1366                         debug2("single_connection: closing X11 listener.");
1367                         channel_close_fd(&c->sock);
1368                         chan_mark_dead(c);
1369                         errno = oerrno;
1370                 }
1371                 if (newsock < 0) {
1372                         if (errno != EINTR && errno != EWOULDBLOCK &&
1373                             errno != ECONNABORTED)
1374                                 error("accept: %.100s", strerror(errno));
1375                         if (errno == EMFILE || errno == ENFILE)
1376                                 c->notbefore = monotime() + 1;
1377                         return;
1378                 }
1379                 set_nodelay(newsock);
1380                 remote_ipaddr = get_peer_ipaddr(newsock);
1381                 remote_port = get_peer_port(newsock);
1382                 snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
1383                     remote_ipaddr, remote_port);
1384
1385                 nc = channel_new("accepted x11 socket",
1386                     SSH_CHANNEL_OPENING, newsock, newsock, -1,
1387                     c->local_window_max, c->local_maxpacket, 0, buf, 1);
1388                 if (compat20) {
1389                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1390                         packet_put_cstring("x11");
1391                         packet_put_int(nc->self);
1392                         packet_put_int(nc->local_window_max);
1393                         packet_put_int(nc->local_maxpacket);
1394                         /* originator ipaddr and port */
1395                         packet_put_cstring(remote_ipaddr);
1396                         if (datafellows & SSH_BUG_X11FWD) {
1397                                 debug2("ssh2 x11 bug compat mode");
1398                         } else {
1399                                 packet_put_int(remote_port);
1400                         }
1401                         packet_send();
1402                 } else {
1403                         packet_start(SSH_SMSG_X11_OPEN);
1404                         packet_put_int(nc->self);
1405                         if (packet_get_protocol_flags() &
1406                             SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1407                                 packet_put_cstring(buf);
1408                         packet_send();
1409                 }
1410                 free(remote_ipaddr);
1411         }
1412 }
1413
1414 static void
1415 port_open_helper(Channel *c, char *rtype)
1416 {
1417         char buf[1024];
1418         char *local_ipaddr = get_local_ipaddr(c->sock);
1419         int local_port = c->sock == -1 ? 65536 : get_sock_port(c->sock, 1);
1420         char *remote_ipaddr = get_peer_ipaddr(c->sock);
1421         int remote_port = get_peer_port(c->sock);
1422
1423         if (remote_port == -1) {
1424                 /* Fake addr/port to appease peers that validate it (Tectia) */
1425                 free(remote_ipaddr);
1426                 remote_ipaddr = xstrdup("127.0.0.1");
1427                 remote_port = 65535;
1428         }
1429
1430         snprintf(buf, sizeof buf,
1431             "%s: listening port %d for %.100s port %d, "
1432             "connect from %.200s port %d to %.100s port %d",
1433             rtype, c->listening_port, c->path, c->host_port,
1434             remote_ipaddr, remote_port, local_ipaddr, local_port);
1435
1436         free(c->remote_name);
1437         c->remote_name = xstrdup(buf);
1438
1439         if (compat20) {
1440                 packet_start(SSH2_MSG_CHANNEL_OPEN);
1441                 packet_put_cstring(rtype);
1442                 packet_put_int(c->self);
1443                 packet_put_int(c->local_window_max);
1444                 packet_put_int(c->local_maxpacket);
1445                 if (strcmp(rtype, "direct-tcpip") == 0) {
1446                         /* target host, port */
1447                         packet_put_cstring(c->path);
1448                         packet_put_int(c->host_port);
1449                 } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) {
1450                         /* target path */
1451                         packet_put_cstring(c->path);
1452                 } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1453                         /* listen path */
1454                         packet_put_cstring(c->path);
1455                 } else {
1456                         /* listen address, port */
1457                         packet_put_cstring(c->path);
1458                         packet_put_int(local_port);
1459                 }
1460                 if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) {
1461                         /* reserved for future owner/mode info */
1462                         packet_put_cstring("");
1463                 } else {
1464                         /* originator host and port */
1465                         packet_put_cstring(remote_ipaddr);
1466                         packet_put_int((u_int)remote_port);
1467                 }
1468                 packet_send();
1469         } else {
1470                 packet_start(SSH_MSG_PORT_OPEN);
1471                 packet_put_int(c->self);
1472                 packet_put_cstring(c->path);
1473                 packet_put_int(c->host_port);
1474                 if (packet_get_protocol_flags() &
1475                     SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
1476                         packet_put_cstring(c->remote_name);
1477                 packet_send();
1478         }
1479         free(remote_ipaddr);
1480         free(local_ipaddr);
1481 }
1482
1483 static void
1484 channel_set_reuseaddr(int fd)
1485 {
1486         int on = 1;
1487
1488         /*
1489          * Set socket options.
1490          * Allow local port reuse in TIME_WAIT.
1491          */
1492         if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
1493                 error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
1494 }
1495
1496 void
1497 channel_set_x11_refuse_time(u_int refuse_time)
1498 {
1499         x11_refuse_time = refuse_time;
1500 }
1501
1502 /*
1503  * This socket is listening for connections to a forwarded TCP/IP port.
1504  */
1505 /* ARGSUSED */
1506 static void
1507 channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
1508 {
1509         Channel *nc;
1510         struct sockaddr_storage addr;
1511         int newsock, nextstate;
1512         socklen_t addrlen;
1513         char *rtype;
1514
1515         if (FD_ISSET(c->sock, readset)) {
1516                 debug("Connection to port %d forwarding "
1517                     "to %.100s port %d requested.",
1518                     c->listening_port, c->path, c->host_port);
1519
1520                 if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
1521                         nextstate = SSH_CHANNEL_OPENING;
1522                         rtype = "forwarded-tcpip";
1523                 } else if (c->type == SSH_CHANNEL_RUNIX_LISTENER) {
1524                         nextstate = SSH_CHANNEL_OPENING;
1525                         rtype = "forwarded-streamlocal@openssh.com";
1526                 } else if (c->host_port == PORT_STREAMLOCAL) {
1527                         nextstate = SSH_CHANNEL_OPENING;
1528                         rtype = "direct-streamlocal@openssh.com";
1529                 } else if (c->host_port == 0) {
1530                         nextstate = SSH_CHANNEL_DYNAMIC;
1531                         rtype = "dynamic-tcpip";
1532                 } else {
1533                         nextstate = SSH_CHANNEL_OPENING;
1534                         rtype = "direct-tcpip";
1535                 }
1536
1537                 addrlen = sizeof(addr);
1538                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1539                 if (newsock < 0) {
1540                         if (errno != EINTR && errno != EWOULDBLOCK &&
1541                             errno != ECONNABORTED)
1542                                 error("accept: %.100s", strerror(errno));
1543                         if (errno == EMFILE || errno == ENFILE)
1544                                 c->notbefore = monotime() + 1;
1545                         return;
1546                 }
1547                 if (c->host_port != PORT_STREAMLOCAL)
1548                         set_nodelay(newsock);
1549                 nc = channel_new(rtype, nextstate, newsock, newsock, -1,
1550                     c->local_window_max, c->local_maxpacket, 0, rtype, 1);
1551                 nc->listening_port = c->listening_port;
1552                 nc->host_port = c->host_port;
1553                 if (c->path != NULL)
1554                         nc->path = xstrdup(c->path);
1555
1556                 if (nextstate != SSH_CHANNEL_DYNAMIC)
1557                         port_open_helper(nc, rtype);
1558         }
1559 }
1560
1561 /*
1562  * This is the authentication agent socket listening for connections from
1563  * clients.
1564  */
1565 /* ARGSUSED */
1566 static void
1567 channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
1568 {
1569         Channel *nc;
1570         int newsock;
1571         struct sockaddr_storage addr;
1572         socklen_t addrlen;
1573
1574         if (FD_ISSET(c->sock, readset)) {
1575                 addrlen = sizeof(addr);
1576                 newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen);
1577                 if (newsock < 0) {
1578                         error("accept from auth socket: %.100s",
1579                             strerror(errno));
1580                         if (errno == EMFILE || errno == ENFILE)
1581                                 c->notbefore = monotime() + 1;
1582                         return;
1583                 }
1584                 nc = channel_new("accepted auth socket",
1585                     SSH_CHANNEL_OPENING, newsock, newsock, -1,
1586                     c->local_window_max, c->local_maxpacket,
1587                     0, "accepted auth socket", 1);
1588                 if (compat20) {
1589                         packet_start(SSH2_MSG_CHANNEL_OPEN);
1590                         packet_put_cstring("auth-agent@openssh.com");
1591                         packet_put_int(nc->self);
1592                         packet_put_int(c->local_window_max);
1593                         packet_put_int(c->local_maxpacket);
1594                 } else {
1595                         packet_start(SSH_SMSG_AGENT_OPEN);
1596                         packet_put_int(nc->self);
1597                 }
1598                 packet_send();
1599         }
1600 }
1601
1602 /* ARGSUSED */
1603 static void
1604 channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
1605 {
1606         int err = 0, sock;
1607         socklen_t sz = sizeof(err);
1608
1609         if (FD_ISSET(c->sock, writeset)) {
1610                 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
1611                         err = errno;
1612                         error("getsockopt SO_ERROR failed");
1613                 }
1614                 if (err == 0) {
1615                         debug("channel %d: connected to %s port %d",
1616                             c->self, c->connect_ctx.host, c->connect_ctx.port);
1617                         channel_connect_ctx_free(&c->connect_ctx);
1618                         c->type = SSH_CHANNEL_OPEN;
1619                         if (compat20) {
1620                                 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
1621                                 packet_put_int(c->remote_id);
1622                                 packet_put_int(c->self);
1623                                 packet_put_int(c->local_window);
1624                                 packet_put_int(c->local_maxpacket);
1625                         } else {
1626                                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
1627                                 packet_put_int(c->remote_id);
1628                                 packet_put_int(c->self);
1629                         }
1630                 } else {
1631                         debug("channel %d: connection failed: %s",
1632                             c->self, strerror(err));
1633                         /* Try next address, if any */
1634                         if ((sock = connect_next(&c->connect_ctx)) > 0) {
1635                                 close(c->sock);
1636                                 c->sock = c->rfd = c->wfd = sock;
1637                                 channel_max_fd = channel_find_maxfd();
1638                                 return;
1639                         }
1640                         /* Exhausted all addresses */
1641                         error("connect_to %.100s port %d: failed.",
1642                             c->connect_ctx.host, c->connect_ctx.port);
1643                         channel_connect_ctx_free(&c->connect_ctx);
1644                         if (compat20) {
1645                                 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
1646                                 packet_put_int(c->remote_id);
1647                                 packet_put_int(SSH2_OPEN_CONNECT_FAILED);
1648                                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
1649                                         packet_put_cstring(strerror(err));
1650                                         packet_put_cstring("");
1651                                 }
1652                         } else {
1653                                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
1654                                 packet_put_int(c->remote_id);
1655                         }
1656                         chan_mark_dead(c);
1657                 }
1658                 packet_send();
1659         }
1660 }
1661
1662 /* ARGSUSED */
1663 static int
1664 channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
1665 {
1666         char buf[CHAN_RBUF];
1667         int len, force;
1668
1669         force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED;
1670         if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) {
1671                 errno = 0;
1672                 len = read(c->rfd, buf, sizeof(buf));
1673                 if (len < 0 && (errno == EINTR ||
1674                     ((errno == EAGAIN || errno == EWOULDBLOCK) && !force)))
1675                         return 1;
1676 #ifndef PTY_ZEROREAD
1677                 if (len <= 0) {
1678 #else
1679                 if ((!c->isatty && len <= 0) ||
1680                     (c->isatty && (len < 0 || (len == 0 && errno != 0)))) {
1681 #endif
1682                         debug2("channel %d: read<=0 rfd %d len %d",
1683                             c->self, c->rfd, len);
1684                         if (c->type != SSH_CHANNEL_OPEN) {
1685                                 debug2("channel %d: not open", c->self);
1686                                 chan_mark_dead(c);
1687                                 return -1;
1688                         } else if (compat13) {
1689                                 buffer_clear(&c->output);
1690                                 c->type = SSH_CHANNEL_INPUT_DRAINING;
1691                                 debug2("channel %d: input draining.", c->self);
1692                         } else {
1693                                 chan_read_failed(c);
1694                         }
1695                         return -1;
1696                 }
1697                 if (c->input_filter != NULL) {
1698                         if (c->input_filter(c, buf, len) == -1) {
1699                                 debug2("channel %d: filter stops", c->self);
1700                                 chan_read_failed(c);
1701                         }
1702                 } else if (c->datagram) {
1703                         buffer_put_string(&c->input, buf, len);
1704                 } else {
1705                         buffer_append(&c->input, buf, len);
1706                 }
1707         }
1708         return 1;
1709 }
1710
1711 /* ARGSUSED */
1712 static int
1713 channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
1714 {
1715         struct termios tio;
1716         u_char *data = NULL, *buf;
1717         u_int dlen, olen = 0;
1718         int len;
1719
1720         /* Send buffered output data to the socket. */
1721         if (c->wfd != -1 &&
1722             FD_ISSET(c->wfd, writeset) &&
1723             buffer_len(&c->output) > 0) {
1724                 olen = buffer_len(&c->output);
1725                 if (c->output_filter != NULL) {
1726                         if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
1727                                 debug2("channel %d: filter stops", c->self);
1728                                 if (c->type != SSH_CHANNEL_OPEN)
1729                                         chan_mark_dead(c);
1730                                 else
1731                                         chan_write_failed(c);
1732                                 return -1;
1733                         }
1734                 } else if (c->datagram) {
1735                         buf = data = buffer_get_string(&c->output, &dlen);
1736                 } else {
1737                         buf = data = buffer_ptr(&c->output);
1738                         dlen = buffer_len(&c->output);
1739                 }
1740
1741                 if (c->datagram) {
1742                         /* ignore truncated writes, datagrams might get lost */
1743                         len = write(c->wfd, buf, dlen);
1744                         free(data);
1745                         if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1746                             errno == EWOULDBLOCK))
1747                                 return 1;
1748                         if (len <= 0) {
1749                                 if (c->type != SSH_CHANNEL_OPEN)
1750                                         chan_mark_dead(c);
1751                                 else
1752                                         chan_write_failed(c);
1753                                 return -1;
1754                         }
1755                         goto out;
1756                 }
1757 #ifdef _AIX
1758                 /* XXX: Later AIX versions can't push as much data to tty */
1759                 if (compat20 && c->wfd_isatty)
1760                         dlen = MIN(dlen, 8*1024);
1761 #endif
1762
1763                 len = write(c->wfd, buf, dlen);
1764                 if (len < 0 &&
1765                     (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK))
1766                         return 1;
1767                 if (len <= 0) {
1768                         if (c->type != SSH_CHANNEL_OPEN) {
1769                                 debug2("channel %d: not open", c->self);
1770                                 chan_mark_dead(c);
1771                                 return -1;
1772                         } else if (compat13) {
1773                                 buffer_clear(&c->output);
1774                                 debug2("channel %d: input draining.", c->self);
1775                                 c->type = SSH_CHANNEL_INPUT_DRAINING;
1776                         } else {
1777                                 chan_write_failed(c);
1778                         }
1779                         return -1;
1780                 }
1781 #ifndef BROKEN_TCGETATTR_ICANON
1782                 if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') {
1783                         if (tcgetattr(c->wfd, &tio) == 0 &&
1784                             !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
1785                                 /*
1786                                  * Simulate echo to reduce the impact of
1787                                  * traffic analysis. We need to match the
1788                                  * size of a SSH2_MSG_CHANNEL_DATA message
1789                                  * (4 byte channel id + buf)
1790                                  */
1791                                 packet_send_ignore(4 + len);
1792                                 packet_send();
1793                         }
1794                 }
1795 #endif
1796                 buffer_consume(&c->output, len);
1797         }
1798  out:
1799         if (compat20 && olen > 0)
1800                 c->local_consumed += olen - buffer_len(&c->output);
1801         return 1;
1802 }
1803
1804 static int
1805 channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset)
1806 {
1807         char buf[CHAN_RBUF];
1808         int len;
1809
1810 /** XXX handle drain efd, too */
1811         if (c->efd != -1) {
1812                 if (c->extended_usage == CHAN_EXTENDED_WRITE &&
1813                     FD_ISSET(c->efd, writeset) &&
1814                     buffer_len(&c->extended) > 0) {
1815                         len = write(c->efd, buffer_ptr(&c->extended),
1816                             buffer_len(&c->extended));
1817                         debug2("channel %d: written %d to efd %d",
1818                             c->self, len, c->efd);
1819                         if (len < 0 && (errno == EINTR || errno == EAGAIN ||
1820                             errno == EWOULDBLOCK))
1821                                 return 1;
1822                         if (len <= 0) {
1823                                 debug2("channel %d: closing write-efd %d",
1824                                     c->self, c->efd);
1825                                 channel_close_fd(&c->efd);
1826                         } else {
1827                                 buffer_consume(&c->extended, len);
1828                                 c->local_consumed += len;
1829                         }
1830                 } else if (c->efd != -1 &&
1831                     (c->extended_usage == CHAN_EXTENDED_READ ||
1832                     c->extended_usage == CHAN_EXTENDED_IGNORE) &&
1833                     (c->detach_close || FD_ISSET(c->efd, readset))) {
1834                         len = read(c->efd, buf, sizeof(buf));
1835                         debug2("channel %d: read %d from efd %d",
1836                             c->self, len, c->efd);
1837                         if (len < 0 && (errno == EINTR || ((errno == EAGAIN ||
1838                             errno == EWOULDBLOCK) && !c->detach_close)))
1839                                 return 1;
1840                         if (len <= 0) {
1841                                 debug2("channel %d: closing read-efd %d",
1842                                     c->self, c->efd);
1843                                 channel_close_fd(&c->efd);
1844                         } else {
1845                                 if (c->extended_usage == CHAN_EXTENDED_IGNORE) {
1846                                         debug3("channel %d: discard efd",
1847                                             c->self);
1848                                 } else
1849                                         buffer_append(&c->extended, buf, len);
1850                         }
1851                 }
1852         }
1853         return 1;
1854 }
1855
1856 static int
1857 channel_check_window(Channel *c)
1858 {
1859         if (c->type == SSH_CHANNEL_OPEN &&
1860             !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
1861             ((c->local_window_max - c->local_window >
1862             c->local_maxpacket*3) ||
1863             c->local_window < c->local_window_max/2) &&
1864             c->local_consumed > 0) {
1865                 packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
1866                 packet_put_int(c->remote_id);
1867                 packet_put_int(c->local_consumed);
1868                 packet_send();
1869                 debug2("channel %d: window %d sent adjust %d",
1870                     c->self, c->local_window,
1871                     c->local_consumed);
1872                 c->local_window += c->local_consumed;
1873                 c->local_consumed = 0;
1874         }
1875         return 1;
1876 }
1877
1878 static void
1879 channel_post_open(Channel *c, fd_set *readset, fd_set *writeset)
1880 {
1881         channel_handle_rfd(c, readset, writeset);
1882         channel_handle_wfd(c, readset, writeset);
1883         if (!compat20)
1884                 return;
1885         channel_handle_efd(c, readset, writeset);
1886         channel_check_window(c);
1887 }
1888
1889 static u_int
1890 read_mux(Channel *c, u_int need)
1891 {
1892         char buf[CHAN_RBUF];
1893         int len;
1894         u_int rlen;
1895
1896         if (buffer_len(&c->input) < need) {
1897                 rlen = need - buffer_len(&c->input);
1898                 len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF));
1899                 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1900                         return buffer_len(&c->input);
1901                 if (len <= 0) {
1902                         debug2("channel %d: ctl read<=0 rfd %d len %d",
1903                             c->self, c->rfd, len);
1904                         chan_read_failed(c);
1905                         return 0;
1906                 } else
1907                         buffer_append(&c->input, buf, len);
1908         }
1909         return buffer_len(&c->input);
1910 }
1911
1912 static void
1913 channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
1914 {
1915         u_int need;
1916         ssize_t len;
1917
1918         if (!compat20)
1919                 fatal("%s: entered with !compat20", __func__);
1920
1921         if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
1922             (c->istate == CHAN_INPUT_OPEN ||
1923             c->istate == CHAN_INPUT_WAIT_DRAIN)) {
1924                 /*
1925                  * Don't not read past the precise end of packets to
1926                  * avoid disrupting fd passing.
1927                  */
1928                 if (read_mux(c, 4) < 4) /* read header */
1929                         return;
1930                 need = get_u32(buffer_ptr(&c->input));
1931 #define CHANNEL_MUX_MAX_PACKET  (256 * 1024)
1932                 if (need > CHANNEL_MUX_MAX_PACKET) {
1933                         debug2("channel %d: packet too big %u > %u",
1934                             c->self, CHANNEL_MUX_MAX_PACKET, need);
1935                         chan_rcvd_oclose(c);
1936                         return;
1937                 }
1938                 if (read_mux(c, need + 4) < need + 4) /* read body */
1939                         return;
1940                 if (c->mux_rcb(c) != 0) {
1941                         debug("channel %d: mux_rcb failed", c->self);
1942                         chan_mark_dead(c);
1943                         return;
1944                 }
1945         }
1946
1947         if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) &&
1948             buffer_len(&c->output) > 0) {
1949                 len = write(c->wfd, buffer_ptr(&c->output),
1950                     buffer_len(&c->output));
1951                 if (len < 0 && (errno == EINTR || errno == EAGAIN))
1952                         return;
1953                 if (len <= 0) {
1954                         chan_mark_dead(c);
1955                         return;
1956                 }
1957                 buffer_consume(&c->output, len);
1958         }
1959 }
1960
1961 static void
1962 channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset)
1963 {
1964         Channel *nc;
1965         struct sockaddr_storage addr;
1966         socklen_t addrlen;
1967         int newsock;
1968         uid_t euid;
1969         gid_t egid;
1970
1971         if (!FD_ISSET(c->sock, readset))
1972                 return;
1973
1974         debug("multiplexing control connection");
1975
1976         /*
1977          * Accept connection on control socket
1978          */
1979         memset(&addr, 0, sizeof(addr));
1980         addrlen = sizeof(addr);
1981         if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
1982             &addrlen)) == -1) {
1983                 error("%s accept: %s", __func__, strerror(errno));
1984                 if (errno == EMFILE || errno == ENFILE)
1985                         c->notbefore = monotime() + 1;
1986                 return;
1987         }
1988
1989         if (getpeereid(newsock, &euid, &egid) < 0) {
1990                 error("%s getpeereid failed: %s", __func__,
1991                     strerror(errno));
1992                 close(newsock);
1993                 return;
1994         }
1995         if ((euid != 0) && (getuid() != euid)) {
1996                 error("multiplex uid mismatch: peer euid %u != uid %u",
1997                     (u_int)euid, (u_int)getuid());
1998                 close(newsock);
1999                 return;
2000         }
2001         nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT,
2002             newsock, newsock, -1, c->local_window_max,
2003             c->local_maxpacket, 0, "mux-control", 1);
2004         nc->mux_rcb = c->mux_rcb;
2005         debug3("%s: new mux channel %d fd %d", __func__,
2006             nc->self, nc->sock);
2007         /* establish state */
2008         nc->mux_rcb(nc);
2009         /* mux state transitions must not elicit protocol messages */
2010         nc->flags |= CHAN_LOCAL;
2011 }
2012
2013 /* ARGSUSED */
2014 static void
2015 channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset)
2016 {
2017         int len;
2018
2019         /* Send buffered output data to the socket. */
2020         if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
2021                 len = write(c->sock, buffer_ptr(&c->output),
2022                             buffer_len(&c->output));
2023                 if (len <= 0)
2024                         buffer_clear(&c->output);
2025                 else
2026                         buffer_consume(&c->output, len);
2027         }
2028 }
2029
2030 static void
2031 channel_handler_init_20(void)
2032 {
2033         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open;
2034         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open;
2035         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
2036         channel_pre[SSH_CHANNEL_RPORT_LISTENER] =       &channel_pre_listener;
2037         channel_pre[SSH_CHANNEL_UNIX_LISTENER] =        &channel_pre_listener;
2038         channel_pre[SSH_CHANNEL_RUNIX_LISTENER] =       &channel_pre_listener;
2039         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
2040         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
2041         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
2042         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
2043         channel_pre[SSH_CHANNEL_MUX_LISTENER] =         &channel_pre_listener;
2044         channel_pre[SSH_CHANNEL_MUX_CLIENT] =           &channel_pre_mux_client;
2045
2046         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
2047         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
2048         channel_post[SSH_CHANNEL_RPORT_LISTENER] =      &channel_post_port_listener;
2049         channel_post[SSH_CHANNEL_UNIX_LISTENER] =       &channel_post_port_listener;
2050         channel_post[SSH_CHANNEL_RUNIX_LISTENER] =      &channel_post_port_listener;
2051         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
2052         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
2053         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
2054         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
2055         channel_post[SSH_CHANNEL_MUX_LISTENER] =        &channel_post_mux_listener;
2056         channel_post[SSH_CHANNEL_MUX_CLIENT] =          &channel_post_mux_client;
2057 }
2058
2059 static void
2060 channel_handler_init_13(void)
2061 {
2062         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open_13;
2063         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open_13;
2064         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
2065         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
2066         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
2067         channel_pre[SSH_CHANNEL_INPUT_DRAINING] =       &channel_pre_input_draining;
2068         channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] =      &channel_pre_output_draining;
2069         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
2070         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
2071
2072         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
2073         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
2074         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
2075         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
2076         channel_post[SSH_CHANNEL_OUTPUT_DRAINING] =     &channel_post_output_drain_13;
2077         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
2078         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
2079 }
2080
2081 static void
2082 channel_handler_init_15(void)
2083 {
2084         channel_pre[SSH_CHANNEL_OPEN] =                 &channel_pre_open;
2085         channel_pre[SSH_CHANNEL_X11_OPEN] =             &channel_pre_x11_open;
2086         channel_pre[SSH_CHANNEL_X11_LISTENER] =         &channel_pre_listener;
2087         channel_pre[SSH_CHANNEL_PORT_LISTENER] =        &channel_pre_listener;
2088         channel_pre[SSH_CHANNEL_AUTH_SOCKET] =          &channel_pre_listener;
2089         channel_pre[SSH_CHANNEL_CONNECTING] =           &channel_pre_connecting;
2090         channel_pre[SSH_CHANNEL_DYNAMIC] =              &channel_pre_dynamic;
2091
2092         channel_post[SSH_CHANNEL_X11_LISTENER] =        &channel_post_x11_listener;
2093         channel_post[SSH_CHANNEL_PORT_LISTENER] =       &channel_post_port_listener;
2094         channel_post[SSH_CHANNEL_AUTH_SOCKET] =         &channel_post_auth_listener;
2095         channel_post[SSH_CHANNEL_OPEN] =                &channel_post_open;
2096         channel_post[SSH_CHANNEL_CONNECTING] =          &channel_post_connecting;
2097         channel_post[SSH_CHANNEL_DYNAMIC] =             &channel_post_open;
2098 }
2099
2100 static void
2101 channel_handler_init(void)
2102 {
2103         int i;
2104
2105         for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
2106                 channel_pre[i] = NULL;
2107                 channel_post[i] = NULL;
2108         }
2109         if (compat20)
2110                 channel_handler_init_20();
2111         else if (compat13)
2112                 channel_handler_init_13();
2113         else
2114                 channel_handler_init_15();
2115 }
2116
2117 /* gc dead channels */
2118 static void
2119 channel_garbage_collect(Channel *c)
2120 {
2121         if (c == NULL)
2122                 return;
2123         if (c->detach_user != NULL) {
2124                 if (!chan_is_dead(c, c->detach_close))
2125                         return;
2126                 debug2("channel %d: gc: notify user", c->self);
2127                 c->detach_user(c->self, NULL);
2128                 /* if we still have a callback */
2129                 if (c->detach_user != NULL)
2130                         return;
2131                 debug2("channel %d: gc: user detached", c->self);
2132         }
2133         if (!chan_is_dead(c, 1))
2134                 return;
2135         debug2("channel %d: garbage collecting", c->self);
2136         channel_free(c);
2137 }
2138
2139 static void
2140 channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset,
2141     time_t *unpause_secs)
2142 {
2143         static int did_init = 0;
2144         u_int i, oalloc;
2145         Channel *c;
2146         time_t now;
2147
2148         if (!did_init) {
2149                 channel_handler_init();
2150                 did_init = 1;
2151         }
2152         now = monotime();
2153         if (unpause_secs != NULL)
2154                 *unpause_secs = 0;
2155         for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
2156                 c = channels[i];
2157                 if (c == NULL)
2158                         continue;
2159                 if (c->delayed) {
2160                         if (ftab == channel_pre)
2161                                 c->delayed = 0;
2162                         else
2163                                 continue;
2164                 }
2165                 if (ftab[c->type] != NULL) {
2166                         /*
2167                          * Run handlers that are not paused.
2168                          */
2169                         if (c->notbefore <= now)
2170                                 (*ftab[c->type])(c, readset, writeset);
2171                         else if (unpause_secs != NULL) {
2172                                 /*
2173                                  * Collect the time that the earliest
2174                                  * channel comes off pause.
2175                                  */
2176                                 debug3("%s: chan %d: skip for %d more seconds",
2177                                     __func__, c->self,
2178                                     (int)(c->notbefore - now));
2179                                 if (*unpause_secs == 0 ||
2180                                     (c->notbefore - now) < *unpause_secs)
2181                                         *unpause_secs = c->notbefore - now;
2182                         }
2183                 }
2184                 channel_garbage_collect(c);
2185         }
2186         if (unpause_secs != NULL && *unpause_secs != 0)
2187                 debug3("%s: first channel unpauses in %d seconds",
2188                     __func__, (int)*unpause_secs);
2189 }
2190
2191 /*
2192  * Allocate/update select bitmasks and add any bits relevant to channels in
2193  * select bitmasks.
2194  */
2195 void
2196 channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
2197     u_int *nallocp, time_t *minwait_secs, int rekeying)
2198 {
2199         u_int n, sz, nfdset;
2200
2201         n = MAX(*maxfdp, channel_max_fd);
2202
2203         nfdset = howmany(n+1, NFDBITS);
2204         /* Explicitly test here, because xrealloc isn't always called */
2205         if (nfdset && SIZE_MAX / nfdset < sizeof(fd_mask))
2206                 fatal("channel_prepare_select: max_fd (%d) is too large", n);
2207         sz = nfdset * sizeof(fd_mask);
2208
2209         /* perhaps check sz < nalloc/2 and shrink? */
2210         if (*readsetp == NULL || sz > *nallocp) {
2211                 *readsetp = xreallocarray(*readsetp, nfdset, sizeof(fd_mask));
2212                 *writesetp = xreallocarray(*writesetp, nfdset, sizeof(fd_mask));
2213                 *nallocp = sz;
2214         }
2215         *maxfdp = n;
2216         memset(*readsetp, 0, sz);
2217         memset(*writesetp, 0, sz);
2218
2219         if (!rekeying)
2220                 channel_handler(channel_pre, *readsetp, *writesetp,
2221                     minwait_secs);
2222 }
2223
2224 /*
2225  * After select, perform any appropriate operations for channels which have
2226  * events pending.
2227  */
2228 void
2229 channel_after_select(fd_set *readset, fd_set *writeset)
2230 {
2231         channel_handler(channel_post, readset, writeset, NULL);
2232 }
2233
2234
2235 /* If there is data to send to the connection, enqueue some of it now. */
2236 void
2237 channel_output_poll(void)
2238 {
2239         Channel *c;
2240         u_int i, len;
2241
2242         for (i = 0; i < channels_alloc; i++) {
2243                 c = channels[i];
2244                 if (c == NULL)
2245                         continue;
2246
2247                 /*
2248                  * We are only interested in channels that can have buffered
2249                  * incoming data.
2250                  */
2251                 if (compat13) {
2252                         if (c->type != SSH_CHANNEL_OPEN &&
2253                             c->type != SSH_CHANNEL_INPUT_DRAINING)
2254                                 continue;
2255                 } else {
2256                         if (c->type != SSH_CHANNEL_OPEN)
2257                                 continue;
2258                 }
2259                 if (compat20 &&
2260                     (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
2261                         /* XXX is this true? */
2262                         debug3("channel %d: will not send data after close", c->self);
2263                         continue;
2264                 }
2265
2266                 /* Get the amount of buffered data for this channel. */
2267                 if ((c->istate == CHAN_INPUT_OPEN ||
2268                     c->istate == CHAN_INPUT_WAIT_DRAIN) &&
2269                     (len = buffer_len(&c->input)) > 0) {
2270                         if (c->datagram) {
2271                                 if (len > 0) {
2272                                         u_char *data;
2273                                         u_int dlen;
2274
2275                                         data = buffer_get_string(&c->input,
2276                                             &dlen);
2277                                         if (dlen > c->remote_window ||
2278                                             dlen > c->remote_maxpacket) {
2279                                                 debug("channel %d: datagram "
2280                                                     "too big for channel",
2281                                                     c->self);
2282                                                 free(data);
2283                                                 continue;
2284                                         }
2285                                         packet_start(SSH2_MSG_CHANNEL_DATA);
2286                                         packet_put_int(c->remote_id);
2287                                         packet_put_string(data, dlen);
2288                                         packet_send();
2289                                         c->remote_window -= dlen;
2290                                         free(data);
2291                                 }
2292                                 continue;
2293                         }
2294                         /*
2295                          * Send some data for the other side over the secure
2296                          * connection.
2297                          */
2298                         if (compat20) {
2299                                 if (len > c->remote_window)
2300                                         len = c->remote_window;
2301                                 if (len > c->remote_maxpacket)
2302                                         len = c->remote_maxpacket;
2303                         } else {
2304                                 if (packet_is_interactive()) {
2305                                         if (len > 1024)
2306                                                 len = 512;
2307                                 } else {
2308                                         /* Keep the packets at reasonable size. */
2309                                         if (len > packet_get_maxsize()/2)
2310                                                 len = packet_get_maxsize()/2;
2311                                 }
2312                         }
2313                         if (len > 0) {
2314                                 packet_start(compat20 ?
2315                                     SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
2316                                 packet_put_int(c->remote_id);
2317                                 packet_put_string(buffer_ptr(&c->input), len);
2318                                 packet_send();
2319                                 buffer_consume(&c->input, len);
2320                                 c->remote_window -= len;
2321                         }
2322                 } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
2323                         if (compat13)
2324                                 fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
2325                         /*
2326                          * input-buffer is empty and read-socket shutdown:
2327                          * tell peer, that we will not send more data: send IEOF.
2328                          * hack for extended data: delay EOF if EFD still in use.
2329                          */
2330                         if (CHANNEL_EFD_INPUT_ACTIVE(c))
2331                                 debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
2332                                     c->self, c->efd, buffer_len(&c->extended));
2333                         else
2334                                 chan_ibuf_empty(c);
2335                 }
2336                 /* Send extended data, i.e. stderr */
2337                 if (compat20 &&
2338                     !(c->flags & CHAN_EOF_SENT) &&
2339                     c->remote_window > 0 &&
2340                     (len = buffer_len(&c->extended)) > 0 &&
2341                     c->extended_usage == CHAN_EXTENDED_READ) {
2342                         debug2("channel %d: rwin %u elen %u euse %d",
2343                             c->self, c->remote_window, buffer_len(&c->extended),
2344                             c->extended_usage);
2345                         if (len > c->remote_window)
2346                                 len = c->remote_window;
2347                         if (len > c->remote_maxpacket)
2348                                 len = c->remote_maxpacket;
2349                         packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
2350                         packet_put_int(c->remote_id);
2351                         packet_put_int(SSH2_EXTENDED_DATA_STDERR);
2352                         packet_put_string(buffer_ptr(&c->extended), len);
2353                         packet_send();
2354                         buffer_consume(&c->extended, len);
2355                         c->remote_window -= len;
2356                         debug2("channel %d: sent ext data %d", c->self, len);
2357                 }
2358         }
2359 }
2360
2361
2362 /* -- protocol input */
2363
2364 /* ARGSUSED */
2365 int
2366 channel_input_data(int type, u_int32_t seq, void *ctxt)
2367 {
2368         int id;
2369         const u_char *data;
2370         u_int data_len, win_len;
2371         Channel *c;
2372
2373         /* Get the channel number and verify it. */
2374         id = packet_get_int();
2375         c = channel_lookup(id);
2376         if (c == NULL)
2377                 packet_disconnect("Received data for nonexistent channel %d.", id);
2378
2379         /* Ignore any data for non-open channels (might happen on close) */
2380         if (c->type != SSH_CHANNEL_OPEN &&
2381             c->type != SSH_CHANNEL_X11_OPEN)
2382                 return 0;
2383
2384         /* Get the data. */
2385         data = packet_get_string_ptr(&data_len);
2386         win_len = data_len;
2387         if (c->datagram)
2388                 win_len += 4;  /* string length header */
2389
2390         /*
2391          * Ignore data for protocol > 1.3 if output end is no longer open.
2392          * For protocol 2 the sending side is reducing its window as it sends
2393          * data, so we must 'fake' consumption of the data in order to ensure
2394          * that window updates are sent back.  Otherwise the connection might
2395          * deadlock.
2396          */
2397         if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
2398                 if (compat20) {
2399                         c->local_window -= win_len;
2400                         c->local_consumed += win_len;
2401                 }
2402                 return 0;
2403         }
2404
2405         if (compat20) {
2406                 if (win_len > c->local_maxpacket) {
2407                         logit("channel %d: rcvd big packet %d, maxpack %d",
2408                             c->self, win_len, c->local_maxpacket);
2409                 }
2410                 if (win_len > c->local_window) {
2411                         logit("channel %d: rcvd too much data %d, win %d",
2412                             c->self, win_len, c->local_window);
2413                         return 0;
2414                 }
2415                 c->local_window -= win_len;
2416         }
2417         if (c->datagram)
2418                 buffer_put_string(&c->output, data, data_len);
2419         else
2420                 buffer_append(&c->output, data, data_len);
2421         packet_check_eom();
2422         return 0;
2423 }
2424
2425 /* ARGSUSED */
2426 int
2427 channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
2428 {
2429         int id;
2430         char *data;
2431         u_int data_len, tcode;
2432         Channel *c;
2433
2434         /* Get the channel number and verify it. */
2435         id = packet_get_int();
2436         c = channel_lookup(id);
2437
2438         if (c == NULL)
2439                 packet_disconnect("Received extended_data for bad channel %d.", id);
2440         if (c->type != SSH_CHANNEL_OPEN) {
2441                 logit("channel %d: ext data for non open", id);
2442                 return 0;
2443         }
2444         if (c->flags & CHAN_EOF_RCVD) {
2445                 if (datafellows & SSH_BUG_EXTEOF)
2446                         debug("channel %d: accepting ext data after eof", id);
2447                 else
2448                         packet_disconnect("Received extended_data after EOF "
2449                             "on channel %d.", id);
2450         }
2451         tcode = packet_get_int();
2452         if (c->efd == -1 ||
2453             c->extended_usage != CHAN_EXTENDED_WRITE ||
2454             tcode != SSH2_EXTENDED_DATA_STDERR) {
2455                 logit("channel %d: bad ext data", c->self);
2456                 return 0;
2457         }
2458         data = packet_get_string(&data_len);
2459         packet_check_eom();
2460         if (data_len > c->local_window) {
2461                 logit("channel %d: rcvd too much extended_data %d, win %d",
2462                     c->self, data_len, c->local_window);
2463                 free(data);
2464                 return 0;
2465         }
2466         debug2("channel %d: rcvd ext data %d", c->self, data_len);
2467         c->local_window -= data_len;
2468         buffer_append(&c->extended, data, data_len);
2469         free(data);
2470         return 0;
2471 }
2472
2473 /* ARGSUSED */
2474 int
2475 channel_input_ieof(int type, u_int32_t seq, void *ctxt)
2476 {
2477         int id;
2478         Channel *c;
2479
2480         id = packet_get_int();
2481         packet_check_eom();
2482         c = channel_lookup(id);
2483         if (c == NULL)
2484                 packet_disconnect("Received ieof for nonexistent channel %d.", id);
2485         chan_rcvd_ieof(c);
2486
2487         /* XXX force input close */
2488         if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
2489                 debug("channel %d: FORCE input drain", c->self);
2490                 c->istate = CHAN_INPUT_WAIT_DRAIN;
2491                 if (buffer_len(&c->input) == 0)
2492                         chan_ibuf_empty(c);
2493         }
2494         return 0;
2495 }
2496
2497 /* ARGSUSED */
2498 int
2499 channel_input_close(int type, u_int32_t seq, void *ctxt)
2500 {
2501         int id;
2502         Channel *c;
2503
2504         id = packet_get_int();
2505         packet_check_eom();
2506         c = channel_lookup(id);
2507         if (c == NULL)
2508                 packet_disconnect("Received close for nonexistent channel %d.", id);
2509
2510         /*
2511          * Send a confirmation that we have closed the channel and no more
2512          * data is coming for it.
2513          */
2514         packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
2515         packet_put_int(c->remote_id);
2516         packet_send();
2517
2518         /*
2519          * If the channel is in closed state, we have sent a close request,
2520          * and the other side will eventually respond with a confirmation.
2521          * Thus, we cannot free the channel here, because then there would be
2522          * no-one to receive the confirmation.  The channel gets freed when
2523          * the confirmation arrives.
2524          */
2525         if (c->type != SSH_CHANNEL_CLOSED) {
2526                 /*
2527                  * Not a closed channel - mark it as draining, which will
2528                  * cause it to be freed later.
2529                  */
2530                 buffer_clear(&c->input);
2531                 c->type = SSH_CHANNEL_OUTPUT_DRAINING;
2532         }
2533         return 0;
2534 }
2535
2536 /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
2537 /* ARGSUSED */
2538 int
2539 channel_input_oclose(int type, u_int32_t seq, void *ctxt)
2540 {
2541         int id = packet_get_int();
2542         Channel *c = channel_lookup(id);
2543
2544         packet_check_eom();
2545         if (c == NULL)
2546                 packet_disconnect("Received oclose for nonexistent channel %d.", id);
2547         chan_rcvd_oclose(c);
2548         return 0;
2549 }
2550
2551 /* ARGSUSED */
2552 int
2553 channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
2554 {
2555         int id = packet_get_int();
2556         Channel *c = channel_lookup(id);
2557
2558         packet_check_eom();
2559         if (c == NULL)
2560                 packet_disconnect("Received close confirmation for "
2561                     "out-of-range channel %d.", id);
2562         if (c->type != SSH_CHANNEL_CLOSED && c->type != SSH_CHANNEL_ABANDONED)
2563                 packet_disconnect("Received close confirmation for "
2564                     "non-closed channel %d (type %d).", id, c->type);
2565         channel_free(c);
2566         return 0;
2567 }
2568
2569 /* ARGSUSED */
2570 int
2571 channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
2572 {
2573         int id, remote_id;
2574         Channel *c;
2575
2576         id = packet_get_int();
2577         c = channel_lookup(id);
2578
2579         if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2580                 packet_disconnect("Received open confirmation for "
2581                     "non-opening channel %d.", id);
2582         remote_id = packet_get_int();
2583         /* Record the remote channel number and mark that the channel is now open. */
2584         c->remote_id = remote_id;
2585         c->type = SSH_CHANNEL_OPEN;
2586
2587         if (compat20) {
2588                 c->remote_window = packet_get_int();
2589                 c->remote_maxpacket = packet_get_int();
2590                 if (c->open_confirm) {
2591                         debug2("callback start");
2592                         c->open_confirm(c->self, 1, c->open_confirm_ctx);
2593                         debug2("callback done");
2594                 }
2595                 debug2("channel %d: open confirm rwindow %u rmax %u", c->self,
2596                     c->remote_window, c->remote_maxpacket);
2597         }
2598         packet_check_eom();
2599         return 0;
2600 }
2601
2602 static char *
2603 reason2txt(int reason)
2604 {
2605         switch (reason) {
2606         case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
2607                 return "administratively prohibited";
2608         case SSH2_OPEN_CONNECT_FAILED:
2609                 return "connect failed";
2610         case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
2611                 return "unknown channel type";
2612         case SSH2_OPEN_RESOURCE_SHORTAGE:
2613                 return "resource shortage";
2614         }
2615         return "unknown reason";
2616 }
2617
2618 /* ARGSUSED */
2619 int
2620 channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
2621 {
2622         int id, reason;
2623         char *msg = NULL, *lang = NULL;
2624         Channel *c;
2625
2626         id = packet_get_int();
2627         c = channel_lookup(id);
2628
2629         if (c==NULL || c->type != SSH_CHANNEL_OPENING)
2630                 packet_disconnect("Received open failure for "
2631                     "non-opening channel %d.", id);
2632         if (compat20) {
2633                 reason = packet_get_int();
2634                 if (!(datafellows & SSH_BUG_OPENFAILURE)) {
2635                         msg  = packet_get_string(NULL);
2636                         lang = packet_get_string(NULL);
2637                 }
2638                 logit("channel %d: open failed: %s%s%s", id,
2639                     reason2txt(reason), msg ? ": ": "", msg ? msg : "");
2640                 free(msg);
2641                 free(lang);
2642                 if (c->open_confirm) {
2643                         debug2("callback start");
2644                         c->open_confirm(c->self, 0, c->open_confirm_ctx);
2645                         debug2("callback done");
2646                 }
2647         }
2648         packet_check_eom();
2649         /* Schedule the channel for cleanup/deletion. */
2650         chan_mark_dead(c);
2651         return 0;
2652 }
2653
2654 /* ARGSUSED */
2655 int
2656 channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
2657 {
2658         Channel *c;
2659         int id;
2660         u_int adjust, tmp;
2661
2662         if (!compat20)
2663                 return 0;
2664
2665         /* Get the channel number and verify it. */
2666         id = packet_get_int();
2667         c = channel_lookup(id);
2668
2669         if (c == NULL) {
2670                 logit("Received window adjust for non-open channel %d.", id);
2671                 return 0;
2672         }
2673         adjust = packet_get_int();
2674         packet_check_eom();
2675         debug2("channel %d: rcvd adjust %u", id, adjust);
2676         if ((tmp = c->remote_window + adjust) < c->remote_window)
2677                 fatal("channel %d: adjust %u overflows remote window %u",
2678                     id, adjust, c->remote_window);
2679         c->remote_window = tmp;
2680         return 0;
2681 }
2682
2683 /* ARGSUSED */
2684 int
2685 channel_input_port_open(int type, u_int32_t seq, void *ctxt)
2686 {
2687         Channel *c = NULL;
2688         u_short host_port;
2689         char *host, *originator_string;
2690         int remote_id;
2691
2692         remote_id = packet_get_int();
2693         host = packet_get_string(NULL);
2694         host_port = packet_get_int();
2695
2696         if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
2697                 originator_string = packet_get_string(NULL);
2698         } else {
2699                 originator_string = xstrdup("unknown (remote did not supply name)");
2700         }
2701         packet_check_eom();
2702         c = channel_connect_to_port(host, host_port,
2703             "connected socket", originator_string);
2704         free(originator_string);
2705         free(host);
2706         if (c == NULL) {
2707                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
2708                 packet_put_int(remote_id);
2709                 packet_send();
2710         } else
2711                 c->remote_id = remote_id;
2712         return 0;
2713 }
2714
2715 /* ARGSUSED */
2716 int
2717 channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
2718 {
2719         Channel *c;
2720         struct channel_confirm *cc;
2721         int id;
2722
2723         /* Reset keepalive timeout */
2724         packet_set_alive_timeouts(0);
2725
2726         id = packet_get_int();
2727         packet_check_eom();
2728
2729         debug2("channel_input_status_confirm: type %d id %d", type, id);
2730
2731         if ((c = channel_lookup(id)) == NULL) {
2732                 logit("channel_input_status_confirm: %d: unknown", id);
2733                 return 0;
2734         }
2735         if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
2736                 return 0;
2737         cc->cb(type, c, cc->ctx);
2738         TAILQ_REMOVE(&c->status_confirms, cc, entry);
2739         explicit_bzero(cc, sizeof(*cc));
2740         free(cc);
2741         return 0;
2742 }
2743
2744 /* -- tcp forwarding */
2745
2746 void
2747 channel_set_af(int af)
2748 {
2749         IPv4or6 = af;
2750 }
2751
2752
2753 /*
2754  * Determine whether or not a port forward listens to loopback, the
2755  * specified address or wildcard. On the client, a specified bind
2756  * address will always override gateway_ports. On the server, a
2757  * gateway_ports of 1 (``yes'') will override the client's specification
2758  * and force a wildcard bind, whereas a value of 2 (``clientspecified'')
2759  * will bind to whatever address the client asked for.
2760  *
2761  * Special-case listen_addrs are:
2762  *
2763  * "0.0.0.0"               -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
2764  * "" (empty string), "*"  -> wildcard v4/v6
2765  * "localhost"             -> loopback v4/v6
2766  * "127.0.0.1" / "::1"     -> accepted even if gateway_ports isn't set
2767  */
2768 static const char *
2769 channel_fwd_bind_addr(const char *listen_addr, int *wildcardp,
2770     int is_client, struct ForwardOptions *fwd_opts)
2771 {
2772         const char *addr = NULL;
2773         int wildcard = 0;
2774
2775         if (listen_addr == NULL) {
2776                 /* No address specified: default to gateway_ports setting */
2777                 if (fwd_opts->gateway_ports)
2778                         wildcard = 1;
2779         } else if (fwd_opts->gateway_ports || is_client) {
2780                 if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
2781                     strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
2782                     *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
2783                     (!is_client && fwd_opts->gateway_ports == 1)) {
2784                         wildcard = 1;
2785                         /*
2786                          * Notify client if they requested a specific listen
2787                          * address and it was overridden.
2788                          */
2789                         if (*listen_addr != '\0' &&
2790                             strcmp(listen_addr, "0.0.0.0") != 0 &&
2791                             strcmp(listen_addr, "*") != 0) {
2792                                 packet_send_debug("Forwarding listen address "
2793                                     "\"%s\" overridden by server "
2794                                     "GatewayPorts", listen_addr);
2795                         }
2796                 } else if (strcmp(listen_addr, "localhost") != 0 ||
2797                     strcmp(listen_addr, "127.0.0.1") == 0 ||
2798                     strcmp(listen_addr, "::1") == 0) {
2799                         /* Accept localhost address when GatewayPorts=yes */
2800                         addr = listen_addr;
2801                 }
2802         } else if (strcmp(listen_addr, "127.0.0.1") == 0 ||
2803             strcmp(listen_addr, "::1") == 0) {
2804                 /*
2805                  * If a specific IPv4/IPv6 localhost address has been
2806                  * requested then accept it even if gateway_ports is in
2807                  * effect. This allows the client to prefer IPv4 or IPv6.
2808                  */
2809                 addr = listen_addr;
2810         }
2811         if (wildcardp != NULL)
2812                 *wildcardp = wildcard;
2813         return addr;
2814 }
2815
2816 static int
2817 channel_setup_fwd_listener_tcpip(int type, struct Forward *fwd,
2818     int *allocated_listen_port, struct ForwardOptions *fwd_opts)
2819 {
2820         Channel *c;
2821         int sock, r, success = 0, wildcard = 0, is_client;
2822         struct addrinfo hints, *ai, *aitop;
2823         const char *host, *addr;
2824         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
2825         in_port_t *lport_p;
2826
2827         is_client = (type == SSH_CHANNEL_PORT_LISTENER);
2828
2829         if (is_client && fwd->connect_path != NULL) {
2830                 host = fwd->connect_path;
2831         } else {
2832                 host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
2833                     fwd->listen_host : fwd->connect_host;
2834                 if (host == NULL) {
2835                         error("No forward host name.");
2836                         return 0;
2837                 }
2838                 if (strlen(host) >= NI_MAXHOST) {
2839                         error("Forward host name too long.");
2840                         return 0;
2841                 }
2842         }
2843
2844         /* Determine the bind address, cf. channel_fwd_bind_addr() comment */
2845         addr = channel_fwd_bind_addr(fwd->listen_host, &wildcard,
2846             is_client, fwd_opts);
2847         debug3("%s: type %d wildcard %d addr %s", __func__,
2848             type, wildcard, (addr == NULL) ? "NULL" : addr);
2849
2850         /*
2851          * getaddrinfo returns a loopback address if the hostname is
2852          * set to NULL and hints.ai_flags is not AI_PASSIVE
2853          */
2854         memset(&hints, 0, sizeof(hints));
2855         hints.ai_family = IPv4or6;
2856         hints.ai_flags = wildcard ? AI_PASSIVE : 0;
2857         hints.ai_socktype = SOCK_STREAM;
2858         snprintf(strport, sizeof strport, "%d", fwd->listen_port);
2859         if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
2860                 if (addr == NULL) {
2861                         /* This really shouldn't happen */
2862                         packet_disconnect("getaddrinfo: fatal error: %s",
2863                             ssh_gai_strerror(r));
2864                 } else {
2865                         error("%s: getaddrinfo(%.64s): %s", __func__, addr,
2866                             ssh_gai_strerror(r));
2867                 }
2868                 return 0;
2869         }
2870         if (allocated_listen_port != NULL)
2871                 *allocated_listen_port = 0;
2872         for (ai = aitop; ai; ai = ai->ai_next) {
2873                 switch (ai->ai_family) {
2874                 case AF_INET:
2875                         lport_p = &((struct sockaddr_in *)ai->ai_addr)->
2876                             sin_port;
2877                         break;
2878                 case AF_INET6:
2879                         lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
2880                             sin6_port;
2881                         break;
2882                 default:
2883                         continue;
2884                 }
2885                 /*
2886                  * If allocating a port for -R forwards, then use the
2887                  * same port for all address families.
2888                  */
2889                 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 &&
2890                     allocated_listen_port != NULL && *allocated_listen_port > 0)
2891                         *lport_p = htons(*allocated_listen_port);
2892
2893                 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
2894                     strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
2895                         error("%s: getnameinfo failed", __func__);
2896                         continue;
2897                 }
2898                 /* Create a port to listen for the host. */
2899                 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
2900                 if (sock < 0) {
2901                         /* this is no error since kernel may not support ipv6 */
2902                         verbose("socket: %.100s", strerror(errno));
2903                         continue;
2904                 }
2905
2906                 channel_set_reuseaddr(sock);
2907                 if (ai->ai_family == AF_INET6)
2908                         sock_set_v6only(sock);
2909
2910                 debug("Local forwarding listening on %s port %s.",
2911                     ntop, strport);
2912
2913                 /* Bind the socket to the address. */
2914                 if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
2915                         /* address can be in use ipv6 address is already bound */
2916                         if (!ai->ai_next)
2917                                 error("bind: %.100s", strerror(errno));
2918                         else
2919                                 verbose("bind: %.100s", strerror(errno));
2920
2921                         close(sock);
2922                         continue;
2923                 }
2924                 /* Start listening for connections on the socket. */
2925                 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
2926                         error("listen: %.100s", strerror(errno));
2927                         close(sock);
2928                         continue;
2929                 }
2930
2931                 /*
2932                  * fwd->listen_port == 0 requests a dynamically allocated port -
2933                  * record what we got.
2934                  */
2935                 if (type == SSH_CHANNEL_RPORT_LISTENER && fwd->listen_port == 0 &&
2936                     allocated_listen_port != NULL &&
2937                     *allocated_listen_port == 0) {
2938                         *allocated_listen_port = get_sock_port(sock, 1);
2939                         debug("Allocated listen port %d",
2940                             *allocated_listen_port);
2941                 }
2942
2943                 /* Allocate a channel number for the socket. */
2944                 c = channel_new("port listener", type, sock, sock, -1,
2945                     CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
2946                     0, "port listener", 1);
2947                 c->path = xstrdup(host);
2948                 c->host_port = fwd->connect_port;
2949                 c->listening_addr = addr == NULL ? NULL : xstrdup(addr);
2950                 if (fwd->listen_port == 0 && allocated_listen_port != NULL &&
2951                     !(datafellows & SSH_BUG_DYNAMIC_RPORT))
2952                         c->listening_port = *allocated_listen_port;
2953                 else
2954                         c->listening_port = fwd->listen_port;
2955                 success = 1;
2956         }
2957         if (success == 0)
2958                 error("%s: cannot listen to port: %d", __func__,
2959                     fwd->listen_port);
2960         freeaddrinfo(aitop);
2961         return success;
2962 }
2963
2964 static int
2965 channel_setup_fwd_listener_streamlocal(int type, struct Forward *fwd,
2966     struct ForwardOptions *fwd_opts)
2967 {
2968         struct sockaddr_un sunaddr;
2969         const char *path;
2970         Channel *c;
2971         int port, sock;
2972         mode_t omask;
2973
2974         switch (type) {
2975         case SSH_CHANNEL_UNIX_LISTENER:
2976                 if (fwd->connect_path != NULL) {
2977                         if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) {
2978                                 error("Local connecting path too long: %s",
2979                                     fwd->connect_path);
2980                                 return 0;
2981                         }
2982                         path = fwd->connect_path;
2983                         port = PORT_STREAMLOCAL;
2984                 } else {
2985                         if (fwd->connect_host == NULL) {
2986                                 error("No forward host name.");
2987                                 return 0;
2988                         }
2989                         if (strlen(fwd->connect_host) >= NI_MAXHOST) {
2990                                 error("Forward host name too long.");
2991                                 return 0;
2992                         }
2993                         path = fwd->connect_host;
2994                         port = fwd->connect_port;
2995                 }
2996                 break;
2997         case SSH_CHANNEL_RUNIX_LISTENER:
2998                 path = fwd->listen_path;
2999                 port = PORT_STREAMLOCAL;
3000                 break;
3001         default:
3002                 error("%s: unexpected channel type %d", __func__, type);
3003                 return 0;
3004         }
3005
3006         if (fwd->listen_path == NULL) {
3007                 error("No forward path name.");
3008                 return 0;
3009         }
3010         if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) {
3011                 error("Local listening path too long: %s", fwd->listen_path);
3012                 return 0;
3013         }
3014
3015         debug3("%s: type %d path %s", __func__, type, fwd->listen_path);
3016
3017         /* Start a Unix domain listener. */
3018         omask = umask(fwd_opts->streamlocal_bind_mask);
3019         sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG,
3020             fwd_opts->streamlocal_bind_unlink);
3021         umask(omask);
3022         if (sock < 0)
3023                 return 0;
3024
3025         debug("Local forwarding listening on path %s.", fwd->listen_path);
3026
3027         /* Allocate a channel number for the socket. */
3028         c = channel_new("unix listener", type, sock, sock, -1,
3029             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
3030             0, "unix listener", 1);
3031         c->path = xstrdup(path);
3032         c->host_port = port;
3033         c->listening_port = PORT_STREAMLOCAL;
3034         c->listening_addr = xstrdup(fwd->listen_path);
3035         return 1;
3036 }
3037
3038 static int
3039 channel_cancel_rport_listener_tcpip(const char *host, u_short port)
3040 {
3041         u_int i;
3042         int found = 0;
3043
3044         for (i = 0; i < channels_alloc; i++) {
3045                 Channel *c = channels[i];
3046                 if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER)
3047                         continue;
3048                 if (strcmp(c->path, host) == 0 && c->listening_port == port) {
3049                         debug2("%s: close channel %d", __func__, i);
3050                         channel_free(c);
3051                         found = 1;
3052                 }
3053         }
3054
3055         return (found);
3056 }
3057
3058 static int
3059 channel_cancel_rport_listener_streamlocal(const char *path)
3060 {
3061         u_int i;
3062         int found = 0;
3063
3064         for (i = 0; i < channels_alloc; i++) {
3065                 Channel *c = channels[i];
3066                 if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER)
3067                         continue;
3068                 if (c->path == NULL)
3069                         continue;
3070                 if (strcmp(c->path, path) == 0) {
3071                         debug2("%s: close channel %d", __func__, i);
3072                         channel_free(c);
3073                         found = 1;
3074                 }
3075         }
3076
3077         return (found);
3078 }
3079
3080 int
3081 channel_cancel_rport_listener(struct Forward *fwd)
3082 {
3083         if (fwd->listen_path != NULL)
3084                 return channel_cancel_rport_listener_streamlocal(fwd->listen_path);
3085         else
3086                 return channel_cancel_rport_listener_tcpip(fwd->listen_host, fwd->listen_port);
3087 }
3088
3089 static int
3090 channel_cancel_lport_listener_tcpip(const char *lhost, u_short lport,
3091     int cport, struct ForwardOptions *fwd_opts)
3092 {
3093         u_int i;
3094         int found = 0;
3095         const char *addr = channel_fwd_bind_addr(lhost, NULL, 1, fwd_opts);
3096
3097         for (i = 0; i < channels_alloc; i++) {
3098                 Channel *c = channels[i];
3099                 if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER)
3100                         continue;
3101                 if (c->listening_port != lport)
3102                         continue;
3103                 if (cport == CHANNEL_CANCEL_PORT_STATIC) {
3104                         /* skip dynamic forwardings */
3105                         if (c->host_port == 0)
3106                                 continue;
3107                 } else {
3108                         if (c->host_port != cport)
3109                                 continue;
3110                 }
3111                 if ((c->listening_addr == NULL && addr != NULL) ||
3112                     (c->listening_addr != NULL && addr == NULL))
3113                         continue;
3114                 if (addr == NULL || strcmp(c->listening_addr, addr) == 0) {
3115                         debug2("%s: close channel %d", __func__, i);
3116                         channel_free(c);
3117                         found = 1;
3118                 }
3119         }
3120
3121         return (found);
3122 }
3123
3124 static int
3125 channel_cancel_lport_listener_streamlocal(const char *path)
3126 {
3127         u_int i;
3128         int found = 0;
3129
3130         if (path == NULL) {
3131                 error("%s: no path specified.", __func__);
3132                 return 0;
3133         }
3134
3135         for (i = 0; i < channels_alloc; i++) {
3136                 Channel *c = channels[i];
3137                 if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER)
3138                         continue;
3139                 if (c->listening_addr == NULL)
3140                         continue;
3141                 if (strcmp(c->listening_addr, path) == 0) {
3142                         debug2("%s: close channel %d", __func__, i);
3143                         channel_free(c);
3144                         found = 1;
3145                 }
3146         }
3147
3148         return (found);
3149 }
3150
3151 int
3152 channel_cancel_lport_listener(struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts)
3153 {
3154         if (fwd->listen_path != NULL)
3155                 return channel_cancel_lport_listener_streamlocal(fwd->listen_path);
3156         else
3157                 return channel_cancel_lport_listener_tcpip(fwd->listen_host, fwd->listen_port, cport, fwd_opts);
3158 }
3159
3160 /* protocol local port fwd, used by ssh (and sshd in v1) */
3161 int
3162 channel_setup_local_fwd_listener(struct Forward *fwd, struct ForwardOptions *fwd_opts)
3163 {
3164         if (fwd->listen_path != NULL) {
3165                 return channel_setup_fwd_listener_streamlocal(
3166                     SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts);
3167         } else {
3168                 return channel_setup_fwd_listener_tcpip(SSH_CHANNEL_PORT_LISTENER,
3169                     fwd, NULL, fwd_opts);
3170         }
3171 }
3172
3173 /* protocol v2 remote port fwd, used by sshd */
3174 int
3175 channel_setup_remote_fwd_listener(struct Forward *fwd,
3176     int *allocated_listen_port, struct ForwardOptions *fwd_opts)
3177 {
3178         if (fwd->listen_path != NULL) {
3179                 return channel_setup_fwd_listener_streamlocal(
3180                     SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts);
3181         } else {
3182                 return channel_setup_fwd_listener_tcpip(
3183                     SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port,
3184                     fwd_opts);
3185         }
3186 }
3187
3188 /*
3189  * Translate the requested rfwd listen host to something usable for
3190  * this server.
3191  */
3192 static const char *
3193 channel_rfwd_bind_host(const char *listen_host)
3194 {
3195         if (listen_host == NULL) {
3196                 if (datafellows & SSH_BUG_RFWD_ADDR)
3197                         return "127.0.0.1";
3198                 else
3199                         return "localhost";
3200         } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) {
3201                 if (datafellows & SSH_BUG_RFWD_ADDR)
3202                         return "0.0.0.0";
3203                 else
3204                         return "";
3205         } else
3206                 return listen_host;
3207 }
3208
3209 /*
3210  * Initiate forwarding of connections to port "port" on remote host through
3211  * the secure channel to host:port from local side.
3212  * Returns handle (index) for updating the dynamic listen port with
3213  * channel_update_permitted_opens().
3214  */
3215 int
3216 channel_request_remote_forwarding(struct Forward *fwd)
3217 {
3218         int type, success = 0, idx = -1;
3219
3220         /* Send the forward request to the remote side. */
3221         if (compat20) {
3222                 packet_start(SSH2_MSG_GLOBAL_REQUEST);
3223                 if (fwd->listen_path != NULL) {
3224                     packet_put_cstring("streamlocal-forward@openssh.com");
3225                     packet_put_char(1);         /* boolean: want reply */
3226                     packet_put_cstring(fwd->listen_path);
3227                 } else {
3228                     packet_put_cstring("tcpip-forward");
3229                     packet_put_char(1);         /* boolean: want reply */
3230                     packet_put_cstring(channel_rfwd_bind_host(fwd->listen_host));
3231                     packet_put_int(fwd->listen_port);
3232                 }
3233                 packet_send();
3234                 packet_write_wait();
3235                 /* Assume that server accepts the request */
3236                 success = 1;
3237         } else if (fwd->listen_path == NULL) {
3238                 packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
3239                 packet_put_int(fwd->listen_port);
3240                 packet_put_cstring(fwd->connect_host);
3241                 packet_put_int(fwd->connect_port);
3242                 packet_send();
3243                 packet_write_wait();
3244
3245                 /* Wait for response from the remote side. */
3246                 type = packet_read();
3247                 switch (type) {
3248                 case SSH_SMSG_SUCCESS:
3249                         success = 1;
3250                         break;
3251                 case SSH_SMSG_FAILURE:
3252                         break;
3253                 default:
3254                         /* Unknown packet */
3255                         packet_disconnect("Protocol error for port forward request:"
3256                             "received packet type %d.", type);
3257                 }
3258         } else {
3259                 logit("Warning: Server does not support remote stream local forwarding.");
3260         }
3261         if (success) {
3262                 /* Record that connection to this host/port is permitted. */
3263                 permitted_opens = xreallocarray(permitted_opens,
3264                     num_permitted_opens + 1, sizeof(*permitted_opens));
3265                 idx = num_permitted_opens++;
3266                 if (fwd->connect_path != NULL) {
3267                         permitted_opens[idx].host_to_connect =
3268                             xstrdup(fwd->connect_path);
3269                         permitted_opens[idx].port_to_connect =
3270                             PORT_STREAMLOCAL;
3271                 } else {
3272                         permitted_opens[idx].host_to_connect =
3273                             xstrdup(fwd->connect_host);
3274                         permitted_opens[idx].port_to_connect =
3275                             fwd->connect_port;
3276                 }
3277                 if (fwd->listen_path != NULL) {
3278                         permitted_opens[idx].listen_host = NULL;
3279                         permitted_opens[idx].listen_path =
3280                             xstrdup(fwd->listen_path);
3281                         permitted_opens[idx].listen_port = PORT_STREAMLOCAL;
3282                 } else {
3283                         permitted_opens[idx].listen_host =
3284                             fwd->listen_host ? xstrdup(fwd->listen_host) : NULL;
3285                         permitted_opens[idx].listen_path = NULL;
3286                         permitted_opens[idx].listen_port = fwd->listen_port;
3287                 }
3288         }
3289         return (idx);
3290 }
3291
3292 static int
3293 open_match(ForwardPermission *allowed_open, const char *requestedhost,
3294     int requestedport)
3295 {
3296         if (allowed_open->host_to_connect == NULL)
3297                 return 0;
3298         if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT &&
3299             allowed_open->port_to_connect != requestedport)
3300                 return 0;
3301         if (strcmp(allowed_open->host_to_connect, requestedhost) != 0)
3302                 return 0;
3303         return 1;
3304 }
3305
3306 /*
3307  * Note that in the listen host/port case
3308  * we don't support FWD_PERMIT_ANY_PORT and
3309  * need to translate between the configured-host (listen_host)
3310  * and what we've sent to the remote server (channel_rfwd_bind_host)
3311  */
3312 static int
3313 open_listen_match_tcpip(ForwardPermission *allowed_open,
3314     const char *requestedhost, u_short requestedport, int translate)
3315 {
3316         const char *allowed_host;
3317
3318         if (allowed_open->host_to_connect == NULL)
3319                 return 0;
3320         if (allowed_open->listen_port != requestedport)
3321                 return 0;
3322         if (!translate && allowed_open->listen_host == NULL &&
3323             requestedhost == NULL)
3324                 return 1;
3325         allowed_host = translate ?
3326             channel_rfwd_bind_host(allowed_open->listen_host) :
3327             allowed_open->listen_host;
3328         if (allowed_host == NULL ||
3329             strcmp(allowed_host, requestedhost) != 0)
3330                 return 0;
3331         return 1;
3332 }
3333
3334 static int
3335 open_listen_match_streamlocal(ForwardPermission *allowed_open,
3336     const char *requestedpath)
3337 {
3338         if (allowed_open->host_to_connect == NULL)
3339                 return 0;
3340         if (allowed_open->listen_port != PORT_STREAMLOCAL)
3341                 return 0;
3342         if (allowed_open->listen_path == NULL ||
3343             strcmp(allowed_open->listen_path, requestedpath) != 0)
3344                 return 0;
3345         return 1;
3346 }
3347
3348 /*
3349  * Request cancellation of remote forwarding of connection host:port from
3350  * local side.
3351  */
3352 static int
3353 channel_request_rforward_cancel_tcpip(const char *host, u_short port)
3354 {
3355         int i;
3356
3357         if (!compat20)
3358                 return -1;
3359
3360         for (i = 0; i < num_permitted_opens; i++) {
3361                 if (open_listen_match_tcpip(&permitted_opens[i], host, port, 0))
3362                         break;
3363         }
3364         if (i >= num_permitted_opens) {
3365                 debug("%s: requested forward not found", __func__);
3366                 return -1;
3367         }
3368         packet_start(SSH2_MSG_GLOBAL_REQUEST);
3369         packet_put_cstring("cancel-tcpip-forward");
3370         packet_put_char(0);
3371         packet_put_cstring(channel_rfwd_bind_host(host));
3372         packet_put_int(port);
3373         packet_send();
3374
3375         permitted_opens[i].listen_port = 0;
3376         permitted_opens[i].port_to_connect = 0;
3377         free(permitted_opens[i].host_to_connect);
3378         permitted_opens[i].host_to_connect = NULL;
3379         free(permitted_opens[i].listen_host);
3380         permitted_opens[i].listen_host = NULL;
3381         permitted_opens[i].listen_path = NULL;
3382
3383         return 0;
3384 }
3385
3386 /*
3387  * Request cancellation of remote forwarding of Unix domain socket
3388  * path from local side.
3389  */
3390 static int
3391 channel_request_rforward_cancel_streamlocal(const char *path)
3392 {
3393         int i;
3394
3395         if (!compat20)
3396                 return -1;
3397
3398         for (i = 0; i < num_permitted_opens; i++) {
3399                 if (open_listen_match_streamlocal(&permitted_opens[i], path))
3400                         break;
3401         }
3402         if (i >= num_permitted_opens) {
3403                 debug("%s: requested forward not found", __func__);
3404                 return -1;
3405         }
3406         packet_start(SSH2_MSG_GLOBAL_REQUEST);
3407         packet_put_cstring("cancel-streamlocal-forward@openssh.com");
3408         packet_put_char(0);
3409         packet_put_cstring(path);
3410         packet_send();
3411
3412         permitted_opens[i].listen_port = 0;
3413         permitted_opens[i].port_to_connect = 0;
3414         free(permitted_opens[i].host_to_connect);
3415         permitted_opens[i].host_to_connect = NULL;
3416         permitted_opens[i].listen_host = NULL;
3417         free(permitted_opens[i].listen_path);
3418         permitted_opens[i].listen_path = NULL;
3419
3420         return 0;
3421 }
3422
3423 /*
3424  * Request cancellation of remote forwarding of a connection from local side.
3425  */
3426 int
3427 channel_request_rforward_cancel(struct Forward *fwd)
3428 {
3429         if (fwd->listen_path != NULL) {
3430                 return (channel_request_rforward_cancel_streamlocal(
3431                     fwd->listen_path));
3432         } else {
3433                 return (channel_request_rforward_cancel_tcpip(fwd->listen_host,
3434                     fwd->listen_port ? fwd->listen_port : fwd->allocated_port));
3435         }
3436 }
3437
3438 /*
3439  * This is called after receiving CHANNEL_FORWARDING_REQUEST.  This initates
3440  * listening for the port, and sends back a success reply (or disconnect
3441  * message if there was an error).
3442  */
3443 int
3444 channel_input_port_forward_request(int is_root, struct ForwardOptions *fwd_opts)
3445 {
3446         int success = 0;
3447         struct Forward fwd;
3448
3449         /* Get arguments from the packet. */
3450         memset(&fwd, 0, sizeof(fwd));
3451         fwd.listen_port = packet_get_int();
3452         fwd.connect_host = packet_get_string(NULL);
3453         fwd.connect_port = packet_get_int();
3454
3455 #ifndef HAVE_CYGWIN
3456         /*
3457          * Check that an unprivileged user is not trying to forward a
3458          * privileged port.
3459          */
3460         if (fwd.listen_port < IPPORT_RESERVED && !is_root)
3461                 packet_disconnect(
3462                     "Requested forwarding of port %d but user is not root.",
3463                     fwd.listen_port);
3464         if (fwd.connect_port == 0)
3465                 packet_disconnect("Dynamic forwarding denied.");
3466 #endif
3467
3468         /* Initiate forwarding */
3469         success = channel_setup_local_fwd_listener(&fwd, fwd_opts);
3470
3471         /* Free the argument string. */
3472         free(fwd.connect_host);
3473
3474         return (success ? 0 : -1);
3475 }
3476
3477 /*
3478  * Permits opening to any host/port if permitted_opens[] is empty.  This is
3479  * usually called by the server, because the user could connect to any port
3480  * anyway, and the server has no way to know but to trust the client anyway.
3481  */
3482 void
3483 channel_permit_all_opens(void)
3484 {
3485         if (num_permitted_opens == 0)
3486                 all_opens_permitted = 1;
3487 }
3488
3489 void
3490 channel_add_permitted_opens(char *host, int port)
3491 {
3492         debug("allow port forwarding to host %s port %d", host, port);
3493
3494         permitted_opens = xreallocarray(permitted_opens,
3495             num_permitted_opens + 1, sizeof(*permitted_opens));
3496         permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
3497         permitted_opens[num_permitted_opens].port_to_connect = port;
3498         permitted_opens[num_permitted_opens].listen_host = NULL;
3499         permitted_opens[num_permitted_opens].listen_path = NULL;
3500         permitted_opens[num_permitted_opens].listen_port = 0;
3501         num_permitted_opens++;
3502
3503         all_opens_permitted = 0;
3504 }
3505
3506 /*
3507  * Update the listen port for a dynamic remote forward, after
3508  * the actual 'newport' has been allocated. If 'newport' < 0 is
3509  * passed then they entry will be invalidated.
3510  */
3511 void
3512 channel_update_permitted_opens(int idx, int newport)
3513 {
3514         if (idx < 0 || idx >= num_permitted_opens) {
3515                 debug("channel_update_permitted_opens: index out of range:"
3516                     " %d num_permitted_opens %d", idx, num_permitted_opens);
3517                 return;
3518         }
3519         debug("%s allowed port %d for forwarding to host %s port %d",
3520             newport > 0 ? "Updating" : "Removing",
3521             newport,
3522             permitted_opens[idx].host_to_connect,
3523             permitted_opens[idx].port_to_connect);
3524         if (newport >= 0)  {
3525                 permitted_opens[idx].listen_port =
3526                     (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport;
3527         } else {
3528                 permitted_opens[idx].listen_port = 0;
3529                 permitted_opens[idx].port_to_connect = 0;
3530                 free(permitted_opens[idx].host_to_connect);
3531                 permitted_opens[idx].host_to_connect = NULL;
3532                 free(permitted_opens[idx].listen_host);
3533                 permitted_opens[idx].listen_host = NULL;
3534                 free(permitted_opens[idx].listen_path);
3535                 permitted_opens[idx].listen_path = NULL;
3536         }
3537 }
3538
3539 int
3540 channel_add_adm_permitted_opens(char *host, int port)
3541 {
3542         debug("config allows port forwarding to host %s port %d", host, port);
3543
3544         permitted_adm_opens = xreallocarray(permitted_adm_opens,
3545             num_adm_permitted_opens + 1, sizeof(*permitted_adm_opens));
3546         permitted_adm_opens[num_adm_permitted_opens].host_to_connect
3547              = xstrdup(host);
3548         permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
3549         permitted_adm_opens[num_adm_permitted_opens].listen_host = NULL;
3550         permitted_adm_opens[num_adm_permitted_opens].listen_path = NULL;
3551         permitted_adm_opens[num_adm_permitted_opens].listen_port = 0;
3552         return ++num_adm_permitted_opens;
3553 }
3554
3555 void
3556 channel_disable_adm_local_opens(void)
3557 {
3558         channel_clear_adm_permitted_opens();
3559         permitted_adm_opens = xcalloc(sizeof(*permitted_adm_opens), 1);
3560         permitted_adm_opens[num_adm_permitted_opens].host_to_connect = NULL;
3561         num_adm_permitted_opens = 1;
3562 }
3563
3564 void
3565 channel_clear_permitted_opens(void)
3566 {
3567         int i;
3568
3569         for (i = 0; i < num_permitted_opens; i++) {
3570                 free(permitted_opens[i].host_to_connect);
3571                 free(permitted_opens[i].listen_host);
3572                 free(permitted_opens[i].listen_path);
3573         }
3574         free(permitted_opens);
3575         permitted_opens = NULL;
3576         num_permitted_opens = 0;
3577 }
3578
3579 void
3580 channel_clear_adm_permitted_opens(void)
3581 {
3582         int i;
3583
3584         for (i = 0; i < num_adm_permitted_opens; i++) {
3585                 free(permitted_adm_opens[i].host_to_connect);
3586                 free(permitted_adm_opens[i].listen_host);
3587                 free(permitted_adm_opens[i].listen_path);
3588         }
3589         free(permitted_adm_opens);
3590         permitted_adm_opens = NULL;
3591         num_adm_permitted_opens = 0;
3592 }
3593
3594 void
3595 channel_print_adm_permitted_opens(void)
3596 {
3597         int i;
3598
3599         printf("permitopen");
3600         if (num_adm_permitted_opens == 0) {
3601                 printf(" any\n");
3602                 return;
3603         }
3604         for (i = 0; i < num_adm_permitted_opens; i++)
3605                 if (permitted_adm_opens[i].host_to_connect == NULL)
3606                         printf(" none");
3607                 else
3608                         printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
3609                             permitted_adm_opens[i].port_to_connect);
3610         printf("\n");
3611 }
3612
3613 /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */
3614 int
3615 permitopen_port(const char *p)
3616 {
3617         int port;
3618
3619         if (strcmp(p, "*") == 0)
3620                 return FWD_PERMIT_ANY_PORT;
3621         if ((port = a2port(p)) > 0)
3622                 return port;
3623         return -1;
3624 }
3625
3626 /* Try to start non-blocking connect to next host in cctx list */
3627 static int
3628 connect_next(struct channel_connect *cctx)
3629 {
3630         int sock, saved_errno;
3631         struct sockaddr_un *sunaddr;
3632         char ntop[NI_MAXHOST], strport[MAX(NI_MAXSERV,sizeof(sunaddr->sun_path))];
3633
3634         for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
3635                 switch (cctx->ai->ai_family) {
3636                 case AF_UNIX:
3637                         /* unix:pathname instead of host:port */
3638                         sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr;
3639                         strlcpy(ntop, "unix", sizeof(ntop));
3640                         strlcpy(strport, sunaddr->sun_path, sizeof(strport));
3641                         break;
3642                 case AF_INET:
3643                 case AF_INET6:
3644                         if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
3645                             ntop, sizeof(ntop), strport, sizeof(strport),
3646                             NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
3647                                 error("connect_next: getnameinfo failed");
3648                                 continue;
3649                         }
3650                         break;
3651                 default:
3652                         continue;
3653                 }
3654                 if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
3655                     cctx->ai->ai_protocol)) == -1) {
3656                         if (cctx->ai->ai_next == NULL)
3657                                 error("socket: %.100s", strerror(errno));
3658                         else
3659                                 verbose("socket: %.100s", strerror(errno));
3660                         continue;
3661                 }
3662                 if (set_nonblock(sock) == -1)
3663                         fatal("%s: set_nonblock(%d)", __func__, sock);
3664                 if (connect(sock, cctx->ai->ai_addr,
3665                     cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
3666                         debug("connect_next: host %.100s ([%.100s]:%s): "
3667                             "%.100s", cctx->host, ntop, strport,
3668                             strerror(errno));
3669                         saved_errno = errno;
3670                         close(sock);
3671                         errno = saved_errno;
3672                         continue;       /* fail -- try next */
3673                 }
3674                 if (cctx->ai->ai_family != AF_UNIX)
3675                         set_nodelay(sock);
3676                 debug("connect_next: host %.100s ([%.100s]:%s) "
3677                     "in progress, fd=%d", cctx->host, ntop, strport, sock);
3678                 cctx->ai = cctx->ai->ai_next;
3679                 return sock;
3680         }
3681         return -1;
3682 }
3683
3684 static void
3685 channel_connect_ctx_free(struct channel_connect *cctx)
3686 {
3687         free(cctx->host);
3688         if (cctx->aitop) {
3689                 if (cctx->aitop->ai_family == AF_UNIX)
3690                         free(cctx->aitop);
3691                 else
3692                         freeaddrinfo(cctx->aitop);
3693         }
3694         memset(cctx, 0, sizeof(*cctx));
3695 }
3696
3697 /* Return CONNECTING channel to remote host:port or local socket path */
3698 static Channel *
3699 connect_to(const char *name, int port, char *ctype, char *rname)
3700 {
3701         struct addrinfo hints;
3702         int gaierr;
3703         int sock = -1;
3704         char strport[NI_MAXSERV];
3705         struct channel_connect cctx;
3706         Channel *c;
3707
3708         memset(&cctx, 0, sizeof(cctx));
3709
3710         if (port == PORT_STREAMLOCAL) {
3711                 struct sockaddr_un *sunaddr;
3712                 struct addrinfo *ai;
3713
3714                 if (strlen(name) > sizeof(sunaddr->sun_path)) {
3715                         error("%.100s: %.100s", name, strerror(ENAMETOOLONG));
3716                         return (NULL);
3717                 }
3718
3719                 /*
3720                  * Fake up a struct addrinfo for AF_UNIX connections.
3721                  * channel_connect_ctx_free() must check ai_family
3722                  * and use free() not freeaddirinfo() for AF_UNIX.
3723                  */
3724                 ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr));
3725                 memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr));
3726                 ai->ai_addr = (struct sockaddr *)(ai + 1);
3727                 ai->ai_addrlen = sizeof(*sunaddr);
3728                 ai->ai_family = AF_UNIX;
3729                 ai->ai_socktype = SOCK_STREAM;
3730                 ai->ai_protocol = PF_UNSPEC;
3731                 sunaddr = (struct sockaddr_un *)ai->ai_addr;
3732                 sunaddr->sun_family = AF_UNIX;
3733                 strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path));
3734                 cctx.aitop = ai;
3735         } else {
3736                 memset(&hints, 0, sizeof(hints));
3737                 hints.ai_family = IPv4or6;
3738                 hints.ai_socktype = SOCK_STREAM;
3739                 snprintf(strport, sizeof strport, "%d", port);
3740                 if ((gaierr = getaddrinfo(name, strport, &hints, &cctx.aitop)) != 0) {
3741                         error("connect_to %.100s: unknown host (%s)", name,
3742                             ssh_gai_strerror(gaierr));
3743                         return NULL;
3744                 }
3745         }
3746
3747         cctx.host = xstrdup(name);
3748         cctx.port = port;
3749         cctx.ai = cctx.aitop;
3750
3751         if ((sock = connect_next(&cctx)) == -1) {
3752                 error("connect to %.100s port %d failed: %s",
3753                     name, port, strerror(errno));
3754                 channel_connect_ctx_free(&cctx);
3755                 return NULL;
3756         }
3757         c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
3758             CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
3759         c->connect_ctx = cctx;
3760         return c;
3761 }
3762
3763 Channel *
3764 channel_connect_by_listen_address(const char *listen_host,
3765     u_short listen_port, char *ctype, char *rname)
3766 {
3767         int i;
3768
3769         for (i = 0; i < num_permitted_opens; i++) {
3770                 if (open_listen_match_tcpip(&permitted_opens[i], listen_host,
3771                     listen_port, 1)) {
3772                         return connect_to(
3773                             permitted_opens[i].host_to_connect,
3774                             permitted_opens[i].port_to_connect, ctype, rname);
3775                 }
3776         }
3777         error("WARNING: Server requests forwarding for unknown listen_port %d",
3778             listen_port);
3779         return NULL;
3780 }
3781
3782 Channel *
3783 channel_connect_by_listen_path(const char *path, char *ctype, char *rname)
3784 {
3785         int i;
3786
3787         for (i = 0; i < num_permitted_opens; i++) {
3788                 if (open_listen_match_streamlocal(&permitted_opens[i], path)) {
3789                         return connect_to(
3790                             permitted_opens[i].host_to_connect,
3791                             permitted_opens[i].port_to_connect, ctype, rname);
3792                 }
3793         }
3794         error("WARNING: Server requests forwarding for unknown path %.100s",
3795             path);
3796         return NULL;
3797 }
3798
3799 /* Check if connecting to that port is permitted and connect. */
3800 Channel *
3801 channel_connect_to_port(const char *host, u_short port, char *ctype, char *rname)
3802 {
3803         int i, permit, permit_adm = 1;
3804
3805         permit = all_opens_permitted;
3806         if (!permit) {
3807                 for (i = 0; i < num_permitted_opens; i++)
3808                         if (open_match(&permitted_opens[i], host, port)) {
3809                                 permit = 1;
3810                                 break;
3811                         }
3812         }
3813
3814         if (num_adm_permitted_opens > 0) {
3815                 permit_adm = 0;
3816                 for (i = 0; i < num_adm_permitted_opens; i++)
3817                         if (open_match(&permitted_adm_opens[i], host, port)) {
3818                                 permit_adm = 1;
3819                                 break;
3820                         }
3821         }
3822
3823         if (!permit || !permit_adm) {
3824                 logit("Received request to connect to host %.100s port %d, "
3825                     "but the request was denied.", host, port);
3826                 return NULL;
3827         }
3828         return connect_to(host, port, ctype, rname);
3829 }
3830
3831 /* Check if connecting to that path is permitted and connect. */
3832 Channel *
3833 channel_connect_to_path(const char *path, char *ctype, char *rname)
3834 {
3835         int i, permit, permit_adm = 1;
3836
3837         permit = all_opens_permitted;
3838         if (!permit) {
3839                 for (i = 0; i < num_permitted_opens; i++)
3840                         if (open_match(&permitted_opens[i], path, PORT_STREAMLOCAL)) {
3841                                 permit = 1;
3842                                 break;
3843                         }
3844         }
3845
3846         if (num_adm_permitted_opens > 0) {
3847                 permit_adm = 0;
3848                 for (i = 0; i < num_adm_permitted_opens; i++)
3849                         if (open_match(&permitted_adm_opens[i], path, PORT_STREAMLOCAL)) {
3850                                 permit_adm = 1;
3851                                 break;
3852                         }
3853         }
3854
3855         if (!permit || !permit_adm) {
3856                 logit("Received request to connect to path %.100s, "
3857                     "but the request was denied.", path);
3858                 return NULL;
3859         }
3860         return connect_to(path, PORT_STREAMLOCAL, ctype, rname);
3861 }
3862
3863 void
3864 channel_send_window_changes(void)
3865 {
3866         u_int i;
3867         struct winsize ws;
3868
3869         for (i = 0; i < channels_alloc; i++) {
3870                 if (channels[i] == NULL || !channels[i]->client_tty ||
3871                     channels[i]->type != SSH_CHANNEL_OPEN)
3872                         continue;
3873                 if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
3874                         continue;
3875                 channel_request_start(i, "window-change", 0);
3876                 packet_put_int((u_int)ws.ws_col);
3877                 packet_put_int((u_int)ws.ws_row);
3878                 packet_put_int((u_int)ws.ws_xpixel);
3879                 packet_put_int((u_int)ws.ws_ypixel);
3880                 packet_send();
3881         }
3882 }
3883
3884 /* -- X11 forwarding */
3885
3886 /*
3887  * Creates an internet domain socket for listening for X11 connections.
3888  * Returns 0 and a suitable display number for the DISPLAY variable
3889  * stored in display_numberp , or -1 if an error occurs.
3890  */
3891 int
3892 x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
3893     int single_connection, u_int *display_numberp, int **chanids)
3894 {
3895         Channel *nc = NULL;
3896         int display_number, sock;
3897         u_short port;
3898         struct addrinfo hints, *ai, *aitop;
3899         char strport[NI_MAXSERV];
3900         int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
3901
3902         if (chanids == NULL)
3903                 return -1;
3904
3905         for (display_number = x11_display_offset;
3906             display_number < MAX_DISPLAYS;
3907             display_number++) {
3908                 port = 6000 + display_number;
3909                 memset(&hints, 0, sizeof(hints));
3910                 hints.ai_family = IPv4or6;
3911                 hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
3912                 hints.ai_socktype = SOCK_STREAM;
3913                 snprintf(strport, sizeof strport, "%d", port);
3914                 if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
3915                         error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr));
3916                         return -1;
3917                 }
3918                 for (ai = aitop; ai; ai = ai->ai_next) {
3919                         if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
3920                                 continue;
3921                         sock = socket(ai->ai_family, ai->ai_socktype,
3922                             ai->ai_protocol);
3923                         if (sock < 0) {
3924                                 if ((errno != EINVAL) && (errno != EAFNOSUPPORT)
3925 #ifdef EPFNOSUPPORT
3926                                     && (errno != EPFNOSUPPORT)
3927 #endif
3928                                     ) {
3929                                         error("socket: %.100s", strerror(errno));
3930                                         freeaddrinfo(aitop);
3931                                         return -1;
3932                                 } else {
3933                                         debug("x11_create_display_inet: Socket family %d not supported",
3934                                                  ai->ai_family);
3935                                         continue;
3936                                 }
3937                         }
3938                         if (ai->ai_family == AF_INET6)
3939                                 sock_set_v6only(sock);
3940                         if (x11_use_localhost)
3941                                 channel_set_reuseaddr(sock);
3942                         if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
3943                                 debug2("bind port %d: %.100s", port, strerror(errno));
3944                                 close(sock);
3945
3946                                 for (n = 0; n < num_socks; n++) {
3947                                         close(socks[n]);
3948                                 }
3949                                 num_socks = 0;
3950                                 break;
3951                         }
3952                         socks[num_socks++] = sock;
3953                         if (num_socks == NUM_SOCKS)
3954                                 break;
3955                 }
3956                 freeaddrinfo(aitop);
3957                 if (num_socks > 0)
3958                         break;
3959         }
3960         if (display_number >= MAX_DISPLAYS) {
3961                 error("Failed to allocate internet-domain X11 display socket.");
3962                 return -1;
3963         }
3964         /* Start listening for connections on the socket. */
3965         for (n = 0; n < num_socks; n++) {
3966                 sock = socks[n];
3967                 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) {
3968                         error("listen: %.100s", strerror(errno));
3969                         close(sock);
3970                         return -1;
3971                 }
3972         }
3973
3974         /* Allocate a channel for each socket. */
3975         *chanids = xcalloc(num_socks + 1, sizeof(**chanids));
3976         for (n = 0; n < num_socks; n++) {
3977                 sock = socks[n];
3978                 nc = channel_new("x11 listener",
3979                     SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
3980                     CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
3981                     0, "X11 inet listener", 1);
3982                 nc->single_connection = single_connection;
3983                 (*chanids)[n] = nc->self;
3984         }
3985         (*chanids)[n] = -1;
3986
3987         /* Return the display number for the DISPLAY environment variable. */
3988         *display_numberp = display_number;
3989         return (0);
3990 }
3991
3992 static int
3993 connect_local_xsocket_path(const char *pathname)
3994 {
3995         int sock;
3996         struct sockaddr_un addr;
3997
3998         sock = socket(AF_UNIX, SOCK_STREAM, 0);
3999         if (sock < 0)
4000                 error("socket: %.100s", strerror(errno));
4001         memset(&addr, 0, sizeof(addr));
4002         addr.sun_family = AF_UNIX;
4003         strlcpy(addr.sun_path, pathname, sizeof addr.sun_path);
4004         if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0)
4005                 return sock;
4006         close(sock);
4007         error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
4008         return -1;
4009 }
4010
4011 static int
4012 connect_local_xsocket(u_int dnr)
4013 {
4014         char buf[1024];
4015         snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr);
4016         return connect_local_xsocket_path(buf);
4017 }
4018
4019 int
4020 x11_connect_display(void)
4021 {
4022         u_int display_number;
4023         const char *display;
4024         char buf[1024], *cp;
4025         struct addrinfo hints, *ai, *aitop;
4026         char strport[NI_MAXSERV];
4027         int gaierr, sock = 0;
4028
4029         /* Try to open a socket for the local X server. */
4030         display = getenv("DISPLAY");
4031         if (!display) {
4032                 error("DISPLAY not set.");
4033                 return -1;
4034         }
4035         /*
4036          * Now we decode the value of the DISPLAY variable and make a
4037          * connection to the real X server.
4038          */
4039
4040         /* Check if the display is from launchd. */
4041 #ifdef __APPLE__
4042         if (strncmp(display, "/tmp/launch", 11) == 0) {
4043                 sock = connect_local_xsocket_path(display);
4044                 if (sock < 0)
4045                         return -1;
4046
4047                 /* OK, we now have a connection to the display. */
4048                 return sock;
4049         }
4050 #endif
4051         /*
4052          * Check if it is a unix domain socket.  Unix domain displays are in
4053          * one of the following formats: unix:d[.s], :d[.s], ::d[.s]
4054          */
4055         if (strncmp(display, "unix:", 5) == 0 ||
4056             display[0] == ':') {
4057                 /* Connect to the unix domain socket. */
4058                 if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) {
4059                         error("Could not parse display number from DISPLAY: %.100s",
4060                             display);
4061                         return -1;
4062                 }
4063                 /* Create a socket. */
4064                 sock = connect_local_xsocket(display_number);
4065                 if (sock < 0)
4066                         return -1;
4067
4068                 /* OK, we now have a connection to the display. */
4069                 return sock;
4070         }
4071         /*
4072          * Connect to an inet socket.  The DISPLAY value is supposedly
4073          * hostname:d[.s], where hostname may also be numeric IP address.
4074          */
4075         strlcpy(buf, display, sizeof(buf));
4076         cp = strchr(buf, ':');
4077         if (!cp) {
4078                 error("Could not find ':' in DISPLAY: %.100s", display);
4079                 return -1;
4080         }
4081         *cp = 0;
4082         /* buf now contains the host name.  But first we parse the display number. */
4083         if (sscanf(cp + 1, "%u", &display_number) != 1) {
4084                 error("Could not parse display number from DISPLAY: %.100s",
4085                     display);
4086                 return -1;
4087         }
4088
4089         /* Look up the host address */
4090         memset(&hints, 0, sizeof(hints));
4091         hints.ai_family = IPv4or6;
4092         hints.ai_socktype = SOCK_STREAM;
4093         snprintf(strport, sizeof strport, "%u", 6000 + display_number);
4094         if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
4095                 error("%.100s: unknown host. (%s)", buf,
4096                 ssh_gai_strerror(gaierr));
4097                 return -1;
4098         }
4099         for (ai = aitop; ai; ai = ai->ai_next) {
4100                 /* Create a socket. */
4101                 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
4102                 if (sock < 0) {
4103                         debug2("socket: %.100s", strerror(errno));
4104                         continue;
4105                 }
4106                 /* Connect it to the display. */
4107                 if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
4108                         debug2("connect %.100s port %u: %.100s", buf,
4109                             6000 + display_number, strerror(errno));
4110                         close(sock);
4111                         continue;
4112                 }
4113                 /* Success */
4114                 break;
4115         }
4116         freeaddrinfo(aitop);
4117         if (!ai) {
4118                 error("connect %.100s port %u: %.100s", buf, 6000 + display_number,
4119                     strerror(errno));
4120                 return -1;
4121         }
4122         set_nodelay(sock);
4123         return sock;
4124 }
4125
4126 /*
4127  * This is called when SSH_SMSG_X11_OPEN is received.  The packet contains
4128  * the remote channel number.  We should do whatever we want, and respond
4129  * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
4130  */
4131
4132 /* ARGSUSED */
4133 int
4134 x11_input_open(int type, u_int32_t seq, void *ctxt)
4135 {
4136         Channel *c = NULL;
4137         int remote_id, sock = 0;
4138         char *remote_host;
4139
4140         debug("Received X11 open request.");
4141
4142         remote_id = packet_get_int();
4143
4144         if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
4145                 remote_host = packet_get_string(NULL);
4146         } else {
4147                 remote_host = xstrdup("unknown (remote did not supply name)");
4148         }
4149         packet_check_eom();
4150
4151         /* Obtain a connection to the real X display. */
4152         sock = x11_connect_display();
4153         if (sock != -1) {
4154                 /* Allocate a channel for this connection. */
4155                 c = channel_new("connected x11 socket",
4156                     SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
4157                     remote_host, 1);
4158                 c->remote_id = remote_id;
4159                 c->force_drain = 1;
4160         }
4161         free(remote_host);
4162         if (c == NULL) {
4163                 /* Send refusal to the remote host. */
4164                 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
4165                 packet_put_int(remote_id);
4166         } else {
4167                 /* Send a confirmation to the remote host. */
4168                 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
4169                 packet_put_int(remote_id);
4170                 packet_put_int(c->self);
4171         }
4172         packet_send();
4173         return 0;
4174 }
4175
4176 /* dummy protocol handler that denies SSH-1 requests (agent/x11) */
4177 /* ARGSUSED */
4178 int
4179 deny_input_open(int type, u_int32_t seq, void *ctxt)
4180 {
4181         int rchan = packet_get_int();
4182
4183         switch (type) {
4184         case SSH_SMSG_AGENT_OPEN:
4185                 error("Warning: ssh server tried agent forwarding.");
4186                 break;
4187         case SSH_SMSG_X11_OPEN:
4188                 error("Warning: ssh server tried X11 forwarding.");
4189                 break;
4190         default:
4191                 error("deny_input_open: type %d", type);
4192                 break;
4193         }
4194         error("Warning: this is probably a break-in attempt by a malicious server.");
4195         packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
4196         packet_put_int(rchan);
4197         packet_send();
4198         return 0;
4199 }
4200
4201 /*
4202  * Requests forwarding of X11 connections, generates fake authentication
4203  * data, and enables authentication spoofing.
4204  * This should be called in the client only.
4205  */
4206 void
4207 x11_request_forwarding_with_spoofing(int client_session_id, const char *disp,
4208     const char *proto, const char *data, int want_reply)
4209 {
4210         u_int data_len = (u_int) strlen(data) / 2;
4211         u_int i, value;
4212         char *new_data;
4213         int screen_number;
4214         const char *cp;
4215         u_int32_t rnd = 0;
4216
4217         if (x11_saved_display == NULL)
4218                 x11_saved_display = xstrdup(disp);
4219         else if (strcmp(disp, x11_saved_display) != 0) {
4220                 error("x11_request_forwarding_with_spoofing: different "
4221                     "$DISPLAY already forwarded");
4222                 return;
4223         }
4224
4225         cp = strchr(disp, ':');
4226         if (cp)
4227                 cp = strchr(cp, '.');
4228         if (cp)
4229                 screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
4230         else
4231                 screen_number = 0;
4232
4233         if (x11_saved_proto == NULL) {
4234                 /* Save protocol name. */
4235                 x11_saved_proto = xstrdup(proto);
4236                 /*
4237                  * Extract real authentication data and generate fake data
4238                  * of the same length.
4239                  */
4240                 x11_saved_data = xmalloc(data_len);
4241                 x11_fake_data = xmalloc(data_len);
4242                 for (i = 0; i < data_len; i++) {
4243                         if (sscanf(data + 2 * i, "%2x", &value) != 1)
4244                                 fatal("x11_request_forwarding: bad "
4245                                     "authentication data: %.100s", data);
4246                         if (i % 4 == 0)
4247                                 rnd = arc4random();
4248                         x11_saved_data[i] = value;
4249                         x11_fake_data[i] = rnd & 0xff;
4250                         rnd >>= 8;
4251                 }
4252                 x11_saved_data_len = data_len;
4253                 x11_fake_data_len = data_len;
4254         }
4255
4256         /* Convert the fake data into hex. */
4257         new_data = tohex(x11_fake_data, data_len);
4258
4259         /* Send the request packet. */
4260         if (compat20) {
4261                 channel_request_start(client_session_id, "x11-req", want_reply);
4262                 packet_put_char(0);     /* XXX bool single connection */
4263         } else {
4264                 packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
4265         }
4266         packet_put_cstring(proto);
4267         packet_put_cstring(new_data);
4268         packet_put_int(screen_number);
4269         packet_send();
4270         packet_write_wait();
4271         free(new_data);
4272 }
4273
4274
4275 /* -- agent forwarding */
4276
4277 /* Sends a message to the server to request authentication fd forwarding. */
4278
4279 void
4280 auth_request_forwarding(void)
4281 {
4282         packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
4283         packet_send();
4284         packet_write_wait();
4285 }